5 Event processes now get re-used after they handled an event. This reduces
6 the number of forks and the pressure on the CPU significantly, because
7 cloned event processes no longer cause page faults in the main daemon.
8 After the events have settled, a few worker processes stay around for
9 future events, all others get cleaned up.
11 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
12 Also inotify support is mandatory now to run udev.
14 The format of the queue exported by the udev damon has changed. There is
15 no longer a /dev/.udev/queue/ directory. The current event queue can be
16 accessed with udevadm settle and libudedv.
18 Libudev does not have the unstable API header anymore. From now on,
19 incompatible changes will be handled by bumping the library major version.
21 To build udev from the git tree gtk-doc is needed now. The tarballs will
22 build without it and contain the pre-built documentation. An online copy
24 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
30 The program vol_id and the library libvolume_id are removed from the
31 repository. Libvolume_id is merged with libblkid from the util-linux-ng
32 package. Persistent disk links for label and uuid depend on the
33 util-linux-ng version (2.15) of blkid now. Older versions of blkid
34 can not be used with udev.
36 Libudev allows to subscribe to udev events. To prevent unwanted messages
37 to be delivered, and waking up the subscribing process, a filter can be
38 installed, to drop messages inside a kernel socket filter. The filters
39 match on the <subsytem>:<devtype> properties of the device.
40 This is part of the ongoing effort to replace HAL, and switch current
41 users over to directly use libudev.
42 Libudev is still marked as experimental, and its interface might
43 eventually change if needed, but no major changes of the currently exported
44 interface are expected anymore, and a first stable release should happen
47 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
48 is not supported since while and udevd will log an error message at
49 startup. It should still be able to boot-up, but advanced rules and system
50 services which depend on the information not available in the old sysfs
51 format will fail to work correctly.
53 DVB device naming is supplied by the kernel now. In case older kernels
54 need to be supported, the old shell script should be added to a compat
61 The processed udev events get send back to the netlink socket. Libudev
62 provides access to these events. This is work-in-progress, to replace
63 the DeviceKit daemon functionality directly with libudev. There are
64 upcoming kernel changes to allow non-root users to subcribe to these
71 "udevadm settle" now optionally accepts a range of events to wait for,
72 instead of waiting for "all" events.
78 The installed watch for block device metadata changes is now removed
79 during event hadling, because some (broken) tools may be called from udev
80 rules and (wrongly) open the device with write access. After the finished
81 event handling the watch is restored.
87 Device nodes can be watched for changes with inotify with OPTIONS="watch".
88 If closed after being opened for writing, a "change" uevent will occur.
89 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
95 The udevadm test command has no longer a --force option, nodes and symlinks
96 are always updated with a test run now.
98 The udevd daemon can be started with --resolve-names=never to avoid all user
99 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
100 lookup user and groups every time events are handled.
106 We are currently merging the Ubuntu rules in the udev default rules,
107 and get one step closer to provide a common Linux /dev setup, regarding
108 device names, symlinks, and default device permissions. On udev startup,
109 we now expect the following groups to be resolvable to their ids with
111 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
112 LDAP setups need to make sure, that these groups are always resolvable at
113 bootup, with only the rootfs mounted, and without network access available.
115 Some systems may need to add some new, currently not used groups, or need
116 to add some users to new groups, but the cost of this change is minimal,
117 compared to the pain the current, rather random, differences between the
118 various distributions cause for upstream projects and third-party vendors.
120 In general, "normal" users who log into a machine should never be a member
121 of any such group, but the device-access should be managed by dynamic ACLs,
122 which get added and removed for the specific users on login/logout and
123 session activity/inactivity. These groups are only provided for custom setups,
124 and mainly system services, to allow proper privilege separation.
125 A video-streaming daemon uid would be a member of "audio" and "video", to get
126 access to the sound and video devices, but no "normal" user should ever belong
127 to the "audio" group, because he could listen to the built-in microphone with
128 any ssh-session established from the other side of the world.
130 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
131 which do not depend on the kernel device name. As usual, unique
132 devices - only a single one per product connected, or a real
133 USB serial number in the device - are always found with the same
134 name in the by-id/ directory.
