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1.1 root 1: /*
2: * Copyright (c) 1982, 1986, 1989, 1991 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. All advertising materials mentioning features or use of this software
14: * must display the following acknowledgement:
15: * This product includes software developed by the University of
16: * California, Berkeley and its contributors.
17: * 4. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: *
33: * @(#)kern_sig.c 7.35 (Berkeley) 6/28/91
34: */
35:
36: #define SIGPROP /* include signal properties table */
37: #include "param.h"
38: #include "signalvar.h"
39: #include "resourcevar.h"
40: #include "namei.h"
41: #include "vnode.h"
42: #include "proc.h"
43: #include "systm.h"
44: #include "timeb.h"
45: #include "times.h"
46: #include "buf.h"
47: #include "acct.h"
48: #include "file.h"
49: #include "kernel.h"
50: #include "wait.h"
51: #include "ktrace.h"
52:
53: #include "machine/cpu.h"
54:
55: #include "vm/vm.h"
56: #include "kinfo_proc.h"
57: #include "user.h" /* for coredump */
58:
59: /*
60: * Can process p, with pcred pc, send the signal signo to process q?
61: */
62: #define CANSIGNAL(p, pc, q, signo) \
63: ((pc)->pc_ucred->cr_uid == 0 || \
64: (pc)->p_ruid == (q)->p_cred->p_ruid || \
65: (pc)->pc_ucred->cr_uid == (q)->p_cred->p_ruid || \
66: (pc)->p_ruid == (q)->p_ucred->cr_uid || \
67: (pc)->pc_ucred->cr_uid == (q)->p_ucred->cr_uid || \
68: ((signo) == SIGCONT && (q)->p_session == (p)->p_session))
69:
70: /* ARGSUSED */
71: sigaction(p, uap, retval)
72: struct proc *p;
73: register struct args {
74: int signo;
75: struct sigaction *nsa;
76: struct sigaction *osa;
77: } *uap;
78: int *retval;
79: {
80: struct sigaction vec;
81: register struct sigaction *sa;
82: register struct sigacts *ps = p->p_sigacts;
83: register int sig;
84: int bit, error;
85:
86: sig = uap->signo;
87: if (sig <= 0 || sig >= NSIG || sig == SIGKILL || sig == SIGSTOP)
88: return (EINVAL);
89: sa = &vec;
90: if (uap->osa) {
91: sa->sa_handler = ps->ps_sigact[sig];
92: sa->sa_mask = ps->ps_catchmask[sig];
93: bit = sigmask(sig);
94: sa->sa_flags = 0;
95: if ((ps->ps_sigonstack & bit) != 0)
96: sa->sa_flags |= SA_ONSTACK;
97: if ((ps->ps_sigintr & bit) == 0)
98: sa->sa_flags |= SA_RESTART;
99: if (p->p_flag & SNOCLDSTOP)
100: sa->sa_flags |= SA_NOCLDSTOP;
101: if (error = copyout((caddr_t)sa, (caddr_t)uap->osa,
102: sizeof (vec)))
103: return (error);
104: }
105: if (uap->nsa) {
106: if (error = copyin((caddr_t)uap->nsa, (caddr_t)sa,
107: sizeof (vec)))
108: return (error);
109: setsigvec(p, sig, sa);
110: }
111: return (0);
112: }
113:
114: setsigvec(p, sig, sa)
115: register struct proc *p;
116: int sig;
117: register struct sigaction *sa;
118: {
119: register struct sigacts *ps = p->p_sigacts;
120: register int bit;
121:
122: bit = sigmask(sig);
123: /*
124: * Change setting atomically.
125: */
126: (void) splhigh();
127: ps->ps_sigact[sig] = sa->sa_handler;
128: ps->ps_catchmask[sig] = sa->sa_mask &~ sigcantmask;
129: if ((sa->sa_flags & SA_RESTART) == 0)
130: ps->ps_sigintr |= bit;
131: else
132: ps->ps_sigintr &= ~bit;
133: if (sa->sa_flags & SA_ONSTACK)
134: ps->ps_sigonstack |= bit;
135: else
136: ps->ps_sigonstack &= ~bit;
137: if (sig == SIGCHLD) {
138: if (sa->sa_flags & SA_NOCLDSTOP)
139: p->p_flag |= SNOCLDSTOP;
140: else
141: p->p_flag &= ~SNOCLDSTOP;
142: }
143: /*
144: * Set bit in p_sigignore for signals that are set to SIG_IGN,
145: * and for signals set to SIG_DFL where the default is to ignore.
