Mercurial > gnulib
changeset 15622:814138b4cfed
fdatasync: new module
At least libvirt would like to use the lighter-weight fdatasync
on platforms where it is supported, while still guaranteeing full
sync (via the heavy-weight fsync fallback) on all platforms.
I've got an open question to the Austin Group, since the POSIX 2008
wording is self-contradictory (unlike fsync, fdatasync requires
EBADF on non-writable fds, but still mentions that read() errors
must be propagated). I can see how fsync() would affect atime after
read() while fdatasync() can skip that, explaining why fdatasync()
might have the EBADF requirement, but on the other hand, that prevents
an implementation (like ours) where fdatasync is a straight alias of
fsync. At any rate, glibc allows fdatasync on read-only fds.
* modules/fsync (Description): Document difference to fdatasync.
* modules/fdatasync: New module.
* m4/fdatasync.m4 (gl_FUNC_FDATASYNC): New file.
* lib/fdatasync.c (fdatasync): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H, gl_UNISTD_H_DEFAULTS): Set up
defaults.
* modules/unistd (Makefile.am): Set witnesses.
* lib/unistd.in.h (fdatasync): Declare.
* MODULES.html.sh: Document it.
* doc/posix-functions/fdatasync.texi (fdatasync): Likewise.
* modules/fdatasync-tests: New test.
* tests/test-fdatasync.c: Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Fri, 16 Sep 2011 09:59:23 -0600 |
parents | 44827bcbe6ca |
children | 1add0c3b0f4b |
files | ChangeLog MODULES.html.sh doc/posix-functions/fdatasync.texi lib/fdatasync.c lib/unistd.in.h m4/fdatasync.m4 m4/unistd_h.m4 modules/fdatasync modules/fdatasync-tests modules/fsync modules/unistd tests/test-fdatasync.c |
diffstat | 12 files changed, 193 insertions(+), 9 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog Fri Sep 16 10:28:13 2011 -0600 +++ b/ChangeLog Fri Sep 16 09:59:23 2011 -0600 @@ -1,3 +1,19 @@ +2011-09-16 Eric Blake <eblake@redhat.com> + + fdatasync: new module + * modules/fsync (Description): Document difference to fdatasync. + * modules/fdatasync: New module. + * m4/fdatasync.m4 (gl_FUNC_FDATASYNC): New file. + * lib/fdatasync.c (fdatasync): Likewise. + * m4/unistd_h.m4 (gl_UNISTD_H, gl_UNISTD_H_DEFAULTS): Set up + defaults. + * modules/unistd (Makefile.am): Set witnesses. + * lib/unistd.in.h (fdatasync): Declare. + * MODULES.html.sh: Document it. + * doc/posix-functions/fdatasync.texi (fdatasync): Likewise. + * modules/fdatasync-tests: New test. + * tests/test-fdatasync.c: Likewise. + 2011-09-16 Eric Blake <eblake@redhat.com> test-fsync: enhance tests
--- a/MODULES.html.sh Fri Sep 16 10:28:13 2011 -0600 +++ b/MODULES.html.sh Fri Sep 16 09:59:23 2011 -0600 @@ -2356,6 +2356,7 @@ func_module fclose func_module fcntl-h func_module fcntl + func_module fdatasync func_module flock func_module fopen func_module fprintf-posix
--- a/doc/posix-functions/fdatasync.texi Fri Sep 16 10:28:13 2011 -0600 +++ b/doc/posix-functions/fdatasync.texi Fri Sep 16 09:59:23 2011 -0600 @@ -4,15 +4,15 @@ POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html} -Gnulib module: --- +Gnulib module: fdatasync Portability problems fixed by Gnulib: @itemize -@end itemize - -Portability problems not fixed by Gnulib: -@itemize @item This function is missing on some platforms: MacOS X 10.5, FreeBSD 6.0, OpenBSD 3.8, Minix 3.1.8, IRIX 5.3, Solaris 2.4, mingw, MSVC 9, Interix 3.5, BeOS. @end itemize + +Portability problems not fixed by Gnulib: +@itemize +@end itemize
