On 11/02/2016 13:12, Dimitris Aragiorgis wrote:
> Besides that, when one executes a daemon, shell redirection is
> hardly, if ever, used. More so if the daemon already has a logfile
> option.
>
> So, we decided to give it a go and find the least painful way to
> log the stderr of a QEMU process to a logfile.
>
> To our understanding, the logfile (-D option) is used only for
> messages generated by qemu_log()/qemu_log_mask(). The current
> situation however is that fprintf(stderr, ...) is used in various
> places throughout the codebase for logging/debug purposes.
Right, mostly through error_report.
Actually I like your approach (log to -D if daemonize is used). I
just was not sure of the best way to implement it.
Perhaps when the logfile is opened you can replace the straight fopen with
qemu_logfile = fopen(...);
if (daemonized) {
dup2(fileno(qemu_logfile), STDERR_FILENO);
fclose(qemu_logfile);
qemu_logfile = stderr;
}
Then the logfile will never be closed by qemu_log_close, and stderr
will always be sent to it. Does this look sane?
Paolo
