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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef SANDBOX_LINUX_SERVICES_PROC_UTIL_H_
#define SANDBOX_LINUX_SERVICES_PROC_UTIL_H_
#include "base/files/scoped_file.h"
#include "sandbox/sandbox_export.h"
namespace sandbox {
class SANDBOX_EXPORT ProcUtil {
public:
ProcUtil() = delete;
ProcUtil(const ProcUtil&) = delete;
ProcUtil& operator=(const ProcUtil&) = delete;
// Returns the number of file descriptors in the current process's FD
// table, excluding |proc_fd|, which should be a file descriptor for
// /proc/.
static int CountOpenFds(int proc_fd);
// Checks whether the current process has any directory file descriptor open.
// Directory file descriptors are "capabilities" that would let a process use
// system calls such as openat() to bypass restrictions such as
// DropFileSystemAccess().
// Sometimes it's useful to call HasOpenDirectory() after file system access
// has been dropped. In this case, |proc_fd| should be a file descriptor to
// /proc/. The file descriptor in |proc_fd| will be ignored by
// HasOpenDirectory() and remains owned by the caller. It is very important
// for the caller to close it.
[[nodiscard]] static bool HasOpenDirectory(int proc_fd);
[[nodiscard]] static bool HasOpenDirectory();
// Open /proc/ or crash if not possible.
static base::ScopedFD OpenProc();
};
} // namespace sandbox
#endif // SANDBOX_LINUX_SERVICES_PROC_UTIL_H_
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