Make list_active more robust

A couple of small changes to this function should make it more robust in
the long run:

1) We no longer filter the symlinks with find(1), instead combining
   filtering and substituting in sed(1)

2) We use the absolute path (as given by readlink -f) such that we can
   anchor the regular expression pattern to avoid unwanted substitution.

3) Instead of hard-coding paths we now use STOW_DIR (and STOW_DIR/.. for
   the target directory)

4) To avoid unnecessary complexity, we no longer let the user override
   STOW_DIR. This tool is supposed to be used with the canonical
   /etc/portage/stow location

1 files changed, 6 insertions, 5 deletions

diff --git a/bosun b/bosun
index 2b913b0..7d8efeb 100755
--- a/bosun
+++ b/bosun
@@ -1,7 +1,6 @@
 #!/bin/sh
 
-# allow overriding STOW_DIR by the user
-export STOW_DIR=${STOW_DIR:-/etc/portage/stow}
+export STOW_DIR=/etc/portage/stow
 
 need_root() {
 	if test "$(id -u)" -ne 0; then
@@ -46,10 +45,12 @@ list() {
 }
 
 list_active() {
+	# Note: we de not escape any special characters in $STOW_DIR since it is
+	# assumed we are in full control of its contents.
 	# XXX: -r for xargs is a GNU extension
-	find /etc/portage/ -lname "*stow/*" -print0 2>/dev/null \
-		| xargs -r0 readlink \
-		| sed 's:.*stow/\([^/]\+\)/.*:\1:' \
+	find "$STOW_DIR/.." -type l -print0 2>/dev/null \
+		| xargs -r0 readlink -f \
+		| sed -n ":^$STOW_DIR: s:^$STOW_DIR/\([^/]\+\)/.*:\1:p" \
 		| sort -u
 }