9 The udev database has changed, After installation of a new udev
10 version, 'udevadm info --convert-db' should be called, to let the new
11 udev/libudev version read the already stored data.
13 udevadm now supports quoting of property values, and prefixing of
15 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
23 udev_device_get_is_initialized()
24 udev_enumerate_add_match_is_initialized()
25 to be able to skip devices the kernel has created , but udev has
29 udev_device_get_usec_since_initialized()
30 to retrieve the "age" of a udev device record.
32 GUdev supports a more generic GUdevEnumerator class, udev TAG
33 handling, device initialization and timestamp now.
35 The counterpart of /sys/dev/{char,block}/$major:$minor,
36 /dev/{char,block}/$major:$minor symlinks are now unconditionally
37 created, even when no rule files exist.
39 New and updated keymaps.
45 GUdev moved from /usr to /.
55 Persistent network naming rules are disabled inside of Qemu/KVM now.
57 New and updated keymaps.
59 Udev gets unconditionally enabled on systemd installations now. There
60 is no longer the need to to run 'systemctl enable udev.service'.
74 New and fixed keymaps.
76 Install systemd service files if applicable.
82 All distribution specific rules are removed from the udev source tree,
83 most of them are no longer needed. The Gentoo rules which allow to support
84 older kernel versions, which are not covered by the default rules anymore
85 has moved to rules/misc/30-kernel-compat.rules.
91 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
92 was removed from udevd.
94 Udevd now checks the kernel commandline for the following variables:
95 udev.log-priority=<syslog priority>
96 udev.children-max=<maximum number of workers>
97 udev.exec-delay=<seconds to delay the execution of RUN=>
98 to help debuging coldplug setups where the loading of a kernel
99 module crashes the system.
101 The subdirectory in the source tree rules/packages has been renamed to
102 rules/arch, anc contains only architecture specific rules now.
112 Now the udev daemon itself, does on startup:
113 - copy the content of /lib/udev/devices to /dev
114 - create the standard symlinks like /dev/std{in,out,err},
115 /dev/core, /dev/fd, ...
116 - use static node information provided by kernel modules
117 and creates these nodes to allow module on-demand loading
118 - possibly apply permissions to all ststic nodes from udev
119 rules which are annotated to match a static node
121 The default mode for a device node is 0600 now to match the kernel
122 created devtmpfs defaults. If GROUP= is specified and no MODE= is
123 given the default will be 0660.
129 Udev now gradually starts to pass control over the primary device nodes
130 and their names to the kernel, and will in the end only manage the
131 permissions of the node, and possibly create additional symlinks.
132 As a first step NAME="" will be ignored, and NAME= setings with names
133 other than the kernel provided name will result in a logged warning.
134 Kernels that don't provide device names, or devtmpfs is not used, will
135 still work as they did before, but it is strongly recommended to use
136 only the same names for the primary device node as the recent kernel
137 provides for all devices.
141 Fix broken firmware loader search path.
147 "udevadm trigger" defaults to "change" events now instead of "add"
148 events. The "udev boot script" might need to add "--action=add" to
149 the trigger command if not already there, in case the initial coldplug
150 events are expected as "add" events.
152 The option "all_partitons" was removed from udev. This should not be
153 needed for usual hardware. Udev can not safely make assumptions
154 about non-existing partition major/minor numbers, and therefore no
155 longer provide this unreliable and unsafe option.
157 The option "ignore_remove" was removed from udev. With devtmpfs
158 udev passed control over device nodes to the kernel. This option
159 should not be needed, or can not work as advertised. Neither
160 udev nor the kernel will remove device nodes which are copied from
161 the /lib/udev/devices/ directory.
163 All "add|change" matches are replaced by "!remove" in the rules and
164 in the udev logic. All types of events will update possible symlinks
165 and permissions, only "remove" is handled special now.
167 The modem modeswitch extra was removed and the external usb_modeswitch
168 program should be used instead.
170 New and fixed keymaps.
180 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
181 depend on the current sysfs layout and the information not available in the
182 deprecated layout. All remaining support for the deprecated sysfs layout is
187 Fix for a possible endless loop in the new input_id program.
193 The option "ignore_device" does no longer exist. There is no way to
194 ignore an event, as libudev events can not be suppressed by rules.
195 It only prevented RUN keys from being executed, which results in an
196 inconsistent behavior in current setups.
198 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
199 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
202 The support for the deprecated IDE devices has been removed from the
203 default set of rules. Distros who still care about non-libata drivers
204 need to add the rules to the compat rules file.
206 The ID_CLASS property on input devices has been replaced by the more accurate
207 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
208 determined by the new "input_id" prober now. Some devices, such as touchpads,
209 can have several classes. So if you previously had custom udev rules which e. g.
210 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
211 ENV{ID_INPUT_KEYBOARD}=="?*".
217 To support DEVPATH strings larger than the maximum file name length, the
218 private udev database format has changed. If some software still reads the
219 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
220 Please do not port anything to the new format again, everything in /dev/.udev
221 is and always was private to udev, and may and will change any time without
224 Multiple devices claiming the same names in /dev are limited to symlinks
225 only now. Mixing identical symlink names and node names is not supported.
