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         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         if (fd >= 0) {
  85                 struct stat stb;
  86                 mdu_version_t vers;
  87                 if (fstat(fd, &stb))
  88                         return;
  89                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  90                         return;
  91                 if (major(stb.st_rdev)==9)
  92                         sprintf(mdi->sys_name, "md%d", (int)minor(stb.st_rdev));
  93                 else
  94                         sprintf(mdi->sys_name, "md_d%d",
  95                                 (int)minor(stb.st_rdev)>>MdpMinorShift);
  96         } else {
  97                 if (devnum >= 0)
  98                         sprintf(mdi->sys_name, "md%d", devnum);
  99                 else
 100                         sprintf(mdi->sys_name, "md_d%d",
 101                                 -1-devnum);
 102         }
 103 }
 104
 105 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
 106 {
 107         /* Longest possible name in sysfs, mounted at /sys, is
 108          *  /sys/block/md_dXXX/md/dev-XXXXX/block/dev
 109          *  /sys/block/md_dXXX/md/metadata_version
 110          * which is about 41 characters.  50 should do for now
 111          */
 112         char fname[50];
 113         char buf[1024];
 114         char *base;
 115         char *dbase;
 116         struct mdinfo *sra;
 117         struct mdinfo *dev;
 118         DIR *dir = NULL;
 119         struct dirent *de;
 120
 121         sra = malloc(sizeof(*sra));
 122         if (sra == NULL)
 123                 return sra;
 124         memset(sra, 0, sizeof(*sra));
 125         sysfs_init(sra, fd, devnum);
 126
 127         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 128         base = fname + strlen(fname);
 129
 130         sra->devs = NULL;
 131         if (options & GET_VERSION) {
 132                 strcpy(base, "metadata_version");
 133                 if (load_sys(fname, buf))
 134                         goto abort;
 135                 if (strncmp(buf, "none", 4) == 0) {
 136                         sra->array.major_version =
 137                                 sra->array.minor_version = -1;
 138                         strcpy(sra->text_version, "");
 139                 } else if (strncmp(buf, "external:", 9) == 0) {
 140                         sra->array.major_version = -1;
 141                         sra->array.minor_version = -2;
 142                         strcpy(sra->text_version, buf+9);
 143                 } else {
 144                         sscanf(buf, "%d.%d",
 145                                &sra->array.major_version,
 146                                &sra->array.minor_version);
 147                         strcpy(sra->text_version, buf);
 148                 }
 149         }
 150         if (options & GET_LEVEL) {
 151                 strcpy(base, "level");
 152                 if (load_sys(fname, buf))
 153                         goto abort;
 154                 sra->array.level = map_name(pers, buf);
 155         }
 156         if (options & GET_LAYOUT) {
 157                 strcpy(base, "layout");
 158                 if (load_sys(fname, buf))
 159                         goto abort;
 160                 sra->array.layout = strtoul(buf, NULL, 0);
 161         }
 162         if (options & GET_DISKS) {
 163                 strcpy(base, "raid_disks");
 164                 if (load_sys(fname, buf))
 165                         goto abort;
 166                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 167         }
 168         if (options & GET_DEGRADED) {
 169                 strcpy(base, "degraded");
 170                 if (load_sys(fname, buf))
 171                         goto abort;
 172                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 173         }
 174         if (options & GET_COMPONENT) {
 175                 strcpy(base, "component_size");
 176                 if (load_sys(fname, buf))
 177                         goto abort;
 178                 sra->component_size = strtoull(buf, NULL, 0);
 179                 /* sysfs reports "K", but we want sectors */
 180                 sra->component_size *= 2;
 181         }
 182         if (options & GET_CHUNK) {
 183                 strcpy(base, "chunk_size");
 184                 if (load_sys(fname, buf))
 185                         goto abort;
 186                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 187         }
 188         if (options & GET_CACHE) {
 189                 strcpy(base, "stripe_cache_size");
 190                 if (load_sys(fname, buf))
 191                         goto abort;
 192                 sra->cache_size = strtoul(buf, NULL, 0);
 193         }
 194         if (options & GET_MISMATCH) {
 195                 strcpy(base, "mismatch_cnt");
 196                 if (load_sys(fname, buf))
 197                         goto abort;
 198                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 199         }
 200         if (options & GET_SAFEMODE) {
 201                 int scale = 1;
 202                 int dot = 0;
 203                 int i;
 204                 unsigned long msec;
 205                 size_t len;
 206
 207                 strcpy(base, "safe_mode_delay");
 208                 if (load_sys(fname, buf))
 209                         goto abort;
 210
 211                 /* remove a period, and count digits after it */
 212                 len = strlen(buf);
 213                 for (i = 0; i < len; i++) {
 214                         if (dot) {
 215                                 if (isdigit(buf[i])) {
 216                                         buf[i-1] = buf[i];
 217                                         scale *= 10;
 218                                 }
 219                                 buf[i] = 0;
 220                         } else if (buf[i] == '.') {
 221                                 dot=1;
 222                                 buf[i] = 0;
 223                         }
 224                 }
 225                 msec = strtoul(buf, NULL, 10);
 226                 msec = (msec * 1000) / scale;
 227                 sra->safe_mode_delay = msec;
 228         }
 229
 230         if (! (options & GET_DEVS))
 231                 return sra;
 232
 233         /* Get all the devices as well */
 234         *base = 0;
 235         dir = opendir(fname);
 236         if (!dir)
 237                 goto abort;
 238         sra->array.spare_disks = 0;
 239
 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 = malloc(sizeof(*dev));
 250                 if (!dev)
 251                         goto abort;
 252
 253                 /* Always get slot, major, minor */
 254                 strcpy(dbase, "slot");
 255                 if (load_sys(fname, buf)) {
 256                         /* hmm... unable to read 'slot' maybe the device
 257                          * is going away?
