[libvirt] virCommandProcessIO: hangs on poll()
recent qemu (git resp) with param like:
#>qemu-kvm -S -no-user-config -nodefaults -nographic -M none -qmp
monarg -pidfile pidfile
will just hangs forever. no any output or errors .
and when libvirt Try to get caps via QMP qemuCaps. it run above command.
so virCommandProcessIO call poll() will be hangs forever.
i patch the libvirt (git resp) with :
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 50712b0..915edaa 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -2377,7 +2377,6 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps,
virCommandClearCaps(cmd);
virCommandSetGID(cmd, runGid);
virCommandSetUID(cmd, runUid);
-
if (virCommandRun(cmd, &status) < 0)
goto cleanup;
diff --git a/src/util/vircommand.c b/src/util/vircommand.c
index ac56a63..84738f9 100644
--- a/src/util/vircommand.c
+++ b/src/util/vircommand.c
@@ -1824,6 +1824,7 @@ virCommandProcessIO(virCommandPtr cmd)
int i;
struct pollfd fds[3];
int nfds = 0;
+ int pfds = 0;
if (cmd->inpipe != -1) {
fds[nfds].fd = cmd->inpipe;
@@ -1846,8 +1847,8 @@ virCommandProcessIO(virCommandPtr cmd)
if (nfds == 0)
break;
-
- if (poll(fds, nfds, -1) < 0) {
+ pfds = poll(fds, nfds, -1);
+ if ( pfds< 0) {
if (errno == EAGAIN || errno == EINTR)
continue;
virReportSystemError(errno, "%s",
@@ -1855,10 +1856,22 @@ virCommandProcessIO(virCommandPtr cmd)
goto cleanup;
}
- for (i = 0; i < nfds ; i++) {
- if (fds[i].revents & (POLLIN | POLLHUP | POLLERR) &&
+ for (i = 0; i < pfds ; i++) {
+ if (fds[i].revents & (POLLHUP | POLLRDHUP | POLLERR |
POLLNVAL))
+ {
+ if (fds[i].fd == errfd) {
+ VIR_DEBUG("hangup on stderr");
+ } else if (fds[i].fd == outfd) {
+ VIR_DEBUG("hangup on stdout");
+ } else {
+ VIR_DEBUG("hangup on stdin");
+ }
+ errfd = -1;
+ }
+
+ if (fds[i].revents & (POLLIN | POLLHUP | POLLRDHUP |
POLLERR | POLLNVAL) &&
(fds[i].fd == errfd || fds[i].fd == outfd)) {
- char data[1024];
+ char data[1024*2];
char **buf;
size_t *len;
int done;
So everythings is OK.
i use gentoo OS. qemu git source and libvirt git source.