//===-- AppleGetPendingItemsHandler.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 "AppleGetPendingItemsHandler.h"

#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"

#include "lldb/Core/Module.h"

#include "lldb/Core/Value.h"

#include "lldb/Expression/DiagnosticManager.h"

#include "lldb/Expression/FunctionCaller.h"

#include "lldb/Expression/UtilityFunction.h"

#include "lldb/Symbol/Symbol.h"

#include "lldb/Target/ExecutionContext.h"

#include "lldb/Target/Process.h"

#include "lldb/Target/Target.h"

#include "lldb/Target/Thread.h"

#include "lldb/Utility/ConstString.h"

#include "lldb/Utility/LLDBLog.h"

#include "lldb/Utility/Log.h"

#include "lldb/Utility/StreamString.h"

using namespace lldb;

using namespace lldb_private;

const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name =

    "__lldb_backtrace_recording_get_pending_items";

const char *AppleGetPendingItemsHandler::g_get_pending_items_function_code =

    "                                  \n\

extern \"C\"                                                                                                    \n\

{                                                                                                               \n\

    /*                                                                                                          \n\

     * mach defines                                                                                             \n\

     */                                                                                                         \n\

                                                                                                                \n\

    typedef unsigned int uint32_t;                                                                              \n\

    typedef unsigned long long uint64_t;                                                                        \n\

    typedef uint32_t mach_port_t;                                                                               \n\

    typedef mach_port_t vm_map_t;                                                                               \n\

    typedef int kern_return_t;                                                                                  \n\

    typedef uint64_t mach_vm_address_t;                                                                         \n\

    typedef uint64_t mach_vm_size_t;                                                                            \n\

                                                                                                                \n\

    mach_port_t mach_task_self ();                                                                              \n\

    kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size);         \n\

                                                                                                                \n\

    /*                                                                                                          \n\

     * libBacktraceRecording defines                                                                            \n\

     */                                                                                                         \n\

                                                                                                                \n\

    typedef uint32_t queue_list_scope_t;                                                                        \n\

    typedef void *dispatch_queue_t;                                                                             \n\

    typedef void *introspection_dispatch_queue_info_t;                                                          \n\

    typedef void *introspection_dispatch_item_info_ref;                                                         \n\

                                                                                                                \n\

    extern uint64_t __introspection_dispatch_queue_get_pending_items (dispatch_queue_t queue,                   \n\

                                                 introspection_dispatch_item_info_ref *returned_queues_buffer,  \n\

                                                 uint64_t *returned_queues_buffer_size);                        \n\

    extern int printf(const char *format, ...);                                                                 \n\

                                                                                                                \n\

    /*                                                                                                          \n\

     * return type define                                                                                       \n\

     */                                                                                                         \n\

                                                                                                                \n\

    struct get_pending_items_return_values                                                                      \n\

    {                                                                                                           \n\

        uint64_t pending_items_buffer_ptr;    /* the address of the items buffer from libBacktraceRecording */  \n\

        uint64_t pending_items_buffer_size;   /* the size of the items buffer from libBacktraceRecording */     \n\

        uint64_t count;                /* the number of items included in the queues buffer */                  \n\

    };                                                                                                          \n\

                                                                                                                \n\

    void  __lldb_backtrace_recording_get_pending_items                                                          \n\

                                               (struct get_pending_items_return_values *return_buffer,          \n\

                                                int debug,                                                      \n\

                                                uint64_t /* dispatch_queue_t */ queue,                          \n\

                                                void *page_to_free,                                             \n\

                                                uint64_t page_to_free_size)                                     \n\

{                                                                                                               \n\

    if (debug)                                                                                                  \n\

      printf (\"entering get_pending_items with args return_buffer == %p, debug == %d, queue == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, queue, page_to_free, page_to_free_size); \n\

    if (page_to_free != 0)                                                                                      \n\

    {                                                                                                           \n\

        mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\

    }                                                                                                           \n\

                                                                                                                \n\

    return_buffer->count = __introspection_dispatch_queue_get_pending_items (                                   \n\

                                                      (void*) queue,                                            \n\

                                                      (void**)&return_buffer->pending_items_buffer_ptr,         \n\

                                                      &return_buffer->pending_items_buffer_size);               \n\

    if (debug)                                                                                                  \n\

        printf(\"result was count %lld\\n\", return_buffer->count);                                             \n\

}                                                                                                               \n\

}                                                                                                               \n\

";

AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process)

    : m_process(process), m_get_pending_items_impl_code(),

      m_get_pending_items_function_mutex(),

      m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS),

      m_get_pending_items_retbuffer_mutex() {}

AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() = default;

void AppleGetPendingItemsHandler::Detach() {

  if (m_process && m_process->IsAlive() &&

      m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) {

    std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex,

                                      std::defer_lock);

    (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer

    m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr);

  }

}

// Compile our __lldb_backtrace_recording_get_pending_items() function (from

// the source above in g_get_pending_items_function_code) if we don't find that

// function in the inferior already with USE_BUILTIN_FUNCTION defined.  (e.g.

