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74 lines
2.1 KiB
74 lines
2.1 KiB
/* |
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* Copyright (C) 2013 The Android Open Source Project |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#ifndef KERNEL_ARGUMENT_BLOCK_H |
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#define KERNEL_ARGUMENT_BLOCK_H |
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#include <elf.h> |
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#include <link.h> |
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#include <stdint.h> |
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#include <sys/auxv.h> |
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#include "private/bionic_macros.h" |
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struct abort_msg_t; |
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// When the kernel starts the dynamic linker, it passes a pointer to a block |
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// of memory containing argc, the argv array, the environment variable array, |
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// and the array of ELF aux vectors. This class breaks that block up into its |
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// constituents for easy access. |
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class KernelArgumentBlock { |
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public: |
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KernelArgumentBlock(void* raw_args) { |
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uintptr_t* args = reinterpret_cast<uintptr_t*>(raw_args); |
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argc = static_cast<int>(*args); |
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argv = reinterpret_cast<char**>(args + 1); |
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envp = argv + argc + 1; |
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// Skip over all environment variable definitions to find the aux vector. |
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// The end of the environment block is marked by a NULL pointer. |
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char** p = envp; |
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while (*p != NULL) { |
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++p; |
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} |
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++p; // Skip the NULL itself. |
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auxv = reinterpret_cast<ElfW(auxv_t)*>(p); |
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} |
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// Similar to ::getauxval but doesn't require the libc global variables to be set up, |
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// so it's safe to call this really early on. |
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unsigned long getauxval(unsigned long type) { |
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for (ElfW(auxv_t)* v = auxv; v->a_type != AT_NULL; ++v) { |
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if (v->a_type == type) { |
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return v->a_un.a_val; |
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} |
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} |
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return 0; |
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} |
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int argc; |
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char** argv; |
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char** envp; |
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ElfW(auxv_t)* auxv; |
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abort_msg_t** abort_message_ptr; |
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private: |
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DISALLOW_COPY_AND_ASSIGN(KernelArgumentBlock); |
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}; |
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#endif // KERNEL_ARGUMENT_BLOCK_H
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