lib/sh/shquote.c

   1 /* Copyright (C) 1999 Free Software Foundation, Inc.
   2
   3    This file is part of GNU Bash, the Bourne Again SHell.
   4
   5    Bash is free software; you can redistribute it and/or modify it under
   6    the terms of the GNU General Public License as published by the Free
   7    Software Foundation; either version 2, or (at your option) any later
   8    version.
   9
  10    Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  11    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13    for more details.
  14
  15    You should have received a copy of the GNU General Public License along
  16    with Bash; see the file COPYING.  If not, write to the Free Software
  17    Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  18
  19 #include <config.h>
  20
  21 #if defined (HAVE_UNISTD_H)
  22 #  ifdef _MINIX
  23 #    include <sys/types.h>
  24 #  endif
  25 #  include <unistd.h>
  26 #endif
  27
  28 #include <stdio.h>
  29
  30 #if !defined(slashify_in_quotes)
  31 #  define slashify_in_quotes "\\`$\"\n"
  32 #endif
  33
  34 extern char *xmalloc ();
  35
  36 /* **************************************************************** */
  37 /*                                                                  */
  38 /*       Functions for quoting strings to be re-read as input       */
  39 /*                                                                  */
  40 /* **************************************************************** */
  41
  42 /* Return a new string which is the single-quoted version of STRING.
  43    Used by alias and trap, among others. */
  44 char *
  45 single_quote (string)
  46      char *string;
  47 {
  48   register int c;
  49   char *result, *r, *s;
  50
  51   result = xmalloc (3 + (4 * strlen (string)));
  52   r = result;
  53   *r++ = '\'';
  54
  55   for (s = string; s && (c = *s); s++)
  56     {
  57       *r++ = c;
  58
  59       if (c == '\'')
  60         {
  61           *r++ = '\\';  /* insert escaped single quote */
  62           *r++ = '\'';
  63           *r++ = '\'';  /* start new quoted string */
  64         }
  65     }
  66
  67   *r++ = '\'';
  68   *r = '\0';
  69
  70   return (result);
  71 }
  72
  73 /* Quote STRING using double quotes.  Return a new string. */
  74 char *
  75 double_quote (string)
  76      char *string;
  77 {
  78   register int c;
  79   char *result, *r, *s;
  80
  81   result = xmalloc (3 + (2 * strlen (string)));
  82   r = result;
  83   *r++ = '"';
  84
  85   for (s = string; s && (c = *s); s++)
  86     {
  87       switch (c)
  88         {
  89         case '"':
  90         case '$':
  91         case '`':
  92         case '\\':
  93         case '\n':              /* XXX */
  94           *r++ = '\\';
  95         default:
  96           *r++ = c;
  97           break;
  98         }
  99     }
 100
 101   *r++ = '"';
 102   *r = '\0';
 103
 104   return (result);
 105 }
 106
 107 /* Remove backslashes that are quoting characters that are special between
 108    double quotes.  Return a new string. */
 109 char *
 110 un_double_quote (string)
 111      char *string;
 112 {
 113   register int c, pass_next;
 114   char *result, *r, *s;
 115
 116   r = result = xmalloc (strlen (string) + 1);
 117
 118   for (pass_next = 0, s = string; s && (c = *s); s++)
 119     {
 120       if (pass_next)
 121         {
 122           *r++ = c;
 123           pass_next = 0;
 124           continue;
 125         }
 126       if (c == '\\' && strchr (slashify_in_quotes, s[1]))
 127         {
 128           pass_next = 1;
 129           continue;
 130         }
 131       *r++ = c;
 132     }
 133
 134   *r = '\0';
 135   return result;
 136 }
 137
 138 /* Quote special characters in STRING using backslashes.  Return a new
 139    string. */
 140 char *
 141 backslash_quote (string)
 142      char *string;
 143 {
 144   int c;
 145   char *result, *r, *s;
 146
 147   result = xmalloc (2 * strlen (string) + 1);
 148
 149   for (r = result, s = string; s && (c = *s); s++)
 150     {
 151       switch (c)
 152         {
 153         case ' ': case '\t': case '\n':         /* IFS white space */
 154         case '\'': case '"': case '\\':         /* quoting chars */
 155         case '|': case '&': case ';':           /* shell metacharacters */
 156         case '(': case ')': case '<': case '>':
 157         case '!': case '{': case '}':           /* reserved words */
 158         case '*': case '[': case '?': case ']': /* globbing chars */
 159         case '^':
 160         case '$': case '`':                     /* expansion chars */
 161           *r++ = '\\';
 162           *r++ = c;
 163           break;
 164 #if 0
 165         case '~':                               /* tilde expansion */
 166           if (s == string || s[-1] == '=' || s[-1] == ':')
 167             *r++ = '\\';
 168           *r++ = c;
 169           break;
 170 #endif
 171         case '#':                               /* comment char */
 172           if (s == string)
 173             *r++ = '\\';
 174           /* FALLTHROUGH */
 175         default:
 176           *r++ = c;
 177           break;
 178         }
 179     }
 180
 181   *r = '\0';
 182   return (result);
 183 }
 184
 185 int
 186 contains_shell_metas (string)
 187      char *string;
 188 {
 189   char *s;
 190
 191   for (s = string; s && *s; s++)
 192     {
 193       switch (*s)
 194         {
 195         case ' ': case '\t': case '\n':         /* IFS white space */
 196         case '\'': case '"': case '\\':         /* quoting chars */
 197         case '|': case '&': case ';':           /* shell metacharacters */
 198         case '(': case ')': case '<': case '>':
 199         case '!': case '{': case '}':           /* reserved words */
 200         case '*': case '[': case '?': case ']': /* globbing chars */
 201         case '^':
 202         case '$': case '`':                     /* expansion chars */
 203           return (1);
 204         case '~':                               /* tilde expansion */
 205           if (s == string || s[-1] == '=' || s[-1] == ':')
 206             return (1);
 207         case '#':
 208           if (s == string)                      /* comment char */
 209             return (1);
 210           /* FALLTHROUGH */
 211         default:
 212           break;
 213         }
 214     }
 215
 216   return (0);
 217 }