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4444375710
freebsd-dev/sys/kern/kern_sig.c
Tim J. Robbins 4444375710 Acquire Giant around calls to kern_sigaction() in sigaction(), 
freebsd4_sigaction() and osigaction() instead of around the whole
body of those functions. They now no longer hold Giant around calls
to copyin() and copyout(), and it is slightly more obvious what
Giant is protecting.
2003-02-15 09:56:09 +00:00

2282 lines
54 KiB
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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 int do_sigprocmask(struct proc *p, int how, sigset_t *set,
sigset_t *oset, int old);
static char *expand_name(const char *, uid_t, pid_t);
static int killpg1(struct thread *td, int sig, int pgid, int all);
static int sig_ffs(sigset_t *set);
static int sigprop(int sig);
static void stop(struct proc *);
static void tdsignal(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);
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 */
static int sigproptbl[NSIG] = {
SA_KILL, /* SIGHUP */
SA_KILL, /* SIGINT */
SA_KILL|SA_CORE, /* SIGQUIT */
SA_KILL|SA_CORE, /* SIGILL */
SA_KILL|SA_CORE, /* SIGTRAP */
SA_KILL|SA_CORE, /* SIGABRT */
SA_KILL|SA_CORE, /* SIGEMT */
SA_KILL|SA_CORE, /* SIGFPE */
SA_KILL, /* SIGKILL */
SA_KILL|SA_CORE, /* SIGBUS */
SA_KILL|SA_CORE, /* SIGSEGV */
SA_KILL|SA_CORE, /* SIGSYS */
SA_KILL, /* SIGPIPE */
SA_KILL, /* SIGALRM */
SA_KILL, /* SIGTERM */
SA_IGNORE, /* SIGURG */
SA_STOP, /* SIGSTOP */
SA_STOP|SA_TTYSTOP, /* SIGTSTP */
SA_IGNORE|SA_CONT, /* SIGCONT */
SA_IGNORE, /* SIGCHLD */
SA_STOP|SA_TTYSTOP, /* SIGTTIN */
SA_STOP|SA_TTYSTOP, /* SIGTTOU */
SA_IGNORE, /* SIGIO */
SA_KILL, /* SIGXCPU */
SA_KILL, /* SIGXFSZ */
SA_KILL, /* SIGVTALRM */
SA_KILL, /* SIGPROF */
SA_IGNORE, /* SIGWINCH */
SA_IGNORE, /* SIGINFO */
SA_KILL, /* SIGUSR1 */
SA_KILL, /* 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)
{
struct proc *p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_NOTOWNED);
return (SIGPENDING(p) ? 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 p_siglist or
* unmasked in p_sigmask.
*/
void
signotify(struct proc *p)
{
struct kse *ke;
struct ksegrp *kg;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_lock_spin(&sched_lock);
if (SIGPENDING(p)) {
p->p_sflag |= PS_NEEDSIGCHK;
/* XXXKSE for now punish all KSEs */
FOREACH_KSEGRP_IN_PROC(p, kg) {
FOREACH_KSE_IN_GROUP(kg, ke) {
ke->ke_flags |= KEF_ASTPENDING;
}
}
}
mtx_unlock_spin(&sched_lock);
}
static __inline int
sigprop(int sig)
{
if (sig > 0 && sig < NSIG)
return (sigproptbl[_SIG_IDX(sig)]);
return (0);
}
static __inline 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 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);
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 p_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);
}
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
/*
* 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(p, how, set, oset, old)
struct proc *p;
int how;
sigset_t *set, *oset;
int old;
{
int error;
PROC_LOCK(p);
if (oset != NULL)
*oset = p->p_sigmask;
error = 0;
if (set != NULL) {
switch (how) {
case SIG_BLOCK:
SIG_CANTMASK(*set);
SIGSETOR(p->p_sigmask, *set);
break;
case SIG_UNBLOCK:
SIGSETNAND(p->p_sigmask, *set);
signotify(p);
break;
case SIG_SETMASK:
SIG_CANTMASK(*set);
if (old)
SIGSETLO(p->p_sigmask, *set);
else
p->p_sigmask = *set;
signotify(p);
break;
default:
error = EINVAL;
break;
}
}
PROC_UNLOCK(p);
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;
{
struct proc *p = td->td_proc;
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(p, 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;
{
struct proc *p = td->td_proc;
sigset_t set, oset;
int error;
OSIG2SIG(uap->mask, set);
error = do_sigprocmask(p, 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
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;
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;
PROC_LOCK(p);
SIG2OSIG(p->p_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, 1);
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(p->p_sigmask, td->td_retval[0]);
SIGSETOR(p->p_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(p->p_sigmask, td->td_retval[0]);
SIGSETLO(p->p_sigmask, set);
signotify(p);
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;
p->p_oldsigmask = p->p_sigmask;
p->p_flag |= P_OLDMASK;
SIG_CANTMASK(mask);
p->p_sigmask = mask;
signotify(p);
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;
p->p_oldsigmask = p->p_sigmask;
p->p_flag |= P_OLDMASK;
OSIG2SIG(uap->mask, mask);
SIG_CANTMASK(mask);
SIGSETLO(p->p_sigmask, mask);
signotify(p);
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 process.
