fhandler_disk_file.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

 * This shouldn't break many apps but denying all locking
 * would.
 * For now just convert to Win32 locks and hope for the best.
 */

int
fhandler_disk_file::lock (int cmd, struct flock *fl)
{
  __off64_t win32_start;
  int win32_len;
  DWORD win32_upper;
  __off64_t startpos;

  /*
   * We don't do getlck calls yet.
   */

  if (cmd == F_GETLK)
    {
      set_errno (ENOSYS);
      return -1;
    }

  /*
   * Calculate where in the file to start from,
   * then adjust this by fl->l_start.
   */

  switch (fl->l_whence)
    {
      case SEEK_SET:
	startpos = 0;
	break;
      case SEEK_CUR:
	if ((startpos = lseek (0, SEEK_CUR)) == ILLEGAL_SEEK)
	  return -1;
	break;
      case SEEK_END:
	{
	  BY_HANDLE_FILE_INFORMATION finfo;
	  if (GetFileInformationByHandle (get_handle (), &finfo) == 0)
	    {
	      __seterrno ();
	      return -1;
	    }
	  startpos = ((__off64_t)finfo.nFileSizeHigh << 32)
		     + finfo.nFileSizeLow;
	  break;
	}
      default:
	set_errno (EINVAL);
	return -1;
    }

  /*
   * Now the fun starts. Adjust the start and length
   *  fields until they make sense.
   */

  win32_start = startpos + fl->l_start;
  if (fl->l_len < 0)
    {
      win32_start -= fl->l_len;
      win32_len = -fl->l_len;
    }
  else
    win32_len = fl->l_len;

  if (win32_start < 0)
    {
      /* watch the signs! */
      win32_len -= -win32_start;
      if (win32_len <= 0)
	{
	  /* Failure ! */
	  set_errno (EINVAL);
	  return -1;
	}
      win32_start = 0;
    }

  /*
   * Special case if len == 0 for POSIX means lock
   * to the end of the entire file (and all future extensions).
   */
  if (win32_len == 0)
    {
      win32_len = 0xffffffff;
      win32_upper = wincap.lock_file_highword ();
    }
  else
    win32_upper = 0;

  BOOL res;

  if (wincap.has_lock_file_ex ())
    {
      DWORD lock_flags = (cmd == F_SETLK) ? LOCKFILE_FAIL_IMMEDIATELY : 0;
      lock_flags |= (fl->l_type == F_WRLCK) ? LOCKFILE_EXCLUSIVE_LOCK : 0;

      OVERLAPPED ov;

      ov.Internal = 0;
      ov.InternalHigh = 0;
      ov.Offset = (DWORD)win32_start;
      ov.OffsetHigh = 0;
      ov.hEvent = (HANDLE) 0;

      if (fl->l_type == F_UNLCK)
	{
	  res = UnlockFileEx (get_handle (), 0, (DWORD)win32_len, win32_upper, &ov);
	}
      else
	{
	  res = LockFileEx (get_handle (), lock_flags, 0, (DWORD)win32_len,
							win32_upper, &ov);
	  /* Deal with the fail immediately case. */
	  /*
	   * FIXME !! I think this is the right error to check for
	   * but I must admit I haven't checked....
	   */
	  if ((res == 0) && (lock_flags & LOCKFILE_FAIL_IMMEDIATELY) &&
			    (GetLastError () == ERROR_LOCK_FAILED))
	    {
	      set_errno (EAGAIN);
	      return -1;
	    }
	}
    }
  else
    {
      /* Windows 95 -- use primitive lock call */
      if (fl->l_type == F_UNLCK)
	res = UnlockFile (get_handle (), (DWORD)win32_start, 0, (DWORD)win32_len,
							win32_upper);
      else
	res = LockFile (get_handle (), (DWORD)win32_start, 0, (DWORD)win32_len, win32_upper);
    }

  if (res == 0)
    {
      __seterrno ();
      return -1;
    }

  return 0;
}

DIR *
fhandler_disk_file::opendir (path_conv& real_name)
{
  DIR *dir;
  DIR *res = NULL;
  size_t len;

