Sean Callanan bb9945f447 Made IRMemoryMap::FindSpace a little cleverer,
and made attempts to allocate memory in the process
fall back to FindSpace and just allocate memory on
the host (but with real-looking pointers, hence
FindSpace) if the process doesn't allow allocation.
This allows expressions to run on processes that don't
support allocation, like core files.

This introduces an extremely rare potential problem:
If all of the following are true:

- The Process doesn't support allocation;

- the user writes an expression that refers to an
  address that does not yet map to anything, or is
  dynamically generated (e.g., the result of calling
  a function); and

- the randomly-selected address for the static data
  for that specific expression runs into the
  address the user was expecting to work with;

then dereferencing the pointer later results
in the user seeing something unexpected.  This is
unlikely but possible; as a future piece of work,
we should have processes be able to hint to the
expression parser where it can allocate temporary data
of this kind.

llvm-svn: 179827
2013-04-19 01:51:24 +00:00

706 lines
21 KiB
C++

//===-- IRMemoryMap.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/Core/DataBufferHeap.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Expression/IRMemoryMap.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
using namespace lldb_private;
IRMemoryMap::IRMemoryMap (lldb::TargetSP target_sp) :
m_target_wp(target_sp)
{
if (target_sp)
m_process_wp = target_sp->GetProcessSP();
}
IRMemoryMap::~IRMemoryMap ()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
for (AllocationMap::value_type &allocation : m_allocations)
{
if (allocation.second.m_policy == eAllocationPolicyMirror ||
allocation.second.m_policy == eAllocationPolicyHostOnly)
process_sp->DeallocateMemory(allocation.second.m_process_alloc);
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::~IRMemoryMap deallocated [0x%llx..0x%llx)",
(uint64_t)allocation.second.m_process_start,
(uint64_t)allocation.second.m_process_start + (uint64_t)allocation.second.m_size);
}
}
}
}
lldb::addr_t
IRMemoryMap::FindSpace (size_t size)
{
lldb::TargetSP target_sp = m_target_wp.lock();
lldb::ProcessSP process_sp = m_process_wp.lock();
lldb::addr_t ret = LLDB_INVALID_ADDRESS;
for (int iterations = 0; iterations < 16; ++iterations)
{
lldb::addr_t candidate;
switch (target_sp->GetArchitecture().GetAddressByteSize())
{
case 4:
{
uint32_t random_data = random();
candidate = random_data;
candidate &= ~0xfffull;
break;
}
case 8:
{
uint32_t random_low = random();
uint32_t random_high = random();
candidate = random_high;
candidate <<= 32ull;
candidate |= random_low;
candidate &= ~0xfffull;
break;
}
}
if (IntersectsAllocation(candidate, size))
continue;
char buf[1];
Error err;
if (process_sp &&
(process_sp->ReadMemory(candidate, buf, 1, err) == 1 ||
process_sp->ReadMemory(candidate + size, buf, 1, err) == 1))
continue;
ret = candidate;
}
return ret;
}
IRMemoryMap::AllocationMap::iterator
IRMemoryMap::FindAllocation (lldb::addr_t addr, size_t size)
{
if (addr == LLDB_INVALID_ADDRESS)
return m_allocations.end();
AllocationMap::iterator iter = m_allocations.lower_bound (addr);
if (iter == m_allocations.end() ||
iter->first > addr)
{
if (iter == m_allocations.begin())
return m_allocations.end();
iter--;
}
if (iter->first <= addr && iter->first + iter->second.m_size >= addr + size)
return iter;
return m_allocations.end();
}
bool
IRMemoryMap::IntersectsAllocation (lldb::addr_t addr, size_t size)
{
if (addr == LLDB_INVALID_ADDRESS)
return false;
AllocationMap::iterator iter = m_allocations.lower_bound (addr);
if (iter == m_allocations.end() ||
iter->first > addr)
{
if (iter == m_allocations.begin())
return false;
iter--;
}
while (iter != m_allocations.end() && iter->second.m_process_alloc < addr + size)
{
if (iter->second.m_process_start + iter->second.m_size > addr)
return true;
++iter;
}
return false;
}
lldb::ByteOrder
IRMemoryMap::GetByteOrder()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp->GetByteOrder();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp->GetArchitecture().GetByteOrder();
return lldb::eByteOrderInvalid;
}
uint32_t
IRMemoryMap::GetAddressByteSize()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp->GetAddressByteSize();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp->GetArchitecture().GetAddressByteSize();
return UINT32_MAX;
}
ExecutionContextScope *
IRMemoryMap::GetBestExecutionContextScope()
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
return process_sp.get();
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
return target_sp.get();
return NULL;
}
lldb::addr_t
IRMemoryMap::Malloc (size_t size, uint8_t alignment, uint32_t permissions, AllocationPolicy policy, Error &error)
{
error.Clear();
lldb::ProcessSP process_sp;
lldb::addr_t allocation_address = LLDB_INVALID_ADDRESS;
lldb::addr_t aligned_address = LLDB_INVALID_ADDRESS;
size_t allocation_size = (size ? size : 1) + alignment - 1;
switch (policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: invalid allocation policy");
