5 The processed udev events get send back to the netlink socket. Libudev
6 provides access to these events. This is work-in-progress, to replace
7 the DeviceKit daemon functionality directly with libudev. There are
8 upcoming kernel changes to allow non-root users to subcribe to these
15 "udevadm settle" now optionally accepts a range of events to wait for,
16 instead of waiting for "all" events.
22 The installed watch for block device metadata changes is now removed
23 during event hadling, because some (broken) tools may be called from udev
24 rules and (wrongly) open the device with write access. After the finished
25 event handling the watch is restored.
31 Device nodes can be watched for changes with inotify with OPTIONS="watch".
32 If closed after being opened for writing, a "change" uevent will occur.
33 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
39 The udevadm test command has no longer a --force option, nodes and symlinks
40 are always updated with a test run now.
42 The udevd daemon can be started with --resolve-names=never to avoid all user
43 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
44 lookup user and groups every time events are handled.
50 We are currently merging the Ubuntu rules in the udev default rules,
51 and get one step closer to provide a common Linux /dev setup, regarding
52 device names, symlinks, and default device permissions. On udev startup,
53 we now expect the following groups to be resolvable to their ids with
55 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
56 LDAP setups need to make sure, that these groups are always resolvable at
57 bootup, with only the rootfs mounted, and without network access available.
59 Some systems may need to add some new, currently not used groups, or need
60 to add some users to new groups, but the cost of this change is minimal,
61 compared to the pain the current, rather random, differences between the
62 various distributions cause for upstream projects and third-party vendors.
64 In general, "normal" users who log into a machine should never be a member
65 of any such group, but the device-access should be managed by dynamic ACLs,
66 which get added and removed for the specific users on login/logout and
67 session activity/inactivity. These groups are only provided for custom setups,
68 and mainly system services, to allow proper privilege separation.
69 A video-streaming daemon uid would be a member of "audio" and "video", to get
70 access to the sound and video devices, but no "normal" user should ever belong
71 to the "audio" group, because he could listen to the built-in microphone with
72 any ssh-session established from the other side of the world.
74 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
75 which do not depend on the kernel device name. As usual, unique
76 devices - only a single one per product connected, or a real
77 USB serial number in the device - are always found with the same
78 name in the by-id/ directory.
79 Completely identical devices may overwrite their names in by-id/
80 and can only be found reliably in the by-path/ directory. Devices
81 specified by by-path/ must not change their connection, like the
82 USB port number they are plugged in, to keep their name.
84 To support some advanced features, Linux 2.6.22 is the oldest supported
85 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
86 supported. Older kernels should still work, and devices nodes should be
87 reliably created, but some rules and libudev will not work correctly because
88 the old kernels do not provide the expected information or interfaces.
94 Fix for a possible segfault while swapping network interface names in udev
101 The group "video" is part of the default rules now.
105 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
106 block devices in some cases. No common distro uses this option anymore,
107 and we do not get enough testing for this and recent udev versions. If
108 this option is not needed to run some old distro with a new kernel,
109 it should be disabled in the kernel config.
111 Bugfix for the $links substitution variable, which may crash if no links
112 are created. This should not happen in usual setups because we always
113 create /dev/{block,char}/ links.
115 The strings of the parsed rules, which are kept in memory, no longer
116 contain duplicate entries, or duplicate tails of strings. This, and the
117 new rules parsing/matching code reduces the total in-memory size of
118 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
121 The export of DEVTYPE=disk/partition got removed from the default
122 rules. This value is available from the kernel. The pnp shell script
123 modprobe hack is removed from the default rules. ACPI devices have _proper_
124 modalias support and take care of the same functionality.
125 Installations which support old kernels, but install current default
126 udev rules may want to add that to the compat rules file.
