X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fcore%2Fdevice.c;h=6b489a4c9d0a27ae8f9a97d671f31eca78a66f7f;hb=f5b51ea7fcb0b6380c3ceb4d4f3f22f647c6fd32;hp=f2bb656397a4aa85a20cc7b1517466272386523f;hpb=9eb977db5b89b44f254ab40c1876a76b7d7ea2d0;p=elogind.git

diff --git a/src/core/device.c b/src/core/device.c
index f2bb65639..6b489a4c9 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -23,21 +23,25 @@
 #include <sys/epoll.h>
 #include <libudev.h>
 
-#include "unit.h"
-#include "device.h"
-#include "strv.h"
 #include "log.h"
 #include "unit-name.h"
 #include "dbus-device.h"
-#include "def.h"
 #include "path-util.h"
+#include "udev-util.h"
+#include "unit.h"
+#include "swap.h"
+#include "device.h"
 
 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
         [DEVICE_DEAD] = UNIT_INACTIVE,
-        [DEVICE_PLUGGED] = UNIT_ACTIVE
+        [DEVICE_TENTATIVE] = UNIT_ACTIVATING,
+        [DEVICE_PLUGGED] = UNIT_ACTIVE,
 };
 
+static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
+
 static void device_unset_sysfs(Device *d) {
+        Hashmap *devices;
         Device *first;
 
         assert(d);
@@ -47,18 +51,54 @@ static void device_unset_sysfs(Device *d) {
 
         /* Remove this unit from the chain of devices which share the
          * same sysfs path. */
-        first = hashmap_get(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
-        LIST_REMOVE(Device, same_sysfs, first, d);
+        devices = UNIT(d)->manager->devices_by_sysfs;
+        first = hashmap_get(devices, d->sysfs);
+        LIST_REMOVE(same_sysfs, first, d);
 
         if (first)
-                hashmap_remove_and_replace(UNIT(d)->manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
+                hashmap_remove_and_replace(devices, d->sysfs, first->sysfs, first);
         else
-                hashmap_remove(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
+                hashmap_remove(devices, d->sysfs);
 
         free(d->sysfs);
         d->sysfs = NULL;
 }
 
+static int device_set_sysfs(Device *d, const char *sysfs) {
+        Device *first;
+        char *copy;
+        int r;
+
+        assert(d);
+
+        if (streq_ptr(d->sysfs, sysfs))
+                return 0;
+
+        r = hashmap_ensure_allocated(&UNIT(d)->manager->devices_by_sysfs, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        copy = strdup(sysfs);
+        if (!copy)
+                return -ENOMEM;
+
+        device_unset_sysfs(d);
+
+        first = hashmap_get(UNIT(d)->manager->devices_by_sysfs, sysfs);
+        LIST_PREPEND(same_sysfs, first, d);
+
+        r = hashmap_replace(UNIT(d)->manager->devices_by_sysfs, copy, first);
+        if (r < 0) {
+                LIST_REMOVE(same_sysfs, first, d);
+                free(copy);
+                return r;
+        }
+
+        d->sysfs = copy;
+
+        return 0;
+}
+
 static void device_init(Unit *u) {
         Device *d = DEVICE(u);
 
@@ -70,10 +110,10 @@ static void device_init(Unit *u) {
          * indefinitely for plugged in devices, something which cannot
          * happen for the other units since their operations time out
          * anyway. */
-        UNIT(d)->job_timeout = DEFAULT_TIMEOUT_USEC;
+        u->job_timeout = u->manager->default_timeout_start_usec;
 
-        UNIT(d)->ignore_on_isolate = true;
-        UNIT(d)->ignore_on_snapshot = true;
+        u->ignore_on_isolate = true;
+        u->ignore_on_snapshot = true;
 }
 
 static void device_done(Unit *u) {
@@ -92,22 +132,27 @@ static void device_set_state(Device *d, DeviceState state) {
         d->state = state;
 
         if (state != old_state)
-                log_debug("%s changed %s -> %s",
-                          UNIT(d)->id,
-                          device_state_to_string(old_state),
-                          device_state_to_string(state));
+                log_unit_debug(UNIT(d)->id,
+                               "%s changed %s -> %s", UNIT(d)->id,
+                               device_state_to_string(old_state),
+                               device_state_to_string(state));
 
