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qemu-char: Fix missed data on unix socket 

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.

A working solution is to properly check the return values from recv,
handling a closed socket once there is no more data to read.

Also enable polling for G_IO_NVAL to ensure the callback is called
for all possible events as these should now be possible to handle
with the improved error detection.

Signed-off-by: Nils Carlson <pyssling@ludd.ltu.se>
Message-Id: <1437338396-22336-1-git-send-email-pyssling@ludd.ltu.se>
[Do not handle EINTR; use socket_error(). - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nils Carlson 2015-07-19 20:39:56 +00:00 committed by Paolo Bonzini
parent 9172f428af
commit 4bf1cb03fb
1 changed files with 5 additions and 8 deletions
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13
qemu-char.c
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@ -807,7 +807,8 @@ static gboolean io_watch_poll_prepare(GSource *source, gint *timeout_)
}
if (now_active) {
iwp->src = g_io_create_watch(iwp->channel, G_IO_IN | G_IO_ERR | G_IO_HUP);
iwp->src = g_io_create_watch(iwp->channel,
G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
g_source_attach(iwp->src, NULL);
} else {
@ -2856,12 +2857,6 @@ static gboolean tcp_chr_read(GIOChannel *chan, GIOCondition cond, void *opaque)
uint8_t buf[READ_BUF_LEN];
int len, size;
if (cond & G_IO_HUP) {
/* connection closed */
tcp_chr_disconnect(chr);
return TRUE;
}
if (!s->connected || s->max_size <= 0) {
return TRUE;
}
@ -2869,7 +2864,9 @@ 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 &&
socket_error() != EAGAIN && socket_error() != EWOULDBLOCK)) {
/* connection closed */
tcp_chr_disconnect(chr);
} else if (size > 0) {