146: * However, don't put SIGCONT in p_sigignore,
147: * as we have to restart the process.
148: */
149: if (sa->sa_handler == SIG_IGN ||
150: (sigprop[sig] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
151: p->p_sig &= ~bit; /* never to be seen again */
152: if (sig != SIGCONT)
153: p->p_sigignore |= bit; /* easier in psignal */
154: p->p_sigcatch &= ~bit;
155: } else {
156: p->p_sigignore &= ~bit;
157: if (sa->sa_handler == SIG_DFL)
158: p->p_sigcatch &= ~bit;
159: else
160: p->p_sigcatch |= bit;
161: }
162: (void) spl0();
163: }
164:
165: /*
166: * Initialize signal state for process 0;
167: * set to ignore signals that are ignored by default.
168: */
169: void
170: siginit(p)
171: struct proc *p;
172: {
173: register int i;
174:
175: for (i = 0; i < NSIG; i++)
176: if (sigprop[i] & SA_IGNORE && i != SIGCONT)
177: p->p_sigignore |= sigmask(i);
178: }
179:
180: /*
181: * Reset signals for an exec of the specified process.
182: */
183: void
184: execsigs(p)
185: register struct proc *p;
186: {
187: register struct sigacts *ps = p->p_sigacts;
188: register int nc, mask;
189:
190: /*
191: * Reset caught signals. Held signals remain held
192: * through p_sigmask (unless they were caught,
193: * and are now ignored by default).
194: */
195: while (p->p_sigcatch) {
196: nc = ffs((long)p->p_sigcatch);
197: mask = sigmask(nc);
198: p->p_sigcatch &= ~mask;
199: if (sigprop[nc] & SA_IGNORE) {
200: if (nc != SIGCONT)
201: p->p_sigignore |= mask;
202: p->p_sig &= ~mask;
203: }
204: ps->ps_sigact[nc] = SIG_DFL;
205: }
206: /*
207: * Reset stack state to the user stack.
208: * Clear set of signals caught on the signal stack.
209: */
210: ps->ps_onstack = 0;
211: ps->ps_sigsp = 0;
212: ps->ps_sigonstack = 0;
213: }
214:
215: /*
216: * Manipulate signal mask.
217: * Note that we receive new mask, not pointer,
218: * and return old mask as return value;
219: * the library stub does the rest.
220: */
221: sigprocmask(p, uap, retval)
222: register struct proc *p;
223: struct args {
224: int how;
225: sigset_t mask;
226: } *uap;
227: int *retval;
228: {
229: int error = 0;
230:
231: *retval = p->p_sigmask;
232: (void) splhigh();
233:
234: switch (uap->how) {
235: case SIG_BLOCK:
236: p->p_sigmask |= uap->mask &~ sigcantmask;
237: break;
238:
239: case SIG_UNBLOCK:
240: p->p_sigmask &= ~uap->mask;
241: break;
242:
243: case SIG_SETMASK:
244: p->p_sigmask = uap->mask &~ sigcantmask;
245: break;
246:
247: default:
248: error = EINVAL;
249: break;
250: }
251: (void) spl0();
252: return (error);
253: }
254:
255: /* ARGSUSED */
256: sigpending(p, uap, retval)
257: struct proc *p;
258: void *uap;
259: int *retval;
260: {
261:
262: *retval = p->p_sig;
263: return (0);
264: }
265:
266: #ifdef COMPAT_43
267: /*
268: * Generalized interface signal handler, 4.3-compatible.
