[libvirt] [PATCH] admin: Throw a system error when 'open' fails on user-provided output

[Jiri Denemark]

On Fri, Mar 31, 2017 at 10:29:25 +0200, Erik Skultety wrote:
> There was an unhandled 'open' call which resulted in:
> 
> "error: Library function returned error but did not set virError"
> 
> Even if this happens during the daemon's start when we still don't have
> any set of outputs defined yet, we can safely report an error, since we
> automatically fallback to stderr which is fine even for both
> running as a daemonized process, since this happens before the daemon
> forks into the background, and running as a systemd service, since
> systemd re-directs std outputs to journald by default.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1436060
> 
> Signed-off-by: Erik Skultety <eskultet at redhat.com>
> ---
>  src/util/virlog.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/src/util/virlog.c b/src/util/virlog.c
> index 7b584f8e37..7933e1a7a0 100644
> --- a/src/util/virlog.c
> +++ b/src/util/virlog.c
> @@ -750,8 +750,10 @@ virLogNewOutputToFile(virLogPriority priority,
>      virLogOutputPtr ret = NULL;
>  
>      fd = open(file, O_CREAT | O_APPEND | O_WRONLY, S_IRUSR | S_IWUSR);
> -    if (fd < 0)
> +    if (fd < 0) {
> +        virReportSystemError(errno, _("failed to open %s"), file);
>          return NULL;
> +    }
>  
>      if (!(ret = virLogOutputNew(virLogOutputToFd, virLogCloseFd,
>                                  (void *)(intptr_t)fd,

ACK and safe for freeze.

Jirka