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 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
  65         sprintf(fname, "/sys/block/%s/md/", devnum2devname(devnum));
  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, int devnum)
  78 {
  79         if (fd >= 0) {
  80                 struct stat stb;
  81                 mdu_version_t vers;
  82                 if (fstat(fd, &stb))
  83                         return;
  84                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  85                         return;
  86                 if (major(stb.st_rdev)==9)
  87                         sprintf(mdi->sys_name, "md%d", (int)minor(stb.st_rdev));
  88                 else
  89                         sprintf(mdi->sys_name, "md_d%d",
  90                                 (int)minor(stb.st_rdev)>>MdpMinorShift);
  91         } else {
  92                 if (devnum >= 0)
  93                         sprintf(mdi->sys_name, "md%d", devnum);
  94                 else
  95                         sprintf(mdi->sys_name, "md_d%d",
  96                                 -1-devnum);
  97         }
  98 }
  99
 100 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
 101 {
 102         /* Longest possible name in sysfs, mounted at /sys, is
 103          *  /sys/block/md_dXXX/md/dev-XXXXX/block/dev
 104          *  /sys/block/md_dXXX/md/metadata_version
 105          * which is about 41 characters.  50 should do for now
 106          */
 107         char fname[50];
 108         char buf[1024];
 109         char *base;
 110         char *dbase;
 111         struct mdinfo *sra;
 112         struct mdinfo *dev;
 113         DIR *dir = NULL;
 114         struct dirent *de;
 115
 116         sra = malloc(sizeof(*sra));
 117         if (sra == NULL)
 118                 return sra;
 119         memset(sra, 0, sizeof(*sra));
 120         sysfs_init(sra, fd, devnum);
 121
 122         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 123         base = fname + strlen(fname);
 124
 125         sra->devs = NULL;
 126         if (options & GET_VERSION) {
 127                 strcpy(base, "metadata_version");
 128                 if (load_sys(fname, buf))
 129                         goto abort;
 130                 if (strncmp(buf, "none", 4) == 0) {
 131                         sra->array.major_version =
 132                                 sra->array.minor_version = -1;
 133                         strcpy(sra->text_version, "");
 134                 } else if (strncmp(buf, "external:", 9) == 0) {
 135                         sra->array.major_version = -1;
 136                         sra->array.minor_version = -2;
 137                         strcpy(sra->text_version, buf+9);
 138                 } else {
 139                         sscanf(buf, "%d.%d",
 140                                &sra->array.major_version,
 141                                &sra->array.minor_version);
 142                         strcpy(sra->text_version, buf);
 143                 }
 144         }
 145         if (options & GET_LEVEL) {
 146                 strcpy(base, "level");
 147                 if (load_sys(fname, buf))
 148                         goto abort;
 149                 sra->array.level = map_name(pers, buf);
 150         }
 151         if (options & GET_LAYOUT) {
 152                 strcpy(base, "layout");
 153                 if (load_sys(fname, buf))
 154                         goto abort;
 155                 sra->array.layout = strtoul(buf, NULL, 0);
 156         }
 157         if (options & GET_DISKS) {
 158                 strcpy(base, "raid_disks");
 159                 if (load_sys(fname, buf))
 160                         goto abort;
 161                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 162         }
 163         if (options & GET_DEGRADED) {
 164                 strcpy(base, "degraded");
 165                 if (load_sys(fname, buf))
 166                         goto abort;
 167                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 168         }
 169         if (options & GET_COMPONENT) {
 170                 strcpy(base, "component_size");
 171                 if (load_sys(fname, buf))
 172                         goto abort;
 173                 sra->component_size = strtoull(buf, NULL, 0);
 174                 /* sysfs reports "K", but we want sectors */
 175                 sra->component_size *= 2;
 176         }
 177         if (options & GET_CHUNK) {
 178                 strcpy(base, "chunk_size");
 179                 if (load_sys(fname, buf))
 180                         goto abort;
 181                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 182         }
 183         if (options & GET_CACHE) {
 184                 strcpy(base, "stripe_cache_size");
 185                 if (load_sys(fname, buf))
 186                         goto abort;
 187                 sra->cache_size = strtoul(buf, NULL, 0);
 188         }
 189         if (options & GET_MISMATCH) {
 190                 strcpy(base, "mismatch_cnt");
 191                 if (load_sys(fname, buf))
 192                         goto abort;
 193                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 194         }
 195         if (options & GET_SAFEMODE) {
 196                 int scale = 1;
 197                 int dot = 0;
 198                 int i;
 199                 unsigned long msec;
 200                 size_t len;
 201
 202                 strcpy(base, "safe_mode_delay");
 203                 if (load_sys(fname, buf))
 204                         goto abort;
 205
 206                 /* remove a period, and count digits after it */
 207                 len = strlen(buf);
