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 (n && 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_DEGRADED) {
 157                 strcpy(base, "degraded");
 158                 if (load_sys(fname, buf))
 159                         goto abort;
 160                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 161         }
 162         if (options & GET_COMPONENT) {
 163                 strcpy(base, "component_size");
 164                 if (load_sys(fname, buf))
 165                         goto abort;
 166                 sra->component_size = strtoull(buf, NULL, 0);
 167                 /* sysfs reports "K", but we want sectors */
 168                 sra->component_size *= 2;
 169         }
 170         if (options & GET_CHUNK) {
 171                 strcpy(base, "chunk_size");
 172                 if (load_sys(fname, buf))
 173                         goto abort;
 174                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 175         }
 176         if (options & GET_CACHE) {
 177                 strcpy(base, "stripe_cache_size");
 178                 if (load_sys(fname, buf))
 179                         goto abort;
 180                 sra->cache_size = strtoul(buf, NULL, 0);
 181         }
 182         if (options & GET_MISMATCH) {
 183                 strcpy(base, "mismatch_cnt");
 184                 if (load_sys(fname, buf))
 185                         goto abort;
 186                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 187         }
 188
 189         if (! (options & GET_DEVS))
 190                 return sra;
 191
 192         /* Get all the devices as well */
 193         *base = 0;
 194         dir = opendir(fname);
 195         if (!dir)
 196                 goto abort;
 197         sra->array.spare_disks = 0;
 198
 199         while ((de = readdir(dir)) != NULL) {
 200                 char *ep;
 201                 if (de->d_ino == 0 ||
 202                     strncmp(de->d_name, "dev-", 4) != 0)
 203                         continue;
 204                 strcpy(base, de->d_name);
 205                 dbase = base + strlen(base);
 206                 *dbase++ = '/';
 207
 208                 dev = malloc(sizeof(*dev));
 209                 if (!dev)
 210                         goto abort;
 211                 dev->next = sra->devs;
 212                 sra->devs = dev;
 213                 strcpy(dev->sys_name, de->d_name);
 214
 215                 /* Always get slot, major, minor */
 216                 strcpy(dbase, "slot");
 217                 if (load_sys(fname, buf))
 218                         goto abort;
 219                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 220                 if (*ep) dev->disk.raid_disk = -1;
 221
 222                 strcpy(dbase, "block/dev");
 223                 if (load_sys(fname, buf))
 224                         goto abort;
 225                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 226
 227                 if (options & GET_OFFSET) {
 228                         strcpy(dbase, "offset");
 229                         if (load_sys(fname, buf))
 230                                 goto abort;
 231                         dev->data_offset = strtoull(buf, NULL, 0);
 232                 }
 233                 if (options & GET_SIZE) {
 234                         strcpy(dbase, "size");
 235                         if (load_sys(fname, buf))
 236                                 goto abort;
 237                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 238                 }
 239                 if (options & GET_STATE) {
 240                         dev->disk.state = 0;
 241                         strcpy(dbase, "state");
 242                         if (load_sys(fname, buf))
 243                                 goto abort;
 244                         if (strstr(buf, "in_sync"))
 245                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 246                         if (strstr(buf, "faulty"))
 247                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 248                         if (dev->disk.state == 0)
 249                                 sra->array.spare_disks++;
 250                 }
 251                 if (options & GET_ERROR) {
 252                         strcpy(buf, "errors");
 253                         if (load_sys(fname, buf))
 254                                 goto abort;
 255                         dev->errors = strtoul(buf, NULL, 0);
 256                 }
 257         }
 258         closedir(dir);
 259         return sra;
 260
 261  abort:
 262         if (dir)
 263                 closedir(dir);
 264         sysfs_free(sra);
 265         return NULL;
 266 }
 267
 268 unsigned long long get_component_size(int fd)
 269 {
 270         /* Find out the component size of the array.
 271          * We cannot trust GET_ARRAY_INFO ioctl as it's
 272          * size field is only 32bits.
 273          * So look in /sys/block/mdXXX/md/component_size
 274          *
 275          * This returns in units of sectors.
