| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| char *__strchrnul(const char *, int); |
| int __putenv(char *, size_t, char *); |
| |
| void __env_rm_add(char *old, char *new) |
| { |
| static char **env_alloced; |
| static size_t env_alloced_n; |
| for (size_t i=0; i < env_alloced_n; i++) |
| if (env_alloced[i] == old) { |
| env_alloced[i] = new; |
| free(old); |
| return; |
| } else if (!env_alloced[i] && new) { |
| env_alloced[i] = new; |
| new = 0; |
| } |
| if (!new) return; |
| char **t = realloc(env_alloced, sizeof *t * (env_alloced_n+1)); |
| if (!t) return; |
| (env_alloced = t)[env_alloced_n++] = new; |
| } |
| |
| int setenv(const char *var, const char *value, int overwrite) |
| { |
| char *s; |
| size_t l1, l2; |
| |
| if (!var || !(l1 = __strchrnul(var, '=') - var) || var[l1]) { |
| errno = EINVAL; |
| return -1; |
| } |
| if (!overwrite && getenv(var)) return 0; |
| |
| l2 = strlen(value); |
| s = malloc(l1+l2+2); |
| if (!s) return -1; |
| memcpy(s, var, l1); |
| s[l1] = '='; |
| memcpy(s+l1+1, value, l2+1); |
| return __putenv(s, l1, s); |
| } |