BadVPN – Rev 1
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/**
* @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
* MEMP_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"
#include "lwip/mem.h"
#include "lwip/def.h"
#include "lwip/sys.h"
#include "lwip/stats.h"
#include "lwip/err.h"
#include <string.h>
#if MEM_LIBC_MALLOC
#include <stdlib.h> /* for malloc()/free() */
#endif
/* This is overridable for tests only... */
#ifndef LWIP_MEM_ILLEGAL_FREE
#define LWIP_MEM_ILLEGAL_FREE(msg) LWIP_ASSERT(msg, 0)
#endif
#define MEM_STATS_INC_LOCKED(x) SYS_ARCH_LOCKED(MEM_STATS_INC(x))
#define MEM_STATS_INC_USED_LOCKED(x, y) SYS_ARCH_LOCKED(MEM_STATS_INC_USED(x, y))
#define MEM_STATS_DEC_USED_LOCKED(x, y) SYS_ARCH_LOCKED(MEM_STATS_DEC_USED(x, y))
#if MEM_LIBC_MALLOC || MEM_USE_POOLS
/** mem_init is not used when using pools instead of a heap or using
* C library malloc().
*/
void
mem_init(void)
{
}
/** mem_trim is not used when using pools instead of a heap or using
* C library malloc(): we can't free part of a pool element and the stack
* support mem_trim() to return a different pointer
*/
void *
mem_trim(void *mem, mem_size_t size)
{
LWIP_UNUSED_ARG(size);
return mem;
}
#endif /* MEM_LIBC_MALLOC || MEM_USE_POOLS */
#if MEM_LIBC_MALLOC
/* lwIP heap implemented using C library malloc() */
/* in case C library malloc() needs extra protection,
* allow these defines to be overridden.
*/
#ifndef mem_clib_free
#define mem_clib_free free
#endif
#ifndef mem_clib_malloc
#define mem_clib_malloc malloc
#endif
#ifndef mem_clib_calloc
#define mem_clib_calloc calloc
#endif
#if LWIP_STATS && MEM_STATS
#define MEM_LIBC_STATSHELPER_SIZE LWIP_MEM_ALIGN_SIZE(sizeof(mem_size_t))
#else
#define MEM_LIBC_STATSHELPER_SIZE 0
#endif
/**
* 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_LOCKED(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_LOCKED(used, size);
#endif
}
return ret;
}
/** Put memory back on the heap
*
* @param rmem is the pointer as returned by a previous call to mem_malloc()
*/
void
mem_free(void *rmem)
{
LWIP_ASSERT("rmem != NULL", (rmem != NULL));
LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem)));
#if LWIP_STATS && MEM_STATS
rmem = (u8_t *)rmem - MEM_LIBC_STATSHELPER_SIZE;
MEM_STATS_DEC_USED_LOCKED(used, *(mem_size_t *)rmem);
#endif
mem_clib_free(rmem);
}
#elif MEM_USE_POOLS
/* lwIP heap implemented with different sized pools */
/**
* 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 = NULL;
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)) {
/* 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) {
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) {
continue;
}
#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */
MEM_STATS_INC_LOCKED(err);
return NULL;
}
break;
}
}
if (poolnr > MEMP_POOL_LAST) {
LWIP_ASSERT("mem_malloc(): no pool is that big!", 0);
MEM_STATS_INC_LOCKED(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_LOCKED(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;
}
/**
* 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 memp_malloc_helper *hmem;
LWIP_ASSERT("rmem != NULL", (rmem != NULL));
LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem)));
/* get the original struct memp_malloc_helper */
/* cast through void* to get rid of alignment warnings */
hmem = (struct memp_malloc_helper *)(void *)((u8_t *)rmem - LWIP_MEM_ALIGN_SIZE(sizeof(struct memp_malloc_helper)));
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));
MEM_STATS_DEC_USED_LOCKED(used, hmem->size);
#if MEMP_OVERFLOW_CHECK
{
u16_t i;
LWIP_ASSERT("MEM_USE_POOLS: invalid chunk size",
hmem->size <= memp_pools[hmem->poolnr]->size);
/* check that unused memory remained untouched (diff between requested size and selected pool's size) */
for (i = hmem->size; i < memp_pools[hmem->poolnr]->size; i++) {
u8_t data = *((u8_t *)rmem + i);
LWIP_ASSERT("MEM_USE_POOLS: mem overflow detected", data == 0xcd);
}
}
#endif /* MEMP_OVERFLOW_CHECK */
/* 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 aligns.
*/
struct mem {
/** index (-> ram[next]) of the next struct */
mem_size_t next;
/** index (-> ram[prev]) of the previous 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)
/** If you want to relocate the heap to external memory, simply define
* LWIP_RAM_HEAP_POINTER as a void-pointer to that location.
