kernel: socket: Block if cmsg queue is empty

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/kern/kern_socket.c b/sys/kern/kern_socket.c
index 42f31d9..065245b 100644
--- a/sys/kern/kern_socket.c
+++ b/sys/kern/kern_socket.c
@@ -32,6 +32,7 @@
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/namei.h>
+#include <sys/sched.h>
 #include <sys/errno.h>
 #include <sys/syslog.h>
 #include <sys/filedesc.h>
@@ -477,6 +478,12 @@ recvmsg(int socket, struct msghdr *msg, int flags)
     clp = &ksock->cmsg_list;
     cmsg = TAILQ_FIRST(&clp->list);
 
+    /* Empty? */
+    while (cmsg == NULL) {
+        sched_yield();
+        cmsg = TAILQ_FIRST(&clp->list);
+    }
+
     while (cmsg != NULL) {
         cmsghdr = &cmsg->hdr;