lib/roken/putenv.c

   1 /*
   2  * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #include <stdlib.h>
  37
  38 #if !HAVE_DECL_ENVIRON
  39 extern char **environ;
  40 #endif
  41
  42 /*
  43  * putenv --
  44  *      String points to a string of the form name=value.
  45  *
  46  *      Makes the value of the environment variable name equal to
  47  *      value by altering an existing variable or creating a new one.
  48  */
  49
  50 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
  51 putenv(const char *string)
  52 {
  53     int i;
  54     const char *eq = (const char *)strchr(string, '=');
  55     int len;
  56
  57     if (eq == NULL)
  58         return 1;
  59     len = eq - string;
  60
  61     if(environ == NULL) {
  62         environ = malloc(sizeof(char*));
  63         if(environ == NULL)
  64             return 1;
  65         environ[0] = NULL;
  66     }
  67
  68     for(i = 0; environ[i] != NULL; i++)
  69         if(strncmp(string, environ[i], len) == 0) {
  70             environ[i] = string;
  71             return 0;
  72         }
  73     environ = realloc(environ, sizeof(char*) * (i + 2));
  74     if(environ == NULL)
  75         return 1;
  76     environ[i]   = string;
  77     environ[i+1] = NULL;
  78     return 0;
  79 }