lib/libc/stdlib/getenv.c

   1 /*      $NetBSD: getenv.c,v 1.35 2010/11/14 22:04:36 tron Exp $ */
   2
   3 /*
   4  * Copyright (c) 1987, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)getenv.c    8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: getenv.c,v 1.35 2010/11/14 22:04:36 tron Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <assert.h>
  43 #include <errno.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 #include "env.h"
  48 #include "reentrant.h"
  49 #include "local.h"
  50
  51 __weak_alias(getenv_r, _getenv_r)
  52
  53 /*
  54  * getenv --
  55  *      Returns ptr to value associated with name, if any, else NULL.
  56  *      XXX: we cannot use getenv_r to implement this, because getenv()
  57  *      cannot use a shared buffer, because if it did, subsequent calls
  58  *      to getenv would trash previous results.
  59  */
  60 char *
  61 getenv(const char *name)
  62 {
  63         size_t l_name;
  64         char *result;
  65
  66         _DIAGASSERT(name != NULL);
  67
  68         l_name = __envvarnamelen(name, false);
  69         if (l_name == 0)
  70                 return NULL;
  71
  72         result = NULL;
  73         if (__readlockenv()) {
  74                 result = __findenvvar(name, l_name);
  75                 (void)__unlockenv();
  76         }
  77
  78         return result;
  79 }
  80
  81 int
  82 getenv_r(const char *name, char *buf, size_t len)
  83 {
  84         size_t l_name;
  85         int rv;
  86
  87         _DIAGASSERT(name != NULL);
  88
  89         l_name = __envvarnamelen(name, false);
  90         if (l_name == 0) {
  91                 errno = ENOENT;
  92                 return -1;
  93         }
  94
  95         rv = -1;
  96         if (__readlockenv()) {
  97                 const char *value;
  98
  99                 value = __findenvvar(name, l_name);
 100                 if (value != NULL) {
 101                         if (strlcpy(buf, value, len) < len) {
 102                                 rv = 0;
 103                         } else {
 104                                 errno = ERANGE;
 105                         }
 106                 } else {
 107                         errno = ENOENT;
 108                 }
 109                 (void)__unlockenv();
 110         }
 111
 112         return rv;
 113 }