syslog: rework syslog detection so that we need no compile-time option what the name of the syslog implementation is

Makefile.am

@@ -1102,7 +1102,6 @@ SED_PROCESS = \
 	$(SED)  -e 's,@rootlibexecdir\@,$(rootlibexecdir),g' \
                 -e 's,@rootbindir\@,$(rootbindir),g' \
                 -e 's,@bindir\@,$(bindir),g' \
-		-e 's,@SPECIAL_SYSLOG_SERVICE\@,$(SPECIAL_SYSLOG_SERVICE),g' \
 		-e 's,@SYSTEMCTL\@,$(rootbindir)/systemctl,g' \
 		-e 's,@SYSTEMD_NOTIFY\@,$(rootbindir)/systemd-notify,g' \
 		-e 's,@pkgsysconfdir\@,$(pkgsysconfdir),g' \

TODO

@@ -29,6 +29,8 @@ F15:
 
 * pull in .service from meta .targers AND vice versa too. i.e. syslog.target ←→ rsyslog.service, rpcbind similarly
 
+* document default dependencies
+
 Features:
 
 * hide passwords on TAB

configure.ac

@@ -297,30 +297,15 @@ fi
 with_distro=`echo ${with_distro} | tr '[[:upper:]]' '[[:lower:]]' `
 AC_DEFINE_UNQUOTED(DISTRIBUTION, ["${with_distro}"], [Target Distribution])
 
-# Default generic names
-SPECIAL_SYSLOG_SERVICE=syslog.service
-
 # Location of the init scripts as mandated by LSB
 SYSTEM_SYSVINIT_PATH=/etc/init.d
+SYSTEM_SYSVRCND_PATH=/etc/rc.d
 
 M4_DISTRO_FLAG=
 
 case $with_distro in
         fedora)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d/init.d
-                SYSTEM_SYSVRCND_PATH=/etc/rc.d
-
-                # A little background why we define this special unit
-                # names here in configure.ac: SysV services currently
-                # cannot have aliases. As long as syslog is started
-                # via a SysV init script we hence define this name to
-                # the actual SysV name here. Later on when SysV init
-                # scripts are not used anymore it is advisable to use
-                # the generic name instead and use symlinks in the
-                # unit directories to point to the right native unit
-                # file.
-
-                SPECIAL_SYSLOG_SERVICE=rsyslog.service
                 AC_DEFINE(TARGET_FEDORA, [], [Target is Fedora/RHEL])
                 M4_DISTRO_FLAG=-DTARGET_FEDORA=1
 		have_plymouth=true
@@ -333,61 +318,49 @@ case $with_distro in
                 ;;
         debian)
                 SYSTEM_SYSVRCND_PATH=/etc
-                SPECIAL_SYSLOG_SERVICE=rsyslog.service
                 AC_DEFINE(TARGET_DEBIAN, [], [Target is Debian])
                 M4_DISTRO_FLAG=-DTARGET_DEBIAN=1
                 ;;
         ubuntu)
                 SYSTEM_SYSVRCND_PATH=/etc
-                SPECIAL_SYSLOG_SERVICE=rsyslog.service
                 AC_DEFINE(TARGET_UBUNTU, [], [Target is Ubuntu])
                 M4_DISTRO_FLAG=-DTARGET_UBUNTU=1
                 ;;
         arch)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d
                 SYSTEM_SYSVRCND_PATH=/etc
-                SPECIAL_SYSLOG_SERVICE=syslog-ng.service
                 AC_DEFINE(TARGET_ARCH, [], [Target is ArchLinux])
                 M4_DISTRO_FLAG=-DTARGET_ARCH=1
                 ;;
         gentoo)
                 SYSTEM_SYSVINIT_PATH=
                 SYSTEM_SYSVRCND_PATH=
-                SPECIAL_SYSLOG_SERVICE=syslog-ng.service
                 AC_DEFINE(TARGET_GENTOO, [], [Target is Gentoo])
                 M4_DISTRO_FLAG=-DTARGET_GENTOO=1
                 ;;
         slackware)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d/init.d
-                SYSTEM_SYSVRCND_PATH=/etc/rc.d
                 AC_DEFINE(TARGET_SLACKWARE, [], [Target is Slackware])
                 M4_DISTRO_FLAG=-DTARGET_SLACKWARE=1
                 ;;
         frugalware)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d
-                SYSTEM_SYSVRCND_PATH=/etc/rc.d
                 AC_DEFINE(TARGET_FRUGALWARE, [], [Target is Frugalware])
                 M4_DISTRO_FLAG=-DTARGET_FRUGALWARE=1
                 ;;
         altlinux)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d/init.d
-                SYSTEM_SYSVRCND_PATH=/etc/rc.d
-                SPECIAL_SYSLOG_SERVICE=syslogd.service
                 AC_DEFINE(TARGET_ALTLINUX, [], [Target is ALTLinux])
                 M4_DISTRO_FLAG=-DTARGET_ALTLINUX=1
 		have_plymouth=true
                 ;;
         mandriva)
                 SYSTEM_SYSVINIT_PATH=/etc/rc.d/init.d
-                SYSTEM_SYSVRCND_PATH=/etc/rc.d
-                SPECIAL_SYSLOG_SERVICE=rsyslog.service
                 AC_DEFINE(TARGET_MANDRIVA, [], [Target is Mandriva])
                 M4_DISTRO_FLAG=-DTARGET_MANDRIVA=1
 		have_plymouth=true
                 ;;
         other)
-                AS_IF([test "x$with_syslog_service" = "x"],
-                        [AC_MSG_ERROR([With --distro=other, you must pass --with-syslog-service= to configure])])
                 ;;
         *)
                 AC_MSG_ERROR([Your distribution (${with_distro}) is not yet supported, SysV init scripts could not be found! (patches welcome); you can specify --with-distro=other to skip this check])
@@ -406,15 +379,8 @@ AC_ARG_WITH([sysvrcd-path],
         [SYSTEM_SYSVRCND_PATH="$withval"],
         [])
 
