./move.sh

3 files changed, 752 insertions, 0 deletions

diff --git a/src/systemd-activate/Makefile b/src/systemd-activate/Makefile
new file mode 100644
index 0000000000..8659cb1beb
--- /dev/null
+++ b/src/systemd-activate/Makefile
@@ -0,0 +1,37 @@
+#  -*- Mode: makefile; indent-tabs-mode: t -*-
+#
+#  This file is part of systemd.
+#
+#  Copyright 2010-2012 Lennart Poettering
+#  Copyright 2010-2012 Kay Sievers
+#  Copyright 2013 Zbigniew Jędrzejewski-Szmek
+#  Copyright 2013 David Strauss
+#  Copyright 2016 Luke Shumaker
+#
+#  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 $(dir $(lastword $(MAKEFILE_LIST)))/../../config.mk
+include $(topsrcdir)/build-aux/Makefile.head.mk
+
+
+libexec_PROGRAMS += \
+	systemd-activate
+
+systemd_activate_SOURCES = \
+	src/activate/activate.c
+
+systemd_activate_LDADD = \
+	libshared.la
+
+$(eval $(value automake2autothing))
+include $(topsrcdir)/build-aux/Makefile.tail.mk
diff --git a/src/systemd-activate/activate.c b/src/systemd-activate/activate.c
new file mode 100644
index 0000000000..94f99028e5
--- /dev/null
+++ b/src/systemd-activate/activate.c
@@ -0,0 +1,511 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Zbigniew Jędrzejewski-Szmek
+
+  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 <getopt.h>
+#include <sys/epoll.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <systemd/sd-daemon.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "log.h"
+#include "macro.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+static char** arg_listen = NULL;
+static bool arg_accept = false;
+static int arg_socket_type = SOCK_STREAM;
+static char** arg_args = NULL;
+static char** arg_setenv = NULL;
+static const char *arg_fdname = NULL;
+static bool arg_inetd = false;
+
+static int add_epoll(int epoll_fd, int fd) {
+        struct epoll_event ev = {
+                .events = EPOLLIN
+        };
+        int r;
+
+        assert(epoll_fd >= 0);
+        assert(fd >= 0);
+
+        ev.data.fd = fd;
+        r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev);
+        if (r < 0)
+                return log_error_errno(errno, "Failed to add event on epoll fd:%d for fd:%d: %m", epoll_fd, fd);
+
+        return 0;
+}
+
+static int open_sockets(int *epoll_fd, bool accept) {
+        char **address;
+        int n, fd, r;
+        int count = 0;
+
+        n = sd_listen_fds(true);
+        if (n < 0)
+                return log_error_errno(n, "Failed to read listening file descriptors from environment: %m");
+        if (n > 0) {
+                log_info("Received %i descriptors via the environment.", n);
+
+                for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
+                        r = fd_cloexec(fd, arg_accept);
+                        if (r < 0)
+                                return r;
+
+                        count ++;
+                }
+        }
+
+        /* Close logging and all other descriptors */
+        if (arg_listen) {
+                int except[3 + n];
+
+                for (fd = 0; fd < SD_LISTEN_FDS_START + n; fd++)
+                        except[fd] = fd;
+
+                log_close();
+                close_all_fds(except, 3 + n);
+        }
+
+        /** Note: we leak some fd's on error here. I doesn't matter
+         *  much, since the program will exit immediately anyway, but
+         *  would be a pain to fix.
