build: fix alloc (#6) (#11)

Does not fixes `hwa` example in production

Reviewed-on: Rust/Core#11
Co-authored-by: Sanya Kapoor <sanyakapoor2705@gmail.com>
Co-committed-by: Sanya Kapoor <sanyakapoor2705@gmail.com>

.cargo/config.toml

@@ -1,5 +1,6 @@
 [unstable]
 build-std = ["core", "compiler_builtins", "alloc"]
+json-target-spec = true
 
 [build]
 target = "i686-kolibri.json"

Cargo.toml

@@ -21,6 +21,3 @@ path = "examples/dark.rs"
 [profile.release]
 opt-level = "z"
 lto = "thin"
-
-[[example]]
-name = "fs_demo"

examples/fs_demo.rs

@@ -1,10 +0,0 @@
-#![no_std]
-#![no_main]
-
-use kos::fs::read_file;
-
-#[no_mangle]
-pub fn kol_main() {
-    let mut buf = [0u8; 256];
-    let _ = read_file(c"/rd/1/readme.txt", &mut buf);
-}

i686-kolibri.json

@@ -5,7 +5,6 @@
     "dynamic-linking": false,
     "executables": true,
     "has-rpath": true,
-    "is-builtin": false,
     "linker-flavor": "ld.lld",
     "linker": "rust-lld",
     "llvm-target": "i686-unknown-none-code32",
@@ -14,9 +13,9 @@
     "relocation-model": "static",
     "position-independent-executables": false,
     "relro-level": "off",
-    "target-c-int-width": "32",
+    "target-c-int-width": 32,
     "target-endian": "little",
-    "target-pointer-width": "32",
+    "target-pointer-width": 32,
     "vendor": "unknown",
     "disable-redzone": true,
     "panic-strategy": "abort",

rust-toolchain

@@ -1 +1,4 @@
-nightly
+[toolchain]
+channel = "nightly"
+components = ["rust-src", "llvm-tools-preview"]
+profile = "default"

shell.nix

@@ -0,0 +1,14 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.mkShell {
+  packages = with pkgs; [
+    rustup
+    cargo-make
+    cargo-binutils
+    fasm
+  ];
+
+  shellHook = ''
+    export PATH="$HOME/.cargo/bin:$PATH"
+  '';
+}

src/allocation.rs

@@ -36,6 +36,7 @@ pub fn init() {
         unsafe {
             sys::init_heap();
             MAIN_SECTOR = sys::alloc(PAGE_SIZE) as usize;
+            core::ptr::write_bytes(MAIN_SECTOR as *mut u8, 0, PAGE_SIZE); // make sector table start clean
         }
     }
 }
@@ -47,14 +48,14 @@ pub fn malloc(size: usize) -> *mut u8 {
 
             if (addr as usize) != 0 {
                 let sec = addr;
-                let mut hdr = *(addr as *const SectorHeader);
+                let hdr = &mut *(addr as *mut SectorHeader);
                 let sec_start_blocks = (sec as usize) + size_of::<SectorHeader>();
                 if hdr.size_left >= size {
                     let mut j = sec_start_blocks;
                     let mut first_found_block_addr = 0;
 
                     while j <= sec_start_blocks + hdr.size {
-                        let mut block = *(j as *const BlockHeader);
+                        let block = &mut *(j as *mut BlockHeader);
                         match block.sign {
                             Sign::Active => {
                                 // If block is occupated - pass
@@ -63,7 +64,7 @@ pub fn malloc(size: usize) -> *mut u8 {
                             }
 
                             Sign::Free => {
-                                if first_found_block_addr != 0 {
+                                if first_found_block_addr == 0 {
                                     first_found_block_addr = j;
                                 }
 
@@ -73,26 +74,32 @@ pub fn malloc(size: usize) -> *mut u8 {
                                     j += (size_of::<BlockHeader>()) + block.size;
                                 } else if size - sum_size < size_of::<BlockHeader>() {
                                     // Create 2 blocks
-                                    let mut main_block =
-                                        *(first_found_block_addr as *const BlockHeader);
+                                    let main_block =
+                                        &mut *(first_found_block_addr as *mut BlockHeader);
                                     main_block.sign = Sign::Active;
                                     main_block.size = size;
 
