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, ...)
43 err = vasprintf(&pre, fmt, va);
51 err = asprintf(&new, "%s-%s", pre, *path);
65 ** Linux only supports 32 bit luns.
66 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
68 static int format_lun_number(struct udev_device *dev, char **path)
70 unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
72 /* address method 0, peripheral device addressing with bus id of zero */
74 return path_prepend(path, "lun-%lu", lun);
75 /* handle all other lun addressing methods by using a variant of the original lun format */
76 return path_prepend(path, "lun-0x%04lx%04lx00000000", lun & 0xffff, (lun >> 16) & 0xffff);
79 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys)
81 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)
97 struct udev *udev = udev_device_get_udev(parent);
98 struct udev_device *targetdev;
99 struct udev_device *fcdev = NULL;
103 targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
104 if (targetdev == NULL)
107 fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
110 port = udev_device_get_sysattr_value(fcdev, "port_name");
116 format_lun_number(parent, &lun);
117 path_prepend(path, "fc-%s-%s", port, lun);
121 udev_device_unref(fcdev);
125 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
127 struct udev *udev = udev_device_get_udev(parent);
128 struct udev_device *targetdev;
129 struct udev_device *target_parent;
130 struct udev_device *sasdev;
131 const char *sas_address;
134 targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
135 if (targetdev == NULL)
138 target_parent = udev_device_get_parent(targetdev);
139 if (target_parent == NULL)
142 sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
143 udev_device_get_sysname(target_parent));
147 sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
148 if (sas_address == NULL) {
153 format_lun_number(parent, &lun);
154 path_prepend(path, "sas-%s-%s", sas_address, lun);
158 udev_device_unref(sasdev);
162 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path)
164 struct udev *udev = udev_device_get_udev(parent);
165 struct udev_device *transportdev;
166 struct udev_device *sessiondev = NULL;
169 struct udev_device *conndev = NULL;
174 /* find iscsi session */
175 transportdev = parent;
177 transportdev = udev_device_get_parent(transportdev);
178 if (transportdev == NULL)
180 if (startswith(udev_device_get_sysname(transportdev), "session"))
184 /* find iscsi session device */
185 sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
186 if (sessiondev == NULL)
188 target = udev_device_get_sysattr_value(sessiondev, "targetname");
189 if (target == NULL) {
194 if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
198 conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
200 if (conndev == NULL) {
204 addr = udev_device_get_sysattr_value(conndev, "persistent_address");
205 port = udev_device_get_sysattr_value(conndev, "persistent_port");
206 if (addr == NULL || port == NULL) {
211 format_lun_number(parent, &lun);
212 path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
216 udev_device_unref(sessiondev);
217 udev_device_unref(conndev);
221 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path)
223 struct udev_device *hostdev;
224 int host, bus, target, lun;
232 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
236 name = udev_device_get_sysname(parent);
237 if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
241 * Rebase host offset to get the local relative number
243 * Note: This is by definition racy, unreliable and too simple.
244 * Please do not copy this model anywhere. It's just a left-over
245 * from the time we had no idea how things should look like in
248 * Making assumptions about a global in-kernel counter and use
249 * that to calculate a local offset is a very broken concept. It
250 * can only work as long as things are in strict order.
252 * The kernel needs to export the instance/port number of a
253 * controller directly, without the need for rebase magic like
254 * this. Manual driver unbind/bind, parallel hotplug/unplug will
255 * get into the way of this "I hope it works" logic.
258 base = strdup(udev_device_get_syspath(hostdev));
261 pos = strrchr(base, '/');
272 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
276 if (dent->d_name[0] == '.')
278 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
280 if (!startswith(dent->d_name, "host"))
282 i = strtoul(&dent->d_name[4], &rest, 10);
286 * find the smallest number; the host really needs to export its
287 * own instance number per parent device; relying on the global host
288 * enumeration and plainly rebasing the numbers sounds unreliable
290 if (basenum == -1 || i < basenum)
300 path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
306 static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char **path) {
307 struct udev_device *hostdev;
308 struct udev_device *vmbusdev;
309 const char *guid_str;
314 hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
318 vmbusdev = udev_device_get_parent(hostdev);
322 guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
326 if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
329 for (i = 1, k = 0; i < 36; i++) {
330 if (guid_str[i] == '-')
332 guid[k++] = guid_str[i];
336 format_lun_number(parent, &lun);
337 path_prepend(path, "vmbus-%s-%s", guid, lun);
342 static struct udev_device *handle_scsi(struct udev_device *parent, char **path)
348 devtype = udev_device_get_devtype(parent);
349 if (devtype == NULL || !streq(devtype, "scsi_device"))
353 id = udev_device_get_sysattr_value(parent, "ieee1394_id");
355 parent = skip_subsystem(parent, "scsi");
356 path_prepend(path, "ieee1394-0x%s", id);
360 /* scsi sysfs does not have a "subsystem" for the transport */
361 name = udev_device_get_syspath(parent);
363 if (strstr(name, "/rport-") != NULL) {
364 parent = handle_scsi_fibre_channel(parent, path);
368 if (strstr(name, "/end_device-") != NULL) {
369 parent = handle_scsi_sas(parent, path);
373 if (strstr(name, "/session") != NULL) {
374 parent = handle_scsi_iscsi(parent, path);
379 * We do not support the ATA transport class, it uses global counters
380 * to name the ata devices which numbers spread across multiple
383 * The real link numbers are not exported. Also, possible chains of ports
384 * behind port multipliers cannot be composed that way.
