6cc13fa9ad
a thread lock). Better protect access to thread state while searching for threads to handle a signal. Better protect access to process pending signals while processing a thread in sigwait(). Submitted by: davidxu
902 lines
26 KiB
C
902 lines
26 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 <errno.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <pthread.h>
|
|
#include "thr_private.h"
|
|
#include "pthread_md.h"
|
|
|
|
/* Prototypes: */
|
|
static void build_siginfo(siginfo_t *info, int signo);
|
|
static void thr_sig_add(struct pthread *pthread, int sig, siginfo_t *info);
|
|
static void thr_sig_check_state(struct pthread *pthread, int sig);
|
|
static struct pthread *thr_sig_find(struct kse *curkse, int sig,
|
|
siginfo_t *info);
|
|
static void handle_special_signals(struct kse *curkse, int sig);
|
|
static void thr_sigframe_add(struct pthread *thread, int sig,
|
|
siginfo_t *info);
|
|
static void thr_sigframe_restore(struct pthread *thread,
|
|
struct pthread_sigframe *psf);
|
|
static void thr_sigframe_save(struct pthread *thread,
|
|
struct pthread_sigframe *psf);
|
|
static void thr_sig_invoke_handler(struct pthread *, int sig,
|
|
siginfo_t *info, ucontext_t *ucp);
|
|
|
|
/* #define DEBUG_SIGNAL */
|
|
#ifdef DEBUG_SIGNAL
|
|
#define DBG_MSG stdout_debug
|
|
#else
|
|
#define DBG_MSG(x...)
|
|
#endif
|
|
|
|
/*
|
|
* Signal setup and delivery.
|
|
*
|
|
* 1) Delivering signals to threads in the same KSE.
|
|
* These signals are sent by upcall events and are set in the
|
|
* km_sigscaught field of the KSE mailbox. Since these signals
|
|
* are received while operating on the KSE stack, they can be
|
|
* delivered either by using signalcontext() to add a stack frame
|
|
* to the target thread's stack, or by adding them in the thread's
|
|
* pending set and having the thread run them down after it
|
|
* 2) Delivering signals to threads in other KSEs/KSEGs.
|
|
* 3) Delivering signals to threads in critical regions.
|
|
* 4) Delivering signals to threads after they change their signal masks.
|
|
*
|
|
* Methods of delivering signals.
|
|
*
|
|
* 1) Add a signal frame to the thread's saved context.
|
|
* 2) Add the signal to the thread structure, mark the thread as
|
|
* having signals to handle, and let the thread run them down
|
|
* after it resumes from the KSE scheduler.
|
|
*
|
|
* Problem with 1). You can't do this to a running thread or a
|
|
* thread in a critical region.
|
|
*
|
|
* Problem with 2). You can't do this to a thread that doesn't
|
|
* yield in some way (explicitly enters the scheduler). A thread
|
|
* blocked in the kernel or a CPU hungry thread will not see the
|
|
* signal without entering the scheduler.
|
|
*
|
|
* The solution is to use both 1) and 2) to deliver signals:
|
|
*
|
|
* o Thread in critical region - use 2). When the thread
|
|
* leaves the critical region it will check to see if it
|
|
* has pending signals and run them down.
|
|
*
|
|
* o Thread enters scheduler explicitly - use 2). The thread
|
|
* can check for pending signals after it returns from the
|
|
* the scheduler.
|
|
*
|
|
* o Thread is running and not current thread - use 2). When the
|
|
* thread hits a condition specified by one of the other bullets,
|
|
* the signal will be delivered.
|
|
*
|
|
* o Thread is running and is current thread (e.g., the thread
|
|
* has just changed its signal mask and now sees that it has
|
|
* pending signals) - just run down the pending signals.
|
|
*
|
|
* o Thread is swapped out due to quantum expiration - use 1)
|
|
*
|
|
* o Thread is blocked in kernel - kse_thr_wakeup() and then
|
|
* use 1)
|
|
*/
|
|
|
|
/*
|
|
* Rules for selecting threads for signals received:
|
|
*
|
|
* 1) If the signal is a sychronous signal, it is delivered to
|
|
* the generating (current thread). If the thread has the
|
|
* signal masked, it is added to the threads pending signal
|
|
* set until the thread unmasks it.
