sysfs.c

   1 /*
   2  * sysfs - extract md related information from sysfs.  Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2009 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software
  20  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  */
  25
  26 #include        "mdadm.h"
  27 #include        <dirent.h>
  28 #include        <ctype.h>
  29
  30 int load_sys(char *path, char *buf)
  31 {
  32         int fd = open(path, O_RDONLY);
  33         int n;
  34         if (fd < 0)
  35                 return -1;
  36         n = read(fd, buf, 1024);
  37         close(fd);
  38         if (n <0 || n >= 1024)
  39                 return -1;
  40         buf[n] = 0;
  41         if (n && buf[n-1] == '\n')
  42                 buf[n-1] = 0;
  43         return 0;
  44 }
  45
  46 void sysfs_free(struct mdinfo *sra)
  47 {
  48         while (sra) {
  49                 struct mdinfo *sra2 = sra->next;
  50                 while (sra->devs) {
  51                         struct mdinfo *d = sra->devs;
  52                         sra->devs = d->next;
  53                         free(d);
  54                 }
  55                 free(sra);
  56                 sra = sra2;
  57         }
  58 }
  59
  60 int sysfs_open(char *devnm, char *devname, char *attr)
  61 {
  62         char fname[50];
  63         int fd;
  64
  65         sprintf(fname, "/sys/block/%s/md/", devnm);
  66         if (devname) {
  67                 strcat(fname, devname);
  68                 strcat(fname, "/");
  69         }
  70         strcat(fname, attr);
  71         fd = open(fname, O_RDWR);
  72         if (fd < 0 && errno == EACCES)
  73                 fd = open(fname, O_RDONLY);
  74         return fd;
  75 }
  76
  77 void sysfs_init(struct mdinfo *mdi, int fd, char *devnm)
  78 {
  79         mdi->sys_name[0] = 0;
  80         if (fd >= 0) {
  81                 mdu_version_t vers;
  82                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  83                         return;
  84                 devnm = fd2devnm(fd);
  85         }
  86         if (devnm == NULL)
  87                 return;
  88         strcpy(mdi->sys_name, devnm);
  89 }
  90
  91
  92 struct mdinfo *sysfs_read(int fd, char *devnm, unsigned long options)
  93 {
  94         char fname[PATH_MAX];
  95         char buf[PATH_MAX];
  96         char *base;
  97         char *dbase;
  98         struct mdinfo *sra;
  99         struct mdinfo *dev, **devp;
 100         DIR *dir = NULL;
 101         struct dirent *de;
 102
 103         sra = xcalloc(1, sizeof(*sra));
 104         sysfs_init(sra, fd, devnm);
 105         if (sra->sys_name[0] == 0) {
 106                 free(sra);
 107                 return NULL;
 108         }
 109
 110         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 111         base = fname + strlen(fname);
 112
 113         sra->devs = NULL;
 114         if (options & GET_VERSION) {
 115                 strcpy(base, "metadata_version");
 116                 if (load_sys(fname, buf))
 117                         goto abort;
 118                 if (strncmp(buf, "none", 4) == 0) {
 119                         sra->array.major_version =
 120                                 sra->array.minor_version = -1;
 121                         strcpy(sra->text_version, "");
 122                 } else if (strncmp(buf, "external:", 9) == 0) {
 123                         sra->array.major_version = -1;
 124                         sra->array.minor_version = -2;
 125                         strcpy(sra->text_version, buf+9);
 126                 } else {
 127                         sscanf(buf, "%d.%d",
 128                                &sra->array.major_version,
 129                                &sra->array.minor_version);
 130                         strcpy(sra->text_version, buf);
 131                 }
 132         }
 133         if (options & GET_LEVEL) {
 134                 strcpy(base, "level");
 135                 if (load_sys(fname, buf))
 136                         goto abort;
 137                 sra->array.level = map_name(pers, buf);
 138         }
 139         if (options & GET_LAYOUT) {
 140                 strcpy(base, "layout");
 141                 if (load_sys(fname, buf))
 142                         goto abort;
 143                 sra->array.layout = strtoul(buf, NULL, 0);
 144         }
 145         if (options & GET_DISKS) {
 146                 strcpy(base, "raid_disks");
 147                 if (load_sys(fname, buf))