 276          */
 277         struct stat stb;
 278         char fname[50];
 279         int n;
 280         if (fstat(fd, &stb)) return 0;
 281         if (major(stb.st_rdev) == 9)
 282                 sprintf(fname, "/sys/block/md%d/md/component_size",
 283                         (int)minor(stb.st_rdev));
 284         else
 285                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 286                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 287         fd = open(fname, O_RDONLY);
 288         if (fd < 0)
 289                 return 0;
 290         n = read(fd, fname, sizeof(fname));
 291         close(fd);
 292         if (n == sizeof(fname))
 293                 return 0;
 294         fname[n] = 0;
 295         return strtoull(fname, NULL, 10) * 2;
 296 }
 297
 298 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 299                   char *name, char *val)
 300 {
 301         char fname[50];
 302         int n;
 303         int fd;
 304
 305         sprintf(fname, "/sys/block/%s/md/%s/%s",
 306                 sra->sys_name, dev?dev->sys_name:"", name);
 307         fd = open(fname, O_WRONLY);
 308         if (fd < 0)
 309                 return -1;
 310         n = write(fd, val, strlen(val));
 311         close(fd);
 312         if (n != strlen(val))
 313                 return -1;
 314         return 0;
 315 }
 316
 317 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 318                   char *name, unsigned long long val)
 319 {
 320         char valstr[50];
 321         sprintf(valstr, "%llu", val);
 322         return sysfs_set_str(sra, dev, name, valstr);
 323 }
 324
 325 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 326                        char *name, unsigned long long *val)
 327 {
 328         char fname[50];
 329         char buf[50];
 330         int n;
 331         int fd;
 332         char *ep;
 333         sprintf(fname, "/sys/block/%s/md/%s/%s",
 334                 sra->sys_name, dev?dev->sys_name:"", name);
 335         fd = open(fname, O_RDONLY);
 336         if (fd < 0)
 337                 return -1;
 338         n = read(fd, buf, sizeof(buf));
 339         close(fd);
 340         if (n <= 0)
 341                 return -1;
 342         buf[n] = 0;
 343         *val = strtoull(buf, &ep, 0);
 344         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 345                 return -1;
 346         return 0;
 347 }
 348
 349 int sysfs_set_array(struct mdinfo *sra,
 350                     struct mdinfo *info)
 351 {
 352         int rv = 0;
 353         sra->array = info->array;
 354
 355         if (info->array.level < 0)
 356                 return 0; /* FIXME */
 357         rv |= sysfs_set_str(sra, NULL, "level",
 358                             map_num(pers, info->array.level));
 359         rv |= sysfs_set_num(sra, NULL, "raid_disks", info->array.raid_disks);
 360         rv |= sysfs_set_num(sra, NULL, "chunk_size", info->array.chunk_size);
 361         rv |= sysfs_set_num(sra, NULL, "layout", info->array.layout);
 362         rv |= sysfs_set_num(sra, NULL, "component_size", info->component_size/2);
 363         rv |= sysfs_set_num(sra, NULL, "resync_start", info->resync_start);
 364         sra->array = info->array;
 365         return rv;
 366 }
 367
 368 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd)
 369 {
 370         char dv[100];
 371         char nm[100];
 372         struct mdinfo *sd2;
 373         char *dname;
 374         int rv;
 375
 376         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 377         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 378         if (rv)
 379                 return rv;
 380
 381         memset(nm, 0, sizeof(nm));
 382         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 383         rv = readlink(dv, nm, sizeof(nm));
 384         if (rv <= 0)
 385                 return -1;
 386         nm[rv] = '\0';
 387         dname = strrchr(nm, '/');
 388         if (dname) dname++;
 389         strcpy(sd->sys_name, "dev-");
 390         strcpy(sd->sys_name+4, dname);
 391
 392         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 393         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 394         if (sra->array.level != LEVEL_CONTAINER) {
 395                 rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 396 //              rv |= sysfs_set_str(sra, sd, "state", "in_sync");
 397         }
 398         if (! rv) {
 399                 sd2 = malloc(sizeof(*sd2));
 400                 *sd2 = *sd;
 401                 sd2->next = sra->devs;
 402                 sra->devs = sd2;
 403         }
 404         return rv;
 405 }
 406
 407 #if 0
 408 int sysfs_disk_to_sg(int fd)
 409 {
 410         /* from an open block device, try find and open its corresponding
 411          * scsi_generic interface
 412          */
 413         struct stat st;
 414         char path[256];
 415         char sg_path[256];
 416         char sg_major_minor[8];
 417         char *c;
 418         DIR *dir;
 419         struct dirent *de;
 420         int major, minor, rv;
 421
 422         if (fstat(fd, &st))
 423                 return -1;
 424
