cosmopolitan/libc/mem/putenv.c
2022-08-17 14:15:23 -07:00

134 lines
4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/strace.internal.h"
#include "libc/dce.h"
#include "libc/macros.internal.h"
#include "libc/mem/alg.h"
#include "libc/mem/internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
#define ToUpper(c) ((c) >= 'a' && (c) <= 'z' ? (c) - 'a' + 'A' : (c))
static bool once;
static size_t capacity;
static size_t GetEnvironLen(char **env) {
char **p = env;
while (*p) ++p;
return p - env;
}
static void RestoreOriginalEnvironment(char **envp) {
environ = envp;
}
static void PutEnvImplAtExit(void *p) {
free(p);
}
static void FreeEnviron(char **env) {
char **a;
for (a = env; *a; ++a) {
free(*a);
}
free(env);
}
static void GrowEnviron(void) {
size_t n, c;
char **a, **b, **p;
a = environ;
n = a ? GetEnvironLen(a) : 0;
c = MAX(16ul, n) << 1;
b = calloc(c, sizeof(char *));
if (a) {
for (p = b; *a;) {
*p++ = strdup(*a++);
}
}
__cxa_atexit(FreeEnviron, b, 0);
environ = b;
capacity = c;
}
int PutEnvImpl(char *s, bool overwrite) {
char *p;
unsigned i, namelen;
if (!once) {
__cxa_atexit(RestoreOriginalEnvironment, environ, 0);
GrowEnviron();
once = true;
} else if (!environ) {
GrowEnviron();
}
for (p = s; *p && *p != '='; ++p) {
if (IsWindows()) {
*p = ToUpper(*p);
}
}
if (*p != '=') goto Fail;
namelen = p + 1 - s;
for (i = 0; environ[i]; ++i) {
if (!strncmp(environ[i], s, namelen)) {
if (!overwrite) {
free(s);
return 0;
}
goto Replace;
}
}
if (i + 1 >= capacity) {
GrowEnviron();
}
environ[i + 1] = 0;
Replace:
__cxa_atexit(PutEnvImplAtExit, environ[i], 0);
environ[i] = s;
return 0;
Fail:
free(s);
return einval();
}
static void UnsetenvFree(void *p) {
free(p);
}
/* weakly called by unsetenv() when removing a pointer */
void __freeenv(void *p) {
if (once) {
__cxa_atexit(UnsetenvFree, p, 0);
}
}
/**
* Emplaces environment key=value.
*
* @return 0 on success or non-zero on error
* @see setenv(), getenv()
*/
int putenv(char *s) {
int rc;
rc = PutEnvImpl(strdup(s), true);
STRACE("putenv(%#s) → %d", s, rc);
return rc;
}