1/*
2 * Copyright (c) 2014 The Chromium Authors. All rights reserved.
3 * Use of this source code is governed by a BSD-style license that can be
4 * found in the LICENSE file.
5 */
6
7#include <pthread.h>
8
9#include "irt_syscalls.h"
10#include "ppapi/c/pp_module.h"
11#include "ppapi/c/ppp.h"
12
13struct PP_StartFunctions {
14  int32_t (*PPP_InitializeModule)(PP_Module module_id,
15                                  PPB_GetInterface get_browser_interface);
16  void (*PPP_ShutdownModule)();
17  const void* (*PPP_GetInterface)(const char* interface_name);
18};
19
20struct PP_ThreadFunctions {
21  /*
22   * This is a cut-down version of pthread_create()/pthread_join().
23   * We omit thread creation attributes and the thread's return value.
24   *
25   * We use uintptr_t as the thread ID type because pthread_t is not
26   * part of the stable ABI; a user thread library might choose an
27   * arbitrary size for its own pthread_t.
28   */
29  int (*thread_create)(uintptr_t* tid,
30                       void (*func)(void* thread_argument),
31                       void* thread_argument);
32  int (*thread_join)(uintptr_t tid);
33};
34
35#define NACL_IRT_PPAPIHOOK_v0_1 "nacl-irt-ppapihook-0.1"
36struct nacl_irt_ppapihook {
37  int (*ppapi_start)(const struct PP_StartFunctions*);
38  void (*ppapi_register_thread_creator)(const struct PP_ThreadFunctions*);
39};
40
41
42static int thread_create(uintptr_t *tid,
43                         void (*func)(void *thread_argument),
44                         void *thread_argument) {
45  /*
46   * We know that newlib and glibc use a small pthread_t type, so we
47   * do not need to wrap pthread_t values.
48   */
49  return pthread_create((pthread_t *) tid, NULL,
50                        (void *(*)(void *thread_argument)) func,
51                        thread_argument);
52}
53
54static int thread_join(uintptr_t tid) {
55  return pthread_join((pthread_t) tid, NULL);
56}
57
58/*
59 * These are dangling references to functions that the application must define.
60 */
61static const struct PP_StartFunctions ppapi_app_start_callbacks = {
62  PPP_InitializeModule,
63  PPP_ShutdownModule,
64  PPP_GetInterface
65};
66
67const static struct PP_ThreadFunctions thread_funcs = {
68  thread_create,
69  thread_join
70};
71
72static void fatal_error(const char *message) {
73  write(2, message, strlen(message));
74  _exit(127);
75}
76
77/*
78 * We cannot tell at link time whether the application uses PPB_Audio,
79 * because of the way that PPAPI is defined via runtime interface
80 * query rather than a set of static functions.  This means that we
81 * register the audio thread functions unconditionally.  This adds the
82 * small overhead of pulling in pthread_create() even if the
83 * application does not use PPB_Audio or libpthread.
84 *
85 * If an application developer wants to avoid that cost, they can
86 * override this function with an empty definition.
87 */
88void __nacl_register_thread_creator(const struct nacl_irt_ppapihook *hooks) {
89  hooks->ppapi_register_thread_creator(&thread_funcs);
90}
91
92int PpapiPluginStart(const struct PP_StartFunctions *funcs) {
93  struct nacl_irt_ppapihook hooks;
94  if (sizeof(hooks) != __nacl_irt_query(NACL_IRT_PPAPIHOOK_v0_1,
95                                        &hooks, sizeof(hooks))) {
96    fatal_error("PpapiPluginStart: PPAPI hooks not found\n");
97  }
98
99  __nacl_register_thread_creator(&hooks);
100  return hooks.ppapi_start(funcs);
101}
102
103
104/*
105 * The application's main (or the one supplied in this library) calls this
106 * to start the PPAPI world.
107 */
108int PpapiPluginMain(void) {
109  return PpapiPluginStart(&ppapi_app_start_callbacks);
110}
111