-AC_ARG_WITH([syslog-service],
-        [AS_HELP_STRING([--with-syslog-service=UNIT],
-                [Specify the name of the special syslog service @<:@default=based on distro@:>@])],
-        [SPECIAL_SYSLOG_SERVICE="$withval"],
-        [])
-
 AC_SUBST(SYSTEM_SYSVINIT_PATH)
 AC_SUBST(SYSTEM_SYSVRCND_PATH)
-AC_SUBST(SPECIAL_SYSLOG_SERVICE)
 AC_SUBST(M4_DISTRO_FLAG)
 
 if test "x${SYSTEM_SYSVINIT_PATH}" != "x" -a "x${SYSTEM_SYSVRCND_PATH}" != "x"; then
@@ -446,8 +412,6 @@ AM_CONDITIONAL(TARGET_MANDRIVA, test x"$with_distro" = xmandriva)
 
 AM_CONDITIONAL(HAVE_PLYMOUTH, test -n "$have_plymouth")
 
-AC_DEFINE_UNQUOTED(SPECIAL_SYSLOG_SERVICE, ["$SPECIAL_SYSLOG_SERVICE"], [Syslog service name])
-
 AC_ARG_WITH([dbuspolicydir],
         AS_HELP_STRING([--with-dbuspolicydir=DIR], [D-Bus policy directory]),
         [],
@@ -501,7 +465,6 @@ echo "
         SysV compatibility:      ${SYSTEM_SYSV_COMPAT}
         SysV init scripts:       ${SYSTEM_SYSVINIT_PATH}
         SysV rc?.d directories:  ${SYSTEM_SYSVRCND_PATH}
-        Syslog service:          ${SPECIAL_SYSLOG_SERVICE}
         Gtk:                     ${have_gtk}
         libcryptsetup:           ${have_libcryptsetup}
         tcpwrap:                 ${have_tcpwrap}

