1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
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/compressor.h>
53 #include <sys/condvar.h>
54 #include <sys/event.h>
55 #include <sys/fcntl.h>
56 #include <sys/imgact.h>
57 #include <sys/kernel.h>
58 #include <sys/ktr.h>
59 #include <sys/ktrace.h>
60 #include <sys/limits.h>
61 #include <sys/lock.h>
62 #include <sys/malloc.h>
63 #include <sys/mutex.h>
64 #include <sys/refcount.h>
65 #include <sys/namei.h>
66 #include <sys/proc.h>
67 #include <sys/procdesc.h>
68 #include <sys/posix4.h>
69 #include <sys/pioctl.h>
70 #include <sys/racct.h>
71 #include <sys/resourcevar.h>
72 #include <sys/sdt.h>
73 #include <sys/sbuf.h>
74 #include <sys/sleepqueue.h>
75 #include <sys/smp.h>
76 #include <sys/stat.h>
77 #include <sys/sx.h>
78 #include <sys/syscallsubr.h>
79 #include <sys/sysctl.h>
80 #include <sys/sysent.h>
81 #include <sys/syslog.h>
82 #include <sys/sysproto.h>
83 #include <sys/timers.h>
84 #include <sys/unistd.h>
85 #include <sys/wait.h>
86 #include <vm/vm.h>
87 #include <vm/vm_extern.h>
88 #include <vm/uma.h>
89
90 #include <sys/jail.h>
91
92 #include <machine/cpu.h>
93
94 #include <security/audit/audit.h>
95
96 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
97
98 SDT_PROVIDER_DECLARE(proc);
99 SDT_PROBE_DEFINE3(proc, , , signal__send,
100 "struct thread *", "struct proc *", "int");
101 SDT_PROBE_DEFINE2(proc, , , signal__clear,
102 "int", "ksiginfo_t *");
103 SDT_PROBE_DEFINE3(proc, , , signal__discard,
104 "struct thread *", "struct proc *", "int");
105
106 static int coredump(struct thread *);
107 static int killpg1(struct thread *td, int sig, int pgid, int all,
108 ksiginfo_t *ksi);
109 static int issignal(struct thread *td);
110 static int sigprop(int sig);
111 static void tdsigwakeup(struct thread *, int, sig_t, int);
112 static int sig_suspend_threads(struct thread *, struct proc *, int);
113 static int filt_sigattach(struct knote *kn);
114 static void filt_sigdetach(struct knote *kn);
115 static int filt_signal(struct knote *kn, long hint);
116 static struct thread *sigtd(struct proc *p, int sig, int prop);
117 static void sigqueue_start(void);
118
119 static uma_zone_t ksiginfo_zone = NULL;
120 struct filterops sig_filtops = {
121 .f_isfd = 0,
122 .f_attach = filt_sigattach,
123 .f_detach = filt_sigdetach,
124 .f_event = filt_signal,
125 };
126
127 static int kern_logsigexit = 1;
128 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
129 &kern_logsigexit, 0,
130 "Log processes quitting on abnormal signals to syslog(3)");
131
132 static int kern_forcesigexit = 1;
133 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
134 &kern_forcesigexit, 0, "Force trap signal to be handled");
135
136 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0,
137 "POSIX real time signal");
138
139 static int max_pending_per_proc = 128;
140 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
141 &max_pending_per_proc, 0, "Max pending signals per proc");
142
143 static int preallocate_siginfo = 1024;
144 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
145 &preallocate_siginfo, 0, "Preallocated signal memory size");
146
147 static int signal_overflow = 0;
148 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
149 &signal_overflow, 0, "Number of signals overflew");
150
151 static int signal_alloc_fail = 0;
152 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
153 &signal_alloc_fail, 0, "signals failed to be allocated");
154
155 static int kern_lognosys = 0;
156 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
157 "Log invalid syscalls");
158
159 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
160
161 /*
162 * Policy -- Can ucred cr1 send SIGIO to process cr2?
163 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
164 * in the right situations.
165 */
166 #define CANSIGIO(cr1, cr2) \
167 ((cr1)->cr_uid == 0 || \
168 (cr1)->cr_ruid == (cr2)->cr_ruid || \
169 (cr1)->cr_uid == (cr2)->cr_ruid || \
170 (cr1)->cr_ruid == (cr2)->cr_uid || \
171 (cr1)->cr_uid == (cr2)->cr_uid)
172
173 static int sugid_coredump;
174 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN,
175 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
176
177 static int capmode_coredump;
178 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN,
179 &capmode_coredump, 0, "Allow processes in capability mode to dump core");
180
181 static int do_coredump = 1;
182 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
183 &do_coredump, 0, "Enable/Disable coredumps");
184
185 static int set_core_nodump_flag = 0;
186 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
187 0, "Enable setting the NODUMP flag on coredump files");
188
189 static int coredump_devctl = 0;
190 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
191 0, "Generate a devctl notification when processes coredump");
192
193 /*
194 * Signal properties and actions.
195 * The array below categorizes the signals and their default actions
196 * according to the following properties:
197 */
198 #define SIGPROP_KILL 0x01 /* terminates process by default */
199 #define SIGPROP_CORE 0x02 /* ditto and coredumps */
200 #define SIGPROP_STOP 0x04 /* suspend process */
201 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */
202 #define SIGPROP_IGNORE 0x10 /* ignore by default */
203 #define SIGPROP_CONT 0x20 /* continue if suspended */
204 #define SIGPROP_CANTMASK 0x40 /* non-maskable, catchable */
205
206 static int sigproptbl[NSIG] = {
207 [SIGHUP] = SIGPROP_KILL,
208 [SIGINT] = SIGPROP_KILL,
209 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE,
210 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE,
211 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE,
212 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE,
213 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE,
214 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE,
215 [SIGKILL] = SIGPROP_KILL,
216 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE,
217 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE,
218 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE,
219 [SIGPIPE] = SIGPROP_KILL,
220 [SIGALRM] = SIGPROP_KILL,
221 [SIGTERM] = SIGPROP_KILL,
222 [SIGURG] = SIGPROP_IGNORE,
223 [SIGSTOP] = SIGPROP_STOP,
224 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP,
225 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT,
226 [SIGCHLD] = SIGPROP_IGNORE,
227 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP,
228 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP,
229 [SIGIO] = SIGPROP_IGNORE,
230 [SIGXCPU] = SIGPROP_KILL,
231 [SIGXFSZ] = SIGPROP_KILL,
232 [SIGVTALRM] = SIGPROP_KILL,
233 [SIGPROF] = SIGPROP_KILL,
234 [SIGWINCH] = SIGPROP_IGNORE,
235 [SIGINFO] = SIGPROP_IGNORE,
236 [SIGUSR1] = SIGPROP_KILL,
237 [SIGUSR2] = SIGPROP_KILL,
238 };
239
240 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
241
242 static void
sigqueue_start(void)243 sigqueue_start(void)
244 {
245 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
246 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
247 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
248 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
249 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
250 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
251 }
252
253 ksiginfo_t *
ksiginfo_alloc(int wait)254 ksiginfo_alloc(int wait)
255 {
256 int flags;
257
258 flags = M_ZERO;
259 if (! wait)
260 flags |= M_NOWAIT;
261 if (ksiginfo_zone != NULL)
262 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
263 return (NULL);
264 }
265
266 void
ksiginfo_free(ksiginfo_t * ksi)267 ksiginfo_free(ksiginfo_t *ksi)
268 {
269 uma_zfree(ksiginfo_zone, ksi);
270 }
271
272 static __inline int
ksiginfo_tryfree(ksiginfo_t * ksi)273 ksiginfo_tryfree(ksiginfo_t *ksi)
274 {
275 if (!(ksi->ksi_flags & KSI_EXT)) {
276 uma_zfree(ksiginfo_zone, ksi);
277 return (1);
278 }
279 return (0);
280 }
281
282 void
sigqueue_init(sigqueue_t * list,struct proc * p)283 sigqueue_init(sigqueue_t *list, struct proc *p)
284 {
285 SIGEMPTYSET(list->sq_signals);
286 SIGEMPTYSET(list->sq_kill);
287 SIGEMPTYSET(list->sq_ptrace);
288 TAILQ_INIT(&list->sq_list);
289 list->sq_proc = p;
290 list->sq_flags = SQ_INIT;
291 }
292
293 /*
294 * Get a signal's ksiginfo.
295 * Return:
296 * 0 - signal not found
297 * others - signal number
298 */
299 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)300 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
301 {
302 struct proc *p = sq->sq_proc;
303 struct ksiginfo *ksi, *next;
304 int count = 0;
305
306 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
307
308 if (!SIGISMEMBER(sq->sq_signals, signo))
309 return (0);
310
311 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
312 count++;
313 SIGDELSET(sq->sq_ptrace, signo);
314 si->ksi_flags |= KSI_PTRACE;
315 }
316 if (SIGISMEMBER(sq->sq_kill, signo)) {
317 count++;
318 if (count == 1)
319 SIGDELSET(sq->sq_kill, signo);
320 }
321
322 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
323 if (ksi->ksi_signo == signo) {
324 if (count == 0) {
325 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
326 ksi->ksi_sigq = NULL;
327 ksiginfo_copy(ksi, si);
328 if (ksiginfo_tryfree(ksi) && p != NULL)
329 p->p_pendingcnt--;
330 }
331 if (++count > 1)
332 break;
333 }
334 }
335
336 if (count <= 1)
337 SIGDELSET(sq->sq_signals, signo);
338 si->ksi_signo = signo;
339 return (signo);
340 }
341
342 void
sigqueue_take(ksiginfo_t * ksi)343 sigqueue_take(ksiginfo_t *ksi)
344 {
345 struct ksiginfo *kp;
346 struct proc *p;
347 sigqueue_t *sq;
348
349 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
350 return;
351
352 p = sq->sq_proc;
353 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
354 ksi->ksi_sigq = NULL;
355 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
356 p->p_pendingcnt--;
357
358 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
359 kp = TAILQ_NEXT(kp, ksi_link)) {
360 if (kp->ksi_signo == ksi->ksi_signo)
361 break;
362 }
363 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
364 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
365 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
366 }
367
368 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)369 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
370 {
371 struct proc *p = sq->sq_proc;
372 struct ksiginfo *ksi;
373 int ret = 0;
374
375 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
376
377 /*
378 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
379 * for these signals.
380 */
381 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
382 SIGADDSET(sq->sq_kill, signo);
383 goto out_set_bit;
384 }
385
386 /* directly insert the ksi, don't copy it */
387 if (si->ksi_flags & KSI_INS) {
388 if (si->ksi_flags & KSI_HEAD)
389 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
390 else
391 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
392 si->ksi_sigq = sq;
393 goto out_set_bit;
394 }
395
396 if (__predict_false(ksiginfo_zone == NULL)) {
397 SIGADDSET(sq->sq_kill, signo);
398 goto out_set_bit;
399 }
400
401 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
402 signal_overflow++;
403 ret = EAGAIN;
404 } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
405 signal_alloc_fail++;
406 ret = EAGAIN;
407 } else {
408 if (p != NULL)
409 p->p_pendingcnt++;
410 ksiginfo_copy(si, ksi);
411 ksi->ksi_signo = signo;
412 if (si->ksi_flags & KSI_HEAD)
413 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
414 else
415 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
416 ksi->ksi_sigq = sq;
417 }
418
419 if (ret != 0) {
420 if ((si->ksi_flags & KSI_PTRACE) != 0) {
421 SIGADDSET(sq->sq_ptrace, signo);
422 ret = 0;
423 goto out_set_bit;
424 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
425 (si->ksi_flags & KSI_SIGQ) == 0) {
426 SIGADDSET(sq->sq_kill, signo);
427 ret = 0;
428 goto out_set_bit;
429 }
430 return (ret);
431 }
432
433 out_set_bit:
434 SIGADDSET(sq->sq_signals, signo);
435 return (ret);
436 }
437
438 void
sigqueue_flush(sigqueue_t * sq)439 sigqueue_flush(sigqueue_t *sq)
440 {
441 struct proc *p = sq->sq_proc;
442 ksiginfo_t *ksi;
443
444 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
445
446 if (p != NULL)
447 PROC_LOCK_ASSERT(p, MA_OWNED);
448
449 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
450 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
451 ksi->ksi_sigq = NULL;
452 if (ksiginfo_tryfree(ksi) && p != NULL)
453 p->p_pendingcnt--;
454 }
455
456 SIGEMPTYSET(sq->sq_signals);
457 SIGEMPTYSET(sq->sq_kill);
458 SIGEMPTYSET(sq->sq_ptrace);
459 }
460
461 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)462 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
463 {
464 sigset_t tmp;
465 struct proc *p1, *p2;
466 ksiginfo_t *ksi, *next;
467
468 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
469 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
470 p1 = src->sq_proc;
471 p2 = dst->sq_proc;
472 /* Move siginfo to target list */
473 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
474 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
475 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
476 if (p1 != NULL)
477 p1->p_pendingcnt--;
478 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
479 ksi->ksi_sigq = dst;
480 if (p2 != NULL)
481 p2->p_pendingcnt++;
482 }
483 }
484
485 /* Move pending bits to target list */
486 tmp = src->sq_kill;
487 SIGSETAND(tmp, *set);
488 SIGSETOR(dst->sq_kill, tmp);
489 SIGSETNAND(src->sq_kill, tmp);
490
491 tmp = src->sq_ptrace;
492 SIGSETAND(tmp, *set);
493 SIGSETOR(dst->sq_ptrace, tmp);
494 SIGSETNAND(src->sq_ptrace, tmp);
495
496 tmp = src->sq_signals;
497 SIGSETAND(tmp, *set);
498 SIGSETOR(dst->sq_signals, tmp);
499 SIGSETNAND(src->sq_signals, tmp);
500 }
501
502 #if 0
503 static void
504 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
505 {
506 sigset_t set;
507
508 SIGEMPTYSET(set);
509 SIGADDSET(set, signo);
510 sigqueue_move_set(src, dst, &set);
511 }
512 #endif
513
514 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)515 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
516 {
517 struct proc *p = sq->sq_proc;
518 ksiginfo_t *ksi, *next;
519
520 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
521
522 /* Remove siginfo queue */
523 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
524 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
525 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
526 ksi->ksi_sigq = NULL;
527 if (ksiginfo_tryfree(ksi) && p != NULL)
528 p->p_pendingcnt--;
529 }
530 }
531 SIGSETNAND(sq->sq_kill, *set);
532 SIGSETNAND(sq->sq_ptrace, *set);
533 SIGSETNAND(sq->sq_signals, *set);
534 }
535
536 void
sigqueue_delete(sigqueue_t * sq,int signo)537 sigqueue_delete(sigqueue_t *sq, int signo)
538 {
539 sigset_t set;
540
541 SIGEMPTYSET(set);
542 SIGADDSET(set, signo);
543 sigqueue_delete_set(sq, &set);
544 }
545
546 /* Remove a set of signals for a process */
547 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)548 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
549 {
550 sigqueue_t worklist;
551 struct thread *td0;
552
553 PROC_LOCK_ASSERT(p, MA_OWNED);
554
555 sigqueue_init(&worklist, NULL);
556 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
557
558 FOREACH_THREAD_IN_PROC(p, td0)
559 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
560
561 sigqueue_flush(&worklist);
562 }
563
564 void
sigqueue_delete_proc(struct proc * p,int signo)565 sigqueue_delete_proc(struct proc *p, int signo)
566 {
567 sigset_t set;
568
569 SIGEMPTYSET(set);
570 SIGADDSET(set, signo);
571 sigqueue_delete_set_proc(p, &set);
572 }
573
574 static void
sigqueue_delete_stopmask_proc(struct proc * p)575 sigqueue_delete_stopmask_proc(struct proc *p)
576 {
577 sigset_t set;
578
579 SIGEMPTYSET(set);
580 SIGADDSET(set, SIGSTOP);
581 SIGADDSET(set, SIGTSTP);
582 SIGADDSET(set, SIGTTIN);
583 SIGADDSET(set, SIGTTOU);
584 sigqueue_delete_set_proc(p, &set);
585 }
586
587 /*
588 * Determine signal that should be delivered to thread td, the current
589 * thread, 0 if none. If there is a pending stop signal with default
590 * action, the process stops in issignal().
