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
  29 int load_sys(char *path, char *buf)
  30 {
  31         int fd = open(path, O_RDONLY);
  32         int n;
  33         if (fd < 0)
  34                 return -1;
  35         n = read(fd, buf, 1024);
  36         close(fd);
  37         if (n <0 || n >= 1024)
  38                 return -1;
  39         buf[n] = 0;
  40         if (buf[n-1] == '\n')
  41                 buf[n-1] = 0;
  42         return 0;
  43 }
  44
  45 void sysfs_free(struct mdinfo *sra)
  46 {
  47         while (sra) {
  48                 struct mdinfo *sra2 = sra->next;
  49                 while (sra->devs) {
  50                         struct mdinfo *d = sra->devs;
  51                         sra->devs = d->next;
  52                         free(d);
  53                 }
  54                 free(sra);
  55                 sra = sra2;
  56         }
  57 }
  58
  59 int sysfs_open(int devnum, char *devname, char *attr)
  60 {
  61         char fname[50];
  62         int fd;
  63
  64         sprintf(fname, "/sys/block/%s/md/", devnum2devname(devnum));
  65         if (devname) {
  66                 strcat(fname, devname);
  67                 strcat(fname, "/");
  68         }
  69         strcat(fname, attr);
  70         fd = open(fname, O_RDWR);
  71         if (fd < 0 && errno == EACCES)
  72                 fd = open(fname, O_RDONLY);
  73         return fd;
  74 }
  75
  76 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
  77 {
  78         /* Longest possible name in sysfs, mounted at /sys, is
  79          *  /sys/block/md_dXXX/md/dev-XXXXX/block/dev
  80          *  /sys/block/md_dXXX/md/metadata_version
  81          * which is about 41 characters.  50 should do for now
  82          */
  83         char fname[50];
  84         char buf[1024];
  85         char *base;
  86         char *dbase;
  87         struct mdinfo *sra;
  88         struct mdinfo *dev;
  89         DIR *dir = NULL;
  90         struct dirent *de;
  91
  92         sra = malloc(sizeof(*sra));
  93         if (sra == NULL)
  94                 return sra;
  95         sra->next = NULL;
  96
  97         if (fd >= 0) {
  98                 struct stat stb;
  99                 mdu_version_t vers;
 100                 if (fstat(fd, &stb)) return NULL;
 101                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
 102                         return NULL;
 103                 if (major(stb.st_rdev)==9)
 104                         sprintf(sra->sys_name, "md%d", (int)minor(stb.st_rdev));
 105                 else
 106                         sprintf(sra->sys_name, "md_d%d",
 107                                 (int)minor(stb.st_rdev)>>MdpMinorShift);
 108         } else {
 109                 if (devnum >= 0)
 110                         sprintf(sra->sys_name, "md%d", devnum);
 111                 else
 112                         sprintf(sra->sys_name, "md_d%d",
 113                                 -1-devnum);
 114         }
 115         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 116         base = fname + strlen(fname);
 117
 118         sra->devs = NULL;
 119         if (options & GET_VERSION) {
 120                 strcpy(base, "metadata_version");
 121                 if (load_sys(fname, buf))
 122                         goto abort;
 123                 if (strncmp(buf, "none", 4) == 0) {
 124                         sra->array.major_version =
 125                                 sra->array.minor_version = -1;
 126                         strcpy(sra->text_version, "");
 127                 } else if (strncmp(buf, "external:", 9) == 0) {
 128                         sra->array.major_version = -1;
 129                         sra->array.minor_version = -2;
 130                         strcpy(sra->text_version, buf+9);
 131                 } else {
 132                         sscanf(buf, "%d.%d",
 133                                &sra->array.major_version,
 134                                &sra->array.minor_version);
 135                         strcpy(sra->text_version, buf);
 136                 }
 137         }
 138         if (options & GET_LEVEL) {
 139                 strcpy(base, "level");
 140                 if (load_sys(fname, buf))
 141                         goto abort;
 142                 sra->array.level = map_name(pers, buf);
 143         }
 144         if (options & GET_LAYOUT) {
 145                 strcpy(base, "layout");
 146                 if (load_sys(fname, buf))
 147                         goto abort;
 148                 sra->array.layout = strtoul(buf, NULL, 0);
 149         }
 150         if (options & GET_DISKS) {
 151                 strcpy(base, "raid_disks");
 152                 if (load_sys(fname, buf))
 153                         goto abort;
