Merge pull request #4074 from jfinkels/cp-force-dangling-symlink

cp: restrict copy through dangling symlink with -f

src/uu/cp/src/cp.rs

@@ -1270,10 +1270,6 @@ fn copy_file(
         return Ok(());
     }
 
-    if file_or_link_exists(dest) {
-        handle_existing_dest(source, dest, options, source_in_command_line)?;
-    }
-
     // Fail if dest is a dangling symlink or a symlink this program created previously
     if dest.is_symlink() {
         if FileInformation::from_path(dest, false)
@@ -1287,7 +1283,13 @@ fn copy_file(
             )));
         }
         let copy_contents = options.dereference(source_in_command_line) || !source.is_symlink();
-        if copy_contents && !dest.exists() {
+        if copy_contents
+            && !dest.exists()
+            && !matches!(
+                options.overwrite,
+                OverwriteMode::Clobber(ClobberMode::RemoveDestination)
+            )
+        {
             return Err(Error::Error(format!(
                 "not writing through dangling symlink '{}'",
                 dest.display()
@@ -1295,6 +1297,10 @@ fn copy_file(
         }
     }
 
+    if file_or_link_exists(dest) {
+        handle_existing_dest(source, dest, options, source_in_command_line)?;
+    }
+
     if options.verbose {
         println!("{}", context_for(source, dest));
     }

tests/by-util/test_cp.rs

@@ -1839,6 +1839,19 @@ fn test_copy_through_dangling_symlink_no_dereference_2() {
         .stderr_only("cp: not writing through dangling symlink 'target'");
 }
 
+/// Test that copy through a dangling symbolic link fails, even with --force.
+#[test]
+#[cfg(not(windows))]
+fn test_copy_through_dangling_symlink_force() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.touch("src");
+    at.symlink_file("no-such-file", "dest");
+    ucmd.args(&["--force", "src", "dest"])
+        .fails()
+        .stderr_only("cp: not writing through dangling symlink 'dest'");
+    assert!(!at.file_exists("dest"));
+}
+
 #[test]
 #[cfg(unix)]
 fn test_cp_archive_on_nonexistent_file() {