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//! On Linux we try to use the more accurate `utimensat` syscall but this isn't
//! always available so we also fall back to `utimes` if we couldn't find
//! `utimensat` at runtime.
use crate::FileTime;
use std::ffi::CString;
use std::fs;
use std::io;
use std::os::unix::prelude::*;
use std::path::Path;
use std::ptr;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering::SeqCst;
pub fn set_file_times(p: &Path, atime: FileTime, mtime: FileTime) -> io::Result<()> {
set_times(p, Some(atime), Some(mtime), false)
}
pub fn set_file_mtime(p: &Path, mtime: FileTime) -> io::Result<()> {
set_times(p, None, Some(mtime), false)
}
pub fn set_file_atime(p: &Path, atime: FileTime) -> io::Result<()> {
set_times(p, Some(atime), None, false)
}
pub fn set_file_handle_times(
f: &fs::File,
atime: Option<FileTime>,
mtime: Option<FileTime>,
) -> io::Result<()> {
// Attempt to use the `utimensat` syscall, but if it's not supported by the
// current kernel then fall back to an older syscall.
static INVALID: AtomicBool = AtomicBool::new(false);
if !INVALID.load(SeqCst) {
let times = [super::to_timespec(&atime), super::to_timespec(&mtime)];
// We normally use a syscall because the `utimensat` function is documented
// as not accepting a file descriptor in the first argument (even though, on
// Linux, the syscall itself can accept a file descriptor there).
#[cfg(not(target_env = "musl"))]
let rc = unsafe {
libc::syscall(
libc::SYS_utimensat,
f.as_raw_fd(),
ptr::null::<libc::c_char>(),
times.as_ptr(),
0,
)
};
// However, on musl, we call the musl libc function instead. This is because
// on newer musl versions starting with musl 1.2, `timespec` is always a 64-bit
// value even on 32-bit targets. As a result, musl internally converts their
// `timespec` values to the correct ABI before invoking the syscall. Since we
// use `timespec` from the libc crate, it matches musl's definition and not
// the Linux kernel's version (for some platforms) so we must use musl's
// `utimensat` function to properly convert the value. musl's `utimensat`
// function allows file descriptors in the path argument so this is fine.
#[cfg(target_env = "musl")]
let rc = unsafe {
libc::utimensat(
f.as_raw_fd(),
ptr::null::<libc::c_char>(),
times.as_ptr(),
0,
)
};
if rc == 0 {
return Ok(());
}
let err = io::Error::last_os_error();
if err.raw_os_error() == Some(libc::ENOSYS) {
INVALID.store(true, SeqCst);
} else {
return Err(err);
}
}
super::utimes::set_file_handle_times(f, atime, mtime)
}
pub fn set_symlink_file_times(p: &Path, atime: FileTime, mtime: FileTime) -> io::Result<()> {
set_times(p, Some(atime), Some(mtime), true)
}
fn set_times(
p: &Path,
atime: Option<FileTime>,
mtime: Option<FileTime>,
symlink: bool,
) -> io::Result<()> {
let flags = if symlink {
libc::AT_SYMLINK_NOFOLLOW
} else {
0
};
// Same as the `if` statement above.
static INVALID: AtomicBool = AtomicBool::new(false);
if !INVALID.load(SeqCst) {
let p = CString::new(p.as_os_str().as_bytes())?;
let times = [super::to_timespec(&atime), super::to_timespec(&mtime)];
let rc = unsafe { libc::utimensat(libc::AT_FDCWD, p.as_ptr(), times.as_ptr(), flags) };
if rc == 0 {
return Ok(());
}
let err = io::Error::last_os_error();
if err.raw_os_error() == Some(libc::ENOSYS) {
INVALID.store(true, SeqCst);
} else {
return Err(err);
}
}
super::utimes::set_times(p, atime, mtime, symlink)
}
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