Re: [Qemu-devel] [RFC PATCH] qemu-log: Open file for logging when specified

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/06/2015 16:20, Pranith Kumar wrote:
> qemu-log defaults to stderr when there is no '-D' option mentioned on command
> line. When '-D' option is specified, we also need to specify '-d' option for it
> to use the specified logfile. When using monitor to enable logging this is
> troublesome since there will be no '-d' option because of which monitor dumps
> the logs to stderr.
> 
> Fix this by opening the log file when '-D' is specified on the command line.
> Also fix an ancient comment which does not hold true since changing location and
> log level has now been streamlined.
> 
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Luiz Capitulino <lcapitulino@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Peter Maydell <peter.maydell@linaro.org>
> ---
>  vl.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/vl.c b/vl.c
> index d4b2d03..5f81ccc 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3845,17 +3845,14 @@ int main(int argc, char **argv, char **envp)
>          exit(0);
>      }
>  
> -    /* Open the logfile at this point, if necessary. We can't open the logfile
> -     * when encountering either of the logging options (-d or -D) because the
> -     * other one may be encountered later on the command line, changing the
> -     * location or level of logging.
> +    /* Open the logfile at this point and set the log mask if necessary.
>       */
> +    if (log_file) {
> +        qemu_set_log_filename(log_file);
> +    }
> +
>      if (log_mask) {
>          int mask;
> -        if (log_file) {
> -            qemu_set_log_filename(log_file);
> -        }
> -
>          mask = qemu_str_to_log_mask(log_mask);
>          if (!mask) {
>              qemu_print_log_usage(stdout);
> 

Good idea---also it is consistent with what user-mode emulation already
does.

Paolo