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freebsd-nq/lib/libpthread/thread/thr_sig.c
David Xu 5321c2a9b0 Check pending signals, if there is signal will be unblocked by 
sigsuspend, thread shouldn't wait, in old code, it may be
ignored.
When a signal handler is invoked in sigsuspend, thread gets
two different signal masks, one is in thread structure,
sigprocmask() can retrieve it, another is in ucontext
which is a third parameter of signal handler, the former is
the result of sigsuspend mask ORed with sigaction's sa_mask
and current signal, the later is the mask in thread structure
before sigsuspend is called. After signal handler is called,
the mask in ucontext should be copied into thread structure,
and becomes CURRENT signal mask, then sigsuspend returns to
user code.

Reviewed by: deischen
Tested by: Sean McNeil <sean@mcneil.com>
2004-06-12 07:40:01 +00:00

1270 lines
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/*
* 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"
/* Prototypes: */
static void build_siginfo(siginfo_t *info, int signo);
#ifndef SYSTEM_SCOPE_ONLY
static struct pthread *thr_sig_find(struct kse *curkse, int sig,
siginfo_t *info);
static void handle_special_signals(struct kse *curkse, int sig);
#endif
static void thr_sigframe_add(struct pthread *thread);
static void thr_sigframe_restore(struct pthread *thread,
struct pthread_sigframe *psf);
static void thr_sigframe_save(struct pthread *thread,
struct pthread_sigframe *psf);
#define SA_KILL 0x01 /* terminates process by default */
#define SA_STOP 0x02
#define SA_CONT 0x04
static int sigproptbl[NSIG] = {
SA_KILL, /* SIGHUP */
SA_KILL, /* SIGINT */
SA_KILL, /* SIGQUIT */
SA_KILL, /* SIGILL */
SA_KILL, /* SIGTRAP */
SA_KILL, /* SIGABRT */
SA_KILL, /* SIGEMT */
SA_KILL, /* SIGFPE */
SA_KILL, /* SIGKILL */
SA_KILL, /* SIGBUS */
SA_KILL, /* SIGSEGV */
SA_KILL, /* SIGSYS */
SA_KILL, /* SIGPIPE */
SA_KILL, /* SIGALRM */
SA_KILL, /* SIGTERM */
0, /* SIGURG */
SA_STOP, /* SIGSTOP */
SA_STOP, /* SIGTSTP */
SA_CONT, /* SIGCONT */
0, /* SIGCHLD */
SA_STOP, /* SIGTTIN */
SA_STOP, /* SIGTTOU */
0, /* SIGIO */
SA_KILL, /* SIGXCPU */
SA_KILL, /* SIGXFSZ */
SA_KILL, /* SIGVTALRM */
SA_KILL, /* SIGPROF */
0, /* SIGWINCH */
0, /* SIGINFO */
SA_KILL, /* SIGUSR1 */
SA_KILL /* SIGUSR2 */
};
/* #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.
*/
#ifndef SYSTEM_SCOPE_ONLY
static void *
sig_daemon(void *arg /* Unused */)
{
int i;
kse_critical_t crit;
struct timespec ts;
sigset_t set;
struct kse *curkse;
struct pthread *curthread = _get_curthread();
DBG_MSG("signal daemon started(%p)\n", curthread);
curthread->name = strdup("signal thread");
crit = _kse_critical_enter();
curkse = _get_curkse();
/*
* Daemon thread is a bound thread and we must be created with
* all signals masked
*/
#if 0
SIGFILLSET(set);
__sys_sigprocmask(SIG_SETMASK, &set, NULL);
#endif
__sys_sigpending(&set);
ts.tv_sec = 0;
ts.tv_nsec = 0;
while (1) {
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
_thr_proc_sigpending = set;
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
for (i = 1; i <= _SIG_MAXSIG; i++) {
if (SIGISMEMBER(set, i) != 0)
