src/libs/libgroff/putenv.c

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