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/*
* signal.c
*
* Description:
* Thread-aware signal functions.
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright (C) 1998
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA
*/
/*
* 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 == 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->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->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->sigmask), set, sizeof(sigset_t));
break;
}
}
return 0;
}
int pthread_kill(pthread_t thread,
int signo)
{
}
int sigwait(const sigset_t *set,
int *sig)
{
}
int sigaction(int signum,
const struct sigaction *act,
struct sigaction *oldact)
{
}
#endif /* HAVE_SIGSET_T */

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