Merge pull request #8508 from opensourcerouting/systemd-no-lib

28 files changed, 151 insertions, 163 deletions

diff --git a/alpine/APKBUILD.in b/alpine/APKBUILD.in
index dfedf0b52b..e6776cb3a2 100644
--- a/alpine/APKBUILD.in
+++ b/alpine/APKBUILD.in
@@ -41,7 +41,6 @@ build() {
 		--sysconfdir=$_sysconfdir \
 		--libdir=$_libdir \
 		--localstatedir=$_localstatedir \
-		--enable-systemd=no \
 		--enable-rpki \
 		--enable-vtysh \
 		--enable-multipath=64 \
diff --git a/configure.ac b/configure.ac
index 6108a37522..a23011b755 100644
--- a/configure.ac
+++ b/configure.ac
@@ -672,8 +672,6 @@ AC_ARG_ENABLE([fpm],
   AS_HELP_STRING([--enable-fpm], [enable Forwarding Plane Manager support]))
 AC_ARG_ENABLE([pcep],
   AS_HELP_STRING([--enable-pcep], [enable PCEP support for pathd]))
-AC_ARG_ENABLE([systemd],
-  AS_HELP_STRING([--enable-systemd], [enable Systemd support]))
 AC_ARG_ENABLE([werror],
   AS_HELP_STRING([--enable-werror], [enable -Werror (recommended for developers only)]))
 AC_ARG_ENABLE([cumulus],
@@ -768,19 +766,6 @@ case "${enable_cpu_time}" in
   ;;
 esac
 
-case "${enable_systemd}" in
-  "no") ;;
-  "yes")
-  AC_CHECK_LIB([systemd], [sd_notify], [LIBS="$LIBS -lsystemd"])
-  if test "$ac_cv_lib_systemd_sd_notify" = "no"; then
-    AC_MSG_ERROR([enable systemd has been specified but systemd development env not found on your system])
-  else
-    AC_DEFINE([HAVE_SYSTEMD], [1], [Compile systemd support in])
-  fi
-  ;;
-  "*") ;;
-esac
-
 if test "$enable_rr_semantics" != "no" ; then
   AC_DEFINE([HAVE_V6_RR_SEMANTICS], [1], [Compile in v6 Route Replacement Semantics])
 fi
diff --git a/debian/README.Debian b/debian/README.Debian
index a23a0efcac..53fb6c9d0e 100644
--- a/debian/README.Debian
+++ b/debian/README.Debian
@@ -31,10 +31,6 @@ The following Build Profiles have been added:
   controls whether the RPKI module is built.
   Will be enabled by default at some point, adds some extra dependencies.
 
-- pkg.frr.nosystemd
-  Disables both systemd unit file installation as well as watchfrr sd_notify
-  support at startup.  Removes libsystemd dependency.
-
 Note that all options have a "no" form;  if you want to have your decision
 be sticky regardless of changes to what it defaults to, then always use one
 of the two.  For example, all occurrences of <pkg.frr.rtrlib> will at some
@@ -43,10 +39,6 @@ point be replaced with <!pkg.frr.nortrlib>.
 The main frr package has the exact same contents regardless of rtrlib or snmp
 choices.  The options only control frr-snmp and frr-rpki-rtrlib packages.
 
-The main frr package does NOT have the same contents if pkg.frr.nosystemd is
-used.  This option should only be used for systems that do not have systemd,
-e.g. Ubuntu 14.04.
-
 
 * Debian Policy compliance notes
 ================================
diff --git a/debian/control b/debian/control
index 0bbe99b312..0e67ff3730 100644
--- a/debian/control
+++ b/debian/control
@@ -22,7 +22,6 @@ Build-Depends: bison,
                librtr-dev <!pkg.frr.nortrlib>,
                libsnmp-dev,
                libssh-dev <!pkg.frr.nortrlib>,
-               libsystemd-dev <!pkg.frr.nosystemd>,
                libyang2-dev,
                lsb-base,
                pkg-config,
diff --git a/debian/rules b/debian/rules
index 93d0cdb2a0..0fa9c3a3b0 100755
--- a/debian/rules
+++ b/debian/rules
@@ -21,14 +21,6 @@ else
   CONF_RPKI=--disable-rpki
 endif
 
