perf tools: Make stat/record print fatal signals of the target program

When a program crashes under perf there is no message about it, unlike
when running it from bash. This can be confusing and lead to wrong
actions during debugging.

Print fatal signals in perf stat/record.

Thanks to Furat Afram for finding the problem originally

Link: http://lkml.kernel.org/r/1316122302-24306-1-git-send-email-andi@firstfloor.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-record.c

@@ -73,6 +73,7 @@ static off_t			post_processing_offset;
 
 static struct perf_session	*session;
 static const char		*cpu_list;
+static const char               *progname;
 
 static void advance_output(size_t size)
 {
@@ -137,18 +138,30 @@ static void mmap_read(struct perf_mmap *md)
 
 static volatile int done = 0;
 static volatile int signr = -1;
+static volatile int child_finished = 0;
 
 static void sig_handler(int sig)
 {
+	if (sig == SIGCHLD)
+		child_finished = 1;
+
 	done = 1;
 	signr = sig;
 }
 
 static void sig_atexit(void)
 {
-	if (child_pid > 0)
+	int status;
+
+	if (child_pid > 0) {
+		if (!child_finished)
 			kill(child_pid, SIGTERM);
 
+		wait(&status);
+		if (WIFSIGNALED(status))
+			psignal(WTERMSIG(status), progname);
+	}
+
 	if (signr == -1 || signr == SIGUSR1)
 		return;
 
@@ -445,6 +458,8 @@ static int __cmd_record(int argc, const char **argv)
 	char buf;
 	struct machine *machine;
 
+	progname = argv[0];
+
 	page_size = sysconf(_SC_PAGE_SIZE);
 
 	atexit(sig_atexit);

tools/perf/builtin-stat.c

@@ -495,6 +495,8 @@ static int run_perf_stat(int argc __used, const char **argv)
 	if (forks) {
 		close(go_pipe[1]);
 		wait(&status);
+		if (WIFSIGNALED(status))
+			psignal(WTERMSIG(status), argv[0]);
 	} else {
 		while(!done) sleep(1);
 	}