_thr_sig_dispatch(curkse, i,
NULL /* no siginfo */);
}
ts.tv_sec = 30;
ts.tv_nsec = 0;
curkse->k_kcb->kcb_kmbx.km_flags =
KMF_NOUPCALL | KMF_NOCOMPLETED | KMF_WAITSIGEVENT;
kse_release(&ts);
curkse->k_kcb->kcb_kmbx.km_flags = 0;
set = curkse->k_kcb->kcb_kmbx.km_sigscaught;
}
return (0);
}
/* Utility function to create signal daemon thread */
int
_thr_start_sig_daemon(void)
{
pthread_attr_t attr;
sigset_t sigset, oldset;
SIGFILLSET(sigset);
pthread_sigmask(SIG_SETMASK, &sigset, &oldset);
pthread_attr_init(&attr);
pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
/* sigmask will be inherited */
if (pthread_create(&_thr_sig_daemon, &attr, sig_daemon, NULL))
PANIC("can not create signal daemon thread!\n");
pthread_attr_destroy(&attr);
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
return (0);
}
/*
* 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 kse_mailbox *kmbx;
struct pthread *thread;
DBG_MSG(">>> _thr_sig_dispatch(%d)\n", sig);
/* Some signals need special handling: */
handle_special_signals(curkse, sig);
/* Check if the signal requires a dump of thread information: */
if (sig == SIGINFO) {
/* Dump thread information to file: */
_thread_dump_info();
}
while ((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);
if ((thread->state == PS_DEAD) ||
(thread->state == PS_DEADLOCK) ||
THR_IS_EXITING(thread) || THR_IS_SUSPENDED(thread)) {
KSE_SCHED_UNLOCK(curkse, thread->kseg);
_thr_ref_delete(NULL, thread);
} else if (SIGISMEMBER(thread->sigmask, sig)) {
KSE_SCHED_UNLOCK(curkse, thread->kseg);
_thr_ref_delete(NULL, thread);
} else {
kmbx = _thr_sig_add(thread, sig, info);
KSE_SCHED_UNLOCK(curkse, thread->kseg);
_thr_ref_delete(NULL, thread);
if (kmbx != NULL)
kse_wakeup(kmbx);
break;
}
}
DBG_MSG("<<< _thr_sig_dispatch\n");
}
#endif /* ! SYSTEM_SCOPE_ONLY */
static __inline int
sigprop(int sig)
{
if (sig > 0 && sig < NSIG)
return (sigproptbl[_SIG_IDX(sig)]);
return (0);
}
typedef void (*ohandler)(int sig, int code,
struct sigcontext *scp, char *addr, __sighandler_t *catcher);
void
_thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
{
__siginfohandler_t *sigfunc;
struct pthread *curthread;
struct kse *curkse;
struct sigaction act;
int sa_flags, err_save, intr_save, timeout_save;
DBG_MSG(">>> _thr_sig_handler(%d)\n", sig);
curthread = _get_curthread();
if (curthread == NULL)
PANIC("No current thread.\n");
if (!(curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
PANIC("Thread is not system scope.\n");
if (curthread->flags & THR_FLAGS_EXITING)
return;
curkse = _get_curkse();
/*
* If thread is in critical region or if thread is on
* the way of state transition, then latch signal into buffer.
*/
if (_kse_in_critical() || THR_IN_CRITICAL(curthread) ||
(curthread->state != PS_RUNNING && curthread->curframe == NULL)) {
DBG_MSG(">>> _thr_sig_handler(%d) in critical\n", sig);
curthread->siginfo[sig-1] = *info;
curthread->check_pending = 1;
curkse->k_sigseqno++;
SIGADDSET(curthread->sigpend, sig);
/*
* If the kse is on the way to idle itself, but
* we have signal ready, we should prevent it
* to sleep, kernel will latch the wakeup request,
* so kse_release will return from kernel immediately.
