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 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD: releng/11.2/sys/kern/kern_sig.c 331922 2018-04-03 09:40:52Z kib $");
39
40 #include "opt_compat.h"
41 #include "opt_gzio.h"
42 #include "opt_ktrace.h"
43
44 #include <sys/param.h>
45 #include <sys/ctype.h>
46 #include <sys/systm.h>
47 #include <sys/signalvar.h>
48 #include <sys/vnode.h>
49 #include <sys/acct.h>
50 #include <sys/bus.h>
51 #include <sys/capsicum.h>
52 #include <sys/condvar.h>
53 #include <sys/event.h>
54 #include <sys/fcntl.h>
55 #include <sys/imgact.h>
56 #include <sys/kernel.h>
57 #include <sys/ktr.h>
58 #include <sys/ktrace.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mutex.h>
62 #include <sys/refcount.h>
63 #include <sys/namei.h>
64 #include <sys/proc.h>
65 #include <sys/procdesc.h>
66 #include <sys/posix4.h>
67 #include <sys/pioctl.h>
68 #include <sys/racct.h>
69 #include <sys/resourcevar.h>
70 #include <sys/sdt.h>
71 #include <sys/sbuf.h>
72 #include <sys/sleepqueue.h>
73 #include <sys/smp.h>
74 #include <sys/stat.h>
75 #include <sys/sx.h>
76 #include <sys/syscallsubr.h>
77 #include <sys/sysctl.h>
78 #include <sys/sysent.h>
79 #include <sys/syslog.h>
80 #include <sys/sysproto.h>
81 #include <sys/timers.h>
82 #include <sys/unistd.h>
83 #include <sys/wait.h>
84 #include <vm/vm.h>
85 #include <vm/vm_extern.h>
86 #include <vm/uma.h>
87
88 #include <sys/jail.h>
89
90 #include <machine/cpu.h>
91
92 #include <security/audit/audit.h>
93
94 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
95
96 SDT_PROVIDER_DECLARE(proc);
97 SDT_PROBE_DEFINE3(proc, , , signal__send,
98 "struct thread *", "struct proc *", "int");
99 SDT_PROBE_DEFINE2(proc, , , signal__clear,
100 "int", "ksiginfo_t *");
101 SDT_PROBE_DEFINE3(proc, , , signal__discard,
102 "struct thread *", "struct proc *", "int");
103
104 static int coredump(struct thread *);
105 static int killpg1(struct thread *td, int sig, int pgid, int all,
106 ksiginfo_t *ksi);
107 static int issignal(struct thread *td);
108 static int sigprop(int sig);
109 static void tdsigwakeup(struct thread *, int, sig_t, int);
110 static int sig_suspend_threads(struct thread *, struct proc *, int);
111 static int filt_sigattach(struct knote *kn);
112 static void filt_sigdetach(struct knote *kn);
113 static int filt_signal(struct knote *kn, long hint);
114 static struct thread *sigtd(struct proc *p, int sig, int prop);
115 static void sigqueue_start(void);
116
117 static uma_zone_t ksiginfo_zone = NULL;
118 struct filterops sig_filtops = {
119 .f_isfd = 0,
120 .f_attach = filt_sigattach,
121 .f_detach = filt_sigdetach,
122 .f_event = filt_signal,
123 };
124
125 static int kern_logsigexit = 1;
126 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
127 &kern_logsigexit, 0,
128 "Log processes quitting on abnormal signals to syslog(3)");
129
130 static int kern_forcesigexit = 1;
131 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
132 &kern_forcesigexit, 0, "Force trap signal to be handled");
133
134 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0,
135 "POSIX real time signal");
136
137 static int max_pending_per_proc = 128;
138 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
139 &max_pending_per_proc, 0, "Max pending signals per proc");
140
141 static int preallocate_siginfo = 1024;
142 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
143 &preallocate_siginfo, 0, "Preallocated signal memory size");
144
145 static int signal_overflow = 0;
146 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
147 &signal_overflow, 0, "Number of signals overflew");
148
149 static int signal_alloc_fail = 0;
150 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
151 &signal_alloc_fail, 0, "signals failed to be allocated");
152
153 static int kern_lognosys = 0;
154 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
155 "Log invalid syscalls");
156
157 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
158
159 /*
160 * Policy -- Can ucred cr1 send SIGIO to process cr2?
161 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
162 * in the right situations.
163 */
164 #define CANSIGIO(cr1, cr2) \
165 ((cr1)->cr_uid == 0 || \
166 (cr1)->cr_ruid == (cr2)->cr_ruid || \
167 (cr1)->cr_uid == (cr2)->cr_ruid || \
168 (cr1)->cr_ruid == (cr2)->cr_uid || \
169 (cr1)->cr_uid == (cr2)->cr_uid)
170
171 static int sugid_coredump;
172 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN,
173 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
174
175 static int capmode_coredump;
176 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN,
177 &capmode_coredump, 0, "Allow processes in capability mode to dump core");
178
179 static int do_coredump = 1;
180 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
181 &do_coredump, 0, "Enable/Disable coredumps");
182
183 static int set_core_nodump_flag = 0;
184 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
185 0, "Enable setting the NODUMP flag on coredump files");
186
187 static int coredump_devctl = 0;
188 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
189 0, "Generate a devctl notification when processes coredump");
190
191 /*
192 * Signal properties and actions.
193 * The array below categorizes the signals and their default actions
194 * according to the following properties:
195 */
196 #define SA_KILL 0x01 /* terminates process by default */
197 #define SA_CORE 0x02 /* ditto and coredumps */
198 #define SA_STOP 0x04 /* suspend process */
199 #define SA_TTYSTOP 0x08 /* ditto, from tty */
200 #define SA_IGNORE 0x10 /* ignore by default */
201 #define SA_CONT 0x20 /* continue if suspended */
202 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
203
204 static int sigproptbl[NSIG] = {
205 SA_KILL, /* SIGHUP */
206 SA_KILL, /* SIGINT */
207 SA_KILL|SA_CORE, /* SIGQUIT */
208 SA_KILL|SA_CORE, /* SIGILL */
209 SA_KILL|SA_CORE, /* SIGTRAP */
210 SA_KILL|SA_CORE, /* SIGABRT */
211 SA_KILL|SA_CORE, /* SIGEMT */
212 SA_KILL|SA_CORE, /* SIGFPE */
213 SA_KILL, /* SIGKILL */
214 SA_KILL|SA_CORE, /* SIGBUS */
215 SA_KILL|SA_CORE, /* SIGSEGV */
216 SA_KILL|SA_CORE, /* SIGSYS */
217 SA_KILL, /* SIGPIPE */
218 SA_KILL, /* SIGALRM */
219 SA_KILL, /* SIGTERM */
220 SA_IGNORE, /* SIGURG */
221 SA_STOP, /* SIGSTOP */
222 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
223 SA_IGNORE|SA_CONT, /* SIGCONT */
224 SA_IGNORE, /* SIGCHLD */
225 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
226 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
227 SA_IGNORE, /* SIGIO */
228 SA_KILL, /* SIGXCPU */
229 SA_KILL, /* SIGXFSZ */
230 SA_KILL, /* SIGVTALRM */
231 SA_KILL, /* SIGPROF */
232 SA_IGNORE, /* SIGWINCH */
233 SA_IGNORE, /* SIGINFO */
234 SA_KILL, /* SIGUSR1 */
235 SA_KILL, /* SIGUSR2 */
236 };
237
238 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
239
240 static void
241 sigqueue_start(void)
242 {
243 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
244 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
245 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
246 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
247 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
248 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
249 }
250
251 ksiginfo_t *
252 ksiginfo_alloc(int wait)
253 {
254 int flags;
255
256 flags = M_ZERO;
257 if (! wait)
258 flags |= M_NOWAIT;
259 if (ksiginfo_zone != NULL)
260 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
261 return (NULL);
262 }
263
264 void
265 ksiginfo_free(ksiginfo_t *ksi)
266 {
267 uma_zfree(ksiginfo_zone, ksi);
268 }
269
270 static __inline int
271 ksiginfo_tryfree(ksiginfo_t *ksi)
272 {
273 if (!(ksi->ksi_flags & KSI_EXT)) {
274 uma_zfree(ksiginfo_zone, ksi);
275 return (1);
276 }
277 return (0);
278 }
279
280 void
281 sigqueue_init(sigqueue_t *list, struct proc *p)
282 {
283 SIGEMPTYSET(list->sq_signals);
284 SIGEMPTYSET(list->sq_kill);
285 SIGEMPTYSET(list->sq_ptrace);
286 TAILQ_INIT(&list->sq_list);
287 list->sq_proc = p;
288 list->sq_flags = SQ_INIT;
289 }
290
291 /*
292 * Get a signal's ksiginfo.
293 * Return:
294 * 0 - signal not found
295 * others - signal number
296 */
297 static int
298 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
299 {
300 struct proc *p = sq->sq_proc;
301 struct ksiginfo *ksi, *next;
302 int count = 0;
303
304 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
305
306 if (!SIGISMEMBER(sq->sq_signals, signo))
307 return (0);
308
309 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
310 count++;
311 SIGDELSET(sq->sq_ptrace, signo);
312 si->ksi_flags |= KSI_PTRACE;
313 }
314 if (SIGISMEMBER(sq->sq_kill, signo)) {
315 count++;
316 if (count == 1)
317 SIGDELSET(sq->sq_kill, signo);
318 }
319
320 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
321 if (ksi->ksi_signo == signo) {
322 if (count == 0) {
323 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
324 ksi->ksi_sigq = NULL;
325 ksiginfo_copy(ksi, si);
326 if (ksiginfo_tryfree(ksi) && p != NULL)
327 p->p_pendingcnt--;
328 }
329 if (++count > 1)
330 break;
331 }
332 }
333
334 if (count <= 1)
335 SIGDELSET(sq->sq_signals, signo);
336 si->ksi_signo = signo;
337 return (signo);
338 }
339
340 void
341 sigqueue_take(ksiginfo_t *ksi)
342 {
343 struct ksiginfo *kp;
344 struct proc *p;
345 sigqueue_t *sq;
346
347 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
348 return;
349
350 p = sq->sq_proc;
351 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
352 ksi->ksi_sigq = NULL;
353 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
354 p->p_pendingcnt--;
355
356 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
357 kp = TAILQ_NEXT(kp, ksi_link)) {
358 if (kp->ksi_signo == ksi->ksi_signo)
359 break;
360 }
361 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
362 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
363 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
364 }
365
366 static int
367 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
368 {
369 struct proc *p = sq->sq_proc;
370 struct ksiginfo *ksi;
371 int ret = 0;
372
373 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
374
375 /*
376 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
377 * for these signals.
378 */
379 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
380 SIGADDSET(sq->sq_kill, signo);
381 goto out_set_bit;
382 }
383
384 /* directly insert the ksi, don't copy it */
385 if (si->ksi_flags & KSI_INS) {
386 if (si->ksi_flags & KSI_HEAD)
387 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
388 else
389 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
390 si->ksi_sigq = sq;
391 goto out_set_bit;
392 }
393
394 if (__predict_false(ksiginfo_zone == NULL)) {
395 SIGADDSET(sq->sq_kill, signo);
396 goto out_set_bit;
397 }
398
399 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
400 signal_overflow++;
401 ret = EAGAIN;
402 } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
403 signal_alloc_fail++;
404 ret = EAGAIN;
405 } else {
406 if (p != NULL)
407 p->p_pendingcnt++;
408 ksiginfo_copy(si, ksi);
409 ksi->ksi_signo = signo;
410 if (si->ksi_flags & KSI_HEAD)
411 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
412 else
413 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
414 ksi->ksi_sigq = sq;
415 }
416
417 if (ret != 0) {
418 if ((si->ksi_flags & KSI_PTRACE) != 0) {
419 SIGADDSET(sq->sq_ptrace, signo);
420 ret = 0;
421 goto out_set_bit;
422 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
423 (si->ksi_flags & KSI_SIGQ) == 0) {
424 SIGADDSET(sq->sq_kill, signo);
425 ret = 0;
426 goto out_set_bit;
427 }
428 return (ret);
429 }
430
431 out_set_bit:
432 SIGADDSET(sq->sq_signals, signo);
433 return (ret);
434 }
435
436 void
437 sigqueue_flush(sigqueue_t *sq)
438 {
439 struct proc *p = sq->sq_proc;
440 ksiginfo_t *ksi;
441
442 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
443
444 if (p != NULL)
445 PROC_LOCK_ASSERT(p, MA_OWNED);
446
447 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
448 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
449 ksi->ksi_sigq = NULL;
450 if (ksiginfo_tryfree(ksi) && p != NULL)
451 p->p_pendingcnt--;
452 }
453
454 SIGEMPTYSET(sq->sq_signals);
455 SIGEMPTYSET(sq->sq_kill);
456 SIGEMPTYSET(sq->sq_ptrace);
457 }
458
459 static void
460 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
461 {
462 sigset_t tmp;
463 struct proc *p1, *p2;
464 ksiginfo_t *ksi, *next;
465
466 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
467 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
468 p1 = src->sq_proc;
469 p2 = dst->sq_proc;
470 /* Move siginfo to target list */
471 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
472 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
473 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
474 if (p1 != NULL)
475 p1->p_pendingcnt--;
476 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
477 ksi->ksi_sigq = dst;
478 if (p2 != NULL)
479 p2->p_pendingcnt++;
480 }
481 }
482
483 /* Move pending bits to target list */
484 tmp = src->sq_kill;
485 SIGSETAND(tmp, *set);
486 SIGSETOR(dst->sq_kill, tmp);
487 SIGSETNAND(src->sq_kill, tmp);
488
489 tmp = src->sq_ptrace;
490 SIGSETAND(tmp, *set);
491 SIGSETOR(dst->sq_ptrace, tmp);
492 SIGSETNAND(src->sq_ptrace, tmp);
493
494 tmp = src->sq_signals;
495 SIGSETAND(tmp, *set);
496 SIGSETOR(dst->sq_signals, tmp);
497 SIGSETNAND(src->sq_signals, tmp);
498 }
499
500 #if 0
501 static void
502 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
503 {
504 sigset_t set;
505
506 SIGEMPTYSET(set);
507 SIGADDSET(set, signo);
508 sigqueue_move_set(src, dst, &set);
509 }
510 #endif
511
512 static void
513 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
514 {
515 struct proc *p = sq->sq_proc;
516 ksiginfo_t *ksi, *next;
517
518 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
519
520 /* Remove siginfo queue */
521 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
522 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
523 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
524 ksi->ksi_sigq = NULL;
525 if (ksiginfo_tryfree(ksi) && p != NULL)
526 p->p_pendingcnt--;
527 }
528 }
529 SIGSETNAND(sq->sq_kill, *set);
530 SIGSETNAND(sq->sq_ptrace, *set);
531 SIGSETNAND(sq->sq_signals, *set);
532 }
533
534 void
535 sigqueue_delete(sigqueue_t *sq, int signo)
536 {
537 sigset_t set;
538
539 SIGEMPTYSET(set);
540 SIGADDSET(set, signo);
541 sigqueue_delete_set(sq, &set);
542 }
543
544 /* Remove a set of signals for a process */
545 static void
546 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
547 {
548 sigqueue_t worklist;
549 struct thread *td0;
550
551 PROC_LOCK_ASSERT(p, MA_OWNED);
552
553 sigqueue_init(&worklist, NULL);
554 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
555
556 FOREACH_THREAD_IN_PROC(p, td0)
557 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
558
559 sigqueue_flush(&worklist);
560 }
561
562 void
563 sigqueue_delete_proc(struct proc *p, int signo)
564 {
565 sigset_t set;
566
567 SIGEMPTYSET(set);
568 SIGADDSET(set, signo);
569 sigqueue_delete_set_proc(p, &set);
570 }
571
572 static void
573 sigqueue_delete_stopmask_proc(struct proc *p)
574 {
575 sigset_t set;
576
577 SIGEMPTYSET(set);
578 SIGADDSET(set, SIGSTOP);
579 SIGADDSET(set, SIGTSTP);
580 SIGADDSET(set, SIGTTIN);
581 SIGADDSET(set, SIGTTOU);
582 sigqueue_delete_set_proc(p, &set);
583 }
584
585 /*
586 * Determine signal that should be delivered to thread td, the current
587 * thread, 0 if none. If there is a pending stop signal with default
588 * action, the process stops in issignal().
