[PATCH] proc: smoke test lseek()

From: Alexey Dobriyan
Date: Wed Apr 07 2021 - 15:55:23 EST


Now that ->proc_lseek has been made mandatory it would be nice to test
that nothing has been forgotten.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

May want to fold into
proc-mandate-proc_lseek-in-struct-proc_ops.patch

tools/testing/selftests/proc/read.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/proc/read.c
+++ b/tools/testing/selftests/proc/read.c
@@ -14,7 +14,7 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
// Test
-// 1) read of every file in /proc
+// 1) read and lseek on every file in /proc
// 2) readlink of every symlink in /proc
// 3) recursively (1) + (2) for every directory in /proc
// 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs
@@ -45,6 +45,8 @@ static void f_reg(DIR *d, const char *filename)
fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
if (fd == -1)
return;
+ /* struct proc_ops::proc_lseek is mandatory if file is seekable. */
+ (void)lseek(fd, 0, SEEK_SET);
rv = read(fd, buf, sizeof(buf));
assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
close(fd);