Auto merge of #266 - kamalmarhubi:linux-sendfile, r=arcnmx

linux: Add sendfile(2)

Author: homu

Cargo.toml

@@ -20,12 +20,13 @@ preadv_pwritev = []
 signalfd = []
 
 [dependencies]
-libc     = "0.2.4"
+libc     = "0.2.7"
 bitflags = "0.3.3"
 
 [dev-dependencies]
 rand = "0.3.8"
 tempdir = "0.3"
+tempfile = "2"
 nix-test = { path = "nix-test" }
 
 [[test]]

src/sys/mod.rs

@@ -16,6 +16,9 @@ pub mod memfd;
 #[cfg(not(any(target_os = "ios", target_os = "freebsd", target_os = "dragonfly")))]
 pub mod ioctl;
 
+#[cfg(any(target_os = "linux", target_os = "android"))]
+pub mod sendfile;
+
 pub mod signal;
 
 #[cfg(any(target_os = "linux", target_os = "android"))]

src/sys/sendfile.rs

@@ -0,0 +1,12 @@
+use std::os::unix::io::RawFd;
+use std::ptr;
+
+use libc::{self, off_t};
+
+use {Errno, Result};
+
+pub fn sendfile(out_fd: RawFd, in_fd: RawFd, offset: Option<&mut off_t>, count: usize) -> Result<usize> {
+    let offset = offset.map(|offset| offset as *mut _).unwrap_or(ptr::null_mut());
+    let ret = unsafe { libc::sendfile(out_fd, in_fd, offset, count) };
+    Errno::result(ret).map(|r| r as usize)
+}

test/test.rs

@@ -3,12 +3,15 @@ extern crate nix;
 extern crate libc;
 extern crate rand;
 extern crate tempdir;
+extern crate tempfile;
 
 extern crate nix_test as nixtest;
 
 mod sys;
 mod test_net;
 mod test_nix_path;
+#[cfg(any(target_os = "linux", target_os = "android"))]
+mod test_sendfile;
 mod test_stat;
 mod test_unistd;
 

test/test_sendfile.rs

@@ -0,0 +1,30 @@
+use std::io::prelude::*;
+use std::os::unix::prelude::*;
+
+use tempfile::tempfile;
+
+use libc::off_t;
+
+use nix::unistd::{close, pipe, read};
+use nix::sys::sendfile::sendfile;
+
+#[test]
+fn test_sendfile() {
+    const CONTENTS: &'static [u8] = b"abcdef123456";
+    let mut tmp = tempfile().unwrap();
+    tmp.write(CONTENTS).unwrap();
+
+    let (rd, wr) = pipe().unwrap();
+    let mut offset: off_t = 5;
+    let res = sendfile(wr, tmp.as_raw_fd(), Some(&mut offset), 2).unwrap();
+
+    assert_eq!(2, res);
+
+    let mut buf = [0u8; 1024];
+    assert_eq!(2, read(rd, &mut buf).unwrap());
+    assert_eq!(b"f1", &buf[0..2]);
+    assert_eq!(7, offset);
+
+    close(rd).unwrap();
+    close(wr).unwrap();
+}