1 /* vi: set sw=4 ts=4: */
3 * Mini sync implementation for busybox
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
16 //config: sync is used to flush filesystem buffers.
17 //config:config FEATURE_SYNC_FANCY
18 //config: bool "Enable -d and -f flags (requires syncfs(2) in libc)"
20 //config: depends on SYNC
22 //config: sync -d FILE... executes fdatasync() on each FILE.
23 //config: sync -f FILE... executes syncfs() on each FILE.
25 //kbuild:lib-$(CONFIG_SYNC) += sync.o
26 //applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
28 //usage:#define sync_trivial_usage
29 //usage: ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...")
30 //usage:#define sync_full_usage "\n\n"
31 //usage: IF_NOT_FEATURE_SYNC_FANCY(
32 //usage: "Write all buffered blocks to disk"
34 //usage: IF_FEATURE_SYNC_FANCY(
35 //usage: "Write all buffered blocks (in FILEs) to disk"
36 //usage: "\n -d Avoid syncing metadata"
37 //usage: "\n -f Sync filesystems underlying FILEs"
42 /* This is a NOFORK applet. Be very careful! */
44 int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
45 int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
47 #if !ENABLE_FEATURE_SYNC_FANCY
48 /* coreutils-6.9 compat */
49 bb_warn_ignoring_args(argv[1]);
54 int ret = EXIT_SUCCESS;
57 OPT_DATASYNC = (1 << 0),
58 OPT_SYNCFS = (1 << 1),
61 opt_complementary = "d--f:f--d";
62 opts = getopt32(argv, "df");
65 /* Handle the no-argument case. */
70 int fd = open_or_warn(*argv, O_RDONLY);
76 if (opts & OPT_DATASYNC) {
81 if (opts & OPT_SYNCFS) {
83 * syncfs is documented to only fail with EBADF,
84 * which can't happen here. So, no error checks.
91 bb_simple_perror_msg(*argv);