./move.sh

1 files changed, 1532 insertions, 0 deletions

diff --git a/src/libcore/swap.c b/src/libcore/swap.c
new file mode 100644
index 0000000000..a532b15be8
--- /dev/null
+++ b/src/libcore/swap.c
@@ -0,0 +1,1532 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <sys/epoll.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "libudev.h"
+
+#include "alloc-util.h"
+#include "dbus-swap.h"
+#include "escape.h"
+#include "exit-status.h"
+#include "fd-util.h"
+#include "formats-util.h"
+#include "fstab-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "special.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "swap.h"
+#include "udev-util.h"
+#include "unit-name.h"
+#include "unit.h"
+#include "virt.h"
+
+static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = {
+        [SWAP_DEAD] = UNIT_INACTIVE,
+        [SWAP_ACTIVATING] = UNIT_ACTIVATING,
+        [SWAP_ACTIVATING_DONE] = UNIT_ACTIVE,
+        [SWAP_ACTIVE] = UNIT_ACTIVE,
+        [SWAP_DEACTIVATING] = UNIT_DEACTIVATING,
+        [SWAP_ACTIVATING_SIGTERM] = UNIT_DEACTIVATING,
+        [SWAP_ACTIVATING_SIGKILL] = UNIT_DEACTIVATING,
+        [SWAP_DEACTIVATING_SIGTERM] = UNIT_DEACTIVATING,
+        [SWAP_DEACTIVATING_SIGKILL] = UNIT_DEACTIVATING,
+        [SWAP_FAILED] = UNIT_FAILED
+};
+
+static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata);
+static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
+
+static void swap_unset_proc_swaps(Swap *s) {
+        assert(s);
+
+        if (!s->from_proc_swaps)
+                return;
+
+        s->parameters_proc_swaps.what = mfree(s->parameters_proc_swaps.what);
+
+        s->from_proc_swaps = false;
+}
+
+static int swap_set_devnode(Swap *s, const char *devnode) {
+        Hashmap *swaps;
+        Swap *first;
+        int r;
+
+        assert(s);
+
+        r = hashmap_ensure_allocated(&UNIT(s)->manager->swaps_by_devnode, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        swaps = UNIT(s)->manager->swaps_by_devnode;
+
+        if (s->devnode) {
+                first = hashmap_get(swaps, s->devnode);
+
+                LIST_REMOVE(same_devnode, first, s);
+                if (first)
+                        hashmap_replace(swaps, first->devnode, first);
+                else
+                        hashmap_remove(swaps, s->devnode);
+
+                s->devnode = mfree(s->devnode);
+        }
+
+        if (devnode) {
+                s->devnode = strdup(devnode);
+                if (!s->devnode)
+                        return -ENOMEM;
+
+                first = hashmap_get(swaps, s->devnode);
+                LIST_PREPEND(same_devnode, first, s);
+
+                return hashmap_replace(swaps, first->devnode, first);
+        }
+
+        return 0;
+}
+
+static void swap_init(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+        assert(UNIT(s)->load_state == UNIT_STUB);
+
+        s->timeout_usec = u->manager->default_timeout_start_usec;
+
+        s->exec_context.std_output = u->manager->default_std_output;
+        s->exec_context.std_error = u->manager->default_std_error;
+
+        s->parameters_proc_swaps.priority = s->parameters_fragment.priority = -1;
+
+        s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
+
+        u->ignore_on_isolate = true;
+}
+
+static void swap_unwatch_control_pid(Swap *s) {
+        assert(s);
+
+        if (s->control_pid <= 0)
+                return;
+
+        unit_unwatch_pid(UNIT(s), s->control_pid);
+        s->control_pid = 0;
+}
+
+static void swap_done(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        swap_unset_proc_swaps(s);
+        swap_set_devnode(s, NULL);
+
+        s->what = mfree(s->what);
+        s->parameters_fragment.what = mfree(s->parameters_fragment.what);
+        s->parameters_fragment.options = mfree(s->parameters_fragment.options);
+
+        s->exec_runtime = exec_runtime_unref(s->exec_runtime);
+        exec_command_done_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX);
+        s->control_command = NULL;
+
+        swap_unwatch_control_pid(s);
+
+        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+}
+
+static int swap_arm_timer(Swap *s, usec_t usec) {
+        int r;
+
+        assert(s);
+
+        if (s->timer_event_source) {
+                r = sd_event_source_set_time(s->timer_event_source, usec);
+                if (r < 0)
+                        return r;
+
+                return sd_event_source_set_enabled(s->timer_event_source, SD_EVENT_ONESHOT);
+        }
+
+        if (usec == USEC_INFINITY)
+                return 0;
+
+        r = sd_event_add_time(
+                        UNIT(s)->manager->event,
+                        &s->timer_event_source,
+                        CLOCK_MONOTONIC,
+                        usec, 0,
+                        swap_dispatch_timer, s);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_source_set_description(s->timer_event_source, "swap-timer");
+
+        return 0;
+}
+
+static int swap_add_device_links(Swap *s) {
+        assert(s);
+
+        if (!s->what)
+                return 0;
+
+        if (!s->from_fragment)
+                return 0;
+
+        if (is_device_path(s->what))
+                return unit_add_node_link(UNIT(s), s->what, MANAGER_IS_SYSTEM(UNIT(s)->manager), UNIT_BINDS_TO);
+        else
+                /* File based swap devices need to be ordered after
+                 * systemd-remount-fs.service, since they might need a
+                 * writable file system. */
+                return unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, SPECIAL_REMOUNT_FS_SERVICE, NULL, true);
+}
+
+static int swap_add_default_dependencies(Swap *s) {
+        int r;
+
+        assert(s);
+
+        if (!UNIT(s)->default_dependencies)
+                return 0;
+