128 Libvolume_id now always probes for all known filesystems, and does not
129 stop at the first match. Some filesystems are marked as "exclusive probe",
130 and if any other filesytem type matches at the same time, libvolume_id
131 will, by default, not return any probing result. This is intended to prevent
132 mis-detection with conflicting left-over signatures found from earlier
133 file system formats. That way, we no longer depend on the probe-order
134 in case of multiple competing signatures. In some setups the kernel allows
135 to mount a volume with just the old filesystem signature still in place.
136 This may damage the new filesystem and cause data-loss, just by mounting
137 it. Because volume_id can not decide which one the correct signature is,
138 the wrong signatures need to be removed manually from the volume, or the
139 volume needs to be reformatted, to enable filesystem detection and possible
144 Fix segfault if compiled without optimization and dbg() does not get
145 compiled out and uses variables which are not available.
149 Bugfixes. (And maybe new bugs. :))
151 The rule matching engine got converted from a rule list to a token
152 array which reduced the in-memory rules representation of a full
153 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
154 Limits like 5 ENV and ATTR matches, and one single instance for most
155 other keys per rule are gone.
157 The NAME assignment is no longer special cased. If later rules assign
158 a NAME value again, the former value will be overwritten. As usual
159 for most other keys, the NAME value can be protected by doing a final
160 assignment with NAME:="<value>".
162 All udev code now uses libudev, which is also exported. The library
163 is still under development, marked as experimental, and its interface
164 may change as long as the DeviceKit integration is not finished.
166 Many thanks to Alan Jenkins for his continuous help, and finding and
167 optimizing some of the computing expensive parts.
173 Kernel devices and device nodes are connected now by reverse indizes in
174 /sys and /dev. A device number retrieved by a stat() or similar, the
175 kernel device directory can be found by looking up:
176 /sys/dev/{block,char}/<maj>:<min>
177 and the device node of the same device by looking up:
178 /dev/{block,char}/<maj>:<min>
182 Fix recently introduced bug, which caused a compilation without large
183 file support, where vol_id does not recognize raid signatures at the end
186 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
187 Seems some kernel versions prevent the creation of the ieee-* links,
188 so people used the scsi-* link which disappeared now.
190 More libudev work. Almost all udevadm functionality comes from libudev
193 udevadm trigger has a new option --type, which allows to trigger events
194 for "devices", for "subsystems", or "failed" devices. The old option
195 --retry-failed" still works, but is no longer mentioned in the man page.
201 The udevadm info --device-id-of-file= output has changed to use
202 the obvious format. Possible current users should use the --export
203 option which is not affected.
205 The old udev commands symlinks to udevadm are not installed, if
206 these symlinks are used, a warning is printed.
212 Optical drive's media is no longer probed for raid signatures,
213 reading the end of the device causes some devices to malfunction.
214 Also the offset of the last session found is used now to probe
217 The volume_id library got a major version number update to 1,
218 some deprecated functions are removed.
220 A shared library "libudev" gets installed now to provide access
221 to udev device information. DeviceKit, the successor of HAL, will
222 need this library to access the udev database and search sysfs for
224 The library is currently in an experimental state, also the API is
225 expected to change, as long as the DeviceKit integration is not
230 We use ./configure now. See INSTALL for details. Current
233 "/usr" - prefix for man pages, include files
235 "" - the root filesystem, prefix for libs and binaries
239 "lib" - directory name for libraries, not a path name
240 multilib 64bit systems may use "lib64" instead of "lib"
242 compile-in verbose debug messages
244 disable all logging and compile-out all log strings
246 link against SELInux libraries, to set the expected context
249 In the default rules, the group "disk" gets permissions 0660 instead
250 of 0640. One small step closer to unify distro rules. Some day, all
251 distros hopefully end up with the same set of rules.
253 No symlinks to udevadm are installed anymore, if they are still needed,
254 they should be provided by the package.
