src/udev/udev-builtin-path_id.c

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * compose persistent device path
   4  *
   5  * Logic based on Hannes Reinecke's shell script.
   6  */
   7
   8 #include <ctype.h>
   9 #include <errno.h>
  10 #include <fcntl.h>
  11 #include <getopt.h>
  12 #include <linux/usb/ch11.h>
  13 #include <stdarg.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16
  17 #include "alloc-util.h"
  18 #include "device-util.h"
  19 #include "dirent-util.h"
  20 #include "fd-util.h"
  21 #include "parse-util.h"
  22 #include "string-util.h"
  23 #include "strv.h"
  24 #include "sysexits.h"
  25 #include "udev-builtin.h"
  26 #include "udev-util.h"
  27
  28 _printf_(2,3)
  29 static void path_prepend(char **path, const char *fmt, ...) {
  30         va_list va;
  31         _cleanup_free_ char *pre = NULL;
  32         int r;
  33
  34         va_start(va, fmt);
  35         r = vasprintf(&pre, fmt, va);
  36         va_end(va);
  37         if (r < 0) {
  38                 log_oom();
  39                 exit(EX_OSERR);
  40         }
  41
  42         if (*path) {
  43                 char *new;
  44
  45                 new = strjoin(pre, "-", *path);
  46                 if (!new) {
  47                         log_oom();
  48                         exit(EX_OSERR);
  49                 }
  50
  51                 free_and_replace(*path, new);
  52         } else
  53                 *path = TAKE_PTR(pre);
  54 }
  55
  56 /*
  57 ** Linux only supports 32 bit luns.
  58 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
  59 */
  60 static int format_lun_number(sd_device *dev, char **path) {
  61         const char *sysnum;
  62         unsigned long lun;
  63         int r;
  64
  65         r = sd_device_get_sysnum(dev, &sysnum);
  66         if (r < 0)
  67                 return r;
  68         if (!sysnum)
  69                 return -ENOENT;
  70
  71         r = safe_atolu_full(sysnum, 10, &lun);
  72         if (r < 0)
  73                 return r;
  74         if (lun < 256)
  75                 /* address method 0, peripheral device addressing with bus id of zero */
  76                 path_prepend(path, "lun-%lu", lun);
  77         else
  78                 /* handle all other lun addressing methods by using a variant of the original lun format */
  79                 path_prepend(path, "lun-0x%04lx%04lx00000000", lun & 0xffff, (lun >> 16) & 0xffff);
  80
  81         return 0;
  82 }
  83
  84 static sd_device *skip_subsystem(sd_device *dev, const char *subsys) {
  85         sd_device *parent;
  86
  87         assert(dev);
  88         assert(subsys);
  89
  90         /* Unlike the function name, this drops multiple parent devices EXCEPT FOR THE LAST ONE.
  91          * The last one will be dropped at the end of the loop in builtin_path_id().
  92          * E.g.
  93          * Input:  /sys/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1:1.0
  94          * Output: /sys/devices/pci0000:00/0000:00:14.0/usb1
  95          */
  96
  97         for (parent = dev; ; ) {
  98                 if (!device_in_subsystem(parent, subsys))
  99                         break;
 100
 101                 dev = parent;
 102                 if (sd_device_get_parent(dev, &parent) < 0)
 103                         break;
 104         }
 105
 106         return dev;
 107 }
 108
 109 static sd_device *handle_scsi_fibre_channel(sd_device *parent, char **path) {
 110         sd_device *targetdev;
 111         _cleanup_(sd_device_unrefp) sd_device *fcdev = NULL;
 112         const char *port, *sysname;
 113         _cleanup_free_ char *lun = NULL;
 114
 115         assert(parent);
 116         assert(path);
 117
 118         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target", &targetdev) < 0)
 119                 return NULL;
 120         if (sd_device_get_sysname(targetdev, &sysname) < 0)
 121                 return NULL;
 122         if (sd_device_new_from_subsystem_sysname(&fcdev, "fc_transport", sysname) < 0)
 123                 return NULL;
 124         if (sd_device_get_sysattr_value(fcdev, "port_name", &port) < 0)
 125                 return NULL;
 126
 127         format_lun_number(parent, &lun);
 128         path_prepend(path, "fc-%s-%s", port, lun);
 129         return parent;
 130 }
 131
 132 static sd_device *handle_scsi_sas_wide_port(sd_device *parent, char **path) {
 133         sd_device *targetdev, *target_parent;
