static dbus_bool_t
_dbus_create_uuid_file_exclusively (const DBusString *filename,
DBusGUID *uuid,
DBusError *error)
{
DBusString encoded;
if (!_dbus_string_init (&encoded))
{
_DBUS_SET_OOM (error);
return FALSE;
}
_dbus_generate_uuid (uuid);
if (!_dbus_uuid_encode (uuid, &encoded))
{
_DBUS_SET_OOM (error);
goto error;
}
/* FIXME this is racy; we need a save_file_exclusively
* function. But in practice this should be fine for now.
*
* - first be sure we can create the file and it
* doesn't exist by creating it empty with O_EXCL
* - then create it by creating a temporary file and
* overwriting atomically with rename()
*/
if (!_dbus_create_file_exclusively (filename, error))
goto error;
if (!_dbus_string_append_byte (&encoded, '\n'))
{
_DBUS_SET_OOM (error);
goto error;
}
if (!_dbus_string_save_to_file (&encoded, filename, error))
goto error;
if (!_dbus_make_file_world_readable (filename, error))
goto error;
_dbus_string_free (&encoded);
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
return TRUE;
error:
_DBUS_ASSERT_ERROR_IS_SET (error);
_dbus_string_free (&encoded);
return FALSE;
}
/**
* Writes a string out to a file. If the file exists,
* it will be atomically overwritten by the new data.
*
* @param str the string to write out
* @param filename the file to save string to
* @param world_readable if true, ensure file is world readable
* @param error error to be filled in on failure
* @returns #FALSE on failure
*/
dbus_bool_t
_dbus_string_save_to_file (const DBusString *str,
const DBusString *filename,
dbus_bool_t world_readable,
DBusError *error)
{
HANDLE hnd;
int bytes_to_write;
const char *filename_c;
DBusString tmp_filename;
const char *tmp_filename_c;
int total;
const char *str_c;
dbus_bool_t need_unlink;
dbus_bool_t retval;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
hnd = INVALID_HANDLE_VALUE;
retval = FALSE;
need_unlink = FALSE;
if (!_dbus_string_init (&tmp_filename))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
return FALSE;
}
if (!_dbus_string_copy (filename, 0, &tmp_filename, 0))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&tmp_filename);
return FALSE;
}
if (!_dbus_string_append (&tmp_filename, "."))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&tmp_filename);
return FALSE;
}
#define N_TMP_FILENAME_RANDOM_BYTES 8
if (!_dbus_generate_random_ascii (&tmp_filename, N_TMP_FILENAME_RANDOM_BYTES))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&tmp_filename);
return FALSE;
}
filename_c = _dbus_string_get_const_data (filename);
tmp_filename_c = _dbus_string_get_const_data (&tmp_filename);
/* TODO - support world-readable in an atomic fashion */
hnd = CreateFileA (tmp_filename_c, GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL, CREATE_NEW, FILE_ATTRIBUTE_NORMAL,
INVALID_HANDLE_VALUE);
if (hnd == INVALID_HANDLE_VALUE)
{
char *emsg = _dbus_win_error_string (GetLastError ());
dbus_set_error (error, _dbus_win_error_from_last_error (),
"Could not create \"%s\": %s", filename_c, emsg);
_dbus_win_free_error_string (emsg);
goto out;
}
if (world_readable)
{
if (! _dbus_make_file_world_readable (&tmp_filename, error))
goto out;
}
_dbus_verbose ("tmp file %s hnd %p opened\n", tmp_filename_c, hnd);
need_unlink = TRUE;
total = 0;
bytes_to_write = _dbus_string_get_length (str);
str_c = _dbus_string_get_const_data (str);
while (total < bytes_to_write)
{
DWORD bytes_written;
BOOL res;
res = WriteFile (hnd, str_c + total, bytes_to_write - total,
&bytes_written, NULL);
if (res == 0 || bytes_written <= 0)
{
char *emsg = _dbus_win_error_string (GetLastError ());
dbus_set_error (error, _dbus_win_error_from_last_error (),
"Could not write to %s: %s", tmp_filename_c, emsg);
_dbus_win_free_error_string (emsg);
goto out;
}
total += bytes_written;
}
if (CloseHandle (hnd) == 0)
{
char *emsg = _dbus_win_error_string (GetLastError ());
dbus_set_error (error, _dbus_win_error_from_last_error (),
"Could not close file %s: %s", tmp_filename_c, emsg);
_dbus_win_free_error_string (emsg);
goto out;
}
hnd = INVALID_HANDLE_VALUE;
/* Unlike rename(), MoveFileEx() can replace existing files */
if (!MoveFileExA (tmp_filename_c, filename_c, MOVEFILE_REPLACE_EXISTING))
{
char *emsg = _dbus_win_error_string (GetLastError ());
dbus_set_error (error, _dbus_win_error_from_last_error (),
"Could not rename %s to %s: %s",
tmp_filename_c, filename_c, emsg);
_dbus_win_free_error_string (emsg);
goto out;
}
need_unlink = FALSE;
retval = TRUE;
out:
/* close first, then unlink */
if (hnd != INVALID_HANDLE_VALUE)
CloseHandle (hnd);
if (need_unlink && DeleteFileA (tmp_filename_c) == 0)
{
char *emsg = _dbus_win_error_string (GetLastError ());
_dbus_verbose ("Failed to unlink temp file %s: %s", tmp_filename_c,
emsg);
_dbus_win_free_error_string (emsg);
}
_dbus_string_free (&tmp_filename);
if (!retval)
_DBUS_ASSERT_ERROR_IS_SET (error);
return retval;
}
