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

Remove names from some prototypes

Add declarations to eliminate -Wmissing-prototypes warnings

Reduce the size of the interposing table and amount of
cancellation-handling code in the libthr. Translate some syscalls
into their more generic counterpart, and remove translated syscalls
from the table.

List of the affected syscalls:
creat, open -> openat
raise -> thr_kill
sleep, usleep -> nanosleep
pause -> sigsuspend
wait, wait3, waitpid -> wait4

Suggested and reviewed by: jilles (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Fix known issues which blow up the process after dlopen("libthr.so")
(or loading a dso linked to libthr.so into process which was not
linked against threading library).

- Remove libthr interposers of the libc functions, including
__error(). Instead, functions calls are indirected through the
interposing table, similar to how pthread stubs in libc are already
done. Libc by default points either to syscall trampolines or to
existing libc implementations. On libthr load, libthr rewrites the
pointers to the cancellable implementations already in libthr. The
interposition table is separate from pthreads stubs indirection
table to not pull pthreads stubs into static binaries.

- Postpone the malloc(3) internal mutexes initialization until libthr
is loaded. This avoids recursion between calloc(3) and static
pthread_mutex_t initialization.

- Reinstall signal handlers with wrapper on libthr load. The
_rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2)
when libthr is statically referenced from the main binary.

In the process, fix openat(2), swapcontext(2) and setcontext(2)
interposing. The libc symbols were exported at different versions
than libthr interposers. Export both libc and libthr versions from
libc now, with default set to the higher version from libthr.

Remove unused and disconnected swapcontext(3) userspace implementation
from libc/gen.

No objections from: deischen
Tested by: pho, antoine (exp-run) (previous versions)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Fix many "function declaration isn't a prototype" warnings in libc.

I've only fixed code that seems to be written by `us'. There are still
many warnings like this present in resolv/, rpc/, stdtime/ and yp/.

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Make usleep() overridable by the thread libraries so they can provide
cancellation points.

Noticed by: phk

Use `useconds_t' instead of `u_int' or `unsigned int' where appropriate.

Fix SCM ID's.

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

Simplify sytem call renaming. Instead of _foo() <-- _libc_foo <-- foo(),
just use _foo() <-- foo(). In the case of a libpthread that doesn't do
call conversion (such as linuxthreads and our upcoming libpthread), this
is adequate. In the case of libc_r, we still need three names, which are
now _thread_sys_foo() <-- _foo() <-- foo().

Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(),
nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo().

Remove all internal libc usage of: creat(), pause(), sleep(), system(),
tcdrain(), wait(), and waitpid().

Make thread cancellation fully POSIX-compliant.

Suggested by: deischen

Add three-tier symbol naming in support of POSIX thread cancellation
points. For library functions, the pattern is __sleep() <--
_libc_sleep() <-- sleep(). The arrows represent weak aliases. For
system calls, the pattern is _read() <-- _libc_read() <-- read().

$Id$ -> $FreeBSD$

Don't check for the unlikely case of useconds == 0 here. The kernel
checks it.

Fixed a style bug.

Back out part of OpenGroup specs about limiting max arg since it may break
compatibility.

Changes in spirit of OpenGroup Singe Unix specs:
1) Limit max allowed argument to 1000000
2) Change return type from void to int to indicate premature termination
(by signal)

Add $Id

Cleanup #includes

Remove old SIGALRM absorbing back-compat code. It wasn't working at all
for the entire time that it was there, so obviously nothing needs it
anymore.

Note, unix98/single-unix spec v2 says that usleep() returns an int rather
than a void, to indicate whether the entire time period elapsed (0) or an
error (eg: signal handler) interrupted it (returns -1, errno = EINTR)
It is probably useful to make this change but I'll test it locally first
to see if this will break userland programs [much]...

Reviewed by: ache, bde

Oops, fix logic for previous commit

Break loop if error != EINTR occurse or it can take forever with
time_remaining unchanged

Handle syscalls error return slightly better

Back out my installation of SIGALRM handler even if it is blocked
and return to previous Peter's variant.
POSIX says that this place is implementation defined and old variant allows
application block SIGALRM and sleep and not be killed by external SIGALRMs.
BTW, GNU sleep f.e. sleeps forever in blocked SIGALRM :-)

1) Make usleep() terminateable by alarm (or ualarm) as supposed
historically
2) Fix end of time loop condition: && -> ||

Make sleep() and usleep() "eat" any stray SIGALRM signals during the
lifetime of the call, just like the old implementation did. Previously,
we were only eating them if the application did not call sleep()/usleep()
with SIGALRM masked.

Submitted by: ache

Re-activate the nanosleep style using code, but with the signal handling
semantics of the old sleep for compatability with a few decades of expected
side effects. Apache breaks if we just use nanosleep() for some reason,
here we use a new signanosleep() syscall which is kinda like a hybrid of
sigsuspend and nanosleep..

Reviewed by: ache (and tested on his apache that was failing when
sleep used plain nanosleep)

Update the sleep(3)/usleep(3) code to use signanosleep(2) if compiled with
-DUSE_NANOSLEEP. Also, seperate the code for _THREAD_SAFE so that it uses
the simpler threaded nanosleep() call in libc_r.. We don't go to the same
extremes for emulating traditional sleep semantics (ie: eating any SIGALRM
that might happen) which things like apache seem to depend on.

Update the nanosleep versions to set a SIGALRM handler while sleeping.
This appears to appease Apache, although depending on having sleep(3)
changing the SIGALRM handler is a bit bogus.

if nanosleep returns too early, loop. usleep() does not have a return
value, it appears as though the semantics of usleep are that it doesn't
return early. (only in the nanosleep code - the setitimer code does this
already)

Allow conditional use (add -DUSE_NANOSLEEP) to CFLAGS of nanosleep() for
the backend of sleep(3) and usleep(3). It's off by default until the
problem is fixed.

Fix typo from previous commit (tsvsec --> tv_sec).

ts_sec -> tv_sec
ts_nsec -> tv_nsec

Reviewed by: julian and (hsu?)
Submitted by: John Birrel(L?)

changes for threadsafe operations

Minor cleanup, mostly unused vars and missing #includes.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Lib Sources