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/9/sys/kern/kern_sig.c 289800 2015-10-23 07:44:03Z avg $");
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/systm.h>
48 #include <sys/signalvar.h>
49 #include <sys/vnode.h>
50 #include <sys/acct.h>
51 #include <sys/capability.h>
52 #include <sys/condvar.h>
53 #include <sys/event.h>
54 #include <sys/fcntl.h>
55 #include <sys/imgact.h>
56 #include <sys/kernel.h>
57 #include <sys/ktr.h>
58 #include <sys/ktrace.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mutex.h>
62 #include <sys/namei.h>
63 #include <sys/proc.h>
64 #include <sys/procdesc.h>
65 #include <sys/posix4.h>
66 #include <sys/pioctl.h>
67 #include <sys/racct.h>
68 #include <sys/resourcevar.h>
69 #include <sys/sdt.h>
70 #include <sys/sbuf.h>
71 #include <sys/sleepqueue.h>
72 #include <sys/smp.h>
73 #include <sys/stat.h>
74 #include <sys/sx.h>
75 #include <sys/syscallsubr.h>
76 #include <sys/sysctl.h>
77 #include <sys/sysent.h>
78 #include <sys/syslog.h>
79 #include <sys/sysproto.h>
80 #include <sys/timers.h>
81 #include <sys/unistd.h>
82 #include <sys/wait.h>
83 #include <vm/vm.h>
84 #include <vm/vm_extern.h>
85 #include <vm/uma.h>
86
87 #include <sys/jail.h>
88
89 #include <machine/cpu.h>
90
91 #include <security/audit/audit.h>
92
93 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
94
95 SDT_PROVIDER_DECLARE(proc);
96 SDT_PROBE_DEFINE3(proc, kernel, , signal__send, "struct thread *",
97 "struct proc *", "int");
98 SDT_PROBE_DEFINE2(proc, kernel, , signal__clear, "int",
99 "ksiginfo_t *");
100 SDT_PROBE_DEFINE3(proc, kernel, , signal__discard,
101 "struct thread *", "struct proc *", "int");
102
103 static int coredump(struct thread *);
104 static char *expand_name(const char *, uid_t, pid_t, struct thread *, int);
105 static int killpg1(struct thread *td, int sig, int pgid, int all,
106 ksiginfo_t *ksi);
107 static int issignal(struct thread *td, int stop_allowed);
108 static int sigprop(int sig);
109 static void tdsigwakeup(struct thread *, int, sig_t, int);
110 static void sig_suspend_threads(struct thread *, struct proc *, int);
111 static int filt_sigattach(struct knote *kn);
112 static void filt_sigdetach(struct knote *kn);
113 static int filt_signal(struct knote *kn, long hint);
114 static struct thread *sigtd(struct proc *p, int sig, int prop);
115 static void sigqueue_start(void);
116
117 static uma_zone_t ksiginfo_zone = NULL;
118 struct filterops sig_filtops = {
119 .f_isfd = 0,
120 .f_attach = filt_sigattach,
121 .f_detach = filt_sigdetach,
122 .f_event = filt_signal,
123 };
124
125 static int kern_logsigexit = 1;
126 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
127 &kern_logsigexit, 0,
128 "Log processes quitting on abnormal signals to syslog(3)");
129
130 static int kern_forcesigexit = 1;
131 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
132 &kern_forcesigexit, 0, "Force trap signal to be handled");
133
134 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0,
135 "POSIX real time signal");
136
137 static int max_pending_per_proc = 128;
138 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
139 &max_pending_per_proc, 0, "Max pending signals per proc");
140
141 static int preallocate_siginfo = 1024;
142 TUNABLE_INT("kern.sigqueue.preallocate", &preallocate_siginfo);
143 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RD,
144 &preallocate_siginfo, 0, "Preallocated signal memory size");
145
146 static int signal_overflow = 0;
147 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
148 &signal_overflow, 0, "Number of signals overflew");
149
150 static int signal_alloc_fail = 0;
151 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
152 &signal_alloc_fail, 0, "signals failed to be allocated");
153
154 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
155
156 /*
157 * Policy -- Can ucred cr1 send SIGIO to process cr2?
158 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
159 * in the right situations.
160 */
161 #define CANSIGIO(cr1, cr2) \
162 ((cr1)->cr_uid == 0 || \
163 (cr1)->cr_ruid == (cr2)->cr_ruid || \
164 (cr1)->cr_uid == (cr2)->cr_ruid || \
165 (cr1)->cr_ruid == (cr2)->cr_uid || \
166 (cr1)->cr_uid == (cr2)->cr_uid)
167
168 static int sugid_coredump;
169 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
170 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
171
172 static int do_coredump = 1;
173 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
174 &do_coredump, 0, "Enable/Disable coredumps");
175
176 static int set_core_nodump_flag = 0;
177 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
178 0, "Enable setting the NODUMP flag on coredump files");
179
180 /*
181 * Signal properties and actions.
182 * The array below categorizes the signals and their default actions
183 * according to the following properties:
184 */
185 #define SA_KILL 0x01 /* terminates process by default */
186 #define SA_CORE 0x02 /* ditto and coredumps */
187 #define SA_STOP 0x04 /* suspend process */
188 #define SA_TTYSTOP 0x08 /* ditto, from tty */
189 #define SA_IGNORE 0x10 /* ignore by default */
190 #define SA_CONT 0x20 /* continue if suspended */
191 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
192 #define SA_PROC 0x80 /* deliverable to any thread */
193
194 static int sigproptbl[NSIG] = {
195 SA_KILL|SA_PROC, /* SIGHUP */
196 SA_KILL|SA_PROC, /* SIGINT */
197 SA_KILL|SA_CORE|SA_PROC, /* SIGQUIT */
198 SA_KILL|SA_CORE, /* SIGILL */
199 SA_KILL|SA_CORE, /* SIGTRAP */
200 SA_KILL|SA_CORE, /* SIGABRT */
201 SA_KILL|SA_CORE|SA_PROC, /* SIGEMT */
202 SA_KILL|SA_CORE, /* SIGFPE */
203 SA_KILL|SA_PROC, /* SIGKILL */
204 SA_KILL|SA_CORE, /* SIGBUS */
205 SA_KILL|SA_CORE, /* SIGSEGV */
206 SA_KILL|SA_CORE, /* SIGSYS */
207 SA_KILL|SA_PROC, /* SIGPIPE */
208 SA_KILL|SA_PROC, /* SIGALRM */
209 SA_KILL|SA_PROC, /* SIGTERM */
210 SA_IGNORE|SA_PROC, /* SIGURG */
211 SA_STOP|SA_PROC, /* SIGSTOP */
212 SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTSTP */
213 SA_IGNORE|SA_CONT|SA_PROC, /* SIGCONT */
214 SA_IGNORE|SA_PROC, /* SIGCHLD */
215 SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTIN */
216 SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTOU */
217 SA_IGNORE|SA_PROC, /* SIGIO */
218 SA_KILL, /* SIGXCPU */
219 SA_KILL, /* SIGXFSZ */
220 SA_KILL|SA_PROC, /* SIGVTALRM */
221 SA_KILL|SA_PROC, /* SIGPROF */
222 SA_IGNORE|SA_PROC, /* SIGWINCH */
223 SA_IGNORE|SA_PROC, /* SIGINFO */
224 SA_KILL|SA_PROC, /* SIGUSR1 */
225 SA_KILL|SA_PROC, /* SIGUSR2 */
226 };
227
228 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
229
230 static void
sigqueue_start(void)231 sigqueue_start(void)
232 {
233 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
234 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
235 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
236 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
237 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
238 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
239 }
240
241 ksiginfo_t *
ksiginfo_alloc(int wait)242 ksiginfo_alloc(int wait)
243 {
244 int flags;
245
246 flags = M_ZERO;
247 if (! wait)
248 flags |= M_NOWAIT;
249 if (ksiginfo_zone != NULL)
250 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
251 return (NULL);
252 }
253
254 void
ksiginfo_free(ksiginfo_t * ksi)255 ksiginfo_free(ksiginfo_t *ksi)
256 {
257 uma_zfree(ksiginfo_zone, ksi);
258 }
259
260 static __inline int
ksiginfo_tryfree(ksiginfo_t * ksi)261 ksiginfo_tryfree(ksiginfo_t *ksi)
262 {
263 if (!(ksi->ksi_flags & KSI_EXT)) {
264 uma_zfree(ksiginfo_zone, ksi);
265 return (1);
266 }
267 return (0);
268 }
269
270 void
sigqueue_init(sigqueue_t * list,struct proc * p)271 sigqueue_init(sigqueue_t *list, struct proc *p)
272 {
273 SIGEMPTYSET(list->sq_signals);
274 SIGEMPTYSET(list->sq_kill);
275 TAILQ_INIT(&list->sq_list);
276 list->sq_proc = p;
277 list->sq_flags = SQ_INIT;
278 }
279
280 /*
281 * Get a signal's ksiginfo.