// this would be the case for testing.)

//

// Insert the __lldb_backtrace_recording_get_pending_items into the inferior

// process if needed.

//

// Write the get_pending_items_arglist into the inferior's memory space to

// prepare for the call.

//

// Returns the address of the arguments written down in the inferior process,

// which can be used to make the function call.

lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction(

    Thread &thread, ValueList &get_pending_items_arglist) {

  ThreadSP thread_sp(thread.shared_from_this());

  ExecutionContext exe_ctx(thread_sp);

  DiagnosticManager diagnostics;

  Log *log = GetLog(LLDBLog::SystemRuntime);

  lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;

  FunctionCaller *get_pending_items_caller = nullptr;

  // Scope for mutex locker:

  {

    std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex);

    // First stage is to make the ClangUtility to hold our injected function:

    if (!m_get_pending_items_impl_code) {

      if (g_get_pending_items_function_code != nullptr) {

        auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(

            g_get_pending_items_function_code,

            g_get_pending_items_function_name, eLanguageTypeC, exe_ctx);

        if (!utility_fn_or_error) {

          LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),

                         "Failed to create UtilityFunction for pending-items "

                         "introspection: {0}.");

          return args_addr;

        }

        m_get_pending_items_impl_code = std::move(*utility_fn_or_error);

      } else {

        LLDB_LOGF(log, "No pending-items introspection code found.");

        return LLDB_INVALID_ADDRESS;

      }

      // Next make the runner function for our implementation utility function.

      Status error;

      TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(

          thread.GetProcess()->GetTarget());

      CompilerType get_pending_items_return_type =

          scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType();

      get_pending_items_caller =

          m_get_pending_items_impl_code->MakeFunctionCaller(

              get_pending_items_return_type, get_pending_items_arglist,

              thread_sp, error);

      if (error.Fail() || get_pending_items_caller == nullptr) {

        LLDB_LOGF(log,

                  "Failed to install pending-items introspection function "

                  "caller: %s.",

                  error.AsCString());

        m_get_pending_items_impl_code.reset();

        return args_addr;

      }

    }

  }

  diagnostics.Clear();

  if (get_pending_items_caller == nullptr) {

    LLDB_LOGF(log, "Failed to get get_pending_items_caller.");

    return LLDB_INVALID_ADDRESS;

  }

  // Now write down the argument values for this particular call.  This looks

  // like it might be a race condition if other threads were calling into here,

  // but actually it isn't because we allocate a new args structure for this

  // call by passing args_addr = LLDB_INVALID_ADDRESS...

  if (!get_pending_items_caller->WriteFunctionArguments(

          exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) {

    if (log) {

      LLDB_LOGF(log, "Error writing pending-items function arguments.");

      diagnostics.Dump(log);

    }

    return args_addr;

  }

  return args_addr;

}

AppleGetPendingItemsHandler::GetPendingItemsReturnInfo

AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue,

                                             addr_t page_to_free,

                                             uint64_t page_to_free_size,

                                             Status &error) {

  lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);

  ProcessSP process_sp(thread.CalculateProcess());

  TargetSP target_sp(thread.CalculateTarget());

  TypeSystemClangSP scratch_ts_sp =

      ScratchTypeSystemClang::GetForTarget(*target_sp);

  Log *log = GetLog(LLDBLog::SystemRuntime);

  GetPendingItemsReturnInfo return_value;

  return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;

  return_value.items_buffer_size = 0;

  return_value.count = 0;

  error.Clear();

  if (!thread.SafeToCallFunctions()) {

    LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,

              thread.GetID());

    error.SetErrorString("Not safe to call functions on this thread.");

    return return_value;

  }

  // Set up the arguments for a call to

  // struct get_pending_items_return_values

  // {

  //     uint64_t pending_items_buffer_ptr;    /* the address of the items

  //     buffer from libBacktraceRecording */

  //     uint64_t pending_items_buffer_size;   /* the size of the items buffer

  //     from libBacktraceRecording */

  //     uint64_t count;                /* the number of items included in the

  //     queues buffer */

  // };

  //

  // void  __lldb_backtrace_recording_get_pending_items

  //                                            (struct

  //                                            get_pending_items_return_values

  //                                            *return_buffer,

  //                                             int debug,

  //                                             uint64_t /* dispatch_queue_t */

  //                                             queue

  //                                             void *page_to_free,

  //                                             uint64_t page_to_free_size)

  // Where the return_buffer argument points to a 24 byte region of memory

  // already allocated by lldb in the inferior process.