135 Completely identical devices may overwrite their names in by-id/
136 and can only be found reliably in the by-path/ directory. Devices
137 specified by by-path/ must not change their connection, like the
138 USB port number they are plugged in, to keep their name.
140 To support some advanced features, Linux 2.6.22 is the oldest supported
141 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
142 supported. Older kernels should still work, and devices nodes should be
143 reliably created, but some rules and libudev will not work correctly because
144 the old kernels do not provide the expected information or interfaces.
150 Fix for a possible segfault while swapping network interface names in udev
157 The group "video" is part of the default rules now.
161 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
162 block devices in some cases. No common distro uses this option anymore,
163 and we do not get enough testing for this and recent udev versions. If
164 this option is not needed to run some old distro with a new kernel,
165 it should be disabled in the kernel config.
167 Bugfix for the $links substitution variable, which may crash if no links
168 are created. This should not happen in usual setups because we always
169 create /dev/{block,char}/ links.
171 The strings of the parsed rules, which are kept in memory, no longer
172 contain duplicate entries, or duplicate tails of strings. This, and the
173 new rules parsing/matching code reduces the total in-memory size of
174 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
177 The export of DEVTYPE=disk/partition got removed from the default
178 rules. This value is available from the kernel. The pnp shell script
179 modprobe hack is removed from the default rules. ACPI devices have _proper_
180 modalias support and take care of the same functionality.
181 Installations which support old kernels, but install current default
182 udev rules may want to add that to the compat rules file.
184 Libvolume_id now always probes for all known filesystems, and does not
185 stop at the first match. Some filesystems are marked as "exclusive probe",
186 and if any other filesytem type matches at the same time, libvolume_id
187 will, by default, not return any probing result. This is intended to prevent
188 mis-detection with conflicting left-over signatures found from earlier
189 file system formats. That way, we no longer depend on the probe-order
190 in case of multiple competing signatures. In some setups the kernel allows
191 to mount a volume with just the old filesystem signature still in place.
192 This may damage the new filesystem and cause data-loss, just by mounting
193 it. Because volume_id can not decide which one the correct signature is,
194 the wrong signatures need to be removed manually from the volume, or the
195 volume needs to be reformatted, to enable filesystem detection and possible
200 Fix segfault if compiled without optimization and dbg() does not get
201 compiled out and uses variables which are not available.
205 Bugfixes. (And maybe new bugs. :))
207 The rule matching engine got converted from a rule list to a token
208 array which reduced the in-memory rules representation of a full
209 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
210 Limits like 5 ENV and ATTR matches, and one single instance for most
211 other keys per rule are gone.
213 The NAME assignment is no longer special cased. If later rules assign
214 a NAME value again, the former value will be overwritten. As usual
215 for most other keys, the NAME value can be protected by doing a final
216 assignment with NAME:="<value>".
218 All udev code now uses libudev, which is also exported. The library
219 is still under development, marked as experimental, and its interface
220 may change as long as the DeviceKit integration is not finished.
222 Many thanks to Alan Jenkins for his continuous help, and finding and
223 optimizing some of the computing expensive parts.
229 Kernel devices and device nodes are connected now by reverse indizes in
230 /sys and /dev. A device number retrieved by a stat() or similar, the
231 kernel device directory can be found by looking up:
232 /sys/dev/{block,char}/<maj>:<min>
233 and the device node of the same device by looking up:
234 /dev/{block,char}/<maj>:<min>
238 Fix recently introduced bug, which caused a compilation without large
239 file support, where vol_id does not recognize raid signatures at the end
242 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
243 Seems some kernel versions prevent the creation of the ieee-* links,
244 so people used the scsi-* link which disappeared now.
246 More libudev work. Almost all udevadm functionality comes from libudev
249 udevadm trigger has a new option --type, which allows to trigger events
250 for "devices", for "subsystems", or "failed" devices. The old option
251 --retry-failed" still works, but is no longer mentioned in the man page.
257 The udevadm info --device-id-of-file= output has changed to use
258 the obvious format. Possible current users should use the --export
259 option which is not affected.
261 The old udev commands symlinks to udevadm are not installed, if
262 these symlinks are used, a warning is printed.
