[LTP] [PATCH] close_range: check for kernel support below 5.9

[Edward Liaw]

Check for close_range syscall support in the kernel before running
close_range01 and close_range02 tests.

Signed-off-by: Edward Liaw <edliaw@google.com>
---
 include/lapi/close_range.h                          | 13 +++++++++++++
 .../kernel/syscalls/close_range/close_range01.c     |  2 ++
 .../kernel/syscalls/close_range/close_range02.c     |  1 +
 3 files changed, 16 insertions(+)

diff --git a/include/lapi/close_range.h b/include/lapi/close_range.h
index 19db52d3d..0e464bb30 100644
--- a/include/lapi/close_range.h
+++ b/include/lapi/close_range.h
@@ -25,4 +25,17 @@ static inline int close_range(unsigned int fd, unsigned int max_fd,
 	return tst_syscall(__NR_close_range, fd, max_fd, flags);
 }
 # endif
+
+static inline void close_range_supported_by_kernel(void)
+{
+	long ret;
+
+	if ((tst_kvercmp(5, 9, 0)) < 0) {
+		/* Check if the syscall is backported on an older kernel */
+		ret = syscall(__NR_close_range, 1, 0, 0);
+		if (ret == -1 && errno == ENOSYS)
+			tst_brk(TCONF, "Test not supported on kernel version < v5.9");
+	}
+}
+
 #endif	/* LAPI_CLOSE_RANGE_H__ */
diff --git a/testcases/kernel/syscalls/close_range/close_range01.c b/testcases/kernel/syscalls/close_range/close_range01.c
index 30bb600b6..072bbab66 100644
--- a/testcases/kernel/syscalls/close_range/close_range01.c
+++ b/testcases/kernel/syscalls/close_range/close_range01.c
@@ -53,6 +53,8 @@ static inline void do_close_range(unsigned int fd, unsigned int max_fd,
 
 static void setup(void)
 {
+	close_range_supported_by_kernel();
+
 	struct rlimit nfd;
 
 	SAFE_GETRLIMIT(RLIMIT_NOFILE, &nfd);
diff --git a/testcases/kernel/syscalls/close_range/close_range02.c b/testcases/kernel/syscalls/close_range/close_range02.c
index aec899261..2aa6d2c9f 100644
--- a/testcases/kernel/syscalls/close_range/close_range02.c
+++ b/testcases/kernel/syscalls/close_range/close_range02.c
@@ -111,4 +111,5 @@ static struct tst_test test = {
 	.tcnt = 6,
 	.forks_child = 1,
 	.test = run,
+	.setup = close_range_supported_by_kernel,
 };
-- 
2.39.1.456.gfc5497dd1b-goog