base/sys_info_android.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/sys_info.h"
   6
   7 #include <dlfcn.h>
   8 #include <sys/system_properties.h>
   9
  10 #include "base/android/sys_utils.h"
  11 #include "base/lazy_instance.h"
  12 #include "base/logging.h"
  13 #include "base/strings/string_number_conversions.h"
  14 #include "base/strings/string_piece.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/sys_info_internal.h"
  17
  18 #if (__ANDROID_API__ >= 21 /* 5.0 - Lollipop */)
  19
  20 namespace {
  21
  22 typedef int (SystemPropertyGetFunction)(const char*, char*);
  23
  24 SystemPropertyGetFunction* DynamicallyLoadRealSystemPropertyGet() {
  25   // libc.so should already be open, get a handle to it.
  26   void* handle = dlopen("libc.so", RTLD_NOLOAD);
  27   if (!handle) {
  28     LOG(FATAL) << "Cannot dlopen libc.so: " << dlerror();
  29   }
  30   SystemPropertyGetFunction* real_system_property_get =
  31       reinterpret_cast<SystemPropertyGetFunction*>(
  32           dlsym(handle, "__system_property_get"));
  33   if (!real_system_property_get) {
  34     LOG(FATAL) << "Cannot resolve __system_property_get(): " << dlerror();
  35   }
  36   return real_system_property_get;
  37 }
  38
  39 static base::LazyInstance<base::internal::LazySysInfoValue<
  40     SystemPropertyGetFunction*, DynamicallyLoadRealSystemPropertyGet> >::Leaky
  41     g_lazy_real_system_property_get = LAZY_INSTANCE_INITIALIZER;
  42
  43 }  // namespace
  44
  45 // Android 'L' removes __system_property_get from the NDK, however it is still
  46 // a hidden symbol in libc. Until we remove all calls of __system_property_get
  47 // from Chrome we work around this by defining a weak stub here, which uses
  48 // dlsym to but ensures that Chrome uses the real system
  49 // implementatation when loaded.  http://crbug.com/392191.
  50 int __system_property_get(const char* name, char* value) {
  51   return g_lazy_real_system_property_get.Get().value()(name, value);
  52 }
  53
  54 #endif
  55
  56 namespace {
  57
  58 // Default version of Android to fall back to when actual version numbers
  59 // cannot be acquired. Use the latest Android release with a higher bug fix
  60 // version to avoid unnecessarily comparison errors with the latest release.
  61 // This should be manually kept up-to-date on each Android release.
  62 const int kDefaultAndroidMajorVersion = 5;
  63 const int kDefaultAndroidMinorVersion = 0;
  64 const int kDefaultAndroidBugfixVersion = 99;
  65
  66 // Parse out the OS version numbers from the system properties.
  67 void ParseOSVersionNumbers(const char* os_version_str,
  68                            int32 *major_version,
  69                            int32 *minor_version,
  70                            int32 *bugfix_version) {
  71   if (os_version_str[0]) {
  72     // Try to parse out the version numbers from the string.
  73     int num_read = sscanf(os_version_str, "%d.%d.%d", major_version,
  74                           minor_version, bugfix_version);
  75
  76     if (num_read > 0) {
  77       // If we don't have a full set of version numbers, make the extras 0.
  78       if (num_read < 2) *minor_version = 0;
  79       if (num_read < 3) *bugfix_version = 0;
  80       return;
  81     }
  82   }
  83
  84   // For some reason, we couldn't parse the version number string.
  85   *major_version = kDefaultAndroidMajorVersion;
  86   *minor_version = kDefaultAndroidMinorVersion;
  87   *bugfix_version = kDefaultAndroidBugfixVersion;
  88 }
  89
  90 // Parses a system property (specified with unit 'k','m' or 'g').
  91 // Returns a value in bytes.
  92 // Returns -1 if the string could not be parsed.
  93 int64 ParseSystemPropertyBytes(const base::StringPiece& str) {
  94   const int64 KB = 1024;
  95   const int64 MB = 1024 * KB;
  96   const int64 GB = 1024 * MB;
  97   if (str.size() == 0u)
  98     return -1;
  99   int64 unit_multiplier = 1;
 100   size_t length = str.size();
 101   if (str[length - 1] == 'k') {
 102     unit_multiplier = KB;
 103     length--;
 104   } else if (str[length - 1] == 'm') {
 105     unit_multiplier = MB;
 106     length--;
 107   } else if (str[length - 1] == 'g') {
 108     unit_multiplier = GB;
 109     length--;
 110   }
 111   int64 result = 0;
 112   bool parsed = base::StringToInt64(str.substr(0, length), &result);
 113   bool negative = result <= 0;
 114   bool overflow = result >= std::numeric_limits<int64>::max() / unit_multiplier;
 115   if (!parsed || negative || overflow)
 116     return -1;
 117   return result * unit_multiplier;
 118 }
 119
 120 int GetDalvikHeapSizeMB() {
 121   char heap_size_str[PROP_VALUE_MAX];
 122   __system_property_get("dalvik.vm.heapsize", heap_size_str);
 123   // dalvik.vm.heapsize property is writable by a root user.
