From: Michael Biebl <biebl@debian.org>
Date: Sat, 27 May 2023 01:05:46 +0200
Subject: Stop using embedded copy of sd-daemon.{c,h} and use libsystemd
 instead

Fixes: #287
Fixes: #296
(cherry picked from commit bc116c05b15f1f478a40e47fe9fc68011cef1e50)
---
 avahi-daemon/Makefile.am       |   9 +-
 avahi-daemon/main.c            |  19 +-
 avahi-daemon/sd-daemon.c       | 436 -----------------------------------------
 avahi-daemon/sd-daemon.h       | 265 -------------------------
 avahi-daemon/simple-protocol.c |  12 +-
 configure.ac                   |  21 ++
 6 files changed, 51 insertions(+), 711 deletions(-)
 delete mode 100644 avahi-daemon/sd-daemon.c
 delete mode 100644 avahi-daemon/sd-daemon.h

diff --git a/avahi-daemon/Makefile.am b/avahi-daemon/Makefile.am
index 9645e6e..a2e4afe 100644
--- a/avahi-daemon/Makefile.am
+++ b/avahi-daemon/Makefile.am
@@ -52,11 +52,10 @@ avahi_daemon_SOURCES = \
 	static-hosts.c static-hosts.h \
 	ini-file-parser.c ini-file-parser.h \
 	setproctitle.c setproctitle.h \
-	sd-daemon.h sd-daemon.c \
 	../avahi-client/check-nss.c
 
-avahi_daemon_CFLAGS = $(AM_CFLAGS) $(LIBDAEMON_CFLAGS) $(XML_CFLAGS)
-avahi_daemon_LDADD = $(AM_LDADD) ../avahi-common/libavahi-common.la ../avahi-core/libavahi-core.la $(LIBDAEMON_LIBS) $(XML_LIBS)
+avahi_daemon_CFLAGS = $(AM_CFLAGS) $(LIBDAEMON_CFLAGS) $(XML_CFLAGS) $(LIBSYSTEMD_CFLAGS)
+avahi_daemon_LDADD = $(AM_LDADD) ../avahi-common/libavahi-common.la ../avahi-core/libavahi-core.la $(LIBDAEMON_LIBS) $(XML_LIBS) $(LIBSYSTEMD_LIBS)
 
 ini_file_parser_test_SOURCES = \
 	ini-file-parser.c ini-file-parser.h \
@@ -170,7 +169,3 @@ xmllint:
 
 install-data-local:
 	test -z "$(avahi_runtime_dir)" || $(MKDIR_P) "$(DESTDIR)$(avahi_runtime_dir)"
-
-update-systemd:
-	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c > sd-daemon.c
-	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h > sd-daemon.h
diff --git a/avahi-daemon/main.c b/avahi-daemon/main.c
index 346338f..154d65b 100644
--- a/avahi-daemon/main.c
+++ b/avahi-daemon/main.c
@@ -53,6 +53,10 @@
 #include <unistd.h>
 #endif
 
+#ifdef HAVE_LIBSYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 #include <libdaemon/dfork.h>
 #include <libdaemon/dsignal.h>
 #include <libdaemon/dlog.h>
@@ -81,7 +85,6 @@
 #include "static-services.h"
 #include "static-hosts.h"
 #include "ini-file-parser.h"
-#include "sd-daemon.h"
 
 #ifdef HAVE_DBUS
 #include "dbus-protocol.h"
@@ -358,7 +361,9 @@ static void server_callback(AvahiServer *s, AvahiServerState state, void *userda
     switch (state) {
         case AVAHI_SERVER_RUNNING:
             avahi_log_info("Server startup complete. Host name is %s. Local service cookie is %u.", avahi_server_get_host_name_fqdn(s), avahi_server_get_local_service_cookie(s));
+#ifdef HAVE_LIBSYSTEMD
             sd_notifyf(0, "STATUS=Server startup complete. Host name is %s. Local service cookie is %u.", avahi_server_get_host_name_fqdn(s), avahi_server_get_local_service_cookie(s));
+#endif
             avahi_set_proc_title(argv0, "%s: running [%s]", argv0, avahi_server_get_host_name_fqdn(s));
 
             static_service_add_to_server();
@@ -385,7 +390,9 @@ static void server_callback(AvahiServer *s, AvahiServerState state, void *userda
             n = avahi_alternative_host_name(avahi_server_get_host_name(s));
 
