5 The path_id, usb_id, input_id tools are built-in commands now
6 and the stand-alone tools do not exist anymore. For testing,
7 the commands can be run with 'udevadm test-builtin <cmd>'.
9 The fusectl filesystem is no longer mounted directly from udev.
10 Systemd systems will take care of mounting fusectl and configfs
11 now. Non-systemd systems need to ship their own rule if they
12 need these filesystems auto-mounted.
14 The long deprecated keys: SYSFS, ID, BUS have been removed.
16 The support for 'udevadm trigger --type=failed, and the
17 RUN{fail_event_on_error} attribute was removed.
19 The udev control socket is now created in /run/udev/control
20 and no longer as an abstract namespace one.
26 The udev-acl extra is no longer enabled by default now. To enable it,
27 --enable-udev_acl needs to be given at ./configure time. On systemd
28 systems, the udev-acl rules prevent it from running as the functionality
35 Udev now enables kernel media-presence polling if available. Part
36 of udisks optical drive tray-handling moved to cdrom_id: The tray
37 is locked as soon as a media is detected to enable the receiving
38 of media-eject-request events. Media-eject-request events will
41 Libudev enumerate is now able to enumerate a subtree of a given
44 The mobile-action-modeswitch modeswitch tool was deleted. The
45 functionality is provided by usb_modeswitch now.
51 The systemd service files require systemd version 28. The systemd
52 socket activation make it possible now to start 'udevd' and 'udevadm
57 Fix bug in control message handling, which can lead to a failing
58 udevadm control --exit. Thanks to Jürg Billeter for help tracking
65 We require at least Linux kernel 2.6.32 now. Some platforms might
66 require a later kernel that supports accept4() and similar, or
67 need to backport the trivial syscall wiring to the older kernels.
69 The hid2hci tool moved to the bluez package and was removed.
71 Many of the extras can be --enable/--disabled at ./configure
72 time. The --disable-extras option was removed. Some extras have
73 been disabled by default. The current options and their defaults
74 can be checked with './configure --help'.
80 Udev logs a warning now if /run is not writable at udevd
81 startup. It will still fall back to /dev/.udev, but this is
84 The running udev daemon can now cleanly shut down with:
85 udevadm control --exit
87 Udev in initramfs should clean the state of the udev database
88 with: udevadm info --cleanup-db which will remove all state left
89 behind from events/rules in initramfs. If initramfs uses
90 --cleanup-db and device-mapper/LVM, the rules in initramfs need
91 to add OPTIONS+="db_persist" for all dm devices. This will
92 prevent removal of the udev database for these devices.
94 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
95 120 seconds per process. If that timeout is reached the spawned
96 process will be killed. The event timeout can be overwritten with
99 If systemd is used, udev gets now activated by netlink data.
100 Systemd will bind the netlink socket which will buffer all data.
101 If needed, such setup allows a seemless update of the udev daemon,
102 where no event can be lost during a udevd update/restart.
103 Packages need to make sure to: systemctl stop udev.socket udev.service
104 or 'mask' udev.service during the upgrade to prevent any unwanted
105 auto-spawning of udevd.
106 This version of udev conflicts with systemd version below 25. The
107 unchanged service files will not wirk correctly.
113 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
114 /run mountpoint is supposed to be a tmpfs mounted during early boot,
115 available and writable to for all tools at any time during bootup,
116 it replaces /var/run/, which should become a symlink some day.
118 If /run does not exist, or is not writable, udev will fall back using
121 On systemd systems with initramfs and LVM used, packagers must
122 make sure, that the systemd and initramfs versions match. The initramfs
123 needs to create the /run mountpoint for udev to store the data, and
124 mount this tmpfs to /run in the rootfs, so the that the udev database
125 is preserved for the udev version started in the rootfs.
127 The command 'udevadm info --convert-db' is gone. The udev daemon
128 itself, at startup, converts any old database version if necessary.
130 The systemd services files have been reorganized. The udev control
131 socket is bound by systemd and passed to the started udev daemon.
132 The udev-settle.service is no longer active by default. Services which
133 can not handle hotplug setups properly need to actively pull it in, to
134 act like a barrier. Alternatively the settle service can be unconditionally
135 'systemctl'enabled, and act like a barrier for basic.target.
137 The fstab_import callout is no longer built or installed. Udev
138 should not be used to mount, does not watch changes to fstab, and
139 should not mirror fstab values in the udev database.
145 New and updated keymaps.
151 The udev database has changed, After installation of a new udev
152 version, 'udevadm info --convert-db' should be called, to let the new
153 udev/libudev version read the already stored data.
155 udevadm now supports quoting of property values, and prefixing of
157 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
160 MY_DEVNAME='/dev/sda'
164 libudev now supports:
165 udev_device_get_is_initialized()
166 udev_enumerate_add_match_is_initialized()
167 to be able to skip devices the kernel has created , but udev has
170 libudev now supports:
171 udev_device_get_usec_since_initialized()
172 to retrieve the "age" of a udev device record.
174 GUdev supports a more generic GUdevEnumerator class, udev TAG
175 handling, device initialization and timestamp now.
177 The counterpart of /sys/dev/{char,block}/$major:$minor,
178 /dev/{char,block}/$major:$minor symlinks are now unconditionally
179 created, even when no rule files exist.
181 New and updated keymaps.
187 GUdev moved from /usr to /.
197 Persistent network naming rules are disabled inside of Qemu/KVM now.
199 New and updated keymaps.
201 Udev gets unconditionally enabled on systemd installations now. There
202 is no longer the need to to run 'systemctl enable udev.service'.
