/***
  This file is part of systemd.

  Copyright 2013 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 <string.h>
#include <unistd.h>

#include <systemd/sd-daemon.h>

#include "basic/alloc-util.h"
#include "bus-error.h"
#include "shared/bus-util.h"
#include "basic/cgroup-util.h"
#include "basic/dirent-util.h"
#include "basic/fd-util.h"
#include "basic/formats-util.h"
#include "basic/hostname-util.h"
#include "basic/label.h"
#include "shared/machine-image.h"
#include "machined.h"
#include "basic/signal-util.h"

Manager *manager_new(void) {
        Manager *m;
        int r;

        m = new0(Manager, 1);
        if (!m)
                return NULL;

        m->machines = hashmap_new(&string_hash_ops);
        m->machine_units = hashmap_new(&string_hash_ops);
        m->machine_leaders = hashmap_new(NULL);

        if (!m->machines || !m->machine_units || !m->machine_leaders) {
                manager_free(m);
                return NULL;
        }

        r = sd_event_default(&m->event);
        if (r < 0) {
                manager_free(m);
                return NULL;
        }

        sd_event_set_watchdog(m->event, true);

        return m;
}

void manager_free(Manager *m) {
        Machine *machine;
        Image *i;

        assert(m);

        while (m->operations)
                operation_free(m->operations);

        assert(m->n_operations == 0);

        while ((machine = hashmap_first(m->machines)))
                machine_free(machine);

        hashmap_free(m->machines);
        hashmap_free(m->machine_units);
        hashmap_free(m->machine_leaders);

        while ((i = hashmap_steal_first(m->image_cache)))
                image_unref(i);

        hashmap_free(m->image_cache);

        sd_event_source_unref(m->image_cache_defer_event);

        bus_verify_polkit_async_registry_free(m->polkit_registry);

        sd_bus_unref(m->bus);
        sd_event_unref(m->event);

        free(m);
}

static int manager_add_host_machine(Manager *m) {
        _cleanup_free_ char *rd = NULL, *unit = NULL;
        sd_id128_t mid;
        Machine *t;
        int r;

        if (m->host_machine)
                return 0;

        r = sd_id128_get_machine(&mid);
        if (r < 0)
                return log_error_errno(r, "Failed to get machine ID: %m");

        rd = strdup("/");
        if (!rd)
                return log_oom();

        unit = strdup("-.slice");
        if (!unit)
                return log_oom();

        t = machine_new(m, MACHINE_HOST, ".host");
        if (!t)
                return log_oom();

        t->leader = 1;
        t->id = mid;

        t->root_directory = rd;
        t->unit = unit;
        rd = unit = NULL;

        dual_timestamp_from_boottime_or_monotonic(&t->timestamp, 0);

        m->host_machine = t;

        return 0;
}

int manager_enumerate_machines(Manager *m) {
        _cleanup_closedir_ DIR *d = NULL;
        struct dirent *de;
        int r = 0;

        assert(m);

        r = manager_add_host_machine(m);
        if (r < 0)
                return r;

        /* Read in machine data stored on disk */
        d = opendir("/run/systemd/machines");
        if (!d) {
                if (errno == ENOENT)
                        return 0;

                return log_error_errno(errno, "Failed to open /run/systemd/machines: %m");
        }

        FOREACH_DIRENT(de, d, return -errno) {
                struct Machine *machine;
                int k;

                if (!dirent_is_file(de))
                        continue;

                /* Ignore symlinks that map the unit name to the machine */
                if (startswith(de->d_name, "unit:"))
                        continue;

                if (!machine_name_is_valid(de->d_name))
                        continue;

                k = manager_add_machine(m, de->d_name, &machine);
                if (k < 0) {
                        r = log_error_errno(k, "Failed to add machine by file name %s: %m", de->d_name);
                        continue;
                }

                machine_add_to_gc_queue(machine);

                k = machine_load(machine);
                if (k < 0)
                        r = k;
        }

        return r;
}

static int manager_connect_bus(Manager *m) {
        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
        int r;

        assert(m);
        assert(!m->bus);

        r = sd_bus_default_system(&m->bus);
        if (r < 0)
                return log_error_errno(r, "Failed to connect to system bus: %m");

        r = sd_bus_add_object_vtable(m->bus, NULL, "/org/freedesktop/machine1", "org.freedesktop.machine1.Manager", manager_vtable, m);
        if (r < 0)
                return log_error_errno(r, "Failed to add manager object vtable: %m");

        r = sd_bus_add_fallback_vtable(m->bus, NULL, "/org/freedesktop/machine1/machine", "org.freedesktop.machine1.Machine", machine_vtable, machine_object_find, m);
        if (r < 0)
                return log_error_errno(r, "Failed to add machine object vtable: %m");

        r = sd_bus_add_node_enumerator(m->bus, NULL, "/org/freedesktop/machine1/machine", machine_node_enumerator, m);
        if (r < 0)
                return log_error_errno(r, "Failed to add machine enumerator: %m");

        r = sd_bus_add_fallback_vtable(m->bus, NULL, "/org/freedesktop/machine1/image", "org.freedesktop.machine1.Image", image_vtable, image_object_find, m);
        if (r < 0)
                return log_error_errno(r, "Failed to add image object vtable: %m");

        r = sd_bus_add_node_enumerator(m->bus, NULL, "/org/freedesktop/machine1/image", image_node_enumerator, m);
        if (r < 0)
                return log_error_errno(r, "Failed to add image enumerator: %m");

