driver/substit.c

   1 /*
   2  * Copyright (c) 2002 Stephen Williams (steve@icarus.com)
   3  *
   4  *    This source code is free software; you can redistribute it
   5  *    and/or modify it in source code form under the terms of the GNU
   6  *    General Public License as published by the Free Software
   7  *    Foundation; either version 2 of the License, or (at your option)
   8  *    any later version.
   9  *
  10  *    This program is distributed in the hope that it will be useful,
  11  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *    GNU General Public License for more details.
  14  *
  15  *    You should have received a copy of the GNU General Public License
  16  *    along with this program; if not, write to the Free Software
  17  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  18  */
  19 #ifdef HAVE_CVS_IDENT
  20 #ident "$Id: substit.c,v 1.5 2003/12/19 01:27:10 steve Exp $"
  21 #endif
  22
  23 # include  <string.h>
  24 # include  <stdlib.h>
  25 #ifdef HAVE_MALLOC_H
  26 # include  <malloc.h>
  27 #endif
  28
  29
  30 char* substitutions(const char*str)
  31 {
  32       size_t nbuf = strlen(str) + 1;
  33       char*buf = malloc(nbuf);
  34       char*cp = buf;
  35
  36       while (*str) {
  37
  38             if ((str[0] == '$') && (str[1] == '(')) {
  39                     /* If I find a $(x) string in the source, replace
  40                        it in the destination with the contents of the
  41                        environment variable x. */
  42                   char*name;
  43                   char*value;
  44                   const char*ep = strchr(str, ')');
  45                   str += 2;
  46
  47                   name = malloc(ep-str+1);
  48                   strncpy(name, str, ep-str);
  49                   name[ep-str] = 0;
  50
  51                   str = ep + 1;
  52
  53                   value = getenv(name);
  54                   free(name);
  55                   if (value == 0)
  56                         continue;
  57
  58                   if (strlen(value) >= (nbuf - (cp-buf))) {
  59                         size_t old_size = cp - buf;
  60                         nbuf = (cp - buf) + strlen(value) + 1;
  61                         buf = realloc(buf, nbuf);
  62                         cp = buf + old_size;
  63                   }
  64
  65                   strcpy(cp, value);
  66                   cp += strlen(cp);
  67
  68             } else {
  69                   if ( cp == (buf + nbuf) ) {
  70                         size_t old_size = nbuf;
  71                         nbuf = old_size + 32;
  72                         buf = realloc(buf, nbuf);
  73                         cp = buf + old_size;
  74                   }
  75
  76                   *cp++ = *str++;
  77             }
  78       }
  79
  80         /* Add the trailing nul to the string, and reallocate the
  81            buffer to be a tight fit. */
  82       if ( cp == (buf + nbuf) ) {
  83             size_t old_size = nbuf;
  84             nbuf = old_size + 1;
  85             buf = realloc(buf, nbuf);
  86             buf[old_size] = 0;
  87       } else {
  88             *cp++ = 0;
  89             nbuf = cp - buf;
  90             buf = realloc(buf, nbuf);
  91       }
  92
  93       return buf;
  94 }
  95
  96
  97 /*
  98  * $Log: substit.c,v $
  99  * Revision 1.5  2003/12/19 01:27:10  steve
 100  *  Fix various unsigned compare warnings.
 101  *
 102  * Revision 1.4  2002/08/12 01:35:01  steve
 103  *  conditional ident string using autoconfig.
 104  *
 105  * Revision 1.3  2002/08/11 23:47:04  steve
 106  *  Add missing Log and Ident strings.
 107  *
 108  * Revision 1.2  2002/06/25 01:33:01  steve
 109  *  include malloc.h only when available.
 110  *
 111  * Revision 1.1  2002/06/23 20:10:51  steve
 112  *  Variable substitution in command files.
 113  *
 114  */
 115