260 Default udev rules, which are not supposed to be edited by the user, should
261 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
262 the udev package and will be replaced with an update. Udev will pick up rule
264 /lib/udev/rules.d/ - default installed rules
265 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
266 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
267 It does not matter in which directory a rule file lives, all files are sorted
270 To help creating /dev/root, we have now:
271 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
274 In case the current --device-id-of-file is already used, please switch to
275 the --export format version, it saves the output parsing and the old
276 format will be changed to use ':' as a separator, like the format in the
281 Fix cdrom_id to properly recognize blank media.
287 Tape drive id-data is queried from /dev/bsg/* instead of the tape
288 nodes. This avoids rewinding tapes on open().
294 The symlinks udevcontrol and udevtrigger are no longer installed by
297 The scsi_id program does not depend on sysfs anymore. It can speak
298 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
299 data, which should solve some old problems with tape devices, where
300 we better do not open all tape device nodes to identify the device.
306 The cdrom_id program is replaced by an advanced version, which can
307 detect most common device types, and also properties of the inserted
308 media. This is part of moving some basic functionality from HAL into
309 udev (and the kernel).
315 The last WAIT_FOR_SYSFS rule is removed from the default rules.
317 The symlinks to udevadm for the debugging tools: udevmonitor and
318 udevtest are no longer created.
320 The symlinks to the udevadm man page for the old tool names are
323 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
324 should be prefixed with '@' to indicate that the path is not a
335 Udevstart is removed from the tree, it did not get installed for
336 a long time now, and is long replaced by trigger and settle.
342 All udev tools are merged into a single binary called udevadm.
343 The old names of the tools are built-in commands in udevadm now.
344 Symlinks to udevadm, with the names of the old tools, provide
345 the same functionality as the standalone tools. There is also
346 only a single udevadm.8 man page left for all tools.
348 Tools like mkinitramfs should be checked, if they need to include
349 udevadm in the list of files.
359 The etc/udev/rules.d/ directory now contains a default set of basic
360 udev rules. This initial version is the result of a rules file merge
361 of Fedora and openSUSE. For these both distros only a few specific
362 rules are left in their own file, named after the distro. Rules which
363 are optionally installed, because they are only valid for a specific
364 architecture, or rules for subsystems which are not always used are
365 in etc/udev/packages/.
371 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
372 actions by dynamically created rules.
374 SYMLINK=="<value>" matches agains the entries in the list of
375 currently defined symlinks. The links are not created in the
376 filesystem at that point in time, but the values can be matched.
378 RUN{ignore_error}+="<program>" will ignore any exit code from the
379 program and not record as a failed event.
385 Final merge of patches/features from the Ubuntu package.
391 Control characters in filesystem label strings are no longer silenty
392 removed, but hex-encoded, to be able to uniquely identify the device
393 by its symlink in /dev/disk/by-label/.
394 If libvolume_id is used by mount(8), LABEL= will work as expected,
395 if slashes or other characters are used in the label string.
397 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
398 can be specified now. The TEST key accepts an optional mode mask
399 TEST{0100}=="<is executable file>".
401 Scsi_id now supports a mode without expecting scsi-specific sysfs
402 entries to allow the extraction of cciss-device persistent properties.
408 In the future, we may see uuid's which are just simple character
409 strings (see the DDF Raid Specification). For that reason vol_id now
410 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
411 the creation of symlinks, the *_SAFE values ensure, that no control
412 or whitespace characters are used in the filename.
414 Possible users of libvolume_id, please use the volume_id_get_* functions.
415 The public struct will go away in a future release of the library.
421 Removal of useless extras/eventrecorder.sh.
431 The directory multiplexer for dev.d/ and hotplug.d are finally removed
432 from the udev package.
438 Symlinks can have priorities now, the priority is assigned to the device
439 and specified with OPTIONS="link_priority=100". Devices with higher
440 priorities overwrite the symlinks of devices with lower priorities.
441 If the device that currently owns the link, goes away, the symlink
442 will be removed, and recreated, pointing to the next device with the
443 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
444 more reliable, if multiple devices contain the same metadata and overwrite
447 The dasd_id program is removed from the udev tree, and dasdinfo, with the
448 needed rules, are part of the s390-tools now.
