[LTP] [PATCH] Add test case to cover the setting resource limit64 for process

[chunfuwen]

The test ensures that the process gets the correct signals in the correct order:

First, it should get SIGXCPU after reaching the soft CPU time limit64.
Then, if the CPU time exceeds the hard limit, it should receive SIGKILL

Signed-off-by: chunfuwen <chwen@redhat.com>
---
 .../kernel/syscalls/setrlimit/setrlimit07.c   | 129 ++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 testcases/kernel/syscalls/setrlimit/setrlimit07.c

diff --git a/testcases/kernel/syscalls/setrlimit/setrlimit07.c b/testcases/kernel/syscalls/setrlimit/setrlimit07.c
new file mode 100644
index 000000000..031d58c64
--- /dev/null
+++ b/testcases/kernel/syscalls/setrlimit/setrlimit07.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017 Red Hat Inc. All Rights Reserved.
+ * Author: Chunfu Wen <chwen@redhat.com>
+ */
+
+/*
+ * Description:
+ * Set CPU time limit64 for a process and check its behavior
+ * after reaching CPU time limit64.
+ * 1) Process got SIGXCPU after reaching soft limit of CPU time limit64.
+ * 2) Process got SIGKILL after reaching hard limit of CPU time limit64.
+ *
+ */
+
+#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 <stdlib.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <inttypes.h>
+
+#include "tst_test.h"
+
+#include "lapi/syscalls.h"
+#include "lapi/abisize.h"
+
+#ifndef HAVE_STRUCT_RLIMIT64
+struct rlimit64 {
+	uint64_t rlim_cur;
+	uint64_t rlim_max;
+};
+#endif
+
+static int *end;
+
+static void sighandler(int sig)
+{
+	*end = sig;
+}
+
+static void setup(void)
+{
+	SAFE_SIGNAL(SIGXCPU, sighandler);
+
+	end = SAFE_MMAP(NULL, sizeof(int), PROT_READ | PROT_WRITE,
+			MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+}
+
+static void cleanup(void)
+{
+	if (end)
+		SAFE_MUNMAP(end, sizeof(int));
+}
+
+static int setrlimit_u64(int resource, const struct rlimit64 *rlim)
+{
+    return tst_syscall(__NR_prlimit64, 0, resource, rlim, NULL);
+}
+
+static void verify_setrlimit64(void)
+{
+	int status;
+	pid_t pid;
+	struct rlimit64 rlim;
+	rlim.rlim_cur = 1;
+	rlim.rlim_max = 2;
+
+	*end = 0;
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		TEST(setrlimit_u64(RLIMIT_CPU, &rlim));
+		if (TST_RET == -1) {
+			tst_res(TFAIL | TTERRNO,
+				"setrlimit_u64(RLIMIT_CPU) failed");
+			exit(1);
+		}
+
+		alarm(20);
+
+		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,
+				"Got SIGXCPU then SIGKILL after reaching both limit");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGKILL && !*end) {
+			tst_res(TFAIL,
+				"Got only SIGKILL after reaching both limit");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGALRM && *end == SIGXCPU) {
+			tst_res(TFAIL,
+				"Got only SIGXCPU after reaching both limit");
+			return;
+		}
+
+		if (WTERMSIG(status) == SIGALRM && !*end) {
+			tst_res(TFAIL,
+				"Got no signal after reaching both limit");
+			return;
+		}
+	}
+
+	tst_res(TFAIL, "Child %s", tst_strstatus(status));
+}
+
+static struct tst_test test = {
+	.test_all = verify_setrlimit64,
+	.setup = setup,
+	.cleanup = cleanup,
+	.forks_child = 1,
+};
-- 
2.43.5