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.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

5 files changed, 30 insertions, 708 deletions

diff --git a/src/libudev/Makefile.am b/src/libudev/Makefile.am
index 3a0de58865..c9c4d42fb8 100644
--- a/src/libudev/Makefile.am
+++ b/src/libudev/Makefile.am
@@ -88,8 +88,7 @@ libudev_la_LDFLAGS = \
 
 
 libudev_private_la_SOURCES =\
-	libudev-device-private.c \
-	libudev-queue-private.c
+	libudev-device-private.c
 
 libudev_private_la_LIBADD =\
 	libudev.la
diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index ff522b8607..43fd8762da 100644
--- a/src/libudev/libudev-monitor.c
+++ b/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
diff --git a/src/libudev/libudev-queue-private.c b/src/libudev/libudev-queue-private.c
deleted file mode 100644
index d5a2b503dd..0000000000
--- a/src/libudev/libudev-queue-private.c
+++ /dev/null
@@ -1,406 +0,0 @@
-/***
-  This file is part of systemd.
-
-  Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
-  Copyright 2009 Alan Jenkins <alan-jenkins@tuffmail.co.uk>
-
-  systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU Lesser General Public License as published by
-  the Free Software Foundation; either version 2.1 of the License, or
-  (at your option) any later version.
-
-  systemd is distributed in the hope that it will be useful, but
-  WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-  Lesser General Public License for more details.
-
-  You should have received a copy of the GNU Lesser General Public License
-  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-
-/*
- * DISCLAIMER - The file format mentioned here is private to udev/libudev,
- *              and may be changed without notice.
- *
- * The udev event queue is exported as a binary log file.
- * Each log record consists of a sequence number followed by the device path.
- *
- * When a new event is queued, its details are appended to the log.
- * When the event finishes, a second record is appended to the log
- * with the same sequence number but a devpath len of 0.
- *
- * Example:
- *        { 0x0000000000000001 }
- *        { 0x0000000000000001, 0x0019, "/devices/virtual/mem/null" },
- *        { 0x0000000000000002, 0x001b, "/devices/virtual/mem/random" },
- *        { 0x0000000000000001, 0x0000 },
- *        { 0x0000000000000003, 0x0019, "/devices/virtual/mem/zero" },
- *
- * Events 2 and 3 are still queued, but event 1 has finished.
- *
- * The queue does not grow indefinitely. It is periodically re-created
- * to remove finished events. Atomic rename() makes this transparent to readers.
- *
- * The queue file starts with a single sequence number which specifies the
- * minimum sequence number in the log that follows. Any events prior to this
- * sequence number have already finished.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <dirent.h>
-#include <limits.h>
-#include <errno.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#include "libudev.h"
-#include "libudev-private.h"
-
-static int rebuild_queue_file(struct udev_queue_export *udev_queue_export);
-
-struct udev_queue_export {
-        struct udev *udev;
-        int queued_count;        /* number of unfinished events exported in queue file */
-        FILE *queue_file;
-        unsigned long long int seqnum_max;        /* earliest sequence number in queue file */
-        unsigned long long int seqnum_min;        /* latest sequence number in queue file */
-        int waste_bytes;                        /* queue file bytes wasted on finished events */
-};
-
-struct udev_queue_export *udev_queue_export_new(struct udev *udev)
-{
-        struct udev_queue_export *udev_queue_export;
-        unsigned long long int initial_seqnum;
-
-        if (udev == NULL)
-                return NULL;
-
-        udev_queue_export = new0(struct udev_queue_export, 1);
-        if (udev_queue_export == NULL)
-                return NULL;
-        udev_queue_export->udev = udev;
-
-        initial_seqnum = udev_get_kernel_seqnum(udev);
-        udev_queue_export->seqnum_min = initial_seqnum;
