gnu/dist/diffutils/lib/quotesys.c

   1 /*      $NetBSD$        */
   2
   3 /* Shell command argument quoting.
   4    Copyright (C) 1994, 1995, 1997 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program 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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; see the file COPYING.
  18    If not, write to the Free Software Foundation,
  19    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /* Written by Paul Eggert <eggert@twinsun.com> */
  22
  23 #if HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 #include <sys/types.h>
  28 #include <quotesys.h>
  29
  30 /* Place into QUOTED a quoted version of ARG suitable for `system'.
  31    Return the length of the resulting string (which is not null-terminated).
  32    If QUOTED is null, return the length without any side effects.  */
  33
  34 size_t
  35 quote_system_arg (quoted, arg)
  36      char *quoted;
  37      char const *arg;
  38 {
  39   char const *a;
  40   size_t len = 0;
  41
  42   /* Scan ARG, copying it to QUOTED if QUOTED is not null,
  43      looking for shell metacharacters.  */
  44
  45   for (a = arg; ; a++)
  46     {
  47       char c = *a;
  48       switch (c)
  49         {
  50         case 0:
  51           /* ARG has no shell metacharacters.  */
  52           return len;
  53
  54         case '=':
  55           if (*arg == '-')
  56             break;
  57           /* Fall through.  */
  58         case '\t': case '\n': case ' ':
  59         case '!': case '"': case '#': case '$': case '%': case '&': case '\'':
  60         case '(': case ')': case '*': case ';':
  61         case '<': case '>': case '?': case '[': case '\\':
  62         case '^': case '`': case '|': case '~':
  63           {
  64             /* ARG has a shell metacharacter.
  65                Start over, quoting it this time.  */
  66
  67             len = 0;
  68             c = *arg++;
  69
  70             /* If ARG is an option, quote just its argument.
  71                This is not necessary, but it looks nicer.  */
  72             if (c == '-'  &&  arg < a)
  73               {
  74                 c = *arg++;
  75
  76                 if (quoted)
  77                   {
  78                     quoted[len] = '-';
  79                     quoted[len + 1] = c;
  80                   }
  81                 len += 2;
  82
  83                 if (c == '-')
  84                   while (arg < a)
  85                     {
  86                       c = *arg++;
  87                       if (quoted)
  88                         quoted[len] = c;
  89                       len++;
  90                       if (c == '=')
  91                         break;
  92                     }
  93                 c = *arg++;
  94               }
  95
  96             if (quoted)
  97               quoted[len] = '\'';
  98             len++;
  99
 100             for (;  c;  c = *arg++)
 101               {
 102                 if (c == '\'')
 103                   {
 104                     if (quoted)
 105                       {
 106                         quoted[len] = '\'';
 107                         quoted[len + 1] = '\\';
 108                         quoted[len + 2] = '\'';
 109                       }
 110                     len += 3;
 111                   }
 112                 if (quoted)
 113                   quoted[len] = c;
 114                 len++;
 115               }
 116
 117             if (quoted)
 118               quoted[len] = '\'';
 119             return len + 1;
 120           }
 121         }
 122
 123       if (quoted)
 124         quoted[len] = c;
 125       len++;
 126     }
 127 }