+        if (!MANAGER_IS_SYSTEM(UNIT(s)->manager))
+                return 0;
+
+        if (detect_container() > 0)
+                return 0;
+
+        /* swap units generated for the swap dev links are missing the
+         * ordering dep against the swap target. */
+        r = unit_add_dependency_by_name(UNIT(s), UNIT_BEFORE, SPECIAL_SWAP_TARGET, NULL, true);
+        if (r < 0)
+                return r;
+
+        return unit_add_two_dependencies_by_name(UNIT(s), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, NULL, true);
+}
+
+static int swap_verify(Swap *s) {
+        _cleanup_free_ char *e = NULL;
+        int r;
+
+        if (UNIT(s)->load_state != UNIT_LOADED)
+                return 0;
+
+        r = unit_name_from_path(s->what, ".swap", &e);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(s), r, "Failed to generate unit name from path: %m");
+
+        if (!unit_has_name(UNIT(s), e)) {
+                log_unit_error(UNIT(s), "Value of What= and unit name do not match, not loading.");
+                return -EINVAL;
+        }
+
+        if (s->exec_context.pam_name && s->kill_context.kill_mode != KILL_CONTROL_GROUP) {
+                log_unit_error(UNIT(s), "Unit has PAM enabled. Kill mode must be set to 'control-group'. Refusing to load.");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static int swap_load_devnode(Swap *s) {
+        _cleanup_udev_device_unref_ struct udev_device *d = NULL;
+        struct stat st;
+        const char *p;
+
+        assert(s);
+
+        if (stat(s->what, &st) < 0 || !S_ISBLK(st.st_mode))
+                return 0;
+
+        d = udev_device_new_from_devnum(UNIT(s)->manager->udev, 'b', st.st_rdev);
+        if (!d)
+                return 0;
+
+        p = udev_device_get_devnode(d);
+        if (!p)
+                return 0;
+
+        return swap_set_devnode(s, p);
+}
+
+static int swap_load(Unit *u) {
+        int r;
+        Swap *s = SWAP(u);
+
+        assert(s);
+        assert(u->load_state == UNIT_STUB);
+
+        /* Load a .swap file */
+        r = unit_load_fragment_and_dropin_optional(u);
+        if (r < 0)
+                return r;
+
+        if (u->load_state == UNIT_LOADED) {
+
+                if (UNIT(s)->fragment_path)
+                        s->from_fragment = true;
+
+                if (!s->what) {
+                        if (s->parameters_fragment.what)
+                                s->what = strdup(s->parameters_fragment.what);
+                        else if (s->parameters_proc_swaps.what)
+                                s->what = strdup(s->parameters_proc_swaps.what);
+                        else {
+                                r = unit_name_to_path(u->id, &s->what);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (!s->what)
+                                return -ENOMEM;
+                }
+
+                path_kill_slashes(s->what);
+
+                if (!UNIT(s)->description) {
+                        r = unit_set_description(u, s->what);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = unit_require_mounts_for(UNIT(s), s->what);
+                if (r < 0)
+                        return r;
+
+                r = swap_add_device_links(s);
+                if (r < 0)
+                        return r;
+
+                r = swap_load_devnode(s);
+                if (r < 0)
+                        return r;
+
+                r = unit_patch_contexts(u);
+                if (r < 0)
+                        return r;
+
+                r = unit_add_exec_dependencies(u, &s->exec_context);
+                if (r < 0)
+                        return r;
+
+                r = unit_set_default_slice(u);
+                if (r < 0)
+                        return r;
+
+                r = swap_add_default_dependencies(s);
+                if (r < 0)
+                        return r;
+        }
+
+        return swap_verify(s);
+}
+
+static int swap_setup_unit(
+                Manager *m,
+                const char *what,
+                const char *what_proc_swaps,
+                int priority,
+                bool set_flags) {
+
+        _cleanup_free_ char *e = NULL;
+        bool delete = false;
+        Unit *u = NULL;
+        int r;
+        SwapParameters *p;
+
+        assert(m);
+        assert(what);
+        assert(what_proc_swaps);
+
+        r = unit_name_from_path(what, ".swap", &e);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "Failed to generate unit name from path: %m");
+
+        u = manager_get_unit(m, e);
+
+        if (u &&
+            SWAP(u)->from_proc_swaps &&
+            !path_equal(SWAP(u)->parameters_proc_swaps.what, what_proc_swaps)) {
+                log_error("Swap %s appeared twice with different device paths %s and %s", e, SWAP(u)->parameters_proc_swaps.what, what_proc_swaps);
+                return -EEXIST;
+        }
+
+        if (!u) {
+                delete = true;
+
+                u = unit_new(m, sizeof(Swap));
+                if (!u)
+                        return log_oom();
+
+                r = unit_add_name(u, e);
+                if (r < 0)
+                        goto fail;
+
+                SWAP(u)->what = strdup(what);
+                if (!SWAP(u)->what) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                unit_add_to_load_queue(u);
+        } else
+                delete = false;
+
+        p = &SWAP(u)->parameters_proc_swaps;
+
+        if (!p->what) {
+                p->what = strdup(what_proc_swaps);
+                if (!p->what) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        if (set_flags) {
+                SWAP(u)->is_active = true;
+                SWAP(u)->just_activated = !SWAP(u)->from_proc_swaps;
+        }
+
+        SWAP(u)->from_proc_swaps = true;
+