 148                         goto abort;
 149                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 150         }
 151         if (options & GET_DEGRADED) {
 152                 strcpy(base, "degraded");
 153                 if (load_sys(fname, buf))
 154                         goto abort;
 155                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 156         }
 157         if (options & GET_COMPONENT) {
 158                 strcpy(base, "component_size");
 159                 if (load_sys(fname, buf))
 160                         goto abort;
 161                 sra->component_size = strtoull(buf, NULL, 0);
 162                 /* sysfs reports "K", but we want sectors */
 163                 sra->component_size *= 2;
 164         }
 165         if (options & GET_CHUNK) {
 166                 strcpy(base, "chunk_size");
 167                 if (load_sys(fname, buf))
 168                         goto abort;
 169                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 170         }
 171         if (options & GET_CACHE) {
 172                 strcpy(base, "stripe_cache_size");
 173                 if (load_sys(fname, buf))
 174                         /* Probably level doesn't support it */
 175                         sra->cache_size = 0;
 176                 else
 177                         sra->cache_size = strtoul(buf, NULL, 0);
 178         }
 179         if (options & GET_MISMATCH) {
 180                 strcpy(base, "mismatch_cnt");
 181                 if (load_sys(fname, buf))
 182                         goto abort;
 183                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 184         }
 185         if (options & GET_SAFEMODE) {
 186                 int scale = 1;
 187                 int dot = 0;
 188                 unsigned i;
 189                 unsigned long msec;
 190                 size_t len;
 191
 192                 strcpy(base, "safe_mode_delay");
 193                 if (load_sys(fname, buf))
 194                         goto abort;
 195
 196                 /* remove a period, and count digits after it */
 197                 len = strlen(buf);
 198                 for (i = 0; i < len; i++) {
 199                         if (dot) {
 200                                 if (isdigit(buf[i])) {
 201                                         buf[i-1] = buf[i];
 202                                         scale *= 10;
 203                                 }
 204                                 buf[i] = 0;
 205                         } else if (buf[i] == '.') {
 206                                 dot=1;
 207                                 buf[i] = 0;
 208                         }
 209                 }
 210                 msec = strtoul(buf, NULL, 10);
 211                 msec = (msec * 1000) / scale;
 212                 sra->safe_mode_delay = msec;
 213         }
 214         if (options & GET_BITMAP_LOCATION) {
 215                 strcpy(base, "bitmap/location");
 216                 if (load_sys(fname, buf))
 217                         goto abort;
 218                 if (strncmp(buf, "file", 4) == 0)
 219                         sra->bitmap_offset = 1;
 220                 else if (strncmp(buf, "none", 4) == 0)
 221                         sra->bitmap_offset = 0;
 222                 else if (buf[0] == '+')
 223                         sra->bitmap_offset = strtol(buf+1, NULL, 10);
 224                 else
 225                         goto abort;
 226         }
 227
 228         if (! (options & GET_DEVS))
 229                 return sra;
 230
 231         /* Get all the devices as well */
 232         *base = 0;
 233         dir = opendir(fname);
 234         if (!dir)
 235                 goto abort;
 236         sra->array.spare_disks = 0;
 237
 238         devp = &sra->devs;
 239         sra->devs = NULL;
 240         while ((de = readdir(dir)) != NULL) {
 241                 char *ep;
 242                 if (de->d_ino == 0 ||
 243                     strncmp(de->d_name, "dev-", 4) != 0)
 244                         continue;
 245                 strcpy(base, de->d_name);
 246                 dbase = base + strlen(base);
 247                 *dbase++ = '/';
 248
 249                 dev = xmalloc(sizeof(*dev));
 250
 251                 /* Always get slot, major, minor */
 252                 strcpy(dbase, "slot");
 253                 if (load_sys(fname, buf)) {
 254                         /* hmm... unable to read 'slot' maybe the device
 255                          * is going away?
