3 The 'devtmpfs' filesystem is required now, udev will not create or delete
4 device nodes anymore, it only adjusts permissions and ownership of device
5 nodes and maintains additional symlinks.
7 A writable /run directory (ususally tmpfs) is required now for a fully
8 functional udev, there is no longer a fallback to /dev/.udev.
10 The default 'configure' install locations have changed. Packages for systems
11 with the historic / vs. /usr split need to be adapted, otherwise udev will
12 be installed in /usr and not work properly. Example configuration options
13 to install things the traditional way are in INSTALL.
15 The default install location of the 'udevadm' tool moved from 'sbin'
16 to /usr/bin. Some tools expect udevadm in 'sbin', a symlink to udevadm
17 needs to be manually created if needed, or --bindir=/sbin be specified.
19 The expected value of '--libexecdir=' has changed and must no longer contain
22 Kernel modules are now loaded directly by linking udev to 'libkmod'. The
23 'modprobe' tool is no longer executed by udev.
25 The 'blkid' tool is no longer executed from udev rules. Udev links
26 directly to libblkid now.
28 Firmware is loaded natively by udev now, the external 'firmware' binary
31 All built-in tools can be listed and tested with 'udevadm test-builtin'.
33 The 'udevadm control --reload-rules' option has been renamed to '--reload'.
34 It now also reloads the kernel module configuration.
36 The systemd socket files use PassCredentials=yes, which is available in
39 The udev build system only creates a .xz tarball now.
41 All tabs in the source code used for indentation are replaced by spaces now. :)
51 The udev daemon moved to /lib/udev/udevd. Non-systemd init systems
52 and non-dracut initramfs image generators need to change the init
53 scripts. Alternatively the udev build needs to move udevd back to
54 /sbin or create a symlink in /sbin, which is not done by default.
56 The path_id, usb_id, input_id tools are built-in commands now and
57 the stand-alone tools do not exist anymore. Static lists of file in
58 initramfs generators need to be updated. For testing, the commands
59 can still be executed standalone with 'udevadm test-builtin <cmd>'.
61 The fusectl filesystem is no longer mounted directly from udev.
62 Systemd systems will take care of mounting fusectl and configfs
63 now. Non-systemd systems need to ship their own rule if they
64 need these filesystems auto-mounted.
66 The long deprecated keys: SYSFS=, ID=, BUS= have been removed.
68 The support for 'udevadm trigger --type=failed, and the
69 RUN{fail_event_on_error} attribute was removed.
71 The udev control socket is now created in /run/udev/control
72 and no longer as an abstract namespace one.
74 The rules to create persistent network interface and cdrom link
75 rules automatically in /etc/udev/rules.d/ have been disabled by
76 default. Explicit configuration will be required for these use
77 cases, udev will no longer try to write any persistent system
78 configuration from a device hotplug path.
84 The udev-acl extra is no longer enabled by default now. To enable it,
85 --enable-udev_acl needs to be given at ./configure time. On systemd
86 systems, the udev-acl rules prevent it from running as the functionality
93 Udev now enables kernel media-presence polling if available. Part
94 of udisks optical drive tray-handling moved to cdrom_id: The tray
95 is locked as soon as a media is detected to enable the receiving
96 of media-eject-request events. Media-eject-request events will
99 Libudev enumerate is now able to enumerate a subtree of a given
102 The mobile-action-modeswitch modeswitch tool was deleted. The
103 functionality is provided by usb_modeswitch now.
109 The systemd service files require systemd version 28. The systemd
110 socket activation make it possible now to start 'udevd' and 'udevadm
111 trigger' in parallel.
115 Fix bug in control message handling, which can lead to a failing
116 udevadm control --exit. Thanks to Jürg Billeter for help tracking
123 We require at least Linux kernel 2.6.32 now. Some platforms might
124 require a later kernel that supports accept4() and similar, or
125 need to backport the trivial syscall wiring to the older kernels.
127 The hid2hci tool moved to the bluez package and was removed.
129 Many of the extras can be --enable/--disabled at ./configure
130 time. The --disable-extras option was removed. Some extras have
131 been disabled by default. The current options and their defaults
132 can be checked with './configure --help'.
138 Udev logs a warning now if /run is not writable at udevd
139 startup. It will still fall back to /dev/.udev, but this is
140 now considered a bug.
142 The running udev daemon can now cleanly shut down with:
143 udevadm control --exit
145 Udev in initramfs should clean the state of the udev database
146 with: udevadm info --cleanup-db which will remove all state left
147 behind from events/rules in initramfs. If initramfs uses
148 --cleanup-db and device-mapper/LVM, the rules in initramfs need
149 to add OPTIONS+="db_persist" for all dm devices. This will
150 prevent removal of the udev database for these devices.
152 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
153 120 seconds per process. If that timeout is reached the spawned
154 process will be killed. The event timeout can be overwritten with
157 If systemd is used, udev gets now activated by netlink data.
158 Systemd will bind the netlink socket which will buffer all data.
159 If needed, such setup allows a seemless update of the udev daemon,
160 where no event can be lost during a udevd update/restart.
161 Packages need to make sure to: systemctl stop udev.socket udev.service
162 or 'mask' udev.service during the upgrade to prevent any unwanted
163 auto-spawning of udevd.
164 This version of udev conflicts with systemd version below 25. The
165 unchanged service files will not wirk correctly.
171 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
172 /run mountpoint is supposed to be a tmpfs mounted during early boot,
173 available and writable to for all tools at any time during bootup,
174 it replaces /var/run/, which should become a symlink some day.
176 If /run does not exist, or is not writable, udev will fall back using
179 On systemd systems with initramfs and LVM used, packagers must
180 make sure, that the systemd and initramfs versions match. The initramfs
181 needs to create the /run mountpoint for udev to store the data, and
182 mount this tmpfs to /run in the rootfs, so the that the udev database
183 is preserved for the udev version started in the rootfs.
