slirp: Handle error returns from sosendoob()v2.10.0-rc1v2.10.0-rc0

sosendoob() can return a failure code, but all its callers ignore it.
This is OK in sbappend(), as the comment there states -- we will try
again later in sowrite(). Add a (void) cast to tell Coverity so.
In sowrite() we do need to check the return value -- we should handle
a write failure in sosendoob() the same way we handle a write failure
for the normal data.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

2 files changed, 19 insertions, 8 deletions

diff --git a/sbuf.c b/sbuf.c
index 8a0a6a9..01f9a46 100644
--- a/sbuf.c
+++ b/sbuf.c
@@ -88,7 +88,7 @@ void sbappend(struct socket *so, struct mbuf *m)
     if (so->so_urgc) {
         sbappendsb(&so->so_rcv, m);
         m_free(m);
-        sosendoob(so);
+        (void)sosendoob(so);
         return;
     }
 
diff --git a/socket.c b/socket.c
index 4151eb8..b346e1c 100644
--- a/socket.c
+++ b/socket.c
@@ -401,7 +401,15 @@ int sowrite(struct socket *so)
     DEBUG_ARG("so = %p", so);
 
     if (so->so_urgc) {
-        sosendoob(so);
+        uint32_t expected = so->so_urgc;
+        if (sosendoob(so) < expected) {
+            /* Treat a short write as a fatal error too,
+             * rather than continuing on and sending the urgent
+             * data as if it were non-urgent and leaving the
+             * so_urgc count wrong.
+             */
+            goto err_disconnected;
+        }
         if (sb->sb_cc == 0)
             return 0;
     }
@@ -448,12 +456,7 @@ int sowrite(struct socket *so)
         return 0;
 
     if (nn <= 0) {
-        DEBUG_MISC(
-            (dfd, " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
-             so->so_state, errno));
-        sofcantsendmore(so);
-        tcp_sockclosed(sototcpcb(so));
-        return -1;
+        goto err_disconnected;
     }
 
 #ifndef HAVE_READV
@@ -480,6 +483,14 @@ int sowrite(struct socket *so)
         sofcantsendmore(so);
 
     return nn;
+
+err_disconnected:
+    DEBUG_MISC((dfd,
+                " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
+                so->so_state, errno));
+    sofcantsendmore(so);
+    tcp_sockclosed(sototcpcb(so));
+    return -1;
 }
 
 /*