sh256: add back checks

kiss

@@ -141,16 +141,20 @@ sh256() {
     # All utilities must match 'sha256sum' output.
     #
     # Example: '<checksum>  <file>'
-    hash=$(
-        sha256sum               "$1" ||
-        sha256 -r               "$1" ||
-        openssl dgst -sha256 -r "$1" ||
-        shasum -a 256           "$1" ||
-        digest -a sha256        "$1"
-    ) 2>/dev/null || die "Failed to generate checksums for '$1'"
+    hash=
 
-    hash=${hash%% *}
-    printf '%s\n' "$hash"
+    if [ ! -d "$1" ] && [ -e "$1" ]; then
+        hash=$(
+            sha256sum               "$1" ||
+            sha256 -r               "$1" ||
+            openssl dgst -sha256 -r "$1" ||
+            shasum -a 256           "$1" ||
+            digest -a sha256        "$1"
+        ) 2>/dev/null || die "Failed to generate checksums for '$1'"
+
+        hash=${hash%% *}
+        printf '%s\n' "$hash"
+    fi
 }
 
 pkg_lint() {
@@ -627,7 +631,7 @@ pkg_etcsums() {
     # This can't be a simple 'find -exec' as 'sh256' is a shell function
     # and not a real command of any kind. This is the shell equivalent.
     find "$pkg_dir/$1/etc" ! -type d | sort | while read -r line; do
-        [ ! -e "$line" ] || sh256 "$line"
+        sh256 "$line"
     done > "$pkg_dir/$1/$pkg_db/$1/etcsums"
 }
 
@@ -1086,7 +1090,7 @@ pkg_remove_files() {
     while read -r file; do
         case $file in /etc/?*[!/])
             sh256 "$KISS_ROOT/$file" >/dev/null
-            sum_old=$(grep -F "$hash" "$mak_dir/c")
+            sum_old=$(grep -F "${hash:=null}" "$mak_dir/c")
 
             [ "$hash" = "$sum_old" ] || {
                 printf 'Skipping %s (modified)\n' "$file"