589 */
590 int
591 cursig(struct thread *td)
592 {
593 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
594 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
595 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
596 return (SIGPENDING(td) ? issignal(td) : 0);
597 }
598
599 /*
600 * Arrange for ast() to handle unmasked pending signals on return to user
601 * mode. This must be called whenever a signal is added to td_sigqueue or
602 * unmasked in td_sigmask.
603 */
604 void
605 signotify(struct thread *td)
606 {
607 struct proc *p;
608
609 p = td->td_proc;
610
611 PROC_LOCK_ASSERT(p, MA_OWNED);
612
613 if (SIGPENDING(td)) {
614 thread_lock(td);
615 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
616 thread_unlock(td);
617 }
618 }
619
620 int
621 sigonstack(size_t sp)
622 {
623 struct thread *td = curthread;
624
625 return ((td->td_pflags & TDP_ALTSTACK) ?
626 #if defined(COMPAT_43)
627 ((td->td_sigstk.ss_size == 0) ?
628 (td->td_sigstk.ss_flags & SS_ONSTACK) :
629 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
630 #else
631 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
632 #endif
633 : 0);
634 }
635
636 static __inline int
637 sigprop(int sig)
638 {
639
640 if (sig > 0 && sig < NSIG)
641 return (sigproptbl[_SIG_IDX(sig)]);
642 return (0);
643 }
644
645 int
646 sig_ffs(sigset_t *set)
647 {
648 int i;
649
650 for (i = 0; i < _SIG_WORDS; i++)
651 if (set->__bits[i])
652 return (ffs(set->__bits[i]) + (i * 32));
653 return (0);
654 }
655
656 static bool
657 sigact_flag_test(const struct sigaction *act, int flag)
658 {
659
660 /*
661 * SA_SIGINFO is reset when signal disposition is set to
662 * ignore or default. Other flags are kept according to user
663 * settings.
664 */
665 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
666 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
667 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
668 }
669
670 /*
671 * kern_sigaction
672 * sigaction
673 * freebsd4_sigaction
674 * osigaction
675 */
676 int
677 kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
678 struct sigaction *oact, int flags)
679 {
680 struct sigacts *ps;
681 struct proc *p = td->td_proc;
682
683 if (!_SIG_VALID(sig))
684 return (EINVAL);
685 if (act != NULL && act->sa_handler != SIG_DFL &&
686 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
687 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
688 SA_NOCLDWAIT | SA_SIGINFO)) != 0)
689 return (EINVAL);
690
691 PROC_LOCK(p);
692 ps = p->p_sigacts;
693 mtx_lock(&ps->ps_mtx);
694 if (oact) {
695 memset(oact, 0, sizeof(*oact));
696 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
697 if (SIGISMEMBER(ps->ps_sigonstack, sig))
698 oact->sa_flags |= SA_ONSTACK;
699 if (!SIGISMEMBER(ps->ps_sigintr, sig))
700 oact->sa_flags |= SA_RESTART;
701 if (SIGISMEMBER(ps->ps_sigreset, sig))
702 oact->sa_flags |= SA_RESETHAND;
703 if (SIGISMEMBER(ps->ps_signodefer, sig))
704 oact->sa_flags |= SA_NODEFER;
705 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
706 oact->sa_flags |= SA_SIGINFO;
707 oact->sa_sigaction =
708 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
709 } else
710 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
711 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
712 oact->sa_flags |= SA_NOCLDSTOP;
713 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
714 oact->sa_flags |= SA_NOCLDWAIT;
715 }
716 if (act) {
717 if ((sig == SIGKILL || sig == SIGSTOP) &&
718 act->sa_handler != SIG_DFL) {
719 mtx_unlock(&ps->ps_mtx);
720 PROC_UNLOCK(p);
721 return (EINVAL);
722 }
723
724 /*
725 * Change setting atomically.
726 */
727
728 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
729 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
730 if (sigact_flag_test(act, SA_SIGINFO)) {
731 ps->ps_sigact[_SIG_IDX(sig)] =
732 (__sighandler_t *)act->sa_sigaction;
733 SIGADDSET(ps->ps_siginfo, sig);
734 } else {
735 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
736 SIGDELSET(ps->ps_siginfo, sig);
737 }
738 if (!sigact_flag_test(act, SA_RESTART))
739 SIGADDSET(ps->ps_sigintr, sig);
740 else
741 SIGDELSET(ps->ps_sigintr, sig);
742 if (sigact_flag_test(act, SA_ONSTACK))
743 SIGADDSET(ps->ps_sigonstack, sig);
744 else
745 SIGDELSET(ps->ps_sigonstack, sig);
746 if (sigact_flag_test(act, SA_RESETHAND))
747 SIGADDSET(ps->ps_sigreset, sig);
748 else
749 SIGDELSET(ps->ps_sigreset, sig);
750 if (sigact_flag_test(act, SA_NODEFER))
751 SIGADDSET(ps->ps_signodefer, sig);
752 else
753 SIGDELSET(ps->ps_signodefer, sig);
754 if (sig == SIGCHLD) {
755 if (act->sa_flags & SA_NOCLDSTOP)
756 ps->ps_flag |= PS_NOCLDSTOP;
757 else
758 ps->ps_flag &= ~PS_NOCLDSTOP;
759 if (act->sa_flags & SA_NOCLDWAIT) {
760 /*
761 * Paranoia: since SA_NOCLDWAIT is implemented
762 * by reparenting the dying child to PID 1 (and
763 * trust it to reap the zombie), PID 1 itself
764 * is forbidden to set SA_NOCLDWAIT.
765 */
766 if (p->p_pid == 1)
767 ps->ps_flag &= ~PS_NOCLDWAIT;
768 else
769 ps->ps_flag |= PS_NOCLDWAIT;
770 } else
771 ps->ps_flag &= ~PS_NOCLDWAIT;
772 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
773 ps->ps_flag |= PS_CLDSIGIGN;
774 else
775 ps->ps_flag &= ~PS_CLDSIGIGN;
776 }
777 /*
778 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
779 * and for signals set to SIG_DFL where the default is to
780 * ignore. However, don't put SIGCONT in ps_sigignore, as we
781 * have to restart the process.
782 */
783 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
784 (sigprop(sig) & SA_IGNORE &&
785 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
786 /* never to be seen again */
787 sigqueue_delete_proc(p, sig);
788 if (sig != SIGCONT)
789 /* easier in psignal */
790 SIGADDSET(ps->ps_sigignore, sig);
791 SIGDELSET(ps->ps_sigcatch, sig);
792 } else {
793 SIGDELSET(ps->ps_sigignore, sig);
794 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
795 SIGDELSET(ps->ps_sigcatch, sig);
796 else
797 SIGADDSET(ps->ps_sigcatch, sig);
798 }
799 #ifdef COMPAT_FREEBSD4
800 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
801 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
802 (flags & KSA_FREEBSD4) == 0)
803 SIGDELSET(ps->ps_freebsd4, sig);
804 else
805 SIGADDSET(ps->ps_freebsd4, sig);
806 #endif
807 #ifdef COMPAT_43
808 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
809 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
810 (flags & KSA_OSIGSET) == 0)
811 SIGDELSET(ps->ps_osigset, sig);
812 else
813 SIGADDSET(ps->ps_osigset, sig);
814 #endif
815 }
816 mtx_unlock(&ps->ps_mtx);
817 PROC_UNLOCK(p);
818 return (0);
819 }
820
821 #ifndef _SYS_SYSPROTO_H_
822 struct sigaction_args {
823 int sig;
824 struct sigaction *act;
825 struct sigaction *oact;
826 };
827 #endif
828 int
829 sys_sigaction(struct thread *td, struct sigaction_args *uap)
830 {
831 struct sigaction act, oact;
832 struct sigaction *actp, *oactp;
833 int error;
834
835 actp = (uap->act != NULL) ? &act : NULL;
836 oactp = (uap->oact != NULL) ? &oact : NULL;
837 if (actp) {
838 error = copyin(uap->act, actp, sizeof(act));
839 if (error)
840 return (error);
841 }
842 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
843 if (oactp && !error)
844 error = copyout(oactp, uap->oact, sizeof(oact));
845 return (error);
846 }
847
848 #ifdef COMPAT_FREEBSD4
849 #ifndef _SYS_SYSPROTO_H_
850 struct freebsd4_sigaction_args {
851 int sig;
852 struct sigaction *act;
853 struct sigaction *oact;
854 };
855 #endif
856 int
857 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
858 {
859 struct sigaction act, oact;
860 struct sigaction *actp, *oactp;
861 int error;
862
863
864 actp = (uap->act != NULL) ? &act : NULL;
865 oactp = (uap->oact != NULL) ? &oact : NULL;
866 if (actp) {
867 error = copyin(uap->act, actp, sizeof(act));
868 if (error)
869 return (error);
870 }
871 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
872 if (oactp && !error)
873 error = copyout(oactp, uap->oact, sizeof(oact));
874 return (error);
875 }
876 #endif /* COMAPT_FREEBSD4 */
877
878 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
879 #ifndef _SYS_SYSPROTO_H_
880 struct osigaction_args {
881 int signum;
882 struct osigaction *nsa;
883 struct osigaction *osa;
884 };
885 #endif
886 int
887 osigaction(struct thread *td, struct osigaction_args *uap)
888 {
889 struct osigaction sa;
890 struct sigaction nsa, osa;
891 struct sigaction *nsap, *osap;
892 int error;
893
894 if (uap->signum <= 0 || uap->signum >= ONSIG)
895 return (EINVAL);
896
897 nsap = (uap->nsa != NULL) ? &nsa : NULL;
898 osap = (uap->osa != NULL) ? &osa : NULL;
899
900 if (nsap) {
901 error = copyin(uap->nsa, &sa, sizeof(sa));
902 if (error)
903 return (error);
904 nsap->sa_handler = sa.sa_handler;
905 nsap->sa_flags = sa.sa_flags;
906 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
907 }
908 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
909 if (osap && !error) {
910 sa.sa_handler = osap->sa_handler;
911 sa.sa_flags = osap->sa_flags;
912 SIG2OSIG(osap->sa_mask, sa.sa_mask);
913 error = copyout(&sa, uap->osa, sizeof(sa));
914 }
915 return (error);
916 }
917
918 #if !defined(__i386__)
919 /* Avoid replicating the same stub everywhere */
920 int
921 osigreturn(struct thread *td, struct osigreturn_args *uap)
922 {
923
924 return (nosys(td, (struct nosys_args *)uap));
925 }
926 #endif
927 #endif /* COMPAT_43 */
928
929 /*
930 * Initialize signal state for process 0;
931 * set to ignore signals that are ignored by default.
932 */
933 void
934 siginit(struct proc *p)
935 {
936 int i;
937 struct sigacts *ps;
938
939 PROC_LOCK(p);
940 ps = p->p_sigacts;
941 mtx_lock(&ps->ps_mtx);
942 for (i = 1; i <= NSIG; i++) {
943 if (sigprop(i) & SA_IGNORE && i != SIGCONT) {
944 SIGADDSET(ps->ps_sigignore, i);
945 }
946 }
947 mtx_unlock(&ps->ps_mtx);
948 PROC_UNLOCK(p);
949 }
950
951 /*
952 * Reset specified signal to the default disposition.
953 */
954 static void
955 sigdflt(struct sigacts *ps, int sig)
956 {
957
958 mtx_assert(&ps->ps_mtx, MA_OWNED);
959 SIGDELSET(ps->ps_sigcatch, sig);
960 if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT)
961 SIGADDSET(ps->ps_sigignore, sig);
962 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
963 SIGDELSET(ps->ps_siginfo, sig);
964 }
965
966 /*
967 * Reset signals for an exec of the specified process.
968 */
969 void
970 execsigs(struct proc *p)
971 {
972 sigset_t osigignore;
973 struct sigacts *ps;
974 int sig;
975 struct thread *td;
976
977 /*
978 * Reset caught signals. Held signals remain held
979 * through td_sigmask (unless they were caught,
980 * and are now ignored by default).
981 */
982 PROC_LOCK_ASSERT(p, MA_OWNED);
983 ps = p->p_sigacts;
984 mtx_lock(&ps->ps_mtx);
985 while (SIGNOTEMPTY(ps->ps_sigcatch)) {
986 sig = sig_ffs(&ps->ps_sigcatch);
987 sigdflt(ps, sig);
988 if ((sigprop(sig) & SA_IGNORE) != 0)
989 sigqueue_delete_proc(p, sig);
990 }
991
992 /*
993 * As CloudABI processes cannot modify signal handlers, fully
994 * reset all signals to their default behavior. Do ignore
995 * SIGPIPE, as it would otherwise be impossible to recover from
996 * writes to broken pipes and sockets.
