[PATCH] make strace handle SIGTRAP properly

[Dmitry V. Levin]

On Thu, May 26, 2011 at 10:55:14AM +0200, Denys Vlasenko wrote:
[...]
> Please take a look at the patch below. It should have all your
> suggestions incorporated.

Thanks, OK for me, with one more suggestion related to *error_msg*()
implementation.

> -static void error_msg_and_die(const char *fmt, ...)
> -#if defined __GNUC__
> -	__attribute__ ((noreturn, format(printf, 1, 2)))
> -#endif
> -;
> -static void error_msg_and_die(const char *fmt, ...)
> +static void verror_msg(int err_and_exitflag, const char *fmt, va_list p)
>  {
>  	char *msg;
> -	va_list p;
>  
> -	va_start(p, fmt);
>  	msg = NULL;
>  	vasprintf(&msg, fmt, p);
>  	if (msg) {
> -		fprintf(stderr, "%s: %s\n", progname, msg);
> +		int err = err_and_exitflag & INT_MAX;
> +		fflush(NULL);
> +		if (err)
> +			fprintf(stderr, "%s: %s: %s\n", progname, msg, strerror(err));
> +		else
> +			fprintf(stderr, "%s: %s\n", progname, msg);
>  		free(msg);
>  	}
> +
> +	if (err_and_exitflag & ((unsigned)INT_MAX+1)) {
> +		/* Careful: don't do cleanup not from tracer process */
> +		if (strace_tracer_pid == getpid()) {
> +			/* TODO? cflag = 0; -- or else cleanup() may print summary */
> +			cleanup();
> +		}
> +		exit(1);
> +	}
> +}

I think it would be more readable just to create a simple die() function
instead:

static void die(void) __attribute__ ((noreturn))
{
	if (strace_tracer_pid == getpid()) {
		cflag = 0;
		cleanup();
	}
	exit(1);
}

> +void error_msg_and_die(const char *fmt, ...)
> +{
> +	va_list p;
> +	va_start(p, fmt);
> +	verror_msg(((unsigned)INT_MAX+1), fmt, p);
> +	exit(1); /* verror_msg won't return. shut up compiler's warning */

verror_msg(0, fmt, p);
die();

> +}
> +
> +void perror_msg(const char *fmt, ...)
> +{
> +	va_list p;
> +	va_start(p, fmt);
> +	verror_msg(errno, fmt, p);
> +	va_end(p);
> +}
> +
> +void perror_msg_and_die(const char *fmt, ...)
> +{
> +	va_list p;
> +	va_start(p, fmt);
> +	verror_msg(((unsigned)INT_MAX+1) | errno, fmt, p);
> +	exit(1); /* verror_msg won't return. shut up compiler's warning */

verror_msg(errno, fmt, p);
die();


-- 
ldv
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