FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_sig.c
1 /*
2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.26.2.3 1999/09/05 08:15:03 peter Exp $
40 */
41
42 #include "opt_ktrace.h"
43
44 #define SIGPROP /* include signal properties table */
45 #include <sys/param.h>
46 #include <sys/sysproto.h>
47 #include <sys/signalvar.h>
48 #include <sys/resourcevar.h>
49 #include <sys/namei.h>
50 #include <sys/vnode.h>
51 #include <sys/proc.h>
52 #include <sys/systm.h>
53 #include <sys/timeb.h>
54 #include <sys/times.h>
55 #include <sys/buf.h>
56 #include <sys/acct.h>
57 #include <sys/file.h>
58 #include <sys/kernel.h>
59 #include <sys/wait.h>
60 #include <sys/ktrace.h>
61 #include <sys/syslog.h>
62 #include <sys/stat.h>
63 #include <sys/sysent.h>
64
65 #include <machine/cpu.h>
66
67 #include <vm/vm.h>
68 #include <vm/vm_param.h>
69 #include <vm/vm_prot.h>
70 #include <vm/lock.h>
71 #include <vm/pmap.h>
72 #include <vm/vm_map.h>
73 #include <sys/user.h> /* for coredump */
74
75 static int coredump __P((struct proc *p));
76 static int killpg1 __P((struct proc *cp, int signum, int pgid, int all));
77 static void stop __P((struct proc *));
78
79 /*
80 * Can process p, with pcred pc, send the signal signum to process q?
81 */
82 #define CANSIGNAL(p, pc, q, signum) \
83 ((pc)->pc_ucred->cr_uid == 0 || \
84 (pc)->p_ruid == (q)->p_cred->p_ruid || \
85 (pc)->pc_ucred->cr_uid == (q)->p_cred->p_ruid || \
86 (pc)->p_ruid == (q)->p_ucred->cr_uid || \
87 (pc)->pc_ucred->cr_uid == (q)->p_ucred->cr_uid || \
88 ((signum) == SIGCONT && (q)->p_session == (p)->p_session))
89
90 #ifndef _SYS_SYSPROTO_H_
91 struct sigaction_args {
92 int signum;
93 struct sigaction *nsa;
94 struct sigaction *osa;
95 };
96 #endif
97 /* ARGSUSED */
98 int
99 sigaction(p, uap, retval)
100 struct proc *p;
101 register struct sigaction_args *uap;
102 int *retval;
103 {
104 struct sigaction vec;
105 register struct sigaction *sa;
106 register struct sigacts *ps = p->p_sigacts;
107 register int signum;
108 int bit, error;
109
110 signum = uap->signum;
111 if (signum <= 0 || signum >= NSIG)
112 return (EINVAL);
113 sa = &vec;
114 if (uap->osa) {
115 sa->sa_handler = ps->ps_sigact[signum];
116 sa->sa_mask = ps->ps_catchmask[signum];
117 bit = sigmask(signum);
118 sa->sa_flags = 0;
119 if ((ps->ps_sigonstack & bit) != 0)
120 sa->sa_flags |= SA_ONSTACK;
121 if ((ps->ps_sigintr & bit) == 0)
122 sa->sa_flags |= SA_RESTART;
123 if ((ps->ps_sigreset & bit) != 0)
124 sa->sa_flags |= SA_RESETHAND;
125 if ((ps->ps_signodefer & bit) != 0)
126 sa->sa_flags |= SA_NODEFER;
127 if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP)
128 sa->sa_flags |= SA_NOCLDSTOP;
129 if ((error = copyout((caddr_t)sa, (caddr_t)uap->osa,
130 sizeof (vec))))
131 return (error);
132 }
133 if (uap->nsa) {
134 if ((error = copyin((caddr_t)uap->nsa, (caddr_t)sa,
135 sizeof (vec))))
136 return (error);
137 if ((signum == SIGKILL || signum == SIGSTOP) &&
138 sa->sa_handler != SIG_DFL)
139 return (EINVAL);
140 setsigvec(p, signum, sa);
141 }
142 return (0);
143 }
144
145 void
146 setsigvec(p, signum, sa)
147 register struct proc *p;
148 int signum;
149 register struct sigaction *sa;
150 {
151 register struct sigacts *ps = p->p_sigacts;
152 register int bit;
153
154 bit = sigmask(signum);
155 /*
156 * Change setting atomically.
157 */
158 (void) splhigh();
159 ps->ps_sigact[signum] = sa->sa_handler;
160 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
161 if ((sa->sa_flags & SA_RESTART) == 0)
162 ps->ps_sigintr |= bit;
163 else
164 ps->ps_sigintr &= ~bit;
165 if (sa->sa_flags & SA_ONSTACK)
166 ps->ps_sigonstack |= bit;
167 else
168 ps->ps_sigonstack &= ~bit;
169 if (sa->sa_flags & SA_RESETHAND)
170 ps->ps_sigreset |= bit;
171 else
172 ps->ps_sigreset &= ~bit;
173 if (sa->sa_flags & SA_NODEFER)
174 ps->ps_signodefer |= bit;
175 else
176 ps->ps_signodefer &= ~bit;
177 #ifdef COMPAT_SUNOS
178 if (sa->sa_flags & SA_USERTRAMP)
179 ps->ps_usertramp |= bit;
180 else
181 ps->ps_usertramp &= ~bit;
182 #endif
183 if (signum == SIGCHLD) {
184 if (sa->sa_flags & SA_NOCLDSTOP)
185 p->p_flag |= P_NOCLDSTOP;
186 else
187 p->p_flag &= ~P_NOCLDSTOP;
188 }
189 /*
190 * Set bit in p_sigignore for signals that are set to SIG_IGN,
191 * and for signals set to SIG_DFL where the default is to ignore.
