5 The udev daemon will now create /dev/null, /dev/console, /dev/kmsg at
6 startup, if they don't exist already.
8 Libudev allows to subscribe to udev events. To prevent unwanted messages
9 to be delivered, and waking up the subscribing process, a filter can be
10 installed, to drop messages inside a kernel socket filter. The filters
11 match on the <subsytem>:<devtype> properties of the device.
12 This is part of the ongoing effort to replace HAL, and switch current
13 users over to directly use libudev, or for higher-level services use the
14 specialized D-Bus interface of a DeviceKit service.
15 Libudev is still marked as experimental, and its interface might
16 change if needed, but no major changes of the currently exported interface
17 are expected anymore, and a first stable release should happen soon.
19 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
20 is not supported since while and udevd will log an error message at
23 DVB device naming is supplied by the kernel now. In case older kernels
24 need to be supported, the old shell script should be added to a compat
31 The processed udev events get send back to the netlink socket. Libudev
32 provides access to these events. This is work-in-progress, to replace
33 the DeviceKit daemon functionality directly with libudev. There are
34 upcoming kernel changes to allow non-root users to subcribe to these
41 "udevadm settle" now optionally accepts a range of events to wait for,
42 instead of waiting for "all" events.
48 The installed watch for block device metadata changes is now removed
49 during event hadling, because some (broken) tools may be called from udev
50 rules and (wrongly) open the device with write access. After the finished
51 event handling the watch is restored.
57 Device nodes can be watched for changes with inotify with OPTIONS="watch".
58 If closed after being opened for writing, a "change" uevent will occur.
59 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
65 The udevadm test command has no longer a --force option, nodes and symlinks
66 are always updated with a test run now.
68 The udevd daemon can be started with --resolve-names=never to avoid all user
69 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
70 lookup user and groups every time events are handled.
76 We are currently merging the Ubuntu rules in the udev default rules,
77 and get one step closer to provide a common Linux /dev setup, regarding
78 device names, symlinks, and default device permissions. On udev startup,
79 we now expect the following groups to be resolvable to their ids with
81 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
82 LDAP setups need to make sure, that these groups are always resolvable at
83 bootup, with only the rootfs mounted, and without network access available.
85 Some systems may need to add some new, currently not used groups, or need
86 to add some users to new groups, but the cost of this change is minimal,
87 compared to the pain the current, rather random, differences between the
88 various distributions cause for upstream projects and third-party vendors.
90 In general, "normal" users who log into a machine should never be a member
91 of any such group, but the device-access should be managed by dynamic ACLs,
92 which get added and removed for the specific users on login/logout and
93 session activity/inactivity. These groups are only provided for custom setups,
94 and mainly system services, to allow proper privilege separation.
95 A video-streaming daemon uid would be a member of "audio" and "video", to get
96 access to the sound and video devices, but no "normal" user should ever belong
97 to the "audio" group, because he could listen to the built-in microphone with
98 any ssh-session established from the other side of the world.
100 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
101 which do not depend on the kernel device name. As usual, unique
102 devices - only a single one per product connected, or a real
103 USB serial number in the device - are always found with the same
104 name in the by-id/ directory.
105 Completely identical devices may overwrite their names in by-id/
106 and can only be found reliably in the by-path/ directory. Devices
107 specified by by-path/ must not change their connection, like the
108 USB port number they are plugged in, to keep their name.
110 To support some advanced features, Linux 2.6.22 is the oldest supported
111 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
112 supported. Older kernels should still work, and devices nodes should be
113 reliably created, but some rules and libudev will not work correctly because
114 the old kernels do not provide the expected information or interfaces.
120 Fix for a possible segfault while swapping network interface names in udev
127 The group "video" is part of the default rules now.
131 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
132 block devices in some cases. No common distro uses this option anymore,
133 and we do not get enough testing for this and recent udev versions. If
134 this option is not needed to run some old distro with a new kernel,
135 it should be disabled in the kernel config.
137 Bugfix for the $links substitution variable, which may crash if no links
138 are created. This should not happen in usual setups because we always
139 create /dev/{block,char}/ links.