man/systemd.special.xml.in

@@ -78,7 +78,6 @@
                 <filename>sockets.target</filename>,
                 <filename>swap.target</filename>,
                 <filename>sysinit.target</filename>,
-                <filename>@SPECIAL_SYSLOG_SERVICE@</filename>,
                 <filename>syslog.target</filename>,
                 <filename>systemd-initctl.service</filename>,
                 <filename>systemd-initctl.socket</filename>,
@@ -542,27 +541,6 @@
                                         or b.</para>
                                 </listitem>
                         </varlistentry>
-                        <varlistentry>
-                                <term><filename>@SPECIAL_SYSLOG_SERVICE@</filename></term>
-                                <listitem>
-                                        <para>A special unit for the
-                                        syslog daemon. As soon as
-                                        this service is fully started
-                                        up systemd will connect to it
-                                        and use it for logging if it
-                                        has been configured for
-                                        that.</para>
-
-                                        <para>Units should generally
-                                        avoid depending on this unit
-                                        directly and instead refer to
-                                        the
-                                        <filename>syslog.target</filename>
-                                        unit instead, which pulls this
-                                        one in directly or indirectly
-                                        via socket-based activation.</para>
-                                </listitem>
-                        </varlistentry>
                         <varlistentry>
                                 <term><filename>syslog.target</filename></term>
                                 <listitem>
@@ -574,15 +552,6 @@
                                         referring to the
                                         <literal>$syslog</literal>
                                         facility.</para>
-
-                                        <para>Administrators should
-                                        ensure that this target pulls
-                                        in a service unit with the
-                                        name or alias of
-                                        <filename>@SPECIAL_SYSLOG_SERVICE@</filename>
-                                        (or a socket unit that
-                                        activates this
-                                        service).</para>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>

src/manager.c

@@ -2451,6 +2451,12 @@ void manager_send_unit_audit(Manager *m, Unit *u, int type, bool success) {
         if (m->n_deserializing > 0)
                 return;
 
+        if (m->running_as != MANAGER_SYSTEM)
+                return;
+
+        if (u->meta.type != UNIT_SERVICE)
+                return;
+
         if (!(p = unit_name_to_prefix_and_instance(u->meta.id))) {
                 log_error("Failed to allocate unit name for audit message: %s", strerror(ENOMEM));
                 return;
@@ -2965,6 +2971,47 @@ int manager_set_default_controllers(Manager *m, char **controllers) {
         return 0;
 }
 
+void manager_recheck_syslog(Manager *m) {
+        Unit *u;
+
+        assert(m);
+
+        if (m->running_as != MANAGER_SYSTEM)
+                return;
+
+        if ((u = manager_get_unit(m, SPECIAL_SYSLOG_SOCKET))) {
+                SocketState state;
+
+                state = SOCKET(u)->state;
+
+                if (state != SOCKET_DEAD &&
+                    state != SOCKET_FAILED &&
+                    state != SOCKET_RUNNING) {
+
+                        /* Hmm, the socket is not set up, or is still
+                         * listening, let's better not try to use
+                         * it. Note that we have no problem if the
+                         * socket is completely down, since there
+                         * might be a foreign /dev/log socket around
+                         * and we want to make use of that.
+                         */
+
+                        log_close_syslog();
+                        return;
+                }
+        }
+
+        if ((u = manager_get_unit(m, SPECIAL_SYSLOG_TARGET)))
+                if (TARGET(u)->state != TARGET_ACTIVE) {
+                        log_close_syslog();
+                        return;
+                }
+
+        /* Hmm, OK, so the socket is either fully up, or fully down,
+         * and the target is up, then let's make use of the socket */
+        log_open();
+}
+
 static const char* const manager_running_as_table[_MANAGER_RUNNING_AS_MAX] = {
         [MANAGER_SYSTEM] = "system",
         [MANAGER_USER] = "user"

src/manager.h

@@ -285,6 +285,8 @@ void manager_check_finished(Manager *m);
 void manager_run_generators(Manager *m);
 void manager_undo_generators(Manager *m);
 
+void manager_recheck_syslog(Manager *m);
+
 const char *manager_running_as_to_string(ManagerRunningAs i);
 ManagerRunningAs manager_running_as_from_string(const char *s);
 

src/special.h

@@ -24,21 +24,24 @@
 
 #define SPECIAL_DEFAULT_TARGET "default.target"
 
+/* Shutdown targets */
+#define SPECIAL_UMOUNT_TARGET "umount.target"
 /* This is not really intended to be started by directly. This is
  * mostly so that other targets (reboot/halt/poweroff) can depend on
  * it to bring all services down that want to be brought down on
  * system shutdown. */
 #define SPECIAL_SHUTDOWN_TARGET "shutdown.target"
-#define SPECIAL_UMOUNT_TARGET "umount.target"
 #define SPECIAL_HALT_TARGET "halt.target"
 #define SPECIAL_POWEROFF_TARGET "poweroff.target"
 #define SPECIAL_REBOOT_TARGET "reboot.target"
 #define SPECIAL_KEXEC_TARGET "kexec.target"
 #define SPECIAL_EXIT_TARGET "exit.target"
 
