/** | |
* @file | |
* Dynamic memory manager | |
* | |
* This is a lightweight replacement for the standard C library malloc(). | |
* | |
* If you want to use the standard C library malloc() instead, define | |
* MEM_LIBC_MALLOC to 1 in your lwipopts.h | |
* | |
* To let mem_malloc() use pools (prevents fragmentation and is much faster than | |
* a heap but might waste some memory), define MEM_USE_POOLS to 1, define | |
* MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list | |
* of pools like this (more pools can be added between _START and _END): | |
* | |
* Define three pools with sizes 256, 512, and 1512 bytes | |
* LWIP_MALLOC_MEMPOOL_START | |
* LWIP_MALLOC_MEMPOOL(20, 256) | |
* LWIP_MALLOC_MEMPOOL(10, 512) | |
* LWIP_MALLOC_MEMPOOL(5, 1512) | |
* LWIP_MALLOC_MEMPOOL_END | |
*/ | |
/* | |
* Copyright (c) 2001-2004 Swedish Institute of Computer Science. | |
* 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 author may not be used to endorse or promote products | |
* derived from this software without specific prior written permission. | |
* | |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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. | |
* | |
* This file is part of the lwIP TCP/IP stack. | |
* | |
* Author: Adam Dunkels <adam@sics.se> | |
* Simon Goldschmidt | |
* | |
*/ | |
#include "lwip/opt.h" | |
#if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */ | |
#include "lwip/def.h" | |
#include "lwip/mem.h" | |
#include "lwip/sys.h" | |
#include "lwip/stats.h" | |
#include <string.h> | |
#if MEM_USE_POOLS | |
/* lwIP head implemented with different sized pools */ | |
/** | |
* This structure is used to save the pool one element came from. | |
*/ | |
struct mem_helper | |
{ | |
memp_t poolnr; | |
}; | |
/** | |
* 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) | |
{ | |
struct mem_helper *element; | |
memp_t poolnr; | |
for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr++) { | |
/* is this pool big enough to hold an element of the required size | |
plus a struct mem_helper that saves the pool this element came from? */ | |
if ((size + sizeof(struct mem_helper)) <= memp_sizes[poolnr]) { | |
break; | |
} | |
} | |
if (poolnr > MEMP_POOL_LAST) { | |
LWIP_ASSERT("mem_malloc(): no pool is that big!", 0); | |
return NULL; | |
} | |
element = (struct mem_helper*)memp_malloc(poolnr); | |
if (element == NULL) { | |
/* No need to DEBUGF or ASSERT: This error is already | |
taken care of in memp.c */ | |
/** @todo: we could try a bigger pool if this one is empty! */ | |
return NULL; | |
} | |
/* save the pool number this element came from */ | |
element->poolnr = poolnr; | |
/* and return a pointer to the memory directly after the struct mem_helper */ | |
element++; | |
return element; | |
} | |
/** | |
* Free memory previously allocated by mem_malloc. Loads the pool number | |
* and calls memp_free with that pool number to put the element back into | |
* its pool | |
* | |
* @param rmem the memory element to free | |
*/ | |
void | |
mem_free(void *rmem) | |
{ | |
struct mem_helper *hmem = (struct mem_helper*)rmem; | |
LWIP_ASSERT("rmem != NULL", (rmem != NULL)); | |
LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem))); | |
/* get the original struct mem_helper */ | |
hmem--; | |
LWIP_ASSERT("hmem != NULL", (hmem != NULL)); | |
LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem))); | |
LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX)); | |
/* and put it in the pool we saved earlier */ | |
memp_free(hmem->poolnr, hmem); | |
} | |
#else /* MEM_USE_POOLS */ | |
/* lwIP replacement for your libc malloc() */ | |
/** | |
* The heap is made up as a list of structs of this type. | |
* This does not have to be aligned since for getting its size, | |
* we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes. | |
*/ | |