141 The strings of the parsed rules, which are kept in memory, no longer
142 contain duplicate entries, or duplicate tails of strings. This, and the
143 new rules parsing/matching code reduces the total in-memory size of
144 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
147 The export of DEVTYPE=disk/partition got removed from the default
148 rules. This value is available from the kernel. The pnp shell script
149 modprobe hack is removed from the default rules. ACPI devices have _proper_
150 modalias support and take care of the same functionality.
151 Installations which support old kernels, but install current default
152 udev rules may want to add that to the compat rules file.
154 Libvolume_id now always probes for all known filesystems, and does not
155 stop at the first match. Some filesystems are marked as "exclusive probe",
156 and if any other filesytem type matches at the same time, libvolume_id
157 will, by default, not return any probing result. This is intended to prevent
158 mis-detection with conflicting left-over signatures found from earlier
159 file system formats. That way, we no longer depend on the probe-order
160 in case of multiple competing signatures. In some setups the kernel allows
161 to mount a volume with just the old filesystem signature still in place.
162 This may damage the new filesystem and cause data-loss, just by mounting
163 it. Because volume_id can not decide which one the correct signature is,
164 the wrong signatures need to be removed manually from the volume, or the
165 volume needs to be reformatted, to enable filesystem detection and possible
170 Fix segfault if compiled without optimization and dbg() does not get
171 compiled out and uses variables which are not available.
175 Bugfixes. (And maybe new bugs. :))
177 The rule matching engine got converted from a rule list to a token
178 array which reduced the in-memory rules representation of a full
179 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
180 Limits like 5 ENV and ATTR matches, and one single instance for most
181 other keys per rule are gone.
183 The NAME assignment is no longer special cased. If later rules assign
184 a NAME value again, the former value will be overwritten. As usual
185 for most other keys, the NAME value can be protected by doing a final
186 assignment with NAME:="<value>".
188 All udev code now uses libudev, which is also exported. The library
189 is still under development, marked as experimental, and its interface
190 may change as long as the DeviceKit integration is not finished.
192 Many thanks to Alan Jenkins for his continuous help, and finding and
193 optimizing some of the computing expensive parts.
199 Kernel devices and device nodes are connected now by reverse indizes in
200 /sys and /dev. A device number retrieved by a stat() or similar, the
201 kernel device directory can be found by looking up:
202 /sys/dev/{block,char}/<maj>:<min>
203 and the device node of the same device by looking up:
204 /dev/{block,char}/<maj>:<min>
208 Fix recently introduced bug, which caused a compilation without large
209 file support, where vol_id does not recognize raid signatures at the end
212 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
213 Seems some kernel versions prevent the creation of the ieee-* links,
214 so people used the scsi-* link which disappeared now.
216 More libudev work. Almost all udevadm functionality comes from libudev
219 udevadm trigger has a new option --type, which allows to trigger events
220 for "devices", for "subsystems", or "failed" devices. The old option
221 --retry-failed" still works, but is no longer mentioned in the man page.
227 The udevadm info --device-id-of-file= output has changed to use
228 the obvious format. Possible current users should use the --export
229 option which is not affected.
231 The old udev commands symlinks to udevadm are not installed, if
232 these symlinks are used, a warning is printed.
238 Optical drive's media is no longer probed for raid signatures,
239 reading the end of the device causes some devices to malfunction.
240 Also the offset of the last session found is used now to probe
243 The volume_id library got a major version number update to 1,
244 some deprecated functions are removed.
246 A shared library "libudev" gets installed now to provide access
247 to udev device information. DeviceKit, the successor of HAL, will
248 need this library to access the udev database and search sysfs for
250 The library is currently in an experimental state, also the API is
251 expected to change, as long as the DeviceKit integration is not
256 We use ./configure now. See INSTALL for details. Current
259 "/usr" - prefix for man pages, include files
261 "" - the root filesystem, prefix for libs and binaries
265 "lib" - directory name for libraries, not a path name
266 multilib 64bit systems may use "lib64" instead of "lib"
268 compile-in verbose debug messages
270 disable all logging and compile-out all log strings
272 link against SELInux libraries, to set the expected context
275 In the default rules, the group "disk" gets permissions 0660 instead
276 of 0640. One small step closer to unify distro rules. Some day, all
277 distros hopefully end up with the same set of rules.
