forked from KolibriOS/kolibrios
3967 lines
143 KiB
C
3967 lines
143 KiB
C
/*
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This is a version (aka dlmalloc) of malloc/free/realloc written by
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Doug Lea and released to the public domain, as explained at
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http://creativecommons.org/licenses/publicdomain. Send questions,
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comments, complaints, performance data, etc to dl@cs.oswego.edu
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* Version 2.8.3 Thu Sep 22 11:16:15 2005 Doug Lea (dl at gee)
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Note: There may be an updated version of this malloc obtainable at
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ftp://gee.cs.oswego.edu/pub/misc/malloc.c
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Check before installing!
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* Quickstart
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This library is all in one file to simplify the most common usage:
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ftp it, compile it (-O3), and link it into another program. All of
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the compile-time options default to reasonable values for use on
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most platforms. You might later want to step through various
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compile-time and dynamic tuning options.
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For convenience, an include file for code using this malloc is at:
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ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.3.h
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You don't really need this .h file unless you call functions not
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defined in your system include files. The .h file contains only the
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excerpts from this file needed for using this malloc on ANSI C/C++
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systems, so long as you haven't changed compile-time options about
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naming and tuning parameters. If you do, then you can create your
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own malloc.h that does include all settings by cutting at the point
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indicated below. Note that you may already by default be using a C
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library containing a malloc that is based on some version of this
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malloc (for example in linux). You might still want to use the one
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in this file to customize settings or to avoid overheads associated
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with library versions.
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* Vital statistics:
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Supported pointer/size_t representation: 4 or 8 bytes
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size_t MUST be an unsigned type of the same width as
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pointers. (If you are using an ancient system that declares
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size_t as a signed type, or need it to be a different width
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than pointers, you can use a previous release of this malloc
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(e.g. 2.7.2) supporting these.)
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Alignment: 8 bytes (default)
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This suffices for nearly all current machines and C compilers.
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However, you can define MALLOC_ALIGNMENT to be wider than this
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if necessary (up to 128bytes), at the expense of using more space.
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Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes)
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8 or 16 bytes (if 8byte sizes)
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Each malloced chunk has a hidden word of overhead holding size
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and status information, and additional cross-check word
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if FOOTERS is defined.
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Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead)
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8-byte ptrs: 32 bytes (including overhead)
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Even a request for zero bytes (i.e., malloc(0)) returns a
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pointer to something of the minimum allocatable size.
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The maximum overhead wastage (i.e., number of extra bytes
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allocated than were requested in malloc) is less than or equal
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to the minimum size, except for requests >= mmap_threshold that
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are serviced via mmap(), where the worst case wastage is about
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32 bytes plus the remainder from a system page (the minimal
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mmap unit); typically 4096 or 8192 bytes.
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Security: static-safe; optionally more or less
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The "security" of malloc refers to the ability of malicious
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code to accentuate the effects of errors (for example, freeing
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space that is not currently malloc'ed or overwriting past the
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ends of chunks) in code that calls malloc. This malloc
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guarantees not to modify any memory locations below the base of
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heap, i.e., static variables, even in the presence of usage
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errors. The routines additionally detect most improper frees
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and reallocs. All this holds as long as the static bookkeeping
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for malloc itself is not corrupted by some other means. This
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is only one aspect of security -- these checks do not, and
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cannot, detect all possible programming errors.
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If FOOTERS is defined nonzero, then each allocated chunk
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carries an additional check word to verify that it was malloced
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from its space. These check words are the same within each
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execution of a program using malloc, but differ across
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executions, so externally crafted fake chunks cannot be
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freed. This improves security by rejecting frees/reallocs that
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could corrupt heap memory, in addition to the checks preventing
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writes to statics that are always on. This may further improve
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security at the expense of time and space overhead. (Note that
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FOOTERS may also be worth using with MSPACES.)
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By default detected errors cause the program to abort (calling
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"abort()"). You can override this to instead proceed past
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errors by defining PROCEED_ON_ERROR. In this case, a bad free
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has no effect, and a malloc that encounters a bad address
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caused by user overwrites will ignore the bad address by
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dropping pointers and indices to all known memory. This may
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be appropriate for programs that should continue if at all
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possible in the face of programming errors, although they may
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run out of memory because dropped memory is never reclaimed.
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If you don't like either of these options, you can define
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CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
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else. And if if you are sure that your program using malloc has
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no errors or vulnerabilities, you can define INSECURE to 1,
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which might (or might not) provide a small performance improvement.
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Thread-safety: NOT thread-safe unless USE_LOCKS defined
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When USE_LOCKS is defined, each public call to malloc, free,
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etc is surrounded with either a pthread mutex or a win32
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spinlock (depending on WIN32). This is not especially fast, and
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can be a major bottleneck. It is designed only to provide
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minimal protection in concurrent environments, and to provide a
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basis for extensions. If you are using malloc in a concurrent
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program, consider instead using ptmalloc, which is derived from
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a version of this malloc. (See http://www.malloc.de).
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System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
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This malloc can use unix sbrk or any emulation (invoked using
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the CALL_MORECORE macro) and/or mmap/munmap or any emulation
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(invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
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memory. On most unix systems, it tends to work best if both
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MORECORE and MMAP are enabled. On Win32, it uses emulations
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based on VirtualAlloc. It also uses common C library functions
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like memset.
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Compliance: I believe it is compliant with the Single Unix Specification
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(See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
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others as well.
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* Overview of algorithms
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This is not the fastest, most space-conserving, most portable, or
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most tunable malloc ever written. However it is among the fastest
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while also being among the most space-conserving, portable and
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tunable. Consistent balance across these factors results in a good
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general-purpose allocator for malloc-intensive programs.
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In most ways, this malloc is a best-fit allocator. Generally, it
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chooses the best-fitting existing chunk for a request, with ties
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broken in approximately least-recently-used order. (This strategy
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normally maintains low fragmentation.) However, for requests less
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than 256bytes, it deviates from best-fit when there is not an
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exactly fitting available chunk by preferring to use space adjacent
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to that used for the previous small request, as well as by breaking
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ties in approximately most-recently-used order. (These enhance
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locality of series of small allocations.) And for very large requests
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(>= 256Kb by default), it relies on system memory mapping
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facilities, if supported. (This helps avoid carrying around and
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possibly fragmenting memory used only for large chunks.)
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All operations (except malloc_stats and mallinfo) have execution
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times that are bounded by a constant factor of the number of bits in
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a size_t, not counting any clearing in calloc or copying in realloc,
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or actions surrounding MORECORE and MMAP that have times
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proportional to the number of non-contiguous regions returned by
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system allocation routines, which is often just 1.
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The implementation is not very modular and seriously overuses
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macros. Perhaps someday all C compilers will do as good a job
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inlining modular code as can now be done by brute-force expansion,
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but now, enough of them seem not to.
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Some compilers issue a lot of warnings about code that is
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dead/unreachable only on some platforms, and also about intentional
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uses of negation on unsigned types. All known cases of each can be
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ignored.
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For a longer but out of date high-level description, see
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http://gee.cs.oswego.edu/dl/html/malloc.html
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* MSPACES
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If MSPACES is defined, then in addition to malloc, free, etc.,
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this file also defines mspace_malloc, mspace_free, etc. These
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are versions of malloc routines that take an "mspace" argument
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obtained using create_mspace, to control all internal bookkeeping.
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If ONLY_MSPACES is defined, only these versions are compiled.
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So if you would like to use this allocator for only some allocations,
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and your system malloc for others, you can compile with
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ONLY_MSPACES and then do something like...
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static mspace mymspace = create_mspace(0,0); // for example
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#define mymalloc(bytes) mspace_malloc(mymspace, bytes)
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(Note: If you only need one instance of an mspace, you can instead
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use "USE_DL_PREFIX" to relabel the global malloc.)
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You can similarly create thread-local allocators by storing
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mspaces as thread-locals. For example:
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static __thread mspace tlms = 0;
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void* tlmalloc(size_t bytes) {
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if (tlms == 0) tlms = create_mspace(0, 0);
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return mspace_malloc(tlms, bytes);
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}
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void tlfree(void* mem) { mspace_free(tlms, mem); }
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Unless FOOTERS is defined, each mspace is completely independent.
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You cannot allocate from one and free to another (although
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conformance is only weakly checked, so usage errors are not always
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caught). If FOOTERS is defined, then each chunk carries around a tag
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indicating its originating mspace, and frees are directed to their
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originating spaces.
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------------------------- Compile-time options ---------------------------
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Be careful in setting #define values for numerical constants of type
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size_t. On some systems, literal values are not automatically extended
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to size_t precision unless they are explicitly casted.
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WIN32 default: defined if _WIN32 defined
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Defining WIN32 sets up defaults for MS environment and compilers.
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Otherwise defaults are for unix.
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MALLOC_ALIGNMENT default: (size_t)8
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Controls the minimum alignment for malloc'ed chunks. It must be a
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power of two and at least 8, even on machines for which smaller
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alignments would suffice. It may be defined as larger than this
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though. Note however that code and data structures are optimized for
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the case of 8-byte alignment.
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MSPACES default: 0 (false)
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If true, compile in support for independent allocation spaces.
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This is only supported if HAVE_MMAP is true.
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ONLY_MSPACES default: 0 (false)
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If true, only compile in mspace versions, not regular versions.
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USE_LOCKS default: 0 (false)
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Causes each call to each public routine to be surrounded with
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pthread or WIN32 mutex lock/unlock. (If set true, this can be
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overridden on a per-mspace basis for mspace versions.)
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FOOTERS default: 0
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If true, provide extra checking and dispatching by placing
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information in the footers of allocated chunks. This adds
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space and time overhead.
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INSECURE default: 0
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If true, omit checks for usage errors and heap space overwrites.
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USE_DL_PREFIX default: NOT defined
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Causes compiler to prefix all public routines with the string 'dl'.
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This can be useful when you only want to use this malloc in one part
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of a program, using your regular system malloc elsewhere.
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ABORT default: defined as abort()
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Defines how to abort on failed checks. On most systems, a failed
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check cannot die with an "assert" or even print an informative
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message, because the underlying print routines in turn call malloc,
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which will fail again. Generally, the best policy is to simply call
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abort(). It's not very useful to do more than this because many
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errors due to overwriting will show up as address faults (null, odd
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addresses etc) rather than malloc-triggered checks, so will also
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abort. Also, most compilers know that abort() does not return, so
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can better optimize code conditionally calling it.
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PROCEED_ON_ERROR default: defined as 0 (false)
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Controls whether detected bad addresses cause them to bypassed
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rather than aborting. If set, detected bad arguments to free and
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realloc are ignored. And all bookkeeping information is zeroed out
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upon a detected overwrite of freed heap space, thus losing the
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ability to ever return it from malloc again, but enabling the
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application to proceed. If PROCEED_ON_ERROR is defined, the
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static variable malloc_corruption_error_count is compiled in
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and can be examined to see if errors have occurred. This option
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generates slower code than the default abort policy.
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DEBUG default: NOT defined
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The DEBUG setting is mainly intended for people trying to modify
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this code or diagnose problems when porting to new platforms.
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However, it may also be able to better isolate user errors than just
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using runtime checks. The assertions in the check routines spell
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out in more detail the assumptions and invariants underlying the
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algorithms. The checking is fairly extensive, and will slow down
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execution noticeably. Calling malloc_stats or mallinfo with DEBUG
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set will attempt to check every non-mmapped allocated and free chunk
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in the course of computing the summaries.
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ABORT_ON_ASSERT_FAILURE default: defined as 1 (true)
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Debugging assertion failures can be nearly impossible if your
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version of the assert macro causes malloc to be called, which will
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lead to a cascade of further failures, blowing the runtime stack.
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ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
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which will usually make debugging easier.
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MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32
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The action to take before "return 0" when malloc fails to be able to
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return memory because there is none available.
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HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES
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True if this system supports sbrk or an emulation of it.
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MORECORE default: sbrk
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The name of the sbrk-style system routine to call to obtain more
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memory. See below for guidance on writing custom MORECORE
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functions. The type of the argument to sbrk/MORECORE varies across
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systems. It cannot be size_t, because it supports negative
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arguments, so it is normally the signed type of the same width as
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size_t (sometimes declared as "intptr_t"). It doesn't much matter
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though. Internally, we only call it with arguments less than half
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the max value of a size_t, which should work across all reasonable
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possibilities, although sometimes generating compiler warnings. See
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near the end of this file for guidelines for creating a custom
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version of MORECORE.
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MORECORE_CONTIGUOUS default: 1 (true)
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If true, take advantage of fact that consecutive calls to MORECORE
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with positive arguments always return contiguous increasing
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addresses. This is true of unix sbrk. It does not hurt too much to
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set it true anyway, since malloc copes with non-contiguities.
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Setting it false when definitely non-contiguous saves time
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and possibly wasted space it would take to discover this though.
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MORECORE_CANNOT_TRIM default: NOT defined
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True if MORECORE cannot release space back to the system when given
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negative arguments. This is generally necessary only if you are
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using a hand-crafted MORECORE function that cannot handle negative
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arguments.
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HAVE_MMAP default: 1 (true)
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True if this system supports mmap or an emulation of it. If so, and
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HAVE_MORECORE is not true, MMAP is used for all system
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allocation. If set and HAVE_MORECORE is true as well, MMAP is
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primarily used to directly allocate very large blocks. It is also
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used as a backup strategy in cases where MORECORE fails to provide
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space from system. Note: A single call to MUNMAP is assumed to be
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able to unmap memory that may have be allocated using multiple calls
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to MMAP, so long as they are adjacent.
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HAVE_MREMAP default: 1 on linux, else 0
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If true realloc() uses mremap() to re-allocate large blocks and
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extend or shrink allocation spaces.
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MMAP_CLEARS default: 1 on unix
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True if mmap clears memory so calloc doesn't need to. This is true
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for standard unix mmap using /dev/zero.
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USE_BUILTIN_FFS default: 0 (i.e., not used)
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Causes malloc to use the builtin ffs() function to compute indices.
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Some compilers may recognize and intrinsify ffs to be faster than the
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supplied C version. Also, the case of x86 using gcc is special-cased
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to an asm instruction, so is already as fast as it can be, and so
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this setting has no effect. (On most x86s, the asm version is only
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slightly faster than the C version.)
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malloc_getpagesize default: derive from system includes, or 4096.
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The system page size. To the extent possible, this malloc manages
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memory from the system in page-size units. This may be (and
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usually is) a function rather than a constant. This is ignored
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if WIN32, where page size is determined using getSystemInfo during
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initialization.
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USE_DEV_RANDOM default: 0 (i.e., not used)
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Causes malloc to use /dev/random to initialize secure magic seed for
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stamping footers. Otherwise, the current time is used.
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NO_MALLINFO default: 0
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If defined, don't compile "mallinfo". This can be a simple way
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of dealing with mismatches between system declarations and
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those in this file.
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MALLINFO_FIELD_TYPE default: size_t
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The type of the fields in the mallinfo struct. This was originally
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defined as "int" in SVID etc, but is more usefully defined as
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size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set
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REALLOC_ZERO_BYTES_FREES default: not defined
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This should be set if a call to realloc with zero bytes should
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be the same as a call to free. Some people think it should. Otherwise,
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since this malloc returns a unique pointer for malloc(0), so does
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realloc(p, 0).
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LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
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LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H
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LACKS_STDLIB_H default: NOT defined unless on WIN32
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Define these if your system does not have these header files.
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You might need to manually insert some of the declarations they provide.
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DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS,
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system_info.dwAllocationGranularity in WIN32,
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otherwise 64K.
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Also settable using mallopt(M_GRANULARITY, x)
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The unit for allocating and deallocating memory from the system. On
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most systems with contiguous MORECORE, there is no reason to
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make this more than a page. However, systems with MMAP tend to
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either require or encourage larger granularities. You can increase
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this value to prevent system allocation functions to be called so
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often, especially if they are slow. The value must be at least one
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page and must be a power of two. Setting to 0 causes initialization
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to either page size or win32 region size. (Note: In previous
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versions of malloc, the equivalent of this option was called
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"TOP_PAD")
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DEFAULT_TRIM_THRESHOLD default: 2MB
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Also settable using mallopt(M_TRIM_THRESHOLD, x)
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The maximum amount of unused top-most memory to keep before
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releasing via malloc_trim in free(). Automatic trimming is mainly
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useful in long-lived programs using contiguous MORECORE. Because
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trimming via sbrk can be slow on some systems, and can sometimes be
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wasteful (in cases where programs immediately afterward allocate
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more large chunks) the value should be high enough so that your
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overall system performance would improve by releasing this much
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memory. As a rough guide, you might set to a value close to the
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average size of a process (program) running on your system.
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Releasing this much memory would allow such a process to run in
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memory. Generally, it is worth tuning trim thresholds when a
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program undergoes phases where several large chunks are allocated
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and released in ways that can reuse each other's storage, perhaps
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mixed with phases where there are no such chunks at all. The trim
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value must be greater than page size to have any useful effect. To
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disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
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some people use of mallocing a huge space and then freeing it at
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program startup, in an attempt to reserve system memory, doesn't
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have the intended effect under automatic trimming, since that memory
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will immediately be returned to the system.