+         */
+
+        STRV_FOREACH(address, arg_listen) {
+                fd = make_socket_fd(LOG_DEBUG, *address, arg_socket_type, (arg_accept*SOCK_CLOEXEC));
+                if (fd < 0) {
+                        log_open();
+                        return log_error_errno(fd, "Failed to open '%s': %m", *address);
+                }
+
+                assert(fd == SD_LISTEN_FDS_START + count);
+                count ++;
+        }
+
+        if (arg_listen)
+                log_open();
+
+        *epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+        if (*epoll_fd < 0)
+                return log_error_errno(errno, "Failed to create epoll object: %m");
+
+        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + count; fd++) {
+                _cleanup_free_ char *name = NULL;
+
+                getsockname_pretty(fd, &name);
+                log_info("Listening on %s as %i.", strna(name), fd);
+
+                r = add_epoll(*epoll_fd, fd);
+                if (r < 0)
+                        return r;
+        }
+
+        return count;
+}
+
+static int exec_process(const char* name, char **argv, char **env, int start_fd, int n_fds) {
+
+        _cleanup_strv_free_ char **envp = NULL;
+        _cleanup_free_ char *joined = NULL;
+        unsigned n_env = 0, length;
+        const char *tocopy;
+        unsigned i;
+        char **s;
+        int r;
+
+        if (arg_inetd && n_fds != 1) {
+                log_error("--inetd only supported for single file descriptors.");
+                return -EINVAL;
+        }
+
+        length = strv_length(arg_setenv);
+
+        /* PATH, TERM, HOME, USER, LISTEN_FDS, LISTEN_PID, LISTEN_FDNAMES, NULL */
+        envp = new0(char *, length + 8);
+        if (!envp)
+                return log_oom();
+
+        STRV_FOREACH(s, arg_setenv) {
+
+                if (strchr(*s, '=')) {
+                        char *k;
+
+                        k = strdup(*s);
+                        if (!k)
+                                return log_oom();
+
+                        envp[n_env++] = k;
+                } else {
+                        _cleanup_free_ char *p;
+                        const char *n;
+
+                        p = strappend(*s, "=");
+                        if (!p)
+                                return log_oom();
+
+                        n = strv_find_prefix(env, p);
+                        if (!n)
+                                continue;
+
+                        envp[n_env] = strdup(n);
+                        if (!envp[n_env])
+                                return log_oom();
+
+                        n_env ++;
+                }
+        }
+
+        FOREACH_STRING(tocopy, "TERM=", "PATH=", "USER=", "HOME=") {
+                const char *n;
+
+                n = strv_find_prefix(env, tocopy);
+                if (!n)
+                        continue;
+
+                envp[n_env] = strdup(n);
+                if (!envp[n_env])
+                        return log_oom();
+
+                n_env ++;
+        }
+
+        if (arg_inetd) {
+                assert(n_fds == 1);
+
+                r = dup2(start_fd, STDIN_FILENO);
+                if (r < 0)
+                        return log_error_errno(errno, "Failed to dup connection to stdin: %m");
+
+                r = dup2(start_fd, STDOUT_FILENO);
+                if (r < 0)
+                        return log_error_errno(errno, "Failed to dup connection to stdout: %m");
+
+                start_fd = safe_close(start_fd);
+        } else {
+                if (start_fd != SD_LISTEN_FDS_START) {
+                        assert(n_fds == 1);
+
+                        r = dup2(start_fd, SD_LISTEN_FDS_START);
+                        if (r < 0)
+                                return log_error_errno(errno, "Failed to dup connection: %m");
+
+                        safe_close(start_fd);
+                        start_fd = SD_LISTEN_FDS_START;
+                }
+
+                if (asprintf((char**)(envp + n_env++), "LISTEN_FDS=%i", n_fds) < 0)
+                        return log_oom();
+
+                if (asprintf((char**)(envp + n_env++), "LISTEN_PID=" PID_FMT, getpid()) < 0)
+                        return log_oom();
+
+                if (arg_fdname) {
+                        char *e;
+
+                        e = strappend("LISTEN_FDNAMES=", arg_fdname);
+                        if (!e)
+                                return log_oom();
+
+                        for (i = 1; i < (unsigned) n_fds; i++) {
+                                char *c;
+
+                                c = strjoin(e, ":", arg_fdname, NULL);
+                                if (!c) {
+                                        free(e);
+                                        return log_oom();
+                                }
+
+                                free(e);
+                                e = c;
+                        }
+
+                        envp[n_env++] = e;
+                }
+        }
+
+        joined = strv_join(argv, " ");
+        if (!joined)
+                return log_oom();
