logd: add LogBufferTest.cpp

Add a standalone test of log buffers that does not interact with the
logd running on the device.

Test: this new test
Change-Id: Ie4ecc50289ef164aa47cc72ddeeb9b28e776db94
diff --git a/logd/LogBufferTest.cpp b/logd/LogBufferTest.cpp
new file mode 100644
index 0000000..806fd16
--- /dev/null
+++ b/logd/LogBufferTest.cpp
@@ -0,0 +1,327 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+#include "LogBuffer.h"
+
+#include <unistd.h>
+
+#include <memory>
+#include <vector>
+
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <gtest/gtest.h>
+
+#include "ChattyLogBuffer.h"
+#include "LogReaderList.h"
+#include "LogReaderThread.h"
+#include "LogStatistics.h"
+#include "LogTags.h"
+#include "LogWhiteBlackList.h"
+#include "LogWriter.h"
+
+using android::base::Join;
+using android::base::StringPrintf;
+
+void android::prdebug(const char* fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    fprintf(stderr, "\n");
+    va_end(ap);
+}
+
+char* android::uidToName(uid_t) {
+    return nullptr;
+}
+
+class TestWriter : public LogWriter {
+  public:
+    TestWriter(std::vector<std::pair<logger_entry, std::string>>* msgs, bool* released)
+        : LogWriter(0, true, true), msgs_(msgs), released_(released) {}
+    bool Write(const logger_entry& entry, const char* message) override {
+        msgs_->emplace_back(entry, std::string(message, entry.len));
+        return true;
+    }
+
+    void Release() {
+        if (released_) *released_ = true;
+    }
+
+    std::string name() const override { return "test_writer"; }
+
+  private:
+    std::vector<std::pair<logger_entry, std::string>>* msgs_;
+    bool* released_;
+};
+
+class LogBufferTest : public testing::Test {
+  protected:
+    void SetUp() override {
+        log_buffer_.reset(new ChattyLogBuffer(&reader_list_, &tags_, &prune_, &stats_));
+    }
+
+    void FixupMessages(std::vector<std::pair<logger_entry, std::string>>* messages) {
+        for (auto& [entry, message] : *messages) {
+            entry.hdr_size = sizeof(logger_entry);
+            entry.len = message.size();
+        }
+    }
+
+    void LogMessages(const std::vector<std::pair<logger_entry, std::string>>& messages) {
+        for (auto& [entry, message] : messages) {
+            log_buffer_->Log(static_cast<log_id_t>(entry.lid), log_time(entry.sec, entry.nsec),
+                             entry.uid, entry.pid, entry.tid, message.c_str(), message.size());
+        }
+    }
+
+    std::vector<std::string> CompareLoggerEntries(const logger_entry& expected,
+                                                  const logger_entry& result) {
+        std::vector<std::string> errors;
+        if (expected.len != result.len) {
+            errors.emplace_back(
+                    StringPrintf("len: %" PRIu16 " vs %" PRIu16, expected.len, result.len));
+        }
+        if (expected.hdr_size != result.hdr_size) {
+            errors.emplace_back(StringPrintf("hdr_size: %" PRIu16 " vs %" PRIu16, expected.hdr_size,
+                                             result.hdr_size));
+        }
+        if (expected.pid != result.pid) {
+            errors.emplace_back(
+                    StringPrintf("pid: %" PRIi32 " vs %" PRIi32, expected.pid, result.pid));
+        }
+        if (expected.tid != result.tid) {
+            errors.emplace_back(
+                    StringPrintf("tid: %" PRIu32 " vs %" PRIu32, expected.tid, result.tid));
+        }
+        if (expected.sec != result.sec) {
+            errors.emplace_back(
+                    StringPrintf("sec: %" PRIu32 " vs %" PRIu32, expected.sec, result.sec));
+        }
+        if (expected.nsec != result.nsec) {
+            errors.emplace_back(
+                    StringPrintf("nsec: %" PRIu32 " vs %" PRIu32, expected.nsec, result.nsec));
+        }
+        if (expected.lid != result.lid) {
+            errors.emplace_back(
