malloc.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

#ifdef L_malloc
Block_t *__init_block(Block_t * b, char *pppp, size_t sz)
{
	Block_t *p;

	memset(b, 0, sizeof(Block_t));
	b->ptr = pppp;
	b->size = sz;
	__ptrs_ins(b);
	FREE_MEM_INS_BLOCK(b);
	return p;
}
#endif							/* L_malloc */

/* `b` is current block, `sz` its new size */
/* block `b` will be splitted to one busy & one free block */
#define SPLIT_BLOCK(b,sz) \
{\
  Block_t *bt; \
  bt = bl_get(); \
  INIT_BLOCK(bt, b->ptr + sz, b->size - sz); \
  b->size = sz; \
  if (__bl_last == b) __bl_last = bt; \
  __bl_uncommit(bt);\
}

/* `b` is current block, `pp` is next free block, `sz` is needed size */
#define SHRINK_BLOCK(b,pp,sz) \
{\
  FREE_MEM_DEL_BLOCK(pp,p); \
  pp->ptr = b->ptr + sz; \
  pp->size += b->size - sz; \
  b->size = sz; \
  FREE_MEM_INS_BLOCK(pp); \
  __bl_uncommit(pp); \
}

#ifdef L_malloc
static Block_t *bl_mapnew(size_t size)
{
	size_t map_size;
	Block_t *pp, *p;
	void *pt;

	map_size = PAGE_ALIGN(size);
	pt = mmap(LARGE_MSTART, map_size, PROT_READ | PROT_WRITE | PROT_EXEC,
#ifdef __UCLIBC_HAS_MMU__
							 MAP_PRIVATE | MAP_ANONYMOUS
#else
							 MAP_SHARED | MAP_ANONYMOUS
#endif
							 , 0, 0);

	if (pt == MAP_FAILED)
		return (Block_t *) NULL;

	__bl_last = pp = bl_get();
	INIT_BLOCK(pp, (char *) pt, map_size);
	pp->broken = 1;

	return pp;
}

void __bl_uncommit(Block_t * b)
{
	char *u_start, *u_end;

	u_start = PAGE_ALIGNP(b->ptr);
	u_end = PAGE_DOWNALIGNP(b->ptr + b->size);
	if (u_end <= u_start)
		return;

#if M_DOTRIMMING
	mmap(u_start, u_end - u_start, PROT_READ | PROT_WRITE | PROT_EXEC,
#ifdef __UCLIBC_HAS_MMU__
							 MAP_PRIVATE | MAP_ANONYMOUS |MAP_FIXED
#else
							 MAP_SHARED | MAP_ANONYMOUS |MAP_FIXED
#endif
							 , 0, 0);
#endif
}

/* requested size must be aligned to ALIGNMENT */
static Block_t *bl_alloc(size_t size)
{
	Block_t *p, *pp;

	/* try to find needed space in existing memory */
	for (p = free_mem_root, pp = NULL; p;) {
		if (p->size > size) {
			pp = p;
			p = p->l_free_mem;
		} else if (p->size < size)
			p = p->r_free_mem;
		else {
			pp = p;
			break;
		}
	}

	if (!pp) {					/* map some memory */
		if (!__bl_last) {		/* just do initial mmap */
			pp = bl_mapnew(size);
			if (!pp)
				return NULL;
		} else if (!__bl_last->used) {	/* try growing last unused */
			if (mremap(PAGE_DOWNALIGNP(__bl_last->ptr),
					   PAGE_ALIGNP(__bl_last->ptr + __bl_last->size) -
					   PAGE_DOWNALIGNP(__bl_last->ptr),
					   PAGE_ALIGNP(__bl_last->ptr + size) -
					   PAGE_DOWNALIGNP(__bl_last->ptr), 0) == MAP_FAILED) {	/* unable to grow -- initiate new block */
				pp = bl_mapnew(size);
				if (!pp)
					return NULL;
			} else {
				pp = __bl_last;
				FREE_MEM_DEL_BLOCK(pp, p);
				pp->size = PAGE_ALIGNP(pp->ptr + size) - pp->ptr;
				FREE_MEM_INS_BLOCK(pp);
			}
		} else {				/* __bl_last is used block */
			if (mremap(PAGE_DOWNALIGNP(__bl_last->ptr),
					   PAGE_ALIGNP(__bl_last->ptr + __bl_last->size) -
					   PAGE_DOWNALIGNP(__bl_last->ptr),
					   PAGE_ALIGNP(__bl_last->ptr + __bl_last->size +
								   size) - PAGE_DOWNALIGNP(__bl_last->ptr),
					   0) == MAP_FAILED) {
				pp = bl_mapnew(size);
				if (!pp)
					return NULL;
			} else {
				pp = bl_get();
				INIT_BLOCK(pp, __bl_last->ptr + __bl_last->size,
						   PAGE_ALIGNP(__bl_last->ptr + __bl_last->size +
									   size) - __bl_last->ptr -
						   __bl_last->size);
				__bl_last = pp;
			}
		}
	}

