Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 5292 insertions, 0 deletions

diff --git a/src/libsystemd/sd-device/device-enumerator-private.h b/src/libsystemd/sd-device/device-enumerator-private.h
new file mode 100644
index 0000000..87411bf
--- /dev/null
+++ b/src/libsystemd/sd-device/device-enumerator-private.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "sd-device.h"
+
+int device_enumerator_scan_devices(sd_device_enumerator *enumeartor);
+int device_enumerator_scan_subsystems(sd_device_enumerator *enumeartor);
+int device_enumerator_add_device(sd_device_enumerator *enumerator, sd_device *device);
+int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator);
+sd_device *device_enumerator_get_first(sd_device_enumerator *enumerator);
+sd_device *device_enumerator_get_next(sd_device_enumerator *enumerator);
+sd_device **device_enumerator_get_devices(sd_device_enumerator *enumerator, size_t *ret_n_devices);
+
+#define FOREACH_DEVICE_AND_SUBSYSTEM(enumerator, device)       \
+        for (device = device_enumerator_get_first(enumerator); \
+             device;                                           \
+             device = device_enumerator_get_next(enumerator))
diff --git a/src/libsystemd/sd-device/device-enumerator.c b/src/libsystemd/sd-device/device-enumerator.c
new file mode 100644
index 0000000..20529aa
--- /dev/null
+++ b/src/libsystemd/sd-device/device-enumerator.c
@@ -0,0 +1,1004 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-enumerator-private.h"
+#include "device-util.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "set.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+#define DEVICE_ENUMERATE_MAX_DEPTH 256
+
+typedef enum DeviceEnumerationType {
+        DEVICE_ENUMERATION_TYPE_DEVICES,
+        DEVICE_ENUMERATION_TYPE_SUBSYSTEMS,
+        _DEVICE_ENUMERATION_TYPE_MAX,
+        _DEVICE_ENUMERATION_TYPE_INVALID = -1,
+} DeviceEnumerationType;
+
+struct sd_device_enumerator {
+        unsigned n_ref;
+
+        DeviceEnumerationType type;
+        sd_device **devices;
+        size_t n_devices, n_allocated, current_device_index;
+        bool scan_uptodate;
+
+        Set *match_subsystem;
+        Set *nomatch_subsystem;
+        Hashmap *match_sysattr;
+        Hashmap *nomatch_sysattr;
+        Hashmap *match_property;
+        Set *match_sysname;
+        Set *match_tag;
+        sd_device *match_parent;
+        bool match_allow_uninitialized;
+};
+
+_public_ int sd_device_enumerator_new(sd_device_enumerator **ret) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *enumerator = NULL;
+
+        assert(ret);
+
+        enumerator = new(sd_device_enumerator, 1);
+        if (!enumerator)
+                return -ENOMEM;
+
+        *enumerator = (sd_device_enumerator) {
+                .n_ref = 1,
+                .type = _DEVICE_ENUMERATION_TYPE_INVALID,
+        };
+
+        *ret = TAKE_PTR(enumerator);
+
+        return 0;
+}
+
+static sd_device_enumerator *device_enumerator_free(sd_device_enumerator *enumerator) {
+        size_t i;
+
+        assert(enumerator);
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        free(enumerator->devices);
+        set_free_free(enumerator->match_subsystem);
+        set_free_free(enumerator->nomatch_subsystem);
+        hashmap_free_free_free(enumerator->match_sysattr);
+        hashmap_free_free_free(enumerator->nomatch_sysattr);
+        hashmap_free_free_free(enumerator->match_property);
+        set_free_free(enumerator->match_sysname);
+        set_free_free(enumerator->match_tag);
+        sd_device_unref(enumerator->match_parent);
+
+        return mfree(enumerator);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_enumerator, sd_device_enumerator, device_enumerator_free);
+
+_public_ int sd_device_enumerator_add_match_subsystem(sd_device_enumerator *enumerator, const char *subsystem, int match) {
+        Set **set;
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        if (match)
+                set = &enumerator->match_subsystem;
+        else
+                set = &enumerator->nomatch_subsystem;
+
+        r = set_ensure_allocated(set, NULL);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(*set, subsystem);
+        if (r < 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_add_match_sysattr(sd_device_enumerator *enumerator, const char *_sysattr, const char *_value, int match) {
+        _cleanup_free_ char *sysattr = NULL, *value = NULL;
+        Hashmap **hashmap;
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(_sysattr, -EINVAL);
+
+        if (match)
+                hashmap = &enumerator->match_sysattr;
+        else
+                hashmap = &enumerator->nomatch_sysattr;
+
+        r = hashmap_ensure_allocated(hashmap, NULL);
+        if (r < 0)
+                return r;
+
+        sysattr = strdup(_sysattr);
+        if (!sysattr)
+                return -ENOMEM;
+
+        if (_value) {
+                value = strdup(_value);
+                if (!value)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_put(*hashmap, sysattr, value);
+        if (r < 0)
+                return r;
+
+        sysattr = NULL;
+        value = NULL;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_add_match_property(sd_device_enumerator *enumerator, const char *_property, const char *_value) {
+        _cleanup_free_ char *property = NULL, *value = NULL;
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(_property, -EINVAL);
+
+        r = hashmap_ensure_allocated(&enumerator->match_property, NULL);
+        if (r < 0)
+                return r;
+
+        property = strdup(_property);
+        if (!property)
+                return -ENOMEM;
+
+        if (_value) {
+                value = strdup(_value);
+                if (!value)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_put(enumerator->match_property, property, value);
+        if (r < 0)
+                return r;
+
+        property = NULL;
+        value = NULL;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_add_match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(sysname, -EINVAL);
+
+        r = set_ensure_allocated(&enumerator->match_sysname, NULL);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(enumerator->match_sysname, sysname);
+        if (r < 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_add_match_tag(sd_device_enumerator *enumerator, const char *tag) {
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        r = set_ensure_allocated(&enumerator->match_tag, NULL);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(enumerator->match_tag, tag);
+        if (r < 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_add_match_parent(sd_device_enumerator *enumerator, sd_device *parent) {
+        assert_return(enumerator, -EINVAL);
+        assert_return(parent, -EINVAL);
+
+        sd_device_unref(enumerator->match_parent);
+        enumerator->match_parent = sd_device_ref(parent);
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_enumerator_allow_uninitialized(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, -EINVAL);
+
+        enumerator->match_allow_uninitialized = true;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, -EINVAL);
+
+        enumerator->match_allow_uninitialized = false;
+
+        enumerator->scan_uptodate = false;
+
+        return 0;
+}
+
+static int device_compare(sd_device * const *_a, sd_device * const *_b) {
+        sd_device *a = *(sd_device **)_a, *b = *(sd_device **)_b;
+        const char *devpath_a, *devpath_b, *sound_a;
+        bool delay_a, delay_b;
+        int r;
+
+        assert_se(sd_device_get_devpath(a, &devpath_a) >= 0);
+        assert_se(sd_device_get_devpath(b, &devpath_b) >= 0);
+
+        sound_a = strstr(devpath_a, "/sound/card");
+        if (sound_a) {
+                /* For sound cards the control device must be enumerated last to
+                 * make sure it's the final device node that gets ACLs applied.
+                 * Applications rely on this fact and use ACL changes on the
+                 * control node as an indicator that the ACL change of the
+                 * entire sound card completed. The kernel makes this guarantee
+                 * when creating those devices, and hence we should too when
+                 * enumerating them. */
+                sound_a += STRLEN("/sound/card");
+                sound_a = strchr(sound_a, '/');
+
+                if (sound_a) {
+                        unsigned prefix_len;
+
+                        prefix_len = sound_a - devpath_a;
+
+                        if (strncmp(devpath_a, devpath_b, prefix_len) == 0) {
+                                const char *sound_b;
+
+                                sound_b = devpath_b + prefix_len;
+
+                                if (startswith(sound_a, "/controlC") &&
+                                    !startswith(sound_b, "/contolC"))
+                                        return 1;
+
+                                if (!startswith(sound_a, "/controlC") &&
+                                    startswith(sound_b, "/controlC"))
+                                        return -1;
+                        }
+                }
+        }
+
+        /* md and dm devices are enumerated after all other devices */
+        delay_a = strstr(devpath_a, "/block/md") || strstr(devpath_a, "/block/dm-");
+        delay_b = strstr(devpath_b, "/block/md") || strstr(devpath_b, "/block/dm-");
+        r = CMP(delay_a, delay_b);
+        if (r != 0)
+                return r;
+
+        return strcmp(devpath_a, devpath_b);
+}
+
+int device_enumerator_add_device(sd_device_enumerator *enumerator, sd_device *device) {
+        assert_return(enumerator, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        if (!GREEDY_REALLOC(enumerator->devices, enumerator->n_allocated, enumerator->n_devices + 1))
+                return -ENOMEM;
+
+        enumerator->devices[enumerator->n_devices++] = sd_device_ref(device);
+
+        return 0;
+}
+
+static bool match_sysattr_value(sd_device *device, const char *sysattr, const char *match_value) {
+        const char *value;
+        int r;
+
+        assert(device);
+        assert(sysattr);
+
+        r = sd_device_get_sysattr_value(device, sysattr, &value);
+        if (r < 0)
+                return false;
+
+        if (!match_value)
+                return true;
+
+        if (fnmatch(match_value, value, 0) == 0)
+                return true;
+
+        return false;
+}
+
+static bool match_sysattr(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *sysattr;
+        const char *value;
+        Iterator i;
+
+        assert(enumerator);
+        assert(device);
+
+        HASHMAP_FOREACH_KEY(value, sysattr, enumerator->nomatch_sysattr, i)
+                if (match_sysattr_value(device, sysattr, value))
+                        return false;
+
+        HASHMAP_FOREACH_KEY(value, sysattr, enumerator->match_sysattr, i)
+                if (!match_sysattr_value(device, sysattr, value))
+                        return false;
+
+        return true;
+}
+
+static bool match_property(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *property;
+        const char *value;
+        Iterator i;
+
+        assert(enumerator);
+        assert(device);
+
+        if (hashmap_isempty(enumerator->match_property))
+                return true;
+
+        HASHMAP_FOREACH_KEY(value, property, enumerator->match_property, i) {
+                const char *property_dev, *value_dev;
+
+                FOREACH_DEVICE_PROPERTY(device, property_dev, value_dev) {
+                        if (fnmatch(property, property_dev, 0) != 0)
+                                continue;
+
+                        if (!value && !value_dev)
+                                return true;
+
+                        if (!value || !value_dev)
+                                continue;
+
+                        if (fnmatch(value, value_dev, 0) == 0)
+                                return true;
+                }
+        }
+
+        return false;
+}
+
+static bool match_tag(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *tag;
+        Iterator i;
+
+        assert(enumerator);
+        assert(device);
+
+        SET_FOREACH(tag, enumerator->match_tag, i)
+                if (!sd_device_has_tag(device, tag))
+                        return false;
+
+        return true;
+}
+
+static bool match_parent(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *devpath, *devpath_dev;
+        int r;
+
+        assert(enumerator);
+        assert(device);
+
+        if (!enumerator->match_parent)
+                return true;
+
+        r = sd_device_get_devpath(enumerator->match_parent, &devpath);
+        assert(r >= 0);
+
+        r = sd_device_get_devpath(device, &devpath_dev);
+        assert(r >= 0);
+
+        return startswith(devpath_dev, devpath);
+}
+
+static bool match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
+        const char *sysname_match;
+        Iterator i;
+
+        assert(enumerator);
+        assert(sysname);
+
+        if (set_isempty(enumerator->match_sysname))
+                return true;
+
+        SET_FOREACH(sysname_match, enumerator->match_sysname, i)
+                if (fnmatch(sysname_match, sysname, 0) == 0)
+                        return true;
+
+        return false;
+}
+
+static int enumerator_scan_dir_and_add_devices(sd_device_enumerator *enumerator, const char *basedir, const char *subdir1, const char *subdir2) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        assert(enumerator);
+        assert(basedir);
+
+        path = strjoina("/sys/", basedir, "/");
+
+        if (subdir1)
+                path = strjoina(path, subdir1, "/");
+
+        if (subdir2)
+                path = strjoina(path, subdir2, "/");
+
+        dir = opendir(path);
+        if (!dir)
+                return -errno;
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                char syspath[strlen(path) + 1 + strlen(dent->d_name) + 1];
+                int initialized, k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (!match_sysname(enumerator, dent->d_name))
+                        continue;
+
+                (void) sprintf(syspath, "%s%s", path, dent->d_name);
+
+                k = sd_device_new_from_syspath(&device, syspath);
+                if (k < 0) {
+                        if (k != -ENODEV)
+                                /* this is necessarily racey, so ignore missing devices */
+                                r = k;
+
+                        continue;
+                }
+
+                initialized = sd_device_get_is_initialized(device);
+                if (initialized < 0) {
+                        r = initialized;
+                        continue;
+                }
+
+                /*
+                 * All devices with a device node or network interfaces
+                 * possibly need udev to adjust the device node permission
+                 * or context, or rename the interface before it can be
+                 * reliably used from other processes.
+                 *
+                 * For now, we can only check these types of devices, we
+                 * might not store a database, and have no way to find out
+                 * for all other types of devices.
