Handle systems with new /run tmpfs

Modern systems today use a RAM disk for /run and /run/lock, with
symlinks to the FHS locations in /var/run and /var/lock.  See the
following link for details http://lwn.net/Articles/436012/

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

TODO.md

@@ -140,13 +140,6 @@ Documentation
   how close Finit3 still is to the original easy-to-use Finit0 :)
 
 
-Investigation
--------------
-
-* [FHS changes](http://askubuntu.com/questions/57297/why-has-var-run-been-migrated-to-run)
-  affecting runtime status, plugins, etc.
-
-
 [libwdt]:                http://www.wehavemorefun.de/fritzbox/Libwdt.so
 [Fritz!Box source dump]: ftp://ftp.avm.de/fritz.box/fritzbox.fon_wlan_7170/x_misc/opensrc/
 

finit.c

@@ -27,6 +27,7 @@
 #include <sys/mount.h>
 #include <ctype.h>
 #include <dirent.h>
+#include <mntent.h>
 #include <sys/stat.h>		/* umask(), mkdir() */
 #include <lite/lite.h>
 
@@ -69,6 +70,28 @@ static int banner(void)
 	return 0;
 }
 
+/* Requires /proc to be mounted */
+static int fismnt(char *dir)
+{
+	FILE *fp;
+	int found = 0;
+	struct mntent *mnt;
+
+	fp = setmntent("/proc/mounts", "r");
+	if (!fp)
+		return 0;	/* Dunno, maybe not */
+
+	while ((mnt = getmntent(fp))) {
+		if (!strcmp(mnt->mnt_dir, dir)) {
+			found = 1;
+			break;
+		}
+	}
+	endmntent(fp);
+
+	return found;
+}
+
 int main(int argc, char* argv[])
 {
 	int err;
@@ -100,10 +123,21 @@ int main(int argc, char* argv[])
 	mount("none", "/proc", "proc", 0, NULL);
 	mount("none", "/proc/bus/usb", "usbfs", 0, NULL);
 	mount("none", "/sys", "sysfs", 0, NULL);
+
+	/* Some systems use /dev/pts */
 	makedir("/dev/pts", 0755);
+	mount("devpts", "/dev/pts", "devpts", 0, "gid=5,mode=620");
+
 	makedir("/dev/shm", 0755);
-	mount("none", "/dev/pts", "devpts", 0, "gid=5,mode=620");
-	mount("none", "/dev/shm", "tmpfs", 0, NULL);
+	if (!fismnt("/dev/shm"))
+		mount("shm", "/dev/shm", "tmpfs", 0, NULL);
+
+	/*
+	 * New tmpfs based /run for volatile runtime data
+	 * For details, see http://lwn.net/Articles/436012/
+	 */
+	if (fisdir("/run") && !fismnt("/run"))
+		mount("tmpfs", "/run", "tmpfs", MS_NODEV, "mode=0755,size=10%");
 	umask(022);
 
 	/*

plugins/bootmisc.c

@@ -44,12 +44,20 @@ static void setup(void *UNUSED(arg))
 	makedir("/var/lib/misc",   0755);
 	makedir("/var/lib/alarm",  0755);
 	makedir("/var/lib/urandom",0755);
-	makedir("/var/lock",       0755);
+	if (fisdir("/run")) {
+		_d("System with new /run tmpfs ...");
+		makedir("/run/lock",       1777);
+		symlink("/run/lock", "/var/lock");
+		symlink("/run",      "/var/run");
+		symlink("/dev/shm",  "/run/shm");
+	} else {
+		makedir("/var/lock",       1777);
+		makedir("/var/run",        0755);
+	}
 	makedir("/var/lock/subsys",0755); /* Needed by D-Bus plugin */
 	makedir("/var/log",        0755);
 	makedir("/var/mail",       0755);
 	makedir("/var/opt",        0755);
-	makedir("/var/run",        0755);
 	makedir("/var/spool",      0755);
 	makedir("/var/spool/cron", 0755);
 	makedir("/var/tmp",        0755);