systemctl: support remote and privileged systemctl access via SSH and pkexec

This adds support for executing systemctl operations remotely or as
privileged user while still running systemctl itself unprivileged and
locally.

This currently requires a D-Bus patch to work properly.

https://bugs.freedesktop.org/show_bug.cgi?id=35230

5 files changed, 556 insertions, 52 deletions

diff --git a/src/bridge.c b/src/bridge.c
new file mode 100644
index 0000000000..5ee058a37f
--- /dev/null
+++ b/src/bridge.c
@@ -0,0 +1,367 @@
+/*-*- 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 <sys/socket.h>
+#include <sys/un.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/epoll.h>
+#include <stddef.h>
+
+#include "log.h"
+#include "util.h"
+#include "socket-util.h"
+
+#define BUFFER_SIZE (64*1024)
+#define EXTRA_SIZE 16
+
+static bool initial_nul = false;
+static bool auth_over = false;
+
+static void format_uid(char *buf, size_t l) {
+        char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
+        unsigned j;
+
+        assert(l > 0);
+
+        snprintf(text, sizeof(text)-1, "%llu", (unsigned long long) geteuid());
+        text[sizeof(text)-1] = 0;
+
+        memset(buf, 0, l);
+
+        for (j = 0; text[j] && j*2+2 < l; j++) {
+                buf[j*2]   = hexchar(text[j] >> 4);
+                buf[j*2+1] = hexchar(text[j] & 0xF);
+        }
+
+        buf[j*2] = 0;
+}
+
+static size_t patch_in_line(char *line, size_t l, size_t left) {
+        size_t r;
+
+        if (line[0] == 0 && !initial_nul) {
+                initial_nul = true;
+                line += 1;
+                l -= 1;
+                r = 1;
+        } else
+                r = 0;
+
+        if (l == 5 && strncmp(line, "BEGIN", 5) == 0) {
+                r += l;
+                auth_over = true;
+
+        } else if (l == 17 && strncmp(line, "NEGOTIATE_UNIX_FD", 17) == 0) {
+                memmove(line + 13, line + 17, left);
+                memcpy(line, "NEGOTIATE_NOP", 13);
+                r += 13;
+
+        } else if (l >= 14 && strncmp(line, "AUTH EXTERNAL ", 14) == 0) {
+                char uid[20*2 + 1];
+                size_t len;
+
+                format_uid(uid, sizeof(uid));
+                len = strlen(uid);
+                assert(len <= EXTRA_SIZE);
+
+                memmove(line + 14 + len, line + l, left);
+                memcpy(line + 14, uid, len);
+
+                r += 14 + len;
+        } else
+                r += l;
+
+        return r;
+}
+
+static size_t patch_in_buffer(char* in_buffer, size_t *in_buffer_full) {
+        size_t i, good = 0;
+
+        if (*in_buffer_full <= 0)
+                return *in_buffer_full;
+
+        /* If authentication is done, we don't touch anything anymore */
+        if (auth_over)
+                return *in_buffer_full;
+
+        if (*in_buffer_full < 2)
+                return 0;
+
+        for (i = 0; i <= *in_buffer_full - 2; i ++) {
+
+                /* Fully lines can be send on */
+                if (in_buffer[i] == '\r' && in_buffer[i+1] == '\n') {
+                        if (i > good) {
+                                size_t old_length, new_length;
+
+                                old_length = i - good;
+                                new_length = patch_in_line(in_buffer+good, old_length, *in_buffer_full - i);
+                                *in_buffer_full = *in_buffer_full + new_length - old_length;
+
+                                good += new_length + 2;
+
+                        } else
+                                good = i+2;
+                }
+
+                if (auth_over)
+                        break;
+        }
+
+        return good;
+}
+
+int main(int argc, char *argv[]) {
+        int r = EXIT_FAILURE, fd = -1, ep = -1;
+        union sockaddr_union sa;
+        char in_buffer[BUFFER_SIZE+EXTRA_SIZE], out_buffer[BUFFER_SIZE+EXTRA_SIZE];
+        size_t in_buffer_full = 0, out_buffer_full = 0;
+        struct epoll_event stdin_ev, stdout_ev, fd_ev;
+        bool stdin_readable = false, stdout_writable = false, fd_readable = false, fd_writable = false;
+        bool stdin_rhup = false, stdout_whup = false, fd_rhup = false, fd_whup = false;
+
+        if (argc > 1) {
+                log_error("This program takes no argument.");
+                return EXIT_FAILURE;
+        }
+
+        log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
+        log_parse_environment();
+        log_open();
+
+        if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0)) < 0) {
+                log_error("Failed to create socket: %s", strerror(errno));
+                goto finish;
+        }
+