|
|
*
|
|
* 2) A thread in sigwait() where the signal is in the thread's
|
|
* waitset.
|
|
*
|
|
* 3) A thread in sigsuspend() where the signal is not in the
|
|
* thread's suspended signal mask.
|
|
*
|
|
* 4) Any thread (first found/easiest to deliver) that has the
|
|
* signal unmasked.
|
|
*/
|
|
|
|
/*
|
|
* This signal handler only delivers asynchronous signals.
|
|
* This must be called with upcalls disabled and without
|
|
* holding any locks.
|
|
*/
|
|
void
|
|
_thr_sig_dispatch(struct kse *curkse, int sig, siginfo_t *info)
|
|
{
|
|
struct pthread *thread;
|
|
|
|
DBG_MSG(">>> _thr_sig_dispatch(%d)\n", sig);
|
|
|
|
/* Some signals need special handling: */
|
|
handle_special_signals(curkse, sig);
|
|
|
|
if ((thread = thr_sig_find(curkse, sig, info)) != NULL) {
|
|
/*
|
|
* Setup the target thread to receive the signal:
|
|
*/
|
|
DBG_MSG("Got signal %d, selecting thread %p\n", sig, thread);
|
|
KSE_SCHED_LOCK(curkse, thread->kseg);
|
|
thr_sig_add(thread, sig, info);
|
|
KSE_SCHED_UNLOCK(curkse, thread->kseg);
|
|
}
|
|
}
|
|
|
|
void
|
|
_thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
|
|
{
|
|
void (*sigfunc)(int, siginfo_t *, void *);
|
|
struct kse *curkse;
|
|
|
|
curkse = _get_curkse();
|
|
if ((curkse == NULL) || ((curkse->k_flags & KF_STARTED) == 0)) {
|
|
/* Upcalls are not yet started; just call the handler. */
|
|
sigfunc = _thread_sigact[sig - 1].sa_sigaction;
|
|
ucp->uc_sigmask = _thr_proc_sigmask;
|
|
if (((__sighandler_t *)sigfunc != SIG_DFL) &&
|
|
((__sighandler_t *)sigfunc != SIG_IGN)) {
|
|
if (((_thread_sigact[sig - 1].sa_flags & SA_SIGINFO)
|
|
!= 0) || (info == NULL))
|
|
(*(sigfunc))(sig, info, ucp);
|
|
else
|
|
(*(sigfunc))(sig, (siginfo_t *)info->si_code,
|
|
ucp);
|
|
}
|
|
}
|
|
else {
|
|
/* Nothing. */
|
|
DBG_MSG("Got signal %d\n", sig);
|
|
sigaddset(&curkse->k_mbx.km_sigscaught, sig);
|
|
ucp->uc_sigmask = _thr_proc_sigmask;
|
|
}
|
|
}
|
|
|
|
static void
|
|
thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
|
|
ucontext_t *ucp)
|
|
{
|
|
void (*sigfunc)(int, siginfo_t *, void *);
|
|
sigset_t saved_mask;
|
|
int saved_seqno;
|
|
|
|
/* Invoke the signal handler without going through the scheduler:
|
|
*/
|
|
DBG_MSG("Got signal %d, calling handler for current thread %p\n",
|
|
sig, curthread);
|
|
|
|
/*
|
|
* Setup the threads signal mask.
|
|
*
|
|
* The mask is changed in the thread's active signal mask
|
|
* (in the context) and not in the base signal mask because
|
|
* a thread is allowed to change its signal mask within a
|
|
* signal handler. If it does, the signal mask restored
|
|
* after the handler should be the same as that set by the
|
|
* thread during the handler, not the original mask from
|
|
* before calling the handler. The thread could also
|
|
* modify the signal mask in the context and expect this
|
|
* mask to be used.
