9 Properties set with ENV{.FOO}="bar" are marked private by starting the
10 name with a '.'. They will not be stored in the database, and not be
11 exported with the event.
13 Firmware files are looked up in:
14 /lib/firmware/updates/$(uname -r)
16 /lib/firmware/$(uname -r)
20 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
21 ata_id, instead of scsi_id, is the default tool now for ATA devices.
27 The configure options have changed because another library needs to be
28 installed in a different location. Instead of exec_prefix and udev_prefix,
29 libdir, rootlibdir and libexecdir are used. The Details are explained in
32 Event processes now get re-used after they handled an event. This reduces
33 the number of forks and the pressure on the CPU significantly, because
34 cloned event processes no longer cause page faults in the main daemon.
35 After the events have settled, a few worker processes stay around for
36 future events, all others get cleaned up.
38 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
39 Also inotify support is mandatory now to run udev.
41 The format of the queue exported by the udev damon has changed. There is
42 no longer a /dev/.udev/queue/ directory. The current event queue can be
43 accessed with udevadm settle and libudedv.
45 Libudev does not have the unstable API header anymore. From now on,
46 incompatible changes will be handled by bumping the library major version.
48 To build udev from the git tree gtk-doc is needed now. The tarballs will
49 build without it and contain the pre-built documentation. An online copy
51 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
53 The tools from the udev-extras repository have been merged into the main
54 udev repository. Some of the extras have larger external dependencies, and
55 they can be disabled with the configure switch --disable-extras.
61 The program vol_id and the library libvolume_id are removed from the
62 repository. Libvolume_id is merged with libblkid from the util-linux-ng
63 package. Persistent disk links for label and uuid depend on the
64 util-linux-ng version (2.15) of blkid now. Older versions of blkid
65 can not be used with udev.
67 Libudev allows to subscribe to udev events. To prevent unwanted messages
68 to be delivered, and waking up the subscribing process, a filter can be
69 installed, to drop messages inside a kernel socket filter. The filters
70 match on the <subsytem>:<devtype> properties of the device.
71 This is part of the ongoing effort to replace HAL, and switch current
72 users over to directly use libudev.
73 Libudev is still marked as experimental, and its interface might
74 eventually change if needed, but no major changes of the currently exported
75 interface are expected anymore, and a first stable release should happen
78 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
79 is not supported since while and udevd will log an error message at
80 startup. It should still be able to boot-up, but advanced rules and system
81 services which depend on the information not available in the old sysfs
82 format will fail to work correctly.
84 DVB device naming is supplied by the kernel now. In case older kernels
85 need to be supported, the old shell script should be added to a compat
92 The processed udev events get send back to the netlink socket. Libudev
93 provides access to these events. This is work-in-progress, to replace
94 the DeviceKit daemon functionality directly with libudev. There are
95 upcoming kernel changes to allow non-root users to subcribe to these
102 "udevadm settle" now optionally accepts a range of events to wait for,
103 instead of waiting for "all" events.
109 The installed watch for block device metadata changes is now removed
110 during event hadling, because some (broken) tools may be called from udev
111 rules and (wrongly) open the device with write access. After the finished
112 event handling the watch is restored.
118 Device nodes can be watched for changes with inotify with OPTIONS="watch".
119 If closed after being opened for writing, a "change" uevent will occur.
120 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
126 The udevadm test command has no longer a --force option, nodes and symlinks
127 are always updated with a test run now.
129 The udevd daemon can be started with --resolve-names=never to avoid all user
130 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
131 lookup user and groups every time events are handled.
137 We are currently merging the Ubuntu rules in the udev default rules,
138 and get one step closer to provide a common Linux /dev setup, regarding
139 device names, symlinks, and default device permissions. On udev startup,
140 we now expect the following groups to be resolvable to their ids with
142 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
143 LDAP setups need to make sure, that these groups are always resolvable at
144 bootup, with only the rootfs mounted, and without network access available.
146 Some systems may need to add some new, currently not used groups, or need
147 to add some users to new groups, but the cost of this change is minimal,
148 compared to the pain the current, rather random, differences between the
149 various distributions cause for upstream projects and third-party vendors.
