Source to bsd/kern/kern_sig.c
/*
* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* The contents of this file constitute Original Code as defined in and
* are subject to the Apple Public Source License Version 1.1 (the
* "License"). You may not use this file except in compliance with the
* License. Please obtain a copy of the License at
* http://www.apple.com/publicsource and read it before using this file.
*
* This Original Code and all software distributed under the License are
* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
* License for the specific language governing rights and limitations
* under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/* Copyright (c) 1995-1998 Apple Computer, Inc. All Rights Reserved */
/*
* 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
*/
#define SIGPROP /* include signal properties table */
#include <sys/param.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/buf.h>
#include <sys/acct.h>
#include <sys/file.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/ktrace.h>
#include <sys/syslog.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <kern/cpu_number.h>
#include <sys/vm.h>
#include <sys/user.h> /* for coredump */
#include <kern/ast.h> /* for APC support */
#include <kern/thread.h>
void stop __P((struct proc *p));
int cansignal __P((struct proc *, struct pcred *, struct proc *, int));
int killpg1 __P((struct proc *, int, int, int));
void sigexit __P((struct proc *, int));
void setsigvec __P((struct proc *, int, struct sigaction *));
void exit1 __P((struct proc *, int));
/*
* Can process p, with pcred pc, send the signal signum to process q?
*/
int
cansignal(p, pc, q, signum)
struct proc *p;
struct pcred *pc;
struct proc *q;
int signum;
{
if (pc->pc_ucred->cr_uid == 0)
return (1); /* root can always signal */
if (signum == SIGCONT && q->p_session == p->p_session)
return (1); /* SIGCONT in session */
/*
* Using kill(), only certain signals can be sent to setugid
* child processes
*/
if (q->p_flag & P_SUGID) {
switch (signum) {
case 0:
case SIGKILL:
case SIGINT:
case SIGTERM:
case SIGSTOP:
case SIGTTIN:
case SIGTTOU:
case SIGTSTP:
case SIGHUP:
case SIGUSR1:
case SIGUSR2:
if (pc->p_ruid == q->p_cred->p_ruid ||
pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
pc->p_ruid == q->p_ucred->cr_uid ||
pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
return (1);
}
return (0);
}
/* XXX
* because the P_SUGID test exists, this has extra tests which
* could be removed.
*/
if (pc->p_ruid == q->p_cred->p_ruid ||
pc->p_ruid == q->p_cred->p_svuid ||
pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
pc->pc_ucred->cr_uid == q->p_cred->p_svuid ||
pc->p_ruid == q->p_ucred->cr_uid ||
pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
return (1);
return (0);
}
struct sigaction_args {
int signum;
struct sigaction *nsa;
struct sigaction *osa;
};
/* ARGSUSED */
int
sigaction(p, uap, retval)
struct proc *p;
register struct sigaction_args *uap;
register_t *retval;
{
struct sigaction vec;
register struct sigaction *sa;
register struct sigacts *ps = p->p_sigacts;
register int signum;
int bit, error;
signum = uap->signum;
if (signum <= 0 || signum >= NSIG ||
signum == SIGKILL || signum == SIGSTOP)
return (EINVAL);
sa = &vec;
if (uap->osa) {
sa->sa_handler = ps->ps_sigact[signum];
sa->sa_mask = ps->ps_catchmask[signum];
bit = sigmask(signum);
sa->sa_flags = 0;
if ((ps->ps_sigonstack & bit) != 0)
sa->sa_flags |= SA_ONSTACK;
if ((ps->ps_sigintr & bit) == 0)
sa->sa_flags |= SA_RESTART;
if (p->p_flag & P_NOCLDSTOP)
sa->sa_flags |= SA_NOCLDSTOP;
if (error = copyout((caddr_t)sa, (caddr_t)uap->osa,
sizeof (vec)))
return (error);
}
if (uap->nsa) {
if (error = copyin((caddr_t)uap->nsa, (caddr_t)sa,
sizeof (vec)))
return (error);
setsigvec(p, signum, sa);
}
return (0);
}
bsd_resetbit(thread_act_t th_act, int bit)
{
struct uthread *ut;
ut = get_bsdthread_info(th_act);
if (ut) {
ut->uu_sig &= ~bit;
}
}
void
setsigvec(p, signum, sa)
register struct proc *p;
int signum;
register struct sigaction *sa;
{
register struct sigacts *ps = p->p_sigacts;
register int bit;
bit = sigmask(signum);
/*
* Change setting atomically.
