1 /*-
2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD: stable/10/sys/kern/kern_sig.c 342704 2019-01-02 19:11:49Z jhb $");
39
40 #include "opt_compat.h"
41 #include "opt_kdtrace.h"
42 #include "opt_ktrace.h"
43 #include "opt_core.h"
44 #include "opt_procdesc.h"
45
46 #include <sys/param.h>
47 #include <sys/ctype.h>
48 #include <sys/systm.h>
49 #include <sys/signalvar.h>
50 #include <sys/vnode.h>
51 #include <sys/acct.h>
52 #include <sys/bus.h>
53 #include <sys/capsicum.h>
54 #include <sys/condvar.h>
55 #include <sys/event.h>
56 #include <sys/fcntl.h>
57 #include <sys/imgact.h>
58 #include <sys/kernel.h>
59 #include <sys/ktr.h>
60 #include <sys/ktrace.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 void 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 TUNABLE_INT("kern.sigqueue.preallocate", &preallocate_siginfo);
145 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RD,
146 &preallocate_siginfo, 0, "Preallocated signal memory size");
147
148 static int signal_overflow = 0;
149 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
150 &signal_overflow, 0, "Number of signals overflew");
151
152 static int signal_alloc_fail = 0;
153 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
154 &signal_alloc_fail, 0, "signals failed to be allocated");
155
156 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
157
158 /*
159 * Policy -- Can ucred cr1 send SIGIO to process cr2?
160 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
161 * in the right situations.
162 */
163 #define CANSIGIO(cr1, cr2) \
164 ((cr1)->cr_uid == 0 || \
165 (cr1)->cr_ruid == (cr2)->cr_ruid || \
166 (cr1)->cr_uid == (cr2)->cr_ruid || \
167 (cr1)->cr_ruid == (cr2)->cr_uid || \
168 (cr1)->cr_uid == (cr2)->cr_uid)
169
170 static int sugid_coredump;
171 TUNABLE_INT("kern.sugid_coredump", &sugid_coredump);
172 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
173 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
174
175 static int capmode_coredump;
176 TUNABLE_INT("kern.capmode_coredump", &capmode_coredump);
177 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RW,
178 &capmode_coredump, 0, "Allow processes in capability mode to dump core");
179
180 static int do_coredump = 1;
181 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
182 &do_coredump, 0, "Enable/Disable coredumps");
183
184 static int set_core_nodump_flag = 0;
185 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
186 0, "Enable setting the NODUMP flag on coredump files");
187
188 static int coredump_devctl = 0;
189 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
190 0, "Generate a devctl notification when processes coredump");
191
192 /*
193 * Signal properties and actions.
194 * The array below categorizes the signals and their default actions
195 * according to the following properties:
196 */
197 #define SA_KILL 0x01 /* terminates process by default */
198 #define SA_CORE 0x02 /* ditto and coredumps */
199 #define SA_STOP 0x04 /* suspend process */
200 #define SA_TTYSTOP 0x08 /* ditto, from tty */
201 #define SA_IGNORE 0x10 /* ignore by default */
202 #define SA_CONT 0x20 /* continue if suspended */
203 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
204
205 static int sigproptbl[NSIG] = {
206 SA_KILL, /* SIGHUP */
207 SA_KILL, /* SIGINT */
208 SA_KILL|SA_CORE, /* SIGQUIT */
209 SA_KILL|SA_CORE, /* SIGILL */
210 SA_KILL|SA_CORE, /* SIGTRAP */
211 SA_KILL|SA_CORE, /* SIGABRT */
212 SA_KILL|SA_CORE, /* SIGEMT */
213 SA_KILL|SA_CORE, /* SIGFPE */
214 SA_KILL, /* SIGKILL */
215 SA_KILL|SA_CORE, /* SIGBUS */
216 SA_KILL|SA_CORE, /* SIGSEGV */
217 SA_KILL|SA_CORE, /* SIGSYS */
218 SA_KILL, /* SIGPIPE */
219 SA_KILL, /* SIGALRM */
220 SA_KILL, /* SIGTERM */
221 SA_IGNORE, /* SIGURG */
222 SA_STOP, /* SIGSTOP */
223 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
224 SA_IGNORE|SA_CONT, /* SIGCONT */
225 SA_IGNORE, /* SIGCHLD */
226 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
227 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
228 SA_IGNORE, /* SIGIO */
229 SA_KILL, /* SIGXCPU */
230 SA_KILL, /* SIGXFSZ */
231 SA_KILL, /* SIGVTALRM */
232 SA_KILL, /* SIGPROF */
233 SA_IGNORE, /* SIGWINCH */
234 SA_IGNORE, /* SIGINFO */
235 SA_KILL, /* SIGUSR1 */
236 SA_KILL, /* SIGUSR2 */
237 };
238
239 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
240
241 static void
sigqueue_start(void)242 sigqueue_start(void)
243 {
244 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
245 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
246 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
247 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
248 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
249 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
250 }
251
252 ksiginfo_t *
ksiginfo_alloc(int wait)253 ksiginfo_alloc(int wait)
254 {
255 int flags;
256
257 flags = M_ZERO;
258 if (! wait)
259 flags |= M_NOWAIT;
260 if (ksiginfo_zone != NULL)
261 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
262 return (NULL);
263 }
264
265 void
ksiginfo_free(ksiginfo_t * ksi)266 ksiginfo_free(ksiginfo_t *ksi)
267 {
268 uma_zfree(ksiginfo_zone, ksi);
269 }
270
271 static __inline int
ksiginfo_tryfree(ksiginfo_t * ksi)272 ksiginfo_tryfree(ksiginfo_t *ksi)
273 {
274 if (!(ksi->ksi_flags & KSI_EXT)) {
275 uma_zfree(ksiginfo_zone, ksi);
276 return (1);
277 }
278 return (0);
279 }
280
281 void
sigqueue_init(sigqueue_t * list,struct proc * p)282 sigqueue_init(sigqueue_t *list, struct proc *p)
283 {
284 SIGEMPTYSET(list->sq_signals);
285 SIGEMPTYSET(list->sq_kill);
286 SIGEMPTYSET(list->sq_ptrace);
287 TAILQ_INIT(&list->sq_list);
288 list->sq_proc = p;
289 list->sq_flags = SQ_INIT;
290 }
291
292 /*
293 * Get a signal's ksiginfo.
294 * Return:
295 * 0 - signal not found
296 * others - signal number
297 */
298 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)299 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
300 {
301 struct proc *p = sq->sq_proc;
302 struct ksiginfo *ksi, *next;
303 int count = 0;
304
305 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
306
307 if (!SIGISMEMBER(sq->sq_signals, signo))
308 return (0);
309
310 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
311 count++;
312 SIGDELSET(sq->sq_ptrace, signo);
313 si->ksi_flags |= KSI_PTRACE;
314 }
315 if (SIGISMEMBER(sq->sq_kill, signo)) {
316 count++;
317 if (count == 1)
318 SIGDELSET(sq->sq_kill, signo);
319 }
320
321 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
322 if (ksi->ksi_signo == signo) {
323 if (count == 0) {
324 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
325 ksi->ksi_sigq = NULL;
326 ksiginfo_copy(ksi, si);
327 if (ksiginfo_tryfree(ksi) && p != NULL)
328 p->p_pendingcnt--;
329 }
330 if (++count > 1)
331 break;
332 }
333 }
334
335 if (count <= 1)
336 SIGDELSET(sq->sq_signals, signo);
337 si->ksi_signo = signo;
338 return (signo);
339 }
340
341 void
sigqueue_take(ksiginfo_t * ksi)342 sigqueue_take(ksiginfo_t *ksi)
343 {
344 struct ksiginfo *kp;
345 struct proc *p;
346 sigqueue_t *sq;
347
348 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
349 return;
350
351 p = sq->sq_proc;
352 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
353 ksi->ksi_sigq = NULL;
354 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
355 p->p_pendingcnt--;
356
357 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
358 kp = TAILQ_NEXT(kp, ksi_link)) {
359 if (kp->ksi_signo == ksi->ksi_signo)
360 break;
361 }
362 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
363 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
364 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
365 }
366
367 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)368 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
369 {
370 struct proc *p = sq->sq_proc;
371 struct ksiginfo *ksi;
372 int ret = 0;
373
374 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
375
376 /*
377 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
378 * for these signals.
379 */
380 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
381 SIGADDSET(sq->sq_kill, signo);
382 goto out_set_bit;
383 }
384
385 /* directly insert the ksi, don't copy it */
386 if (si->ksi_flags & KSI_INS) {
387 if (si->ksi_flags & KSI_HEAD)
388 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
389 else
390 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
391 si->ksi_sigq = sq;
392 goto out_set_bit;
393 }
394
395 if (__predict_false(ksiginfo_zone == NULL)) {
396 SIGADDSET(sq->sq_kill, signo);
397 goto out_set_bit;
398 }
399
400 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
401 signal_overflow++;
402 ret = EAGAIN;
403 } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
404 signal_alloc_fail++;
405 ret = EAGAIN;
406 } else {
407 if (p != NULL)
408 p->p_pendingcnt++;
409 ksiginfo_copy(si, ksi);
410 ksi->ksi_signo = signo;
411 if (si->ksi_flags & KSI_HEAD)
412 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
413 else
414 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
415 ksi->ksi_sigq = sq;
416 }
417
418 if (ret != 0) {
419 if ((si->ksi_flags & KSI_PTRACE) != 0) {
420 SIGADDSET(sq->sq_ptrace, signo);
421 ret = 0;
422 goto out_set_bit;
423 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
424 (si->ksi_flags & KSI_SIGQ) == 0) {
425 SIGADDSET(sq->sq_kill, signo);
426 ret = 0;
427 goto out_set_bit;
428 }
429 return (ret);
430 }
431
432 out_set_bit:
433 SIGADDSET(sq->sq_signals, signo);
434 return (ret);
435 }
436
437 void
sigqueue_flush(sigqueue_t * sq)438 sigqueue_flush(sigqueue_t *sq)
439 {
440 struct proc *p = sq->sq_proc;
441 ksiginfo_t *ksi;
442
443 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
444
445 if (p != NULL)
446 PROC_LOCK_ASSERT(p, MA_OWNED);
447
448 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
449 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
450 ksi->ksi_sigq = NULL;
451 if (ksiginfo_tryfree(ksi) && p != NULL)
452 p->p_pendingcnt--;
453 }
454
455 SIGEMPTYSET(sq->sq_signals);
456 SIGEMPTYSET(sq->sq_kill);
457 SIGEMPTYSET(sq->sq_ptrace);
458 }
459
460 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)461 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
462 {
463 sigset_t tmp;
464 struct proc *p1, *p2;
465 ksiginfo_t *ksi, *next;
466
467 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
468 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
469 p1 = src->sq_proc;
470 p2 = dst->sq_proc;
471 /* Move siginfo to target list */
472 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
473 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
474 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
475 if (p1 != NULL)
476 p1->p_pendingcnt--;
477 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
478 ksi->ksi_sigq = dst;
479 if (p2 != NULL)
480 p2->p_pendingcnt++;
481 }
482 }
483
484 /* Move pending bits to target list */
485 tmp = src->sq_kill;
486 SIGSETAND(tmp, *set);
487 SIGSETOR(dst->sq_kill, tmp);
488 SIGSETNAND(src->sq_kill, tmp);
489
490 tmp = src->sq_ptrace;
491 SIGSETAND(tmp, *set);
492 SIGSETOR(dst->sq_ptrace, tmp);
493 SIGSETNAND(src->sq_ptrace, tmp);
494
495 tmp = src->sq_signals;
496 SIGSETAND(tmp, *set);
497 SIGSETOR(dst->sq_signals, tmp);
498 SIGSETNAND(src->sq_signals, tmp);
499 }
500
501 #if 0
502 static void
503 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
504 {
505 sigset_t set;
506
507 SIGEMPTYSET(set);
508 SIGADDSET(set, signo);
509 sigqueue_move_set(src, dst, &set);
510 }
511 #endif
512
513 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)514 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
515 {
516 struct proc *p = sq->sq_proc;
517 ksiginfo_t *ksi, *next;
518
519 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
520
521 /* Remove siginfo queue */
522 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
523 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
524 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
525 ksi->ksi_sigq = NULL;
526 if (ksiginfo_tryfree(ksi) && p != NULL)
527 p->p_pendingcnt--;
528 }
529 }
530 SIGSETNAND(sq->sq_kill, *set);
531 SIGSETNAND(sq->sq_ptrace, *set);
532 SIGSETNAND(sq->sq_signals, *set);
533 }
534
535 void
sigqueue_delete(sigqueue_t * sq,int signo)536 sigqueue_delete(sigqueue_t *sq, int signo)
537 {
538 sigset_t set;
539
540 SIGEMPTYSET(set);
541 SIGADDSET(set, signo);
542 sigqueue_delete_set(sq, &set);
543 }
544
545 /* Remove a set of signals for a process */
546 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)547 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
548 {
549 sigqueue_t worklist;
550 struct thread *td0;
551
552 PROC_LOCK_ASSERT(p, MA_OWNED);
553
554 sigqueue_init(&worklist, NULL);
555 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
556
557 FOREACH_THREAD_IN_PROC(p, td0)
558 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
559
560 sigqueue_flush(&worklist);
561 }
562
563 void
sigqueue_delete_proc(struct proc * p,int signo)564 sigqueue_delete_proc(struct proc *p, int signo)
565 {
566 sigset_t set;
567
568 SIGEMPTYSET(set);
569 SIGADDSET(set, signo);
570 sigqueue_delete_set_proc(p, &set);
571 }
572
573 static void
sigqueue_delete_stopmask_proc(struct proc * p)574 sigqueue_delete_stopmask_proc(struct proc *p)
575 {
576 sigset_t set;
577
578 SIGEMPTYSET(set);
579 SIGADDSET(set, SIGSTOP);
580 SIGADDSET(set, SIGTSTP);
581 SIGADDSET(set, SIGTTIN);
582 SIGADDSET(set, SIGTTOU);
583 sigqueue_delete_set_proc(p, &set);
584 }
585
586 /*
587 * Determine signal that should be delivered to thread td, the current
588 * thread, 0 if none. If there is a pending stop signal with default
589 * action, the process stops in issignal().
