[Qemu-devel] [PATCH] qemu-char: Fix missed data on unix socket

[pyssling@ludd.ltu.se]

From: Nils Carlson <pyssling@ludd.ltu.se>

Commit 812c1057 introduced HUP detection on unix and tcp sockets prior
to a read in tcp_chr_read. This unfortunately broke CloudStack 4.2
which relied on the old behaviour where data on a socket was readable
even if a HUP was present.

On Linux a working solution seems to be to simply check the HUP after
reading available data, while keeping the original behaviour for windows.

There is then a divergence in behaviour for the two platforms, but this
seems better than breaking a whole software stack.

Signed-off-by: Nils Carlson <pyssling@ludd.ltu.se>
---
 qemu-char.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/qemu-char.c b/qemu-char.c
index 617e034..cfd9b70 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2847,11 +2847,13 @@ static gboolean tcp_chr_read(GIOChannel *chan, GIOCondition cond, void *opaque)
     uint8_t buf[READ_BUF_LEN];
     int len, size;
 
+#ifdef _WIN32
     if (cond & G_IO_HUP) {
         /* connection closed */
         tcp_chr_disconnect(chr);
         return TRUE;
     }
+#endif
 
     if (!s->connected || s->max_size <= 0) {
         return TRUE;
@@ -2860,7 +2862,7 @@ static gboolean tcp_chr_read(GIOChannel *chan, GIOCondition cond, void *opaque)
     if (len > s->max_size)
         len = s->max_size;
     size = tcp_chr_recv(chr, (void *)buf, len);
-    if (size == 0) {
+    if (size == 0 || (size < 0 && cond & G_IO_HUP)) {
         /* connection closed */
         tcp_chr_disconnect(chr);
     } else if (size > 0) {
-- 
1.7.10.4