chmod: report the real error for files below the -R operand

src/uu/chmod/src/chmod.rs

@@ -837,20 +837,8 @@ impl Chmoder {
 
         // Use safe traversal to change the mode
         if let Err(e) = dir_fd.chmod_at(entry_name, new_mode, symlink_behavior) {
-            if self.verbose {
-                println!(
-                    "failed to change mode of {} to {new_mode:o}",
-                    file_path.quote(),
-                );
-            }
-
-            return Err(match e.kind() {
-                std::io::ErrorKind::ReadOnlyFilesystem => {
-                    ChmodError::ChangingPermissions(file_path.into(), e)
-                }
-                _ => ChmodError::PermissionDenied(file_path.into()),
-            }
-            .into());
+            self.report_failed_change(file_path, e, current_mode, new_mode);
+            return Ok(());
         }
 
         // Report the change using the helper method
@@ -903,32 +891,39 @@ impl Chmoder {
             return Ok(());
         }
 
-        self.change_file(fperm, self.fmode.unwrap_or(new_mode), file)?;
-
-        self.report_umask_conflict(file, new_mode, naively_expected_new_mode);
+        if self.change_file(fperm, self.fmode.unwrap_or(new_mode), file) {
+            self.report_umask_conflict(file, new_mode, naively_expected_new_mode);
+        }
 
         Ok(())
     }
 
-    fn change_file(&self, fperm: u32, mode: u32, file: &Path) -> UResult<()> {
+    /// Returns false if the mode could not be changed (already reported).
+    fn change_file(&self, fperm: u32, mode: u32, file: &Path) -> bool {
         // Always issue the chmod(2) call, even when the bits are unchanged: the
         // syscall can still fail (e.g. lacking permission on the file) and that
         // failure must be reported, matching GNU.
         if let Err(err) = fs::set_permissions(file, fs::Permissions::from_mode(mode)) {
-            if self.verbose {
-                println!(
-                    "failed to change mode of file {} from {fperm:04o} ({}) to {mode:04o} ({})",
-                    file.quote(),
-                    display_permissions_unix(fperm, false),
-                    display_permissions_unix(mode, false)
-                );
-            }
-            return Err(ChmodError::ChangingPermissions(file.into(), err).into());
+            self.report_failed_change(file, err, fperm, mode);
+            return false;
         }
 
         // Use the helper method for consistent reporting
         self.report_permission_change(file, fperm, mode);
-        Ok(())
+        true
+    }
+
+    /// Report a failed chmod: the error first, then the `-v` line, like GNU.
+    fn report_failed_change(&self, file: &Path, err: std::io::Error, old_mode: u32, new_mode: u32) {
+        self.report_failure(ChmodError::ChangingPermissions(file.into(), err).into());
+        if self.verbose {
+            println!(
+                "failed to change mode of {} from {old_mode:04o} ({}) to {new_mode:04o} ({})",
+                file.quote(),
+                display_permissions_unix(old_mode, false),
+                display_permissions_unix(new_mode, false)
+            );
+        }
     }
 }
 

tests/by-util/test_chmod.rs

@@ -596,6 +596,36 @@ fn test_chmod_readonly_filesystem() {
     scene.umount_temp_fs();
 }
 
+#[test]
+fn test_chmod_recursive_reports_real_error_below_operand() {
+    use rustix::process::geteuid;
+
+    // '-L' makes chmod follow the link to a root-owned file: EPERM
+    let target = "/etc/passwd";
+    let Ok(meta) = metadata(target) else { return };
+    if geteuid().is_root() || meta.uid() != 0 {
+        return;
+    }
+    let mode = meta.mode() & 0o7777;
+
+    let ts = TestScenario::new(util_name!());
+    ts.fixtures.mkdir("tree");
+    ts.fixtures.symlink_file(target, "tree/link");
+
+    ts.ucmd()
+        .args(&["-R", "-L", "u+r", "tree"])
+        .fails_with_code(1)
+        .stderr_is("chmod: changing permissions of 'tree/link': Operation not permitted\n");
+
+    ts.ucmd()
+        .args(&["-v", "-R", "-L", "u+r", "tree"])
+        .fails_with_code(1)
+        .stdout_contains(format!(
+            "failed to change mode of 'tree/link' from {mode:04o} ("
+        ))
+        .stdout_contains(format!(") to {:04o} (", mode | 0o400));
+}
+
 #[test]
 #[allow(clippy::unreadable_literal)]
 fn test_chmod_recursive_correct_exit_code() {
@@ -1898,7 +1928,7 @@ fn test_chmod_reports_every_failing_operand() {
         .args(&["-v", "-f", "0", "/", "/"])
         .fails_with_code(1)
         .no_stderr()
-        .stdout_contains("failed to change mode of file '/' from");
+        .stdout_contains("failed to change mode of '/' from");
 }
 
 #[test]