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(int devnum, char *devname, char *attr)
  61 {
  62         char fname[50];
  63         int fd;
  64         char *mdname = devnum2devname(devnum);
  65
  66         if (!mdname)
  67                 return -1;
  68
  69         sprintf(fname, "/sys/block/%s/md/", mdname);
  70         if (devname) {
  71                 strcat(fname, devname);
  72                 strcat(fname, "/");
  73         }
  74         strcat(fname, attr);
  75         fd = open(fname, O_RDWR);
  76         if (fd < 0 && errno == EACCES)
  77                 fd = open(fname, O_RDONLY);
  78         free(mdname);
  79         return fd;
  80 }
  81
  82 void sysfs_init(struct mdinfo *mdi, int fd, int devnum)
  83 {
  84         mdi->sys_name[0] = 0;
  85         if (fd >= 0) {
  86                 mdu_version_t vers;
  87                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  88                         return;
  89                 devnum = fd2devnum(fd);
  90         }
  91         if (devnum == NoMdDev)
  92                 return;
  93         fmt_devname(mdi->sys_name, devnum);
  94 }
  95
  96
  97 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
  98 {
  99         char fname[PATH_MAX];
 100         char buf[PATH_MAX];
 101         char *base;
 102         char *dbase;
 103         struct mdinfo *sra;
 104         struct mdinfo *dev;
 105         DIR *dir = NULL;
 106         struct dirent *de;
 107
 108         sra = malloc(sizeof(*sra));
 109         if (sra == NULL)
 110                 return sra;
 111         memset(sra, 0, sizeof(*sra));
 112         sysfs_init(sra, fd, devnum);
 113         if (sra->sys_name[0] == 0) {
 114                 free(sra);
 115                 return NULL;
 116         }
 117
 118         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 119         base = fname + strlen(fname);
 120
 121         sra->devs = NULL;
 122         if (options & GET_VERSION) {
 123                 strcpy(base, "metadata_version");
 124                 if (load_sys(fname, buf))
 125                         goto abort;
 126                 if (strncmp(buf, "none", 4) == 0) {
 127                         sra->array.major_version =
 128                                 sra->array.minor_version = -1;
 129                         strcpy(sra->text_version, "");
 130                 } else if (strncmp(buf, "external:", 9) == 0) {
 131                         sra->array.major_version = -1;
 132                         sra->array.minor_version = -2;
 133                         strcpy(sra->text_version, buf+9);
 134                 } else {
 135                         sscanf(buf, "%d.%d",
 136                                &sra->array.major_version,
 137                                &sra->array.minor_version);
 138                         strcpy(sra->text_version, buf);
 139                 }
 140         }
 141         if (options & GET_LEVEL) {
 142                 strcpy(base, "level");
 143                 if (load_sys(fname, buf))
 144                         goto abort;
 145                 sra->array.level = map_name(pers, buf);
 146         }
 147         if (options & GET_LAYOUT) {
 148                 strcpy(base, "layout");
 149                 if (load_sys(fname, buf))
 150                         goto abort;
 151                 sra->array.layout = strtoul(buf, NULL, 0);
 152         }
 153         if (options & GET_DISKS) {
 154                 strcpy(base, "raid_disks");
 155                 if (load_sys(fname, buf))
 156                         goto abort;
 157                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 158         }
 159         if (options & GET_DEGRADED) {
 160                 strcpy(base, "degraded");
 161                 if (load_sys(fname, buf))
 162                         goto abort;
 163                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 164         }
 165         if (options & GET_COMPONENT) {
 166                 strcpy(base, "component_size");
 167                 if (load_sys(fname, buf))
 168                         goto abort;
 169                 sra->component_size = strtoull(buf, NULL, 0);
 170                 /* sysfs reports "K", but we want sectors */
 171                 sra->component_size *= 2;
 172         }
 173         if (options & GET_CHUNK) {
 174                 strcpy(base, "chunk_size");
 175                 if (load_sys(fname, buf))
 176                         goto abort;
 177                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 178         }
 179         if (options & GET_CACHE) {
 180                 strcpy(base, "stripe_cache_size");
 181                 if (load_sys(fname, buf))
 182                         goto abort;
 183                 sra->cache_size = strtoul(buf, NULL, 0);
 184         }
 185         if (options & GET_MISMATCH) {
 186                 strcpy(base, "mismatch_cnt");
 187                 if (load_sys(fname, buf))
 188                         goto abort;
 189                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 190         }
 191         if (options & GET_SAFEMODE) {
 192                 int scale = 1;
