dtable.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

	     It seems like overkill, but... */
	  win32_name = strcpy (new_win32_name, unix_name);
	  for (p = (char *) win32_name; (p = strchr (p, '/')); p++)
	    *p = '\\';
	}
      fh->set_name (unix_name, win32_name, fh->get_unit ());
    }
  debug_printf ("fd %d, fh %p", fd, fh);
  return fd >= 0 ? (fds[fd] = fh) : fh;
}

fhandler_base *
dtable::dup_worker (fhandler_base *oldfh)
{
  fhandler_base *newfh = build_fhandler (-1, oldfh->get_device ());
  *newfh = *oldfh;
  newfh->set_io_handle (NULL);
  if (oldfh->dup (newfh))
    {
      cfree (newfh);
      newfh = NULL;
      return NULL;
    }

  newfh->set_close_on_exec_flag (0);
  MALLOC_CHECK;
  debug_printf ("duped '%s' old %p, new %p", oldfh->get_name (), oldfh->get_io_handle (), newfh->get_io_handle ());
  return newfh;
}

int
dtable::dup2 (int oldfd, int newfd)
{
  int res = -1;
  fhandler_base *newfh = NULL;	// = NULL to avoid an incorrect warning

  MALLOC_CHECK;
  debug_printf ("dup2 (%d, %d)", oldfd, newfd);
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "dup");

  if (not_open (oldfd))
    {
      syscall_printf ("fd %d not open", oldfd);
      set_errno (EBADF);
      goto done;
    }

  if (newfd < 0)
    {
      syscall_printf ("new fd out of bounds: %d", newfd);
      set_errno (EBADF);
      goto done;
    }

  if (newfd == oldfd)
    {
      res = 0;
      goto done;
    }

  if ((newfh = dup_worker (fds[oldfd])) == NULL)
    {
      res = -1;
      goto done;
    }

  debug_printf ("newfh->io_handle %p, oldfh->io_handle %p",
		newfh->get_io_handle (), fds[oldfd]->get_io_handle ());

  if (!not_open (newfd))
    close (newfd);
  else if ((size_t) newfd < size)
    /* nothing to do */;
  else if (find_unused_handle (newfd) < 0)
    {
      newfh->close ();
      res = -1;
      goto done;
    }

  fds[newfd] = newfh;

  if ((res = newfd) <= 2)
    set_std_handle (res);

done:
  MALLOC_CHECK;
  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "dup");
  syscall_printf ("%d = dup2 (%d, %d)", res, oldfd, newfd);

  return res;
}

select_record *
dtable::select_read (int fd, select_record *s)
{
  if (not_open (fd))
    {
      set_errno (EBADF);
      return NULL;
    }
  fhandler_base *fh = fds[fd];
  s = fh->select_read (s);
  s->fd = fd;
  s->fh = fh;
  s->saw_error = 0;
  debug_printf ("%s fd %d", fh->get_name (), fd);
  return s;
}

select_record *
dtable::select_write (int fd, select_record *s)
{
  if (not_open (fd))
    {
      set_errno (EBADF);
      return NULL;
    }
  fhandler_base *fh = fds[fd];
  s = fh->select_write (s);
  s->fd = fd;
  s->fh = fh;
  s->saw_error = 0;
  debug_printf ("%s fd %d", fh->get_name (), fd);
  return s;
}

select_record *
dtable::select_except (int fd, select_record *s)
{
  if (not_open (fd))
    {
      set_errno (EBADF);
      return NULL;
    }
  fhandler_base *fh = fds[fd];
  s = fh->select_except (s);
  s->fd = fd;
  s->fh = fh;
  s->saw_error = 0;
  debug_printf ("%s fd %d", fh->get_name (), fd);
  return s;
}