  CompilerType clang_void_ptr_type =

      scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType();

  Value return_buffer_ptr_value;

  return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);

  return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);

  CompilerType clang_int_type = scratch_ts_sp->GetBasicType(eBasicTypeInt);

  Value debug_value;

  debug_value.SetValueType(Value::ValueType::Scalar);

  debug_value.SetCompilerType(clang_int_type);

  CompilerType clang_uint64_type =

      scratch_ts_sp->GetBasicType(eBasicTypeUnsignedLongLong);

  Value queue_value;

  queue_value.SetValueType(Value::ValueType::Scalar);

  queue_value.SetCompilerType(clang_uint64_type);

  Value page_to_free_value;

  page_to_free_value.SetValueType(Value::ValueType::Scalar);

  page_to_free_value.SetCompilerType(clang_void_ptr_type);

  Value page_to_free_size_value;

  page_to_free_size_value.SetValueType(Value::ValueType::Scalar);

  page_to_free_size_value.SetCompilerType(clang_uint64_type);

  std::lock_guard<std::mutex> guard(m_get_pending_items_retbuffer_mutex);

  if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) {

    addr_t bufaddr = process_sp->AllocateMemory(

        32, ePermissionsReadable | ePermissionsWritable, error);

    if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {

      LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "

                     "current queues func call");

      return return_value;

    }

    m_get_pending_items_return_buffer_addr = bufaddr;

  }

  ValueList argument_values;

  return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr;

  argument_values.PushValue(return_buffer_ptr_value);

  debug_value.GetScalar() = 0;

  argument_values.PushValue(debug_value);

  queue_value.GetScalar() = queue;

  argument_values.PushValue(queue_value);

  if (page_to_free != LLDB_INVALID_ADDRESS)

    page_to_free_value.GetScalar() = page_to_free;

  else

    page_to_free_value.GetScalar() = 0;

  argument_values.PushValue(page_to_free_value);

  page_to_free_size_value.GetScalar() = page_to_free_size;

  argument_values.PushValue(page_to_free_size_value);

  addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values);

  DiagnosticManager diagnostics;

  ExecutionContext exe_ctx;

  FunctionCaller *get_pending_items_caller =

      m_get_pending_items_impl_code->GetFunctionCaller();

  EvaluateExpressionOptions options;

  options.SetUnwindOnError(true);

  options.SetIgnoreBreakpoints(true);

  options.SetStopOthers(true);

#if __has_feature(address_sanitizer)

  options.SetTimeout(process_sp->GetUtilityExpressionTimeout());

#else

  options.SetTimeout(std::chrono::milliseconds(500));

#endif

  options.SetTryAllThreads(false);

  options.SetIsForUtilityExpr(true);

  thread.CalculateExecutionContext(exe_ctx);

  if (get_pending_items_caller == nullptr) {

    error.SetErrorString("Unable to compile function to call "

                         "__introspection_dispatch_queue_get_pending_items");

    return return_value;

  }

  ExpressionResults func_call_ret;

  Value results;

  func_call_ret = get_pending_items_caller->ExecuteFunction(

      exe_ctx, &args_addr, options, diagnostics, results);

  if (func_call_ret != eExpressionCompleted || !error.Success()) {

    LLDB_LOGF(log,

              "Unable to call "

              "__introspection_dispatch_queue_get_pending_items(), got "

              "ExpressionResults %d, error contains %s",

              func_call_ret, error.AsCString(""));

    error.SetErrorString("Unable to call "

                         "__introspection_dispatch_queue_get_pending_items() "

                         "for list of queues");

    return return_value;

  }

  return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(

      m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);

  if (!error.Success() ||

      return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) {

    return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;

    return return_value;

  }

  return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory(

      m_get_pending_items_return_buffer_addr + 8, 8, 0, error);

  if (!error.Success()) {

    return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;

    return return_value;

  }

  return_value.count = m_process->ReadUnsignedIntegerFromMemory(

      m_get_pending_items_return_buffer_addr + 16, 8, 0, error);

  if (!error.Success()) {

    return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;

    return return_value;

  }

  LLDB_LOGF(log,

            "AppleGetPendingItemsHandler called "

            "__introspection_dispatch_queue_get_pending_items "

            "(page_to_free == 0x%" PRIx64 ", size = %" PRId64

            "), returned page is at 0x%" PRIx64 ", size %" PRId64

            ", count = %" PRId64,

            page_to_free, page_to_free_size, return_value.items_buffer_ptr,

            return_value.items_buffer_size, return_value.count);

  return return_value;

}