Re: [nft PATCH v3] configure: Implement --enable-profiling option

[Florian Westphal <fw@strlen.de>]

Phil Sutter <phil@nwl.cc> wrote:
> This will set compiler flag --coverage so code coverage may be inspected
> using gcov.
> 
> In order to successfully profile processes which are killed or
> interrupted as well, add a signal handler for those cases which calls
> exit(). This is relevant for test cases invoking nft monitor.
>
> index 0000000000000..912ead9d7eb94
> --- /dev/null
> +++ b/src/profiling.c
> @@ -0,0 +1,36 @@
> +/*
> + * Copyright (c) Red Hat GmbH.  Author: Phil Sutter <phil@nwl.cc>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 (or any
> + * later) as published by the Free Software Foundation.
> + */
> +
> +#include <nft.h>
> +#include <profiling.h>
> +
> +#include <signal.h>
> +#include <stdio.h>
> +
> +static void termhandler(int signo)
> +{
> +	switch (signo) {
> +	case SIGTERM:
> +		exit(143);
> +	case SIGINT:
> +		exit(130);

Unfortunately I can't find exit(3) in the list of async-signal safe
functions, so I have to assume this isn't allowed.

From a quick glance, I would suggest to either use self-pipe-trick, or,
given nft is linux specific anyway, use signalfd(2) instead of a
traditional handler; then, stuff the fd into mnl_nft_event_listener
select().

Sorry, I did not think of this earlier.  If I'm wrong and this is safe,