1 /* vi: set sw=4 ts=4: */
2 /*
3 * Mini sync implementation for busybox
4 *
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10 //config:config SYNC
11 //config: bool "sync (3.8 kb)"
12 //config: default y
13 //config: help
14 //config: sync is used to flush filesystem buffers.
15 //config:config FEATURE_SYNC_FANCY
16 //config: bool "Enable -d and -f flags (requires syncfs(2) in libc)"
17 //config: default y
18 //config: depends on SYNC
19 //config: help
20 //config: sync -d FILE... executes fdatasync() on each FILE.
21 //config: sync -f FILE... executes syncfs() on each FILE.
22
23 // APPLET_NOFORK:name main location suid_type help
24 //applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
25
26 //kbuild:lib-$(CONFIG_SYNC) += sync.o
27
28 /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
29
30 //usage:#define sync_trivial_usage
31 //usage: ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...")
32 //usage:#define sync_full_usage "\n\n"
33 //usage: IF_NOT_FEATURE_SYNC_FANCY(
34 //usage: "Write all buffered blocks to disk"
35 //usage: )
36 //usage: IF_FEATURE_SYNC_FANCY(
37 //usage: "Write all buffered blocks (in FILEs) to disk"
38 //usage: "\n -d Avoid syncing metadata"
39 //usage: "\n -f Sync filesystems underlying FILEs"
40 //usage: )
41
42 #include "libbb.h"
43
44 /* This is a NOFORK applet. Be very careful! */
45
46 #if ENABLE_FEATURE_SYNC_FANCY || ENABLE_FSYNC
sync_common(int opts,char ** argv)47 static int sync_common(int opts, char **argv)
48 {
49 int ret;
50 enum {
51 OPT_DATASYNC = (1 << 0),
52 OPT_SYNCFS = (1 << 1),
53 };
54
55 ret = EXIT_SUCCESS;
56 do {
57 /* GNU "sync FILE" uses O_NONBLOCK open */
58 int fd = open_or_warn(*argv, /*O_NOATIME |*/ O_NOCTTY | O_RDONLY | O_NONBLOCK);
59 /* open(NOATIME) can only be used by owner or root, don't use NOATIME here */
60
61 if (fd < 0) {
62 ret = EXIT_FAILURE;
63 goto next;
64 }
65 # if ENABLE_FEATURE_SYNC_FANCY
66 if (opts & OPT_SYNCFS) {
67 /*
68 * syncfs is documented to only fail with EBADF,
69 * which can't happen here. So, no error checks.
70 */
71 syncfs(fd);
72 } else
73 # endif
74 if (((opts & OPT_DATASYNC) ? fdatasync(fd) : fsync(fd)) != 0) {
75 bb_simple_perror_msg(*argv);
76 ret = EXIT_FAILURE;
77 }
78 close(fd);
79 next:
80 argv++;
81 } while (*argv);
82
83 return ret;
84 }
85 #endif
86
87 #if ENABLE_SYNC
88 int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
sync_main(int argc UNUSED_PARAM,char ** argv IF_NOT_DESKTOP (UNUSED_PARAM))89 int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
90 {
91 # if !ENABLE_FEATURE_SYNC_FANCY
92 /* coreutils-6.9 compat */
93 bb_warn_ignoring_args(argv[1]);
94 sync();
95 return EXIT_SUCCESS;
96 # else
97 unsigned opts = getopt32(argv, "^" "df" "\0" "d--f:f--d");
98 argv += optind;
99 if (!argv[0]) {
100 sync();
101 return EXIT_SUCCESS;
102 }
103 return sync_common(opts, argv);
104 # endif
105 }
106 #endif
107
108 /*
109 * Mini fsync implementation for busybox
110 *
111 * Copyright (C) 2008 Nokia Corporation. All rights reserved.
112 *
113 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
114 */
115 //config:config FSYNC
116 //config: bool "fsync (3.6 kb)"
117 //config: default y
118 //config: help
119 //config: fsync is used to flush file-related cached blocks to disk.
120
121 // APPLET_NOFORK:name main location suid_type help
122 //applet:IF_FSYNC(APPLET_NOFORK(fsync, fsync, BB_DIR_BIN, BB_SUID_DROP, fsync))
123
124 //kbuild:lib-$(CONFIG_FSYNC) += sync.o
125
126 //usage:#define fsync_trivial_usage
127 //usage: "[-d] FILE..."
128 //usage:#define fsync_full_usage "\n\n"
129 //usage: "Write all buffered blocks in FILEs to disk\n"
130 //usage: "\n -d Avoid syncing metadata"
131
132 #if ENABLE_FSYNC
133 int fsync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
fsync_main(int argc UNUSED_PARAM,char ** argv)134 int fsync_main(int argc UNUSED_PARAM, char **argv)
135 {
136 int opts = getopt32(argv, "^" "d" "\0" "-1"/*min 1 arg*/);
137 argv += optind;
138 return sync_common(opts, argv);
139 }
140 #endif
141