+        p->priority = priority;
+
+        unit_add_to_dbus_queue(u);
+        return 0;
+
+fail:
+        log_unit_warning_errno(u, r, "Failed to load swap unit: %m");
+
+        if (delete && u)
+                unit_free(u);
+
+        return r;
+}
+
+static int swap_process_new(Manager *m, const char *device, int prio, bool set_flags) {
+        _cleanup_udev_device_unref_ struct udev_device *d = NULL;
+        struct udev_list_entry *item = NULL, *first = NULL;
+        const char *dn;
+        struct stat st;
+        int r;
+
+        assert(m);
+
+        r = swap_setup_unit(m, device, device, prio, set_flags);
+        if (r < 0)
+                return r;
+
+        /* If this is a block device, then let's add duplicates for
+         * all other names of this block device */
+        if (stat(device, &st) < 0 || !S_ISBLK(st.st_mode))
+                return 0;
+
+        d = udev_device_new_from_devnum(m->udev, 'b', st.st_rdev);
+        if (!d)
+                return 0;
+
+        /* Add the main device node */
+        dn = udev_device_get_devnode(d);
+        if (dn && !streq(dn, device))
+                swap_setup_unit(m, dn, device, prio, set_flags);
+
+        /* Add additional units for all symlinks */
+        first = udev_device_get_devlinks_list_entry(d);
+        udev_list_entry_foreach(item, first) {
+                const char *p;
+
+                /* Don't bother with the /dev/block links */
+                p = udev_list_entry_get_name(item);
+
+                if (streq(p, device))
+                        continue;
+
+                if (path_startswith(p, "/dev/block/"))
+                        continue;
+
+                if (stat(p, &st) >= 0)
+                        if (!S_ISBLK(st.st_mode) ||
+                            st.st_rdev != udev_device_get_devnum(d))
+                                continue;
+
+                swap_setup_unit(m, p, device, prio, set_flags);
+        }
+
+        return r;
+}
+
+static void swap_set_state(Swap *s, SwapState state) {
+        SwapState old_state;
+        Swap *other;
+
+        assert(s);
+
+        old_state = s->state;
+        s->state = state;
+
+        if (state != SWAP_ACTIVATING &&
+            state != SWAP_ACTIVATING_SIGTERM &&
+            state != SWAP_ACTIVATING_SIGKILL &&
+            state != SWAP_ACTIVATING_DONE &&
+            state != SWAP_DEACTIVATING &&
+            state != SWAP_DEACTIVATING_SIGTERM &&
+            state != SWAP_DEACTIVATING_SIGKILL) {
+                s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+                swap_unwatch_control_pid(s);
+                s->control_command = NULL;
+                s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
+        }
+
+        if (state != old_state)
+                log_unit_debug(UNIT(s), "Changed %s -> %s", swap_state_to_string(old_state), swap_state_to_string(state));
+
+        unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
+
+        /* If there other units for the same device node have a job
+           queued it might be worth checking again if it is runnable
+           now. This is necessary, since swap_start() refuses
+           operation with EAGAIN if there's already another job for
+           the same device node queued. */
+        LIST_FOREACH_OTHERS(same_devnode, other, s)
+                if (UNIT(other)->job)
+                        job_add_to_run_queue(UNIT(other)->job);
+}
+
+static int swap_coldplug(Unit *u) {
+        Swap *s = SWAP(u);
+        SwapState new_state = SWAP_DEAD;
+        int r;
+
+        assert(s);
+        assert(s->state == SWAP_DEAD);
+
+        if (s->deserialized_state != s->state)
+                new_state = s->deserialized_state;
+        else if (s->from_proc_swaps)
+                new_state = SWAP_ACTIVE;
+
+        if (new_state == s->state)
+                return 0;
+
+        if (s->control_pid > 0 &&
+            pid_is_unwaited(s->control_pid) &&
+            IN_SET(new_state,
+                   SWAP_ACTIVATING,
+                   SWAP_ACTIVATING_SIGTERM,
+                   SWAP_ACTIVATING_SIGKILL,
+                   SWAP_ACTIVATING_DONE,
+                   SWAP_DEACTIVATING,
+                   SWAP_DEACTIVATING_SIGTERM,
+                   SWAP_DEACTIVATING_SIGKILL)) {
+
+                r = unit_watch_pid(UNIT(s), s->control_pid);
+                if (r < 0)
+                        return r;
+
+                r = swap_arm_timer(s, usec_add(u->state_change_timestamp.monotonic, s->timeout_usec));
+                if (r < 0)
+                        return r;
+        }
+
+        swap_set_state(s, new_state);
+        return 0;
+}
+
+static void swap_dump(Unit *u, FILE *f, const char *prefix) {
+        Swap *s = SWAP(u);
+        SwapParameters *p;
+
+        assert(s);
+        assert(f);
+
+        if (s->from_proc_swaps)
+                p = &s->parameters_proc_swaps;
+        else if (s->from_fragment)
+                p = &s->parameters_fragment;
+        else
+                p = NULL;
+
+        fprintf(f,
+                "%sSwap State: %s\n"
+                "%sResult: %s\n"
+                "%sWhat: %s\n"
+                "%sFrom /proc/swaps: %s\n"
+                "%sFrom fragment: %s\n",
+                prefix, swap_state_to_string(s->state),
+                prefix, swap_result_to_string(s->result),
+                prefix, s->what,
+                prefix, yes_no(s->from_proc_swaps),
+                prefix, yes_no(s->from_fragment));
+
+        if (s->devnode)
+                fprintf(f, "%sDevice Node: %s\n", prefix, s->devnode);
+
+        if (p)
+                fprintf(f,
+                        "%sPriority: %i\n"
+                        "%sOptions: %s\n",
+                        prefix, p->priority,
