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 47static 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 88int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 89int 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 133int fsync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 134int 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