40 lines
1.3 KiB
Rust
40 lines
1.3 KiB
Rust
//! We use `flock` rather than `fcntl` on Linux, because WSL1 does not support
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//! `fcntl`-style advisory locks properly (rust-lang/rust#72157). For other Unix
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//! targets we still use `fcntl` because it's more portable than `flock`.
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use std::fs::{File, OpenOptions};
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use std::io;
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use std::os::unix::prelude::*;
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use std::path::Path;
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#[derive(Debug)]
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pub struct Lock {
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_file: File,
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}
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impl Lock {
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pub fn new(p: &Path, wait: bool, create: bool, exclusive: bool) -> io::Result<Lock> {
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let file = OpenOptions::new()
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.read(true)
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.write(true)
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.create(create)
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.mode(libc::S_IRWXU as u32)
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.open(p)?;
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let mut operation = if exclusive { libc::LOCK_EX } else { libc::LOCK_SH };
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if !wait {
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operation |= libc::LOCK_NB
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}
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let ret = unsafe { libc::flock(file.as_raw_fd(), operation) };
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if ret == -1 { Err(io::Error::last_os_error()) } else { Ok(Lock { _file: file }) }
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}
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pub fn error_unsupported(err: &io::Error) -> bool {
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matches!(err.raw_os_error(), Some(libc::ENOTSUP) | Some(libc::ENOSYS))
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}
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}
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// Note that we don't need a Drop impl to execute `flock(fd, LOCK_UN)`. A lock acquired by
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// `flock` is associated with the file descriptor and closing the file releases it
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// automatically.
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