tail: Handle missing/dir paths via metadata()

src/uu/tail/src/tail.rs

@@ -118,85 +118,108 @@ fn tail_file(
     observer: &mut Observer,
     offset: u64,
 ) -> UResult<()> {
-    if !path.exists() {
-        set_exit_code(1);
-        show_error!(
-            "{}",
-            translate!("tail-error-cannot-open-no-such-file", "file" => input.display_name.clone(), "error" => translate!("tail-no-such-file-or-directory"))
-        );
-        observer.add_bad_path(path, input.display_name.as_str(), false)?;
-    } else if path.is_dir() {
-        set_exit_code(1);
-
-        header_printer.print_input(input);
-        let err_msg = translate!("tail-is-a-directory");
-
-        show_error!(
-            "{}",
-            translate!("tail-error-reading-file", "file" => input.display_name.clone(), "error" => err_msg)
-        );
-        if settings.follow.is_some() {
-            let msg = if settings.retry {
-                ""
-            } else {
-                &translate!("tail-giving-up-on-this-name")
-            };
+    match path.metadata() {
+        Ok(md) if md.is_dir() => {
+            set_exit_code(1);
+
+            header_printer.print_input(input);
+            let err_msg = translate!("tail-is-a-directory");
+
             show_error!(
                 "{}",
-                translate!("tail-error-cannot-follow-file-type", "file" => input.display_name.clone(), "msg" => msg)
+                translate!(
+                    "tail-error-reading-file",
+                    "file" => input.display_name.clone(),
+                    "error" => err_msg
+                )
             );
+            if settings.follow.is_some() {
+                let msg = if settings.retry {
+                    ""
+                } else {
+                    &translate!("tail-giving-up-on-this-name")
+                };
+                show_error!(
+                    "{}",
+                    translate!(
+                        "tail-error-cannot-follow-file-type",
+                        "file" => input.display_name.clone(),
+                        "msg" => msg
+                    )
+                );
+            }
+            if !observer.follow_name_retry() {
+                return Ok(());
+            }
+            observer.add_bad_path(path, input.display_name.as_str(), false)?;
+            return Ok(());
         }
-        if !observer.follow_name_retry() {
-            // skip directory if not retry
+        Err(e) if e.kind() == ErrorKind::NotFound => {
+            set_exit_code(1);
+            show_error!(
+                "{}",
+                translate!(
+                    "tail-error-cannot-open-no-such-file",
+                    "file" => input.display_name.clone(),
+                    "error" => translate!("tail-no-such-file-or-directory")
+                )
+            );
+            observer.add_bad_path(path, input.display_name.as_str(), false)?;
             return Ok(());
         }
-        observer.add_bad_path(path, input.display_name.as_str(), false)?;
-    } else {
-        #[cfg(unix)]
-        let open_result = open_file(path, settings.pid != 0);
-        #[cfg(not(unix))]
-        let open_result = File::open(path);
-
-        match open_result {
-            Ok(mut file) => {
-                let st = file.metadata()?;
-                let blksize_limit = uucore::fs::sane_blksize::sane_blksize_from_metadata(&st);
-                header_printer.print_input(input);
-                let mut reader;
-                if !settings.presume_input_pipe
-                    && file.is_seekable(if input.is_stdin() { offset } else { 0 })
-                    && (!st.is_file() || st.len() > blksize_limit)
-                {
-                    bounded_tail(&mut file, settings);
-                    reader = BufReader::new(file);
-                } else {
-                    reader = BufReader::new(file);
-                    unbounded_tail(&mut reader, settings)?;
-                }
-                if input.is_tailable() {
-                    observer.add_path(
-                        path,
-                        input.display_name.as_str(),
-                        Some(Box::new(reader)),
-                        true,
-                    )?;
-                } else {
-                    observer.add_bad_path(path, input.display_name.as_str(), false)?;
-                }
-            }
-            Err(e) if e.kind() == ErrorKind::PermissionDenied => {
-                observer.add_bad_path(path, input.display_name.as_str(), false)?;
-                show!(e.map_err_context(|| {
-                    translate!("tail-error-cannot-open-for-reading", "file" => input.display_name.clone())
-                }));
+        _ => {}
+    }
+
+    #[cfg(unix)]
+    let open_result = open_file(path, settings.pid != 0);
+    #[cfg(not(unix))]
+    let open_result = File::open(path);
+
+    match open_result {
+        Ok(mut file) => {
+            let st = file.metadata()?;
+            let blksize_limit = uucore::fs::sane_blksize::sane_blksize_from_metadata(&st);
+            header_printer.print_input(input);
+            let mut reader;
+            if !settings.presume_input_pipe
+                && file.is_seekable(if input.is_stdin() { offset } else { 0 })
+                && (!st.is_file() || st.len() > blksize_limit)
+            {
+                bounded_tail(&mut file, settings);
+                reader = BufReader::new(file);
+            } else {
+                reader = BufReader::new(file);
+                unbounded_tail(&mut reader, settings)?;
             }
-            Err(e) => {
+            if input.is_tailable() {
+                observer.add_path(
+                    path,
+                    input.display_name.as_str(),
+                    Some(Box::new(reader)),
+                    true,
+                )?;
+            } else {
                 observer.add_bad_path(path, input.display_name.as_str(), false)?;
-                return Err(e.map_err_context(|| {
-                    translate!("tail-error-cannot-open-for-reading", "file" => input.display_name.clone())
-                }));
             }
         }
+        Err(e) if e.kind() == ErrorKind::PermissionDenied => {
+            observer.add_bad_path(path, input.display_name.as_str(), false)?;
+            show!(e.map_err_context(|| {
+                translate!(
+                    "tail-error-cannot-open-for-reading",
+                    "file" => input.display_name.clone()
+                )
+            }));
+        }
+        Err(e) => {
+            observer.add_bad_path(path, input.display_name.as_str(), false)?;
+            return Err(e.map_err_context(|| {
+                translate!(
+                    "tail-error-cannot-open-for-reading",
+                    "file" => input.display_name.clone()
+                )
+            }));
+        }
     }
 
