[PATCH 5/5] Add wayland.socket systemd unit for socket activation

[Benjamin Franzke]

Wayland compositors aiming for systemd socket activation
should use wayland.socket in Sockets= in its service files units.
This way they get automatically systemd socket activation.

The unit is installed as a user unit, so intended to be used is a
systemd user session.  This is for the reason of being able provide
general service files for compositors, e.g. not needing to set a custom
User= or Environmnet=DISPLAY=:0 or so..
In theory it could be used for a system session as well.

FIXME: The unit is installed as suggestend by systemd:man:daemon(7).
This has the drawback that if wayland is installed in a user prefix
and no custom --with-systemduserunitdir is passed to configure,
the build system tries to install to e.g. /usr/lib/systemd/user
which may be an access violation.
Maybe it should be explicitly enabled to install the unit?
---
 Makefile.am        |  3 +++
 configure.ac       |  8 ++++++++
 src/Makefile.am    |  6 +++++-
 src/wayland.socket | 15 +++++++++++++++
 4 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 src/wayland.socket

diff --git a/Makefile.am b/Makefile.am
index 306d7b3..1b6cdd7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -10,3 +10,6 @@ aclocaldir = $(datadir)/aclocal
 aclocal_DATA = wayland-scanner.m4 wayland-scanner.mk
 
 EXTRA_DIST = wayland-scanner.mk
+DISTCHECK_CONFIGURE_FLAGS = \
+	--with-systemduserunitdir=$$dc_install_base/$(systemduserunitdir)
+
diff --git a/configure.ac b/configure.ac
index 883411c..1f60ffc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -73,6 +73,14 @@ if test "x$enable_scanner" = "xyes"; then
 	AC_SUBST(EXPAT_LIBS)
 fi
 
+AC_ARG_WITH([systemduserunitdir],
+	    AS_HELP_STRING([--with-systemduserunitdir=<dir>], [Directory for systemd user service files]),
+	    [], [with_systemduserunitdir=$($PKG_CONFIG --variable=systemduserunitdir systemd)])
+if test "x$with_systemdusersystemunitdir" != xno; then
+	AC_SUBST([systemduserunitdir], [$with_systemduserunitdir])
+fi
+AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$with_systemduserunitdir" -a "x$with_systemduserunitdir" != xno ])
+
 AC_PATH_PROG(XSLTPROC, xsltproc)
 AM_CONDITIONAL([HAVE_XSLTPROC], [test "x$XSLTPROC" != "x"])
 
diff --git a/src/Makefile.am b/src/Makefile.am
index b62de56..f900cc2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -37,6 +37,10 @@ libwayland_client_la_SOURCES =			\
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = wayland-client.pc wayland-server.pc
 
+if HAVE_SYSTEMD
+systemduserunit_DATA = wayland.socket
+endif
+
 AM_CPPFLAGS = $(FFI_CFLAGS)
 AM_CFLAGS = $(GCC_CFLAGS)
 
@@ -68,4 +72,4 @@ BUILT_SOURCES =					\
 
 CLEANFILES = $(BUILT_SOURCES)
 DISTCLEANFILES = wayland-version.h
-EXTRA_DIST = wayland-version.h.in
+EXTRA_DIST = wayland-version.h.in wayland.socket
diff --git a/src/wayland.socket b/src/wayland.socket
new file mode 100644
index 0000000..b2633b3
--- /dev/null
+++ b/src/wayland.socket
@@ -0,0 +1,15 @@
+[Unit]
+Description=Wayland Socket
+
+[Socket]
+ListenStream=%t/wayland-0
+
+# The default wayland compositor should make wayland.service a
+# symlink to itself, so that this socket activates the right
+# acutal wayland compositor.
+
+# Best way to achieve that is by adding this to your unit file
+# (i.e. to weston.service):
+#
+# [Install]
+# Alias=wayland.service
-- 
1.7.12.4