| //===-- 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 "SoftwareBreakpoint.h" |
| |
| #include "lldb/Core/Error.h" |
| #include "lldb/Core/Log.h" |
| #include "lldb/Host/Debug.h" |
| #include "lldb/Host/Mutex.h" |
| |
| #include "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 %lu trapcode bytes, max size is %lu", __FUNCTION__, bp_opcode_size, MAX_TRAP_OPCODE_SIZE); |
| return Error ("SoftwareBreakpoint::GetSoftwareBreakpointTrapOpcode() returned too many trap opcode bytes: requires %lu but we only support a max of %lu", 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. |
| lldb::addr_t bytes_read = 0; |
| |
| Error error = process.ReadMemory(addr, saved_opcode_bytes, static_cast<lldb::addr_t> (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 != static_cast<lldb::addr_t> (bp_opcode_size)) |
| { |
| if (log) |
| log->Printf ("SoftwareBreakpoint::%s failed to read memory while attempting to set breakpoint: attempted to read %lu bytes but only read %" PRIu64, __FUNCTION__, bp_opcode_size, bytes_read); |
| return Error ("SoftwareBreakpoint::%s failed to read memory while attempting to set breakpoint: attempted to read %lu bytes but only read %" PRIu64, __FUNCTION__, bp_opcode_size, bytes_read); |
| } |
| |
| // Write a software breakpoint in place of the original opcode. |
| lldb::addr_t bytes_written = 0; |
| error = process.WriteMemory (addr, bp_opcode_bytes, static_cast<lldb::addr_t> (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 != static_cast<lldb::addr_t> (bp_opcode_size)) |
| { |
| error.SetErrorStringWithFormat("SoftwareBreakpoint::%s failed write memory while attempting to set breakpoint: attempted to write %lu bytes but only wrote %" PRIu64, __FUNCTION__, bp_opcode_size, bytes_written); |
| if (log) |
| log->PutCString (error.AsCString ()); |
| return error; |
| } |
| |
| uint8_t verify_bp_opcode_bytes [MAX_TRAP_OPCODE_SIZE]; |
| lldb::addr_t verify_bytes_read = 0; |
| error = process.ReadMemory(addr, verify_bp_opcode_bytes, static_cast<lldb::addr_t> (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 != static_cast<lldb::addr_t> (bp_opcode_size)) |
| { |
| if (log) |
| log->Printf ("SoftwareBreakpoint::%s failed to read memory while attempting to verify breakpoint: attempted to read %lu bytes but only read %" PRIu64, __FUNCTION__, bp_opcode_size, verify_bytes_read); |
| return Error ("SoftwareBreakpoint::%s failed to read memory while attempting to verify breakpoint: attempted to read %lu bytes but only read %" PRIu64, __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 breakoint 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 |
| lldb::addr_t bytes_read = 0; |
| error = m_process.ReadMemory (m_addr, curr_break_op, m_opcode_size, bytes_read); |
| if (error.Success () && (bytes_read < static_cast<lldb::addr_t> (m_opcode_size))) |
| { |
| error.SetErrorStringWithFormat ("SoftwareBreakpointr::%s addr=0x%" PRIx64 ": tried to read %lu bytes but only read %" PRIu64, __FUNCTION__, m_addr, m_opcode_size, bytes_read); |
| } |
| if (error.Success ()) |
| { |
| bool verify = false; |
| // Make sure we have the a 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. |
| lldb::addr_t bytes_written = 0; |
| error = m_process.WriteMemory (m_addr, m_saved_opcodes, m_opcode_size, bytes_written); |
| if (error.Success () && (bytes_written < static_cast<lldb::addr_t> (m_opcode_size))) |
| { |
| error.SetErrorStringWithFormat ("SoftwareBreakpoint::%s addr=0x%" PRIx64 ": tried to write %lu bytes but only wrote %" PRIu64, __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 |
| |
| lldb::addr_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 < static_cast<lldb::addr_t> (m_opcode_size))) |
| { |
| error.SetErrorStringWithFormat ("SoftwareBreakpoint::%s addr=0x%" PRIx64 ": tried to read %lu verification bytes but only read %" PRIu64, __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) |
| 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; |
| } |
| |
