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("$FreeBSD$");
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/ptrace.h>
67 #include <sys/posix4.h>
68 #include <sys/pioctl.h>
69 #include <sys/racct.h>
70 #include <sys/resourcevar.h>
71 #include <sys/sdt.h>
72 #include <sys/sbuf.h>
73 #include <sys/sleepqueue.h>
74 #include <sys/smp.h>
75 #include <sys/stat.h>
76 #include <sys/sx.h>
77 #include <sys/syscallsubr.h>
78 #include <sys/sysctl.h>
79 #include <sys/sysent.h>
80 #include <sys/syslog.h>
81 #include <sys/sysproto.h>
82 #include <sys/timers.h>
83 #include <sys/unistd.h>
84 #include <sys/wait.h>
85 #include <vm/vm.h>
86 #include <vm/vm_extern.h>
87 #include <vm/uma.h>
88
89 #include <sys/jail.h>
90
91 #include <machine/cpu.h>
92
93 #include <security/audit/audit.h>
94
95 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
96
97 SDT_PROVIDER_DECLARE(proc);
98 SDT_PROBE_DEFINE3(proc, , , signal__send,
99 "struct thread *", "struct proc *", "int");
100 SDT_PROBE_DEFINE2(proc, , , signal__clear,
101 "int", "ksiginfo_t *");
102 SDT_PROBE_DEFINE3(proc, , , signal__discard,
103 "struct thread *", "struct proc *", "int");
104
105 static int coredump(struct thread *);
106 static int killpg1(struct thread *td, int sig, int pgid, int all,
107 ksiginfo_t *ksi);
108 static int issignal(struct thread *td);
109 static int sigprop(int sig);
110 static void tdsigwakeup(struct thread *, int, sig_t, int);
111 static int sig_suspend_threads(struct thread *, struct proc *, int);
112 static int filt_sigattach(struct knote *kn);
113 static void filt_sigdetach(struct knote *kn);
114 static int filt_signal(struct knote *kn, long hint);
115 static struct thread *sigtd(struct proc *p, int sig, int prop);
116 static void sigqueue_start(void);
117
118 static uma_zone_t ksiginfo_zone = NULL;
119 struct filterops sig_filtops = {
120 .f_isfd = 0,
121 .f_attach = filt_sigattach,
122 .f_detach = filt_sigdetach,
123 .f_event = filt_signal,
124 };
125
126 static int kern_logsigexit = 1;
127 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
128 &kern_logsigexit, 0,
129 "Log processes quitting on abnormal signals to syslog(3)");
130
131 static int kern_forcesigexit = 1;
132 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
133 &kern_forcesigexit, 0, "Force trap signal to be handled");
134
135 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0,
136 "POSIX real time signal");
137
138 static int max_pending_per_proc = 128;
139 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
140 &max_pending_per_proc, 0, "Max pending signals per proc");
141
142 static int preallocate_siginfo = 1024;
143 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
144 &preallocate_siginfo, 0, "Preallocated signal memory size");
145
146 static int signal_overflow = 0;
147 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
148 &signal_overflow, 0, "Number of signals overflew");
149
150 static int signal_alloc_fail = 0;
151 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
152 &signal_alloc_fail, 0, "signals failed to be allocated");
153
154 static int kern_lognosys = 0;
155 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
156 "Log invalid syscalls");
157
158 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
159
160 /*
161 * Policy -- Can ucred cr1 send SIGIO to process cr2?
162 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
163 * in the right situations.
164 */
165 #define CANSIGIO(cr1, cr2) \
166 ((cr1)->cr_uid == 0 || \
167 (cr1)->cr_ruid == (cr2)->cr_ruid || \
168 (cr1)->cr_uid == (cr2)->cr_ruid || \
169 (cr1)->cr_ruid == (cr2)->cr_uid || \
170 (cr1)->cr_uid == (cr2)->cr_uid)
171
172 static int sugid_coredump;
173 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN,
174 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
175
176 static int capmode_coredump;
177 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN,
178 &capmode_coredump, 0, "Allow processes in capability mode to dump core");
179
180 static int do_coredump = 1;
181 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
182 &do_coredump, 0, "Enable/Disable coredumps");
183
184 static int set_core_nodump_flag = 0;
185 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
186 0, "Enable setting the NODUMP flag on coredump files");
187
188 static int coredump_devctl = 0;
189 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
190 0, "Generate a devctl notification when processes coredump");
191
192 /*
193 * Signal properties and actions.
194 * The array below categorizes the signals and their default actions
195 * according to the following properties:
196 */
197 #define SA_KILL 0x01 /* terminates process by default */
198 #define SA_CORE 0x02 /* ditto and coredumps */
199 #define SA_STOP 0x04 /* suspend process */
200 #define SA_TTYSTOP 0x08 /* ditto, from tty */
201 #define SA_IGNORE 0x10 /* ignore by default */
202 #define SA_CONT 0x20 /* continue if suspended */
203 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
204
205 static int sigproptbl[NSIG] = {
206 SA_KILL, /* SIGHUP */
207 SA_KILL, /* SIGINT */
208 SA_KILL|SA_CORE, /* SIGQUIT */
209 SA_KILL|SA_CORE, /* SIGILL */
210 SA_KILL|SA_CORE, /* SIGTRAP */
211 SA_KILL|SA_CORE, /* SIGABRT */
212 SA_KILL|SA_CORE, /* SIGEMT */
213 SA_KILL|SA_CORE, /* SIGFPE */
214 SA_KILL, /* SIGKILL */
215 SA_KILL|SA_CORE, /* SIGBUS */
216 SA_KILL|SA_CORE, /* SIGSEGV */
217 SA_KILL|SA_CORE, /* SIGSYS */
218 SA_KILL, /* SIGPIPE */
219 SA_KILL, /* SIGALRM */
220 SA_KILL, /* SIGTERM */
221 SA_IGNORE, /* SIGURG */
222 SA_STOP, /* SIGSTOP */
223 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
224 SA_IGNORE|SA_CONT, /* SIGCONT */
225 SA_IGNORE, /* SIGCHLD */
226 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
227 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
228 SA_IGNORE, /* SIGIO */
229 SA_KILL, /* SIGXCPU */
230 SA_KILL, /* SIGXFSZ */
231 SA_KILL, /* SIGVTALRM */
232 SA_KILL, /* SIGPROF */
233 SA_IGNORE, /* SIGWINCH */
234 SA_IGNORE, /* SIGINFO */
235 SA_KILL, /* SIGUSR1 */
236 SA_KILL, /* SIGUSR2 */
237 };
238
239 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
240
241 static void
sigqueue_start(void)242 sigqueue_start(void)
243 {
244 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
245 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
246 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
247 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
248 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
249 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
250 }
251
252 ksiginfo_t *
ksiginfo_alloc(int wait)253 ksiginfo_alloc(int wait)
254 {
255 int flags;
256
257 flags = M_ZERO;
258 if (! wait)
259 flags |= M_NOWAIT;
260 if (ksiginfo_zone != NULL)
261 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
262 return (NULL);
263 }
264
265 void
ksiginfo_free(ksiginfo_t * ksi)266 ksiginfo_free(ksiginfo_t *ksi)
267 {
268 uma_zfree(ksiginfo_zone, ksi);
269 }
270
271 static __inline int
ksiginfo_tryfree(ksiginfo_t * ksi)272 ksiginfo_tryfree(ksiginfo_t *ksi)
273 {
274 if (!(ksi->ksi_flags & KSI_EXT)) {
275 uma_zfree(ksiginfo_zone, ksi);
276 return (1);
277 }
278 return (0);
279 }
280
281 void
sigqueue_init(sigqueue_t * list,struct proc * p)282 sigqueue_init(sigqueue_t *list, struct proc *p)
283 {
284 SIGEMPTYSET(list->sq_signals);
285 SIGEMPTYSET(list->sq_kill);
286 SIGEMPTYSET(list->sq_ptrace);
287 TAILQ_INIT(&list->sq_list);
288 list->sq_proc = p;
289 list->sq_flags = SQ_INIT;
290 }
291
292 /*
293 * Get a signal's ksiginfo.
294 * Return:
295 * 0 - signal not found
296 * others - signal number
297 */
298 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)299 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
300 {
301 struct proc *p = sq->sq_proc;
302 struct ksiginfo *ksi, *next;
303 int count = 0;
304
305 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
306
307 if (!SIGISMEMBER(sq->sq_signals, signo))
308 return (0);
309
310 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
311 count++;
312 SIGDELSET(sq->sq_ptrace, signo);
313 si->ksi_flags |= KSI_PTRACE;
314 }
315 if (SIGISMEMBER(sq->sq_kill, signo)) {
316 count++;
317 if (count == 1)
318 SIGDELSET(sq->sq_kill, signo);
319 }
320
321 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
322 if (ksi->ksi_signo == signo) {
323 if (count == 0) {
324 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
325 ksi->ksi_sigq = NULL;
326 ksiginfo_copy(ksi, si);
327 if (ksiginfo_tryfree(ksi) && p != NULL)
328 p->p_pendingcnt--;
329 }
330 if (++count > 1)
331 break;
332 }
333 }
334
335 if (count <= 1)
336 SIGDELSET(sq->sq_signals, signo);
337 si->ksi_signo = signo;
338 return (signo);
339 }
340
341 void
sigqueue_take(ksiginfo_t * ksi)342 sigqueue_take(ksiginfo_t *ksi)
343 {
344 struct ksiginfo *kp;
345 struct proc *p;
346 sigqueue_t *sq;
347
348 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
349 return;
350
351 p = sq->sq_proc;
352 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
353 ksi->ksi_sigq = NULL;
354 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
355 p->p_pendingcnt--;
356
357 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
358 kp = TAILQ_NEXT(kp, ksi_link)) {
359 if (kp->ksi_signo == ksi->ksi_signo)
360 break;
361 }
362 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
363 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
364 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
365 }
366
367 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)368 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
369 {
370 struct proc *p = sq->sq_proc;
371 struct ksiginfo *ksi;
372 int ret = 0;
373
374 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
375
376 /*
377 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
378 * for these signals.
379 */
380 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
381 SIGADDSET(sq->sq_kill, signo);
382 goto out_set_bit;
383 }
384
385 /* directly insert the ksi, don't copy it */
386 if (si->ksi_flags & KSI_INS) {
387 if (si->ksi_flags & KSI_HEAD)
388 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
389 else
390 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
391 si->ksi_sigq = sq;
392 goto out_set_bit;
393 }
394
395 if (__predict_false(ksiginfo_zone == NULL)) {
396 SIGADDSET(sq->sq_kill, signo);
397 goto out_set_bit;
398 }
399
400 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
401 signal_overflow++;
402 ret = EAGAIN;
403 } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
404 signal_alloc_fail++;
405 ret = EAGAIN;
406 } else {
407 if (p != NULL)
408 p->p_pendingcnt++;
409 ksiginfo_copy(si, ksi);
410 ksi->ksi_signo = signo;
411 if (si->ksi_flags & KSI_HEAD)
412 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
413 else
414 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
415 ksi->ksi_sigq = sq;
416 }
417
418 if (ret != 0) {
419 if ((si->ksi_flags & KSI_PTRACE) != 0) {
420 SIGADDSET(sq->sq_ptrace, signo);
421 ret = 0;
422 goto out_set_bit;
423 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
424 (si->ksi_flags & KSI_SIGQ) == 0) {
425 SIGADDSET(sq->sq_kill, signo);
426 ret = 0;
427 goto out_set_bit;
428 }
429 return (ret);
430 }
431
432 out_set_bit:
433 SIGADDSET(sq->sq_signals, signo);
434 return (ret);
435 }
436
437 void
sigqueue_flush(sigqueue_t * sq)438 sigqueue_flush(sigqueue_t *sq)
439 {
440 struct proc *p = sq->sq_proc;
441 ksiginfo_t *ksi;
442
443 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
444
445 if (p != NULL)
446 PROC_LOCK_ASSERT(p, MA_OWNED);
447
448 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
449 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
450 ksi->ksi_sigq = NULL;
451 if (ksiginfo_tryfree(ksi) && p != NULL)
452 p->p_pendingcnt--;
453 }
454
455 SIGEMPTYSET(sq->sq_signals);
456 SIGEMPTYSET(sq->sq_kill);
457 SIGEMPTYSET(sq->sq_ptrace);
458 }
459
460 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)461 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
462 {
463 sigset_t tmp;
464 struct proc *p1, *p2;
465 ksiginfo_t *ksi, *next;
466
467 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
468 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
469 p1 = src->sq_proc;
470 p2 = dst->sq_proc;
471 /* Move siginfo to target list */
472 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
473 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
474 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
475 if (p1 != NULL)
476 p1->p_pendingcnt--;
477 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
478 ksi->ksi_sigq = dst;
479 if (p2 != NULL)
480 p2->p_pendingcnt++;
481 }
482 }
483
484 /* Move pending bits to target list */
485 tmp = src->sq_kill;
486 SIGSETAND(tmp, *set);
487 SIGSETOR(dst->sq_kill, tmp);
488 SIGSETNAND(src->sq_kill, tmp);
489
490 tmp = src->sq_ptrace;
491 SIGSETAND(tmp, *set);
492 SIGSETOR(dst->sq_ptrace, tmp);
493 SIGSETNAND(src->sq_ptrace, tmp);
494
495 tmp = src->sq_signals;
496 SIGSETAND(tmp, *set);
497 SIGSETOR(dst->sq_signals, tmp);
498 SIGSETNAND(src->sq_signals, tmp);
499 }
500
501 #if 0
502 static void
503 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
504 {
505 sigset_t set;
506
507 SIGEMPTYSET(set);
508 SIGADDSET(set, signo);
509 sigqueue_move_set(src, dst, &set);
510 }
511 #endif
512
513 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)514 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
515 {
516 struct proc *p = sq->sq_proc;
517 ksiginfo_t *ksi, *next;
518
519 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
520
521 /* Remove siginfo queue */
522 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
523 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
524 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
525 ksi->ksi_sigq = NULL;
526 if (ksiginfo_tryfree(ksi) && p != NULL)
527 p->p_pendingcnt--;
528 }
529 }
530 SIGSETNAND(sq->sq_kill, *set);
531 SIGSETNAND(sq->sq_ptrace, *set);
532 SIGSETNAND(sq->sq_signals, *set);
533 }
534
535 void
sigqueue_delete(sigqueue_t * sq,int signo)536 sigqueue_delete(sigqueue_t *sq, int signo)
537 {
538 sigset_t set;
539
540 SIGEMPTYSET(set);
541 SIGADDSET(set, signo);
542 sigqueue_delete_set(sq, &set);
543 }
544
545 /* Remove a set of signals for a process */
546 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)547 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
548 {
549 sigqueue_t worklist;
550 struct thread *td0;
551
552 PROC_LOCK_ASSERT(p, MA_OWNED);
553
554 sigqueue_init(&worklist, NULL);
555 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
556
557 FOREACH_THREAD_IN_PROC(p, td0)
558 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
559
560 sigqueue_flush(&worklist);
561 }
562
563 void
sigqueue_delete_proc(struct proc * p,int signo)564 sigqueue_delete_proc(struct proc *p, int signo)
565 {
566 sigset_t set;
567
568 SIGEMPTYSET(set);
569 SIGADDSET(set, signo);
570 sigqueue_delete_set_proc(p, &set);
571 }
572
573 static void
sigqueue_delete_stopmask_proc(struct proc * p)574 sigqueue_delete_stopmask_proc(struct proc *p)
575 {
576 sigset_t set;
577
578 SIGEMPTYSET(set);
579 SIGADDSET(set, SIGSTOP);
580 SIGADDSET(set, SIGTSTP);
581 SIGADDSET(set, SIGTTIN);
582 SIGADDSET(set, SIGTTOU);
583 sigqueue_delete_set_proc(p, &set);
584 }
585
586 /*
587 * Determine signal that should be delivered to thread td, the current
588 * thread, 0 if none. If there is a pending stop signal with default
589 * action, the process stops in issignal().