 256                          */
 257                         strcpy(dbase, "block");
 258                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 259                             errno != ENAMETOOLONG) {
 260                                 /* ...yup device is gone */
 261                                 free(dev);
 262                                 continue;
 263                         } else {
 264                                 /* slot is unreadable but 'block' link
 265                                  * still intact... something bad is happening
 266                                  * so abort
 267                                  */
 268                                 free(dev);
 269                                 goto abort;
 270                         }
 271
 272                 }
 273                 strcpy(dev->sys_name, de->d_name);
 274                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 275                 if (*ep) dev->disk.raid_disk = -1;
 276
 277                 strcpy(dbase, "block/dev");
 278                 if (load_sys(fname, buf)) {
 279                         /* assume this is a stale reference to a hot
 280                          * removed device
 281                          */
 282                         free(dev);
 283                         continue;
 284                 }
 285                 sra->array.nr_disks++;
 286                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 287
 288                 /* special case check for block devices that can go 'offline' */
 289                 strcpy(dbase, "block/device/state");
 290                 if (load_sys(fname, buf) == 0 &&
 291                     strncmp(buf, "offline", 7) == 0) {
 292                         free(dev);
 293                         continue;
 294                 }
 295
 296                 /* finally add this disk to the array */
 297                 *devp = dev;
 298                 devp = & dev->next;
 299                 dev->next = NULL;
 300
 301                 if (options & GET_OFFSET) {
 302                         strcpy(dbase, "offset");
 303                         if (load_sys(fname, buf))
 304                                 goto abort;
 305                         dev->data_offset = strtoull(buf, NULL, 0);
 306                         strcpy(dbase, "new_offset");
 307                         if (load_sys(fname, buf) == 0)
 308                                 dev->new_data_offset = strtoull(buf, NULL, 0);
 309                         else
 310                                 dev->new_data_offset = dev->data_offset;
 311                 }
 312                 if (options & GET_SIZE) {
 313                         strcpy(dbase, "size");
 314                         if (load_sys(fname, buf))
 315                                 goto abort;
 316                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 317                 }
 318                 if (options & GET_STATE) {
 319                         dev->disk.state = 0;
 320                         strcpy(dbase, "state");
 321                         if (load_sys(fname, buf))
 322                                 goto abort;
 323                         if (strstr(buf, "in_sync"))
 324                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 325                         if (strstr(buf, "faulty"))
 326                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 327                         if (dev->disk.state == 0)
 328                                 sra->array.spare_disks++;
 329                 }
 330                 if (options & GET_ERROR) {
 331                         strcpy(buf, "errors");
 332                         if (load_sys(fname, buf))
 333                                 goto abort;
 334                         dev->errors = strtoul(buf, NULL, 0);
 335                 }
 336         }
 337         closedir(dir);
 338         return sra;
 339
 340  abort:
 341         if (dir)
 342                 closedir(dir);
 343         sysfs_free(sra);
 344         return NULL;
 345 }
 346
 347 int sysfs_attr_match(const char *attr, const char *str)
 348 {
 349         /* See if attr, read from a sysfs file, matches
 350          * str.  They must either be the same, or attr can
 351          * have a trailing newline or comma
 352          */
 353         while (*attr && *str && *attr == *str) {
 354                 attr++;
 355                 str++;
 356         }
 357
 358         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 359                 return 0;
 360         return 1;
 361 }
 362
 363 int sysfs_match_word(const char *word, char **list)
 364 {
 365         int n;
 366         for (n=0; list[n]; n++)
 367                 if (sysfs_attr_match(word, list[n]))
 368                         break;
 369         return n;
 370 }
 371
 372 unsigned long long get_component_size(int fd)
 373 {
 374         /* Find out the component size of the array.
 375          * We cannot trust GET_ARRAY_INFO ioctl as it's
 376          * size field is only 32bits.
 377          * So look in /sys/block/mdXXX/md/component_size
 378          *
 379          * This returns in units of sectors.
