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.

Signed-off-by: Lubomir Rintel <lkundrak@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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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@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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