 154                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 155         }
 156         if (options & GET_COMPONENT) {
 157                 strcpy(base, "component_size");
 158                 if (load_sys(fname, buf))
 159                         goto abort;
 160                 sra->component_size = strtoull(buf, NULL, 0);
 161                 /* sysfs reports "K", but we want sectors */
 162                 sra->component_size *= 2;
 163         }
 164         if (options & GET_CHUNK) {
 165                 strcpy(base, "chunk_size");
 166                 if (load_sys(fname, buf))
 167                         goto abort;
 168                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 169         }
 170         if (options & GET_CACHE) {
 171                 strcpy(base, "stripe_cache_size");
 172                 if (load_sys(fname, buf))
 173                         goto abort;
 174                 sra->cache_size = strtoul(buf, NULL, 0);
 175         }
 176         if (options & GET_MISMATCH) {
 177                 strcpy(base, "mismatch_cnt");
 178                 if (load_sys(fname, buf))
 179                         goto abort;
 180                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 181         }
 182
 183         if (! (options & GET_DEVS))
 184                 return sra;
 185
 186         /* Get all the devices as well */
 187         *base = 0;
 188         dir = opendir(fname);
 189         if (!dir)
 190                 goto abort;
 191         sra->array.spare_disks = 0;
 192
 193         while ((de = readdir(dir)) != NULL) {
 194                 char *ep;
 195                 if (de->d_ino == 0 ||
 196                     strncmp(de->d_name, "dev-", 4) != 0)
 197                         continue;
 198                 strcpy(base, de->d_name);
 199                 dbase = base + strlen(base);
 200                 *dbase++ = '/';
 201
 202                 dev = malloc(sizeof(*dev));
 203                 if (!dev)
 204                         goto abort;
 205                 dev->next = sra->devs;
 206                 sra->devs = dev;
 207                 strcpy(dev->sys_name, de->d_name);
 208
 209                 /* Always get slot, major, minor */
 210                 strcpy(dbase, "slot");
 211                 if (load_sys(fname, buf))
 212                         goto abort;
 213                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 214                 if (*ep) dev->disk.raid_disk = -1;
 215
 216                 strcpy(dbase, "block/dev");
 217                 if (load_sys(fname, buf))
 218                         goto abort;
 219                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 220
 221                 if (options & GET_OFFSET) {
 222                         strcpy(dbase, "offset");
 223                         if (load_sys(fname, buf))
 224                                 goto abort;
 225                         dev->data_offset = strtoull(buf, NULL, 0);
 226                 }
 227                 if (options & GET_SIZE) {
 228                         strcpy(dbase, "size");
 229                         if (load_sys(fname, buf))
 230                                 goto abort;
 231                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 232                 }
 233                 if (options & GET_STATE) {
 234                         dev->disk.state = 0;
 235                         strcpy(dbase, "state");
 236                         if (load_sys(fname, buf))
 237                                 goto abort;
 238                         if (strstr(buf, "in_sync"))
 239                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 240                         if (strstr(buf, "faulty"))
 241                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 242                         if (dev->disk.state == 0)
 243                                 sra->array.spare_disks++;
 244                 }
 245                 if (options & GET_ERROR) {
 246                         strcpy(buf, "errors");
 247                         if (load_sys(fname, buf))
 248                                 goto abort;
 249                         dev->errors = strtoul(buf, NULL, 0);
 250                 }
 251         }
 252         closedir(dir);
 253         return sra;
 254
 255  abort:
 256         if (dir)
 257                 closedir(dir);
 258         sysfs_free(sra);
 259         return NULL;
 260 }
 261
 262 unsigned long long get_component_size(int fd)
 263 {
 264         /* Find out the component size of the array.
 265          * We cannot trust GET_ARRAY_INFO ioctl as it's
 266          * size field is only 32bits.
 267          * So look in /sys/block/mdXXX/md/component_size
 268          *
 269          * This returns in units of sectors.
