contrib/diffutils-2.8/lib/quotesys.c

   1 /* Shell command argument quoting.
   2    Copyright (C) 1994, 1995, 1997 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; see the file COPYING.
  16    If not, write to the Free Software Foundation,
  17    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 /* Written by Paul Eggert <eggert@twinsun.com> */
  20
  21 #if HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <sys/types.h>
  26 #include <quotesys.h>
  27
  28 /* Place into QUOTED a quoted version of ARG suitable for `system'.
  29    Return the length of the resulting string (which is not null-terminated).
  30    If QUOTED is null, return the length without any side effects.  */
  31
  32 size_t
  33 quote_system_arg (quoted, arg)
  34      char *quoted;
  35      char const *arg;
  36 {
  37   char const *a;
  38   size_t len = 0;
  39
  40   /* Scan ARG, copying it to QUOTED if QUOTED is not null,
  41      looking for shell metacharacters.  */
  42
  43   for (a = arg; ; a++)
  44     {
  45       char c = *a;
  46       switch (c)
  47         {
  48         case 0:
  49           /* ARG has no shell metacharacters.  */
  50           return len;
  51
  52         case '=':
  53           if (*arg == '-')
  54             break;
  55           /* Fall through.  */
  56         case '\t': case '\n': case ' ':
  57         case '!': case '"': case '#': case '$': case '%': case '&': case '\'':
  58         case '(': case ')': case '*': case ';':
  59         case '<': case '>': case '?': case '[': case '\\':
  60         case '^': case '`': case '|': case '~':
  61           {
  62             /* ARG has a shell metacharacter.
  63                Start over, quoting it this time.  */
  64
  65             len = 0;
  66             c = *arg++;
  67
  68             /* If ARG is an option, quote just its argument.
  69                This is not necessary, but it looks nicer.  */
  70             if (c == '-'  &&  arg < a)
  71               {
  72                 c = *arg++;
  73
  74                 if (quoted)
  75                   {
  76                     quoted[len] = '-';
  77                     quoted[len + 1] = c;
  78                   }
  79                 len += 2;
  80
  81                 if (c == '-')
  82                   while (arg < a)
  83                     {
  84                       c = *arg++;
  85                       if (quoted)
  86                         quoted[len] = c;
  87                       len++;
  88                       if (c == '=')
  89                         break;
  90                     }
  91                 c = *arg++;
  92               }
  93
  94             if (quoted)
  95               quoted[len] = '\'';
  96             len++;
  97
  98             for (;  c;  c = *arg++)
  99               {
 100                 if (c == '\'')
 101                   {
 102                     if (quoted)
 103                       {
 104                         quoted[len] = '\'';
 105                         quoted[len + 1] = '\\';
 106                         quoted[len + 2] = '\'';
 107                       }
 108                     len += 3;
 109                   }
 110                 if (quoted)
 111                   quoted[len] = c;
 112                 len++;
 113               }
 114
 115             if (quoted)
 116               quoted[len] = '\'';
 117             return len + 1;
 118           }
 119         }
 120
 121       if (quoted)
 122         quoted[len] = c;
 123       len++;
 124     }
 125 }