1 /* 2 * Copyright (c) 2017 Facebook, Inc. 3 * Copyright (c) 2017 VMware, Inc. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #pragma once 19 20 #include <memory> 21 #include <sys/types.h> 22 23 #include "file_desc.h" 24 25 class ProcMountNSGuard; 26 27 // ProcMountNS opens an fd corresponding to the current mount namespace and the 28 // mount namespace of the target process. 29 // The fds will remain uninitialized (<0) if the open fails, or if the current 30 // and target namespaces are identical. 31 class ProcMountNS { 32 public: 33 explicit ProcMountNS(int pid); 34 int self() const { return self_fd_; } 35 int target() const { return target_fd_; } 36 ino_t target_ino() const { return target_ino_; } 37 38 private: 39 ebpf::FileDesc self_fd_; 40 ebpf::FileDesc target_fd_; 41 ino_t target_ino_; 42 }; 43 44 // ProcMountNSGuard switches to the target mount namespace and restores the 45 // original upon going out of scope. 46 class ProcMountNSGuard { 47 public: 48 explicit ProcMountNSGuard(ProcMountNS *mount_ns); 49 explicit ProcMountNSGuard(int pid); 50 51 ~ProcMountNSGuard(); 52 53 private: 54 void init(); 55 56 std::unique_ptr<ProcMountNS> mount_ns_instance_; 57 ProcMountNS *mount_ns_; 58 bool entered_; 59 }; 60