*/
(void) splhigh();
simple_lock(&p->siglock);
ps->ps_sigact[signum] = sa->sa_handler;
ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
if ((sa->sa_flags & SA_RESTART) == 0)
ps->ps_sigintr |= bit;
else
ps->ps_sigintr &= ~bit;
if (sa->sa_flags & SA_ONSTACK)
ps->ps_sigonstack |= bit;
else
ps->ps_sigonstack &= ~bit;
if (sa->sa_flags & SA_USERTRAMP)
ps->ps_usertramp |= bit;
else
ps->ps_usertramp &= ~bit;
if (signum == SIGCHLD) {
if (sa->sa_flags & SA_NOCLDSTOP)
p->p_flag |= P_NOCLDSTOP;
else
p->p_flag &= ~P_NOCLDSTOP;
}
/*
* 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 (sa->sa_handler == SIG_IGN ||
(sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
p->p_siglist &= ~bit; /* never to be seen again */
/*
* If this is a thread signal, clean out the
* threads as well.
*/
if (bit & threadmask) {
register task_t task = p->task;
task_act_iterate_wth_args(task, bsd_resetbit, bit);
}
if (signum != SIGCONT)
p->p_sigignore |= bit; /* easier in psignal */
p->p_sigcatch &= ~bit;
} else {
p->p_sigignore &= ~bit;
if (sa->sa_handler == SIG_DFL)
p->p_sigcatch &= ~bit;
else
p->p_sigcatch |= bit;
}
simple_unlock(&p->siglock);
(void) spl0();
}
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(p)
struct proc *p;
{
register int i;
for (i = 0; i < NSIG; i++)
if (sigprop[i] & SA_IGNORE && i != SIGCONT)
p->p_sigignore |= sigmask(i);
}
/*
* Reset signals for an exec of the specified process.
*/
void
execsigs(p)
register struct proc *p;
{
register struct sigacts *ps = p->p_sigacts;
register int nc, mask;
/*
* Reset caught signals. Held signals remain held
* through p_sigmask (unless they were caught,
* and are now ignored by default).
*/
while (p->p_sigcatch) {
nc = ffs((long)p->p_sigcatch);
mask = sigmask(nc);
p->p_sigcatch &= ~mask;
if (sigprop[nc] & SA_IGNORE) {
if (nc != SIGCONT)
p->p_sigignore |= mask;
p->p_siglist &= ~mask;
}
ps->ps_sigact[nc] = SIG_DFL;
}
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
ps->ps_sigstk.ss_flags = SA_DISABLE;
ps->ps_sigstk.ss_size = 0;
ps->ps_sigstk.ss_sp = 0;
ps->ps_flags = 0;
}
/*
* Manipulate signal mask.
* Note that we receive new mask, not pointer,
* and return old mask as return value;
* the library stub does the rest.
*/
struct sigprocmask_args {
int how;
sigset_t mask;
};
int
sigprocmask(p, uap, retval)
register struct proc *p;
struct sigprocmask_args *uap;
register_t *retval;
{
int error = 0;
*retval = p->p_sigmask;
(void) splhigh();
switch (uap->how) {
case SIG_BLOCK:
p->p_sigmask |= uap->mask &~ sigcantmask;
break;
case SIG_UNBLOCK:
p->p_sigmask &= ~(uap->mask);
#ifdef BSD_USE_APC
thread_apc_set(current_act(), bsd_ast);
#else
thread_ast_set(current_act(), AST_BSD);
ast_on(AST_BSD);
#endif
break;
case SIG_SETMASK:
p->p_sigmask = uap->mask &~ sigcantmask;
#ifdef BSD_USE_APC
thread_apc_set(current_act(), bsd_ast);
#else
thread_ast_set(current_act(), AST_BSD);
ast_on(AST_BSD);
#endif
break;
default:
error = EINVAL;
break;
}
(void) spl0();
return (error);
}
/* ARGSUSED */
int
sigpending(p, uap, retval)
struct proc *p;
void *uap;
register_t *retval;
{
*retval = p->p_siglist;
return (0);
}
#if COMPAT_43
/*
* Generalized interface signal handler, 4.3-compatible.
