newlib-cygwin/newlib/libc/stdlib/nano-mallocr.c

723 lines
21 KiB
C

/*
* Copyright (c) 2012, 2013 ARM Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the company may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Implementation of <<malloc>> <<free>> <<calloc>> <<realloc>>, optional
* as to be reenterable.
*
* Interface documentation refer to malloc.c.
*/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <malloc.h>
#if DEBUG
#include <assert.h>
#else
#undef assert
#define assert(x) ((void)0)
#endif
#ifndef MAX
#define MAX(a,b) ((a) >= (b) ? (a) : (b))
#endif
#define _SBRK_R(X) _sbrk_r(X)
#ifdef INTERNAL_NEWLIB
#include <sys/config.h>
#include <reent.h>
#define RARG struct _reent *reent_ptr,
#define RONEARG struct _reent *reent_ptr
#define RCALL reent_ptr,
#define RONECALL reent_ptr
#define MALLOC_LOCK __malloc_lock(reent_ptr)
#define MALLOC_UNLOCK __malloc_unlock(reent_ptr)
#define RERRNO reent_ptr->_errno
#define nano_malloc _malloc_r
#define nano_free _free_r
#define nano_realloc _realloc_r
#define nano_memalign _memalign_r
#define nano_valloc _valloc_r
#define nano_pvalloc _pvalloc_r
#define nano_calloc _calloc_r
#define nano_cfree _cfree_r
#define nano_malloc_usable_size _malloc_usable_size_r
#define nano_malloc_stats _malloc_stats_r
#define nano_mallinfo _mallinfo_r
#define nano_mallopt _mallopt_r
#else /* ! INTERNAL_NEWLIB */
#define RARG
#define RONEARG
#define RCALL
#define RONECALL
#define MALLOC_LOCK
#define MALLOC_UNLOCK
#define RERRNO errno
#define nano_malloc malloc
#define nano_free free
#define nano_realloc realloc
#define nano_memalign memalign
#define nano_valloc valloc
#define nano_pvalloc pvalloc
#define nano_calloc calloc
#define nano_cfree cfree
#define nano_malloc_usable_size malloc_usable_size
#define nano_malloc_stats malloc_stats
#define nano_mallinfo mallinfo
#define nano_mallopt mallopt
#endif /* ! INTERNAL_NEWLIB */
/* Redefine names to avoid conflict with user names */
#define free_list __malloc_free_list
#define sbrk_start __malloc_sbrk_start
#define current_mallinfo __malloc_current_mallinfo
#define ALIGN_PTR(ptr, align) \
(((ptr) + (align) - (intptr_t)1) & ~((align) - (intptr_t)1))
#define ALIGN_SIZE(size, align) \
(((size) + (align) - (size_t)1) & ~((align) - (size_t)1))
/* Alignment of allocated block */
#define MALLOC_ALIGN (8U)
#define CHUNK_ALIGN (sizeof(void*))
#define MALLOC_PADDING ((MAX(MALLOC_ALIGN, CHUNK_ALIGN)) - CHUNK_ALIGN)
/* as well as the minimal allocation size
* to hold a free pointer */
#define MALLOC_MINSIZE (sizeof(void *))
#define MALLOC_PAGE_ALIGN (0x1000)
#define MAX_ALLOC_SIZE (0x80000000U)
typedef size_t malloc_size_t;
typedef struct malloc_chunk
{
/* --------------------------------------
* chunk->| size |
* --------------------------------------
* | Padding for alignment |
* | This includes padding inserted by |
* | the compiler (to align fields) and |
* | explicit padding inserted by this |
* | implementation. If any explicit |
* | padding is being used then the |
* | sizeof (size) bytes at |
* | mem_ptr - CHUNK_OFFSET must be |
* | initialized with the negative |
* | offset to size. |
* --------------------------------------
* mem_ptr->| When allocated: data |
* | When freed: pointer to next free |
* | chunk |
* --------------------------------------
*/
/* size of the allocated payload area, including size before
CHUNK_OFFSET */
long size;
/* since here, the memory is either the next free block, or data load */
struct malloc_chunk * next;
}chunk;
#define CHUNK_OFFSET ((malloc_size_t)(&(((struct malloc_chunk *)0)->next)))
/* size of smallest possible chunk. A memory piece smaller than this size
* won't be able to create a chunk */
#define MALLOC_MINCHUNK (CHUNK_OFFSET + MALLOC_PADDING + MALLOC_MINSIZE)
/* Forward data declarations */
extern chunk * free_list;
extern char * sbrk_start;
extern struct mallinfo current_mallinfo;
