760 lines
20 KiB
C
760 lines
20 KiB
C
/*
|
|
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by John Birrell.
|
|
* 4. Neither the name of the author nor the names of any co-contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
#include <sys/param.h>
|
|
#include <sys/types.h>
|
|
#include <sys/signalvar.h>
|
|
#include <signal.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <setjmp.h>
|
|
#include <errno.h>
|
|
#ifdef _THREAD_SAFE
|
|
#include <pthread.h>
|
|
#include "pthread_private.h"
|
|
|
|
/* Prototypes: */
|
|
static void thread_sig_check_state(pthread_t pthread, int sig);
|
|
static void thread_sig_finish_longjmp(void *arg);
|
|
static void handle_state_change(pthread_t pthread);
|
|
|
|
|
|
/* Static variables: */
|
|
static spinlock_t signal_lock = _SPINLOCK_INITIALIZER;
|
|
static unsigned int pending_sigs[NSIG];
|
|
static unsigned int handled_sigs[NSIG];
|
|
static int volatile check_pending = 0;
|
|
static int volatile check_waiting = 0;
|
|
|
|
/* Initialize signal handling facility: */
|
|
void
|
|
_thread_sig_init(void)
|
|
{
|
|
int i;
|
|
|
|
/* Clear pending and handled signal counts: */
|
|
for (i = 1; i < NSIG; i++) {
|
|
pending_sigs[i - 1] = 0;
|
|
handled_sigs[i - 1] = 0;
|
|
}
|
|
|
|
/* Clear the lock: */
|
|
signal_lock.access_lock = 0;
|
|
|
|
/* Clear the process pending signals: */
|
|
sigemptyset(&_process_sigpending);
|
|
}
|
|
|
|
void
|
|
_thread_sig_handler(int sig, int code, ucontext_t * scp)
|
|
{
|
|
pthread_t pthread, pthread_next;
|
|
int i;
|
|
char c;
|
|
|
|
/* Check if an interval timer signal: */
|
|
if (sig == _SCHED_SIGNAL) {
|
|
if (_thread_kern_in_sched != 0) {
|
|
/*
|
|
* The scheduler is already running; ignore this
|
|
* signal.
|
|
*/
|
|
}
|
|
/*
|
|
* Check if the scheduler interrupt has come when
|
|
* the currently running thread has deferred thread
|
|
* signals.
|
|
*/
|
|
else if (_thread_run->sig_defer_count > 0)
|
|
_thread_run->yield_on_sig_undefer = 1;
|
|
|
|
else {
|
|
/*
|
|
* Schedule the next thread. This function is not
|
|
* expected to return because it will do a longjmp
|
|
* instead.
|
|
*/
|
|
_thread_kern_sched(scp);
|
|
|
|
/*
|
|
* This point should not be reached, so abort the
|
|
* process:
|
|
*/
|
|
PANIC("Returned to signal function from scheduler");
|
|
}
|
|
}
|
|
/*
|
|
* Check if the kernel has been interrupted while the scheduler
|
|
* is accessing the scheduling queues or if there is a currently
|
|
* running thread that has deferred signals.
|
|
*/
|
|
else if ((_queue_signals != 0) || ((_thread_kern_in_sched == 0) &&
|
|
(_thread_run->sig_defer_count > 0))) {
|
|
/* Cast the signal number to a character variable: */
|
|
c = sig;
|
|
|
|
/*
|
|
* Write the signal number to the kernel pipe so that it will
|
|
* be ready to read when this signal handler returns.
|
|
*/
|
|
_thread_sys_write(_thread_kern_pipe[1], &c, 1);
|
|
|
|
/* Indicate that there are queued signals in the pipe. */
|
|
_sigq_check_reqd = 1;
|
|
} else {
|
|
if (_atomic_lock(&signal_lock.access_lock)) {
|
|
/* There is another signal handler running: */
|
|
pending_sigs[sig - 1]++;
|
|
check_pending = 1;
|
|
}
|
|
else {
|
|
/* It's safe to handle the signal now. */
|
|
pthread = _thread_sig_handle(sig, scp);
|
|
|
|
/* Reset the pending and handled count back to 0: */
|
|
pending_sigs[sig - 1] = 0;
|
|
handled_sigs[sig - 1] = 0;
|
|
|
|
if (pthread == NULL)
|
|
signal_lock.access_lock = 0;
|
|
else {
|
|
sigaddset(&pthread->sigmask, sig);
|
|
|
|
/*
|
|
* Make sure not to deliver the same signal to
|
|
* the thread twice. sigpend is potentially
|
|
* modified by the call chain
|
|
* _thread_sig_handle() -->
|
|
* thread_sig_check_state(), which can happen
|
|
* just above.
