diff options
Diffstat (limited to 'dbus/dbus-internals.c')
| -rw-r--r-- | dbus/dbus-internals.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/dbus/dbus-internals.c b/dbus/dbus-internals.c index 8567ebb5..707b4005 100644 --- a/dbus/dbus-internals.c +++ b/dbus/dbus-internals.c @@ -413,6 +413,258 @@ _dbus_string_array_contains (const char **array, return FALSE; } +/** + * Generates a new UUID. If you change how this is done, + * there's some text about it in the spec that should also change. + * + * @param uuid the uuid to initialize + */ +void +_dbus_generate_uuid (DBusGUID *uuid) +{ + long now; + char *p; + int ts_size; + + _dbus_get_current_time (&now, NULL); + + uuid->as_uint32s[0] = now; + + ts_size = sizeof (uuid->as_uint32s[0]); + p = ((char*)uuid->as_bytes) + ts_size; + + _dbus_generate_random_bytes_buffer (p, + sizeof (uuid->as_bytes) - ts_size); +} + +/** + * Hex-encode a UUID. + * + * @param uuid the uuid + * @param encoded string to append hex uuid to + * @returns #FALSE if no memory + */ +dbus_bool_t +_dbus_uuid_encode (const DBusGUID *uuid, + DBusString *encoded) +{ + DBusString binary; + _dbus_string_init_const_len (&binary, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES); + return _dbus_string_hex_encode (&binary, 0, encoded, _dbus_string_get_length (encoded)); +} + +static dbus_bool_t +_dbus_read_uuid_file_without_creating (const DBusString *filename, + DBusGUID *uuid, + DBusError *error) +{ + DBusString contents; + DBusString decoded; + int end; + + _dbus_string_init (&contents); + _dbus_string_init (&decoded); + + if (!_dbus_file_get_contents (&contents, filename, error)) + goto error; + + _dbus_string_chop_white (&contents); + + if (_dbus_string_get_length (&contents) != DBUS_UUID_LENGTH_HEX) + { + dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, + "UUID file '%s' should contain a hex string of length %d, not length %d, with no other text", + _dbus_string_get_const_data (filename), + DBUS_UUID_LENGTH_HEX, + _dbus_string_get_length (&contents)); + goto error; + } + + if (!_dbus_string_hex_decode (&contents, 0, &end, &decoded, 0)) + { + _DBUS_SET_OOM (error); + goto error; + } + + if (end == 0) + { + dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, + "UUID file '%s' contains invalid hex data", + _dbus_string_get_const_data (filename)); + goto error; + } + + if (_dbus_string_get_length (&decoded) != DBUS_UUID_LENGTH_BYTES) + { + dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT, + "UUID file '%s' contains %d bytes of hex-encoded data instead of %d", + _dbus_string_get_const_data (filename), + _dbus_string_get_length (&decoded), + DBUS_UUID_LENGTH_BYTES); + goto error; + } + + _dbus_string_copy_to_buffer (&decoded, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES); + + _dbus_string_free (&decoded); + _dbus_string_free (&contents); + + _DBUS_ASSERT_ERROR_IS_CLEAR (error); + + return TRUE; + + error: + _DBUS_ASSERT_ERROR_IS_SET (error); + _dbus_string_free (&contents); + _dbus_string_free (&decoded); + return FALSE; +} + +static dbus_bool_t +_dbus_create_uuid_file_exclusively (const DBusString *filename, + DBusGUID *uuid, + DBusError *error) +{ + DBusString encoded; + + _dbus_string_init (&encoded); + + _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; + + + _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; +} + +/** + * Reads (and optionally writes) a uuid to a file. Initializes the uuid + * unless an error is returned. + * + * @param filename the name of the file + * @param uuid uuid to be initialized with the loaded uuid + * @param create_if_not_found #TRUE to create a new uuid and save it if the file doesn't exist + * @param error the error return + * @returns #FALSE if the error is set + */ +dbus_bool_t +_dbus_read_uuid_file (const DBusString *filename, + DBusGUID *uuid, + dbus_bool_t create_if_not_found, + DBusError *error) +{ + DBusError read_error; + + dbus_error_init (&read_error); + + if (_dbus_read_uuid_file_without_creating (filename, uuid, &read_error)) + return TRUE; + + if (!create_if_not_found) + { + dbus_move_error (&read_error, error); + return FALSE; + } + + /* If the file exists and contains junk, we want to keep that error + * message instead of overwriting it with a "file exists" error + * message when we try to write + */ + if (dbus_error_has_name (&read_error, DBUS_ERROR_INVALID_FILE_CONTENT)) + { + dbus_move_error (&read_error, error); + return FALSE; + } + else + { + dbus_error_free (&read_error); + return _dbus_create_uuid_file_exclusively (filename, uuid, error); + } +} + +_DBUS_DEFINE_GLOBAL_LOCK (machine_uuid); +static int machine_uuid_initialized_generation = 0; +static DBusGUID machine_uuid; + +/** + * Gets the hex-encoded UUID of the machine this function is + * executed on. This UUID is guaranteed to be the same for a given + * machine at least until it next reboots, though it also + * makes some effort to be the same forever, it may change if the + * machine is reconfigured or its hardware is modified. + * + * @param uuid_str string to append hex-encoded machine uuid to + * @returns #FALSE if no memory + */ +dbus_bool_t +_dbus_get_local_machine_uuid_encoded (DBusString *uuid_str) +{ + dbus_bool_t ok; + + _DBUS_LOCK (machine_uuid); + if (machine_uuid_initialized_generation != _dbus_current_generation) + { + DBusError error; + dbus_error_init (&error); + if (!_dbus_read_local_machine_uuid (&machine_uuid, FALSE, + &error)) + { +#ifndef DBUS_BUILD_TESTS + /* For the test suite, we may not be installed so just continue silently + * here. But in a production build, we want to be nice and loud about + * this. + */ + _dbus_warn ("D-Bus library appears to be incorrectly set up; failed to read machine uuid: %s\n", + error.message); + _dbus_warn ("See the manual page for dbus-uuidgen to correct this issue.\n"); + _dbus_warn ("Continuing with a bogus made-up machine UUID, which may cause problems."); +#endif + + dbus_error_free (&error); + + _dbus_generate_uuid (&machine_uuid); + } + } + + ok = _dbus_uuid_encode (&machine_uuid, uuid_str); + + _DBUS_UNLOCK (machine_uuid); + + return ok; +} + #ifdef DBUS_BUILD_TESTS /** * Returns a string describing the given name. |