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 #include <cstdlib>
24 #include <string>
25 #include <utility>
26 #include <android-base/file.h>
27 #include <android-base/logging.h>
28 #include <android-base/parseint.h>
29 #include "uptime_parser.h"
30
31 namespace {
32
33 const char BOOTSTAT_DATA_DIR[] = "/data/misc/bootstat/";
34
35 // Given a boot even record file at |path|, extracts the event's relative time
36 // from the record into |uptime|.
ParseRecordEventTime(const std::string & path,int32_t * uptime)37 bool ParseRecordEventTime(const std::string& path, int32_t* uptime) {
38 DCHECK_NE(static_cast<int32_t*>(nullptr), uptime);
39
40 struct stat file_stat;
41 if (stat(path.c_str(), &file_stat) == -1) {
42 PLOG(ERROR) << "Failed to read " << path;
43 return false;
44 }
45
46 *uptime = file_stat.st_mtime;
47
48 return true;
49 }
50
51 } // namespace
52
BootEventRecordStore()53 BootEventRecordStore::BootEventRecordStore() {
54 SetStorePath(BOOTSTAT_DATA_DIR);
55 }
56
AddBootEvent(const std::string & event)57 void BootEventRecordStore::AddBootEvent(const std::string& event) {
58 AddBootEventWithValue(event, bootstat::ParseUptime());
59 }
60
61 // The implementation of AddBootEventValue makes use of the mtime file
62 // attribute to store the value associated with a boot event in order to
63 // optimize on-disk size requirements and small-file thrashing.
AddBootEventWithValue(const std::string & event,int32_t value)64 void BootEventRecordStore::AddBootEventWithValue(
65 const std::string& event, int32_t value) {
66 std::string record_path = GetBootEventPath(event);
67 int record_fd = creat(record_path.c_str(), S_IRUSR | S_IWUSR);
68 if (record_fd == -1) {
69 PLOG(ERROR) << "Failed to create " << record_path;
70 return;
71 }
72
73 // Fill out the stat structure for |record_path| in order to get the atime to
74 // set in the utime() call.
75 struct stat file_stat;
76 if (stat(record_path.c_str(), &file_stat) == -1) {
77 PLOG(ERROR) << "Failed to read " << record_path;
78 close(record_fd);
79 return;
80 }
81
82 // Set the |modtime| of the file to store the value of the boot event while
83 // preserving the |actime| (as read by stat).
84 struct utimbuf times = {/* actime */ file_stat.st_atime, /* modtime */ value};
85 if (utime(record_path.c_str(), ×) == -1) {
86 PLOG(ERROR) << "Failed to set mtime for " << record_path;
87 close(record_fd);
88 return;
89 }
90
91 close(record_fd);
92 }
93
GetBootEvent(const std::string & event,BootEventRecord * record) const94 bool BootEventRecordStore::GetBootEvent(
95 const std::string& event, BootEventRecord* record) const {
96 CHECK_NE(static_cast<BootEventRecord*>(nullptr), record);
97 CHECK(!event.empty());
98
99 const std::string record_path = GetBootEventPath(event);
100 int32_t uptime;
101 if (!ParseRecordEventTime(record_path, &uptime)) {
102 LOG(ERROR) << "Failed to parse boot time record: " << record_path;
103 return false;
104 }
105
106 *record = std::make_pair(event, uptime);
107 return true;
108 }
109
110 std::vector<BootEventRecordStore::BootEventRecord> BootEventRecordStore::
GetAllBootEvents() const111 GetAllBootEvents() const {
112 std::vector<BootEventRecord> events;
113
114 std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(store_path_.c_str()), closedir);
115
116 // This case could happen due to external manipulation of the filesystem,
117 // so crash out if the record store doesn't exist.
118 CHECK_NE(static_cast<DIR*>(nullptr), dir.get());
119
120 struct dirent* entry;
121 while ((entry = readdir(dir.get())) != NULL) {
122 // Only parse regular files.
123 if (entry->d_type != DT_REG) {
124 continue;
125 }
126
127 const std::string event = entry->d_name;
128 BootEventRecord record;
129 if (!GetBootEvent(event, &record)) {
130 LOG(ERROR) << "Failed to parse boot time event: " << event;
131 continue;
132 }
133
134 events.push_back(record);
135 }
136
137 return events;
138 }
139
SetStorePath(const std::string & path)140 void BootEventRecordStore::SetStorePath(const std::string& path) {
141 DCHECK_EQ('/', path.back());
142 store_path_ = path;
143 }
144
GetBootEventPath(const std::string & event) const145 std::string BootEventRecordStore::GetBootEventPath(
146 const std::string& event) const {
147 DCHECK_EQ('/', store_path_.back());
148 return store_path_ + event;
149 }
150