int shmGetImpl()

in cachelib/shm/SysVShmSegment.cpp [35:89]

• 52 lines of code
• 14 McCabe index (conditional complexity)

int shmGetImpl(key_t key, size_t size, int flags) {
  if (key == IPC_PRIVATE) {
    util::throwSystemError(EINVAL, "Cannot create private segment");
  }

  const int shmid = shmget(key, size, flags);

  if (shmid != kInvalidShmId) {
    return shmid;
  }

  switch (errno) {
  case EACCES:
  case EINVAL:
  case ENOSPC:
  case ENOMEM:
  case ENFILE:
    util::throwSystemError(
        errno,
        folly::sformat(
            "Failed to create segment with key {}, size {}, flags {}",
            key,
            size,
            flags));
    break;
  case ENOENT:
    if (!(flags & IPC_CREAT)) { // trying to attach
      util::throwSystemError(errno);
    } else {
      util::throwSystemError(errno, "Invalid errno");
    }
    break;
  case EEXIST:
    if (flags & (IPC_CREAT | IPC_EXCL)) { // trying to create
      util::throwSystemError(errno);
    } else {
      XDCHECK(false);
      util::throwSystemError(errno, "Invalid errno");
    }
    break;
  case EPERM:
#ifdef __linux__
    if (flags & SHM_HUGETLB) {
      util::throwSystemError(errno);
      break;
    }
#endif
    XDCHECK(false);
    util::throwSystemError(errno, "Invalid errno");
  default:
    XDCHECK(false);
    util::throwSystemError(errno, "Invalid errno");
  }
  return kInvalidShmId;
}