1 /*
2 * Copyright (C) 2016 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 #include "boot_event_record_store.h"
18
19 #include <dirent.h>
20 #include <fcntl.h>
21 #include <sys/stat.h>
22 #include <utime.h>
23
24 #include <chrono>
25 #include <cstdlib>
26 #include <string>
27 #include <utility>
28
29 #include <android-base/chrono_utils.h>
30 #include <android-base/file.h>
31 #include <android-base/logging.h>
32 #include <android-base/parseint.h>
33
34 namespace {
35
36 const char BOOTSTAT_DATA_DIR[] = "/data/misc/bootstat/";
37
38 // Given a boot even record file at |path|, extracts the event's relative time
39 // from the record into |uptime|.
ParseRecordEventTime(const std::string & path,int32_t * uptime)40 bool ParseRecordEventTime(const std::string& path, int32_t* uptime) {
41 DCHECK_NE(static_cast<int32_t*>(nullptr), uptime);
42
43 struct stat file_stat;
44 if (stat(path.c_str(), &file_stat) == -1) {
45 PLOG(ERROR) << "Failed to read " << path;
46 return false;
47 }
48
49 *uptime = file_stat.st_mtime;
50
51 return true;
52 }
53
54 } // namespace
55
BootEventRecordStore()56 BootEventRecordStore::BootEventRecordStore() {
57 SetStorePath(BOOTSTAT_DATA_DIR);
58 }
59
AddBootEvent(const std::string & event)60 void BootEventRecordStore::AddBootEvent(const std::string& event) {
61 auto uptime = std::chrono::duration_cast<std::chrono::seconds>(
62 android::base::boot_clock::now().time_since_epoch());
63 AddBootEventWithValue(event, uptime.count());
64 }
65
66 // The implementation of AddBootEventValue makes use of the mtime file
67 // attribute to store the value associated with a boot event in order to
68 // optimize on-disk size requirements and small-file thrashing.
AddBootEventWithValue(const std::string & event,int32_t value)69 void BootEventRecordStore::AddBootEventWithValue(const std::string& event, int32_t value) {
70 std::string record_path = GetBootEventPath(event);
71 int record_fd = creat(record_path.c_str(), S_IRUSR | S_IWUSR);
72 if (record_fd == -1) {
73 PLOG(ERROR) << "Failed to create " << record_path;
74 return;
75 }
76
77 // Fill out the stat structure for |record_path| in order to get the atime to
78 // set in the utime() call.
79 struct stat file_stat;
80 if (stat(record_path.c_str(), &file_stat) == -1) {
81 PLOG(ERROR) << "Failed to read " << record_path;
82 close(record_fd);
83 return;
84 }
85
86 // Set the |modtime| of the file to store the value of the boot event while
87 // preserving the |actime| (as read by stat).
88 struct utimbuf times = {/* actime */ file_stat.st_atime, /* modtime */ value};
89 if (utime(record_path.c_str(), ×) == -1) {
90 PLOG(ERROR) << "Failed to set mtime for " << record_path;
91 close(record_fd);
92 return;
93 }
94
95 close(record_fd);
96 }
97
GetBootEvent(const std::string & event,BootEventRecord * record) const98 bool BootEventRecordStore::GetBootEvent(const std::string& event, BootEventRecord* record) const {
99 CHECK_NE(static_cast<BootEventRecord*>(nullptr), record);
100 CHECK(!event.empty());
101
102 const std::string record_path = GetBootEventPath(event);
103 int32_t uptime;
104 if (!ParseRecordEventTime(record_path, &uptime)) {
105 LOG(ERROR) << "Failed to parse boot time record: " << record_path;
106 return false;
107 }
108
109 *record = std::make_pair(event, uptime);
110 return true;
111 }
112
GetAllBootEvents() const113 std::vector<BootEventRecordStore::BootEventRecord> BootEventRecordStore::GetAllBootEvents() const {
114 std::vector<BootEventRecord> events;
115
116 std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(store_path_.c_str()), closedir);
117
118 // This case could happen due to external manipulation of the filesystem,
119 // so crash out if the record store doesn't exist.
120 CHECK_NE(static_cast<DIR*>(nullptr), dir.get());
121
122 struct dirent* entry;
123 while ((entry = readdir(dir.get())) != NULL) {
124 // Only parse regular files.
125 if (entry->d_type != DT_REG) {
126 continue;
127 }
128
129 const std::string event = entry->d_name;
130 BootEventRecord record;
131 if (!GetBootEvent(event, &record)) {
132 LOG(ERROR) << "Failed to parse boot time event: " << event;
133 continue;
134 }
135
136 events.push_back(record);
137 }
138
139 return events;
140 }
141
SetStorePath(const std::string & path)142 void BootEventRecordStore::SetStorePath(const std::string& path) {
143 DCHECK_EQ('/', path.back());
144 store_path_ = path;
145 }
146
GetBootEventPath(const std::string & event) const147 std::string BootEventRecordStore::GetBootEventPath(const std::string& event) const {
148 DCHECK_EQ('/', store_path_.back());
149 return store_path_ + event;
150 }
151