Systemd/src/basic/alloc-util.c
Lennart Poettering c165d97d16 alloc-util: add new helpers memdup_suffix0() and newdup_suffix0()
These are similar to memdup() and newdup(), but reserve one extra NUL
byte at the end of the new allocation and initialize it. It's useful
when copying out data from fixed size character arrays where NUL
termination can't be assumed.
2017-07-31 18:20:28 +02:00

99 lines
2.3 KiB
C

/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdint.h>
#include <string.h>
#include "alloc-util.h"
#include "macro.h"
#include "util.h"
void* memdup(const void *p, size_t l) {
void *ret;
assert(l == 0 || p);
ret = malloc(l);
if (!ret)
return NULL;
memcpy(ret, p, l);
return ret;
}
void* memdup_suffix0(const void*p, size_t l) {
void *ret;
assert(l == 0 || p);
/* The same as memdup() but place a safety NUL byte after the allocated memory */
ret = malloc(l + 1);
if (!ret)
return NULL;
*((uint8_t*) mempcpy(ret, p, l)) = 0;
return ret;
}
void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size) {
size_t a, newalloc;
void *q;
assert(p);
assert(allocated);
if (*allocated >= need)
return *p;
newalloc = MAX(need * 2, 64u / size);
a = newalloc * size;
/* check for overflows */
if (a < size * need)
return NULL;
q = realloc(*p, a);
if (!q)
return NULL;
*p = q;
*allocated = newalloc;
return q;
}
void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size) {
size_t prev;
uint8_t *q;
assert(p);
assert(allocated);
prev = *allocated;
q = greedy_realloc(p, allocated, need, size);
if (!q)
return NULL;
if (*allocated > prev)
memzero(q + prev * size, (*allocated - prev) * size);
return q;
}