997 */
998 if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) {
999 osigignore = ps->ps_sigignore;
1000 while (SIGNOTEMPTY(osigignore)) {
1001 sig = sig_ffs(&osigignore);
1002 SIGDELSET(osigignore, sig);
1003 if (sig != SIGPIPE)
1004 sigdflt(ps, sig);
1005 }
1006 SIGADDSET(ps->ps_sigignore, SIGPIPE);
1007 }
1008
1009 /*
1010 * Reset stack state to the user stack.
1011 * Clear set of signals caught on the signal stack.
1012 */
1013 td = curthread;
1014 MPASS(td->td_proc == p);
1015 td->td_sigstk.ss_flags = SS_DISABLE;
1016 td->td_sigstk.ss_size = 0;
1017 td->td_sigstk.ss_sp = 0;
1018 td->td_pflags &= ~TDP_ALTSTACK;
1019 /*
1020 * Reset no zombies if child dies flag as Solaris does.
1021 */
1022 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1023 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1024 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1025 mtx_unlock(&ps->ps_mtx);
1026 }
1027
1028 /*
1029 * kern_sigprocmask()
1030 *
1031 * Manipulate signal mask.
1032 */
1033 int
1034 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1035 int flags)
1036 {
1037 sigset_t new_block, oset1;
1038 struct proc *p;
1039 int error;
1040
1041 p = td->td_proc;
1042 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1043 PROC_LOCK_ASSERT(p, MA_OWNED);
1044 else
1045 PROC_LOCK(p);
1046 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1047 ? MA_OWNED : MA_NOTOWNED);
1048 if (oset != NULL)
1049 *oset = td->td_sigmask;
1050
1051 error = 0;
1052 if (set != NULL) {
1053 switch (how) {
1054 case SIG_BLOCK:
1055 SIG_CANTMASK(*set);
1056 oset1 = td->td_sigmask;
1057 SIGSETOR(td->td_sigmask, *set);
1058 new_block = td->td_sigmask;
1059 SIGSETNAND(new_block, oset1);
1060 break;
1061 case SIG_UNBLOCK:
1062 SIGSETNAND(td->td_sigmask, *set);
1063 signotify(td);
1064 goto out;
1065 case SIG_SETMASK:
1066 SIG_CANTMASK(*set);
1067 oset1 = td->td_sigmask;
1068 if (flags & SIGPROCMASK_OLD)
1069 SIGSETLO(td->td_sigmask, *set);
1070 else
1071 td->td_sigmask = *set;
1072 new_block = td->td_sigmask;
1073 SIGSETNAND(new_block, oset1);
1074 signotify(td);
1075 break;
1076 default:
1077 error = EINVAL;
1078 goto out;
1079 }
1080
1081 /*
1082 * The new_block set contains signals that were not previously
1083 * blocked, but are blocked now.
1084 *
1085 * In case we block any signal that was not previously blocked
1086 * for td, and process has the signal pending, try to schedule
1087 * signal delivery to some thread that does not block the
1088 * signal, possibly waking it up.
1089 */
1090 if (p->p_numthreads != 1)
1091 reschedule_signals(p, new_block, flags);
1092 }
1093
1094 out:
1095 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1096 PROC_UNLOCK(p);
1097 return (error);
1098 }
1099
1100 #ifndef _SYS_SYSPROTO_H_
1101 struct sigprocmask_args {
1102 int how;
1103 const sigset_t *set;
1104 sigset_t *oset;
1105 };
1106 #endif
1107 int
1108 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
1109 {
1110 sigset_t set, oset;
1111 sigset_t *setp, *osetp;
1112 int error;
1113
1114 setp = (uap->set != NULL) ? &set : NULL;
1115 osetp = (uap->oset != NULL) ? &oset : NULL;
1116 if (setp) {
1117 error = copyin(uap->set, setp, sizeof(set));
1118 if (error)
1119 return (error);
1120 }
1121 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1122 if (osetp && !error) {
1123 error = copyout(osetp, uap->oset, sizeof(oset));
1124 }
1125 return (error);
1126 }
1127
1128 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1129 #ifndef _SYS_SYSPROTO_H_
1130 struct osigprocmask_args {
1131 int how;
1132 osigset_t mask;
1133 };
1134 #endif
1135 int
1136 osigprocmask(struct thread *td, struct osigprocmask_args *uap)
1137 {
1138 sigset_t set, oset;
1139 int error;
1140
1141 OSIG2SIG(uap->mask, set);
1142 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1143 SIG2OSIG(oset, td->td_retval[0]);
1144 return (error);
1145 }
1146 #endif /* COMPAT_43 */
1147
1148 int
1149 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1150 {
1151 ksiginfo_t ksi;
1152 sigset_t set;
1153 int error;
1154
1155 error = copyin(uap->set, &set, sizeof(set));
1156 if (error) {
1157 td->td_retval[0] = error;
1158 return (0);
1159 }
1160
1161 error = kern_sigtimedwait(td, set, &ksi, NULL);
1162 if (error) {
1163 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1164 error = ERESTART;
1165 if (error == ERESTART)
1166 return (error);
1167 td->td_retval[0] = error;
1168 return (0);
1169 }
1170
1171 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1172 td->td_retval[0] = error;
1173 return (0);
1174 }
1175
1176 int
1177 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1178 {
1179 struct timespec ts;
1180 struct timespec *timeout;
1181 sigset_t set;
1182 ksiginfo_t ksi;
1183 int error;
1184
1185 if (uap->timeout) {
1186 error = copyin(uap->timeout, &ts, sizeof(ts));
1187 if (error)
1188 return (error);
1189
1190 timeout = &ts;
1191 } else
1192 timeout = NULL;
1193
1194 error = copyin(uap->set, &set, sizeof(set));
1195 if (error)
1196 return (error);
1197
1198 error = kern_sigtimedwait(td, set, &ksi, timeout);
1199 if (error)
1200 return (error);
1201
1202 if (uap->info)
1203 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1204
1205 if (error == 0)
1206 td->td_retval[0] = ksi.ksi_signo;
1207 return (error);
1208 }
1209
1210 int
1211 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1212 {
1213 ksiginfo_t ksi;
1214 sigset_t set;
1215 int error;
1216
1217 error = copyin(uap->set, &set, sizeof(set));
1218 if (error)
1219 return (error);
1220
1221 error = kern_sigtimedwait(td, set, &ksi, NULL);
1222 if (error)
1223 return (error);
1224
1225 if (uap->info)
1226 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1227
1228 if (error == 0)
1229 td->td_retval[0] = ksi.ksi_signo;
1230 return (error);
1231 }
1232
1233 static void
1234 proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
1235 {
1236 struct thread *thr;
1237
1238 FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
1239 if (thr == td)
1240 thr->td_si = *si;
1241 else
1242 thr->td_si.si_signo = 0;
1243 }
1244 }
1245
1246 int
1247 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1248 struct timespec *timeout)
1249 {
1250 struct sigacts *ps;
1251 sigset_t saved_mask, new_block;
1252 struct proc *p;
1253 int error, sig, timo, timevalid = 0;
1254 struct timespec rts, ets, ts;
1255 struct timeval tv;
1256
1257 p = td->td_proc;
1258 error = 0;
1259 ets.tv_sec = 0;
1260 ets.tv_nsec = 0;
1261
1262 if (timeout != NULL) {
1263 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1264 timevalid = 1;
1265 getnanouptime(&rts);
1266 ets = rts;
1267 timespecadd(&ets, timeout);
1268 }
1269 }
1270 ksiginfo_init(ksi);
1271 /* Some signals can not be waited for. */
1272 SIG_CANTMASK(waitset);
1273 ps = p->p_sigacts;
1274 PROC_LOCK(p);
1275 saved_mask = td->td_sigmask;
1276 SIGSETNAND(td->td_sigmask, waitset);
1277 for (;;) {
1278 mtx_lock(&ps->ps_mtx);
1279 sig = cursig(td);
1280 mtx_unlock(&ps->ps_mtx);
1281 KASSERT(sig >= 0, ("sig %d", sig));
1282 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1283 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1284 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1285 error = 0;
1286 break;
1287 }
1288 }
1289
1290 if (error != 0)
1291 break;
1292
1293 /*
1294 * POSIX says this must be checked after looking for pending
1295 * signals.
1296 */
1297 if (timeout != NULL) {
1298 if (!timevalid) {
1299 error = EINVAL;
1300 break;
1301 }
1302 getnanouptime(&rts);
1303 if (timespeccmp(&rts, &ets, >=)) {
1304 error = EAGAIN;
1305 break;
1306 }
1307 ts = ets;
1308 timespecsub(&ts, &rts);
1309 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1310 timo = tvtohz(&tv);
1311 } else {
1312 timo = 0;
1313 }
1314
1315 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
1316
1317 if (timeout != NULL) {
1318 if (error == ERESTART) {
1319 /* Timeout can not be restarted. */
1320 error = EINTR;
1321 } else if (error == EAGAIN) {
1322 /* We will calculate timeout by ourself. */
1323 error = 0;
1324 }
1325 }
1326 }
1327
1328 new_block = saved_mask;
1329 SIGSETNAND(new_block, td->td_sigmask);
1330 td->td_sigmask = saved_mask;
1331 /*
1332 * Fewer signals can be delivered to us, reschedule signal
1333 * notification.
1334 */
1335 if (p->p_numthreads != 1)
1336 reschedule_signals(p, new_block, 0);
1337
1338 if (error == 0) {
1339 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1340
1341 if (ksi->ksi_code == SI_TIMER)
1342 itimer_accept(p, ksi->ksi_timerid, ksi);
1343
1344 #ifdef KTRACE
1345 if (KTRPOINT(td, KTR_PSIG)) {
1346 sig_t action;
1347
1348 mtx_lock(&ps->ps_mtx);
1349 action = ps->ps_sigact[_SIG_IDX(sig)];
1350 mtx_unlock(&ps->ps_mtx);
1351 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1352 }
1353 #endif
1354 if (sig == SIGKILL) {
1355 proc_td_siginfo_capture(td, &ksi->ksi_info);
1356 sigexit(td, sig);
1357 }
1358 }
1359 PROC_UNLOCK(p);
1360 return (error);
1361 }
1362
1363 #ifndef _SYS_SYSPROTO_H_
1364 struct sigpending_args {
1365 sigset_t *set;
1366 };
1367 #endif
1368 int
1369 sys_sigpending(struct thread *td, struct sigpending_args *uap)
1370 {
1371 struct proc *p = td->td_proc;
1372 sigset_t pending;
1373
1374 PROC_LOCK(p);
1375 pending = p->p_sigqueue.sq_signals;
1376 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1377 PROC_UNLOCK(p);
1378 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1379 }
1380
1381 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1382 #ifndef _SYS_SYSPROTO_H_
1383 struct osigpending_args {
1384 int dummy;
1385 };
1386 #endif
1387 int
1388 osigpending(struct thread *td, struct osigpending_args *uap)
1389 {
1390 struct proc *p = td->td_proc;
1391 sigset_t pending;
1392
1393 PROC_LOCK(p);
1394 pending = p->p_sigqueue.sq_signals;
1395 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1396 PROC_UNLOCK(p);
1397 SIG2OSIG(pending, td->td_retval[0]);
1398 return (0);
1399 }
1400 #endif /* COMPAT_43 */
1401
1402 #if defined(COMPAT_43)
1403 /*
1404 * Generalized interface signal handler, 4.3-compatible.
1405 */
1406 #ifndef _SYS_SYSPROTO_H_
1407 struct osigvec_args {
1408 int signum;
1409 struct sigvec *nsv;
1410 struct sigvec *osv;
1411 };
1412 #endif
1413 /* ARGSUSED */
1414 int
1415 osigvec(struct thread *td, struct osigvec_args *uap)
1416 {
1417 struct sigvec vec;
1418 struct sigaction nsa, osa;
1419 struct sigaction *nsap, *osap;
1420 int error;
1421
1422 if (uap->signum <= 0 || uap->signum >= ONSIG)
1423 return (EINVAL);
1424 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1425 osap = (uap->osv != NULL) ? &osa : NULL;
1426 if (nsap) {
1427 error = copyin(uap->nsv, &vec, sizeof(vec));
1428 if (error)
1429 return (error);
1430 nsap->sa_handler = vec.sv_handler;
1431 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1432 nsap->sa_flags = vec.sv_flags;
1433 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1434 }
1435 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1436 if (osap && !error) {
1437 vec.sv_handler = osap->sa_handler;
1438 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1439 vec.sv_flags = osap->sa_flags;
1440 vec.sv_flags &= ~SA_NOCLDWAIT;
1441 vec.sv_flags ^= SA_RESTART;
1442 error = copyout(&vec, uap->osv, sizeof(vec));
1443 }
1444 return (error);
1445 }
1446
1447 #ifndef _SYS_SYSPROTO_H_
1448 struct osigblock_args {
1449 int mask;
1450 };
1451 #endif
1452 int
1453 osigblock(struct thread *td, struct osigblock_args *uap)
1454 {
1455 sigset_t set, oset;
1456
1457 OSIG2SIG(uap->mask, set);
1458 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1459 SIG2OSIG(oset, td->td_retval[0]);
1460 return (0);
1461 }
1462
1463 #ifndef _SYS_SYSPROTO_H_
1464 struct osigsetmask_args {
1465 int mask;
1466 };
1467 #endif
1468 int
1469 osigsetmask(struct thread *td, struct osigsetmask_args *uap)
1470 {
1471 sigset_t set, oset;
1472
1473 OSIG2SIG(uap->mask, set);
1474 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1475 SIG2OSIG(oset, td->td_retval[0]);
1476 return (0);
1477 }
1478 #endif /* COMPAT_43 */
1479
1480 /*
1481 * Suspend calling thread until signal, providing mask to be set in the
1482 * meantime.
1483 */
1484 #ifndef _SYS_SYSPROTO_H_
1485 struct sigsuspend_args {
1486 const sigset_t *sigmask;
1487 };
1488 #endif
1489 /* ARGSUSED */
1490 int
1491 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
1492 {
1493 sigset_t mask;
1494 int error;
1495
1496 error = copyin(uap->sigmask, &mask, sizeof(mask));
1497 if (error)
1498 return (error);
1499 return (kern_sigsuspend(td, mask));
1500 }
1501
1502 int
1503 kern_sigsuspend(struct thread *td, sigset_t mask)
1504 {
1505 struct proc *p = td->td_proc;
1506 int has_sig, sig;
1507
1508 /*
1509 * When returning from sigsuspend, we want
1510 * the old mask to be restored after the
1511 * signal handler has finished. Thus, we
1512 * save it here and mark the sigacts structure
1513 * to indicate this.
