This patch switches code to SPDX one-line license identifiers according to
https://spdx.dev/learn/handling-license-info/
and replacing long license text headers.
I used C++ format on the first line in style
// SPDX-License-Identifier: <id>
except exported libcryptsetup.h, when only C comments are used.
The only additional changes are:
- switch backend utf8.c from LGPL2+ to LGPL2.1+ (as in systemd)
- add some additional formatting lines.
Add more context to possibly failing kernel keyring routines
in log debug output.
Mostly split debug output for errors while trying to search the kernel
key by description and errors while trying to read/unlink the key
by its id.
Attribute unused is useless and makes code imcomprehensible
when decorates internal functions not exposed via API.
Let's cleanup internal funtion prototypes whenever possible.
The crypt_activate_by_pin_token may be used only from new
dynamicly loadable token plugins.
Also refactors code for dynamically loadable plugins so
that it does not use crypt_token_handler structure anymore.
Old structure remains used only in crypt_token_register call.
Move all keyring functions to one place and separate LUKS2 specific
code to generic handling.
Also fix possible mismatch if volume key is in keyring but it is not native
LUKS2 device (libarary cannot process such a device properly).
Reduce bloated code in low level keyring utilities code.
Move log messages higher the library code.
Also return -ENOTSUP when code was compiled out by configure
option.
