src/env/unsetenv.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <errno.h>
   4
   5 extern char **__environ;
   6 extern char **__env_map;
   7
   8 int unsetenv(const char *name)
   9 {
  10         int i, j;
  11         size_t l = strlen(name);
  12
  13         if (!*name || strchr(name, '=')) {
  14                 errno = EINVAL;
  15                 return -1;
  16         }
  17 again:
  18         for (i=0; __environ[i] && (memcmp(name, __environ[i], l) || __environ[i][l] != '='); i++);
  19         if (__environ[i]) {
  20                 if (__env_map) {
  21                         for (j=0; __env_map[j] && __env_map[j] != __environ[i]; j++);
  22                         free (__env_map[j]);
  23                         for (; __env_map[j]; j++)
  24                                 __env_map[j] = __env_map[j+1];
  25                 }
  26                 for (; __environ[i]; i++)
  27                         __environ[i] = __environ[i+1];
  28                 goto again;
  29         }
  30         return 0;
  31 }