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5edadff94d
freebsd-nq/sys/kern/kern_sig.c
John Baldwin 5edadff94d - Remove garbage SIGSETOR() that snuck into struct sigpending_args 
definition.
- Use the proper constant for the last arg to kern_sigaction() in osigvec()
  instead of a magic value.
2003-04-17 22:06:43 +00:00

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/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
* $FreeBSD$
*/
#include "opt_compat.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/event.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/acct.h>
#include <sys/fcntl.h>
#include <sys/condvar.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/wait.h>
#include <sys/ktr.h>
#include <sys/ktrace.h>
#include <sys/resourcevar.h>
#include <sys/smp.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/syslog.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <machine/cpu.h>
#if defined (__alpha__) && !defined(COMPAT_43)
#error "You *really* need COMPAT_43 on the alpha for longjmp(3)"
#endif
#define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
static int coredump(struct thread *);
static char *expand_name(const char *, uid_t, pid_t);
static int killpg1(struct thread *td, int sig, int pgid, int all);
static int sigprop(int sig);
static void stop(struct proc *);
static void tdsigwakeup(struct thread *td, int sig, sig_t action);
static int filt_sigattach(struct knote *kn);
static void filt_sigdetach(struct knote *kn);
static int filt_signal(struct knote *kn, long hint);
static struct thread *sigtd(struct proc *p, int sig, int prop);
static int do_sigprocmask(struct thread *td, int how,
sigset_t *set, sigset_t *oset, int old);
static int kern_sigtimedwait(struct thread *td, sigset_t set,
siginfo_t *info, struct timespec *timeout);
struct filterops sig_filtops =
{ 0, filt_sigattach, filt_sigdetach, filt_signal };
static int kern_logsigexit = 1;
SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
&kern_logsigexit, 0,
"Log processes quitting on abnormal signals to syslog(3)");
/*
* Policy -- Can ucred cr1 send SIGIO to process cr2?
* Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
* in the right situations.
*/
#define CANSIGIO(cr1, cr2) \
((cr1)->cr_uid == 0 || \
(cr1)->cr_ruid == (cr2)->cr_ruid || \
(cr1)->cr_uid == (cr2)->cr_ruid || \
(cr1)->cr_ruid == (cr2)->cr_uid || \
(cr1)->cr_uid == (cr2)->cr_uid)
int sugid_coredump;
SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
&sugid_coredump, 0, "Enable coredumping set user/group ID processes");
static int do_coredump = 1;
SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
&do_coredump, 0, "Enable/Disable coredumps");
/*
* Signal properties and actions.
* The array below categorizes the signals and their default actions
* according to the following properties:
*/
#define SA_KILL 0x01 /* terminates process by default */
#define SA_CORE 0x02 /* ditto and coredumps */
#define SA_STOP 0x04 /* suspend process */
#define SA_TTYSTOP 0x08 /* ditto, from tty */
#define SA_IGNORE 0x10 /* ignore by default */
#define SA_CONT 0x20 /* continue if suspended */
#define SA_CANTMASK 0x40 /* non-maskable, catchable */
#define SA_PROC 0x80 /* deliverable to any thread */
static int sigproptbl[NSIG] = {
SA_KILL|SA_PROC, /* SIGHUP */
SA_KILL|SA_PROC, /* SIGINT */
SA_KILL|SA_CORE|SA_PROC, /* SIGQUIT */
SA_KILL|SA_CORE, /* SIGILL */
SA_KILL|SA_CORE, /* SIGTRAP */
SA_KILL|SA_CORE, /* SIGABRT */
SA_KILL|SA_CORE|SA_PROC, /* SIGEMT */
SA_KILL|SA_CORE, /* SIGFPE */
SA_KILL|SA_PROC, /* SIGKILL */
SA_KILL|SA_CORE, /* SIGBUS */
SA_KILL|SA_CORE, /* SIGSEGV */
SA_KILL|SA_CORE, /* SIGSYS */
SA_KILL|SA_PROC, /* SIGPIPE */
SA_KILL|SA_PROC, /* SIGALRM */
SA_KILL|SA_PROC, /* SIGTERM */
SA_IGNORE|SA_PROC, /* SIGURG */
SA_STOP|SA_PROC, /* SIGSTOP */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTSTP */
SA_IGNORE|SA_CONT|SA_PROC, /* SIGCONT */
SA_IGNORE|SA_PROC, /* SIGCHLD */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTIN */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTOU */
SA_IGNORE|SA_PROC, /* SIGIO */
SA_KILL, /* SIGXCPU */
SA_KILL, /* SIGXFSZ */
SA_KILL|SA_PROC, /* SIGVTALRM */
SA_KILL|SA_PROC, /* SIGPROF */
SA_IGNORE|SA_PROC, /* SIGWINCH */
SA_IGNORE|SA_PROC, /* SIGINFO */
SA_KILL|SA_PROC, /* SIGUSR1 */
SA_KILL|SA_PROC, /* SIGUSR2 */
};
/*
* Determine signal that should be delivered to process p, the current
* process, 0 if none. If there is a pending stop signal with default
* action, the process stops in issignal().
* XXXKSE the check for a pending stop is not done under KSE
*
* MP SAFE.
*/
int
cursig(struct thread *td)
{
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
mtx_assert(&sched_lock, MA_NOTOWNED);
return (SIGPENDING(td) ? issignal(td) : 0);
}
/*
* Arrange for ast() to handle unmasked pending signals on return to user
* mode. This must be called whenever a signal is added to td_siglist or
* unmasked in td_sigmask.
*/
void
signotify(struct thread *td)
{
struct proc *p;
sigset_t set;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
/*
* If our mask changed we may have to move signal that were
* previously masked by all threads to our siglist.
*/
set = p->p_siglist;
SIGSETNAND(set, td->td_sigmask);
SIGSETNAND(p->p_siglist, set);
SIGSETOR(td->td_siglist, set);
mtx_lock_spin(&sched_lock);
if (SIGPENDING(td))
td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
mtx_unlock_spin(&sched_lock);
}
static __inline int
sigprop(int sig)
{
if (sig > 0 && sig < NSIG)
return (sigproptbl[_SIG_IDX(sig)]);
return (0);
}
int
sig_ffs(sigset_t *set)
{
int i;
for (i = 0; i < _SIG_WORDS; i++)
if (set->__bits[i])
return (ffs(set->__bits[i]) + (i * 32));
return (0);
}
/*
* kern_sigaction
* sigaction
* freebsd4_sigaction
* osigaction
*/
int
kern_sigaction(td, sig, act, oact, flags)
struct thread *td;
register int sig;
struct sigaction *act, *oact;
int flags;
{
register struct sigacts *ps;
struct thread *td0;
struct proc *p = td->td_proc;
if (!_SIG_VALID(sig))
return (EINVAL);
PROC_LOCK(p);
ps = p->p_sigacts;
if (oact) {
oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
oact->sa_flags = 0;
if (SIGISMEMBER(ps->ps_sigonstack, sig))
oact->sa_flags |= SA_ONSTACK;
if (!SIGISMEMBER(ps->ps_sigintr, sig))
oact->sa_flags |= SA_RESTART;
if (SIGISMEMBER(ps->ps_sigreset, sig))
oact->sa_flags |= SA_RESETHAND;
if (SIGISMEMBER(ps->ps_signodefer, sig))
oact->sa_flags |= SA_NODEFER;
if (SIGISMEMBER(ps->ps_siginfo, sig))
oact->sa_flags |= SA_SIGINFO;
if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP)
oact->sa_flags |= SA_NOCLDSTOP;
if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT)
oact->sa_flags |= SA_NOCLDWAIT;
}
if (act) {
if ((sig == SIGKILL || sig == SIGSTOP) &&
act->sa_handler != SIG_DFL) {
PROC_UNLOCK(p);
return (EINVAL);
}
/*
* Change setting atomically.