226 This reduces the amount of data in the database significantly.
228 NAME="%k" causes a warning now. It's is and always was completely superfluous.
229 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
232 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
233 if they are not the default. To support older kernels, the NAME= rules need to
234 be added to the compat rules file.
236 Symlinks to udevadm with the old command names are no longer resolved to
237 the udevadm commands.
239 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
242 The option "last_rule" does no longer exist. Its use breaks too many
243 things which expect to be run from independent later rules, and is an idication
244 that something needs to be fixed properly instead.
246 The gudev API is no longer marked as experimental,
247 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
248 is enabled by default now. Various projects already depend on introspection
249 information to bind dynamic languages to the gudev interfaces.
255 The udevadm trigger "--retry-failed" option, which is replaced since quite
256 a while by "--type=failed" is removed.
258 The failed tracking was not working at all for a few releases. The RUN
259 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
260 default is not to track any failing RUN executions.
262 New keymaps, new modem, hid2hci updated.
266 Fix possible crash in udevd when worker processes are busy, rules are
267 changed at the same time, and workers get killed to reload the rules.
273 Properties set with ENV{.FOO}="bar" are marked private by starting the
274 name with a '.'. They will not be stored in the database, and not be
275 exported with the event.
277 Firmware files are looked up in:
278 /lib/firmware/updates/$(uname -r)
279 /lib/firmware/updates
280 /lib/firmware/$(uname -r)
284 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
285 ata_id, instead of scsi_id, is the default tool now for ATA devices.
291 The configure options have changed because another library needs to be
292 installed in a different location. Instead of exec_prefix and udev_prefix,
293 libdir, rootlibdir and libexecdir are used. The Details are explained in
296 Event processes now get re-used after they handled an event. This reduces
297 the number of forks and the pressure on the CPU significantly, because
298 cloned event processes no longer cause page faults in the main daemon.
299 After the events have settled, a few worker processes stay around for
300 future events, all others get cleaned up.
302 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
303 Also inotify support is mandatory now to run udev.
305 The format of the queue exported by the udev damon has changed. There is
306 no longer a /dev/.udev/queue/ directory. The current event queue can be
307 accessed with udevadm settle and libudedv.
309 Libudev does not have the unstable API header anymore. From now on,
310 incompatible changes will be handled by bumping the library major version.
312 To build udev from the git tree gtk-doc is needed now. The tarballs will
313 build without it and contain the pre-built documentation. An online copy
315 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
317 The tools from the udev-extras repository have been merged into the main
318 udev repository. Some of the extras have larger external dependencies, and
319 they can be disabled with the configure switch --disable-extras.
325 The program vol_id and the library libvolume_id are removed from the
326 repository. Libvolume_id is merged with libblkid from the util-linux-ng
327 package. Persistent disk links for label and uuid depend on the
328 util-linux-ng version (2.15) of blkid now. Older versions of blkid
329 can not be used with udev.
331 Libudev allows to subscribe to udev events. To prevent unwanted messages
332 to be delivered, and waking up the subscribing process, a filter can be
333 installed, to drop messages inside a kernel socket filter. The filters
334 match on the <subsytem>:<devtype> properties of the device.
335 This is part of the ongoing effort to replace HAL, and switch current
336 users over to directly use libudev.
337 Libudev is still marked as experimental, and its interface might
338 eventually change if needed, but no major changes of the currently exported
339 interface are expected anymore, and a first stable release should happen
342 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
343 is not supported since while and udevd will log an error message at
344 startup. It should still be able to boot-up, but advanced rules and system
345 services which depend on the information not available in the old sysfs
346 format will fail to work correctly.
348 DVB device naming is supplied by the kernel now. In case older kernels
349 need to be supported, the old shell script should be added to a compat
356 The processed udev events get send back to the netlink socket. Libudev
357 provides access to these events. This is work-in-progress, to replace
358 the DeviceKit daemon functionality directly with libudev. There are
359 upcoming kernel changes to allow non-root users to subcribe to these
366 "udevadm settle" now optionally accepts a range of events to wait for,
367 instead of waiting for "all" events.
373 The installed watch for block device metadata changes is now removed
374 during event hadling, because some (broken) tools may be called from udev
375 rules and (wrongly) open the device with write access. After the finished
376 event handling the watch is restored.
382 Device nodes can be watched for changes with inotify with OPTIONS="watch".
383 If closed after being opened for writing, a "change" uevent will occur.
384 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
390 The udevadm test command has no longer a --force option, nodes and symlinks
391 are always updated with a test run now.
393 The udevd daemon can be started with --resolve-names=never to avoid all user
394 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
395 lookup user and groups every time events are handled.
401 We are currently merging the Ubuntu rules in the udev default rules,
402 and get one step closer to provide a common Linux /dev setup, regarding
403 device names, symlinks, and default device permissions. On udev startup,
404 we now expect the following groups to be resolvable to their ids with
406 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
407 LDAP setups need to make sure, that these groups are always resolvable at
408 bootup, with only the rootfs mounted, and without network access available.
