Merge "liblog: don't cache property size values and move to own file"

liblog/Android.bp

@@ -17,6 +17,7 @@
 liblog_sources = [
     "log_event_list.cpp",
     "log_event_write.cpp",
+    "log_size.cpp",
     "logger_name.cpp",
     "logger_read.cpp",
     "logger_write.cpp",

liblog/log_size.cpp

@@ -0,0 +1,83 @@
+/*
+ * Copyright 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 <private/android_logger.h>
+
+#include <array>
+#include <optional>
+#include <string>
+
+#include <android-base/parseint.h>
+
+#ifdef __ANDROID__
+#include <sys/system_properties.h>
+#endif
+
+bool __android_logger_valid_buffer_size(unsigned long value) {
+  return LOG_BUFFER_MIN_SIZE <= value && value <= LOG_BUFFER_MAX_SIZE;
+}
+
+#ifdef __ANDROID__
+
+static std::optional<unsigned long> GetBufferSizeProperty(const std::string& key) {
+  char value[PROP_VALUE_MAX] = {};
+  if (__system_property_get(key.c_str(), value) <= 0) {
+    return {};
+  }
+
+  uint32_t size;
+  if (!android::base::ParseByteCount(value, &size)) {
+    return {};
+  }
+
+  if (!__android_logger_valid_buffer_size(size)) {
+    return {};
+  }
+
+  return size;
+}
+
+unsigned long __android_logger_get_buffer_size(log_id_t log_id) {
+  std::string buffer_name = android_log_id_to_name(log_id);
+  std::array<std::string, 4> properties = {
+      "persist.logd.size." + buffer_name,
+      "ro.logd.size." + buffer_name,
+      "persist.logd.size",
+      "ro.logd.size",
+  };
+
+  for (const auto& property : properties) {
+    if (auto size = GetBufferSizeProperty(property)) {
+      return *size;
+    }
+  }
+
+  char value[PROP_VALUE_MAX] = {};
+  if (__system_property_get("ro.config.low_ram", value) > 0 && !strcmp(value, "true")) {
+    return LOG_BUFFER_MIN_SIZE;
+  }
+
+  return LOG_BUFFER_SIZE;
+}
+
+#else
+
+// Default to 1MB for host.
+unsigned long __android_logger_get_buffer_size(log_id_t) {
+  return 1024 * 1024;
+}
+
+#endif

liblog/properties.cpp

@@ -364,153 +364,6 @@ int __android_log_security() {
   return do_cache2_char(&security);
 }
 