151 In general, "normal" users who log into a machine should never be a member
152 of any such group, but the device-access should be managed by dynamic ACLs,
153 which get added and removed for the specific users on login/logout and
154 session activity/inactivity. These groups are only provided for custom setups,
155 and mainly system services, to allow proper privilege separation.
156 A video-streaming daemon uid would be a member of "audio" and "video", to get
157 access to the sound and video devices, but no "normal" user should ever belong
158 to the "audio" group, because he could listen to the built-in microphone with
159 any ssh-session established from the other side of the world.
161 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
162 which do not depend on the kernel device name. As usual, unique
163 devices - only a single one per product connected, or a real
164 USB serial number in the device - are always found with the same
165 name in the by-id/ directory.
166 Completely identical devices may overwrite their names in by-id/
167 and can only be found reliably in the by-path/ directory. Devices
168 specified by by-path/ must not change their connection, like the
169 USB port number they are plugged in, to keep their name.
171 To support some advanced features, Linux 2.6.22 is the oldest supported
172 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
173 supported. Older kernels should still work, and devices nodes should be
174 reliably created, but some rules and libudev will not work correctly because
175 the old kernels do not provide the expected information or interfaces.
181 Fix for a possible segfault while swapping network interface names in udev
188 The group "video" is part of the default rules now.
192 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
193 block devices in some cases. No common distro uses this option anymore,
194 and we do not get enough testing for this and recent udev versions. If
195 this option is not needed to run some old distro with a new kernel,
196 it should be disabled in the kernel config.
198 Bugfix for the $links substitution variable, which may crash if no links
199 are created. This should not happen in usual setups because we always
200 create /dev/{block,char}/ links.
202 The strings of the parsed rules, which are kept in memory, no longer
203 contain duplicate entries, or duplicate tails of strings. This, and the
204 new rules parsing/matching code reduces the total in-memory size of
205 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
208 The export of DEVTYPE=disk/partition got removed from the default
209 rules. This value is available from the kernel. The pnp shell script
210 modprobe hack is removed from the default rules. ACPI devices have _proper_
211 modalias support and take care of the same functionality.
212 Installations which support old kernels, but install current default
213 udev rules may want to add that to the compat rules file.
215 Libvolume_id now always probes for all known filesystems, and does not
216 stop at the first match. Some filesystems are marked as "exclusive probe",
217 and if any other filesytem type matches at the same time, libvolume_id
218 will, by default, not return any probing result. This is intended to prevent
219 mis-detection with conflicting left-over signatures found from earlier
220 file system formats. That way, we no longer depend on the probe-order
221 in case of multiple competing signatures. In some setups the kernel allows
222 to mount a volume with just the old filesystem signature still in place.
223 This may damage the new filesystem and cause data-loss, just by mounting
224 it. Because volume_id can not decide which one the correct signature is,
225 the wrong signatures need to be removed manually from the volume, or the
226 volume needs to be reformatted, to enable filesystem detection and possible
231 Fix segfault if compiled without optimization and dbg() does not get
232 compiled out and uses variables which are not available.
236 Bugfixes. (And maybe new bugs. :))
238 The rule matching engine got converted from a rule list to a token
239 array which reduced the in-memory rules representation of a full
240 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
241 Limits like 5 ENV and ATTR matches, and one single instance for most
242 other keys per rule are gone.
244 The NAME assignment is no longer special cased. If later rules assign
245 a NAME value again, the former value will be overwritten. As usual
246 for most other keys, the NAME value can be protected by doing a final
247 assignment with NAME:="<value>".
249 All udev code now uses libudev, which is also exported. The library
250 is still under development, marked as experimental, and its interface
251 may change as long as the DeviceKit integration is not finished.
253 Many thanks to Alan Jenkins for his continuous help, and finding and
254 optimizing some of the computing expensive parts.
260 Kernel devices and device nodes are connected now by reverse indizes in
261 /sys and /dev. A device number retrieved by a stat() or similar, the
262 kernel device directory can be found by looking up:
263 /sys/dev/{block,char}/<maj>:<min>
264 and the device node of the same device by looking up:
265 /dev/{block,char}/<maj>:<min>
269 Fix recently introduced bug, which caused a compilation without large
270 file support, where vol_id does not recognize raid signatures at the end
273 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
274 Seems some kernel versions prevent the creation of the ieee-* links,
275 so people used the scsi-* link which disappeared now.
