[NaCl SDK} Add ppapi_stub for bionic

Bionic uses a different loader which requires a different ppapi_stub.
This implementaion is for the experimental bionic build only.

BUG=none
R=binji@chromium.org

See related issue to re-merge with GYP/GN
https://code.google.com/p/chromium/issues/detail?id=368779

Review URL: https://codereview.chromium.org/268493004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267549 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 146 insertions, 0 deletions

diff --git a/native_client_sdk/src/libraries/ppapi_stub/library.dsc b/native_client_sdk/src/libraries/ppapi_stub/library.dsc
new file mode 100644
index 0000000..fcb15cf
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_stub/library.dsc
@@ -0,0 +1,19 @@
+{
+  'TOOLS': ['bionic'],
+  'SEARCH': [
+      '.',
+  ],
+  'TARGETS': [
+    {
+      'NAME' : 'ppapi_stub',
+      'TYPE' : 'lib',
+      'SOURCES' : [
+        'main.c',
+        'ppapi_main.c',
+      ],
+    }
+  ],
+  'DEST': 'src',
+  'NAME': 'ppapi_stub',
+}
+
diff --git a/native_client_sdk/src/libraries/ppapi_stub/main.c b/native_client_sdk/src/libraries/ppapi_stub/main.c
new file mode 100644
index 0000000..c1428bc
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_stub/main.c
@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2014 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * An application that doesn't define its own main but links in -lppapi
+ * gets this one.  A plugin may instead have its own main that calls
+ * PpapiPluginMain (or PpapiPluginStart) after doing some other setup.
+ */
+
+int PpapiPluginMain();
+
+int main(void) {
+  return PpapiPluginMain();
+}
diff --git a/native_client_sdk/src/libraries/ppapi_stub/ppapi_main.c b/native_client_sdk/src/libraries/ppapi_stub/ppapi_main.c
new file mode 100644
index 0000000..be540b6
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_stub/ppapi_main.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2014 The Chromium 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 <pthread.h>
+
+#include "irt_syscalls.h"
+#include "ppapi/c/pp_module.h"
+#include "ppapi/c/ppp.h"
+
+struct PP_StartFunctions {
+  int32_t (*PPP_InitializeModule)(PP_Module module_id,
+                                  PPB_GetInterface get_browser_interface);
+  void (*PPP_ShutdownModule)();
+  const void* (*PPP_GetInterface)(const char* interface_name);
+};
+
+struct PP_ThreadFunctions {
+  /*
+   * This is a cut-down version of pthread_create()/pthread_join().
+   * We omit thread creation attributes and the thread's return value.
+   *
+   * We use uintptr_t as the thread ID type because pthread_t is not
+   * part of the stable ABI; a user thread library might choose an
+   * arbitrary size for its own pthread_t.
+   */
+  int (*thread_create)(uintptr_t* tid,
+                       void (*func)(void* thread_argument),
+                       void* thread_argument);
+  int (*thread_join)(uintptr_t tid);
+};
+
+#define NACL_IRT_PPAPIHOOK_v0_1 "nacl-irt-ppapihook-0.1"
+struct nacl_irt_ppapihook {
+  int (*ppapi_start)(const struct PP_StartFunctions*);
+  void (*ppapi_register_thread_creator)(const struct PP_ThreadFunctions*);
+};
+
+
+static int thread_create(uintptr_t *tid,
+                         void (*func)(void *thread_argument),
+                         void *thread_argument) {
+  /*
+   * We know that newlib and glibc use a small pthread_t type, so we
+   * do not need to wrap pthread_t values.
+   */
+  return pthread_create((pthread_t *) tid, NULL,
+                        (void *(*)(void *thread_argument)) func,
+                        thread_argument);
+}
+
+static int thread_join(uintptr_t tid) {
+  return pthread_join((pthread_t) tid, NULL);
+}
+
+/*
+ * These are dangling references to functions that the application must define.
+ */
+static const struct PP_StartFunctions ppapi_app_start_callbacks = {
+  PPP_InitializeModule,
+  PPP_ShutdownModule,
+  PPP_GetInterface
+};
+
+const static struct PP_ThreadFunctions thread_funcs = {
+  thread_create,
+  thread_join
+};
+
+static void fatal_error(const char *message) {
+  write(2, message, strlen(message));
+  _exit(127);
+}
+
+/*
+ * We cannot tell at link time whether the application uses PPB_Audio,
+ * because of the way that PPAPI is defined via runtime interface
+ * query rather than a set of static functions.  This means that we
+ * register the audio thread functions unconditionally.  This adds the
+ * small overhead of pulling in pthread_create() even if the
+ * application does not use PPB_Audio or libpthread.
+ *
+ * If an application developer wants to avoid that cost, they can
+ * override this function with an empty definition.
+ */
+void __nacl_register_thread_creator(const struct nacl_irt_ppapihook *hooks) {
+  hooks->ppapi_register_thread_creator(&thread_funcs);
+}
+
+int PpapiPluginStart(const struct PP_StartFunctions *funcs) {
+  struct nacl_irt_ppapihook hooks;
+  if (sizeof(hooks) != __nacl_irt_query(NACL_IRT_PPAPIHOOK_v0_1,
+                                        &hooks, sizeof(hooks))) {
+    fatal_error("PpapiPluginStart: PPAPI hooks not found\n");
+  }
+
+  __nacl_register_thread_creator(&hooks);
+  return hooks.ppapi_start(funcs);
+}
+
+
+/*
+ * The application's main (or the one supplied in this library) calls this
+ * to start the PPAPI world.
+ */
+int PpapiPluginMain(void) {
+  return PpapiPluginStart(&ppapi_app_start_callbacks);
+}