 208                 for (i = 0; i < len; i++) {
 209                         if (dot) {
 210                                 if (isdigit(buf[i])) {
 211                                         buf[i-1] = buf[i];
 212                                         scale *= 10;
 213                                 }
 214                                 buf[i] = 0;
 215                         } else if (buf[i] == '.') {
 216                                 dot=1;
 217                                 buf[i] = 0;
 218                         }
 219                 }
 220                 msec = strtoul(buf, NULL, 10);
 221                 msec = (msec * 1000) / scale;
 222                 sra->safe_mode_delay = msec;
 223         }
 224
 225         if (! (options & GET_DEVS))
 226                 return sra;
 227
 228         /* Get all the devices as well */
 229         *base = 0;
 230         dir = opendir(fname);
 231         if (!dir)
 232                 goto abort;
 233         sra->array.spare_disks = 0;
 234
 235         while ((de = readdir(dir)) != NULL) {
 236                 char *ep;
 237                 if (de->d_ino == 0 ||
 238                     strncmp(de->d_name, "dev-", 4) != 0)
 239                         continue;
 240                 strcpy(base, de->d_name);
 241                 dbase = base + strlen(base);
 242                 *dbase++ = '/';
 243
 244                 dev = malloc(sizeof(*dev));
 245                 if (!dev)
 246                         goto abort;
 247
 248                 /* Always get slot, major, minor */
 249                 strcpy(dbase, "slot");
 250                 if (load_sys(fname, buf)) {
 251                         /* hmm... unable to read 'slot' maybe the device
 252                          * is going away?
 253                          */
 254                         strcpy(dbase, "block");
 255                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 256                             errno != ENAMETOOLONG) {
 257                                 /* ...yup device is gone */
 258                                 free(dev);
 259                                 continue;
 260                         } else {
 261                                 /* slot is unreadable but 'block' link
 262                                  * still intact... something bad is happening
 263                                  * so abort
 264                                  */
 265                                 free(dev);
 266                                 goto abort;
 267                         }
 268
 269                 }
 270                 dev->next = sra->devs;
 271                 sra->devs = dev;
 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                         goto abort;
 280                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 281
 282                 if (options & GET_OFFSET) {
 283                         strcpy(dbase, "offset");
 284                         if (load_sys(fname, buf))
 285                                 goto abort;
 286                         dev->data_offset = strtoull(buf, NULL, 0);
 287                 }
 288                 if (options & GET_SIZE) {
 289                         strcpy(dbase, "size");
 290                         if (load_sys(fname, buf))
 291                                 goto abort;
 292                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 293                 }
 294                 if (options & GET_STATE) {
 295                         dev->disk.state = 0;
 296                         strcpy(dbase, "state");
 297                         if (load_sys(fname, buf))
 298                                 goto abort;
 299                         if (strstr(buf, "in_sync"))
 300                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 301                         if (strstr(buf, "faulty"))
 302                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 303                         if (dev->disk.state == 0)
 304                                 sra->array.spare_disks++;
 305                 }
 306                 if (options & GET_ERROR) {
 307                         strcpy(buf, "errors");
 308                         if (load_sys(fname, buf))
 309                                 goto abort;
 310                         dev->errors = strtoul(buf, NULL, 0);
 311                 }
 312         }
 313         closedir(dir);
 314         return sra;
 315
 316  abort:
 317         if (dir)
 318                 closedir(dir);
 319         sysfs_free(sra);
 320         return NULL;
 321 }
 322
 323 int sysfs_attr_match(const char *attr, const char *str)
 324 {
 325         /* See if attr, read from a sysfs file, matches
 326          * str.  They must either be the same, or attr can
 327          * have a trailing newline or comma
 328          */
 329         while (*attr && *str && *attr == *str) {
 330                 attr++;
 331                 str++;
 332         }
 333
 334         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 335                 return 0;
 336         return 1;
 337 }
 338
 339 int sysfs_match_word(const char *word, char **list)
 340 {
 341         int n;
 342         for (n=0; list[n]; n++)
 343                 if (sysfs_attr_match(word, list[n]))
 344                         break;
 345         return n;
 346 }
 347
 348 unsigned long long get_component_size(int fd)
 349 {
 350         /* Find out the component size of the array.
 351          * We cannot trust GET_ARRAY_INFO ioctl as it's
 352          * size field is only 32bits.
 353          * So look in /sys/block/mdXXX/md/component_size
 354          *
 355          * This returns in units of sectors.
