CloseMultipleNowOrOnExec(): promote out of test

util/test/posix/close_multiple.h

-// Copyright 2014 The Crashpad Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef CRASHPAD_UTIL_TEST_POSIX_CLOSE_MULTIPLE_H_
-#define CRASHPAD_UTIL_TEST_POSIX_CLOSE_MULTIPLE_H_
-
-namespace crashpad {
-
-//! \brief Close multiple file descriptors or mark them close-on-exec.
-//!
-//! This is similar to the BSD/Solaris-style `closefrom()` routine, which closes
-//! all open file descriptors equal to or higher than its \a fd argument. This
-//! function must not be called while other threads are active. It is intended
-//! to be used in a child process created by `fork()`, prior to calling an
-//! `exec()`-family function. This guarantees that a (possibly untrustworthy)
-//! child process does not inherit file descriptors that it has no need for.
-//!
-//! Unlike the BSD function, this function may not close file descriptors
-//! immediately, but may instead mark them as close-on-exec. The actual behavior
-//! chosen is specific to the operating system. On Mac OS X, file descriptors
-//! are marked close-on-exec instead of being closed outright in order to avoid
-//! raising `EXC_GUARD` exceptions for guarded file descriptors that are
-//! protected against `close()`.
-//!
-//! \param[in] fd The lowest file descriptor to close or set as close-on-exec.
-//! \param[in] preserve_fd A file descriptor to preserve and not close (or set
-//!     as close-on-exec), even if it is open and its value is greater than \a
-//!     fd. To not preserve any file descriptor, pass `-1` for this parameter.
-void CloseMultipleNowOrOnExec(int fd, int preserve_fd);
-
-}  // namespace crashpad
-
-#endif  // CRASHPAD_UTIL_TEST_POSIX_CLOSE_MULTIPLE_H_