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/* sync - update the super block
Copyright (C) 1994-2022 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 <https://www.gnu.org/licenses/>. */
/* Written by Jim Meyering */
#include <config.h>
#include <assert.h>
#include <getopt.h>
#include <stdio.h>
#include <sys/types.h>
#include "system.h"
#include "die.h"
#include "error.h"
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "sync"
#define AUTHORS \
proper_name ("Jim Meyering"), \
proper_name ("Giuseppe Scrivano")
#ifndef HAVE_SYNCFS
# define HAVE_SYNCFS 0
#endif
enum sync_mode
{
MODE_FILE,
MODE_DATA,
MODE_FILE_SYSTEM,
MODE_SYNC
};
static struct option const long_options[] =
{
{"data", no_argument, NULL, 'd'},
{"file-system", no_argument, NULL, 'f'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("Usage: %s [OPTION] [FILE]...\n"), program_name);
fputs (_("\
Synchronize cached writes to persistent storage\n\
\n\
If one or more files are specified, sync only them,\n\
or their containing file systems.\n\
\n\
"), stdout);
fputs (_("\
-d, --data sync only file data, no unneeded metadata\n\
"), stdout);
fputs (_("\
-f, --file-system sync the file systems that contain the files\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_ancillary_info (PROGRAM_NAME);
}
exit (status);
}
/* Sync the specified FILE, or file systems associated with FILE.
Return 1 on success. */
static bool
sync_arg (enum sync_mode mode, char const *file)
{
bool ret = true;
int open_flags = O_RDONLY | O_NONBLOCK;
int fd;
#if defined _AIX || defined __CYGWIN__
/* AIX 7.1, CYGWIN 2.9.0, fsync requires write access to file. */
if (mode == MODE_FILE)
open_flags = O_WRONLY | O_NONBLOCK;
#endif
/* Note O_PATH might be supported with syncfs(),
though as of Linux 3.18 is not. */
fd = open (file, open_flags);
if (fd < 0)
{
/* Use the O_RDONLY errno, which is significant
with directories for example. */
int rd_errno = errno;
if (open_flags != (O_WRONLY | O_NONBLOCK))
fd = open (file, O_WRONLY | O_NONBLOCK);
if (fd < 0)
{
error (0, rd_errno, _("error opening %s"), quoteaf (file));
return false;
}
}
/* We used O_NONBLOCK above to not hang with fifos,
so reset that here. */
int fdflags = fcntl (fd, F_GETFL);
if (fdflags == -1
|| fcntl (fd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
{
error (0, errno, _("couldn't reset non-blocking mode %s"),
quoteaf (file));
ret = false;
}
if (ret == true)
{
int sync_status = -1;
switch (mode)
{
case MODE_DATA:
sync_status = fdatasync (fd);
break;
case MODE_FILE:
sync_status = fsync (fd);
break;
#if HAVE_SYNCFS
case MODE_FILE_SYSTEM:
sync_status = syncfs (fd);
break;
#endif
default:
assert ("invalid sync_mode");
}
if (sync_status < 0)
{
error (0, errno, _("error syncing %s"), quoteaf (file));
ret = false;
}
}
if (close (fd) < 0)
{
error (0, errno, _("failed to close %s"), quoteaf (file));
ret = false;
}
return ret;
}
int
main (int argc, char **argv)
{
int c;
bool args_specified;
bool arg_data = false, arg_file_system = false;
enum sync_mode mode;
bool ok = true;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
atexit (close_stdout);
while ((c = getopt_long (argc, argv, "df", long_options, NULL))
!= -1)
{
switch (c)
{
case 'd':
arg_data = true;
break;
case 'f':
arg_file_system = true;
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (EXIT_FAILURE);
}
}
args_specified = optind < argc;
if (arg_data && arg_file_system)
{
die (EXIT_FAILURE, 0,
_("cannot specify both --data and --file-system"));
}
if (!args_specified && arg_data)
die (EXIT_FAILURE, 0, _("--data needs at least one argument"));
if (! args_specified || (arg_file_system && ! HAVE_SYNCFS))
mode = MODE_SYNC;
else if (arg_file_system)
mode = MODE_FILE_SYSTEM;
else if (! arg_data)
mode = MODE_FILE;
else
mode = MODE_DATA;
if (mode == MODE_SYNC)
sync ();
else
{
for (; optind < argc; optind++)
ok &= sync_arg (mode, argv[optind]);
}
return ok ? EXIT_SUCCESS : EXIT_FAILURE;
}
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