 258                          */
 259                         strcpy(dbase, "block");
 260                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 261                             errno != ENAMETOOLONG) {
 262                                 /* ...yup device is gone */
 263                                 free(dev);
 264                                 continue;
 265                         } else {
 266                                 /* slot is unreadable but 'block' link
 267                                  * still intact... something bad is happening
 268                                  * so abort
 269                                  */
 270                                 free(dev);
 271                                 goto abort;
 272                         }
 273
 274                 }
 275                 dev->next = sra->devs;
 276                 sra->devs = dev;
 277
 278                 strcpy(dev->sys_name, de->d_name);
 279                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 280                 if (*ep) dev->disk.raid_disk = -1;
 281
 282                 strcpy(dbase, "block/dev");
 283                 if (load_sys(fname, buf))
 284                         goto abort;
 285                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 286
 287                 if (options & GET_OFFSET) {
 288                         strcpy(dbase, "offset");
 289                         if (load_sys(fname, buf))
 290                                 goto abort;
 291                         dev->data_offset = strtoull(buf, NULL, 0);
 292                 }
 293                 if (options & GET_SIZE) {
 294                         strcpy(dbase, "size");
 295                         if (load_sys(fname, buf))
 296                                 goto abort;
 297                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 298                 }
 299                 if (options & GET_STATE) {
 300                         dev->disk.state = 0;
 301                         strcpy(dbase, "state");
 302                         if (load_sys(fname, buf))
 303                                 goto abort;
 304                         if (strstr(buf, "in_sync"))
 305                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 306                         if (strstr(buf, "faulty"))
 307                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 308                         if (dev->disk.state == 0)
 309                                 sra->array.spare_disks++;
 310                 }
 311                 if (options & GET_ERROR) {
 312                         strcpy(buf, "errors");
 313                         if (load_sys(fname, buf))
 314                                 goto abort;
 315                         dev->errors = strtoul(buf, NULL, 0);
 316                 }
 317         }
 318         closedir(dir);
 319         return sra;
 320
 321  abort:
 322         if (dir)
 323                 closedir(dir);
 324         sysfs_free(sra);
 325         return NULL;
 326 }
 327
 328 int sysfs_attr_match(const char *attr, const char *str)
 329 {
 330         /* See if attr, read from a sysfs file, matches
 331          * str.  They must either be the same, or attr can
 332          * have a trailing newline or comma
 333          */
 334         while (*attr && *str && *attr == *str) {
 335                 attr++;
 336                 str++;
 337         }
 338
 339         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 340                 return 0;
 341         return 1;
 342 }
 343
 344 int sysfs_match_word(const char *word, char **list)
 345 {
 346         int n;
 347         for (n=0; list[n]; n++)
 348                 if (sysfs_attr_match(word, list[n]))
 349                         break;
 350         return n;
 351 }
 352
 353 unsigned long long get_component_size(int fd)
 354 {
 355         /* Find out the component size of the array.
 356          * We cannot trust GET_ARRAY_INFO ioctl as it's
 357          * size field is only 32bits.
 358          * So look in /sys/block/mdXXX/md/component_size
 359          *
 360          * This returns in units of sectors.