-ifeq ($(filter pkg.frr.nosystemd,$(DEB_BUILD_PROFILES)),)
-  DH_WITHOUT_SYSTEMD=
-  CONF_SYSTEMD=--enable-systemd=yes
-else
-  DH_WITHOUT_SYSTEMD=--without=systemd
-  CONF_SYSTEMD=--enable-systemd=no
-endif
-
 ifeq ($(filter pkg.frr.lua,$(DEB_BUILD_PROFILES)),)
   CONF_LUA=--disable-scripting
 else
@@ -38,7 +30,7 @@ endif
 export PYTHON=python3
 
 %:
-	dh $@ $(DH_WITHOUT_SYSTEMD)
+	dh $@
 
 override_dh_auto_configure:
 	$(shell dpkg-buildflags --export=sh); \
@@ -52,7 +44,6 @@ override_dh_auto_configure:
 		LIBTOOLFLAGS="-rpath /usr/lib/$(DEB_HOST_MULTIARCH)/frr" \
 		--disable-dependency-tracking \
 		\
-		$(CONF_SYSTEMD) \
 		$(CONF_RPKI) \
 		$(CONF_LUA) \
 		--with-libpam \
@@ -80,9 +71,7 @@ override_dh_auto_install:
 	sed -e '1c #!/usr/bin/python3' -i debian/tmp/usr/lib/frr/generate_support_bundle.py
 
 # let dh_systemd_* and dh_installinit do their thing automatically
-ifeq ($(filter pkg.frr.nosystemd,$(DEB_BUILD_PROFILES)),)
 	cp tools/frr.service debian/frr.service
-endif
 	cp tools/frrinit.sh debian/frr.init
 	-rm -f debian/tmp/usr/lib/frr/frr
 
diff --git a/doc/developer/building-frr-for-archlinux.rst b/doc/developer/building-frr-for-archlinux.rst
index e589a9f724..af1677e89e 100644
--- a/doc/developer/building-frr-for-archlinux.rst
+++ b/doc/developer/building-frr-for-archlinux.rst
@@ -10,8 +10,8 @@ Installing Dependencies
    sudo pacman -S \
       git autoconf automake libtool make cmake pcre readline texinfo \
       pkg-config pam json-c bison flex python-pytest \
-      c-ares python systemd python2-ipaddress python-sphinx \
-      systemd-libs net-snmp perl libcap libelf
+      c-ares python python2-ipaddress python-sphinx \
+      net-snmp perl libcap libelf
 
 .. include:: building-libyang.rst
 
diff --git a/doc/developer/building-frr-for-centos7.rst b/doc/developer/building-frr-for-centos7.rst
index 93b9993a38..ce11126f70 100644
--- a/doc/developer/building-frr-for-centos7.rst
+++ b/doc/developer/building-frr-for-centos7.rst
@@ -21,7 +21,7 @@ Add packages:
     sudo yum install git autoconf automake libtool make \
       readline-devel texinfo net-snmp-devel groff pkgconfig \
       json-c-devel pam-devel bison flex pytest c-ares-devel \
-      python-devel systemd-devel python-sphinx libcap-devel \
+      python-devel python-sphinx libcap-devel \
       elfutils-libelf-devel
 
 .. include:: building-libyang.rst
@@ -66,7 +66,6 @@ an example.)
         --enable-user=frr \
         --enable-group=frr \
         --enable-vty-group=frrvty \
-	--enable-systemd=yes \
         --disable-ldpd \
         --enable-fpm \
         --with-pkg-git-version \
diff --git a/doc/developer/building-frr-for-centos8.rst b/doc/developer/building-frr-for-centos8.rst
index 65c93286b7..109a7866d9 100644
--- a/doc/developer/building-frr-for-centos8.rst
+++ b/doc/developer/building-frr-for-centos8.rst
@@ -14,7 +14,7 @@ Add packages:
     sudo dnf install --enablerepo=PowerTools git autoconf pcre-devel \
       automake libtool make readline-devel texinfo net-snmp-devel pkgconfig \
       groff pkgconfig json-c-devel pam-devel bison flex python2-pytest \
-      c-ares-devel python2-devel systemd-devel libcap-devel \
+      c-ares-devel python2-devel libcap-devel \
       elfutils-libelf-devel
 
