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         va_list va;
  38         char *pre;
  39         int err = 0;
  40
  41         va_start(va, fmt);
  42         err = vasprintf(&pre, fmt, va);
  43         va_end(va);
  44         if (err < 0)
  45                 goto out;
  46
  47         if (*path != NULL) {
  48                 char *new;
  49
  50                 err = asprintf(&new, "%s-%s", pre, *path);
  51                 free(pre);
  52                 if (err < 0)
  53                         goto out;
  54                 free(*path);
  55                 *path = new;
  56         } else {
  57                 *path = pre;
  58         }
  59 out:
  60         return err;
  61 }
  62
  63 /*
  64 ** Linux only supports 32 bit luns.
  65 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
  66 */
  67 static int format_lun_number(struct udev_device *dev, char **path) {
  68         unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
  69
  70         /* address method 0, peripheral device addressing with bus id of zero */
  71         if (lun < 256)
  72                 return path_prepend(path, "lun-%lu", lun);
  73         /* handle all other lun addressing methods by using a variant of the original lun format */
  74         return path_prepend(path, "lun-0x%04lx%04lx00000000", lun & 0xffff, (lun >> 16) & 0xffff);
  75 }
  76
  77 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys) {
  78         struct udev_device *parent = dev;
  79
  80         while (parent != NULL) {
  81                 const char *subsystem;
  82
  83                 subsystem = udev_device_get_subsystem(parent);
  84                 if (subsystem == NULL || !streq(subsystem, subsys))
  85                         break;
  86                 dev = parent;
  87                 parent = udev_device_get_parent(parent);
  88         }
  89         return dev;
  90 }
  91
  92 static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent, char **path) {
  93         struct udev *udev  = udev_device_get_udev(parent);
  94         struct udev_device *targetdev;
  95         struct udev_device *fcdev = NULL;
  96         const char *port;
  97         char *lun = NULL;
  98
  99         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 100         if (targetdev == NULL)
 101                 return NULL;
 102
 103         fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
 104         if (fcdev == NULL)
 105                 return NULL;
 106         port = udev_device_get_sysattr_value(fcdev, "port_name");
 107         if (port == NULL) {
 108                 parent = NULL;
 109                 goto out;
 110         }
 111
 112         format_lun_number(parent, &lun);
 113         path_prepend(path, "fc-%s-%s", port, lun);
 114         if (lun)
 115                 free(lun);
 116 out:
 117         udev_device_unref(fcdev);
 118         return parent;
 119 }
 120
 121 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path) {
 122         struct udev *udev  = udev_device_get_udev(parent);
 123         struct udev_device *targetdev;
 124         struct udev_device *target_parent;
 125         struct udev_device *sasdev;
 126         const char *sas_address;
 127         char *lun = NULL;
 128
 129         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 130         if (targetdev == NULL)
 131                 return NULL;
 132
 133         target_parent = udev_device_get_parent(targetdev);
 134         if (target_parent == NULL)
 135                 return NULL;
 136
 137         sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
 138                                 udev_device_get_sysname(target_parent));
 139         if (sasdev == NULL)
 140                 return NULL;
 141
 142         sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
 143         if (sas_address == NULL) {
 144                 parent = NULL;
 145                 goto out;
 146         }
 147
 148         format_lun_number(parent, &lun);
 149         path_prepend(path, "sas-%s-%s", sas_address, lun);
 150         if (lun)
 151                 free(lun);
 152 out:
 153         udev_device_unref(sasdev);
 154         return parent;
 155 }
 156
 157 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path) {
 158         struct udev *udev  = udev_device_get_udev(parent);
 159         struct udev_device *transportdev;
 160         struct udev_device *sessiondev = NULL;
 161         const char *target;
 162         char *connname;
 163         struct udev_device *conndev = NULL;
 164         const char *addr;
 165         const char *port;
 166         char *lun = NULL;
 167
 168         /* find iscsi session */
 169         transportdev = parent;
 170         for (;;) {
 171                 transportdev = udev_device_get_parent(transportdev);
 172                 if (transportdev == NULL)
 173                         return NULL;
 174                 if (startswith(udev_device_get_sysname(transportdev), "session"))
 175                         break;
 176         }
 177
 178         /* find iscsi session device */
 179         sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
 180         if (sessiondev == NULL)
 181                 return NULL;
 182         target = udev_device_get_sysattr_value(sessiondev, "targetname");
 183         if (target == NULL) {
 184                 parent = NULL;
 185                 goto out;
 186         }
 187
 188         if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
 189                 parent = NULL;
