head: make process fail when writing to /dev/full

DaringCuteSeal · DaringCuteSeal · commit 4ae10b062b8c · 2025-01-04T12:04:48.000+07:00
diff --git a/src/uu/head/src/head.rs b/src/uu/head/src/head.rs
@@ -7,7 +7,7 @@
 
 use clap::{crate_version, Arg, ArgAction, ArgMatches, Command};
 use std::ffi::OsString;
-use std::io::{self, BufWriter, ErrorKind, Read, Seek, SeekFrom, Write};
+use std::io::{self, ErrorKind, Read, Seek, SeekFrom, Write};
 use std::num::TryFromIntError;
 use thiserror::Error;
 use uucore::display::Quotable;
@@ -18,9 +18,6 @@ use uucore::{format_usage, help_about, help_usage, show};
 
 const BUF_SIZE: usize = 65536;
 
-/// The capacity in bytes for buffered writers.
-const BUFWRITER_CAPACITY: usize = 16_384; // 16 kilobytes
-
 const ABOUT: &str = help_about!("head.md");
 const USAGE: &str = help_usage!("head.md");
 
@@ -254,6 +251,7 @@ where
     let mut stdout = stdout.lock();
 
     io::copy(&mut reader, &mut stdout)?;
+    stdout.flush()?;
 
     Ok(())
 }
@@ -263,11 +261,10 @@ fn read_n_lines(input: &mut impl std::io::BufRead, n: u64, separator: u8) -> std
     let mut reader = take_lines(input, n, separator);
 
     // Write those bytes to `stdout`.
-    let stdout = std::io::stdout();
-    let stdout = stdout.lock();
-    let mut writer = BufWriter::with_capacity(BUFWRITER_CAPACITY, stdout);
+    let mut stdout = std::io::stdout();
 
-    io::copy(&mut reader, &mut writer)?;
+    io::copy(&mut reader, &mut stdout)?;
+    stdout.flush()?;
 
     Ok(())
 }
diff --git a/tests/by-util/test_head.rs b/tests/by-util/test_head.rs
@@ -476,6 +476,12 @@ fn test_all_but_last_lines() {
         .stdout_is_fixture("lorem_ipsum_backwards_15_lines.expected");
 }
 
+#[cfg(any(
+    target_os = "linux",
+    target_os = "android",
+    target_os = "freebsd",
+    target_os = "netbsd"
+))]
 #[test]
 fn test_write_to_dev_full() {
     use std::fs::OpenOptions;