*/
struct osigvec_args {
int signum;
struct sigvec *nsv;
struct sigvec *osv;
};
/* ARGSUSED */
int
osigvec(p, uap, retval)
struct proc *p;
register struct osigvec_args *uap;
register_t *retval;
{
struct sigvec vec;
register struct sigacts *ps = p->p_sigacts;
register struct sigvec *sv;
register int signum;
int bit, error;
signum = uap->signum;
if (signum <= 0 || signum >= NSIG ||
signum == SIGKILL || signum == SIGSTOP)
return (EINVAL);
sv = &vec;
if (uap->osv) {
*(sig_t *)&sv->sv_handler = ps->ps_sigact[signum];
sv->sv_mask = ps->ps_catchmask[signum];
bit = sigmask(signum);
sv->sv_flags = 0;
if ((ps->ps_sigonstack & bit) != 0)
sv->sv_flags |= SV_ONSTACK;
if ((ps->ps_sigintr & bit) != 0)
sv->sv_flags |= SV_INTERRUPT;
if (p->p_flag & P_NOCLDSTOP)
sv->sv_flags |= SA_NOCLDSTOP;
if (error = copyout((caddr_t)sv, (caddr_t)uap->osv,
sizeof (vec)))
return (error);
}
if (uap->nsv) {
if (error = copyin((caddr_t)uap->nsv, (caddr_t)sv,
sizeof (vec)))
return (error);
sv->sv_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
setsigvec(p, signum, (struct sigaction *)sv);
}
return (0);
}
struct osigblock_args {
int mask;
};
int
osigblock(p, uap, retval)
register struct proc *p;
struct osigblock_args *uap;
register_t *retval;
{
(void) splhigh();
*retval = p->p_sigmask;
p->p_sigmask |= uap->mask &~ sigcantmask;
(void) spl0();
return (0);
}
struct osigsetmask_args {
int mask;
};
int
osigsetmask(p, uap, retval)
struct proc *p;
struct osigsetmask_args *uap;
register_t *retval;
{
(void) splhigh();
*retval = p->p_sigmask;
p->p_sigmask = uap->mask &~ sigcantmask;
(void) spl0();
return (0);
}
#endif /* COMPAT_43 */
/*
* 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.
*/
int
sigcontinue(error)
{
unix_syscall_return(EINTR);
}
struct sigsuspend_args {
int mask;
};
/* ARGSUSED */
int
sigsuspend(p, uap, retval)
register struct proc *p;
struct sigsuspend_args *uap;
register_t *retval;
{
register struct sigacts *ps = p->p_sigacts;
/*
* When returning from sigpause, 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.
*/
ps->ps_oldmask = p->p_sigmask;
ps->ps_flags |= SAS_OLDMASK;
p->p_sigmask = uap->mask &~ sigcantmask;
(void) tsleep0((caddr_t) p, PPAUSE|PCATCH, "pause", 0, sigcontinue);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
#if COMPAT_43
struct osigstack_args {
struct sigstack *nss;
struct sigstack *oss;
};
/* ARGSUSED */
int
osigstack(p, uap, retval)
struct proc *p;
register struct osigstack_args *uap;
register_t *retval;
{
struct sigstack ss;
struct sigacts *psp;
int error = 0;
psp = p->p_sigacts;
ss.ss_sp = psp->ps_sigstk.ss_sp;
ss.ss_onstack = psp->ps_sigstk.ss_flags & SA_ONSTACK;
if (uap->oss && (error = copyout((caddr_t)&ss,
(caddr_t)uap->oss, sizeof (struct sigstack))))
return (error);
if (uap->nss && (error = copyin((caddr_t)uap->nss,
(caddr_t)&ss, sizeof (ss))) == 0) {
psp->ps_sigstk.ss_sp = ss.ss_sp;
psp->ps_sigstk.ss_size = 0;
psp->ps_sigstk.ss_flags |= ss.ss_onstack & SA_ONSTACK;
psp->ps_flags |= SAS_ALTSTACK;
}
return (error);
}
#endif /* COMPAT_43 */
struct sigaltstack_args {
struct sigaltstack *nss;
struct sigaltstack *oss;
};
/* ARGSUSED */
int
sigaltstack(p, uap, retval)
struct proc *p;
register struct sigaltstack_args *uap;
register_t *retval;
{
struct sigacts *psp;
struct sigaltstack ss;
int error;
psp = p->p_sigacts;
if ((psp->ps_flags & SAS_ALTSTACK) == 0)
psp->ps_sigstk.ss_flags |= SA_DISABLE;
if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk,
(caddr_t)uap->oss, sizeof (struct sigaltstack))))
return (error);
if (uap->nss == 0)
return (0);
if (error = copyin((caddr_t)uap->nss, (caddr_t)&ss,
sizeof (ss)))
return (error);
if (ss.ss_flags & SA_DISABLE) {
if (psp->ps_sigstk.ss_flags & SA_ONSTACK)
return (EINVAL);
psp->ps_flags &= ~SAS_ALTSTACK;
psp->ps_sigstk.ss_flags = ss.ss_flags;
return (0);
}
if (ss.ss_size < MINSIGSTKSZ)
return (ENOMEM);
psp->ps_flags |= SAS_ALTSTACK;