         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
 }
 
-static int device_coldplug(Unit *u) {
+static int device_coldplug(Unit *u, Hashmap *deferred_work) {
         Device *d = DEVICE(u);
 
         assert(d);
         assert(d->state == DEVICE_DEAD);
 
-        if (d->sysfs)
+        if (d->found & DEVICE_FOUND_UDEV)
+                /* If udev says the device is around, it's around */
                 device_set_state(d, DEVICE_PLUGGED);
+        else if (d->found != DEVICE_NOT_FOUND)
+                /* If a device is found in /proc/self/mountinfo or
+                 * /proc/swaps, it's "tentatively" around. */
+                device_set_state(d, DEVICE_TENTATIVE);
 
         return 0;
 }
@@ -124,86 +169,131 @@ static void device_dump(Unit *u, FILE *f, const char *prefix) {
                 prefix, strna(d->sysfs));
 }
 
-static UnitActiveState device_active_state(Unit *u) {
+_pure_ static UnitActiveState device_active_state(Unit *u) {
         assert(u);
 
         return state_translation_table[DEVICE(u)->state];
 }
 
-static const char *device_sub_state_to_string(Unit *u) {
+_pure_ static const char *device_sub_state_to_string(Unit *u) {
         assert(u);
 
         return device_state_to_string(DEVICE(u)->state);
 }
 
-static int device_add_escaped_name(Unit *u, const char *dn) {
-        char *e;
+static int device_update_description(Unit *u, struct udev_device *dev, const char *path) {
+        const char *model;
         int r;
 
         assert(u);
-        assert(dn);
-        assert(dn[0] == '/');
+        assert(dev);
+        assert(path);
 
-        if (!(e = unit_name_from_path(dn, ".device")))
-                return -ENOMEM;
+        model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE");
+        if (!model)
+                model = udev_device_get_property_value(dev, "ID_MODEL");
 
-        r = unit_add_name(u, e);
-        free(e);
+        if (model) {
+                const char *label;
 
-        if (r < 0 && r != -EEXIST)
-                return r;
+                /* Try to concatenate the device model string with a label, if there is one */
+                label = udev_device_get_property_value(dev, "ID_FS_LABEL");
+                if (!label)
+                        label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NAME");
+                if (!label)
+                        label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NUMBER");
 
-        return 0;
+                if (label) {
+                        _cleanup_free_ char *j;
+
+                        j = strjoin(model, " ", label, NULL);
+                        if (j)
+                                r = unit_set_description(u, j);
+                        else
+                                r = -ENOMEM;
+                } else
+                        r = unit_set_description(u, model);
+        } else
+                r = unit_set_description(u, path);
+
+        if (r < 0)
+                log_unit_error_errno(u->id, r, "Failed to set device description: %m");
+
+        return r;
 }
 
-static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
-        char *e;
-        Unit *u;
+static int device_add_udev_wants(Unit *u, struct udev_device *dev) {
+        const char *wants;
+        const char *word, *state;
+        size_t l;
+        int r;
+        const char *property;
 
-        assert(m);
-        assert(dn);
-        assert(dn[0] == '/');
-        assert(_u);
+        assert(u);
+        assert(dev);
 
-        if (!(e = unit_name_from_path(dn, ".device")))
-                return -ENOMEM;
+        property = u->manager->running_as == SYSTEMD_USER ? "SYSTEMD_USER_WANTS" : "SYSTEMD_WANTS";
+        wants = udev_device_get_property_value(dev, property);
+        if (!wants)
+                return 0;
 
-        u = manager_get_unit(m, e);
-        free(e);
+        FOREACH_WORD_QUOTED(word, l, wants, state) {
+                _cleanup_free_ char *n = NULL;
+                char e[l+1];
+
+                memcpy(e, word, l);
+                e[l] = 0;
 