282 * Return:
283 * 0 - signal not found
284 * others - signal number
285 */
286 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)287 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
288 {
289 struct proc *p = sq->sq_proc;
290 struct ksiginfo *ksi, *next;
291 int count = 0;
292
293 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
294
295 if (!SIGISMEMBER(sq->sq_signals, signo))
296 return (0);
297
298 if (SIGISMEMBER(sq->sq_kill, signo)) {
299 count++;
300 SIGDELSET(sq->sq_kill, signo);
301 }
302
303 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
304 if (ksi->ksi_signo == signo) {
305 if (count == 0) {
306 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
307 ksi->ksi_sigq = NULL;
308 ksiginfo_copy(ksi, si);
309 if (ksiginfo_tryfree(ksi) && p != NULL)
310 p->p_pendingcnt--;
311 }
312 if (++count > 1)
313 break;
314 }
315 }
316
317 if (count <= 1)
318 SIGDELSET(sq->sq_signals, signo);
319 si->ksi_signo = signo;
320 return (signo);
321 }
322
323 void
sigqueue_take(ksiginfo_t * ksi)324 sigqueue_take(ksiginfo_t *ksi)
325 {
326 struct ksiginfo *kp;
327 struct proc *p;
328 sigqueue_t *sq;
329
330 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
331 return;
332
333 p = sq->sq_proc;
334 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
335 ksi->ksi_sigq = NULL;
336 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
337 p->p_pendingcnt--;
338
339 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
340 kp = TAILQ_NEXT(kp, ksi_link)) {
341 if (kp->ksi_signo == ksi->ksi_signo)
342 break;
343 }
344 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo))
345 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
346 }
347
348 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)349 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
350 {
351 struct proc *p = sq->sq_proc;
352 struct ksiginfo *ksi;
353 int ret = 0;
354
355 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
356
357 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
358 SIGADDSET(sq->sq_kill, signo);
359 goto out_set_bit;
360 }
361
362 /* directly insert the ksi, don't copy it */
363 if (si->ksi_flags & KSI_INS) {
364 if (si->ksi_flags & KSI_HEAD)
365 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
366 else
367 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
368 si->ksi_sigq = sq;
369 goto out_set_bit;
370 }
371
372 if (__predict_false(ksiginfo_zone == NULL)) {
373 SIGADDSET(sq->sq_kill, signo);
374 goto out_set_bit;
375 }
376
377 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
378 signal_overflow++;
379 ret = EAGAIN;
380 } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
381 signal_alloc_fail++;
382 ret = EAGAIN;
383 } else {
384 if (p != NULL)
385 p->p_pendingcnt++;
386 ksiginfo_copy(si, ksi);
387 ksi->ksi_signo = signo;
388 if (si->ksi_flags & KSI_HEAD)
389 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
390 else
391 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
392 ksi->ksi_sigq = sq;
393 }
394
395 if ((si->ksi_flags & KSI_TRAP) != 0 ||
396 (si->ksi_flags & KSI_SIGQ) == 0) {
397 if (ret != 0)
398 SIGADDSET(sq->sq_kill, signo);
399 ret = 0;
400 goto out_set_bit;
401 }
402
403 if (ret != 0)
404 return (ret);
405
406 out_set_bit:
407 SIGADDSET(sq->sq_signals, signo);
408 return (ret);
409 }
410
411 void
sigqueue_flush(sigqueue_t * sq)412 sigqueue_flush(sigqueue_t *sq)
413 {
414 struct proc *p = sq->sq_proc;
415 ksiginfo_t *ksi;
416
417 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
418
419 if (p != NULL)
420 PROC_LOCK_ASSERT(p, MA_OWNED);
421
422 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
423 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
424 ksi->ksi_sigq = NULL;
425 if (ksiginfo_tryfree(ksi) && p != NULL)
426 p->p_pendingcnt--;
427 }
428
429 SIGEMPTYSET(sq->sq_signals);
430 SIGEMPTYSET(sq->sq_kill);
431 }
432
433 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)434 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
435 {
436 sigset_t tmp;
437 struct proc *p1, *p2;
438 ksiginfo_t *ksi, *next;
439
440 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
441 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
442 p1 = src->sq_proc;
443 p2 = dst->sq_proc;
444 /* Move siginfo to target list */
445 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
446 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
447 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
448 if (p1 != NULL)
449 p1->p_pendingcnt--;
450 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
451 ksi->ksi_sigq = dst;
452 if (p2 != NULL)
453 p2->p_pendingcnt++;
454 }
455 }
456
457 /* Move pending bits to target list */
458 tmp = src->sq_kill;
459 SIGSETAND(tmp, *set);
460 SIGSETOR(dst->sq_kill, tmp);
461 SIGSETNAND(src->sq_kill, tmp);
462
463 tmp = src->sq_signals;
464 SIGSETAND(tmp, *set);
465 SIGSETOR(dst->sq_signals, tmp);
466 SIGSETNAND(src->sq_signals, tmp);
467 }
468
469 #if 0
470 static void
471 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
472 {
473 sigset_t set;
474
475 SIGEMPTYSET(set);
476 SIGADDSET(set, signo);
477 sigqueue_move_set(src, dst, &set);
478 }
479 #endif
480
481 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)482 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
483 {
484 struct proc *p = sq->sq_proc;
485 ksiginfo_t *ksi, *next;
486
487 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
488
489 /* Remove siginfo queue */
490 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
491 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
492 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
493 ksi->ksi_sigq = NULL;
494 if (ksiginfo_tryfree(ksi) && p != NULL)
495 p->p_pendingcnt--;
496 }
497 }
498 SIGSETNAND(sq->sq_kill, *set);
499 SIGSETNAND(sq->sq_signals, *set);
500 }
501
502 void
sigqueue_delete(sigqueue_t * sq,int signo)503 sigqueue_delete(sigqueue_t *sq, int signo)
504 {
505 sigset_t set;
506
507 SIGEMPTYSET(set);
508 SIGADDSET(set, signo);
509 sigqueue_delete_set(sq, &set);
510 }
511
512 /* Remove a set of signals for a process */
513 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)514 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
515 {
516 sigqueue_t worklist;
517 struct thread *td0;
518
519 PROC_LOCK_ASSERT(p, MA_OWNED);
520
521 sigqueue_init(&worklist, NULL);
522 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
523
524 FOREACH_THREAD_IN_PROC(p, td0)
525 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
526
527 sigqueue_flush(&worklist);
528 }
529
530 void
sigqueue_delete_proc(struct proc * p,int signo)531 sigqueue_delete_proc(struct proc *p, int signo)
532 {
533 sigset_t set;
534
535 SIGEMPTYSET(set);
536 SIGADDSET(set, signo);
537 sigqueue_delete_set_proc(p, &set);
538 }
539
540 static void
sigqueue_delete_stopmask_proc(struct proc * p)541 sigqueue_delete_stopmask_proc(struct proc *p)
542 {
543 sigset_t set;
544
545 SIGEMPTYSET(set);
546 SIGADDSET(set, SIGSTOP);
547 SIGADDSET(set, SIGTSTP);
548 SIGADDSET(set, SIGTTIN);
549 SIGADDSET(set, SIGTTOU);
550 sigqueue_delete_set_proc(p, &set);
551 }
552
553 /*
554 * Determine signal that should be delivered to process p, the current
555 * process, 0 if none. If there is a pending stop signal with default
556 * action, the process stops in issignal().
557 */
558 int
cursig(struct thread * td,int stop_allowed)559 cursig(struct thread *td, int stop_allowed)
560 {
561 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
562 KASSERT(stop_allowed == SIG_STOP_ALLOWED ||
563 stop_allowed == SIG_STOP_NOT_ALLOWED, ("cursig: stop_allowed"));
564 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
565 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
566 return (SIGPENDING(td) ? issignal(td, stop_allowed) : 0);
567 }
568
569 /*
570 * Arrange for ast() to handle unmasked pending signals on return to user
571 * mode. This must be called whenever a signal is added to td_sigqueue or
572 * unmasked in td_sigmask.
573 */
574 void
signotify(struct thread * td)575 signotify(struct thread *td)
576 {
577 struct proc *p;
578
579 p = td->td_proc;
580
581 PROC_LOCK_ASSERT(p, MA_OWNED);
582
583 if (SIGPENDING(td)) {
584 thread_lock(td);
585 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
586 thread_unlock(td);
587 }
588 }
589
590 int
sigonstack(size_t sp)591 sigonstack(size_t sp)
592 {
593 struct thread *td = curthread;
594
595 return ((td->td_pflags & TDP_ALTSTACK) ?
596 #if defined(COMPAT_43)
597 ((td->td_sigstk.ss_size == 0) ?
598 (td->td_sigstk.ss_flags & SS_ONSTACK) :
599 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
600 #else
601 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
602 #endif
603 : 0);
604 }
605
606 static __inline int
sigprop(int sig)607 sigprop(int sig)
608 {
609
610 if (sig > 0 && sig < NSIG)
611 return (sigproptbl[_SIG_IDX(sig)]);
612 return (0);
613 }
614
615 int
sig_ffs(sigset_t * set)616 sig_ffs(sigset_t *set)
617 {
618 int i;
619
620 for (i = 0; i < _SIG_WORDS; i++)
621 if (set->__bits[i])
622 return (ffs(set->__bits[i]) + (i * 32));
623 return (0);
624 }
625
626 /*
627 * kern_sigaction
628 * sigaction
629 * freebsd4_sigaction
630 * osigaction
631 */
632 int
kern_sigaction(td,sig,act,oact,flags)633 kern_sigaction(td, sig, act, oact, flags)
634 struct thread *td;
635 register int sig;
636 struct sigaction *act, *oact;
637 int flags;
638 {
639 struct sigacts *ps;
640 struct proc *p = td->td_proc;
641
642 if (!_SIG_VALID(sig))
643 return (EINVAL);
644
645 PROC_LOCK(p);
646 ps = p->p_sigacts;
647 mtx_lock(&ps->ps_mtx);
648 if (oact) {
649 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
650 oact->sa_flags = 0;
651 if (SIGISMEMBER(ps->ps_sigonstack, sig))
652 oact->sa_flags |= SA_ONSTACK;
653 if (!SIGISMEMBER(ps->ps_sigintr, sig))
654 oact->sa_flags |= SA_RESTART;
655 if (SIGISMEMBER(ps->ps_sigreset, sig))
656 oact->sa_flags |= SA_RESETHAND;
657 if (SIGISMEMBER(ps->ps_signodefer, sig))
658 oact->sa_flags |= SA_NODEFER;
659 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
660 oact->sa_flags |= SA_SIGINFO;
661 oact->sa_sigaction =
662 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
663 } else
664 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
665 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
666 oact->sa_flags |= SA_NOCLDSTOP;
667 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
668 oact->sa_flags |= SA_NOCLDWAIT;
669 }
670 if (act) {
671 if ((sig == SIGKILL || sig == SIGSTOP) &&
672 act->sa_handler != SIG_DFL) {
673 mtx_unlock(&ps->ps_mtx);
674 PROC_UNLOCK(p);
675 return (EINVAL);
676 }
677
678 /*
679 * Change setting atomically.