1514 */
1515 PROC_LOCK(p);
1516 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1517 SIGPROCMASK_PROC_LOCKED);
1518 td->td_pflags |= TDP_OLDMASK;
1519
1520 /*
1521 * Process signals now. Otherwise, we can get spurious wakeup
1522 * due to signal entered process queue, but delivered to other
1523 * thread. But sigsuspend should return only on signal
1524 * delivery.
1525 */
1526 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1527 for (has_sig = 0; !has_sig;) {
1528 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1529 0) == 0)
1530 /* void */;
1531 thread_suspend_check(0);
1532 mtx_lock(&p->p_sigacts->ps_mtx);
1533 while ((sig = cursig(td)) != 0) {
1534 KASSERT(sig >= 0, ("sig %d", sig));
1535 has_sig += postsig(sig);
1536 }
1537 mtx_unlock(&p->p_sigacts->ps_mtx);
1538 }
1539 PROC_UNLOCK(p);
1540 td->td_errno = EINTR;
1541 td->td_pflags |= TDP_NERRNO;
1542 return (EJUSTRETURN);
1543 }
1544
1545 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1546 /*
1547 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1548 * convention: libc stub passes mask, not pointer, to save a copyin.
1549 */
1550 #ifndef _SYS_SYSPROTO_H_
1551 struct osigsuspend_args {
1552 osigset_t mask;
1553 };
1554 #endif
1555 /* ARGSUSED */
1556 int
1557 osigsuspend(struct thread *td, struct osigsuspend_args *uap)
1558 {
1559 sigset_t mask;
1560
1561 OSIG2SIG(uap->mask, mask);
1562 return (kern_sigsuspend(td, mask));
1563 }
1564 #endif /* COMPAT_43 */
1565
1566 #if defined(COMPAT_43)
1567 #ifndef _SYS_SYSPROTO_H_
1568 struct osigstack_args {
1569 struct sigstack *nss;
1570 struct sigstack *oss;
1571 };
1572 #endif
1573 /* ARGSUSED */
1574 int
1575 osigstack(struct thread *td, struct osigstack_args *uap)
1576 {
1577 struct sigstack nss, oss;
1578 int error = 0;
1579
1580 if (uap->nss != NULL) {
1581 error = copyin(uap->nss, &nss, sizeof(nss));
1582 if (error)
1583 return (error);
1584 }
1585 oss.ss_sp = td->td_sigstk.ss_sp;
1586 oss.ss_onstack = sigonstack(cpu_getstack(td));
1587 if (uap->nss != NULL) {
1588 td->td_sigstk.ss_sp = nss.ss_sp;
1589 td->td_sigstk.ss_size = 0;
1590 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1591 td->td_pflags |= TDP_ALTSTACK;
1592 }
1593 if (uap->oss != NULL)
1594 error = copyout(&oss, uap->oss, sizeof(oss));
1595
1596 return (error);
1597 }
1598 #endif /* COMPAT_43 */
1599
1600 #ifndef _SYS_SYSPROTO_H_
1601 struct sigaltstack_args {
1602 stack_t *ss;
1603 stack_t *oss;
1604 };
1605 #endif
1606 /* ARGSUSED */
1607 int
1608 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
1609 {
1610 stack_t ss, oss;
1611 int error;
1612
1613 if (uap->ss != NULL) {
1614 error = copyin(uap->ss, &ss, sizeof(ss));
1615 if (error)
1616 return (error);
1617 }
1618 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1619 (uap->oss != NULL) ? &oss : NULL);
1620 if (error)
1621 return (error);
1622 if (uap->oss != NULL)
1623 error = copyout(&oss, uap->oss, sizeof(stack_t));
1624 return (error);
1625 }
1626
1627 int
1628 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1629 {
1630 struct proc *p = td->td_proc;
1631 int oonstack;
1632
1633 oonstack = sigonstack(cpu_getstack(td));
1634
1635 if (oss != NULL) {
1636 *oss = td->td_sigstk;
1637 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1638 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1639 }
1640
1641 if (ss != NULL) {
1642 if (oonstack)
1643 return (EPERM);
1644 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1645 return (EINVAL);
1646 if (!(ss->ss_flags & SS_DISABLE)) {
1647 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1648 return (ENOMEM);
1649
1650 td->td_sigstk = *ss;
1651 td->td_pflags |= TDP_ALTSTACK;
1652 } else {
1653 td->td_pflags &= ~TDP_ALTSTACK;
1654 }
1655 }
1656 return (0);
1657 }
1658
1659 /*
1660 * Common code for kill process group/broadcast kill.
1661 * cp is calling process.
1662 */
1663 static int
1664 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1665 {
1666 struct proc *p;
1667 struct pgrp *pgrp;
1668 int err;
1669 int ret;
1670
1671 ret = ESRCH;
1672 if (all) {
1673 /*
1674 * broadcast
1675 */
1676 sx_slock(&allproc_lock);
1677 FOREACH_PROC_IN_SYSTEM(p) {
1678 PROC_LOCK(p);
1679 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1680 p == td->td_proc || p->p_state == PRS_NEW) {
1681 PROC_UNLOCK(p);
1682 continue;
1683 }
1684 err = p_cansignal(td, p, sig);
1685 if (err == 0) {
1686 if (sig)
1687 pksignal(p, sig, ksi);
1688 ret = err;
1689 }
1690 else if (ret == ESRCH)
1691 ret = err;
1692 PROC_UNLOCK(p);
1693 }
1694 sx_sunlock(&allproc_lock);
1695 } else {
1696 sx_slock(&proctree_lock);
1697 if (pgid == 0) {
1698 /*
1699 * zero pgid means send to my process group.
1700 */
1701 pgrp = td->td_proc->p_pgrp;
1702 PGRP_LOCK(pgrp);
1703 } else {
1704 pgrp = pgfind(pgid);
1705 if (pgrp == NULL) {
1706 sx_sunlock(&proctree_lock);
1707 return (ESRCH);
1708 }
1709 }
1710 sx_sunlock(&proctree_lock);
1711 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1712 PROC_LOCK(p);
1713 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1714 p->p_state == PRS_NEW) {
1715 PROC_UNLOCK(p);
1716 continue;
1717 }
1718 err = p_cansignal(td, p, sig);
1719 if (err == 0) {
1720 if (sig)
1721 pksignal(p, sig, ksi);
1722 ret = err;
1723 }
1724 else if (ret == ESRCH)
1725 ret = err;
1726 PROC_UNLOCK(p);
1727 }
1728 PGRP_UNLOCK(pgrp);
1729 }
1730 return (ret);
1731 }
1732
1733 #ifndef _SYS_SYSPROTO_H_
1734 struct kill_args {
1735 int pid;
1736 int signum;
1737 };
1738 #endif
1739 /* ARGSUSED */
1740 int
1741 sys_kill(struct thread *td, struct kill_args *uap)
1742 {
1743 ksiginfo_t ksi;
1744 struct proc *p;
1745 int error;
1746
1747 /*
1748 * A process in capability mode can send signals only to himself.
1749 * The main rationale behind this is that abort(3) is implemented as
1750 * kill(getpid(), SIGABRT).
1751 */
1752 if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid)
1753 return (ECAPMODE);
1754
1755 AUDIT_ARG_SIGNUM(uap->signum);
1756 AUDIT_ARG_PID(uap->pid);
1757 if ((u_int)uap->signum > _SIG_MAXSIG)
1758 return (EINVAL);
1759
1760 ksiginfo_init(&ksi);
1761 ksi.ksi_signo = uap->signum;
1762 ksi.ksi_code = SI_USER;
1763 ksi.ksi_pid = td->td_proc->p_pid;
1764 ksi.ksi_uid = td->td_ucred->cr_ruid;
1765
1766 if (uap->pid > 0) {
1767 /* kill single process */
1768 if ((p = pfind(uap->pid)) == NULL) {
1769 if ((p = zpfind(uap->pid)) == NULL)
1770 return (ESRCH);
1771 }
1772 AUDIT_ARG_PROCESS(p);
1773 error = p_cansignal(td, p, uap->signum);
1774 if (error == 0 && uap->signum)
1775 pksignal(p, uap->signum, &ksi);
1776 PROC_UNLOCK(p);
1777 return (error);
1778 }
1779 switch (uap->pid) {
1780 case -1: /* broadcast signal */
1781 return (killpg1(td, uap->signum, 0, 1, &ksi));
1782 case 0: /* signal own process group */
1783 return (killpg1(td, uap->signum, 0, 0, &ksi));
1784 default: /* negative explicit process group */
1785 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
1786 }
1787 /* NOTREACHED */
1788 }
1789
1790 int
1791 sys_pdkill(struct thread *td, struct pdkill_args *uap)
1792 {
1793 struct proc *p;
1794 cap_rights_t rights;
1795 int error;
1796
1797 AUDIT_ARG_SIGNUM(uap->signum);
1798 AUDIT_ARG_FD(uap->fd);
1799 if ((u_int)uap->signum > _SIG_MAXSIG)
1800 return (EINVAL);
1801
1802 error = procdesc_find(td, uap->fd,
1803 cap_rights_init(&rights, CAP_PDKILL), &p);
1804 if (error)
1805 return (error);
1806 AUDIT_ARG_PROCESS(p);
1807 error = p_cansignal(td, p, uap->signum);
1808 if (error == 0 && uap->signum)
1809 kern_psignal(p, uap->signum);
1810 PROC_UNLOCK(p);
1811 return (error);
1812 }
1813
1814 #if defined(COMPAT_43)
1815 #ifndef _SYS_SYSPROTO_H_
1816 struct okillpg_args {
1817 int pgid;
1818 int signum;
1819 };
1820 #endif
1821 /* ARGSUSED */
1822 int
1823 okillpg(struct thread *td, struct okillpg_args *uap)
1824 {
1825 ksiginfo_t ksi;
1826
1827 AUDIT_ARG_SIGNUM(uap->signum);
1828 AUDIT_ARG_PID(uap->pgid);
1829 if ((u_int)uap->signum > _SIG_MAXSIG)
1830 return (EINVAL);
1831
1832 ksiginfo_init(&ksi);
1833 ksi.ksi_signo = uap->signum;
1834 ksi.ksi_code = SI_USER;
1835 ksi.ksi_pid = td->td_proc->p_pid;
1836 ksi.ksi_uid = td->td_ucred->cr_ruid;
1837 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
1838 }
1839 #endif /* COMPAT_43 */
1840
1841 #ifndef _SYS_SYSPROTO_H_
1842 struct sigqueue_args {
1843 pid_t pid;
1844 int signum;
1845 /* union sigval */ void *value;
1846 };
1847 #endif
1848 int
1849 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
1850 {
1851 union sigval sv;
1852
1853 sv.sival_ptr = uap->value;
1854
1855 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
1856 }
1857
1858 int
1859 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
1860 {
1861 ksiginfo_t ksi;
1862 struct proc *p;
1863 int error;
1864
1865 if ((u_int)signum > _SIG_MAXSIG)
1866 return (EINVAL);
1867
1868 /*
1869 * Specification says sigqueue can only send signal to
1870 * single process.
1871 */
1872 if (pid <= 0)
1873 return (EINVAL);
1874
1875 if ((p = pfind(pid)) == NULL) {
1876 if ((p = zpfind(pid)) == NULL)
1877 return (ESRCH);
1878 }
1879 error = p_cansignal(td, p, signum);
1880 if (error == 0 && signum != 0) {
1881 ksiginfo_init(&ksi);
1882 ksi.ksi_flags = KSI_SIGQ;
1883 ksi.ksi_signo = signum;
1884 ksi.ksi_code = SI_QUEUE;
1885 ksi.ksi_pid = td->td_proc->p_pid;
1886 ksi.ksi_uid = td->td_ucred->cr_ruid;
1887 ksi.ksi_value = *value;
1888 error = pksignal(p, ksi.ksi_signo, &ksi);
1889 }
1890 PROC_UNLOCK(p);
1891 return (error);
1892 }
1893
1894 /*
1895 * Send a signal to a process group.
1896 */
1897 void
1898 gsignal(int pgid, int sig, ksiginfo_t *ksi)
1899 {
1900 struct pgrp *pgrp;
1901
1902 if (pgid != 0) {
1903 sx_slock(&proctree_lock);
1904 pgrp = pgfind(pgid);
1905 sx_sunlock(&proctree_lock);
1906 if (pgrp != NULL) {
1907 pgsignal(pgrp, sig, 0, ksi);
1908 PGRP_UNLOCK(pgrp);
1909 }
1910 }
1911 }
1912
1913 /*
1914 * Send a signal to a process group. If checktty is 1,
1915 * limit to members which have a controlling terminal.
1916 */
1917 void
1918 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
1919 {
1920 struct proc *p;
1921
1922 if (pgrp) {
1923 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
1924 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1925 PROC_LOCK(p);
1926 if (p->p_state == PRS_NORMAL &&
1927 (checkctty == 0 || p->p_flag & P_CONTROLT))
1928 pksignal(p, sig, ksi);
1929 PROC_UNLOCK(p);
1930 }
1931 }
1932 }
1933
1934
1935 /*
1936 * Recalculate the signal mask and reset the signal disposition after
1937 * usermode frame for delivery is formed. Should be called after
1938 * mach-specific routine, because sysent->sv_sendsig() needs correct
1939 * ps_siginfo and signal mask.
1940 */
1941 static void
1942 postsig_done(int sig, struct thread *td, struct sigacts *ps)
1943 {
1944 sigset_t mask;
1945
1946 mtx_assert(&ps->ps_mtx, MA_OWNED);
1947 td->td_ru.ru_nsignals++;
1948 mask = ps->ps_catchmask[_SIG_IDX(sig)];
1949 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1950 SIGADDSET(mask, sig);
1951 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
1952 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
1953 if (SIGISMEMBER(ps->ps_sigreset, sig))
1954 sigdflt(ps, sig);
1955 }
1956
1957
1958 /*
1959 * Send a signal caused by a trap to the current thread. If it will be
1960 * caught immediately, deliver it with correct code. Otherwise, post it
1961 * normally.