*/
if (KSE_IS_IDLE(curkse))
kse_wakeup(&curkse->k_kcb->kcb_kmbx);
return;
}
/* It is now safe to invoke signal handler */
err_save = errno;
timeout_save = curthread->timeout;
intr_save = curthread->interrupted;
_kse_critical_enter();
/* Get a fresh copy of signal mask */
__sys_sigprocmask(SIG_BLOCK, NULL, &curthread->sigmask);
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
sigfunc = _thread_sigact[sig - 1].sa_sigaction;
sa_flags = _thread_sigact[sig - 1].sa_flags;
if (sa_flags & SA_RESETHAND) {
act.sa_handler = SIG_DFL;
act.sa_flags = SA_RESTART;
SIGEMPTYSET(act.sa_mask);
__sys_sigaction(sig, &act, NULL);
__sys_sigaction(sig, NULL, &_thread_sigact[sig - 1]);
}
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
/* Now invoke real handler */
if (((__sighandler_t *)sigfunc != SIG_DFL) &&
((__sighandler_t *)sigfunc != SIG_IGN) &&
(sigfunc != (__siginfohandler_t *)_thr_sig_handler)) {
if ((sa_flags & SA_SIGINFO) != 0 || info == NULL)
(*(sigfunc))(sig, info, ucp);
else {
((ohandler)(*sigfunc))(
sig, info->si_code, (struct sigcontext *)ucp,
info->si_addr, (__sighandler_t *)sigfunc);
}
} else {
if ((__sighandler_t *)sigfunc == SIG_DFL) {
if (sigprop(sig) & SA_KILL) {
if (_kse_isthreaded())
kse_thr_interrupt(NULL,
KSE_INTR_SIGEXIT, sig);
else
kill(getpid(), sig);
}
#ifdef NOTYET
else if (sigprop(sig) & SA_STOP)
kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP, sig);
#endif
}
}
errno = err_save;
curthread->timeout = timeout_save;
curthread->interrupted = intr_save;
_kse_critical_enter();
curthread->sigmask = ucp->uc_sigmask;
SIG_CANTMASK(curthread->sigmask);
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
DBG_MSG("<<< _thr_sig_handler(%d)\n", sig);
}
struct sighandle_info {
__siginfohandler_t *sigfunc;
int sa_flags;
int sig;
siginfo_t *info;
ucontext_t *ucp;
};
static void handle_signal(struct pthread *curthread,
struct sighandle_info *shi);
static void handle_signal_altstack(struct pthread *curthread,
struct sighandle_info *shi);
/* Must be called with signal lock and schedule lock held in order */
static void
thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
ucontext_t *ucp)
{
__siginfohandler_t *sigfunc;
sigset_t sigmask;
int sa_flags;
int onstack;
struct sigaction act;
struct kse *curkse;
struct sighandle_info shi;
/*
* Invoke the signal handler without going through the scheduler:
*/
DBG_MSG("Got signal %d, calling handler for current thread %p\n",
sig, curthread);
if (!_kse_in_critical())
PANIC("thr_sig_invoke_handler without in critical\n");
curkse = _get_curkse();
/*
* Check that a custom handler is installed and if
* the signal is not blocked:
*/
sigfunc = _thread_sigact[sig - 1].sa_sigaction;
sa_flags = _thread_sigact[sig - 1].sa_flags;
sigmask = curthread->sigmask;
SIGSETOR(curthread->sigmask, _thread_sigact[sig - 1].sa_mask);
if (!(sa_flags & (SA_NODEFER | SA_RESETHAND)))
SIGADDSET(curthread->sigmask, sig);
if ((sig != SIGILL) && (sa_flags & SA_RESETHAND)) {
act.sa_handler = SIG_DFL;
act.sa_flags = SA_RESTART;
SIGEMPTYSET(act.sa_mask);
__sys_sigaction(sig, &act, NULL);
__sys_sigaction(sig, NULL, &_thread_sigact[sig - 1]);
}
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
/*
* We are processing buffered signals, synchronize working
* signal mask into kernel.
*/
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
onstack = _thr_sigonstack(&sigfunc);
ucp->uc_stack = curthread->sigstk;
ucp->uc_stack.ss_flags = (curthread->sigstk.ss_flags & SS_DISABLE)
? SS_DISABLE : ((onstack) ? SS_ONSTACK : 0);
if (curthread->oldsigmask) {
ucp->uc_sigmask = *(curthread->oldsigmask);
curthread->oldsigmask = NULL;
} else
ucp->uc_sigmask = sigmask;
shi.sigfunc = sigfunc;
shi.sig = sig;
shi.sa_flags = sa_flags;
shi.info = info;
shi.ucp = ucp;
if ((curthread->sigstk.ss_flags & SS_DISABLE) == 0) {
/* Deliver signal on alternative stack */
if (sa_flags & SA_ONSTACK && !onstack)
handle_signal_altstack(curthread, &shi);
else
handle_signal(curthread, &shi);
} else {
handle_signal(curthread, &shi);
}
_kse_critical_enter();
/* Don't trust after critical leave/enter */
curkse = _get_curkse();
/*
* Restore the thread's signal mask.