-/*
- * Interface that represents the logd buffer size determination so that others
- * need not guess our intentions.
- */
-
-/* cache structure */
-struct cache_property {
-  struct cache cache;
-  char property[PROP_VALUE_MAX];
-};
-
-static void refresh_cache_property(struct cache_property* cache, const char* key) {
-  if (!cache->cache.pinfo) {
-    cache->cache.pinfo = __system_property_find(key);
-    if (!cache->cache.pinfo) {
-      return;
-    }
-  }
-  cache->cache.serial = __system_property_serial(cache->cache.pinfo);
-  __system_property_read(cache->cache.pinfo, 0, cache->property);
-}
-
-bool __android_logger_valid_buffer_size(unsigned long value) {
-  return LOG_BUFFER_MIN_SIZE <= value && value <= LOG_BUFFER_MAX_SIZE;
-}
-
-struct cache2_property_size {
-  pthread_mutex_t lock;
-  uint32_t serial;
-  const char* key_persist;
-  struct cache_property cache_persist;
-  const char* key_ro;
-  struct cache_property cache_ro;
-  unsigned long (*const evaluate)(const struct cache2_property_size* self);
-};
-
-static inline unsigned long do_cache2_property_size(struct cache2_property_size* self) {
-  uint32_t current_serial;
-  int change_detected;
-  unsigned long v;
-
-  if (pthread_mutex_trylock(&self->lock)) {
-    /* We are willing to accept some race in this context */
-    return self->evaluate(self);
-  }
-
-  change_detected = check_cache(&self->cache_persist.cache) || check_cache(&self->cache_ro.cache);
-  current_serial = __system_property_area_serial();
-  if (current_serial != self->serial) {
-    change_detected = 1;
-  }
-  if (change_detected) {
-    refresh_cache_property(&self->cache_persist, self->key_persist);
-    refresh_cache_property(&self->cache_ro, self->key_ro);
-    self->serial = current_serial;
-  }
-  v = self->evaluate(self);
-
-  pthread_mutex_unlock(&self->lock);
-
-  return v;
-}
-
-static unsigned long property_get_size_from_cache(const struct cache_property* cache) {
-  char* cp;
-  unsigned long value = strtoul(cache->property, &cp, 10);
-
-  switch (*cp) {
-    case 'm':
-    case 'M':
-      value *= 1024;
-      [[fallthrough]];
-    case 'k':
-    case 'K':
-      value *= 1024;
-      [[fallthrough]];
-    case '\0':
-      break;
-
-    default:
-      value = 0;
-  }
-
-  if (!__android_logger_valid_buffer_size(value)) {
-    value = 0;
-  }
-
-  return value;
-}
-
-static unsigned long evaluate_property_get_size(const struct cache2_property_size* self) {
-  unsigned long size = property_get_size_from_cache(&self->cache_persist);
-  if (size) {
-    return size;
-  }
-  return property_get_size_from_cache(&self->cache_ro);
-}
-
-unsigned long __android_logger_get_buffer_size(log_id_t logId) {
-  static const char global_tunable[] = "persist.logd.size"; /* Settings App */
-  static const char global_default[] = "ro.logd.size";      /* BoardConfig.mk */
-  static struct cache2_property_size global = {
-      /* clang-format off */
-    PTHREAD_MUTEX_INITIALIZER, 0,
-    global_tunable, { { NULL, 0xFFFFFFFF }, {} },
-    global_default, { { NULL, 0xFFFFFFFF }, {} },
-    evaluate_property_get_size
-      /* clang-format on */
-  };
-  char key_persist[strlen(global_tunable) + strlen(".security") + 1];
-  char key_ro[strlen(global_default) + strlen(".security") + 1];
-  struct cache2_property_size local = {
-      /* clang-format off */
-    PTHREAD_MUTEX_INITIALIZER, 0,
-    key_persist, { { NULL, 0xFFFFFFFF }, {} },
-    key_ro,      { { NULL, 0xFFFFFFFF }, {} },
-    evaluate_property_get_size
-      /* clang-format on */
-  };
-  unsigned long property_size, default_size;
-
-  default_size = do_cache2_property_size(&global);
-  if (!default_size) {
-    char value[PROP_VALUE_MAX] = {};
-    if (__system_property_get("ro.config.low_ram", value) == 0 || strcmp(value, "true") != 0) {
-      default_size = LOG_BUFFER_SIZE;
-    } else {
-      default_size = LOG_BUFFER_MIN_SIZE;
-    }
-  }
-
-  snprintf(key_persist, sizeof(key_persist), "%s.%s", global_tunable,
-           android_log_id_to_name(logId));
-  snprintf(key_ro, sizeof(key_ro), "%s.%s", global_default, android_log_id_to_name(logId));
-  property_size = do_cache2_property_size(&local);
-
-  if (!property_size) {
-    property_size = default_size;
-  }
-
-  if (!property_size) {
-    property_size = LOG_BUFFER_SIZE;
-  }
-
-  return property_size;
-}
-
 #else
 
 int __android_log_is_loggable(int prio, const char*, int) {

logd/LogBufferTest.cpp

@@ -34,16 +34,6 @@ using android::base::Join;
 using android::base::Split;
 using android::base::StringPrintf;
 
-#ifndef __ANDROID__
-unsigned long __android_logger_get_buffer_size(log_id_t) {
-    return 1024 * 1024;
-}
-
-bool __android_logger_valid_buffer_size(unsigned long) {
-    return true;
-}
-#endif
-
 char* android::uidToName(uid_t) {
     return nullptr;
 }

logd/ReplayMessages.cpp

@@ -40,17 +40,6 @@ using android::base::ParseInt;
 using android::base::ParseUint;
 using android::base::Split;
 
-#ifndef __ANDROID__
-// This is hard coded to 1MB on host.  On device use persist.logd.size to configure.
-unsigned long __android_logger_get_buffer_size(log_id_t) {
-    return 1 * 1024 * 1024;
-}
-
-bool __android_logger_valid_buffer_size(unsigned long) {
-    return true;
-}
-#endif
-
 char* android::uidToName(uid_t) {
     return nullptr;
 }

logd/fuzz/log_buffer_log_fuzzer.cpp

@@ -30,16 +30,6 @@
 #define MIN_TAG_ID 1000
 #define TAG_MOD 10
 
-#ifndef __ANDROID__
-unsigned long __android_logger_get_buffer_size(log_id_t) {
-    return 1024 * 1024;
-}
-
-bool __android_logger_valid_buffer_size(unsigned long) {
-    return true;
-}
-#endif
-
 char* android::uidToName(uid_t) {
     return strdup("fake");
 }