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DEFAULT_MMAP_THRESHOLD default: 256K
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Also settable using mallopt(M_MMAP_THRESHOLD, x)
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The request size threshold for using MMAP to directly service a
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request. Requests of at least this size that cannot be allocated
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using already-existing space will be serviced via mmap. (If enough
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normal freed space already exists it is used instead.) Using mmap
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segregates relatively large chunks of memory so that they can be
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individually obtained and released from the host system. A request
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serviced through mmap is never reused by any other request (at least
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not directly; the system may just so happen to remap successive
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requests to the same locations). Segregating space in this way has
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the benefits that: Mmapped space can always be individually released
|
|
back to the system, which helps keep the system level memory demands
|
|
of a long-lived program low. Also, mapped memory doesn't become
|
|
`locked' between other chunks, as can happen with normally allocated
|
|
chunks, which means that even trimming via malloc_trim would not
|
|
release them. However, it has the disadvantage that the space
|
|
cannot be reclaimed, consolidated, and then used to service later
|
|
requests, as happens with normal chunks. The advantages of mmap
|
|
nearly always outweigh disadvantages for "large" chunks, but the
|
|
value of "large" may vary across systems. The default is an
|
|
empirically derived value that works well in most systems. You can
|
|
disable mmap by setting to MAX_SIZE_T.
|
|
|
|
*/
|
|
|
|
#define STDCALL __attribute__ ((stdcall)) __attribute__ ((dllimport))
|
|
void* STDCALL KernelAlloc(unsigned size)__asm__("KernelAlloc");
|
|
int KernelFree(void*);
|
|
|
|
#define MALLOC_ALIGNMENT ((size_t)8U)
|
|
#define DEFAULT_MMAP_THRESHOLD ((size_t)32U * (size_t)1024U)
|
|
#define NO_MALLINFO 1
|
|
#define HAVE_MMAP 1
|
|
#define MORECORE_CANNOT_TRIM
|
|
#define FOOTERS 0
|
|
#define ABORT
|
|
|
|
#ifndef WIN32
|
|
#ifdef _WIN32
|
|
#define WIN32 1
|
|
#endif /* _WIN32 */
|
|
#endif /* WIN32 */
|
|
#ifdef WIN32
|
|
#define WIN32_LEAN_AND_MEAN
|
|
#include <windows.h>
|
|
#define HAVE_MMAP 1
|
|
#define HAVE_MORECORE 0
|
|
#define LACKS_UNISTD_H
|
|
#define LACKS_SYS_PARAM_H
|
|
#define LACKS_SYS_MMAN_H
|
|
#define LACKS_STRING_H
|
|
#define LACKS_STRINGS_H
|
|
#define LACKS_SYS_TYPES_H
|
|
#define LACKS_ERRNO_H
|
|
#define MALLOC_FAILURE_ACTION
|
|
#define MMAP_CLEARS 0 /* WINCE and some others apparently don't clear */
|
|
#endif /* WIN32 */
|
|
|
|
#if defined(DARWIN) || defined(_DARWIN)
|
|
/* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
|
|
#ifndef HAVE_MORECORE
|
|
#define HAVE_MORECORE 0
|
|
#define HAVE_MMAP 1
|
|
#endif /* HAVE_MORECORE */
|
|
#endif /* DARWIN */
|
|
|
|
#ifndef LACKS_SYS_TYPES_H
|
|
#include <sys/types.h> /* For size_t */
|
|
#endif /* LACKS_SYS_TYPES_H */
|
|
|
|
/* The maximum possible size_t value has all bits set */
|
|
#define MAX_SIZE_T (~(size_t)0)
|
|
|
|
#ifndef ONLY_MSPACES
|
|
#define ONLY_MSPACES 0
|
|
#endif /* ONLY_MSPACES */
|
|
#ifndef MSPACES
|
|
#if ONLY_MSPACES
|
|
#define MSPACES 1
|
|
#else /* ONLY_MSPACES */
|
|
#define MSPACES 0
|
|
#endif /* ONLY_MSPACES */
|
|
#endif /* MSPACES */
|
|
#ifndef MALLOC_ALIGNMENT
|
|
#define MALLOC_ALIGNMENT ((size_t)8U)
|
|
#endif /* MALLOC_ALIGNMENT */
|
|
#ifndef FOOTERS
|
|
#define FOOTERS 0
|
|
#endif /* FOOTERS */
|
|
#ifndef ABORT
|
|
#define ABORT abort()
|
|
#endif /* ABORT */
|
|
#ifndef ABORT_ON_ASSERT_FAILURE
|
|
#define ABORT_ON_ASSERT_FAILURE 1
|
|
#endif /* ABORT_ON_ASSERT_FAILURE */
|
|
#ifndef PROCEED_ON_ERROR
|
|
#define PROCEED_ON_ERROR 0
|
|
#endif /* PROCEED_ON_ERROR */
|
|
#ifndef USE_LOCKS
|
|
#define USE_LOCKS 0
|
|
#endif /* USE_LOCKS */
|
|
#ifndef INSECURE
|
|
#define INSECURE 0
|
|
#endif /* INSECURE */
|
|
#ifndef HAVE_MMAP
|
|
#define HAVE_MMAP 1
|
|
#endif /* HAVE_MMAP */
|
|
#ifndef MMAP_CLEARS
|
|
#define MMAP_CLEARS 1
|
|
#endif /* MMAP_CLEARS */
|
|
#ifndef HAVE_MREMAP
|
|
#ifdef linux
|
|
#define HAVE_MREMAP 1
|
|
#else /* linux */
|
|
#define HAVE_MREMAP 0
|
|
#endif /* linux */
|
|
#endif /* HAVE_MREMAP */
|
|
#ifndef MALLOC_FAILURE_ACTION
|
|
#define MALLOC_FAILURE_ACTION errno = ENOMEM;
|
|
#endif /* MALLOC_FAILURE_ACTION */
|
|
#ifndef HAVE_MORECORE
|
|
#if ONLY_MSPACES
|
|
#define HAVE_MORECORE 0
|
|
#else /* ONLY_MSPACES */
|
|
#define HAVE_MORECORE 1
|
|
#endif /* ONLY_MSPACES */
|
|
#endif /* HAVE_MORECORE */
|
|
#if !HAVE_MORECORE
|
|
#define MORECORE_CONTIGUOUS 0
|
|
#else /* !HAVE_MORECORE */
|
|
#ifndef MORECORE
|
|
#define MORECORE sbrk
|
|
#endif /* MORECORE */
|
|
#ifndef MORECORE_CONTIGUOUS
|
|
#define MORECORE_CONTIGUOUS 1
|
|
#endif /* MORECORE_CONTIGUOUS */
|
|
#endif /* HAVE_MORECORE */
|
|
#ifndef DEFAULT_GRANULARITY
|
|
#if MORECORE_CONTIGUOUS
|
|
#define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */
|
|
#else /* MORECORE_CONTIGUOUS */
|
|
#define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
|
|
#endif /* MORECORE_CONTIGUOUS */
|
|
#endif /* DEFAULT_GRANULARITY */
|
|
#ifndef DEFAULT_TRIM_THRESHOLD
|
|
#ifndef MORECORE_CANNOT_TRIM
|
|
#define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
|
|
#else /* MORECORE_CANNOT_TRIM */
|
|
#define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
|
|
#endif /* MORECORE_CANNOT_TRIM */
|
|
#endif /* DEFAULT_TRIM_THRESHOLD */
|
|
#ifndef DEFAULT_MMAP_THRESHOLD
|
|
#if HAVE_MMAP
|
|
#define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
|
|
#else /* HAVE_MMAP */
|
|
#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
|
|
#endif /* HAVE_MMAP */
|
|
#endif /* DEFAULT_MMAP_THRESHOLD */
|
|
#ifndef USE_BUILTIN_FFS
|
|
#define USE_BUILTIN_FFS 0
|
|
#endif /* USE_BUILTIN_FFS */
|
|
#ifndef USE_DEV_RANDOM
|
|
#define USE_DEV_RANDOM 0
|
|
#endif /* USE_DEV_RANDOM */
|
|
#ifndef NO_MALLINFO
|
|
#define NO_MALLINFO 0
|
|
#endif /* NO_MALLINFO */
|
|
#ifndef MALLINFO_FIELD_TYPE
|
|
#define MALLINFO_FIELD_TYPE size_t
|
|
#endif /* MALLINFO_FIELD_TYPE */
|
|
|
|
|
|
/*
|
|
mallopt tuning options. SVID/XPG defines four standard parameter
|
|
numbers for mallopt, normally defined in malloc.h. None of these
|
|
are used in this malloc, so setting them has no effect. But this
|
|
malloc does support the following options.
|
|
*/
|
|
|
|
#define M_TRIM_THRESHOLD (-1)
|
|
#define M_GRANULARITY (-2)
|
|
#define M_MMAP_THRESHOLD (-3)
|
|
|
|
/* ------------------------ Mallinfo declarations ------------------------ */
|
|
|
|
#if !NO_MALLINFO
|
|
#endif /* NO_MALLINFO */
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif /* __cplusplus */
|
|
|
|
#if !ONLY_MSPACES
|
|
|
|
/* ------------------- Declarations of public routines ------------------- */
|
|
|
|
#ifndef USE_DL_PREFIX
|
|
#define dlcalloc calloc
|
|
#define dlfree free
|
|
#define dlmalloc malloc
|
|
#define dlmemalign memalign
|
|
#define dlrealloc realloc
|
|
#define dlvalloc valloc
|
|
#define dlpvalloc pvalloc
|
|
#define dlmallinfo mallinfo
|
|
#define dlmallopt mallopt
|
|
#define dlmalloc_trim malloc_trim
|
|
#define dlmalloc_stats malloc_stats
|
|
#define dlmalloc_usable_size malloc_usable_size
|
|
#define dlmalloc_footprint malloc_footprint
|
|
#define dlmalloc_max_footprint malloc_max_footprint
|
|
#define dlindependent_calloc independent_calloc
|
|
#define dlindependent_comalloc independent_comalloc
|
|
#endif /* USE_DL_PREFIX */
|
|
|
|
|
|
/*
|
|
malloc(size_t n)
|
|
Returns a pointer to a newly allocated chunk of at least n bytes, or
|
|
null if no space is available, in which case errno is set to ENOMEM
|
|
on ANSI C systems.
|
|
|
|
If n is zero, malloc returns a minimum-sized chunk. (The minimum
|
|
size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
|
|
systems.) Note that size_t is an unsigned type, so calls with
|
|
arguments that would be negative if signed are interpreted as
|
|
requests for huge amounts of space, which will often fail. The
|
|
maximum supported value of n differs across systems, but is in all
|
|
cases less than the maximum representable value of a size_t.
|
|
*/
|
|
void* dlmalloc(size_t);
|
|
|
|
/*
|
|
free(void* p)
|
|
Releases the chunk of memory pointed to by p, that had been previously
|
|
allocated using malloc or a related routine such as realloc.
|
|
It has no effect if p is null. If p was not malloced or already
|
|
freed, free(p) will by default cause the current program to abort.
|
|
*/
|
|
void dlfree(void*);
|
|
|
|
/*
|
|
calloc(size_t n_elements, size_t element_size);
|
|
Returns a pointer to n_elements * element_size bytes, with all locations
|
|
set to zero.
|
|
*/
|
|
void* dlcalloc(size_t, size_t);
|
|
|
|
/*
|
|
realloc(void* p, size_t n)
|
|
Returns a pointer to a chunk of size n that contains the same data
|
|
as does chunk p up to the minimum of (n, p's size) bytes, or null
|
|
if no space is available.
|
|
|
|
The returned pointer may or may not be the same as p. The algorithm
|
|
prefers extending p in most cases when possible, otherwise it
|
|
employs the equivalent of a malloc-copy-free sequence.
|
|
|
|
If p is null, realloc is equivalent to malloc.
|
|
|
|
If space is not available, realloc returns null, errno is set (if on
|
|
ANSI) and p is NOT freed.
|
|
|
|
if n is for fewer bytes than already held by p, the newly unused
|
|
space is lopped off and freed if possible. realloc with a size
|
|
argument of zero (re)allocates a minimum-sized chunk.
|
|
|
|
The old unix realloc convention of allowing the last-free'd chunk
|
|
to be used as an argument to realloc is not supported.
|
|
*/
|
|
|
|
void* dlrealloc(void*, size_t);
|
|
|
|
/*
|
|
memalign(size_t alignment, size_t n);
|
|
Returns a pointer to a newly allocated chunk of n bytes, aligned
|
|
in accord with the alignment argument.
|
|
|
|
The alignment argument should be a power of two. If the argument is
|
|
not a power of two, the nearest greater power is used.
|
|
8-byte alignment is guaranteed by normal malloc calls, so don't
|
|
bother calling memalign with an argument of 8 or less.
|
|
|
|
Overreliance on memalign is a sure way to fragment space.
|
|
*/
|
|
void* dlmemalign(size_t, size_t);
|
|
|
|
/*
|
|
valloc(size_t n);
|
|
Equivalent to memalign(pagesize, n), where pagesize is the page
|
|
size of the system. If the pagesize is unknown, 4096 is used.
|
|
*/
|
|
void* dlvalloc(size_t);
|
|
|
|
/*
|
|
mallopt(int parameter_number, int parameter_value)
|
|
Sets tunable parameters The format is to provide a
|
|
(parameter-number, parameter-value) pair. mallopt then sets the
|
|
corresponding parameter to the argument value if it can (i.e., so
|
|
long as the value is meaningful), and returns 1 if successful else
|
|
0. SVID/XPG/ANSI defines four standard param numbers for mallopt,
|
|
normally defined in malloc.h. None of these are use in this malloc,
|
|
so setting them has no effect. But this malloc also supports other
|
|
options in mallopt. See below for details. Briefly, supported
|
|
parameters are as follows (listed defaults are for "typical"
|
|
configurations).
|
|
|
|
Symbol param # default allowed param values
|
|
M_TRIM_THRESHOLD -1 2*1024*1024 any (MAX_SIZE_T disables)
|
|
M_GRANULARITY -2 page size any power of 2 >= page size
|
|
M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support)
|
|
*/
|
|
int dlmallopt(int, int);
|
|
|
|
/*
|
|
malloc_footprint();
|
|
Returns the number of bytes obtained from the system. The total
|
|
number of bytes allocated by malloc, realloc etc., is less than this
|
|
value. Unlike mallinfo, this function returns only a precomputed
|
|
result, so can be called frequently to monitor memory consumption.
|
|
Even if locks are otherwise defined, this function does not use them,
|
|
so results might not be up to date.
|
|
*/
|
|
size_t dlmalloc_footprint(void);
|
|
|
|
/*
|
|
malloc_max_footprint();
|
|
Returns the maximum number of bytes obtained from the system. This
|
|
value will be greater than current footprint if deallocated space
|
|
has been reclaimed by the system. The peak number of bytes allocated
|
|
by malloc, realloc etc., is less than this value. Unlike mallinfo,
|
|
this function returns only a precomputed result, so can be called
|
|
frequently to monitor memory consumption. Even if locks are
|
|
otherwise defined, this function does not use them, so results might
|
|
not be up to date.
|
|
*/
|
|
size_t dlmalloc_max_footprint(void);
|
|
|
|
#if !NO_MALLINFO
|
|
#endif /* NO_MALLINFO */
|
|
|
|
/*
|
|
independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
|
|
|
|
independent_calloc is similar to calloc, but instead of returning a
|
|
single cleared space, it returns an array of pointers to n_elements
|
|
independent elements that can hold contents of size elem_size, each
|
|
of which starts out cleared, and can be independently freed,
|
|
realloc'ed etc. The elements are guaranteed to be adjacently
|
|
allocated (this is not guaranteed to occur with multiple callocs or
|
|
mallocs), which may also improve cache locality in some
|
|
applications.
|
|
|
|
The "chunks" argument is optional (i.e., may be null, which is
|
|
probably the most typical usage). If it is null, the returned array
|
|
is itself dynamically allocated and should also be freed when it is
|
|
no longer needed. Otherwise, the chunks array must be of at least
|
|
n_elements in length. It is filled in with the pointers to the
|
|
chunks.
|
|
|
|
In either case, independent_calloc returns this pointer array, or
|
|
null if the allocation failed. If n_elements is zero and "chunks"
|
|
is null, it returns a chunk representing an array with zero elements
|
|
(which should be freed if not wanted).
|
|
|
|
Each element must be individually freed when it is no longer
|
|
needed. If you'd like to instead be able to free all at once, you
|
|
should instead use regular calloc and assign pointers into this
|
|
space to represent elements. (In this case though, you cannot
|
|
independently free elements.)
|
|
|
|
independent_calloc simplifies and speeds up implementations of many
|
|
kinds of pools. It may also be useful when constructing large data
|
|
structures that initially have a fixed number of fixed-sized nodes,
|
|
but the number is not known at compile time, and some of the nodes
|
|
may later need to be freed. For example:
|
|
|
|
struct Node { int item; struct Node* next; };
|
|
|
|
struct Node* build_list() {
|
|
struct Node** pool;
|
|
int n = read_number_of_nodes_needed();
|
|
if (n <= 0) return 0;
|
|
pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
|
|
if (pool == 0) die();
|
|
// organize into a linked list...
|
|
struct Node* first = pool[0];
|
|
for (i = 0; i < n-1; ++i)
|
|
pool[i]->next = pool[i+1];
|
|
free(pool); // Can now free the array (or not, if it is needed later)
|
|
return first;
|
|
}
|
|
*/
|
|
void** dlindependent_calloc(size_t, size_t, void**);
|
|
|
|
/*
|
|
independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
|
|
|
|
independent_comalloc allocates, all at once, a set of n_elements
|
|
chunks with sizes indicated in the "sizes" array. It returns
|
|
an array of pointers to these elements, each of which can be
|
|
independently freed, realloc'ed etc. The elements are guaranteed to
|
|
be adjacently allocated (this is not guaranteed to occur with
|
|
multiple callocs or mallocs), which may also improve cache locality
|
|
in some applications.
|
|
|
|
The "chunks" argument is optional (i.e., may be null). If it is null
|
|
the returned array is itself dynamically allocated and should also
|
|
be freed when it is no longer needed. Otherwise, the chunks array
|
|
must be of at least n_elements in length. It is filled in with the
|
|
pointers to the chunks.
|
|
|
|
In either case, independent_comalloc returns this pointer array, or
|
|
null if the allocation failed. If n_elements is zero and chunks is
|
|
null, it returns a chunk representing an array with zero elements
|
|
(which should be freed if not wanted).
|
|
|
|
Each element must be individually freed when it is no longer
|
|
needed. If you'd like to instead be able to free all at once, you
|
|
should instead use a single regular malloc, and assign pointers at
|
|
particular offsets in the aggregate space. (In this case though, you
|
|
cannot independently free elements.)
|
|
|
|
independent_comallac differs from independent_calloc in that each
|
|
element may have a different size, and also that it does not
|
|
automatically clear elements.
|
|
|
|
independent_comalloc can be used to speed up allocation in cases
|
|
where several structs or objects must always be allocated at the
|
|
same time. For example:
|
|
|
|
struct Head { ... }
|
|
struct Foot { ... }
|
|
|
|
void send_message(char* msg) {
|
|
int msglen = strlen(msg);
|
|
size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
|
|
void* chunks[3];
|
|
if (independent_comalloc(3, sizes, chunks) == 0)
|
|
die();
|
|
struct Head* head = (struct Head*)(chunks[0]);
|
|
char* body = (char*)(chunks[1]);
|
|
struct Foot* foot = (struct Foot*)(chunks[2]);
|
|
// ...
|
|
}
|
|
|
|
In general though, independent_comalloc is worth using only for
|
|
larger values of n_elements. For small values, you probably won't
|
|
detect enough difference from series of malloc calls to bother.
|
|
|
|
Overuse of independent_comalloc can increase overall memory usage,
|
|
since it cannot reuse existing noncontiguous small chunks that
|
|
might be available for some of the elements.
|
|
*/
|
|
void** dlindependent_comalloc(size_t, size_t*, void**);
|
|
|
|
|
|
/*
|
|
pvalloc(size_t n);
|
|
Equivalent to valloc(minimum-page-that-holds(n)), that is,
|
|
round up n to nearest pagesize.
|
|
*/
|
|
void* dlpvalloc(size_t);
|
|
|
|
/*
|
|
malloc_trim(size_t pad);
|
|
|
|
If possible, gives memory back to the system (via negative arguments
|
|
to sbrk) if there is unused memory at the `high' end of the malloc
|
|
pool or in unused MMAP segments. You can call this after freeing
|
|
large blocks of memory to potentially reduce the system-level memory
|
|
requirements of a program. However, it cannot guarantee to reduce
|
|
memory. Under some allocation patterns, some large free blocks of
|
|
memory will be locked between two used chunks, so they cannot be
|
|
given back to the system.
|
|
|
|
The `pad' argument to malloc_trim represents the amount of free
|
|
trailing space to leave untrimmed. If this argument is zero, only
|
|
the minimum amount of memory to maintain internal data structures
|
|
will be left. Non-zero arguments can be supplied to maintain enough
|
|
trailing space to service future expected allocations without having
|
|
to re-obtain memory from the system.
|
|
|
|
Malloc_trim returns 1 if it actually released any memory, else 0.
|
|
*/
|
|
int dlmalloc_trim(size_t);
|
|
|
|
/*
|
|
malloc_usable_size(void* p);
|
|
|
|
Returns the number of bytes you can actually use in
|
|
an allocated chunk, which may be more than you requested (although
|
|
often not) due to alignment and minimum size constraints.
