Files
clang-p2996/lldb/source/Host/common/SoftwareBreakpoint.cpp
Zachary Turner bf9a77305f Move classes from Core -> Utility.
This moves the following classes from Core -> Utility.

ConstString
Error
RegularExpression
Stream
StreamString

The goal here is to get lldbUtility into a state where it has
no dependendencies except on itself and LLVM, so it can be the
starting point at which to start untangling LLDB's dependencies.
These are all low level and very widely used classes, and
previously lldbUtility had dependencies up to lldbCore in order
to use these classes.  So moving then down to lldbUtility makes
sense from both the short term and long term perspective in
solving this problem.

Differential Revision: https://reviews.llvm.org/D29427

llvm-svn: 293941
2017-02-02 21:39:50 +00:00

353 lines
14 KiB
C++

//===-- SoftwareBreakpoint.cpp ----------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Host/common/SoftwareBreakpoint.h"
#include "lldb/Core/Log.h"
#include "lldb/Host/Debug.h"
#include "lldb/Utility/Error.h"
#include "lldb/Host/common/NativeProcessProtocol.h"
using namespace lldb_private;
// -------------------------------------------------------------------
// static members
// -------------------------------------------------------------------
Error SoftwareBreakpoint::CreateSoftwareBreakpoint(
NativeProcessProtocol &process, lldb::addr_t addr, size_t size_hint,
NativeBreakpointSP &breakpoint_sp) {
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_BREAKPOINTS));
if (log)
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64, __FUNCTION__, addr);
// Validate the address.
if (addr == LLDB_INVALID_ADDRESS)
return Error("SoftwareBreakpoint::%s invalid load address specified.",
__FUNCTION__);
// Ask the NativeProcessProtocol subclass to fill in the correct software
// breakpoint
// trap for the breakpoint site.
size_t bp_opcode_size = 0;
const uint8_t *bp_opcode_bytes = NULL;
Error error = process.GetSoftwareBreakpointTrapOpcode(
size_hint, bp_opcode_size, bp_opcode_bytes);
if (error.Fail()) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to retrieve software "
"breakpoint trap opcode: %s",
__FUNCTION__, error.AsCString());
return error;
}
// Validate size of trap opcode.
if (bp_opcode_size == 0) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to retrieve any trap opcodes",
__FUNCTION__);
return Error("SoftwareBreakpoint::GetSoftwareBreakpointTrapOpcode() "
"returned zero, unable to get breakpoint trap for address "
"0x%" PRIx64,
addr);
}
if (bp_opcode_size > MAX_TRAP_OPCODE_SIZE) {
if (log)
log->Printf("SoftwareBreakpoint::%s cannot support %zu trapcode bytes, "
"max size is %zu",
__FUNCTION__, bp_opcode_size, MAX_TRAP_OPCODE_SIZE);
return Error("SoftwareBreakpoint::GetSoftwareBreakpointTrapOpcode() "
"returned too many trap opcode bytes: requires %zu but we "
"only support a max of %zu",
bp_opcode_size, MAX_TRAP_OPCODE_SIZE);
}
// Validate that we received opcodes.
if (!bp_opcode_bytes) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to retrieve trap opcode bytes",
__FUNCTION__);
return Error("SoftwareBreakpoint::GetSoftwareBreakpointTrapOpcode() "
"returned NULL trap opcode bytes, unable to get breakpoint "
"trap for address 0x%" PRIx64,
addr);
}
// Enable the breakpoint.
uint8_t saved_opcode_bytes[MAX_TRAP_OPCODE_SIZE];
error = EnableSoftwareBreakpoint(process, addr, bp_opcode_size,
bp_opcode_bytes, saved_opcode_bytes);
if (error.Fail()) {
if (log)
log->Printf("SoftwareBreakpoint::%s: failed to enable new breakpoint at "
"0x%" PRIx64 ": %s",
__FUNCTION__, addr, error.AsCString());
return error;
}
if (log)
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64 " -- SUCCESS",
__FUNCTION__, addr);
// Set the breakpoint and verified it was written properly. Now
// create a breakpoint remover that understands how to undo this
// breakpoint.
breakpoint_sp.reset(new SoftwareBreakpoint(process, addr, saved_opcode_bytes,
bp_opcode_bytes, bp_opcode_size));
return Error();
}
Error SoftwareBreakpoint::EnableSoftwareBreakpoint(
