/**
* Allocate memory: determine the smallest pool that is big enough
* to contain an element of 'size' and get an element from that pool.
*
* @param size the size in bytes of the memory needed
* @return a pointer to the allocated memory or NULL if the pool is empty
*/
void *
mem_malloc(mem_size_t size)
{
void *ret;
struct memp_malloc_helper *element;
memp_t poolnr;
mem_size_t required_size = size + LWIP_MEM_ALIGN_SIZE(sizeof(struct memp_malloc_helper));
for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr = (memp_t)(poolnr + 1)) {
#if MEM_USE_POOLS_TRY_BIGGER_POOL
again:
#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */
/* is this pool big enough to hold an element of the required size
plus a struct memp_malloc_helper that saves the pool this element came from? */
if (required_size <= memp_pools[poolnr]->size) {
break;
}
}
if (poolnr > MEMP_POOL_LAST) {
LWIP_ASSERT("mem_malloc(): no pool is that big!", 0);
MEM_STATS_INC(err);
return NULL;
}
element = (struct memp_malloc_helper*)memp_malloc(poolnr);
if (element == NULL) {
/* No need to DEBUGF or ASSERT: This error is already
taken care of in memp.c */
#if MEM_USE_POOLS_TRY_BIGGER_POOL
/** Try a bigger pool if this one is empty! */
if (poolnr < MEMP_POOL_LAST) {
poolnr++;
goto again;
}
#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */
MEM_STATS_INC(err);
return NULL;
}
/* save the pool number this element came from */
element->poolnr = poolnr;
/* and return a pointer to the memory directly after the struct memp_malloc_helper */
ret = (u8_t*)element + LWIP_MEM_ALIGN_SIZE(sizeof(struct memp_malloc_helper));
#if MEMP_OVERFLOW_CHECK || (LWIP_STATS && MEM_STATS)
/* truncating to u16_t is safe because struct memp_desc::size is u16_t */
element->size = (u16_t)size;
MEM_STATS_INC_USED(used, element->size);
#endif /* MEMP_OVERFLOW_CHECK || (LWIP_STATS && MEM_STATS) */
#if MEMP_OVERFLOW_CHECK
/* initialize unused memory (diff between requested size and selected pool's size) */
memset((u8_t*)ret + size, 0xcd, memp_pools[poolnr]->size - size);
#endif /* MEMP_OVERFLOW_CHECK */
return ret;
}
/**
* Allocate a block of memory with a minimum of 'size' bytes.
*
* @param size is the minimum size of the requested block in bytes.
* @return pointer to allocated memory or NULL if no free memory was found.
*
* Note that the returned value must always be aligned (as defined by MEM_ALIGNMENT).
*/
void *
mem_malloc(mem_size_t size)
{
void* ret = mem_clib_malloc(size + MEM_LIBC_STATSHELPER_SIZE);
if (ret == NULL) {
MEM_STATS_INC(err);
} else {
LWIP_ASSERT("malloc() must return aligned memory", LWIP_MEM_ALIGN(ret) == ret);
#if LWIP_STATS && MEM_STATS
*(mem_size_t*)ret = size;
ret = (u8_t*)ret + MEM_LIBC_STATSHELPER_SIZE;
MEM_STATS_INC_USED(used, size);
#endif
}
return ret;
}
/**
* Adam's mem_malloc() plus solution for bug #17922
* Allocate a block of memory with a minimum of 'size' bytes.
*
* @param size is the minimum size of the requested block in bytes.
* @return pointer to allocated memory or NULL if no free memory was found.
*
* Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT).
*/
void *
mem_malloc(mem_size_t size)
{
mem_size_t ptr, ptr2;
struct mem *mem, *mem2;
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
u8_t local_mem_free_count = 0;
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
LWIP_MEM_ALLOC_DECL_PROTECT();
if (size == 0) {
return NULL;
}
/* Expand the size of the allocated memory region so that we can
adjust for alignment. */
size = LWIP_MEM_ALIGN_SIZE(size);
if(size < MIN_SIZE_ALIGNED) {
/* every data block must be at least MIN_SIZE_ALIGNED long */
size = MIN_SIZE_ALIGNED;
}
if (size > MEM_SIZE_ALIGNED) {
return NULL;
}
/* protect the heap from concurrent access */
sys_mutex_lock(&mem_mutex);
LWIP_MEM_ALLOC_PROTECT();
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
/* run as long as a mem_free disturbed mem_malloc or mem_trim */
do {
local_mem_free_count = 0;
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
/* Scan through the heap searching for a free block that is big enough,
* beginning with the lowest free block.
