5 Libudev allows to subscribe to udev events. To prevent unwanted messages
6 to be delivered, and waking up the subscribing process, a filter can be
7 installed, to drop messages inside a kernel socket filter. The filters
8 match on the <subsytem>:<devtype> properties of the device.
9 This is part of the ongoing effort to replace HAL, and switch current
10 users over to directly use libudev, or for higher-level services use the
11 specialized D-Bus interface of a DeviceKit service.
12 Libudev is still marked as experimental, and its interface might
13 change if needed, but no major changes of the currently exported interface
14 are expected anymore, and a first stable release should happen soon.
16 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
17 is not supported since while and udevd will log an error message at
20 DVB device naming is supplied by the kernel now. In case older kernels
21 need to be supported, the old shell script should be added to a compat
28 The processed udev events get send back to the netlink socket. Libudev
29 provides access to these events. This is work-in-progress, to replace
30 the DeviceKit daemon functionality directly with libudev. There are
31 upcoming kernel changes to allow non-root users to subcribe to these
38 "udevadm settle" now optionally accepts a range of events to wait for,
39 instead of waiting for "all" events.
45 The installed watch for block device metadata changes is now removed
46 during event hadling, because some (broken) tools may be called from udev
47 rules and (wrongly) open the device with write access. After the finished
48 event handling the watch is restored.
54 Device nodes can be watched for changes with inotify with OPTIONS="watch".
55 If closed after being opened for writing, a "change" uevent will occur.
56 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
62 The udevadm test command has no longer a --force option, nodes and symlinks
63 are always updated with a test run now.
65 The udevd daemon can be started with --resolve-names=never to avoid all user
66 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
67 lookup user and groups every time events are handled.
73 We are currently merging the Ubuntu rules in the udev default rules,
74 and get one step closer to provide a common Linux /dev setup, regarding
75 device names, symlinks, and default device permissions. On udev startup,
76 we now expect the following groups to be resolvable to their ids with
78 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
79 LDAP setups need to make sure, that these groups are always resolvable at
80 bootup, with only the rootfs mounted, and without network access available.
82 Some systems may need to add some new, currently not used groups, or need
83 to add some users to new groups, but the cost of this change is minimal,
84 compared to the pain the current, rather random, differences between the
85 various distributions cause for upstream projects and third-party vendors.
87 In general, "normal" users who log into a machine should never be a member
88 of any such group, but the device-access should be managed by dynamic ACLs,
89 which get added and removed for the specific users on login/logout and
90 session activity/inactivity. These groups are only provided for custom setups,
91 and mainly system services, to allow proper privilege separation.
92 A video-streaming daemon uid would be a member of "audio" and "video", to get
93 access to the sound and video devices, but no "normal" user should ever belong
94 to the "audio" group, because he could listen to the built-in microphone with
95 any ssh-session established from the other side of the world.
97 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
98 which do not depend on the kernel device name. As usual, unique
99 devices - only a single one per product connected, or a real
100 USB serial number in the device - are always found with the same
101 name in the by-id/ directory.
102 Completely identical devices may overwrite their names in by-id/
103 and can only be found reliably in the by-path/ directory. Devices
104 specified by by-path/ must not change their connection, like the
105 USB port number they are plugged in, to keep their name.
107 To support some advanced features, Linux 2.6.22 is the oldest supported
108 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
109 supported. Older kernels should still work, and devices nodes should be
110 reliably created, but some rules and libudev will not work correctly because
111 the old kernels do not provide the expected information or interfaces.
117 Fix for a possible segfault while swapping network interface names in udev
124 The group "video" is part of the default rules now.
128 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
129 block devices in some cases. No common distro uses this option anymore,
130 and we do not get enough testing for this and recent udev versions. If
131 this option is not needed to run some old distro with a new kernel,
132 it should be disabled in the kernel config.
134 Bugfix for the $links substitution variable, which may crash if no links
135 are created. This should not happen in usual setups because we always
136 create /dev/{block,char}/ links.
