5 The path_id, usb_id, input_id tools are built-in commands now
6 and the stand-alone tools do not exist anymore. For testing,
7 the commands can be run with 'udevadm test-builtin <cmd>'.
13 The udev-acl extra is no longer enabled by default now. To enable it,
14 --enable-udev_acl needs to be given at ./configure time. On systemd
15 systems, the udev-acl rules prevent it from running as the functionality
22 Udev now enables kernel media-presence polling if available. Part
23 of udisks optical drive tray-handling moved to cdrom_id: The tray
24 is locked as soon as a media is detected to enable the receiving
25 of media-eject-request events. Media-eject-request events will
28 Libudev enumerate is now able to enumerate a subtree of a given
31 The mobile-action-modeswitch modeswitch tool was deleted. The
32 functionality is provided by usb_modeswitch now.
38 The systemd service files require systemd version 28. The systemd
39 socket activation make it possible now to start 'udevd' and 'udevadm
44 Fix bug in control message handling, which can lead to a failing
45 udevadm control --exit. Thanks to Jürg Billeter for help tracking
52 We require at least Linux kernel 2.6.32 now. Some platforms might
53 require a later kernel that supports accept4() and similar, or
54 need to backport the trivial syscall wiring to the older kernels.
56 The hid2hci tool moved to the bluez package and was removed.
58 Many of the extras can be --enable/--disabled at ./configure
59 time. The --disable-extras option was removed. Some extras have
60 been disabled by default. The current options and their defaults
61 can be checked with './configure --help'.
67 Udev logs a warning now if /run is not writable at udevd
68 startup. It will still fall back to /dev/.udev, but this is
71 The running udev daemon can now cleanly shut down with:
72 udevadm control --exit
74 Udev in initramfs should clean the state of the udev database
75 with: udevadm info --cleanup-db which will remove all state left
76 behind from events/rules in initramfs. If initramfs uses
77 --cleanup-db and device-mapper/LVM, the rules in initramfs need
78 to add OPTIONS+="db_persist" for all dm devices. This will
79 prevent removal of the udev database for these devices.
81 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
82 120 seconds per process. If that timeout is reached the spawned
83 process will be killed. The event timeout can be overwritten with
86 If systemd is used, udev gets now activated by netlink data.
87 Systemd will bind the netlink socket which will buffer all data.
88 If needed, such setup allows a seemless update of the udev daemon,
89 where no event can be lost during a udevd update/restart.
90 Packages need to make sure to: systemctl stop udev.socket udev.service
91 or 'mask' udev.service during the upgrade to prevent any unwanted
92 auto-spawning of udevd.
93 This version of udev conflicts with systemd version below 25. The
94 unchanged service files will not wirk correctly.
100 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
101 /run mountpoint is supposed to be a tmpfs mounted during early boot,
102 available and writable to for all tools at any time during bootup,
103 it replaces /var/run/, which should become a symlink some day.
105 If /run does not exist, or is not writable, udev will fall back using
108 On systemd systems with initramfs and LVM used, packagers must
109 make sure, that the systemd and initramfs versions match. The initramfs
110 needs to create the /run mountpoint for udev to store the data, and
111 mount this tmpfs to /run in the rootfs, so the that the udev database
112 is preserved for the udev version started in the rootfs.
114 The command 'udevadm info --convert-db' is gone. The udev daemon
115 itself, at startup, converts any old database version if necessary.
117 The systemd services files have been reorganized. The udev control
118 socket is bound by systemd and passed to the started udev daemon.
119 The udev-settle.service is no longer active by default. Services which
120 can not handle hotplug setups properly need to actively pull it in, to
121 act like a barrier. Alternatively the settle service can be unconditionally
122 'systemctl'enabled, and act like a barrier for basic.target.
124 The fstab_import callout is no longer built or installed. Udev
125 should not be used to mount, does not watch changes to fstab, and
126 should not mirror fstab values in the udev database.
132 New and updated keymaps.
138 The udev database has changed, After installation of a new udev
139 version, 'udevadm info --convert-db' should be called, to let the new
140 udev/libudev version read the already stored data.
142 udevadm now supports quoting of property values, and prefixing of
144 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
147 MY_DEVNAME='/dev/sda'
151 libudev now supports:
152 udev_device_get_is_initialized()
153 udev_enumerate_add_match_is_initialized()
154 to be able to skip devices the kernel has created , but udev has
157 libudev now supports:
158 udev_device_get_usec_since_initialized()
159 to retrieve the "age" of a udev device record.
161 GUdev supports a more generic GUdevEnumerator class, udev TAG
162 handling, device initialization and timestamp now.
164 The counterpart of /sys/dev/{char,block}/$major:$minor,
165 /dev/{char,block}/$major:$minor symlinks are now unconditionally
166 created, even when no rule files exist.
168 New and updated keymaps.
174 GUdev moved from /usr to /.
184 Persistent network naming rules are disabled inside of Qemu/KVM now.
186 New and updated keymaps.
188 Udev gets unconditionally enabled on systemd installations now. There
189 is no longer the need to to run 'systemctl enable udev.service'.
203 New and fixed keymaps.
205 Install systemd service files if applicable.
211 All distribution specific rules are removed from the udev source tree,
212 most of them are no longer needed. The Gentoo rules which allow to support
213 older kernel versions, which are not covered by the default rules anymore
214 has moved to rules/misc/30-kernel-compat.rules.
220 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
221 was removed from udevd.