*/
ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
if (act->sa_flags & SA_SIGINFO) {
ps->ps_sigact[_SIG_IDX(sig)] =
(__sighandler_t *)act->sa_sigaction;
SIGADDSET(ps->ps_siginfo, sig);
} else {
ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
SIGDELSET(ps->ps_siginfo, sig);
}
if (!(act->sa_flags & SA_RESTART))
SIGADDSET(ps->ps_sigintr, sig);
else
SIGDELSET(ps->ps_sigintr, sig);
if (act->sa_flags & SA_ONSTACK)
SIGADDSET(ps->ps_sigonstack, sig);
else
SIGDELSET(ps->ps_sigonstack, sig);
if (act->sa_flags & SA_RESETHAND)
SIGADDSET(ps->ps_sigreset, sig);
else
SIGDELSET(ps->ps_sigreset, sig);
if (act->sa_flags & SA_NODEFER)
SIGADDSET(ps->ps_signodefer, sig);
else
SIGDELSET(ps->ps_signodefer, sig);
#ifdef COMPAT_SUNOS
if (act->sa_flags & SA_USERTRAMP)
SIGADDSET(ps->ps_usertramp, sig);
else
SIGDELSET(ps->ps_usertramp, sig);
#endif
if (sig == SIGCHLD) {
if (act->sa_flags & SA_NOCLDSTOP)
p->p_procsig->ps_flag |= PS_NOCLDSTOP;
else
p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
if (act->sa_flags & SA_NOCLDWAIT) {
/*
* Paranoia: since SA_NOCLDWAIT is implemented
* by reparenting the dying child to PID 1 (and
* trust it to reap the zombie), PID 1 itself
* is forbidden to set SA_NOCLDWAIT.
*/
if (p->p_pid == 1)
p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
else
p->p_procsig->ps_flag |= PS_NOCLDWAIT;
} else
p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
p->p_procsig->ps_flag |= PS_CLDSIGIGN;
else
p->p_procsig->ps_flag &= ~PS_CLDSIGIGN;
}
/*
* Set bit in p_sigignore for signals that are set to SIG_IGN,
* and for signals set to SIG_DFL where the default is to
* ignore. However, don't put SIGCONT in p_sigignore, as we
* have to restart the process.
*/
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
(sigprop(sig) & SA_IGNORE &&
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
/* never to be seen again */
SIGDELSET(p->p_siglist, sig);
FOREACH_THREAD_IN_PROC(p, td0)
SIGDELSET(td0->td_siglist, sig);
if (sig != SIGCONT)
/* easier in psignal */
SIGADDSET(p->p_sigignore, sig);
SIGDELSET(p->p_sigcatch, sig);
} else {
SIGDELSET(p->p_sigignore, sig);
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
SIGDELSET(p->p_sigcatch, sig);
else
SIGADDSET(p->p_sigcatch, sig);
}
#ifdef COMPAT_FREEBSD4
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
(flags & KSA_FREEBSD4) == 0)
SIGDELSET(ps->ps_freebsd4, sig);
else
SIGADDSET(ps->ps_freebsd4, sig);
#endif
#ifdef COMPAT_43
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
(flags & KSA_OSIGSET) == 0)
SIGDELSET(ps->ps_osigset, sig);
else
SIGADDSET(ps->ps_osigset, sig);
#endif
}
PROC_UNLOCK(p);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct sigaction_args {
int sig;
struct sigaction *act;
struct sigaction *oact;
};
#endif
/*
* MPSAFE
*/
int
sigaction(td, uap)
struct thread *td;
register struct sigaction_args *uap;
{
struct sigaction act, oact;
register struct sigaction *actp, *oactp;
int error;
actp = (uap->act != NULL) ? &act : NULL;
oactp = (uap->oact != NULL) ? &oact : NULL;
if (actp) {
error = copyin(uap->act, actp, sizeof(act));
if (error)
return (error);
}
mtx_lock(&Giant);
error = kern_sigaction(td, uap->sig, actp, oactp, 0);
mtx_unlock(&Giant);
if (oactp && !error) {
error = copyout(oactp, uap->oact, sizeof(oact));
}
return (error);
}
#ifdef COMPAT_FREEBSD4
#ifndef _SYS_SYSPROTO_H_
struct freebsd4_sigaction_args {
int sig;
struct sigaction *act;
struct sigaction *oact;
};
#endif
/*
* MPSAFE
*/
int
freebsd4_sigaction(td, uap)
struct thread *td;
register struct freebsd4_sigaction_args *uap;
{
struct sigaction act, oact;
register struct sigaction *actp, *oactp;
int error;
actp = (uap->act != NULL) ? &act : NULL;
oactp = (uap->oact != NULL) ? &oact : NULL;
if (actp) {
error = copyin(uap->act, actp, sizeof(act));
if (error)
return (error);
}
mtx_lock(&Giant);
error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
mtx_unlock(&Giant);
if (oactp && !error) {
error = copyout(oactp, uap->oact, sizeof(oact));
}
return (error);
}
#endif /* COMAPT_FREEBSD4 */
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigaction_args {
int signum;
struct osigaction *nsa;
struct osigaction *osa;
};
#endif
/*
* MPSAFE
*/
int
osigaction(td, uap)
struct thread *td;
register struct osigaction_args *uap;
{
struct osigaction sa;
struct sigaction nsa, osa;
register struct sigaction *nsap, *osap;
int error;
if (uap->signum <= 0 || uap->signum >= ONSIG)
return (EINVAL);
nsap = (uap->nsa != NULL) ? &nsa : NULL;
osap = (uap->osa != NULL) ? &osa : NULL;
if (nsap) {
error = copyin(uap->nsa, &sa, sizeof(sa));
if (error)
return (error);
nsap->sa_handler = sa.sa_handler;
nsap->sa_flags = sa.sa_flags;
OSIG2SIG(sa.sa_mask, nsap->sa_mask);
}
mtx_lock(&Giant);
error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
mtx_unlock(&Giant);
if (osap && !error) {
sa.sa_handler = osap->sa_handler;
sa.sa_flags = osap->sa_flags;
SIG2OSIG(osap->sa_mask, sa.sa_mask);
error = copyout(&sa, uap->osa, sizeof(sa));
}
return (error);
}
#if !defined(__i386__) && !defined(__alpha__)
/* Avoid replicating the same stub everywhere */
int
osigreturn(td, uap)
struct thread *td;
struct osigreturn_args *uap;
{
return (nosys(td, (struct nosys_args *)uap));
}
#endif
#endif /* COMPAT_43 */
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(p)
struct proc *p;
{
register int i;
PROC_LOCK(p);
for (i = 1; i <= NSIG; i++)
if (sigprop(i) & SA_IGNORE && i != SIGCONT)
SIGADDSET(p->p_sigignore, i);
PROC_UNLOCK(p);
}
/*
* Reset signals for an exec of the specified process.
*/
void
execsigs(p)
register struct proc *p;
{
register struct sigacts *ps;
register int sig;
/*
* Reset caught signals. Held signals remain held
* through td_sigmask (unless they were caught,
* and are now ignored by default).
