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/* vi: set sw=4 ts=4: */
/*
* Mini sync implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config SYNC
//config: bool "sync (769 bytes)"
//config: default y
//config: help
//config: sync is used to flush filesystem buffers.
//config:config FEATURE_SYNC_FANCY
//config: bool "Enable -d and -f flags (requires syncfs(2) in libc)"
//config: default y
//config: depends on SYNC
//config: help
//config: sync -d FILE... executes fdatasync() on each FILE.
//config: sync -f FILE... executes syncfs() on each FILE.
//applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
//kbuild:lib-$(CONFIG_SYNC) += sync.o
/* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
//usage:#define sync_trivial_usage
//usage: ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...")
//usage:#define sync_full_usage "\n\n"
//usage: IF_NOT_FEATURE_SYNC_FANCY(
//usage: "Write all buffered blocks to disk"
//usage: )
//usage: IF_FEATURE_SYNC_FANCY(
//usage: "Write all buffered blocks (in FILEs) to disk"
//usage: "\n -d Avoid syncing metadata"
//usage: "\n -f Sync filesystems underlying FILEs"
//usage: )
#include "libbb.h"
/* This is a NOFORK applet. Be very careful! */
int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
{
#if !ENABLE_FEATURE_SYNC_FANCY
/* coreutils-6.9 compat */
bb_warn_ignoring_args(argv[1]);
sync();
return EXIT_SUCCESS;
#else
unsigned opts;
int ret = EXIT_SUCCESS;
enum {
OPT_DATASYNC = (1 << 0),
OPT_SYNCFS = (1 << 1),
};
opt_complementary = "d--f:f--d";
opts = getopt32(argv, "df");
argv += optind;
/* Handle the no-argument case. */
if (!argv[0])
sync();
while (*argv) {
int fd = open_or_warn(*argv, O_RDONLY);
if (fd < 0) {
ret = EXIT_FAILURE;
goto next;
}
if (opts & OPT_DATASYNC) {
if (fdatasync(fd))
goto err;
goto do_close;
}
if (opts & OPT_SYNCFS) {
/*
* syncfs is documented to only fail with EBADF,
* which can't happen here. So, no error checks.
*/
syncfs(fd);
goto do_close;
}
if (fsync(fd)) {
err:
bb_simple_perror_msg(*argv);
ret = EXIT_FAILURE;
}
do_close:
close(fd);
next:
++argv;
}
return ret;
#endif
}
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