185 The command 'udevadm info --convert-db' is gone. The udev daemon
186 itself, at startup, converts any old database version if necessary.
188 The systemd services files have been reorganized. The udev control
189 socket is bound by systemd and passed to the started udev daemon.
190 The udev-settle.service is no longer active by default. Services which
191 can not handle hotplug setups properly need to actively pull it in, to
192 act like a barrier. Alternatively the settle service can be unconditionally
193 'systemctl'enabled, and act like a barrier for basic.target.
195 The fstab_import callout is no longer built or installed. Udev
196 should not be used to mount, does not watch changes to fstab, and
197 should not mirror fstab values in the udev database.
203 New and updated keymaps.
209 The udev database has changed, After installation of a new udev
210 version, 'udevadm info --convert-db' should be called, to let the new
211 udev/libudev version read the already stored data.
213 udevadm now supports quoting of property values, and prefixing of
215 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
218 MY_DEVNAME='/dev/sda'
222 libudev now supports:
223 udev_device_get_is_initialized()
224 udev_enumerate_add_match_is_initialized()
225 to be able to skip devices the kernel has created , but udev has
228 libudev now supports:
229 udev_device_get_usec_since_initialized()
230 to retrieve the "age" of a udev device record.
232 GUdev supports a more generic GUdevEnumerator class, udev TAG
233 handling, device initialization and timestamp now.
235 The counterpart of /sys/dev/{char,block}/$major:$minor,
236 /dev/{char,block}/$major:$minor symlinks are now unconditionally
237 created, even when no rule files exist.
239 New and updated keymaps.
245 GUdev moved from /usr to /.
255 Persistent network naming rules are disabled inside of Qemu/KVM now.
257 New and updated keymaps.
259 Udev gets unconditionally enabled on systemd installations now. There
260 is no longer the need to to run 'systemctl enable udev.service'.
274 New and fixed keymaps.
276 Install systemd service files if applicable.
282 All distribution specific rules are removed from the udev source tree,
283 most of them are no longer needed. The Gentoo rules which allow to support
284 older kernel versions, which are not covered by the default rules anymore
285 has moved to rules/misc/30-kernel-compat.rules.
291 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
292 was removed from udevd.
294 Udevd now checks the kernel commandline for the following variables:
295 udev.log-priority=<syslog priority>
296 udev.children-max=<maximum number of workers>
297 udev.exec-delay=<seconds to delay the execution of RUN=>
298 to help debuging coldplug setups where the loading of a kernel
299 module crashes the system.
301 The subdirectory in the source tree rules/packages has been renamed to
302 rules/arch, anc contains only architecture specific rules now.
312 Now the udev daemon itself, does on startup:
313 - copy the content of /lib/udev/devices to /dev
314 - create the standard symlinks like /dev/std{in,out,err},
315 /dev/core, /dev/fd, ...
316 - use static node information provided by kernel modules
317 and creates these nodes to allow module on-demand loading
318 - possibly apply permissions to all ststic nodes from udev
319 rules which are annotated to match a static node
321 The default mode for a device node is 0600 now to match the kernel
322 created devtmpfs defaults. If GROUP= is specified and no MODE= is
323 given the default will be 0660.
329 Udev now gradually starts to pass control over the primary device nodes
330 and their names to the kernel, and will in the end only manage the
331 permissions of the node, and possibly create additional symlinks.
332 As a first step NAME="" will be ignored, and NAME= setings with names
333 other than the kernel provided name will result in a logged warning.
334 Kernels that don't provide device names, or devtmpfs is not used, will
335 still work as they did before, but it is strongly recommended to use
336 only the same names for the primary device node as the recent kernel
337 provides for all devices.
341 Fix broken firmware loader search path.
347 "udevadm trigger" defaults to "change" events now instead of "add"
348 events. The "udev boot script" might need to add "--action=add" to
349 the trigger command if not already there, in case the initial coldplug
350 events are expected as "add" events.
352 The option "all_partitons" was removed from udev. This should not be
353 needed for usual hardware. Udev can not safely make assumptions
354 about non-existing partition major/minor numbers, and therefore no
355 longer provide this unreliable and unsafe option.
357 The option "ignore_remove" was removed from udev. With devtmpfs
358 udev passed control over device nodes to the kernel. This option
359 should not be needed, or can not work as advertised. Neither
360 udev nor the kernel will remove device nodes which are copied from
361 the /lib/udev/devices/ directory.
363 All "add|change" matches are replaced by "!remove" in the rules and
364 in the udev logic. All types of events will update possible symlinks
365 and permissions, only "remove" is handled special now.
367 The modem modeswitch extra was removed and the external usb_modeswitch
368 program should be used instead.
370 New and fixed keymaps.
380 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
381 depend on the current sysfs layout and the information not available in the
382 deprecated layout. All remaining support for the deprecated sysfs layout is
387 Fix for a possible endless loop in the new input_id program.
393 The option "ignore_device" does no longer exist. There is no way to
394 ignore an event, as libudev events can not be suppressed by rules.
395 It only prevented RUN keys from being executed, which results in an
396 inconsistent behavior in current setups.
398 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
399 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
402 The support for the deprecated IDE devices has been removed from the
403 default set of rules. Distros who still care about non-libata drivers
404 need to add the rules to the compat rules file.
406 The ID_CLASS property on input devices has been replaced by the more accurate
407 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
408 determined by the new "input_id" prober now. Some devices, such as touchpads,
409 can have several classes. So if you previously had custom udev rules which e. g.
410 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
411 ENV{ID_INPUT_KEYBOARD}=="?*".
417 To support DEVPATH strings larger than the maximum file name length, the
418 private udev database format has changed. If some software still reads the
419 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
420 Please do not port anything to the new format again, everything in /dev/.udev
421 is and always was private to udev, and may and will change any time without
424 Multiple devices claiming the same names in /dev are limited to symlinks
425 only now. Mixing identical symlink names and node names is not supported.