279 No symlinks to udevadm are installed anymore, if they are still needed,
280 they should be provided by the package.
286 Default udev rules, which are not supposed to be edited by the user, should
287 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
288 the udev package and will be replaced with an update. Udev will pick up rule
290 /lib/udev/rules.d/ - default installed rules
291 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
292 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
293 It does not matter in which directory a rule file lives, all files are sorted
296 To help creating /dev/root, we have now:
297 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
300 In case the current --device-id-of-file is already used, please switch to
301 the --export format version, it saves the output parsing and the old
302 format will be changed to use ':' as a separator, like the format in the
307 Fix cdrom_id to properly recognize blank media.
313 Tape drive id-data is queried from /dev/bsg/* instead of the tape
314 nodes. This avoids rewinding tapes on open().
320 The symlinks udevcontrol and udevtrigger are no longer installed by
323 The scsi_id program does not depend on sysfs anymore. It can speak
324 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
325 data, which should solve some old problems with tape devices, where
326 we better do not open all tape device nodes to identify the device.
332 The cdrom_id program is replaced by an advanced version, which can
333 detect most common device types, and also properties of the inserted
334 media. This is part of moving some basic functionality from HAL into
335 udev (and the kernel).
341 The last WAIT_FOR_SYSFS rule is removed from the default rules.
343 The symlinks to udevadm for the debugging tools: udevmonitor and
344 udevtest are no longer created.
346 The symlinks to the udevadm man page for the old tool names are
349 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
350 should be prefixed with '@' to indicate that the path is not a
361 Udevstart is removed from the tree, it did not get installed for
362 a long time now, and is long replaced by trigger and settle.
368 All udev tools are merged into a single binary called udevadm.
369 The old names of the tools are built-in commands in udevadm now.
370 Symlinks to udevadm, with the names of the old tools, provide
371 the same functionality as the standalone tools. There is also
372 only a single udevadm.8 man page left for all tools.
374 Tools like mkinitramfs should be checked, if they need to include
375 udevadm in the list of files.
385 The etc/udev/rules.d/ directory now contains a default set of basic
386 udev rules. This initial version is the result of a rules file merge
387 of Fedora and openSUSE. For these both distros only a few specific
388 rules are left in their own file, named after the distro. Rules which
389 are optionally installed, because they are only valid for a specific
390 architecture, or rules for subsystems which are not always used are
391 in etc/udev/packages/.
397 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
398 actions by dynamically created rules.
400 SYMLINK=="<value>" matches agains the entries in the list of
401 currently defined symlinks. The links are not created in the
402 filesystem at that point in time, but the values can be matched.
404 RUN{ignore_error}+="<program>" will ignore any exit code from the
405 program and not record as a failed event.
411 Final merge of patches/features from the Ubuntu package.
417 Control characters in filesystem label strings are no longer silenty
418 removed, but hex-encoded, to be able to uniquely identify the device
419 by its symlink in /dev/disk/by-label/.
420 If libvolume_id is used by mount(8), LABEL= will work as expected,
421 if slashes or other characters are used in the label string.
423 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
424 can be specified now. The TEST key accepts an optional mode mask
425 TEST{0100}=="<is executable file>".
427 Scsi_id now supports a mode without expecting scsi-specific sysfs
428 entries to allow the extraction of cciss-device persistent properties.
434 In the future, we may see uuid's which are just simple character
435 strings (see the DDF Raid Specification). For that reason vol_id now
436 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
437 the creation of symlinks, the *_SAFE values ensure, that no control
438 or whitespace characters are used in the filename.
440 Possible users of libvolume_id, please use the volume_id_get_* functions.
441 The public struct will go away in a future release of the library.
447 Removal of useless extras/eventrecorder.sh.
457 The directory multiplexer for dev.d/ and hotplug.d are finally removed
458 from the udev package.
