src/libs/libgroff/putenv.c

   1 /* Copyright (C) 1991 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 #include <string.h>
  22
  23 #ifdef __STDC__
  24 #include <stddef.h>
  25 typedef void *PTR;
  26 typedef size_t SIZE_T;
  27 #else /* not __STDC__ */
  28 typedef char *PTR;
  29 typedef int SIZE_T;
  30 #endif /* not __STDC__ */
  31
  32 #ifdef HAVE_STDLIB_H
  33 #include <stdlib.h>
  34 #else /* not HAVE_STDLIB_H */
  35 PTR malloc();
  36 #endif /* not HAVE_STDLIB_H */
  37
  38 #ifndef NULL
  39 #define NULL 0
  40 #endif
  41
  42 extern char **environ;
  43
  44 /* Put STRING, which is of the form "NAME=VALUE", in the environment.  */
  45
  46 int putenv(const char *string)
  47 {
  48   char *name_end = strchr(string, '=');
  49   SIZE_T size;
  50   char **ep;
  51
  52   if (name_end == NULL)
  53     {
  54       /* Remove the variable from the environment.  */
  55       size = strlen(string);
  56       for (ep = environ; *ep != NULL; ++ep)
  57         if (!strncmp(*ep, string, size) && (*ep)[size] == '=')
  58           {
  59             while (ep[1] != NULL)
  60               {
  61                 ep[0] = ep[1];
  62                 ++ep;
  63               }
  64             *ep = NULL;
  65             return 0;
  66           }
  67     }
  68
  69   size = 0;
  70   for (ep = environ; *ep != NULL; ++ep)
  71     if (!strncmp(*ep, string, name_end - string)
  72         && (*ep)[name_end - string] == '=')
  73       break;
  74     else
  75       ++size;
  76
  77   if (*ep == NULL)
  78     {
  79       static char **last_environ = NULL;
  80       char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
  81       if (new_environ == NULL)
  82         return -1;
  83       (void) memcpy((PTR) new_environ, (PTR) environ, size * sizeof(char *));
  84       new_environ[size] = (char *) string;
  85       new_environ[size + 1] = NULL;
  86       if (last_environ != NULL)
  87         free((PTR) last_environ);
  88       last_environ = new_environ;
  89       environ = new_environ;
  90     }
  91   else
  92     *ep = (char *) string;
  93
  94   return 0;
  95 }