269: */
270: /* ARGSUSED */
271: osigvec(p, uap, retval)
272: struct proc *p;
273: register struct args {
274: int signo;
275: struct sigvec *nsv;
276: struct sigvec *osv;
277: } *uap;
278: int *retval;
279: {
280: struct sigvec vec;
281: register struct sigacts *ps = p->p_sigacts;
282: register struct sigvec *sv;
283: register int sig;
284: int bit, error;
285:
286: sig = uap->signo;
287: if (sig <= 0 || sig >= NSIG || sig == SIGKILL || sig == SIGSTOP)
288: return (EINVAL);
289: sv = &vec;
290: if (uap->osv) {
291: *(sig_t *)&sv->sv_handler = ps->ps_sigact[sig];
292: sv->sv_mask = ps->ps_catchmask[sig];
293: bit = sigmask(sig);
294: sv->sv_flags = 0;
295: if ((ps->ps_sigonstack & bit) != 0)
296: sv->sv_flags |= SV_ONSTACK;
297: if ((ps->ps_sigintr & bit) != 0)
298: sv->sv_flags |= SV_INTERRUPT;
299: if (p->p_flag & SNOCLDSTOP)
300: sv->sv_flags |= SA_NOCLDSTOP;
301: if (error = copyout((caddr_t)sv, (caddr_t)uap->osv,
302: sizeof (vec)))
303: return (error);
304: }
305: if (uap->nsv) {
306: if (error = copyin((caddr_t)uap->nsv, (caddr_t)sv,
307: sizeof (vec)))
308: return (error);
309: sv->sv_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
310: setsigvec(p, sig, (struct sigaction *)sv);
311: }
312: return (0);
313: }
314:
315: osigblock(p, uap, retval)
316: register struct proc *p;
317: struct args {
318: int mask;
319: } *uap;
320: int *retval;
321: {
322:
323: (void) splhigh();
324: *retval = p->p_sigmask;
325: p->p_sigmask |= uap->mask &~ sigcantmask;
326: (void) spl0();
327: return (0);
328: }
329:
330: osigsetmask(p, uap, retval)
331: struct proc *p;
332: struct args {
333: int mask;
334: } *uap;
335: int *retval;
336: {
337:
338: (void) splhigh();
339: *retval = p->p_sigmask;
340: p->p_sigmask = uap->mask &~ sigcantmask;
341: (void) spl0();
342: return (0);
343: }
344: #endif
345:
346: /*
347: * Suspend process until signal, providing mask to be set
348: * in the meantime. Note nonstandard calling convention:
349: * libc stub passes mask, not pointer, to save a copyin.
350: */
351: /* ARGSUSED */
352: sigsuspend(p, uap, retval)
353: register struct proc *p;
354: struct args {
355: sigset_t mask;
356: } *uap;
357: int *retval;
358: {
359: register struct sigacts *ps = p->p_sigacts;
360:
361: /*
362: * When returning from sigpause, we want
363: * the old mask to be restored after the
364: * signal handler has finished. Thus, we
365: * save it here and mark the proc structure
366: * to indicate this (should be in sigacts).
367: */
368: ps->ps_oldmask = p->p_sigmask;
369: ps->ps_flags |= SA_OLDMASK;
370: p->p_sigmask = uap->mask &~ sigcantmask;
371: (void) tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0);
372: /* always return EINTR rather than ERESTART... */
373: return (EINTR);
374: }
375:
376: /* ARGSUSED */
377: sigstack(p, uap, retval)
378: struct proc *p;
379: register struct args {
380: struct sigstack *nss;
381: struct sigstack *oss;
382: } *uap;
383: int *retval;
384: {
385: struct sigstack ss;
386: int error = 0;
387:
388: if (uap->oss && (error = copyout((caddr_t)&p->p_sigacts->ps_sigstack,
389: (caddr_t)uap->oss, sizeof (struct sigstack))))
390: return (error);
391: if (uap->nss && (error = copyin((caddr_t)uap->nss, (caddr_t)&ss,
392: sizeof (ss))) == 0)
393: p->p_sigacts->ps_sigstack = ss;
394: return (error);
395: }
396:
397: /* ARGSUSED */
398: kill(cp, uap, retval)
399: register struct proc *cp;
400: register struct args {
401: int pid;
402: int signo;
403: } *uap;
404: int *retval;
405: {
406: register struct proc *p;
407: register struct pcred *pc = cp->p_cred;
408:
409: if ((unsigned) uap->signo >= NSIG)
410: return (EINVAL);
411: if (uap->pid > 0) {
412: /* kill single process */
413: p = pfind(uap->pid);
414: if (p == 0)
415: return (ESRCH);
416: if (!CANSIGNAL(cp, pc, p, uap->signo))
417: return (EPERM);
418: if (uap->signo)
419: psignal(p, uap->signo);
420: return (0);
421: }
422: switch (uap->pid) {
423: case -1: /* broadcast signal */
424: return (killpg1(cp, uap->signo, 0, 1));
425: case 0: /* signal own process group */
426: return (killpg1(cp, uap->signo, 0, 0));
427: default: /* negative explicit process group */
428: return (killpg1(cp, uap->signo, -uap->pid, 0));
429: }
430: /* NOTREACHED */
431: }
432:
433: #ifdef COMPAT_43
434: /* ARGSUSED */
435: okillpg(p, uap, retval)
436: struct proc *p;
437: register struct args {
438: int pgid;
439: int signo;
440: } *uap;
441: int *retval;
442: {
443:
444: if ((unsigned) uap->signo >= NSIG)
445: return (EINVAL);
446: return (killpg1(p, uap->signo, uap->pgid, 0));
447: }
448: #endif
449:
450: /*
451: * Common code for kill process group/broadcast kill.
