Re: [2.23 PATCH] Desupport regexp.h (bug 18681)

[Zack Weinberg <zackw at panix dot com>]

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On 08/05/2015 10:40 PM, Mike Frysinger wrote:
> On 12 Jul 2015 15:27, Zack Weinberg wrote:
>> I posted this a couple weeks ago, but now that the branch has been
>> cut, `SHLIB_COMPAT(GLIBC_2_0, GLIBC_2_23)` compiles, so I've actually
>> tested it. ;-)  Also, I merged in the corrections to NEWS and the
>> comment at the top of regexp.h, which I posted separately for the
>> 2.22 branch.  And hopefully it will not get mangled this time.
>
> i merged the NEWS/comment correction by itself to keep the
> master/branch in sync, so you'll have to rebase.

OK, rebased patch follows.  Thanks for the quick turnaround.

zw

	* misc/regexp.h: This interface is no longer supported.
	Remove all contents, leaving only an #error directive.
	* misc/regexp.c (loc1, loc2, locs, step, advance):
	Demote to compatibility symbols.
- ---
 NEWS          |   6 +-
 misc/regexp.c |  29 +++++++--
 misc/regexp.h | 203 +---------------------------------------------------------
 3 files changed, 30 insertions(+), 208 deletions(-)

diff --git a/NEWS b/NEWS
index e3c2351..794a515 100644
- --- a/NEWS
+++ b/NEWS
@@ -8,7 +8,11 @@ using `glibc' in the "product" field.
 Version 2.23
 
 * The following bugs are resolved with this release:
- -  16519, 18265, 18525, 18647, 18661.
+
+  16519, 18265, 18525, 18647, 18661, 18681.
+
+* The obsolete header <regexp.h> has been removed.  Programs that require
+  this header must be updated to use <regex.h> instead.
 
 Version 2.22
 
diff --git a/misc/regexp.c b/misc/regexp.c
index ee7d572..ef5e18b 100644
- --- a/misc/regexp.c
+++ b/misc/regexp.c
@@ -1,4 +1,4 @@
- -/* Define function and variables for the obsolete <regexp.h> interface.
+/* Compatibility symbols for the obsolete <regexp.h> interface.
    Copyright (C) 1996-2015 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
@@ -17,17 +17,27 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
- -/* We don't include regexp.h here because of the macros it requires, and
- -   because it now contains an unconditional #warning.  */
+/* regexp.h now contains only an #error directive, so it cannot be
+   used in this file.
+
+   The function that would produce an 'expbuf' to use as the second
+   argument to 'step' and 'advance' was defined only in regexp.h,
+   as its definition depended on macros defined by the user.  */
 
 #include <regex.h>
+#include <shlib-compat.h>
+
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
 
 /* Define the variables used for the interface.  */
 char *loc1;
 char *loc2;
+compat_symbol (libc, loc1, loc1, GLIBC_2_0);
+compat_symbol (libc, loc2, loc2, GLIBC_2_0);
 
 /* Although we do not support the use we define this variable as well.  */
 char *locs;
+compat_symbol (libc, locs, locs, GLIBC_2_0);
 
 
 /* Find the next match in STRING.  The compiled regular expression is
@@ -35,7 +45,8 @@ char *locs;
    first character matched and `loc2' points to the next unmatched
    character.  */
 int
- -__step (const char *string, const char *expbuf)
+weak_function attribute_compat_text_section
+step (const char *string, const char *expbuf)
 {
   regmatch_t match;	/* We only need info about the full match.  */
 
@@ -50,14 +61,15 @@ __step (const char *string, const char *expbuf)
   loc2 = (char *) string + match.rm_eo;
   return 1;
 }
- -weak_alias (__step, step)
+compat_symbol (libc, step, step, GLIBC_2_0);
 
 
 /* Match the beginning of STRING with the compiled regular expression
    in EXPBUF.  If the match is successful `loc2' will contain the
    position of the first unmatched character.  */
 int
- -__advance (const char *string, const char *expbuf)
+weak_function attribute_compat_text_section
+advance (const char *string, const char *expbuf)
 {
   regmatch_t match;	/* We only need info about the full match.  */
 