*/
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
while (SIGNOTEMPTY(p->p_sigcatch)) {
sig = sig_ffs(&p->p_sigcatch);
SIGDELSET(p->p_sigcatch, sig);
if (sigprop(sig) & SA_IGNORE) {
if (sig != SIGCONT)
SIGADDSET(p->p_sigignore, sig);
SIGDELSET(p->p_siglist, sig);
/*
* There is only one thread at this point.
*/
SIGDELSET(FIRST_THREAD_IN_PROC(p)->td_siglist, sig);
}
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
/*
* Clear out the td's sigmask. Normal processes use the proc sigmask.
*/
SIGEMPTYSET(FIRST_THREAD_IN_PROC(p)->td_sigmask);
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
p->p_sigstk.ss_flags = SS_DISABLE;
p->p_sigstk.ss_size = 0;
p->p_sigstk.ss_sp = 0;
p->p_flag &= ~P_ALTSTACK;
/*
* Reset no zombies if child dies flag as Solaris does.
*/
p->p_procsig->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
}
/*
* do_sigprocmask()
*
* Manipulate signal mask.
*/
static int
do_sigprocmask(td, how, set, oset, old)
struct thread *td;
int how;
sigset_t *set, *oset;
int old;
{
int error;
PROC_LOCK(td->td_proc);
if (oset != NULL)
*oset = td->td_sigmask;
error = 0;
if (set != NULL) {
switch (how) {
case SIG_BLOCK:
SIG_CANTMASK(*set);
SIGSETOR(td->td_sigmask, *set);
break;
case SIG_UNBLOCK:
SIGSETNAND(td->td_sigmask, *set);
signotify(td);
break;
case SIG_SETMASK:
SIG_CANTMASK(*set);
if (old)
SIGSETLO(td->td_sigmask, *set);
else
td->td_sigmask = *set;
signotify(td);
break;
default:
error = EINVAL;
break;
}
}
PROC_UNLOCK(td->td_proc);
return (error);
}
/*
* sigprocmask() - MP SAFE (XXXKSE not under KSE it isn't)
*/
#ifndef _SYS_SYSPROTO_H_
struct sigprocmask_args {
int how;
const sigset_t *set;
sigset_t *oset;
};
#endif
int
sigprocmask(td, uap)
register struct thread *td;
struct sigprocmask_args *uap;
{
sigset_t set, oset;
sigset_t *setp, *osetp;
int error;
setp = (uap->set != NULL) ? &set : NULL;
osetp = (uap->oset != NULL) ? &oset : NULL;
if (setp) {
error = copyin(uap->set, setp, sizeof(set));
if (error)
return (error);
}
error = do_sigprocmask(td, uap->how, setp, osetp, 0);
if (osetp && !error) {
error = copyout(osetp, uap->oset, sizeof(oset));
}
return (error);
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
/*
* osigprocmask() - MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct osigprocmask_args {
int how;
osigset_t mask;
};
#endif
int
osigprocmask(td, uap)
register struct thread *td;
struct osigprocmask_args *uap;
{
sigset_t set, oset;
int error;
OSIG2SIG(uap->mask, set);
error = do_sigprocmask(td, uap->how, &set, &oset, 1);
SIG2OSIG(oset, td->td_retval[0]);
return (error);
}
#endif /* COMPAT_43 */
#ifndef _SYS_SYSPROTO_H_
struct sigpending_args {
sigset_t *set;
};
#endif
/*
* MPSAFE
*/
int
sigwait(struct thread *td, struct sigwait_args *uap)
{
siginfo_t info;
sigset_t set;
int error;
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
error = kern_sigtimedwait(td, set, &info, NULL);
if (error)
return (error);
error = copyout(&info.si_signo, uap->sig, sizeof(info.si_signo));
/* Repost if we got an error. */
if (error && info.si_signo)
tdsignal(td, info.si_signo);
return (error);
}
/*
* MPSAFE
*/
int
sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
{
struct timespec ts;
struct timespec *timeout;
sigset_t set;
siginfo_t info;
int error;
if (uap->timeout) {
error = copyin(uap->timeout, &ts, sizeof(ts));
if (error)
return (error);
timeout = &ts;
} else
timeout = NULL;
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
error = kern_sigtimedwait(td, set, &info, timeout);
if (error)
return (error);
error = copyout(&info, uap->info, sizeof(info));
/* Repost if we got an error. */
if (error && info.si_signo)
tdsignal(td, info.si_signo);
return (error);
}
/*
* MPSAFE
*/
int
sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
{
siginfo_t info;
sigset_t set;
int error;
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
error = kern_sigtimedwait(td, set, &info, NULL);
if (error)
return (error);
error = copyout(&info, uap->info, sizeof(info));
/* Repost if we got an error. */
if (error && info.si_signo)
tdsignal(td, info.si_signo);
return (error);
}
static int
kern_sigtimedwait(struct thread *td, sigset_t set, siginfo_t *info,
struct timespec *timeout)
{
register struct sigacts *ps;
sigset_t oldmask;
struct proc *p;
int error;
int sig;
int hz;
p = td->td_proc;
error = 0;
sig = 0;
SIG_CANTMASK(set);
mtx_lock(&Giant);
PROC_LOCK(p);
ps = p->p_sigacts;
oldmask = td->td_sigmask;
td->td_sigmask = set;
signotify(td);
sig = cursig(td);
if (sig)
goto out;
/*
* POSIX says this must be checked after looking for pending
* signals.
*/
if (timeout) {
struct timeval tv;
if (timeout->tv_nsec > 1000000000) {
error = EINVAL;
goto out;
}
TIMESPEC_TO_TIMEVAL(&tv, timeout);
hz = tvtohz(&tv);
} else
hz = 0;
error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "pause", hz);
if (error == EINTR)
error = 0;
else if (error)
goto out;
sig = cursig(td);
out:
td->td_sigmask = oldmask;
if (sig) {
sig_t action;
action = ps->ps_sigact[_SIG_IDX(sig)];
#ifdef KTRACE
if (KTRPOINT(td, KTR_PSIG))
ktrpsig(sig, action, td->td_flags & TDF_OLDMASK ?
&td->td_oldsigmask : &td->td_sigmask, 0);
#endif
_STOPEVENT(p, S_SIG, sig);
if (action == SIG_DFL)
sigexit(td, sig);
/* NOTREACHED */
SIGDELSET(td->td_siglist, sig);
info->si_signo = sig;
info->si_code = 0;
}
PROC_UNLOCK(p);
mtx_unlock(&Giant);
return (error);
}
/*
* MPSAFE
*/
int
sigpending(td, uap)
struct thread *td;
struct sigpending_args *uap;
{
struct proc *p = td->td_proc;
sigset_t siglist;
PROC_LOCK(p);
siglist = p->p_siglist;
SIGSETOR(siglist, td->td_siglist);
PROC_UNLOCK(p);
return (copyout(&siglist, uap->set, sizeof(sigset_t)));
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigpending_args {
int dummy;
};
#endif
/*
* MPSAFE
*/
int
osigpending(td, uap)
struct thread *td;
struct osigpending_args *uap;
{
struct proc *p = td->td_proc;
sigset_t siglist;
PROC_LOCK(p);
siglist = p->p_siglist;
SIGSETOR(siglist, td->td_siglist);
SIG2OSIG(siglist, td->td_retval[0]);
PROC_UNLOCK(p);
return (0);
}
#endif /* COMPAT_43 */
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
/*
* Generalized interface signal handler, 4.3-compatible.