410 Some systems may need to add some new, currently not used groups, or need
411 to add some users to new groups, but the cost of this change is minimal,
412 compared to the pain the current, rather random, differences between the
413 various distributions cause for upstream projects and third-party vendors.
415 In general, "normal" users who log into a machine should never be a member
416 of any such group, but the device-access should be managed by dynamic ACLs,
417 which get added and removed for the specific users on login/logout and
418 session activity/inactivity. These groups are only provided for custom setups,
419 and mainly system services, to allow proper privilege separation.
420 A video-streaming daemon uid would be a member of "audio" and "video", to get
421 access to the sound and video devices, but no "normal" user should ever belong
422 to the "audio" group, because he could listen to the built-in microphone with
423 any ssh-session established from the other side of the world.
425 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
426 which do not depend on the kernel device name. As usual, unique
427 devices - only a single one per product connected, or a real
428 USB serial number in the device - are always found with the same
429 name in the by-id/ directory.
430 Completely identical devices may overwrite their names in by-id/
431 and can only be found reliably in the by-path/ directory. Devices
432 specified by by-path/ must not change their connection, like the
433 USB port number they are plugged in, to keep their name.
435 To support some advanced features, Linux 2.6.22 is the oldest supported
436 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
437 supported. Older kernels should still work, and devices nodes should be
438 reliably created, but some rules and libudev will not work correctly because
439 the old kernels do not provide the expected information or interfaces.
445 Fix for a possible segfault while swapping network interface names in udev
452 The group "video" is part of the default rules now.
456 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
457 block devices in some cases. No common distro uses this option anymore,
458 and we do not get enough testing for this and recent udev versions. If
459 this option is not needed to run some old distro with a new kernel,
460 it should be disabled in the kernel config.
462 Bugfix for the $links substitution variable, which may crash if no links
463 are created. This should not happen in usual setups because we always
464 create /dev/{block,char}/ links.
466 The strings of the parsed rules, which are kept in memory, no longer
467 contain duplicate entries, or duplicate tails of strings. This, and the
468 new rules parsing/matching code reduces the total in-memory size of
469 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
472 The export of DEVTYPE=disk/partition got removed from the default
473 rules. This value is available from the kernel. The pnp shell script
474 modprobe hack is removed from the default rules. ACPI devices have _proper_
475 modalias support and take care of the same functionality.
476 Installations which support old kernels, but install current default
477 udev rules may want to add that to the compat rules file.
479 Libvolume_id now always probes for all known filesystems, and does not
480 stop at the first match. Some filesystems are marked as "exclusive probe",
481 and if any other filesytem type matches at the same time, libvolume_id
482 will, by default, not return any probing result. This is intended to prevent
483 mis-detection with conflicting left-over signatures found from earlier
484 file system formats. That way, we no longer depend on the probe-order
485 in case of multiple competing signatures. In some setups the kernel allows
486 to mount a volume with just the old filesystem signature still in place.
487 This may damage the new filesystem and cause data-loss, just by mounting
488 it. Because volume_id can not decide which one the correct signature is,
489 the wrong signatures need to be removed manually from the volume, or the
490 volume needs to be reformatted, to enable filesystem detection and possible
495 Fix segfault if compiled without optimization and dbg() does not get
496 compiled out and uses variables which are not available.
500 Bugfixes. (And maybe new bugs. :))
502 The rule matching engine got converted from a rule list to a token
503 array which reduced the in-memory rules representation of a full
504 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
505 Limits like 5 ENV and ATTR matches, and one single instance for most
506 other keys per rule are gone.
508 The NAME assignment is no longer special cased. If later rules assign
509 a NAME value again, the former value will be overwritten. As usual
510 for most other keys, the NAME value can be protected by doing a final
511 assignment with NAME:="<value>".
513 All udev code now uses libudev, which is also exported. The library
514 is still under development, marked as experimental, and its interface
515 may change as long as the DeviceKit integration is not finished.
517 Many thanks to Alan Jenkins for his continuous help, and finding and
518 optimizing some of the computing expensive parts.
524 Kernel devices and device nodes are connected now by reverse indizes in
525 /sys and /dev. A device number retrieved by a stat() or similar, the
526 kernel device directory can be found by looking up:
527 /sys/dev/{block,char}/<maj>:<min>
528 and the device node of the same device by looking up:
529 /dev/{block,char}/<maj>:<min>
533 Fix recently introduced bug, which caused a compilation without large
534 file support, where vol_id does not recognize raid signatures at the end
537 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
538 Seems some kernel versions prevent the creation of the ieee-* links,
539 so people used the scsi-* link which disappeared now.
541 More libudev work. Almost all udevadm functionality comes from libudev
544 udevadm trigger has a new option --type, which allows to trigger events
545 for "devices", for "subsystems", or "failed" devices. The old option
546 --retry-failed" still works, but is no longer mentioned in the man page.