 190                 goto out;
 191         }
 192         conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
 193         free(connname);
 194         if (conndev == NULL) {
 195                 parent = NULL;
 196                 goto out;
 197         }
 198         addr = udev_device_get_sysattr_value(conndev, "persistent_address");
 199         port = udev_device_get_sysattr_value(conndev, "persistent_port");
 200         if (addr == NULL || port == NULL) {
 201                 parent = NULL;
 202                 goto out;
 203         }
 204
 205         format_lun_number(parent, &lun);
 206         path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 207         if (lun)
 208                 free(lun);
 209 out:
 210         udev_device_unref(sessiondev);
 211         udev_device_unref(conndev);
 212         return parent;
 213 }
 214
 215 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path) {
 216         struct udev_device *hostdev;
 217         int host, bus, target, lun;
 218         const char *name;
 219         char *base;
 220         char *pos;
 221         DIR *dir;
 222         struct dirent *dent;
 223         int basenum;
 224
 225         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 226         if (hostdev == NULL)
 227                 return NULL;
 228
 229         name = udev_device_get_sysname(parent);
 230         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 231                 return NULL;
 232
 233         /*
 234          * Rebase host offset to get the local relative number
 235          *
 236          * Note: This is by definition racy, unreliable and too simple.
 237          * Please do not copy this model anywhere. It's just a left-over
 238          * from the time we had no idea how things should look like in
 239          * the end.
 240          *
 241          * Making assumptions about a global in-kernel counter and use
 242          * that to calculate a local offset is a very broken concept. It
 243          * can only work as long as things are in strict order.
 244          *
 245          * The kernel needs to export the instance/port number of a
 246          * controller directly, without the need for rebase magic like
 247          * this. Manual driver unbind/bind, parallel hotplug/unplug will
 248          * get into the way of this "I hope it works" logic.
 249          */
 250         basenum = -1;
 251         base = strdup(udev_device_get_syspath(hostdev));
 252         if (base == NULL)
 253                 return NULL;
 254         pos = strrchr(base, '/');
 255         if (pos == NULL) {
 256                 parent = NULL;
 257                 goto out;
 258         }
 259         pos[0] = '\0';
 260         dir = opendir(base);
 261         if (dir == NULL) {
 262                 parent = NULL;
 263                 goto out;
 264         }
 265         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 266                 char *rest;
 267                 int i;
 268
 269                 if (dent->d_name[0] == '.')
 270                         continue;
 271                 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
 272                         continue;
 273                 if (!startswith(dent->d_name, "host"))
 274                         continue;
 275                 i = strtoul(&dent->d_name[4], &rest, 10);
 276                 if (rest[0] != '\0')
 277                         continue;
 278                 /*
 279                  * find the smallest number; the host really needs to export its
 280                  * own instance number per parent device; relying on the global host
 281                  * enumeration and plainly rebasing the numbers sounds unreliable
 282                  */
 283                 if (basenum == -1 || i < basenum)
 284                         basenum = i;
 285         }
 286         closedir(dir);
 287         if (basenum == -1) {
 288                 parent = NULL;
 289                 goto out;
 290         }
 291         host -= basenum;
 292
 293         path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
 294 out:
 295         free(base);
 296         return hostdev;
 297 }
 298
 299 static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char **path) {
 300         struct udev_device *hostdev;
 301         struct udev_device *vmbusdev;
 302         const char *guid_str;
 303         char *lun = NULL;
 304         char guid[38];
 305         size_t i, k;
 306
 307         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 308         if (!hostdev)
 309                 return NULL;
 310
 311         vmbusdev = udev_device_get_parent(hostdev);
 312         if (!vmbusdev)
 313                 return NULL;
 314
 315         guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
 316         if (!guid_str)
 317                 return NULL;
 318
 319         if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
 320                 return NULL;
 321
 322         for (i = 1, k = 0; i < 36; i++) {
 323                 if (guid_str[i] == '-')
 324                         continue;
 325                 guid[k++] = guid_str[i];
 326         }
 327         guid[k] = '\0';
 328
 329         format_lun_number(parent, &lun);
 330         path_prepend(path, "vmbus-%s-%s", guid, lun);
 331         free(lun);
 332         return parent;
 333 }
 334
 335 static struct udev_device *handle_scsi(struct udev_device *parent, char **path) {
 336         const char *devtype;
 337         const char *name;
