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Side by Side Diff: components/metrics/chromeos/metrics_utils.cc

Issue 227873002: Create a histogram serialization mechanism in components/metrics (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Renaming gyp target (nit) Created 6 years, 7 months ago
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1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "components/metrics/chromeos/metrics_utils.h"
6
7 #include <sys/file.h>
8
9 #include <string>
10 #include <vector>
11
12 #include "base/file_util.h"
13 #include "base/files/file_path.h"
14 #include "base/files/scoped_file.h"
15 #include "base/logging.h"
16 #include "base/memory/scoped_ptr.h"
17 #include "base/memory/scoped_vector.h"
18 #include "base/strings/string_split.h"
19 #include "base/strings/string_util.h"
20 #include "components/metrics/chromeos/metric_sample.h"
21
22 #define READ_WRITE_ALL_FILE_FLAGS \
23 (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
24
25 namespace metrics {
26
27 scoped_ptr<MetricSample> MetricsUtils::ReadSample(const std::string& sample) {
28 std::vector<std::string> parts;
29 base::SplitString(sample, '\0', &parts);
30 // We should have two null terminated strings so split should produce
31 // three chunks.
32 if (parts.size() != 3) {
33 DLOG(ERROR) << "splitting message on \\0 produced " << parts.size()
34 << " parts (expected 3)";
35 return scoped_ptr<MetricSample>();
36 }
37 const std::string& name = parts[0];
38 const std::string& value = parts[1];
39
40 if (LowerCaseEqualsASCII(name, "crash")) {
41 return MetricSample::CrashSample(value);
42 } else if (LowerCaseEqualsASCII(name, "histogram")) {
43 return MetricSample::ReadHistogram(value);
44 } else if (LowerCaseEqualsASCII(name, "linearhistogram")) {
45 return MetricSample::ReadLinearHistogram(value);
46 } else if (LowerCaseEqualsASCII(name, "sparsehistogram")) {
47 return MetricSample::ReadSparseHistogram(value);
48 } else if (LowerCaseEqualsASCII(name, "useraction")) {
49 return MetricSample::UserActionSample(value);
50 } else {
51 DLOG(ERROR) << "invalid event type: " << name << ", value: " << value;
52 }
53 return scoped_ptr<MetricSample>();
54 }
55
56 bool MetricsUtils::WriteMetricToFile(const MetricSample* sample,
57 const std::string& filename) {
58 if (!sample->IsValid())
59 return false;
60
61 base::ScopedFD file_descriptor(open(filename.c_str(),
62 O_WRONLY | O_APPEND | O_CREAT,
63 READ_WRITE_ALL_FILE_FLAGS));
64
65 if (file_descriptor.get() < 0) {
66 DLOG(ERROR) << "error openning the file";
67 return false;
68 }
69
70 fchmod(file_descriptor.get(), READ_WRITE_ALL_FILE_FLAGS);
71 // Grab a lock to avoid chrome truncating the file
72 // underneath us. Keep the file locked as briefly as possible.
73 // Freeing file_descriptor will close the file and and remove the lock.
74 if (HANDLE_EINTR(flock(file_descriptor.get(), LOCK_EX)) < 0) {
75 DLOG(ERROR) << "error locking" << filename << " : " << errno;
76 return false;
77 }
78
79 std::string msg = sample->ToString();
80 int32_t size = msg.length() + sizeof(int32_t);
Alexei Svitkine (slow) 2014/05/13 19:52:42 Move |size| to right before it's used, i.e. line 8
bsimonnet 2014/05/13 21:28:00 Actually I should use size below.