277 More libudev work. Almost all udevadm functionality comes from libudev
280 udevadm trigger has a new option --type, which allows to trigger events
281 for "devices", for "subsystems", or "failed" devices. The old option
282 --retry-failed" still works, but is no longer mentioned in the man page.
288 The udevadm info --device-id-of-file= output has changed to use
289 the obvious format. Possible current users should use the --export
290 option which is not affected.
292 The old udev commands symlinks to udevadm are not installed, if
293 these symlinks are used, a warning is printed.
299 Optical drive's media is no longer probed for raid signatures,
300 reading the end of the device causes some devices to malfunction.
301 Also the offset of the last session found is used now to probe
304 The volume_id library got a major version number update to 1,
305 some deprecated functions are removed.
307 A shared library "libudev" gets installed now to provide access
308 to udev device information. DeviceKit, the successor of HAL, will
309 need this library to access the udev database and search sysfs for
311 The library is currently in an experimental state, also the API is
312 expected to change, as long as the DeviceKit integration is not
317 We use ./configure now. See INSTALL for details. Current
320 "/usr" - prefix for man pages, include files
322 "" - the root filesystem, prefix for libs and binaries
326 "lib" - directory name for libraries, not a path name
327 multilib 64bit systems may use "lib64" instead of "lib"
329 compile-in verbose debug messages
331 disable all logging and compile-out all log strings
333 link against SELInux libraries, to set the expected context
336 In the default rules, the group "disk" gets permissions 0660 instead
337 of 0640. One small step closer to unify distro rules. Some day, all
338 distros hopefully end up with the same set of rules.
340 No symlinks to udevadm are installed anymore, if they are still needed,
341 they should be provided by the package.
347 Default udev rules, which are not supposed to be edited by the user, should
348 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
349 the udev package and will be replaced with an update. Udev will pick up rule
351 /lib/udev/rules.d/ - default installed rules
352 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
353 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
354 It does not matter in which directory a rule file lives, all files are sorted
357 To help creating /dev/root, we have now:
358 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
361 In case the current --device-id-of-file is already used, please switch to
362 the --export format version, it saves the output parsing and the old
363 format will be changed to use ':' as a separator, like the format in the
368 Fix cdrom_id to properly recognize blank media.
374 Tape drive id-data is queried from /dev/bsg/* instead of the tape
375 nodes. This avoids rewinding tapes on open().
381 The symlinks udevcontrol and udevtrigger are no longer installed by
384 The scsi_id program does not depend on sysfs anymore. It can speak
385 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
386 data, which should solve some old problems with tape devices, where
387 we better do not open all tape device nodes to identify the device.
393 The cdrom_id program is replaced by an advanced version, which can
394 detect most common device types, and also properties of the inserted
395 media. This is part of moving some basic functionality from HAL into
396 udev (and the kernel).
402 The last WAIT_FOR_SYSFS rule is removed from the default rules.
404 The symlinks to udevadm for the debugging tools: udevmonitor and
405 udevtest are no longer created.
407 The symlinks to the udevadm man page for the old tool names are
410 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
411 should be prefixed with '@' to indicate that the path is not a
422 Udevstart is removed from the tree, it did not get installed for
423 a long time now, and is long replaced by trigger and settle.
429 All udev tools are merged into a single binary called udevadm.
430 The old names of the tools are built-in commands in udevadm now.
431 Symlinks to udevadm, with the names of the old tools, provide
432 the same functionality as the standalone tools. There is also
433 only a single udevadm.8 man page left for all tools.
435 Tools like mkinitramfs should be checked, if they need to include
436 udevadm in the list of files.
446 The etc/udev/rules.d/ directory now contains a default set of basic
447 udev rules. This initial version is the result of a rules file merge
448 of Fedora and openSUSE. For these both distros only a few specific
449 rules are left in their own file, named after the distro. Rules which
450 are optionally installed, because they are only valid for a specific
451 architecture, or rules for subsystems which are not always used are
452 in etc/udev/packages/.
458 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
459 actions by dynamically created rules.
461 SYMLINK=="<value>" matches agains the entries in the list of
462 currently defined symlinks. The links are not created in the
463 filesystem at that point in time, but the values can be matched.
465 RUN{ignore_error}+="<program>" will ignore any exit code from the
466 program and not record as a failed event.