 134         _cleanup_(sd_device_unrefp) sd_device *sasdev = NULL;
 135         const char *sas_address, *sysname;
 136         _cleanup_free_ char *lun = NULL;
 137
 138         assert(parent);
 139         assert(path);
 140
 141         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target", &targetdev) < 0)
 142                 return NULL;
 143         if (sd_device_get_parent(targetdev, &target_parent) < 0)
 144                 return NULL;
 145         if (sd_device_get_sysname(target_parent, &sysname) < 0)
 146                 return NULL;
 147         if (sd_device_new_from_subsystem_sysname(&sasdev, "sas_device", sysname) < 0)
 148                 return NULL;
 149         if (sd_device_get_sysattr_value(sasdev, "sas_address", &sas_address) < 0)
 150                 return NULL;
 151
 152         format_lun_number(parent, &lun);
 153         path_prepend(path, "sas-%s-%s", sas_address, lun);
 154         return parent;
 155 }
 156
 157 static sd_device *handle_scsi_sas(sd_device *parent, char **path) {
 158         sd_device *targetdev, *target_parent, *port, *expander;
 159         _cleanup_(sd_device_unrefp) sd_device *target_sasdev = NULL, *expander_sasdev = NULL, *port_sasdev = NULL;
 160         const char *sas_address = NULL;
 161         const char *phy_id;
 162         const char *phy_count, *sysname;
 163         _cleanup_free_ char *lun = NULL;
 164
 165         assert(parent);
 166         assert(path);
 167
 168         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target", &targetdev) < 0)
 169                 return NULL;
 170         if (sd_device_get_parent(targetdev, &target_parent) < 0)
 171                 return NULL;
 172         if (sd_device_get_sysname(target_parent, &sysname) < 0)
 173                 return NULL;
 174         /* Get sas device */
 175         if (sd_device_new_from_subsystem_sysname(&target_sasdev, "sas_device", sysname) < 0)
 176                 return NULL;
 177         /* The next parent is sas port */
 178         if (sd_device_get_parent(target_parent, &port) < 0)
 179                 return NULL;
 180         if (sd_device_get_sysname(port, &sysname) < 0)
 181                 return NULL;
 182         /* Get port device */
 183         if (sd_device_new_from_subsystem_sysname(&port_sasdev, "sas_port", sysname) < 0)
 184                 return NULL;
 185         if (sd_device_get_sysattr_value(port_sasdev, "num_phys", &phy_count) < 0)
 186                 return NULL;
 187
 188         /* Check if we are simple disk */
 189         if (strncmp(phy_count, "1", 2) != 0)
 190                 return handle_scsi_sas_wide_port(parent, path);
 191
 192         /* Get connected phy */
 193         if (sd_device_get_sysattr_value(target_sasdev, "phy_identifier", &phy_id) < 0)
 194                 return NULL;
 195
 196         /* The port's parent is either hba or expander */
 197         if (sd_device_get_parent(port, &expander) < 0)
 198                 return NULL;
 199
 200         if (sd_device_get_sysname(expander, &sysname) < 0)
 201                 return NULL;
 202         /* Get expander device */
 203         if (sd_device_new_from_subsystem_sysname(&expander_sasdev, "sas_device", sysname) >= 0) {
 204                 /* Get expander's address */
 205                 if (sd_device_get_sysattr_value(expander_sasdev, "sas_address", &sas_address) < 0)
 206                         return NULL;
 207         }
 208
 209         format_lun_number(parent, &lun);
 210         if (sas_address)
 211                  path_prepend(path, "sas-exp%s-phy%s-%s", sas_address, phy_id, lun);
 212         else
 213                  path_prepend(path, "sas-phy%s-%s", phy_id, lun);
 214
 215         return parent;
 216 }
 217
 218 static sd_device *handle_scsi_iscsi(sd_device *parent, char **path) {
 219         sd_device *transportdev;
 220         _cleanup_(sd_device_unrefp) sd_device *sessiondev = NULL, *conndev = NULL;
 221         const char *target, *connname, *addr, *port;
 222         _cleanup_free_ char *lun = NULL;
 223         const char *sysname, *sysnum;
 224
 225         assert(parent);
 226         assert(path);
 227
 228         /* find iscsi session */
 229         for (transportdev = parent; ; ) {
 230
 231                 if (sd_device_get_parent(transportdev, &transportdev) < 0)
 232                         return NULL;
 233                 if (sd_device_get_sysname(transportdev, &sysname) < 0)
