File: [local] / prex-old / usr / lib / prex / malloc / malloc.c (download)
Revision 1.1.1.1 (vendor branch), Tue Jun 3 09:38:50 2008 UTC (16 years, 3 months ago) by nbrk
Branch: MAIN, KOHSUKE
CVS Tags: PREX_0_7_BASE, HEAD Branch point for: PREX_0_8_BASE
Changes since 1.1: +0 -0 lines
Yeah, this is an initial import of Prex, portable real-time microkernel
operating system. I wanna hack it for non-profit but fun, so let it in.
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/*
* Copyright (c) 2005-2007, Kohsuke Ohtani
* 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. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <prex/prex.h>
#include <sys/param.h>
#include <sys/syslog.h>
#include <string.h>
#include <errno.h>
#include "malloc.h"
#ifdef _REENTRANT
static mutex_t malloc_lock = MUTEX_INITIALIZER;
#endif
static struct header *more_core(size_t size);
static struct header free_list; /* start of free list */
static struct header *scan_head; /* start point to scan */
/*
* Simple memory allocator from K&R
*/
void *
malloc(size_t size)
{
struct header *p, *prev;
if (size == 0) /* sanity check */
return NULL;
size = ROUNDUP(size + sizeof(struct header));
MALLOC_LOCK();
if (scan_head == NULL) {
/* Initialize */
free_list.next = &free_list;
free_list.size = 0;
free_list.vm_size = 0;
scan_head = &free_list;
}
prev = scan_head;
for (p = prev->next;; prev = p, p = p->next) {
if (p->size >= size) { /* big enough */
if (p->size == size) /* exactly */
prev->next = p->next;
else { /* allocate tail end */
p->size -= size;
p = (struct header *)((u_long)p + p->size);
p->size = size;
p->vm_size = 0;
}
#ifdef CONFIG_MCHECK
p->magic = MALLOC_MAGIC;
#endif
scan_head = prev;
break;
}
if (p == scan_head) {
if ((p = more_core(size)) == NULL)
break;
}
}
MALLOC_UNLOCK();
if (p == NULL) {
#ifdef CONFIG_MCHECK
sys_panic("malloc: out of memory");
#endif
return NULL;
}
return (void *)(p + 1);
}
/*
* Create new block and insert it to the free list.
*/
static struct header *more_core(size_t size)
{
struct header *p, *prev;
size = PAGE_ALIGN(size);
if (vm_allocate(task_self(), (void *)&p, size, 1))
return NULL;
p->size = size;
p->vm_size = size;
/* Insert to free list */
for (prev = scan_head; !(p > prev && p < prev->next); prev = prev->next) {
if (prev >= prev->next && (p > prev || p < prev->next))
break;
}
p->next = prev->next;
prev->next = p;
scan_head = prev;
return prev;
}
void
free(void *addr)
{
struct header *p, *prev;
if (addr == NULL)
return;
MALLOC_LOCK();
p = (struct header *)addr - 1;
#ifdef CONFIG_MCHECK
if (p->magic != MALLOC_MAGIC)
sys_panic("free: invalid pointer");
p->magic = 0;
#endif
for (prev = scan_head; !(p > prev && p < prev->next); prev = prev->next) {
if (prev >= prev->next && (p > prev || p < prev->next))
break;
}
if ((prev->next->vm_size == 0) && /* join to upper block */
((u_long)p + p->size == (u_long)prev->next)) {
p->size += prev->next->size;
p->next = prev->next->next;
} else {
p->next = prev->next;
}
if ((p->vm_size == 0) && /* join to lower block */
((u_long)prev + prev->size == (u_long)p)) {
prev->size += p->size;
prev->next = p->next;
} else {
prev->next = p;
}
/* Deallocate pool */
if (p->size == p->vm_size) {
prev->next = p->next;
vm_free(task_self(), p);
}
scan_head = prev;
MALLOC_UNLOCK();
}
#ifdef CONFIG_MSTAT
void
mstat(void)
{
struct header *p;
syslog(LOG_INFO, "mstat: task=%x\n", task_self());
for (p = free_list.next; p != &free_list; p = p->next) {
syslog(LOG_INFO, "mstat: addr=%x size=%d next=%x\n", p, p->size, p->next);
}
}
#endif