             avahi_log_warn("Host name conflict, retrying with %s", n);
+#ifdef HAVE_LIBSYSTEMD
             sd_notifyf(0, "STATUS=Host name conflict, retrying with %s", n);
+#endif
             avahi_set_proc_title(argv0, "%s: collision [%s]", argv0, n);
 
             avahi_server_set_host_name(s, n);
@@ -397,14 +404,18 @@ static void server_callback(AvahiServer *s, AvahiServerState state, void *userda
         case AVAHI_SERVER_FAILURE:
 
             avahi_log_error("Server error: %s", avahi_strerror(avahi_server_errno(s)));
+#ifdef HAVE_LIBSYSTEMD
             sd_notifyf(0, "STATUS=Server error: %s", avahi_strerror(avahi_server_errno(s)));
+#endif
 
             avahi_simple_poll_quit(simple_poll_api);
             break;
 
         case AVAHI_SERVER_REGISTERING:
 
+#ifdef HAVE_LIBSYSTEMD
             sd_notifyf(0, "STATUS=Registering host name %s", avahi_server_get_host_name_fqdn(s));
+#endif
             avahi_set_proc_title(argv0, "%s: registering [%s]", argv0, avahi_server_get_host_name_fqdn(s));
 
             static_service_remove_from_server();
@@ -1631,9 +1642,11 @@ int main(int argc, char *argv[]) {
         if (config.use_syslog || config.daemonize)
             daemon_log_use = DAEMON_LOG_SYSLOG;
 
+#ifdef HAVE_LIBSYSTEMD
         if (sd_listen_fds(0) <= 0)
             if (daemon_close_all(-1) < 0)
                 avahi_log_warn("Failed to close all remaining file descriptors: %s", strerror(errno));
+#endif
 
         daemon_reset_sigs(-1);
         daemon_unblock_sigs(-1);
@@ -1680,14 +1693,18 @@ int main(int argc, char *argv[]) {
             }
 #endif
         avahi_log_info("%s "PACKAGE_VERSION" starting up.", argv0);
+#ifdef HAVE_LIBSYSTEMD
         sd_notifyf(0, "STATUS=%s "PACKAGE_VERSION" starting up.", argv0);
+#endif
         avahi_set_proc_title(argv0, "%s: starting up", argv0);
 
         if (run_server(&config) == 0)
             r = 0;
 
         avahi_log_info("%s "PACKAGE_VERSION" exiting.", argv0);
+#ifdef HAVE_LIBSYSTEMD
         sd_notifyf(0, "STATUS=%s "PACKAGE_VERSION" exiting.", argv0);
+#endif
     }
 