 380          */
 381         struct stat stb;
 382         char fname[50];
 383         int n;
 384         if (fstat(fd, &stb)) return 0;
 385         if (major(stb.st_rdev) != (unsigned)get_mdp_major())
 386                 sprintf(fname, "/sys/block/md%d/md/component_size",
 387                         (int)minor(stb.st_rdev));
 388         else
 389                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 390                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 391         fd = open(fname, O_RDONLY);
 392         if (fd < 0)
 393                 return 0;
 394         n = read(fd, fname, sizeof(fname));
 395         close(fd);
 396         if (n < 0 || n == sizeof(fname))
 397                 return 0;
 398         fname[n] = 0;
 399         return strtoull(fname, NULL, 10) * 2;
 400 }
 401
 402 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 403                   char *name, char *val)
 404 {
 405         char fname[50];
 406         unsigned int n;
 407         int fd;
 408
 409         sprintf(fname, "/sys/block/%s/md/%s/%s",
 410                 sra->sys_name, dev?dev->sys_name:"", name);
 411         fd = open(fname, O_WRONLY);
 412         if (fd < 0)
 413                 return -1;
 414         n = write(fd, val, strlen(val));
 415         close(fd);
 416         if (n != strlen(val)) {
 417                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 418                         val, fname, strerror(errno));
 419                 return -1;
 420         }
 421         return 0;
 422 }
 423
 424 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 425                   char *name, unsigned long long val)
 426 {
 427         char valstr[50];
 428         sprintf(valstr, "%llu", val);
 429         return sysfs_set_str(sra, dev, name, valstr);
 430 }
 431
 432 int sysfs_set_num_signed(struct mdinfo *sra, struct mdinfo *dev,
 433                          char *name, long long val)
 434 {
 435         char valstr[50];
 436         sprintf(valstr, "%lli", val);
 437         return sysfs_set_str(sra, dev, name, valstr);
 438 }
 439
 440 int sysfs_uevent(struct mdinfo *sra, char *event)
 441 {
 442         char fname[50];
 443         int n;
 444         int fd;
 445
 446         sprintf(fname, "/sys/block/%s/uevent",
 447                 sra->sys_name);
 448         fd = open(fname, O_WRONLY);
 449         if (fd < 0)
 450                 return -1;
 451         n = write(fd, event, strlen(event));
 452         close(fd);
 453         if (n != (int)strlen(event)) {
 454                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 455                         event, fname, strerror(errno));
 456                 return -1;
 457         }
 458         return 0;
 459 }
 460
 461 int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
 462 {
 463         char fname[50];
 464         struct stat st;
 465
 466         sprintf(fname, "/sys/block/%s/md/%s/%s",
 467                 sra->sys_name, dev?dev->sys_name:"", name);
 468
 469         return stat(fname, &st) == 0;
 470 }
 471
 472 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
 473                        char *name)
 474 {
 475         char fname[50];
 476         int fd;
 477
 478         sprintf(fname, "/sys/block/%s/md/%s/%s",
 479                 sra->sys_name, dev?dev->sys_name:"", name);
 480         fd = open(fname, O_RDWR);
 481         if (fd < 0)
 482                 fd = open(fname, O_RDONLY);
 483         return fd;
 484 }
 485
 486 int sysfs_fd_get_ll(int fd, unsigned long long *val)
 487 {
 488         char buf[50];
 489         int n;
 490         char *ep;
 491
 492         lseek(fd, 0, 0);
 493         n = read(fd, buf, sizeof(buf));
 494         if (n <= 0)
 495                 return -2;
 496         buf[n] = 0;
 497         *val = strtoull(buf, &ep, 0);
 498         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 499                 return -1;
 500         return 0;
 501 }
 502
 503 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 504                        char *name, unsigned long long *val)
 505 {
 506         int n;
 507         int fd;
 508
 509         fd = sysfs_get_fd(sra, dev, name);
 510         if (fd < 0)
 511                 return -1;
 512         n = sysfs_fd_get_ll(fd, val);
 513         close(fd);
 514         return n;
 515 }
 516
 517 int sysfs_fd_get_str(int fd, char *val, int size)
 518 {
 519         int n;
 520
 521         lseek(fd, 0, 0);
 522         n = read(fd, val, size);
 523         if (n <= 0)
 524                 return -1;
 525         val[n] = 0;
 526         return n;
 527 }
 528
 529 int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
 530                        char *name, char *val, int size)
 531 {
 532         int n;
 533         int fd;
 534
 535         fd = sysfs_get_fd(sra, dev, name);
 536         if (fd < 0)
 537                 return -1;
 538         n = sysfs_fd_get_str(fd, val, size);
 539         close(fd);
 540         return n;
 541 }
 542
 543 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 544 {
