1//===-- LockFileWindows.cpp -----------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Host/windows/LockFileWindows.h"
10
11#include <io.h>
12
13using namespace lldb;
14using namespace lldb_private;
15
16static Status fileLock(HANDLE file_handle, DWORD flags, const uint64_t start,
17                       const uint64_t len) {
18  if (start != 0)
19    return Status("Non-zero start lock regions are not supported");
20
21  OVERLAPPED overlapped = {};
22
23  if (!::LockFileEx(file_handle, flags, 0, len, 0, &overlapped) &&
24      ::GetLastError() != ERROR_IO_PENDING)
25    return Status(::GetLastError(), eErrorTypeWin32);
26
27  DWORD bytes;
28  if (!::GetOverlappedResult(file_handle, &overlapped, &bytes, TRUE))
29    return Status(::GetLastError(), eErrorTypeWin32);
30
31  return Status();
32}
33
34LockFileWindows::LockFileWindows(int fd)
35    : LockFileBase(fd), m_file(reinterpret_cast<HANDLE>(_get_osfhandle(fd))) {}
36
37LockFileWindows::~LockFileWindows() { Unlock(); }
38
39bool LockFileWindows::IsValidFile() const {
40  return LockFileBase::IsValidFile() && m_file != INVALID_HANDLE_VALUE;
41}
42
43Status LockFileWindows::DoWriteLock(const uint64_t start, const uint64_t len) {
44  return fileLock(m_file, LOCKFILE_EXCLUSIVE_LOCK, start, len);
45}
46
47Status LockFileWindows::DoTryWriteLock(const uint64_t start,
48                                       const uint64_t len) {
49  return fileLock(m_file, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY,
50                  start, len);
51}
52
53Status LockFileWindows::DoReadLock(const uint64_t start, const uint64_t len) {
54  return fileLock(m_file, 0, start, len);
55}
56
57Status LockFileWindows::DoTryReadLock(const uint64_t start,
58                                      const uint64_t len) {
59  return fileLock(m_file, LOCKFILE_FAIL_IMMEDIATELY, start, len);
60}
61
62Status LockFileWindows::DoUnlock() {
63  OVERLAPPED overlapped = {};
64
65  if (!::UnlockFileEx(m_file, 0, m_len, 0, &overlapped) &&
66      ::GetLastError() != ERROR_IO_PENDING)
67    return Status(::GetLastError(), eErrorTypeWin32);
68
69  DWORD bytes;
70  if (!::GetOverlappedResult(m_file, &overlapped, &bytes, TRUE))
71    return Status(::GetLastError(), eErrorTypeWin32);
72
73  return Status();
74}
75