680 */
681
682 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
683 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
684 if (act->sa_flags & SA_SIGINFO) {
685 ps->ps_sigact[_SIG_IDX(sig)] =
686 (__sighandler_t *)act->sa_sigaction;
687 SIGADDSET(ps->ps_siginfo, sig);
688 } else {
689 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
690 SIGDELSET(ps->ps_siginfo, sig);
691 }
692 if (!(act->sa_flags & SA_RESTART))
693 SIGADDSET(ps->ps_sigintr, sig);
694 else
695 SIGDELSET(ps->ps_sigintr, sig);
696 if (act->sa_flags & SA_ONSTACK)
697 SIGADDSET(ps->ps_sigonstack, sig);
698 else
699 SIGDELSET(ps->ps_sigonstack, sig);
700 if (act->sa_flags & SA_RESETHAND)
701 SIGADDSET(ps->ps_sigreset, sig);
702 else
703 SIGDELSET(ps->ps_sigreset, sig);
704 if (act->sa_flags & SA_NODEFER)
705 SIGADDSET(ps->ps_signodefer, sig);
706 else
707 SIGDELSET(ps->ps_signodefer, sig);
708 if (sig == SIGCHLD) {
709 if (act->sa_flags & SA_NOCLDSTOP)
710 ps->ps_flag |= PS_NOCLDSTOP;
711 else
712 ps->ps_flag &= ~PS_NOCLDSTOP;
713 if (act->sa_flags & SA_NOCLDWAIT) {
714 /*
715 * Paranoia: since SA_NOCLDWAIT is implemented
716 * by reparenting the dying child to PID 1 (and
717 * trust it to reap the zombie), PID 1 itself
718 * is forbidden to set SA_NOCLDWAIT.
719 */
720 if (p->p_pid == 1)
721 ps->ps_flag &= ~PS_NOCLDWAIT;
722 else
723 ps->ps_flag |= PS_NOCLDWAIT;
724 } else
725 ps->ps_flag &= ~PS_NOCLDWAIT;
726 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
727 ps->ps_flag |= PS_CLDSIGIGN;
728 else
729 ps->ps_flag &= ~PS_CLDSIGIGN;
730 }
731 /*
732 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
733 * and for signals set to SIG_DFL where the default is to
734 * ignore. However, don't put SIGCONT in ps_sigignore, as we
735 * have to restart the process.
736 */
737 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
738 (sigprop(sig) & SA_IGNORE &&
739 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
740 /* never to be seen again */
741 sigqueue_delete_proc(p, sig);
742 if (sig != SIGCONT)
743 /* easier in psignal */
744 SIGADDSET(ps->ps_sigignore, sig);
745 SIGDELSET(ps->ps_sigcatch, sig);
746 } else {
747 SIGDELSET(ps->ps_sigignore, sig);
748 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
749 SIGDELSET(ps->ps_sigcatch, sig);
750 else
751 SIGADDSET(ps->ps_sigcatch, sig);
752 }
753 #ifdef COMPAT_FREEBSD4
754 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
755 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
756 (flags & KSA_FREEBSD4) == 0)
757 SIGDELSET(ps->ps_freebsd4, sig);
758 else
759 SIGADDSET(ps->ps_freebsd4, sig);
760 #endif
761 #ifdef COMPAT_43
762 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
763 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
764 (flags & KSA_OSIGSET) == 0)
765 SIGDELSET(ps->ps_osigset, sig);
766 else
767 SIGADDSET(ps->ps_osigset, sig);
768 #endif
769 }
770 mtx_unlock(&ps->ps_mtx);
771 PROC_UNLOCK(p);
772 return (0);
773 }
774
775 #ifndef _SYS_SYSPROTO_H_
776 struct sigaction_args {
777 int sig;
778 struct sigaction *act;
779 struct sigaction *oact;
780 };
781 #endif
782 int
sys_sigaction(td,uap)783 sys_sigaction(td, uap)
784 struct thread *td;
785 register struct sigaction_args *uap;
786 {
787 struct sigaction act, oact;
788 register struct sigaction *actp, *oactp;
789 int error;
790
791 actp = (uap->act != NULL) ? &act : NULL;
792 oactp = (uap->oact != NULL) ? &oact : NULL;
793 if (actp) {
794 error = copyin(uap->act, actp, sizeof(act));
795 if (error)
796 return (error);
797 }
798 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
799 if (oactp && !error)
800 error = copyout(oactp, uap->oact, sizeof(oact));
801 return (error);
802 }
803
804 #ifdef COMPAT_FREEBSD4
805 #ifndef _SYS_SYSPROTO_H_
806 struct freebsd4_sigaction_args {
807 int sig;
808 struct sigaction *act;
809 struct sigaction *oact;
810 };
811 #endif
812 int
freebsd4_sigaction(td,uap)813 freebsd4_sigaction(td, uap)
814 struct thread *td;
815 register struct freebsd4_sigaction_args *uap;
816 {
817 struct sigaction act, oact;
818 register struct sigaction *actp, *oactp;
819 int error;
820
821
822 actp = (uap->act != NULL) ? &act : NULL;
823 oactp = (uap->oact != NULL) ? &oact : NULL;
824 if (actp) {
825 error = copyin(uap->act, actp, sizeof(act));
826 if (error)
827 return (error);
828 }
829 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
830 if (oactp && !error)
831 error = copyout(oactp, uap->oact, sizeof(oact));
832 return (error);
833 }
834 #endif /* COMAPT_FREEBSD4 */
835
836 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
837 #ifndef _SYS_SYSPROTO_H_
838 struct osigaction_args {
839 int signum;
840 struct osigaction *nsa;
841 struct osigaction *osa;
842 };
843 #endif
844 int
osigaction(td,uap)845 osigaction(td, uap)
846 struct thread *td;
847 register struct osigaction_args *uap;
848 {
849 struct osigaction sa;
850 struct sigaction nsa, osa;
851 register struct sigaction *nsap, *osap;
852 int error;
853
854 if (uap->signum <= 0 || uap->signum >= ONSIG)
855 return (EINVAL);
856
857 nsap = (uap->nsa != NULL) ? &nsa : NULL;
858 osap = (uap->osa != NULL) ? &osa : NULL;
859
860 if (nsap) {
861 error = copyin(uap->nsa, &sa, sizeof(sa));
862 if (error)
863 return (error);
864 nsap->sa_handler = sa.sa_handler;
865 nsap->sa_flags = sa.sa_flags;
866 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
867 }
868 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
869 if (osap && !error) {
870 sa.sa_handler = osap->sa_handler;
871 sa.sa_flags = osap->sa_flags;
872 SIG2OSIG(osap->sa_mask, sa.sa_mask);
873 error = copyout(&sa, uap->osa, sizeof(sa));
874 }
875 return (error);
876 }
877
878 #if !defined(__i386__)
879 /* Avoid replicating the same stub everywhere */
880 int
osigreturn(td,uap)881 osigreturn(td, uap)
882 struct thread *td;
883 struct osigreturn_args *uap;
884 {
885
886 return (nosys(td, (struct nosys_args *)uap));
887 }
888 #endif
889 #endif /* COMPAT_43 */
890
891 /*
892 * Initialize signal state for process 0;
893 * set to ignore signals that are ignored by default.
894 */
895 void
siginit(p)896 siginit(p)
897 struct proc *p;
898 {
899 register int i;
900 struct sigacts *ps;
901
902 PROC_LOCK(p);
903 ps = p->p_sigacts;
904 mtx_lock(&ps->ps_mtx);
905 for (i = 1; i <= NSIG; i++)
906 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
907 SIGADDSET(ps->ps_sigignore, i);
908 mtx_unlock(&ps->ps_mtx);
909 PROC_UNLOCK(p);
910 }
911
912 /*
913 * Reset signals for an exec of the specified process.
914 */
915 void
execsigs(struct proc * p)916 execsigs(struct proc *p)
917 {
918 struct sigacts *ps;
919 int sig;
920 struct thread *td;
921
922 /*
923 * Reset caught signals. Held signals remain held
924 * through td_sigmask (unless they were caught,
925 * and are now ignored by default).
926 */
927 PROC_LOCK_ASSERT(p, MA_OWNED);
928 td = FIRST_THREAD_IN_PROC(p);
929 ps = p->p_sigacts;
930 mtx_lock(&ps->ps_mtx);
931 while (SIGNOTEMPTY(ps->ps_sigcatch)) {
932 sig = sig_ffs(&ps->ps_sigcatch);
933 SIGDELSET(ps->ps_sigcatch, sig);
934 if (sigprop(sig) & SA_IGNORE) {
935 if (sig != SIGCONT)
936 SIGADDSET(ps->ps_sigignore, sig);
937 sigqueue_delete_proc(p, sig);
938 }
939 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
940 }
941 /*
942 * Reset stack state to the user stack.
943 * Clear set of signals caught on the signal stack.
944 */
945 td->td_sigstk.ss_flags = SS_DISABLE;
946 td->td_sigstk.ss_size = 0;
947 td->td_sigstk.ss_sp = 0;
948 td->td_pflags &= ~TDP_ALTSTACK;
949 /*
950 * Reset no zombies if child dies flag as Solaris does.