450 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
451 we may get the scsi sysfs mess fixed some day, and this will only catch
452 the devices we are looking for.
454 USB serial numbers for storage devices have the target:lun now appended,
455 to make it possibble to distinguish broken multi-lun devices with all
456 the same SCSI identifiers.
458 Note: The extra "run_directory" which searches and executes stuff in
459 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
460 with the next release. Make sure, that you don't use it anymore, or
461 provides your own implementation of that inefficient stuff.
462 We are tired of reports about a "slow udev", because these directories
463 contain stuff, that runs with _every_ event, instead of using rules,
464 that run programs only for the matching events.
474 DRIVER== will match only for devices that actually have a real
475 driver. DRIVERS== must be used, if parent devices should be
476 included in the match.
478 Libvolume_id's "linux_raid" detection needed another fix.
486 Add additional check to volume_id detection of via_raid, cause
487 some company decided to put a matching pattern all over the empty
488 storage area of their music players.
492 Fix path_id for SAS devices.
496 The udev daemon can be started with --debug-trace now, which will
497 execute all events serialized to get a chance to catch a possible
498 action that crashes the box.
500 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
501 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
502 are excluded from the warning. Referencing parent attributes directly
503 may break when something in the kernel driver model changes. Udev will
504 just find the attribute by walking up the parent chain.
506 Udevtrigger now sorts the list of devices depending on the device
507 dependency, so a "usb" device is triggered after the parent "pci"
512 Revert persistent-storage ata-serial '_' '-' replacement.
518 Udevtrigger can now filter the list of devices to be triggered. Matches
519 for subsystems or sysfs attributes can be specified.
521 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
522 zero-sized files to avoid pointing to /sys and confuse broken tools which
523 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
526 The rules and scripts to create udev rules for persistent network
527 devices and optical drives are in the extras/rules_generator directory
528 now. If you use something similar, please consider replacing your own
529 version with this, to share the support effort. The rule_generator
530 installs its own rules into /etc/udev/rules.d.
532 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
533 the rule_generator depends on cdrom_id to be called in an earlier rule.
539 Renaming of some key names (the old names still work):
540 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
541 (The behavior of the key DRIVER will change soon in one of the next
542 releases, to match only the event device, please switch to DRIVERS
543 instead. If DRIVER is used, it will behave like DRIVERS, but an error
545 With the new key names, we have a more consistent and simpler scheme.
546 We can match the properties of the event device only, with: KERNEL,
547 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
548 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
549 longer mentioned in the man page and should be switched in the rule
552 ATTR{file}="value" can be used now, to write to a sysfs file of the
553 event device. Instead of:
554 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
556 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
558 All the PHYSDEV* keys are deprecated and will be removed from a
560 PHYDEVPATH - is the path of a parent device and should not be
562 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
563 matched with SUBSYSTEMS==
564 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
565 Newer kernels will have DRIVER in the environment,
566 for older kernels udev puts in. Class device will
567 no longer carry this property of a parent and
568 DRIVERS== can be used to match such a parent value.
569 Note that ENV{DRIVER} is only available for a few bus devices, where
570 the driver is already bound at device event time. On coldplug, the
571 events for a lot devices are already bound to a driver, and they will have
572 that value set. But on hotplug, at the time the kernel creates the device,
573 it can't know what driver may claim the device after that, therefore
574 in most cases it will be empty.
576 Failed events should now be re-triggered with:
577 udevtrigger --retry-failed.
578 Please switch to this command, so we keep the details of the /dev/.udev/failed/
579 files private to the udev tools. We may need to switch the current symlink
580 target, cause some obviously broken tools try to scan all files in /dev
581 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
582 million times. This takes ages on slow boxes.
584 The udevinfo attribute walk (-a) now works with giving a device node
585 name (-n) instead of a devpath (-p). The query now always works, also when
586 no database file was created by udev.
