src/udev/udev-builtin-path_id.c

   1 /*
   2  * compose persistent device path
   3  *
   4  * Copyright (C) 2009-2011 Kay Sievers <kay.sievers@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 static int path_prepend(char **path, const char *fmt, ...)
  36 {
  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 {
  69         unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
  70
  71         /* address method 0, peripheral device addressing with bus id of zero */
  72         if (lun < 256)
  73                 return path_prepend(path, "lun-%d", lun);
  74         /* handle all other lun addressing methods by using a variant of the original lun format */
  75         return path_prepend(path, "lun-0x%04x%04x00000000", (lun & 0xffff), (lun >> 16) & 0xffff);
  76 }
  77
  78 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys)
  79 {
  80         struct udev_device *parent = dev;
  81
  82         while (parent != NULL) {
  83                 const char *subsystem;
  84
  85                 subsystem = udev_device_get_subsystem(parent);
  86                 if (subsystem == NULL || strcmp(subsystem, subsys) != 0)
  87                         break;
  88                 dev = parent;
  89                 parent = udev_device_get_parent(parent);
  90         }
  91         return dev;
  92 }
  93
  94 static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent, char **path)
  95 {
  96         struct udev *udev  = udev_device_get_udev(parent);
  97         struct udev_device *targetdev;
  98         struct udev_device *fcdev = NULL;
  99         const char *port;
 100         char *lun = NULL;;
 101
 102         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 103         if (targetdev == NULL)
 104                 return NULL;
 105
 106         fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
 107         if (fcdev == NULL)
 108                 return NULL;
 109         port = udev_device_get_sysattr_value(fcdev, "port_name");
 110         if (port == NULL) {
 111                 parent = NULL;
 112                 goto out;
 113         }
 114
 115         format_lun_number(parent, &lun);
 116         path_prepend(path, "fc-%s-%s", port, lun);
 117         if (lun)
 118                 free(lun);
 119 out:
 120         udev_device_unref(fcdev);
 121         return parent;
 122 }
 123
 124 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
 125 {
 126         struct udev *udev  = udev_device_get_udev(parent);
 127         struct udev_device *targetdev;
 128         struct udev_device *target_parent;
 129         struct udev_device *sasdev;
 130         const char *sas_address;
 131         char *lun = NULL;
 132
 133         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 134         if (targetdev == NULL)
 135                 return NULL;
 136
 137         target_parent = udev_device_get_parent(targetdev);
 138         if (target_parent == NULL)
 139                 return NULL;
 140
 141         sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
 142                                 udev_device_get_sysname(target_parent));
 143         if (sasdev == NULL)
 144                 return NULL;
 145
 146         sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
 147         if (sas_address == NULL) {
 148                 parent = NULL;
 149                 goto out;
 150         }
 151
 152         format_lun_number(parent, &lun);
 153         path_prepend(path, "sas-%s-%s", sas_address, lun);
 154         if (lun)
 155                 free(lun);
 156 out:
 157         udev_device_unref(sasdev);
 158         return parent;
 159 }
 160
 161 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path)
 162 {
 163         struct udev *udev  = udev_device_get_udev(parent);
 164         struct udev_device *transportdev;
 165         struct udev_device *sessiondev = NULL;
 166         const char *target;
 167         char *connname;
 168         struct udev_device *conndev = NULL;
 169         const char *addr;
 170         const char *port;
 171         char *lun = NULL;
 172
 173         /* find iscsi session */
 174         transportdev = parent;
 175         for (;;) {
 176                 transportdev = udev_device_get_parent(transportdev);
 177                 if (transportdev == NULL)
 178                         return NULL;
 179                 if (startswith(udev_device_get_sysname(transportdev), "session"))
 180                         break;
 181         }
 182
 183         /* find iscsi session device */
 184         sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
 185         if (sessiondev == NULL)
 186                 return NULL;
 187         target = udev_device_get_sysattr_value(sessiondev, "targetname");
 188         if (target == NULL) {
 189                 parent = NULL;
 190                 goto out;
 191         }
 192
 193         if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
 194                 parent = NULL;
 195                 goto out;
 196         }
 197         conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
 198         free(connname);
 199         if (conndev == NULL) {
 200                 parent = NULL;
 201                 goto out;
 202         }
 203         addr = udev_device_get_sysattr_value(conndev, "persistent_address");
 204         port = udev_device_get_sysattr_value(conndev, "persistent_port");
 205         if (addr == NULL || port == NULL) {
 206                 parent = NULL;
 207                 goto out;
 208         }
 209
 210         format_lun_number(parent, &lun);
 211         path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 212         if (lun)
 213                 free(lun);
 214 out:
 215         udev_device_unref(sessiondev);
 216         udev_device_unref(conndev);
 217         return parent;
 218 }
 219
 220 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path)
 221 {
 222         struct udev_device *hostdev;
 223         int host, bus, target, lun;
 224         const char *name;
 225         char *base;
 226         char *pos;
 227         DIR *dir;
 228         struct dirent *dent;
 229         int basenum;
 230
 231         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 232         if (hostdev == NULL)
 233                 return NULL;
 234
 235         name = udev_device_get_sysname(parent);
 236         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 237                 return NULL;
 238
 239         /*
 240          * Rebase host offset to get the local relative number
 241          *
 242          * Note: This is by definition racy, unreliable and too simple.
