#include "libudev.h"
#include "libudev-private.h"
#include "socket-util.h"
+#include "missing.h"
/**
* SECTION:libudev-monitor
return udev_monitor;
}
+/* we consider udev running when /dev is on devtmpfs */
+static bool udev_has_devtmpfs(struct udev *udev) {
+ struct file_handle *h;
+ int mount_id;
+ _cleanup_fclose_ FILE *f = NULL;
+ char line[LINE_MAX], *e;
+ int r;
+
+ h = alloca(MAX_HANDLE_SZ);
+ h->handle_bytes = MAX_HANDLE_SZ;
+ r = name_to_handle_at(AT_FDCWD, "/dev", h, &mount_id, 0);
+ if (r < 0)
+ return false;
+
+
+ f = fopen("/proc/self/mountinfo", "re");
+ if (!f)
+ return false;
+
+ FOREACH_LINE(line, f, return false) {
+ int mid;
+
+ if (sscanf(line, "%i", &mid) != 1)
+ continue;
+
+ if (mid != mount_id)
+ continue;
+
+ e = strstr(line, " - ");
+ if (!e)
+ continue;
+
+ /* accept any name that starts with the currently expected type */
+ if (startswith(e + 3, "devtmpfs"))
+ return true;
+ }
+
+ return false;
+}
+
+/* we consider udev running when we have running udev service */
+static bool udev_has_service(struct udev *udev) {
+ struct udev_queue *queue;
+ bool active;
+
+ queue = udev_queue_new(udev);
+ if (!queue)
+ return false;
+
+ active = udev_queue_get_udev_is_active(queue);
+ udev_queue_unref(queue);
+
+ return active;
+}
+
struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
{
struct udev_monitor *udev_monitor;
if (name == NULL)
group = UDEV_MONITOR_NONE;
- else if (streq(name, "udev"))
- group = UDEV_MONITOR_UDEV;
- else if (streq(name, "kernel"))
+ else if (streq(name, "udev")) {
+ /*
+ * We do not support subscribing to uevents if no instance of
+ * udev is running. Uevents would otherwise broadcast the
+ * processing data of the host into containers, which is not
+ * desired.
+ *
+ * Containers will currently not get any udev uevents, until
+ * a supporting infrastructure is available.
+ *
+ * We do not set a netlink multicast group here, so the socket
+ * will not receive any messages.
+ */
+ if (!udev_has_service(udev) && !udev_has_devtmpfs(udev)) {
+ udev_dbg(udev, "the udev service seems not to be active, disable the monitor\n");
+ group = UDEV_MONITOR_NONE;
+ } else
+ group = UDEV_MONITOR_UDEV;
+ } else if (streq(name, "kernel"))
group = UDEV_MONITOR_KERNEL;
else
return NULL;