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
;
83 while (parent
!= NULL
) {
84 const char *subsystem
;
86 subsystem
= udev_device_get_subsystem(parent
);
87 if (subsystem
== NULL
|| !streq(subsystem
, subsys
))
90 parent
= udev_device_get_parent(parent
);
95 static struct udev_device
*handle_scsi_fibre_channel(struct udev_device
*parent
, char **path
) {
96 struct udev
*udev
= udev_device_get_udev(parent
);
97 struct udev_device
*targetdev
;
98 struct udev_device
*fcdev
= NULL
;
105 targetdev
= udev_device_get_parent_with_subsystem_devtype(parent
, "scsi", "scsi_target");
106 if (targetdev
== NULL
)
109 fcdev
= udev_device_new_from_subsystem_sysname(udev
, "fc_transport", udev_device_get_sysname(targetdev
));
112 port
= udev_device_get_sysattr_value(fcdev
, "port_name");
118 format_lun_number(parent
, &lun
);
119 path_prepend(path
, "fc-%s-%s", port
, lun
);
123 udev_device_unref(fcdev
);
127 static struct udev_device
*handle_scsi_sas_wide_port(struct udev_device
*parent
, char **path
) {
128 struct udev
*udev
= udev_device_get_udev(parent
);
129 struct udev_device
*targetdev
;
130 struct udev_device
*target_parent
;
131 struct udev_device
*sasdev
;
132 const char *sas_address
;
138 targetdev
= udev_device_get_parent_with_subsystem_devtype(parent
, "scsi", "scsi_target");
139 if (targetdev
== NULL
)
142 target_parent
= udev_device_get_parent(targetdev
);
143 if (target_parent
== NULL
)
146 sasdev
= udev_device_new_from_subsystem_sysname(udev
, "sas_device",
147 udev_device_get_sysname(target_parent
));
151 sas_address
= udev_device_get_sysattr_value(sasdev
, "sas_address");
152 if (sas_address
== NULL
) {
157 format_lun_number(parent
, &lun
);
158 path_prepend(path
, "sas-%s-%s", sas_address
, lun
);
162 udev_device_unref(sasdev
);
166 static struct udev_device
*handle_scsi_sas(struct udev_device
*parent
, char **path
)
168 struct udev
*udev
= udev_device_get_udev(parent
);
169 struct udev_device
*targetdev
;
170 struct udev_device
*target_parent
;
171 struct udev_device
*port
;
172 struct udev_device
*expander
;
173 struct udev_device
*target_sasdev
= NULL
;
174 struct udev_device
*expander_sasdev
= NULL
;
175 struct udev_device
*port_sasdev
= NULL
;
176 const char *sas_address
= NULL
;
178 const char *phy_count
;
184 targetdev
= udev_device_get_parent_with_subsystem_devtype(parent
, "scsi", "scsi_target");
185 if (targetdev
== NULL
)
188 target_parent
= udev_device_get_parent(targetdev
);
189 if (target_parent
== NULL
)
193 target_sasdev
= udev_device_new_from_subsystem_sysname(udev
,
194 "sas_device", udev_device_get_sysname(target_parent
));
195 if (target_sasdev
== NULL
)
198 /* The next parent is sas port */
199 port
= udev_device_get_parent(target_parent
);
205 /* Get port device */
206 port_sasdev
= udev_device_new_from_subsystem_sysname(udev
,
207 "sas_port", udev_device_get_sysname(port
));
209 phy_count
= udev_device_get_sysattr_value(port_sasdev
, "num_phys");
210 if (phy_count
== NULL
) {
215 /* Check if we are simple disk */
216 if (strncmp(phy_count
, "1", 2) != 0) {
217 parent
= handle_scsi_sas_wide_port(parent
, path
);
221 /* Get connected phy */
222 phy_id
= udev_device_get_sysattr_value(target_sasdev
, "phy_identifier");
223 if (phy_id
== NULL
) {
228 /* The port's parent is either hba or expander */
229 expander