-        if (u) {
-                *_u = u;
-                return 1;
+                n = unit_name_mangle(e, MANGLE_NOGLOB);
+                if (!n)
+                        return log_oom();
+
+                r = unit_add_dependency_by_name(u, UNIT_WANTS, n, NULL, true);
+                if (r < 0)
+                        return log_unit_error_errno(u->id, r, "Failed to add wants dependency: %m");
         }
+        if (!isempty(state))
+                log_unit_warning(u->id, "Property %s on %s has trailing garbage, ignoring.", property, strna(udev_device_get_syspath(dev)));
 
         return 0;
 }
 
-static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
-        const char *sysfs, *model;
+static int device_setup_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
+        _cleanup_free_ char *e = NULL;
+        const char *sysfs;
         Unit *u = NULL;
-        int r;
         bool delete;
+        int r;
 
         assert(m);
+        assert(dev);
+        assert(path);
 
-        if (!(sysfs = udev_device_get_syspath(dev)))
-                return -ENOMEM;
+        sysfs = udev_device_get_syspath(dev);
+        if (!sysfs)
+                return 0;
 
-        if ((r = device_find_escape_name(m, path, &u)) < 0)
-                return r;
+        e = unit_name_from_path(path, ".device");
+        if (!e)
+                return log_oom();
 
-        if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
+        u = manager_get_unit(m, e);
+
+        if (u &&
+            DEVICE(u)->sysfs &&
+            !path_equal(DEVICE(u)->sysfs, sysfs)) {
+                log_unit_error(u->id, "Device %s appeared twice with different sysfs paths %s and %s", e, DEVICE(u)->sysfs, sysfs);
                 return -EEXIST;
+        }
 
         if (!u) {
                 delete = true;
 
                 u = unit_new(m, sizeof(Device));
                 if (!u)
-                        return -ENOMEM;
+                        return log_oom();
 
-                r = device_add_escaped_name(u, path);
+                r = unit_add_name(u, e);
                 if (r < 0)
                         goto fail;
 
@@ -215,75 +305,25 @@ static int device_update_unit(Manager *m, struct udev_device *dev, const char *p
          * actually been seen yet ->sysfs will not be
          * initialized. Hence initialize it if necessary. */
 
-        if (!DEVICE(u)->sysfs) {
-                Device *first;
-
-                if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
-                        r = -ENOMEM;
-                        goto fail;
-                }
-
-                if (!m->devices_by_sysfs)
-                        if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
-                                r = -ENOMEM;
-                                goto fail;
-                        }
-
-                first = hashmap_get(m->devices_by_sysfs, sysfs);
-                LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
-
-                if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
-                        goto fail;
-        }
-
-        if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
-            (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
-                if ((r = unit_set_description(u, model)) < 0)
-                        goto fail;
-        } else
-                if ((r = unit_set_description(u, path)) < 0)
-                        goto fail;
-
-        if (main) {
-                /* The additional systemd udev properties we only
-                 * interpret for the main object */
-                const char *wants, *alias;
-
-                if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
-                        if (!is_path(alias))
-                                log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
-                        else {
-                                if ((r = device_add_escaped_name(u, alias)) < 0)
-                                        goto fail;
-                        }
-                }
-
-                if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
-                        char *state, *w;
-                        size_t l;
-
-                        FOREACH_WORD_QUOTED(w, l, wants, state) {
-                                char *e;
+        r = device_set_sysfs(DEVICE(u), sysfs);
+        if (r < 0)
+                goto fail;
 
-                                if (!(e = strndup(w, l))) {
-                                        r = -ENOMEM;
-                                        goto fail;
-                                }
+        (void) device_update_description(u, dev, path);
 
-                                r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
-                                free(e);
+        /* The additional systemd udev properties we only interpret
+         * for the main object */
+        if (main)
+                (void) device_add_udev_wants(u, dev);
 
-                                if (r < 0)
-                                        goto fail;
-                        }
-                }
-        }
+        /* Note that this won't dispatch the load queue, the caller
+         * has to do that if needed and appropriate */
 
         unit_add_to_dbus_queue(u);
         return 0;
 
 fail:
-        log_warning("Failed to load device unit: %s", strerror(-r));
+        log_unit_warning_errno(u->id, r, "Failed to set up device unit: %m");
 
         if (delete && u)
                 unit_free(u);
@@ -291,21 +331,26 @@ fail:
         return r;
 }
 
-static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
-        const char *sysfs, *dn;
+static int device_process_new(Manager *m, struct udev_device *dev) {
+        const char *sysfs, *dn, *alias;
         struct udev_list_entry *item = NULL, *first = NULL;
+        int r;
 
         assert(m);
 