138 The strings of the parsed rules, which are kept in memory, no longer
139 contain duplicate entries, or duplicate tails of strings. This, and the
140 new rules parsing/matching code reduces the total in-memory size of
141 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
144 The export of DEVTYPE=disk/partition got removed from the default
145 rules. This value is available from the kernel. The pnp shell script
146 modprobe hack is removed from the default rules. ACPI devices have _proper_
147 modalias support and take care of the same functionality.
148 Installations which support old kernels, but install current default
149 udev rules may want to add that to the compat rules file.
151 Libvolume_id now always probes for all known filesystems, and does not
152 stop at the first match. Some filesystems are marked as "exclusive probe",
153 and if any other filesytem type matches at the same time, libvolume_id
154 will, by default, not return any probing result. This is intended to prevent
155 mis-detection with conflicting left-over signatures found from earlier
156 file system formats. That way, we no longer depend on the probe-order
157 in case of multiple competing signatures. In some setups the kernel allows
158 to mount a volume with just the old filesystem signature still in place.
159 This may damage the new filesystem and cause data-loss, just by mounting
160 it. Because volume_id can not decide which one the correct signature is,
161 the wrong signatures need to be removed manually from the volume, or the
162 volume needs to be reformatted, to enable filesystem detection and possible
167 Fix segfault if compiled without optimization and dbg() does not get
168 compiled out and uses variables which are not available.
172 Bugfixes. (And maybe new bugs. :))
174 The rule matching engine got converted from a rule list to a token
175 array which reduced the in-memory rules representation of a full
176 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
177 Limits like 5 ENV and ATTR matches, and one single instance for most
178 other keys per rule are gone.
180 The NAME assignment is no longer special cased. If later rules assign
181 a NAME value again, the former value will be overwritten. As usual
182 for most other keys, the NAME value can be protected by doing a final
183 assignment with NAME:="<value>".
185 All udev code now uses libudev, which is also exported. The library
186 is still under development, marked as experimental, and its interface
187 may change as long as the DeviceKit integration is not finished.
189 Many thanks to Alan Jenkins for his continuous help, and finding and
190 optimizing some of the computing expensive parts.
196 Kernel devices and device nodes are connected now by reverse indizes in
197 /sys and /dev. A device number retrieved by a stat() or similar, the
198 kernel device directory can be found by looking up:
199 /sys/dev/{block,char}/<maj>:<min>
200 and the device node of the same device by looking up:
201 /dev/{block,char}/<maj>:<min>
205 Fix recently introduced bug, which caused a compilation without large
206 file support, where vol_id does not recognize raid signatures at the end
209 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
210 Seems some kernel versions prevent the creation of the ieee-* links,
211 so people used the scsi-* link which disappeared now.
213 More libudev work. Almost all udevadm functionality comes from libudev
216 udevadm trigger has a new option --type, which allows to trigger events
217 for "devices", for "subsystems", or "failed" devices. The old option
218 --retry-failed" still works, but is no longer mentioned in the man page.
224 The udevadm info --device-id-of-file= output has changed to use
225 the obvious format. Possible current users should use the --export
226 option which is not affected.
228 The old udev commands symlinks to udevadm are not installed, if
229 these symlinks are used, a warning is printed.
235 Optical drive's media is no longer probed for raid signatures,
236 reading the end of the device causes some devices to malfunction.
237 Also the offset of the last session found is used now to probe
240 The volume_id library got a major version number update to 1,
241 some deprecated functions are removed.
243 A shared library "libudev" gets installed now to provide access
244 to udev device information. DeviceKit, the successor of HAL, will
245 need this library to access the udev database and search sysfs for
247 The library is currently in an experimental state, also the API is
248 expected to change, as long as the DeviceKit integration is not
253 We use ./configure now. See INSTALL for details. Current
256 "/usr" - prefix for man pages, include files
258 "" - the root filesystem, prefix for libs and binaries
262 "lib" - directory name for libraries, not a path name
263 multilib 64bit systems may use "lib64" instead of "lib"
265 compile-in verbose debug messages
267 disable all logging and compile-out all log strings
269 link against SELInux libraries, to set the expected context
272 In the default rules, the group "disk" gets permissions 0660 instead
273 of 0640. One small step closer to unify distro rules. Some day, all
274 distros hopefully end up with the same set of rules.
