fsync: new applet by Pekka Pessi (Pekka.Pessi AT nokia.com)

function                                             old     new   delta
fsync_main                                             -     128    +128
fdatasync                                              -      39     +39
packed_usage                                       26596   26622     +26
applet_names                                        2098    2104      +6
applet_main                                         1240    1244      +4
applet_nameofs                                       620     622      +2
applet_install_loc                                   155     156      +1
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 5/0 up/down: 206/0)             Total: 206 bytes

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 48 insertions, 0 deletions

diff --git a/coreutils/Config.in b/coreutils/Config.in
index b047ce5e2..88642d71e 100644
--- a/coreutils/Config.in
+++ b/coreutils/Config.in
@@ -249,6 +249,12 @@ config FOLD
 	help
 	  Wrap text to fit a specific width.
 
+config FSYNC
+	bool "fsync"
+	default n
+	help
+	  fsync is used to flush file-related cached blocks to disk.
+
 config HEAD
 	bool "head"
 	default n
diff --git a/coreutils/Kbuild b/coreutils/Kbuild
index 57100a9cf..4d6bde7b9 100644
--- a/coreutils/Kbuild
+++ b/coreutils/Kbuild
@@ -36,6 +36,7 @@ lib-$(CONFIG_EXPR)      += expr.o
 lib-$(CONFIG_EXPAND)    += expand.o
 lib-$(CONFIG_FALSE)     += false.o
 lib-$(CONFIG_FOLD)      += fold.o
+lib-$(CONFIG_FSYNC)     += fsync.o
 lib-$(CONFIG_HEAD)      += head.o
 lib-$(CONFIG_HOSTID)    += hostid.o
 lib-$(CONFIG_ID)        += id.o
diff --git a/coreutils/fsync.c b/coreutils/fsync.c
new file mode 100644
index 000000000..f00803c5b
--- /dev/null
+++ b/coreutils/fsync.c
@@ -0,0 +1,41 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini fsync implementation for busybox
+ *
+ * Copyright (C) 2008 Nokia Corporation. All rights reserved.
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+
+/* This is a NOFORK applet. Be very careful! */
+
+int fsync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int fsync_main(int argc UNUSED_PARAM, char **argv)
+{
+	int status;
+	int opts;
+
+	opts = getopt32(argv, "d"); /* fdatasync */
+	argv += optind;
+	if (!*argv) {
+		bb_show_usage();
+	}
+
+	status = EXIT_SUCCESS;
+	do {
+		int fd = open3_or_warn(*argv, O_NOATIME | O_NOCTTY | O_RDONLY, 0);
+
+		if (fd == -1) {
+			status = EXIT_FAILURE;
+			continue;
+		}
+		if ((opts ? fdatasync(fd) : fsync(fd))) {
+			//status = EXIT_FAILURE; - do we want this?
+			bb_simple_perror_msg(*argv);
+		}
+		close(fd);
+	} while (*++argv);
+
+	return status;
+}