        r = sd_bus_add_match(m->bus,
                             NULL,
                             "type='signal',"
                             "sender='org.freedesktop.systemd1',"
                             "interface='org.freedesktop.systemd1.Manager',"
                             "member='JobRemoved',"
                             "path='/org/freedesktop/systemd1'",
                             match_job_removed,
                             m);
        if (r < 0)
                return log_error_errno(r, "Failed to add match for JobRemoved: %m");

        r = sd_bus_add_match(m->bus,
                             NULL,
                             "type='signal',"
                             "sender='org.freedesktop.systemd1',"
                             "interface='org.freedesktop.systemd1.Manager',"
                             "member='UnitRemoved',"
                             "path='/org/freedesktop/systemd1'",
                             match_unit_removed,
                             m);
        if (r < 0)
                return log_error_errno(r, "Failed to add match for UnitRemoved: %m");

        r = sd_bus_add_match(m->bus,
                             NULL,
                             "type='signal',"
                             "sender='org.freedesktop.systemd1',"
                             "interface='org.freedesktop.DBus.Properties',"
                             "member='PropertiesChanged',"
                             "arg0='org.freedesktop.systemd1.Unit'",
                             match_properties_changed,
                             m);
        if (r < 0)
                return log_error_errno(r, "Failed to add match for PropertiesChanged: %m");

        r = sd_bus_add_match(m->bus,
                             NULL,
                             "type='signal',"
                             "sender='org.freedesktop.systemd1',"
                             "interface='org.freedesktop.systemd1.Manager',"
                             "member='Reloading',"
                             "path='/org/freedesktop/systemd1'",
                             match_reloading,
                             m);
        if (r < 0)
                return log_error_errno(r, "Failed to add match for Reloading: %m");

        r = sd_bus_call_method(
                        m->bus,
                        "org.freedesktop.systemd1",
                        "/org/freedesktop/systemd1",
                        "org.freedesktop.systemd1.Manager",
                        "Subscribe",
                        &error,
                        NULL, NULL);
        if (r < 0) {
                log_error("Failed to enable subscription: %s", bus_error_message(&error, r));
                return r;
        }

        r = sd_bus_request_name(m->bus, "org.freedesktop.machine1", 0);
        if (r < 0)
                return log_error_errno(r, "Failed to register name: %m");

        r = sd_bus_attach_event(m->bus, m->event, 0);
        if (r < 0)
                return log_error_errno(r, "Failed to attach bus to event loop: %m");

        return 0;
}

void manager_gc(Manager *m, bool drop_not_started) {
        Machine *machine;

        assert(m);

        while ((machine = m->machine_gc_queue)) {
                LIST_REMOVE(gc_queue, m->machine_gc_queue, machine);
                machine->in_gc_queue = false;

                /* First, if we are not closing yet, initiate stopping */
                if (!machine_check_gc(machine, drop_not_started) &&
                    machine_get_state(machine) != MACHINE_CLOSING)
                        machine_stop(machine);

                /* Now, the stop stop probably made this referenced
                 * again, but if it didn't, then it's time to let it
                 * go entirely. */
                if (!machine_check_gc(machine, drop_not_started)) {
                        machine_finalize(machine);
                        machine_free(machine);
                }
        }
}

int manager_startup(Manager *m) {
        Machine *machine;
        Iterator i;
        int r;

        assert(m);

        /* Connect to the bus */
        r = manager_connect_bus(m);
        if (r < 0)
                return r;

        /* Deserialize state */
        manager_enumerate_machines(m);

        /* Remove stale objects before we start them */
        manager_gc(m, false);

        /* And start everything */
        HASHMAP_FOREACH(machine, m->machines, i)
                machine_start(machine, NULL, NULL);

        return 0;
}

static bool check_idle(void *userdata) {
        Manager *m = userdata;

        if (m->operations)
                return false;

        manager_gc(m, true);

        return hashmap_isempty(m->machines);
}

int manager_run(Manager *m) {
        assert(m);

        return bus_event_loop_with_idle(
                        m->event,
                        m->bus,
                        "org.freedesktop.machine1",
                        DEFAULT_EXIT_USEC,
                        check_idle, m);
}

int main(int argc, char *argv[]) {
        Manager *m = NULL;
        int r;

        log_set_target(LOG_TARGET_AUTO);
        log_set_facility(LOG_AUTH);
        log_parse_environment();
        log_open();

        umask(0022);

        if (argc != 1) {
                log_error("This program takes no arguments.");
                r = -EINVAL;
                goto finish;
        }

        /* Always create the directories people can create inotify
         * watches in. Note that some applications might check for the
         * existence of /run/systemd/machines/ to determine whether
         * machined is available, so please always make sure this
         * check stays in. */
        mkdir_label("/run/systemd/machines", 0755);

        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGCHLD, -1) >= 0);

        m = manager_new();
        if (!m) {
                r = log_oom();
                goto finish;
        }

        r = manager_startup(m);
        if (r < 0) {
                log_error_errno(r, "Failed to fully start up daemon: %m");
                goto finish;
        }

        log_debug("systemd-machined running as pid "PID_FMT, getpid());

        sd_notify(false,
                  "READY=1\n"
                  "STATUS=Processing requests...");

        r = manager_run(m);

        log_debug("systemd-machined stopped as pid "PID_FMT, getpid());

finish:
        manager_free(m);

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}