return LLDB_INVALID_ADDRESS;
case eAllocationPolicyHostOnly:
allocation_address = FindSpace(allocation_size);
if (allocation_address == LLDB_INVALID_ADDRESS)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: address space is full");
return LLDB_INVALID_ADDRESS;
}
break;
case eAllocationPolicyMirror:
process_sp = m_process_wp.lock();
if (process_sp && process_sp->CanJIT())
{
allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
if (!error.Success())
return LLDB_INVALID_ADDRESS;
}
else
{
policy = eAllocationPolicyHostOnly;
allocation_address = FindSpace(allocation_size);
if (allocation_address == LLDB_INVALID_ADDRESS)
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: address space is full");
return LLDB_INVALID_ADDRESS;
}
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
if (process_sp->CanJIT())
{
allocation_address = process_sp->AllocateMemory(allocation_size, permissions, error);
if (!error.Success())
return LLDB_INVALID_ADDRESS;
}
else
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: process doesn't support allocating memory");
return LLDB_INVALID_ADDRESS;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't malloc: process doesn't exist, and this memory must be in the process");
return LLDB_INVALID_ADDRESS;
}
break;
}
lldb::addr_t mask = alignment - 1;
aligned_address = (allocation_address + mask) & (~mask);
Allocation allocation;
allocation.m_process_alloc = allocation_address;
allocation.m_process_start = aligned_address;
allocation.m_size = size;
allocation.m_permissions = permissions;
allocation.m_alignment = alignment;
allocation.m_policy = policy;
m_allocations[aligned_address] = std::move(allocation);
switch (policy)
{
default:
assert (0 && "We cannot reach this!");
case eAllocationPolicyHostOnly:
allocation.m_data_ap.reset(new DataBufferHeap(size, 0));
break;
case eAllocationPolicyProcessOnly:
break;
case eAllocationPolicyMirror:
allocation.m_data_ap.reset(new DataBufferHeap(size, 0));
break;
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
const char * policy_string;
switch (policy)
{
default:
policy_string = "<invalid policy>";
break;
case eAllocationPolicyHostOnly:
policy_string = "eAllocationPolicyHostOnly";
break;
case eAllocationPolicyProcessOnly:
policy_string = "eAllocationPolicyProcessOnly";
break;
case eAllocationPolicyMirror:
policy_string = "eAllocationPolicyMirror";
break;
}
log->Printf("IRMemoryMap::Malloc (%llu, 0x%llx, 0x%llx, %s) -> 0x%llx",
(uint64_t)size,
(uint64_t)alignment,
(uint64_t)permissions,
policy_string,
aligned_address);
}
return aligned_address;
}
void
IRMemoryMap::Free (lldb::addr_t process_address, Error &error)
{
error.Clear();
AllocationMap::iterator iter = m_allocations.find(process_address);
if (iter == m_allocations.end())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't free: allocation doesn't exist");
return;
}
Allocation &allocation = iter->second;
switch (allocation.m_policy)
{
default:
case eAllocationPolicyHostOnly:
break;
case eAllocationPolicyMirror:
case eAllocationPolicyProcessOnly:
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
process_sp->DeallocateMemory(allocation.m_process_alloc);
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::Free (0x%llx) freed [0x%llx..0x%llx)",
(uint64_t)process_address,
iter->second.m_process_start,
iter->second.m_process_start + iter->second.m_size);
}
m_allocations.erase(iter);
}
void
IRMemoryMap::WriteMemory (lldb::addr_t process_address, const uint8_t *bytes, size_t size, Error &error)
{
error.Clear();
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
return;
}
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: no allocation contains the target range and the process doesn't exist");
return;
}
Allocation &allocation = iter->second;
uint64_t offset = process_address - allocation.m_process_start;
lldb::ProcessSP process_sp;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: invalid allocation policy");
return;
case eAllocationPolicyHostOnly:
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: data buffer is empty");
return;
}
::memcpy (allocation.m_data_ap->GetBytes() + offset, bytes, size);
break;
case eAllocationPolicyMirror:
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't write: data buffer is empty");
return;
}
::memcpy (allocation.m_data_ap->GetBytes() + offset, bytes, size);
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->WriteMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::WriteMemory (0x%llx, 0x%llx, 0x%lld) went to [0x%llx..0x%llx)",
(uint64_t)process_address,
(uint64_t)bytes,
(uint64_t)size,
(uint64_t)allocation.m_process_start,
(uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
}
}
void
IRMemoryMap::WriteScalarToMemory (lldb::addr_t process_address, Scalar &scalar, size_t size, Error &error)
{
error.Clear();
if (size == UINT32_MAX)
size = scalar.GetByteSize();
if (size > 0)
{
uint8_t buf[32];
const size_t mem_size = scalar.GetAsMemoryData (buf, size, GetByteOrder(), error);
if (mem_size > 0)
{
