src/udev/udev-builtin-path_id.c

   1 /*
   2  * compose persistent device path
   3  *
   4  * Copyright (C) 2009-2011 Kay Sievers <kay@vrfy.org>
   5  *
   6  * Logic based on Hannes Reinecke's shell script.
   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, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <stdarg.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <fcntl.h>
  29 #include <errno.h>
  30 #include <dirent.h>
  31 #include <getopt.h>
  32
  33 #include "udev.h"
  34
  35 _printf_(2,3)
  36 static int path_prepend(char **path, const char *fmt, ...)
  37 {
  38         va_list va;
  39         char *pre;
  40         int err = 0;
  41
  42         va_start(va, fmt);
  43         err = vasprintf(&pre, fmt, va);
  44         va_end(va);
  45         if (err < 0)
  46                 goto out;
  47
  48         if (*path != NULL) {
  49                 char *new;
  50
  51                 err = asprintf(&new, "%s-%s", pre, *path);
  52                 free(pre);
  53                 if (err < 0)
  54                         goto out;
  55                 free(*path);
  56                 *path = new;
  57         } else {
  58                 *path = pre;
  59         }
  60 out:
  61         return err;
  62 }
  63
  64 /*
  65 ** Linux only supports 32 bit luns.
  66 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
  67 */
  68 static int format_lun_number(struct udev_device *dev, char **path)
  69 {
  70         unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
  71
  72         /* address method 0, peripheral device addressing with bus id of zero */
  73         if (lun < 256)
  74                 return path_prepend(path, "lun-%lu", lun);
  75         /* handle all other lun addressing methods by using a variant of the original lun format */
  76         return path_prepend(path, "lun-0x%04lx%04lx00000000", lun & 0xffff, (lun >> 16) & 0xffff);
  77 }
  78
  79 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys)
  80 {
  81         struct udev_device *parent = dev;
  82
  83         while (parent != NULL) {
  84                 const char *subsystem;
  85
  86                 subsystem = udev_device_get_subsystem(parent);
  87                 if (subsystem == NULL || !streq(subsystem, subsys))
  88                         break;
  89                 dev = parent;
  90                 parent = udev_device_get_parent(parent);
  91         }
  92         return dev;
  93 }
  94
  95 static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent, char **path)
  96 {
  97         struct udev *udev  = udev_device_get_udev(parent);
  98         struct udev_device *targetdev;
  99         struct udev_device *fcdev = NULL;
 100         const char *port;
 101         char *lun = NULL;
 102
 103         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 104         if (targetdev == NULL)
 105                 return NULL;
 106
 107         fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
 108         if (fcdev == NULL)
 109                 return NULL;
 110         port = udev_device_get_sysattr_value(fcdev, "port_name");
 111         if (port == NULL) {
 112                 parent = NULL;
 113                 goto out;
 114         }
 115
 116         format_lun_number(parent, &lun);
 117         path_prepend(path, "fc-%s-%s", port, lun);
 118         if (lun)
 119                 free(lun);
 120 out:
 121         udev_device_unref(fcdev);
 122         return parent;
 123 }
 124
 125 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
 126 {
 127         struct udev *udev  = udev_device_get_udev(parent);
 128         struct udev_device *targetdev;
 129         struct udev_device *target_parent;
 130         struct udev_device *sasdev;
 131         const char *sas_address;
 132         char *lun = NULL;
 133
 134         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 135         if (targetdev == NULL)
 136                 return NULL;
 137
 138         target_parent = udev_device_get_parent(targetdev);
 139         if (target_parent == NULL)
 140                 return NULL;
 141
 142         sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
 143                                 udev_device_get_sysname(target_parent));
 144         if (sasdev == NULL)
 145                 return NULL;
 146
 147         sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
 148         if (sas_address == NULL) {
 149                 parent = NULL;
 150                 goto out;
 151         }
 152
 153         format_lun_number(parent, &lun);
 154         path_prepend(path, "sas-%s-%s", sas_address, lun);
 155         if (lun)
 156                 free(lun);
 157 out:
 158         udev_device_unref(sasdev);
 159         return parent;
 160 }
 161
 162 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path)
 163 {
 164         struct udev *udev  = udev_device_get_udev(parent);
 165         struct udev_device *transportdev;
 166         struct udev_device *sessiondev = NULL;
 167         const char *target;
 168         char *connname;
 169         struct udev_device *conndev = NULL;
 170         const char *addr;
 171         const char *port;
 172         char *lun = NULL;
 173
 174         /* find iscsi session */
 175         transportdev = parent;
 176         for (;;) {
 177                 transportdev = udev_device_get_parent(transportdev);
 178                 if (transportdev == NULL)
 179                         return NULL;
 180                 if (startswith(udev_device_get_sysname(transportdev), "session"))
