Allow running on non modern root filesystems

All modern Linux systems have the ephemeral local state directory
created at "/run" - however this is not universal even across just the
supported Linux systems.

Add a configure option to set the location of run dir that is compiled
into the binary.

(See PR n42n#48 and n42n#49)

Makefile

@@ -62,13 +62,14 @@ INSTALL_DOC=$(INSTALL) -m444
 # DESTDIR set in debian make system
 PREFIX=$(DESTDIR)/$(CONFIG_PREFIX)
 
-# Note that both these install dirs are outside of the CONFIG_PREFIX.
+# Note that these three install dirs are outside of the CONFIG_PREFIX.
 # The ETCDIR is not configurable in the code, so no changes should be done
 # without code changes.
 # The systemd unit dir should default to /lib for most Debian packages (if
 # CONFIG_PREFIX is /usr) otherwise it should be based on the prefix.
 # The current autotools has hacks to apply this logic.
 ETCDIR=$(DESTDIR)/etc/n3n
+CONFIG_RUNDIR?=$(DESTDIR)/run
 CONFIG_SYSTEMDDIR?=$(DESTDIR)/lib/systemd/system
 
 CONFIG_BINDIR?=$(PREFIX)/bin
@@ -78,6 +79,8 @@ MAN7DIR=$(CONFIG_MANDIR)/man7
 MAN8DIR=$(CONFIG_MANDIR)/man8
 CONFIG_DOCDIR?=$(PREFIX)/share/doc/n3n
 
+CFLAGS+=-DCONFIG_RUNDIR='"$(CONFIG_RUNDIR)"'
+
 #######################################
 # All the additiona needed for using the n3n library
 #

config.mak.in

@@ -7,9 +7,10 @@ CONFIG_HOST=@host@
 CONFIG_HOST_OS=@host_os@
 
 CONFIG_PREFIX=@CONFIG_PREFIX@
-CONFIG_DOCDIR=$(DESTDIR)/@CONFIG_DOCDIR@
-CONFIG_MANDIR=$(DESTDIR)/@CONFIG_MANDIR@
-CONFIG_SYSTEMDDIR=$(DESTDIR)/@CONFIG_SYSTEMDDIR@
+CONFIG_DOCDIR=$(DESTDIR)@CONFIG_DOCDIR@
+CONFIG_MANDIR=$(DESTDIR)@CONFIG_MANDIR@
+CONFIG_RUNDIR=$(DESTDIR)@CONFIG_RUNDIR@
+CONFIG_SYSTEMDDIR=$(DESTDIR)@CONFIG_SYSTEMDDIR@
 
 CONFIG_WITH_OPENSSL=@with_openssl@
 

configure.ac

@@ -120,6 +120,10 @@ AS_IF([test "x$prefix" = "xNONE" ],
     prefix=/usr/local
 )
 
+AS_IF([test "x$runstatedir" = 'x${localstatedir}/run' ],
+    runstatedir=/run
+)
+
 # The systemd unit dir should be in a sane location (based on the prefix) but
 # that is not always a dir underneath the prefix.  Apply another hack
 AS_IF([test "x$systemddir" = "x" ],
@@ -134,13 +138,15 @@ AS_IF([test "x$systemddir" = "x" ],
 CONFIG_DOCDIR=$(eval echo $(eval echo $docdir))
 CONFIG_MANDIR=$(eval echo $(eval echo $mandir))
 CONFIG_PREFIX=$prefix
+CONFIG_RUNDIR=$runstatedir
 CONFIG_SYSTEMDDIR=$systemddir
 
 configure_command=$0$ac_configure_args_raw
 
 AC_SUBST(CONFIG_DOCDIR)
 AC_SUBST(CONFIG_MANDIR)
 AC_SUBST(CONFIG_PREFIX)
+AC_SUBST(CONFIG_RUNDIR)
 AC_SUBST(CONFIG_SYSTEMDDIR)
 
 AC_SUBST(configure_command)

src/conffile.c

@@ -1383,7 +1383,7 @@ int n3n_config_setup_sessiondir (n2n_edge_conf_t *conf) {
 
 
 #ifndef _WIN32
-    char *basedir = "/run/n3n";
+    char *basedir = CONFIG_RUNDIR "/n3n";
 #endif
 #ifdef _WIN32
     char basedir[1024];