1 /* 2 * Copyright 2018 Google, Inc 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef _LIBDM_DMTABLE_H_ 18 #define _LIBDM_DMTABLE_H_ 19 20 #include <stdint.h> 21 22 #include <memory> 23 #include <string> 24 #include <vector> 25 26 #include "dm_target.h" 27 28 namespace android { 29 namespace dm { 30 31 class DmTable { 32 public: DmTable()33 DmTable() : num_sectors_(0), readonly_(false) {} 34 35 // Adds a target to the device mapper table for a range specified in the target object. 36 // The function will return 'true' if the target was successfully added and doesn't overlap with 37 // any of the existing targets in the table. Gaps are allowed. The final check, including 38 // overlaps and gaps are done before loading the table. Returns 'false' on failure. 39 bool AddTarget(std::unique_ptr<DmTarget>&& target); 40 41 // Removes a target from the table for the range specified in the target object. Returns 'false' 42 // if the target name doesn't match with the one in the table. Returns 'true' if target is 43 // successfully removed. 44 bool RemoveTarget(std::unique_ptr<DmTarget>&& target); 45 46 // Adds a target, constructing it in-place for convenience. For example, 47 // 48 // table.Emplace<DmTargetZero>(0, num_sectors); 49 template <typename T, typename... Args> Emplace(Args &&...args)50 bool Emplace(Args&&... args) { 51 return AddTarget(std::make_unique<T>(std::forward<Args>(args)...)); 52 } 53 54 // Checks the table to make sure it is valid. i.e. Checks for range overlaps, range gaps 55 // and returns 'true' if the table is ready to be loaded into kernel. Returns 'false' if the 56 // table is malformed. 57 bool valid() const; 58 59 // Returns the total number of targets. num_targets()60 size_t num_targets() const { return targets_.size(); } 61 62 // Returns the total size represented by the table in terms of number of 512-byte sectors. 63 // NOTE: This function will overlook if there are any gaps in the targets added in the table. 64 uint64_t num_sectors() const; 65 66 // Returns the string represntation of the table that is ready to be passed into the kernel 67 // as part of the DM_TABLE_LOAD ioctl. 68 std::string Serialize() const; 69 set_readonly(bool readonly)70 void set_readonly(bool readonly) { readonly_ = readonly; } readonly()71 bool readonly() const { return readonly_; } 72 73 ~DmTable() = default; 74 75 private: 76 // list of targets defined in this table sorted by 77 // their start and end sectors. 78 // Note: Overlapping targets MUST never be added in this list. 79 std::vector<std::unique_ptr<DmTarget>> targets_; 80 81 // Total size in terms of # of sectors, as calculated by looking at the last and the first 82 // target in 'target_'. 83 uint64_t num_sectors_; 84 85 // True if the device should be read-only; false otherwise. 86 bool readonly_; 87 }; 88 89 } // namespace dm 90 } // namespace android 91 92 #endif /* _LIBDM_DMTABLE_H_ */ 93