|
|
*/
|
|
if (sigismember(&pthread->sigpend, sig))
|
|
sigdelset(&pthread->sigpend, sig);
|
|
|
|
signal_lock.access_lock = 0;
|
|
_thread_sig_deliver(pthread, sig);
|
|
sigdelset(&pthread->sigmask, sig);
|
|
}
|
|
}
|
|
|
|
/* Enter a loop to process pending signals: */
|
|
while ((check_pending != 0) &&
|
|
(_atomic_lock(&signal_lock.access_lock) == 0)) {
|
|
check_pending = 0;
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (pending_sigs[i - 1] > handled_sigs[i - 1]) {
|
|
pending_sigs[i - 1] = handled_sigs[i - 1];
|
|
pthread = _thread_sig_handle(i, scp);
|
|
if (pthread != NULL) {
|
|
sigaddset(&pthread->sigmask, i);
|
|
/* Save the old state: */
|
|
pthread->oldstate = pthread->state;
|
|
signal_lock.access_lock = 0;
|
|
_thread_sig_deliver(pthread, i);
|
|
sigdelset(&pthread->sigmask, i);
|
|
if (_atomic_lock(&signal_lock.access_lock)) {
|
|
check_pending = 1;
|
|
/*
|
|
* Have the lock holder take care
|
|
* of any state changes:
|
|
*/
|
|
if (pthread->state != pthread->oldstate)
|
|
check_waiting = 1;
|
|
return;
|
|
}
|
|
if (pthread->state != pthread->oldstate)
|
|
handle_state_change(pthread);
|
|
}
|
|
}
|
|
}
|
|
while (check_waiting != 0) {
|
|
check_waiting = 0;
|
|
/*
|
|
* Enter a loop to wake up all threads waiting
|
|
* for a process to complete:
|
|
*/
|
|
for (pthread = TAILQ_FIRST(&_waitingq);
|
|
pthread != NULL; pthread = pthread_next) {
|
|
pthread_next = TAILQ_NEXT(pthread, pqe);
|
|
if (pthread->state == PS_RUNNING)
|
|
handle_state_change(pthread);
|
|
}
|
|
}
|
|
/* Release the lock: */
|
|
signal_lock.access_lock = 0;
|
|
}
|
|
|
|
/*
|
|
* Check to see if the current thread performed a
|
|
* [sig|_]longjmp() out of a signal handler.
|
|
*/
|
|
if ((_thread_run->jmpflags & (JMPFLAGS_LONGJMP |
|
|
JMPFLAGS__LONGJMP)) != 0) {
|
|
_thread_run->jmpflags = JMPFLAGS_NONE;
|
|
__longjmp(_thread_run->nested_jmp.jmp,
|
|
_thread_run->longjmp_val);
|
|
} else if ((_thread_run->jmpflags & JMPFLAGS_SIGLONGJMP) != 0) {
|
|
_thread_run->jmpflags = JMPFLAGS_NONE;
|
|
__siglongjmp(_thread_run->nested_jmp.sigjmp,
|
|
_thread_run->longjmp_val);
|
|
}
|
|
}
|
|
}
|
|
|
|
pthread_t
|
|
_thread_sig_handle(int sig, ucontext_t * scp)
|
|
{
|
|
int i, handler_installed;
|
|
pthread_t pthread, pthread_next;
|
|
pthread_t suspended_thread, signaled_thread;
|
|
|
|
/* Check if the signal requires a dump of thread information: */
|
|
if (sig == SIGINFO)
|
|
/* Dump thread information to file: */
|
|
_thread_dump_info();
|
|
|
|
/* Check if an interval timer signal: */
|
|
else if (sig == _SCHED_SIGNAL) {
|
|
/*
|
|
* This shouldn't ever occur (should this panic?).