+                 */
+                if (!enumerator->match_allow_uninitialized &&
+                    !initialized &&
+                    (sd_device_get_devnum(device, NULL) >= 0 ||
+                     sd_device_get_ifindex(device, NULL) >= 0))
+                        continue;
+
+                if (!match_parent(enumerator, device))
+                        continue;
+
+                if (!match_tag(enumerator, device))
+                        continue;
+
+                if (!match_property(enumerator, device))
+                        continue;
+
+                if (!match_sysattr(enumerator, device))
+                        continue;
+
+                k = device_enumerator_add_device(enumerator, device);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static bool match_subsystem(sd_device_enumerator *enumerator, const char *subsystem) {
+        const char *subsystem_match;
+        Iterator i;
+
+        assert(enumerator);
+
+        if (!subsystem)
+                return false;
+
+        SET_FOREACH(subsystem_match, enumerator->nomatch_subsystem, i)
+                if (fnmatch(subsystem_match, subsystem, 0) == 0)
+                        return false;
+
+        if (set_isempty(enumerator->match_subsystem))
+                return true;
+
+        SET_FOREACH(subsystem_match, enumerator->match_subsystem, i)
+                if (fnmatch(subsystem_match, subsystem, 0) == 0)
+                        return true;
+
+        return false;
+}
+
+static int enumerator_scan_dir(sd_device_enumerator *enumerator, const char *basedir, const char *subdir, const char *subsystem) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        path = strjoina("/sys/", basedir);
+
+        dir = opendir(path);
+        if (!dir)
+                return -errno;
+
+        log_debug("sd-device-enumerator: Scanning %s", path);
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (!match_subsystem(enumerator, subsystem ? : dent->d_name))
+                        continue;
+
+                k = enumerator_scan_dir_and_add_devices(enumerator, basedir, dent->d_name, subdir);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_tag(sd_device_enumerator *enumerator, const char *tag) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        assert(enumerator);
+        assert(tag);
+
+        path = strjoina("/run/udev/tags/", tag);
+
+        dir = opendir(path);
+        if (!dir) {
+                if (errno != ENOENT)
+                        return log_debug_errno(errno, "sd-device-enumerator: Failed to open tags directory %s: %m", path);
+                return 0;
+        }
+
+        /* TODO: filter away subsystems? */
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                const char *subsystem, *sysname;
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                k = sd_device_new_from_device_id(&device, dent->d_name);
+                if (k < 0) {
+                        if (k != -ENODEV)
+                                /* this is necessarily racy, so ignore missing devices */
+                                r = k;
+
+                        continue;
+                }
+
+                k = sd_device_get_subsystem(device, &subsystem);
+                if (k < 0) {
+                        r = k;
+                        continue;
+                }
+
+                if (!match_subsystem(enumerator, subsystem))
+                        continue;
+
+                k = sd_device_get_sysname(device, &sysname);
+                if (k < 0) {
+                        r = k;
+                        continue;
+                }
+
+                if (!match_sysname(enumerator, sysname))
+                        continue;
+
+                if (!match_parent(enumerator, device))
+                        continue;
+
+                if (!match_property(enumerator, device))
+                        continue;
+
+                if (!match_sysattr(enumerator, device))
+                        continue;
+
+                k = device_enumerator_add_device(enumerator, device);
+                if (k < 0) {
+                        r = k;
+                        continue;
+                }
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_tags(sd_device_enumerator *enumerator) {
+        const char *tag;
+        Iterator i;
+        int r = 0;
+
+        assert(enumerator);
+
+        SET_FOREACH(tag, enumerator->match_tag, i) {
+                int k;
+
+                k = enumerator_scan_devices_tag(enumerator, tag);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int parent_add_child(sd_device_enumerator *enumerator, const char *path) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        const char *subsystem, *sysname;
+        int r;
+
+        r = sd_device_new_from_syspath(&device, path);
+        if (r == -ENODEV)
+                /* this is necessarily racy, so ignore missing devices */
+                return 0;
+        else if (r < 0)
+                return r;
+
+        r = sd_device_get_subsystem(device, &subsystem);
+        if (r == -ENOENT)
+                return 0;
+        if (r < 0)
+                return r;
+
+        if (!match_subsystem(enumerator, subsystem))
+                return 0;
+
+        r = sd_device_get_sysname(device, &sysname);
+        if (r < 0)
+                return r;
+
+        if (!match_sysname(enumerator, sysname))
+                return 0;
+
+        if (!match_property(enumerator, device))
+                return 0;
+
+        if (!match_sysattr(enumerator, device))
+                return 0;
+
+        r = device_enumerator_add_device(enumerator, device);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int parent_crawl_children(sd_device_enumerator *enumerator, const char *path, unsigned maxdepth) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        struct dirent *dent;
+        int r = 0;
+
+        dir = opendir(path);
+        if (!dir)
+                return log_debug_errno(errno, "sd-device-enumerator: Failed to open parent directory %s: %m", path);
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_free_ char *child = NULL;
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (dent->d_type != DT_DIR)
+                        continue;
+
+                child = strjoin(path, "/", dent->d_name);
+                if (!child)
+                        return -ENOMEM;
+
+                k = parent_add_child(enumerator, child);
+                if (k < 0)
+                        r = k;
+
+                if (maxdepth > 0)
+                        parent_crawl_children(enumerator, child, maxdepth - 1);
+                else
+                        log_debug("sd-device-enumerator: Max depth reached, %s: ignoring devices", child);
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_children(sd_device_enumerator *enumerator) {
+        const char *path;
+        int r = 0, k;
+
+        r = sd_device_get_syspath(enumerator->match_parent, &path);
+        if (r < 0)
+                return r;
+
+        k = parent_add_child(enumerator, path);
+        if (k < 0)
+                r = k;
+
+        k = parent_crawl_children(enumerator, path, DEVICE_ENUMERATE_MAX_DEPTH);
+        if (k < 0)
+                r = k;
+
+        return r;
+}
+
+static int enumerator_scan_devices_all(sd_device_enumerator *enumerator) {
+        int r = 0;
+
+        log_debug("sd-device-enumerator: Scan all dirs");
+
+        if (access("/sys/subsystem", F_OK) >= 0) {
+                /* we have /subsystem/, forget all the old stuff */
+                r = enumerator_scan_dir(enumerator, "subsystem", "devices", NULL);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-enumerator: Failed to scan /sys/subsystem: %m");
+        } else {
+                int k;
+
+                k = enumerator_scan_dir(enumerator, "bus", "devices", NULL);
+                if (k < 0) {
+                        log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/bus: %m");
+                        r = k;
+                }
+
+                k = enumerator_scan_dir(enumerator, "class", NULL, NULL);
+                if (k < 0) {
+                        log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/class: %m");
+                        r = k;
+                }
+        }
+
+        return r;
+}
+
+static void device_enumerator_dedup_devices(sd_device_enumerator *enumerator) {
+        sd_device **a, **b, **end;
+
+        assert(enumerator);
+
+        if (enumerator->n_devices <= 1)
+                return;
+
+        a = enumerator->devices + 1;
+        b = enumerator->devices;
+        end = enumerator->devices + enumerator->n_devices;
+
+        for (; a < end; a++) {
+                const char *devpath_a, *devpath_b;
+
+                assert_se(sd_device_get_devpath(*a, &devpath_a) >= 0);
+                assert_se(sd_device_get_devpath(*b, &devpath_b) >= 0);
+
+                if (path_equal(devpath_a, devpath_b))
+                        sd_device_unref(*a);
+                else
+                        *(++b) = *a;
+        }
+
+        enumerator->n_devices = b - enumerator->devices + 1;
+}
+
+int device_enumerator_scan_devices(sd_device_enumerator *enumerator) {
+        int r = 0, k;
+        size_t i;
+
+        assert(enumerator);
+
+        if (enumerator->scan_uptodate &&
+            enumerator->type == DEVICE_ENUMERATION_TYPE_DEVICES)
+                return 0;
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        enumerator->n_devices = 0;
+
+        if (!set_isempty(enumerator->match_tag)) {
+                k = enumerator_scan_devices_tags(enumerator);
+                if (k < 0)
+                        r = k;
+        } else if (enumerator->match_parent) {
+                k = enumerator_scan_devices_children(enumerator);
+                if (k < 0)
+                        r = k;
+        } else {
+                k = enumerator_scan_devices_all(enumerator);
+                if (k < 0)
+                        r = k;
+        }
+
+        typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
+
+        enumerator->scan_uptodate = true;
+        enumerator->type = DEVICE_ENUMERATION_TYPE_DEVICES;
+
+        return r;
+}
+
+_public_ sd_device *sd_device_enumerator_get_device_first(sd_device_enumerator *enumerator) {
+        int r;
+
+        assert_return(enumerator, NULL);
+
+        r = device_enumerator_scan_devices(enumerator);
+        if (r < 0)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+_public_ sd_device *sd_device_enumerator_get_device_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->type != DEVICE_ENUMERATION_TYPE_DEVICES ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+int device_enumerator_scan_subsystems(sd_device_enumerator *enumerator) {
+        const char *subsysdir;
+        int r = 0, k;
+        size_t i;
+
+        assert(enumerator);
+
+        if (enumerator->scan_uptodate &&
+            enumerator->type == DEVICE_ENUMERATION_TYPE_SUBSYSTEMS)
+                return 0;
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        enumerator->n_devices = 0;
+
+        /* modules */
+        if (match_subsystem(enumerator, "module")) {
+                k = enumerator_scan_dir_and_add_devices(enumerator, "module", NULL, NULL);
+                if (k < 0) {
+                        log_debug_errno(k, "sd-device-enumerator: Failed to scan modules: %m");
+                        r = k;
+                }
+        }
+
+        if (access("/sys/subsystem", F_OK) >= 0)
+                subsysdir = "subsystem";
+        else
+                subsysdir = "bus";
+
+        /* subsystems (only buses support coldplug) */
+        if (match_subsystem(enumerator, "subsystem")) {
+                k = enumerator_scan_dir_and_add_devices(enumerator, subsysdir, NULL, NULL);
+                if (k < 0) {
+                        log_debug_errno(k, "sd-device-enumerator: Failed to scan subsystems: %m");
+                        r = k;
+                }
+        }
+
+        /* subsystem drivers */
+        if (match_subsystem(enumerator, "drivers")) {
+                k = enumerator_scan_dir(enumerator, subsysdir, "drivers", "drivers");
+                if (k < 0) {
+                        log_debug_errno(k, "sd-device-enumerator: Failed to scan drivers: %m");
+                        r = k;
+                }
+        }
+
+        typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
+
+        enumerator->scan_uptodate = true;
+        enumerator->type = DEVICE_ENUMERATION_TYPE_SUBSYSTEMS;
+
+        return r;
+}
+
+_public_ sd_device *sd_device_enumerator_get_subsystem_first(sd_device_enumerator *enumerator) {
+        int r;
+
+        assert_return(enumerator, NULL);
+
+        r = device_enumerator_scan_subsystems(enumerator);
+        if (r < 0)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+_public_ sd_device *sd_device_enumerator_get_subsystem_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->type != DEVICE_ENUMERATION_TYPE_SUBSYSTEMS ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+sd_device *device_enumerator_get_first(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+sd_device *device_enumerator_get_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+sd_device **device_enumerator_get_devices(sd_device_enumerator *enumerator, size_t *ret_n_devices) {
+        assert(enumerator);
+        assert(ret_n_devices);
+
+        if (!enumerator->scan_uptodate)
+                return NULL;
+
+        *ret_n_devices = enumerator->n_devices;
+        return enumerator->devices;
+}
diff --git a/src/libsystemd/sd-device/device-internal.h b/src/libsystemd/sd-device/device-internal.h
new file mode 100644
index 0000000..3ffca35
--- /dev/null
+++ b/src/libsystemd/sd-device/device-internal.h
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "sd-device.h"
+
+#include "hashmap.h"
+#include "set.h"
+#include "time-util.h"
+
+struct sd_device {
+        unsigned n_ref;
+
+        int watch_handle;
+
+        sd_device *parent;
+
+        OrderedHashmap *properties;
+        Iterator properties_iterator;
+        uint64_t properties_generation; /* changes whenever the properties are changed */
+        uint64_t properties_iterator_generation; /* generation when iteration was started */
+
+        /* the subset of the properties that should be written to the db */
+        OrderedHashmap *properties_db;
+
+        Hashmap *sysattr_values; /* cached sysattr values */
+
+        Set *sysattrs; /* names of sysattrs */
+        Iterator sysattrs_iterator;
+
+        Set *tags;
+        Iterator tags_iterator;
+        uint64_t tags_generation; /* changes whenever the tags are changed */
+        uint64_t tags_iterator_generation; /* generation when iteration was started */
+
+        Set *devlinks;
+        Iterator devlinks_iterator;
+        uint64_t devlinks_generation; /* changes whenever the devlinks are changed */
+        uint64_t devlinks_iterator_generation; /* generation when iteration was started */
+        int devlink_priority;
+
+        int ifindex;
+        char *devtype;
+        char *devname;
+        dev_t devnum;
+
+        char **properties_strv; /* the properties hashmap as a strv */
+        uint8_t *properties_nulstr; /* the same as a nulstr */
+        size_t properties_nulstr_len;
+
+        char *syspath;
+        const char *devpath;
+        const char *sysnum;
+        char *sysname;
+
+        char *subsystem;
+        char *driver_subsystem; /* only set for the 'drivers' subsystem */
+        char *driver;
+
+        char *id_filename;
+
+        uint64_t usec_initialized;
+
+        mode_t devmode;
+        uid_t devuid;
+        gid_t devgid;
+
+        bool parent_set:1; /* no need to try to reload parent */
+        bool sysattrs_read:1; /* don't try to re-read sysattrs once read */
+        bool property_tags_outdated:1; /* need to update TAGS= property */
+        bool property_devlinks_outdated:1; /* need to update DEVLINKS= property */
+        bool properties_buf_outdated:1; /* need to reread hashmap */
+        bool sysname_set:1; /* don't reread sysname */
+        bool subsystem_set:1; /* don't reread subsystem */
+        bool driver_subsystem_set:1; /* don't reread subsystem */
+        bool driver_set:1; /* don't reread driver */
+        bool uevent_loaded:1; /* don't reread uevent */
+        bool db_loaded; /* don't reread db */
+
+        bool is_initialized:1;
+        bool sealed:1; /* don't read more information from uevent/db */
+        bool db_persist:1; /* don't clean up the db when switching from initrd to real root */
+};
+
+typedef enum DeviceAction {
+        DEVICE_ACTION_ADD,
+        DEVICE_ACTION_REMOVE,
+        DEVICE_ACTION_CHANGE,
+        DEVICE_ACTION_MOVE,
+        DEVICE_ACTION_ONLINE,
+        DEVICE_ACTION_OFFLINE,
+        DEVICE_ACTION_BIND,
+        DEVICE_ACTION_UNBIND,
+        _DEVICE_ACTION_MAX,
+        _DEVICE_ACTION_INVALID = -1,
+} DeviceAction;
+
+int device_new_aux(sd_device **ret);
+int device_add_property_aux(sd_device *device, const char *key, const char *value, bool db);
+int device_add_property_internal(sd_device *device, const char *key, const char *value);
+int device_read_uevent_file(sd_device *device);
+
+int device_set_syspath(sd_device *device, const char *_syspath, bool verify);
+int device_set_ifindex(sd_device *device, const char *ifindex);
+int device_set_devmode(sd_device *device, const char *devmode);
+int device_set_devname(sd_device *device, const char *_devname);
+int device_set_devtype(sd_device *device, const char *_devtype);
+int device_set_devnum(sd_device *device, const char *major, const char *minor);
+int device_set_subsystem(sd_device *device, const char *_subsystem);
+int device_set_driver(sd_device *device, const char *_driver);
+int device_set_usec_initialized(sd_device *device, usec_t when);
+
+DeviceAction device_action_from_string(const char *s) _pure_;
+const char *device_action_to_string(DeviceAction a) _const_;
diff --git a/src/libsystemd/sd-device/device-monitor-private.h b/src/libsystemd/sd-device/device-monitor-private.h
new file mode 100644
index 0000000..2659cc3
--- /dev/null
+++ b/src/libsystemd/sd-device/device-monitor-private.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "sd-device.h"
+
+typedef enum MonitorNetlinkGroup {
+        MONITOR_GROUP_NONE,
+        MONITOR_GROUP_KERNEL,
+        MONITOR_GROUP_UDEV,
+        _MONITOR_NETLINK_GROUP_MAX,
+        _MONITOR_NETLINK_GROUP_INVALID = -1,
+} MonitorNetlinkGroup;
+
+int device_monitor_new_full(sd_device_monitor **ret, MonitorNetlinkGroup group, int fd);
+int device_monitor_disconnect(sd_device_monitor *m);
+int device_monitor_allow_unicast_sender(sd_device_monitor *m, sd_device_monitor *sender);
+int device_monitor_enable_receiving(sd_device_monitor *m);
+int device_monitor_get_fd(sd_device_monitor *m);
+int device_monitor_send_device(sd_device_monitor *m, sd_device_monitor *destination, sd_device *device);
+int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret);
diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
new file mode 100644
index 0000000..27d0af5
--- /dev/null
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -0,0 +1,756 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <linux/filter.h>
+#include <linux/netlink.h>
+#include <sys/socket.h>
+
+#include "sd-device.h"
+#include "sd-event.h"
+
+#include "MurmurHash2.h"
+#include "alloc-util.h"
+#include "device-monitor-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "hashmap.h"
+#include "io-util.h"
+#include "missing.h"
+#include "mountpoint-util.h"
+#include "set.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+struct sd_device_monitor {
+        unsigned n_ref;
+
+        int sock;
+        union sockaddr_union snl;
+        union sockaddr_union snl_trusted_sender;
+        bool bound;
+
+        Hashmap *subsystem_filter;
+        Set *tag_filter;
+        bool filter_uptodate;
+
+        sd_event *event;
+        sd_event_source *event_source;
+        sd_device_monitor_handler_t callback;
+        void *userdata;
+};
+
+#define UDEV_MONITOR_MAGIC                0xfeedcafe
+
+typedef struct monitor_netlink_header {
+        /* "libudev" prefix to distinguish libudev and kernel messages */
+        char prefix[8];
+        /* Magic to protect against daemon <-> Library message format mismatch
+         * Used in the kernel from socket filter rules; needs to be stored in network order */
+        unsigned magic;
+        /* Total length of header structure known to the sender */
+        unsigned header_size;
+        /* Properties string buffer */
+        unsigned properties_off;
+        unsigned properties_len;
+        /* Hashes of primary device properties strings, to let libudev subscribers
+         * use in-kernel socket filters; values need to be stored in network order */
+        unsigned filter_subsystem_hash;
+        unsigned filter_devtype_hash;
+        unsigned filter_tag_bloom_hi;
+        unsigned filter_tag_bloom_lo;
+} monitor_netlink_header;
+
+static int monitor_set_nl_address(sd_device_monitor *m) {
+        union sockaddr_union snl;
+        socklen_t addrlen;
+
+        assert(m);
+
+        /* Get the address the kernel has assigned us.
