Re: [Qemu-devel] [PATCH 3/9] log: improve code in do_qemu_set_log

[Paolo Bonzini <pbonzini@redhat.com>]

On 14/03/2016 12:21, Denis V. Lunev wrote:
>          /* In case -D is given do not redirect stderr to /dev/null */
> -        if (!qemu_logfile) {
> +        if (!qemu_logfile || qemu_logfile == stderr) {
>              dup2(fd, 2);

This relies on knowledge that fileno(qemu_logfile) is dup-ed to stderr.
 I'm not sure what's the problem in commit c586eac33; the idea is that,
if -daemonize is given, a named logfile should always be open (so that
stderr is redirected) but stderr should not be used as log destination
(because that's just /dev/null).  That's clear from the condition:

   is_daemonized() ? logfilename != NULL : qemu_loglevel

Paolo