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Commit | Line | Data |
---|---|---|
04454e1e FG |
1 | use std::fs::{File, OpenOptions}; |
2 | use std::io; | |
3 | use std::mem; | |
4 | use std::os::unix::prelude::*; | |
5 | use std::path::Path; | |
6 | ||
7 | #[derive(Debug)] | |
8 | pub struct Lock { | |
9 | file: File, | |
10 | } | |
11 | ||
12 | impl Lock { | |
13 | pub fn new(p: &Path, wait: bool, create: bool, exclusive: bool) -> io::Result<Lock> { | |
14 | let file = OpenOptions::new() | |
15 | .read(true) | |
16 | .write(true) | |
17 | .create(create) | |
18 | .mode(libc::S_IRWXU as u32) | |
19 | .open(p)?; | |
20 | ||
21 | let lock_type = if exclusive { libc::F_WRLCK } else { libc::F_RDLCK }; | |
22 | ||
23 | let mut flock: libc::flock = unsafe { mem::zeroed() }; | |
24 | flock.l_type = lock_type as libc::c_short; | |
25 | flock.l_whence = libc::SEEK_SET as libc::c_short; | |
26 | flock.l_start = 0; | |
27 | flock.l_len = 0; | |
28 | ||
29 | let cmd = if wait { libc::F_SETLKW } else { libc::F_SETLK }; | |
30 | let ret = unsafe { libc::fcntl(file.as_raw_fd(), cmd, &flock) }; | |
31 | if ret == -1 { Err(io::Error::last_os_error()) } else { Ok(Lock { file }) } | |
32 | } | |
33 | ||
34 | pub fn error_unsupported(err: &io::Error) -> bool { | |
35 | matches!(err.raw_os_error(), Some(libc::ENOTSUP) | Some(libc::ENOSYS)) | |
36 | } | |
37 | } | |
38 | ||
39 | impl Drop for Lock { | |
40 | fn drop(&mut self) { | |
41 | let mut flock: libc::flock = unsafe { mem::zeroed() }; | |
42 | flock.l_type = libc::F_UNLCK as libc::c_short; | |
43 | flock.l_whence = libc::SEEK_SET as libc::c_short; | |
44 | flock.l_start = 0; | |
45 | flock.l_len = 0; | |
46 | ||
47 | unsafe { | |
48 | libc::fcntl(self.file.as_raw_fd(), libc::F_SETLK, &flock); | |
49 | } | |
50 | } | |
51 | } |