-        if (!(sysfs = udev_device_get_syspath(dev)))
-                return -ENOMEM;
+        sysfs = udev_device_get_syspath(dev);
+        if (!sysfs)
+                return 0;
 
         /* Add the main unit named after the sysfs path */
-        device_update_unit(m, dev, sysfs, true);
+        r = device_setup_unit(m, dev, sysfs, true);
+        if (r < 0)
+                return r;
 
         /* Add an additional unit for the device node */
-        if ((dn = udev_device_get_devnode(dev)))
-                device_update_unit(m, dev, dn, false);
+        dn = udev_device_get_devnode(dev);
+        if (dn)
+                (void) device_setup_unit(m, dev, dn, false);
 
         /* Add additional units for all symlinks */
         first = udev_device_get_devlinks_list_entry(dev);
@@ -326,64 +371,111 @@ static int device_process_new_device(Manager *m, struct udev_device *dev, bool u
                  * same /dev/disk/by-label/xxx link because they have
                  * the same label. We want to make sure that the same
                  * device that won the symlink wins in systemd, so we
-                 * check the device node major/minor*/
+                 * check the device node major/minor */
                 if (stat(p, &st) >= 0)
                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
                             st.st_rdev != udev_device_get_devnum(dev))
                                 continue;
 
-                device_update_unit(m, dev, p, false);
+                (void) device_setup_unit(m, dev, p, false);
         }
 
-        if (update_state) {
-                Device *d, *l;
+        /* Add additional units for all explicitly configured
+         * aliases */
+        alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
+        if (alias) {
+                const char *word, *state;
+                size_t l;
 
-                manager_dispatch_load_queue(m);
+                FOREACH_WORD_QUOTED(word, l, alias, state) {
+                        char e[l+1];
 
-                l = hashmap_get(m->devices_by_sysfs, sysfs);
-                LIST_FOREACH(same_sysfs, d, l)
-                        device_set_state(d, DEVICE_PLUGGED);
+                        memcpy(e, word, l);
+                        e[l] = 0;
+
+                        if (path_is_absolute(e))
+                                (void) device_setup_unit(m, dev, e, false);
+                        else
+                                log_warning("SYSTEMD_ALIAS for %s is not an absolute path, ignoring: %s", sysfs, e);
+                }
+                if (!isempty(state))
+                        log_warning("SYSTEMD_ALIAS for %s has trailing garbage, ignoring.", sysfs);
         }
 
         return 0;
 }
 
-static int device_process_path(Manager *m, const char *path, bool update_state) {
-        int r;
-        struct udev_device *dev;
+static void device_update_found_one(Device *d, bool add, DeviceFound found, bool now) {
+        DeviceFound n;
 
-        assert(m);
-        assert(path);
+        assert(d);
 
-        if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
-                log_warning("Failed to get udev device object from udev for path %s.", path);
-                return -ENOMEM;
+        n = add ? (d->found | found) : (d->found & ~found);
+        if (n == d->found)
+                return;
+
+        d->found = n;
+
+        if (now) {
+                if (d->found & DEVICE_FOUND_UDEV)
+                        device_set_state(d, DEVICE_PLUGGED);
+                else if (d->found != DEVICE_NOT_FOUND)
+                        device_set_state(d, DEVICE_TENTATIVE);
+                else
+                        device_set_state(d, DEVICE_DEAD);
         }
+}
 
-        r = device_process_new_device(m, dev, update_state);
-        udev_device_unref(dev);
-        return r;
+static int device_update_found_by_sysfs(Manager *m, const char *sysfs, bool add, DeviceFound found, bool now) {
+        Device *d, *l;
+
+        assert(m);
+        assert(sysfs);
+
+        if (found == DEVICE_NOT_FOUND)
+                return 0;
+
+        l = hashmap_get(m->devices_by_sysfs, sysfs);
+        LIST_FOREACH(same_sysfs, d, l)
+                device_update_found_one(d, add, found, now);
+
+        return 0;
 }
 
-static int device_process_removed_device(Manager *m, struct udev_device *dev) {
-        const char *sysfs;
-        Device *d;
+static int device_update_found_by_name(Manager *m, const char *path, bool add, DeviceFound found, bool now) {
+        _cleanup_free_ char *e = NULL;
+        Unit *u;
 
         assert(m);
-        assert(dev);
+        assert(path);
 
