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

From: Zhangjin Wu
Date: Wed Jun 28 2023 - 09:53:02 EST


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@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/bff82ea6-610b-4471-a28b-6c76c28604a6@xxxxxxxx/
Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx>
---
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