; System allocator.
; Based on dlmalloc 2.8.6.
; dlmalloc is written by Doug Lea and released to the public domain.
; Algorithms are the same as in dlmalloc, with the following differences:
; * segment management uses large segments,
; since segments can never be merged;
; * top chunk is usually large, so the code tries mmap
; for chunks with size >= mmap_threshold before allocating from top;
; * there is additional bookkeeping for releasing physical memory
; instead of relying on unmapping entire segments:
; tree chunks have additional field in the end,
; all recently expanded tree chunks are linked in one list for sys_trim;
; * there is an additional list of all mmapped chunks,
; so that mspace_destroy can free everything, including mmapped chunks;
; * realloc and memalign can give back a space before a free chunk
; (extending that chunk) even if a space is less than minimal chunk size.
; Statistics:
; Alignment: 8 bytes
; Minimum overhead per allocated chunk: 4 or 8 bytes,
; depending on whether FOOTERS is defined.
; Minimum allocated size: 16 bytes (including overhead)
; See details at http://gee.cs.oswego.edu/dl/html/malloc.html.
; The KolibriOS kernel provides functions similar to mmap/mremap/munmap,
; they are used as base for allocations.
FOOTERS = 0
; If true, provide extra checking and dispatching by placing
; information in the footers of allocated chunks. This adds
; space and time overhead, but can be useful for debugging.
DEFAULT_MMAP_THRESHOLD = 256*1024
; The request size threshold for using MMAP to directly service a
; request. Requests of at least this size that cannot be allocated
; using already-existing space will be serviced via mmap. (If enough
; normal freed space already exists it is used instead.) Using mmap
; segregates relatively large chunks of memory so that they can be
; individually obtained and released from the host system. A request
; serviced through mmap is never reused by any other request (at least
; not directly; the system may just so happen to remap successive
; requests to the same locations). Segregating space in this way has
; 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 0xFFFFFFFF.
RELEASE_CHECK_RATE = 64
; The number of consolidated frees between checks to release
; unused segments when freeing. When using non-contiguous segments,
; especially with multiple mspaces, checking only for topmost space
; doesn't always suffice to trigger trimming. To compensate for this,
; free() will, with a period of MAX_RELEASE_CHECK_RATE (or the
; current number of segments, if greater) try to release unused
; segments to the OS when freeing chunks that result in
; consolidation. The best value for this parameter is a compromise
; between slowing down frees with relatively costly checks that
; rarely trigger versus holding on to unused memory. To effectively
; disable, set to MAX_SIZE_T. This may lead to a very slight speed
; improvement at the expense of carrying around more memory.
DEFAULT_MSPACE_SIZE = 1024*1024
include 'malloc_internal.inc'
prologue@proc equ fpo_prologue
epilogue@proc equ fpo_epilogue
; void* create_mspace(size_t capacity, int locked)
; create_mspace creates and returns a new independent space with the
; given initial capacity, or, if 0, the default mspace size. It
; returns null if there is no system memory available to create the
; space. If argument locked is non-zero, the space uses a separate
; lock to control access. The capacity of the space will grow
; dynamically as needed to service mspace_malloc requests.
proc create_mspace stdcall uses ebx, capacity, locked
do_create_mspace
endp
; void destroy_mspace(mspace msp)
; destroy_mspace destroys the given space, and attempts to return all
; of its memory back to the system, returning the total number of
; bytes freed. After destruction, the results of access to all memory
; used by the space become undefined.
proc destroy_mspace stdcall uses ebx, msp
do_destroy_mspace
endp
macro set_default_heap
{
mov ebp, [default_heap]
.got_mspace:
}
macro set_explicit_heap
{
mov ebp, [msp]
}
macro mspace_adapter common_label
{
mov eax, [esp]
mov [esp], ebp
mov ebp, [esp+4]
mov [esp+4], eax
push ebx
push esi
jmp common_label
}
; void* malloc(size_t bytes)
; 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.
align 16
proc malloc stdcall uses ebp ebx esi, bytes
set_default_heap
do_malloc
endp
; void free(void* mem)
; Releases the chunk of memory pointed to by mem, that had been previously
; allocated using malloc or a related routine such as realloc.
; It has no effect if mem is null. If mem was not malloced or already
; freed, free(mem) will by default cause the current program to abort.
align 16
proc free stdcall uses ebp ebx esi, mem
set_default_heap
do_free
endp
; void* calloc(size_t n_elements, size_t elem_size);
; Returns a pointer to n_elements * elem_size bytes, with all locations
; set to zero.
align 16
proc calloc stdcall, n_elements, elem_size
do_calloc <stdcall malloc,eax>
endp
; void* realloc(void* oldmem, size_t bytes)
; Returns a pointer to a chunk of size bytes that contains the same data
; as does chunk oldmem up to the minimum of (bytes, oldmem's size) bytes, or null
; if no space is available.
;
; The returned pointer may or may not be the same as oldmem. The algorithm
; prefers extending oldmem in most cases when possible, otherwise it
; employs the equivalent of a malloc-copy-free sequence.
