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/* Copyright (C) 1992,95,96,97,98,99,2000,2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <http://www.gnu.org/licenses/>.
modified for uClibc by Erik Andersen <andersen@codepoet.org>
*/
#include <features.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <bits/uClibc_mutex.h>
__UCLIBC_MUTEX_STATIC(mylock, PTHREAD_MUTEX_INITIALIZER);
/* If this variable is not a null pointer we allocated the current
environment. */
static char **last_environ;
/* This function is used by `setenv' and `putenv'. The difference between
the two functions is that for the former must create a new string which
is then placed in the environment, while the argument of `putenv'
must be used directly. This is all complicated by the fact that we try
to reuse values once generated for a `setenv' call since we can never
free the strings. [in uclibc, we do not] */
static int __add_to_environ(const char *name, const char *value,
int replace)
{
register char **ep;
register size_t size;
char *var_val;
char **new_environ;
/* name may come from putenv() and thus may contain "=VAL" part */
const size_t namelen = strchrnul(name, '=') - name;
int rv = -1;
__UCLIBC_MUTEX_LOCK(mylock);
/* We have to get the pointer now that we have the lock and not earlier
since another thread might have created a new environment. */
ep = __environ;
size = 0;
if (ep != NULL) {
while (*ep != NULL) {
if (!strncmp(*ep, name, namelen) && (*ep)[namelen] == '=') {
/* Found */
if (!replace)
goto DONE_OK;
goto REPLACE;
}
++size;
++ep;
}
}
/* Not found, add at the end */
/* We allocated this space; we can extend it. */
new_environ = realloc(last_environ, (size + 2) * sizeof(char *));
if (new_environ == NULL) {
/* __set_errno(ENOMEM); */
goto DONE;
}
if (__environ != last_environ) {
memcpy(new_environ, __environ, size * sizeof(char *));
}
last_environ = __environ = new_environ;
ep = &new_environ[size];
/* Ensure env is NULL terminated in case malloc below fails */
ep[0] = NULL;
ep[1] = NULL;
REPLACE:
var_val = (char*) name;
/* Build VAR=VAL if we called by setenv, not putenv. */
if (value != NULL) {
const size_t vallen = strlen(value) + 1;
var_val = malloc(namelen + 1 + vallen);
if (var_val == NULL) {
/* __set_errno(ENOMEM); */
goto DONE;
}
memcpy(var_val, name, namelen);
var_val[namelen] = '=';
memcpy(&var_val[namelen + 1], value, vallen);
}
*ep = var_val;
DONE_OK:
rv = 0;
DONE:
__UCLIBC_MUTEX_UNLOCK(mylock);
return rv;
}
int setenv(const char *name, const char *value, int replace)
{
if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) {
__set_errno(EINVAL);
return -1;
}
/* NB: setenv("VAR", NULL, 1) inserts "VAR=" string */
return __add_to_environ(name, value ? value : "", replace);
}
libc_hidden_def(setenv)
int unsetenv(const char *name)
{
const char *eq;
size_t len;
char **ep;
if (name == NULL || *name == '\0'
|| *(eq = strchrnul(name, '=')) == '='
) {
__set_errno(EINVAL);
return -1;
}
len = eq - name; /* avoiding strlen this way */
__UCLIBC_MUTEX_LOCK(mylock);
ep = __environ;
/* NB: clearenv(); unsetenv("foo"); should not segfault */
if (ep) while (*ep != NULL) {
if (!strncmp(*ep, name, len) && (*ep)[len] == '=') {
/* Found it. Remove this pointer by moving later ones back. */
char **dp = ep;
do {
dp[0] = dp[1];
} while (*dp++);
/* Continue the loop in case NAME appears again. */
} else {
++ep;
}
}
__UCLIBC_MUTEX_UNLOCK(mylock);
return 0;
}
libc_hidden_def(unsetenv)
/* The `clearenv' was planned to be added to POSIX.1 but probably
never made it. Nevertheless the POSIX.9 standard (POSIX bindings
for Fortran 77) requires this function. */
int clearenv(void)
{
__UCLIBC_MUTEX_LOCK(mylock);
/* If we allocated this environment we can free it.
* If we did not allocate this environment, it's NULL already
* and is safe to free(). */
free(last_environ);
last_environ = NULL;
/* Clearing environ removes the whole environment. */
__environ = NULL;
__UCLIBC_MUTEX_UNLOCK(mylock);
return 0;
}
/* Put STRING, which is of the form "NAME=VALUE", in the environment. */
int putenv(char *string)
{
if (strchr(string, '=') != NULL) {
return __add_to_environ(string, NULL, 1);
}
return unsetenv(string);
}
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