= udev_device_get_parent(port
);
230 if (expander
== NULL
) {
235 /* Get expander device */
236 expander_sasdev
= udev_device_new_from_subsystem_sysname(udev
,
237 "sas_device", udev_device_get_sysname(expander
));
238 if (expander_sasdev
!= NULL
) {
239 /* Get expander's address */
240 sas_address
= udev_device_get_sysattr_value(expander_sasdev
,
242 if (sas_address
== NULL
) {
248 format_lun_number(parent
, &lun
);
250 path_prepend(path
, "sas-exp%s-phy%s-%s", sas_address
, phy_id
, lun
);
252 path_prepend(path
, "sas-phy%s-%s", phy_id
, lun
);
257 udev_device_unref(target_sasdev
);
258 udev_device_unref(expander_sasdev
);
259 udev_device_unref(port_sasdev
);
263 static struct udev_device
*handle_scsi_iscsi(struct udev_device
*parent
, char **path
) {
264 struct udev
*udev
= udev_device_get_udev(parent
);
265 struct udev_device
*transportdev
;
266 struct udev_device
*sessiondev
= NULL
;
269 struct udev_device
*conndev
= NULL
;
277 /* find iscsi session */
278 transportdev
= parent
;
280 transportdev
= udev_device_get_parent(transportdev
);
281 if (transportdev
== NULL
)
283 if (startswith(udev_device_get_sysname(transportdev
), "session"))
287 /* find iscsi session device */
288 sessiondev
= udev_device_new_from_subsystem_sysname(udev
, "iscsi_session", udev_device_get_sysname(transportdev
));
289 if (sessiondev
== NULL
)
291 target
= udev_device_get_sysattr_value(sessiondev
, "targetname");
292 if (target
== NULL
) {
297 if (asprintf(&connname
, "connection%s:0", udev_device_get_sysnum(transportdev
)) < 0) {
301 conndev
= udev_device_new_from_subsystem_sysname(udev
, "iscsi_connection", connname
);
303 if (conndev
== NULL
) {
307 addr
= udev_device_get_sysattr_value(conndev
, "persistent_address");
308 port
= udev_device_get_sysattr_value(conndev
, "persistent_port");
309 if (addr
== NULL
|| port
== NULL
) {
314 format_lun_number(parent
, &lun
);
315 path_prepend(path
, "ip-%s:%s-iscsi-%s-%s", addr
, port
, target
, lun
);
319 udev_device_unref(sessiondev
);
320 udev_device_unref(conndev
);
324 static struct udev_device
*handle_scsi_default(struct udev_device
*parent
, char **path
) {
325 struct udev_device
*hostdev
;
326 int host
, bus
, target
, lun
;
337 hostdev
= udev_device_get_parent_with_subsystem_devtype(parent
, "scsi", "scsi_host");
341 name
= udev_device_get_sysname(parent
);
342 if (sscanf(name
, "%d:%d:%d:%d", &host
, &bus
, &target
, &lun
) != 4)
346 * Rebase host offset to get the local relative number
348 * Note: This is by definition racy, unreliable and too simple.
349 * Please do not copy this model anywhere. It's just a left-over
350 * from the time we had no idea how things should look like in
353 * Making assumptions about a global in-kernel counter and use
354 * that to calculate a local offset is a very broken concept. It
355 * can only work as long as things are in strict order.
357 * The kernel needs to export the instance/port number of a
358 * controller directly, without the need for rebase magic like
359 * this. Manual driver unbind/bind, parallel hotplug/unplug will
360 * get into the way of this "I hope it works" logic.
363 base
= strdup(udev_device_get_syspath(hostdev
));
366 pos
= strrchr(base
, '/');
377 for (dent
= readdir(dir
); dent
!= NULL
; dent
= readdir(dir
)) {
381 if (dent
->d_name
[0] == '.')