|
|
*/
|
|
THR_SCHED_LOCK(curthread, curthread);
|
|
saved_mask = curthread->tmbx.tm_context.uc_sigmask;
|
|
saved_seqno = curthread->sigmask_seqno;
|
|
SIGSETOR(curthread->tmbx.tm_context.uc_sigmask,
|
|
_thread_sigact[sig - 1].sa_mask);
|
|
sigaddset(&curthread->tmbx.tm_context.uc_sigmask, sig);
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
|
|
/*
|
|
* Check that a custom handler is installed and if
|
|
* the signal is not blocked:
|
|
*/
|
|
sigfunc = _thread_sigact[sig - 1].sa_sigaction;
|
|
ucp->uc_sigmask = _thr_proc_sigmask;
|
|
if (((__sighandler_t *)sigfunc != SIG_DFL) &&
|
|
((__sighandler_t *)sigfunc != SIG_IGN)) {
|
|
if (((_thread_sigact[sig - 1].sa_flags & SA_SIGINFO) != 0) ||
|
|
(info == NULL))
|
|
(*(sigfunc))(sig, info, ucp);
|
|
else
|
|
(*(sigfunc))(sig, (siginfo_t *)info->si_code, ucp);
|
|
}
|
|
|
|
/*
|
|
* Restore the thread's signal mask.
|
|
*/
|
|
if (saved_seqno == curthread->sigmask_seqno)
|
|
curthread->tmbx.tm_context.uc_sigmask = saved_mask;
|
|
else
|
|
curthread->tmbx.tm_context.uc_sigmask = curthread->sigmask;
|
|
}
|
|
|
|
/*
|
|
* Find a thread that can handle the signal. This must be called
|
|
* with upcalls disabled.
|
|
*/
|
|
struct pthread *
|
|
thr_sig_find(struct kse *curkse, int sig, siginfo_t *info)
|
|
{
|
|
int handler_installed;
|
|
struct pthread *pthread;
|
|
struct pthread *suspended_thread, *signaled_thread;
|
|
|
|
DBG_MSG("Looking for thread to handle signal %d\n", sig);
|
|
|
|
handler_installed = (_thread_sigact[sig - 1].sa_handler != SIG_IGN) &&
|
|
(_thread_sigact[sig - 1].sa_handler != SIG_DFL);
|
|
|
|
/* Check if the signal requires a dump of thread information: */
|
|
if (sig == SIGINFO) {
|
|
/* Dump thread information to file: */
|
|
_thread_dump_info();
|
|
}
|
|
/*
|
|
* 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. Third
|
|
* preference will be the current thread. If none of the
|
|
* above, then the signal is delivered to the first thread
|
|
* that is found. Note that if a custom handler is not
|
|
* installed, the signal only affects threads in sigwait.
|
|
*/
|
|
suspended_thread = NULL;
|
|
signaled_thread = NULL;
|
|
|
|
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
|
|
TAILQ_FOREACH(pthread, &_thread_list, tle) {
|
|
/* Take the scheduling lock. */
|
|
KSE_SCHED_LOCK(curkse, pthread->kseg);
|
|
if ((pthread->state == PS_SIGWAIT) &&
|
|
sigismember(pthread->data.sigwait, sig)) {
|
|
/*
|
|
* Return the signal number and make the
|
|
* thread runnable.
|
|
*/
|
|
pthread->signo = sig;
|
|
_thr_setrunnable_unlocked(pthread);
|
|
|
|
KSE_SCHED_UNLOCK(curkse, pthread->kseg);
|
|
|
|
/*
|
|
* 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 and do not add the signal
|
|
* to the process pending set.
