1#include <stdlib.h>
 2#include <string.h>
 3#include <unistd.h>
 4
 5static void dummy(char *old, char *new) {}
 6weak_alias(dummy, __env_rm_add);
 7
 8int __putenv(char *s, size_t l, char *r)
 9{
10#ifdef __wasilibc_unmodified_upstream // Lazy environment variable init.
11#else
12// This specialized header is included within the function body to arranges for
13// the environment variables to be lazily initialized. It redefined `__environ`,
14// so don't remove or reorder it with respect to other code.
15#include "wasi/libc-environ-compat.h"
16#endif
17	size_t i=0;
18	if (__environ) {
19		for (char **e = __environ; *e; e++, i++)
20			if (!strncmp(s, *e, l+1)) {
21				char *tmp = *e;
22				*e = s;
23				__env_rm_add(tmp, r);
24				return 0;
25			}
26	}
27	static char **oldenv;
28	char **newenv;
29	if (__environ == oldenv) {
30		newenv = realloc(oldenv, sizeof *newenv * (i+2));
31		if (!newenv) goto oom;
32	} else {
33		newenv = malloc(sizeof *newenv * (i+2));
34		if (!newenv) goto oom;
35		if (i) memcpy(newenv, __environ, sizeof *newenv * i);
36		free(oldenv);
37	}
38	newenv[i] = s;
39	newenv[i+1] = 0;
40	__environ = oldenv = newenv;
41	if (r) __env_rm_add(0, r);
42	return 0;
43oom:
44	free(r);
45	return -1;
46}
47
48int putenv(char *s)
49{
50	size_t l = __strchrnul(s, '=') - s;
51	if (!l || !s[l]) return unsetenv(s);
52	return __putenv(s, l, 0);
53}