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/*
* blockdev implementation for busybox
*
* Copyright (C) 2010 Sergey Naumov <sknaumov@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//applet:IF_BLOCKDEV(APPLET(blockdev, BB_DIR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_BLOCKDEV) += blockdev.o
//config:config BLOCKDEV
//config: bool "blockdev"
//config: default y
//config: help
//config: Performs some ioctls with block devices.
//usage:#define blockdev_trivial_usage
//usage: "OPTION BLOCKDEV"
//usage:#define blockdev_full_usage "\n\n"
//usage: "Options:"
//usage: "\n --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 --getsize Get device size in 512-byte sectors"
//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,
};
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 = 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, char **argv)
{
const struct bdc *bdcmd;
int fd;
uint64_t u64;
union {
int i;
unsigned long lu;
uint64_t u64;
} ioctl_val_on_stack;
if ((unsigned)(argc - 3) > 1) /* must have 2 or 3 args */
bb_show_usage();
bdcmd = find_cmd(*++argv);
u64 = (int)bdcmd->argval;
if (bdcmd->flags & FL_USRARG)
u64 = xatoi_positive(*++argv);
if (!*++argv || argv[1])
bb_show_usage();
fd = xopen(*argv, 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;
/* 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;
}
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