-        udev_queue_export->seqnum_max = initial_seqnum;
-
-        udev_queue_export_cleanup(udev_queue_export);
-        if (rebuild_queue_file(udev_queue_export) != 0) {
-                free(udev_queue_export);
-                return NULL;
-        }
-
-        return udev_queue_export;
-}
-
-struct udev_queue_export *udev_queue_export_unref(struct udev_queue_export *udev_queue_export)
-{
-        if (udev_queue_export == NULL)
-                return NULL;
-        if (udev_queue_export->queue_file != NULL)
-                fclose(udev_queue_export->queue_file);
-        free(udev_queue_export);
-        return NULL;
-}
-
-void udev_queue_export_cleanup(struct udev_queue_export *udev_queue_export)
-{
-        if (udev_queue_export == NULL)
-                return;
-        unlink("/run/udev/queue.tmp");
-        unlink("/run/udev/queue.bin");
-}
-
-static int skip_to(FILE *file, long offset)
-{
-        long old_offset;
-
-        /* fseek may drop buffered data, avoid it for small seeks */
-        old_offset = ftell(file);
-        if (offset > old_offset && offset - old_offset <= BUFSIZ) {
-                size_t skip_bytes = offset - old_offset;
-                char *buf = alloca(skip_bytes);
-
-                if (fread(buf, skip_bytes, 1, file) != skip_bytes)
-                        return -1;
-        }
-
-        return fseek(file, offset, SEEK_SET);
-}
-
-struct queue_devpaths {
-        unsigned int devpaths_first;        /* index of first queued event */
-        unsigned int devpaths_size;
-        long devpaths[];                /* seqnum -> offset of devpath in queue file (or 0) */
-};
-
-/*
- * Returns a table mapping seqnum to devpath file offset for currently queued events.
- * devpaths[i] represents the event with seqnum = i + udev_queue_export->seqnum_min.
- */
-static struct queue_devpaths *build_index(struct udev_queue_export *udev_queue_export)
-{
-        struct queue_devpaths *devpaths;
-        unsigned long long int range;
-        long devpath_offset;
-        ssize_t devpath_len;
-        unsigned long long int seqnum;
-        unsigned long long int n;
-        unsigned int i;
-
-        /* seek to the first event in the file */
-        rewind(udev_queue_export->queue_file);
-        udev_queue_read_seqnum(udev_queue_export->queue_file, &seqnum);
-
-        /* allocate the table */
-        range = udev_queue_export->seqnum_min - udev_queue_export->seqnum_max;
-        if (range - 1 > INT_MAX) {
-                udev_err(udev_queue_export->udev, "queue file overflow\n");
-                return NULL;
-        }
-        devpaths = malloc0(sizeof(struct queue_devpaths) + (range + 1) * sizeof(long));
-        if (devpaths == NULL)
-                return NULL;
-        devpaths->devpaths_size = range + 1;
-
-        /* read all records and populate the table */
-        for (;;) {
-                if (udev_queue_read_seqnum(udev_queue_export->queue_file, &seqnum) < 0)
-                        break;
-                n = seqnum - udev_queue_export->seqnum_max;
-                if (n >= devpaths->devpaths_size)
-                        goto read_error;
-
-                devpath_offset = ftell(udev_queue_export->queue_file);
-                devpath_len = udev_queue_skip_devpath(udev_queue_export->queue_file);
-                if (devpath_len < 0)
-                        goto read_error;
-
-                if (devpath_len > 0)
-                        devpaths->devpaths[n] = devpath_offset;
-                else
-                        devpaths->devpaths[n] = 0;
-        }
-
-        /* find first queued event */
-        for (i = 0; i < devpaths->devpaths_size; i++) {
-                if (devpaths->devpaths[i] != 0)
-                        break;
-        }
-        devpaths->devpaths_first = i;
-
-        return devpaths;
-
-read_error:
-        udev_err(udev_queue_export->udev, "queue file corrupted\n");
-        free(devpaths);
-        return NULL;
-}
-
-static int rebuild_queue_file(struct udev_queue_export *udev_queue_export)
-{
