138 lines
3.6 KiB
Go
138 lines
3.6 KiB
Go
package syscallcompat
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import (
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"log"
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"runtime"
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"syscall"
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"golang.org/x/sys/unix"
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"github.com/hanwen/go-fuse/fuse"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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const (
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// O_DIRECT means oncached I/O on Linux. No direct equivalent on MacOS and defined
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// to zero there.
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O_DIRECT = 0
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// O_PATH is only defined on Linux
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O_PATH = 0
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// KAUTH_UID_NONE and KAUTH_GID_NONE are special values to
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// revert permissions to the process credentials.
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KAUTH_UID_NONE = ^uint32(0) - 100
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KAUTH_GID_NONE = ^uint32(0) - 100
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)
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// Unfortunately pthread_setugid_np does not have a syscall wrapper yet.
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func pthread_setugid_np(uid uint32, gid uint32) (err error) {
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_, _, e1 := syscall.RawSyscall(syscall.SYS_SETTID, uintptr(uid), uintptr(gid), 0)
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if e1 != 0 {
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err = e1
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}
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return
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}
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// Sorry, fallocate is not available on OSX at all and
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// fcntl F_PREALLOCATE is not accessible from Go.
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// See https://github.com/rfjakob/gocryptfs/issues/18 if you want to help.
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func EnospcPrealloc(fd int, off int64, len int64) error {
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return nil
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}
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// See above.
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func Fallocate(fd int, mode uint32, off int64, len int64) error {
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return syscall.EOPNOTSUPP
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}
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// Dup3 is not available on Darwin, so we use Dup2 instead.
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func Dup3(oldfd int, newfd int, flags int) (err error) {
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if flags != 0 {
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log.Panic("darwin does not support dup3 flags")
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}
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return syscall.Dup2(oldfd, newfd)
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}
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////////////////////////////////////////////////////////
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//// Emulated Syscalls (see emulate.go) ////////////////
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////////////////////////////////////////////////////////
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func OpenatUser(dirfd int, path string, flags int, mode uint32, context *fuse.Context) (fd int, err error) {
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if context != nil {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
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if err != nil {
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return -1, err
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}
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defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
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}
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return Openat(dirfd, path, flags, mode)
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}
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func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
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return emulateMknodat(dirfd, path, mode, dev)
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}
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func MknodatUser(dirfd int, path string, mode uint32, dev int, context *fuse.Context) (err error) {
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if context != nil {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
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if err != nil {
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return err
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}
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defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
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}
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return Mknodat(dirfd, path, mode, dev)
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}
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func Fchmodat(dirfd int, path string, mode uint32, flags int) (err error) {
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// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
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if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
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tlog.Warn.Printf("Fchmodat: adding missing AT_SYMLINK_NOFOLLOW flag")
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flags |= unix.AT_SYMLINK_NOFOLLOW
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}
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return unix.Fchmodat(dirfd, path, mode, flags)
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}
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func SymlinkatUser(oldpath string, newdirfd int, newpath string, context *fuse.Context) (err error) {
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if context != nil {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
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if err != nil {
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return err
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}
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defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
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}
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return Symlinkat(oldpath, newdirfd, newpath)
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}
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func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (err error) {
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if context != nil {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
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if err != nil {
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return err
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}
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defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
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}
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return Mkdirat(dirfd, path, mode)
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}
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func Getdents(fd int) ([]fuse.DirEntry, error) {
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return emulateGetdents(fd)
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}
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