591 */
592 int
cursig(struct thread * td)593 cursig(struct thread *td)
594 {
595 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
596 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
597 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
598 return (SIGPENDING(td) ? issignal(td) : 0);
599 }
600
601 /*
602 * Arrange for ast() to handle unmasked pending signals on return to user
603 * mode. This must be called whenever a signal is added to td_sigqueue or
604 * unmasked in td_sigmask.
605 */
606 void
signotify(struct thread * td)607 signotify(struct thread *td)
608 {
609
610 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
611
612 if (SIGPENDING(td)) {
613 thread_lock(td);
614 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
615 thread_unlock(td);
616 }
617 }
618
619 /*
620 * Returns 1 (true) if altstack is configured for the thread, and the
621 * passed stack bottom address falls into the altstack range. Handles
622 * the 43 compat special case where the alt stack size is zero.
623 */
624 int
sigonstack(size_t sp)625 sigonstack(size_t sp)
626 {
627 struct thread *td;
628
629 td = curthread;
630 if ((td->td_pflags & TDP_ALTSTACK) == 0)
631 return (0);
632 #if defined(COMPAT_43)
633 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0)
634 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0);
635 #endif
636 return (sp >= (size_t)td->td_sigstk.ss_sp &&
637 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp);
638 }
639
640 static __inline int
sigprop(int sig)641 sigprop(int sig)
642 {
643
644 if (sig > 0 && sig < nitems(sigproptbl))
645 return (sigproptbl[sig]);
646 return (0);
647 }
648
649 int
sig_ffs(sigset_t * set)650 sig_ffs(sigset_t *set)
651 {
652 int i;
653
654 for (i = 0; i < _SIG_WORDS; i++)
655 if (set->__bits[i])
656 return (ffs(set->__bits[i]) + (i * 32));
657 return (0);
658 }
659
660 static bool
sigact_flag_test(const struct sigaction * act,int flag)661 sigact_flag_test(const struct sigaction *act, int flag)
662 {
663
664 /*
665 * SA_SIGINFO is reset when signal disposition is set to
666 * ignore or default. Other flags are kept according to user
667 * settings.
668 */
669 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
670 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
671 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
672 }
673
674 /*
675 * kern_sigaction
676 * sigaction
677 * freebsd4_sigaction
678 * osigaction
679 */
680 int
kern_sigaction(struct thread * td,int sig,const struct sigaction * act,struct sigaction * oact,int flags)681 kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
682 struct sigaction *oact, int flags)
683 {
684 struct sigacts *ps;
685 struct proc *p = td->td_proc;
686
687 if (!_SIG_VALID(sig))
688 return (EINVAL);
689 if (act != NULL && act->sa_handler != SIG_DFL &&
690 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
691 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
692 SA_NOCLDWAIT | SA_SIGINFO)) != 0)
693 return (EINVAL);
694
695 PROC_LOCK(p);
696 ps = p->p_sigacts;
697 mtx_lock(&ps->ps_mtx);
698 if (oact) {
699 memset(oact, 0, sizeof(*oact));
700 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
701 if (SIGISMEMBER(ps->ps_sigonstack, sig))
702 oact->sa_flags |= SA_ONSTACK;
703 if (!SIGISMEMBER(ps->ps_sigintr, sig))
704 oact->sa_flags |= SA_RESTART;
705 if (SIGISMEMBER(ps->ps_sigreset, sig))
706 oact->sa_flags |= SA_RESETHAND;
707 if (SIGISMEMBER(ps->ps_signodefer, sig))
708 oact->sa_flags |= SA_NODEFER;
709 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
710 oact->sa_flags |= SA_SIGINFO;
711 oact->sa_sigaction =
712 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
713 } else
714 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
715 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
716 oact->sa_flags |= SA_NOCLDSTOP;
717 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
718 oact->sa_flags |= SA_NOCLDWAIT;
719 }
720 if (act) {
721 if ((sig == SIGKILL || sig == SIGSTOP) &&
722 act->sa_handler != SIG_DFL) {
723 mtx_unlock(&ps->ps_mtx);
724 PROC_UNLOCK(p);
725 return (EINVAL);
726 }
727
728 /*
729 * Change setting atomically.
730 */
731
732 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
733 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
734 if (sigact_flag_test(act, SA_SIGINFO)) {
735 ps->ps_sigact[_SIG_IDX(sig)] =
736 (__sighandler_t *)act->sa_sigaction;
737 SIGADDSET(ps->ps_siginfo, sig);
738 } else {
739 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
740 SIGDELSET(ps->ps_siginfo, sig);
741 }
742 if (!sigact_flag_test(act, SA_RESTART))
743 SIGADDSET(ps->ps_sigintr, sig);
744 else
745 SIGDELSET(ps->ps_sigintr, sig);
746 if (sigact_flag_test(act, SA_ONSTACK))
747 SIGADDSET(ps->ps_sigonstack, sig);
748 else
749 SIGDELSET(ps->ps_sigonstack, sig);
750 if (sigact_flag_test(act, SA_RESETHAND))
751 SIGADDSET(ps->ps_sigreset, sig);
752 else
753 SIGDELSET(ps->ps_sigreset, sig);
754 if (sigact_flag_test(act, SA_NODEFER))
755 SIGADDSET(ps->ps_signodefer, sig);
756 else
757 SIGDELSET(ps->ps_signodefer, sig);
758 if (sig == SIGCHLD) {
759 if (act->sa_flags & SA_NOCLDSTOP)
760 ps->ps_flag |= PS_NOCLDSTOP;
761 else
762 ps->ps_flag &= ~PS_NOCLDSTOP;
763 if (act->sa_flags & SA_NOCLDWAIT) {
764 /*
765 * Paranoia: since SA_NOCLDWAIT is implemented
766 * by reparenting the dying child to PID 1 (and
767 * trust it to reap the zombie), PID 1 itself
768 * is forbidden to set SA_NOCLDWAIT.
769 */
770 if (p->p_pid == 1)
771 ps->ps_flag &= ~PS_NOCLDWAIT;
772 else
773 ps->ps_flag |= PS_NOCLDWAIT;
774 } else
775 ps->ps_flag &= ~PS_NOCLDWAIT;
776 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
777 ps->ps_flag |= PS_CLDSIGIGN;
778 else
779 ps->ps_flag &= ~PS_CLDSIGIGN;
780 }
781 /*
782 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
783 * and for signals set to SIG_DFL where the default is to
784 * ignore. However, don't put SIGCONT in ps_sigignore, as we
785 * have to restart the process.
786 */
787 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
788 (sigprop(sig) & SIGPROP_IGNORE &&
789 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
790 /* never to be seen again */
791 sigqueue_delete_proc(p, sig);
792 if (sig != SIGCONT)
793 /* easier in psignal */
794 SIGADDSET(ps->ps_sigignore, sig);
795 SIGDELSET(ps->ps_sigcatch, sig);
796 } else {
797 SIGDELSET(ps->ps_sigignore, sig);
798 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
799 SIGDELSET(ps->ps_sigcatch, sig);
800 else
801 SIGADDSET(ps->ps_sigcatch, sig);
802 }
803 #ifdef COMPAT_FREEBSD4
804 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
805 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
806 (flags & KSA_FREEBSD4) == 0)
807 SIGDELSET(ps->ps_freebsd4, sig);
808 else
809 SIGADDSET(ps->ps_freebsd4, sig);
810 #endif
811 #ifdef COMPAT_43
812 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
813 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
814 (flags & KSA_OSIGSET) == 0)
815 SIGDELSET(ps->ps_osigset, sig);
816 else
817 SIGADDSET(ps->ps_osigset, sig);
818 #endif
819 }
820 mtx_unlock(&ps->ps_mtx);
821 PROC_UNLOCK(p);
822 return (0);
823 }
824
825 #ifndef _SYS_SYSPROTO_H_
826 struct sigaction_args {
827 int sig;
828 struct sigaction *act;
829 struct sigaction *oact;
830 };
831 #endif
832 int
sys_sigaction(struct thread * td,struct sigaction_args * uap)833 sys_sigaction(struct thread *td, struct sigaction_args *uap)
834 {
835 struct sigaction act, oact;
836 struct sigaction *actp, *oactp;
837 int error;
838
839 actp = (uap->act != NULL) ? &act : NULL;
840 oactp = (uap->oact != NULL) ? &oact : NULL;
841 if (actp) {
842 error = copyin(uap->act, actp, sizeof(act));
843 if (error)
844 return (error);
845 }
846 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
847 if (oactp && !error)
848 error = copyout(oactp, uap->oact, sizeof(oact));
849 return (error);
850 }
851
852 #ifdef COMPAT_FREEBSD4
853 #ifndef _SYS_SYSPROTO_H_
854 struct freebsd4_sigaction_args {
855 int sig;
856 struct sigaction *act;
857 struct sigaction *oact;
858 };
859 #endif
860 int
freebsd4_sigaction(struct thread * td,struct freebsd4_sigaction_args * uap)861 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
862 {
863 struct sigaction act, oact;
864 struct sigaction *actp, *oactp;
865 int error;
866
867
868 actp = (uap->act != NULL) ? &act : NULL;
869 oactp = (uap->oact != NULL) ? &oact : NULL;
870 if (actp) {
871 error = copyin(uap->act, actp, sizeof(act));
872 if (error)
873 return (error);
874 }
875 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
876 if (oactp && !error)
877 error = copyout(oactp, uap->oact, sizeof(oact));
878 return (error);
879 }
880 #endif /* COMAPT_FREEBSD4 */
881
882 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
883 #ifndef _SYS_SYSPROTO_H_
884 struct osigaction_args {
885 int signum;
886 struct osigaction *nsa;
887 struct osigaction *osa;
888 };
889 #endif
890 int
osigaction(struct thread * td,struct osigaction_args * uap)891 osigaction(struct thread *td, struct osigaction_args *uap)
892 {
893 struct osigaction sa;
894 struct sigaction nsa, osa;
895 struct sigaction *nsap, *osap;
896 int error;
897
898 if (uap->signum <= 0 || uap->signum >= ONSIG)
899 return (EINVAL);
900
901 nsap = (uap->nsa != NULL) ? &nsa : NULL;
902 osap = (uap->osa != NULL) ? &osa : NULL;
903
904 if (nsap) {
905 error = copyin(uap->nsa, &sa, sizeof(sa));
906 if (error)
907 return (error);
908 nsap->sa_handler = sa.sa_handler;
909 nsap->sa_flags = sa.sa_flags;
910 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
911 }
912 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
913 if (osap && !error) {
914 sa.sa_handler = osap->sa_handler;
915 sa.sa_flags = osap->sa_flags;
916 SIG2OSIG(osap->sa_mask, sa.sa_mask);
917 error = copyout(&sa, uap->osa, sizeof(sa));
918 }
919 return (error);
920 }
921
922 #if !defined(__i386__)
923 /* Avoid replicating the same stub everywhere */
924 int
osigreturn(struct thread * td,struct osigreturn_args * uap)925 osigreturn(struct thread *td, struct osigreturn_args *uap)
926 {
927
928 return (nosys(td, (struct nosys_args *)uap));
929 }
930 #endif
931 #endif /* COMPAT_43 */
932
933 /*
934 * Initialize signal state for process 0;
935 * set to ignore signals that are ignored by default.
936 */
937 void
siginit(struct proc * p)938 siginit(struct proc *p)
939 {
940 int i;
941 struct sigacts *ps;
942
943 PROC_LOCK(p);
944 ps = p->p_sigacts;
945 mtx_lock(&ps->ps_mtx);
946 for (i = 1; i <= NSIG; i++) {
947 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) {
948 SIGADDSET(ps->ps_sigignore, i);
949 }
950 }
951 mtx_unlock(&ps->ps_mtx);
952 PROC_UNLOCK(p);
953 }
954
955 /*
956 * Reset specified signal to the default disposition.
957 */
958 static void
sigdflt(struct sigacts * ps,int sig)959 sigdflt(struct sigacts *ps, int sig)
960 {
961
962 mtx_assert(&ps->ps_mtx, MA_OWNED);
963 SIGDELSET(ps->ps_sigcatch, sig);
964 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT)
965 SIGADDSET(ps->ps_sigignore, sig);
966 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
967 SIGDELSET(ps->ps_siginfo, sig);
968 }
969
970 /*
971 * Reset signals for an exec of the specified process.
972 */
973 void
execsigs(struct proc * p)974 execsigs(struct proc *p)
975 {
976 sigset_t osigignore;
977 struct sigacts *ps;
978 int sig;
979 struct thread *td;
980
981 /*
982 * Reset caught signals. Held signals remain held
983 * through td_sigmask (unless they were caught,
984 * and are now ignored by default).
985 */
986 PROC_LOCK_ASSERT(p, MA_OWNED);
987 ps = p->p_sigacts;
988 mtx_lock(&ps->ps_mtx);
989 while (SIGNOTEMPTY(ps->ps_sigcatch)) {
990 sig = sig_ffs(&ps->ps_sigcatch);
991 sigdflt(ps, sig);
992 if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
993 sigqueue_delete_proc(p, sig);
994 }
995
996 /*
997 * As CloudABI processes cannot modify signal handlers, fully
998 * reset all signals to their default behavior. Do ignore
999 * SIGPIPE, as it would otherwise be impossible to recover from
1000 * writes to broken pipes and sockets.
1001 */
1002 if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) {
1003 osigignore = ps->ps_sigignore;
1004 while (SIGNOTEMPTY(osigignore)) {
1005 sig = sig_ffs(&osigignore);
1006 SIGDELSET(osigignore, sig);
1007 if (sig != SIGPIPE)
1008 sigdflt(ps, sig);
1009 }
1010 SIGADDSET(ps->ps_sigignore, SIGPIPE);
1011 }
1012
1013 /*
1014 * Reset stack state to the user stack.
1015 * Clear set of signals caught on the signal stack.