|
|
You can use this many bytes without worrying about
|
|
overwriting other allocated objects. This is not a particularly great
|
|
programming practice. malloc_usable_size can be more useful in
|
|
debugging and assertions, for example:
|
|
|
|
p = malloc(n);
|
|
assert(malloc_usable_size(p) >= 256);
|
|
*/
|
|
size_t dlmalloc_usable_size(void*);
|
|
|
|
/*
|
|
malloc_stats();
|
|
Prints on stderr the amount of space obtained from the system (both
|
|
via sbrk and mmap), the maximum amount (which may be more than
|
|
current if malloc_trim and/or munmap got called), and the current
|
|
number of bytes allocated via malloc (or realloc, etc) but not yet
|
|
freed. Note that this is the number of bytes allocated, not the
|
|
number requested. It will be larger than the number requested
|
|
because of alignment and bookkeeping overhead. Because it includes
|
|
alignment wastage as being in use, this figure may be greater than
|
|
zero even when no user-level chunks are allocated.
|
|
|
|
The reported current and maximum system memory can be inaccurate if
|
|
a program makes other calls to system memory allocation functions
|
|
(normally sbrk) outside of malloc.
|
|
|
|
malloc_stats prints only the most commonly interesting statistics.
|
|
More information can be obtained by calling mallinfo.
|
|
*/
|
|
void dlmalloc_stats(void);
|
|
|
|
#endif /* ONLY_MSPACES */
|
|
|
|
#if MSPACES
|
|
#endif /* MSPACES */
|
|
|
|
#ifdef __cplusplus
|
|
}; /* end of extern "C" */
|
|
#endif /* __cplusplus */
|
|
|
|
/*
|
|
========================================================================
|
|
To make a fully customizable malloc.h header file, cut everything
|
|
above this line, put into file malloc.h, edit to suit, and #include it
|
|
on the next line, as well as in programs that use this malloc.
|
|
========================================================================
|
|
*/
|
|
|
|
/* #include "malloc.h" */
|
|
|
|
/*------------------------------ internal #includes ---------------------- */
|
|
|
|
#ifdef WIN32
|
|
#pragma warning( disable : 4146 ) /* no "unsigned" warnings */
|
|
#endif /* WIN32 */
|
|
|
|
#include <stdio.h> /* for printing in malloc_stats */
|
|
|
|
#ifndef LACKS_ERRNO_H
|
|
#include <errno.h> /* for MALLOC_FAILURE_ACTION */
|
|
#endif /* LACKS_ERRNO_H */
|
|
#if FOOTERS
|
|
#include <time.h> /* for magic initialization */
|
|
#endif /* FOOTERS */
|
|
#ifndef LACKS_STDLIB_H
|
|
#include <stdlib.h> /* for abort() */
|
|
#endif /* LACKS_STDLIB_H */
|
|
#ifdef DEBUG
|
|
#if ABORT_ON_ASSERT_FAILURE
|
|
#define assert(x) if(!(x)) ABORT
|
|
#else /* ABORT_ON_ASSERT_FAILURE */
|
|
#include <assert.h>
|
|
#endif /* ABORT_ON_ASSERT_FAILURE */
|
|
#else /* DEBUG */
|
|
#define assert(x)
|
|
#endif /* DEBUG */
|
|
#ifndef LACKS_STRING_H
|
|
#include <string.h> /* for memset etc */
|
|
#endif /* LACKS_STRING_H */
|
|
#if USE_BUILTIN_FFS
|
|
#ifndef LACKS_STRINGS_H
|
|
#include <strings.h> /* for ffs */
|
|
#endif /* LACKS_STRINGS_H */
|
|
#endif /* USE_BUILTIN_FFS */
|
|
#if HAVE_MMAP
|
|
#ifndef LACKS_SYS_MMAN_H
|
|
#include <sys/mman.h> /* for mmap */
|
|
#endif /* LACKS_SYS_MMAN_H */
|
|
#ifndef LACKS_FCNTL_H
|
|
#include <fcntl.h>
|
|
#endif /* LACKS_FCNTL_H */
|
|
#endif /* HAVE_MMAP */
|
|
#if HAVE_MORECORE
|
|
#endif /* HAVE_MMAP */
|
|
|
|
#ifndef WIN32
|
|
#endif
|
|
|
|
/* ------------------- size_t and alignment properties -------------------- */
|
|
|
|
/* The byte and bit size of a size_t */
|
|
#define SIZE_T_SIZE (sizeof(size_t))
|
|
#define SIZE_T_BITSIZE (sizeof(size_t) << 3)
|
|
|
|
/* Some constants coerced to size_t */
|
|
/* Annoying but necessary to avoid errors on some plaftorms */
|
|
#define SIZE_T_ZERO ((size_t)0)
|
|
#define SIZE_T_ONE ((size_t)1)
|
|
#define SIZE_T_TWO ((size_t)2)
|
|
#define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1)
|
|
#define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2)
|
|
#define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
|
|
#define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U)
|
|
|
|
/* The bit mask value corresponding to MALLOC_ALIGNMENT */
|
|
#define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE)
|
|
|
|
/* True if address a has acceptable alignment */
|
|
#define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
|
|
|
|
/* the number of bytes to offset an address to align it */
|
|
#define align_offset(A)\
|
|
((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
|
|
((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
|
|
|
|
/* -------------------------- MMAP preliminaries ------------------------- */
|
|
|
|
/*
|
|
If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
|
|
checks to fail so compiler optimizer can delete code rather than
|
|
using so many "#if"s.
|
|
*/
|
|
|
|
|
|
/* MORECORE and MMAP must return MFAIL on failure */
|
|
#define MFAIL ((void*)(MAX_SIZE_T))
|
|
#define CMFAIL ((char*)(MFAIL)) /* defined for convenience */
|
|
|
|
#if !HAVE_MMAP
|
|
#else /* HAVE_MMAP */
|
|
#define IS_MMAPPED_BIT (SIZE_T_ONE)
|
|
#define USE_MMAP_BIT (SIZE_T_ONE)
|
|
|
|
#ifndef WIN32
|
|
|
|
#else /* WIN32 */
|
|
|
|
/* Win32 MMAP via VirtualAlloc */
|
|
static void* win32mmap(size_t size) {
|
|
void* ptr = KernelAlloc(size);
|
|
return (ptr != 0)? ptr: MFAIL;
|
|
}
|
|
|
|
/* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
|
|
static void* win32direct_mmap(size_t size) {
|
|
void* ptr = KernelAlloc(size);
|
|
return (ptr != 0)? ptr: MFAIL;
|
|
}
|
|
|
|
/* This function supports releasing coalesed segments */
|
|
static int win32munmap(void* ptr, size_t size) {
|
|
KernelFree(ptr);
|
|
return 0;
|
|
}
|
|
|
|
#define CALL_MMAP(s) win32mmap(s)
|
|
#define CALL_MUNMAP(a, s) win32munmap((a), (s))
|
|
#define DIRECT_MMAP(s) win32direct_mmap(s)
|
|
#endif /* WIN32 */
|
|
#endif /* HAVE_MMAP */
|
|
|
|
#if HAVE_MMAP && HAVE_MREMAP
|
|
#else /* HAVE_MMAP && HAVE_MREMAP */
|
|
#define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
|
|
#endif /* HAVE_MMAP && HAVE_MREMAP */
|
|
|
|
#if HAVE_MORECORE
|
|
#else /* HAVE_MORECORE */
|
|
#define CALL_MORECORE(S) MFAIL
|
|
#endif /* HAVE_MORECORE */
|
|
|
|
/* mstate bit set if continguous morecore disabled or failed */
|
|
#define USE_NONCONTIGUOUS_BIT (4U)
|
|
|
|
/* segment bit set in create_mspace_with_base */
|
|
#define EXTERN_BIT (8U)
|
|
|
|
|
|
/* --------------------------- Lock preliminaries ------------------------ */
|
|
|
|
#if USE_LOCKS
|
|
#else /* USE_LOCKS */
|
|
#define USE_LOCK_BIT (0U)
|
|
#define INITIAL_LOCK(l)
|
|
#endif /* USE_LOCKS */
|
|
|
|
#if USE_LOCKS && HAVE_MORECORE
|
|
#define ACQUIRE_MORECORE_LOCK() ACQUIRE_LOCK(&morecore_mutex);
|
|
#define RELEASE_MORECORE_LOCK() RELEASE_LOCK(&morecore_mutex);
|
|
#else /* USE_LOCKS && HAVE_MORECORE */
|
|
#define ACQUIRE_MORECORE_LOCK()
|
|
#define RELEASE_MORECORE_LOCK()
|
|
#endif /* USE_LOCKS && HAVE_MORECORE */
|
|
|
|
#if USE_LOCKS
|
|
#define ACQUIRE_MAGIC_INIT_LOCK() ACQUIRE_LOCK(&magic_init_mutex);
|
|
#define RELEASE_MAGIC_INIT_LOCK() RELEASE_LOCK(&magic_init_mutex);
|
|
#else /* USE_LOCKS */
|
|
#define ACQUIRE_MAGIC_INIT_LOCK()
|
|
#define RELEASE_MAGIC_INIT_LOCK()
|
|
#endif /* USE_LOCKS */
|
|
|
|
|
|
/* ----------------------- Chunk representations ------------------------ */
|
|
|
|
/*
|
|
(The following includes lightly edited explanations by Colin Plumb.)
|
|
|
|
The malloc_chunk declaration below is misleading (but accurate and
|
|
necessary). It declares a "view" into memory allowing access to
|
|
necessary fields at known offsets from a given base.
|
|
|
|
Chunks of memory are maintained using a `boundary tag' method as
|
|
originally described by Knuth. (See the paper by Paul Wilson
|
|
ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
|
|
techniques.) Sizes of free chunks are stored both in the front of
|
|
each chunk and at the end. This makes consolidating fragmented
|
|
chunks into bigger chunks fast. The head fields also hold bits
|
|
representing whether chunks are free or in use.
|
|
|
|
Here are some pictures to make it clearer. They are "exploded" to
|
|
show that the state of a chunk can be thought of as extending from
|
|
the high 31 bits of the head field of its header through the
|
|
prev_foot and PINUSE_BIT bit of the following chunk header.
|
|
|
|
A chunk that's in use looks like:
|
|
|
|
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Size of previous chunk (if P = 1) |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
|
|
| Size of this chunk 1| +-+
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| |
|
|
+- -+
|
|
| |
|
|
+- -+
|
|
| :
|
|
+- size - sizeof(size_t) available payload bytes -+
|
|
: |
|
|
chunk-> +- -+
|
|
| |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
|
|
| Size of next chunk (may or may not be in use) | +-+
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|
|
And if it's free, it looks like this:
|
|
|
|
chunk-> +- -+
|
|
| User payload (must be in use, or we would have merged!) |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
|
|
| Size of this chunk 0| +-+
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Next pointer |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Prev pointer |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| :
|
|
+- size - sizeof(struct chunk) unused bytes -+
|
|
: |
|
|
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Size of this chunk |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
|
|
| Size of next chunk (must be in use, or we would have merged)| +-+
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| :
|
|
+- User payload -+
|
|
: |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|0|
|
|
+-+
|
|
Note that since we always merge adjacent free chunks, the chunks
|
|
adjacent to a free chunk must be in use.
|
|
|
|
Given a pointer to a chunk (which can be derived trivially from the
|
|
payload pointer) we can, in O(1) time, find out whether the adjacent
|
|
chunks are free, and if so, unlink them from the lists that they
|
|
are on and merge them with the current chunk.
|
|
|
|
Chunks always begin on even word boundaries, so the mem portion
|
|
(which is returned to the user) is also on an even word boundary, and
|
|
thus at least double-word aligned.
|
|
|
|
The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
|
|
chunk size (which is always a multiple of two words), is an in-use
|
|
bit for the *previous* chunk. If that bit is *clear*, then the
|
|
word before the current chunk size contains the previous chunk
|
|
size, and can be used to find the front of the previous chunk.
|
|
The very first chunk allocated always has this bit set, preventing
|
|
access to non-existent (or non-owned) memory. If pinuse is set for
|
|
any given chunk, then you CANNOT determine the size of the
|
|
previous chunk, and might even get a memory addressing fault when
|
|
trying to do so.
|
|
|
|
The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
|
|
the chunk size redundantly records whether the current chunk is
|
|
inuse. This redundancy enables usage checks within free and realloc,
|
|
and reduces indirection when freeing and consolidating chunks.
|
|
|
|
Each freshly allocated chunk must have both cinuse and pinuse set.
|
|
That is, each allocated chunk borders either a previously allocated
|
|
and still in-use chunk, or the base of its memory arena. This is
|
|
ensured by making all allocations from the the `lowest' part of any
|
|
found chunk. Further, no free chunk physically borders another one,
|
|
so each free chunk is known to be preceded and followed by either
|
|
inuse chunks or the ends of memory.
|
|
|
|
Note that the `foot' of the current chunk is actually represented
|
|
as the prev_foot of the NEXT chunk. This makes it easier to
|
|
deal with alignments etc but can be very confusing when trying
|
|
to extend or adapt this code.
|
|
|
|
The exceptions to all this are
|
|
|
|
1. The special chunk `top' is the top-most available chunk (i.e.,
|
|
the one bordering the end of available memory). It is treated
|
|
specially. Top is never included in any bin, is used only if
|
|
no other chunk is available, and is released back to the
|
|
system if it is very large (see M_TRIM_THRESHOLD). In effect,
|
|
the top chunk is treated as larger (and thus less well
|
|
fitting) than any other available chunk. The top chunk
|
|
doesn't update its trailing size field since there is no next
|
|
contiguous chunk that would have to index off it. However,
|
|
space is still allocated for it (TOP_FOOT_SIZE) to enable
|
|
separation or merging when space is extended.
|
|
|
|
3. Chunks allocated via mmap, which have the lowest-order bit
|
|
(IS_MMAPPED_BIT) set in their prev_foot fields, and do not set
|
|
PINUSE_BIT in their head fields. Because they are allocated
|
|
one-by-one, each must carry its own prev_foot field, which is
|
|
also used to hold the offset this chunk has within its mmapped
|
|
region, which is needed to preserve alignment. Each mmapped
|
|
chunk is trailed by the first two fields of a fake next-chunk
|
|
for sake of usage checks.
|
|
|
|
*/
|
|
|
|
struct malloc_chunk {
|
|
size_t prev_foot; /* Size of previous chunk (if free). */
|
|
size_t head; /* Size and inuse bits. */
|
|
struct malloc_chunk* fd; /* double links -- used only if free. */
|
|
struct malloc_chunk* bk;
|
|
};
|
|
|
|
typedef struct malloc_chunk mchunk;
|
|
typedef struct malloc_chunk* mchunkptr;
|
|
typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
|
|
typedef unsigned int bindex_t; /* Described below */
|
|
typedef unsigned int binmap_t; /* Described below */
|
|
typedef unsigned int flag_t; /* The type of various bit flag sets */
|
|
|
|
/* ------------------- Chunks sizes and alignments ----------------------- */
|
|
|
|
#define MCHUNK_SIZE (sizeof(mchunk))
|
|
|
|
#if FOOTERS
|
|
#define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
|
|
#else /* FOOTERS */
|
|
#define CHUNK_OVERHEAD (SIZE_T_SIZE)
|
|
#endif /* FOOTERS */
|
|
|
|
/* MMapped chunks need a second word of overhead ... */
|
|
#define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
|
|
/* ... and additional padding for fake next-chunk at foot */
|
|
#define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES)
|
|
|
|
/* The smallest size we can malloc is an aligned minimal chunk */
|
|
#define MIN_CHUNK_SIZE\
|
|
((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
|
|
|
|
/* conversion from malloc headers to user pointers, and back */
|
|
#define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES))
|
|
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
|
|
/* chunk associated with aligned address A */
|
|
#define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A)))
|
|
|
|
/* Bounds on request (not chunk) sizes. */
|
|
#define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2)
|
|
#define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
|
|
|
|
/* pad request bytes into a usable size */
|
|
#define pad_request(req) \
|
|
(((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
|
|
|
|
/* pad request, checking for minimum (but not maximum) */
|
|
#define request2size(req) \
|
|
(((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
|
|
|
|
|
|
/* ------------------ Operations on head and foot fields ----------------- */
|
|
|
|
/*
|
|
The head field of a chunk is or'ed with PINUSE_BIT when previous
|
|
adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
|
|
use. If the chunk was obtained with mmap, the prev_foot field has
|
|
IS_MMAPPED_BIT set, otherwise holding the offset of the base of the
|
|
mmapped region to the base of the chunk.
|
|
*/
|
|
|
|
#define PINUSE_BIT (SIZE_T_ONE)
|
|
#define CINUSE_BIT (SIZE_T_TWO)
|
|
#define INUSE_BITS (PINUSE_BIT|CINUSE_BIT)
|
|
|
|
/* Head value for fenceposts */
|
|
#define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE)
|
|
|
|
/* extraction of fields from head words */
|
|
#define cinuse(p) ((p)->head & CINUSE_BIT)
|
|
#define pinuse(p) ((p)->head & PINUSE_BIT)
|
|
#define chunksize(p) ((p)->head & ~(INUSE_BITS))
|
|
|
|
#define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT)
|
|
#define clear_cinuse(p) ((p)->head &= ~CINUSE_BIT)
|
|
|
|
/* Treat space at ptr +/- offset as a chunk */
|
|
#define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
|
|
#define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
|
|
|
|
/* Ptr to next or previous physical malloc_chunk. */
|
|
#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~INUSE_BITS)))
|
|
#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
|
|
|
|
/* extract next chunk's pinuse bit */
|
|
#define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT)
|
|
|
|
/* Get/set size at footer */
|
|
#define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot)
|
|
#define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
|
|
|
|
/* Set size, pinuse bit, and foot */
|
|
#define set_size_and_pinuse_of_free_chunk(p, s)\
|
|
((p)->head = (s|PINUSE_BIT), set_foot(p, s))
|
|
|
|
/* Set size, pinuse bit, foot, and clear next pinuse */
|
|
#define set_free_with_pinuse(p, s, n)\
|
|
(clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
|
|
|
|
#define is_mmapped(p)\
|
|
(!((p)->head & PINUSE_BIT) && ((p)->prev_foot & IS_MMAPPED_BIT))
|
|
|
|
/* Get the internal overhead associated with chunk p */
|
|
#define overhead_for(p)\
|
|
(is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
|
|
|
|
/* Return true if malloced space is not necessarily cleared */
|
|
#if MMAP_CLEARS
|
|
#define calloc_must_clear(p) (!is_mmapped(p))
|
|
#else /* MMAP_CLEARS */
|
|
#define calloc_must_clear(p) (1)
|
|
#endif /* MMAP_CLEARS */
|
|
|
|
/* ---------------------- Overlaid data structures ----------------------- */
|
|
|
|
/*
|
|
When chunks are not in use, they are treated as nodes of either
|
|
lists or trees.
|
|
|
|
"Small" chunks are stored in circular doubly-linked lists, and look
|
|
like this:
|
|
|
|
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Size of previous chunk |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
`head:' | Size of chunk, in bytes |P|
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Forward pointer to next chunk in list |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Back pointer to previous chunk in list |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Unused space (may be 0 bytes long) .
|
|
. .
|
|
. |
|
|
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
`foot:' | Size of chunk, in bytes |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|
|
Larger chunks are kept in a form of bitwise digital trees (aka
|
|
tries) keyed on chunksizes. Because malloc_tree_chunks are only for
|
|
free chunks greater than 256 bytes, their size doesn't impose any
|
|
constraints on user chunk sizes. Each node looks like:
|
|
|
|
chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Size of previous chunk |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
`head:' | Size of chunk, in bytes |P|
|
|
mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Forward pointer to next chunk of same size |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Back pointer to previous chunk of same size |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Pointer to left child (child[0]) |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Pointer to right child (child[1]) |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Pointer to parent |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| bin index of this chunk |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Unused space .
