[Mageia-dev] [soft-commits] [4379] fix shutting down

Thu May 3 12:47:52 CEST 2012

'Twas brillig, and Thomas Backlund at 03/05/12 10:45 did gyre and gimble:
+> Colin Guthrie skrev 3.5.2012 12:33:
+>> 'Twas brillig, and Thierry Vignaud at 03/05/12 09:05 did gyre and gimble:
+>>> On 3 May 2012 09:53, Guillaume Rousse<guillomovitch at gmail.com>  wrote:
+>>>>> please use system("/usr/bin/chvt", "1"), or system(qw(/usr/bin/chvt
+>>>>> 1))
+>>>>> instead in order to not fork useless shells.
+>>>>
+>>>> and kill is a perl builtin perl too:
+>>>> kill SIGRTMAX-10, 1
+>>>
+>>> needs 'use POSIX;' though for symbolic values
+>>
+>> Actually none of the above. Please do it in the systemd unit itself with
+>> ExecStartPre as this actually fixes the issues, whereas the internal
+>> approach does not (at least in my tests) :)
+>>
+> 
+> It seemed to work in vbox, but I'll retest the isos currently building
+
+Ahh OK. I coudln't make it work in my vbox when doing it in the script,
+but if it worked for you then it's probably fine.
+
+>> In actual fact, this shut down script could be something that the
+>> mgalive dracut module drops into /run/systemd/systemd. This would
+>> prevent any poking at the installed file system and maybe allows for
+>> easier hacking - i.e. no need to actually edit the squashfs filesystem
+>> to tweak certain things.
+>>
+> 
+> What/how should this look like ?
+
+Basically the dracut module would add some kind hook that gets run
+during the boot phase that would copy a unit file and a script to the
+/run tree (/run/systemd/system/ folder)
+
+This unit file could be called halt-local.service as this would override
+the one in /lib/systemd/system/ folder of the installed system. The
+dracut hook would also copy the script needed (i.e. the current
+/sbin/halt.local) to somewhere in the run tree (I suggest
+/run/mageia/live-halt or a similarly descriptive name) and the unit
+copied previously would simply refer to it in it's ExecStart= line
+rather than /sbin/halt.local.
+
+I'm still not totally sure how the live CD's are built, but this may
+make tweaking the images more easy than rebuilding the whole squashfs image?
+
+Ping me on IRC if you want to discuss it further or if you want to to
+make a change somewhere - tho' you'll need to point me at where to make
+the change! :)
+
+
+
+As a slightly more radical approach, dracut is also designed to allow a
+pivot back into the initrd on shutdown/reboot.
+
+It does so via these systemd files in the dracut package:
+/lib/systemd/system/dracut-shutdown.service
+/lib/systemd/system/reboot.target.wants/dracut-shutdown.service
+/lib/systemd/system/shutdown.target.wants/dracut-shutdown.service
+
+and this script:
+/usr/lib/dracut/dracut-initramfs-restore
+
+The key systemd file is the first one, the other two are just symlinks
+to ensure it's run when needed.
+
+The script itself is pretty simple and somewhat ugly (also it only
+supports gziped initrds at present - although that should be trivial to
+fix) and relies on naming conventions for initrds as there is no way to
+know which initrd the current boot used AFAIK. I've suggest a workaround
+for both to Harald upstream (short version ship these scripts inside
+initrd and put them in /run too - use the name of the initrd passed on
+dracut command line and you know the compression format used, so you
+also know how to decompress - still not perfect but still a bit better IMO).
+
+Anyway, this allows the initrd continue and there are late hooks we can
+put into our custom dracut module to deal with the whole ejecting stuff.
+Obviously anything needed to do this would have to be included in the
+initramfs (so I don't think the current perl implementation is wise :p)
+
+Anyway, this is more food for thought than practical suggestions at this
+stage - one to think about tho' :)
+
+Col
+
+
+-- 
+
+Colin Guthrie
+colin(at)mageia.org
+http://colin.guthr.ie/
+
+Day Job:
+  Tribalogic Limited http://www.tribalogic.net/
+Open Source:
+  Mageia Contributor http://www.mageia.org/
+  PulseAudio Hacker http://www.pulseaudio.org/
+  Trac Hacker http://trac.edgewall.org/
+