-        unsigned long long int seqnum;
-        struct queue_devpaths *devpaths = NULL;
-        FILE *new_queue_file = NULL;
-        unsigned int i;
-
-        /* read old queue file */
-        if (udev_queue_export->queue_file != NULL) {
-                devpaths = build_index(udev_queue_export);
-                if (devpaths != NULL)
-                        udev_queue_export->seqnum_max += devpaths->devpaths_first;
-        }
-        if (devpaths == NULL) {
-                udev_queue_export->queued_count = 0;
-                udev_queue_export->seqnum_max = udev_queue_export->seqnum_min;
-        }
-
-        /* create new queue file */
-        new_queue_file = fopen("/run/udev/queue.tmp", "w+e");
-        if (new_queue_file == NULL)
-                goto error;
-        seqnum = udev_queue_export->seqnum_max;
-        fwrite(&seqnum, 1, sizeof(unsigned long long int), new_queue_file);
-
-        /* copy unfinished events only to the new file */
-        if (devpaths != NULL) {
-                for (i = devpaths->devpaths_first; i < devpaths->devpaths_size; i++) {
-                        char devpath[UTIL_PATH_SIZE];
-                        int err;
-                        unsigned short devpath_len;
-
-                        if (devpaths->devpaths[i] != 0)
-                        {
-                                skip_to(udev_queue_export->queue_file, devpaths->devpaths[i]);
-                                err = udev_queue_read_devpath(udev_queue_export->queue_file, devpath, sizeof(devpath));
-                                devpath_len = err;
-
-                                fwrite(&seqnum, sizeof(unsigned long long int), 1, new_queue_file);
-                                fwrite(&devpath_len, sizeof(unsigned short), 1, new_queue_file);
-                                fwrite(devpath, 1, devpath_len, new_queue_file);
-                        }
-                        seqnum++;
-                }
-                free(devpaths);
-                devpaths = NULL;
-        }
-        fflush(new_queue_file);
-        if (ferror(new_queue_file))
-                goto error;
-
-        /* rename the new file on top of the old one */
-        if (rename("/run/udev/queue.tmp", "/run/udev/queue.bin") != 0)
-                goto error;
-
-        if (udev_queue_export->queue_file != NULL)
-                fclose(udev_queue_export->queue_file);
-        udev_queue_export->queue_file = new_queue_file;
-        udev_queue_export->waste_bytes = 0;
-
-        return 0;
-
-error:
-        udev_err(udev_queue_export->udev, "failed to create queue file: %m\n");
-        udev_queue_export_cleanup(udev_queue_export);
-
-        if (udev_queue_export->queue_file != NULL) {
-                fclose(udev_queue_export->queue_file);
-                udev_queue_export->queue_file = NULL;
-        }
-        if (new_queue_file != NULL)
-                fclose(new_queue_file);
-
-        if (devpaths != NULL)
-                free(devpaths);
-        udev_queue_export->queued_count = 0;
-        udev_queue_export->waste_bytes = 0;
-        udev_queue_export->seqnum_max = udev_queue_export->seqnum_min;
-
-        return -1;
-}
-
-static int write_queue_record(struct udev_queue_export *udev_queue_export,
-                              unsigned long long int seqnum, const char *devpath, size_t devpath_len)
-{
-        unsigned short len;
-
-        if (udev_queue_export->queue_file == NULL)
-                return -1;
-
-        if (fwrite(&seqnum, sizeof(unsigned long long int), 1, udev_queue_export->queue_file) != 1)
-                goto write_error;
-
-        len = (devpath_len < USHRT_MAX) ? devpath_len : USHRT_MAX;
-        if (fwrite(&len, sizeof(unsigned short), 1, udev_queue_export->queue_file) != 1)
-                goto write_error;
-        if (len > 0) {
-                if (fwrite(devpath, 1, len, udev_queue_export->queue_file) != len)
-                        goto write_error;
-        }
-
-        /* *must* flush output; caller may fork */
-        if (fflush(udev_queue_export->queue_file) != 0)
