coreutils/lib/setenv.c

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/* Copyright (C) 1992, 1995, 2000, 2003 Free Software Foundation, Inc.
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NOTE: The canonical source of this file is maintained with the GNU C Library.
Bugs can be reported to bug-glibc@prep.ai.mit.edu.
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; either version 2, or (at your option) any
later version.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA. */
#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
#include <errno.h>
#if !_LIBC
# if !defined errno
extern int errno;
# endif
# define __set_errno(ev) ((errno) = (ev))
#endif
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#if _LIBC || HAVE_STDLIB_H
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# include <stdlib.h>
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#endif
#if _LIBC || HAVE_STRING_H
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# include <string.h>
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#endif
#if _LIBC || HAVE_UNISTD_H
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# include <unistd.h>
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#endif
#ifndef HAVE_GNU_LD
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# define __environ environ
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#endif
#if _LIBC
/* This lock protects against simultaneous modifications of `environ'. */
# include <bits/libc-lock.h>
__libc_lock_define_initialized (static, envlock)
# define LOCK __libc_lock_lock (envlock)
# define UNLOCK __libc_lock_unlock (envlock)
#else
# define LOCK
# define UNLOCK
#endif
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int
setenv (name, value, replace)
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) + 1;
size = 0;
for (ep = __environ; *ep != NULL; ++ep)
if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
break;
else
++size;
if (*ep == NULL)
{
static char **last_environ;
char **new_environ;
if (__environ == last_environ)
/* We allocated this space; we can extend it. */
new_environ = (char **) realloc (last_environ,
(size + 2) * sizeof (char *));
else
new_environ = (char **) malloc ((size + 2) * sizeof (char *));
if (new_environ == NULL)
return -1;
new_environ[size] = malloc (namelen + 1 + vallen);
if (new_environ[size] == NULL)
{
free (new_environ);
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errno = ENOMEM;
return -1;
}
if (__environ != last_environ)
memcpy ((char *) new_environ, (char *) __environ,
size * sizeof (char *));
memcpy (new_environ[size], name, namelen);
new_environ[size][namelen] = '=';
memcpy (&new_environ[size][namelen + 1], value, vallen);
new_environ[size + 1] = NULL;
last_environ = __environ = new_environ;
}
else if (replace)
{
size_t len = strlen (*ep);
if (len + 1 < namelen + 1 + vallen)
{
/* The existing string is too short; malloc a new one. */
char *new = malloc (namelen + 1 + vallen);
if (new == NULL)
return -1;
*ep = new;
}
memcpy (*ep, name, namelen);
(*ep)[namelen] = '=';
memcpy (&(*ep)[namelen + 1], value, vallen);
}
return 0;
}
/* WARNING: This function is not used by setenv-related code.
But it *is* used by putenv.c, so elide the code below.
Instead, use the static copy of the function that's in putenv.c. */
#if 0
int
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unsetenv (name)
const char *name;
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{
size_t len;
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char **ep;
if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
{
__set_errno (EINVAL);
return -1;
}
len = strlen (name);
LOCK;
ep = __environ;
while (*ep != NULL)
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if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
{
/* Found it. Remove this pointer by moving later ones back. */
char **dp = ep;
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do
dp[0] = dp[1];
while (*dp++);
/* Continue the loop in case NAME appears again. */
}
else
++ep;
UNLOCK;
return 0;
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}
#endif