452: * cp is calling process.
453: */
454: killpg1(cp, signo, pgid, all)
455: register struct proc *cp;
456: int signo, pgid, all;
457: {
458: register struct proc *p;
459: register struct pcred *pc = cp->p_cred;
460: struct pgrp *pgrp;
461: int nfound = 0;
462:
463: if (all)
464: /*
465: * broadcast
466: */
467: for (p = allproc; p != NULL; p = p->p_nxt) {
468: if (p->p_pid <= 1 || p->p_flag&SSYS ||
469: p == cp || !CANSIGNAL(cp, pc, p, signo))
470: continue;
471: nfound++;
472: if (signo)
473: psignal(p, signo);
474: }
475: else {
476: if (pgid == 0)
477: /*
478: * zero pgid means send to my process group.
479: */
480: pgrp = cp->p_pgrp;
481: else {
482: pgrp = pgfind(pgid);
483: if (pgrp == NULL)
484: return (ESRCH);
485: }
486: for (p = pgrp->pg_mem; p != NULL; p = p->p_pgrpnxt) {
487: if (p->p_pid <= 1 || p->p_flag&SSYS ||
488: p->p_stat == SZOMB || !CANSIGNAL(cp, pc, p, signo))
489: continue;
490: nfound++;
491: if (signo)
492: psignal(p, signo);
493: }
494: }
495: return (nfound ? 0 : ESRCH);
496: }
497:
498: /*
499: * Send the specified signal to
500: * all processes with 'pgid' as
501: * process group.
502: */
503: void
504: gsignal(pgid, sig)
505: int pgid, sig;
506: {
507: struct pgrp *pgrp;
508:
509: if (pgid && (pgrp = pgfind(pgid)))
510: pgsignal(pgrp, sig, 0);
511: }
512:
513: /*
514: * Send sig to every member of a process group.
515: * If checktty is 1, limit to members which have a controlling
516: * terminal.
517: */
518: void
519: pgsignal(pgrp, sig, checkctty)
520: struct pgrp *pgrp;
521: int sig, checkctty;
522: {
523: register struct proc *p;
524:
525: if (pgrp)
526: for (p = pgrp->pg_mem; p != NULL; p = p->p_pgrpnxt)
527: if (checkctty == 0 || p->p_flag&SCTTY)
528: psignal(p, sig);
529: }
530:
531: /*
532: * Send a signal caused by a trap to the current process.
533: * If it will be caught immediately, deliver it with correct code.
534: * Otherwise, post it normally.
535: */
536: void
537: trapsignal(p, sig, code)
538: struct proc *p;
539: register int sig;
540: unsigned code;
541: {
542: register struct sigacts *ps = p->p_sigacts;
543: int mask;
544:
545: mask = sigmask(sig);
546: if ((p->p_flag & STRC) == 0 && (p->p_sigcatch & mask) != 0 &&
547: (p->p_sigmask & mask) == 0) {
548: p->p_stats->p_ru.ru_nsignals++;
549: #ifdef KTRACE
550: if (KTRPOINT(p, KTR_PSIG))
551: ktrpsig(p->p_tracep, sig, ps->ps_sigact[sig],
552: p->p_sigmask, code);
553: #endif
554: sendsig(ps->ps_sigact[sig], sig, p->p_sigmask, code);
555: p->p_sigmask |= ps->ps_catchmask[sig] | mask;
556: } else {
557: ps->ps_code = code; /* XXX for core dump/debugger */
558: psignal(p, sig);
559: }
560: }
561:
562: /*
563: * Send the specified signal to the specified process.