1016 */
1017 td = curthread;
1018 MPASS(td->td_proc == p);
1019 td->td_sigstk.ss_flags = SS_DISABLE;
1020 td->td_sigstk.ss_size = 0;
1021 td->td_sigstk.ss_sp = 0;
1022 td->td_pflags &= ~TDP_ALTSTACK;
1023 /*
1024 * Reset no zombies if child dies flag as Solaris does.
1025 */
1026 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1027 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1028 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1029 mtx_unlock(&ps->ps_mtx);
1030 }
1031
1032 /*
1033 * kern_sigprocmask()
1034 *
1035 * Manipulate signal mask.
1036 */
1037 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)1038 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1039 int flags)
1040 {
1041 sigset_t new_block, oset1;
1042 struct proc *p;
1043 int error;
1044
1045 p = td->td_proc;
1046 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1047 PROC_LOCK_ASSERT(p, MA_OWNED);
1048 else
1049 PROC_LOCK(p);
1050 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1051 ? MA_OWNED : MA_NOTOWNED);
1052 if (oset != NULL)
1053 *oset = td->td_sigmask;
1054
1055 error = 0;
1056 if (set != NULL) {
1057 switch (how) {
1058 case SIG_BLOCK:
1059 SIG_CANTMASK(*set);
1060 oset1 = td->td_sigmask;
1061 SIGSETOR(td->td_sigmask, *set);
1062 new_block = td->td_sigmask;
1063 SIGSETNAND(new_block, oset1);
1064 break;
1065 case SIG_UNBLOCK:
1066 SIGSETNAND(td->td_sigmask, *set);
1067 signotify(td);
1068 goto out;
1069 case SIG_SETMASK:
1070 SIG_CANTMASK(*set);
1071 oset1 = td->td_sigmask;
1072 if (flags & SIGPROCMASK_OLD)
1073 SIGSETLO(td->td_sigmask, *set);
1074 else
1075 td->td_sigmask = *set;
1076 new_block = td->td_sigmask;
1077 SIGSETNAND(new_block, oset1);
1078 signotify(td);
1079 break;
1080 default:
1081 error = EINVAL;
1082 goto out;
1083 }
1084
1085 /*
1086 * The new_block set contains signals that were not previously
1087 * blocked, but are blocked now.
1088 *
1089 * In case we block any signal that was not previously blocked
1090 * for td, and process has the signal pending, try to schedule
1091 * signal delivery to some thread that does not block the
1092 * signal, possibly waking it up.
1093 */
1094 if (p->p_numthreads != 1)
1095 reschedule_signals(p, new_block, flags);
1096 }
1097
1098 out:
1099 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1100 PROC_UNLOCK(p);
1101 return (error);
1102 }
1103
1104 #ifndef _SYS_SYSPROTO_H_
1105 struct sigprocmask_args {
1106 int how;
1107 const sigset_t *set;
1108 sigset_t *oset;
1109 };
1110 #endif
1111 int
sys_sigprocmask(struct thread * td,struct sigprocmask_args * uap)1112 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
1113 {
1114 sigset_t set, oset;
1115 sigset_t *setp, *osetp;
1116 int error;
1117
1118 setp = (uap->set != NULL) ? &set : NULL;
1119 osetp = (uap->oset != NULL) ? &oset : NULL;
1120 if (setp) {
1121 error = copyin(uap->set, setp, sizeof(set));
1122 if (error)
1123 return (error);
1124 }
1125 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1126 if (osetp && !error) {
1127 error = copyout(osetp, uap->oset, sizeof(oset));
1128 }
1129 return (error);
1130 }
1131
1132 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1133 #ifndef _SYS_SYSPROTO_H_
1134 struct osigprocmask_args {
1135 int how;
1136 osigset_t mask;
1137 };
1138 #endif
1139 int
osigprocmask(struct thread * td,struct osigprocmask_args * uap)1140 osigprocmask(struct thread *td, struct osigprocmask_args *uap)
1141 {
1142 sigset_t set, oset;
1143 int error;
1144
1145 OSIG2SIG(uap->mask, set);
1146 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1147 SIG2OSIG(oset, td->td_retval[0]);
1148 return (error);
1149 }
1150 #endif /* COMPAT_43 */
1151
1152 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1153 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1154 {
1155 ksiginfo_t ksi;
1156 sigset_t set;
1157 int error;
1158
1159 error = copyin(uap->set, &set, sizeof(set));
1160 if (error) {
1161 td->td_retval[0] = error;
1162 return (0);
1163 }
1164
1165 error = kern_sigtimedwait(td, set, &ksi, NULL);
1166 if (error) {
1167 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1168 error = ERESTART;
1169 if (error == ERESTART)
1170 return (error);
1171 td->td_retval[0] = error;
1172 return (0);
1173 }
1174
1175 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1176 td->td_retval[0] = error;
1177 return (0);
1178 }
1179
1180 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1181 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1182 {
1183 struct timespec ts;
1184 struct timespec *timeout;
1185 sigset_t set;
1186 ksiginfo_t ksi;
1187 int error;
1188
1189 if (uap->timeout) {
1190 error = copyin(uap->timeout, &ts, sizeof(ts));
1191 if (error)
1192 return (error);
1193
1194 timeout = &ts;
1195 } else
1196 timeout = NULL;
1197
1198 error = copyin(uap->set, &set, sizeof(set));
1199 if (error)
1200 return (error);
1201
1202 error = kern_sigtimedwait(td, set, &ksi, timeout);
1203 if (error)
1204 return (error);
1205
1206 if (uap->info)
1207 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1208
1209 if (error == 0)
1210 td->td_retval[0] = ksi.ksi_signo;
1211 return (error);
1212 }
1213
1214 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1215 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1216 {
1217 ksiginfo_t ksi;
1218 sigset_t set;
1219 int error;
1220
1221 error = copyin(uap->set, &set, sizeof(set));
1222 if (error)
1223 return (error);
1224
1225 error = kern_sigtimedwait(td, set, &ksi, NULL);
1226 if (error)
1227 return (error);
1228
1229 if (uap->info)
1230 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1231
1232 if (error == 0)
1233 td->td_retval[0] = ksi.ksi_signo;
1234 return (error);
1235 }
1236
1237 static void
proc_td_siginfo_capture(struct thread * td,siginfo_t * si)1238 proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
1239 {
1240 struct thread *thr;
1241
1242 FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
1243 if (thr == td)
1244 thr->td_si = *si;
1245 else
1246 thr->td_si.si_signo = 0;
1247 }
1248 }
1249
1250 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1251 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1252 struct timespec *timeout)
1253 {
1254 struct sigacts *ps;
1255 sigset_t saved_mask, new_block;
1256 struct proc *p;
1257 int error, sig, timo, timevalid = 0;
1258 struct timespec rts, ets, ts;
1259 struct timeval tv;
1260
1261 p = td->td_proc;
1262 error = 0;
1263 ets.tv_sec = 0;
1264 ets.tv_nsec = 0;
1265
1266 if (timeout != NULL) {
1267 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1268 timevalid = 1;
1269 getnanouptime(&rts);
1270 timespecadd(&rts, timeout, &ets);
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 timespecsub(&ets, &rts, &ts);
1311 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1312 timo = tvtohz(&tv);
1313 } else {
1314 timo = 0;
1315 }
1316
1317 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
1318
1319 if (timeout != NULL) {
1320 if (error == ERESTART) {
1321 /* Timeout can not be restarted. */
1322 error = EINTR;
1323 } else if (error == EAGAIN) {
1324 /* We will calculate timeout by ourself. */
1325 error = 0;
1326 }
1327 }
1328 }
1329
1330 new_block = saved_mask;
1331 SIGSETNAND(new_block, td->td_sigmask);
1332 td->td_sigmask = saved_mask;
1333 /*
1334 * Fewer signals can be delivered to us, reschedule signal
1335 * notification.
1336 */
1337 if (p->p_numthreads != 1)
1338 reschedule_signals(p, new_block, 0);
1339
1340 if (error == 0) {
1341 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1342
1343 if (ksi->ksi_code == SI_TIMER)
1344 itimer_accept(p, ksi->ksi_timerid, ksi);
1345
1346 #ifdef KTRACE
1347 if (KTRPOINT(td, KTR_PSIG)) {
1348 sig_t action;
1349
1350 mtx_lock(&ps->ps_mtx);
1351 action = ps->ps_sigact[_SIG_IDX(sig)];
1352 mtx_unlock(&ps->ps_mtx);
1353 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1354 }
1355 #endif
1356 if (sig == SIGKILL) {
1357 proc_td_siginfo_capture(td, &ksi->ksi_info);
1358 sigexit(td, sig);
1359 }
1360 }
1361 PROC_UNLOCK(p);
1362 return (error);
1363 }
1364
1365 #ifndef _SYS_SYSPROTO_H_
1366 struct sigpending_args {
1367 sigset_t *set;
1368 };
1369 #endif
1370 int
sys_sigpending(struct thread * td,struct sigpending_args * uap)1371 sys_sigpending(struct thread *td, struct sigpending_args *uap)
1372 {
1373 struct proc *p = td->td_proc;
1374 sigset_t pending;
1375
1376 PROC_LOCK(p);
1377 pending = p->p_sigqueue.sq_signals;
1378 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1379 PROC_UNLOCK(p);
1380 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1381 }
1382
1383 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1384 #ifndef _SYS_SYSPROTO_H_
1385 struct osigpending_args {
1386 int dummy;
1387 };
1388 #endif
1389 int
osigpending(struct thread * td,struct osigpending_args * uap)1390 osigpending(struct thread *td, struct osigpending_args *uap)
1391 {
1392 struct proc *p = td->td_proc;
1393 sigset_t pending;
1394
1395 PROC_LOCK(p);
1396 pending = p->p_sigqueue.sq_signals;
1397 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1398 PROC_UNLOCK(p);
1399 SIG2OSIG(pending, td->td_retval[0]);
1400 return (0);
1401 }
1402 #endif /* COMPAT_43 */
1403
1404 #if defined(COMPAT_43)
1405 /*
1406 * Generalized interface signal handler, 4.3-compatible.
1407 */
1408 #ifndef _SYS_SYSPROTO_H_
1409 struct osigvec_args {
1410 int signum;
1411 struct sigvec *nsv;
1412 struct sigvec *osv;
1413 };
1414 #endif
1415 /* ARGSUSED */
1416 int
osigvec(struct thread * td,struct osigvec_args * uap)1417 osigvec(struct thread *td, struct osigvec_args *uap)
1418 {
1419 struct sigvec vec;
1420 struct sigaction nsa, osa;
1421 struct sigaction *nsap, *osap;
1422 int error;
1423
1424 if (uap->signum <= 0 || uap->signum >= ONSIG)
1425 return (EINVAL);
1426 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1427 osap = (uap->osv != NULL) ? &osa : NULL;
1428 if (nsap) {
1429 error = copyin(uap->nsv, &vec, sizeof(vec));
1430 if (error)
1431 return (error);
1432 nsap->sa_handler = vec.sv_handler;
1433 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1434 nsap->sa_flags = vec.sv_flags;
1435 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1436 }
1437 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1438 if (osap && !error) {
1439 vec.sv_handler = osap->sa_handler;
1440 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1441 vec.sv_flags = osap->sa_flags;
1442 vec.sv_flags &= ~SA_NOCLDWAIT;
1443 vec.sv_flags ^= SA_RESTART;
1444 error = copyout(&vec, uap->osv, sizeof(vec));
1445 }
1446 return (error);
1447 }
1448
1449 #ifndef _SYS_SYSPROTO_H_
1450 struct osigblock_args {
1451 int mask;
1452 };
1453 #endif
1454 int
osigblock(struct thread * td,struct osigblock_args * uap)1455 osigblock(struct thread *td, struct osigblock_args *uap)
1456 {
1457 sigset_t set, oset;
1458
1459 OSIG2SIG(uap->mask, set);
1460 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1461 SIG2OSIG(oset, td->td_retval[0]);
1462 return (0);
1463 }
1464
1465 #ifndef _SYS_SYSPROTO_H_
1466 struct osigsetmask_args {
1467 int mask;
1468 };
1469 #endif
1470 int
osigsetmask(struct thread * td,struct osigsetmask_args * uap)1471 osigsetmask(struct thread *td, struct osigsetmask_args *uap)
1472 {
1473 sigset_t set, oset;
1474
1475 OSIG2SIG(uap->mask, set);
1476 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1477 SIG2OSIG(oset, td->td_retval[0]);
1478 return (0);
1479 }
1480 #endif /* COMPAT_43 */
1481
1482 /*
1483 * Suspend calling thread until signal, providing mask to be set in the
1484 * meantime.
1485 */
1486 #ifndef _SYS_SYSPROTO_H_
1487 struct sigsuspend_args {
1488 const sigset_t *sigmask;
1489 };
1490 #endif
1491 /* ARGSUSED */
1492 int
sys_sigsuspend(struct thread * td,struct sigsuspend_args * uap)1493 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
1494 {
1495 sigset_t mask;
1496 int error;
1497
1498 error = copyin(uap->sigmask, &mask, sizeof(mask));
1499 if (error)
1500 return (error);
1501 return (kern_sigsuspend(td, mask));
1502 }
1503
1504 int
kern_sigsuspend(struct thread * td,sigset_t mask)1505 kern_sigsuspend(struct thread *td, sigset_t mask)
1506 {
1507 struct proc *p = td->td_proc;
1508 int has_sig, sig;
1509
1510 /*
1511 * When returning from sigsuspend, we want
1512 * the old mask to be restored after the
1513 * signal handler has finished. Thus, we
1514 * save it here and mark the sigacts structure
1515 * to indicate this.
1516 */
1517 PROC_LOCK(p);
1518 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1519 SIGPROCMASK_PROC_LOCKED);
1520 td->td_pflags |= TDP_OLDMASK;
1521
1522 /*
1523 * Process signals now. Otherwise, we can get spurious wakeup
1524 * due to signal entered process queue, but delivered to other
1525 * thread. But sigsuspend should return only on signal
1526 * delivery.
1527 */
1528 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1529 for (has_sig = 0; !has_sig;) {
1530 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1531 0) == 0)
1532 /* void */;
1533 thread_suspend_check(0);
1534 mtx_lock(&p->p_sigacts->ps_mtx);
1535 while ((sig = cursig(td)) != 0) {
1536 KASSERT(sig >= 0, ("sig %d", sig));
1537 has_sig += postsig(sig);
1538 }
1539 mtx_unlock(&p->p_sigacts->ps_mtx);
1540 }
1541 PROC_UNLOCK(p);
1542 td->td_errno = EINTR;
1543 td->td_pflags |= TDP_NERRNO;
1544 return (EJUSTRETURN);
1545 }
1546
1547 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1548 /*
1549 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1550 * convention: libc stub passes mask, not pointer, to save a copyin.