-                goto write_error;
-
-        return 0;
-
-write_error:
-        /* if we failed half way through writing a record to a file,
-           we should not try to write any further records to it. */
-        udev_err(udev_queue_export->udev, "error writing to queue file: %m\n");
-        fclose(udev_queue_export->queue_file);
-        udev_queue_export->queue_file = NULL;
-
-        return -1;
-}
-
-enum device_state {
-        DEVICE_QUEUED,
-        DEVICE_FINISHED,
-};
-
-static inline size_t queue_record_size(size_t devpath_len)
-{
-        return sizeof(unsigned long long int) + sizeof(unsigned short int) + devpath_len;
-}
-
-static int update_queue(struct udev_queue_export *udev_queue_export,
-                         struct udev_device *udev_device, enum device_state state)
-{
-        unsigned long long int seqnum = udev_device_get_seqnum(udev_device);
-        const char *devpath = NULL;
-        size_t devpath_len = 0;
-        int bytes;
-        int err;
-
-        /* FINISHED records have a zero length devpath */
-        if (state == DEVICE_QUEUED) {
-                devpath = udev_device_get_devpath(udev_device);
-                devpath_len = strlen(devpath);
-        }
-
-        /* recover from an earlier failed rebuild */
-        if (udev_queue_export->queue_file == NULL) {
-                if (rebuild_queue_file(udev_queue_export) != 0)
-                        return -1;
-        }
-
-        /* if we're removing the last event from the queue, that's the best time to rebuild it */
-        if (state != DEVICE_QUEUED && udev_queue_export->queued_count == 1) {
-                /* we don't need to read the old queue file */
-                fclose(udev_queue_export->queue_file);
-                udev_queue_export->queue_file = NULL;
-                rebuild_queue_file(udev_queue_export);
-                return 0;
-        }
-
-        /* try to rebuild the queue files before they grow larger than one page. */
-        bytes = ftell(udev_queue_export->queue_file) + queue_record_size(devpath_len);
-        if ((udev_queue_export->waste_bytes > bytes / 2) && bytes > 4096)
-                rebuild_queue_file(udev_queue_export);
-
-        /* don't record a finished event, if we already dropped the event in a failed rebuild */
-        if (seqnum < udev_queue_export->seqnum_max)
-                return 0;
-
-        /* now write to the queue */
-        if (state == DEVICE_QUEUED) {
-                udev_queue_export->queued_count++;
-                udev_queue_export->seqnum_min = seqnum;
-        } else {
-                udev_queue_export->waste_bytes += queue_record_size(devpath_len) + queue_record_size(0);
-                udev_queue_export->queued_count--;
-        }
-        err = write_queue_record(udev_queue_export, seqnum, devpath, devpath_len);
-
-        /* try to handle ENOSPC */
-        if (err != 0 && udev_queue_export->queued_count == 0) {
-                udev_queue_export_cleanup(udev_queue_export);
-                err = rebuild_queue_file(udev_queue_export);
-        }
-
-        return err;
-}
-
-static int update(struct udev_queue_export *udev_queue_export,
-                  struct udev_device *udev_device, enum device_state state)
-{
-        if (update_queue(udev_queue_export, udev_device, state) != 0)
-                return -1;
-
-        return 0;
-}
-
-int udev_queue_export_device_queued(struct udev_queue_export *udev_queue_export, struct udev_device *udev_device)
-{
-        return update(udev_queue_export, udev_device, DEVICE_QUEUED);
-}
-
-int udev_queue_export_device_finished(struct udev_queue_export *udev_queue_export, struct udev_device *udev_device)
-{
-        return update(udev_queue_export, udev_device, DEVICE_FINISHED);
-}
diff --git a/src/libudev/libudev-queue.c b/src/libudev/libudev-queue.c
index 2cb4d67121..eb0e096f84 100644
--- a/src/libudev/libudev-queue.c
+++ b/src/libudev/libudev-queue.c
@@ -24,8 +24,6 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
-#include <dirent.h>
-#include <fcntl.h>
 #include <limits.h>
 #include <sys/stat.h>
 