+
+        log_info("Execing %s (%s)", name, joined);
+        execvpe(name, argv, envp);
+
+        return log_error_errno(errno, "Failed to execp %s (%s): %m", name, joined);
+}
+
+static int fork_and_exec_process(const char* child, char** argv, char **env, int fd) {
+        _cleanup_free_ char *joined = NULL;
+        pid_t parent_pid, child_pid;
+
+        joined = strv_join(argv, " ");
+        if (!joined)
+                return log_oom();
+
+        parent_pid = getpid();
+
+        child_pid = fork();
+        if (child_pid < 0)
+                return log_error_errno(errno, "Failed to fork: %m");
+
+        /* In the child */
+        if (child_pid == 0) {
+
+                (void) reset_all_signal_handlers();
+                (void) reset_signal_mask();
+
+                /* Make sure the child goes away when the parent dies */
+                if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
+                        _exit(EXIT_FAILURE);
+
+                /* Check whether our parent died before we were able
+                 * to set the death signal */
+                if (getppid() != parent_pid)
+                        _exit(EXIT_SUCCESS);
+
+                exec_process(child, argv, env, fd, 1);
+                _exit(EXIT_FAILURE);
+        }
+
+        log_info("Spawned %s (%s) as PID %d", child, joined, child_pid);
+        return 0;
+}
+
+static int do_accept(const char* name, char **argv, char **envp, int fd) {
+        _cleanup_free_ char *local = NULL, *peer = NULL;
+        _cleanup_close_ int fd_accepted = -1;
+
+        fd_accepted = accept4(fd, NULL, NULL, 0);
+        if (fd_accepted < 0)
+                return log_error_errno(errno, "Failed to accept connection on fd:%d: %m", fd);
+
+        getsockname_pretty(fd_accepted, &local);
+        getpeername_pretty(fd_accepted, true, &peer);
+        log_info("Connection from %s to %s", strna(peer), strna(local));
+
+        return fork_and_exec_process(name, argv, envp, fd_accepted);
+}
+
+/* SIGCHLD handler. */
+static void sigchld_hdl(int sig, siginfo_t *t, void *data) {
+        PROTECT_ERRNO;
+
+        log_info("Child %d died with code %d", t->si_pid, t->si_status);
+
+        /* Wait for a dead child. */
+        (void) waitpid(t->si_pid, NULL, 0);
+}
+
+static int install_chld_handler(void) {
+        static const struct sigaction act = {
+                .sa_flags = SA_SIGINFO,
+                .sa_sigaction = sigchld_hdl,
+        };
+
+        int r;
+
+        r = sigaction(SIGCHLD, &act, 0);
+        if (r < 0)
+                return log_error_errno(errno, "Failed to install SIGCHLD handler: %m");
+
+        return 0;
+}
+
+static void help(void) {
+        printf("%s [OPTIONS...]\n\n"
+               "Listen on sockets and launch child on connection.\n\n"
+               "Options:\n"
+               "  -h --help                Show this help and exit\n"
+               "     --version             Print version string and exit\n"
+               "  -l --listen=ADDR         Listen for raw connections at ADDR\n"
+               "  -d --datagram            Listen on datagram instead of stream socket\n"
+               "     --seqpacket           Listen on SOCK_SEQPACKET instead of stream socket\n"
+               "  -a --accept              Spawn separate child for each connection\n"
+               "  -E --setenv=NAME[=VALUE] Pass an environment variable to children\n"
+               "     --inetd               Enable inetd file descriptor passing protocol\n"
+               "\n"
+               "Note: file descriptors from sd_listen_fds() will be passed through.\n"
+               , program_invocation_short_name);
+}
+
+static int parse_argv(int argc, char *argv[]) {
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_FDNAME,
+                ARG_SEQPACKET,
+                ARG_INETD,
+        };
+
+        static const struct option options[] = {
+                { "help",        no_argument,       NULL, 'h'           },
+                { "version",     no_argument,       NULL, ARG_VERSION   },
+                { "datagram",    no_argument,       NULL, 'd'           },
+                { "seqpacket",   no_argument,       NULL, ARG_SEQPACKET },
+                { "listen",      required_argument, NULL, 'l'           },
+                { "accept",      no_argument,       NULL, 'a'           },
+                { "setenv",      required_argument, NULL, 'E'           },
+                { "environment", required_argument, NULL, 'E'           }, /* legacy alias */
+                { "fdname",      required_argument, NULL, ARG_FDNAME    },
+                { "inetd",       no_argument,       NULL, ARG_INETD     },
+                {}
+        };
+
+        int c, r;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "+hl:aEd", options, NULL)) >= 0)
+                switch(c) {
+                case 'h':
+                        help();
+                        return 0;
+
+                case ARG_VERSION:
+                        return version();
+
+                case 'l':
+                        r = strv_extend(&arg_listen, optarg);