564: * If the signal has an action, the action is usually performed
565: * by the target process rather than the caller; we simply add
566: * the signal to the set of pending signals for the process.
567: * Exceptions:
568: * o When a stop signal is sent to a sleeping process that takes the default
569: * action, the process is stopped without awakening it.
570: * o SIGCONT restarts stopped processes (or puts them back to sleep)
571: * regardless of the signal action (eg, blocked or ignored).
572: * Other ignored signals are discarded immediately.
573: */
574: void
575: psignal(p, sig)
576: register struct proc *p;
577: register int sig;
578: {
579: register int s, prop;
580: register sig_t action;
581: int mask;
582:
583: if ((unsigned)sig >= NSIG || sig == 0)
584: panic("psignal sig");
585: mask = sigmask(sig);
586: prop = sigprop[sig];
587:
588: /*
589: * If proc is traced, always give parent a chance.
590: */
591: if (p->p_flag & STRC)
592: action = SIG_DFL;
593: else {
594: /*
595: * If the signal is being ignored,
596: * then we forget about it immediately.
597: * (Note: we don't set SIGCONT in p_sigignore,
598: * and if it is set to SIG_IGN,
599: * action will be SIG_DFL here.)
600: */
601: if (p->p_sigignore & mask)
602: return;
603: if (p->p_sigmask & mask)
604: action = SIG_HOLD;
605: else if (p->p_sigcatch & mask)
606: action = SIG_CATCH;
607: else
608: action = SIG_DFL;
609: }
610:
611: if (p->p_nice > NZERO && (sig == SIGKILL ||
612: sig == SIGTERM && (p->p_flag&STRC || action != SIG_DFL)))
613: p->p_nice = NZERO;
614:
615: if (prop & SA_CONT)
616: p->p_sig &= ~stopsigmask;
617:
618: if (prop & SA_STOP) {
619: /*
620: * If sending a tty stop signal to a member of an orphaned
621: * process group, discard the signal here if the action
622: * is default; don't stop the process below if sleeping,
623: * and don't clear any pending SIGCONT.
624: */
625: if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
626: action == SIG_DFL)
627: return;
628: p->p_sig &= ~contsigmask;
629: }
630: p->p_sig |= mask;
631:
632: /*
633: * Defer further processing for signals which are held,
634: * except that stopped processes must be continued by SIGCONT.
635: */
636: if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
637: return;
638: s = splhigh();
639: switch (p->p_stat) {
640:
641: case SSLEEP:
642: /*
643: * If process is sleeping uninterruptibly
644: * we can't interrupt the sleep... the signal will
645: * be noticed when the process returns through
646: * trap() or syscall().
647: */
648: if ((p->p_flag & SSINTR) == 0)
649: goto out;
650: /*
651: * Process is sleeping and traced... make it runnable
652: * so it can discover the signal in issig() and stop
653: * for the parent.
654: */
655: if (p->p_flag&STRC)
656: goto run;
657: /*
658: * When a sleeping process receives a stop
659: * signal, process immediately if possible.
660: * All other (caught or default) signals
661: * cause the process to run.
662: */
663: if (prop & SA_STOP) {
664: if (action != SIG_DFL)
665: goto runfast;
666: /*
667: * If a child holding parent blocked,
668: * stopping could cause deadlock.
669: */
670: if (p->p_flag&SPPWAIT)
671: goto out;
672: p->p_sig &= ~mask;
673: p->p_xstat = sig;
674: if ((p->p_pptr->p_flag & SNOCLDSTOP) == 0)
675: psignal(p->p_pptr, SIGCHLD);
676: stop(p);
677: goto out;
678: } else
679: goto runfast;
680: /*NOTREACHED*/
681:
682: case SSTOP:
683: /*
684: * If traced process is already stopped,
685: * then no further action is necessary.
686: */
687: if (p->p_flag&STRC)
688: goto out;
689:
690: /*
691: * Kill signal always sets processes running.
692: */
693: if (sig == SIGKILL)
694: goto runfast;
695:
696: if (prop & SA_CONT) {
697: /*
698: * If SIGCONT is default (or ignored), we continue
699: * the process but don't leave the signal in p_sig,
700: * as it has no further action. If SIGCONT is held,
701: * continue the process and leave the signal in p_sig.
