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 "llvm/Support/Errno.h"
12
13#include <fcntl.h>
14#include <unistd.h>
15
16using namespace lldb;
17using namespace lldb_private;
18
19namespace {
20
21Status fileLock(int fd, int cmd, int lock_type, const uint64_t start,
22                const uint64_t len) {
23  struct flock fl;
24
25  fl.l_type = lock_type;
26  fl.l_whence = SEEK_SET;
27  fl.l_start = start;
28  fl.l_len = len;
29  fl.l_pid = ::getpid();
30
31  Status error;
32  if (llvm::sys::RetryAfterSignal(-1, ::fcntl, fd, cmd, &fl) == -1)
33    error.SetErrorToErrno();
34
35  return error;
36}
37
38} // namespace
39
40LockFilePosix::LockFilePosix(int fd) : LockFileBase(fd) {}
41
42LockFilePosix::~LockFilePosix() { Unlock(); }
43
44Status LockFilePosix::DoWriteLock(const uint64_t start, const uint64_t len) {
45  return fileLock(m_fd, F_SETLKW, F_WRLCK, start, len);
46}
47
48Status LockFilePosix::DoTryWriteLock(const uint64_t start, const uint64_t len) {
49  return fileLock(m_fd, F_SETLK, F_WRLCK, start, len);
50}
51
52Status LockFilePosix::DoReadLock(const uint64_t start, const uint64_t len) {
53  return fileLock(m_fd, F_SETLKW, F_RDLCK, start, len);
54}
55
56Status LockFilePosix::DoTryReadLock(const uint64_t start, const uint64_t len) {
57  return fileLock(m_fd, F_SETLK, F_RDLCK, start, len);
58}
59
60Status LockFilePosix::DoUnlock() {
61  return fileLock(m_fd, F_SETLK, F_UNLCK, m_start, m_len);
62}
63