[bug#30498] [PATCH shepherd] shepherd: If /dev/kmsg is writable, use it for logging.

[Danny Milosavljevic]

It's nice to be able to correlate all the stuff that happens at startup now:

Now you can actually see the communication between the processes sometimes :)

Example output:

$ dmesg
...
[    2.893529] usb 1-6: Manufacturer: Chicony Electronics Co., Ltd.
[    3.056972] shepherd[1]: Service root has been started.
[    3.456744] shepherd[1]: starting services...
[    3.457110] shepherd[1]: Service root-file-system has been started.
[    3.466479] shepherd[1]: waiting for udevd...
[    3.522308] udevd[186]: starting version 3.2.2
[    3.574506] udevd[186]: starting eudev-3.2.2
[    3.967420] udevd[186]: no sender credentials received, message ignored
[    4.030350] Non-volatile memory driver v1.3
[    4.059448] thinkpad_acpi: ThinkPad ACPI Extras v0.25
...
[    5.298348] ath9k_htc 2-2:1.0 wlp0s29f7u2: renamed from wlan0
[    5.381098] fbcon: inteldrmfb (fb0) is primary device
[    5.938603] Console: switching to colour frame buffer device 160x50
[    5.958004] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[    5.993028] shepherd[1]: Service udev has been started.
[   10.953719] Btrfs loaded, crc32c=crc32c-generic
[   10.955704] BTRFS: device label dayas-home devid 1 transid 260833 /dev/dm-0
[   10.983703] shepherd[1]: Service device-mapping-dayas-home has been started.
[   10.984000] shepherd[1]: Service user-file-systems has been started.
[   11.049660] BTRFS info (device dm-0): disk space caching is enabled
[   11.049663] BTRFS info (device dm-0): has skinny extents
[   11.219716] BTRFS info (device dm-0): enabling ssd optimizations
[   11.236633] shepherd[1]: Service file-system-/home has been started.
[   11.237366] shepherd[1]: Service file-system-/dev/pts has been started.
[   11.237997] shepherd[1]: Service file-system-/dev/shm has been started.
[   11.238568] shepherd[1]: Service file-system-/gnu/store has been started.
[   11.239180] shepherd[1]: Service file-system-/run/systemd has been started.
[   11.239839] shepherd[1]: Service file-system-/run/user has been started.
[   11.240465] shepherd[1]: Service file-system-/sys/fs/cgroup has been started.
[   11.241261] shepherd[1]: Service file-system-/sys/fs/cgroup/elogind has been 
started.
[   16.538532] shepherd[1]: Respawning thermald.
...
[   21.862151] IPv6: ADDRCONF(NETDEV_CHANGE): wlp0s29f7u2: link becomes ready
[  345.176995] shepherd[1]: Respawning xorg-server.
[  345.178541] shepherd[1]: Service xorg-server has been started.
[  764.782498] perf: interrupt took too long (2526 > 2500), lowering 
kernel.perf_event_max_sample_rate to 79000