psp->ps_sigstk= ss;
return (0);
}
struct kill_args {
int pid;
int signum;
};
/* ARGSUSED */
int
kill(cp, uap, retval)
register struct proc *cp;
register struct kill_args *uap;
register_t *retval;
{
register struct proc *p;
register struct pcred *pc = cp->p_cred;
if ((u_int)uap->signum >= NSIG)
return (EINVAL);
if (uap->pid > 0) {
/* kill single process */
if ((p = pfind(uap->pid)) == NULL)
return (ESRCH);
if (!cansignal(cp, pc, p, uap->signum))
return (EPERM);
if (uap->signum)
psignal(p, uap->signum);
return (0);
}
switch (uap->pid) {
case -1: /* broadcast signal */
return (killpg1(cp, uap->signum, 0, 1));
case 0: /* signal own process group */
return (killpg1(cp, uap->signum, 0, 0));
default: /* negative explicit process group */
return (killpg1(cp, uap->signum, -(uap->pid), 0));
}
/* NOTREACHED */
}
#if COMPAT_43
struct okillpg_args {
int pgid;
int signum;
};
/* ARGSUSED */
int
okillpg(p, uap, retval)
struct proc *p;
register struct okillpg_args *uap;
register_t *retval;
{
if ((u_int)uap->signum >= NSIG)
return (EINVAL);
return (killpg1(p, uap->signum, uap->pgid, 0));
}
#endif /* COMPAT_43 */
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
int
killpg1(cp, signum, pgid, all)
register struct proc *cp;
int signum, pgid, all;
{
register struct proc *p;
register struct pcred *pc = cp->p_cred;
struct pgrp *pgrp;
int nfound = 0;
if (all)
/*
* broadcast
*/
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p == cp || !cansignal(cp, pc, p, signum))
continue;
nfound++;
if (signum)
psignal(p, signum);
}
else {
if (pgid == 0)
/*
* zero pgid means send to my process group.
*/
pgrp = cp->p_pgrp;
else {
pgrp = pgfind(pgid);
if (pgrp == NULL)
return (ESRCH);
}
for (p = pgrp->pg_members.lh_first; p != 0;
p = p->p_pglist.le_next) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p->p_stat == SZOMB ||
!cansignal(cp, pc, p, signum))
continue;
nfound++;
if (signum)
psignal(p, signum);
}
}
return (nfound ? 0 : ESRCH);
}
/*
* Send a signal to a process group.
*/
void
gsignal(pgid, signum)
int pgid, signum;
{
struct pgrp *pgrp;
if (pgid && (pgrp = pgfind(pgid)))
pgsignal(pgrp, signum, 0);
}
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(pgrp, signum, checkctty)
struct pgrp *pgrp;
int signum, checkctty;
{
register struct proc *p;
if (pgrp)
for (p = pgrp->pg_members.lh_first; p != 0;
p = p->p_pglist.le_next)
if (checkctty == 0 || p->p_flag & P_CONTROLT)
psignal(p, signum);
}
/*
* Send a signal caused by a trap to a specific thread.
*/
void
threadsignal(sig_actthread, signum, code)
register thread_act_t *sig_actthread;
register int signum;
u_long code;
{
register struct uthread *uth;
register struct task * sig_task;
register struct proc *p ;
int mask;
if ((u_int)signum >= NSIG || signum == 0)
return;
mask = sigmask(signum);
if ((mask & threadmask) == 0)
return;
sig_task = get_threadtask(sig_actthread);
/* p = sig_task->proc; */
p = (struct proc *)(get_bsdtask_info(sig_task));
if (!(p->p_flag & P_TRACED) && (p->p_sigignore & mask))
return;
uth = get_bsdthread_info(sig_actthread);
simple_lock(&p->siglock);
uth->uu_sig |= mask;
uth->uu_code = code;
#ifdef BSD_USE_APC
thread_apc_set(sig_actthread, bsd_ast);
#else
thread_ast_set(sig_actthread,AST_BSD);
if (current_act() == sig_actthread)
ast_on(AST_BSD);
#endif
simple_unlock(&p->siglock);
}
/*
* 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, signum)
register struct proc *p;
register int signum;
{
register int s, prop;
register sig_t action;
register thread_act_t sig_thread_act;
register thread_t sig_thread;
register task_t sig_task;
register thread_t cur_thread;
thread_act_t *cur_act;
int mask;
if ((u_int)signum >= NSIG || signum == 0)
panic("psignal signal number");
mask = sigmask(signum);
prop = sigprop[signum];
/*
* We will need the task pointer later. Grab it now to
* check for a zombie process. Also don't send signals
* to kernel internal tasks.
