File synchronization fixes.

* admin/CPP-DEFINES (BSD_SYSTEM, HAVE_FSYNC): Remove.
* admin/merge-gnulib (GNULIB_MODULES): Add fsync, fdatasync.
* configure.ac (BSD_SYSTEM, BSD_SYSTEM_AHB): Remove; no longer needed.
(fsync): Remove check; now done by gnulib.
* lib/fdatasync.c, lib/fsync.c, m4/fdatasync.m4, m4/fsync.m4:
New files, from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib-src/Makefile.in (LIB_FDATASYNC): New macro.
(emacsclient${EXEEXT}): Use it.
* lib-src/emacsclient.c (main): Use fdatasync, not fsync, since we don't
care about metadata.  Keep trying if interrupted.
* lib-src/movemail.c (main, popmail): Don't worry about BSD_SYSTEM, since
fsync is available everywhere (or there is a substitute).  Don't
report an error if fsync returns EINVAL.
* nt/inc/ms-w32.h (fdatasync): New macro, suggested by Eli Zaretskii.
* src/Makefile.in (LIB_FDATASYNC): New macro.
(LIBES): Use it.
* src/conf_post.h (BSD_SYSTEM, BSD_SYSTEM_AHB): Remove; no longer needed.
* src/fileio.c (Fwrite_region, write_region_inhibit_fsync):
Don't worry about HAVE_FSYNC, since a substitute fsync is
available if the system lacks one.
(Fwrite_regin): Retry fsync if interrupted.

Fixes: debbugs:13944

3 files changed, 129 insertions, 1 deletions

diff --git a/lib/fdatasync.c b/lib/fdatasync.c
new file mode 100644
index 00000000000..8f9bf15a527
--- /dev/null
+++ b/lib/fdatasync.c
@@ -0,0 +1,27 @@
+/* Emulate fdatasync on platforms that lack it.
+
+   Copyright (C) 2011-2013 Free Software Foundation, Inc.
+
+   This library 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 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
+   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)
+{
+  /* This does more work than strictly necessary, but is the best we
+     can do portably.  */
+  return fsync (fd);
+}
diff --git a/lib/fsync.c b/lib/fsync.c
new file mode 100644
index 00000000000..8a1a975049e
--- /dev/null
+++ b/lib/fsync.c
@@ -0,0 +1,83 @@
+/* Emulate fsync on platforms that lack it, primarily Windows and
+   cross-compilers like MinGW.
+
+   This is derived from sqlite3 sources.
+   http://www.sqlite.org/cvstrac/rlog?f=sqlite/src/os_win.c
+   http://www.sqlite.org/copyright.html
+
+   Written by Richard W.M. Jones <rjones.at.redhat.com>
+
+   Copyright (C) 2008-2013 Free Software Foundation, Inc.
+
+   This library 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 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
+   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>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
+/* FlushFileBuffers */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+
+# include <errno.h>
+
+/* Get _get_osfhandle.  */
+# include "msvc-nothrow.h"
+
+int
+fsync (int fd)
+{
+  HANDLE h = (HANDLE) _get_osfhandle (fd);
+  DWORD err;
+
+  if (h == INVALID_HANDLE_VALUE)
+    {
+      errno = EBADF;
+      return -1;
+    }
+
+  if (!FlushFileBuffers (h))
+    {
+      /* Translate some Windows errors into rough approximations of Unix
+       * errors.  MSDN is useless as usual - in this case it doesn't
+       * document the full range of errors.
+       */
+      err = GetLastError ();
+      switch (err)
+        {
+        case ERROR_ACCESS_DENIED:
+          /* For a read-only handle, fsync should succeed, even though we have
+             no way to sync the access-time changes.  */
+          return 0;
+
+          /* eg. Trying to fsync a tty. */
+        case ERROR_INVALID_HANDLE:
+          errno = EINVAL;
+          break;
+
+        default:
+          errno = EIO;
+        }
+      return -1;
+    }
+
+  return 0;
+}
+
+#else /* !Windows */
+
+# error "This platform lacks fsync function, and Gnulib doesn't provide a replacement. This is a bug in Gnulib."
+
+#endif /* !Windows */
diff --git a/lib/gnulib.mk b/lib/gnulib.mk
index c130cbc65b8..4b754ec21dd 100644
--- a/lib/gnulib.mk
+++ b/lib/gnulib.mk
@@ -21,7 +21,7 @@
 # the same distribution terms as the rest of that program.
 #
 # Generated by gnulib-tool.
-# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=dup --avoid=errno --avoid=fchdir --avoid=fcntl --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=sys_types --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt c-ctype c-strcase careadlinkat close-stream crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl-h fdopendir filemode fstatat getloadavg getopt-gnu gettime gettimeofday ignore-value intprops largefile lstat manywarnings memrchr mktime pselect pthread_sigmask putenv readlink readlinkat sig2str socklen stat-time stdalign stdarg stdbool stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv utimens warnings
+# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=dup --avoid=errno --avoid=fchdir --avoid=fcntl --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=sys_types --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt c-ctype c-strcase careadlinkat close-stream crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday ignore-value intprops largefile lstat manywarnings memrchr mktime pselect pthread_sigmask putenv readlink readlinkat sig2str socklen stat-time stdalign stdarg stdbool stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv utimens warnings
 
 
 MOSTLYCLEANFILES += core *.stackdump
@@ -297,6 +297,15 @@ EXTRA_DIST += fcntl.in.h
 
 ## end   gnulib module fcntl-h
 
+## begin gnulib module fdatasync
+
+
+EXTRA_DIST += fdatasync.c
+
+EXTRA_libgnu_a_SOURCES += fdatasync.c
+
+## end   gnulib module fdatasync
+
 ## begin gnulib module fdopendir
 
 
@@ -332,6 +341,15 @@ EXTRA_libgnu_a_SOURCES += at-func.c fstatat.c
 
 ## end   gnulib module fstatat
 
+## begin gnulib module fsync
+
+
+EXTRA_DIST += fsync.c
+
+EXTRA_libgnu_a_SOURCES += fsync.c
+
+## end   gnulib module fsync
+
 ## begin gnulib module getgroups
 
 if gl_GNULIB_ENABLED_getgroups