552 The udevadm info --device-id-of-file= output has changed to use
553 the obvious format. Possible current users should use the --export
554 option which is not affected.
556 The old udev commands symlinks to udevadm are not installed, if
557 these symlinks are used, a warning is printed.
563 Optical drive's media is no longer probed for raid signatures,
564 reading the end of the device causes some devices to malfunction.
565 Also the offset of the last session found is used now to probe
568 The volume_id library got a major version number update to 1,
569 some deprecated functions are removed.
571 A shared library "libudev" gets installed now to provide access
572 to udev device information. DeviceKit, the successor of HAL, will
573 need this library to access the udev database and search sysfs for
575 The library is currently in an experimental state, also the API is
576 expected to change, as long as the DeviceKit integration is not
581 We use ./configure now. See INSTALL for details. Current
584 "/usr" - prefix for man pages, include files
586 "" - the root filesystem, prefix for libs and binaries
590 "lib" - directory name for libraries, not a path name
591 multilib 64bit systems may use "lib64" instead of "lib"
593 compile-in verbose debug messages
595 disable all logging and compile-out all log strings
597 link against SELInux libraries, to set the expected context
600 In the default rules, the group "disk" gets permissions 0660 instead
601 of 0640. One small step closer to unify distro rules. Some day, all
602 distros hopefully end up with the same set of rules.
604 No symlinks to udevadm are installed anymore, if they are still needed,
605 they should be provided by the package.
611 Default udev rules, which are not supposed to be edited by the user, should
612 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
613 the udev package and will be replaced with an update. Udev will pick up rule
615 /lib/udev/rules.d/ - default installed rules
616 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
617 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
618 It does not matter in which directory a rule file lives, all files are sorted
621 To help creating /dev/root, we have now:
622 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
625 In case the current --device-id-of-file is already used, please switch to
626 the --export format version, it saves the output parsing and the old
627 format will be changed to use ':' as a separator, like the format in the
632 Fix cdrom_id to properly recognize blank media.
638 Tape drive id-data is queried from /dev/bsg/* instead of the tape
639 nodes. This avoids rewinding tapes on open().
645 The symlinks udevcontrol and udevtrigger are no longer installed by
648 The scsi_id program does not depend on sysfs anymore. It can speak
649 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
650 data, which should solve some old problems with tape devices, where
651 we better do not open all tape device nodes to identify the device.
657 The cdrom_id program is replaced by an advanced version, which can
658 detect most common device types, and also properties of the inserted
659 media. This is part of moving some basic functionality from HAL into
660 udev (and the kernel).
666 The last WAIT_FOR_SYSFS rule is removed from the default rules.
668 The symlinks to udevadm for the debugging tools: udevmonitor and
669 udevtest are no longer created.
671 The symlinks to the udevadm man page for the old tool names are
674 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
675 should be prefixed with '@' to indicate that the path is not a
686 Udevstart is removed from the tree, it did not get installed for
687 a long time now, and is long replaced by trigger and settle.
693 All udev tools are merged into a single binary called udevadm.
694 The old names of the tools are built-in commands in udevadm now.
695 Symlinks to udevadm, with the names of the old tools, provide
696 the same functionality as the standalone tools. There is also
697 only a single udevadm.8 man page left for all tools.
699 Tools like mkinitramfs should be checked, if they need to include
700 udevadm in the list of files.
710 The etc/udev/rules.d/ directory now contains a default set of basic
711 udev rules. This initial version is the result of a rules file merge
712 of Fedora and openSUSE. For these both distros only a few specific
713 rules are left in their own file, named after the distro. Rules which
714 are optionally installed, because they are only valid for a specific
715 architecture, or rules for subsystems which are not always used are
716 in etc/udev/packages/.
722 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
723 actions by dynamically created rules.
725 SYMLINK=="<value>" matches agains the entries in the list of
726 currently defined symlinks. The links are not created in the
727 filesystem at that point in time, but the values can be matched.
729 RUN{ignore_error}+="<program>" will ignore any exit code from the
730 program and not record as a failed event.
736 Final merge of patches/features from the Ubuntu package.
742 Control characters in filesystem label strings are no longer silenty
743 removed, but hex-encoded, to be able to uniquely identify the device
744 by its symlink in /dev/disk/by-label/.
745 If libvolume_id is used by mount(8), LABEL= will work as expected,
746 if slashes or other characters are used in the label string.
748 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
749 can be specified now. The TEST key accepts an optional mode mask
750 TEST{0100}=="<is executable file>".
752 Scsi_id now supports a mode without expecting scsi-specific sysfs
753 entries to allow the extraction of cciss-device persistent properties.
759 In the future, we may see uuid's which are just simple character
760 strings (see the DDF Raid Specification). For that reason vol_id now
761 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
762 the creation of symlinks, the *_SAFE values ensure, that no control
763 or whitespace characters are used in the filename.
765 Possible users of libvolume_id, please use the volume_id_get_* functions.
766 The public struct will go away in a future release of the library.
772 Removal of useless extras/eventrecorder.sh.
782 The directory multiplexer for dev.d/ and hotplug.d are finally removed
783 from the udev package.