268 Optical drive's media is no longer probed for raid signatures,
269 reading the end of the device causes some devices to malfunction.
270 Also the offset of the last session found is used now to probe
273 The volume_id library got a major version number update to 1,
274 some deprecated functions are removed.
276 A shared library "libudev" gets installed now to provide access
277 to udev device information. DeviceKit, the successor of HAL, will
278 need this library to access the udev database and search sysfs for
280 The library is currently in an experimental state, also the API is
281 expected to change, as long as the DeviceKit integration is not
286 We use ./configure now. See INSTALL for details. Current
289 "/usr" - prefix for man pages, include files
291 "" - the root filesystem, prefix for libs and binaries
295 "lib" - directory name for libraries, not a path name
296 multilib 64bit systems may use "lib64" instead of "lib"
298 compile-in verbose debug messages
300 disable all logging and compile-out all log strings
302 link against SELInux libraries, to set the expected context
305 In the default rules, the group "disk" gets permissions 0660 instead
306 of 0640. One small step closer to unify distro rules. Some day, all
307 distros hopefully end up with the same set of rules.
309 No symlinks to udevadm are installed anymore, if they are still needed,
310 they should be provided by the package.
316 Default udev rules, which are not supposed to be edited by the user, should
317 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
318 the udev package and will be replaced with an update. Udev will pick up rule
320 /lib/udev/rules.d/ - default installed rules
321 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
322 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
323 It does not matter in which directory a rule file lives, all files are sorted
326 To help creating /dev/root, we have now:
327 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
330 In case the current --device-id-of-file is already used, please switch to
331 the --export format version, it saves the output parsing and the old
332 format will be changed to use ':' as a separator, like the format in the
337 Fix cdrom_id to properly recognize blank media.
343 Tape drive id-data is queried from /dev/bsg/* instead of the tape
344 nodes. This avoids rewinding tapes on open().
350 The symlinks udevcontrol and udevtrigger are no longer installed by
353 The scsi_id program does not depend on sysfs anymore. It can speak
354 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
355 data, which should solve some old problems with tape devices, where
356 we better do not open all tape device nodes to identify the device.
362 The cdrom_id program is replaced by an advanced version, which can
363 detect most common device types, and also properties of the inserted
364 media. This is part of moving some basic functionality from HAL into
365 udev (and the kernel).
371 The last WAIT_FOR_SYSFS rule is removed from the default rules.
373 The symlinks to udevadm for the debugging tools: udevmonitor and
374 udevtest are no longer created.
376 The symlinks to the udevadm man page for the old tool names are
379 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
380 should be prefixed with '@' to indicate that the path is not a
391 Udevstart is removed from the tree, it did not get installed for
392 a long time now, and is long replaced by trigger and settle.
398 All udev tools are merged into a single binary called udevadm.
399 The old names of the tools are built-in commands in udevadm now.
400 Symlinks to udevadm, with the names of the old tools, provide
401 the same functionality as the standalone tools. There is also
402 only a single udevadm.8 man page left for all tools.
404 Tools like mkinitramfs should be checked, if they need to include
405 udevadm in the list of files.
415 The etc/udev/rules.d/ directory now contains a default set of basic
416 udev rules. This initial version is the result of a rules file merge
417 of Fedora and openSUSE. For these both distros only a few specific
418 rules are left in their own file, named after the distro. Rules which
419 are optionally installed, because they are only valid for a specific
420 architecture, or rules for subsystems which are not always used are
421 in etc/udev/packages/.
427 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
428 actions by dynamically created rules.
430 SYMLINK=="<value>" matches agains the entries in the list of
431 currently defined symlinks. The links are not created in the
432 filesystem at that point in time, but the values can be matched.
434 RUN{ignore_error}+="<program>" will ignore any exit code from the
435 program and not record as a failed event.
441 Final merge of patches/features from the Ubuntu package.
447 Control characters in filesystem label strings are no longer silenty
448 removed, but hex-encoded, to be able to uniquely identify the device
449 by its symlink in /dev/disk/by-label/.
450 If libvolume_id is used by mount(8), LABEL= will work as expected,
451 if slashes or other characters are used in the label string.
