util-linux/blockdev.c

   1 /*
   2  * blockdev implementation for busybox
   3  *
   4  * Copyright (C) 2010 Sergey Naumov <sknaumov@gmail.com>
   5  *
   6  * Licensed under GPLv2, see file License in this tarball for details.
   7  */
   8
   9 //applet:IF_BLOCKDEV(APPLET(blockdev, _BB_DIR_SBIN, _BB_SUID_DROP))
  10
  11 //kbuild:lib-$(CONFIG_BLOCKDEV) += blockdev.o
  12
  13 //config:config BLOCKDEV
  14 //config:       bool "blockdev"
  15 //config:       default y
  16 //config:       help
  17 //config:         Performs some ioctls with block devices.
  18
  19 //usage:#define blockdev_trivial_usage
  20 //usage:        "OPTION BLOCKDEV"
  21 //usage:#define blockdev_full_usage "\n\n"
  22 //usage:       "Options:"
  23 //usage:     "\n        --setro         Set ro"
  24 //usage:     "\n        --setrw         Set rw"
  25 //usage:     "\n        --getro         Get ro"
  26 //usage:     "\n        --getss         Get sector size"
  27 //usage:     "\n        --getbsz        Get block size"
  28 //usage:     "\n        --setbsz BYTES  Set block size"
  29 //usage:     "\n        --getsize       Get device size in 512-byte sectors"
  30 //usage:     "\n        --getsize64     Get device size in bytes"
  31 //usage:     "\n        --flushbufs     Flush buffers"
  32 //usage:     "\n        --rereadpt      Reread partition table"
  33
  34
  35 #include "libbb.h"
  36 #include <linux/fs.h>
  37
  38 enum {
  39         ARG_NONE   = 0,
  40         ARG_INT    = 1,
  41         ARG_ULONG  = 2,
  42         ARG_ULLONG = 3,
  43         ARG_MASK   = 3,
  44
  45         FL_USRARG   = 4, /* argument is provided by user */
  46         FL_NORESULT = 8,
  47 };
  48
  49 struct bdc {
  50         uint32_t   ioc;                       /* ioctl code */
  51         const char name[sizeof("flushbufs")]; /* "--setfoo" wothout "--" */
  52         uint8_t    flags;
  53         int8_t     argval;                    /* default argument value */
  54 };
  55
  56 static const struct bdc bdcommands[] = {
  57         {
  58                 .ioc = BLKROSET,
  59                 .name = "setro",
  60                 .flags = ARG_INT + FL_NORESULT,
  61                 .argval = 1,
  62         },{
  63                 .ioc = BLKROSET,
  64                 .name = "setrw",
  65                 .flags = ARG_INT + FL_NORESULT,
  66                 .argval = 0,
  67         },{
  68                 .ioc = BLKROGET,
  69                 .name = "getro",
  70                 .flags = ARG_INT,
  71                 .argval = -1,
  72         },{
  73                 .ioc = BLKSSZGET,
  74                 .name = "getss",
  75                 .flags = ARG_INT,
  76                 .argval = -1,
  77         },{
  78                 .ioc = BLKBSZGET,
  79                 .name = "getbsz",
  80                 .flags = ARG_INT,
  81                 .argval = -1,
  82         },{
  83                 .ioc = BLKBSZSET,
  84                 .name = "setbsz",
  85                 .flags = ARG_INT + FL_NORESULT + FL_USRARG,
  86                 .argval = 0,
  87         },{
  88                 .ioc = BLKGETSIZE,
  89                 .name = "getsize",
  90                 .flags = ARG_ULONG,
  91                 .argval = -1,
  92         },{
  93                 .ioc = BLKGETSIZE64,
  94                 .name = "getsize64",
  95                 .flags = ARG_ULLONG,
  96                 .argval = -1,
  97         },{
  98                 .ioc = BLKFLSBUF,
  99                 .name = "flushbufs",
 100                 .flags = ARG_NONE + FL_NORESULT,
 101                 .argval = 0,
 102         },{
 103                 .ioc = BLKRRPART,
 104                 .name = "rereadpt",
 105                 .flags = ARG_NONE + FL_NORESULT,
 106                 .argval = 0,
 107         }
 108 };
 109
 110 static const struct bdc *find_cmd(const char *s)
 111 {
 112         int j;
 113         if (*s++ == '-')
 114                 if (*s++ == '-')
 115                         for (j = 0; j < ARRAY_SIZE(bdcommands); j++)
 116                                 if (strcmp(s, bdcommands[j].name) == 0)
 117                                         return &bdcommands[j];
 118         bb_show_usage();
 119 }
 120
 121 int blockdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 122 int blockdev_main(int argc, char **argv)
 123 {
 124         const struct bdc *bdcmd;
 125         void *ioctl_ptr;
 126         int fd;
 127         int iarg;
 128         unsigned long lu;
 129         unsigned long long llu;
 130
 131         if ((unsigned)(argc - 3) > 1) /* must have 2 or 3 args */
 132                 bb_show_usage();
 133
 134         bdcmd = find_cmd(*++argv);
 135
 136         llu = (int)bdcmd->argval;
 137         if (bdcmd->flags & FL_USRARG)
 138                 llu = xatoi_positive(*++argv);
 139         lu = llu;
 140         iarg = llu;
 141
 142         if (!*++argv)
 143                 bb_show_usage();
 144         fd = xopen(*argv, O_RDONLY);
 145
 146         ioctl_ptr = NULL;
 147         switch (bdcmd->flags & ARG_MASK) {
 148         case ARG_INT:
 149                 ioctl_ptr =  &iarg;
 150                 break;
 151         case ARG_ULONG:
 152                 ioctl_ptr = &lu;
 153                 break;
 154         case ARG_ULLONG:
 155                 ioctl_ptr = &llu;
 156                 break;
 157         }
 158
 159         if (ioctl(fd, bdcmd->ioc, ioctl_ptr) == -1)
 160                 bb_simple_perror_msg_and_die(*argv);
 161
 162         switch (bdcmd->flags & (ARG_MASK+FL_NORESULT)) {
 163         case ARG_INT:
 164                 /* Smaller code when we use long long
 165                  * (gcc tail-merges printf call)
 166                  */
 167                 printf("%lld\n", (long long)iarg);
 168                 break;
 169         case ARG_ULONG:
 170                 llu = lu;
 171                 /* FALLTHROUGH */
 172         case ARG_ULLONG:
 173                 printf("%llu\n", llu);
 174                 break;
 175         }
 176
 177         if (ENABLE_FEATURE_CLEAN_UP)
 178                 close(fd);
 179         return EXIT_SUCCESS;
 180 }