Re: [PATCH v3 2/2] util/log: Always send errors to logfile when daemonized

[Richard Henderson <richard.henderson@linaro.org>]

On 11/9/22 01:00, Greg Kurz wrote:
> When QEMU is started with `-daemonize`, all stdio descriptors get
> redirected to `/dev/null`. This basically means that anything
> printed with error_report() and friends is lost.
> 
> Current logging code allows to redirect to a file with `-D` but
> this requires to enable some logging item with `-d` as well to
> be functional.
> 
> Relax the check on the log flags when QEMU is daemonized, so that
> other users of stderr can benefit from the redirection, without the
> need to enable unwanted debug logs. Previous behaviour is retained
> for the non-daemonized case. The logic is unrolled as an `if` for
> better readability. The qemu_log_level and log_per_thread globals
> reflect the state we want to transition to at this point : use
> them instead of the intermediary locals for correctness.
> 
> qemu_set_log_internal() is adapted to open a per-thread log file
> when '-d tid' is passed. This is done by hijacking qemu_try_lock()
> which seems simpler that refactoring the code.
> 
> Signed-off-by: Greg Kurz<groug@kaod.org>
> ---
>   util/log.c | 72 ++++++++++++++++++++++++++++++++++++++++--------------
>   1 file changed, 53 insertions(+), 19 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~