 .. include:: building-libyang.rst
@@ -59,7 +59,6 @@ an example.)
         --enable-user=frr \
         --enable-group=frr \
         --enable-vty-group=frrvty \
-	--enable-systemd=yes \
         --disable-ldpd \
         --enable-fpm \
         --with-pkg-git-version \
diff --git a/doc/developer/building-frr-for-debian8.rst b/doc/developer/building-frr-for-debian8.rst
index 475e0303fc..5e58854ed7 100644
--- a/doc/developer/building-frr-for-debian8.rst
+++ b/doc/developer/building-frr-for-debian8.rst
@@ -17,7 +17,7 @@ Add packages:
 
    sudo apt-get install git autoconf automake libtool make \
       libreadline-dev texinfo libjson-c-dev pkg-config bison flex python3-pip \
-      libc-ares-dev python3-dev python3-sphinx build-essential libsystemd-dev \
+      libc-ares-dev python3-dev python3-sphinx build-essential \
       libsnmp-dev libcap-dev libelf-dev
 
 Install newer pytest (>3.0) from pip
diff --git a/doc/developer/building-frr-for-debian9.rst b/doc/developer/building-frr-for-debian9.rst
index 1981127b3d..f8d8025f62 100644
--- a/doc/developer/building-frr-for-debian9.rst
+++ b/doc/developer/building-frr-for-debian9.rst
@@ -11,7 +11,7 @@ Add packages:
    sudo apt-get install git autoconf automake libtool make \
      libreadline-dev texinfo libjson-c-dev pkg-config bison flex \
      libc-ares-dev python3-dev python3-pytest python3-sphinx build-essential \
-     libsnmp-dev libsystemd-dev libcap-dev libelf-dev
+     libsnmp-dev libcap-dev libelf-dev
 
 .. include:: building-libyang.rst
 
diff --git a/doc/developer/building-frr-for-fedora.rst b/doc/developer/building-frr-for-fedora.rst
index 5fecd8a826..6ce76ba158 100644
--- a/doc/developer/building-frr-for-fedora.rst
+++ b/doc/developer/building-frr-for-fedora.rst
@@ -14,7 +14,7 @@ Installing Dependencies
    sudo dnf install git autoconf automake libtool make \
      readline-devel texinfo net-snmp-devel groff pkgconfig json-c-devel \
      pam-devel python3-pytest bison flex c-ares-devel python3-devel \
-     python3-sphinx perl-core patch systemd-devel libcap-devel \
+     python3-sphinx perl-core patch libcap-devel \
      elfutils-libelf-devel
 
 .. include:: building-libyang.rst
diff --git a/doc/developer/building-frr-for-opensuse.rst b/doc/developer/building-frr-for-opensuse.rst
index 4e886e9c25..ee6a36a14b 100644
--- a/doc/developer/building-frr-for-opensuse.rst
+++ b/doc/developer/building-frr-for-opensuse.rst
@@ -13,7 +13,7 @@ Installing Dependencies
    zypper in  git autoconf automake libtool make   \
      readline-devel texinfo net-snmp-devel groff pkgconfig libjson-c-devel\
      pam-devel python3-pytest bison flex c-ares-devel python3-devel\
-     python3-Sphinx perl patch systemd-devel libcap-devel libyang-devel \
+     python3-Sphinx perl patch libcap-devel libyang-devel \
      libelf-devel
 
 Building & Installing FRR
diff --git a/doc/developer/building-frr-for-ubuntu1604.rst b/doc/developer/building-frr-for-ubuntu1604.rst
index 2cb9536f9b..d79545c859 100644
--- a/doc/developer/building-frr-for-ubuntu1604.rst
+++ b/doc/developer/building-frr-for-ubuntu1604.rst
@@ -13,8 +13,8 @@ Installing Dependencies
    apt-get install \
       git autoconf automake libtool make libreadline-dev texinfo \
       pkg-config libpam0g-dev libjson-c-dev bison flex python3-pytest \
-      libc-ares-dev python3-dev libsystemd-dev python-ipaddress python3-sphinx \
-      install-info build-essential libsystemd-dev libsnmp-dev perl libcap-dev \
+      libc-ares-dev python3-dev python-ipaddress python3-sphinx \
+      install-info build-essential libsnmp-dev perl libcap-dev \
       libelf-dev
 