216 New and fixed keymaps.
218 Install systemd service files if applicable.
224 All distribution specific rules are removed from the udev source tree,
225 most of them are no longer needed. The Gentoo rules which allow to support
226 older kernel versions, which are not covered by the default rules anymore
227 has moved to rules/misc/30-kernel-compat.rules.
233 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
234 was removed from udevd.
236 Udevd now checks the kernel commandline for the following variables:
237 udev.log-priority=<syslog priority>
238 udev.children-max=<maximum number of workers>
239 udev.exec-delay=<seconds to delay the execution of RUN=>
240 to help debuging coldplug setups where the loading of a kernel
241 module crashes the system.
243 The subdirectory in the source tree rules/packages has been renamed to
244 rules/arch, anc contains only architecture specific rules now.
254 Now the udev daemon itself, does on startup:
255 - copy the content of /lib/udev/devices to /dev
256 - create the standard symlinks like /dev/std{in,out,err},
257 /dev/core, /dev/fd, ...
258 - use static node information provided by kernel modules
259 and creates these nodes to allow module on-demand loading
260 - possibly apply permissions to all ststic nodes from udev
261 rules which are annotated to match a static node
263 The default mode for a device node is 0600 now to match the kernel
264 created devtmpfs defaults. If GROUP= is specified and no MODE= is
265 given the default will be 0660.
271 Udev now gradually starts to pass control over the primary device nodes
272 and their names to the kernel, and will in the end only manage the
273 permissions of the node, and possibly create additional symlinks.
274 As a first step NAME="" will be ignored, and NAME= setings with names
275 other than the kernel provided name will result in a logged warning.
276 Kernels that don't provide device names, or devtmpfs is not used, will
277 still work as they did before, but it is strongly recommended to use
278 only the same names for the primary device node as the recent kernel
279 provides for all devices.
283 Fix broken firmware loader search path.
289 "udevadm trigger" defaults to "change" events now instead of "add"
290 events. The "udev boot script" might need to add "--action=add" to
291 the trigger command if not already there, in case the initial coldplug
292 events are expected as "add" events.
294 The option "all_partitons" was removed from udev. This should not be
295 needed for usual hardware. Udev can not safely make assumptions
296 about non-existing partition major/minor numbers, and therefore no
297 longer provide this unreliable and unsafe option.
299 The option "ignore_remove" was removed from udev. With devtmpfs
300 udev passed control over device nodes to the kernel. This option
301 should not be needed, or can not work as advertised. Neither
302 udev nor the kernel will remove device nodes which are copied from
303 the /lib/udev/devices/ directory.
305 All "add|change" matches are replaced by "!remove" in the rules and
306 in the udev logic. All types of events will update possible symlinks
307 and permissions, only "remove" is handled special now.
309 The modem modeswitch extra was removed and the external usb_modeswitch
310 program should be used instead.
312 New and fixed keymaps.
322 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
323 depend on the current sysfs layout and the information not available in the
324 deprecated layout. All remaining support for the deprecated sysfs layout is
329 Fix for a possible endless loop in the new input_id program.
335 The option "ignore_device" does no longer exist. There is no way to
336 ignore an event, as libudev events can not be suppressed by rules.
337 It only prevented RUN keys from being executed, which results in an
338 inconsistent behavior in current setups.
340 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
341 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
344 The support for the deprecated IDE devices has been removed from the
345 default set of rules. Distros who still care about non-libata drivers
346 need to add the rules to the compat rules file.
348 The ID_CLASS property on input devices has been replaced by the more accurate
349 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
350 determined by the new "input_id" prober now. Some devices, such as touchpads,
351 can have several classes. So if you previously had custom udev rules which e. g.
352 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
353 ENV{ID_INPUT_KEYBOARD}=="?*".
359 To support DEVPATH strings larger than the maximum file name length, the
360 private udev database format has changed. If some software still reads the
361 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
362 Please do not port anything to the new format again, everything in /dev/.udev
363 is and always was private to udev, and may and will change any time without
366 Multiple devices claiming the same names in /dev are limited to symlinks
367 only now. Mixing identical symlink names and node names is not supported.
368 This reduces the amount of data in the database significantly.
370 NAME="%k" causes a warning now. It's is and always was completely superfluous.
371 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
374 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
375 if they are not the default. To support older kernels, the NAME= rules need to
376 be added to the compat rules file.
378 Symlinks to udevadm with the old command names are no longer resolved to
379 the udevadm commands.
381 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
384 The option "last_rule" does no longer exist. Its use breaks too many
385 things which expect to be run from independent later rules, and is an idication
386 that something needs to be fixed properly instead.
388 The gudev API is no longer marked as experimental,
389 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
390 is enabled by default now. Various projects already depend on introspection
391 information to bind dynamic languages to the gudev interfaces.
397 The udevadm trigger "--retry-failed" option, which is replaced since quite
398 a while by "--type=failed" is removed.
400 The failed tracking was not working at all for a few releases. The RUN
401 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
402 default is not to track any failing RUN executions.
404 New keymaps, new modem, hid2hci updated.
408 Fix possible crash in udevd when worker processes are busy, rules are
409 changed at the same time, and workers get killed to reload the rules.
415 Properties set with ENV{.FOO}="bar" are marked private by starting the
416 name with a '.'. They will not be stored in the database, and not be
417 exported with the event.
419 Firmware files are looked up in:
420 /lib/firmware/updates/$(uname -r)
421 /lib/firmware/updates
422 /lib/firmware/$(uname -r)
426 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
427 ata_id, instead of scsi_id, is the default tool now for ATA devices.