1551 */
1552 #ifndef _SYS_SYSPROTO_H_
1553 struct osigsuspend_args {
1554 osigset_t mask;
1555 };
1556 #endif
1557 /* ARGSUSED */
1558 int
osigsuspend(struct thread * td,struct osigsuspend_args * uap)1559 osigsuspend(struct thread *td, struct osigsuspend_args *uap)
1560 {
1561 sigset_t mask;
1562
1563 OSIG2SIG(uap->mask, mask);
1564 return (kern_sigsuspend(td, mask));
1565 }
1566 #endif /* COMPAT_43 */
1567
1568 #if defined(COMPAT_43)
1569 #ifndef _SYS_SYSPROTO_H_
1570 struct osigstack_args {
1571 struct sigstack *nss;
1572 struct sigstack *oss;
1573 };
1574 #endif
1575 /* ARGSUSED */
1576 int
osigstack(struct thread * td,struct osigstack_args * uap)1577 osigstack(struct thread *td, struct osigstack_args *uap)
1578 {
1579 struct sigstack nss, oss;
1580 int error = 0;
1581
1582 if (uap->nss != NULL) {
1583 error = copyin(uap->nss, &nss, sizeof(nss));
1584 if (error)
1585 return (error);
1586 }
1587 oss.ss_sp = td->td_sigstk.ss_sp;
1588 oss.ss_onstack = sigonstack(cpu_getstack(td));
1589 if (uap->nss != NULL) {
1590 td->td_sigstk.ss_sp = nss.ss_sp;
1591 td->td_sigstk.ss_size = 0;
1592 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1593 td->td_pflags |= TDP_ALTSTACK;
1594 }
1595 if (uap->oss != NULL)
1596 error = copyout(&oss, uap->oss, sizeof(oss));
1597
1598 return (error);
1599 }
1600 #endif /* COMPAT_43 */
1601
1602 #ifndef _SYS_SYSPROTO_H_
1603 struct sigaltstack_args {
1604 stack_t *ss;
1605 stack_t *oss;
1606 };
1607 #endif
1608 /* ARGSUSED */
1609 int
sys_sigaltstack(struct thread * td,struct sigaltstack_args * uap)1610 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
1611 {
1612 stack_t ss, oss;
1613 int error;
1614
1615 if (uap->ss != NULL) {
1616 error = copyin(uap->ss, &ss, sizeof(ss));
1617 if (error)
1618 return (error);
1619 }
1620 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1621 (uap->oss != NULL) ? &oss : NULL);
1622 if (error)
1623 return (error);
1624 if (uap->oss != NULL)
1625 error = copyout(&oss, uap->oss, sizeof(stack_t));
1626 return (error);
1627 }
1628
1629 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1630 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1631 {
1632 struct proc *p = td->td_proc;
1633 int oonstack;
1634
1635 oonstack = sigonstack(cpu_getstack(td));
1636
1637 if (oss != NULL) {
1638 *oss = td->td_sigstk;
1639 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1640 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1641 }
1642
1643 if (ss != NULL) {
1644 if (oonstack)
1645 return (EPERM);
1646 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1647 return (EINVAL);
1648 if (!(ss->ss_flags & SS_DISABLE)) {
1649 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1650 return (ENOMEM);
1651
1652 td->td_sigstk = *ss;
1653 td->td_pflags |= TDP_ALTSTACK;
1654 } else {
1655 td->td_pflags &= ~TDP_ALTSTACK;
1656 }
1657 }
1658 return (0);
1659 }
1660
1661 /*
1662 * Common code for kill process group/broadcast kill.
1663 * cp is calling process.
1664 */
1665 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1666 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1667 {
1668 struct proc *p;
1669 struct pgrp *pgrp;
1670 int err;
1671 int ret;
1672
1673 ret = ESRCH;
1674 if (all) {
1675 /*
1676 * broadcast
1677 */
1678 sx_slock(&allproc_lock);
1679 FOREACH_PROC_IN_SYSTEM(p) {
1680 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1681 p == td->td_proc || p->p_state == PRS_NEW) {
1682 continue;
1683 }
1684 PROC_LOCK(p);
1685 err = p_cansignal(td, p, sig);
1686 if (err == 0) {
1687 if (sig)
1688 pksignal(p, sig, ksi);
1689 ret = err;
1690 }
1691 else if (ret == ESRCH)
1692 ret = err;
1693 PROC_UNLOCK(p);
1694 }
1695 sx_sunlock(&allproc_lock);
1696 } else {
1697 sx_slock(&proctree_lock);
1698 if (pgid == 0) {
1699 /*
1700 * zero pgid means send to my process group.
1701 */
1702 pgrp = td->td_proc->p_pgrp;
1703 PGRP_LOCK(pgrp);
1704 } else {
1705 pgrp = pgfind(pgid);
1706 if (pgrp == NULL) {
1707 sx_sunlock(&proctree_lock);
1708 return (ESRCH);
1709 }
1710 }
1711 sx_sunlock(&proctree_lock);
1712 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1713 PROC_LOCK(p);
1714 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1715 p->p_state == PRS_NEW) {
1716 PROC_UNLOCK(p);
1717 continue;
1718 }
1719 err = p_cansignal(td, p, sig);
1720 if (err == 0) {
1721 if (sig)
1722 pksignal(p, sig, ksi);
1723 ret = err;
1724 }
1725 else if (ret == ESRCH)
1726 ret = err;
1727 PROC_UNLOCK(p);
1728 }
1729 PGRP_UNLOCK(pgrp);
1730 }
1731 return (ret);
1732 }
1733
1734 #ifndef _SYS_SYSPROTO_H_
1735 struct kill_args {
1736 int pid;
1737 int signum;
1738 };
1739 #endif
1740 /* ARGSUSED */
1741 int
sys_kill(struct thread * td,struct kill_args * uap)1742 sys_kill(struct thread *td, struct kill_args *uap)
1743 {
1744 ksiginfo_t ksi;
1745 struct proc *p;
1746 int error;
1747
1748 /*
1749 * A process in capability mode can send signals only to himself.
1750 * The main rationale behind this is that abort(3) is implemented as
1751 * kill(getpid(), SIGABRT).
1752 */
1753 if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid)
1754 return (ECAPMODE);
1755
1756 AUDIT_ARG_SIGNUM(uap->signum);
1757 AUDIT_ARG_PID(uap->pid);
1758 if ((u_int)uap->signum > _SIG_MAXSIG)
1759 return (EINVAL);
1760
1761 ksiginfo_init(&ksi);
1762 ksi.ksi_signo = uap->signum;
1763 ksi.ksi_code = SI_USER;
1764 ksi.ksi_pid = td->td_proc->p_pid;
1765 ksi.ksi_uid = td->td_ucred->cr_ruid;
1766
1767 if (uap->pid > 0) {
1768 /* kill single process */
1769 if ((p = pfind_any(uap->pid)) == NULL)
1770 return (ESRCH);
1771 AUDIT_ARG_PROCESS(p);
1772 error = p_cansignal(td, p, uap->signum);
1773 if (error == 0 && uap->signum)
1774 pksignal(p, uap->signum, &ksi);
1775 PROC_UNLOCK(p);
1776 return (error);
1777 }
1778 switch (uap->pid) {
1779 case -1: /* broadcast signal */
1780 return (killpg1(td, uap->signum, 0, 1, &ksi));
1781 case 0: /* signal own process group */
1782 return (killpg1(td, uap->signum, 0, 0, &ksi));
1783 default: /* negative explicit process group */
1784 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
1785 }
1786 /* NOTREACHED */
1787 }
1788
1789 int
sys_pdkill(struct thread * td,struct pdkill_args * uap)1790 sys_pdkill(struct thread *td, struct pdkill_args *uap)
1791 {
1792 struct proc *p;
1793 int error;
1794
1795 AUDIT_ARG_SIGNUM(uap->signum);
1796 AUDIT_ARG_FD(uap->fd);
1797 if ((u_int)uap->signum > _SIG_MAXSIG)
1798 return (EINVAL);
1799
1800 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p);
1801 if (error)
1802 return (error);
1803 AUDIT_ARG_PROCESS(p);
1804 error = p_cansignal(td, p, uap->signum);
1805 if (error == 0 && uap->signum)
1806 kern_psignal(p, uap->signum);
1807 PROC_UNLOCK(p);
1808 return (error);
1809 }
1810
1811 #if defined(COMPAT_43)
1812 #ifndef _SYS_SYSPROTO_H_
1813 struct okillpg_args {
1814 int pgid;
1815 int signum;
1816 };
1817 #endif
1818 /* ARGSUSED */
1819 int
okillpg(struct thread * td,struct okillpg_args * uap)1820 okillpg(struct thread *td, struct okillpg_args *uap)
1821 {
1822 ksiginfo_t ksi;
1823
1824 AUDIT_ARG_SIGNUM(uap->signum);
1825 AUDIT_ARG_PID(uap->pgid);
1826 if ((u_int)uap->signum > _SIG_MAXSIG)
1827 return (EINVAL);
1828
1829 ksiginfo_init(&ksi);
1830 ksi.ksi_signo = uap->signum;
1831 ksi.ksi_code = SI_USER;
1832 ksi.ksi_pid = td->td_proc->p_pid;
1833 ksi.ksi_uid = td->td_ucred->cr_ruid;
1834 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
1835 }
1836 #endif /* COMPAT_43 */
1837
1838 #ifndef _SYS_SYSPROTO_H_
1839 struct sigqueue_args {
1840 pid_t pid;
1841 int signum;
1842 /* union sigval */ void *value;
1843 };
1844 #endif
1845 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)1846 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
1847 {
1848 union sigval sv;
1849
1850 sv.sival_ptr = uap->value;
1851
1852 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
1853 }
1854
1855 int
kern_sigqueue(struct thread * td,pid_t pid,int signum,union sigval * value)1856 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
1857 {
1858 ksiginfo_t ksi;
1859 struct proc *p;
1860 int error;
1861
1862 if ((u_int)signum > _SIG_MAXSIG)
1863 return (EINVAL);
1864
1865 /*
1866 * Specification says sigqueue can only send signal to
1867 * single process.
1868 */
1869 if (pid <= 0)
1870 return (EINVAL);
1871
1872 if ((p = pfind_any(pid)) == NULL)
1873 return (ESRCH);
1874 error = p_cansignal(td, p, signum);
1875 if (error == 0 && signum != 0) {
1876 ksiginfo_init(&ksi);
1877 ksi.ksi_flags = KSI_SIGQ;
1878 ksi.ksi_signo = signum;
1879 ksi.ksi_code = SI_QUEUE;
1880 ksi.ksi_pid = td->td_proc->p_pid;
1881 ksi.ksi_uid = td->td_ucred->cr_ruid;
1882 ksi.ksi_value = *value;
1883 error = pksignal(p, ksi.ksi_signo, &ksi);
1884 }
1885 PROC_UNLOCK(p);
1886 return (error);
1887 }
1888
1889 /*
1890 * Send a signal to a process group.
1891 */
1892 void
gsignal(int pgid,int sig,ksiginfo_t * ksi)1893 gsignal(int pgid, int sig, ksiginfo_t *ksi)
1894 {
1895 struct pgrp *pgrp;
1896
1897 if (pgid != 0) {
1898 sx_slock(&proctree_lock);
1899 pgrp = pgfind(pgid);
1900 sx_sunlock(&proctree_lock);
1901 if (pgrp != NULL) {
1902 pgsignal(pgrp, sig, 0, ksi);
1903 PGRP_UNLOCK(pgrp);
1904 }
1905 }
1906 }
1907
1908 /*
1909 * Send a signal to a process group. If checktty is 1,
1910 * limit to members which have a controlling terminal.
1911 */
1912 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)1913 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
1914 {
1915 struct proc *p;
1916
1917 if (pgrp) {
1918 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
1919 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1920 PROC_LOCK(p);
1921 if (p->p_state == PRS_NORMAL &&
1922 (checkctty == 0 || p->p_flag & P_CONTROLT))
1923 pksignal(p, sig, ksi);
1924 PROC_UNLOCK(p);
1925 }
1926 }
1927 }
1928
1929
1930 /*
1931 * Recalculate the signal mask and reset the signal disposition after
1932 * usermode frame for delivery is formed. Should be called after
1933 * mach-specific routine, because sysent->sv_sendsig() needs correct
1934 * ps_siginfo and signal mask.
1935 */
1936 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)1937 postsig_done(int sig, struct thread *td, struct sigacts *ps)
1938 {
1939 sigset_t mask;
1940
1941 mtx_assert(&ps->ps_mtx, MA_OWNED);
1942 td->td_ru.ru_nsignals++;
1943 mask = ps->ps_catchmask[_SIG_IDX(sig)];
1944 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1945 SIGADDSET(mask, sig);
1946 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
1947 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
1948 if (SIGISMEMBER(ps->ps_sigreset, sig))
1949 sigdflt(ps, sig);
1950 }
1951
1952
1953 /*
1954 * Send a signal caused by a trap to the current thread. If it will be
1955 * caught immediately, deliver it with correct code. Otherwise, post it
1956 * normally.
1957 */
1958 void
trapsignal(struct thread * td,ksiginfo_t * ksi)1959 trapsignal(struct thread *td, ksiginfo_t *ksi)
1960 {
1961 struct sigacts *ps;
1962 struct proc *p;
1963 int sig;
1964 int code;
1965
1966 p = td->td_proc;
1967 sig = ksi->ksi_signo;
1968 code = ksi->ksi_code;
1969 KASSERT(_SIG_VALID(sig), ("invalid signal"));
1970
1971 PROC_LOCK(p);
1972 ps = p->p_sigacts;
1973 mtx_lock(&ps->ps_mtx);
1974 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
1975 !SIGISMEMBER(td->td_sigmask, sig)) {
1976 #ifdef KTRACE
1977 if (KTRPOINT(curthread, KTR_PSIG))
1978 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
1979 &td->td_sigmask, code);
1980 #endif
1981 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
1982 ksi, &td->td_sigmask);
1983 postsig_done(sig, td, ps);
1984 mtx_unlock(&ps->ps_mtx);
1985 } else {
1986 /*
1987 * Avoid a possible infinite loop if the thread
1988 * masking the signal or process is ignoring the
1989 * signal.
1990 */
1991 if (kern_forcesigexit &&
1992 (SIGISMEMBER(td->td_sigmask, sig) ||
1993 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
1994 SIGDELSET(td->td_sigmask, sig);
1995 SIGDELSET(ps->ps_sigcatch, sig);
1996 SIGDELSET(ps->ps_sigignore, sig);
1997 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1998 }
1999 mtx_unlock(&ps->ps_mtx);
2000 p->p_code = code; /* XXX for core dump/debugger */
2001 p->p_sig = sig; /* XXX to verify code */
2002 tdsendsignal(p, td, sig, ksi);
2003 }
2004 PROC_UNLOCK(p);
2005 }
2006
2007 static struct thread *
sigtd(struct proc * p,int sig,int prop)2008 sigtd(struct proc *p, int sig, int prop)
2009 {
2010 struct thread *td, *signal_td;
2011
2012 PROC_LOCK_ASSERT(p, MA_OWNED);
2013
2014 /*
2015 * Check if current thread can handle the signal without
2016 * switching context to another thread.