+                        if (r < 0)
+                                return log_oom();
+
+                        break;
+
+                case 'd':
+                        if (arg_socket_type == SOCK_SEQPACKET) {
+                                log_error("--datagram may not be combined with --seqpacket.");
+                                return -EINVAL;
+                        }
+
+                        arg_socket_type = SOCK_DGRAM;
+                        break;
+
+                case ARG_SEQPACKET:
+                        if (arg_socket_type == SOCK_DGRAM) {
+                                log_error("--seqpacket may not be combined with --datagram.");
+                                return -EINVAL;
+                        }
+
+                        arg_socket_type = SOCK_SEQPACKET;
+                        break;
+
+                case 'a':
+                        arg_accept = true;
+                        break;
+
+                case 'E':
+                        r = strv_extend(&arg_setenv, optarg);
+                        if (r < 0)
+                                return log_oom();
+
+                        break;
+
+                case ARG_FDNAME:
+                        if (!fdname_is_valid(optarg)) {
+                                log_error("File descriptor name %s is not valid, refusing.", optarg);
+                                return -EINVAL;
+                        }
+
+                        arg_fdname = optarg;
+                        break;
+
+                case ARG_INETD:
+                        arg_inetd = true;
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        if (optind == argc) {
+                log_error("%s: command to execute is missing.",
+                          program_invocation_short_name);
+                return -EINVAL;
+        }
+
+        if (arg_socket_type == SOCK_DGRAM && arg_accept) {
+                log_error("Datagram sockets do not accept connections. "
+                          "The --datagram and --accept options may not be combined.");
+                return -EINVAL;
+        }
+
+        arg_args = argv + optind;
+
+        return 1 /* work to do */;
+}
+
+int main(int argc, char **argv, char **envp) {
+        int r, n;
+        int epoll_fd = -1;
+
+        log_parse_environment();
+        log_open();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+
+        r = install_chld_handler();
+        if (r < 0)
+                return EXIT_FAILURE;
+
+        n = open_sockets(&epoll_fd, arg_accept);
+        if (n < 0)
+                return EXIT_FAILURE;
+        if (n == 0) {
+                log_error("No sockets to listen on specified or passed in.");
+                return EXIT_FAILURE;
+        }
+
+        for (;;) {
+                struct epoll_event event;
+
+                r = epoll_wait(epoll_fd, &event, 1, -1);
+                if (r < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        log_error_errno(errno, "epoll_wait() failed: %m");
+                        return EXIT_FAILURE;
+                }
+
+                log_info("Communication attempt on fd %i.", event.data.fd);
+                if (arg_accept) {
+                        r = do_accept(argv[optind], argv + optind, envp, event.data.fd);
+                        if (r < 0)
+                                return EXIT_FAILURE;
+                } else
+                        break;
+        }
+
+        exec_process(argv[optind], argv + optind, envp, SD_LISTEN_FDS_START, n);
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/systemd-activate/systemd-activate.xml b/src/systemd-activate/systemd-activate.xml
new file mode 100644
index 0000000000..995e6eecce
--- /dev/null
+++ b/src/systemd-activate/systemd-activate.xml
@@ -0,0 +1,204 @@
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+  This file is part of systemd.
+
+  Copyright 2013 Zbigniew Jędrzejewski-Szmek
+
+  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/>.
+-->
+
+<refentry id="systemd-activate"
+          xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>systemd-activate</title>
+    <productname>systemd</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Zbigniew</firstname>
+        <surname>Jędrzejewski-Szmek</surname>
+        <email>zbyszek@in.waw.pl</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>systemd-activate</refentrytitle>
+    <manvolnum>8</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>systemd-activate</refname>
+    <refpurpose>Test socket activation of daemons</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <cmdsynopsis>
+      <command>/usr/lib/systemd/systemd-activate</command>
+      <arg choice="opt" rep="repeat">OPTIONS</arg>
+      <arg choice="plain"><replaceable>daemon</replaceable></arg>
+      <arg choice="opt" rep="repeat">OPTIONS</arg>
+    </cmdsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><command>systemd-activate</command> may be used to launch a socket-activated service binary from the command
+    line for testing purposes. It may also be used to launch individual instances of the service binary per connection.