951 */
952 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
953 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
954 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
955 mtx_unlock(&ps->ps_mtx);
956 }
957
958 /*
959 * kern_sigprocmask()
960 *
961 * Manipulate signal mask.
962 */
963 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)964 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
965 int flags)
966 {
967 sigset_t new_block, oset1;
968 struct proc *p;
969 int error;
970
971 p = td->td_proc;
972 if (!(flags & SIGPROCMASK_PROC_LOCKED))
973 PROC_LOCK(p);
974 if (oset != NULL)
975 *oset = td->td_sigmask;
976
977 error = 0;
978 if (set != NULL) {
979 switch (how) {
980 case SIG_BLOCK:
981 SIG_CANTMASK(*set);
982 oset1 = td->td_sigmask;
983 SIGSETOR(td->td_sigmask, *set);
984 new_block = td->td_sigmask;
985 SIGSETNAND(new_block, oset1);
986 break;
987 case SIG_UNBLOCK:
988 SIGSETNAND(td->td_sigmask, *set);
989 signotify(td);
990 goto out;
991 case SIG_SETMASK:
992 SIG_CANTMASK(*set);
993 oset1 = td->td_sigmask;
994 if (flags & SIGPROCMASK_OLD)
995 SIGSETLO(td->td_sigmask, *set);
996 else
997 td->td_sigmask = *set;
998 new_block = td->td_sigmask;
999 SIGSETNAND(new_block, oset1);
1000 signotify(td);
1001 break;
1002 default:
1003 error = EINVAL;
1004 goto out;
1005 }
1006
1007 /*
1008 * The new_block set contains signals that were not previously
1009 * blocked, but are blocked now.
1010 *
1011 * In case we block any signal that was not previously blocked
1012 * for td, and process has the signal pending, try to schedule
1013 * signal delivery to some thread that does not block the
1014 * signal, possibly waking it up.
1015 */
1016 if (p->p_numthreads != 1)
1017 reschedule_signals(p, new_block, flags);
1018 }
1019
1020 out:
1021 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1022 PROC_UNLOCK(p);
1023 return (error);
1024 }
1025
1026 #ifndef _SYS_SYSPROTO_H_
1027 struct sigprocmask_args {
1028 int how;
1029 const sigset_t *set;
1030 sigset_t *oset;
1031 };
1032 #endif
1033 int
sys_sigprocmask(td,uap)1034 sys_sigprocmask(td, uap)
1035 register struct thread *td;
1036 struct sigprocmask_args *uap;
1037 {
1038 sigset_t set, oset;
1039 sigset_t *setp, *osetp;
1040 int error;
1041
1042 setp = (uap->set != NULL) ? &set : NULL;
1043 osetp = (uap->oset != NULL) ? &oset : NULL;
1044 if (setp) {
1045 error = copyin(uap->set, setp, sizeof(set));
1046 if (error)
1047 return (error);
1048 }
1049 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1050 if (osetp && !error) {
1051 error = copyout(osetp, uap->oset, sizeof(oset));
1052 }
1053 return (error);
1054 }
1055
1056 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1057 #ifndef _SYS_SYSPROTO_H_
1058 struct osigprocmask_args {
1059 int how;
1060 osigset_t mask;
1061 };
1062 #endif
1063 int
osigprocmask(td,uap)1064 osigprocmask(td, uap)
1065 register struct thread *td;
1066 struct osigprocmask_args *uap;
1067 {
1068 sigset_t set, oset;
1069 int error;
1070
1071 OSIG2SIG(uap->mask, set);
1072 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1073 SIG2OSIG(oset, td->td_retval[0]);
1074 return (error);
1075 }
1076 #endif /* COMPAT_43 */
1077
1078 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1079 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1080 {
1081 ksiginfo_t ksi;
1082 sigset_t set;
1083 int error;
1084
1085 error = copyin(uap->set, &set, sizeof(set));
1086 if (error) {
1087 td->td_retval[0] = error;
1088 return (0);
1089 }
1090
1091 error = kern_sigtimedwait(td, set, &ksi, NULL);
1092 if (error) {
1093 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1094 error = ERESTART;
1095 if (error == ERESTART)
1096 return (error);
1097 td->td_retval[0] = error;
1098 return (0);
1099 }
1100
1101 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1102 td->td_retval[0] = error;
1103 return (0);
1104 }
1105
1106 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1107 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1108 {
1109 struct timespec ts;
1110 struct timespec *timeout;
1111 sigset_t set;
1112 ksiginfo_t ksi;
1113 int error;
1114
1115 if (uap->timeout) {
1116 error = copyin(uap->timeout, &ts, sizeof(ts));
1117 if (error)
1118 return (error);
1119
1120 timeout = &ts;
1121 } else
1122 timeout = NULL;
1123
1124 error = copyin(uap->set, &set, sizeof(set));
1125 if (error)
1126 return (error);
1127
1128 error = kern_sigtimedwait(td, set, &ksi, timeout);
1129 if (error)
1130 return (error);
1131
1132 if (uap->info)
1133 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1134
1135 if (error == 0)
1136 td->td_retval[0] = ksi.ksi_signo;
1137 return (error);
1138 }
1139
1140 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1141 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1142 {
1143 ksiginfo_t ksi;
1144 sigset_t set;
1145 int error;
1146
1147 error = copyin(uap->set, &set, sizeof(set));
1148 if (error)
1149 return (error);
1150
1151 error = kern_sigtimedwait(td, set, &ksi, NULL);
1152 if (error)
1153 return (error);
1154
1155 if (uap->info)
1156 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1157
1158 if (error == 0)
1159 td->td_retval[0] = ksi.ksi_signo;
1160 return (error);
1161 }
1162
1163 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1164 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1165 struct timespec *timeout)
1166 {
1167 struct sigacts *ps;
1168 sigset_t saved_mask, new_block;
1169 struct proc *p;
1170 int error, sig, timo, timevalid = 0;
1171 struct timespec rts, ets, ts;
1172 struct timeval tv;
1173
1174 p = td->td_proc;
1175 error = 0;
1176 ets.tv_sec = 0;
1177 ets.tv_nsec = 0;
1178
1179 if (timeout != NULL) {
1180 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1181 timevalid = 1;
1182 getnanouptime(&rts);
1183 ets = rts;
1184 timespecadd(&ets, timeout);
1185 }
1186 }
1187 ksiginfo_init(ksi);
1188 /* Some signals can not be waited for. */
1189 SIG_CANTMASK(waitset);
1190 ps = p->p_sigacts;
1191 PROC_LOCK(p);
1192 saved_mask = td->td_sigmask;
1193 SIGSETNAND(td->td_sigmask, waitset);
1194 for (;;) {
1195 mtx_lock(&ps->ps_mtx);
1196 sig = cursig(td, SIG_STOP_ALLOWED);
1197 mtx_unlock(&ps->ps_mtx);
1198 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1199 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1200 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1201 error = 0;
1202 break;
1203 }
1204 }
1205
1206 if (error != 0)
1207 break;
1208
1209 /*
1210 * POSIX says this must be checked after looking for pending
1211 * signals.
1212 */
1213 if (timeout != NULL) {
1214 if (!timevalid) {
1215 error = EINVAL;
1216 break;
1217 }
1218 getnanouptime(&rts);
1219 if (timespeccmp(&rts, &ets, >=)) {
1220 error = EAGAIN;
1221 break;
1222 }
1223 ts = ets;
1224 timespecsub(&ts, &rts);
1225 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1226 timo = tvtohz(&tv);
1227 } else {
1228 timo = 0;
1229 }
1230
1231 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
1232
1233 if (timeout != NULL) {
1234 if (error == ERESTART) {
1235 /* Timeout can not be restarted. */
1236 error = EINTR;
1237 } else if (error == EAGAIN) {
1238 /* We will calculate timeout by ourself. */
1239 error = 0;
1240 }
1241 }
1242 }
1243
1244 new_block = saved_mask;
1245 SIGSETNAND(new_block, td->td_sigmask);
1246 td->td_sigmask = saved_mask;
1247 /*
1248 * Fewer signals can be delivered to us, reschedule signal
1249 * notification.
1250 */
1251 if (p->p_numthreads != 1)
1252 reschedule_signals(p, new_block, 0);
1253
1254 if (error == 0) {
1255 SDT_PROBE2(proc, kernel, , signal__clear, sig, ksi);
1256
1257 if (ksi->ksi_code == SI_TIMER)
1258 itimer_accept(p, ksi->ksi_timerid, ksi);
1259
1260 #ifdef KTRACE
1261 if (KTRPOINT(td, KTR_PSIG)) {
1262 sig_t action;
1263
1264 mtx_lock(&ps->ps_mtx);
1265 action = ps->ps_sigact[_SIG_IDX(sig)];
1266 mtx_unlock(&ps->ps_mtx);
1267 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1268 }
1269 #endif
1270 if (sig == SIGKILL)
1271 sigexit(td, sig);
1272 }
1273 PROC_UNLOCK(p);
1274 return (error);
1275 }
1276
1277 #ifndef _SYS_SYSPROTO_H_
1278 struct sigpending_args {
1279 sigset_t *set;
1280 };
1281 #endif
1282 int
sys_sigpending(td,uap)1283 sys_sigpending(td, uap)
1284 struct thread *td;
1285 struct sigpending_args *uap;
1286 {
1287 struct proc *p = td->td_proc;
1288 sigset_t pending;
1289
1290 PROC_LOCK(p);
1291 pending = p->p_sigqueue.sq_signals;
1292 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1293 PROC_UNLOCK(p);
1294 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1295 }
1296
1297 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1298 #ifndef _SYS_SYSPROTO_H_
1299 struct osigpending_args {
1300 int dummy;
1301 };
1302 #endif
1303 int
osigpending(td,uap)1304 osigpending(td, uap)
1305 struct thread *td;
1306 struct osigpending_args *uap;
1307 {
1308 struct proc *p = td->td_proc;
1309 sigset_t pending;
1310
1311 PROC_LOCK(p);
1312 pending = p->p_sigqueue.sq_signals;
1313 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1314 PROC_UNLOCK(p);
1315 SIG2OSIG(pending, td->td_retval[0]);
1316 return (0);
1317 }
1318 #endif /* COMPAT_43 */
1319
1320 #if defined(COMPAT_43)
1321 /*
1322 * Generalized interface signal handler, 4.3-compatible.