*/
curthread->sigmask = ucp->uc_sigmask;
SIG_CANTMASK(curthread->sigmask);
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
__sys_sigprocmask(SIG_SETMASK, &ucp->uc_sigmask, NULL);
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
DBG_MSG("Got signal %d, handler returned %p\n", sig, curthread);
}
static void
handle_signal(struct pthread *curthread, struct sighandle_info *shi)
{
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
if (((__sighandler_t *)shi->sigfunc != SIG_DFL) &&
((__sighandler_t *)shi->sigfunc != SIG_IGN)) {
if ((shi->sa_flags & SA_SIGINFO) != 0 || shi->info == NULL)
(*(shi->sigfunc))(shi->sig, shi->info, shi->ucp);
else {
((ohandler)(*shi->sigfunc))(
shi->sig, shi->info->si_code,
(struct sigcontext *)shi->ucp,
shi->info->si_addr,
(__sighandler_t *)shi->sigfunc);
}
} else {
if ((__sighandler_t *)shi->sigfunc == SIG_DFL) {
if (sigprop(shi->sig) & SA_KILL) {
if (_kse_isthreaded())
kse_thr_interrupt(NULL,
KSE_INTR_SIGEXIT, shi->sig);
else
kill(getpid(), shi->sig);
}
#ifdef NOTYET
else if (sigprop(shi->sig) & SA_STOP)
kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP,
shi->sig);
#endif
}
}
}
static void
handle_signal_wrapper(struct pthread *curthread, ucontext_t *ret_uc,
struct sighandle_info *shi)
{
shi->ucp->uc_stack.ss_flags = SS_ONSTACK;
handle_signal(curthread, shi);
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
setcontext(ret_uc);
else {
/* Work around for ia64, THR_SETCONTEXT does not work */
_kse_critical_enter();
curthread->tcb->tcb_tmbx.tm_context = *ret_uc;
_thread_switch(curthread->kse->k_kcb, curthread->tcb, 1);
/* THR_SETCONTEXT */
}
}
/*
* Jump to stack set by sigaltstack before invoking signal handler
*/
static void
handle_signal_altstack(struct pthread *curthread, struct sighandle_info *shi)
{
volatile int once;
ucontext_t uc1, *uc2;
THR_ASSERT(_kse_in_critical(), "Not in critical");
once = 0;
THR_GETCONTEXT(&uc1);
if (once == 0) {
once = 1;
/* XXX
* We are still in critical region, it is safe to operate thread
* context
*/
uc2 = &curthread->tcb->tcb_tmbx.tm_context;
uc2->uc_stack = curthread->sigstk;
makecontext(uc2, (void (*)(void))handle_signal_wrapper,
3, curthread, &uc1, shi);
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
setcontext(uc2);
else {
_thread_switch(curthread->kse->k_kcb, curthread->tcb, 1);
/* THR_SETCONTEXT(uc2); */
}
}
}
int
_thr_getprocsig(int sig, siginfo_t *siginfo)
{
kse_critical_t crit;
struct kse *curkse;
int ret;
DBG_MSG(">>> _thr_getprocsig\n");
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
ret = _thr_getprocsig_unlocked(sig, siginfo);
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
_kse_critical_leave(crit);
DBG_MSG("<<< _thr_getprocsig\n");
return (ret);
}
int
_thr_getprocsig_unlocked(int sig, siginfo_t *siginfo)
{
sigset_t sigset;
struct timespec ts;
/* try to retrieve signal from kernel */
SIGEMPTYSET(sigset);
SIGADDSET(sigset, sig);
ts.tv_sec = 0;
ts.tv_nsec = 0;
SIGDELSET(_thr_proc_sigpending, sig);
if (__sys_sigtimedwait(&sigset, siginfo, &ts) > 0)
return (sig);
return (0);
}
#ifndef SYSTEM_SCOPE_ONLY
/*
* 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)
{
struct kse_mailbox *kmbx = NULL;
struct pthread *pthread;
struct pthread *suspended_thread, *signaled_thread;
__siginfohandler_t *sigfunc;
siginfo_t si;
DBG_MSG("Looking for thread to handle signal %d\n", sig);
/*
* 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) {
if (pthread == _thr_sig_daemon)
continue;
/* Signal delivering to bound thread is done by kernel */
if (pthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
continue;
/* Take the scheduling lock. */
KSE_SCHED_LOCK(curkse, pthread->kseg);
if ((pthread->state == PS_DEAD) ||
(pthread->state == PS_DEADLOCK) ||
THR_IS_EXITING(pthread) ||
THR_IS_SUSPENDED(pthread)) {
; /* Skip this thread. */
} else if (pthread->state == PS_SIGWAIT &&
SIGISMEMBER(*(pthread->data.sigwait->waitset), sig)) {
/*
* retrieve signal from kernel, if it is job control
* signal, and sigaction is SIG_DFL, then we will
* be stopped in kernel, we hold lock here, but that
* does not matter, because that's job control, and
* whole process should be stopped.