702: * If the process catches SIGCONT, let it handle
703: * the signal itself. If it isn't waiting on
704: * an event, then it goes back to run state.
705: * Otherwise, process goes back to sleep state.
706: */
707: if (action == SIG_DFL)
708: p->p_sig &= ~mask;
709: if (action == SIG_CATCH)
710: goto runfast;
711: if (p->p_wchan == 0)
712: goto run;
713: p->p_stat = SSLEEP;
714: goto out;
715: }
716:
717: if (prop & SA_STOP) {
718: /*
719: * Already stopped, don't need to stop again.
720: * (If we did the shell could get confused.)
721: */
722: p->p_sig &= ~mask; /* take it away */
723: goto out;
724: }
725:
726: /*
727: * If process is sleeping interruptibly, then
728: * simulate a wakeup so that when it is continued,
729: * it will be made runnable and can look at the signal.
730: * But don't setrun the process, leave it stopped.
731: */
732: if (p->p_wchan && p->p_flag & SSINTR)
733: unsleep(p);
734: goto out;
735:
736: default:
737: /*
738: * SRUN, SIDL, SZOMB do nothing with the signal,
739: * other than kicking ourselves if we are running.
740: * It will either never be noticed, or noticed very soon.
741: */
742: if (p == curproc)
743: signotify(p);
744: goto out;
745: }
746: /*NOTREACHED*/
747:
748: runfast:
749: /*
750: * Raise priority to at least PUSER.
751: */
752: if (p->p_pri > PUSER)
753: p->p_pri = PUSER;
754: run:
755: setrun(p);
756: out:
757: splx(s);
758: }
759:
760: /*
761: * If the current process has a signal to process (should be caught
762: * or cause termination, should interrupt current syscall),
763: * return the signal number. Stop signals with default action
764: * are processed immediately, then cleared; they aren't returned.
765: * This is checked after each entry to the system for a syscall
766: * or trap (though this can usually be done without actually calling
767: * issig by checking the pending signal masks in the CURSIG macro.)
768: * The normal call sequence is
769: *
770: * while (sig = CURSIG(curproc))
771: * psig(sig);
772: */
773: issig(p)
774: register struct proc *p;
775: {
776: register int sig, mask, prop;
777:
778: for (;;) {
779: mask = p->p_sig &~ p->p_sigmask;
780: if (p->p_flag&SPPWAIT)
781: mask &= ~stopsigmask;
782: if (mask == 0) /* no signal to send */
783: return (0);
784: sig = ffs((long)mask);
785: mask = sigmask(sig);
786: prop = sigprop[sig];
787: /*
788: * We should see pending but ignored signals
789: * only if STRC was on when they were posted.
790: */
791: if (mask & p->p_sigignore && (p->p_flag&STRC) == 0) {
792: p->p_sig &= ~mask;
793: continue;
794: }
795: if (p->p_flag&STRC && (p->p_flag&SPPWAIT) == 0) {
796: /*
797: * If traced, always stop, and stay
798: * stopped until released by the parent.
799: */
800: p->p_xstat = sig;
801: psignal(p->p_pptr, SIGCHLD);
802: do {
803: stop(p);
804: swtch();
805: } while (!procxmt(p) && p->p_flag&STRC);
806:
807: /*
808: * If the traced bit got turned off,
809: * go back up to the top to rescan signals.
810: * This ensures that p_sig* and ps_sigact
811: * are consistent.
812: */
813: if ((p->p_flag&STRC) == 0)
814: continue;
815:
816: /*
817: * If parent wants us to take the signal,
818: * then it will leave it in p->p_xstat;
819: * otherwise we just look for signals again.
820: */
821: p->p_sig &= ~mask; /* clear the old signal */
822: sig = p->p_xstat;
823: if (sig == 0)
824: continue;
825:
826: /*
827: * Put the new signal into p_sig.
828: * If signal is being masked,
829: * look for other signals.
830: */
831: mask = sigmask(sig);
832: p->p_sig |= mask;
833: if (p->p_sigmask & mask)
834: continue;
835: }
836:
837: /*
838: * Decide whether the signal should be returned.
839: * Return the signal's number, or fall through
840: * to clear it from the pending mask.
841: */
842: switch ((int)p->p_sigacts->ps_sigact[sig]) {
843:
844: case SIG_DFL:
845: /*
846: * Don't take default actions on system processes.
