slirp: Handle error returns from slirp_send() in sosendoob()

The code in sosendoob() assumes that slirp_send() always
succeeds, but it might return an OS error code (for instance
if the other end has disconnected). Catch these and return
the caller either -1 on error or the number of urgent bytes
actually written. (None of the callers check this return
value currently, though.)

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>

1 files changed, 19 insertions, 17 deletions

diff --git a/socket.c b/socket.c
index 859ff35..4151eb8 100644
--- a/socket.c
+++ b/socket.c
@@ -342,39 +342,41 @@ int sosendoob(struct socket *so)
         /* We can send it directly */
         n = slirp_send(so, sb->sb_rptr, so->so_urgc,
                        (MSG_OOB)); /* |MSG_DONTWAIT)); */
-        so->so_urgc -= n;
-
-        DEBUG_MISC((dfd,
-                    " --- sent %d bytes urgent data, %d urgent bytes left\n", n,
-                    so->so_urgc));
     } else {
         /*
          * Since there's no sendv or sendtov like writev,
          * we must copy all data to a linear buffer then
          * send it all
          */
+        uint32_t urgc = so->so_urgc;
         len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
-        if (len > so->so_urgc)
-            len = so->so_urgc;
+        if (len > urgc) {
+            len = urgc;
+        }
         memcpy(buff, sb->sb_rptr, len);
-        so->so_urgc -= len;
-        if (so->so_urgc) {
+        urgc -= len;
+        if (urgc) {
             n = sb->sb_wptr - sb->sb_data;
-            if (n > so->so_urgc)
-                n = so->so_urgc;
+            if (n > urgc) {
+                n = urgc;
+            }
             memcpy((buff + len), sb->sb_data, n);
-            so->so_urgc -= n;
             len += n;
         }
         n = slirp_send(so, buff, len, (MSG_OOB)); /* |MSG_DONTWAIT)); */
+    }
+
 #ifdef DEBUG
-        if (n != len)
-            DEBUG_ERROR((dfd, "Didn't send all data urgently XXXXX\n"));
+    if (n != len) {
+        DEBUG_ERROR((dfd, "Didn't send all data urgently XXXXX\n"));
+    }
 #endif
-        DEBUG_MISC((dfd,
-                    " ---2 sent %d bytes urgent data, %d urgent bytes left\n",
-                    n, so->so_urgc));
+    if (n < 0) {
+        return n;
     }
+    so->so_urgc -= n;
+    DEBUG_MISC((dfd, " ---2 sent %d bytes urgent data, %d urgent bytes left\n",
+                n, so->so_urgc));
 
     sb->sb_cc -= n;
     sb->sb_rptr += n;