*/
if (_thr_getprocsig(sig, &si)) {
DBG_MSG("Waking thread %p in sigwait"
" with signal %d\n", pthread, sig);
/* where to put siginfo ? */
*(pthread->data.sigwait->siginfo) = si;
kmbx = _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);
if (kmbx != NULL)
kse_wakeup(kmbx);
return (NULL);
} else if (!SIGISMEMBER(pthread->sigmask, sig)) {
sigfunc = _thread_sigact[sig - 1].sa_sigaction;
if ((__sighandler_t *)sigfunc == SIG_DFL) {
if (sigprop(sig) & SA_KILL) {
kse_thr_interrupt(NULL,
KSE_INTR_SIGEXIT, sig);
/* Never reach */
}
}
if (pthread->state == PS_SIGSUSPEND) {
if (suspended_thread == NULL) {
suspended_thread = pthread;
suspended_thread->refcount++;
}
} else if (signaled_thread == NULL) {
signaled_thread = pthread;
signaled_thread->refcount++;
}
}
KSE_SCHED_UNLOCK(curkse, pthread->kseg);
}
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
if (suspended_thread != NULL) {
pthread = suspended_thread;
if (signaled_thread)
_thr_ref_delete(NULL, signaled_thread);
} else if (signaled_thread) {
pthread = signaled_thread;
} else {
pthread = NULL;
}
return (pthread);
}
#endif /* ! SYSTEM_SCOPE_ONLY */
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)
{
int interrupted = curthread->interrupted;
int timeout = curthread->timeout;
siginfo_t siginfo;
int i;
kse_critical_t crit;
struct kse *curkse;
sigset_t sigmask;
DBG_MSG(">>> thr_sig_rundown (%p)\n", curthread);
/* Check the threads previous state: */
if ((psf != NULL) && (psf->psf_valid != 0)) {
/*
* 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->psf_state) {
case PS_COND_WAIT:
_cond_wait_backout(curthread);
psf->psf_state = PS_RUNNING;
break;
case PS_MUTEX_WAIT:
_mutex_lock_backout(curthread);
psf->psf_state = PS_RUNNING;
break;
case PS_RUNNING:
break;
default:
psf->psf_state = PS_RUNNING;
break;
}
/* XXX see comment in thr_sched_switch_unlocked */
curthread->critical_count--;
}
/*
* Lower the priority before calling the handler in case
* it never returns (longjmps back):
*/
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
curthread->active_priority &= ~THR_SIGNAL_PRIORITY;
SIGFILLSET(sigmask);
while (1) {
/*
* For bound thread, we mask all signals and get a fresh
* copy of signal mask from kernel
*/
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
__sys_sigprocmask(SIG_SETMASK, &sigmask,
&curthread->sigmask);
}
for (i = 1; i <= _SIG_MAXSIG; i++) {
if (SIGISMEMBER(curthread->sigmask, i))
continue;
if (SIGISMEMBER(curthread->sigpend, i)) {
SIGDELSET(curthread->sigpend, i);
siginfo = curthread->siginfo[i-1];
break;
}
if (!(curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
&& SIGISMEMBER(_thr_proc_sigpending, i)) {
if (_thr_getprocsig_unlocked(i, &siginfo))
break;
}
}
if (i <= _SIG_MAXSIG)
thr_sig_invoke_handler(curthread, i, &siginfo, ucp);
else {
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
__sys_sigprocmask(SIG_SETMASK,
&curthread->sigmask, NULL);
}
break;
}
}
if (psf != NULL && psf->psf_valid != 0)
thr_sigframe_restore(curthread, psf);
curkse = _get_curkse();
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
/* repost masked signal to kernel, it hardly happens in real world */
if ((curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) &&
!SIGISEMPTY(curthread->sigpend)) { /* dirty read */
__sys_sigprocmask(SIG_SETMASK, &sigmask, &curthread->sigmask);
for (i = 1; i <= _SIG_MAXSIG; ++i) {
if (SIGISMEMBER(curthread->sigpend, i)) {