433 The configure options have changed because another library needs to be
434 installed in a different location. Instead of exec_prefix and udev_prefix,
435 libdir, rootlibdir and libexecdir are used. The Details are explained in
438 Event processes now get re-used after they handled an event. This reduces
439 the number of forks and the pressure on the CPU significantly, because
440 cloned event processes no longer cause page faults in the main daemon.
441 After the events have settled, a few worker processes stay around for
442 future events, all others get cleaned up.
444 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
445 Also inotify support is mandatory now to run udev.
447 The format of the queue exported by the udev damon has changed. There is
448 no longer a /dev/.udev/queue/ directory. The current event queue can be
449 accessed with udevadm settle and libudedv.
451 Libudev does not have the unstable API header anymore. From now on,
452 incompatible changes will be handled by bumping the library major version.
454 To build udev from the git tree gtk-doc is needed now. The tarballs will
455 build without it and contain the pre-built documentation. An online copy
457 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
459 The tools from the udev-extras repository have been merged into the main
460 udev repository. Some of the extras have larger external dependencies, and
461 they can be disabled with the configure switch --disable-extras.
467 The program vol_id and the library libvolume_id are removed from the
468 repository. Libvolume_id is merged with libblkid from the util-linux-ng
469 package. Persistent disk links for label and uuid depend on the
470 util-linux-ng version (2.15) of blkid now. Older versions of blkid
471 can not be used with udev.
473 Libudev allows to subscribe to udev events. To prevent unwanted messages
474 to be delivered, and waking up the subscribing process, a filter can be
475 installed, to drop messages inside a kernel socket filter. The filters
476 match on the <subsytem>:<devtype> properties of the device.
477 This is part of the ongoing effort to replace HAL, and switch current
478 users over to directly use libudev.
479 Libudev is still marked as experimental, and its interface might
480 eventually change if needed, but no major changes of the currently exported
481 interface are expected anymore, and a first stable release should happen
484 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
485 is not supported since while and udevd will log an error message at
486 startup. It should still be able to boot-up, but advanced rules and system
487 services which depend on the information not available in the old sysfs
488 format will fail to work correctly.
490 DVB device naming is supplied by the kernel now. In case older kernels
491 need to be supported, the old shell script should be added to a compat
498 The processed udev events get send back to the netlink socket. Libudev
499 provides access to these events. This is work-in-progress, to replace
500 the DeviceKit daemon functionality directly with libudev. There are
501 upcoming kernel changes to allow non-root users to subcribe to these
508 "udevadm settle" now optionally accepts a range of events to wait for,
509 instead of waiting for "all" events.
515 The installed watch for block device metadata changes is now removed
516 during event hadling, because some (broken) tools may be called from udev
517 rules and (wrongly) open the device with write access. After the finished
518 event handling the watch is restored.
524 Device nodes can be watched for changes with inotify with OPTIONS="watch".
525 If closed after being opened for writing, a "change" uevent will occur.
526 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
532 The udevadm test command has no longer a --force option, nodes and symlinks
533 are always updated with a test run now.
535 The udevd daemon can be started with --resolve-names=never to avoid all user
536 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
537 lookup user and groups every time events are handled.
543 We are currently merging the Ubuntu rules in the udev default rules,
544 and get one step closer to provide a common Linux /dev setup, regarding
545 device names, symlinks, and default device permissions. On udev startup,
546 we now expect the following groups to be resolvable to their ids with
548 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
549 LDAP setups need to make sure, that these groups are always resolvable at
550 bootup, with only the rootfs mounted, and without network access available.
552 Some systems may need to add some new, currently not used groups, or need
553 to add some users to new groups, but the cost of this change is minimal,
554 compared to the pain the current, rather random, differences between the
555 various distributions cause for upstream projects and third-party vendors.
557 In general, "normal" users who log into a machine should never be a member
558 of any such group, but the device-access should be managed by dynamic ACLs,
559 which get added and removed for the specific users on login/logout and
560 session activity/inactivity. These groups are only provided for custom setups,
561 and mainly system services, to allow proper privilege separation.
562 A video-streaming daemon uid would be a member of "audio" and "video", to get
563 access to the sound and video devices, but no "normal" user should ever belong
564 to the "audio" group, because he could listen to the built-in microphone with
565 any ssh-session established from the other side of the world.
567 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
568 which do not depend on the kernel device name. As usual, unique
569 devices - only a single one per product connected, or a real
570 USB serial number in the device - are always found with the same
571 name in the by-id/ directory.
572 Completely identical devices may overwrite their names in by-id/
573 and can only be found reliably in the by-path/ directory. Devices
574 specified by by-path/ must not change their connection, like the
575 USB port number they are plugged in, to keep their name.
577 To support some advanced features, Linux 2.6.22 is the oldest supported
578 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
579 supported. Older kernels should still work, and devices nodes should be
580 reliably created, but some rules and libudev will not work correctly because
581 the old kernels do not provide the expected information or interfaces.
587 Fix for a possible segfault while swapping network interface names in udev
594 The group "video" is part of the default rules now.
598 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
599 block devices in some cases. No common distro uses this option anymore,
600 and we do not get enough testing for this and recent udev versions. If
601 this option is not needed to run some old distro with a new kernel,
602 it should be disabled in the kernel config.
604 Bugfix for the $links substitution variable, which may crash if no links
605 are created. This should not happen in usual setups because we always
606 create /dev/{block,char}/ links.