223 Udevd now checks the kernel commandline for the following variables:
224 udev.log-priority=<syslog priority>
225 udev.children-max=<maximum number of workers>
226 udev.exec-delay=<seconds to delay the execution of RUN=>
227 to help debuging coldplug setups where the loading of a kernel
228 module crashes the system.
230 The subdirectory in the source tree rules/packages has been renamed to
231 rules/arch, anc contains only architecture specific rules now.
241 Now the udev daemon itself, does on startup:
242 - copy the content of /lib/udev/devices to /dev
243 - create the standard symlinks like /dev/std{in,out,err},
244 /dev/core, /dev/fd, ...
245 - use static node information provided by kernel modules
246 and creates these nodes to allow module on-demand loading
247 - possibly apply permissions to all ststic nodes from udev
248 rules which are annotated to match a static node
250 The default mode for a device node is 0600 now to match the kernel
251 created devtmpfs defaults. If GROUP= is specified and no MODE= is
252 given the default will be 0660.
258 Udev now gradually starts to pass control over the primary device nodes
259 and their names to the kernel, and will in the end only manage the
260 permissions of the node, and possibly create additional symlinks.
261 As a first step NAME="" will be ignored, and NAME= setings with names
262 other than the kernel provided name will result in a logged warning.
263 Kernels that don't provide device names, or devtmpfs is not used, will
264 still work as they did before, but it is strongly recommended to use
265 only the same names for the primary device node as the recent kernel
266 provides for all devices.
270 Fix broken firmware loader search path.
276 "udevadm trigger" defaults to "change" events now instead of "add"
277 events. The "udev boot script" might need to add "--action=add" to
278 the trigger command if not already there, in case the initial coldplug
279 events are expected as "add" events.
281 The option "all_partitons" was removed from udev. This should not be
282 needed for usual hardware. Udev can not safely make assumptions
283 about non-existing partition major/minor numbers, and therefore no
284 longer provide this unreliable and unsafe option.
286 The option "ignore_remove" was removed from udev. With devtmpfs
287 udev passed control over device nodes to the kernel. This option
288 should not be needed, or can not work as advertised. Neither
289 udev nor the kernel will remove device nodes which are copied from
290 the /lib/udev/devices/ directory.
292 All "add|change" matches are replaced by "!remove" in the rules and
293 in the udev logic. All types of events will update possible symlinks
294 and permissions, only "remove" is handled special now.
296 The modem modeswitch extra was removed and the external usb_modeswitch
297 program should be used instead.
299 New and fixed keymaps.
309 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
310 depend on the current sysfs layout and the information not available in the
311 deprecated layout. All remaining support for the deprecated sysfs layout is
316 Fix for a possible endless loop in the new input_id program.
322 The option "ignore_device" does no longer exist. There is no way to
323 ignore an event, as libudev events can not be suppressed by rules.
324 It only prevented RUN keys from being executed, which results in an
325 inconsistent behavior in current setups.
327 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
328 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
331 The support for the deprecated IDE devices has been removed from the
332 default set of rules. Distros who still care about non-libata drivers
333 need to add the rules to the compat rules file.
335 The ID_CLASS property on input devices has been replaced by the more accurate
336 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
337 determined by the new "input_id" prober now. Some devices, such as touchpads,
338 can have several classes. So if you previously had custom udev rules which e. g.
339 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
340 ENV{ID_INPUT_KEYBOARD}=="?*".
346 To support DEVPATH strings larger than the maximum file name length, the
347 private udev database format has changed. If some software still reads the
348 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
349 Please do not port anything to the new format again, everything in /dev/.udev
350 is and always was private to udev, and may and will change any time without
353 Multiple devices claiming the same names in /dev are limited to symlinks
354 only now. Mixing identical symlink names and node names is not supported.
355 This reduces the amount of data in the database significantly.
357 NAME="%k" causes a warning now. It's is and always was completely superfluous.
358 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
361 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
362 if they are not the default. To support older kernels, the NAME= rules need to
363 be added to the compat rules file.
365 Symlinks to udevadm with the old command names are no longer resolved to
366 the udevadm commands.
368 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
371 The option "last_rule" does no longer exist. Its use breaks too many
372 things which expect to be run from independent later rules, and is an idication
373 that something needs to be fixed properly instead.
375 The gudev API is no longer marked as experimental,
376 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
377 is enabled by default now. Various projects already depend on introspection
378 information to bind dynamic languages to the gudev interfaces.
384 The udevadm trigger "--retry-failed" option, which is replaced since quite
385 a while by "--type=failed" is removed.
387 The failed tracking was not working at all for a few releases. The RUN
388 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
389 default is not to track any failing RUN executions.
391 New keymaps, new modem, hid2hci updated.
395 Fix possible crash in udevd when worker processes are busy, rules are
396 changed at the same time, and workers get killed to reload the rules.
402 Properties set with ENV{.FOO}="bar" are marked private by starting the
403 name with a '.'. They will not be stored in the database, and not be
404 exported with the event.
406 Firmware files are looked up in:
407 /lib/firmware/updates/$(uname -r)
408 /lib/firmware/updates
409 /lib/firmware/$(uname -r)
413 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
414 ata_id, instead of scsi_id, is the default tool now for ATA devices.
420 The configure options have changed because another library needs to be
421 installed in a different location. Instead of exec_prefix and udev_prefix,
422 libdir, rootlibdir and libexecdir are used. The Details are explained in
425 Event processes now get re-used after they handled an event. This reduces
426 the number of forks and the pressure on the CPU significantly, because
427 cloned event processes no longer cause page faults in the main daemon.