+                        prefix, strempty(p->options));
+
+        if (s->control_pid > 0)
+                fprintf(f,
+                        "%sControl PID: "PID_FMT"\n",
+                        prefix, s->control_pid);
+
+        exec_context_dump(&s->exec_context, f, prefix);
+        kill_context_dump(&s->kill_context, f, prefix);
+}
+
+static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
+        pid_t pid;
+        int r;
+        ExecParameters exec_params = {
+                .apply_permissions = true,
+                .apply_chroot      = true,
+                .apply_tty_stdin   = true,
+                .stdin_fd          = -1,
+                .stdout_fd         = -1,
+                .stderr_fd         = -1,
+        };
+
+        assert(s);
+        assert(c);
+        assert(_pid);
+
+        (void) unit_realize_cgroup(UNIT(s));
+        if (s->reset_cpu_usage) {
+                (void) unit_reset_cpu_usage(UNIT(s));
+                s->reset_cpu_usage = false;
+        }
+
+        r = unit_setup_exec_runtime(UNIT(s));
+        if (r < 0)
+                goto fail;
+
+        r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec));
+        if (r < 0)
+                goto fail;
+
+        exec_params.environment = UNIT(s)->manager->environment;
+        exec_params.confirm_spawn = UNIT(s)->manager->confirm_spawn;
+        exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
+        exec_params.cgroup_path = UNIT(s)->cgroup_path;
+        exec_params.cgroup_delegate = s->cgroup_context.delegate;
+        exec_params.runtime_prefix = manager_get_runtime_prefix(UNIT(s)->manager);
+
+        r = exec_spawn(UNIT(s),
+                       c,
+                       &s->exec_context,
+                       &exec_params,
+                       s->exec_runtime,
+                       &pid);
+        if (r < 0)
+                goto fail;
+
+        r = unit_watch_pid(UNIT(s), pid);
+        if (r < 0)
+                /* FIXME: we need to do something here */
+                goto fail;
+
+        *_pid = pid;
+
+        return 0;
+
+fail:
+        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+        return r;
+}
+
+static void swap_enter_dead(Swap *s, SwapResult f) {
+        assert(s);
+
+        if (f != SWAP_SUCCESS)
+                s->result = f;
+
+        exec_runtime_destroy(s->exec_runtime);
+        s->exec_runtime = exec_runtime_unref(s->exec_runtime);
+
+        exec_context_destroy_runtime_directory(&s->exec_context, manager_get_runtime_prefix(UNIT(s)->manager));
+
+        swap_set_state(s, s->result != SWAP_SUCCESS ? SWAP_FAILED : SWAP_DEAD);
+}
+
+static void swap_enter_active(Swap *s, SwapResult f) {
+        assert(s);
+
+        if (f != SWAP_SUCCESS)
+                s->result = f;
+
+        swap_set_state(s, SWAP_ACTIVE);
+}
+
+static void swap_enter_signal(Swap *s, SwapState state, SwapResult f) {
+        int r;
+
+        assert(s);
+
+        if (f != SWAP_SUCCESS)
+                s->result = f;
+
+        r = unit_kill_context(
+                        UNIT(s),
+                        &s->kill_context,
+                        (state != SWAP_ACTIVATING_SIGTERM && state != SWAP_DEACTIVATING_SIGTERM) ?
+                        KILL_KILL : KILL_TERMINATE,
+                        -1,
+                        s->control_pid,
+                        false);
+        if (r < 0)
+                goto fail;
+
+        if (r > 0) {
+                r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec));
+                if (r < 0)
+                        goto fail;
+
+                swap_set_state(s, state);
+        } else if (state == SWAP_ACTIVATING_SIGTERM)
+                swap_enter_signal(s, SWAP_ACTIVATING_SIGKILL, SWAP_SUCCESS);
+        else if (state == SWAP_DEACTIVATING_SIGTERM)
+                swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_SUCCESS);
+        else
+                swap_enter_dead(s, SWAP_SUCCESS);
+
+        return;
+
+fail:
+        log_unit_warning_errno(UNIT(s), r, "Failed to kill processes: %m");
+        swap_enter_dead(s, SWAP_FAILURE_RESOURCES);
+}
+
+static void swap_enter_activating(Swap *s) {
+        _cleanup_free_ char *opts = NULL;
+        int r;
+
+        assert(s);
+
+        s->control_command_id = SWAP_EXEC_ACTIVATE;
+        s->control_command = s->exec_command + SWAP_EXEC_ACTIVATE;
+
+        if (s->from_fragment) {
+                int priority = -1;
+
+                r = fstab_find_pri(s->parameters_fragment.options, &priority);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to parse swap priority \"%s\", ignoring: %m", s->parameters_fragment.options);
+                else if (r == 1 && s->parameters_fragment.priority >= 0)
+                        log_warning("Duplicate swap priority configuration by Priority and Options fields.");
+
+                if (r <= 0 && s->parameters_fragment.priority >= 0) {
+                        if (s->parameters_fragment.options)
+                                r = asprintf(&opts, "%s,pri=%i", s->parameters_fragment.options, s->parameters_fragment.priority);
+                        else
+                                r = asprintf(&opts, "pri=%i", s->parameters_fragment.priority);
+                        if (r < 0)
+                                goto fail;
+                }
+        }
+
+        r = exec_command_set(s->control_command, "/sbin/swapon", NULL);
+        if (r < 0)
+                goto fail;
+
+        if (s->parameters_fragment.options || opts) {
+                r = exec_command_append(s->control_command, "-o",
+                                opts ? : s->parameters_fragment.options, NULL);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = exec_command_append(s->control_command, s->what, NULL);
