dumper.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

int
dumper::dump_module (asection * to, process_module * module)
{
  if (!sane ())
    return 0;

  if (to == NULL || module == NULL)
    return 0;

  struct win32_pstatus *module_pstatus_ptr;

  int note_length = sizeof (struct win32_pstatus) + strlen (module->name);

  char *buf = (char *) malloc (note_length);

  if (!buf)
    {
      fprintf (stderr, "Error alloating memory. Dumping aborted.\n");
      goto out;
    };

  module_pstatus_ptr = (struct win32_pstatus *) buf;

  note_header header;
  bfd_putl32 (NOTE_NAME_SIZE, header.elf_note_header.namesz);
  bfd_putl32 (note_length, header.elf_note_header.descsz);
  bfd_putl32 (NT_WIN32PSTATUS, header.elf_note_header.type);
  strncpy ((char *) &header.elf_note_header.name, "win32module", NOTE_NAME_SIZE);

  module_pstatus_ptr->data_type = NOTE_INFO_MODULE;
  module_pstatus_ptr->data.module_info.base_address = module->base_address;
  module_pstatus_ptr->data.module_info.module_name_size = strlen (module->name) + 1;
  strcpy (module_pstatus_ptr->data.module_info.module_name, module->name);

  if (!bfd_set_section_contents (core_bfd, to, &header,
				 0,
				 sizeof (header)) ||
      !bfd_set_section_contents (core_bfd, to, module_pstatus_ptr,
				 sizeof (header),
				 note_length))
    {
      bfd_perror ("writing module info to bfd");
      goto out;
    };
  return 1;

out:
  if (buf)
    free (buf);
  dumper_abort ();
  return 0;

}

int
dumper::collect_process_information ()
{
  int exception_level = 0;

  if (!sane ())
    return 0;

  if (!DebugActiveProcess (pid))
    {
      fprintf (stderr, "Cannot attach to process #%lu, error %ld", pid, GetLastError ());
      return 0;
    }

  char event_name[sizeof ("cygwin_error_start_event") + 20];
  sprintf (event_name, "cygwin_error_start_event%16lx", pid);
  HANDLE sync_with_debugee = OpenEvent (EVENT_MODIFY_STATE, FALSE, event_name);

  DEBUG_EVENT current_event;

  while (1)
    {
      if (!WaitForDebugEvent (&current_event, 20000))
	return 0;

      deb_printf ("got debug event %d\n", current_event.dwDebugEventCode);

      switch (current_event.dwDebugEventCode)
	{
	case CREATE_THREAD_DEBUG_EVENT:

	  if (!add_thread (current_event.dwThreadId,
			   current_event.u.CreateThread.hThread))
	    goto failed;

	  break;

	case CREATE_PROCESS_DEBUG_EVENT:

	  if (!add_module (current_event.u.CreateProcessInfo.lpBaseOfImage) ||
	      !add_thread (current_event.dwThreadId,
			   current_event.u.CreateProcessInfo.hThread))
	    goto failed;

	  break;

	case EXIT_PROCESS_DEBUG_EVENT:

	  deb_printf ("debugee quits");
	  ContinueDebugEvent (current_event.dwProcessId,
			      current_event.dwThreadId,
			      DBG_CONTINUE);

	  return 1;

	  break;

	case LOAD_DLL_DEBUG_EVENT:

	  if (!add_module (current_event.u.LoadDll.lpBaseOfDll))
	    goto failed;

	  break;

	case EXCEPTION_DEBUG_EVENT:

	  exception_level++;
	  if (exception_level == 2)
	    break;
	  else if (exception_level > 2)
	    return 0;

	  collect_memory_sections ();

	  /* got all info. time to dump */

	  if (!prepare_core_dump ())
	    {
	      fprintf (stderr, "Failed to prepare core dump\n");
	      goto failed;
	    };

	  if (!write_core_dump ())
	    {
	      fprintf (stderr, "Failed to write core dump\n");
	      goto failed;
	    };

	  /* signal a debugee that we've finished */
	  if (sync_with_debugee)
	    SetEvent (sync_with_debugee);

	  break;

	default:

	  break;

	}

      ContinueDebugEvent (current_event.dwProcessId,
			  current_event.dwThreadId,
			  DBG_CONTINUE);
    }
failed:
  /* set debugee free */
  if (sync_with_debugee)
    SetEvent (sync_with_debugee);

  return 0;
}

int
dumper::init_core_dump ()
{
  bfd_init ();

  core_bfd = bfd_openw (file_name, "elf32-i386");
  if (core_bfd == NULL)
    {
      bfd_perror ("opening bfd");
      goto failed;
    }

  if (!bfd_set_format (core_bfd, bfd_core))
    {
      bfd_perror ("setting bfd format");
      goto failed;
    }

  if (!bfd_set_arch_mach (core_bfd, bfd_arch_i386, 0))
    {
      bfd_perror ("setting bfd architecture");
      goto failed;
    }

  return 1;

failed:
  dumper_abort ();
  return 0;

