5 The udev daemon moved to /lib/udev/udevd. Non-systemd init systems
6 and non-dracut initramfs image generators need to change the init
7 scripts. Alternatively the udev build needs to move udevd back to
8 /sbin or create a symlink in /sbin, which is not done by default.
10 The path_id, usb_id, input_id tools are built-in commands now and
11 the stand-alone tools do not exist anymore. Static lists of file in
12 initramfs generators need to be updated. For testing, the commands
13 can still be executed standalone with 'udevadm test-builtin <cmd>'.
15 The fusectl filesystem is no longer mounted directly from udev.
16 Systemd systems will take care of mounting fusectl and configfs
17 now. Non-systemd systems need to ship their own rule if they
18 need these filesystems auto-mounted.
20 The long deprecated keys: SYSFS=, ID=, BUS= have been removed.
22 The support for 'udevadm trigger --type=failed, and the
23 RUN{fail_event_on_error} attribute was removed.
25 The udev control socket is now created in /run/udev/control
26 and no longer as an abstract namespace one.
28 The rules to create persistent network interface and cdrom link
29 rules automatically in /etc/udev/rules.d/ have been disabled by
30 default. Explicit configuration will be required for these use
31 cases, udev will no longer try to write any persistent system
32 configuration from a device hotplug path.
38 The udev-acl extra is no longer enabled by default now. To enable it,
39 --enable-udev_acl needs to be given at ./configure time. On systemd
40 systems, the udev-acl rules prevent it from running as the functionality
47 Udev now enables kernel media-presence polling if available. Part
48 of udisks optical drive tray-handling moved to cdrom_id: The tray
49 is locked as soon as a media is detected to enable the receiving
50 of media-eject-request events. Media-eject-request events will
53 Libudev enumerate is now able to enumerate a subtree of a given
56 The mobile-action-modeswitch modeswitch tool was deleted. The
57 functionality is provided by usb_modeswitch now.
63 The systemd service files require systemd version 28. The systemd
64 socket activation make it possible now to start 'udevd' and 'udevadm
69 Fix bug in control message handling, which can lead to a failing
70 udevadm control --exit. Thanks to Jürg Billeter for help tracking
77 We require at least Linux kernel 2.6.32 now. Some platforms might
78 require a later kernel that supports accept4() and similar, or
79 need to backport the trivial syscall wiring to the older kernels.
81 The hid2hci tool moved to the bluez package and was removed.
83 Many of the extras can be --enable/--disabled at ./configure
84 time. The --disable-extras option was removed. Some extras have
85 been disabled by default. The current options and their defaults
86 can be checked with './configure --help'.
92 Udev logs a warning now if /run is not writable at udevd
93 startup. It will still fall back to /dev/.udev, but this is
96 The running udev daemon can now cleanly shut down with:
97 udevadm control --exit
99 Udev in initramfs should clean the state of the udev database
100 with: udevadm info --cleanup-db which will remove all state left
101 behind from events/rules in initramfs. If initramfs uses
102 --cleanup-db and device-mapper/LVM, the rules in initramfs need
103 to add OPTIONS+="db_persist" for all dm devices. This will
104 prevent removal of the udev database for these devices.
106 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
107 120 seconds per process. If that timeout is reached the spawned
108 process will be killed. The event timeout can be overwritten with
111 If systemd is used, udev gets now activated by netlink data.
112 Systemd will bind the netlink socket which will buffer all data.
113 If needed, such setup allows a seemless update of the udev daemon,
114 where no event can be lost during a udevd update/restart.
115 Packages need to make sure to: systemctl stop udev.socket udev.service
116 or 'mask' udev.service during the upgrade to prevent any unwanted
117 auto-spawning of udevd.
118 This version of udev conflicts with systemd version below 25. The
119 unchanged service files will not wirk correctly.
125 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
126 /run mountpoint is supposed to be a tmpfs mounted during early boot,
127 available and writable to for all tools at any time during bootup,
128 it replaces /var/run/, which should become a symlink some day.
130 If /run does not exist, or is not writable, udev will fall back using
133 On systemd systems with initramfs and LVM used, packagers must
134 make sure, that the systemd and initramfs versions match. The initramfs
135 needs to create the /run mountpoint for udev to store the data, and
136 mount this tmpfs to /run in the rootfs, so the that the udev database
137 is preserved for the udev version started in the rootfs.
139 The command 'udevadm info --convert-db' is gone. The udev daemon
140 itself, at startup, converts any old database version if necessary.
142 The systemd services files have been reorganized. The udev control
143 socket is bound by systemd and passed to the started udev daemon.
144 The udev-settle.service is no longer active by default. Services which
145 can not handle hotplug setups properly need to actively pull it in, to
146 act like a barrier. Alternatively the settle service can be unconditionally
147 'systemctl'enabled, and act like a barrier for basic.target.
149 The fstab_import callout is no longer built or installed. Udev
150 should not be used to mount, does not watch changes to fstab, and
151 should not mirror fstab values in the udev database.
157 New and updated keymaps.
163 The udev database has changed, After installation of a new udev
164 version, 'udevadm info --convert-db' should be called, to let the new
165 udev/libudev version read the already stored data.
167 udevadm now supports quoting of property values, and prefixing of
169 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
172 MY_DEVNAME='/dev/sda'
176 libudev now supports:
177 udev_device_get_is_initialized()
178 udev_enumerate_add_match_is_initialized()
179 to be able to skip devices the kernel has created , but udev has
182 libudev now supports:
183 udev_device_get_usec_since_initialized()
184 to retrieve the "age" of a udev device record.
186 GUdev supports a more generic GUdevEnumerator class, udev TAG
187 handling, device initialization and timestamp now.