 124   // Clamp it to reasonable range as a sanity check,
 125   // a typical android device will never have less than 48MB.
 126   const int64 MB = 1024 * 1024;
 127   int64 result = ParseSystemPropertyBytes(heap_size_str);
 128   if (result == -1) {
 129      // We should consider not exposing these values if they are not reliable.
 130      LOG(ERROR) << "Can't parse dalvik.vm.heapsize: " << heap_size_str;
 131      result = base::SysInfo::AmountOfPhysicalMemoryMB() / 3;
 132   }
 133   result = std::min<int64>(std::max<int64>(32 * MB, result), 1024 * MB) / MB;
 134   return static_cast<int>(result);
 135 }
 136
 137 int GetDalvikHeapGrowthLimitMB() {
 138   char heap_size_str[PROP_VALUE_MAX];
 139   __system_property_get("dalvik.vm.heapgrowthlimit", heap_size_str);
 140   // dalvik.vm.heapgrowthlimit property is writable by a root user.
 141   // Clamp it to reasonable range as a sanity check,
 142   // a typical android device will never have less than 24MB.
 143   const int64 MB = 1024 * 1024;
 144   int64 result = ParseSystemPropertyBytes(heap_size_str);
 145   if (result == -1) {
 146      // We should consider not exposing these values if they are not reliable.
 147      LOG(ERROR) << "Can't parse dalvik.vm.heapgrowthlimit: " << heap_size_str;
 148      result = base::SysInfo::AmountOfPhysicalMemoryMB() / 6;
 149   }
 150   result = std::min<int64>(std::max<int64>(16 * MB, result), 512 * MB) / MB;
 151   return static_cast<int>(result);
 152 }
 153
 154 }  // anonymous namespace
 155
 156 namespace base {
 157
 158 std::string SysInfo::OperatingSystemName() {
 159   return "Android";
 160 }
 161
 162 std::string SysInfo::GetAndroidBuildCodename() {
 163   char os_version_codename_str[PROP_VALUE_MAX];
 164   __system_property_get("ro.build.version.codename", os_version_codename_str);
 165   return std::string(os_version_codename_str);
 166 }
 167
 168 std::string SysInfo::GetAndroidBuildID() {
 169   char os_build_id_str[PROP_VALUE_MAX];
 170   __system_property_get("ro.build.id", os_build_id_str);
 171   return std::string(os_build_id_str);
 172 }
 173
 174 std::string SysInfo::GetDeviceName() {
 175   char device_model_str[PROP_VALUE_MAX];
 176   __system_property_get("ro.product.model", device_model_str);
 177   return std::string(device_model_str);
 178 }
 179
 180 std::string SysInfo::OperatingSystemVersion() {
 181   int32 major, minor, bugfix;
 182   OperatingSystemVersionNumbers(&major, &minor, &bugfix);
 183   return StringPrintf("%d.%d.%d", major, minor, bugfix);
 184 }
 185
 186 void SysInfo::OperatingSystemVersionNumbers(int32* major_version,
 187                                             int32* minor_version,
 188                                             int32* bugfix_version) {
 189   // Read the version number string out from the properties.
 190   char os_version_str[PROP_VALUE_MAX];
 191   __system_property_get("ro.build.version.release", os_version_str);
 192
 193   // Parse out the numbers.
 194   ParseOSVersionNumbers(os_version_str, major_version, minor_version,
 195                         bugfix_version);
 196 }
 197
 198 int SysInfo::DalvikHeapSizeMB() {
 199   static int heap_size = GetDalvikHeapSizeMB();
 200   return heap_size;
 201 }
 202
 203 int SysInfo::DalvikHeapGrowthLimitMB() {
 204   static int heap_growth_limit = GetDalvikHeapGrowthLimitMB();
 205   return heap_growth_limit;
 206 }
 207
 208 static base::LazyInstance<
 209     base::internal::LazySysInfoValue<bool,
 210         android::SysUtils::IsLowEndDeviceFromJni> >::Leaky
 211     g_lazy_low_end_device = LAZY_INSTANCE_INITIALIZER;
 212
 213 bool SysInfo::IsLowEndDevice() {
 214   return g_lazy_low_end_device.Get().value();
 215 }
 216
 217
 218 }  // namespace base