 234                         return NULL;
 235                 if (startswith(sysname, "session"))
 236                         break;
 237         }
 238
 239         /* find iscsi session device */
 240         if (sd_device_new_from_subsystem_sysname(&sessiondev, "iscsi_session", sysname) < 0)
 241                 return NULL;
 242
 243         if (sd_device_get_sysattr_value(sessiondev, "targetname", &target) < 0)
 244                 return NULL;
 245
 246         if (sd_device_get_sysnum(transportdev, &sysnum) < 0 || !sysnum)
 247                 return NULL;
 248         connname = strjoina("connection", sysnum, ":0");
 249         if (sd_device_new_from_subsystem_sysname(&conndev, "iscsi_connection", connname) < 0)
 250                 return NULL;
 251
 252         if (sd_device_get_sysattr_value(conndev, "persistent_address", &addr) < 0)
 253                 return NULL;
 254         if (sd_device_get_sysattr_value(conndev, "persistent_port", &port) < 0)
 255                 return NULL;
 256
 257         format_lun_number(parent, &lun);
 258         path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 259         return parent;
 260 }
 261
 262 static sd_device *handle_scsi_ata(sd_device *parent, char **path, char **compat_path) {
 263         sd_device *targetdev, *target_parent;
 264         _cleanup_(sd_device_unrefp) sd_device *atadev = NULL;
 265         const char *port_no, *sysname, *name;
 266         unsigned host, bus, target, lun;
 267
 268         assert(parent);
 269         assert(path);
 270
 271         if (sd_device_get_sysname(parent, &name) < 0)
 272                 return NULL;
 273         if (sscanf(name, "%u:%u:%u:%u", &host, &bus, &target, &lun) != 4)
 274                 return NULL;
 275
 276         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host", &targetdev) < 0)
 277                 return NULL;
 278
 279         if (sd_device_get_parent(targetdev, &target_parent) < 0)
 280                 return NULL;
 281
 282         if (sd_device_get_sysname(target_parent, &sysname) < 0)
 283                 return NULL;
 284         if (sd_device_new_from_subsystem_sysname(&atadev, "ata_port", sysname) < 0)
 285                 return NULL;
 286
 287         if (sd_device_get_sysattr_value(atadev, "port_no", &port_no) < 0)
 288                 return NULL;
 289
 290         if (bus != 0)
 291                 /* Devices behind port multiplier have a bus != 0 */
 292                 path_prepend(path, "ata-%s.%u.0", port_no, bus);
 293         else
 294                 /* Master/slave are distinguished by target id */
 295                 path_prepend(path, "ata-%s.%u", port_no, target);
 296
 297         /* old compatible persistent link for ATA devices */
 298         if (compat_path)
 299                 path_prepend(compat_path, "ata-%s", port_no);
 300
 301         return parent;
 302 }
 303
 304 static sd_device *handle_scsi_default(sd_device *parent, char **path) {
 305         sd_device *hostdev;
 306         int host, bus, target, lun;
 307         const char *name, *base, *pos;
 308         _cleanup_closedir_ DIR *dir = NULL;
 309         int basenum = -1;
 310
 311         assert(parent);
 312         assert(path);
 313
 314         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host", &hostdev) < 0)
 315                 return NULL;
 316
 317         if (sd_device_get_sysname(parent, &name) < 0)
 318                 return NULL;
 319         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 320                 return NULL;
 321
 322         /*
 323          * Rebase host offset to get the local relative number
 324          *
 325          * Note: This is by definition racy, unreliable and too simple.
 326          * Please do not copy this model anywhere. It's just a left-over
 327          * from the time we had no idea how things should look like in
 328          * the end.
 329          *
 330          * Making assumptions about a global in-kernel counter and use
 331          * that to calculate a local offset is a very broken concept. It
 332          * can only work as long as things are in strict order.
 333          *
 334          * The kernel needs to export the instance/port number of a
 335          * controller directly, without the need for rebase magic like
 336          * this. Manual driver unbind/bind, parallel hotplug/unplug will
 337          * get into the way of this "I hope it works" logic.