@@ -74,4 +86,7 @@ __advance (const char *string, const char *expbuf)
   loc2 = (char *) string + match.rm_eo;
   return 1;
 }
- -weak_alias (__advance, advance)
+compat_symbol (libc, advance, advance, GLIBC_2_0);
+
+
+#endif /* SHLIB_COMPAT (2.0, 2.23) */
diff --git a/misc/regexp.h b/misc/regexp.h
index 42394f7..9f5c413 100644
- --- a/misc/regexp.h
+++ b/misc/regexp.h
@@ -25,206 +25,9 @@
    were encouraged to use <regex.h> instead.  It was officially
    withdrawn from the standard in Issue 6 (aka POSIX.1-2001).
 
- -   This header is provided only for backward compatibility.
- -   It will be removed in the next release of the GNU C Library.
- -   New code should use <regex.h> instead.  */
+   The GNU C Library provided this header through version 2.22. */
 
- -#warning "<regexp.h> will be removed in the next release of the GNU C Library."
- -#warning "Please update your code to use <regex.h> instead (no trailing 'p')."
- -
- -#include <features.h>
- -#include <alloca.h>
- -#include <regex.h>
- -#include <stdlib.h>
- -#include <string.h>
- -
- -/* The implementation provided here emulates the needed functionality
- -   by mapping to the POSIX regular expression matcher.  The interface
- -   for the here included function is weird (this really is a harmless
- -   word).
- -
- -   The user has to provide six macros before this header file can be
- -   included:
- -
- -   INIT		Declarations vor variables which can be used by the
- -		other macros.
- -
- -   GETC()	Return the value of the next character in the regular
- -		expression pattern.  Successive calls should return
- -		successive characters.
- -
- -   PEEKC()	Return the value of the next character in the regular
- -		expression pattern.  Immediately successive calls to
- -		PEEKC() should return the same character which should
- -		also be the next character returned by GETC().
- -
- -   UNGETC(c)	Cause `c' to be returned by the next call to GETC() and
- -		PEEKC().
- -
- -   RETURN(ptr)	Used for normal exit of the `compile' function.  `ptr'
- -		is a pointer to the character after the last character of
- -		the compiled regular expression.
- -
- -   ERROR(val)	Used for abnormal return from `compile'.  `val' is the
- -		error number.  The error codes are:
- -		11	Range endpoint too large.
- -		16	Bad number.
- -		25	\digit out of range.
- -		36	Illegal or missing delimiter.
- -		41	No remembered search string.
- -		42	\( \) imbalance.
- -		43	Too many \(.
- -		44	More tan two numbers given in \{ \}.
- -		45	} expected after \.
- -		46	First number exceeds second in \{ \}.
- -		49	[ ] imbalance.
- -		50	Regular expression overflow.
- -
- -  */
- -
- -__BEGIN_DECLS
- -
- -/* Interface variables.  They contain the results of the successful
- -   calls to `setp' and `advance'.  */
- -extern char *loc1;
- -extern char *loc2;
- -
- -/* The use of this variable in the `advance' function is not
- -   supported.  */
- -extern char *locs;
- -
- -
- -#ifndef __DO_NOT_DEFINE_COMPILE
- -/* Get and compile the user supplied pattern up to end of line or
- -   string or until EOF is seen, whatever happens first.  The result is
- -   placed in the buffer starting at EXPBUF and delimited by ENDBUF.
- -
- -   This function cannot be defined in the libc itself since it depends
- -   on the macros.  */
- -char *
- -compile (char *__restrict instring, char *__restrict expbuf,
- -	 const char *__restrict endbuf, int eof)
- -{
- -  char *__input_buffer = NULL;
- -  size_t __input_size = 0;
- -  size_t __current_size = 0;
- -  int __ch;
- -  int __error;
- -  INIT
- -
- -  /* Align the expression buffer according to the needs for an object
- -     of type `regex_t'.  Then check for minimum size of the buffer for