453 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
454 can be specified now. The TEST key accepts an optional mode mask
455 TEST{0100}=="<is executable file>".
457 Scsi_id now supports a mode without expecting scsi-specific sysfs
458 entries to allow the extraction of cciss-device persistent properties.
464 In the future, we may see uuid's which are just simple character
465 strings (see the DDF Raid Specification). For that reason vol_id now
466 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
467 the creation of symlinks, the *_SAFE values ensure, that no control
468 or whitespace characters are used in the filename.
470 Possible users of libvolume_id, please use the volume_id_get_* functions.
471 The public struct will go away in a future release of the library.
477 Removal of useless extras/eventrecorder.sh.
487 The directory multiplexer for dev.d/ and hotplug.d are finally removed
488 from the udev package.
494 Symlinks can have priorities now, the priority is assigned to the device
495 and specified with OPTIONS="link_priority=100". Devices with higher
496 priorities overwrite the symlinks of devices with lower priorities.
497 If the device that currently owns the link, goes away, the symlink
498 will be removed, and recreated, pointing to the next device with the
499 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
500 more reliable, if multiple devices contain the same metadata and overwrite
503 The dasd_id program is removed from the udev tree, and dasdinfo, with the
504 needed rules, are part of the s390-tools now.
506 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
507 we may get the scsi sysfs mess fixed some day, and this will only catch
508 the devices we are looking for.
510 USB serial numbers for storage devices have the target:lun now appended,
511 to make it possibble to distinguish broken multi-lun devices with all
512 the same SCSI identifiers.
514 Note: The extra "run_directory" which searches and executes stuff in
515 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
516 with the next release. Make sure, that you don't use it anymore, or
517 provides your own implementation of that inefficient stuff.
518 We are tired of reports about a "slow udev", because these directories
519 contain stuff, that runs with _every_ event, instead of using rules,
520 that run programs only for the matching events.
530 DRIVER== will match only for devices that actually have a real
531 driver. DRIVERS== must be used, if parent devices should be
532 included in the match.
534 Libvolume_id's "linux_raid" detection needed another fix.
542 Add additional check to volume_id detection of via_raid, cause
543 some company decided to put a matching pattern all over the empty
544 storage area of their music players.
548 Fix path_id for SAS devices.
552 The udev daemon can be started with --debug-trace now, which will
553 execute all events serialized to get a chance to catch a possible
554 action that crashes the box.
556 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
557 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
558 are excluded from the warning. Referencing parent attributes directly
559 may break when something in the kernel driver model changes. Udev will
560 just find the attribute by walking up the parent chain.
562 Udevtrigger now sorts the list of devices depending on the device
563 dependency, so a "usb" device is triggered after the parent "pci"
568 Revert persistent-storage ata-serial '_' '-' replacement.
574 Udevtrigger can now filter the list of devices to be triggered. Matches
575 for subsystems or sysfs attributes can be specified.
577 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
578 zero-sized files to avoid pointing to /sys and confuse broken tools which
579 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
582 The rules and scripts to create udev rules for persistent network
583 devices and optical drives are in the extras/rules_generator directory
584 now. If you use something similar, please consider replacing your own
585 version with this, to share the support effort. The rule_generator
586 installs its own rules into /etc/udev/rules.d.
588 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
589 the rule_generator depends on cdrom_id to be called in an earlier rule.
595 Renaming of some key names (the old names still work):
596 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
597 (The behavior of the key DRIVER will change soon in one of the next
598 releases, to match only the event device, please switch to DRIVERS
599 instead. If DRIVER is used, it will behave like DRIVERS, but an error
601 With the new key names, we have a more consistent and simpler scheme.
602 We can match the properties of the event device only, with: KERNEL,
603 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
604 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
605 longer mentioned in the man page and should be switched in the rule
608 ATTR{file}="value" can be used now, to write to a sysfs file of the
609 event device. Instead of:
610 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
612 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
614 All the PHYSDEV* keys are deprecated and will be removed from a
616 PHYDEVPATH - is the path of a parent device and should not be
618 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
619 matched with SUBSYSTEMS==
620 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
621 Newer kernels will have DRIVER in the environment,
622 for older kernels udev puts in. Class device will
623 no longer carry this property of a parent and
624 DRIVERS== can be used to match such a parent value.
625 Note that ENV{DRIVER} is only available for a few bus devices, where
626 the driver is already bound at device event time. On coldplug, the
627 events for a lot devices are already bound to a driver, and they will have
628 that value set. But on hotplug, at the time the kernel creates the device,
629 it can't know what driver may claim the device after that, therefore
630 in most cases it will be empty.