|
|
. |
|
|
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
`foot:' | Size of chunk, in bytes |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|
|
Each tree holding treenodes is a tree of unique chunk sizes. Chunks
|
|
of the same size are arranged in a circularly-linked list, with only
|
|
the oldest chunk (the next to be used, in our FIFO ordering)
|
|
actually in the tree. (Tree members are distinguished by a non-null
|
|
parent pointer.) If a chunk with the same size an an existing node
|
|
is inserted, it is linked off the existing node using pointers that
|
|
work in the same way as fd/bk pointers of small chunks.
|
|
|
|
Each tree contains a power of 2 sized range of chunk sizes (the
|
|
smallest is 0x100 <= x < 0x180), which is is divided in half at each
|
|
tree level, with the chunks in the smaller half of the range (0x100
|
|
<= x < 0x140 for the top nose) in the left subtree and the larger
|
|
half (0x140 <= x < 0x180) in the right subtree. This is, of course,
|
|
done by inspecting individual bits.
|
|
|
|
Using these rules, each node's left subtree contains all smaller
|
|
sizes than its right subtree. However, the node at the root of each
|
|
subtree has no particular ordering relationship to either. (The
|
|
dividing line between the subtree sizes is based on trie relation.)
|
|
If we remove the last chunk of a given size from the interior of the
|
|
tree, we need to replace it with a leaf node. The tree ordering
|
|
rules permit a node to be replaced by any leaf below it.
|
|
|
|
The smallest chunk in a tree (a common operation in a best-fit
|
|
allocator) can be found by walking a path to the leftmost leaf in
|
|
the tree. Unlike a usual binary tree, where we follow left child
|
|
pointers until we reach a null, here we follow the right child
|
|
pointer any time the left one is null, until we reach a leaf with
|
|
both child pointers null. The smallest chunk in the tree will be
|
|
somewhere along that path.
|
|
|
|
The worst case number of steps to add, find, or remove a node is
|
|
bounded by the number of bits differentiating chunks within
|
|
bins. Under current bin calculations, this ranges from 6 up to 21
|
|
(for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
|
|
is of course much better.
|
|
*/
|
|
|
|
struct malloc_tree_chunk {
|
|
/* The first four fields must be compatible with malloc_chunk */
|
|
size_t prev_foot;
|
|
size_t head;
|
|
struct malloc_tree_chunk* fd;
|
|
struct malloc_tree_chunk* bk;
|
|
|
|
struct malloc_tree_chunk* child[2];
|
|
struct malloc_tree_chunk* parent;
|
|
bindex_t index;
|
|
};
|
|
|
|
typedef struct malloc_tree_chunk tchunk;
|
|
typedef struct malloc_tree_chunk* tchunkptr;
|
|
typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
|
|
|
|
/* A little helper macro for trees */
|
|
#define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
|
|
|
|
/* ----------------------------- Segments -------------------------------- */
|
|
|
|
/*
|
|
Each malloc space may include non-contiguous segments, held in a
|
|
list headed by an embedded malloc_segment record representing the
|
|
top-most space. Segments also include flags holding properties of
|
|
the space. Large chunks that are directly allocated by mmap are not
|
|
included in this list. They are instead independently created and
|
|
destroyed without otherwise keeping track of them.
|
|
|
|
Segment management mainly comes into play for spaces allocated by
|
|
MMAP. Any call to MMAP might or might not return memory that is
|
|
adjacent to an existing segment. MORECORE normally contiguously
|
|
extends the current space, so this space is almost always adjacent,
|
|
which is simpler and faster to deal with. (This is why MORECORE is
|
|
used preferentially to MMAP when both are available -- see
|
|
sys_alloc.) When allocating using MMAP, we don't use any of the
|
|
hinting mechanisms (inconsistently) supported in various
|
|
implementations of unix mmap, or distinguish reserving from
|
|
committing memory. Instead, we just ask for space, and exploit
|
|
contiguity when we get it. It is probably possible to do
|
|
better than this on some systems, but no general scheme seems
|
|
to be significantly better.
|
|
|
|
Management entails a simpler variant of the consolidation scheme
|
|
used for chunks to reduce fragmentation -- new adjacent memory is
|
|
normally prepended or appended to an existing segment. However,
|
|
there are limitations compared to chunk consolidation that mostly
|
|
reflect the fact that segment processing is relatively infrequent
|
|
(occurring only when getting memory from system) and that we
|
|
don't expect to have huge numbers of segments:
|
|
|
|
* Segments are not indexed, so traversal requires linear scans. (It
|
|
would be possible to index these, but is not worth the extra
|
|
overhead and complexity for most programs on most platforms.)
|
|
* New segments are only appended to old ones when holding top-most
|
|
memory; if they cannot be prepended to others, they are held in
|
|
different segments.
|
|
|
|
Except for the top-most segment of an mstate, each segment record
|
|
is kept at the tail of its segment. Segments are added by pushing
|
|
segment records onto the list headed by &mstate.seg for the
|
|
containing mstate.
|
|
|
|
Segment flags control allocation/merge/deallocation policies:
|
|
* If EXTERN_BIT set, then we did not allocate this segment,
|
|
and so should not try to deallocate or merge with others.
|
|
(This currently holds only for the initial segment passed
|
|
into create_mspace_with_base.)
|
|
* If IS_MMAPPED_BIT set, the segment may be merged with
|
|
other surrounding mmapped segments and trimmed/de-allocated
|
|
using munmap.
|
|
* If neither bit is set, then the segment was obtained using
|
|
MORECORE so can be merged with surrounding MORECORE'd segments
|
|
and deallocated/trimmed using MORECORE with negative arguments.
|
|
*/
|
|
|
|
struct malloc_segment {
|
|
char* base; /* base address */
|
|
size_t size; /* allocated size */
|
|
struct malloc_segment* next; /* ptr to next segment */
|
|
flag_t sflags; /* mmap and extern flag */
|
|
};
|
|
|
|
#define is_mmapped_segment(S) ((S)->sflags & IS_MMAPPED_BIT)
|
|
#define is_extern_segment(S) ((S)->sflags & EXTERN_BIT)
|
|
|
|
typedef struct malloc_segment msegment;
|
|
typedef struct malloc_segment* msegmentptr;
|
|
|
|
/* ---------------------------- malloc_state ----------------------------- */
|
|
|
|
/*
|
|
A malloc_state holds all of the bookkeeping for a space.
|
|
The main fields are:
|
|
|
|
Top
|
|
The topmost chunk of the currently active segment. Its size is
|
|
cached in topsize. The actual size of topmost space is
|
|
topsize+TOP_FOOT_SIZE, which includes space reserved for adding
|
|
fenceposts and segment records if necessary when getting more
|
|
space from the system. The size at which to autotrim top is
|
|
cached from mparams in trim_check, except that it is disabled if
|
|
an autotrim fails.
|
|
|
|
Designated victim (dv)
|
|
This is the preferred chunk for servicing small requests that
|
|
don't have exact fits. It is normally the chunk split off most
|
|
recently to service another small request. Its size is cached in
|
|
dvsize. The link fields of this chunk are not maintained since it
|
|
is not kept in a bin.
|
|
|
|
SmallBins
|
|
An array of bin headers for free chunks. These bins hold chunks
|
|
with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
|
|
chunks of all the same size, spaced 8 bytes apart. To simplify
|
|
use in double-linked lists, each bin header acts as a malloc_chunk
|
|
pointing to the real first node, if it exists (else pointing to
|
|
itself). This avoids special-casing for headers. But to avoid
|
|
waste, we allocate only the fd/bk pointers of bins, and then use
|
|
repositioning tricks to treat these as the fields of a chunk.
|
|
|
|
TreeBins
|
|
Treebins are pointers to the roots of trees holding a range of
|
|
sizes. There are 2 equally spaced treebins for each power of two
|
|
from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
|
|
larger.
|
|
|
|
Bin maps
|
|
There is one bit map for small bins ("smallmap") and one for
|
|
treebins ("treemap). Each bin sets its bit when non-empty, and
|
|
clears the bit when empty. Bit operations are then used to avoid
|
|
bin-by-bin searching -- nearly all "search" is done without ever
|
|
looking at bins that won't be selected. The bit maps
|
|
conservatively use 32 bits per map word, even if on 64bit system.
|
|
For a good description of some of the bit-based techniques used
|
|
here, see Henry S. Warren Jr's book "Hacker's Delight" (and
|
|
supplement at http://hackersdelight.org/). Many of these are
|
|
intended to reduce the branchiness of paths through malloc etc, as
|
|
well as to reduce the number of memory locations read or written.
|
|
|
|
Segments
|
|
A list of segments headed by an embedded malloc_segment record
|
|
representing the initial space.
|
|
|
|
Address check support
|
|
The least_addr field is the least address ever obtained from
|
|
MORECORE or MMAP. Attempted frees and reallocs of any address less
|
|
than this are trapped (unless INSECURE is defined).
|
|
|
|
Magic tag
|
|
A cross-check field that should always hold same value as mparams.magic.
|
|
|
|
Flags
|
|
Bits recording whether to use MMAP, locks, or contiguous MORECORE
|
|
|
|
Statistics
|
|
Each space keeps track of current and maximum system memory
|
|
obtained via MORECORE or MMAP.
|
|
|
|
Locking
|
|
If USE_LOCKS is defined, the "mutex" lock is acquired and released
|
|
around every public call using this mspace.
|
|
*/
|
|
|
|
/* Bin types, widths and sizes */
|
|
#define NSMALLBINS (32U)
|
|
#define NTREEBINS (32U)
|
|
#define SMALLBIN_SHIFT (3U)
|
|
#define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT)
|
|
#define TREEBIN_SHIFT (8U)
|
|
#define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT)
|
|
#define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE)
|
|
#define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
|
|
|
|
struct malloc_state {
|
|
binmap_t smallmap;
|
|
binmap_t treemap;
|
|
size_t dvsize;
|
|
size_t topsize;
|
|
char* least_addr;
|
|
mchunkptr dv;
|
|
mchunkptr top;
|
|
size_t trim_check;
|
|
size_t magic;
|
|
mchunkptr smallbins[(NSMALLBINS+1)*2];
|
|
tbinptr treebins[NTREEBINS];
|
|
size_t footprint;
|
|
size_t max_footprint;
|
|
flag_t mflags;
|
|
#if USE_LOCKS
|
|
MLOCK_T mutex; /* locate lock among fields that rarely change */
|
|
#endif /* USE_LOCKS */
|
|
msegment seg;
|
|
};
|
|
|
|
typedef struct malloc_state* mstate;
|
|
|
|
/* ------------- Global malloc_state and malloc_params ------------------- */
|
|
|
|
/*
|
|
malloc_params holds global properties, including those that can be
|
|
dynamically set using mallopt. There is a single instance, mparams,
|
|
initialized in init_mparams.
|
|
*/
|
|
|
|
struct malloc_params {
|
|
size_t magic;
|
|
size_t page_size;
|
|
size_t granularity;
|
|
size_t mmap_threshold;
|
|
size_t trim_threshold;
|
|
flag_t default_mflags;
|
|
};
|
|
|
|
static struct malloc_params mparams;
|
|
|
|
/* The global malloc_state used for all non-"mspace" calls */
|
|
static struct malloc_state _gm_;
|
|
#define gm (&_gm_)
|
|
#define is_global(M) ((M) == &_gm_)
|
|
#define is_initialized(M) ((M)->top != 0)
|
|
|
|
/* -------------------------- system alloc setup ------------------------- */
|
|
|
|
/* Operations on mflags */
|
|
|
|
#define use_lock(M) ((M)->mflags & USE_LOCK_BIT)
|
|
#define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT)
|
|
#define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT)
|
|
|
|
#define use_mmap(M) ((M)->mflags & USE_MMAP_BIT)
|
|
#define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT)
|
|
#define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT)
|
|
|
|
#define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT)
|
|
#define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT)
|
|
|
|
#define set_lock(M,L)\
|
|
((M)->mflags = (L)?\
|
|
((M)->mflags | USE_LOCK_BIT) :\
|
|
((M)->mflags & ~USE_LOCK_BIT))
|
|
|
|
/* page-align a size */
|
|
#define page_align(S)\
|
|
(((S) + (mparams.page_size)) & ~(mparams.page_size - SIZE_T_ONE))
|
|
|
|
/* granularity-align a size */
|
|
#define granularity_align(S)\
|
|
(((S) + (mparams.granularity)) & ~(mparams.granularity - SIZE_T_ONE))
|
|
|
|
#define is_page_aligned(S)\
|
|
(((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
|
|
#define is_granularity_aligned(S)\
|
|
(((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
|
|
|
|
/* True if segment S holds address A */
|
|
#define segment_holds(S, A)\
|
|
((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
|
|
|
|
/* Return segment holding given address */
|
|
static msegmentptr segment_holding(mstate m, char* addr) {
|
|
msegmentptr sp = &m->seg;
|
|
for (;;) {
|
|
if (addr >= sp->base && addr < sp->base + sp->size)
|
|
return sp;
|
|
if ((sp = sp->next) == 0)
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* Return true if segment contains a segment link */
|
|
static int has_segment_link(mstate m, msegmentptr ss) {
|
|
msegmentptr sp = &m->seg;
|
|
for (;;) {
|
|
if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
|
|
return 1;
|
|
if ((sp = sp->next) == 0)
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
#ifndef MORECORE_CANNOT_TRIM
|
|
#define should_trim(M,s) ((s) > (M)->trim_check)
|
|
#else /* MORECORE_CANNOT_TRIM */
|
|
#define should_trim(M,s) (0)
|
|
#endif /* MORECORE_CANNOT_TRIM */
|
|
|
|
/*
|
|
TOP_FOOT_SIZE is padding at the end of a segment, including space
|
|
that may be needed to place segment records and fenceposts when new
|
|
noncontiguous segments are added.
|
|
*/
|
|
#define TOP_FOOT_SIZE\
|
|
(align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
|
|
|
|
|
|
/* ------------------------------- Hooks -------------------------------- */
|
|
|
|
/*
|
|
PREACTION should be defined to return 0 on success, and nonzero on
|
|
failure. If you are not using locking, you can redefine these to do
|
|
anything you like.
|
|
*/
|
|
|
|
#if USE_LOCKS
|
|
|
|
/* Ensure locks are initialized */
|
|
#define GLOBALLY_INITIALIZE() (mparams.page_size == 0 && init_mparams())
|
|
|
|
#define PREACTION(M) ((GLOBALLY_INITIALIZE() || use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
|
|
#define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
|
|
#else /* USE_LOCKS */
|
|
|
|
#ifndef PREACTION
|
|
#define PREACTION(M) (0)
|
|
#endif /* PREACTION */
|
|
|
|
#ifndef POSTACTION
|
|
#define POSTACTION(M)
|
|
#endif /* POSTACTION */
|
|
|
|
#endif /* USE_LOCKS */
|
|
|
|
/*
|
|
CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
|
|
USAGE_ERROR_ACTION is triggered on detected bad frees and
|
|
reallocs. The argument p is an address that might have triggered the
|
|
fault. It is ignored by the two predefined actions, but might be
|
|
useful in custom actions that try to help diagnose errors.
|
|
*/
|
|
|
|
#if PROCEED_ON_ERROR
|
|
|
|
/* A count of the number of corruption errors causing resets */
|
|
int malloc_corruption_error_count;
|
|
|
|
/* default corruption action */
|
|
static void reset_on_error(mstate m);
|
|
|
|
#define CORRUPTION_ERROR_ACTION(m) reset_on_error(m)
|
|
#define USAGE_ERROR_ACTION(m, p)
|
|
|
|
#else /* PROCEED_ON_ERROR */
|
|
|
|
#ifndef CORRUPTION_ERROR_ACTION
|
|
#define CORRUPTION_ERROR_ACTION(m) ABORT
|
|
#endif /* CORRUPTION_ERROR_ACTION */
|
|
|
|
#ifndef USAGE_ERROR_ACTION
|
|
#define USAGE_ERROR_ACTION(m,p) ABORT
|
|
#endif /* USAGE_ERROR_ACTION */
|
|
|
|
#endif /* PROCEED_ON_ERROR */
|
|
|
|
/* -------------------------- Debugging setup ---------------------------- */
|
|
|
|
#if ! DEBUG
|
|
|
|
#define check_free_chunk(M,P)
|
|
#define check_inuse_chunk(M,P)
|
|
#define check_malloced_chunk(M,P,N)
|
|
#define check_mmapped_chunk(M,P)
|
|
#define check_malloc_state(M)
|
|
#define check_top_chunk(M,P)
|
|
|
|
#else /* DEBUG */
|
|
#define check_free_chunk(M,P) do_check_free_chunk(M,P)
|
|
#define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P)
|
|
#define check_top_chunk(M,P) do_check_top_chunk(M,P)
|
|
#define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
|
|
#define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P)
|
|
#define check_malloc_state(M) do_check_malloc_state(M)
|
|
|
|
static void do_check_any_chunk(mstate m, mchunkptr p);
|
|
static void do_check_top_chunk(mstate m, mchunkptr p);
|
|
static void do_check_mmapped_chunk(mstate m, mchunkptr p);
|
|
static void do_check_inuse_chunk(mstate m, mchunkptr p);
|
|
static void do_check_free_chunk(mstate m, mchunkptr p);
|
|
static void do_check_malloced_chunk(mstate m, void* mem, size_t s);
|
|
static void do_check_tree(mstate m, tchunkptr t);
|
|
static void do_check_treebin(mstate m, bindex_t i);
|
|
static void do_check_smallbin(mstate m, bindex_t i);
|
|
static void do_check_malloc_state(mstate m);
|
|
static int bin_find(mstate m, mchunkptr x);
|
|
static size_t traverse_and_check(mstate m);
|
|
#endif /* DEBUG */
|
|
|
|
/* ---------------------------- Indexing Bins ---------------------------- */
|
|
|
|
#define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
|
|
#define small_index(s) ((s) >> SMALLBIN_SHIFT)
|
|
#define small_index2size(i) ((i) << SMALLBIN_SHIFT)
|
|
#define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE))
|
|
|
|
/* addressing by index. See above about smallbin repositioning */
|
|
#define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
|
|
#define treebin_at(M,i) (&((M)->treebins[i]))
|
|
|
|
/* assign tree index for size S to variable I */
|
|
#if defined(__GNUC__) && defined(i386)
|
|
#define compute_tree_index(S, I)\
|
|
{\
|
|
size_t X = S >> TREEBIN_SHIFT;\
|
|
if (X == 0)\
|
|
I = 0;\
|
|
else if (X > 0xFFFF)\
|
|
I = NTREEBINS-1;\
|
|
else {\
|
|
unsigned int K;\
|
|
__asm__("bsrl %1,%0\n\t" : "=r" (K) : "rm" (X));\
|
|
I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
|
|
}\
|
|
}
|
|
#else /* GNUC */
|
|
#define compute_tree_index(S, I)\
|
|
{\
|
|
size_t X = S >> TREEBIN_SHIFT;\
|
|
if (X == 0)\
|
|
I = 0;\
|
|
else if (X > 0xFFFF)\
|
|
I = NTREEBINS-1;\
|
|
else {\
|
|
unsigned int Y = (unsigned int)X;\
|
|
unsigned int N = ((Y - 0x100) >> 16) & 8;\
|
|
unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
|
|
N += K;\
|
|
N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
|
|
K = 14 - N + ((Y <<= K) >> 15);\
|
|
I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
|
|
}\
|
|
}
|
|
#endif /* GNUC */
|
|
|
|
/* Bit representing maximum resolved size in a treebin at i */
|
|
#define bit_for_tree_index(i) \
|
|
(i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
|
|
|
|
/* Shift placing maximum resolved bit in a treebin at i as sign bit */
|
|
#define leftshift_for_tree_index(i) \
|
|
((i == NTREEBINS-1)? 0 : \
|
|
((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
|
|
|
|
/* The size of the smallest chunk held in bin with index i */
|
|
#define minsize_for_tree_index(i) \
|
|
((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \
|
|
(((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
|
|
|
|
|
|
/* ------------------------ Operations on bin maps ----------------------- */
|
|
|
|
/* bit corresponding to given index */
|
|
#define idx2bit(i) ((binmap_t)(1) << (i))
|
|
|
|
/* Mark/Clear bits with given index */
|
|
#define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i))
|
|
#define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i))
|
|
#define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i))
|
|
|
|
#define mark_treemap(M,i) ((M)->treemap |= idx2bit(i))
|
|
#define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i))
|
|
#define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i))
|
|
|
|
/* index corresponding to given bit */
|
|
|
|
#if defined(__GNUC__) && defined(i386)
|
|
#define compute_bit2idx(X, I)\
|
|
{\
|
|
unsigned int J;\
|
|
__asm__("bsfl %1,%0\n\t" : "=r" (J) : "rm" (X));\
|
|
I = (bindex_t)J;\
|
|
}
|
|
|
|
#else /* GNUC */
|
|
#if USE_BUILTIN_FFS
|
|
#define compute_bit2idx(X, I) I = ffs(X)-1
|
|
|
|
#else /* USE_BUILTIN_FFS */
|
|
#define compute_bit2idx(X, I)\
|
|
{\
|
|
unsigned int Y = X - 1;\
|
|
unsigned int K = Y >> (16-4) & 16;\
|
|
unsigned int N = K; Y >>= K;\
|
|
N += K = Y >> (8-3) & 8; Y >>= K;\
|
|
N += K = Y >> (4-2) & 4; Y >>= K;\
|
|
N += K = Y >> (2-1) & 2; Y >>= K;\
|
|
N += K = Y >> (1-0) & 1; Y >>= K;\
|
|
I = (bindex_t)(N + Y);\
|
|
}
|
|
#endif /* USE_BUILTIN_FFS */
|
|
#endif /* GNUC */
|
|
|
|
/* isolate the least set bit of a bitmap */
|
|
#define least_bit(x) ((x) & -(x))
|
|
|
|
/* mask with all bits to left of least bit of x on */
|
|
#define left_bits(x) ((x<<1) | -(x<<1))
|
|
|
|
/* mask with all bits to left of or equal to least bit of x on */
|
|
#define same_or_left_bits(x) ((x) | -(x))
|
|
|
|
|
|
/* ----------------------- Runtime Check Support ------------------------- */
|
|
|
|
/*
|
|
For security, the main invariant is that malloc/free/etc never
|
|
writes to a static address other than malloc_state, unless static
|
|
malloc_state itself has been corrupted, which cannot occur via
|
|
malloc (because of these checks). In essence this means that we
|
|
believe all pointers, sizes, maps etc held in malloc_state, but
|
|
check all of those linked or offsetted from other embedded data
|
|
structures. These checks are interspersed with main code in a way
|
|
that tends to minimize their run-time cost.
