| /* |
| * Copyright (c) 2012 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 "native_client/src/include/elf32.h" |
| #include "native_client/src/include/elf_auxv.h" |
| #include "native_client/src/include/nacl_macros.h" |
| #include "native_client/src/untrusted/nacl/nacl_startup.h" |
| #include "ppapi/native_client/src/untrusted/pnacl_irt_shim/shim_ppapi.h" |
| |
| |
| /* |
| * This is the true entry point for untrusted code. |
| * See nacl_startup.h for the layout at the argument pointer. |
| */ |
| void _pnacl_wrapper_start(uint32_t *info) { |
| Elf32_auxv_t *auxv = nacl_startup_auxv(info); |
| |
| Elf32_auxv_t *entry = NULL; |
| for (Elf32_auxv_t *av = auxv; av->a_type != AT_NULL; ++av) { |
| if (av->a_type == AT_SYSINFO) { |
| entry = av; |
| break; |
| } |
| } |
| |
| if (entry != NULL) { |
| /* |
| * Save the real irt interface. |
| */ |
| __pnacl_real_irt_interface = (TYPE_nacl_irt_query) entry->a_un.a_val; |
| |
| /* |
| * Overwrite the auxv slot with the pnacl IRT shim query function. |
| */ |
| entry->a_type = AT_SYSINFO; |
| entry->a_un.a_val = (uintptr_t) __pnacl_irt_interface_wrapper; |
| } |
| |
| /* If entry is NULL still allow startup to continue. It may be the case |
| * that the IRT was not actually used (e.g., for some commandline tests). |
| * For newlib, we can tell that the IRT isn't used when libnacl_sys_private.a |
| * is in the bitcode link line. However, glibc does not use |
| * libnacl_sys_private, so that would not work. We could look for -lppapi |
| * in the bitcode link line, but looking at the bitcode link line |
| * seems brittle (what if the bitcode link was separated from translation). |
| * Thus we always wrap _start, even if there is no IRT auxv entry. |
| */ |
| |
| /* |
| * Call the user entry point function. It should not return. |
| * TODO(sehr): Find a way to ensure this is invoked via a tail call. |
| */ |
| _start(info); |
| } |