subscriber: clarify the provenance of fmt/time/datetime.rs

tracing-subscriber/src/fmt/time/datetime.rs

@@ -4,16 +4,211 @@ use std::fmt;
 /// formatted string.
 ///
 /// Yes, this exists. Before you have a heart attack, understand that the meat of this is musl's
-/// [`__secs_to_tm`][1] converted to Rust via [c2rust][2] and then cleaned up by hand. All existing
-/// `strftime`-like APIs I found were unable to handle the full range of timestamps representable
-/// by `SystemTime`, including `strftime` itself, since tm.tm_year is an int.
-///
-/// TODO: figure out how to properly attribute the MIT licensed musl project.
+/// [`__secs_to_tm`][1] converted to Rust via [c2rust][2] and then cleaned up by hand as part of
+/// the [kudu-rs project][3], [released under MIT][4].
 ///
 /// [1] http://git.musl-libc.org/cgit/musl/tree/src/time/__secs_to_tm.c
 /// [2] https://c2rust.com/
+/// [3] https://github.com/danburkert/kudu-rs/blob/c9660067e5f4c1a54143f169b5eeb49446f82e54/src/timestamp.rs#L5-L18
+/// [4] https://github.com/tokio-rs/tracing/issues/1644#issuecomment-963888244
+///
+/// All existing `strftime`-like APIs I found were unable to handle the full range of timestamps representable
+/// by `SystemTime`, including `strftime` itself, since tm.tm_year is an int.
+///
+///
+/// musl as a whole is licensed under the following standard MIT license:
+///
+/// ----------------------------------------------------------------------
+/// Copyright © 2005-2020 Rich Felker, et al.
+///
+/// Permission is hereby granted, free of charge, to any person obtaining
+/// a copy of this software and associated documentation files (the
+/// "Software"), to deal in the Software without restriction, including
+/// without limitation the rights to use, copy, modify, merge, publish,
+/// distribute, sublicense, and/or sell copies of the Software, and to
+/// permit persons to whom the Software is furnished to do so, subject to
+/// the following conditions:
+///
+/// The above copyright notice and this permission notice shall be
+/// included in all copies or substantial portions of the Software.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+/// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+/// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+/// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+/// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+/// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+/// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+/// ----------------------------------------------------------------------
+///
+/// Authors/contributors include:
+///
+/// A. Wilcox
+/// Ada Worcester
+/// Alex Dowad
+/// Alex Suykov
+/// Alexander Monakov
+/// Andre McCurdy
+/// Andrew Kelley
+/// Anthony G. Basile
+/// Aric Belsito
+/// Arvid Picciani
+/// Bartosz Brachaczek
+/// Benjamin Peterson
+/// Bobby Bingham
+/// Boris Brezillon
+/// Brent Cook
+/// Chris Spiegel
+/// Clément Vasseur
+/// Daniel Micay
+/// Daniel Sabogal
+/// Daurnimator
+/// David Carlier
+/// David Edelsohn
+/// Denys Vlasenko
+/// Dmitry Ivanov
+/// Dmitry V. Levin
+/// Drew DeVault
+/// Emil Renner Berthing
+/// Fangrui Song
+/// Felix Fietkau
+/// Felix Janda
+/// Gianluca Anzolin
+/// Hauke Mehrtens
+/// He X
+/// Hiltjo Posthuma
+/// Isaac Dunham
+/// Jaydeep Patil
+/// Jens Gustedt
+/// Jeremy Huntwork
+/// Jo-Philipp Wich
+/// Joakim Sindholt
+/// John Spencer
+/// Julien Ramseier
+/// Justin Cormack
+/// Kaarle Ritvanen
+/// Khem Raj
+/// Kylie McClain
+/// Leah Neukirchen
+/// Luca Barbato
+/// Luka Perkov
+/// M Farkas-Dyck (Strake)
+/// Mahesh Bodapati
+/// Markus Wichmann
+/// Masanori Ogino
+/// Michael Clark
+/// Michael Forney
+/// Mikhail Kremnyov
+/// Natanael Copa
+/// Nicholas J. Kain
+/// orc
+/// Pascal Cuoq
+/// Patrick Oppenlander
+/// Petr Hosek
+/// Petr Skocik
+/// Pierre Carrier
+/// Reini Urban
+/// Rich Felker
+/// Richard Pennington
+/// Ryan Fairfax
+/// Samuel Holland
+/// Segev Finer
+/// Shiz
+/// sin
+/// Solar Designer
+/// Stefan Kristiansson
+/// Stefan O'Rear
+/// Szabolcs Nagy
+/// Timo Teräs
+/// Trutz Behn
+/// Valentin Ochs
+/// Will Dietz
+/// William Haddon
+/// William Pitcock
+///
+/// Portions of this software are derived from third-party works licensed
+/// under terms compatible with the above MIT license:
+///
+/// The TRE regular expression implementation (src/regex/reg* and
+/// src/regex/tre*) is Copyright © 2001-2008 Ville Laurikari and licensed
+/// under a 2-clause BSD license (license text in the source files). The
+/// included version has been heavily modified by Rich Felker in 2012, in
+/// the interests of size, simplicity, and namespace cleanliness.
