From 7e17af1ca7a0f9cb990f83c3e03e379520257683 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 16 Oct 2025 13:42:59 -0400
Subject: kern: iotap: Return -ENOTSUP if I/O tap op is NULL

If an I/O tap operation is unimplemented, return the -ENOTSUP error code
before trying to call it.

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/os/os_iotap.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'src')

diff --git a/src/sys/os/os_iotap.c b/src/sys/os/os_iotap.c
index 238acfe..54d1157 100644
--- a/src/sys/os/os_iotap.c
+++ b/src/sys/os/os_iotap.c
@@ -130,6 +130,9 @@ iotap_mux(const char *name, struct iotap_msg *msg)
     ops = desc.ops;
     switch (msg->opcode) {
     case IOTAP_OPC_READ:
+        if (ops->read == NULL) {
+            return -ENOTSUP;
+        }
         return ops->read(&desc, msg->buf, msg->len);
     }
 
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