590 */
591 int
cursig(struct thread * td)592 cursig(struct thread *td)
593 {
594 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
595 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
596 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
597 return (SIGPENDING(td) ? issignal(td) : 0);
598 }
599
600 /*
601 * Arrange for ast() to handle unmasked pending signals on return to user
602 * mode. This must be called whenever a signal is added to td_sigqueue or
603 * unmasked in td_sigmask.
604 */
605 void
signotify(struct thread * td)606 signotify(struct thread *td)
607 {
608 struct proc *p;
609
610 p = td->td_proc;
611
612 PROC_LOCK_ASSERT(p, MA_OWNED);
613
614 if (SIGPENDING(td)) {
615 thread_lock(td);
616 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
617 thread_unlock(td);
618 }
619 }
620
621 int
sigonstack(size_t sp)622 sigonstack(size_t sp)
623 {
624 struct thread *td = curthread;
625
626 return ((td->td_pflags & TDP_ALTSTACK) ?
627 #if defined(COMPAT_43)
628 ((td->td_sigstk.ss_size == 0) ?
629 (td->td_sigstk.ss_flags & SS_ONSTACK) :
630 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
631 #else
632 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
633 #endif
634 : 0);
635 }
636
637 static __inline int
sigprop(int sig)638 sigprop(int sig)
639 {
640
641 if (sig > 0 && sig < NSIG)
642 return (sigproptbl[_SIG_IDX(sig)]);
643 return (0);
644 }
645
646 int
sig_ffs(sigset_t * set)647 sig_ffs(sigset_t *set)
648 {
649 int i;
650
651 for (i = 0; i < _SIG_WORDS; i++)
652 if (set->__bits[i])
653 return (ffs(set->__bits[i]) + (i * 32));
654 return (0);
655 }
656
657 static bool
sigact_flag_test(struct sigaction * act,int flag)658 sigact_flag_test(struct sigaction *act, int flag)
659 {
660
661 /*
662 * SA_SIGINFO is reset when signal disposition is set to
663 * ignore or default. Other flags are kept according to user
664 * settings.
665 */
666 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
667 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
668 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
669 }
670
671 /*
672 * kern_sigaction
673 * sigaction
674 * freebsd4_sigaction
675 * osigaction
676 */
677 int
kern_sigaction(td,sig,act,oact,flags)678 kern_sigaction(td, sig, act, oact, flags)
679 struct thread *td;
680 register int sig;
681 struct sigaction *act, *oact;
682 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 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
700 oact->sa_flags = 0;
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) & SA_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(td,uap)833 sys_sigaction(td, uap)
834 struct thread *td;
835 register struct sigaction_args *uap;
836 {
837 struct sigaction act, oact;
838 register struct sigaction *actp, *oactp;
839 int error;
840
841 actp = (uap->act != NULL) ? &act : NULL;
842 oactp = (uap->oact != NULL) ? &oact : NULL;
843 if (actp) {
844 error = copyin(uap->act, actp, sizeof(act));
845 if (error)
846 return (error);
847 }
848 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
849 if (oactp && !error)
850 error = copyout(oactp, uap->oact, sizeof(oact));
851 return (error);
852 }
853
854 #ifdef COMPAT_FREEBSD4
855 #ifndef _SYS_SYSPROTO_H_
856 struct freebsd4_sigaction_args {
857 int sig;
858 struct sigaction *act;
859 struct sigaction *oact;
860 };
861 #endif
862 int
freebsd4_sigaction(td,uap)863 freebsd4_sigaction(td, uap)
864 struct thread *td;
865 register struct freebsd4_sigaction_args *uap;
866 {
867 struct sigaction act, oact;
868 register struct sigaction *actp, *oactp;
869 int error;
870
871
872 actp = (uap->act != NULL) ? &act : NULL;
873 oactp = (uap->oact != NULL) ? &oact : NULL;
874 if (actp) {
875 error = copyin(uap->act, actp, sizeof(act));
876 if (error)
877 return (error);
878 }
879 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
880 if (oactp && !error)
881 error = copyout(oactp, uap->oact, sizeof(oact));
882 return (error);
883 }
884 #endif /* COMAPT_FREEBSD4 */
885
886 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
887 #ifndef _SYS_SYSPROTO_H_
888 struct osigaction_args {
889 int signum;
890 struct osigaction *nsa;
891 struct osigaction *osa;
892 };
893 #endif
894 int
osigaction(td,uap)895 osigaction(td, uap)
896 struct thread *td;
897 register struct osigaction_args *uap;
898 {
899 struct osigaction sa;
900 struct sigaction nsa, osa;
901 register struct sigaction *nsap, *osap;
902 int error;
903
904 if (uap->signum <= 0 || uap->signum >= ONSIG)
905 return (EINVAL);
906
907 nsap = (uap->nsa != NULL) ? &nsa : NULL;
908 osap = (uap->osa != NULL) ? &osa : NULL;
909
910 if (nsap) {
911 error = copyin(uap->nsa, &sa, sizeof(sa));
912 if (error)
913 return (error);
914 nsap->sa_handler = sa.sa_handler;
915 nsap->sa_flags = sa.sa_flags;
916 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
917 }
918 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
919 if (osap && !error) {
920 sa.sa_handler = osap->sa_handler;
921 sa.sa_flags = osap->sa_flags;
922 SIG2OSIG(osap->sa_mask, sa.sa_mask);
923 error = copyout(&sa, uap->osa, sizeof(sa));
924 }
925 return (error);
926 }
927
928 #if !defined(__i386__)
929 /* Avoid replicating the same stub everywhere */
930 int
osigreturn(td,uap)931 osigreturn(td, uap)
932 struct thread *td;
933 struct osigreturn_args *uap;
934 {
935
936 return (nosys(td, (struct nosys_args *)uap));
937 }
938 #endif
939 #endif /* COMPAT_43 */
940
941 /*
942 * Initialize signal state for process 0;
943 * set to ignore signals that are ignored by default.
944 */
945 void
siginit(p)946 siginit(p)
947 struct proc *p;
948 {
949 register int i;
950 struct sigacts *ps;
951
952 PROC_LOCK(p);
953 ps = p->p_sigacts;
954 mtx_lock(&ps->ps_mtx);
955 for (i = 1; i <= NSIG; i++) {
956 if (sigprop(i) & SA_IGNORE && i != SIGCONT) {
957 SIGADDSET(ps->ps_sigignore, i);
958 }
959 }
960 mtx_unlock(&ps->ps_mtx);
961 PROC_UNLOCK(p);
962 }
963
964 /*
965 * Reset specified signal to the default disposition.
966 */
967 static void
sigdflt(struct sigacts * ps,int sig)968 sigdflt(struct sigacts *ps, int sig)
969 {
970
971 mtx_assert(&ps->ps_mtx, MA_OWNED);
972 SIGDELSET(ps->ps_sigcatch, sig);
973 if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT)
974 SIGADDSET(ps->ps_sigignore, sig);
975 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
976 SIGDELSET(ps->ps_siginfo, sig);
977 }
978
979 /*
980 * Reset signals for an exec of the specified process.
981 */
982 void
execsigs(struct proc * p)983 execsigs(struct proc *p)
984 {
985 struct sigacts *ps;
986 int sig;
987 struct thread *td;
988
989 /*
990 * Reset caught signals. Held signals remain held
991 * through td_sigmask (unless they were caught,
992 * and are now ignored by default).
993 */
994 PROC_LOCK_ASSERT(p, MA_OWNED);
995 ps = p->p_sigacts;
996 mtx_lock(&ps->ps_mtx);
997 while (SIGNOTEMPTY(ps->ps_sigcatch)) {
998 sig = sig_ffs(&ps->ps_sigcatch);
999 sigdflt(ps, sig);
1000 if ((sigprop(sig) & SA_IGNORE) != 0)
1001 sigqueue_delete_proc(p, sig);
1002 }
1003 /*
1004 * Reset stack state to the user stack.
1005 * Clear set of signals caught on the signal stack.
1006 */
1007 td = curthread;
1008 MPASS(td->td_proc == p);
1009 td->td_sigstk.ss_flags = SS_DISABLE;
1010 td->td_sigstk.ss_size = 0;
1011 td->td_sigstk.ss_sp = 0;
1012 td->td_pflags &= ~TDP_ALTSTACK;
1013 /*
1014 * Reset no zombies if child dies flag as Solaris does.
1015 */
1016 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1017 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1018 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1019 mtx_unlock(&ps->ps_mtx);
1020 }
1021
1022 /*
1023 * kern_sigprocmask()
1024 *
1025 * Manipulate signal mask.
1026 */
1027 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)1028 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1029 int flags)
1030 {
1031 sigset_t new_block, oset1;
1032 struct proc *p;
1033 int error;
1034
1035 p = td->td_proc;
1036 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1037 PROC_LOCK_ASSERT(p, MA_OWNED);
1038 else
1039 PROC_LOCK(p);
1040 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1041 ? MA_OWNED : MA_NOTOWNED);
1042 if (oset != NULL)
1043 *oset = td->td_sigmask;
1044
1045 error = 0;
1046 if (set != NULL) {
1047 switch (how) {
1048 case SIG_BLOCK:
1049 SIG_CANTMASK(*set);
1050 oset1 = td->td_sigmask;
1051 SIGSETOR(td->td_sigmask, *set);
1052 new_block = td->td_sigmask;
1053 SIGSETNAND(new_block, oset1);
1054 break;
1055 case SIG_UNBLOCK:
1056 SIGSETNAND(td->td_sigmask, *set);
1057 signotify(td);
1058 goto out;
1059 case SIG_SETMASK:
1060 SIG_CANTMASK(*set);
1061 oset1 = td->td_sigmask;
1062 if (flags & SIGPROCMASK_OLD)
1063 SIGSETLO(td->td_sigmask, *set);
1064 else
1065 td->td_sigmask = *set;
1066 new_block = td->td_sigmask;
1067 SIGSETNAND(new_block, oset1);
1068 signotify(td);
1069 break;
1070 default:
1071 error = EINVAL;
1072 goto out;
1073 }
1074
1075 /*
1076 * The new_block set contains signals that were not previously
1077 * blocked, but are blocked now.
1078 *
1079 * In case we block any signal that was not previously blocked
1080 * for td, and process has the signal pending, try to schedule
1081 * signal delivery to some thread that does not block the
1082 * signal, possibly waking it up.