*/
if (((sig_task = p->task) == TASK_NULL) || is_kerneltask(sig_task))
return;
/*
* If proc is traced, always give parent a chance.
*/
if (p->p_flag & P_TRACED)
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 (p->p_sigignore & mask)
return;
if (p->p_sigmask & mask)
action = SIG_HOLD;
else if (p->p_sigcatch & mask)
action = SIG_CATCH;
else
action = SIG_DFL;
}
if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
(p->p_flag & P_TRACED) == 0)
p->p_nice = NZERO;
if (prop & SA_CONT)
p->p_siglist &= ~stopsigmask;
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;
p->p_siglist &= ~contsigmask;
}
p->p_siglist |= mask;
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
return;
/*
* Deliver the signal to the first thread in the task. This
* allows single threaded applications which use signals to
* be able to be linked with multithreaded libraries. We have
* an implicit reference to the current_thread, but need
* an explicit one otherwise. The thread reference keeps
* the corresponding task data structures around too. This
* reference is released by thread_deallocate.
*/
s = splhigh();
cur_thread = current_thread(); /* this is a shuttle */
cur_act = current_act();
task_tllock(sig_task);
sig_thread_act = (thread_t) get_firstthread(sig_task);
if (sig_thread_act == THREAD_NULL) {
task_tlunlock(sig_task);
(void) splx(s);
return;
}
sig_thread = getshuttle_thread(sig_thread_act);
if (sig_thread == THREAD_NULL) {
printf("WARNING: valid act; but no shutte in psignal\n");
#if 0
/* FIXME : NO VALID SHUTTLE */
task_tlunlock(sig_task);
(void) splx(s);
return;
#endif
}
#ifdef BSD_USE_APC
thread_apc_set(sig_thread_act, bsd_ast);
#else
thread_ast_set(sig_thread_act,AST_BSD);
if (cur_act == sig_thread_act)
ast_on(AST_BSD);
#endif
/* #if FIXME */
if (sig_thread != cur_thread)
act_reference(sig_thread_act);
/* #endif */
task_tlunlock(sig_task);
/*
* SIGKILL priority twiddling moved here from above because
* it needs sig_thread. Could merge it into large switch
* below if we didn't care about priority for tracing
* as SIGKILL's action is always SIG_DFL.
*/
if ((signum == SIGKILL) && (p->p_nice > NZERO)) {
p->p_nice = NZERO;
#if FIXME /* [ */
thread_max_priority(sig_thread, sig_thread->processor_set,
BASEPRI_USER);
thread_priority(sig_thread, BASEPRI_USER, FALSE);
#endif /* FIXME ] */
}
/*
* Process is traced - wake it up (if not already
* stopped) so that it can discover the signal in
* issig() and stop for the parent.
*/
if (p->p_flag & P_TRACED) {
if (p->p_stat != SSTOP)
goto run;
else
goto out;
}
if (action != SIG_DFL) {
/*
* User wants to catch the signal.
* Wake up the thread, but don't un-suspend it
* (except for SIGCONT).
*/
if (prop & SA_CONT)
(void) task_resume(sig_task);
goto run;
} else {
/* Default action - varies */
if (mask & stopsigmask) {
/*
* These are the signals which by default
* stop a process.
*
* Don't clog system with children of init
* stopped from the keyboard.
*/
if (!(prop & SA_STOP) && p->p_pptr == initproc) {
psignal(p, SIGKILL);
p->p_siglist &= ~mask;
goto out;
}
/*
* Stop the task.
*/
if (!is_thread_running(sig_thread)) {
/* Thread is not running
* If task hasn't already been stopped by
* a signal, stop it.
*/
p->p_siglist &= ~mask;
if (get_task_userstop(sig_task) == 0) {
/*
* p_cursig must not be set, because
* it will be psig()'d if it is not
* zero, and the signal is being
* handled here. But save the signal
* in p_stopsig so WUNTRACED
* option to wait can find it.
*/
p->p_xstat = signum;
if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
psignal(p->p_pptr, SIGCHLD);
stop(p);
}
goto out;
} else {
if ((p == current_proc()) && (p->p_stat != SZOMB)) {
#ifdef BSD_USE_APC
thread_apc_set(cur_act, bsd_ast);
#else
thread_ast_set(cur_act, AST_BSD);
ast_on(AST_BSD);
#endif
}
goto out;
}
}
switch (signum) {
/*
* Signals ignored by default have been dealt
* with already, since their bits are on in
* p_sigignore.
