src/env/putenv.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <unistd.h>
   4
   5 static void dummy(char *old, char *new) {}
   6 weak_alias(dummy, __env_rm_add);
   7
   8 int __putenv(char *s, size_t l, char *r)
   9 {
  10         size_t i=0;
  11         if (__environ) {
  12                 for (char **e = __environ; *e; e++, i++)
  13                         if (!strncmp(s, *e, l+1)) {
  14                                 char *tmp = *e;
  15                                 *e = s;
  16                                 __env_rm_add(tmp, r);
  17                                 return 0;
  18                         }
  19         }
  20         static char **oldenv;
  21         char **newenv;
  22         if (__environ == oldenv) {
  23                 newenv = realloc(oldenv, sizeof *newenv * (i+2));
  24                 if (!newenv) goto oom;
  25         } else {
  26                 newenv = malloc(sizeof *newenv * (i+2));
  27                 if (!newenv) goto oom;
  28                 if (i) memcpy(newenv, __environ, sizeof *newenv * i);
  29                 free(oldenv);
  30         }
  31         newenv[i] = s;
  32         newenv[i+1] = 0;
  33         __environ = oldenv = newenv;
  34         if (r) __env_rm_add(0, r);
  35         return 0;
  36 oom:
  37         free(r);
  38         return -1;
  39 }
  40
  41 int putenv(char *s)
  42 {
  43         size_t l = __strchrnul(s, '=') - s;
  44         if (!l || !s[l]) return unsetenv(s);
  45         return __putenv(s, l, 0);
  46 }