192 * However, don't put SIGCONT in p_sigignore,
193 * as we have to restart the process.
194 */
195 if (sa->sa_handler == SIG_IGN ||
196 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
197 p->p_siglist &= ~bit; /* never to be seen again */
198 if (signum != SIGCONT)
199 p->p_sigignore |= bit; /* easier in psignal */
200 p->p_sigcatch &= ~bit;
201 } else {
202 p->p_sigignore &= ~bit;
203 if (sa->sa_handler == SIG_DFL)
204 p->p_sigcatch &= ~bit;
205 else
206 p->p_sigcatch |= bit;
207 }
208 (void) spl0();
209 }
210
211 /*
212 * Initialize signal state for process 0;
213 * set to ignore signals that are ignored by default.
214 */
215 void
216 siginit(p)
217 struct proc *p;
218 {
219 register int i;
220
221 for (i = 0; i < NSIG; i++)
222 if (sigprop[i] & SA_IGNORE && i != SIGCONT)
223 p->p_sigignore |= sigmask(i);
224 }
225
226 /*
227 * Reset signals for an exec of the specified process.
228 */
229 void
230 execsigs(p)
231 register struct proc *p;
232 {
233 register struct sigacts *ps = p->p_sigacts;
234 register int nc, mask;
235
236 /*
237 * Reset caught signals. Held signals remain held
238 * through p_sigmask (unless they were caught,
239 * and are now ignored by default).
240 */
241 while (p->p_sigcatch) {
242 nc = ffs((long)p->p_sigcatch);
243 mask = sigmask(nc);
244 p->p_sigcatch &= ~mask;
245 if (sigprop[nc] & SA_IGNORE) {
246 if (nc != SIGCONT)
247 p->p_sigignore |= mask;
248 p->p_siglist &= ~mask;
249 }
250 ps->ps_sigact[nc] = SIG_DFL;
251 }
252 /*
253 * Reset stack state to the user stack.
254 * Clear set of signals caught on the signal stack.
255 */
256 ps->ps_sigstk.ss_flags = SS_DISABLE;
257 ps->ps_sigstk.ss_size = 0;
258 ps->ps_sigstk.ss_sp = 0;
259 ps->ps_flags = 0;
260 }
261
262 /*
263 * Manipulate signal mask.
264 * Note that we receive new mask, not pointer,
265 * and return old mask as return value;
266 * the library stub does the rest.
267 */
268 #ifndef _SYS_SYSPROTO_H_
269 struct sigprocmask_args {
270 int how;
271 sigset_t mask;
272 };
273 #endif
274 int
275 sigprocmask(p, uap, retval)
276 register struct proc *p;
277 struct sigprocmask_args *uap;
278 int *retval;
279 {
280 int error = 0;
281
282 *retval = p->p_sigmask;
283 (void) splhigh();
284
285 switch (uap->how) {
286 case SIG_BLOCK:
287 p->p_sigmask |= uap->mask &~ sigcantmask;
288 break;
289
290 case SIG_UNBLOCK:
291 p->p_sigmask &= ~uap->mask;
292 break;
293
294 case SIG_SETMASK:
295 p->p_sigmask = uap->mask &~ sigcantmask;
296 break;
297
298 default:
299 error = EINVAL;
300 break;
301 }
302 (void) spl0();
303 return (error);
304 }
305
306 #ifndef _SYS_SYSPROTO_H_
307 struct sigpending_args {
308 int dummy;
309 };
310 #endif
311 /* ARGSUSED */
312 int
313 sigpending(p, uap, retval)
314 struct proc *p;
315 struct sigpending_args *uap;
316 int *retval;
317 {
318
319 *retval = p->p_siglist;
320 return (0);
321 }
322
323 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
324 /*
325 * Generalized interface signal handler, 4.3-compatible.
