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new module 'strerror_r-posix' (was: Re: strerror thread-safety?)
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From: |
Bruno Haible |
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Subject: |
new module 'strerror_r-posix' (was: Re: strerror thread-safety?) |
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Date: |
Tue, 9 Nov 2010 03:09:51 +0100 |
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User-agent: |
KMail/1.9.9 |
Eric Blake wrote:
> strerror_r has its own set of portability problems, since the glibc
> signature disagrees with the POSIX signature. It also has not yet been
> ported to gnulib (in either the POSIX or glibc variant). That might be
> a useful project to tackle first.
Here's a draft proposal: A new module 'strerror_r-posix'. I wouldn't want
to call it 'strerror_r' because that would be misunderstandable.
2010-11-09 Bruno Haible <address@hidden>
New module 'strerror_r-posix'.
* lib/string.in.h (strerror_r): New declaration.
* lib/strerror_r.c: New file.
* m4/strerror_r.m4: New file.
* m4/string_h.m4 (gl_HEADER_STRING_H_BODY): Check for the declaration
of strerror_r.
(gl_HEADER_STRING_H_DEFAULTS): Initialize GNULIB_STRERROR_R,
HAVE_DECL_STRERROR_R, REPLACE_STRERROR_R.
* modules/strerror_r-posix: New file.
* modules/string (Makefile.am): Substitute GNULIB_STRERROR_R,
HAVE_DECL_STRERROR_R, REPLACE_STRERROR_R.
* doc/posix-functions/strerror_r.texi: Mention the new module and the
portability problems.
Tests for module 'strerror_r-posix'.
* modules/strerror_r-posix-tests: New file.
* tests/test-strerror_r.c: New file.
* tests/test-string-c++.cc: Check the signature of strerror_r.
--- lib/string.in.h.orig Tue Nov 9 02:53:13 2010
+++ lib/string.in.h Tue Nov 9 01:20:43 2010
@@ -902,6 +902,33 @@
"use gnulib module strerror to guarantee non-NULL result");
#endif
+/* Map any int, typically from errno, into an error message. Multithread-safe.
+ Uses the POSIX declaration, not the glibc declaration. */
+#if @GNULIB_STRERROR_R@
+# if @REPLACE_STRERROR_R@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# undef strerror_r
+# define strerror_r rpl_strerror_r
+# endif
+_GL_FUNCDECL_RPL (strerror_r, int, (int errnum, char *buf, size_t buflen)
+ _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (strerror_r, int, (int errnum, char *buf, size_t buflen));
+# else
+# if address@hidden@
+_GL_FUNCDECL_SYS (strerror_r, int, (int errnum, char *buf, size_t buflen)
+ _GL_ARG_NONNULL ((2)));
+# endif
+_GL_CXXALIAS_SYS (strerror_r, int, (int errnum, char *buf, size_t buflen));
+# endif
+_GL_CXXALIASWARN (strerror_r);
+#elif defined GNULIB_POSIXCHECK
+# undef strerror_r
+# if HAVE_RAW_DECL_STRERROR_R
+_GL_WARN_ON_USE (strerror_r, "strerror_r is unportable - "
+ "use gnulib module strerror_r-posix for portability");
+# endif
+#endif
+
#if @GNULIB_STRSIGNAL@
# if @REPLACE_STRSIGNAL@
# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
============================== lib/strerror_r.c ==============================
/* strerror_r.c --- POSIX compatible system error routine
Copyright (C) 2010 Free Software Foundation, Inc.