472 Final merge of patches/features from the Ubuntu package.
478 Control characters in filesystem label strings are no longer silenty
479 removed, but hex-encoded, to be able to uniquely identify the device
480 by its symlink in /dev/disk/by-label/.
481 If libvolume_id is used by mount(8), LABEL= will work as expected,
482 if slashes or other characters are used in the label string.
484 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
485 can be specified now. The TEST key accepts an optional mode mask
486 TEST{0100}=="<is executable file>".
488 Scsi_id now supports a mode without expecting scsi-specific sysfs
489 entries to allow the extraction of cciss-device persistent properties.
495 In the future, we may see uuid's which are just simple character
496 strings (see the DDF Raid Specification). For that reason vol_id now
497 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
498 the creation of symlinks, the *_SAFE values ensure, that no control
499 or whitespace characters are used in the filename.
501 Possible users of libvolume_id, please use the volume_id_get_* functions.
502 The public struct will go away in a future release of the library.
508 Removal of useless extras/eventrecorder.sh.
518 The directory multiplexer for dev.d/ and hotplug.d are finally removed
519 from the udev package.
525 Symlinks can have priorities now, the priority is assigned to the device
526 and specified with OPTIONS="link_priority=100". Devices with higher
527 priorities overwrite the symlinks of devices with lower priorities.
528 If the device that currently owns the link, goes away, the symlink
529 will be removed, and recreated, pointing to the next device with the
530 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
531 more reliable, if multiple devices contain the same metadata and overwrite
534 The dasd_id program is removed from the udev tree, and dasdinfo, with the
535 needed rules, are part of the s390-tools now.
537 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
538 we may get the scsi sysfs mess fixed some day, and this will only catch
539 the devices we are looking for.
541 USB serial numbers for storage devices have the target:lun now appended,
542 to make it possibble to distinguish broken multi-lun devices with all
543 the same SCSI identifiers.
545 Note: The extra "run_directory" which searches and executes stuff in
546 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
547 with the next release. Make sure, that you don't use it anymore, or
548 provides your own implementation of that inefficient stuff.
549 We are tired of reports about a "slow udev", because these directories
550 contain stuff, that runs with _every_ event, instead of using rules,
551 that run programs only for the matching events.
561 DRIVER== will match only for devices that actually have a real
562 driver. DRIVERS== must be used, if parent devices should be
563 included in the match.
565 Libvolume_id's "linux_raid" detection needed another fix.
573 Add additional check to volume_id detection of via_raid, cause
574 some company decided to put a matching pattern all over the empty
575 storage area of their music players.
579 Fix path_id for SAS devices.
583 The udev daemon can be started with --debug-trace now, which will
584 execute all events serialized to get a chance to catch a possible
585 action that crashes the box.
587 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
588 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
589 are excluded from the warning. Referencing parent attributes directly
590 may break when something in the kernel driver model changes. Udev will
591 just find the attribute by walking up the parent chain.
593 Udevtrigger now sorts the list of devices depending on the device
594 dependency, so a "usb" device is triggered after the parent "pci"
599 Revert persistent-storage ata-serial '_' '-' replacement.
605 Udevtrigger can now filter the list of devices to be triggered. Matches
606 for subsystems or sysfs attributes can be specified.
608 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
609 zero-sized files to avoid pointing to /sys and confuse broken tools which
610 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
613 The rules and scripts to create udev rules for persistent network
614 devices and optical drives are in the extras/rules_generator directory
615 now. If you use something similar, please consider replacing your own
616 version with this, to share the support effort. The rule_generator
617 installs its own rules into /etc/udev/rules.d.
619 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
620 the rule_generator depends on cdrom_id to be called in an earlier rule.