*/
case SIGKILL:
/*
* Kill signal always sets process running and
* unsuspends it.
*/
while (get_task_userstop(sig_task) > 0)
(void) task_resume(sig_task);
/*
* Process will be running after 'run'
*/
p->p_stat = SRUN;
/*
* Break it out of user wait, as well.
*/
while (get_thread_userstop(sig_thread_act) > 0)
(void) thread_resume(sig_thread_act);
/*
* Clear system wait if possible.
*/
clear_wait(sig_thread, THREAD_INTERRUPTED, FALSE);
#if MACH_HOST
/*
* Make sure it can run.
*/
if (sig_thread->processor_set->empty)
thread_assign(sig_thread, &default_pset);
#endif
/*
* If we're delivering the signal to some other
* thread, that thread might be stuck in an
* exception. Break it out. Can't call
* thread_exception_abort from high spl, but
* SIGKILL can't be sent from interrupt level, so
* it's ok to drop spl. Can call thread_deallocate
* for same reason.
*/
splx(s);
if (sig_thread != cur_thread) {
thread_abort(sig_thread_act);
/* #if FIXME */
act_deallocate(sig_thread_act);
/* #endif */
}
return;
case SIGCONT:
/*
* Let the process run. If it's sleeping on an
* event, it remains so.
*/
(void) task_resume(sig_task);
p->p_stat = SRUN;
goto out;
default:
/*
* All other signals wake up the process, but don't
* resume it.
*/
goto run;
}
}
/*NOTREACHED*/
run:
/*
* If we're being traced (possibly because someone attached us
* while we were stopped), check for a signal from the debugger.
*/
if (p->p_stat == SSTOP) {
if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0)
p->p_siglist |= sigmask(p->p_xstat);
}
/*
* setrunnable(p) in BSD
*/
p->p_stat = SRUN;
/*
* Wake up the thread if it is interruptible.
*/
clear_wait(sig_thread, THREAD_INTERRUPTED, TRUE);
out:
splx(s);
/*** FIXME revisit this->who calls up ipc_thread_deallocate?? ***/
if (sig_thread != cur_thread)
act_deallocate(sig_thread_act);
}
__inline__ void
sig_lock_to_exit(
struct proc *p)
{
thread_t self = current_thread();
p->exit_thread = self;
simple_unlock(&p->siglock);
(void) task_hold(p->task);
(void) task_dowait(p->task, FALSE);
}
__inline__ int
sig_try_lock(
struct proc *p)
{
thread_t self = current_thread();
simple_lock(&p->siglock);
while (p->sigwait || p->exit_thread) {
simple_unlock(&p->siglock);
if (p->exit_thread) {
if (p->exit_thread == self) {
/*
* Already exiting - no signals.
*/
return 0;
}
else {
/*
* Another thread has called exit -
* stop (until terminate request).
*/
thread_hold(current_act());
}
}
if(assert_wait_possible()) {
assert_wait((caddr_t)&p->sigwait_thread, THREAD_UNINT);
}
thread_block(0);
if (thread_should_abort(self)) {
/*
* Terminate request - clean up.
*/
return -1;
}
simple_lock(&p->siglock);
}
return 1;
}
/*
* 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 the CURSIG macro.) The normal call
* sequence is
*
* while (signum = CURSIG(curproc))
* postsig(signum);
*/
int
issignal(p)
register struct proc *p;
{
register int signum, mask, prop, sigbits;
task_t task = p->task;
thread_act_t initial_threadact;
thread_t cur_thread;
thread_act_t cur_act;
int s;
struct uthread * ut;
#if DIAGNOSTIC
/*
* This must be called on master cpu
*/
if (cpu_number() != master_cpu)
panic("issig not on master");
#endif /* DIAGNOSTIC */
/*
* Try to grab the signal lock.
*/
if (sig_try_lock(p) <= 0)
return (0);
/*
* only allow delivery of process signals (asynchronous)
* to the initial thread. This is the first thread in
* the tasks thread list.