 .. include:: building-libyang.rst
diff --git a/doc/developer/building-frr-for-ubuntu1804.rst b/doc/developer/building-frr-for-ubuntu1804.rst
index eb3991c139..39a17fc01c 100644
--- a/doc/developer/building-frr-for-ubuntu1804.rst
+++ b/doc/developer/building-frr-for-ubuntu1804.rst
@@ -13,8 +13,8 @@ Installing Dependencies
    sudo apt-get install \
       git autoconf automake libtool make libreadline-dev texinfo \
       pkg-config libpam0g-dev libjson-c-dev bison flex python3-pytest \
-      libc-ares-dev python3-dev libsystemd-dev python-ipaddress python3-sphinx \
-      install-info build-essential libsystemd-dev libsnmp-dev perl libcap-dev \
+      libc-ares-dev python3-dev python-ipaddress python3-sphinx \
+      install-info build-essential libsnmp-dev perl libcap-dev \
       libelf-dev
 
 .. include:: building-libyang.rst
diff --git a/doc/developer/building-frr-for-ubuntu2004.rst b/doc/developer/building-frr-for-ubuntu2004.rst
index 58d72e2891..92ddead4a5 100644
--- a/doc/developer/building-frr-for-ubuntu2004.rst
+++ b/doc/developer/building-frr-for-ubuntu2004.rst
@@ -13,8 +13,8 @@ Installing Dependencies
    sudo apt-get install \
       git autoconf automake libtool make libreadline-dev texinfo \
       pkg-config libpam0g-dev libjson-c-dev bison flex python3-pytest \
-      libc-ares-dev python3-dev libsystemd-dev python-ipaddress python3-sphinx \
-      install-info build-essential libsystemd-dev libsnmp-dev perl \
+      libc-ares-dev python3-dev python-ipaddress python3-sphinx \
+      install-info build-essential libsnmp-dev perl \
       libcap-dev python2 libelf-dev
 
 Note that Ubuntu 20 no longer installs python 2.x, so it must be
diff --git a/doc/developer/include-compile.rst b/doc/developer/include-compile.rst
index d9fa260221..513cac6179 100644
--- a/doc/developer/include-compile.rst
+++ b/doc/developer/include-compile.rst
@@ -2,11 +2,6 @@ Clone the FRR git repo and use the included ``configure`` script to configure
 FRR's build time options to your liking. The full option listing can be
 obtained by running ``./configure -h``. The options shown below are examples.
 
-.. note::
-
-   If your platform uses ``systemd``, please make sure to add
-   ``--enable-systemd=yes`` to your configure options.
-
 .. code-block:: console
 
    git clone https://github.com/frrouting/frr.git frr
diff --git a/doc/developer/packaging-debian.rst b/doc/developer/packaging-debian.rst
index 968e960267..a81e052490 100644
--- a/doc/developer/packaging-debian.rst
+++ b/doc/developer/packaging-debian.rst
@@ -53,7 +53,7 @@ buster.)
    Where `$options` may contain any or all of the following items:
 
    * build profiles specified with ``-P``, e.g.
-     ``-Ppkg.frr.nortrlib,pkg.frr.nosystemd``.
+     ``-Ppkg.frr.nortrlib,pkg.frr.rtrlib``.
      Multiple values are separated by commas and there must not be a space
      after the ``-P``.
 
@@ -64,14 +64,6 @@ buster.)
      +================+===================+=========================================+
      | pkg.frr.rtrlib | pkg.frr.nortrlib  | builds frr-rpki-rtrlib package (or not) |
      +----------------+-------------------+-----------------------------------------+
-     | n/a            | pkg.frr.nosystemd | removes libsystemd dependency and       |
-     |                |                   | disables unit file installation         |
-     +----------------+-------------------+-----------------------------------------+
-
-     .. note::
-
-        The ``pkg.frr.nosystemd`` option is only intended to support Ubuntu
-        14.04 (and should be enabled when building for that.)
 