/* Function to walk the fd table after an exec and perform
   per-fhandler type fixups. */
void
dtable::fixup_before_fork (DWORD target_proc_id)
{
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "fixup_before_fork");
  fhandler_base *fh;
  for (size_t i = 0; i < size; i++)
    if ((fh = fds[i]) != NULL)
      {
	debug_printf ("fd %d (%s)", i, fh->get_name ());
	fh->fixup_before_fork_exec (target_proc_id);
      }
  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "fixup_before_fork");
}

void
dtable::fixup_before_exec (DWORD target_proc_id)
{
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "fixup_before_exec");
  fhandler_base *fh;
  for (size_t i = 0; i < size; i++)
    if ((fh = fds[i]) != NULL && !fh->get_close_on_exec ())
      {
	debug_printf ("fd %d (%s)", i, fh->get_name ());
	fh->fixup_before_fork_exec (target_proc_id);
      }
  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "fixup_before_exec");
}

void
dtable::set_file_pointers_for_exec ()
{
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "set_file_pointers_for_exec");
  fhandler_base *fh;
  for (size_t i = 0; i < size; i++)
    if ((fh = fds[i]) != NULL && fh->get_flags () & O_APPEND)
      SetFilePointer (fh->get_handle (), 0, 0, FILE_END);
  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "fixup_before_exec");
}

void
dtable::fixup_after_exec (HANDLE parent)
{
  first_fd_for_open = 0;
  fhandler_base *fh;
  for (size_t i = 0; i < size; i++)
    if ((fh = fds[i]) != NULL)
      {
	fh->clear_readahead ();
	if (fh->get_close_on_exec ())
	  release (i);
	else
	  {
	    fh->fixup_after_exec (parent);
	    if (i == 0)
	      SetStdHandle (std_consts[i], fh->get_io_handle ());
	    else if (i <= 2)
	      SetStdHandle (std_consts[i], fh->get_output_handle ());
	  }
      }
}

void
dtable::fixup_after_fork (HANDLE parent)
{
  fhandler_base *fh;
  for (size_t i = 0; i < size; i++)
    if ((fh = fds[i]) != NULL)
      {
	if (fh->get_close_on_exec () || fh->get_need_fork_fixup ())
	  {
	    debug_printf ("fd %d (%s)", i, fh->get_name ());
	    fh->fixup_after_fork (parent);
	  }
	if (i == 0)
	  SetStdHandle (std_consts[i], fh->get_io_handle ());
	else if (i <= 2)
	  SetStdHandle (std_consts[i], fh->get_output_handle ());
      }
}

int
dtable::vfork_child_dup ()
{
  fhandler_base **newtable;
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "dup");
  newtable = (fhandler_base **) ccalloc (HEAP_ARGV, size, sizeof (fds[0]));
  int res = 1;

  /* Remove impersonation */
  if (cygheap->user.issetuid ())
    RevertToSelf ();

  for (size_t i = 0; i < size; i++)
    if (not_open (i))
      continue;
    else if ((newtable[i] = dup_worker (fds[i])) != NULL)
      newtable[i]->set_close_on_exec (fds[i]->get_close_on_exec ());
    else
      {
	res = 0;
	set_errno (EBADF);
	goto out;
      }

  fds_on_hold = fds;
  fds = newtable;

out:
  /* Restore impersonation */
  if (cygheap->user.issetuid ())
    ImpersonateLoggedOnUser (cygheap->user.token);

  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "dup");
  return 1;
}

void
dtable::vfork_parent_restore ()
{
  SetResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "restore");

  close_all_files ();
  fhandler_base **deleteme = fds;
  assert (fds_on_hold != NULL);
  fds = fds_on_hold;
  fds_on_hold = NULL;
  cfree (deleteme);

