Re: [libvirt PATCH v2 09/16] nodedev: add an mdevctl thread

We need to peridocally query mdevctl for changes to device definitions since an administrator can define new devices with mdevctl outside of libvirt. In order to do this, a new thread is created to handle the querying. In the future, mdevctl may add a way to signal device add / remove via events, but for now we resort to a bit of a workaround: monitoring the mdevctl config directories for changes to files. When a change is detected, we query mdevctl and update our device list. Signed-off-by: Jonathon Jongsma <jjongsma(a)redhat.com&gt; --- src/node_device/node_device_udev.c | 182 +++++++++++++++++++++++++++++ 1 file changed, 182 insertions(+) diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c index e06584a3dc..a85418e549 100644 --- a/src/node_device/node_device_udev.c +++ b/src/node_device/node_device_udev.c @@ -1858,6 +1969,58 @@ udevPCITranslateInit(bool privileged G_GNUC_UNUSED) } +/* Recursively monitors dir and any subdirectory for file changes and returns a + * GList of GFileMonitor objects */ +static GList* +monitorDirRecursively(GFile *dir, + GCallback changed_cb, + gpointer user_data) +{ + GList *monitors = NULL;

+ g_autoptr(GFileInfo) dirinfo = NULL;

+ g_autoptr(GError) error = NULL; + g_autoptr(GFileEnumerator) children = NULL; + GFileMonitor *mon; + + if (!(children = g_file_enumerate_children(dir, "standard::*", + G_FILE_QUERY_INFO_NONE, NULL, &error))) { + if (error->code == G_IO_ERROR_NOT_DIRECTORY) + return NULL; + goto bail;

+ } + + if (!(mon = g_file_monitor(dir, G_FILE_MONITOR_NONE, NULL, &error))) + goto bail; + + g_signal_connect(mon, "changed", changed_cb, user_data); + monitors = g_list_append(monitors, mon); + + while (true) { + GFileInfo *info; + GFile *child; + GList *child_monitors = NULL; + + if (!g_file_enumerator_iterate(children, &info, &child, NULL, &error)) + goto bail; + if (!info) + break; + + child_monitors = monitorDirRecursively(child, changed_cb, user_data); + if (child_monitors) + monitors = g_list_concat(monitors, child_monitors); + } + + return monitors; + + bail: + if (error) + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unable to monitor directory: %s"), error->message);

+ + g_list_free_full(monitors, g_object_unref); + return NULL; +} + static int nodeStateInitialize(bool privileged, const char *root, @@ -1867,6 +2030,8 @@ nodeStateInitialize(bool privileged, udevEventDataPtr priv = NULL; struct udev *udev = NULL; virThread enumThread; + g_autoptr(GError) error = NULL;

+ g_autoptr(GFile) mdevctlConfigDir = g_file_new_for_path("/etc/mdevctl.d"); if (root != NULL) { virReportError(VIR_ERR_INVALID_ARG, "%s", @@ -1969,6 +2134,23 @@ nodeStateInitialize(bool privileged, if (priv->watch == -1) goto unlock; + if (virThreadCreateFull(&priv->mdevctlThread, true, mdevctlThread, + "mdevctl-event", false, NULL) < 0) { + virReportSystemError(errno, "%s", + _("failed to create mdevctl handler thread")); + goto unlock; + } + + /* mdevctl may add notification events in the future: + * https://github.com/mdevctl/mdevctl/issues/27. For now, fall back to + * monitoring the mdevctl configuration directory for changes. + * mdevctl configuration is stored in a directory tree within + * /etc/mdevctl.d/. There is a directory for each parent device, which + * contains a file defining each mediated device */ + priv->mdevctl_monitors = monitorDirRecursively(mdevctlConfigDir, + G_CALLBACK(mdevctlEventHandleCallback), + priv); + virObjectUnlock(priv); /* Create a fictional 'computer' device to root the device tree. */ -- 2.26.2