426 This reduces the amount of data in the database significantly.
428 NAME="%k" causes a warning now. It's is and always was completely superfluous.
429 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
432 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
433 if they are not the default. To support older kernels, the NAME= rules need to
434 be added to the compat rules file.
436 Symlinks to udevadm with the old command names are no longer resolved to
437 the udevadm commands.
439 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
442 The option "last_rule" does no longer exist. Its use breaks too many
443 things which expect to be run from independent later rules, and is an idication
444 that something needs to be fixed properly instead.
446 The gudev API is no longer marked as experimental,
447 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
448 is enabled by default now. Various projects already depend on introspection
449 information to bind dynamic languages to the gudev interfaces.
455 The udevadm trigger "--retry-failed" option, which is replaced since quite
456 a while by "--type=failed" is removed.
458 The failed tracking was not working at all for a few releases. The RUN
459 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
460 default is not to track any failing RUN executions.
462 New keymaps, new modem, hid2hci updated.
466 Fix possible crash in udevd when worker processes are busy, rules are
467 changed at the same time, and workers get killed to reload the rules.
473 Properties set with ENV{.FOO}="bar" are marked private by starting the
474 name with a '.'. They will not be stored in the database, and not be
475 exported with the event.
477 Firmware files are looked up in:
478 /lib/firmware/updates/$(uname -r)
479 /lib/firmware/updates
480 /lib/firmware/$(uname -r)
484 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
485 ata_id, instead of scsi_id, is the default tool now for ATA devices.
491 The configure options have changed because another library needs to be
492 installed in a different location. Instead of exec_prefix and udev_prefix,
493 libdir, rootlibdir and libexecdir are used. The Details are explained in
496 Event processes now get re-used after they handled an event. This reduces
497 the number of forks and the pressure on the CPU significantly, because
498 cloned event processes no longer cause page faults in the main daemon.
499 After the events have settled, a few worker processes stay around for
500 future events, all others get cleaned up.
502 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
503 Also inotify support is mandatory now to run udev.
505 The format of the queue exported by the udev damon has changed. There is
506 no longer a /dev/.udev/queue/ directory. The current event queue can be
507 accessed with udevadm settle and libudedv.
509 Libudev does not have the unstable API header anymore. From now on,
510 incompatible changes will be handled by bumping the library major version.
512 To build udev from the git tree gtk-doc is needed now. The tarballs will
513 build without it and contain the pre-built documentation. An online copy
515 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
517 The tools from the udev-extras repository have been merged into the main
518 udev repository. Some of the extras have larger external dependencies, and
519 they can be disabled with the configure switch --disable-extras.
525 The program vol_id and the library libvolume_id are removed from the
526 repository. Libvolume_id is merged with libblkid from the util-linux-ng
527 package. Persistent disk links for label and uuid depend on the
528 util-linux-ng version (2.15) of blkid now. Older versions of blkid
529 can not be used with udev.
531 Libudev allows to subscribe to udev events. To prevent unwanted messages
532 to be delivered, and waking up the subscribing process, a filter can be
533 installed, to drop messages inside a kernel socket filter. The filters
534 match on the <subsytem>:<devtype> properties of the device.
535 This is part of the ongoing effort to replace HAL, and switch current
536 users over to directly use libudev.
537 Libudev is still marked as experimental, and its interface might
538 eventually change if needed, but no major changes of the currently exported
539 interface are expected anymore, and a first stable release should happen
542 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
543 is not supported since while and udevd will log an error message at
544 startup. It should still be able to boot-up, but advanced rules and system
545 services which depend on the information not available in the old sysfs
546 format will fail to work correctly.
548 DVB device naming is supplied by the kernel now. In case older kernels
549 need to be supported, the old shell script should be added to a compat
556 The processed udev events get send back to the netlink socket. Libudev
557 provides access to these events. This is work-in-progress, to replace
558 the DeviceKit daemon functionality directly with libudev. There are
559 upcoming kernel changes to allow non-root users to subcribe to these
566 "udevadm settle" now optionally accepts a range of events to wait for,
567 instead of waiting for "all" events.
573 The installed watch for block device metadata changes is now removed
574 during event hadling, because some (broken) tools may be called from udev
575 rules and (wrongly) open the device with write access. After the finished
576 event handling the watch is restored.
582 Device nodes can be watched for changes with inotify with OPTIONS="watch".
583 If closed after being opened for writing, a "change" uevent will occur.
584 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
590 The udevadm test command has no longer a --force option, nodes and symlinks
591 are always updated with a test run now.
593 The udevd daemon can be started with --resolve-names=never to avoid all user
594 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
595 lookup user and groups every time events are handled.
601 We are currently merging the Ubuntu rules in the udev default rules,
602 and get one step closer to provide a common Linux /dev setup, regarding
603 device names, symlinks, and default device permissions. On udev startup,
604 we now expect the following groups to be resolvable to their ids with
606 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
607 LDAP setups need to make sure, that these groups are always resolvable at
608 bootup, with only the rootfs mounted, and without network access available.
610 Some systems may need to add some new, currently not used groups, or need
611 to add some users to new groups, but the cost of this change is minimal,
612 compared to the pain the current, rather random, differences between the
613 various distributions cause for upstream projects and third-party vendors.
615 In general, "normal" users who log into a machine should never be a member
616 of any such group, but the device-access should be managed by dynamic ACLs,
617 which get added and removed for the specific users on login/logout and
618 session activity/inactivity. These groups are only provided for custom setups,
619 and mainly system services, to allow proper privilege separation.
620 A video-streaming daemon uid would be a member of "audio" and "video", to get
621 access to the sound and video devices, but no "normal" user should ever belong
622 to the "audio" group, because he could listen to the built-in microphone with
623 any ssh-session established from the other side of the world.