 338          */
 339
 340         if (sd_device_get_syspath(hostdev, &base) < 0)
 341                 return NULL;
 342         pos = strrchr(base, '/');
 343         if (!pos)
 344                 return NULL;
 345
 346         base = strndupa_safe(base, pos - base);
 347         dir = opendir(base);
 348         if (!dir)
 349                 return NULL;
 350
 351         FOREACH_DIRENT_ALL(de, dir, break) {
 352                 unsigned i;
 353
 354                 if (de->d_name[0] == '.')
 355                         continue;
 356                 if (!IN_SET(de->d_type, DT_DIR, DT_LNK))
 357                         continue;
 358                 if (!startswith(de->d_name, "host"))
 359                         continue;
 360                 if (safe_atou_full(&de->d_name[4], 10, &i) < 0)
 361                         continue;
 362                 /*
 363                  * find the smallest number; the host really needs to export its
 364                  * own instance number per parent device; relying on the global host
 365                  * enumeration and plainly rebasing the numbers sounds unreliable
 366                  */
 367                 if (basenum == -1 || (int) i < basenum)
 368                         basenum = i;
 369         }
 370         if (basenum == -1)
 371                 return hostdev;
 372         host -= basenum;
 373
 374         path_prepend(path, "scsi-%i:%i:%i:%i", host, bus, target, lun);
 375         return hostdev;
 376 }
 377
 378 static sd_device *handle_scsi_hyperv(sd_device *parent, char **path, size_t guid_str_len) {
 379         sd_device *hostdev;
 380         sd_device *vmbusdev;
 381         const char *guid_str;
 382         _cleanup_free_ char *lun = NULL;
 383         char guid[39];
 384
 385         assert(parent);
 386         assert(path);
 387         assert(guid_str_len < sizeof(guid));
 388
 389         if (sd_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host", &hostdev) < 0)
 390                 return NULL;
 391
 392         if (sd_device_get_parent(hostdev, &vmbusdev) < 0)
 393                 return NULL;
 394
 395         if (sd_device_get_sysattr_value(vmbusdev, "device_id", &guid_str) < 0)
 396                 return NULL;
 397
 398         if (strlen(guid_str) < guid_str_len || guid_str[0] != '{' || guid_str[guid_str_len-1] != '}')
 399                 return NULL;
 400
 401         size_t k = 0;
 402         for (size_t i = 1; i < guid_str_len-1; i++) {
 403                 if (guid_str[i] == '-')
 404                         continue;
 405                 guid[k++] = guid_str[i];
 406         }
 407         guid[k] = '\0';
 408
 409         format_lun_number(parent, &lun);
 410         path_prepend(path, "vmbus-%s-%s", guid, lun);
 411         return parent;
 412 }
 413
 414 static sd_device *handle_scsi(sd_device *parent, char **path, char **compat_path, bool *supported_parent) {
 415         const char *id, *name;
 416
 417         if (!device_is_devtype(parent, "scsi_device"))
 418                 return parent;
 419
 420         /* firewire */
 421         if (sd_device_get_sysattr_value(parent, "ieee1394_id", &id) >= 0) {
 422                 path_prepend(path, "ieee1394-0x%s", id);
 423                 *supported_parent = true;
 424                 return skip_subsystem(parent, "scsi");
 425         }
 426
 427         /* scsi sysfs does not have a "subsystem" for the transport */
 428         if (sd_device_get_syspath(parent, &name) < 0)
 429                 return NULL;
 430
 431         if (strstr(name, "/rport-")) {
 432                 *supported_parent = true;
 433                 return handle_scsi_fibre_channel(parent, path);
 434         }
 435
 436         if (strstr(name, "/end_device-")) {
 437                 *supported_parent = true;
 438                 return handle_scsi_sas(parent, path);
 439         }
 440
 441         if (strstr(name, "/session")) {
 442                 *supported_parent = true;
 443                 return handle_scsi_iscsi(parent, path);