1083 */
1084 if (p->p_numthreads != 1)
1085 reschedule_signals(p, new_block, flags);
1086 }
1087
1088 out:
1089 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1090 PROC_UNLOCK(p);
1091 return (error);
1092 }
1093
1094 #ifndef _SYS_SYSPROTO_H_
1095 struct sigprocmask_args {
1096 int how;
1097 const sigset_t *set;
1098 sigset_t *oset;
1099 };
1100 #endif
1101 int
sys_sigprocmask(td,uap)1102 sys_sigprocmask(td, uap)
1103 register struct thread *td;
1104 struct sigprocmask_args *uap;
1105 {
1106 sigset_t set, oset;
1107 sigset_t *setp, *osetp;
1108 int error;
1109
1110 setp = (uap->set != NULL) ? &set : NULL;
1111 osetp = (uap->oset != NULL) ? &oset : NULL;
1112 if (setp) {
1113 error = copyin(uap->set, setp, sizeof(set));
1114 if (error)
1115 return (error);
1116 }
1117 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1118 if (osetp && !error) {
1119 error = copyout(osetp, uap->oset, sizeof(oset));
1120 }
1121 return (error);
1122 }
1123
1124 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1125 #ifndef _SYS_SYSPROTO_H_
1126 struct osigprocmask_args {
1127 int how;
1128 osigset_t mask;
1129 };
1130 #endif
1131 int
osigprocmask(td,uap)1132 osigprocmask(td, uap)
1133 register struct thread *td;
1134 struct osigprocmask_args *uap;
1135 {
1136 sigset_t set, oset;
1137 int error;
1138
1139 OSIG2SIG(uap->mask, set);
1140 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1141 SIG2OSIG(oset, td->td_retval[0]);
1142 return (error);
1143 }
1144 #endif /* COMPAT_43 */
1145
1146 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1147 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1148 {
1149 ksiginfo_t ksi;
1150 sigset_t set;
1151 int error;
1152
1153 error = copyin(uap->set, &set, sizeof(set));
1154 if (error) {
1155 td->td_retval[0] = error;
1156 return (0);
1157 }
1158
1159 error = kern_sigtimedwait(td, set, &ksi, NULL);
1160 if (error) {
1161 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1162 error = ERESTART;
1163 if (error == ERESTART)
1164 return (error);
1165 td->td_retval[0] = error;
1166 return (0);
1167 }
1168
1169 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1170 td->td_retval[0] = error;
1171 return (0);
1172 }
1173
1174 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1175 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1176 {
1177 struct timespec ts;
1178 struct timespec *timeout;
1179 sigset_t set;
1180 ksiginfo_t ksi;
1181 int error;
1182
1183 if (uap->timeout) {
1184 error = copyin(uap->timeout, &ts, sizeof(ts));
1185 if (error)
1186 return (error);
1187
1188 timeout = &ts;
1189 } else
1190 timeout = NULL;
1191
1192 error = copyin(uap->set, &set, sizeof(set));
1193 if (error)
1194 return (error);
1195
1196 error = kern_sigtimedwait(td, set, &ksi, timeout);
1197 if (error)
1198 return (error);
1199
1200 if (uap->info)
1201 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1202
1203 if (error == 0)
1204 td->td_retval[0] = ksi.ksi_signo;
1205 return (error);
1206 }
1207
1208 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1209 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1210 {
1211 ksiginfo_t ksi;
1212 sigset_t set;
1213 int error;
1214
1215 error = copyin(uap->set, &set, sizeof(set));
1216 if (error)
1217 return (error);
1218
1219 error = kern_sigtimedwait(td, set, &ksi, NULL);
1220 if (error)
1221 return (error);
1222
1223 if (uap->info)
1224 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1225
1226 if (error == 0)
1227 td->td_retval[0] = ksi.ksi_signo;
1228 return (error);
1229 }
1230
1231 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1232 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1233 struct timespec *timeout)
1234 {
1235 struct sigacts *ps;
1236 sigset_t saved_mask, new_block;
1237 struct proc *p;
1238 int error, sig, timo, timevalid = 0;
1239 struct timespec rts, ets, ts;
1240 struct timeval tv;
1241
1242 p = td->td_proc;
1243 error = 0;
1244 ets.tv_sec = 0;
1245 ets.tv_nsec = 0;
1246
1247 if (timeout != NULL) {
1248 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1249 timevalid = 1;
1250 getnanouptime(&rts);
1251 ets = rts;
1252 timespecadd(&ets, timeout);
1253 }
1254 }
1255 ksiginfo_init(ksi);
1256 /* Some signals can not be waited for. */
1257 SIG_CANTMASK(waitset);
1258 ps = p->p_sigacts;
1259 PROC_LOCK(p);
1260 saved_mask = td->td_sigmask;
1261 SIGSETNAND(td->td_sigmask, waitset);
1262 for (;;) {
1263 mtx_lock(&ps->ps_mtx);
1264 sig = cursig(td);
1265 mtx_unlock(&ps->ps_mtx);
1266 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1267 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1268 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1269 error = 0;
1270 break;
1271 }
1272 }
1273
1274 if (error != 0)
1275 break;
1276
1277 /*
1278 * POSIX says this must be checked after looking for pending
1279 * signals.
1280 */
1281 if (timeout != NULL) {
1282 if (!timevalid) {
1283 error = EINVAL;
1284 break;
1285 }
1286 getnanouptime(&rts);
1287 if (timespeccmp(&rts, &ets, >=)) {
1288 error = EAGAIN;
1289 break;
1290 }
1291 ts = ets;
1292 timespecsub(&ts, &rts);
1293 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1294 timo = tvtohz(&tv);
1295 } else {
1296 timo = 0;
1297 }
1298
1299 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
1300
1301 if (timeout != NULL) {
1302 if (error == ERESTART) {
1303 /* Timeout can not be restarted. */
1304 error = EINTR;
1305 } else if (error == EAGAIN) {
1306 /* We will calculate timeout by ourself. */
1307 error = 0;
1308 }
1309 }
1310 }
1311
1312 new_block = saved_mask;
1313 SIGSETNAND(new_block, td->td_sigmask);
1314 td->td_sigmask = saved_mask;
1315 /*
1316 * Fewer signals can be delivered to us, reschedule signal
1317 * notification.
1318 */
1319 if (p->p_numthreads != 1)
1320 reschedule_signals(p, new_block, 0);
1321
1322 if (error == 0) {
1323 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1324
1325 if (ksi->ksi_code == SI_TIMER)
1326 itimer_accept(p, ksi->ksi_timerid, ksi);
1327
1328 #ifdef KTRACE
1329 if (KTRPOINT(td, KTR_PSIG)) {
1330 sig_t action;
1331
1332 mtx_lock(&ps->ps_mtx);
1333 action = ps->ps_sigact[_SIG_IDX(sig)];
1334 mtx_unlock(&ps->ps_mtx);
1335 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1336 }
1337 #endif
1338 if (sig == SIGKILL)
1339 sigexit(td, sig);
1340 }
1341 PROC_UNLOCK(p);
1342 return (error);
1343 }
1344
1345 #ifndef _SYS_SYSPROTO_H_
1346 struct sigpending_args {
1347 sigset_t *set;
1348 };
1349 #endif
1350 int
sys_sigpending(td,uap)1351 sys_sigpending(td, uap)
1352 struct thread *td;
1353 struct sigpending_args *uap;
1354 {
1355 struct proc *p = td->td_proc;
1356 sigset_t pending;
1357
1358 PROC_LOCK(p);
1359 pending = p->p_sigqueue.sq_signals;
1360 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1361 PROC_UNLOCK(p);
1362 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1363 }
1364
1365 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1366 #ifndef _SYS_SYSPROTO_H_
1367 struct osigpending_args {
1368 int dummy;
1369 };
1370 #endif
1371 int
osigpending(td,uap)1372 osigpending(td, uap)
1373 struct thread *td;
1374 struct osigpending_args *uap;
1375 {
1376 struct proc *p = td->td_proc;
1377 sigset_t pending;
1378
1379 PROC_LOCK(p);
1380 pending = p->p_sigqueue.sq_signals;
1381 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1382 PROC_UNLOCK(p);
1383 SIG2OSIG(pending, td->td_retval[0]);
1384 return (0);
1385 }
1386 #endif /* COMPAT_43 */
1387
1388 #if defined(COMPAT_43)
1389 /*
1390 * Generalized interface signal handler, 4.3-compatible.
1391 */
1392 #ifndef _SYS_SYSPROTO_H_
1393 struct osigvec_args {
1394 int signum;
1395 struct sigvec *nsv;
1396 struct sigvec *osv;
1397 };
1398 #endif
1399 /* ARGSUSED */
1400 int
osigvec(td,uap)1401 osigvec(td, uap)
1402 struct thread *td;
1403 register struct osigvec_args *uap;
1404 {
1405 struct sigvec vec;
1406 struct sigaction nsa, osa;
1407 register struct sigaction *nsap, *osap;
1408 int error;
1409
1410 if (uap->signum <= 0 || uap->signum >= ONSIG)
1411 return (EINVAL);
1412 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1413 osap = (uap->osv != NULL) ? &osa : NULL;
1414 if (nsap) {
1415 error = copyin(uap->nsv, &vec, sizeof(vec));
1416 if (error)
1417 return (error);
1418 nsap->sa_handler = vec.sv_handler;
1419 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1420 nsap->sa_flags = vec.sv_flags;
1421 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1422 }
1423 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1424 if (osap && !error) {
1425 vec.sv_handler = osap->sa_handler;
1426 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1427 vec.sv_flags = osap->sa_flags;
1428 vec.sv_flags &= ~SA_NOCLDWAIT;
1429 vec.sv_flags ^= SA_RESTART;
1430 error = copyout(&vec, uap->osv, sizeof(vec));
1431 }
1432 return (error);
1433 }
1434
1435 #ifndef _SYS_SYSPROTO_H_
1436 struct osigblock_args {
1437 int mask;
1438 };
1439 #endif
1440 int
osigblock(td,uap)1441 osigblock(td, uap)
1442 register struct thread *td;
1443 struct osigblock_args *uap;
1444 {
1445 sigset_t set, oset;
1446
1447 OSIG2SIG(uap->mask, set);
1448 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1449 SIG2OSIG(oset, td->td_retval[0]);
1450 return (0);
1451 }
1452
1453 #ifndef _SYS_SYSPROTO_H_
1454 struct osigsetmask_args {
1455 int mask;
1456 };
1457 #endif
1458 int
osigsetmask(td,uap)1459 osigsetmask(td, uap)
1460 struct thread *td;
1461 struct osigsetmask_args *uap;
1462 {
1463 sigset_t set, oset;
1464
1465 OSIG2SIG(uap->mask, set);
1466 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1467 SIG2OSIG(oset, td->td_retval[0]);
1468 return (0);
1469 }
1470 #endif /* COMPAT_43 */
1471
1472 /*
1473 * Suspend calling thread until signal, providing mask to be set in the
1474 * meantime.
1475 */
1476 #ifndef _SYS_SYSPROTO_H_
1477 struct sigsuspend_args {
1478 const sigset_t *sigmask;
1479 };
1480 #endif
1481 /* ARGSUSED */
1482 int
sys_sigsuspend(td,uap)1483 sys_sigsuspend(td, uap)
1484 struct thread *td;
1485 struct sigsuspend_args *uap;
1486 {
1487 sigset_t mask;
1488 int error;
1489
1490 error = copyin(uap->sigmask, &mask, sizeof(mask));
1491 if (error)
1492 return (error);
1493 return (kern_sigsuspend(td, mask));
1494 }
1495
1496 int
kern_sigsuspend(struct thread * td,sigset_t mask)1497 kern_sigsuspend(struct thread *td, sigset_t mask)
1498 {
1499 struct proc *p = td->td_proc;
1500 int has_sig, sig;
1501
1502 /*
1503 * When returning from sigsuspend, we want
1504 * the old mask to be restored after the
1505 * signal handler has finished. Thus, we
1506 * save it here and mark the sigacts structure
1507 * to indicate this.
1508 */
1509 PROC_LOCK(p);
1510 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1511 SIGPROCMASK_PROC_LOCKED);
1512 td->td_pflags |= TDP_OLDMASK;
1513
1514 /*
1515 * Process signals now. Otherwise, we can get spurious wakeup
1516 * due to signal entered process queue, but delivered to other
1517 * thread. But sigsuspend should return only on signal
1518 * delivery.
1519 */
1520 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1521 for (has_sig = 0; !has_sig;) {
1522 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1523 0) == 0)
1524 /* void */;
1525 thread_suspend_check(0);
1526 mtx_lock(&p->p_sigacts->ps_mtx);
1527 while ((sig = cursig(td)) != 0)
1528 has_sig += postsig(sig);
1529 mtx_unlock(&p->p_sigacts->ps_mtx);
1530 }
1531 PROC_UNLOCK(p);
1532 td->td_errno = EINTR;
1533 td->td_pflags |= TDP_NERRNO;
1534 return (EJUSTRETURN);
1535 }
1536
1537 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1538 /*
1539 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1540 * convention: libc stub passes mask, not pointer, to save a copyin.
1541 */
1542 #ifndef _SYS_SYSPROTO_H_
1543 struct osigsuspend_args {
1544 osigset_t mask;
1545 };
1546 #endif
1547 /* ARGSUSED */
1548 int
osigsuspend(td,uap)1549 osigsuspend(td, uap)
1550 struct thread *td;
1551 struct osigsuspend_args *uap;
1552 {
1553 sigset_t mask;
1554
1555 OSIG2SIG(uap->mask, mask);
1556 return (kern_sigsuspend(td, mask));
1557 }
1558 #endif /* COMPAT_43 */
1559
1560 #if defined(COMPAT_43)
1561 #ifndef _SYS_SYSPROTO_H_
1562 struct osigstack_args {
1563 struct sigstack *nss;
1564 struct sigstack *oss;
1565 };
1566 #endif
1567 /* ARGSUSED */
1568 int
osigstack(td,uap)1569 osigstack(td, uap)
1570 struct thread *td;
1571 register struct osigstack_args *uap;
1572 {
1573 struct sigstack nss, oss;
1574 int error = 0;
1575
1576 if (uap->nss != NULL) {
1577 error = copyin(uap->nss, &nss, sizeof(nss));
1578 if (error)
1579 return (error);
1580 }
1581 oss.ss_sp = td->td_sigstk.ss_sp;
1582 oss.ss_onstack = sigonstack(cpu_getstack(td));
1583 if (uap->nss != NULL) {
1584 td->td_sigstk.ss_sp = nss.ss_sp;
1585 td->td_sigstk.ss_size = 0;
1586 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1587 td->td_pflags |= TDP_ALTSTACK;
1588 }
1589 if (uap->oss != NULL)
1590 error = copyout(&oss, uap->oss, sizeof(oss));
1591
1592 return (error);
1593 }
1594 #endif /* COMPAT_43 */
1595
1596 #ifndef _SYS_SYSPROTO_H_
1597 struct sigaltstack_args {
1598 stack_t *ss;
1599 stack_t *oss;
1600 };
1601 #endif
1602 /* ARGSUSED */
1603 int
sys_sigaltstack(td,uap)1604 sys_sigaltstack(td, uap)
1605 struct thread *td;
1606 register struct sigaltstack_args *uap;
1607 {
1608 stack_t ss, oss;
1609 int error;
1610
1611 if (uap->ss != NULL) {
1612 error = copyin(uap->ss, &ss, sizeof(ss));
1613 if (error)
1614 return (error);
1615 }
1616 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1617 (uap->oss != NULL) ? &oss : NULL);
1618 if (error)
1619 return (error);
1620 if (uap->oss != NULL)
1621 error = copyout(&oss, uap->oss, sizeof(stack_t));
1622 return (error);
1623 }
1624
1625 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1626 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1627 {
1628 struct proc *p = td->td_proc;
1629 int oonstack;
1630
1631 oonstack = sigonstack(cpu_getstack(td));
1632
1633 if (oss != NULL) {
1634 *oss = td->td_sigstk;
1635 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1636 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1637 }
1638
1639 if (ss != NULL) {
1640 if (oonstack)
1641 return (EPERM);
1642 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1643 return (EINVAL);
1644 if (!(ss->ss_flags & SS_DISABLE)) {
1645 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1646 return (ENOMEM);
1647
1648 td->td_sigstk = *ss;
1649 td->td_pflags |= TDP_ALTSTACK;
1650 } else {
1651 td->td_pflags &= ~TDP_ALTSTACK;
1652 }
1653 }
1654 return (0);
1655 }
1656
1657 /*
1658 * Common code for kill process group/broadcast kill.
