/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  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 General Public License as published by
  the Free Software Foundation; either version 2 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <dbus/dbus.h>

#include <errno.h>
#include <string.h>
#include <unistd.h>

#include "util.h"
#include "strv.h"
#include "dbus-common.h"

#define INTROSPECTION                                                   \
        DBUS_INTROSPECT_1_0_XML_DOCTYPE_DECL_NODE                       \
        "<node>\n"                                                      \
        " <interface name=\"org.freedesktop.hostname1\">\n"             \
        "  <property name=\"Hostname\" type=\"s\" access=\"read\"/>\n"  \
        "  <property name=\"StaticHostname\" type=\"s\" access=\"read\"/>\n" \
        "  <property name=\"PrettyHostname\" type=\"s\" access=\"read\"/>\n" \
        "  <property name=\"IconName\" type=\"s\" access=\"read\"/>\n"  \
        "  <method name=\"SetHostname\">\n"                             \
        "   <arg name=\"name\" type=\"s\" direction=\"in\"/>\n"         \
        "   <arg name=\"user_interaction\" type=\"b\" direction=\"in\"/>\n" \
        "  </method>\n"                                                 \
        "  <method name=\"SetStaticHostname\">\n"                       \
        "   <arg name=\"name\" type=\"s\" direction=\"in\"/>\n"         \
        "   <arg name=\"user_interaction\" type=\"b\" direction=\"in\"/>\n" \
        "  </method>\n"                                                 \
        "  <method name=\"SetPrettyHostname\">\n"                       \
        "   <arg name=\"name\" type=\"s\" direction=\"in\"/>\n"         \
        "   <arg name=\"user_interaction\" type=\"b\" direction=\"in\"/>\n" \
        "  </method>\n"                                                 \
        "  <method name=\"SetIconName\">\n"                             \
        "   <arg name=\"name\" type=\"s\" direction=\"in\"/>\n"         \
        "   <arg name=\"user_interaction\" type=\"b\" direction=\"in\"/>\n" \
        "  </method>\n"                                                 \
        " </interface>\n"                                               \
        BUS_PROPERTIES_INTERFACE                                        \
        BUS_INTROSPECTABLE_INTERFACE                                    \
        BUS_PEER_INTERFACE                                              \
        "</node>\n"

#define INTERFACES_LIST                         \
        BUS_GENERIC_INTERFACES_LIST             \
        "org.freedesktop.hostname1\0"

enum {
        PROP_HOSTNAME,
        PROP_STATIC_HOSTNAME,
        PROP_PRETTY_HOSTNAME,
        PROP_ICON_NAME,
        _PROP_MAX
};

static char *data[_PROP_MAX] = {
        NULL,
        NULL,
        NULL,
        NULL
};

static void free_data(void) {
        int p;

        for (p = 0; p < _PROP_MAX; p++) {
                free(data[p]);
                data[p] = NULL;
        }
}

static int read_data(void) {
        int r;

        free_data();

        data[PROP_HOSTNAME] = gethostname_malloc();
        if (!data[PROP_HOSTNAME])
                return -ENOMEM;

        r = read_one_line_file("/etc/hostname", &data[PROP_STATIC_HOSTNAME]);
        if (r < 0 && r != -ENOENT)
                return r;

        r = parse_env_file("/etc/machine-info", NEWLINE,
                           "PRETTY_HOSTNAME", &data[PROP_PRETTY_HOSTNAME],
                           "ICON_NAME", &data[PROP_ICON_NAME],
                           NULL);
        if (r < 0 && r != -ENOENT)
                return r;

        return 0;
}

static const char* fallback_icon_name(void) {

#if defined(__i386__) || defined(__x86_64__)
        int r;
        char *type;
        unsigned t;
#endif

        if (detect_virtualization(NULL) > 0)
                return "computer-vm";

#if defined(__i386__) || defined(__x86_64__)
        r = read_one_line_file("/sys/class/dmi/id/chassis_type", &type);
        if (r < 0)
                return NULL;

        r = safe_atou(type, &t);
        free(type);

        if (r < 0)
                return NULL;