+                    StringPrintf("lid: %" PRIu32 " vs %" PRIu32, expected.lid, result.lid));
+        }
+        if (expected.uid != result.uid) {
+            errors.emplace_back(
+                    StringPrintf("uid: %" PRIu32 " vs %" PRIu32, expected.uid, result.uid));
+        }
+        return errors;
+    }
+
+    std::string CompareMessages(const std::string& expected, const std::string& result) {
+        if (expected == result) {
+            return {};
+        }
+        auto shorten_string = [](const std::string& in) {
+            if (in.size() > 10) {
+                return in.substr(0, 10) + "...";
+            }
+            return in;
+        };
+
+        size_t diff_index = 0;
+        for (; diff_index < std::min(expected.size(), result.size()); ++diff_index) {
+            if (expected[diff_index] != result[diff_index]) {
+                break;
+            }
+        }
+
+        if (diff_index < 10) {
+            auto expected_short = shorten_string(expected);
+            auto result_short = shorten_string(result);
+            return StringPrintf("msg: %s vs %s", expected_short.c_str(), result_short.c_str());
+        }
+
+        auto expected_short = shorten_string(expected.substr(diff_index));
+        auto result_short = shorten_string(result.substr(diff_index));
+        return StringPrintf("msg: index %zu: %s vs %s", diff_index, expected_short.c_str(),
+                            result_short.c_str());
+    }
+
+    void CompareLogMessages(const std::vector<std::pair<logger_entry, std::string>>& expected,
+                            const std::vector<std::pair<logger_entry, std::string>>& result) {
+        EXPECT_EQ(expected.size(), result.size());
+        size_t end = std::min(expected.size(), result.size());
+        size_t num_errors = 0;
+        for (size_t i = 0; i < end; ++i) {
+            auto errors = CompareLoggerEntries(expected[i].first, result[i].first);
+            auto msg_error = CompareMessages(expected[i].second, result[i].second);
+            if (!msg_error.empty()) {
+                errors.emplace_back(msg_error);
+            }
+            if (!errors.empty()) {
+                GTEST_LOG_(ERROR) << "Mismatch log message " << i << " " << Join(errors, " ");
+                ++num_errors;
+            }
+        }
+        EXPECT_EQ(0U, num_errors);
+    }
+
+    LogReaderList reader_list_;
+    LogTags tags_;
+    PruneList prune_;
+    LogStatistics stats_{false};
+    std::unique_ptr<LogBuffer> log_buffer_;
+};
+
+TEST_F(LogBufferTest, smoke) {
+    std::vector<std::pair<logger_entry, std::string>> log_messages = {
+            {{
+                     .pid = 1,
+                     .tid = 1,
+                     .sec = 1234,
+                     .nsec = 323001,
+                     .lid = LOG_ID_MAIN,
+                     .uid = 0,
+             },
+             "smoke test"},
+    };
+    FixupMessages(&log_messages);
+    LogMessages(log_messages);
+
+    std::vector<std::pair<logger_entry, std::string>> read_log_messages;
+    std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, nullptr));
+    uint64_t flush_result = log_buffer_->FlushTo(test_writer.get(), 1, nullptr, nullptr);
+    EXPECT_EQ(1ULL, flush_result);
+    CompareLogMessages(log_messages, read_log_messages);
+}
+
+TEST_F(LogBufferTest, smoke_with_reader_thread) {
+    std::vector<std::pair<logger_entry, std::string>> log_messages = {
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20001, .lid = LOG_ID_MAIN, .uid = 0},
+             "first"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20002, .lid = LOG_ID_MAIN, .uid = 0},
+             "second"},
+            {{.pid = 100, .tid = 2, .sec = 10000, .nsec = 20003, .lid = LOG_ID_KERNEL, .uid = 0},
+             "third"},
+            {{.pid = 10, .tid = 2, .sec = 10000, .nsec = 20004, .lid = LOG_ID_MAIN, .uid = 0},
+             "fourth"},
