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/* Copyright (C) 1992, 1995 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#if defined(_REENTRENT) || defined(_THREAD_SAFE)
# include <pthread.h>
/* We need to initialize the mutex. For this we use a method provided
by pthread function 'pthread_once'. For this we need a once block. */
static pthread_once__t _once_block = pthread_once_init;
/* This is the mutex which protects the global environment of simultaneous
modifications. */
static pthread_mutex_t _setenv_mutex;
static void
DEFUN_VOID(_init_setenv_mutex)
{
pthread_mutex_init(&_setenv_mutex, pthread_mutexattr_default);
}
# define LOCK() \
do { pthread_once(&_once_block, _init_setenv_mutex);
pthread_mutex_lock(&_setenv_mutex); } while (0)
# define UNLOCK() pthread_mutex_unlock(&_setenv_mutex)
#else /* !_REENTRENT && !_THREAD_SAFE */
# define LOCK()
# define UNLOCK()
#endif /* _REENTRENT || _THREAD_SAFE */
int setenv(const char *name, const char *value, int replace)
{
register char **ep;
register size_t size;
const size_t namelen = strlen (name);
const size_t vallen = strlen (value);
int result = 0;
LOCK();
size = 0;
for (ep = __environ; *ep != NULL; ++ep)
if (!memcmp (*ep, name, namelen) && (*ep)[namelen] == '=')
break;
else
++size;
if (*ep == NULL)
{
static char **last_environ = NULL;
char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
if (new_environ == NULL)
{
result = -1;
goto do_return;
}
(void) memcpy((__ptr_t) new_environ, (__ptr_t) __environ, size * sizeof(char *));
new_environ[size] = malloc (namelen + 1 + vallen + 1);
if (new_environ[size] == NULL)
{
free (new_environ);
errno = ENOMEM;
result = -1;
goto do_return;
}
memcpy (new_environ[size], name, namelen);
new_environ[size][namelen] = '=';
memcpy (&new_environ[size][namelen + 1], value, vallen + 1);
new_environ[size + 1] = NULL;
if (last_environ != NULL)
free ((__ptr_t) last_environ);
last_environ = new_environ;
__environ = new_environ;
}
else if (replace)
{
size_t len = strlen (*ep);
if (len < namelen + 1 + vallen)
{
char *new = malloc (namelen + 1 + vallen + 1);
if (new == NULL)
{
result = -1;
goto do_return;
}
*ep = new;
memcpy (*ep, name, namelen);
(*ep)[namelen] = '=';
}
memcpy (&(*ep)[namelen + 1], value, vallen + 1);
}
do_return:
UNLOCK();
return result;
}
void unsetenv(const char *name)
{
register char **ep;
register char **dp;
const size_t namelen = strlen (name);
LOCK();
for (dp = ep = __environ; *ep != NULL; ++ep)
if (memcmp (*ep, name, namelen) || (*ep)[namelen] != '=')
{
*dp = *ep;
++dp;
}
*dp = NULL;
UNLOCK();
}
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