  if (!real_name.isdir ())
    set_errno (ENOTDIR);
  else if ((len = strlen (real_name))> MAX_PATH - 3)
    set_errno (ENAMETOOLONG);
  else if ((dir = (DIR *) malloc (sizeof (DIR))) == NULL)
    set_errno (ENOMEM);
  else if ((dir->__d_dirname = (char *) malloc (len + 3)) == NULL)
    {
      free (dir);
      set_errno (ENOMEM);
    }
  else if ((dir->__d_dirent =
	    (struct dirent *) malloc (sizeof (struct dirent))) == NULL)
    {
      free (dir->__d_dirname);
      free (dir);
      set_errno (ENOMEM);
    }
  else
    {
      strcpy (dir->__d_dirname, real_name.get_win32 ());
      dir->__d_dirent->d_version = __DIRENT_VERSION;
      cygheap_fdnew fd;
      fd = this;
      fd->set_nohandle (true);
      dir->__d_dirent->d_fd = fd;
      dir->__d_u.__d_data.__fh = this;
      /* FindFirstFile doesn't seem to like duplicate /'s. */
      len = strlen (dir->__d_dirname);
      if (len == 0 || SLASH_P (dir->__d_dirname[len - 1]))
	strcat (dir->__d_dirname, "*");
      else
	strcat (dir->__d_dirname, "\\*");  /**/
      dir->__d_cookie = __DIRENT_COOKIE;
      dir->__d_u.__d_data.__handle = INVALID_HANDLE_VALUE;
      dir->__d_position = 0;
      dir->__d_dirhash = get_namehash ();

      res = dir;
    }

  syscall_printf ("%p = opendir (%s)", res, get_name ());
  return res;
}

struct dirent *
fhandler_disk_file::readdir (DIR *dir)
{
  WIN32_FIND_DATA buf;
  HANDLE handle;
  struct dirent *res = NULL;

  if (dir->__d_u.__d_data.__handle == INVALID_HANDLE_VALUE
      && dir->__d_position == 0)
    {
      handle = FindFirstFileA (dir->__d_dirname, &buf);
      DWORD lasterr = GetLastError ();
      dir->__d_u.__d_data.__handle = handle;
      if (handle == INVALID_HANDLE_VALUE && (lasterr != ERROR_NO_MORE_FILES))
	{
	  seterrno_from_win_error (__FILE__, __LINE__, lasterr);
	  return res;
	}
    }
  else if (dir->__d_u.__d_data.__handle == INVALID_HANDLE_VALUE)
    {
      return res;
    }
  else if (!FindNextFileA (dir->__d_u.__d_data.__handle, &buf))
    {
      DWORD lasterr = GetLastError ();
      (void) FindClose (dir->__d_u.__d_data.__handle);
      dir->__d_u.__d_data.__handle = INVALID_HANDLE_VALUE;
      /* POSIX says you shouldn't set errno when readdir can't
	 find any more files; so, if another error we leave it set. */
      if (lasterr != ERROR_NO_MORE_FILES)
	  seterrno_from_win_error (__FILE__, __LINE__, lasterr);
      syscall_printf ("%p = readdir (%p)", res, dir);
      return res;
    }

  /* We get here if `buf' contains valid data.  */
  strcpy (dir->__d_dirent->d_name, buf.cFileName);

  /* Check for Windows shortcut. If it's a Cygwin or U/WIN
     symlink, drop the .lnk suffix. */
  if (buf.dwFileAttributes & FILE_ATTRIBUTE_READONLY)
    {
      char *c = dir->__d_dirent->d_name;
      int len = strlen (c);
      if (strcasematch (c + len - 4, ".lnk"))
	{
	  char fbuf[MAX_PATH + 1];
	  strcpy (fbuf, dir->__d_dirname);
	  strcpy (fbuf + strlen (fbuf) - 1, dir->__d_dirent->d_name);
	  path_conv fpath (fbuf, PC_SYM_NOFOLLOW);
	  if (fpath.issymlink ())
	    c[len - 4] = '\0';
	}
    }

  dir->__d_position++;
  res = dir->__d_dirent;
  syscall_printf ("%p = readdir (%p) (%s)",
		  &dir->__d_dirent, dir, buf.cFileName);
  return res;
}

