136 lines
4.6 KiB
C
136 lines
4.6 KiB
C
/* Yet Another Try at encapsulating bfd object files in coff.
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Copyright (C) 1988-2015 Free Software Foundation, Inc.
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Written by Pace Willisson 12/9/88
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This file is obsolete. It needs to be converted to just define a bunch
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of stuff that BFD can use to do coff-encapsulated files. --gnu@cygnus.com
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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/*
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* We only use the coff headers to tell the kernel
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* how to exec the file. Therefore, the only fields that need to
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* be filled in are the scnptr and vaddr for the text and data
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* sections, and the vaddr for the bss. As far as coff is concerned,
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* there is no symbol table, relocation, or line numbers.
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*
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* A normal bsd header (struct exec) is placed after the coff headers,
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* and before the real text. I defined a the new fields 'a_machtype'
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* and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is
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* true, then the bsd header is preceeded by a coff header. Macros
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* like N_TXTOFF and N_TXTADDR use this field to find the bsd header.
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*
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* The only problem is to track down the bsd exec header. The
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* macros HEADER_OFFSET, etc do this.
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*/
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#define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */
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/* Describe the COFF header used for encapsulation. */
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struct coffheader
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{
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/* filehdr */
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unsigned short f_magic;
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unsigned short f_nscns;
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long f_timdat;
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long f_symptr;
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long f_nsyms;
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unsigned short f_opthdr;
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unsigned short f_flags;
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/* aouthdr */
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short magic;
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short vstamp;
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long tsize;
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long dsize;
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long bsize;
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long entry;
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long text_start;
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long data_start;
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struct coffscn
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{
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char s_name[8];
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long s_paddr;
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long s_vaddr;
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long s_size;
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long s_scnptr;
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long s_relptr;
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long s_lnnoptr;
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unsigned short s_nreloc;
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unsigned short s_nlnno;
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long s_flags;
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} scns[3];
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};
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/* Describe some of the parameters of the encapsulation,
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including how to find the encapsulated BSD header. */
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/* FIXME, this is dumb. The same tools can't handle a.outs for different
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architectures, just because COFF_MAGIC is different; so you need a
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separate GNU nm for every architecture!!? Unfortunately, it needs to
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be this way, since the COFF_MAGIC value is determined by the kernel
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we're trying to fool here. */
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#define COFF_MAGIC_I386 0514 /* I386MAGIC */
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#define COFF_MAGIC_M68K 0520 /* MC68MAGIC */
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#ifdef COFF_MAGIC
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short __header_offset_temp;
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#define HEADER_OFFSET(f) \
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(__header_offset_temp = 0, \
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fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \
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fseek ((f), -sizeof (short), 1), \
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__header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0)
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#else
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#define HEADER_OFFSET(f) 0
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#endif
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#define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1))
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/* Describe the characteristics of the BSD header
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that appears inside the encapsulation. */
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/* Encapsulated coff files that are linked ZMAGIC have a text segment
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offset just past the header (and a matching TXTADDR), excluding
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the headers from the text segment proper but keeping the physical
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layout and the virtual memory layout page-aligned.
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Non-encapsulated a.out files that are linked ZMAGIC have a text
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segment that starts at 0 and an N_TXTADR similarly offset to 0.
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They too are page-aligned with each other, but they include the
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a.out header as part of the text.
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The _N_HDROFF gets sizeof struct exec added to it, so we have
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to compensate here. See <a.out.gnu.h>. */
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#undef _N_HDROFF
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#undef N_TXTADDR
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#undef N_DATADDR
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#define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
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sizeof (struct coffheader) : 0)
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/* Address of text segment in memory after it is loaded. */
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#define N_TXTADDR(x) \
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((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
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sizeof (struct coffheader) + sizeof (struct exec) : 0)
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#define SEGMENT_SIZE 0x400000
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#define N_DATADDR(x) \
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((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \
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(SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \
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(N_TXTADDR(x)+(x).a_text))
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