     Ok(())

tests/by-util/test_tail.rs

@@ -274,6 +274,58 @@
         .stdout_is("==> file1 <==\n\n==> file2 <==\n");
 }
 
+
+// TODO: Add similar test for windows
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_permission_denied_from_metadata_error() {
+    use std::fs;
+    use std::os::unix::fs::PermissionsExt;
+
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("noaccess");
+    at.write("noaccess/secret", "topsecret\n");
+
+    // Make the directory non-searchable so path lookup fails with EACCES.
+    fs::set_permissions(at.plus("noaccess"), fs::Permissions::from_mode(0o000)).unwrap();
+
+    ts.ucmd()
+        .arg("noaccess/secret")
+        .fails_with_code(1)
+        .no_stdout()
+        .stderr_is("tail: cannot open 'noaccess/secret' for reading: Permission denied\n");
+
+    // Restore permissions so the test harness can clean up the temp directory.
+    fs::set_permissions(at.plus("noaccess"), fs::Permissions::from_mode(0o700)).unwrap();
+}
+
+// Same as above, but ensure we keep processing subsequent files.
+// TODO: Add similar test for windows
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_permission_denied_from_metadata_error_multiple() {
+    use std::fs;
+    use std::os::unix::fs::PermissionsExt;
+
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    at.touch("file1");
+    at.touch("file2");
+
+    at.mkdir("noaccess");
+    at.write("noaccess/secret", "topsecret\n");
+    fs::set_permissions(at.plus("noaccess"), fs::Permissions::from_mode(0o000)).unwrap();
+
+    ucmd.args(&["file1", "noaccess/secret", "file2"])
+        .fails_with_code(1)
+        .stdout_is("==> file1 <==\n\n==> file2 <==\n")
+        .stderr_is("tail: cannot open 'noaccess/secret' for reading: Permission denied\n");
+
+    fs::set_permissions(at.plus("noaccess"), fs::Permissions::from_mode(0o700)).unwrap();
+}
+
 #[test]
 fn test_follow_redirect_stdin_name_retry() {
     // $ touch f && tail -F - < f