590 */
591 int
cursig(struct thread * td)592 cursig(struct thread *td)
593 {
594 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
595 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
596 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
597 return (SIGPENDING(td) ? issignal(td) : 0);
598 }
599
600 /*
601 * Arrange for ast() to handle unmasked pending signals on return to user
602 * mode. This must be called whenever a signal is added to td_sigqueue or
603 * unmasked in td_sigmask.
604 */
605 void
signotify(struct thread * td)606 signotify(struct thread *td)
607 {
608 struct proc *p;
609
610 p = td->td_proc;
611
612 PROC_LOCK_ASSERT(p, MA_OWNED);
613
614 if (SIGPENDING(td)) {
615 thread_lock(td);
616 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
617 thread_unlock(td);
618 }
619 }
620
621 /*
622 * Returns 1 (true) if altstack is configured for the thread, and the
623 * passed stack bottom address falls into the altstack range. Handles
624 * the 43 compat special case where the alt stack size is zero.
625 */
626 int
sigonstack(size_t sp)627 sigonstack(size_t sp)
628 {
629 struct thread *td;
630
631 td = curthread;
632 if ((td->td_pflags & TDP_ALTSTACK) == 0)
633 return (0);
634 #if defined(COMPAT_43)
635 if (td->td_sigstk.ss_size == 0)
636 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0);
637 #endif
638 return (sp >= (size_t)td->td_sigstk.ss_sp &&
639 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp);
640 }
641
642 static __inline int
sigprop(int sig)643 sigprop(int sig)
644 {
645
646 if (sig > 0 && sig < NSIG)
647 return (sigproptbl[_SIG_IDX(sig)]);
648 return (0);
649 }
650
651 int
sig_ffs(sigset_t * set)652 sig_ffs(sigset_t *set)
653 {
654 int i;
655
656 for (i = 0; i < _SIG_WORDS; i++)
657 if (set->__bits[i])
658 return (ffs(set->__bits[i]) + (i * 32));
659 return (0);
660 }
661
662 static bool
sigact_flag_test(const struct sigaction * act,int flag)663 sigact_flag_test(const struct sigaction *act, int flag)
664 {
665
666 /*
667 * SA_SIGINFO is reset when signal disposition is set to
668 * ignore or default. Other flags are kept according to user
669 * settings.
670 */
671 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
672 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
673 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
674 }
675
676 /*
677 * kern_sigaction
678 * sigaction
679 * freebsd4_sigaction
680 * osigaction
681 */
682 int
kern_sigaction(struct thread * td,int sig,const struct sigaction * act,struct sigaction * oact,int flags)683 kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
684 struct sigaction *oact, int flags)
685 {
686 struct sigacts *ps;
687 struct proc *p = td->td_proc;
688
689 if (!_SIG_VALID(sig))
690 return (EINVAL);
691 if (act != NULL && act->sa_handler != SIG_DFL &&
692 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
693 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
694 SA_NOCLDWAIT | SA_SIGINFO)) != 0)
695 return (EINVAL);
696
697 PROC_LOCK(p);
698 ps = p->p_sigacts;
699 mtx_lock(&ps->ps_mtx);
700 if (oact) {
701 memset(oact, 0, sizeof(*oact));
702 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
703 if (SIGISMEMBER(ps->ps_sigonstack, sig))
704 oact->sa_flags |= SA_ONSTACK;
705 if (!SIGISMEMBER(ps->ps_sigintr, sig))
706 oact->sa_flags |= SA_RESTART;
707 if (SIGISMEMBER(ps->ps_sigreset, sig))
708 oact->sa_flags |= SA_RESETHAND;
709 if (SIGISMEMBER(ps->ps_signodefer, sig))
710 oact->sa_flags |= SA_NODEFER;
711 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
712 oact->sa_flags |= SA_SIGINFO;
713 oact->sa_sigaction =
714 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
715 } else
716 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
717 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
718 oact->sa_flags |= SA_NOCLDSTOP;
719 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
720 oact->sa_flags |= SA_NOCLDWAIT;
721 }
722 if (act) {
723 if ((sig == SIGKILL || sig == SIGSTOP) &&
724 act->sa_handler != SIG_DFL) {
725 mtx_unlock(&ps->ps_mtx);
726 PROC_UNLOCK(p);
727 return (EINVAL);
728 }
729
730 /*
731 * Change setting atomically.
732 */
733
734 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
735 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
736 if (sigact_flag_test(act, SA_SIGINFO)) {
737 ps->ps_sigact[_SIG_IDX(sig)] =
738 (__sighandler_t *)act->sa_sigaction;
739 SIGADDSET(ps->ps_siginfo, sig);
740 } else {
741 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
742 SIGDELSET(ps->ps_siginfo, sig);
743 }
744 if (!sigact_flag_test(act, SA_RESTART))
745 SIGADDSET(ps->ps_sigintr, sig);
746 else
747 SIGDELSET(ps->ps_sigintr, sig);
748 if (sigact_flag_test(act, SA_ONSTACK))
749 SIGADDSET(ps->ps_sigonstack, sig);
750 else
751 SIGDELSET(ps->ps_sigonstack, sig);
752 if (sigact_flag_test(act, SA_RESETHAND))
753 SIGADDSET(ps->ps_sigreset, sig);
754 else
755 SIGDELSET(ps->ps_sigreset, sig);
756 if (sigact_flag_test(act, SA_NODEFER))
757 SIGADDSET(ps->ps_signodefer, sig);
758 else
759 SIGDELSET(ps->ps_signodefer, sig);
760 if (sig == SIGCHLD) {
761 if (act->sa_flags & SA_NOCLDSTOP)
762 ps->ps_flag |= PS_NOCLDSTOP;
763 else
764 ps->ps_flag &= ~PS_NOCLDSTOP;
765 if (act->sa_flags & SA_NOCLDWAIT) {
766 /*
767 * Paranoia: since SA_NOCLDWAIT is implemented
768 * by reparenting the dying child to PID 1 (and
769 * trust it to reap the zombie), PID 1 itself
770 * is forbidden to set SA_NOCLDWAIT.
771 */
772 if (p->p_pid == 1)
773 ps->ps_flag &= ~PS_NOCLDWAIT;
774 else
775 ps->ps_flag |= PS_NOCLDWAIT;
776 } else
777 ps->ps_flag &= ~PS_NOCLDWAIT;
778 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
779 ps->ps_flag |= PS_CLDSIGIGN;
780 else
781 ps->ps_flag &= ~PS_CLDSIGIGN;
782 }
783 /*
784 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
785 * and for signals set to SIG_DFL where the default is to
786 * ignore. However, don't put SIGCONT in ps_sigignore, as we
787 * have to restart the process.
788 */
789 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
790 (sigprop(sig) & SA_IGNORE &&
791 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
792 /* never to be seen again */
793 sigqueue_delete_proc(p, sig);
794 if (sig != SIGCONT)
795 /* easier in psignal */
796 SIGADDSET(ps->ps_sigignore, sig);
797 SIGDELSET(ps->ps_sigcatch, sig);
798 } else {
799 SIGDELSET(ps->ps_sigignore, sig);
800 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
801 SIGDELSET(ps->ps_sigcatch, sig);
802 else
803 SIGADDSET(ps->ps_sigcatch, sig);
804 }
805 #ifdef COMPAT_FREEBSD4
806 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
807 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
808 (flags & KSA_FREEBSD4) == 0)
809 SIGDELSET(ps->ps_freebsd4, sig);
810 else
811 SIGADDSET(ps->ps_freebsd4, sig);
812 #endif
813 #ifdef COMPAT_43
814 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
815 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
816 (flags & KSA_OSIGSET) == 0)
817 SIGDELSET(ps->ps_osigset, sig);
818 else
819 SIGADDSET(ps->ps_osigset, sig);
820 #endif
821 }
822 mtx_unlock(&ps->ps_mtx);
823 PROC_UNLOCK(p);
824 return (0);
825 }
826
827 #ifndef _SYS_SYSPROTO_H_
828 struct sigaction_args {
829 int sig;
830 struct sigaction *act;
831 struct sigaction *oact;
832 };
833 #endif
834 int
sys_sigaction(struct thread * td,struct sigaction_args * uap)835 sys_sigaction(struct thread *td, struct sigaction_args *uap)
836 {
837 struct sigaction act, oact;
838 struct sigaction *actp, *oactp;
839 int error;
840
841 actp = (uap->act != NULL) ? &act : NULL;
842 oactp = (uap->oact != NULL) ? &oact : NULL;
843 if (actp) {
844 error = copyin(uap->act, actp, sizeof(act));
845 if (error)
846 return (error);
847 }
848 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
849 if (oactp && !error)
850 error = copyout(oactp, uap->oact, sizeof(oact));
851 return (error);
852 }
853
854 #ifdef COMPAT_FREEBSD4
855 #ifndef _SYS_SYSPROTO_H_
856 struct freebsd4_sigaction_args {
857 int sig;
858 struct sigaction *act;
859 struct sigaction *oact;
860 };
861 #endif
862 int
freebsd4_sigaction(struct thread * td,struct freebsd4_sigaction_args * uap)863 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
864 {
865 struct sigaction act, oact;
866 struct sigaction *actp, *oactp;
867 int error;
868
869
870 actp = (uap->act != NULL) ? &act : NULL;
871 oactp = (uap->oact != NULL) ? &oact : NULL;
872 if (actp) {
873 error = copyin(uap->act, actp, sizeof(act));
874 if (error)
875 return (error);
876 }
877 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
878 if (oactp && !error)
879 error = copyout(oactp, uap->oact, sizeof(oact));
880 return (error);
881 }
882 #endif /* COMAPT_FREEBSD4 */
883
884 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
885 #ifndef _SYS_SYSPROTO_H_
886 struct osigaction_args {
887 int signum;
888 struct osigaction *nsa;
889 struct osigaction *osa;
890 };
891 #endif
892 int
osigaction(struct thread * td,struct osigaction_args * uap)893 osigaction(struct thread *td, struct osigaction_args *uap)
894 {
895 struct osigaction sa;
896 struct sigaction nsa, osa;
897 struct sigaction *nsap, *osap;
898 int error;
899
900 if (uap->signum <= 0 || uap->signum >= ONSIG)
901 return (EINVAL);
902
903 nsap = (uap->nsa != NULL) ? &nsa : NULL;
904 osap = (uap->osa != NULL) ? &osa : NULL;
905
906 if (nsap) {
907 error = copyin(uap->nsa, &sa, sizeof(sa));
908 if (error)
909 return (error);
910 nsap->sa_handler = sa.sa_handler;
911 nsap->sa_flags = sa.sa_flags;
912 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
913 }
914 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
915 if (osap && !error) {
916 sa.sa_handler = osap->sa_handler;
917 sa.sa_flags = osap->sa_flags;
918 SIG2OSIG(osap->sa_mask, sa.sa_mask);
919 error = copyout(&sa, uap->osa, sizeof(sa));
920 }
921 return (error);
922 }
923
924 #if !defined(__i386__)
925 /* Avoid replicating the same stub everywhere */
926 int
osigreturn(struct thread * td,struct osigreturn_args * uap)927 osigreturn(struct thread *td, struct osigreturn_args *uap)
928 {
929
930 return (nosys(td, (struct nosys_args *)uap));
931 }
932 #endif
933 #endif /* COMPAT_43 */
934
935 /*
936 * Initialize signal state for process 0;
937 * set to ignore signals that are ignored by default.
938 */
939 void
siginit(struct proc * p)940 siginit(struct proc *p)
941 {
942 int i;
943 struct sigacts *ps;
944
945 PROC_LOCK(p);
946 ps = p->p_sigacts;
947 mtx_lock(&ps->ps_mtx);
948 for (i = 1; i <= NSIG; i++) {
949 if (sigprop(i) & SA_IGNORE && i != SIGCONT) {
950 SIGADDSET(ps->ps_sigignore, i);
951 }
952 }
953 mtx_unlock(&ps->ps_mtx);
954 PROC_UNLOCK(p);
955 }
956
957 /*
958 * Reset specified signal to the default disposition.
959 */
960 static void
sigdflt(struct sigacts * ps,int sig)961 sigdflt(struct sigacts *ps, int sig)
962 {
963
964 mtx_assert(&ps->ps_mtx, MA_OWNED);
965 SIGDELSET(ps->ps_sigcatch, sig);
966 if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT)
967 SIGADDSET(ps->ps_sigignore, sig);
968 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
969 SIGDELSET(ps->ps_siginfo, sig);
970 }
971
972 /*
973 * Reset signals for an exec of the specified process.
974 */
975 void
execsigs(struct proc * p)976 execsigs(struct proc *p)
977 {
978 sigset_t osigignore;
979 struct sigacts *ps;
980 int sig;
981 struct thread *td;
982
983 /*
984 * Reset caught signals. Held signals remain held
985 * through td_sigmask (unless they were caught,
986 * and are now ignored by default).
987 */
988 PROC_LOCK_ASSERT(p, MA_OWNED);
989 ps = p->p_sigacts;
990 mtx_lock(&ps->ps_mtx);
991 sig_drop_caught(p);
992
993 /*
994 * As CloudABI processes cannot modify signal handlers, fully
995 * reset all signals to their default behavior. Do ignore
996 * SIGPIPE, as it would otherwise be impossible to recover from
997 * writes to broken pipes and sockets.
998 */
999 if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) {
1000 osigignore = ps->ps_sigignore;
1001 while (SIGNOTEMPTY(osigignore)) {
1002 sig = sig_ffs(&osigignore);
1003 SIGDELSET(osigignore, sig);
1004 if (sig != SIGPIPE)
1005 sigdflt(ps, sig);
1006 }
1007 SIGADDSET(ps->ps_sigignore, SIGPIPE);
1008 }
1009
1010 /*
1011 * Reset stack state to the user stack.
1012 * Clear set of signals caught on the signal stack.
1013 */
1014 td = curthread;
1015 MPASS(td->td_proc == p);
1016 td->td_sigstk.ss_flags = SS_DISABLE;
1017 td->td_sigstk.ss_size = 0;
1018 td->td_sigstk.ss_sp = 0;
1019 td->td_pflags &= ~TDP_ALTSTACK;
1020 /*
1021 * Reset no zombies if child dies flag as Solaris does.
1022 */
1023 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1024 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1025 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1026 mtx_unlock(&ps->ps_mtx);
1027 }
1028
1029 /*
1030 * kern_sigprocmask()
1031 *
1032 * Manipulate signal mask.