+        if (r < 0)
+                goto fail;
+
+        swap_unwatch_control_pid(s);
+
+        r = swap_spawn(s, s->control_command, &s->control_pid);
+        if (r < 0)
+                goto fail;
+
+        swap_set_state(s, SWAP_ACTIVATING);
+
+        return;
+
+fail:
+        log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapon' task: %m");
+        swap_enter_dead(s, SWAP_FAILURE_RESOURCES);
+}
+
+static void swap_enter_deactivating(Swap *s) {
+        int r;
+
+        assert(s);
+
+        s->control_command_id = SWAP_EXEC_DEACTIVATE;
+        s->control_command = s->exec_command + SWAP_EXEC_DEACTIVATE;
+
+        r = exec_command_set(s->control_command,
+                             "/sbin/swapoff",
+                             s->what,
+                             NULL);
+        if (r < 0)
+                goto fail;
+
+        swap_unwatch_control_pid(s);
+
+        r = swap_spawn(s, s->control_command, &s->control_pid);
+        if (r < 0)
+                goto fail;
+
+        swap_set_state(s, SWAP_DEACTIVATING);
+
+        return;
+
+fail:
+        log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapoff' task: %m");
+        swap_enter_active(s, SWAP_FAILURE_RESOURCES);
+}
+
+static int swap_start(Unit *u) {
+        Swap *s = SWAP(u), *other;
+        int r;
+
+        assert(s);
+
+        /* We cannot fulfill this request right now, try again later
+         * please! */
+
+        if (s->state == SWAP_DEACTIVATING ||
+            s->state == SWAP_DEACTIVATING_SIGTERM ||
+            s->state == SWAP_DEACTIVATING_SIGKILL ||
+            s->state == SWAP_ACTIVATING_SIGTERM ||
+            s->state == SWAP_ACTIVATING_SIGKILL)
+                return -EAGAIN;
+
+        if (s->state == SWAP_ACTIVATING)
+                return 0;
+
+        assert(s->state == SWAP_DEAD || s->state == SWAP_FAILED);
+
+        if (detect_container() > 0)
+                return -EPERM;
+
+        /* If there's a job for another swap unit for the same node
+         * running, then let's not dispatch this one for now, and wait
+         * until that other job has finished. */
+        LIST_FOREACH_OTHERS(same_devnode, other, s)
+                if (UNIT(other)->job && UNIT(other)->job->state == JOB_RUNNING)
+                        return -EAGAIN;
+
+        r = unit_start_limit_test(u);
+        if (r < 0) {
+                swap_enter_dead(s, SWAP_FAILURE_START_LIMIT_HIT);
+                return r;
+        }
+
+        s->result = SWAP_SUCCESS;
+        s->reset_cpu_usage = true;
+
+        swap_enter_activating(s);
+        return 1;
+}
+
+static int swap_stop(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        if (s->state == SWAP_DEACTIVATING ||
+            s->state == SWAP_DEACTIVATING_SIGTERM ||
+            s->state == SWAP_DEACTIVATING_SIGKILL ||
+            s->state == SWAP_ACTIVATING_SIGTERM ||
+            s->state == SWAP_ACTIVATING_SIGKILL)
+                return 0;
+
+        assert(s->state == SWAP_ACTIVATING ||
+               s->state == SWAP_ACTIVATING_DONE ||
+               s->state == SWAP_ACTIVE);
+
+        if (detect_container() > 0)
+                return -EPERM;
+
+        swap_enter_deactivating(s);
+        return 1;
+}
+
+static int swap_serialize(Unit *u, FILE *f, FDSet *fds) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+        assert(f);
+        assert(fds);
+
+        unit_serialize_item(u, f, "state", swap_state_to_string(s->state));
+        unit_serialize_item(u, f, "result", swap_result_to_string(s->result));
+
+        if (s->control_pid > 0)
+                unit_serialize_item_format(u, f, "control-pid", PID_FMT, s->control_pid);
+
+        if (s->control_command_id >= 0)
+                unit_serialize_item(u, f, "control-command", swap_exec_command_to_string(s->control_command_id));
+
+        return 0;
+}
+
+static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+        assert(fds);
+
+        if (streq(key, "state")) {
+                SwapState state;
+
+                state = swap_state_from_string(value);
+                if (state < 0)
+                        log_unit_debug(u, "Failed to parse state value: %s", value);
+                else
+                        s->deserialized_state = state;
+        } else if (streq(key, "result")) {
+                SwapResult f;
+
+                f = swap_result_from_string(value);
+                if (f < 0)
+                        log_unit_debug(u, "Failed to parse result value: %s", value);
+                else if (f != SWAP_SUCCESS)
+                        s->result = f;
+        } else if (streq(key, "control-pid")) {
+                pid_t pid;
+
+                if (parse_pid(value, &pid) < 0)
+                        log_unit_debug(u, "Failed to parse control-pid value: %s", value);
+                else
+                        s->control_pid = pid;
+
+        } else if (streq(key, "control-command")) {
+                SwapExecCommand id;
+
+                id = swap_exec_command_from_string(value);
+                if (id < 0)
+                        log_unit_debug(u, "Failed to parse exec-command value: %s", value);
+                else {
+                        s->control_command_id = id;
+                        s->control_command = s->exec_command + id;
+                }
+        } else
+                log_unit_debug(u, "Unknown serialization key: %s", key);
+
+        return 0;
+}
+
+_pure_ static UnitActiveState swap_active_state(Unit *u) {
+        assert(u);
+
+        return state_translation_table[SWAP(u)->state];
+}
+
+_pure_ static const char *swap_sub_state_to_string(Unit *u) {
+        assert(u);
+
+        return swap_state_to_string(SWAP(u)->state);
+}
+
