Re: [Qemu-devel] [PATCH] qga: Fix shutdown command of guest agent to work with SysV

[whitearchey <whitearchey@gmail.com>]

On Wed, 06 Nov 2013 18:20:36 +0900, Michael Tokarev <mjt@tls.msk.ru> wrote:

> 06.11.2013 05:54, whitearchey wrote:
>> For now guest agent uses following command to shutdown system:
>> shutdown -P +0 "blabla"
>> but this syntax works only with shutdown command from systemd or upstart,
>> because SysV shutdown requires -h switch.
>>
>> Following patch changes the command so it works with systemd, upstart and SysV
>
> While the patch is one-liner indeed, it is a bit more than trivial.
> Because it changes things in a non-obvious way, especially when
> multiple systems are concerned.  Cc'ing qemu-devel@ due to this.
>
>> --- a/qga/commands-posix.c
>> +++ b/qga/commands-posix.c
>> -        execle("/sbin/shutdown", "shutdown", shutdown_flag, "+0",
>> +        execle("/sbin/shutdown", "shutdown", "-h", shutdown_flag, "+0",
>
> Note that shutdown command is not in POSIX, despite the fact
> that this is put into commands-posix.c
>
> Note also that even shutdown from sysvinit on linux has another
> option, -P, which mean poweroff, while -h means "halt OR poweroff"
> (the latter is a bit unclear).
With upstart/systemd qga use one of thee commands, depending on 'mode' parameter:
   shutdown -P +0 "..."
   shutdown -H +0 "..."
   shutdown -r +0 "..."
SysV equivalents for these are:
   shutdown -h -P +0 "..."
   shutdown -h -H +0 "..."
   shutdown -h -r +0 "..."
and these retain their meaning with upstart/systemd.

>
> Does the same work on other *nixes?  *BSD?  Solaris?
>
No, it doesn't. But existing code also does not work.
According to FreeBSD manpages, shutdown does not accept -P and -H options. Commands should be:
   shutdown -p +0 "..."
   shutdown -h +0 "..."
   shutdown -r +0 "..."

shutdown in Solaris does not accept any of -hHpPr and does not accept time in "+0" format

> Thanks,
>
> /mjt