functions: refactor get_{base,dir}name

Make sure these are completely safe for user input. Use the same three
step process in both cases:

1) Strip any trailing slash
2) Trim the string according to base/dir request
3) Print the result, defaulting to / if step 2 yielded an empty string

Signed-off-by: Dave Reisner <d@falconindy.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/functions b/functions
index c7e167e..2f5797a 100644
--- a/functions
+++ b/functions
@@ -30,15 +30,16 @@ die() {
     cleanup 1
 }
 
-get_dirname() {
-    # strip any trailing slash first...
-    local dir="${1%/}"
-    # then get the directory portion
-    echo "${dir%/*}"
+get_basename() {
+  local base=${1%/}
+  base=${base##*/}
+  printf '%s' "${base:-/}"
 }
 
-get_basename() {
-    echo "${1##*/}"
+get_dirname() {
+  local dir=${1%/}
+  dir=${dir%/*}
+  printf '%s' "${dir:-/}"
 }
 
 in_array() {