-        if (!(sysfs = udev_device_get_syspath(dev)))
-                return -ENOMEM;
+        if (found == DEVICE_NOT_FOUND)
+                return 0;
 
-        /* Remove all units of this sysfs path */
-        while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
-                device_unset_sysfs(d);
-                device_set_state(d, DEVICE_DEAD);
-        }
+        e = unit_name_from_path(path, ".device");
+        if (!e)
+                return log_oom();
+
+        u = manager_get_unit(m, e);
+        if (!u)
+                return 0;
 
+        device_update_found_one(DEVICE(u), add, found, now);
         return 0;
 }
 
+static bool device_is_ready(struct udev_device *dev) {
+        const char *ready;
+
+        assert(dev);
+
+        ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
+        if (!ready)
+                return true;
+
+        return parse_boolean(ready) != 0;
+}
+
 static Unit *device_following(Unit *u) {
         Device *d = DEVICE(u);
         Device *other, *first = NULL;
@@ -408,69 +500,67 @@ static Unit *device_following(Unit *u) {
         return UNIT(first);
 }
 
-static int device_following_set(Unit *u, Set **_s) {
-        Device *d = DEVICE(u);
-        Device *other;
-        Set *s;
+static int device_following_set(Unit *u, Set **_set) {
+        Device *d = DEVICE(u), *other;
+        Set *set;
         int r;
 
         assert(d);
-        assert(_s);
+        assert(_set);
 
-        if (!d->same_sysfs_prev && !d->same_sysfs_next) {
-                *_s = NULL;
+        if (LIST_JUST_US(same_sysfs, d)) {
+                *_set = NULL;
                 return 0;
         }
 
-        if (!(s = set_new(NULL, NULL)))
+        set = set_new(NULL);
+        if (!set)
                 return -ENOMEM;
 
-        for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
-                if ((r = set_put(s, other)) < 0)
+        LIST_FOREACH_AFTER(same_sysfs, other, d) {
+                r = set_put(set, other);
+                if (r < 0)
                         goto fail;
+        }
 
-        for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev)
-                if ((r = set_put(s, other)) < 0)
+        LIST_FOREACH_BEFORE(same_sysfs, other, d) {
+                r = set_put(set, other);
+                if (r < 0)
                         goto fail;
+        }
 
-        *_s = s;
+        *_set = set;
         return 1;
 
 fail:
-        set_free(s);
+        set_free(set);
         return r;
 }
 
 static void device_shutdown(Manager *m) {
         assert(m);
 
+        m->udev_event_source = sd_event_source_unref(m->udev_event_source);
+
         if (m->udev_monitor) {
                 udev_monitor_unref(m->udev_monitor);
                 m->udev_monitor = NULL;
         }
 
-        if (m->udev) {
-                udev_unref(m->udev);
-                m->udev = NULL;
-        }
-
         hashmap_free(m->devices_by_sysfs);
         m->devices_by_sysfs = NULL;
 }
 
 static int device_enumerate(Manager *m) {
-        struct epoll_event ev;
-        int r;
-        struct udev_enumerate *e = NULL;
+        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
         struct udev_list_entry *item = NULL, *first = NULL;
+        int r;
 
         assert(m);
 
-        if (!m->udev) {
-                if (!(m->udev = udev_new()))
-                        return -ENOMEM;
-
-                if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
+        if (!m->udev_monitor) {
+                m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev");
+                if (!m->udev_monitor) {
                         r = -ENOMEM;
                         goto fail;
                 }
@@ -480,112 +570,208 @@ static int device_enumerate(Manager *m) {
                  * during boot. */
                 udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);
 
-                if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
-                        r = -ENOMEM;
+                r = udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd");
+                if (r < 0)
                         goto fail;
-                }
 
-                if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
-                        r = -EIO;
+                r = udev_monitor_enable_receiving(m->udev_monitor);
+                if (r < 0)
                         goto fail;
-                }
 
-                m->udev_watch.type = WATCH_UDEV;
-                m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
-
-                zero(ev);
-                ev.events = EPOLLIN;
-                ev.data.ptr = &m->udev_watch;
-
-                if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
-                        return -errno;
+                r = sd_event_add_io(m->event, &m->udev_event_source, udev_monitor_get_fd(m->udev_monitor), EPOLLIN, device_dispatch_io, m);
+                if (r < 0)
+                        goto fail;
         }
 