/* Forward function declarations */
extern void * nano_malloc(RARG malloc_size_t);
extern void nano_free (RARG void * free_p);
extern void nano_cfree(RARG void * ptr);
extern void * nano_calloc(RARG malloc_size_t n, malloc_size_t elem);
extern void nano_malloc_stats(RONEARG);
extern malloc_size_t nano_malloc_usable_size(RARG void * ptr);
extern void * nano_realloc(RARG void * ptr, malloc_size_t size);
extern void * nano_memalign(RARG size_t align, size_t s);
extern int nano_mallopt(RARG int parameter_number, int parameter_value);
extern void * nano_valloc(RARG size_t s);
extern void * nano_pvalloc(RARG size_t s);
static inline chunk * get_chunk_from_ptr(void * ptr)
{
/* Assume that there is no explicit padding in the
chunk, and that the chunk starts at ptr - CHUNK_OFFSET. */
chunk * c = (chunk *)((char *)ptr - CHUNK_OFFSET);
/* c->size being negative indicates that there is explicit padding in
the chunk. In which case, c->size is currently the negative offset to
the true size. */
if (c->size < 0) c = (chunk *)((char *)c + c->size);
return c;
}
#ifdef DEFINE_MALLOC
/* List list header of free blocks */
chunk * free_list = NULL;
/* Starting point of memory allocated from system */
char * sbrk_start = NULL;
/** Function sbrk_aligned
* Algorithm:
* Use sbrk() to obtain more memory and ensure it is CHUNK_ALIGN aligned
* Optimise for the case that it is already aligned - only ask for extra
* padding after we know we need it
*/
static void* sbrk_aligned(RARG malloc_size_t s)
{
char *p, *align_p;
if (sbrk_start == NULL) sbrk_start = _SBRK_R(RCALL 0);
p = _SBRK_R(RCALL s);
/* sbrk returns -1 if fail to allocate */
if (p == (void *)-1)
return p;
align_p = (char*)ALIGN_PTR((uintptr_t)p, CHUNK_ALIGN);
if (align_p != p)
{
/* p is not aligned, ask for a few more bytes so that we have s
* bytes reserved from align_p. */
p = _SBRK_R(RCALL align_p - p);
if (p == (void *)-1)
return p;
}
return align_p;
}
/** Function nano_malloc
* Algorithm:
* Walk through the free list to find the first match. If fails to find
* one, call sbrk to allocate a new chunk.
*/
void * nano_malloc(RARG malloc_size_t s)
{
chunk *p, *r;
char * ptr, * align_ptr;
int offset;
malloc_size_t alloc_size;
alloc_size = ALIGN_SIZE(s, CHUNK_ALIGN); /* size of aligned data load */
alloc_size += MALLOC_PADDING; /* padding */
alloc_size += CHUNK_OFFSET; /* size of chunk head */
alloc_size = MAX(alloc_size, MALLOC_MINCHUNK);
if (alloc_size >= MAX_ALLOC_SIZE || alloc_size < s)
{
RERRNO = ENOMEM;
return NULL;
}
MALLOC_LOCK;
p = free_list;
r = p;
while (r)
{
int rem = r->size - alloc_size;
if (rem >= 0)
{
if (rem >= MALLOC_MINCHUNK)
{
if (p == r)
{
/* First item in the list, break it into two chunks
* and return the first one */
r->size = alloc_size;
free_list = (chunk *)((char *)r + alloc_size);
free_list->size = rem;
free_list->next = r->next;
} else {
/* Any other item in the list. Split and return
* the first one */
r->size = alloc_size;
p->next = (chunk *)((char *)r + alloc_size);
p->next->size = rem;
p->next->next = r->next;
}
}
/* Find a chunk that is exactly the size or slightly bigger
* than requested size, just return this chunk */
else if (p == r)
{
/* Now it implies p==r==free_list. Move the free_list
* to next chunk */
free_list = r->next;
}
else
{
/* Normal case. Remove it from free_list */
p->next = r->next;
}
break;
}
p=r;
r=r->next;
}
/* Failed to find a appropriate chunk. Ask for more memory */
if (r == NULL)
{
r = sbrk_aligned(RCALL alloc_size);
/* sbrk returns -1 if fail to allocate */
if (r == (void *)-1)
{
/* sbrk didn't have the requested amount. Let's check
* if the last item in the free list is adjacent to the
* current heap end (sbrk(0)). In that case, only ask
* for the difference in size and merge them */
p = free_list;
r = p;
while (r)
{
p=r;
r=r->next;
}
if ((char *)p + p->size == (char *)_SBRK_R(RCALL 0))
{
/* The last free item has the heap end as neighbour.