1033 */
1034 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)1035 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1036 int flags)
1037 {
1038 sigset_t new_block, oset1;
1039 struct proc *p;
1040 int error;
1041
1042 p = td->td_proc;
1043 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1044 PROC_LOCK_ASSERT(p, MA_OWNED);
1045 else
1046 PROC_LOCK(p);
1047 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1048 ? MA_OWNED : MA_NOTOWNED);
1049 if (oset != NULL)
1050 *oset = td->td_sigmask;
1051
1052 error = 0;
1053 if (set != NULL) {
1054 switch (how) {
1055 case SIG_BLOCK:
1056 SIG_CANTMASK(*set);
1057 oset1 = td->td_sigmask;
1058 SIGSETOR(td->td_sigmask, *set);
1059 new_block = td->td_sigmask;
1060 SIGSETNAND(new_block, oset1);
1061 break;
1062 case SIG_UNBLOCK:
1063 SIGSETNAND(td->td_sigmask, *set);
1064 signotify(td);
1065 goto out;
1066 case SIG_SETMASK:
1067 SIG_CANTMASK(*set);
1068 oset1 = td->td_sigmask;
1069 if (flags & SIGPROCMASK_OLD)
1070 SIGSETLO(td->td_sigmask, *set);
1071 else
1072 td->td_sigmask = *set;
1073 new_block = td->td_sigmask;
1074 SIGSETNAND(new_block, oset1);
1075 signotify(td);
1076 break;
1077 default:
1078 error = EINVAL;
1079 goto out;
1080 }
1081
1082 /*
1083 * The new_block set contains signals that were not previously
1084 * blocked, but are blocked now.
1085 *
1086 * In case we block any signal that was not previously blocked
1087 * for td, and process has the signal pending, try to schedule
1088 * signal delivery to some thread that does not block the
1089 * signal, possibly waking it up.
1090 */
1091 if (p->p_numthreads != 1)
1092 reschedule_signals(p, new_block, flags);
1093 }
1094
1095 out:
1096 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1097 PROC_UNLOCK(p);
1098 return (error);
1099 }
1100
1101 #ifndef _SYS_SYSPROTO_H_
1102 struct sigprocmask_args {
1103 int how;
1104 const sigset_t *set;
1105 sigset_t *oset;
1106 };
1107 #endif
1108 int
sys_sigprocmask(struct thread * td,struct sigprocmask_args * uap)1109 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
1110 {
1111 sigset_t set, oset;
1112 sigset_t *setp, *osetp;
1113 int error;
1114
1115 setp = (uap->set != NULL) ? &set : NULL;
1116 osetp = (uap->oset != NULL) ? &oset : NULL;
1117 if (setp) {
1118 error = copyin(uap->set, setp, sizeof(set));
1119 if (error)
1120 return (error);
1121 }
1122 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1123 if (osetp && !error) {
1124 error = copyout(osetp, uap->oset, sizeof(oset));
1125 }
1126 return (error);
1127 }
1128
1129 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1130 #ifndef _SYS_SYSPROTO_H_
1131 struct osigprocmask_args {
1132 int how;
1133 osigset_t mask;
1134 };
1135 #endif
1136 int
osigprocmask(struct thread * td,struct osigprocmask_args * uap)1137 osigprocmask(struct thread *td, struct osigprocmask_args *uap)
1138 {
1139 sigset_t set, oset;
1140 int error;
1141
1142 OSIG2SIG(uap->mask, set);
1143 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1144 SIG2OSIG(oset, td->td_retval[0]);
1145 return (error);
1146 }
1147 #endif /* COMPAT_43 */
1148
1149 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1150 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1151 {
1152 ksiginfo_t ksi;
1153 sigset_t set;
1154 int error;
1155
1156 error = copyin(uap->set, &set, sizeof(set));
1157 if (error) {
1158 td->td_retval[0] = error;
1159 return (0);
1160 }
1161
1162 error = kern_sigtimedwait(td, set, &ksi, NULL);
1163 if (error) {
1164 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1165 error = ERESTART;
1166 if (error == ERESTART)
1167 return (error);
1168 td->td_retval[0] = error;
1169 return (0);
1170 }
1171
1172 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1173 td->td_retval[0] = error;
1174 return (0);
1175 }
1176
1177 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1178 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1179 {
1180 struct timespec ts;
1181 struct timespec *timeout;
1182 sigset_t set;
1183 ksiginfo_t ksi;
1184 int error;
1185
1186 if (uap->timeout) {
1187 error = copyin(uap->timeout, &ts, sizeof(ts));
1188 if (error)
1189 return (error);
1190
1191 timeout = &ts;
1192 } else
1193 timeout = NULL;
1194
1195 error = copyin(uap->set, &set, sizeof(set));
1196 if (error)
1197 return (error);
1198
1199 error = kern_sigtimedwait(td, set, &ksi, timeout);
1200 if (error)
1201 return (error);
1202
1203 if (uap->info)
1204 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1205
1206 if (error == 0)
1207 td->td_retval[0] = ksi.ksi_signo;
1208 return (error);
1209 }
1210
1211 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1212 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1213 {
1214 ksiginfo_t ksi;
1215 sigset_t set;
1216 int error;
1217
1218 error = copyin(uap->set, &set, sizeof(set));
1219 if (error)
1220 return (error);
1221
1222 error = kern_sigtimedwait(td, set, &ksi, NULL);
1223 if (error)
1224 return (error);
1225
1226 if (uap->info)
1227 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1228
1229 if (error == 0)
1230 td->td_retval[0] = ksi.ksi_signo;
1231 return (error);
1232 }
1233
1234 static void
proc_td_siginfo_capture(struct thread * td,siginfo_t * si)1235 proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
1236 {
1237 struct thread *thr;
1238
1239 FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
1240 if (thr == td)
1241 thr->td_si = *si;
1242 else
1243 thr->td_si.si_signo = 0;
1244 }
1245 }
1246
1247 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1248 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1249 struct timespec *timeout)
1250 {
1251 struct sigacts *ps;
1252 sigset_t saved_mask, new_block;
1253 struct proc *p;
1254 int error, sig, timo, timevalid = 0;
1255 struct timespec rts, ets, ts;
1256 struct timeval tv;
1257 bool traced;
1258
1259 p = td->td_proc;
1260 error = 0;
1261 ets.tv_sec = 0;
1262 ets.tv_nsec = 0;
1263 traced = false;
1264
1265 if (timeout != NULL) {
1266 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1267 timevalid = 1;
1268 getnanouptime(&rts);
1269 ets = rts;
1270 timespecadd(&ets, timeout);
1271 }
1272 }
1273 ksiginfo_init(ksi);
1274 /* Some signals can not be waited for. */
1275 SIG_CANTMASK(waitset);
1276 ps = p->p_sigacts;
1277 PROC_LOCK(p);
1278 saved_mask = td->td_sigmask;
1279 SIGSETNAND(td->td_sigmask, waitset);
1280 for (;;) {
1281 mtx_lock(&ps->ps_mtx);
1282 sig = cursig(td);
1283 mtx_unlock(&ps->ps_mtx);
1284 KASSERT(sig >= 0, ("sig %d", sig));
1285 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1286 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1287 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1288 error = 0;
1289 break;
1290 }
1291 }
1292
1293 if (error != 0)
1294 break;
1295
1296 /*
1297 * POSIX says this must be checked after looking for pending
1298 * signals.
1299 */
1300 if (timeout != NULL) {
1301 if (!timevalid) {
1302 error = EINVAL;
1303 break;
1304 }
1305 getnanouptime(&rts);
1306 if (timespeccmp(&rts, &ets, >=)) {
1307 error = EAGAIN;
1308 break;
1309 }
1310 ts = ets;
1311 timespecsub(&ts, &rts);
1312 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1313 timo = tvtohz(&tv);
1314 } else {
1315 timo = 0;
1316 }
1317
1318 if (traced) {
1319 error = EINTR;
1320 break;
1321 }
1322
1323 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
1324
1325 if (timeout != NULL) {
1326 if (error == ERESTART) {
1327 /* Timeout can not be restarted. */
1328 error = EINTR;
1329 } else if (error == EAGAIN) {
1330 /* We will calculate timeout by ourself. */
1331 error = 0;
1332 }
1333 }
1334
1335 /*
1336 * If PTRACE_SCE or PTRACE_SCX were set after
1337 * userspace entered the syscall, return spurious
1338 * EINTR after wait was done. Only do this as last
1339 * resort after rechecking for possible queued signals
1340 * and expired timeouts.
1341 */
1342 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0)
1343 traced = true;
1344 }
1345
1346 new_block = saved_mask;
1347 SIGSETNAND(new_block, td->td_sigmask);
1348 td->td_sigmask = saved_mask;
1349 /*
1350 * Fewer signals can be delivered to us, reschedule signal
1351 * notification.
1352 */
1353 if (p->p_numthreads != 1)
1354 reschedule_signals(p, new_block, 0);
1355
1356 if (error == 0) {
1357 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1358
1359 if (ksi->ksi_code == SI_TIMER)
1360 itimer_accept(p, ksi->ksi_timerid, ksi);
1361
1362 #ifdef KTRACE
1363 if (KTRPOINT(td, KTR_PSIG)) {
1364 sig_t action;
1365
1366 mtx_lock(&ps->ps_mtx);
1367 action = ps->ps_sigact[_SIG_IDX(sig)];
1368 mtx_unlock(&ps->ps_mtx);
1369 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1370 }
1371 #endif
1372 if (sig == SIGKILL) {
1373 proc_td_siginfo_capture(td, &ksi->ksi_info);
1374 sigexit(td, sig);
1375 }
1376 }
1377 PROC_UNLOCK(p);
1378 return (error);
1379 }
1380
1381 #ifndef _SYS_SYSPROTO_H_
1382 struct sigpending_args {
1383 sigset_t *set;
1384 };
1385 #endif
1386 int
sys_sigpending(struct thread * td,struct sigpending_args * uap)1387 sys_sigpending(struct thread *td, struct sigpending_args *uap)
1388 {
1389 struct proc *p = td->td_proc;
1390 sigset_t pending;
1391
1392 PROC_LOCK(p);
1393 pending = p->p_sigqueue.sq_signals;
1394 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1395 PROC_UNLOCK(p);
1396 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1397 }
1398
1399 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1400 #ifndef _SYS_SYSPROTO_H_
1401 struct osigpending_args {
1402 int dummy;
1403 };
1404 #endif
1405 int
osigpending(struct thread * td,struct osigpending_args * uap)1406 osigpending(struct thread *td, struct osigpending_args *uap)
1407 {
1408 struct proc *p = td->td_proc;
1409 sigset_t pending;
1410
1411 PROC_LOCK(p);
1412 pending = p->p_sigqueue.sq_signals;
1413 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1414 PROC_UNLOCK(p);
1415 SIG2OSIG(pending, td->td_retval[0]);
1416 return (0);
1417 }
1418 #endif /* COMPAT_43 */
1419
1420 #if defined(COMPAT_43)
1421 /*
1422 * Generalized interface signal handler, 4.3-compatible.
1423 */
1424 #ifndef _SYS_SYSPROTO_H_
1425 struct osigvec_args {
1426 int signum;
1427 struct sigvec *nsv;
1428 struct sigvec *osv;
1429 };
1430 #endif
1431 /* ARGSUSED */
1432 int
osigvec(struct thread * td,struct osigvec_args * uap)1433 osigvec(struct thread *td, struct osigvec_args *uap)
1434 {
1435 struct sigvec vec;
1436 struct sigaction nsa, osa;
1437 struct sigaction *nsap, *osap;
1438 int error;
1439
1440 if (uap->signum <= 0 || uap->signum >= ONSIG)
1441 return (EINVAL);
1442 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1443 osap = (uap->osv != NULL) ? &osa : NULL;
1444 if (nsap) {
1445 error = copyin(uap->nsv, &vec, sizeof(vec));
1446 if (error)
1447 return (error);
1448 nsap->sa_handler = vec.sv_handler;
1449 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1450 nsap->sa_flags = vec.sv_flags;
1451 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1452 }
1453 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1454 if (osap && !error) {
1455 vec.sv_handler = osap->sa_handler;
1456 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1457 vec.sv_flags = osap->sa_flags;
1458 vec.sv_flags &= ~SA_NOCLDWAIT;
1459 vec.sv_flags ^= SA_RESTART;
1460 error = copyout(&vec, uap->osv, sizeof(vec));
1461 }
1462 return (error);
1463 }
1464
1465 #ifndef _SYS_SYSPROTO_H_
1466 struct osigblock_args {
1467 int mask;
1468 };
1469 #endif
1470 int
osigblock(struct thread * td,struct osigblock_args * uap)1471 osigblock(struct thread *td, struct osigblock_args *uap)
1472 {
1473 sigset_t set, oset;
1474
1475 OSIG2SIG(uap->mask, set);
1476 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1477 SIG2OSIG(oset, td->td_retval[0]);
1478 return (0);
1479 }
1480
1481 #ifndef _SYS_SYSPROTO_H_
1482 struct osigsetmask_args {
1483 int mask;
1484 };
1485 #endif
1486 int
osigsetmask(struct thread * td,struct osigsetmask_args * uap)1487 osigsetmask(struct thread *td, struct osigsetmask_args *uap)
1488 {
1489 sigset_t set, oset;
1490
1491 OSIG2SIG(uap->mask, set);
1492 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1493 SIG2OSIG(oset, td->td_retval[0]);
1494 return (0);
1495 }
1496 #endif /* COMPAT_43 */
1497
1498 /*
1499 * Suspend calling thread until signal, providing mask to be set in the
1500 * meantime.
1501 */
1502 #ifndef _SYS_SYSPROTO_H_
1503 struct sigsuspend_args {
1504 const sigset_t *sigmask;
1505 };
1506 #endif
1507 /* ARGSUSED */
1508 int
sys_sigsuspend(struct thread * td,struct sigsuspend_args * uap)1509 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
1510 {
1511 sigset_t mask;
1512 int error;
1513
1514 error = copyin(uap->sigmask, &mask, sizeof(mask));
1515 if (error)
1516 return (error);
1517 return (kern_sigsuspend(td, mask));
1518 }
1519
1520 int
kern_sigsuspend(struct thread * td,sigset_t mask)1521 kern_sigsuspend(struct thread *td, sigset_t mask)
1522 {
1523 struct proc *p = td->td_proc;
1524 int has_sig, sig;
1525
1526 /*
1527 * When returning from sigsuspend, we want
1528 * the old mask to be restored after the
1529 * signal handler has finished. Thus, we
1530 * save it here and mark the sigacts structure
1531 * to indicate this.
1532 */
1533 PROC_LOCK(p);
1534 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1535 SIGPROCMASK_PROC_LOCKED);
1536 td->td_pflags |= TDP_OLDMASK;
1537
1538 /*
1539 * Process signals now. Otherwise, we can get spurious wakeup
1540 * due to signal entered process queue, but delivered to other
1541 * thread. But sigsuspend should return only on signal
1542 * delivery.
1543 */
1544 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1545 for (has_sig = 0; !has_sig;) {
1546 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1547 0) == 0)
1548 /* void */;
1549 thread_suspend_check(0);
1550 mtx_lock(&p->p_sigacts->ps_mtx);
1551 while ((sig = cursig(td)) != 0) {
1552 KASSERT(sig >= 0, ("sig %d", sig));
1553 has_sig += postsig(sig);
1554 }
1555 mtx_unlock(&p->p_sigacts->ps_mtx);
1556
1557 /*
1558 * If PTRACE_SCE or PTRACE_SCX were set after
1559 * userspace entered the syscall, return spurious
1560 * EINTR.
