1 files changed, 118 insertions, 0 deletions

diff --git a/logd/LogTags.h b/logd/LogTags.h
new file mode 100644
index 000000000..37a6d9632
--- /dev/null
+++ b/logd/LogTags.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _LOGD_LOG_TAGS_H__
+#define _LOGD_LOG_TAGS_H__
+
+#include <unordered_map>
+#include <unordered_set>
+#include <string>
+
+#include <utils/RWLock.h>
+
+class LogTags {
+    // This lock protects all the unordered_map accesses below.  It
+    // is a reader/writer lock so that contentions are kept to a
+    // minimum since writes are rare, even administratably when
+    // reads are extended.  Resist the temptation to use the writer
+    // lock to protect anything outside the following unordered_maps
+    // as that would increase the reader contentions.  Use a separate
+    // mutex to protect the other entities.
+    android::RWLock rwlock;
+
+    // key is Name + "+" + Format
+    std::unordered_map<std::string, uint32_t> key2tag;
+    typedef std::unordered_map<std::string, uint32_t>::const_iterator key2tag_const_iterator;
+
+    // Allows us to manage access permissions based on uid registrants
+    // Global entries are specifically erased.
+    typedef std::unordered_set<uid_t> uid_list;
+    std::unordered_map<uint32_t, uid_list> tag2uid;
+    typedef std::unordered_map<uint32_t, uid_list>::const_iterator tag2uid_const_iterator;
+
+    std::unordered_map<uint32_t, std::string> tag2name;
+    typedef std::unordered_map<uint32_t, std::string>::const_iterator tag2name_const_iterator;
+
+    std::unordered_map<uint32_t, std::string> tag2format;
+    typedef std::unordered_map<uint32_t, std::string>::const_iterator tag2format_const_iterator;
+
+    static const size_t max_per_uid = 256; // Put a cap on the tags per uid
+    std::unordered_map<uid_t, size_t> uid2count;
+    typedef std::unordered_map<uid_t, size_t>::const_iterator uid2count_const_iterator;
+
+    // Dynamic entries are assigned
+    std::unordered_map<uint32_t, size_t> tag2total;
+    typedef std::unordered_map<uint32_t, size_t>::const_iterator tag2total_const_iterator;
+
+    // emplace unique tag
+    uint32_t nameToTag(uid_t uid, const char* name, const char* format);
+    // find unique or associated tag
+    uint32_t nameToTag_locked(const std::string& name, const char* format, bool &unique);
+
+    // Record expected file watermarks to detect corruption.
+    std::unordered_map<std::string, size_t> file2watermark;
+    typedef std::unordered_map<std::string, size_t>::const_iterator file2watermark_const_iterator;
+
+    void ReadPersistEventLogTags();
+
+    // format helpers
+    // format a single entry, does not need object data
+    static std::string formatEntry(uint32_t tag, uid_t uid,
+                                   const char* name, const char* format);
+    // caller locks, database lookup, authenticate against uid
+    std::string formatEntry_locked(uint32_t tag, uid_t uid,
+                                   bool authenticate = true);
+
+    bool RebuildFileEventLogTags(const char* filename, bool warn = true);
+
+    void AddEventLogTags(uint32_t tag, uid_t uid,
+                         const std::string& Name, const std::string& Format,
+                         const char* source = NULL, bool warn = false);
+
+    void WriteDynamicEventLogTags(uint32_t tag, uid_t uid);
+    void WriteDebugEventLogTags(uint32_t tag, uid_t uid);
+    // push tag details to persistent storage
+    void WritePersistEventLogTags(uint32_t tag,
+                                  uid_t uid = AID_ROOT,
+                                  const char* source = NULL);
+
+    static const uint32_t emptyTag = uint32_t(-1);
+
+public:
+
+    static const char system_event_log_tags[];
+    static const char dynamic_event_log_tags[];
+    // Only for userdebug and eng
+    static const char debug_event_log_tags[];
+
+    LogTags();
+
+    void WritePmsgEventLogTags(uint32_t tag, uid_t uid = AID_ROOT);
+    void ReadFileEventLogTags(const char* filename, bool warn = true);
+
+    // reverse lookup from tag
+    const char* tagToName(uint32_t tag) const;
+    const char* tagToFormat(uint32_t tag) const;
+    // find associated tag
+    uint32_t nameToTag(const char* name) const;
+
+    // emplace tag if necessary, provide event-log-tag formated output in string
+    std::string formatGetEventTag(uid_t uid,
+                                  const char* name,
+                                  const char* format);
+};
+
+#endif // _LOGD_LOG_TAGS_H__