SIGDELSET(curthread->sigpend, i);
if (!_kse_isthreaded())
kill(getpid(), i);
else
kse_thr_interrupt(
&curthread->tcb->tcb_tmbx,
KSE_INTR_SENDSIG,
i);
}
}
__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
}
curthread->interrupted = interrupted;
curthread->timeout = timeout;
DBG_MSG("<<< thr_sig_rundown (%p)\n", 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)
{
ucontext_t uc;
volatile int once;
int errsave;
if (THR_IN_CRITICAL(curthread))
return;
errsave = errno;
once = 0;
THR_GETCONTEXT(&uc);
if (once == 0) {
once = 1;
curthread->check_pending = 0;
_thr_sig_rundown(curthread, &uc, NULL);
}
errno = errsave;
}
#ifndef SYSTEM_SCOPE_ONLY
/*
* 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;
case SIGCONT:
KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
SIGDELSET(_thr_proc_sigpending, SIGTSTP);
SIGDELSET(_thr_proc_sigpending, SIGTTIN);
SIGDELSET(_thr_proc_sigpending, SIGTTOU);
KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
default:
break;
}
}
#endif /* ! SYSTEM_SCOPE_ONLY */
/*
* 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.
*/
struct kse_mailbox *
_thr_sig_add(struct pthread *pthread, int sig, siginfo_t *info)
{
siginfo_t siginfo;
struct kse *curkse;
struct kse_mailbox *kmbx = NULL;
struct pthread *curthread = _get_curthread();
int restart;
int suppress_handler = 0;
int fromproc = 0;
__sighandler_t *sigfunc;
DBG_MSG(">>> _thr_sig_add %p (%d)\n", pthread, sig);
curkse = _get_curkse();
restart = _thread_sigact[sig - 1].sa_flags & SA_RESTART;
sigfunc = _thread_sigact[sig - 1].sa_handler;
fromproc = (curthread == _thr_sig_daemon);
if (pthread->state == PS_DEAD || pthread->state == PS_DEADLOCK ||
pthread->state == PS_STATE_MAX)
return (NULL); /* return false */
if ((pthread->attr.flags & PTHREAD_SCOPE_SYSTEM) &&
(curthread != pthread)) {
PANIC("Please use _thr_send_sig for bound thread");
return (NULL);
}
if (pthread->curframe == NULL ||
(pthread->state != PS_SIGWAIT &&
SIGISMEMBER(pthread->sigmask, sig)) ||
THR_IN_CRITICAL(pthread)) {
/* thread is running or signal was being masked */
if (!fromproc) {
SIGADDSET(pthread->sigpend, sig);
if (info == NULL)
build_siginfo(&pthread->siginfo[sig-1], sig);
else if (info != &pthread->siginfo[sig-1])
memcpy(&pthread->siginfo[sig-1], info,
sizeof(*info));
} else {
if (!_thr_getprocsig(sig, &pthread->siginfo[sig-1]))
return (NULL);
SIGADDSET(pthread->sigpend, sig);
}
if (!SIGISMEMBER(pthread->sigmask, sig)) {
/* A quick path to exit process */
if (sigfunc == SIG_DFL && sigprop(sig) & SA_KILL) {
kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
/* Never reach */
}
pthread->check_pending = 1;
if (!(pthread->attr.flags & PTHREAD_SCOPE_SYSTEM) &&
(pthread->blocked != 0) &&
!THR_IN_CRITICAL(pthread))
kse_thr_interrupt(&pthread->tcb->tcb_tmbx,
restart ? KSE_INTR_RESTART : KSE_INTR_INTERRUPT, 0);
}
}
else {
/* if process signal not exists, just return */
if (fromproc) {
if (!_thr_getprocsig(sig, &siginfo))
return (NULL);
info = &siginfo;
}
if (pthread->state != PS_SIGWAIT && sigfunc == SIG_DFL &&
(sigprop(sig) & SA_KILL)) {
kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
/* Never reach */
}
/*
* Process according to thread state:
*/
switch (pthread->state) {
case PS_DEAD:
case PS_DEADLOCK:
case PS_STATE_MAX:
return (NULL); /* XXX return false */
case PS_LOCKWAIT:
case PS_SUSPENDED:
/*
* You can't call a signal handler for threads in these
* states.