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/lib/fdatasync.c Fri Sep 16 09:59:23 2011 -0600 @@ -0,0 +1,25 @@ +/* Emulate fdatasync on platforms that lack it. + + Copyright (C) 2011 Free Software Foundation, Inc. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser 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/>. */ + +#include <config.h> +#include <unistd.h> + +int +fdatasync (int fd) +{ + return fsync (fd); +}
--- a/lib/unistd.in.h Fri Sep 16 10:28:13 2011 -0600 +++ b/lib/unistd.in.h Fri Sep 16 09:59:23 2011 -0600 @@ -484,8 +484,27 @@ #endif +#if @GNULIB_FDATASYNC@ +/* Synchronize changes to a file. + Return 0 if successful, otherwise -1 and errno set. + See POSIX:2001 specification + <http://www.opengroup.org/susv3xsh/fdatasync.html>. */ +# if !@HAVE_FDATASYNC@ +_GL_FUNCDECL_SYS (fdatasync, int, (int fd)); +# endif +_GL_CXXALIAS_SYS (fdatasync, int, (int fd)); +_GL_CXXALIASWARN (fdatasync); +#elif defined GNULIB_POSIXCHECK +# undef fdatasync +# if HAVE_RAW_DECL_FDATASYNC +_GL_WARN_ON_USE (fdatasync, "fdatasync is unportable - " + "use gnulib module fdatasync for portability"); +# endif +#endif + + #if @GNULIB_FSYNC@ -/* Synchronize changes to a file. +/* Synchronize changes, including metadata, to a file. Return 0 if successful, otherwise -1 and errno set. See POSIX:2001 specification <http://www.opengroup.org/susv3xsh/fsync.html>. */
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/m4/fdatasync.m4 Fri Sep 16 09:59:23 2011 -0600 @@ -0,0 +1,14 @@ +# fdatasync.m4 serial 1 +dnl Copyright (C) 2008-2011 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_FDATASYNC], +[ + AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) + AC_CHECK_FUNCS_ONCE([fdatasync]) + if test $ac_cv_func_fdatasync = no; then + HAVE_FDATASYNC=0 + fi +])
--- a/m4/unistd_h.m4 Fri Sep 16 10:28:13 2011 -0600 +++ b/m4/unistd_h.m4 Fri Sep 16 09:59:23 2011 -0600 @@ -1,4 +1,4 @@ -# unistd_h.m4 serial 58 +# unistd_h.m4 serial 59 dnl Copyright (C) 2006-2011 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -40,7 +40,7 @@ # endif #endif ]], [chown dup2 dup3 environ euidaccess faccessat fchdir fchownat - fsync ftruncate getcwd getdomainname getdtablesize getgroups + fdatasync fsync ftruncate getcwd getdomainname getdtablesize getgroups gethostname getlogin getlogin_r getpagesize getusershell setusershell endusershell group_member lchown link linkat lseek pipe pipe2 pread pwrite readlink readlinkat rmdir sleep symlink symlinkat ttyname_r unlink unlinkat @@ -67,6 +67,7 @@ GNULIB_FACCESSAT=0; AC_SUBST([GNULIB_FACCESSAT]) GNULIB_FCHDIR=0; AC_SUBST([GNULIB_FCHDIR]) GNULIB_FCHOWNAT=0; AC_SUBST([GNULIB_FCHOWNAT]) + GNULIB_FDATASYNC=0; AC_SUBST([GNULIB_FDATASYNC]) GNULIB_FSYNC=0; AC_SUBST([GNULIB_FSYNC]) GNULIB_FTRUNCATE=0; AC_SUBST([GNULIB_FTRUNCATE]) GNULIB_GETCWD=0; AC_SUBST([GNULIB_GETCWD]) @@ -110,6 +111,7 @@ HAVE_FACCESSAT=1; AC_SUBST([HAVE_FACCESSAT]) HAVE_FCHDIR=1; AC_SUBST([HAVE_FCHDIR]) HAVE_FCHOWNAT=1; AC_SUBST([HAVE_FCHOWNAT]) + HAVE_FDATASYNC=1; AC_SUBST([HAVE_FDATASYNC]) HAVE_FSYNC=1; AC_SUBST([HAVE_FSYNC]) HAVE_FTRUNCATE=1; AC_SUBST([HAVE_FTRUNCATE]) HAVE_GETDTABLESIZE=1; AC_SUBST([HAVE_GETDTABLESIZE])