626 Renaming of some key names (the old names still work):
627 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
628 (The behavior of the key DRIVER will change soon in one of the next
629 releases, to match only the event device, please switch to DRIVERS
630 instead. If DRIVER is used, it will behave like DRIVERS, but an error
632 With the new key names, we have a more consistent and simpler scheme.
633 We can match the properties of the event device only, with: KERNEL,
634 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
635 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
636 longer mentioned in the man page and should be switched in the rule
639 ATTR{file}="value" can be used now, to write to a sysfs file of the
640 event device. Instead of:
641 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
643 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
645 All the PHYSDEV* keys are deprecated and will be removed from a
647 PHYDEVPATH - is the path of a parent device and should not be
649 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
650 matched with SUBSYSTEMS==
651 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
652 Newer kernels will have DRIVER in the environment,
653 for older kernels udev puts in. Class device will
654 no longer carry this property of a parent and
655 DRIVERS== can be used to match such a parent value.
656 Note that ENV{DRIVER} is only available for a few bus devices, where
657 the driver is already bound at device event time. On coldplug, the
658 events for a lot devices are already bound to a driver, and they will have
659 that value set. But on hotplug, at the time the kernel creates the device,
660 it can't know what driver may claim the device after that, therefore
661 in most cases it will be empty.
663 Failed events should now be re-triggered with:
664 udevtrigger --retry-failed.
665 Please switch to this command, so we keep the details of the /dev/.udev/failed/
666 files private to the udev tools. We may need to switch the current symlink
667 target, cause some obviously broken tools try to scan all files in /dev
668 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
669 million times. This takes ages on slow boxes.
671 The udevinfo attribute walk (-a) now works with giving a device node
672 name (-n) instead of a devpath (-p). The query now always works, also when
673 no database file was created by udev.
675 The built-in /etc/passwd /etc/group parser is removed, we always depend on
676 getpwnam() and getgrnam() now. One of the next releases will depend on
677 fnmatch() and may use getopt_long().
681 Bugfixes and small improvements.
685 Fix path_id for recent kernels.
691 Added support for swapping network interface names, by temporarily
692 renaming the device and wait for the target name to become free.
696 The built-in MODALIAS key and substitution is removed.
700 The binary firmware helper is replaced by the usual simple
701 shell script. Udevsend is removed from the tree.
709 Some more keys require the correct use of '==' and '=' depending
710 on the kind of operation beeing an assignment or a match. Rules
711 with invalid operations are skipped and logged to syslog. Please
712 test with udevtest if the parsing of your rules throws errors and
713 fix possibly broken rules.
717 Provide "udevsettle" to wait for all current udev events to finish.
718 It also watches the current kernel netlink queue by comparing the
719 even sequence number to make sure that there are no current pending
720 events that have not already arrived in the daemon.
724 Fix rule to skip persistent rules for removable IDE devices, which
725 also skipped optical IDE drives.
727 All *_id program are installed in /lib/udev/ by default now.
729 No binary is stripped anymore as this should be done in the
730 packaging process and not at build time.
732 libvolume_id is provided as a shared library now and vol_id is
733 linked against it. Also one of the next HAL versions will require
734 this library, and the HAL build process will also require the
735 header file to be installed. The copy of the same code in HAL will
736 be removed to have only a single copy left on the system.
740 Add persistent links for SCSI tapes. The rules file is renamed
741 to 60-persistent-storage.rules.
743 Create persistent path for usb devices. Can be used for all sorts
744 of devices that can't be distinguished by other properties like
745 multiple identical keyboards and mice connected to the same box.
747 Provide "udevtrigger" program to request events on coldplug. The
748 shell script is much too slow with thousends of devices.
752 Fix persistent disk rules to exclude removable IDE drives.
754 Warn if %e, $modalias or MODALIAS is used.
758 Fix queue export, which wasn't correct for subsequent add/remove
759 events for the same device.
763 Fix cramfs detection on big endian.
765 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
770 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
771 attributes were only checked at the parent device that matched the
772 by BUS requested subsystem. Fix it to also look at the device we
773 received the event for.
775 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
780 Fix a bug where NAME="" would prevent RUN from beeing executed.
782 RUN="/bin/program" does not longer automatically add the subsystem
783 as the first parameter. This is from the days of /sbin/hotplug
784 which is dead now and it's just confusing to need to add a space at
785 the end of the program name to prevent this.
786 If you use rules that need the subsystem as the first parameter,
787 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
788 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
792 The udev man page has moved to udev(7) as it does not describe a command
793 anymore. The programs udev, udevstart and udevsend are no longer installed
794 by default and must be copied manually, if they should be installed or
795 included in a package.
797 Fix a bug where "ignore_device" could run earlier collected RUN keys before
798 the ignore rule was applied.
