ppapi/native_client/src/untrusted/pnacl_irt_shim/shim_ppapi.c

   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 "ppapi/native_client/src/untrusted/pnacl_irt_shim/shim_ppapi.h"
   8
   9 #include <string.h>
  10 #include "native_client/src/untrusted/irt/irt.h"
  11 #include "ppapi/nacl_irt/public/irt_ppapi.h"
  12 #include "ppapi/native_client/src/shared/ppapi_proxy/ppruntime.h"
  13 #include "ppapi/native_client/src/untrusted/pnacl_irt_shim/irt_shim_ppapi.h"
  14 #include "ppapi/native_client/src/untrusted/pnacl_irt_shim/pnacl_shim.h"
  15
  16 /* Use local strcmp to avoid dependency on libc. */
  17 static int mystrcmp(const char* s1, const char *s2) {
  18   while((*s1 && *s2) && (*s1++ == *s2++));
  19   return *(--s1) - *(--s2);
  20 }
  21
  22 TYPE_nacl_irt_query __pnacl_real_irt_query_func = NULL;
  23
  24 size_t __pnacl_wrap_irt_query_func(const char *interface_ident,
  25                                      void *table, size_t tablesize) {
  26   /*
  27    * Note there is a benign race in initializing the wrapper.
  28    * We build the "hook" structure by copying from the IRT's hook and then
  29    * writing our wrapper for the ppapi method.  Two threads may end up
  30    * attempting to do this simultaneously, which should not be a problem,
  31    * as they are writing the same values.
  32    */
  33   if (0 != mystrcmp(interface_ident, NACL_IRT_PPAPIHOOK_v0_1)) {
  34     /*
  35      * The interface is not wrapped, so use the real interface.
  36      */
  37     return (*__pnacl_real_irt_query_func)(interface_ident, table, tablesize);
  38   }
  39 #ifndef PNACL_SHIM_AOT
  40   /*
  41    * For PNaCl in-the-browser, redirect to using
  42    * NACL_IRT_PPAPIHOOK_PNACL_PRIVATE_v0_1 instead of NACL_IRT_PPAPIHOOK_v0_1.
  43    */
  44   return (*__pnacl_real_irt_query_func)(NACL_IRT_PPAPIHOOK_PNACL_PRIVATE_v0_1,
  45                                         table, tablesize);
  46 #else
  47   /*
  48    * For offline generated nexes, avoid depending on the private
  49    * NACL_IRT_PPAPIHOOK_PNACL_PRIVATE_v0_1 interface, and just do the
  50    * overriding here manually.
  51    */
  52   struct nacl_irt_ppapihook real_irt_ppapi_hook;
  53   if ((*__pnacl_real_irt_query_func)(NACL_IRT_PPAPIHOOK_v0_1,
  54                                      &real_irt_ppapi_hook,
  55                                      sizeof real_irt_ppapi_hook) !=
  56       sizeof real_irt_ppapi_hook) {
  57     return 0;
  58   }
  59   real_irt_ppapi_start = real_irt_ppapi_hook.ppapi_start;
  60   /*
  61    * Copy the interface structure into the client.
  62    */
  63   struct nacl_irt_ppapihook *dest = table;
  64   if (sizeof *dest <= tablesize) {
  65     dest->ppapi_start = irt_shim_ppapi_start;
  66     dest->ppapi_register_thread_creator =
  67         real_irt_ppapi_hook.ppapi_register_thread_creator;
  68     return sizeof *dest;
  69   }
  70   return 0;
  71 #endif
  72 }