lldb/source/Host/posix/LockFilePosix.cpp

   1 //===-- LockFilePosix.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/posix/LockFilePosix.h"
  10
  11 #include "llvm/Support/Errno.h"
  12
  13 #include <fcntl.h>
  14 #include <unistd.h>
  15
  16 using namespace lldb;
  17 using namespace lldb_private;
  18
  19 static 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   if (llvm::sys::RetryAfterSignal(-1, ::fcntl, fd, cmd, &fl) == -1)
  30     return Status::FromErrno();
  31
  32   return Status();
  33 }
  34
  35 LockFilePosix::LockFilePosix(int fd) : LockFileBase(fd) {}
  36
  37 LockFilePosix::~LockFilePosix() { Unlock(); }
  38
  39 Status LockFilePosix::DoWriteLock(const uint64_t start, const uint64_t len) {
  40   return fileLock(m_fd, F_SETLKW, F_WRLCK, start, len);
  41 }
  42
  43 Status LockFilePosix::DoTryWriteLock(const uint64_t start, const uint64_t len) {
  44   return fileLock(m_fd, F_SETLK, F_WRLCK, start, len);
  45 }
  46
  47 Status LockFilePosix::DoReadLock(const uint64_t start, const uint64_t len) {
  48   return fileLock(m_fd, F_SETLKW, F_RDLCK, start, len);
  49 }
  50
  51 Status LockFilePosix::DoTryReadLock(const uint64_t start, const uint64_t len) {
  52   return fileLock(m_fd, F_SETLK, F_RDLCK, start, len);
  53 }
  54
  55 Status LockFilePosix::DoUnlock() {
  56   return fileLock(m_fd, F_SETLK, F_UNLCK, m_start, m_len);
  57 }