1323 */
1324 #ifndef _SYS_SYSPROTO_H_
1325 struct osigvec_args {
1326 int signum;
1327 struct sigvec *nsv;
1328 struct sigvec *osv;
1329 };
1330 #endif
1331 /* ARGSUSED */
1332 int
osigvec(td,uap)1333 osigvec(td, uap)
1334 struct thread *td;
1335 register struct osigvec_args *uap;
1336 {
1337 struct sigvec vec;
1338 struct sigaction nsa, osa;
1339 register struct sigaction *nsap, *osap;
1340 int error;
1341
1342 if (uap->signum <= 0 || uap->signum >= ONSIG)
1343 return (EINVAL);
1344 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1345 osap = (uap->osv != NULL) ? &osa : NULL;
1346 if (nsap) {
1347 error = copyin(uap->nsv, &vec, sizeof(vec));
1348 if (error)
1349 return (error);
1350 nsap->sa_handler = vec.sv_handler;
1351 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1352 nsap->sa_flags = vec.sv_flags;
1353 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1354 }
1355 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1356 if (osap && !error) {
1357 vec.sv_handler = osap->sa_handler;
1358 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1359 vec.sv_flags = osap->sa_flags;
1360 vec.sv_flags &= ~SA_NOCLDWAIT;
1361 vec.sv_flags ^= SA_RESTART;
1362 error = copyout(&vec, uap->osv, sizeof(vec));
1363 }
1364 return (error);
1365 }
1366
1367 #ifndef _SYS_SYSPROTO_H_
1368 struct osigblock_args {
1369 int mask;
1370 };
1371 #endif
1372 int
osigblock(td,uap)1373 osigblock(td, uap)
1374 register struct thread *td;
1375 struct osigblock_args *uap;
1376 {
1377 sigset_t set, oset;
1378
1379 OSIG2SIG(uap->mask, set);
1380 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1381 SIG2OSIG(oset, td->td_retval[0]);
1382 return (0);
1383 }
1384
1385 #ifndef _SYS_SYSPROTO_H_
1386 struct osigsetmask_args {
1387 int mask;
1388 };
1389 #endif
1390 int
osigsetmask(td,uap)1391 osigsetmask(td, uap)
1392 struct thread *td;
1393 struct osigsetmask_args *uap;
1394 {
1395 sigset_t set, oset;
1396
1397 OSIG2SIG(uap->mask, set);
1398 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1399 SIG2OSIG(oset, td->td_retval[0]);
1400 return (0);
1401 }
1402 #endif /* COMPAT_43 */
1403
1404 /*
1405 * Suspend calling thread until signal, providing mask to be set in the
1406 * meantime.
1407 */
1408 #ifndef _SYS_SYSPROTO_H_
1409 struct sigsuspend_args {
1410 const sigset_t *sigmask;
1411 };
1412 #endif
1413 /* ARGSUSED */
1414 int
sys_sigsuspend(td,uap)1415 sys_sigsuspend(td, uap)
1416 struct thread *td;
1417 struct sigsuspend_args *uap;
1418 {
1419 sigset_t mask;
1420 int error;
1421
1422 error = copyin(uap->sigmask, &mask, sizeof(mask));
1423 if (error)
1424 return (error);
1425 return (kern_sigsuspend(td, mask));
1426 }
1427
1428 int
kern_sigsuspend(struct thread * td,sigset_t mask)1429 kern_sigsuspend(struct thread *td, sigset_t mask)
1430 {
1431 struct proc *p = td->td_proc;
1432 int has_sig, sig;
1433
1434 /*
1435 * When returning from sigsuspend, we want
1436 * the old mask to be restored after the
1437 * signal handler has finished. Thus, we
1438 * save it here and mark the sigacts structure
1439 * to indicate this.
1440 */
1441 PROC_LOCK(p);
1442 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1443 SIGPROCMASK_PROC_LOCKED);
1444 td->td_pflags |= TDP_OLDMASK;
1445
1446 /*
1447 * Process signals now. Otherwise, we can get spurious wakeup
1448 * due to signal entered process queue, but delivered to other
1449 * thread. But sigsuspend should return only on signal
1450 * delivery.
1451 */
1452 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1453 for (has_sig = 0; !has_sig;) {
1454 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1455 0) == 0)
1456 /* void */;
1457 thread_suspend_check(0);
1458 mtx_lock(&p->p_sigacts->ps_mtx);
1459 while ((sig = cursig(td, SIG_STOP_ALLOWED)) != 0)
1460 has_sig += postsig(sig);
1461 mtx_unlock(&p->p_sigacts->ps_mtx);
1462 }
1463 PROC_UNLOCK(p);
1464 td->td_errno = EINTR;
1465 td->td_pflags |= TDP_NERRNO;
1466 return (EJUSTRETURN);
1467 }
1468
1469 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1470 /*
1471 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1472 * convention: libc stub passes mask, not pointer, to save a copyin.
1473 */
1474 #ifndef _SYS_SYSPROTO_H_
1475 struct osigsuspend_args {
1476 osigset_t mask;
1477 };
1478 #endif
1479 /* ARGSUSED */
1480 int
osigsuspend(td,uap)1481 osigsuspend(td, uap)
1482 struct thread *td;
1483 struct osigsuspend_args *uap;
1484 {
1485 sigset_t mask;
1486
1487 OSIG2SIG(uap->mask, mask);
1488 return (kern_sigsuspend(td, mask));
1489 }
1490 #endif /* COMPAT_43 */
1491
1492 #if defined(COMPAT_43)
1493 #ifndef _SYS_SYSPROTO_H_
1494 struct osigstack_args {
1495 struct sigstack *nss;
1496 struct sigstack *oss;
1497 };
1498 #endif
1499 /* ARGSUSED */
1500 int
osigstack(td,uap)1501 osigstack(td, uap)
1502 struct thread *td;
1503 register struct osigstack_args *uap;
1504 {
1505 struct sigstack nss, oss;
1506 int error = 0;
1507
1508 if (uap->nss != NULL) {
1509 error = copyin(uap->nss, &nss, sizeof(nss));
1510 if (error)
1511 return (error);
1512 }
1513 oss.ss_sp = td->td_sigstk.ss_sp;
1514 oss.ss_onstack = sigonstack(cpu_getstack(td));
1515 if (uap->nss != NULL) {
1516 td->td_sigstk.ss_sp = nss.ss_sp;
1517 td->td_sigstk.ss_size = 0;
1518 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1519 td->td_pflags |= TDP_ALTSTACK;
1520 }
1521 if (uap->oss != NULL)
1522 error = copyout(&oss, uap->oss, sizeof(oss));
1523
1524 return (error);
1525 }
1526 #endif /* COMPAT_43 */
1527
1528 #ifndef _SYS_SYSPROTO_H_
1529 struct sigaltstack_args {
1530 stack_t *ss;
1531 stack_t *oss;
1532 };
1533 #endif
1534 /* ARGSUSED */
1535 int
sys_sigaltstack(td,uap)1536 sys_sigaltstack(td, uap)
1537 struct thread *td;
1538 register struct sigaltstack_args *uap;
1539 {
1540 stack_t ss, oss;
1541 int error;
1542
1543 if (uap->ss != NULL) {
1544 error = copyin(uap->ss, &ss, sizeof(ss));
1545 if (error)
1546 return (error);
1547 }
1548 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1549 (uap->oss != NULL) ? &oss : NULL);
1550 if (error)
1551 return (error);
1552 if (uap->oss != NULL)
1553 error = copyout(&oss, uap->oss, sizeof(stack_t));
1554 return (error);
1555 }
1556
1557 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1558 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1559 {
1560 struct proc *p = td->td_proc;
1561 int oonstack;
1562
1563 oonstack = sigonstack(cpu_getstack(td));
1564
1565 if (oss != NULL) {
1566 *oss = td->td_sigstk;
1567 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1568 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1569 }
1570
1571 if (ss != NULL) {
1572 if (oonstack)
1573 return (EPERM);
1574 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1575 return (EINVAL);
1576 if (!(ss->ss_flags & SS_DISABLE)) {
1577 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1578 return (ENOMEM);
1579
1580 td->td_sigstk = *ss;
1581 td->td_pflags |= TDP_ALTSTACK;
1582 } else {
1583 td->td_pflags &= ~TDP_ALTSTACK;
1584 }
1585 }
1586 return (0);
1587 }
1588
1589 /*
1590 * Common code for kill process group/broadcast kill.
1591 * cp is calling process.
1592 */
1593 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1594 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1595 {
1596 struct proc *p;
1597 struct pgrp *pgrp;
1598 int err;
1599 int ret;
1600
1601 ret = ESRCH;
1602 if (all) {
1603 /*
1604 * broadcast
1605 */
1606 sx_slock(&allproc_lock);
1607 FOREACH_PROC_IN_SYSTEM(p) {
1608 PROC_LOCK(p);
1609 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1610 p == td->td_proc || p->p_state == PRS_NEW) {
1611 PROC_UNLOCK(p);
1612 continue;
1613 }
1614 err = p_cansignal(td, p, sig);
1615 if (err == 0) {
1616 if (sig)
1617 pksignal(p, sig, ksi);
1618 ret = err;
1619 }
1620 else if (ret == ESRCH)
1621 ret = err;
1622 PROC_UNLOCK(p);
1623 }
1624 sx_sunlock(&allproc_lock);
1625 } else {
1626 sx_slock(&proctree_lock);
1627 if (pgid == 0) {
1628 /*
1629 * zero pgid means send to my process group.