-        if (!(e = udev_enumerate_new(m->udev))) {
+        e = udev_enumerate_new(m->udev);
+        if (!e) {
                 r = -ENOMEM;
                 goto fail;
         }
-        if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
-                r = -EIO;
+
+        r = udev_enumerate_add_match_tag(e, "systemd");
+        if (r < 0)
                 goto fail;
-        }
 
-        if (udev_enumerate_scan_devices(e) < 0) {
-                r = -EIO;
+        r = udev_enumerate_add_match_is_initialized(e);
+        if (r < 0)
+                goto fail;
+
+        r = udev_enumerate_scan_devices(e);
+        if (r < 0)
                 goto fail;
-        }
 
         first = udev_enumerate_get_list_entry(e);
-        udev_list_entry_foreach(item, first)
-                device_process_path(m, udev_list_entry_get_name(item), false);
+        udev_list_entry_foreach(item, first) {
+                _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
+                const char *sysfs;
+
+                sysfs = udev_list_entry_get_name(item);
+
+                dev = udev_device_new_from_syspath(m->udev, sysfs);
+                if (!dev) {
+                        log_oom();
+                        continue;
+                }
+
+                if (!device_is_ready(dev))
+                        continue;
+
+                (void) device_process_new(m, dev);
+
+                device_update_found_by_sysfs(m, sysfs, true, DEVICE_FOUND_UDEV, false);
+        }
 
-        udev_enumerate_unref(e);
         return 0;
 
 fail:
-        if (e)
-                udev_enumerate_unref(e);
+        log_error_errno(r, "Failed to enumerate devices: %m");
 
         device_shutdown(m);
         return r;
 }
 
-void device_fd_event(Manager *m, int events) {
-        struct udev_device *dev;
+static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+        _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
+        Manager *m = userdata;
+        const char *action, *sysfs;
         int r;
-        const char *action, *ready;
 
         assert(m);
 
-        if (events != EPOLLIN) {
+        if (revents != EPOLLIN) {
                 static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);
 
                 if (!ratelimit_test(&limit))
-                        log_error("Failed to get udev event: %m");
-                if (!(events & EPOLLIN))
-                        return;
+                        log_error_errno(errno, "Failed to get udev event: %m");
+                if (!(revents & EPOLLIN))
+                        return 0;
         }
 
-        if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
-                /*
-                 * libudev might filter-out devices which pass the bloom filter,
-                 * so getting NULL here is not necessarily an error
-                 */
-                return;
+        /*
+         * libudev might filter-out devices which pass the bloom
+         * filter, so getting NULL here is not necessarily an error.
+         */
+        dev = udev_monitor_receive_device(m->udev_monitor);
+        if (!dev)
+                return 0;
+
+        sysfs = udev_device_get_syspath(dev);
+        if (!sysfs) {
+                log_error("Failed to get udev sys path.");
+                return 0;
         }
 
-        if (!(action = udev_device_get_action(dev))) {
+        action = udev_device_get_action(dev);
+        if (!action) {
                 log_error("Failed to get udev action string.");
-                goto fail;
+                return 0;
         }
 
-        ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
+        if (streq(action, "remove"))  {
+                r = swap_process_device_remove(m, dev);
+                if (r < 0)
+                        log_error_errno(r, "Failed to process swap device remove event: %m");
+
+                /* If we get notified that a device was removed by
+                 * udev, then it's completely gone, hence unset all
+                 * found bits */
+                device_update_found_by_sysfs(m, sysfs, false, DEVICE_FOUND_UDEV|DEVICE_FOUND_MOUNT|DEVICE_FOUND_SWAP, true);
+
+        } else if (device_is_ready(dev)) {
+
+                (void) device_process_new(m, dev);
+
+                r = swap_process_device_new(m, dev);
+                if (r < 0)
+                        log_error_errno(r, "Failed to process swap device new event: %m");
+
+                manager_dispatch_load_queue(m);
+
+                /* The device is found now, set the udev found bit */
+                device_update_found_by_sysfs(m, sysfs, true, DEVICE_FOUND_UDEV, true);
 