1962 */
1963 void
1964 trapsignal(struct thread *td, ksiginfo_t *ksi)
1965 {
1966 struct sigacts *ps;
1967 struct proc *p;
1968 int sig;
1969 int code;
1970
1971 p = td->td_proc;
1972 sig = ksi->ksi_signo;
1973 code = ksi->ksi_code;
1974 KASSERT(_SIG_VALID(sig), ("invalid signal"));
1975
1976 PROC_LOCK(p);
1977 ps = p->p_sigacts;
1978 mtx_lock(&ps->ps_mtx);
1979 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
1980 !SIGISMEMBER(td->td_sigmask, sig)) {
1981 #ifdef KTRACE
1982 if (KTRPOINT(curthread, KTR_PSIG))
1983 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
1984 &td->td_sigmask, code);
1985 #endif
1986 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
1987 ksi, &td->td_sigmask);
1988 postsig_done(sig, td, ps);
1989 mtx_unlock(&ps->ps_mtx);
1990 } else {
1991 /*
1992 * Avoid a possible infinite loop if the thread
1993 * masking the signal or process is ignoring the
1994 * signal.
1995 */
1996 if (kern_forcesigexit &&
1997 (SIGISMEMBER(td->td_sigmask, sig) ||
1998 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
1999 SIGDELSET(td->td_sigmask, sig);
2000 SIGDELSET(ps->ps_sigcatch, sig);
2001 SIGDELSET(ps->ps_sigignore, sig);
2002 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2003 }
2004 mtx_unlock(&ps->ps_mtx);
2005 p->p_code = code; /* XXX for core dump/debugger */
2006 p->p_sig = sig; /* XXX to verify code */
2007 tdsendsignal(p, td, sig, ksi);
2008 }
2009 PROC_UNLOCK(p);
2010 }
2011
2012 static struct thread *
2013 sigtd(struct proc *p, int sig, int prop)
2014 {
2015 struct thread *td, *signal_td;
2016
2017 PROC_LOCK_ASSERT(p, MA_OWNED);
2018
2019 /*
2020 * Check if current thread can handle the signal without
2021 * switching context to another thread.
2022 */
2023 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
2024 return (curthread);
2025 signal_td = NULL;
2026 FOREACH_THREAD_IN_PROC(p, td) {
2027 if (!SIGISMEMBER(td->td_sigmask, sig)) {
2028 signal_td = td;
2029 break;
2030 }
2031 }
2032 if (signal_td == NULL)
2033 signal_td = FIRST_THREAD_IN_PROC(p);
2034 return (signal_td);
2035 }
2036
2037 /*
2038 * Send the signal to the process. If the signal has an action, the action
2039 * is usually performed by the target process rather than the caller; we add
2040 * the signal to the set of pending signals for the process.
2041 *
2042 * Exceptions:
2043 * o When a stop signal is sent to a sleeping process that takes the
2044 * default action, the process is stopped without awakening it.
2045 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2046 * regardless of the signal action (eg, blocked or ignored).
2047 *
2048 * Other ignored signals are discarded immediately.
2049 *
2050 * NB: This function may be entered from the debugger via the "kill" DDB
2051 * command. There is little that can be done to mitigate the possibly messy
2052 * side effects of this unwise possibility.
2053 */
2054 void
2055 kern_psignal(struct proc *p, int sig)
2056 {
2057 ksiginfo_t ksi;
2058
2059 ksiginfo_init(&ksi);
2060 ksi.ksi_signo = sig;
2061 ksi.ksi_code = SI_KERNEL;
2062 (void) tdsendsignal(p, NULL, sig, &ksi);
2063 }
2064
2065 int
2066 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2067 {
2068
2069 return (tdsendsignal(p, NULL, sig, ksi));
2070 }
2071
2072 /* Utility function for finding a thread to send signal event to. */
2073 int
2074 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
2075 {
2076 struct thread *td;
2077
2078 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2079 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2080 if (td == NULL)
2081 return (ESRCH);
2082 *ttd = td;
2083 } else {
2084 *ttd = NULL;
2085 PROC_LOCK(p);
2086 }
2087 return (0);
2088 }
2089
2090 void
2091 tdsignal(struct thread *td, int sig)
2092 {
2093 ksiginfo_t ksi;
2094
2095 ksiginfo_init(&ksi);
2096 ksi.ksi_signo = sig;
2097 ksi.ksi_code = SI_KERNEL;
2098 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2099 }
2100
2101 void
2102 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2103 {
2104
2105 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2106 }
2107
2108 int
2109 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2110 {
2111 sig_t action;
2112 sigqueue_t *sigqueue;
2113 int prop;
2114 struct sigacts *ps;
2115 int intrval;
2116 int ret = 0;
2117 int wakeup_swapper;
2118
2119 MPASS(td == NULL || p == td->td_proc);
2120 PROC_LOCK_ASSERT(p, MA_OWNED);
2121
2122 if (!_SIG_VALID(sig))
2123 panic("%s(): invalid signal %d", __func__, sig);
2124
2125 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2126
2127 /*
2128 * IEEE Std 1003.1-2001: return success when killing a zombie.
2129 */
2130 if (p->p_state == PRS_ZOMBIE) {
2131 if (ksi && (ksi->ksi_flags & KSI_INS))
2132 ksiginfo_tryfree(ksi);
2133 return (ret);
2134 }
2135
2136 ps = p->p_sigacts;
2137 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
2138 prop = sigprop(sig);
2139
2140 if (td == NULL) {
2141 td = sigtd(p, sig, prop);
2142 sigqueue = &p->p_sigqueue;
2143 } else
2144 sigqueue = &td->td_sigqueue;
2145
2146 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2147
2148 /*
2149 * If the signal is being ignored,
2150 * then we forget about it immediately.
2151 * (Note: we don't set SIGCONT in ps_sigignore,
2152 * and if it is set to SIG_IGN,
2153 * action will be SIG_DFL here.)
2154 */
2155 mtx_lock(&ps->ps_mtx);
2156 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2157 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2158
2159 mtx_unlock(&ps->ps_mtx);
2160 if (ksi && (ksi->ksi_flags & KSI_INS))
2161 ksiginfo_tryfree(ksi);
2162 return (ret);
2163 }
2164 if (SIGISMEMBER(td->td_sigmask, sig))
2165 action = SIG_HOLD;
2166 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2167 action = SIG_CATCH;
2168 else
2169 action = SIG_DFL;
2170 if (SIGISMEMBER(ps->ps_sigintr, sig))
2171 intrval = EINTR;
2172 else
2173 intrval = ERESTART;
2174 mtx_unlock(&ps->ps_mtx);
2175
2176 if (prop & SA_CONT)
2177 sigqueue_delete_stopmask_proc(p);
2178 else if (prop & SA_STOP) {
2179 /*
2180 * If sending a tty stop signal to a member of an orphaned
2181 * process group, discard the signal here if the action
2182 * is default; don't stop the process below if sleeping,
2183 * and don't clear any pending SIGCONT.
2184 */
2185 if ((prop & SA_TTYSTOP) &&
2186 (p->p_pgrp->pg_jobc == 0) &&
2187 (action == SIG_DFL)) {
2188 if (ksi && (ksi->ksi_flags & KSI_INS))
2189 ksiginfo_tryfree(ksi);
2190 return (ret);
2191 }
2192 sigqueue_delete_proc(p, SIGCONT);
2193 if (p->p_flag & P_CONTINUED) {
2194 p->p_flag &= ~P_CONTINUED;
2195 PROC_LOCK(p->p_pptr);
2196 sigqueue_take(p->p_ksi);
2197 PROC_UNLOCK(p->p_pptr);
2198 }
2199 }
2200
2201 ret = sigqueue_add(sigqueue, sig, ksi);
2202 if (ret != 0)
2203 return (ret);
2204 signotify(td);
2205 /*
2206 * Defer further processing for signals which are held,
2207 * except that stopped processes must be continued by SIGCONT.
2208 */
2209 if (action == SIG_HOLD &&
2210 !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
2211 return (ret);
2212
2213 /* SIGKILL: Remove procfs STOPEVENTs. */
2214 if (sig == SIGKILL) {
2215 /* from procfs_ioctl.c: PIOCBIC */
2216 p->p_stops = 0;
2217 /* from procfs_ioctl.c: PIOCCONT */
2218 p->p_step = 0;
2219 wakeup(&p->p_step);
2220 }
2221 /*
2222 * Some signals have a process-wide effect and a per-thread
2223 * component. Most processing occurs when the process next
2224 * tries to cross the user boundary, however there are some
2225 * times when processing needs to be done immediately, such as
2226 * waking up threads so that they can cross the user boundary.
2227 * We try to do the per-process part here.
2228 */
2229 if (P_SHOULDSTOP(p)) {
2230 KASSERT(!(p->p_flag & P_WEXIT),
2231 ("signal to stopped but exiting process"));
2232 if (sig == SIGKILL) {
2233 /*
2234 * If traced process is already stopped,
2235 * then no further action is necessary.
2236 */
2237 if (p->p_flag & P_TRACED)
2238 goto out;
2239 /*
2240 * SIGKILL sets process running.
2241 * It will die elsewhere.
2242 * All threads must be restarted.
2243 */
2244 p->p_flag &= ~P_STOPPED_SIG;
2245 goto runfast;
2246 }
2247
2248 if (prop & SA_CONT) {
2249 /*
2250 * If traced process is already stopped,
2251 * then no further action is necessary.
2252 */
2253 if (p->p_flag & P_TRACED)
2254 goto out;
2255 /*
2256 * If SIGCONT is default (or ignored), we continue the
2257 * process but don't leave the signal in sigqueue as
2258 * it has no further action. If SIGCONT is held, we
2259 * continue the process and leave the signal in
2260 * sigqueue. If the process catches SIGCONT, let it
2261 * handle the signal itself. If it isn't waiting on
2262 * an event, it goes back to run state.
2263 * Otherwise, process goes back to sleep state.
2264 */
2265 p->p_flag &= ~P_STOPPED_SIG;
2266 PROC_SLOCK(p);
2267 if (p->p_numthreads == p->p_suspcount) {
2268 PROC_SUNLOCK(p);
2269 p->p_flag |= P_CONTINUED;
2270 p->p_xsig = SIGCONT;
2271 PROC_LOCK(p->p_pptr);
2272 childproc_continued(p);
2273 PROC_UNLOCK(p->p_pptr);
2274 PROC_SLOCK(p);
2275 }
2276 if (action == SIG_DFL) {
2277 thread_unsuspend(p);
2278 PROC_SUNLOCK(p);
2279 sigqueue_delete(sigqueue, sig);
2280 goto out;
2281 }
2282 if (action == SIG_CATCH) {
2283 /*
2284 * The process wants to catch it so it needs
2285 * to run at least one thread, but which one?
2286 */
2287 PROC_SUNLOCK(p);
2288 goto runfast;
2289 }
2290 /*
2291 * The signal is not ignored or caught.
2292 */
2293 thread_unsuspend(p);
2294 PROC_SUNLOCK(p);
2295 goto out;
2296 }
2297
2298 if (prop & SA_STOP) {
2299 /*
2300 * If traced process is already stopped,
2301 * then no further action is necessary.
2302 */
2303 if (p->p_flag & P_TRACED)
2304 goto out;
2305 /*
2306 * Already stopped, don't need to stop again
2307 * (If we did the shell could get confused).
2308 * Just make sure the signal STOP bit set.
2309 */
2310 p->p_flag |= P_STOPPED_SIG;
2311 sigqueue_delete(sigqueue, sig);
2312 goto out;
2313 }
2314
2315 /*
2316 * All other kinds of signals:
2317 * If a thread is sleeping interruptibly, simulate a
2318 * wakeup so that when it is continued it will be made
2319 * runnable and can look at the signal. However, don't make
2320 * the PROCESS runnable, leave it stopped.
2321 * It may run a bit until it hits a thread_suspend_check().
2322 */
2323 wakeup_swapper = 0;
2324 PROC_SLOCK(p);
2325 thread_lock(td);
2326 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
2327 wakeup_swapper = sleepq_abort(td, intrval);
2328 thread_unlock(td);
2329 PROC_SUNLOCK(p);
2330 if (wakeup_swapper)
2331 kick_proc0();
2332 goto out;
2333 /*
2334 * Mutexes are short lived. Threads waiting on them will
2335 * hit thread_suspend_check() soon.
2336 */
2337 } else if (p->p_state == PRS_NORMAL) {
2338 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2339 tdsigwakeup(td, sig, action, intrval);
2340 goto out;
2341 }
2342
2343 MPASS(action == SIG_DFL);
2344
2345 if (prop & SA_STOP) {
2346 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2347 goto out;
2348 p->p_flag |= P_STOPPED_SIG;
2349 p->p_xsig = sig;
2350 PROC_SLOCK(p);
2351 wakeup_swapper = sig_suspend_threads(td, p, 1);
2352 if (p->p_numthreads == p->p_suspcount) {
2353 /*
2354 * only thread sending signal to another
2355 * process can reach here, if thread is sending
2356 * signal to its process, because thread does
2357 * not suspend itself here, p_numthreads
2358 * should never be equal to p_suspcount.
2359 */
2360 thread_stopped(p);
2361 PROC_SUNLOCK(p);
2362 sigqueue_delete_proc(p, p->p_xsig);
2363 } else
2364 PROC_SUNLOCK(p);
2365 if (wakeup_swapper)
2366 kick_proc0();
2367 goto out;
2368 }
2369 } else {
2370 /* Not in "NORMAL" state. discard the signal. */
2371 sigqueue_delete(sigqueue, sig);
2372 goto out;
2373 }
2374
2375 /*
2376 * The process is not stopped so we need to apply the signal to all the
2377 * running threads.
2378 */
2379 runfast:
2380 tdsigwakeup(td, sig, action, intrval);
2381 PROC_SLOCK(p);
2382 thread_unsuspend(p);
2383 PROC_SUNLOCK(p);
2384 out:
2385 /* If we jump here, proc slock should not be owned. */
2386 PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
2387 return (ret);
2388 }
2389
2390 /*
2391 * The force of a signal has been directed against a single
2392 * thread. We need to see what we can do about knocking it
2393 * out of any sleep it may be in etc.