464 Symlinks can have priorities now, the priority is assigned to the device
465 and specified with OPTIONS="link_priority=100". Devices with higher
466 priorities overwrite the symlinks of devices with lower priorities.
467 If the device that currently owns the link, goes away, the symlink
468 will be removed, and recreated, pointing to the next device with the
469 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
470 more reliable, if multiple devices contain the same metadata and overwrite
473 The dasd_id program is removed from the udev tree, and dasdinfo, with the
474 needed rules, are part of the s390-tools now.
476 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
477 we may get the scsi sysfs mess fixed some day, and this will only catch
478 the devices we are looking for.
480 USB serial numbers for storage devices have the target:lun now appended,
481 to make it possibble to distinguish broken multi-lun devices with all
482 the same SCSI identifiers.
484 Note: The extra "run_directory" which searches and executes stuff in
485 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
486 with the next release. Make sure, that you don't use it anymore, or
487 provides your own implementation of that inefficient stuff.
488 We are tired of reports about a "slow udev", because these directories
489 contain stuff, that runs with _every_ event, instead of using rules,
490 that run programs only for the matching events.
500 DRIVER== will match only for devices that actually have a real
501 driver. DRIVERS== must be used, if parent devices should be
502 included in the match.
504 Libvolume_id's "linux_raid" detection needed another fix.
512 Add additional check to volume_id detection of via_raid, cause
513 some company decided to put a matching pattern all over the empty
514 storage area of their music players.
518 Fix path_id for SAS devices.
522 The udev daemon can be started with --debug-trace now, which will
523 execute all events serialized to get a chance to catch a possible
524 action that crashes the box.
526 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
527 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
528 are excluded from the warning. Referencing parent attributes directly
529 may break when something in the kernel driver model changes. Udev will
530 just find the attribute by walking up the parent chain.
532 Udevtrigger now sorts the list of devices depending on the device
533 dependency, so a "usb" device is triggered after the parent "pci"
538 Revert persistent-storage ata-serial '_' '-' replacement.
544 Udevtrigger can now filter the list of devices to be triggered. Matches
545 for subsystems or sysfs attributes can be specified.
547 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
548 zero-sized files to avoid pointing to /sys and confuse broken tools which
549 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
552 The rules and scripts to create udev rules for persistent network
553 devices and optical drives are in the extras/rules_generator directory
554 now. If you use something similar, please consider replacing your own
555 version with this, to share the support effort. The rule_generator
556 installs its own rules into /etc/udev/rules.d.
558 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
559 the rule_generator depends on cdrom_id to be called in an earlier rule.
565 Renaming of some key names (the old names still work):
566 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
567 (The behavior of the key DRIVER will change soon in one of the next
568 releases, to match only the event device, please switch to DRIVERS
569 instead. If DRIVER is used, it will behave like DRIVERS, but an error
571 With the new key names, we have a more consistent and simpler scheme.
572 We can match the properties of the event device only, with: KERNEL,
573 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
574 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
575 longer mentioned in the man page and should be switched in the rule
578 ATTR{file}="value" can be used now, to write to a sysfs file of the
579 event device. Instead of:
580 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
582 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
584 All the PHYSDEV* keys are deprecated and will be removed from a
586 PHYDEVPATH - is the path of a parent device and should not be
588 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
589 matched with SUBSYSTEMS==
590 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
591 Newer kernels will have DRIVER in the environment,
592 for older kernels udev puts in. Class device will
593 no longer carry this property of a parent and
594 DRIVERS== can be used to match such a parent value.
595 Note that ENV{DRIVER} is only available for a few bus devices, where
596 the driver is already bound at device event time. On coldplug, the
597 events for a lot devices are already bound to a driver, and they will have
598 that value set. But on hotplug, at the time the kernel creates the device,
599 it can't know what driver may claim the device after that, therefore
600 in most cases it will be empty.
602 Failed events should now be re-triggered with:
603 udevtrigger --retry-failed.
