#! /bin/sh -e

if [ $# -eq 3 -a "$2" = '-d' ]; then
    pdir="-d $3"
elif [ $# -ne 1 ]; then
    echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
    exit 1
fi
case "$1" in
    -patch) patch $pdir -f --no-backup-if-mismatch -p0 < $0;;
    -unpatch) patch $pdir -f --no-backup-if-mismatch -R -p0 < $0;;
    *)
	echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
	exit 1
esac
exit 0

# DP: Upstream patch bash31-010

			     BASH PATCH REPORT
			     =================

Bash-Release: 3.1
Patch-ID: bash31-010

Bug-Reported-by: vw@vonwolff.de
Bug-Reference-ID: <20060123135234.1AC2F1D596@wst07.vonwolff.de>
Bug-Reference-URL: http://lists.gnu.org/archive/html/bug-bash/2006-01/msg00090.html

Bug-Description:

There is a difference in behavior between bash-3.0 and bash-3.1 involving
parsing of single- and double-quoted strings occurring in old-style
command substitution.  The difference has to do with how backslashes are
processed.  This patch restores a measure of backwards compatibility while
the question of POSIX conformance and ultimately correct behavior is discussed.

THIS IS AN UPDATED PATCH.  USE THIS COMMAND TO REVERSE THE EFFECTS OF
THE ORIGINAL PATCH.  THE CURRENT DIRECTORY MUST BE THE BASH-3.1 SOURCE
DIRECTORY.

patch -p0 -R < bash31-010.orig

Then apply this patch as usual.

Patch:

*** ../bash-3.1/parse.y	Fri Nov 11 23:14:18 2005
--- parse.y	Thu Feb 23 08:21:12 2006
***************
*** 2716,2721 ****
--- 2723,2729 ----
  #define P_ALLOWESC	0x02
  #define P_DQUOTE	0x04
  #define P_COMMAND	0x08	/* parsing a command, so look for comments */
+ #define P_BACKQUOTE	0x10	/* parsing a backquoted command substitution */
  
  static char matched_pair_error;
  static char *
***************
*** 2725,2736 ****
       int *lenp, flags;
  {
    int count, ch, was_dollar, in_comment, check_comment;
!   int pass_next_character, nestlen, ttranslen, start_lineno;
    char *ret, *nestret, *ttrans;
    int retind, retsize, rflags;
  
    count = 1;
!   pass_next_character = was_dollar = in_comment = 0;
    check_comment = (flags & P_COMMAND) && qc != '\'' && qc != '"' && (flags & P_DQUOTE) == 0;
  
    /* RFLAGS is the set of flags we want to pass to recursive calls. */
--- 2733,2744 ----
       int *lenp, flags;
  {
    int count, ch, was_dollar, in_comment, check_comment;
!   int pass_next_character, backq_backslash, nestlen, ttranslen, start_lineno;
    char *ret, *nestret, *ttrans;
    int retind, retsize, rflags;
  
    count = 1;
!   pass_next_character = backq_backslash = was_dollar = in_comment = 0;
    check_comment = (flags & P_COMMAND) && qc != '\'' && qc != '"' && (flags & P_DQUOTE) == 0;
  
    /* RFLAGS is the set of flags we want to pass to recursive calls. */
***************
*** 2742,2752 ****
    start_lineno = line_number;
    while (count)
      {
! #if 0
!       ch = shell_getc ((qc != '\'' || (flags & P_ALLOWESC)) && pass_next_character == 0);
! #else
!       ch = shell_getc (qc != '\'' && pass_next_character == 0);
! #endif
        if (ch == EOF)
  	{
  	  free (ret);
--- 2750,2757 ----
    start_lineno = line_number;
    while (count)
      {
!       ch = shell_getc (qc != '\'' && pass_next_character == 0 && backq_backslash == 0);
! 
        if (ch == EOF)
  	{
  	  free (ret);
***************
*** 2771,2779 ****
  	  continue;
  	}
        /* Not exactly right yet */
!       else if (check_comment && in_comment == 0 && ch == '#' && (retind == 0 || ret[retind-1] == '\n' || whitespace (ret[retind -1])))
  	in_comment = 1;
  
        if (pass_next_character)		/* last char was backslash */
  	{
  	  pass_next_character = 0;
--- 2776,2791 ----
  	  continue;
  	}
        /* Not exactly right yet */
!       else if MBTEST(check_comment && in_comment == 0 && ch == '#' && (retind == 0 || ret[retind-1] == '\n' || whitespace (ret[retind - 1])))
  	in_comment = 1;
  
+       /* last char was backslash inside backquoted command substitution */
+       if (backq_backslash)
+ 	{
+ 	  backq_backslash = 0;
+ 	  /* Placeholder for adding special characters */
+ 	}
+ 
        if (pass_next_character)		/* last char was backslash */
  	{
  	  pass_next_character = 0;
***************
*** 2814,2819 ****
--- 2824,2831 ----
  	{
  	  if MBTEST((flags & P_ALLOWESC) && ch == '\\')
  	    pass_next_character++;
+ 	  else if MBTEST((flags & P_BACKQUOTE) && ch == '\\')
+ 	    backq_backslash++;
  	  continue;
  	}
  
***************
*** 2898,2904 ****
  	}
        else if MBTEST(qc == '`' && (ch == '"' || ch == '\'') && in_comment == 0)
  	{
! 	  nestret = parse_matched_pair (0, ch, ch, &nestlen, rflags);
  	  goto add_nestret;
  	}
        else if MBTEST(was_dollar && (ch == '(' || ch == '{' || ch == '['))	/* ) } ] */
--- 2910,2920 ----
  	}
        else if MBTEST(qc == '`' && (ch == '"' || ch == '\'') && in_comment == 0)
  	{
! 	  /* Add P_BACKQUOTE so backslash quotes the next character and
! 	     shell_getc does the right thing with \<newline>.  We do this for
! 	     a measure  of backwards compatibility -- it's not strictly the
! 	     right POSIX thing. */
! 	  nestret = parse_matched_pair (0, ch, ch, &nestlen, rflags|P_BACKQUOTE);
  	  goto add_nestret;
  	}
        else if MBTEST(was_dollar && (ch == '(' || ch == '{' || ch == '['))	/* ) } ] */
*** ../bash-3.1/patchlevel.h	Wed Jul 20 13:58:20 2005
--- patchlevel.h	Wed Dec  7 13:48:42 2005
***************
*** 26,30 ****
     looks for to find the patch level (for the sccs version string). */
  
! #define PATCHLEVEL 9
  
  #endif /* _PATCHLEVEL_H_ */
--- 26,30 ----
     looks for to find the patch level (for the sccs version string). */
  
! #define PATCHLEVEL 10
  
  #endif /* _PATCHLEVEL_H_ */