 181                         break;
 182         }
 183
 184         /* find iscsi session device */
 185         sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
 186         if (sessiondev == NULL)
 187                 return NULL;
 188         target = udev_device_get_sysattr_value(sessiondev, "targetname");
 189         if (target == NULL) {
 190                 parent = NULL;
 191                 goto out;
 192         }
 193
 194         if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
 195                 parent = NULL;
 196                 goto out;
 197         }
 198         conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
 199         free(connname);
 200         if (conndev == NULL) {
 201                 parent = NULL;
 202                 goto out;
 203         }
 204         addr = udev_device_get_sysattr_value(conndev, "persistent_address");
 205         port = udev_device_get_sysattr_value(conndev, "persistent_port");
 206         if (addr == NULL || port == NULL) {
 207                 parent = NULL;
 208                 goto out;
 209         }
 210
 211         format_lun_number(parent, &lun);
 212         path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 213         if (lun)
 214                 free(lun);
 215 out:
 216         udev_device_unref(sessiondev);
 217         udev_device_unref(conndev);
 218         return parent;
 219 }
 220
 221 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path)
 222 {
 223         struct udev_device *hostdev;
 224         int host, bus, target, lun;
 225         const char *name;
 226         char *base;
 227         char *pos;
 228         DIR *dir;
 229         struct dirent *dent;
 230         int basenum;
 231
 232         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 233         if (hostdev == NULL)
 234                 return NULL;
 235
 236         name = udev_device_get_sysname(parent);
 237         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 238                 return NULL;
 239
 240         /*
 241          * Rebase host offset to get the local relative number
 242          *
 243          * Note: This is by definition racy, unreliable and too simple.
 244          * Please do not copy this model anywhere. It's just a left-over
 245          * from the time we had no idea how things should look like in
 246          * the end.
 247          *
 248          * Making assumptions about a global in-kernel counter and use
 249          * that to calculate a local offset is a very broken concept. It
 250          * can only work as long as things are in strict order.
 251          *
 252          * The kernel needs to export the instance/port number of a
 253          * controller directly, without the need for rebase magic like
 254          * this. Manual driver unbind/bind, parallel hotplug/unplug will
 255          * get into the way of this "I hope it works" logic.
 256          */
 257         basenum = -1;
 258         base = strdup(udev_device_get_syspath(hostdev));
 259         if (base == NULL)
 260                 return NULL;
 261         pos = strrchr(base, '/');
 262         if (pos == NULL) {
 263                 parent = NULL;
 264                 goto out;
 265         }
 266         pos[0] = '\0';
 267         dir = opendir(base);
 268         if (dir == NULL) {
 269                 parent = NULL;
 270                 goto out;
 271         }
 272         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 273                 char *rest;
 274                 int i;
 275
 276                 if (dent->d_name[0] == '.')
 277                         continue;
 278                 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
 279                         continue;
 280                 if (!startswith(dent->d_name, "host"))
 281                         continue;
 282                 i = strtoul(&dent->d_name[4], &rest, 10);
 283                 if (rest[0] != '\0')
 284                         continue;
 285                 /*
 286                  * find the smallest number; the host really needs to export its
 287                  * own instance number per parent device; relying on the global host
 288                  * enumeration and plainly rebasing the numbers sounds unreliable
 289                  */
 290                 if (basenum == -1 || i < basenum)
 291                         basenum = i;
 292         }
 293         closedir(dir);
 294         if (basenum == -1) {
 295                 parent = NULL;
 296                 goto out;
 297         }
 298         host -= basenum;
 299
 300         path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
 301 out:
 302         free(base);
 303         return hostdev;
 304 }
 305
 306 static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char **path) {
 307         struct udev_device *hostdev;
 308         struct udev_device *vmbusdev;
 309         const char *guid_str;
 310         char *lun = NULL;
 311         char guid[38];
 312         size_t i, k;
 313
 314         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 315         if (!hostdev)
 316                 return NULL;
 317
 318         vmbusdev = udev_device_get_parent(hostdev);
 319         if (!vmbusdev)
 320                 return NULL;
 321
 322         guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
 323         if (!guid_str)
 324                 return NULL;
 325
 326         if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