+_pure_ static bool swap_check_gc(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        return s->from_proc_swaps;
+}
+
+static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) {
+        Swap *s = SWAP(u);
+        SwapResult f;
+
+        assert(s);
+        assert(pid >= 0);
+
+        if (pid != s->control_pid)
+                return;
+
+        s->control_pid = 0;
+
+        if (is_clean_exit(code, status, NULL))
+                f = SWAP_SUCCESS;
+        else if (code == CLD_EXITED)
+                f = SWAP_FAILURE_EXIT_CODE;
+        else if (code == CLD_KILLED)
+                f = SWAP_FAILURE_SIGNAL;
+        else if (code == CLD_DUMPED)
+                f = SWAP_FAILURE_CORE_DUMP;
+        else
+                assert_not_reached("Unknown code");
+
+        if (f != SWAP_SUCCESS)
+                s->result = f;
+
+        if (s->control_command) {
+                exec_status_exit(&s->control_command->exec_status, &s->exec_context, pid, code, status);
+
+                s->control_command = NULL;
+                s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
+        }
+
+        log_unit_full(u, f == SWAP_SUCCESS ? LOG_DEBUG : LOG_NOTICE, 0,
+                      "Swap process exited, code=%s status=%i", sigchld_code_to_string(code), status);
+
+        switch (s->state) {
+
+        case SWAP_ACTIVATING:
+        case SWAP_ACTIVATING_DONE:
+        case SWAP_ACTIVATING_SIGTERM:
+        case SWAP_ACTIVATING_SIGKILL:
+
+                if (f == SWAP_SUCCESS)
+                        swap_enter_active(s, f);
+                else
+                        swap_enter_dead(s, f);
+                break;
+
+        case SWAP_DEACTIVATING:
+        case SWAP_DEACTIVATING_SIGKILL:
+        case SWAP_DEACTIVATING_SIGTERM:
+
+                swap_enter_dead(s, f);
+                break;
+
+        default:
+                assert_not_reached("Uh, control process died at wrong time.");
+        }
+
+        /* Notify clients about changed exit status */
+        unit_add_to_dbus_queue(u);
+}
+
+static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
+        Swap *s = SWAP(userdata);
+
+        assert(s);
+        assert(s->timer_event_source == source);
+
+        switch (s->state) {
+
+        case SWAP_ACTIVATING:
+        case SWAP_ACTIVATING_DONE:
+                log_unit_warning(UNIT(s), "Activation timed out. Stopping.");
+                swap_enter_signal(s, SWAP_ACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT);
+                break;
+
+        case SWAP_DEACTIVATING:
+                log_unit_warning(UNIT(s), "Deactivation timed out. Stopping.");
+                swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT);
+                break;
+
+        case SWAP_ACTIVATING_SIGTERM:
+                if (s->kill_context.send_sigkill) {
+                        log_unit_warning(UNIT(s), "Activation timed out. Killing.");
+                        swap_enter_signal(s, SWAP_ACTIVATING_SIGKILL, SWAP_FAILURE_TIMEOUT);
+                } else {
+                        log_unit_warning(UNIT(s), "Activation timed out. Skipping SIGKILL. Ignoring.");
+                        swap_enter_dead(s, SWAP_FAILURE_TIMEOUT);
+                }
+                break;
+
+        case SWAP_DEACTIVATING_SIGTERM:
+                if (s->kill_context.send_sigkill) {
+                        log_unit_warning(UNIT(s), "Deactivation timed out. Killing.");
+                        swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_FAILURE_TIMEOUT);
+                } else {
+                        log_unit_warning(UNIT(s), "Deactivation timed out. Skipping SIGKILL. Ignoring.");
+                        swap_enter_dead(s, SWAP_FAILURE_TIMEOUT);
+                }
+                break;
+
+        case SWAP_ACTIVATING_SIGKILL:
+        case SWAP_DEACTIVATING_SIGKILL:
+                log_unit_warning(UNIT(s), "Swap process still around after SIGKILL. Ignoring.");
+                swap_enter_dead(s, SWAP_FAILURE_TIMEOUT);
+                break;
+
+        default:
+                assert_not_reached("Timeout at wrong time.");
+        }
+
+        return 0;
+}
+
+static int swap_load_proc_swaps(Manager *m, bool set_flags) {
+        unsigned i;
+        int r = 0;
+
+        assert(m);
+
+        rewind(m->proc_swaps);
+
+        (void) fscanf(m->proc_swaps, "%*s %*s %*s %*s %*s\n");
+
+        for (i = 1;; i++) {
+                _cleanup_free_ char *dev = NULL, *d = NULL;
+                int prio = 0, k;
+
+                k = fscanf(m->proc_swaps,
+                           "%ms "  /* device/file */
+                           "%*s "  /* type of swap */
+                           "%*s "  /* swap size */
+                           "%*s "  /* used */
+                           "%i\n", /* priority */
+                           &dev, &prio);
+                if (k != 2) {
+                        if (k == EOF)
+                                break;
+
+                        log_warning("Failed to parse /proc/swaps:%u.", i);
+                        continue;
+                }
+
+                if (cunescape(dev, UNESCAPE_RELAX, &d) < 0)
+                        return log_oom();
+
+                device_found_node(m, d, true, DEVICE_FOUND_SWAP, set_flags);
+
+                k = swap_process_new(m, d, prio, set_flags);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+        Manager *m = userdata;
+        Unit *u;
+        int r;
+
+        assert(m);
+        assert(revents & EPOLLPRI);
+
+        r = swap_load_proc_swaps(m, true);
+        if (r < 0) {
+                log_error_errno(r, "Failed to reread /proc/swaps: %m");
+
+                /* Reset flags, just in case, for late calls */
+                LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) {
+                        Swap *swap = SWAP(u);
