text: //===-- AppleGetPendingItemsHandler.cpp -------------------------------*- C++
  //-*-===//
  //
  // 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 "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/ClangASTContext.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/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() {}
  
  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);
      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(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
  
    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) {
          Status error;
          m_get_pending_items_impl_code.reset(
              exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
                  g_get_pending_items_function_code, eLanguageTypeObjC,
                  g_get_pending_items_function_name, error));
          if (error.Fail()) {
            LLDB_LOGF(log,
                      "Failed to get UtilityFunction for pending-items "
                      "introspection: %s.",
                      error.AsCString());
            return args_addr;
          }
  
          if (!m_get_pending_items_impl_code->Install(diagnostics, exe_ctx)) {
            if (log) {
              LLDB_LOGF(log, "Failed to install pending-items introspection.");
              diagnostics.Dump(log);
            }
            m_get_pending_items_impl_code.reset();
            return args_addr;
          }
        } 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;
        ClangASTContext *clang_ast_context =
            ClangASTContext::GetScratch(thread.GetProcess()->GetTarget());
        CompilerType get_pending_items_return_type =
            clang_ast_context->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());
    ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
  
    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 =
        clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
    Value return_buffer_ptr_value;
    return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar);
    return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
  
    CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
    Value debug_value;
    debug_value.SetValueType(Value::eValueTypeScalar);
    debug_value.SetCompilerType(clang_int_type);
  
    CompilerType clang_uint64_type =
        clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
    Value queue_value;
    queue_value.SetValueType(Value::eValueTypeScalar);
    queue_value.SetCompilerType(clang_uint64_type);
  
    Value page_to_free_value;
    page_to_free_value.SetValueType(Value::eValueTypeScalar);
    page_to_free_value.SetCompilerType(clang_void_ptr_type);
  
    Value page_to_free_size_value;
    page_to_free_size_value.SetValueType(Value::eValueTypeScalar);
    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;
  }
  