udev: remove seqnum API and all assumptions about seqnums

The way the kernel namespaces have been implemented breaks assumptions
udev made regarding uevent sequence numbers. Creating devices in a
namespace "steals" uevents and its sequence numbers from the host. It
confuses the "udevadmin settle" logic, which might block until util a
timeout is reached, even when no uevent is pending.

Remove any assumptions about sequence numbers and deprecate libudev's
API exposing these numbers; none of that can reliably be used anymore
when namespaces are involved.

Author: kaysievers

Makefile.am

@@ -2587,8 +2587,7 @@ noinst_LTLIBRARIES += \
 
 libudev_internal_la_SOURCES =\
 	$(libudev_la_SOURCES) \
-	src/libudev/libudev-device-private.c \
-	src/libudev/libudev-queue-private.c
+	src/libudev/libudev-device-private.c
 
 libudev_internal_la_CFLAGS = \
 	$(AM_CFLAGS) \
@@ -5169,6 +5168,9 @@ test_libsystemd_sym_LDADD = \
 
 test_libudev_sym_SOURCES = \
 	test-libudev-sym.c
+test_libudev_sym_CFLAGS = \
+	$(AM_CFLAGS) \
+	-Wno-deprecated-declarations
 test_libudev_sym_LDADD = \
 	libudev.la
 

man/udevadm.xml

@@ -338,35 +338,13 @@
             return immediately.</para>
           </listitem>
         </varlistentry>
-        <varlistentry>
-          <term><option>-s</option></term>
-          <term><option>--seq-start=<replaceable>SEQNUM</replaceable></option></term>
-          <listitem>
-            <para>Wait only for events after the given sequence
-            number.</para>
-          </listitem>
-        </varlistentry>
-        <varlistentry>
-          <term><option>-e</option></term>
-          <term><option>--seq-end=<replaceable>SEQNUM</replaceable></option></term>
-          <listitem>
-            <para>Wait only for events before the given sequence number.</para>
-          </listitem>
-        </varlistentry>
         <varlistentry>
           <term><option>-E</option></term>
           <term><option>--exit-if-exists=<replaceable>FILE</replaceable></option></term>
           <listitem>
             <para>Stop waiting if file exists.</para>
           </listitem>
         </varlistentry>
-        <varlistentry>
-          <term><option>-q</option></term>
-          <term><option>--quiet</option></term>
-          <listitem>
-            <para>Do not print any output, like the remaining queue entries when reaching the timeout.</para>
-          </listitem>
-        </varlistentry>
         <varlistentry>
           <term><option>-h</option></term>
           <term><option>--help</option></term>

src/libudev/libudev-monitor.c

@@ -146,21 +146,6 @@ static bool udev_has_devtmpfs(struct udev *udev) {
         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;
@@ -184,7 +169,7 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
                  * 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)) {
+                if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) {
                         udev_dbg(udev, "the udev service seems not to be active, disable the monitor\n");
                         group = UDEV_MONITOR_NONE;
                 } else