+        zero(sa);
+        sa.un.sun_family = AF_UNIX;
+        strncpy(sa.un.sun_path, "/var/run/dbus/system_bus_socket", sizeof(sa.un.sun_path));
+
+        if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + 1 + strlen(sa.un.sun_path+1)) < 0) {
+                log_error("Failed to connect: %m");
+                goto finish;
+        }
+
+        fd_nonblock(STDIN_FILENO, 1);
+        fd_nonblock(STDOUT_FILENO, 1);
+
+        if ((ep = epoll_create1(EPOLL_CLOEXEC)) < 0) {
+                log_error("Failed to create epoll: %m");
+                goto finish;
+        }
+
+        zero(stdin_ev);
+        stdin_ev.events = EPOLLIN|EPOLLET;
+        stdin_ev.data.fd = STDIN_FILENO;
+
+        zero(stdout_ev);
+        stdout_ev.events = EPOLLOUT|EPOLLET;
+        stdout_ev.data.fd = STDOUT_FILENO;
+
+        zero(fd_ev);
+        fd_ev.events = EPOLLIN|EPOLLOUT|EPOLLET;
+        fd_ev.data.fd = fd;
+
+        if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0 ||
+            epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 ||
+            epoll_ctl(ep, EPOLL_CTL_ADD, fd, &fd_ev) < 0) {
+                log_error("Failed to regiser fds in epoll: %m");
+                goto finish;
+        }
+
+        do {
+                struct epoll_event ev[16];
+                ssize_t k;
+                int i, nfds;
+
+                if ((nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), -1)) < 0) {
+
+                        if (errno == EINTR || errno == EAGAIN)
+                                continue;
+
+                        log_error("epoll_wait(): %m");
+                        goto finish;
+                }
+
+                assert(nfds >= 1);
+
+                for (i = 0; i < nfds; i++) {
+                        if (ev[i].data.fd == STDIN_FILENO) {
+
+                                if (!stdin_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN)))
+                                        stdin_readable = true;
+
+                        } else if (ev[i].data.fd == STDOUT_FILENO) {
+
+                                if (ev[i].events & EPOLLHUP) {
+                                        stdout_writable = false;
+                                        stdout_whup = true;
+                                }
+
+                                if (!stdout_whup && (ev[i].events & EPOLLOUT))
+                                        stdout_writable = true;
+
+                        } else if (ev[i].data.fd == fd) {
+
+                                if (ev[i].events & EPOLLHUP) {
+                                        fd_writable = false;
+                                        fd_whup = true;
+                                }
+
+                                if (!fd_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN)))
+                                        fd_readable = true;
+
+                                if (!fd_whup && (ev[i].events & EPOLLOUT))
+                                        fd_writable = true;
+                        }
+                }
+
+                while ((stdin_readable && in_buffer_full <= 0) ||
+                       (fd_writable && patch_in_buffer(in_buffer, &in_buffer_full) > 0) ||
+                       (fd_readable && out_buffer_full <= 0) ||
+                       (stdout_writable && out_buffer_full > 0)) {
+
+                        size_t in_buffer_good = 0;
+
+                        if (stdin_readable && in_buffer_full < BUFFER_SIZE) {
+
+                                if ((k = read(STDIN_FILENO, in_buffer + in_buffer_full, BUFFER_SIZE - in_buffer_full)) < 0) {
+
+                                        if (errno == EAGAIN)
+                                                stdin_readable = false;
+                                        else if (errno == EPIPE || errno == ECONNRESET)
+                                                k = 0;
+                                        else {
+                                                log_error("read(): %m");
+                                                goto finish;
+                                        }
+                                } else
+                                        in_buffer_full += (size_t) k;
+
+                                if (k == 0) {
+                                        stdin_rhup = true;
+                                        stdin_readable = false;
+                                        shutdown(STDIN_FILENO, SHUT_RD);
+                                        close_nointr_nofail(STDIN_FILENO);
+                                }
+                        }
+
+                        in_buffer_good = patch_in_buffer(in_buffer, &in_buffer_full);