625 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
626 which do not depend on the kernel device name. As usual, unique
627 devices - only a single one per product connected, or a real
628 USB serial number in the device - are always found with the same
629 name in the by-id/ directory.
630 Completely identical devices may overwrite their names in by-id/
631 and can only be found reliably in the by-path/ directory. Devices
632 specified by by-path/ must not change their connection, like the
633 USB port number they are plugged in, to keep their name.
635 To support some advanced features, Linux 2.6.22 is the oldest supported
636 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
637 supported. Older kernels should still work, and devices nodes should be
638 reliably created, but some rules and libudev will not work correctly because
639 the old kernels do not provide the expected information or interfaces.
645 Fix for a possible segfault while swapping network interface names in udev
652 The group "video" is part of the default rules now.
656 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
657 block devices in some cases. No common distro uses this option anymore,
658 and we do not get enough testing for this and recent udev versions. If
659 this option is not needed to run some old distro with a new kernel,
660 it should be disabled in the kernel config.
662 Bugfix for the $links substitution variable, which may crash if no links
663 are created. This should not happen in usual setups because we always
664 create /dev/{block,char}/ links.
666 The strings of the parsed rules, which are kept in memory, no longer
667 contain duplicate entries, or duplicate tails of strings. This, and the
668 new rules parsing/matching code reduces the total in-memory size of
669 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
672 The export of DEVTYPE=disk/partition got removed from the default
673 rules. This value is available from the kernel. The pnp shell script
674 modprobe hack is removed from the default rules. ACPI devices have _proper_
675 modalias support and take care of the same functionality.
676 Installations which support old kernels, but install current default
677 udev rules may want to add that to the compat rules file.
679 Libvolume_id now always probes for all known filesystems, and does not
680 stop at the first match. Some filesystems are marked as "exclusive probe",
681 and if any other filesytem type matches at the same time, libvolume_id
682 will, by default, not return any probing result. This is intended to prevent
683 mis-detection with conflicting left-over signatures found from earlier
684 file system formats. That way, we no longer depend on the probe-order
685 in case of multiple competing signatures. In some setups the kernel allows
686 to mount a volume with just the old filesystem signature still in place.
687 This may damage the new filesystem and cause data-loss, just by mounting
688 it. Because volume_id can not decide which one the correct signature is,
689 the wrong signatures need to be removed manually from the volume, or the
690 volume needs to be reformatted, to enable filesystem detection and possible
695 Fix segfault if compiled without optimization and dbg() does not get
696 compiled out and uses variables which are not available.
700 Bugfixes. (And maybe new bugs. :))
702 The rule matching engine got converted from a rule list to a token
703 array which reduced the in-memory rules representation of a full
704 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
705 Limits like 5 ENV and ATTR matches, and one single instance for most
706 other keys per rule are gone.
708 The NAME assignment is no longer special cased. If later rules assign
709 a NAME value again, the former value will be overwritten. As usual
710 for most other keys, the NAME value can be protected by doing a final
711 assignment with NAME:="<value>".
713 All udev code now uses libudev, which is also exported. The library
714 is still under development, marked as experimental, and its interface
715 may change as long as the DeviceKit integration is not finished.
717 Many thanks to Alan Jenkins for his continuous help, and finding and
718 optimizing some of the computing expensive parts.
724 Kernel devices and device nodes are connected now by reverse indizes in
725 /sys and /dev. A device number retrieved by a stat() or similar, the
726 kernel device directory can be found by looking up:
727 /sys/dev/{block,char}/<maj>:<min>
728 and the device node of the same device by looking up:
729 /dev/{block,char}/<maj>:<min>
733 Fix recently introduced bug, which caused a compilation without large
734 file support, where vol_id does not recognize raid signatures at the end
737 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
738 Seems some kernel versions prevent the creation of the ieee-* links,
739 so people used the scsi-* link which disappeared now.
741 More libudev work. Almost all udevadm functionality comes from libudev
744 udevadm trigger has a new option --type, which allows to trigger events
745 for "devices", for "subsystems", or "failed" devices. The old option
746 --retry-failed" still works, but is no longer mentioned in the man page.
752 The udevadm info --device-id-of-file= output has changed to use
753 the obvious format. Possible current users should use the --export
754 option which is not affected.
756 The old udev commands symlinks to udevadm are not installed, if
757 these symlinks are used, a warning is printed.
763 Optical drive's media is no longer probed for raid signatures,
764 reading the end of the device causes some devices to malfunction.
765 Also the offset of the last session found is used now to probe
768 The volume_id library got a major version number update to 1,
769 some deprecated functions are removed.
771 A shared library "libudev" gets installed now to provide access
772 to udev device information. DeviceKit, the successor of HAL, will
773 need this library to access the udev database and search sysfs for
775 The library is currently in an experimental state, also the API is
776 expected to change, as long as the DeviceKit integration is not
781 We use ./configure now. See INSTALL for details. Current
784 "/usr" - prefix for man pages, include files
786 "" - the root filesystem, prefix for libs and binaries
790 "lib" - directory name for libraries, not a path name
791 multilib 64bit systems may use "lib64" instead of "lib"
793 compile-in verbose debug messages
795 disable all logging and compile-out all log strings
797 link against SELInux libraries, to set the expected context
800 In the default rules, the group "disk" gets permissions 0660 instead
801 of 0640. One small step closer to unify distro rules. Some day, all
802 distros hopefully end up with the same set of rules.
804 No symlinks to udevadm are installed anymore, if they are still needed,
805 they should be provided by the package.
811 Default udev rules, which are not supposed to be edited by the user, should
812 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
813 the udev package and will be replaced with an update. Udev will pick up rule
815 /lib/udev/rules.d/ - default installed rules
816 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
817 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
818 It does not matter in which directory a rule file lives, all files are sorted
821 To help creating /dev/root, we have now:
822 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
825 In case the current --device-id-of-file is already used, please switch to
826 the --export format version, it saves the output parsing and the old
827 format will be changed to use ':' as a separator, like the format in the
832 Fix cdrom_id to properly recognize blank media.
838 Tape drive id-data is queried from /dev/bsg/* instead of the tape
839 nodes. This avoids rewinding tapes on open().
