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Diffstat (limited to 'pthreads/signal.c')
| -rw-r--r-- | pthreads/signal.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/pthreads/signal.c b/pthreads/signal.c new file mode 100644 index 000000000..8f56c48b5 --- /dev/null +++ b/pthreads/signal.c @@ -0,0 +1,179 @@ +/* + * signal.c + * + * Description: + * Thread-aware signal functions. + * + * -------------------------------------------------------------------------- + * + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright(C) 1998 John E. Bossom + * Copyright(C) 1999,2005 Pthreads-win32 contributors + * + * Contact Email: rpj@callisto.canberra.edu.au + * + * The current list of contributors is contained + * in the file CONTRIBUTORS included with the source + * code distribution. The list can also be seen at the + * following World Wide Web location: + * http://sources.redhat.com/pthreads-win32/contributors.html + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +/* + * Possible future strategy for implementing pthread_kill() + * ======================================================== + * + * Win32 does not implement signals. + * Signals are simply software interrupts. + * pthread_kill() asks the system to deliver a specified + * signal (interrupt) to a specified thread in the same + * process. + * Signals are always asynchronous (no deferred signals). + * Pthread-win32 has an async cancelation mechanism. + * A similar system can be written to deliver signals + * within the same process (on ix86 processors at least). + * + * Each thread maintains information about which + * signals it will respond to. Handler routines + * are set on a per-process basis - not per-thread. + * When signalled, a thread will check it's sigmask + * and, if the signal is not being ignored, call the + * handler routine associated with the signal. The + * thread must then (except for some signals) return to + * the point where it was interrupted. + * + * Ideally the system itself would check the target thread's + * mask before possibly needlessly bothering the thread + * itself. This could be done by pthread_kill(), that is, + * in the signaling thread since it has access to + * all pthread_t structures. It could also retrieve + * the handler routine address to minimise the target + * threads response overhead. This may also simplify + * serialisation of the access to the per-thread signal + * structures. + * + * pthread_kill() eventually calls a routine similar to + * ptw32_cancel_thread() which manipulates the target + * threads processor context to cause the thread to + * run the handler launcher routine. pthread_kill() must + * save the target threads current context so that the + * handler launcher routine can restore the context after + * the signal handler has returned. Some handlers will not + * return, eg. the default SIGKILL handler may simply + * call pthread_exit(). + * + * The current context is saved in the target threads + * pthread_t structure. + */ + +#include "pthread.h" +#include "implement.h" + +#if HAVE_SIGSET_T + +static void +ptw32_signal_thread () +{ +} + +static void +ptw32_signal_callhandler () +{ +} + +int +pthread_sigmask (int how, sigset_t const *set, sigset_t * oset) +{ + pthread_t thread = pthread_self (); + + if (thread.p == NULL) + { + return ENOENT; + } + + /* Validate the `how' argument. */ + if (set != NULL) + { + switch (how) + { + case SIG_BLOCK: + break; + case SIG_UNBLOCK: + break; + case SIG_SETMASK: + break; + default: + /* Invalid `how' argument. */ + return EINVAL; + } + } + + /* Copy the old mask before modifying it. */ + if (oset != NULL) + { + memcpy (oset, &(thread.p->sigmask), sizeof (sigset_t)); + } + + if (set != NULL) + { + unsigned int i; + + /* FIXME: this code assumes that sigmask is an even multiple of + the size of a long integer. */ + + unsigned long *src = (unsigned long const *) set; + unsigned long *dest = (unsigned long *) &(thread.p->sigmask); + + switch (how) + { + case SIG_BLOCK: + for (i = 0; i < (sizeof (sigset_t) / sizeof (unsigned long)); i++) + { + /* OR the bit field longword-wise. */ + *dest++ |= *src++; + } + break; + case SIG_UNBLOCK: + for (i = 0; i < (sizeof (sigset_t) / sizeof (unsigned long)); i++) + { + /* XOR the bitfield longword-wise. */ + *dest++ ^= *src++; + } + case SIG_SETMASK: + /* Replace the whole sigmask. */ + memcpy (&(thread.p->sigmask), set, sizeof (sigset_t)); + break; + } + } + + return 0; +} + +int +sigwait (const sigset_t * set, int *sig) +{ + /* This routine is a cancellation point */ + pthread_test_cancel(); +} + +int +sigaction (int signum, const struct sigaction *act, struct sigaction *oldact) +{ +} + +#endif /* HAVE_SIGSET_T */ |