rclone/chtimes_linux.go
2012-12-26 12:27:26 +00:00

78 lines
2 KiB
Go

// An implementation of Chtimes which preserves nanosecond precision under linux
//
// Should go in standard library, but here for now
// +build linux
package main
import (
"os"
"syscall"
"time"
"unsafe"
)
// COPIED from syscall
// byteSliceFromString returns a NUL-terminated slice of bytes
// containing the text of s. If s contains a NUL byte at any
// location, it returns (nil, EINVAL).
func byteSliceFromString(s string) ([]byte, error) {
for i := 0; i < len(s); i++ {
if s[i] == 0 {
return nil, syscall.EINVAL
}
}
a := make([]byte, len(s)+1)
copy(a, s)
return a, nil
}
// COPIED from syscall
// bytePtrFromString returns a pointer to a NUL-terminated array of
// bytes containing the text of s. If s contains a NUL byte at any
// location, it returns (nil, EINVAL).
func bytePtrFromString(s string) (*byte, error) {
a, err := byteSliceFromString(s)
if err != nil {
return nil, err
}
return &a[0], nil
}
// COPIED from syscall auto generated code modified from utimes
func utimensat(dirfd int, path string, times *[2]syscall.Timespec) (err error) {
var _p0 *byte
_p0, err = bytePtrFromString(path)
if err != nil {
return
}
_, _, e1 := syscall.Syscall(syscall.SYS_UTIMENSAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(times)))
if e1 != 0 {
err = e1
}
return
}
// FIXME needs defining properly!
const AT_FDCWD = -100
// COPIED from syscall and modified
//sys utimes(path string, times *[2]Timeval) (err error)
func Utimensat(dirfd int, path string, ts []syscall.Timespec) (err error) {
if len(ts) != 2 {
return syscall.EINVAL
}
return utimensat(dirfd, path, (*[2]syscall.Timespec)(unsafe.Pointer(&ts[0])))
}
// COPIED from syscall and modified
func Chtimes(name string, atime time.Time, mtime time.Time) error {
var utimes [2]syscall.Timespec
utimes[0] = syscall.NsecToTimespec(atime.UnixNano())
utimes[1] = syscall.NsecToTimespec(mtime.UnixNano())
if e := Utimensat(AT_FDCWD, name, utimes[0:]); e != nil {
return &os.PathError{Op: "chtimes", Path: name, Err: e}
}
return nil
}