common: Add support for the new extended private key format.
* agent/findkey.c (write_extended_private_key): New function. (agent_write_private_key): Detect if an existing file is in extended format and update the key within if it is. (read_key_file): Handle the new format. * agent/keyformat.txt: Document the new format. * common/Makefile.am: Add the new files. * common/private-keys.c: New file. * common/private-keys.h: Likewise. * common/t-private-keys.c: Likewise. * common/util.h (alphap, alnump): New macros. * tests/migrations: Add test demonstrating that we can cope with the new format.
GnuPG 2.3+ will use a new format to store private keys that is both
more flexible and easier to read and edit by human beings. The new
format stores name,value-pairs using the common mail and http header
This patch adds the parser and support code and prepares GnuPG 2.1 for
the new format.
- Signed-off-by: Justus Winter <email@example.com>