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package syscallcompat
import (
"log"
"runtime"
"syscall"
"golang.org/x/sys/unix"
"github.com/hanwen/go-fuse/fuse"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
const (
// O_DIRECT means oncached I/O on Linux. No direct equivalent on MacOS and defined
// to zero there.
O_DIRECT = 0
// O_PATH is only defined on Linux
O_PATH = 0
// KAUTH_UID_NONE and KAUTH_GID_NONE are special values to
// revert permissions to the process credentials.
KAUTH_UID_NONE = ^uint32(0) - 100
KAUTH_GID_NONE = ^uint32(0) - 100
)
// Unfortunately pthread_setugid_np does not have a syscall wrapper yet.
func pthread_setugid_np(uid uint32, gid uint32) (err error) {
_, _, e1 := syscall.RawSyscall(syscall.SYS_SETTID, uintptr(uid), uintptr(gid), 0)
if e1 != 0 {
err = e1
}
return
}
// 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) error {
return nil
}
// See above.
func Fallocate(fd int, mode uint32, off int64, len int64) error {
return syscall.EOPNOTSUPP
}
// Dup3 is not available on Darwin, so we use Dup2 instead.
func Dup3(oldfd int, newfd int, flags int) (err error) {
if flags != 0 {
log.Panic("darwin does not support dup3 flags")
}
return syscall.Dup2(oldfd, newfd)
}
////////////////////////////////////////////////////////
//// Emulated Syscalls (see emulate.go) ////////////////
////////////////////////////////////////////////////////
func OpenatUser(dirfd int, path string, flags int, mode uint32, context *fuse.Context) (fd int, err error) {
if context != nil {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
if err != nil {
return -1, err
}
defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
}
return Openat(dirfd, path, flags, mode)
}
func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
return emulateMknodat(dirfd, path, mode, dev)
}
func MknodatUser(dirfd int, path string, mode uint32, dev int, context *fuse.Context) (err error) {
if context != nil {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
if err != nil {
return err
}
defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
}
return Mknodat(dirfd, path, mode, dev)
}
func Fchmodat(dirfd int, path string, mode uint32, flags int) (err error) {
// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
tlog.Warn.Printf("Fchmodat: adding missing AT_SYMLINK_NOFOLLOW flag")
flags |= unix.AT_SYMLINK_NOFOLLOW
}
return unix.Fchmodat(dirfd, path, mode, flags)
}
func Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error) {
return emulateFchownat(dirfd, path, uid, gid, flags)
}
func Symlinkat(oldpath string, newdirfd int, newpath string) (err error) {
return emulateSymlinkat(oldpath, newdirfd, newpath)
}
func SymlinkatUser(oldpath string, newdirfd int, newpath string, context *fuse.Context) (err error) {
if context != nil {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
if err != nil {
return err
}
defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
}
return Symlinkat(oldpath, newdirfd, newpath)
}
func Mkdirat(dirfd int, path string, mode uint32) (err error) {
return emulateMkdirat(dirfd, path, mode)
}
func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (err error) {
if context != nil {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
if err != nil {
return err
}
defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
}
return Mkdirat(dirfd, path, mode)
}
func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
return emulateFstatat(dirfd, path, stat, flags)
}
func Getdents(fd int) ([]fuse.DirEntry, error) {
return emulateGetdents(fd)
}
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