src/lib/libthr/thread/thr_create.c, branch releng/12.4

POSIX compliance improvements in the pthread(3) functions.

2018-08-18T01:05:38Z

This basically adds makes use of the C99 restrict keyword, and also adds some 'const's to four threading functions: pthread_mutexattr_gettype(), pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), and pthread_mutex_getprioceiling. The changes are in accordance to POSIX/SUSv4-2018. Hinted by: DragonFlyBSD Relnotes: yes MFC after: 1 month Differential Revision: D16722

lib: further adoption of SPDX licensing ID tags.

2017-11-26T02:00:33Z

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.

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

2016-04-08T11:15:26Z

Implement process-shared locks support for libthr.so.3, without

2016-02-28T17:52:33Z

breaking the ABI. Special value is stored in the lock pointer to indicate shared lock, and offline page in the shared memory is allocated to store the actual lock. Reviewed by: vangyzen (previous version) Discussed with: deischen, emaste, jhb, rwatson, Martin Simmons Tested by: pho Sponsored by: The FreeBSD Foundation

cosmetic: whitespaces-tab before EOL

2015-07-08T16:35:24Z

Obtained from: cpi-llvm project

Fix known issues which blow up the process after dlopen("libthr.so")

2015-01-03T18:38:46Z

(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

Implement the __pthread_map_stacks_exec() for libthr.

2011-01-09T12:38:40Z

Stack creation code is changed to call _rtld_get_stack_prot() to get the stack protection right. There is a race where thread is created during dlopen() of dso that requires executable stacks. Then, _rtld_get_stack_prot() may return PROT_READ | PROT_WRITE, but thread is still not linked into the thread list. In this case, the callback misses the thread stack, and rechecks the required protection afterward. Reviewed by: davidxu

add code to support stack unwinding when thread exits. note that only

2010-09-15T02:56:32Z

defer-mode cancellation works, asynchrnous mode does not work because it lacks of libuwind's support. stack unwinding is not enabled unless LIBTHR_UNWIND_STACK is defined in Makefile.

Convert thread list lock from mutex to rwlock.

2010-09-13T07:03:01Z

Add signal handler wrapper, the reason to add it becauses there are

2010-09-01T02:18:33Z

some cases we want to improve: 1) if a thread signal got a signal while in cancellation point, it is possible the TDP_WAKEUP may be eaten by signal handler if the handler called some interruptibly system calls. 2) In signal handler, we want to disable cancellation. 3) When thread holding some low level locks, it is better to disable signal, those code need not to worry reentrancy, sigprocmask system call is avoided because it is a bit expensive. The signal handler wrapper works in this way: 1) libthr installs its signal handler if user code invokes sigaction to install its handler, the user handler is recorded in internal array. 2) when a signal is delivered, libthr's signal handler is invoke, libthr checks if thread holds some low level lock or is in critical region, if it is true, the signal is buffered, and all signals are masked, once the thread leaves critical region, correct signal mask is restored and buffered signal is processed. 3) before user signal handler is invoked, cancellation is temporarily disabled, after user signal handler is returned, cancellation state is restored, and pending cancellation is rescheduled.