1 //===-- LockFileWindows.cpp -------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "lldb/Host/windows/LockFileWindows.h"
11 
12 #include <io.h>
13 
14 using namespace lldb;
15 using namespace lldb_private;
16 
17 namespace
18 {
19 
20 Error fileLock (HANDLE file_handle, DWORD flags, const uint64_t start, const uint64_t len)
21 {
22     if (start != 0)
23         return Error ("Non-zero start lock regions are not supported");
24 
25     OVERLAPPED overlapped = {0};
26 
27     if (!::LockFileEx (file_handle, flags, 0, len, 0, &overlapped) && ::GetLastError () != ERROR_IO_PENDING)
28         return Error (::GetLastError (), eErrorTypeWin32);
29 
30     DWORD bytes;
31     if (!::GetOverlappedResult (file_handle, &overlapped, &bytes, TRUE))
32         return Error (::GetLastError (), eErrorTypeWin32);
33 
34     return Error ();
35 }
36 
37 }  // namespace
38 
39 LockFileWindows::LockFileWindows (int fd)
40     : LockFileBase (fd),
41       m_file (reinterpret_cast<HANDLE> (_get_osfhandle (fd)))
42 {
43 }
44 
45 LockFileWindows::~LockFileWindows ()
46 {
47     Unlock ();
48     if (m_file != INVALID_HANDLE_VALUE)
49     {
50         ::CloseHandle (m_file);
51         m_file = INVALID_HANDLE_VALUE;
52     }
53 }
54 
55 bool
56 LockFileWindows::IsValidFile () const
57 {
58     return LockFileBase::IsValidFile() && m_file != INVALID_HANDLE_VALUE;
59 }
60 
61 Error
62 LockFileWindows::DoWriteLock (const uint64_t start, const uint64_t len)
63 {
64     return fileLock (m_file, LOCKFILE_EXCLUSIVE_LOCK, start, len);
65 }
66 
67 Error
68 LockFileWindows::DoTryWriteLock (const uint64_t start, const uint64_t len)
69 {
70     return fileLock (m_file, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY, start, len);
71 }
72 
73 Error
74 LockFileWindows::DoReadLock (const uint64_t start, const uint64_t len)
75 {
76     return fileLock (m_file, 0, start, len);
77 }
78 
79 Error
80 LockFileWindows::DoTryReadLock (const uint64_t start, const uint64_t len)
81 {
82     return fileLock (m_file, LOCKFILE_FAIL_IMMEDIATELY, start, len);
83 }
84 
85 Error
86 LockFileWindows::DoUnlock ()
87 {
88     OVERLAPPED overlapped = {0};
89 
90     if (!::UnlockFileEx (m_file, 0, m_len, 0, &overlapped) && ::GetLastError () != ERROR_IO_PENDING)
91         return Error (::GetLastError (), eErrorTypeWin32);
92 
93     DWORD bytes;
94     if (!::GetOverlappedResult (m_file, &overlapped, &bytes, TRUE))
95         return Error (::GetLastError (), eErrorTypeWin32);
96 
97     return Error ();
98 }
99