 finish:
diff --git a/avahi-daemon/sd-daemon.c b/avahi-daemon/sd-daemon.c
deleted file mode 100644
index 6d1eebf..0000000
--- a/avahi-daemon/sd-daemon.c
+++ /dev/null
@@ -1,436 +0,0 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
-  Copyright 2010 Lennart Poettering
-
-  Permission is hereby granted, free of charge, to any person
-  obtaining a copy of this software and associated documentation files
-  (the "Software"), to deal in the Software without restriction,
-  including without limitation the rights to use, copy, modify, merge,
-  publish, distribute, sublicense, and/or sell copies of the Software,
-  and to permit persons to whom the Software is furnished to do so,
-  subject to the following conditions:
-
-  The above copyright notice and this permission notice shall be
-  included in all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
-  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
-  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-***/
-
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-#include <sys/fcntl.h>
-#include <netinet/in.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdarg.h>
-#include <stdio.h>
-#include <stddef.h>
-
-#include "sd-daemon.h"
-
-int sd_listen_fds(int unset_environment) {
-
-#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
-        return 0;
-#else
-        int r, fd;
-        const char *e;
-        char *p = NULL;
-        unsigned long l;
-
-        if (!(e = getenv("LISTEN_PID"))) {
-                r = 0;
-                goto finish;
-        }
-
-        errno = 0;
-        l = strtoul(e, &p, 10);
-
-        if (errno != 0) {
-                r = -errno;
-                goto finish;
-        }
-
-        if (!p || *p || l <= 0) {
-                r = -EINVAL;
-                goto finish;
-        }
-
-        /* Is this for us? */
-        if (getpid() != (pid_t) l) {
-                r = 0;
-                goto finish;
-        }
-
-        if (!(e = getenv("LISTEN_FDS"))) {
-                r = 0;
-                goto finish;
-        }
-
-        errno = 0;
-        l = strtoul(e, &p, 10);
-
-        if (errno != 0) {
-                r = -errno;
-                goto finish;
-        }
-
-        if (!p || *p) {
-                r = -EINVAL;
-                goto finish;
-        }
-
-        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + (int) l; fd ++) {
-                int flags;
-
-                if ((flags = fcntl(fd, F_GETFD)) < 0) {
-                        r = -errno;
-                        goto finish;
-                }
-
-                if (flags & FD_CLOEXEC)
-                        continue;
-
-                if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
-                        r = -errno;
-                        goto finish;
-                }
-        }
-
-        r = (int) l;
-
-finish:
-        if (unset_environment) {
-                unsetenv("LISTEN_PID");
-                unsetenv("LISTEN_FDS");
-        }
-
-        return r;
-#endif
-}
-
-int sd_is_fifo(int fd, const char *path) {
-        struct stat st_fd;
-
-        if (fd < 0)
-                return -EINVAL;
-
-        memset(&st_fd, 0, sizeof(st_fd));
-        if (fstat(fd, &st_fd) < 0)
-                return -errno;
-
-        if (!S_ISFIFO(st_fd.st_mode))
-                return 0;
-
-        if (path) {
-                struct stat st_path;
-
-                memset(&st_path, 0, sizeof(st_path));
-                if (stat(path, &st_path) < 0) {
-
-                        if (errno == ENOENT || errno == ENOTDIR)
-                                return 0;
-
-                        return -errno;
-                }
-
-                return
-                        st_path.st_dev == st_fd.st_dev &&
-                        st_path.st_ino == st_fd.st_ino;
-        }
-
-        return 1;
-}
-
-static int sd_is_socket_internal(int fd, int type, int listening) {
-        struct stat st_fd;
-
-        if (fd < 0 || type < 0)
-                return -EINVAL;
-
-        if (fstat(fd, &st_fd) < 0)
-                return -errno;
-
-        if (!S_ISSOCK(st_fd.st_mode))
-                return 0;
-
-        if (type != 0) {
-                int other_type = 0;
-                socklen_t l = sizeof(other_type);
-
-                if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
-                        return -errno;
-
-                if (l != sizeof(other_type))
-                        return -EINVAL;
-
-                if (other_type != type)
-                        return 0;
-        }
-
-        if (listening >= 0) {
-                int accepting = 0;
-                socklen_t l = sizeof(accepting);
-
-                if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
-                        return -errno;
-
-                if (l != sizeof(accepting))
-                        return -EINVAL;
-
-                if (!accepting != !listening)
-                        return 0;
-        }
-
-        return 1;
-}
-
-union sockaddr_union {
-        struct sockaddr sa;
-        struct sockaddr_in in4;
-        struct sockaddr_in6 in6;
-        struct sockaddr_un un;
-        struct sockaddr_storage storage;
-};
-
-int sd_is_socket(int fd, int family, int type, int listening) {
-        int r;
-
-        if (family < 0)
-                return -EINVAL;
-
-        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
-                return r;
-
-        if (family > 0) {
-                union sockaddr_union sockaddr;
-                socklen_t l;