@@ -36,10 +34,7 @@
  * SECTION:libudev-queue
  * @short_description: access to currently active events
  *
- * The udev daemon processes events asynchronously. All events which do not have
- * interdependencies run in parallel. This exports the current state of the
- * event processing queue, and the current event sequence numbers from the kernel
- * and the udev daemon.
+ * This exports the current state of the udev processing queue.
  */
 
 /**
@@ -50,7 +45,6 @@
 struct udev_queue {
         struct udev *udev;
         int refcount;
-        struct udev_list queue_list;
 };
 
 /**
@@ -72,9 +66,9 @@ _public_ struct udev_queue *udev_queue_new(struct udev *udev)
         udev_queue = new0(struct udev_queue, 1);
         if (udev_queue == NULL)
                 return NULL;
+
         udev_queue->refcount = 1;
         udev_queue->udev = udev;
-        udev_list_init(udev, &udev_queue->queue_list, false);
         return udev_queue;
 }
 
@@ -90,6 +84,7 @@ _public_ struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue)
 {
         if (udev_queue == NULL)
                 return NULL;
+
         udev_queue->refcount++;
         return udev_queue;
 }
@@ -107,10 +102,11 @@ _public_ struct udev_queue *udev_queue_unref(struct udev_queue *udev_queue)
 {
         if (udev_queue == NULL)
                 return NULL;
+
         udev_queue->refcount--;
         if (udev_queue->refcount > 0)
                 return NULL;
-        udev_list_cleanup(&udev_queue->queue_list);
+
         free(udev_queue);
         return NULL;
 }
@@ -130,141 +126,30 @@ _public_ struct udev *udev_queue_get_udev(struct udev_queue *udev_queue)
         return udev_queue->udev;
 }
 
-unsigned long long int udev_get_kernel_seqnum(struct udev *udev)
-{
-        unsigned long long int seqnum;
-        int fd;
-        char buf[32];
-        ssize_t len;
-
-        fd = open("/sys/kernel/uevent_seqnum", O_RDONLY|O_CLOEXEC);
-        if (fd < 0)
-                return 0;
-        len = read(fd, buf, sizeof(buf));
-        close(fd);
-        if (len <= 2)
-                return 0;
-        buf[len-1] = '\0';
-        seqnum = strtoull(buf, NULL, 10);
-        return seqnum;
-}
-
 /**
  * udev_queue_get_kernel_seqnum:
  * @udev_queue: udev queue context
  *
- * Get the current kernel event sequence number.
+ * This function is deprecated.
  *
- * Returns: the sequence number.
+ * Returns: 0.
  **/
 _public_ unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue)
 {
-        unsigned long long int seqnum;
-
-        if (udev_queue == NULL)
-                return -EINVAL;
-
-        seqnum = udev_get_kernel_seqnum(udev_queue->udev);
-        return seqnum;
-}
-
-int udev_queue_read_seqnum(FILE *queue_file, unsigned long long int *seqnum)
-{
-        if (fread(seqnum, sizeof(unsigned long long int), 1, queue_file) != 1)
-                return -1;
-
         return 0;
 }
 
-ssize_t udev_queue_skip_devpath(FILE *queue_file)
-{
-        unsigned short int len;
-
-        if (fread(&len, sizeof(unsigned short int), 1, queue_file) == 1) {
-                char *devpath = alloca(len);
-
-                /* use fread to skip, fseek might drop buffered data */
-                if (fread(devpath, 1, len, queue_file) == len)
-                        return len;
-        }
-
-        return -1;
-}
-
-ssize_t udev_queue_read_devpath(FILE *queue_file, char *devpath, size_t size)
-{
-        unsigned short int read_bytes = 0;
-        unsigned short int len;
-
-        if (fread(&len, sizeof(unsigned short int), 1, queue_file) != 1)
-                return -1;
-
-        read_bytes = (len < size - 1) ? len : size - 1;
-        if (fread(devpath, 1, read_bytes, queue_file) != read_bytes)
-                return -1;
-        devpath[read_bytes] = '\0';
-
-        /* if devpath was too long, skip unread characters */
-        if (read_bytes != len) {
-                unsigned short int skip_bytes = len - read_bytes;
-                char *buf = alloca(skip_bytes);
-
-                if (fread(buf, 1, skip_bytes, queue_file) != skip_bytes)
-                        return -1;
-        }
-
-        return read_bytes;
-}
-
-static FILE *open_queue_file(struct udev_queue *udev_queue, unsigned long long int *seqnum_start)
-{
-        FILE *queue_file;
-
-        queue_file = fopen("/run/udev/queue.bin", "re");
-        if (queue_file == NULL)
-                return NULL;
-
-        if (udev_queue_read_seqnum(queue_file, seqnum_start) < 0) {
-                udev_err(udev_queue->udev, "corrupt queue file\n");
-                fclose(queue_file);
-                return NULL;
-        }
-
-        return queue_file;
-}
-
 /**
  * udev_queue_get_udev_seqnum:
  * @udev_queue: udev queue context
  *
- * Get the last known udev event sequence number.
+ * This function is deprecated.
  *
- * Returns: the sequence number.
+ * Returns: 0.
  **/
 _public_ unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue)
 {
-        unsigned long long int seqnum_udev;
-        FILE *queue_file;
-
-        queue_file = open_queue_file(udev_queue, &seqnum_udev);
-        if (queue_file == NULL)
-                return 0;
-
-        for (;;) {
-                unsigned long long int seqnum;
-                ssize_t devpath_len;
-
-                if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
-                        break;
-                devpath_len = udev_queue_skip_devpath(queue_file);
-                if (devpath_len < 0)
-                        break;
-                if (devpath_len > 0)
-                        seqnum_udev = seqnum;
-        }
-
-        fclose(queue_file);
-        return seqnum_udev;
+        return 0;
 }
 
