/*
* 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 query function.
*/
__pnacl_real_irt_query_func = (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_wrap_irt_query_func;
}
/* 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);
}