 327                 return NULL;
 328
 329         for (i = 1, k = 0; i < 36; i++) {
 330                 if (guid_str[i] == '-')
 331                         continue;
 332                 guid[k++] = guid_str[i];
 333         }
 334         guid[k] = '\0';
 335
 336         format_lun_number(parent, &lun);
 337         path_prepend(path, "vmbus-%s-%s", guid, lun);
 338         free(lun);
 339         return parent;
 340 }
 341
 342 static struct udev_device *handle_scsi(struct udev_device *parent, char **path)
 343 {
 344         const char *devtype;
 345         const char *name;
 346         const char *id;
 347
 348         devtype = udev_device_get_devtype(parent);
 349         if (devtype == NULL || !streq(devtype, "scsi_device"))
 350                 return parent;
 351
 352         /* firewire */
 353         id = udev_device_get_sysattr_value(parent, "ieee1394_id");
 354         if (id != NULL) {
 355                 parent = skip_subsystem(parent, "scsi");
 356                 path_prepend(path, "ieee1394-0x%s", id);
 357                 goto out;
 358         }
 359
 360         /* scsi sysfs does not have a "subsystem" for the transport */
 361         name = udev_device_get_syspath(parent);
 362
 363         if (strstr(name, "/rport-") != NULL) {
 364                 parent = handle_scsi_fibre_channel(parent, path);
 365                 goto out;
 366         }
 367
 368         if (strstr(name, "/end_device-") != NULL) {
 369                 parent = handle_scsi_sas(parent, path);
 370                 goto out;
 371         }
 372
 373         if (strstr(name, "/session") != NULL) {
 374                 parent = handle_scsi_iscsi(parent, path);
 375                 goto out;
 376         }
 377
 378         /*
 379          * We do not support the ATA transport class, it uses global counters
 380          * to name the ata devices which numbers spread across multiple
 381          * controllers.
 382          *
 383          * The real link numbers are not exported. Also, possible chains of ports
 384          * behind port multipliers cannot be composed that way.
 385          *
 386          * Until all that is solved at the kernel level, there are no by-path/
 387          * links for ATA devices.
 388          */
 389         if (strstr(name, "/ata") != NULL) {
 390                 parent = NULL;
 391                 goto out;
 392         }
 393
 394         if (strstr(name, "/vmbus_") != NULL) {
 395                 parent = handle_scsi_hyperv(parent, path);
 396                 goto out;
 397         }
 398
 399         parent = handle_scsi_default(parent, path);
 400 out:
 401         return parent;
 402 }
 403
 404 static struct udev_device *handle_cciss(struct udev_device *parent, char **path)
 405 {
 406         const char *str;
 407         unsigned int controller, disk;
 408
 409         str = udev_device_get_sysname(parent);
 410         if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
 411                 return NULL;
 412
 413         path_prepend(path, "cciss-disk%u", disk);
 414         parent = skip_subsystem(parent, "cciss");
 415         return parent;
 416 }
 417
 418 static void handle_scsi_tape(struct udev_device *dev, char **path)
 419 {
 420         const char *name;
 421
 422         /* must be the last device in the syspath */
 423         if (*path != NULL)
 424                 return;
 425
 426         name = udev_device_get_sysname(dev);
 427         if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
 428                 path_prepend(path, "nst%c", name[3]);
 429         else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
 430                 path_prepend(path, "st%c", name[2]);
 431 }
 432
 433 static struct udev_device *handle_usb(struct udev_device *parent, char **path)
 434 {
 435         const char *devtype;
 436         const char *str;
 437         const char *port;
 438
 439         devtype = udev_device_get_devtype(parent);
 440         if (devtype == NULL)
 441                 return parent;
 442         if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
 443                 return parent;
 444
 445         str = udev_device_get_sysname(parent);
 446         port = strchr(str, '-');
 447         if (port == NULL)
 448                 return parent;
 449         port++;
 450
 451         parent = skip_subsystem(parent, "usb");
 452         path_prepend(path, "usb-0:%s", port);
 453         return parent;
 454 }
 455
 456 static struct udev_device *handle_bcma(struct udev_device *parent, char **path)
 457 {
 458         const char *sysname;
 459         unsigned int core;
 460
 461         sysname = udev_device_get_sysname(parent);
 462         if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
 463                 return NULL;
 464
 465         path_prepend(path, "bcma-%u", core);
 466         return parent;
 467 }
 468
 469 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path)
 470 {
 471         struct udev_device *scsi_dev;
 472
 473         scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
 474         if (scsi_dev != NULL) {
 475                 const char *wwpn;
 476                 const char *lun;
 477                 const char *hba_id;
 478
 479                 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
 480                 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
 481                 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
 482                 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