NativeProcessProtocol &process, lldb::addr_t addr, size_t bp_opcode_size,
const uint8_t *bp_opcode_bytes, uint8_t *saved_opcode_bytes) {
assert(bp_opcode_size <= MAX_TRAP_OPCODE_SIZE &&
"bp_opcode_size out of valid range");
assert(bp_opcode_bytes && "bp_opcode_bytes is NULL");
assert(saved_opcode_bytes && "saved_opcode_bytes is NULL");
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_BREAKPOINTS));
if (log)
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64, __FUNCTION__, addr);
// Save the original opcodes by reading them so we can restore later.
size_t bytes_read = 0;
Error error =
process.ReadMemory(addr, saved_opcode_bytes, bp_opcode_size, bytes_read);
if (error.Fail()) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to read memory while "
"attempting to set breakpoint: %s",
__FUNCTION__, error.AsCString());
return error;
}
// Ensure we read as many bytes as we expected.
if (bytes_read != bp_opcode_size) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to read memory while "
"attempting to set breakpoint: attempted to read %zu bytes "
"but only read %zu",
__FUNCTION__, bp_opcode_size, bytes_read);
return Error("SoftwareBreakpoint::%s failed to read memory while "
"attempting to set breakpoint: attempted to read %zu bytes "
"but only read %zu",
__FUNCTION__, bp_opcode_size, bytes_read);
}
// Log what we read.
if (log) {
int i = 0;
for (const uint8_t *read_byte = saved_opcode_bytes;
read_byte < saved_opcode_bytes + bp_opcode_size; ++read_byte) {
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64
" ovewriting byte index %d (was 0x%hhx)",
__FUNCTION__, addr, i++, *read_byte);
}
}
// Write a software breakpoint in place of the original opcode.
size_t bytes_written = 0;
error =
process.WriteMemory(addr, bp_opcode_bytes, bp_opcode_size, bytes_written);
if (error.Fail()) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to write memory while "
"attempting to set breakpoint: %s",
__FUNCTION__, error.AsCString());
return error;
}
// Ensure we wrote as many bytes as we expected.
if (bytes_written != bp_opcode_size) {
error.SetErrorStringWithFormat(
"SoftwareBreakpoint::%s failed write memory while attempting to set "
"breakpoint: attempted to write %zu bytes but only wrote %zu",
__FUNCTION__, bp_opcode_size, bytes_written);
if (log)
log->PutCString(error.AsCString());
return error;
}
uint8_t verify_bp_opcode_bytes[MAX_TRAP_OPCODE_SIZE];
size_t verify_bytes_read = 0;
error = process.ReadMemory(addr, verify_bp_opcode_bytes, bp_opcode_size,
verify_bytes_read);
if (error.Fail()) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to read memory while "
"attempting to verify the breakpoint set: %s",
__FUNCTION__, error.AsCString());
return error;
}
// Ensure we read as many verification bytes as we expected.
if (verify_bytes_read != bp_opcode_size) {
if (log)
log->Printf("SoftwareBreakpoint::%s failed to read memory while "
"attempting to verify breakpoint: attempted to read %zu "
"bytes but only read %zu",
__FUNCTION__, bp_opcode_size, verify_bytes_read);
return Error("SoftwareBreakpoint::%s failed to read memory while "
"attempting to verify breakpoint: attempted to read %zu bytes "
"but only read %zu",
__FUNCTION__, bp_opcode_size, verify_bytes_read);
}
if (::memcmp(bp_opcode_bytes, verify_bp_opcode_bytes, bp_opcode_size) != 0) {
if (log)
log->Printf("SoftwareBreakpoint::%s: verification of software breakpoint "
"writing failed - trap opcodes not successfully read back "
"after writing when setting breakpoint at 0x%" PRIx64,
__FUNCTION__, addr);
return Error("SoftwareBreakpoint::%s: verification of software breakpoint "
"writing failed - trap opcodes not successfully read back "
"after writing when setting breakpoint at 0x%" PRIx64,
__FUNCTION__, addr);
}
if (log)
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64 " -- SUCCESS",
__FUNCTION__, addr);
return Error();
}
// -------------------------------------------------------------------
// instance-level members
// -------------------------------------------------------------------