276 No symlinks to udevadm are installed anymore, if they are still needed,
277 they should be provided by the package.
283 Default udev rules, which are not supposed to be edited by the user, should
284 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
285 the udev package and will be replaced with an update. Udev will pick up rule
287 /lib/udev/rules.d/ - default installed rules
288 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
289 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
290 It does not matter in which directory a rule file lives, all files are sorted
293 To help creating /dev/root, we have now:
294 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
297 In case the current --device-id-of-file is already used, please switch to
298 the --export format version, it saves the output parsing and the old
299 format will be changed to use ':' as a separator, like the format in the
304 Fix cdrom_id to properly recognize blank media.
310 Tape drive id-data is queried from /dev/bsg/* instead of the tape
311 nodes. This avoids rewinding tapes on open().
317 The symlinks udevcontrol and udevtrigger are no longer installed by
320 The scsi_id program does not depend on sysfs anymore. It can speak
321 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
322 data, which should solve some old problems with tape devices, where
323 we better do not open all tape device nodes to identify the device.
329 The cdrom_id program is replaced by an advanced version, which can
330 detect most common device types, and also properties of the inserted
331 media. This is part of moving some basic functionality from HAL into
332 udev (and the kernel).
338 The last WAIT_FOR_SYSFS rule is removed from the default rules.
340 The symlinks to udevadm for the debugging tools: udevmonitor and
341 udevtest are no longer created.
343 The symlinks to the udevadm man page for the old tool names are
346 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
347 should be prefixed with '@' to indicate that the path is not a
358 Udevstart is removed from the tree, it did not get installed for
359 a long time now, and is long replaced by trigger and settle.
365 All udev tools are merged into a single binary called udevadm.
366 The old names of the tools are built-in commands in udevadm now.
367 Symlinks to udevadm, with the names of the old tools, provide
368 the same functionality as the standalone tools. There is also
369 only a single udevadm.8 man page left for all tools.
371 Tools like mkinitramfs should be checked, if they need to include
372 udevadm in the list of files.
382 The etc/udev/rules.d/ directory now contains a default set of basic
383 udev rules. This initial version is the result of a rules file merge
384 of Fedora and openSUSE. For these both distros only a few specific
385 rules are left in their own file, named after the distro. Rules which
386 are optionally installed, because they are only valid for a specific
387 architecture, or rules for subsystems which are not always used are
388 in etc/udev/packages/.
394 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
395 actions by dynamically created rules.
397 SYMLINK=="<value>" matches agains the entries in the list of
398 currently defined symlinks. The links are not created in the
399 filesystem at that point in time, but the values can be matched.
401 RUN{ignore_error}+="<program>" will ignore any exit code from the
402 program and not record as a failed event.
408 Final merge of patches/features from the Ubuntu package.
414 Control characters in filesystem label strings are no longer silenty
415 removed, but hex-encoded, to be able to uniquely identify the device
416 by its symlink in /dev/disk/by-label/.
417 If libvolume_id is used by mount(8), LABEL= will work as expected,
418 if slashes or other characters are used in the label string.
420 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
421 can be specified now. The TEST key accepts an optional mode mask
422 TEST{0100}=="<is executable file>".
424 Scsi_id now supports a mode without expecting scsi-specific sysfs
425 entries to allow the extraction of cciss-device persistent properties.
431 In the future, we may see uuid's which are just simple character
432 strings (see the DDF Raid Specification). For that reason vol_id now
433 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
434 the creation of symlinks, the *_SAFE values ensure, that no control
435 or whitespace characters are used in the filename.
437 Possible users of libvolume_id, please use the volume_id_get_* functions.
438 The public struct will go away in a future release of the library.
444 Removal of useless extras/eventrecorder.sh.
454 The directory multiplexer for dev.d/ and hotplug.d are finally removed
455 from the udev package.