*/
#ifndef _SYS_SYSPROTO_H_
struct osigvec_args {
int signum;
struct sigvec *nsv;
struct sigvec *osv;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
osigvec(td, uap)
struct thread *td;
register struct osigvec_args *uap;
{
struct sigvec vec;
struct sigaction nsa, osa;
register struct sigaction *nsap, *osap;
int error;
if (uap->signum <= 0 || uap->signum >= ONSIG)
return (EINVAL);
nsap = (uap->nsv != NULL) ? &nsa : NULL;
osap = (uap->osv != NULL) ? &osa : NULL;
if (nsap) {
error = copyin(uap->nsv, &vec, sizeof(vec));
if (error)
return (error);
nsap->sa_handler = vec.sv_handler;
OSIG2SIG(vec.sv_mask, nsap->sa_mask);
nsap->sa_flags = vec.sv_flags;
nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
#ifdef COMPAT_SUNOS
nsap->sa_flags |= SA_USERTRAMP;
#endif
}
mtx_lock(&Giant);
error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
mtx_unlock(&Giant);
if (osap && !error) {
vec.sv_handler = osap->sa_handler;
SIG2OSIG(osap->sa_mask, vec.sv_mask);
vec.sv_flags = osap->sa_flags;
vec.sv_flags &= ~SA_NOCLDWAIT;
vec.sv_flags ^= SA_RESTART;
#ifdef COMPAT_SUNOS
vec.sv_flags &= ~SA_NOCLDSTOP;
#endif
error = copyout(&vec, uap->osv, sizeof(vec));
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct osigblock_args {
int mask;
};
#endif
/*
* MPSAFE
*/
int
osigblock(td, uap)
register struct thread *td;
struct osigblock_args *uap;
{
struct proc *p = td->td_proc;
sigset_t set;
OSIG2SIG(uap->mask, set);
SIG_CANTMASK(set);
mtx_lock(&Giant);
PROC_LOCK(p);
SIG2OSIG(td->td_sigmask, td->td_retval[0]);
SIGSETOR(td->td_sigmask, set);
PROC_UNLOCK(p);
mtx_unlock(&Giant);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct osigsetmask_args {
int mask;
};
#endif
/*
* MPSAFE
*/
int
osigsetmask(td, uap)
struct thread *td;
struct osigsetmask_args *uap;
{
struct proc *p = td->td_proc;
sigset_t set;
OSIG2SIG(uap->mask, set);
SIG_CANTMASK(set);
mtx_lock(&Giant);
PROC_LOCK(p);
SIG2OSIG(td->td_sigmask, td->td_retval[0]);
SIGSETLO(td->td_sigmask, set);
signotify(td);
PROC_UNLOCK(p);
mtx_unlock(&Giant);
return (0);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */
/*
* Suspend process until signal, providing mask to be set
* in the meantime. Note nonstandard calling convention:
* libc stub passes mask, not pointer, to save a copyin.
***** XXXKSE this doesn't make sense under KSE.
***** Do we suspend the thread or all threads in the process?
***** How do we suspend threads running NOW on another processor?
*/
#ifndef _SYS_SYSPROTO_H_
struct sigsuspend_args {
const sigset_t *sigmask;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
sigsuspend(td, uap)
struct thread *td;
struct sigsuspend_args *uap;
{
sigset_t mask;
int error;
error = copyin(uap->sigmask, &mask, sizeof(mask));
if (error)
return (error);
return (kern_sigsuspend(td, mask));
}
int
kern_sigsuspend(struct thread *td, sigset_t mask)
{
struct proc *p = td->td_proc;
register struct sigacts *ps;
/*
* When returning from sigsuspend, we want
* the old mask to be restored after the
* signal handler has finished. Thus, we
* save it here and mark the sigacts structure
* to indicate this.
*/
mtx_lock(&Giant);
PROC_LOCK(p);
ps = p->p_sigacts;
td->td_oldsigmask = td->td_sigmask;
mtx_lock_spin(&sched_lock);
td->td_flags |= TDF_OLDMASK;
mtx_unlock_spin(&sched_lock);
SIG_CANTMASK(mask);
td->td_sigmask = mask;
signotify(td);
while (msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "pause", 0) == 0)
/* void */;
PROC_UNLOCK(p);
mtx_unlock(&Giant);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigsuspend_args {
osigset_t mask;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
osigsuspend(td, uap)
struct thread *td;
struct osigsuspend_args *uap;
{
struct proc *p = td->td_proc;
sigset_t mask;
register struct sigacts *ps;
mtx_lock(&Giant);
PROC_LOCK(p);
ps = p->p_sigacts;
td->td_oldsigmask = td->td_sigmask;
mtx_lock_spin(&sched_lock);
td->td_flags |= TDF_OLDMASK;
mtx_unlock_spin(&sched_lock);
OSIG2SIG(uap->mask, mask);
SIG_CANTMASK(mask);
SIGSETLO(td->td_sigmask, mask);
signotify(td);
while (msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "opause", 0) == 0)
/* void */;
PROC_UNLOCK(p);
mtx_unlock(&Giant);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
#endif /* COMPAT_43 */
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
#ifndef _SYS_SYSPROTO_H_
struct osigstack_args {
struct sigstack *nss;
struct sigstack *oss;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
osigstack(td, uap)
struct thread *td;
register struct osigstack_args *uap;
{
struct proc *p = td->td_proc;
struct sigstack ss;
int error = 0;
mtx_lock(&Giant);
if (uap->oss != NULL) {
PROC_LOCK(p);
ss.ss_sp = p->p_sigstk.ss_sp;
ss.ss_onstack = sigonstack(cpu_getstack(td));
PROC_UNLOCK(p);
error = copyout(&ss, uap->oss, sizeof(struct sigstack));
if (error)
goto done2;
}
if (uap->nss != NULL) {
if ((error = copyin(uap->nss, &ss, sizeof(ss))) != 0)
goto done2;
PROC_LOCK(p);
p->p_sigstk.ss_sp = ss.ss_sp;
p->p_sigstk.ss_size = 0;
p->p_sigstk.ss_flags |= ss.ss_onstack & SS_ONSTACK;
p->p_flag |= P_ALTSTACK;
PROC_UNLOCK(p);
}
done2:
mtx_unlock(&Giant);
return (error);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */
#ifndef _SYS_SYSPROTO_H_
struct sigaltstack_args {
stack_t *ss;
stack_t *oss;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
sigaltstack(td, uap)
struct thread *td;
register struct sigaltstack_args *uap;
{
stack_t ss, oss;
int error;
if (uap->ss != NULL) {
error = copyin(uap->ss, &ss, sizeof(ss));
if (error)
return (error);
}
error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
(uap->oss != NULL) ? &oss : NULL);
if (error)
return (error);
if (uap->oss != NULL)
error = copyout(&oss, uap->oss, sizeof(stack_t));
return (error);
}
int
kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
{
struct proc *p = td->td_proc;
int oonstack;
int error = 0;
mtx_lock(&Giant);
oonstack = sigonstack(cpu_getstack(td));
if (oss != NULL) {
PROC_LOCK(p);
*oss = p->p_sigstk;
oss->ss_flags = (p->p_flag & P_ALTSTACK)
? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
PROC_UNLOCK(p);
}
if (ss != NULL) {
if (oonstack) {
error = EPERM;
goto done2;
}
if ((ss->ss_flags & ~SS_DISABLE) != 0) {
error = EINVAL;
goto done2;
}
if (!(ss->ss_flags & SS_DISABLE)) {
if (ss->ss_size < p->p_sysent->sv_minsigstksz) {
error = ENOMEM;
goto done2;
}
PROC_LOCK(p);
p->p_sigstk = *ss;
p->p_flag |= P_ALTSTACK;
PROC_UNLOCK(p);
} else {
PROC_LOCK(p);
p->p_flag &= ~P_ALTSTACK;
PROC_UNLOCK(p);
}
}
done2:
mtx_unlock(&Giant);
return (error);
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
static int
killpg1(td, sig, pgid, all)
register struct thread *td;
int sig, pgid, all;
{
register struct proc *p;
struct pgrp *pgrp;
int nfound = 0;
if (all) {
/*
* broadcast
*/
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
PROC_LOCK(p);
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p == td->td_proc) {
PROC_UNLOCK(p);
continue;
}
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
}
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
} else {
sx_slock(&proctree_lock);
if (pgid == 0) {
/*
* zero pgid means send to my process group.
