The engine covers most of the udev grammar but not all of it, and the
gaps are invisible until a rule silently does nothing. Write down what
is implemented and where it parts ways with udev(7), rather than
leaving people to infer it from a ruleset that happens to work. The
man page gets the directory precedence and a pointer to udev(7) and
the User's Guide, which hold the details.
Rename the menu entry to Device Manager while here, matching how the
watchdog daemon is listed.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
The udev parity gaps that were blocked on IPC -- settle, trigger,
info, queue introspection, runtime rule reload -- become bus methods.
keventd serves its own socket the way Finit serves /run/finit/bus:
brokerless, libink, one socket per daemon, no forwarding between the
two.
Settle(u) -> b parked until the queue drains or the timeout
passes; true when settled
Trigger(s, s) replay events, action + subsystem glob
Info(s) -> a{ss} /run/udev/data properties for a devpath
RulesReload() -> u re-read rules dirs, returns rule count
QueueEmpty (b), SeqnumProcessed (t) properties
DeviceProcessed (ss) signal after each fully handled event
The queue state is the highest kernel seqnum keventd has handled,
baselined at startup, against /sys/kernel/uevent_seqnum. keventd -S
now asks the running daemon first and falls back to seqnum polling.
In passive mode Trigger and RulesReload refuse. Adds
link_call_connection() for the park bookkeeping.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
When started with -c (the default when keventd is the device manager),
gate the pidfile on the kernel's uevent_seqnum having been stable for
200ms. Up to now ready signaling with the pidfile was done right after
coldplug() triggered the kernel to re-emit events, but before uev_run()
had drained any of them, so <pid/keventd> really only meant "listening
on netlink".
With the gate, services that depend on <pid/keventd> can now assume /dev
is populated and persistent symlinks are live.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Stop-gap "settle" equivalent of udevadm settle for migration scenarios.
Polls /sys/kernel/uevent_seqnum every 50ms and exits zero when the
sequence number has been stable for 200ms (or non-zero after -t SECONDS
timeout, default 30s).
This is racy by design -- a slow probe firing after we return still
races -- so the doc steers users toward dev/, class/, and bind/
conditions for any service they control. Settle is for legacy boot
scripts and init transitions where condition wiring isn't feasible.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
dev/<X> only fires when a device gets a /dev node, which leaves a lot of
embedded-relevant hardware uncoverable: DSA switch cores, IIO sensors,
LEDs, backlight, PHYs, regulators -- all live purely under sysfs.
Two new condition namespaces:
class/<subsystem>/<sysname> asserted on every sysfs class device add
(e.g. <class/leds/blue>)
driver/<name> asserted while the driver is bound to at
least one device (e.g. <driver/mt7530>)
A driver can bind to several devices, so driver/ conditions are
refcounted: asserted on first bind, cleared when the last device is
unbound.
dev_cond() is generalized into a static cond_emit(prefix, rel, set) so
class_cond() and driver_cond() share the same mkpath + symlink/erase
code. The name avoids colliding with src/cond.h's public cond_path()
helper (unrelated function that returns a condition's filesystem path).
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
keventd is the only thing in the tree that links libblkid, so a tree
that used to build now stops in configure with no hint of which package
to install. Say so where people look for dependencies, and give CI the
package it now needs.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Add 27 stock rules installed to /lib/udev/rules.d/. Rules invoking
/lib/udev/<helper> fall back to keventd builtins (path_id, usb_id,
blkid, hwdb, kmod, net_id, input_id) when the helper binary is absent;
user-supplied helpers in /lib/udev/ still take precedence.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Transform keventd from a power-supply monitor + basic hotplug handler into
a full udev-compatible device manager.
Rules engine (rules.c):
- Full .rules file parser covering all udev key types: ACTION, KERNEL,
SUBSYSTEM, DEVPATH, ENV, ATTR, SYSCTL, TAG, RESULT, PROGRAM, TEST,
parent-chain KERNELS/SUBSYSTEMS/ATTRS/DRIVERS, and more
- Pattern matching: plain string, fnmatch glob, and pipe-separated alternatives
- Operators: ==, !=, =, +=, -=, :=
- Assignments: NAME=, MODE=, OWNER=, GROUP=, SYMLINK+=, ENV{k}=, TAG+=, RUN+=
- IMPORT{program|file|builtin|parent|cmdline|db}=
- PROGRAM= with stdout capture for subsequent RESULT== matching
- GOTO=/LABEL= flow control
- Loads *.rules from /lib/udev/rules.d, /run/udev/rules.d, /etc/udev/rules.d
and an optional extra directory (-r DIR); reloads on SIGHUP
Builtin framework (builtin.c):
- kmod: load module by MODALIAS or explicit alias
- hwdb: match device against *.hwdb text files in udev hwdb dirs; builds
correct lookup key per subsystem — evdev:input:b*v*p*e* for input,
usb:v*p* for USB, raw modalias for PCI/platform
- path_id: build stable ID_PATH / ID_PATH_TAG from sysfs topology (PCI, USB,
ATA, NVMe, platform, ACPI, virtio)
- usb_id: read idVendor/idProduct/bcdDevice/serial from sysfs; look up
ID_VENDOR_FROM_DATABASE and ID_MODEL_FROM_DATABASE from usb.ids
(hwdata package) when available; silent fallback when absent
- input_id: classify input devices (keyboard, mouse, joystick, touchscreen,
touchpad) from evdev capability bitmasks in sysfs
- net_id: generate predictable names — MAC-based enx<mac> and PCI-slot-based
enp<bus>s<dev>[f<func>]
- blkid: probe filesystem type, UUID, and label via libblkid; sets ID_FS_*
and ID_PART_TABLE_* properties
Network interface renaming (uevent.c):
- netdev_add() renames interfaces via SIOCSIFNAME when a NAME= rule matched,
then sets the Finit dev/ condition on the final name; and any setup using
persistent interface naming via udev rules
Device node and symlink improvements (uevent.c):
- NAME=, MODE=, OWNER=, GROUP= overrides from matched rules applied at
mknod/chown time, falling back to the built-in permission table
- SYMLINK+= links from rules applied alongside built-in by-id/by-path links
Device property database (udevdb.c):
- Persist per-device E:/S:/I: records to /run/udev/data/ on ADD/CHANGE,
delete on REMOVE; IMPORT{db}= restores saved properties into event env
Build:
- libblkid (util-linux) is now required for keventd
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
This is a backwards compatible mode for users upgrading and not noticing
that keventd is now build by default.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Rewrite doc/keventd.md from a 14-line stub into comprehensive
documentation covering all features of the new unified keventd:
device node creation, persistent symlinks, firmware loading,
module loading, coldplug, conditions, and command-line usage.
Update doc/conditions.md to list keventd as the primary provider
of dev/* and sys/pwr/* conditions, with devmon as fallback when
an external device manager is used instead.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Joachim Wiberg