[systemd-devel] issuing 'reboot' command does not print the familiar 'Restarting system.' message

[Ani Sinha]

Thanks Lennart for the clarification. Much appreciated!

Ani


On Fri, Apr 10, 2015 at 8:58 AM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Fri, 10.04.15 08:40, Ani Sinha (ani at arista.com) wrote:
>
>> On Fri, Apr 10, 2015 at 1:13 AM, Daniel Mack <daniel at zonque.org> wrote:
>> > On 04/10/2015 04:18 AM, Ani Sinha wrote:
>> >> OK I have one more question. Does every call path in the reboot
>> >> command use the Linux reboot() sys call? I'm not familiar with dbus
>> >> stuff but looking at the code seems to indicate that there might be
>> >> some paths where reboot() is not issued. Just wanted to run by you
>> >> guys since you guys know the code best.
>> >
>> > The reboot command is symlinked to systemctl, which is a multi-call
>> > binary. When invoked as 'reboot', 'shutdown', 'halt', 'poweroff' etc, it
>> > communicates with PID1 and tells it to start one of the shutdown
>> > targets. This way, the system will shut down and stop services in a
>> > clean way. Once the target is reached, the reboot() syscall is issued to
>> > the kernel.
>>
>> Can you please point me to the code and function call that processes
>> the 'reboot' target from PID 1?
>
> reboot.target pulls in systemd-reboot.service, which wraps
> "/usr/bin/systemctl --force reboot", which issues the Reboot() call on
> PID1's bus API, which causes it to execute /usr/lib/systemd-shutdown
> as PID 1 which then kills everything and reboots.
>
> Lennart
>
> --
> Lennart Poettering, Red Hat