From c9efbfac5f8ca60af29ef97edcbcf96b26a3220b Mon Sep 17 00:00:00 2001
From: Chaganti-Reddy <chagantivenkataramireddy4@gmail.com>
Date: Fri, 10 Jul 2026 16:43:59 +0530
Subject: [PATCH] cp: don't hang forever when the backup destination is a fifo.
 Fixes #13162

---
 src/uu/cp/src/cp.rs      |  5 +++++
 tests/by-util/test_cp.rs | 21 +++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/uu/cp/src/cp.rs b/src/uu/cp/src/cp.rs
index 7129e82522..e118714218 100644
--- a/src/uu/cp/src/cp.rs
+++ b/src/uu/cp/src/cp.rs
@@ -2015,6 +2015,11 @@ fn backup_dest(dest: &Path, backup_path: &Path, is_dest_symlink: bool) -> CopyRe
     if is_dest_symlink {
         fs::rename(dest, backup_path)?;
     } else {
+        match fs::remove_file(backup_path) {
+            Ok(()) => {}
+            Err(err) if err.kind() == io::ErrorKind::NotFound => {}
+            Err(err) => return Err(err.into()),
+        }
         fs::copy(dest, backup_path)?;
     }
     Ok(())
diff --git a/tests/by-util/test_cp.rs b/tests/by-util/test_cp.rs
index d973c39366..48e093e60c 100644
--- a/tests/by-util/test_cp.rs
+++ b/tests/by-util/test_cp.rs
@@ -1243,6 +1243,27 @@ fn test_cp_backup_existing() {
     );
 }
 
+#[test]
+#[cfg(unix)]
+fn test_cp_backup_existing_target_is_fifo() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkfifo(&format!("{TEST_HOW_ARE_YOU_SOURCE}~"));
+
+    ucmd.arg("--backup=simple")
+        .arg(TEST_HELLO_WORLD_SOURCE)
+        .arg(TEST_HOW_ARE_YOU_SOURCE)
+        .timeout(Duration::from_secs(10))
+        .succeeds()
+        .no_stderr();
+
+    assert_eq!(at.read(TEST_HOW_ARE_YOU_SOURCE), "Hello, World!\n");
+    assert!(!at.is_fifo(&format!("{TEST_HOW_ARE_YOU_SOURCE}~")));
+    assert_eq!(
+        at.read(&format!("{TEST_HOW_ARE_YOU_SOURCE}~")),
+        "How are you?\n"
+    );
+}
+
 #[test]
 fn test_cp_backup_nil() {
     let (at, mut ucmd) = at_and_ucmd!();