800 More preparation for future sysfs changes. usb_id and scsi_id no longer
801 depend on a magic order of devices in the /devices chain. Specific devices
802 should be requested by their subsytem.
804 This will always find the scsi parent device without depending on a specific
806 dev = sysfs_device_get(devpath);
807 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
809 The "device" link in the current sysfs layout will be automatically
810 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
811 parent in the devpath. If a device is requested by it's symlink, like all
812 class devices in the new sysfs layout will look like, it gets automatically
813 resolved and substituted with the real devpath and not the symlink path.
816 A similar logic must be applied to _all_ sysfs users, including
817 scripts, that search along parent devices in sysfs. The explicit use of
818 the "device" link must be avoided. With the future sysfs layout all
819 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
820 back to the "class" or the "bus". The layout of the parent devices in
821 /devices is not necessarily expected to be stable across kernel releases and
822 searching for parents by their subsystem should make sysfs users tolerant
823 for changed parent chains.
827 Prepare udev to work with the experimental kernel patch, that moves
828 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
830 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
831 moving the class devices to /sys/devices.
833 Thanks again to Marco for help finding a hopefully nice compromise
834 to make %b simpler and working again.
838 Complete removal of libsysfs, replaced by simple helper functions
839 which are much simpler and a bit faster. The udev daemon operatesentirely
840 on event parameters and does not use sysfs for simple rules anymore.
841 Please report any new bugs/problems, that may be caused by this big
842 change. They will be fixed immediately.
844 The enumeration format character '%e' is deprecated and will be
845 removed sometimes from a future udev version. It never worked correctly
846 outside of udevstart, so we can't use it with the new parallel
847 coldplug. A simple enumeration is as useless as the devfs naming
848 scheme, just get rid of both if you still use it.
850 MODALIAS and $modalias is not needed and will be removed from one of
851 the next udev versions, replace it in all rules with ENV{MODALIAS} or
852 the sysfs "modalias" value.
854 Thanks a lot to Marco for all his help on finding and fixing bugs.
858 Let scsi_id request libata drive serial numbers from page 0x80.
860 Renamed etc/udev/persistent.rules to persistent-disk.rules and
861 added /dev/disk/by-name/* for device mapper device names.
863 Removed %e from the man page. It never worked reliably outside
864 of udevstart and udevstart is no longer recommended to use.
868 Symlinks are now exported to the event environment. Hopefully it's no
869 longer needed to run udevinfo from an event process, like it was
870 mentioned on the hotplug list:
871 UDEV [1134776873.702967] add@/block/sdb
874 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
878 Fix a problem if udevsend is used as the hotplug handler and tries to use
879 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
880 and this kind of problems will hopefully go away soon.
884 All built-in logic to work around bad sysfs timing is removed with this
885 version. The need to wait for sysfs files is almost fixed with a kernel
886 version that doesn't work with this udev version anyway. Until we fix
887 the timing of the "bus" link creation, the former integrated logic should
888 be emulated by a rule placed before all other rules:
889 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
891 The option "udev_db" does no longer exist. All udev state will be in
892 /$udev_root/.udev/ now, there is no longer an option to set this
894 If the init script or something else used this value, just depend on
895 this hardcoded path. But remember _all_content_ of this directory is
896 still private to udev and can change at any time.
898 Default location for rule sripts and helper programs is now: /lib/udev/.
899 Everything that is not useful on the commandline should go into this
900 directory. Some of the helpers in the extras folder are installed there
901 now. The rules need to be changed, to find the helpers there.
903 Also /lib/udev/devices is recommended as a directory where packages or
904 the user can place real device nodes, which get copied over to /dev at
905 every boot. This should replace the various solutions with custom config
908 Udevsend does no longer start the udev daemon. This must be done with
909 the init script that prepares /dev on tmpfs and creates the initial nodes,
910 before starting the daemon.
914 Silent a too verbose error logging for the old hotplug.d/ dev.d/
917 The copy of klibc is removed. A systemwide installed version of klibc
918 should be used to build a klibc udev now.
922 NAME="" will not create any nodes, but execute RUN keys. To completely
923 ignore an event the OPTION "ignore_device" should be used.
925 After removal of the reorder queue, events with a TIMEOUT can be executed
926 without any queuing now.