|
|
|
|
When FOOTERS is defined, in addition to range checking, we also
|
|
verify footer fields of inuse chunks, which can be used guarantee
|
|
that the mstate controlling malloc/free is intact. This is a
|
|
streamlined version of the approach described by William Robertson
|
|
et al in "Run-time Detection of Heap-based Overflows" LISA'03
|
|
http://www.usenix.org/events/lisa03/tech/robertson.html The footer
|
|
of an inuse chunk holds the xor of its mstate and a random seed,
|
|
that is checked upon calls to free() and realloc(). This is
|
|
(probablistically) unguessable from outside the program, but can be
|
|
computed by any code successfully malloc'ing any chunk, so does not
|
|
itself provide protection against code that has already broken
|
|
security through some other means. Unlike Robertson et al, we
|
|
always dynamically check addresses of all offset chunks (previous,
|
|
next, etc). This turns out to be cheaper than relying on hashes.
|
|
*/
|
|
|
|
#if !INSECURE
|
|
/* Check if address a is at least as high as any from MORECORE or MMAP */
|
|
#define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
|
|
/* Check if address of next chunk n is higher than base chunk p */
|
|
#define ok_next(p, n) ((char*)(p) < (char*)(n))
|
|
/* Check if p has its cinuse bit on */
|
|
#define ok_cinuse(p) cinuse(p)
|
|
/* Check if p has its pinuse bit on */
|
|
#define ok_pinuse(p) pinuse(p)
|
|
|
|
#else /* !INSECURE */
|
|
#define ok_address(M, a) (1)
|
|
#define ok_next(b, n) (1)
|
|
#define ok_cinuse(p) (1)
|
|
#define ok_pinuse(p) (1)
|
|
#endif /* !INSECURE */
|
|
|
|
#if (FOOTERS && !INSECURE)
|
|
/* Check if (alleged) mstate m has expected magic field */
|
|
#define ok_magic(M) ((M)->magic == mparams.magic)
|
|
#else /* (FOOTERS && !INSECURE) */
|
|
#define ok_magic(M) (1)
|
|
#endif /* (FOOTERS && !INSECURE) */
|
|
|
|
|
|
/* In gcc, use __builtin_expect to minimize impact of checks */
|
|
#if !INSECURE
|
|
#if defined(__GNUC__) && __GNUC__ >= 3
|
|
#define RTCHECK(e) __builtin_expect(e, 1)
|
|
#else /* GNUC */
|
|
#define RTCHECK(e) (e)
|
|
#endif /* GNUC */
|
|
#else /* !INSECURE */
|
|
#define RTCHECK(e) (1)
|
|
#endif /* !INSECURE */
|
|
|
|
/* macros to set up inuse chunks with or without footers */
|
|
|
|
#if !FOOTERS
|
|
|
|
#define mark_inuse_foot(M,p,s)
|
|
|
|
/* Set cinuse bit and pinuse bit of next chunk */
|
|
#define set_inuse(M,p,s)\
|
|
((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
|
|
((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
|
|
|
|
/* Set cinuse and pinuse of this chunk and pinuse of next chunk */
|
|
#define set_inuse_and_pinuse(M,p,s)\
|
|
((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
|
|
((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
|
|
|
|
/* Set size, cinuse and pinuse bit of this chunk */
|
|
#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
|
|
((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
|
|
|
|
#else /* FOOTERS */
|
|
|
|
/* Set foot of inuse chunk to be xor of mstate and seed */
|
|
#define mark_inuse_foot(M,p,s)\
|
|
(((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
|
|
|
|
#define get_mstate_for(p)\
|
|
((mstate)(((mchunkptr)((char*)(p) +\
|
|
(chunksize(p))))->prev_foot ^ mparams.magic))
|
|
|
|
#define set_inuse(M,p,s)\
|
|
((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
|
|
(((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
|
|
mark_inuse_foot(M,p,s))
|
|
|
|
#define set_inuse_and_pinuse(M,p,s)\
|
|
((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
|
|
(((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
|
|
mark_inuse_foot(M,p,s))
|
|
|
|
#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
|
|
((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
|
|
mark_inuse_foot(M, p, s))
|
|
|
|
#endif /* !FOOTERS */
|
|
|
|
/* ---------------------------- setting mparams -------------------------- */
|
|
|
|
/* Initialize mparams */
|
|
static int init_mparams(void) {
|
|
if (mparams.page_size == 0) {
|
|
size_t s;
|
|
|
|
mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
|
|
mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
|
|
#if MORECORE_CONTIGUOUS
|
|
mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
|
|
#else /* MORECORE_CONTIGUOUS */
|
|
mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
|
|
#endif /* MORECORE_CONTIGUOUS */
|
|
|
|
#if (FOOTERS && !INSECURE)
|
|
{
|
|
#if USE_DEV_RANDOM
|
|
int fd;
|
|
unsigned char buf[sizeof(size_t)];
|
|
/* Try to use /dev/urandom, else fall back on using time */
|
|
if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
|
|
read(fd, buf, sizeof(buf)) == sizeof(buf)) {
|
|
s = *((size_t *) buf);
|
|
close(fd);
|
|
}
|
|
else
|
|
#endif /* USE_DEV_RANDOM */
|
|
s = (size_t)(time(0) ^ (size_t)0x55555555U);
|
|
|
|
s |= (size_t)8U; /* ensure nonzero */
|
|
s &= ~(size_t)7U; /* improve chances of fault for bad values */
|
|
|
|
}
|
|
#else /* (FOOTERS && !INSECURE) */
|
|
s = (size_t)0x58585858U;
|
|
#endif /* (FOOTERS && !INSECURE) */
|
|
ACQUIRE_MAGIC_INIT_LOCK();
|
|
if (mparams.magic == 0) {
|
|
mparams.magic = s;
|
|
/* Set up lock for main malloc area */
|
|
INITIAL_LOCK(&gm->mutex);
|
|
gm->mflags = mparams.default_mflags;
|
|
}
|
|
RELEASE_MAGIC_INIT_LOCK();
|
|
|
|
#ifndef WIN32
|
|
mparams.page_size = malloc_getpagesize;
|
|
mparams.granularity = ((DEFAULT_GRANULARITY != 0)?
|
|
DEFAULT_GRANULARITY : mparams.page_size);
|
|
#else /* WIN32 */
|
|
{
|
|
mparams.page_size = 4096;
|
|
mparams.granularity = 16384;
|
|
}
|
|
#endif /* WIN32 */
|
|
|
|
/* Sanity-check configuration:
|
|
size_t must be unsigned and as wide as pointer type.
|
|
ints must be at least 4 bytes.
|
|
alignment must be at least 8.
|
|
Alignment, min chunk size, and page size must all be powers of 2.
|
|
*/
|
|
if ((sizeof(size_t) != sizeof(char*)) ||
|
|
(MAX_SIZE_T < MIN_CHUNK_SIZE) ||
|
|
(sizeof(int) < 4) ||
|
|
(MALLOC_ALIGNMENT < (size_t)8U) ||
|
|
((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
|
|
((MCHUNK_SIZE & (MCHUNK_SIZE-SIZE_T_ONE)) != 0) ||
|
|
((mparams.granularity & (mparams.granularity-SIZE_T_ONE)) != 0) ||
|
|
((mparams.page_size & (mparams.page_size-SIZE_T_ONE)) != 0))
|
|
ABORT;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* support for mallopt */
|
|
static int change_mparam(int param_number, int value) {
|
|
size_t val = (size_t)value;
|
|
init_mparams();
|
|
switch(param_number) {
|
|
case M_TRIM_THRESHOLD:
|
|
mparams.trim_threshold = val;
|
|
return 1;
|
|
case M_GRANULARITY:
|
|
if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
|
|
mparams.granularity = val;
|
|
return 1;
|
|
}
|
|
else
|
|
return 0;
|
|
case M_MMAP_THRESHOLD:
|
|
mparams.mmap_threshold = val;
|
|
return 1;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
#if DEBUG
|
|
#endif /* DEBUG */
|
|
|
|
/* ----------------------------- statistics ------------------------------ */
|
|
|
|
#if !NO_MALLINFO
|
|
#endif /* !NO_MALLINFO */
|
|
|
|
/* ----------------------- Operations on smallbins ----------------------- */
|
|
|
|
/*
|
|
Various forms of linking and unlinking are defined as macros. Even
|
|
the ones for trees, which are very long but have very short typical
|
|
paths. This is ugly but reduces reliance on inlining support of
|
|
compilers.
|
|
*/
|
|
|
|
/* Link a free chunk into a smallbin */
|
|
#define insert_small_chunk(M, P, S) {\
|
|
bindex_t I = small_index(S);\
|
|
mchunkptr B = smallbin_at(M, I);\
|
|
mchunkptr F = B;\
|
|
assert(S >= MIN_CHUNK_SIZE);\
|
|
if (!smallmap_is_marked(M, I))\
|
|
mark_smallmap(M, I);\
|
|
else if (RTCHECK(ok_address(M, B->fd)))\
|
|
F = B->fd;\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
B->fd = P;\
|
|
F->bk = P;\
|
|
P->fd = F;\
|
|
P->bk = B;\
|
|
}
|
|
|
|
/* Unlink a chunk from a smallbin */
|
|
#define unlink_small_chunk(M, P, S) {\
|
|
mchunkptr F = P->fd;\
|
|
mchunkptr B = P->bk;\
|
|
bindex_t I = small_index(S);\
|
|
assert(P != B);\
|
|
assert(P != F);\
|
|
assert(chunksize(P) == small_index2size(I));\
|
|
if (F == B)\
|
|
clear_smallmap(M, I);\
|
|
else if (RTCHECK((F == smallbin_at(M,I) || ok_address(M, F)) &&\
|
|
(B == smallbin_at(M,I) || ok_address(M, B)))) {\
|
|
F->bk = B;\
|
|
B->fd = F;\
|
|
}\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}
|
|
|
|
/* Unlink the first chunk from a smallbin */
|
|
#define unlink_first_small_chunk(M, B, P, I) {\
|
|
mchunkptr F = P->fd;\
|
|
assert(P != B);\
|
|
assert(P != F);\
|
|
assert(chunksize(P) == small_index2size(I));\
|
|
if (B == F)\
|
|
clear_smallmap(M, I);\
|
|
else if (RTCHECK(ok_address(M, F))) {\
|
|
B->fd = F;\
|
|
F->bk = B;\
|
|
}\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}
|
|
|
|
/* Replace dv node, binning the old one */
|
|
/* Used only when dvsize known to be small */
|
|
#define replace_dv(M, P, S) {\
|
|
size_t DVS = M->dvsize;\
|
|
if (DVS != 0) {\
|
|
mchunkptr DV = M->dv;\
|
|
assert(is_small(DVS));\
|
|
insert_small_chunk(M, DV, DVS);\
|
|
}\
|
|
M->dvsize = S;\
|
|
M->dv = P;\
|
|
}
|
|
|
|
/* ------------------------- Operations on trees ------------------------- */
|
|
|
|
/* Insert chunk into tree */
|
|
#define insert_large_chunk(M, X, S) {\
|
|
tbinptr* H;\
|
|
bindex_t I;\
|
|
compute_tree_index(S, I);\
|
|
H = treebin_at(M, I);\
|
|
X->index = I;\
|
|
X->child[0] = X->child[1] = 0;\
|
|
if (!treemap_is_marked(M, I)) {\
|
|
mark_treemap(M, I);\
|
|
*H = X;\
|
|
X->parent = (tchunkptr)H;\
|
|
X->fd = X->bk = X;\
|
|
}\
|
|
else {\
|
|
tchunkptr T = *H;\
|
|
size_t K = S << leftshift_for_tree_index(I);\
|
|
for (;;) {\
|
|
if (chunksize(T) != S) {\
|
|
tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
|
|
K <<= 1;\
|
|
if (*C != 0)\
|
|
T = *C;\
|
|
else if (RTCHECK(ok_address(M, C))) {\
|
|
*C = X;\
|
|
X->parent = T;\
|
|
X->fd = X->bk = X;\
|
|
break;\
|
|
}\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
break;\
|
|
}\
|
|
}\
|
|
else {\
|
|
tchunkptr F = T->fd;\
|
|
if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
|
|
T->fd = F->bk = X;\
|
|
X->fd = F;\
|
|
X->bk = T;\
|
|
X->parent = 0;\
|
|
break;\
|
|
}\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
break;\
|
|
}\
|
|
}\
|
|
}\
|
|
}\
|
|
}
|
|
|
|
/*
|
|
Unlink steps:
|
|
|
|
1. If x is a chained node, unlink it from its same-sized fd/bk links
|
|
and choose its bk node as its replacement.
|
|
2. If x was the last node of its size, but not a leaf node, it must
|
|
be replaced with a leaf node (not merely one with an open left or
|
|
right), to make sure that lefts and rights of descendents
|
|
correspond properly to bit masks. We use the rightmost descendent
|
|
of x. We could use any other leaf, but this is easy to locate and
|
|
tends to counteract removal of leftmosts elsewhere, and so keeps
|
|
paths shorter than minimally guaranteed. This doesn't loop much
|
|
because on average a node in a tree is near the bottom.
|
|
3. If x is the base of a chain (i.e., has parent links) relink
|
|
x's parent and children to x's replacement (or null if none).
|
|
*/
|
|
|
|
#define unlink_large_chunk(M, X) {\
|
|
tchunkptr XP = X->parent;\
|
|
tchunkptr R;\
|
|
if (X->bk != X) {\
|
|
tchunkptr F = X->fd;\
|
|
R = X->bk;\
|
|
if (RTCHECK(ok_address(M, F))) {\
|
|
F->bk = R;\
|
|
R->fd = F;\
|
|
}\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}\
|
|
else {\
|
|
tchunkptr* RP;\
|
|
if (((R = *(RP = &(X->child[1]))) != 0) ||\
|
|
((R = *(RP = &(X->child[0]))) != 0)) {\
|
|
tchunkptr* CP;\
|
|
while ((*(CP = &(R->child[1])) != 0) ||\
|
|
(*(CP = &(R->child[0])) != 0)) {\
|
|
R = *(RP = CP);\
|
|
}\
|
|
if (RTCHECK(ok_address(M, RP)))\
|
|
*RP = 0;\
|
|
else {\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}\
|
|
}\
|
|
if (XP != 0) {\
|
|
tbinptr* H = treebin_at(M, X->index);\
|
|
if (X == *H) {\
|
|
if ((*H = R) == 0) \
|
|
clear_treemap(M, X->index);\
|
|
}\
|
|
else if (RTCHECK(ok_address(M, XP))) {\
|
|
if (XP->child[0] == X) \
|
|
XP->child[0] = R;\
|
|
else \
|
|
XP->child[1] = R;\
|
|
}\
|
|
else\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
if (R != 0) {\
|
|
if (RTCHECK(ok_address(M, R))) {\
|
|
tchunkptr C0, C1;\
|
|
R->parent = XP;\
|
|
if ((C0 = X->child[0]) != 0) {\
|
|
if (RTCHECK(ok_address(M, C0))) {\
|
|
R->child[0] = C0;\
|
|
C0->parent = R;\
|
|
}\
|
|
else\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
if ((C1 = X->child[1]) != 0) {\
|
|
if (RTCHECK(ok_address(M, C1))) {\
|
|
R->child[1] = C1;\
|
|
C1->parent = R;\
|
|
}\
|
|
else\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}\
|
|
else\
|
|
CORRUPTION_ERROR_ACTION(M);\
|
|
}\
|
|
}\
|
|
}
|
|
|
|
/* Relays to large vs small bin operations */
|
|
|
|
#define insert_chunk(M, P, S)\
|
|
if (is_small(S)) insert_small_chunk(M, P, S)\
|
|
else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
|
|
|
|
#define unlink_chunk(M, P, S)\
|
|
if (is_small(S)) unlink_small_chunk(M, P, S)\
|
|
else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
|
|
|
|
|
|
/* Relays to internal calls to malloc/free from realloc, memalign etc */
|
|
|
|
#if ONLY_MSPACES
|
|
#define internal_malloc(m, b) mspace_malloc(m, b)
|
|
#define internal_free(m, mem) mspace_free(m,mem);
|
|
#else /* ONLY_MSPACES */
|
|
#if MSPACES
|
|
#define internal_malloc(m, b)\
|
|
(m == gm)? dlmalloc(b) : mspace_malloc(m, b)
|
|
#define internal_free(m, mem)\
|
|
if (m == gm) dlfree(mem); else mspace_free(m,mem);
|
|
#else /* MSPACES */
|
|
#define internal_malloc(m, b) dlmalloc(b)
|
|
#define internal_free(m, mem) dlfree(mem)
|
|
#endif /* MSPACES */
|
|
#endif /* ONLY_MSPACES */
|
|
|
|
/* ----------------------- Direct-mmapping chunks ----------------------- */
|
|
|
|
/*
|
|
Directly mmapped chunks are set up with an offset to the start of
|
|
the mmapped region stored in the prev_foot field of the chunk. This
|
|
allows reconstruction of the required argument to MUNMAP when freed,
|
|
and also allows adjustment of the returned chunk to meet alignment
|
|
requirements (especially in memalign). There is also enough space
|
|
allocated to hold a fake next chunk of size SIZE_T_SIZE to maintain
|
|
the PINUSE bit so frees can be checked.