struct mem { | |
/** index (-> ram[next]) of the next struct */ | |
mem_size_t next; | |
/** index (-> ram[next]) of the next struct */ | |
mem_size_t prev; | |
/** 1: this area is used; 0: this area is unused */ | |
u8_t used; | |
}; | |
/** All allocated blocks will be MIN_SIZE bytes big, at least! | |
* MIN_SIZE can be overridden to suit your needs. Smaller values save space, | |
* larger values could prevent too small blocks to fragment the RAM too much. */ | |
#ifndef MIN_SIZE | |
#define MIN_SIZE 12 | |
#endif /* MIN_SIZE */ | |
/* some alignment macros: we define them here for better source code layout */ | |
#define MIN_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MIN_SIZE) | |
#define SIZEOF_STRUCT_MEM LWIP_MEM_ALIGN_SIZE(sizeof(struct mem)) | |
#define MEM_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MEM_SIZE) | |
/** the heap. we need one struct mem at the end and some room for alignment */ | |
static u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT]; | |
/** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */ | |
static u8_t *ram; | |
/** the last entry, always unused! */ | |
static struct mem *ram_end; | |
/** pointer to the lowest free block, this is used for faster search */ | |
static struct mem *lfree; | |
/** concurrent access protection */ | |
static sys_sem_t mem_sem; | |
/** | |
* "Plug holes" by combining adjacent empty struct mems. | |
* After this function is through, there should not exist | |
* one empty struct mem pointing to another empty struct mem. | |
* | |
* @param mem this points to a struct mem which just has been freed | |
* @internal this function is only called by mem_free() and mem_realloc() | |
* | |
* This assumes access to the heap is protected by the calling function | |
* already. | |
*/ | |
static void | |
plug_holes(struct mem *mem) | |
{ | |
struct mem *nmem; | |
struct mem *pmem; | |
LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *)mem >= ram); | |
LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *)mem < (u8_t *)ram_end); | |
LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0); | |
/* plug hole forward */ | |
LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", mem->next <= MEM_SIZE_ALIGNED); | |
nmem = (struct mem *)&ram[mem->next]; | |
if (mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) { | |
/* if mem->next is unused and not end of ram, combine mem and mem->next */ | |
if (lfree == nmem) { | |
lfree = mem; | |
} | |
mem->next = nmem->next; | |
((struct mem *)&ram[nmem->next])->prev = (u8_t *)mem - ram; | |
} | |
/* plug hole backward */ | |
pmem = (struct mem *)&ram[mem->prev]; | |
if (pmem != mem && pmem->used == 0) { | |
/* if mem->prev is unused, combine mem and mem->prev */ | |
if (lfree == mem) { | |
lfree = pmem; | |
} | |
pmem->next = mem->next; | |
((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram; | |
} | |
} | |
/** | |
* Zero the heap and initialize start, end and lowest-free | |
*/ | |
void | |
mem_init(void) | |
{ | |
struct mem *mem; | |
LWIP_ASSERT("Sanity check alignment", | |
(SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT-1)) == 0); | |
/* align the heap */ | |
ram = LWIP_MEM_ALIGN(ram_heap); | |
/* initialize the start of the heap */ | |
mem = (struct mem *)ram; | |
mem->next = MEM_SIZE_ALIGNED; | |
mem->prev = 0; | |
mem->used = 0; | |
/* initialize the end of the heap */ | |
ram_end = (struct mem *)&ram[MEM_SIZE_ALIGNED]; | |
ram_end->used = 1; | |
ram_end->next = MEM_SIZE_ALIGNED; | |
ram_end->prev = MEM_SIZE_ALIGNED; | |
mem_sem = sys_sem_new(1); | |
/* initialize the lowest-free pointer to the start of the heap */ | |
lfree = (struct mem *)ram; | |
#if MEM_STATS | |
lwip_stats.mem.avail = MEM_SIZE_ALIGNED; | |
#endif /* MEM_STATS */ | |
} | |
/** | |
* Put a struct mem back on the heap | |
* | |
* @param rmem is the data portion of a struct mem as returned by a previous | |