632 Failed events should now be re-triggered with:
633 udevtrigger --retry-failed.
634 Please switch to this command, so we keep the details of the /dev/.udev/failed/
635 files private to the udev tools. We may need to switch the current symlink
636 target, cause some obviously broken tools try to scan all files in /dev
637 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
638 million times. This takes ages on slow boxes.
640 The udevinfo attribute walk (-a) now works with giving a device node
641 name (-n) instead of a devpath (-p). The query now always works, also when
642 no database file was created by udev.
644 The built-in /etc/passwd /etc/group parser is removed, we always depend on
645 getpwnam() and getgrnam() now. One of the next releases will depend on
646 fnmatch() and may use getopt_long().
650 Bugfixes and small improvements.
654 Fix path_id for recent kernels.
660 Added support for swapping network interface names, by temporarily
661 renaming the device and wait for the target name to become free.
665 The built-in MODALIAS key and substitution is removed.
669 The binary firmware helper is replaced by the usual simple
670 shell script. Udevsend is removed from the tree.
678 Some more keys require the correct use of '==' and '=' depending
679 on the kind of operation beeing an assignment or a match. Rules
680 with invalid operations are skipped and logged to syslog. Please
681 test with udevtest if the parsing of your rules throws errors and
682 fix possibly broken rules.
686 Provide "udevsettle" to wait for all current udev events to finish.
687 It also watches the current kernel netlink queue by comparing the
688 even sequence number to make sure that there are no current pending
689 events that have not already arrived in the daemon.
693 Fix rule to skip persistent rules for removable IDE devices, which
694 also skipped optical IDE drives.
696 All *_id program are installed in /lib/udev/ by default now.
698 No binary is stripped anymore as this should be done in the
699 packaging process and not at build time.
701 libvolume_id is provided as a shared library now and vol_id is
702 linked against it. Also one of the next HAL versions will require
703 this library, and the HAL build process will also require the
704 header file to be installed. The copy of the same code in HAL will
705 be removed to have only a single copy left on the system.
709 Add persistent links for SCSI tapes. The rules file is renamed
710 to 60-persistent-storage.rules.
712 Create persistent path for usb devices. Can be used for all sorts
713 of devices that can't be distinguished by other properties like
714 multiple identical keyboards and mice connected to the same box.
716 Provide "udevtrigger" program to request events on coldplug. The
717 shell script is much too slow with thousends of devices.
721 Fix persistent disk rules to exclude removable IDE drives.
723 Warn if %e, $modalias or MODALIAS is used.
727 Fix queue export, which wasn't correct for subsequent add/remove
728 events for the same device.
732 Fix cramfs detection on big endian.
734 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
739 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
740 attributes were only checked at the parent device that matched the
741 by BUS requested subsystem. Fix it to also look at the device we
742 received the event for.
744 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
749 Fix a bug where NAME="" would prevent RUN from beeing executed.
751 RUN="/bin/program" does not longer automatically add the subsystem
752 as the first parameter. This is from the days of /sbin/hotplug
753 which is dead now and it's just confusing to need to add a space at
754 the end of the program name to prevent this.
755 If you use rules that need the subsystem as the first parameter,
756 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
757 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
761 The udev man page has moved to udev(7) as it does not describe a command
762 anymore. The programs udev, udevstart and udevsend are no longer installed
763 by default and must be copied manually, if they should be installed or
764 included in a package.
766 Fix a bug where "ignore_device" could run earlier collected RUN keys before
767 the ignore rule was applied.
769 More preparation for future sysfs changes. usb_id and scsi_id no longer
770 depend on a magic order of devices in the /devices chain. Specific devices
771 should be requested by their subsytem.