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <address@hidden>, 2010. */
#include <config.h>
/* Specification. */
#include <string.h>
#include <errno.h>
#if __GLIBC__ >= 2 && HAVE___XPG_STRERROR_R && 0 /* glibc >= 2.3.4 */
int
strerror_r (int errnum, char *buf, size_t buflen)
{
extern int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
int ret = __xpg_strerror_r (errnum, buf, buflen);
return (ret < 0 ? errno : 0);
}
#else
# include "glthread/lock.h"
/* Use strerror(), with locking. */
/* This lock protects the buffer returned by strerror(). We assume that
no other uses of strerror() exist in the program. */
gl_lock_define_initialized(static, strerror_lock)
int
strerror_r (int errnum, char *buf, size_t buflen)
{
gl_lock_lock (strerror_lock);
{
char *errmsg = strerror (errnum);
size_t len = strlen (errmsg);
int ret;
if (len < buflen)
{
memcpy (buf, errmsg, len + 1);
ret = 0;
}
else
ret = ERANGE;
gl_lock_unlock (strerror_lock);
return ret;
}
}
#endif
============================== m4/strerror_r.m4 ==============================
# strerror_r.m4 serial 1
dnl Copyright (C) 2002, 2007-2010 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_STRERROR_R],
[
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_REQUIRE([gl_HEADER_ERRNO_H])
dnl Persuade Solaris <string.h> to declare strerror_r().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Some systems don't declare strerror_r() if _THREAD_SAFE and _REENTRANT
dnl are not defined.
AC_CHECK_DECLS_ONCE([strerror_r])
if test $ac_cv_have_decl_strerror_r = no; then
HAVE_DECL_STRERROR_R=0
fi
AC_CHECK_FUNCS([strerror_r])
if test $ac_cv_func_strerror_r = yes; then
if test -z "$ERRNO_H"; then
AC_CACHE_CHECK([for strerror_r with POSIX signature],
[gl_cv_func_strerror_r_posix_signature],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <string.h>
int strerror_r (int, char *, size_t);
]],
[[return strerror (0);]])],
[gl_cv_func_strerror_r_posix_signature=yes],
[gl_cv_func_strerror_r_posix_signature=no])
])
if test $gl_cv_func_strerror_r_posix_signature != yes; then
dnl glibc >= 2.3.4 has a function __xpg_strerror_r.
AC_CHECK_FUNCS([__xpg_strerror_r])
dnl The system's strerror() has a wrong signature. Replace it.
REPLACE_STRERROR_R=1
fi
else
dnl The system's strerror_r() cannot know about the new errno values we
dnl add to <errno.h>. Replace it.
REPLACE_STRERROR_R=1
fi
fi
if test $HAVE_DECL_STRERROR_R = 0 || test $REPLACE_STRERROR_R = 1; then
AC_LIBOBJ([strerror_r])
gl_PREREQ_STRERROR_R
fi
])
# Prerequisites of lib/strerror_r.c.
AC_DEFUN([gl_PREREQ_STRERROR_R], [
:
])
--- m4/string_h.m4.orig Tue Nov 9 02:53:13 2010
+++ m4/string_h.m4 Tue Nov 9 01:20:59 2010
@@ -5,7 +5,7 @@
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
-# serial 17
+# serial 18
# Written by Paul Eggert.
@@ -28,8 +28,8 @@
gl_WARN_ON_USE_PREPARE([[#include <string.h>
]],
[memmem mempcpy memrchr rawmemchr stpcpy stpncpy strchrnul strdup
- strncat strndup strnlen strpbrk strsep strcasestr strtok_r strsignal
- strverscmp])
+ strncat strndup strnlen strpbrk strsep strcasestr strtok_r strerror_r
+ strsignal strverscmp])
])
AC_DEFUN([gl_STRING_MODULE_INDICATOR],
@@ -75,6 +75,7 @@
GNULIB_MBSSEP=0; AC_SUBST([GNULIB_MBSSEP])
