[PATCH i-g-t v2] runner/executor: Detect when child process is killed by a signal

[Peter Senna Tschudin <peter.senna@linux.intel.com>]

Make igt-runner aware about tests being killed by signals. Before this
patch, manually killing a test process would result in igt-runner silently
marking the test as incomplete.

Now igt-runner aborts the run verbosely. As an example the following was
extracted from results.json:
 This test caused an abort condition: Test terminated by a signal -9

v2: fix race condition

Cc: Petri Latvala <adrinael@adrinael.net>
Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@intel.com>
---
 runner/executor.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/runner/executor.c b/runner/executor.c
index ac73e1dde..5f653b0d4 100644
--- a/runner/executor.c
+++ b/runner/executor.c
@@ -888,6 +888,7 @@ static int monitor_output(pid_t child,
 	const int interval_length = 1;
 	int wd_timeout;
 	int killed = 0; /* 0 if not killed, signal number otherwise */
+	bool child_reaped = false;
 	struct timespec time_beg, time_now, time_last_activity, time_last_subtest, time_killed;
 	unsigned long taints = 0;
 	bool aborting = false;
@@ -960,6 +961,24 @@ static int monitor_output(pid_t child,
 
 		igt_gettime(&time_now);
 
+		if (child == waitpid(child, &status, WNOHANG))
+			child_reaped = true;
+
+		if (child_reaped) {
+			if(WIFSIGNALED(status)) {
+				/* The test terminated by a signal */
+
+				aborting = true;
+				killed = -WTERMSIG(status);
+
+				sprintf(buf, "Test terminated by a signal %d\n", killed);
+				errf("%s", buf);
+				*abortreason = strdup(buf);
+
+				break;
+			}
+		}
+
 		/* TODO: Refactor these handlers to their own functions */
 		if (outfd >= 0 && FD_ISSET(outfd, &set)) {
 			char *newline;
@@ -1241,7 +1260,11 @@ static int monitor_output(pid_t child,
 				errf("Error reading from signalfd: %m\n");
 				continue;
 			} else if (siginfo.ssi_signo == SIGCHLD) {
-				if (child != waitpid(child, &status, WNOHANG)) {
+				if (!child_reaped) {
+					if (child == waitpid(child, &status, WNOHANG))
+						child_reaped = true;
+				}
+				if (!child_reaped) {
 					errf("Failed to reap child\n");
 					status = 9999;
 				} else if (WIFEXITED(status)) {
-- 
2.34.1