1//go:build !sqlite3_flock
 2
 3package vfs
 4
 5import (
 6	"io"
 7	"os"
 8	"time"
 9
10	"golang.org/x/sys/unix"
11)
12
13func osSync(file *os.File, _ /*fullsync*/, _ /*dataonly*/ bool) error {
14	// SQLite trusts Linux's fdatasync for all fsync's.
15	for {
16		err := unix.Fdatasync(int(file.Fd()))
17		if err != unix.EINTR {
18			return err
19		}
20	}
21}
22
23func osAllocate(file *os.File, size int64) error {
24	if size == 0 {
25		return nil
26	}
27	for {
28		err := unix.Fallocate(int(file.Fd()), 0, 0, size)
29		if err == unix.EOPNOTSUPP {
30			break
31		}
32		if err != unix.EINTR {
33			return err
34		}
35	}
36	off, err := file.Seek(0, io.SeekEnd)
37	if err != nil {
38		return err
39	}
40	if size <= off {
41		return nil
42	}
43	return file.Truncate(size)
44
45}
46
47func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
48	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
49}
50
51func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
52	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
53}
54
55func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
56	lock := unix.Flock_t{
57		Type:  typ,
58		Start: start,
59		Len:   len,
60	}
61	var err error
62	switch {
63	default:
64		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
65	case timeout < 0:
66		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLKW, &lock)
67	}
68	return osLockErrorCode(err, def)
69}
70
71func osUnlock(file *os.File, start, len int64) _ErrorCode {
72	lock := unix.Flock_t{
73		Type:  unix.F_UNLCK,
74		Start: start,
75		Len:   len,
76	}
77	for {
78		err := unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
79		if err == nil {
80			return _OK
81		}
82		if err != unix.EINTR {
83			return _IOERR_UNLOCK
84		}
85	}
86}