 444         }
 445
 446         if (strstr(name, "/ata"))
 447                 return handle_scsi_ata(parent, path, compat_path);
 448
 449         if (strstr(name, "/vmbus_"))
 450                 return handle_scsi_hyperv(parent, path, 37);
 451         else if (strstr(name, "/VMBUS"))
 452                 return handle_scsi_hyperv(parent, path, 38);
 453
 454         return handle_scsi_default(parent, path);
 455 }
 456
 457 static sd_device *handle_cciss(sd_device *parent, char **path) {
 458         const char *str;
 459         unsigned controller, disk;
 460
 461         if (sd_device_get_sysname(parent, &str) < 0)
 462                 return NULL;
 463         if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
 464                 return NULL;
 465
 466         path_prepend(path, "cciss-disk%u", disk);
 467         return skip_subsystem(parent, "cciss");
 468 }
 469
 470 static void handle_scsi_tape(sd_device *dev, char **path) {
 471         const char *name;
 472
 473         /* must be the last device in the syspath */
 474         if (*path)
 475                 return;
 476
 477         if (sd_device_get_sysname(dev, &name) < 0)
 478                 return;
 479
 480         if (startswith(name, "nst") && strchr("lma", name[3]))
 481                 path_prepend(path, "nst%c", name[3]);
 482         else if (startswith(name, "st") && strchr("lma", name[2]))
 483                 path_prepend(path, "st%c", name[2]);
 484 }
 485
 486 static int get_usb_revision(sd_device *dev) {
 487         uint8_t protocol;
 488         const char *s;
 489         int r;
 490
 491         assert(dev);
 492
 493         /* Returns usb revision 1, 2, or 3. */
 494
 495         r = sd_device_get_sysattr_value(dev, "bDeviceProtocol", &s);
 496         if (r < 0)
 497                 return r;
 498
 499         r = safe_atou8_full(s, 16, &protocol);
 500         if (r < 0)
 501                 return r;
 502
 503         switch (protocol) {
 504         case USB_HUB_PR_HS_NO_TT: /* Full speed hub (USB1) or Hi-speed hub without TT (USB2) */
 505
 506                 /* See speed_show() in drivers/usb/core/sysfs.c of the kernel. */
 507                 r = sd_device_get_sysattr_value(dev, "speed", &s);
 508                 if (r < 0)
 509                         return r;
 510
 511                 if (streq(s, "480"))
 512                         return 2;
 513
 514                 return 1;
 515
 516         case USB_HUB_PR_HS_SINGLE_TT: /* Hi-speed hub with single TT */
 517         case USB_HUB_PR_HS_MULTI_TT: /* Hi-speed hub with multiple TT */
 518                 return 2;
 519
 520         case USB_HUB_PR_SS: /* Super speed hub */
 521                 return 3;
 522
 523         default:
 524                 return -EPROTONOSUPPORT;
 525         }
 526 }
 527
 528 static sd_device *handle_usb(sd_device *parent, char **path) {
 529         const char *str, *port;
 530         int r;
 531
 532         if (!device_is_devtype(parent, "usb_interface") && !device_is_devtype(parent, "usb_device"))
 533                 return parent;
 534
 535         if (sd_device_get_sysname(parent, &str) < 0)
 536                 return parent;
 537         port = strchr(str, '-');
 538         if (!port)
 539                 return parent;
 540         port++;
 541
 542         parent = skip_subsystem(parent, "usb");
 543         if (!parent)
 544                 return NULL;
 545
 546         /* USB host number may change across reboots (and probably even without reboot). The part after USB
 547          * host number is determined by device topology and so does not change. Hence, drop the host number
 548          * and always use '0' instead.
 549          *
 550          * xHCI host controllers may register two (or more?) USB root hubs for USB 2.0 and USB 3.0, and the
 551          * sysname, whose host number replaced with 0, of a device under the hubs may conflict with others.
 552          * To avoid the conflict, let's include the USB revision of the root hub to the PATH_ID.