*/
pgrp = td->td_proc->p_pgrp;
PGRP_LOCK(pgrp);
} else {
pgrp = pgfind(pgid);
if (pgrp == NULL) {
sx_sunlock(&proctree_lock);
return (ESRCH);
}
}
sx_sunlock(&proctree_lock);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM) {
PROC_UNLOCK(p);
continue;
}
if (p->p_state == PRS_ZOMBIE) {
PROC_UNLOCK(p);
continue;
}
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
}
PROC_UNLOCK(p);
}
PGRP_UNLOCK(pgrp);
}
return (nfound ? 0 : ESRCH);
}
#ifndef _SYS_SYSPROTO_H_
struct kill_args {
int pid;
int signum;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
kill(td, uap)
register struct thread *td;
register struct kill_args *uap;
{
register struct proc *p;
int error = 0;
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
mtx_lock(&Giant);
if (uap->pid > 0) {
/* kill single process */
if ((p = pfind(uap->pid)) == NULL) {
error = ESRCH;
} else if ((error = p_cansignal(td, p, uap->signum)) != 0) {
PROC_UNLOCK(p);
} else {
if (uap->signum)
psignal(p, uap->signum);
PROC_UNLOCK(p);
error = 0;
}
} else {
switch (uap->pid) {
case -1: /* broadcast signal */
error = killpg1(td, uap->signum, 0, 1);
break;
case 0: /* signal own process group */
error = killpg1(td, uap->signum, 0, 0);
break;
default: /* negative explicit process group */
error = killpg1(td, uap->signum, -uap->pid, 0);
break;
}
}
mtx_unlock(&Giant);
return(error);
}
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
#ifndef _SYS_SYSPROTO_H_
struct okillpg_args {
int pgid;
int signum;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
okillpg(td, uap)
struct thread *td;
register struct okillpg_args *uap;
{
int error;
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
mtx_lock(&Giant);
error = killpg1(td, uap->signum, uap->pgid, 0);
mtx_unlock(&Giant);
return (error);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */
/*
* Send a signal to a process group.
*/
void
gsignal(pgid, sig)
int pgid, sig;
{
struct pgrp *pgrp;
if (pgid != 0) {
sx_slock(&proctree_lock);
pgrp = pgfind(pgid);
sx_sunlock(&proctree_lock);
if (pgrp != NULL) {
pgsignal(pgrp, sig, 0);
PGRP_UNLOCK(pgrp);
}
}
}
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(pgrp, sig, checkctty)
struct pgrp *pgrp;
int sig, checkctty;
{
register struct proc *p;
if (pgrp) {
PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (checkctty == 0 || p->p_flag & P_CONTROLT)
psignal(p, sig);
PROC_UNLOCK(p);
}
}
}
/*
* Send a signal caused by a trap to the current thread.
* If it will be caught immediately, deliver it with correct code.
* Otherwise, post it normally.
*
* MPSAFE
*/
void
trapsignal(struct thread *td, int sig, u_long code)
{
struct sigacts *ps;
struct proc *p;
p = td->td_proc;
PROC_LOCK(p);
ps = p->p_sigacts;
if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
!SIGISMEMBER(td->td_sigmask, sig)) {
p->p_stats->p_ru.ru_nsignals++;
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_PSIG))
ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
&td->td_sigmask, code);
#endif
(*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
&td->td_sigmask, code);
SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(td->td_sigmask, sig);
if (SIGISMEMBER(ps->ps_sigreset, sig)) {
/*
* See kern_sigaction() for origin of this code.
*/
SIGDELSET(p->p_sigcatch, sig);
if (sig != SIGCONT &&
sigprop(sig) & SA_IGNORE)
SIGADDSET(p->p_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
} else {
p->p_code = code; /* XXX for core dump/debugger */
p->p_sig = sig; /* XXX to verify code */
tdsignal(td, sig);
}
PROC_UNLOCK(p);
}
static struct thread *
sigtd(struct proc *p, int sig, int prop)
{
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
/*
* If we know the signal is bound for a specific thread then we
* assume that we are in that threads context. This is the case
* for SIGXCPU, SIGILL, etc. Otherwise someone did a kill() from
* userland and the real thread doesn't actually matter.
*/
if ((prop & SA_PROC) != 0 && curthread->td_proc == p)
return (curthread);
/*
* We should search for the first thread that is blocked in
* sigsuspend with this signal unmasked.
*/
/* XXX */
/*
* Find the first thread in the proc that doesn't have this signal
* masked.
*/
FOREACH_THREAD_IN_PROC(p, td)
if (!SIGISMEMBER(td->td_sigmask, sig))
return (td);
return (FIRST_THREAD_IN_PROC(p));
}
/*
* Send the signal to the process. If the signal has an action, the action
* is usually performed by the target process rather than the caller; we add
* the signal to the set of pending signals for the process.
*
* Exceptions:
* o When a stop signal is sent to a sleeping process that takes the
* default action, the process is stopped without awakening it.
* o SIGCONT restarts stopped processes (or puts them back to sleep)
* regardless of the signal action (eg, blocked or ignored).
*
* Other ignored signals are discarded immediately.
*/
void
psignal(struct proc *p, int sig)
{
struct thread *td;
int prop;
PROC_LOCK_ASSERT(p, MA_OWNED);
prop = sigprop(sig);
/*
* Find a thread to deliver the signal to.
*/
td = sigtd(p, sig, prop);
tdsignal(td, sig);
}
void
tdsignal(struct thread *td, int sig)
{
struct proc *p;
register sig_t action;
sigset_t *siglist;
struct thread *td0;
register int prop;
KASSERT(_SIG_VALID(sig),
("tdsignal(): invalid signal %d\n", sig));
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
prop = sigprop(sig);
/*
* If this thread is blocking this signal then we'll leave it in the
* proc so that we can find it in the first thread that unblocks it.
*/
if (SIGISMEMBER(td->td_sigmask, sig))
siglist = &p->p_siglist;
else
siglist = &td->td_siglist;
/*
* If proc is traced, always give parent a chance;
* if signal event is tracked by procfs, give *that*
* a chance, as well.
*/
if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
action = SIG_DFL;
} else {
/*
* If the signal is being ignored,
* then we forget about it immediately.
* (Note: we don't set SIGCONT in p_sigignore,
* and if it is set to SIG_IGN,
* action will be SIG_DFL here.)