    * the ``-uc -us`` options to disable signing the packages with your GPG key
 
diff --git a/doc/developer/packaging-redhat.rst b/doc/developer/packaging-redhat.rst
index 458cfa0ad4..9e64b912f3 100644
--- a/doc/developer/packaging-redhat.rst
+++ b/doc/developer/packaging-redhat.rst
@@ -18,10 +18,6 @@ Tested on CentOS 6, CentOS 7, CentOS 8 and Fedora 24.
 
       yum install rpm-build net-snmp-devel pam-devel libcap-devel
 
-   If your platform uses systemd::
-
-      yum install systemd-devel
-
    For CentOS 7 and CentOS 8, the package will be built using python3
    and requires additional python3 packages::
 
diff --git a/doc/user/installation.rst b/doc/user/installation.rst
index 63254555d9..fdf5bab9c9 100644
--- a/doc/user/installation.rst
+++ b/doc/user/installation.rst
@@ -146,11 +146,6 @@ options from the list below.
    software available on your machine.  This is needed for systemd integration, if you
    disable watchfrr you cannot have any systemd integration.
 
-.. option:: --enable-systemd
-
-   Build watchfrr with systemd integration, this will allow FRR to communicate with
-   systemd to tell systemd if FRR has come up properly.
-
 .. option:: --enable-werror
 
    Build with all warnings converted to errors as a compile option.  This
@@ -404,6 +399,12 @@ options to the configuration script.
 
    Set StrongSWAN vici interface socket path [/var/run/charon.vici].
 
+.. note::
+
+   The former ``--enable-systemd`` option does not exist anymore.  Support for
+   systemd is now always available through built-in functions, without
+   depending on libsystemd.
+
 Python dependency, documentation and tests
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/docker/centos-7/Dockerfile b/docker/centos-7/Dockerfile
index 303a33fe4a..73097df8fa 100644
--- a/docker/centos-7/Dockerfile
+++ b/docker/centos-7/Dockerfile
@@ -4,7 +4,7 @@ RUN yum install -y epel-release
 RUN yum install -y rpm-build autoconf automake libtool make \
         readline-devel texinfo net-snmp-devel groff pkgconfig \
         json-c-devel pam-devel bison flex pytest c-ares-devel \
-        python3-devel python3-sphinx systemd-devel libcap-devel \
+        python3-devel python3-sphinx libcap-devel \
         https://ci1.netdef.org/artifact/LIBYANG-LIBYANGV2/shared/build-2/CentOS-7-x86_64-Packages/libyang2-2.0.0.10.g2eb910e4-1.el7.x86_64.rpm \
         https://ci1.netdef.org/artifact/LIBYANG-LIBYANGV2/shared/build-2/CentOS-7-x86_64-Packages/libyang2-devel-2.0.0.10.g2eb910e4-1.el7.x86_64.rpm \
         https://ci1.netdef.org/artifact/RPKI-RTRLIB/shared/build-110/CentOS-7-x86_64-Packages/librtr-0.7.0-1.el7.centos.x86_64.rpm \
diff --git a/docker/centos-8/Dockerfile b/docker/centos-8/Dockerfile
index 8a0c28e13b..71378c2451 100644
--- a/docker/centos-8/Dockerfile
+++ b/docker/centos-8/Dockerfile
@@ -4,7 +4,7 @@ FROM centos:centos8 as centos-8-builder
 RUN dnf install --enablerepo=powertools -y rpm-build git autoconf pcre-devel \
         automake libtool make readline-devel texinfo net-snmp-devel pkgconfig \
         groff pkgconfig json-c-devel pam-devel bison flex python3-pytest \
-        c-ares-devel python3-devel python3-sphinx systemd-devel libcap-devel platform-python-devel \
+        c-ares-devel python3-devel python3-sphinx libcap-devel platform-python-devel \
         https://ci1.netdef.org/artifact/LIBYANG-LIBYANGV2/shared/build-2/CentOS-8-x86_64-Packages/libyang2-2.0.0.10.g2eb910e4-1.el8.x86_64.rpm \
         https://ci1.netdef.org/artifact/LIBYANG-LIBYANGV2/shared/build-2/CentOS-8-x86_64-Packages/libyang2-devel-2.0.0.10.g2eb910e4-1.el8.x86_64.rpm \
         https://ci1.netdef.org/artifact/RPKI-RTRLIB/shared/build-110/CentOS-7-x86_64-Packages/librtr-0.7.0-1.el7.centos.x86_64.rpm \
diff --git a/docker/ubuntu18-ci/Dockerfile b/docker/ubuntu18-ci/Dockerfile
index 680b9172ad..766f06dfc2 100644
--- a/docker/ubuntu18-ci/Dockerfile
+++ b/docker/ubuntu18-ci/Dockerfile
@@ -7,8 +7,8 @@ RUN apt update && \
     apt-get install -y \
       git autoconf automake libtool make libreadline-dev texinfo \
       pkg-config libpam0g-dev libjson-c-dev bison flex python3-pytest \
-      libc-ares-dev python3-dev libsystemd-dev python-ipaddress python3-sphinx \
-      install-info build-essential libsystemd-dev libsnmp-dev perl libcap-dev \
+      libc-ares-dev python3-dev python-ipaddress python3-sphinx \
+      install-info build-essential libsnmp-dev perl libcap-dev \
       libelf-dev \
       sudo gdb iputils-ping time \
       mininet python-pip iproute2 iperf && \
diff --git a/docker/ubuntu20-ci/Dockerfile b/docker/ubuntu20-ci/Dockerfile
index 47d5b81d3a..b5df98f23e 100644
--- a/docker/ubuntu20-ci/Dockerfile
+++ b/docker/ubuntu20-ci/Dockerfile
@@ -7,8 +7,8 @@ RUN apt update && \
     apt-get install -y \
       git autoconf automake libtool make libreadline-dev texinfo \
       pkg-config libpam0g-dev libjson-c-dev bison flex python3-pytest \
-      libc-ares-dev python3-dev libsystemd-dev python-ipaddress python3-sphinx \
-      install-info build-essential libsystemd-dev libsnmp-dev perl \
+      libc-ares-dev python3-dev python-ipaddress python3-sphinx \
+      install-info build-essential libsnmp-dev perl \
       libcap-dev python2 libelf-dev \
       sudo gdb curl iputils-ping time \
       libgrpc++-dev libgrpc-dev protobuf-compiler-grpc \
diff --git a/lib/libfrr.c b/lib/libfrr.c
index 0817182f7a..97dab74d9b 100644
--- a/lib/libfrr.c
+++ b/lib/libfrr.c
@@ -44,6 +44,7 @@
 #include "frr_pthread.h"
 #include "defaults.h"
 #include "frrscript.h"
+#include "systemd.h"
 
