1 //===-- LockFilePosix.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/posix/LockFilePosix.h"
11 
12 #include <fcntl.h>
13 #include <unistd.h>
14 
15 using namespace lldb;
16 using namespace lldb_private;
17 
18 namespace {
19 
20 Status fileLock(int fd, int cmd, int lock_type, const uint64_t start,
21                 const uint64_t len) {
22   struct flock fl;
23 
24   fl.l_type = lock_type;
25   fl.l_whence = SEEK_SET;
26   fl.l_start = start;
27   fl.l_len = len;
28   fl.l_pid = ::getpid();
29 
30   Status error;
31   if (::fcntl(fd, cmd, &fl) == -1)
32     error.SetErrorToErrno();
33 
34   return error;
35 }
36 
37 } // namespace
38 
39 LockFilePosix::LockFilePosix(int fd) : LockFileBase(fd) {}
40 
41 LockFilePosix::~LockFilePosix() { Unlock(); }
42 
43 Status LockFilePosix::DoWriteLock(const uint64_t start, const uint64_t len) {
44   return fileLock(m_fd, F_SETLKW, F_WRLCK, start, len);
45 }
46 
47 Status LockFilePosix::DoTryWriteLock(const uint64_t start, const uint64_t len) {
48   return fileLock(m_fd, F_SETLK, F_WRLCK, start, len);
49 }
50 
51 Status LockFilePosix::DoReadLock(const uint64_t start, const uint64_t len) {
52   return fileLock(m_fd, F_SETLKW, F_RDLCK, start, len);
53 }
54 
55 Status LockFilePosix::DoTryReadLock(const uint64_t start, const uint64_t len) {
56   return fileLock(m_fd, F_SETLK, F_RDLCK, start, len);
57 }
58 
59 Status LockFilePosix::DoUnlock() {
60   return fileLock(m_fd, F_SETLK, F_UNLCK, m_start, m_len);
61 }
62