773 This will always find the scsi parent device without depending on a specific
775 dev = sysfs_device_get(devpath);
776 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
778 The "device" link in the current sysfs layout will be automatically
779 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
780 parent in the devpath. If a device is requested by it's symlink, like all
781 class devices in the new sysfs layout will look like, it gets automatically
782 resolved and substituted with the real devpath and not the symlink path.
785 A similar logic must be applied to _all_ sysfs users, including
786 scripts, that search along parent devices in sysfs. The explicit use of
787 the "device" link must be avoided. With the future sysfs layout all
788 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
789 back to the "class" or the "bus". The layout of the parent devices in
790 /devices is not necessarily expected to be stable across kernel releases and
791 searching for parents by their subsystem should make sysfs users tolerant
792 for changed parent chains.
796 Prepare udev to work with the experimental kernel patch, that moves
797 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
799 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
800 moving the class devices to /sys/devices.
802 Thanks again to Marco for help finding a hopefully nice compromise
803 to make %b simpler and working again.
807 Complete removal of libsysfs, replaced by simple helper functions
808 which are much simpler and a bit faster. The udev daemon operatesentirely
809 on event parameters and does not use sysfs for simple rules anymore.
810 Please report any new bugs/problems, that may be caused by this big
811 change. They will be fixed immediately.
813 The enumeration format character '%e' is deprecated and will be
814 removed sometimes from a future udev version. It never worked correctly
815 outside of udevstart, so we can't use it with the new parallel
816 coldplug. A simple enumeration is as useless as the devfs naming
817 scheme, just get rid of both if you still use it.
819 MODALIAS and $modalias is not needed and will be removed from one of
820 the next udev versions, replace it in all rules with ENV{MODALIAS} or
821 the sysfs "modalias" value.
823 Thanks a lot to Marco for all his help on finding and fixing bugs.
827 Let scsi_id request libata drive serial numbers from page 0x80.
829 Renamed etc/udev/persistent.rules to persistent-disk.rules and
830 added /dev/disk/by-name/* for device mapper device names.
832 Removed %e from the man page. It never worked reliably outside
833 of udevstart and udevstart is no longer recommended to use.
837 Symlinks are now exported to the event environment. Hopefully it's no
838 longer needed to run udevinfo from an event process, like it was
839 mentioned on the hotplug list:
840 UDEV [1134776873.702967] add@/block/sdb
843 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
847 Fix a problem if udevsend is used as the hotplug handler and tries to use
848 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
849 and this kind of problems will hopefully go away soon.
853 All built-in logic to work around bad sysfs timing is removed with this
854 version. The need to wait for sysfs files is almost fixed with a kernel
855 version that doesn't work with this udev version anyway. Until we fix
856 the timing of the "bus" link creation, the former integrated logic should
857 be emulated by a rule placed before all other rules:
858 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
860 The option "udev_db" does no longer exist. All udev state will be in
861 /$udev_root/.udev/ now, there is no longer an option to set this
863 If the init script or something else used this value, just depend on
864 this hardcoded path. But remember _all_content_ of this directory is
865 still private to udev and can change at any time.
867 Default location for rule sripts and helper programs is now: /lib/udev/.
868 Everything that is not useful on the commandline should go into this
869 directory. Some of the helpers in the extras folder are installed there
870 now. The rules need to be changed, to find the helpers there.
872 Also /lib/udev/devices is recommended as a directory where packages or
873 the user can place real device nodes, which get copied over to /dev at
874 every boot. This should replace the various solutions with custom config
877 Udevsend does no longer start the udev daemon. This must be done with
878 the init script that prepares /dev on tmpfs and creates the initial nodes,
879 before starting the daemon.
883 Silent a too verbose error logging for the old hotplug.d/ dev.d/
886 The copy of klibc is removed. A systemwide installed version of klibc
887 should be used to build a klibc udev now.
891 NAME="" will not create any nodes, but execute RUN keys. To completely
892 ignore an event the OPTION "ignore_device" should be used.
894 After removal of the reorder queue, events with a TIMEOUT can be executed
895 without any queuing now.
899 Fixed bug in udevd, if inotify is not available. We depend on netlink
900 uevents now, kernels without that event source will not work with that
901 version of udev anymore.
905 The rule parsing happens now in the daemon once at startup, all udev
906 event processes inherit the already parsed rules from the daemon.