*/
if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
return;
if (SIGISMEMBER(td->td_sigmask, sig))
action = SIG_HOLD;
else if (SIGISMEMBER(p->p_sigcatch, sig))
action = SIG_CATCH;
else
action = SIG_DFL;
}
if (prop & SA_CONT) {
SIG_STOPSIGMASK(p->p_siglist);
/*
* XXX Should investigate leaving STOP and CONT sigs only in
* the proc's siglist.
*/
FOREACH_THREAD_IN_PROC(p, td0)
SIG_STOPSIGMASK(td0->td_siglist);
}
if (prop & SA_STOP) {
/*
* If sending a tty stop signal to a member of an orphaned
* process group, discard the signal here if the action
* is default; don't stop the process below if sleeping,
* and don't clear any pending SIGCONT.
*/
if ((prop & SA_TTYSTOP) &&
(p->p_pgrp->pg_jobc == 0) &&
(action == SIG_DFL))
return;
SIG_CONTSIGMASK(p->p_siglist);
FOREACH_THREAD_IN_PROC(p, td0)
SIG_CONTSIGMASK(td0->td_siglist);
p->p_flag &= ~P_CONTINUED;
}
SIGADDSET(*siglist, sig);
signotify(td); /* uses schedlock */
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD &&
!((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
return;
/*
* Some signals have a process-wide effect and a per-thread
* component. Most processing occurs when the process next
* tries to cross the user boundary, however there are some
* times when processing needs to be done immediatly, such as
* waking up threads so that they can cross the user boundary.
* We try do the per-process part here.
*/
if (P_SHOULDSTOP(p)) {
/*
* The process is in stopped mode. All the threads should be
* either winding down or already on the suspended queue.
*/
if (p->p_flag & P_TRACED) {
/*
* The traced process is already stopped,
* so no further action is necessary.
* No signal can restart us.
*/
goto out;
}
if (sig == SIGKILL) {
/*
* SIGKILL sets process running.
* It will die elsewhere.
* All threads must be restarted.
*/
p->p_flag &= ~P_STOPPED;
goto runfast;
}
if (prop & SA_CONT) {
/*
* If SIGCONT is default (or ignored), we continue the
* process but don't leave the signal in siglist as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* siglist. If the process catches SIGCONT, let it
* handle the signal itself. If it isn't waiting on
* an event, it goes back to run state.
* Otherwise, process goes back to sleep state.
*/
p->p_flag &= ~P_STOPPED_SIG;
p->p_flag |= P_CONTINUED;
if (action == SIG_DFL) {
SIGDELSET(*siglist, sig);
} else if (action == SIG_CATCH) {
/*
* The process wants to catch it so it needs
* to run at least one thread, but which one?
* It would seem that the answer would be to
* run an upcall in the next KSE to run, and
* deliver the signal that way. In a NON KSE
* process, we need to make sure that the
* single thread is runnable asap.
* XXXKSE for now however, make them all run.
*/
goto runfast;
}
/*
* The signal is not ignored or caught.
*/
mtx_lock_spin(&sched_lock);
thread_unsuspend(p);
mtx_unlock_spin(&sched_lock);
goto out;
}
if (prop & SA_STOP) {
/*
* Already stopped, don't need to stop again
* (If we did the shell could get confused).
* Just make sure the signal STOP bit set.
*/
p->p_flag |= P_STOPPED_SIG;
SIGDELSET(*siglist, sig);
goto out;
}
/*
* All other kinds of signals:
* If a thread is sleeping interruptibly, simulate a
* wakeup so that when it is continued it will be made
* runnable and can look at the signal. However, don't make
* the PROCESS runnable, leave it stopped.
* It may run a bit until it hits a thread_suspend_check().
*/
mtx_lock_spin(&sched_lock);
if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR)) {
if (td->td_flags & TDF_CVWAITQ)
cv_abort(td);
else
abortsleep(td);
}
mtx_unlock_spin(&sched_lock);
goto out;
/*
* XXXKSE What about threads that are waiting on mutexes?
* Shouldn't they abort too?
* No, hopefully mutexes are short lived.. They'll
* eventually hit thread_suspend_check().
*/
} else if (p->p_state == PRS_NORMAL) {
if ((p->p_flag & P_TRACED) || (action != SIG_DFL) ||
!(prop & SA_STOP)) {
mtx_lock_spin(&sched_lock);
tdsigwakeup(td, sig, action);
mtx_unlock_spin(&sched_lock);
goto out;
}
if (prop & SA_STOP) {
if (p->p_flag & P_PPWAIT)
goto out;
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td0) {
if (TD_IS_SLEEPING(td0) &&
(td->td_flags & TDF_SINTR))
thread_suspend_one(td0);
}
thread_stopped(p);
if (p->p_numthreads == p->p_suspcount) {
SIGDELSET(p->p_siglist, p->p_xstat);
FOREACH_THREAD_IN_PROC(p, td0)
SIGDELSET(td0->td_siglist, p->p_xstat);
}
mtx_unlock_spin(&sched_lock);
goto out;
}
else
goto runfast;
/* NOTREACHED */
} else {
/* Not in "NORMAL" state. discard the signal. */
SIGDELSET(*siglist, sig);
goto out;
}
/*
* The process is not stopped so we need to apply the signal to all the
* running threads.
*/
runfast:
mtx_lock_spin(&sched_lock);
tdsigwakeup(td, sig, action);
thread_unsuspend(p);
mtx_unlock_spin(&sched_lock);
out:
/* If we jump here, sched_lock should not be owned. */
mtx_assert(&sched_lock, MA_NOTOWNED);
}
/*
* The force of a signal has been directed against a single
* thread. We need to see what we can do about knocking it
* out of any sleep it may be in etc.
*/
static void
tdsigwakeup(struct thread *td, int sig, sig_t action)
{
struct proc *p = td->td_proc;
register int prop;
mtx_assert(&sched_lock, MA_OWNED);
prop = sigprop(sig);
/*
* Bring the priority of a thread up if we want it to get
* killed in this lifetime.
*/
if ((action == SIG_DFL) && (prop & SA_KILL)) {
if (td->td_priority > PUSER) {
td->td_priority = PUSER;
}
}
if (TD_IS_SLEEPING(td)) {
/*
* If thread is sleeping uninterruptibly
* we can't interrupt the sleep... the signal will
* be noticed when the process returns through
* trap() or syscall().
*/
if ((td->td_flags & TDF_SINTR) == 0) {
return;
}
/*
* Process is sleeping and traced. Make it runnable
* so it can discover the signal in issignal() and stop
* for its parent.
*/
if (p->p_flag & P_TRACED) {
p->p_flag &= ~P_STOPPED_TRACE;
} else {
/*
* If SIGCONT is default (or ignored) and process is
* asleep, we are finished; the process should not
* be awakened.
*/
if ((prop & SA_CONT) && action == SIG_DFL) {
SIGDELSET(p->p_siglist, sig);
/*
* It may be on either list in this state.
* Remove from both for now.
*/
SIGDELSET(td->td_siglist, sig);
return;
}
/*
* Raise priority to at least PUSER.
*/
if (td->td_priority > PUSER) {
td->td_priority = PUSER;
}
}
if (td->td_flags & TDF_CVWAITQ)
cv_abort(td);
else
abortsleep(td);
}
#ifdef SMP
else {
/*
* Other states do nothing with the signal immediatly,
* other than kicking ourselves if we are running.
* It will either never be noticed, or noticed very soon.