1659 * cp is calling process.
1660 */
1661 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1662 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1663 {
1664 struct proc *p;
1665 struct pgrp *pgrp;
1666 int err;
1667 int ret;
1668
1669 ret = ESRCH;
1670 if (all) {
1671 /*
1672 * broadcast
1673 */
1674 sx_slock(&allproc_lock);
1675 FOREACH_PROC_IN_SYSTEM(p) {
1676 PROC_LOCK(p);
1677 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1678 p == td->td_proc || p->p_state == PRS_NEW) {
1679 PROC_UNLOCK(p);
1680 continue;
1681 }
1682 err = p_cansignal(td, p, sig);
1683 if (err == 0) {
1684 if (sig)
1685 pksignal(p, sig, ksi);
1686 ret = err;
1687 }
1688 else if (ret == ESRCH)
1689 ret = err;
1690 PROC_UNLOCK(p);
1691 }
1692 sx_sunlock(&allproc_lock);
1693 } else {
1694 sx_slock(&proctree_lock);
1695 if (pgid == 0) {
1696 /*
1697 * zero pgid means send to my process group.
1698 */
1699 pgrp = td->td_proc->p_pgrp;
1700 PGRP_LOCK(pgrp);
1701 } else {
1702 pgrp = pgfind(pgid);
1703 if (pgrp == NULL) {
1704 sx_sunlock(&proctree_lock);
1705 return (ESRCH);
1706 }
1707 }
1708 sx_sunlock(&proctree_lock);
1709 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1710 PROC_LOCK(p);
1711 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1712 p->p_state == PRS_NEW) {
1713 PROC_UNLOCK(p);
1714 continue;
1715 }
1716 err = p_cansignal(td, p, sig);
1717 if (err == 0) {
1718 if (sig)
1719 pksignal(p, sig, ksi);
1720 ret = err;
1721 }
1722 else if (ret == ESRCH)
1723 ret = err;
1724 PROC_UNLOCK(p);
1725 }
1726 PGRP_UNLOCK(pgrp);
1727 }
1728 return (ret);
1729 }
1730
1731 #ifndef _SYS_SYSPROTO_H_
1732 struct kill_args {
1733 int pid;
1734 int signum;
1735 };
1736 #endif
1737 /* ARGSUSED */
1738 int
sys_kill(struct thread * td,struct kill_args * uap)1739 sys_kill(struct thread *td, struct kill_args *uap)
1740 {
1741 ksiginfo_t ksi;
1742 struct proc *p;
1743 int error;
1744
1745 /*
1746 * A process in capability mode can send signals only to himself.
1747 * The main rationale behind this is that abort(3) is implemented as
1748 * kill(getpid(), SIGABRT).
1749 */
1750 if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid)
1751 return (ECAPMODE);
1752
1753 AUDIT_ARG_SIGNUM(uap->signum);
1754 AUDIT_ARG_PID(uap->pid);
1755 if ((u_int)uap->signum > _SIG_MAXSIG)
1756 return (EINVAL);
1757
1758 ksiginfo_init(&ksi);
1759 ksi.ksi_signo = uap->signum;
1760 ksi.ksi_code = SI_USER;
1761 ksi.ksi_pid = td->td_proc->p_pid;
1762 ksi.ksi_uid = td->td_ucred->cr_ruid;
1763
1764 if (uap->pid > 0) {
1765 /* kill single process */
1766 if ((p = pfind(uap->pid)) == NULL) {
1767 if ((p = zpfind(uap->pid)) == NULL)
1768 return (ESRCH);
1769 }
1770 AUDIT_ARG_PROCESS(p);
1771 error = p_cansignal(td, p, uap->signum);
1772 if (error == 0 && uap->signum)
1773 pksignal(p, uap->signum, &ksi);
1774 PROC_UNLOCK(p);
1775 return (error);
1776 }
1777 switch (uap->pid) {
1778 case -1: /* broadcast signal */
1779 return (killpg1(td, uap->signum, 0, 1, &ksi));
1780 case 0: /* signal own process group */
1781 return (killpg1(td, uap->signum, 0, 0, &ksi));
1782 default: /* negative explicit process group */
1783 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
1784 }
1785 /* NOTREACHED */
1786 }
1787
1788 int
sys_pdkill(td,uap)1789 sys_pdkill(td, uap)
1790 struct thread *td;
1791 struct pdkill_args *uap;
1792 {
1793 #ifdef PROCDESC
1794 struct proc *p;
1795 cap_rights_t rights;
1796 int error;
1797
1798 AUDIT_ARG_SIGNUM(uap->signum);
1799 AUDIT_ARG_FD(uap->fd);
1800 if ((u_int)uap->signum > _SIG_MAXSIG)
1801 return (EINVAL);
1802
1803 error = procdesc_find(td, uap->fd,
1804 cap_rights_init(&rights, CAP_PDKILL), &p);
1805 if (error)
1806 return (error);
1807 AUDIT_ARG_PROCESS(p);
1808 error = p_cansignal(td, p, uap->signum);
1809 if (error == 0 && uap->signum)
1810 kern_psignal(p, uap->signum);
1811 PROC_UNLOCK(p);
1812 return (error);
1813 #else
1814 return (ENOSYS);
1815 #endif
1816 }
1817
1818 #if defined(COMPAT_43)
1819 #ifndef _SYS_SYSPROTO_H_
1820 struct okillpg_args {
1821 int pgid;
1822 int signum;
1823 };
1824 #endif
1825 /* ARGSUSED */
1826 int
okillpg(struct thread * td,struct okillpg_args * uap)1827 okillpg(struct thread *td, struct okillpg_args *uap)
1828 {
1829 ksiginfo_t ksi;
1830
1831 AUDIT_ARG_SIGNUM(uap->signum);
1832 AUDIT_ARG_PID(uap->pgid);
1833 if ((u_int)uap->signum > _SIG_MAXSIG)
1834 return (EINVAL);
1835
1836 ksiginfo_init(&ksi);
1837 ksi.ksi_signo = uap->signum;
1838 ksi.ksi_code = SI_USER;
1839 ksi.ksi_pid = td->td_proc->p_pid;
1840 ksi.ksi_uid = td->td_ucred->cr_ruid;
1841 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
1842 }
1843 #endif /* COMPAT_43 */
1844
1845 #ifndef _SYS_SYSPROTO_H_
1846 struct sigqueue_args {
1847 pid_t pid;
1848 int signum;
1849 /* union sigval */ void *value;
1850 };
1851 #endif
1852 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)1853 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
1854 {
1855 union sigval sv;
1856
1857 sv.sival_ptr = uap->value;
1858
1859 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
1860 }
1861
1862 int
kern_sigqueue(struct thread * td,pid_t pid,int signum,union sigval * value)1863 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
1864 {
1865 ksiginfo_t ksi;
1866 struct proc *p;
1867 int error;
1868
1869 if ((u_int)signum > _SIG_MAXSIG)
1870 return (EINVAL);
1871
1872 /*
1873 * Specification says sigqueue can only send signal to
1874 * single process.
1875 */
1876 if (pid <= 0)
1877 return (EINVAL);
1878
1879 if ((p = pfind(pid)) == NULL) {
1880 if ((p = zpfind(pid)) == NULL)
1881 return (ESRCH);
1882 }
1883 error = p_cansignal(td, p, signum);
1884 if (error == 0 && signum != 0) {
1885 ksiginfo_init(&ksi);
1886 ksi.ksi_flags = KSI_SIGQ;
1887 ksi.ksi_signo = signum;
1888 ksi.ksi_code = SI_QUEUE;
1889 ksi.ksi_pid = td->td_proc->p_pid;
1890 ksi.ksi_uid = td->td_ucred->cr_ruid;
1891 ksi.ksi_value = *value;
1892 error = pksignal(p, ksi.ksi_signo, &ksi);
1893 }
1894 PROC_UNLOCK(p);
1895 return (error);
1896 }
1897
1898 /*
1899 * Send a signal to a process group.
1900 */
1901 void
gsignal(int pgid,int sig,ksiginfo_t * ksi)1902 gsignal(int pgid, int sig, ksiginfo_t *ksi)
1903 {
1904 struct pgrp *pgrp;
1905
1906 if (pgid != 0) {
1907 sx_slock(&proctree_lock);
1908 pgrp = pgfind(pgid);
1909 sx_sunlock(&proctree_lock);
1910 if (pgrp != NULL) {
1911 pgsignal(pgrp, sig, 0, ksi);
1912 PGRP_UNLOCK(pgrp);
1913 }
1914 }
1915 }
1916
1917 /*
1918 * Send a signal to a process group. If checktty is 1,
1919 * limit to members which have a controlling terminal.
1920 */
1921 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)1922 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
1923 {
1924 struct proc *p;
1925
1926 if (pgrp) {
1927 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
1928 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1929 PROC_LOCK(p);
1930 if (p->p_state == PRS_NORMAL &&
1931 (checkctty == 0 || p->p_flag & P_CONTROLT))
1932 pksignal(p, sig, ksi);
1933 PROC_UNLOCK(p);
1934 }
1935 }
1936 }
1937
1938
1939 /*
1940 * Recalculate the signal mask and reset the signal disposition after
1941 * usermode frame for delivery is formed. Should be called after
1942 * mach-specific routine, because sysent->sv_sendsig() needs correct
1943 * ps_siginfo and signal mask.
1944 */
1945 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)1946 postsig_done(int sig, struct thread *td, struct sigacts *ps)
1947 {
1948 sigset_t mask;
1949
1950 mtx_assert(&ps->ps_mtx, MA_OWNED);
1951 td->td_ru.ru_nsignals++;
1952 mask = ps->ps_catchmask[_SIG_IDX(sig)];
1953 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1954 SIGADDSET(mask, sig);
1955 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
1956 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
1957 if (SIGISMEMBER(ps->ps_sigreset, sig))
1958 sigdflt(ps, sig);
1959 }
1960
1961
1962 /*
1963 * Send a signal caused by a trap to the current thread. If it will be
1964 * caught immediately, deliver it with correct code. Otherwise, post it
1965 * normally.
1966 */
1967 void
trapsignal(struct thread * td,ksiginfo_t * ksi)1968 trapsignal(struct thread *td, ksiginfo_t *ksi)
1969 {
1970 struct sigacts *ps;
1971 struct proc *p;
1972 int sig;
1973 int code;
1974
1975 p = td->td_proc;
1976 sig = ksi->ksi_signo;
1977 code = ksi->ksi_code;
1978 KASSERT(_SIG_VALID(sig), ("invalid signal"));
1979
1980 PROC_LOCK(p);
1981 ps = p->p_sigacts;
1982 mtx_lock(&ps->ps_mtx);
1983 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
1984 !SIGISMEMBER(td->td_sigmask, sig)) {
1985 #ifdef KTRACE
1986 if (KTRPOINT(curthread, KTR_PSIG))
1987 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
1988 &td->td_sigmask, code);
1989 #endif
1990 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
1991 ksi, &td->td_sigmask);
1992 postsig_done(sig, td, ps);
1993 mtx_unlock(&ps->ps_mtx);
1994 } else {
1995 /*
1996 * Avoid a possible infinite loop if the thread
1997 * masking the signal or process is ignoring the
1998 * signal.
1999 */
2000 if (kern_forcesigexit &&
2001 (SIGISMEMBER(td->td_sigmask, sig) ||
2002 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
2003 SIGDELSET(td->td_sigmask, sig);
2004 SIGDELSET(ps->ps_sigcatch, sig);
2005 SIGDELSET(ps->ps_sigignore, sig);
2006 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2007 }
2008 mtx_unlock(&ps->ps_mtx);
2009 p->p_code = code; /* XXX for core dump/debugger */
2010 p->p_sig = sig; /* XXX to verify code */
2011 tdsendsignal(p, td, sig, ksi);
2012 }
2013 PROC_UNLOCK(p);
2014 }
2015
2016 static struct thread *
sigtd(struct proc * p,int sig,int prop)2017 sigtd(struct proc *p, int sig, int prop)
2018 {
2019 struct thread *td, *signal_td;
2020
2021 PROC_LOCK_ASSERT(p, MA_OWNED);
2022
2023 /*
2024 * Check if current thread can handle the signal without
2025 * switching context to another thread.
2026 */
2027 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
2028 return (curthread);
2029 signal_td = NULL;
2030 FOREACH_THREAD_IN_PROC(p, td) {
2031 if (!SIGISMEMBER(td->td_sigmask, sig)) {
2032 signal_td = td;
2033 break;
2034 }
2035 }
2036 if (signal_td == NULL)
2037 signal_td = FIRST_THREAD_IN_PROC(p);
2038 return (signal_td);
2039 }
2040
2041 /*
2042 * Send the signal to the process. If the signal has an action, the action
2043 * is usually performed by the target process rather than the caller; we add
2044 * the signal to the set of pending signals for the process.