588 The built-in /etc/passwd /etc/group parser is removed, we always depend on
589 getpwnam() and getgrnam() now. One of the next releases will depend on
590 fnmatch() and may use getopt_long().
594 Bugfixes and small improvements.
598 Fix path_id for recent kernels.
604 Added support for swapping network interface names, by temporarily
605 renaming the device and wait for the target name to become free.
609 The built-in MODALIAS key and substitution is removed.
613 The binary firmware helper is replaced by the usual simple
614 shell script. Udevsend is removed from the tree.
622 Some more keys require the correct use of '==' and '=' depending
623 on the kind of operation beeing an assignment or a match. Rules
624 with invalid operations are skipped and logged to syslog. Please
625 test with udevtest if the parsing of your rules throws errors and
626 fix possibly broken rules.
630 Provide "udevsettle" to wait for all current udev events to finish.
631 It also watches the current kernel netlink queue by comparing the
632 even sequence number to make sure that there are no current pending
633 events that have not already arrived in the daemon.
637 Fix rule to skip persistent rules for removable IDE devices, which
638 also skipped optical IDE drives.
640 All *_id program are installed in /lib/udev/ by default now.
642 No binary is stripped anymore as this should be done in the
643 packaging process and not at build time.
645 libvolume_id is provided as a shared library now and vol_id is
646 linked against it. Also one of the next HAL versions will require
647 this library, and the HAL build process will also require the
648 header file to be installed. The copy of the same code in HAL will
649 be removed to have only a single copy left on the system.
653 Add persistent links for SCSI tapes. The rules file is renamed
654 to 60-persistent-storage.rules.
656 Create persistent path for usb devices. Can be used for all sorts
657 of devices that can't be distinguished by other properties like
658 multiple identical keyboards and mice connected to the same box.
660 Provide "udevtrigger" program to request events on coldplug. The
661 shell script is much too slow with thousends of devices.
665 Fix persistent disk rules to exclude removable IDE drives.
667 Warn if %e, $modalias or MODALIAS is used.
671 Fix queue export, which wasn't correct for subsequent add/remove
672 events for the same device.
676 Fix cramfs detection on big endian.
678 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
683 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
684 attributes were only checked at the parent device that matched the
685 by BUS requested subsystem. Fix it to also look at the device we
686 received the event for.
688 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
693 Fix a bug where NAME="" would prevent RUN from beeing executed.
695 RUN="/bin/program" does not longer automatically add the subsystem
696 as the first parameter. This is from the days of /sbin/hotplug
697 which is dead now and it's just confusing to need to add a space at
698 the end of the program name to prevent this.
699 If you use rules that need the subsystem as the first parameter,
700 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
701 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
705 The udev man page has moved to udev(7) as it does not describe a command
706 anymore. The programs udev, udevstart and udevsend are no longer installed
707 by default and must be copied manually, if they should be installed or
708 included in a package.
710 Fix a bug where "ignore_device" could run earlier collected RUN keys before
711 the ignore rule was applied.
713 More preparation for future sysfs changes. usb_id and scsi_id no longer
714 depend on a magic order of devices in the /devices chain. Specific devices
715 should be requested by their subsytem.
717 This will always find the scsi parent device without depending on a specific
719 dev = sysfs_device_get(devpath);
720 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
722 The "device" link in the current sysfs layout will be automatically
723 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
724 parent in the devpath. If a device is requested by it's symlink, like all
725 class devices in the new sysfs layout will look like, it gets automatically
726 resolved and substituted with the real devpath and not the symlink path.
729 A similar logic must be applied to _all_ sysfs users, including
730 scripts, that search along parent devices in sysfs. The explicit use of
731 the "device" link must be avoided. With the future sysfs layout all
732 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
733 back to the "class" or the "bus". The layout of the parent devices in
734 /devices is not necessarily expected to be stable across kernel releases and
735 searching for parents by their subsystem should make sysfs users tolerant
736 for changed parent chains.
