[libvirt] [PATCH] lxc: Fix reboot via initctl
Daniel P. Berrangé
berrange at redhat.com
Thu Jul 4 09:31:16 UTC 2019
On Thu, Jul 04, 2019 at 11:04:15AM +0200, Lubomir Rintel wrote:
> virInitctlSetRunLevel() returns 0 only if ended up doing nothing, 1 if it
> actually succeeded. Let's check for the error condition.
>
> Without this, a successful reboot would be treated as a failure and the
> LXC driver will proceed sending a TERM signal instead, effectively
> cancelling the shutdown.
Can you elaborate on this a bit as I'm not seeing a way for this to
happen with the current code.
- virInitctlSetRunLevel returns 0 if no init was found, 1 if it
was successful, -1 on error
- lxcDomainInitctlCallback checks whether init exists and is
not the same as the host init a then calls virInitctlSetRunLevel.
Due to the checks virInitctlSetRunLevel can only ever return
1 or -1 in this scenario. 0 will never happen
- virLXCDomainSetRunlevel calls lxcDomainInitctlCallback via
virProcessRunInMountNamespace and honours the return status.
So virLXCDomainSetRunlevel shoudl return -1 on error, 1 on
success
- lxcDomainShutdownFlags calls virLXCDomainSetRunlevel and
saves its return value to a variable 'rc'
- If 'rc' is -1 then it sends SIGTERM, otherwise it just
returns 0 indicating success
So I'm not following how we can end up successing talking to
init, and then also sending SIGTERM.
In fact there is a different problem here I believe. We should
be sending SIGTERM when 'rc' is 0 not -1, because rc==0 is what
indicates no init was present.
>
> Signed-off-by: Lubomir Rintel <lkundrak at v3.sk>
> ---
> src/lxc/lxc_domain.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/src/lxc/lxc_domain.c b/src/lxc/lxc_domain.c
> index 51a9fd36eb..1dc2d0d4cf 100644
> --- a/src/lxc/lxc_domain.c
> +++ b/src/lxc/lxc_domain.c
> @@ -457,7 +457,9 @@ lxcDomainInitctlCallback(pid_t pid ATTRIBUTE_UNUSED,
> data->st[i].st_ino == cont_sb.st_ino)
> continue;
>
> - return virInitctlSetRunLevel(fifo, data->runlevel);
> + if (virInitctlSetRunLevel(fifo, data->runlevel) == -1)
> + return -1;
> + return 0;
> }
>
> /* If no usable fifo was found then declare success. Caller
> --
> 2.21.0
>
> --
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Regards,
Daniel
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