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>
When a rule references an absolute helper path (e.g. /lib/udev/fido_id,
/lib/udev/scsi_id) that the system does not ship and we have no matching
builtin either, return 1 from try_builtin_fallback() so the caller does
not fork /bin/sh on a binary that's known to be missing. Previously
each such uevent left a zombie 127 child for keventd's sigchld_cb to
reap -- harmless but noisy and wasteful at coldplug.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
modprobe_load() and run_program() used to temporarily restore the
default SIGCHLD handler around fork+waitpid because the main loop set
SIGCHLD=SIG_IGN. With the libuev conversion, sigchld_cb in keventd.c
handles reaping via signalfd -- and signalfd does not interfere with
synchronous waitpid(pid, ...) -- so the dance is dead code.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Replace the raw poll() + global running/reload_rules flag dance with
libuev. All four signals (SIGUSR1, SIGTERM, SIGHUP, SIGCHLD) are now
handled via uev_signal_init() -- libuev uses signalfd internally so the
handlers run in normal main-loop context, not async signal context.
The SIGCHLD handler waitpid(-1, WNOHANG) reaps any subprocess (modprobe
loads, rule RUN+= helpers) instead of the old SIG_IGN auto-reap trick.
Synchronous waitpid() in modprobe_load() and run_program() still works
because signalfd queues the signal -- it only reaches sigchld_cb on the
next main-loop iteration.
The netlink receive loop becomes uevent_cb() registered via uev_io_init(),
with the receive buffer passed via the watcher's arg slot (avoids
file-static state). ENOBUFS and EINTR/EAGAIN are still tolerated, any
other recv() error still panic()s.
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>
Joachim Wiberg