+         * It is usually, but not necessarily the pid. */
+        addrlen = sizeof(struct sockaddr_nl);
+        if (getsockname(m->sock, &snl.sa, &addrlen) < 0)
+                return -errno;
+
+        m->snl.nl.nl_pid = snl.nl.nl_pid;
+        return 0;
+}
+
+int device_monitor_allow_unicast_sender(sd_device_monitor *m, sd_device_monitor *sender) {
+        assert_return(m, -EINVAL);
+        assert_return(sender, -EINVAL);
+
+        m->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid;
+        return 0;
+}
+
+_public_ int sd_device_monitor_set_receive_buffer_size(sd_device_monitor *m, size_t size) {
+        int r, n = (int) size;
+
+        assert_return(m, -EINVAL);
+        assert_return((size_t) n == size, -EINVAL);
+
+        if (setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUFFORCE, n) < 0) {
+                r = setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUF, n);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int device_monitor_disconnect(sd_device_monitor *m) {
+        assert(m);
+
+        m->sock = safe_close(m->sock);
+        return 0;
+}
+
+int device_monitor_get_fd(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        return m->sock;
+}
+
+int device_monitor_new_full(sd_device_monitor **ret, MonitorNetlinkGroup group, int fd) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *m = NULL;
+        _cleanup_close_ int sock = -1;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(group >= 0 && group < _MONITOR_NETLINK_GROUP_MAX, -EINVAL);
+
+        if (group == MONITOR_GROUP_UDEV &&
+            access("/run/udev/control", F_OK) < 0 &&
+            dev_is_devtmpfs() <= 0) {
+
+                /*
+                 * 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.
+                 */
+
+                log_debug("sd-device-monitor: The udev service seems not to be active, disabling the monitor");
+                group = MONITOR_GROUP_NONE;
+        }
+
+        if (fd < 0) {
+                sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
+                if (sock < 0)
+                        return log_debug_errno(errno, "sd-device-monitor: Failed to create socket: %m");
+        }
+
+        m = new(sd_device_monitor, 1);
+        if (!m)
+                return -ENOMEM;
+
+        *m = (sd_device_monitor) {
+                .n_ref = 1,
+                .sock = fd >= 0 ? fd : TAKE_FD(sock),
+                .bound = fd >= 0,
+                .snl.nl.nl_family = AF_NETLINK,
+                .snl.nl.nl_groups = group,
+        };
+
+        if (fd >= 0) {
+                r = monitor_set_nl_address(m);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-monitor: Failed to set netlink address: %m");
+        }
+
+        *ret = TAKE_PTR(m);
+        return 0;
+}
+
+_public_ int sd_device_monitor_new(sd_device_monitor **ret) {
+        return device_monitor_new_full(ret, MONITOR_GROUP_UDEV, -1);
+}
+
+_public_ int sd_device_monitor_stop(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        m->event_source = sd_event_source_unref(m->event_source);
+        (void) device_monitor_disconnect(m);
+
+        return 0;
+}
+
+static int device_monitor_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        sd_device_monitor *m = userdata;
+
+        assert(m);
+
+        if (device_monitor_receive_device(m, &device) <= 0)
+                return 0;
+
+        if (m->callback)
+                return m->callback(m, device, m->userdata);
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_start(sd_device_monitor *m, sd_device_monitor_handler_t callback, void *userdata) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (!m->event) {
+                r = sd_device_monitor_attach_event(m, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        r = device_monitor_enable_receiving(m);
+        if (r < 0)
+                return r;
+
+        m->callback = callback;
+        m->userdata = userdata;
+
+        r = sd_event_add_io(m->event, &m->event_source, m->sock, EPOLLIN, device_monitor_event_handler, m);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_source_set_description(m->event_source, "sd-device-monitor");
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_detach_event(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        (void) sd_device_monitor_stop(m);
+        m->event = sd_event_unref(m->event);
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_attach_event(sd_device_monitor *m, sd_event *event) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->event, -EBUSY);
+
+        if (event)
+                m->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&m->event);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+_public_ sd_event *sd_device_monitor_get_event(sd_device_monitor *m) {
+        assert_return(m, NULL);
+
+        return m->event;
+}
+
+_public_ sd_event_source *sd_device_monitor_get_event_source(sd_device_monitor *m) {
+        assert_return(m, NULL);
+
+        return m->event_source;
+}
+
+int device_monitor_enable_receiving(sd_device_monitor *m) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = sd_device_monitor_filter_update(m);
+        if (r < 0)
+                return log_debug_errno(r, "sd-device-monitor: Failed to update filter: %m");
+
+        if (!m->bound) {
+                /* enable receiving of sender credentials */
+                r = setsockopt_int(m->sock, SOL_SOCKET, SO_PASSCRED, true);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-monitor: Failed to set socket option SO_PASSCRED: %m");
+
+                if (bind(m->sock, &m->snl.sa, sizeof(struct sockaddr_nl)) < 0)
+                        return log_debug_errno(errno, "sd-device-monitor: Failed to bind monitoring socket: %m");
+
+                m->bound = true;
+
+                r = monitor_set_nl_address(m);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-monitor: Failed to set address: %m");
+        }
+
+        return 0;
+}
+
+static sd_device_monitor *device_monitor_free(sd_device_monitor *m) {
+        assert(m);
+
+        (void) sd_device_monitor_detach_event(m);
+
+        hashmap_free_free_free(m->subsystem_filter);
+        set_free_free(m->tag_filter);
+
+        return mfree(m);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_monitor, sd_device_monitor, device_monitor_free);
+
+static int passes_filter(sd_device_monitor *m, sd_device *device) {
+        const char *tag, *subsystem, *devtype, *s, *d = NULL;
+        Iterator i;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        if (hashmap_isempty(m->subsystem_filter))
+                goto tag;
+
+        r = sd_device_get_subsystem(device, &s);
+        if (r < 0)
+                return r;
+
+        r = sd_device_get_devtype(device, &d);
+        if (r < 0 && r != -ENOENT)
+                return r;
+
+        HASHMAP_FOREACH_KEY(devtype, subsystem, m->subsystem_filter, i) {
+                if (!streq(s, subsystem))
+                        continue;
+
+                if (!devtype)
+                        goto tag;
+
+                if (!d)
+                        continue;
+
+                if (streq(d, devtype))
+                        goto tag;
+        }
+
+        return 0;
+
+tag:
+        if (set_isempty(m->tag_filter))
+                return 1;
+
+        SET_FOREACH(tag, m->tag_filter, i)
+                if (sd_device_has_tag(device, tag) > 0)
+                        return 1;
+
+        return 0;
+}
+
+int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        union {
+                monitor_netlink_header nlh;
+                char raw[8192];
+        } buf;
+        struct iovec iov = {
+                .iov_base = &buf,
+                .iov_len = sizeof(buf)
+        };
+        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+        union sockaddr_union snl;
+        struct msghdr smsg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = cred_msg,
+                .msg_controllen = sizeof(cred_msg),
+                .msg_name = &snl,
+                .msg_namelen = sizeof(snl),
+        };
+        struct cmsghdr *cmsg;
+        struct ucred *cred;
+        ssize_t buflen, bufpos;
+        bool is_initialized = false;
+        int r;
+
+        assert(ret);
+
+        buflen = recvmsg(m->sock, &smsg, 0);
+        if (buflen < 0) {
+                if (errno != EINTR)
+                        log_debug_errno(errno, "sd-device-monitor: Failed to receive message: %m");
+                return -errno;
+        }
+
+        if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "sd-device-monitor: Invalid message length.");
+
+        if (snl.nl.nl_groups == MONITOR_GROUP_NONE) {
+                /* unicast message, check if we trust the sender */
+                if (m->snl_trusted_sender.nl.nl_pid == 0 ||
+                    snl.nl.nl_pid != m->snl_trusted_sender.nl.nl_pid)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Unicast netlink message ignored.");
+
+        } else if (snl.nl.nl_groups == MONITOR_GROUP_KERNEL) {
+                if (snl.nl.nl_pid > 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Multicast kernel netlink message from PID %"PRIu32" ignored.", snl.nl.nl_pid);
+        }
+
+        cmsg = CMSG_FIRSTHDR(&smsg);
+        if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS)
+                return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                       "sd-device-monitor: No sender credentials received, message ignored.");
+
+        cred = (struct ucred*) CMSG_DATA(cmsg);
+        if (cred->uid != 0)
+                return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                       "sd-device-monitor: Sender uid="UID_FMT", message ignored.", cred->uid);
+
+        if (streq(buf.raw, "libudev")) {
+                /* udev message needs proper version magic */
+                if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message signature (%x != %x)",
+                                               buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC));
+
+                if (buf.nlh.properties_off+32 > (size_t) buflen)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message length (%u > %zd)",
+                                               buf.nlh.properties_off+32, buflen);
+
+                bufpos = buf.nlh.properties_off;
+
+                /* devices received from udev are always initialized */
+                is_initialized = true;
+
+        } else {
+                /* kernel message with header */
+                bufpos = strlen(buf.raw) + 1;
+                if ((size_t) bufpos < sizeof("a@/d") || bufpos >= buflen)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message length");
+
+                /* check message header */
+                if (!strstr(buf.raw, "@/"))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message header");
+        }
+
+        r = device_new_from_nulstr(&device, (uint8_t*) &buf.raw[bufpos], buflen - bufpos);
+        if (r < 0)
+                return log_debug_errno(r, "sd-device-monitor: Failed to create device from received message: %m");
+
+        if (is_initialized)
+                device_set_is_initialized(device);
+
+        /* Skip device, if it does not pass the current filter */
+        r = passes_filter(m, device);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to check received device passing filter: %m");
+        if (r == 0)
+                log_device_debug(device, "sd-device-monitor: Received device does not pass filter, ignoring");
+        else
+                *ret = TAKE_PTR(device);
+
+        return r;
+}
+
+static uint32_t string_hash32(const char *str) {
+        return MurmurHash2(str, strlen(str), 0);
+}
+
+/* Get a bunch of bit numbers out of the hash, and set the bits in our bit field */
+static uint64_t string_bloom64(const char *str) {
+        uint64_t bits = 0;
+        uint32_t hash = string_hash32(str);
+
+        bits |= 1LLU << (hash & 63);
+        bits |= 1LLU << ((hash >> 6) & 63);
+        bits |= 1LLU << ((hash >> 12) & 63);
+        bits |= 1LLU << ((hash >> 18) & 63);
+        return bits;
+}
+
+int device_monitor_send_device(
+                sd_device_monitor *m,
+                sd_device_monitor *destination,
+                sd_device *device) {
+
+        monitor_netlink_header nlh = {
+                .prefix = "libudev",
+                .magic = htobe32(UDEV_MONITOR_MAGIC),
+                .header_size = sizeof nlh,
+        };
+        struct iovec iov[2] = {
+                { .iov_base = &nlh, .iov_len = sizeof nlh },
+        };
+        struct msghdr smsg = {
+                .msg_iov = iov,
+                .msg_iovlen = 2,
+        };
+        /* default destination for sending */
+        union sockaddr_union default_destination = {
+                .nl.nl_family = AF_NETLINK,
+                .nl.nl_groups = MONITOR_GROUP_UDEV,
+        };
+        uint64_t tag_bloom_bits;
+        const char *buf, *val;
+        ssize_t count;
+        size_t blen;
+        int r;
+
+        assert(m);
+        assert(device);
+
+        r = device_get_properties_nulstr(device, (const uint8_t **) &buf, &blen);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device properties: %m");
+        if (blen < 32) {
+                log_device_debug(device, "sd-device-monitor: Length of device property nulstr is too small to contain valid device information");
+                return -EINVAL;
+        }
+
+        /* fill in versioned header */
+        r = sd_device_get_subsystem(device, &val);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device subsystem: %m");
+        nlh.filter_subsystem_hash = htobe32(string_hash32(val));
+
+        if (sd_device_get_devtype(device, &val) >= 0)
+                nlh.filter_devtype_hash = htobe32(string_hash32(val));
+
+        /* add tag bloom filter */
+        tag_bloom_bits = 0;
+        FOREACH_DEVICE_TAG(device, val)
+                tag_bloom_bits |= string_bloom64(val);
+
+        if (tag_bloom_bits > 0) {
+                nlh.filter_tag_bloom_hi = htobe32(tag_bloom_bits >> 32);
+                nlh.filter_tag_bloom_lo = htobe32(tag_bloom_bits & 0xffffffff);
+        }
+
+        /* add properties list */
+        nlh.properties_off = iov[0].iov_len;
+        nlh.properties_len = blen;
+        iov[1] = IOVEC_MAKE((char*) buf, blen);
+
+        /*
+         * Use custom address for target, or the default one.
+         *
+         * If we send to a multicast group, we will get
+         * ECONNREFUSED, which is expected.
