2 * compose persistent device path
4 * Copyright (C) 2009-2011 Kay Sievers <kay@vrfy.org>
6 * Logic based on Hannes Reinecke's shell script.
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.
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.
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/>.
36 static int path_prepend(char **path, const char *fmt, ...) {
42 err = vasprintf(&pre, fmt, va);
50 err = asprintf(&new, "%s-%s", pre, *path);
64 ** Linux only supports 32 bit luns.
65 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
67 static int format_lun_number(struct udev_device *dev, char **path) {
68 unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
70 /* address method 0, peripheral device addressing with bus id of zero */
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);
77 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys) {
78 struct udev_device *parent = dev;
80 while (parent != NULL) {
81 const char *subsystem;
83 subsystem = udev_device_get_subsystem(parent);
84 if (subsystem == NULL || !streq(subsystem, subsys))
87 parent = udev_device_get_parent(parent);
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;
99 targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
100 if (targetdev == NULL)
103 fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
106 port = udev_device_get_sysattr_value(fcdev, "port_name");
112 format_lun_number(parent, &lun);
113 path_prepend(path, "fc-%s-%s", port, lun);
117 udev_device_unref(fcdev);
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;
129 targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
130 if (targetdev == NULL)
133 target_parent = udev_device_get_parent(targetdev);
134 if (target_parent == NULL)
137 sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
138 udev_device_get_sysname(target_parent));
142 sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
143 if (sas_address == NULL) {
148 format_lun_number(parent, &lun);
149 path_prepend(path, "sas-%s-%s", sas_address, lun);
153 udev_device_unref(sasdev);
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;
163 struct udev_device *conndev = NULL;
168 /* find iscsi session */
169 transportdev = parent;
171 transportdev = udev_device_get_parent(transportdev);
172 if (transportdev == NULL)
174 if (startswith(udev_device_get_sysname(transportdev), "session"))
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)
182 target = udev_device_get_sysattr_value(sessiondev, "targetname");
183 if (target == NULL) {
188 if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
192 conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
194 if (conndev == NULL) {
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) {
205 format_lun_number(parent, &lun);
206 path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
210 udev_device_unref(sessiondev);
211 udev_device_unref(conndev);
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;
225 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
229 name = udev_device_get_sysname(parent);
230 if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
234 * Rebase host offset to get the local relative number
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
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.
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.
251 base = strdup(udev_device_get_syspath(hostdev));
254 pos = strrchr(base, '/');
265 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
269 if (dent->d_name[0] == '.')
271 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
273 if (!startswith(dent->d_name, "host"))
275 i = strtoul(&dent->d_name[4], &rest, 10);
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
283 if (basenum == -1 || i < basenum)
293 path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
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;
307 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
311 vmbusdev = udev_device_get_parent(hostdev);
315 guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
319 if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
322 for (i = 1, k = 0; i < 36; i++) {
323 if (guid_str[i] == '-')
325 guid[k++] = guid_str[i];
329 format_lun_number(parent, &lun);
330 path_prepend(path, "vmbus-%s-%s", guid, lun);
335 static struct udev_device *handle_scsi(struct udev_device *parent, char **path) {
340 devtype = udev_device_get_devtype(parent);
341 if (devtype == NULL || !streq(devtype, "scsi_device"))
345 id = udev_device_get_sysattr_value(parent, "ieee1394_id");
347 parent = skip_subsystem(parent, "scsi");
348 path_prepend(path, "ieee1394-0x%s", id);
352 /* scsi sysfs does not have a "subsystem" for the transport */
353 name = udev_device_get_syspath(parent);
355 if (strstr(name, "/rport-") != NULL) {
356 parent = handle_scsi_fibre_channel(parent, path);
360 if (strstr(name, "/end_device-") != NULL) {
361 parent = handle_scsi_sas(parent, path);
365 if (strstr(name, "/session") != NULL) {
366 parent = handle_scsi_iscsi(parent, path);
371 * We do not support the ATA transport class, it uses global counters
372 * to name the ata devices which numbers spread across multiple
375 * The real link numbers are not exported. Also, possible chains of ports
376 * behind port multipliers cannot be composed that way.
378 * Until all that is solved at the kernel level, there are no by-path/
379 * links for ATA devices.
381 if (strstr(name, "/ata") != NULL) {
386 if (strstr(name, "/vmbus_") != NULL) {
387 parent = handle_scsi_hyperv(parent, path);
391 parent = handle_scsi_default(parent, path);
396 static struct udev_device *handle_cciss(struct udev_device *parent, char **path) {
398 unsigned int controller, disk;
400 str = udev_device_get_sysname(parent);
401 if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
404 path_prepend(path, "cciss-disk%u", disk);
405 parent = skip_subsystem(parent, "cciss");
409 static void handle_scsi_tape(struct udev_device *dev, char **path) {
412 /* must be the last device in the syspath */
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]);
423 static struct udev_device *handle_usb(struct udev_device *parent, char **path) {
428 devtype = udev_device_get_devtype(parent);
431 if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
434 str = udev_device_get_sysname(parent);
435 port = strchr(str, '-');
440 parent = skip_subsystem(parent, "usb");
441 path_prepend(path, "usb-0:%s", port);
445 static struct udev_device *handle_bcma(struct udev_device *parent, char **path) {
449 sysname = udev_device_get_sysname(parent);
450 if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
453 path_prepend(path, "bcma-%u", core);
457 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path) {
458 struct udev_device *scsi_dev;
460 scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
461 if (scsi_dev != NULL) {
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);
475 path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
477 parent = skip_subsystem(parent, "ccw");
481 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test) {
482 struct udev_device *parent;
484 bool supported_transport = false;
485 bool supported_parent = false;
488 parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
489 if (parent != NULL) {
490 handle_ccw(parent, dev, &path);
494 /* walk up the chain of devices and compose path */
496 while (parent != NULL) {
499 subsys = udev_device_get_subsystem(parent);
500 if (subsys == NULL) {
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;
543 parent = udev_device_get_parent(parent);
547 * Do return devices with have an unknown type of parent device, they
548 * might produce conflicting IDs below multiple independent parent
551 if (!supported_parent) {
557 * Do not return a have-only a single-parent block devices, some
558 * have entire hidden buses behind it, and not create predictable
561 if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
568 char tag[UTIL_NAME_SIZE];
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') ||
582 /* skip all leading '_' */
586 /* avoid second '_' */
592 /* strip trailing '_' */
593 while (i > 0 && tag[i-1] == '_')
597 udev_builtin_add_property(dev, test, "ID_PATH", path);
598 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
605 const struct udev_builtin udev_builtin_path_id = {
607 .cmd = builtin_path_id,
608 .help = "compose persistent device path",