From 02a071125de739ed54660ad014ffd57c42516abf Mon Sep 17 00:00:00 2001 From: PS Date: Sat, 7 Feb 2026 10:37:36 +0100 Subject: Add doc --- doc/service/system/.s6-svscan.html | 38 +++++++++ doc/service/system/goetia-shutdown.html | 133 ++++++++++++++++++++++++++++++++ 2 files changed, 171 insertions(+) create mode 100644 doc/service/system/.s6-svscan.html create mode 100644 doc/service/system/goetia-shutdown.html (limited to 'doc/service') diff --git a/doc/service/system/.s6-svscan.html b/doc/service/system/.s6-svscan.html new file mode 100644 index 0000000..2b1b437 --- /dev/null +++ b/doc/service/system/.s6-svscan.html @@ -0,0 +1,38 @@ + + + + + + + system .s6-svscan + + + +

+ goetia-linux-init +
+ goetia +
+ Software +
+ 0x53.net +

+ +

The system .s6-svscan directory

+ The .s6-svscan directory contains scripts + that are executed if + s6-svscan + receives a signal or exits. + In this case its main use is to properly shutdown + the system using system-shutdown + upon receiving certain signals. +

+ The .s6-svscan directory is easily overlooked, + do not forget to symlink/copy it! +

+ + diff --git a/doc/service/system/goetia-shutdown.html b/doc/service/system/goetia-shutdown.html new file mode 100644 index 0000000..2dd3728 --- /dev/null +++ b/doc/service/system/goetia-shutdown.html @@ -0,0 +1,133 @@ + + + + + + + goetia-shutdown + + + +

+ goetia-linux-init +
+ goetia +
+ Software +
+ 0x53.net +

+ +

The goetia-shutdown service

+ goetia-shutdown is the service that starts + system-shutdown-daemon. + goetia-shutdown is down by default. + Starting it initiates the shutdown procedure. +

+ goetia-shutdown consists of three scripts: +

run

+ This script just executes system-shutdown-daemon. +

stage3b

+ stage3b tries to execute ./stage4, + which is by default not executable. + If it can not execute ./stage4, + and only in this case, + it continues with the following. +
+ It makes ./stage4 executable. +
+ It sends SIGCONT to all processes. +
+ It sleeps for 1 second. +
+ It writes a banner to its standard out. +
+ It send SIGKILL to all processes. +
+ This also stops the system-shutdown-daemon process. + It is automatically restarted by the system supervision tree, + but this time, both the files + ./stage3b and + ./stage4 + are executable. + Which leads to the execution of ./stage4. +

stage4

+ stage4 reads the envdir at the + shutdown-directive subdirectory of the + system runtimedirectory + using + s6-envdir. +
+ It reads the DIRECTIVE evironment variable, + defaulting to -r, if DIRECTIVE is + not specified. +
+ It runs umount -a. +
+ It remounts the root filesystem read-only. +
+ It runs linux-powertool ${DIRECTIVE}. +

Notes

+ The entire shutdown procedure roughly works as follows: +

+ This service, running + system-shutdown-daemon + gets the instructions from + system-shutdown + to shutdown. +
+ system-shutdown-daemon does most of the shutdown procedure. + Part of it is to make stage3b executable. + In the end, system-shutdown-daemon sends SIGTERM to all processes but + PID 1, including itself. +
+ this service gets restarted automatically. + system-shutdown-daemon now instantly executes into stage3b. +
+ stage3b makes stage4 executable. + Followed by sending SIGKILL to all processes + but PID 1, including itself. +
+ The final restart of this service causes + system-shutdown-daemon to instantly execute into + stage3b which instantly executes into stage4, + which instructs the Kernel to do the actual + halt, poweroff or reboot. +

+ + -- cgit v1.2.3