383 if (dent
->d_type
!= DT_DIR
&& dent
->d_type
!= DT_LNK
)
385 if (!startswith(dent
->d_name
, "host"))
387 i
= strtoul(&dent
->d_name
[4], &rest
, 10);
391 * find the smallest number; the host really needs to export its
392 * own instance number per parent device; relying on the global host
393 * enumeration and plainly rebasing the numbers sounds unreliable
395 if (basenum
== -1 || i
< basenum
)
405 path_prepend(path
, "scsi-%u:%u:%u:%u", host
, bus
, target
, lun
);
411 static struct udev_device
*handle_scsi_hyperv(struct udev_device
*parent
, char **path
) {
412 struct udev_device
*hostdev
;
413 struct udev_device
*vmbusdev
;
414 const char *guid_str
;
422 hostdev
= udev_device_get_parent_with_subsystem_devtype(parent
, "scsi", "scsi_host");
426 vmbusdev
= udev_device_get_parent(hostdev
);
430 guid_str
= udev_device_get_sysattr_value(vmbusdev
, "device_id");
434 if (strlen(guid_str
) < 37 || guid_str
[0] != '{' || guid_str
[36] != '}')
437 for (i
= 1, k
= 0; i
< 36; i
++) {
438 if (guid_str
[i
] == '-')
440 guid
[k
++] = guid_str
[i
];
444 format_lun_number(parent
, &lun
);
445 path_prepend(path
, "vmbus-%s-%s", guid
, lun
);
450 static struct udev_device
*handle_scsi(struct udev_device
*parent
, char **path
, bool *supported_parent
) {
455 devtype
= udev_device_get_devtype(parent
);
456 if (devtype
== NULL
|| !streq(devtype
, "scsi_device"))
460 id
= udev_device_get_sysattr_value(parent
, "ieee1394_id");
462 parent
= skip_subsystem(parent
, "scsi");
463 path_prepend(path
, "ieee1394-0x%s", id
);
464 *supported_parent
= true;
468 /* scsi sysfs does not have a "subsystem" for the transport */
469 name
= udev_device_get_syspath(parent
);
471 if (strstr(name
, "/rport-") != NULL
) {
472 parent
= handle_scsi_fibre_channel(parent
, path
);
473 *supported_parent
= true;
477 if (strstr(name
, "/end_device-") != NULL
) {
478 parent
= handle_scsi_sas(parent
, path
);
479 *supported_parent
= true;
483 if (strstr(name
, "/session") != NULL
) {
484 parent
= handle_scsi_iscsi(parent
, path
);
485 *supported_parent
= true;
490 * We do not support the ATA transport class, it uses global counters
491 * to name the ata devices which numbers spread across multiple
494 * The real link numbers are not exported. Also, possible chains of ports
495 * behind port multipliers cannot be composed that way.
497 * Until all that is solved at the kernel level, there are no by-path/
498 * links for ATA devices.
500 if (strstr(name
, "/ata") != NULL
) {
505 if (strstr(name
, "/vmbus_") != NULL
) {
506 parent
= handle_scsi_hyperv(parent
, path
);
510 parent
= handle_scsi_default(parent
, path
);
515 static struct udev_device
*handle_cciss(struct udev_device
*parent
, char **path
) {
517 unsigned int controller
, disk
;
519 str
= udev_device_get_sysname(parent
);
520 if (sscanf(str
, "c%ud%u%*s", &controller
, &disk
) != 2)
523 path_prepend(path
, "cciss-disk%u", disk
);
524 parent
= skip_subsystem(parent
, "cciss");
528 static void handle_scsi_tape(struct udev_device
*dev
, char **path
) {
531 /* must be the last device in the syspath */
535 name
= udev_device_get_sysname(dev
);
536 if (startswith(name
, "nst") && strchr("lma", name
[3]) != NULL
)
537 path_prepend(path
, "nst%c", name
[3]);
538 else if (startswith(name
, "st") && strchr("lma", name
[2]) != NULL
)
539 path_prepend(path
, "st%c", name
[2]);
542 static struct udev_device
*handle_usb(struct udev_device
*parent
, char **path
) {
547 devtype
= udev_device_get_devtype(parent
);
550 if (!streq(devtype
, "usb_interface") && !streq(devtype
, "usb_device"))
553 str
= udev_device_get_sysname(parent
);
554 port
= strchr(str
, '-');
559 parent
= skip_subsystem(parent
, "usb");
560 path_prepend(path
, "usb-0:%s", port
);
564 static struct udev_device
*handle_bcma(struct udev_device
*parent
, char **path
) {
568 sysname
= udev_device_get_sysname(parent
);
569 if (sscanf(sysname
, "bcma%*u:%u", &core
) != 1)
572 path_prepend(path
, "bcma-%u", core
);
576 static struct udev_device
