toaruos/libc/stdlib/putenv.c
2018-05-02 19:25:03 +09:00

75 lines
1.2 KiB
C

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
extern char ** environ;
extern int _environ_size;
static int why_no_strnstr(char * a, char * b, int n) {
for (int i = 0; (i < n) && (a[i]) && (b[i]); ++i) {
if (a[i] != b[i]) {
return 1;
}
}
return 0;
}
int putenv(char * string) {
if (_environ_size == 0) {
/* Find actual size */
int size = 0;
char ** tmp = environ;
while (*tmp) {
size++;
tmp++;
}
/* Multiply by two */
_environ_size = size * 2;
char ** new_environ = malloc(sizeof(char*) * _environ_size);
int i = 0;
while (environ[i]) {
new_environ[i] = environ[i];
i++;
}
while (i < _environ_size) {
new_environ[i] = NULL;
i++;
}
environ = new_environ;
}
char name[strlen(string)];
strcpy(name, string);
char * c = strchr(name, '=');
if (!c) {
return 1;
}
*c = NULL;
int s = strlen(name);
int i;
for (i = 0; environ[i]; ++i) {
if (!why_no_strnstr(name, environ[i], s)) {
environ[i] = string;
return 0;
}
}
/* Not found */
if (i >= _environ_size) {
environ = realloc(environ, _environ_size * 2);
for (int i = _environ_size; i < _environ_size * 2; ++i) {
environ[i] = NULL;
}
_environ_size *= 2;
}
environ[i] = string;
return 0;
}