1630 */
1631 pgrp = td->td_proc->p_pgrp;
1632 PGRP_LOCK(pgrp);
1633 } else {
1634 pgrp = pgfind(pgid);
1635 if (pgrp == NULL) {
1636 sx_sunlock(&proctree_lock);
1637 return (ESRCH);
1638 }
1639 }
1640 sx_sunlock(&proctree_lock);
1641 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1642 PROC_LOCK(p);
1643 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
1644 p->p_state == PRS_NEW) {
1645 PROC_UNLOCK(p);
1646 continue;
1647 }
1648 err = p_cansignal(td, p, sig);
1649 if (err == 0) {
1650 if (sig)
1651 pksignal(p, sig, ksi);
1652 ret = err;
1653 }
1654 else if (ret == ESRCH)
1655 ret = err;
1656 PROC_UNLOCK(p);
1657 }
1658 PGRP_UNLOCK(pgrp);
1659 }
1660 return (ret);
1661 }
1662
1663 #ifndef _SYS_SYSPROTO_H_
1664 struct kill_args {
1665 int pid;
1666 int signum;
1667 };
1668 #endif
1669 /* ARGSUSED */
1670 int
sys_kill(struct thread * td,struct kill_args * uap)1671 sys_kill(struct thread *td, struct kill_args *uap)
1672 {
1673 ksiginfo_t ksi;
1674 struct proc *p;
1675 int error;
1676
1677 AUDIT_ARG_SIGNUM(uap->signum);
1678 AUDIT_ARG_PID(uap->pid);
1679 if ((u_int)uap->signum > _SIG_MAXSIG)
1680 return (EINVAL);
1681
1682 ksiginfo_init(&ksi);
1683 ksi.ksi_signo = uap->signum;
1684 ksi.ksi_code = SI_USER;
1685 ksi.ksi_pid = td->td_proc->p_pid;
1686 ksi.ksi_uid = td->td_ucred->cr_ruid;
1687
1688 if (uap->pid > 0) {
1689 /* kill single process */
1690 if ((p = pfind(uap->pid)) == NULL) {
1691 if ((p = zpfind(uap->pid)) == NULL)
1692 return (ESRCH);
1693 }
1694 AUDIT_ARG_PROCESS(p);
1695 error = p_cansignal(td, p, uap->signum);
1696 if (error == 0 && uap->signum)
1697 pksignal(p, uap->signum, &ksi);
1698 PROC_UNLOCK(p);
1699 return (error);
1700 }
1701 switch (uap->pid) {
1702 case -1: /* broadcast signal */
1703 return (killpg1(td, uap->signum, 0, 1, &ksi));
1704 case 0: /* signal own process group */
1705 return (killpg1(td, uap->signum, 0, 0, &ksi));
1706 default: /* negative explicit process group */
1707 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
1708 }
1709 /* NOTREACHED */
1710 }
1711
1712 int
sys_pdkill(td,uap)1713 sys_pdkill(td, uap)
1714 struct thread *td;
1715 struct pdkill_args *uap;
1716 {
1717 #ifdef PROCDESC
1718 struct proc *p;
1719 int error;
1720
1721 AUDIT_ARG_SIGNUM(uap->signum);
1722 AUDIT_ARG_FD(uap->fd);
1723 if ((u_int)uap->signum > _SIG_MAXSIG)
1724 return (EINVAL);
1725
1726 error = procdesc_find(td, uap->fd, CAP_PDKILL, &p);
1727 if (error)
1728 return (error);
1729 AUDIT_ARG_PROCESS(p);
1730 error = p_cansignal(td, p, uap->signum);
1731 if (error == 0 && uap->signum)
1732 kern_psignal(p, uap->signum);
1733 PROC_UNLOCK(p);
1734 return (error);
1735 #else
1736 return (ENOSYS);
1737 #endif
1738 }
1739
1740 #if defined(COMPAT_43)
1741 #ifndef _SYS_SYSPROTO_H_
1742 struct okillpg_args {
1743 int pgid;
1744 int signum;
1745 };
1746 #endif
1747 /* ARGSUSED */
1748 int
okillpg(struct thread * td,struct okillpg_args * uap)1749 okillpg(struct thread *td, struct okillpg_args *uap)
1750 {
1751 ksiginfo_t ksi;
1752
1753 AUDIT_ARG_SIGNUM(uap->signum);
1754 AUDIT_ARG_PID(uap->pgid);
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 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
1764 }
1765 #endif /* COMPAT_43 */
1766
1767 #ifndef _SYS_SYSPROTO_H_
1768 struct sigqueue_args {
1769 pid_t pid;
1770 int signum;
1771 /* union sigval */ void *value;
1772 };
1773 #endif
1774 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)1775 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
1776 {
1777 ksiginfo_t ksi;
1778 struct proc *p;
1779 int error;
1780
1781 if ((u_int)uap->signum > _SIG_MAXSIG)
1782 return (EINVAL);
1783
1784 /*
1785 * Specification says sigqueue can only send signal to
1786 * single process.
1787 */
1788 if (uap->pid <= 0)
1789 return (EINVAL);
1790
1791 if ((p = pfind(uap->pid)) == NULL) {
1792 if ((p = zpfind(uap->pid)) == NULL)
1793 return (ESRCH);
1794 }
1795 error = p_cansignal(td, p, uap->signum);
1796 if (error == 0 && uap->signum != 0) {
1797 ksiginfo_init(&ksi);
1798 ksi.ksi_flags = KSI_SIGQ;
1799 ksi.ksi_signo = uap->signum;
1800 ksi.ksi_code = SI_QUEUE;
1801 ksi.ksi_pid = td->td_proc->p_pid;
1802 ksi.ksi_uid = td->td_ucred->cr_ruid;
1803 ksi.ksi_value.sival_ptr = uap->value;
1804 error = pksignal(p, ksi.ksi_signo, &ksi);
1805 }
1806 PROC_UNLOCK(p);
1807 return (error);
1808 }
1809
1810 /*
1811 * Send a signal to a process group.
1812 */
1813 void
gsignal(int pgid,int sig,ksiginfo_t * ksi)1814 gsignal(int pgid, int sig, ksiginfo_t *ksi)
1815 {
1816 struct pgrp *pgrp;
1817
1818 if (pgid != 0) {
1819 sx_slock(&proctree_lock);
1820 pgrp = pgfind(pgid);
1821 sx_sunlock(&proctree_lock);
1822 if (pgrp != NULL) {
1823 pgsignal(pgrp, sig, 0, ksi);
1824 PGRP_UNLOCK(pgrp);
1825 }
1826 }
1827 }
1828
1829 /*
1830 * Send a signal to a process group. If checktty is 1,
1831 * limit to members which have a controlling terminal.
1832 */
1833 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)1834 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
1835 {
1836 struct proc *p;
1837
1838 if (pgrp) {
1839 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
1840 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1841 PROC_LOCK(p);
1842 if (p->p_state == PRS_NORMAL &&
1843 (checkctty == 0 || p->p_flag & P_CONTROLT))
1844 pksignal(p, sig, ksi);
1845 PROC_UNLOCK(p);
1846 }
1847 }
1848 }
1849
1850
1851 /*
1852 * Recalculate the signal mask and reset the signal disposition after
1853 * usermode frame for delivery is formed. Should be called after
1854 * mach-specific routine, because sysent->sv_sendsig() needs correct
1855 * ps_siginfo and signal mask.
1856 */
1857 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)1858 postsig_done(int sig, struct thread *td, struct sigacts *ps)
1859 {
1860 sigset_t mask;
1861
1862 mtx_assert(&ps->ps_mtx, MA_OWNED);
1863 td->td_ru.ru_nsignals++;
1864 mask = ps->ps_catchmask[_SIG_IDX(sig)];
1865 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1866 SIGADDSET(mask, sig);
1867 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
1868 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
1869 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1870 SIGDELSET(ps->ps_sigcatch, sig);
1871 if (sig != SIGCONT &&
1872 sigprop(sig) & SA_IGNORE)
1873 SIGADDSET(ps->ps_sigignore, sig);
1874 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1875 }
1876 }
1877
1878 /*
1879 * Send a signal caused by a trap to the current thread. If it will be
1880 * caught immediately, deliver it with correct code. Otherwise, post it
1881 * normally.
1882 */
1883 void
trapsignal(struct thread * td,ksiginfo_t * ksi)1884 trapsignal(struct thread *td, ksiginfo_t *ksi)
1885 {
1886 struct sigacts *ps;
1887 struct proc *p;
1888 int sig;
1889 int code;
1890
1891 p = td->td_proc;
1892 sig = ksi->ksi_signo;
1893 code = ksi->ksi_code;
1894 KASSERT(_SIG_VALID(sig), ("invalid signal"));
1895
1896 PROC_LOCK(p);
1897 ps = p->p_sigacts;
1898 mtx_lock(&ps->ps_mtx);
1899 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
1900 !SIGISMEMBER(td->td_sigmask, sig)) {
1901 #ifdef KTRACE
1902 if (KTRPOINT(curthread, KTR_PSIG))
1903 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
1904 &td->td_sigmask, code);
1905 #endif
1906 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
1907 ksi, &td->td_sigmask);
1908 postsig_done(sig, td, ps);
1909 mtx_unlock(&ps->ps_mtx);
1910 } else {
1911 /*
1912 * Avoid a possible infinite loop if the thread
1913 * masking the signal or process is ignoring the
1914 * signal.