81 if (msg.length() > size_t(kMessageMaxLength)) {
82 DLOG(ERROR) << "cannot write message: too long";
83 return false;
84 }
85
86 msg = std::string(reinterpret_cast<char*>(&size), sizeof(int32_t)) + msg;
Alexei Svitkine (slow) 2014/05/13 19:52:42 Can you use two WriteFileDescriptor() calls instea
bsimonnet 2014/05/13 21:28:00 Done
Alexei Svitkine (slow) 2014/05/13 21:30:42 I see. Are there actual big-endian ChromeOS device
Luigi Semenzato 2014/05/13 21:36:35 The producer and the consumer of this data are run
bsimonnet 2014/05/13 21:49:56 Benchan mentioned that there are no big endian mac
87
88 if (base::WriteFileDescriptor(file_descriptor.get(), msg.c_str(), size) !=
89 size) {
90 DLOG(ERROR) << "error writing to " << filename << " : " << errno;
91 return false;
92 }
93
94 return true;
95 }
96
97 void MetricsUtils::ReadAndTruncateMetricsFromFile(
98 const std::string& filename,
99 ScopedVector<MetricSample>* metrics) {
100 struct stat stat_buf;
101 int result;
102
103 result = stat(filename.c_str(), &stat_buf);
104 if (result < 0) {
105 if (errno != ENOENT) {
106 DPLOG(ERROR) << filename << ": bad metrics file stat";
107 }
108 // Nothing to collect---try later.
109 return;
110 }
111 if (stat_buf.st_size == 0) {
112 // Also nothing to collect.
113 return;
114 }
115 base::ScopedFD fd(open(filename.c_str(), O_RDWR));
116 if (fd.get() < 0) {
117 DPLOG(ERROR) << filename << ": cannot open";
118 return;
119 }
120 result = flock(fd.get(), LOCK_EX);
121 if (result < 0) {
122 DPLOG(ERROR) << filename << ": cannot lock";
123 return;
124 }
125 // This processes all messages in the log. Each message starts with a 4-byte
126 // field containing the length of the entire message. The length is followed
127 // by a name-value pair of null-terminated strings. When all messages are
128 // read and processed, or an error occurs, truncate the file to zero size.
129 for (;;) {
130 int32 message_size;
131 result = HANDLE_EINTR(read(fd.get(), &message_size, sizeof(message_size)));
132 if (result < 0) {
133 DPLOG(ERROR) << "reading metrics message header";
134 break;
135 }
136 if (result == 0) { // This indicates a normal EOF.
137 break;
138 }
139 if (result < static_cast<int>(sizeof(message_size))) {
140 DLOG(ERROR) << "bad read size " << result << ", expecting "
141 << sizeof(message_size);
142 break;
143 }
144 // kMessageMaxLength applies to the entire message: the 4-byte
145 // length field and the two null-terminated strings.
146 if (message_size < 2 + static_cast<int>(sizeof(message_size))) {
147 DLOG(ERROR) << "bad message size " << message_size;
148 break;
149 }
150
151 if (message_size > kMessageMaxLength) {
152 DLOG(ERROR) << "message too long : " << message_size;
153 if (HANDLE_EINTR(lseek(fd.get(), message_size - 4, SEEK_CUR)) == -1) {
154 DLOG(ERROR) << "error while skipping message. abort";
155 break;
156 }
157 continue;
158 }
159
160 message_size -= sizeof(message_size); // The message size includes itself.
161 char buffer[kMessageMaxLength];
162 result = HANDLE_EINTR(read(fd.get(), buffer, message_size));
163 if (result < 0) {
164 DPLOG(ERROR) << "reading metrics message body";
165 break;
166 }
167 if (result < message_size) {
168 DLOG(ERROR) << "message too short: length " << result << ", expected "
169 << message_size;
170 break;
171 }
172
173 metrics->push_back(ReadSample(std::string(buffer, message_size)).release());
174 }
175
176 result = ftruncate(fd.get(), 0);
177 if (result < 0) {
178 DPLOG(ERROR) << "truncate metrics log";
179 }
180 result = flock(fd.get(), LOCK_UN);
181 if (result < 0) {
182 DPLOG(ERROR) << "unlock metrics log";
183 }
184 }
185
186 } // namespace metrics
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