461 Symlinks can have priorities now, the priority is assigned to the device
462 and specified with OPTIONS="link_priority=100". Devices with higher
463 priorities overwrite the symlinks of devices with lower priorities.
464 If the device that currently owns the link, goes away, the symlink
465 will be removed, and recreated, pointing to the next device with the
466 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
467 more reliable, if multiple devices contain the same metadata and overwrite
470 The dasd_id program is removed from the udev tree, and dasdinfo, with the
471 needed rules, are part of the s390-tools now.
473 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
474 we may get the scsi sysfs mess fixed some day, and this will only catch
475 the devices we are looking for.
477 USB serial numbers for storage devices have the target:lun now appended,
478 to make it possibble to distinguish broken multi-lun devices with all
479 the same SCSI identifiers.
481 Note: The extra "run_directory" which searches and executes stuff in
482 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
483 with the next release. Make sure, that you don't use it anymore, or
484 provides your own implementation of that inefficient stuff.
485 We are tired of reports about a "slow udev", because these directories
486 contain stuff, that runs with _every_ event, instead of using rules,
487 that run programs only for the matching events.
497 DRIVER== will match only for devices that actually have a real
498 driver. DRIVERS== must be used, if parent devices should be
499 included in the match.
501 Libvolume_id's "linux_raid" detection needed another fix.
509 Add additional check to volume_id detection of via_raid, cause
510 some company decided to put a matching pattern all over the empty
511 storage area of their music players.
515 Fix path_id for SAS devices.
519 The udev daemon can be started with --debug-trace now, which will
520 execute all events serialized to get a chance to catch a possible
521 action that crashes the box.
523 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
524 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
525 are excluded from the warning. Referencing parent attributes directly
526 may break when something in the kernel driver model changes. Udev will
527 just find the attribute by walking up the parent chain.
529 Udevtrigger now sorts the list of devices depending on the device
530 dependency, so a "usb" device is triggered after the parent "pci"
535 Revert persistent-storage ata-serial '_' '-' replacement.
541 Udevtrigger can now filter the list of devices to be triggered. Matches
542 for subsystems or sysfs attributes can be specified.
544 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
545 zero-sized files to avoid pointing to /sys and confuse broken tools which
546 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
549 The rules and scripts to create udev rules for persistent network
550 devices and optical drives are in the extras/rules_generator directory
551 now. If you use something similar, please consider replacing your own
552 version with this, to share the support effort. The rule_generator
553 installs its own rules into /etc/udev/rules.d.
555 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
556 the rule_generator depends on cdrom_id to be called in an earlier rule.
562 Renaming of some key names (the old names still work):
563 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
564 (The behavior of the key DRIVER will change soon in one of the next
565 releases, to match only the event device, please switch to DRIVERS
566 instead. If DRIVER is used, it will behave like DRIVERS, but an error
568 With the new key names, we have a more consistent and simpler scheme.
569 We can match the properties of the event device only, with: KERNEL,
570 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
571 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
572 longer mentioned in the man page and should be switched in the rule
575 ATTR{file}="value" can be used now, to write to a sysfs file of the
576 event device. Instead of:
577 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
579 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
581 All the PHYSDEV* keys are deprecated and will be removed from a
583 PHYDEVPATH - is the path of a parent device and should not be
585 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
586 matched with SUBSYSTEMS==
587 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
588 Newer kernels will have DRIVER in the environment,
589 for older kernels udev puts in. Class device will
590 no longer carry this property of a parent and
591 DRIVERS== can be used to match such a parent value.
592 Note that ENV{DRIVER} is only available for a few bus devices, where
593 the driver is already bound at device event time. On coldplug, the
594 events for a lot devices are already bound to a driver, and they will have
595 that value set. But on hotplug, at the time the kernel creates the device,
596 it can't know what driver may claim the device after that, therefore
597 in most cases it will be empty.
599 Failed events should now be re-triggered with:
600 udevtrigger --retry-failed.
601 Please switch to this command, so we keep the details of the /dev/.udev/failed/
602 files private to the udev tools. We may need to switch the current symlink
603 target, cause some obviously broken tools try to scan all files in /dev
604 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
605 million times. This takes ages on slow boxes.