        /* We only list the really obvious cases here. The DMI data is
           unreliable enough, so let's not do any additional guesswork
           on top of that. */

        switch (t) {

        case 0x3:
        case 0x4:
        case 0x6:
        case 0x7:
                return "computer-desktop";

        case 0x9:
        case 0xA:
        case 0xE:
                return "computer-laptop";

        case 0x11:
                return "computer-server";
        }

#endif
        return NULL;
}

static int write_data_hostname(void) {
        const char *hn;

        if (isempty(data[PROP_HOSTNAME]))
                hn = "localhost";
        else
                hn = data[PROP_HOSTNAME];

        if (sethostname(hn, strlen(hn)) < 0)
                return -errno;

        return 0;
}

static int write_data_static_hostname(void) {

        if (isempty(data[PROP_STATIC_HOSTNAME])) {

                if (unlink("/etc/hostname") < 0)
                        return errno == ENOENT ? 0 : -errno;

                return 0;
        }

        return write_one_line_file("/etc/hostname", data[PROP_STATIC_HOSTNAME]);
}

static int write_data_other(void) {
        static const char * const name[_PROP_MAX] = {
                [PROP_PRETTY_HOSTNAME] = "PRETTY_HOSTNAME",
                [PROP_ICON_NAME] = "ICON_NAME"
        };

        char **l = NULL;
        int r, p;

        r = load_env_file("/etc/machine-info", &l);
        if (r < 0 && r != -ENOENT)
                return r;

        for (p = 2; p < _PROP_MAX; p++) {
                char *t, **u;

                assert(name[p]);

                if (isempty(data[p]))  {
                        l = strv_env_unset(l, name[p]);
                        continue;
                }

                if (asprintf(&t, "%s=%s", name[p], strempty(data[p])) < 0) {
                        strv_free(l);
                        return -ENOMEM;
                }

                u = strv_env_set(l, t);
                free(t);
                strv_free(l);

                if (!u)
                        return -ENOMEM;
                l = u;
        }

        if (strv_isempty(l)) {

                if (unlink("/etc/machine-info") < 0)
                        return errno == ENOENT ? 0 : -errno;

                return 0;
        }

        r = write_env_file("/etc/machine-info", l);
        strv_free(l);

        return r;
}

/* This mimics dbus_bus_get_unix_user() */
static pid_t get_unix_process_id(
                DBusConnection *connection,
                const char *name,
                DBusError *error) {

        DBusMessage *m = NULL, *reply = NULL;
        uint32_t pid = 0;

        m = dbus_message_new_method_call(
                        DBUS_SERVICE_DBUS,
                        DBUS_PATH_DBUS,
                        DBUS_INTERFACE_DBUS,
                        "GetConnectionUnixProcessID");
        if (!m) {
                dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
                goto finish;
        }

        if (!dbus_message_append_args(
                            m,
                            DBUS_TYPE_STRING, &name,
                            DBUS_TYPE_INVALID)) {
                dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
                goto finish;
        }

        reply = dbus_connection_send_with_reply_and_block(connection, m, -1, error);
        if (!reply)
                goto finish;

        if (dbus_set_error_from_message(error, reply))
                goto finish;

        if (!dbus_message_get_args(
                            reply, error,
                            DBUS_TYPE_UINT32, &pid,
                            DBUS_TYPE_INVALID))
                goto finish;

finish:
        if (m)
                dbus_message_unref(m);

        if (reply)
                dbus_message_unref(reply);

        return (pid_t) pid;
}

static int verify_polkit(
                DBusConnection *c,
                DBusMessage *request,
                const char *action,
                bool interactive,
                DBusError *error) {

        DBusMessage *m = NULL, *reply = NULL;
        const char *unix_process = "unix-process", *pid = "pid", *starttime = "start-time", *cancel_id = "";
        const char *sender;
        uint32_t flags = interactive ? 1 : 0;
        pid_t pid_raw;
        uint32_t pid_u32;
        unsigned long long starttime_raw;
        uint64_t starttime_u64;
        DBusMessageIter iter_msg, iter_struct, iter_array, iter_dict, iter_variant;
        int r;
        dbus_bool_t authorized = FALSE;

        assert(c);
        assert(request);

        sender = dbus_message_get_sender(request);
        if (!sender)
                return -EINVAL;