 270          */
 271         struct stat stb;
 272         char fname[50];
 273         int n;
 274         if (fstat(fd, &stb)) return 0;
 275         if (major(stb.st_rdev) == 9)
 276                 sprintf(fname, "/sys/block/md%d/md/component_size",
 277                         (int)minor(stb.st_rdev));
 278         else
 279                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 280                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 281         fd = open(fname, O_RDONLY);
 282         if (fd < 0)
 283                 return 0;
 284         n = read(fd, fname, sizeof(fname));
 285         close(fd);
 286         if (n == sizeof(fname))
 287                 return 0;
 288         fname[n] = 0;
 289         return strtoull(fname, NULL, 10) * 2;
 290 }
 291
 292 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 293                   char *name, char *val)
 294 {
 295         char fname[50];
 296         int n;
 297         int fd;
 298
 299         sprintf(fname, "/sys/block/%s/md/%s/%s",
 300                 sra->sys_name, dev?dev->sys_name:"", name);
 301         fd = open(fname, O_WRONLY);
 302         if (fd < 0)
 303                 return -1;
 304         n = write(fd, val, strlen(val));
 305         close(fd);
 306         if (n != strlen(val))
 307                 return -1;
 308         return 0;
 309 }
 310
 311 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 312                   char *name, unsigned long long val)
 313 {
 314         char valstr[50];
 315         sprintf(valstr, "%llu", val);
 316         return sysfs_set_str(sra, dev, name, valstr);
 317 }
 318
 319 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 320                        char *name, unsigned long long *val)
 321 {
 322         char fname[50];
 323         char buf[50];
 324         int n;
 325         int fd;
 326         char *ep;
 327         sprintf(fname, "/sys/block/%s/md/%s/%s",
 328                 sra->sys_name, dev?dev->sys_name:"", name);
 329         fd = open(fname, O_RDONLY);
 330         if (fd < 0)
 331                 return -1;
 332         n = read(fd, buf, sizeof(buf));
 333         close(fd);
 334         if (n <= 0)
 335                 return -1;
 336         buf[n] = 0;
 337         *val = strtoull(buf, &ep, 0);
 338         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 339                 return -1;
 340         return 0;
 341 }
 342
 343 int sysfs_set_array(struct mdinfo *sra,
 344                     struct mdinfo *info)
 345 {
 346         int rv = 0;
 347         sra->array = info->array;
 348
 349         if (info->array.level < 0)
 350                 return 0; /* FIXME */
 351         rv |= sysfs_set_str(sra, NULL, "level",
 352                             map_num(pers, info->array.level));
 353         rv |= sysfs_set_num(sra, NULL, "raid_disks", info->array.raid_disks);
 354         rv |= sysfs_set_num(sra, NULL, "chunk_size", info->array.chunk_size);
 355         rv |= sysfs_set_num(sra, NULL, "layout", info->array.layout);
 356         rv |= sysfs_set_num(sra, NULL, "component_size", info->component_size/2);
 357         rv |= sysfs_set_num(sra, NULL, "resync_start", info->resync_start);
 358         sra->array = info->array;
 359         return rv;
 360 }
 361
 362 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd)
 363 {
 364         char dv[100];
 365         char nm[100];
 366         struct mdinfo *sd2;
 367         char *dname;
 368         int rv;
 369
 370         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 371         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 372         if (rv)
 373                 return rv;
 374
 375         memset(nm, 0, sizeof(nm));
 376         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 377         if (readlink(dv, nm, sizeof(nm)) < 0)
 378                 return -1;
 379         dname = strrchr(nm, '/');
 380         if (dname) dname++;
 381         strcpy(sd->sys_name, "dev-");
 382         strcpy(sd->sys_name+4, dname);
 383
 384         rv |= sysfs_set_num(sra, sd, "offset", sd->data_offset);
 385         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 386         if (sra->array.level != LEVEL_CONTAINER) {
 387                 rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 388 //              rv |= sysfs_set_str(sra, sd, "state", "in_sync");
 389         }
 390         if (! rv) {
 391                 sd2 = malloc(sizeof(*sd2));
 392                 *sd2 = *sd;
 393                 sd2->next = sra->devs;
 394                 sra->devs = sd2;
 395         }
 396         return rv;
 397 }
 398
 399 int sysfs_disk_to_sg(int fd)
 400 {
 401         /* from an open block device, try find and open its corresponding
 402          * scsi_generic interface
 403          */
 404         struct stat st;
 405         char path[256];
 406         char sg_path[256];
 407         char sg_major_minor[8];
 408         char *c;
 409         DIR *dir;
 410         struct dirent *de;
 411         int major, minor, rv;
 412
 413         if (fstat(fd, &st))
 414                 return -1;
 415