* Let's ask for a smaller amount and merge */
alloc_size -= p->size;
alloc_size = ALIGN_SIZE(alloc_size, CHUNK_ALIGN); /* size of aligned data load */
alloc_size += MALLOC_PADDING; /* padding */
alloc_size += CHUNK_OFFSET; /* size of chunk head */
alloc_size = MAX(alloc_size, MALLOC_MINCHUNK);
if (sbrk_aligned(RCALL alloc_size) != (void *)-1)
{
p->size += alloc_size;
r = p;
}
else
{
RERRNO = ENOMEM;
MALLOC_UNLOCK;
return NULL;
}
}
else
{
RERRNO = ENOMEM;
MALLOC_UNLOCK;
return NULL;
}
}
else
{
r->size = alloc_size;
}
}
MALLOC_UNLOCK;
ptr = (char *)r + CHUNK_OFFSET;
align_ptr = (char *)ALIGN_PTR((uintptr_t)ptr, MALLOC_ALIGN);
offset = align_ptr - ptr;
if (offset)
{
/* Initialize sizeof (malloc_chunk.size) bytes at
align_ptr - CHUNK_OFFSET with negative offset to the
size field (at the start of the chunk).
The negative offset to size from align_ptr - CHUNK_OFFSET is
the size of any remaining padding minus CHUNK_OFFSET. This is
equivalent to the total size of the padding, because the size of
any remaining padding is the total size of the padding minus
CHUNK_OFFSET.
Note that the size of the padding must be at least CHUNK_OFFSET.
The rest of the padding is not initialized. */
*(long *)((char *)r + offset) = -offset;
}
assert(align_ptr + size <= (char *)r + alloc_size);
return align_ptr;
}
#endif /* DEFINE_MALLOC */
#ifdef DEFINE_FREE
#define MALLOC_CHECK_DOUBLE_FREE
/** Function nano_free
* Implementation of libc free.
* Algorithm:
* Maintain a global free chunk single link list, headed by global
* variable free_list.
* When free, insert the to-be-freed chunk into free list. The place to
* insert should make sure all chunks are sorted by address from low to
* high. Then merge with neighbor chunks if adjacent.