845 The symlinks udevcontrol and udevtrigger are no longer installed by
848 The scsi_id program does not depend on sysfs anymore. It can speak
849 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
850 data, which should solve some old problems with tape devices, where
851 we better do not open all tape device nodes to identify the device.
857 The cdrom_id program is replaced by an advanced version, which can
858 detect most common device types, and also properties of the inserted
859 media. This is part of moving some basic functionality from HAL into
860 udev (and the kernel).
866 The last WAIT_FOR_SYSFS rule is removed from the default rules.
868 The symlinks to udevadm for the debugging tools: udevmonitor and
869 udevtest are no longer created.
871 The symlinks to the udevadm man page for the old tool names are
874 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
875 should be prefixed with '@' to indicate that the path is not a
886 Udevstart is removed from the tree, it did not get installed for
887 a long time now, and is long replaced by trigger and settle.
893 All udev tools are merged into a single binary called udevadm.
894 The old names of the tools are built-in commands in udevadm now.
895 Symlinks to udevadm, with the names of the old tools, provide
896 the same functionality as the standalone tools. There is also
897 only a single udevadm.8 man page left for all tools.
899 Tools like mkinitramfs should be checked, if they need to include
900 udevadm in the list of files.
910 The etc/udev/rules.d/ directory now contains a default set of basic
911 udev rules. This initial version is the result of a rules file merge
912 of Fedora and openSUSE. For these both distros only a few specific
913 rules are left in their own file, named after the distro. Rules which
914 are optionally installed, because they are only valid for a specific
915 architecture, or rules for subsystems which are not always used are
916 in etc/udev/packages/.
922 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
923 actions by dynamically created rules.
925 SYMLINK=="<value>" matches agains the entries in the list of
926 currently defined symlinks. The links are not created in the
927 filesystem at that point in time, but the values can be matched.
929 RUN{ignore_error}+="<program>" will ignore any exit code from the
930 program and not record as a failed event.
936 Final merge of patches/features from the Ubuntu package.
942 Control characters in filesystem label strings are no longer silenty
943 removed, but hex-encoded, to be able to uniquely identify the device
944 by its symlink in /dev/disk/by-label/.
945 If libvolume_id is used by mount(8), LABEL= will work as expected,
946 if slashes or other characters are used in the label string.
948 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
949 can be specified now. The TEST key accepts an optional mode mask
950 TEST{0100}=="<is executable file>".
952 Scsi_id now supports a mode without expecting scsi-specific sysfs
953 entries to allow the extraction of cciss-device persistent properties.
959 In the future, we may see uuid's which are just simple character
960 strings (see the DDF Raid Specification). For that reason vol_id now
961 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
962 the creation of symlinks, the *_SAFE values ensure, that no control
963 or whitespace characters are used in the filename.
965 Possible users of libvolume_id, please use the volume_id_get_* functions.
966 The public struct will go away in a future release of the library.
972 Removal of useless extras/eventrecorder.sh.
982 The directory multiplexer for dev.d/ and hotplug.d are finally removed
983 from the udev package.
989 Symlinks can have priorities now, the priority is assigned to the device
990 and specified with OPTIONS="link_priority=100". Devices with higher
991 priorities overwrite the symlinks of devices with lower priorities.
992 If the device that currently owns the link, goes away, the symlink
993 will be removed, and recreated, pointing to the next device with the
994 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
995 more reliable, if multiple devices contain the same metadata and overwrite
998 The dasd_id program is removed from the udev tree, and dasdinfo, with the
999 needed rules, are part of the s390-tools now.
1001 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
1002 we may get the scsi sysfs mess fixed some day, and this will only catch
1003 the devices we are looking for.
1005 USB serial numbers for storage devices have the target:lun now appended,
1006 to make it possibble to distinguish broken multi-lun devices with all
1007 the same SCSI identifiers.
1009 Note: The extra "run_directory" which searches and executes stuff in
1010 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
1011 with the next release. Make sure, that you don't use it anymore, or
1012 provides your own implementation of that inefficient stuff.
1013 We are tired of reports about a "slow udev", because these directories
1014 contain stuff, that runs with _every_ event, instead of using rules,
1015 that run programs only for the matching events.
1025 DRIVER== will match only for devices that actually have a real
1026 driver. DRIVERS== must be used, if parent devices should be
1027 included in the match.
1029 Libvolume_id's "linux_raid" detection needed another fix.
1037 Add additional check to volume_id detection of via_raid, cause
1038 some company decided to put a matching pattern all over the empty
1039 storage area of their music players.
1043 Fix path_id for SAS devices.
1047 The udev daemon can be started with --debug-trace now, which will
1048 execute all events serialized to get a chance to catch a possible
1049 action that crashes the box.
1051 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
1052 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
1053 are excluded from the warning. Referencing parent attributes directly
1054 may break when something in the kernel driver model changes. Udev will
1055 just find the attribute by walking up the parent chain.
1057 Udevtrigger now sorts the list of devices depending on the device
1058 dependency, so a "usb" device is triggered after the parent "pci"
1063 Revert persistent-storage ata-serial '_' '-' replacement.
1069 Udevtrigger can now filter the list of devices to be triggered. Matches
1070 for subsystems or sysfs attributes can be specified.
1072 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1073 zero-sized files to avoid pointing to /sys and confuse broken tools which
1074 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1077 The rules and scripts to create udev rules for persistent network
1078 devices and optical drives are in the extras/rules_generator directory
1079 now. If you use something similar, please consider replacing your own
1080 version with this, to share the support effort. The rule_generator
1081 installs its own rules into /etc/udev/rules.d.