+
+                        if (fd_writable && in_buffer_good > 0) {
+
+                                if ((k = write(fd, in_buffer, in_buffer_good)) < 0) {
+
+                                        if (errno == EAGAIN)
+                                                fd_writable = false;
+                                        else if (errno == EPIPE || errno == ECONNRESET) {
+                                                fd_whup = true;
+                                                fd_writable = false;
+                                                shutdown(fd, SHUT_WR);
+                                        } else {
+                                                log_error("write(): %m");
+                                                goto finish;
+                                        }
+
+                                } else {
+                                        assert(in_buffer_full >= (size_t) k);
+                                        memmove(in_buffer, in_buffer + k, in_buffer_full - k);
+                                        in_buffer_full -= k;
+                                }
+                        }
+
+                        if (fd_readable && out_buffer_full < BUFFER_SIZE) {
+
+                                if ((k = read(fd, out_buffer + out_buffer_full, BUFFER_SIZE - out_buffer_full)) < 0) {
+
+                                        if (errno == EAGAIN)
+                                                fd_readable = false;
+                                        else if (errno == EPIPE || errno == ECONNRESET)
+                                                k = 0;
+                                        else {
+                                                log_error("read(): %m");
+                                                goto finish;
+                                        }
+                                }  else
+                                        out_buffer_full += (size_t) k;
+
+                                if (k == 0) {
+                                        fd_rhup = true;
+                                        fd_readable = false;
+                                        shutdown(fd, SHUT_RD);
+                                }
+                        }
+
+                        if (stdout_writable && out_buffer_full > 0) {
+
+                                if ((k = write(STDOUT_FILENO, out_buffer, out_buffer_full)) < 0) {
+
+                                        if (errno == EAGAIN)
+                                                stdout_writable = false;
+                                        else if (errno == EPIPE || errno == ECONNRESET) {
+                                                stdout_whup = true;
+                                                stdout_writable = false;
+                                                shutdown(STDOUT_FILENO, SHUT_WR);
+                                                close_nointr(STDOUT_FILENO);
+                                        } else {
+                                                log_error("write(): %m");
+                                                goto finish;
+                                        }
+
+                                } else {
+                                        assert(out_buffer_full >= (size_t) k);
+                                        memmove(out_buffer, out_buffer + k, out_buffer_full - k);
+                                        out_buffer_full -= k;
+                                }
+                        }
+                }
+
+                if (stdin_rhup && in_buffer_full <= 0 && !fd_whup) {
+                        fd_whup = true;
+                        fd_writable = false;
+                        shutdown(fd, SHUT_WR);
+                }
+
+                if (fd_rhup && out_buffer_full <= 0 && !stdout_whup) {
+                        stdout_whup = true;
+                        stdout_writable = false;
+                        shutdown(STDOUT_FILENO, SHUT_WR);
+                        close_nointr(STDOUT_FILENO);
+                }
+
+        } while (!stdout_whup || !fd_whup);
+
+        r = EXIT_SUCCESS;
+
+finish:
+        if (fd >= 0)
+                close_nointr_nofail(fd);
+
+        if (ep >= 0)
+                close_nointr_nofail(ep);
+
+        return r;
+}
diff --git a/src/dbus-common.c b/src/dbus-common.c
index 809ea0f67a..25b718ec02 100644
--- a/src/dbus-common.c
+++ b/src/dbus-common.c
@@ -23,6 +23,8 @@
 #include <sys/socket.h>
 #include <errno.h>
 #include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <dbus/dbus.h>
 