*/
if (TD_IS_RUNNING(td) && td != curthread) {
forward_signal(td);
}
}
#endif
}
/*
* If the current process has received a signal (should be caught or cause
* termination, should interrupt current syscall), return the signal number.
* Stop signals with default action are processed immediately, then cleared;
* they aren't returned. This is checked after each entry to the system for
* a syscall or trap (though this can usually be done without calling issignal
* by checking the pending signal masks in cursig.) The normal call
* sequence is
*
* while (sig = cursig(curthread))
* postsig(sig);
*/
int
issignal(td)
struct thread *td;
{
struct proc *p;
sigset_t sigpending;
register int sig, prop;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &p->p_mtx.mtx_object,
"Checking for signals");
for (;;) {
int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
sigpending = td->td_siglist;
SIGSETNAND(sigpending, td->td_sigmask);
if (p->p_flag & P_PPWAIT)
SIG_STOPSIGMASK(sigpending);
if (SIGISEMPTY(sigpending)) /* no signal to send */
return (0);
sig = sig_ffs(&sigpending);
prop = sigprop(sig);
_STOPEVENT(p, S_SIG, sig);
/*
* We should see pending but ignored signals
* only if P_TRACED was on when they were posted.
*/
if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
SIGDELSET(td->td_siglist, sig);
continue;
}
if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
/*
* If traced, always stop.
*/
p->p_xstat = sig;
PROC_LOCK(p->p_pptr);
psignal(p->p_pptr, SIGCHLD);
PROC_UNLOCK(p->p_pptr);
mtx_lock_spin(&sched_lock);
stop(p); /* uses schedlock too eventually */
thread_suspend_one(td);
PROC_UNLOCK(p);
DROP_GIANT();
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
PROC_LOCK(p);
/*
* If the traced bit got turned off, go back up
* to the top to rescan signals. This ensures
* that p_sig* and ps_sigact are consistent.
*/
if ((p->p_flag & P_TRACED) == 0)
continue;
/*
* If parent wants us to take the signal,
* then it will leave it in p->p_xstat;
* otherwise we just look for signals again.
*/
SIGDELSET(td->td_siglist, sig); /* clear old signal */
sig = p->p_xstat;
if (sig == 0)
continue;
/*
* Put the new signal into td_siglist. If the
* signal is being masked, look for other signals.
*/
SIGADDSET(td->td_siglist, sig);
if (SIGISMEMBER(td->td_sigmask, sig))
continue;
signotify(td);
}
/*
* Decide whether the signal should be returned.
* Return the signal's number, or fall through
* to clear it from the pending mask.
*/
switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
case (intptr_t)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (p->p_pid <= 1) {
#ifdef DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %lu) got signal %d\n",
(u_long)p->p_pid, sig);
#endif
break; /* == ignore */
}
/*
* If there is a pending stop signal to process
* with default action, stop here,
* then clear the signal. However,
* if process is member of an orphaned
* process group, ignore tty stop signals.
*/
if (prop & SA_STOP) {
if (p->p_flag & P_TRACED ||
(p->p_pgrp->pg_jobc == 0 &&
prop & SA_TTYSTOP))
break; /* == ignore */
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
mtx_lock_spin(&sched_lock);
thread_stopped(p);
thread_suspend_one(td);
PROC_UNLOCK(p);
DROP_GIANT();
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
PROC_LOCK(p);
break;
} else if (prop & SA_IGNORE) {
/*
* Except for SIGCONT, shouldn't get here.
* Default action is to ignore; drop it.
*/
break; /* == ignore */
} else
return (sig);
/*NOTREACHED*/
case (intptr_t)SIG_IGN:
/*
* Masking above should prevent us ever trying
* to take action on an ignored signal other
* than SIGCONT, unless process is traced.
*/
if ((prop & SA_CONT) == 0 &&
(p->p_flag & P_TRACED) == 0)
printf("issignal\n");
break; /* == ignore */
default:
/*
* This signal has an action, let
* postsig() process it.
*/
return (sig);
}
SIGDELSET(td->td_siglist, sig); /* take the signal! */
}
/* NOTREACHED */
}
/*
* Put the argument process into the stopped state and notify the parent
* via wakeup. Signals are handled elsewhere. The process must not be
* on the run queue. Must be called with the proc p locked and the scheduler
* lock held.
*/
static void
stop(struct proc *p)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_flag |= P_STOPPED_SIG;
p->p_flag &= ~P_WAITED;
wakeup(p->p_pptr);
}
void
thread_stopped(struct proc *p)
{
struct proc *p1 = curthread->td_proc;
int n;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
n = p->p_suspcount;
if (p == p1)
n++;
if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
mtx_unlock_spin(&sched_lock);
stop(p);
PROC_LOCK(p->p_pptr);
if ((p->p_pptr->p_procsig->ps_flag &
PS_NOCLDSTOP) == 0) {
psignal(p->p_pptr, SIGCHLD);
}
PROC_UNLOCK(p->p_pptr);
mtx_lock_spin(&sched_lock);
}
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(sig)
register int sig;
{
struct thread *td = curthread;
register struct proc *p = td->td_proc;
struct sigacts *ps;
sig_t action;
sigset_t returnmask;
int code;
KASSERT(sig != 0, ("postsig"));
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
SIGDELSET(td->td_siglist, sig);
action = ps->ps_sigact[_SIG_IDX(sig)];
#ifdef KTRACE
if (KTRPOINT(td, KTR_PSIG))
ktrpsig(sig, action, td->td_flags & TDF_OLDMASK ?
&td->td_oldsigmask : &td->td_sigmask, 0);
#endif
_STOPEVENT(p, S_SIG, sig);
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
sigexit(td, sig);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
("postsig action"));
/*
* Set the new mask value and also defer further
* occurrences of this signal.
*
* Special case: user has done a sigsuspend. Here the
* current mask is not of interest, but rather the
* mask from before the sigsuspend is what we want
* restored after the signal processing is completed.
*/
mtx_lock_spin(&sched_lock);
if (td->td_flags & TDF_OLDMASK) {
returnmask = td->td_oldsigmask;
td->td_flags &= ~TDF_OLDMASK;
} else
returnmask = td->td_sigmask;
mtx_unlock_spin(&sched_lock);
SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(td->td_sigmask, sig);
if (SIGISMEMBER(ps->ps_sigreset, sig)) {
/*
* See kern_sigaction() for origin of this code.
*/
SIGDELSET(p->p_sigcatch, sig);
if (sig != SIGCONT &&
sigprop(sig) & SA_IGNORE)
SIGADDSET(p->p_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
p->p_stats->p_ru.ru_nsignals++;
if (p->p_sig != sig) {
code = 0;
} else {
code = p->p_code;
p->p_code = 0;
p->p_sig = 0;
}
if (p->p_flag & P_THREADED)
thread_signal_add(curthread, sig);
else
(*p->p_sysent->sv_sendsig)(action, sig,
&returnmask, code);
}
}
/*
* Kill the current process for stated reason.
*/
void
killproc(p, why)
struct proc *p;
char *why;
{
PROC_LOCK_ASSERT(p, MA_OWNED);
CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)",
p, p->p_pid, p->p_comm);
log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
p->p_ucred ? p->p_ucred->cr_uid : -1, why);
psignal(p, SIGKILL);
}
/*
* Force the current process to exit with the specified signal, dumping core
* if appropriate. We bypass the normal tests for masked and caught signals,
* allowing unrecoverable failures to terminate the process without changing
* signal state. Mark the accounting record with the signal termination.