-
-                memset(&sockaddr, 0, sizeof(sockaddr));
-                l = sizeof(sockaddr);
-
-                if (getsockname(fd, &sockaddr.sa, &l) < 0)
-                        return -errno;
-
-                if (l < sizeof(sa_family_t))
-                        return -EINVAL;
-
-                return sockaddr.sa.sa_family == family;
-        }
-
-        return 1;
-}
-
-int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
-        union sockaddr_union sockaddr;
-        socklen_t l;
-        int r;
-
-        if (family != 0 && family != AF_INET && family != AF_INET6)
-                return -EINVAL;
-
-        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
-                return r;
-
-        memset(&sockaddr, 0, sizeof(sockaddr));
-        l = sizeof(sockaddr);
-
-        if (getsockname(fd, &sockaddr.sa, &l) < 0)
-                return -errno;
-
-        if (l < sizeof(sa_family_t))
-                return -EINVAL;
-
-        if (sockaddr.sa.sa_family != AF_INET &&
-            sockaddr.sa.sa_family != AF_INET6)
-                return 0;
-
-        if (family > 0)
-                if (sockaddr.sa.sa_family != family)
-                        return 0;
-
-        if (port > 0) {
-                if (sockaddr.sa.sa_family == AF_INET) {
-                        if (l < sizeof(struct sockaddr_in))
-                                return -EINVAL;
-
-                        return htons(port) == sockaddr.in4.sin_port;
-                } else {
-                        if (l < sizeof(struct sockaddr_in6))
-                                return -EINVAL;
-
-                        return htons(port) == sockaddr.in6.sin6_port;
-                }
-        }
-
-        return 1;
-}
-
-int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
-        union sockaddr_union sockaddr;
-        socklen_t l;
-        int r;
-
-        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
-                return r;
-
-        memset(&sockaddr, 0, sizeof(sockaddr));
-        l = sizeof(sockaddr);
-
-        if (getsockname(fd, &sockaddr.sa, &l) < 0)
-                return -errno;
-
-        if (l < sizeof(sa_family_t))
-                return -EINVAL;
-
-        if (sockaddr.sa.sa_family != AF_UNIX)
-                return 0;
-
-        if (path) {
-                if (length <= 0)
-                        length = strlen(path);
-
-                if (length <= 0)
-                        /* Unnamed socket */
-                        return l == offsetof(struct sockaddr_un, sun_path);
-
-                if (path[0])
-                        /* Normal path socket */
-                        return
-                                (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
-                                memcmp(path, sockaddr.un.sun_path, length+1) == 0;
-                else
-                        /* Abstract namespace socket */
-                        return
-                                (l == offsetof(struct sockaddr_un, sun_path) + length) &&
-                                memcmp(path, sockaddr.un.sun_path, length) == 0;
-        }
-
-        return 1;
-}
-
-int sd_notify(int unset_environment, const char *state) {
-#if defined(DISABLE_SYSTEMD) || !defined(__linux__) || !defined(SOCK_CLOEXEC)
-        return 0;
-#else
-        int fd = -1, r;
-        struct msghdr msghdr;
-        struct iovec iovec;
-        union sockaddr_union sockaddr;
-        const char *e;
-
-        if (!state) {
-                r = -EINVAL;
-                goto finish;
-        }
-
-        if (!(e = getenv("NOTIFY_SOCKET")))
-                return 0;
-
-        /* Must be an abstract socket, or an absolute path */
-        if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
-                r = -EINVAL;
-                goto finish;
-        }
-
-        if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
-                r = -errno;
-                goto finish;
-        }
-
-        memset(&sockaddr, 0, sizeof(sockaddr));
-        sockaddr.sa.sa_family = AF_UNIX;
-        strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
-
-        if (sockaddr.un.sun_path[0] == '@')
-                sockaddr.un.sun_path[0] = 0;
-
-        memset(&iovec, 0, sizeof(iovec));
-        iovec.iov_base = (char*) state;
-        iovec.iov_len = strlen(state);
-
-        memset(&msghdr, 0, sizeof(msghdr));
-        msghdr.msg_name = &sockaddr;
-        msghdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(e);
-
-        if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
-                msghdr.msg_namelen = sizeof(struct sockaddr_un);
-
-        msghdr.msg_iov = &iovec;
-        msghdr.msg_iovlen = 1;
-
-        if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) < 0) {
-                r = -errno;
-                goto finish;
-        }
-
-        r = 1;
-
-finish:
-        if (unset_environment)
-                unsetenv("NOTIFY_SOCKET");
-
-        if (fd >= 0)
-                close(fd);
-
-        return r;
-#endif
-}
-
-int sd_notifyf(int unset_environment, const char *format, ...) {
-#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
-        return 0;
-#else
-        va_list ap;
-        char *p = NULL;
-        int r;
-
-        va_start(ap, format);
-        r = vasprintf(&p, format, ap);
-        va_end(ap);
-
-        if (r < 0 || !p)
-                return -ENOMEM;
-
-        r = sd_notify(unset_environment, p);
-        free(p);
-
-        return r;
-#endif
-}
-
-int sd_booted(void) {