|
|
*/
|
|
|
|
/* Malloc using mmap */
|
|
static void* mmap_alloc(mstate m, size_t nb) {
|
|
size_t mmsize = granularity_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
|
|
if (mmsize > nb) { /* Check for wrap around 0 */
|
|
char* mm = (char*)(DIRECT_MMAP(mmsize));
|
|
if (mm != CMFAIL) {
|
|
size_t offset = align_offset(chunk2mem(mm));
|
|
size_t psize = mmsize - offset - MMAP_FOOT_PAD;
|
|
mchunkptr p = (mchunkptr)(mm + offset);
|
|
p->prev_foot = offset | IS_MMAPPED_BIT;
|
|
(p)->head = (psize|CINUSE_BIT);
|
|
mark_inuse_foot(m, p, psize);
|
|
chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
|
|
chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
|
|
|
|
if (mm < m->least_addr)
|
|
m->least_addr = mm;
|
|
if ((m->footprint += mmsize) > m->max_footprint)
|
|
m->max_footprint = m->footprint;
|
|
assert(is_aligned(chunk2mem(p)));
|
|
check_mmapped_chunk(m, p);
|
|
return chunk2mem(p);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Realloc using mmap */
|
|
static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb) {
|
|
size_t oldsize = chunksize(oldp);
|
|
if (is_small(nb)) /* Can't shrink mmap regions below small size */
|
|
return 0;
|
|
/* Keep old chunk if big enough but not too big */
|
|
if (oldsize >= nb + SIZE_T_SIZE &&
|
|
(oldsize - nb) <= (mparams.granularity << 1))
|
|
return oldp;
|
|
else {
|
|
size_t offset = oldp->prev_foot & ~IS_MMAPPED_BIT;
|
|
size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
|
|
size_t newmmsize = granularity_align(nb + SIX_SIZE_T_SIZES +
|
|
CHUNK_ALIGN_MASK);
|
|
char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
|
|
oldmmsize, newmmsize, 1);
|
|
if (cp != CMFAIL) {
|
|
mchunkptr newp = (mchunkptr)(cp + offset);
|
|
size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
|
|
newp->head = (psize|CINUSE_BIT);
|
|
mark_inuse_foot(m, newp, psize);
|
|
chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
|
|
chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
|
|
|
|
if (cp < m->least_addr)
|
|
m->least_addr = cp;
|
|
if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
|
|
m->max_footprint = m->footprint;
|
|
check_mmapped_chunk(m, newp);
|
|
return newp;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* -------------------------- mspace management -------------------------- */
|
|
|
|
/* Initialize top chunk and its size */
|
|
static void init_top(mstate m, mchunkptr p, size_t psize) {
|
|
/* Ensure alignment */
|
|
size_t offset = align_offset(chunk2mem(p));
|
|
p = (mchunkptr)((char*)p + offset);
|
|
psize -= offset;
|
|
|
|
m->top = p;
|
|
m->topsize = psize;
|
|
p->head = psize | PINUSE_BIT;
|
|
/* set size of fake trailing chunk holding overhead space only once */
|
|
chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
|
|
m->trim_check = mparams.trim_threshold; /* reset on each update */
|
|
}
|
|
|
|
/* Initialize bins for a new mstate that is otherwise zeroed out */
|
|
static void init_bins(mstate m) {
|
|
/* Establish circular links for smallbins */
|
|
bindex_t i;
|
|
for (i = 0; i < NSMALLBINS; ++i) {
|
|
sbinptr bin = smallbin_at(m,i);
|
|
bin->fd = bin->bk = bin;
|
|
}
|
|
}
|
|
|
|
#if PROCEED_ON_ERROR
|
|
|
|
/* default corruption action */
|
|
static void reset_on_error(mstate m) {
|
|
int i;
|
|
++malloc_corruption_error_count;
|
|
/* Reinitialize fields to forget about all memory */
|
|
m->smallbins = m->treebins = 0;
|
|
m->dvsize = m->topsize = 0;
|
|
m->seg.base = 0;
|
|
m->seg.size = 0;
|
|
m->seg.next = 0;
|
|
m->top = m->dv = 0;
|
|
for (i = 0; i < NTREEBINS; ++i)
|
|
*treebin_at(m, i) = 0;
|
|
init_bins(m);
|
|
}
|
|
#endif /* PROCEED_ON_ERROR */
|
|
|
|
/* Allocate chunk and prepend remainder with chunk in successor base. */
|
|
static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
|
|
size_t nb) {
|
|
mchunkptr p = align_as_chunk(newbase);
|
|
mchunkptr oldfirst = align_as_chunk(oldbase);
|
|
size_t psize = (char*)oldfirst - (char*)p;
|
|
mchunkptr q = chunk_plus_offset(p, nb);
|
|
size_t qsize = psize - nb;
|
|
set_size_and_pinuse_of_inuse_chunk(m, p, nb);
|
|
|
|
assert((char*)oldfirst > (char*)q);
|
|
assert(pinuse(oldfirst));
|
|
assert(qsize >= MIN_CHUNK_SIZE);
|
|
|
|
/* consolidate remainder with first chunk of old base */
|
|
if (oldfirst == m->top) {
|
|
size_t tsize = m->topsize += qsize;
|
|
m->top = q;
|
|
q->head = tsize | PINUSE_BIT;
|
|
check_top_chunk(m, q);
|
|
}
|
|
else if (oldfirst == m->dv) {
|
|
size_t dsize = m->dvsize += qsize;
|
|
m->dv = q;
|
|
set_size_and_pinuse_of_free_chunk(q, dsize);
|
|
}
|
|
else {
|
|
if (!cinuse(oldfirst)) {
|
|
size_t nsize = chunksize(oldfirst);
|
|
unlink_chunk(m, oldfirst, nsize);
|
|
oldfirst = chunk_plus_offset(oldfirst, nsize);
|
|
qsize += nsize;
|
|
}
|
|
set_free_with_pinuse(q, qsize, oldfirst);
|
|
insert_chunk(m, q, qsize);
|
|
check_free_chunk(m, q);
|
|
}
|
|
|
|
check_malloced_chunk(m, chunk2mem(p), nb);
|
|
return chunk2mem(p);
|
|
}
|
|
|
|
|
|
/* Add a segment to hold a new noncontiguous region */
|
|
static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
|
|
/* Determine locations and sizes of segment, fenceposts, old top */
|
|
char* old_top = (char*)m->top;
|
|
msegmentptr oldsp = segment_holding(m, old_top);
|
|
char* old_end = oldsp->base + oldsp->size;
|
|
size_t ssize = pad_request(sizeof(struct malloc_segment));
|
|
char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
|
|
size_t offset = align_offset(chunk2mem(rawsp));
|
|
char* asp = rawsp + offset;
|
|
char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
|
|
mchunkptr sp = (mchunkptr)csp;
|
|
msegmentptr ss = (msegmentptr)(chunk2mem(sp));
|
|
mchunkptr tnext = chunk_plus_offset(sp, ssize);
|
|
mchunkptr p = tnext;
|
|
int nfences = 0;
|
|
|
|
/* reset top to new space */
|
|
init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
|
|
|
|
/* Set up segment record */
|
|
assert(is_aligned(ss));
|
|
set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
|
|
*ss = m->seg; /* Push current record */
|
|
m->seg.base = tbase;
|
|
m->seg.size = tsize;
|
|
m->seg.sflags = mmapped;
|
|
m->seg.next = ss;
|
|
|
|
/* Insert trailing fenceposts */
|
|
for (;;) {
|
|
mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
|
|
p->head = FENCEPOST_HEAD;
|
|
++nfences;
|
|
if ((char*)(&(nextp->head)) < old_end)
|
|
p = nextp;
|
|
else
|
|
break;
|
|
}
|
|
assert(nfences >= 2);
|
|
|
|
/* Insert the rest of old top into a bin as an ordinary free chunk */
|
|
if (csp != old_top) {
|
|
mchunkptr q = (mchunkptr)old_top;
|
|
size_t psize = csp - old_top;
|
|
mchunkptr tn = chunk_plus_offset(q, psize);
|
|
set_free_with_pinuse(q, psize, tn);
|
|
insert_chunk(m, q, psize);
|
|
}
|
|
|
|
check_top_chunk(m, m->top);
|
|
}
|
|
|
|
/* -------------------------- System allocation -------------------------- */
|
|
|
|
/* Get memory from system using MORECORE or MMAP */
|
|
static void* sys_alloc(mstate m, size_t nb) {
|
|
char* tbase = CMFAIL;
|
|
size_t tsize = 0;
|
|
flag_t mmap_flag = 0;
|
|
|
|
init_mparams();
|
|
|
|
/* Directly map large chunks */
|
|
if (use_mmap(m) && nb >= mparams.mmap_threshold) {
|
|
void* mem = mmap_alloc(m, nb);
|
|
if (mem != 0)
|
|
return mem;
|
|
}
|
|
|
|
/*
|
|
Try getting memory in any of three ways (in most-preferred to
|
|
least-preferred order):
|
|
1. A call to MORECORE that can normally contiguously extend memory.
|
|
(disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
|
|
or main space is mmapped or a previous contiguous call failed)
|
|
2. A call to MMAP new space (disabled if not HAVE_MMAP).
|
|
Note that under the default settings, if MORECORE is unable to
|
|
fulfill a request, and HAVE_MMAP is true, then mmap is
|
|
used as a noncontiguous system allocator. This is a useful backup
|
|
strategy for systems with holes in address spaces -- in this case
|
|
sbrk cannot contiguously expand the heap, but mmap may be able to
|
|
find space.
|
|
3. A call to MORECORE that cannot usually contiguously extend memory.
|
|
(disabled if not HAVE_MORECORE)
|
|
*/
|
|
|
|
if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
|
|
char* br = CMFAIL;
|
|
msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
|
|
size_t asize = 0;
|
|
ACQUIRE_MORECORE_LOCK();
|
|
|
|
if (ss == 0) { /* First time through or recovery */
|
|
char* base = (char*)CALL_MORECORE(0);
|
|
if (base != CMFAIL) {
|
|
asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
|
|
/* Adjust to end on a page boundary */
|
|
if (!is_page_aligned(base))
|
|
asize += (page_align((size_t)base) - (size_t)base);
|
|
/* Can't call MORECORE if size is negative when treated as signed */
|
|
if (asize < HALF_MAX_SIZE_T &&
|
|
(br = (char*)(CALL_MORECORE(asize))) == base) {
|
|
tbase = base;
|
|
tsize = asize;
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
/* Subtract out existing available top space from MORECORE request. */
|
|
asize = granularity_align(nb - m->topsize + TOP_FOOT_SIZE + SIZE_T_ONE);
|
|
/* Use mem here only if it did continuously extend old space */
|
|
if (asize < HALF_MAX_SIZE_T &&
|
|
(br = (char*)(CALL_MORECORE(asize))) == ss->base+ss->size) {
|
|
tbase = br;
|
|
tsize = asize;
|
|
}
|
|
}
|
|
|
|
if (tbase == CMFAIL) { /* Cope with partial failure */
|
|
if (br != CMFAIL) { /* Try to use/extend the space we did get */
|
|
if (asize < HALF_MAX_SIZE_T &&
|
|
asize < nb + TOP_FOOT_SIZE + SIZE_T_ONE) {
|
|
size_t esize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE - asize);
|
|
if (esize < HALF_MAX_SIZE_T) {
|
|
char* end = (char*)CALL_MORECORE(esize);
|
|
if (end != CMFAIL)
|
|
asize += esize;
|
|
else { /* Can't use; try to release */
|
|
CALL_MORECORE(-asize);
|
|
br = CMFAIL;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (br != CMFAIL) { /* Use the space we did get */
|
|
tbase = br;
|
|
tsize = asize;
|
|
}
|
|
else
|
|
disable_contiguous(m); /* Don't try contiguous path in the future */
|
|
}
|
|
|
|
RELEASE_MORECORE_LOCK();
|
|
}
|
|
|
|
if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */
|
|
size_t req = nb + TOP_FOOT_SIZE + SIZE_T_ONE;
|
|
size_t rsize = granularity_align(req);
|
|
if (rsize > nb) { /* Fail if wraps around zero */
|
|
char* mp = (char*)(CALL_MMAP(rsize));
|
|
if (mp != CMFAIL) {
|
|
tbase = mp;
|
|
tsize = rsize;
|
|
mmap_flag = IS_MMAPPED_BIT;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
|
|
size_t asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
|
|
if (asize < HALF_MAX_SIZE_T) {
|
|
char* br = CMFAIL;
|
|
char* end = CMFAIL;
|
|
ACQUIRE_MORECORE_LOCK();
|
|
br = (char*)(CALL_MORECORE(asize));
|
|
end = (char*)(CALL_MORECORE(0));
|
|
RELEASE_MORECORE_LOCK();
|
|
if (br != CMFAIL && end != CMFAIL && br < end) {
|
|
size_t ssize = end - br;
|
|
if (ssize > nb + TOP_FOOT_SIZE) {
|
|
tbase = br;
|
|
tsize = ssize;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (tbase != CMFAIL) {
|
|
|
|
if ((m->footprint += tsize) > m->max_footprint)
|
|
m->max_footprint = m->footprint;
|
|
|
|
if (!is_initialized(m)) { /* first-time initialization */
|
|
m->seg.base = m->least_addr = tbase;
|
|
m->seg.size = tsize;
|
|
m->seg.sflags = mmap_flag;
|
|
m->magic = mparams.magic;
|
|
init_bins(m);
|
|
if (is_global(m))
|
|
init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
|
|
else {
|
|
/* Offset top by embedded malloc_state */
|
|
mchunkptr mn = next_chunk(mem2chunk(m));
|
|
init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
|
|
}
|
|
}
|
|
|
|
else {
|
|
/* Try to merge with an existing segment */
|
|
msegmentptr sp = &m->seg;
|
|
while (sp != 0 && tbase != sp->base + sp->size)
|
|
sp = sp->next;
|
|
if (sp != 0 &&
|
|
!is_extern_segment(sp) &&
|
|
(sp->sflags & IS_MMAPPED_BIT) == mmap_flag &&
|
|
segment_holds(sp, m->top)) { /* append */
|
|
sp->size += tsize;
|
|
init_top(m, m->top, m->topsize + tsize);
|
|
}
|
|
else {
|
|
if (tbase < m->least_addr)
|
|
m->least_addr = tbase;
|
|
sp = &m->seg;
|
|
while (sp != 0 && sp->base != tbase + tsize)
|
|
sp = sp->next;
|
|
if (sp != 0 &&
|
|
!is_extern_segment(sp) &&
|
|
(sp->sflags & IS_MMAPPED_BIT) == mmap_flag) {
|
|
char* oldbase = sp->base;
|
|
sp->base = tbase;
|
|
sp->size += tsize;
|
|
return prepend_alloc(m, tbase, oldbase, nb);
|
|
}
|
|
else
|
|
add_segment(m, tbase, tsize, mmap_flag);
|
|
}
|
|
}
|
|
|
|
if (nb < m->topsize) { /* Allocate from new or extended top space */
|
|
size_t rsize = m->topsize -= nb;
|
|
mchunkptr p = m->top;
|
|
mchunkptr r = m->top = chunk_plus_offset(p, nb);
|
|
r->head = rsize | PINUSE_BIT;
|
|
set_size_and_pinuse_of_inuse_chunk(m, p, nb);
|
|
check_top_chunk(m, m->top);
|
|
check_malloced_chunk(m, chunk2mem(p), nb);
|
|
return chunk2mem(p);
|
|
}
|
|
}
|
|
|
|
MALLOC_FAILURE_ACTION;
|
|
return 0;
|
|
}
|
|
|
|
/* ----------------------- system deallocation -------------------------- */
|
|
|
|
/* Unmap and unlink any mmapped segments that don't contain used chunks */
|
|
static size_t release_unused_segments(mstate m) {
|
|
size_t released = 0;
|
|
msegmentptr pred = &m->seg;
|
|
msegmentptr sp = pred->next;
|
|
while (sp != 0) {
|
|
char* base = sp->base;
|
|
size_t size = sp->size;
|
|
msegmentptr next = sp->next;
|
|
if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
|
|
mchunkptr p = align_as_chunk(base);
|
|
size_t psize = chunksize(p);
|
|
/* Can unmap if first chunk holds entire segment and not pinned */
|
|
if (!cinuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
|
|
tchunkptr tp = (tchunkptr)p;
|
|
assert(segment_holds(sp, (char*)sp));
|
|
if (p == m->dv) {
|
|
m->dv = 0;
|
|
m->dvsize = 0;
|
|
}
|
|
else {
|
|
unlink_large_chunk(m, tp);
|
|
}
|
|
if (CALL_MUNMAP(base, size) == 0) {
|
|
released += size;
|
|
m->footprint -= size;
|
|
/* unlink obsoleted record */
|
|
sp = pred;
|
|
sp->next = next;
|
|
}
|
|
else { /* back out if cannot unmap */
|
|
insert_large_chunk(m, tp, psize);
|
|
}
|
|
}
|
|
}
|
|
pred = sp;
|
|
sp = next;
|
|
}
|
|
return released;
|
|
}
|
|
|
|
static int sys_trim(mstate m, size_t pad) {
|
|
size_t released = 0;
|
|
if (pad < MAX_REQUEST && is_initialized(m)) {
|
|
pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
|
|
|
|
if (m->topsize > pad) {
|
|
/* Shrink top space in granularity-size units, keeping at least one */
|
|
size_t unit = mparams.granularity;
|
|
size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
|
|
SIZE_T_ONE) * unit;
|
|
msegmentptr sp = segment_holding(m, (char*)m->top);
|
|
|
|
if (!is_extern_segment(sp)) {
|
|
if (is_mmapped_segment(sp)) {
|
|
if (HAVE_MMAP &&
|
|
sp->size >= extra &&
|
|
!has_segment_link(m, sp)) { /* can't shrink if pinned */
|
|
size_t newsize = sp->size - extra;
|
|
/* Prefer mremap, fall back to munmap */
|
|
if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
|
|
(CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
|
|
released = extra;
|
|
}
|
|
}
|
|
}
|
|
else if (HAVE_MORECORE) {
|
|
if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
|
|
extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
|
|
ACQUIRE_MORECORE_LOCK();
|
|
{
|
|
/* Make sure end of memory is where we last set it. */
|
|
char* old_br = (char*)(CALL_MORECORE(0));
|
|
if (old_br == sp->base + sp->size) {
|
|
char* rel_br = (char*)(CALL_MORECORE(-extra));
|
|
char* new_br = (char*)(CALL_MORECORE(0));
|
|
if (rel_br != CMFAIL && new_br < old_br)
|
|
released = old_br - new_br;
|
|
}
|
|
}
|
|
RELEASE_MORECORE_LOCK();
|
|
}
|
|
}
|
|
|
|
if (released != 0) {
|
|
sp->size -= released;
|
|
m->footprint -= released;
|
|
init_top(m, m->top, m->topsize - released);
|
|
check_top_chunk(m, m->top);
|
|
}
|
|
}
|
|
|
|
/* Unmap any unused mmapped segments */
|
|
if (HAVE_MMAP)
|
|
released += release_unused_segments(m);
|
|
|
|
/* On failure, disable autotrim to avoid repeated failed future calls */
|
|
if (released == 0)
|
|
m->trim_check = MAX_SIZE_T;
|
|
}
|
|
|
|
return (released != 0)? 1 : 0;
|
|
}
|
|
|
|
/* ---------------------------- malloc support --------------------------- */
|
|
|
|
