tools: fd: improve drop handler and add some helpers

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
This commit is contained in:
Wolfgang Bumiller 2019-08-21 10:52:37 +02:00
parent 68f4a68bc1
commit 4a1c914827

View File

@ -2,6 +2,10 @@
use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
use nix::fcntl::OFlag;
use nix::sys::stat::Mode;
use nix::NixPath;
/// Guard a raw file descriptor with a drop handler. This is mostly useful when access to an owned
/// `RawFd` is required without the corresponding handler object (such as when only the file
/// descriptor number is required in a closure which may be dropped instead of being executed).
@ -9,7 +13,8 @@ pub struct Fd(pub RawFd);
impl Drop for Fd {
fn drop(&mut self) {
if self.0 != -1 {
// `>= 0` instead of `!= -1` to also handle things like AT_FDCWD
if self.0 >= 0 {
unsafe {
libc::close(self.0);
}
@ -36,3 +41,24 @@ impl FromRawFd for Fd {
Self(fd)
}
}
impl Fd {
pub const fn cwd() -> Self {
Self(libc::AT_FDCWD)
}
pub fn open<P>(path: &P, oflag: OFlag, mode: Mode) -> Result<Self, nix::Error>
where
P: ?Sized + NixPath,
{
nix::fcntl::open(path, oflag, mode).map(Self)
}
pub fn openat<D, P>(dirfd: D, path: &P, oflag: OFlag, mode: Mode) -> Result<Self, nix::Error>
where
D: AsRawFd,
P: ?Sized + NixPath,
{
nix::fcntl::openat(dirfd.as_raw_fd(), path, oflag, mode).map(Self)
}
}