604 Please switch to this command, so we keep the details of the /dev/.udev/failed/
605 files private to the udev tools. We may need to switch the current symlink
606 target, cause some obviously broken tools try to scan all files in /dev
607 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
608 million times. This takes ages on slow boxes.
610 The udevinfo attribute walk (-a) now works with giving a device node
611 name (-n) instead of a devpath (-p). The query now always works, also when
612 no database file was created by udev.
614 The built-in /etc/passwd /etc/group parser is removed, we always depend on
615 getpwnam() and getgrnam() now. One of the next releases will depend on
616 fnmatch() and may use getopt_long().
620 Bugfixes and small improvements.
624 Fix path_id for recent kernels.
630 Added support for swapping network interface names, by temporarily
631 renaming the device and wait for the target name to become free.
635 The built-in MODALIAS key and substitution is removed.
639 The binary firmware helper is replaced by the usual simple
640 shell script. Udevsend is removed from the tree.
648 Some more keys require the correct use of '==' and '=' depending
649 on the kind of operation beeing an assignment or a match. Rules
650 with invalid operations are skipped and logged to syslog. Please
651 test with udevtest if the parsing of your rules throws errors and
652 fix possibly broken rules.
656 Provide "udevsettle" to wait for all current udev events to finish.
657 It also watches the current kernel netlink queue by comparing the
658 even sequence number to make sure that there are no current pending
659 events that have not already arrived in the daemon.
663 Fix rule to skip persistent rules for removable IDE devices, which
664 also skipped optical IDE drives.
666 All *_id program are installed in /lib/udev/ by default now.
668 No binary is stripped anymore as this should be done in the
669 packaging process and not at build time.
671 libvolume_id is provided as a shared library now and vol_id is
672 linked against it. Also one of the next HAL versions will require
673 this library, and the HAL build process will also require the
674 header file to be installed. The copy of the same code in HAL will
675 be removed to have only a single copy left on the system.
679 Add persistent links for SCSI tapes. The rules file is renamed
680 to 60-persistent-storage.rules.
682 Create persistent path for usb devices. Can be used for all sorts
683 of devices that can't be distinguished by other properties like
684 multiple identical keyboards and mice connected to the same box.
686 Provide "udevtrigger" program to request events on coldplug. The
687 shell script is much too slow with thousends of devices.
691 Fix persistent disk rules to exclude removable IDE drives.
693 Warn if %e, $modalias or MODALIAS is used.
697 Fix queue export, which wasn't correct for subsequent add/remove
698 events for the same device.
702 Fix cramfs detection on big endian.
704 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
709 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
710 attributes were only checked at the parent device that matched the
711 by BUS requested subsystem. Fix it to also look at the device we
712 received the event for.
714 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
719 Fix a bug where NAME="" would prevent RUN from beeing executed.
721 RUN="/bin/program" does not longer automatically add the subsystem
722 as the first parameter. This is from the days of /sbin/hotplug
723 which is dead now and it's just confusing to need to add a space at
724 the end of the program name to prevent this.
725 If you use rules that need the subsystem as the first parameter,
726 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
727 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
731 The udev man page has moved to udev(7) as it does not describe a command
732 anymore. The programs udev, udevstart and udevsend are no longer installed
733 by default and must be copied manually, if they should be installed or
734 included in a package.
736 Fix a bug where "ignore_device" could run earlier collected RUN keys before
737 the ignore rule was applied.
739 More preparation for future sysfs changes. usb_id and scsi_id no longer
740 depend on a magic order of devices in the /devices chain. Specific devices
741 should be requested by their subsytem.
743 This will always find the scsi parent device without depending on a specific
745 dev = sysfs_device_get(devpath);
746 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
748 The "device" link in the current sysfs layout will be automatically
749 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
750 parent in the devpath. If a device is requested by it's symlink, like all
751 class devices in the new sysfs layout will look like, it gets automatically
752 resolved and substituted with the real devpath and not the symlink path.