847: */
848: if (p->p_pid <= 1)
849: break; /* == ignore */
850: /*
851: * If there is a pending stop signal to process
852: * with default action, stop here,
853: * then clear the signal. However,
854: * if process is member of an orphaned
855: * process group, ignore tty stop signals.
856: */
857: if (prop & SA_STOP) {
858: if (p->p_flag&STRC ||
859: (p->p_pgrp->pg_jobc == 0 &&
860: prop & SA_TTYSTOP))
861: break; /* == ignore */
862: p->p_xstat = sig;
863: stop(p);
864: if ((p->p_pptr->p_flag & SNOCLDSTOP) == 0)
865: psignal(p->p_pptr, SIGCHLD);
866: swtch();
867: break;
868: } else if (prop & SA_IGNORE) {
869: /*
870: * Except for SIGCONT, shouldn't get here.
871: * Default action is to ignore; drop it.
872: */
873: break; /* == ignore */
874: } else
875: return (sig);
876: /*NOTREACHED*/
877:
878: case SIG_IGN:
879: /*
880: * Masking above should prevent us ever trying
881: * to take action on an ignored signal other
882: * than SIGCONT, unless process is traced.
883: */
884: if ((prop & SA_CONT) == 0 && (p->p_flag&STRC) == 0)
885: printf("issig\n");
886: break; /* == ignore */
887:
888: default:
889: /*
890: * This signal has an action, let
891: * psig process it.
892: */
893: return (sig);
894: }
895: p->p_sig &= ~mask; /* take the signal! */
896: }
897: /* NOTREACHED */
898: }
899:
900: /*
901: * Put the argument process into the stopped
902: * state and notify the parent via wakeup.
903: * Signals are handled elsewhere.
904: * The process must not be on the run queue.
905: */
906: stop(p)
907: register struct proc *p;
908: {
909:
910: p->p_stat = SSTOP;
911: p->p_flag &= ~SWTED;
912: wakeup((caddr_t)p->p_pptr);
913: }
914:
915: /*
916: * Take the action for the specified signal
917: * from the current set of pending signals.
918: */
919: void
920: psig(sig)
921: register int sig;
922: {
923: register struct proc *p = curproc;
924: register struct sigacts *ps = p->p_sigacts;
925: register sig_t action;
926: int mask, returnmask;
927:
928: #ifdef DIAGNOSTIC
929: if (sig == 0)
930: panic("psig");
931: #endif
932: mask = sigmask(sig);
933: p->p_sig &= ~mask;
934: action = ps->ps_sigact[sig];
935: #ifdef KTRACE
936: if (KTRPOINT(p, KTR_PSIG))
937: ktrpsig(p->p_tracep, sig, action, ps->ps_flags & SA_OLDMASK ?
938: ps->ps_oldmask : p->p_sigmask, 0);
939: #endif
940: if (action == SIG_DFL) {
941: /*
942: * Default action, where the default is to kill
943: * the process. (Other cases were ignored above.)
944: */
945: sigexit(p, sig);
946: /* NOTREACHED */
947: } else {
948: /*
949: * If we get here, the signal must be caught.
950: */
951: #ifdef DIAGNOSTIC
952: if (action == SIG_IGN || (p->p_sigmask & mask))
953: panic("psig action");
954: #endif
955: /*
956: * Set the new mask value and also defer further
957: * occurences of this signal.
958: *
959: * Special case: user has done a sigpause. Here the
960: * current mask is not of interest, but rather the
961: * mask from before the sigpause is what we want
962: * restored after the signal processing is completed.
963: */
964: (void) splhigh();
965: if (ps->ps_flags & SA_OLDMASK) {
966: returnmask = ps->ps_oldmask;
967: ps->ps_flags &= ~SA_OLDMASK;
968: } else
969: returnmask = p->p_sigmask;
970: p->p_sigmask |= ps->ps_catchmask[sig] | mask;
971: (void) spl0();
972: p->p_stats->p_ru.ru_nsignals++;
973: sendsig(action, sig, returnmask, 0);
974: }
975: }
976:
977: /*
978: * Force the current process to exit with the specified
979: * signal, dumping core if appropriate. We bypass the normal
980: * tests for masked and caught signals, allowing unrecoverable
981: * failures to terminate the process without changing signal state.