|
|
*/
|
|
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
|
|
DBG_MSG("Waking thread %p in sigwait with signal %d\n",
|
|
pthread, sig);
|
|
return (NULL);
|
|
}
|
|
else if ((pthread->state == PS_DEAD) ||
|
|
(pthread->state == PS_DEADLOCK) ||
|
|
((pthread->flags & THR_FLAGS_EXITING) != 0))
|
|
; /* Skip this thread. */
|
|
else if ((handler_installed != 0) &&
|
|
!sigismember(&pthread->tmbx.tm_context.uc_sigmask, sig) &&
|
|
((pthread->flags & THR_FLAGS_SUSPENDED) == 0)) {
|
|
if (pthread->state == PS_SIGSUSPEND) {
|
|
if (suspended_thread == NULL)
|
|
suspended_thread = pthread;
|
|
} else if (signaled_thread == NULL)
|
|
signaled_thread = pthread;
|
|
}
|
|
KSE_SCHED_UNLOCK(curkse, pthread->kseg);
|
|
}
|
|
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
|
|
|
|
/*
|
|
* Only perform wakeups and signal delivery if there is a
|
|
* custom handler installed:
|
|
*/
|
|
if (handler_installed == 0) {
|
|
/*
|
|
* There is no handler installed; nothing to do here.
|
|
*/
|
|
} else if (suspended_thread == NULL &&
|
|
signaled_thread == NULL) {
|
|
/*
|
|
* Add it to the set of signals pending
|
|
* on the process:
|
|
*/
|
|
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
|
|
if (!sigismember(&_thr_proc_sigpending, sig)) {
|
|
sigaddset(&_thr_proc_sigpending, sig);
|
|
if (info == NULL)
|
|
build_siginfo(&_thr_proc_siginfo[sig], sig);
|
|
else
|
|
memcpy(&_thr_proc_siginfo[sig], info,
|
|
sizeof(*info));
|
|
}
|
|
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
|
|
} 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;
|
|
return (pthread);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
build_siginfo(siginfo_t *info, int signo)
|
|
{
|
|
bzero(info, sizeof(*info));
|
|
info->si_signo = signo;
|
|
info->si_pid = _thr_pid;
|
|
}
|
|
|
|
/*
|
|
* This is called by a thread when it has pending signals to deliver.
|
|
* It should only be called from the context of the thread.
|
|
*/
|
|
void
|
|
_thr_sig_rundown(struct pthread *curthread, ucontext_t *ucp,
|
|
struct pthread_sigframe *psf)
|
|
{
|
|
struct pthread_sigframe psf_save;
|
|
sigset_t sigset;
|
|
int i;
|
|
|
|
THR_SCHED_LOCK(curthread, curthread);
|
|
memcpy(&sigset, &curthread->sigpend, sizeof(sigset));
|
|
sigemptyset(&curthread->sigpend);
|
|
if (psf != NULL) {
|
|
memcpy(&psf_save, psf, sizeof(*psf));
|
|
SIGSETOR(sigset, psf_save.psf_sigset);
|
|
sigemptyset(&psf->psf_sigset);
|
|
}
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
|
|
/* Check the threads previous state: */
|
|
if ((psf != NULL) && (psf_save.psf_state != PS_RUNNING)) {
|
|
/*
|
|
* Do a little cleanup handling for those threads in
|
|
* queues before calling the signal handler. Signals
|
|
* for these threads are temporarily blocked until
|
|
* after cleanup handling.
|
|
*/
|
|
switch (psf_save.psf_state) {
|
|
case PS_COND_WAIT:
|
|
_cond_wait_backout(curthread);
|
|
psf_save.psf_state = PS_RUNNING;
|
|
break;
|
|
|
|
case PS_MUTEX_WAIT:
|
|
_mutex_lock_backout(curthread);
|
|
psf_save.psf_state = PS_RUNNING;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* Lower the priority before calling the handler in case
|
|
* it never returns (longjmps back):
|
|
*/
|
|
curthread->active_priority &= ~THR_SIGNAL_PRIORITY;
|
|
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (sigismember(&sigset, i) != 0) {
|
|
/* Call the handler: */
|
|
thr_sig_invoke_handler(curthread, i,
|
|
&curthread->siginfo[i], ucp);
|
|
}
|
|
}
|
|
|
|
THR_SCHED_LOCK(curthread, curthread);
|
|
if (psf != NULL)
|
|
thr_sigframe_restore(curthread, &psf_save);
|
|
/* Restore the signal mask. */
|
|
curthread->tmbx.tm_context.uc_sigmask = curthread->sigmask;
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
_thr_sig_check_pending(curthread);
|
|
}
|
|
|
|
/*
|
|
* This checks pending signals for the current thread. It should be
|
|
* called whenever a thread changes its signal mask. Note that this
|
|
* is called from a thread (using its stack).