428 After the events have settled, a few worker processes stay around for
429 future events, all others get cleaned up.
431 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
432 Also inotify support is mandatory now to run udev.
434 The format of the queue exported by the udev damon has changed. There is
435 no longer a /dev/.udev/queue/ directory. The current event queue can be
436 accessed with udevadm settle and libudedv.
438 Libudev does not have the unstable API header anymore. From now on,
439 incompatible changes will be handled by bumping the library major version.
441 To build udev from the git tree gtk-doc is needed now. The tarballs will
442 build without it and contain the pre-built documentation. An online copy
444 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
446 The tools from the udev-extras repository have been merged into the main
447 udev repository. Some of the extras have larger external dependencies, and
448 they can be disabled with the configure switch --disable-extras.
454 The program vol_id and the library libvolume_id are removed from the
455 repository. Libvolume_id is merged with libblkid from the util-linux-ng
456 package. Persistent disk links for label and uuid depend on the
457 util-linux-ng version (2.15) of blkid now. Older versions of blkid
458 can not be used with udev.
460 Libudev allows to subscribe to udev events. To prevent unwanted messages
461 to be delivered, and waking up the subscribing process, a filter can be
462 installed, to drop messages inside a kernel socket filter. The filters
463 match on the <subsytem>:<devtype> properties of the device.
464 This is part of the ongoing effort to replace HAL, and switch current
465 users over to directly use libudev.
466 Libudev is still marked as experimental, and its interface might
467 eventually change if needed, but no major changes of the currently exported
468 interface are expected anymore, and a first stable release should happen
471 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
472 is not supported since while and udevd will log an error message at
473 startup. It should still be able to boot-up, but advanced rules and system
474 services which depend on the information not available in the old sysfs
475 format will fail to work correctly.
477 DVB device naming is supplied by the kernel now. In case older kernels
478 need to be supported, the old shell script should be added to a compat
485 The processed udev events get send back to the netlink socket. Libudev
486 provides access to these events. This is work-in-progress, to replace
487 the DeviceKit daemon functionality directly with libudev. There are
488 upcoming kernel changes to allow non-root users to subcribe to these
495 "udevadm settle" now optionally accepts a range of events to wait for,
496 instead of waiting for "all" events.
502 The installed watch for block device metadata changes is now removed
503 during event hadling, because some (broken) tools may be called from udev
504 rules and (wrongly) open the device with write access. After the finished
505 event handling the watch is restored.
511 Device nodes can be watched for changes with inotify with OPTIONS="watch".
512 If closed after being opened for writing, a "change" uevent will occur.
513 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
519 The udevadm test command has no longer a --force option, nodes and symlinks
520 are always updated with a test run now.
522 The udevd daemon can be started with --resolve-names=never to avoid all user
523 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
524 lookup user and groups every time events are handled.
530 We are currently merging the Ubuntu rules in the udev default rules,
531 and get one step closer to provide a common Linux /dev setup, regarding
532 device names, symlinks, and default device permissions. On udev startup,
533 we now expect the following groups to be resolvable to their ids with
535 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
536 LDAP setups need to make sure, that these groups are always resolvable at
537 bootup, with only the rootfs mounted, and without network access available.
539 Some systems may need to add some new, currently not used groups, or need
540 to add some users to new groups, but the cost of this change is minimal,
541 compared to the pain the current, rather random, differences between the
542 various distributions cause for upstream projects and third-party vendors.
544 In general, "normal" users who log into a machine should never be a member
545 of any such group, but the device-access should be managed by dynamic ACLs,
546 which get added and removed for the specific users on login/logout and
547 session activity/inactivity. These groups are only provided for custom setups,
548 and mainly system services, to allow proper privilege separation.
549 A video-streaming daemon uid would be a member of "audio" and "video", to get
550 access to the sound and video devices, but no "normal" user should ever belong
551 to the "audio" group, because he could listen to the built-in microphone with
552 any ssh-session established from the other side of the world.
554 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
555 which do not depend on the kernel device name. As usual, unique
556 devices - only a single one per product connected, or a real
557 USB serial number in the device - are always found with the same
558 name in the by-id/ directory.
559 Completely identical devices may overwrite their names in by-id/
560 and can only be found reliably in the by-path/ directory. Devices
561 specified by by-path/ must not change their connection, like the
562 USB port number they are plugged in, to keep their name.
564 To support some advanced features, Linux 2.6.22 is the oldest supported
565 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
566 supported. Older kernels should still work, and devices nodes should be
567 reliably created, but some rules and libudev will not work correctly because
568 the old kernels do not provide the expected information or interfaces.
574 Fix for a possible segfault while swapping network interface names in udev
581 The group "video" is part of the default rules now.
585 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
586 block devices in some cases. No common distro uses this option anymore,
587 and we do not get enough testing for this and recent udev versions. If
588 this option is not needed to run some old distro with a new kernel,
589 it should be disabled in the kernel config.
591 Bugfix for the $links substitution variable, which may crash if no links
592 are created. This should not happen in usual setups because we always
593 create /dev/{block,char}/ links.
595 The strings of the parsed rules, which are kept in memory, no longer
596 contain duplicate entries, or duplicate tails of strings. This, and the
597 new rules parsing/matching code reduces the total in-memory size of
598 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
601 The export of DEVTYPE=disk/partition got removed from the default
602 rules. This value is available from the kernel. The pnp shell script
603 modprobe hack is removed from the default rules. ACPI devices have _proper_
604 modalias support and take care of the same functionality.
605 Installations which support old kernels, but install current default
606 udev rules may want to add that to the compat rules file.