 193                 int dot = 0;
 194                 unsigned i;
 195                 unsigned long msec;
 196                 size_t len;
 197
 198                 strcpy(base, "safe_mode_delay");
 199                 if (load_sys(fname, buf))
 200                         goto abort;
 201
 202                 /* remove a period, and count digits after it */
 203                 len = strlen(buf);
 204                 for (i = 0; i < len; i++) {
 205                         if (dot) {
 206                                 if (isdigit(buf[i])) {
 207                                         buf[i-1] = buf[i];
 208                                         scale *= 10;
 209                                 }
 210                                 buf[i] = 0;
 211                         } else if (buf[i] == '.') {
 212                                 dot=1;
 213                                 buf[i] = 0;
 214                         }
 215                 }
 216                 msec = strtoul(buf, NULL, 10);
 217                 msec = (msec * 1000) / scale;
 218                 sra->safe_mode_delay = msec;
 219         }
 220
 221         if (! (options & GET_DEVS))
 222                 return sra;
 223
 224         /* Get all the devices as well */
 225         *base = 0;
 226         dir = opendir(fname);
 227         if (!dir)
 228                 goto abort;
 229         sra->array.spare_disks = 0;
 230
 231         while ((de = readdir(dir)) != NULL) {
 232                 char *ep;
 233                 if (de->d_ino == 0 ||
 234                     strncmp(de->d_name, "dev-", 4) != 0)
 235                         continue;
 236                 strcpy(base, de->d_name);
 237                 dbase = base + strlen(base);
 238                 *dbase++ = '/';
 239
 240                 dev = malloc(sizeof(*dev));
 241                 if (!dev)
 242                         goto abort;
 243
 244                 /* Always get slot, major, minor */
 245                 strcpy(dbase, "slot");
 246                 if (load_sys(fname, buf)) {
 247                         /* hmm... unable to read 'slot' maybe the device
 248                          * is going away?
 249                          */
 250                         strcpy(dbase, "block");
 251                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 252                             errno != ENAMETOOLONG) {
 253                                 /* ...yup device is gone */
 254                                 free(dev);
 255                                 continue;
 256                         } else {
 257                                 /* slot is unreadable but 'block' link
 258                                  * still intact... something bad is happening
 259                                  * so abort
 260                                  */
 261                                 free(dev);
 262                                 goto abort;
 263                         }
 264
 265                 }
 266                 strcpy(dev->sys_name, de->d_name);
 267                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 268                 if (*ep) dev->disk.raid_disk = -1;
 269
 270                 strcpy(dbase, "block/dev");
 271                 if (load_sys(fname, buf)) {
 272                         /* assume this is a stale reference to a hot
 273                          * removed device
 274                          */
 275                         free(dev);
 276                         continue;
 277                 }
 278                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 279
 280                 /* special case check for block devices that can go 'offline' */
 281                 strcpy(dbase, "block/device/state");
 282                 if (load_sys(fname, buf) == 0 &&
 283                     strncmp(buf, "offline", 7) == 0) {
 284                         free(dev);
 285                         continue;
 286                 }
 287
 288                 /* finally add this disk to the array */
 289                 dev->next = sra->devs;
 290                 sra->devs = dev;
 291
 292                 if (options & GET_OFFSET) {
 293                         strcpy(dbase, "offset");
 294                         if (load_sys(fname, buf))
 295                                 goto abort;
 296                         dev->data_offset = strtoull(buf, NULL, 0);
 297                 }
 298                 if (options & GET_SIZE) {
 299                         strcpy(dbase, "size");
 300                         if (load_sys(fname, buf))
 301                                 goto abort;
 302                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 303                 }
 304                 if (options & GET_STATE) {
 305                         dev->disk.state = 0;
 306                         strcpy(dbase, "state");
 307                         if (load_sys(fname, buf))
 308                                 goto abort;
 309                         if (strstr(buf, "in_sync"))
 310                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 311                         if (strstr(buf, "faulty"))
