1 /* 2 * Copyright (c) 2012 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 "native_client/src/shared/srpc/nacl_srpc.h" 8 #include "ppapi/native_client/src/untrusted/nacl_ppapi_util/ppapi_srpc_main.h" 9 10 /* 11 * Here be dragons. Beware. 12 * 13 * We need to provide a main so that when this code is compiled with 14 * irt=1, we can invoke NaClSrpcModuleInit. This is not needed when 15 * we compile with irt=0 because the PpapiPluginMain uses SRPC and 16 * will invoke NaClSrpcModuleInit. However, with irt=1, there are two 17 * copies of the SRPC (and platform, and ...) libraries: the 18 * PpapiPluginMain code uses a copy of SRPC in the IRT, and the user 19 * code -- that's us -- has another copy. The two copies have 20 * separate allocators, globals, etc because of the IRT separation, so 21 * that the NaClSrpcModuleInit that is invoked in the IRT will not 22 * initialize the data structures used by the copy in the user code. 23 * 24 * The weak reference to the function __nacl_register_thread_creator 25 * is an IRT implementation-dependent hack. Here's how it works. In 26 * irt_stub, there is a definition for __nacl_register_thread_creator, 27 * so if this code is compiled and linked with irt=1, the weak symbol 28 * will be overridden with a real function, and the tests inside of 29 * main will succeed. If this code is compiled and linked with irt=0, 30 * however, we will not link against irt_stub (-lppapi which is a 31 * linker script which causes libppapi_stub.a to get included, which 32 * includes the code from the src/untrusted/irt_stub directory), and 33 * so the __nacl_register_thread_creator weak symbol will have the 34 * value zero. Voila, we call NaClSrpcModuleInit in the main function 35 * below if the scons command invocation had irt=1 set, and we will 36 * leave it to PpapiPluginMain to invoke NaClSrpcModuleInit when the 37 * scons invocation had irt=0 set. 38 * 39 * Yes, this could be conditionally linked in via scons magic by 40 * testing the irt bit, avoiding the weak attribute magic. 41 */ 42 43 struct nacl_irt_ppapihook; 44 45 void __nacl_register_thread_creator(const struct nacl_irt_ppapihook *) 46 __attribute__((weak)); 47 48 int main(void) { 49 int rv; 50 51 if (__nacl_register_thread_creator) { 52 if (!NaClSrpcModuleInit()) { 53 return 1; 54 } 55 } 56 57 rv = PpapiPluginMain(); 58 59 if (__nacl_register_thread_creator) { 60 NaClSrpcModuleFini(); 61 } 62 63 return rv; 64 } 65