789 Symlinks can have priorities now, the priority is assigned to the device
790 and specified with OPTIONS="link_priority=100". Devices with higher
791 priorities overwrite the symlinks of devices with lower priorities.
792 If the device that currently owns the link, goes away, the symlink
793 will be removed, and recreated, pointing to the next device with the
794 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
795 more reliable, if multiple devices contain the same metadata and overwrite
798 The dasd_id program is removed from the udev tree, and dasdinfo, with the
799 needed rules, are part of the s390-tools now.
801 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
802 we may get the scsi sysfs mess fixed some day, and this will only catch
803 the devices we are looking for.
805 USB serial numbers for storage devices have the target:lun now appended,
806 to make it possibble to distinguish broken multi-lun devices with all
807 the same SCSI identifiers.
809 Note: The extra "run_directory" which searches and executes stuff in
810 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
811 with the next release. Make sure, that you don't use it anymore, or
812 provides your own implementation of that inefficient stuff.
813 We are tired of reports about a "slow udev", because these directories
814 contain stuff, that runs with _every_ event, instead of using rules,
815 that run programs only for the matching events.
825 DRIVER== will match only for devices that actually have a real
826 driver. DRIVERS== must be used, if parent devices should be
827 included in the match.
829 Libvolume_id's "linux_raid" detection needed another fix.
837 Add additional check to volume_id detection of via_raid, cause
838 some company decided to put a matching pattern all over the empty
839 storage area of their music players.
843 Fix path_id for SAS devices.
847 The udev daemon can be started with --debug-trace now, which will
848 execute all events serialized to get a chance to catch a possible
849 action that crashes the box.
851 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
852 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
853 are excluded from the warning. Referencing parent attributes directly
854 may break when something in the kernel driver model changes. Udev will
855 just find the attribute by walking up the parent chain.
857 Udevtrigger now sorts the list of devices depending on the device
858 dependency, so a "usb" device is triggered after the parent "pci"
863 Revert persistent-storage ata-serial '_' '-' replacement.
869 Udevtrigger can now filter the list of devices to be triggered. Matches
870 for subsystems or sysfs attributes can be specified.
872 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
873 zero-sized files to avoid pointing to /sys and confuse broken tools which
874 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
877 The rules and scripts to create udev rules for persistent network
878 devices and optical drives are in the extras/rules_generator directory
879 now. If you use something similar, please consider replacing your own
880 version with this, to share the support effort. The rule_generator
881 installs its own rules into /etc/udev/rules.d.
883 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
884 the rule_generator depends on cdrom_id to be called in an earlier rule.
890 Renaming of some key names (the old names still work):
891 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
892 (The behavior of the key DRIVER will change soon in one of the next
893 releases, to match only the event device, please switch to DRIVERS
894 instead. If DRIVER is used, it will behave like DRIVERS, but an error
896 With the new key names, we have a more consistent and simpler scheme.
897 We can match the properties of the event device only, with: KERNEL,
898 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
899 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
900 longer mentioned in the man page and should be switched in the rule
903 ATTR{file}="value" can be used now, to write to a sysfs file of the
904 event device. Instead of:
905 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
907 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
909 All the PHYSDEV* keys are deprecated and will be removed from a
911 PHYDEVPATH - is the path of a parent device and should not be
913 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
914 matched with SUBSYSTEMS==
915 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
916 Newer kernels will have DRIVER in the environment,
917 for older kernels udev puts in. Class device will
918 no longer carry this property of a parent and
919 DRIVERS== can be used to match such a parent value.
920 Note that ENV{DRIVER} is only available for a few bus devices, where
921 the driver is already bound at device event time. On coldplug, the
922 events for a lot devices are already bound to a driver, and they will have
923 that value set. But on hotplug, at the time the kernel creates the device,
924 it can't know what driver may claim the device after that, therefore
925 in most cases it will be empty.
927 Failed events should now be re-triggered with:
928 udevtrigger --retry-failed.
929 Please switch to this command, so we keep the details of the /dev/.udev/failed/
930 files private to the udev tools. We may need to switch the current symlink
931 target, cause some obviously broken tools try to scan all files in /dev
932 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
933 million times. This takes ages on slow boxes.
935 The udevinfo attribute walk (-a) now works with giving a device node
936 name (-n) instead of a devpath (-p). The query now always works, also when
937 no database file was created by udev.
939 The built-in /etc/passwd /etc/group parser is removed, we always depend on
940 getpwnam() and getgrnam() now. One of the next releases will depend on
941 fnmatch() and may use getopt_long().
945 Bugfixes and small improvements.
949 Fix path_id for recent kernels.
955 Added support for swapping network interface names, by temporarily
956 renaming the device and wait for the target name to become free.
960 The built-in MODALIAS key and substitution is removed.
964 The binary firmware helper is replaced by the usual simple
965 shell script. Udevsend is removed from the tree.
973 Some more keys require the correct use of '==' and '=' depending
974 on the kind of operation beeing an assignment or a match. Rules
975 with invalid operations are skipped and logged to syslog. Please
976 test with udevtest if the parsing of your rules throws errors and
977 fix possibly broken rules.
