pthread_setcancelstate(3): make it async-signal-safe

by setting new cancel state and reading old cancel state from the
curthread structure atomic.

Note that this does not play well with async cance

pthread_setcancelstate(3): make it async-signal-safe

by setting new cancel state and reading old cancel state from the
curthread structure atomic.

Note that this does not play well with async cancellation, since if
cancellation is enabled from a signal handler and cancellation request
is pending, the thread is cancelled immediately, calling user-defined
destructors, which all must be async-signal-safe (but this is a general
requirement for async cancellation anyway).

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D48200

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thr_cancel.c: use testcancel() instead of manually expanding it

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D48200

thr_cancel.c: style

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D48200

libthr: remove explicit sys/cdefs.h includes

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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Merge ^/head r357855 through r357920.

Return success, instead of ESRCH, from pthread_cancel(3) applied to the
exited but not yet joined thread.

Before, if the thread exited but was not yet joined, we returned
ESRCH.

According to IEEE S

Return success, instead of ESRCH, from pthread_cancel(3) applied to the
exited but not yet joined thread.

Before, if the thread exited but was not yet joined, we returned
ESRCH.

According to IEEE Std 1003.1™-2017 recommendation in the
description of pthread_cancel(3):
If an implementation detects use of a thread ID after the end of its
lifetime, it is recommended that the function should fail and report
an [ESRCH] error.
So it seems desirable to not return ESRCH until the lifetime of the
thread ID ends. According to the section 2.9.2 Thread IDs,
The lifetime of a thread ID ends after the thread terminates if it
was created with the detachstate attribute set to
PTHREAD_CREATE_DETACHED or if pthread_detach() or pthread_join()
has been called for that thread.
In other words, lifetime for thread ID of exited but not yet joined thread
did not ended yet.

Prompted by: cperciva
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Merge ^/head r351317 through r351731.

Fix _pthread_cancel_enter() and _pthread_cancel_leave() jmptable entries.

PR: 240022
Reported by: Andrew Gierth <andrew@tao11.riddles.org.uk>
Sponsored by: The FreeBSD Foundation
MFC after: 3 days

Avoid conflicts with libc symbols in libthr jump table.

In some corner cases of static linking and unexpected libraries order
on the linker command line, libc symbol might preempt the same libthr
sy

Avoid conflicts with libc symbols in libthr jump table.

In some corner cases of static linking and unexpected libraries order
on the linker command line, libc symbol might preempt the same libthr
symbol, in which case libthr jump table points back to libc causing
either infinite recursion or loop. Handle all of such symbols by
using private libthr names for them, ensuring that the right pointers
are installed into the table.

In collaboration with: arichardson
PR: 239475
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21088

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Ensure thread library is initialized in pthread_testcancel().

Call _thr_check_init() before reading curthread in pthread_testcancel().

If a constructor in a library creates a semaphore via sem_init

Ensure thread library is initialized in pthread_testcancel().

Call _thr_check_init() before reading curthread in pthread_testcancel().

If a constructor in a library creates a semaphore via sem_init() and
then waits for it via sem_wait(), the program can core dump in
_pthread_testcancel() called from sem_wait(). This is because the
semaphore implementation lives in libc, so the library's constructors
can be run before libthr's constructors.

Reported by: arichardson
Reviewed by: kib
Obtained from: CheriBSD
MFC after: 1 week
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D14786

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lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
pr

lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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MFH

Sponsored by: The FreeBSD Foundation

Use __FBSDID() for .c files from lib/libthr/thread.

Sponsored by: The FreeBSD Foundation

Merge from head

IFC @ r254014

IFC @253398

IFC @ r252047

Merge fresh head.

The SUSv4tc1 requires that pthread_setcancelstate() shall be not a
cancellation point. When enabling the cancellation, only process the
pending cancellation for asynchronous mode.

Reported and revi

The SUSv4tc1 requires that pthread_setcancelstate() shall be not a
cancellation point. When enabling the cancellation, only process the
pending cancellation for asynchronous mode.

Reported and reviewed by: Kohji Okuno <okuno.kohji@jp.panasonic.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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To support stack unwinding for cancellation points, add -fexceptions flag
for them, two functions _pthread_cancel_enter and _pthread_cancel_leave
are added to let thread enter and leave a cancellatio

To support stack unwinding for cancellation points, add -fexceptions flag
for them, two functions _pthread_cancel_enter and _pthread_cancel_leave
are added to let thread enter and leave a cancellation point, it also
makes it possible that other functions can be cancellation points in
libraries without having to be rewritten in libthr.

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inline testcancel() into thr_cancel_leave(), because cancel_pending is
almost false, this makes a slight better branch predicting.

In most cases, cancel_point and cancel_async needn't be checked again,
because cancellation is almostly checked at cancellation points.

Convert thread list lock from mutex to rwlock.