755 A similar logic must be applied to _all_ sysfs users, including
756 scripts, that search along parent devices in sysfs. The explicit use of
757 the "device" link must be avoided. With the future sysfs layout all
758 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
759 back to the "class" or the "bus". The layout of the parent devices in
760 /devices is not necessarily expected to be stable across kernel releases and
761 searching for parents by their subsystem should make sysfs users tolerant
762 for changed parent chains.
766 Prepare udev to work with the experimental kernel patch, that moves
767 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
769 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
770 moving the class devices to /sys/devices.
772 Thanks again to Marco for help finding a hopefully nice compromise
773 to make %b simpler and working again.
777 Complete removal of libsysfs, replaced by simple helper functions
778 which are much simpler and a bit faster. The udev daemon operatesentirely
779 on event parameters and does not use sysfs for simple rules anymore.
780 Please report any new bugs/problems, that may be caused by this big
781 change. They will be fixed immediately.
783 The enumeration format character '%e' is deprecated and will be
784 removed sometimes from a future udev version. It never worked correctly
785 outside of udevstart, so we can't use it with the new parallel
786 coldplug. A simple enumeration is as useless as the devfs naming
787 scheme, just get rid of both if you still use it.
789 MODALIAS and $modalias is not needed and will be removed from one of
790 the next udev versions, replace it in all rules with ENV{MODALIAS} or
791 the sysfs "modalias" value.
793 Thanks a lot to Marco for all his help on finding and fixing bugs.
797 Let scsi_id request libata drive serial numbers from page 0x80.
799 Renamed etc/udev/persistent.rules to persistent-disk.rules and
800 added /dev/disk/by-name/* for device mapper device names.
802 Removed %e from the man page. It never worked reliably outside
803 of udevstart and udevstart is no longer recommended to use.
807 Symlinks are now exported to the event environment. Hopefully it's no
808 longer needed to run udevinfo from an event process, like it was
809 mentioned on the hotplug list:
810 UDEV [1134776873.702967] add@/block/sdb
813 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
817 Fix a problem if udevsend is used as the hotplug handler and tries to use
818 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
819 and this kind of problems will hopefully go away soon.
823 All built-in logic to work around bad sysfs timing is removed with this
824 version. The need to wait for sysfs files is almost fixed with a kernel
825 version that doesn't work with this udev version anyway. Until we fix
826 the timing of the "bus" link creation, the former integrated logic should
827 be emulated by a rule placed before all other rules:
828 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
830 The option "udev_db" does no longer exist. All udev state will be in
831 /$udev_root/.udev/ now, there is no longer an option to set this
833 If the init script or something else used this value, just depend on
834 this hardcoded path. But remember _all_content_ of this directory is
835 still private to udev and can change at any time.
837 Default location for rule sripts and helper programs is now: /lib/udev/.
838 Everything that is not useful on the commandline should go into this
839 directory. Some of the helpers in the extras folder are installed there
840 now. The rules need to be changed, to find the helpers there.
842 Also /lib/udev/devices is recommended as a directory where packages or
843 the user can place real device nodes, which get copied over to /dev at
844 every boot. This should replace the various solutions with custom config
847 Udevsend does no longer start the udev daemon. This must be done with
848 the init script that prepares /dev on tmpfs and creates the initial nodes,
849 before starting the daemon.
853 Silent a too verbose error logging for the old hotplug.d/ dev.d/
856 The copy of klibc is removed. A systemwide installed version of klibc
857 should be used to build a klibc udev now.
861 NAME="" will not create any nodes, but execute RUN keys. To completely
862 ignore an event the OPTION "ignore_device" should be used.
864 After removal of the reorder queue, events with a TIMEOUT can be executed
865 without any queuing now.
869 Fixed bug in udevd, if inotify is not available. We depend on netlink
870 uevents now, kernels without that event source will not work with that
871 version of udev anymore.
875 The rule parsing happens now in the daemon once at startup, all udev
876 event processes inherit the already parsed rules from the daemon.
877 It is shipped with SUSE10.0 and reduces heavily the system load at
878 startup. The option to save precompiled rules and let the udev process
879 pick the them up is removed, as it's no longer needed.