907 It is shipped with SUSE10.0 and reduces heavily the system load at
908 startup. The option to save precompiled rules and let the udev process
909 pick the them up is removed, as it's no longer needed.
911 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
912 device. Libsysfs is changed to "translate" the requested link into the
913 real device path, as it would happen with the hotplug event. Otherwise
914 device removal and the udev database will not work.
916 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
919 A few improvements for vol_id, the filesytem probing code.
923 Fix a stupid typo in extras/run_directory for "make install".
925 scsi_id creates the temporary devnode now in /dev for usage with a
926 non-writable /tmp directory.
928 The uevent kernel socket buffer can carry app. 50.000 events now,
929 let's see who can break this again. :)
931 The upcoming kernel will have a new input driver core integration.
932 Some class devices are now symlinks to the real device. libsysfs
933 needs a fix for this to work correctly. Udevstart of older udev
934 versions will _not_ create these devices!
938 Fix a 'install' target in the Makefile, that prevents EXTRAS from
943 A bunch of mostly trivial bugfixes. From now on no node name or
944 symlink name can contain any character than plain whitelisted ascii
945 characters or validated utf8 byte-streams. This is needed for the
946 /dev/disk/by-label/* links, because we import untrusted data and
947 export it to the filesystem.
951 More bugfixes. If udevd was started from the kernel, we don't
952 have stdin/stdout/stderr, which broke the forked tools in some
957 Bugfix. udevstart event ordering was broken for a long time.
958 The new run_program() uncovered it, because /dev/null was not
959 available while we try to run external programs.
960 Now udevstart should create it before we run anything.
964 Minor bugfixes and some distro rules updates. If you don't have the
965 persistent disk rules in /dev/disk/by-*/* on your distro, just
966 grab it from here. :)
970 We can use socket communication now to pass events from udev to
972 RUN+="socket:/org/freedesktop/hal/udev_event"
973 will pass the whole udev event to the HAL daemon without the need
974 for a forked helper. (See ChangeLog for udevmonitor, as an example)
978 Mostly bugfixes and see ChangeLog.
980 The test for the existence of an environment value should be
982 ENV{KEY}=="*" to ENV{KEY}=="?*"
983 because "*" will not fail anymore, if the key does not exist or
988 Bugfixes and a few tweaks described in the ChangeLog.
992 Mostly a Bugfix release.
994 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
995 timing with custom rules.
999 We changed the internal rule storage format. Our large rule files took
1000 2 MB of RAM, with the change we are down to 99kB.
1002 If the device-node has been created with default name and no symlink or
1003 options are to remenber, it is not longer stored in the udevdb. HAL will
1004 need to be updated to work correctly with that change.
1006 To overrride optimization flags, OPTFLAGS may be used now.
1014 Major changes happened with this release. The goal is to take over the
1015 complete kernel-event handling and provide a more efficient way to dispatch
1016 kernel events. Replacing most of the current shell script logic and the
1017 kernel forked helper with a netlink-daemon and a rule-based event handling.
1019 o udevd listens to netlink events now. The first valid netlink event
1020 will make udevd ignore any message from udevsend that contains a
1021 SEQNUM, to avoid duplicate events. The forked events can be disabled
1023 echo "" > /proc/sys/kernel/hotplug
1024 For full support, the broken input-subsytem needs to be fixed, not to
1025 bypass the driver core.
1027 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1028 removed from udev itself and must be emulated by calling small
1029 helper binaries provided in the extras folder:
1030 make EXTRAS=extras/run_directory/
1031 will build udev_run_devd and udev_run_hotplugd, which can be called
1032 from a rule if needed:
1033 RUN+="/sbin/udev_run_hotplugd"
1034 The recommended way to handle this is to convert all the calls from
1035 the directories to explicit udev rules and get completely rid of the
1036 multiplexing. (To catch a ttyUSB event, you now no longer need to
1037 fork and exit 300 tty script instances you are not interested in, it
1038 is just one rule that matches exactly the device.)
1040 o udev handles now _all_ events not just events for class and block
1041 devices, this way it is possible to control the complete event
1042 behavior with udev rules. Especially useful for rules like:
1043 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1045 o As used in the modalias rule, udev supports now textual
1046 substitution placeholder along with the usual format chars. This
1047 needs to be documented, for now it's only visible in udev_rules_parse.c.