+         */
+        smsg.msg_name = destination ? &destination->snl : &default_destination;
+        smsg.msg_namelen = sizeof(struct sockaddr_nl);
+        count = sendmsg(m->sock, &smsg, 0);
+        if (count < 0) {
+                if (!destination && errno == ECONNREFUSED) {
+                        log_device_debug(device, "sd-device-monitor: Passed to netlink monitor");
+                        return 0;
+                } else
+                        return log_device_debug_errno(device, errno, "sd-device-monitor: Failed to send device to netlink monitor: %m");
+        }
+
+        log_device_debug(device, "sd-device-monitor: Passed %zi byte to netlink monitor", count);
+        return count;
+}
+
+static void bpf_stmt(struct sock_filter *ins, unsigned *i,
+                     unsigned short code, unsigned data) {
+        ins[(*i)++] = (struct sock_filter) {
+                .code = code,
+                .k = data,
+        };
+}
+
+static void bpf_jmp(struct sock_filter *ins, unsigned *i,
+                    unsigned short code, unsigned data,
+                    unsigned short jt, unsigned short jf) {
+        ins[(*i)++] = (struct sock_filter) {
+                .code = code,
+                .jt = jt,
+                .jf = jf,
+                .k = data,
+        };
+}
+
+_public_ int sd_device_monitor_filter_update(sd_device_monitor *m) {
+        struct sock_filter ins[512] = {};
+        struct sock_fprog filter;
+        const char *subsystem, *devtype, *tag;
+        unsigned i = 0;
+        Iterator it;
+
+        assert_return(m, -EINVAL);
+
+        if (m->filter_uptodate)
+                return 0;
+
+        if (hashmap_isempty(m->subsystem_filter) &&
+            set_isempty(m->tag_filter)) {
+                m->filter_uptodate = true;
+                return 0;
+        }
+
+        /* load magic in A */
+        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, magic));
+        /* jump if magic matches */
+        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0);
+        /* wrong magic, pass packet */
+        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+        if (!set_isempty(m->tag_filter)) {
+                int tag_matches = set_size(m->tag_filter);
+
+                /* add all tags matches */
+                SET_FOREACH(tag, m->tag_filter, it) {
+                        uint64_t tag_bloom_bits = string_bloom64(tag);
+                        uint32_t tag_bloom_hi = tag_bloom_bits >> 32;
+                        uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff;
+
+                        /* load device bloom bits in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_hi));
+                        /* clear bits (tag bits & bloom bits) */
+                        bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi);
+                        /* jump to next tag if it does not match */
+                        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3);
+
+                        /* load device bloom bits in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_lo));
+                        /* clear bits (tag bits & bloom bits) */
+                        bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo);
+                        /* jump behind end of tag match block if tag matches */
+                        tag_matches--;
+                        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0);
+                }
+
+                /* nothing matched, drop packet */
+                bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+        }
+
+        /* add all subsystem matches */
+        if (!hashmap_isempty(m->subsystem_filter)) {
+                HASHMAP_FOREACH_KEY(devtype, subsystem, m->subsystem_filter, it) {
+                        uint32_t hash = string_hash32(subsystem);
+
+                        /* load device subsystem value in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_subsystem_hash));
+                        if (!devtype) {
+                                /* jump if subsystem does not match */
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
+                        } else {
+                                /* jump if subsystem does not match */
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3);
+                                /* load device devtype value in A */
+                                bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_devtype_hash));
+                                /* jump if value does not match */
+                                hash = string_hash32(devtype);
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
+                        }
+
+                        /* matched, pass packet */
+                        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+                        if (i+1 >= ELEMENTSOF(ins))
+                                return -E2BIG;
+                }
+
+                /* nothing matched, drop packet */
+                bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+        }
+
+        /* matched, pass packet */
+        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+        /* install filter */
+        filter = (struct sock_fprog) {
+                .len = i,
+                .filter = ins,
+        };
+        if (setsockopt(m->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0)
+                return -errno;
+
+        m->filter_uptodate = true;
+        return 0;
+}
+
+_public_ int sd_device_monitor_filter_add_match_subsystem_devtype(sd_device_monitor *m, const char *subsystem, const char *devtype) {
+        _cleanup_free_ char *s = NULL, *d = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        s = strdup(subsystem);
+        if (!s)
+                return -ENOMEM;
+
+        if (devtype) {
+                d = strdup(devtype);
+                if (!d)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_ensure_allocated(&m->subsystem_filter, NULL);
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(m->subsystem_filter, s, d);
+        if (r < 0)
+                return r;
+
+        s = d = NULL;
+        m->filter_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_filter_add_match_tag(sd_device_monitor *m, const char *tag) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        t = strdup(tag);
+        if (!t)
+                return -ENOMEM;
+
+        r = set_ensure_allocated(&m->tag_filter, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = set_put(m->tag_filter, t);
+        if (r == -EEXIST)
+                return 0;
+        if (r < 0)
+                return r;
+
+        TAKE_PTR(t);
+        m->filter_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_filter_remove(sd_device_monitor *m) {
+        static const struct sock_fprog filter = { 0, NULL };
+
+        assert_return(m, -EINVAL);
+
+        m->subsystem_filter = hashmap_free_free_free(m->subsystem_filter);
+        m->tag_filter = set_free_free(m->tag_filter);
+
+        if (setsockopt(m->sock, SOL_SOCKET, SO_DETACH_FILTER, &filter, sizeof(filter)) < 0)
+                return -errno;
+
+        m->filter_uptodate = true;
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/device-private.c b/src/libsystemd/sd-device/device-private.c
new file mode 100644
index 0000000..76267a1
--- /dev/null
+++ b/src/libsystemd/sd-device/device-private.c
@@ -0,0 +1,956 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <ctype.h>
+#include <net/if.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-internal.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "refcnt.h"
+#include "set.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "strxcpyx.h"
+#include "tmpfile-util.h"
+#include "user-util.h"
+#include "util.h"
+
+int device_add_property(sd_device *device, const char *key, const char *value) {
+        int r;
+
+        assert(device);
+        assert(key);
+
+        r = device_add_property_aux(device, key, value, false);
+        if (r < 0)
+                return r;
+
+        if (key[0] != '.') {
+                r = device_add_property_aux(device, key, value, true);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+void device_set_devlink_priority(sd_device *device, int priority) {
+        assert(device);
+
+        device->devlink_priority = priority;
+}
+
+void device_set_is_initialized(sd_device *device) {
+        assert(device);
+
+        device->is_initialized = true;
+}
+
+int device_ensure_usec_initialized(sd_device *device, sd_device *device_old) {
+        usec_t when;
+
+        assert(device);
+
+        if (device_old && device_old->usec_initialized > 0)
+                when = device_old->usec_initialized;
+        else
+                when = now(CLOCK_MONOTONIC);
+
+        return device_set_usec_initialized(device, when);
+}
+
+uint64_t device_get_properties_generation(sd_device *device) {
+        assert(device);
+
+        return device->properties_generation;
+}
+
+uint64_t device_get_tags_generation(sd_device *device) {
+        assert(device);
+
+        return device->tags_generation;
+}
+
+uint64_t device_get_devlinks_generation(sd_device *device) {
+        assert(device);
+
+        return device->devlinks_generation;
+}
+
+int device_get_devnode_mode(sd_device *device, mode_t *mode) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devmode == (mode_t) -1)
+                return -ENOENT;
+
+        if (mode)
+                *mode = device->devmode;
+
+        return 0;
+}
+
+int device_get_devnode_uid(sd_device *device, uid_t *uid) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devuid == (uid_t) -1)
+                return -ENOENT;
+
+        if (uid)
+                *uid = device->devuid;
+
+        return 0;
+}
+
+static int device_set_devuid(sd_device *device, const char *uid) {
+        unsigned u;
+        int r;
+
+        assert(device);
+        assert(uid);
+
+        r = safe_atou(uid, &u);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(device, "DEVUID", uid);
+        if (r < 0)
+                return r;
+
+        device->devuid = u;
+
+        return 0;
+}
+
+int device_get_devnode_gid(sd_device *device, gid_t *gid) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devgid == (gid_t) -1)
+                return -ENOENT;
+
+        if (gid)
+                *gid = device->devgid;
+
+        return 0;
+}
+
+static int device_set_devgid(sd_device *device, const char *gid) {
+        unsigned g;
+        int r;
+
+        assert(device);
+        assert(gid);
+
+        r = safe_atou(gid, &g);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(device, "DEVGID", gid);
+        if (r < 0)
+                return r;
+
+        device->devgid = g;
+
+        return 0;
+}
+
+static int device_amend(sd_device *device, const char *key, const char *value) {
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(value);
+
+        if (streq(key, "DEVPATH")) {
+                char *path;
+
+                path = strjoina("/sys", value);
+
+                /* the caller must verify or trust this data (e.g., if it comes from the kernel) */
+                r = device_set_syspath(device, path, false);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set syspath to '%s': %m", path);
+        } else if (streq(key, "SUBSYSTEM")) {
+                r = device_set_subsystem(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem to '%s': %m", value);
+        } else if (streq(key, "DEVTYPE")) {
+                r = device_set_devtype(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devtype to '%s': %m", value);
+        } else if (streq(key, "DEVNAME")) {
+                r = device_set_devname(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devname to '%s': %m", value);
+        } else if (streq(key, "USEC_INITIALIZED")) {
+                usec_t t;
+
+                r = safe_atou64(value, &t);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to parse timestamp '%s': %m", value);
+
+                r = device_set_usec_initialized(device, t);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set usec-initialized to '%s': %m", value);
+        } else if (streq(key, "DRIVER")) {
+                r = device_set_driver(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set driver to '%s': %m", value);
+        } else if (streq(key, "IFINDEX")) {
+                r = device_set_ifindex(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set ifindex to '%s': %m", value);
+        } else if (streq(key, "DEVMODE")) {
+                r = device_set_devmode(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devmode to '%s': %m", value);
+        } else if (streq(key, "DEVUID")) {
+                r = device_set_devuid(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devuid to '%s': %m", value);
+        } else if (streq(key, "DEVGID")) {
+                r = device_set_devgid(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devgid to '%s': %m", value);
+        } else if (streq(key, "DEVLINKS")) {
+                const char *word, *state;
+                size_t l;
+
+                FOREACH_WORD(word, l, value, state) {
+                        char devlink[l + 1];
+
+                        strncpy(devlink, word, l);
+                        devlink[l] = '\0';
+
+                        r = device_add_devlink(device, devlink);
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to add devlink '%s': %m", devlink);
+                }
+        } else if (streq(key, "TAGS")) {
+                const char *word, *state;
+                size_t l;
+
+                FOREACH_WORD_SEPARATOR(word, l, value, ":", state) {
+                        char tag[l + 1];
+
+                        (void) strncpy(tag, word, l);
+                        tag[l] = '\0';
+
+                        r = device_add_tag(device, tag);
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to add tag '%s': %m", tag);
+                }
+        } else {
+                r = device_add_property_internal(device, key, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to add property '%s=%s': %m", key, value);
+        }
+
+        return 0;
+}
+
+static const char* const device_action_table[_DEVICE_ACTION_MAX] = {
+        [DEVICE_ACTION_ADD] = "add",
+        [DEVICE_ACTION_REMOVE] = "remove",
+        [DEVICE_ACTION_CHANGE] = "change",
+        [DEVICE_ACTION_MOVE] = "move",
+        [DEVICE_ACTION_ONLINE] = "online",
+        [DEVICE_ACTION_OFFLINE] = "offline",
+        [DEVICE_ACTION_BIND] = "bind",
+        [DEVICE_ACTION_UNBIND] = "unbind",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(device_action, DeviceAction);
+
+static int device_append(sd_device *device, char *key, const char **_major, const char **_minor, uint64_t *_seqnum,
+                         DeviceAction *_action) {
+        DeviceAction action = _DEVICE_ACTION_INVALID;
+        uint64_t seqnum = 0;
+        const char *major = NULL, *minor = NULL;
+        char *value;
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(_major);
+        assert(_minor);
+        assert(_seqnum);
+        assert(_action);
+
+        value = strchr(key, '=');
+        if (!value) {
+                log_device_debug(device, "sd-device: Not a key-value pair: '%s'", key);
+                return -EINVAL;
+        }
+
+        *value = '\0';
+
+        value++;
+
+        if (streq(key, "MAJOR"))
+                major = value;
+        else if (streq(key, "MINOR"))
+                minor = value;
+        else {
+                if (streq(key, "ACTION")) {
+                        action = device_action_from_string(value);
+                        if (action == _DEVICE_ACTION_INVALID)
+                                return -EINVAL;
+                } else if (streq(key, "SEQNUM")) {
+                        r = safe_atou64(value, &seqnum);
+                        if (r < 0)
+                                return r;
+                        else if (seqnum == 0)
+                                 /* kernel only sends seqnum > 0 */
+                                return -EINVAL;
+                }
+
+                r = device_amend(device, key, value);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major != 0)
+                *_major = major;
+
+        if (minor != 0)
+                *_minor = minor;
+
+        if (action != _DEVICE_ACTION_INVALID)
+                *_action = action;
+
+        if (seqnum > 0)
+                *_seqnum = seqnum;
+
+        return 0;
+}
+
+void device_seal(sd_device *device) {
+        assert(device);
+
+        device->sealed = true;
+}
+
+static int device_verify(sd_device *device, DeviceAction action, uint64_t seqnum) {
+        assert(device);
+
+        if (!device->devpath || !device->subsystem || action == _DEVICE_ACTION_INVALID || seqnum == 0) {
+                log_device_debug(device, "sd-device: Device created from strv or nulstr lacks devpath, subsystem, action or seqnum.");
+                return -EINVAL;
+        }
+
+        device->sealed = true;
+
+        return 0;
+}
+
+int device_new_from_strv(sd_device **ret, char **strv) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        char **key;
+        const char *major = NULL, *minor = NULL;
+        DeviceAction action = _DEVICE_ACTION_INVALID;
+        uint64_t seqnum = 0;
+        int r;
+
+        assert(ret);
+        assert(strv);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(key, strv) {
+                r = device_append(device, *key, &major, &minor, &seqnum, &action);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devnum %s:%s: %m", major, minor);
+        }
+
+        r = device_verify(device, action, seqnum);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+
+        return 0;
+}
+
+int device_new_from_nulstr(sd_device **ret, uint8_t *nulstr, size_t len) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        const char *major = NULL, *minor = NULL;
+        DeviceAction action = _DEVICE_ACTION_INVALID;
+        uint64_t seqnum = 0;
+        unsigned i = 0;
+        int r;
+
+        assert(ret);
+        assert(nulstr);
+        assert(len);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        while (i < len) {
+                char *key;
+                const char *end;
+
+                key = (char*)&nulstr[i];
+                end = memchr(key, '\0', len - i);
+                if (!end) {
+                        log_device_debug(device, "sd-device: Failed to parse nulstr");
+                        return -EINVAL;
+                }
+                i += end - key + 1;
+
+                r = device_append(device, key, &major, &minor, &seqnum, &action);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devnum %s:%s: %m", major, minor);
+        }
+
+        r = device_verify(device, action, seqnum);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+
+        return 0;
+}
+
+static int device_update_properties_bufs(sd_device *device) {
+        const char *val, *prop;
+        _cleanup_free_ char **buf_strv = NULL;
+        _cleanup_free_ uint8_t *buf_nulstr = NULL;
+        size_t allocated_nulstr = 0;
+        size_t nulstr_len = 0, num = 0, i = 0;
+
+        assert(device);
+
+        if (!device->properties_buf_outdated)
+                return 0;
+
+        FOREACH_DEVICE_PROPERTY(device, prop, val) {
+                size_t len = 0;
+
+                len = strlen(prop) + 1 + strlen(val);
+
+                buf_nulstr = GREEDY_REALLOC0(buf_nulstr, allocated_nulstr, nulstr_len + len + 2);
+                if (!buf_nulstr)
+                        return -ENOMEM;
+
+                strscpyl((char *)buf_nulstr + nulstr_len, len + 1, prop, "=", val, NULL);
+                nulstr_len += len + 1;
+                ++num;
+        }
+
+        /* build buf_strv from buf_nulstr */
+        buf_strv = new0(char *, num + 1);
+        if (!buf_strv)
+                return -ENOMEM;
+
+        NULSTR_FOREACH(val, (char*) buf_nulstr) {
+                buf_strv[i] = (char *) val;
+                assert(i < num);
+                i++;
+        }
+
+        free_and_replace(device->properties_nulstr, buf_nulstr);
+        device->properties_nulstr_len = nulstr_len;
+        free_and_replace(device->properties_strv, buf_strv);
+
+        device->properties_buf_outdated = false;
+
+        return 0;
+}
+
+int device_get_properties_nulstr(sd_device *device, const uint8_t **nulstr, size_t *len) {
+        int r;
+
+        assert(device);
+        assert(nulstr);
+        assert(len);
+
+        r = device_update_properties_bufs(device);
+        if (r < 0)
+                return r;
+
+        *nulstr = device->properties_nulstr;
+        *len = device->properties_nulstr_len;
+
+        return 0;
+}
+
+int device_get_properties_strv(sd_device *device, char ***strv) {
+        int r;
+
+        assert(device);
+        assert(strv);
+
+        r = device_update_properties_bufs(device);
+        if (r < 0)
+                return r;
+
+        *strv = device->properties_strv;
+
+        return 0;
+}
+
+int device_get_devlink_priority(sd_device *device, int *priority) {
+        int r;
+
+        assert(device);
+        assert(priority);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        *priority = device->devlink_priority;
+
+        return 0;
+}
+
+int device_get_watch_handle(sd_device *device, int *handle) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->watch_handle < 0)
+                return -ENOENT;
+
+        if (handle)
+                *handle = device->watch_handle;
+
+        return 0;
+}
+
+void device_set_watch_handle(sd_device *device, int handle) {
+        assert(device);
+
+        device->watch_handle = handle;
+}
+
+int device_rename(sd_device *device, const char *name) {
+        _cleanup_free_ char *dirname = NULL;
+        char *new_syspath;
+        const char *interface;
+        int r;
+
+        assert(device);
+        assert(name);
+
+        dirname = dirname_malloc(device->syspath);
+        if (!dirname)
+                return -ENOMEM;
+
+        new_syspath = strjoina(dirname, "/", name);
+