* If so, make sure the memory at that location is big enough (see below on
* how that space is calculated). */
#ifndef LWIP_RAM_HEAP_POINTER
/** the heap. we need one struct mem at the end and some room for alignment */
LWIP_DECLARE_MEMORY_ALIGNED(ram_heap, MEM_SIZE_ALIGNED + (2U * SIZEOF_STRUCT_MEM));
#define LWIP_RAM_HEAP_POINTER ram_heap
#endif /* LWIP_RAM_HEAP_POINTER */
/** 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 */
#if !NO_SYS
static sys_mutex_t mem_mutex;
#endif
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
static volatile u8_t mem_free_count;
/* Allow mem_free from other (e.g. interrupt) context */
#define LWIP_MEM_FREE_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_free)
#define LWIP_MEM_FREE_PROTECT() SYS_ARCH_PROTECT(lev_free)
#define LWIP_MEM_FREE_UNPROTECT() SYS_ARCH_UNPROTECT(lev_free)
#define LWIP_MEM_ALLOC_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_alloc)
#define LWIP_MEM_ALLOC_PROTECT() SYS_ARCH_PROTECT(lev_alloc)
#define LWIP_MEM_ALLOC_UNPROTECT() SYS_ARCH_UNPROTECT(lev_alloc)
#else /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
/* Protect the heap only by using a mutex */
#define LWIP_MEM_FREE_DECL_PROTECT()
#define LWIP_MEM_FREE_PROTECT() sys_mutex_lock(&mem_mutex)
#define LWIP_MEM_FREE_UNPROTECT() sys_mutex_unlock(&mem_mutex)
/* mem_malloc is protected using mutex AND LWIP_MEM_ALLOC_PROTECT */
#define LWIP_MEM_ALLOC_DECL_PROTECT()
#define LWIP_MEM_ALLOC_PROTECT()
#define LWIP_MEM_ALLOC_UNPROTECT()
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
/**
* "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_trim()
*
* 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 *)(void *)&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 *)(void *)&ram[nmem->next])->prev = (mem_size_t)((u8_t *)mem - ram);
}
/* plug hole backward */
pmem = (struct mem *)(void *)&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 *)(void *)&ram[mem->next])->prev = (mem_size_t)((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 = (u8_t *)LWIP_MEM_ALIGN(LWIP_RAM_HEAP_POINTER);
/* initialize the start of the heap */
mem = (struct mem *)(void *)ram;
mem->next = MEM_SIZE_ALIGNED;
mem->prev = 0;
mem->used = 0;
/* initialize the end of the heap */
ram_end = (struct mem *)(void *)&ram[MEM_SIZE_ALIGNED];
ram_end->used = 1;
ram_end->next = MEM_SIZE_ALIGNED;
ram_end->prev = MEM_SIZE_ALIGNED;
/* initialize the lowest-free pointer to the start of the heap */
lfree = (struct mem *)(void *)ram;
MEM_STATS_AVAIL(avail, MEM_SIZE_ALIGNED);
if (sys_mutex_new(&mem_mutex) != ERR_OK) {
LWIP_ASSERT("failed to create mem_mutex", 0);
}
}
/* Check if a struct mem is correctly linked.
* If not, double-free is a possible reason.
*/
static int
mem_link_valid(struct mem *mem)
{
struct mem *nmem, *pmem;
mem_size_t rmem_idx;
rmem_idx = (mem_size_t)((u8_t *)mem - ram);
nmem = (struct mem *)(void *)&ram[mem->next];
pmem = (struct mem *)(void *)&ram[mem->prev];
if ((mem->next > MEM_SIZE_ALIGNED) || (mem->prev > MEM_SIZE_ALIGNED) ||
((mem->prev != rmem_idx) && (pmem->next != rmem_idx)) ||
((nmem != ram_end) && (nmem->prev != rmem_idx))) {
return 0;
}
return 1;
}
/**
* 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;
LWIP_MEM_FREE_DECL_PROTECT();
if (rmem == NULL) {
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("mem_free(p == NULL) was called.\n"));
return;
}
if ((((mem_ptr_t)rmem) & (MEM_ALIGNMENT - 1)) != 0) {
LWIP_MEM_ILLEGAL_FREE("mem_free: sanity check alignment");
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: sanity check alignment\n"));
/* protect mem stats from concurrent access */
MEM_STATS_INC_LOCKED(illegal);
return;
}
/* Get the corresponding struct mem: */
/* cast through void* to get rid of alignment warnings */
mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
if ((u8_t *)mem < ram || (u8_t *)rmem + MIN_SIZE_ALIGNED > (u8_t *)ram_end) {
LWIP_MEM_ILLEGAL_FREE("mem_free: illegal memory");
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory\n"));
/* protect mem stats from concurrent access */
MEM_STATS_INC_LOCKED(illegal);
return;
}
/* protect the heap from concurrent access */
LWIP_MEM_FREE_PROTECT();
/* mem has to be in a used state */
if (!mem->used) {
LWIP_MEM_ILLEGAL_FREE("mem_free: illegal memory: double free");
LWIP_MEM_FREE_UNPROTECT();
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory: double free?\n"));
/* protect mem stats from concurrent access */
MEM_STATS_INC_LOCKED(illegal);
return;
}
if (!mem_link_valid(mem)) {
LWIP_MEM_ILLEGAL_FREE("mem_free: illegal memory: non-linked: double free");
LWIP_MEM_FREE_UNPROTECT();
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("mem_free: illegal memory: non-linked: double free?\n"));
/* protect mem stats from concurrent access */
MEM_STATS_INC_LOCKED(illegal);
return;
}
/* mem is now unused. */
mem->used = 0;
if (mem < lfree) {
/* the newly freed struct is now the lowest */
lfree = mem;
}
MEM_STATS_DEC_USED(used, mem->next - (mem_size_t)(((u8_t *)mem - ram)));
/* finally, see if prev or next are free also */
plug_holes(mem);
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
mem_free_count = 1;
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
LWIP_MEM_FREE_UNPROTECT();
}
/**
* Shrink memory returned by mem_malloc().