2045 *
2046 * Exceptions:
2047 * o When a stop signal is sent to a sleeping process that takes the
2048 * default action, the process is stopped without awakening it.
2049 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2050 * regardless of the signal action (eg, blocked or ignored).
2051 *
2052 * Other ignored signals are discarded immediately.
2053 *
2054 * NB: This function may be entered from the debugger via the "kill" DDB
2055 * command. There is little that can be done to mitigate the possibly messy
2056 * side effects of this unwise possibility.
2057 */
2058 void
kern_psignal(struct proc * p,int sig)2059 kern_psignal(struct proc *p, int sig)
2060 {
2061 ksiginfo_t ksi;
2062
2063 ksiginfo_init(&ksi);
2064 ksi.ksi_signo = sig;
2065 ksi.ksi_code = SI_KERNEL;
2066 (void) tdsendsignal(p, NULL, sig, &ksi);
2067 }
2068
2069 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)2070 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2071 {
2072
2073 return (tdsendsignal(p, NULL, sig, ksi));
2074 }
2075
2076 /* Utility function for finding a thread to send signal event to. */
2077 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)2078 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
2079 {
2080 struct thread *td;
2081
2082 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2083 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2084 if (td == NULL)
2085 return (ESRCH);
2086 *ttd = td;
2087 } else {
2088 *ttd = NULL;
2089 PROC_LOCK(p);
2090 }
2091 return (0);
2092 }
2093
2094 void
tdsignal(struct thread * td,int sig)2095 tdsignal(struct thread *td, int sig)
2096 {
2097 ksiginfo_t ksi;
2098
2099 ksiginfo_init(&ksi);
2100 ksi.ksi_signo = sig;
2101 ksi.ksi_code = SI_KERNEL;
2102 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2103 }
2104
2105 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2106 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2107 {
2108
2109 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2110 }
2111
2112 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2113 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2114 {
2115 sig_t action;
2116 sigqueue_t *sigqueue;
2117 int prop;
2118 struct sigacts *ps;
2119 int intrval;
2120 int ret = 0;
2121 int wakeup_swapper;
2122
2123 MPASS(td == NULL || p == td->td_proc);
2124 PROC_LOCK_ASSERT(p, MA_OWNED);
2125
2126 if (!_SIG_VALID(sig))
2127 panic("%s(): invalid signal %d", __func__, sig);
2128
2129 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2130
2131 /*
2132 * IEEE Std 1003.1-2001: return success when killing a zombie.
2133 */
2134 if (p->p_state == PRS_ZOMBIE) {
2135 if (ksi && (ksi->ksi_flags & KSI_INS))
2136 ksiginfo_tryfree(ksi);
2137 return (ret);
2138 }
2139
2140 ps = p->p_sigacts;
2141 KNOTE_LOCKED(&p->p_klist, NOTE_SIGNAL | sig);
2142 prop = sigprop(sig);
2143
2144 if (td == NULL) {
2145 td = sigtd(p, sig, prop);
2146 sigqueue = &p->p_sigqueue;
2147 } else
2148 sigqueue = &td->td_sigqueue;
2149
2150 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2151
2152 /*
2153 * If the signal is being ignored,
2154 * then we forget about it immediately.
2155 * (Note: we don't set SIGCONT in ps_sigignore,
2156 * and if it is set to SIG_IGN,
2157 * action will be SIG_DFL here.)
2158 */
2159 mtx_lock(&ps->ps_mtx);
2160 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2161 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2162
2163 mtx_unlock(&ps->ps_mtx);
2164 if (ksi && (ksi->ksi_flags & KSI_INS))
2165 ksiginfo_tryfree(ksi);
2166 return (ret);
2167 }
2168 if (SIGISMEMBER(td->td_sigmask, sig))
2169 action = SIG_HOLD;
2170 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2171 action = SIG_CATCH;
2172 else
2173 action = SIG_DFL;
2174 if (SIGISMEMBER(ps->ps_sigintr, sig))
2175 intrval = EINTR;
2176 else
2177 intrval = ERESTART;
2178 mtx_unlock(&ps->ps_mtx);
2179
2180 if (prop & SA_CONT)
2181 sigqueue_delete_stopmask_proc(p);
2182 else if (prop & SA_STOP) {
2183 /*
2184 * If sending a tty stop signal to a member of an orphaned
2185 * process group, discard the signal here if the action
2186 * is default; don't stop the process below if sleeping,
2187 * and don't clear any pending SIGCONT.
2188 */
2189 if ((prop & SA_TTYSTOP) &&
2190 (p->p_pgrp->pg_jobc == 0) &&
2191 (action == SIG_DFL)) {
2192 if (ksi && (ksi->ksi_flags & KSI_INS))
2193 ksiginfo_tryfree(ksi);
2194 return (ret);
2195 }
2196 sigqueue_delete_proc(p, SIGCONT);
2197 if (p->p_flag & P_CONTINUED) {
2198 p->p_flag &= ~P_CONTINUED;
2199 PROC_LOCK(p->p_pptr);
2200 sigqueue_take(p->p_ksi);
2201 PROC_UNLOCK(p->p_pptr);
2202 }
2203 }
2204
2205 ret = sigqueue_add(sigqueue, sig, ksi);
2206 if (ret != 0)
2207 return (ret);
2208 signotify(td);
2209 /*
2210 * Defer further processing for signals which are held,
2211 * except that stopped processes must be continued by SIGCONT.
2212 */
2213 if (action == SIG_HOLD &&
2214 !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
2215 return (ret);
2216
2217 /* SIGKILL: Remove procfs STOPEVENTs. */
2218 if (sig == SIGKILL) {
2219 /* from procfs_ioctl.c: PIOCBIC */
2220 p->p_stops = 0;
2221 /* from procfs_ioctl.c: PIOCCONT */
2222 p->p_step = 0;
2223 wakeup(&p->p_step);
2224 }
2225 /*
2226 * Some signals have a process-wide effect and a per-thread
2227 * component. Most processing occurs when the process next
2228 * tries to cross the user boundary, however there are some
2229 * times when processing needs to be done immediately, such as
2230 * waking up threads so that they can cross the user boundary.
2231 * We try to do the per-process part here.
2232 */
2233 if (P_SHOULDSTOP(p)) {
2234 KASSERT(!(p->p_flag & P_WEXIT),
2235 ("signal to stopped but exiting process"));
2236 if (sig == SIGKILL) {
2237 /*
2238 * If traced process is already stopped,
2239 * then no further action is necessary.
2240 */
2241 if (p->p_flag & P_TRACED)
2242 goto out;
2243 /*
2244 * SIGKILL sets process running.
2245 * It will die elsewhere.
2246 * All threads must be restarted.
2247 */
2248 p->p_flag &= ~P_STOPPED_SIG;
2249 goto runfast;
2250 }
2251
2252 if (prop & SA_CONT) {
2253 /*
2254 * If traced process is already stopped,
2255 * then no further action is necessary.
2256 */
2257 if (p->p_flag & P_TRACED)
2258 goto out;
2259 /*
2260 * If SIGCONT is default (or ignored), we continue the
2261 * process but don't leave the signal in sigqueue as
2262 * it has no further action. If SIGCONT is held, we
2263 * continue the process and leave the signal in
2264 * sigqueue. If the process catches SIGCONT, let it
2265 * handle the signal itself. If it isn't waiting on
2266 * an event, it goes back to run state.
2267 * Otherwise, process goes back to sleep state.
2268 */
2269 p->p_flag &= ~P_STOPPED_SIG;
2270 PROC_SLOCK(p);
2271 if (p->p_numthreads == p->p_suspcount) {
2272 PROC_SUNLOCK(p);
2273 p->p_flag |= P_CONTINUED;
2274 p->p_xstat = SIGCONT;
2275 PROC_LOCK(p->p_pptr);
2276 childproc_continued(p);
2277 PROC_UNLOCK(p->p_pptr);
2278 PROC_SLOCK(p);
2279 }
2280 if (action == SIG_DFL) {
2281 thread_unsuspend(p);
2282 PROC_SUNLOCK(p);
2283 sigqueue_delete(sigqueue, sig);
2284 goto out;
2285 }
2286 if (action == SIG_CATCH) {
2287 /*
2288 * The process wants to catch it so it needs
2289 * to run at least one thread, but which one?
2290 */
2291 PROC_SUNLOCK(p);
2292 goto runfast;
2293 }
2294 /*
2295 * The signal is not ignored or caught.
2296 */
2297 thread_unsuspend(p);
2298 PROC_SUNLOCK(p);
2299 goto out;
2300 }
2301
2302 if (prop & SA_STOP) {
2303 /*
2304 * If traced process is already stopped,
2305 * then no further action is necessary.
2306 */
2307 if (p->p_flag & P_TRACED)
2308 goto out;
2309 /*
2310 * Already stopped, don't need to stop again
2311 * (If we did the shell could get confused).
2312 * Just make sure the signal STOP bit set.
2313 */
2314 p->p_flag |= P_STOPPED_SIG;
2315 sigqueue_delete(sigqueue, sig);
2316 goto out;
2317 }
2318
2319 /*
2320 * All other kinds of signals:
2321 * If a thread is sleeping interruptibly, simulate a
2322 * wakeup so that when it is continued it will be made
2323 * runnable and can look at the signal. However, don't make
2324 * the PROCESS runnable, leave it stopped.
2325 * It may run a bit until it hits a thread_suspend_check().
2326 */
2327 wakeup_swapper = 0;
2328 PROC_SLOCK(p);
2329 thread_lock(td);
2330 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
2331 wakeup_swapper = sleepq_abort(td, intrval);
2332 thread_unlock(td);
2333 PROC_SUNLOCK(p);
2334 if (wakeup_swapper)
2335 kick_proc0();
2336 goto out;
2337 /*
2338 * Mutexes are short lived. Threads waiting on them will
2339 * hit thread_suspend_check() soon.
2340 */
2341 } else if (p->p_state == PRS_NORMAL) {
2342 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2343 tdsigwakeup(td, sig, action, intrval);
2344 goto out;
2345 }
2346
2347 MPASS(action == SIG_DFL);
2348
2349 if (prop & SA_STOP) {
2350 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2351 goto out;
2352 p->p_flag |= P_STOPPED_SIG;
2353 p->p_xstat = sig;
2354 PROC_SLOCK(p);
2355 sig_suspend_threads(td, p, 1);
2356 if (p->p_numthreads == p->p_suspcount) {
2357 /*
2358 * only thread sending signal to another
2359 * process can reach here, if thread is sending
2360 * signal to its process, because thread does
2361 * not suspend itself here, p_numthreads
2362 * should never be equal to p_suspcount.
2363 */
2364 thread_stopped(p);
2365 PROC_SUNLOCK(p);
2366 sigqueue_delete_proc(p, p->p_xstat);
2367 } else
2368 PROC_SUNLOCK(p);
2369 goto out;
2370 }
2371 } else {
2372 /* Not in "NORMAL" state. discard the signal. */
2373 sigqueue_delete(sigqueue, sig);
2374 goto out;
2375 }
2376
2377 /*
2378 * The process is not stopped so we need to apply the signal to all the
2379 * running threads.
2380 */
2381 runfast:
2382 tdsigwakeup(td, sig, action, intrval);
2383 PROC_SLOCK(p);
2384 thread_unsuspend(p);
2385 PROC_SUNLOCK(p);
2386 out:
2387 /* If we jump here, proc slock should not be owned. */
2388 PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
2389 return (ret);
2390 }
2391
2392 /*
2393 * The force of a signal has been directed against a single
2394 * thread. We need to see what we can do about knocking it
2395 * out of any sleep it may be in etc.
2396 */
2397 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2398 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2399 {
2400 struct proc *p = td->td_proc;
2401 register int prop;
2402 int wakeup_swapper;
2403
2404 wakeup_swapper = 0;
2405 PROC_LOCK_ASSERT(p, MA_OWNED);
2406 prop = sigprop(sig);
2407
2408 PROC_SLOCK(p);
2409 thread_lock(td);
2410 /*
2411 * Bring the priority of a thread up if we want it to get
2412 * killed in this lifetime. Be careful to avoid bumping the
2413 * priority of the idle thread, since we still allow to signal
2414 * kernel processes.
2415 */
2416 if (action == SIG_DFL && (prop & SA_KILL) != 0 &&
2417 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2418 sched_prio(td, PUSER);
2419 if (TD_ON_SLEEPQ(td)) {
2420 /*
2421 * If thread is sleeping uninterruptibly
2422 * we can't interrupt the sleep... the signal will
2423 * be noticed when the process returns through
2424 * trap() or syscall().
2425 */
2426 if ((td->td_flags & TDF_SINTR) == 0)
2427 goto out;
2428 /*
2429 * If SIGCONT is default (or ignored) and process is
2430 * asleep, we are finished; the process should not
2431 * be awakened.
2432 */
2433 if ((prop & SA_CONT) && action == SIG_DFL) {
2434 thread_unlock(td);
2435 PROC_SUNLOCK(p);
2436 sigqueue_delete(&p->p_sigqueue, sig);
2437 /*
2438 * It may be on either list in this state.
2439 * Remove from both for now.
2440 */
2441 sigqueue_delete(&td->td_sigqueue, sig);
2442 return;
2443 }
2444
2445 /*
2446 * Don't awaken a sleeping thread for SIGSTOP if the
2447 * STOP signal is deferred.