608 The strings of the parsed rules, which are kept in memory, no longer
609 contain duplicate entries, or duplicate tails of strings. This, and the
610 new rules parsing/matching code reduces the total in-memory size of
611 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
614 The export of DEVTYPE=disk/partition got removed from the default
615 rules. This value is available from the kernel. The pnp shell script
616 modprobe hack is removed from the default rules. ACPI devices have _proper_
617 modalias support and take care of the same functionality.
618 Installations which support old kernels, but install current default
619 udev rules may want to add that to the compat rules file.
621 Libvolume_id now always probes for all known filesystems, and does not
622 stop at the first match. Some filesystems are marked as "exclusive probe",
623 and if any other filesytem type matches at the same time, libvolume_id
624 will, by default, not return any probing result. This is intended to prevent
625 mis-detection with conflicting left-over signatures found from earlier
626 file system formats. That way, we no longer depend on the probe-order
627 in case of multiple competing signatures. In some setups the kernel allows
628 to mount a volume with just the old filesystem signature still in place.
629 This may damage the new filesystem and cause data-loss, just by mounting
630 it. Because volume_id can not decide which one the correct signature is,
631 the wrong signatures need to be removed manually from the volume, or the
632 volume needs to be reformatted, to enable filesystem detection and possible
637 Fix segfault if compiled without optimization and dbg() does not get
638 compiled out and uses variables which are not available.
642 Bugfixes. (And maybe new bugs. :))
644 The rule matching engine got converted from a rule list to a token
645 array which reduced the in-memory rules representation of a full
646 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
647 Limits like 5 ENV and ATTR matches, and one single instance for most
648 other keys per rule are gone.
650 The NAME assignment is no longer special cased. If later rules assign
651 a NAME value again, the former value will be overwritten. As usual
652 for most other keys, the NAME value can be protected by doing a final
653 assignment with NAME:="<value>".
655 All udev code now uses libudev, which is also exported. The library
656 is still under development, marked as experimental, and its interface
657 may change as long as the DeviceKit integration is not finished.
659 Many thanks to Alan Jenkins for his continuous help, and finding and
660 optimizing some of the computing expensive parts.
666 Kernel devices and device nodes are connected now by reverse indizes in
667 /sys and /dev. A device number retrieved by a stat() or similar, the
668 kernel device directory can be found by looking up:
669 /sys/dev/{block,char}/<maj>:<min>
670 and the device node of the same device by looking up:
671 /dev/{block,char}/<maj>:<min>
675 Fix recently introduced bug, which caused a compilation without large
676 file support, where vol_id does not recognize raid signatures at the end
679 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
680 Seems some kernel versions prevent the creation of the ieee-* links,
681 so people used the scsi-* link which disappeared now.
683 More libudev work. Almost all udevadm functionality comes from libudev
686 udevadm trigger has a new option --type, which allows to trigger events
687 for "devices", for "subsystems", or "failed" devices. The old option
688 --retry-failed" still works, but is no longer mentioned in the man page.
694 The udevadm info --device-id-of-file= output has changed to use
695 the obvious format. Possible current users should use the --export
696 option which is not affected.
698 The old udev commands symlinks to udevadm are not installed, if
699 these symlinks are used, a warning is printed.
705 Optical drive's media is no longer probed for raid signatures,
706 reading the end of the device causes some devices to malfunction.
707 Also the offset of the last session found is used now to probe
710 The volume_id library got a major version number update to 1,
711 some deprecated functions are removed.
713 A shared library "libudev" gets installed now to provide access
714 to udev device information. DeviceKit, the successor of HAL, will
715 need this library to access the udev database and search sysfs for
717 The library is currently in an experimental state, also the API is
718 expected to change, as long as the DeviceKit integration is not
723 We use ./configure now. See INSTALL for details. Current
726 "/usr" - prefix for man pages, include files
728 "" - the root filesystem, prefix for libs and binaries
732 "lib" - directory name for libraries, not a path name
733 multilib 64bit systems may use "lib64" instead of "lib"
735 compile-in verbose debug messages
737 disable all logging and compile-out all log strings
739 link against SELInux libraries, to set the expected context
742 In the default rules, the group "disk" gets permissions 0660 instead
743 of 0640. One small step closer to unify distro rules. Some day, all
744 distros hopefully end up with the same set of rules.
746 No symlinks to udevadm are installed anymore, if they are still needed,
747 they should be provided by the package.
753 Default udev rules, which are not supposed to be edited by the user, should
754 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
755 the udev package and will be replaced with an update. Udev will pick up rule
757 /lib/udev/rules.d/ - default installed rules
758 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
759 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
760 It does not matter in which directory a rule file lives, all files are sorted
763 To help creating /dev/root, we have now:
764 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
767 In case the current --device-id-of-file is already used, please switch to
768 the --export format version, it saves the output parsing and the old
769 format will be changed to use ':' as a separator, like the format in the
774 Fix cdrom_id to properly recognize blank media.
780 Tape drive id-data is queried from /dev/bsg/* instead of the tape
781 nodes. This avoids rewinding tapes on open().
787 The symlinks udevcontrol and udevtrigger are no longer installed by
790 The scsi_id program does not depend on sysfs anymore. It can speak
791 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
792 data, which should solve some old problems with tape devices, where
793 we better do not open all tape device nodes to identify the device.
799 The cdrom_id program is replaced by an advanced version, which can
800 detect most common device types, and also properties of the inserted
801 media. This is part of moving some basic functionality from HAL into
802 udev (and the kernel).
808 The last WAIT_FOR_SYSFS rule is removed from the default rules.
810 The symlinks to udevadm for the debugging tools: udevmonitor and
811 udevtest are no longer created.
