Re: [libvirt PATCH] qemu: honour fatal errors dealing with qemu slirp helper

Currently all errors from qemuInterfacePrepareSlirp() are completely ignored by the callers. The intention is that missing qemu-slirp binary should cause the caller to fallback to the built-in slirp impl. Many of the possible errors though should indeed be considered fatal. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; ---

src/qemu/qemu_hotplug.c | 7 +++++-- src/qemu/qemu_interface.c | 21 +++++++++++++++------ src/qemu/qemu_interface.h | 5 +++-- src/qemu/qemu_process.c | 8 ++++++-- src/qemu/qemu_slirp.c | 3 --- 5 files changed, 29 insertions(+), 15 deletions(-) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 79fc8baa5c..dc998236de 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1311,9 +1311,12 @@ qemuDomainAttachNetDevice(virQEMUDriverPtr driver, case VIR_DOMAIN_NET_TYPE_USER: if (!priv->disableSlirp && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE)) { - qemuSlirpPtr slirp = qemuInterfacePrepareSlirp(driver, net); + qemuSlirpPtr slirp = NULL; + int rv = qemuInterfacePrepareSlirp(driver, net, &slirp); - if (!slirp) + if (rv == -1) + return -1; + if (rv == 0) break; QEMU_DOMAIN_NETWORK_PRIVATE(net)->slirp = slirp; diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c index cbf3d99981..b4ab809970 100644 --- a/src/qemu/qemu_interface.c +++ b/src/qemu/qemu_interface.c @@ -636,30 +636,39 @@ qemuInterfaceBridgeConnect(virDomainDefPtr def, } -qemuSlirpPtr +/* + * Returns: -1 on error, 0 if slirp isn't available, 1 on succcess + */ +int qemuInterfacePrepareSlirp(virQEMUDriverPtr driver, - virDomainNetDefPtr net) + virDomainNetDefPtr net, + qemuSlirpPtr *slirpret) { g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver); g_autoptr(qemuSlirp) slirp = NULL; size_t i; + if (!cfg->slirpHelperName || + !virFileExists(cfg->slirpHelperName)) + return 0; /* fallback to builtin slirp impl */ + if (!(slirp = qemuSlirpNewForHelper(cfg->slirpHelperName))) - return NULL; + return -1; for (i = 0; i < net->guestIP.nips; i++) { const virNetDevIPAddr *ip = net->guestIP.ips[i]; if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET) && !qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_IPV4)) - return NULL; + return 0; if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6) && !qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_IPV6)) - return NULL; + return 0; } - return g_steal_pointer(&slirp); + *slirpret = g_steal_pointer(&slirp); + return 1; } diff --git a/src/qemu/qemu_interface.h b/src/qemu/qemu_interface.h index 3dcefc6a12..b5e91e3ab2 100644 --- a/src/qemu/qemu_interface.h +++ b/src/qemu/qemu_interface.h @@ -56,5 +56,6 @@ int qemuInterfaceOpenVhostNet(virDomainDefPtr def, int *vhostfd, size_t *vhostfdSize) G_GNUC_NO_INLINE; -qemuSlirpPtr qemuInterfacePrepareSlirp(virQEMUDriverPtr driver, - virDomainNetDefPtr net); +int qemuInterfacePrepareSlirp(virQEMUDriverPtr driver, + virDomainNetDefPtr net, + qemuSlirpPtr *slirp); diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 5bc76a75e3..59206a17fb 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -5697,9 +5697,13 @@ qemuProcessNetworkPrepareDevices(virQEMUDriverPtr driver, } else if (actualType == VIR_DOMAIN_NET_TYPE_USER && !priv->disableSlirp && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DBUS_VMSTATE)) { - qemuSlirpPtr slirp = qemuInterfacePrepareSlirp(driver, net); + qemuSlirpPtr slirp = NULL; + int rv = qemuInterfacePrepareSlirp(driver, net, &slirp); - QEMU_DOMAIN_NETWORK_PRIVATE(net)->slirp = slirp; + if (rv == -1) + return -1; + if (rv == 1) + QEMU_DOMAIN_NETWORK_PRIVATE(net)->slirp = slirp; } } diff --git a/src/qemu/qemu_slirp.c b/src/qemu/qemu_slirp.c index d2e4ed79be..dfb36125f0 100644 --- a/src/qemu/qemu_slirp.c +++ b/src/qemu/qemu_slirp.c @@ -101,9 +101,6 @@ qemuSlirpNewForHelper(const char *helper) virJSONValuePtr featuresJSON; size_t i, nfeatures; - if (!helper) - return NULL; - slirp = qemuSlirpNew(); if (!slirp) { virReportError(VIR_ERR_INTERNAL_ERROR,