-                                    let mut secondary_block = *(first_found_block_addr
-                                        as *const BlockHeader)
-                                        .add(size_of::<BlockHeader>() + size);
-                                    secondary_block.sign = Sign::Free;
-                                    secondary_block.size =
+                                    let secondary_block = (first_found_block_addr
+                                        + size_of::<BlockHeader>()
+                                        + size)
+                                        as *mut BlockHeader;
+                                    (*secondary_block).sign = Sign::Free;
+                                    (*secondary_block).size =
                                         sum_size - size - size_of::<BlockHeader>();
 
+                                    hdr.size_left -= size + size_of::<BlockHeader>();
+
                                     return (first_found_block_addr as *mut u8)
                                         .add(size_of::<BlockHeader>());
                                 } else {
                                     // Create 1 block
-                                    let mut main_block =
-                                        *(first_found_block_addr as *const BlockHeader);
+                                    let main_block =
+                                        &mut *(first_found_block_addr as *mut BlockHeader);
                                     main_block.sign = Sign::Active;
                                     main_block.size = sum_size - size_of::<BlockHeader>();
+
+                                    hdr.size_left -= main_block.size + size_of::<BlockHeader>();
+
                                     return (first_found_block_addr as *mut u8)
                                         .add(size_of::<BlockHeader>());
                                 }
@@ -117,9 +124,11 @@ pub fn malloc(size: usize) -> *mut u8 {
                     }
                 }
             } else {
-                let sec_size = size + PAGE_SIZE - size % PAGE_SIZE;
+                // round requested size up to whole pages
+                let sec_size = (size + PAGE_SIZE - 1) & !(PAGE_SIZE - 1);
                 let new_sec = sys::alloc(sec_size);
                 let sec_hdr = new_sec as *mut SectorHeader;
+                *((MAIN_SECTOR + i * 4) as *mut u32) = new_sec as u32; // remember this sector in the table
                 *sec_hdr = SectorHeader {
                     size: sec_size,
                     size_left: sec_size - size_of::<SectorHeader>(),
@@ -138,26 +147,26 @@ pub fn malloc(size: usize) -> *mut u8 {
 
 fn free(block: *const u8) {
     unsafe {
-        let mut block_hdr = *(block.sub(size_of::<BlockHeader>()) as *mut BlockHeader);
+        let block_hdr = &mut *(block.sub(size_of::<BlockHeader>()) as *mut BlockHeader);
 
         for i in 0..PAGE_SIZE / 4 {
             let addr = *((MAIN_SECTOR + i * 4) as *const u32) as *const u8;
-            let mut hdr = *(addr as *const SectorHeader);
+            if addr.is_null() {
+                continue;
+            }
+            let hdr = &mut *(addr as *mut SectorHeader);
 
             if addr < block && (block as usize) < (addr as usize) + hdr.size {
-                hdr.size_left += block_hdr.size;
+                hdr.size_left += block_hdr.size + size_of::<BlockHeader>();
                 if hdr.size_left == hdr.size - size_of::<SectorHeader>() {
-                    free(addr)
+                    sys::free(addr); // whole sector is free, hand it back to OS
+                    *((MAIN_SECTOR + i * 4) as *mut u32) = 0; // and drop from the table
                 } else {
                     block_hdr.sign = Sign::Free;
                 }
                 break;
             }
         }
-
-        if !sys::free(block) {
-            panic!("Free failed");
-        }
     }
 }
 
@@ -181,4 +190,4 @@ unsafe impl alloc::alloc::GlobalAlloc for GlobalAlloc {
 }
 
 #[global_allocator]
-static ALLOC: GlobalAlloc = GlobalAlloc;
+static ALLOC: GlobalAlloc = GlobalAlloc;

