[PATCH] selftests/ipc: Use IPC_STAT to get queue information

[Muhammed Sariyildiz <asiyee994@gmail.com>]

dump_queue() finds the message queue's stats by brute-forcing kernel
indexes 0..255 with MSG_STAT and comparing the returned identifier with
msgque->msq_id. This misses queues whose index is 256 or larger, and if
no match is found the loop ends and the code goes on using a stale
or uninitialized struct msqid_ds.

The identifier is already known, so query it directly with IPC_STAT.
This removes the loop and reports a failure if the queue cannot be
queried.

Signed-off-by: Muhammed Sariyildiz <asiyee994@gmail.com>
---
 tools/testing/selftests/ipc/msgque.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/ipc/msgque.c b/tools/testing/selftests/ipc/msgque.c
index 4b4c1ab..f4168c7 100644
--- a/tools/testing/selftests/ipc/msgque.c
+++ b/tools/testing/selftests/ipc/msgque.c
@@ -130,21 +130,13 @@ err:
 int dump_queue(struct msgque_data *msgque)
 {
 	struct msqid_ds ds;
-	int kern_id;
 	int i, ret;
 
-	for (kern_id = 0; kern_id < 256; kern_id++) {
-		ret = msgctl(kern_id, MSG_STAT, &ds);
-		if (ret < 0) {
-			if (errno == EINVAL)
-				continue;
-			ksft_test_result_fail("Failed to get stats for IPC queue with id %d\n",
-					kern_id);
-			return -errno;
-		}
-
-		if (ret == msgque->msq_id)
-			break;
+	ret = msgctl(msgque->msq_id, IPC_STAT, &ds);
+	if (ret < 0) {
+		ksft_test_result_fail("Failed to get stats for IPC queue with id %d\n",
+				      msgque->msq_id);
+		return -errno;
 	}
 
 	msgque->messages = malloc(sizeof(struct msg1) * ds.msg_qnum);
-- 
2.47.3