|
|
*/
|
|
} else {
|
|
/* Check if a child has terminated: */
|
|
if (sig == SIGCHLD) {
|
|
/*
|
|
* Go through the file list and set all files
|
|
* to non-blocking again in case the child
|
|
* set some of them to block. Sigh.
|
|
*/
|
|
for (i = 0; i < _thread_dtablesize; i++) {
|
|
/* Check if this file is used: */
|
|
if (_thread_fd_table[i] != NULL) {
|
|
/*
|
|
* Set the file descriptor to
|
|
* non-blocking:
|
|
*/
|
|
_thread_sys_fcntl(i, F_SETFL,
|
|
_thread_fd_table[i]->flags |
|
|
O_NONBLOCK);
|
|
}
|
|
}
|
|
/*
|
|
* Enter a loop to wake up all threads waiting
|
|
* for a process to complete:
|
|
*/
|
|
for (pthread = TAILQ_FIRST(&_waitingq);
|
|
pthread != NULL; pthread = pthread_next) {
|
|
/*
|
|
* Grab the next thread before possibly
|
|
* destroying the link entry:
|
|
*/
|
|
pthread_next = TAILQ_NEXT(pthread, pqe);
|
|
|
|
/*
|
|
* If this thread is waiting for a child
|
|
* process to complete, wake it up:
|
|
*/
|
|
if (pthread->state == PS_WAIT_WAIT) {
|
|
/* Make the thread runnable: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* POSIX says that pending SIGCONT signals are
|
|
* discarded when one of these signals occurs.
|
|
*/
|
|
if (sig == SIGTSTP || sig == SIGTTIN || sig == SIGTTOU) {
|
|
/*
|
|
* Enter a loop to discard pending SIGCONT
|
|
* signals:
|
|
*/
|
|
TAILQ_FOREACH(pthread, &_thread_list, tle) {
|
|
sigdelset(&pthread->sigpend,SIGCONT);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enter a loop to look for threads that have the signal
|
|
* unmasked. POSIX specifies that a thread in a sigwait
|
|
* will get the signal over any other threads. Second
|
|
* preference will be threads in in a sigsuspend. If
|
|
* none of the above, then the signal is delivered to the
|
|
* first thread we find. Note that if a custom handler
|
|
* is not installed, the signal only affects threads in
|
|
* sigwait.
|
|
*/
|
|
suspended_thread = NULL;
|
|
signaled_thread = NULL;
|
|
if ((_thread_sigact[sig - 1].sa_handler == SIG_IGN) ||
|
|
(_thread_sigact[sig - 1].sa_handler == SIG_DFL))
|
|
handler_installed = 0;
|
|
else
|
|
handler_installed = 1;
|
|
|
|
for (pthread = TAILQ_FIRST(&_waitingq);
|
|
pthread != NULL; pthread = pthread_next) {
|
|
/*
|
|
* Grab the next thread before possibly destroying
|
|
* the link entry.
|
|
*/
|
|
pthread_next = TAILQ_NEXT(pthread, pqe);
|
|
|
|
if ((pthread->state == PS_SIGWAIT) &&
|
|
sigismember(pthread->data.sigwait, sig)) {
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
|
|
/*
|
|
* POSIX doesn't doesn't specify which thread
|
|
* will get the signal if there are multiple
|
|
* waiters, so we give it to the first thread
|
|
* we find.
|
|
*
|
|
* Do not attempt to deliver this signal
|
|
* to other threads.