+        /* the user must trust that the new name is correct */
+        r = device_set_syspath(device, new_syspath, false);
+        if (r < 0)
+                return r;
+
+        r = sd_device_get_property_value(device, "INTERFACE", &interface);
+        if (r >= 0) {
+                /* like DEVPATH_OLD, INTERFACE_OLD is not saved to the db, but only stays around for the current event */
+                r = device_add_property_internal(device, "INTERFACE_OLD", interface);
+                if (r < 0)
+                        return r;
+
+                r = device_add_property_internal(device, "INTERFACE", name);
+                if (r < 0)
+                        return r;
+        } else if (r != -ENOENT)
+                return r;
+
+        return 0;
+}
+
+int device_shallow_clone(sd_device *old_device, sd_device **new_device) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(old_device);
+        assert(new_device);
+
+        r = device_new_aux(&ret);
+        if (r < 0)
+                return r;
+
+        r = device_set_syspath(ret, old_device->syspath, false);
+        if (r < 0)
+                return r;
+
+        r = device_set_subsystem(ret, old_device->subsystem);
+        if (r < 0)
+                return r;
+
+        ret->devnum = old_device->devnum;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_clone_with_db(sd_device *old_device, sd_device **new_device) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(old_device);
+        assert(new_device);
+
+        r = device_shallow_clone(old_device, &ret);
+        if (r < 0)
+                return r;
+
+        r = device_read_db(ret);
+        if (r < 0)
+                return r;
+
+        ret->sealed = true;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_new_from_synthetic_event(sd_device **new_device, const char *syspath, const char *action) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(new_device);
+        assert(syspath);
+        assert(action);
+
+        r = sd_device_new_from_syspath(&ret, syspath);
+        if (r < 0)
+                return r;
+
+        r = device_read_uevent_file(ret);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(ret, "ACTION", action);
+        if (r < 0)
+                return r;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_new_from_stat_rdev(sd_device **ret, const struct stat *st) {
+        char type;
+
+        assert(ret);
+        assert(st);
+
+        if (S_ISBLK(st->st_mode))
+                type = 'b';
+        else if (S_ISCHR(st->st_mode))
+                type = 'c';
+        else
+                return -ENOTTY;
+
+        return sd_device_new_from_devnum(ret, type, st->st_rdev);
+}
+
+int device_copy_properties(sd_device *device_dst, sd_device *device_src) {
+        const char *property, *value;
+        Iterator i;
+        int r;
+
+        assert(device_dst);
+        assert(device_src);
+
+        r = device_properties_prepare(device_src);
+        if (r < 0)
+                return r;
+
+        ORDERED_HASHMAP_FOREACH_KEY(value, property, device_src->properties_db, i) {
+                r = device_add_property_aux(device_dst, property, value, true);
+                if (r < 0)
+                        return r;
+        }
+
+        ORDERED_HASHMAP_FOREACH_KEY(value, property, device_src->properties, i) {
+                r = device_add_property_aux(device_dst, property, value, false);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+void device_cleanup_tags(sd_device *device) {
+        assert(device);
+
+        set_free_free(device->tags);
+        device->tags = NULL;
+        device->property_tags_outdated = true;
+        device->tags_generation++;
+}
+
+void device_cleanup_devlinks(sd_device *device) {
+        assert(device);
+
+        set_free_free(device->devlinks);
+        device->devlinks = NULL;
+        device->property_devlinks_outdated = true;
+        device->devlinks_generation++;
+}
+
+void device_remove_tag(sd_device *device, const char *tag) {
+        assert(device);
+        assert(tag);
+
+        free(set_remove(device->tags, tag));
+        device->property_tags_outdated = true;
+        device->tags_generation++;
+}
+
+static int device_tag(sd_device *device, const char *tag, bool add) {
+        const char *id;
+        char *path;
+        int r;
+
+        assert(device);
+        assert(tag);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/tags/", tag, "/", id);
+
+        if (add) {
+                r = touch_file(path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, 0444);
+                if (r < 0)
+                        return r;
+        } else {
+                r = unlink(path);
+                if (r < 0 && errno != ENOENT)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+int device_tag_index(sd_device *device, sd_device *device_old, bool add) {
+        const char *tag;
+        int r = 0, k;
+
+        if (add && device_old) {
+                /* delete possible left-over tags */
+                FOREACH_DEVICE_TAG(device_old, tag) {
+                        if (!sd_device_has_tag(device, tag)) {
+                                k = device_tag(device_old, tag, false);
+                                if (r >= 0 && k < 0)
+                                        r = k;
+                        }
+                }
+        }
+
+        FOREACH_DEVICE_TAG(device, tag) {
+                k = device_tag(device, tag, add);
+                if (r >= 0 && k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static bool device_has_info(sd_device *device) {
+        assert(device);
+
+        if (!set_isempty(device->devlinks))
+                return true;
+
+        if (device->devlink_priority != 0)
+                return true;
+
+        if (!ordered_hashmap_isempty(device->properties_db))
+                return true;
+
+        if (!set_isempty(device->tags))
+                return true;
+
+        if (device->watch_handle >= 0)
+                return true;
+
+        return false;
+}
+
+void device_set_db_persist(sd_device *device) {
+        assert(device);
+
+        device->db_persist = true;
+}
+
+int device_update_db(sd_device *device) {
+        const char *id;
+        char *path;
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *path_tmp = NULL;
+        bool has_info;
+        int r;
+
+        assert(device);
+
+        has_info = device_has_info(device);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        /* do not store anything for otherwise empty devices */
+        if (!has_info && major(device->devnum) == 0 && device->ifindex == 0) {
+                r = unlink(path);
+                if (r < 0 && errno != ENOENT)
+                        return -errno;
+
+                return 0;
+        }
+
+        /* write a database file */
+        r = mkdir_parents(path, 0755);
+        if (r < 0)
+                return r;
+
+        r = fopen_temporary(path, &f, &path_tmp);
+        if (r < 0)
+                return r;
+
+        /*
+         * set 'sticky' bit to indicate that we should not clean the
+         * database when we transition from initramfs to the real root
+         */
+        if (device->db_persist) {
+                r = fchmod(fileno(f), 01644);
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+        } else {
+                r = fchmod(fileno(f), 0644);
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+        }
+
+        if (has_info) {
+                const char *property, *value, *tag;
+                Iterator i;
+
+                if (major(device->devnum) > 0) {
+                        const char *devlink;
+
+                        FOREACH_DEVICE_DEVLINK(device, devlink)
+                                fprintf(f, "S:%s\n", devlink + STRLEN("/dev/"));
+
+                        if (device->devlink_priority != 0)
+                                fprintf(f, "L:%i\n", device->devlink_priority);
+
+                        if (device->watch_handle >= 0)
+                                fprintf(f, "W:%i\n", device->watch_handle);
+                }
+
+                if (device->usec_initialized > 0)
+                        fprintf(f, "I:"USEC_FMT"\n", device->usec_initialized);
+
+                ORDERED_HASHMAP_FOREACH_KEY(value, property, device->properties_db, i)
+                        fprintf(f, "E:%s=%s\n", property, value);
+
+                FOREACH_DEVICE_TAG(device, tag)
+                        fprintf(f, "G:%s\n", tag);
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                goto fail;
+
+        r = rename(path_tmp, path);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        log_device_debug(device, "sd-device: Created %s file '%s' for '%s'", has_info ? "db" : "empty",
+                         path, device->devpath);
+
+        return 0;
+
+fail:
+        (void) unlink(path);
+        (void) unlink(path_tmp);
+
+        return log_device_debug_errno(device, r, "sd-device: Failed to create %s file '%s' for '%s'", has_info ? "db" : "empty", path, device->devpath);
+}
+
+int device_delete_db(sd_device *device) {
+        const char *id;
+        char *path;
+        int r;
+
+        assert(device);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        r = unlink(path);
+        if (r < 0 && errno != ENOENT)
+                return -errno;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/device-private.h b/src/libsystemd/sd-device/device-private.h
new file mode 100644
index 0000000..062bfd6
--- /dev/null
+++ b/src/libsystemd/sd-device/device-private.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+int device_new_from_nulstr(sd_device **ret, uint8_t *nulstr, size_t len);
+int device_new_from_strv(sd_device **ret, char **strv);
+int device_new_from_stat_rdev(sd_device **ret, const struct stat *st);
+
+int device_get_id_filename(sd_device *device, const char **ret);
+
+int device_get_devlink_priority(sd_device *device, int *priority);
+int device_get_watch_handle(sd_device *device, int *handle);
+int device_get_devnode_mode(sd_device *device, mode_t *mode);
+int device_get_devnode_uid(sd_device *device, uid_t *uid);
+int device_get_devnode_gid(sd_device *device, gid_t *gid);
+
+void device_seal(sd_device *device);
+void device_set_is_initialized(sd_device *device);
+void device_set_watch_handle(sd_device *device, int fd);
+void device_set_db_persist(sd_device *device);
+void device_set_devlink_priority(sd_device *device, int priority);
+int device_ensure_usec_initialized(sd_device *device, sd_device *device_old);
+int device_add_devlink(sd_device *device, const char *devlink);
+int device_add_property(sd_device *device, const char *property, const char *value);
+int device_add_tag(sd_device *device, const char *tag);
+void device_remove_tag(sd_device *device, const char *tag);
+void device_cleanup_tags(sd_device *device);
+void device_cleanup_devlinks(sd_device *device);
+
+uint64_t device_get_properties_generation(sd_device *device);
+uint64_t device_get_tags_generation(sd_device *device);
+uint64_t device_get_devlinks_generation(sd_device *device);
+
+int device_properties_prepare(sd_device *device);
+int device_get_properties_nulstr(sd_device *device, const uint8_t **nulstr, size_t *len);
+int device_get_properties_strv(sd_device *device, char ***strv);
+
+int device_rename(sd_device *device, const char *name);
+int device_shallow_clone(sd_device *old_device, sd_device **new_device);
+int device_clone_with_db(sd_device *old_device, sd_device **new_device);
+int device_copy_properties(sd_device *device_dst, sd_device *device_src);
+int device_new_from_synthetic_event(sd_device **new_device, const char *syspath, const char *action);
+
+int device_tag_index(sd_device *dev, sd_device *dev_old, bool add);
+int device_update_db(sd_device *device);
+int device_delete_db(sd_device *device);
+int device_read_db_internal(sd_device *device, bool force);
+static inline int device_read_db(sd_device *device) {
+        return device_read_db_internal(device, false);
+}
diff --git a/src/libsystemd/sd-device/device-util.h b/src/libsystemd/sd-device/device-util.h
new file mode 100644
index 0000000..94f6174
--- /dev/null
+++ b/src/libsystemd/sd-device/device-util.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#define FOREACH_DEVICE_PROPERTY(device, key, value)                \
+        for (key = sd_device_get_property_first(device, &(value)); \
+             key;                                                  \
+             key = sd_device_get_property_next(device, &(value)))
+
+#define FOREACH_DEVICE_TAG(device, tag)             \
+        for (tag = sd_device_get_tag_first(device); \
+             tag;                                   \
+             tag = sd_device_get_tag_next(device))
+
+#define FOREACH_DEVICE_SYSATTR(device, attr)             \
+        for (attr = sd_device_get_sysattr_first(device); \
+             attr;                                       \
+             attr = sd_device_get_sysattr_next(device))
+
+#define FOREACH_DEVICE_DEVLINK(device, devlink)             \
+        for (devlink = sd_device_get_devlink_first(device); \
+             devlink;                                   \
+             devlink = sd_device_get_devlink_next(device))
+
+#define FOREACH_DEVICE(enumerator, device)                               \
+        for (device = sd_device_enumerator_get_device_first(enumerator); \
+             device;                                                     \
+             device = sd_device_enumerator_get_device_next(enumerator))
+
+#define FOREACH_SUBSYSTEM(enumerator, device)                               \
+        for (device = sd_device_enumerator_get_subsystem_first(enumerator); \
+             device;                                                        \
+             device = sd_device_enumerator_get_subsystem_next(enumerator))
+
+#define log_device_full(device, level, error, ...)                      \
+        ({                                                              \
+                const char *_sysname = NULL;                            \
+                sd_device *_d = (device);                               \
+                int _level = (level), _error = (error);                 \
+                                                                        \
+                if (_d && _unlikely_(log_get_max_level() >= _level))    \
+                        (void) sd_device_get_sysname(_d, &_sysname);    \
+                log_object_internal(_level, _error, __FILE__, __LINE__, __func__, \
+                                    _sysname ? "DEVICE=" : NULL, _sysname, \
+                                    NULL, NULL, ##__VA_ARGS__);         \
+        })
+
+#define log_device_debug(device, ...)   log_device_full(device, LOG_DEBUG, 0, ##__VA_ARGS__)
+#define log_device_info(device, ...)    log_device_full(device, LOG_INFO, 0, ##__VA_ARGS__)
+#define log_device_notice(device, ...)  log_device_full(device, LOG_NOTICE, 0, ##__VA_ARGS__)
+#define log_device_warning(device, ...) log_device_full(device, LOG_WARNING, 0, ##__VA_ARGS__)
+#define log_device_error(device, ...)   log_device_full(device, LOG_ERR, 0, ##__VA_ARGS__)
+
+#define log_device_debug_errno(device, error, ...)   log_device_full(device, LOG_DEBUG, error, ##__VA_ARGS__)
+#define log_device_info_errno(device, error, ...)    log_device_full(device, LOG_INFO, error, ##__VA_ARGS__)
+#define log_device_notice_errno(device, error, ...)  log_device_full(device, LOG_NOTICE, error, ##__VA_ARGS__)
+#define log_device_warning_errno(device, error, ...) log_device_full(device, LOG_WARNING, error, ##__VA_ARGS__)
+#define log_device_error_errno(device, error, ...)   log_device_full(device, LOG_ERR, error, ##__VA_ARGS__)
diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c
new file mode 100644
index 0000000..2a69f2e
--- /dev/null
+++ b/src/libsystemd/sd-device/sd-device.c
@@ -0,0 +1,1864 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <ctype.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-internal.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "set.h"
+#include "socket-util.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "strxcpyx.h"
+#include "util.h"
+
+int device_new_aux(sd_device **ret) {
+        sd_device *device;
+
+        assert(ret);
+
+        device = new(sd_device, 1);
+        if (!device)
+                return -ENOMEM;
+
+        *device = (sd_device) {
+                .n_ref = 1,
+                .watch_handle = -1,
+                .devmode = (mode_t) -1,
+                .devuid = (uid_t) -1,
+                .devgid = (gid_t) -1,
+        };
+
+        *ret = device;
+        return 0;
+}
+
+static sd_device *device_free(sd_device *device) {
+        assert(device);
+
+        sd_device_unref(device->parent);
+        free(device->syspath);
+        free(device->sysname);
+        free(device->devtype);
+        free(device->devname);
+        free(device->subsystem);
+        free(device->driver_subsystem);
+        free(device->driver);
+        free(device->id_filename);
+        free(device->properties_strv);
+        free(device->properties_nulstr);
+
+        ordered_hashmap_free_free_free(device->properties);
+        ordered_hashmap_free_free_free(device->properties_db);
+        hashmap_free_free_free(device->sysattr_values);
+        set_free_free(device->sysattrs);
+        set_free_free(device->tags);
+        set_free_free(device->devlinks);
+
+        return mfree(device);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device, sd_device, device_free);
+
+int device_add_property_aux(sd_device *device, const char *_key, const char *_value, bool db) {
+        OrderedHashmap **properties;
+
+        assert(device);
+        assert(_key);
+
+        if (db)
+                properties = &device->properties_db;
+        else
+                properties = &device->properties;
+
+        if (_value) {
+                _cleanup_free_ char *key = NULL, *value = NULL, *old_key = NULL, *old_value = NULL;
+                int r;
+
+                r = ordered_hashmap_ensure_allocated(properties, &string_hash_ops);
+                if (r < 0)
+                        return r;
+
+                key = strdup(_key);
+                if (!key)
+                        return -ENOMEM;
+
+                value = strdup(_value);
+                if (!value)
+                        return -ENOMEM;
+
+                old_value = ordered_hashmap_get2(*properties, key, (void**) &old_key);
+
+                r = ordered_hashmap_replace(*properties, key, value);
+                if (r < 0)
+                        return r;
+
+                key = NULL;
+                value = NULL;
+        } else {
+                _cleanup_free_ char *key = NULL;
+                _cleanup_free_ char *value = NULL;
+
+                value = ordered_hashmap_remove2(*properties, _key, (void**) &key);
+        }
+
+        if (!db) {
+                device->properties_generation++;
+                device->properties_buf_outdated = true;
+        }
+
+        return 0;
+}
+
+int device_add_property_internal(sd_device *device, const char *key, const char *value) {
+        return device_add_property_aux(device, key, value, false);
+}
+
+int device_set_syspath(sd_device *device, const char *_syspath, bool verify) {
+        _cleanup_free_ char *syspath = NULL;
+        const char *devpath;
+        int r;
+
+        assert(device);
+        assert(_syspath);
+
+        /* must be a subdirectory of /sys */
+        if (!path_startswith(_syspath, "/sys/"))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "sd-device: Syspath '%s' is not a subdirectory of /sys",
+                                       _syspath);
+
+        if (verify) {
+                r = chase_symlinks(_syspath, NULL, 0, &syspath);
+                if (r == -ENOENT)
+                        return -ENODEV; /* the device does not exist (any more?) */
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device: Failed to get target of '%s': %m", _syspath);
+
+                if (!path_startswith(syspath, "/sys")) {
+                        _cleanup_free_ char *real_sys = NULL, *new_syspath = NULL;
+                        char *p;
+
+                        /* /sys is a symlink to somewhere sysfs is mounted on? In that case, we convert the path to real sysfs to "/sys". */
+                        r = chase_symlinks("/sys", NULL, 0, &real_sys);
+                        if (r < 0)
+                                return log_debug_errno(r, "sd-device: Failed to chase symlink /sys: %m");
+
+                        p = path_startswith(syspath, real_sys);
+                        if (!p)
+                                return log_debug_errno(SYNTHETIC_ERRNO(ENODEV),
+                                                       "sd-device: Canonicalized path '%s' does not starts with sysfs mount point '%s'",
+                                                       syspath, real_sys);
+
+                        new_syspath = strjoin("/sys/", p);
+                        if (!new_syspath)
+                                return -ENOMEM;
+
+                        free_and_replace(syspath, new_syspath);
+                        path_simplify(syspath, false);
+                }
+
+                if (path_startswith(syspath,  "/sys/devices/")) {
+                        char *path;
+
+                        /* all 'devices' require an 'uevent' file */
+                        path = strjoina(syspath, "/uevent");
+                        r = access(path, F_OK);
+                        if (r < 0) {
+                                if (errno == ENOENT)
+                                        /* this is not a valid device */
+                                        return -ENODEV;
+
+                                return log_debug_errno(errno, "sd-device: %s does not have an uevent file: %m", syspath);
+                        }
+                } else {
+                        /* everything else just needs to be a directory */
+                        if (!is_dir(syspath, false))
+                                return -ENODEV;
+                }
+        } else {
