Add CloseMultipleNowOrOnExec()

util/test/posix/close_multiple.h

Index: util/test/posix/close_multiple.h
diff --git a/util/test/posix/close_multiple.h b/util/test/posix/close_multiple.h
new file mode 100644
index 0000000000000000000000000000000000000000..f0199c16ef1191d754fd29d3fd541d96f7133f82
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+++ b/util/test/posix/close_multiple.h
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+// 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.
+void CloseMultipleNowOrOnExec(int fd);
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_UTIL_TEST_POSIX_CLOSE_MULTIPLE_H_