diff --git a/CHANGELOG.md b/CHANGELOG.md index fda5b6905b..24f353c2d7 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -17,6 +17,8 @@ This project adheres to [Semantic Versioning](http://semver.org/). ([#1010](https://github.com/nix-rust/nix/pull/1010)) - Added `nix::sys::signal::signal`. ([#817](https://github.com/nix-rust/nix/pull/817)) +- Added `copy_file_range` wrapper + ([#1008](https://github.com/nix-rust/nix/pull/1008)) ### Changed ### Fixed diff --git a/src/fcntl.rs b/src/fcntl.rs index a763c10f9a..d2efb67cc1 100644 --- a/src/fcntl.rs +++ b/src/fcntl.rs @@ -246,6 +246,9 @@ pub enum FcntlArg<'a> { } pub use self::FcntlArg::*; +#[cfg(any(target_os = "android", target_os = "linux"))] +use std::ptr; + // TODO: Figure out how to handle value fcntl returns pub fn fcntl(fd: RawFd, arg: FcntlArg) -> Result { let res = unsafe { @@ -305,6 +308,36 @@ pub fn flock(fd: RawFd, arg: FlockArg) -> Result<()> { Errno::result(res).map(drop) } +/// Copy a range of data from one file to another +/// +/// The `copy_file_range` system call performs an in-kernel copy between +/// file descriptor `fd_in` and `fd_out` without the additional cost of transferring data +/// from the kernel to user space and then back into the kernel. It +/// copies up to `len` bytes of data from file descriptor `fd_in` to file +/// descriptor `fd_out`, overwriting any data that exists within the +/// requested range of the target file. +/// +/// If the `off_in` and/or `off_out` arguments are used, the values +/// will be mutated to reflect the new position within the file after +/// copying. If they are not used, the relevant filedescriptors will be seeked +/// to the new position. +/// +/// On completion the number of bytes actually copied will be returned. +#[cfg(any(target_os = "android", target_os = "linux"))] +pub fn copy_file_range( + fd_in: RawFd, off_in: Option<&mut i64>, + fd_out: RawFd, off_out: Option<&mut i64>, + len: usize) -> Result { + + let off_in = off_in.map(|offset| offset as *mut _).unwrap_or(ptr::null_mut()); + let off_out = off_out.map(|offset| offset as *mut _).unwrap_or(ptr::null_mut()); + + let ret = unsafe { + libc::syscall(libc::SYS_copy_file_range, fd_in, off_in, fd_out, off_out, len, 0) + }; + Errno::result(ret).map(|r| r as usize) +} + #[cfg(any(target_os = "android", target_os = "linux"))] libc_bitflags! { /// Additional flags to `splice` and friends. @@ -329,8 +362,7 @@ libc_bitflags! { #[cfg(any(target_os = "linux", target_os = "android"))] pub fn splice(fd_in: RawFd, off_in: Option<&mut libc::loff_t>, fd_out: RawFd, off_out: Option<&mut libc::loff_t>, - len: usize, flags: SpliceFFlags) -> Result { - use std::ptr; + len: usize, flags: SpliceFFlags) -> Result { let off_in = off_in.map(|offset| offset as *mut _).unwrap_or(ptr::null_mut()); let off_out = off_out.map(|offset| offset as *mut _).unwrap_or(ptr::null_mut()); diff --git a/test/test_fcntl.rs b/test/test_fcntl.rs index bcc523bfcc..a4c3611989 100644 --- a/test/test_fcntl.rs +++ b/test/test_fcntl.rs @@ -49,15 +49,49 @@ fn test_readlink() { mod linux_android { use std::io::prelude::*; use std::os::unix::prelude::*; + use std::io::SeekFrom; use libc::loff_t; - use nix::fcntl::{SpliceFFlags, FallocateFlags, fallocate, splice, tee, vmsplice}; + use nix::fcntl::{SpliceFFlags, FallocateFlags, fallocate, splice, tee, vmsplice, copy_file_range}; use nix::sys::uio::IoVec; use nix::unistd::{close, pipe, read, write}; use tempfile::{tempfile, NamedTempFile}; + /// This test creates a temporary file containing the contents + /// 'foobarbaz' and uses the `copy_file_range` call to transfer + /// 3 bytes at offset 3 (`bar`) to another empty file at offset 0. The + /// resulting file is read and should contain the contents `bar`. + /// The from_offset should be updated by the call to reflect + /// the 3 bytes read (6). + /// + /// Fix me: test is disabled for linux based builds, because Jenkins + /// Linux version is too old for `copy_file_range`. Should work + /// on netbsd build. + #[test] + #[cfg_attr(target_env = "linux", ignore)] + fn test_copy_file_range() { + const CONTENTS: &[u8] = b"foobarbaz"; + + let mut tmp1 = tempfile().unwrap(); + let mut tmp2 = tempfile().unwrap(); + + tmp1.write_all(CONTENTS).unwrap(); + tmp1.flush().unwrap(); + + let mut from_offset: i64 = 3; + copy_file_range(tmp1.as_raw_fd(), Some(&mut from_offset), + tmp2.as_raw_fd(), None, 3).unwrap(); + + let mut res: String = String::new(); + tmp2.seek(SeekFrom::Start(0)).unwrap(); + tmp2.read_to_string(&mut res).unwrap(); + + assert_eq!(res, String::from("bar")); + assert_eq!(from_offset, 6); + } + #[test] fn test_splice() { const CONTENTS: &[u8] = b"abcdef123456";