openbsd/src/lib/libc/include, branch OPENBSD_7_8_BASE

replace the flockfile backend with a per FILE recursive mutex.

2025-08-04T01:44:33+00:00

the flockfile implementation in thread/rthread_file.c used an external lock, and associated it with the relevant FILE * as needed. this isn't great for a lot of reasons, complexity being the big one, but the straw that broke the camels back is that it uses a single spinlock to coordinate all of this, which in turn generates a lot of sched_yield syscalls. this avoids all the code complexity and the spinlock by just embedding a small __rctmx in every FILE. tested by and ok tb@ jca@ ok claudio@

This thread-aware profiling support diff comes from Yuichiro NAITO.

2025-07-16T16:22:58+00:00

At runtime, profiling data is stored per-thread. Upon termination, the per-thread profiling data pools are merged into a into a single record, which is then written out (using the new kernel-assisted system). I think the original gmon merging parts may have come from or been inspired by someone at NetBSD. This has been delayed because there were concerns about adding a TLS object which would require other library cranks, so this rides all the major cranks today. ok kettenis tb claudio sthen etc etc etc

add libc specific cmtx and rcmtx locks for internal use.

2025-07-12T23:59:44+00:00

__cmtx provides mutual exclusion using futex(2) and cas on archs that support it, or _spinlocks on the rest. __rcmtx is a recursive mutex built on top of __cmtx, so it inherits the use of futex and cas/spinlock from __cmtx. until now the options we had for locking between threads in libc were spinlocks or pthread mutexes. spinlocks use sched_yield to relax if they have to spin on a contended lock, which we are trying to minimise the use of as much as possible. pthread_mutex is relatively large in memory and offers a lot of complicated features which are unecessary for most of libc. the non cas/futex version of pthread_mutexes currently relies on __thrsleep and __thrwakeup, which we also want to deprecate. having a small futex based lock available everywhere will help us move away from overuse of spinlocks, and deprecate __thrsleep and __thrwakeup. ok kettenis@ jca@ provided his eyes too.

Use struct __sFILE instead of FILE in thread locking callback

2024-08-18T02:25:51+00:00

declarations to reduce pollution. Declare __isthreaded in thread_private.h where it's really needed. ok deraadt@

Enable ISO C11 APIs when building libc, even with an older compiler.

2023-10-29T14:26:13+00:00

Otherwise, the prototypes for timespec_get() and aligned_alloc() are not visible. OK guenther@

Update to reflect changes over the last six years

2021-12-25T01:13:44+00:00

Fix two issues related to thread private data in asr.

2021-01-06T19:54:17+00:00

- setting up asr in single thread mode and then starting threads using asr would lead to multiple threads sharing the same resolver. - destruction of a thread that has been using asr would leak data. Problem originally reported by Alexey Sokolov and Uli Schlachter. ok kettenis@

gcc3, like clang and unlike our gcc4, doesn't support redirecting builtins

2019-11-25T22:57:28+00:00

like mem{set,cpy,move} or __stack_smash_handler using asm() renaming. So treat gcc3 like clang and mark such functions as protected instead. ok ayoma@

Complete the ld.so boot cleanup: move most libc initialization from

2019-06-02T01:03:01+00:00

_csu_finish() to _libc_preinit(), which is an .init_array function in shared libc (and mark it INITFIRST) or a .preinit_array function in static libc, grabbing the _dl_cb callback there from ld.so. Then in _csu_finish(), invoke the dl_clean_boot() callback to free ld.so's startup bits before main() gets control. Other cleanups this permits: - move various startup structures into .data.rel.ro - the dl* stubs in libc can be strong and call the callbacks provided via _dl_cb - no longer need to conditionalize dlctl() calls on presence of _DYNAMIC original concept and full diff ok kettenis@ ok deraadt@

Move 'how this works' details from namespace.h to DETAILS

2019-05-13T20:00:32+00:00