 553          * See issue https://github.com/systemd/systemd/issues/19406 for more details. */
 554         r = get_usb_revision(parent);
 555         if (r < 0) {
 556                 log_device_debug_errno(parent, r, "Failed to get the USB revision number, ignoring: %m");
 557                 path_prepend(path, "usb-0:%s", port);
 558         } else {
 559                 assert(r > 0);
 560                 path_prepend(path, "usbv%i-0:%s", r, port);
 561         }
 562
 563         return parent;
 564 }
 565
 566 static sd_device *handle_bcma(sd_device *parent, char **path) {
 567         const char *sysname;
 568         unsigned core;
 569
 570         if (sd_device_get_sysname(parent, &sysname) < 0)
 571                 return NULL;
 572         if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
 573                 return NULL;
 574
 575         path_prepend(path, "bcma-%u", core);
 576         return parent;
 577 }
 578
 579 /* Handle devices of AP bus in System z platform. */
 580 static sd_device *handle_ap(sd_device *parent, char **path) {
 581         const char *type, *func;
 582
 583         assert(parent);
 584         assert(path);
 585
 586         if (sd_device_get_sysattr_value(parent, "type", &type) >= 0 &&
 587             sd_device_get_sysattr_value(parent, "ap_functions", &func) >= 0)
 588                 path_prepend(path, "ap-%s-%s", type, func);
 589         else {
 590                 const char *sysname;
 591
 592                 if (sd_device_get_sysname(parent, &sysname) >= 0)
 593                         path_prepend(path, "ap-%s", sysname);
 594         }
 595
 596         return skip_subsystem(parent, "ap");
 597 }
 598
 599 static int find_real_nvme_parent(sd_device *dev, sd_device **ret) {
 600         _cleanup_(sd_device_unrefp) sd_device *nvme = NULL;
 601         const char *sysname, *end, *devpath;
 602         int r;
 603
 604         /* If the device belongs to "nvme-subsystem" (not to be confused with "nvme"), which happens when
 605          * NVMe multipathing is enabled in the kernel (/sys/module/nvme_core/parameters/multipath is Y),
 606          * then the syspath is something like the following:
 607          *   /sys/devices/virtual/nvme-subsystem/nvme-subsys0/nvme0n1
 608          * Hence, we need to find the 'real parent' in "nvme" subsystem, e.g,
 609          *   /sys/devices/pci0000:00/0000:00:1c.4/0000:3c:00.0/nvme/nvme0 */
 610
 611         assert(dev);
 612         assert(ret);
 613
 614         r = sd_device_get_sysname(dev, &sysname);
 615         if (r < 0)
 616                 return r;
 617
 618         /* The sysname format of nvme block device is nvme%d[c%d]n%d[p%d], e.g. nvme0n1p2 or nvme0c1n2.
 619          * (Note, nvme device with 'c' can be ignored, as they are hidden. )
 620          * The sysname format of nvme subsystem device is nvme%d.
 621          * See nvme_alloc_ns() and nvme_init_ctrl() in drivers/nvme/host/core.c for more details. */
 622         end = startswith(sysname, "nvme");
 623         if (!end)
 624                 return -ENXIO;
 625
 626         end += strspn(end, DIGITS);
 627         sysname = strndupa_safe(sysname, end - sysname);
 628
 629         r = sd_device_new_from_subsystem_sysname(&nvme, "nvme", sysname);
 630         if (r < 0)
 631                 return r;
 632
 633         r = sd_device_get_devpath(nvme, &devpath);
 634         if (r < 0)
 635                 return r;
 636
 637         /* If the 'real parent' is (still) virtual, e.g. for nvmf disks, refuse to set ID_PATH. */
 638         if (path_startswith(devpath, "/devices/virtual/"))
 639                 return -ENXIO;
 640
 641         *ret = TAKE_PTR(nvme);
 642         return 0;
 643 }
 644
 645 static void add_id_with_usb_revision(sd_device *dev, bool test, char *path) {
 646         char *p;
 647         int r;
 648
 649         assert(dev);
 650         assert(path);
 651
 652         /* When the path contains the USB revision, let's adds ID_PATH_WITH_USB_REVISION property and
 653          * drop the version specifier for later use. */
 654
 655         p = strstrafter(path, "-usbv");
 656         if (!p)
 657                 return;
 658         if (!ascii_isdigit(p[0]))
 659                 return;
 660         if (p[1] != '-')
 661                 return;
 662
 663         r = udev_builtin_add_property(dev, test, "ID_PATH_WITH_USB_REVISION", path);
 664         if (r < 0)
 665                 log_device_debug_errno(dev, r, "Failed to add ID_PATH_WITH_USB_REVISION property, ignoring: %m");
 666
 667         /* Drop the USB revision specifier for backward compatibility. */
 668         memmove(p - 1, p + 1, strlen(p + 1) + 1);
 669 }
 670
 671 static void add_id_tag(sd_device *dev, bool test, const char *path) {
 672         char tag[UDEV_NAME_SIZE];
 673         size_t i = 0;
 674         int r;
 675
 676         /* compose valid udev tag name */
 677         for (const char *p = path; *p; p++) {
 678                 if (ascii_isdigit(*p) ||
 679                     ascii_isalpha(*p) ||
 680                     *p == '-') {
 681                         tag[i++] = *p;
 682                         continue;
 683                 }
 684