* call to mem_malloc() | |
*/ | |
void | |
mem_free(void *rmem) | |
{ | |
struct mem *mem; | |
if (rmem == NULL) { | |
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | 2, ("mem_free(p == NULL) was called.\n")); | |
return; | |
} | |
LWIP_ASSERT("mem_free: sanity check alignment", (((mem_ptr_t)rmem) & (MEM_ALIGNMENT-1)) == 0); | |
/* protect the heap from concurrent access */ | |
sys_arch_sem_wait(mem_sem, 0); | |
LWIP_ASSERT("mem_free: legal memory", (u8_t *)rmem >= (u8_t *)ram && | |
(u8_t *)rmem < (u8_t *)ram_end); | |
if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { | |
LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n")); | |
#if MEM_STATS | |
++lwip_stats.mem.err; | |
#endif /* MEM_STATS */ | |
sys_sem_signal(mem_sem); | |
return; | |
} | |
/* Get the corresponding struct mem ... */ | |
mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); | |
/* ... which has to be in a used state ... */ | |
LWIP_ASSERT("mem_free: mem->used", mem->used); | |
/* ... and is now unused. */ | |
mem->used = 0; | |
if (mem < lfree) { | |
/* the newly freed struct is now the lowest */ | |
lfree = mem; | |
} | |
#if MEM_STATS | |
lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram); | |
#endif /* MEM_STATS */ | |
/* finally, see if prev or next are free also */ | |
plug_holes(mem); | |
sys_sem_signal(mem_sem); | |
} | |
/** | |
* In contrast to its name, mem_realloc can only shrink memory, not expand it. | |
* Since the only use (for now) is in pbuf_realloc (which also can only shrink), | |
* this shouldn't be a problem! | |
* | |
* @param rmem pointer to memory allocated by mem_malloc the is to be shrinked | |
* @param newsize required size after shrinking (needs to be smaller than or | |
* equal to the previous size) | |
* @return for compatibility reasons: is always == rmem, at the moment | |
*/ | |
void * | |
mem_realloc(void *rmem, mem_size_t newsize) | |
{ | |
mem_size_t size; | |
mem_size_t ptr, ptr2; | |
struct mem *mem, *mem2; | |
/* Expand the size of the allocated memory region so that we can | |
adjust for alignment. */ | |
newsize = LWIP_MEM_ALIGN_SIZE(newsize); | |
if(newsize < MIN_SIZE_ALIGNED) { | |
/* every data block must be at least MIN_SIZE_ALIGNED long */ | |
newsize = MIN_SIZE_ALIGNED; | |
} | |
if (newsize > MEM_SIZE_ALIGNED) { | |
return NULL; | |
} | |
LWIP_ASSERT("mem_realloc: legal memory", (u8_t *)rmem >= (u8_t *)ram && | |
(u8_t *)rmem < (u8_t *)ram_end); | |
if ((u8_t *)rmem < (u8_t *)ram || (u8_t *)rmem >= (u8_t *)ram_end) { | |
LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n")); | |
return rmem; | |
} | |
/* Get the corresponding struct mem ... */ | |
mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM); | |
/* ... and its offset pointer */ | |
ptr = (u8_t *)mem - ram; | |
size = mem->next - ptr - SIZEOF_STRUCT_MEM; | |
LWIP_ASSERT("mem_realloc can only shrink memory", newsize <= size); | |
if (newsize > size) { | |
/* not supported */ | |
return NULL; | |
} | |
if (newsize == size) { | |
/* No change in size, simply return */ | |
return rmem; | |
} | |
/* protect the heap from concurrent access */ | |
sys_arch_sem_wait(mem_sem, 0); | |
#if MEM_STATS | |
lwip_stats.mem.used -= (size - newsize); | |
#endif /* MEM_STATS */ | |
mem2 = (struct mem *)&ram[mem->next]; | |
if(mem2->used == 0) { | |
/* The next struct is unused, we can simply move it at little */ | |
mem_size_t next; | |
/* remember the old next pointer */ | |
next = mem2->next; | |
/* create new struct mem which is moved directly after the shrinked mem */ | |
ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; | |
if (lfree == mem2) { | |
lfree = (struct mem *)&ram[ptr2]; | |
} | |
mem2 = (struct mem *)&ram[ptr2]; | |
mem2->used = 0; | |
/* restore the next pointer */ | |
mem2->next = next; | |
/* link it back to mem */ | |