+
+                        swap->is_active = swap->just_activated = false;
+                }
+
+                return 0;
+        }
+
+        manager_dispatch_load_queue(m);
+
+        LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) {
+                Swap *swap = SWAP(u);
+
+                if (!swap->is_active) {
+                        /* This has just been deactivated */
+
+                        swap_unset_proc_swaps(swap);
+
+                        switch (swap->state) {
+
+                        case SWAP_ACTIVE:
+                                swap_enter_dead(swap, SWAP_SUCCESS);
+                                break;
+
+                        default:
+                                /* Fire again */
+                                swap_set_state(swap, swap->state);
+                                break;
+                        }
+
+                        if (swap->what)
+                                device_found_node(m, swap->what, false, DEVICE_FOUND_SWAP, true);
+
+                } else if (swap->just_activated) {
+
+                        /* New swap entry */
+
+                        switch (swap->state) {
+
+                        case SWAP_DEAD:
+                        case SWAP_FAILED:
+                                swap_enter_active(swap, SWAP_SUCCESS);
+                                break;
+
+                        case SWAP_ACTIVATING:
+                                swap_set_state(swap, SWAP_ACTIVATING_DONE);
+                                break;
+
+                        default:
+                                /* Nothing really changed, but let's
+                                 * issue an notification call
+                                 * nonetheless, in case somebody is
+                                 * waiting for this. */
+                                swap_set_state(swap, swap->state);
+                                break;
+                        }
+                }
+
+                /* Reset the flags for later calls */
+                swap->is_active = swap->just_activated = false;
+        }
+
+        return 1;
+}
+
+static Unit *swap_following(Unit *u) {
+        Swap *s = SWAP(u);
+        Swap *other, *first = NULL;
+
+        assert(s);
+
+        /* If the user configured the swap through /etc/fstab or
+         * a device unit, follow that. */
+
+        if (s->from_fragment)
+                return NULL;
+
+        LIST_FOREACH_OTHERS(same_devnode, other, s)
+                if (other->from_fragment)
+                        return UNIT(other);
+
+        /* Otherwise, make everybody follow the unit that's named after
+         * the swap device in the kernel */
+
+        if (streq_ptr(s->what, s->devnode))
+                return NULL;
+
+        LIST_FOREACH_AFTER(same_devnode, other, s)
+                if (streq_ptr(other->what, other->devnode))
+                        return UNIT(other);
+
+        LIST_FOREACH_BEFORE(same_devnode, other, s) {
+                if (streq_ptr(other->what, other->devnode))
+                        return UNIT(other);
+
+                first = other;
+        }
+
+        /* Fall back to the first on the list */
+        return UNIT(first);
+}
+
+static int swap_following_set(Unit *u, Set **_set) {
+        Swap *s = SWAP(u), *other;
+        Set *set;
+        int r;
+
+        assert(s);
+        assert(_set);
+
+        if (LIST_JUST_US(same_devnode, s)) {
+                *_set = NULL;
+                return 0;
+        }
+
+        set = set_new(NULL);
+        if (!set)
+                return -ENOMEM;
+
+        LIST_FOREACH_OTHERS(same_devnode, other, s) {
+                r = set_put(set, other);
+                if (r < 0)
+                        goto fail;
+        }
+
+        *_set = set;
+        return 1;
+
+fail:
+        set_free(set);
+        return r;
+}
+
+static void swap_shutdown(Manager *m) {
+        assert(m);
+
+        m->swap_event_source = sd_event_source_unref(m->swap_event_source);
+
+        m->proc_swaps = safe_fclose(m->proc_swaps);
+
+        m->swaps_by_devnode = hashmap_free(m->swaps_by_devnode);
+}
+
+static void swap_enumerate(Manager *m) {
+        int r;
+
+        assert(m);
+
+        if (!m->proc_swaps) {
+                m->proc_swaps = fopen("/proc/swaps", "re");
+                if (!m->proc_swaps) {
+                        if (errno == ENOENT)
+                                log_debug("Not swap enabled, skipping enumeration");
+                        else
+                                log_error_errno(errno, "Failed to open /proc/swaps: %m");
+
+                        return;
+                }
+
+                r = sd_event_add_io(m->event, &m->swap_event_source, fileno(m->proc_swaps), EPOLLPRI, swap_dispatch_io, m);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to watch /proc/swaps: %m");
+                        goto fail;
+                }
+
+                /* Dispatch this before we dispatch SIGCHLD, so that
+                 * we always get the events from /proc/swaps before
+                 * the SIGCHLD of /sbin/swapon. */
+                r = sd_event_source_set_priority(m->swap_event_source, -10);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to change /proc/swaps priority: %m");
+                        goto fail;
+                }
+
+                (void) sd_event_source_set_description(m->swap_event_source, "swap-proc");
+        }
+
+        r = swap_load_proc_swaps(m, false);
+        if (r < 0)
+                goto fail;
+
+        return;
+
+fail:
+        swap_shutdown(m);
+}
+
+int swap_process_device_new(Manager *m, struct udev_device *dev) {
+        struct udev_list_entry *item = NULL, *first = NULL;
+        _cleanup_free_ char *e = NULL;
