lib/blkdev.c

   1 /*
   2  * No copyright is claimed.  This code is in the public domain; do with
   3  * it what you wish.
   4  *
   5  * Written by Karel Zak <kzak@redhat.com>
   6  */
   7 #include <sys/types.h>
   8 #include <sys/stat.h>
   9 #include <sys/ioctl.h>
  10 #include <unistd.h>
  11 #include <stdint.h>
  12
  13 #ifdef HAVE_LINUX_FD_H
  14 #include <linux/fd.h>
  15 #endif
  16
  17 #ifdef HAVE_SYS_DISKLABEL_H
  18 #include <sys/disklabel.h>
  19 #endif
  20
  21 #ifdef HAVE_SYS_DISK_H
  22 # include <sys/disk.h>
  23 #endif
  24
  25 #ifndef EBADFD
  26 # define EBADFD 77              /* File descriptor in bad state */
  27 #endif
  28
  29 #include "blkdev.h"
  30 #include "c.h"
  31 #include "linux_version.h"
  32 #include "fileutils.h"
  33 #include "nls.h"
  34
  35 static long
  36 blkdev_valid_offset (int fd, off_t offset) {
  37         char ch;
  38
  39         if (lseek (fd, offset, 0) < 0)
  40                 return 0;
  41         if (read (fd, &ch, 1) < 1)
  42                 return 0;
  43         return 1;
  44 }
  45
  46 int is_blkdev(int fd)
  47 {
  48         struct stat st;
  49         return (fstat(fd, &st) == 0 && S_ISBLK(st.st_mode));
  50 }
  51
  52 off_t
  53 blkdev_find_size (int fd) {
  54         uintmax_t high, low = 0;
  55
  56         for (high = 1024; blkdev_valid_offset (fd, high); ) {
  57                 if (high == UINTMAX_MAX)
  58                         return -1;
  59
  60                 low = high;
  61
  62                 if (high >= UINTMAX_MAX/2)
  63                         high = UINTMAX_MAX;
  64                 else
  65                         high *= 2;
  66         }
  67
  68         while (low < high - 1)
  69         {
  70                 uintmax_t mid = (low + high) / 2;
  71
  72                 if (blkdev_valid_offset (fd, mid))
  73                         low = mid;
  74                 else
  75                         high = mid;
  76         }
  77         blkdev_valid_offset (fd, 0);
  78         return (low + 1);
  79 }
  80
  81 /* get size in bytes */
  82 int
  83 blkdev_get_size(int fd, unsigned long long *bytes)
  84 {
  85 #ifdef DKIOCGETBLOCKCOUNT
  86         /* Apple Darwin */
  87         if (ioctl(fd, DKIOCGETBLOCKCOUNT, bytes) >= 0) {
  88                 *bytes <<= 9;
  89                 return 0;
  90         }
  91 #endif
  92
  93 #ifdef BLKGETSIZE64
  94         if (ioctl(fd, BLKGETSIZE64, bytes) >= 0)
  95                 return 0;
  96 #endif
  97
  98 #ifdef BLKGETSIZE
  99         {
 100                 unsigned long size;
 101
 102                 if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
 103                         *bytes = ((unsigned long long)size << 9);
 104                         return 0;
 105                 }
 106         }
 107
 108 #endif /* BLKGETSIZE */
 109
 110 #ifdef DIOCGMEDIASIZE
 111         /* FreeBSD */
 112         if (ioctl(fd, DIOCGMEDIASIZE, bytes) >= 0)
 113                 return 0;
 114 #endif
 115
 116 #ifdef FDGETPRM
 117         {
 118                 struct floppy_struct this_floppy;
 119
 120                 if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) {
 121                         *bytes = ((unsigned long long) this_floppy.size) << 9;
 122                         return 0;
 123                 }
 124         }
 125 #endif /* FDGETPRM */
 126
 127 #if defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO)
 128         {
 129                 /*
 130                  * This code works for FreeBSD 4.11 i386, except for the full device
 131                  * (such as /dev/ad0). It doesn't work properly for newer FreeBSD
 132                  * though. FreeBSD >= 5.0 should be covered by the DIOCGMEDIASIZE
 133                  * above however.
 134                  *
 135                  * Note that FreeBSD >= 4.0 has disk devices as unbuffered (raw,
 136                  * character) devices, so we need to check for S_ISCHR, too.
