tune2fs: new applet by Vladimir. Only supports -L LABEL

function                                             old     new   delta
tune2fs_main                                           -     165    +165
packed_usage                                       26692   26702     +10
applet_names                                        2148    2156      +8
applet_main                                         1264    1268      +4
applet_nameofs                                       632     634      +2
applet_install_loc                                   158     159      +1
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/0 up/down: 190/0)             Total: 190 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 72 insertions, 0 deletions

diff --git a/util-linux/Kbuild b/util-linux/Kbuild
index 7befe06..dc1d1f2 100644
--- a/util-linux/Kbuild
+++ b/util-linux/Kbuild
@@ -38,4 +38,5 @@ lib-$(CONFIG_SCRIPTREPLAY)      += scriptreplay.o
 lib-$(CONFIG_SETARCH)           += setarch.o
 lib-$(CONFIG_SWAPONOFF)         += swaponoff.o
 lib-$(CONFIG_SWITCH_ROOT)       += switch_root.o
+lib-$(CONFIG_MKFS_EXT2)         += tune2fs.o
 lib-$(CONFIG_UMOUNT)            += umount.o
diff --git a/util-linux/tune2fs.c b/util-linux/tune2fs.c
new file mode 100644
index 0000000..3b8f3d8
--- /dev/null
+++ b/util-linux/tune2fs.c
@@ -0,0 +1,71 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * tune2fs: utility to modify EXT2 filesystem
+ *
+ * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+#include <linux/fs.h>
+#include <linux/ext2_fs.h>
+#include "volume_id/volume_id_internal.h"
+
+// storage helpers
+char BUG_wrong_field_size(void);
+#define STORE_LE(field, value) \
+do { \
+	if (sizeof(field) == 4) \
+		field = cpu_to_le32(value); \
+	else if (sizeof(field) == 2) \
+		field = cpu_to_le16(value); \
+	else if (sizeof(field) == 1) \
+		field = (value); \
+	else \
+		BUG_wrong_field_size(); \
+} while (0)
+
+#define FETCH_LE32(field) \
+	(sizeof(field) == 4 ? cpu_to_le32(field) : BUG_wrong_field_size())
+
+enum {
+	OPT_L = 1 << 0,	// label
+};
+
+int tune2fs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int tune2fs_main(int argc UNUSED_PARAM, char **argv)
+{
+	unsigned opts;
+	const char *label;
+	struct ext2_super_block *sb;
+	int fd;
+
+	opt_complementary = "=1";
+	opts = getopt32(argv, "L:", &label);
+	argv += optind; // argv[0] -- device
+
+	if (!opts)
+		bb_show_usage();
+
+	// read superblock
+	fd = xopen(argv[0], O_RDWR);
+	xlseek(fd, 1024, SEEK_SET);
+	sb = xzalloc(1024);
+	xread(fd, sb, 1024);
+
+	// mangle superblock
+	//STORE_LE(sb->s_wtime, time(NULL)); - why bother?
+	// set the label
+	if (1 /*opts & OPT_L*/)
+		safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
+	// write superblock
+	xlseek(fd, 1024, SEEK_SET);
+	xwrite(fd, sb, 1024);
+
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		free(sb);
+	}
+
+	xclose(fd);
+	return EXIT_SUCCESS;
+}