src/env/putenv.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3
   4 extern char **__environ;
   5 char **__env_map;
   6
   7 int __putenv(char *s, int a)
   8 {
   9         int i=0, j=0;
  10         char *z = strchr(s, '=');
  11         char **newenv = 0;
  12         char **newmap = 0;
  13         static char **oldenv;
  14
  15         if (!z) return unsetenv(s);
  16         if (z==s) return -1;
  17         for (; __environ[i] && memcmp(s, __environ[i], z-s+1); i++);
  18         if (a) {
  19                 if (!__env_map) {
  20                         __env_map = calloc(2, sizeof(char *));
  21                         if (__env_map) __env_map[0] = s;
  22                 } else {
  23                         for (; __env_map[j] && __env_map[j] != __environ[i]; j++);
  24                         if (!__env_map[j]) {
  25                                 newmap = realloc(__env_map, sizeof(char *)*(j+2));
  26                                 if (newmap) {
  27                                         __env_map = newmap;
  28                                         __env_map[j] = s;
  29                                         __env_map[j+1] = NULL;
  30                                 }
  31                         } else {
  32                                 free(__env_map[j]);
  33                                 __env_map[j] = s;
  34                         }
  35                 }
  36         }
  37         if (!__environ[i]) {
  38                 newenv = malloc(sizeof(char *)*(i+2));
  39                 if (!newenv) {
  40                         if (a && __env_map) __env_map[j] = 0;
  41                         return -1;
  42                 }
  43                 memcpy(newenv, __environ, sizeof(char *)*i);
  44                 newenv[i] = s;
  45                 newenv[i+1] = 0;
  46                 __environ = newenv;
  47                 free(oldenv);
  48                 oldenv = __environ;
  49         }
  50
  51         __environ[i] = s;
  52         return 0;
  53 }
  54
  55 int putenv(char *s)
  56 {
  57         return __putenv(s, 0);
  58 }