813 The symlinks to the udevadm man page for the old tool names are
816 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
817 should be prefixed with '@' to indicate that the path is not a
828 Udevstart is removed from the tree, it did not get installed for
829 a long time now, and is long replaced by trigger and settle.
835 All udev tools are merged into a single binary called udevadm.
836 The old names of the tools are built-in commands in udevadm now.
837 Symlinks to udevadm, with the names of the old tools, provide
838 the same functionality as the standalone tools. There is also
839 only a single udevadm.8 man page left for all tools.
841 Tools like mkinitramfs should be checked, if they need to include
842 udevadm in the list of files.
852 The etc/udev/rules.d/ directory now contains a default set of basic
853 udev rules. This initial version is the result of a rules file merge
854 of Fedora and openSUSE. For these both distros only a few specific
855 rules are left in their own file, named after the distro. Rules which
856 are optionally installed, because they are only valid for a specific
857 architecture, or rules for subsystems which are not always used are
858 in etc/udev/packages/.
864 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
865 actions by dynamically created rules.
867 SYMLINK=="<value>" matches agains the entries in the list of
868 currently defined symlinks. The links are not created in the
869 filesystem at that point in time, but the values can be matched.
871 RUN{ignore_error}+="<program>" will ignore any exit code from the
872 program and not record as a failed event.
878 Final merge of patches/features from the Ubuntu package.
884 Control characters in filesystem label strings are no longer silenty
885 removed, but hex-encoded, to be able to uniquely identify the device
886 by its symlink in /dev/disk/by-label/.
887 If libvolume_id is used by mount(8), LABEL= will work as expected,
888 if slashes or other characters are used in the label string.
890 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
891 can be specified now. The TEST key accepts an optional mode mask
892 TEST{0100}=="<is executable file>".
894 Scsi_id now supports a mode without expecting scsi-specific sysfs
895 entries to allow the extraction of cciss-device persistent properties.
901 In the future, we may see uuid's which are just simple character
902 strings (see the DDF Raid Specification). For that reason vol_id now
903 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
904 the creation of symlinks, the *_SAFE values ensure, that no control
905 or whitespace characters are used in the filename.
907 Possible users of libvolume_id, please use the volume_id_get_* functions.
908 The public struct will go away in a future release of the library.
914 Removal of useless extras/eventrecorder.sh.
924 The directory multiplexer for dev.d/ and hotplug.d are finally removed
925 from the udev package.
931 Symlinks can have priorities now, the priority is assigned to the device
932 and specified with OPTIONS="link_priority=100". Devices with higher
933 priorities overwrite the symlinks of devices with lower priorities.
934 If the device that currently owns the link, goes away, the symlink
935 will be removed, and recreated, pointing to the next device with the
936 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
937 more reliable, if multiple devices contain the same metadata and overwrite
940 The dasd_id program is removed from the udev tree, and dasdinfo, with the
941 needed rules, are part of the s390-tools now.
943 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
944 we may get the scsi sysfs mess fixed some day, and this will only catch
945 the devices we are looking for.
947 USB serial numbers for storage devices have the target:lun now appended,
948 to make it possibble to distinguish broken multi-lun devices with all
949 the same SCSI identifiers.
951 Note: The extra "run_directory" which searches and executes stuff in
952 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
953 with the next release. Make sure, that you don't use it anymore, or
954 provides your own implementation of that inefficient stuff.
955 We are tired of reports about a "slow udev", because these directories
956 contain stuff, that runs with _every_ event, instead of using rules,
957 that run programs only for the matching events.
967 DRIVER== will match only for devices that actually have a real
968 driver. DRIVERS== must be used, if parent devices should be
969 included in the match.
971 Libvolume_id's "linux_raid" detection needed another fix.
979 Add additional check to volume_id detection of via_raid, cause
980 some company decided to put a matching pattern all over the empty
981 storage area of their music players.
985 Fix path_id for SAS devices.
989 The udev daemon can be started with --debug-trace now, which will
990 execute all events serialized to get a chance to catch a possible
991 action that crashes the box.
993 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
994 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
995 are excluded from the warning. Referencing parent attributes directly
996 may break when something in the kernel driver model changes. Udev will
997 just find the attribute by walking up the parent chain.
999 Udevtrigger now sorts the list of devices depending on the device
1000 dependency, so a "usb" device is triggered after the parent "pci"
1005 Revert persistent-storage ata-serial '_' '-' replacement.
1011 Udevtrigger can now filter the list of devices to be triggered. Matches
1012 for subsystems or sysfs attributes can be specified.
1014 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1015 zero-sized files to avoid pointing to /sys and confuse broken tools which
1016 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1019 The rules and scripts to create udev rules for persistent network
1020 devices and optical drives are in the extras/rules_generator directory
1021 now. If you use something similar, please consider replacing your own
1022 version with this, to share the support effort. The rule_generator
1023 installs its own rules into /etc/udev/rules.d.
1025 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1026 the rule_generator depends on cdrom_id to be called in an earlier rule.
1032 Renaming of some key names (the old names still work):
1033 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1034 (The behavior of the key DRIVER will change soon in one of the next
1035 releases, to match only the event device, please switch to DRIVERS
1036 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1038 With the new key names, we have a more consistent and simpler scheme.