981 Provide "udevsettle" to wait for all current udev events to finish.
982 It also watches the current kernel netlink queue by comparing the
983 even sequence number to make sure that there are no current pending
984 events that have not already arrived in the daemon.
988 Fix rule to skip persistent rules for removable IDE devices, which
989 also skipped optical IDE drives.
991 All *_id program are installed in /lib/udev/ by default now.
993 No binary is stripped anymore as this should be done in the
994 packaging process and not at build time.
996 libvolume_id is provided as a shared library now and vol_id is
997 linked against it. Also one of the next HAL versions will require
998 this library, and the HAL build process will also require the
999 header file to be installed. The copy of the same code in HAL will
1000 be removed to have only a single copy left on the system.
1004 Add persistent links for SCSI tapes. The rules file is renamed
1005 to 60-persistent-storage.rules.
1007 Create persistent path for usb devices. Can be used for all sorts
1008 of devices that can't be distinguished by other properties like
1009 multiple identical keyboards and mice connected to the same box.
1011 Provide "udevtrigger" program to request events on coldplug. The
1012 shell script is much too slow with thousends of devices.
1016 Fix persistent disk rules to exclude removable IDE drives.
1018 Warn if %e, $modalias or MODALIAS is used.
1022 Fix queue export, which wasn't correct for subsequent add/remove
1023 events for the same device.
1027 Fix cramfs detection on big endian.
1029 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1034 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1035 attributes were only checked at the parent device that matched the
1036 by BUS requested subsystem. Fix it to also look at the device we
1037 received the event for.
1039 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1044 Fix a bug where NAME="" would prevent RUN from beeing executed.
1046 RUN="/bin/program" does not longer automatically add the subsystem
1047 as the first parameter. This is from the days of /sbin/hotplug
1048 which is dead now and it's just confusing to need to add a space at
1049 the end of the program name to prevent this.
1050 If you use rules that need the subsystem as the first parameter,
1051 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1052 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1056 The udev man page has moved to udev(7) as it does not describe a command
1057 anymore. The programs udev, udevstart and udevsend are no longer installed
1058 by default and must be copied manually, if they should be installed or
1059 included in a package.
1061 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1062 the ignore rule was applied.
1064 More preparation for future sysfs changes. usb_id and scsi_id no longer
1065 depend on a magic order of devices in the /devices chain. Specific devices
1066 should be requested by their subsytem.
1068 This will always find the scsi parent device without depending on a specific
1070 dev = sysfs_device_get(devpath);
1071 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1073 The "device" link in the current sysfs layout will be automatically
1074 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1075 parent in the devpath. If a device is requested by it's symlink, like all
1076 class devices in the new sysfs layout will look like, it gets automatically
1077 resolved and substituted with the real devpath and not the symlink path.
1080 A similar logic must be applied to _all_ sysfs users, including
1081 scripts, that search along parent devices in sysfs. The explicit use of
1082 the "device" link must be avoided. With the future sysfs layout all
1083 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1084 back to the "class" or the "bus". The layout of the parent devices in
1085 /devices is not necessarily expected to be stable across kernel releases and
1086 searching for parents by their subsystem should make sysfs users tolerant
1087 for changed parent chains.
1091 Prepare udev to work with the experimental kernel patch, that moves
1092 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1094 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1095 moving the class devices to /sys/devices.
1097 Thanks again to Marco for help finding a hopefully nice compromise
1098 to make %b simpler and working again.
1102 Complete removal of libsysfs, replaced by simple helper functions
1103 which are much simpler and a bit faster. The udev daemon operatesentirely
1104 on event parameters and does not use sysfs for simple rules anymore.
1105 Please report any new bugs/problems, that may be caused by this big
1106 change. They will be fixed immediately.
1108 The enumeration format character '%e' is deprecated and will be
1109 removed sometimes from a future udev version. It never worked correctly
1110 outside of udevstart, so we can't use it with the new parallel
1111 coldplug. A simple enumeration is as useless as the devfs naming
1112 scheme, just get rid of both if you still use it.
1114 MODALIAS and $modalias is not needed and will be removed from one of
1115 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1116 the sysfs "modalias" value.
1118 Thanks a lot to Marco for all his help on finding and fixing bugs.
1122 Let scsi_id request libata drive serial numbers from page 0x80.
1124 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1125 added /dev/disk/by-name/* for device mapper device names.
1127 Removed %e from the man page. It never worked reliably outside
1128 of udevstart and udevstart is no longer recommended to use.
1132 Symlinks are now exported to the event environment. Hopefully it's no
1133 longer needed to run udevinfo from an event process, like it was
1134 mentioned on the hotplug list:
1135 UDEV [1134776873.702967] add@/block/sdb
1138 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1142 Fix a problem if udevsend is used as the hotplug handler and tries to use
1143 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1144 and this kind of problems will hopefully go away soon.