740 Prepare udev to work with the experimental kernel patch, that moves
741 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
743 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
744 moving the class devices to /sys/devices.
746 Thanks again to Marco for help finding a hopefully nice compromise
747 to make %b simpler and working again.
751 Complete removal of libsysfs, replaced by simple helper functions
752 which are much simpler and a bit faster. The udev daemon operatesentirely
753 on event parameters and does not use sysfs for simple rules anymore.
754 Please report any new bugs/problems, that may be caused by this big
755 change. They will be fixed immediately.
757 The enumeration format character '%e' is deprecated and will be
758 removed sometimes from a future udev version. It never worked correctly
759 outside of udevstart, so we can't use it with the new parallel
760 coldplug. A simple enumeration is as useless as the devfs naming
761 scheme, just get rid of both if you still use it.
763 MODALIAS and $modalias is not needed and will be removed from one of
764 the next udev versions, replace it in all rules with ENV{MODALIAS} or
765 the sysfs "modalias" value.
767 Thanks a lot to Marco for all his help on finding and fixing bugs.
771 Let scsi_id request libata drive serial numbers from page 0x80.
773 Renamed etc/udev/persistent.rules to persistent-disk.rules and
774 added /dev/disk/by-name/* for device mapper device names.
776 Removed %e from the man page. It never worked reliably outside
777 of udevstart and udevstart is no longer recommended to use.
781 Symlinks are now exported to the event environment. Hopefully it's no
782 longer needed to run udevinfo from an event process, like it was
783 mentioned on the hotplug list:
784 UDEV [1134776873.702967] add@/block/sdb
787 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
791 Fix a problem if udevsend is used as the hotplug handler and tries to use
792 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
793 and this kind of problems will hopefully go away soon.
797 All built-in logic to work around bad sysfs timing is removed with this
798 version. The need to wait for sysfs files is almost fixed with a kernel
799 version that doesn't work with this udev version anyway. Until we fix
800 the timing of the "bus" link creation, the former integrated logic should
801 be emulated by a rule placed before all other rules:
802 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
804 The option "udev_db" does no longer exist. All udev state will be in
805 /$udev_root/.udev/ now, there is no longer an option to set this
807 If the init script or something else used this value, just depend on
808 this hardcoded path. But remember _all_content_ of this directory is
809 still private to udev and can change at any time.
811 Default location for rule sripts and helper programs is now: /lib/udev/.
812 Everything that is not useful on the commandline should go into this
813 directory. Some of the helpers in the extras folder are installed there
814 now. The rules need to be changed, to find the helpers there.
816 Also /lib/udev/devices is recommended as a directory where packages or
817 the user can place real device nodes, which get copied over to /dev at
818 every boot. This should replace the various solutions with custom config
821 Udevsend does no longer start the udev daemon. This must be done with
822 the init script that prepares /dev on tmpfs and creates the initial nodes,
823 before starting the daemon.
827 Silent a too verbose error logging for the old hotplug.d/ dev.d/
830 The copy of klibc is removed. A systemwide installed version of klibc
831 should be used to build a klibc udev now.
835 NAME="" will not create any nodes, but execute RUN keys. To completely
836 ignore an event the OPTION "ignore_device" should be used.
838 After removal of the reorder queue, events with a TIMEOUT can be executed
839 without any queuing now.
843 Fixed bug in udevd, if inotify is not available. We depend on netlink
844 uevents now, kernels without that event source will not work with that
845 version of udev anymore.
849 The rule parsing happens now in the daemon once at startup, all udev
850 event processes inherit the already parsed rules from the daemon.
851 It is shipped with SUSE10.0 and reduces heavily the system load at
852 startup. The option to save precompiled rules and let the udev process
853 pick the them up is removed, as it's no longer needed.
855 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
856 device. Libsysfs is changed to "translate" the requested link into the
857 real device path, as it would happen with the hotplug event. Otherwise
858 device removal and the udev database will not work.