 243          * Please do not copy this model anywhere. It's just a left-over
 244          * from the time we had no idea how things should look like in
 245          * the end.
 246          *
 247          * Making assumptions about a global in-kernel counter and use
 248          * that to calculate a local offset is a very broken concept. It
 249          * can only work as long as things are in strict order.
 250          *
 251          * The kernel needs to export the instance/port number of a
 252          * controller directly, without the need for rebase magic like
 253          * this. Manual driver unbind/bind, parallel hotplug/unplug will
 254          * get into the way of this "I hope it works" logic.
 255          */
 256         basenum = -1;
 257         base = strdup(udev_device_get_syspath(hostdev));
 258         if (base == NULL)
 259                 return NULL;
 260         pos = strrchr(base, '/');
 261         if (pos == NULL) {
 262                 parent = NULL;
 263                 goto out;
 264         }
 265         pos[0] = '\0';
 266         dir = opendir(base);
 267         if (dir == NULL) {
 268                 parent = NULL;
 269                 goto out;
 270         }
 271         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 272                 char *rest;
 273                 int i;
 274
 275                 if (dent->d_name[0] == '.')
 276                         continue;
 277                 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
 278                         continue;
 279                 if (!startswith(dent->d_name, "host"))
 280                         continue;
 281                 i = strtoul(&dent->d_name[4], &rest, 10);
 282                 if (rest[0] != '\0')
 283                         continue;
 284                 /*
 285                  * find the smallest number; the host really needs to export its
 286                  * own instance number per parent device; relying on the global host
 287                  * enumeration and plainly rebasing the numbers sounds unreliable
 288                  */
 289                 if (basenum == -1 || i < basenum)
 290                         basenum = i;
 291         }
 292         closedir(dir);
 293         if (basenum == -1) {
 294                 parent = NULL;
 295                 goto out;
 296         }
 297         host -= basenum;
 298
 299         path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
 300 out:
 301         free(base);
 302         return hostdev;
 303 }
 304
 305 static struct udev_device *handle_scsi(struct udev_device *parent, char **path)
 306 {
 307         const char *devtype;
 308         const char *name;
 309         const char *id;
 310
 311         devtype = udev_device_get_devtype(parent);
 312         if (devtype == NULL || strcmp(devtype, "scsi_device") != 0)
 313                 return parent;
 314
 315         /* firewire */
 316         id = udev_device_get_sysattr_value(parent, "ieee1394_id");
 317         if (id != NULL) {
 318                 parent = skip_subsystem(parent, "scsi");
 319                 path_prepend(path, "ieee1394-0x%s", id);
 320                 goto out;
 321         }
 322
 323         /* lousy scsi sysfs does not have a "subsystem" for the transport */
 324         name = udev_device_get_syspath(parent);
 325
 326         if (strstr(name, "/rport-") != NULL) {
 327                 parent = handle_scsi_fibre_channel(parent, path);
 328                 goto out;
 329         }
 330
 331         if (strstr(name, "/end_device-") != NULL) {
 332                 parent = handle_scsi_sas(parent, path);
 333                 goto out;
 334         }
 335
 336         if (strstr(name, "/session") != NULL) {
 337                 parent = handle_scsi_iscsi(parent, path);
 338                 goto out;
 339         }
 340
 341         /*
 342          * We do not support the ATA transport class, it creates duplicated link
 343          * names as the fake SCSI host adapters are all separated, they are all
 344          * re-based as host == 0. ATA should just stop faking two duplicated
 345          * hierarchies for a single topology and leave the SCSI stuff alone;
 346          * until that happens, there are no by-path/ links for ATA devices behind
 347          * an ATA transport class.
