diff options
-rw-r--r-- | sys_util/src/file_flags.rs | 53 | ||||
-rw-r--r-- | sys_util/src/lib.rs | 2 |
2 files changed, 55 insertions, 0 deletions
diff --git a/sys_util/src/file_flags.rs b/sys_util/src/file_flags.rs new file mode 100644 index 0000000..c8a3637 --- /dev/null +++ b/sys_util/src/file_flags.rs @@ -0,0 +1,53 @@ +// Copyright 2018 The Chromium OS Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +use std::os::unix::io::AsRawFd; + +use libc::{fcntl, F_GETFL, O_ACCMODE, O_RDONLY, O_WRONLY, O_RDWR, EINVAL}; + +use {Error, Result, errno_result}; + +#[derive(Copy, Clone, Debug, Eq, PartialEq)] +pub enum FileFlags { + Read, + Write, + ReadWrite, +} + +impl FileFlags { + pub fn from_file(file: &AsRawFd) -> Result<FileFlags> { + // Trivially safe because fcntl with the F_GETFL command is totally safe and we check for + // error. + let flags = unsafe { fcntl(file.as_raw_fd(), F_GETFL) }; + if flags == -1 { + errno_result() + } else { + match flags & O_ACCMODE { + O_RDONLY => Ok(FileFlags::Read), + O_WRONLY => Ok(FileFlags::Write), + O_RDWR => Ok(FileFlags::ReadWrite), + _ => Err(Error::new(EINVAL)), + } + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use {pipe, EventFd}; + + #[test] + fn pipe_pair() { + let (read_pipe, write_pipe) = pipe(true).unwrap(); + assert_eq!(FileFlags::from_file(&read_pipe).unwrap(), FileFlags::Read); + assert_eq!(FileFlags::from_file(&write_pipe).unwrap(), FileFlags::Write); + } + + #[test] + fn eventfd() { + let evt = EventFd::new().unwrap(); + assert_eq!(FileFlags::from_file(&evt).unwrap(), FileFlags::ReadWrite); + } +} diff --git a/sys_util/src/lib.rs b/sys_util/src/lib.rs index d9c5825..701622b 100644 --- a/sys_util/src/lib.rs +++ b/sys_util/src/lib.rs @@ -32,6 +32,7 @@ mod fork; mod signalfd; mod sock_ctrl_msg; mod passwd; +mod file_flags; pub use mmap::*; pub use shm::*; @@ -51,6 +52,7 @@ pub use ioctl::*; pub use sock_ctrl_msg::*; pub use passwd::*; pub use poll_token_derive::*; +pub use file_flags::*; pub use mmap::Error as MmapError; pub use guest_memory::Error as GuestMemoryError; |