 312                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 313                         if (dev->disk.state == 0)
 314                                 sra->array.spare_disks++;
 315                 }
 316                 if (options & GET_ERROR) {
 317                         strcpy(buf, "errors");
 318                         if (load_sys(fname, buf))
 319                                 goto abort;
 320                         dev->errors = strtoul(buf, NULL, 0);
 321                 }
 322         }
 323         closedir(dir);
 324         return sra;
 325
 326  abort:
 327         if (dir)
 328                 closedir(dir);
 329         sysfs_free(sra);
 330         return NULL;
 331 }
 332
 333 int sysfs_attr_match(const char *attr, const char *str)
 334 {
 335         /* See if attr, read from a sysfs file, matches
 336          * str.  They must either be the same, or attr can
 337          * have a trailing newline or comma
 338          */
 339         while (*attr && *str && *attr == *str) {
 340                 attr++;
 341                 str++;
 342         }
 343
 344         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 345                 return 0;
 346         return 1;
 347 }
 348
 349 int sysfs_match_word(const char *word, char **list)
 350 {
 351         int n;
 352         for (n=0; list[n]; n++)
 353                 if (sysfs_attr_match(word, list[n]))
 354                         break;
 355         return n;
 356 }
 357
 358 unsigned long long get_component_size(int fd)
 359 {
 360         /* Find out the component size of the array.
 361          * We cannot trust GET_ARRAY_INFO ioctl as it's
 362          * size field is only 32bits.
 363          * So look in /sys/block/mdXXX/md/component_size
 364          *
 365          * This returns in units of sectors.
 366          */
 367         struct stat stb;
 368         char fname[50];
 369         int n;
 370         if (fstat(fd, &stb)) return 0;
 371         if (major(stb.st_rdev) != (unsigned)get_mdp_major())
 372                 sprintf(fname, "/sys/block/md%d/md/component_size",
 373                         (int)minor(stb.st_rdev));
 374         else
 375                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 376                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 377         fd = open(fname, O_RDONLY);
 378         if (fd < 0)
 379                 return 0;
 380         n = read(fd, fname, sizeof(fname));
 381         close(fd);
 382         if (n == sizeof(fname))
 383                 return 0;
 384         fname[n] = 0;
 385         return strtoull(fname, NULL, 10) * 2;
 386 }
 387
 388 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 389                   char *name, char *val)
 390 {
 391         char fname[50];
 392         unsigned int n;
 393         int fd;
 394
 395         sprintf(fname, "/sys/block/%s/md/%s/%s",
 396                 sra->sys_name, dev?dev->sys_name:"", name);
 397         fd = open(fname, O_WRONLY);
 398         if (fd < 0)
 399                 return -1;
 400         n = write(fd, val, strlen(val));
 401         close(fd);
 402         if (n != strlen(val)) {
 403                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 404                         val, fname, strerror(errno));
 405                 return -1;
 406         }
 407         return 0;
 408 }
 409
 410 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 411                   char *name, unsigned long long val)
 412 {
 413         char valstr[50];
 414         sprintf(valstr, "%llu", val);
 415         return sysfs_set_str(sra, dev, name, valstr);
 416 }
 417
 418 int sysfs_uevent(struct mdinfo *sra, char *event)
 419 {
 420         char fname[50];
 421         int n;
 422         int fd;
 423
 424         sprintf(fname, "/sys/block/%s/uevent",
 425                 sra->sys_name);
 426         fd = open(fname, O_WRONLY);
 427         if (fd < 0)
 428                 return -1;
 429         n = write(fd, event, strlen(event));
 430         close(fd);
 431         if (n != (int)strlen(event)) {
 432                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 433                         event, fname, strerror(errno));
 434                 return -1;
 435         }
 436         return 0;
 437 }
 438
 439 int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
 440 {
 441         char fname[50];
 442         struct stat st;
 443
 444         sprintf(fname, "/sys/block/%s/md/%s/%s",
 445                 sra->sys_name, dev?dev->sys_name:"", name);
 446
 447         return stat(fname, &st) == 0;
 448 }
 449
 450 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
 451                        char *name)
 452 {
 453         char fname[50];
 454         int fd;
 455
 456         sprintf(fname, "/sys/block/%s/md/%s/%s",
 457                 sra->sys_name, dev?dev->sys_name:"", name);
 458         fd = open(fname, O_RDWR);
 459         if (fd < 0)
 460                 fd = open(fname, O_RDONLY);
 461         return fd;
 462 }
 463
 464 int sysfs_fd_get_ll(int fd, unsigned long long *val)
 465 {
 466         char buf[50];
 467         int n;
 468         char *ep;