 /**
@@ -277,15 +162,7 @@ _public_ unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *ud
  **/
 _public_ int udev_queue_get_udev_is_active(struct udev_queue *udev_queue)
 {
-        unsigned long long int seqnum_start;
-        FILE *queue_file;
-
-        queue_file = open_queue_file(udev_queue, &seqnum_start);
-        if (queue_file == NULL)
-                return 0;
-
-        fclose(queue_file);
-        return 1;
+        return access("/run/udev/control", F_OK) >= 0;
 }
 
 /**
@@ -298,48 +175,7 @@ _public_ int udev_queue_get_udev_is_active(struct udev_queue *udev_queue)
  **/
 _public_ int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue)
 {
-        unsigned long long int seqnum_kernel;
-        unsigned long long int seqnum_udev = 0;
-        int queued = 0;
-        int is_empty = 0;
-        FILE *queue_file;
-
-        if (udev_queue == NULL)
-                return -EINVAL;
-        queue_file = open_queue_file(udev_queue, &seqnum_udev);
-        if (queue_file == NULL)
-                return 1;
-
-        for (;;) {
-                unsigned long long int seqnum;
-                ssize_t devpath_len;
-
-                if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
-                        break;
-                devpath_len = udev_queue_skip_devpath(queue_file);
-                if (devpath_len < 0)
-                        break;
-
-                if (devpath_len > 0) {
-                        queued++;
-                        seqnum_udev = seqnum;
-                } else {
-                        queued--;
-                }
-        }
-
-        if (queued > 0)
-                goto out;
-
-        seqnum_kernel = udev_queue_get_kernel_seqnum(udev_queue);
-        if (seqnum_udev < seqnum_kernel)
-                goto out;
-
-        is_empty = 1;
-
-out:
-        fclose(queue_file);
-        return is_empty;
+        return access("/run/udev/queue", F_OK) >= 0;
 }
 
 /**
@@ -348,63 +184,15 @@ out:
  * @start: first event sequence number
  * @end: last event sequence number
  *
- * Check if udev is currently processing any events in a given sequence number range.
+ * This function is deprecated, it just returns the result of
+ * udev_queue_get_queue_is_empty().
  *
- * Returns: a flag indicating if any of the sequence numbers in the given range is currently active.
+ * Returns: a flag indicating if udev is currently handling events.
  **/
 _public_ int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_queue,
                                                unsigned long long int start, unsigned long long int end)
 {
-        unsigned long long int seqnum;
-        ssize_t devpath_len;
-        int unfinished;
-        FILE *queue_file;
-
-        if (udev_queue == NULL)
-                return -EINVAL;
-        queue_file = open_queue_file(udev_queue, &seqnum);
-        if (queue_file == NULL)
-                return 1;
-        if (start < seqnum)
-                start = seqnum;
-        if (start > end) {
-                fclose(queue_file);
-                return 1;
-        }
-        if (end - start > INT_MAX - 1) {
-                fclose(queue_file);
-                return -EOVERFLOW;
-        }
-
-        /*
-         * we might start with 0, and handle the initial seqnum
-         * only when we find an entry in the queue file
-         **/
-        unfinished = end - start;
-
-        do {
-                if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
-                        break;
-                devpath_len = udev_queue_skip_devpath(queue_file);
-                if (devpath_len < 0)
-                        break;
-
-                /*
-                 * we might start with an empty or re-build queue file, where
-                 * the initial seqnum is not recorded as finished
-                 */
-                if (start == seqnum && devpath_len > 0)
-                        unfinished++;
-
-                if (devpath_len == 0) {
-                        if (seqnum >= start && seqnum <= end)
-                                unfinished--;
-                }
-        } while (unfinished > 0);
-
-        fclose(queue_file);
-
-        return (unfinished == 0);
+        return udev_queue_get_queue_is_empty(udev_queue);
 }
 