 361          */
 362         struct stat stb;
 363         char fname[50];
 364         int n;
 365         if (fstat(fd, &stb)) return 0;
 366         if (major(stb.st_rdev) == 9)
 367                 sprintf(fname, "/sys/block/md%d/md/component_size",
 368                         (int)minor(stb.st_rdev));
 369         else
 370                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 371                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 372         fd = open(fname, O_RDONLY);
 373         if (fd < 0)
 374                 return 0;
 375         n = read(fd, fname, sizeof(fname));
 376         close(fd);
 377         if (n == sizeof(fname))
 378                 return 0;
 379         fname[n] = 0;
 380         return strtoull(fname, NULL, 10) * 2;
 381 }
 382
 383 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 384                   char *name, char *val)
 385 {
 386         char fname[50];
 387         int n;
 388         int fd;
 389
 390         sprintf(fname, "/sys/block/%s/md/%s/%s",
 391                 sra->sys_name, dev?dev->sys_name:"", name);
 392         fd = open(fname, O_WRONLY);
 393         if (fd < 0)
 394                 return -1;
 395         n = write(fd, val, strlen(val));
 396         close(fd);
 397         if (n != strlen(val)) {
 398                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 399                         val, fname, strerror(errno));
 400                 return -1;
 401         }
 402         return 0;
 403 }
 404
 405 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 406                   char *name, unsigned long long val)
 407 {
 408         char valstr[50];
 409         sprintf(valstr, "%llu", val);
 410         return sysfs_set_str(sra, dev, name, valstr);
 411 }
 412
 413 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 414                        char *name, unsigned long long *val)
 415 {
 416         char fname[50];
 417         char buf[50];
 418         int n;
 419         int fd;
 420         char *ep;
 421         sprintf(fname, "/sys/block/%s/md/%s/%s",
 422                 sra->sys_name, dev?dev->sys_name:"", name);
 423         fd = open(fname, O_RDONLY);
 424         if (fd < 0)
 425                 return -1;
 426         n = read(fd, buf, sizeof(buf));
 427         close(fd);
 428         if (n <= 0)
 429                 return -1;
 430         buf[n] = 0;
 431         *val = strtoull(buf, &ep, 0);
 432         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 433                 return -1;
 434         return 0;
 435 }
 436
 437 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 438 {
 439         unsigned long sec;
 440         unsigned long msec;
 441         char delay[30];
 442
 443         sec = ms / 1000;
 444         msec = ms % 1000;
 445
 446         sprintf(delay, "%ld.%03ld\n", sec, msec);
 447         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 448         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 449 }
 450
 451 int sysfs_set_array(struct mdinfo *info, int vers)
 452 {
 453         int rv = 0;
 454         char ver[100];
 455
 456         ver[0] = 0;
 457         if (info->array.major_version == -1 &&
 458             info->array.minor_version == -2) {
 459                 strcat(strcpy(ver, "external:"), info->text_version);
 460
 461                 if ((vers % 100) < 2 ||
 462                     sysfs_set_str(info, NULL, "metadata_version",
 463                                   ver) < 0) {
 464                         fprintf(stderr, Name ": This kernel does not "
 465                                 "support external metadata.\n");
 466                         return 1;
 467                 }
 468         }
 469         if (info->array.level < 0)
 470                 return 0; /* FIXME */
 471         rv |= sysfs_set_str(info, NULL, "level",
 472                             map_num(pers, info->array.level));
 473         rv |= sysfs_set_num(info, NULL, "raid_disks", info->array.raid_disks);
 474         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 475         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 476         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 477         if (info->array.level > 0)
 478                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 479         return rv;
 480 }
 481
 482 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd)
 483 {
 484         char dv[100];
 485         char nm[100];
 486         char *dname;
 487         int rv;
 488
 489         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 490         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 491         if (rv)
 492                 return rv;
 493
 494         memset(nm, 0, sizeof(nm));
 495         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 496         rv = readlink(dv, nm, sizeof(nm));
 497         if (rv <= 0)
 498                 return -1;
 499         nm[rv] = '\0';
 500         dname = strrchr(nm, '/');
 501         if (dname) dname++;
 502         strcpy(sd->sys_name, "dev-");
 503         strcpy(sd->sys_name+4, dname);
 504
 505         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 506         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 507         if (sra->array.level != LEVEL_CONTAINER) {
 508                 rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 509 //              rv |= sysfs_set_str(sra, sd, "state", "in_sync");
 510         }
 511         return rv;
 512 }
 513
 514 #if 0
 515 int sysfs_disk_to_sg(int fd)
 516 {
 517         /* from an open block device, try find and open its corresponding
