rclone/backend/local/lchmod_unix.go

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//go:build !windows && !plan9 && !js && !linux
package local
import (
"os"
"syscall"
"golang.org/x/sys/unix"
)
const haveLChmod = true
// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
//
// Borrowed from the syscall source since it isn't public.
func syscallMode(i os.FileMode) (o uint32) {
o |= uint32(i.Perm())
if i&os.ModeSetuid != 0 {
o |= syscall.S_ISUID
}
if i&os.ModeSetgid != 0 {
o |= syscall.S_ISGID
}
if i&os.ModeSticky != 0 {
o |= syscall.S_ISVTX
}
return o
}
// lChmod changes the mode of the named file to mode. If the file is a symbolic
// link, it changes the link, not the target. If there is an error,
// it will be of type *PathError.
func lChmod(name string, mode os.FileMode) error {
// NB linux does not support AT_SYMLINK_NOFOLLOW as a parameter to fchmodat
// and returns ENOTSUP if you try, so we don't support this on linux
if e := unix.Fchmodat(unix.AT_FDCWD, name, syscallMode(mode), unix.AT_SYMLINK_NOFOLLOW); e != nil {
return &os.PathError{Op: "lChmod", Path: name, Err: e}
}
return nil
}