189 The counterpart of /sys/dev/{char,block}/$major:$minor,
190 /dev/{char,block}/$major:$minor symlinks are now unconditionally
191 created, even when no rule files exist.
193 New and updated keymaps.
199 GUdev moved from /usr to /.
209 Persistent network naming rules are disabled inside of Qemu/KVM now.
211 New and updated keymaps.
213 Udev gets unconditionally enabled on systemd installations now. There
214 is no longer the need to to run 'systemctl enable udev.service'.
228 New and fixed keymaps.
230 Install systemd service files if applicable.
236 All distribution specific rules are removed from the udev source tree,
237 most of them are no longer needed. The Gentoo rules which allow to support
238 older kernel versions, which are not covered by the default rules anymore
239 has moved to rules/misc/30-kernel-compat.rules.
245 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
246 was removed from udevd.
248 Udevd now checks the kernel commandline for the following variables:
249 udev.log-priority=<syslog priority>
250 udev.children-max=<maximum number of workers>
251 udev.exec-delay=<seconds to delay the execution of RUN=>
252 to help debuging coldplug setups where the loading of a kernel
253 module crashes the system.
255 The subdirectory in the source tree rules/packages has been renamed to
256 rules/arch, anc contains only architecture specific rules now.
266 Now the udev daemon itself, does on startup:
267 - copy the content of /lib/udev/devices to /dev
268 - create the standard symlinks like /dev/std{in,out,err},
269 /dev/core, /dev/fd, ...
270 - use static node information provided by kernel modules
271 and creates these nodes to allow module on-demand loading
272 - possibly apply permissions to all ststic nodes from udev
273 rules which are annotated to match a static node
275 The default mode for a device node is 0600 now to match the kernel
276 created devtmpfs defaults. If GROUP= is specified and no MODE= is
277 given the default will be 0660.
283 Udev now gradually starts to pass control over the primary device nodes
284 and their names to the kernel, and will in the end only manage the
285 permissions of the node, and possibly create additional symlinks.
286 As a first step NAME="" will be ignored, and NAME= setings with names
287 other than the kernel provided name will result in a logged warning.
288 Kernels that don't provide device names, or devtmpfs is not used, will
289 still work as they did before, but it is strongly recommended to use
290 only the same names for the primary device node as the recent kernel
291 provides for all devices.
295 Fix broken firmware loader search path.
301 "udevadm trigger" defaults to "change" events now instead of "add"
302 events. The "udev boot script" might need to add "--action=add" to
303 the trigger command if not already there, in case the initial coldplug
304 events are expected as "add" events.
306 The option "all_partitons" was removed from udev. This should not be
307 needed for usual hardware. Udev can not safely make assumptions
308 about non-existing partition major/minor numbers, and therefore no
309 longer provide this unreliable and unsafe option.
311 The option "ignore_remove" was removed from udev. With devtmpfs
312 udev passed control over device nodes to the kernel. This option
313 should not be needed, or can not work as advertised. Neither
314 udev nor the kernel will remove device nodes which are copied from
315 the /lib/udev/devices/ directory.
317 All "add|change" matches are replaced by "!remove" in the rules and
318 in the udev logic. All types of events will update possible symlinks
319 and permissions, only "remove" is handled special now.
321 The modem modeswitch extra was removed and the external usb_modeswitch
322 program should be used instead.
324 New and fixed keymaps.
334 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
335 depend on the current sysfs layout and the information not available in the
336 deprecated layout. All remaining support for the deprecated sysfs layout is
341 Fix for a possible endless loop in the new input_id program.
347 The option "ignore_device" does no longer exist. There is no way to
348 ignore an event, as libudev events can not be suppressed by rules.
349 It only prevented RUN keys from being executed, which results in an
350 inconsistent behavior in current setups.
352 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
353 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
356 The support for the deprecated IDE devices has been removed from the
357 default set of rules. Distros who still care about non-libata drivers
358 need to add the rules to the compat rules file.
360 The ID_CLASS property on input devices has been replaced by the more accurate
361 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
362 determined by the new "input_id" prober now. Some devices, such as touchpads,
363 can have several classes. So if you previously had custom udev rules which e. g.
364 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
365 ENV{ID_INPUT_KEYBOARD}=="?*".
371 To support DEVPATH strings larger than the maximum file name length, the
372 private udev database format has changed. If some software still reads the
373 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
374 Please do not port anything to the new format again, everything in /dev/.udev
375 is and always was private to udev, and may and will change any time without
378 Multiple devices claiming the same names in /dev are limited to symlinks
379 only now. Mixing identical symlink names and node names is not supported.
380 This reduces the amount of data in the database significantly.
382 NAME="%k" causes a warning now. It's is and always was completely superfluous.
383 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
386 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
387 if they are not the default. To support older kernels, the NAME= rules need to
388 be added to the compat rules file.
390 Symlinks to udevadm with the old command names are no longer resolved to
391 the udevadm commands.
393 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
396 The option "last_rule" does no longer exist. Its use breaks too many
397 things which expect to be run from independent later rules, and is an idication
398 that something needs to be fixed properly instead.
400 The gudev API is no longer marked as experimental,
401 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
402 is enabled by default now. Various projects already depend on introspection
403 information to bind dynamic languages to the gudev interfaces.
409 The udevadm trigger "--retry-failed" option, which is replaced since quite
410 a while by "--type=failed" is removed.
412 The failed tracking was not working at all for a few releases. The RUN
413 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
414 default is not to track any failing RUN executions.
416 New keymaps, new modem, hid2hci updated.
420 Fix possible crash in udevd when worker processes are busy, rules are
421 changed at the same time, and workers get killed to reload the rules.