608 Libvolume_id now always probes for all known filesystems, and does not
609 stop at the first match. Some filesystems are marked as "exclusive probe",
610 and if any other filesytem type matches at the same time, libvolume_id
611 will, by default, not return any probing result. This is intended to prevent
612 mis-detection with conflicting left-over signatures found from earlier
613 file system formats. That way, we no longer depend on the probe-order
614 in case of multiple competing signatures. In some setups the kernel allows
615 to mount a volume with just the old filesystem signature still in place.
616 This may damage the new filesystem and cause data-loss, just by mounting
617 it. Because volume_id can not decide which one the correct signature is,
618 the wrong signatures need to be removed manually from the volume, or the
619 volume needs to be reformatted, to enable filesystem detection and possible
624 Fix segfault if compiled without optimization and dbg() does not get
625 compiled out and uses variables which are not available.
629 Bugfixes. (And maybe new bugs. :))
631 The rule matching engine got converted from a rule list to a token
632 array which reduced the in-memory rules representation of a full
633 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
634 Limits like 5 ENV and ATTR matches, and one single instance for most
635 other keys per rule are gone.
637 The NAME assignment is no longer special cased. If later rules assign
638 a NAME value again, the former value will be overwritten. As usual
639 for most other keys, the NAME value can be protected by doing a final
640 assignment with NAME:="<value>".
642 All udev code now uses libudev, which is also exported. The library
643 is still under development, marked as experimental, and its interface
644 may change as long as the DeviceKit integration is not finished.
646 Many thanks to Alan Jenkins for his continuous help, and finding and
647 optimizing some of the computing expensive parts.
653 Kernel devices and device nodes are connected now by reverse indizes in
654 /sys and /dev. A device number retrieved by a stat() or similar, the
655 kernel device directory can be found by looking up:
656 /sys/dev/{block,char}/<maj>:<min>
657 and the device node of the same device by looking up:
658 /dev/{block,char}/<maj>:<min>
662 Fix recently introduced bug, which caused a compilation without large
663 file support, where vol_id does not recognize raid signatures at the end
666 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
667 Seems some kernel versions prevent the creation of the ieee-* links,
668 so people used the scsi-* link which disappeared now.
670 More libudev work. Almost all udevadm functionality comes from libudev
673 udevadm trigger has a new option --type, which allows to trigger events
674 for "devices", for "subsystems", or "failed" devices. The old option
675 --retry-failed" still works, but is no longer mentioned in the man page.
681 The udevadm info --device-id-of-file= output has changed to use
682 the obvious format. Possible current users should use the --export
683 option which is not affected.
685 The old udev commands symlinks to udevadm are not installed, if
686 these symlinks are used, a warning is printed.
692 Optical drive's media is no longer probed for raid signatures,
693 reading the end of the device causes some devices to malfunction.
694 Also the offset of the last session found is used now to probe
697 The volume_id library got a major version number update to 1,
698 some deprecated functions are removed.
700 A shared library "libudev" gets installed now to provide access
701 to udev device information. DeviceKit, the successor of HAL, will
702 need this library to access the udev database and search sysfs for
704 The library is currently in an experimental state, also the API is
705 expected to change, as long as the DeviceKit integration is not
710 We use ./configure now. See INSTALL for details. Current
713 "/usr" - prefix for man pages, include files
715 "" - the root filesystem, prefix for libs and binaries
719 "lib" - directory name for libraries, not a path name
720 multilib 64bit systems may use "lib64" instead of "lib"
722 compile-in verbose debug messages
724 disable all logging and compile-out all log strings
726 link against SELInux libraries, to set the expected context
729 In the default rules, the group "disk" gets permissions 0660 instead
730 of 0640. One small step closer to unify distro rules. Some day, all
731 distros hopefully end up with the same set of rules.
733 No symlinks to udevadm are installed anymore, if they are still needed,
734 they should be provided by the package.
740 Default udev rules, which are not supposed to be edited by the user, should
741 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
742 the udev package and will be replaced with an update. Udev will pick up rule
744 /lib/udev/rules.d/ - default installed rules
745 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
746 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
747 It does not matter in which directory a rule file lives, all files are sorted
750 To help creating /dev/root, we have now:
751 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
754 In case the current --device-id-of-file is already used, please switch to
755 the --export format version, it saves the output parsing and the old
756 format will be changed to use ':' as a separator, like the format in the
761 Fix cdrom_id to properly recognize blank media.
767 Tape drive id-data is queried from /dev/bsg/* instead of the tape
768 nodes. This avoids rewinding tapes on open().
774 The symlinks udevcontrol and udevtrigger are no longer installed by
777 The scsi_id program does not depend on sysfs anymore. It can speak
778 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
779 data, which should solve some old problems with tape devices, where
780 we better do not open all tape device nodes to identify the device.
786 The cdrom_id program is replaced by an advanced version, which can
787 detect most common device types, and also properties of the inserted
788 media. This is part of moving some basic functionality from HAL into
789 udev (and the kernel).
795 The last WAIT_FOR_SYSFS rule is removed from the default rules.
797 The symlinks to udevadm for the debugging tools: udevmonitor and
798 udevtest are no longer created.
800 The symlinks to the udevadm man page for the old tool names are
803 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
804 should be prefixed with '@' to indicate that the path is not a
815 Udevstart is removed from the tree, it did not get installed for
816 a long time now, and is long replaced by trigger and settle.
