We use common libcryptsetup-token.sym version script that contain
all symbols, but some of them are optional.
As clang linker treats missing symbols as errors, the linker
phase for ssh token fails as optional cryptsetup_token_buffer_free
is not defined.
(Most of distros has this option still disabled, though).
As the sym file is also example for token authors, removing symbols
there is not an option. For clang, we can use --undefined-version option,
but it is not supported by other linkers, so it requires non-trivial
checks for usable LDFLAGS (for both autoconf and meson).
Instead, fix it by simply defining the symbol in ssh token, which
duplicates the internal libcryptsetup functionality.
Fixes: #830
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.
Provides example of loadable token handler for activation
json validation and metadata dump.
For creating new ssh example token use special cryptsetup-ssh
binary.