1561 */
1562 if ((p->p_ptevents & PTRACE_SYSCALL) != 0)
1563 has_sig += 1;
1564 }
1565 PROC_UNLOCK(p);
1566 td->td_errno = EINTR;
1567 td->td_pflags |= TDP_NERRNO;
1568 return (EJUSTRETURN);
1569 }
1570
1571 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1572 /*
1573 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1574 * convention: libc stub passes mask, not pointer, to save a copyin.
1575 */
1576 #ifndef _SYS_SYSPROTO_H_
1577 struct osigsuspend_args {
1578 osigset_t mask;
1579 };
1580 #endif
1581 /* ARGSUSED */
1582 int
osigsuspend(struct thread * td,struct osigsuspend_args * uap)1583 osigsuspend(struct thread *td, struct osigsuspend_args *uap)
1584 {
1585 sigset_t mask;
1586
1587 OSIG2SIG(uap->mask, mask);
1588 return (kern_sigsuspend(td, mask));
1589 }
1590 #endif /* COMPAT_43 */
1591
1592 #if defined(COMPAT_43)
1593 #ifndef _SYS_SYSPROTO_H_
1594 struct osigstack_args {
1595 struct sigstack *nss;
1596 struct sigstack *oss;
1597 };
1598 #endif
1599 /* ARGSUSED */
1600 int
osigstack(struct thread * td,struct osigstack_args * uap)1601 osigstack(struct thread *td, struct osigstack_args *uap)
1602 {
1603 struct sigstack nss, oss;
1604 int error = 0;
1605
1606 if (uap->nss != NULL) {
1607 error = copyin(uap->nss, &nss, sizeof(nss));
1608 if (error)
1609 return (error);
1610 }
1611 oss.ss_sp = td->td_sigstk.ss_sp;
1612 oss.ss_onstack = sigonstack(cpu_getstack(td));
1613 if (uap->nss != NULL) {
1614 td->td_sigstk.ss_sp = nss.ss_sp;
1615 td->td_sigstk.ss_size = 0;
1616 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1617 td->td_pflags |= TDP_ALTSTACK;
1618 }
1619 if (uap->oss != NULL)
1620 error = copyout(&oss, uap->oss, sizeof(oss));
1621
1622 return (error);
1623 }
1624 #endif /* COMPAT_43 */
1625
1626 #ifndef _SYS_SYSPROTO_H_
1627 struct sigaltstack_args {
1628 stack_t *ss;
1629 stack_t *oss;
1630 };
1631 #endif
1632 /* ARGSUSED */
1633 int
sys_sigaltstack(struct thread * td,struct sigaltstack_args * uap)1634 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
1635 {
1636 stack_t ss, oss;
1637 int error;
1638
1639 if (uap->ss != NULL) {
1640 error = copyin(uap->ss, &ss, sizeof(ss));
1641 if (error)
1642 return (error);
1643 }
1644 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1645 (uap->oss != NULL) ? &oss : NULL);
1646 if (error)
1647 return (error);
1648 if (uap->oss != NULL)
1649 error = copyout(&oss, uap->oss, sizeof(stack_t));
1650 return (error);
1651 }
1652
1653 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1654 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1655 {
1656 struct proc *p = td->td_proc;
1657 int oonstack;
1658
1659 oonstack = sigonstack(cpu_getstack(td));
1660
1661 if (oss != NULL) {
1662 *oss = td->td_sigstk;
1663 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1664 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1665 }
1666
1667 if (ss != NULL) {
1668 if (oonstack)
1669 return (EPERM);
1670 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1671 return (EINVAL);
1672 if (!(ss->ss_flags & SS_DISABLE)) {
1673 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1674 return (ENOMEM);
1675
1676 td->td_sigstk = *ss;
1677 td->td_pflags |= TDP_ALTSTACK;
1678 } else {
1679 td->td_pflags &= ~TDP_ALTSTACK;
1680 }
1681 }
1682 return (0);
1683 }
1684
1685 /*
1686 * Common code for kill process group/broadcast kill.
1687 * cp is calling process.
1688 */
1689 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1690 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1691 {
1692 struct proc *p;
1693 struct pgrp *pgrp;
1694 int err;
1695 int ret;
1696
1697 ret = ESRCH;
1698 if (all) {
1699 /*
1700 * broadcast
1701 */
1702 sx_slock(&allproc_lock);
1703 FOREACH_PROC_IN_SYSTEM(p) {
1704 PROC_LOCK(p);
1705 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1706 p == td->td_proc || p->p_state == PRS_NEW) {
1707 PROC_UNLOCK(p);
1708 continue;
1709 }
1710 err = p_cansignal(td, p, sig);
1711 if (err == 0) {
1712 if (sig)
1713 pksignal(p, sig, ksi);
1714 ret = err;
1715 }
1716 else if (ret == ESRCH)
1717 ret = err;
1718 PROC_UNLOCK(p);
1719 }
1720 sx_sunlock(&allproc_lock);
1721 } else {
1722 sx_slock(&proctree_lock);
1723 if (pgid == 0) {
1724 /*
1725 * zero pgid means send to my process group.
1726 */
1727 pgrp = td->td_proc->p_pgrp;
1728 PGRP_LOCK(pgrp);
1729 } else {
1730 pgrp = pgfind(pgid);
1731 if (pgrp == NULL) {
1732 sx_sunlock(&proctree_lock);
1733 return (ESRCH);
1734 }
1735 }
1736 sx_sunlock(&proctree_lock);
1737 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1738 PROC_LOCK(p);
1739 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1740 p->p_state == PRS_NEW) {
1741 PROC_UNLOCK(p);
1742 continue;
1743 }
1744 err = p_cansignal(td, p, sig);
1745 if (err == 0) {
1746 if (sig)
1747 pksignal(p, sig, ksi);
1748 ret = err;
1749 }
1750 else if (ret == ESRCH)
1751 ret = err;
1752 PROC_UNLOCK(p);
1753 }
1754 PGRP_UNLOCK(pgrp);
1755 }
1756 return (ret);
1757 }
1758
1759 #ifndef _SYS_SYSPROTO_H_
1760 struct kill_args {
1761 int pid;
1762 int signum;
1763 };
1764 #endif
1765 /* ARGSUSED */
1766 int
sys_kill(struct thread * td,struct kill_args * uap)1767 sys_kill(struct thread *td, struct kill_args *uap)
1768 {
1769 ksiginfo_t ksi;
1770 struct proc *p;
1771 int error;
1772
1773 /*
1774 * A process in capability mode can send signals only to himself.
1775 * The main rationale behind this is that abort(3) is implemented as
1776 * kill(getpid(), SIGABRT).
1777 */
1778 if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid)
1779 return (ECAPMODE);
1780
1781 AUDIT_ARG_SIGNUM(uap->signum);
1782 AUDIT_ARG_PID(uap->pid);
1783 if ((u_int)uap->signum > _SIG_MAXSIG)
1784 return (EINVAL);
1785
1786 ksiginfo_init(&ksi);
1787 ksi.ksi_signo = uap->signum;
1788 ksi.ksi_code = SI_USER;
1789 ksi.ksi_pid = td->td_proc->p_pid;
1790 ksi.ksi_uid = td->td_ucred->cr_ruid;
1791
1792 if (uap->pid > 0) {
1793 /* kill single process */
1794 if ((p = pfind(uap->pid)) == NULL) {
1795 if ((p = zpfind(uap->pid)) == NULL)
1796 return (ESRCH);
1797 }
1798 AUDIT_ARG_PROCESS(p);
1799 error = p_cansignal(td, p, uap->signum);
1800 if (error == 0 && uap->signum)
1801 pksignal(p, uap->signum, &ksi);
1802 PROC_UNLOCK(p);
1803 return (error);
1804 }
1805 switch (uap->pid) {
1806 case -1: /* broadcast signal */
1807 return (killpg1(td, uap->signum, 0, 1, &ksi));
1808 case 0: /* signal own process group */
1809 return (killpg1(td, uap->signum, 0, 0, &ksi));
1810 default: /* negative explicit process group */
1811 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
1812 }
1813 /* NOTREACHED */
1814 }
1815
1816 int
sys_pdkill(struct thread * td,struct pdkill_args * uap)1817 sys_pdkill(struct thread *td, struct pdkill_args *uap)
1818 {
1819 struct proc *p;
1820 cap_rights_t rights;
1821 int error;
1822
1823 AUDIT_ARG_SIGNUM(uap->signum);
1824 AUDIT_ARG_FD(uap->fd);
1825 if ((u_int)uap->signum > _SIG_MAXSIG)
1826 return (EINVAL);
1827
1828 error = procdesc_find(td, uap->fd,
1829 cap_rights_init(&rights, CAP_PDKILL), &p);
1830 if (error)
1831 return (error);
1832 AUDIT_ARG_PROCESS(p);
1833 error = p_cansignal(td, p, uap->signum);
1834 if (error == 0 && uap->signum)
1835 kern_psignal(p, uap->signum);
1836 PROC_UNLOCK(p);
1837 return (error);
1838 }
1839
1840 #if defined(COMPAT_43)
1841 #ifndef _SYS_SYSPROTO_H_
1842 struct okillpg_args {
1843 int pgid;
1844 int signum;
1845 };
1846 #endif
1847 /* ARGSUSED */
1848 int
okillpg(struct thread * td,struct okillpg_args * uap)1849 okillpg(struct thread *td, struct okillpg_args *uap)
1850 {
1851 ksiginfo_t ksi;
1852
1853 AUDIT_ARG_SIGNUM(uap->signum);
1854 AUDIT_ARG_PID(uap->pgid);
1855 if ((u_int)uap->signum > _SIG_MAXSIG)
1856 return (EINVAL);
1857
1858 ksiginfo_init(&ksi);
1859 ksi.ksi_signo = uap->signum;
1860 ksi.ksi_code = SI_USER;
1861 ksi.ksi_pid = td->td_proc->p_pid;
1862 ksi.ksi_uid = td->td_ucred->cr_ruid;
1863 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
1864 }
1865 #endif /* COMPAT_43 */
1866
1867 #ifndef _SYS_SYSPROTO_H_
1868 struct sigqueue_args {
1869 pid_t pid;
1870 int signum;
1871 /* union sigval */ void *value;
1872 };
1873 #endif
1874 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)1875 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
1876 {
1877 union sigval sv;
1878
1879 sv.sival_ptr = uap->value;
1880
1881 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
1882 }
1883
1884 int
kern_sigqueue(struct thread * td,pid_t pid,int signum,union sigval * value)1885 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
1886 {
1887 ksiginfo_t ksi;
1888 struct proc *p;
1889 int error;
1890
1891 if ((u_int)signum > _SIG_MAXSIG)
1892 return (EINVAL);
1893
1894 /*
1895 * Specification says sigqueue can only send signal to
1896 * single process.
1897 */
1898 if (pid <= 0)
1899 return (EINVAL);
1900
1901 if ((p = pfind(pid)) == NULL) {
1902 if ((p = zpfind(pid)) == NULL)
1903 return (ESRCH);
1904 }
1905 error = p_cansignal(td, p, signum);
1906 if (error == 0 && signum != 0) {
1907 ksiginfo_init(&ksi);
1908 ksi.ksi_flags = KSI_SIGQ;
1909 ksi.ksi_signo = signum;
1910 ksi.ksi_code = SI_QUEUE;
1911 ksi.ksi_pid = td->td_proc->p_pid;
1912 ksi.ksi_uid = td->td_ucred->cr_ruid;
1913 ksi.ksi_value = *value;
1914 error = pksignal(p, ksi.ksi_signo, &ksi);
1915 }
1916 PROC_UNLOCK(p);
1917 return (error);
1918 }
1919
1920 /*
1921 * Send a signal to a process group.
1922 */
1923 void
gsignal(int pgid,int sig,ksiginfo_t * ksi)1924 gsignal(int pgid, int sig, ksiginfo_t *ksi)
1925 {
1926 struct pgrp *pgrp;
1927
1928 if (pgid != 0) {
1929 sx_slock(&proctree_lock);
1930 pgrp = pgfind(pgid);
1931 sx_sunlock(&proctree_lock);
1932 if (pgrp != NULL) {
1933 pgsignal(pgrp, sig, 0, ksi);
1934 PGRP_UNLOCK(pgrp);
1935 }
1936 }
1937 }
1938
1939 /*
1940 * Send a signal to a process group. If checktty is 1,
1941 * limit to members which have a controlling terminal.
1942 */
1943 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)1944 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
1945 {
1946 struct proc *p;
1947
1948 if (pgrp) {
1949 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
1950 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1951 PROC_LOCK(p);
1952 if (p->p_state == PRS_NORMAL &&
1953 (checkctty == 0 || p->p_flag & P_CONTROLT))
1954 pksignal(p, sig, ksi);
1955 PROC_UNLOCK(p);
1956 }
1957 }
1958 }
1959
1960
1961 /*
1962 * Recalculate the signal mask and reset the signal disposition after
1963 * usermode frame for delivery is formed. Should be called after
1964 * mach-specific routine, because sysent->sv_sendsig() needs correct
1965 * ps_siginfo and signal mask.
1966 */
1967 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)1968 postsig_done(int sig, struct thread *td, struct sigacts *ps)
1969 {
1970 sigset_t mask;
1971
1972 mtx_assert(&ps->ps_mtx, MA_OWNED);
1973 td->td_ru.ru_nsignals++;
1974 mask = ps->ps_catchmask[_SIG_IDX(sig)];
1975 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1976 SIGADDSET(mask, sig);
1977 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
1978 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
1979 if (SIGISMEMBER(ps->ps_sigreset, sig))
1980 sigdflt(ps, sig);
1981 }
1982
1983
1984 /*
1985 * Send a signal caused by a trap to the current thread. If it will be
1986 * caught immediately, deliver it with correct code. Otherwise, post it
1987 * normally.
1988 */
1989 void
trapsignal(struct thread * td,ksiginfo_t * ksi)1990 trapsignal(struct thread *td, ksiginfo_t *ksi)
1991 {
1992 struct sigacts *ps;
1993 struct proc *p;
1994 int sig;
1995 int code;
1996
1997 p = td->td_proc;
1998 sig = ksi->ksi_signo;
1999 code = ksi->ksi_code;
2000 KASSERT(_SIG_VALID(sig), ("invalid signal"));
2001
2002 PROC_LOCK(p);
2003 ps = p->p_sigacts;
2004 mtx_lock(&ps->ps_mtx);
2005 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
2006 !SIGISMEMBER(td->td_sigmask, sig)) {
2007 #ifdef KTRACE
2008 if (KTRPOINT(curthread, KTR_PSIG))
2009 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
2010 &td->td_sigmask, code);
2011 #endif
2012 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
2013 ksi, &td->td_sigmask);
2014 postsig_done(sig, td, ps);
2015 mtx_unlock(&ps->ps_mtx);
2016 } else {
2017 /*
2018 * Avoid a possible infinite loop if the thread
2019 * masking the signal or process is ignoring the
2020 * signal.