 338         const char *id;
 339
 340         devtype = udev_device_get_devtype(parent);
 341         if (devtype == NULL || !streq(devtype, "scsi_device"))
 342                 return parent;
 343
 344         /* firewire */
 345         id = udev_device_get_sysattr_value(parent, "ieee1394_id");
 346         if (id != NULL) {
 347                 parent = skip_subsystem(parent, "scsi");
 348                 path_prepend(path, "ieee1394-0x%s", id);
 349                 goto out;
 350         }
 351
 352         /* scsi sysfs does not have a "subsystem" for the transport */
 353         name = udev_device_get_syspath(parent);
 354
 355         if (strstr(name, "/rport-") != NULL) {
 356                 parent = handle_scsi_fibre_channel(parent, path);
 357                 goto out;
 358         }
 359
 360         if (strstr(name, "/end_device-") != NULL) {
 361                 parent = handle_scsi_sas(parent, path);
 362                 goto out;
 363         }
 364
 365         if (strstr(name, "/session") != NULL) {
 366                 parent = handle_scsi_iscsi(parent, path);
 367                 goto out;
 368         }
 369
 370         /*
 371          * We do not support the ATA transport class, it uses global counters
 372          * to name the ata devices which numbers spread across multiple
 373          * controllers.
 374          *
 375          * The real link numbers are not exported. Also, possible chains of ports
 376          * behind port multipliers cannot be composed that way.
 377          *
 378          * Until all that is solved at the kernel level, there are no by-path/
 379          * links for ATA devices.
 380          */
 381         if (strstr(name, "/ata") != NULL) {
 382                 parent = NULL;
 383                 goto out;
 384         }
 385
 386         if (strstr(name, "/vmbus_") != NULL) {
 387                 parent = handle_scsi_hyperv(parent, path);
 388                 goto out;
 389         }
 390
 391         parent = handle_scsi_default(parent, path);
 392 out:
 393         return parent;
 394 }
 395
 396 static struct udev_device *handle_cciss(struct udev_device *parent, char **path) {
 397         const char *str;
 398         unsigned int controller, disk;
 399
 400         str = udev_device_get_sysname(parent);
 401         if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
 402                 return NULL;
 403
 404         path_prepend(path, "cciss-disk%u", disk);
 405         parent = skip_subsystem(parent, "cciss");
 406         return parent;
 407 }
 408
 409 static void handle_scsi_tape(struct udev_device *dev, char **path) {
 410         const char *name;
 411
 412         /* must be the last device in the syspath */
 413         if (*path != NULL)
 414                 return;
 415
 416         name = udev_device_get_sysname(dev);
 417         if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
 418                 path_prepend(path, "nst%c", name[3]);
 419         else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
 420                 path_prepend(path, "st%c", name[2]);
 421 }
 422
 423 static struct udev_device *handle_usb(struct udev_device *parent, char **path) {
 424         const char *devtype;
 425         const char *str;
 426         const char *port;
 427
 428         devtype = udev_device_get_devtype(parent);
 429         if (devtype == NULL)
 430                 return parent;
 431         if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
 432                 return parent;
 433
 434         str = udev_device_get_sysname(parent);
 435         port = strchr(str, '-');
 436         if (port == NULL)
 437                 return parent;
 438         port++;
 439
 440         parent = skip_subsystem(parent, "usb");
 441         path_prepend(path, "usb-0:%s", port);
 442         return parent;
 443 }
 444
 445 static struct udev_device *handle_bcma(struct udev_device *parent, char **path) {
 446         const char *sysname;
 447         unsigned int core;
 448
 449         sysname = udev_device_get_sysname(parent);
 450         if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
 451                 return NULL;
 452
 453         path_prepend(path, "bcma-%u", core);
 454         return parent;
 455 }
 456
 457 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path) {
 458         struct udev_device *scsi_dev;
 459
 460         scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
 461         if (scsi_dev != NULL) {
 462                 const char *wwpn;
 463                 const char *lun;
 464                 const char *hba_id;
 465
 466                 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
 467                 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
 468                 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
 469                 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
 470                         path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
 471                         goto out;
 472                 }
 473         }
 474
 475         path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
 476 out:
 477         parent = skip_subsystem(parent, "ccw");
 478         return parent;
 479 }
 480
 481 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test) {
 482         struct udev_device *parent;
 483         char *path = NULL;
 484         bool supported_transport = false;
 485         bool supported_parent = false;
 486
 487         /* S390 ccw bus */
