chromium/third_party/perfetto/src/base/logging.cc

/*
 * Copyright (C) 2019 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 "perfetto/base/logging.h"

#include <stdarg.h>
#include <stdio.h>

#if !PERFETTO_BUILDFLAG(PERFETTO_OS_WIN)
#include <unistd.h>  // For isatty()
#endif

#include <atomic>
#include <memory>

#include "perfetto/base/build_config.h"
#include "perfetto/base/time.h"
#include "perfetto/ext/base/crash_keys.h"
#include "perfetto/ext/base/string_utils.h"
#include "perfetto/ext/base/string_view.h"
#include "src/base/log_ring_buffer.h"

#if PERFETTO_ENABLE_LOG_RING_BUFFER() && PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
#include <android/set_abort_message.h>
#endif

namespace perfetto {
namespace base {

namespace {
const char kReset[] = …;
const char kDefault[] = …;
const char kDim[] = …;
const char kRed[] = …;
const char kBoldGreen[] = …;
const char kLightGray[] = …;

std::atomic<LogMessageCallback> g_log_callback{ … };

#if PERFETTO_BUILDFLAG(PERFETTO_STDERR_CRASH_DUMP)
// __attribute__((constructor)) causes a static initializer that automagically
// early runs this function before the main().
void PERFETTO_EXPORT_COMPONENT __attribute__((constructor))
InitDebugCrashReporter() {
  // This function is defined in debug_crash_stack_trace.cc.
  // The dynamic initializer is in logging.cc because logging.cc is included
  // in virtually any target that depends on base. Having it in
  // debug_crash_stack_trace.cc would require figuring out -Wl,whole-archive
  // which is not worth it.
  EnableStacktraceOnCrashForDebug();
}
#endif

#if PERFETTO_ENABLE_LOG_RING_BUFFER()
LogRingBuffer g_log_ring_buffer{};

// This is global to avoid allocating memory or growing too much the stack
// in MaybeSerializeLastLogsForCrashReporting(), which is called from
// arbitrary code paths hitting PERFETTO_CHECK()/FATAL().
char g_crash_buf[kLogRingBufEntries * kLogRingBufMsgLen];
#endif

}  // namespace

void SetLogMessageCallback(LogMessageCallback callback) { … }

void LogMessage(LogLev level,
                const char* fname,
                int line,
                const char* fmt,
                ...) { … }

#if PERFETTO_ENABLE_LOG_RING_BUFFER()
void MaybeSerializeLastLogsForCrashReporting() {
  // Keep this function minimal. This is called from the watchdog thread, often
  // when the system is thrashing.

  // This is racy because two threads could hit a CHECK/FATAL at the same time.
  // But if that happens we have bigger problems, not worth designing around it.
  // The behaviour is still defined in the race case (the string attached to
  // the crash report will contain a mixture of log strings).
  size_t wr = 0;
  wr += SerializeCrashKeys(&g_crash_buf[wr], sizeof(g_crash_buf) - wr);
  wr += g_log_ring_buffer.Read(&g_crash_buf[wr], sizeof(g_crash_buf) - wr);

  // Read() null-terminates the string properly. This is just to avoid UB when
  // two threads race on each other (T1 writes a shorter string, T2
  // overwrites the \0 writing a longer string. T1 continues here before T2
  // finishes writing the longer string with the \0 -> boom.
  g_crash_buf[sizeof(g_crash_buf) - 1] = '\0';

#if PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
  // android_set_abort_message() will cause debuggerd to report the message
  // in the tombstone and in the crash log in logcat.
  // NOTE: android_set_abort_message() can be called only once. This should
  // be called only when we are sure we are about to crash.
  android_set_abort_message(g_crash_buf);
#else
  // Print out the message on stderr on Linux/Mac/Win.
  fputs("\n-----BEGIN PERFETTO PRE-CRASH LOG-----\n", stderr);
  fputs(g_crash_buf, stderr);
  fputs("\n-----END PERFETTO PRE-CRASH LOG-----\n", stderr);
#endif
}
#endif  // PERFETTO_ENABLE_LOG_RING_BUFFER

}  // namespace base
}  // namespace perfetto