- -     the compiled regular expression.  */
- -  regex_t *__expr_ptr;
- -# if defined __GNUC__ && __GNUC__ >= 2
- -  const size_t __req = __alignof__ (regex_t *);
- -# else
- -  /* How shall we find out?  We simply guess it and can change it is
- -     this really proofs to be wrong.  */
- -  const size_t __req = 8;
- -# endif
- -  expbuf += __req;
- -  expbuf -= (expbuf - ((char *) 0)) % __req;
- -  if (endbuf < expbuf + sizeof (regex_t))
- -    {
- -      ERROR (50);
- -    }
- -  __expr_ptr = (regex_t *) expbuf;
- -  /* The remaining space in the buffer can be used for the compiled
- -     pattern.  */
- -  __expr_ptr->__REPB_PREFIX (buffer) = expbuf + sizeof (regex_t);
- -  __expr_ptr->__REPB_PREFIX (allocated)
- -    = endbuf - (char *) __expr_ptr->__REPB_PREFIX (buffer);
- -
- -  while ((__ch = (GETC ())) != eof)
- -    {
- -      if (__ch == '\0' || __ch == '\n')
- -	{
- -	  UNGETC (__ch);
- -	  break;
- -	}
- -
- -      if (__current_size + 1 >= __input_size)
- -	{
- -	  size_t __new_size = __input_size ? 2 * __input_size : 128;
- -	  char *__new_room = (char *) alloca (__new_size);
- -	  /* See whether we can use the old buffer.  */
- -	  if (__new_room + __new_size == __input_buffer)
- -	    {
- -	      __input_size += __new_size;
- -	      __input_buffer = (char *) memcpy (__new_room, __input_buffer,
- -					       __current_size);
- -	    }
- -	  else if (__input_buffer + __input_size == __new_room)
- -	    __input_size += __new_size;
- -	  else
- -	    {
- -	      __input_size = __new_size;
- -	      __input_buffer = (char *) memcpy (__new_room, __input_buffer,
- -						__current_size);
- -	    }
- -	}
- -      __input_buffer[__current_size++] = __ch;
- -    }
- -  if (__current_size)
- -    __input_buffer[__current_size++] = '\0';
- -  else
- -    __input_buffer = "";
- -
- -  /* Now compile the pattern.  */
- -  __error = regcomp (__expr_ptr, __input_buffer, REG_NEWLINE);
- -  if (__error != 0)
- -    /* Oh well, we have to translate POSIX error codes.  */
- -    switch (__error)
- -      {
- -      case REG_BADPAT:
- -      case REG_ECOLLATE:
- -      case REG_ECTYPE:
- -      case REG_EESCAPE:
- -      case REG_BADRPT:
- -      case REG_EEND:
- -      case REG_ERPAREN:
- -      default:
- -	/* There is no matching error code.  */
- -	ERROR (36);
- -      case REG_ESUBREG:
- -	ERROR (25);
- -      case REG_EBRACK:
- -	ERROR (49);
- -      case REG_EPAREN:
- -	ERROR (42);
- -      case REG_EBRACE:
- -	ERROR (44);
- -      case REG_BADBR:
- -	ERROR (46);
- -      case REG_ERANGE:
- -	ERROR (11);
- -      case REG_ESPACE:
- -      case REG_ESIZE:
- -	ERROR (50);
- -      }
- -
- -  /* Everything is ok.  */
- -  RETURN ((char *) (__expr_ptr->__REPB_PREFIX (buffer)
- -		    + __expr_ptr->__REPB_PREFIX (used)));
- -}
- -#endif
- -
- -
- -/* Find the next match in STRING.  The compiled regular expression is
- -   found in the buffer starting at EXPBUF.  `loc1' will return the
- -   first character matched and `loc2' points to the next unmatched
- -   character.  */
- -extern int step (const char *__restrict __string,
- -		 const char *__restrict __expbuf) __THROW;
- -
- -/* Match the beginning of STRING with the compiled regular expression
- -   in EXPBUF.  If the match is successful `loc2' will contain the
- -   position of the first unmatched character.  */
- -extern int advance (const char *__restrict __string,
- -		    const char *__restrict __expbuf) __THROW;
- -
- -
- -__END_DECLS
+#error "The GNU C Library no longer implements <regexp.h>."
+#error "Please update your code to use <regex.h> instead (no trailing 'p')."
 
 #endif /* regexp.h */
- -- 
2.5.0

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