-#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
-        return 0;
-#else
-
-        struct stat a, b;
-
-        /* We simply test whether the systemd cgroup hierarchy is
-         * mounted */
-
-        if (lstat("/sys/fs/cgroup", &a) < 0)
-                return 0;
-
-        if (lstat("/sys/fs/cgroup/systemd", &b) < 0)
-                return 0;
-
-        return a.st_dev != b.st_dev;
-#endif
-}
diff --git a/avahi-daemon/sd-daemon.h b/avahi-daemon/sd-daemon.h
deleted file mode 100644
index 4b853a1..0000000
--- a/avahi-daemon/sd-daemon.h
+++ /dev/null
@@ -1,265 +0,0 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-#ifndef foosddaemonhfoo
-#define foosddaemonhfoo
-
-/***
-  Copyright 2010 Lennart Poettering
-
-  Permission is hereby granted, free of charge, to any person
-  obtaining a copy of this software and associated documentation files
-  (the "Software"), to deal in the Software without restriction,
-  including without limitation the rights to use, copy, modify, merge,
-  publish, distribute, sublicense, and/or sell copies of the Software,
-  and to permit persons to whom the Software is furnished to do so,
-  subject to the following conditions:
-
-  The above copyright notice and this permission notice shall be
-  included in all copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
-  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
-  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-  SOFTWARE.
-***/
-
-#include <sys/types.h>
-#include <inttypes.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/*
-  Reference implementation of a few systemd related interfaces for
-  writing daemons. These interfaces are trivial to implement. To
-  simplify porting we provide this reference implementation.
-  Applications are welcome to reimplement the algorithms described
-  here if they do not want to include these two source files.
-
-  The following functionality is provided:
-
-  - Support for logging with log levels on stderr
-  - File descriptor passing for socket-based activation
-  - Daemon startup and status notification
-  - Detection of systemd boots
-
-  You may compile this with -DDISABLE_SYSTEMD to disable systemd
-  support. This makes all those calls NOPs that are directly related to
-  systemd (i.e. only sd_is_xxx() will stay useful).
-
-  Since this is drop-in code we don't want any of our symbols to be
-  exported in any case. Hence we declare hidden visibility for all of
-  them.
-
-  You may find an up-to-date version of these source files online:
-
-  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h
-  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c
-
-  This should compile on non-Linux systems, too, but with the
-  exception of the sd_is_xxx() calls all functions will become NOPs.
-
-  See sd-daemon(7) for more information.
-*/
-
-#ifndef _sd_printf_attr_
-#if __GNUC__ >= 4
-#define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b)))
-#else
-#define _sd_printf_attr_(a,b)
-#endif
-#endif
-
-#ifndef _sd_hidden_
-#if (__GNUC__ >= 4) && !defined(SD_EXPORT_SYMBOLS)
-#define _sd_hidden_ __attribute__ ((visibility("hidden")))
-#else
-#define _sd_hidden_
-#endif
-#endif
-
-/*
-  Log levels for usage on stderr:
-
-          fprintf(stderr, SD_NOTICE "Hello World!\n");
-
-  This is similar to printk() usage in the kernel.
-*/
-#define SD_EMERG   "<0>"  /* system is unusable */
-#define SD_ALERT   "<1>"  /* action must be taken immediately */
-#define SD_CRIT    "<2>"  /* critical conditions */
-#define SD_ERR     "<3>"  /* error conditions */
-#define SD_WARNING "<4>"  /* warning conditions */
-#define SD_NOTICE  "<5>"  /* normal but significant condition */
-#define SD_INFO    "<6>"  /* informational */
-#define SD_DEBUG   "<7>"  /* debug-level messages */
-
-/* The first passed file descriptor is fd 3 */
-#define SD_LISTEN_FDS_START 3
-
-/*
-  Returns how many file descriptors have been passed, or a negative
-  errno code on failure. Optionally, removes the $LISTEN_FDS and
-  $LISTEN_PID file descriptors from the environment (recommended, but
-  problematic in threaded environments). If r is the return value of
-  this function you'll find the file descriptors passed as fds
-  SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
-  errno style error code on failure. This function call ensures that
-  the FD_CLOEXEC flag is set for the passed file descriptors, to make
-  sure they are not passed on to child processes. If FD_CLOEXEC shall
-  not be set, the caller needs to unset it after this call for all file
-  descriptors that are used.
-
-  See sd_listen_fds(3) for more information.
-*/
-int sd_listen_fds(int unset_environment) _sd_hidden_;
-
-/*
-  Helper call for identifying a passed file descriptor. Returns 1 if
-  the file descriptor is a FIFO in the file system stored under the
-  specified path, 0 otherwise. If path is NULL a path name check will
-  not be done and the call only verifies if the file descriptor
-  refers to a FIFO. Returns a negative errno style error code on
-  failure.
-
-  See sd_is_fifo(3) for more information.
-*/
-int sd_is_fifo(int fd, const char *path) _sd_hidden_;
-
-/*
-  Helper call for identifying a passed file descriptor. Returns 1 if
-  the file descriptor is a socket of the specified family (AF_INET,
-  ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
-  family is 0 a socket family check will not be done. If type is 0 a
-  socket type check will not be done and the call only verifies if
-  the file descriptor refers to a socket. If listening is > 0 it is