__off64_t
fhandler_disk_file::telldir (DIR *dir)
{
  return dir->__d_position;
}

void
fhandler_disk_file::seekdir (DIR *dir, __off64_t loc)
{
    rewinddir (dir);
    while (loc > dir->__d_position)
      if (!readdir (dir))
	break;
}

void
fhandler_disk_file::rewinddir (DIR *dir)
{
  if (dir->__d_u.__d_data.__handle != INVALID_HANDLE_VALUE)
    {
      (void) FindClose (dir->__d_u.__d_data.__handle);
      dir->__d_u.__d_data.__handle = INVALID_HANDLE_VALUE;
    }
  dir->__d_position = 0;
}

int
fhandler_disk_file::closedir (DIR *dir)
{
  int res = 0;
  if (dir->__d_u.__d_data.__handle != INVALID_HANDLE_VALUE &&
      FindClose (dir->__d_u.__d_data.__handle) == 0)
    {
      __seterrno ();
      res = -1;
    }
  syscall_printf ("%d = closedir (%p)", res, dir);
  return 0;
}

fhandler_cygdrive::fhandler_cygdrive (int unit) :
  fhandler_disk_file (FH_CYGDRIVE), unit (unit), ndrives (0), pdrive (NULL)
{
}

#define DRVSZ sizeof ("x:\\")
void
fhandler_cygdrive::set_drives ()
{
  const int len = 1 + 26 * DRVSZ;
  char *p = (char *) crealloc ((void *) win32_path_name,
				sizeof (".") + sizeof ("..") + len);

  win32_path_name = pdrive = p;
  strcpy (p, ".");
  strcpy (p + sizeof ("."), "..");
  p += sizeof (".") + sizeof ("..");
  ndrives = GetLogicalDriveStrings (len, p) / DRVSZ;
}

int
fhandler_cygdrive::fstat (struct __stat64 *buf, path_conv *pc)
{
  if (!iscygdrive_root ())
    return fhandler_disk_file::fstat (buf, pc);
  buf->st_mode = S_IFDIR | 0555;
  if (!ndrives)
    set_drives ();
  buf->st_nlink = ndrives;
  return 0;
}

DIR *
fhandler_cygdrive::opendir (path_conv& real_name)
{
  DIR *dir;

  dir = fhandler_disk_file::opendir (real_name);
  if (dir && iscygdrive_root () && !ndrives)
    set_drives ();

  return dir;
}

struct dirent *
fhandler_cygdrive::readdir (DIR *dir)
{
  if (!iscygdrive_root ())
    return fhandler_disk_file::readdir (dir);
  if (!pdrive || !*pdrive)
    {
      set_errno (ENMFILE);
      return NULL;
    }
  else if (dir->__d_position > 1
	   && GetFileAttributes (pdrive) == INVALID_FILE_ATTRIBUTES)
    {
      pdrive = strchr (pdrive, '\0') + 1;
      return readdir (dir);
    }
  else if (*pdrive == '.')
    strcpy (dir->__d_dirent->d_name, pdrive);
  else
    {
      *dir->__d_dirent->d_name = cyg_tolower (*pdrive);
      dir->__d_dirent->d_name[1] = '\0';
    }
  dir->__d_position++;
  pdrive = strchr (pdrive, '\0') + 1;
  syscall_printf ("%p = readdir (%p) (%s)", &dir->__d_dirent, dir,
		  dir->__d_dirent->d_name);
  return dir->__d_dirent;
}

__off64_t
fhandler_cygdrive::telldir (DIR *dir)
{
  return fhandler_disk_file::telldir (dir);
}

void
fhandler_cygdrive::seekdir (DIR *dir, __off64_t loc)
{
  if (!iscygdrive_root ())
    return fhandler_disk_file::seekdir (dir, loc);

  for (pdrive = win32_path_name, dir->__d_position = -1; *pdrive;
       pdrive = strchr (pdrive, '\0') + 1)
    if (++dir->__d_position >= loc)
      break;

  return;
}

void
fhandler_cygdrive::rewinddir (DIR *dir)
{
  if (!iscygdrive_root ())
    return fhandler_disk_file::rewinddir (dir);
  pdrive = win32_path_name;
  dir->__d_position = 0;
  return;
}

int
fhandler_cygdrive::closedir (DIR *dir)
{
  if (!iscygdrive_root ())
    return fhandler_disk_file::closedir (dir);
  pdrive = win32_path_name;
  return -1;
}