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|
//go:build !sqlite3_flock
package vfs
import (
"io"
"os"
"runtime"
"time"
"golang.org/x/sys/unix"
)
const (
// https://github.com/apple/darwin-xnu/blob/main/bsd/sys/fcntl.h
_F_OFD_SETLK = 90
_F_OFD_SETLKW = 91
_F_OFD_SETLKWTIMEOUT = 93
)
type flocktimeout_t struct {
fl unix.Flock_t
timeout unix.Timespec
}
func osSync(file *os.File, open OpenFlag, sync SyncFlag) error {
var cmd int
if sync&SYNC_FULL == SYNC_FULL {
// For rollback journals all we really need is a barrier.
if open&OPEN_MAIN_JOURNAL != 0 {
cmd = unix.F_BARRIERFSYNC
} else {
cmd = unix.F_FULLFSYNC
}
}
fd := file.Fd()
for {
err := error(unix.ENOTSUP)
if cmd != 0 {
_, err = unix.FcntlInt(fd, cmd, 0)
}
if err == unix.ENOTSUP {
err = unix.Fsync(int(fd))
}
if err != unix.EINTR {
return err
}
}
}
func osAllocate(file *os.File, size int64) error {
off, err := file.Seek(0, io.SeekEnd)
if err != nil {
return err
}
if size <= off {
return nil
}
store := unix.Fstore_t{
Flags: unix.F_ALLOCATEALL | unix.F_ALLOCATECONTIG,
Posmode: unix.F_PEOFPOSMODE,
Offset: 0,
Length: size - off,
}
// Try to get a continuous chunk of disk space.
err = unix.FcntlFstore(file.Fd(), unix.F_PREALLOCATE, &store)
if err != nil {
// OK, perhaps we are too fragmented, allocate non-continuous.
store.Flags = unix.F_ALLOCATEALL
unix.FcntlFstore(file.Fd(), unix.F_PREALLOCATE, &store)
}
return file.Truncate(size)
}
func osReadLock(file *os.File, start, len int64, timeout time.Duration) error {
return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
}
func osWriteLock(file *os.File, start, len int64, timeout time.Duration) error {
return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
}
func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) error {
lock := &flocktimeout_t{fl: unix.Flock_t{
Type: typ,
Start: start,
Len: len,
}}
var err error
switch {
case timeout == 0:
err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &lock.fl)
case timeout < 0:
err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLKW, &lock.fl)
default:
lock.timeout = unix.NsecToTimespec(int64(timeout / time.Nanosecond))
err = unix.FcntlFlock(file.Fd(), _F_OFD_SETLKWTIMEOUT, &lock.fl)
runtime.KeepAlive(lock)
}
return osLockErrorCode(err, def)
}
func osUnlock(file *os.File, start, len int64) error {
lock := unix.Flock_t{
Type: unix.F_UNLCK,
Start: start,
Len: len,
}
for {
err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &lock)
if err == nil {
return nil
}
if err != unix.EINTR {
return sysError{err, _IOERR_UNLOCK}
}
}
}
|