*/
void nano_free (RARG void * free_p)
{
chunk * p_to_free;
chunk * p, * q;
if (free_p == NULL) return;
p_to_free = get_chunk_from_ptr(free_p);
MALLOC_LOCK;
if (free_list == NULL)
{
/* Set first free list element */
p_to_free->next = free_list;
free_list = p_to_free;
MALLOC_UNLOCK;
return;
}
if (p_to_free < free_list)
{
if ((char *)p_to_free + p_to_free->size == (char *)free_list)
{
/* Chunk to free is just before the first element of
* free list */
p_to_free->size += free_list->size;
p_to_free->next = free_list->next;
}
else
{
/* Insert before current free_list */
p_to_free->next = free_list;
}
free_list = p_to_free;
MALLOC_UNLOCK;
return;
}
q = free_list;
/* Walk through the free list to find the place for insert. */
do
{
p = q;
q = q->next;
} while (q && q <= p_to_free);
/* Now p <= p_to_free and either q == NULL or q > p_to_free
* Try to merge with chunks immediately before/after it. */
if ((char *)p + p->size == (char *)p_to_free)
{
/* Chunk to be freed is adjacent
* to a free chunk before it */
p->size += p_to_free->size;
/* If the merged chunk is also adjacent
* to the chunk after it, merge again */
if ((char *)p + p->size == (char *) q)
{
p->size += q->size;
p->next = q->next;
}
}
#ifdef MALLOC_CHECK_DOUBLE_FREE
else if ((char *)p + p->size > (char *)p_to_free)
{
/* Report double free fault */
RERRNO = ENOMEM;
MALLOC_UNLOCK;
return;
}
#endif
else if ((char *)p_to_free + p_to_free->size == (char *) q)
{
/* Chunk to be freed is adjacent
* to a free chunk after it */
p_to_free->size += q->size;
p_to_free->next = q->next;
p->next = p_to_free;
}
else
{
/* Not adjacent to any chunk. Just insert it. Resulting
* a fragment. */
p_to_free->next = q;
p->next = p_to_free;
}
MALLOC_UNLOCK;
}
#endif /* DEFINE_FREE */
#ifdef DEFINE_CFREE
void nano_cfree(RARG void * ptr)
{
nano_free(RCALL ptr);
}
#endif /* DEFINE_CFREE */
#ifdef DEFINE_CALLOC
/* Function nano_calloc
* Implement calloc simply by calling malloc and set zero */
void * nano_calloc(RARG malloc_size_t n, malloc_size_t elem)
{
malloc_size_t bytes;
void * mem;
if (__builtin_mul_overflow (n, elem, &bytes))
{
RERRNO = ENOMEM;
return NULL;
}
mem = nano_malloc(RCALL bytes);
if (mem != NULL) memset(mem, 0, bytes);
return mem;
}
#endif /* DEFINE_CALLOC */
#ifdef DEFINE_REALLOC
/* Function nano_realloc
* Implement realloc by malloc + memcpy */
void * nano_realloc(RARG void * ptr, malloc_size_t size)
{
void * mem;
chunk * p_to_realloc;
malloc_size_t old_size;
if (ptr == NULL) return nano_malloc(RCALL size);
if (size == 0)
{
nano_free(RCALL ptr);
return NULL;
}
old_size = nano_malloc_usable_size(RCALL ptr);
if (size <= old_size && (old_size >> 1) < size)
return ptr;
mem = nano_malloc(RCALL size);
if (mem != NULL)
{
if (old_size > size)
old_size = size;
memcpy(mem, ptr, old_size);
nano_free(RCALL ptr);
}
return mem;
}
#endif /* DEFINE_REALLOC */
#ifdef DEFINE_MALLINFO
struct mallinfo current_mallinfo={0,0,0,0,0,0,0,0,0,0};
struct mallinfo nano_mallinfo(RONEARG)
{
char * sbrk_now;
chunk * pf;
size_t free_size = 0;
size_t total_size;
MALLOC_LOCK;
if (sbrk_start == NULL) total_size = 0;
else {
sbrk_now = _SBRK_R(RCALL 0);
if (sbrk_now == (void *)-1)
total_size = (size_t)-1;
else
total_size = (size_t) (sbrk_now - sbrk_start);
}
for (pf = free_list; pf; pf = pf->next)
free_size += pf->size;
current_mallinfo.arena = total_size;
current_mallinfo.fordblks = free_size;
current_mallinfo.uordblks = total_size - free_size;
MALLOC_UNLOCK;
return current_mallinfo;
}
#endif /* DEFINE_MALLINFO */
#ifdef DEFINE_MALLOC_STATS
void nano_malloc_stats(RONEARG)
{
nano_mallinfo(RONECALL);
fiprintf(stderr, "max system bytes = %10u\n",
current_mallinfo.arena);
fiprintf(stderr, "system bytes = %10u\n",
current_mallinfo.arena);
fiprintf(stderr, "in use bytes = %10u\n",
current_mallinfo.uordblks);
}
#endif /* DEFINE_MALLOC_STATS */
#ifdef DEFINE_MALLOC_USABLE_SIZE
malloc_size_t nano_malloc_usable_size(RARG void * ptr)
{
chunk * c = (chunk *)((char *)ptr - CHUNK_OFFSET);
int size_or_offset = c->size;
if (size_or_offset < 0)
{
/* Padding is used. Excluding the padding size */
c = (chunk *)((char *)c + c->size);
return c->size - CHUNK_OFFSET + size_or_offset;
}
return c->size - CHUNK_OFFSET;
}
#endif /* DEFINE_MALLOC_USABLE_SIZE */
#ifdef DEFINE_MEMALIGN
/* Function nano_memalign
* Allocate memory block aligned at specific boundary.