*/
suppress_handler = 1;
break;
case PS_RUNNING:
if ((pthread->flags & THR_FLAGS_IN_RUNQ)) {
THR_RUNQ_REMOVE(pthread);
pthread->active_priority |= THR_SIGNAL_PRIORITY;
THR_RUNQ_INSERT_TAIL(pthread);
} else {
/* Possible not in RUNQ and has curframe ? */
pthread->active_priority |= THR_SIGNAL_PRIORITY;
}
suppress_handler = 1;
break;
/*
* States which cannot be interrupted but still require the
* signal handler to run:
*/
case PS_COND_WAIT:
case PS_MUTEX_WAIT:
break;
case PS_SLEEP_WAIT:
/*
* Unmasked signals always cause sleep to terminate
* early regardless of SA_RESTART:
*/
pthread->interrupted = 1;
break;
case PS_JOIN:
break;
case PS_SIGSUSPEND:
pthread->interrupted = 1;
break;
case PS_SIGWAIT:
if (info == NULL)
build_siginfo(&pthread->siginfo[sig-1], sig);
else if (info != &pthread->siginfo[sig-1])
memcpy(&pthread->siginfo[sig-1], info,
sizeof(*info));
/*
* The signal handler is not called for threads in
* SIGWAIT.
*/
suppress_handler = 1;
/* Wake up the thread if the signal is not blocked. */
if (SIGISMEMBER(*(pthread->data.sigwait->waitset), sig)) {
/* Return the signal number: */
*(pthread->data.sigwait->siginfo) = pthread->siginfo[sig-1];
/* Make the thread runnable: */
kmbx = _thr_setrunnable_unlocked(pthread);
} else {
/* Increment the pending signal count. */
SIGADDSET(pthread->sigpend, sig);
if (!SIGISMEMBER(pthread->sigmask, sig)) {
if (sigfunc == SIG_DFL &&
sigprop(sig) & SA_KILL) {
kse_thr_interrupt(NULL,
KSE_INTR_SIGEXIT,
sig);
/* Never reach */
}
pthread->check_pending = 1;
pthread->interrupted = 1;
kmbx = _thr_setrunnable_unlocked(pthread);
}
}
return (kmbx);
}
SIGADDSET(pthread->sigpend, sig);
if (info == NULL)
build_siginfo(&pthread->siginfo[sig-1], sig);
else if (info != &pthread->siginfo[sig-1])
memcpy(&pthread->siginfo[sig-1], info, sizeof(*info));
if (suppress_handler == 0) {
/*
* Setup a signal frame and save the current threads
* state:
*/
thr_sigframe_add(pthread);
if (pthread->flags & THR_FLAGS_IN_RUNQ)
THR_RUNQ_REMOVE(pthread);
pthread->active_priority |= THR_SIGNAL_PRIORITY;
kmbx = _thr_setrunnable_unlocked(pthread);
} else {
pthread->check_pending = 1;
}
}
return (kmbx);
}
/*
* Send a signal to a specific thread (ala pthread_kill):
*/
void
_thr_sig_send(struct pthread *pthread, int sig)
{
struct pthread *curthread = _get_curthread();
struct kse_mailbox *kmbx;
if (pthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
kse_thr_interrupt(&pthread->tcb->tcb_tmbx, KSE_INTR_SENDSIG, sig);
return;
}
/* Lock the scheduling queue of the target thread. */
THR_SCHED_LOCK(curthread, pthread);
if (_thread_sigact[sig - 1].sa_handler != SIG_IGN) {
kmbx = _thr_sig_add(pthread, sig, NULL);
THR_SCHED_UNLOCK(curthread, pthread);
if (kmbx != NULL)
kse_wakeup(kmbx);
/* XXX
* If thread sent signal to itself, check signals now.
