/*
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* Copyright (c) 2017 Facebook, Inc.
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* Copyright (c) 2017 VMware, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <memory>
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#include <sys/types.h>
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#include "file_desc.h"
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class ProcMountNSGuard;
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// ProcMountNS opens an fd corresponding to the current mount namespace and the
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// mount namespace of the target process.
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// The fds will remain uninitialized (<0) if the open fails, or if the current
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// and target namespaces are identical.
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class ProcMountNS {
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public:
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explicit ProcMountNS(int pid);
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int self() const { return self_fd_; }
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int target() const { return target_fd_; }
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ino_t target_ino() const { return target_ino_; }
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private:
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ebpf::FileDesc self_fd_;
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ebpf::FileDesc target_fd_;
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ino_t target_ino_;
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};
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// ProcMountNSGuard switches to the target mount namespace and restores the
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// original upon going out of scope.
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class ProcMountNSGuard {
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public:
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explicit ProcMountNSGuard(ProcMountNS *mount_ns);
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explicit ProcMountNSGuard(int pid);
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~ProcMountNSGuard();
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private:
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void init();
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std::unique_ptr<ProcMountNS> mount_ns_instance_;
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ProcMountNS *mount_ns_;
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bool entered_;
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};
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