1039 We can match the properties of the event device only, with: KERNEL,
1040 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1041 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1042 longer mentioned in the man page and should be switched in the rule
1045 ATTR{file}="value" can be used now, to write to a sysfs file of the
1046 event device. Instead of:
1047 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1049 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1051 All the PHYSDEV* keys are deprecated and will be removed from a
1053 PHYDEVPATH - is the path of a parent device and should not be
1055 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1056 matched with SUBSYSTEMS==
1057 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1058 Newer kernels will have DRIVER in the environment,
1059 for older kernels udev puts in. Class device will
1060 no longer carry this property of a parent and
1061 DRIVERS== can be used to match such a parent value.
1062 Note that ENV{DRIVER} is only available for a few bus devices, where
1063 the driver is already bound at device event time. On coldplug, the
1064 events for a lot devices are already bound to a driver, and they will have
1065 that value set. But on hotplug, at the time the kernel creates the device,
1066 it can't know what driver may claim the device after that, therefore
1067 in most cases it will be empty.
1069 Failed events should now be re-triggered with:
1070 udevtrigger --retry-failed.
1071 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1072 files private to the udev tools. We may need to switch the current symlink
1073 target, cause some obviously broken tools try to scan all files in /dev
1074 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1075 million times. This takes ages on slow boxes.
1077 The udevinfo attribute walk (-a) now works with giving a device node
1078 name (-n) instead of a devpath (-p). The query now always works, also when
1079 no database file was created by udev.
1081 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1082 getpwnam() and getgrnam() now. One of the next releases will depend on
1083 fnmatch() and may use getopt_long().
1087 Bugfixes and small improvements.
1091 Fix path_id for recent kernels.
1097 Added support for swapping network interface names, by temporarily
1098 renaming the device and wait for the target name to become free.
1102 The built-in MODALIAS key and substitution is removed.
1106 The binary firmware helper is replaced by the usual simple
1107 shell script. Udevsend is removed from the tree.
1115 Some more keys require the correct use of '==' and '=' depending
1116 on the kind of operation beeing an assignment or a match. Rules
1117 with invalid operations are skipped and logged to syslog. Please
1118 test with udevtest if the parsing of your rules throws errors and
1119 fix possibly broken rules.
1123 Provide "udevsettle" to wait for all current udev events to finish.
1124 It also watches the current kernel netlink queue by comparing the
1125 even sequence number to make sure that there are no current pending
1126 events that have not already arrived in the daemon.
1130 Fix rule to skip persistent rules for removable IDE devices, which
1131 also skipped optical IDE drives.
1133 All *_id program are installed in /lib/udev/ by default now.
1135 No binary is stripped anymore as this should be done in the
1136 packaging process and not at build time.
1138 libvolume_id is provided as a shared library now and vol_id is
1139 linked against it. Also one of the next HAL versions will require
1140 this library, and the HAL build process will also require the
1141 header file to be installed. The copy of the same code in HAL will
1142 be removed to have only a single copy left on the system.
1146 Add persistent links for SCSI tapes. The rules file is renamed
1147 to 60-persistent-storage.rules.
1149 Create persistent path for usb devices. Can be used for all sorts
1150 of devices that can't be distinguished by other properties like
1151 multiple identical keyboards and mice connected to the same box.
1153 Provide "udevtrigger" program to request events on coldplug. The
1154 shell script is much too slow with thousends of devices.
1158 Fix persistent disk rules to exclude removable IDE drives.
1160 Warn if %e, $modalias or MODALIAS is used.
1164 Fix queue export, which wasn't correct for subsequent add/remove
1165 events for the same device.
1169 Fix cramfs detection on big endian.
1171 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1176 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1177 attributes were only checked at the parent device that matched the
1178 by BUS requested subsystem. Fix it to also look at the device we
1179 received the event for.
1181 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1186 Fix a bug where NAME="" would prevent RUN from beeing executed.
1188 RUN="/bin/program" does not longer automatically add the subsystem
1189 as the first parameter. This is from the days of /sbin/hotplug
1190 which is dead now and it's just confusing to need to add a space at
1191 the end of the program name to prevent this.
1192 If you use rules that need the subsystem as the first parameter,
1193 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1194 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1198 The udev man page has moved to udev(7) as it does not describe a command
1199 anymore. The programs udev, udevstart and udevsend are no longer installed
1200 by default and must be copied manually, if they should be installed or
1201 included in a package.
1203 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1204 the ignore rule was applied.
1206 More preparation for future sysfs changes. usb_id and scsi_id no longer
1207 depend on a magic order of devices in the /devices chain. Specific devices
1208 should be requested by their subsytem.
1210 This will always find the scsi parent device without depending on a specific
1212 dev = sysfs_device_get(devpath);
1213 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1215 The "device" link in the current sysfs layout will be automatically
1216 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1217 parent in the devpath. If a device is requested by it's symlink, like all
1218 class devices in the new sysfs layout will look like, it gets automatically
1219 resolved and substituted with the real devpath and not the symlink path.
1222 A similar logic must be applied to _all_ sysfs users, including
1223 scripts, that search along parent devices in sysfs. The explicit use of
1224 the "device" link must be avoided. With the future sysfs layout all
1225 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1226 back to the "class" or the "bus". The layout of the parent devices in
1227 /devices is not necessarily expected to be stable across kernel releases and
1228 searching for parents by their subsystem should make sysfs users tolerant
1229 for changed parent chains.
1233 Prepare udev to work with the experimental kernel patch, that moves
1234 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1236 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1237 moving the class devices to /sys/devices.
1239 Thanks again to Marco for help finding a hopefully nice compromise
1240 to make %b simpler and working again.
1244 Complete removal of libsysfs, replaced by simple helper functions
1245 which are much simpler and a bit faster. The udev daemon operatesentirely
1246 on event parameters and does not use sysfs for simple rules anymore.
1247 Please report any new bugs/problems, that may be caused by this big
1248 change. They will be fixed immediately.