|
|
*/
|
|
return (NULL);
|
|
}
|
|
else if ((handler_installed != 0) &&
|
|
!sigismember(&pthread->sigmask, sig)) {
|
|
if (pthread->state == PS_SIGSUSPEND) {
|
|
if (suspended_thread == NULL)
|
|
suspended_thread = pthread;
|
|
} else if (signaled_thread == NULL)
|
|
signaled_thread = pthread;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Only perform wakeups and signal delivery if there is a
|
|
* custom handler installed:
|
|
*/
|
|
if (handler_installed != 0) {
|
|
/*
|
|
* If we didn't find a thread in the waiting queue,
|
|
* check the all threads queue:
|
|
*/
|
|
if (suspended_thread == NULL &&
|
|
signaled_thread == NULL) {
|
|
/*
|
|
* Enter a loop to look for other threads
|
|
* capable of receiving the signal:
|
|
*/
|
|
TAILQ_FOREACH(pthread, &_thread_list, tle) {
|
|
if (!sigismember(&pthread->sigmask,
|
|
sig)) {
|
|
signaled_thread = pthread;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (suspended_thread == NULL &&
|
|
signaled_thread == NULL)
|
|
/*
|
|
* Add it to the set of signals pending
|
|
* on the process:
|
|
*/
|
|
sigaddset(&_process_sigpending, sig);
|
|
else {
|
|
/*
|
|
* We only deliver the signal to one thread;
|
|
* give preference to the suspended thread:
|
|
*/
|
|
if (suspended_thread != NULL)
|
|
pthread = suspended_thread;
|
|
else
|
|
pthread = signaled_thread;
|
|
|
|
/*
|
|
* Perform any state changes due to signal
|
|
* arrival:
|
|
*/
|
|
thread_sig_check_state(pthread, sig);
|
|
return (pthread);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Returns nothing. */
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
thread_sig_finish_longjmp(void *arg)
|
|
{
|
|
/*
|
|
* Check to see if the current thread performed a [_]longjmp() out of a
|
|
* signal handler.
|
|
*/
|
|
if ((_thread_run->jmpflags & (JMPFLAGS_LONGJMP | JMPFLAGS__LONGJMP))
|
|
!= 0) {
|
|
_thread_run->jmpflags = JMPFLAGS_NONE;
|
|
_thread_run->continuation = NULL;
|
|
__longjmp(_thread_run->nested_jmp.jmp,
|
|
_thread_run->longjmp_val);
|
|
}
|
|
/*
|
|
* Check to see if the current thread performed a siglongjmp
|
|
* out of a signal handler:
|
|
*/
|
|
else if ((_thread_run->jmpflags & JMPFLAGS_SIGLONGJMP) != 0) {
|
|
_thread_run->jmpflags = JMPFLAGS_NONE;
|
|
_thread_run->continuation = NULL;
|
|
__siglongjmp(_thread_run->nested_jmp.sigjmp,
|
|
_thread_run->longjmp_val);
|
|
}
|
|
}
|
|
|
|
static void
|
|
handle_state_change(pthread_t pthread)
|
|
{
|
|
/*
|
|
* We should only need to handle threads whose state was
|
|
* changed to running:
|
|
*/
|
|
if (pthread->state == PS_RUNNING) {
|
|
switch (pthread->oldstate) {
|
|
/*
|
|
* States which do not change when a signal is trapped:
|
|
*/
|
|
case PS_DEAD:
|
|
case PS_DEADLOCK:
|
|
case PS_RUNNING:
|
|
case PS_SIGTHREAD:
|
|
case PS_STATE_MAX:
|
|
break;
|
|
|
|
/*
|
|
* States which need to return to critical sections
|
|
* before they can switch contexts:
|
|
*/
|
|
case PS_COND_WAIT:
|
|
case PS_FDLR_WAIT:
|
|
case PS_FDLW_WAIT:
|
|
case PS_FILE_WAIT:
|
|
case PS_JOIN:
|
|
case PS_MUTEX_WAIT:
|
|
/* Indicate that the thread was interrupted: */
|
|
pthread->interrupted = 1;
|
|
/*
|
|
* Defer the [sig|_]longjmp until leaving the critical
|
|
* region:
|
|
*/
|
|
pthread->jmpflags |= JMPFLAGS_DEFERRED;
|
|
|
|
/* Set the continuation routine: */
|
|
pthread->continuation = thread_sig_finish_longjmp;
|
|
/* FALLTHROUGH */
|
|
case PS_FDR_WAIT:
|
|
case PS_FDW_WAIT:
|
|
case PS_POLL_WAIT:
|
|
case PS_SELECT_WAIT:
|
|
case PS_SIGSUSPEND:
|
|
case PS_SIGWAIT:
|
|
case PS_SLEEP_WAIT:
|
|
case PS_SPINBLOCK:
|
|
case PS_SUSPENDED:
|
|
case PS_WAIT_WAIT:
|
|
if ((pthread->flags & PTHREAD_FLAGS_IN_WAITQ) != 0) {
|
|
PTHREAD_WAITQ_REMOVE(pthread);
|
|
if (pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
|
|