2017 */
2018 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
2019 return (curthread);
2020 signal_td = NULL;
2021 FOREACH_THREAD_IN_PROC(p, td) {
2022 if (!SIGISMEMBER(td->td_sigmask, sig)) {
2023 signal_td = td;
2024 break;
2025 }
2026 }
2027 if (signal_td == NULL)
2028 signal_td = FIRST_THREAD_IN_PROC(p);
2029 return (signal_td);
2030 }
2031
2032 /*
2033 * Send the signal to the process. If the signal has an action, the action
2034 * is usually performed by the target process rather than the caller; we add
2035 * the signal to the set of pending signals for the process.
2036 *
2037 * Exceptions:
2038 * o When a stop signal is sent to a sleeping process that takes the
2039 * default action, the process is stopped without awakening it.
2040 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2041 * regardless of the signal action (eg, blocked or ignored).
2042 *
2043 * Other ignored signals are discarded immediately.
2044 *
2045 * NB: This function may be entered from the debugger via the "kill" DDB
2046 * command. There is little that can be done to mitigate the possibly messy
2047 * side effects of this unwise possibility.
2048 */
2049 void
kern_psignal(struct proc * p,int sig)2050 kern_psignal(struct proc *p, int sig)
2051 {
2052 ksiginfo_t ksi;
2053
2054 ksiginfo_init(&ksi);
2055 ksi.ksi_signo = sig;
2056 ksi.ksi_code = SI_KERNEL;
2057 (void) tdsendsignal(p, NULL, sig, &ksi);
2058 }
2059
2060 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)2061 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2062 {
2063
2064 return (tdsendsignal(p, NULL, sig, ksi));
2065 }
2066
2067 /* Utility function for finding a thread to send signal event to. */
2068 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)2069 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
2070 {
2071 struct thread *td;
2072
2073 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2074 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2075 if (td == NULL)
2076 return (ESRCH);
2077 *ttd = td;
2078 } else {
2079 *ttd = NULL;
2080 PROC_LOCK(p);
2081 }
2082 return (0);
2083 }
2084
2085 void
tdsignal(struct thread * td,int sig)2086 tdsignal(struct thread *td, int sig)
2087 {
2088 ksiginfo_t ksi;
2089
2090 ksiginfo_init(&ksi);
2091 ksi.ksi_signo = sig;
2092 ksi.ksi_code = SI_KERNEL;
2093 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2094 }
2095
2096 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2097 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2098 {
2099
2100 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2101 }
2102
2103 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2104 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2105 {
2106 sig_t action;
2107 sigqueue_t *sigqueue;
2108 int prop;
2109 struct sigacts *ps;
2110 int intrval;
2111 int ret = 0;
2112 int wakeup_swapper;
2113
2114 MPASS(td == NULL || p == td->td_proc);
2115 PROC_LOCK_ASSERT(p, MA_OWNED);
2116
2117 if (!_SIG_VALID(sig))
2118 panic("%s(): invalid signal %d", __func__, sig);
2119
2120 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2121
2122 /*
2123 * IEEE Std 1003.1-2001: return success when killing a zombie.
2124 */
2125 if (p->p_state == PRS_ZOMBIE) {
2126 if (ksi && (ksi->ksi_flags & KSI_INS))
2127 ksiginfo_tryfree(ksi);
2128 return (ret);
2129 }
2130
2131 ps = p->p_sigacts;
2132 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
2133 prop = sigprop(sig);
2134
2135 if (td == NULL) {
2136 td = sigtd(p, sig, prop);
2137 sigqueue = &p->p_sigqueue;
2138 } else
2139 sigqueue = &td->td_sigqueue;
2140
2141 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2142
2143 /*
2144 * If the signal is being ignored,
2145 * then we forget about it immediately.
2146 * (Note: we don't set SIGCONT in ps_sigignore,
2147 * and if it is set to SIG_IGN,
2148 * action will be SIG_DFL here.)
2149 */
2150 mtx_lock(&ps->ps_mtx);
2151 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2152 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2153
2154 mtx_unlock(&ps->ps_mtx);
2155 if (ksi && (ksi->ksi_flags & KSI_INS))
2156 ksiginfo_tryfree(ksi);
2157 return (ret);
2158 }
2159 if (SIGISMEMBER(td->td_sigmask, sig))
2160 action = SIG_HOLD;
2161 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2162 action = SIG_CATCH;
2163 else
2164 action = SIG_DFL;
2165 if (SIGISMEMBER(ps->ps_sigintr, sig))
2166 intrval = EINTR;
2167 else
2168 intrval = ERESTART;
2169 mtx_unlock(&ps->ps_mtx);
2170
2171 if (prop & SIGPROP_CONT)
2172 sigqueue_delete_stopmask_proc(p);
2173 else if (prop & SIGPROP_STOP) {
2174 /*
2175 * If sending a tty stop signal to a member of an orphaned
2176 * process group, discard the signal here if the action
2177 * is default; don't stop the process below if sleeping,
2178 * and don't clear any pending SIGCONT.
2179 */
2180 if ((prop & SIGPROP_TTYSTOP) &&
2181 (p->p_pgrp->pg_jobc == 0) &&
2182 (action == SIG_DFL)) {
2183 if (ksi && (ksi->ksi_flags & KSI_INS))
2184 ksiginfo_tryfree(ksi);
2185 return (ret);
2186 }
2187 sigqueue_delete_proc(p, SIGCONT);
2188 if (p->p_flag & P_CONTINUED) {
2189 p->p_flag &= ~P_CONTINUED;
2190 PROC_LOCK(p->p_pptr);
2191 sigqueue_take(p->p_ksi);
2192 PROC_UNLOCK(p->p_pptr);
2193 }
2194 }
2195
2196 ret = sigqueue_add(sigqueue, sig, ksi);
2197 if (ret != 0)
2198 return (ret);
2199 signotify(td);
2200 /*
2201 * Defer further processing for signals which are held,
2202 * except that stopped processes must be continued by SIGCONT.
2203 */
2204 if (action == SIG_HOLD &&
2205 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG)))
2206 return (ret);
2207
2208 /* SIGKILL: Remove procfs STOPEVENTs. */
2209 if (sig == SIGKILL) {
2210 /* from procfs_ioctl.c: PIOCBIC */
2211 p->p_stops = 0;
2212 /* from procfs_ioctl.c: PIOCCONT */
2213 p->p_step = 0;
2214 wakeup(&p->p_step);
2215 }
2216 /*
2217 * Some signals have a process-wide effect and a per-thread
2218 * component. Most processing occurs when the process next
2219 * tries to cross the user boundary, however there are some
2220 * times when processing needs to be done immediately, such as
2221 * waking up threads so that they can cross the user boundary.
2222 * We try to do the per-process part here.
2223 */
2224 if (P_SHOULDSTOP(p)) {
2225 KASSERT(!(p->p_flag & P_WEXIT),
2226 ("signal to stopped but exiting process"));
2227 if (sig == SIGKILL) {
2228 /*
2229 * If traced process is already stopped,
2230 * then no further action is necessary.
2231 */
2232 if (p->p_flag & P_TRACED)
2233 goto out;
2234 /*
2235 * SIGKILL sets process running.
2236 * It will die elsewhere.
2237 * All threads must be restarted.
2238 */
2239 p->p_flag &= ~P_STOPPED_SIG;
2240 goto runfast;
2241 }
2242
2243 if (prop & SIGPROP_CONT) {
2244 /*
2245 * If traced process is already stopped,
2246 * then no further action is necessary.
2247 */
2248 if (p->p_flag & P_TRACED)
2249 goto out;
2250 /*
2251 * If SIGCONT is default (or ignored), we continue the
2252 * process but don't leave the signal in sigqueue as
2253 * it has no further action. If SIGCONT is held, we
2254 * continue the process and leave the signal in
2255 * sigqueue. If the process catches SIGCONT, let it
2256 * handle the signal itself. If it isn't waiting on
2257 * an event, it goes back to run state.
2258 * Otherwise, process goes back to sleep state.
2259 */
2260 p->p_flag &= ~P_STOPPED_SIG;
2261 PROC_SLOCK(p);
2262 if (p->p_numthreads == p->p_suspcount) {
2263 PROC_SUNLOCK(p);
2264 p->p_flag |= P_CONTINUED;
2265 p->p_xsig = SIGCONT;
2266 PROC_LOCK(p->p_pptr);
2267 childproc_continued(p);
2268 PROC_UNLOCK(p->p_pptr);
2269 PROC_SLOCK(p);
2270 }
2271 if (action == SIG_DFL) {
2272 thread_unsuspend(p);
2273 PROC_SUNLOCK(p);
2274 sigqueue_delete(sigqueue, sig);
2275 goto out;
2276 }
2277 if (action == SIG_CATCH) {
2278 /*
2279 * The process wants to catch it so it needs
2280 * to run at least one thread, but which one?
2281 */
2282 PROC_SUNLOCK(p);
2283 goto runfast;
2284 }
2285 /*
2286 * The signal is not ignored or caught.
2287 */
2288 thread_unsuspend(p);
2289 PROC_SUNLOCK(p);
2290 goto out;
2291 }
2292
2293 if (prop & SIGPROP_STOP) {
2294 /*
2295 * If traced process is already stopped,
2296 * then no further action is necessary.
2297 */
2298 if (p->p_flag & P_TRACED)
2299 goto out;
2300 /*
2301 * Already stopped, don't need to stop again
2302 * (If we did the shell could get confused).
2303 * Just make sure the signal STOP bit set.
2304 */
2305 p->p_flag |= P_STOPPED_SIG;
2306 sigqueue_delete(sigqueue, sig);
2307 goto out;
2308 }
2309
2310 /*
2311 * All other kinds of signals:
2312 * If a thread is sleeping interruptibly, simulate a
2313 * wakeup so that when it is continued it will be made
2314 * runnable and can look at the signal. However, don't make
2315 * the PROCESS runnable, leave it stopped.
2316 * It may run a bit until it hits a thread_suspend_check().
2317 */
2318 wakeup_swapper = 0;
2319 PROC_SLOCK(p);
2320 thread_lock(td);
2321 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
2322 wakeup_swapper = sleepq_abort(td, intrval);
2323 thread_unlock(td);
2324 PROC_SUNLOCK(p);
2325 if (wakeup_swapper)
2326 kick_proc0();
2327 goto out;
2328 /*
2329 * Mutexes are short lived. Threads waiting on them will
2330 * hit thread_suspend_check() soon.
2331 */
2332 } else if (p->p_state == PRS_NORMAL) {
2333 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2334 tdsigwakeup(td, sig, action, intrval);
2335 goto out;
2336 }
2337
2338 MPASS(action == SIG_DFL);
2339
2340 if (prop & SIGPROP_STOP) {
2341 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2342 goto out;
2343 p->p_flag |= P_STOPPED_SIG;
2344 p->p_xsig = sig;
2345 PROC_SLOCK(p);
2346 wakeup_swapper = sig_suspend_threads(td, p, 1);
2347 if (p->p_numthreads == p->p_suspcount) {
2348 /*
2349 * only thread sending signal to another
2350 * process can reach here, if thread is sending
2351 * signal to its process, because thread does
2352 * not suspend itself here, p_numthreads
2353 * should never be equal to p_suspcount.
2354 */
2355 thread_stopped(p);
2356 PROC_SUNLOCK(p);
2357 sigqueue_delete_proc(p, p->p_xsig);
2358 } else
2359 PROC_SUNLOCK(p);
2360 if (wakeup_swapper)
2361 kick_proc0();
2362 goto out;
2363 }
2364 } else {
2365 /* Not in "NORMAL" state. discard the signal. */
2366 sigqueue_delete(sigqueue, sig);
2367 goto out;
2368 }
2369
2370 /*
2371 * The process is not stopped so we need to apply the signal to all the
2372 * running threads.
2373 */
2374 runfast:
2375 tdsigwakeup(td, sig, action, intrval);
2376 PROC_SLOCK(p);
2377 thread_unsuspend(p);
2378 PROC_SUNLOCK(p);
2379 out:
2380 /* If we jump here, proc slock should not be owned. */
2381 PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
2382 return (ret);
2383 }
2384
2385 /*
2386 * The force of a signal has been directed against a single
2387 * thread. We need to see what we can do about knocking it
2388 * out of any sleep it may be in etc.
2389 */
2390 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2391 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2392 {
2393 struct proc *p = td->td_proc;
2394 int prop;
2395 int wakeup_swapper;
2396
2397 wakeup_swapper = 0;
2398 PROC_LOCK_ASSERT(p, MA_OWNED);
2399 prop = sigprop(sig);
2400
2401 PROC_SLOCK(p);
2402 thread_lock(td);
2403 /*
2404 * Bring the priority of a thread up if we want it to get
2405 * killed in this lifetime. Be careful to avoid bumping the
2406 * priority of the idle thread, since we still allow to signal
2407 * kernel processes.
2408 */
2409 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 &&
2410 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2411 sched_prio(td, PUSER);
2412 if (TD_ON_SLEEPQ(td)) {
2413 /*
2414 * If thread is sleeping uninterruptibly
2415 * we can't interrupt the sleep... the signal will
2416 * be noticed when the process returns through
2417 * trap() or syscall().
2418 */
2419 if ((td->td_flags & TDF_SINTR) == 0)
2420 goto out;
2421 /*
2422 * If SIGCONT is default (or ignored) and process is
2423 * asleep, we are finished; the process should not
2424 * be awakened.
2425 */
2426 if ((prop & SIGPROP_CONT) && action == SIG_DFL) {
2427 thread_unlock(td);
2428 PROC_SUNLOCK(p);
2429 sigqueue_delete(&p->p_sigqueue, sig);
2430 /*
2431 * It may be on either list in this state.
2432 * Remove from both for now.
2433 */
2434 sigqueue_delete(&td->td_sigqueue, sig);
2435 return;
2436 }
2437
2438 /*
2439 * Don't awaken a sleeping thread for SIGSTOP if the
2440 * STOP signal is deferred.
2441 */
2442 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2443 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2444 goto out;
2445
2446 /*
2447 * Give low priority threads a better chance to run.
2448 */
2449 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2450 sched_prio(td, PUSER);
2451
2452 wakeup_swapper = sleepq_abort(td, intrval);
2453 } else {
2454 /*
2455 * Other states do nothing with the signal immediately,
2456 * other than kicking ourselves if we are running.
2457 * It will either never be noticed, or noticed very soon.
2458 */
2459 #ifdef SMP
2460 if (TD_IS_RUNNING(td) && td != curthread)
2461 forward_signal(td);
2462 #endif
2463 }
2464 out:
2465 PROC_SUNLOCK(p);
2466 thread_unlock(td);
2467 if (wakeup_swapper)
2468 kick_proc0();
2469 }
2470
2471 static int
sig_suspend_threads(struct thread * td,struct proc * p,int sending)2472 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
2473 {
2474 struct thread *td2;
2475 int wakeup_swapper;
2476
2477 PROC_LOCK_ASSERT(p, MA_OWNED);
2478 PROC_SLOCK_ASSERT(p, MA_OWNED);
2479 MPASS(sending || td == curthread);
2480
2481 wakeup_swapper = 0;
2482 FOREACH_THREAD_IN_PROC(p, td2) {
2483 thread_lock(td2);
2484 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
2485 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
2486 (td2->td_flags & TDF_SINTR)) {
2487 if (td2->td_flags & TDF_SBDRY) {
2488 /*
2489 * Once a thread is asleep with
2490 * TDF_SBDRY and without TDF_SERESTART
2491 * or TDF_SEINTR set, it should never
2492 * become suspended due to this check.