1083 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1084 the rule_generator depends on cdrom_id to be called in an earlier rule.
1090 Renaming of some key names (the old names still work):
1091 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1092 (The behavior of the key DRIVER will change soon in one of the next
1093 releases, to match only the event device, please switch to DRIVERS
1094 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1096 With the new key names, we have a more consistent and simpler scheme.
1097 We can match the properties of the event device only, with: KERNEL,
1098 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1099 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1100 longer mentioned in the man page and should be switched in the rule
1103 ATTR{file}="value" can be used now, to write to a sysfs file of the
1104 event device. Instead of:
1105 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1107 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1109 All the PHYSDEV* keys are deprecated and will be removed from a
1111 PHYDEVPATH - is the path of a parent device and should not be
1113 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1114 matched with SUBSYSTEMS==
1115 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1116 Newer kernels will have DRIVER in the environment,
1117 for older kernels udev puts in. Class device will
1118 no longer carry this property of a parent and
1119 DRIVERS== can be used to match such a parent value.
1120 Note that ENV{DRIVER} is only available for a few bus devices, where
1121 the driver is already bound at device event time. On coldplug, the
1122 events for a lot devices are already bound to a driver, and they will have
1123 that value set. But on hotplug, at the time the kernel creates the device,
1124 it can't know what driver may claim the device after that, therefore
1125 in most cases it will be empty.
1127 Failed events should now be re-triggered with:
1128 udevtrigger --retry-failed.
1129 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1130 files private to the udev tools. We may need to switch the current symlink
1131 target, cause some obviously broken tools try to scan all files in /dev
1132 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1133 million times. This takes ages on slow boxes.
1135 The udevinfo attribute walk (-a) now works with giving a device node
1136 name (-n) instead of a devpath (-p). The query now always works, also when
1137 no database file was created by udev.
1139 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1140 getpwnam() and getgrnam() now. One of the next releases will depend on
1141 fnmatch() and may use getopt_long().
1145 Bugfixes and small improvements.
1149 Fix path_id for recent kernels.
1155 Added support for swapping network interface names, by temporarily
1156 renaming the device and wait for the target name to become free.
1160 The built-in MODALIAS key and substitution is removed.
1164 The binary firmware helper is replaced by the usual simple
1165 shell script. Udevsend is removed from the tree.
1173 Some more keys require the correct use of '==' and '=' depending
1174 on the kind of operation beeing an assignment or a match. Rules
1175 with invalid operations are skipped and logged to syslog. Please
1176 test with udevtest if the parsing of your rules throws errors and
1177 fix possibly broken rules.
1181 Provide "udevsettle" to wait for all current udev events to finish.
1182 It also watches the current kernel netlink queue by comparing the
1183 even sequence number to make sure that there are no current pending
1184 events that have not already arrived in the daemon.
1188 Fix rule to skip persistent rules for removable IDE devices, which
1189 also skipped optical IDE drives.
1191 All *_id program are installed in /lib/udev/ by default now.
1193 No binary is stripped anymore as this should be done in the
1194 packaging process and not at build time.
1196 libvolume_id is provided as a shared library now and vol_id is
1197 linked against it. Also one of the next HAL versions will require
1198 this library, and the HAL build process will also require the
1199 header file to be installed. The copy of the same code in HAL will
1200 be removed to have only a single copy left on the system.
1204 Add persistent links for SCSI tapes. The rules file is renamed
1205 to 60-persistent-storage.rules.
1207 Create persistent path for usb devices. Can be used for all sorts
1208 of devices that can't be distinguished by other properties like
1209 multiple identical keyboards and mice connected to the same box.
1211 Provide "udevtrigger" program to request events on coldplug. The
1212 shell script is much too slow with thousends of devices.
1216 Fix persistent disk rules to exclude removable IDE drives.
1218 Warn if %e, $modalias or MODALIAS is used.
1222 Fix queue export, which wasn't correct for subsequent add/remove
1223 events for the same device.
1227 Fix cramfs detection on big endian.
1229 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1234 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1235 attributes were only checked at the parent device that matched the
1236 by BUS requested subsystem. Fix it to also look at the device we
1237 received the event for.
1239 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1244 Fix a bug where NAME="" would prevent RUN from beeing executed.
1246 RUN="/bin/program" does not longer automatically add the subsystem
1247 as the first parameter. This is from the days of /sbin/hotplug
1248 which is dead now and it's just confusing to need to add a space at
1249 the end of the program name to prevent this.
1250 If you use rules that need the subsystem as the first parameter,
1251 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1252 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1256 The udev man page has moved to udev(7) as it does not describe a command
1257 anymore. The programs udev, udevstart and udevsend are no longer installed
1258 by default and must be copied manually, if they should be installed or
1259 included in a package.
1261 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1262 the ignore rule was applied.
1264 More preparation for future sysfs changes. usb_id and scsi_id no longer
1265 depend on a magic order of devices in the /devices chain. Specific devices
1266 should be requested by their subsytem.
1268 This will always find the scsi parent device without depending on a specific
1270 dev = sysfs_device_get(devpath);
1271 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1273 The "device" link in the current sysfs layout will be automatically
1274 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1275 parent in the devpath. If a device is requested by it's symlink, like all
1276 class devices in the new sysfs layout will look like, it gets automatically
1277 resolved and substituted with the real devpath and not the symlink path.
1280 A similar logic must be applied to _all_ sysfs users, including
1281 scripts, that search along parent devices in sysfs. The explicit use of
1282 the "device" link must be avoided. With the future sysfs layout all
1283 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1284 back to the "class" or the "bus". The layout of the parent devices in
1285 /devices is not necessarily expected to be stable across kernel releases and
1286 searching for parents by their subsystem should make sysfs users tolerant
1287 for changed parent chains.
