Recover legacy code for systems using util-linux < 2.22

tomb

@@ -305,10 +305,44 @@ _ensure_safe_swap() {
     [[ -z "$swaps" ]] && return 0 # No swap partition is active
 
     _message "An active swap partition is detected..."
-    for s in $=swaps; do
-        { _is_encrypted_block $s } \
-	    && { r=2 } || { r=1; break }
-    done
+
+    # Issue #163
+    # lsblk --inverse appeared in util-linux 2.22
+    # but --version is not consistent...
+    local bug_163=0
+    lsblk --help | grep -q '\-\-inverse'
+    if [[ $? -eq 0 ]]; then
+	for s in $=swaps; do
+            { _is_encrypted_block $s } \
+		&& { r=2 } || { r=1; break }
+	done
+    else
+	# Use legacy code that does not detect plain swaps on
+	# encrypted volumes.  On such systems -f must be used.
+	bug_163=1
+	for s in $=swaps; do
+	    bone=$(sudo file $s)
+	    if [[ "$bone" =~ "swap file" ]]; then
+		# It's a regular (unencrypted) swap file
+		r=1
+		break
+
+	    elif [[ "$bone" =~ "symbolic link" ]]; then
+		# Might link to a block
+		r=1
+		[[ "/dev/mapper" == "${s%/*}" ]] || { break }
+		is_crypt=$(sudo dmsetup status "$s" | awk '/crypt/ {print $3}')
+		[[ $is_crypt == "crypt" ]] && { r=2 }
+
+	    elif [[ "$bone" =~ "block special" ]]; then
+		# It's a block
+		r=1
+		is_crypt=`sudo dmsetup status "$s" | awk '/crypt/ {print $3}'`
+		[[ $is_crypt == "crypt" ]] && { r=2 } || { break }
+
+	    fi
+	done
+    fi
 
     if [[ $r -eq 2 ]]; then
         _success "All your swaps are belong to crypt.  Good."
@@ -317,6 +351,10 @@ _ensure_safe_swap() {
         _warning "You can deactivate all swap partitions using the command:"
         _warning " swapoff -a"
         _warning "But if you want to proceed like this, use the -f (force) flag."
+	if [[ $bug_163 -eq 1 ]]; then
+	    _warning "[#163] I cannot detect plain swaps on an encrypted volume."
+	    _warning "[#163] Use -f, or upgrade util-linux to 2.22+."
+	fi
     fi
     return $r