libgocryptfs/internal/syscallcompat/emulate.go
Sebastian Lackner 0345cc0830 syscallcompat: Drop Fchmodat emulation on macOS.
On macOS the function has a flags argument, so we don't need the
/proc/self/fd trick used on Linux.
2019-01-14 21:27:28 +01:00

112 lines
2.6 KiB
Go

package syscallcompat
import (
"path/filepath"
"sync"
"syscall"
"golang.org/x/sys/unix"
)
var chdirMutex sync.Mutex
// emulateMknodat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateMknodat(dirfd int, path string, mode uint32, dev int) error {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(dirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return syscall.Mknod(path, mode, dev)
}
// emulateFchownat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateFchownat(dirfd int, path string, uid int, gid int, flags int) (err error) {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(dirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return syscall.Lchown(path, uid, gid)
}
// emulateSymlinkat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateSymlinkat(oldpath string, newdirfd int, newpath string) (err error) {
if !filepath.IsAbs(newpath) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(newdirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return syscall.Symlink(oldpath, newpath)
}
// emulateMkdirat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateMkdirat(dirfd int, path string, mode uint32) (err error) {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(dirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return syscall.Mkdir(path, mode)
}
// emulateFstatat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateFstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(dirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return unix.Lstat(path, stat)
}