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   Status error;
  30   if (llvm::sys::RetryAfterSignal(-1, ::fcntl, fd, cmd, &fl) == -1)
  31     error.SetErrorToErrno();
  32
  33   return error;
  34 }
  35
  36 LockFilePosix::LockFilePosix(int fd) : LockFileBase(fd) {}
  37
  38 LockFilePosix::~LockFilePosix() { Unlock(); }
  39
  40 Status LockFilePosix::DoWriteLock(const uint64_t start, const uint64_t len) {
  41   return fileLock(m_fd, F_SETLKW, F_WRLCK, start, len);
  42 }
  43
  44 Status LockFilePosix::DoTryWriteLock(const uint64_t start, const uint64_t len) {
  45   return fileLock(m_fd, F_SETLK, F_WRLCK, start, len);
  46 }
  47
  48 Status LockFilePosix::DoReadLock(const uint64_t start, const uint64_t len) {
  49   return fileLock(m_fd, F_SETLKW, F_RDLCK, start, len);
  50 }
  51
  52 Status LockFilePosix::DoTryReadLock(const uint64_t start, const uint64_t len) {
  53   return fileLock(m_fd, F_SETLK, F_RDLCK, start, len);
  54 }
  55
  56 Status LockFilePosix::DoUnlock() {
  57   return fileLock(m_fd, F_SETLK, F_UNLCK, m_start, m_len);
  58 }