|
|
*
|
|
* XXX - We might want to just check to see if there are pending
|
|
* signals for the thread here, but enter the UTS scheduler
|
|
* to actually install the signal handler(s).
|
|
*/
|
|
void
|
|
_thr_sig_check_pending(struct pthread *curthread)
|
|
{
|
|
sigset_t sigset;
|
|
sigset_t pending_process;
|
|
sigset_t pending_thread;
|
|
kse_critical_t crit;
|
|
int i;
|
|
|
|
curthread->check_pending = 0;
|
|
|
|
/*
|
|
* Check if there are pending signals for the running
|
|
* thread or process that aren't blocked:
|
|
*/
|
|
crit = _kse_critical_enter();
|
|
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
|
|
sigset = _thr_proc_sigpending;
|
|
KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
|
|
_kse_critical_leave(crit);
|
|
|
|
THR_SCHED_LOCK(curthread, curthread);
|
|
SIGSETOR(sigset, curthread->sigpend);
|
|
SIGSETNAND(sigset, curthread->tmbx.tm_context.uc_sigmask);
|
|
if (SIGNOTEMPTY(sigset)) {
|
|
ucontext_t uc;
|
|
volatile int once;
|
|
|
|
curthread->check_pending = 0;
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
|
|
/*
|
|
* Split the pending signals into those that were
|
|
* pending on the process and those that were pending
|
|
* on the thread.
|
|
*/
|
|
sigfillset(&pending_process);
|
|
sigfillset(&pending_thread);
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (sigismember(&sigset, i) != 0) {
|
|
if (sigismember(&curthread->sigpend, i) != 0) {
|
|
build_siginfo(&curthread->siginfo[i], i);
|
|
sigdelset(&pending_thread, i);
|
|
} else {
|
|
memcpy(&curthread->siginfo[i],
|
|
&_thr_proc_siginfo[i],
|
|
sizeof(siginfo_t));
|
|
sigdelset(&pending_process, i);
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* Remove any process pending signals that were scheduled
|
|
* to be delivered from process' pending set.
|
|
*/
|
|
crit = _kse_critical_enter();
|
|
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
|
|
SIGSETAND(_thr_proc_sigpending, pending_process);
|
|
KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
|
|
_kse_critical_leave(crit);
|
|
|
|
/*
|
|
* Remove any thread pending signals that were scheduled
|
|
* to be delivered from thread's pending set.
|
|
*/
|
|
THR_SCHED_LOCK(curthread, curthread);
|
|
SIGSETAND(curthread->sigpend, pending_thread);
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
|
|
once = 0;
|
|
THR_GETCONTEXT(&uc);
|
|
if (once == 0) {
|
|
once = 1;
|
|
for (i = 1; i < NSIG; i++) {
|
|
if (sigismember(&sigset, i) != 0) {
|
|
/* Call the handler: */
|
|
thr_sig_invoke_handler(curthread, i,
|
|
&curthread->siginfo[i], &uc);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
else
|
|
THR_SCHED_UNLOCK(curthread, curthread);
|
|
}
|
|
|
|
/*
|
|
* This must be called with upcalls disabled.
|
|
*/
|
|
static void
|
|
handle_special_signals(struct kse *curkse, int sig)
|
|
{
|
|
switch (sig) {
|
|
/*
|
|
* POSIX says that pending SIGCONT signals are
|
|
* discarded when one of these signals occurs.
|
|
*/
|
|
case SIGTSTP:
|
|
case SIGTTIN:
|
|
case SIGTTOU:
|
|
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
|
|
sigdelset(&_thr_proc_sigpending, SIGCONT);
|
|
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Perform thread specific actions in response to a signal.
|
|
* This function is only called if there is a handler installed
|
|
* for the signal, and if the target thread has the signal
|
|
* unmasked.
|
|
*
|
|
* This must be called with the thread's scheduling lock held.