 685                 /* skip all leading '_' */
 686                 if (i == 0)
 687                         continue;
 688
 689                 /* avoid second '_' */
 690                 if (tag[i-1] == '_')
 691                         continue;
 692
 693                 tag[i++] = '_';
 694         }
 695         /* strip trailing '_' */
 696         while (i > 0 && tag[i-1] == '_')
 697                 i--;
 698         tag[i] = '\0';
 699
 700         r = udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 701         if (r < 0)
 702                 log_device_debug_errno(dev, r, "Failed to add ID_PATH_TAG property, ignoring: %m");
 703 }
 704
 705 static int builtin_path_id(UdevEvent *event, int argc, char *argv[], bool test) {
 706         sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
 707         _cleanup_(sd_device_unrefp) sd_device *dev_other_branch = NULL;
 708         _cleanup_free_ char *path = NULL, *compat_path = NULL;
 709         bool supported_transport = false, supported_parent = false;
 710         int r;
 711
 712         /* walk up the chain of devices and compose path */
 713         for (sd_device *parent = dev; parent; ) {
 714                 const char *sysname;
 715
 716                 if (sd_device_get_sysname(parent, &sysname) < 0) {
 717                         ;
 718                 } else if (device_in_subsystem(parent, "scsi_tape")) {
 719                         handle_scsi_tape(parent, &path);
 720                 } else if (device_in_subsystem(parent, "scsi")) {
 721                         parent = handle_scsi(parent, &path, &compat_path, &supported_parent);
 722                         supported_transport = true;
 723                 } else if (device_in_subsystem(parent, "cciss")) {
 724                         parent = handle_cciss(parent, &path);
 725                         supported_transport = true;
 726                 } else if (device_in_subsystem(parent, "usb")) {
 727                         parent = handle_usb(parent, &path);
 728                         supported_transport = true;
 729                 } else if (device_in_subsystem(parent, "bcma")) {
 730                         parent = handle_bcma(parent, &path);
 731                         supported_transport = true;
 732                 } else if (device_in_subsystem(parent, "serio")) {
 733                         const char *sysnum;
 734
 735                         if (sd_device_get_sysnum(parent, &sysnum) >= 0 && sysnum) {
 736                                 path_prepend(&path, "serio-%s", sysnum);
 737                                 parent = skip_subsystem(parent, "serio");
 738                         }
 739                 } else if (device_in_subsystem(parent, "pci")) {
 740                         path_prepend(&path, "pci-%s", sysname);
 741                         if (compat_path)
 742                                 path_prepend(&compat_path, "pci-%s", sysname);
 743                         parent = skip_subsystem(parent, "pci");
 744                         supported_parent = true;
 745                 } else if (device_in_subsystem(parent, "platform")) {
 746                         path_prepend(&path, "platform-%s", sysname);
 747                         if (compat_path)
 748                                 path_prepend(&compat_path, "platform-%s", sysname);
 749                         parent = skip_subsystem(parent, "platform");
 750                         supported_transport = true;
 751                         supported_parent = true;
 752                 } else if (device_in_subsystem(parent, "amba")) {
 753                         path_prepend(&path, "amba-%s", sysname);
 754                         if (compat_path)
 755                                 path_prepend(&compat_path, "amba-%s", sysname);
 756                         parent = skip_subsystem(parent, "amba");
 757                         supported_transport = true;
 758                         supported_parent = true;
 759                 } else if (device_in_subsystem(parent, "acpi")) {
 760                         path_prepend(&path, "acpi-%s", sysname);
 761                         if (compat_path)
 762                                 path_prepend(&compat_path, "acpi-%s", sysname);
 763                         parent = skip_subsystem(parent, "acpi");
 764                         supported_parent = true;
 765                 } else if (device_in_subsystem(parent, "xen")) {
 766                         path_prepend(&path, "xen-%s", sysname);
 767                         if (compat_path)
 768                                 path_prepend(&compat_path, "xen-%s", sysname);
 769                         parent = skip_subsystem(parent, "xen");
 770                         supported_parent = true;
 771                 } else if (device_in_subsystem(parent, "virtio")) {
 772                         parent = skip_subsystem(parent, "virtio");
 773                         supported_transport = true;
 774                 } else if (device_in_subsystem(parent, "scm")) {
 775                         path_prepend(&path, "scm-%s", sysname);
 776                         if (compat_path)
 777                                 path_prepend(&compat_path, "scm-%s", sysname);
