du: count links based on inode

src/uu/du/src/du.rs

@@ -1080,6 +1080,9 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let (print_tx, rx) = mpsc::channel::<UResult<StatPrintInfo>>();
     let printing_thread = thread::spawn(move || stat_printer.print_stats(&rx));
 
+    // Check existence of path provided in argument
+    let mut seen_inodes: HashSet<FileInfo> = HashSet::new();
+
     'loop_file: for path in files {
         // Skip if we don't want to ignore anything
         if !&traversal_options.excludes.is_empty() {
@@ -1098,9 +1101,6 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             }
         }
 
-        // Check existence of path provided in argument
-        let mut seen_inodes: HashSet<FileInfo> = HashSet::new();
-
         // Determine which traversal method to use
         #[cfg(all(unix, not(target_os = "redox")))]
         let use_safe_traversal = traversal_options.dereference != Deref::All;
@@ -1114,6 +1114,9 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
                 // Pre-populate seen_inodes with the starting directory to detect cycles
                 if let Ok(stat) = Stat::new(&path, None, &traversal_options) {
                     if let Some(inode) = stat.inode {
+                        if !traversal_options.count_links && seen_inodes.contains(&inode) {
+                            continue 'loop_file;
+                        }
                         seen_inodes.insert(inode);
                     }
                 }
@@ -1147,6 +1150,9 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             // Use regular traversal (non-Linux or when -L is used)
             if let Ok(stat) = Stat::new(&path, None, &traversal_options) {
                 if let Some(inode) = stat.inode {
+                    if !traversal_options.count_links && seen_inodes.contains(&inode) {
+                        continue 'loop_file;
+                    }
                     seen_inodes.insert(inode);
                 }
                 let stat = du_regular(

tests/by-util/test_du.rs

@@ -2003,3 +2003,58 @@ fn test_du_long_path_from_unreadable() {
     perms.set_mode(0o755);
     fs::set_permissions(&inaccessible_path, perms).unwrap();
 }
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_du_hard_links_multiple_dirs_in_args() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("dir1");
+    at.mkdir("dir2");
+    at.write("dir1/file", "hello world");
+    at.hard_link("dir1/file", "dir2/link");
+
+    let result = ts.ucmd().args(&["dir1", "dir2"]).succeeds();
+    let lines: Vec<&str> = result.stdout_str().lines().collect();
+    let size = |i: usize| lines[i].split_once('\t').unwrap().0.parse::<u64>().unwrap();
+    assert!(size(0) > size(1));
+}
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_du_hard_links_multiple_links_in_args() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("dir1");
+    at.write("dir1/file", "hello world");
+    at.hard_link("dir1/file", "dir1/link");
+
+    let result = ts.ucmd().args(&["dir1/file", "dir1/link"]).succeeds();
+    result.stdout_contains("dir1/file");
+    result.stdout_does_not_contain("dir1/link");
+
+    let result = ts.ucmd().args(&["-L", "dir1/file", "dir1/link"]).succeeds();
+    result.stdout_contains("dir1/file");
+    result.stdout_does_not_contain("dir1/link");
+}
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_du_symlinks_multiple_links_in_args() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("dir1");
+    at.write("dir1/file", "hello world");
+    at.symlink_file("dir1/file", "dir1/link");
+
+    let result = ts.ucmd().args(&["dir1/file", "dir1/link"]).succeeds();
+    result.stdout_contains("dir1/file");
+    result.stdout_contains("dir1/link");
+
+    let result = ts.ucmd().args(&["-L", "dir1/file", "dir1/link"]).succeeds();
+    result.stdout_contains("dir1/file");
+    result.stdout_does_not_contain("dir1/link");
+}