* It is not really needed, _kse_critical_leave should
* have already checked signals.
*/
if (pthread == curthread && curthread->check_pending)
_thr_sig_check_pending(curthread);
} else {
THR_SCHED_UNLOCK(curthread, pthread);
}
}
static void
thr_sigframe_add(struct pthread *thread)
{
if (thread->curframe == NULL)
PANIC("Thread doesn't have signal frame ");
if (thread->curframe->psf_valid == 0) {
thread->curframe->psf_valid = 1;
/*
* 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);
}
}
static void
thr_sigframe_restore(struct pthread *thread, struct pthread_sigframe *psf)
{
if (psf->psf_valid == 0)
PANIC("invalid pthread_sigframe\n");
thread->flags = psf->psf_flags;
thread->interrupted = psf->psf_interrupted;
thread->timeout = psf->psf_timeout;
thread->state = psf->psf_state;
thread->data = psf->psf_wait_data;
thread->wakeup_time = psf->psf_wakeup_time;
}
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 | THR_FLAGS_IN_TDLIST);
psf->psf_interrupted = thread->interrupted;
psf->psf_timeout = thread->timeout;
psf->psf_state = thread->state;
psf->psf_wait_data = thread->data;
psf->psf_wakeup_time = thread->wakeup_time;
}
void
_thr_signal_init(void)
{
struct sigaction act;
__siginfohandler_t *sigfunc;
int i;
sigset_t sigset;
SIGFILLSET(sigset);
__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
/* Enter a loop to get the existing signal status: */
for (i = 1; i <= _SIG_MAXSIG; i++) {
/* Check for signals which cannot be trapped: */
if (i == SIGKILL || i == SIGSTOP) {
}
/* Get the signal handler details: */
else if (__sys_sigaction(i, NULL,
&_thread_sigact[i - 1]) != 0) {
/*
* Abort this process if signal
* initialisation fails:
*/
PANIC("Cannot read signal handler info");
}
/* Intall wrapper if handler was set */
sigfunc = _thread_sigact[i - 1].sa_sigaction;
if (((__sighandler_t *)sigfunc) != SIG_DFL &&
((__sighandler_t *)sigfunc) != SIG_IGN) {
act = _thread_sigact[i - 1];
act.sa_flags |= SA_SIGINFO;
act.sa_sigaction =
(__siginfohandler_t *)_thr_sig_handler;
__sys_sigaction(i, &act, NULL);
}
}
/*
* Install the signal handler for SIGINFO. It isn't
* really needed, but it is nice to have for debugging
* purposes.
*/
_thread_sigact[SIGINFO - 1].sa_flags = SA_SIGINFO | SA_RESTART;
SIGEMPTYSET(act.sa_mask);
act.sa_flags = SA_SIGINFO | SA_RESTART;
act.sa_sigaction = (__siginfohandler_t *)&_thr_sig_handler;
if (__sys_sigaction(SIGINFO, &act, NULL) != 0) {
__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
/*
* Abort this process if signal initialisation fails:
*/
PANIC("Cannot initialize signal handler");
}
__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
__sys_sigaltstack(NULL, &_thr_initial->sigstk);
}
void
_thr_signal_deinit(void)
{
int i;
struct pthread *curthread = _get_curthread();
/* Enter a loop to get the existing signal status: */
for (i = 1; i <= _SIG_MAXSIG; i++) {
/* Check for signals which cannot be trapped: */
if (i == SIGKILL || i == SIGSTOP) {
}
/* Set the signal handler details: */
else if (__sys_sigaction(i, &_thread_sigact[i - 1],
NULL) != 0) {
/*
* Abort this process if signal
* initialisation fails:
*/
PANIC("Cannot set signal handler info");
}
}
__sys_sigaltstack(&curthread->sigstk, NULL);
}
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