From d6aefcd1538d2369be506b7a042109945c9b6dab Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 17 Apr 2014 08:32:22 -0400
Subject: [PATCH] test_urcu_fork: test many fork, with 3 children deep

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 tests/regression/test_urcu_fork.c | 88 ++++++++++++++++++++++---------
 1 file changed, 63 insertions(+), 25 deletions(-)

diff --git a/tests/regression/test_urcu_fork.c b/tests/regression/test_urcu_fork.c
index ce0c9ca..06786b0 100644
--- a/tests/regression/test_urcu_fork.c
+++ b/tests/regression/test_urcu_fork.c
@@ -44,6 +44,13 @@
 #endif
 #include <urcu.h>
 
+/* We generate children 3 levels deep */
+#define FORK_DEPTH	3
+/* Each generation spawns 10 children */
+#define NR_FORK		10
+
+static int fork_generation;
+
 struct test_node {
 	int somedata;
 	struct rcu_head head;
@@ -80,68 +87,99 @@ static void test_rcu(void)
 	rcu_unregister_thread();
 }
 
-int main(int argc, char **argv)
+/*
+ * Return 0 if child, > 0 if parent, < 0 on error.
+ */
+static int do_fork(const char *execname)
 {
 	pid_t pid;
-	int ret;
-
-#if 0
-	/* pthread_atfork does not work with malloc/free in callbacks */
-	ret = pthread_atfork(call_rcu_before_fork,
-		call_rcu_after_fork_parent,
-		call_rcu_after_fork_child);
-	if (ret) {
-		errno = ret;
-		perror("pthread_atfork");
-		exit(EXIT_FAILURE);
-	}
-#endif
-
-	test_rcu();
-
-	synchronize_rcu();
 
 	fprintf(stderr, "%s parent pid: %d, before fork\n",
-		argv[0], (int) getpid());
+		execname, (int) getpid());
 
 	call_rcu_before_fork();
 	pid = fork();
-
 	if (pid == 0) {
 		/* child */
+		fork_generation++;
+
 		call_rcu_after_fork_child();
 		fprintf(stderr, "%s child pid: %d, after fork\n",
-			argv[0], (int) getpid());
+			execname, (int) getpid());
 		test_rcu();
 		fprintf(stderr, "%s child pid: %d, after rcu test\n",
-			argv[0], (int) getpid());
+			execname, (int) getpid());
+		if (fork_generation >= FORK_DEPTH)
+			exit(EXIT_SUCCESS);
+		return 0;
 	} else if (pid > 0) {
 		int status;
 
 		/* parent */
 		call_rcu_after_fork_parent();
 		fprintf(stderr, "%s parent pid: %d, after fork\n",
-			argv[0], (int) getpid());
+			execname, (int) getpid());
 		test_rcu();
 		fprintf(stderr, "%s parent pid: %d, after rcu test\n",
-			argv[0], (int) getpid());
+			execname, (int) getpid());
 		for (;;) {
 			pid = wait(&status);
+			if (pid < 0) {
+				perror("wait");
+				return -1;
+			}
 			if (WIFEXITED(status)) {
 				fprintf(stderr, "child %u exited normally with status %u\n",
 					pid, WEXITSTATUS(status));
+				if (WEXITSTATUS(status))
+					return -1;
 				break;
 			} else if (WIFSIGNALED(status)) {
 				fprintf(stderr, "child %u was terminated by signal %u\n",
 					pid, WTERMSIG(status));
-				break;
+				return -1;
 			} else {
 				continue;
 			}
 		}
+		return 1;
 	} else {
 		perror("fork");
+		return -1;
+	}
+}
+
+int main(int argc, char **argv)
+{
+	unsigned int i;
+
+#if 0
+	/* pthread_atfork does not work with malloc/free in callbacks */
+	ret = pthread_atfork(call_rcu_before_fork,
+		call_rcu_after_fork_parent,
+		call_rcu_after_fork_child);
+	if (ret) {
+		errno = ret;
+		perror("pthread_atfork");
 		exit(EXIT_FAILURE);
 	}
+#endif
+
+restart:
+	for (i = 0; i < NR_FORK; i++) {
+		int ret;
+
+		test_rcu();
+		synchronize_rcu();
+		ret = do_fork(argv[0]);
+		if (ret == 0)		/* child */
+			goto restart;
+		else if (ret < 0)
+			goto error;
+		/* else parent, continue. */
+	}
 	exit(EXIT_SUCCESS);
+
+error:
+	exit(EXIT_FAILURE);
 }
-- 
2.34.1