From fbefc2bd9956596c9e6f986a7420132cf5be8603 Mon Sep 17 00:00:00 2001
From: Lorenzo Rossi <65499789+rossilor95@users.noreply.github.com>
Date: Sun, 19 Apr 2026 13:39:40 +0200
Subject: [PATCH] tail: fix panic on write error in bounded_tail (#11886)

* tail: fix panic on write error in bounded_tail

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* tail: increase test file size to ensure bounded_tail path

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
---
 src/uu/tail/src/tail.rs    | 14 ++++++++------
 tests/by-util/test_tail.rs | 15 +++++++++++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/uu/tail/src/tail.rs b/src/uu/tail/src/tail.rs
index 4c3cbee25..509a5619d 100644
--- a/src/uu/tail/src/tail.rs
+++ b/src/uu/tail/src/tail.rs
@@ -174,7 +174,7 @@ fn tail_file(
                     && file.is_seekable(if input.is_stdin() { offset } else { 0 })
                     && (!st.is_file() || st.len() > blksize_limit)
                 {
-                    bounded_tail(&mut file, settings);
+                    bounded_tail(&mut file, settings)?;
                     reader = BufReader::new(file);
                 } else {
                     reader = BufReader::new(file);
@@ -460,7 +460,7 @@ fn backwards_thru_file(file: &mut File, num_delimiters: u64, delimiter: u8) {
 /// end of the file, and then read the file "backwards" in blocks of size
 /// `BLOCK_SIZE` until we find the location of the first line/byte. This ends up
 /// being a nice performance win for very large files.
-fn bounded_tail(file: &mut File, settings: &Settings) {
+fn bounded_tail(file: &mut File, settings: &Settings) -> UResult<()> {
     debug_assert!(!settings.presume_input_pipe);
     let mut limit = None;
 
@@ -493,7 +493,8 @@ fn bounded_tail(file: &mut File, settings: &Settings) {
         _ => {}
     }
 
-    print_target_section(file, limit);
+    print_target_section(file, limit)?;
+    Ok(())
 }
 
 fn unbounded_tail<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
@@ -574,7 +575,7 @@ fn unbounded_tail<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UR
     Ok(())
 }
 
-fn print_target_section<R>(file: &mut R, limit: Option<u64>)
+fn print_target_section<R>(file: &mut R, limit: Option<u64>) -> UResult<()>
 where
     R: Read + ?Sized,
 {
@@ -583,10 +584,11 @@ where
     let mut stdout = stdout.lock();
     if let Some(limit) = limit {
         let mut reader = file.take(limit);
-        io::copy(&mut reader, &mut stdout).unwrap();
+        io::copy(&mut reader, &mut stdout)?;
     } else {
-        io::copy(file, &mut stdout).unwrap();
+        io::copy(file, &mut stdout)?;
     }
+    Ok(())
 }
 
 #[cfg(test)]
diff --git a/tests/by-util/test_tail.rs b/tests/by-util/test_tail.rs
index c1b755bda..d46ff112c 100644
--- a/tests/by-util/test_tail.rs
+++ b/tests/by-util/test_tail.rs
@@ -5086,6 +5086,21 @@ fn test_failed_write_is_reported() {
         .stderr_is("tail: No space left on device\n");
 }
 
+#[cfg(target_os = "linux")]
+#[test]
+fn test_failed_write_is_reported_on_seekable_input() {
+    let ts = TestScenario::new("tail");
+    let at = &ts.fixtures;
+
+    at.write("bigfile", &"x\n".repeat(1_100_000));
+
+    ts.ucmd()
+        .arg("bigfile")
+        .set_stdout(File::create("/dev/full").unwrap())
+        .fails()
+        .stderr_is("tail: No space left on device\n");
+}
+
 #[test]
 #[cfg(target_os = "linux")]
 fn test_dev_zero() {