@@ -595,6 +595,65 @@ 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;
+ const char * const files[] = {
+ "/dev/zero",
+ "/proc/1/exe", "/proc/self/exe",
+ argv0,
+ 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 of the special /dev/zero is 0, let's assign one manually */
+ if (i == 0)
+ file_size = 3*page_size;
+ else
+ 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.
*/
@@ -671,6 +730,7 @@ int run_syscall(int min, int max)
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;
mmap() a file with a good offset and then munmap() it. a non-zero offset is passed to test the 6th argument of my_syscall6(). 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: - /dev/zero: is commonly used to allocate anonymous memory and is likely present and readable - /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' - argv0: the path of the program itself, let it pass even with worst case scene: no procfs and no /dev/zero Suggested-by: Willy Tarreau <w@1wt.eu> Link: https://lore.kernel.org/lkml/20230702193306.GK16233@1wt.eu/ Suggested-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/lkml/bff82ea6-610b-4471-a28b-6c76c28604a6@t-8ch.de/ Signed-off-by: Zhangjin Wu <falcon@tinylab.org> --- tools/testing/selftests/nolibc/nolibc-test.c | 60 ++++++++++++++++++++ 1 file changed, 60 insertions(+)