src/env/putenv.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <unistd.h>
   4 #include "libc.h"
   5
   6 static void dummy(char *old, char *new) {}
   7 weak_alias(dummy, __env_rm_add);
   8
   9 int __putenv(char *s, size_t l, char *r)
  10 {
  11         size_t i=0;
  12         if (__environ) {
  13                 for (char **e = __environ; *e; e++, i++)
  14                         if (!strncmp(s, *e, l+1)) {
  15                                 char *tmp = *e;
  16                                 *e = s;
  17                                 __env_rm_add(tmp, r);
  18                                 return 0;
  19                         }
  20         }
  21         static char **oldenv;
  22         char **newenv;
  23         if (__environ == oldenv) {
  24                 newenv = realloc(oldenv, sizeof *newenv * (i+2));
  25                 if (!newenv) goto oom;
  26         } else {
  27                 newenv = malloc(sizeof *newenv * (i+2));
  28                 if (!newenv) goto oom;
  29                 if (i) memcpy(newenv, __environ, sizeof *newenv * i);
  30                 free(oldenv);
  31         }
  32         newenv[i] = s;
  33         newenv[i+1] = 0;
  34         __environ = oldenv = newenv;
  35         if (r) __env_rm_add(0, r);
  36         return 0;
  37 oom:
  38         free(r);
  39         return -1;
  40 }
  41
  42 int putenv(char *s)
  43 {
  44         size_t l = __strchrnul(s, '=') - s;
  45         if (!l || !s[l]) return unsetenv(s);
  46         return __putenv(s, l, 0);
  47 }