+/* Special boot targets */
 #define SPECIAL_RESCUE_TARGET "rescue.target"
 #define SPECIAL_EMERGENCY_TARGET "emergency.target"
 
+/* Early boot targets */
 #define SPECIAL_SYSINIT_TARGET "sysinit.target"
 #define SPECIAL_SOCKETS_TARGET "sockets.target"
 #define SPECIAL_LOCAL_FS_TARGET "local-fs.target"         /* LSB's $local_fs */
@@ -46,8 +49,8 @@
 #define SPECIAL_SWAP_TARGET "swap.target"
 #define SPECIAL_BASIC_TARGET "basic.target"
 
+/* LSB compatibility */
 #define SPECIAL_NETWORK_TARGET "network.target"           /* LSB's $network */
-
 #define SPECIAL_NSS_LOOKUP_TARGET "nss-lookup.target"     /* LSB's $named */
 #define SPECIAL_RPCBIND_TARGET "rpcbind.target"           /* LSB's $portmap */
 #define SPECIAL_SYSLOG_TARGET "syslog.target"             /* LSB's $syslog; Should pull in syslog.socket or syslog.service */
@@ -56,22 +59,22 @@
 #define SPECIAL_MAIL_TRANSFER_AGENT_TARGET "mail-transfer-agent.target" /* Debian's $mail-{transport|transfer-agent */
 #define SPECIAL_HTTP_DAEMON_TARGET "http-daemon.target"
 
+/* Magic early boot services */
 #define SPECIAL_FSCK_SERVICE "fsck@.service"
 #define SPECIAL_QUOTACHECK_SERVICE "quotacheck.service"
 #define SPECIAL_REMOUNT_ROOTFS_SERVICE "remount-rootfs.service"
 
+/* Services systemd relies on */
 #define SPECIAL_DBUS_SERVICE "dbus.service"
 #define SPECIAL_DBUS_SOCKET "dbus.socket"
 #define SPECIAL_LOGGER_SOCKET "systemd-logger.socket"
+#define SPECIAL_SYSLOG_SOCKET "syslog.socket"
 
+/* Magic init signals */
 #define SPECIAL_KBREQUEST_TARGET "kbrequest.target"
 #define SPECIAL_SIGPWR_TARGET "sigpwr.target"
 #define SPECIAL_CTRL_ALT_DEL_TARGET "ctrl-alt-del.target"
 
-#ifndef SPECIAL_SYSLOG_SERVICE
-#define SPECIAL_SYSLOG_SERVICE "syslog.service"
-#endif
-
 /* For SysV compatibility. Usually an alias for a saner target. On
  * SysV-free systems this doesn't exist. */
 #define SPECIAL_RUNLEVEL2_TARGET "runlevel2.target"

src/unit.c

@@ -1224,12 +1224,6 @@ void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, bool reload_su
                          * yet connected. */
                         bus_init(u->meta.manager, true);
 
-                if (unit_has_name(u, SPECIAL_SYSLOG_SERVICE))
-                        /* The syslog daemon just might have become
-                         * available, hence try to connect to it, if
-                         * we aren't yet connected. */
-                        log_open();
-
                 if (u->meta.type == UNIT_SERVICE &&
                     !UNIT_IS_ACTIVE_OR_RELOADING(os)) {
                         /* Write audit record if we have just finished starting up */
@@ -1242,12 +1236,6 @@ void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, bool reload_su
 
         } else {
 
-                if (unit_has_name(u, SPECIAL_SYSLOG_SERVICE))
-                        /* The syslog daemon might just have
-                         * terminated, hence try to disconnect from
-                         * it. */
-                        log_close_syslog();
-
                 /* We don't care about D-Bus here, since we'll get an
                  * asynchronous notification for it anyway. */
 
@@ -1277,6 +1265,8 @@ void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, bool reload_su
 
         unit_add_to_dbus_queue(u);
         unit_add_to_gc_queue(u);
+
+        manager_recheck_syslog(u->meta.manager);
 }
 
 int unit_watch_fd(Unit *u, int fd, uint32_t events, Watch *w) {

units/syslog.target.in

@@ -9,9 +9,3 @@
 
 [Unit]
 Description=Syslog
-
-# As soon as all syslog services have native unit files this explicit
-# dependency should be dropped, and replaced by alias symlinks in the
-# .wants/ directory, to either the .service or .socket unit of the
-# syslog service.
-After=@SPECIAL_SYSLOG_SERVICE@