1291 Prepare udev to work with the experimental kernel patch, that moves
1292 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1294 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1295 moving the class devices to /sys/devices.
1297 Thanks again to Marco for help finding a hopefully nice compromise
1298 to make %b simpler and working again.
1302 Complete removal of libsysfs, replaced by simple helper functions
1303 which are much simpler and a bit faster. The udev daemon operatesentirely
1304 on event parameters and does not use sysfs for simple rules anymore.
1305 Please report any new bugs/problems, that may be caused by this big
1306 change. They will be fixed immediately.
1308 The enumeration format character '%e' is deprecated and will be
1309 removed sometimes from a future udev version. It never worked correctly
1310 outside of udevstart, so we can't use it with the new parallel
1311 coldplug. A simple enumeration is as useless as the devfs naming
1312 scheme, just get rid of both if you still use it.
1314 MODALIAS and $modalias is not needed and will be removed from one of
1315 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1316 the sysfs "modalias" value.
1318 Thanks a lot to Marco for all his help on finding and fixing bugs.
1322 Let scsi_id request libata drive serial numbers from page 0x80.
1324 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1325 added /dev/disk/by-name/* for device mapper device names.
1327 Removed %e from the man page. It never worked reliably outside
1328 of udevstart and udevstart is no longer recommended to use.
1332 Symlinks are now exported to the event environment. Hopefully it's no
1333 longer needed to run udevinfo from an event process, like it was
1334 mentioned on the hotplug list:
1335 UDEV [1134776873.702967] add@/block/sdb
1338 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1342 Fix a problem if udevsend is used as the hotplug handler and tries to use
1343 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1344 and this kind of problems will hopefully go away soon.
1348 All built-in logic to work around bad sysfs timing is removed with this
1349 version. The need to wait for sysfs files is almost fixed with a kernel
1350 version that doesn't work with this udev version anyway. Until we fix
1351 the timing of the "bus" link creation, the former integrated logic should
1352 be emulated by a rule placed before all other rules:
1353 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1355 The option "udev_db" does no longer exist. All udev state will be in
1356 /$udev_root/.udev/ now, there is no longer an option to set this
1358 If the init script or something else used this value, just depend on
1359 this hardcoded path. But remember _all_content_ of this directory is
1360 still private to udev and can change at any time.
1362 Default location for rule sripts and helper programs is now: /lib/udev/.
1363 Everything that is not useful on the commandline should go into this
1364 directory. Some of the helpers in the extras folder are installed there
1365 now. The rules need to be changed, to find the helpers there.
1367 Also /lib/udev/devices is recommended as a directory where packages or
1368 the user can place real device nodes, which get copied over to /dev at
1369 every boot. This should replace the various solutions with custom config
1372 Udevsend does no longer start the udev daemon. This must be done with
1373 the init script that prepares /dev on tmpfs and creates the initial nodes,
1374 before starting the daemon.
1378 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1381 The copy of klibc is removed. A systemwide installed version of klibc
1382 should be used to build a klibc udev now.
1386 NAME="" will not create any nodes, but execute RUN keys. To completely
1387 ignore an event the OPTION "ignore_device" should be used.
1389 After removal of the reorder queue, events with a TIMEOUT can be executed
1390 without any queuing now.
1394 Fixed bug in udevd, if inotify is not available. We depend on netlink
1395 uevents now, kernels without that event source will not work with that
1396 version of udev anymore.
1400 The rule parsing happens now in the daemon once at startup, all udev
1401 event processes inherit the already parsed rules from the daemon.
1402 It is shipped with SUSE10.0 and reduces heavily the system load at
1403 startup. The option to save precompiled rules and let the udev process
1404 pick the them up is removed, as it's no longer needed.
1406 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1407 device. Libsysfs is changed to "translate" the requested link into the
1408 real device path, as it would happen with the hotplug event. Otherwise
1409 device removal and the udev database will not work.
1411 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1414 A few improvements for vol_id, the filesytem probing code.
1418 Fix a stupid typo in extras/run_directory for "make install".
1420 scsi_id creates the temporary devnode now in /dev for usage with a
1421 non-writable /tmp directory.
1423 The uevent kernel socket buffer can carry app. 50.000 events now,
1424 let's see who can break this again. :)
1426 The upcoming kernel will have a new input driver core integration.
1427 Some class devices are now symlinks to the real device. libsysfs
1428 needs a fix for this to work correctly. Udevstart of older udev
1429 versions will _not_ create these devices!
1433 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1438 A bunch of mostly trivial bugfixes. From now on no node name or
1439 symlink name can contain any character than plain whitelisted ascii
1440 characters or validated utf8 byte-streams. This is needed for the
1441 /dev/disk/by-label/* links, because we import untrusted data and
1442 export it to the filesystem.
1446 More bugfixes. If udevd was started from the kernel, we don't
1447 have stdin/stdout/stderr, which broke the forked tools in some
1452 Bugfix. udevstart event ordering was broken for a long time.
1453 The new run_program() uncovered it, because /dev/null was not
1454 available while we try to run external programs.
1455 Now udevstart should create it before we run anything.
1459 Minor bugfixes and some distro rules updates. If you don't have the
1460 persistent disk rules in /dev/disk/by-*/* on your distro, just
1461 grab it from here. :)
1465 We can use socket communication now to pass events from udev to
1467 RUN+="socket:/org/freedesktop/hal/udev_event"
1468 will pass the whole udev event to the HAL daemon without the need
1469 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1473 Mostly bugfixes and see ChangeLog.
1475 The test for the existence of an environment value should be
1477 ENV{KEY}=="*" to ENV{KEY}=="?*"
1478 because "*" will not fail anymore, if the key does not exist or
1483 Bugfixes and a few tweaks described in the ChangeLog.
1487 Mostly a Bugfix release.
1489 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1490 timing with custom rules.
1494 We changed the internal rule storage format. Our large rule files took
1495 2 MB of RAM, with the change we are down to 99kB.
