rustc_data_structures/flock/
linux.rs

Help
1//! We use `flock` rather than `fcntl` on Linux, because WSL1 does not support
2//! `fcntl`-style advisory locks properly (rust-lang/rust#72157). For other Unix
3//! targets we still use `fcntl` because it's more portable than `flock`.
4
5use std::fs::{File, OpenOptions};
6use std::io;
7use std::os::unix::prelude::*;
8use std::path::Path;
9
10#[derive(Debug)]
11pub struct Lock {
12    _file: File,
13}
14
15impl Lock {
16    pub fn new(p: &Path, wait: bool, create: bool, exclusive: bool) -> io::Result<Lock> {
17        let file = OpenOptions::new().read(true).write(true).create(create).mode(0o600).open(p)?;
18
19        let mut operation = if exclusive { libc::LOCK_EX } else { libc::LOCK_SH };
20        if !wait {
21            operation |= libc::LOCK_NB
22        }
23
24        let ret = unsafe { libc::flock(file.as_raw_fd(), operation) };
25        if ret == -1 { Err(io::Error::last_os_error()) } else { Ok(Lock { _file: file }) }
26    }
27
28    pub fn error_unsupported(err: &io::Error) -> bool {
29        matches!(err.raw_os_error(), Some(libc::ENOTSUP) | Some(libc::ENOSYS))
30    }
31}
32
33// Note that we don't need a Drop impl to execute `flock(fd, LOCK_UN)`. A lock acquired by
34// `flock` is associated with the file descriptor and closing the file releases it
35// automatically.
rustc_data_structures/flock/linux.rs

rustc_data_structures/flock/
linux.rs