 #include "log.h"
@@ -55,59 +57,63 @@ int bus_check_peercred(DBusConnection *c) {
         return 1;
 }
 
-int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
-        DBusConnection *bus;
+#define TIMEOUT_USEC (60*USEC_PER_SEC)
 
-        assert(_bus);
+static int sync_auth(DBusConnection *bus, DBusError *error) {
+        usec_t begin, tstamp;
 
-#define TIMEOUT_USEC (60*USEC_PER_SEC)
+        assert(bus);
 
-        /* If we are root, then let's not go via the bus */
-        if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
-                usec_t begin, tstamp;
+        /* This complexity should probably move into D-Bus itself:
+         *
+         * https://bugs.freedesktop.org/show_bug.cgi?id=35189 */
 
-                if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
-                        return -EIO;
+        begin = tstamp = now(CLOCK_MONOTONIC);
+        for (;;) {
 
-                if (bus_check_peercred(bus) < 0) {
-                        dbus_connection_close(bus);
-                        dbus_connection_unref(bus);
+                if (tstamp > begin + TIMEOUT_USEC)
+                        break;
 
-                        dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
-                        return -EACCES;
-                }
+                if (dbus_connection_get_is_authenticated(bus))
+                        break;
 
-                /* This complexity should probably move into D-Bus itself:
-                 *
-                 * https://bugs.freedesktop.org/show_bug.cgi?id=35189 */
-                begin = tstamp = now(CLOCK_MONOTONIC);
-                for (;;) {
+                if (!dbus_connection_read_write_dispatch(bus, ((begin + TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
+                        break;
 
-                        if (tstamp > begin + TIMEOUT_USEC)
-                                break;
+                tstamp = now(CLOCK_MONOTONIC);
+        }
 
-                        if (dbus_connection_get_is_authenticated(bus))
-                                break;
+        if (!dbus_connection_get_is_connected(bus)) {
+                dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
+                return -ECONNREFUSED;
+        }
 
-                        if (!dbus_connection_read_write_dispatch(bus, ((begin + TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
-                                break;
+        if (!dbus_connection_get_is_authenticated(bus)) {
+                dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
+                return -EACCES;
+        }
 
-                        tstamp = now(CLOCK_MONOTONIC);
-                }
+        return 0;
+}
 
-                if (!dbus_connection_get_is_connected(bus)) {
-                        dbus_connection_close(bus);
-                        dbus_connection_unref(bus);
+int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
+        DBusConnection *bus;
+        int r;
 
-                        dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
-                        return -ECONNREFUSED;
-                }
+        assert(_bus);
 
-                if (!dbus_connection_get_is_authenticated(bus)) {
+        /* If we are root, then let's not go via the bus */
+        if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
+                if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
+                        return -EIO;
+
+                dbus_connection_set_exit_on_disconnect(bus, FALSE);
+
+                if (bus_check_peercred(bus) < 0) {
                         dbus_connection_close(bus);
                         dbus_connection_unref(bus);
 
-                        dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
+                        dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
                         return -EACCES;
                 }
 
@@ -118,12 +124,93 @@ int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *
                 if (!(bus = dbus_bus_get_private(t, error)))
                         return -EIO;
 
+                dbus_connection_set_exit_on_disconnect(bus, FALSE);
+
                 if (private)
                         *private = false;
         }
 