1148 All built-in logic to work around bad sysfs timing is removed with this
1149 version. The need to wait for sysfs files is almost fixed with a kernel
1150 version that doesn't work with this udev version anyway. Until we fix
1151 the timing of the "bus" link creation, the former integrated logic should
1152 be emulated by a rule placed before all other rules:
1153 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1155 The option "udev_db" does no longer exist. All udev state will be in
1156 /$udev_root/.udev/ now, there is no longer an option to set this
1158 If the init script or something else used this value, just depend on
1159 this hardcoded path. But remember _all_content_ of this directory is
1160 still private to udev and can change at any time.
1162 Default location for rule sripts and helper programs is now: /lib/udev/.
1163 Everything that is not useful on the commandline should go into this
1164 directory. Some of the helpers in the extras folder are installed there
1165 now. The rules need to be changed, to find the helpers there.
1167 Also /lib/udev/devices is recommended as a directory where packages or
1168 the user can place real device nodes, which get copied over to /dev at
1169 every boot. This should replace the various solutions with custom config
1172 Udevsend does no longer start the udev daemon. This must be done with
1173 the init script that prepares /dev on tmpfs and creates the initial nodes,
1174 before starting the daemon.
1178 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1181 The copy of klibc is removed. A systemwide installed version of klibc
1182 should be used to build a klibc udev now.
1186 NAME="" will not create any nodes, but execute RUN keys. To completely
1187 ignore an event the OPTION "ignore_device" should be used.
1189 After removal of the reorder queue, events with a TIMEOUT can be executed
1190 without any queuing now.
1194 Fixed bug in udevd, if inotify is not available. We depend on netlink
1195 uevents now, kernels without that event source will not work with that
1196 version of udev anymore.
1200 The rule parsing happens now in the daemon once at startup, all udev
1201 event processes inherit the already parsed rules from the daemon.
1202 It is shipped with SUSE10.0 and reduces heavily the system load at
1203 startup. The option to save precompiled rules and let the udev process
1204 pick the them up is removed, as it's no longer needed.
1206 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1207 device. Libsysfs is changed to "translate" the requested link into the
1208 real device path, as it would happen with the hotplug event. Otherwise
1209 device removal and the udev database will not work.
1211 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1214 A few improvements for vol_id, the filesytem probing code.
1218 Fix a stupid typo in extras/run_directory for "make install".
1220 scsi_id creates the temporary devnode now in /dev for usage with a
1221 non-writable /tmp directory.
1223 The uevent kernel socket buffer can carry app. 50.000 events now,
1224 let's see who can break this again. :)
1226 The upcoming kernel will have a new input driver core integration.
1227 Some class devices are now symlinks to the real device. libsysfs
1228 needs a fix for this to work correctly. Udevstart of older udev
1229 versions will _not_ create these devices!
1233 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1238 A bunch of mostly trivial bugfixes. From now on no node name or
1239 symlink name can contain any character than plain whitelisted ascii
1240 characters or validated utf8 byte-streams. This is needed for the
1241 /dev/disk/by-label/* links, because we import untrusted data and
1242 export it to the filesystem.
1246 More bugfixes. If udevd was started from the kernel, we don't
1247 have stdin/stdout/stderr, which broke the forked tools in some
1252 Bugfix. udevstart event ordering was broken for a long time.
1253 The new run_program() uncovered it, because /dev/null was not
1254 available while we try to run external programs.
1255 Now udevstart should create it before we run anything.
1259 Minor bugfixes and some distro rules updates. If you don't have the
1260 persistent disk rules in /dev/disk/by-*/* on your distro, just
1261 grab it from here. :)
1265 We can use socket communication now to pass events from udev to
1267 RUN+="socket:/org/freedesktop/hal/udev_event"
1268 will pass the whole udev event to the HAL daemon without the need
1269 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1273 Mostly bugfixes and see ChangeLog.
1275 The test for the existence of an environment value should be
1277 ENV{KEY}=="*" to ENV{KEY}=="?*"
1278 because "*" will not fail anymore, if the key does not exist or
1283 Bugfixes and a few tweaks described in the ChangeLog.
1287 Mostly a Bugfix release.
1289 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1290 timing with custom rules.
1294 We changed the internal rule storage format. Our large rule files took
1295 2 MB of RAM, with the change we are down to 99kB.
1297 If the device-node has been created with default name and no symlink or
1298 options are to remenber, it is not longer stored in the udevdb. HAL will
1299 need to be updated to work correctly with that change.
1301 To overrride optimization flags, OPTFLAGS may be used now.
1309 Major changes happened with this release. The goal is to take over the
1310 complete kernel-event handling and provide a more efficient way to dispatch
1311 kernel events. Replacing most of the current shell script logic and the
1312 kernel forked helper with a netlink-daemon and a rule-based event handling.
1314 o udevd listens to netlink events now. The first valid netlink event
1315 will make udevd ignore any message from udevsend that contains a
1316 SEQNUM, to avoid duplicate events. The forked events can be disabled
1318 echo "" > /proc/sys/kernel/hotplug
1319 For full support, the broken input-subsytem needs to be fixed, not to
1320 bypass the driver core.
