/**

 * WinPR: Windows Portable Runtime

 * WinPR Debugging helpers

 *

 * Copyright 2022 Armin Novak <armin.novak@thincast.com>

 * Copyright 2022 Thincast Technologies GmbH

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef _GNU_SOURCE

#define _GNU_SOURCE // NOLINT(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)

#endif

#include <assert.h>

#include <stdlib.h>

#include <unwind.h>

#include <winpr/string.h>

#include "debug.h"

#include <winpr/wlog.h>

#include "../log.h"

#include <dlfcn.h>

#define TAG WINPR_TAG("utils.unwind")

#define UNWIND_MAX_LINE_SIZE 1024ULL

typedef struct

{

  union

  {

    uintptr_t uw;

    void* pv;

  } pc;

  union

  {

    uintptr_t uptr;

    void* pv;

  } langSpecificData;

} unwind_info_t;

typedef struct

{

  size_t pos;

  size_t size;

  unwind_info_t* info;

} unwind_context_t;

static const char* unwind_reason_str(_Unwind_Reason_Code code)

{

  switch (code)

  {

#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \

    !defined(__SEH__)

    case _URC_OK:

      return "_URC_OK";

#else

    case _URC_NO_REASON:

      return "_URC_NO_REASON";

    case _URC_FATAL_PHASE2_ERROR:

      return "_URC_FATAL_PHASE2_ERROR";

    case _URC_FATAL_PHASE1_ERROR:

      return "_URC_FATAL_PHASE1_ERROR";

    case _URC_NORMAL_STOP:

      return "_URC_NORMAL_STOP";

#endif

    case _URC_FOREIGN_EXCEPTION_CAUGHT:

      return "_URC_FOREIGN_EXCEPTION_CAUGHT";

    case _URC_END_OF_STACK:

      return "_URC_END_OF_STACK";

    case _URC_HANDLER_FOUND:

      return "_URC_HANDLER_FOUND";

    case _URC_INSTALL_CONTEXT:

      return "_URC_INSTALL_CONTEXT";

    case _URC_CONTINUE_UNWIND:

      return "_URC_CONTINUE_UNWIND";

#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \

    !defined(__SEH__)

    case _URC_FAILURE:

      return "_URC_FAILURE";

#endif

    default:

      return "_URC_UNKNOWN";

  }

}

static const char* unwind_reason_str_buffer(_Unwind_Reason_Code code, char* buffer, size_t size)

{

  const char* str = unwind_reason_str(code);

  (void)_snprintf(buffer, size, "%s [0x%02x]", str, code);

  return buffer;

}

static _Unwind_Reason_Code unwind_backtrace_callback(struct _Unwind_Context* context, void* arg)

{

  unwind_context_t* ctx = arg;

  assert(ctx);

  if (ctx->pos < ctx->size)

  {

    unwind_info_t* info = &ctx->info[ctx->pos++];

    info->pc.uw = _Unwind_GetIP(context);

    /* _Unwind_GetLanguageSpecificData has various return value definitions,

     * cast to the type we expect and disable linter warnings

     */

    // NOLINTNEXTLINE(google-readability-casting,readability-redundant-casting)

    info->langSpecificData.pv = (void*)_Unwind_GetLanguageSpecificData(context);

  }

  return _URC_NO_REASON;

}

void* winpr_unwind_backtrace(DWORD size)

{

  _Unwind_Reason_Code rc = _URC_FOREIGN_EXCEPTION_CAUGHT;

  unwind_context_t* ctx = calloc(1, sizeof(unwind_context_t));

  if (!ctx)

    goto fail;

  ctx->size = size;

  ctx->info = calloc(size, sizeof(unwind_info_t));

  if (!ctx->info)

    goto fail;

  rc = _Unwind_Backtrace(unwind_backtrace_callback, ctx);

  if (rc != _URC_END_OF_STACK)

  {

    /* https://github.com/FreeRDP/FreeRDP/issues/11490

     *

     * there seems to be no consensus on what to return from this function.

     * so we just warn about unexpected return codes and return the context regardless.

     */

    char buffer[64] = { 0 };

    WLog_WARN(TAG, "_Unwind_Backtrace failed with %s",

              unwind_reason_str_buffer(rc, buffer, sizeof(buffer)));

  }

  return ctx;

fail:

  winpr_unwind_backtrace_free(ctx);

  return NULL;

}

void winpr_unwind_backtrace_free(void* buffer)

{

  unwind_context_t* ctx = buffer;

  if (!ctx)

    return;

  free(ctx->info);

  free(ctx);

}

char** winpr_unwind_backtrace_symbols(void* buffer, size_t* used)

{

  union

  {

    void* pv;

    char* cp;

    char** cpp;

  } cnv;

  unwind_context_t* ctx = buffer;

  cnv.cpp = NULL;

  if (!ctx)

    return NULL;

  cnv.pv = calloc(ctx->pos * (sizeof(char*) + UNWIND_MAX_LINE_SIZE), sizeof(char*));

  if (!cnv.pv)

    return NULL;

  if (used)

    *used = ctx->pos;

  for (size_t x = 0; x < ctx->pos; x++)

  {

    char* msg = cnv.cp + ctx->pos * sizeof(char*) + x * UNWIND_MAX_LINE_SIZE;

    const unwind_info_t* info = &ctx->info[x];

    Dl_info dlinfo = { 0 };

    int rc = dladdr(info->pc.pv, &dlinfo);

    cnv.cpp[x] = msg;

    if (rc == 0)

      (void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "unresolvable, address=%p", info->pc.pv);

    else

      (void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "dli_fname=%s [%p], dli_sname=%s [%p]",

                      dlinfo.dli_fname, dlinfo.dli_fbase, dlinfo.dli_sname, dlinfo.dli_saddr);

  }

  // NOLINTNEXTLINE(clang-analyzer-unix.Malloc): function is an allocator

  return cnv.cpp;

}