 DEFINE_HOOK(frr_late_init, (struct thread_master * tm), (tm));
 DEFINE_HOOK(frr_config_pre, (struct thread_master * tm), (tm));
@@ -363,6 +364,11 @@ void frr_preinit(struct frr_daemon_info *daemon, int argc, char **argv)
 
 		startup_fds |= UINT64_C(0x1) << (uint64_t)i;
 	}
+
+	/* note this doesn't do anything, it just grabs state, so doing it
+	 * early in _preinit is perfect.
+	 */
+	systemd_init_env();
 }
 
 bool frr_is_startup_fd(int fd)
diff --git a/lib/systemd.c b/lib/systemd.c
index c5cc3aa447..7944c2493b 100644
--- a/lib/systemd.c
+++ b/lib/systemd.c
@@ -20,68 +20,56 @@
  */
 
 #include <zebra.h>
+#include <sys/un.h>
 
 #include "thread.h"
 #include "systemd.h"
+#include "lib_errors.h"
 
-#if defined HAVE_SYSTEMD
-#include <systemd/sd-daemon.h>
-#endif
+/* these are cleared from env so they don't "leak" into things we fork(),
+ * particularly for watchfrr starting individual daemons
+ *
+ * watchdog_pid is currently not used since watchfrr starts forking.
+ * (TODO: handle that better, somehow?)
+ */
+static pid_t watchdog_pid = -1;
+static intmax_t watchdog_msec;
+
+/* not used yet, but can trigger auto-switch to journald logging */
+bool sd_stdout_is_journal;
+bool sd_stderr_is_journal;
+
+static char *notify_socket;
 
-/*
- * Wrapper this silliness if we
- * don't have systemd
+/* talk to whatever entity claims to be systemd ;)
+ *
+ * refer to sd_notify docs for messages systemd accepts over this socket.
+ * This function should be functionally equivalent to sd_notify().
  */
 static void systemd_send_information(const char *info)
 {
-#if defined HAVE_SYSTEMD
-	sd_notify(0, info);
-#else
-	return;
-#endif
-}
+	int sock;
+	struct sockaddr_un sun;
 
