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 exists on Linux. Define here to fix build failure, even though // we will never see the flags. RENAME_NOREPLACE = 1 RENAME_EXCHANGE = 2 RENAME_WHITEOUT = 4 // F_OFD_SETLKW only exists on Linux. On Darwin, fall back to F_SETLKW as a // flawed replacement. F_OFD_SETLKW = unix.F_SETLKW // 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) }