1 files changed, 87 insertions, 0 deletions
diff --git a/logging.cc b/logging.cc
new file mode 100644
index 00000000..6320e368
--- /dev/null
+++ b/logging.cc
@@ -0,0 +1,87 @@
+//
+// Copyright (C) 2020 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 <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+
+#include <base/files/file_util.h>
+#include <base/logging.h>
+#include <base/strings/string_util.h>
+#include <base/strings/stringprintf.h>
+
+#include "update_engine/common/utils.h"
+#include "update_engine/logging.h"
+
+using std::string;
+
+namespace chromeos_update_engine {
+
+namespace {
+
+constexpr char kSystemLogsRoot[] = "/var/log";
+
+void SetupLogSymlink(const string& symlink_path, const string& log_path) {
+  // TODO(petkov): To ensure a smooth transition between non-timestamped and
+  // timestamped logs, move an existing log to start the first timestamped
+  // one. This code can go away once all clients are switched to this version or
+  // we stop caring about the old-style logs.
+  if (utils::FileExists(symlink_path.c_str()) &&
+      !utils::IsSymlink(symlink_path.c_str())) {
+    base::ReplaceFile(
+        base::FilePath(symlink_path), base::FilePath(log_path), nullptr);
+  }
+  base::DeleteFile(base::FilePath(symlink_path), true);
+  if (symlink(log_path.c_str(), symlink_path.c_str()) == -1) {
+    PLOG(ERROR) << "Unable to create symlink " << symlink_path
+                << " pointing at " << log_path;
+  }
+}
+
+string SetupLogFile(const string& kLogsRoot) {
+  const string kLogSymlink = kLogsRoot + "/update_engine.log";
+  const string kLogsDir = kLogsRoot + "/update_engine";
+  const string kLogPath =
+      base::StringPrintf("%s/update_engine.%s",
+                         kLogsDir.c_str(),
+                         utils::GetTimeAsString(::time(nullptr)).c_str());
+  mkdir(kLogsDir.c_str(), 0755);
+  SetupLogSymlink(kLogSymlink, kLogPath);
+  return kLogSymlink;
+}
+
+}  // namespace
+
+void SetupLogging(bool log_to_system, bool log_to_file) {
+  logging::LoggingSettings log_settings;
+  log_settings.lock_log = logging::DONT_LOCK_LOG_FILE;
+  log_settings.logging_dest = static_cast<logging::LoggingDestination>(
+      (log_to_system ? logging::LOG_TO_SYSTEM_DEBUG_LOG : 0) |
+      (log_to_file ? logging::LOG_TO_FILE : 0));
+  log_settings.log_file = nullptr;
+
+  string log_file;
+  if (log_to_file) {
+    log_file = SetupLogFile(kSystemLogsRoot);
+    log_settings.delete_old = logging::APPEND_TO_OLD_LOG_FILE;
+    log_settings.log_file = log_file.c_str();
+  }
+  logging::InitLogging(log_settings);
+}
+
+}  // namespace chromeos_update_engine