-        if (streq(action, "remove") || (ready && parse_boolean(ready) == 0)) {
-                if ((r = device_process_removed_device(m, dev)) < 0) {
-                        log_error("Failed to process udev device event: %s", strerror(-r));
-                        goto fail;
-                }
         } else {
-                if ((r = device_process_new_device(m, dev, true)) < 0) {
-                        log_error("Failed to process udev device event: %s", strerror(-r));
-                        goto fail;
+                /* The device is nominally around, but not ready for
+                 * us. Hence unset the udev bit, but leave the rest
+                 * around. */
+
+                device_update_found_by_sysfs(m, sysfs, false, DEVICE_FOUND_UDEV, true);
+        }
+
+        return 0;
+}
+
+static bool device_supported(Manager *m) {
+        static int read_only = -1;
+        assert(m);
+
+        /* If /sys is read-only we don't support device units, and any
+         * attempts to start one should fail immediately. */
+
+        if (read_only < 0)
+                read_only = path_is_read_only_fs("/sys");
+
+        return read_only <= 0;
+}
+
+int device_found_node(Manager *m, const char *node, bool add, DeviceFound found, bool now) {
+        _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
+        struct stat st;
+
+        assert(m);
+        assert(node);
+
+        /* This is called whenever we find a device referenced in
+         * /proc/swaps or /proc/self/mounts. Such a device might be
+         * mounted/enabled at a time where udev has not finished
+         * probing it yet, and we thus haven't learned about it
+         * yet. In this case we will set the device unit to
+         * "tentative" state. */
+
+        if (add) {
+                if (!path_startswith(node, "/dev"))
+                        return 0;
+
+                if (stat(node, &st) < 0) {
+                        if (errno == ENOENT)
+                                return 0;
+
+                        return log_error_errno(errno, "Failed to stat device node file %s: %m", node);
+                }
+
+                if (!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode))
+                        return 0;
+
+                dev = udev_device_new_from_devnum(m->udev, S_ISBLK(st.st_mode) ? 'b' : 'c', st.st_rdev);
+                if (!dev) {
+                        if (errno == ENOENT)
+                                return 0;
+
+                        return log_oom();
                 }
+
+                /* If the device is known in the kernel and newly
+                 * appeared, then we'll create a device unit for it,
+                 * under the name referenced in /proc/swaps or
+                 * /proc/self/mountinfo. */
+
+                (void) device_setup_unit(m, dev, node, false);
         }
 
-fail:
-        udev_device_unref(dev);
+        /* Update the device unit's state, should it exist */
+        return device_update_found_by_name(m, node, add, found, now);
 }
 
 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
         [DEVICE_DEAD] = "dead",
-        [DEVICE_PLUGGED] = "plugged"
+        [DEVICE_TENTATIVE] = "tentative",
+        [DEVICE_PLUGGED] = "plugged",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 
 const UnitVTable device_vtable = {
-        .suffix = ".device",
         .object_size = sizeof(Device),
         .sections =
                 "Unit\0"
@@ -595,9 +781,9 @@ const UnitVTable device_vtable = {
         .no_instances = true,
 
         .init = device_init,
-
-        .load = unit_load_fragment_and_dropin_optional,
         .done = device_done,
+        .load = unit_load_fragment_and_dropin_optional,
+
         .coldplug = device_coldplug,
 
         .dump = device_dump,
@@ -606,12 +792,22 @@ const UnitVTable device_vtable = {
         .sub_state_to_string = device_sub_state_to_string,
 
         .bus_interface = "org.freedesktop.systemd1.Device",
-        .bus_message_handler = bus_device_message_handler,
-        .bus_invalidating_properties =  bus_device_invalidating_properties,
+        .bus_vtable = bus_device_vtable,
 
         .following = device_following,
         .following_set = device_following_set,
 
         .enumerate = device_enumerate,
-        .shutdown = device_shutdown
+        .shutdown = device_shutdown,
+        .supported = device_supported,
+
+        .status_message_formats = {
+                .starting_stopping = {
+                        [0] = "Expecting device %s...",
+                },
+                .finished_start_job = {
+                        [JOB_DONE]       = "Found device %s.",
+                        [JOB_TIMEOUT]    = "Timed out waiting for device %s.",
+                },
+        },
 };