2448 */
2449 if ((prop & SA_STOP) && (td->td_flags & TDF_SBDRY))
2450 goto out;
2451
2452 /*
2453 * Give low priority threads a better chance to run.
2454 */
2455 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2456 sched_prio(td, PUSER);
2457
2458 wakeup_swapper = sleepq_abort(td, intrval);
2459 } else {
2460 /*
2461 * Other states do nothing with the signal immediately,
2462 * other than kicking ourselves if we are running.
2463 * It will either never be noticed, or noticed very soon.
2464 */
2465 #ifdef SMP
2466 if (TD_IS_RUNNING(td) && td != curthread)
2467 forward_signal(td);
2468 #endif
2469 }
2470 out:
2471 PROC_SUNLOCK(p);
2472 thread_unlock(td);
2473 if (wakeup_swapper)
2474 kick_proc0();
2475 }
2476
2477 static void
sig_suspend_threads(struct thread * td,struct proc * p,int sending)2478 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
2479 {
2480 struct thread *td2;
2481
2482 PROC_LOCK_ASSERT(p, MA_OWNED);
2483 PROC_SLOCK_ASSERT(p, MA_OWNED);
2484
2485 FOREACH_THREAD_IN_PROC(p, td2) {
2486 thread_lock(td2);
2487 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
2488 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
2489 (td2->td_flags & TDF_SINTR)) {
2490 if (td2->td_flags & TDF_SBDRY) {
2491 /*
2492 * Once a thread is asleep with
2493 * TDF_SBDRY set, it should never
2494 * become suspended due to this check.
2495 */
2496 KASSERT(!TD_IS_SUSPENDED(td2),
2497 ("thread with deferred stops suspended"));
2498 } else if (!TD_IS_SUSPENDED(td2)) {
2499 thread_suspend_one(td2);
2500 }
2501 } else if (!TD_IS_SUSPENDED(td2)) {
2502 if (sending || td != td2)
2503 td2->td_flags |= TDF_ASTPENDING;
2504 #ifdef SMP
2505 if (TD_IS_RUNNING(td2) && td2 != td)
2506 forward_signal(td2);
2507 #endif
2508 }
2509 thread_unlock(td2);
2510 }
2511 }
2512
2513 /*
2514 * Stop the process for an event deemed interesting to the debugger. If si is
2515 * non-NULL, this is a signal exchange; the new signal requested by the
2516 * debugger will be returned for handling. If si is NULL, this is some other
2517 * type of interesting event. The debugger may request a signal be delivered in
2518 * that case as well, however it will be deferred until it can be handled.
2519 */
2520 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2521 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2522 {
2523 struct proc *p = td->td_proc;
2524 struct thread *td2;
2525 ksiginfo_t ksi;
2526 int prop;
2527
2528 PROC_LOCK_ASSERT(p, MA_OWNED);
2529 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2530 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2531 &p->p_mtx.lock_object, "Stopping for traced signal");
2532
2533 td->td_xsig = sig;
2534
2535 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2536 td->td_dbgflags |= TDB_XSIG;
2537 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2538 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2539 PROC_SLOCK(p);
2540 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2541 if (P_KILLED(p)) {
2542 /*
2543 * Ensure that, if we've been PT_KILLed, the
2544 * exit status reflects that. Another thread
2545 * may also be in ptracestop(), having just
2546 * received the SIGKILL, but this thread was
2547 * unsuspended first.
2548 */
2549 td->td_dbgflags &= ~TDB_XSIG;
2550 td->td_xsig = SIGKILL;
2551 p->p_ptevents = 0;
2552 break;
2553 }
2554 if (p->p_flag & P_SINGLE_EXIT &&
2555 !(td->td_dbgflags & TDB_EXIT)) {
2556 /*
2557 * Ignore ptrace stops except for thread exit
2558 * events when the process exits.
2559 */
2560 td->td_dbgflags &= ~TDB_XSIG;
2561 PROC_SUNLOCK(p);
2562 return (0);
2563 }
2564
2565 /*
2566 * Make wait(2) work. Ensure that right after the
2567 * attach, the thread which was decided to become the
2568 * leader of attach gets reported to the waiter.
2569 * Otherwise, just avoid overwriting another thread's
2570 * assignment to p_xthread. If another thread has
2571 * already set p_xthread, the current thread will get
2572 * a chance to report itself upon the next iteration.
2573 */
2574 if ((td->td_dbgflags & TDB_FSTP) != 0 ||
2575 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
2576 p->p_xthread == NULL)) {
2577 p->p_xstat = sig;
2578 p->p_xthread = td;
2579 td->td_dbgflags &= ~TDB_FSTP;
2580 p->p_flag2 &= ~P2_PTRACE_FSTP;
2581 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2582 sig_suspend_threads(td, p, 0);
2583 }
2584 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2585 td->td_dbgflags &= ~TDB_STOPATFORK;
2586 cv_broadcast(&p->p_dbgwait);
2587 }
2588 stopme:
2589 thread_suspend_switch(td, p);
2590 if (p->p_xthread == td)
2591 p->p_xthread = NULL;
2592 if (!(p->p_flag & P_TRACED))
2593 break;
2594 if (td->td_dbgflags & TDB_SUSPEND) {
2595 if (p->p_flag & P_SINGLE_EXIT)
2596 break;
2597 goto stopme;
2598 }
2599 }
2600 PROC_SUNLOCK(p);
2601 }
2602
2603 if (si != NULL && sig == td->td_xsig) {
2604 /* Parent wants us to take the original signal unchanged. */
2605 si->ksi_flags |= KSI_HEAD;
2606 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2607 si->ksi_signo = 0;
2608 } else if (td->td_xsig != 0) {
2609 /*
2610 * If parent wants us to take a new signal, then it will leave
2611 * it in td->td_xsig; otherwise we just look for signals again.
2612 */
2613 ksiginfo_init(&ksi);
2614 ksi.ksi_signo = td->td_xsig;
2615 ksi.ksi_flags |= KSI_PTRACE;
2616 prop = sigprop(td->td_xsig);
2617 td2 = sigtd(p, td->td_xsig, prop);
2618 tdsendsignal(p, td2, td->td_xsig, &ksi);
2619 if (td != td2)
2620 return (0);
2621 }
2622
2623 return (td->td_xsig);
2624 }
2625
2626 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2627 reschedule_signals(struct proc *p, sigset_t block, int flags)
2628 {
2629 struct sigacts *ps;
2630 struct thread *td;
2631 int sig;
2632
2633 PROC_LOCK_ASSERT(p, MA_OWNED);
2634 ps = p->p_sigacts;
2635 mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ?
2636 MA_OWNED : MA_NOTOWNED);
2637 if (SIGISEMPTY(p->p_siglist))
2638 return;
2639 SIGSETAND(block, p->p_siglist);
2640 while ((sig = sig_ffs(&block)) != 0) {
2641 SIGDELSET(block, sig);
2642 td = sigtd(p, sig, 0);
2643 signotify(td);
2644 if (!(flags & SIGPROCMASK_PS_LOCKED))
2645 mtx_lock(&ps->ps_mtx);
2646 if (p->p_flag & P_TRACED ||
2647 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
2648 !SIGISMEMBER(td->td_sigmask, sig)))
2649 tdsigwakeup(td, sig, SIG_CATCH,
2650 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
2651 ERESTART));
2652 if (!(flags & SIGPROCMASK_PS_LOCKED))
2653 mtx_unlock(&ps->ps_mtx);
2654 }
2655 }
2656
2657 void
tdsigcleanup(struct thread * td)2658 tdsigcleanup(struct thread *td)
2659 {
2660 struct proc *p;
2661 sigset_t unblocked;
2662
2663 p = td->td_proc;
2664 PROC_LOCK_ASSERT(p, MA_OWNED);
2665
2666 sigqueue_flush(&td->td_sigqueue);
2667 if (p->p_numthreads == 1)
2668 return;
2669
2670 /*
2671 * Since we cannot handle signals, notify signal post code
2672 * about this by filling the sigmask.
2673 *
2674 * Also, if needed, wake up thread(s) that do not block the
2675 * same signals as the exiting thread, since the thread might
2676 * have been selected for delivery and woken up.
2677 */
2678 SIGFILLSET(unblocked);
2679 SIGSETNAND(unblocked, td->td_sigmask);
2680 SIGFILLSET(td->td_sigmask);
2681 reschedule_signals(p, unblocked, 0);
2682
2683 }
2684
2685 /*
2686 * Defer the delivery of SIGSTOP for the current thread. Returns true
2687 * if stops were deferred and false if they were already deferred.
2688 */
2689 int
sigdeferstop(void)2690 sigdeferstop(void)
2691 {
2692 struct thread *td;
2693
2694 td = curthread;
2695 if (td->td_flags & TDF_SBDRY)
2696 return (0);
2697 thread_lock(td);
2698 td->td_flags |= TDF_SBDRY;
2699 thread_unlock(td);
2700 return (1);
2701 }
2702
2703 /*
2704 * Permit the delivery of SIGSTOP for the current thread. This does
2705 * not immediately suspend if a stop was posted. Instead, the thread
2706 * will suspend either via ast() or a subsequent interruptible sleep.
2707 */
2708 int
sigallowstop(void)2709 sigallowstop(void)
2710 {
2711 struct thread *td;
2712 int prev;
2713
2714 td = curthread;
2715 thread_lock(td);
2716 prev = (td->td_flags & TDF_SBDRY) != 0;
2717 td->td_flags &= ~TDF_SBDRY;
2718 thread_unlock(td);
2719 return (prev);
2720 }
2721
2722 /*
2723 * If the current process has received a signal (should be caught or cause
2724 * termination, should interrupt current syscall), return the signal number.
2725 * Stop signals with default action are processed immediately, then cleared;
2726 * they aren't returned. This is checked after each entry to the system for
2727 * a syscall or trap (though this can usually be done without calling issignal
2728 * by checking the pending signal masks in cursig.) The normal call
2729 * sequence is
2730 *
2731 * while (sig = cursig(curthread))
2732 * postsig(sig);
2733 */
2734 static int
issignal(struct thread * td)2735 issignal(struct thread *td)
2736 {
2737 struct proc *p;
2738 struct sigacts *ps;
2739 struct sigqueue *queue;
2740 sigset_t sigpending;
2741 int sig, prop;
2742
2743 p = td->td_proc;
2744 ps = p->p_sigacts;
2745 mtx_assert(&ps->ps_mtx, MA_OWNED);
2746 PROC_LOCK_ASSERT(p, MA_OWNED);
2747 for (;;) {
2748 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
2749
2750 sigpending = td->td_sigqueue.sq_signals;
2751 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
2752 SIGSETNAND(sigpending, td->td_sigmask);
2753
2754 if (p->p_flag & P_PPWAIT || td->td_flags & TDF_SBDRY)
2755 SIG_STOPSIGMASK(sigpending);
2756 if (SIGISEMPTY(sigpending)) /* no signal to send */
2757 return (0);
2758 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
2759 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
2760 SIGISMEMBER(sigpending, SIGSTOP)) {
2761 /*
2762 * If debugger just attached, always consume
2763 * SIGSTOP from ptrace(PT_ATTACH) first, to
2764 * execute the debugger attach ritual in
2765 * order.
2766 */
2767 sig = SIGSTOP;
2768 td->td_dbgflags |= TDB_FSTP;
2769 } else {
2770 sig = sig_ffs(&sigpending);
2771 }
2772
2773 if (p->p_stops & S_SIG) {
2774 mtx_unlock(&ps->ps_mtx);
2775 stopevent(p, S_SIG, sig);
2776 mtx_lock(&ps->ps_mtx);
2777 }
2778
2779 /*
2780 * We should see pending but ignored signals
2781 * only if P_TRACED was on when they were posted.
2782 */
2783 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
2784 sigqueue_delete(&td->td_sigqueue, sig);
2785 sigqueue_delete(&p->p_sigqueue, sig);
2786 continue;
2787 }
2788 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
2789 /*
2790 * If traced, always stop.
2791 * Remove old signal from queue before the stop.
2792 * XXX shrug off debugger, it causes siginfo to
2793 * be thrown away.
2794 */
2795 queue = &td->td_sigqueue;
2796 td->td_dbgksi.ksi_signo = 0;
2797 if (sigqueue_get(queue, sig, &td->td_dbgksi) == 0) {
2798 queue = &p->p_sigqueue;
2799 sigqueue_get(queue, sig, &td->td_dbgksi);
2800 }
2801
2802 mtx_unlock(&ps->ps_mtx);
2803 sig = ptracestop(td, sig, &td->td_dbgksi);
2804 mtx_lock(&ps->ps_mtx);
2805
2806 td->td_dbgksi.ksi_signo = 0;
2807
2808 /*
2809 * Keep looking if the debugger discarded the signal
2810 * or replaced it with a masked signal.
2811 *
2812 * If the traced bit got turned off, go back up
2813 * to the top to rescan signals. This ensures
2814 * that p_sig* and p_sigact are consistent.
2815 */
2816 if (sig == 0 || (p->p_flag & P_TRACED) == 0)
2817 continue;
2818 }
2819
2820 prop = sigprop(sig);
2821
2822 /*
2823 * Decide whether the signal should be returned.
2824 * Return the signal's number, or fall through
2825 * to clear it from the pending mask.
2826 */
2827 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2828
2829 case (intptr_t)SIG_DFL:
2830 /*
2831 * Don't take default actions on system processes.
