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<p class="MsoNormal">I have a program, init-jm, that forks and executes /usr/lib/systemd/systemd in the parent (using execl() ) while the child collects some stats in a loop.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The child sets its argv[0][0] to ‘@’.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">init-jm is invoked using the “init” kernel parameter on a switch-root system (it’s Fedora 41).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Can someone explain why systemd (PID 1) sends SIGHUP to the child?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This happens just before the statement log_execution_mode(&first_boot) is executed inside main().<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sending SIGHUP to the child seems to be particular to the re-execution of the systemd binary during switch-root because it is not sent when init-jm is invoked using “rdinit”.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-James M<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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