 778                         parent = skip_subsystem(parent, "scm");
 779                         supported_transport = true;
 780                         supported_parent = true;
 781                 } else if (device_in_subsystem(parent, "ccw")) {
 782                         path_prepend(&path, "ccw-%s", sysname);
 783                         if (compat_path)
 784                                 path_prepend(&compat_path, "ccw-%s", sysname);
 785                         parent = skip_subsystem(parent, "ccw");
 786                         supported_transport = true;
 787                         supported_parent = true;
 788                 } else if (device_in_subsystem(parent, "ccwgroup")) {
 789                         path_prepend(&path, "ccwgroup-%s", sysname);
 790                         if (compat_path)
 791                                 path_prepend(&compat_path, "ccwgroup-%s", sysname);
 792                         parent = skip_subsystem(parent, "ccwgroup");
 793                         supported_transport = true;
 794                         supported_parent = true;
 795                 } else if (device_in_subsystem(parent, "ap")) {
 796                         parent = handle_ap(parent, &path);
 797                         supported_transport = true;
 798                         supported_parent = true;
 799                 } else if (device_in_subsystem(parent, "iucv")) {
 800                         path_prepend(&path, "iucv-%s", sysname);
 801                         if (compat_path)
 802                                 path_prepend(&compat_path, "iucv-%s", sysname);
 803                         parent = skip_subsystem(parent, "iucv");
 804                         supported_transport = true;
 805                         supported_parent = true;
 806                 } else if (device_in_subsystem(parent, "nvme") || device_in_subsystem(parent, "nvme-subsystem")) {
 807                         const char *nsid;
 808
 809                         if (sd_device_get_sysattr_value(dev, "nsid", &nsid) >= 0) {
 810                                 path_prepend(&path, "nvme-%s", nsid);
 811                                 if (compat_path)
 812                                         path_prepend(&compat_path, "nvme-%s", nsid);
 813
 814                                 if (device_in_subsystem(parent, "nvme-subsystem")) {
 815                                         r = find_real_nvme_parent(dev, &dev_other_branch);
 816                                         if (r < 0)
 817                                                 return r;
 818
 819                                         parent = dev_other_branch;
 820                                 }
 821
 822                                 parent = skip_subsystem(parent, "nvme");
 823                                 supported_parent = true;
 824                                 supported_transport = true;
 825                         }
 826                 } else if (device_in_subsystem(parent, "spi")) {
 827                         const char *sysnum;
 828
 829                         if (sd_device_get_sysnum(parent, &sysnum) >= 0 && sysnum) {
 830                                 path_prepend(&path, "cs-%s", sysnum);
 831                                 parent = skip_subsystem(parent, "spi");
 832                         }
 833                 }
 834
 835                 if (!parent)
 836                         break;
 837                 if (sd_device_get_parent(parent, &parent) < 0)
 838                         break;
 839         }
 840
 841         if (!path)
 842                 return -ENOENT;
 843
 844         /*
 845          * Do not return devices with an unknown parent device type. They
 846          * might produce conflicting IDs if the parent does not provide a
 847          * unique and predictable name.
 848          */
 849         if (!supported_parent)
 850                 return -ENOENT;
 851
 852         /*
 853          * Do not return block devices without a well-known transport. Some
 854          * devices do not expose their buses and do not provide a unique
 855          * and predictable name that way.
 856          */
 857         if (device_in_subsystem(dev, "block") && !supported_transport)
 858                 return -ENOENT;
 859
 860         add_id_with_usb_revision(dev, test, path);
 861
 862         r = udev_builtin_add_property(dev, test, "ID_PATH", path);
 863         if (r < 0)
 864                 log_device_debug_errno(dev, r, "Failed to add ID_PATH property, ignoring: %m");
 865
 866         add_id_tag(dev, test, path);
 867
 868         /*
 869          * Compatible link generation for ATA devices
 870          * we assign compat_link to the env variable
 871          * ID_PATH_ATA_COMPAT
 872          */
 873         if (compat_path)
 874                 udev_builtin_add_property(dev, test, "ID_PATH_ATA_COMPAT", compat_path);
 875
 876         return 0;
 877 }
 878
 879 const UdevBuiltin udev_builtin_path_id = {
 880         .name = "path_id",
 881         .cmd = builtin_path_id,
 882         .help = "Compose persistent device path",
 883         .run_once = true,
 884 };