860 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
863 A few improvements for vol_id, the filesytem probing code.
867 Fix a stupid typo in extras/run_directory for "make install".
869 scsi_id creates the temporary devnode now in /dev for usage with a
870 non-writable /tmp directory.
872 The uevent kernel socket buffer can carry app. 50.000 events now,
873 let's see who can break this again. :)
875 The upcoming kernel will have a new input driver core integration.
876 Some class devices are now symlinks to the real device. libsysfs
877 needs a fix for this to work correctly. Udevstart of older udev
878 versions will _not_ create these devices!
882 Fix a 'install' target in the Makefile, that prevents EXTRAS from
887 A bunch of mostly trivial bugfixes. From now on no node name or
888 symlink name can contain any character than plain whitelisted ascii
889 characters or validated utf8 byte-streams. This is needed for the
890 /dev/disk/by-label/* links, because we import untrusted data and
891 export it to the filesystem.
895 More bugfixes. If udevd was started from the kernel, we don't
896 have stdin/stdout/stderr, which broke the forked tools in some
901 Bugfix. udevstart event ordering was broken for a long time.
902 The new run_program() uncovered it, because /dev/null was not
903 available while we try to run external programs.
904 Now udevstart should create it before we run anything.
908 Minor bugfixes and some distro rules updates. If you don't have the
909 persistent disk rules in /dev/disk/by-*/* on your distro, just
910 grab it from here. :)
914 We can use socket communication now to pass events from udev to
916 RUN+="socket:/org/freedesktop/hal/udev_event"
917 will pass the whole udev event to the HAL daemon without the need
918 for a forked helper. (See ChangeLog for udevmonitor, as an example)
922 Mostly bugfixes and see ChangeLog.
924 The test for the existence of an environment value should be
926 ENV{KEY}=="*" to ENV{KEY}=="?*"
927 because "*" will not fail anymore, if the key does not exist or
932 Bugfixes and a few tweaks described in the ChangeLog.
936 Mostly a Bugfix release.
938 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
939 timing with custom rules.
943 We changed the internal rule storage format. Our large rule files took
944 2 MB of RAM, with the change we are down to 99kB.
946 If the device-node has been created with default name and no symlink or
947 options are to remenber, it is not longer stored in the udevdb. HAL will
948 need to be updated to work correctly with that change.
950 To overrride optimization flags, OPTFLAGS may be used now.
958 Major changes happened with this release. The goal is to take over the
959 complete kernel-event handling and provide a more efficient way to dispatch
960 kernel events. Replacing most of the current shell script logic and the
961 kernel forked helper with a netlink-daemon and a rule-based event handling.
963 o udevd listens to netlink events now. The first valid netlink event
964 will make udevd ignore any message from udevsend that contains a
965 SEQNUM, to avoid duplicate events. The forked events can be disabled
967 echo "" > /proc/sys/kernel/hotplug
968 For full support, the broken input-subsytem needs to be fixed, not to
969 bypass the driver core.
971 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
972 removed from udev itself and must be emulated by calling small
973 helper binaries provided in the extras folder:
974 make EXTRAS=extras/run_directory/
975 will build udev_run_devd and udev_run_hotplugd, which can be called
976 from a rule if needed:
977 RUN+="/sbin/udev_run_hotplugd"
978 The recommended way to handle this is to convert all the calls from
979 the directories to explicit udev rules and get completely rid of the
980 multiplexing. (To catch a ttyUSB event, you now no longer need to
981 fork and exit 300 tty script instances you are not interested in, it
982 is just one rule that matches exactly the device.)
984 o udev handles now _all_ events not just events for class and block
985 devices, this way it is possible to control the complete event
986 behavior with udev rules. Especially useful for rules like:
987 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
989 o As used in the modalias rule, udev supports now textual
990 substitution placeholder along with the usual format chars. This
991 needs to be documented, for now it's only visible in udev_rules_parse.c.