 518          * scsi_generic interface
 519          */
 520         struct stat st;
 521         char path[256];
 522         char sg_path[256];
 523         char sg_major_minor[8];
 524         char *c;
 525         DIR *dir;
 526         struct dirent *de;
 527         int major, minor, rv;
 528
 529         if (fstat(fd, &st))
 530                 return -1;
 531
 532         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 533                  major(st.st_rdev), minor(st.st_rdev));
 534
 535         dir = opendir(path);
 536         if (!dir)
 537                 return -1;
 538
 539         de = readdir(dir);
 540         while (de) {
 541                 if (strncmp("scsi_generic:", de->d_name,
 542                             strlen("scsi_generic:")) == 0)
 543                         break;
 544                 de = readdir(dir);
 545         }
 546         closedir(dir);
 547
 548         if (!de)
 549                 return -1;
 550
 551         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 552         fd = open(sg_path, O_RDONLY);
 553         if (fd < 0)
 554                 return fd;
 555
 556         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 557         close(fd);
 558         if (rv < 0)
 559                 return -1;
 560         else
 561                 sg_major_minor[rv - 1] = '\0';
 562
 563         c = strchr(sg_major_minor, ':');
 564         *c = '\0';
 565         c++;
 566         major = strtol(sg_major_minor, NULL, 10);
 567         minor = strtol(c, NULL, 10);
 568         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 569                  (int) getpid(), major, minor);
 570         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 571                         fd = open(path, O_RDONLY);
 572                         unlink(path);
 573                         return fd;
 574         }
 575
 576         return -1;
 577 }
 578 #endif
 579
 580 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 581 {
 582         /* from an open block device, try to retrieve it scsi_id */
 583         struct stat st;
 584         char path[256];
 585         char *c1, *c2;
 586         DIR *dir;
 587         struct dirent *de;
 588
 589         if (fstat(fd, &st))
 590                 return 1;
 591
 592         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 593                  major(st.st_rdev), minor(st.st_rdev));
 594
 595         dir = opendir(path);
 596         if (!dir)
 597                 return 1;
 598
 599         de = readdir(dir);
 600         while (de) {
 601                 if (strncmp("scsi_disk:", de->d_name,
 602                             strlen("scsi_disk:")) == 0)
 603                         break;
 604                 de = readdir(dir);
 605         }
 606         closedir(dir);
 607
 608         if (!de)
 609                 return 1;
 610
 611         c1 = strchr(de->d_name, ':');
 612         c1++;
 613         c2 = strchr(c1, ':');
 614         *c2 = '\0';
 615         *id = strtol(c1, NULL, 10) << 24; /* host */
 616         c1 = c2 + 1;
 617         c2 = strchr(c1, ':');
 618         *c2 = '\0';
 619         *id |= strtol(c1, NULL, 10) << 16; /* channel */
 620         c1 = c2 + 1;
 621         c2 = strchr(c1, ':');
 622         *c2 = '\0';
 623         *id |= strtol(c1, NULL, 10) << 8; /* lun */
 624         c1 = c2 + 1;
 625         *id |= strtol(c1, NULL, 10); /* id */
 626
 627         return 0;
 628 }
 629
 630
 631 int sysfs_unique_holder(int devnum, long rdev)
 632 {
 633         /* Check that devnum is a holder of rdev,
 634          * and is the only holder.
 635          * we should be locked against races by
 636          * an O_EXCL on devnum
 637          */
 638         DIR *dir;
 639         struct dirent *de;
 640         char dirname[100];
 641         char l;
 642         int found = 0;
 643         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 644                 major(rdev), minor(rdev));
 645         dir = opendir(dirname);
 646         errno = ENOENT;
 647         if (!dir)
 648                 return 0;
 649         l = strlen(dirname);
 650         while ((de = readdir(dir)) != NULL) {
 651                 char buf[10];
 652                 int n;
 653                 int mj, mn;
 654                 char c;
 655                 int fd;
 656
 657                 if (de->d_ino == 0)
 658                         continue;
 659                 if (de->d_name[0] == '.')
 660                         continue;
 661                 strcpy(dirname+l, "/");
 662                 strcat(dirname+l, de->d_name);
 663                 strcat(dirname+l, "/dev");
 664                 fd = open(dirname, O_RDONLY);
 665                 if (fd < 0) {
 666                         errno = ENOENT;
 667                         break;
 668                 }
 669                 n = read(fd, buf, sizeof(buf)-1);
 670                 close(fd);
 671                 buf[n] = 0;
 672                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 673                     c != '\n') {
 674                         errno = ENOENT;
 675                         break;
 676                 }
 677                 if (mj != MD_MAJOR)
 678                         mn = -1-(mn>>6);
 679
 680                 if (devnum != mn) {
 681                         errno = EEXIST;
 682                         break;
 683                 }
 684                 found = 1;
 685         }
 686         closedir(dir);
 687         if (de)
 688                 return 0;
 689         else
 690                 return found;
 691 }