/* allocate a large request from the best fitting chunk in a treebin */
|
|
static void* tmalloc_large(mstate m, size_t nb) {
|
|
tchunkptr v = 0;
|
|
size_t rsize = -nb; /* Unsigned negation */
|
|
tchunkptr t;
|
|
bindex_t idx;
|
|
compute_tree_index(nb, idx);
|
|
|
|
if ((t = *treebin_at(m, idx)) != 0) {
|
|
/* Traverse tree for this bin looking for node with size == nb */
|
|
size_t sizebits = nb << leftshift_for_tree_index(idx);
|
|
tchunkptr rst = 0; /* The deepest untaken right subtree */
|
|
for (;;) {
|
|
tchunkptr rt;
|
|
size_t trem = chunksize(t) - nb;
|
|
if (trem < rsize) {
|
|
v = t;
|
|
if ((rsize = trem) == 0)
|
|
break;
|
|
}
|
|
rt = t->child[1];
|
|
t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
|
|
if (rt != 0 && rt != t)
|
|
rst = rt;
|
|
if (t == 0) {
|
|
t = rst; /* set t to least subtree holding sizes > nb */
|
|
break;
|
|
}
|
|
sizebits <<= 1;
|
|
}
|
|
}
|
|
|
|
if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
|
|
binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
|
|
if (leftbits != 0) {
|
|
bindex_t i;
|
|
binmap_t leastbit = least_bit(leftbits);
|
|
compute_bit2idx(leastbit, i);
|
|
t = *treebin_at(m, i);
|
|
}
|
|
}
|
|
|
|
while (t != 0) { /* find smallest of tree or subtree */
|
|
size_t trem = chunksize(t) - nb;
|
|
if (trem < rsize) {
|
|
rsize = trem;
|
|
v = t;
|
|
}
|
|
t = leftmost_child(t);
|
|
}
|
|
|
|
/* If dv is a better fit, return 0 so malloc will use it */
|
|
if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
|
|
if (RTCHECK(ok_address(m, v))) { /* split */
|
|
mchunkptr r = chunk_plus_offset(v, nb);
|
|
assert(chunksize(v) == rsize + nb);
|
|
if (RTCHECK(ok_next(v, r))) {
|
|
unlink_large_chunk(m, v);
|
|
if (rsize < MIN_CHUNK_SIZE)
|
|
set_inuse_and_pinuse(m, v, (rsize + nb));
|
|
else {
|
|
set_size_and_pinuse_of_inuse_chunk(m, v, nb);
|
|
set_size_and_pinuse_of_free_chunk(r, rsize);
|
|
insert_chunk(m, r, rsize);
|
|
}
|
|
return chunk2mem(v);
|
|
}
|
|
}
|
|
CORRUPTION_ERROR_ACTION(m);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* allocate a small request from the best fitting chunk in a treebin */
|
|
static void* tmalloc_small(mstate m, size_t nb) {
|
|
tchunkptr t, v;
|
|
size_t rsize;
|
|
bindex_t i;
|
|
binmap_t leastbit = least_bit(m->treemap);
|
|
compute_bit2idx(leastbit, i);
|
|
|
|
v = t = *treebin_at(m, i);
|
|
rsize = chunksize(t) - nb;
|
|
|
|
while ((t = leftmost_child(t)) != 0) {
|
|
size_t trem = chunksize(t) - nb;
|
|
if (trem < rsize) {
|
|
rsize = trem;
|
|
v = t;
|
|
}
|
|
}
|
|
|
|
if (RTCHECK(ok_address(m, v))) {
|
|
mchunkptr r = chunk_plus_offset(v, nb);
|
|
assert(chunksize(v) == rsize + nb);
|
|
if (RTCHECK(ok_next(v, r))) {
|
|
unlink_large_chunk(m, v);
|
|
if (rsize < MIN_CHUNK_SIZE)
|
|
set_inuse_and_pinuse(m, v, (rsize + nb));
|
|
else {
|
|
set_size_and_pinuse_of_inuse_chunk(m, v, nb);
|
|
set_size_and_pinuse_of_free_chunk(r, rsize);
|
|
replace_dv(m, r, rsize);
|
|
}
|
|
return chunk2mem(v);
|
|
}
|
|
}
|
|
|
|
CORRUPTION_ERROR_ACTION(m);
|
|
return 0;
|
|
}
|
|
|
|
/* --------------------------- realloc support --------------------------- */
|
|
|
|
static void* internal_realloc(mstate m, void* oldmem, size_t bytes) {
|
|
if (bytes >= MAX_REQUEST) {
|
|
MALLOC_FAILURE_ACTION;
|
|
return 0;
|
|
}
|
|
if (!PREACTION(m)) {
|
|
mchunkptr oldp = mem2chunk(oldmem);
|
|
size_t oldsize = chunksize(oldp);
|
|
mchunkptr next = chunk_plus_offset(oldp, oldsize);
|
|
mchunkptr newp = 0;
|
|
void* extra = 0;
|
|
|
|
/* Try to either shrink or extend into top. Else malloc-copy-free */
|
|
|
|
if (RTCHECK(ok_address(m, oldp) && ok_cinuse(oldp) &&
|
|
ok_next(oldp, next) && ok_pinuse(next))) {
|
|
size_t nb = request2size(bytes);
|
|
if (is_mmapped(oldp))
|
|
newp = mmap_resize(m, oldp, nb);
|
|
else if (oldsize >= nb) { /* already big enough */
|
|
size_t rsize = oldsize - nb;
|
|
newp = oldp;
|
|
if (rsize >= MIN_CHUNK_SIZE) {
|
|
mchunkptr remainder = chunk_plus_offset(newp, nb);
|
|
set_inuse(m, newp, nb);
|
|
set_inuse(m, remainder, rsize);
|
|
extra = chunk2mem(remainder);
|
|
}
|
|
}
|
|
else if (next == m->top && oldsize + m->topsize > nb) {
|
|
/* Expand into top */
|
|
size_t newsize = oldsize + m->topsize;
|
|
size_t newtopsize = newsize - nb;
|
|
mchunkptr newtop = chunk_plus_offset(oldp, nb);
|
|
set_inuse(m, oldp, nb);
|
|
newtop->head = newtopsize |PINUSE_BIT;
|
|
m->top = newtop;
|
|
m->topsize = newtopsize;
|
|
newp = oldp;
|
|
}
|
|
}
|
|
else {
|
|
USAGE_ERROR_ACTION(m, oldmem);
|
|
POSTACTION(m);
|
|
return 0;
|
|
}
|
|
|
|
POSTACTION(m);
|
|
|
|
if (newp != 0) {
|
|
if (extra != 0) {
|
|
internal_free(m, extra);
|
|
}
|
|
check_inuse_chunk(m, newp);
|
|
return chunk2mem(newp);
|
|
}
|
|
else {
|
|
void* newmem = internal_malloc(m, bytes);
|
|
if (newmem != 0) {
|
|
size_t oc = oldsize - overhead_for(oldp);
|
|
memcpy(newmem, oldmem, (oc < bytes)? oc : bytes);
|
|
internal_free(m, oldmem);
|
|
}
|
|
return newmem;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* --------------------------- memalign support -------------------------- */
|
|
|
|
static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
|
|
if (alignment <= MALLOC_ALIGNMENT) /* Can just use malloc */
|
|
return internal_malloc(m, bytes);
|
|
if (alignment < MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
|
|
alignment = MIN_CHUNK_SIZE;
|
|
if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
|
|
size_t a = MALLOC_ALIGNMENT << 1;
|
|
while (a < alignment) a <<= 1;
|
|
alignment = a;
|
|
}
|
|
|
|
if (bytes >= MAX_REQUEST - alignment) {
|
|
if (m != 0) { /* Test isn't needed but avoids compiler warning */
|
|
MALLOC_FAILURE_ACTION;
|
|
}
|
|
}
|
|
else {
|
|
size_t nb = request2size(bytes);
|
|
size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
|
|
char* mem = (char*)internal_malloc(m, req);
|
|
if (mem != 0) {
|
|
void* leader = 0;
|
|
void* trailer = 0;
|
|
mchunkptr p = mem2chunk(mem);
|
|
|
|
if (PREACTION(m)) return 0;
|
|
if ((((size_t)(mem)) % alignment) != 0) { /* misaligned */
|
|
/*
|
|
Find an aligned spot inside chunk. Since we need to give
|
|
back leading space in a chunk of at least MIN_CHUNK_SIZE, if
|
|
the first calculation places us at a spot with less than
|
|
MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
|
|
We've allocated enough total room so that this is always
|
|
possible.
|
|
*/
|
|
char* br = (char*)mem2chunk((size_t)(((size_t)(mem +
|
|
alignment -
|
|
SIZE_T_ONE)) &
|
|
-alignment));
|
|
char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
|
|
br : br+alignment;
|
|
mchunkptr newp = (mchunkptr)pos;
|
|
size_t leadsize = pos - (char*)(p);
|
|
size_t newsize = chunksize(p) - leadsize;
|
|
|
|
if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
|
|
newp->prev_foot = p->prev_foot + leadsize;
|
|
newp->head = (newsize|CINUSE_BIT);
|
|
}
|
|
else { /* Otherwise, give back leader, use the rest */
|
|
set_inuse(m, newp, newsize);
|
|
set_inuse(m, p, leadsize);
|
|
leader = chunk2mem(p);
|
|
}
|
|
p = newp;
|
|
}
|
|
|
|
/* Give back spare room at the end */
|
|
if (!is_mmapped(p)) {
|
|
size_t size = chunksize(p);
|
|
if (size > nb + MIN_CHUNK_SIZE) {
|
|
size_t remainder_size = size - nb;
|
|
mchunkptr remainder = chunk_plus_offset(p, nb);
|
|
set_inuse(m, p, nb);
|
|
set_inuse(m, remainder, remainder_size);
|
|
trailer = chunk2mem(remainder);
|
|
}
|
|
}
|
|
|
|
assert (chunksize(p) >= nb);
|
|
assert((((size_t)(chunk2mem(p))) % alignment) == 0);
|
|
check_inuse_chunk(m, p);
|
|
POSTACTION(m);
|
|
if (leader != 0) {
|
|
internal_free(m, leader);
|
|
}
|
|
if (trailer != 0) {
|
|
internal_free(m, trailer);
|
|
}
|
|
return chunk2mem(p);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* ------------------------ comalloc/coalloc support --------------------- */
|
|
|
|
static void** ialloc(mstate m,
|
|
size_t n_elements,
|
|
size_t* sizes,
|
|
int opts,
|
|
void* chunks[]) {
|
|
/*
|
|
This provides common support for independent_X routines, handling
|
|
all of the combinations that can result.
|
|
|
|
The opts arg has:
|
|
bit 0 set if all elements are same size (using sizes[0])
|
|
bit 1 set if elements should be zeroed
|
|
*/
|
|
|
|
size_t element_size; /* chunksize of each element, if all same */
|
|
size_t contents_size; /* total size of elements */
|
|
size_t array_size; /* request size of pointer array */
|
|
void* mem; /* malloced aggregate space */
|
|
mchunkptr p; /* corresponding chunk */
|
|
size_t remainder_size; /* remaining bytes while splitting */
|
|
void** marray; /* either "chunks" or malloced ptr array */
|
|
mchunkptr array_chunk; /* chunk for malloced ptr array */
|
|
flag_t was_enabled; /* to disable mmap */
|
|
size_t size;
|
|
size_t i;
|
|
|
|
/* compute array length, if needed */
|
|
if (chunks != 0) {
|
|
if (n_elements == 0)
|
|
return chunks; /* nothing to do */
|
|
marray = chunks;
|
|
array_size = 0;
|
|
}
|
|
else {
|
|
/* if empty req, must still return chunk representing empty array */
|
|
if (n_elements == 0)
|
|
return (void**)internal_malloc(m, 0);
|
|
marray = 0;
|
|
array_size = request2size(n_elements * (sizeof(void*)));
|
|
}
|
|
|
|
/* compute total element size */
|
|
if (opts & 0x1) { /* all-same-size */
|
|
element_size = request2size(*sizes);
|
|
contents_size = n_elements * element_size;
|
|
}
|
|
else { /* add up all the sizes */
|
|
element_size = 0;
|
|
contents_size = 0;
|
|
for (i = 0; i != n_elements; ++i)
|
|
contents_size += request2size(sizes[i]);
|
|
}
|
|
|
|
size = contents_size + array_size;
|
|
|
|
/*
|
|
Allocate the aggregate chunk. First disable direct-mmapping so
|
|
malloc won't use it, since we would not be able to later
|
|
free/realloc space internal to a segregated mmap region.
|
|
*/
|
|
was_enabled = use_mmap(m);
|
|
disable_mmap(m);
|
|
mem = internal_malloc(m, size - CHUNK_OVERHEAD);
|
|
if (was_enabled)
|
|
enable_mmap(m);
|
|
if (mem == 0)
|
|
return 0;
|
|
|
|
if (PREACTION(m)) return 0;
|
|
p = mem2chunk(mem);
|
|
remainder_size = chunksize(p);
|
|
|
|
assert(!is_mmapped(p));
|
|
|
|
if (opts & 0x2) { /* optionally clear the elements */
|
|
memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
|
|
}
|
|
|
|
/* If not provided, allocate the pointer array as final part of chunk */
|
|
if (marray == 0) {
|
|
size_t array_chunk_size;
|
|
array_chunk = chunk_plus_offset(p, contents_size);
|
|
array_chunk_size = remainder_size - contents_size;
|
|
marray = (void**) (chunk2mem(array_chunk));
|
|
set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
|
|
remainder_size = contents_size;
|
|
}
|
|
|
|
/* split out elements */
|
|
for (i = 0; ; ++i) {
|
|
marray[i] = chunk2mem(p);
|
|
if (i != n_elements-1) {
|
|
if (element_size != 0)
|
|
size = element_size;
|
|
else
|
|
size = request2size(sizes[i]);
|
|
remainder_size -= size;
|
|
set_size_and_pinuse_of_inuse_chunk(m, p, size);
|
|
p = chunk_plus_offset(p, size);
|
|
}
|
|
else { /* the final element absorbs any overallocation slop */
|
|
set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
|
|
break;
|
|
}
|
|
}
|
|
|
|
#if DEBUG
|
|
if (marray != chunks) {
|
|
/* final element must have exactly exhausted chunk */
|
|
if (element_size != 0) {
|
|
assert(remainder_size == element_size);
|
|
}
|
|
else {
|
|
assert(remainder_size == request2size(sizes[i]));
|
|
}
|
|
check_inuse_chunk(m, mem2chunk(marray));
|
|
}
|
|
for (i = 0; i != n_elements; ++i)
|
|
check_inuse_chunk(m, mem2chunk(marray[i]));
|
|
|
|
#endif /* DEBUG */
|
|
|
|
POSTACTION(m);
|
|
return marray;
|
|
}
|
|
|
|
|
|
/* -------------------------- public routines ---------------------------- */
|
|
|
|
#if !ONLY_MSPACES
|
|
|
|
void* dlmalloc(size_t bytes) {
|
|
/*
|
|
Basic algorithm:
|
|
If a small request (< 256 bytes minus per-chunk overhead):
|
|
1. If one exists, use a remainderless chunk in associated smallbin.
|
|
(Remainderless means that there are too few excess bytes to
|
|
represent as a chunk.)
|
|
2. If it is big enough, use the dv chunk, which is normally the
|
|
chunk adjacent to the one used for the most recent small request.
|
|
3. If one exists, split the smallest available chunk in a bin,
|
|
saving remainder in dv.
|
|
4. If it is big enough, use the top chunk.
|
|
5. If available, get memory from system and use it
|
|
Otherwise, for a large request:
|
|
1. Find the smallest available binned chunk that fits, and use it
|
|
if it is better fitting than dv chunk, splitting if necessary.
|
|
2. If better fitting than any binned chunk, use the dv chunk.
|
|
3. If it is big enough, use the top chunk.
|
|
4. If request size >= mmap threshold, try to directly mmap this chunk.
|
|
5. If available, get memory from system and use it
|
|
|
|
The ugly goto's here ensure that postaction occurs along all paths.
|
|
*/
|
|
|
|
if (!PREACTION(gm)) {
|
|
void* mem;
|
|
size_t nb;
|
|
if (bytes <= MAX_SMALL_REQUEST) {
|
|
bindex_t idx;
|
|
binmap_t smallbits;
|
|
nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
|
|
idx = small_index(nb);
|
|
smallbits = gm->smallmap >> idx;
|
|
|
|
if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
|
|
mchunkptr b, p;
|
|
idx += ~smallbits & 1; /* Uses next bin if idx empty */
|
|
b = smallbin_at(gm, idx);
|
|
p = b->fd;
|
|
assert(chunksize(p) == small_index2size(idx));
|
|
unlink_first_small_chunk(gm, b, p, idx);
|
|
set_inuse_and_pinuse(gm, p, small_index2size(idx));
|
|
mem = chunk2mem(p);
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
|
|
else if (nb > gm->dvsize) {
|
|
if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
|
|
mchunkptr b, p, r;
|
|
size_t rsize;
|
|
bindex_t i;
|
|
binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
|
|
binmap_t leastbit = least_bit(leftbits);
|
|
compute_bit2idx(leastbit, i);
|
|
b = smallbin_at(gm, i);
|
|
p = b->fd;
|
|
assert(chunksize(p) == small_index2size(i));
|
|
unlink_first_small_chunk(gm, b, p, i);
|
|
rsize = small_index2size(i) - nb;
|
|
/* Fit here cannot be remainderless if 4byte sizes */
|
|
if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
|
|
set_inuse_and_pinuse(gm, p, small_index2size(i));
|
|
else {
|
|
set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
|
|
r = chunk_plus_offset(p, nb);
|
|
set_size_and_pinuse_of_free_chunk(r, rsize);
|
|
replace_dv(gm, r, rsize);
|
|
}
|
|
mem = chunk2mem(p);
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
|
|
else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
}
|
|
}
|
|
else if (bytes >= MAX_REQUEST)
|
|
nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
|
|
else {
|
|
nb = pad_request(bytes);
|
|
if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
}
|
|
|
|
if (nb <= gm->dvsize) {
|
|
size_t rsize = gm->dvsize - nb;
|
|
mchunkptr p = gm->dv;
|
|
if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
|
|
mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
|
|
gm->dvsize = rsize;
|
|
set_size_and_pinuse_of_free_chunk(r, rsize);
|
|
set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
|
|
}
|
|
else { /* exhaust dv */
|
|
size_t dvs = gm->dvsize;
|
|
gm->dvsize = 0;
|
|
gm->dv = 0;
|
|
set_inuse_and_pinuse(gm, p, dvs);
|
|
}
|
|
mem = chunk2mem(p);
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
|
|
else if (nb < gm->topsize) { /* Split top */
|
|
size_t rsize = gm->topsize -= nb;
|
|
mchunkptr p = gm->top;
|
|
mchunkptr r = gm->top = chunk_plus_offset(p, nb);
|
|
r->head = rsize | PINUSE_BIT;
|
|
set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
|
|
mem = chunk2mem(p);
|
|
check_top_chunk(gm, gm->top);
|
|
check_malloced_chunk(gm, mem, nb);
|
|
goto postaction;
|
|
}
|
|
|
|
mem = sys_alloc(gm, nb);
|
|
|
|
postaction:
|
|
POSTACTION(gm);
|
|
return mem;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void dlfree(void* mem) {
|
|
/*
|
|
Consolidate freed chunks with preceeding or succeeding bordering
|
|
free chunks, if they exist, and then place in a bin. Intermixed
|
|
with special cases for top, dv, mmapped chunks, and usage errors.