1322 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1323 removed from udev itself and must be emulated by calling small
1324 helper binaries provided in the extras folder:
1325 make EXTRAS=extras/run_directory/
1326 will build udev_run_devd and udev_run_hotplugd, which can be called
1327 from a rule if needed:
1328 RUN+="/sbin/udev_run_hotplugd"
1329 The recommended way to handle this is to convert all the calls from
1330 the directories to explicit udev rules and get completely rid of the
1331 multiplexing. (To catch a ttyUSB event, you now no longer need to
1332 fork and exit 300 tty script instances you are not interested in, it
1333 is just one rule that matches exactly the device.)
1335 o udev handles now _all_ events not just events for class and block
1336 devices, this way it is possible to control the complete event
1337 behavior with udev rules. Especially useful for rules like:
1338 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1340 o As used in the modalias rule, udev supports now textual
1341 substitution placeholder along with the usual format chars. This
1342 needs to be documented, for now it's only visible in udev_rules_parse.c.
1344 o The rule keys support now more operations. This is documented in the
1345 man page. It is possible to add values to list-keys like the SYMLINK
1346 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1347 Also "final"-assignments are supported by using KEY:="value", which will
1348 prevent changing the key by any later rule.
1350 o kernel 2.6.12 has the "detached_state" attribute removed from
1351 sysfs, which was used to recognize sysfs population. We switched that
1352 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1353 Running this udev version on older kernels may cause a short delay for
1356 o To provide infrastructure for persistent device naming, the id programs:
1357 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1358 to export the probed data in environment key format:
1359 pim:~ # /sbin/ata_id --export /dev/hda
1360 ID_MODEL=HTS726060M9AT00
1361 ID_SERIAL=MRH401M4G6UM9B
1362 ID_REVISION=MH4OA6BA
1364 The following rules:
1365 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1366 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1369 kay@pim:~> tree /dev/disk
1372 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1373 | `-- IBM-Memory_Key -> ../../sda
1375 | |-- swap -> ../../hda1
1376 | |-- date -> ../../sda1
1377 | `-- home -> ../../hda3
1379 |-- 2E08712B0870F2E7 -> ../../hda3
1380 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1381 |-- E845-7A89 -> ../../sda1
1382 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1384 The IMPORT= operation will import these keys in the environment and make
1385 it available for later PROGRAM= and RUN= executed programs. The keys are
1386 also stored in the udevdb and can be queried from there with one of the
1389 o A few binaries are silently added to the repository, which can be used
1390 to replay kernel events from initramfs instead of using coldplug. udevd
1391 can be instructed now to queue-up events while the stored events from
1392 initramfs are filled into the udevd-queue. This code is still under
1393 development and there is no documentation now besides the code itself.
1394 The additional binaries get compiled, but are not installed by default.
1396 o There is also a temporary fix for a performance problem where too many
1397 events happen in parallel and every event needs to parse the rules.
1398 udev can now read precompiled rules stored on disk. This is likely to be
1399 replaced by a more elegant solution in a future udev version.
1403 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1404 Fix for libsysfs not to expect this file was added.
1408 All rules are applied now, but only the first matching rule with a NAME-key
1409 will be applied. All later rules with NAME-key are completely ignored. This
1410 way system supplied symlinks or permissions gets applied to user-defined
1414 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1415 to some rules, to keep the old behavior.
1417 The rules are read on "remove"-events too. That makes is possible to match
1418 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1419 instruct udev to ignore an event (OPTIONS="ignore_device").
1420 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1422 The new RUN-key supports rule-based execution of programs after device-node
1423 handling. This is meant as a general replacement for the dev.d/-directories
1424 to give fine grained control over the execution of programs.
1426 The %s{}-sysfs format char replacement values are searched at any of the
1427 devices in the device chain now, not only at the class-device.
1429 We support log priority levels now. The value udev_log in udev.conf is used
1430 to determine what is printed to syslog. This makes it possible to
1431 run a version with compiled-in debug messages in a production environment
1432 which is sometimes needed to find a bug.
1433 It is still possible to supress the inclusion of _any_ syslog usage with
1434 USE_LOG=false to create the smallest possible binaries if needed.
1435 The configured udev_log value can be overridden with the environment variable
1440 Possible use of a system-wide klibc:
1441 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1442 will link against an external klibc and our own version will be ignored.
1446 We support an unlimited count of symlinks now.
1448 If USE_STATIC=true is passed to a glibc build, we link statically and use
1449 a built-in userdb parser to resolve user and group names.
1451 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1452 we walk up the chain of physical devices to find a match.
1454 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1455 easy to skip certain attribute matches without composing rules with weird
1456 character class negations like:
1457 KERNEL="[!s][!c][!d]*"
1458 this can now be replaced with:
1460 The current simple '=' is still supported, and should work as it does today,
1461 but existing rules should be converted if possible, to be better readable.
1463 We have new ENV{}== key now, to match against a maximum of 5 environment
1466 udevstart is its own binary again, because we don't need co carry this araound
1467 with every forked event.