|
|
*/
|
|
static void
|
|
thr_sig_add(struct pthread *pthread, int sig, siginfo_t *info)
|
|
{
|
|
int restart;
|
|
int suppress_handler = 0;
|
|
|
|
restart = _thread_sigact[sig - 1].sa_flags & SA_RESTART;
|
|
|
|
/* Make sure this signal isn't still in the pending set: */
|
|
sigdelset(&pthread->sigpend, sig);
|
|
|
|
/*
|
|
* Process according to thread state:
|
|
*/
|
|
switch (pthread->state) {
|
|
/*
|
|
* States which do not change when a signal is trapped:
|
|
*/
|
|
case PS_DEAD:
|
|
case PS_DEADLOCK:
|
|
case PS_LOCKWAIT:
|
|
case PS_SUSPENDED:
|
|
case PS_STATE_MAX:
|
|
/*
|
|
* You can't call a signal handler for threads in these
|
|
* states.
|
|
*/
|
|
suppress_handler = 1;
|
|
break;
|
|
|
|
/*
|
|
* States which do not need any cleanup handling when signals
|
|
* occur:
|
|
*/
|
|
case PS_RUNNING:
|
|
/*
|
|
* Remove the thread from the queue before changing its
|
|
* priority:
|
|
*/
|
|
if ((pthread->flags & THR_FLAGS_IN_RUNQ) != 0)
|
|
THR_RUNQ_REMOVE(pthread);
|
|
else {
|
|
/*
|
|
* This thread is active; add the signal to the
|
|
* pending set and mark it as having pending
|
|
* signals.
|
|
*/
|
|
suppress_handler = 1;
|
|
sigaddset(&pthread->sigpend, sig);
|
|
build_siginfo(&pthread->siginfo[sig], sig);
|
|
pthread->check_pending = 1;
|
|
if ((pthread->blocked != 0) &&
|
|
!THR_IN_CRITICAL(pthread))
|
|
kse_thr_interrupt(&pthread->tmbx /* XXX - restart?!?! */);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* States which cannot be interrupted but still require the
|
|
* signal handler to run:
|
|
*/
|
|
case PS_COND_WAIT:
|
|
case PS_MUTEX_WAIT:
|
|
/*
|
|
* Remove the thread from the wait queue. It will
|
|
* be added back to the wait queue once all signal
|
|
* handlers have been invoked.
|
|
*/
|
|
KSE_WAITQ_REMOVE(pthread->kse, pthread);
|
|
break;
|
|
|
|
case PS_SLEEP_WAIT:
|
|
/*
|
|
* Unmasked signals always cause sleep to terminate early,
|
|
* regardless of SA_RESTART:
|
|
*/
|
|
pthread->interrupted = 1;
|
|
KSE_WAITQ_REMOVE(pthread->kse, pthread);
|
|
THR_SET_STATE(pthread, PS_RUNNING);
|
|
break;
|
|
|
|
case PS_JOIN:
|
|
case PS_SIGSUSPEND:
|
|
KSE_WAITQ_REMOVE(pthread->kse, pthread);
|
|
THR_SET_STATE(pthread, PS_RUNNING);
|
|
break;
|
|
|
|
case PS_SIGWAIT:
|
|
/* The signal handler is not called for threads in SIGWAIT. */
|
|
suppress_handler = 1;
|
|
/* Wake up the thread if the signal is blocked. */
|
|
if (sigismember(pthread->data.sigwait, sig)) {
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
|
|
/* Make the thread runnable: */
|
|
_thr_setrunnable_unlocked(pthread);
|
|
} else
|
|
/* Increment the pending signal count. */
|
|
sigaddset(&pthread->sigpend, sig);
|
|
break;
|
|
}
|
|
|
|
if (suppress_handler == 0) {
|
|
if (pthread->curframe == NULL) {
|
|
/*
|
|
* This thread is active. Just add it to the
|
|
* thread's pending set.
