lib/sh/shquote.c

/* shquote - functions to quote and dequote strings */

/* Copyright (C) 1999 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Bash is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <config.h>

#if defined (HAVE_UNISTD_H)
#  ifdef _MINIX
#    include <sys/types.h>
#  endif
#  include <unistd.h>
#endif

#include <stdio.h>

#include "syntax.h"
#include <xmalloc.h>

/* **************************************************************** */
/*								    */
/*	 Functions for quoting strings to be re-read as input	    */
/*								    */
/* **************************************************************** */

/* Return a new string which is the single-quoted version of STRING.
   Used by alias and trap, among others. */
char *
sh_single_quote (string)
     char *string;
{
  register int c;
  char *result, *r, *s;

  result = (char *)xmalloc (3 + (4 * strlen (string)));
  r = result;
  *r++ = '\'';

  for (s = string; s && (c = *s); s++)
    {
      *r++ = c;

      if (c == '\'')
	{
	  *r++ = '\\';	/* insert escaped single quote */
	  *r++ = '\'';
	  *r++ = '\'';	/* start new quoted string */
	}
    }

  *r++ = '\'';
  *r = '\0';

  return (result);
}

/* Quote STRING using double quotes.  Return a new string. */
char *
sh_double_quote (string)
     char *string;
{
  register unsigned char c;
  char *result, *r, *s;

  result = (char *)xmalloc (3 + (2 * strlen (string)));
  r = result;
  *r++ = '"';

  for (s = string; s && (c = *s); s++)
    {
      /* Backslash-newline disappears within double quotes, so don't add one. */
      if ((sh_syntaxtab[c] & CBSDQUOTE) && c != '\n')
	*r++ = '\\';
      else if (c == CTLESC || c == CTLNUL)
	*r++ = CTLESC;		/* could be '\\'? */

      *r++ = c;
    }

  *r++ = '"';
  *r = '\0';

  return (result);
}

/* Turn S into a simple double-quoted string.  If FLAGS is non-zero, quote
   double quote characters in S with backslashes. */
char *
sh_mkdoublequoted (s, slen, flags)
     const char *s;
     int slen, flags;
{
  char *r, *ret;
  int rlen;

  rlen = (flags == 0) ? slen + 3 : (2 * slen) + 1;
  ret = r = (char *)xmalloc (rlen);
  
  *r++ = '"';
  while (*s)
    {
      if (flags && *s == '"')
	*r++ = '\\';
      *r++ = *s++;
    }
  *r++ = '"';
  *r = '\0';

  return ret;
}

/* Remove backslashes that are quoting characters that are special between
   double quotes.  Return a new string.  XXX - should this handle CTLESC
   and CTLNUL? */
char *
sh_un_double_quote (string)
     char *string;
{
  register int c, pass_next;
  char *result, *r, *s;

  r = result = (char *)xmalloc (strlen (string) + 1);

  for (pass_next = 0, s = string; s && (c = *s); s++)
    {
      if (pass_next)
	{
	  *r++ = c;
	  pass_next = 0;
	  continue;
	}
      if (c == '\\' && (sh_syntaxtab[(unsigned char) s[1]] & CBSDQUOTE))
	{
	  pass_next = 1;
	  continue;
	}
      *r++ = c;
    }

  *r = '\0';
  return result;
}

/* Quote special characters in STRING using backslashes.  Return a new
   string.  NOTE:  if the string is to be further expanded, we need a
   way to protect the CTLESC and CTLNUL characters.  As I write this,
   the current callers will never cause the string to be expanded without
   going through the shell parser, which will protect the internal
   quoting characters. */
char *
sh_backslash_quote (string)
     char *string;
{
  int c;
  char *result, *r, *s;

  result = (char *)xmalloc (2 * strlen (string) + 1);

  for (r = result, s = string; s && (c = *s); s++)
    {
      switch (c)
	{
	case ' ': case '\t': case '\n':		/* IFS white space */
	case '\'': case '"': case '\\':		/* quoting chars */
	case '|': case '&': case ';':		/* shell metacharacters */
	case '(': case ')': case '<': case '>':
	case '!': case '{': case '}':		/* reserved words */
	case '*': case '[': case '?': case ']':	/* globbing chars */
	case '^':
	case '$': case '`':			/* expansion chars */
	case ',':				/* brace expansion */
	  *r++ = '\\';
	  *r++ = c;
	  break;
#if 0
	case '~':				/* tilde expansion */
	  if (s == string || s[-1] == '=' || s[-1] == ':')
	    *r++ = '\\';
	  *r++ = c;
	  break;

	case CTLESC: case CTLNUL:		/* internal quoting characters */
	  *r++ = CTLESC;			/* could be '\\'? */
	  *r++ = c;
	  break;
#endif

	case '#':				/* comment char */
	  if (s == string)
	    *r++ = '\\';
	  /* FALLTHROUGH */
	default:
	  *r++ = c;
	  break;
	}
    }

  *r = '\0';
  return (result);
}

#if defined (PROMPT_STRING_DECODE)
/* Quote characters that get special treatment when in double quotes in STRING
   using backslashes.  Return a new string. */
char *
sh_backslash_quote_for_double_quotes (string)
     char *string;
{
  unsigned char c;
  char *result, *r, *s;

  result = (char *)xmalloc (2 * strlen (string) + 1);

  for (r = result, s = string; s && (c = *s); s++)
    {
      if (sh_syntaxtab[c] & CBSDQUOTE)
	*r++ = '\\';
      /* I should probably add flags for these to sh_syntaxtab[] */
      else if (c == CTLESC || c == CTLNUL)
	*r++ = CTLESC;		/* could be '\\'? */

      *r++ = c;
    }

  *r = '\0';
  return (result);
}
#endif /* PROMPT_STRING_DECODE */

int
sh_contains_shell_metas (string)
     char *string;
{
  char *s;

  for (s = string; s && *s; s++)
    {
      switch (*s)
	{
	case ' ': case '\t': case '\n':		/* IFS white space */
	case '\'': case '"': case '\\':		/* quoting chars */
	case '|': case '&': case ';':		/* shell metacharacters */
	case '(': case ')': case '<': case '>':
	case '!': case '{': case '}':		/* reserved words */
	case '*': case '[': case '?': case ']':	/* globbing chars */
	case '^':
	case '$': case '`':			/* expansion chars */
	  return (1);
	case '~':				/* tilde expansion */
	  if (s == string || s[-1] == '=' || s[-1] == ':')
	    return (1);
	  break;
	case '#':
	  if (s == string)			/* comment char */
	    return (1);
	  /* FALLTHROUGH */
	default:
	  break;
	}
    }

  return (0);
}