slirp: Gcc 9 -O3 fix

Gcc 9 needs some convincing that sopreprbuf really is going to fill
in iov in the call from soreadbuf, even though the failure case
shouldn't happen.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190415121740.9881-1-dgilbert@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/slirp/src/socket.c b/slirp/src/socket.c
index 4a3c935e25..bb752fdcae 100644
--- a/slirp/src/socket.c
+++ b/slirp/src/socket.c
@@ -171,6 +171,7 @@ int
 soread(struct socket *so)
 {
 	int n, nn;
+	size_t buf_len;
 	struct sbuf *sb = &so->so_snd;
 	struct iovec iov[2];
 
@@ -181,7 +182,8 @@ soread(struct socket *so)
 	 * No need to check if there's enough room to read.
 	 * soread wouldn't have been called if there weren't
 	 */
-	sopreprbuf(so, iov, &n);
+	buf_len = sopreprbuf(so, iov, &n);
+	assert(buf_len != 0);
 
 	nn = recv(so->s, iov[0].iov_base, iov[0].iov_len,0);
 	if (nn <= 0) {
@@ -257,6 +259,7 @@ int soreadbuf(struct socket *so, const char *buf, int size)
 	 * No need to check if there's enough room to read.
 	 * soread wouldn't have been called if there weren't
 	 */
+	assert(size > 0);
 	if (sopreprbuf(so, iov, &n) < size)
         goto err;