	/* just delete this node from free_mem tree */
	if (pp->next)
		__free_mem_replace(pp->next);
	else
		__free_mem_del(pp);
	pp->used = 1;

	if (pp->size - size > MALLOC_ALIGN) {	/* this block can be splitted (it is unused,not_broken) */
		SPLIT_BLOCK(pp, size);
	}

	return pp;
}
#endif							/* L_malloc */

#ifdef L__free_support
void __bl_free(Block_t * b)
{
	Block_t *p, *bl_next, *bl_prev;

	/* Look for blocks before & after `b` */
	for (p = ptrs_root, bl_next = NULL, bl_prev = NULL; p;) {
		if (p->ptr > b->ptr) {
			bl_next = p;
			p = p->l_ptrs;
		} else if (p->ptr < b->ptr) {
			bl_prev = p;
			p = p->r_ptrs;
		} else
			break;
	}
	if (b->l_ptrs)
		for (bl_prev = b->l_ptrs; bl_prev->r_ptrs;
			 bl_prev = bl_prev->r_ptrs);
	if (b->r_ptrs)
		for (bl_next = b->r_ptrs; bl_next->l_ptrs;
			 bl_next = bl_next->l_ptrs);

	if (bl_next && !bl_next->broken && !bl_next->used) {
		FREE_MEM_DEL_BLOCK(bl_next, p)
			COMBINE_BLOCKS(b, bl_next)
	}

	if (bl_prev && !b->broken && !bl_prev->used) {
		FREE_MEM_DEL_BLOCK(bl_prev, p)
			COMBINE_BLOCKS(bl_prev, b)
			b = bl_prev;
	}

	b->used = 0;
	FREE_MEM_INS_BLOCK(b)
		__bl_uncommit(b);
}
#endif							/* L__free_support */

extern void __malloc_init(void);

#ifdef L__malloc_init
void __malloc_init(void)
{
	int i, mapsize, x, old_x, gcount;

	mapsize = M_PAGESIZE;

	__malloc_initialized = 0;
	__bl_last = NULL;
	free_mem_root = NULL;
	ptrs_root = NULL;
	mapsize -= sizeof(Hunk_t);
	for (i = 1; i <= HUNK_MAXSIZE; i++) {
		__free_h[i] = (Hunk_t *) NULL;
		for (x = mapsize / i, gcount = 0, old_x = 0; old_x != x;) {
			old_x = x;
			x = (mapsize - ALIGN(DIV8(old_x + 7))) / i;
			if (gcount > 1 && x * i + ALIGN(DIV8(x + 7)) <= mapsize)
				break;
			if (x * i + ALIGN(DIV8(x + 7)) > mapsize)
				gcount++;
		}
		__total_h[i] = x;
	}
	mutex_init(&malloc_lock);
	__malloc_initialized = 1;
	// fprintf(stderr, "malloc_init: hunk_t=%d\n", sizeof(Hunk_t));
}
#endif							/* L__malloc_init */

#ifdef L_malloc
void *malloc(size_t size)
{
	void *p;

	if (size == 0)
		return NULL;

	if (__malloc_initialized < 0)
		__malloc_init();
	if (__malloc_initialized)
		mutex_lock(&malloc_lock);

	if (size <= HUNK_MAXSIZE)
		p = __hunk_alloc(size);
	else {
		if ((p = bl_alloc(ALIGN(size))) != NULL)
			p = ((Block_t *) p)->ptr;
	}

	if (__malloc_initialized)
		mutex_unlock(&malloc_lock);

	// fprintf(stderr, "malloc returning: s=%d, p=%p\n", size, p);
	return p;
}
#endif							/* L_malloc */

#ifdef L_free
void free(void *ptr)
{
	Block_t *p, *best;

	if (__malloc_initialized < 0)
		return;
	if (__malloc_initialized)
		mutex_lock(&malloc_lock);

	for (p = ptrs_root, best = NULL; p;) {
		if (p->ptr > (char *) ptr)
			p = p->l_ptrs;
		else {
			best = p;
			p = p->r_ptrs;
		}
	}

	if (!best || !best->used || best->ptr != (char *) ptr) {
		__hunk_free(ptr);
		if (__malloc_initialized)
			mutex_unlock(&malloc_lock);
		return;
	}