1049 o The rule keys support now more operations. This is documented in the
1050 man page. It is possible to add values to list-keys like the SYMLINK
1051 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1052 Also "final"-assignments are supported by using KEY:="value", which will
1053 prevent changing the key by any later rule.
1055 o kernel 2.6.12 has the "detached_state" attribute removed from
1056 sysfs, which was used to recognize sysfs population. We switched that
1057 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1058 Running this udev version on older kernels may cause a short delay for
1061 o To provide infrastructure for persistent device naming, the id programs:
1062 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1063 to export the probed data in environment key format:
1064 pim:~ # /sbin/ata_id --export /dev/hda
1065 ID_MODEL=HTS726060M9AT00
1066 ID_SERIAL=MRH401M4G6UM9B
1067 ID_REVISION=MH4OA6BA
1069 The following rules:
1070 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1071 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1074 kay@pim:~> tree /dev/disk
1077 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1078 | `-- IBM-Memory_Key -> ../../sda
1080 | |-- swap -> ../../hda1
1081 | |-- date -> ../../sda1
1082 | `-- home -> ../../hda3
1084 |-- 2E08712B0870F2E7 -> ../../hda3
1085 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1086 |-- E845-7A89 -> ../../sda1
1087 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1089 The IMPORT= operation will import these keys in the environment and make
1090 it available for later PROGRAM= and RUN= executed programs. The keys are
1091 also stored in the udevdb and can be queried from there with one of the
1094 o A few binaries are silently added to the repository, which can be used
1095 to replay kernel events from initramfs instead of using coldplug. udevd
1096 can be instructed now to queue-up events while the stored events from
1097 initramfs are filled into the udevd-queue. This code is still under
1098 development and there is no documentation now besides the code itself.
1099 The additional binaries get compiled, but are not installed by default.
1101 o There is also a temporary fix for a performance problem where too many
1102 events happen in parallel and every event needs to parse the rules.
1103 udev can now read precompiled rules stored on disk. This is likely to be
1104 replaced by a more elegant solution in a future udev version.
1108 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1109 Fix for libsysfs not to expect this file was added.
1113 All rules are applied now, but only the first matching rule with a NAME-key
1114 will be applied. All later rules with NAME-key are completely ignored. This
1115 way system supplied symlinks or permissions gets applied to user-defined
1119 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1120 to some rules, to keep the old behavior.
1122 The rules are read on "remove"-events too. That makes is possible to match
1123 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1124 instruct udev to ignore an event (OPTIONS="ignore_device").
1125 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1127 The new RUN-key supports rule-based execution of programs after device-node
1128 handling. This is meant as a general replacement for the dev.d/-directories
1129 to give fine grained control over the execution of programs.
1131 The %s{}-sysfs format char replacement values are searched at any of the
1132 devices in the device chain now, not only at the class-device.
1134 We support log priority levels now. The value udev_log in udev.conf is used
1135 to determine what is printed to syslog. This makes it possible to
1136 run a version with compiled-in debug messages in a production environment
1137 which is sometimes needed to find a bug.
1138 It is still possible to supress the inclusion of _any_ syslog usage with
1139 USE_LOG=false to create the smallest possible binaries if needed.
1140 The configured udev_log value can be overridden with the environment variable
1145 Possible use of a system-wide klibc:
1146 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1147 will link against an external klibc and our own version will be ignored.
1151 We support an unlimited count of symlinks now.
1153 If USE_STATIC=true is passed to a glibc build, we link statically and use
1154 a built-in userdb parser to resolve user and group names.
1156 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1157 we walk up the chain of physical devices to find a match.
1159 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1160 easy to skip certain attribute matches without composing rules with weird
1161 character class negations like:
1162 KERNEL="[!s][!c][!d]*"
1163 this can now be replaced with:
1165 The current simple '=' is still supported, and should work as it does today,
1166 but existing rules should be converted if possible, to be better readable.
1168 We have new ENV{}== key now, to match against a maximum of 5 environment
1171 udevstart is its own binary again, because we don't need co carry this araound
1172 with every forked event.