[PATCH v5 14/14] selftests/nolibc: add mmap and munmap test cases

[Zhangjin Wu]

Three mmap/munmap related test cases are added:

- mmap_bad: the length argument must be greater than 0, otherwise, fail
  with -EINVAL.

- munmap_bad: invalid (void *)-1 address fail with -EINVAL.

- mmap_munmap_good: mmap() a file with good offset and then munmap().

Note, it is not easy to find a unique file for mmap() in different
scenes, so, a file list is used to search the right one:

- /proc/1/exe, for 'run' and 'run-user' target
  'run-user' can not find '/proc/self/exe'

- /proc/self/exe, for 'libc-test' target
  normal program 'libc-test' has no permission to access '/proc/1/exe'

- the others, for kernel without procfs
  let it pass even with 'worst case' kernel configs

Suggested-by: Thomas Weißschuh <linux at weissschuh.net>
Link: https://lore.kernel.org/lkml/bff82ea6-610b-4471-a28b-6c76c28604a6@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon at tinylab.org>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 56 ++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 80ab29e2887c..b178bfa29ad9 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -592,6 +592,59 @@ static int test_stat_timestamps(void)
 	return 0;
 }
 
+int test_mmap_munmap(void)
+{
+	int ret, fd, i;
+	void *mem;
+	size_t page_size, file_size, length;
+	off_t offset, pa_offset;
+	struct stat stat_buf;
+	static const char * const files[] = {
+		"/proc/1/exe", "/proc/self/exe",
+		"/init", "/sbin/init", "/etc/init", "/bin/init", "/bin/sh",
+		NULL
+	};
+
+	page_size = getpagesize();
+	if (page_size < 0)
+		return -1;
+
+	/* find a right file to mmap, existed and accessible */
+	for (i = 0; files[i] != NULL; i++) {
+		ret = fd = open(files[i], O_RDONLY);
+		if (ret == -1)
+			continue;
+		else
+			break;
+	}
+	if (ret == -1)
+		return ret;
+
+	ret = stat(files[i], &stat_buf);
+	if (ret == -1)
+		goto end;
+
+	file_size = stat_buf.st_size;
+	offset = file_size - 1;
+	if (offset < 0)
+		offset = 0;
+	length = file_size - offset;
+	pa_offset = offset & ~(page_size - 1);
+
+	mem = mmap(NULL, length + offset - pa_offset, PROT_READ, MAP_SHARED, fd, pa_offset);
+	if (mem == MAP_FAILED) {
+		ret = -1;
+		goto end;
+	}
+
+	ret = munmap(mem, length + offset - pa_offset);
+
+end:
+	close(fd);
+	return ret;
+}
+
+
 /* Run syscall tests between IDs <min> and <max>.
  * Return 0 on success, non-zero on failure.
  */
@@ -666,6 +719,9 @@ int run_syscall(int min, int max)
 		CASE_TEST(lseek_m1);          EXPECT_SYSER(1, lseek(-1, 0, SEEK_SET), -1, EBADF); break;
 		CASE_TEST(lseek_0);           EXPECT_SYSER(1, lseek(0, 0, SEEK_SET), -1, ESPIPE); break;
 		CASE_TEST(mkdir_root);        EXPECT_SYSER(1, mkdir("/", 0755), -1, EEXIST); break;
+		CASE_TEST(mmap_bad);          EXPECT_PTRER(1, mmap(NULL, 0, PROT_READ, MAP_PRIVATE, 0, 0), MAP_FAILED, EINVAL); break;
+		CASE_TEST(munmap_bad);        EXPECT_SYSER(1, munmap((void *)-1, 0), -1, EINVAL); break;
+		CASE_TEST(mmap_munmap_good);  EXPECT_SYSZR(1, test_mmap_munmap()); break;
 		CASE_TEST(open_tty);          EXPECT_SYSNE(1, tmp = open("/dev/null", 0), -1); if (tmp != -1) close(tmp); break;
 		CASE_TEST(open_blah);         EXPECT_SYSER(1, tmp = open("/proc/self/blah", 0), -1, ENOENT); if (tmp != -1) close(tmp); break;
 		CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
-- 
2.25.1