lwip/src/core/mem.c

312 lines
8.7 KiB
C

/*
* Copyright (c) 2001-2003 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>
*
*/
/*-----------------------------------------------------------------------------------*/
/* mem.c
*
* Memory manager.
*
*/
/*-----------------------------------------------------------------------------------*/
#include "lwip/arch.h"
#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/sys.h"
#include "lwip/stats.h"
struct mem {
mem_size_t next, prev;
#if MEM_ALIGNMENT == 1
u8_t used;
#elif MEM_ALIGNMENT == 2
u16_t used;
#elif MEM_ALIGNMENT == 4
u32_t used;
#else
#error "unhandled MEM_ALIGNMENT size"
#endif /* MEM_ALIGNMENT */
};
static struct mem *ram_end;
static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT];
#define MIN_SIZE 12
#define SIZEOF_STRUCT_MEM MEM_ALIGN_SIZE(sizeof(struct mem))
/*#define SIZEOF_STRUCT_MEM (sizeof(struct mem) + \
(((sizeof(struct mem) % MEM_ALIGNMENT) == 0)? 0 : \
(4 - (sizeof(struct mem) % MEM_ALIGNMENT))))*/
static struct mem *lfree; /* pointer to the lowest free block */
static sys_sem_t mem_sem;
/*-----------------------------------------------------------------------------------*/
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", mem->next <= MEM_SIZE);
nmem = (struct mem *)&ram[mem->next];
if(mem != nmem && nmem->used == 0 && (u8_t *)nmem != (u8_t *)ram_end) {
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(lfree == mem) {
lfree = pmem;
}
pmem->next = mem->next;
((struct mem *)&ram[mem->next])->prev = (u8_t *)pmem - ram;
}
}
/*-----------------------------------------------------------------------------------*/
void
mem_init(void)
{
struct mem *mem;
memset(ram, 0, MEM_SIZE);
mem = (struct mem *)ram;
mem->next = MEM_SIZE;
mem->prev = 0;
mem->used = 0;
ram_end = (struct mem *)&ram[MEM_SIZE];
ram_end->used = 1;
ram_end->next = MEM_SIZE;
ram_end->prev = MEM_SIZE;
mem_sem = sys_sem_new(1);
lfree = (struct mem *)ram;
#ifdef MEM_STATS
lwip_stats.mem.avail = MEM_SIZE;
#endif /* MEM_STATS */
}
/*-----------------------------------------------------------------------------------*/
void
mem_free(void *rmem)
{
struct mem *mem;
if(rmem == NULL) {
return;
}
sys_sem_wait(mem_sem);
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) {
DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n"));
#ifdef MEM_STATS
++lwip_stats.mem.err;
#endif /* MEM_STATS */
return;
}
mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
LWIP_ASSERT("mem_free: mem->used", mem->used);
mem->used = 0;
if(mem < lfree) {
lfree = mem;
}
#ifdef MEM_STATS
lwip_stats.mem.used -= mem->next - ((u8_t *)mem - ram) - SIZEOF_STRUCT_MEM;
#endif /* MEM_STATS */
plug_holes(mem);
sys_sem_signal(mem_sem);
}
/*-----------------------------------------------------------------------------------*/
void *
mem_reallocm(void *rmem, mem_size_t newsize)
{
void *nmem;
nmem = mem_malloc(newsize);
if(nmem == NULL) {
return mem_realloc(rmem, newsize);
}
memcpy(nmem, rmem, newsize);
mem_free(rmem);
return nmem;
}
/*-----------------------------------------------------------------------------------*/
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. */
if((newsize % MEM_ALIGNMENT) != 0) {
newsize += MEM_ALIGNMENT - ((newsize + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);
}
if(newsize > MEM_SIZE) {
return NULL;
}
sys_sem_wait(mem_sem);
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) {
DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n"));
return rmem;
}
mem = (struct mem *)((u8_t *)rmem - SIZEOF_STRUCT_MEM);
ptr = (u8_t *)mem - ram;
size = mem->next - ptr - SIZEOF_STRUCT_MEM;
#ifdef MEM_STATS
lwip_stats.mem.used -= (size - newsize);
#endif /* MEM_STATS */
if(newsize + SIZEOF_STRUCT_MEM + MIN_SIZE < size) {
ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize;
mem2 = (struct mem *)&ram[ptr2];
mem2->used = 0;
mem2->next = mem->next;
mem2->prev = ptr;
mem->next = ptr2;
if(mem2->next != MEM_SIZE) {
((struct mem *)&ram[mem2->next])->prev = ptr2;
}
plug_holes(mem2);
}
sys_sem_signal(mem_sem);
return rmem;
}
/*-----------------------------------------------------------------------------------*/
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. */
if((size % MEM_ALIGNMENT) != 0) {
size += MEM_ALIGNMENT - ((size + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT);
}
if(size > MEM_SIZE) {
return NULL;
}
sys_sem_wait(mem_sem);
for(ptr = (u8_t *)lfree - ram; ptr < MEM_SIZE; ptr = ((struct mem *)&ram[ptr])->next) {
mem = (struct mem *)&ram[ptr];
if(!mem->used &&
mem->next - (ptr + SIZEOF_STRUCT_MEM) >= size + SIZEOF_STRUCT_MEM) {
ptr2 = ptr + SIZEOF_STRUCT_MEM + size;
mem2 = (struct mem *)&ram[ptr2];
mem2->prev = ptr;
mem2->next = mem->next;
mem->next = ptr2;
if(mem2->next != MEM_SIZE) {
((struct mem *)&ram[mem2->next])->prev = ptr2;
}
mem2->used = 0;
mem->used = 1;
#ifdef MEM_STATS
lwip_stats.mem.used += size;
/* if(lwip_stats.mem.max < lwip_stats.mem.used) {
lwip_stats.mem.max = lwip_stats.mem.used;
} */
if(lwip_stats.mem.max < ptr2) {
lwip_stats.mem.max = ptr2;
}
#endif /* MEM_STATS */
if(mem == lfree) {
/* Find next free block after mem */
while(lfree->used && lfree != ram_end) {
lfree = (struct mem *)&ram[lfree->next];
}
LWIP_ASSERT("mem_malloc: !lfree->used", !lfree->used);
}
sys_sem_signal(mem_sem);
LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.",
(u32_t)mem + SIZEOF_STRUCT_MEM + size <= (u32_t)ram_end);
LWIP_ASSERT("mem_malloc: allocated memory properly aligned.",
(unsigned long)((u8_t *)mem + SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0);
return (u8_t *)mem + SIZEOF_STRUCT_MEM;
}
}
DEBUGF(MEM_DEBUG | 2, ("mem_malloc: could not allocate %d bytes\n", (int)size));
#ifdef MEM_STATS
++lwip_stats.mem.err;
#endif /* MEM_STATS */
sys_sem_signal(mem_sem);
return NULL;
}
/*-----------------------------------------------------------------------------------*/