Add lock to prevent race on SysTimeFromTimeStruct

base/time/time_posix.cc

Index: base/time/time_posix.cc
diff --git a/base/time/time_posix.cc b/base/time/time_posix.cc
index b5b8213846dbbd282b7aab63c681dc15f6a9ae33..fb1fd1fe14c382ec15d603bf66bbcbf6fe3de153 100644
--- a/base/time/time_posix.cc
+++ b/base/time/time_posix.cc
@@ -21,13 +21,22 @@
 #include "build/build_config.h"
 
 #if defined(OS_ANDROID)
+#include "base/lazy_instance.h"
 #include "base/os_compat_android.h"
+#include "base/synchronization/lock.h"
 #elif defined(OS_NACL)
 #include "base/os_compat_nacl.h"
 #endif
 
 namespace {
 
+#if defined(OS_ANDROID)

[willchan no longer on Chromium, 2014/08/05 23:14:48]

No need for the OS_ANDROID stuff. This bug isn't Android specific, it applies to
all posix implementations doing an unsynchronized read/write on the TZ global
environment variable.

[bengr, 2014/08/05 23:54:58]

Done.

+// This prevents a crash on traversing the environment global and looking up
+// the 'TZ' variable in libc.
+base::LazyInstance<base::Lock>::Leaky
+  g_sys_time_to_time_struct_lock = LAZY_INSTANCE_INITIALIZER;
+#endif
+
 #if !defined(OS_MACOSX)
 // Define a system-specific SysTime that wraps either to a time_t or
 // a time64_t depending on the host system, and associated convertion.
@@ -36,6 +45,9 @@ namespace {
 typedef time64_t SysTime;
 
 SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
+#if defined(OS_ANDROID)
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
+#endif
   if (is_local)
     return mktime64(timestruct);
   else
@@ -43,6 +55,9 @@ SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
 }
 
 void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
+#if defined(OS_ANDROID)
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
+#endif
   if (is_local)
     localtime64_r(&t, timestruct);
   else