  ReleaseResourceLock (LOCK_FD_LIST, WRITE_LOCK | READ_LOCK, "restore");
  return;
}

void
dtable::vfork_child_fixup ()
{
  if (!fds_on_hold)
    return;
  debug_printf ("here");
  fhandler_base **saveme = fds;
  fds = fds_on_hold;

  fhandler_base *fh;
  for (int i = 0; i < (int) cygheap->fdtab.size; i++)
    if ((fh = cygheap->fdtab[i]) != NULL)
      {
	fh->clear_readahead ();
	if (fh->get_close_on_exec ())
	  release (i);
	else
	  {
	    fh->close ();
	    cygheap->fdtab.release (i);
	  }
      }

  fds = saveme;
  cfree (fds_on_hold);
  fds_on_hold = NULL;

  return;
}

#define DEVICE_PREFIX "\\device\\"
#define DEVICE_PREFIX_LEN sizeof (DEVICE_PREFIX) - 1
#define REMOTE "\\Device\\LanmanRedirector\\"
#define REMOTE_LEN sizeof (REMOTE) - 1

static const char *
handle_to_fn (HANDLE h, char *posix_fn)
{
  OBJECT_NAME_INFORMATION *ntfn;
  char fnbuf[32768];

  memset (fnbuf, 0, sizeof (fnbuf));
  ntfn = (OBJECT_NAME_INFORMATION *) fnbuf;
  ntfn->Name.MaximumLength = sizeof (fnbuf) - sizeof (*ntfn);
  ntfn->Name.Buffer = (WCHAR *) (ntfn + 1);

  DWORD res = NtQueryObject (h, ObjectNameInformation, ntfn, sizeof (fnbuf), NULL);

  if (res)
    {
      strcpy (posix_fn, unknown_file);
      debug_printf ("NtQueryObject failed");
      return unknown_file;
    }

  // NT seems to do this on an unopened file
  if (!ntfn->Name.Buffer)
    {
      debug_printf ("nt->Name.Buffer == NULL");
      return NULL;
    }

  ntfn->Name.Buffer[ntfn->Name.Length / sizeof (WCHAR)] = 0;

  char win32_fn[MAX_PATH + 100];
  sys_wcstombs (win32_fn, ntfn->Name.Buffer, ntfn->Name.Length);
  debug_printf ("nt name '%s'", win32_fn);
  if (!strncasematch (win32_fn, DEVICE_PREFIX, DEVICE_PREFIX_LEN)
      || !QueryDosDevice (NULL, fnbuf, sizeof (fnbuf)))
    return strcpy (posix_fn, win32_fn);

  char *p = strchr (win32_fn + DEVICE_PREFIX_LEN, '\\');
  if (!p)
    p = strchr (win32_fn + DEVICE_PREFIX_LEN, '\0');

  int n = p - win32_fn;
  int maxmatchlen = 0;
  char *maxmatchdos = NULL;
  for (char *s = fnbuf; *s; s = strchr (s, '\0') + 1)
    {
      char device[MAX_PATH + 10];
      device[MAX_PATH + 9] = '\0';
      if (strchr (s, ':') == NULL)
	continue;
      if (!QueryDosDevice (s, device, sizeof (device) - 1))
	continue;
      char *q = strrchr (device, ';');
      if (q)
	{
	  char *r = strchr (q, '\\');
	  if (r)
	    strcpy (q, r + 1);
	}
      int devlen = strlen (device);
      if (device[devlen - 1] == '\\')
	device[--devlen] = '\0';
      if (devlen < maxmatchlen)
	continue;
      if (!strncasematch (device, win32_fn, devlen) ||
	  (win32_fn[devlen] != '\0' && win32_fn[devlen] != '\\'))
	continue;
      maxmatchlen = devlen;
      maxmatchdos = s;
      debug_printf ("current match '%s'", device);
    }

  char *w32 = win32_fn;
  if (maxmatchlen)
    {
      n = strlen (maxmatchdos);
      if (maxmatchdos[n - 1] == '\\')
	n--;
      w32 += maxmatchlen - n;
      memcpy (w32, maxmatchdos, n);
      w32[n] = '\\';
    }
  else if (strncasematch (w32, REMOTE, REMOTE_LEN))
    {
      w32 += REMOTE_LEN - 2;
      *w32 = '\\';
      debug_printf ("remote drive");
    }


  debug_printf ("derived path '%s'", w32);
  cygwin_conv_to_full_posix_path (w32, posix_fn);
  return posix_fn;
}