 137                  */
 138                 int part = -1;
 139                 struct disklabel lab;
 140                 struct partition *pp;
 141                 struct stat st;
 142
 143                 if ((fstat(fd, &st) >= 0) &&
 144                     (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)))
 145                         part = st.st_rdev & 7;
 146
 147                 if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
 148                         pp = &lab.d_partitions[part];
 149                         if (pp->p_size) {
 150                                  *bytes = pp->p_size << 9;
 151                                  return 0;
 152                         }
 153                 }
 154         }
 155 #endif /* defined(HAVE_SYS_DISKLABEL_H) && defined(DIOCGDINFO) */
 156
 157         {
 158                 struct stat st;
 159
 160                 if (fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
 161                         *bytes = st.st_size;
 162                         return 0;
 163                 }
 164                 if (!S_ISBLK(st.st_mode))
 165                         return -1;
 166         }
 167
 168         *bytes = blkdev_find_size(fd);
 169         return 0;
 170 }
 171
 172 /* get 512-byte sector count */
 173 int
 174 blkdev_get_sectors(int fd, unsigned long long *sectors)
 175 {
 176         unsigned long long bytes;
 177
 178         if (blkdev_get_size(fd, &bytes) == 0) {
 179                 *sectors = (bytes >> 9);
 180                 return 0;
 181         }
 182
 183         return -1;
 184 }
 185
 186 /*
 187  * Get logical sector size.
 188  *
 189  * This is the smallest unit the storage device can
 190  * address. It is typically 512 bytes.
 191  */
 192 #ifdef BLKSSZGET
 193 int blkdev_get_sector_size(int fd, int *sector_size)
 194 {
 195         if (ioctl(fd, BLKSSZGET, sector_size) >= 0)
 196                 return 0;
 197         return -1;
 198 }
 199 #else
 200 int blkdev_get_sector_size(int fd __attribute__((__unused__)), int *sector_size)
 201 {
 202         *sector_size = DEFAULT_SECTOR_SIZE;
 203         return 0;
 204 }
 205 #endif
 206
 207 /*
 208  * Get physical block device size. The BLKPBSZGET is supported since Linux
 209  * 2.6.32. For old kernels is probably the best to assume that physical sector
 210  * size is the same as logical sector size.
 211  *
 212  * Example:
 213  *
 214  * rc = blkdev_get_physector_size(fd, &physec);
 215  * if (rc || physec == 0) {
 216  *      rc = blkdev_get_sector_size(fd, &physec);
 217  *      if (rc)
 218  *              physec = DEFAULT_SECTOR_SIZE;
 219  * }
 220  */
 221 #ifdef BLKPBSZGET
 222 int blkdev_get_physector_size(int fd, int *sector_size)
 223 {
 224         if (ioctl(fd, BLKPBSZGET, &sector_size) >= 0)
 225                 return 0;
 226         return -1;
 227 }
 228 #else
 229 int blkdev_get_physector_size(int fd __attribute__((__unused__)), int *sector_size)
 230 {
 231         *sector_size = DEFAULT_SECTOR_SIZE;
 232         return 0;
 233 }
 234 #endif
 235
 236 /*
 237  * Return the alignment status of a device
 238  */
 239 #ifdef BLKALIGNOFF
 240 int blkdev_is_misaligned(int fd)
 241 {
 242         int aligned;
 243
 244         if (ioctl(fd, BLKALIGNOFF, &aligned) < 0)
 245                 return 0;                       /* probably kernel < 2.6.32 */
 246         /*
 247          * Note that kernel returns -1 as alignment offset if no compatible
 248          * sizes and alignments exist for stacked devices
 249          */
 250         return aligned != 0 ? 1 : 0;
 251 }
 252 #else
 253 int blkdev_is_misaligned(int fd __attribute__((__unused__)))
 254 {
 255         return 0;
 256 }
 257 #endif
 258
 259 int open_blkdev_or_file(const struct stat *st, const char *name, const int oflag)
 260 {
 261         int fd;
 262
 263         if (S_ISBLK(st->st_mode)) {
 264                 fd = open(name, oflag | O_EXCL);
 265         } else
 266                 fd = open(name, oflag);
 267         if (-1 < fd && !is_same_inode(fd, st)) {
 268                 close(fd);
 269                 errno = EBADFD;
 270                 return -1;
 271         }
 272         if (-1 < fd && S_ISBLK(st->st_mode) && blkdev_is_misaligned(fd))
 273                 warnx(_("warning: %s is misaligned"), name);
 274         return fd;
 275 }
 276
 277 #ifdef CDROM_GET_CAPABILITY
 278 int blkdev_is_cdrom(int fd)
 279 {
 280         int ret;
 281
 282         if ((ret = ioctl(fd, CDROM_GET_CAPABILITY, NULL)) < 0)
 283                 return 0;
 284         else
 285                 return ret;
 286 }
 287 #else
 288 int blkdev_is_cdrom(int fd __attribute__((__unused__)))
 289 {
 290         return 0;
 291 }
 292 #endif
 293
 294 /*
 295  * Get kernel's interpretation of the device's geometry.