2394 */
2395 static void
2396 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2397 {
2398 struct proc *p = td->td_proc;
2399 int prop;
2400 int wakeup_swapper;
2401
2402 wakeup_swapper = 0;
2403 PROC_LOCK_ASSERT(p, MA_OWNED);
2404 prop = sigprop(sig);
2405
2406 PROC_SLOCK(p);
2407 thread_lock(td);
2408 /*
2409 * Bring the priority of a thread up if we want it to get
2410 * killed in this lifetime. Be careful to avoid bumping the
2411 * priority of the idle thread, since we still allow to signal
2412 * kernel processes.
2413 */
2414 if (action == SIG_DFL && (prop & SA_KILL) != 0 &&
2415 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2416 sched_prio(td, PUSER);
2417 if (TD_ON_SLEEPQ(td)) {
2418 /*
2419 * If thread is sleeping uninterruptibly
2420 * we can't interrupt the sleep... the signal will
2421 * be noticed when the process returns through
2422 * trap() or syscall().
2423 */
2424 if ((td->td_flags & TDF_SINTR) == 0)
2425 goto out;
2426 /*
2427 * If SIGCONT is default (or ignored) and process is
2428 * asleep, we are finished; the process should not
2429 * be awakened.
2430 */
2431 if ((prop & SA_CONT) && action == SIG_DFL) {
2432 thread_unlock(td);
2433 PROC_SUNLOCK(p);
2434 sigqueue_delete(&p->p_sigqueue, sig);
2435 /*
2436 * It may be on either list in this state.
2437 * Remove from both for now.
2438 */
2439 sigqueue_delete(&td->td_sigqueue, sig);
2440 return;
2441 }
2442
2443 /*
2444 * Don't awaken a sleeping thread for SIGSTOP if the
2445 * STOP signal is deferred.
2446 */
2447 if ((prop & SA_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2448 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2449 goto out;
2450
2451 /*
2452 * Give low priority threads a better chance to run.
2453 */
2454 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2455 sched_prio(td, PUSER);
2456
2457 wakeup_swapper = sleepq_abort(td, intrval);
2458 } else {
2459 /*
2460 * Other states do nothing with the signal immediately,
2461 * other than kicking ourselves if we are running.
2462 * It will either never be noticed, or noticed very soon.
2463 */
2464 #ifdef SMP
2465 if (TD_IS_RUNNING(td) && td != curthread)
2466 forward_signal(td);
2467 #endif
2468 }
2469 out:
2470 PROC_SUNLOCK(p);
2471 thread_unlock(td);
2472 if (wakeup_swapper)
2473 kick_proc0();
2474 }
2475
2476 static int
2477 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
2478 {
2479 struct thread *td2;
2480 int wakeup_swapper;
2481
2482 PROC_LOCK_ASSERT(p, MA_OWNED);
2483 PROC_SLOCK_ASSERT(p, MA_OWNED);
2484 MPASS(sending || td == curthread);
2485
2486 wakeup_swapper = 0;
2487 FOREACH_THREAD_IN_PROC(p, td2) {
2488 thread_lock(td2);
2489 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
2490 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
2491 (td2->td_flags & TDF_SINTR)) {
2492 if (td2->td_flags & TDF_SBDRY) {
2493 /*
2494 * Once a thread is asleep with
2495 * TDF_SBDRY and without TDF_SERESTART
2496 * or TDF_SEINTR set, it should never
2497 * become suspended due to this check.
2498 */
2499 KASSERT(!TD_IS_SUSPENDED(td2),
2500 ("thread with deferred stops suspended"));
2501 if (TD_SBDRY_INTR(td2))
2502 wakeup_swapper |= sleepq_abort(td2,
2503 TD_SBDRY_ERRNO(td2));
2504 } else if (!TD_IS_SUSPENDED(td2)) {
2505 thread_suspend_one(td2);
2506 }
2507 } else if (!TD_IS_SUSPENDED(td2)) {
2508 if (sending || td != td2)
2509 td2->td_flags |= TDF_ASTPENDING;
2510 #ifdef SMP
2511 if (TD_IS_RUNNING(td2) && td2 != td)
2512 forward_signal(td2);
2513 #endif
2514 }
2515 thread_unlock(td2);
2516 }
2517 return (wakeup_swapper);
2518 }
2519
2520 /*
2521 * Stop the process for an event deemed interesting to the debugger. If si is
2522 * non-NULL, this is a signal exchange; the new signal requested by the
2523 * debugger will be returned for handling. If si is NULL, this is some other
2524 * type of interesting event. The debugger may request a signal be delivered in
2525 * that case as well, however it will be deferred until it can be handled.
2526 */
2527 int
2528 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2529 {
2530 struct proc *p = td->td_proc;
2531 struct thread *td2;
2532 ksiginfo_t ksi;
2533 int prop;
2534
2535 PROC_LOCK_ASSERT(p, MA_OWNED);
2536 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2537 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2538 &p->p_mtx.lock_object, "Stopping for traced signal");
2539
2540 td->td_xsig = sig;
2541
2542 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2543 td->td_dbgflags |= TDB_XSIG;
2544 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2545 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2546 PROC_SLOCK(p);
2547 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2548 if (P_KILLED(p)) {
2549 /*
2550 * Ensure that, if we've been PT_KILLed, the
2551 * exit status reflects that. Another thread
2552 * may also be in ptracestop(), having just
2553 * received the SIGKILL, but this thread was
2554 * unsuspended first.
2555 */
2556 td->td_dbgflags &= ~TDB_XSIG;
2557 td->td_xsig = SIGKILL;
2558 p->p_ptevents = 0;
2559 break;
2560 }
2561 if (p->p_flag & P_SINGLE_EXIT &&
2562 !(td->td_dbgflags & TDB_EXIT)) {
2563 /*
2564 * Ignore ptrace stops except for thread exit
2565 * events when the process exits.
2566 */
2567 td->td_dbgflags &= ~TDB_XSIG;
2568 PROC_SUNLOCK(p);
2569 return (0);
2570 }
2571
2572 /*
2573 * Make wait(2) work. Ensure that right after the
2574 * attach, the thread which was decided to become the
2575 * leader of attach gets reported to the waiter.
2576 * Otherwise, just avoid overwriting another thread's
2577 * assignment to p_xthread. If another thread has
2578 * already set p_xthread, the current thread will get
2579 * a chance to report itself upon the next iteration.
2580 */
2581 if ((td->td_dbgflags & TDB_FSTP) != 0 ||
2582 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
2583 p->p_xthread == NULL)) {
2584 p->p_xsig = sig;
2585 p->p_xthread = td;
2586 td->td_dbgflags &= ~TDB_FSTP;
2587 p->p_flag2 &= ~P2_PTRACE_FSTP;
2588 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2589 sig_suspend_threads(td, p, 0);
2590 }
2591 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2592 td->td_dbgflags &= ~TDB_STOPATFORK;
2593 cv_broadcast(&p->p_dbgwait);
2594 }
2595 stopme:
2596 thread_suspend_switch(td, p);
2597 if (p->p_xthread == td)
2598 p->p_xthread = NULL;
2599 if (!(p->p_flag & P_TRACED))
2600 break;
2601 if (td->td_dbgflags & TDB_SUSPEND) {
2602 if (p->p_flag & P_SINGLE_EXIT)
2603 break;
2604 goto stopme;
2605 }
2606 }
2607 PROC_SUNLOCK(p);
2608 }
2609
2610 if (si != NULL && sig == td->td_xsig) {
2611 /* Parent wants us to take the original signal unchanged. */
2612 si->ksi_flags |= KSI_HEAD;
2613 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2614 si->ksi_signo = 0;
2615 } else if (td->td_xsig != 0) {
2616 /*
2617 * If parent wants us to take a new signal, then it will leave
2618 * it in td->td_xsig; otherwise we just look for signals again.
2619 */
2620 ksiginfo_init(&ksi);
2621 ksi.ksi_signo = td->td_xsig;
2622 ksi.ksi_flags |= KSI_PTRACE;
2623 prop = sigprop(td->td_xsig);
2624 td2 = sigtd(p, td->td_xsig, prop);
2625 tdsendsignal(p, td2, td->td_xsig, &ksi);
2626 if (td != td2)
2627 return (0);
2628 }
2629
2630 return (td->td_xsig);
2631 }
2632
2633 static void
2634 reschedule_signals(struct proc *p, sigset_t block, int flags)
2635 {
2636 struct sigacts *ps;
2637 struct thread *td;
2638 int sig;
2639
2640 PROC_LOCK_ASSERT(p, MA_OWNED);
2641 ps = p->p_sigacts;
2642 mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ?
2643 MA_OWNED : MA_NOTOWNED);
2644 if (SIGISEMPTY(p->p_siglist))
2645 return;
2646 SIGSETAND(block, p->p_siglist);
2647 while ((sig = sig_ffs(&block)) != 0) {
2648 SIGDELSET(block, sig);
2649 td = sigtd(p, sig, 0);
2650 signotify(td);
2651 if (!(flags & SIGPROCMASK_PS_LOCKED))
2652 mtx_lock(&ps->ps_mtx);
2653 if (p->p_flag & P_TRACED ||
2654 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
2655 !SIGISMEMBER(td->td_sigmask, sig)))
2656 tdsigwakeup(td, sig, SIG_CATCH,
2657 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
2658 ERESTART));
2659 if (!(flags & SIGPROCMASK_PS_LOCKED))
2660 mtx_unlock(&ps->ps_mtx);
2661 }
2662 }
2663
2664 void
2665 tdsigcleanup(struct thread *td)
2666 {
2667 struct proc *p;
2668 sigset_t unblocked;
2669
2670 p = td->td_proc;
2671 PROC_LOCK_ASSERT(p, MA_OWNED);
2672
2673 sigqueue_flush(&td->td_sigqueue);
2674 if (p->p_numthreads == 1)
2675 return;
2676
2677 /*
2678 * Since we cannot handle signals, notify signal post code
2679 * about this by filling the sigmask.
2680 *
2681 * Also, if needed, wake up thread(s) that do not block the
2682 * same signals as the exiting thread, since the thread might
2683 * have been selected for delivery and woken up.
2684 */
2685 SIGFILLSET(unblocked);
2686 SIGSETNAND(unblocked, td->td_sigmask);
2687 SIGFILLSET(td->td_sigmask);
2688 reschedule_signals(p, unblocked, 0);
2689
2690 }
2691
2692 static int
2693 sigdeferstop_curr_flags(int cflags)
2694 {
2695
2696 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
2697 (cflags & TDF_SBDRY) != 0);
2698 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
2699 }
2700
2701 /*
2702 * Defer the delivery of SIGSTOP for the current thread, according to
2703 * the requested mode. Returns previous flags, which must be restored
2704 * by sigallowstop().
2705 *
2706 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
2707 * cleared by the current thread, which allow the lock-less read-only
2708 * accesses below.
2709 */
2710 int
2711 sigdeferstop_impl(int mode)
2712 {
2713 struct thread *td;
2714 int cflags, nflags;
2715
2716 td = curthread;
2717 cflags = sigdeferstop_curr_flags(td->td_flags);
2718 switch (mode) {
2719 case SIGDEFERSTOP_NOP:
2720 nflags = cflags;
2721 break;
2722 case SIGDEFERSTOP_OFF:
2723 nflags = 0;
2724 break;
2725 case SIGDEFERSTOP_SILENT:
2726 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
2727 break;
2728 case SIGDEFERSTOP_EINTR:
2729 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
2730 break;
2731 case SIGDEFERSTOP_ERESTART:
2732 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
2733 break;
2734 default:
2735 panic("sigdeferstop: invalid mode %x", mode);
2736 break;
2737 }
2738 if (cflags == nflags)
2739 return (SIGDEFERSTOP_VAL_NCHG);
2740 thread_lock(td);
2741 td->td_flags = (td->td_flags & ~cflags) | nflags;
2742 thread_unlock(td);
2743 return (cflags);
2744 }
2745
2746 /*
2747 * Restores the STOP handling mode, typically permitting the delivery
2748 * of SIGSTOP for the current thread. This does not immediately
2749 * suspend if a stop was posted. Instead, the thread will suspend
2750 * either via ast() or a subsequent interruptible sleep.
2751 */
2752 void
2753 sigallowstop_impl(int prev)
2754 {
2755 struct thread *td;
2756 int cflags;
2757
2758 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
2759 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
2760 ("sigallowstop: incorrect previous mode %x", prev));
2761 td = curthread;
2762 cflags = sigdeferstop_curr_flags(td->td_flags);
2763 if (cflags != prev) {
2764 thread_lock(td);
2765 td->td_flags = (td->td_flags & ~cflags) | prev;
2766 thread_unlock(td);
2767 }
2768 }
2769
2770 /*
2771 * If the current process has received a signal (should be caught or cause
2772 * termination, should interrupt current syscall), return the signal number.
2773 * Stop signals with default action are processed immediately, then cleared;
2774 * they aren't returned. This is checked after each entry to the system for
2775 * a syscall or trap (though this can usually be done without calling issignal
2776 * by checking the pending signal masks in cursig.) The normal call
2777 * sequence is
2778 *
2779 * while (sig = cursig(curthread))
2780 * postsig(sig);
2781 */
2782 static int
2783 issignal(struct thread *td)
2784 {
2785 struct proc *p;
2786 struct sigacts *ps;
2787 struct sigqueue *queue;
2788 sigset_t sigpending;
2789 int prop, sig, traced;
2790 ksiginfo_t ksi;
2791
2792 p = td->td_proc;
2793 ps = p->p_sigacts;
2794 mtx_assert(&ps->ps_mtx, MA_OWNED);
2795 PROC_LOCK_ASSERT(p, MA_OWNED);
2796 for (;;) {
2797 traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
2798
2799 sigpending = td->td_sigqueue.sq_signals;
2800 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
2801 SIGSETNAND(sigpending, td->td_sigmask);
2802
2803 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
2804 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2805 SIG_STOPSIGMASK(sigpending);
2806 if (SIGISEMPTY(sigpending)) /* no signal to send */
2807 return (0);
2808 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
2809 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
2810 SIGISMEMBER(sigpending, SIGSTOP)) {
2811 /*
2812 * If debugger just attached, always consume
2813 * SIGSTOP from ptrace(PT_ATTACH) first, to
2814 * execute the debugger attach ritual in
2815 * order.
2816 */
2817 sig = SIGSTOP;
2818 td->td_dbgflags |= TDB_FSTP;
2819 } else {
2820 sig = sig_ffs(&sigpending);
2821 }
2822
2823 if (p->p_stops & S_SIG) {
2824 mtx_unlock(&ps->ps_mtx);
2825 stopevent(p, S_SIG, sig);
2826 mtx_lock(&ps->ps_mtx);
2827 }
2828
2829 /*
2830 * We should see pending but ignored signals
2831 * only if P_TRACED was on when they were posted.