982: * Mark the accounting record with the signal termination.
983: * If dumping core, save the signal number for the debugger.
984: * Calls exit and does not return.
985: */
986: sigexit(p, sig)
987: register struct proc *p;
988: int sig;
989: {
990:
991: p->p_acflag |= AXSIG;
992: if (sigprop[sig] & SA_CORE) {
993: p->p_sigacts->ps_sig = sig;
994: if (coredump(p) == 0)
995: sig |= WCOREFLAG;
996: }
997: exit(p, W_EXITCODE(0, sig));
998: /* NOTREACHED */
999: }
1000:
1001: /*
1002: * Create a core dump.
1003: * The file name is "core.progname".
1004: * Core dumps are not created if the process is setuid.
1005: */
1006: coredump(p)
1007: register struct proc *p;
1008: {
1009: register struct vnode *vp;
1010: register struct pcred *pcred = p->p_cred;
1011: register struct ucred *cred = pcred->pc_ucred;
1012: register struct vmspace *vm = p->p_vmspace;
1013: struct vattr vattr;
1014: int error, error1;
1015: struct nameidata nd;
1016: char name[MAXCOMLEN+6]; /* core.progname */
1017:
1018: if (pcred->p_svuid != pcred->p_ruid ||
1019: pcred->p_svgid != pcred->p_rgid)
1020: return (EFAULT);
1021: if (ctob(UPAGES + vm->vm_dsize + vm->vm_ssize) >=
1022: p->p_rlimit[RLIMIT_CORE].rlim_cur)
1023: return (EFAULT);
1024: sprintf(name, "core.%s", p->p_comm);
1025: nd.ni_dirp = name;
1026: nd.ni_segflg = UIO_SYSSPACE;
1027: if (error = vn_open(&nd, p, O_CREAT|FWRITE, 0644))
1028: return (error);
1029: vp = nd.ni_vp;
1030: if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred, p) ||
1031: vattr.va_nlink != 1) {
1032: error = EFAULT;
1033: goto out;
1034: }
1035: VATTR_NULL(&vattr);
1036: vattr.va_size = 0;
1037: VOP_SETATTR(vp, &vattr, cred, p);
1038: p->p_acflag |= ACORE;
1039: bcopy(p, &p->p_addr->u_kproc.kp_proc, sizeof(struct proc));
1040: fill_eproc(p, &p->p_addr->u_kproc.kp_eproc);
1041: #ifdef HPUXCOMPAT
1042: /*
1043: * BLETCH! If we loaded from an HPUX format binary file
1044: * we have to dump an HPUX style user struct so that the
1045: * HPUX debuggers can grok it.
1046: */
1047: if (p->p_addr->u_pcb.pcb_flags & PCB_HPUXBIN)
1048: error = hpuxdumpu(vp, cred);
1049: else
1050: #endif
1051: error = vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES),
1052: (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *) NULL,
1053: p);
1054: if (error == 0)
1055: error = vn_rdwr(UIO_WRITE, vp, vm->vm_daddr,
1056: (int)ctob(vm->vm_dsize), (off_t)ctob(UPAGES), UIO_USERSPACE,
1057: IO_NODELOCKED|IO_UNIT, cred, (int *) NULL, p);
1058: if (error == 0)
1059: error = vn_rdwr(UIO_WRITE, vp,
1060: (caddr_t) trunc_page(USRSTACK - ctob(vm->vm_ssize)),
1061: round_page(ctob(vm->vm_ssize)),
1062: (off_t)ctob(UPAGES) + ctob(vm->vm_dsize), UIO_USERSPACE,
1063: IO_NODELOCKED|IO_UNIT, cred, (int *) NULL, p);
1064: out:
1065: VOP_UNLOCK(vp);
1066: error1 = vn_close(vp, FWRITE, cred, p);
1067: if (error == 0)
1068: error = error1;
1069: return (error);
1070: }
1071:
1072: /*
1073: * Nonexistent system call-- signal process (may want to handle it).
1074: * Flag error in case process won't see signal immediately (blocked or ignored).
1075: */
1076: /* ARGSUSED */
1077: nosys(p, args, retval)
1078: struct proc *p;
1079: void *args;
1080: int *retval;
1081: {
1082:
1083: psignal(p, SIGSYS);
1084: return (EINVAL);
1085: }
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