 356          */
 357         struct stat stb;
 358         char fname[50];
 359         int n;
 360         if (fstat(fd, &stb)) return 0;
 361         if (major(stb.st_rdev) == 9)
 362                 sprintf(fname, "/sys/block/md%d/md/component_size",
 363                         (int)minor(stb.st_rdev));
 364         else
 365                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 366                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 367         fd = open(fname, O_RDONLY);
 368         if (fd < 0)
 369                 return 0;
 370         n = read(fd, fname, sizeof(fname));
 371         close(fd);
 372         if (n == sizeof(fname))
 373                 return 0;
 374         fname[n] = 0;
 375         return strtoull(fname, NULL, 10) * 2;
 376 }
 377
 378 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 379                   char *name, char *val)
 380 {
 381         char fname[50];
 382         int n;
 383         int fd;
 384
 385         sprintf(fname, "/sys/block/%s/md/%s/%s",
 386                 sra->sys_name, dev?dev->sys_name:"", name);
 387         fd = open(fname, O_WRONLY);
 388         if (fd < 0)
 389                 return -1;
 390         n = write(fd, val, strlen(val));
 391         close(fd);
 392         if (n != strlen(val))
 393                 return -1;
 394         return 0;
 395 }
 396
 397 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 398                   char *name, unsigned long long val)
 399 {
 400         char valstr[50];
 401         sprintf(valstr, "%llu", val);
 402         return sysfs_set_str(sra, dev, name, valstr);
 403 }
 404
 405 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 406                        char *name, unsigned long long *val)
 407 {
 408         char fname[50];
 409         char buf[50];
 410         int n;
 411         int fd;
 412         char *ep;
 413         sprintf(fname, "/sys/block/%s/md/%s/%s",
 414                 sra->sys_name, dev?dev->sys_name:"", name);
 415         fd = open(fname, O_RDONLY);
 416         if (fd < 0)
 417                 return -1;
 418         n = read(fd, buf, sizeof(buf));
 419         close(fd);
 420         if (n <= 0)
 421                 return -1;
 422         buf[n] = 0;
 423         *val = strtoull(buf, &ep, 0);
 424         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 425                 return -1;
 426         return 0;
 427 }
 428
 429 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 430 {
 431         unsigned long sec;
 432         unsigned long msec;
 433         char delay[30];
 434
 435         sec = ms / 1000;
 436         msec = ms - (sec * 1000);
 437
 438         sprintf(delay, "%ld.%ld", sec, msec);
 439         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 440 }
 441
 442 int sysfs_set_array(struct mdinfo *info, int vers)
 443 {
 444         int rv = 0;
 445         char ver[100];
 446
 447         ver[0] = 0;
 448         if (info->array.major_version == -1 &&
 449             info->array.minor_version == -2) {
 450                 strcat(strcpy(ver, "external:"), info->text_version);
 451
 452                 if ((vers % 100) < 2 ||
 453                     sysfs_set_str(info, NULL, "metadata_version",
 454                                   ver) < 0) {
 455                         fprintf(stderr, Name ": This kernel does not "
 456                                 "support external metadata.\n");
 457                         return 1;
 458                 }
 459         }
 460         if (info->array.level < 0)
 461                 return 0; /* FIXME */
 462         rv |= sysfs_set_str(info, NULL, "level",
 463                             map_num(pers, info->array.level));
 464         rv |= sysfs_set_num(info, NULL, "raid_disks", info->array.raid_disks);
 465         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 466         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 467         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 468         if (info->array.level > 0)
 469                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 470         return rv;
 471 }
 472
 473 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd)
 474 {
 475         char dv[100];
 476         char nm[100];
 477         char *dname;
 478         int rv;
 479
 480         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 481         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 482         if (rv)
 483                 return rv;
 484
 485         memset(nm, 0, sizeof(nm));
 486         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 487         rv = readlink(dv, nm, sizeof(nm));
 488         if (rv <= 0)
 489                 return -1;
 490         nm[rv] = '\0';
 491         dname = strrchr(nm, '/');
 492         if (dname) dname++;
 493         strcpy(sd->sys_name, "dev-");
 494         strcpy(sd->sys_name+4, dname);
 495
 496         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 497         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 498         if (sra->array.level != LEVEL_CONTAINER) {
 499                 rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 500 //              rv |= sysfs_set_str(sra, sd, "state", "in_sync");
 501         }
 502         return rv;
 503 }
 504
 505 #if 0
 506 int sysfs_disk_to_sg(int fd)
 507 {
 508         /* from an open block device, try find and open its corresponding
 509          * scsi_generic interface
 510          */
 511         struct stat st;
