libsystemd: new library, refactor sd-daemon.[ch] test code

This commit introduces a bare-bones replacement for libsystemd:

 - Build .so file and add --with-libsystemd to configure
 - Add capabilities support to test/src/serv.c
 - Update tests to account for a Finit built w/o libsystemd support

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

Makefile.am

@@ -1,5 +1,5 @@
 ACLOCAL_AMFLAGS    = -I m4
-SUBDIRS            = man plugins src system test tmpfiles.d
+SUBDIRS            = man plugins src system tmpfiles.d
 doc_DATA           = README.md LICENSE contrib/finit.conf
 EXTRA_DIST         = README.md LICENSE ChangeLog.md contrib/finit.conf
 
@@ -9,6 +9,17 @@ endif
 if DOC
 SUBDIRS           += doc
 endif
+if LIBSYSTEMD
+SUBDIRS           += libsystemd
+endif
+
+if LIBSYSTEMD
+SUBDIRS           += test
+# Explicit dependency to ensure libsystemd is built before test
+test: libsystemd
+else
+SUBDIRS           += test
+endif
 
 if BASH
 bashdir            = $(BASH_DIR)

configure.ac

@@ -12,6 +12,7 @@ AC_CONFIG_FILES([Makefile
 	contrib/debian/Makefile contrib/debian/finit.d/Makefile contrib/debian/finit.d/available/Makefile
 	contrib/void/Makefile   contrib/void/finit.d/Makefile   contrib/void/finit.d/available/Makefile
 	doc/Makefile
+	libsystemd/Makefile libsystemd/libsystemd.pc
 	man/Makefile
 	plugins/Makefile
 	src/Makefile
@@ -168,6 +169,10 @@ AC_ARG_WITH(watchdog,
         AS_HELP_STRING([--with-watchdog@<:@=DEV@:>@], [Enable built-in watchdog, default: /dev/watchdog]),
 	[watchdog=$withval], [with_watchdog=no watchdog=])
 
+AC_ARG_WITH(libsystemd,
+        AS_HELP_STRING([--with-libsystemd], [Build replacement libsystemd library, default: yes]),
+	[with_libsystemd=$withval], [with_libsystemd=yes])
+
 AC_ARG_WITH(hook-scripts-path,
         AS_HELP_STRING([--with-hook-scripts-path=DIR], [Base directory for hook scripts, default $libexecdir/finit/hook]),
 	[hook_scripts_path=$withval], [hook_scripts_path=yes])
@@ -308,6 +313,9 @@ AS_IF([test "x$with_watchdog" != "xno"], [
         AC_DEFINE_UNQUOTED(WDT_DEVNODE, "$watchdog", [Built-in watchdog device node])], [
 	watchdog=])
 
+AS_IF([test "x$with_libsystemd" != "xno"], [
+        AC_DEFINE(HAVE_LIBSYSTEMD, 1, [Build replacement libsystemd library support])])
+
 AS_IF([test "x$enable_hook_scripts_plugin" != "xno"], [
 	AS_IF([test "x$hook_scripts_path" = "xyes"], [hook_scripts_path=$libexecdir/finit/hook])
 	AC_EXPAND_DIR(hook_scripts_path, "$hook_scripts_path")
@@ -319,14 +327,15 @@ AS_IF([test "x$with_plugin_path" != "xno"], [
 	AC_DEFINE_UNQUOTED(EXTERNAL_PLUGIN_PATH, "$plugin_path", [Built-in default: /usr/lib/finit/plugins:/usr/local/lib/finit/plugins])])
 
 # Control build with automake flags
-AM_CONDITIONAL(BASH,      [test "x$bash_dir"      != "xno"])
-AM_CONDITIONAL(STATIC,    [test "x$enable_static"  = "xyes"])
-AM_CONDITIONAL(KEVENTD,   [test "x$with_keventd"  != "xno"])
-AM_CONDITIONAL(SULOGIN,   [test "x$with_sulogin"  != "xno"])
-AM_CONDITIONAL(WATCHDOGD, [test "x$with_watchdog" != "xno"])
-AM_CONDITIONAL(DOC,       [test "x$enable_doc"     = "xyes"])
-AM_CONDITIONAL(CONTRIB,   [test "x$enable_contrib" = "xyes"])
-AM_CONDITIONAL(TESTSERV,  [test "x$enable_testserv_plugin" = "xyes"])
+AM_CONDITIONAL(BASH,        [test "x$bash_dir"        != "xno"])
+AM_CONDITIONAL(STATIC,      [test "x$enable_static"    = "xyes"])
+AM_CONDITIONAL(KEVENTD,     [test "x$with_keventd"    != "xno"])
+AM_CONDITIONAL(SULOGIN,     [test "x$with_sulogin"    != "xno"])
+AM_CONDITIONAL(WATCHDOGD,   [test "x$with_watchdog"   != "xno"])
+AM_CONDITIONAL(LIBSYSTEMD,  [test "x$with_libsystemd" != "xno"])
+AM_CONDITIONAL(DOC,         [test "x$enable_doc"       = "xyes"])
+AM_CONDITIONAL(CONTRIB,     [test "x$enable_contrib"   = "xyes"])
+AM_CONDITIONAL(TESTSERV,    [test "x$enable_testserv_plugin" = "xyes"])
 