427 Properties set with ENV{.FOO}="bar" are marked private by starting the
428 name with a '.'. They will not be stored in the database, and not be
429 exported with the event.
431 Firmware files are looked up in:
432 /lib/firmware/updates/$(uname -r)
433 /lib/firmware/updates
434 /lib/firmware/$(uname -r)
438 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
439 ata_id, instead of scsi_id, is the default tool now for ATA devices.
445 The configure options have changed because another library needs to be
446 installed in a different location. Instead of exec_prefix and udev_prefix,
447 libdir, rootlibdir and libexecdir are used. The Details are explained in
450 Event processes now get re-used after they handled an event. This reduces
451 the number of forks and the pressure on the CPU significantly, because
452 cloned event processes no longer cause page faults in the main daemon.
453 After the events have settled, a few worker processes stay around for
454 future events, all others get cleaned up.
456 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
457 Also inotify support is mandatory now to run udev.
459 The format of the queue exported by the udev damon has changed. There is
460 no longer a /dev/.udev/queue/ directory. The current event queue can be
461 accessed with udevadm settle and libudedv.
463 Libudev does not have the unstable API header anymore. From now on,
464 incompatible changes will be handled by bumping the library major version.
466 To build udev from the git tree gtk-doc is needed now. The tarballs will
467 build without it and contain the pre-built documentation. An online copy
469 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
471 The tools from the udev-extras repository have been merged into the main
472 udev repository. Some of the extras have larger external dependencies, and
473 they can be disabled with the configure switch --disable-extras.
479 The program vol_id and the library libvolume_id are removed from the
480 repository. Libvolume_id is merged with libblkid from the util-linux-ng
481 package. Persistent disk links for label and uuid depend on the
482 util-linux-ng version (2.15) of blkid now. Older versions of blkid
483 can not be used with udev.
485 Libudev allows to subscribe to udev events. To prevent unwanted messages
486 to be delivered, and waking up the subscribing process, a filter can be
487 installed, to drop messages inside a kernel socket filter. The filters
488 match on the <subsytem>:<devtype> properties of the device.
489 This is part of the ongoing effort to replace HAL, and switch current
490 users over to directly use libudev.
491 Libudev is still marked as experimental, and its interface might
492 eventually change if needed, but no major changes of the currently exported
493 interface are expected anymore, and a first stable release should happen
496 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
497 is not supported since while and udevd will log an error message at
498 startup. It should still be able to boot-up, but advanced rules and system
499 services which depend on the information not available in the old sysfs
500 format will fail to work correctly.
502 DVB device naming is supplied by the kernel now. In case older kernels
503 need to be supported, the old shell script should be added to a compat
510 The processed udev events get send back to the netlink socket. Libudev
511 provides access to these events. This is work-in-progress, to replace
512 the DeviceKit daemon functionality directly with libudev. There are
513 upcoming kernel changes to allow non-root users to subcribe to these
520 "udevadm settle" now optionally accepts a range of events to wait for,
521 instead of waiting for "all" events.
527 The installed watch for block device metadata changes is now removed
528 during event hadling, because some (broken) tools may be called from udev
529 rules and (wrongly) open the device with write access. After the finished
530 event handling the watch is restored.
536 Device nodes can be watched for changes with inotify with OPTIONS="watch".
537 If closed after being opened for writing, a "change" uevent will occur.
538 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
544 The udevadm test command has no longer a --force option, nodes and symlinks
545 are always updated with a test run now.
547 The udevd daemon can be started with --resolve-names=never to avoid all user
548 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
549 lookup user and groups every time events are handled.
555 We are currently merging the Ubuntu rules in the udev default rules,
556 and get one step closer to provide a common Linux /dev setup, regarding
557 device names, symlinks, and default device permissions. On udev startup,
558 we now expect the following groups to be resolvable to their ids with
560 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
561 LDAP setups need to make sure, that these groups are always resolvable at
562 bootup, with only the rootfs mounted, and without network access available.
564 Some systems may need to add some new, currently not used groups, or need
565 to add some users to new groups, but the cost of this change is minimal,
566 compared to the pain the current, rather random, differences between the
567 various distributions cause for upstream projects and third-party vendors.
569 In general, "normal" users who log into a machine should never be a member
570 of any such group, but the device-access should be managed by dynamic ACLs,
571 which get added and removed for the specific users on login/logout and
572 session activity/inactivity. These groups are only provided for custom setups,
573 and mainly system services, to allow proper privilege separation.
574 A video-streaming daemon uid would be a member of "audio" and "video", to get
575 access to the sound and video devices, but no "normal" user should ever belong
576 to the "audio" group, because he could listen to the built-in microphone with
577 any ssh-session established from the other side of the world.
579 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
580 which do not depend on the kernel device name. As usual, unique
581 devices - only a single one per product connected, or a real
582 USB serial number in the device - are always found with the same
583 name in the by-id/ directory.
584 Completely identical devices may overwrite their names in by-id/
585 and can only be found reliably in the by-path/ directory. Devices
586 specified by by-path/ must not change their connection, like the
587 USB port number they are plugged in, to keep their name.
589 To support some advanced features, Linux 2.6.22 is the oldest supported
590 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
591 supported. Older kernels should still work, and devices nodes should be
592 reliably created, but some rules and libudev will not work correctly because
593 the old kernels do not provide the expected information or interfaces.
599 Fix for a possible segfault while swapping network interface names in udev
606 The group "video" is part of the default rules now.
610 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
611 block devices in some cases. No common distro uses this option anymore,
612 and we do not get enough testing for this and recent udev versions. If
613 this option is not needed to run some old distro with a new kernel,
614 it should be disabled in the kernel config.
