741bf0726e
Protip: find naked *at syscalls using:
git grep "syscall." | grep "at(" | grep -v syscallcompat
125 lines
2.8 KiB
Go
125 lines
2.8 KiB
Go
package syscallcompat
|
|
|
|
import (
|
|
"os"
|
|
"path/filepath"
|
|
"sync"
|
|
"syscall"
|
|
)
|
|
|
|
// Sorry, fallocate is not available on OSX at all and
|
|
// fcntl F_PREALLOCATE is not accessible from Go.
|
|
// See https://github.com/rfjakob/gocryptfs/issues/18 if you want to help.
|
|
func EnospcPrealloc(fd int, off int64, len int64) (err error) {
|
|
return nil
|
|
}
|
|
|
|
// See above.
|
|
func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
|
|
return syscall.EOPNOTSUPP
|
|
}
|
|
|
|
var chdirMutex sync.Mutex
|
|
|
|
// Poor man's Openat
|
|
func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
|
|
chdirMutex.Lock()
|
|
defer chdirMutex.Unlock()
|
|
if !filepath.IsAbs(path) {
|
|
// Save the old working directory
|
|
oldWd, err := os.Getwd()
|
|
if err != nil {
|
|
return -1, err
|
|
}
|
|
// Chdir to target directory
|
|
err = syscall.Fchdir(dirfd)
|
|
if err != nil {
|
|
return -1, err
|
|
}
|
|
// Chdir back at the end
|
|
defer os.Chdir(oldWd)
|
|
}
|
|
return syscall.Open(path, flags, mode)
|
|
}
|
|
|
|
// Poor man's Renameat
|
|
func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
|
|
chdirMutex.Lock()
|
|
defer chdirMutex.Unlock()
|
|
// Unless both paths are absolute we have to save the old working dir and
|
|
// Chdir(oldWd) back to it in the end. If we error out before the first
|
|
// chdir, Chdir(oldWd) is unneccassary but does no harm.
|
|
if !filepath.IsAbs(oldpath) || !filepath.IsAbs(newpath) {
|
|
oldWd, err := os.Getwd()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer os.Chdir(oldWd)
|
|
}
|
|
// Make oldpath absolute
|
|
oldpath, err = dirfdAbs(olddirfd, oldpath)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
// Make newpath absolute
|
|
newpath, err = dirfdAbs(newdirfd, newpath)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return syscall.Rename(oldpath, newpath)
|
|
}
|
|
|
|
// Poor man's Unlinkat
|
|
func Unlinkat(dirfd int, path string) (err error) {
|
|
chdirMutex.Lock()
|
|
defer chdirMutex.Unlock()
|
|
if !filepath.IsAbs(path) {
|
|
oldWd, err := os.Getwd()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer os.Chdir(oldWd)
|
|
}
|
|
path, err = dirfdAbs(dirfd, path)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return syscall.Unlink(path)
|
|
}
|
|
|
|
// Poor man's Mknodat
|
|
func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
|
|
chdirMutex.Lock()
|
|
defer chdirMutex.Unlock()
|
|
if !filepath.IsAbs(path) {
|
|
oldWd, err := os.Getwd()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer os.Chdir(oldWd)
|
|
}
|
|
path, err = dirfdAbs(dirfd, path)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return syscall.Mknod(path, mode, dev)
|
|
}
|
|
|
|
// dirfdAbs transforms the dirfd-relative "path" to an absolute one. If the
|
|
// path is not already absolute, this function will change the working
|
|
// directory. The caller has to chdir back.
|
|
func dirfdAbs(dirfd int, path string) (absPath string, err error) {
|
|
if filepath.IsAbs(path) {
|
|
return path, nil
|
|
}
|
|
err = syscall.Fchdir(dirfd)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
wd, err := os.Getwd()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
return filepath.Join(wd, path), nil
|
|
}
|