2832 */
2833 if (p->p_pid <= 1) {
2834 #ifdef DIAGNOSTIC
2835 /*
2836 * Are you sure you want to ignore SIGSEGV
2837 * in init? XXX
2838 */
2839 printf("Process (pid %lu) got signal %d\n",
2840 (u_long)p->p_pid, sig);
2841 #endif
2842 break; /* == ignore */
2843 }
2844 /*
2845 * If there is a pending stop signal to process with
2846 * default action, stop here, then clear the signal.
2847 * Traced or exiting processes should ignore stops.
2848 * Additionally, a member of an orphaned process group
2849 * should ignore tty stops.
2850 */
2851 if (prop & SA_STOP) {
2852 if (p->p_flag &
2853 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) ||
2854 (p->p_pgrp->pg_jobc == 0 &&
2855 prop & SA_TTYSTOP))
2856 break; /* == ignore */
2857 mtx_unlock(&ps->ps_mtx);
2858 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2859 &p->p_mtx.lock_object, "Catching SIGSTOP");
2860 sigqueue_delete(&td->td_sigqueue, sig);
2861 sigqueue_delete(&p->p_sigqueue, sig);
2862 p->p_flag |= P_STOPPED_SIG;
2863 p->p_xstat = sig;
2864 PROC_SLOCK(p);
2865 sig_suspend_threads(td, p, 0);
2866 thread_suspend_switch(td, p);
2867 PROC_SUNLOCK(p);
2868 mtx_lock(&ps->ps_mtx);
2869 goto next;
2870 } else if (prop & SA_IGNORE) {
2871 /*
2872 * Except for SIGCONT, shouldn't get here.
2873 * Default action is to ignore; drop it.
2874 */
2875 break; /* == ignore */
2876 } else
2877 return (sig);
2878 /*NOTREACHED*/
2879
2880 case (intptr_t)SIG_IGN:
2881 /*
2882 * Masking above should prevent us ever trying
2883 * to take action on an ignored signal other
2884 * than SIGCONT, unless process is traced.
2885 */
2886 if ((prop & SA_CONT) == 0 &&
2887 (p->p_flag & P_TRACED) == 0)
2888 printf("issignal\n");
2889 break; /* == ignore */
2890
2891 default:
2892 /*
2893 * This signal has an action, let
2894 * postsig() process it.
2895 */
2896 return (sig);
2897 }
2898 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
2899 sigqueue_delete(&p->p_sigqueue, sig);
2900 next:;
2901 }
2902 /* NOTREACHED */
2903 }
2904
2905 void
thread_stopped(struct proc * p)2906 thread_stopped(struct proc *p)
2907 {
2908 int n;
2909
2910 PROC_LOCK_ASSERT(p, MA_OWNED);
2911 PROC_SLOCK_ASSERT(p, MA_OWNED);
2912 n = p->p_suspcount;
2913 if (p == curproc)
2914 n++;
2915 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
2916 PROC_SUNLOCK(p);
2917 p->p_flag &= ~P_WAITED;
2918 PROC_LOCK(p->p_pptr);
2919 childproc_stopped(p, (p->p_flag & P_TRACED) ?
2920 CLD_TRAPPED : CLD_STOPPED);
2921 PROC_UNLOCK(p->p_pptr);
2922 PROC_SLOCK(p);
2923 }
2924 }
2925
2926 /*
2927 * Take the action for the specified signal
2928 * from the current set of pending signals.
2929 */
2930 int
postsig(sig)2931 postsig(sig)
2932 register int sig;
2933 {
2934 struct thread *td = curthread;
2935 register struct proc *p = td->td_proc;
2936 struct sigacts *ps;
2937 sig_t action;
2938 ksiginfo_t ksi;
2939 sigset_t returnmask;
2940
2941 KASSERT(sig != 0, ("postsig"));
2942
2943 PROC_LOCK_ASSERT(p, MA_OWNED);
2944 ps = p->p_sigacts;
2945 mtx_assert(&ps->ps_mtx, MA_OWNED);
2946 ksiginfo_init(&ksi);
2947 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
2948 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
2949 return (0);
2950 ksi.ksi_signo = sig;
2951 if (ksi.ksi_code == SI_TIMER)
2952 itimer_accept(p, ksi.ksi_timerid, &ksi);
2953 action = ps->ps_sigact[_SIG_IDX(sig)];
2954 #ifdef KTRACE
2955 if (KTRPOINT(td, KTR_PSIG))
2956 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
2957 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
2958 #endif
2959 if (p->p_stops & S_SIG) {
2960 mtx_unlock(&ps->ps_mtx);
2961 stopevent(p, S_SIG, sig);
2962 mtx_lock(&ps->ps_mtx);
2963 }
2964
2965 if (action == SIG_DFL) {
2966 /*
2967 * Default action, where the default is to kill
2968 * the process. (Other cases were ignored above.)
2969 */
2970 mtx_unlock(&ps->ps_mtx);
2971 sigexit(td, sig);
2972 /* NOTREACHED */
2973 } else {
2974 /*
2975 * If we get here, the signal must be caught.
2976 */
2977 KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
2978 ("postsig action"));
2979 /*
2980 * Set the new mask value and also defer further
2981 * occurrences of this signal.
2982 *
2983 * Special case: user has done a sigsuspend. Here the
2984 * current mask is not of interest, but rather the
2985 * mask from before the sigsuspend is what we want
2986 * restored after the signal processing is completed.
2987 */
2988 if (td->td_pflags & TDP_OLDMASK) {
2989 returnmask = td->td_oldsigmask;
2990 td->td_pflags &= ~TDP_OLDMASK;
2991 } else
2992 returnmask = td->td_sigmask;
2993
2994 if (p->p_sig == sig) {
2995 p->p_code = 0;
2996 p->p_sig = 0;
2997 }
2998 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
2999 postsig_done(sig, td, ps);
3000 }
3001 return (1);
3002 }
3003
3004 /*
3005 * Kill the current process for stated reason.
3006 */
3007 void
killproc(p,why)3008 killproc(p, why)
3009 struct proc *p;
3010 char *why;
3011 {
3012
3013 PROC_LOCK_ASSERT(p, MA_OWNED);
3014 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3015 p->p_comm);
3016 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid,
3017 p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why);
3018 p->p_flag |= P_WKILLED;
3019 kern_psignal(p, SIGKILL);
3020 }
3021
3022 /*
3023 * Force the current process to exit with the specified signal, dumping core
3024 * if appropriate. We bypass the normal tests for masked and caught signals,
3025 * allowing unrecoverable failures to terminate the process without changing
3026 * signal state. Mark the accounting record with the signal termination.
3027 * If dumping core, save the signal number for the debugger. Calls exit and
3028 * does not return.
3029 */
3030 void
sigexit(td,sig)3031 sigexit(td, sig)
3032 struct thread *td;
3033 int sig;
3034 {
3035 struct proc *p = td->td_proc;
3036
3037 PROC_LOCK_ASSERT(p, MA_OWNED);
3038 p->p_acflag |= AXSIG;
3039 /*
3040 * We must be single-threading to generate a core dump. This
3041 * ensures that the registers in the core file are up-to-date.
3042 * Also, the ELF dump handler assumes that the thread list doesn't
3043 * change out from under it.
3044 *
3045 * XXX If another thread attempts to single-thread before us
3046 * (e.g. via fork()), we won't get a dump at all.
3047 */
3048 if ((sigprop(sig) & SA_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) {
3049 p->p_sig = sig;
3050 /*
3051 * Log signals which would cause core dumps
3052 * (Log as LOG_INFO to appease those who don't want
3053 * these messages.)
3054 * XXX : Todo, as well as euid, write out ruid too
3055 * Note that coredump() drops proc lock.
3056 */
3057 if (coredump(td) == 0)
3058 sig |= WCOREFLAG;
3059 if (kern_logsigexit)
3060 log(LOG_INFO,
3061 "pid %d (%s), uid %d: exited on signal %d%s\n",
3062 p->p_pid, p->p_comm,
3063 td->td_ucred ? td->td_ucred->cr_uid : -1,
3064 sig &~ WCOREFLAG,
3065 sig & WCOREFLAG ? " (core dumped)" : "");
3066 } else
3067 PROC_UNLOCK(p);
3068 exit1(td, W_EXITCODE(0, sig));
3069 /* NOTREACHED */
3070 }
3071
3072 /*
3073 * Send queued SIGCHLD to parent when child process's state
3074 * is changed.
3075 */
3076 static void
sigparent(struct proc * p,int reason,int status)3077 sigparent(struct proc *p, int reason, int status)
3078 {
3079 PROC_LOCK_ASSERT(p, MA_OWNED);
3080 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3081
3082 if (p->p_ksi != NULL) {
3083 p->p_ksi->ksi_signo = SIGCHLD;
3084 p->p_ksi->ksi_code = reason;
3085 p->p_ksi->ksi_status = status;
3086 p->p_ksi->ksi_pid = p->p_pid;
3087 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3088 if (KSI_ONQ(p->p_ksi))
3089 return;
3090 }
3091 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3092 }
3093
3094 static void
childproc_jobstate(struct proc * p,int reason,int sig)3095 childproc_jobstate(struct proc *p, int reason, int sig)
3096 {
3097 struct sigacts *ps;
3098
3099 PROC_LOCK_ASSERT(p, MA_OWNED);
3100 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3101
3102 /*
3103 * Wake up parent sleeping in kern_wait(), also send
3104 * SIGCHLD to parent, but SIGCHLD does not guarantee
3105 * that parent will awake, because parent may masked
3106 * the signal.
3107 */
3108 p->p_pptr->p_flag |= P_STATCHILD;
3109 wakeup(p->p_pptr);
3110
3111 ps = p->p_pptr->p_sigacts;
3112 mtx_lock(&ps->ps_mtx);
3113 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3114 mtx_unlock(&ps->ps_mtx);
3115 sigparent(p, reason, sig);
3116 } else
3117 mtx_unlock(&ps->ps_mtx);
3118 }
3119
3120 void
childproc_stopped(struct proc * p,int reason)3121 childproc_stopped(struct proc *p, int reason)
3122 {
3123 /* p_xstat is a plain signal number, not a full wait() status here. */
3124 childproc_jobstate(p, reason, p->p_xstat);
3125 }
3126
3127 void
childproc_continued(struct proc * p)3128 childproc_continued(struct proc *p)
3129 {
3130 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3131 }
3132
3133 void
childproc_exited(struct proc * p)3134 childproc_exited(struct proc *p)
3135 {
3136 int reason;
3137 int xstat = p->p_xstat; /* convert to int */
3138 int status;
3139
3140 if (WCOREDUMP(xstat))
3141 reason = CLD_DUMPED, status = WTERMSIG(xstat);
3142 else if (WIFSIGNALED(xstat))
3143 reason = CLD_KILLED, status = WTERMSIG(xstat);
3144 else
3145 reason = CLD_EXITED, status = WEXITSTATUS(xstat);
3146 /*
3147 * XXX avoid calling wakeup(p->p_pptr), the work is
3148 * done in exit1().
3149 */
3150 sigparent(p, reason, status);
3151 }
3152
3153 /*
3154 * We only have 1 character for the core count in the format
3155 * string, so the range will be 0-9
3156 */
3157 #define MAX_NUM_CORES 10
3158 static int num_cores = 5;
3159
3160 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3161 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3162 {
3163 int error;
3164 int new_val;
3165
3166 new_val = num_cores;
3167 error = sysctl_handle_int(oidp, &new_val, 0, req);
3168 if (error != 0 || req->newptr == NULL)
3169 return (error);
3170 if (new_val > MAX_NUM_CORES)
3171 new_val = MAX_NUM_CORES;
3172 if (new_val < 0)
3173 new_val = 0;
3174 num_cores = new_val;
3175 return (0);
3176 }
3177 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
3178 0, sizeof(int), sysctl_debug_num_cores_check, "I", "");
3179
3180 #if defined(COMPRESS_USER_CORES)
3181 int compress_user_cores = 1;
3182 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RW,
3183 &compress_user_cores, 0, "Compression of user corefiles");
3184
3185 int compress_user_cores_gzlevel = -1; /* default level */
3186 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RW,
3187 &compress_user_cores_gzlevel, -1, "Corefile gzip compression level");
3188
3189 #define GZ_SUFFIX ".gz"
3190 #define GZ_SUFFIX_LEN 3
3191 #endif
3192
3193 static char corefilename[MAXPATHLEN] = {"%N.core"};
3194 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3195 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
3196 sizeof(corefilename), "Process corefile name format string");
3197
3198 /*
3199 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3200 * Expand the name described in corefilename, using name, uid, and pid
3201 * and open/create core file.
3202 * corefilename is a printf-like string, with three format specifiers:
3203 * %N name of process ("name")
3204 * %P process id (pid)
3205 * %U user id (uid)
3206 * For example, "%N.core" is the default; they can be disabled completely
3207 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3208 * This is controlled by the sysctl variable kern.corefile (see above).