*/
initial_threadact = (thread_t)get_firstthread(task);
cur_thread = current_thread();
cur_act = current_act();
ut = get_bsdthread_info(cur_act);
for(;;) {
sigbits = (ut->uu_sig |p->p_siglist) & ~p->p_sigmask;
for (;;) {
if (p->p_flag & P_PPWAIT)
sigbits &= ~stopsigmask;
if (sigbits == 0) { /* no signal to send */
simple_unlock(&p->siglock);
return (0);
}
signum = ffs((long)sigbits);
mask = sigmask(signum);
prop = sigprop[signum];
if (mask & threadmask) {
/* we can take this signal */
ut->uu_sig &= ~mask;
break;
} else {
if (cur_act != initial_threadact)
sigbits &= ~mask;
else
break;
}
}
/*
* We should see pending but ignored signals
* only if P_TRACED was on when they were posted.
*/
if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) {
p->p_siglist &= ~mask; /* take the signal! */
continue;
}
if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
register int hold;
register task_t task;
/*
* If traced, always stop, and stay
* stopped until released by the debugger.
*/
if (p->p_flag & P_FSTRACE) {
#if PROCFS
/* procfs debugging */
p->p_stat = SSTOP;
wakeup((caddr_t)p);
#error need to implement
panic("procfs debugging");
#endif
} else {
#ifndef _WANT_GDB_TO_PANIC_
/*
* We may have already been assert_waited as
* part of a sleep, but we are going to
* subvert what we are sleeping on here.
* Since task_hold()/task_dowait() can
* block themselves, clear out the old
* condition here.
*/
clear_wait(cur_thread, THREAD_INTERRUPTED, FALSE);
#endif /* !_WANT_GDB_TO_PANIC_ */
/* ptrace debugging */
p->p_xstat = signum;
psignal(p->p_pptr, SIGCHLD);
pcb_synch(cur_thread);
/*
* XXX Have to really stop for debuggers;
* XXX stop() doesn't do the right thing.
* XXX Inline the task_suspend because we
* XXX have to diddle Unix state in the
* XXX middle of it.
*/
task = p->task;
hold = FALSE;
if (inc_task_userstop(task) == 0)
hold = TRUE;
if (hold) {
(void) task_hold(task);
act_reference(cur_act);
p->sigwait = TRUE;
p->sigwait_thread = cur_act;
simple_unlock(&p->siglock);
(void) task_dowait(task, TRUE);
}
else {
act_reference(cur_act);
p->sigwait = TRUE;
p->sigwait_thread = cur_act;
simple_unlock(&p->siglock);
}
p->p_stat = SSTOP;
p->p_flag &= ~P_WAITED;
p->p_siglist &= ~mask; /* clear the old signal */
wakeup((caddr_t)p->p_pptr);
assert_wait((caddr_t)&p->sigwait, THREAD_UNINT);
thread_block(0);
simple_lock(&p->siglock);
p->sigwait = FALSE;
p->sigwait_thread = NULL;
wakeup((caddr_t)&p->sigwait_thread);
act_deallocate(cur_act);
/*
* We get here only if task
* is continued or killed. Kill condition
* is signalled by adding NSIG to p_cursig.
* Pass original p_cursig as exit value in
* this case.
*/
if (p->p_siglist & sigmask(SIGKILL)) {
/*
* Wait event may still be outstanding;
* clear it, since sig_lock_to_exit will
* wait.
*/
clear_wait(current_thread(),
THREAD_INTERRUPTED,
FALSE);
sig_lock_to_exit(p);
/*
* Since this thread will be resumed
* to allow the current syscall to
* be completed, must save u_qsave
* before calling exit(). (Since exit()
* calls closef() which can trash u_qsave.)
*/
exit1(p,signum);
}
/*
* We may have to quit
*/
if (thread_should_abort(current_thread())) {
simple_unlock(&p->siglock);
return(0);
}
/*
* 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) {
if (mask & threadmask)
ut->uu_sig |= mask;
else
p->p_siglist |= mask;
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.
*/
signum = p->p_xstat;
if (signum == 0)
continue;
/*
* Put the new signal into p_siglist. If the
* signal is being masked, look for other signals.
*/
mask = sigmask(signum);
if (mask & threadmask)
ut->uu_sig |= mask;
else
p->p_siglist |= mask;
if (p->p_sigmask & mask)
continue;
}
}
/*
* Decide whether the signal should be returned.
* Return the signal's number, or fall through
* to clear it from the pending mask.
*/
switch ((long)p->p_sigacts->ps_sigact[signum]) {
case (long)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (p->p_pptr->p_pid == 0) {
#if DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %d) got signal %d\n",
p->p_pid, signum);
#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 = signum;
stop(p);
if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
psignal(p->p_pptr, SIGCHLD);
act_reference(cur_act);
p->sigwait = TRUE;
p->sigwait_thread = cur_act;
simple_unlock(&p->siglock);
thread_block(0);
simple_lock(&p->siglock);
p->sigwait = FALSE;
p->sigwait_thread = NULL;
wakeup((caddr_t)&p->sigwait_thread);
act_deallocate(cur_act);
/*
* We may have to quit
*/
if (thread_should_abort(current_thread())) {
simple_unlock(&p->siglock);
return(0);
}
break;
} else if (prop & SA_IGNORE) {
/*
* Except for SIGCONT, shouldn't get here.