	__bl_free(best);

	if (__malloc_initialized)
		mutex_unlock(&malloc_lock);
}
#endif							/* L_free */

extern void *_realloc_no_move(void *ptr, size_t size);

#ifdef L__realloc_no_move
void *_realloc_no_move(void *ptr, size_t size)
{
	Block_t *p, *best, *next;

	if (size <= HUNK_MAXSIZE)
		return NULL;

	if (__malloc_initialized <= 0)
		return malloc(size);

	mutex_lock(&malloc_lock);

	/* Locate block */
	for (p = ptrs_root, best = NULL; p;) {
		if (p->ptr > (char *) ptr)
			p = p->l_ptrs;
		else {
			best = p;
			p = p->r_ptrs;
		}
	}

	if (!best || !best->used || best->ptr != (char *) ptr) {
		mutex_unlock(&malloc_lock);
		return NULL;
	}

	size = ALIGN(size);

	if (size == best->size) {
		mutex_unlock(&malloc_lock);
		return ptr;
	}

	if (best->r_ptrs)			/* get block just after */
		for (next = best->r_ptrs; next->l_ptrs; next = next->l_ptrs);
	else
		for (p = ptrs_root, next = NULL; p;) {
			if (p->ptr > best->ptr) {
				next = p;
				p = p->l_ptrs;
			} else if (p->ptr < best->ptr)
				p = p->r_ptrs;
			else
				break;
		}

	if (size < best->size) {	/* shrink block */
		if (!next || next->used || next->broken) {
			if (best->size - size > MALLOC_ALIGN) {	/* do split */
				SPLIT_BLOCK(best, size);
			}
		} else {				/* just move border of next block */
			SHRINK_BLOCK(best, next, size);
		}
	} else if (next && !next->broken && !next->used) {	/* can expand */
		if (best->size + next->size > size + HUNK_MAXSIZE) {	/* shrink next free block */
			SHRINK_BLOCK(best, next, size);
		} else if (best->size + next->size >= size) {	/* combine blocks (eat next one) */
			FREE_MEM_DEL_BLOCK(next, p);
			COMBINE_BLOCKS(best, next);
		} else {				/* not enough memory in next block */
			mutex_unlock(&malloc_lock);
			return NULL;
		}
	} else {					/* no next block */
		mutex_unlock(&malloc_lock);
		return NULL;
	}
	mutex_unlock(&malloc_lock);
	return best->ptr;
}
#endif							/* L__realloc_no_move */

#ifdef L_realloc
void *realloc(void *ptr, size_t size)
{
	void *tmp;

	tmp = _realloc_no_move(ptr, size);

	if (!tmp) {
		Block_t *p, *best;

		mutex_lock(&malloc_lock);

		for (p = ptrs_root, best = NULL; p;) {
			if (p->ptr > (char *) ptr)
				p = p->l_ptrs;
			else {
				best = p;
				p = p->r_ptrs;
			}
		}

		if (!best || !best->used || best->ptr != (char *) ptr) {
			if (ptr) {
				Hunk_t *h;

				h = (Hunk_t *) PAGE_DOWNALIGNP(ptr);
				if (h->id == HUNK_ID) {
					mutex_unlock(&malloc_lock);
					if ((size >= HUNK_THRESHOLD && ALIGN(size) == h->size)
						|| size == h->size)
						return ptr;
					if ((tmp = malloc(size)) == NULL)
						return NULL;
					mutex_lock(&malloc_lock);
					memcpy(tmp, ptr, ((size < h->size) ? size : h->size));
					__hunk_free(ptr);
					mutex_unlock(&malloc_lock);
					return tmp;
				}
			}
			mutex_unlock(&malloc_lock);
			return malloc(size);
		}

		mutex_unlock(&malloc_lock);

		/* copy whole block */
		if ((tmp = malloc(size)) == NULL)
			return NULL;
		memcpy(tmp, ptr, ((size < best->size) ? size : best->size));

		mutex_lock(&malloc_lock);
		__bl_free(best);
		mutex_unlock(&malloc_lock);
	}
	return tmp;
}
#endif							/* L_realloc */

#ifdef L_calloc
void *calloc(size_t unit, size_t quantity)
{
	void *p;

	unit *= quantity;

	if ((p = malloc(unit)) == NULL)
		return NULL;
	memset(p, 0, unit);
	return p;
}
#endif							/* L_calloc */