+        if ((r = sync_auth(bus, error)) < 0) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+                return r;
+        }
+
+        *_bus = bus;
+        return 0;
+}
+
+int bus_connect_system_ssh(const char *user, const char *host, DBusConnection **_bus, DBusError *error) {
+        DBusConnection *bus;
+        char *p = NULL;
+        int r;
+
+        assert(_bus);
+        assert(user || host);
+
+        if (user && host)
+                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@%s,argv3=systemd-stdio-bridge", user, host);
+        else if (user)
+                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@localhost,argv3=systemd-stdio-bridge", user);
+        else if (host)
+                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s,argv3=systemd-stdio-bridge", host);
+
+        if (!p) {
+                dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
+                return -ENOMEM;
+        }
+
+        bus = dbus_connection_open_private(p, error);
+        free(p);
+
+        if (!bus)
+                return -EIO;
+
+        dbus_connection_set_exit_on_disconnect(bus, FALSE);
+
+        if ((r = sync_auth(bus, error)) < 0) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+                return r;
+        }
+
+        if (!dbus_bus_register(bus, error)) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+                return r;
+        }
+
+        *_bus = bus;
+        return 0;
+}
+
+int bus_connect_system_polkit(DBusConnection **_bus, DBusError *error) {
+        DBusConnection *bus;
+        int r;
+
+        assert(_bus);
+
+        /* Don't bother with PolicyKit if we are root */
+        if (geteuid() == 0)
+                return bus_connect(DBUS_BUS_SYSTEM, _bus, NULL, error);
+
+        if (!(bus = dbus_connection_open_private("exec:path=pkexec,argv1=" SYSTEMD_STDIO_BRIDGE_BINARY_PATH, error)))
+                return -EIO;
+
         dbus_connection_set_exit_on_disconnect(bus, FALSE);
 
+        if ((r = sync_auth(bus, error)) < 0) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+                return r;
+        }
+
+        if (!dbus_bus_register(bus, error)) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+                return r;
+        }
+
         *_bus = bus;
         return 0;
 }
diff --git a/src/dbus-common.h b/src/dbus-common.h
index 9a66b78744..76333cd4f6 100644
--- a/src/dbus-common.h
+++ b/src/dbus-common.h
@@ -28,6 +28,9 @@ int bus_check_peercred(DBusConnection *c);
 
 int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private_bus, DBusError *error);
 
+int bus_connect_system_ssh(const char *user, const char *host, DBusConnection **_bus, DBusError *error);
+int bus_connect_system_polkit(DBusConnection **_bus, DBusError *error);
+
 const char *bus_error_message(const DBusError *error);
 
 #endif
diff --git a/src/org.freedesktop.systemd1.policy b/src/org.freedesktop.systemd1.policy
index bb07b827fc..a9958c2e33 100644
--- a/src/org.freedesktop.systemd1.policy
+++ b/src/org.freedesktop.systemd1.policy
@@ -27,4 +27,15 @@
                 <annotate key="org.freedesktop.policykit.exec.path">/lib/systemd/systemd-reply-password</annotate>
         </action>
 
+        <action id="org.freedesktop.systemd1.BusAccess">
+                <description>Privileged system and service manager access</description>
+                <message>Authentication is required to access the system and service manager.</message>
+                <defaults>
+                        <allow_any>no</allow_any>
+                        <allow_inactive>no</allow_inactive>
+                        <allow_active>auth_admin_keep</allow_active>
+                </defaults>
+                <annotate key="org.freedesktop.policykit.exec.path">/usr/bin/systemd-stdio-bridge</annotate>
+        </action>
+
 </policyconfig>
diff --git a/src/systemctl.c b/src/systemctl.c
index 5b205fec56..b8af654e09 100644
--- a/src/systemctl.c
+++ b/src/systemctl.c
@@ -108,6 +108,12 @@ static enum dot {
         DOT_ORDER,
         DOT_REQUIRE
 } arg_dot = DOT_ALL;
+static enum transport {
+        TRANSPORT_NORMAL,
+        TRANSPORT_SSH,
+        TRANSPORT_POLKIT
+} arg_transport = TRANSPORT_NORMAL;
+static const char *arg_host = NULL;
 
 static bool private_bus = false;
 
@@ -2061,12 +2067,14 @@ static void print_status_info(UnitStatusInfo *i) {
 
                 printf("\t  CGroup: %s\n", i->default_control_group);
 
-                if ((c = columns()) > 18)
-                        c -= 18;
-                else
-                        c = 0;
+                if (arg_transport != TRANSPORT_SSH) {
+                        if ((c = columns()) > 18)
+                                c -= 18;
+                        else
+                                c = 0;
 