;
; If oldmem is null, realloc is equivalent to malloc.
;
; If space is not available, realloc returns null, errno is set (if on
; ANSI) and oldmem is NOT freed.
;
; if bytes is for fewer bytes than already held by oldmem, 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.
align 16
proc realloc stdcall uses ebp ebx esi, oldmem, bytes
set_default_heap
if used mspace_realloc
do_realloc <stdcall mspace_malloc,ebp,>, <stdcall mspace_free,ebp,>
else
do_realloc <stdcall malloc,>, <stdcall free,>
end if
endp
; void* realloc_in_place(void* oldmem, size_t bytes)
; Resizes the space allocated for oldmem to size bytes, only if this can be
; done without moving oldmem (i.e., only if there is adjacent space
; available if bytes is greater than oldmem's current allocated size, or bytes is
; less than or equal to oldmem's size). This may be used instead of plain
; realloc if an alternative allocation strategy is needed upon failure
; to expand space; for example, reallocation of a buffer that must be
; memory-aligned or cleared. You can use realloc_in_place to trigger
; these alternatives only when needed.
;
; Returns oldmem if successful; otherwise null.
align 16
proc realloc_in_place stdcall uses ebp ebx esi, oldmem, bytes
set_default_heap
do_realloc_in_place
endp
; void* memalign(size_t alignment, size_t bytes);
; Returns a pointer to a newly allocated chunk of bytes argument, 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.
align 16
proc memalign stdcall uses ebp ebx esi, alignment, bytes
set_default_heap
if used mspace_memalign
do_memalign <stdcall mspace_malloc,ebp,>
else
do_memalign <stdcall malloc,>
end if
endp
; void* mspace_malloc(mspace msp, size_t bytes)
; mspace_malloc behaves as malloc, but operates within
; the given space.
align 16
proc mspace_malloc ;stdcall uses ebp ebx esi, msp, bytes
; set_explicit_heap
; do_malloc
mspace_adapter malloc.got_mspace
endp
; void mspace_free(mspace msp, void* mem)
; mspace_free behaves as free, but operates within
; the given space.
align 16
proc mspace_free ;stdcall uses ebp ebx esi, msp, mem
; set_explicit_heap
; do_free
mspace_adapter free.got_mspace
endp
; void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size)
; mspace_calloc behaves as calloc, but operates within
; the given space.
align 16
proc mspace_calloc stdcall, msp, n_elements, elem_size
do_calloc <stdcall mspace_malloc,[msp+4],eax>
endp
; void* mspace_realloc(mspace msp, void* oldmem, size_t bytes)
; mspace_realloc behaves as realloc, but operates within
; the given space.
align 16
proc mspace_realloc ;stdcall uses ebp ebx esi, msp, oldmem, bytes
; set_explicit_heap
; do_realloc <stdcall mspace_malloc,ebp,>, <stdcall mspace_free,ebp,>
mspace_adapter realloc.got_mspace
endp
; void* mspace_realloc_in_place(mspace msp, void* oldmem, size_t bytes)
align 16
proc mspace_realloc_in_place ;stdcall uses ebp ebx esi, msp, oldmem, bytes
; set_explicit_heap
; do_realloc_in_place
mspace_adapter realloc_in_place.got_mspace
endp
; void* mspace_memalign(mspace msp, size_t alignment, size_t bytes)
; mspace_memalign behaves as memalign, but operates within
; the given space.
align 16
proc mspace_memalign ;stdcall uses ebp ebx esi, msp, alignment, bytes
; set_explicit_heap
; do_memalign <stdcall mspace_malloc,ebp,>
mspace_adapter memalign.got_mspace
endp
assert MALLOC_ALIGNMENT >= 8
assert MALLOC_ALIGNMENT and (MALLOC_ALIGNMENT - 1) = 0
assert MCHUNK_SIZE and (MCHUNK_SIZE - 1) = 0
; in: edx = initial size of the process heap
macro malloc_init
{
if FOOTERS
mov eax, 26
mov ebx, 9
call FS_SYSCALL_PTR
xor eax, 0x55555555
or eax, 8
and eax, not 7
mov [malloc_magic], eax
end if
stdcall create_mspace, edx, 1
mov [default_heap], eax
}
proc heap_corrupted
sub esp, 400h
mov eax, 9
mov ebx, esp
or ecx, -1
call FS_SYSCALL_PTR
lea esi, [ebx+10]
lea edx, [ebx+10+11]
mov eax, 63
mov ebx, 1
mov cl, '['
call FS_SYSCALL_PTR
@@:
mov cl, [esi]
test cl, cl
jz @f
call FS_SYSCALL_PTR
inc esi
cmp esi, edx
jb @b
@@:
mov esi, heap_corrupted_msg
@@:
mov cl, [esi]
inc esi
test cl, cl
jz @f
mov eax, 63
mov ebx, 1
call FS_SYSCALL_PTR
jmp @b
@@:
or eax, -1
or ebx, -1
call FS_SYSCALL_PTR
endp
heap_corrupted_msg db '] Heap corrupted, aborting',13,10,0