1 //===-- LockFilePosix.cpp ---------------------------------------*- C++ -*-===//
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/posix/LockFilePosix.h"
10 
11 #include <fcntl.h>
12 #include <unistd.h>
13 
14 using namespace lldb;
15 using namespace lldb_private;
16 
17 namespace {
18 
19 Status fileLock(int fd, int cmd, int lock_type, const uint64_t start,
20                 const uint64_t len) {
21   struct flock fl;
22 
23   fl.l_type = lock_type;
24   fl.l_whence = SEEK_SET;
25   fl.l_start = start;
26   fl.l_len = len;
27   fl.l_pid = ::getpid();
28 
29   Status error;
30   if (::fcntl(fd, cmd, &fl) == -1)
31     error.SetErrorToErrno();
32 
33   return error;
34 }
35 
36 } // namespace
37 
38 LockFilePosix::LockFilePosix(int fd) : LockFileBase(fd) {}
39 
40 LockFilePosix::~LockFilePosix() { Unlock(); }
41 
42 Status LockFilePosix::DoWriteLock(const uint64_t start, const uint64_t len) {
43   return fileLock(m_fd, F_SETLKW, F_WRLCK, start, len);
44 }
45 
46 Status LockFilePosix::DoTryWriteLock(const uint64_t start, const uint64_t len) {
47   return fileLock(m_fd, F_SETLK, F_WRLCK, start, len);
48 }
49 
50 Status LockFilePosix::DoReadLock(const uint64_t start, const uint64_t len) {
51   return fileLock(m_fd, F_SETLKW, F_RDLCK, start, len);
52 }
53 
54 Status LockFilePosix::DoTryReadLock(const uint64_t start, const uint64_t len) {
55   return fileLock(m_fd, F_SETLK, F_RDLCK, start, len);
56 }
57 
58 Status LockFilePosix::DoUnlock() {
59   return fileLock(m_fd, F_SETLK, F_UNLCK, m_start, m_len);
60 }
61