+        const char *dn;
+        Swap *s;
+        int r = 0;
+
+        assert(m);
+        assert(dev);
+
+        dn = udev_device_get_devnode(dev);
+        if (!dn)
+                return 0;
+
+        r = unit_name_from_path(dn, ".swap", &e);
+        if (r < 0)
+                return r;
+
+        s = hashmap_get(m->units, e);
+        if (s)
+                r = swap_set_devnode(s, dn);
+
+        first = udev_device_get_devlinks_list_entry(dev);
+        udev_list_entry_foreach(item, first) {
+                _cleanup_free_ char *n = NULL;
+                int q;
+
+                q = unit_name_from_path(udev_list_entry_get_name(item), ".swap", &n);
+                if (q < 0)
+                        return q;
+
+                s = hashmap_get(m->units, n);
+                if (s) {
+                        q = swap_set_devnode(s, dn);
+                        if (q < 0)
+                                r = q;
+                }
+        }
+
+        return r;
+}
+
+int swap_process_device_remove(Manager *m, struct udev_device *dev) {
+        const char *dn;
+        int r = 0;
+        Swap *s;
+
+        dn = udev_device_get_devnode(dev);
+        if (!dn)
+                return 0;
+
+        while ((s = hashmap_get(m->swaps_by_devnode, dn))) {
+                int q;
+
+                q = swap_set_devnode(s, NULL);
+                if (q < 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+static void swap_reset_failed(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        if (s->state == SWAP_FAILED)
+                swap_set_state(s, SWAP_DEAD);
+
+        s->result = SWAP_SUCCESS;
+}
+
+static int swap_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
+        return unit_kill_common(u, who, signo, -1, SWAP(u)->control_pid, error);
+}
+
+static int swap_get_timeout(Unit *u, usec_t *timeout) {
+        Swap *s = SWAP(u);
+        usec_t t;
+        int r;
+
+        if (!s->timer_event_source)
+                return 0;
+
+        r = sd_event_source_get_time(s->timer_event_source, &t);
+        if (r < 0)
+                return r;
+        if (t == USEC_INFINITY)
+                return 0;
+
+        *timeout = t;
+        return 1;
+}
+
+static bool swap_supported(void) {
+        static int supported = -1;
+
+        /* If swap support is not available in the kernel, or we are
+         * running in a container we don't support swap units, and any
+         * attempts to starting one should fail immediately. */
+
+        if (supported < 0)
+                supported =
+                        access("/proc/swaps", F_OK) >= 0 &&
+                        detect_container() <= 0;
+
+        return supported;
+}
+
+static int swap_control_pid(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        return s->control_pid;
+}
+
+static const char* const swap_exec_command_table[_SWAP_EXEC_COMMAND_MAX] = {
+        [SWAP_EXEC_ACTIVATE] = "ExecActivate",
+        [SWAP_EXEC_DEACTIVATE] = "ExecDeactivate",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(swap_exec_command, SwapExecCommand);
+
+static const char* const swap_result_table[_SWAP_RESULT_MAX] = {
+        [SWAP_SUCCESS] = "success",
+        [SWAP_FAILURE_RESOURCES] = "resources",
+        [SWAP_FAILURE_TIMEOUT] = "timeout",
+        [SWAP_FAILURE_EXIT_CODE] = "exit-code",
+        [SWAP_FAILURE_SIGNAL] = "signal",
+        [SWAP_FAILURE_CORE_DUMP] = "core-dump",
+        [SWAP_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(swap_result, SwapResult);
+
+const UnitVTable swap_vtable = {
+        .object_size = sizeof(Swap),
+        .exec_context_offset = offsetof(Swap, exec_context),
+        .cgroup_context_offset = offsetof(Swap, cgroup_context),
+        .kill_context_offset = offsetof(Swap, kill_context),
+        .exec_runtime_offset = offsetof(Swap, exec_runtime),
+
+        .sections =
+                "Unit\0"
+                "Swap\0"
+                "Install\0",
+        .private_section = "Swap",
+
+        .init = swap_init,
+        .load = swap_load,
+        .done = swap_done,
+
+        .coldplug = swap_coldplug,
+
+        .dump = swap_dump,
+
+        .start = swap_start,
+        .stop = swap_stop,
+
+        .kill = swap_kill,
+
+        .get_timeout = swap_get_timeout,
+
+        .serialize = swap_serialize,
+        .deserialize_item = swap_deserialize_item,
+
+        .active_state = swap_active_state,
+        .sub_state_to_string = swap_sub_state_to_string,
+
+        .check_gc = swap_check_gc,
+
+        .sigchld_event = swap_sigchld_event,
+
+        .reset_failed = swap_reset_failed,
+
+        .control_pid = swap_control_pid,
+
+        .bus_vtable = bus_swap_vtable,
+        .bus_set_property = bus_swap_set_property,
+        .bus_commit_properties = bus_swap_commit_properties,
+
+        .following = swap_following,
+        .following_set = swap_following_set,
+
+        .enumerate = swap_enumerate,
+        .shutdown = swap_shutdown,
+        .supported = swap_supported,
+
+        .status_message_formats = {
+                .starting_stopping = {
+                        [0] = "Activating swap %s...",
+                        [1] = "Deactivating swap %s...",
+                },
+                .finished_start_job = {
+                        [JOB_DONE]       = "Activated swap %s.",
+                        [JOB_FAILED]     = "Failed to activate swap %s.",
+                        [JOB_TIMEOUT]    = "Timed out activating swap %s.",
+                },
+                .finished_stop_job = {
+                        [JOB_DONE]       = "Deactivated swap %s.",
+                        [JOB_FAILED]     = "Failed deactivating swap %s.",
+                        [JOB_TIMEOUT]    = "Timed out deactivating swap %s.",
+                },
+        },
+};