bootmisc: use find for all cleanup in tmp directories

This is for #458

conf.d/bootmisc

@@ -1,4 +1,6 @@
-# List of /tmp directories we should clean up
+# List of /tmp-like directories we should clean up.  tmpfs mounts are ignored
+# since they will be empty at boot.
+# Use of tmpfs for /tmp itself is strongly recommended if possible.
 clean_tmp_dirs="/tmp"
 
 # Should we wipe the tmp paths completely or just selectively remove known

init.d/bootmisc.in

@@ -33,11 +33,10 @@ cleanup_tmp_dir()
 	if yesno $wipe_tmp; then
 		ebegin "Wiping $dir directory"
 
-		# Faster than raw find
-		if ! rm -rf -- [!ajlq\.]* 2>/dev/null ; then
-			# Blah, too many files
-			find . -maxdepth 1 -name '[!ajlq\.]*' -exec rm -rf -- {} +
-		fi
+		# The find commands below are taken from Debian and modified to
+		# use posix syntax
+		find "${dir}" -xdev ! -type d -exec rm -- {} +
+		find "${dir}" -xdev -type d -empty -exec rmdir -- {} +
 
 		# pam_mktemp creates a .private directory within which
 		# each user gets a private directory with immutable