616 Bugfix for the $links substitution variable, which may crash if no links
617 are created. This should not happen in usual setups because we always
618 create /dev/{block,char}/ links.
620 The strings of the parsed rules, which are kept in memory, no longer
621 contain duplicate entries, or duplicate tails of strings. This, and the
622 new rules parsing/matching code reduces the total in-memory size of
623 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
626 The export of DEVTYPE=disk/partition got removed from the default
627 rules. This value is available from the kernel. The pnp shell script
628 modprobe hack is removed from the default rules. ACPI devices have _proper_
629 modalias support and take care of the same functionality.
630 Installations which support old kernels, but install current default
631 udev rules may want to add that to the compat rules file.
633 Libvolume_id now always probes for all known filesystems, and does not
634 stop at the first match. Some filesystems are marked as "exclusive probe",
635 and if any other filesytem type matches at the same time, libvolume_id
636 will, by default, not return any probing result. This is intended to prevent
637 mis-detection with conflicting left-over signatures found from earlier
638 file system formats. That way, we no longer depend on the probe-order
639 in case of multiple competing signatures. In some setups the kernel allows
640 to mount a volume with just the old filesystem signature still in place.
641 This may damage the new filesystem and cause data-loss, just by mounting
642 it. Because volume_id can not decide which one the correct signature is,
643 the wrong signatures need to be removed manually from the volume, or the
644 volume needs to be reformatted, to enable filesystem detection and possible
649 Fix segfault if compiled without optimization and dbg() does not get
650 compiled out and uses variables which are not available.
654 Bugfixes. (And maybe new bugs. :))
656 The rule matching engine got converted from a rule list to a token
657 array which reduced the in-memory rules representation of a full
658 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
659 Limits like 5 ENV and ATTR matches, and one single instance for most
660 other keys per rule are gone.
662 The NAME assignment is no longer special cased. If later rules assign
663 a NAME value again, the former value will be overwritten. As usual
664 for most other keys, the NAME value can be protected by doing a final
665 assignment with NAME:="<value>".
667 All udev code now uses libudev, which is also exported. The library
668 is still under development, marked as experimental, and its interface
669 may change as long as the DeviceKit integration is not finished.
671 Many thanks to Alan Jenkins for his continuous help, and finding and
672 optimizing some of the computing expensive parts.
678 Kernel devices and device nodes are connected now by reverse indizes in
679 /sys and /dev. A device number retrieved by a stat() or similar, the
680 kernel device directory can be found by looking up:
681 /sys/dev/{block,char}/<maj>:<min>
682 and the device node of the same device by looking up:
683 /dev/{block,char}/<maj>:<min>
687 Fix recently introduced bug, which caused a compilation without large
688 file support, where vol_id does not recognize raid signatures at the end
691 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
692 Seems some kernel versions prevent the creation of the ieee-* links,
693 so people used the scsi-* link which disappeared now.
695 More libudev work. Almost all udevadm functionality comes from libudev
698 udevadm trigger has a new option --type, which allows to trigger events
699 for "devices", for "subsystems", or "failed" devices. The old option
700 --retry-failed" still works, but is no longer mentioned in the man page.
706 The udevadm info --device-id-of-file= output has changed to use
707 the obvious format. Possible current users should use the --export
708 option which is not affected.
710 The old udev commands symlinks to udevadm are not installed, if
711 these symlinks are used, a warning is printed.
717 Optical drive's media is no longer probed for raid signatures,
718 reading the end of the device causes some devices to malfunction.
719 Also the offset of the last session found is used now to probe
722 The volume_id library got a major version number update to 1,
723 some deprecated functions are removed.
725 A shared library "libudev" gets installed now to provide access
726 to udev device information. DeviceKit, the successor of HAL, will
727 need this library to access the udev database and search sysfs for
729 The library is currently in an experimental state, also the API is
730 expected to change, as long as the DeviceKit integration is not
735 We use ./configure now. See INSTALL for details. Current
738 "/usr" - prefix for man pages, include files
740 "" - the root filesystem, prefix for libs and binaries
744 "lib" - directory name for libraries, not a path name
745 multilib 64bit systems may use "lib64" instead of "lib"
747 compile-in verbose debug messages
749 disable all logging and compile-out all log strings
751 link against SELInux libraries, to set the expected context
754 In the default rules, the group "disk" gets permissions 0660 instead
755 of 0640. One small step closer to unify distro rules. Some day, all
756 distros hopefully end up with the same set of rules.
758 No symlinks to udevadm are installed anymore, if they are still needed,
759 they should be provided by the package.
765 Default udev rules, which are not supposed to be edited by the user, should
766 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
767 the udev package and will be replaced with an update. Udev will pick up rule
769 /lib/udev/rules.d/ - default installed rules
770 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
771 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
772 It does not matter in which directory a rule file lives, all files are sorted
775 To help creating /dev/root, we have now:
776 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
779 In case the current --device-id-of-file is already used, please switch to
780 the --export format version, it saves the output parsing and the old
781 format will be changed to use ':' as a separator, like the format in the
786 Fix cdrom_id to properly recognize blank media.
792 Tape drive id-data is queried from /dev/bsg/* instead of the tape
793 nodes. This avoids rewinding tapes on open().
799 The symlinks udevcontrol and udevtrigger are no longer installed by
802 The scsi_id program does not depend on sysfs anymore. It can speak
803 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
804 data, which should solve some old problems with tape devices, where
805 we better do not open all tape device nodes to identify the device.
811 The cdrom_id program is replaced by an advanced version, which can
812 detect most common device types, and also properties of the inserted
813 media. This is part of moving some basic functionality from HAL into
814 udev (and the kernel).
