=head1 NAME

libnbd-release-notes-1.20 - release notes for libnbd 1.20

=head1 DESCRIPTION

These are the release notes for libnbd stable release 1.20.
This describes the major changes since 1.18.

libnbd 1.20.0 was released on B<5 April 2024>.

=head2 Security

Fuzzing found and Eric Blake fixed an assertion which could be
triggered by connecting to a malicious server.  This was assigned
CVE-2023-5871 (low severity).  See the announcement here:
L<https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/5CRC7LRTN35WPZZ4BT6NAMH4JGMF47IK/>

If you find a security issue, please read F<SECURITY> in the source
(online here:
L<https://gitlab.com/nbdkit/libnbd/blob/master/SECURITY>).  To
find out about previous security issues in libnbd, see
L<libnbd-security(3)>.

=begin comment

=head2 New APIs

=end comment

=head2 Enhancements to existing APIs

L<nbd_connect_uri(3)> now correctly supports case insensitive URIs.

=head2 Protocol

Improve interop with L<nbd-server(1)> which supports structured
replies but not meta context (Eric Blake).

=head2 Tools

L<nbdinfo(1)> adds support for I<--isnt>, I<--cannot>, I<--hasnt>,
which lets you check if features of an NBD server are I<not>
supported.

L<nbdinfo(1)> adds support for I<--uri> which just prints the
canonical URI of the server.

L<nbdinfo(1)> now prints human sizes for block size constraints (Eric
Blake).

=head2 Language bindings

New L<libnbd-rust(3)> manual page added, providing an overview for
writing Rust programs using libnbd.

Rust documentation has been improved by using a custom translator from
our own documentation format (Perl POD) to rustdoc.

Some Rust compiler warnings were fixed (Eric Blake).

OCaml bindings now support zero-copy in AIO pread and pwrite
functions.  This change is backwards compatible with existing code.
(Thanks Nicolas Ojeda Bar, Anil Madhavapeddy, Simon Cruanes).

OCaml bindings now use C<Gc.finalize> (OCaml-level finalizers instead
of C-level finalizers) which improves compatibility in OCaml 5.1.1 and
above (Guillaume Munch-Maccagnoni).

OCaml E<ge> 4.05 is formally required and checked in F<./configure>.
Previously we did not specify a minimum version of OCaml, but in
practice versions older than 4.05 probably didn't work.

=head2 Tests

Fuzzing approach was changed to use asynchronous commands.  This
improves speed of fuzzing greatly and should find more issues.

Multiple CI fixes (Eric Blake).

Respect the user's choice of qemu-nbd, nbdkit and other binaries from
(eg) S<C<./configure NBDKIT=/some/nbdkit>>.  Previously we would often
test against binaries found on the path even if the user had specified
other binaries to use.

=head2 Other improvements and bug fixes

L<nbdinfo(1)> now gracefully disconnects from the server in error
cases, improving output (Eric Blake).

C<struct nbd_handle> now contains a magic value which is checked on
entry to libnbd, which should identify mistakes where programs calling
libnbd pass in an incorrect pointer.

=head2 Documentation

An example was added of how to use userfaultfd to mmap an NBD-backed
drive.  See F<examples/userfault-map.c> in the libnbd sources.

Documentation of acceptable handle states in the man pages has been
improved.

=head2 Build

F<contrib/libnbd.m4> is a contributed configure test for libnbd (Bruno
Haible).

C<./configure --with-bash-completions> will now fail if the required
bash-completions package is not installed.

=head1 SEE ALSO

L<libnbd(3)>.

=head1 AUTHORS

=begin comment

git shortlog -s v1.18.0..

=end comment

=over 4

=item Eric Blake

=item Richard W.M. Jones

=item Thomas Weißschuh

=back

=head1 COPYRIGHT

Copyright Red Hat