326 */
327 #ifndef _SYS_SYSPROTO_H_
328 struct osigvec_args {
329 int signum;
330 struct sigvec *nsv;
331 struct sigvec *osv;
332 };
333 #endif
334 /* ARGSUSED */
335 int
336 osigvec(p, uap, retval)
337 struct proc *p;
338 register struct osigvec_args *uap;
339 int *retval;
340 {
341 struct sigvec vec;
342 register struct sigacts *ps = p->p_sigacts;
343 register struct sigvec *sv;
344 register int signum;
345 int bit, error;
346
347 signum = uap->signum;
348 if (signum <= 0 || signum >= NSIG)
349 return (EINVAL);
350 sv = &vec;
351 if (uap->osv) {
352 *(sig_t *)&sv->sv_handler = ps->ps_sigact[signum];
353 sv->sv_mask = ps->ps_catchmask[signum];
354 bit = sigmask(signum);
355 sv->sv_flags = 0;
356 if ((ps->ps_sigonstack & bit) != 0)
357 sv->sv_flags |= SV_ONSTACK;
358 if ((ps->ps_sigintr & bit) != 0)
359 sv->sv_flags |= SV_INTERRUPT;
360 if ((ps->ps_sigreset & bit) != 0)
361 sv->sv_flags |= SV_RESETHAND;
362 if ((ps->ps_signodefer & bit) != 0)
363 sv->sv_flags |= SV_NODEFER;
364 #ifndef COMPAT_SUNOS
365 if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP)
366 sv->sv_flags |= SV_NOCLDSTOP;
367 #endif
368 if ((error = copyout((caddr_t)sv, (caddr_t)uap->osv,
369 sizeof (vec))))
370 return (error);
371 }
372 if (uap->nsv) {
373 if ((error = copyin((caddr_t)uap->nsv, (caddr_t)sv,
374 sizeof (vec))))
375 return (error);
376 if ((signum == SIGKILL || signum == SIGSTOP) &&
377 sv->sv_handler != SIG_DFL)
378 return (EINVAL);
379 #ifdef COMPAT_SUNOS
380 sv->sv_flags |= SA_USERTRAMP;
381 #endif
382 sv->sv_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
383 setsigvec(p, signum, (struct sigaction *)sv);
384 }
385 return (0);
386 }
387
388 #ifndef _SYS_SYSPROTO_H_
389 struct osigblock_args {
390 int mask;
391 };
392 #endif
393 int
394 osigblock(p, uap, retval)
395 register struct proc *p;
396 struct osigblock_args *uap;
397 int *retval;
398 {
399
400 (void) splhigh();
401 *retval = p->p_sigmask;
402 p->p_sigmask |= uap->mask &~ sigcantmask;
403 (void) spl0();
404 return (0);
405 }
406
407 #ifndef _SYS_SYSPROTO_H_
408 struct osigsetmask_args {
409 int mask;
410 };
411 #endif
412 int
413 osigsetmask(p, uap, retval)
414 struct proc *p;
415 struct osigsetmask_args *uap;
416 int *retval;
417 {
418
419 (void) splhigh();
420 *retval = p->p_sigmask;
421 p->p_sigmask = uap->mask &~ sigcantmask;
422 (void) spl0();
423 return (0);
424 }
425 #endif /* COMPAT_43 || COMPAT_SUNOS */
426
427 /*
428 * Suspend process until signal, providing mask to be set
429 * in the meantime. Note nonstandard calling convention:
430 * libc stub passes mask, not pointer, to save a copyin.
431 */
432 #ifndef _SYS_SYSPROTO_H_
433 struct sigsuspend_args {
434 sigset_t mask;
435 };
436 #endif
437 /* ARGSUSED */
438 int
439 sigsuspend(p, uap, retval)
440 register struct proc *p;
441 struct sigsuspend_args *uap;
442 int *retval;
443 {
444 register struct sigacts *ps = p->p_sigacts;
445
446 /*
447 * When returning from sigpause, we want
448 * the old mask to be restored after the
449 * signal handler has finished. Thus, we
450 * save it here and mark the sigacts structure
451 * to indicate this.
452 */
453 ps->ps_oldmask = p->p_sigmask;
454 ps->ps_flags |= SAS_OLDMASK;
455 p->p_sigmask = uap->mask &~ sigcantmask;
456 while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0)
457 /* void */;
458 /* always return EINTR rather than ERESTART... */
459 return (EINTR);
460 }
461
462 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
463 #ifndef _SYS_SYSPROTO_H_
464 struct osigstack_args {
465 struct sigstack *nss;
466 struct sigstack *oss;
467 };
468 #endif
469 /* ARGSUSED */
470 int
471 osigstack(p, uap, retval)
472 struct proc *p;
473 register struct osigstack_args *uap;
474 int *retval;
475 {
476 struct sigstack ss;
477 struct sigacts *psp;
478 int error = 0;
479
480 psp = p->p_sigacts;
481 ss.ss_sp = psp->ps_sigstk.ss_sp;
482 ss.ss_onstack = psp->ps_sigstk.ss_flags & SS_ONSTACK;
483 if (uap->oss && (error = copyout((caddr_t)&ss, (caddr_t)uap->oss,
484 sizeof (struct sigstack))))
485 return (error);
486 if (uap->nss && (error = copyin((caddr_t)uap->nss, (caddr_t)&ss,
487 sizeof (ss))) == 0) {
488 psp->ps_sigstk.ss_sp = ss.ss_sp;
489 psp->ps_sigstk.ss_size = 0;
490 psp->ps_sigstk.ss_flags |= ss.ss_onstack & SS_ONSTACK;
491 psp->ps_flags |= SAS_ALTSTACK;
492 }
493 return (error);
494 }
495 #endif /* COMPAT_43 || COMPAT_SUNOS */
496
497 #ifndef _SYS_SYSPROTO_H_
498 struct sigaltstack_args {
499 struct sigaltstack *nss;
500 struct sigaltstack *oss;
501 };
502 #endif
503 /* ARGSUSED */
504 int
505 sigaltstack(p, uap, retval)
506 struct proc *p;
507 register struct sigaltstack_args *uap;
508 int *retval;
509 {
510 struct sigacts *psp;
511 struct sigaltstack ss;
512 int error;
513
514 psp = p->p_sigacts;
515 if ((psp->ps_flags & SAS_ALTSTACK) == 0)
516 psp->ps_sigstk.ss_flags |= SS_DISABLE;
517 if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk,
518 (caddr_t)uap->oss, sizeof (struct sigaltstack))))
519 return (error);
520 if (uap->nss == 0)
521 return (0);
522 if ((error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss))))
523 return (error);
524 if (ss.ss_flags & SS_DISABLE) {
525 if (psp->ps_sigstk.ss_flags & SS_ONSTACK)
526 return (EINVAL);
527 psp->ps_flags &= ~SAS_ALTSTACK;
528 psp->ps_sigstk.ss_flags = ss.ss_flags;
529 return (0);
530 }
531 if (ss.ss_size < MINSIGSTKSZ)
532 return (ENOMEM);
533 psp->ps_flags |= SAS_ALTSTACK;
534 psp->ps_sigstk= ss;
535 return (0);
536 }
537
538 /*
539 * Common code for kill process group/broadcast kill.