+                syspath = strdup(_syspath);
+                if (!syspath)
+                        return -ENOMEM;
+        }
+
+        devpath = syspath + STRLEN("/sys");
+
+        r = device_add_property_internal(device, "DEVPATH", devpath);
+        if (r < 0)
+                return r;
+
+        free_and_replace(device->syspath, syspath);
+        device->devpath = devpath;
+        return 0;
+}
+
+_public_ int sd_device_new_from_syspath(sd_device **ret, const char *syspath) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(syspath, -EINVAL);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        r = device_set_syspath(device, syspath, true);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+        return 0;
+}
+
+_public_ int sd_device_new_from_devnum(sd_device **ret, char type, dev_t devnum) {
+        char *syspath;
+        char id[DECIMAL_STR_MAX(unsigned) * 2 + 1];
+
+        assert_return(ret, -EINVAL);
+        assert_return(IN_SET(type, 'b', 'c'), -EINVAL);
+
+        /* use /sys/dev/{block,char}/<maj>:<min> link */
+        snprintf(id, sizeof(id), "%u:%u", major(devnum), minor(devnum));
+
+        syspath = strjoina("/sys/dev/", (type == 'b' ? "block" : "char"), "/", id);
+
+        return sd_device_new_from_syspath(ret, syspath);
+}
+
+_public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *subsystem, const char *sysname) {
+        char *name, *syspath;
+        size_t len = 0;
+
+        assert_return(ret, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+        assert_return(sysname, -EINVAL);
+
+        if (streq(subsystem, "subsystem")) {
+                syspath = strjoina("/sys/subsystem/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+
+                syspath = strjoina("/sys/bus/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+
+                syspath = strjoina("/sys/class/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+        } else  if (streq(subsystem, "module")) {
+                syspath = strjoina("/sys/module/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+        } else if (streq(subsystem, "drivers")) {
+                char subsys[PATH_MAX];
+                char *driver;
+
+                strscpy(subsys, sizeof(subsys), sysname);
+                driver = strchr(subsys, ':');
+                if (driver) {
+                        driver[0] = '\0';
+                        driver++;
+
+                        syspath = strjoina("/sys/subsystem/", subsys, "/drivers/", driver);
+                        if (access(syspath, F_OK) >= 0)
+                                return sd_device_new_from_syspath(ret, syspath);
+
+                        syspath = strjoina("/sys/bus/", subsys, "/drivers/", driver);
+                        if (access(syspath, F_OK) >= 0)
+                                return sd_device_new_from_syspath(ret, syspath);
+                }
+        }
+
+        /* translate sysname back to sysfs filename */
+        name = strdupa(sysname);
+        while (name[len] != '\0') {
+                if (name[len] == '/')
+                        name[len] = '!';
+
+                len++;
+        }
+
+        syspath = strjoina("/sys/subsystem/", subsystem, "/devices/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/bus/", subsystem, "/devices/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/class/", subsystem, "/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/firmware/", subsystem, "/", sysname);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        return -ENODEV;
+}
+
+int device_set_devtype(sd_device *device, const char *_devtype) {
+        _cleanup_free_ char *devtype = NULL;
+        int r;
+
+        assert(device);
+        assert(_devtype);
+
+        devtype = strdup(_devtype);
+        if (!devtype)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "DEVTYPE", devtype);
+        if (r < 0)
+                return r;
+
+        free_and_replace(device->devtype, devtype);
+
+        return 0;
+}
+
+int device_set_ifindex(sd_device *device, const char *_ifindex) {
+        int ifindex, r;
+
+        assert(device);
+        assert(_ifindex);
+
+        r = parse_ifindex(_ifindex, &ifindex);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(device, "IFINDEX", _ifindex);
+        if (r < 0)
+                return r;
+
+        device->ifindex = ifindex;
+
+        return 0;
+}
+
+int device_set_devname(sd_device *device, const char *_devname) {
+        _cleanup_free_ char *devname = NULL;
+        int r;
+
+        assert(device);
+        assert(_devname);
+
+        if (_devname[0] != '/') {
+                r = asprintf(&devname, "/dev/%s", _devname);
+                if (r < 0)
+                        return -ENOMEM;
+        } else {
+                devname = strdup(_devname);
+                if (!devname)
+                        return -ENOMEM;
+        }
+
+        r = device_add_property_internal(device, "DEVNAME", devname);
+        if (r < 0)
+                return r;
+
+        free_and_replace(device->devname, devname);
+
+        return 0;
+}
+
+int device_set_devmode(sd_device *device, const char *_devmode) {
+        unsigned devmode;
+        int r;
+
+        assert(device);
+        assert(_devmode);
+
+        r = safe_atou(_devmode, &devmode);
+        if (r < 0)
+                return r;
+
+        if (devmode > 07777)
+                return -EINVAL;
+
+        r = device_add_property_internal(device, "DEVMODE", _devmode);
+        if (r < 0)
+                return r;
+
+        device->devmode = devmode;
+
+        return 0;
+}
+
+int device_set_devnum(sd_device *device, const char *major, const char *minor) {
+        unsigned maj = 0, min = 0;
+        int r;
+
+        assert(device);
+        assert(major);
+
+        r = safe_atou(major, &maj);
+        if (r < 0)
+                return r;
+        if (!maj)
+                return 0;
+
+        if (minor) {
+                r = safe_atou(minor, &min);
+                if (r < 0)
+                        return r;
+        }
+
+        r = device_add_property_internal(device, "MAJOR", major);
+        if (r < 0)
+                return r;
+
+        if (minor) {
+                r = device_add_property_internal(device, "MINOR", minor);
+                if (r < 0)
+                        return r;
+        }
+
+        device->devnum = makedev(maj, min);
+
+        return 0;
+}
+
+static int handle_uevent_line(sd_device *device, const char *key, const char *value, const char **major, const char **minor) {
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(value);
+        assert(major);
+        assert(minor);
+
+        if (streq(key, "DEVTYPE")) {
+                r = device_set_devtype(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "IFINDEX")) {
+                r = device_set_ifindex(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "DEVNAME")) {
+                r = device_set_devname(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "DEVMODE")) {
+                r = device_set_devmode(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "MAJOR"))
+                *major = value;
+        else if (streq(key, "MINOR"))
+                *minor = value;
+        else {
+                r = device_add_property_internal(device, key, value);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int device_read_uevent_file(sd_device *device) {
+        _cleanup_free_ char *uevent = NULL;
+        const char *syspath, *key = NULL, *value = NULL, *major = NULL, *minor = NULL;
+        char *path;
+        size_t uevent_len;
+        unsigned i;
+        int r;
+
+        enum {
+                PRE_KEY,
+                KEY,
+                PRE_VALUE,
+                VALUE,
+                INVALID_LINE,
+        } state = PRE_KEY;
+
+        assert(device);
+
+        if (device->uevent_loaded || device->sealed)
+                return 0;
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strjoina(syspath, "/uevent");
+
+        r = read_full_file(path, &uevent, &uevent_len);
+        if (r == -EACCES) {
+                /* empty uevent files may be write-only */
+                device->uevent_loaded = true;
+                return 0;
+        }
+        if (r == -ENOENT)
+                /* some devices may not have uevent files, see set_syspath() */
+                return 0;
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device: Failed to read uevent file '%s': %m", path);
+
+        device->uevent_loaded = true;
+
+        for (i = 0; i < uevent_len; i++)
+                switch (state) {
+                case PRE_KEY:
+                        if (!strchr(NEWLINE, uevent[i])) {
+                                key = &uevent[i];
+
+                                state = KEY;
+                        }
+
+                        break;
+                case KEY:
+                        if (uevent[i] == '=') {
+                                uevent[i] = '\0';
+
+                                state = PRE_VALUE;
+                        } else if (strchr(NEWLINE, uevent[i])) {
+                                uevent[i] = '\0';
+                                log_device_debug(device, "sd-device: Invalid uevent line '%s', ignoring", key);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                case PRE_VALUE:
+                        value = &uevent[i];
+                        state = VALUE;
+
+                        _fallthrough_; /* to handle empty property */
+                case VALUE:
+                        if (strchr(NEWLINE, uevent[i])) {
+                                uevent[i] = '\0';
+
+                                r = handle_uevent_line(device, key, value, &major, &minor);
+                                if (r < 0)
+                                        log_device_debug_errno(device, r, "sd-device: Failed to handle uevent entry '%s=%s', ignoring: %m", key, value);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                default:
+                        assert_not_reached("Invalid state when parsing uevent file");
+                }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        log_device_debug_errno(device, r, "sd-device: Failed to set 'MAJOR=%s' or 'MINOR=%s' from '%s', ignoring: %m", major, minor, path);
+        }
+
+        return 0;
+}
+
+_public_ int sd_device_get_ifindex(sd_device *device, int *ifindex) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (device->ifindex <= 0)
+                return -ENOENT;
+
+        if (ifindex)
+                *ifindex = device->ifindex;
+
+        return 0;
+}
+
+_public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(id, -EINVAL);
+
+        switch (id[0]) {
+        case 'b':
+        case 'c': {
+                dev_t devt;
+
+                if (isempty(id))
+                        return -EINVAL;
+
+                r = parse_dev(id + 1, &devt);
+                if (r < 0)
+                        return r;
+
+                return sd_device_new_from_devnum(ret, id[0], devt);
+        }
+
+        case 'n': {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                _cleanup_close_ int sk = -1;
+                struct ifreq ifr = {};
+                int ifindex;
+
+                r = parse_ifindex(&id[1], &ifr.ifr_ifindex);
+                if (r < 0)
+                        return r;
+
+                sk = socket_ioctl_fd();
+                if (sk < 0)
+                        return sk;
+
+                r = ioctl(sk, SIOCGIFNAME, &ifr);
+                if (r < 0)
+                        return -errno;
+
+                r = sd_device_new_from_subsystem_sysname(&device, "net", ifr.ifr_name);
+                if (r < 0)
+                        return r;
+
+                r = sd_device_get_ifindex(device, &ifindex);
+                if (r < 0)
+                        return r;
+
+                /* this is racey, so we might end up with the wrong device */
+                if (ifr.ifr_ifindex != ifindex)
+                        return -ENODEV;
+
+                *ret = TAKE_PTR(device);
+                return 0;
+        }
+
+        case '+': {
+                char subsys[PATH_MAX];
+                char *sysname;
+
+                (void) strscpy(subsys, sizeof(subsys), id + 1);
+                sysname = strchr(subsys, ':');
+                if (!sysname)
+                        return -EINVAL;
+
+                sysname[0] = '\0';
+                sysname++;
+
+                return sd_device_new_from_subsystem_sysname(ret, subsys, sysname);
+        }
+
+        default:
+                return -EINVAL;
+        }
+}
+
+_public_ int sd_device_get_syspath(sd_device *device, const char **ret) {
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        assert(path_startswith(device->syspath, "/sys/"));
+
+        *ret = device->syspath;
+
+        return 0;
+}
+
+static int device_new_from_child(sd_device **ret, sd_device *child) {
+        _cleanup_free_ char *path = NULL;
+        const char *subdir, *syspath;
+        int r;
+
+        assert(ret);
+        assert(child);
+
+        r = sd_device_get_syspath(child, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strdup(syspath);
+        if (!path)
+                return -ENOMEM;
+        subdir = path + STRLEN("/sys");
+
+        for (;;) {
+                char *pos;
+
+                pos = strrchr(subdir, '/');
+                if (!pos || pos < subdir + 2)
+                        break;
+
+                *pos = '\0';
+
+                r = sd_device_new_from_syspath(ret, path);
+                if (r < 0)
+                        continue;
+
+                return 0;
+        }
+
+        return -ENODEV;
+}
+
+_public_ int sd_device_get_parent(sd_device *child, sd_device **ret) {
+
+        assert_return(ret, -EINVAL);
+        assert_return(child, -EINVAL);
+
+        if (!child->parent_set) {
+                child->parent_set = true;
+
+                (void) device_new_from_child(&child->parent, child);
+        }
+
+        if (!child->parent)
+                return -ENOENT;
+
+        *ret = child->parent;
+        return 0;
+}
+
+int device_set_subsystem(sd_device *device, const char *_subsystem) {
+        _cleanup_free_ char *subsystem = NULL;
+        int r;
+
+        assert(device);
+        assert(_subsystem);
+
+        subsystem = strdup(_subsystem);
+        if (!subsystem)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "SUBSYSTEM", subsystem);
+        if (r < 0)
+                return r;
+
+        device->subsystem_set = true;
+        return free_and_replace(device->subsystem, subsystem);
+}
+
+static int device_set_drivers_subsystem(sd_device *device, const char *_subsystem) {
+        _cleanup_free_ char *subsystem = NULL;
+        int r;
+
+        assert(device);
+        assert(_subsystem);
+        assert(*_subsystem);
+
+        subsystem = strdup(_subsystem);
+        if (!subsystem)
+                return -ENOMEM;
+
+        r = device_set_subsystem(device, "drivers");
+        if (r < 0)
+                return r;
+
+        return free_and_replace(device->driver_subsystem, subsystem);
+}
+
+_public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
+        const char *syspath, *drivers = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        if (!device->subsystem_set) {
+                _cleanup_free_ char *subsystem = NULL;
+                char *path;
+
+                /* read 'subsystem' link */
+                path = strjoina(syspath, "/subsystem");
+                r = readlink_value(path, &subsystem);
+                if (r >= 0)
+                        r = device_set_subsystem(device, subsystem);
+                /* use implicit names */
+                else if (path_startswith(device->devpath, "/module/"))
+                        r = device_set_subsystem(device, "module");
+                else if (!(drivers = strstr(syspath, "/drivers/")) &&
+                         PATH_STARTSWITH_SET(device->devpath, "/subsystem/",
+                                                              "/class/",
+                                                              "/bus/"))
+                        r = device_set_subsystem(device, "subsystem");
+                if (r < 0 && r != -ENOENT)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem for %s: %m", device->devpath);
+
+                device->subsystem_set = true;
+        } else if (!device->driver_subsystem_set)
+                drivers = strstr(syspath, "/drivers/");
+
+        if (!device->driver_subsystem_set) {
+                if (drivers) {
+                        _cleanup_free_ char *subpath = NULL;
+
+                        subpath = strndup(syspath, drivers - syspath);
+                        if (!subpath)
+                                r = -ENOMEM;
+                        else {
+                                const char *subsys;
+
+                                subsys = strrchr(subpath, '/');
+                                if (!subsys)
+                                        r = -EINVAL;
+                                else
+                                        r = device_set_drivers_subsystem(device, subsys + 1);
+                        }
+                        if (r < 0 && r != -ENOENT)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem for driver %s: %m", device->devpath);
+                }
+
+                device->driver_subsystem_set = true;
+        }
+
+        if (!device->subsystem)
+                return -ENOENT;
+
+        *ret = device->subsystem;
+        return 0;
+}
+
+_public_ int sd_device_get_devtype(sd_device *device, const char **devtype) {
+        int r;
+
+        assert(devtype);
+        assert(device);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (!device->devtype)
+                return -ENOENT;
+
+        *devtype = device->devtype;
+
+        return 0;
+}
+
+_public_ int sd_device_get_parent_with_subsystem_devtype(sd_device *child, const char *subsystem, const char *devtype, sd_device **ret) {
+        sd_device *parent = NULL;
+        int r;
+
+        assert_return(child, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        r = sd_device_get_parent(child, &parent);
+        while (r >= 0) {
+                const char *parent_subsystem = NULL;
+                const char *parent_devtype = NULL;
+
+                (void) sd_device_get_subsystem(parent, &parent_subsystem);
+                if (streq_ptr(parent_subsystem, subsystem)) {
+                        if (!devtype)
+                                break;
+
+                        (void) sd_device_get_devtype(parent, &parent_devtype);
+                        if (streq_ptr(parent_devtype, devtype))
+                                break;
+                }
+                r = sd_device_get_parent(parent, &parent);
+        }
+
+        if (r < 0)
+                return r;
+
+        *ret = parent;
+        return 0;
+}
+
+_public_ int sd_device_get_devnum(sd_device *device, dev_t *devnum) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (major(device->devnum) <= 0)
+                return -ENOENT;
+
+        if (devnum)
+                *devnum = device->devnum;
+
+        return 0;
+}
+
+int device_set_driver(sd_device *device, const char *_driver) {
+        _cleanup_free_ char *driver = NULL;
+        int r;
+
+        assert(device);
+        assert(_driver);
+
+        driver = strdup(_driver);
+        if (!driver)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "DRIVER", driver);
+        if (r < 0)
+                return r;
+
+        device->driver_set = true;
+        return free_and_replace(device->driver, driver);
+}
+
+_public_ int sd_device_get_driver(sd_device *device, const char **ret) {
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->driver_set) {
+                _cleanup_free_ char *driver = NULL;
+                const char *syspath;
+                char *path;
+                int r;
+
+                r = sd_device_get_syspath(device, &syspath);
+                if (r < 0)
+                        return r;
+
+                path = strjoina(syspath, "/driver");
+                r = readlink_value(path, &driver);
+                if (r >= 0) {
+                        r = device_set_driver(device, driver);
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to set driver for %s: %m", device->devpath);
+                } else if (r == -ENOENT)
+                        device->driver_set = true;
+                else
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set driver for %s: %m", device->devpath);
+        }
+
+        if (!device->driver)
+                return -ENOENT;
+
+        *ret = device->driver;
+        return 0;
+}
+
+_public_ int sd_device_get_devpath(sd_device *device, const char **devpath) {
+        assert_return(device, -EINVAL);
+        assert_return(devpath, -EINVAL);
+
+        assert(device->devpath);
+        assert(device->devpath[0] == '/');
+
+        *devpath = device->devpath;
+        return 0;
+}
+
+_public_ int sd_device_get_devname(sd_device *device, const char **devname) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(devname, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (!device->devname)
+                return -ENOENT;
+
+        assert(path_startswith(device->devname, "/dev/"));
+
+        *devname = device->devname;
+        return 0;
+}
+
+static int device_set_sysname(sd_device *device) {
+        _cleanup_free_ char *sysname = NULL;
+        const char *sysnum = NULL;
+        const char *pos;
+        size_t len = 0;
+
+        if (!device->devpath)
+                return -EINVAL;
+
+        pos = strrchr(device->devpath, '/');
+        if (!pos)
+                return -EINVAL;
+        pos++;
+
+        /* devpath is not a root directory */
+        if (*pos == '\0' || pos <= device->devpath)
+                return -EINVAL;
+
+        sysname = strdup(pos);
+        if (!sysname)
+                return -ENOMEM;
+
+        /* some devices have '!' in their name, change that to '/' */
+        while (sysname[len] != '\0') {
+                if (sysname[len] == '!')