PTHREAD_WORKQ_REMOVE(pthread);
|
|
}
|
|
break;
|
|
}
|
|
|
|
if ((pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) == 0)
|
|
PTHREAD_PRIOQ_INSERT_TAIL(pthread);
|
|
}
|
|
}
|
|
|
|
|
|
/* Perform thread specific actions in response to a signal: */
|
|
static void
|
|
thread_sig_check_state(pthread_t pthread, int sig)
|
|
{
|
|
/*
|
|
* Process according to thread state:
|
|
*/
|
|
switch (pthread->state) {
|
|
/*
|
|
* States which do not change when a signal is trapped:
|
|
*/
|
|
case PS_COND_WAIT:
|
|
case PS_DEAD:
|
|
case PS_DEADLOCK:
|
|
case PS_FILE_WAIT:
|
|
case PS_JOIN:
|
|
case PS_MUTEX_WAIT:
|
|
case PS_RUNNING:
|
|
case PS_STATE_MAX:
|
|
case PS_SIGTHREAD:
|
|
case PS_SPINBLOCK:
|
|
case PS_SUSPENDED:
|
|
/* Increment the pending signal count. */
|
|
sigaddset(&pthread->sigpend,sig);
|
|
break;
|
|
|
|
case PS_SIGWAIT:
|
|
/* Wake up the thread if the signal is blocked. */
|
|
if (sigismember(pthread->data.sigwait, sig)) {
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
} else
|
|
/* Increment the pending signal count. */
|
|
sigaddset(&pthread->sigpend,sig);
|
|
break;
|
|
|
|
/*
|
|
* The wait state is a special case due to the handling of
|
|
* SIGCHLD signals.
|
|
*/
|
|
case PS_WAIT_WAIT:
|
|
/*
|
|
* Check for signals other than the death of a child
|
|
* process:
|
|
*/
|
|
if (sig != SIGCHLD)
|
|
/* Flag the operation as interrupted: */
|
|
pthread->interrupted = 1;
|
|
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
break;
|
|
|
|
/*
|
|
* States that are interrupted by the occurrence of a signal
|
|
* other than the scheduling alarm:
|
|
*/
|
|
case PS_FDLR_WAIT:
|
|
case PS_FDLW_WAIT:
|
|
case PS_FDR_WAIT:
|
|
case PS_FDW_WAIT:
|
|
case PS_POLL_WAIT:
|
|
case PS_SLEEP_WAIT:
|
|
case PS_SELECT_WAIT:
|
|
if ((_thread_sigact[sig - 1].sa_flags & SA_RESTART) == 0) {
|
|
/* Flag the operation as interrupted: */
|
|
pthread->interrupted = 1;
|
|
|
|
if (pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
|
|
PTHREAD_WORKQ_REMOVE(pthread);
|
|
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
}
|
|
break;
|
|
|
|
case PS_SIGSUSPEND:
|
|
/*
|
|
* Only wake up the thread if there is a handler installed
|
|
* for the signal.
|
|
*/
|
|
if (_thread_sigact[sig - 1].sa_handler != SIG_DFL) {
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Send a signal to a specific thread (ala pthread_kill): */
|
|
void
|
|
_thread_sig_send(pthread_t pthread, int sig)
|
|
{
|
|
/*
|
|
* Check that the signal is not being ignored:
|
|
*/
|
|
if (_thread_sigact[sig - 1].sa_handler != SIG_IGN) {
|
|
if (pthread->state == PS_SIGWAIT &&
|
|
sigismember(pthread->data.sigwait, sig)) {
|
|
/* Change the state of the thread to run: */
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
} else if (pthread->state != PS_SIGWAIT &&
|
|
!sigismember(&pthread->sigmask, sig)) {
|
|
/* Perform any state changes due to signal arrival: */
|
|
thread_sig_check_state(pthread, sig);
|
|
}
|
|
|
|
/* Increment the pending signal count. */
|
|
sigaddset(&pthread->sigpend,sig);
|
|
}
|
|
}
|
|
|
|
/* Dispatch pending signals to the running thread: */
|
|
void
|
|
_dispatch_signals()
|
|
{
|
|
sigset_t sigset;
|
|
int i;
|
|
|
|
/*
|
|
* Check if there are pending signals for the running
|
|
* thread or process that aren't blocked:
|
|
*/
|
|
sigset = _thread_run->sigpend;
|
|
SIGSETOR(sigset, _process_sigpending);
|
|
SIGSETNAND(sigset, _thread_run->sigmask);
|
|
if (SIGNOTEMPTY(sigset)) {
|
|
/*
|
|
* Enter a loop to calculate deliverable pending signals
|
|
* before actually delivering them. The pending signals
|
|
* must be removed from the pending signal sets before
|
|
* calling the signal handler because the handler may
|
|
* call library routines that again check for and deliver
|
|
* pending signals.