 512         char path[256];
 513         char sg_path[256];
 514         char sg_major_minor[8];
 515         char *c;
 516         DIR *dir;
 517         struct dirent *de;
 518         int major, minor, rv;
 519
 520         if (fstat(fd, &st))
 521                 return -1;
 522
 523         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 524                  major(st.st_rdev), minor(st.st_rdev));
 525
 526         dir = opendir(path);
 527         if (!dir)
 528                 return -1;
 529
 530         de = readdir(dir);
 531         while (de) {
 532                 if (strncmp("scsi_generic:", de->d_name,
 533                             strlen("scsi_generic:")) == 0)
 534                         break;
 535                 de = readdir(dir);
 536         }
 537         closedir(dir);
 538
 539         if (!de)
 540                 return -1;
 541
 542         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 543         fd = open(sg_path, O_RDONLY);
 544         if (fd < 0)
 545                 return fd;
 546
 547         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 548         close(fd);
 549         if (rv < 0)
 550                 return -1;
 551         else
 552                 sg_major_minor[rv - 1] = '\0';
 553
 554         c = strchr(sg_major_minor, ':');
 555         *c = '\0';
 556         c++;
 557         major = strtol(sg_major_minor, NULL, 10);
 558         minor = strtol(c, NULL, 10);
 559         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 560                  (int) getpid(), major, minor);
 561         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 562                         fd = open(path, O_RDONLY);
 563                         unlink(path);
 564                         return fd;
 565         }
 566
 567         return -1;
 568 }
 569 #endif
 570
 571 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 572 {
 573         /* from an open block device, try to retrieve it scsi_id */
 574         struct stat st;
 575         char path[256];
 576         char *c1, *c2;
 577         DIR *dir;
 578         struct dirent *de;
 579
 580         if (fstat(fd, &st))
 581                 return 1;
 582
 583         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 584                  major(st.st_rdev), minor(st.st_rdev));
 585
 586         dir = opendir(path);
 587         if (!dir)
 588                 return 1;
 589
 590         de = readdir(dir);
 591         while (de) {
 592                 if (strncmp("scsi_disk:", de->d_name,
 593                             strlen("scsi_disk:")) == 0)
 594                         break;
 595                 de = readdir(dir);
 596         }
 597         closedir(dir);
 598
 599         if (!de)
 600                 return 1;
 601
 602         c1 = strchr(de->d_name, ':');
 603         c1++;
 604         c2 = strchr(c1, ':');
 605         *c2 = '\0';
 606         *id = strtol(c1, NULL, 10) << 24; /* host */
 607         c1 = c2 + 1;
 608         c2 = strchr(c1, ':');
 609         *c2 = '\0';
 610         *id |= strtol(c1, NULL, 10) << 16; /* channel */
 611         c1 = c2 + 1;
 612         c2 = strchr(c1, ':');
 613         *c2 = '\0';
 614         *id |= strtol(c1, NULL, 10) << 8; /* lun */
 615         c1 = c2 + 1;
 616         *id |= strtol(c1, NULL, 10); /* id */
 617
 618         return 0;
 619 }
 620
 621
 622 int sysfs_unique_holder(int devnum, long rdev)
 623 {
 624         /* Check that devnum is a holder of rdev,
 625          * and is the only holder.
 626          * we should be locked against races by
 627          * an O_EXCL on devnum
 628          */
 629         DIR *dir;
 630         struct dirent *de;
 631         char dirname[100];
 632         char l;
 633         int found = 0;
 634         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 635                 major(rdev), minor(rdev));
 636         dir = opendir(dirname);
 637         errno = ENOENT;
 638         if (!dir)
 639                 return 0;
 640         l = strlen(dirname);
 641         while ((de = readdir(dir)) != NULL) {
 642                 char buf[10];
 643                 int n;
 644                 int mj, mn;
 645                 char c;
 646                 int fd;
 647
 648                 if (de->d_ino == 0)
 649                         continue;
 650                 if (de->d_name[0] == '.')
 651                         continue;
 652                 strcpy(dirname+l, "/");
 653                 strcat(dirname+l, de->d_name);
 654                 strcat(dirname+l, "/dev");
 655                 fd = open(dirname, O_RDONLY);
 656                 if (fd < 0) {
 657                         errno = ENOENT;
 658                         break;
 659                 }
 660                 n = read(fd, buf, sizeof(buf)-1);
 661                 close(fd);
 662                 buf[n] = 0;
 663                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 664                     c != '\n') {
 665                         errno = ENOENT;
 666                         break;
 667                 }
 668                 if (mj != MD_MAJOR)
 669                         mn = -1-(mn>>6);
 670
 671                 if (devnum != mn) {
 672                         errno = EEXIST;
 673                         break;
 674                 }
 675                 found = 1;
 676         }
 677         closedir(dir);
 678         if (de)
 679                 return 0;
 680         else
 681                 return found;
 682 }