* align: required alignment. Must be power of 2. Return NULL
* if not power of 2. Undefined behavior is bigger than
* pointer value range.
* s: required size.
* Return: allocated memory pointer aligned to align
* Algorithm: Malloc a big enough block, padding pointer to aligned
* address, then truncate and free the tail if too big.
* Record the offset of align pointer and original pointer
* in the padding area.
*/
void * nano_memalign(RARG size_t align, size_t s)
{
chunk * chunk_p;
malloc_size_t size_allocated, offset, ma_size, size_with_padding;
char * allocated, * aligned_p;
/* Return NULL if align isn't power of 2 */
if ((align & (align-1)) != 0) return NULL;
align = MAX(align, MALLOC_ALIGN);
/* Make sure ma_size does not overflow */
if (s > __SIZE_MAX__ - CHUNK_ALIGN)
{
RERRNO = ENOMEM;
return NULL;
}
ma_size = ALIGN_SIZE(MAX(s, MALLOC_MINSIZE), CHUNK_ALIGN);
/* Make sure size_with_padding does not overflow */
if (ma_size > __SIZE_MAX__ - (align - MALLOC_ALIGN))
{
RERRNO = ENOMEM;
return NULL;
}
size_with_padding = ma_size + (align - MALLOC_ALIGN);
allocated = nano_malloc(RCALL size_with_padding);
if (allocated == NULL) return NULL;
chunk_p = get_chunk_from_ptr(allocated);
aligned_p = (char *)ALIGN_PTR(
(uintptr_t)((char *)chunk_p + CHUNK_OFFSET),
(uintptr_t)align);
offset = aligned_p - ((char *)chunk_p + CHUNK_OFFSET);
if (offset)
{
if (offset >= MALLOC_MINCHUNK)
{
/* Padding is too large, free it */
chunk * front_chunk = chunk_p;
chunk_p = (chunk *)((char *)chunk_p + offset);
chunk_p->size = front_chunk->size - offset;
front_chunk->size = offset;
nano_free(RCALL (char *)front_chunk + CHUNK_OFFSET);
}
else
{
/* Padding is used. Need to set a jump offset for aligned pointer
* to get back to chunk head */
assert(offset >= sizeof(int));
*(long *)((char *)chunk_p + offset) = -offset;
}
}
size_allocated = chunk_p->size;
if ((char *)chunk_p + size_allocated >
(aligned_p + ma_size + MALLOC_MINCHUNK))
{
/* allocated much more than what's required for padding, free
* tail part */
chunk * tail_chunk = (chunk *)(aligned_p + ma_size);
chunk_p->size = aligned_p + ma_size - (char *)chunk_p;
tail_chunk->size = size_allocated - chunk_p->size;
nano_free(RCALL (char *)tail_chunk + CHUNK_OFFSET);
}
return aligned_p;
}
#endif /* DEFINE_MEMALIGN */
#ifdef DEFINE_MALLOPT
int nano_mallopt(RARG int parameter_number, int parameter_value)
{
return 0;
}
#endif /* DEFINE_MALLOPT */
#ifdef DEFINE_VALLOC
void * nano_valloc(RARG size_t s)
{
return nano_memalign(RCALL MALLOC_PAGE_ALIGN, s);
}
#endif /* DEFINE_VALLOC */
#ifdef DEFINE_PVALLOC
void * nano_pvalloc(RARG size_t s)
{
/* Make sure size given to nano_valloc does not overflow */
if (s > __SIZE_MAX__ - MALLOC_PAGE_ALIGN)
{
RERRNO = ENOMEM;
return NULL;
}
return nano_valloc(RCALL ALIGN_SIZE(s, MALLOC_PAGE_ALIGN));
}
#endif /* DEFINE_PVALLOC */