GNULIB_MBSTOK_R=0; AC_SUBST([GNULIB_MBSTOK_R])
GNULIB_STRERROR=0; AC_SUBST([GNULIB_STRERROR])
+ GNULIB_STRERROR_R=0; AC_SUBST([GNULIB_STRERROR_R])
GNULIB_STRSIGNAL=0; AC_SUBST([GNULIB_STRSIGNAL])
GNULIB_STRVERSCMP=0; AC_SUBST([GNULIB_STRVERSCMP])
HAVE_MBSLEN=0; AC_SUBST([HAVE_MBSLEN])
@@ -94,6 +95,7 @@
HAVE_STRSEP=1; AC_SUBST([HAVE_STRSEP])
HAVE_STRCASESTR=1; AC_SUBST([HAVE_STRCASESTR])
HAVE_DECL_STRTOK_R=1; AC_SUBST([HAVE_DECL_STRTOK_R])
+ HAVE_DECL_STRERROR_R=1; AC_SUBST([HAVE_DECL_STRERROR_R])
HAVE_DECL_STRSIGNAL=1; AC_SUBST([HAVE_DECL_STRSIGNAL])
HAVE_STRVERSCMP=1; AC_SUBST([HAVE_STRVERSCMP])
REPLACE_MEMCHR=0; AC_SUBST([REPLACE_MEMCHR])
@@ -103,6 +105,7 @@
REPLACE_STRSTR=0; AC_SUBST([REPLACE_STRSTR])
REPLACE_STRCASESTR=0; AC_SUBST([REPLACE_STRCASESTR])
REPLACE_STRERROR=0; AC_SUBST([REPLACE_STRERROR])
+ REPLACE_STRERROR_R=0; AC_SUBST([REPLACE_STRERROR_R])
REPLACE_STRNCAT=0; AC_SUBST([REPLACE_STRNCAT])
REPLACE_STRNDUP=0; AC_SUBST([REPLACE_STRNDUP])
REPLACE_STRNLEN=0; AC_SUBST([REPLACE_STRNLEN])
========================== modules/strerror_r-posix ==========================
Description:
strerror_r() function: get string describing error code.
Files:
lib/strerror_r.c
m4/strerror_r.m4
Depends-on:
string
errno
extensions
lock
configure.ac:
gl_FUNC_STRERROR_R
gl_STRING_MODULE_INDICATOR([strerror_r])
Makefile.am:
Include:
<string.h>
License:
LGPL
Maintainer:
Bruno Haible
--- modules/string.orig Tue Nov 9 02:53:13 2010
+++ modules/string Tue Nov 9 01:21:10 2010
@@ -60,6 +60,7 @@
-e 's|@''GNULIB_STRCASESTR''@|$(GNULIB_STRCASESTR)|g' \
-e 's|@''GNULIB_STRTOK_R''@|$(GNULIB_STRTOK_R)|g' \
-e 's|@''GNULIB_STRERROR''@|$(GNULIB_STRERROR)|g' \
+ -e 's|@''GNULIB_STRERROR_R''@|$(GNULIB_STRERROR_R)|g' \
-e 's|@''GNULIB_STRSIGNAL''@|$(GNULIB_STRSIGNAL)|g' \
-e 's|@''GNULIB_STRVERSCMP''@|$(GNULIB_STRVERSCMP)|g' \
< $(srcdir)/string.in.h | \
@@ -79,6 +80,7 @@
-e 's|@''HAVE_STRSEP''@|$(HAVE_STRSEP)|g' \
-e 's|@''HAVE_STRCASESTR''@|$(HAVE_STRCASESTR)|g' \
-e 's|@''HAVE_DECL_STRTOK_R''@|$(HAVE_DECL_STRTOK_R)|g' \
+ -e 's|@''HAVE_DECL_STRERROR_R''@|$(HAVE_DECL_STRERROR_R)|g' \
-e 's|@''HAVE_DECL_STRSIGNAL''@|$(HAVE_DECL_STRSIGNAL)|g' \
-e 's|@''HAVE_STRVERSCMP''@|$(HAVE_STRVERSCMP)|g' \
-e 's|@''REPLACE_STPNCPY''@|$(REPLACE_STPNCPY)|g' \
@@ -88,6 +90,7 @@
-e 's|@''REPLACE_STRDUP''@|$(REPLACE_STRDUP)|g' \
-e 's|@''REPLACE_STRSTR''@|$(REPLACE_STRSTR)|g' \
-e 's|@''REPLACE_STRERROR''@|$(REPLACE_STRERROR)|g' \
+ -e 's|@''REPLACE_STRERROR_R''@|$(REPLACE_STRERROR_R)|g' \
-e 's|@''REPLACE_STRNCAT''@|$(REPLACE_STRNCAT)|g' \
-e 's|@''REPLACE_STRNDUP''@|$(REPLACE_STRNDUP)|g' \
-e 's|@''REPLACE_STRNLEN''@|$(REPLACE_STRNLEN)|g' \
--- doc/posix-functions/strerror_r.texi.orig Tue Nov 9 02:53:13 2010
+++ doc/posix-functions/strerror_r.texi Tue Nov 9 01:19:22 2010
@@ -4,14 +4,10 @@
POSIX specification:@*
@url{http://www.opengroup.org/onlinepubs/9699919799/functions/strerror_r.html}
-Gnulib module: ---
+Gnulib module: strerror_r-posix
Portability problems fixed by Gnulib:
@itemize
address@hidden itemize
-
-Portability problems not fixed by Gnulib:
address@hidden
@item
This function is missing on some platforms:
NetBSD 3.0, HP-UX 11, IRIX 6.5, Solaris 9, mingw.