}

int
dumper::prepare_core_dump ()
{
  if (!sane ())
    return 0;

  int sect_no = 0;
  char sect_name[50];

  flagword sect_flags;
  DWORD sect_size;
  bfd_vma sect_vma;

  asection *new_section;

  for (process_entity * p = list; p != NULL; p = p->next)
    {
      sect_no++;

      switch (p->type)
	{
	case pr_ent_memory:
	  sprintf (sect_name, ".mem/%u", sect_no);
	  sect_flags = SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD;
	  sect_size = p->u.memory.size;
	  sect_vma = (bfd_vma) (p->u.memory.base);

	  break;

	case pr_ent_thread:
	  sprintf (sect_name, ".note/%u", sect_no);
	  sect_flags = SEC_HAS_CONTENTS | SEC_LOAD;
	  sect_size = sizeof (note_header) + sizeof (struct win32_pstatus);
	  sect_vma = 0;
	  break;

	case pr_ent_module:
	  sprintf (sect_name, ".note/%u", sect_no);
	  sect_flags = SEC_HAS_CONTENTS | SEC_LOAD;
	  sect_size = sizeof (note_header) + sizeof (struct win32_pstatus) +
	    (bfd_size_type) (strlen (p->u.module.name));
	  sect_vma = 0;
	  break;

	default:
	  continue;
	}

      if (p->type == pr_ent_module && status_section != NULL)
	{
	  if (!bfd_set_section_size (core_bfd,
				     status_section,
				     status_section->_raw_size + sect_size))
	    {
	      bfd_perror ("resizing status section");
	      goto failed;
	    };
	  continue;
	}

      deb_printf ("creating section (type%u) %s(%u), flags=%08x\n",
		  p->type, sect_name, sect_size, sect_flags);

      bfd_set_error (bfd_error_no_error);
      char *buf = strdup (sect_name);
      new_section = bfd_make_section (core_bfd, buf);
      if (new_section == NULL)
	{
	  if (bfd_get_error () == bfd_error_no_error)
	    fprintf (stderr, "error creating new section (%s), section already exists.\n", buf);
	  else
	    bfd_perror ("creating section");
	  goto failed;
	}

      if (!bfd_set_section_flags (core_bfd, new_section, sect_flags) ||
	  !bfd_set_section_size (core_bfd, new_section, sect_size))
	{
	  bfd_perror ("setting section attributes");
	  goto failed;
	};

      new_section->vma = sect_vma;
      new_section->output_section = new_section;
      new_section->output_offset = 0;
      p->section = new_section;
    }

  return 1;

failed:
  dumper_abort ();
  return 0;
}

int
dumper::write_core_dump ()
{
  if (!sane ())
    return 0;

  for (process_entity * p = list; p != NULL; p = p->next)
    {
      if (p->section == NULL)
	continue;

      deb_printf ("writing section type=%u base=%08x size=%08x flags=%08x\n",
		  p->type,
		  p->section->vma,
		  p->section->_raw_size,
		  p->section->flags);

      switch (p->type)
	{
	case pr_ent_memory:
	  dump_memory_region (p->section, &(p->u.memory));
	  break;

	case pr_ent_thread:
	  dump_thread (p->section, &(p->u.thread));
	  break;

	case pr_ent_module:
	  dump_module (p->section, &(p->u.module));
	  break;

	default:
	  continue;

	}
    }
  return 1;
}

static void
usage (FILE *stream, int status)
{
  fprintf (stream, "\
Usage: dumper [OPTION] FILENAME WIN32PID\n\
Dump core from WIN32PID to FILENAME.core\n\
 -d, --verbose  be verbose while dumping\n\
 -h, --help     output help information and exit\n\
 -q, --quiet    be quiet while dumping (default)\n\
 -v, --version  output version information and exit\n\
");
  exit (status);
}

struct option longopts[] = {
  {"verbose", no_argument, NULL, 'd'},
  {"help", no_argument, NULL, 'h'},
  {"quiet", no_argument, NULL, 'q'},
  {"version", no_argument, 0, 'v'},
  {0, no_argument, NULL, 0}
};

static void 
print_version ()
{
  const char *v = strchr (version, ':');
  int len;
  if (!v)
    {
      v = "?";
      len = 1;
    }
  else
    {
      v += 2;
      len = strchr (v, ' ') - v;
    }
  printf ("\
dumper (cygwin) %.*s\n\
Core Dumper for Cygwin\n\
Copyright 1999, 2001, 2002 Red Hat, Inc.\n", len, v);
}

int
main (int argc, char **argv)
{
  int opt;
  const char *p = "";
  DWORD pid;
  char win32_name [MAX_PATH];

  while ((opt = getopt_long (argc, argv, "dqhv", longopts, NULL) ) != EOF)
    switch (opt)
      {
      case 'd':
	verbose = TRUE;
	break;
      case 'q':
	verbose = FALSE;
	break;
      case 'h':
	usage (stdout, 0);
      case 'v':
       print_version ();
       exit (0);
      default:
	usage (stderr, 1);
	break;
      }

  if (argv && *(argv + optind) && *(argv + optind +1))
    {
      *win32_name = '\0';
      cygwin_conv_to_win32_path (*(argv + optind), win32_name);
      if ((p = strrchr (win32_name, '\\')))
	p++;
      else
	p = win32_name;
      pid = strtoul (*(argv + optind + 1), NULL, 10);
    }
  else
    {
      usage (stderr, 1);
      return -1;
    }

  char *core_file = (char *) malloc (strlen (p) + sizeof (".core"));
  if (!core_file)
    {
      fprintf (stderr, "error allocating memory\n");
      return -1;
    }
  sprintf (core_file, "%s.core", p);

  DWORD tid = 0;

  if (verbose)
    printf ("dumping process #%lu to %s\n", pid, core_file);

  dumper d (pid, tid, core_file);
  if (!d.sane ())
    return -1;
  d.collect_process_information ();
  free (core_file);

  return 0;
};