 348          */
 349         if (strstr(name, "/ata") != NULL) {
 350                 parent = NULL;
 351                 goto out;
 352         }
 353
 354         parent = handle_scsi_default(parent, path);
 355 out:
 356         return parent;
 357 }
 358
 359 static struct udev_device *handle_cciss(struct udev_device *parent, char **path)
 360 {
 361         const char *str;
 362         unsigned int controller, disk;
 363
 364         str = udev_device_get_sysname(parent);
 365         if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
 366                 return NULL;
 367
 368         path_prepend(path, "cciss-disk%u", disk);
 369         parent = skip_subsystem(parent, "cciss");
 370         return parent;
 371 }
 372
 373 static void handle_scsi_tape(struct udev_device *dev, char **path)
 374 {
 375         const char *name;
 376
 377         /* must be the last device in the syspath */
 378         if (*path != NULL)
 379                 return;
 380
 381         name = udev_device_get_sysname(dev);
 382         if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
 383                 path_prepend(path, "nst%c", name[3]);
 384         else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
 385                 path_prepend(path, "st%c", name[2]);
 386 }
 387
 388 static struct udev_device *handle_usb(struct udev_device *parent, char **path)
 389 {
 390         const char *devtype;
 391         const char *str;
 392         const char *port;
 393
 394         devtype = udev_device_get_devtype(parent);
 395         if (devtype == NULL)
 396                 return parent;
 397         if (strcmp(devtype, "usb_interface") != 0 && strcmp(devtype, "usb_device") != 0)
 398                 return parent;
 399
 400         str = udev_device_get_sysname(parent);
 401         port = strchr(str, '-');
 402         if (port == NULL)
 403                 return parent;
 404         port++;
 405
 406         parent = skip_subsystem(parent, "usb");
 407         path_prepend(path, "usb-0:%s", port);
 408         return parent;
 409 }
 410
 411 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path)
 412 {
 413         struct udev_device *scsi_dev;
 414
 415         scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
 416         if (scsi_dev != NULL) {
 417                 const char *wwpn;
 418                 const char *lun;
 419                 const char *hba_id;
 420
 421                 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
 422                 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
 423                 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
 424                 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
 425                         path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
 426                         goto out;
 427                 }
 428         }
 429
 430         path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
 431 out:
 432         parent = skip_subsystem(parent, "ccw");
 433         return parent;
 434 }
 435
 436 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test)
 437 {
 438         struct udev_device *parent;
 439         char *path = NULL;
 440         bool some_transport = false;
 441
 442         /* S390 ccw bus */
 443         parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
 444         if (parent != NULL) {
 445                 handle_ccw(parent, dev, &path);
 446                 goto out;
 447         }
 448
 449         /* walk up the chain of devices and compose path */
 450         parent = dev;
 451         while (parent != NULL) {
 452                 const char *subsys;
 453
 454                 subsys = udev_device_get_subsystem(parent);
 455                 if (subsys == NULL) {
 456                         ;
 457                 } else if (strcmp(subsys, "scsi_tape") == 0) {
 458                         handle_scsi_tape(parent, &path);
 459                 } else if (strcmp(subsys, "scsi") == 0) {
 460                         parent = handle_scsi(parent, &path);
 461                         some_transport = true;
 462                 } else if (strcmp(subsys, "cciss") == 0) {
 463                         parent = handle_cciss(parent, &path);
 464                         some_transport = true;
 465                 } else if (strcmp(subsys, "usb") == 0) {
 466                         parent = handle_usb(parent, &path);
 467                         some_transport = true;
 468                 } else if (strcmp(subsys, "serio") == 0) {
 469                         path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
 470                         parent = skip_subsystem(parent, "serio");
 471                 } else if (strcmp(subsys, "pci") == 0) {
 472                         path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
 473                         parent = skip_subsystem(parent, "pci");
 474                 } else if (strcmp(subsys, "platform") == 0) {
 475                         path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
 476                         parent = skip_subsystem(parent, "platform");
 477                         some_transport = true;
 478                 } else if (strcmp(subsys, "acpi") == 0) {
 479                         path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
 480                         parent = skip_subsystem(parent, "acpi");
 481                 } else if (strcmp(subsys, "xen") == 0) {
 482                         path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
 483                         parent = skip_subsystem(parent, "xen");
 484                 } else if (strcmp(subsys, "virtio") == 0) {
 485                         path_prepend(&path, "virtio-pci-%s", udev_device_get_sysname(parent));
 486                         parent = skip_subsystem(parent, "virtio");
 487                 }
 488
 489                 parent = udev_device_get_parent(parent);
 490         }
 491
 492         /*
 493          * Do not return a single-parent-device-only for block
 494          * devices, they might have entire buses behind it which
 495          * do not get unique IDs only by using the parent device.
 496          */
 497         if (!some_transport && streq(udev_device_get_subsystem(dev), "block")) {
 498                 free(path);
 499                 path = NULL;
 500         }
 501
 502 out:
 503         if (path != NULL) {
 504                 char tag[UTIL_NAME_SIZE];
 505                 size_t i;
 506                 const char *p;
 507
 508                 /* compose valid udev tag name */
 509                 for (p = path, i = 0; *p; p++) {
 510                         if ((*p >= '0' && *p <= '9') ||
 511                             (*p >= 'A' && *p <= 'Z') ||
 512                             (*p >= 'a' && *p <= 'z') ||
 513                             *p == '-') {
 514                                 tag[i++] = *p;
 515                                 continue;
 516                         }
 517
 518                         /* skip all leading '_' */
 519                         if (i == 0)
 520                                 continue;
 521
 522                         /* avoid second '_' */
 523                         if (tag[i-1] == '_')
 524                                 continue;
 525
 526                         tag[i++] = '_';
 527                 }
 528                 /* strip trailing '_' */
 529                 while (i > 0 && tag[i-1] == '_')
 530                         i--;
 531                 tag[i] = '\0';
 532
 533                 udev_builtin_add_property(dev, test, "ID_PATH", path);
 534                 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 535                 free(path);
 536                 return EXIT_SUCCESS;
 537         }
 538         return EXIT_FAILURE;
 539 }
 540
 541 const struct udev_builtin udev_builtin_path_id = {
 542         .name = "path_id",
 543         .cmd = builtin_path_id,
 544         .help = "compose persistent device path",
 545         .run_once = true,
 546 };