From fa5c9dc8cc57d2678f7c4632af5f79d7a8619d49 Mon Sep 17 00:00:00 2001
From: oech3 <79379754+oech3@users.noreply.github.com>
Date: Sun, 26 Apr 2026 20:05:40 +0900
Subject: [PATCH] extend pipe size if possible

---
 src/main.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index d4bf114..21d1938 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,23 +13,25 @@ use std::fs::File;
 use std::io;
 use std::os::unix::io::{AsRawFd, RawFd};
 
-use nix::fcntl::{splice, SpliceFFlags};
+use nix::fcntl::{fcntl, FcntlArg, splice, SpliceFFlags};
 use nix::unistd::pipe;
 
-const BUF_SIZE: usize = 16384;
+const MAX_ROOTLESS_PIPE_SIZE: usize = 1024 * 1024;
 
 #[inline]
 fn cat<T: AsRawFd>(input: &T, pipe_rd: RawFd, pipe_wr: RawFd) {
     let stdout = io::stdout();
     let _handle = stdout.lock();
 
+    let _ = fcntl(pipe_wr, FcntlArg::F_SETPIPE_SZ(MAX_ROOTLESS_PIPE_SIZE as i32));
+
     loop {
         let res = splice(
             input.as_raw_fd(),
             None,
             pipe_wr,
             None,
-            BUF_SIZE,
+            MAX_ROOTLESS_PIPE_SIZE,
             SpliceFFlags::empty(),
         )
         .unwrap();
@@ -45,7 +47,7 @@ fn cat<T: AsRawFd>(input: &T, pipe_rd: RawFd, pipe_wr: RawFd) {
             None,
             stdout.as_raw_fd(),
             None,
-            BUF_SIZE,
+            MAX_ROOTLESS_PIPE_SIZE,
             SpliceFFlags::empty(),
         )
         .unwrap();