 /**
@@ -412,69 +200,25 @@ _public_ int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_
  * @udev_queue: udev queue context
  * @seqnum: sequence number
  *
- * Check if udev is currently processing a given sequence number.
+ * This function is deprecated, it just returns the result of
+ * udev_queue_get_queue_is_empty().
  *
- * Returns: a flag indicating if the given sequence number is currently active.
+ * Returns: a flag indicating if udev is currently handling events.
  **/
 _public_ int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum)
 {
-        if (!udev_queue_get_seqnum_sequence_is_finished(udev_queue, seqnum, seqnum))
-                return 0;
-
-        return 1;
+        return udev_queue_get_queue_is_empty(udev_queue);
 }
 
 /**
  * udev_queue_get_queued_list_entry:
  * @udev_queue: udev queue context
  *
- * Get the first entry of the list of queued events.
+ * This function is deprecated.
  *
- * Returns: a udev_list_entry.
+ * Returns: NULL.
  **/
 _public_ struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue)
 {
-        unsigned long long int seqnum;
-        FILE *queue_file;
-
-        if (udev_queue == NULL)
-                return NULL;
-        udev_list_cleanup(&udev_queue->queue_list);
-
-        queue_file = open_queue_file(udev_queue, &seqnum);
-        if (queue_file == NULL)
-                return NULL;
-
-        for (;;) {
-                char syspath[UTIL_PATH_SIZE];
-                char *s;
-                size_t l;
-                ssize_t len;
-                char seqnum_str[32];
-                struct udev_list_entry *list_entry;
-
-                if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
-                        break;
-                snprintf(seqnum_str, sizeof(seqnum_str), "%llu", seqnum);
-
-                s = syspath;
-                l = strpcpy(&s, sizeof(syspath), "/sys");
-                len = udev_queue_read_devpath(queue_file, s, l);
-                if (len < 0)
-                        break;
-
-                if (len > 0) {
-                        udev_list_entry_add(&udev_queue->queue_list, syspath, seqnum_str);
-                } else {
-                        udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_queue->queue_list)) {
-                                if (streq(seqnum_str, udev_list_entry_get_value(list_entry))) {
-                                        udev_list_entry_delete(list_entry);
-                                        break;
-                                }
-                        }
-                }
-        }
-        fclose(queue_file);
-
-        return udev_list_get_entry(&udev_queue->queue_list);
+        return NULL;
 }
diff --git a/src/libudev/libudev.h b/src/libudev/libudev.h
index b9b8f13e44..ceb89bd593 100644
--- a/src/libudev/libudev.h
+++ b/src/libudev/libudev.h
@@ -170,14 +170,14 @@ struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue);
 struct udev_queue *udev_queue_unref(struct udev_queue *udev_queue);
 struct udev *udev_queue_get_udev(struct udev_queue *udev_queue);
 struct udev_queue *udev_queue_new(struct udev *udev);
-unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue);
-unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue);
+unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue) __attribute__ ((deprecated));
+unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue) __attribute__ ((deprecated));
 int udev_queue_get_udev_is_active(struct udev_queue *udev_queue);
 int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue);
-int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum);
+int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum) __attribute__ ((deprecated));
 int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_queue,
-                                               unsigned long long int start, unsigned long long int end);
-struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue);
+                                               unsigned long long int start, unsigned long long int end) __attribute__ ((deprecated));
+struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue) __attribute__ ((deprecated));
 
 /*
  *  udev_hwdb