822 All udev tools are merged into a single binary called udevadm.
823 The old names of the tools are built-in commands in udevadm now.
824 Symlinks to udevadm, with the names of the old tools, provide
825 the same functionality as the standalone tools. There is also
826 only a single udevadm.8 man page left for all tools.
828 Tools like mkinitramfs should be checked, if they need to include
829 udevadm in the list of files.
839 The etc/udev/rules.d/ directory now contains a default set of basic
840 udev rules. This initial version is the result of a rules file merge
841 of Fedora and openSUSE. For these both distros only a few specific
842 rules are left in their own file, named after the distro. Rules which
843 are optionally installed, because they are only valid for a specific
844 architecture, or rules for subsystems which are not always used are
845 in etc/udev/packages/.
851 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
852 actions by dynamically created rules.
854 SYMLINK=="<value>" matches agains the entries in the list of
855 currently defined symlinks. The links are not created in the
856 filesystem at that point in time, but the values can be matched.
858 RUN{ignore_error}+="<program>" will ignore any exit code from the
859 program and not record as a failed event.
865 Final merge of patches/features from the Ubuntu package.
871 Control characters in filesystem label strings are no longer silenty
872 removed, but hex-encoded, to be able to uniquely identify the device
873 by its symlink in /dev/disk/by-label/.
874 If libvolume_id is used by mount(8), LABEL= will work as expected,
875 if slashes or other characters are used in the label string.
877 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
878 can be specified now. The TEST key accepts an optional mode mask
879 TEST{0100}=="<is executable file>".
881 Scsi_id now supports a mode without expecting scsi-specific sysfs
882 entries to allow the extraction of cciss-device persistent properties.
888 In the future, we may see uuid's which are just simple character
889 strings (see the DDF Raid Specification). For that reason vol_id now
890 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
891 the creation of symlinks, the *_SAFE values ensure, that no control
892 or whitespace characters are used in the filename.
894 Possible users of libvolume_id, please use the volume_id_get_* functions.
895 The public struct will go away in a future release of the library.
901 Removal of useless extras/eventrecorder.sh.
911 The directory multiplexer for dev.d/ and hotplug.d are finally removed
912 from the udev package.
918 Symlinks can have priorities now, the priority is assigned to the device
919 and specified with OPTIONS="link_priority=100". Devices with higher
920 priorities overwrite the symlinks of devices with lower priorities.
921 If the device that currently owns the link, goes away, the symlink
922 will be removed, and recreated, pointing to the next device with the
923 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
924 more reliable, if multiple devices contain the same metadata and overwrite
927 The dasd_id program is removed from the udev tree, and dasdinfo, with the
928 needed rules, are part of the s390-tools now.
930 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
931 we may get the scsi sysfs mess fixed some day, and this will only catch
932 the devices we are looking for.
934 USB serial numbers for storage devices have the target:lun now appended,
935 to make it possibble to distinguish broken multi-lun devices with all
936 the same SCSI identifiers.
938 Note: The extra "run_directory" which searches and executes stuff in
939 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
940 with the next release. Make sure, that you don't use it anymore, or
941 provides your own implementation of that inefficient stuff.
942 We are tired of reports about a "slow udev", because these directories
943 contain stuff, that runs with _every_ event, instead of using rules,
944 that run programs only for the matching events.
954 DRIVER== will match only for devices that actually have a real
955 driver. DRIVERS== must be used, if parent devices should be
956 included in the match.
958 Libvolume_id's "linux_raid" detection needed another fix.
966 Add additional check to volume_id detection of via_raid, cause
967 some company decided to put a matching pattern all over the empty
968 storage area of their music players.
972 Fix path_id for SAS devices.
976 The udev daemon can be started with --debug-trace now, which will
977 execute all events serialized to get a chance to catch a possible
978 action that crashes the box.
980 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
981 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
982 are excluded from the warning. Referencing parent attributes directly
983 may break when something in the kernel driver model changes. Udev will
984 just find the attribute by walking up the parent chain.
986 Udevtrigger now sorts the list of devices depending on the device
987 dependency, so a "usb" device is triggered after the parent "pci"
992 Revert persistent-storage ata-serial '_' '-' replacement.
998 Udevtrigger can now filter the list of devices to be triggered. Matches
999 for subsystems or sysfs attributes can be specified.
1001 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1002 zero-sized files to avoid pointing to /sys and confuse broken tools which
1003 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1006 The rules and scripts to create udev rules for persistent network
1007 devices and optical drives are in the extras/rules_generator directory
1008 now. If you use something similar, please consider replacing your own
1009 version with this, to share the support effort. The rule_generator
1010 installs its own rules into /etc/udev/rules.d.
1012 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1013 the rule_generator depends on cdrom_id to be called in an earlier rule.
1019 Renaming of some key names (the old names still work):
1020 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1021 (The behavior of the key DRIVER will change soon in one of the next
1022 releases, to match only the event device, please switch to DRIVERS
1023 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1025 With the new key names, we have a more consistent and simpler scheme.
1026 We can match the properties of the event device only, with: KERNEL,
1027 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1028 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1029 longer mentioned in the man page and should be switched in the rule
1032 ATTR{file}="value" can be used now, to write to a sysfs file of the
1033 event device. Instead of:
1034 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1036 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1038 All the PHYSDEV* keys are deprecated and will be removed from a
1040 PHYDEVPATH - is the path of a parent device and should not be
1042 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1043 matched with SUBSYSTEMS==
1044 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1045 Newer kernels will have DRIVER in the environment,
1046 for older kernels udev puts in. Class device will
1047 no longer carry this property of a parent and
1048 DRIVERS== can be used to match such a parent value.
1049 Note that ENV{DRIVER} is only available for a few bus devices, where
1050 the driver is already bound at device event time. On coldplug, the
1051 events for a lot devices are already bound to a driver, and they will have
1052 that value set. But on hotplug, at the time the kernel creates the device,
1053 it can't know what driver may claim the device after that, therefore
1054 in most cases it will be empty.