1915 */
1916 if (kern_forcesigexit &&
1917 (SIGISMEMBER(td->td_sigmask, sig) ||
1918 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
1919 SIGDELSET(td->td_sigmask, sig);
1920 SIGDELSET(ps->ps_sigcatch, sig);
1921 SIGDELSET(ps->ps_sigignore, sig);
1922 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1923 }
1924 mtx_unlock(&ps->ps_mtx);
1925 p->p_code = code; /* XXX for core dump/debugger */
1926 p->p_sig = sig; /* XXX to verify code */
1927 tdsendsignal(p, td, sig, ksi);
1928 }
1929 PROC_UNLOCK(p);
1930 }
1931
1932 static struct thread *
sigtd(struct proc * p,int sig,int prop)1933 sigtd(struct proc *p, int sig, int prop)
1934 {
1935 struct thread *td, *signal_td;
1936
1937 PROC_LOCK_ASSERT(p, MA_OWNED);
1938
1939 /*
1940 * Check if current thread can handle the signal without
1941 * switching context to another thread.
1942 */
1943 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
1944 return (curthread);
1945 signal_td = NULL;
1946 FOREACH_THREAD_IN_PROC(p, td) {
1947 if (!SIGISMEMBER(td->td_sigmask, sig)) {
1948 signal_td = td;
1949 break;
1950 }
1951 }
1952 if (signal_td == NULL)
1953 signal_td = FIRST_THREAD_IN_PROC(p);
1954 return (signal_td);
1955 }
1956
1957 /*
1958 * Send the signal to the process. If the signal has an action, the action
1959 * is usually performed by the target process rather than the caller; we add
1960 * the signal to the set of pending signals for the process.
1961 *
1962 * Exceptions:
1963 * o When a stop signal is sent to a sleeping process that takes the
1964 * default action, the process is stopped without awakening it.
1965 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1966 * regardless of the signal action (eg, blocked or ignored).
1967 *
1968 * Other ignored signals are discarded immediately.
1969 *
1970 * NB: This function may be entered from the debugger via the "kill" DDB
1971 * command. There is little that can be done to mitigate the possibly messy
1972 * side effects of this unwise possibility.
1973 */
1974 void
kern_psignal(struct proc * p,int sig)1975 kern_psignal(struct proc *p, int sig)
1976 {
1977 ksiginfo_t ksi;
1978
1979 ksiginfo_init(&ksi);
1980 ksi.ksi_signo = sig;
1981 ksi.ksi_code = SI_KERNEL;
1982 (void) tdsendsignal(p, NULL, sig, &ksi);
1983 }
1984
1985 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)1986 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
1987 {
1988
1989 return (tdsendsignal(p, NULL, sig, ksi));
1990 }
1991
1992 /* Utility function for finding a thread to send signal event to. */
1993 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)1994 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
1995 {
1996 struct thread *td;
1997
1998 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
1999 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2000 if (td == NULL)
2001 return (ESRCH);
2002 *ttd = td;
2003 } else {
2004 *ttd = NULL;
2005 PROC_LOCK(p);
2006 }
2007 return (0);
2008 }
2009
2010 void
tdsignal(struct thread * td,int sig)2011 tdsignal(struct thread *td, int sig)
2012 {
2013 ksiginfo_t ksi;
2014
2015 ksiginfo_init(&ksi);
2016 ksi.ksi_signo = sig;
2017 ksi.ksi_code = SI_KERNEL;
2018 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2019 }
2020
2021 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2022 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2023 {
2024
2025 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2026 }
2027
2028 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2029 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2030 {
2031 sig_t action;
2032 sigqueue_t *sigqueue;
2033 int prop;
2034 struct sigacts *ps;
2035 int intrval;
2036 int ret = 0;
2037 int wakeup_swapper;
2038
2039 MPASS(td == NULL || p == td->td_proc);
2040 PROC_LOCK_ASSERT(p, MA_OWNED);
2041
2042 if (!_SIG_VALID(sig))
2043 panic("%s(): invalid signal %d", __func__, sig);
2044
2045 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2046
2047 /*
2048 * IEEE Std 1003.1-2001: return success when killing a zombie.
2049 */
2050 if (p->p_state == PRS_ZOMBIE) {
2051 if (ksi && (ksi->ksi_flags & KSI_INS))
2052 ksiginfo_tryfree(ksi);
2053 return (ret);
2054 }
2055
2056 ps = p->p_sigacts;
2057 KNOTE_LOCKED(&p->p_klist, NOTE_SIGNAL | sig);
2058 prop = sigprop(sig);
2059
2060 if (td == NULL) {
2061 td = sigtd(p, sig, prop);
2062 sigqueue = &p->p_sigqueue;
2063 } else {
2064 KASSERT(td->td_proc == p, ("invalid thread"));
2065 sigqueue = &td->td_sigqueue;
2066 }
2067
2068 SDT_PROBE3(proc, kernel, , signal__send, td, p, sig);
2069
2070 /*
2071 * If the signal is being ignored,
2072 * then we forget about it immediately.
2073 * (Note: we don't set SIGCONT in ps_sigignore,
2074 * and if it is set to SIG_IGN,
2075 * action will be SIG_DFL here.)
2076 */
2077 mtx_lock(&ps->ps_mtx);
2078 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2079 SDT_PROBE3(proc, kernel, , signal__discard, td, p, sig);
2080
2081 mtx_unlock(&ps->ps_mtx);
2082 if (ksi && (ksi->ksi_flags & KSI_INS))
2083 ksiginfo_tryfree(ksi);
2084 return (ret);
2085 }
2086 if (SIGISMEMBER(td->td_sigmask, sig))
2087 action = SIG_HOLD;
2088 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2089 action = SIG_CATCH;
2090 else
2091 action = SIG_DFL;
2092 if (SIGISMEMBER(ps->ps_sigintr, sig))
2093 intrval = EINTR;
2094 else
2095 intrval = ERESTART;
2096 mtx_unlock(&ps->ps_mtx);
2097
2098 if (prop & SA_CONT)
2099 sigqueue_delete_stopmask_proc(p);
2100 else if (prop & SA_STOP) {
2101 /*
2102 * If sending a tty stop signal to a member of an orphaned
2103 * process group, discard the signal here if the action
2104 * is default; don't stop the process below if sleeping,
2105 * and don't clear any pending SIGCONT.
2106 */
2107 if ((prop & SA_TTYSTOP) &&
2108 (p->p_pgrp->pg_jobc == 0) &&
2109 (action == SIG_DFL)) {
2110 if (ksi && (ksi->ksi_flags & KSI_INS))
2111 ksiginfo_tryfree(ksi);
2112 return (ret);
2113 }
2114 sigqueue_delete_proc(p, SIGCONT);
2115 if (p->p_flag & P_CONTINUED) {
2116 p->p_flag &= ~P_CONTINUED;
2117 PROC_LOCK(p->p_pptr);
2118 sigqueue_take(p->p_ksi);
2119 PROC_UNLOCK(p->p_pptr);
2120 }
2121 }
2122
2123 ret = sigqueue_add(sigqueue, sig, ksi);
2124 if (ret != 0)
2125 return (ret);
2126 signotify(td);
2127 /*
2128 * Defer further processing for signals which are held,
2129 * except that stopped processes must be continued by SIGCONT.
2130 */
2131 if (action == SIG_HOLD &&
2132 !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
2133 return (ret);
2134 /*
2135 * SIGKILL: Remove procfs STOPEVENTs.
2136 */
2137 if (sig == SIGKILL) {
2138 /* from procfs_ioctl.c: PIOCBIC */
2139 p->p_stops = 0;
2140 /* from procfs_ioctl.c: PIOCCONT */
2141 p->p_step = 0;
2142 wakeup(&p->p_step);
2143 }
2144 /*
2145 * Some signals have a process-wide effect and a per-thread
2146 * component. Most processing occurs when the process next
2147 * tries to cross the user boundary, however there are some
2148 * times when processing needs to be done immediatly, such as
2149 * waking up threads so that they can cross the user boundary.
2150 * We try do the per-process part here.
2151 */
2152 if (P_SHOULDSTOP(p)) {
2153 KASSERT(!(p->p_flag & P_WEXIT),
2154 ("signal to stopped but exiting process"));
2155 if (sig == SIGKILL) {
2156 /*
2157 * If traced process is already stopped,
2158 * then no further action is necessary.
2159 */
2160 if (p->p_flag & P_TRACED)
2161 goto out;
2162 /*
2163 * SIGKILL sets process running.
2164 * It will die elsewhere.
2165 * All threads must be restarted.
2166 */
2167 p->p_flag &= ~P_STOPPED_SIG;
2168 goto runfast;
2169 }
2170
2171 if (prop & SA_CONT) {
2172 /*
2173 * If traced process is already stopped,
2174 * then no further action is necessary.
2175 */
2176 if (p->p_flag & P_TRACED)
2177 goto out;
2178 /*
2179 * If SIGCONT is default (or ignored), we continue the
2180 * process but don't leave the signal in sigqueue as
2181 * it has no further action. If SIGCONT is held, we
2182 * continue the process and leave the signal in
2183 * sigqueue. If the process catches SIGCONT, let it
2184 * handle the signal itself. If it isn't waiting on
2185 * an event, it goes back to run state.
2186 * Otherwise, process goes back to sleep state.
