1 /* 2 * Copyright (C) 2017 The Android Open Source Project 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 _LOGD_LOG_TAGS_H__ 18 #define _LOGD_LOG_TAGS_H__ 19 20 #include <string> 21 #include <unordered_map> 22 #include <unordered_set> 23 24 #include <utils/RWLock.h> 25 26 class LogTags { 27 // This lock protects all the unordered_map accesses below. It 28 // is a reader/writer lock so that contentions are kept to a 29 // minimum since writes are rare, even administratably when 30 // reads are extended. Resist the temptation to use the writer 31 // lock to protect anything outside the following unordered_maps 32 // as that would increase the reader contentions. Use a separate 33 // mutex to protect the other entities. 34 android::RWLock rwlock; 35 36 // key is Name + "+" + Format 37 std::unordered_map<std::string, uint32_t> key2tag; 38 typedef std::unordered_map<std::string, uint32_t>::const_iterator 39 key2tag_const_iterator; 40 41 // Allows us to manage access permissions based on uid registrants 42 // Global entries are specifically erased. 43 typedef std::unordered_set<uid_t> uid_list; 44 std::unordered_map<uint32_t, uid_list> tag2uid; 45 typedef std::unordered_map<uint32_t, uid_list>::const_iterator 46 tag2uid_const_iterator; 47 48 std::unordered_map<uint32_t, std::string> tag2name; 49 typedef std::unordered_map<uint32_t, std::string>::const_iterator 50 tag2name_const_iterator; 51 52 std::unordered_map<uint32_t, std::string> tag2format; 53 typedef std::unordered_map<uint32_t, std::string>::const_iterator 54 tag2format_const_iterator; 55 56 static const size_t max_per_uid = 256; // Put a cap on the tags per uid 57 std::unordered_map<uid_t, size_t> uid2count; 58 typedef std::unordered_map<uid_t, size_t>::const_iterator 59 uid2count_const_iterator; 60 61 // Dynamic entries are assigned 62 std::unordered_map<uint32_t, size_t> tag2total; 63 typedef std::unordered_map<uint32_t, size_t>::const_iterator 64 tag2total_const_iterator; 65 66 // emplace unique tag 67 uint32_t nameToTag(uid_t uid, const char* name, const char* format); 68 // find unique or associated tag 69 uint32_t nameToTag_locked(const std::string& name, const char* format, 70 bool& unique); 71 72 // Record expected file watermarks to detect corruption. 73 std::unordered_map<std::string, size_t> file2watermark; 74 typedef std::unordered_map<std::string, size_t>::const_iterator 75 file2watermark_const_iterator; 76 77 void ReadPersistEventLogTags(); 78 79 // format helpers 80 // format a single entry, does not need object data 81 static std::string formatEntry(uint32_t tag, uid_t uid, const char* name, 82 const char* format); 83 // caller locks, database lookup, authenticate against uid 84 std::string formatEntry_locked(uint32_t tag, uid_t uid, 85 bool authenticate = true); 86 87 bool RebuildFileEventLogTags(const char* filename, bool warn = true); 88 89 void AddEventLogTags(uint32_t tag, uid_t uid, const std::string& Name, 90 const std::string& Format, const char* source = NULL, 91 bool warn = false); 92 93 void WriteDynamicEventLogTags(uint32_t tag, uid_t uid); 94 void WriteDebugEventLogTags(uint32_t tag, uid_t uid); 95 // push tag details to persistent storage 96 void WritePersistEventLogTags(uint32_t tag, uid_t uid = AID_ROOT, 97 const char* source = NULL); 98 99 static const uint32_t emptyTag = uint32_t(-1); 100 101 public: 102 static const char system_event_log_tags[]; 103 static const char dynamic_event_log_tags[]; 104 // Only for userdebug and eng 105 static const char debug_event_log_tags[]; 106 107 LogTags(); 108 109 void WritePmsgEventLogTags(uint32_t tag, uid_t uid = AID_ROOT); 110 void ReadFileEventLogTags(const char* filename, bool warn = true); 111 112 // reverse lookup from tag 113 const char* tagToName(uint32_t tag) const; 114 const char* tagToFormat(uint32_t tag) const; 115 std::string formatEntry(uint32_t tag, uid_t uid); 116 // find associated tag 117 uint32_t nameToTag(const char* name) const; 118 119 // emplace tag if necessary, provide event-log-tag formated output in string 120 std::string formatGetEventTag(uid_t uid, const char* name, 121 const char* format); 122 }; 123 124 #endif // _LOGD_LOG_TAGS_H__ 125