1056 Failed events should now be re-triggered with:
1057 udevtrigger --retry-failed.
1058 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1059 files private to the udev tools. We may need to switch the current symlink
1060 target, cause some obviously broken tools try to scan all files in /dev
1061 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1062 million times. This takes ages on slow boxes.
1064 The udevinfo attribute walk (-a) now works with giving a device node
1065 name (-n) instead of a devpath (-p). The query now always works, also when
1066 no database file was created by udev.
1068 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1069 getpwnam() and getgrnam() now. One of the next releases will depend on
1070 fnmatch() and may use getopt_long().
1074 Bugfixes and small improvements.
1078 Fix path_id for recent kernels.
1084 Added support for swapping network interface names, by temporarily
1085 renaming the device and wait for the target name to become free.
1089 The built-in MODALIAS key and substitution is removed.
1093 The binary firmware helper is replaced by the usual simple
1094 shell script. Udevsend is removed from the tree.
1102 Some more keys require the correct use of '==' and '=' depending
1103 on the kind of operation beeing an assignment or a match. Rules
1104 with invalid operations are skipped and logged to syslog. Please
1105 test with udevtest if the parsing of your rules throws errors and
1106 fix possibly broken rules.
1110 Provide "udevsettle" to wait for all current udev events to finish.
1111 It also watches the current kernel netlink queue by comparing the
1112 even sequence number to make sure that there are no current pending
1113 events that have not already arrived in the daemon.
1117 Fix rule to skip persistent rules for removable IDE devices, which
1118 also skipped optical IDE drives.
1120 All *_id program are installed in /lib/udev/ by default now.
1122 No binary is stripped anymore as this should be done in the
1123 packaging process and not at build time.
1125 libvolume_id is provided as a shared library now and vol_id is
1126 linked against it. Also one of the next HAL versions will require
1127 this library, and the HAL build process will also require the
1128 header file to be installed. The copy of the same code in HAL will
1129 be removed to have only a single copy left on the system.
1133 Add persistent links for SCSI tapes. The rules file is renamed
1134 to 60-persistent-storage.rules.
1136 Create persistent path for usb devices. Can be used for all sorts
1137 of devices that can't be distinguished by other properties like
1138 multiple identical keyboards and mice connected to the same box.
1140 Provide "udevtrigger" program to request events on coldplug. The
1141 shell script is much too slow with thousends of devices.
1145 Fix persistent disk rules to exclude removable IDE drives.
1147 Warn if %e, $modalias or MODALIAS is used.
1151 Fix queue export, which wasn't correct for subsequent add/remove
1152 events for the same device.
1156 Fix cramfs detection on big endian.
1158 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1163 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1164 attributes were only checked at the parent device that matched the
1165 by BUS requested subsystem. Fix it to also look at the device we
1166 received the event for.
1168 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1173 Fix a bug where NAME="" would prevent RUN from beeing executed.
1175 RUN="/bin/program" does not longer automatically add the subsystem
1176 as the first parameter. This is from the days of /sbin/hotplug
1177 which is dead now and it's just confusing to need to add a space at
1178 the end of the program name to prevent this.
1179 If you use rules that need the subsystem as the first parameter,
1180 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1181 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1185 The udev man page has moved to udev(7) as it does not describe a command
1186 anymore. The programs udev, udevstart and udevsend are no longer installed
1187 by default and must be copied manually, if they should be installed or
1188 included in a package.
1190 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1191 the ignore rule was applied.
1193 More preparation for future sysfs changes. usb_id and scsi_id no longer
1194 depend on a magic order of devices in the /devices chain. Specific devices
1195 should be requested by their subsytem.
1197 This will always find the scsi parent device without depending on a specific
1199 dev = sysfs_device_get(devpath);
1200 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1202 The "device" link in the current sysfs layout will be automatically
1203 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1204 parent in the devpath. If a device is requested by it's symlink, like all
1205 class devices in the new sysfs layout will look like, it gets automatically
1206 resolved and substituted with the real devpath and not the symlink path.
1209 A similar logic must be applied to _all_ sysfs users, including
1210 scripts, that search along parent devices in sysfs. The explicit use of
1211 the "device" link must be avoided. With the future sysfs layout all
1212 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1213 back to the "class" or the "bus". The layout of the parent devices in
1214 /devices is not necessarily expected to be stable across kernel releases and
1215 searching for parents by their subsystem should make sysfs users tolerant
1216 for changed parent chains.
1220 Prepare udev to work with the experimental kernel patch, that moves
1221 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1223 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1224 moving the class devices to /sys/devices.
1226 Thanks again to Marco for help finding a hopefully nice compromise
1227 to make %b simpler and working again.
1231 Complete removal of libsysfs, replaced by simple helper functions
1232 which are much simpler and a bit faster. The udev daemon operatesentirely
1233 on event parameters and does not use sysfs for simple rules anymore.
1234 Please report any new bugs/problems, that may be caused by this big
1235 change. They will be fixed immediately.
1237 The enumeration format character '%e' is deprecated and will be
1238 removed sometimes from a future udev version. It never worked correctly
1239 outside of udevstart, so we can't use it with the new parallel
1240 coldplug. A simple enumeration is as useless as the devfs naming
1241 scheme, just get rid of both if you still use it.
