Enable SysInfo::AmountOfPhysicalMemory to be called from within the Linux sandbox.

Trigger caching of SysInfo::AmountOfPhysicalMemory in PreSandboxInit() to enable
it to be called by the renderer process after the sandbox is sealed.

BUG=312241

Review URL: https://codereview.chromium.org/28833002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231613 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 66 insertions, 35 deletions

diff --git a/base/sys_info_linux.cc b/base/sys_info_linux.cc
index acc4771..c862145 100644
--- a/base/sys_info_linux.cc
+++ b/base/sys_info_linux.cc
@@ -7,6 +7,7 @@
 #include <limits>
 
 #include "base/file_util.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 
@@ -22,52 +23,34 @@ int64 AmountOfMemory(int pages_name) {
   return static_cast<int64>(pages) * page_size;
 }
 
-}  // namespace
-
-namespace base {
-
-// static
-int64 SysInfo::AmountOfPhysicalMemory() {
-  return AmountOfMemory(_SC_PHYS_PAGES);
-}
-
-// static
-int64 SysInfo::AmountOfAvailablePhysicalMemory() {
-  return AmountOfMemory(_SC_AVPHYS_PAGES);
-}
+size_t MaxSharedMemorySize() {
+  std::string contents;
+  base::ReadFileToString(base::FilePath("/proc/sys/kernel/shmmax"), &contents);
+  DCHECK(!contents.empty());
+  if (!contents.empty() && contents[contents.length() - 1] == '\n') {
+    contents.erase(contents.length() - 1);
+  }
 
-// static
-size_t SysInfo::MaxSharedMemorySize() {
-  static int64 limit;
-  static bool limit_valid = false;
-  if (!limit_valid) {
-    std::string contents;
-    ReadFileToString(FilePath("/proc/sys/kernel/shmmax"), &contents);
-    DCHECK(!contents.empty());
-    if (!contents.empty() && contents[contents.length() - 1] == '\n') {
-      contents.erase(contents.length() - 1);
-    }
-    if (base::StringToInt64(contents, &limit)) {
-      DCHECK(limit >= 0);
-      DCHECK(static_cast<uint64>(limit) <= std::numeric_limits<size_t>::max());
-      limit_valid = true;
-    } else {
-      NOTREACHED();
-      return 0;
-    }
+  int64 limit;
+  if (!base::StringToInt64(contents, &limit)) {
+    limit = 0;
   }
+  if (limit < 0 ||
+      static_cast<uint64>(limit) > std::numeric_limits<size_t>::max()) {
+    limit = 0;
+  }
+  DCHECK(limit > 0);
   return static_cast<size_t>(limit);
 }
 
-// static
-std::string SysInfo::CPUModelName() {
+std::string CPUModelName() {
 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARMEL)
   const char kCpuModelPrefix[] = "Hardware";
 #else
   const char kCpuModelPrefix[] = "model name";
 #endif
   std::string contents;
-  ReadFileToString(FilePath("/proc/cpuinfo"), &contents);
+  base::ReadFileToString(base::FilePath("/proc/cpuinfo"), &contents);
   DCHECK(!contents.empty());
   if (!contents.empty()) {
     std::istringstream iss(contents);
@@ -82,4 +65,52 @@ std::string SysInfo::CPUModelName() {
   return std::string();
 }
 
+class LazySysInfo {
+ public:
+  LazySysInfo()
+      : kPhysicalMemory_(AmountOfMemory(_SC_PHYS_PAGES)),
+        kMaxSharedMemorySize_(MaxSharedMemorySize()),
+        kCpuModelName_(CPUModelName()) { }
+
+  ~LazySysInfo() { }
+
+  int64 physical_memory() { return kPhysicalMemory_; }
+  size_t max_shared_memory_size() { return kMaxSharedMemorySize_; }
+  std::string cpu_model_name() { return kCpuModelName_; }
+
+ private:
+  const int64 kPhysicalMemory_;
+  const size_t kMaxSharedMemorySize_;
+  const std::string kCpuModelName_;
+
+  DISALLOW_COPY_AND_ASSIGN(LazySysInfo);
+};
+
+base::LazyInstance<LazySysInfo>::Leaky
+    g_lazy_sys_info = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+namespace base {
+
+// static
+int64 SysInfo::AmountOfAvailablePhysicalMemory() {
+  return AmountOfMemory(_SC_AVPHYS_PAGES);
+}
+
+// static
+int64 SysInfo::AmountOfPhysicalMemory() {
+  return g_lazy_sys_info.Get().physical_memory();
+}
+
+// static
+size_t SysInfo::MaxSharedMemorySize() {
+  return g_lazy_sys_info.Get().max_shared_memory_size();
+}
+
+// static
+std::string SysInfo::CPUModelName() {
+  return g_lazy_sys_info.Get().cpu_model_name();
+}
+
 }  // namespace base