|
|
*/
|
|
sigaddset(&pthread->sigpend, sig);
|
|
pthread->check_pending = 1;
|
|
if (info == NULL)
|
|
build_siginfo(&pthread->siginfo[sig], sig);
|
|
else
|
|
memcpy(&pthread->siginfo[sig], info,
|
|
sizeof(*info));
|
|
} else {
|
|
/*
|
|
* Setup a signal frame and save the current threads
|
|
* state:
|
|
*/
|
|
thr_sigframe_add(pthread, sig, info);
|
|
}
|
|
|
|
if (pthread->state != PS_RUNNING)
|
|
THR_SET_STATE(pthread, PS_RUNNING);
|
|
|
|
/*
|
|
* The thread should be removed from all scheduling
|
|
* queues at this point. Raise the priority and
|
|
* place the thread in the run queue. It is also
|
|
* possible for a signal to be sent to a suspended
|
|
* thread, mostly via pthread_kill(). If a thread
|
|
* is suspended, don't insert it into the priority
|
|
* queue; just set its state to suspended and it
|
|
* will run the signal handler when it is resumed.
|
|
*/
|
|
pthread->active_priority |= THR_SIGNAL_PRIORITY;
|
|
if ((pthread->flags & THR_FLAGS_SUSPENDED) != 0)
|
|
THR_SET_STATE(pthread, PS_SUSPENDED);
|
|
else if ((pthread->flags & THR_FLAGS_IN_RUNQ) == 0)
|
|
THR_RUNQ_INSERT_TAIL(pthread);
|
|
}
|
|
}
|
|
|
|
static void
|
|
thr_sig_check_state(struct pthread *pthread, int sig)
|
|
{
|
|
/*
|
|
* Process according to thread state:
|
|
*/
|
|
switch (pthread->state) {
|
|
/*
|
|
* States which do not change when a signal is trapped:
|
|
*/
|
|
case PS_RUNNING:
|
|
case PS_LOCKWAIT:
|
|
case PS_MUTEX_WAIT:
|
|
case PS_COND_WAIT:
|
|
case PS_JOIN:
|
|
case PS_SUSPENDED:
|
|
case PS_DEAD:
|
|
case PS_DEADLOCK:
|
|
case PS_STATE_MAX:
|
|
break;
|
|
|
|
case PS_SIGWAIT:
|
|
/* Wake up the thread if the signal is blocked. */
|
|
if (sigismember(pthread->data.sigwait, sig)) {
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
|
|
/* Change the state of the thread to run: */
|
|
_thr_setrunnable_unlocked(pthread);
|
|
} else
|
|
/* Increment the pending signal count. */
|
|
sigaddset(&pthread->sigpend, sig);
|
|
break;
|
|
|
|
case PS_SIGSUSPEND:
|
|
case PS_SLEEP_WAIT:
|
|
/*
|
|
* Remove the thread from the wait queue and make it
|
|
* runnable:
|
|
*/
|
|
_thr_setrunnable_unlocked(pthread);
|
|
|
|
/* Flag the operation as interrupted: */
|
|
pthread->interrupted = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send a signal to a specific thread (ala pthread_kill):
|
|
*/
|
|
void
|
|
_thr_sig_send(struct pthread *pthread, int sig)
|
|
{
|
|
struct pthread *curthread = _get_curthread();
|
|
|
|
/* Lock the scheduling queue of the target thread. */
|
|
THR_SCHED_LOCK(curthread, pthread);
|
|
|
|
/* Check for signals whose actions are SIG_DFL: */
|
|
if (_thread_sigact[sig - 1].sa_handler == SIG_DFL) {
|
|
/*
|
|
* Check to see if a temporary signal handler is
|
|
* installed for sigwaiters:
|
|
*/
|
|
if (_thread_dfl_count[sig] == 0) {
|
|
/*
|
|
* Deliver the signal to the process if a handler
|
|
* is not installed:
|
|
*/
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
kill(getpid(), sig);
|
|
THR_SCHED_LOCK(curthread, pthread);
|
|
}
|
|
/*
|
|
* Assuming we're still running after the above kill(),
|
|
* make any necessary state changes to the thread:
|
|
*/
|
|
thr_sig_check_state(pthread, sig);