-/*
- * A return of 0 means that we are not watchdoged
- */
-static int systemd_get_watchdog_time(int the_process)
-{
-#if defined HAVE_SYSTEMD
-	uint64_t usec;
-	char *watchdog = NULL;
-	int ret;
-
-	ret = sd_watchdog_enabled(0, &usec);
-
-	/*
-	 * If return is 0 -> we don't want watchdog
-	 * if return is < 0, some sort of failure occurred
-	 */
-	if (ret < 0)
-		return 0;
-
-	/*
-	 * systemd can return that this process
-	 * is not the expected sender of the watchdog timer
-	 * If we set the_process = 0 then we expect to
-	 * be able to send the watchdog to systemd
-	 * irrelevant of the pid of this process.
-	 */
-	if (ret == 0 && the_process)
-		return 0;
-
-	if (ret == 0 && !the_process) {
-		watchdog = getenv("WATCHDOG_USEC");
-		if (!watchdog)
-			return 0;
-
-		usec = atol(watchdog);
-	}
+	if (!notify_socket)
+		return;
+
+	sock = socket(AF_UNIX, SOCK_DGRAM, 0);
+	if (sock < 0)
+		return;
+
+	sun.sun_family = AF_UNIX;
+	strlcpy(sun.sun_path, notify_socket, sizeof(sun.sun_path));
 
-	return (usec / 1000000) / 3;
-#else
-	return 0;
-#endif
+	/* linux abstract unix socket namespace */
+	if (sun.sun_path[0] == '@')
+		sun.sun_path[0] = '\0';
+
+	/* nothing we can do if this errors out... */
+	sendto(sock, info, strlen(info), 0, (struct sockaddr *)&sun,
+	       sizeof(sun));
+
+	close(sock);
 }
 
 void systemd_send_stopping(void)
@@ -90,34 +78,27 @@ void systemd_send_stopping(void)
 	systemd_send_information("STOPPING=1");
 }
 
-/*
- * How many seconds should we wait between watchdog sends
- */
-static int wsecs = 0;
 static struct thread_master *systemd_master = NULL;
 
 static int systemd_send_watchdog(struct thread *t)
 {
 	systemd_send_information("WATCHDOG=1");
 
-	thread_add_timer(systemd_master, systemd_send_watchdog, NULL, wsecs,
-			 NULL);
-
+	assert(watchdog_msec > 0);
+	thread_add_timer_msec(systemd_master, systemd_send_watchdog, NULL,
+			      watchdog_msec, NULL);
 	return 1;
 }
 
-void systemd_send_started(struct thread_master *m, int the_process)
+void systemd_send_started(struct thread_master *m)
 {
 	assert(m != NULL);
 
-	wsecs = systemd_get_watchdog_time(the_process);
 	systemd_master = m;
 
 	systemd_send_information("READY=1");
-	if (wsecs != 0) {
-		systemd_send_information("WATCHDOG=1");
-		thread_add_timer(m, systemd_send_watchdog, m, wsecs, NULL);
-	}
+	if (watchdog_msec > 0)
+		systemd_send_watchdog(NULL);
 }
 