2021 */
2022 if (kern_forcesigexit &&
2023 (SIGISMEMBER(td->td_sigmask, sig) ||
2024 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
2025 SIGDELSET(td->td_sigmask, sig);
2026 SIGDELSET(ps->ps_sigcatch, sig);
2027 SIGDELSET(ps->ps_sigignore, sig);
2028 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2029 }
2030 mtx_unlock(&ps->ps_mtx);
2031 p->p_code = code; /* XXX for core dump/debugger */
2032 p->p_sig = sig; /* XXX to verify code */
2033 tdsendsignal(p, td, sig, ksi);
2034 }
2035 PROC_UNLOCK(p);
2036 }
2037
2038 static struct thread *
sigtd(struct proc * p,int sig,int prop)2039 sigtd(struct proc *p, int sig, int prop)
2040 {
2041 struct thread *td, *signal_td;
2042
2043 PROC_LOCK_ASSERT(p, MA_OWNED);
2044
2045 /*
2046 * Check if current thread can handle the signal without
2047 * switching context to another thread.
2048 */
2049 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
2050 return (curthread);
2051 signal_td = NULL;
2052 FOREACH_THREAD_IN_PROC(p, td) {
2053 if (!SIGISMEMBER(td->td_sigmask, sig)) {
2054 signal_td = td;
2055 break;
2056 }
2057 }
2058 if (signal_td == NULL)
2059 signal_td = FIRST_THREAD_IN_PROC(p);
2060 return (signal_td);
2061 }
2062
2063 /*
2064 * Send the signal to the process. If the signal has an action, the action
2065 * is usually performed by the target process rather than the caller; we add
2066 * the signal to the set of pending signals for the process.
2067 *
2068 * Exceptions:
2069 * o When a stop signal is sent to a sleeping process that takes the
2070 * default action, the process is stopped without awakening it.
2071 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2072 * regardless of the signal action (eg, blocked or ignored).
2073 *
2074 * Other ignored signals are discarded immediately.
2075 *
2076 * NB: This function may be entered from the debugger via the "kill" DDB
2077 * command. There is little that can be done to mitigate the possibly messy
2078 * side effects of this unwise possibility.
2079 */
2080 void
kern_psignal(struct proc * p,int sig)2081 kern_psignal(struct proc *p, int sig)
2082 {
2083 ksiginfo_t ksi;
2084
2085 ksiginfo_init(&ksi);
2086 ksi.ksi_signo = sig;
2087 ksi.ksi_code = SI_KERNEL;
2088 (void) tdsendsignal(p, NULL, sig, &ksi);
2089 }
2090
2091 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)2092 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2093 {
2094
2095 return (tdsendsignal(p, NULL, sig, ksi));
2096 }
2097
2098 /* Utility function for finding a thread to send signal event to. */
2099 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)2100 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
2101 {
2102 struct thread *td;
2103
2104 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2105 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2106 if (td == NULL)
2107 return (ESRCH);
2108 *ttd = td;
2109 } else {
2110 *ttd = NULL;
2111 PROC_LOCK(p);
2112 }
2113 return (0);
2114 }
2115
2116 void
tdsignal(struct thread * td,int sig)2117 tdsignal(struct thread *td, int sig)
2118 {
2119 ksiginfo_t ksi;
2120
2121 ksiginfo_init(&ksi);
2122 ksi.ksi_signo = sig;
2123 ksi.ksi_code = SI_KERNEL;
2124 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2125 }
2126
2127 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2128 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2129 {
2130
2131 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2132 }
2133
2134 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2135 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2136 {
2137 sig_t action;
2138 sigqueue_t *sigqueue;
2139 int prop;
2140 struct sigacts *ps;
2141 int intrval;
2142 int ret = 0;
2143 int wakeup_swapper;
2144
2145 MPASS(td == NULL || p == td->td_proc);
2146 PROC_LOCK_ASSERT(p, MA_OWNED);
2147
2148 if (!_SIG_VALID(sig))
2149 panic("%s(): invalid signal %d", __func__, sig);
2150
2151 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2152
2153 /*
2154 * IEEE Std 1003.1-2001: return success when killing a zombie.
2155 */
2156 if (p->p_state == PRS_ZOMBIE) {
2157 if (ksi && (ksi->ksi_flags & KSI_INS))
2158 ksiginfo_tryfree(ksi);
2159 return (ret);
2160 }
2161
2162 ps = p->p_sigacts;
2163 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
2164 prop = sigprop(sig);
2165
2166 if (td == NULL) {
2167 td = sigtd(p, sig, prop);
2168 sigqueue = &p->p_sigqueue;
2169 } else
2170 sigqueue = &td->td_sigqueue;
2171
2172 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2173
2174 /*
2175 * If the signal is being ignored,
2176 * then we forget about it immediately.
2177 * (Note: we don't set SIGCONT in ps_sigignore,
2178 * and if it is set to SIG_IGN,
2179 * action will be SIG_DFL here.)
2180 */
2181 mtx_lock(&ps->ps_mtx);
2182 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2183 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2184
2185 mtx_unlock(&ps->ps_mtx);
2186 if (ksi && (ksi->ksi_flags & KSI_INS))
2187 ksiginfo_tryfree(ksi);
2188 return (ret);
2189 }
2190 if (SIGISMEMBER(td->td_sigmask, sig))
2191 action = SIG_HOLD;
2192 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2193 action = SIG_CATCH;
2194 else
2195 action = SIG_DFL;
2196 if (SIGISMEMBER(ps->ps_sigintr, sig))
2197 intrval = EINTR;
2198 else
2199 intrval = ERESTART;
2200 mtx_unlock(&ps->ps_mtx);
2201
2202 if (prop & SA_CONT)
2203 sigqueue_delete_stopmask_proc(p);
2204 else if (prop & SA_STOP) {
2205 /*
2206 * If sending a tty stop signal to a member of an orphaned
2207 * process group, discard the signal here if the action
2208 * is default; don't stop the process below if sleeping,
2209 * and don't clear any pending SIGCONT.
2210 */
2211 if ((prop & SA_TTYSTOP) &&
2212 (p->p_pgrp->pg_jobc == 0) &&
2213 (action == SIG_DFL)) {
2214 if (ksi && (ksi->ksi_flags & KSI_INS))
2215 ksiginfo_tryfree(ksi);
2216 return (ret);
2217 }
2218 sigqueue_delete_proc(p, SIGCONT);
2219 if (p->p_flag & P_CONTINUED) {
2220 p->p_flag &= ~P_CONTINUED;
2221 PROC_LOCK(p->p_pptr);
2222 sigqueue_take(p->p_ksi);
2223 PROC_UNLOCK(p->p_pptr);
2224 }
2225 }
2226
2227 ret = sigqueue_add(sigqueue, sig, ksi);
2228 if (ret != 0)
2229 return (ret);
2230 signotify(td);
2231 /*
2232 * Defer further processing for signals which are held,
2233 * except that stopped processes must be continued by SIGCONT.
2234 */
2235 if (action == SIG_HOLD &&
2236 !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
2237 return (ret);
2238
2239 /* SIGKILL: Remove procfs STOPEVENTs. */
2240 if (sig == SIGKILL) {
2241 /* from procfs_ioctl.c: PIOCBIC */
2242 p->p_stops = 0;
2243 /* from procfs_ioctl.c: PIOCCONT */
2244 p->p_step = 0;
2245 wakeup(&p->p_step);
2246 }
2247 /*
2248 * Some signals have a process-wide effect and a per-thread
2249 * component. Most processing occurs when the process next
2250 * tries to cross the user boundary, however there are some
2251 * times when processing needs to be done immediately, such as
2252 * waking up threads so that they can cross the user boundary.
2253 * We try to do the per-process part here.
2254 */
2255 if (P_SHOULDSTOP(p)) {
2256 KASSERT(!(p->p_flag & P_WEXIT),
2257 ("signal to stopped but exiting process"));
2258 if (sig == SIGKILL) {
2259 /*
2260 * If traced process is already stopped,
2261 * then no further action is necessary.
2262 */
2263 if (p->p_flag & P_TRACED)
2264 goto out;
2265 /*
2266 * SIGKILL sets process running.
2267 * It will die elsewhere.
2268 * All threads must be restarted.
2269 */
2270 p->p_flag &= ~P_STOPPED_SIG;
2271 goto runfast;
2272 }
2273
2274 if (prop & SA_CONT) {
2275 /*
2276 * If traced process is already stopped,
2277 * then no further action is necessary.
2278 */
2279 if (p->p_flag & P_TRACED)
2280 goto out;
2281 /*
2282 * If SIGCONT is default (or ignored), we continue the
2283 * process but don't leave the signal in sigqueue as
2284 * it has no further action. If SIGCONT is held, we
2285 * continue the process and leave the signal in
2286 * sigqueue. If the process catches SIGCONT, let it
2287 * handle the signal itself. If it isn't waiting on
2288 * an event, it goes back to run state.
2289 * Otherwise, process goes back to sleep state.
2290 */
2291 p->p_flag &= ~P_STOPPED_SIG;
2292 PROC_SLOCK(p);
2293 if (p->p_numthreads == p->p_suspcount) {
2294 PROC_SUNLOCK(p);
2295 p->p_flag |= P_CONTINUED;
2296 p->p_xsig = SIGCONT;
2297 PROC_LOCK(p->p_pptr);
2298 childproc_continued(p);
2299 PROC_UNLOCK(p->p_pptr);
2300 PROC_SLOCK(p);
2301 }
2302 if (action == SIG_DFL) {
2303 thread_unsuspend(p);
2304 PROC_SUNLOCK(p);
2305 sigqueue_delete(sigqueue, sig);
2306 goto out;
2307 }
2308 if (action == SIG_CATCH) {
2309 /*
2310 * The process wants to catch it so it needs
2311 * to run at least one thread, but which one?
2312 */
2313 PROC_SUNLOCK(p);
2314 goto runfast;
2315 }
2316 /*
2317 * The signal is not ignored or caught.
2318 */
2319 thread_unsuspend(p);
2320 PROC_SUNLOCK(p);
2321 goto out;
2322 }
2323
2324 if (prop & SA_STOP) {
2325 /*
2326 * If traced process is already stopped,
2327 * then no further action is necessary.
2328 */
2329 if (p->p_flag & P_TRACED)
2330 goto out;
2331 /*
2332 * Already stopped, don't need to stop again
2333 * (If we did the shell could get confused).
2334 * Just make sure the signal STOP bit set.
2335 */
2336 p->p_flag |= P_STOPPED_SIG;
2337 sigqueue_delete(sigqueue, sig);
2338 goto out;
2339 }
2340
2341 /*
2342 * All other kinds of signals:
2343 * If a thread is sleeping interruptibly, simulate a
2344 * wakeup so that when it is continued it will be made
2345 * runnable and can look at the signal. However, don't make
2346 * the PROCESS runnable, leave it stopped.
2347 * It may run a bit until it hits a thread_suspend_check().
2348 */
2349 wakeup_swapper = 0;
2350 PROC_SLOCK(p);
2351 thread_lock(td);
2352 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
2353 wakeup_swapper = sleepq_abort(td, intrval);
2354 thread_unlock(td);
2355 PROC_SUNLOCK(p);
2356 if (wakeup_swapper)
2357 kick_proc0();
2358 goto out;
2359 /*
2360 * Mutexes are short lived. Threads waiting on them will
2361 * hit thread_suspend_check() soon.
2362 */
2363 } else if (p->p_state == PRS_NORMAL) {
2364 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2365 tdsigwakeup(td, sig, action, intrval);
2366 goto out;
2367 }
2368
2369 MPASS(action == SIG_DFL);
2370
2371 if (prop & SA_STOP) {
2372 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2373 goto out;
2374 p->p_flag |= P_STOPPED_SIG;
2375 p->p_xsig = sig;
2376 PROC_SLOCK(p);
2377 wakeup_swapper = sig_suspend_threads(td, p, 1);
2378 if (p->p_numthreads == p->p_suspcount) {
2379 /*
2380 * only thread sending signal to another
2381 * process can reach here, if thread is sending
2382 * signal to its process, because thread does
2383 * not suspend itself here, p_numthreads
2384 * should never be equal to p_suspcount.
2385 */
2386 thread_stopped(p);
2387 PROC_SUNLOCK(p);
2388 sigqueue_delete_proc(p, p->p_xsig);
2389 } else
2390 PROC_SUNLOCK(p);
2391 if (wakeup_swapper)
2392 kick_proc0();
2393 goto out;
2394 }
2395 } else {
2396 /* Not in "NORMAL" state. discard the signal. */
2397 sigqueue_delete(sigqueue, sig);
2398 goto out;
2399 }
2400
2401 /*
2402 * The process is not stopped so we need to apply the signal to all the
2403 * running threads.
2404 */
2405 runfast:
2406 tdsigwakeup(td, sig, action, intrval);
2407 PROC_SLOCK(p);
2408 thread_unsuspend(p);
2409 PROC_SUNLOCK(p);
2410 out:
2411 /* If we jump here, proc slock should not be owned. */
2412 PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
2413 return (ret);
2414 }
2415
2416 /*
2417 * The force of a signal has been directed against a single
2418 * thread. We need to see what we can do about knocking it
2419 * out of any sleep it may be in etc.
2420 */
2421 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2422 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2423 {
2424 struct proc *p = td->td_proc;
2425 int prop;
2426 int wakeup_swapper;
2427
2428 wakeup_swapper = 0;
2429 PROC_LOCK_ASSERT(p, MA_OWNED);
2430 prop = sigprop(sig);
2431
2432 PROC_SLOCK(p);
2433 thread_lock(td);
2434 /*
2435 * Bring the priority of a thread up if we want it to get
2436 * killed in this lifetime. Be careful to avoid bumping the
2437 * priority of the idle thread, since we still allow to signal
2438 * kernel processes.
2439 */
2440 if (action == SIG_DFL && (prop & SA_KILL) != 0 &&
2441 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2442 sched_prio(td, PUSER);
2443 if (TD_ON_SLEEPQ(td)) {
2444 /*
2445 * If thread is sleeping uninterruptibly
2446 * we can't interrupt the sleep... the signal will
2447 * be noticed when the process returns through
2448 * trap() or syscall().
2449 */
2450 if ((td->td_flags & TDF_SINTR) == 0)
2451 goto out;
2452 /*
2453 * If SIGCONT is default (or ignored) and process is
2454 * asleep, we are finished; the process should not
2455 * be awakened.
2456 */
2457 if ((prop & SA_CONT) && action == SIG_DFL) {
2458 thread_unlock(td);
2459 PROC_SUNLOCK(p);
2460 sigqueue_delete(&p->p_sigqueue, sig);
2461 /*
2462 * It may be on either list in this state.
2463 * Remove from both for now.
2464 */
2465 sigqueue_delete(&td->td_sigqueue, sig);
2466 return;
2467 }
2468
2469 /*
2470 * Don't awaken a sleeping thread for SIGSTOP if the
2471 * STOP signal is deferred.
2472 */
2473 if ((prop & SA_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2474 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2475 goto out;
2476
2477 /*
2478 * Give low priority threads a better chance to run.
2479 */
2480 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2481 sched_prio(td, PUSER);
2482
2483 wakeup_swapper = sleepq_abort(td, intrval);
2484 } else {
2485 /*
2486 * Other states do nothing with the signal immediately,
2487 * other than kicking ourselves if we are running.
2488 * It will either never be noticed, or noticed very soon.
