63fbb233cb
Correct the comment, and remove the unused functionality. getauxval(3) does now set errno to let you know it failed to find anything, but since none of this function's callers care anyway it seems safer to leave errno untouched until we actually have a demonstrated need for it. Bug: https://code.google.com/p/android/issues/detail?id=198111 Change-Id: I232a42dc5a02c8faab94c7d69bef610408276c23
75 lines
2.1 KiB
C++
75 lines
2.1 KiB
C++
/*
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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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