1250 The enumeration format character '%e' is deprecated and will be
1251 removed sometimes from a future udev version. It never worked correctly
1252 outside of udevstart, so we can't use it with the new parallel
1253 coldplug. A simple enumeration is as useless as the devfs naming
1254 scheme, just get rid of both if you still use it.
1256 MODALIAS and $modalias is not needed and will be removed from one of
1257 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1258 the sysfs "modalias" value.
1260 Thanks a lot to Marco for all his help on finding and fixing bugs.
1264 Let scsi_id request libata drive serial numbers from page 0x80.
1266 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1267 added /dev/disk/by-name/* for device mapper device names.
1269 Removed %e from the man page. It never worked reliably outside
1270 of udevstart and udevstart is no longer recommended to use.
1274 Symlinks are now exported to the event environment. Hopefully it's no
1275 longer needed to run udevinfo from an event process, like it was
1276 mentioned on the hotplug list:
1277 UDEV [1134776873.702967] add@/block/sdb
1280 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1284 Fix a problem if udevsend is used as the hotplug handler and tries to use
1285 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1286 and this kind of problems will hopefully go away soon.
1290 All built-in logic to work around bad sysfs timing is removed with this
1291 version. The need to wait for sysfs files is almost fixed with a kernel
1292 version that doesn't work with this udev version anyway. Until we fix
1293 the timing of the "bus" link creation, the former integrated logic should
1294 be emulated by a rule placed before all other rules:
1295 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1297 The option "udev_db" does no longer exist. All udev state will be in
1298 /$udev_root/.udev/ now, there is no longer an option to set this
1300 If the init script or something else used this value, just depend on
1301 this hardcoded path. But remember _all_content_ of this directory is
1302 still private to udev and can change at any time.
1304 Default location for rule sripts and helper programs is now: /lib/udev/.
1305 Everything that is not useful on the commandline should go into this
1306 directory. Some of the helpers in the extras folder are installed there
1307 now. The rules need to be changed, to find the helpers there.
1309 Also /lib/udev/devices is recommended as a directory where packages or
1310 the user can place real device nodes, which get copied over to /dev at
1311 every boot. This should replace the various solutions with custom config
1314 Udevsend does no longer start the udev daemon. This must be done with
1315 the init script that prepares /dev on tmpfs and creates the initial nodes,
1316 before starting the daemon.
1320 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1323 The copy of klibc is removed. A systemwide installed version of klibc
1324 should be used to build a klibc udev now.
1328 NAME="" will not create any nodes, but execute RUN keys. To completely
1329 ignore an event the OPTION "ignore_device" should be used.
1331 After removal of the reorder queue, events with a TIMEOUT can be executed
1332 without any queuing now.
1336 Fixed bug in udevd, if inotify is not available. We depend on netlink
1337 uevents now, kernels without that event source will not work with that
1338 version of udev anymore.
1342 The rule parsing happens now in the daemon once at startup, all udev
1343 event processes inherit the already parsed rules from the daemon.
1344 It is shipped with SUSE10.0 and reduces heavily the system load at
1345 startup. The option to save precompiled rules and let the udev process
1346 pick the them up is removed, as it's no longer needed.
1348 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1349 device. Libsysfs is changed to "translate" the requested link into the
1350 real device path, as it would happen with the hotplug event. Otherwise
1351 device removal and the udev database will not work.
1353 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1356 A few improvements for vol_id, the filesytem probing code.
1360 Fix a stupid typo in extras/run_directory for "make install".
1362 scsi_id creates the temporary devnode now in /dev for usage with a
1363 non-writable /tmp directory.
1365 The uevent kernel socket buffer can carry app. 50.000 events now,
1366 let's see who can break this again. :)
1368 The upcoming kernel will have a new input driver core integration.
1369 Some class devices are now symlinks to the real device. libsysfs
1370 needs a fix for this to work correctly. Udevstart of older udev
1371 versions will _not_ create these devices!
1375 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1380 A bunch of mostly trivial bugfixes. From now on no node name or
1381 symlink name can contain any character than plain whitelisted ascii
1382 characters or validated utf8 byte-streams. This is needed for the
1383 /dev/disk/by-label/* links, because we import untrusted data and
1384 export it to the filesystem.
1388 More bugfixes. If udevd was started from the kernel, we don't
1389 have stdin/stdout/stderr, which broke the forked tools in some
1394 Bugfix. udevstart event ordering was broken for a long time.
1395 The new run_program() uncovered it, because /dev/null was not
1396 available while we try to run external programs.
1397 Now udevstart should create it before we run anything.
1401 Minor bugfixes and some distro rules updates. If you don't have the
1402 persistent disk rules in /dev/disk/by-*/* on your distro, just
1403 grab it from here. :)
1407 We can use socket communication now to pass events from udev to
1409 RUN+="socket:/org/freedesktop/hal/udev_event"
1410 will pass the whole udev event to the HAL daemon without the need
1411 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1415 Mostly bugfixes and see ChangeLog.
1417 The test for the existence of an environment value should be
1419 ENV{KEY}=="*" to ENV{KEY}=="?*"
1420 because "*" will not fail anymore, if the key does not exist or
1425 Bugfixes and a few tweaks described in the ChangeLog.
1429 Mostly a Bugfix release.
1431 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1432 timing with custom rules.
1436 We changed the internal rule storage format. Our large rule files took
1437 2 MB of RAM, with the change we are down to 99kB.
1439 If the device-node has been created with default name and no symlink or
1440 options are to remenber, it is not longer stored in the udevdb. HAL will
1441 need to be updated to work correctly with that change.