881 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
882 device. Libsysfs is changed to "translate" the requested link into the
883 real device path, as it would happen with the hotplug event. Otherwise
884 device removal and the udev database will not work.
886 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
889 A few improvements for vol_id, the filesytem probing code.
893 Fix a stupid typo in extras/run_directory for "make install".
895 scsi_id creates the temporary devnode now in /dev for usage with a
896 non-writable /tmp directory.
898 The uevent kernel socket buffer can carry app. 50.000 events now,
899 let's see who can break this again. :)
901 The upcoming kernel will have a new input driver core integration.
902 Some class devices are now symlinks to the real device. libsysfs
903 needs a fix for this to work correctly. Udevstart of older udev
904 versions will _not_ create these devices!
908 Fix a 'install' target in the Makefile, that prevents EXTRAS from
913 A bunch of mostly trivial bugfixes. From now on no node name or
914 symlink name can contain any character than plain whitelisted ascii
915 characters or validated utf8 byte-streams. This is needed for the
916 /dev/disk/by-label/* links, because we import untrusted data and
917 export it to the filesystem.
921 More bugfixes. If udevd was started from the kernel, we don't
922 have stdin/stdout/stderr, which broke the forked tools in some
927 Bugfix. udevstart event ordering was broken for a long time.
928 The new run_program() uncovered it, because /dev/null was not
929 available while we try to run external programs.
930 Now udevstart should create it before we run anything.
934 Minor bugfixes and some distro rules updates. If you don't have the
935 persistent disk rules in /dev/disk/by-*/* on your distro, just
936 grab it from here. :)
940 We can use socket communication now to pass events from udev to
942 RUN+="socket:/org/freedesktop/hal/udev_event"
943 will pass the whole udev event to the HAL daemon without the need
944 for a forked helper. (See ChangeLog for udevmonitor, as an example)
948 Mostly bugfixes and see ChangeLog.
950 The test for the existence of an environment value should be
952 ENV{KEY}=="*" to ENV{KEY}=="?*"
953 because "*" will not fail anymore, if the key does not exist or
958 Bugfixes and a few tweaks described in the ChangeLog.
962 Mostly a Bugfix release.
964 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
965 timing with custom rules.
969 We changed the internal rule storage format. Our large rule files took
970 2 MB of RAM, with the change we are down to 99kB.
972 If the device-node has been created with default name and no symlink or
973 options are to remenber, it is not longer stored in the udevdb. HAL will
974 need to be updated to work correctly with that change.
976 To overrride optimization flags, OPTFLAGS may be used now.
984 Major changes happened with this release. The goal is to take over the
985 complete kernel-event handling and provide a more efficient way to dispatch
986 kernel events. Replacing most of the current shell script logic and the
987 kernel forked helper with a netlink-daemon and a rule-based event handling.
989 o udevd listens to netlink events now. The first valid netlink event
990 will make udevd ignore any message from udevsend that contains a
991 SEQNUM, to avoid duplicate events. The forked events can be disabled
993 echo "" > /proc/sys/kernel/hotplug
994 For full support, the broken input-subsytem needs to be fixed, not to
995 bypass the driver core.
997 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
998 removed from udev itself and must be emulated by calling small
999 helper binaries provided in the extras folder:
1000 make EXTRAS=extras/run_directory/
1001 will build udev_run_devd and udev_run_hotplugd, which can be called
1002 from a rule if needed:
1003 RUN+="/sbin/udev_run_hotplugd"
1004 The recommended way to handle this is to convert all the calls from
1005 the directories to explicit udev rules and get completely rid of the
1006 multiplexing. (To catch a ttyUSB event, you now no longer need to
1007 fork and exit 300 tty script instances you are not interested in, it
1008 is just one rule that matches exactly the device.)
1010 o udev handles now _all_ events not just events for class and block
1011 devices, this way it is possible to control the complete event
1012 behavior with udev rules. Especially useful for rules like:
1013 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1015 o As used in the modalias rule, udev supports now textual
1016 substitution placeholder along with the usual format chars. This
1017 needs to be documented, for now it's only visible in udev_rules_parse.c.