386 * Until all that is solved at the kernel level, there are no by-path/
387 * links for ATA devices.
389 if (strstr(name, "/ata") != NULL) {
394 if (strstr(name, "/vmbus_") != NULL) {
395 parent = handle_scsi_hyperv(parent, path);
399 parent = handle_scsi_default(parent, path);
404 static struct udev_device *handle_cciss(struct udev_device *parent, char **path)
407 unsigned int controller, disk;
409 str = udev_device_get_sysname(parent);
410 if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
413 path_prepend(path, "cciss-disk%u", disk);
414 parent = skip_subsystem(parent, "cciss");
418 static void handle_scsi_tape(struct udev_device *dev, char **path)
422 /* must be the last device in the syspath */
426 name = udev_device_get_sysname(dev);
427 if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
428 path_prepend(path, "nst%c", name[3]);
429 else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
430 path_prepend(path, "st%c", name[2]);
433 static struct udev_device *handle_usb(struct udev_device *parent, char **path)
439 devtype = udev_device_get_devtype(parent);
442 if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
445 str = udev_device_get_sysname(parent);
446 port = strchr(str, '-');
451 parent = skip_subsystem(parent, "usb");
452 path_prepend(path, "usb-0:%s", port);
456 static struct udev_device *handle_bcma(struct udev_device *parent, char **path)
461 sysname = udev_device_get_sysname(parent);
462 if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
465 path_prepend(path, "bcma-%u", core);
469 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path)
471 struct udev_device *scsi_dev;
473 scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
474 if (scsi_dev != NULL) {
479 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
480 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
481 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
482 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
483 path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
488 path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
490 parent = skip_subsystem(parent, "ccw");
494 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test)
496 struct udev_device *parent;
498 bool some_transport = false;
501 parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
502 if (parent != NULL) {
503 handle_ccw(parent, dev, &path);
507 /* walk up the chain of devices and compose path */
509 while (parent != NULL) {
512 subsys = udev_device_get_subsystem(parent);
513 if (subsys == NULL) {
515 } else if (streq(subsys, "scsi_tape")) {
516 handle_scsi_tape(parent, &path);
517 } else if (streq(subsys, "scsi")) {
518 parent = handle_scsi(parent, &path);
519 some_transport = true;
520 } else if (streq(subsys, "cciss")) {
521 parent = handle_cciss(parent, &path);
522 some_transport = true;
523 } else if (streq(subsys, "usb")) {
524 parent = handle_usb(parent, &path);
525 some_transport = true;
526 } else if (streq(subsys, "bcma")) {
527 parent = handle_bcma(parent, &path);
528 some_transport = true;
529 } else if (streq(subsys, "serio")) {
530 path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
531 parent = skip_subsystem(parent, "serio");
532 } else if (streq(subsys, "pci")) {
533 path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
534 parent = skip_subsystem(parent, "pci");
535 } else if (streq(subsys, "platform")) {
536 path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
537 parent = skip_subsystem(parent, "platform");
538 some_transport = true;
539 } else if (streq(subsys, "acpi")) {
540 path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
541 parent = skip_subsystem(parent, "acpi");
542 } else if (streq(subsys, "xen")) {
543 path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
544 parent = skip_subsystem(parent, "xen");
545 } else if (streq(subsys, "scm")) {
546 path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
547 parent = skip_subsystem(parent, "scm");
548 some_transport = true;
551 parent = udev_device_get_parent(parent);
555 * Do not return a single-parent-device-only for block
556 * devices, they might have entire buses behind it which
557 * do not get unique IDs only by using the parent device.
559 if (!some_transport && streq(udev_device_get_subsystem(dev), "block")) {
566 char tag[UTIL_NAME_SIZE];
570 /* compose valid udev tag name */
571 for (p = path, i = 0; *p; p++) {
572 if ((*p >= '0' && *p <= '9') ||
573 (*p >= 'A' && *p <= 'Z') ||
574 (*p >= 'a' && *p <= 'z') ||
580 /* skip all leading '_' */
584 /* avoid second '_' */
590 /* strip trailing '_' */
591 while (i > 0 && tag[i-1] == '_')
595 udev_builtin_add_property(dev, test, "ID_PATH", path);
596 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
603 const struct udev_builtin udev_builtin_path_id = {
605 .cmd = builtin_path_id,
606 .help = "compose persistent device path",