|
|
*/
|
|
|
|
if (mem != 0) {
|
|
mchunkptr p = mem2chunk(mem);
|
|
#if FOOTERS
|
|
mstate fm = get_mstate_for(p);
|
|
if (!ok_magic(fm)) {
|
|
USAGE_ERROR_ACTION(fm, p);
|
|
return;
|
|
}
|
|
#else /* FOOTERS */
|
|
#define fm gm
|
|
#endif /* FOOTERS */
|
|
if (!PREACTION(fm)) {
|
|
check_inuse_chunk(fm, p);
|
|
if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
|
|
size_t psize = chunksize(p);
|
|
mchunkptr next = chunk_plus_offset(p, psize);
|
|
if (!pinuse(p)) {
|
|
size_t prevsize = p->prev_foot;
|
|
if ((prevsize & IS_MMAPPED_BIT) != 0) {
|
|
prevsize &= ~IS_MMAPPED_BIT;
|
|
psize += prevsize + MMAP_FOOT_PAD;
|
|
if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
|
|
fm->footprint -= psize;
|
|
goto postaction;
|
|
}
|
|
else {
|
|
mchunkptr prev = chunk_minus_offset(p, prevsize);
|
|
psize += prevsize;
|
|
p = prev;
|
|
if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
|
|
if (p != fm->dv) {
|
|
unlink_chunk(fm, p, prevsize);
|
|
}
|
|
else if ((next->head & INUSE_BITS) == INUSE_BITS) {
|
|
fm->dvsize = psize;
|
|
set_free_with_pinuse(p, psize, next);
|
|
goto postaction;
|
|
}
|
|
}
|
|
else
|
|
goto erroraction;
|
|
}
|
|
}
|
|
|
|
if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
|
|
if (!cinuse(next)) { /* consolidate forward */
|
|
if (next == fm->top) {
|
|
size_t tsize = fm->topsize += psize;
|
|
fm->top = p;
|
|
p->head = tsize | PINUSE_BIT;
|
|
if (p == fm->dv) {
|
|
fm->dv = 0;
|
|
fm->dvsize = 0;
|
|
}
|
|
if (should_trim(fm, tsize))
|
|
sys_trim(fm, 0);
|
|
goto postaction;
|
|
}
|
|
else if (next == fm->dv) {
|
|
size_t dsize = fm->dvsize += psize;
|
|
fm->dv = p;
|
|
set_size_and_pinuse_of_free_chunk(p, dsize);
|
|
goto postaction;
|
|
}
|
|
else {
|
|
size_t nsize = chunksize(next);
|
|
psize += nsize;
|
|
unlink_chunk(fm, next, nsize);
|
|
set_size_and_pinuse_of_free_chunk(p, psize);
|
|
if (p == fm->dv) {
|
|
fm->dvsize = psize;
|
|
goto postaction;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
set_free_with_pinuse(p, psize, next);
|
|
insert_chunk(fm, p, psize);
|
|
check_free_chunk(fm, p);
|
|
goto postaction;
|
|
}
|
|
}
|
|
erroraction:
|
|
USAGE_ERROR_ACTION(fm, p);
|
|
postaction:
|
|
POSTACTION(fm);
|
|
}
|
|
}
|
|
#if !FOOTERS
|
|
#undef fm
|
|
#endif /* FOOTERS */
|
|
}
|
|
|
|
void* dlcalloc(size_t n_elements, size_t elem_size) {
|
|
void* mem;
|
|
size_t req = 0;
|
|
if (n_elements != 0) {
|
|
req = n_elements * elem_size;
|
|
if (((n_elements | elem_size) & ~(size_t)0xffff) &&
|
|
(req / n_elements != elem_size))
|
|
req = MAX_SIZE_T; /* force downstream failure on overflow */
|
|
}
|
|
mem = dlmalloc(req);
|
|
if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
|
|
memset(mem, 0, req);
|
|
return mem;
|
|
}
|
|
|
|
void* dlrealloc(void* oldmem, size_t bytes) {
|
|
if (oldmem == 0)
|
|
return dlmalloc(bytes);
|
|
#ifdef REALLOC_ZERO_BYTES_FREES
|
|
if (bytes == 0) {
|
|
dlfree(oldmem);
|
|
return 0;
|
|
}
|
|
#endif /* REALLOC_ZERO_BYTES_FREES */
|
|
else {
|
|
#if ! FOOTERS
|
|
mstate m = gm;
|
|
#else /* FOOTERS */
|
|
mstate m = get_mstate_for(mem2chunk(oldmem));
|
|
if (!ok_magic(m)) {
|
|
USAGE_ERROR_ACTION(m, oldmem);
|
|
return 0;
|
|
}
|
|
#endif /* FOOTERS */
|
|
return internal_realloc(m, oldmem, bytes);
|
|
}
|
|
}
|
|
|
|
void* dlmemalign(size_t alignment, size_t bytes) {
|
|
return internal_memalign(gm, alignment, bytes);
|
|
}
|
|
|
|
void** dlindependent_calloc(size_t n_elements, size_t elem_size,
|
|
void* chunks[]) {
|
|
size_t sz = elem_size; /* serves as 1-element array */
|
|
return ialloc(gm, n_elements, &sz, 3, chunks);
|
|
}
|
|
|
|
void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
|
|
void* chunks[]) {
|
|
return ialloc(gm, n_elements, sizes, 0, chunks);
|
|
}
|
|
|
|
void* dlvalloc(size_t bytes) {
|
|
size_t pagesz;
|
|
init_mparams();
|
|
pagesz = mparams.page_size;
|
|
return dlmemalign(pagesz, bytes);
|
|
}
|
|
|
|
void* dlpvalloc(size_t bytes) {
|
|
size_t pagesz;
|
|
init_mparams();
|
|
pagesz = mparams.page_size;
|
|
return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
|
|
}
|
|
|
|
int dlmalloc_trim(size_t pad) {
|
|
int result = 0;
|
|
if (!PREACTION(gm)) {
|
|
result = sys_trim(gm, pad);
|
|
POSTACTION(gm);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
size_t dlmalloc_footprint(void) {
|
|
return gm->footprint;
|
|
}
|
|
|
|
size_t dlmalloc_max_footprint(void) {
|
|
return gm->max_footprint;
|
|
}
|
|
|
|
#if !NO_MALLINFO
|
|
struct mallinfo dlmallinfo(void) {
|
|
return internal_mallinfo(gm);
|
|
}
|
|
#endif /* NO_MALLINFO */
|
|
|
|
//void dlmalloc_stats() {
|
|
// internal_malloc_stats(gm);
|
|
//}
|
|
|
|
size_t dlmalloc_usable_size(void* mem) {
|
|
if (mem != 0) {
|
|
mchunkptr p = mem2chunk(mem);
|
|
if (cinuse(p))
|
|
return chunksize(p) - overhead_for(p);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int dlmallopt(int param_number, int value) {
|
|
return change_mparam(param_number, value);
|
|
}
|
|
|
|
#endif /* !ONLY_MSPACES */
|
|
|
|
/* ----------------------------- user mspaces ---------------------------- */
|
|
|
|
#if MSPACES
|
|
#endif /* MSPACES */
|
|
|
|
/* -------------------- Alternative MORECORE functions ------------------- */
|
|
|
|
/*
|
|
Guidelines for creating a custom version of MORECORE:
|
|
|
|
* For best performance, MORECORE should allocate in multiples of pagesize.
|
|
* MORECORE may allocate more memory than requested. (Or even less,
|
|
but this will usually result in a malloc failure.)
|
|
* MORECORE must not allocate memory when given argument zero, but
|
|
instead return one past the end address of memory from previous
|
|
nonzero call.
|
|
* For best performance, consecutive calls to MORECORE with positive
|
|
arguments should return increasing addresses, indicating that
|
|
space has been contiguously extended.
|
|
* Even though consecutive calls to MORECORE need not return contiguous
|
|
addresses, it must be OK for malloc'ed chunks to span multiple
|
|
regions in those cases where they do happen to be contiguous.
|
|
* MORECORE need not handle negative arguments -- it may instead
|
|
just return MFAIL when given negative arguments.
|
|
Negative arguments are always multiples of pagesize. MORECORE
|
|
must not misinterpret negative args as large positive unsigned
|
|
args. You can suppress all such calls from even occurring by defining
|
|
MORECORE_CANNOT_TRIM,
|
|
|
|
As an example alternative MORECORE, here is a custom allocator
|
|
kindly contributed for pre-OSX macOS. It uses virtually but not
|
|
necessarily physically contiguous non-paged memory (locked in,
|
|
present and won't get swapped out). You can use it by uncommenting
|
|
this section, adding some #includes, and setting up the appropriate
|
|
defines above:
|
|
|
|
#define MORECORE osMoreCore
|
|
|
|
There is also a shutdown routine that should somehow be called for
|
|
cleanup upon program exit.
|
|
|
|
#define MAX_POOL_ENTRIES 100
|
|
#define MINIMUM_MORECORE_SIZE (64 * 1024U)
|
|
static int next_os_pool;
|
|
void *our_os_pools[MAX_POOL_ENTRIES];
|
|
|
|
void *osMoreCore(int size)
|
|
{
|
|
void *ptr = 0;
|
|
static void *sbrk_top = 0;
|
|
|
|
if (size > 0)
|
|
{
|
|
if (size < MINIMUM_MORECORE_SIZE)
|
|
size = MINIMUM_MORECORE_SIZE;
|
|
if (CurrentExecutionLevel() == kTaskLevel)
|
|
ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
|
|
if (ptr == 0)
|
|
{
|
|
return (void *) MFAIL;
|
|
}
|
|
// save ptrs so they can be freed during cleanup
|
|
our_os_pools[next_os_pool] = ptr;
|
|
next_os_pool++;
|
|
ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
|
|
sbrk_top = (char *) ptr + size;
|
|
return ptr;
|
|
}
|
|
else if (size < 0)
|
|
{
|
|
// we don't currently support shrink behavior
|
|
return (void *) MFAIL;
|
|
}
|
|
else
|
|
{
|
|
return sbrk_top;
|
|
}
|
|
}
|
|
|
|
// cleanup any allocated memory pools
|
|
// called as last thing before shutting down driver
|
|
|
|
void osCleanupMem(void)
|
|
{
|
|
void **ptr;
|
|
|
|
for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
|
|
if (*ptr)
|
|
{
|
|
PoolDeallocate(*ptr);
|
|
*ptr = 0;
|
|
}
|
|
}
|
|
|
|
*/
|
|
|
|
|
|
/* -----------------------------------------------------------------------
|
|
History:
|
|
V2.8.3 Thu Sep 22 11:16:32 2005 Doug Lea (dl at gee)
|
|
* Add max_footprint functions
|
|
* Ensure all appropriate literals are size_t
|
|
* Fix conditional compilation problem for some #define settings
|
|
* Avoid concatenating segments with the one provided
|
|
in create_mspace_with_base
|
|
* Rename some variables to avoid compiler shadowing warnings
|
|
* Use explicit lock initialization.
|
|
* Better handling of sbrk interference.
|
|
* Simplify and fix segment insertion, trimming and mspace_destroy
|
|
* Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
|
|
* Thanks especially to Dennis Flanagan for help on these.
|
|
|
|
V2.8.2 Sun Jun 12 16:01:10 2005 Doug Lea (dl at gee)
|
|
* Fix memalign brace error.
|
|
|
|
V2.8.1 Wed Jun 8 16:11:46 2005 Doug Lea (dl at gee)
|
|
* Fix improper #endif nesting in C++
|
|
* Add explicit casts needed for C++
|
|
|
|
V2.8.0 Mon May 30 14:09:02 2005 Doug Lea (dl at gee)
|
|
* Use trees for large bins
|
|
* Support mspaces
|
|
* Use segments to unify sbrk-based and mmap-based system allocation,
|
|
removing need for emulation on most platforms without sbrk.
|
|
* Default safety checks
|
|
* Optional footer checks. Thanks to William Robertson for the idea.
|
|
* Internal code refactoring
|
|
* Incorporate suggestions and platform-specific changes.
|
|
Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
|
|
Aaron Bachmann, Emery Berger, and others.
|
|
* Speed up non-fastbin processing enough to remove fastbins.
|
|
* Remove useless cfree() to avoid conflicts with other apps.
|
|
* Remove internal memcpy, memset. Compilers handle builtins better.
|
|
* Remove some options that no one ever used and rename others.
|
|
|
|
V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
|
|
* Fix malloc_state bitmap array misdeclaration
|
|
|
|
V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee)
|
|
* Allow tuning of FIRST_SORTED_BIN_SIZE
|
|
* Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
|
|
* Better detection and support for non-contiguousness of MORECORE.
|
|
Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
|
|
* Bypass most of malloc if no frees. Thanks To Emery Berger.
|
|
* Fix freeing of old top non-contiguous chunk im sysmalloc.
|
|
* Raised default trim and map thresholds to 256K.
|
|
* Fix mmap-related #defines. Thanks to Lubos Lunak.
|
|
* Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
|
|
* Branch-free bin calculation
|
|
* Default trim and mmap thresholds now 256K.
|
|
|
|
V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
|
|
* Introduce independent_comalloc and independent_calloc.
|
|
Thanks to Michael Pachos for motivation and help.
|
|
* Make optional .h file available
|
|
* Allow > 2GB requests on 32bit systems.
|
|
* new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
|
|
Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
|
|
and Anonymous.
|
|
* Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
|
|
helping test this.)
|
|
* memalign: check alignment arg
|
|
* realloc: don't try to shift chunks backwards, since this
|
|
leads to more fragmentation in some programs and doesn't
|
|
seem to help in any others.
|
|
* Collect all cases in malloc requiring system memory into sysmalloc
|
|
* Use mmap as backup to sbrk
|
|
* Place all internal state in malloc_state
|
|
* Introduce fastbins (although similar to 2.5.1)
|
|
* Many minor tunings and cosmetic improvements
|
|
* Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
|
|
* Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
|
|
Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
|
|
* Include errno.h to support default failure action.
|
|
|
|
V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
|
|
* return null for negative arguments
|
|
* Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
|
|
* Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
|
|
(e.g. WIN32 platforms)
|
|
* Cleanup header file inclusion for WIN32 platforms
|
|
* Cleanup code to avoid Microsoft Visual C++ compiler complaints
|
|
* Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
|
|
memory allocation routines
|
|
* Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
|
|
* Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
|
|
usage of 'assert' in non-WIN32 code
|
|
* Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
|
|
avoid infinite loop
|
|
* Always call 'fREe()' rather than 'free()'
|
|
|
|
V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
|
|
* Fixed ordering problem with boundary-stamping
|
|
|
|
V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
|
|
* Added pvalloc, as recommended by H.J. Liu
|
|
* Added 64bit pointer support mainly from Wolfram Gloger
|
|
* Added anonymously donated WIN32 sbrk emulation
|
|
* Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
|
|
* malloc_extend_top: fix mask error that caused wastage after
|
|
foreign sbrks
|
|
* Add linux mremap support code from HJ Liu
|
|
|
|
V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
|
|
* Integrated most documentation with the code.
|
|
* Add support for mmap, with help from
|
|
Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
|
|
* Use last_remainder in more cases.
|
|
* Pack bins using idea from colin@nyx10.cs.du.edu
|
|
* Use ordered bins instead of best-fit threshhold
|
|
* Eliminate block-local decls to simplify tracing and debugging.
|
|
* Support another case of realloc via move into top
|
|
* Fix error occuring when initial sbrk_base not word-aligned.
|
|
* Rely on page size for units instead of SBRK_UNIT to
|
|
avoid surprises about sbrk alignment conventions.
|
|
* Add mallinfo, mallopt. Thanks to Raymond Nijssen
|
|
(raymond@es.ele.tue.nl) for the suggestion.
|
|
* Add `pad' argument to malloc_trim and top_pad mallopt parameter.
|
|
* More precautions for cases where other routines call sbrk,
|
|
courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
|
|
* Added macros etc., allowing use in linux libc from
|
|
H.J. Lu (hjl@gnu.ai.mit.edu)
|
|
* Inverted this history list
|
|
|
|
V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
|
|
* Re-tuned and fixed to behave more nicely with V2.6.0 changes.
|
|
* Removed all preallocation code since under current scheme
|
|
the work required to undo bad preallocations exceeds
|
|
the work saved in good cases for most test programs.
|
|
* No longer use return list or unconsolidated bins since
|
|
no scheme using them consistently outperforms those that don't
|
|
given above changes.
|
|
* Use best fit for very large chunks to prevent some worst-cases.
|
|
* Added some support for debugging
|
|
|
|
V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
|
|
* Removed footers when chunks are in use. Thanks to
|
|
Paul Wilson (wilson@cs.texas.edu) for the suggestion.
|
|
|
|
V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
|
|
* Added malloc_trim, with help from Wolfram Gloger
|
|
(wmglo@Dent.MED.Uni-Muenchen.DE).
|
|
|
|
V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
|
|
|
|
V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
|
|
* realloc: try to expand in both directions
|
|
* malloc: swap order of clean-bin strategy;
|
|
* realloc: only conditionally expand backwards
|
|
* Try not to scavenge used bins
|
|
* Use bin counts as a guide to preallocation
|
|
* Occasionally bin return list chunks in first scan
|
|
* Add a few optimizations from colin@nyx10.cs.du.edu
|
|
|
|
V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
|
|
* faster bin computation & slightly different binning
|
|
* merged all consolidations to one part of malloc proper
|
|
(eliminating old malloc_find_space & malloc_clean_bin)
|
|
* Scan 2 returns chunks (not just 1)
|
|
* Propagate failure in realloc if malloc returns 0
|
|
* Add stuff to allow compilation on non-ANSI compilers
|
|
from kpv@research.att.com
|
|
|
|
V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
|
|
* removed potential for odd address access in prev_chunk
|
|
* removed dependency on getpagesize.h
|
|
* misc cosmetics and a bit more internal documentation
|
|
* anticosmetics: mangled names in macros to evade debugger strangeness
|
|
* tested on sparc, hp-700, dec-mips, rs6000
|
|
with gcc & native cc (hp, dec only) allowing
|
|
Detlefs & Zorn comparison study (in SIGPLAN Notices.)
|
|
|
|
Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
|
|
* Based loosely on libg++-1.2X malloc. (It retains some of the overall
|
|
structure of old version, but most details differ.)
|
|
|
|
*/
|