130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/* $NetBSD: getenv.c,v 1.18 2005/09/25 20:08:01 christos Exp $ */
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/*
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* Copyright (c) 1987, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)getenv.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: getenv.c,v 1.18 2005/09/25 20:08:01 christos Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include "local.h"
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#include "reentrant.h"
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#ifdef _REENTRANT
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rwlock_t __environ_lock = RWLOCK_INITIALIZER;
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#endif
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extern char **environ;
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__weak_alias(getenv_r, _getenv_r)
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/*
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* getenv --
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* Returns ptr to value associated with name, if any, else NULL.
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* XXX: we cannot use getenv_r to implement this, because getenv()
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* cannot use a shared buffer, because if it did, subsequent calls
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* to getenv would trash previous results.
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*/
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char *
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getenv(const char *name)
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{
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int offset;
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char *result;
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_DIAGASSERT(name != NULL);
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rwlock_rdlock(&__environ_lock);
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result = __findenv(name, &offset);
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rwlock_unlock(&__environ_lock);
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return result;
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}
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int
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getenv_r(const char *name, char *buf, size_t len)
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{
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int offset;
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char *result;
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int rv = -1;
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_DIAGASSERT(name != NULL);
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rwlock_rdlock(&__environ_lock);
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result = __findenv(name, &offset);
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if (result == NULL) {
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errno = ENOENT;
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goto out;
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}
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if (strlcpy(buf, result, len) >= len) {
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errno = ERANGE;
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goto out;
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}
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rv = 0;
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out:
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rwlock_unlock(&__environ_lock);
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return rv;
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}
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/*
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* __findenv --
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* Returns pointer to value associated with name, if any, else NULL.
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* Sets offset to be the offset of the name/value combination in the
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* environmental array, for use by setenv(3) and unsetenv(3).
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* Explicitly removes '=' in argument name.
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*
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* This routine *should* be a static; don't use it.
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*/
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char *
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__findenv(const char *name, int *offset)
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{
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size_t len;
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const char *np;
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char **p, *c;
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if (name == NULL || environ == NULL)
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return NULL;
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for (np = name; *np && *np != '='; ++np)
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continue;
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len = np - name;
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for (p = environ; (c = *p) != NULL; ++p)
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if (strncmp(c, name, len) == 0 && c[len] == '=') {
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*offset = p - environ;
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return c + len + 1;
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}
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return NULL;
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}
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