 469
 470         lseek(fd, 0, 0);
 471         n = read(fd, buf, sizeof(buf));
 472         if (n <= 0)
 473                 return -2;
 474         buf[n] = 0;
 475         *val = strtoull(buf, &ep, 0);
 476         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 477                 return -1;
 478         return 0;
 479 }
 480
 481 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 482                        char *name, unsigned long long *val)
 483 {
 484         int n;
 485         int fd;
 486
 487         fd = sysfs_get_fd(sra, dev, name);
 488         if (fd < 0)
 489                 return -1;
 490         n = sysfs_fd_get_ll(fd, val);
 491         close(fd);
 492         return n;
 493 }
 494
 495 int sysfs_fd_get_str(int fd, char *val, int size)
 496 {
 497         int n;
 498
 499         lseek(fd, 0, 0);
 500         n = read(fd, val, size);
 501         if (n <= 0)
 502                 return -1;
 503         val[n] = 0;
 504         return n;
 505 }
 506
 507 int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
 508                        char *name, char *val, int size)
 509 {
 510         int n;
 511         int fd;
 512
 513         fd = sysfs_get_fd(sra, dev, name);
 514         if (fd < 0)
 515                 return -1;
 516         n = sysfs_fd_get_str(fd, val, size);
 517         close(fd);
 518         return n;
 519 }
 520
 521 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 522 {
 523         unsigned long sec;
 524         unsigned long msec;
 525         char delay[30];
 526
 527         sec = ms / 1000;
 528         msec = ms % 1000;
 529
 530         sprintf(delay, "%ld.%03ld\n", sec, msec);
 531         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 532         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 533 }
 534
 535 int sysfs_set_array(struct mdinfo *info, int vers)
 536 {
 537         int rv = 0;
 538         char ver[100];
 539         int raid_disks = info->array.raid_disks;
 540
 541         ver[0] = 0;
 542         if (info->array.major_version == -1 &&
 543             info->array.minor_version == -2) {
 544                 char buf[1024];
 545
 546                 strcat(strcpy(ver, "external:"), info->text_version);
 547
 548                 /* meta version might already be set if we are setting
 549                  * new geometry for a reshape.  In that case we don't
 550                  * want to over-write the 'readonly' flag that is
 551                  * stored in the metadata version.  So read the current
 552                  * version first, and preserve the flag
 553                  */
 554                 if (sysfs_get_str(info, NULL, "metadata_version",
 555                                   buf, 1024) > 0)
 556                         if (strlen(buf) >= 9 && buf[9] == '-')
 557                                 ver[9] = '-';
 558
 559                 if ((vers % 100) < 2 ||
 560                     sysfs_set_str(info, NULL, "metadata_version",
 561                                   ver) < 0) {
 562                         fprintf(stderr, Name ": This kernel does not "
 563                                 "support external metadata.\n");
 564                         return 1;
 565                 }
 566         }
 567         if (info->array.level < 0)
 568                 return 0; /* FIXME */
 569         rv |= sysfs_set_str(info, NULL, "level",
 570                             map_num(pers, info->array.level));
 571         if (info->reshape_active && info->delta_disks != UnSet)
 572                 raid_disks -= info->delta_disks;
 573         rv |= sysfs_set_num(info, NULL, "raid_disks", raid_disks);
 574         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 575         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 576         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 577         if (info->custom_array_size) {
 578                 int rc;
 579
 580                 rc = sysfs_set_num(info, NULL, "array_size",
 581                                    info->custom_array_size/2);
 582                 if (rc && errno == ENOENT) {
 583                         fprintf(stderr, Name ": This kernel does not "
 584                                 "have the md/array_size attribute, "
 585                                 "the array may be larger than expected\n");
 586                         rc = 0;
 587                 }
 588                 rv |= rc;
 589         }
 590
 591         if (info->array.level > 0)
 592                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 593
 594         if (info->reshape_active) {
 595                 rv |= sysfs_set_num(info, NULL, "reshape_position",
 596                                     info->reshape_progress);
 597                 rv |= sysfs_set_num(info, NULL, "chunk_size", info->new_chunk);
 598                 rv |= sysfs_set_num(info, NULL, "layout", info->new_layout);
 599                 rv |= sysfs_set_num(info, NULL, "raid_disks",
 600                                     info->array.raid_disks);
 601                 /* We don't set 'new_level' here.  That can only happen
 602                  * once the reshape completes.