1497 If the device-node has been created with default name and no symlink or
1498 options are to remenber, it is not longer stored in the udevdb. HAL will
1499 need to be updated to work correctly with that change.
1501 To overrride optimization flags, OPTFLAGS may be used now.
1509 Major changes happened with this release. The goal is to take over the
1510 complete kernel-event handling and provide a more efficient way to dispatch
1511 kernel events. Replacing most of the current shell script logic and the
1512 kernel forked helper with a netlink-daemon and a rule-based event handling.
1514 o udevd listens to netlink events now. The first valid netlink event
1515 will make udevd ignore any message from udevsend that contains a
1516 SEQNUM, to avoid duplicate events. The forked events can be disabled
1518 echo "" > /proc/sys/kernel/hotplug
1519 For full support, the broken input-subsytem needs to be fixed, not to
1520 bypass the driver core.
1522 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1523 removed from udev itself and must be emulated by calling small
1524 helper binaries provided in the extras folder:
1525 make EXTRAS=extras/run_directory/
1526 will build udev_run_devd and udev_run_hotplugd, which can be called
1527 from a rule if needed:
1528 RUN+="/sbin/udev_run_hotplugd"
1529 The recommended way to handle this is to convert all the calls from
1530 the directories to explicit udev rules and get completely rid of the
1531 multiplexing. (To catch a ttyUSB event, you now no longer need to
1532 fork and exit 300 tty script instances you are not interested in, it
1533 is just one rule that matches exactly the device.)
1535 o udev handles now _all_ events not just events for class and block
1536 devices, this way it is possible to control the complete event
1537 behavior with udev rules. Especially useful for rules like:
1538 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1540 o As used in the modalias rule, udev supports now textual
1541 substitution placeholder along with the usual format chars. This
1542 needs to be documented, for now it's only visible in udev_rules_parse.c.
1544 o The rule keys support now more operations. This is documented in the
1545 man page. It is possible to add values to list-keys like the SYMLINK
1546 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1547 Also "final"-assignments are supported by using KEY:="value", which will
1548 prevent changing the key by any later rule.
1550 o kernel 2.6.12 has the "detached_state" attribute removed from
1551 sysfs, which was used to recognize sysfs population. We switched that
1552 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1553 Running this udev version on older kernels may cause a short delay for
1556 o To provide infrastructure for persistent device naming, the id programs:
1557 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1558 to export the probed data in environment key format:
1559 pim:~ # /sbin/ata_id --export /dev/hda
1560 ID_MODEL=HTS726060M9AT00
1561 ID_SERIAL=MRH401M4G6UM9B
1562 ID_REVISION=MH4OA6BA
1564 The following rules:
1565 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1566 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1569 kay@pim:~> tree /dev/disk
1572 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1573 | `-- IBM-Memory_Key -> ../../sda
1575 | |-- swap -> ../../hda1
1576 | |-- date -> ../../sda1
1577 | `-- home -> ../../hda3
1579 |-- 2E08712B0870F2E7 -> ../../hda3
1580 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1581 |-- E845-7A89 -> ../../sda1
1582 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1584 The IMPORT= operation will import these keys in the environment and make
1585 it available for later PROGRAM= and RUN= executed programs. The keys are
1586 also stored in the udevdb and can be queried from there with one of the
1589 o A few binaries are silently added to the repository, which can be used
1590 to replay kernel events from initramfs instead of using coldplug. udevd
1591 can be instructed now to queue-up events while the stored events from
1592 initramfs are filled into the udevd-queue. This code is still under
1593 development and there is no documentation now besides the code itself.
1594 The additional binaries get compiled, but are not installed by default.
1596 o There is also a temporary fix for a performance problem where too many
1597 events happen in parallel and every event needs to parse the rules.
1598 udev can now read precompiled rules stored on disk. This is likely to be
1599 replaced by a more elegant solution in a future udev version.
1603 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1604 Fix for libsysfs not to expect this file was added.
1608 All rules are applied now, but only the first matching rule with a NAME-key
1609 will be applied. All later rules with NAME-key are completely ignored. This
1610 way system supplied symlinks or permissions gets applied to user-defined
1614 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1615 to some rules, to keep the old behavior.
1617 The rules are read on "remove"-events too. That makes is possible to match
1618 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1619 instruct udev to ignore an event (OPTIONS="ignore_device").
1620 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1622 The new RUN-key supports rule-based execution of programs after device-node
1623 handling. This is meant as a general replacement for the dev.d/-directories
1624 to give fine grained control over the execution of programs.
1626 The %s{}-sysfs format char replacement values are searched at any of the
1627 devices in the device chain now, not only at the class-device.
1629 We support log priority levels now. The value udev_log in udev.conf is used
1630 to determine what is printed to syslog. This makes it possible to
1631 run a version with compiled-in debug messages in a production environment
1632 which is sometimes needed to find a bug.
1633 It is still possible to supress the inclusion of _any_ syslog usage with
1634 USE_LOG=false to create the smallest possible binaries if needed.
1635 The configured udev_log value can be overridden with the environment variable
1640 Possible use of a system-wide klibc:
1641 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1642 will link against an external klibc and our own version will be ignored.
1646 We support an unlimited count of symlinks now.
1648 If USE_STATIC=true is passed to a glibc build, we link statically and use
1649 a built-in userdb parser to resolve user and group names.
1651 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1652 we walk up the chain of physical devices to find a match.
1654 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1655 easy to skip certain attribute matches without composing rules with weird
1656 character class negations like:
1657 KERNEL="[!s][!c][!d]*"
1658 this can now be replaced with:
1660 The current simple '=' is still supported, and should work as it does today,
1661 but existing rules should be converted if possible, to be better readable.
1663 We have new ENV{}== key now, to match against a maximum of 5 environment
1666 udevstart is its own binary again, because we don't need co carry this araound
1667 with every forked event.