2489 */
2490 #ifdef SMP
2491 if (TD_IS_RUNNING(td) && td != curthread)
2492 forward_signal(td);
2493 #endif
2494 }
2495 out:
2496 PROC_SUNLOCK(p);
2497 thread_unlock(td);
2498 if (wakeup_swapper)
2499 kick_proc0();
2500 }
2501
2502 static int
sig_suspend_threads(struct thread * td,struct proc * p,int sending)2503 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
2504 {
2505 struct thread *td2;
2506 int wakeup_swapper;
2507
2508 PROC_LOCK_ASSERT(p, MA_OWNED);
2509 PROC_SLOCK_ASSERT(p, MA_OWNED);
2510 MPASS(sending || td == curthread);
2511
2512 wakeup_swapper = 0;
2513 FOREACH_THREAD_IN_PROC(p, td2) {
2514 thread_lock(td2);
2515 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
2516 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
2517 (td2->td_flags & TDF_SINTR)) {
2518 if (td2->td_flags & TDF_SBDRY) {
2519 /*
2520 * Once a thread is asleep with
2521 * TDF_SBDRY and without TDF_SERESTART
2522 * or TDF_SEINTR set, it should never
2523 * become suspended due to this check.
2524 */
2525 KASSERT(!TD_IS_SUSPENDED(td2),
2526 ("thread with deferred stops suspended"));
2527 if (TD_SBDRY_INTR(td2))
2528 wakeup_swapper |= sleepq_abort(td2,
2529 TD_SBDRY_ERRNO(td2));
2530 } else if (!TD_IS_SUSPENDED(td2)) {
2531 thread_suspend_one(td2);
2532 }
2533 } else if (!TD_IS_SUSPENDED(td2)) {
2534 if (sending || td != td2)
2535 td2->td_flags |= TDF_ASTPENDING;
2536 #ifdef SMP
2537 if (TD_IS_RUNNING(td2) && td2 != td)
2538 forward_signal(td2);
2539 #endif
2540 }
2541 thread_unlock(td2);
2542 }
2543 return (wakeup_swapper);
2544 }
2545
2546 /*
2547 * Stop the process for an event deemed interesting to the debugger. If si is
2548 * non-NULL, this is a signal exchange; the new signal requested by the
2549 * debugger will be returned for handling. If si is NULL, this is some other
2550 * type of interesting event. The debugger may request a signal be delivered in
2551 * that case as well, however it will be deferred until it can be handled.
2552 */
2553 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2554 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2555 {
2556 struct proc *p = td->td_proc;
2557 struct thread *td2;
2558 ksiginfo_t ksi;
2559 int prop;
2560
2561 PROC_LOCK_ASSERT(p, MA_OWNED);
2562 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2563 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2564 &p->p_mtx.lock_object, "Stopping for traced signal");
2565
2566 td->td_xsig = sig;
2567
2568 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2569 td->td_dbgflags |= TDB_XSIG;
2570 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2571 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2572 PROC_SLOCK(p);
2573 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2574 if (P_KILLED(p)) {
2575 /*
2576 * Ensure that, if we've been PT_KILLed, the
2577 * exit status reflects that. Another thread
2578 * may also be in ptracestop(), having just
2579 * received the SIGKILL, but this thread was
2580 * unsuspended first.
2581 */
2582 td->td_dbgflags &= ~TDB_XSIG;
2583 td->td_xsig = SIGKILL;
2584 p->p_ptevents = 0;
2585 break;
2586 }
2587 if (p->p_flag & P_SINGLE_EXIT &&
2588 !(td->td_dbgflags & TDB_EXIT)) {
2589 /*
2590 * Ignore ptrace stops except for thread exit
2591 * events when the process exits.
2592 */
2593 td->td_dbgflags &= ~TDB_XSIG;
2594 PROC_SUNLOCK(p);
2595 return (0);
2596 }
2597
2598 /*
2599 * Make wait(2) work. Ensure that right after the
2600 * attach, the thread which was decided to become the
2601 * leader of attach gets reported to the waiter.
2602 * Otherwise, just avoid overwriting another thread's
2603 * assignment to p_xthread. If another thread has
2604 * already set p_xthread, the current thread will get
2605 * a chance to report itself upon the next iteration.
2606 */
2607 if ((td->td_dbgflags & TDB_FSTP) != 0 ||
2608 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
2609 p->p_xthread == NULL)) {
2610 p->p_xsig = sig;
2611 p->p_xthread = td;
2612
2613 /*
2614 * If we are on sleepqueue already,
2615 * let sleepqueue code decide if it
2616 * needs to go sleep after attach.
2617 */
2618 if (td->td_wchan == NULL)
2619 td->td_dbgflags &= ~TDB_FSTP;
2620
2621 p->p_flag2 &= ~P2_PTRACE_FSTP;
2622 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2623 sig_suspend_threads(td, p, 0);
2624 }
2625 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2626 td->td_dbgflags &= ~TDB_STOPATFORK;
2627 }
2628 stopme:
2629 thread_suspend_switch(td, p);
2630 if (p->p_xthread == td)
2631 p->p_xthread = NULL;
2632 if (!(p->p_flag & P_TRACED))
2633 break;
2634 if (td->td_dbgflags & TDB_SUSPEND) {
2635 if (p->p_flag & P_SINGLE_EXIT)
2636 break;
2637 goto stopme;
2638 }
2639 }
2640 PROC_SUNLOCK(p);
2641 }
2642
2643 if (si != NULL && sig == td->td_xsig) {
2644 /* Parent wants us to take the original signal unchanged. */
2645 si->ksi_flags |= KSI_HEAD;
2646 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2647 si->ksi_signo = 0;
2648 } else if (td->td_xsig != 0) {
2649 /*
2650 * If parent wants us to take a new signal, then it will leave
2651 * it in td->td_xsig; otherwise we just look for signals again.
2652 */
2653 ksiginfo_init(&ksi);
2654 ksi.ksi_signo = td->td_xsig;
2655 ksi.ksi_flags |= KSI_PTRACE;
2656 prop = sigprop(td->td_xsig);
2657 td2 = sigtd(p, td->td_xsig, prop);
2658 tdsendsignal(p, td2, td->td_xsig, &ksi);
2659 if (td != td2)
2660 return (0);
2661 }
2662
2663 return (td->td_xsig);
2664 }
2665
2666 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2667 reschedule_signals(struct proc *p, sigset_t block, int flags)
2668 {
2669 struct sigacts *ps;
2670 struct thread *td;
2671 int sig;
2672
2673 PROC_LOCK_ASSERT(p, MA_OWNED);
2674 ps = p->p_sigacts;
2675 mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ?
2676 MA_OWNED : MA_NOTOWNED);
2677 if (SIGISEMPTY(p->p_siglist))
2678 return;
2679 SIGSETAND(block, p->p_siglist);
2680 while ((sig = sig_ffs(&block)) != 0) {
2681 SIGDELSET(block, sig);
2682 td = sigtd(p, sig, 0);
2683 signotify(td);
2684 if (!(flags & SIGPROCMASK_PS_LOCKED))
2685 mtx_lock(&ps->ps_mtx);
2686 if (p->p_flag & P_TRACED ||
2687 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
2688 !SIGISMEMBER(td->td_sigmask, sig)))
2689 tdsigwakeup(td, sig, SIG_CATCH,
2690 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
2691 ERESTART));
2692 if (!(flags & SIGPROCMASK_PS_LOCKED))
2693 mtx_unlock(&ps->ps_mtx);
2694 }
2695 }
2696
2697 void
tdsigcleanup(struct thread * td)2698 tdsigcleanup(struct thread *td)
2699 {
2700 struct proc *p;
2701 sigset_t unblocked;
2702
2703 p = td->td_proc;
2704 PROC_LOCK_ASSERT(p, MA_OWNED);
2705
2706 sigqueue_flush(&td->td_sigqueue);
2707 if (p->p_numthreads == 1)
2708 return;
2709
2710 /*
2711 * Since we cannot handle signals, notify signal post code
2712 * about this by filling the sigmask.
2713 *
2714 * Also, if needed, wake up thread(s) that do not block the
2715 * same signals as the exiting thread, since the thread might
2716 * have been selected for delivery and woken up.
2717 */
2718 SIGFILLSET(unblocked);
2719 SIGSETNAND(unblocked, td->td_sigmask);
2720 SIGFILLSET(td->td_sigmask);
2721 reschedule_signals(p, unblocked, 0);
2722
2723 }
2724
2725 static int
sigdeferstop_curr_flags(int cflags)2726 sigdeferstop_curr_flags(int cflags)
2727 {
2728
2729 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
2730 (cflags & TDF_SBDRY) != 0);
2731 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
2732 }
2733
2734 /*
2735 * Defer the delivery of SIGSTOP for the current thread, according to
2736 * the requested mode. Returns previous flags, which must be restored
2737 * by sigallowstop().
2738 *
2739 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
2740 * cleared by the current thread, which allow the lock-less read-only
2741 * accesses below.
2742 */
2743 int
sigdeferstop_impl(int mode)2744 sigdeferstop_impl(int mode)
2745 {
2746 struct thread *td;
2747 int cflags, nflags;
2748
2749 td = curthread;
2750 cflags = sigdeferstop_curr_flags(td->td_flags);
2751 switch (mode) {
2752 case SIGDEFERSTOP_NOP:
2753 nflags = cflags;
2754 break;
2755 case SIGDEFERSTOP_OFF:
2756 nflags = 0;
2757 break;
2758 case SIGDEFERSTOP_SILENT:
2759 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
2760 break;
2761 case SIGDEFERSTOP_EINTR:
2762 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
2763 break;
2764 case SIGDEFERSTOP_ERESTART:
2765 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
2766 break;
2767 default:
2768 panic("sigdeferstop: invalid mode %x", mode);
2769 break;
2770 }
2771 if (cflags == nflags)
2772 return (SIGDEFERSTOP_VAL_NCHG);
2773 thread_lock(td);
2774 td->td_flags = (td->td_flags & ~cflags) | nflags;
2775 thread_unlock(td);
2776 return (cflags);
2777 }
2778
2779 /*
2780 * Restores the STOP handling mode, typically permitting the delivery
2781 * of SIGSTOP for the current thread. This does not immediately
2782 * suspend if a stop was posted. Instead, the thread will suspend
2783 * either via ast() or a subsequent interruptible sleep.
2784 */
2785 void
sigallowstop_impl(int prev)2786 sigallowstop_impl(int prev)
2787 {
2788 struct thread *td;
2789 int cflags;
2790
2791 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
2792 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
2793 ("sigallowstop: incorrect previous mode %x", prev));
2794 td = curthread;
2795 cflags = sigdeferstop_curr_flags(td->td_flags);
2796 if (cflags != prev) {
2797 thread_lock(td);
2798 td->td_flags = (td->td_flags & ~cflags) | prev;
2799 thread_unlock(td);
2800 }
2801 }
2802
2803 /*
2804 * If the current process has received a signal (should be caught or cause
2805 * termination, should interrupt current syscall), return the signal number.
2806 * Stop signals with default action are processed immediately, then cleared;
2807 * they aren't returned. This is checked after each entry to the system for
2808 * a syscall or trap (though this can usually be done without calling issignal
2809 * by checking the pending signal masks in cursig.) The normal call
2810 * sequence is
2811 *
2812 * while (sig = cursig(curthread))
2813 * postsig(sig);
2814 */
2815 static int
issignal(struct thread * td)2816 issignal(struct thread *td)
2817 {
2818 struct proc *p;
2819 struct sigacts *ps;
2820 struct sigqueue *queue;
2821 sigset_t sigpending;
2822 int prop, sig, traced;
2823 ksiginfo_t ksi;
2824
2825 p = td->td_proc;
2826 ps = p->p_sigacts;
2827 mtx_assert(&ps->ps_mtx, MA_OWNED);
2828 PROC_LOCK_ASSERT(p, MA_OWNED);
2829 for (;;) {
2830 traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
2831
2832 sigpending = td->td_sigqueue.sq_signals;
2833 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
2834 SIGSETNAND(sigpending, td->td_sigmask);
2835
2836 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
2837 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2838 SIG_STOPSIGMASK(sigpending);
2839 if (SIGISEMPTY(sigpending)) /* no signal to send */
2840 return (0);
2841 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
2842 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
2843 SIGISMEMBER(sigpending, SIGSTOP)) {
2844 /*
2845 * If debugger just attached, always consume
2846 * SIGSTOP from ptrace(PT_ATTACH) first, to
2847 * execute the debugger attach ritual in
2848 * order.
2849 */
2850 sig = SIGSTOP;
2851 td->td_dbgflags |= TDB_FSTP;
2852 } else {
2853 sig = sig_ffs(&sigpending);
2854 }
2855
2856 if (p->p_stops & S_SIG) {
2857 mtx_unlock(&ps->ps_mtx);
2858 stopevent(p, S_SIG, sig);
2859 mtx_lock(&ps->ps_mtx);
2860 }
2861
2862 /*
2863 * We should see pending but ignored signals
2864 * only if P_TRACED was on when they were posted.
2865 */
2866 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
2867 sigqueue_delete(&td->td_sigqueue, sig);
2868 sigqueue_delete(&p->p_sigqueue, sig);
2869 continue;
2870 }
2871 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
2872 /*
2873 * If traced, always stop.
2874 * Remove old signal from queue before the stop.
2875 * XXX shrug off debugger, it causes siginfo to
2876 * be thrown away.
2877 */
2878 queue = &td->td_sigqueue;
2879 ksiginfo_init(&ksi);
2880 if (sigqueue_get(queue, sig, &ksi) == 0) {
2881 queue = &p->p_sigqueue;
2882 sigqueue_get(queue, sig, &ksi);
2883 }
2884 td->td_si = ksi.ksi_info;
2885
2886 mtx_unlock(&ps->ps_mtx);
2887 sig = ptracestop(td, sig, &ksi);
2888 mtx_lock(&ps->ps_mtx);
2889
2890 td->td_si.si_signo = 0;
2891
2892 /*
2893 * Keep looking if the debugger discarded or
2894 * replaced the signal.
2895 */
2896 if (sig == 0)
2897 continue;
2898
2899 /*
2900 * If the signal became masked, re-queue it.
2901 */
2902 if (SIGISMEMBER(td->td_sigmask, sig)) {
2903 ksi.ksi_flags |= KSI_HEAD;
2904 sigqueue_add(&p->p_sigqueue, sig, &ksi);
2905 continue;
2906 }
2907
2908 /*
2909 * If the traced bit got turned off, requeue
2910 * the signal and go back up to the top to
2911 * rescan signals. This ensures that p_sig*
2912 * and p_sigact are consistent.
2913 */
2914 if ((p->p_flag & P_TRACED) == 0) {
2915 ksi.ksi_flags |= KSI_HEAD;
2916 sigqueue_add(queue, sig, &ksi);
2917 continue;
2918 }
2919 }
2920
2921 prop = sigprop(sig);
2922
2923 /*
2924 * Decide whether the signal should be returned.
2925 * Return the signal's number, or fall through
2926 * to clear it from the pending mask.
2927 */
2928 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2929
2930 case (intptr_t)SIG_DFL:
2931 /*
2932 * Don't take default actions on system processes.
2933 */
2934 if (p->p_pid <= 1) {
2935 #ifdef DIAGNOSTIC
2936 /*
2937 * Are you sure you want to ignore SIGSEGV
2938 * in init? XXX
2939 */
2940 printf("Process (pid %lu) got signal %d\n",
2941 (u_long)p->p_pid, sig);
2942 #endif
2943 break; /* == ignore */
2944 }
2945 /*
2946 * If there is a pending stop signal to process with
2947 * default action, stop here, then clear the signal.
2948 * Traced or exiting processes should ignore stops.
2949 * Additionally, a member of an orphaned process group
2950 * should ignore tty stops.