+            {{.pid = 1, .tid = 2, .sec = 10000, .nsec = 20005, .lid = LOG_ID_RADIO, .uid = 0},
+             "fifth"},
+            {{.pid = 2, .tid = 2, .sec = 10000, .nsec = 20006, .lid = LOG_ID_RADIO, .uid = 0},
+             "sixth"},
+            {{.pid = 3, .tid = 2, .sec = 10000, .nsec = 20007, .lid = LOG_ID_RADIO, .uid = 0},
+             "seventh"},
+            {{.pid = 4, .tid = 2, .sec = 10000, .nsec = 20008, .lid = LOG_ID_MAIN, .uid = 0},
+             "eighth"},
+            {{.pid = 5, .tid = 2, .sec = 10000, .nsec = 20009, .lid = LOG_ID_CRASH, .uid = 0},
+             "nineth"},
+            {{.pid = 6, .tid = 2, .sec = 10000, .nsec = 20011, .lid = LOG_ID_MAIN, .uid = 0},
+             "tenth"},
+    };
+    FixupMessages(&log_messages);
+    LogMessages(log_messages);
+
+    std::vector<std::pair<logger_entry, std::string>> read_log_messages;
+    bool released = false;
+
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
+        std::unique_ptr<LogReaderThread> log_reader(
+                new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
+                                    0, ~0, 0, {}, 1, {}));
+        reader_list_.reader_threads().emplace_back(std::move(log_reader));
+    }
+
+    while (!released) {
+        usleep(5000);
+    }
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        EXPECT_EQ(0U, reader_list_.reader_threads().size());
+    }
+    CompareLogMessages(log_messages, read_log_messages);
+}
+
+// Generate random messages, set the 'sec' parameter explicit though, to be able to track the
+// expected order of messages.
+std::pair<logger_entry, std::string> GenerateRandomLogMessage(uint32_t sec) {
+    auto rand_uint32 = [](int max) -> uint32_t { return rand() % max; };
+    logger_entry entry = {
+            .hdr_size = sizeof(logger_entry),
+            .pid = rand() % 5000,
+            .tid = rand_uint32(5000),
+            .sec = sec,
+            .nsec = rand_uint32(NS_PER_SEC),
+            .lid = rand_uint32(LOG_ID_STATS),
+            .uid = rand_uint32(100000),
+    };
+
+    // See comment in ChattyLogBuffer::Log() for why this is disallowed.
+    if (entry.nsec % 1000 == 0) {
+        ++entry.nsec;
+    }
+
+    if (entry.lid == LOG_ID_EVENTS) {
+        entry.lid = LOG_ID_KERNEL;
+    }
+
+    std::string message;
+    char priority = ANDROID_LOG_INFO + rand() % 2;
+    message.push_back(priority);
+
+    int tag_length = 2 + rand() % 10;
+    for (int i = 0; i < tag_length; ++i) {
+        message.push_back('a' + rand() % 26);
+    }
+    message.push_back('\0');
+
+    int msg_length = 2 + rand() % 1000;
+    for (int i = 0; i < msg_length; ++i) {
+        message.push_back('a' + rand() % 26);
+    }
+    message.push_back('\0');
+
+    entry.len = message.size();
+
+    return {entry, message};
+}
+
+TEST_F(LogBufferTest, random_messages) {
+    srand(1);
+    std::vector<std::pair<logger_entry, std::string>> log_messages;
+    for (size_t i = 0; i < 1000; ++i) {
+        log_messages.emplace_back(GenerateRandomLogMessage(i));
+    }
+    LogMessages(log_messages);
+
+    std::vector<std::pair<logger_entry, std::string>> read_log_messages;
+    bool released = false;
+
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        std::unique_ptr<LogWriter> test_writer(new TestWriter(&read_log_messages, &released));
+        std::unique_ptr<LogReaderThread> log_reader(
+                new LogReaderThread(log_buffer_.get(), &reader_list_, std::move(test_writer), true,
+                                    0, ~0, 0, {}, 1, {}));
+        reader_list_.reader_threads().emplace_back(std::move(log_reader));
+    }
+
+    while (!released) {
+        usleep(5000);
+    }
+    {
+        auto lock = std::unique_lock{reader_list_.reader_threads_lock()};
+        EXPECT_EQ(0U, reader_list_.reader_threads().size());
+    }
+    CompareLogMessages(log_messages, read_log_messages);
+}