 488         parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
 489         if (parent != NULL) {
 490                 handle_ccw(parent, dev, &path);
 491                 goto out;
 492         }
 493
 494         /* walk up the chain of devices and compose path */
 495         parent = dev;
 496         while (parent != NULL) {
 497                 const char *subsys;
 498
 499                 subsys = udev_device_get_subsystem(parent);
 500                 if (subsys == NULL) {
 501                         ;
 502                 } else if (streq(subsys, "scsi_tape")) {
 503                         handle_scsi_tape(parent, &path);
 504                 } else if (streq(subsys, "scsi")) {
 505                         parent = handle_scsi(parent, &path);
 506                         supported_transport = true;
 507                 } else if (streq(subsys, "cciss")) {
 508                         parent = handle_cciss(parent, &path);
 509                         supported_transport = true;
 510                 } else if (streq(subsys, "usb")) {
 511                         parent = handle_usb(parent, &path);
 512                         supported_transport = true;
 513                 } else if (streq(subsys, "bcma")) {
 514                         parent = handle_bcma(parent, &path);
 515                         supported_transport = true;
 516                 } else if (streq(subsys, "serio")) {
 517                         path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
 518                         parent = skip_subsystem(parent, "serio");
 519                 } else if (streq(subsys, "pci")) {
 520                         path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
 521                         parent = skip_subsystem(parent, "pci");
 522                         supported_parent = true;
 523                 } else if (streq(subsys, "platform")) {
 524                         path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
 525                         parent = skip_subsystem(parent, "platform");
 526                         supported_transport = true;
 527                         supported_parent = true;
 528                 } else if (streq(subsys, "acpi")) {
 529                         path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
 530                         parent = skip_subsystem(parent, "acpi");
 531                         supported_parent = true;
 532                 } else if (streq(subsys, "xen")) {
 533                         path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
 534                         parent = skip_subsystem(parent, "xen");
 535                         supported_parent = true;
 536                 } else if (streq(subsys, "scm")) {
 537                         path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
 538                         parent = skip_subsystem(parent, "scm");
 539                         supported_transport = true;
 540                         supported_parent = true;
 541                 }
 542
 543                 parent = udev_device_get_parent(parent);
 544         }
 545
 546         /*
 547          * Do return devices with have an unknown type of parent device, they
 548          * might produce conflicting IDs below multiple independent parent
 549          * devices.
 550          */
 551         if (!supported_parent) {
 552                 free(path);
 553                 path = NULL;
 554         }
 555
 556         /*
 557          * Do not return a have-only a single-parent block devices, some
 558          * have entire hidden buses behind it, and not create predictable
 559          * IDs that way.
 560          */
 561         if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
 562                 free(path);
 563                 path = NULL;
 564         }
 565
 566 out:
 567         if (path != NULL) {
 568                 char tag[UTIL_NAME_SIZE];
 569                 size_t i;
 570                 const char *p;
 571
 572                 /* compose valid udev tag name */
 573                 for (p = path, i = 0; *p; p++) {
 574                         if ((*p >= '0' && *p <= '9') ||
 575                             (*p >= 'A' && *p <= 'Z') ||
 576                             (*p >= 'a' && *p <= 'z') ||
 577                             *p == '-') {
 578                                 tag[i++] = *p;
 579                                 continue;
 580                         }
 581
 582                         /* skip all leading '_' */
 583                         if (i == 0)
 584                                 continue;
 585
 586                         /* avoid second '_' */
 587                         if (tag[i-1] == '_')
 588                                 continue;
 589
 590                         tag[i++] = '_';
 591                 }
 592                 /* strip trailing '_' */
 593                 while (i > 0 && tag[i-1] == '_')
 594                         i--;
 595                 tag[i] = '\0';
 596
 597                 udev_builtin_add_property(dev, test, "ID_PATH", path);
 598                 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 599                 free(path);
 600                 return EXIT_SUCCESS;
 601         }
 602         return EXIT_FAILURE;
 603 }
 604
 605 const struct udev_builtin udev_builtin_path_id = {
 606         .name = "path_id",
 607         .cmd = builtin_path_id,
 608         .help = "compose persistent device path",
 609         .run_once = true,
 610 };