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* libthr: In the atfork handlers for signals, do not skip the last signal.jilles2012-03-261-3/+3
| | | | | | | | _SIG_MAXSIG works a bit unexpectedly: signals 1 till _SIG_MAXSIG are valid, both bounds inclusive. Reviewed by: davidxu MFC after: 1 week
* Use getcontextx(3) internal API instead of getcontext(2) to providekib2012-01-211-4/+13
| | | | | | | | | | | | | the signal handlers with the context information in the deferrred case. Only enable the use of getcontextx(3) in the deferred signal delivery code on amd64 and i386. Sparc64 seems to have some undetermined issues with interaction of alloca(3) and signal delivery. Tested by: flo (who also provided sparc64 harware access for me), pho Discussed with: marius MFC after: 1 month
* Fix a typo.davidxu2011-01-111-1/+1
| | | | Submitted by: avg
* Return previous sigaction correctly.davidxu2010-10-291-1/+4
| | | | Submitted by: avg
* Remove local variable 'first', instead check signal number in memory,davidxu2010-10-291-4/+1
| | | | | because the variable can be in register, second checking the variable may still return true, however this is unexpected.
* If we are at cancellation point, always work as deferred mode despitedavidxu2010-09-211-34/+32
| | | | | | whether asynchronous mode is turned on or not, this always gives us a chance to decide whether thread should be canceled or not in cancellation points.
* Because atfork lock is held while forking, a thread cancellation triggereddavidxu2010-09-191-5/+1
| | | | by atfork handler is unsafe, use intenal flag no_cancel to disable it.
* Because POSIX does not allow EINTR to be returned from sigwait(),davidxu2010-09-101-6/+8
| | | | | | | | add a wrapper for it in libc and rework the code in libthr, the system call still can return EINTR, we keep this feature. Discussed on: thread Reviewed by: jilles
* Fix off-by-one error in function _thr_sigact_unload, also disable thedavidxu2010-09-061-3/+5
| | | | | function, it seems some gnome application tends to crash if we unregister sigaction automatically.
* Remove incorrect comments, also make sure signal isdavidxu2010-09-011-5/+4
| | | | disabled when unregistering sigaction.
* Add signal handler wrapper, the reason to add it becauses there aredavidxu2010-09-011-99/+419
| | | | | | | | | | | | | | | | | | | | | | | 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.
* Add wrapper for setcontext() and swapcontext(), the wrappersdavidxu2010-08-241-14/+45
| | | | unblock SIGCANCEL which is needed by thread cancellation.
* Reduce redundant code.davidxu2010-08-201-76/+21
| | | | Submitted by: kib
* In current implementation, thread cancellation is done in signal handler,davidxu2010-08-201-14/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | which does not know what is the state of interrupted system call, for example, open() system call opened a file and the thread is still cancelled, result is descriptor leak, there are other problems which can cause resource leak or undeterminable side effect when a thread is cancelled. However, this is no longer true in new implementation. In defering mode, a thread is canceled if cancellation request is pending and later the thread enters a cancellation point, otherwise, a later pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and causes target thread to abort system call, userland code in libthr then checks cancellation state, and cancels the thread if needed. For example, the cancellation point open(), the thread may be canceled at start, but later, if it opened a file descriptor, it is not canceled, this avoids file handle leak. Another example is read(), a thread may be canceled at start of the function, but later, if it read some bytes from a socket, the thread is not canceled, the caller then can decide if it should still enable cancelling or disable it and continue reading data until it thinks it has read all bytes of a packet, and keeps a protocol stream in health state, if user ignores partly reading of a packet without disabling cancellation, then second iteration of read loop cause the thread to be cancelled. An exception is that the close() cancellation point always closes a file handle despite whether the thread is cancelled or not. The old mechanism is still kept, for a functions which is not so easily to fix a cancellation problem, the rough mechanism is used. Reviewed by: kib@
* Use _SIG_VALID instead of expanded form of the macro.kib2010-07-121-1/+1
| | | | | Submitted by: Garrett Cooper <yanegomi gmail com> MFC after: 1 week
* Use UMTX_OP_WAIT_UINT_PRIVATE and UMTX_OP_WAKE_PRIVATE to savedavidxu2008-04-291-3/+3
| | | | time in kernel(avoid VM lookup).
* - Copy signal mask out before THR_UNLOCK(), because THR_UNLOCK() may calldavidxu2008-03-181-0/+3
| | | | | | | | _thr_suspend_check() which messes sigmask saved in thread structure. - Don't suspend a thread has force_exit set. - In pthread_exit(), if there is a suspension flag set, wake up waiting- thread after setting PS_DEAD, this causes waiting-thread to break loop in suspend_common().
* Increase and decrease in_sigcancel_handler accordingly to avoid possibledavidxu2008-03-051-2/+2
| | | | error caused by nested SIGCANCEL stack, it is a bit complex.
