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strstr, strcasestr: replace on platforms with broken memchr

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* modules/strstr: Split into...
* modules/strstr-simple: ...new module that does not care about
performance, but does care about glibc bug.
* m4/strstr.m4 (gl_FUNC_STRSTR): Split...
(gl_FUNC_STRSTR_SIMPLE): ...into new macro, which replaces strstr
if platform memchr is broken, per Debian bug 521737.
* m4/strcasestr.m4 (gl_FUNC_STRCASESTR_SIMPLE): React to broken
memchr.
* m4/memchr.m4 (gl_FUNC_MEMCHR): Only expand once.
* doc/posix-functions/strstr.texi (strstr): Document the fix.
* doc/glibc-functions/strcasestr.texi (strcasestr): Likewise.
* modules/mountlist (Depends-on): Add strstr-simple.
* modules/gen-uni-tables (Depends-on): Likewise.
* modules/argz (Depends-on): Add strstr.

Signed-off-by: Eric Blake <ebb9@byu.net>
This commit is contained in:
Eric Blake
2009-06-16 06:14:05 -06:00
parent ea5142f736
commit e3e47d1710
11 changed files with 93 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
ChangeLog
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@@ -1,3 +1,21 @@
2009-06-17 Eric Blake <ebb9@byu.net>
strstr, strcasestr: replace on platforms with broken memchr
* modules/strstr: Split into...
* modules/strstr-simple: ...new module that does not care about
performance, but does care about glibc bug.
* m4/strstr.m4 (gl_FUNC_STRSTR): Split...
(gl_FUNC_STRSTR_SIMPLE): ...into new macro, which replaces strstr
if platform memchr is broken, per Debian bug 521737.
* m4/strcasestr.m4 (gl_FUNC_STRCASESTR_SIMPLE): React to broken
memchr.
* m4/memchr.m4 (gl_FUNC_MEMCHR): Only expand once.
* doc/posix-functions/strstr.texi (strstr): Document the fix.
* doc/glibc-functions/strcasestr.texi (strcasestr): Likewise.
* modules/mountlist (Depends-on): Add strstr-simple.
* modules/gen-uni-tables (Depends-on): Likewise.
* modules/argz (Depends-on): Add strstr.
2009-06-17 Bruno Haible <bruno@clisp.org>
* modules/posix_spawn-internal (Depends-on): Add errno.

7
doc/glibc-functions/strcasestr.texi
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@@ -9,7 +9,12 @@ or @code{strcasestr}:
@itemize
@item
This function is missing on some platforms:
AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, BeOS.
AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x,
mingw, BeOS.
@item
This function can trigger memchr bugs on some platforms:
glibc 2.10.
@end itemize
Portability problems fixed by Gnulib module @code{strcasestr}:

15
doc/posix-functions/strstr.texi
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@@ -4,14 +4,23 @@
POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/strstr.html}
Gnulib module: strstr
Gnulib module: strstr or strstr-simple
Portability problems fixed by Gnulib:
Portability problems fixed by either Gnulib module @code{strstr-simple}
or @code{strstr}:
@itemize
@item
This function can trigger memchr bugs on some platforms:
glibc 2.10.
@end itemize
Portability problems fixed by Gnulib @code{strstr}:
@itemize
@item
This function has quadratic instead of linear worst-case complexity on some
platforms:
glibc 2.8, MacOS X 10.3, FreeBSD 6.2, NetBSD 3.0, OpenBSD 4.0, AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw.
glibc 2.8, MacOS X 10.3, FreeBSD 6.2, NetBSD 3.0, OpenBSD 4.0, AIX
5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw.
@end itemize
Portability problems not fixed by Gnulib:

4
m4/memchr.m4
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@@ -1,10 +1,10 @@
# memchr.m4 serial 6
# memchr.m4 serial 7
dnl Copyright (C) 2002, 2003, 2004, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_MEMCHR],
AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
[
dnl Check for prerequisites for memory fence checks.
gl_FUNC_MMAP_ANON

11
m4/strcasestr.m4
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@@ -1,20 +1,25 @@
# strcasestr.m4 serial 12
dnl Copyright (C) 2005, 2007, 2008 Free Software Foundation, Inc.
# strcasestr.m4 serial 13
dnl Copyright (C) 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Check that strcasestr is present.
dnl Check that strcasestr is present and works.
AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
[
dnl Persuade glibc <string.h> to declare strcasestr().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_REQUIRE([gl_FUNC_MEMCHR])
AC_REPLACE_FUNCS([strcasestr])
if test $ac_cv_func_strcasestr = no; then
HAVE_STRCASESTR=0
gl_PREREQ_STRCASESTR
elif test "$gl_cv_func_memchr_works" != yes; then
REPLACE_STRCASESTR=1
AC_LIBOBJ([strcasestr])
gl_PREREQ_STRCASESTR
fi
]) # gl_FUNC_STRCASESTR_SIMPLE

19
m4/strstr.m4
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@@ -1,13 +1,24 @@
# strstr.m4 serial 5
dnl Copyright (C) 2008 Free Software Foundation, Inc.
# strstr.m4 serial 6
dnl Copyright (C) 2008, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Check that strstr is efficient.
AC_DEFUN([gl_FUNC_STRSTR],
dnl Check that strstr works.
AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
[
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_REQUIRE([gl_FUNC_MEMCHR])
if test "$gl_cv_func_memchr_works" != yes; then
REPLACE_STRSTR=1
AC_LIBOBJ([strstr])
fi
]) # gl_FUNC_STRSTR_SIMPLE
dnl Additionally, check that strstr is efficient.
AC_DEFUN([gl_FUNC_STRSTR],
[
AC_REQUIRE([gl_FUNC_STRSTR_SIMPLE])
AC_CACHE_CHECK([whether strstr works in linear time],
[gl_cv_func_strstr_linear],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[

1
modules/argz
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@@ -12,6 +12,7 @@ mempcpy
stpcpy
strndup
strnlen
strstr
configure.ac:
gl_FUNC_ARGZ

1
modules/gen-uni-tables
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@@ -10,6 +10,7 @@ lib/unictype/3levelbit.h
Depends-on:
memcmp
strdup
strstr-simple
configure.ac:

1
modules/mountlist
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@@ -11,6 +11,7 @@ m4/mountlist.m4
Depends-on:
stdbool
stdint
strstr-simple
xalloc
configure.ac:

9
modules/strstr
View File

@@ -2,19 +2,12 @@ Description:
strstr() function: efficiently locate first substring in a buffer.
Files:
lib/str-two-way.h
lib/strstr.c
m4/strstr.m4
Depends-on:
string
stdbool
memchr
memcmp
strstr-simple
configure.ac:
gl_FUNC_STRSTR
gl_STRING_MODULE_INDICATOR([strstr])
Makefile.am:

28
modules/strstr-simple Normal file
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@@ -0,0 +1,28 @@
Description:
strstr() function: locate first substring in a buffer.
Files:
lib/str-two-way.h
lib/strstr.c
m4/strstr.m4
Depends-on:
string
stdbool
memchr
memcmp
configure.ac:
gl_FUNC_STRSTR_SIMPLE
gl_STRING_MODULE_INDICATOR([strstr])
Makefile.am:
Include:
<string.h>
License:
LGPLv2+
Maintainer:
all, Eric Blake