[LTP] [PATCH] syscalls/setrlimit06: Add new test for RLIMIT_CPU

[Xiao Yang]

Set CPU time limit for a process and check its behavior when
reaching CPU time limit.

Note:
This is also a regression test for commit c3bca5d450b62 in kernel:
"posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated"

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
---
 runtest/syscalls                                  |   1 +
 testcases/kernel/syscalls/setrlimit/.gitignore    |   1 +
 testcases/kernel/syscalls/setrlimit/setrlimit06.c | 108 ++++++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 testcases/kernel/syscalls/setrlimit/setrlimit06.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 668c87c..2e36709 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1197,6 +1197,7 @@ setrlimit02 setrlimit02
 setrlimit03 setrlimit03
 setrlimit04 setrlimit04
 setrlimit05 setrlimit05
+setrlimit06 setrlimit06
 
 set_robust_list01 set_robust_list01
 set_thread_area01 set_thread_area01
diff --git a/testcases/kernel/syscalls/setrlimit/.gitignore b/testcases/kernel/syscalls/setrlimit/.gitignore
index e91f7e8..a790eb9 100644
--- a/testcases/kernel/syscalls/setrlimit/.gitignore
+++ b/testcases/kernel/syscalls/setrlimit/.gitignore
@@ -3,3 +3,4 @@
 /setrlimit03
 /setrlimit04
 /setrlimit05
+/setrlimit06
diff --git a/testcases/kernel/syscalls/setrlimit/setrlimit06.c b/testcases/kernel/syscalls/setrlimit/setrlimit06.c
new file mode 100644
index 0000000..d6004a5
--- /dev/null
+++ b/testcases/kernel/syscalls/setrlimit/setrlimit06.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
+ * Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
+ */
+
+/*
+ * Description:
+ * Set CPU time limit for a process and check its behavior
+ * when reaching CPU time limit.
+ * 1) Process received SIGXCPU signal when reaching soft limit
+ *    of CPU time.
+ * 2) Process received SIGKILL signal when reaching hard limit
+ *    of CPU time.
+ *
+ * Note:
+ * This is also a regression test for the following kernel bug:
+ * 'c3bca5d450b62 ("posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated")'
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/wait.h>
+
+#include "tst_test.h"
+
+static volatile int end;
+
+static void sighandler(int sig)
+{
+	end = sig;
+}
+
+static void setup(void)
+{
+	SAFE_SIGNAL(SIGALRM, SIG_DFL);
+	SAFE_SIGNAL(SIGXCPU, sighandler);
+}
+
+static void verify_setrlimit(void)
+{
+	int status;
+	pid_t pid;
+
+	pid = vfork();
+	if (pid == -1)
+		tst_brk(TBROK, "vfork() failed");
+
+	if (!pid) {
+		struct rlimit rlim = {
+			.rlim_cur = 2,
+			.rlim_max = 3,
+		};
+
+		TEST(setrlimit(RLIMIT_CPU, &rlim));
+		if (TST_RET == -1) {
+			tst_res(TFAIL | TTERRNO,
+				"setrlimit(RLIMIT_CPU) failed");
+			_exit(1);
+		}
+
+		alarm(10);
+
+		while (1);
+	}
+
+	SAFE_WAITPID(pid, &status, 0);
+
+	if (WIFEXITED(status) && WEXITSTATUS(status) == 1)
+		return;
+
+	if (WIFSIGNALED(status)) {
+		if (WTERMSIG(status) == SIGKILL && end == SIGXCPU) {
+			tst_res(TPASS,
+				"Process received SIGXCPU and SIGKILL when reaching soft and hard limit of CPU time");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGKILL && !end) {
+			tst_res(TFAIL,
+				"Process only received SIGKILL when reaching CPU time hard limit");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGALRM && end == SIGXCPU) {
+			tst_res(TFAIL,
+				"Process only received SIGXCPU when reaching CPU time soft limit");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGALRM && !end) {
+			tst_res(TFAIL,
+				"Process didn't receive any signal when reaching soft and hard limit of CPU time");
+			return;
+		}
+	}
+
+	tst_res(TBROK, "child %s", tst_strstatus(status));
+}
+
+static struct tst_test test = {
+	.test_all = verify_setrlimit,
+	.setup = setup,
+};
-- 
1.8.3.1