2832 */
2833 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
2834 sigqueue_delete(&td->td_sigqueue, sig);
2835 sigqueue_delete(&p->p_sigqueue, sig);
2836 continue;
2837 }
2838 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
2839 /*
2840 * If traced, always stop.
2841 * Remove old signal from queue before the stop.
2842 * XXX shrug off debugger, it causes siginfo to
2843 * be thrown away.
2844 */
2845 queue = &td->td_sigqueue;
2846 ksiginfo_init(&ksi);
2847 if (sigqueue_get(queue, sig, &ksi) == 0) {
2848 queue = &p->p_sigqueue;
2849 sigqueue_get(queue, sig, &ksi);
2850 }
2851 td->td_si = ksi.ksi_info;
2852
2853 mtx_unlock(&ps->ps_mtx);
2854 sig = ptracestop(td, sig, &ksi);
2855 mtx_lock(&ps->ps_mtx);
2856
2857 /*
2858 * Keep looking if the debugger discarded or
2859 * replaced the signal.
2860 */
2861 if (sig == 0)
2862 continue;
2863
2864 /*
2865 * If the signal became masked, re-queue it.
2866 */
2867 if (SIGISMEMBER(td->td_sigmask, sig)) {
2868 ksi.ksi_flags |= KSI_HEAD;
2869 sigqueue_add(&p->p_sigqueue, sig, &ksi);
2870 continue;
2871 }
2872
2873 /*
2874 * If the traced bit got turned off, requeue
2875 * the signal and go back up to the top to
2876 * rescan signals. This ensures that p_sig*
2877 * and p_sigact are consistent.
2878 */
2879 if ((p->p_flag & P_TRACED) == 0) {
2880 ksi.ksi_flags |= KSI_HEAD;
2881 sigqueue_add(queue, sig, &ksi);
2882 continue;
2883 }
2884 }
2885
2886 prop = sigprop(sig);
2887
2888 /*
2889 * Decide whether the signal should be returned.
2890 * Return the signal's number, or fall through
2891 * to clear it from the pending mask.
2892 */
2893 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2894
2895 case (intptr_t)SIG_DFL:
2896 /*
2897 * Don't take default actions on system processes.
2898 */
2899 if (p->p_pid <= 1) {
2900 #ifdef DIAGNOSTIC
2901 /*
2902 * Are you sure you want to ignore SIGSEGV
2903 * in init? XXX
2904 */
2905 printf("Process (pid %lu) got signal %d\n",
2906 (u_long)p->p_pid, sig);
2907 #endif
2908 break; /* == ignore */
2909 }
2910 /*
2911 * If there is a pending stop signal to process with
2912 * default action, stop here, then clear the signal.
2913 * Traced or exiting processes should ignore stops.
2914 * Additionally, a member of an orphaned process group
2915 * should ignore tty stops.
2916 */
2917 if (prop & SA_STOP) {
2918 if (p->p_flag &
2919 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) ||
2920 (p->p_pgrp->pg_jobc == 0 &&
2921 prop & SA_TTYSTOP))
2922 break; /* == ignore */
2923 if (TD_SBDRY_INTR(td)) {
2924 KASSERT((td->td_flags & TDF_SBDRY) != 0,
2925 ("lost TDF_SBDRY"));
2926 return (-1);
2927 }
2928 mtx_unlock(&ps->ps_mtx);
2929 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2930 &p->p_mtx.lock_object, "Catching SIGSTOP");
2931 sigqueue_delete(&td->td_sigqueue, sig);
2932 sigqueue_delete(&p->p_sigqueue, sig);
2933 p->p_flag |= P_STOPPED_SIG;
2934 p->p_xsig = sig;
2935 PROC_SLOCK(p);
2936 sig_suspend_threads(td, p, 0);
2937 thread_suspend_switch(td, p);
2938 PROC_SUNLOCK(p);
2939 mtx_lock(&ps->ps_mtx);
2940 goto next;
2941 } else if (prop & SA_IGNORE) {
2942 /*
2943 * Except for SIGCONT, shouldn't get here.
2944 * Default action is to ignore; drop it.
2945 */
2946 break; /* == ignore */
2947 } else
2948 return (sig);
2949 /*NOTREACHED*/
2950
2951 case (intptr_t)SIG_IGN:
2952 /*
2953 * Masking above should prevent us ever trying
2954 * to take action on an ignored signal other
2955 * than SIGCONT, unless process is traced.
2956 */
2957 if ((prop & SA_CONT) == 0 &&
2958 (p->p_flag & P_TRACED) == 0)
2959 printf("issignal\n");
2960 break; /* == ignore */
2961
2962 default:
2963 /*
2964 * This signal has an action, let
2965 * postsig() process it.
2966 */
2967 return (sig);
2968 }
2969 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
2970 sigqueue_delete(&p->p_sigqueue, sig);
2971 next:;
2972 }
2973 /* NOTREACHED */
2974 }
2975
2976 void
2977 thread_stopped(struct proc *p)
2978 {
2979 int n;
2980
2981 PROC_LOCK_ASSERT(p, MA_OWNED);
2982 PROC_SLOCK_ASSERT(p, MA_OWNED);
2983 n = p->p_suspcount;
2984 if (p == curproc)
2985 n++;
2986 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
2987 PROC_SUNLOCK(p);
2988 p->p_flag &= ~P_WAITED;
2989 PROC_LOCK(p->p_pptr);
2990 childproc_stopped(p, (p->p_flag & P_TRACED) ?
2991 CLD_TRAPPED : CLD_STOPPED);
2992 PROC_UNLOCK(p->p_pptr);
2993 PROC_SLOCK(p);
2994 }
2995 }
2996
2997 /*
2998 * Take the action for the specified signal
2999 * from the current set of pending signals.
3000 */
3001 int
3002 postsig(int sig)
3003 {
3004 struct thread *td;
3005 struct proc *p;
3006 struct sigacts *ps;
3007 sig_t action;
3008 ksiginfo_t ksi;
3009 sigset_t returnmask;
3010
3011 KASSERT(sig != 0, ("postsig"));
3012
3013 td = curthread;
3014 p = td->td_proc;
3015 PROC_LOCK_ASSERT(p, MA_OWNED);
3016 ps = p->p_sigacts;
3017 mtx_assert(&ps->ps_mtx, MA_OWNED);
3018 ksiginfo_init(&ksi);
3019 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3020 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3021 return (0);
3022 ksi.ksi_signo = sig;
3023 if (ksi.ksi_code == SI_TIMER)
3024 itimer_accept(p, ksi.ksi_timerid, &ksi);
3025 action = ps->ps_sigact[_SIG_IDX(sig)];
3026 #ifdef KTRACE
3027 if (KTRPOINT(td, KTR_PSIG))
3028 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3029 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3030 #endif
3031 if ((p->p_stops & S_SIG) != 0) {
3032 mtx_unlock(&ps->ps_mtx);
3033 stopevent(p, S_SIG, sig);
3034 mtx_lock(&ps->ps_mtx);
3035 }
3036
3037 if (action == SIG_DFL) {
3038 /*
3039 * Default action, where the default is to kill
3040 * the process. (Other cases were ignored above.)
3041 */
3042 mtx_unlock(&ps->ps_mtx);
3043 proc_td_siginfo_capture(td, &ksi.ksi_info);
3044 sigexit(td, sig);
3045 /* NOTREACHED */
3046 } else {
3047 /*
3048 * If we get here, the signal must be caught.
3049 */
3050 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3051 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3052 ("postsig action: blocked sig %d", sig));
3053
3054 /*
3055 * Set the new mask value and also defer further
3056 * occurrences of this signal.
3057 *
3058 * Special case: user has done a sigsuspend. Here the
3059 * current mask is not of interest, but rather the
3060 * mask from before the sigsuspend is what we want
3061 * restored after the signal processing is completed.
3062 */
3063 if (td->td_pflags & TDP_OLDMASK) {
3064 returnmask = td->td_oldsigmask;
3065 td->td_pflags &= ~TDP_OLDMASK;
3066 } else
3067 returnmask = td->td_sigmask;
3068
3069 if (p->p_sig == sig) {
3070 p->p_code = 0;
3071 p->p_sig = 0;
3072 }
3073 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3074 postsig_done(sig, td, ps);
3075 }
3076 return (1);
3077 }
3078
3079 /*
3080 * Kill the current process for stated reason.
3081 */
3082 void
3083 killproc(struct proc *p, char *why)
3084 {
3085
3086 PROC_LOCK_ASSERT(p, MA_OWNED);
3087 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3088 p->p_comm);
3089 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid,
3090 p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why);
3091 p->p_flag |= P_WKILLED;
3092 kern_psignal(p, SIGKILL);
3093 }
3094
3095 /*
3096 * Force the current process to exit with the specified signal, dumping core
3097 * if appropriate. We bypass the normal tests for masked and caught signals,
3098 * allowing unrecoverable failures to terminate the process without changing
3099 * signal state. Mark the accounting record with the signal termination.
3100 * If dumping core, save the signal number for the debugger. Calls exit and
3101 * does not return.
3102 */
3103 void
3104 sigexit(struct thread *td, int sig)
3105 {
3106 struct proc *p = td->td_proc;
3107
3108 PROC_LOCK_ASSERT(p, MA_OWNED);
3109 p->p_acflag |= AXSIG;
3110 /*
3111 * We must be single-threading to generate a core dump. This
3112 * ensures that the registers in the core file are up-to-date.
3113 * Also, the ELF dump handler assumes that the thread list doesn't
3114 * change out from under it.
3115 *
3116 * XXX If another thread attempts to single-thread before us
3117 * (e.g. via fork()), we won't get a dump at all.
3118 */
3119 if ((sigprop(sig) & SA_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) {
3120 p->p_sig = sig;
3121 /*
3122 * Log signals which would cause core dumps
3123 * (Log as LOG_INFO to appease those who don't want
3124 * these messages.)
3125 * XXX : Todo, as well as euid, write out ruid too
3126 * Note that coredump() drops proc lock.
3127 */
3128 if (coredump(td) == 0)
3129 sig |= WCOREFLAG;
3130 if (kern_logsigexit)
3131 log(LOG_INFO,
3132 "pid %d (%s), uid %d: exited on signal %d%s\n",
3133 p->p_pid, p->p_comm,
3134 td->td_ucred ? td->td_ucred->cr_uid : -1,
3135 sig &~ WCOREFLAG,
3136 sig & WCOREFLAG ? " (core dumped)" : "");
3137 } else
3138 PROC_UNLOCK(p);
3139 exit1(td, 0, sig);
3140 /* NOTREACHED */
3141 }
3142
3143 /*
3144 * Send queued SIGCHLD to parent when child process's state
3145 * is changed.
3146 */
3147 static void
3148 sigparent(struct proc *p, int reason, int status)
3149 {
3150 PROC_LOCK_ASSERT(p, MA_OWNED);
3151 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3152
3153 if (p->p_ksi != NULL) {
3154 p->p_ksi->ksi_signo = SIGCHLD;
3155 p->p_ksi->ksi_code = reason;
3156 p->p_ksi->ksi_status = status;
3157 p->p_ksi->ksi_pid = p->p_pid;
3158 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3159 if (KSI_ONQ(p->p_ksi))
3160 return;
3161 }
3162 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3163 }
3164
3165 static void
3166 childproc_jobstate(struct proc *p, int reason, int sig)
3167 {
3168 struct sigacts *ps;
3169
3170 PROC_LOCK_ASSERT(p, MA_OWNED);
3171 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3172
3173 /*
3174 * Wake up parent sleeping in kern_wait(), also send
3175 * SIGCHLD to parent, but SIGCHLD does not guarantee
3176 * that parent will awake, because parent may masked
3177 * the signal.
3178 */
3179 p->p_pptr->p_flag |= P_STATCHILD;
3180 wakeup(p->p_pptr);
3181
3182 ps = p->p_pptr->p_sigacts;
3183 mtx_lock(&ps->ps_mtx);
3184 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3185 mtx_unlock(&ps->ps_mtx);
3186 sigparent(p, reason, sig);
3187 } else
3188 mtx_unlock(&ps->ps_mtx);
3189 }
3190
3191 void
3192 childproc_stopped(struct proc *p, int reason)
3193 {
3194
3195 childproc_jobstate(p, reason, p->p_xsig);
3196 }
3197
3198 void
3199 childproc_continued(struct proc *p)
3200 {
3201 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3202 }
3203
3204 void
3205 childproc_exited(struct proc *p)
3206 {
3207 int reason, status;
3208
3209 if (WCOREDUMP(p->p_xsig)) {
3210 reason = CLD_DUMPED;
3211 status = WTERMSIG(p->p_xsig);
3212 } else if (WIFSIGNALED(p->p_xsig)) {
3213 reason = CLD_KILLED;
3214 status = WTERMSIG(p->p_xsig);
3215 } else {
3216 reason = CLD_EXITED;
3217 status = p->p_xexit;
3218 }
3219 /*
3220 * XXX avoid calling wakeup(p->p_pptr), the work is
3221 * done in exit1().
3222 */
3223 sigparent(p, reason, status);
3224 }
3225
3226 /*
3227 * We only have 1 character for the core count in the format
3228 * string, so the range will be 0-9
3229 */
3230 #define MAX_NUM_CORES 10
3231 static int num_cores = 5;
3232
3233 static int
3234 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3235 {
3236 int error;
3237 int new_val;
3238
3239 new_val = num_cores;
3240 error = sysctl_handle_int(oidp, &new_val, 0, req);
3241 if (error != 0 || req->newptr == NULL)
3242 return (error);
3243 if (new_val > MAX_NUM_CORES)
3244 new_val = MAX_NUM_CORES;
3245 if (new_val < 0)
3246 new_val = 0;
3247 num_cores = new_val;
3248 return (0);
3249 }
3250 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
3251 0, sizeof(int), sysctl_debug_num_cores_check, "I", "");
3252
3253 #define GZ_SUFFIX ".gz"
3254
3255 #ifdef GZIO
3256 static int compress_user_cores = 1;
3257 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RWTUN,
3258 &compress_user_cores, 0, "Compression of user corefiles");
3259
3260 int compress_user_cores_gzlevel = 6;
3261 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RWTUN,
3262 &compress_user_cores_gzlevel, 0, "Corefile gzip compression level");
3263 #else
3264 static int compress_user_cores = 0;
3265 #endif
3266
3267 /*
3268 * Protect the access to corefilename[] by allproc_lock.