540 * cp is calling process.
541 */
542 int
543 killpg1(cp, signum, pgid, all)
544 register struct proc *cp;
545 int signum, pgid, all;
546 {
547 register struct proc *p;
548 register struct pcred *pc = cp->p_cred;
549 struct pgrp *pgrp;
550 int nfound = 0;
551
552 if (all)
553 /*
554 * broadcast
555 */
556 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
557 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
558 p == cp || !CANSIGNAL(cp, pc, p, signum))
559 continue;
560 nfound++;
561 if (signum)
562 psignal(p, signum);
563 }
564 else {
565 if (pgid == 0)
566 /*
567 * zero pgid means send to my process group.
568 */
569 pgrp = cp->p_pgrp;
570 else {
571 pgrp = pgfind(pgid);
572 if (pgrp == NULL)
573 return (ESRCH);
574 }
575 for (p = pgrp->pg_members.lh_first; p != 0;
576 p = p->p_pglist.le_next) {
577 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
578 p->p_stat == SZOMB ||
579 !CANSIGNAL(cp, pc, p, signum))
580 continue;
581 nfound++;
582 if (signum)
583 psignal(p, signum);
584 }
585 }
586 return (nfound ? 0 : ESRCH);
587 }
588
589 #ifndef _SYS_SYSPROTO_H_
590 struct kill_args {
591 int pid;
592 int signum;
593 };
594 #endif
595 /* ARGSUSED */
596 int
597 kill(cp, uap, retval)
598 register struct proc *cp;
599 register struct kill_args *uap;
600 int *retval;
601 {
602 register struct proc *p;
603 register struct pcred *pc = cp->p_cred;
604
605 if ((u_int)uap->signum >= NSIG)
606 return (EINVAL);
607 if (uap->pid > 0) {
608 /* kill single process */
609 if ((p = pfind(uap->pid)) == NULL)
610 return (ESRCH);
611 if (!CANSIGNAL(cp, pc, p, uap->signum))
612 return (EPERM);
613 if (uap->signum)
614 psignal(p, uap->signum);
615 return (0);
616 }
617 switch (uap->pid) {
618 case -1: /* broadcast signal */
619 return (killpg1(cp, uap->signum, 0, 1));
620 case 0: /* signal own process group */
621 return (killpg1(cp, uap->signum, 0, 0));
622 default: /* negative explicit process group */
623 return (killpg1(cp, uap->signum, -uap->pid, 0));
624 }
625 /* NOTREACHED */
626 }
627
628 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
629 #ifndef _SYS_SYSPROTO_H_
630 struct okillpg_args {
631 int pgid;
632 int signum;
633 };
634 #endif
635 /* ARGSUSED */
636 int
637 okillpg(p, uap, retval)
638 struct proc *p;
639 register struct okillpg_args *uap;
640 int *retval;
641 {
642
643 if ((u_int)uap->signum >= NSIG)
644 return (EINVAL);
645 return (killpg1(p, uap->signum, uap->pgid, 0));
646 }
647 #endif /* COMPAT_43 || COMPAT_SUNOS */
648
649 /*
650 * Send a signal to a process group.
651 */
652 void
653 gsignal(pgid, signum)
654 int pgid, signum;
655 {
656 struct pgrp *pgrp;
657
658 if (pgid && (pgrp = pgfind(pgid)))
659 pgsignal(pgrp, signum, 0);
660 }
661
662 /*
663 * Send a signal to a process group. If checktty is 1,
664 * limit to members which have a controlling terminal.
665 */
666 void
667 pgsignal(pgrp, signum, checkctty)
668 struct pgrp *pgrp;
669 int signum, checkctty;
670 {
671 register struct proc *p;
672
673 if (pgrp)
674 for (p = pgrp->pg_members.lh_first; p != 0;
675 p = p->p_pglist.le_next)
676 if (checkctty == 0 || p->p_flag & P_CONTROLT)
677 psignal(p, signum);
678 }
679
680 /*
681 * Send a signal caused by a trap to the current process.