*handle_ccw(struct udev_device
*parent
, struct udev_device
*dev
, char **path
) {
577 struct udev_device
*scsi_dev
;
583 scsi_dev
= udev_device_get_parent_with_subsystem_devtype(dev
, "scsi", "scsi_device");
584 if (scsi_dev
!= NULL
) {
589 hba_id
= udev_device_get_sysattr_value(scsi_dev
, "hba_id");
590 wwpn
= udev_device_get_sysattr_value(scsi_dev
, "wwpn");
591 lun
= udev_device_get_sysattr_value(scsi_dev
, "fcp_lun");
592 if (hba_id
!= NULL
&& lun
!= NULL
&& wwpn
!= NULL
) {
593 path_prepend(path
, "ccw-%s-zfcp-%s:%s", hba_id
, wwpn
, lun
);
598 path_prepend(path
, "ccw-%s", udev_device_get_sysname(parent
));
600 parent
= skip_subsystem(parent
, "ccw");
604 static int builtin_path_id(struct udev_device
*dev
, int argc
, char *argv
[], bool test
) {
605 struct udev_device
*parent
;
607 bool supported_transport
= false;
608 bool supported_parent
= false;
613 parent
= udev_device_get_parent_with_subsystem_devtype(dev
, "ccw", NULL
);
614 if (parent
!= NULL
) {
615 handle_ccw(parent
, dev
, &path
);
619 /* walk up the chain of devices and compose path */
621 while (parent
!= NULL
) {
624 subsys
= udev_device_get_subsystem(parent
);
625 if (subsys
== NULL
) {
627 } else if (streq(subsys
, "scsi_tape")) {
628 handle_scsi_tape(parent
, &path
);
629 } else if (streq(subsys
, "scsi")) {
630 parent
= handle_scsi(parent
, &path
, &supported_parent
);
631 supported_transport
= true;
632 } else if (streq(subsys
, "cciss")) {
633 parent
= handle_cciss(parent
, &path
);
634 supported_transport
= true;
635 } else if (streq(subsys
, "usb")) {
636 parent
= handle_usb(parent
, &path
);
637 supported_transport
= true;
638 } else if (streq(subsys
, "bcma")) {
639 parent
= handle_bcma(parent
, &path
);
640 supported_transport
= true;
641 } else if (streq(subsys
, "serio")) {
642 path_prepend(&path
, "serio-%s", udev_device_get_sysnum(parent
));
643 parent
= skip_subsystem(parent
, "serio");
644 } else if (streq(subsys
, "pci")) {
645 path_prepend(&path
, "pci-%s", udev_device_get_sysname(parent
));
646 parent
= skip_subsystem(parent
, "pci");
647 supported_parent
= true;
648 } else if (streq(subsys
, "platform")) {
649 path_prepend(&path
, "platform-%s", udev_device_get_sysname(parent
));
650 parent
= skip_subsystem(parent
, "platform");
651 supported_transport
= true;
652 supported_parent
= true;
653 } else if (streq(subsys
, "acpi")) {
654 path_prepend(&path
, "acpi-%s", udev_device_get_sysname(parent
));
655 parent
= skip_subsystem(parent
, "acpi");
656 supported_parent
= true;
657 } else if (streq(subsys
, "xen")) {
658 path_prepend(&path
, "xen-%s", udev_device_get_sysname(parent
));
659 parent
= skip_subsystem(parent
, "xen");
660 supported_parent
= true;
661 } else if (streq(subsys
, "scm")) {
662 path_prepend(&path
, "scm-%s", udev_device_get_sysname(parent
));
663 parent
= skip_subsystem(parent
, "scm");
664 supported_transport
= true;
665 supported_parent
= true;
669 parent
= udev_device_get_parent(parent
);
673 * Do not return devices with an unknown parent device type. They
674 * might produce conflicting IDs if the parent does not provide a
675 * unique and predictable name.
677 if (!supported_parent
)
681 * Do not return block devices without a well-known transport. Some
682 * devices do not expose their buses and do not provide a unique
683 * and predictable name that way.
685 if (streq(udev_device_get_subsystem(dev
), "block") && !supported_transport
)
690 char tag
[UTIL_NAME_SIZE
];
694 /* compose valid udev tag name */
695 for (p
= path
, i
= 0; *p
; p
++) {
696 if ((*p
>= '0' && *p
<= '9') ||
697 (*p
>= 'A' && *p
<= 'Z') ||
698 (*p
>= 'a' && *p
<= 'z') ||
704 /* skip all leading '_' */
708 /* avoid second '_' */
714 /* strip trailing '_' */
715 while (i
> 0 && tag
[i
-1] == '_')
719 udev_builtin_add_property(dev
, test
, "ID_PATH", path
);
720 udev_builtin_add_property(dev
, test
, "ID_PATH_TAG", tag
);
727 const struct udev_builtin udev_builtin_path_id
= {
729 .cmd
= builtin_path_id
,
730 .help
= "Compose persistent device path",