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authorKay Sievers <kay@vrfy.org>2013-12-18 22:01:31 +0100
committerKay Sievers <kay@vrfy.org>2013-12-18 22:01:31 +0100
commitdf32a1caafe881fc7850a9b569179b877198685f (patch)
tree09a0f786943c21e2b2f2d7952c6143cc9fccc6e7
parentec76ec1fde7da753676b18ff45926740fcd08072 (diff)
libudev: disable monitor inside a container
Uevents are events of the host, which should not leak into a container. Containers do not support hotplug at the moment, and devices and uevents are not namespace aware.
-rw-r--r--TODO6
-rw-r--r--src/libudev/libudev-monitor.c65
2 files changed, 64 insertions, 7 deletions
diff --git a/TODO b/TODO
index 1500d6b1bd..8025169033 100644
--- a/TODO
+++ b/TODO
@@ -1,10 +1,4 @@
Bugfixes:
-* sort-out libudev's is_initialized logic for:
- - enumerate devices:
- - is_initialized is true if a database exists
- - in-container devices:
- - is_initialized is always false, because there is no database
-
* enabling an instance unit creates a pointless link, and
the unit will be started with getty@getty.service:
$ systemctl enable getty@.service
diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index e07e462af3..4586b3d4c7 100644
--- a/src/libudev/libudev-monitor.c
+++ b/src/libudev/libudev-monitor.c
@@ -35,6 +35,7 @@
#include "libudev.h"
#include "libudev-private.h"
#include "socket-util.h"
+#include "missing.h"
/**
* SECTION:libudev-monitor
@@ -105,6 +106,62 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev)
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);
+
+ 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) {
+ _cleanup_free_ char *opts = NULL;
+ 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;
@@ -127,8 +184,14 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
* is running. Uevents would otherwise broadcast the processing data
* of the host into containers, which is not acceptable. Containers
* will currently just not get any uevents.
+ *
+ * We clear the netlink multicast group here, so the socket will
+ * not receive any messages.
*/
-
+ if (!udev_has_service(udev) && !udev_has_devtmpfs(udev)) {
+ udev_dbg(udev, "udev seems not to be active, disable the monitor\n");
+ group = 0;
+ }
udev_monitor = udev_monitor_new(udev);
if (udev_monitor == NULL)