1243 MODALIAS and $modalias is not needed and will be removed from one of
1244 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1245 the sysfs "modalias" value.
1247 Thanks a lot to Marco for all his help on finding and fixing bugs.
1251 Let scsi_id request libata drive serial numbers from page 0x80.
1253 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1254 added /dev/disk/by-name/* for device mapper device names.
1256 Removed %e from the man page. It never worked reliably outside
1257 of udevstart and udevstart is no longer recommended to use.
1261 Symlinks are now exported to the event environment. Hopefully it's no
1262 longer needed to run udevinfo from an event process, like it was
1263 mentioned on the hotplug list:
1264 UDEV [1134776873.702967] add@/block/sdb
1267 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1271 Fix a problem if udevsend is used as the hotplug handler and tries to use
1272 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1273 and this kind of problems will hopefully go away soon.
1277 All built-in logic to work around bad sysfs timing is removed with this
1278 version. The need to wait for sysfs files is almost fixed with a kernel
1279 version that doesn't work with this udev version anyway. Until we fix
1280 the timing of the "bus" link creation, the former integrated logic should
1281 be emulated by a rule placed before all other rules:
1282 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1284 The option "udev_db" does no longer exist. All udev state will be in
1285 /$udev_root/.udev/ now, there is no longer an option to set this
1287 If the init script or something else used this value, just depend on
1288 this hardcoded path. But remember _all_content_ of this directory is
1289 still private to udev and can change at any time.
1291 Default location for rule sripts and helper programs is now: /lib/udev/.
1292 Everything that is not useful on the commandline should go into this
1293 directory. Some of the helpers in the extras folder are installed there
1294 now. The rules need to be changed, to find the helpers there.
1296 Also /lib/udev/devices is recommended as a directory where packages or
1297 the user can place real device nodes, which get copied over to /dev at
1298 every boot. This should replace the various solutions with custom config
1301 Udevsend does no longer start the udev daemon. This must be done with
1302 the init script that prepares /dev on tmpfs and creates the initial nodes,
1303 before starting the daemon.
1307 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1310 The copy of klibc is removed. A systemwide installed version of klibc
1311 should be used to build a klibc udev now.
1315 NAME="" will not create any nodes, but execute RUN keys. To completely
1316 ignore an event the OPTION "ignore_device" should be used.
1318 After removal of the reorder queue, events with a TIMEOUT can be executed
1319 without any queuing now.
1323 Fixed bug in udevd, if inotify is not available. We depend on netlink
1324 uevents now, kernels without that event source will not work with that
1325 version of udev anymore.
1329 The rule parsing happens now in the daemon once at startup, all udev
1330 event processes inherit the already parsed rules from the daemon.
1331 It is shipped with SUSE10.0 and reduces heavily the system load at
1332 startup. The option to save precompiled rules and let the udev process
1333 pick the them up is removed, as it's no longer needed.
1335 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1336 device. Libsysfs is changed to "translate" the requested link into the
1337 real device path, as it would happen with the hotplug event. Otherwise
1338 device removal and the udev database will not work.
1340 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1343 A few improvements for vol_id, the filesytem probing code.
1347 Fix a stupid typo in extras/run_directory for "make install".
1349 scsi_id creates the temporary devnode now in /dev for usage with a
1350 non-writable /tmp directory.
1352 The uevent kernel socket buffer can carry app. 50.000 events now,
1353 let's see who can break this again. :)
1355 The upcoming kernel will have a new input driver core integration.
1356 Some class devices are now symlinks to the real device. libsysfs
1357 needs a fix for this to work correctly. Udevstart of older udev
1358 versions will _not_ create these devices!
1362 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1367 A bunch of mostly trivial bugfixes. From now on no node name or
1368 symlink name can contain any character than plain whitelisted ascii
1369 characters or validated utf8 byte-streams. This is needed for the
1370 /dev/disk/by-label/* links, because we import untrusted data and
1371 export it to the filesystem.
1375 More bugfixes. If udevd was started from the kernel, we don't
1376 have stdin/stdout/stderr, which broke the forked tools in some
1381 Bugfix. udevstart event ordering was broken for a long time.
1382 The new run_program() uncovered it, because /dev/null was not
1383 available while we try to run external programs.
1384 Now udevstart should create it before we run anything.
1388 Minor bugfixes and some distro rules updates. If you don't have the
1389 persistent disk rules in /dev/disk/by-*/* on your distro, just
1390 grab it from here. :)
1394 We can use socket communication now to pass events from udev to
1396 RUN+="socket:/org/freedesktop/hal/udev_event"
1397 will pass the whole udev event to the HAL daemon without the need
1398 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1402 Mostly bugfixes and see ChangeLog.
1404 The test for the existence of an environment value should be
1406 ENV{KEY}=="*" to ENV{KEY}=="?*"
1407 because "*" will not fail anymore, if the key does not exist or
1412 Bugfixes and a few tweaks described in the ChangeLog.
1416 Mostly a Bugfix release.
1418 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1419 timing with custom rules.
1423 We changed the internal rule storage format. Our large rule files took
1424 2 MB of RAM, with the change we are down to 99kB.
1426 If the device-node has been created with default name and no symlink or
1427 options are to remenber, it is not longer stored in the udevdb. HAL will
1428 need to be updated to work correctly with that change.
