libgocryptfs/internal/syscallcompat/sys_linux.go
Jakob Unterwurzacher 53f7e1a0f0 macos: fix O_DIRECT build failure
O_DIRECT has no direct equivalent on MacOS
(check out https://github.com/libuv/libuv/issues/1600 for details).

Just define it to zero there.
2018-07-04 09:04:00 +02:00

129 lines
4.1 KiB
Go

// Package syscallcompat wraps Linux-specific syscalls.
package syscallcompat
import (
"sync"
"syscall"
"golang.org/x/sys/unix"
"github.com/hanwen/go-fuse/fuse"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
const _FALLOC_FL_KEEP_SIZE = 0x01
// O_DIRECT means oncached I/O on Linux. No direct equivalent on MacOS and defined
// to zero there.
const O_DIRECT = syscall.O_DIRECT
var preallocWarn sync.Once
// EnospcPrealloc preallocates ciphertext space without changing the file
// size. This guarantees that we don't run out of space while writing a
// ciphertext block (that would corrupt the block).
func EnospcPrealloc(fd int, off int64, len int64) (err error) {
for {
err = syscall.Fallocate(fd, _FALLOC_FL_KEEP_SIZE, off, len)
if err == syscall.EINTR {
// fallocate, like many syscalls, can return EINTR. This is not an
// error and just signifies that the operation was interrupted by a
// signal and we should try again.
continue
}
if err == syscall.EOPNOTSUPP {
// ZFS and ext3 do not support fallocate. Warn but continue anyway.
// https://github.com/rfjakob/gocryptfs/issues/22
preallocWarn.Do(func() {
tlog.Warn.Printf("Warning: The underlying filesystem " +
"does not support fallocate(2). gocryptfs will continue working " +
"but is no longer resistant against out-of-space errors.\n")
})
return nil
}
return err
}
}
// Fallocate wraps the Fallocate syscall.
func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
return syscall.Fallocate(fd, mode, off, len)
}
// Openat wraps the Openat syscall.
func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
// Why would we ever want to call this without O_NOFOLLOW and O_EXCL?
if !(flags&syscall.O_CREAT != 0 && flags&syscall.O_EXCL != 0) && flags&syscall.O_NOFOLLOW == 0 {
tlog.Warn.Printf("Openat: adding missing O_NOFOLLOW flag")
flags |= syscall.O_NOFOLLOW
}
return syscall.Openat(dirfd, path, flags, mode)
}
// Renameat wraps the Renameat syscall.
func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
return syscall.Renameat(olddirfd, oldpath, newdirfd, newpath)
}
// Unlinkat syscall.
func Unlinkat(dirfd int, path string, flags int) (err error) {
return unix.Unlinkat(dirfd, path, flags)
}
// Mknodat wraps the Mknodat syscall.
func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
return syscall.Mknodat(dirfd, path, mode, dev)
}
// Dup3 wraps the Dup3 syscall. We want to use Dup3 rather than Dup2 because Dup2
// is not implemented on arm64.
func Dup3(oldfd int, newfd int, flags int) (err error) {
return syscall.Dup3(oldfd, newfd, flags)
}
// Fchmodat syscall.
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 syscall.Fchmodat(dirfd, path, mode, flags)
}
// Fchownat syscall.
func Fchownat(dirfd int, path string, uid int, gid int, 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("Fchownat: adding missing AT_SYMLINK_NOFOLLOW flag")
flags |= unix.AT_SYMLINK_NOFOLLOW
}
return syscall.Fchownat(dirfd, path, uid, gid, flags)
}
// Symlinkat syscall.
func Symlinkat(oldpath string, newdirfd int, newpath string) (err error) {
return unix.Symlinkat(oldpath, newdirfd, newpath)
}
// Mkdirat syscall.
func Mkdirat(dirfd int, path string, mode uint32) (err error) {
return syscall.Mkdirat(dirfd, path, mode)
}
// Fstatat syscall.
func Fstatat(dirfd int, path string, stat *unix.Stat_t, 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("Fstatat: adding missing AT_SYMLINK_NOFOLLOW flag")
flags |= unix.AT_SYMLINK_NOFOLLOW
}
return unix.Fstatat(dirfd, path, stat, flags)
}
// Getdents syscall.
func Getdents(fd int) ([]fuse.DirEntry, error) {
return getdents(fd)
}