 603                  */
 604         }
 605         return rv;
 606 }
 607
 608 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 609 {
 610         char dv[PATH_MAX];
 611         char nm[PATH_MAX];
 612         char *dname;
 613         int rv;
 614
 615         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 616         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 617         if (rv)
 618                 return rv;
 619
 620         memset(nm, 0, sizeof(nm));
 621         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 622         rv = readlink(dv, nm, sizeof(nm)-1);
 623         if (rv <= 0)
 624                 return -1;
 625         nm[rv] = '\0';
 626         dname = strrchr(nm, '/');
 627         if (dname) dname++;
 628         strcpy(sd->sys_name, "dev-");
 629         strcpy(sd->sys_name+4, dname);
 630
 631         /* test write to see if 'recovery_start' is available */
 632         if (resume && sd->recovery_start < MaxSector &&
 633             sysfs_set_num(sra, sd, "recovery_start", 0)) {
 634                 sysfs_set_str(sra, sd, "state", "remove");
 635                 return -1;
 636         }
 637
 638         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 639         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 640         if (sra->array.level != LEVEL_CONTAINER) {
 641                 if (sd->recovery_start == MaxSector)
 642                         /* This can correctly fail if array isn't started,
 643                          * yet, so just ignore status for now.
 644                          */
 645                         sysfs_set_str(sra, sd, "state", "insync");
 646                 if (sd->disk.raid_disk >= 0)
 647                         rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 648                 if (resume)
 649                         sysfs_set_num(sra, sd, "recovery_start", sd->recovery_start);
 650         }
 651         return rv;
 652 }
 653
 654 #if 0
 655 int sysfs_disk_to_sg(int fd)
 656 {
 657         /* from an open block device, try find and open its corresponding
 658          * scsi_generic interface
 659          */
 660         struct stat st;
 661         char path[256];
 662         char sg_path[256];
 663         char sg_major_minor[8];
 664         char *c;
 665         DIR *dir;
 666         struct dirent *de;
 667         int major, minor, rv;
 668
 669         if (fstat(fd, &st))
 670                 return -1;
 671
 672         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 673                  major(st.st_rdev), minor(st.st_rdev));
 674
 675         dir = opendir(path);
 676         if (!dir)
 677                 return -1;
 678
 679         de = readdir(dir);
 680         while (de) {
 681                 if (strncmp("scsi_generic:", de->d_name,
 682                             strlen("scsi_generic:")) == 0)
 683                         break;
 684                 de = readdir(dir);
 685         }
 686         closedir(dir);
 687
 688         if (!de)
 689                 return -1;
 690
 691         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 692         fd = open(sg_path, O_RDONLY);
 693         if (fd < 0)
 694                 return fd;
 695
 696         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 697         close(fd);
 698         if (rv < 0)
 699                 return -1;
 700         else
 701                 sg_major_minor[rv - 1] = '\0';
 702
 703         c = strchr(sg_major_minor, ':');
 704         *c = '\0';
 705         c++;
 706         major = strtol(sg_major_minor, NULL, 10);
 707         minor = strtol(c, NULL, 10);
 708         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 709                  (int) getpid(), major, minor);
 710         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 711                         fd = open(path, O_RDONLY);
 712                         unlink(path);
 713                         return fd;
 714         }
 715
 716         return -1;
 717 }
 718 #endif
 719
 720 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 721 {