1430 To overrride optimization flags, OPTFLAGS may be used now.
1438 Major changes happened with this release. The goal is to take over the
1439 complete kernel-event handling and provide a more efficient way to dispatch
1440 kernel events. Replacing most of the current shell script logic and the
1441 kernel forked helper with a netlink-daemon and a rule-based event handling.
1443 o udevd listens to netlink events now. The first valid netlink event
1444 will make udevd ignore any message from udevsend that contains a
1445 SEQNUM, to avoid duplicate events. The forked events can be disabled
1447 echo "" > /proc/sys/kernel/hotplug
1448 For full support, the broken input-subsytem needs to be fixed, not to
1449 bypass the driver core.
1451 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1452 removed from udev itself and must be emulated by calling small
1453 helper binaries provided in the extras folder:
1454 make EXTRAS=extras/run_directory/
1455 will build udev_run_devd and udev_run_hotplugd, which can be called
1456 from a rule if needed:
1457 RUN+="/sbin/udev_run_hotplugd"
1458 The recommended way to handle this is to convert all the calls from
1459 the directories to explicit udev rules and get completely rid of the
1460 multiplexing. (To catch a ttyUSB event, you now no longer need to
1461 fork and exit 300 tty script instances you are not interested in, it
1462 is just one rule that matches exactly the device.)
1464 o udev handles now _all_ events not just events for class and block
1465 devices, this way it is possible to control the complete event
1466 behavior with udev rules. Especially useful for rules like:
1467 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1469 o As used in the modalias rule, udev supports now textual
1470 substitution placeholder along with the usual format chars. This
1471 needs to be documented, for now it's only visible in udev_rules_parse.c.
1473 o The rule keys support now more operations. This is documented in the
1474 man page. It is possible to add values to list-keys like the SYMLINK
1475 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1476 Also "final"-assignments are supported by using KEY:="value", which will
1477 prevent changing the key by any later rule.
1479 o kernel 2.6.12 has the "detached_state" attribute removed from
1480 sysfs, which was used to recognize sysfs population. We switched that
1481 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1482 Running this udev version on older kernels may cause a short delay for
1485 o To provide infrastructure for persistent device naming, the id programs:
1486 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1487 to export the probed data in environment key format:
1488 pim:~ # /sbin/ata_id --export /dev/hda
1489 ID_MODEL=HTS726060M9AT00
1490 ID_SERIAL=MRH401M4G6UM9B
1491 ID_REVISION=MH4OA6BA
1493 The following rules:
1494 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1495 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1498 kay@pim:~> tree /dev/disk
1501 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1502 | `-- IBM-Memory_Key -> ../../sda
1504 | |-- swap -> ../../hda1
1505 | |-- date -> ../../sda1
1506 | `-- home -> ../../hda3
1508 |-- 2E08712B0870F2E7 -> ../../hda3
1509 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1510 |-- E845-7A89 -> ../../sda1
1511 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1513 The IMPORT= operation will import these keys in the environment and make
1514 it available for later PROGRAM= and RUN= executed programs. The keys are
1515 also stored in the udevdb and can be queried from there with one of the
1518 o A few binaries are silently added to the repository, which can be used
1519 to replay kernel events from initramfs instead of using coldplug. udevd
1520 can be instructed now to queue-up events while the stored events from
1521 initramfs are filled into the udevd-queue. This code is still under
1522 development and there is no documentation now besides the code itself.
1523 The additional binaries get compiled, but are not installed by default.
1525 o There is also a temporary fix for a performance problem where too many
1526 events happen in parallel and every event needs to parse the rules.
1527 udev can now read precompiled rules stored on disk. This is likely to be
1528 replaced by a more elegant solution in a future udev version.
1532 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1533 Fix for libsysfs not to expect this file was added.
1537 All rules are applied now, but only the first matching rule with a NAME-key
1538 will be applied. All later rules with NAME-key are completely ignored. This
1539 way system supplied symlinks or permissions gets applied to user-defined
1543 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1544 to some rules, to keep the old behavior.
1546 The rules are read on "remove"-events too. That makes is possible to match
1547 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1548 instruct udev to ignore an event (OPTIONS="ignore_device").
1549 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1551 The new RUN-key supports rule-based execution of programs after device-node
1552 handling. This is meant as a general replacement for the dev.d/-directories
1553 to give fine grained control over the execution of programs.
1555 The %s{}-sysfs format char replacement values are searched at any of the
1556 devices in the device chain now, not only at the class-device.
1558 We support log priority levels now. The value udev_log in udev.conf is used
1559 to determine what is printed to syslog. This makes it possible to
1560 run a version with compiled-in debug messages in a production environment
1561 which is sometimes needed to find a bug.
1562 It is still possible to supress the inclusion of _any_ syslog usage with
1563 USE_LOG=false to create the smallest possible binaries if needed.
1564 The configured udev_log value can be overridden with the environment variable
1569 Possible use of a system-wide klibc:
1570 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1571 will link against an external klibc and our own version will be ignored.
1575 We support an unlimited count of symlinks now.
1577 If USE_STATIC=true is passed to a glibc build, we link statically and use
1578 a built-in userdb parser to resolve user and group names.
1580 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1581 we walk up the chain of physical devices to find a match.
1583 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1584 easy to skip certain attribute matches without composing rules with weird
1585 character class negations like:
1586 KERNEL="[!s][!c][!d]*"
1587 this can now be replaced with:
1589 The current simple '=' is still supported, and should work as it does today,
1590 but existing rules should be converted if possible, to be better readable.
1592 We have new ENV{}== key now, to match against a maximum of 5 environment
1595 udevstart is its own binary again, because we don't need co carry this araound
1596 with every forked event.