*
* @param rmem pointer to memory allocated by mem_malloc the is to be shrinked
* @param new_size 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
* or NULL if newsize is > old size, in which case rmem is NOT touched
* or freed!
*/
void *
mem_trim(void *rmem, mem_size_t new_size)
{
mem_size_t size, newsize;
mem_size_t ptr, ptr2;
struct mem *mem, *mem2;
/* use the FREE_PROTECT here: it protects with sem OR SYS_ARCH_PROTECT */
LWIP_MEM_FREE_DECL_PROTECT();
/* Expand the size of the allocated memory region so that we can
adjust for alignment. */
newsize = (mem_size_t)LWIP_MEM_ALIGN_SIZE(new_size);
if ((newsize > MEM_SIZE_ALIGNED) || (newsize < new_size)) {
return NULL;
}
if (newsize < MIN_SIZE_ALIGNED) {
/* every data block must be at least MIN_SIZE_ALIGNED long */
newsize = MIN_SIZE_ALIGNED;
}
LWIP_ASSERT("mem_trim: 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 | LWIP_DBG_LEVEL_SEVERE, ("mem_trim: illegal memory\n"));
/* protect mem stats from concurrent access */
MEM_STATS_INC_LOCKED(illegal);
return rmem;
}
/* Get the corresponding struct mem ... */
/* cast through void* to get rid of alignment warnings */
mem = (struct mem *)(void *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
/* ... and its offset pointer */
ptr = (mem_size_t)((u8_t *)mem - ram);
size = (mem_size_t)((mem_size_t)(mem->next - ptr) - SIZEOF_STRUCT_MEM);
LWIP_ASSERT("mem_trim 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 */
LWIP_MEM_FREE_PROTECT();
mem2 = (struct mem *)(void *)&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 = (mem_size_t)(ptr + SIZEOF_STRUCT_MEM + newsize);
if (lfree == mem2) {
lfree = (struct mem *)(void *)&ram[ptr2];
}
mem2 = (struct mem *)(void *)&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 *)(void *)&ram[mem2->next])->prev = ptr2;
}
MEM_STATS_DEC_USED(used, (size - newsize));
/* 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 = (mem_size_t)(ptr + SIZEOF_STRUCT_MEM + newsize);
mem2 = (struct mem *)(void *)&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 *)(void *)&ram[mem2->next])->prev = ptr2;
}
MEM_STATS_DEC_USED(used, (size - newsize));
/* 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
} */
#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
mem_free_count = 1;
#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */
LWIP_MEM_FREE_UNPROTECT();
return rmem;
}
/**
* Allocate a block of memory with a minimum of 'size' bytes.
*
* @param size_in 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_in)
{
mem_size_t ptr, ptr2, size;
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_in == 0) {
return NULL;
}
/* Expand the size of the allocated memory region so that we can
adjust for alignment. */
size = (mem_size_t)LWIP_MEM_ALIGN_SIZE(size_in);
if ((size > MEM_SIZE_ALIGNED) ||
(size < size_in)) {
return NULL;
}
if (size < MIN_SIZE_ALIGNED) {
/* every data block must be at least MIN_SIZE_ALIGNED long */
size = MIN_SIZE_ALIGNED;
}
/* 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 = (mem_size_t)(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 exact 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 */
MEM_STATS_INC(err);
LWIP_MEM_ALLOC_UNPROTECT();
sys_mutex_unlock(&mem_mutex);
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_malloc: could not allocate %"S16_F" bytes\n", (s16_t)size));
return NULL;
}
#endif /* MEM_USE_POOLS */
#if MEM_LIBC_MALLOC && (!LWIP_STATS || !MEM_STATS)
void *
mem_calloc(mem_size_t count, mem_size_t size)
{
return mem_clib_calloc(count, size);
}
#else /* MEM_LIBC_MALLOC && (!LWIP_STATS || !MEM_STATS) */
/**
* 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;
size_t alloc_size = (size_t)count * (size_t)size;
if ((size_t)(mem_size_t)alloc_size != alloc_size) {
LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("mem_calloc: could not allocate %"SZT_F" bytes\n", alloc_size));
return NULL;
}
/* allocate 'count' objects of size 'size' */
p = mem_malloc((mem_size_t)alloc_size);
if (p) {
/* zero the memory */
memset(p, 0, alloc_size);
}
return p;
}
#endif /* MEM_LIBC_MALLOC && (!LWIP_STATS || !MEM_STATS) */