Bug 737084 - Do pthread_atfork in jemalloc on mac and android. r=blassey,r=khuey

configure.in

@@ -7233,6 +7233,7 @@ if test "$OS_TARGET" = Android; then
             WRAP_LDFLAGS="${WRAP_LDFLAGS} -Wl,--wrap=dlopen,--wrap=dlclose,--wrap=dlerror,--wrap=dlsym,--wrap=dladdr"
         fi
         WRAP_LDFLAGS="${WRAP_LDFLAGS} -Wl,--wrap=getaddrinfo,--wrap=freeaddrinfo,--wrap=gai_strerror"
+        WRAP_LDFLAGS="${WRAP_LDFLAGS} -Wl,--wrap=fork,--wrap=pthread_atfork"
     fi
 fi
 

memory/jemalloc/jemalloc.c

@@ -1419,13 +1419,8 @@ static
 #endif
 bool		malloc_init_hard(void);
 
-#ifdef MOZ_MEMORY_ANDROID
-void	_malloc_prefork(void);
-void	_malloc_postfork(void);
-#else
 static void	_malloc_prefork(void);
 static void	_malloc_postfork(void);
-#endif
 
 #ifdef MOZ_MEMORY_DARWIN
 /*
@@ -5923,10 +5918,8 @@ MALLOC_OUT:
 #endif
 	}
 
-#if (!defined(MOZ_MEMORY_WINDOWS) && !defined(MOZ_MEMORY_DARWIN) && !defined(MOZ_MEMORY_ANDROID))
+#if !defined(MOZ_MEMORY_WINDOWS)
 	/* Prevent potential deadlock on malloc locks after fork. */
-	/* XXX on Android there is no pthread_atfork, so we specifically
-	   call _malloc_prefork and _malloc_postfork in process_util_linux.cc */
 	pthread_atfork(_malloc_prefork, _malloc_postfork, _malloc_postfork);
 #endif
 
@@ -6849,11 +6842,7 @@ _msize(const void *ptr)
  * is threaded here.
  */
 
-#ifdef MOZ_MEMORY_ANDROID
-void
-#else
 static void
-#endif
 _malloc_prefork(void)
 {
 	unsigned i;
@@ -6871,11 +6860,7 @@ _malloc_prefork(void)
 	malloc_mutex_lock(&huge_mtx);
 }
 
-#ifdef MOZ_MEMORY_ANDROID
-void
-#else
 static void
-#endif
 _malloc_postfork(void)
 {
 	unsigned i;

memory/jemalloc/jemalloc.h

@@ -53,10 +53,6 @@ int	posix_memalign(void **memptr, size_t alignment, size_t size);
 /* Android doesn't have posix_memalign */
 #ifdef MOZ_MEMORY_ANDROID
 int	posix_memalign(void **memptr, size_t alignment, size_t size);
-/* Android < 2.3 doesn't have pthread_atfork, so we need to call these
- * when forking the child process. See bug 680190 */
-void    _malloc_prefork(void);
-void    _malloc_postfork(void);
 #endif
 
 #if defined(MOZ_MEMORY_DARWIN) || defined(MOZ_MEMORY_WINDOWS)

mozglue/android/APKOpen.cpp

@@ -1037,3 +1037,46 @@ ChildProcessInit(int argc, char* argv[])
   return fXRE_InitChildProcess(argc, argv, proctype);
 }
 
+/* Android doesn't have pthread_atfork(), so we need to use our own. */
+struct AtForkFuncs {
+  void (*prepare)(void);
+  void (*parent)(void);
+  void (*child)(void);
+};
+static std::vector<AtForkFuncs> atfork;
+
+extern "C" NS_EXPORT int
+__wrap_pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
+{
+  AtForkFuncs funcs;
+  funcs.prepare = prepare;
+  funcs.parent = parent;
+  funcs.child = child;
+  atfork.push_back(funcs);
+  return 0;
+}
+
+extern "C" NS_EXPORT pid_t
+__wrap_fork(void)
+{
+  pid_t pid;
+  for (std::vector<AtForkFuncs>::reverse_iterator it = atfork.rbegin();
+       it < atfork.rend(); ++it)
+    if (it->prepare)
+      it->prepare();
+
+  switch ((pid = fork())) {
+  case 0:
+    for (std::vector<AtForkFuncs>::iterator it = atfork.begin();
+         it < atfork.end(); ++it)
+      if (it->child)
+        it->child();
+    break;
+  default:
+    for (std::vector<AtForkFuncs>::iterator it = atfork.begin();
+         it < atfork.end(); ++it)
+      if (it->parent)
+        it->parent();
+  }
+  return pid;
+}

mozglue/build/Makefile.in

@@ -84,6 +84,10 @@ endif
 ifeq (android, $(MOZ_WIDGET_TOOLKIT))
 # Add Android specific code
 EXTRA_DSO_LDOPTS += $(ZLIB_LIBS)
+ifdef MOZ_MEMORY
+# To properly wrap jemalloc's pthread_atfork call.
+EXTRA_DSO_LDOPTS += -Wl,--wrap=pthread_atfork
+endif
 SHARED_LIBRARY_LIBS += $(call EXPAND_LIBNAME_PATH,android,$(DEPTH)/other-licenses/android)
 SHARED_LIBRARY_LIBS += $(call EXPAND_LIBNAME_PATH,android,../android)
 endif