820 The last WAIT_FOR_SYSFS rule is removed from the default rules.
822 The symlinks to udevadm for the debugging tools: udevmonitor and
823 udevtest are no longer created.
825 The symlinks to the udevadm man page for the old tool names are
828 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
829 should be prefixed with '@' to indicate that the path is not a
840 Udevstart is removed from the tree, it did not get installed for
841 a long time now, and is long replaced by trigger and settle.
847 All udev tools are merged into a single binary called udevadm.
848 The old names of the tools are built-in commands in udevadm now.
849 Symlinks to udevadm, with the names of the old tools, provide
850 the same functionality as the standalone tools. There is also
851 only a single udevadm.8 man page left for all tools.
853 Tools like mkinitramfs should be checked, if they need to include
854 udevadm in the list of files.
864 The etc/udev/rules.d/ directory now contains a default set of basic
865 udev rules. This initial version is the result of a rules file merge
866 of Fedora and openSUSE. For these both distros only a few specific
867 rules are left in their own file, named after the distro. Rules which
868 are optionally installed, because they are only valid for a specific
869 architecture, or rules for subsystems which are not always used are
870 in etc/udev/packages/.
876 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
877 actions by dynamically created rules.
879 SYMLINK=="<value>" matches agains the entries in the list of
880 currently defined symlinks. The links are not created in the
881 filesystem at that point in time, but the values can be matched.
883 RUN{ignore_error}+="<program>" will ignore any exit code from the
884 program and not record as a failed event.
890 Final merge of patches/features from the Ubuntu package.
896 Control characters in filesystem label strings are no longer silenty
897 removed, but hex-encoded, to be able to uniquely identify the device
898 by its symlink in /dev/disk/by-label/.
899 If libvolume_id is used by mount(8), LABEL= will work as expected,
900 if slashes or other characters are used in the label string.
902 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
903 can be specified now. The TEST key accepts an optional mode mask
904 TEST{0100}=="<is executable file>".
906 Scsi_id now supports a mode without expecting scsi-specific sysfs
907 entries to allow the extraction of cciss-device persistent properties.
913 In the future, we may see uuid's which are just simple character
914 strings (see the DDF Raid Specification). For that reason vol_id now
915 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
916 the creation of symlinks, the *_SAFE values ensure, that no control
917 or whitespace characters are used in the filename.
919 Possible users of libvolume_id, please use the volume_id_get_* functions.
920 The public struct will go away in a future release of the library.
926 Removal of useless extras/eventrecorder.sh.
936 The directory multiplexer for dev.d/ and hotplug.d are finally removed
937 from the udev package.
943 Symlinks can have priorities now, the priority is assigned to the device
944 and specified with OPTIONS="link_priority=100". Devices with higher
945 priorities overwrite the symlinks of devices with lower priorities.
946 If the device that currently owns the link, goes away, the symlink
947 will be removed, and recreated, pointing to the next device with the
948 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
949 more reliable, if multiple devices contain the same metadata and overwrite
952 The dasd_id program is removed from the udev tree, and dasdinfo, with the
953 needed rules, are part of the s390-tools now.
955 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
956 we may get the scsi sysfs mess fixed some day, and this will only catch
957 the devices we are looking for.
959 USB serial numbers for storage devices have the target:lun now appended,
960 to make it possibble to distinguish broken multi-lun devices with all
961 the same SCSI identifiers.
963 Note: The extra "run_directory" which searches and executes stuff in
964 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
965 with the next release. Make sure, that you don't use it anymore, or
966 provides your own implementation of that inefficient stuff.
967 We are tired of reports about a "slow udev", because these directories
968 contain stuff, that runs with _every_ event, instead of using rules,
969 that run programs only for the matching events.
979 DRIVER== will match only for devices that actually have a real
980 driver. DRIVERS== must be used, if parent devices should be
981 included in the match.
983 Libvolume_id's "linux_raid" detection needed another fix.
991 Add additional check to volume_id detection of via_raid, cause
992 some company decided to put a matching pattern all over the empty
993 storage area of their music players.
997 Fix path_id for SAS devices.
1001 The udev daemon can be started with --debug-trace now, which will
1002 execute all events serialized to get a chance to catch a possible
1003 action that crashes the box.
1005 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
1006 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
1007 are excluded from the warning. Referencing parent attributes directly
1008 may break when something in the kernel driver model changes. Udev will
1009 just find the attribute by walking up the parent chain.
1011 Udevtrigger now sorts the list of devices depending on the device
1012 dependency, so a "usb" device is triggered after the parent "pci"
1017 Revert persistent-storage ata-serial '_' '-' replacement.
1023 Udevtrigger can now filter the list of devices to be triggered. Matches
1024 for subsystems or sysfs attributes can be specified.
1026 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1027 zero-sized files to avoid pointing to /sys and confuse broken tools which
1028 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1031 The rules and scripts to create udev rules for persistent network
1032 devices and optical drives are in the extras/rules_generator directory
1033 now. If you use something similar, please consider replacing your own
1034 version with this, to share the support effort. The rule_generator
1035 installs its own rules into /etc/udev/rules.d.
1037 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1038 the rule_generator depends on cdrom_id to be called in an earlier rule.
1044 Renaming of some key names (the old names still work):
1045 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1046 (The behavior of the key DRIVER will change soon in one of the next
1047 releases, to match only the event device, please switch to DRIVERS
1048 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1050 With the new key names, we have a more consistent and simpler scheme.
