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package syscallcompat
import (
"log"
"path/filepath"
"runtime"
"syscall"
"time"
"unsafe"
"golang.org/x/sys/unix"
"github.com/hanwen/go-fuse/v2/fuse"
)
const (
// O_DIRECT means uncached 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
// Only defined on Linux
RENAME_NOREPLACE = 0
RENAME_WHITEOUT = 0
RENAME_EXCHANGE = 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
}
// Unfortunately fsetattrlist does not have a syscall wrapper yet.
func fsetattrlist(fd int, list unsafe.Pointer, buf unsafe.Pointer, size uintptr, options int) (err error) {
_, _, e1 := syscall.Syscall6(syscall.SYS_FSETATTRLIST, uintptr(fd), uintptr(list), uintptr(buf), uintptr(size), uintptr(options), 0)
if e1 != 0 {
err = e1
}
return
}
// Setattrlist already has a syscall wrapper, but it is not exported.
func setattrlist(path *byte, list unsafe.Pointer, buf unsafe.Pointer, size uintptr, options int) (err error) {
_, _, e1 := syscall.Syscall6(syscall.SYS_SETATTRLIST, uintptr(unsafe.Pointer(path)), uintptr(list), uintptr(buf), uintptr(size), uintptr(options), 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 FchmodatNofollow(dirfd int, path string, mode uint32) (err error) {
return unix.Fchmodat(dirfd, path, mode, unix.AT_SYMLINK_NOFOLLOW)
}
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 unix.Symlinkat(oldpath, newdirfd, newpath)
}
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 unix.Mkdirat(dirfd, path, mode)
}
type attrList struct {
bitmapCount uint16
_ uint16
CommonAttr uint32
VolAttr uint32
DirAttr uint32
FileAttr uint32
Forkattr uint32
}
func timesToAttrList(a *time.Time, m *time.Time) (attrList attrList, attributes [2]unix.Timespec) {
attrList.bitmapCount = unix.ATTR_BIT_MAP_COUNT
attrList.CommonAttr = 0
i := 0
if m != nil {
attributes[i] = unix.Timespec(fuse.UtimeToTimespec(m))
attrList.CommonAttr |= unix.ATTR_CMN_MODTIME
i += 1
}
if a != nil {
attributes[i] = unix.Timespec(fuse.UtimeToTimespec(a))
attrList.CommonAttr |= unix.ATTR_CMN_ACCTIME
i += 1
}
return attrList, attributes
}
// FutimesNano syscall.
func FutimesNano(fd int, a *time.Time, m *time.Time) (err error) {
attrList, attributes := timesToAttrList(a, m)
return fsetattrlist(fd, unsafe.Pointer(&attrList), unsafe.Pointer(&attributes),
unsafe.Sizeof(attributes), 0)
}
// UtimesNanoAtNofollow is like UtimesNanoAt but never follows symlinks.
//
// Unfortunately we cannot use unix.UtimesNanoAt since it is broken and just
// ignores the provided 'dirfd'. In addition, it also lacks handling of 'nil'
// pointers (used to preserve one of both timestamps).
func UtimesNanoAtNofollow(dirfd int, path string, a *time.Time, m *time.Time) (err error) {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
var cwd int
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)
}
_p0, err := syscall.BytePtrFromString(path)
if err != nil {
return err
}
attrList, attributes := timesToAttrList(a, m)
return setattrlist(_p0, unsafe.Pointer(&attrList), unsafe.Pointer(&attributes),
unsafe.Sizeof(attributes), unix.FSOPT_NOFOLLOW)
}
func Getdents(fd int) ([]fuse.DirEntry, error) {
entries, _, err := emulateGetdents(fd)
return entries, err
}
func GetdentsSpecial(fd int) (entries []fuse.DirEntry, entriesSpecial []fuse.DirEntry, err error) {
return emulateGetdents(fd)
}
// Renameat2 does not exist on Darwin, so we call Renameat and ignore the flags.
func Renameat2(olddirfd int, oldpath string, newdirfd int, newpath string, flags uint) (err error) {
return unix.Renameat(olddirfd, oldpath, newdirfd, newpath)
}
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