sh format: improve stampfile handling

- mktemp in /tmp
- don't assume $0 is a file
- remove stampfiles at exit
- don't create stampfiles if -n is passed

Closes sahib#554

lib/formats/sh.sh

@@ -41,10 +41,27 @@ DO_KEEP_DIR_TIMESTAMPS=
 # Set to true on -i
 DO_ASK_BEFORE_DELETE=
 
+# Tempfiles for saving timestamps
+STAMPFILE=
+STAMPFILE2=
+
 ##################################
 # GENERAL LINT HANDLER FUNCTIONS #
 ##################################
 
+exit_cleanup() {
+    trap - INT TERM EXIT
+    if [ -n "$STAMPFILE" ]; then
+        rm -f -- "$STAMPFILE"
+    fi
+    if [ -n "$STAMPFILE2" ]; then
+        rm -f -- "$STAMPFILE2"
+    fi
+}
+
+trap exit_cleanup EXIT
+trap exit INT TERM
+
 COL_RED='\e[0;31m'
 COL_BLUE='\e[1;34m'
 COL_GREEN='\e[0;32m'
@@ -218,12 +235,15 @@ cp_reflink() {
     printf "${COL_YELLOW}Reflinking to original: ${COL_RESET}%%s\n" "$1"
     if original_check "$1" "$2"; then
         if [ -z "$DO_DRY_RUN" ]; then
-            touch -mr "$1" -- "$0"
+            if [ -z "$STAMPFILE2" ]; then
+                STAMPFILE2=$(mktemp "${TMPDIR:-/tmp}/rmlint.XXXXXXXX.stamp")
+            fi
+            touch -mr "$1" -- "$STAMPFILE2"
             if [ -d "$1" ]; then
                 rm -rf -- "$1"
             fi
             cp --archive --reflink=always -- "$2" "$1"
-            touch -mr "$0" -- "$1"
+            touch -mr "$STAMPFILE2" -- "$1"
         fi
     fi
 }
@@ -278,7 +298,6 @@ remove_cmd() {
             if [ -n "$DO_KEEP_DIR_TIMESTAMPS" ]; then
                 # Swap back old directory timestamp:
                 touch -r "$STAMPFILE" -- "$(dirname "$1")"
-                rm -- "$STAMPFILE"
             fi
 
             if [ -n "$DO_DELETE_EMPTY_DIRS" ]; then
@@ -380,7 +399,6 @@ do
        ;;
      k)
        DO_KEEP_DIR_TIMESTAMPS=true
-       STAMPFILE=$(mktemp 'rmlint.XXXXXXXX.stamp')
        ;;
      i)
        DO_ASK_BEFORE_DELETE=true
@@ -402,11 +420,12 @@ then
   ask
 fi
 
-if [ -n "$DO_DRY_RUN" ]
-then
+if [ -n "$DO_DRY_RUN" ]; then
     printf "#${COL_YELLOW} ////////////////////////////////////////////////////////////${COL_RESET}\n"
     printf "#${COL_YELLOW} /// ${COL_RESET} This is only a dry run; nothing will be modified! ${COL_YELLOW}///${COL_RESET}\n"
     printf "#${COL_YELLOW} ////////////////////////////////////////////////////////////${COL_RESET}\n"
+elif [ -n "$DO_KEEP_DIR_TIMESTAMPS" ]; then
+    STAMPFILE=$(mktemp "${TMPDIR:-/tmp}/rmlint.XXXXXXXX.stamp")
 fi
 
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