2493 */
2494 KASSERT(!TD_IS_SUSPENDED(td2),
2495 ("thread with deferred stops suspended"));
2496 if (TD_SBDRY_INTR(td2))
2497 wakeup_swapper |= sleepq_abort(td2,
2498 TD_SBDRY_ERRNO(td2));
2499 } else if (!TD_IS_SUSPENDED(td2)) {
2500 thread_suspend_one(td2);
2501 }
2502 } else if (!TD_IS_SUSPENDED(td2)) {
2503 if (sending || td != td2)
2504 td2->td_flags |= TDF_ASTPENDING;
2505 #ifdef SMP
2506 if (TD_IS_RUNNING(td2) && td2 != td)
2507 forward_signal(td2);
2508 #endif
2509 }
2510 thread_unlock(td2);
2511 }
2512 return (wakeup_swapper);
2513 }
2514
2515 /*
2516 * Stop the process for an event deemed interesting to the debugger. If si is
2517 * non-NULL, this is a signal exchange; the new signal requested by the
2518 * debugger will be returned for handling. If si is NULL, this is some other
2519 * type of interesting event. The debugger may request a signal be delivered in
2520 * that case as well, however it will be deferred until it can be handled.
2521 */
2522 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2523 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2524 {
2525 struct proc *p = td->td_proc;
2526 struct thread *td2;
2527 ksiginfo_t ksi;
2528 int prop;
2529
2530 PROC_LOCK_ASSERT(p, MA_OWNED);
2531 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2532 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2533 &p->p_mtx.lock_object, "Stopping for traced signal");
2534
2535 td->td_xsig = sig;
2536
2537 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2538 td->td_dbgflags |= TDB_XSIG;
2539 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2540 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2541 PROC_SLOCK(p);
2542 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2543 if (P_KILLED(p)) {
2544 /*
2545 * Ensure that, if we've been PT_KILLed, the
2546 * exit status reflects that. Another thread
2547 * may also be in ptracestop(), having just
2548 * received the SIGKILL, but this thread was
2549 * unsuspended first.
2550 */
2551 td->td_dbgflags &= ~TDB_XSIG;
2552 td->td_xsig = SIGKILL;
2553 p->p_ptevents = 0;
2554 break;
2555 }
2556 if (p->p_flag & P_SINGLE_EXIT &&
2557 !(td->td_dbgflags & TDB_EXIT)) {
2558 /*
2559 * Ignore ptrace stops except for thread exit
2560 * events when the process exits.
2561 */
2562 td->td_dbgflags &= ~TDB_XSIG;
2563 PROC_SUNLOCK(p);
2564 return (0);
2565 }
2566
2567 /*
2568 * Make wait(2) work. Ensure that right after the
2569 * attach, the thread which was decided to become the
2570 * leader of attach gets reported to the waiter.
2571 * Otherwise, just avoid overwriting another thread's
2572 * assignment to p_xthread. If another thread has
2573 * already set p_xthread, the current thread will get
2574 * a chance to report itself upon the next iteration.
2575 */
2576 if ((td->td_dbgflags & TDB_FSTP) != 0 ||
2577 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
2578 p->p_xthread == NULL)) {
2579 p->p_xsig = sig;
2580 p->p_xthread = td;
2581
2582 /*
2583 * If we are on sleepqueue already,
2584 * let sleepqueue code decide if it
2585 * needs to go sleep after attach.
2586 */
2587 if (td->td_wchan == NULL)
2588 td->td_dbgflags &= ~TDB_FSTP;
2589
2590 p->p_flag2 &= ~P2_PTRACE_FSTP;
2591 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2592 sig_suspend_threads(td, p, 0);
2593 }
2594 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2595 td->td_dbgflags &= ~TDB_STOPATFORK;
2596 }
2597 stopme:
2598 thread_suspend_switch(td, p);
2599 if (p->p_xthread == td)
2600 p->p_xthread = NULL;
2601 if (!(p->p_flag & P_TRACED))
2602 break;
2603 if (td->td_dbgflags & TDB_SUSPEND) {
2604 if (p->p_flag & P_SINGLE_EXIT)
2605 break;
2606 goto stopme;
2607 }
2608 }
2609 PROC_SUNLOCK(p);
2610 }
2611
2612 if (si != NULL && sig == td->td_xsig) {
2613 /* Parent wants us to take the original signal unchanged. */
2614 si->ksi_flags |= KSI_HEAD;
2615 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2616 si->ksi_signo = 0;
2617 } else if (td->td_xsig != 0) {
2618 /*
2619 * If parent wants us to take a new signal, then it will leave
2620 * it in td->td_xsig; otherwise we just look for signals again.
2621 */
2622 ksiginfo_init(&ksi);
2623 ksi.ksi_signo = td->td_xsig;
2624 ksi.ksi_flags |= KSI_PTRACE;
2625 prop = sigprop(td->td_xsig);
2626 td2 = sigtd(p, td->td_xsig, prop);
2627 tdsendsignal(p, td2, td->td_xsig, &ksi);
2628 if (td != td2)
2629 return (0);
2630 }
2631
2632 return (td->td_xsig);
2633 }
2634
2635 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2636 reschedule_signals(struct proc *p, sigset_t block, int flags)
2637 {
2638 struct sigacts *ps;
2639 struct thread *td;
2640 int sig;
2641
2642 PROC_LOCK_ASSERT(p, MA_OWNED);
2643 ps = p->p_sigacts;
2644 mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ?
2645 MA_OWNED : MA_NOTOWNED);
2646 if (SIGISEMPTY(p->p_siglist))
2647 return;
2648 SIGSETAND(block, p->p_siglist);
2649 while ((sig = sig_ffs(&block)) != 0) {
2650 SIGDELSET(block, sig);
2651 td = sigtd(p, sig, 0);
2652 signotify(td);
2653 if (!(flags & SIGPROCMASK_PS_LOCKED))
2654 mtx_lock(&ps->ps_mtx);
2655 if (p->p_flag & P_TRACED ||
2656 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
2657 !SIGISMEMBER(td->td_sigmask, sig)))
2658 tdsigwakeup(td, sig, SIG_CATCH,
2659 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
2660 ERESTART));
2661 if (!(flags & SIGPROCMASK_PS_LOCKED))
2662 mtx_unlock(&ps->ps_mtx);
2663 }
2664 }
2665
2666 void
tdsigcleanup(struct thread * td)2667 tdsigcleanup(struct thread *td)
2668 {
2669 struct proc *p;
2670 sigset_t unblocked;
2671
2672 p = td->td_proc;
2673 PROC_LOCK_ASSERT(p, MA_OWNED);
2674
2675 sigqueue_flush(&td->td_sigqueue);
2676 if (p->p_numthreads == 1)
2677 return;
2678
2679 /*
2680 * Since we cannot handle signals, notify signal post code
2681 * about this by filling the sigmask.
2682 *
2683 * Also, if needed, wake up thread(s) that do not block the
2684 * same signals as the exiting thread, since the thread might
2685 * have been selected for delivery and woken up.
2686 */
2687 SIGFILLSET(unblocked);
2688 SIGSETNAND(unblocked, td->td_sigmask);
2689 SIGFILLSET(td->td_sigmask);
2690 reschedule_signals(p, unblocked, 0);
2691
2692 }
2693
2694 static int
sigdeferstop_curr_flags(int cflags)2695 sigdeferstop_curr_flags(int cflags)
2696 {
2697
2698 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
2699 (cflags & TDF_SBDRY) != 0);
2700 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
2701 }
2702
2703 /*
2704 * Defer the delivery of SIGSTOP for the current thread, according to
2705 * the requested mode. Returns previous flags, which must be restored
2706 * by sigallowstop().
2707 *
2708 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
2709 * cleared by the current thread, which allow the lock-less read-only
2710 * accesses below.
2711 */
2712 int
sigdeferstop_impl(int mode)2713 sigdeferstop_impl(int mode)
2714 {
2715 struct thread *td;
2716 int cflags, nflags;
2717
2718 td = curthread;
2719 cflags = sigdeferstop_curr_flags(td->td_flags);
2720 switch (mode) {
2721 case SIGDEFERSTOP_NOP:
2722 nflags = cflags;
2723 break;
2724 case SIGDEFERSTOP_OFF:
2725 nflags = 0;
2726 break;
2727 case SIGDEFERSTOP_SILENT:
2728 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
2729 break;
2730 case SIGDEFERSTOP_EINTR:
2731 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
2732 break;
2733 case SIGDEFERSTOP_ERESTART:
2734 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
2735 break;
2736 default:
2737 panic("sigdeferstop: invalid mode %x", mode);
2738 break;
2739 }
2740 if (cflags == nflags)
2741 return (SIGDEFERSTOP_VAL_NCHG);
2742 thread_lock(td);
2743 td->td_flags = (td->td_flags & ~cflags) | nflags;
2744 thread_unlock(td);
2745 return (cflags);
2746 }
2747
2748 /*
2749 * Restores the STOP handling mode, typically permitting the delivery
2750 * of SIGSTOP for the current thread. This does not immediately
2751 * suspend if a stop was posted. Instead, the thread will suspend
2752 * either via ast() or a subsequent interruptible sleep.
2753 */
2754 void
sigallowstop_impl(int prev)2755 sigallowstop_impl(int prev)
2756 {
2757 struct thread *td;
2758 int cflags;
2759
2760 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
2761 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
2762 ("sigallowstop: incorrect previous mode %x", prev));
2763 td = curthread;
2764 cflags = sigdeferstop_curr_flags(td->td_flags);
2765 if (cflags != prev) {
2766 thread_lock(td);
2767 td->td_flags = (td->td_flags & ~cflags) | prev;
2768 thread_unlock(td);
2769 }
2770 }
2771
2772 /*
2773 * If the current process has received a signal (should be caught or cause
2774 * termination, should interrupt current syscall), return the signal number.
2775 * Stop signals with default action are processed immediately, then cleared;
2776 * they aren't returned. This is checked after each entry to the system for
2777 * a syscall or trap (though this can usually be done without calling issignal
2778 * by checking the pending signal masks in cursig.) The normal call
2779 * sequence is
2780 *
2781 * while (sig = cursig(curthread))
2782 * postsig(sig);
2783 */
2784 static int
issignal(struct thread * td)2785 issignal(struct thread *td)
2786 {
2787 struct proc *p;
2788 struct sigacts *ps;
2789 struct sigqueue *queue;
2790 sigset_t sigpending;
2791 ksiginfo_t ksi;
2792 int prop, sig, traced;
2793
2794 p = td->td_proc;
2795 ps = p->p_sigacts;
2796 mtx_assert(&ps->ps_mtx, MA_OWNED);
2797 PROC_LOCK_ASSERT(p, MA_OWNED);
2798 for (;;) {
2799 traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
2800
2801 sigpending = td->td_sigqueue.sq_signals;
2802 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
2803 SIGSETNAND(sigpending, td->td_sigmask);
2804
2805 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
2806 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2807 SIG_STOPSIGMASK(sigpending);
2808 if (SIGISEMPTY(sigpending)) /* no signal to send */
2809 return (0);
2810 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
2811 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
2812 SIGISMEMBER(sigpending, SIGSTOP)) {
2813 /*
2814 * If debugger just attached, always consume
2815 * SIGSTOP from ptrace(PT_ATTACH) first, to
2816 * execute the debugger attach ritual in
2817 * order.
2818 */
2819 sig = SIGSTOP;
2820 td->td_dbgflags |= TDB_FSTP;
2821 } else {
2822 sig = sig_ffs(&sigpending);
2823 }
2824
2825 if (p->p_stops & S_SIG) {
2826 mtx_unlock(&ps->ps_mtx);
2827 stopevent(p, S_SIG, sig);
2828 mtx_lock(&ps->ps_mtx);
2829 }
2830
2831 /*
2832 * We should see pending but ignored signals
2833 * only if P_TRACED was on when they were posted.
2834 */
2835 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
2836 sigqueue_delete(&td->td_sigqueue, sig);
2837 sigqueue_delete(&p->p_sigqueue, sig);
2838 continue;
2839 }
2840 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
2841 /*
2842 * If traced, always stop.
2843 * Remove old signal from queue before the stop.
2844 * XXX shrug off debugger, it causes siginfo to
2845 * be thrown away.
2846 */
2847 queue = &td->td_sigqueue;
2848 ksiginfo_init(&ksi);
2849 if (sigqueue_get(queue, sig, &ksi) == 0) {
2850 queue = &p->p_sigqueue;
2851 sigqueue_get(queue, sig, &ksi);
2852 }
2853 td->td_si = ksi.ksi_info;
2854
2855 mtx_unlock(&ps->ps_mtx);
2856 sig = ptracestop(td, sig, &ksi);
2857 mtx_lock(&ps->ps_mtx);
2858
2859 td->td_si.si_signo = 0;
2860
2861 /*
2862 * Keep looking if the debugger discarded or
2863 * replaced the signal.
2864 */
2865 if (sig == 0)
2866 continue;
2867
2868 /*
2869 * If the signal became masked, re-queue it.
2870 */
2871 if (SIGISMEMBER(td->td_sigmask, sig)) {
2872 ksi.ksi_flags |= KSI_HEAD;
2873 sigqueue_add(&p->p_sigqueue, sig, &ksi);
2874 continue;
2875 }
2876
2877 /*
2878 * If the traced bit got turned off, requeue
2879 * the signal and go back up to the top to
2880 * rescan signals. This ensures that p_sig*
2881 * and p_sigact are consistent.
2882 */
2883 if ((p->p_flag & P_TRACED) == 0) {
2884 ksi.ksi_flags |= KSI_HEAD;
2885 sigqueue_add(queue, sig, &ksi);
2886 continue;
2887 }
2888 }
2889
2890 prop = sigprop(sig);
2891
2892 /*
2893 * Decide whether the signal should be returned.
2894 * Return the signal's number, or fall through
2895 * to clear it from the pending mask.
2896 */
2897 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2898
2899 case (intptr_t)SIG_DFL:
2900 /*
2901 * Don't take default actions on system processes.
2902 */
2903 if (p->p_pid <= 1) {
2904 #ifdef DIAGNOSTIC
2905 /*
2906 * Are you sure you want to ignore SIGSEGV
2907 * in init? XXX
2908 */
2909 printf("Process (pid %lu) got signal %d\n",
2910 (u_long)p->p_pid, sig);
2911 #endif
2912 break; /* == ignore */
2913 }
2914 /*
2915 * If there is a pending stop signal to process with
2916 * default action, stop here, then clear the signal.
2917 * Traced or exiting processes should ignore stops.
2918 * Additionally, a member of an orphaned process group
2919 * should ignore tty stops.
