src/basic/alloc-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdint.h>
  21 #include <string.h>
  22
  23 #include "alloc-util.h"
  24 #include "macro.h"
  25 #include "util.h"
  26
  27 void* memdup(const void *p, size_t l) {
  28         void *ret;
  29
  30         assert(l == 0 || p);
  31
  32         ret = malloc(l);
  33         if (!ret)
  34                 return NULL;
  35
  36         memcpy(ret, p, l);
  37         return ret;
  38 }
  39
  40 void* memdup_suffix0(const void*p, size_t l) {
  41         void *ret;
  42
  43         assert(l == 0 || p);
  44
  45         /* The same as memdup() but place a safety NUL byte after the allocated memory */
  46
  47         ret = malloc(l + 1);
  48         if (!ret)
  49                 return NULL;
  50
  51         *((uint8_t*) mempcpy(ret, p, l)) = 0;
  52         return ret;
  53 }
  54
  55 void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size) {
  56         size_t a, newalloc;
  57         void *q;
  58
  59         assert(p);
  60         assert(allocated);
  61
  62         if (*allocated >= need)
  63                 return *p;
  64
  65         newalloc = MAX(need * 2, 64u / size);
  66         a = newalloc * size;
  67
  68         /* check for overflows */
  69         if (a < size * need)
  70                 return NULL;
  71
  72         q = realloc(*p, a);
  73         if (!q)
  74                 return NULL;
  75
  76         *p = q;
  77         *allocated = newalloc;
  78         return q;
  79 }
  80
  81 void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size) {
  82         size_t prev;
  83         uint8_t *q;
  84
  85         assert(p);
  86         assert(allocated);
  87
  88         prev = *allocated;
  89
  90         q = greedy_realloc(p, allocated, need, size);
  91         if (!q)
  92                 return NULL;
  93
  94         if (*allocated > prev)
  95                 memzero(q + prev * size, (*allocated - prev) * size);
  96
  97         return q;
  98 }