 545         unsigned long sec;
 546         unsigned long msec;
 547         char delay[30];
 548
 549         sec = ms / 1000;
 550         msec = ms % 1000;
 551
 552         sprintf(delay, "%ld.%03ld\n", sec, msec);
 553         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 554         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 555 }
 556
 557 int sysfs_set_array(struct mdinfo *info, int vers)
 558 {
 559         int rv = 0;
 560         char ver[100];
 561         int raid_disks = info->array.raid_disks;
 562
 563         ver[0] = 0;
 564         if (info->array.major_version == -1 &&
 565             info->array.minor_version == -2) {
 566                 char buf[1024];
 567
 568                 strcat(strcpy(ver, "external:"), info->text_version);
 569
 570                 /* meta version might already be set if we are setting
 571                  * new geometry for a reshape.  In that case we don't
 572                  * want to over-write the 'readonly' flag that is
 573                  * stored in the metadata version.  So read the current
 574                  * version first, and preserve the flag
 575                  */
 576                 if (sysfs_get_str(info, NULL, "metadata_version",
 577                                   buf, 1024) > 0)
 578                         if (strlen(buf) >= 9 && buf[9] == '-')
 579                                 ver[9] = '-';
 580
 581                 if ((vers % 100) < 2 ||
 582                     sysfs_set_str(info, NULL, "metadata_version",
 583                                   ver) < 0) {
 584                         pr_err("This kernel does not "
 585                                 "support external metadata.\n");
 586                         return 1;
 587                 }
 588         }
 589         if (info->array.level < 0)
 590                 return 0; /* FIXME */
 591         rv |= sysfs_set_str(info, NULL, "level",
 592                             map_num(pers, info->array.level));
 593         if (info->reshape_active && info->delta_disks != UnSet)
 594                 raid_disks -= info->delta_disks;
 595         rv |= sysfs_set_num(info, NULL, "raid_disks", raid_disks);
 596         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 597         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 598         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 599         if (info->custom_array_size) {
 600                 int rc;
 601
 602                 rc = sysfs_set_num(info, NULL, "array_size",
 603                                    info->custom_array_size/2);
 604                 if (rc && errno == ENOENT) {
 605                         pr_err("This kernel does not "
 606                                 "have the md/array_size attribute, "
 607                                 "the array may be larger than expected\n");
 608                         rc = 0;
 609                 }
 610                 rv |= rc;
 611         }
 612
 613         if (info->array.level > 0)
 614                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 615
 616         if (info->reshape_active) {
 617                 rv |= sysfs_set_num(info, NULL, "reshape_position",
 618                                     info->reshape_progress);
 619                 rv |= sysfs_set_num(info, NULL, "chunk_size", info->new_chunk);
 620                 rv |= sysfs_set_num(info, NULL, "layout", info->new_layout);
 621                 rv |= sysfs_set_num(info, NULL, "raid_disks",
 622                                     info->array.raid_disks);
 623                 /* We don't set 'new_level' here.  That can only happen
 624                  * once the reshape completes.
 625                  */
 626         }
 627         return rv;
 628 }
 629
 630 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 631 {
 632         char dv[PATH_MAX];
 633         char nm[PATH_MAX];
 634         char *dname;
 635         int rv;
 636
 637         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 638         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 639         if (rv)
 640                 return rv;
 641
 642         memset(nm, 0, sizeof(nm));
 643         dname = devid2devnm(makedev(sd->disk.major, sd->disk.minor));
 644         strcpy(sd->sys_name, "dev-");
 645         strcpy(sd->sys_name+4, dname);
 646
 647         /* test write to see if 'recovery_start' is available */
 648         if (resume && sd->recovery_start < MaxSector &&
 649             sysfs_set_num(sra, sd, "recovery_start", 0)) {
 650                 sysfs_set_str(sra, sd, "state", "remove");
 651                 return -1;
 652         }
 653
 654         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 655         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 656         if (sra->array.level != LEVEL_CONTAINER) {
 657                 if (sd->recovery_start == MaxSector)
 658                         /* This can correctly fail if array isn't started,
 659                          * yet, so just ignore status for now.