682 * If it will be caught immediately, deliver it with correct code.
683 * Otherwise, post it normally.
684 */
685 void
686 trapsignal(p, signum, code)
687 struct proc *p;
688 register int signum;
689 u_long code;
690 {
691 register struct sigacts *ps = p->p_sigacts;
692 int mask;
693
694 mask = sigmask(signum);
695 if ((p->p_flag & P_TRACED) == 0 && (p->p_sigcatch & mask) != 0 &&
696 (p->p_sigmask & mask) == 0) {
697 p->p_stats->p_ru.ru_nsignals++;
698 #ifdef KTRACE
699 if (KTRPOINT(p, KTR_PSIG))
700 ktrpsig(p->p_tracep, signum, ps->ps_sigact[signum],
701 p->p_sigmask, code);
702 #endif
703 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[signum], signum,
704 p->p_sigmask, code);
705 p->p_sigmask |= ps->ps_catchmask[signum] |
706 (mask & ~ps->ps_signodefer);
707 if ((ps->ps_sigreset & mask) != 0) {
708 /*
709 * See setsigvec() for origin of this code.
710 */
711 p->p_sigcatch &= ~mask;
712 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
713 p->p_sigignore |= mask;
714 ps->ps_sigact[signum] = SIG_DFL;
715 }
716 } else {
717 ps->ps_code = code; /* XXX for core dump/debugger */
718 ps->ps_sig = signum; /* XXX to verify code */
719 psignal(p, signum);
720 }
721 }
722
723 /*
724 * Send the signal to the process. If the signal has an action, the action
725 * is usually performed by the target process rather than the caller; we add
726 * the signal to the set of pending signals for the process.
727 *
728 * Exceptions:
729 * o When a stop signal is sent to a sleeping process that takes the
730 * default action, the process is stopped without awakening it.
731 * o SIGCONT restarts stopped processes (or puts them back to sleep)
732 * regardless of the signal action (eg, blocked or ignored).
733 *
734 * Other ignored signals are discarded immediately.
735 */
736 void
737 psignal(p, signum)
738 register struct proc *p;
739 register int signum;
740 {
741 register int s, prop;
742 register sig_t action;
743 int mask;
744
745 if ((u_int)signum >= NSIG || signum == 0)
746 panic("psignal signal number");
747 mask = sigmask(signum);
748 prop = sigprop[signum];
749
750 /*
751 * If proc is traced, always give parent a chance.
752 */
753 if (p->p_flag & P_TRACED)
754 action = SIG_DFL;
755 else {
756 /*
757 * If the signal is being ignored,
758 * then we forget about it immediately.
759 * (Note: we don't set SIGCONT in p_sigignore,
760 * and if it is set to SIG_IGN,
761 * action will be SIG_DFL here.)
762 */
763 if (p->p_sigignore & mask)
764 return;
765 if (p->p_sigmask & mask)
766 action = SIG_HOLD;
767 else if (p->p_sigcatch & mask)
768 action = SIG_CATCH;
769 else
770 action = SIG_DFL;
771 }
772
773 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
774 (p->p_flag & P_TRACED) == 0)
775 p->p_nice = NZERO;
776
777 if (prop & SA_CONT)
778 p->p_siglist &= ~stopsigmask;
779
780 if (prop & SA_STOP) {
781 /*
782 * If sending a tty stop signal to a member of an orphaned
783 * process group, discard the signal here if the action
784 * is default; don't stop the process below if sleeping,
785 * and don't clear any pending SIGCONT.
786 */
787 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
788 action == SIG_DFL)
789 return;
790 p->p_siglist &= ~contsigmask;
791 }
792 p->p_siglist |= mask;
793
794 /*
795 * Defer further processing for signals which are held,
796 * except that stopped processes must be continued by SIGCONT.
797 */
798 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
799 return;
800 s = splhigh();
801 switch (p->p_stat) {
802
803 case SSLEEP:
804 /*
805 * If process is sleeping uninterruptibly
806 * we can't interrupt the sleep... the signal will
807 * be noticed when the process returns through
808 * trap() or syscall().
809 */
810 if ((p->p_flag & P_SINTR) == 0)
811 goto out;
812 /*
813 * Process is sleeping and traced... make it runnable
814 * so it can discover the signal in issignal() and stop
815 * for the parent.
816 */
817 if (p->p_flag & P_TRACED)
818 goto run;
819 /*
820 * If SIGCONT is default (or ignored) and process is
821 * asleep, we are finished; the process should not
822 * be awakened.
823 */
824 if ((prop & SA_CONT) && action == SIG_DFL) {
825 p->p_siglist &= ~mask;
826 goto out;
827 }
828 /*
829 * When a sleeping process receives a stop
830 * signal, process immediately if possible.
831 * All other (caught or default) signals
832 * cause the process to run.
833 */
834 if (prop & SA_STOP) {
835 if (action != SIG_DFL)
836 goto runfast;
837 /*
838 * If a child holding parent blocked,
839 * stopping could cause deadlock.
