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_wide_port(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_sas(struct udev_device *parent, char **path)
159 struct udev *udev = udev_device_get_udev(parent);
160 struct udev_device *targetdev;
161 struct udev_device *target_parent;
162 struct udev_device *port;
163 struct udev_device *expander;
164 struct udev_device *target_sasdev = NULL;
165 struct udev_device *expander_sasdev = NULL;
166 struct udev_device *port_sasdev = NULL;
167 const char *sas_address = NULL;
169 const char *phy_count;
172 targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
173 if (targetdev == NULL)
176 target_parent = udev_device_get_parent(targetdev);
177 if (target_parent == NULL)
181 target_sasdev = udev_device_new_from_subsystem_sysname(udev,
182 "sas_device", udev_device_get_sysname(target_parent));
183 if (target_sasdev == NULL)
186 /* The next parent is sas port */
187 port = udev_device_get_parent(target_parent);
193 /* Get port device */
194 port_sasdev = udev_device_new_from_subsystem_sysname(udev,
195 "sas_port", udev_device_get_sysname(port));
197 phy_count = udev_device_get_sysattr_value(port_sasdev, "num_phys");
198 if (phy_count == NULL) {
203 /* Check if we are simple disk */
204 if (strncmp(phy_count, "1", 2) != 0) {
205 parent = handle_scsi_sas_wide_port(parent, path);
209 /* Get connected phy */
210 phy_id = udev_device_get_sysattr_value(target_sasdev, "phy_identifier");
211 if (phy_id == NULL) {
216 /* The port's parent is either hba or expander */
217 expander = udev_device_get_parent(port);
218 if (expander == NULL) {
223 /* Get expander device */
224 expander_sasdev = udev_device_new_from_subsystem_sysname(udev,
225 "sas_device", udev_device_get_sysname(expander));
226 if (expander_sasdev != NULL) {
227 /* Get expander's address */
228 sas_address = udev_device_get_sysattr_value(expander_sasdev,
230 if (sas_address == NULL) {
236 format_lun_number(parent, &lun);
238 path_prepend(path, "sas-exp%s-phy%s-%s", sas_address, phy_id, lun);
240 path_prepend(path, "sas-phy%s-%s", phy_id, lun);
245 udev_device_unref(target_sasdev);
246 udev_device_unref(expander_sasdev);
247 udev_device_unref(port_sasdev);
251 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path) {
252 struct udev *udev = udev_device_get_udev(parent);
253 struct udev_device *transportdev;
254 struct udev_device *sessiondev = NULL;
257 struct udev_device *conndev = NULL;
262 /* find iscsi session */
263 transportdev = parent;
265 transportdev = udev_device_get_parent(transportdev);
266 if (transportdev == NULL)
268 if (startswith(udev_device_get_sysname(transportdev), "session"))
272 /* find iscsi session device */
273 sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
274 if (sessiondev == NULL)
276 target = udev_device_get_sysattr_value(sessiondev, "targetname");
277 if (target == NULL) {
282 if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
286 conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
288 if (conndev == NULL) {
292 addr = udev_device_get_sysattr_value(conndev, "persistent_address");
293 port = udev_device_get_sysattr_value(conndev, "persistent_port");
294 if (addr == NULL || port == NULL) {
299 format_lun_number(parent, &lun);
300 path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
304 udev_device_unref(sessiondev);
305 udev_device_unref(conndev);
309 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path) {
310 struct udev_device *hostdev;
311 int host, bus, target, lun;
319 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
323 name = udev_device_get_sysname(parent);
324 if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
328 * Rebase host offset to get the local relative number
330 * Note: This is by definition racy, unreliable and too simple.
331 * Please do not copy this model anywhere. It's just a left-over
332 * from the time we had no idea how things should look like in
335 * Making assumptions about a global in-kernel counter and use
336 * that to calculate a local offset is a very broken concept. It
337 * can only work as long as things are in strict order.
339 * The kernel needs to export the instance/port number of a
340 * controller directly, without the need for rebase magic like
341 * this. Manual driver unbind/bind, parallel hotplug/unplug will
342 * get into the way of this "I hope it works" logic.
345 base = strdup(udev_device_get_syspath(hostdev));
348 pos = strrchr(base, '/');
359 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
363 if (dent->d_name[0] == '.')
365 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
367 if (!startswith(dent->d_name, "host"))
369 i = strtoul(&dent->d_name[4], &rest, 10);
373 * find the smallest number; the host really needs to export its
374 * own instance number per parent device; relying on the global host
375 * enumeration and plainly rebasing the numbers sounds unreliable
377 if (basenum == -1 || i < basenum)
387 path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
393 static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char **path) {
394 struct udev_device *hostdev;
395 struct udev_device *vmbusdev;
396 const char *guid_str;
401 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
405 vmbusdev = udev_device_get_parent(hostdev);
409 guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
413 if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
416 for (i = 1, k = 0; i < 36; i++) {
417 if (guid_str[i] == '-')
419 guid[k++] = guid_str[i];
423 format_lun_number(parent, &lun);
424 path_prepend(path, "vmbus-%s-%s", guid, lun);
429 static struct udev_device *handle_scsi(struct udev_device *parent, char **path, bool *supported_parent) {
434 devtype = udev_device_get_devtype(parent);
435 if (devtype == NULL || !streq(devtype, "scsi_device"))
439 id = udev_device_get_sysattr_value(parent, "ieee1394_id");
441 parent = skip_subsystem(parent, "scsi");
442 path_prepend(path, "ieee1394-0x%s", id);
443 *supported_parent = true;
447 /* scsi sysfs does not have a "subsystem" for the transport */
448 name = udev_device_get_syspath(parent);
450 if (strstr(name, "/rport-") != NULL) {
451 parent = handle_scsi_fibre_channel(parent, path);
452 *supported_parent = true;
456 if (strstr(name, "/end_device-") != NULL) {
457 parent = handle_scsi_sas(parent, path);
458 *supported_parent = true;
462 if (strstr(name, "/session") != NULL) {
463 parent = handle_scsi_iscsi(parent, path);
464 *supported_parent = true;
469 * We do not support the ATA transport class, it uses global counters
470 * to name the ata devices which numbers spread across multiple
473 * The real link numbers are not exported. Also, possible chains of ports
474 * behind port multipliers cannot be composed that way.
