aboutsummaryrefslogtreecommitdiff
path: root/util-linux/blockdev.c
blob: 5d8e465b46fbebf35e8a4c4c8cdf4ac942846269 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/*
 * blockdev implementation for busybox
 *
 * Copyright (C) 2010 Sergey Naumov <sknaumov@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//config:config BLOCKDEV
//config:	bool "blockdev (2.3 kb)"
//config:	default y
//config:	help
//config:	Performs some ioctls with block devices.

//applet:IF_BLOCKDEV(APPLET_NOEXEC(blockdev, blockdev, BB_DIR_SBIN, BB_SUID_DROP, blockdev))

//kbuild:lib-$(CONFIG_BLOCKDEV) += blockdev.o

//usage:#define blockdev_trivial_usage
//usage:	"OPTION BLOCKDEV"
//usage:#define blockdev_full_usage "\n\n"
//usage:       "	--setro		Set ro"
//usage:     "\n	--setrw		Set rw"
//usage:     "\n	--getro		Get ro"
//usage:     "\n	--getss		Get sector size"
//usage:     "\n	--getbsz	Get block size"
//usage:     "\n	--setbsz BYTES	Set block size"
//usage:     "\n	--getsz		Get device size in 512-byte sectors"
/*//usage:     "\n	--getsize	Get device size in sectors (deprecated)"*/
//usage:     "\n	--getsize64	Get device size in bytes"
//usage:     "\n	--flushbufs	Flush buffers"
//usage:     "\n	--rereadpt	Reread partition table"


#include "libbb.h"
#include <linux/fs.h>

enum {
	ARG_NONE   = 0,
	ARG_INT    = 1,
	ARG_ULONG  = 2,
	/* Yes, BLKGETSIZE64 takes pointer to uint64_t, not ullong! */
	ARG_U64    = 3,
	ARG_MASK   = 3,

	FL_USRARG   = 4, /* argument is provided by user */
	FL_NORESULT = 8,
	FL_SCALE512 = 16,
};

struct bdc {
	uint32_t   ioc;                       /* ioctl code */
	const char name[sizeof("flushbufs")]; /* "--setfoo" wothout "--" */
	uint8_t    flags;
	int8_t     argval;                    /* default argument value */
};

static const struct bdc bdcommands[] = {
	{
		.ioc = BLKROSET,
		.name = "setro",
		.flags = ARG_INT + FL_NORESULT,
		.argval = 1,
	},{
		.ioc = BLKROSET,
		.name = "setrw",
		.flags = ARG_INT + FL_NORESULT,
		.argval = 0,
	},{
		.ioc = BLKROGET,
		.name = "getro",
		.flags = ARG_INT,
		.argval = -1,
	},{
		.ioc = BLKSSZGET,
		.name = "getss",
		.flags = ARG_INT,
		.argval = -1,
	},{
		.ioc = BLKBSZGET,
		.name = "getbsz",
		.flags = ARG_INT,
		.argval = -1,
	},{
		.ioc = BLKBSZSET,
		.name = "setbsz",
		.flags = ARG_INT + FL_NORESULT + FL_USRARG,
		.argval = 0,
	},{
		.ioc = BLKGETSIZE64,
		.name = "getsz",
		.flags = ARG_U64 + FL_SCALE512,
		.argval = -1,
	},{
		.ioc = BLKGETSIZE,
		.name = "getsize",
		.flags = ARG_ULONG,
		.argval = -1,
	},{
		.ioc = BLKGETSIZE64,
		.name = "getsize64",
		.flags = ARG_U64,
		.argval = -1,
	},{
		.ioc = BLKFLSBUF,
		.name = "flushbufs",
		.flags = ARG_NONE + FL_NORESULT,
		.argval = 0,
	},{
		.ioc = BLKRRPART,
		.name = "rereadpt",
		.flags = ARG_NONE + FL_NORESULT,
		.argval = 0,
	}
};

static const struct bdc *find_cmd(const char *s)
{
	const struct bdc *bdcmd = bdcommands;
	if (s[0] == '-' && s[1] == '-') {
		s += 2;
		do {
			if (strcmp(s, bdcmd->name) == 0)
				return bdcmd;
			bdcmd++;
		} while (bdcmd != bdcommands + ARRAY_SIZE(bdcommands));
	}
	bb_show_usage();
}

int blockdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int blockdev_main(int argc UNUSED_PARAM, char **argv)
{
	const struct bdc *bdcmd;
	int fd;
	uint64_t u64;
	union {
		int i;
		unsigned long lu;
		uint64_t u64;
	} ioctl_val_on_stack;

	argv++;
	if (!argv[0] || !argv[1]) /* must have at least 2 args */
		bb_show_usage();

	bdcmd = find_cmd(*argv);

	u64 = (int)bdcmd->argval;
	if (bdcmd->flags & FL_USRARG)
		u64 = xatoi_positive(*++argv);

	argv++;
	if (!argv[0] || argv[1])
		bb_show_usage();
	fd = xopen(argv[0], O_RDONLY);

	ioctl_val_on_stack.u64 = u64;
#if BB_BIG_ENDIAN
	/* Store data properly wrt data size.
	 * (1) It's no-op for little-endian.
	 * (2) it's no-op for 0 and -1. Only --setro uses arg != 0 and != -1,
	 * and it is ARG_INT. --setbsz USER_VAL is also ARG_INT.
	 * Thus, we don't need to handle ARG_ULONG.
	 */
	switch (bdcmd->flags & ARG_MASK) {
	case ARG_INT:
		ioctl_val_on_stack.i = (int)u64;
		break;
# if 0 /* unused */
	case ARG_ULONG:
		ioctl_val_on_stack.lu = (unsigned long)u64;
		break;
# endif
	}
#endif

	if (ioctl(fd, bdcmd->ioc, &ioctl_val_on_stack.u64) == -1)
		bb_simple_perror_msg_and_die(*argv);

	/* Fetch it into register(s) */
	u64 = ioctl_val_on_stack.u64;

	if (bdcmd->flags & FL_SCALE512)
		u64 >>= 9;

	/* Zero- or one-extend the value if needed, then print */
	switch (bdcmd->flags & (ARG_MASK+FL_NORESULT)) {
	case ARG_INT:
		/* Smaller code when we use long long
		 * (gcc tail-merges printf call)
		 */
		printf("%lld\n", (long long)(int)u64);
		break;
	case ARG_ULONG:
		u64 = (unsigned long)u64;
		/* FALLTHROUGH */
	case ARG_U64:
		printf("%llu\n", (unsigned long long)u64);
		break;
	}

	if (ENABLE_FEATURE_CLEAN_UP)
		close(fd);
	return EXIT_SUCCESS;
}