SoftwareBreakpoint::SoftwareBreakpoint(NativeProcessProtocol &process,
lldb::addr_t addr,
const uint8_t *saved_opcodes,
const uint8_t *trap_opcodes,
size_t opcode_size)
: NativeBreakpoint(addr), m_process(process), m_saved_opcodes(),
m_trap_opcodes(), m_opcode_size(opcode_size) {
assert(opcode_size > 0 && "setting software breakpoint with no trap opcodes");
assert(opcode_size <= MAX_TRAP_OPCODE_SIZE && "trap opcode size too large");
::memcpy(m_saved_opcodes, saved_opcodes, opcode_size);
::memcpy(m_trap_opcodes, trap_opcodes, opcode_size);
}
Error SoftwareBreakpoint::DoEnable() {
return EnableSoftwareBreakpoint(m_process, m_addr, m_opcode_size,
m_trap_opcodes, m_saved_opcodes);
}
Error SoftwareBreakpoint::DoDisable() {
Error error;
assert(m_addr && (m_addr != LLDB_INVALID_ADDRESS) &&
"can't remove a software breakpoint for an invalid address");
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_BREAKPOINTS));
if (log)
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64, __FUNCTION__,
m_addr);
assert((m_opcode_size > 0) &&
"cannot restore opcodes when there are no opcodes");
if (m_opcode_size > 0) {
// Clear a software breakpoint instruction
uint8_t curr_break_op[MAX_TRAP_OPCODE_SIZE];
bool break_op_found = false;
assert(m_opcode_size <= sizeof(curr_break_op));
// Read the breakpoint opcode
size_t bytes_read = 0;
error =
m_process.ReadMemory(m_addr, curr_break_op, m_opcode_size, bytes_read);
if (error.Success() && bytes_read < m_opcode_size) {
error.SetErrorStringWithFormat(
"SoftwareBreakpointr::%s addr=0x%" PRIx64
": tried to read %zu bytes but only read %zu",
__FUNCTION__, m_addr, m_opcode_size, bytes_read);
}
if (error.Success()) {
bool verify = false;
// Make sure the breakpoint opcode exists at this address
if (::memcmp(curr_break_op, m_trap_opcodes, m_opcode_size) == 0) {
break_op_found = true;
// We found a valid breakpoint opcode at this address, now restore
// the saved opcode.
size_t bytes_written = 0;
error = m_process.WriteMemory(m_addr, m_saved_opcodes, m_opcode_size,
bytes_written);
if (error.Success() && bytes_written < m_opcode_size) {
error.SetErrorStringWithFormat(
"SoftwareBreakpoint::%s addr=0x%" PRIx64
": tried to write %zu bytes but only wrote %zu",
__FUNCTION__, m_addr, m_opcode_size, bytes_written);
}
if (error.Success()) {
verify = true;
}
} else {
error.SetErrorString(
"Original breakpoint trap is no longer in memory.");
// Set verify to true and so we can check if the original opcode has
// already been restored
verify = true;
}
if (verify) {
uint8_t verify_opcode[MAX_TRAP_OPCODE_SIZE];
assert(m_opcode_size <= sizeof(verify_opcode));
// Verify that our original opcode made it back to the inferior
size_t verify_bytes_read = 0;
error = m_process.ReadMemory(m_addr, verify_opcode, m_opcode_size,
verify_bytes_read);
if (error.Success() && verify_bytes_read < m_opcode_size) {
error.SetErrorStringWithFormat(
"SoftwareBreakpoint::%s addr=0x%" PRIx64
": tried to read %zu verification bytes but only read %zu",
__FUNCTION__, m_addr, m_opcode_size, verify_bytes_read);
}
if (error.Success()) {
// compare the memory we just read with the original opcode
if (::memcmp(m_saved_opcodes, verify_opcode, m_opcode_size) == 0) {
// SUCCESS
if (log) {
int i = 0;
for (const uint8_t *verify_byte = verify_opcode;
verify_byte < verify_opcode + m_opcode_size; ++verify_byte) {
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64
" replaced byte index %d with 0x%hhx",
__FUNCTION__, m_addr, i++, *verify_byte);
}
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64
" -- SUCCESS",
__FUNCTION__, m_addr);
}
return error;
} else {
if (break_op_found)
error.SetErrorString("Failed to restore original opcode.");
}
} else
error.SetErrorString("Failed to read memory to verify that "
"breakpoint trap was restored.");
}
}
}
if (log && error.Fail())
log->Printf("SoftwareBreakpoint::%s addr = 0x%" PRIx64 " -- FAILED: %s",
__FUNCTION__, m_addr, error.AsCString());
return error;
}
bool SoftwareBreakpoint::IsSoftwareBreakpoint() const { return true; }