*/
for (ptr = (mem_size_t)((u8_t *)lfree - ram); ptr < MEM_SIZE_ALIGNED - size;
ptr = ((struct mem *)(void *)&ram[ptr])->next) {
mem = (struct mem *)(void *)&ram[ptr];
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
mem_free_count = 0;
LWIP_MEM_ALLOC_UNPROTECT();
/* allow mem_free or mem_trim to run */
LWIP_MEM_ALLOC_PROTECT();
if (mem_free_count != 0) {
/* If mem_free or mem_trim have run, we have to restart since they
could have altered our current struct mem. */
local_mem_free_count = 1;
break;
}
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
if ((!mem->used) &&
(mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) {
/* mem is not used and at least perfect fit is possible:
* mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */
if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) {
/* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing
* at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem')
* -> split large block, create empty remainder,
* remainder must be large enough to contain MIN_SIZE_ALIGNED data: if
* mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size,
* struct mem would fit in but no data between mem2 and mem2->next
* @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty
* region that couldn't hold data, but when mem->next gets freed,
* the 2 regions would be combined, resulting in more free memory
*/
ptr2 = ptr + SIZEOF_STRUCT_MEM + size;
/* create mem2 struct */
mem2 = (struct mem *)(void *)&ram[ptr2];
mem2->used = 0;
mem2->next = mem->next;
mem2->prev = ptr;
/* and insert it between mem and mem->next */
mem->next = ptr2;
mem->used = 1;
if (mem2->next != MEM_SIZE_ALIGNED) {
((struct mem *)(void *)&ram[mem2->next])->prev = ptr2;
}
MEM_STATS_INC_USED(used, (size + SIZEOF_STRUCT_MEM));
} else {
/* (a mem2 struct does no fit into the user data space of mem and mem->next will always
* be used at this point: if not we have 2 unused structs in a row, plug_holes should have
* take care of this).
* -> near fit or excact fit: do not split, no mem2 creation
* also can't move mem->next directly behind mem, since mem->next
* will always be used at this point!
*/
mem->used = 1;
MEM_STATS_INC_USED(used, mem->next - (mem_size_t)((u8_t *)mem - ram));
}
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
mem_malloc_adjust_lfree:
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
if (mem == lfree) {
struct mem *cur = lfree;
/* Find next free block after mem and update lowest free pointer */
while (cur->used && cur != ram_end) {
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
mem_free_count = 0;
LWIP_MEM_ALLOC_UNPROTECT();
/* prevent high interrupt latency... */
LWIP_MEM_ALLOC_PROTECT();
if (mem_free_count != 0) {
/* If mem_free or mem_trim have run, we have to restart since they
could have altered our current struct mem or lfree. */
goto mem_malloc_adjust_lfree;
}
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
cur = (struct mem *)(void *)&ram[cur->next];
}
lfree = cur;
LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used)));
}
LWIP_MEM_ALLOC_UNPROTECT();
sys_mutex_unlock(&mem_mutex);
LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.",
(mem_ptr_t)mem + SIZEOF_STRUCT_MEM + size <= (mem_ptr_t)ram_end);
LWIP_ASSERT("mem_malloc: allocated memory properly aligned.",
((mem_ptr_t)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);
LWIP_ASSERT("mem_malloc: sanity check alignment",
(((mem_ptr_t)mem) & (MEM_ALIGNMENT-1)) == 0);
return (u8_t *)mem + SIZEOF_STRUCT_MEM;
}
}
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
/* if we got interrupted by a mem_free, try again */
} while(local_mem_free_count != 0);
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size));
MEM_STATS_INC(err);
LWIP_MEM_ALLOC_UNPROTECT();
sys_mutex_unlock(&mem_mutex);
return NULL;
}