607 The udevinfo attribute walk (-a) now works with giving a device node
608 name (-n) instead of a devpath (-p). The query now always works, also when
609 no database file was created by udev.
611 The built-in /etc/passwd /etc/group parser is removed, we always depend on
612 getpwnam() and getgrnam() now. One of the next releases will depend on
613 fnmatch() and may use getopt_long().
617 Bugfixes and small improvements.
621 Fix path_id for recent kernels.
627 Added support for swapping network interface names, by temporarily
628 renaming the device and wait for the target name to become free.
632 The built-in MODALIAS key and substitution is removed.
636 The binary firmware helper is replaced by the usual simple
637 shell script. Udevsend is removed from the tree.
645 Some more keys require the correct use of '==' and '=' depending
646 on the kind of operation beeing an assignment or a match. Rules
647 with invalid operations are skipped and logged to syslog. Please
648 test with udevtest if the parsing of your rules throws errors and
649 fix possibly broken rules.
653 Provide "udevsettle" to wait for all current udev events to finish.
654 It also watches the current kernel netlink queue by comparing the
655 even sequence number to make sure that there are no current pending
656 events that have not already arrived in the daemon.
660 Fix rule to skip persistent rules for removable IDE devices, which
661 also skipped optical IDE drives.
663 All *_id program are installed in /lib/udev/ by default now.
665 No binary is stripped anymore as this should be done in the
666 packaging process and not at build time.
668 libvolume_id is provided as a shared library now and vol_id is
669 linked against it. Also one of the next HAL versions will require
670 this library, and the HAL build process will also require the
671 header file to be installed. The copy of the same code in HAL will
672 be removed to have only a single copy left on the system.
676 Add persistent links for SCSI tapes. The rules file is renamed
677 to 60-persistent-storage.rules.
679 Create persistent path for usb devices. Can be used for all sorts
680 of devices that can't be distinguished by other properties like
681 multiple identical keyboards and mice connected to the same box.
683 Provide "udevtrigger" program to request events on coldplug. The
684 shell script is much too slow with thousends of devices.
688 Fix persistent disk rules to exclude removable IDE drives.
690 Warn if %e, $modalias or MODALIAS is used.
694 Fix queue export, which wasn't correct for subsequent add/remove
695 events for the same device.
699 Fix cramfs detection on big endian.
701 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
706 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
707 attributes were only checked at the parent device that matched the
708 by BUS requested subsystem. Fix it to also look at the device we
709 received the event for.
711 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
716 Fix a bug where NAME="" would prevent RUN from beeing executed.
718 RUN="/bin/program" does not longer automatically add the subsystem
719 as the first parameter. This is from the days of /sbin/hotplug
720 which is dead now and it's just confusing to need to add a space at
721 the end of the program name to prevent this.
722 If you use rules that need the subsystem as the first parameter,
723 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
724 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
728 The udev man page has moved to udev(7) as it does not describe a command
729 anymore. The programs udev, udevstart and udevsend are no longer installed
730 by default and must be copied manually, if they should be installed or
731 included in a package.
733 Fix a bug where "ignore_device" could run earlier collected RUN keys before
734 the ignore rule was applied.
736 More preparation for future sysfs changes. usb_id and scsi_id no longer
737 depend on a magic order of devices in the /devices chain. Specific devices
738 should be requested by their subsytem.
740 This will always find the scsi parent device without depending on a specific
742 dev = sysfs_device_get(devpath);
743 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
745 The "device" link in the current sysfs layout will be automatically
746 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
747 parent in the devpath. If a device is requested by it's symlink, like all
748 class devices in the new sysfs layout will look like, it gets automatically
749 resolved and substituted with the real devpath and not the symlink path.
752 A similar logic must be applied to _all_ sysfs users, including
753 scripts, that search along parent devices in sysfs. The explicit use of
754 the "device" link must be avoided. With the future sysfs layout all
755 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
756 back to the "class" or the "bus". The layout of the parent devices in
757 /devices is not necessarily expected to be stable across kernel releases and
758 searching for parents by their subsystem should make sysfs users tolerant
759 for changed parent chains.
