cat: fix usage on FUSE

Author: oech3

src/uu/cat/src/splice.rs

@@ -7,7 +7,7 @@ use super::{CatResult, FdReadable, InputHandle};
 use rustix::io::{read, write};
 use std::os::{fd::AsFd, unix::io::AsRawFd};
 
-use uucore::pipes::{MAX_ROOTLESS_PIPE_SIZE, pipe, splice, splice_exact};
+use uucore::pipes::{MAX_ROOTLESS_PIPE_SIZE, is_end_of_file, pipe, splice, splice_exact};
 
 const BUF_SIZE: usize = 1024 * 16;
 
@@ -30,15 +30,15 @@ pub(super) fn write_fast_using_splice<R: FdReadable, S: AsRawFd + AsFd>(
         loop {
             match splice(&handle.reader, &write_fd, MAX_ROOTLESS_PIPE_SIZE) {
                 Ok(1..) => {}
-                Ok(0) => return Ok(false),
+                Ok(0) => return Ok(!is_end_of_file(&handle.reader)),
                 Err(_) => return Ok(true),
             }
         }
     } else if let Ok((pipe_rd, pipe_wr)) = pipe() {
         // both of in/output are not pipe. needs broker to use splice() with additional costs
         loop {
             match splice(&handle.reader, &pipe_wr, MAX_ROOTLESS_PIPE_SIZE) {
-                Ok(0) => return Ok(false),
+                Ok(0) => return Ok(!is_end_of_file(&handle.reader)),
                 Ok(n) => {
                     if splice_exact(&pipe_rd, write_fd, n).is_err() {
                         // If the first splice manages to copy to the intermediate

src/uucore/Cargo.toml

@@ -37,7 +37,7 @@ jiff = { workspace = true, optional = true, features = [
   "tzdb-concatenated",
 ] }
 rustc-hash = { workspace = true }
-rustix = { workspace = true, features = ["fs", "pipe"] }
+rustix = { workspace = true, features = ["event", "fs", "time", "pipe"] }
 time = { workspace = true, optional = true, features = [
   "formatting",
   "local-offset",

src/uucore/src/lib/features/pipes.rs

@@ -52,6 +52,27 @@ pub fn splice(source: &impl AsFd, target: &impl AsFd, len: usize) -> std::io::Re
     )?)
 }
 
+/// check that splice reached to end of file
+/// ignore 2nd Ctrl + D
+/// <https://github.com/uutils/coreutils/issues/9609>
+#[inline]
+#[cfg(any(target_os = "linux", target_os = "android"))]
+pub fn is_end_of_file(source: &impl AsFd) -> bool {
+    use rustix::event::{PollFd, PollFlags, poll};
+    use rustix::time::Timespec;
+    let mut pfd = [PollFd::new(source, PollFlags::IN)];
+    matches!(
+        poll(
+            &mut pfd,
+            Some(&Timespec {
+                tv_sec: 0,
+                tv_nsec: 0
+            })
+        ),
+        Ok(0)
+    )
+}
+
 /// Splice wrapper which fully finishes the write.
 ///
 /// Exactly `len` bytes are moved from `source` into `target`.