1051 We can match the properties of the event device only, with: KERNEL,
1052 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1053 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1054 longer mentioned in the man page and should be switched in the rule
1057 ATTR{file}="value" can be used now, to write to a sysfs file of the
1058 event device. Instead of:
1059 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1061 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1063 All the PHYSDEV* keys are deprecated and will be removed from a
1065 PHYDEVPATH - is the path of a parent device and should not be
1067 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1068 matched with SUBSYSTEMS==
1069 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1070 Newer kernels will have DRIVER in the environment,
1071 for older kernels udev puts in. Class device will
1072 no longer carry this property of a parent and
1073 DRIVERS== can be used to match such a parent value.
1074 Note that ENV{DRIVER} is only available for a few bus devices, where
1075 the driver is already bound at device event time. On coldplug, the
1076 events for a lot devices are already bound to a driver, and they will have
1077 that value set. But on hotplug, at the time the kernel creates the device,
1078 it can't know what driver may claim the device after that, therefore
1079 in most cases it will be empty.
1081 Failed events should now be re-triggered with:
1082 udevtrigger --retry-failed.
1083 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1084 files private to the udev tools. We may need to switch the current symlink
1085 target, cause some obviously broken tools try to scan all files in /dev
1086 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1087 million times. This takes ages on slow boxes.
1089 The udevinfo attribute walk (-a) now works with giving a device node
1090 name (-n) instead of a devpath (-p). The query now always works, also when
1091 no database file was created by udev.
1093 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1094 getpwnam() and getgrnam() now. One of the next releases will depend on
1095 fnmatch() and may use getopt_long().
1099 Bugfixes and small improvements.
1103 Fix path_id for recent kernels.
1109 Added support for swapping network interface names, by temporarily
1110 renaming the device and wait for the target name to become free.
1114 The built-in MODALIAS key and substitution is removed.
1118 The binary firmware helper is replaced by the usual simple
1119 shell script. Udevsend is removed from the tree.
1127 Some more keys require the correct use of '==' and '=' depending
1128 on the kind of operation beeing an assignment or a match. Rules
1129 with invalid operations are skipped and logged to syslog. Please
1130 test with udevtest if the parsing of your rules throws errors and
1131 fix possibly broken rules.
1135 Provide "udevsettle" to wait for all current udev events to finish.
1136 It also watches the current kernel netlink queue by comparing the
1137 even sequence number to make sure that there are no current pending
1138 events that have not already arrived in the daemon.
1142 Fix rule to skip persistent rules for removable IDE devices, which
1143 also skipped optical IDE drives.
1145 All *_id program are installed in /lib/udev/ by default now.
1147 No binary is stripped anymore as this should be done in the
1148 packaging process and not at build time.
1150 libvolume_id is provided as a shared library now and vol_id is
1151 linked against it. Also one of the next HAL versions will require
1152 this library, and the HAL build process will also require the
1153 header file to be installed. The copy of the same code in HAL will
1154 be removed to have only a single copy left on the system.
1158 Add persistent links for SCSI tapes. The rules file is renamed
1159 to 60-persistent-storage.rules.
1161 Create persistent path for usb devices. Can be used for all sorts
1162 of devices that can't be distinguished by other properties like
1163 multiple identical keyboards and mice connected to the same box.
1165 Provide "udevtrigger" program to request events on coldplug. The
1166 shell script is much too slow with thousends of devices.
1170 Fix persistent disk rules to exclude removable IDE drives.
1172 Warn if %e, $modalias or MODALIAS is used.
1176 Fix queue export, which wasn't correct for subsequent add/remove
1177 events for the same device.
1181 Fix cramfs detection on big endian.
1183 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1188 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1189 attributes were only checked at the parent device that matched the
1190 by BUS requested subsystem. Fix it to also look at the device we
1191 received the event for.
1193 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1198 Fix a bug where NAME="" would prevent RUN from beeing executed.
1200 RUN="/bin/program" does not longer automatically add the subsystem
1201 as the first parameter. This is from the days of /sbin/hotplug
1202 which is dead now and it's just confusing to need to add a space at
1203 the end of the program name to prevent this.
1204 If you use rules that need the subsystem as the first parameter,
1205 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1206 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1210 The udev man page has moved to udev(7) as it does not describe a command
1211 anymore. The programs udev, udevstart and udevsend are no longer installed
1212 by default and must be copied manually, if they should be installed or
1213 included in a package.
1215 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1216 the ignore rule was applied.
1218 More preparation for future sysfs changes. usb_id and scsi_id no longer
1219 depend on a magic order of devices in the /devices chain. Specific devices
1220 should be requested by their subsytem.
1222 This will always find the scsi parent device without depending on a specific
1224 dev = sysfs_device_get(devpath);
1225 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1227 The "device" link in the current sysfs layout will be automatically
1228 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1229 parent in the devpath. If a device is requested by it's symlink, like all
1230 class devices in the new sysfs layout will look like, it gets automatically
1231 resolved and substituted with the real devpath and not the symlink path.
1234 A similar logic must be applied to _all_ sysfs users, including
1235 scripts, that search along parent devices in sysfs. The explicit use of
1236 the "device" link must be avoided. With the future sysfs layout all
1237 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1238 back to the "class" or the "bus". The layout of the parent devices in
1239 /devices is not necessarily expected to be stable across kernel releases and
1240 searching for parents by their subsystem should make sysfs users tolerant
1241 for changed parent chains.
1245 Prepare udev to work with the experimental kernel patch, that moves
1246 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1248 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1249 moving the class devices to /sys/devices.
1251 Thanks again to Marco for help finding a hopefully nice compromise
1252 to make %b simpler and working again.
1256 Complete removal of libsysfs, replaced by simple helper functions
1257 which are much simpler and a bit faster. The udev daemon operatesentirely
1258 on event parameters and does not use sysfs for simple rules anymore.