 483                         path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
 484                         goto out;
 485                 }
 486         }
 487
 488         path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
 489 out:
 490         parent = skip_subsystem(parent, "ccw");
 491         return parent;
 492 }
 493
 494 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test)
 495 {
 496         struct udev_device *parent;
 497         char *path = NULL;
 498         bool some_transport = false;
 499
 500         /* S390 ccw bus */
 501         parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
 502         if (parent != NULL) {
 503                 handle_ccw(parent, dev, &path);
 504                 goto out;
 505         }
 506
 507         /* walk up the chain of devices and compose path */
 508         parent = dev;
 509         while (parent != NULL) {
 510                 const char *subsys;
 511
 512                 subsys = udev_device_get_subsystem(parent);
 513                 if (subsys == NULL) {
 514                         ;
 515                 } else if (streq(subsys, "scsi_tape")) {
 516                         handle_scsi_tape(parent, &path);
 517                 } else if (streq(subsys, "scsi")) {
 518                         parent = handle_scsi(parent, &path);
 519                         some_transport = true;
 520                 } else if (streq(subsys, "cciss")) {
 521                         parent = handle_cciss(parent, &path);
 522                         some_transport = true;
 523                 } else if (streq(subsys, "usb")) {
 524                         parent = handle_usb(parent, &path);
 525                         some_transport = true;
 526                 } else if (streq(subsys, "bcma")) {
 527                         parent = handle_bcma(parent, &path);
 528                         some_transport = true;
 529                 } else if (streq(subsys, "serio")) {
 530                         path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
 531                         parent = skip_subsystem(parent, "serio");
 532                 } else if (streq(subsys, "pci")) {
 533                         path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
 534                         parent = skip_subsystem(parent, "pci");
 535                 } else if (streq(subsys, "platform")) {
 536                         path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
 537                         parent = skip_subsystem(parent, "platform");
 538                         some_transport = true;
 539                 } else if (streq(subsys, "acpi")) {
 540                         path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
 541                         parent = skip_subsystem(parent, "acpi");
 542                 } else if (streq(subsys, "xen")) {
 543                         path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
 544                         parent = skip_subsystem(parent, "xen");
 545                 } else if (streq(subsys, "scm")) {
 546                         path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
 547                         parent = skip_subsystem(parent, "scm");
 548                         some_transport = true;
 549                 }
 550
 551                 parent = udev_device_get_parent(parent);
 552         }
 553
 554         /*
 555          * Do not return a single-parent-device-only for block
 556          * devices, they might have entire buses behind it which
 557          * do not get unique IDs only by using the parent device.
 558          */
 559         if (!some_transport && streq(udev_device_get_subsystem(dev), "block")) {
 560                 free(path);
 561                 path = NULL;
 562         }
 563
 564 out:
 565         if (path != NULL) {
 566                 char tag[UTIL_NAME_SIZE];
 567                 size_t i;
 568                 const char *p;
 569
 570                 /* compose valid udev tag name */
 571                 for (p = path, i = 0; *p; p++) {
 572                         if ((*p >= '0' && *p <= '9') ||
 573                             (*p >= 'A' && *p <= 'Z') ||
 574                             (*p >= 'a' && *p <= 'z') ||
 575                             *p == '-') {
 576                                 tag[i++] = *p;
 577                                 continue;
 578                         }
 579
 580                         /* skip all leading '_' */
 581                         if (i == 0)
 582                                 continue;
 583
 584                         /* avoid second '_' */
 585                         if (tag[i-1] == '_')
 586                                 continue;
 587
 588                         tag[i++] = '_';
 589                 }
 590                 /* strip trailing '_' */
 591                 while (i > 0 && tag[i-1] == '_')
 592                         i--;
 593                 tag[i] = '\0';
 594
 595                 udev_builtin_add_property(dev, test, "ID_PATH", path);
 596                 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 597                 free(path);
 598                 return EXIT_SUCCESS;
 599         }
 600         return EXIT_FAILURE;
 601 }
 602
 603 const struct udev_builtin udev_builtin_path_id = {
 604         .name = "path_id",
 605         .cmd = builtin_path_id,
 606         .help = "compose persistent device path",
 607         .run_once = true,
 608 };