840 */
841 if (p->p_flag & P_PPWAIT)
842 goto out;
843 p->p_siglist &= ~mask;
844 p->p_xstat = signum;
845 if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
846 psignal(p->p_pptr, SIGCHLD);
847 stop(p);
848 goto out;
849 } else
850 goto runfast;
851 /*NOTREACHED*/
852
853 case SSTOP:
854 /*
855 * If traced process is already stopped,
856 * then no further action is necessary.
857 */
858 if (p->p_flag & P_TRACED)
859 goto out;
860
861 /*
862 * Kill signal always sets processes running.
863 */
864 if (signum == SIGKILL)
865 goto runfast;
866
867 if (prop & SA_CONT) {
868 /*
869 * If SIGCONT is default (or ignored), we continue the
870 * process but don't leave the signal in p_siglist, as
871 * it has no further action. If SIGCONT is held, we
872 * continue the process and leave the signal in
873 * p_siglist. If the process catches SIGCONT, let it
874 * handle the signal itself. If it isn't waiting on
875 * an event, then it goes back to run state.
876 * Otherwise, process goes back to sleep state.
877 */
878 if (action == SIG_DFL)
879 p->p_siglist &= ~mask;
880 if (action == SIG_CATCH)
881 goto runfast;
882 if (p->p_wchan == 0)
883 goto run;
884 p->p_stat = SSLEEP;
885 goto out;
886 }
887
888 if (prop & SA_STOP) {
889 /*
890 * Already stopped, don't need to stop again.
891 * (If we did the shell could get confused.)
892 */
893 p->p_siglist &= ~mask; /* take it away */
894 goto out;
895 }
896
897 /*
898 * If process is sleeping interruptibly, then simulate a
899 * wakeup so that when it is continued, it will be made
900 * runnable and can look at the signal. But don't make
901 * the process runnable, leave it stopped.
902 */
903 if (p->p_wchan && p->p_flag & P_SINTR)
904 unsleep(p);
905 goto out;
906
907 default:
908 /*
909 * SRUN, SIDL, SZOMB do nothing with the signal,
910 * other than kicking ourselves if we are running.
911 * It will either never be noticed, or noticed very soon.
912 */
913 if (p == curproc)
914 signotify(p);
915 goto out;
916 }
917 /*NOTREACHED*/
918
919 runfast:
920 /*
921 * Raise priority to at least PUSER.
922 */
923 if (p->p_priority > PUSER)
924 p->p_priority = PUSER;
925 run:
926 setrunnable(p);
927 out:
928 splx(s);
929 }
930
931 /*
932 * If the current process has received a signal (should be caught or cause
933 * termination, should interrupt current syscall), return the signal number.
934 * Stop signals with default action are processed immediately, then cleared;
935 * they aren't returned. This is checked after each entry to the system for
936 * a syscall or trap (though this can usually be done without calling issignal
937 * by checking the pending signal masks in the CURSIG macro.) The normal call
938 * sequence is
939 *
940 * while (signum = CURSIG(curproc))
941 * postsig(signum);
942 */
943 int
944 issignal(p)
945 register struct proc *p;
946 {
947 register int signum, mask, prop;
948
949 for (;;) {
950 mask = p->p_siglist & ~p->p_sigmask;
951 if (p->p_flag & P_PPWAIT)
952 mask &= ~stopsigmask;
953 if (mask == 0) /* no signal to send */
954 return (0);
955 signum = ffs((long)mask);
956 mask = sigmask(signum);
957 prop = sigprop[signum];
958 /*
959 * We should see pending but ignored signals
960 * only if P_TRACED was on when they were posted.
961 */
962 if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) {
963 p->p_siglist &= ~mask;
964 continue;
965 }
966 if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
967 /*
968 * If traced, always stop, and stay
969 * stopped until released by the parent.
970 */
971 p->p_xstat = signum;
972 psignal(p->p_pptr, SIGCHLD);
973 do {
974 stop(p);
975 mi_switch();
976 } while (!trace_req(p) && p->p_flag & P_TRACED);
977
978 /*
979 * If the traced bit got turned off, go back up
980 * to the top to rescan signals. This ensures
981 * that p_sig* and ps_sigact are consistent.
982 */
983 if ((p->p_flag & P_TRACED) == 0)
984 continue;
985
986 /*
987 * If parent wants us to take the signal,
988 * then it will leave it in p->p_xstat;
989 * otherwise we just look for signals again.
990 */
991 p->p_siglist &= ~mask; /* clear the old signal */
992 signum = p->p_xstat;
993 if (signum == 0)
994 continue;
995
996 /*
997 * Put the new signal into p_siglist. If the
998 * signal is being masked, look for other signals.
999 */
1000 mask = sigmask(signum);
1001 p->p_siglist |= mask;
1002 if (p->p_sigmask & mask)
1003 continue;
1004 }
1005
1006 /*
1007 * Decide whether the signal should be returned.
1008 * Return the signal's number, or fall through
1009 * to clear it from the pending mask.
1010 */
1011 switch ((int)p->p_sigacts->ps_sigact[signum]) {
1012
1013 case (int)SIG_DFL:
1014 /*
1015 * Don't take default actions on system processes.