-                show_cgroup_by_path(i->default_control_group, "\t\t  ", c);
+                        show_cgroup_by_path(i->default_control_group, "\t\t  ", c);
+                }
         }
 
         if (i->need_daemon_reload)
@@ -4290,22 +4298,25 @@ static int systemctl_help(void) {
                "                      pending\n"
                "     --ignore-dependencies\n"
                "                      When queueing a new job, ignore all its dependencies\n"
+               "     --kill-mode=MODE How to send signal\n"
+               "     --kill-who=WHO   Who to send signal to\n"
+               "  -s --signal=SIGNAL  Which signal to send\n"
+               "  -H --host=[user@]host\n"
+               "                      Show information for remote host\n"
+               "  -P --privileged     Acquire privileges before execution\n"
                "  -q --quiet          Suppress output\n"
                "     --no-block       Do not wait until operation finished\n"
-               "     --no-pager       Do not pipe output into a pager.\n"
-               "     --system         Connect to system manager\n"
-               "     --user           Connect to user service manager\n"
-               "     --order          When generating graph for dot, show only order\n"
-               "     --require        When generating graph for dot, show only requirement\n"
                "     --no-wall        Don't send wall message before halt/power-off/reboot\n"
-               "     --global         Enable/disable unit files globally\n"
                "     --no-reload      When enabling/disabling unit files, don't reload daemon\n"
                "                      configuration\n"
+               "     --no-pager       Do not pipe output into a pager.\n"
                "     --no-ask-password\n"
                "                      Do not ask for system passwords\n"
-               "     --kill-mode=MODE How to send signal\n"
-               "     --kill-who=WHO   Who to send signal to\n"
-               "  -s --signal=SIGNAL  Which signal to send\n"
+               "     --order          When generating graph for dot, show only order\n"
+               "     --require        When generating graph for dot, show only requirement\n"
+               "     --system         Connect to system manager\n"
+               "     --user           Connect to user service manager\n"
+               "     --global         Enable/disable unit files globally\n"
                "  -f --force          When enabling unit files, override existing symlinks\n"
                "                      When shutting down, execute action immediately\n"
                "     --defaults       When disabling unit files, remove default symlinks only\n\n"
@@ -4472,6 +4483,8 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                 { "kill-who",  required_argument, NULL, ARG_KILL_WHO  },
                 { "signal",    required_argument, NULL, 's'           },
                 { "no-ask-password", no_argument, NULL, ARG_NO_ASK_PASSWORD },
+                { "host",      required_argument, NULL, 'H'           },
+                { "privileged",no_argument,       NULL, 'P'           },
                 { NULL,        0,                 NULL, 0             }
         };
 
@@ -4483,7 +4496,7 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
         /* Only when running as systemctl we ask for passwords */
         arg_ask_password = true;
 
-        while ((c = getopt_long(argc, argv, "ht:p:aqfs:", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "ht:p:aqfs:H:P", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -4605,6 +4618,15 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                         arg_ask_password = false;
                         break;
 
+                case 'P':
+                        arg_transport = TRANSPORT_POLKIT;
+                        break;
+
+                case 'H':
+                        arg_transport = TRANSPORT_SSH;
+                        arg_host = optarg;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -4614,6 +4636,11 @@ static int systemctl_parse_argv(int argc, char *argv[]) {
                 }
         }
 
+        if (arg_transport != TRANSPORT_NORMAL && arg_user) {
+                log_error("Cannot access user instance remotely.");
+                return -EINVAL;
+        }
+
         return 1;
 }
 
@@ -5622,7 +5649,16 @@ int main(int argc, char*argv[]) {
                 goto finish;
         }
 
-        bus_connect(arg_user ? DBUS_BUS_SESSION : DBUS_BUS_SYSTEM, &bus, &private_bus, &error);
+        if (arg_transport == TRANSPORT_NORMAL)
+                bus_connect(arg_user ? DBUS_BUS_SESSION : DBUS_BUS_SYSTEM, &bus, &private_bus, &error);
+        else if (arg_transport == TRANSPORT_POLKIT) {
+                bus_connect_system_polkit(&bus, &error);
+                private_bus = false;
+        } else if (arg_transport == TRANSPORT_SSH) {
+                bus_connect_system_ssh(NULL, arg_host, &bus, &error);
+                private_bus = false;
+        } else
+                assert_not_reached("Uh, invalid transport...");
 
         switch (arg_action) {