Non-SFI mode: Add Linux asynchronous signal support

src/nonsfi/linux/linux_pthread_private.c

 /*
  * Copyright 2014 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <errno.h>
 
 #include "native_client/src/nonsfi/linux/linux_syscall_defines.h"
 #include "native_client/src/nonsfi/linux/linux_syscall_structs.h"
 #include "native_client/src/nonsfi/linux/linux_syscall_wrappers.h"
 #include "native_client/src/nonsfi/linux/linux_sys_private.h"
 #include "native_client/src/public/linux_syscalls/sched.h"
 #include "native_client/src/public/linux_syscalls/sys/syscall.h"
 #include "native_client/src/untrusted/nacl/nacl_irt.h"
 #include "native_client/src/untrusted/nacl/nacl_thread.h"
 #include "native_client/src/untrusted/pthread/pthread_internal.h"
 
 /* Convert a return value of a Linux syscall to the one of an IRT call. */
 static uint32_t irt_return_call(uintptr_t result) {
   if (linux_is_error_result(result))
     return -result;
   return 0;
 }
 
 static int nacl_irt_thread_create(void (*start_func)(void), void *stack,
-                                  void *thread_ptr) {
+                                  void *thread_ptr,
+                                  nacl_irt_tid_t *child_tid) {
   /*
    * We do not use CLONE_CHILD_CLEARTID as we do not want any
    * non-private futex signaling. Also, NaCl ABI does not require us
    * to signal the futex on stack_flag.
    */
   int flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
-               CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS);
+               CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS |
+               CLONE_PARENT_SETTID);
   /*
    * linux_clone_wrapper expects start_func's type is "int (*)(void *)".
    * Although |start_func| has type "void (*)(void)", the type mismatching
    * will not cause a problem. Passing a dummy |arg| (= 0) does nothing there.
    * Also, start_func will never return.
    */
   return irt_return_call(linux_clone_wrapper(
       (uintptr_t) start_func, /* arg */ 0, flags, stack,
-      /* ptid */ NULL, thread_ptr, /* ctid */ NULL));
+      child_tid, thread_ptr, /* ctid */ NULL));
 }
 
 static void nacl_irt_thread_exit(int32_t *stack_flag) {
   /*
    * We fill zero to stack_flag by ourselves instead of relying
    * on CLONE_CHILD_CLEARTID. We do everything in the following inline
    * assembly because we need to make sure we will never touch stack.
    *
    * We will set the stack pointer to zero at the beginning of the
    * assembly code just in case an async signal arrives after setting
@@ skipping 19 matching lines @@
 #else
 # error Unsupported architecture
 #endif
 }
 
 static int nacl_irt_thread_nice(const int nice) {
   return 0;
 }
 
 void __nc_initialize_interfaces(void) {
-  const struct nacl_irt_thread init = {
+  const struct nacl_irt_thread_v0_2 init = {
     nacl_irt_thread_create,
     nacl_irt_thread_exit,
     nacl_irt_thread_nice,
   };
   __libnacl_irt_thread = init;
 }