2951 */
2952 if (prop & SA_STOP) {
2953 if (p->p_flag &
2954 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) ||
2955 (p->p_pgrp->pg_jobc == 0 &&
2956 prop & SA_TTYSTOP))
2957 break; /* == ignore */
2958 if (TD_SBDRY_INTR(td)) {
2959 KASSERT((td->td_flags & TDF_SBDRY) != 0,
2960 ("lost TDF_SBDRY"));
2961 return (-1);
2962 }
2963 mtx_unlock(&ps->ps_mtx);
2964 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2965 &p->p_mtx.lock_object, "Catching SIGSTOP");
2966 sigqueue_delete(&td->td_sigqueue, sig);
2967 sigqueue_delete(&p->p_sigqueue, sig);
2968 p->p_flag |= P_STOPPED_SIG;
2969 p->p_xsig = sig;
2970 PROC_SLOCK(p);
2971 sig_suspend_threads(td, p, 0);
2972 thread_suspend_switch(td, p);
2973 PROC_SUNLOCK(p);
2974 mtx_lock(&ps->ps_mtx);
2975 goto next;
2976 } else if (prop & SA_IGNORE) {
2977 /*
2978 * Except for SIGCONT, shouldn't get here.
2979 * Default action is to ignore; drop it.
2980 */
2981 break; /* == ignore */
2982 } else
2983 return (sig);
2984 /*NOTREACHED*/
2985
2986 case (intptr_t)SIG_IGN:
2987 /*
2988 * Masking above should prevent us ever trying
2989 * to take action on an ignored signal other
2990 * than SIGCONT, unless process is traced.
2991 */
2992 if ((prop & SA_CONT) == 0 &&
2993 (p->p_flag & P_TRACED) == 0)
2994 printf("issignal\n");
2995 break; /* == ignore */
2996
2997 default:
2998 /*
2999 * This signal has an action, let
3000 * postsig() process it.
3001 */
3002 return (sig);
3003 }
3004 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
3005 sigqueue_delete(&p->p_sigqueue, sig);
3006 next:;
3007 }
3008 /* NOTREACHED */
3009 }
3010
3011 void
thread_stopped(struct proc * p)3012 thread_stopped(struct proc *p)
3013 {
3014 int n;
3015
3016 PROC_LOCK_ASSERT(p, MA_OWNED);
3017 PROC_SLOCK_ASSERT(p, MA_OWNED);
3018 n = p->p_suspcount;
3019 if (p == curproc)
3020 n++;
3021 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
3022 PROC_SUNLOCK(p);
3023 p->p_flag &= ~P_WAITED;
3024 PROC_LOCK(p->p_pptr);
3025 childproc_stopped(p, (p->p_flag & P_TRACED) ?
3026 CLD_TRAPPED : CLD_STOPPED);
3027 PROC_UNLOCK(p->p_pptr);
3028 PROC_SLOCK(p);
3029 }
3030 }
3031
3032 /*
3033 * Take the action for the specified signal
3034 * from the current set of pending signals.
3035 */
3036 int
postsig(int sig)3037 postsig(int sig)
3038 {
3039 struct thread *td;
3040 struct proc *p;
3041 struct sigacts *ps;
3042 sig_t action;
3043 ksiginfo_t ksi;
3044 sigset_t returnmask;
3045
3046 KASSERT(sig != 0, ("postsig"));
3047
3048 td = curthread;
3049 p = td->td_proc;
3050 PROC_LOCK_ASSERT(p, MA_OWNED);
3051 ps = p->p_sigacts;
3052 mtx_assert(&ps->ps_mtx, MA_OWNED);
3053 ksiginfo_init(&ksi);
3054 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3055 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3056 return (0);
3057 ksi.ksi_signo = sig;
3058 if (ksi.ksi_code == SI_TIMER)
3059 itimer_accept(p, ksi.ksi_timerid, &ksi);
3060 action = ps->ps_sigact[_SIG_IDX(sig)];
3061 #ifdef KTRACE
3062 if (KTRPOINT(td, KTR_PSIG))
3063 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3064 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3065 #endif
3066 if ((p->p_stops & S_SIG) != 0) {
3067 mtx_unlock(&ps->ps_mtx);
3068 stopevent(p, S_SIG, sig);
3069 mtx_lock(&ps->ps_mtx);
3070 }
3071
3072 if (action == SIG_DFL) {
3073 /*
3074 * Default action, where the default is to kill
3075 * the process. (Other cases were ignored above.)
3076 */
3077 mtx_unlock(&ps->ps_mtx);
3078 proc_td_siginfo_capture(td, &ksi.ksi_info);
3079 sigexit(td, sig);
3080 /* NOTREACHED */
3081 } else {
3082 /*
3083 * If we get here, the signal must be caught.
3084 */
3085 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3086 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3087 ("postsig action: blocked sig %d", sig));
3088
3089 /*
3090 * Set the new mask value and also defer further
3091 * occurrences of this signal.
3092 *
3093 * Special case: user has done a sigsuspend. Here the
3094 * current mask is not of interest, but rather the
3095 * mask from before the sigsuspend is what we want
3096 * restored after the signal processing is completed.
3097 */
3098 if (td->td_pflags & TDP_OLDMASK) {
3099 returnmask = td->td_oldsigmask;
3100 td->td_pflags &= ~TDP_OLDMASK;
3101 } else
3102 returnmask = td->td_sigmask;
3103
3104 if (p->p_sig == sig) {
3105 p->p_code = 0;
3106 p->p_sig = 0;
3107 }
3108 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3109 postsig_done(sig, td, ps);
3110 }
3111 return (1);
3112 }
3113
3114 void
proc_wkilled(struct proc * p)3115 proc_wkilled(struct proc *p)
3116 {
3117
3118 PROC_LOCK_ASSERT(p, MA_OWNED);
3119 if ((p->p_flag & P_WKILLED) == 0) {
3120 p->p_flag |= P_WKILLED;
3121 /*
3122 * Notify swapper that there is a process to swap in.
3123 * The notification is racy, at worst it would take 10
3124 * seconds for the swapper process to notice.
3125 */
3126 if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0)
3127 wakeup(&proc0);
3128 }
3129 }
3130
3131 /*
3132 * Kill the current process for stated reason.
3133 */
3134 void
killproc(struct proc * p,char * why)3135 killproc(struct proc *p, char *why)
3136 {
3137
3138 PROC_LOCK_ASSERT(p, MA_OWNED);
3139 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3140 p->p_comm);
3141 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
3142 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
3143 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
3144 proc_wkilled(p);
3145 kern_psignal(p, SIGKILL);
3146 }
3147
3148 /*
3149 * Force the current process to exit with the specified signal, dumping core
3150 * if appropriate. We bypass the normal tests for masked and caught signals,
3151 * allowing unrecoverable failures to terminate the process without changing
3152 * signal state. Mark the accounting record with the signal termination.
3153 * If dumping core, save the signal number for the debugger. Calls exit and
3154 * does not return.
3155 */
3156 void
sigexit(struct thread * td,int sig)3157 sigexit(struct thread *td, int sig)
3158 {
3159 struct proc *p = td->td_proc;
3160
3161 PROC_LOCK_ASSERT(p, MA_OWNED);
3162 p->p_acflag |= AXSIG;
3163 /*
3164 * We must be single-threading to generate a core dump. This
3165 * ensures that the registers in the core file are up-to-date.
3166 * Also, the ELF dump handler assumes that the thread list doesn't
3167 * change out from under it.
3168 *
3169 * XXX If another thread attempts to single-thread before us
3170 * (e.g. via fork()), we won't get a dump at all.
3171 */
3172 if ((sigprop(sig) & SA_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) {
3173 p->p_sig = sig;
3174 /*
3175 * Log signals which would cause core dumps
3176 * (Log as LOG_INFO to appease those who don't want
3177 * these messages.)
3178 * XXX : Todo, as well as euid, write out ruid too
3179 * Note that coredump() drops proc lock.
3180 */
3181 if (coredump(td) == 0)
3182 sig |= WCOREFLAG;
3183 if (kern_logsigexit)
3184 log(LOG_INFO,
3185 "pid %d (%s), jid %d, uid %d: exited on "
3186 "signal %d%s\n", p->p_pid, p->p_comm,
3187 p->p_ucred->cr_prison->pr_id,
3188 td->td_ucred ? td->td_ucred->cr_uid : -1,
3189 sig &~ WCOREFLAG,
3190 sig & WCOREFLAG ? " (core dumped)" : "");
3191 } else
3192 PROC_UNLOCK(p);
3193 exit1(td, 0, sig);
3194 /* NOTREACHED */
3195 }
3196
3197 /*
3198 * Send queued SIGCHLD to parent when child process's state
3199 * is changed.
3200 */
3201 static void
sigparent(struct proc * p,int reason,int status)3202 sigparent(struct proc *p, int reason, int status)
3203 {
3204 PROC_LOCK_ASSERT(p, MA_OWNED);
3205 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3206
3207 if (p->p_ksi != NULL) {
3208 p->p_ksi->ksi_signo = SIGCHLD;
3209 p->p_ksi->ksi_code = reason;
3210 p->p_ksi->ksi_status = status;
3211 p->p_ksi->ksi_pid = p->p_pid;
3212 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3213 if (KSI_ONQ(p->p_ksi))
3214 return;
3215 }
3216 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3217 }
3218
3219 static void
childproc_jobstate(struct proc * p,int reason,int sig)3220 childproc_jobstate(struct proc *p, int reason, int sig)
3221 {
3222 struct sigacts *ps;
3223
3224 PROC_LOCK_ASSERT(p, MA_OWNED);
3225 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3226
3227 /*
3228 * Wake up parent sleeping in kern_wait(), also send
3229 * SIGCHLD to parent, but SIGCHLD does not guarantee
3230 * that parent will awake, because parent may masked
3231 * the signal.
3232 */
3233 p->p_pptr->p_flag |= P_STATCHILD;
3234 wakeup(p->p_pptr);
3235
3236 ps = p->p_pptr->p_sigacts;
3237 mtx_lock(&ps->ps_mtx);
3238 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3239 mtx_unlock(&ps->ps_mtx);
3240 sigparent(p, reason, sig);
3241 } else
3242 mtx_unlock(&ps->ps_mtx);
3243 }
3244
3245 void
childproc_stopped(struct proc * p,int reason)3246 childproc_stopped(struct proc *p, int reason)
3247 {
3248
3249 childproc_jobstate(p, reason, p->p_xsig);
3250 }
3251
3252 void
childproc_continued(struct proc * p)3253 childproc_continued(struct proc *p)
3254 {
3255 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3256 }
3257
3258 void
childproc_exited(struct proc * p)3259 childproc_exited(struct proc *p)
3260 {
3261 int reason, status;
3262
3263 if (WCOREDUMP(p->p_xsig)) {
3264 reason = CLD_DUMPED;
3265 status = WTERMSIG(p->p_xsig);
3266 } else if (WIFSIGNALED(p->p_xsig)) {
3267 reason = CLD_KILLED;
3268 status = WTERMSIG(p->p_xsig);
3269 } else {
3270 reason = CLD_EXITED;
3271 status = p->p_xexit;
3272 }
3273 /*
3274 * XXX avoid calling wakeup(p->p_pptr), the work is
3275 * done in exit1().
3276 */
3277 sigparent(p, reason, status);
3278 }
3279
3280 /*
3281 * We only have 1 character for the core count in the format
3282 * string, so the range will be 0-9
3283 */
3284 #define MAX_NUM_CORES 10
3285 static int num_cores = 5;
3286
3287 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3288 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3289 {
3290 int error;
3291 int new_val;
3292
3293 new_val = num_cores;
3294 error = sysctl_handle_int(oidp, &new_val, 0, req);
3295 if (error != 0 || req->newptr == NULL)
3296 return (error);
3297 if (new_val > MAX_NUM_CORES)
3298 new_val = MAX_NUM_CORES;
3299 if (new_val < 0)
3300 new_val = 0;
3301 num_cores = new_val;
3302 return (0);
3303 }
3304 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
3305 0, sizeof(int), sysctl_debug_num_cores_check, "I", "");
3306
3307 #define GZ_SUFFIX ".gz"
3308
3309 #ifdef GZIO
3310 static int compress_user_cores = 1;
3311 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RWTUN,
3312 &compress_user_cores, 0, "Compression of user corefiles");
3313
3314 int compress_user_cores_gzlevel = 6;
3315 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RWTUN,
3316 &compress_user_cores_gzlevel, 0, "Corefile gzip compression level");
3317 #else
3318 static int compress_user_cores = 0;
3319 #endif
3320
3321 /*
3322 * Protect the access to corefilename[] by allproc_lock.
3323 */
3324 #define corefilename_lock allproc_lock
3325
3326 static char corefilename[MAXPATHLEN] = {"%N.core"};
3327 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3328
3329 static int
sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)3330 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
3331 {
3332 int error;
3333
3334 sx_xlock(&corefilename_lock);
3335 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
3336 req);
3337 sx_xunlock(&corefilename_lock);
3338
3339 return (error);
3340 }
3341 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
3342 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
3343 "Process corefile name format string");
3344
3345 static void
vnode_close_locked(struct thread * td,struct vnode * vp)3346 vnode_close_locked(struct thread *td, struct vnode *vp)
3347 {
3348
3349 VOP_UNLOCK(vp, 0);
3350 vn_close(vp, FWRITE, td->td_ucred, td);
3351 }
3352
3353 /*
3354 * If the core format has a %I in it, then we need to check
3355 * for existing corefiles before defining a name.
3356 * To do this we iterate over 0..num_cores to find a
3357 * non-existing core file name to use. If all core files are
3358 * already used we choose the oldest one.
3359 */
3360 static int
corefile_open_last(struct thread * td,char * name,int indexpos,struct vnode ** vpp)3361 corefile_open_last(struct thread *td, char *name, int indexpos,
3362 struct vnode **vpp)
3363 {
3364 struct vnode *oldvp, *nextvp, *vp;
3365 struct vattr vattr;
3366 struct nameidata nd;
3367 int error, i, flags, oflags, cmode;
3368 struct timespec lasttime;
3369
3370 nextvp = oldvp = NULL;
3371 cmode = S_IRUSR | S_IWUSR;
3372 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3373 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3374
3375 for (i = 0; i < num_cores; i++) {
3376 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3377 name[indexpos] = '0' + i;
3378
3379 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3380 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3381 NULL);
3382 if (error != 0)
3383 break;
3384
3385 vp = nd.ni_vp;
3386 NDFREE(&nd, NDF_ONLY_PNBUF);
3387 if ((flags & O_CREAT) == O_CREAT) {
3388 nextvp = vp;
3389 break;
3390 }
3391
3392 error = VOP_GETATTR(vp, &vattr, td->td_ucred);
3393 if (error != 0) {
3394 vnode_close_locked(td, vp);
3395 break;
3396 }
3397
3398 if (oldvp == NULL ||
3399 lasttime.tv_sec > vattr.va_mtime.tv_sec ||
3400 (lasttime.tv_sec == vattr.va_mtime.tv_sec &&
3401 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) {
3402 if (oldvp != NULL)
3403 vnode_close_locked(td, oldvp);
3404 oldvp = vp;
3405 lasttime = vattr.va_mtime;
3406 } else {
3407 vnode_close_locked(td, vp);
3408 }
3409 }
3410
3411 if (oldvp != NULL) {
3412 if (nextvp == NULL) {
3413 if ((td->td_proc->p_flag & P_SUGID) != 0) {
3414 error = EFAULT;
3415 vnode_close_locked(td, oldvp);
3416 } else {
3417 nextvp = oldvp;
3418 }
3419 } else {
3420 vnode_close_locked(td, oldvp);
3421 }
3422 }
3423 if (error != 0) {
3424 if (nextvp != NULL)
3425 vnode_close_locked(td, oldvp);
3426 } else {
3427 *vpp = nextvp;
3428 }
3429
3430 return (error);
3431 }
3432
3433 /*
3434 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3435 * Expand the name described in corefilename, using name, uid, and pid
3436 * and open/create core file.