@@ -24,4 +20,16 @@
@smallexample
char *s = strerror_r (err, buf, buflen);
@end smallexample
address@hidden
+The third argument is of type @code{int} instead of @code{size_t} on some
+platforms:
+AIX 5.1, HP-UX 11, OSF/1 5.1.
address@hidden
+This function does not support the error values that are specified by POSIX
+but not defined by the system, on some platforms:
+OpenBSD 4.0, OSF/1 5.1, NonStop Kernel, Cygwin 1.5.x.
address@hidden itemize
+
+Portability problems not fixed by Gnulib:
address@hidden
@end itemize
======================= modules/strerror_r-posix-tests =======================
Files:
tests/test-strerror_r.c
tests/signature.h
tests/macros.h
Depends-on:
configure.ac:
Makefile.am:
TESTS += test-strerror_r
check_PROGRAMS += test-strerror_r
=========================== tests/test-strerror_r.c ===========================
/* Test of strerror_r() function.
Copyright (C) 2007-2010 Free Software Foundation, Inc.
This program 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, or (at your option)
any later version.
This program 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 this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <config.h>
#include <string.h>
#include "signature.h"
SIGNATURE_CHECK (strerror_r, int, (int, char *, size_t));
#include <errno.h>
#include "macros.h"
int
main (void)
{
char buf[100];
int ret;
/* Test results with valid errnum and enough room. */
buf[0] = '\0';
ASSERT (strerror_r (EACCES, buf, sizeof (buf)) == 0);
ASSERT (buf[0] != '\0');
buf[0] = '\0';
ASSERT (strerror_r (ETIMEDOUT, buf, sizeof (buf)) == 0);
ASSERT (buf[0] != '\0');
buf[0] = '\0';
ASSERT (strerror_r (EOVERFLOW, buf, sizeof (buf)) == 0);
ASSERT (buf[0] != '\0');
/* Test results with out-of-range errnum and enough room. */
buf[0] = '\0';
ret = strerror_r (0, buf, sizeof (buf));
ASSERT (ret == 0 || ret == EINVAL);
if (ret == 0)
ASSERT (buf[0] != '\0');
buf[0] = '\0';
ret = strerror_r (-3, buf, sizeof (buf));
ASSERT (ret == 0 || ret == EINVAL);
if (ret == 0)
ASSERT (buf[0] != '\0');
/* Test results with a too small buffer. */
ASSERT (strerror_r (EACCES, buf, sizeof (buf)) == 0);
{
size_t len = strlen (buf);
size_t i;
for (i = 0; i <= len; i++)
{
strcpy (buf, "BADFACE");
ASSERT (strerror_r (EACCES, buf, i) == ERANGE);
ASSERT (strcmp (buf, "BADFACE") == 0);
}
}
return 0;
}
--- tests/test-string-c++.cc.orig Tue Nov 9 02:53:13 2010
+++ tests/test-string-c++.cc Tue Nov 9 01:00:32 2010
@@ -126,6 +126,10 @@
SIGNATURE_CHECK (GNULIB_NAMESPACE::strerror, char *, (int));
#endif
+#if GNULIB_TEST_STRERROR_R
+SIGNATURE_CHECK (GNULIB_NAMESPACE::strerror_r, int, (int, char *, size_t));
+#endif
+
#if GNULIB_TEST_STRSIGNAL
SIGNATURE_CHECK (GNULIB_NAMESPACE::strsignal, char *, (int));
#endif