3 files changed, 112 insertions, 4 deletions

diff --git a/otautil/Android.mk b/otautil/Android.mk
index e602f19ee..f7ca9a9ee 100644
--- a/otautil/Android.mk
+++ b/otautil/Android.mk
@@ -18,12 +18,16 @@ include $(CLEAR_VARS)
 LOCAL_SRC_FILES := \
     SysUtil.cpp \
     DirUtil.cpp \
-    ZipUtil.cpp
+    ZipUtil.cpp \
+    ThermalUtil.cpp
 
-LOCAL_STATIC_LIBRARIES := libselinux libbase
+LOCAL_STATIC_LIBRARIES := \
+    libselinux \
+    libbase
 
 LOCAL_MODULE := libotautil
-
-LOCAL_CFLAGS += -Werror -Wall
+LOCAL_CFLAGS := \
+    -Werror \
+    -Wall
 
 include $(BUILD_STATIC_LIBRARY)
diff --git a/otautil/ThermalUtil.cpp b/otautil/ThermalUtil.cpp
new file mode 100644
index 000000000..13d36432a
--- /dev/null
+++ b/otautil/ThermalUtil.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2017 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 "ThermalUtil.h"
+
+#include <dirent.h>
+#include <stdio.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/strings.h>
+
+static constexpr auto THERMAL_PREFIX = "/sys/class/thermal/";
+
+static int thermal_filter(const dirent* de) {
+  if (android::base::StartsWith(de->d_name, "thermal_zone")) {
+    return 1;
+  }
+  return 0;
+}
+
+static std::vector<std::string> InitThermalPaths() {
+  dirent** namelist;
+  int n = scandir(THERMAL_PREFIX, &namelist, thermal_filter, alphasort);
+  if (n == -1) {
+    PLOG(ERROR) << "Failed to scandir " << THERMAL_PREFIX;
+    return {};
+  }
+  if (n == 0) {
+    LOG(ERROR) << "Failed to find CPU thermal info in " << THERMAL_PREFIX;
+    return {};
+  }
+
+  std::vector<std::string> thermal_paths;
+  while (n--) {
+    thermal_paths.push_back(THERMAL_PREFIX + std::string(namelist[n]->d_name) + "/temp");
+    free(namelist[n]);
+  }
+  free(namelist);
+  return thermal_paths;
+}
+
+int GetMaxValueFromThermalZone() {
+  static std::vector<std::string> thermal_paths = InitThermalPaths();
+  int max_temperature = -1;
+  for (const auto& path : thermal_paths) {
+    std::string content;
+    if (!android::base::ReadFileToString(path, &content)) {
+      PLOG(WARNING) << "Failed to read " << path;
+      continue;
+    }
+
+    int temperature;
+    if (!android::base::ParseInt(android::base::Trim(content), &temperature)) {
+      LOG(WARNING) << "Failed to parse integer in " << content;
+      continue;
+    }
+    max_temperature = std::max(temperature, max_temperature);
+  }
+  LOG(INFO) << "current maximum temperature: " << max_temperature;
+  return max_temperature;
+}
\ No newline at end of file
diff --git a/otautil/ThermalUtil.h b/otautil/ThermalUtil.h
new file mode 100644
index 000000000..43ab55940
--- /dev/null
+++ b/otautil/ThermalUtil.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#ifndef OTAUTIL_THERMALUTIL_H
+#define OTAUTIL_THERMALUTIL_H
+
+// We can find the temperature reported by all sensors in /sys/class/thermal/thermal_zone*/temp.
+// Their values are in millidegree Celsius; and we will log the maximum one.
+int GetMaxValueFromThermalZone();
+
+#endif  // OTAUTIL_THERMALUTIL_H