-  verified that the socket is in listening mode. (i.e. listen() has
-  been called) If listening is == 0 it is verified that the socket is
-  not in listening mode. If listening is < 0 no listening mode check
-  is done. Returns a negative errno style error code on failure.
-
-  See sd_is_socket(3) for more information.
-*/
-int sd_is_socket(int fd, int family, int type, int listening) _sd_hidden_;
-
-/*
-  Helper call for identifying a passed file descriptor. Returns 1 if
-  the file descriptor is an Internet socket, of the specified family
-  (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
-  SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
-  check is not done. If type is 0 a socket type check will not be
-  done. If port is 0 a socket port check will not be done. The
-  listening flag is used the same way as in sd_is_socket(). Returns a
-  negative errno style error code on failure.
-
-  See sd_is_socket_inet(3) for more information.
-*/
-int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) _sd_hidden_;
-
-/*
-  Helper call for identifying a passed file descriptor. Returns 1 if
-  the file descriptor is an AF_UNIX socket of the specified type
-  (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
-  a socket type check will not be done. If path is NULL a socket path
-  check will not be done. For normal AF_UNIX sockets set length to
-  0. For abstract namespace sockets set length to the length of the
-  socket name (including the initial 0 byte), and pass the full
-  socket path in path (including the initial 0 byte). The listening
-  flag is used the same way as in sd_is_socket(). Returns a negative
-  errno style error code on failure.
-
-  See sd_is_socket_unix(3) for more information.
-*/
-int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) _sd_hidden_;
-
-/*
-  Informs systemd about changed daemon state. This takes a number of
-  newline separated environment-style variable assignments in a
-  string. The following variables are known:
-
-     READY=1      Tells systemd that daemon startup is finished (only
-                  relevant for services of Type=notify). The passed
-                  argument is a boolean "1" or "0". Since there is
-                  little value in signaling non-readiness the only
-                  value daemons should send is "READY=1".
-
-     STATUS=...   Passes a single-line status string back to systemd
-                  that describes the daemon state. This is free-from
-                  and can be used for various purposes: general state
-                  feedback, fsck-like programs could pass completion
-                  percentages and failing programs could pass a human
-                  readable error message. Example: "STATUS=Completed
-                  66% of file system check..."
-
-     ERRNO=...    If a daemon fails, the errno-style error code,
-                  formatted as string. Example: "ERRNO=2" for ENOENT.
-
-     BUSERROR=... If a daemon fails, the D-Bus error-style error
-                  code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
-
-     MAINPID=...  The main pid of a daemon, in case systemd did not
-                  fork off the process itself. Example: "MAINPID=4711"
-
-  Daemons can choose to send additional variables. However, it is
-  recommended to prefix variable names not listed above with X_.
-
-  Returns a negative errno-style error code on failure. Returns > 0
-  if systemd could be notified, 0 if it couldn't possibly because
-  systemd is not running.
-
-  Example: When a daemon finished starting up, it could issue this
-  call to notify systemd about it:
-
-     sd_notify(0, "READY=1");
-
-  See sd_notifyf() for more complete examples.
-
-  See sd_notify(3) for more information.
-*/
-int sd_notify(int unset_environment, const char *state) _sd_hidden_;
-
-/*
-  Similar to sd_notify() but takes a format string.
-
-  Example 1: A daemon could send the following after initialization:
-
-     sd_notifyf(0, "READY=1\n"
-                   "STATUS=Processing requests...\n"
-                   "MAINPID=%lu",
-                   (unsigned long) getpid());
-
-  Example 2: A daemon could send the following shortly before
-  exiting, on failure:
-
-     sd_notifyf(0, "STATUS=Failed to start up: %s\n"
-                   "ERRNO=%i",
-                   strerror(errno),
-                   errno);
-
-  See sd_notifyf(3) for more information.
-*/
-int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3) _sd_hidden_;
-
-/*
-  Returns > 0 if the system was booted with systemd. Returns < 0 on
-  error. Returns 0 if the system was not booted with systemd. Note
-  that all of the functions above handle non-systemd boots just
-  fine. You should NOT protect them with a call to this function. Also
-  note that this function checks whether the system, not the user
-  session is controlled by systemd. However the functions above work
-  for both user and system services.
-
-  See sd_booted(3) for more information.
-*/
-int sd_booted(void) _sd_hidden_;
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
diff --git a/avahi-daemon/simple-protocol.c b/avahi-daemon/simple-protocol.c
index 6c0274d..829d34a 100644
--- a/avahi-daemon/simple-protocol.c
+++ b/avahi-daemon/simple-protocol.c
@@ -32,6 +32,10 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 
+#ifdef HAVE_LIBSYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 #include <avahi-common/llist.h>
 #include <avahi-common/malloc.h>
 #include <avahi-common/error.h>
@@ -42,7 +46,6 @@
 
