142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes/* 242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * Copyright (C) 2013 The Android Open Source Project 342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * 442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * Licensed under the Apache License, Version 2.0 (the "License"); 542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * you may not use this file except in compliance with the License. 642b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * You may obtain a copy of the License at 742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * 842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * http://www.apache.org/licenses/LICENSE-2.0 942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * 1042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * Unless required by applicable law or agreed to in writing, software 1142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * distributed under the License is distributed on an "AS IS" BASIS, 1242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 1342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * See the License for the specific language governing permissions and 1442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes * limitations under the License. 1542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes */ 1642b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 1742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#ifndef KERNEL_ARGUMENT_BLOCK_H 1842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#define KERNEL_ARGUMENT_BLOCK_H 1942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 2042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#include <elf.h> 210266ae5f884d72da58f33a072e865ba131234a5eElliott Hughes#include <link.h> 2242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#include <stdint.h> 2342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#include <sys/auxv.h> 2442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 258eac9af24ea7e570e0b297bcd6ac8a46ba3ecc39Elliott Hughes#include "private/bionic_macros.h" 268eac9af24ea7e570e0b297bcd6ac8a46ba3ecc39Elliott Hughes 270d787c1fa18c6a1f29ef9840e28a68cf077be1deElliott Hughesstruct abort_msg_t; 280d787c1fa18c6a1f29ef9840e28a68cf077be1deElliott Hughes 2942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes// When the kernel starts the dynamic linker, it passes a pointer to a block 3042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes// of memory containing argc, the argv array, the environment variable array, 3142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes// and the array of ELF aux vectors. This class breaks that block up into its 3242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes// constituents for easy access. 3342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughesclass KernelArgumentBlock { 3442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes public: 3542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes KernelArgumentBlock(void* raw_args) { 36c620059479c47a78d57086d73726c9adc2f337adElliott Hughes uintptr_t* args = reinterpret_cast<uintptr_t*>(raw_args); 3742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes argc = static_cast<int>(*args); 3842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes argv = reinterpret_cast<char**>(args + 1); 3942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes envp = argv + argc + 1; 4042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 4142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes // Skip over all environment variable definitions to find aux vector. 4242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes // The end of the environment block is marked by two NULL pointers. 4342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes char** p = envp; 4442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes while (*p != NULL) { 4542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes ++p; 4642b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 4742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes ++p; // Skip second NULL; 4842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 490266ae5f884d72da58f33a072e865ba131234a5eElliott Hughes auxv = reinterpret_cast<ElfW(auxv_t)*>(p); 5042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 5142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 5242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes // Similar to ::getauxval but doesn't require the libc global variables to be set up, 5342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes // so it's safe to call this really early on. This function also lets you distinguish 5442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes // between the inability to find the given type and its value just happening to be 0. 5542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes unsigned long getauxval(unsigned long type, bool* found_match = NULL) { 560266ae5f884d72da58f33a072e865ba131234a5eElliott Hughes for (ElfW(auxv_t)* v = auxv; v->a_type != AT_NULL; ++v) { 5742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes if (v->a_type == type) { 5842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes if (found_match != NULL) { 5942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes *found_match = true; 6042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 6142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes return v->a_un.a_val; 6242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 6342b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 6442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes if (found_match != NULL) { 6542b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes *found_match = false; 6642b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 6742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes return 0; 6842b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes } 6942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 7042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes int argc; 7142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes char** argv; 7242b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes char** envp; 730266ae5f884d72da58f33a072e865ba131234a5eElliott Hughes ElfW(auxv_t)* auxv; 7442b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 750d787c1fa18c6a1f29ef9840e28a68cf077be1deElliott Hughes abort_msg_t** abort_message_ptr; 760d787c1fa18c6a1f29ef9840e28a68cf077be1deElliott Hughes 7742b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes private: 788eac9af24ea7e570e0b297bcd6ac8a46ba3ecc39Elliott Hughes DISALLOW_COPY_AND_ASSIGN(KernelArgumentBlock); 7942b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes}; 8042b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes 8142b2c6a5eed5e4ef35315b8cd32d1355f12a69b6Elliott Hughes#endif // KERNEL_ARGUMENT_BLOCK_H 82