* If a new thread is created, it inherits current thread's signal masks,davidxu2008-03-041-0/+2
| | | | | | | | however if current thread is executing cancellation handler, signal SIGCANCEL may have already been blocked, this is unexpected, unblock the signal in new thread if this happens. MFC after: 1 week
* Add some function prototypes.davidxu2007-11-211-0/+5
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* Remove umtx_t definition, use type long directly, add wrapper functiondavidxu2007-11-211-1/+2
| | | | | _thr_umtx_wait_uint() for umtx operation UMTX_OP_WAIT_UINT, use the function in semaphore operations, this fixed compiler warnings.
* test cancel_pending to save a thr_wake call in some specical cases.davidxu2006-12-061-1/+1
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* Use kernel provided userspace condition variable to implement pthreaddavidxu2006-12-041-0/+2
| | | | condition variable.
* Eliminate atomic operations in thread cancellation functions, it shoulddavidxu2006-11-241-18/+11
| | | | reduce overheads of cancellation points.
* Replace internal usage of struct umtx with umutex which can supportsdavidxu2006-09-061-4/+4
| | | | real-time if we want, no functionality is changed.
* 1. Don't override underscore version of aio_suspend(), system(),davidxu2006-07-251-1/+107
| | | | | | | | | | wait(), waitpid() and usleep(), they are internal versions and should not be cancellation points. 2. Make wait3() as a cancellation point. 3. Move raise() and pause() into file thr_sig.c. 4. Add functions _sigsuspend, _sigwait, _sigtimedwait and _sigwaitinfo, remove SIGCANCEL bit in wait-set for those functions, the signal is used internally to implement thread cancellation.
* WARNS level 4 cleanup.davidxu2006-04-041-1/+9
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* Check cancellation state carefully to see we really need to calldavidxu2006-03-261-2/+5
| | | | _pthread_testcancel(). Preserve errno in _thr_suspend_check().
* Add locking support for rtld.davidxu2006-03-251-2/+3
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* Refine thread suspension code, now thread suspension is a blockabledavidxu2006-01-051-17/+50
| | | | | | | operation, the caller is blocked util target threads are really suspended, also avoid suspending a thread when it is holding a critical lock. Fix a bug in _thr_ref_delete which tests a never set flag.
* Update copyright.davidxu2005-12-171-19/+13
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* Import my recent 1:1 threading working. some features improved includes:davidxu2005-04-021-48/+198
| | | | | | | | | | | | | | | | 1. fast simple type mutex. 2. __thread tls works. 3. asynchronous cancellation works ( using signal ). 4. thread synchronization is fully based on umtx, mainly, condition variable and other synchronization objects were rewritten by using umtx directly. those objects can be shared between processes via shared memory, it has to change ABI which does not happen yet. 5. default stack size is increased to 1M on 32 bits platform, 2M for 64 bits platform. As the result, some mysql super-smack benchmarks show performance is improved massivly. Okayed by: jeff, mtm, rwatson, scottl
* Make libthr async-signal-safe without costly signal masking. The guidlines Imtm2004-05-201-77/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
* Make the minimum implementation of pthread_kill conform to themtm2004-03-291-0/+13
| | | | | | | functionality spelled out in SUSv3. o Signal of 0 means do everything except send the signal o Check that the signal is not invalid o Check that the target thread is not dead/invalid
* o Since we're not using signals for thread synchronization anymore,mtm2004-03-271-30/+0
| | | | | | | | sigprocmask no longer needs to be wrapped. o raise(3) is applied to the calling thread in a threaded program. o In the sigaction wrapper reference the correct structure. o Don't treat SIGTHR especially anymore (infact it won't exist in a little while).
* Implement PThreads barriers and barrier attributes.mtm2004-02-191-0/+7
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* Don't wake up the thread after the signal handlermtm2004-02-191-1/+1
| | | | | | | | has been executed. On return from the signal handler the call will either be restarted or EINTR will be returned, but it will not go back to its previous state. So, it is sufficient to simply change the state to 'running' without actually trying to wake up the thread.
* Fix the wrapper function around signals so that a signal handlingmtm2003-12-091-24/+44
| | | | | thread on one of the mutex or condition variable queues is removed from those queues before the real signal handler is called.
* Make WARNS2 clean. The fixes mostly included:mtm2003-05-231-2/+2
| | | | | | | | o removed unused variables o explicit inclusion of header files o prototypes for externally defined functions Approved by: re/blanket libthr
* msg2mtm2003-05-121-7/+7
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* o Correct a debug message that refered to the wrong functionmtm2003-05-061-22/+19
| | | | | | | o Remove an unncecesary if clause Approved by: markm (mentor)(implicit) Reviewd by: jeff
* - Define curthread as _get_curthread() and remove all direct calls tojeff2003-04-021-1/+0
| | | | | | | _get_curthread(). This is similar to the kernel's curthread. Doing this saves stack overhead and is more convenient to the programmer. - Pass the pointer to the newly created thread to _thread_init(). - Remove _get_curthread_slow().
* - Add libthr but don't hook it up to the regular build yet. This is anjeff2003-04-011-0/+166
adaptation of libc_r for the thr system call interface. This is beta quality code.
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