1019 o The rule keys support now more operations. This is documented in the
1020 man page. It is possible to add values to list-keys like the SYMLINK
1021 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1022 Also "final"-assignments are supported by using KEY:="value", which will
1023 prevent changing the key by any later rule.
1025 o kernel 2.6.12 has the "detached_state" attribute removed from
1026 sysfs, which was used to recognize sysfs population. We switched that
1027 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1028 Running this udev version on older kernels may cause a short delay for
1031 o To provide infrastructure for persistent device naming, the id programs:
1032 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1033 to export the probed data in environment key format:
1034 pim:~ # /sbin/ata_id --export /dev/hda
1035 ID_MODEL=HTS726060M9AT00
1036 ID_SERIAL=MRH401M4G6UM9B
1037 ID_REVISION=MH4OA6BA
1039 The following rules:
1040 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1041 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1044 kay@pim:~> tree /dev/disk
1047 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1048 | `-- IBM-Memory_Key -> ../../sda
1050 | |-- swap -> ../../hda1
1051 | |-- date -> ../../sda1
1052 | `-- home -> ../../hda3
1054 |-- 2E08712B0870F2E7 -> ../../hda3
1055 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1056 |-- E845-7A89 -> ../../sda1
1057 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1059 The IMPORT= operation will import these keys in the environment and make
1060 it available for later PROGRAM= and RUN= executed programs. The keys are
1061 also stored in the udevdb and can be queried from there with one of the
1064 o A few binaries are silently added to the repository, which can be used
1065 to replay kernel events from initramfs instead of using coldplug. udevd
1066 can be instructed now to queue-up events while the stored events from
1067 initramfs are filled into the udevd-queue. This code is still under
1068 development and there is no documentation now besides the code itself.
1069 The additional binaries get compiled, but are not installed by default.
1071 o There is also a temporary fix for a performance problem where too many
1072 events happen in parallel and every event needs to parse the rules.
1073 udev can now read precompiled rules stored on disk. This is likely to be
1074 replaced by a more elegant solution in a future udev version.
1078 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1079 Fix for libsysfs not to expect this file was added.
1083 All rules are applied now, but only the first matching rule with a NAME-key
1084 will be applied. All later rules with NAME-key are completely ignored. This
1085 way system supplied symlinks or permissions gets applied to user-defined
1089 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1090 to some rules, to keep the old behavior.
1092 The rules are read on "remove"-events too. That makes is possible to match
1093 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1094 instruct udev to ignore an event (OPTIONS="ignore_device").
1095 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1097 The new RUN-key supports rule-based execution of programs after device-node
1098 handling. This is meant as a general replacement for the dev.d/-directories
1099 to give fine grained control over the execution of programs.
1101 The %s{}-sysfs format char replacement values are searched at any of the
1102 devices in the device chain now, not only at the class-device.
1104 We support log priority levels now. The value udev_log in udev.conf is used
1105 to determine what is printed to syslog. This makes it possible to
1106 run a version with compiled-in debug messages in a production environment
1107 which is sometimes needed to find a bug.
1108 It is still possible to supress the inclusion of _any_ syslog usage with
1109 USE_LOG=false to create the smallest possible binaries if needed.
1110 The configured udev_log value can be overridden with the environment variable
1115 Possible use of a system-wide klibc:
1116 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1117 will link against an external klibc and our own version will be ignored.
1121 We support an unlimited count of symlinks now.
1123 If USE_STATIC=true is passed to a glibc build, we link statically and use
1124 a built-in userdb parser to resolve user and group names.
1126 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1127 we walk up the chain of physical devices to find a match.
1129 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1130 easy to skip certain attribute matches without composing rules with weird
1131 character class negations like:
1132 KERNEL="[!s][!c][!d]*"
1133 this can now be replaced with:
1135 The current simple '=' is still supported, and should work as it does today,
1136 but existing rules should be converted if possible, to be better readable.
1138 We have new ENV{}== key now, to match against a maximum of 5 environment
1141 udevstart is its own binary again, because we don't need co carry this araound
1142 with every forked event.