930 Fixed bug in udevd, if inotify is not available. We depend on netlink
931 uevents now, kernels without that event source will not work with that
932 version of udev anymore.
936 The rule parsing happens now in the daemon once at startup, all udev
937 event processes inherit the already parsed rules from the daemon.
938 It is shipped with SUSE10.0 and reduces heavily the system load at
939 startup. The option to save precompiled rules and let the udev process
940 pick the them up is removed, as it's no longer needed.
942 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
943 device. Libsysfs is changed to "translate" the requested link into the
944 real device path, as it would happen with the hotplug event. Otherwise
945 device removal and the udev database will not work.
947 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
950 A few improvements for vol_id, the filesytem probing code.
954 Fix a stupid typo in extras/run_directory for "make install".
956 scsi_id creates the temporary devnode now in /dev for usage with a
957 non-writable /tmp directory.
959 The uevent kernel socket buffer can carry app. 50.000 events now,
960 let's see who can break this again. :)
962 The upcoming kernel will have a new input driver core integration.
963 Some class devices are now symlinks to the real device. libsysfs
964 needs a fix for this to work correctly. Udevstart of older udev
965 versions will _not_ create these devices!
969 Fix a 'install' target in the Makefile, that prevents EXTRAS from
974 A bunch of mostly trivial bugfixes. From now on no node name or
975 symlink name can contain any character than plain whitelisted ascii
976 characters or validated utf8 byte-streams. This is needed for the
977 /dev/disk/by-label/* links, because we import untrusted data and
978 export it to the filesystem.
982 More bugfixes. If udevd was started from the kernel, we don't
983 have stdin/stdout/stderr, which broke the forked tools in some
988 Bugfix. udevstart event ordering was broken for a long time.
989 The new run_program() uncovered it, because /dev/null was not
990 available while we try to run external programs.
991 Now udevstart should create it before we run anything.
995 Minor bugfixes and some distro rules updates. If you don't have the
996 persistent disk rules in /dev/disk/by-*/* on your distro, just
997 grab it from here. :)
1001 We can use socket communication now to pass events from udev to
1003 RUN+="socket:/org/freedesktop/hal/udev_event"
1004 will pass the whole udev event to the HAL daemon without the need
1005 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1009 Mostly bugfixes and see ChangeLog.
1011 The test for the existence of an environment value should be
1013 ENV{KEY}=="*" to ENV{KEY}=="?*"
1014 because "*" will not fail anymore, if the key does not exist or
1019 Bugfixes and a few tweaks described in the ChangeLog.
1023 Mostly a Bugfix release.
1025 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1026 timing with custom rules.
1030 We changed the internal rule storage format. Our large rule files took
1031 2 MB of RAM, with the change we are down to 99kB.
1033 If the device-node has been created with default name and no symlink or
1034 options are to remenber, it is not longer stored in the udevdb. HAL will
1035 need to be updated to work correctly with that change.
1037 To overrride optimization flags, OPTFLAGS may be used now.
1045 Major changes happened with this release. The goal is to take over the
1046 complete kernel-event handling and provide a more efficient way to dispatch
1047 kernel events. Replacing most of the current shell script logic and the
1048 kernel forked helper with a netlink-daemon and a rule-based event handling.
1050 o udevd listens to netlink events now. The first valid netlink event
1051 will make udevd ignore any message from udevsend that contains a
1052 SEQNUM, to avoid duplicate events. The forked events can be disabled
1054 echo "" > /proc/sys/kernel/hotplug
1055 For full support, the broken input-subsytem needs to be fixed, not to
1056 bypass the driver core.
1058 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1059 removed from udev itself and must be emulated by calling small
1060 helper binaries provided in the extras folder:
1061 make EXTRAS=extras/run_directory/
1062 will build udev_run_devd and udev_run_hotplugd, which can be called
1063 from a rule if needed:
1064 RUN+="/sbin/udev_run_hotplugd"
1065 The recommended way to handle this is to convert all the calls from
1066 the directories to explicit udev rules and get completely rid of the
1067 multiplexing. (To catch a ttyUSB event, you now no longer need to
1068 fork and exit 300 tty script instances you are not interested in, it
1069 is just one rule that matches exactly the device.)
