tools/power turbostat: on SIGINT: sample, print and exit

When running in interval-mode, catch interrupts
and print a final data record before exiting.
Signed-off-by: Len Brown <len.brown@intel.com>

tools/power/x86/turbostat/turbostat.8

@@ -267,6 +267,10 @@ CPU	  PRF_CTRL
 
 .fi
 
+.SH SIGNALS
+
+SIGINT will interrupt interval-mode.
+The end-of-interval data will be collected and displayed before turbostat exits.
 .SH NOTES
 
 .B "turbostat "

tools/power/x86/turbostat/turbostat.c

@@ -2600,11 +2600,37 @@ int snapshot_proc_sysfs_files(void)
 	return 0;
 }
 
+int exit_requested;
+
+static void signal_handler (int signal)
+{
+	switch (signal) {
+	case SIGINT:
+		exit_requested = 1;
+		if (debug)
+			fprintf(stderr, " SIGINT\n");
+		break;
+	}
+}
+
+void setup_signal_handler(void)
+{
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof(sa));
+
+	sa.sa_handler = &signal_handler;
+
+	if (sigaction(SIGINT, &sa, NULL) < 0)
+		err(1, "sigaction SIGINT");
+}
 void turbostat_loop()
 {
 	int retval;
 	int restarted = 0;
 
+	setup_signal_handler();
+
 restart:
 	restarted++;
 
@@ -2646,6 +2672,8 @@ void turbostat_loop()
 		compute_average(EVEN_COUNTERS);
 		format_all_counters(EVEN_COUNTERS);
 		flush_output_stdout();
+		if (exit_requested)
+			break;
 		nanosleep(&interval_ts, NULL);
 		if (snapshot_proc_sysfs_files())
 			goto restart;
@@ -2665,6 +2693,8 @@ void turbostat_loop()
 		compute_average(ODD_COUNTERS);
 		format_all_counters(ODD_COUNTERS);
 		flush_output_stdout();
+		if (exit_requested)
+			break;
 	}
 }