 416         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 417                  major(st.st_rdev), minor(st.st_rdev));
 418
 419         dir = opendir(path);
 420         if (!dir)
 421                 return -1;
 422
 423         de = readdir(dir);
 424         while (de) {
 425                 if (strncmp("scsi_generic:", de->d_name,
 426                             strlen("scsi_generic:")) == 0)
 427                         break;
 428                 de = readdir(dir);
 429         }
 430         closedir(dir);
 431
 432         if (!de)
 433                 return -1;
 434
 435         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 436         fd = open(sg_path, O_RDONLY);
 437         if (fd < 0)
 438                 return fd;
 439
 440         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 441         close(fd);
 442         if (rv < 0)
 443                 return -1;
 444         else
 445                 sg_major_minor[rv - 1] = '\0';
 446
 447         c = strchr(sg_major_minor, ':');
 448         *c = '\0';
 449         c++;
 450         major = strtol(sg_major_minor, NULL, 10);
 451         minor = strtol(c, NULL, 10);
 452         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 453                  (int) getpid(), major, minor);
 454         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 455                         fd = open(path, O_RDONLY);
 456                         unlink(path);
 457                         return fd;
 458         }
 459
 460         return -1;
 461 }
 462
 463 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 464 {
 465         /* from an open block device, try to retrieve it scsi_id */
 466         struct stat st;
 467         char path[256];
 468         char *c1, *c2;
 469         DIR *dir;
 470         struct dirent *de;
 471
 472         if (fstat(fd, &st))
 473                 return 1;
 474
 475         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 476                  major(st.st_rdev), minor(st.st_rdev));
 477
 478         dir = opendir(path);
 479         if (!dir)
 480                 return 1;
 481
 482         de = readdir(dir);
 483         while (de) {
 484                 if (strncmp("scsi_disk:", de->d_name,
 485                             strlen("scsi_disk:")) == 0)
 486                         break;
 487                 de = readdir(dir);
 488         }
 489         closedir(dir);
 490
 491         if (!de)
 492                 return 1;
 493
 494         c1 = strchr(de->d_name, ':');
 495         c1++;
 496         c2 = strchr(c1, ':');
 497         *c2 = '\0';
 498         *id = strtol(c1, NULL, 10) << 24; /* host */
 499         c1 = c2 + 1;
 500         c2 = strchr(c1, ':');
 501         *c2 = '\0';
 502         *id |= strtol(c1, NULL, 10) << 16; /* channel */
 503         c1 = c2 + 1;
 504         c2 = strchr(c1, ':');
 505         *c2 = '\0';
 506         *id |= strtol(c1, NULL, 10) << 8; /* lun */
 507         c1 = c2 + 1;
 508         *id |= strtol(c1, NULL, 10); /* id */
 509
 510         return 0;
 511 }
 512
 513
 514 int sysfs_unique_holder(int devnum, long rdev)
 515 {
 516         /* Check that devnum is a holder of rdev,
 517          * and is the only holder.
 518          * we should be locked against races by
 519          * an O_EXCL on devnum
 520          */
 521         DIR *dir;
 522         struct dirent *de;
 523         char dirname[100];
 524         char l;
 525         int found = 0;
 526         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 527                 major(rdev), minor(rdev));
 528         dir = opendir(dirname);
 529         errno = ENOENT;
 530         if (!dir)
 531                 return 0;
 532         l = strlen(dirname);
 533         while ((de = readdir(dir)) != NULL) {
 534                 char buf[10];
 535                 int n;
 536                 int mj, mn;
 537                 char c;
 538                 int fd;
 539
 540                 if (de->d_ino == 0)
 541                         continue;
 542                 if (de->d_name[0] == '.')
 543                         continue;
 544                 strcpy(dirname+l, "/");
 545                 strcat(dirname+l, de->d_name);
 546                 strcat(dirname+l, "/dev");
 547                 fd = open(dirname, O_RDONLY);
 548                 if (fd < 0) {
 549                         errno = ENOENT;
 550                         break;
 551                 }
 552                 n = read(fd, buf, sizeof(buf)-1);
 553                 close(fd);
 554                 buf[n] = 0;
 555                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 556                     c != '\n') {
 557                         errno = ENOENT;
 558                         break;
 559                 }
 560                 if (mj != MD_MAJOR)
 561                         mn = -1-(mn>>6);
 562
 563                 if (devnum != mn) {
 564                         errno = EEXIST;
 565                         break;
 566                 }
 567                 found = 1;
 568         }
 569         closedir(dir);
 570         if (de)
 571                 return 0;
 572         else
 573                 return found;
 574 }