1259 Please report any new bugs/problems, that may be caused by this big
1260 change. They will be fixed immediately.
1262 The enumeration format character '%e' is deprecated and will be
1263 removed sometimes from a future udev version. It never worked correctly
1264 outside of udevstart, so we can't use it with the new parallel
1265 coldplug. A simple enumeration is as useless as the devfs naming
1266 scheme, just get rid of both if you still use it.
1268 MODALIAS and $modalias is not needed and will be removed from one of
1269 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1270 the sysfs "modalias" value.
1272 Thanks a lot to Marco for all his help on finding and fixing bugs.
1276 Let scsi_id request libata drive serial numbers from page 0x80.
1278 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1279 added /dev/disk/by-name/* for device mapper device names.
1281 Removed %e from the man page. It never worked reliably outside
1282 of udevstart and udevstart is no longer recommended to use.
1286 Symlinks are now exported to the event environment. Hopefully it's no
1287 longer needed to run udevinfo from an event process, like it was
1288 mentioned on the hotplug list:
1289 UDEV [1134776873.702967] add@/block/sdb
1292 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1296 Fix a problem if udevsend is used as the hotplug handler and tries to use
1297 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1298 and this kind of problems will hopefully go away soon.
1302 All built-in logic to work around bad sysfs timing is removed with this
1303 version. The need to wait for sysfs files is almost fixed with a kernel
1304 version that doesn't work with this udev version anyway. Until we fix
1305 the timing of the "bus" link creation, the former integrated logic should
1306 be emulated by a rule placed before all other rules:
1307 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1309 The option "udev_db" does no longer exist. All udev state will be in
1310 /$udev_root/.udev/ now, there is no longer an option to set this
1312 If the init script or something else used this value, just depend on
1313 this hardcoded path. But remember _all_content_ of this directory is
1314 still private to udev and can change at any time.
1316 Default location for rule sripts and helper programs is now: /lib/udev/.
1317 Everything that is not useful on the commandline should go into this
1318 directory. Some of the helpers in the extras folder are installed there
1319 now. The rules need to be changed, to find the helpers there.
1321 Also /lib/udev/devices is recommended as a directory where packages or
1322 the user can place real device nodes, which get copied over to /dev at
1323 every boot. This should replace the various solutions with custom config
1326 Udevsend does no longer start the udev daemon. This must be done with
1327 the init script that prepares /dev on tmpfs and creates the initial nodes,
1328 before starting the daemon.
1332 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1335 The copy of klibc is removed. A systemwide installed version of klibc
1336 should be used to build a klibc udev now.
1340 NAME="" will not create any nodes, but execute RUN keys. To completely
1341 ignore an event the OPTION "ignore_device" should be used.
1343 After removal of the reorder queue, events with a TIMEOUT can be executed
1344 without any queuing now.
1348 Fixed bug in udevd, if inotify is not available. We depend on netlink
1349 uevents now, kernels without that event source will not work with that
1350 version of udev anymore.
1354 The rule parsing happens now in the daemon once at startup, all udev
1355 event processes inherit the already parsed rules from the daemon.
1356 It is shipped with SUSE10.0 and reduces heavily the system load at
1357 startup. The option to save precompiled rules and let the udev process
1358 pick the them up is removed, as it's no longer needed.
1360 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1361 device. Libsysfs is changed to "translate" the requested link into the
1362 real device path, as it would happen with the hotplug event. Otherwise
1363 device removal and the udev database will not work.
1365 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1368 A few improvements for vol_id, the filesytem probing code.
1372 Fix a stupid typo in extras/run_directory for "make install".
1374 scsi_id creates the temporary devnode now in /dev for usage with a
1375 non-writable /tmp directory.
1377 The uevent kernel socket buffer can carry app. 50.000 events now,
1378 let's see who can break this again. :)
1380 The upcoming kernel will have a new input driver core integration.
1381 Some class devices are now symlinks to the real device. libsysfs
1382 needs a fix for this to work correctly. Udevstart of older udev
1383 versions will _not_ create these devices!
1387 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1392 A bunch of mostly trivial bugfixes. From now on no node name or
1393 symlink name can contain any character than plain whitelisted ascii
1394 characters or validated utf8 byte-streams. This is needed for the
1395 /dev/disk/by-label/* links, because we import untrusted data and
1396 export it to the filesystem.
1400 More bugfixes. If udevd was started from the kernel, we don't
1401 have stdin/stdout/stderr, which broke the forked tools in some
1406 Bugfix. udevstart event ordering was broken for a long time.
1407 The new run_program() uncovered it, because /dev/null was not
1408 available while we try to run external programs.
1409 Now udevstart should create it before we run anything.
1413 Minor bugfixes and some distro rules updates. If you don't have the
1414 persistent disk rules in /dev/disk/by-*/* on your distro, just
1415 grab it from here. :)
1419 We can use socket communication now to pass events from udev to
1421 RUN+="socket:/org/freedesktop/hal/udev_event"
1422 will pass the whole udev event to the HAL daemon without the need
1423 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1427 Mostly bugfixes and see ChangeLog.
1429 The test for the existence of an environment value should be
1431 ENV{KEY}=="*" to ENV{KEY}=="?*"
1432 because "*" will not fail anymore, if the key does not exist or
1437 Bugfixes and a few tweaks described in the ChangeLog.
1441 Mostly a Bugfix release.
1443 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1444 timing with custom rules.
1448 We changed the internal rule storage format. Our large rule files took
1449 2 MB of RAM, with the change we are down to 99kB.
1451 If the device-node has been created with default name and no symlink or
1452 options are to remenber, it is not longer stored in the udevdb. HAL will
1453 need to be updated to work correctly with that change.
