This patch imports the `crypt_sha512.c` file from the musl library.
We need it to incorporate yielding in the `crypt_r` function to avoid
reactor stalls during long hashing computations.
Before this patch series, ScyllaDB used SHA-512 hashing provided
by the `crypt_r` function, which in our case meant using the implementation
from the `libxcrypt` library. Adding yielding to this `libxcrypt`
implementation is problematic, both due to licensing (LGPL) and because the
implementation is split into many functions across multiple files. In
contrast, the SHA-512 implementation from `musl libc` has a more
permissive license and is concise, which makes it easier to incorporate
into the ScyllaDB codebase.
Both `crypt_sha512.c` and musl license are obtained from
git.musl-libc.org:
- https://git.musl-libc.org/cgit/musl/tree/src/crypt/crypt_sha512.c
- https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
Import commit:
commit 1b76ff0767d01df72f692806ee5adee13c67ef88
Author: Alex Rønne Petersen <alex@alexrp.com>
Date: Sun Oct 12 05:35:19 2025 +0200
s390x: shuffle register usage in __tls_get_offset to avoid r0 as address
Refs: scylladb/scylladb#26859
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
