gnu/dist/groff/src/libs/libgroff/putenv.c

   1 /*      $NetBSD$        */
   2
   3 /* Copyright (C) 1991, 2001 Free Software Foundation, Inc.
   4 This file is part of the GNU C Library.
   5
   6 The GNU C Library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public License as
   8 published by the Free Software Foundation; either version 2 of the
   9 License, or (at your option) any later version.
  10
  11 The GNU C Library is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with the GNU C Library; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  19 Cambridge, MA 02139, USA.  */
  20
  21 /* Hacked slightly by jjc@jclark.com for groff. */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <string.h>
  28
  29 #ifdef __STDC__
  30 #include <stddef.h>
  31 typedef void *PTR;
  32 typedef size_t SIZE_T;
  33 #else /* not __STDC__ */
  34 typedef char *PTR;
  35 typedef int SIZE_T;
  36 #endif /* not __STDC__ */
  37
  38 #ifdef HAVE_STDLIB_H
  39 #include <stdlib.h>
  40 #else /* not HAVE_STDLIB_H */
  41 PTR malloc();
  42 #endif /* not HAVE_STDLIB_H */
  43
  44 #ifndef NULL
  45 #define NULL 0
  46 #endif
  47
  48 extern char **environ;
  49
  50 /* Put STRING, which is of the form "NAME=VALUE", in the environment.  */
  51
  52 int putenv(const char *string)
  53 {
  54   char *name_end = strchr(string, '=');
  55   SIZE_T size;
  56   char **ep;
  57
  58   if (name_end == NULL)
  59     {
  60       /* Remove the variable from the environment.  */
  61       size = strlen(string);
  62       for (ep = environ; *ep != NULL; ++ep)
  63         if (!strncmp(*ep, string, size) && (*ep)[size] == '=')
  64           {
  65             while (ep[1] != NULL)
  66               {
  67                 ep[0] = ep[1];
  68                 ++ep;
  69               }
  70             *ep = NULL;
  71             return 0;
  72           }
  73     }
  74
  75   size = 0;
  76   for (ep = environ; *ep != NULL; ++ep)
  77     if (!strncmp(*ep, string, name_end - string)
  78         && (*ep)[name_end - string] == '=')
  79       break;
  80     else
  81       ++size;
  82
  83   if (*ep == NULL)
  84     {
  85       static char **last_environ = NULL;
  86       char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
  87       if (new_environ == NULL)
  88         return -1;
  89       (void) memcpy((PTR) new_environ, (PTR) environ, size * sizeof(char *));
  90       new_environ[size] = (char *) string;
  91       new_environ[size + 1] = NULL;
  92       if (last_environ != NULL)
  93         free((PTR) last_environ);
  94       last_environ = new_environ;
  95       environ = new_environ;
  96     }
  97   else
  98     *ep = (char *) string;
  99
 100   return 0;
 101 }