3437 * corefilename is a printf-like string, with three format specifiers:
3438 * %N name of process ("name")
3439 * %P process id (pid)
3440 * %U user id (uid)
3441 * For example, "%N.core" is the default; they can be disabled completely
3442 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3443 * This is controlled by the sysctl variable kern.corefile (see above).
3444 */
3445 static int
corefile_open(const char * comm,uid_t uid,pid_t pid,struct thread * td,int compress,struct vnode ** vpp,char ** namep)3446 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
3447 int compress, struct vnode **vpp, char **namep)
3448 {
3449 struct sbuf sb;
3450 struct nameidata nd;
3451 const char *format;
3452 char *hostname, *name;
3453 int cmode, error, flags, i, indexpos, oflags;
3454
3455 hostname = NULL;
3456 format = corefilename;
3457 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
3458 indexpos = -1;
3459 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
3460 sx_slock(&corefilename_lock);
3461 for (i = 0; format[i] != '\0'; i++) {
3462 switch (format[i]) {
3463 case '%': /* Format character */
3464 i++;
3465 switch (format[i]) {
3466 case '%':
3467 sbuf_putc(&sb, '%');
3468 break;
3469 case 'H': /* hostname */
3470 if (hostname == NULL) {
3471 hostname = malloc(MAXHOSTNAMELEN,
3472 M_TEMP, M_WAITOK);
3473 }
3474 getcredhostname(td->td_ucred, hostname,
3475 MAXHOSTNAMELEN);
3476 sbuf_printf(&sb, "%s", hostname);
3477 break;
3478 case 'I': /* autoincrementing index */
3479 sbuf_printf(&sb, "0");
3480 indexpos = sbuf_len(&sb) - 1;
3481 break;
3482 case 'N': /* process name */
3483 sbuf_printf(&sb, "%s", comm);
3484 break;
3485 case 'P': /* process id */
3486 sbuf_printf(&sb, "%u", pid);
3487 break;
3488 case 'U': /* user id */
3489 sbuf_printf(&sb, "%u", uid);
3490 break;
3491 default:
3492 log(LOG_ERR,
3493 "Unknown format character %c in "
3494 "corename `%s'\n", format[i], format);
3495 break;
3496 }
3497 break;
3498 default:
3499 sbuf_putc(&sb, format[i]);
3500 break;
3501 }
3502 }
3503 sx_sunlock(&corefilename_lock);
3504 free(hostname, M_TEMP);
3505 if (compress)
3506 sbuf_printf(&sb, GZ_SUFFIX);
3507 if (sbuf_error(&sb) != 0) {
3508 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
3509 "long\n", (long)pid, comm, (u_long)uid);
3510 sbuf_delete(&sb);
3511 free(name, M_TEMP);
3512 return (ENOMEM);
3513 }
3514 sbuf_finish(&sb);
3515 sbuf_delete(&sb);
3516
3517 if (indexpos != -1) {
3518 error = corefile_open_last(td, name, indexpos, vpp);
3519 if (error != 0) {
3520 log(LOG_ERR,
3521 "pid %d (%s), uid (%u): Path `%s' failed "
3522 "on initial open test, error = %d\n",
3523 pid, comm, uid, name, error);
3524 }
3525 } else {
3526 cmode = S_IRUSR | S_IWUSR;
3527 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3528 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3529 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3530 if ((td->td_proc->p_flag & P_SUGID) != 0)
3531 flags |= O_EXCL;
3532
3533 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3534 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3535 NULL);
3536 if (error == 0) {
3537 *vpp = nd.ni_vp;
3538 NDFREE(&nd, NDF_ONLY_PNBUF);
3539 }
3540 }
3541
3542 if (error != 0) {
3543 #ifdef AUDIT
3544 audit_proc_coredump(td, name, error);
3545 #endif
3546 free(name, M_TEMP);
3547 return (error);
3548 }
3549 *namep = name;
3550 return (0);
3551 }
3552
3553 static int
coredump_sanitise_path(const char * path)3554 coredump_sanitise_path(const char *path)
3555 {
3556 size_t i;
3557
3558 /*
3559 * Only send a subset of ASCII to devd(8) because it
3560 * might pass these strings to sh -c.
3561 */
3562 for (i = 0; path[i]; i++)
3563 if (!(isalpha(path[i]) || isdigit(path[i])) &&
3564 path[i] != '/' && path[i] != '.' &&
3565 path[i] != '-')
3566 return (0);
3567
3568 return (1);
3569 }
3570
3571 /*
3572 * Dump a process' core. The main routine does some
3573 * policy checking, and creates the name of the coredump;
3574 * then it passes on a vnode and a size limit to the process-specific
3575 * coredump routine if there is one; if there _is not_ one, it returns
3576 * ENOSYS; otherwise it returns the error from the process-specific routine.
3577 */
3578
3579 static int
coredump(struct thread * td)3580 coredump(struct thread *td)
3581 {
3582 struct proc *p = td->td_proc;
3583 struct ucred *cred = td->td_ucred;
3584 struct vnode *vp;
3585 struct flock lf;
3586 struct vattr vattr;
3587 int error, error1, locked;
3588 char *name; /* name of corefile */
3589 void *rl_cookie;
3590 off_t limit;
3591 char *data = NULL;
3592 char *fullpath, *freepath = NULL;
3593 size_t len;
3594 static const char comm_name[] = "comm=";
3595 static const char core_name[] = "core=";
3596
3597 PROC_LOCK_ASSERT(p, MA_OWNED);
3598 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
3599 _STOPEVENT(p, S_CORE, 0);
3600
3601 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
3602 (p->p_flag2 & P2_NOTRACE) != 0) {
3603 PROC_UNLOCK(p);
3604 return (EFAULT);
3605 }
3606
3607 /*
3608 * Note that the bulk of limit checking is done after
3609 * the corefile is created. The exception is if the limit
3610 * for corefiles is 0, in which case we don't bother
3611 * creating the corefile at all. This layout means that
3612 * a corefile is truncated instead of not being created,
3613 * if it is larger than the limit.
3614 */
3615 limit = (off_t)lim_cur(td, RLIMIT_CORE);
3616 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
3617 PROC_UNLOCK(p);
3618 return (EFBIG);
3619 }
3620 PROC_UNLOCK(p);
3621
3622 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
3623 compress_user_cores, &vp, &name);
3624 if (error != 0)
3625 return (error);
3626
3627 /*
3628 * Don't dump to non-regular files or files with links.
3629 * Do not dump into system files. Effective user must own the corefile.
3630 */
3631 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
3632 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 ||
3633 vattr.va_uid != cred->cr_uid) {
3634 VOP_UNLOCK(vp, 0);
3635 error = EFAULT;
3636 goto out;
3637 }
3638
3639 VOP_UNLOCK(vp, 0);
3640
3641 /* Postpone other writers, including core dumps of other processes. */
3642 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
3643
3644 lf.l_whence = SEEK_SET;
3645 lf.l_start = 0;
3646 lf.l_len = 0;
3647 lf.l_type = F_WRLCK;
3648 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
3649
3650 VATTR_NULL(&vattr);
3651 vattr.va_size = 0;
3652 if (set_core_nodump_flag)
3653 vattr.va_flags = UF_NODUMP;
3654 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3655 VOP_SETATTR(vp, &vattr, cred);
3656 VOP_UNLOCK(vp, 0);
3657 PROC_LOCK(p);
3658 p->p_acflag |= ACORE;
3659 PROC_UNLOCK(p);
3660
3661 if (p->p_sysent->sv_coredump != NULL) {
3662 error = p->p_sysent->sv_coredump(td, vp, limit,
3663 compress_user_cores ? IMGACT_CORE_COMPRESS : 0);
3664 } else {
3665 error = ENOSYS;
3666 }
3667
3668 if (locked) {
3669 lf.l_type = F_UNLCK;
3670 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3671 }
3672 vn_rangelock_unlock(vp, rl_cookie);
3673
3674 /*
3675 * Notify the userland helper that a process triggered a core dump.
3676 * This allows the helper to run an automated debugging session.
3677 */
3678 if (error != 0 || coredump_devctl == 0)
3679 goto out;
3680 len = MAXPATHLEN * 2 + sizeof(comm_name) - 1 +
3681 sizeof(' ') + sizeof(core_name) - 1;
3682 data = malloc(len, M_TEMP, M_WAITOK);
3683 if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
3684 goto out;
3685 if (!coredump_sanitise_path(fullpath))
3686 goto out;
3687 snprintf(data, len, "%s%s ", comm_name, fullpath);
3688 free(freepath, M_TEMP);
3689 freepath = NULL;
3690 if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
3691 goto out;
3692 if (!coredump_sanitise_path(fullpath))
3693 goto out;
3694 strlcat(data, core_name, len);
3695 strlcat(data, fullpath, len);
3696 devctl_notify("kernel", "signal", "coredump", data);
3697 out:
3698 error1 = vn_close(vp, FWRITE, cred, td);
3699 if (error == 0)
3700 error = error1;
3701 #ifdef AUDIT
3702 audit_proc_coredump(td, name, error);
3703 #endif
3704 free(freepath, M_TEMP);
3705 free(data, M_TEMP);
3706 free(name, M_TEMP);
3707 return (error);
3708 }
3709
3710 /*
3711 * Nonexistent system call-- signal process (may want to handle it). Flag
3712 * error in case process won't see signal immediately (blocked or ignored).
3713 */
3714 #ifndef _SYS_SYSPROTO_H_
3715 struct nosys_args {
3716 int dummy;
3717 };
3718 #endif
3719 /* ARGSUSED */
3720 int
nosys(struct thread * td,struct nosys_args * args)3721 nosys(struct thread *td, struct nosys_args *args)
3722 {
3723 struct proc *p;
3724
3725 p = td->td_proc;
3726
3727 PROC_LOCK(p);
3728 tdsignal(td, SIGSYS);
3729 PROC_UNLOCK(p);
3730 if (kern_lognosys == 1 || kern_lognosys == 3) {
3731 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3732 td->td_sa.code);
3733 }
3734 if (kern_lognosys == 2 || kern_lognosys == 3 ||
3735 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
3736 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3737 td->td_sa.code);
3738 }
3739 return (ENOSYS);
3740 }
3741
3742 /*
3743 * Send a SIGIO or SIGURG signal to a process or process group using stored
3744 * credentials rather than those of the current process.
3745 */
3746 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)3747 pgsigio(struct sigio **sigiop, int sig, int checkctty)
3748 {
3749 ksiginfo_t ksi;
3750 struct sigio *sigio;
3751
3752 ksiginfo_init(&ksi);
3753 ksi.ksi_signo = sig;
3754 ksi.ksi_code = SI_KERNEL;
3755
3756 SIGIO_LOCK();
3757 sigio = *sigiop;
3758 if (sigio == NULL) {
3759 SIGIO_UNLOCK();
3760 return;
3761 }
3762 if (sigio->sio_pgid > 0) {
3763 PROC_LOCK(sigio->sio_proc);
3764 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3765 kern_psignal(sigio->sio_proc, sig);
3766 PROC_UNLOCK(sigio->sio_proc);
3767 } else if (sigio->sio_pgid < 0) {
3768 struct proc *p;
3769
3770 PGRP_LOCK(sigio->sio_pgrp);
3771 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3772 PROC_LOCK(p);
3773 if (p->p_state == PRS_NORMAL &&
3774 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3775 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3776 kern_psignal(p, sig);
3777 PROC_UNLOCK(p);
3778 }
3779 PGRP_UNLOCK(sigio->sio_pgrp);
3780 }
3781 SIGIO_UNLOCK();
3782 }
3783
3784 static int
filt_sigattach(struct knote * kn)3785 filt_sigattach(struct knote *kn)
3786 {
3787 struct proc *p = curproc;
3788
3789 kn->kn_ptr.p_proc = p;
3790 kn->kn_flags |= EV_CLEAR; /* automatically set */
3791
3792 knlist_add(p->p_klist, kn, 0);
3793
3794 return (0);
3795 }
3796
3797 static void
filt_sigdetach(struct knote * kn)3798 filt_sigdetach(struct knote *kn)
3799 {
3800 struct proc *p = kn->kn_ptr.p_proc;
3801
3802 knlist_remove(p->p_klist, kn, 0);
3803 }
3804
3805 /*
3806 * signal knotes are shared with proc knotes, so we apply a mask to
3807 * the hint in order to differentiate them from process hints. This
3808 * could be avoided by using a signal-specific knote list, but probably
3809 * isn't worth the trouble.
3810 */
3811 static int
filt_signal(struct knote * kn,long hint)3812 filt_signal(struct knote *kn, long hint)
3813 {
3814
3815 if (hint & NOTE_SIGNAL) {
3816 hint &= ~NOTE_SIGNAL;
3817
3818 if (kn->kn_id == hint)
3819 kn->kn_data++;
3820 }
3821 return (kn->kn_data != 0);
3822 }
3823
3824 struct sigacts *
sigacts_alloc(void)3825 sigacts_alloc(void)
3826 {
3827 struct sigacts *ps;
3828
3829 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3830 refcount_init(&ps->ps_refcnt, 1);
3831 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3832 return (ps);
3833 }
3834
3835 void
sigacts_free(struct sigacts * ps)3836 sigacts_free(struct sigacts *ps)
3837 {
3838
3839 if (refcount_release(&ps->ps_refcnt) == 0)
3840 return;
3841 mtx_destroy(&ps->ps_mtx);
3842 free(ps, M_SUBPROC);
3843 }
3844
3845 struct sigacts *
sigacts_hold(struct sigacts * ps)3846 sigacts_hold(struct sigacts *ps)
3847 {
3848
3849 refcount_acquire(&ps->ps_refcnt);
3850 return (ps);
3851 }
3852
3853 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3854 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3855 {
3856
3857 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3858 mtx_lock(&src->ps_mtx);
3859 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3860 mtx_unlock(&src->ps_mtx);
3861 }
3862
3863 int
sigacts_shared(struct sigacts * ps)3864 sigacts_shared(struct sigacts *ps)
3865 {
3866
3867 return (ps->ps_refcnt > 1);
3868 }
3869
3870 void
sig_drop_caught(struct proc * p)3871 sig_drop_caught(struct proc *p)
3872 {
3873 int sig;
3874 struct sigacts *ps;
3875
3876 ps = p->p_sigacts;
3877 PROC_LOCK_ASSERT(p, MA_OWNED);
3878 mtx_assert(&ps->ps_mtx, MA_OWNED);
3879 while (SIGNOTEMPTY(ps->ps_sigcatch)) {
3880 sig = sig_ffs(&ps->ps_sigcatch);
3881 sigdflt(ps, sig);
3882 if ((sigprop(sig) & SA_IGNORE) != 0)
3883 sigqueue_delete_proc(p, sig);
3884 }
3885 }
3886