stdlib/setenv.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1987, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <stddef.h>
  60 #include <stdlib.h>
  61 #include <string.h>
  62
  63 #include <crt_externs.h>
  64
  65 char *__findenv __P((const char *, int *));
  66
  67 /*
  68  * setenv --
  69  *      Set the value of the environmental variable "name" to be
  70  *      "value".  If rewrite is set, replace any current value.
  71  */
  72 int
  73 setenv(name, value, rewrite)
  74         register const char *name;
  75         register const char *value;
  76         int rewrite;
  77 {
  78         static int alloced;                     /* if allocated space before */
  79         register char *c;
  80         int l_value, offset;
  81         char ***environp = _NSGetEnviron();
  82
  83         if (*value == '=')                      /* no `=' in value */
  84                 ++value;
  85         l_value = strlen(value);
  86         if ((c = __findenv(name, &offset))) {   /* find if already exists */
  87                 if (!rewrite)
  88                         return (0);
  89                 if (strlen(c) >= l_value) {     /* old larger; copy over */
  90                         while (*c++ = *value++);
  91                         return (0);
  92                 }
  93         } else {                                        /* create new slot */
  94                 register int cnt;
  95                 register char **p;
  96
  97                 for (p = *environp, cnt = 0; *p; ++p, ++cnt);
  98                 if (alloced) {                  /* just increase size */
  99                         *environp = (char **)realloc((char *)*environp,
 100                             (size_t)(sizeof(char *) * (cnt + 2)));
 101                         if (!*environp)
 102                                 return (-1);
 103                 }
 104                 else {                          /* get new space */
 105                         alloced = 1;            /* copy old entries into it */
 106                         p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
 107                         if (!p)
 108                                 return (-1);
 109                         bcopy(*environp, p, cnt * sizeof(char *));
 110                         *environp = p;
 111                 }
 112                 (*environp)[cnt + 1] = NULL;
 113                 offset = cnt;
 114         }
 115         for (c = (char *)name; *c && *c != '='; ++c);   /* no `=' in name */
 116         if (!((*environp)[offset] =                     /* name + `=' + value */
 117             malloc((size_t)((int)(c - name) + l_value + 2))))
 118                 return (-1);
 119         for (c = (*environp)[offset]; (*c = *name++) && *c != '='; ++c);
 120         for (*c++ = '='; *c++ = *value++;);
 121         return (0);
 122 }
 123
 124 /*
 125  * unsetenv(name) --
 126  *      Delete environmental variable "name".
 127  */
 128 void
 129 unsetenv(name)
 130         const char *name;
 131 {
 132         char **environ = *_NSGetEnviron();
 133         register char **p;
 134         int offset;
 135
 136         while (__findenv(name, &offset))        /* if set multiple times */
 137                 for (p = &environ[offset];; ++p)
 138                         if (!(*p = *(p + 1)))
 139                                 break;
 140 }