Commit 8db165b3 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Anthony Liguori

main-loop: narrow win32 pollfds_fill() event bitmasks

pollfds_fill() and pollfds_poll() translate GPollFD to rfds/wfds/xfds
for sockets on win32.  select(2) is the underlying system call which is
used to monitor sockets for activity.

Currently file descriptors that monitor G_IO_ERR will be included in
both rfds and wfds.  As a result, select(2) will report writability on
file descriptors where we only really wanted to monitor readability
(with errors).

slirp_pollfds_poll() hit this issue: UDP sockets are blocking sockets so
we hang in sorecvfrom() when G_IO_ERR is set due to the socket being
writable (we only wanted to check for readability).

This patch fixes the slirp_pollfds_poll() hang.
Signed-off-by: default avatarStefan Hajnoczi <>
Signed-off-by: default avatarAnthony Liguori <>
parent 6d46895b
......@@ -333,11 +333,11 @@ static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
int fd = pfd->fd;
int events = pfd->events;
if (events & (G_IO_IN | G_IO_HUP | G_IO_ERR)) {
if (events & G_IO_IN) {
FD_SET(fd, rfds);
nfds = MAX(nfds, fd);
if (events & (G_IO_OUT | G_IO_ERR)) {
if (events & G_IO_OUT) {
FD_SET(fd, wfds);
nfds = MAX(nfds, fd);
......@@ -360,10 +360,10 @@ static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
int revents = 0;
if (FD_ISSET(fd, rfds)) {
revents |= G_IO_IN | G_IO_HUP | G_IO_ERR;
revents |= G_IO_IN;
if (FD_ISSET(fd, wfds)) {
revents |= G_IO_OUT | G_IO_ERR;
revents |= G_IO_OUT;
if (FD_ISSET(fd, xfds)) {
revents |= G_IO_PRI;
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