* Default action is to ignore; drop it.
*/
break; /* == ignore */
} else {
simple_unlock(&p->siglock);
return (signum);
}
/*NOTREACHED*/
case (long)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.
*/
simple_unlock(&p->siglock);
return (signum);
}
p->p_siglist &= ~mask; /* 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.
*/
void
stop(p)
register struct proc *p;
{
/*
* Call special task_suspend routine,
* because this routine is called from interrupts
* (psignal) and cannot sleep.
*/
#ifdef FIXME
/* not clear why moving thread suspend matters*/
(void) task_suspend_nowait(p->task); /*XXX*/
p->p_stat = SSTOP;
p->p_flag &= ~P_WAITED;
wakeup((caddr_t)p->p_pptr);
#else
p->p_stat = SSTOP;
p->p_flag &= ~P_WAITED;
wakeup((caddr_t)p->p_pptr);
(void) task_suspend_nowait(p->task); /*XXX*/
#endif /* FIXME */
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(signum)
register int signum;
{
register struct proc *p = current_proc();
register struct sigacts *ps = p->p_sigacts;
register sig_t action;
u_long code;
int mask, returnmask;
#if DIAGNOSTIC
if (signum == 0)
panic("postsig");
/*
* This must be called on master cpu
*/
if (cpu_number() != master_cpu)
panic("psig not on master");
#endif
/*
* Try to grab the signal lock.
*/
if (sig_try_lock(p) <= 0)
return;
mask = sigmask(signum);
p->p_siglist &= ~mask;
action = ps->ps_sigact[signum];
#if KTRACE
if (KTRPOINT(p, KTR_PSIG))
ktrpsig(p->p_tracep,
signum, action, ps->ps_flags & SAS_OLDMASK ?
ps->ps_oldmask : p->p_sigmask, 0);
#endif
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
/* called with sig_lock() held */
sigexit(p, signum);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
#if DIAGNOSTIC
if (action == SIG_IGN || (p->p_sigmask & mask))
log(LOG_WARNING,
"postsig: processing masked or ignored signal\n");
#endif
/*
* Set the new mask value and also defer further
* occurences of this signal.
*
* Special case: user has done a sigpause. Here the
* current mask is not of interest, but rather the
* mask from before the sigpause is what we want
* restored after the signal processing is completed.
*/
(void) splhigh();
if (ps->ps_flags & SAS_OLDMASK) {
returnmask = ps->ps_oldmask;
ps->ps_flags &= ~SAS_OLDMASK;
} else
returnmask = p->p_sigmask;
p->p_sigmask |= ps->ps_catchmask[signum] | mask;
if (ps->ps_sig != signum) {
code = 0;
} else {
code = ps->ps_code;
ps->ps_code = 0;
}
simple_unlock(&p->siglock);
(void) spl0();
p->p_stats->p_ru.ru_nsignals++;
sendsig(p, action, signum, returnmask, code);
}
}
/*
* 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(p, signum)
register struct proc *p;
int signum;
{
sig_lock_to_exit(p);
p->p_acflag |= AXSIG;
if (sigprop[signum] & SA_CORE) {
p->p_sigacts->ps_sig = signum;
if (coredump(p) == 0)
signum |= WCOREFLAG;
}
exit1(p, W_EXITCODE(0, signum));
/* NOTREACHED */
}
void
bsd_ast(thread_act_t thr_act)
{
struct proc *p = current_proc();
struct uthread *ut = get_bsdthread_info(thr_act);
int signum;
unsigned int pc;
boolean_t funnel_state;
if (p == NULL)
return;
funnel_state = thread_set_funneled(TRUE);
if ((p->p_flag & P_OWEUPC) && (p->p_flag & P_PROFIL)) {
pc = get_useraddr();
addupc_task(p, pc, 1);
p->p_flag &= ~P_OWEUPC;
}
if (CHECK_SIGNALS(p, current_thread(), ut)) {
while (signum = issignal(p))
postsig(signum);
}
#ifdef BSD_USE_APC
thread_apc_clear(thr_act, bsd_ast);
#else
ast_off(AST_BSD);
#endif
(void) thread_set_funneled(funnel_state);
}