1071 o udev handles now _all_ events not just events for class and block
1072 devices, this way it is possible to control the complete event
1073 behavior with udev rules. Especially useful for rules like:
1074 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1076 o As used in the modalias rule, udev supports now textual
1077 substitution placeholder along with the usual format chars. This
1078 needs to be documented, for now it's only visible in udev_rules_parse.c.
1080 o The rule keys support now more operations. This is documented in the
1081 man page. It is possible to add values to list-keys like the SYMLINK
1082 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1083 Also "final"-assignments are supported by using KEY:="value", which will
1084 prevent changing the key by any later rule.
1086 o kernel 2.6.12 has the "detached_state" attribute removed from
1087 sysfs, which was used to recognize sysfs population. We switched that
1088 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1089 Running this udev version on older kernels may cause a short delay for
1092 o To provide infrastructure for persistent device naming, the id programs:
1093 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1094 to export the probed data in environment key format:
1095 pim:~ # /sbin/ata_id --export /dev/hda
1096 ID_MODEL=HTS726060M9AT00
1097 ID_SERIAL=MRH401M4G6UM9B
1098 ID_REVISION=MH4OA6BA
1100 The following rules:
1101 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1102 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1105 kay@pim:~> tree /dev/disk
1108 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1109 | `-- IBM-Memory_Key -> ../../sda
1111 | |-- swap -> ../../hda1
1112 | |-- date -> ../../sda1
1113 | `-- home -> ../../hda3
1115 |-- 2E08712B0870F2E7 -> ../../hda3
1116 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1117 |-- E845-7A89 -> ../../sda1
1118 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1120 The IMPORT= operation will import these keys in the environment and make
1121 it available for later PROGRAM= and RUN= executed programs. The keys are
1122 also stored in the udevdb and can be queried from there with one of the
1125 o A few binaries are silently added to the repository, which can be used
1126 to replay kernel events from initramfs instead of using coldplug. udevd
1127 can be instructed now to queue-up events while the stored events from
1128 initramfs are filled into the udevd-queue. This code is still under
1129 development and there is no documentation now besides the code itself.
1130 The additional binaries get compiled, but are not installed by default.
1132 o There is also a temporary fix for a performance problem where too many
1133 events happen in parallel and every event needs to parse the rules.
1134 udev can now read precompiled rules stored on disk. This is likely to be
1135 replaced by a more elegant solution in a future udev version.
1139 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1140 Fix for libsysfs not to expect this file was added.
1144 All rules are applied now, but only the first matching rule with a NAME-key
1145 will be applied. All later rules with NAME-key are completely ignored. This
1146 way system supplied symlinks or permissions gets applied to user-defined
1150 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1151 to some rules, to keep the old behavior.
1153 The rules are read on "remove"-events too. That makes is possible to match
1154 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1155 instruct udev to ignore an event (OPTIONS="ignore_device").
1156 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1158 The new RUN-key supports rule-based execution of programs after device-node
1159 handling. This is meant as a general replacement for the dev.d/-directories
1160 to give fine grained control over the execution of programs.
1162 The %s{}-sysfs format char replacement values are searched at any of the
1163 devices in the device chain now, not only at the class-device.
1165 We support log priority levels now. The value udev_log in udev.conf is used
1166 to determine what is printed to syslog. This makes it possible to
1167 run a version with compiled-in debug messages in a production environment
1168 which is sometimes needed to find a bug.
1169 It is still possible to supress the inclusion of _any_ syslog usage with
1170 USE_LOG=false to create the smallest possible binaries if needed.
1171 The configured udev_log value can be overridden with the environment variable
1176 Possible use of a system-wide klibc:
1177 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1178 will link against an external klibc and our own version will be ignored.
1182 We support an unlimited count of symlinks now.
1184 If USE_STATIC=true is passed to a glibc build, we link statically and use
1185 a built-in userdb parser to resolve user and group names.
1187 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1188 we walk up the chain of physical devices to find a match.
1190 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1191 easy to skip certain attribute matches without composing rules with weird
1192 character class negations like:
1193 KERNEL="[!s][!c][!d]*"
1194 this can now be replaced with:
1196 The current simple '=' is still supported, and should work as it does today,
1197 but existing rules should be converted if possible, to be better readable.
1199 We have new ENV{}== key now, to match against a maximum of 5 environment
1202 udevstart is its own binary again, because we don't need co carry this araound
1203 with every forked event.