763 Prepare udev to work with the experimental kernel patch, that moves
764 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
766 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
767 moving the class devices to /sys/devices.
769 Thanks again to Marco for help finding a hopefully nice compromise
770 to make %b simpler and working again.
774 Complete removal of libsysfs, replaced by simple helper functions
775 which are much simpler and a bit faster. The udev daemon operatesentirely
776 on event parameters and does not use sysfs for simple rules anymore.
777 Please report any new bugs/problems, that may be caused by this big
778 change. They will be fixed immediately.
780 The enumeration format character '%e' is deprecated and will be
781 removed sometimes from a future udev version. It never worked correctly
782 outside of udevstart, so we can't use it with the new parallel
783 coldplug. A simple enumeration is as useless as the devfs naming
784 scheme, just get rid of both if you still use it.
786 MODALIAS and $modalias is not needed and will be removed from one of
787 the next udev versions, replace it in all rules with ENV{MODALIAS} or
788 the sysfs "modalias" value.
790 Thanks a lot to Marco for all his help on finding and fixing bugs.
794 Let scsi_id request libata drive serial numbers from page 0x80.
796 Renamed etc/udev/persistent.rules to persistent-disk.rules and
797 added /dev/disk/by-name/* for device mapper device names.
799 Removed %e from the man page. It never worked reliably outside
800 of udevstart and udevstart is no longer recommended to use.
804 Symlinks are now exported to the event environment. Hopefully it's no
805 longer needed to run udevinfo from an event process, like it was
806 mentioned on the hotplug list:
807 UDEV [1134776873.702967] add@/block/sdb
810 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
814 Fix a problem if udevsend is used as the hotplug handler and tries to use
815 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
816 and this kind of problems will hopefully go away soon.
820 All built-in logic to work around bad sysfs timing is removed with this
821 version. The need to wait for sysfs files is almost fixed with a kernel
822 version that doesn't work with this udev version anyway. Until we fix
823 the timing of the "bus" link creation, the former integrated logic should
824 be emulated by a rule placed before all other rules:
825 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
827 The option "udev_db" does no longer exist. All udev state will be in
828 /$udev_root/.udev/ now, there is no longer an option to set this
830 If the init script or something else used this value, just depend on
831 this hardcoded path. But remember _all_content_ of this directory is
832 still private to udev and can change at any time.
834 Default location for rule sripts and helper programs is now: /lib/udev/.
835 Everything that is not useful on the commandline should go into this
836 directory. Some of the helpers in the extras folder are installed there
837 now. The rules need to be changed, to find the helpers there.
839 Also /lib/udev/devices is recommended as a directory where packages or
840 the user can place real device nodes, which get copied over to /dev at
841 every boot. This should replace the various solutions with custom config
844 Udevsend does no longer start the udev daemon. This must be done with
845 the init script that prepares /dev on tmpfs and creates the initial nodes,
846 before starting the daemon.
850 Silent a too verbose error logging for the old hotplug.d/ dev.d/
853 The copy of klibc is removed. A systemwide installed version of klibc
854 should be used to build a klibc udev now.
858 NAME="" will not create any nodes, but execute RUN keys. To completely
859 ignore an event the OPTION "ignore_device" should be used.
861 After removal of the reorder queue, events with a TIMEOUT can be executed
862 without any queuing now.
866 Fixed bug in udevd, if inotify is not available. We depend on netlink
867 uevents now, kernels without that event source will not work with that
868 version of udev anymore.
872 The rule parsing happens now in the daemon once at startup, all udev
873 event processes inherit the already parsed rules from the daemon.
874 It is shipped with SUSE10.0 and reduces heavily the system load at
875 startup. The option to save precompiled rules and let the udev process
876 pick the them up is removed, as it's no longer needed.
878 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
879 device. Libsysfs is changed to "translate" the requested link into the
880 real device path, as it would happen with the hotplug event. Otherwise
881 device removal and the udev database will not work.