3269 */
3270 #define corefilename_lock allproc_lock
3271
3272 static char corefilename[MAXPATHLEN] = {"%N.core"};
3273 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3274
3275 static int
3276 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
3277 {
3278 int error;
3279
3280 sx_xlock(&corefilename_lock);
3281 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
3282 req);
3283 sx_xunlock(&corefilename_lock);
3284
3285 return (error);
3286 }
3287 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
3288 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
3289 "Process corefile name format string");
3290
3291 /*
3292 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3293 * Expand the name described in corefilename, using name, uid, and pid
3294 * and open/create core file.
3295 * corefilename is a printf-like string, with three format specifiers:
3296 * %N name of process ("name")
3297 * %P process id (pid)
3298 * %U user id (uid)
3299 * For example, "%N.core" is the default; they can be disabled completely
3300 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3301 * This is controlled by the sysctl variable kern.corefile (see above).
3302 */
3303 static int
3304 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
3305 int compress, struct vnode **vpp, char **namep)
3306 {
3307 struct nameidata nd;
3308 struct sbuf sb;
3309 const char *format;
3310 char *hostname, *name;
3311 int indexpos, i, error, cmode, flags, oflags;
3312
3313 hostname = NULL;
3314 format = corefilename;
3315 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
3316 indexpos = -1;
3317 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
3318 sx_slock(&corefilename_lock);
3319 for (i = 0; format[i] != '\0'; i++) {
3320 switch (format[i]) {
3321 case '%': /* Format character */
3322 i++;
3323 switch (format[i]) {
3324 case '%':
3325 sbuf_putc(&sb, '%');
3326 break;
3327 case 'H': /* hostname */
3328 if (hostname == NULL) {
3329 hostname = malloc(MAXHOSTNAMELEN,
3330 M_TEMP, M_WAITOK);
3331 }
3332 getcredhostname(td->td_ucred, hostname,
3333 MAXHOSTNAMELEN);
3334 sbuf_printf(&sb, "%s", hostname);
3335 break;
3336 case 'I': /* autoincrementing index */
3337 sbuf_printf(&sb, "");
3338 indexpos = sbuf_len(&sb) - 1;
3339 break;
3340 case 'N': /* process name */
3341 sbuf_printf(&sb, "%s", comm);
3342 break;
3343 case 'P': /* process id */
3344 sbuf_printf(&sb, "%u", pid);
3345 break;
3346 case 'U': /* user id */
3347 sbuf_printf(&sb, "%u", uid);
3348 break;
3349 default:
3350 log(LOG_ERR,
3351 "Unknown format character %c in "
3352 "corename `%s'\n", format[i], format);
3353 break;
3354 }
3355 break;
3356 default:
3357 sbuf_putc(&sb, format[i]);
3358 break;
3359 }
3360 }
3361 sx_sunlock(&corefilename_lock);
3362 free(hostname, M_TEMP);
3363 if (compress)
3364 sbuf_printf(&sb, GZ_SUFFIX);
3365 if (sbuf_error(&sb) != 0) {
3366 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
3367 "long\n", (long)pid, comm, (u_long)uid);
3368 sbuf_delete(&sb);
3369 free(name, M_TEMP);
3370 return (ENOMEM);
3371 }
3372 sbuf_finish(&sb);
3373 sbuf_delete(&sb);
3374
3375 cmode = S_IRUSR | S_IWUSR;
3376 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3377 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3378
3379 /*
3380 * If the core format has a %I in it, then we need to check
3381 * for existing corefiles before returning a name.
3382 * To do this we iterate over 0..num_cores to find a
3383 * non-existing core file name to use.
3384 */
3385 if (indexpos != -1) {
3386 for (i = 0; i < num_cores; i++) {
3387 flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW;
3388 name[indexpos] = '' + i;
3389 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3390 error = vn_open_cred(&nd, &flags, cmode, oflags,
3391 td->td_ucred, NULL);
3392 if (error) {
3393 if (error == EEXIST)
3394 continue;
3395 log(LOG_ERR,
3396 "pid %d (%s), uid (%u): Path `%s' failed "
3397 "on initial open test, error = %d\n",
3398 pid, comm, uid, name, error);
3399 }
3400 goto out;
3401 }
3402 }
3403
3404 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3405 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3406 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL);
3407 out:
3408 if (error) {
3409 #ifdef AUDIT
3410 audit_proc_coredump(td, name, error);
3411 #endif
3412 free(name, M_TEMP);
3413 return (error);
3414 }
3415 NDFREE(&nd, NDF_ONLY_PNBUF);
3416 *vpp = nd.ni_vp;
3417 *namep = name;
3418 return (0);
3419 }
3420
3421 static int
3422 coredump_sanitise_path(const char *path)
3423 {
3424 size_t i;
3425
3426 /*
3427 * Only send a subset of ASCII to devd(8) because it
3428 * might pass these strings to sh -c.
3429 */
3430 for (i = 0; path[i]; i++)
3431 if (!(isalpha(path[i]) || isdigit(path[i])) &&
3432 path[i] != '/' && path[i] != '.' &&
3433 path[i] != '-')
3434 return (0);
3435
3436 return (1);
3437 }
3438
3439 /*
3440 * Dump a process' core. The main routine does some
3441 * policy checking, and creates the name of the coredump;
3442 * then it passes on a vnode and a size limit to the process-specific
3443 * coredump routine if there is one; if there _is not_ one, it returns
3444 * ENOSYS; otherwise it returns the error from the process-specific routine.
3445 */
3446
3447 static int
3448 coredump(struct thread *td)
3449 {
3450 struct proc *p = td->td_proc;
3451 struct ucred *cred = td->td_ucred;
3452 struct vnode *vp;
3453 struct flock lf;
3454 struct vattr vattr;
3455 int error, error1, locked;
3456 char *name; /* name of corefile */
3457 void *rl_cookie;
3458 off_t limit;
3459 char *data = NULL;
3460 char *fullpath, *freepath = NULL;
3461 size_t len;
3462 static const char comm_name[] = "comm=";
3463 static const char core_name[] = "core=";
3464
3465 PROC_LOCK_ASSERT(p, MA_OWNED);
3466 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
3467 _STOPEVENT(p, S_CORE, 0);
3468
3469 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
3470 (p->p_flag2 & P2_NOTRACE) != 0) {
3471 PROC_UNLOCK(p);
3472 return (EFAULT);
3473 }
3474
3475 /*
3476 * Note that the bulk of limit checking is done after
3477 * the corefile is created. The exception is if the limit
3478 * for corefiles is 0, in which case we don't bother
3479 * creating the corefile at all. This layout means that
3480 * a corefile is truncated instead of not being created,
3481 * if it is larger than the limit.
3482 */
3483 limit = (off_t)lim_cur(td, RLIMIT_CORE);
3484 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
3485 PROC_UNLOCK(p);
3486 return (EFBIG);
3487 }
3488 PROC_UNLOCK(p);
3489
3490 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
3491 compress_user_cores, &vp, &name);
3492 if (error != 0)
3493 return (error);
3494
3495 /*
3496 * Don't dump to non-regular files or files with links.
3497 * Do not dump into system files.
3498 */
3499 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
3500 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0) {
3501 VOP_UNLOCK(vp, 0);
3502 error = EFAULT;
3503 goto out;
3504 }
3505
3506 VOP_UNLOCK(vp, 0);
3507
3508 /* Postpone other writers, including core dumps of other processes. */
3509 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
3510
3511 lf.l_whence = SEEK_SET;
3512 lf.l_start = 0;
3513 lf.l_len = 0;
3514 lf.l_type = F_WRLCK;
3515 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
3516
3517 VATTR_NULL(&vattr);
3518 vattr.va_size = 0;
3519 if (set_core_nodump_flag)
3520 vattr.va_flags = UF_NODUMP;
3521 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3522 VOP_SETATTR(vp, &vattr, cred);
3523 VOP_UNLOCK(vp, 0);
3524 PROC_LOCK(p);
3525 p->p_acflag |= ACORE;
3526 PROC_UNLOCK(p);
3527
3528 if (p->p_sysent->sv_coredump != NULL) {
3529 error = p->p_sysent->sv_coredump(td, vp, limit,
3530 compress_user_cores ? IMGACT_CORE_COMPRESS : 0);
3531 } else {
3532 error = ENOSYS;
3533 }
3534
3535 if (locked) {
3536 lf.l_type = F_UNLCK;
3537 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3538 }
3539 vn_rangelock_unlock(vp, rl_cookie);
3540
3541 /*
3542 * Notify the userland helper that a process triggered a core dump.
3543 * This allows the helper to run an automated debugging session.
3544 */
3545 if (error != 0 || coredump_devctl == 0)
3546 goto out;
3547 len = MAXPATHLEN * 2 + sizeof(comm_name) - 1 +
3548 sizeof(' ') + sizeof(core_name) - 1;
3549 data = malloc(len, M_TEMP, M_WAITOK);
3550 if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
3551 goto out;
3552 if (!coredump_sanitise_path(fullpath))
3553 goto out;
3554 snprintf(data, len, "%s%s ", comm_name, fullpath);
3555 free(freepath, M_TEMP);
3556 freepath = NULL;
3557 if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
3558 goto out;
3559 if (!coredump_sanitise_path(fullpath))
3560 goto out;
3561 strlcat(data, core_name, len);
3562 strlcat(data, fullpath, len);
3563 devctl_notify("kernel", "signal", "coredump", data);
3564 out:
3565 error1 = vn_close(vp, FWRITE, cred, td);
3566 if (error == 0)
3567 error = error1;
3568 #ifdef AUDIT
3569 audit_proc_coredump(td, name, error);
3570 #endif
3571 free(freepath, M_TEMP);
3572 free(data, M_TEMP);
3573 free(name, M_TEMP);
3574 return (error);
3575 }
3576
3577 /*
3578 * Nonexistent system call-- signal process (may want to handle it). Flag
3579 * error in case process won't see signal immediately (blocked or ignored).
3580 */
3581 #ifndef _SYS_SYSPROTO_H_
3582 struct nosys_args {
3583 int dummy;
3584 };
3585 #endif
3586 /* ARGSUSED */
3587 int
3588 nosys(struct thread *td, struct nosys_args *args)
3589 {
3590 struct proc *p;
3591
3592 p = td->td_proc;
3593
3594 PROC_LOCK(p);
3595 tdsignal(td, SIGSYS);
3596 PROC_UNLOCK(p);
3597 if (kern_lognosys == 1 || kern_lognosys == 3) {
3598 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3599 td->td_sa.code);
3600 }
3601 if (kern_lognosys == 2 || kern_lognosys == 3) {
3602 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3603 td->td_sa.code);
3604 }
3605 return (ENOSYS);
3606 }
3607
3608 /*
3609 * Send a SIGIO or SIGURG signal to a process or process group using stored
3610 * credentials rather than those of the current process.
3611 */
3612 void
3613 pgsigio(struct sigio **sigiop, int sig, int checkctty)
3614 {
3615 ksiginfo_t ksi;
3616 struct sigio *sigio;
3617
3618 ksiginfo_init(&ksi);
3619 ksi.ksi_signo = sig;
3620 ksi.ksi_code = SI_KERNEL;
3621
3622 SIGIO_LOCK();
3623 sigio = *sigiop;
3624 if (sigio == NULL) {
3625 SIGIO_UNLOCK();
3626 return;
3627 }
3628 if (sigio->sio_pgid > 0) {
3629 PROC_LOCK(sigio->sio_proc);
3630 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3631 kern_psignal(sigio->sio_proc, sig);
3632 PROC_UNLOCK(sigio->sio_proc);
3633 } else if (sigio->sio_pgid < 0) {
3634 struct proc *p;
3635
3636 PGRP_LOCK(sigio->sio_pgrp);
3637 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3638 PROC_LOCK(p);
3639 if (p->p_state == PRS_NORMAL &&
3640 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3641 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3642 kern_psignal(p, sig);
3643 PROC_UNLOCK(p);
3644 }
3645 PGRP_UNLOCK(sigio->sio_pgrp);
3646 }
3647 SIGIO_UNLOCK();
3648 }
3649
3650 static int
3651 filt_sigattach(struct knote *kn)
3652 {
3653 struct proc *p = curproc;
3654
3655 kn->kn_ptr.p_proc = p;
3656 kn->kn_flags |= EV_CLEAR; /* automatically set */
3657
3658 knlist_add(p->p_klist, kn, 0);
3659
3660 return (0);
3661 }
3662
3663 static void
3664 filt_sigdetach(struct knote *kn)
3665 {
3666 struct proc *p = kn->kn_ptr.p_proc;
3667
3668 knlist_remove(p->p_klist, kn, 0);
3669 }
3670
3671 /*
3672 * signal knotes are shared with proc knotes, so we apply a mask to
3673 * the hint in order to differentiate them from process hints. This
3674 * could be avoided by using a signal-specific knote list, but probably
3675 * isn't worth the trouble.
3676 */
3677 static int
3678 filt_signal(struct knote *kn, long hint)
3679 {
3680
3681 if (hint & NOTE_SIGNAL) {
3682 hint &= ~NOTE_SIGNAL;
3683
3684 if (kn->kn_id == hint)
3685 kn->kn_data++;
3686 }
3687 return (kn->kn_data != 0);
3688 }
3689
3690 struct sigacts *
3691 sigacts_alloc(void)
3692 {
3693 struct sigacts *ps;
3694
3695 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3696 refcount_init(&ps->ps_refcnt, 1);
3697 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3698 return (ps);
3699 }
3700
3701 void
3702 sigacts_free(struct sigacts *ps)
3703 {
3704
3705 if (refcount_release(&ps->ps_refcnt) == 0)
3706 return;
3707 mtx_destroy(&ps->ps_mtx);
3708 free(ps, M_SUBPROC);
3709 }
3710
3711 struct sigacts *
3712 sigacts_hold(struct sigacts *ps)
3713 {
3714
3715 refcount_acquire(&ps->ps_refcnt);
3716 return (ps);
3717 }
3718
3719 void
3720 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3721 {
3722
3723 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3724 mtx_lock(&src->ps_mtx);
3725 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3726 mtx_unlock(&src->ps_mtx);
3727 }
3728
3729 int
3730 sigacts_shared(struct sigacts *ps)
3731 {
3732
3733 return (ps->ps_refcnt > 1);
3734 }
Cache object: c846fb56b050b94874466d9d7f9a36e9
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