src/fs.rs

@@ -1,58 +0,0 @@
-use core::ffi::CStr;
-use crate::sys::{fs_execute, FsBlock};
-
-fn execute(op: u32, offset: u32, offset_hi: u32, count: u32, buf: *mut u8, path: &CStr) -> Result<(), u32> {
-    let info = FsBlock {
-        operation:  op,
-        offset,
-        offset_hi,
-        byte_count: count,
-        buffer:     buf,
-        _pad:       0,
-        path:       path.as_ptr() as *const u8,
-    };
-    match unsafe { fs_execute(&info) } {
-        0 => Ok(()),
-        e => Err(e),
-    }
-}
-
-pub fn read_file(path: &CStr, buf: &mut [u8]) -> Result<(), u32> {
-    execute(0, 0, 0, buf.len() as u32, buf.as_mut_ptr(), path)
-}
-
-pub fn read_folder(path: &CStr, buf: &mut [u8]) -> Result<(), u32> {
-    execute(1, 0, 0, buf.len() as u32, buf.as_mut_ptr(), path)
-}
-
-pub fn create_file(path: &CStr, buf: &[u8]) -> Result<(), u32> {
-    execute(2, 0, 0, buf.len() as u32, buf.as_ptr() as *mut u8, path)
-}
-
-pub fn write_file(path: &CStr, buf: &[u8]) -> Result<(), u32> {
-    execute(3, 0, 0, buf.len() as u32, buf.as_ptr() as *mut u8, path)
-}
-
-pub fn set_size(path: &CStr, size: u64) -> Result<(), u32> {
-    execute(4, size as u32, (size >> 32) as u32, 0, core::ptr::null_mut(), path)
-}
-
-pub fn get_attributes(path: &CStr, buf: &mut [u8]) -> Result<(), u32> {
-    execute(5, 0, 0, buf.len() as u32, buf.as_mut_ptr(), path)
-}
-
-pub fn set_attributes(path: &CStr, buf: &[u8]) -> Result<(), u32> {
-    execute(6, 0, 0, buf.len() as u32, buf.as_ptr() as *mut u8, path)
-}
-
-pub fn run(path: &CStr) -> Result<(), u32> {
-    execute(7, 0, 0, 0, core::ptr::null_mut(), path)
-}
-
-pub fn delete(path: &CStr) -> Result<(), u32> {
-    execute(8, 0, 0, 0, core::ptr::null_mut(), path)
-}
-
-pub fn create_folder(path: &CStr) -> Result<(), u32> {
-    execute(9, 0, 0, 0, core::ptr::null_mut(), path)
-}

src/func_constants.inc

@@ -20,4 +20,3 @@ SF_SYS_MISC             = 68
     SSF_MEM_ALLOC   = 12
     SSF_MEM_FREE    = 13
     SSF_LOAD_DLL    = 19
-SF_FILE                 = 70

src/lib.rs

@@ -6,7 +6,6 @@ mod nanolibc;
 pub mod allocation;
 pub mod dll;
 pub mod sys;
-pub mod fs;
 
 pub use modules::*;
 

src/nanolibc.rs

@@ -31,3 +31,12 @@ pub unsafe extern "C" fn memcmp(s1: *mut u8, s2: *const u8, n: usize) -> i32 {
 
     0
 }
+
+#[no_mangle]
+pub unsafe extern "C" fn strlen(str: *mut u8) -> usize {
+    let mut len = 0usize;
+    loop {
+        if *str.add(len) == 0 { return len; }
+        len += 1;
+    }
+}

src/sys.rs

@@ -67,19 +67,4 @@ extern "C" {
     // 68.19
     #[link_name = "_load_dll"]
     pub fn load_dll(name: *const u8) -> *const u32;
-
-    // 70
-    #[link_name = "_fs_execute"]
-    pub fn fs_execute(info: *const FsBlock) -> u32;
-}
-
-#[repr(C)]
-pub(crate) struct FsBlock {
-    pub operation:  u32,
-    pub offset:     u32,
-    pub offset_hi:  u32,
-    pub byte_count: u32,
-    pub buffer:     *mut u8,
-    pub _pad:       u8,
-    pub path:       *const u8,
 }

src/syscalls.S

@@ -20,7 +20,6 @@ section '.text'
     public _get_lang
     public _load_dll
     public _set_event_mask
-    public _fs_execute
 
 _exit:
     mov eax, SF_TERMINATE_PROCESS
@@ -144,10 +143,3 @@ _set_event_mask:
     int 0x40
     ret
 
-_fs_execute:
-    push ebx
-    mov eax, SF_FILE
-    mov ebx, [esp + 4 * 2]
-    int 0x40
-    pop ebx
-    ret