1016 */
1017 if (p->p_pid <= 1) {
1018 #ifdef DIAGNOSTIC
1019 /*
1020 * Are you sure you want to ignore SIGSEGV
1021 * in init? XXX
1022 */
1023 printf("Process (pid %lu) got signal %d\n",
1024 (u_long)p->p_pid, signum);
1025 #endif
1026 break; /* == ignore */
1027 }
1028 /*
1029 * If there is a pending stop signal to process
1030 * with default action, stop here,
1031 * then clear the signal. However,
1032 * if process is member of an orphaned
1033 * process group, ignore tty stop signals.
1034 */
1035 if (prop & SA_STOP) {
1036 if (p->p_flag & P_TRACED ||
1037 (p->p_pgrp->pg_jobc == 0 &&
1038 prop & SA_TTYSTOP))
1039 break; /* == ignore */
1040 p->p_xstat = signum;
1041 stop(p);
1042 if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
1043 psignal(p->p_pptr, SIGCHLD);
1044 mi_switch();
1045 break;
1046 } else if (prop & SA_IGNORE) {
1047 /*
1048 * Except for SIGCONT, shouldn't get here.
1049 * Default action is to ignore; drop it.
1050 */
1051 break; /* == ignore */
1052 } else
1053 return (signum);
1054 /*NOTREACHED*/
1055
1056 case (int)SIG_IGN:
1057 /*
1058 * Masking above should prevent us ever trying
1059 * to take action on an ignored signal other
1060 * than SIGCONT, unless process is traced.
1061 */
1062 if ((prop & SA_CONT) == 0 &&
1063 (p->p_flag & P_TRACED) == 0)
1064 printf("issignal\n");
1065 break; /* == ignore */
1066
1067 default:
1068 /*
1069 * This signal has an action, let
1070 * postsig() process it.
1071 */
1072 return (signum);
1073 }
1074 p->p_siglist &= ~mask; /* take the signal! */
1075 }
1076 /* NOTREACHED */
1077 }
1078
1079 /*
1080 * Put the argument process into the stopped state and notify the parent
1081 * via wakeup. Signals are handled elsewhere. The process must not be
1082 * on the run queue.
1083 */
1084 void
1085 stop(p)
1086 register struct proc *p;
1087 {
1088
1089 p->p_stat = SSTOP;
1090 p->p_flag &= ~P_WAITED;
1091 wakeup((caddr_t)p->p_pptr);
1092 }
1093
1094 /*
1095 * Take the action for the specified signal
1096 * from the current set of pending signals.
1097 */
1098 void
1099 postsig(signum)
1100 register int signum;
1101 {
1102 register struct proc *p = curproc;
1103 register struct sigacts *ps = p->p_sigacts;
1104 register sig_t action;
1105 int code, mask, returnmask;
1106
1107 #ifdef DIAGNOSTIC
1108 if (signum == 0)
1109 panic("postsig");
1110 #endif
1111 mask = sigmask(signum);
1112 p->p_siglist &= ~mask;
1113 action = ps->ps_sigact[signum];
1114 #ifdef KTRACE
1115 if (KTRPOINT(p, KTR_PSIG))
1116 ktrpsig(p->p_tracep,
1117 signum, action, ps->ps_flags & SAS_OLDMASK ?
1118 ps->ps_oldmask : p->p_sigmask, 0);
1119 #endif
1120 if (action == SIG_DFL) {
1121 /*
1122 * Default action, where the default is to kill
1123 * the process. (Other cases were ignored above.)
1124 */
1125 sigexit(p, signum);
1126 /* NOTREACHED */
1127 } else {
1128 /*
1129 * If we get here, the signal must be caught.
1130 */
1131 #ifdef DIAGNOSTIC
1132 if (action == SIG_IGN || (p->p_sigmask & mask))
1133 panic("postsig action");
1134 #endif
1135 /*
1136 * Set the new mask value and also defer further
1137 * occurences of this signal.
1138 *
1139 * Special case: user has done a sigpause. Here the
1140 * current mask is not of interest, but rather the
1141 * mask from before the sigpause is what we want
1142 * restored after the signal processing is completed.
1143 */
1144 (void) splhigh();
1145 if (ps->ps_flags & SAS_OLDMASK) {
1146 returnmask = ps->ps_oldmask;
1147 ps->ps_flags &= ~SAS_OLDMASK;
1148 } else
1149 returnmask = p->p_sigmask;
1150 p->p_sigmask |= ps->ps_catchmask[signum] |
1151 (mask & ~ps->ps_signodefer);
1152 if ((ps->ps_sigreset & mask) != 0) {
1153 /*
1154 * See setsigvec() for origin of this code.
1155 */
1156 p->p_sigcatch &= ~mask;
1157 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
1158 p->p_sigignore |= mask;
1159 ps->ps_sigact[signum] = SIG_DFL;
1160 }
1161 (void) spl0();
1162 p->p_stats->p_ru.ru_nsignals++;
1163 if (ps->ps_sig != signum) {
1164 code = 0;
1165 } else {
1166 code = ps->ps_code;
1167 ps->ps_code = 0;
1168 ps->ps_sig = 0;
1169 }
1170 (*p->p_sysent->sv_sendsig)(action, signum, returnmask, code);
1171 }
1172 }
1173
1174 /*
1175 * Kill the current process for stated reason.