+                        sysname[len] = '/';
+
+                len++;
+        }
+
+        /* trailing number */
+        while (len > 0 && isdigit(sysname[--len]))
+                sysnum = &sysname[len];
+
+        if (len == 0)
+                sysnum = NULL;
+
+        device->sysname_set = true;
+        device->sysnum = sysnum;
+        return free_and_replace(device->sysname, sysname);
+}
+
+_public_ int sd_device_get_sysname(sd_device *device, const char **ret) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->sysname_set) {
+                r = device_set_sysname(device);
+                if (r < 0)
+                        return r;
+        }
+
+        assert_return(device->sysname, -ENOENT);
+
+        *ret = device->sysname;
+        return 0;
+}
+
+_public_ int sd_device_get_sysnum(sd_device *device, const char **ret) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->sysname_set) {
+                r = device_set_sysname(device);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!device->sysnum)
+                return -ENOENT;
+
+        *ret = device->sysnum;
+        return 0;
+}
+
+static bool is_valid_tag(const char *tag) {
+        assert(tag);
+
+        return !strchr(tag, ':') && !strchr(tag, ' ');
+}
+
+int device_add_tag(sd_device *device, const char *tag) {
+        int r;
+
+        assert(device);
+        assert(tag);
+
+        if (!is_valid_tag(tag))
+                return -EINVAL;
+
+        r = set_ensure_allocated(&device->tags, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(device->tags, tag);
+        if (r < 0)
+                return r;
+
+        device->tags_generation++;
+        device->property_tags_outdated = true;
+
+        return 0;
+}
+
+int device_add_devlink(sd_device *device, const char *devlink) {
+        int r;
+
+        assert(device);
+        assert(devlink);
+
+        r = set_ensure_allocated(&device->devlinks, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(device->devlinks, devlink);
+        if (r < 0)
+                return r;
+
+        device->devlinks_generation++;
+        device->property_devlinks_outdated = true;
+
+        return 0;
+}
+
+static int device_add_property_internal_from_string(sd_device *device, const char *str) {
+        _cleanup_free_ char *key = NULL;
+        char *value;
+
+        assert(device);
+        assert(str);
+
+        key = strdup(str);
+        if (!key)
+                return -ENOMEM;
+
+        value = strchr(key, '=');
+        if (!value)
+                return -EINVAL;
+
+        *value = '\0';
+
+        if (isempty(++value))
+                value = NULL;
+
+        return device_add_property_internal(device, key, value);
+}
+
+int device_set_usec_initialized(sd_device *device, usec_t when) {
+        char s[DECIMAL_STR_MAX(usec_t)];
+        int r;
+
+        assert(device);
+
+        xsprintf(s, USEC_FMT, when);
+
+        r = device_add_property_internal(device, "USEC_INITIALIZED", s);
+        if (r < 0)
+                return r;
+
+        device->usec_initialized = when;
+        return 0;
+}
+
+static int handle_db_line(sd_device *device, char key, const char *value) {
+        char *path;
+        int r;
+
+        assert(device);
+        assert(value);
+
+        switch (key) {
+        case 'G':
+                r = device_add_tag(device, value);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'S':
+                path = strjoina("/dev/", value);
+                r = device_add_devlink(device, path);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'E':
+                r = device_add_property_internal_from_string(device, value);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'I': {
+                usec_t t;
+
+                r = safe_atou64(value, &t);
+                if (r < 0)
+                        return r;
+
+                r = device_set_usec_initialized(device, t);
+                if (r < 0)
+                        return r;
+
+                break;
+        }
+        case 'L':
+                r = safe_atoi(value, &device->devlink_priority);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'W':
+                r = safe_atoi(value, &device->watch_handle);
+                if (r < 0)
+                        return r;
+
+                break;
+        default:
+                log_device_debug(device, "sd-device: Unknown key '%c' in device db, ignoring", key);
+        }
+
+        return 0;
+}
+
+int device_get_id_filename(sd_device *device, const char **ret) {
+        assert(device);
+        assert(ret);
+
+        if (!device->id_filename) {
+                _cleanup_free_ char *id = NULL;
+                const char *subsystem;
+                dev_t devnum;
+                int ifindex, r;
+
+                r = sd_device_get_subsystem(device, &subsystem);
+                if (r < 0)
+                        return r;
+
+                if (sd_device_get_devnum(device, &devnum) >= 0) {
+                        assert(subsystem);
+
+                        /* use dev_t — b259:131072, c254:0 */
+                        r = asprintf(&id, "%c%u:%u",
+                                     streq(subsystem, "block") ? 'b' : 'c',
+                                     major(devnum), minor(devnum));
+                        if (r < 0)
+                                return -ENOMEM;
+                } else if (sd_device_get_ifindex(device, &ifindex) >= 0) {
+                        /* use netdev ifindex — n3 */
+                        r = asprintf(&id, "n%u", (unsigned) ifindex);
+                        if (r < 0)
+                                return -ENOMEM;
+                } else {
+                        /* use $subsys:$sysname — pci:0000:00:1f.2
+                         * sysname() has '!' translated, get it from devpath
+                         */
+                        const char *sysname;
+
+                        sysname = basename(device->devpath);
+                        if (!sysname)
+                                return -EINVAL;
+
+                        if (!subsystem)
+                                return -EINVAL;
+
+                        if (streq(subsystem, "drivers")) {
+                                /* the 'drivers' pseudo-subsystem is special, and needs the real subsystem
+                                 * encoded as well */
+                                r = asprintf(&id, "+drivers:%s:%s", device->driver_subsystem, sysname);
+                                if (r < 0)
+                                        return -ENOMEM;
+                        } else {
+                                r = asprintf(&id, "+%s:%s", subsystem, sysname);
+                                if (r < 0)
+                                        return -ENOMEM;
+                        }
+                }
+
+                device->id_filename = TAKE_PTR(id);
+        }
+
+        *ret = device->id_filename;
+        return 0;
+}
+
+int device_read_db_internal(sd_device *device, bool force) {
+        _cleanup_free_ char *db = NULL;
+        char *path;
+        const char *id, *value;
+        char key;
+        size_t db_len;
+        unsigned i;
+        int r;
+
+        enum {
+                PRE_KEY,
+                KEY,
+                PRE_VALUE,
+                VALUE,
+                INVALID_LINE,
+        } state = PRE_KEY;
+
+        assert(device);
+
+        if (device->db_loaded || (!force && device->sealed))
+                return 0;
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        r = read_full_file(path, &db, &db_len);
+        if (r < 0) {
+                if (r == -ENOENT)
+                        return 0;
+                else
+                        return log_device_debug_errno(device, r, "sd-device: Failed to read db '%s': %m", path);
+        }
+
+        /* devices with a database entry are initialized */
+        device->is_initialized = true;
+
+        device->db_loaded = true;
+
+        for (i = 0; i < db_len; i++) {
+                switch (state) {
+                case PRE_KEY:
+                        if (!strchr(NEWLINE, db[i])) {
+                                key = db[i];
+
+                                state = KEY;
+                        }
+
+                        break;
+                case KEY:
+                        if (db[i] != ':') {
+                                log_device_debug(device, "sd-device: Invalid db entry with key '%c', ignoring", key);
+
+                                state = INVALID_LINE;
+                        } else {
+                                db[i] = '\0';
+
+                                state = PRE_VALUE;
+                        }
+
+                        break;
+                case PRE_VALUE:
+                        value = &db[i];
+
+                        state = VALUE;
+
+                        break;
+                case INVALID_LINE:
+                        if (strchr(NEWLINE, db[i]))
+                                state = PRE_KEY;
+
+                        break;
+                case VALUE:
+                        if (strchr(NEWLINE, db[i])) {
+                                db[i] = '\0';
+                                r = handle_db_line(device, key, value);
+                                if (r < 0)
+                                        log_device_debug_errno(device, r, "sd-device: Failed to handle db entry '%c:%s', ignoring: %m", key, value);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                default:
+                        assert_not_reached("Invalid state when parsing db");
+                }
+        }
+
+        return 0;
+}
+
+_public_ int sd_device_get_is_initialized(sd_device *device) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        return device->is_initialized;
+}
+
+_public_ int sd_device_get_usec_since_initialized(sd_device *device, uint64_t *usec) {
+        usec_t now_ts;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (!device->is_initialized)
+                return -EBUSY;
+
+        if (!device->usec_initialized)
+                return -ENODATA;
+
+        now_ts = now(clock_boottime_or_monotonic());
+
+        if (now_ts < device->usec_initialized)
+                return -EIO;
+
+        *usec = now_ts - device->usec_initialized;
+        return 0;
+}
+
+_public_ const char *sd_device_get_tag_first(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        device->tags_iterator_generation = device->tags_generation;
+        device->tags_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->tags, &device->tags_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_tag_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        if (device->tags_iterator_generation != device->tags_generation)
+                return NULL;
+
+        (void) set_iterate(device->tags, &device->tags_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_devlink_first(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        device->devlinks_iterator_generation = device->devlinks_generation;
+        device->devlinks_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_devlink_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        if (device->devlinks_iterator_generation != device->devlinks_generation)
+                return NULL;
+
+        (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
+        return v;
+}
+
+int device_properties_prepare(sd_device *device) {
+        int r;
+
+        assert(device);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->property_devlinks_outdated) {
+                _cleanup_free_ char *devlinks = NULL;
+                size_t devlinks_allocated = 0, devlinks_len = 0;
+                const char *devlink;
+
+                for (devlink = sd_device_get_devlink_first(device); devlink; devlink = sd_device_get_devlink_next(device)) {
+                        char *e;
+
+                        if (!GREEDY_REALLOC(devlinks, devlinks_allocated, devlinks_len + strlen(devlink) + 2))
+                                return -ENOMEM;
+                        if (devlinks_len > 0)
+                                stpcpy(devlinks + devlinks_len++, " ");
+                        e = stpcpy(devlinks + devlinks_len, devlink);
+                        devlinks_len = e - devlinks;
+                }
+
+                r = device_add_property_internal(device, "DEVLINKS", devlinks);
+                if (r < 0)
+                        return r;
+
+                device->property_devlinks_outdated = false;
+        }
+
+        if (device->property_tags_outdated) {
+                _cleanup_free_ char *tags = NULL;
+                size_t tags_allocated = 0, tags_len = 0;
+                const char *tag;
+
+                if (!GREEDY_REALLOC(tags, tags_allocated, 2))
+                        return -ENOMEM;
+                stpcpy(tags, ":");
+                tags_len++;
+
+                for (tag = sd_device_get_tag_first(device); tag; tag = sd_device_get_tag_next(device)) {
+                        char *e;
+
+                        if (!GREEDY_REALLOC(tags, tags_allocated, tags_len + strlen(tag) + 2))
+                                return -ENOMEM;
+                        e = stpcpy(stpcpy(tags + tags_len, tag), ":");
+                        tags_len = e - tags;
+                }
+
+                r = device_add_property_internal(device, "TAGS", tags);
+                if (r < 0)
+                        return r;
+
+                device->property_tags_outdated = false;
+        }
+
+        return 0;
+}
+
+_public_ const char *sd_device_get_property_first(sd_device *device, const char **_value) {
+        const char *key;
+        const char *value;
+        int r;
+
+        assert_return(device, NULL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return NULL;
+
+        device->properties_iterator_generation = device->properties_generation;
+        device->properties_iterator = ITERATOR_FIRST;
+
+        ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)&value, (const void**)&key);
+
+        if (_value)
+                *_value = value;
+        return key;
+}
+
+_public_ const char *sd_device_get_property_next(sd_device *device, const char **_value) {
+        const char *key;
+        const char *value;
+        int r;
+
+        assert_return(device, NULL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return NULL;
+
+        if (device->properties_iterator_generation != device->properties_generation)
+                return NULL;
+
+        ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)&value, (const void**)&key);
+
+        if (_value)
+                *_value = value;
+        return key;
+}
+
+static int device_sysattrs_read_all(sd_device *device) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        const char *syspath;
+        struct dirent *dent;
+        int r;
+
+        assert(device);
+
+        if (device->sysattrs_read)
+                return 0;
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        dir = opendir(syspath);
+        if (!dir)
+                return -errno;
+
+        r = set_ensure_allocated(&device->sysattrs, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                char *path;
+                struct stat statbuf;
+
+                /* only handle symlinks and regular files */
+                if (!IN_SET(dent->d_type, DT_LNK, DT_REG))
+                        continue;
+
+                path = strjoina(syspath, "/", dent->d_name);
+
+                if (lstat(path, &statbuf) != 0)
+                        continue;
+
+                if (!(statbuf.st_mode & S_IRUSR))
+                        continue;
+
+                r = set_put_strdup(device->sysattrs, dent->d_name);
+                if (r < 0)
+                        return r;
+        }
+
+        device->sysattrs_read = true;
+
+        return 0;
+}
+
+_public_ const char *sd_device_get_sysattr_first(sd_device *device) {
+        void *v;
+        int r;
+
+        assert_return(device, NULL);
+
+        if (!device->sysattrs_read) {
+                r = device_sysattrs_read_all(device);
+                if (r < 0) {
+                        errno = -r;
+                        return NULL;
+                }
+        }
+
+        device->sysattrs_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_sysattr_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        if (!device->sysattrs_read)
+                return NULL;
+
+        (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
+        return v;
+}
+
+_public_ int sd_device_has_tag(sd_device *device, const char *tag) {
+        assert_return(device, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        (void) device_read_db(device);
+
+        return !!set_contains(device->tags, tag);
+}
+
+_public_ int sd_device_get_property_value(sd_device *device, const char *key, const char **_value) {
+        char *value;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(key, -EINVAL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return r;
+
+        value = ordered_hashmap_get(device->properties, key);
+        if (!value)
+                return -ENOENT;
+
+        if (_value)
+                *_value = value;
+        return 0;
+}
+
+/* replaces the value if it already exists */
+static int device_add_sysattr_value(sd_device *device, const char *_key, char *value) {
+        _cleanup_free_ char *key = NULL;
+        _cleanup_free_ char *value_old = NULL;
+        int r;
+
+        assert(device);
+        assert(_key);
+
+        r = hashmap_ensure_allocated(&device->sysattr_values, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        value_old = hashmap_remove2(device->sysattr_values, _key, (void **)&key);
+        if (!key) {
+                key = strdup(_key);
+                if (!key)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_put(device->sysattr_values, key, value);
+        if (r < 0)
+                return r;
+        TAKE_PTR(key);
+
+        return 0;
+}
+
+static int device_get_sysattr_value(sd_device *device, const char *_key, const char **_value) {
