MFC r359978:

Fix -Wvoid-pointer-to-enum-cast warnings.

This pattern is used in callbacks with void * data arguments and seems
both relatively uncommon and relatively harmless. Silence the warning
by casting through uintptr_t.

This warning is on by default in Clang 11.

Reviewed by: arichardson
Obtained from: CheriBSD (partial)
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24425

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

libc: spelling fixes.

Mostly on comments.

Add declarations to netdb_private.h to eliminate -Wmissing-prototypes warnings.

- When there is no room for returning the result, nss backend
have to return ERANGE and terminate with NS_RETURN.
- When gethostbyname_r(3) and the friends end with an error,
set errno to the value nss backend returns, and return errno
value.

PR: kern/131623
MFC after: 2 weeks

- Extend the nsswitch to support Services, Protocols and Rpc
databases.
- Make nsswitch support caching.

Submitted by: Michael Bushkov <bushman__at__rsu.ru>
Sponsored by: Google Summer of Code 2005

- make reentrant version of netdb functions glibc style API, and
expose them to outside of libc.
- make netdb functions NSS friendly.

Reviewed by: arch@ and current@ (no objection)

- Remove padding for ABI compatibility of n_net member from struct
netent.
- Change 1st argument of getnetbyaddr() to an uint32_t on 64 bit
arch as well to confirm to POSIX-2001.

These changes break ABI compatibility on 64 bit arch.
There is similar padding issue for ai_addrlen of struct addrinfo.
However, it is leaved as is for now.

Discussed on: arch@, standards@ and current@
X-MFC after: never

- The ai_addrlen of a struct addrinfo used to be a size_t, per
RFC 2553. In XNS5.2, and subsequently in POSIX-2001 and RFC
3493, it was changed to a socklen_t. And, the n_net of a
struct netent used to be an unsigned long integer. In XNS5,
and subsequently in POSIX-2001, it was changed to an uint32_t.
To accomodate for this while preserving ABI compatibility with
the old interface, we need to prepend or append 32 bits of
padding, depending on the (LP64) architecture's endianness.
- Correct 1st argument of getnetbyaddr() to uint32_t on 32
bit arch. Stay as is on 64 bit arch for ABI backward
compatibility for now.

Reviewed by: das, peter
MFC after: 2 weeks

make getnetby*() thread-safe.

hide implementation specific internal functions from netdb.h.
it is needed to make get{host,net}by*() thread-safe.

Catch up with nsdispatch.c: nsdispatch(3) is now `hidden' by
namespace.h.

Sponsored by: DARPA, Network Associates Laboratories

Fix the style of the SCM ID's.
I believe have made all of libc .c's as consistent as possible.

getnetbyaddr() should be serviced by the "networks" database.

Remove _THREAD_SAFE and make libc thread-safe by default by
adding (weak definitions to) stubs for some of the pthread
functions. If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
__sys_foo - actual system call
_foo - weak definition to __sys_foo
foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo. In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde). All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes. <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE. We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by: -arch

Add nsswitch support. By creating an /etc/nsswitch.conf file, you can
configure FreeBSD so that various databases such as passwd and group can be
looked up using flat files, NIS, or Hesiod.

= Hesiod has been added to libc (see hesiod(3)).

= A library routine for parsing nsswitch.conf and invoking callback
functions as specified has been added to libc (see nsdispatch(3)).

= The following C library functions have been modified to use nsdispatch:
. getgrent, getgrnam, getgrgid
. getpwent, getpwnam, getpwuid
. getusershell
. getaddrinfo
. gethostbyname, gethostbyname2, gethostbyaddr
. getnetbyname, getnetbyaddr
. getipnodebyname, getipnodebyaddr, getnodebyname, getnodebyaddr

= host.conf has been removed from src/etc. rc.network has been modified
to warn that host.conf is no longer used at boot time. In addition, if
there is a host.conf but no nsswitch.conf, the latter is created at boot
time from the former.

Obtained from: NetBSD

Add unsigned char cast to isalpha

$Id$ -> $FreeBSD$

Merge in bind-4.9.6 resolver changes. Note that they resolve the
overflow problem differently.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Here goes.. Bring the 4.9.5-P1 resolver into -current. This has the
DNSSEC stuff, among other things. There are also some renamed functions,
I've left out the res_stubs.c from this commit in case cvs bombs out..

Merge in bind-4.9.4-P1 resolver...

General -Wall warning cleanup, part I.
Submitted-By: Kent Vander Velden <graphix@iastate.edu>

Remove trailing whitespace.

Sicnce this code shares the same fragment as gethostnamaddr:
Change strtok() to strsep(), cause memory corruption for all
programs which use strtok() too in the same time.
Fix potential NULL reference, depends of /etc/hosts.conf format
Fix the bug when service name fetched always from beginning of the line,
not from parsed token.

Use same configuration file, /etc/host.conf, for both gethost* and
getnet* configuration. (It's highly unlikely that you'd want to do
something different, and network lookups aren't common enough to justify
their own configuration file.)

get* rework and new bind code