 296  *
 297  * Returns the heads and sectors - but not cylinders
 298  * as it's truncated for disks with more than 65535 tracks.
 299  *
 300  * Note that this is deprecated in favor of LBA addressing.
 301  */
 302 #ifdef HDIO_GETGEO
 303 int blkdev_get_geometry(int fd, unsigned int *h, unsigned int *s)
 304 {
 305         struct hd_geometry geometry;
 306
 307         if (ioctl(fd, HDIO_GETGEO, &geometry) == 0) {
 308                 *h = geometry.heads;
 309                 *s = geometry.sectors;
 310                 return 0;
 311         }
 312 #else
 313 int blkdev_get_geometry(int fd __attribute__((__unused__)),
 314                 unsigned int *h, unsigned int *s)
 315 {
 316         *h = 0;
 317         *s = 0;
 318 #endif
 319         return -1;
 320 }
 321
 322 /*
 323  * Convert scsi type to human readable string.
 324  */
 325 const char *blkdev_scsi_type_to_name(int type)
 326 {
 327         switch (type) {
 328         case SCSI_TYPE_DISK:
 329                 return "disk";
 330         case SCSI_TYPE_TAPE:
 331                 return "tape";
 332         case SCSI_TYPE_PRINTER:
 333                 return "printer";
 334         case SCSI_TYPE_PROCESSOR:
 335                 return "processor";
 336         case SCSI_TYPE_WORM:
 337                 return "worm";
 338         case SCSI_TYPE_ROM:
 339                 return "rom";
 340         case SCSI_TYPE_SCANNER:
 341                 return "scanner";
 342         case SCSI_TYPE_MOD:
 343                 return "mo-disk";
 344         case SCSI_TYPE_MEDIUM_CHANGER:
 345                 return "changer";
 346         case SCSI_TYPE_COMM:
 347                 return "comm";
 348         case SCSI_TYPE_RAID:
 349                 return "raid";
 350         case SCSI_TYPE_ENCLOSURE:
 351                 return "enclosure";
 352         case SCSI_TYPE_RBC:
 353                 return "rbc";
 354         case SCSI_TYPE_OSD:
 355                 return "osd";
 356         case SCSI_TYPE_NO_LUN:
 357                 return "no-lun";
 358         default:
 359                 break;
 360         }
 361         return NULL;
 362 }
 363
 364 #ifdef TEST_PROGRAM_BLKDEV
 365 #include <stdio.h>
 366 #include <stdlib.h>
 367 #include <fcntl.h>
 368 int
 369 main(int argc, char **argv)
 370 {
 371         unsigned long long bytes;
 372         unsigned long long sectors;
 373         int sector_size, phy_sector_size;
 374         int fd;
 375
 376         if (argc != 2) {
 377                 fprintf(stderr, "usage: %s device\n", argv[0]);
 378                 exit(EXIT_FAILURE);
 379         }
 380
 381         if ((fd = open(argv[1], O_RDONLY|O_CLOEXEC)) < 0)
 382                 err(EXIT_FAILURE, "open %s failed", argv[1]);
 383
 384         if (blkdev_get_size(fd, &bytes) < 0)
 385                 err(EXIT_FAILURE, "blkdev_get_size() failed");
 386         if (blkdev_get_sectors(fd, &sectors) < 0)
 387                 err(EXIT_FAILURE, "blkdev_get_sectors() failed");
 388         if (blkdev_get_sector_size(fd, &sector_size) < 0)
 389                 err(EXIT_FAILURE, "blkdev_get_sector_size() failed");
 390         if (blkdev_get_physector_size(fd, &phy_sector_size) < 0)
 391                 err(EXIT_FAILURE, "blkdev_get_physector_size() failed");
 392
 393         printf("          bytes: %llu\n", bytes);
 394         printf("        sectors: %llu\n", sectors);
 395         printf("    sector size: %d\n", sector_size);
 396         printf("phy-sector size: %d\n", phy_sector_size);
 397
 398         return EXIT_SUCCESS;
 399 }
 400 #endif /* TEST_PROGRAM_BLKDEV */