* If it will be caught immediately, deliver it with correct code.
* Otherwise, post it normally.
*
* MPSAFE
*/
void
trapsignal(p, sig, code)
struct proc *p;
register int sig;
u_long code;
{
register struct sigacts *ps = p->p_sigacts;
PROC_LOCK(p);
if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
!SIGISMEMBER(p->p_sigmask, sig)) {
p->p_stats->p_ru.ru_nsignals++;
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_PSIG))
ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
&p->p_sigmask, code);
#endif
(*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
&p->p_sigmask, code);
SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(p->p_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 */
psignal(p, sig);
}
PROC_UNLOCK(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(p, sig)
register struct proc *p;
register int sig;
{
register sig_t action;
struct thread *td;
register int prop;
KASSERT(_SIG_VALID(sig),
("psignal(): invalid signal %d\n", sig));
PROC_LOCK_ASSERT(p, MA_OWNED);
KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
prop = sigprop(sig);
/*
* 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(p->p_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);
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);
p->p_flag &= ~P_CONTINUED;
}
SIGADDSET(p->p_siglist, sig);
signotify(p); /* uses schedlock */
/*
* 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 p_siglist as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* p_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(p->p_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(p->p_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);
FOREACH_THREAD_IN_PROC(p, td) {
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 (prop & SA_CONT) {
/*
* Already active, don't need to start again.
*/
SIGDELSET(p->p_siglist, sig);
goto out;
}
if ((p->p_flag & P_TRACED) || (action != SIG_DFL) ||
!(prop & SA_STOP)) {
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td)
tdsignal(td, sig, action);
mtx_unlock_spin(&sched_lock);
goto out;
}
if (prop & SA_STOP) {
if (p->p_flag & P_PPWAIT)
goto out;
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td) {
if (TD_IS_SLEEPING(td) &&
(td->td_flags & TDF_SINTR))
thread_suspend_one(td);
else if (TD_IS_IDLE(td)) {
thread_suspend_one(td);
}
}
if (p->p_suspcount == p->p_numthreads) {
mtx_unlock_spin(&sched_lock);
stop(p);
p->p_xstat = sig;
SIGDELSET(p->p_siglist, sig);
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);
} else {
mtx_unlock_spin(&sched_lock);
}
goto out;
}
else
goto runfast;
/* NOTREACHED */
} else {
/* Not in "NORMAL" state. discard the signal. */
SIGDELSET(p->p_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);
FOREACH_THREAD_IN_PROC(p, td)
tdsignal(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
tdsignal(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;
}
}
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD) {
return;
}
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);
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);
} else if (TD_IS_IDLE(td)) {
TD_CLR_IDLE(td);
setrunnable(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 mask;
register int sig, prop;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
WITNESS_SLEEP(1, &p->p_mtx.mtx_object);
for (;;) {
int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
mask = p->p_siglist;
SIGSETNAND(mask, p->p_sigmask);
if (p->p_flag & P_PPWAIT)
SIG_STOPSIGMASK(mask);
if (SIGISEMPTY(mask)) /* no signal to send */
return (0);
sig = sig_ffs(&mask);
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(p->p_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(p->p_siglist, sig); /* clear old signal */
sig = p->p_xstat;
if (sig == 0)
continue;
/*
* Put the new signal into p_siglist. If the
* signal is being masked, look for other signals.
*/
SIGADDSET(p->p_siglist, sig);
if (SIGISMEMBER(p->p_sigmask, sig))
continue;
signotify(p);
}
/*
* 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_xstat = sig;
mtx_lock_spin(&sched_lock);
if (p->p_suspcount+1 == p->p_numthreads) {
mtx_unlock_spin(&sched_lock);
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);
}
stop(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(p->p_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(p)
register struct proc *p;
{
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_flag |= P_STOPPED_SIG;
p->p_flag &= ~P_WAITED;
wakeup(p->p_pptr);
}
/*
* 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(p->p_siglist, sig);
action = ps->ps_sigact[_SIG_IDX(sig)];
#ifdef KTRACE
if (KTRPOINT(td, KTR_PSIG))
ktrpsig(sig, action, p->p_flag & P_OLDMASK ?
&p->p_oldsigmask : &p->p_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(p->p_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.
*/
if (p->p_flag & P_OLDMASK) {
returnmask = p->p_oldsigmask;
p->p_flag &= ~P_OLDMASK;
} else
returnmask = p->p_sigmask;
SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(p->p_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_KSES)
if (signal_upcall(p, sig))
return;
(*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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