883 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
886 A few improvements for vol_id, the filesytem probing code.
890 Fix a stupid typo in extras/run_directory for "make install".
892 scsi_id creates the temporary devnode now in /dev for usage with a
893 non-writable /tmp directory.
895 The uevent kernel socket buffer can carry app. 50.000 events now,
896 let's see who can break this again. :)
898 The upcoming kernel will have a new input driver core integration.
899 Some class devices are now symlinks to the real device. libsysfs
900 needs a fix for this to work correctly. Udevstart of older udev
901 versions will _not_ create these devices!
905 Fix a 'install' target in the Makefile, that prevents EXTRAS from
910 A bunch of mostly trivial bugfixes. From now on no node name or
911 symlink name can contain any character than plain whitelisted ascii
912 characters or validated utf8 byte-streams. This is needed for the
913 /dev/disk/by-label/* links, because we import untrusted data and
914 export it to the filesystem.
918 More bugfixes. If udevd was started from the kernel, we don't
919 have stdin/stdout/stderr, which broke the forked tools in some
924 Bugfix. udevstart event ordering was broken for a long time.
925 The new run_program() uncovered it, because /dev/null was not
926 available while we try to run external programs.
927 Now udevstart should create it before we run anything.
931 Minor bugfixes and some distro rules updates. If you don't have the
932 persistent disk rules in /dev/disk/by-*/* on your distro, just
933 grab it from here. :)
937 We can use socket communication now to pass events from udev to
939 RUN+="socket:/org/freedesktop/hal/udev_event"
940 will pass the whole udev event to the HAL daemon without the need
941 for a forked helper. (See ChangeLog for udevmonitor, as an example)
945 Mostly bugfixes and see ChangeLog.
947 The test for the existence of an environment value should be
949 ENV{KEY}=="*" to ENV{KEY}=="?*"
950 because "*" will not fail anymore, if the key does not exist or
955 Bugfixes and a few tweaks described in the ChangeLog.
959 Mostly a Bugfix release.
961 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
962 timing with custom rules.
966 We changed the internal rule storage format. Our large rule files took
967 2 MB of RAM, with the change we are down to 99kB.
969 If the device-node has been created with default name and no symlink or
970 options are to remenber, it is not longer stored in the udevdb. HAL will
971 need to be updated to work correctly with that change.
973 To overrride optimization flags, OPTFLAGS may be used now.
981 Major changes happened with this release. The goal is to take over the
982 complete kernel-event handling and provide a more efficient way to dispatch
983 kernel events. Replacing most of the current shell script logic and the
984 kernel forked helper with a netlink-daemon and a rule-based event handling.
986 o udevd listens to netlink events now. The first valid netlink event
987 will make udevd ignore any message from udevsend that contains a
988 SEQNUM, to avoid duplicate events. The forked events can be disabled
990 echo "" > /proc/sys/kernel/hotplug
991 For full support, the broken input-subsytem needs to be fixed, not to
992 bypass the driver core.
994 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
995 removed from udev itself and must be emulated by calling small
996 helper binaries provided in the extras folder:
997 make EXTRAS=extras/run_directory/
998 will build udev_run_devd and udev_run_hotplugd, which can be called
999 from a rule if needed:
1000 RUN+="/sbin/udev_run_hotplugd"
1001 The recommended way to handle this is to convert all the calls from
1002 the directories to explicit udev rules and get completely rid of the
1003 multiplexing. (To catch a ttyUSB event, you now no longer need to
1004 fork and exit 300 tty script instances you are not interested in, it
1005 is just one rule that matches exactly the device.)
1007 o udev handles now _all_ events not just events for class and block
1008 devices, this way it is possible to control the complete event
1009 behavior with udev rules. Especially useful for rules like:
1010 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1012 o As used in the modalias rule, udev supports now textual
1013 substitution placeholder along with the usual format chars. This
1014 needs to be documented, for now it's only visible in udev_rules_parse.c.
