llvm-project/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp

//===-- ProcessFreeBSDKernel.cpp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Target/DynamicLoader.h"

#include "Plugins/DynamicLoader/Static/DynamicLoaderStatic.h"
#include "ProcessFreeBSDKernel.h"
#include "ThreadFreeBSDKernel.h"

#if LLDB_ENABLE_FBSDVMCORE
#include <fvc.h>
#endif
#if defined(__FreeBSD__)
#include <kvm.h>
#endif

using namespace lldb;
using namespace lldb_private;

LLDB_PLUGIN_DEFINE(ProcessFreeBSDKernel)

namespace {

#if LLDB_ENABLE_FBSDVMCORE
class ProcessFreeBSDKernelFVC : public ProcessFreeBSDKernel {
public:
  ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp, lldb::ListenerSP listener,
                          fvc_t *fvc);

  ~ProcessFreeBSDKernelFVC();

  size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
                      lldb_private::Status &error) override;

private:
  fvc_t *m_fvc;

  const char *GetError();
};
#endif // LLDB_ENABLE_FBSDVMCORE

#if defined(__FreeBSD__)
class ProcessFreeBSDKernelKVM : public ProcessFreeBSDKernel {
public:
  ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp, lldb::ListenerSP listener,
                          kvm_t *fvc);

  ~ProcessFreeBSDKernelKVM();

  size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
                      lldb_private::Status &error) override;

private:
  kvm_t *m_kvm;

  const char *GetError();
};
#endif // defined(__FreeBSD__)

} // namespace

ProcessFreeBSDKernel::ProcessFreeBSDKernel(lldb::TargetSP target_sp,
                                           ListenerSP listener_sp)
    : PostMortemProcess(target_sp, listener_sp) {}

lldb::ProcessSP ProcessFreeBSDKernel::CreateInstance(lldb::TargetSP target_sp,
                                                     ListenerSP listener_sp,
                                                     const FileSpec *crash_file,
                                                     bool can_connect) {
  ModuleSP executable = target_sp->GetExecutableModule();
  if (crash_file && !can_connect && executable) {
#if LLDB_ENABLE_FBSDVMCORE
    fvc_t *fvc =
        fvc_open(executable->GetFileSpec().GetPath().c_str(),
                 crash_file->GetPath().c_str(), nullptr, nullptr, nullptr);
    if (fvc)
      return std::make_shared<ProcessFreeBSDKernelFVC>(target_sp, listener_sp,
                                                       fvc);
#endif

#if defined(__FreeBSD__)
    kvm_t *kvm =
        kvm_open2(executable->GetFileSpec().GetPath().c_str(),
                  crash_file->GetPath().c_str(), O_RDONLY, nullptr, nullptr);
    if (kvm)
      return std::make_shared<ProcessFreeBSDKernelKVM>(target_sp, listener_sp,
                                                       kvm);
#endif
  }
  return nullptr;
}

void ProcessFreeBSDKernel::Initialize() {
  static llvm::once_flag g_once_flag;

  llvm::call_once(g_once_flag, []() {
    PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                  GetPluginDescriptionStatic(), CreateInstance);
  });
}

void ProcessFreeBSDKernel::Terminate() {
  PluginManager::UnregisterPlugin(ProcessFreeBSDKernel::CreateInstance);
}

Status ProcessFreeBSDKernel::DoDestroy() { return Status(); }

bool ProcessFreeBSDKernel::CanDebug(lldb::TargetSP target_sp,
                                    bool plugin_specified_by_name) {
  return true;
}

void ProcessFreeBSDKernel::RefreshStateAfterStop() {}

bool ProcessFreeBSDKernel::DoUpdateThreadList(ThreadList &old_thread_list,
                                              ThreadList &new_thread_list) {
  if (old_thread_list.GetSize(false) == 0) {
    // Make up the thread the first time this is called so we can set our one
    // and only core thread state up.

    // We cannot construct a thread without a register context as that crashes
    // LLDB but we can construct a process without threads to provide minimal
    // memory reading support.
    switch (GetTarget().GetArchitecture().GetMachine()) {
    case llvm::Triple::aarch64:
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      break;
    default:
      return false;
    }

    const Symbol *pcb_sym =
        GetTarget().GetExecutableModule()->FindFirstSymbolWithNameAndType(
            ConstString("dumppcb"));
    ThreadSP thread_sp(new ThreadFreeBSDKernel(
        *this, 1, pcb_sym ? pcb_sym->GetFileAddress() : LLDB_INVALID_ADDRESS));
    new_thread_list.AddThread(thread_sp);
  } else {
    const uint32_t num_threads = old_thread_list.GetSize(false);
    for (uint32_t i = 0; i < num_threads; ++i)
      new_thread_list.AddThread(old_thread_list.GetThreadAtIndex(i, false));
  }
  return new_thread_list.GetSize(false) > 0;
}

Status ProcessFreeBSDKernel::DoLoadCore() {
  // The core is already loaded by CreateInstance().
  return Status();
}

DynamicLoader *ProcessFreeBSDKernel::GetDynamicLoader() {
  if (m_dyld_up.get() == nullptr)
    m_dyld_up.reset(DynamicLoader::FindPlugin(
        this, DynamicLoaderStatic::GetPluginNameStatic()));
  return m_dyld_up.get();
}

#if LLDB_ENABLE_FBSDVMCORE

ProcessFreeBSDKernelFVC::ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp,
                                                 ListenerSP listener_sp,
                                                 fvc_t *fvc)
    : ProcessFreeBSDKernel(target_sp, listener_sp), m_fvc(fvc) {}

ProcessFreeBSDKernelFVC::~ProcessFreeBSDKernelFVC() {
  if (m_fvc)
    fvc_close(m_fvc);
}

size_t ProcessFreeBSDKernelFVC::DoReadMemory(lldb::addr_t addr, void *buf,
                                             size_t size, Status &error) {
  ssize_t rd = 0;
  rd = fvc_read(m_fvc, addr, buf, size);
  if (rd < 0 || static_cast<size_t>(rd) != size) {
    error.SetErrorStringWithFormat("Reading memory failed: %s", GetError());
    return rd > 0 ? rd : 0;
  }
  return rd;
}

const char *ProcessFreeBSDKernelFVC::GetError() { return fvc_geterr(m_fvc); }

#endif // LLDB_ENABLE_FBSDVMCORE

#if defined(__FreeBSD__)

ProcessFreeBSDKernelKVM::ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp,
                                                 ListenerSP listener_sp,
                                                 kvm_t *fvc)
    : ProcessFreeBSDKernel(target_sp, listener_sp), m_kvm(fvc) {}

ProcessFreeBSDKernelKVM::~ProcessFreeBSDKernelKVM() {
  if (m_kvm)
    kvm_close(m_kvm);
}

size_t ProcessFreeBSDKernelKVM::DoReadMemory(lldb::addr_t addr, void *buf,
                                             size_t size, Status &error) {
  ssize_t rd = 0;
  rd = kvm_read2(m_kvm, addr, buf, size);
  if (rd < 0 || static_cast<size_t>(rd) != size) {
    error.SetErrorStringWithFormat("Reading memory failed: %s", GetError());
    return rd > 0 ? rd : 0;
  }
  return rd;
}

const char *ProcessFreeBSDKernelKVM::GetError() { return kvm_geterr(m_kvm); }

#endif // defined(__FreeBSD__)