        pid_raw = get_unix_process_id(c, sender, error);
        if (pid_raw == 0)
                return -EINVAL;

        r = get_starttime_of_pid(pid_raw, &starttime_raw);
        if (r < 0)
                return r;

        m = dbus_message_new_method_call(
                        "org.freedesktop.PolicyKit1",
                        "/org/freedesktop/PolicyKit1/Authority",
                        "org.freedesktop.PolicyKit1.Authority",
                        "CheckAuthorization");
        if (!m)
                return -ENOMEM;

        dbus_message_iter_init_append(m, &iter_msg);

        pid_u32 = (uint32_t) pid_raw;
        starttime_u64 = (uint64_t) starttime_raw;

        if (!dbus_message_iter_open_container(&iter_msg, DBUS_TYPE_STRUCT, NULL, &iter_struct) ||
            !dbus_message_iter_append_basic(&iter_struct, DBUS_TYPE_STRING, &unix_process) ||
            !dbus_message_iter_open_container(&iter_struct, DBUS_TYPE_ARRAY, "{sv}", &iter_array) ||
            !dbus_message_iter_open_container(&iter_array, DBUS_TYPE_DICT_ENTRY, NULL, &iter_dict) ||
            !dbus_message_iter_append_basic(&iter_dict, DBUS_TYPE_STRING, &pid) ||
            !dbus_message_iter_open_container(&iter_dict, DBUS_TYPE_VARIANT, "u", &iter_variant) ||
            !dbus_message_iter_append_basic(&iter_variant, DBUS_TYPE_UINT32, &pid_u32) ||
            !dbus_message_iter_close_container(&iter_dict, &iter_variant) ||
            !dbus_message_iter_close_container(&iter_array, &iter_dict) ||
            !dbus_message_iter_open_container(&iter_array, DBUS_TYPE_DICT_ENTRY, NULL, &iter_dict) ||
            !dbus_message_iter_append_basic(&iter_dict, DBUS_TYPE_STRING, &starttime) ||
            !dbus_message_iter_open_container(&iter_dict, DBUS_TYPE_VARIANT, "t", &iter_variant) ||
            !dbus_message_iter_append_basic(&iter_variant, DBUS_TYPE_UINT64, &starttime_u64) ||
            !dbus_message_iter_close_container(&iter_dict, &iter_variant) ||
            !dbus_message_iter_close_container(&iter_array, &iter_dict) ||
            !dbus_message_iter_close_container(&iter_struct, &iter_array) ||
            !dbus_message_iter_close_container(&iter_msg, &iter_struct) ||
            !dbus_message_iter_append_basic(&iter_msg, DBUS_TYPE_STRING, &action) ||
            !dbus_message_iter_open_container(&iter_msg, DBUS_TYPE_ARRAY, "{ss}", &iter_array) ||
            !dbus_message_iter_close_container(&iter_msg, &iter_array) ||
            !dbus_message_iter_append_basic(&iter_msg, DBUS_TYPE_UINT32, &flags) ||
            !dbus_message_iter_append_basic(&iter_msg, DBUS_TYPE_STRING, &cancel_id)) {
                r = -ENOMEM;
                goto finish;
        }

        reply = dbus_connection_send_with_reply_and_block(c, m, -1, error);
        if (!reply) {
                r = -EIO;
                goto finish;
        }

        if (dbus_set_error_from_message(error, reply)) {
                r = -EIO;
                goto finish;
        }

        if (!dbus_message_iter_init(reply, &iter_msg) ||
            dbus_message_iter_get_arg_type(&iter_msg) != DBUS_TYPE_STRUCT) {
                r = -EIO;
                goto finish;
        }

        dbus_message_iter_recurse(&iter_msg, &iter_struct);

        if (dbus_message_iter_get_arg_type(&iter_struct) != DBUS_TYPE_BOOLEAN) {
                r = -EIO;
                goto finish;
        }

        dbus_message_iter_get_basic(&iter_struct, &authorized);

        r = authorized ? 0 : -EPERM;

finish:

        if (m)
                dbus_message_unref(m);

        if (reply)
                dbus_message_unref(reply);

        return r;
}

static int bus_hostname_append_icon_name(DBusMessageIter *i, const char *property, void *userdata) {
        const char *name;