 425         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 426                  major(st.st_rdev), minor(st.st_rdev));
 427
 428         dir = opendir(path);
 429         if (!dir)
 430                 return -1;
 431
 432         de = readdir(dir);
 433         while (de) {
 434                 if (strncmp("scsi_generic:", de->d_name,
 435                             strlen("scsi_generic:")) == 0)
 436                         break;
 437                 de = readdir(dir);
 438         }
 439         closedir(dir);
 440
 441         if (!de)
 442                 return -1;
 443
 444         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 445         fd = open(sg_path, O_RDONLY);
 446         if (fd < 0)
 447                 return fd;
 448
 449         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 450         close(fd);
 451         if (rv < 0)
 452                 return -1;
 453         else
 454                 sg_major_minor[rv - 1] = '\0';
 455
 456         c = strchr(sg_major_minor, ':');
 457         *c = '\0';
 458         c++;
 459         major = strtol(sg_major_minor, NULL, 10);
 460         minor = strtol(c, NULL, 10);
 461         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 462                  (int) getpid(), major, minor);
 463         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 464                         fd = open(path, O_RDONLY);
 465                         unlink(path);
 466                         return fd;
 467         }
 468
 469         return -1;
 470 }
 471 #endif
 472
 473 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 474 {
 475         /* from an open block device, try to retrieve it scsi_id */
 476         struct stat st;
 477         char path[256];
 478         char *c1, *c2;
 479         DIR *dir;
 480         struct dirent *de;
 481
 482         if (fstat(fd, &st))
 483                 return 1;
 484
 485         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 486                  major(st.st_rdev), minor(st.st_rdev));
 487
 488         dir = opendir(path);
 489         if (!dir)
 490                 return 1;
 491
 492         de = readdir(dir);
 493         while (de) {
 494                 if (strncmp("scsi_disk:", de->d_name,
 495                             strlen("scsi_disk:")) == 0)
 496                         break;
 497                 de = readdir(dir);
 498         }
 499         closedir(dir);
 500
 501         if (!de)
 502                 return 1;
 503
 504         c1 = strchr(de->d_name, ':');
 505         c1++;
 506         c2 = strchr(c1, ':');
 507         *c2 = '\0';
 508         *id = strtol(c1, NULL, 10) << 24; /* host */
 509         c1 = c2 + 1;
 510         c2 = strchr(c1, ':');
 511         *c2 = '\0';
 512         *id |= strtol(c1, NULL, 10) << 16; /* channel */
 513         c1 = c2 + 1;
 514         c2 = strchr(c1, ':');
 515         *c2 = '\0';
 516         *id |= strtol(c1, NULL, 10) << 8; /* lun */
 517         c1 = c2 + 1;
 518         *id |= strtol(c1, NULL, 10); /* id */
 519
 520         return 0;
 521 }
 522
 523
 524 int sysfs_unique_holder(int devnum, long rdev)
 525 {
 526         /* Check that devnum is a holder of rdev,
 527          * and is the only holder.
 528          * we should be locked against races by
 529          * an O_EXCL on devnum
 530          */
 531         DIR *dir;
 532         struct dirent *de;
 533         char dirname[100];
 534         char l;
 535         int found = 0;
 536         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 537                 major(rdev), minor(rdev));
 538         dir = opendir(dirname);
 539         errno = ENOENT;
 540         if (!dir)
 541                 return 0;
 542         l = strlen(dirname);
 543         while ((de = readdir(dir)) != NULL) {
 544                 char buf[10];
 545                 int n;
 546                 int mj, mn;
 547                 char c;
 548                 int fd;
 549
 550                 if (de->d_ino == 0)
 551                         continue;
 552                 if (de->d_name[0] == '.')
 553                         continue;
 554                 strcpy(dirname+l, "/");
 555                 strcat(dirname+l, de->d_name);
 556                 strcat(dirname+l, "/dev");
 557                 fd = open(dirname, O_RDONLY);
 558                 if (fd < 0) {
 559                         errno = ENOENT;
 560                         break;
 561                 }
 562                 n = read(fd, buf, sizeof(buf)-1);
 563                 close(fd);
 564                 buf[n] = 0;
 565                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 566                     c != '\n') {
 567                         errno = ENOENT;
 568                         break;
 569                 }
 570                 if (mj != MD_MAJOR)
 571                         mn = -1-(mn>>6);
 572
 573                 if (devnum != mn) {
 574                         errno = EEXIST;
 575                         break;
 576                 }
 577                 found = 1;
 578         }
 579         closedir(dir);
 580         if (de)
 581                 return 0;
 582         else
 583                 return found;
 584 }