* If dumping core, save the signal number for the debugger. Calls exit and
* does not return.
*/
void
sigexit(td, sig)
struct thread *td;
int sig;
{
struct proc *p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_acflag |= AXSIG;
if (sigprop(sig) & SA_CORE) {
p->p_sig = sig;
/*
* Log signals which would cause core dumps
* (Log as LOG_INFO to appease those who don't want
* these messages.)
* XXX : Todo, as well as euid, write out ruid too
*/
PROC_UNLOCK(p);
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
if (coredump(td) == 0)
sig |= WCOREFLAG;
if (kern_logsigexit)
log(LOG_INFO,
"pid %d (%s), uid %d: exited on signal %d%s\n",
p->p_pid, p->p_comm,
td->td_ucred ? td->td_ucred->cr_uid : -1,
sig &~ WCOREFLAG,
sig & WCOREFLAG ? " (core dumped)" : "");
} else {
PROC_UNLOCK(p);
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
}
exit1(td, W_EXITCODE(0, sig));
/* NOTREACHED */
}
static char corefilename[MAXPATHLEN+1] = {"%N.core"};
SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
sizeof(corefilename), "process corefile name format string");
/*
* expand_name(name, uid, pid)
* Expand the name described in corefilename, using name, uid, and pid.
* corefilename is a printf-like string, with three format specifiers:
* %N name of process ("name")
* %P process id (pid)
* %U user id (uid)
* For example, "%N.core" is the default; they can be disabled completely
* by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
* This is controlled by the sysctl variable kern.corefile (see above).
*/
static char *
expand_name(name, uid, pid)
const char *name;
uid_t uid;
pid_t pid;
{
const char *format, *appendstr;
char *temp;
char buf[11]; /* Buffer for pid/uid -- max 4B */
size_t i, l, n;
format = corefilename;
temp = malloc(MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
if (temp == NULL)
return (NULL);
for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
switch (format[i]) {
case '%': /* Format character */
i++;
switch (format[i]) {
case '%':
appendstr = "%";
break;
case 'N': /* process name */
appendstr = name;
break;
case 'P': /* process id */
sprintf(buf, "%u", pid);
appendstr = buf;
break;
case 'U': /* user id */
sprintf(buf, "%u", uid);
appendstr = buf;
break;
default:
appendstr = "";
log(LOG_ERR,
"Unknown format character %c in `%s'\n",
format[i], format);
}
l = strlen(appendstr);
if ((n + l) >= MAXPATHLEN)
goto toolong;
memcpy(temp + n, appendstr, l);
n += l;
break;
default:
temp[n++] = format[i];
}
}
if (format[i] != '\0')
goto toolong;
return (temp);
toolong:
log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too long\n",
(long)pid, name, (u_long)uid);
free(temp, M_TEMP);
return (NULL);
}
/*
* Dump a process' core. The main routine does some
* policy checking, and creates the name of the coredump;
* then it passes on a vnode and a size limit to the process-specific
* coredump routine if there is one; if there _is not_ one, it returns
* ENOSYS; otherwise it returns the error from the process-specific routine.
*/
static int
coredump(struct thread *td)
{
struct proc *p = td->td_proc;
register struct vnode *vp;
register struct ucred *cred = td->td_ucred;
struct flock lf;
struct nameidata nd;
struct vattr vattr;
int error, error1, flags;
struct mount *mp;
char *name; /* name of corefile */
off_t limit;
PROC_LOCK(p);
_STOPEVENT(p, S_CORE, 0);
if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) {
PROC_UNLOCK(p);
return (EFAULT);
}
/*
* Note that the bulk of limit checking is done after
* the corefile is created. The exception is if the limit
* for corefiles is 0, in which case we don't bother
* creating the corefile at all. This layout means that
* a corefile is truncated instead of not being created,
* if it is larger than the limit.
*/
limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
if (limit == 0) {
PROC_UNLOCK(p);
return 0;
}
PROC_UNLOCK(p);
restart:
name = expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid);
if (name == NULL)
return (EINVAL);
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); /* XXXKSE */
flags = O_CREAT | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, S_IRUSR | S_IWUSR);
free(name, M_TEMP);
if (error)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred, td) || vattr.va_nlink != 1) {
VOP_UNLOCK(vp, 0, td);
error = EFAULT;
goto out2;
}
VOP_UNLOCK(vp, 0, td);
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_WRLCK;
error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK);
if (error)
goto out2;
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
lf.l_type = F_UNLCK;
VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
return (error);
if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
return (error);
goto restart;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
VOP_LEASE(vp, td, cred, LEASE_WRITE);
VOP_SETATTR(vp, &vattr, cred, td);
VOP_UNLOCK(vp, 0, td);
PROC_LOCK(p);
p->p_acflag |= ACORE;
PROC_UNLOCK(p);
error = p->p_sysent->sv_coredump ?
p->p_sysent->sv_coredump(td, vp, limit) :
ENOSYS;
lf.l_type = F_UNLCK;
VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
vn_finished_write(mp);
out2:
error1 = vn_close(vp, FWRITE, cred, td);
if (error == 0)
error = error1;
return (error);
}
/*
* Nonexistent system call-- signal process (may want to handle it).
* Flag error in case process won't see signal immediately (blocked or ignored).
*/
#ifndef _SYS_SYSPROTO_H_
struct nosys_args {
int dummy;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
nosys(td, args)
struct thread *td;
struct nosys_args *args;
{
struct proc *p = td->td_proc;
mtx_lock(&Giant);
PROC_LOCK(p);
psignal(p, SIGSYS);
PROC_UNLOCK(p);
mtx_unlock(&Giant);
return (ENOSYS);
}
/*
* Send a SIGIO or SIGURG signal to a process or process group using
* stored credentials rather than those of the current process.
*/
void
pgsigio(sigiop, sig, checkctty)
struct sigio **sigiop;
int sig, checkctty;
{
struct sigio *sigio;
SIGIO_LOCK();
sigio = *sigiop;
if (sigio == NULL) {
SIGIO_UNLOCK();
return;
}
if (sigio->sio_pgid > 0) {
PROC_LOCK(sigio->sio_proc);
if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
psignal(sigio->sio_proc, sig);
PROC_UNLOCK(sigio->sio_proc);
} else if (sigio->sio_pgid < 0) {
struct proc *p;
PGRP_LOCK(sigio->sio_pgrp);
LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
(checkctty == 0 || (p->p_flag & P_CONTROLT)))
psignal(p, sig);
PROC_UNLOCK(p);
}
PGRP_UNLOCK(sigio->sio_pgrp);
}
SIGIO_UNLOCK();
}
static int
filt_sigattach(struct knote *kn)
{
struct proc *p = curproc;
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
PROC_LOCK(p);
SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
PROC_UNLOCK(p);
return (0);
}
static void
filt_sigdetach(struct knote *kn)
{
struct proc *p = kn->kn_ptr.p_proc;
PROC_LOCK(p);
SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
PROC_UNLOCK(p);
}
/*
* signal knotes are shared with proc knotes, so we apply a mask to
* the hint in order to differentiate them from process hints. This
* could be avoided by using a signal-specific knote list, but probably
* isn't worth the trouble.
*/
static int
filt_signal(struct knote *kn, long hint)
{
if (hint & NOTE_SIGNAL) {
hint &= ~NOTE_SIGNAL;
if (kn->kn_id == hint)
kn->kn_data++;
}
return (kn->kn_data != 0);
}
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