Merge changes I98c9329f,I40936f7b,I09d20ff1

* changes:
  Defer registration of the arc4random fork-detect handler.
  Make getpid work before the main thread is initialized.
  Take the arc4random lock before forking.

4 files changed, 20 insertions, 14 deletions

diff --git a/libc/bionic/getpid.cpp b/libc/bionic/getpid.cpp
index a3d5b35c9..779b1477c 100644
--- a/libc/bionic/getpid.cpp
+++ b/libc/bionic/getpid.cpp
@@ -35,10 +35,12 @@ extern "C" pid_t __getpid();
 pid_t getpid() {
   pthread_internal_t* self = __get_thread();
 
-  // Do we have a valid cached pid?
-  pid_t cached_pid;
-  if (__predict_true(self->get_cached_pid(&cached_pid))) {
-    return cached_pid;
+  if (__predict_true(self)) {
+    // Do we have a valid cached pid?
+    pid_t cached_pid;
+    if (__predict_true(self->get_cached_pid(&cached_pid))) {
+      return cached_pid;
+    }
   }
 
   // We're still in the dynamic linker or we're in the middle of forking, so ask the kernel.
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 0c9e87b8b..2070c9c82 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -41,13 +41,14 @@
 #include <sys/time.h>
 #include <unistd.h>
 
+#include "private/KernelArgumentBlock.h"
+#include "private/WriteProtected.h"
 #include "private/bionic_auxv.h"
 #include "private/bionic_globals.h"
 #include "private/bionic_ssp.h"
 #include "private/bionic_tls.h"
-#include "private/KernelArgumentBlock.h"
 #include "private/libc_logging.h"
-#include "private/WriteProtected.h"
+#include "private/thread_private.h"
 #include "pthread_internal.h"
 
 extern "C" abort_msg_t** __abort_message_ptr;
@@ -108,6 +109,11 @@ static void __check_max_thread_id() {
 }
 #endif
 
+static void arc4random_fork_handler() {
+  _rs_forked = 1;
+  _thread_arc4_lock();
+}
+
 void __libc_init_common(KernelArgumentBlock& args) {
   // Initialize various globals.
   environ = args.envp;
@@ -123,6 +129,9 @@ void __libc_init_common(KernelArgumentBlock& args) {
   pthread_internal_t* main_thread = __get_thread();
   __pthread_internal_add(main_thread);
 
+  // Register atfork handlers to take and release the arc4random lock.
+  pthread_atfork(arc4random_fork_handler, _thread_arc4_unlock, _thread_arc4_unlock);
+
   __system_properties_init(); // Requires 'environ'.
 }
 
diff --git a/libc/private/thread_private.h b/libc/private/thread_private.h
index 2e3ac3d97..0081ad020 100644
--- a/libc/private/thread_private.h
+++ b/libc/private/thread_private.h
@@ -50,6 +50,8 @@ __LIBC_HIDDEN__ void    _thread_arc4_unlock(void);
 #define _ARC4_UNLOCK() _thread_arc4_unlock()
 #define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f))
 
+extern volatile sig_atomic_t _rs_forked;
+
 __END_DECLS
 
 #endif /* _THREAD_PRIVATE_H_ */
diff --git a/libc/upstream-openbsd/android/include/arc4random.h b/libc/upstream-openbsd/android/include/arc4random.h
index 96d9c9a26..8d965e0f9 100644
--- a/libc/upstream-openbsd/android/include/arc4random.h
+++ b/libc/upstream-openbsd/android/include/arc4random.h
@@ -49,13 +49,7 @@ _getentropy_fail(void)
 	raise(SIGKILL);
 }
 
-static volatile sig_atomic_t _rs_forked;
-
-static inline void
-_rs_forkhandler(void)
-{
-	_rs_forked = 1;
-}
+volatile sig_atomic_t _rs_forked;
 
 static inline void
 _rs_forkdetect(void)
@@ -90,6 +84,5 @@ _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
 	prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, *rsxp, sizeof(**rsxp),
 	    "arc4random _rsx structure");
 
-	_ARC4_ATFORK(_rs_forkhandler);
 	return (0);
 }