2920 */
2921 if (prop & SIGPROP_STOP) {
2922 if (p->p_flag &
2923 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) ||
2924 (p->p_pgrp->pg_jobc == 0 &&
2925 prop & SIGPROP_TTYSTOP))
2926 break; /* == ignore */
2927 if (TD_SBDRY_INTR(td)) {
2928 KASSERT((td->td_flags & TDF_SBDRY) != 0,
2929 ("lost TDF_SBDRY"));
2930 return (-1);
2931 }
2932 mtx_unlock(&ps->ps_mtx);
2933 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2934 &p->p_mtx.lock_object, "Catching SIGSTOP");
2935 sigqueue_delete(&td->td_sigqueue, sig);
2936 sigqueue_delete(&p->p_sigqueue, sig);
2937 p->p_flag |= P_STOPPED_SIG;
2938 p->p_xsig = sig;
2939 PROC_SLOCK(p);
2940 sig_suspend_threads(td, p, 0);
2941 thread_suspend_switch(td, p);
2942 PROC_SUNLOCK(p);
2943 mtx_lock(&ps->ps_mtx);
2944 goto next;
2945 } else if (prop & SIGPROP_IGNORE) {
2946 /*
2947 * Except for SIGCONT, shouldn't get here.
2948 * Default action is to ignore; drop it.
2949 */
2950 break; /* == ignore */
2951 } else
2952 return (sig);
2953 /*NOTREACHED*/
2954
2955 case (intptr_t)SIG_IGN:
2956 /*
2957 * Masking above should prevent us ever trying
2958 * to take action on an ignored signal other
2959 * than SIGCONT, unless process is traced.
2960 */
2961 if ((prop & SIGPROP_CONT) == 0 &&
2962 (p->p_flag & P_TRACED) == 0)
2963 printf("issignal\n");
2964 break; /* == ignore */
2965
2966 default:
2967 /*
2968 * This signal has an action, let
2969 * postsig() process it.
2970 */
2971 return (sig);
2972 }
2973 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
2974 sigqueue_delete(&p->p_sigqueue, sig);
2975 next:;
2976 }
2977 /* NOTREACHED */
2978 }
2979
2980 void
thread_stopped(struct proc * p)2981 thread_stopped(struct proc *p)
2982 {
2983 int n;
2984
2985 PROC_LOCK_ASSERT(p, MA_OWNED);
2986 PROC_SLOCK_ASSERT(p, MA_OWNED);
2987 n = p->p_suspcount;
2988 if (p == curproc)
2989 n++;
2990 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
2991 PROC_SUNLOCK(p);
2992 p->p_flag &= ~P_WAITED;
2993 PROC_LOCK(p->p_pptr);
2994 childproc_stopped(p, (p->p_flag & P_TRACED) ?
2995 CLD_TRAPPED : CLD_STOPPED);
2996 PROC_UNLOCK(p->p_pptr);
2997 PROC_SLOCK(p);
2998 }
2999 }
3000
3001 /*
3002 * Take the action for the specified signal
3003 * from the current set of pending signals.
3004 */
3005 int
postsig(int sig)3006 postsig(int sig)
3007 {
3008 struct thread *td;
3009 struct proc *p;
3010 struct sigacts *ps;
3011 sig_t action;
3012 ksiginfo_t ksi;
3013 sigset_t returnmask;
3014
3015 KASSERT(sig != 0, ("postsig"));
3016
3017 td = curthread;
3018 p = td->td_proc;
3019 PROC_LOCK_ASSERT(p, MA_OWNED);
3020 ps = p->p_sigacts;
3021 mtx_assert(&ps->ps_mtx, MA_OWNED);
3022 ksiginfo_init(&ksi);
3023 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3024 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3025 return (0);
3026 ksi.ksi_signo = sig;
3027 if (ksi.ksi_code == SI_TIMER)
3028 itimer_accept(p, ksi.ksi_timerid, &ksi);
3029 action = ps->ps_sigact[_SIG_IDX(sig)];
3030 #ifdef KTRACE
3031 if (KTRPOINT(td, KTR_PSIG))
3032 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3033 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3034 #endif
3035 if ((p->p_stops & S_SIG) != 0) {
3036 mtx_unlock(&ps->ps_mtx);
3037 stopevent(p, S_SIG, sig);
3038 mtx_lock(&ps->ps_mtx);
3039 }
3040
3041 if (action == SIG_DFL) {
3042 /*
3043 * Default action, where the default is to kill
3044 * the process. (Other cases were ignored above.)
3045 */
3046 mtx_unlock(&ps->ps_mtx);
3047 proc_td_siginfo_capture(td, &ksi.ksi_info);
3048 sigexit(td, sig);
3049 /* NOTREACHED */
3050 } else {
3051 /*
3052 * If we get here, the signal must be caught.
3053 */
3054 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3055 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3056 ("postsig action: blocked sig %d", sig));
3057
3058 /*
3059 * Set the new mask value and also defer further
3060 * occurrences of this signal.
3061 *
3062 * Special case: user has done a sigsuspend. Here the
3063 * current mask is not of interest, but rather the
3064 * mask from before the sigsuspend is what we want
3065 * restored after the signal processing is completed.
3066 */
3067 if (td->td_pflags & TDP_OLDMASK) {
3068 returnmask = td->td_oldsigmask;
3069 td->td_pflags &= ~TDP_OLDMASK;
3070 } else
3071 returnmask = td->td_sigmask;
3072
3073 if (p->p_sig == sig) {
3074 p->p_code = 0;
3075 p->p_sig = 0;
3076 }
3077 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3078 postsig_done(sig, td, ps);
3079 }
3080 return (1);
3081 }
3082
3083 void
proc_wkilled(struct proc * p)3084 proc_wkilled(struct proc *p)
3085 {
3086
3087 PROC_LOCK_ASSERT(p, MA_OWNED);
3088 if ((p->p_flag & P_WKILLED) == 0) {
3089 p->p_flag |= P_WKILLED;
3090 /*
3091 * Notify swapper that there is a process to swap in.
3092 * The notification is racy, at worst it would take 10
3093 * seconds for the swapper process to notice.
3094 */
3095 if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0)
3096 wakeup(&proc0);
3097 }
3098 }
3099
3100 /*
3101 * Kill the current process for stated reason.
3102 */
3103 void
killproc(struct proc * p,char * why)3104 killproc(struct proc *p, char *why)
3105 {
3106
3107 PROC_LOCK_ASSERT(p, MA_OWNED);
3108 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3109 p->p_comm);
3110 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
3111 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
3112 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
3113 proc_wkilled(p);
3114 kern_psignal(p, SIGKILL);
3115 }
3116
3117 /*
3118 * Force the current process to exit with the specified signal, dumping core
3119 * if appropriate. We bypass the normal tests for masked and caught signals,
3120 * allowing unrecoverable failures to terminate the process without changing
3121 * signal state. Mark the accounting record with the signal termination.
3122 * If dumping core, save the signal number for the debugger. Calls exit and
3123 * does not return.
3124 */
3125 void
sigexit(struct thread * td,int sig)3126 sigexit(struct thread *td, int sig)
3127 {
3128 struct proc *p = td->td_proc;
3129
3130 PROC_LOCK_ASSERT(p, MA_OWNED);
3131 p->p_acflag |= AXSIG;
3132 /*
3133 * We must be single-threading to generate a core dump. This
3134 * ensures that the registers in the core file are up-to-date.
3135 * Also, the ELF dump handler assumes that the thread list doesn't
3136 * change out from under it.
3137 *
3138 * XXX If another thread attempts to single-thread before us
3139 * (e.g. via fork()), we won't get a dump at all.
3140 */
3141 if ((sigprop(sig) & SIGPROP_CORE) &&
3142 thread_single(p, SINGLE_NO_EXIT) == 0) {
3143 p->p_sig = sig;
3144 /*
3145 * Log signals which would cause core dumps
3146 * (Log as LOG_INFO to appease those who don't want
3147 * these messages.)
3148 * XXX : Todo, as well as euid, write out ruid too
3149 * Note that coredump() drops proc lock.
3150 */
3151 if (coredump(td) == 0)
3152 sig |= WCOREFLAG;
3153 if (kern_logsigexit)
3154 log(LOG_INFO,
3155 "pid %d (%s), jid %d, uid %d: exited on "
3156 "signal %d%s\n", p->p_pid, p->p_comm,
3157 p->p_ucred->cr_prison->pr_id,
3158 td->td_ucred ? td->td_ucred->cr_uid : -1,
3159 sig &~ WCOREFLAG,
3160 sig & WCOREFLAG ? " (core dumped)" : "");
3161 } else
3162 PROC_UNLOCK(p);
3163 exit1(td, 0, sig);
3164 /* NOTREACHED */
3165 }
3166
3167 /*
3168 * Send queued SIGCHLD to parent when child process's state
3169 * is changed.
3170 */
3171 static void
sigparent(struct proc * p,int reason,int status)3172 sigparent(struct proc *p, int reason, int status)
3173 {
3174 PROC_LOCK_ASSERT(p, MA_OWNED);
3175 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3176
3177 if (p->p_ksi != NULL) {
3178 p->p_ksi->ksi_signo = SIGCHLD;
3179 p->p_ksi->ksi_code = reason;
3180 p->p_ksi->ksi_status = status;
3181 p->p_ksi->ksi_pid = p->p_pid;
3182 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3183 if (KSI_ONQ(p->p_ksi))
3184 return;
3185 }
3186 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3187 }
3188
3189 static void
childproc_jobstate(struct proc * p,int reason,int sig)3190 childproc_jobstate(struct proc *p, int reason, int sig)
3191 {
3192 struct sigacts *ps;
3193
3194 PROC_LOCK_ASSERT(p, MA_OWNED);
3195 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3196
3197 /*
3198 * Wake up parent sleeping in kern_wait(), also send
3199 * SIGCHLD to parent, but SIGCHLD does not guarantee
3200 * that parent will awake, because parent may masked
3201 * the signal.
3202 */
3203 p->p_pptr->p_flag |= P_STATCHILD;
3204 wakeup(p->p_pptr);
3205
3206 ps = p->p_pptr->p_sigacts;
3207 mtx_lock(&ps->ps_mtx);
3208 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3209 mtx_unlock(&ps->ps_mtx);
3210 sigparent(p, reason, sig);
3211 } else
3212 mtx_unlock(&ps->ps_mtx);
3213 }
3214
3215 void
childproc_stopped(struct proc * p,int reason)3216 childproc_stopped(struct proc *p, int reason)
3217 {
3218
3219 childproc_jobstate(p, reason, p->p_xsig);
3220 }
3221
3222 void
childproc_continued(struct proc * p)3223 childproc_continued(struct proc *p)
3224 {
3225 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3226 }
3227
3228 void
childproc_exited(struct proc * p)3229 childproc_exited(struct proc *p)
3230 {
3231 int reason, status;
3232
3233 if (WCOREDUMP(p->p_xsig)) {
3234 reason = CLD_DUMPED;
3235 status = WTERMSIG(p->p_xsig);
3236 } else if (WIFSIGNALED(p->p_xsig)) {
3237 reason = CLD_KILLED;
3238 status = WTERMSIG(p->p_xsig);
3239 } else {
3240 reason = CLD_EXITED;
3241 status = p->p_xexit;
3242 }
3243 /*
3244 * XXX avoid calling wakeup(p->p_pptr), the work is
3245 * done in exit1().
3246 */
3247 sigparent(p, reason, status);
3248 }
3249
3250 #define MAX_NUM_CORE_FILES 100000
3251 #ifndef NUM_CORE_FILES
3252 #define NUM_CORE_FILES 5
3253 #endif
3254 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES);
3255 static int num_cores = NUM_CORE_FILES;
3256
3257 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3258 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3259 {
3260 int error;
3261 int new_val;
3262
3263 new_val = num_cores;
3264 error = sysctl_handle_int(oidp, &new_val, 0, req);
3265 if (error != 0 || req->newptr == NULL)
3266 return (error);
3267 if (new_val > MAX_NUM_CORE_FILES)
3268 new_val = MAX_NUM_CORE_FILES;
3269 if (new_val < 0)
3270 new_val = 0;
3271 num_cores = new_val;
3272 return (0);
3273 }
3274 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
3275 0, sizeof(int), sysctl_debug_num_cores_check, "I",
3276 "Maximum number of generated process corefiles while using index format");
3277
3278 #define GZIP_SUFFIX ".gz"
3279 #define ZSTD_SUFFIX ".zst"
3280
3281 int compress_user_cores = 0;
3282
3283 static int
sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)3284 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)
3285 {
3286 int error, val;
3287
3288 val = compress_user_cores;
3289 error = sysctl_handle_int(oidp, &val, 0, req);
3290 if (error != 0 || req->newptr == NULL)
3291 return (error);
3292 if (val != 0 && !compressor_avail(val))
3293 return (EINVAL);
3294 compress_user_cores = val;
3295 return (error);
3296 }
3297 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores, CTLTYPE_INT | CTLFLAG_RWTUN,
3298 0, sizeof(int), sysctl_compress_user_cores, "I",
3299 "Enable compression of user corefiles ("
3300 __XSTRING(COMPRESS_GZIP) " = gzip, "
3301 __XSTRING(COMPRESS_ZSTD) " = zstd)");
3302
3303 int compress_user_cores_level = 6;
3304 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN,
3305 &compress_user_cores_level, 0,
3306 "Corefile compression level");
3307
3308 /*
3309 * Protect the access to corefilename[] by allproc_lock.
3310 */
3311 #define corefilename_lock allproc_lock
3312
3313 static char corefilename[MAXPATHLEN] = {"%N.core"};
3314 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3315
3316 static int
sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)3317 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
3318 {
3319 int error;
3320
3321 sx_xlock(&corefilename_lock);
3322 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
3323 req);
3324 sx_xunlock(&corefilename_lock);
3325
3326 return (error);
3327 }
3328 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
3329 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
3330 "Process corefile name format string");
3331
3332 static void
vnode_close_locked(struct thread * td,struct vnode * vp)3333 vnode_close_locked(struct thread *td, struct vnode *vp)
3334 {
3335
3336 VOP_UNLOCK(vp, 0);
3337 vn_close(vp, FWRITE, td->td_ucred, td);
3338 }
3339
3340 /*
3341 * If the core format has a %I in it, then we need to check
3342 * for existing corefiles before defining a name.
3343 * To do this we iterate over 0..ncores to find a
3344 * non-existing core file name to use. If all core files are
3345 * already used we choose the oldest one.
