cosmopolitan/libc/mem/putenv.c

77 lines
3.2 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 │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/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"
static size_t g_environcap;
int PutEnvImpl(char *string, bool overwrite) {
if (!environ) {
g_environcap = 0;
if ((environ = calloc(8, sizeof(char *)))) {
g_environcap = 8;
}
}
char *equalp = strchr(string, '=');
if (!equalp) return einval();
unsigned namelen = equalp + 1 - string;
unsigned i;
for (i = 0; environ[i]; ++i) {
if (strncmp(environ[i], string, namelen) == 0) {
if (!overwrite) {
free_s(&string);
return 0;
}
goto replace;
}
}
if (i + 1 >= g_environcap) {
if (!g_environcap) g_environcap = i + 1;
if (!grow(&environ, &g_environcap, sizeof(char *), 0)) {
free_s(&string);
return -1;
}
}
environ[i + 1] = NULL;
replace:
free_s(&environ[i]);
environ[i] = string;
return 0;
}
/**
* Emplaces environment key=value.
* @see setenv(), getenv()
*/
int putenv(char *string) { return PutEnvImpl(string, true); }
textexit static void putenv_fini(void) {
for (char **envp = environ; *envp; ++envp) free_s(envp);
free_s(&environ);
}
textstartup static void putenv_init(void) { atexit(putenv_fini); }
const void *const putenv_ctor[] initarray = {putenv_init};