return WriteMemory(process_address, buf, mem_size, error);
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't write scalar: failed to get scalar as memory data");
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't write scalar: its size was zero");
}
return;
}
void
IRMemoryMap::WritePointerToMemory (lldb::addr_t process_address, lldb::addr_t address, Error &error)
{
error.Clear();
Scalar scalar(address);
WriteScalarToMemory(process_address, scalar, GetAddressByteSize(), error);
}
void
IRMemoryMap::ReadMemory (uint8_t *bytes, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
return;
}
lldb::TargetSP target_sp = m_target_wp.lock();
if (target_sp)
{
Address absolute_address(process_address);
target_sp->ReadMemory(absolute_address, false, bytes, size, error);
return;
}
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: no allocation contains the target range, and neither the process nor the target exist");
return;
}
Allocation &allocation = iter->second;
uint64_t offset = process_address - allocation.m_process_start;
lldb::ProcessSP process_sp;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: invalid allocation policy");
return;
case eAllocationPolicyHostOnly:
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: data buffer is empty");
return;
}
::memcpy (bytes, allocation.m_data_ap->GetBytes() + offset, size);
break;
case eAllocationPolicyMirror:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
else
{
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't read: data buffer is empty");
return;
}
::memcpy (bytes, allocation.m_data_ap->GetBytes() + offset, size);
}
break;
case eAllocationPolicyProcessOnly:
process_sp = m_process_wp.lock();
if (process_sp)
{
process_sp->ReadMemory(process_address, bytes, size, error);
if (!error.Success())
return;
}
break;
}
if (lldb_private::Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS))
{
log->Printf("IRMemoryMap::ReadMemory (0x%llx, 0x%llx, 0x%lld) came from [0x%llx..0x%llx)",
(uint64_t)process_address,
(uint64_t)bytes,
(uint64_t)size,
(uint64_t)allocation.m_process_start,
(uint64_t)allocation.m_process_start + (uint64_t)allocation.m_size);
}
}
void
IRMemoryMap::ReadScalarFromMemory (Scalar &scalar, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
if (size > 0)
{
DataBufferHeap buf(size, 0);
ReadMemory(buf.GetBytes(), process_address, size, error);
if (!error.Success())
return;
DataExtractor extractor(buf.GetBytes(), buf.GetByteSize(), GetByteOrder(), GetAddressByteSize());
lldb::offset_t offset = 0;
switch (size)
{
default:
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Couldn't read scalar: unsupported size %lld", (unsigned long long)size);
return;
case 1: scalar = extractor.GetU8(&offset); break;
case 2: scalar = extractor.GetU16(&offset); break;
case 4: scalar = extractor.GetU32(&offset); break;
case 8: scalar = extractor.GetU64(&offset); break;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't read scalar: its size was zero");
}
return;
}
void
IRMemoryMap::ReadPointerFromMemory (lldb::addr_t *address, lldb::addr_t process_address, Error &error)
{
error.Clear();
Scalar pointer_scalar;
ReadScalarFromMemory(pointer_scalar, process_address, GetAddressByteSize(), error);
if (!error.Success())
return;
*address = pointer_scalar.ULongLong();
return;
}
void
IRMemoryMap::GetMemoryData (DataExtractor &extractor, lldb::addr_t process_address, size_t size, Error &error)
{
error.Clear();
if (size > 0)
{
AllocationMap::iterator iter = FindAllocation(process_address, size);
if (iter == m_allocations.end())
{
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Couldn't find an allocation containing [0x%llx..0x%llx)", (unsigned long long)process_address, (unsigned long long)(process_address + size));
return;
}
Allocation &allocation = iter->second;
switch (allocation.m_policy)
{
default:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: invalid allocation policy");
return;
case eAllocationPolicyProcessOnly:
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: memory is only in the target");
return;
case eAllocationPolicyMirror:
{
lldb::ProcessSP process_sp = m_process_wp.lock();
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: data buffer is empty");
return;
}
if (process_sp)
{
process_sp->ReadMemory(allocation.m_process_start, allocation.m_data_ap->GetBytes(), allocation.m_data_ap->GetByteSize(), error);
if (!error.Success())
return;
uint64_t offset = process_address - allocation.m_process_start;
extractor = DataExtractor(allocation.m_data_ap->GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
return;
}
}
case eAllocationPolicyHostOnly:
if (!allocation.m_data_ap.get())
{
error.SetErrorToGenericError();
error.SetErrorString("Couldn't get memory data: data buffer is empty");
return;
}
uint64_t offset = process_address - allocation.m_process_start;
extractor = DataExtractor(allocation.m_data_ap->GetBytes() + offset, size, GetByteOrder(), GetAddressByteSize());
return;
}
}
else
{
error.SetErrorToGenericError();
error.SetErrorString ("Couldn't get memory data: its size was zero");
return;
}
}