3346 */
3347 static int
corefile_open_last(struct thread * td,char * name,int indexpos,int indexlen,int ncores,struct vnode ** vpp)3348 corefile_open_last(struct thread *td, char *name, int indexpos,
3349 int indexlen, int ncores, struct vnode **vpp)
3350 {
3351 struct vnode *oldvp, *nextvp, *vp;
3352 struct vattr vattr;
3353 struct nameidata nd;
3354 int error, i, flags, oflags, cmode;
3355 char ch;
3356 struct timespec lasttime;
3357
3358 nextvp = oldvp = NULL;
3359 cmode = S_IRUSR | S_IWUSR;
3360 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3361 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3362
3363 for (i = 0; i < ncores; i++) {
3364 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3365
3366 ch = name[indexpos + indexlen];
3367 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen,
3368 i);
3369 name[indexpos + indexlen] = ch;
3370
3371 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3372 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3373 NULL);
3374 if (error != 0)
3375 break;
3376
3377 vp = nd.ni_vp;
3378 NDFREE(&nd, NDF_ONLY_PNBUF);
3379 if ((flags & O_CREAT) == O_CREAT) {
3380 nextvp = vp;
3381 break;
3382 }
3383
3384 error = VOP_GETATTR(vp, &vattr, td->td_ucred);
3385 if (error != 0) {
3386 vnode_close_locked(td, vp);
3387 break;
3388 }
3389
3390 if (oldvp == NULL ||
3391 lasttime.tv_sec > vattr.va_mtime.tv_sec ||
3392 (lasttime.tv_sec == vattr.va_mtime.tv_sec &&
3393 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) {
3394 if (oldvp != NULL)
3395 vnode_close_locked(td, oldvp);
3396 oldvp = vp;
3397 lasttime = vattr.va_mtime;
3398 } else {
3399 vnode_close_locked(td, vp);
3400 }
3401 }
3402
3403 if (oldvp != NULL) {
3404 if (nextvp == NULL) {
3405 if ((td->td_proc->p_flag & P_SUGID) != 0) {
3406 error = EFAULT;
3407 vnode_close_locked(td, oldvp);
3408 } else {
3409 nextvp = oldvp;
3410 }
3411 } else {
3412 vnode_close_locked(td, oldvp);
3413 }
3414 }
3415 if (error != 0) {
3416 if (nextvp != NULL)
3417 vnode_close_locked(td, oldvp);
3418 } else {
3419 *vpp = nextvp;
3420 }
3421
3422 return (error);
3423 }
3424
3425 /*
3426 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3427 * Expand the name described in corefilename, using name, uid, and pid
3428 * and open/create core file.
3429 * corefilename is a printf-like string, with three format specifiers:
3430 * %N name of process ("name")
3431 * %P process id (pid)
3432 * %U user id (uid)
3433 * For example, "%N.core" is the default; they can be disabled completely
3434 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3435 * This is controlled by the sysctl variable kern.corefile (see above).
3436 */
3437 static int
corefile_open(const char * comm,uid_t uid,pid_t pid,struct thread * td,int compress,struct vnode ** vpp,char ** namep)3438 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
3439 int compress, struct vnode **vpp, char **namep)
3440 {
3441 struct sbuf sb;
3442 struct nameidata nd;
3443 const char *format;
3444 char *hostname, *name;
3445 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores;
3446
3447 hostname = NULL;
3448 format = corefilename;
3449 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
3450 indexlen = 0;
3451 indexpos = -1;
3452 ncores = num_cores;
3453 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
3454 sx_slock(&corefilename_lock);
3455 for (i = 0; format[i] != '\0'; i++) {
3456 switch (format[i]) {
3457 case '%': /* Format character */
3458 i++;
3459 switch (format[i]) {
3460 case '%':
3461 sbuf_putc(&sb, '%');
3462 break;
3463 case 'H': /* hostname */
3464 if (hostname == NULL) {
3465 hostname = malloc(MAXHOSTNAMELEN,
3466 M_TEMP, M_WAITOK);
3467 }
3468 getcredhostname(td->td_ucred, hostname,
3469 MAXHOSTNAMELEN);
3470 sbuf_printf(&sb, "%s", hostname);
3471 break;
3472 case 'I': /* autoincrementing index */
3473 if (indexpos != -1) {
3474 sbuf_printf(&sb, "%%I");
3475 break;
3476 }
3477
3478 indexpos = sbuf_len(&sb);
3479 sbuf_printf(&sb, "%u", ncores - 1);
3480 indexlen = sbuf_len(&sb) - indexpos;
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 == COMPRESS_GZIP)
3506 sbuf_printf(&sb, GZIP_SUFFIX);
3507 else if (compress == COMPRESS_ZSTD)
3508 sbuf_printf(&sb, ZSTD_SUFFIX);
3509 if (sbuf_error(&sb) != 0) {
3510 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
3511 "long\n", (long)pid, comm, (u_long)uid);
3512 sbuf_delete(&sb);
3513 free(name, M_TEMP);
3514 return (ENOMEM);
3515 }
3516 sbuf_finish(&sb);
3517 sbuf_delete(&sb);
3518
3519 if (indexpos != -1) {
3520 error = corefile_open_last(td, name, indexpos, indexlen, ncores,
3521 vpp);
3522 if (error != 0) {
3523 log(LOG_ERR,
3524 "pid %d (%s), uid (%u): Path `%s' failed "
3525 "on initial open test, error = %d\n",
3526 pid, comm, uid, name, error);
3527 }
3528 } else {
3529 cmode = S_IRUSR | S_IWUSR;
3530 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3531 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3532 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3533 if ((td->td_proc->p_flag & P_SUGID) != 0)
3534 flags |= O_EXCL;
3535
3536 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3537 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3538 NULL);
3539 if (error == 0) {
3540 *vpp = nd.ni_vp;
3541 NDFREE(&nd, NDF_ONLY_PNBUF);
3542 }
3543 }
3544
3545 if (error != 0) {
3546 #ifdef AUDIT
3547 audit_proc_coredump(td, name, error);
3548 #endif
3549 free(name, M_TEMP);
3550 return (error);
3551 }
3552 *namep = name;
3553 return (0);
3554 }
3555
3556 /*
3557 * Dump a process' core. The main routine does some
3558 * policy checking, and creates the name of the coredump;
3559 * then it passes on a vnode and a size limit to the process-specific
3560 * coredump routine if there is one; if there _is not_ one, it returns
3561 * ENOSYS; otherwise it returns the error from the process-specific routine.
3562 */
3563
3564 static int
coredump(struct thread * td)3565 coredump(struct thread *td)
3566 {
3567 struct proc *p = td->td_proc;
3568 struct ucred *cred = td->td_ucred;
3569 struct vnode *vp;
3570 struct flock lf;
3571 struct vattr vattr;
3572 int error, error1, locked;
3573 char *name; /* name of corefile */
3574 void *rl_cookie;
3575 off_t limit;
3576 char *fullpath, *freepath = NULL;
3577 struct sbuf *sb;
3578
3579 PROC_LOCK_ASSERT(p, MA_OWNED);
3580 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
3581 _STOPEVENT(p, S_CORE, 0);
3582
3583 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
3584 (p->p_flag2 & P2_NOTRACE) != 0) {
3585 PROC_UNLOCK(p);
3586 return (EFAULT);
3587 }
3588
3589 /*
3590 * Note that the bulk of limit checking is done after
3591 * the corefile is created. The exception is if the limit
3592 * for corefiles is 0, in which case we don't bother
3593 * creating the corefile at all. This layout means that
3594 * a corefile is truncated instead of not being created,
3595 * if it is larger than the limit.
3596 */
3597 limit = (off_t)lim_cur(td, RLIMIT_CORE);
3598 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
3599 PROC_UNLOCK(p);
3600 return (EFBIG);
3601 }
3602 PROC_UNLOCK(p);
3603
3604 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
3605 compress_user_cores, &vp, &name);
3606 if (error != 0)
3607 return (error);
3608
3609 /*
3610 * Don't dump to non-regular files or files with links.
3611 * Do not dump into system files. Effective user must own the corefile.
3612 */
3613 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
3614 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 ||
3615 vattr.va_uid != cred->cr_uid) {
3616 VOP_UNLOCK(vp, 0);
3617 error = EFAULT;
3618 goto out;
3619 }
3620
3621 VOP_UNLOCK(vp, 0);
3622
3623 /* Postpone other writers, including core dumps of other processes. */
3624 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
3625
3626 lf.l_whence = SEEK_SET;
3627 lf.l_start = 0;
3628 lf.l_len = 0;
3629 lf.l_type = F_WRLCK;
3630 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
3631
3632 VATTR_NULL(&vattr);
3633 vattr.va_size = 0;
3634 if (set_core_nodump_flag)
3635 vattr.va_flags = UF_NODUMP;
3636 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3637 VOP_SETATTR(vp, &vattr, cred);
3638 VOP_UNLOCK(vp, 0);
3639 PROC_LOCK(p);
3640 p->p_acflag |= ACORE;
3641 PROC_UNLOCK(p);
3642
3643 if (p->p_sysent->sv_coredump != NULL) {
3644 error = p->p_sysent->sv_coredump(td, vp, limit, 0);
3645 } else {
3646 error = ENOSYS;
3647 }
3648
3649 if (locked) {
3650 lf.l_type = F_UNLCK;
3651 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3652 }
3653 vn_rangelock_unlock(vp, rl_cookie);
3654
3655 /*
3656 * Notify the userland helper that a process triggered a core dump.
3657 * This allows the helper to run an automated debugging session.
3658 */
3659 if (error != 0 || coredump_devctl == 0)
3660 goto out;
3661 sb = sbuf_new_auto();
3662 if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
3663 goto out2;
3664 sbuf_printf(sb, "comm=\"");
3665 devctl_safe_quote_sb(sb, fullpath);
3666 free(freepath, M_TEMP);
3667 sbuf_printf(sb, "\" core=\"");
3668
3669 /*
3670 * We can't lookup core file vp directly. When we're replacing a core, and
3671 * other random times, we flush the name cache, so it will fail. Instead,
3672 * if the path of the core is relative, add the current dir in front if it.
3673 */
3674 if (name[0] != '/') {
3675 fullpath = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
3676 if (kern___getcwd(td, fullpath, UIO_SYSSPACE, MAXPATHLEN, MAXPATHLEN) != 0) {
3677 free(fullpath, M_TEMP);
3678 goto out2;
3679 }
3680 devctl_safe_quote_sb(sb, fullpath);
3681 free(fullpath, M_TEMP);
3682 sbuf_putc(sb, '/');
3683 }
3684 devctl_safe_quote_sb(sb, name);
3685 sbuf_printf(sb, "\"");
3686 if (sbuf_finish(sb) == 0)
3687 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb));
3688 out2:
3689 sbuf_delete(sb);
3690 out:
3691 error1 = vn_close(vp, FWRITE, cred, td);
3692 if (error == 0)
3693 error = error1;
3694 #ifdef AUDIT
3695 audit_proc_coredump(td, name, error);
3696 #endif
3697 free(name, M_TEMP);
3698 return (error);
3699 }
3700
3701 /*
3702 * Nonexistent system call-- signal process (may want to handle it). Flag
3703 * error in case process won't see signal immediately (blocked or ignored).
3704 */
3705 #ifndef _SYS_SYSPROTO_H_
3706 struct nosys_args {
3707 int dummy;
3708 };
3709 #endif
3710 /* ARGSUSED */
3711 int
nosys(struct thread * td,struct nosys_args * args)3712 nosys(struct thread *td, struct nosys_args *args)
3713 {
3714 struct proc *p;
3715
3716 p = td->td_proc;
3717
3718 PROC_LOCK(p);
3719 tdsignal(td, SIGSYS);
3720 PROC_UNLOCK(p);
3721 if (kern_lognosys == 1 || kern_lognosys == 3) {
3722 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3723 td->td_sa.code);
3724 }
3725 if (kern_lognosys == 2 || kern_lognosys == 3) {
3726 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3727 td->td_sa.code);
3728 }
3729 return (ENOSYS);
3730 }
3731
3732 /*
3733 * Send a SIGIO or SIGURG signal to a process or process group using stored
3734 * credentials rather than those of the current process.
3735 */
3736 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)3737 pgsigio(struct sigio **sigiop, int sig, int checkctty)
3738 {
3739 ksiginfo_t ksi;
3740 struct sigio *sigio;
3741
3742 ksiginfo_init(&ksi);
3743 ksi.ksi_signo = sig;
3744 ksi.ksi_code = SI_KERNEL;
3745
3746 SIGIO_LOCK();
3747 sigio = *sigiop;
3748 if (sigio == NULL) {
3749 SIGIO_UNLOCK();
3750 return;
3751 }
3752 if (sigio->sio_pgid > 0) {
3753 PROC_LOCK(sigio->sio_proc);
3754 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3755 kern_psignal(sigio->sio_proc, sig);
3756 PROC_UNLOCK(sigio->sio_proc);
3757 } else if (sigio->sio_pgid < 0) {
3758 struct proc *p;
3759
3760 PGRP_LOCK(sigio->sio_pgrp);
3761 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3762 PROC_LOCK(p);
3763 if (p->p_state == PRS_NORMAL &&
3764 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3765 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3766 kern_psignal(p, sig);
3767 PROC_UNLOCK(p);
3768 }
3769 PGRP_UNLOCK(sigio->sio_pgrp);
3770 }
3771 SIGIO_UNLOCK();
3772 }
3773
3774 static int
filt_sigattach(struct knote * kn)3775 filt_sigattach(struct knote *kn)
3776 {
3777 struct proc *p = curproc;
3778
3779 kn->kn_ptr.p_proc = p;
3780 kn->kn_flags |= EV_CLEAR; /* automatically set */
3781
3782 knlist_add(p->p_klist, kn, 0);
3783
3784 return (0);
3785 }
3786
3787 static void
filt_sigdetach(struct knote * kn)3788 filt_sigdetach(struct knote *kn)
3789 {
3790 struct proc *p = kn->kn_ptr.p_proc;
3791
3792 knlist_remove(p->p_klist, kn, 0);
3793 }
3794
3795 /*
3796 * signal knotes are shared with proc knotes, so we apply a mask to
3797 * the hint in order to differentiate them from process hints. This
3798 * could be avoided by using a signal-specific knote list, but probably
3799 * isn't worth the trouble.
3800 */
3801 static int
filt_signal(struct knote * kn,long hint)3802 filt_signal(struct knote *kn, long hint)
3803 {
3804
3805 if (hint & NOTE_SIGNAL) {
3806 hint &= ~NOTE_SIGNAL;
3807
3808 if (kn->kn_id == hint)
3809 kn->kn_data++;
3810 }
3811 return (kn->kn_data != 0);
3812 }
3813
3814 struct sigacts *
sigacts_alloc(void)3815 sigacts_alloc(void)
3816 {
3817 struct sigacts *ps;
3818
3819 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3820 refcount_init(&ps->ps_refcnt, 1);
3821 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3822 return (ps);
3823 }
3824
3825 void
sigacts_free(struct sigacts * ps)3826 sigacts_free(struct sigacts *ps)
3827 {
3828
3829 if (refcount_release(&ps->ps_refcnt) == 0)
3830 return;
3831 mtx_destroy(&ps->ps_mtx);
3832 free(ps, M_SUBPROC);
3833 }
3834
3835 struct sigacts *
sigacts_hold(struct sigacts * ps)3836 sigacts_hold(struct sigacts *ps)
3837 {
3838
3839 refcount_acquire(&ps->ps_refcnt);
3840 return (ps);
3841 }
3842
3843 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3844 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3845 {
3846
3847 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3848 mtx_lock(&src->ps_mtx);
3849 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3850 mtx_unlock(&src->ps_mtx);
3851 }
3852
3853 int
sigacts_shared(struct sigacts * ps)3854 sigacts_shared(struct sigacts *ps)
3855 {
3856
3857 return (ps->ps_refcnt > 1);
3858 }
3859