1455 To overrride optimization flags, OPTFLAGS may be used now.
1463 Major changes happened with this release. The goal is to take over the
1464 complete kernel-event handling and provide a more efficient way to dispatch
1465 kernel events. Replacing most of the current shell script logic and the
1466 kernel forked helper with a netlink-daemon and a rule-based event handling.
1468 o udevd listens to netlink events now. The first valid netlink event
1469 will make udevd ignore any message from udevsend that contains a
1470 SEQNUM, to avoid duplicate events. The forked events can be disabled
1472 echo "" > /proc/sys/kernel/hotplug
1473 For full support, the broken input-subsytem needs to be fixed, not to
1474 bypass the driver core.
1476 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1477 removed from udev itself and must be emulated by calling small
1478 helper binaries provided in the extras folder:
1479 make EXTRAS=extras/run_directory/
1480 will build udev_run_devd and udev_run_hotplugd, which can be called
1481 from a rule if needed:
1482 RUN+="/sbin/udev_run_hotplugd"
1483 The recommended way to handle this is to convert all the calls from
1484 the directories to explicit udev rules and get completely rid of the
1485 multiplexing. (To catch a ttyUSB event, you now no longer need to
1486 fork and exit 300 tty script instances you are not interested in, it
1487 is just one rule that matches exactly the device.)
1489 o udev handles now _all_ events not just events for class and block
1490 devices, this way it is possible to control the complete event
1491 behavior with udev rules. Especially useful for rules like:
1492 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1494 o As used in the modalias rule, udev supports now textual
1495 substitution placeholder along with the usual format chars. This
1496 needs to be documented, for now it's only visible in udev_rules_parse.c.
1498 o The rule keys support now more operations. This is documented in the
1499 man page. It is possible to add values to list-keys like the SYMLINK
1500 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1501 Also "final"-assignments are supported by using KEY:="value", which will
1502 prevent changing the key by any later rule.
1504 o kernel 2.6.12 has the "detached_state" attribute removed from
1505 sysfs, which was used to recognize sysfs population. We switched that
1506 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1507 Running this udev version on older kernels may cause a short delay for
1510 o To provide infrastructure for persistent device naming, the id programs:
1511 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1512 to export the probed data in environment key format:
1513 pim:~ # /sbin/ata_id --export /dev/hda
1514 ID_MODEL=HTS726060M9AT00
1515 ID_SERIAL=MRH401M4G6UM9B
1516 ID_REVISION=MH4OA6BA
1518 The following rules:
1519 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1520 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1523 kay@pim:~> tree /dev/disk
1526 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1527 | `-- IBM-Memory_Key -> ../../sda
1529 | |-- swap -> ../../hda1
1530 | |-- date -> ../../sda1
1531 | `-- home -> ../../hda3
1533 |-- 2E08712B0870F2E7 -> ../../hda3
1534 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1535 |-- E845-7A89 -> ../../sda1
1536 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1538 The IMPORT= operation will import these keys in the environment and make
1539 it available for later PROGRAM= and RUN= executed programs. The keys are
1540 also stored in the udevdb and can be queried from there with one of the
1543 o A few binaries are silently added to the repository, which can be used
1544 to replay kernel events from initramfs instead of using coldplug. udevd
1545 can be instructed now to queue-up events while the stored events from
1546 initramfs are filled into the udevd-queue. This code is still under
1547 development and there is no documentation now besides the code itself.
1548 The additional binaries get compiled, but are not installed by default.
1550 o There is also a temporary fix for a performance problem where too many
1551 events happen in parallel and every event needs to parse the rules.
1552 udev can now read precompiled rules stored on disk. This is likely to be
1553 replaced by a more elegant solution in a future udev version.
1557 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1558 Fix for libsysfs not to expect this file was added.
1562 All rules are applied now, but only the first matching rule with a NAME-key
1563 will be applied. All later rules with NAME-key are completely ignored. This
1564 way system supplied symlinks or permissions gets applied to user-defined
1568 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1569 to some rules, to keep the old behavior.
1571 The rules are read on "remove"-events too. That makes is possible to match
1572 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1573 instruct udev to ignore an event (OPTIONS="ignore_device").
1574 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1576 The new RUN-key supports rule-based execution of programs after device-node
1577 handling. This is meant as a general replacement for the dev.d/-directories
1578 to give fine grained control over the execution of programs.
1580 The %s{}-sysfs format char replacement values are searched at any of the
1581 devices in the device chain now, not only at the class-device.
1583 We support log priority levels now. The value udev_log in udev.conf is used
1584 to determine what is printed to syslog. This makes it possible to
1585 run a version with compiled-in debug messages in a production environment
1586 which is sometimes needed to find a bug.
1587 It is still possible to supress the inclusion of _any_ syslog usage with
1588 USE_LOG=false to create the smallest possible binaries if needed.
1589 The configured udev_log value can be overridden with the environment variable
1594 Possible use of a system-wide klibc:
1595 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1596 will link against an external klibc and our own version will be ignored.
1600 We support an unlimited count of symlinks now.
1602 If USE_STATIC=true is passed to a glibc build, we link statically and use
1603 a built-in userdb parser to resolve user and group names.
1605 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1606 we walk up the chain of physical devices to find a match.
1608 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1609 easy to skip certain attribute matches without composing rules with weird
1610 character class negations like:
1611 KERNEL="[!s][!c][!d]*"
1612 this can now be replaced with:
1614 The current simple '=' is still supported, and should work as it does today,
1615 but existing rules should be converted if possible, to be better readable.
1617 We have new ENV{}== key now, to match against a maximum of 5 environment
1620 udevstart is its own binary again, because we don't need co carry this araound
1621 with every forked event.