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..27438144376eb139d90555247cc433a981f5ad02 100644
--- a/base/time/time_posix.cc
+++ b/base/time/time_posix.cc
@@ -16,8 +16,10 @@
 #include <ostream>
 
 #include "base/basictypes.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/port.h"
+#include "base/synchronization/lock.h"
 #include "build/build_config.h"
 
 #if defined(OS_ANDROID)
@@ -28,6 +30,11 @@
 
 namespace {
 
+// This prevents a crash on traversing the environment global and looking up
+// the 'TZ' variable in libc.

[willchan no longer on Chromium, 2014/08/06 20:43:24]

Please update this to reference the bug so people can understand what's going
on.

[bengr, 2014/08/07 18:28:30]

Done.

+base::LazyInstance<base::Lock>::Leaky
+    g_sys_time_to_time_struct_lock = LAZY_INSTANCE_INITIALIZER;
+
 #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 +43,7 @@ namespace {
 typedef time64_t SysTime;
 
 SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
   if (is_local)
     return mktime64(timestruct);
   else
@@ -43,6 +51,7 @@ SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
 }
 
 void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
   if (is_local)
     localtime64_r(&t, timestruct);
   else
@@ -53,6 +62,7 @@ void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
 typedef time_t SysTime;
 
 SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
   if (is_local)
     return mktime(timestruct);
   else
@@ -60,6 +70,7 @@ SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
 }
 
 void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
+  base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
   if (is_local)
     localtime_r(&t, timestruct);
   else