 722         /* from an open block device, try to retrieve it scsi_id */
 723         struct stat st;
 724         char path[256];
 725         DIR *dir;
 726         struct dirent *de;
 727         int host, bus, target, lun;
 728
 729         if (fstat(fd, &st))
 730                 return 1;
 731
 732         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
 733                  major(st.st_rdev), minor(st.st_rdev));
 734
 735         dir = opendir(path);
 736         if (!dir)
 737                 return 1;
 738
 739         for (de = readdir(dir); de; de = readdir(dir)) {
 740                 int count;
 741
 742                 if (de->d_type != DT_DIR)
 743                         continue;
 744
 745                 count = sscanf(de->d_name, "%d:%d:%d:%d", &host, &bus, &target, &lun);
 746                 if (count == 4)
 747                         break;
 748         }
 749         closedir(dir);
 750
 751         if (!de)
 752                 return 1;
 753
 754         *id = (host << 24) | (bus << 16) | (target << 8) | (lun << 0);
 755         return 0;
 756 }
 757
 758
 759 int sysfs_unique_holder(int devnum, long rdev)
 760 {
 761         /* Check that devnum is a holder of rdev,
 762          * and is the only holder.
 763          * we should be locked against races by
 764          * an O_EXCL on devnum
 765          */
 766         DIR *dir;
 767         struct dirent *de;
 768         char dirname[100];
 769         char l;
 770         int found = 0;
 771         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 772                 major(rdev), minor(rdev));
 773         dir = opendir(dirname);
 774         errno = ENOENT;
 775         if (!dir)
 776                 return 0;
 777         l = strlen(dirname);
 778         while ((de = readdir(dir)) != NULL) {
 779                 char buf[10];
 780                 int n;
 781                 int mj, mn;
 782                 char c;
 783                 int fd;
 784
 785                 if (de->d_ino == 0)
 786                         continue;
 787                 if (de->d_name[0] == '.')
 788                         continue;
 789                 strcpy(dirname+l, "/");
 790                 strcat(dirname+l, de->d_name);
 791                 strcat(dirname+l, "/dev");
 792                 fd = open(dirname, O_RDONLY);
 793                 if (fd < 0) {
 794                         errno = ENOENT;
 795                         break;
 796                 }
 797                 n = read(fd, buf, sizeof(buf)-1);
 798                 close(fd);
 799                 buf[n] = 0;
 800                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 801                     c != '\n') {
 802                         errno = ENOENT;
 803                         break;
 804                 }
 805                 if (mj != MD_MAJOR)
 806                         mn = -1-(mn>>6);
 807
 808                 if (devnum != mn) {
 809                         errno = EEXIST;
 810                         break;
 811                 }
 812                 found = 1;
 813         }
 814         closedir(dir);
 815         if (de)
 816                 return 0;
 817         else
 818                 return found;
 819 }
 820
 821 int sysfs_freeze_array(struct mdinfo *sra)
 822 {
 823         /* Try to freeze resync/rebuild on this array/container.
 824          * Return -1 if the array is busy,
 825          * return -2 container cannot be frozen,
 826          * return 0 if this kernel doesn't support 'frozen'
 827          * return 1 if it worked.
 828          */
 829         char buf[20];
 830
 831         if (!sysfs_attribute_available(sra, NULL, "sync_action"))
 832                 return 1; /* no sync_action == frozen */
 833         if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
 834                 return 0;
 835         if (strcmp(buf, "idle\n") != 0 &&
 836             strcmp(buf, "frozen\n") != 0)
 837                 return -1;
 838         if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
 839                 return 0;
 840         return 1;
 841 }