1176 */
1177 void
1178 killproc(p, why)
1179 struct proc *p;
1180 char *why;
1181 {
1182 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
1183 p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1184 psignal(p, SIGKILL);
1185 }
1186
1187 /*
1188 * Force the current process to exit with the specified signal, dumping core
1189 * if appropriate. We bypass the normal tests for masked and caught signals,
1190 * allowing unrecoverable failures to terminate the process without changing
1191 * signal state. Mark the accounting record with the signal termination.
1192 * If dumping core, save the signal number for the debugger. Calls exit and
1193 * does not return.
1194 */
1195 void
1196 sigexit(p, signum)
1197 register struct proc *p;
1198 int signum;
1199 {
1200
1201 p->p_acflag |= AXSIG;
1202 if (sigprop[signum] & SA_CORE) {
1203 p->p_sigacts->ps_sig = signum;
1204 /*
1205 * Log signals which would cause core dumps
1206 * (Log as LOG_INFO to appease those who don't want
1207 * these messages.)
1208 * XXX : Todo, as well as euid, write out ruid too
1209 */
1210 if (coredump(p) == 0)
1211 signum |= WCOREFLAG;
1212 log(LOG_INFO, "pid %d (%s), uid %d: exited on signal %d%s\n",
1213 p->p_pid, p->p_comm,
1214 p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1,
1215 signum &~ WCOREFLAG,
1216 signum & WCOREFLAG ? " (core dumped)" : "");
1217 }
1218 exit1(p, W_EXITCODE(0, signum));
1219 /* NOTREACHED */
1220 }
1221
1222 /*
1223 * Dump core, into a file named "progname.core", unless the process was
1224 * setuid/setgid.
1225 */
1226 static int
1227 coredump(p)
1228 register struct proc *p;
1229 {
1230 register struct vnode *vp;
1231 register struct ucred *cred = p->p_cred->pc_ucred;
1232 register struct vmspace *vm = p->p_vmspace;
1233 struct nameidata nd;
1234 struct vattr vattr;
1235 int error, error1;
1236 char name[MAXCOMLEN+6]; /* progname.core */
1237
1238 if (p->p_flag & P_SUGID)
1239 return (EFAULT);
1240 if (ctob(UPAGES + vm->vm_dsize + vm->vm_ssize) >=
1241 p->p_rlimit[RLIMIT_CORE].rlim_cur)
1242 return (EFAULT);
1243 sprintf(name, "%s.core", p->p_comm);
1244 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
1245 if ((error = vn_open(&nd,
1246 O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR)))
1247 return (error);
1248 vp = nd.ni_vp;
1249
1250 /* Don't dump to non-regular files or files with links. */
1251 if (vp->v_type != VREG ||
1252 VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) {
1253 error = EFAULT;
1254 goto out;
1255 }
1256 VATTR_NULL(&vattr);
1257 vattr.va_size = 0;
1258 LEASE_CHECK(vp, p, cred, LEASE_WRITE);
1259 VOP_SETATTR(vp, &vattr, cred, p);
1260 p->p_acflag |= ACORE;
1261 bcopy(p, &p->p_addr->u_kproc.kp_proc, sizeof(struct proc));
1262 fill_eproc(p, &p->p_addr->u_kproc.kp_eproc);
1263 error = cpu_coredump(p, vp, cred);
1264 if (error == 0)
1265 error = vn_rdwr(UIO_WRITE, vp, vm->vm_daddr,
1266 (int)ctob(vm->vm_dsize), (off_t)ctob(UPAGES), UIO_USERSPACE,
1267 IO_NODELOCKED|IO_UNIT, cred, (int *) NULL, p);
1268 if (error == 0)
1269 error = vn_rdwr(UIO_WRITE, vp,
1270 (caddr_t) trunc_page(USRSTACK - ctob(vm->vm_ssize)),
1271 round_page(ctob(vm->vm_ssize)),
1272 (off_t)ctob(UPAGES) + ctob(vm->vm_dsize), UIO_USERSPACE,
1273 IO_NODELOCKED|IO_UNIT, cred, (int *) NULL, p);
1274 out:
1275 VOP_UNLOCK(vp);
1276 error1 = vn_close(vp, FWRITE, cred, p);
1277 if (error == 0)
1278 error = error1;
1279 return (error);
1280 }
1281
1282 /*
1283 * Nonexistent system call-- signal process (may want to handle it).
1284 * Flag error in case process won't see signal immediately (blocked or ignored).
1285 */
1286 #ifndef _SYS_SYSPROTO_H_
1287 struct nosys_args {
1288 int dummy;
1289 };
1290 #endif
1291 /* ARGSUSED */
1292 int
1293 nosys(p, args, retval)
1294 struct proc *p;
1295 struct nosys_args *args;
1296 int *retval;
1297 {
1298
1299 psignal(p, SIGSYS);
1300 return (EINVAL);
1301 }
Cache object: a9b04cd1553adca1a3087cc490449031
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