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-rw-r--r--coreutils/sync.c78
1 files changed, 75 insertions, 3 deletions
diff --git a/coreutils/sync.c b/coreutils/sync.c
index 7d98a1e..974e904 100644
--- a/coreutils/sync.c
+++ b/coreutils/sync.c
@@ -3,16 +3,39 @@
* 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.
*/
/* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
+//config:config SYNC
+//config: bool "sync"
+//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 (requres 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.
+
+//kbuild:lib-$(CONFIG_SYNC) += sync.o
+//applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
//usage:#define sync_trivial_usage
-//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"
@@ -21,10 +44,59 @@
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
}