unwind/debug.c

 
#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)
  {
    char buffer[64] = { 0 };
    WLog_ERR(TAG, "_Unwind_Backtrace failed with %s",
             unwind_reason_str_buffer(rc, buffer, sizeof(buffer)));
    goto fail;
  }
 
  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;
}