perf_counter tools: Propagate signals properly

Currently report and stat catch SIGINT (and others) without altering
their exit state. This means that things like:

   while :; do perf stat ./foo ; done

Loops become hard-to-interrupt, because bash never sees perf terminate
due to interruption. Fix this.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index a5698ad..c10553c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -169,10 +169,21 @@
 }
 
 static volatile int done = 0;
+static volatile int signr = -1;
 
 static void sig_handler(int sig)
 {
 	done = 1;
+	signr = sig;
+}
+
+static void sig_atexit(void)
+{
+	if (signr == -1)
+		return;
+
+	signal(signr, SIG_DFL);
+	kill(getpid(), signr);
 }
 
 static void pid_synthesize_comm_event(pid_t pid, int full)
@@ -459,6 +470,7 @@
 	} else for (i = 0; i < nr_cpus; i++)
 		open_counters(i, target_pid);
 
+	atexit(sig_atexit);
 	signal(SIGCHLD, sig_handler);
 	signal(SIGINT, sig_handler);