mem2->prev = ptr; | |
/* link mem to it */ | |
mem->next = ptr2; | |
/* last thing to restore linked list: as we have moved mem2, | |
* let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not | |
* the end of the heap */ | |
if (mem2->next != MEM_SIZE_ALIGNED) { | |
((struct mem *)&ram[mem2->next])->prev = ptr2; | |
} | |
/* no need to plug holes, we've already done that */ | |
} else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) { | |
/* Next struct is used but there's room for another struct mem with | |
* at least MIN_SIZE_ALIGNED of data. | |
* Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem | |
* ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED'). | |
* @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 + newsize; | |
mem2 = (struct mem *)&ram[ptr2]; | |
if (mem2 < lfree) { | |
lfree = mem2; | |
} | |
mem2->used = 0; | |
mem2->next = mem->next; | |
mem2->prev = ptr; | |
mem->next = ptr2; | |
if (mem2->next != MEM_SIZE_ALIGNED) { | |
((struct mem *)&ram[mem2->next])->prev = ptr2; | |
} | |
/* the original mem->next is used, so no need to plug holes! */ | |
} | |
/* else { | |
next struct mem is used but size between mem and mem2 is not big enough | |
to create another struct mem | |
-> don't do anyhting. | |
-> the remaining space stays unused since it is too small | |
} */ | |
sys_sem_signal(mem_sem); | |
return rmem; | |
} | |
/** | |
* 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 (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_arch_sem_wait(mem_sem, 0); | |
/* Scan through the heap searching for a free block that is big enough, | |
* beginning with the lowest free block. | |
*/ | |
for (ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE_ALIGNED - size; | |
ptr = ((struct mem *)&ram[ptr])->next) { | |
mem = (struct mem *)&ram[ptr]; | |
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 *)&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 *)&ram[mem2->next])->prev = ptr2; | |
} | |
#if MEM_STATS | |
lwip_stats.mem.used += (size + SIZEOF_STRUCT_MEM); | |
if (lwip_stats.mem.max < lwip_stats.mem.used) { | |
lwip_stats.mem.max = lwip_stats.mem.used; | |
} | |
#endif /* MEM_STATS */ | |
} 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; | |
#if MEM_STATS | |
lwip_stats.mem.used += mem->next - ((u8_t *)mem - ram); | |
if (lwip_stats.mem.max < lwip_stats.mem.used) { | |
lwip_stats.mem.max = lwip_stats.mem.used; | |
} | |
#endif /* MEM_STATS */ | |
} | |
if (mem == lfree) { | |
/* Find next free block after mem and update lowest free pointer */ | |
while (lfree->used && lfree != ram_end) { | |
lfree = (struct mem *)&ram[lfree->next]; | |
} | |
LWIP_ASSERT("mem_malloc: !lfree->used", ((lfree == ram_end) || (!lfree->used))); | |
} | |
sys_sem_signal(mem_sem); | |
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.", | |
(unsigned long)((u8_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; | |
} | |
} | |
LWIP_DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size)); | |
#if MEM_STATS | |
++lwip_stats.mem.err; | |
#endif /* MEM_STATS */ | |
sys_sem_signal(mem_sem); | |
return NULL; | |
} | |
#endif /* MEM_USE_POOLS */ | |
/** | |
* Contiguously allocates enough space for count objects that are size bytes | |
* of memory each and returns a pointer to the allocated memory. | |
* | |
* The allocated memory is filled with bytes of value zero. | |
* | |
* @param count number of objects to allocate | |
* @param size size of the objects to allocate | |
* @return pointer to allocated memory / NULL pointer if there is an error | |
*/ | |
void *mem_calloc(mem_size_t count, mem_size_t size) | |
{ | |
void *p; | |
/* allocate 'count' objects of size 'size' */ | |
p = mem_malloc(count * size); | |
if (p) { | |
/* zero the memory */ | |
memset(p, 0, count * size); | |
} | |
return p; | |
} | |
#endif /* !MEM_LIBC_MALLOC */ |