993 o The rule keys support now more operations. This is documented in the
994 man page. It is possible to add values to list-keys like the SYMLINK
995 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
996 Also "final"-assignments are supported by using KEY:="value", which will
997 prevent changing the key by any later rule.
999 o kernel 2.6.12 has the "detached_state" attribute removed from
1000 sysfs, which was used to recognize sysfs population. We switched that
1001 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1002 Running this udev version on older kernels may cause a short delay for
1005 o To provide infrastructure for persistent device naming, the id programs:
1006 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1007 to export the probed data in environment key format:
1008 pim:~ # /sbin/ata_id --export /dev/hda
1009 ID_MODEL=HTS726060M9AT00
1010 ID_SERIAL=MRH401M4G6UM9B
1011 ID_REVISION=MH4OA6BA
1013 The following rules:
1014 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1015 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1018 kay@pim:~> tree /dev/disk
1021 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1022 | `-- IBM-Memory_Key -> ../../sda
1024 | |-- swap -> ../../hda1
1025 | |-- date -> ../../sda1
1026 | `-- home -> ../../hda3
1028 |-- 2E08712B0870F2E7 -> ../../hda3
1029 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1030 |-- E845-7A89 -> ../../sda1
1031 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1033 The IMPORT= operation will import these keys in the environment and make
1034 it available for later PROGRAM= and RUN= executed programs. The keys are
1035 also stored in the udevdb and can be queried from there with one of the
1038 o A few binaries are silently added to the repository, which can be used
1039 to replay kernel events from initramfs instead of using coldplug. udevd
1040 can be instructed now to queue-up events while the stored events from
1041 initramfs are filled into the udevd-queue. This code is still under
1042 development and there is no documentation now besides the code itself.
1043 The additional binaries get compiled, but are not installed by default.
1045 o There is also a temporary fix for a performance problem where too many
1046 events happen in parallel and every event needs to parse the rules.
1047 udev can now read precompiled rules stored on disk. This is likely to be
1048 replaced by a more elegant solution in a future udev version.
1052 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1053 Fix for libsysfs not to expect this file was added.
1057 All rules are applied now, but only the first matching rule with a NAME-key
1058 will be applied. All later rules with NAME-key are completely ignored. This
1059 way system supplied symlinks or permissions gets applied to user-defined
1063 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1064 to some rules, to keep the old behavior.
1066 The rules are read on "remove"-events too. That makes is possible to match
1067 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1068 instruct udev to ignore an event (OPTIONS="ignore_device").
1069 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1071 The new RUN-key supports rule-based execution of programs after device-node
1072 handling. This is meant as a general replacement for the dev.d/-directories
1073 to give fine grained control over the execution of programs.
1075 The %s{}-sysfs format char replacement values are searched at any of the
1076 devices in the device chain now, not only at the class-device.
1078 We support log priority levels now. The value udev_log in udev.conf is used
1079 to determine what is printed to syslog. This makes it possible to
1080 run a version with compiled-in debug messages in a production environment
1081 which is sometimes needed to find a bug.
1082 It is still possible to supress the inclusion of _any_ syslog usage with
1083 USE_LOG=false to create the smallest possible binaries if needed.
1084 The configured udev_log value can be overridden with the environment variable
1089 Possible use of a system-wide klibc:
1090 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1091 will link against an external klibc and our own version will be ignored.
1095 We support an unlimited count of symlinks now.
1097 If USE_STATIC=true is passed to a glibc build, we link statically and use
1098 a built-in userdb parser to resolve user and group names.
1100 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1101 we walk up the chain of physical devices to find a match.
1103 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1104 easy to skip certain attribute matches without composing rules with weird
1105 character class negations like:
1106 KERNEL="[!s][!c][!d]*"
1107 this can now be replaced with:
1109 The current simple '=' is still supported, and should work as it does today,
1110 but existing rules should be converted if possible, to be better readable.
1112 We have new ENV{}== key now, to match against a maximum of 5 environment
1115 udevstart is its own binary again, because we don't need co carry this araound
1116 with every forked event.