[LTP] RFC:[PATCH v1] Added testcase to test mmap with MAP_SHARED_VALIDATE flag

[Paulson Raja L]

This patch adds a new test case for mmap syscall. It tests the
MAP_SHARED_VALIDATE flag of mmap. The code checks of the
MAP_SHARED_VALIDATE flag return EOPNOTSUPP when mapped with an invalid flag
value. It does so by setting the unused bits of the flag argument.

Signed-off-by: Paulson Raja L. <lpaulsonraja@gmail.com>

diff --git a/testcases/kernel/syscalls/mmap/mmap20.c
b/testcases/kernel/syscalls/mmap/mmap20.c
new file mode 100644
index 000000000..2f6dd5d4d
--- /dev/null
+++ b/testcases/kernel/syscalls/mmap/mmap20.c
@@ -0,0 +1,61 @@
+//SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * Test mmap with MAP_SHARED_VALIDATE flag
+ *
+ * We are testing the MAP_SHARED_VALIDATE flag of mmap() syscall. To check
+ * if there is an invalid flag value, the MAP_SHARED_VALIDATE return
+ * EOPNOTSUPP. The unused bit in the MAP_SHARED_VALIDATE is found, and by
+ * setting the unused bits of the flag argument the flag value becomes
+ * invalid and the error EOPNOTSUPP is produced as expected.
+ */
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <linux/mman.h>
+#include <errno.h>
+#include "tst_test.h"
+
+#define TEST_FILE "file_to_mmap"
+#define TEST_FILE_SIZE 1024
+#define TEST_FILE_MODE 0600
+
+static int fd_file;
+static void *mapped_address = NULL;
+
+static void setup(void)
+{
+ fd_file = SAFE_OPEN(TEST_FILE, O_CREAT | O_RDWR, TEST_FILE_MODE);
+ if (tst_fill_file(TEST_FILE, 'a', TEST_FILE_SIZE, 1))
+ tst_brk(TBROK, "Could not fill the testfile.");
+}
+
+static void cleanup(void)
+{
+ if (fd_file > 0)
+ SAFE_CLOSE(fd_file);
+ if (mapped_address != NULL && mapped_address != MAP_FAILED)
+ SAFE_MUNMAP(mapped_address, TEST_FILE_SIZE);
+}
+
+static void test_mmap(void)
+{
+ mapped_address = mmap(NULL, TEST_FILE_SIZE, PROT_READ | PROT_WRITE,
+      (1 << 7) | (1 << 9) | MAP_SHARED_VALIDATE, fd_file, 0);
+ if (mapped_address != MAP_FAILED)
+ tst_res(TFAIL | TERRNO, "mmap() is successful, but it should have
failed.");
+ else if (errno == EOPNOTSUPP)
+ tst_res(TPASS, "mmap() failed with errno set to EOPNOTSUPP.");
+ else
+ tst_res(TFAIL | TERRNO, "mmap() failed with unexpected error.");
+}
+
+static struct tst_test test = {
+ .min_kver = "4.15",
+ .setup = setup,
+ .cleanup = cleanup,
+ .test_all = test_mmap,
+ .needs_tmpdir = 1,
+};