1443 To overrride optimization flags, OPTFLAGS may be used now.
1451 Major changes happened with this release. The goal is to take over the
1452 complete kernel-event handling and provide a more efficient way to dispatch
1453 kernel events. Replacing most of the current shell script logic and the
1454 kernel forked helper with a netlink-daemon and a rule-based event handling.
1456 o udevd listens to netlink events now. The first valid netlink event
1457 will make udevd ignore any message from udevsend that contains a
1458 SEQNUM, to avoid duplicate events. The forked events can be disabled
1460 echo "" > /proc/sys/kernel/hotplug
1461 For full support, the broken input-subsytem needs to be fixed, not to
1462 bypass the driver core.
1464 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1465 removed from udev itself and must be emulated by calling small
1466 helper binaries provided in the extras folder:
1467 make EXTRAS=extras/run_directory/
1468 will build udev_run_devd and udev_run_hotplugd, which can be called
1469 from a rule if needed:
1470 RUN+="/sbin/udev_run_hotplugd"
1471 The recommended way to handle this is to convert all the calls from
1472 the directories to explicit udev rules and get completely rid of the
1473 multiplexing. (To catch a ttyUSB event, you now no longer need to
1474 fork and exit 300 tty script instances you are not interested in, it
1475 is just one rule that matches exactly the device.)
1477 o udev handles now _all_ events not just events for class and block
1478 devices, this way it is possible to control the complete event
1479 behavior with udev rules. Especially useful for rules like:
1480 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1482 o As used in the modalias rule, udev supports now textual
1483 substitution placeholder along with the usual format chars. This
1484 needs to be documented, for now it's only visible in udev_rules_parse.c.
1486 o The rule keys support now more operations. This is documented in the
1487 man page. It is possible to add values to list-keys like the SYMLINK
1488 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1489 Also "final"-assignments are supported by using KEY:="value", which will
1490 prevent changing the key by any later rule.
1492 o kernel 2.6.12 has the "detached_state" attribute removed from
1493 sysfs, which was used to recognize sysfs population. We switched that
1494 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1495 Running this udev version on older kernels may cause a short delay for
1498 o To provide infrastructure for persistent device naming, the id programs:
1499 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1500 to export the probed data in environment key format:
1501 pim:~ # /sbin/ata_id --export /dev/hda
1502 ID_MODEL=HTS726060M9AT00
1503 ID_SERIAL=MRH401M4G6UM9B
1504 ID_REVISION=MH4OA6BA
1506 The following rules:
1507 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1508 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1511 kay@pim:~> tree /dev/disk
1514 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1515 | `-- IBM-Memory_Key -> ../../sda
1517 | |-- swap -> ../../hda1
1518 | |-- date -> ../../sda1
1519 | `-- home -> ../../hda3
1521 |-- 2E08712B0870F2E7 -> ../../hda3
1522 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1523 |-- E845-7A89 -> ../../sda1
1524 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1526 The IMPORT= operation will import these keys in the environment and make
1527 it available for later PROGRAM= and RUN= executed programs. The keys are
1528 also stored in the udevdb and can be queried from there with one of the
1531 o A few binaries are silently added to the repository, which can be used
1532 to replay kernel events from initramfs instead of using coldplug. udevd
1533 can be instructed now to queue-up events while the stored events from
1534 initramfs are filled into the udevd-queue. This code is still under
1535 development and there is no documentation now besides the code itself.
1536 The additional binaries get compiled, but are not installed by default.
1538 o There is also a temporary fix for a performance problem where too many
1539 events happen in parallel and every event needs to parse the rules.
1540 udev can now read precompiled rules stored on disk. This is likely to be
1541 replaced by a more elegant solution in a future udev version.
1545 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1546 Fix for libsysfs not to expect this file was added.
1550 All rules are applied now, but only the first matching rule with a NAME-key
1551 will be applied. All later rules with NAME-key are completely ignored. This
1552 way system supplied symlinks or permissions gets applied to user-defined
1556 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1557 to some rules, to keep the old behavior.
1559 The rules are read on "remove"-events too. That makes is possible to match
1560 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1561 instruct udev to ignore an event (OPTIONS="ignore_device").
1562 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1564 The new RUN-key supports rule-based execution of programs after device-node
1565 handling. This is meant as a general replacement for the dev.d/-directories
1566 to give fine grained control over the execution of programs.
1568 The %s{}-sysfs format char replacement values are searched at any of the
1569 devices in the device chain now, not only at the class-device.
1571 We support log priority levels now. The value udev_log in udev.conf is used
1572 to determine what is printed to syslog. This makes it possible to
1573 run a version with compiled-in debug messages in a production environment
1574 which is sometimes needed to find a bug.
1575 It is still possible to supress the inclusion of _any_ syslog usage with
1576 USE_LOG=false to create the smallest possible binaries if needed.
1577 The configured udev_log value can be overridden with the environment variable
1582 Possible use of a system-wide klibc:
1583 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1584 will link against an external klibc and our own version will be ignored.
1588 We support an unlimited count of symlinks now.
1590 If USE_STATIC=true is passed to a glibc build, we link statically and use
1591 a built-in userdb parser to resolve user and group names.
1593 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1594 we walk up the chain of physical devices to find a match.
1596 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1597 easy to skip certain attribute matches without composing rules with weird
1598 character class negations like:
1599 KERNEL="[!s][!c][!d]*"
1600 this can now be replaced with:
1602 The current simple '=' is still supported, and should work as it does today,
1603 but existing rules should be converted if possible, to be better readable.
1605 We have new ENV{}== key now, to match against a maximum of 5 environment
1608 udevstart is its own binary again, because we don't need co carry this araound
1609 with every forked event.