 #include "simple-protocol.h"
 #include "main.h"
-#include "sd-daemon.h"
 
 #ifdef ENABLE_CHROOT
 #include "chroot.h"
@@ -453,7 +456,9 @@ static void server_work(AVAHI_GCC_UNUSED AvahiWatch *watch, int fd, AvahiWatchEv
 int simple_protocol_setup(const AvahiPoll *poll_api) {
     struct sockaddr_un sa;
     mode_t u;
+#ifdef HAVE_LIBSYSTEMD
     int n;
+#endif
 
     assert(!server);
 
@@ -467,6 +472,7 @@ int simple_protocol_setup(const AvahiPoll *poll_api) {
 
     u = umask(0000);
 
+#ifdef HAVE_LIBSYSTEMD
     if ((n = sd_listen_fds(1)) < 0) {
         avahi_log_warn("Failed to acquire systemd file descriptors: %s", strerror(-n));
         goto fail;
@@ -487,7 +493,9 @@ int simple_protocol_setup(const AvahiPoll *poll_api) {
 
         server->fd = SD_LISTEN_FDS_START;
 
-    } else {
+    } else
+#endif
+    {
 
         if ((server->fd = socket(AF_LOCAL, SOCK_STREAM, 0)) < 0) {
             avahi_log_warn("socket(AF_LOCAL, SOCK_STREAM, 0): %s", strerror(errno));
diff --git a/configure.ac b/configure.ac
index a1c2df4..584b9c1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -824,6 +824,26 @@ if test "x$HAVE_LIBDAEMON" = "xyes" ; then
 fi
 AM_CONDITIONAL(HAVE_LIBDAEMON, test "x$HAVE_LIBDAEMON" = "xyes")
 
+#
+# libsystemd
+#
+AC_ARG_ENABLE(libsystemd,
+        AS_HELP_STRING([--disable-libsystemd],[Disable use of libsystemd]),
+        [case "${enableval}" in
+                yes) HAVE_LIBSYSTEMD=yes ;;
+                no)  HAVE_LIBSYSTEMD=no ;;
+                *) AC_MSG_ERROR(bad value ${enableval} for --enable-libsystemd) ;;
+        esac],
+        [HAVE_LIBSYSTEMD=yes])
+
+if test "x$HAVE_LIBSYSTEMD" = "xyes" ; then
+    PKG_CHECK_MODULES(LIBSYSTEMD, [ libsystemd ])
+    AC_DEFINE([HAVE_LIBSYSTEMD], 1, [Support for libsystemd])
+    AC_SUBST(LIBSYSTEMD_CFLAGS)
+    AC_SUBST(LIBSYSTEMD_LIBS)
+fi
+AM_CONDITIONAL(HAVE_LIBSYSTEMD, test "x$HAVE_LIBSYSTEMD" = "xyes")
+
 #
 # Python stuff
 #
@@ -1205,6 +1225,7 @@ echo "
     Enable GDBM:                               ${HAVE_GDBM}
     Enable DBM:                                ${HAVE_DBM}
     Enable libdaemon:                          ${HAVE_LIBDAEMON}
+    Enable libsystemd:                         ${HAVE_LIBSYSTEMD}
     Enable Python:                             ${HAVE_PYTHON}
     Enable pygobject:                          ${HAVE_PYGOBJECT}
     Enable python-dbus:                        ${HAVE_PYTHON_DBUS}