        assert(i);
        assert(property);

        if (isempty(data[PROP_ICON_NAME]))
                name = fallback_icon_name();
        else
                name = data[PROP_ICON_NAME];

        return bus_property_append_string(i, property, (void*) name);
}

static DBusHandlerResult hostname_message_handler(
                DBusConnection *connection,
                DBusMessage *message,
                void *userdata) {

        const BusProperty properties[] = {
                { "org.freedesktop.hostname1", "Hostname",       bus_property_append_string,    "s", data[PROP_HOSTNAME]},
                { "org.freedesktop.hostname1", "StaticHostname", bus_property_append_string,    "s", data[PROP_STATIC_HOSTNAME]},
                { "org.freedesktop.hostname1", "PrettyHostname", bus_property_append_string,    "s", data[PROP_PRETTY_HOSTNAME]},
                { "org.freedesktop.hostname1", "IconName",       bus_hostname_append_icon_name, "s", data[PROP_ICON_NAME]},
                { NULL, NULL, NULL, NULL, NULL }
        };

        DBusMessage *reply = NULL, *changed = NULL;
        DBusError error;
        int r;

        assert(connection);
        assert(message);

        dbus_error_init(&error);

        if (dbus_message_is_method_call(message, "org.freedesktop.hostname1", "SetHostname")) {
                const char *name;
                dbus_bool_t interactive;

                if (!dbus_message_get_args(
                                    message,
                                    &error,
                                    DBUS_TYPE_STRING, &name,
                                    DBUS_TYPE_BOOLEAN, &interactive,
                                    DBUS_TYPE_INVALID))
                        return bus_send_error_reply(connection, message, &error, -EINVAL);

                if (isempty(name))
                        name = data[PROP_STATIC_HOSTNAME];

                if (isempty(name))
                        name = "localhost";

                if (!hostname_is_valid(name))
                        return bus_send_error_reply(connection, message, NULL, -EINVAL);

                if (!streq_ptr(name, data[PROP_HOSTNAME])) {
                        char *h;

                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-hostname", interactive, &error);
                        if (r < 0)
                                return bus_send_error_reply(connection, message, &error, r);

                        h = strdup(name);
                        if (!h)
                                goto oom;

                        free(data[PROP_HOSTNAME]);
                        data[PROP_HOSTNAME] = h;

                        r = write_data_hostname();
                        if (r < 0)
                                return bus_send_error_reply(connection, message, NULL, r);

                        log_info("Changed host name to '%s'", data[PROP_HOSTNAME]);

                        changed = bus_properties_changed_new(
                                        "/org/freedesktop/hostname1",
                                        "org.freedesktop.hostname1",
                                        "Hostname\0");
                        if (!changed)
                                goto oom;
                }

        } else if (dbus_message_is_method_call(message, "org.freedesktop.hostname1", "SetStaticHostname")) {
                const char *name;
                dbus_bool_t interactive;

                if (!dbus_message_get_args(
                                    message,
                                    &error,
                                    DBUS_TYPE_STRING, &name,
                                    DBUS_TYPE_BOOLEAN, &interactive,
                                    DBUS_TYPE_INVALID))
                        return bus_send_error_reply(connection, message, &error, -EINVAL);

                if (isempty(name))
                        name = NULL;

                if (!streq_ptr(name, data[PROP_STATIC_HOSTNAME])) {

                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-static-hostname", interactive, &error);
                        if (r < 0)
                                return bus_send_error_reply(connection, message, &error, r);

                        if (isempty(name)) {
                                free(data[PROP_STATIC_HOSTNAME]);
                                data[PROP_STATIC_HOSTNAME] = NULL;
                        } else {
                                char *h;

                                if (!hostname_is_valid(name))
                                        return bus_send_error_reply(connection, message, NULL, -EINVAL);

                                h = strdup(name);
                                if (!h)
                                        goto oom;

                                free(data[PROP_STATIC_HOSTNAME]);
                                data[PROP_STATIC_HOSTNAME] = h;
                        }

                        r = write_data_static_hostname();
                        if (r < 0)
                                return bus_send_error_reply(connection, message, NULL, r);

                        log_info("Changed static host name to '%s'", data[PROP_HOSTNAME]);