 # Workaround for as-of-yet unreleased runstatedir support, planned for
 # autoconf 2.70, which some major distros have backported.
@@ -408,6 +417,7 @@ Optional features:
   Built-in sulogin......: $with_sulogin $sulogin
   Built-in watchdogd....: $with_watchdog $watchdog
   Built-in logrotate....: $enable_logrotate
+  Replacement libsystemd: $with_libsystemd
   Use cgroup v2.........: $enable_cgroup
   Parse kernel cmdline..: $enable_kernel_cmdline
   Keep kernel logging...: $enable_kernel_logging

libsystemd/.gitignore

@@ -0,0 +1,7 @@
+.deps/*
+.libs/*
+.dirstamp
+*.lo
+libsystemd.*
+Makefile
+Makefile.in

libsystemd/Makefile.am

@@ -0,0 +1,12 @@
+# libsystemd replacement library
+lib_LTLIBRARIES          = libsystemd.la
+libsystemd_la_SOURCES    = sd-daemon.c sd-daemon.h
+libsystemd_la_LDFLAGS    = -version-info 0:0:0
+
+# pkg-config support
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libsystemd.pc
+
+# Install header to systemd/ subdirectory
+systemddir = $(includedir)/systemd
+systemd_HEADERS = sd-daemon.h

libsystemd/libsystemd.pc.in

@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: libsystemd
+Description: Finit replacement for systemd notification library
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lsystemd
+Cflags: -I${includedir}

src/Makefile.am

@@ -9,6 +9,7 @@ endif
 
 sbin_PROGRAMS        = finit initctl
 pkglibexec_PROGRAMS  = getty logit runparts tmpfiles
+
 if SULOGIN
 pkglibexec_PROGRAMS += sulogin
 endif

test/notify.sh

@@ -25,6 +25,15 @@ test_one()
     type=$1
     service=$2
 
+    # Skip systemd tests if serv doesn't have libsystemd support
+    if [ "$type" = "systemd" ]; then
+        if ! "$TEST_DIR/src/serv" -C | grep -q "libsystemd"; then
+	    sep
+            say "Skipping systemd test - serv built without libsystemd support"
+            return 0
+        fi
+    fi
+
     sep
 
 #    num=$(run "find /proc/1/fd |wc -l")

test/src/.gitignore

@@ -1,5 +1,5 @@
 /Makefile
 /Makefile.in
-
+/.libs/
 /.deps/
 /serv

test/src/Makefile.am

@@ -1,4 +1,8 @@
 noinst_PROGRAMS = serv
 
-serv_SOURCES    = serv.c sd-daemon.c sd-daemon.h
-serv_CPPFLAGS   = -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -D_GNU_SOURCE -D_DEFAULT_SOURCE
+serv_SOURCES    = serv.c
+serv_CPPFLAGS   = -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -D_GNU_SOURCE -D_DEFAULT_SOURCE -I$(top_builddir)
+if LIBSYSTEMD
+serv_CPPFLAGS  += -I$(top_srcdir)/libsystemd
+serv_SOURCES   += $(top_srcdir)/libsystemd/sd-daemon.c
+endif

test/src/serv.c

@@ -5,6 +5,10 @@
  * in foregrund it does not create a PID file by default.
  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include <errno.h>
 #include <fcntl.h>
 #include <paths.h>
@@ -16,7 +20,9 @@
 #include <sysexits.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#ifdef HAVE_LIBSYSTEMD
 #include "sd-daemon.h"
+#endif
 
 #define PROGNM "serv"
 
@@ -146,6 +152,16 @@ static void pidfile(char *pidfn)
 	}
 }
 
+static int capabilities(void)
+{
+#ifdef HAVE_LIBSYSTEMD
+	puts("libsystemd");
+#endif
+	puts("s6");
+
+	return 0;
+}
+
 static int usage(int rc)
 {
 	FILE *fp = rc ? stderr : stdout;
@@ -153,6 +169,7 @@ static int usage(int rc)
 	fprintf(fp,
 		"%s [-nhp] [-P FILE]\n"
 		"\n"
+		" -C       Show capabilities and exit\n"
 		" -c       Crash (exit) immediately\n"
 		" -e K:V   Verify K environment variable is V value\n"
 		" -E K     Verify K is not set in the environment\n"
@@ -195,11 +212,13 @@ int main(int argc, char *argv[])
 	char cmd[80];
 	int c;
 
-	while ((c = getopt(argc, argv, "ce:E:f:F:hi:nN:pP:r:")) != EOF) {
+	while ((c = getopt(argc, argv, "cCe:E:f:F:hi:nN:pP:r:")) != EOF) {
 		switch (c) {
 		case 'c':
 			do_crash = 1;
 			break;
+		case 'C':
+			return capabilities();
 		case 'e':
 			verify_env(optarg);
 			break;
@@ -295,11 +314,15 @@ int main(int argc, char *argv[])
 						err(1, "Failed closing notify socket");
 					do_notify = 0;
 				} else {
+#ifdef HAVE_LIBSYSTEMD
 					int rc;
 
 					inf("Notifying Finit on NOTIFY_SOCKET");
 					rc = sd_notify(0, "READY=1");
 					inf("sd_notify () => %d", rc);
+#else
+					inf("Skipping systemd notify - built without libsystemd support");
+#endif
 				}
 			}
 			if (do_pidfile > 0)