blob: 4c2a7236dcc7fd9f41254e8633d7f4ae8c3f8350 [file] [log] [blame]
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cache
import (
func init() {
checkPathValid = darwinCheckPathValid
func darwinCheckPathValid(path string) error {
// Darwin provides fcntl(F_GETPATH) to get a path for an arbitrary FD.
// Conveniently for our purposes, it gives the canonical case back. But
// there's no guarantee that it will follow the same route through the
// filesystem that the original path did.
path, err := filepath.Abs(path)
if err != nil {
return err
fd, err := syscall.Open(path, os.O_RDONLY, 0)
if err != nil {
return err
defer syscall.Close(fd)
buf := make([]byte, 4096) // No MAXPATHLEN in syscall, I think it's 1024, this is bigger.
// Wheeee! syscall doesn't expose a way to call Fcntl except FcntlFlock.
// As of writing, it just passes the pointer through, so we can just lie.
if err := syscall.FcntlFlock(uintptr(fd), syscall.F_GETPATH, (*syscall.Flock_t)(unsafe.Pointer(&buf[0]))); err != nil {
return err
buf = buf[:bytes.IndexByte(buf, 0)]
isRoot := func(p string) bool {
return p[len(p)-1] == filepath.Separator
// Darwin seems to like having multiple names for the same folder. Match as much of the suffix as we can.
for got, want := path, string(buf); !isRoot(got) && !isRoot(want); got, want = filepath.Dir(got), filepath.Dir(want) {
g, w := filepath.Base(got), filepath.Base(want)
if !strings.EqualFold(g, w) {
if g != w {
return fmt.Errorf("invalid path %q: component %q is listed by macOS as %q", path, g, w)
return nil