+    </para>
+
+    <para>The daemon to launch and its options should be specified
+    after options intended for <command>systemd-activate</command>.
+    </para>
+
+    <para>If the <option>--inetd</option> option is given, the socket file descriptor will be used as the standard
+    input and output of the launched process. Otherwise, standard input and output will be inherited, and sockets will
+    be passed through file descriptors 3 and higher. Sockets passed through <varname>$LISTEN_FDS</varname> to
+    <command>systemd-activate</command> will be passed through to the daemon, in the original positions. Other sockets
+    specified with <option>--listen=</option> will use consecutive descriptors.  By default,
+    <command>systemd-activate</command> listens on a stream socket, use <option>--datagram</option> and
+    <option>--seqpacket</option> to listen on datagram or sequential packet sockets instead (see below).
+    </para>
+  </refsect1>
+
+  <refsect1>
+    <title>Options</title>
+    <variablelist>
+      <varlistentry>
+        <term><option>-l <replaceable>address</replaceable></option></term>
+        <term><option>--listen=<replaceable>address</replaceable></option></term>
+
+        <listitem><para>Listen on this <replaceable>address</replaceable>.
+        Takes a string like <literal>2000</literal> or
+        <literal>127.0.0.1:2001</literal>.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>-a</option></term>
+        <term><option>--accept</option></term>
+
+        <listitem><para>Launch an instance of the service binary for each connection and pass the connection
+        socket.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>-d</option></term>
+        <term><option>--datagram</option></term>
+
+        <listitem><para>Listen on a datagram socket (<constant>SOCK_DGRAM</constant>), instead of a stream socket
+        (<constant>SOCK_STREAM</constant>). May not be combined with <option>--seqpacket</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--seqpacket</option></term>
+
+        <listitem><para>Listen on a sequential packet socket (<constant>SOCK_SEQPACKET</constant>), instead of a stream
+        socket (<constant>SOCK_STREAM</constant>). May not be combined with
+        <option>--datagram</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--inetd</option></term>
+
+        <listitem><para>Use the inetd protocol for passing file descriptors, i.e. as standard input and standard
+        output, instead of the new-style protocol for passing file descriptors using <varname>$LISTEN_FDS</varname>
+        (see above).</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>-E <replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>
+        <term><option>--setenv=<replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>
+
+        <listitem><para>Add this variable to the environment of the
+        launched process. If <replaceable>VAR</replaceable> is
+        followed by <literal>=</literal>, assume that it is a
+        variable–value pair. Otherwise, obtain the value from the
+        environment of <command>systemd-activate</command> itself.
+        </para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--fdname=</option><replaceable>NAME</replaceable></term>
+
+        <listitem><para>Specify a name for the activation file
+        descriptors. This is equivalent to setting
+        <varname>FileDescriptorName=</varname> in socket unit files, and
+        enables use of
+        <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+      </varlistentry>
+
+      <xi:include href="standard-options.xml" xpointer="help" />
+      <xi:include href="standard-options.xml" xpointer="version" />
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Environment variables</title>
+    <variablelist class='environment-variables'>
+      <varlistentry>
+        <term><varname>$LISTEN_FDS</varname></term>
+        <term><varname>$LISTEN_PID</varname></term>
+        <term><varname>$LISTEN_FDNAMES</varname></term>
+
+        <listitem><para>See
+        <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
+        <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
+        <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
+        <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>
+
+        <listitem><para>Same as in
+        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para></listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Examples</title>
+
+    <example>
+      <title>Run an echo server on port 2000</title>
+
+      <programlisting>$ /usr/lib/systemd/systemd-activate -l 2000 --inetd -a cat</programlisting>
+    </example>
+
+    <example>
+      <title>Run a socket-activated instance of <citerefentry><refentrytitle>systemd-journal-gatewayd</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>
+
+      <programlisting>$ /usr/lib/systemd/systemd-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd</programlisting>
+    </example>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry project='man-pages'><refentrytitle>cat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+</refentry>