/* * 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; }