/*
* 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 <assert.h>
#include <elf.h>
#include <stdint.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <vector>
#include "Elf.h"
#include "ElfInterface.h"
#include "Machine.h"
#include "MapInfo.h"
#include "Regs.h"
#include "User.h"
template <typename AddressType>
uint64_t RegsTmpl<AddressType>::GetRelPc(Elf* elf, const MapInfo* map_info) {
uint64_t load_bias = 0;
if (elf->valid()) {
load_bias = elf->interface()->load_bias();
}
return pc_ - map_info->start + load_bias + map_info->elf_offset;
}
template <typename AddressType>
bool RegsTmpl<AddressType>::GetReturnAddressFromDefault(Memory* memory, uint64_t* value) {
switch (return_loc_.type) {
case LOCATION_REGISTER:
assert(return_loc_.value < total_regs_);
*value = regs_[return_loc_.value];
return true;
case LOCATION_SP_OFFSET:
AddressType return_value;
if (!memory->Read(sp_ + return_loc_.value, &return_value, sizeof(return_value))) {
return false;
}
*value = return_value;
return true;
case LOCATION_UNKNOWN:
default:
return false;
}
}
RegsArm::RegsArm() : RegsTmpl<uint32_t>(ARM_REG_LAST, ARM_REG_SP,
Location(LOCATION_REGISTER, ARM_REG_LR)) {
}
uint64_t RegsArm::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
if (!elf->valid()) {
return rel_pc;
}
uint64_t load_bias = elf->interface()->load_bias();
if (rel_pc < load_bias) {
return rel_pc;
}
uint64_t adjusted_rel_pc = rel_pc - load_bias;
if (adjusted_rel_pc < 5) {
return rel_pc;
}
if (adjusted_rel_pc & 1) {
// This is a thumb instruction, it could be 2 or 4 bytes.
uint32_t value;
if (rel_pc < 5 || !elf->memory()->Read(adjusted_rel_pc - 5, &value, sizeof(value)) ||
(value & 0xe000f000) != 0xe000f000) {
return rel_pc - 2;
}
}
return rel_pc - 4;
}
RegsArm64::RegsArm64() : RegsTmpl<uint64_t>(ARM64_REG_LAST, ARM64_REG_SP,
Location(LOCATION_REGISTER, ARM64_REG_LR)) {
}
uint64_t RegsArm64::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
if (!elf->valid()) {
return rel_pc;
}
if (rel_pc < 4) {
return rel_pc;
}
return rel_pc - 4;
}
RegsX86::RegsX86() : RegsTmpl<uint32_t>(X86_REG_LAST, X86_REG_SP,
Location(LOCATION_SP_OFFSET, -4)) {
}
uint64_t RegsX86::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
if (!elf->valid()) {
return rel_pc;
}
if (rel_pc == 0) {
return 0;
}
return rel_pc - 1;
}
RegsX86_64::RegsX86_64() : RegsTmpl<uint64_t>(X86_64_REG_LAST, X86_64_REG_SP,
Location(LOCATION_SP_OFFSET, -8)) {
}
uint64_t RegsX86_64::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
if (!elf->valid()) {
return rel_pc;
}
if (rel_pc == 0) {
return 0;
}
return rel_pc - 1;
}
static Regs* ReadArm(void* remote_data) {
arm_user_regs* user = reinterpret_cast<arm_user_regs*>(remote_data);
RegsArm* regs = new RegsArm();
memcpy(regs->RawData(), &user->regs[0], ARM_REG_LAST * sizeof(uint32_t));
regs->set_pc(user->regs[ARM_REG_PC]);
regs->set_sp(user->regs[ARM_REG_SP]);
return regs;
}
static Regs* ReadArm64(void* remote_data) {
arm64_user_regs* user = reinterpret_cast<arm64_user_regs*>(remote_data);
RegsArm64* regs = new RegsArm64();
memcpy(regs->RawData(), &user->regs[0], (ARM64_REG_R31 + 1) * sizeof(uint64_t));
regs->set_pc(user->pc);
regs->set_sp(user->sp);
return regs;
}
static Regs* ReadX86(void* remote_data) {
x86_user_regs* user = reinterpret_cast<x86_user_regs*>(remote_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;
regs->set_pc(user->eip);
regs->set_sp(user->esp);
return regs;
}
static Regs* ReadX86_64(void* remote_data) {
x86_64_user_regs* user = reinterpret_cast<x86_64_user_regs*>(remote_data);
RegsX86_64* regs = new RegsX86_64();
(*regs)[X86_64_REG_RAX] = user->rax;
(*regs)[X86_64_REG_RBX] = user->rbx;
(*regs)[X86_64_REG_RCX] = user->rcx;
(*regs)[X86_64_REG_RDX] = user->rdx;
(*regs)[X86_64_REG_R8] = user->r8;
(*regs)[X86_64_REG_R9] = user->r9;
(*regs)[X86_64_REG_R10] = user->r10;
(*regs)[X86_64_REG_R11] = user->r11;
(*regs)[X86_64_REG_R12] = user->r12;
(*regs)[X86_64_REG_R13] = user->r13;
(*regs)[X86_64_REG_R14] = user->r14;
(*regs)[X86_64_REG_R15] = user->r15;
(*regs)[X86_64_REG_RDI] = user->rdi;
(*regs)[X86_64_REG_RSI] = user->rsi;
(*regs)[X86_64_REG_RBP] = user->rbp;
(*regs)[X86_64_REG_RSP] = user->rsp;
(*regs)[X86_64_REG_RIP] = user->rip;
regs->set_pc(user->rip);
regs->set_sp(user->rsp);
return regs;
}
// This function assumes that reg_data is already aligned to a 64 bit value.
// If not this could crash with an unaligned access.
Regs* Regs::RemoteGet(pid_t pid, uint32_t* machine_type) {
// Make the buffer large enough to contain the largest registers type.
std::vector<uint64_t> buffer(MAX_USER_REGS_SIZE / sizeof(uint64_t));
struct iovec io;
io.iov_base = buffer.data();
io.iov_len = buffer.size() * sizeof(uint64_t);
if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, reinterpret_cast<void*>(&io)) == -1) {
return nullptr;
}
switch (io.iov_len) {
case sizeof(x86_user_regs):
*machine_type = EM_386;
return ReadX86(buffer.data());
case sizeof(x86_64_user_regs):
*machine_type = EM_X86_64;
return ReadX86_64(buffer.data());
case sizeof(arm_user_regs):
*machine_type = EM_ARM;
return ReadArm(buffer.data());
case sizeof(arm64_user_regs):
*machine_type = EM_AARCH64;
return ReadArm64(buffer.data());
}
return nullptr;
}