476 * Until all that is solved at the kernel level, there are no by-path/
477 * links for ATA devices.
479 if (strstr(name, "/ata") != NULL) {
484 if (strstr(name, "/vmbus_") != NULL) {
485 parent = handle_scsi_hyperv(parent, path);
489 parent = handle_scsi_default(parent, path);
494 static struct udev_device *handle_cciss(struct udev_device *parent, char **path) {
496 unsigned int controller, disk;
498 str = udev_device_get_sysname(parent);
499 if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
502 path_prepend(path, "cciss-disk%u", disk);
503 parent = skip_subsystem(parent, "cciss");
507 static void handle_scsi_tape(struct udev_device *dev, char **path) {
510 /* must be the last device in the syspath */
514 name = udev_device_get_sysname(dev);
515 if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
516 path_prepend(path, "nst%c", name[3]);
517 else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
518 path_prepend(path, "st%c", name[2]);
521 static struct udev_device *handle_usb(struct udev_device *parent, char **path) {
526 devtype = udev_device_get_devtype(parent);
529 if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
532 str = udev_device_get_sysname(parent);
533 port = strchr(str, '-');
538 parent = skip_subsystem(parent, "usb");
539 path_prepend(path, "usb-0:%s", port);
543 static struct udev_device *handle_bcma(struct udev_device *parent, char **path) {
547 sysname = udev_device_get_sysname(parent);
548 if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
551 path_prepend(path, "bcma-%u", core);
555 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path) {
556 struct udev_device *scsi_dev;
558 scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
559 if (scsi_dev != NULL) {
564 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
565 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
566 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
567 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
568 path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
573 path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
575 parent = skip_subsystem(parent, "ccw");
579 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test) {
580 struct udev_device *parent;
582 bool supported_transport = false;
583 bool supported_parent = false;
586 parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
587 if (parent != NULL) {
588 handle_ccw(parent, dev, &path);
592 /* walk up the chain of devices and compose path */
594 while (parent != NULL) {
597 subsys = udev_device_get_subsystem(parent);
598 if (subsys == NULL) {
600 } else if (streq(subsys, "scsi_tape")) {
601 handle_scsi_tape(parent, &path);
602 } else if (streq(subsys, "scsi")) {
603 parent = handle_scsi(parent, &path, &supported_parent);
604 supported_transport = true;
605 } else if (streq(subsys, "cciss")) {
606 parent = handle_cciss(parent, &path);
607 supported_transport = true;
608 } else if (streq(subsys, "usb")) {
609 parent = handle_usb(parent, &path);
610 supported_transport = true;
611 } else if (streq(subsys, "bcma")) {
612 parent = handle_bcma(parent, &path);
613 supported_transport = true;
614 } else if (streq(subsys, "serio")) {
615 path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
616 parent = skip_subsystem(parent, "serio");
617 } else if (streq(subsys, "pci")) {
618 path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
619 parent = skip_subsystem(parent, "pci");
620 supported_parent = true;
621 } else if (streq(subsys, "platform")) {
622 path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
623 parent = skip_subsystem(parent, "platform");
624 supported_transport = true;
625 supported_parent = true;
626 } else if (streq(subsys, "acpi")) {
627 path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
628 parent = skip_subsystem(parent, "acpi");
629 supported_parent = true;
630 } else if (streq(subsys, "xen")) {
631 path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
632 parent = skip_subsystem(parent, "xen");
633 supported_parent = true;
634 } else if (streq(subsys, "scm")) {
635 path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
636 parent = skip_subsystem(parent, "scm");
637 supported_transport = true;
638 supported_parent = true;
641 parent = udev_device_get_parent(parent);
645 * Do not return devices with an unknown parent device type. They
646 * might produce conflicting IDs if the parent does not provide a
647 * unique and predictable name.
649 if (!supported_parent) {
655 * Do not return block devices without a well-known transport. Some
656 * devices do not expose their buses and do not provide a unique
657 * and predictable name that way.
659 if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
666 char tag[UTIL_NAME_SIZE];
670 /* compose valid udev tag name */
671 for (p = path, i = 0; *p; p++) {
672 if ((*p >= '0' && *p <= '9') ||
673 (*p >= 'A' && *p <= 'Z') ||
674 (*p >= 'a' && *p <= 'z') ||
680 /* skip all leading '_' */
684 /* avoid second '_' */
690 /* strip trailing '_' */
691 while (i > 0 && tag[i-1] == '_')
695 udev_builtin_add_property(dev, test, "ID_PATH", path);
696 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
703 const struct udev_builtin udev_builtin_path_id = {
705 .cmd = builtin_path_id,
706 .help = "Compose persistent device path",