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/*
* Copyright (c) 2011 Alex Hornung <alex@alexhornung.com>.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDERS 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 <sys/types.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "tcplay.h"
struct safe_mem_hdr {
struct safe_mem_hdr *prev;
struct safe_mem_hdr *next;
struct safe_mem_tail *tail;
const char *file;
int line;
size_t alloc_sz;
char sig[8]; /* SAFEMEM */
};
struct safe_mem_tail {
char sig[8]; /* SAFEMEM */
};
static struct safe_mem_hdr *safe_mem_hdr_first = NULL;
void *
_alloc_safe_mem(size_t req_sz, const char *file, int line)
{
struct safe_mem_hdr *hdr, *hdrp;
struct safe_mem_tail *tail;
size_t alloc_sz;
char *mem, *user_mem;
alloc_sz = req_sz + sizeof(*hdr) + sizeof(*tail);
if ((mem = malloc(alloc_sz)) == NULL)
return NULL;
if (mlock(mem, alloc_sz) < 0) {
free(mem);
return NULL;
}
memset(mem, 0, alloc_sz);
hdr = (struct safe_mem_hdr *)mem;
tail = (struct safe_mem_tail *)(mem + alloc_sz - sizeof(*tail));
user_mem = mem + sizeof(*hdr);
strcpy(hdr->sig, "SAFEMEM");
strcpy(tail->sig, "SAFEMEM");
hdr->tail = tail;
hdr->alloc_sz = alloc_sz;
hdr->file = file;
hdr->line = line;
hdr->next = NULL;
if (safe_mem_hdr_first == NULL) {
safe_mem_hdr_first = hdr;
} else {
hdrp = safe_mem_hdr_first;
while (hdrp->next != NULL)
hdrp = hdrp->next;
hdr->prev = hdrp;
hdrp->next = hdr;
}
return user_mem;
}
void
_free_safe_mem(void *mem_ptr, const char *file, int line)
{
struct safe_mem_hdr *hdr;
struct safe_mem_tail *tail;
size_t alloc_sz;
char *mem = mem_ptr;
mem -= sizeof(*hdr);
hdr = (struct safe_mem_hdr *)mem;
tail = (struct safe_mem_tail *)(mem + hdr->alloc_sz - sizeof(*tail));
#ifdef DEBUG
fprintf(stderr, "freeing safe_mem (hdr): %#lx (%s:%d)\n",
(unsigned long)(void *)hdr, hdr->file, hdr->line);
#endif
if (hdr->alloc_sz == 0) {
fprintf(stderr, "BUG: double-free at %s:%d !!!\n", file, line);
return;
}
/* Integrity checks */
if ((memcmp(hdr->sig, "SAFEMEM\0", 8) != 0) ||
(memcmp(tail->sig, "SAFEMEM\0", 8) != 0)) {
fprintf(stderr, "BUG: safe_mem buffer under- or overflow at "
"%s:%d !!!\n", file, line);
return;
}
if (safe_mem_hdr_first == NULL) {
fprintf(stderr, "BUG: safe_mem list should not be empty at "
"%s:%d !!!\n", file, line);
return;
}
if (hdr->prev != NULL)
hdr->prev->next = hdr->next;
if (hdr->next != NULL)
hdr->next->prev = hdr->prev;
if (safe_mem_hdr_first == hdr)
safe_mem_hdr_first = hdr->next;
alloc_sz = hdr->alloc_sz;
memset(mem, 0xFF, alloc_sz);
memset(mem, 0, alloc_sz);
free(mem);
}
void
check_and_purge_safe_mem(void)
{
struct safe_mem_hdr *hdr;
char *mem;
#ifdef DEBUG
int ok;
#endif
if (safe_mem_hdr_first == NULL)
return;
hdr = safe_mem_hdr_first;
while ((hdr = safe_mem_hdr_first) != NULL) {
#ifdef DEBUG
if ((hdr->alloc_sz > 0) &&
(memcmp(hdr->sig, "SAFEMEM\0", 8) == 0) &&
(memcmp(hdr->tail->sig, "SAFEMEM\0", 8) == 0))
ok = 1;
else
ok = 0;
fprintf(stderr, "un-freed safe_mem: %#lx (%s:%d) [integrity=%s]\n",
(unsigned long)(void *)hdr, hdr->file, hdr->line,
ok? "ok" : "failed");
#endif
mem = (void *)hdr;
mem += sizeof(*hdr);
_free_safe_mem(mem, "check_and_purge_safe_mem", 0);
}
}
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