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135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
/* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2013 Free Software
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Foundation, Inc.
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NOTE: The canonical source of this file is maintained with the GNU C
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Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
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This program is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3 of the License, or any
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later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <config.h>
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/* Specification. */
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#include <stdlib.h>
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#include <stddef.h>
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/* Include errno.h *after* sys/types.h to work around header problems
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on AIX 3.2.5. */
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#include <errno.h>
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#ifndef __set_errno
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# define __set_errno(ev) ((errno) = (ev))
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#endif
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#include <string.h>
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#include <unistd.h>
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#if _LIBC
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# if HAVE_GNU_LD
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# define environ __environ
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# else
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extern char **environ;
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# endif
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#endif
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#if _LIBC
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/* This lock protects against simultaneous modifications of 'environ'. */
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# include <bits/libc-lock.h>
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__libc_lock_define_initialized (static, envlock)
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# define LOCK __libc_lock_lock (envlock)
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# define UNLOCK __libc_lock_unlock (envlock)
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#else
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# define LOCK
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# define UNLOCK
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#endif
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static int
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_unsetenv (const char *name)
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{
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size_t len;
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char **ep;
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if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
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{
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__set_errno (EINVAL);
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return -1;
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}
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len = strlen (name);
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LOCK;
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ep = environ;
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while (*ep != NULL)
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if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
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{
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/* Found it. Remove this pointer by moving later ones back. */
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char **dp = ep;
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do
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dp[0] = dp[1];
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while (*dp++);
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/* Continue the loop in case NAME appears again. */
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}
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else
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++ep;
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UNLOCK;
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return 0;
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}
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/* Put STRING, which is of the form "NAME=VALUE", in the environment.
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If STRING contains no '=', then remove STRING from the environment. */
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int
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putenv (char *string)
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{
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const char *const name_end = strchr (string, '=');
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register size_t size;
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register char **ep;
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if (name_end == NULL)
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{
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/* Remove the variable from the environment. */
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return _unsetenv (string);
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}
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size = 0;
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for (ep = environ; *ep != NULL; ++ep)
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if (!strncmp (*ep, string, name_end - string) &&
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(*ep)[name_end - string] == '=')
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break;
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else
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++size;
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if (*ep == NULL)
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{
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static char **last_environ = NULL;
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char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
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if (new_environ == NULL)
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return -1;
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(void) memcpy ((void *) new_environ, (void *) environ,
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size * sizeof (char *));
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new_environ[size] = (char *) string;
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new_environ[size + 1] = NULL;
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free (last_environ);
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last_environ = new_environ;
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environ = new_environ;
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}
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else
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*ep = string;
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return 0;
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}
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