|
|
*/
|
|
for (i = 1; i < NSIG; i++) {
|
|
/*
|
|
* Check that a custom handler is installed
|
|
* and if the signal is not blocked:
|
|
*/
|
|
if (_thread_sigact[i - 1].sa_handler != SIG_DFL &&
|
|
_thread_sigact[i - 1].sa_handler != SIG_IGN &&
|
|
sigismember(&sigset, i)) {
|
|
if (sigismember(&_thread_run->sigpend,i))
|
|
/* Clear the thread pending signal: */
|
|
sigdelset(&_thread_run->sigpend,i);
|
|
else
|
|
/* Clear the process pending signal: */
|
|
sigdelset(&_process_sigpending,i);
|
|
}
|
|
else
|
|
/* Remove the signal if it can't be handled: */
|
|
sigdelset(&sigset, i);
|
|
}
|
|
|
|
/* Now deliver the signals: */
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (sigismember(&sigset, i))
|
|
/* Deliver the signal to the running thread: */
|
|
_thread_sig_deliver(_thread_run, i);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Deliver a signal to a thread: */
|
|
void
|
|
_thread_sig_deliver(pthread_t pthread, int sig)
|
|
{
|
|
sigset_t mask;
|
|
pthread_t pthread_saved;
|
|
jmp_buf jb, *saved_sighandler_jmp_buf;
|
|
|
|
/*
|
|
* Check that a custom handler is installed
|
|
* and if the signal is not blocked:
|
|
*/
|
|
if (_thread_sigact[sig - 1].sa_handler != SIG_DFL &&
|
|
_thread_sigact[sig - 1].sa_handler != SIG_IGN) {
|
|
/* Save the current thread: */
|
|
pthread_saved = _thread_run;
|
|
|
|
/* Save the threads signal mask: */
|
|
mask = pthread->sigmask;
|
|
|
|
/*
|
|
* Add the current signal and signal handler
|
|
* mask to the thread's current signal mask:
|
|
*/
|
|
SIGSETOR(pthread->sigmask, _thread_sigact[sig - 1].sa_mask);
|
|
sigaddset(&pthread->sigmask, sig);
|
|
|
|
/* Current thread inside critical region? */
|
|
if (_thread_run->sig_defer_count > 0)
|
|
pthread->sig_defer_count++;
|
|
|
|
/* Increment the number of nested signals being handled. */
|
|
pthread->signal_nest_level++;
|
|
|
|
/*
|
|
* The jump buffer is allocated off the stack and the current
|
|
* jump buffer is saved. If the signal handler tries to
|
|
* [sig|_]longjmp(), our version of [sig|_]longjmp() will copy
|
|
* the user supplied jump buffer into
|
|
* _thread_run->nested_jmp.[sig]jmp and _longjmp() back to here.
|
|
*/
|
|
saved_sighandler_jmp_buf = pthread->sighandler_jmp_buf;
|
|
pthread->sighandler_jmp_buf = &jb;
|
|
|
|
_thread_run = pthread;
|
|
|
|
if (_setjmp(jb) == 0) {
|
|
/*
|
|
* Dispatch the signal via the custom signal
|
|
* handler:
|
|
*/
|
|
(*(_thread_sigact[sig - 1].sa_handler))(sig);
|
|
}
|
|
|
|
_thread_run = pthread_saved;
|
|
|
|
pthread->sighandler_jmp_buf = saved_sighandler_jmp_buf;
|
|
|
|
/* Decrement the signal nest level. */
|
|
pthread->signal_nest_level--;
|
|
|
|
/* Current thread inside critical region? */
|
|
if (_thread_run->sig_defer_count > 0)
|
|
pthread->sig_defer_count--;
|
|
|
|
/* Restore the threads signal mask: */
|
|
pthread->sigmask = mask;
|
|
}
|
|
}
|
|
#endif
|