+        const char *key = NULL, *value;
+
+        assert(device);
+        assert(_key);
+
+        value = hashmap_get2(device->sysattr_values, _key, (void **) &key);
+        if (!key)
+                return -ENOENT;
+
+        if (_value)
+                *_value = value;
+        return 0;
+}
+
+/* We cache all sysattr lookups. If an attribute does not exist, it is stored
+ * with a NULL value in the cache, otherwise the returned string is stored */
+_public_ int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value) {
+        _cleanup_free_ char *value = NULL;
+        const char *syspath, *cached_value = NULL;
+        char *path;
+        struct stat statbuf;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        /* look for possibly already cached result */
+        r = device_get_sysattr_value(device, sysattr, &cached_value);
+        if (r != -ENOENT) {
+                if (r < 0)
+                        return r;
+
+                if (!cached_value)
+                        /* we looked up the sysattr before and it did not exist */
+                        return -ENOENT;
+
+                if (_value)
+                        *_value = cached_value;
+
+                return 0;
+        }
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strjoina(syspath, "/", sysattr);
+        r = lstat(path, &statbuf);
+        if (r < 0) {
+                /* remember that we could not access the sysattr */
+                r = device_add_sysattr_value(device, sysattr, NULL);
+                if (r < 0)
+                        return r;
+
+                return -ENOENT;
+        } else if (S_ISLNK(statbuf.st_mode)) {
+                /* Some core links return only the last element of the target path,
+                 * these are just values, the paths should not be exposed. */
+                if (STR_IN_SET(sysattr, "driver", "subsystem", "module")) {
+                        r = readlink_value(path, &value);
+                        if (r < 0)
+                                return r;
+                } else
+                        return -EINVAL;
+        } else if (S_ISDIR(statbuf.st_mode)) {
+                /* skip directories */
+                return -EINVAL;
+        } else if (!(statbuf.st_mode & S_IRUSR)) {
+                /* skip non-readable files */
+                return -EPERM;
+        } else {
+                size_t size;
+
+                /* read attribute value */
+                r = read_full_file(path, &value, &size);
+                if (r < 0)
+                        return r;
+
+                /* drop trailing newlines */
+                while (size > 0 && value[--size] == '\n')
+                        value[size] = '\0';
+        }
+
+        r = device_add_sysattr_value(device, sysattr, value);
+        if (r < 0)
+                return r;
+
+        *_value = TAKE_PTR(value);
+
+        return 0;
+}
+
+static void device_remove_sysattr_value(sd_device *device, const char *_key) {
+        _cleanup_free_ char *key = NULL;
+
+        assert(device);
+        assert(_key);
+
+        free(hashmap_remove2(device->sysattr_values, _key, (void **) &key));
+}
+
+/* set the attribute and save it in the cache. If a NULL value is passed the
+ * attribute is cleared from the cache */
+_public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, const char *_value) {
+        _cleanup_free_ char *value = NULL;
+        const char *syspath, *path;
+        size_t len;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        if (!_value) {
+                device_remove_sysattr_value(device, sysattr);
+                return 0;
+        }
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strjoina(syspath, "/", sysattr);
+
+        len = strlen(_value);
+
+        /* drop trailing newlines */
+        while (len > 0 && _value[len - 1] == '\n')
+                len --;
+
+        /* value length is limited to 4k */
+        if (len > 4096)
+                return -EINVAL;
+
+        value = strndup(_value, len);
+        if (!value)
+                return -ENOMEM;
+
+        r = write_string_file(path, value, WRITE_STRING_FILE_DISABLE_BUFFER | WRITE_STRING_FILE_NOFOLLOW);
+        if (r < 0) {
+                if (r == -ELOOP)
+                        return -EINVAL;
+                if (r == -EISDIR)
+                        return r;
+
+                r = free_and_strdup(&value, "");
+                if (r < 0)
+                        return r;
+
+                r = device_add_sysattr_value(device, sysattr, value);
+                if (r < 0)
+                        return r;
+                TAKE_PTR(value);
+
+                return -ENXIO;
+        }
+
+        r = device_add_sysattr_value(device, sysattr, value);
+        if (r < 0)
+                return r;
+        TAKE_PTR(value);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-sd-device-monitor.c b/src/libsystemd/sd-device/test-sd-device-monitor.c
new file mode 100644
index 0000000..aa1edaa
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device-monitor.c
@@ -0,0 +1,218 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "sd-device.h"
+#include "sd-event.h"
+
+#include "device-monitor-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "macro.h"
+#include "string-util.h"
+#include "tests.h"
+#include "util.h"
+#include "virt.h"
+
+static int monitor_handler(sd_device_monitor *m, sd_device *d, void *userdata) {
+        const char *s, *syspath = userdata;
+
+        assert_se(sd_device_get_syspath(d, &s) >= 0);
+        assert_se(streq(s, syspath));
+
+        return sd_event_exit(sd_device_monitor_get_event(m), 100);
+}
+
+static int test_receive_device_fail(void) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        _cleanup_(sd_device_unrefp) sd_device *loopback = NULL;
+        const char *syspath;
+        int r;
+
+        log_info("/* %s */", __func__);
+
+        /* Try to send device with invalid action and without seqnum. */
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+        assert_se(device_add_property(loopback, "ACTION", "hoge") >= 0);
+
+        assert_se(sd_device_get_syspath(loopback, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        /* Do not use assert_se() here. */
+        r = device_monitor_send_device(monitor_server, monitor_client, loopback);
+        if (r < 0)
+                return log_error_errno(r, "Failed to send loopback device: %m");
+
+        assert_se(sd_event_run(sd_device_monitor_get_event(monitor_client), 0) >= 0);
+
+        return 0;
+}
+
+static void test_send_receive_one(sd_device *device, bool subsystem_filter, bool tag_filter, bool use_bpf) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        const char *syspath, *subsystem, *tag, *devtype = NULL;
+
+        log_device_info(device, "/* %s(subsystem_filter=%s, tag_filter=%s, use_bpf=%s) */", __func__,
+                        true_false(subsystem_filter), true_false(tag_filter), true_false(use_bpf));
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        if (subsystem_filter) {
+                assert_se(sd_device_get_subsystem(device, &subsystem) >= 0);
+                (void) sd_device_get_devtype(device, &devtype);
+                assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, subsystem, devtype) >= 0);
+        }
+
+        if (tag_filter)
+                FOREACH_DEVICE_TAG(device, tag)
+                        assert_se(sd_device_monitor_filter_add_match_tag(monitor_client, tag) >= 0);
+
+        if ((subsystem_filter || tag_filter) && use_bpf)
+                assert_se(sd_device_monitor_filter_update(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_subsystem_filter(sd_device *device) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        const char *syspath, *subsystem, *p, *s;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+        assert_se(sd_device_get_subsystem(device, &subsystem) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, subsystem, NULL) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_add_match_subsystem(e, subsystem, false) >= 0);
+        FOREACH_DEVICE(e, d) {
+                assert_se(sd_device_get_syspath(d, &p) >= 0);
+                assert_se(sd_device_get_subsystem(d, &s) >= 0);
+
+                log_info("Sending device subsystem:%s syspath:%s", s, p);
+                assert_se(device_monitor_send_device(monitor_server, monitor_client, d) >= 0);
+        }
+
+        log_info("Sending device subsystem:%s syspath:%s", subsystem, syspath);
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_sd_device_monitor_filter_remove(sd_device *device) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        const char *syspath;
+
+        log_device_info(device, "/* %s */", __func__);
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, "hoge", NULL) >= 0);
+        assert_se(sd_device_monitor_filter_update(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_run(sd_device_monitor_get_event(monitor_client), 0) >= 0);
+
+        assert_se(sd_device_monitor_filter_remove(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_device_copy_properties(sd_device *device) {
+        _cleanup_(sd_device_unrefp) sd_device *copy = NULL;
+
+        assert_se(device_shallow_clone(device, &copy) >= 0);
+        assert_se(device_copy_properties(copy, device) >= 0);
+
+        test_send_receive_one(copy, false, false, false);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_device_unrefp) sd_device *loopback = NULL, *sda = NULL;
+        int r;
+
+        test_setup_logging(LOG_INFO);
+
+        if (getuid() != 0)
+                return log_tests_skipped("not root");
+
+        r = test_receive_device_fail();
+        if (r < 0) {
+                assert_se(r == -EPERM && detect_container() > 0);
+                return log_tests_skipped("Running in container? Skipping remaining tests");
+        }
+
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+        assert_se(device_add_property(loopback, "ACTION", "add") >= 0);
+        assert_se(device_add_property(loopback, "SEQNUM", "10") >= 0);
+
+        test_send_receive_one(loopback, false, false, false);
+        test_send_receive_one(loopback,  true, false, false);
+        test_send_receive_one(loopback, false,  true, false);
+        test_send_receive_one(loopback,  true,  true, false);
+        test_send_receive_one(loopback,  true, false,  true);
+        test_send_receive_one(loopback, false,  true,  true);
+        test_send_receive_one(loopback,  true,  true,  true);
+
+        test_subsystem_filter(loopback);
+        test_sd_device_monitor_filter_remove(loopback);
+        test_device_copy_properties(loopback);
+
+        r = sd_device_new_from_subsystem_sysname(&sda, "block", "sda");
+        if (r < 0) {
+                log_info_errno(r, "Failed to create sd_device for sda, skipping remaining tests: %m");
+                return 0;
+        }
+
+        assert_se(device_add_property(sda, "ACTION", "change") >= 0);
+        assert_se(device_add_property(sda, "SEQNUM", "11") >= 0);
+
+        test_send_receive_one(sda, false, false, false);
+        test_send_receive_one(sda,  true, false, false);
+        test_send_receive_one(sda, false,  true, false);
+        test_send_receive_one(sda,  true,  true, false);
+        test_send_receive_one(sda,  true, false,  true);
+        test_send_receive_one(sda, false,  true,  true);
+        test_send_receive_one(sda,  true,  true,  true);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-sd-device-thread.c b/src/libsystemd/sd-device/test-sd-device-thread.c
new file mode 100644
index 0000000..9f1c023
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device-thread.c
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-device.h"
+
+#include "device-util.h"
+#include "macro.h"
+
+static void* thread(void *p) {
+        sd_device **d = p;
+
+        assert_se(!(*d = sd_device_unref(*d)));
+
+        return NULL;
+}
+
+int main(int argc, char *argv[]) {
+        sd_device *loopback;
+        pthread_t t;
+        const char *key, *value;
+
+        assert_se(unsetenv("SYSTEMD_MEMPOOL") == 0);
+
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+
+        FOREACH_DEVICE_PROPERTY(loopback, key, value)
+                printf("%s=%s\n", key, value);
+
+        assert_se(pthread_create(&t, NULL, thread, &loopback) == 0);
+        assert_se(pthread_join(t, NULL) == 0);
+
+        assert_se(!loopback);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-sd-device.c b/src/libsystemd/sd-device/test-sd-device.c
new file mode 100644
index 0000000..e459b13
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device.c
@@ -0,0 +1,156 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "device-enumerator-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "hashmap.h"
+#include "string-util.h"
+#include "tests.h"
+#include "util.h"
+
+static void test_sd_device_one(sd_device *d) {
+        const char *syspath, *subsystem, *val;
+        dev_t devnum;
+        usec_t usec;
+        int i, r;
+
+        assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+
+        r = sd_device_get_subsystem(d, &subsystem);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        r = sd_device_get_devtype(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        r = sd_device_get_devnum(d, &devnum);
+        assert_se((r >= 0 && major(devnum) > 0) || r == -ENOENT);
+
+        r = sd_device_get_ifindex(d, &i);
+        assert_se((r >= 0 && i > 0) || r == -ENOENT);
+
+        r = sd_device_get_driver(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        assert_se(sd_device_get_devpath(d, &val) >= 0);
+
+        r = sd_device_get_devname(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        assert_se(sd_device_get_sysname(d, &val) >= 0);
+
+        r = sd_device_get_sysnum(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        i = sd_device_get_is_initialized(d);
+        assert_se(i >= 0);
+        if (i > 0) {
+                r = sd_device_get_usec_since_initialized(d, &usec);
+                assert_se((r >= 0 && usec > 0) || r == -ENODATA);
+        }
+
+        r = sd_device_get_sysattr_value(d, "name_assign_type", &val);
+        assert_se(r >= 0 || IN_SET(r, -ENOENT, -EINVAL));
+
+        r = sd_device_get_property_value(d, "ID_NET_DRIVER", &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        log_info("syspath:%s subsystem:%s initialized:%s", syspath, strna(subsystem), yes_no(i));
+}
+
+static void test_sd_device_enumerator_devices(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_allow_uninitialized(e) >= 0);
+        FOREACH_DEVICE(e, d)
+                test_sd_device_one(d);
+}
+
+static void test_sd_device_enumerator_subsystems(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_allow_uninitialized(e) >= 0);
+        FOREACH_SUBSYSTEM(e, d)
+                test_sd_device_one(d);
+}
+
+static void test_sd_device_enumerator_filter_subsystem_one(const char *subsystem, Hashmap *h) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d, *t;
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_add_match_subsystem(e, subsystem, true) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+                assert_se(t = hashmap_remove(h, syspath));
+                assert_se(!sd_device_unref(t));
+
+                log_debug("Removed subsystem:%s syspath:%s", subsystem, syspath);
+        }
+
+        assert_se(hashmap_isempty(h));
+}
+
+static void test_sd_device_enumerator_filter_subsystem(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        _cleanup_(hashmap_freep) Hashmap *subsystems;
+        sd_device *d;
+        Hashmap *h;
+        char *s;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(subsystems = hashmap_new(&string_hash_ops));
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath, *subsystem;
+                int r;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+
+                r = sd_device_get_subsystem(d, &subsystem);
+                assert_se(r >= 0 || r == -ENOENT);
+                if (r < 0)
+                        continue;
+
+                h = hashmap_get(subsystems, subsystem);
+                if (!h) {
+                        char *str;
+                        assert_se(str = strdup(subsystem));
+                        assert_se(h = hashmap_new(&string_hash_ops));
+                        assert_se(hashmap_put(subsystems, str, h) >= 0);
+                }
+
+                assert_se(hashmap_put(h, syspath, d) >= 0);
+                assert_se(sd_device_ref(d));
+
+                log_debug("Added subsystem:%s syspath:%s", subsystem, syspath);
+        }
+
+        while ((h = hashmap_steal_first_key_and_value(subsystems, (void**) &s))) {
+                test_sd_device_enumerator_filter_subsystem_one(s, h);
+                hashmap_free(h);
+                free(s);
+        }
+}
+
+int main(int argc, char **argv) {
+        test_setup_logging(LOG_INFO);
+
+        test_sd_device_enumerator_devices();
+        test_sd_device_enumerator_subsystems();
+        test_sd_device_enumerator_filter_subsystem();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-udev-device-thread.c b/src/libsystemd/sd-device/test-udev-device-thread.c
new file mode 100644
index 0000000..2fc0f59
--- /dev/null
+++ b/src/libsystemd/sd-device/test-udev-device-thread.c
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libudev.h"
+
+#include "macro.h"
+
+static void* thread(void *p) {
+        struct udev_device **d = p;
+
+        assert_se(!(*d = udev_device_unref(*d)));
+
+        return NULL;
+}
+
+int main(int argc, char *argv[]) {
+        struct udev_device *loopback;
+        pthread_t t;
+
+        assert_se(unsetenv("SYSTEMD_MEMPOOL") == 0);
+
+        assert_se(loopback = udev_device_new_from_syspath(NULL, "/sys/class/net/lo"));
+
+        assert_se(udev_device_get_properties_list_entry(loopback));
+
+        assert_se(pthread_create(&t, NULL, thread, &loopback) == 0);
+        assert_se(pthread_join(t, NULL) == 0);
+
+        assert_se(!loopback);
+
+        return 0;
+}