                        changed = bus_properties_changed_new(
                                        "/org/freedesktop/hostname1",
                                        "org.freedesktop.hostname1",
                                        "StaticHostname\0");
                        if (!changed)
                                goto oom;
                }

        } else if (dbus_message_is_method_call(message, "org.freedesktop.hostname1", "SetPrettyHostname") ||
                   dbus_message_is_method_call(message, "org.freedesktop.hostname1", "SetIconName")) {

                const char *name;
                dbus_bool_t interactive;
                int k;

                if (!dbus_message_get_args(
                                    message,
                                    &error,
                                    DBUS_TYPE_STRING, &name,
                                    DBUS_TYPE_BOOLEAN, &interactive,
                                    DBUS_TYPE_INVALID))
                        return bus_send_error_reply(connection, message, &error, -EINVAL);

                if (isempty(name))
                        name = NULL;

                k = streq(dbus_message_get_member(message), "SetPrettyHostname") ? PROP_PRETTY_HOSTNAME : PROP_ICON_NAME;

                if (!streq_ptr(name, data[k])) {

                        r = verify_polkit(connection, message, "org.freedesktop.hostname1.set-machine-info", interactive, &error);
                        if (r < 0)
                                return bus_send_error_reply(connection, message, &error, r);

                        if (isempty(name)) {
                                free(data[k]);
                                data[k] = NULL;
                        } else {
                                char *h;

                                h = strdup(name);
                                if (!h)
                                        goto oom;

                                free(data[k]);
                                data[k] = h;
                        }

                        r = write_data_other();
                        if (r < 0)
                                return bus_send_error_reply(connection, message, NULL, r);

                        log_info("Changed %s to '%s'", k == PROP_PRETTY_HOSTNAME ? "pretty host name" : "icon name", data[k]);

                        changed = bus_properties_changed_new(
                                        "/org/freedesktop/hostname1",
                                        "org.freedesktop.hostname1",
                                        k == PROP_PRETTY_HOSTNAME ? "PrettyHostname\0" : "IconName\0");
                        if (!changed)
                                goto oom;
                }

        } else
                return bus_default_message_handler(connection, message, INTROSPECTION, INTERFACES_LIST, properties);

        if (!(reply = dbus_message_new_method_return(message)))
                goto oom;

        if (!dbus_connection_send(connection, reply, NULL))
                goto oom;

        dbus_message_unref(reply);
        reply = NULL;

        if (changed) {

                if (!dbus_connection_send(connection, changed, NULL))
                        goto oom;

                dbus_message_unref(changed);
        }

        return DBUS_HANDLER_RESULT_HANDLED;

oom:
        if (reply)
                dbus_message_unref(reply);

        if (changed)
                dbus_message_unref(changed);

        dbus_error_free(&error);

        return DBUS_HANDLER_RESULT_NEED_MEMORY;
}

int main(int argc, char *argv[]) {
        const DBusObjectPathVTable hostname_vtable = {
                .message_function = hostname_message_handler
        };

        DBusConnection *bus = NULL;
        DBusError error;
        int r;

        dbus_error_init(&error);

        log_set_target(LOG_TARGET_AUTO);
        log_parse_environment();
        log_open();

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

        umask(0022);

        r = read_data();
        if (r < 0) {
                log_error("Failed to read hostname data: %s", strerror(-r));
                goto finish;
        }

        bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
        if (!bus) {
                log_error("Failed to get system D-Bus connection: %s", error.message);
                r = -ECONNREFUSED;
                goto finish;
        }

        if (!dbus_connection_register_object_path(bus, "/org/freedesktop/hostname1", &hostname_vtable, NULL)) {
                log_error("Not enough memory");
                r = -ENOMEM;
                goto finish;
        }

        if (dbus_bus_request_name(bus, "org.freedesktop.hostname1", DBUS_NAME_FLAG_DO_NOT_QUEUE, &error) < 0) {
                log_error("Failed to register name on bus: %s", error.message);
                goto finish;
        }

        while (dbus_connection_read_write_dispatch(bus, -1))
                ;

        r = 0;

finish:
        free_data();

        if (bus) {
                dbus_connection_flush(bus);
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
        }

        dbus_error_free(&error);

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}