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
}
|
|
/*
|
|
* Check that the signal is not being ignored:
|
|
*/
|
|
else if (_thread_sigact[sig - 1].sa_handler != SIG_IGN) {
|
|
if (pthread->state == PS_SIGWAIT &&
|
|
sigismember(pthread->data.sigwait, sig)) {
|
|
/* Return the signal number: */
|
|
pthread->signo = sig;
|
|
|
|
/* Change the state of the thread to run: */
|
|
_thr_setrunnable_unlocked(pthread);
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
} else if (sigismember(&pthread->tmbx.tm_context.uc_sigmask, sig)) {
|
|
/* Add the signal to the pending set: */
|
|
sigaddset(&pthread->sigpend, sig);
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
} else if (pthread == curthread) {
|
|
ucontext_t uc;
|
|
siginfo_t info;
|
|
volatile int once;
|
|
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
build_siginfo(&info, sig);
|
|
once = 0;
|
|
THR_GETCONTEXT(&uc);
|
|
if (once == 0) {
|
|
once = 1;
|
|
/*
|
|
* Call the signal handler for the current
|
|
* thread:
|
|
*/
|
|
thr_sig_invoke_handler(curthread, sig,
|
|
&info, &uc);
|
|
}
|
|
} else {
|
|
/*
|
|
* Perform any state changes due to signal
|
|
* arrival:
|
|
*/
|
|
thr_sig_add(pthread, sig, NULL);
|
|
THR_SCHED_UNLOCK(curthread, pthread);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
thr_sigframe_add(struct pthread *thread, int sig, siginfo_t *info)
|
|
{
|
|
if (thread->curframe == NULL)
|
|
PANIC("Thread doesn't have signal frame ");
|
|
|
|
if (thread->check_pending == 0) {
|
|
/*
|
|
* Multiple signals can be added to the same signal
|
|
* frame. Only save the thread's state the first time.
|
|
*/
|
|
thr_sigframe_save(thread, thread->curframe);
|
|
thread->check_pending = 1;
|
|
thread->flags &= THR_FLAGS_PRIVATE;
|
|
}
|
|
sigaddset(&thread->curframe->psf_sigset, sig);
|
|
if (info != NULL)
|
|
memcpy(&thread->siginfo[sig], info, sizeof(*info));
|
|
else
|
|
build_siginfo(&thread->siginfo[sig], sig);
|
|
|
|
/* Setup the new signal mask. */
|
|
SIGSETOR(thread->tmbx.tm_context.uc_sigmask,
|
|
_thread_sigact[sig - 1].sa_mask);
|
|
sigaddset(&thread->tmbx.tm_context.uc_sigmask, sig);
|
|
}
|
|
|
|
void
|
|
thr_sigframe_restore(struct pthread *thread, struct pthread_sigframe *psf)
|
|
{
|
|
thread->flags = psf->psf_flags;
|
|
thread->interrupted = psf->psf_interrupted;
|
|
thread->signo = psf->psf_signo;
|
|
thread->state = psf->psf_state;
|
|
thread->data = psf->psf_wait_data;
|
|
thread->wakeup_time = psf->psf_wakeup_time;
|
|
if (thread->sigmask_seqno == psf->psf_seqno)
|
|
thread->tmbx.tm_context.uc_sigmask = psf->psf_sigmask;
|
|
else
|
|
thread->tmbx.tm_context.uc_sigmask = thread->sigmask;
|
|
}
|
|
|
|
static void
|
|
thr_sigframe_save(struct pthread *thread, struct pthread_sigframe *psf)
|
|
{
|
|
/* This has to initialize all members of the sigframe. */
|
|
psf->psf_flags = thread->flags & THR_FLAGS_PRIVATE;
|
|
psf->psf_interrupted = thread->interrupted;
|
|
psf->psf_signo = thread->signo;
|
|
psf->psf_state = thread->state;
|
|
psf->psf_wait_data = thread->data;
|
|
psf->psf_wakeup_time = thread->wakeup_time;
|
|
psf->psf_sigmask = thread->tmbx.tm_context.uc_sigmask;
|
|
psf->psf_seqno = thread->sigmask_seqno;
|
|
sigemptyset(&psf->psf_sigset);
|
|
}
|