 void systemd_send_status(const char *status)
@@ -127,3 +108,65 @@ void systemd_send_status(const char *status)
 	snprintf(buffer, sizeof(buffer), "STATUS=%s", status);
 	systemd_send_information(buffer);
 }
+
+static intmax_t getenv_int(const char *varname, intmax_t dflt)
+{
+	char *val, *err;
+	intmax_t intval;
+
+	val = getenv(varname);
+	if (!val)
+		return dflt;
+
+	intval = strtoimax(val, &err, 0);
+	if (*err || !*val)
+		return dflt;
+	return intval;
+}
+
+void systemd_init_env(void)
+{
+	char *tmp;
+	uintmax_t dev, ino;
+	int len;
+	struct stat st;
+
+	notify_socket = getenv("NOTIFY_SOCKET");
+
+	/* no point in setting up watchdog w/o notify socket */
+	if (notify_socket) {
+		intmax_t watchdog_usec;
+
+		watchdog_pid = getenv_int("WATCHDOG_PID", -1);
+		if (watchdog_pid <= 0)
+			watchdog_pid = -1;
+
+		/* note this is the deadline, hence the divide by 3 */
+		watchdog_usec = getenv_int("WATCHDOG_USEC", 0);
+		if (watchdog_usec >= 3000)
+			watchdog_msec = watchdog_usec / 3000;
+		else {
+			if (watchdog_usec != 0)
+				flog_err(
+					EC_LIB_UNAVAILABLE,
+					"systemd expects a %jd microsecond watchdog timer, but FRR only supports millisecond resolution!",
+					watchdog_usec);
+			watchdog_msec = 0;
+		}
+	}
+
+	tmp = getenv("JOURNAL_STREAM");
+	if (tmp && sscanf(tmp, "%ju:%ju%n", &dev, &ino, &len) == 2
+	    && (size_t)len == strlen(tmp)) {
+		if (fstat(1, &st) == 0 && st.st_dev == (dev_t)dev
+		    && st.st_ino == (ino_t)ino)
+			sd_stdout_is_journal = true;
+		if (fstat(2, &st) == 0 && st.st_dev == (dev_t)dev
+		    && st.st_ino == (ino_t)ino)
+			sd_stderr_is_journal = true;
+	}
+
+	/* these should *not* be passed to any other process we start */
+	unsetenv("WATCHDOG_PID");
+	unsetenv("WATCHDOG_USEC");
+}
diff --git a/lib/systemd.h b/lib/systemd.h
index d9885c5d9c..1933f4f688 100644
--- a/lib/systemd.h
+++ b/lib/systemd.h
@@ -28,9 +28,6 @@ extern "C" {
  *
  * Design point is that if systemd is not being used on this system
  * then these functions becomes a no-op.
- *
- * To turn on systemd compilation, use --enable-systemd on
- * configure run.
  */
 void systemd_send_stopping(void);
 
@@ -39,13 +36,18 @@ void systemd_send_stopping(void);
  *  the_process - Should we send watchdog if we are not the requested
  *                process?
  */
-void systemd_send_started(struct thread_master *master, int the_process);
+void systemd_send_started(struct thread_master *master);
 
 /*
  * status - A status string to send to systemd
  */
 void systemd_send_status(const char *status);
 
+/*
+ * grab startup state from env vars
+ */
+void systemd_init_env(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/redhat/frr.spec.in b/redhat/frr.spec.in
index e24a84d1e4..fbe4c4a1f1 100644
--- a/redhat/frr.spec.in
+++ b/redhat/frr.spec.in
@@ -199,8 +199,6 @@ Requires:       initscripts
 BuildRequires:  pam-devel
 %endif
 %if "%{initsystem}" == "systemd"
-BuildRequires:      systemd
-BuildRequires:      systemd-devel
 Requires(post):     systemd
 Requires(preun):    systemd
 Requires(postun):   systemd
@@ -396,9 +394,6 @@ routing state through standard SNMP MIBs.
     --disable-bgp-vnc \
 %endif
     --enable-isisd \
-%if "%{initsystem}" == "systemd"
-    --enable-systemd \
-%endif
     --enable-rpki \
 %if %{with_bfdd}
     --enable-bfdd \
diff --git a/watchfrr/watchfrr.c b/watchfrr/watchfrr.c
index faf1777d7f..d0b4be81d4 100644
--- a/watchfrr/watchfrr.c
+++ b/watchfrr/watchfrr.c
@@ -469,12 +469,10 @@ static int run_job(struct restart_info *restart, const char *cmdtype,
 		return -1;
 	}
 
-#if defined HAVE_SYSTEMD
 	char buffer[512];
 
 	snprintf(buffer, sizeof(buffer), "restarting %s", restart->name);
 	systemd_send_status(buffer);
-#endif
 
 	/* Note: time_elapsed test must come before the force test, since we
 	   need
@@ -506,9 +504,8 @@ static int run_job(struct restart_info *restart, const char *cmdtype,
 			restart->pid = 0;
 	}
 
-#if defined HAVE_SYSTEMD
 	systemd_send_status("FRR Operational");
-#endif
+
 	/* Calculate the new restart interval. */
 	if (update_interval) {
 		if (delay.tv_sec > 2 * gs.max_restart_interval)
@@ -718,10 +715,9 @@ static void daemon_send_ready(int exitcode)
 	fp = fopen(started, "w");
 	if (fp)
 		fclose(fp);
-#if defined HAVE_SYSTEMD
-	systemd_send_started(master, 0);
+
+	systemd_send_started(master);
 	systemd_send_status("FRR Operational");
-#endif
 	sent = 1;
 }