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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <functional>
#include <unwindstack/Elf.h>
#include <unwindstack/MachineX86.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Memory.h>
#include <unwindstack/RegsX86.h>
#include <unwindstack/UcontextX86.h>
#include <unwindstack/UserX86.h>
namespace unwindstack {
RegsX86::RegsX86() : RegsImpl<uint32_t>(X86_REG_LAST, Location(LOCATION_SP_OFFSET, -4)) {}
ArchEnum RegsX86::Arch() {
return ARCH_X86;
}
uint64_t RegsX86::pc() {
return regs_[X86_REG_PC];
}
uint64_t RegsX86::sp() {
return regs_[X86_REG_SP];
}
void RegsX86::set_pc(uint64_t pc) {
regs_[X86_REG_PC] = static_cast<uint32_t>(pc);
}
void RegsX86::set_sp(uint64_t sp) {
regs_[X86_REG_SP] = static_cast<uint32_t>(sp);
}
bool RegsX86::SetPcFromReturnAddress(Memory* process_memory) {
// Attempt to get the return address from the top of the stack.
uint32_t new_pc;
if (!process_memory->ReadFully(regs_[X86_REG_SP], &new_pc, sizeof(new_pc)) ||
new_pc == regs_[X86_REG_PC]) {
return false;
}
regs_[X86_REG_PC] = new_pc;
return true;
}
void RegsX86::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
fn("eax", regs_[X86_REG_EAX]);
fn("ebx", regs_[X86_REG_EBX]);
fn("ecx", regs_[X86_REG_ECX]);
fn("edx", regs_[X86_REG_EDX]);
fn("ebp", regs_[X86_REG_EBP]);
fn("edi", regs_[X86_REG_EDI]);
fn("esi", regs_[X86_REG_ESI]);
fn("esp", regs_[X86_REG_ESP]);
fn("eip", regs_[X86_REG_EIP]);
}
Regs* RegsX86::Read(const void* user_data) {
const x86_user_regs* user = reinterpret_cast<const x86_user_regs*>(user_data);
RegsX86* regs = new RegsX86();
(*regs)[X86_REG_EAX] = user->eax;
(*regs)[X86_REG_EBX] = user->ebx;
(*regs)[X86_REG_ECX] = user->ecx;
(*regs)[X86_REG_EDX] = user->edx;
(*regs)[X86_REG_EBP] = user->ebp;
(*regs)[X86_REG_EDI] = user->edi;
(*regs)[X86_REG_ESI] = user->esi;
(*regs)[X86_REG_ESP] = user->esp;
(*regs)[X86_REG_EIP] = user->eip;
return regs;
}
void RegsX86::SetFromUcontext(x86_ucontext_t* ucontext) {
// Put the registers in the expected order.
regs_[X86_REG_EDI] = ucontext->uc_mcontext.edi;
regs_[X86_REG_ESI] = ucontext->uc_mcontext.esi;
regs_[X86_REG_EBP] = ucontext->uc_mcontext.ebp;
regs_[X86_REG_ESP] = ucontext->uc_mcontext.esp;
regs_[X86_REG_EBX] = ucontext->uc_mcontext.ebx;
regs_[X86_REG_EDX] = ucontext->uc_mcontext.edx;
regs_[X86_REG_ECX] = ucontext->uc_mcontext.ecx;
regs_[X86_REG_EAX] = ucontext->uc_mcontext.eax;
regs_[X86_REG_EIP] = ucontext->uc_mcontext.eip;
}
Regs* RegsX86::CreateFromUcontext(void* ucontext) {
x86_ucontext_t* x86_ucontext = reinterpret_cast<x86_ucontext_t*>(ucontext);
RegsX86* regs = new RegsX86();
regs->SetFromUcontext(x86_ucontext);
return regs;
}
bool RegsX86::StepIfSignalHandler(uint64_t elf_offset, Elf* elf, Memory* process_memory) {
// Read from elf memory since it is usually more expensive to read from
// process memory.
uint64_t data;
if (!elf->memory()->ReadFully(elf_offset, &data, sizeof(data))) {
return false;
}
if (data == 0x80cd00000077b858ULL) {
// Without SA_SIGINFO set, the return sequence is:
//
// __restore:
// 0x58 pop %eax
// 0xb8 0x77 0x00 0x00 0x00 movl 0x77,%eax
// 0xcd 0x80 int 0x80
//
// SP points at arguments:
// int signum
// struct sigcontext (same format as mcontext)
struct x86_mcontext_t context;
if (!process_memory->ReadFully(regs_[X86_REG_SP] + 4, &context, sizeof(context))) {
return false;
}
regs_[X86_REG_EBP] = context.ebp;
regs_[X86_REG_ESP] = context.esp;
regs_[X86_REG_EBX] = context.ebx;
regs_[X86_REG_EDX] = context.edx;
regs_[X86_REG_ECX] = context.ecx;
regs_[X86_REG_EAX] = context.eax;
regs_[X86_REG_EIP] = context.eip;
return true;
} else if ((data & 0x00ffffffffffffffULL) == 0x0080cd000000adb8ULL) {
// With SA_SIGINFO set, the return sequence is:
//
// __restore_rt:
// 0xb8 0xad 0x00 0x00 0x00 movl 0xad,%eax
// 0xcd 0x80 int 0x80
//
// SP points at arguments:
// int signum
// siginfo*
// ucontext*
// Get the location of the sigcontext data.
uint32_t ptr;
if (!process_memory->ReadFully(regs_[X86_REG_SP] + 8, &ptr, sizeof(ptr))) {
return false;
}
// Only read the portion of the data structure we care about.
x86_ucontext_t x86_ucontext;
if (!process_memory->ReadFully(ptr + 0x14, &x86_ucontext.uc_mcontext, sizeof(x86_mcontext_t))) {
return false;
}
SetFromUcontext(&x86_ucontext);
return true;
}
return false;
}
Regs* RegsX86::Clone() {
return new RegsX86(*this);
}
} // namespace unwindstack
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