[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini sync implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
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[3621] | 6 | * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
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[821] | 7 | *
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[2725] | 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 9 | */
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| 10 |
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| 11 | /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
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[3621] | 12 | //config:config SYNC
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| 13 | //config: bool "sync"
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| 14 | //config: default y
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| 15 | //config: help
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| 16 | //config: sync is used to flush filesystem buffers.
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| 17 | //config:config FEATURE_SYNC_FANCY
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| 18 | //config: bool "Enable -d and -f flags (requres syncfs(2) in libc)"
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| 19 | //config: default y
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| 20 | //config: depends on SYNC
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| 21 | //config: help
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| 22 | //config: sync -d FILE... executes fdatasync() on each FILE.
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| 23 | //config: sync -f FILE... executes syncfs() on each FILE.
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[821] | 24 |
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[3621] | 25 | //kbuild:lib-$(CONFIG_SYNC) += sync.o
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| 26 | //applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
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| 27 |
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[3232] | 28 | //usage:#define sync_trivial_usage
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[3621] | 29 | //usage: ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...")
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[3232] | 30 | //usage:#define sync_full_usage "\n\n"
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[3621] | 31 | //usage: IF_NOT_FEATURE_SYNC_FANCY(
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[3232] | 32 | //usage: "Write all buffered blocks to disk"
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[3621] | 33 | //usage: )
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| 34 | //usage: IF_FEATURE_SYNC_FANCY(
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| 35 | //usage: "Write all buffered blocks (in FILEs) to disk"
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| 36 | //usage: "\n -d Avoid syncing metadata"
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| 37 | //usage: "\n -f Sync filesystems underlying FILEs"
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| 38 | //usage: )
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[3232] | 39 |
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[1765] | 40 | #include "libbb.h"
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[821] | 41 |
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[1765] | 42 | /* This is a NOFORK applet. Be very careful! */
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| 43 |
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[2725] | 44 | int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 45 | int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
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[821] | 46 | {
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[3621] | 47 | #if !ENABLE_FEATURE_SYNC_FANCY
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[2725] | 48 | /* coreutils-6.9 compat */
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| 49 | bb_warn_ignoring_args(argv[1]);
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[821] | 50 | sync();
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[3621] | 51 | return EXIT_SUCCESS;
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| 52 | #else
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| 53 | unsigned opts;
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| 54 | int ret = EXIT_SUCCESS;
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[821] | 55 |
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[3621] | 56 | enum {
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| 57 | OPT_DATASYNC = (1 << 0),
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| 58 | OPT_SYNCFS = (1 << 1),
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| 59 | };
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| 60 |
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| 61 | opt_complementary = "d--f:f--d";
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| 62 | opts = getopt32(argv, "df");
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| 63 | argv += optind;
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| 64 |
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| 65 | /* Handle the no-argument case. */
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| 66 | if (!argv[0])
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| 67 | sync();
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| 68 |
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| 69 | while (*argv) {
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| 70 | int fd = open_or_warn(*argv, O_RDONLY);
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| 71 |
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| 72 | if (fd < 0) {
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| 73 | ret = EXIT_FAILURE;
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| 74 | goto next;
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| 75 | }
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| 76 | if (opts & OPT_DATASYNC) {
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| 77 | if (fdatasync(fd))
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| 78 | goto err;
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| 79 | goto do_close;
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| 80 | }
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| 81 | if (opts & OPT_SYNCFS) {
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| 82 | /*
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| 83 | * syncfs is documented to only fail with EBADF,
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| 84 | * which can't happen here. So, no error checks.
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| 85 | */
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| 86 | syncfs(fd);
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| 87 | goto do_close;
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| 88 | }
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| 89 | if (fsync(fd)) {
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| 90 | err:
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| 91 | bb_simple_perror_msg(*argv);
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| 92 | ret = EXIT_FAILURE;
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| 93 | }
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| 94 | do_close:
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| 95 | close(fd);
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| 96 | next:
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| 97 | ++argv;
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| 98 | }
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| 99 |
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| 100 | return ret;
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| 101 | #endif
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[821] | 102 | }
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