path: root/e2fsprogs/tune2fs.c (plain)
blob: 0485e82ce5e08b29fb1eb00bc65c73e557200cc8

1	/* vi: set sw=4 ts=4: */
2	/*
3	* tune2fs: utility to modify EXT2 filesystem
4	*
5	* Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
6	*
7	* Licensed under GPLv2, see file LICENSE in this source tree.
8	*/
9	//config:config TUNE2FS
10	//config: bool "tune2fs"
11	//config: default n # off: it is too limited compared to upstream version
12	//config: help
13	//config: tune2fs allows the system administrator to adjust various tunable
14	//config: filesystem parameters on Linux ext2/ext3 filesystems.
15
16	//applet:IF_TUNE2FS(APPLET(tune2fs, BB_DIR_SBIN, BB_SUID_DROP))
17
18	//TODO alias to "tune2fs -L LABEL": //applet:IF_E2LABEL(APPLET_ODDNAME(e2label, tune2fs, BB_DIR_SBIN, BB_SUID_DROP, e2label))
19
20	//kbuild:lib-$(CONFIG_TUNE2FS) += tune2fs.o
21
22	//usage:#define tune2fs_trivial_usage
23	//usage: "[-c MAX_MOUNT_COUNT] "
24	////usage: "[-e errors-behavior] [-g group] "
25	//usage: "[-i DAYS] "
26	////usage: "[-j] [-J journal-options] [-l] [-s sparse-flag] "
27	////usage: "[-m reserved-blocks-percent] [-o [^]mount-options[,...]] "
28	////usage: "[-r reserved-blocks-count] [-u user] "
29	//usage: "[-C MOUNT_COUNT] "
30	//usage: "[-L LABEL] "
31	////usage: "[-M last-mounted-dir] [-O [^]feature[,...]] "
32	////usage: "[-T last-check-time] [-U UUID] "
33	//usage: "BLOCKDEV"
34	//usage:
35	//usage:#define tune2fs_full_usage "\n\n"
36	//usage: "Adjust filesystem options on ext[23] filesystems"
37
38	#include "libbb.h"
39	#include <linux/fs.h>
40	#include "bb_e2fs_defs.h"
41
42	// storage helpers
43	char BUG_wrong_field_size(void);
44	#define STORE_LE(field, value) \
45	do { \
46	if (sizeof(field) == 4) \
47	field = SWAP_LE32(value); \
48	else if (sizeof(field) == 2) \
49	field = SWAP_LE16(value); \
50	else if (sizeof(field) == 1) \
51	field = (value); \
52	else \
53	BUG_wrong_field_size(); \
54	} while (0)
55
56	#define FETCH_LE32(field) \
57	(sizeof(field) == 4 ? SWAP_LE32(field) : BUG_wrong_field_size())
58
59	enum {
60	OPT_L = 1 << 0, // label
61	OPT_c = 1 << 1, // max mount count
62	OPT_i = 1 << 2, // check interval
63	OPT_C = 1 << 3, // current mount count
64	};
65
66	int tune2fs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
67	int tune2fs_main(int argc UNUSED_PARAM, char **argv)
68	{
69	unsigned opts;
70	const char *label, *str_c, *str_i, *str_C;
71	struct ext2_super_block *sb;
72	int fd;
73
74	opt_complementary = "=1";
75	opts = getopt32(argv, "L:c:i:C:", &label, &str_c, &str_i, &str_C);
76	if (!opts)
77	bb_show_usage();
78	argv += optind; // argv[0] -- device
79
80	// read superblock
81	fd = xopen(argv[0], O_RDWR);
82	xlseek(fd, 1024, SEEK_SET);
83	sb = xzalloc(1024);
84	xread(fd, sb, 1024);
85
86	// mangle superblock
87	//STORE_LE(sb->s_wtime, time(NULL)); - why bother?
88
89	if (opts & OPT_C) {
90	int n = xatoi_range(str_C, 1, 0xfffe);
91	if (n == 0) n = 1;
92	STORE_LE(sb->s_mnt_count, (unsigned)n);
93	}
94
95	// set the label
96	if (opts & OPT_L)
97	safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
98
99	if (opts & OPT_c) {
100	int n = xatoi_range(str_c, -1, 0xfffe);
101	if (n == 0)
102	n = -1;
103	STORE_LE(sb->s_max_mnt_count, (unsigned)n);
104	}
105
106	if (opts & OPT_i) {
107	unsigned n = xatou_range(str_i, 0, (unsigned)0xffffffff / (24*60*60)) * 24*60*60;
108	STORE_LE(sb->s_checkinterval, n);
109	}
110
111	// write superblock
112	xlseek(fd, 1024, SEEK_SET);
113	xwrite(fd, sb, 1024);
114
115	if (ENABLE_FEATURE_CLEAN_UP) {
116	free(sb);
117	}
118
119	xclose(fd);
120	return EXIT_SUCCESS;
121	}
122