+///
+/// Much of the math library code (src/math/* and src/complex/*) is
+/// Copyright © 1993,2004 Sun Microsystems or
+/// Copyright © 2003-2011 David Schultz or
+/// Copyright © 2003-2009 Steven G. Kargl or
+/// Copyright © 2003-2009 Bruce D. Evans or
+/// Copyright © 2008 Stephen L. Moshier or
+/// Copyright © 2017-2018 Arm Limited
+/// and labelled as such in comments in the individual source files. All
+/// have been licensed under extremely permissive terms.
+///
+/// The ARM memcpy code (src/string/arm/memcpy.S) is Copyright © 2008
+/// The Android Open Source Project and is licensed under a two-clause BSD
+/// license. It was taken from Bionic libc, used on Android.
+///
+/// The AArch64 memcpy and memset code (src/string/aarch64/*) are
+/// Copyright © 1999-2019, Arm Limited.
+///
+/// The implementation of DES for crypt (src/crypt/crypt_des.c) is
+/// Copyright © 1994 David Burren. It is licensed under a BSD license.
+///
+/// The implementation of blowfish crypt (src/crypt/crypt_blowfish.c) was
+/// originally written by Solar Designer and placed into the public
+/// domain. The code also comes with a fallback permissive license for use
+/// in jurisdictions that may not recognize the public domain.
+///
+/// The smoothsort implementation (src/stdlib/qsort.c) is Copyright © 2011
+/// Valentin Ochs and is licensed under an MIT-style license.
+///
+/// The x86_64 port was written by Nicholas J. Kain and is licensed under
+/// the standard MIT terms.
+///
+/// The mips and microblaze ports were originally written by Richard
+/// Pennington for use in the ellcc project. The original code was adapted
+/// by Rich Felker for build system and code conventions during upstream
+/// integration. It is licensed under the standard MIT terms.
+///
+/// The mips64 port was contributed by Imagination Technologies and is
+/// licensed under the standard MIT terms.
+///
+/// The powerpc port was also originally written by Richard Pennington,
+/// and later supplemented and integrated by John Spencer. It is licensed
+/// under the standard MIT terms.
+///
+/// All other files which have no copyright comments are original works
+/// produced specifically for use as part of this library, written either
+/// by Rich Felker, the main author of the library, or by one or more
+/// contibutors listed above. Details on authorship of individual files
+/// can be found in the git version control history of the project. The
+/// omission of copyright and license comments in each file is in the
+/// interest of source tree size.
+///
+/// In addition, permission is hereby granted for all public header files
+/// (include/* and arch/*/bits/*) and crt files intended to be linked into
+/// applications (crt/*, ldso/dlstart.c, and arch/*/crt_arch.h) to omit
+/// the copyright notice and permission notice otherwise required by the
+/// license, and to use these files without any requirement of
+/// attribution. These files include substantial contributions from:
+///
+/// Bobby Bingham
+/// John Spencer
+/// Nicholas J. Kain
+/// Rich Felker
+/// Richard Pennington
+/// Stefan Kristiansson
+/// Szabolcs Nagy
+///
+/// all of whom have explicitly granted such permission.
 ///
-/// This is directly copy-pasted from https://github.com/danburkert/kudu-rs/blob/c9660067e5f4c1a54143f169b5eeb49446f82e54/src/timestamp.rs#L5-L18
+/// This file previously contained text expressing a belief that most of
+/// the files covered by the above exception were sufficiently trivial not
+/// to be subject to copyright, resulting in confusion over whether it
+/// negated the permissions granted in the license. In the spirit of
+/// permissive licensing, and of not having licensing issues being an
+/// obstacle to adoption, that text has been removed.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) struct DateTime {
     year: i64,