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/modules/fdatasync Fri Sep 16 09:59:23 2011 -0600 @@ -0,0 +1,28 @@ +Description: +fdatasync(2) function: synchronize writes to a file. + +Files: +lib/fdatasync.c +m4/fdatasync.m4 + +Depends-on: +fsync +unistd + +configure.ac: +gl_FUNC_FDATASYNC +if test $HAVE_FDATASYNC = 0; then + AC_LIBOBJ([fdatasync]) +fi +gl_UNISTD_MODULE_INDICATOR([fdatasync]) + +Makefile.am: + +Include: +<unistd.h> + +License: +LGPLv2+ + +Maintainer: +Eric Blake
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/modules/fdatasync-tests Fri Sep 16 09:59:23 2011 -0600 @@ -0,0 +1,13 @@ +Files: +tests/test-fdatasync.c +tests/signature.h +tests/macros.h + +Depends-on: +errno + +configure.ac: + +Makefile.am: +TESTS += test-fdatasync +check_PROGRAMS += test-fdatasync
--- a/modules/fsync Fri Sep 16 10:28:13 2011 -0600 +++ b/modules/fsync Fri Sep 16 09:59:23 2011 -0600 @@ -1,5 +1,5 @@ Description: -fsync(2) function: synchronize writes to a file. +fsync(2) function: synchronize writes, including metadata, to a file. Files: lib/fsync.c
--- a/modules/unistd Fri Sep 16 10:28:13 2011 -0600 +++ b/modules/unistd Fri Sep 16 09:59:23 2011 -0600 @@ -39,6 +39,7 @@ -e 's/@''GNULIB_FACCESSAT''@/$(GNULIB_FACCESSAT)/g' \ -e 's/@''GNULIB_FCHDIR''@/$(GNULIB_FCHDIR)/g' \ -e 's/@''GNULIB_FCHOWNAT''@/$(GNULIB_FCHOWNAT)/g' \ + -e 's/@''GNULIB_FDATASYNC''@/$(GNULIB_FDATASYNC)/g' \ -e 's/@''GNULIB_FSYNC''@/$(GNULIB_FSYNC)/g' \ -e 's/@''GNULIB_FTRUNCATE''@/$(GNULIB_FTRUNCATE)/g' \ -e 's/@''GNULIB_GETCWD''@/$(GNULIB_GETCWD)/g' \ @@ -82,6 +83,7 @@ -e 's|@''HAVE_FACCESSAT''@|$(HAVE_FACCESSAT)|g' \ -e 's|@''HAVE_FCHDIR''@|$(HAVE_FCHDIR)|g' \ -e 's|@''HAVE_FCHOWNAT''@|$(HAVE_FCHOWNAT)|g' \ + -e 's|@''HAVE_FDATASYNC''@|$(HAVE_FDATASYNC)|g' \ -e 's|@''HAVE_FSYNC''@|$(HAVE_FSYNC)|g' \ -e 's|@''HAVE_FTRUNCATE''@|$(HAVE_FTRUNCATE)|g' \ -e 's|@''HAVE_GETDTABLESIZE''@|$(HAVE_GETDTABLESIZE)|g' \
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tests/test-fdatasync.c Fri Sep 16 09:59:23 2011 -0600 @@ -0,0 +1,64 @@ +/* Test of fdatasync() function. + Copyright (C) 2008-2011 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/>. */ + +#include <config.h> + +#include <unistd.h> + +#include "signature.h" +SIGNATURE_CHECK (fdatasync, int, (int)); + +#include <errno.h> +#include <fcntl.h> + +#include "macros.h" + +int +main (void) +{ + int fd; + const char *file = "test-fdatasync.txt"; + + if (fdatasync (STDOUT_FILENO) != 0) + { + ASSERT (errno == EINVAL /* POSIX */ + || errno == ENOTSUP /* seen on MacOS X 10.5 */ + || errno == EBADF /* seen on AIX 7.1 */ + ); + } + errno = 0; + ASSERT (fdatasync (-1) == -1); + ASSERT (errno == EBADF); + fd = open (file, O_WRONLY|O_CREAT|O_TRUNC, 0644); + ASSERT (0 <= fd); + ASSERT (write (fd, "hello", 5) == 5); + ASSERT (fdatasync (fd) == 0); + ASSERT (close (fd) == 0); +#if 0 + /* POSIX is self-contradictory on whether fdatasync must fail on + read-only file descriptors. Glibc allows it, as does our + implementation if fsync allows it. */ + fd = open (file, O_RDONLY); + ASSERT (0 <= fd); + errno = 0; + ASSERT (fdatasync (fd) == -1); + ASSERT (errno == EBADF); + ASSERT (close (fd) == 0); +#endif + ASSERT (unlink (file) == 0); + + return 0; +}