 660                          */
 661                         sysfs_set_str(sra, sd, "state", "insync");
 662                 if (sd->disk.raid_disk >= 0)
 663                         rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 664                 if (resume)
 665                         sysfs_set_num(sra, sd, "recovery_start", sd->recovery_start);
 666         }
 667         return rv;
 668 }
 669
 670 #if 0
 671 int sysfs_disk_to_sg(int fd)
 672 {
 673         /* from an open block device, try find and open its corresponding
 674          * scsi_generic interface
 675          */
 676         struct stat st;
 677         char path[256];
 678         char sg_path[256];
 679         char sg_major_minor[8];
 680         char *c;
 681         DIR *dir;
 682         struct dirent *de;
 683         int major, minor, rv;
 684
 685         if (fstat(fd, &st))
 686                 return -1;
 687
 688         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 689                  major(st.st_rdev), minor(st.st_rdev));
 690
 691         dir = opendir(path);
 692         if (!dir)
 693                 return -1;
 694
 695         de = readdir(dir);
 696         while (de) {
 697                 if (strncmp("scsi_generic:", de->d_name,
 698                             strlen("scsi_generic:")) == 0)
 699                         break;
 700                 de = readdir(dir);
 701         }
 702         closedir(dir);
 703
 704         if (!de)
 705                 return -1;
 706
 707         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 708         fd = open(sg_path, O_RDONLY);
 709         if (fd < 0)
 710                 return fd;
 711
 712         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 713         close(fd);
 714         if (rv < 0)
 715                 return -1;
 716         else
 717                 sg_major_minor[rv - 1] = '\0';
 718
 719         c = strchr(sg_major_minor, ':');
 720         *c = '\0';
 721         c++;
 722         major = strtol(sg_major_minor, NULL, 10);
 723         minor = strtol(c, NULL, 10);
 724         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 725                  (int) getpid(), major, minor);
 726         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 727                         fd = open(path, O_RDONLY);
 728                         unlink(path);
 729                         return fd;
 730         }
 731
 732         return -1;
 733 }
 734 #endif
 735
 736 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 737 {
 738         /* from an open block device, try to retrieve it scsi_id */
 739         struct stat st;
 740         char path[256];
 741         DIR *dir;
 742         struct dirent *de;
 743         int host, bus, target, lun;
 744
 745         if (fstat(fd, &st))
 746                 return 1;
 747
 748         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
 749                  major(st.st_rdev), minor(st.st_rdev));
 750
 751         dir = opendir(path);
 752         if (!dir)
 753                 return 1;
 754
 755         for (de = readdir(dir); de; de = readdir(dir)) {
 756                 int count;
 757
 758                 if (de->d_type != DT_DIR)
 759                         continue;
 760
 761                 count = sscanf(de->d_name, "%d:%d:%d:%d", &host, &bus, &target, &lun);
 762                 if (count == 4)
 763                         break;
 764         }
 765         closedir(dir);
 766
 767         if (!de)
 768                 return 1;
 769
 770         *id = (host << 24) | (bus << 16) | (target << 8) | (lun << 0);
 771         return 0;
 772 }
 773
 774
 775 int sysfs_unique_holder(char *devnm, long rdev)
 776 {
 777         /* Check that devnm is a holder of rdev,
 778          * and is the only holder.
 779          * we should be locked against races by
 780          * an O_EXCL on devnm
 781          * Return values:
 782          *  0 - not unique, not even a holder
 783          *  1 - unique, this is the only holder.
 784          *  2/3 - not unique, there is another holder
 785          * -1 - error, cannot find the holders
 786          */
 787         DIR *dir;
 788         struct dirent *de;
 789         char dirname[100];
 790         char l;
 791         int ret = 0;
 792         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 793                 major(rdev), minor(rdev));
 794         dir = opendir(dirname);
 795         if (!dir)
 796                 return -1;
 797         l = strlen(dirname);
 798         while ((de = readdir(dir)) != NULL) {
 799                 char buf[100];
 800                 char *sl;
 801                 int n;
 802
 803                 if (de->d_ino == 0)
 804                         continue;
 805                 if (de->d_name[0] == '.')
 806                         continue;
 807                 strcpy(dirname+l, "/");
 808                 strcat(dirname+l, de->d_name);
 809                 n = readlink(dirname, buf, sizeof(buf)-1);
 810                 if (n <= 0)
 811                         continue;
 812                 buf[n] = 0;
 813                 sl = strrchr(buf, '/');
 814                 if (!sl)
 815                         continue;
 816                 sl++;
 817
 818                 if (strcmp(devnm, sl) == 0)
 819                         ret |= 1;
 820                 else
 821                         ret |= 2;
 822         }
 823         closedir(dir);
 824         return ret;
 825 }
 826
 827 int sysfs_freeze_array(struct mdinfo *sra)
 828 {
 829         /* Try to freeze resync/rebuild on this array/container.
 830          * Return -1 if the array is busy,
 831          * return 0 if this kernel doesn't support 'frozen'
 832          * return 1 if it worked.
 833          */
 834         char buf[20];
 835
 836         if (!sysfs_attribute_available(sra, NULL, "sync_action"))
 837                 return 1; /* no sync_action == frozen */
 838         if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
 839                 return 0;
 840         if (strcmp(buf, "frozen\n") == 0)
 841                 /* Already frozen */
 842                 return 0;
 843         if (strcmp(buf, "idle\n") != 0)
 844                 return -1;
 845         if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
 846                 return 0;
 847         return 1;
 848 }