3209 */
3210 static int
corefile_open(const char * comm,uid_t uid,pid_t pid,struct thread * td,int compress,struct vnode ** vpp,char ** namep)3211 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
3212 int compress, struct vnode **vpp, char **namep)
3213 {
3214 struct nameidata nd;
3215 struct sbuf sb;
3216 const char *format;
3217 char *hostname, *name;
3218 int indexpos, i, error, cmode, flags, oflags;
3219
3220 hostname = NULL;
3221 format = corefilename;
3222 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
3223 indexpos = -1;
3224 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
3225 for (i = 0; format[i] != '\0'; i++) {
3226 switch (format[i]) {
3227 case '%': /* Format character */
3228 i++;
3229 switch (format[i]) {
3230 case '%':
3231 sbuf_putc(&sb, '%');
3232 break;
3233 case 'H': /* hostname */
3234 if (hostname == NULL) {
3235 hostname = malloc(MAXHOSTNAMELEN,
3236 M_TEMP, M_WAITOK);
3237 }
3238 getcredhostname(td->td_ucred, hostname,
3239 MAXHOSTNAMELEN);
3240 sbuf_printf(&sb, "%s", hostname);
3241 break;
3242 case 'I': /* autoincrementing index */
3243 sbuf_printf(&sb, "0");
3244 indexpos = sbuf_len(&sb) - 1;
3245 break;
3246 case 'N': /* process name */
3247 sbuf_printf(&sb, "%s", comm);
3248 break;
3249 case 'P': /* process id */
3250 sbuf_printf(&sb, "%u", pid);
3251 break;
3252 case 'U': /* user id */
3253 sbuf_printf(&sb, "%u", uid);
3254 break;
3255 default:
3256 log(LOG_ERR,
3257 "Unknown format character %c in "
3258 "corename `%s'\n", format[i], format);
3259 break;
3260 }
3261 break;
3262 default:
3263 sbuf_putc(&sb, format[i]);
3264 break;
3265 }
3266 }
3267 free(hostname, M_TEMP);
3268 #ifdef COMPRESS_USER_CORES
3269 if (compress)
3270 sbuf_printf(&sb, GZ_SUFFIX);
3271 #endif
3272 if (sbuf_error(&sb) != 0) {
3273 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
3274 "long\n", (long)pid, comm, (u_long)uid);
3275 sbuf_delete(&sb);
3276 free(name, M_TEMP);
3277 return (ENOMEM);
3278 }
3279 sbuf_finish(&sb);
3280 sbuf_delete(&sb);
3281
3282 cmode = S_IRUSR | S_IWUSR;
3283 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3284 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3285
3286 /*
3287 * If the core format has a %I in it, then we need to check
3288 * for existing corefiles before returning a name.
3289 * To do this we iterate over 0..num_cores to find a
3290 * non-existing core file name to use.
3291 */
3292 if (indexpos != -1) {
3293 for (i = 0; i < num_cores; i++) {
3294 flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW;
3295 name[indexpos] = '0' + i;
3296 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3297 error = vn_open_cred(&nd, &flags, cmode, oflags,
3298 td->td_ucred, NULL);
3299 if (error) {
3300 if (error == EEXIST)
3301 continue;
3302 log(LOG_ERR,
3303 "pid %d (%s), uid (%u): Path `%s' failed "
3304 "on initial open test, error = %d\n",
3305 pid, comm, uid, name, error);
3306 }
3307 goto out;
3308 }
3309 }
3310
3311 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3312 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
3313 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL);
3314 out:
3315 if (error) {
3316 #ifdef AUDIT
3317 audit_proc_coredump(td, name, error);
3318 #endif
3319 free(name, M_TEMP);
3320 return (error);
3321 }
3322 NDFREE(&nd, NDF_ONLY_PNBUF);
3323 *vpp = nd.ni_vp;
3324 *namep = name;
3325 return (0);
3326 }
3327
3328 static int
coredump_sanitise_path(const char * path)3329 coredump_sanitise_path(const char *path)
3330 {
3331 size_t i;
3332
3333 /*
3334 * Only send a subset of ASCII to devd(8) because it
3335 * might pass these strings to sh -c.
3336 */
3337 for (i = 0; path[i]; i++)
3338 if (!(isalpha(path[i]) || isdigit(path[i])) &&
3339 path[i] != '/' && path[i] != '.' &&
3340 path[i] != '-')
3341 return (0);
3342
3343 return (1);
3344 }
3345
3346 /*
3347 * Dump a process' core. The main routine does some
3348 * policy checking, and creates the name of the coredump;
3349 * then it passes on a vnode and a size limit to the process-specific
3350 * coredump routine if there is one; if there _is not_ one, it returns
3351 * ENOSYS; otherwise it returns the error from the process-specific routine.
3352 */
3353
3354 static int
coredump(struct thread * td)3355 coredump(struct thread *td)
3356 {
3357 struct proc *p = td->td_proc;
3358 struct ucred *cred = td->td_ucred;
3359 struct vnode *vp;
3360 struct flock lf;
3361 struct vattr vattr;
3362 int error, error1, locked;
3363 struct mount *mp;
3364 char *name; /* name of corefile */
3365 off_t limit;
3366 int compress;
3367 char *data = NULL;
3368 char *fullpath, *freepath = NULL;
3369 size_t len;
3370 static const char comm_name[] = "comm=";
3371 static const char core_name[] = "core=";
3372
3373 #ifdef COMPRESS_USER_CORES
3374 compress = compress_user_cores;
3375 #else
3376 compress = 0;
3377 #endif
3378 PROC_LOCK_ASSERT(p, MA_OWNED);
3379 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
3380 _STOPEVENT(p, S_CORE, 0);
3381
3382 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
3383 (p->p_flag2 & P2_NOTRACE) != 0) {
3384 PROC_UNLOCK(p);
3385 return (EFAULT);
3386 }
3387
3388 /*
3389 * Note that the bulk of limit checking is done after
3390 * the corefile is created. The exception is if the limit
3391 * for corefiles is 0, in which case we don't bother
3392 * creating the corefile at all. This layout means that
3393 * a corefile is truncated instead of not being created,
3394 * if it is larger than the limit.
3395 */
3396 limit = (off_t)lim_cur(p, RLIMIT_CORE);
3397 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
3398 PROC_UNLOCK(p);
3399 return (EFBIG);
3400 }
3401 PROC_UNLOCK(p);
3402
3403 restart:
3404 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, compress,
3405 &vp, &name);
3406 if (error != 0)
3407 return (error);
3408
3409 /* Don't dump to non-regular files or files with links. */
3410 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
3411 vattr.va_nlink != 1) {
3412 VOP_UNLOCK(vp, 0);
3413 error = EFAULT;
3414 goto out;
3415 }
3416
3417 VOP_UNLOCK(vp, 0);
3418 lf.l_whence = SEEK_SET;
3419 lf.l_start = 0;
3420 lf.l_len = 0;
3421 lf.l_type = F_WRLCK;
3422 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
3423
3424 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
3425 lf.l_type = F_UNLCK;
3426 if (locked)
3427 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3428 if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
3429 goto out;
3430 if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
3431 goto out;
3432 free(name, M_TEMP);
3433 goto restart;
3434 }
3435
3436 VATTR_NULL(&vattr);
3437 vattr.va_size = 0;
3438 if (set_core_nodump_flag)
3439 vattr.va_flags = UF_NODUMP;
3440 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3441 VOP_SETATTR(vp, &vattr, cred);
3442 VOP_UNLOCK(vp, 0);
3443 vn_finished_write(mp);
3444 PROC_LOCK(p);
3445 p->p_acflag |= ACORE;
3446 PROC_UNLOCK(p);
3447
3448 if (p->p_sysent->sv_coredump != NULL) {
3449 error = p->p_sysent->sv_coredump(td, vp, limit,
3450 compress ? IMGACT_CORE_COMPRESS : 0);
3451 } else {
3452 error = ENOSYS;
3453 }
3454
3455 if (locked) {
3456 lf.l_type = F_UNLCK;
3457 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3458 }
3459
3460 /*
3461 * Notify the userland helper that a process triggered a core dump.
3462 * This allows the helper to run an automated debugging session.
3463 */
3464 if (error != 0 || coredump_devctl == 0)
3465 goto out;
3466 len = MAXPATHLEN * 2 + sizeof(comm_name) - 1 +
3467 sizeof(' ') + sizeof(core_name) - 1;
3468 data = malloc(len, M_TEMP, M_WAITOK);
3469 if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
3470 goto out;
3471 if (!coredump_sanitise_path(fullpath))
3472 goto out;
3473 snprintf(data, len, "%s%s ", comm_name, fullpath);
3474 free(freepath, M_TEMP);
3475 freepath = NULL;
3476 if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
3477 goto out;
3478 if (!coredump_sanitise_path(fullpath))
3479 goto out;
3480 strlcat(data, core_name, len);
3481 strlcat(data, fullpath, len);
3482 devctl_notify("kernel", "signal", "coredump", data);
3483 out:
3484 error1 = vn_close(vp, FWRITE, cred, td);
3485 if (error == 0)
3486 error = error1;
3487 #ifdef AUDIT
3488 audit_proc_coredump(td, name, error);
3489 #endif
3490 free(freepath, M_TEMP);
3491 free(data, M_TEMP);
3492 free(name, M_TEMP);
3493 return (error);
3494 }
3495
3496 /*
3497 * Nonexistent system call-- signal process (may want to handle it). Flag
3498 * error in case process won't see signal immediately (blocked or ignored).
3499 */
3500 #ifndef _SYS_SYSPROTO_H_
3501 struct nosys_args {
3502 int dummy;
3503 };
3504 #endif
3505 /* ARGSUSED */
3506 int
nosys(td,args)3507 nosys(td, args)
3508 struct thread *td;
3509 struct nosys_args *args;
3510 {
3511 struct proc *p = td->td_proc;
3512
3513 PROC_LOCK(p);
3514 tdsignal(td, SIGSYS);
3515 PROC_UNLOCK(p);
3516 return (ENOSYS);
3517 }
3518
3519 /*
3520 * Send a SIGIO or SIGURG signal to a process or process group using stored
3521 * credentials rather than those of the current process.
3522 */
3523 void
pgsigio(sigiop,sig,checkctty)3524 pgsigio(sigiop, sig, checkctty)
3525 struct sigio **sigiop;
3526 int sig, checkctty;
3527 {
3528 ksiginfo_t ksi;
3529 struct sigio *sigio;
3530
3531 ksiginfo_init(&ksi);
3532 ksi.ksi_signo = sig;
3533 ksi.ksi_code = SI_KERNEL;
3534
3535 SIGIO_LOCK();
3536 sigio = *sigiop;
3537 if (sigio == NULL) {
3538 SIGIO_UNLOCK();
3539 return;
3540 }
3541 if (sigio->sio_pgid > 0) {
3542 PROC_LOCK(sigio->sio_proc);
3543 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3544 kern_psignal(sigio->sio_proc, sig);
3545 PROC_UNLOCK(sigio->sio_proc);
3546 } else if (sigio->sio_pgid < 0) {
3547 struct proc *p;
3548
3549 PGRP_LOCK(sigio->sio_pgrp);
3550 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3551 PROC_LOCK(p);
3552 if (p->p_state == PRS_NORMAL &&
3553 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3554 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3555 kern_psignal(p, sig);
3556 PROC_UNLOCK(p);
3557 }
3558 PGRP_UNLOCK(sigio->sio_pgrp);
3559 }
3560 SIGIO_UNLOCK();
3561 }
3562
3563 static int
filt_sigattach(struct knote * kn)3564 filt_sigattach(struct knote *kn)
3565 {
3566 struct proc *p = curproc;
3567
3568 kn->kn_ptr.p_proc = p;
3569 kn->kn_flags |= EV_CLEAR; /* automatically set */
3570
3571 knlist_add(&p->p_klist, kn, 0);
3572
3573 return (0);
3574 }
3575
3576 static void
filt_sigdetach(struct knote * kn)3577 filt_sigdetach(struct knote *kn)
3578 {
3579 struct proc *p = kn->kn_ptr.p_proc;
3580
3581 knlist_remove(&p->p_klist, kn, 0);
3582 }
3583
3584 /*
3585 * signal knotes are shared with proc knotes, so we apply a mask to
3586 * the hint in order to differentiate them from process hints. This
3587 * could be avoided by using a signal-specific knote list, but probably
3588 * isn't worth the trouble.
3589 */
3590 static int
filt_signal(struct knote * kn,long hint)3591 filt_signal(struct knote *kn, long hint)
3592 {
3593
3594 if (hint & NOTE_SIGNAL) {
3595 hint &= ~NOTE_SIGNAL;
3596
3597 if (kn->kn_id == hint)
3598 kn->kn_data++;
3599 }
3600 return (kn->kn_data != 0);
3601 }
3602
3603 struct sigacts *
sigacts_alloc(void)3604 sigacts_alloc(void)
3605 {
3606 struct sigacts *ps;
3607
3608 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3609 ps->ps_refcnt = 1;
3610 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3611 return (ps);
3612 }
3613
3614 void
sigacts_free(struct sigacts * ps)3615 sigacts_free(struct sigacts *ps)
3616 {
3617
3618 if (refcount_release(&ps->ps_refcnt) == 0)
3619 return;
3620 mtx_destroy(&ps->ps_mtx);
3621 free(ps, M_SUBPROC);
3622 }
3623
3624 struct sigacts *
sigacts_hold(struct sigacts * ps)3625 sigacts_hold(struct sigacts *ps)
3626 {
3627
3628 refcount_acquire(&ps->ps_refcnt);
3629 return (ps);
3630 }
3631
3632 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3633 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3634 {
3635
3636 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3637 mtx_lock(&src->ps_mtx);
3638 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3639 mtx_unlock(&src->ps_mtx);
3640 }
3641
3642 int
sigacts_shared(struct sigacts * ps)3643 sigacts_shared(struct sigacts *ps)
3644 {
3645
3646 return (ps->ps_refcnt > 1);
3647 }
3648