1016 o The rule keys support now more operations. This is documented in the
1017 man page. It is possible to add values to list-keys like the SYMLINK
1018 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1019 Also "final"-assignments are supported by using KEY:="value", which will
1020 prevent changing the key by any later rule.
1022 o kernel 2.6.12 has the "detached_state" attribute removed from
1023 sysfs, which was used to recognize sysfs population. We switched that
1024 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1025 Running this udev version on older kernels may cause a short delay for
1028 o To provide infrastructure for persistent device naming, the id programs:
1029 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1030 to export the probed data in environment key format:
1031 pim:~ # /sbin/ata_id --export /dev/hda
1032 ID_MODEL=HTS726060M9AT00
1033 ID_SERIAL=MRH401M4G6UM9B
1034 ID_REVISION=MH4OA6BA
1036 The following rules:
1037 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1038 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1041 kay@pim:~> tree /dev/disk
1044 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1045 | `-- IBM-Memory_Key -> ../../sda
1047 | |-- swap -> ../../hda1
1048 | |-- date -> ../../sda1
1049 | `-- home -> ../../hda3
1051 |-- 2E08712B0870F2E7 -> ../../hda3
1052 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1053 |-- E845-7A89 -> ../../sda1
1054 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1056 The IMPORT= operation will import these keys in the environment and make
1057 it available for later PROGRAM= and RUN= executed programs. The keys are
1058 also stored in the udevdb and can be queried from there with one of the
1061 o A few binaries are silently added to the repository, which can be used
1062 to replay kernel events from initramfs instead of using coldplug. udevd
1063 can be instructed now to queue-up events while the stored events from
1064 initramfs are filled into the udevd-queue. This code is still under
1065 development and there is no documentation now besides the code itself.
1066 The additional binaries get compiled, but are not installed by default.
1068 o There is also a temporary fix for a performance problem where too many
1069 events happen in parallel and every event needs to parse the rules.
1070 udev can now read precompiled rules stored on disk. This is likely to be
1071 replaced by a more elegant solution in a future udev version.
1075 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1076 Fix for libsysfs not to expect this file was added.
1080 All rules are applied now, but only the first matching rule with a NAME-key
1081 will be applied. All later rules with NAME-key are completely ignored. This
1082 way system supplied symlinks or permissions gets applied to user-defined
1086 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1087 to some rules, to keep the old behavior.
1089 The rules are read on "remove"-events too. That makes is possible to match
1090 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1091 instruct udev to ignore an event (OPTIONS="ignore_device").
1092 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1094 The new RUN-key supports rule-based execution of programs after device-node
1095 handling. This is meant as a general replacement for the dev.d/-directories
1096 to give fine grained control over the execution of programs.
1098 The %s{}-sysfs format char replacement values are searched at any of the
1099 devices in the device chain now, not only at the class-device.
1101 We support log priority levels now. The value udev_log in udev.conf is used
1102 to determine what is printed to syslog. This makes it possible to
1103 run a version with compiled-in debug messages in a production environment
1104 which is sometimes needed to find a bug.
1105 It is still possible to supress the inclusion of _any_ syslog usage with
1106 USE_LOG=false to create the smallest possible binaries if needed.
1107 The configured udev_log value can be overridden with the environment variable
1112 Possible use of a system-wide klibc:
1113 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1114 will link against an external klibc and our own version will be ignored.
1118 We support an unlimited count of symlinks now.
1120 If USE_STATIC=true is passed to a glibc build, we link statically and use
1121 a built-in userdb parser to resolve user and group names.
1123 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1124 we walk up the chain of physical devices to find a match.
1126 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1127 easy to skip certain attribute matches without composing rules with weird
1128 character class negations like:
1129 KERNEL="[!s][!c][!d]*"
1130 this can now be replaced with:
1132 The current simple '=' is still supported, and should work as it does today,
1133 but existing rules should be converted if possible, to be better readable.
1135 We have new ENV{}== key now, to match against a maximum of 5 environment
1138 udevstart is its own binary again, because we don't need co carry this araound
1139 with every forked event.
~ianmdlvl / elogind.git / blob