2187 */
2188 p->p_flag &= ~P_STOPPED_SIG;
2189 PROC_SLOCK(p);
2190 if (p->p_numthreads == p->p_suspcount) {
2191 PROC_SUNLOCK(p);
2192 p->p_flag |= P_CONTINUED;
2193 p->p_xstat = SIGCONT;
2194 PROC_LOCK(p->p_pptr);
2195 childproc_continued(p);
2196 PROC_UNLOCK(p->p_pptr);
2197 PROC_SLOCK(p);
2198 }
2199 if (action == SIG_DFL) {
2200 thread_unsuspend(p);
2201 PROC_SUNLOCK(p);
2202 sigqueue_delete(sigqueue, sig);
2203 goto out;
2204 }
2205 if (action == SIG_CATCH) {
2206 /*
2207 * The process wants to catch it so it needs
2208 * to run at least one thread, but which one?
2209 */
2210 PROC_SUNLOCK(p);
2211 goto runfast;
2212 }
2213 /*
2214 * The signal is not ignored or caught.
2215 */
2216 thread_unsuspend(p);
2217 PROC_SUNLOCK(p);
2218 goto out;
2219 }
2220
2221 if (prop & SA_STOP) {
2222 /*
2223 * If traced process is already stopped,
2224 * then no further action is necessary.
2225 */
2226 if (p->p_flag & P_TRACED)
2227 goto out;
2228 /*
2229 * Already stopped, don't need to stop again
2230 * (If we did the shell could get confused).
2231 * Just make sure the signal STOP bit set.
2232 */
2233 p->p_flag |= P_STOPPED_SIG;
2234 sigqueue_delete(sigqueue, sig);
2235 goto out;
2236 }
2237
2238 /*
2239 * All other kinds of signals:
2240 * If a thread is sleeping interruptibly, simulate a
2241 * wakeup so that when it is continued it will be made
2242 * runnable and can look at the signal. However, don't make
2243 * the PROCESS runnable, leave it stopped.
2244 * It may run a bit until it hits a thread_suspend_check().
2245 */
2246 wakeup_swapper = 0;
2247 PROC_SLOCK(p);
2248 thread_lock(td);
2249 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
2250 wakeup_swapper = sleepq_abort(td, intrval);
2251 thread_unlock(td);
2252 PROC_SUNLOCK(p);
2253 if (wakeup_swapper)
2254 kick_proc0();
2255 goto out;
2256 /*
2257 * Mutexes are short lived. Threads waiting on them will
2258 * hit thread_suspend_check() soon.
2259 */
2260 } else if (p->p_state == PRS_NORMAL) {
2261 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2262 tdsigwakeup(td, sig, action, intrval);
2263 goto out;
2264 }
2265
2266 MPASS(action == SIG_DFL);
2267
2268 if (prop & SA_STOP) {
2269 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2270 goto out;
2271 p->p_flag |= P_STOPPED_SIG;
2272 p->p_xstat = sig;
2273 PROC_SLOCK(p);
2274 sig_suspend_threads(td, p, 1);
2275 if (p->p_numthreads == p->p_suspcount) {
2276 /*
2277 * only thread sending signal to another
2278 * process can reach here, if thread is sending
2279 * signal to its process, because thread does
2280 * not suspend itself here, p_numthreads
2281 * should never be equal to p_suspcount.
2282 */
2283 thread_stopped(p);
2284 PROC_SUNLOCK(p);
2285 sigqueue_delete_proc(p, p->p_xstat);
2286 } else
2287 PROC_SUNLOCK(p);
2288 goto out;
2289 }
2290 } else {
2291 /* Not in "NORMAL" state. discard the signal. */
2292 sigqueue_delete(sigqueue, sig);
2293 goto out;
2294 }
2295
2296 /*
2297 * The process is not stopped so we need to apply the signal to all the
2298 * running threads.
2299 */
2300 runfast:
2301 tdsigwakeup(td, sig, action, intrval);
2302 PROC_SLOCK(p);
2303 thread_unsuspend(p);
2304 PROC_SUNLOCK(p);
2305 out:
2306 /* If we jump here, proc slock should not be owned. */
2307 PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
2308 return (ret);
2309 }
2310
2311 /*
2312 * The force of a signal has been directed against a single
2313 * thread. We need to see what we can do about knocking it
2314 * out of any sleep it may be in etc.
2315 */
2316 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2317 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2318 {
2319 struct proc *p = td->td_proc;
2320 register int prop;
2321 int wakeup_swapper;
2322
2323 wakeup_swapper = 0;
2324 PROC_LOCK_ASSERT(p, MA_OWNED);
2325 prop = sigprop(sig);
2326
2327 PROC_SLOCK(p);
2328 thread_lock(td);
2329 /*
2330 * Bring the priority of a thread up if we want it to get
2331 * killed in this lifetime.
2332 */
2333 if (action == SIG_DFL && (prop & SA_KILL) && td->td_priority > PUSER)
2334 sched_prio(td, PUSER);
2335 if (TD_ON_SLEEPQ(td)) {
2336 /*
2337 * If thread is sleeping uninterruptibly
2338 * we can't interrupt the sleep... the signal will
2339 * be noticed when the process returns through
2340 * trap() or syscall().
2341 */
2342 if ((td->td_flags & TDF_SINTR) == 0)
2343 goto out;
2344 /*
2345 * If SIGCONT is default (or ignored) and process is
2346 * asleep, we are finished; the process should not
2347 * be awakened.
2348 */
2349 if ((prop & SA_CONT) && action == SIG_DFL) {
2350 thread_unlock(td);
2351 PROC_SUNLOCK(p);
2352 sigqueue_delete(&p->p_sigqueue, sig);
2353 /*
2354 * It may be on either list in this state.
2355 * Remove from both for now.
2356 */
2357 sigqueue_delete(&td->td_sigqueue, sig);
2358 return;
2359 }
2360
2361 /*
2362 * Don't awaken a sleeping thread for SIGSTOP if the
2363 * STOP signal is deferred.
2364 */
2365 if ((prop & SA_STOP) && (td->td_flags & TDF_SBDRY))
2366 goto out;
2367
2368 /*
2369 * Give low priority threads a better chance to run.
2370 */
2371 if (td->td_priority > PUSER)
2372 sched_prio(td, PUSER);
2373
2374 wakeup_swapper = sleepq_abort(td, intrval);
2375 } else {
2376 /*
2377 * Other states do nothing with the signal immediately,
2378 * other than kicking ourselves if we are running.
2379 * It will either never be noticed, or noticed very soon.
2380 */
2381 #ifdef SMP
2382 if (TD_IS_RUNNING(td) && td != curthread)
2383 forward_signal(td);
2384 #endif
2385 }
2386 out:
2387 PROC_SUNLOCK(p);
2388 thread_unlock(td);
2389 if (wakeup_swapper)
2390 kick_proc0();
2391 }
2392
2393 static void
sig_suspend_threads(struct thread * td,struct proc * p,int sending)2394 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
2395 {
2396 struct thread *td2;
2397 int wakeup_swapper;
2398
2399 PROC_LOCK_ASSERT(p, MA_OWNED);
2400 PROC_SLOCK_ASSERT(p, MA_OWNED);
2401
2402 wakeup_swapper = 0;
2403 FOREACH_THREAD_IN_PROC(p, td2) {
2404 thread_lock(td2);
2405 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
2406 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
2407 (td2->td_flags & TDF_SINTR)) {
2408 if (td2->td_flags & TDF_SBDRY) {
2409 /*
2410 * Once a thread is asleep with
2411 * TDF_SBDRY set, it should never
2412 * become suspended due to this check.
2413 */
2414 KASSERT(!TD_IS_SUSPENDED(td2),
2415 ("thread with deferred stops suspended"));
2416 } else if (!TD_IS_SUSPENDED(td2)) {
2417 thread_suspend_one(td2);
2418 }
2419 } else if (!TD_IS_SUSPENDED(td2)) {
2420 if (sending || td != td2)
2421 td2->td_flags |= TDF_ASTPENDING;
2422 #ifdef SMP
2423 if (TD_IS_RUNNING(td2) && td2 != td)
2424 forward_signal(td2);
2425 #endif
2426 }
2427 thread_unlock(td2);
2428 }
2429 if (wakeup_swapper)
2430 kick_proc0();
2431 }
2432
2433 int
ptracestop(struct thread * td,int sig)2434 ptracestop(struct thread *td, int sig)
2435 {
2436 struct proc *p = td->td_proc;
2437
2438 PROC_LOCK_ASSERT(p, MA_OWNED);
2439 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2440 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2441 &p->p_mtx.lock_object, "Stopping for traced signal");
2442
2443 td->td_dbgflags |= TDB_XSIG;
2444 td->td_xsig = sig;
2445 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2446 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2447 PROC_SLOCK(p);
2448 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2449 if (p->p_flag & P_SINGLE_EXIT) {
2450 td->td_dbgflags &= ~TDB_XSIG;
2451 PROC_SUNLOCK(p);
2452 return (sig);
2453 }
2454 /*
2455 * Just make wait() to work, the last stopped thread
2456 * will win.
2457 */
2458 p->p_xstat = sig;
2459 p->p_xthread = td;
2460 p->p_flag |= (P_STOPPED_SIG|P_STOPPED_TRACE);
2461 sig_suspend_threads(td, p, 0);
2462 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2463 td->td_dbgflags &= ~TDB_STOPATFORK;
2464 cv_broadcast(&p->p_dbgwait);
2465 }
2466 stopme:
2467 thread_suspend_switch(td);
2468 if (!(p->p_flag & P_TRACED)) {
2469 break;
2470 }
2471 if (td->td_dbgflags & TDB_SUSPEND) {
2472 if (p->p_flag & P_SINGLE_EXIT)
2473 break;
2474 goto stopme;
2475 }
2476 }
2477 PROC_SUNLOCK(p);
2478 return (td->td_xsig);
2479 }
2480
2481 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2482 reschedule_signals(struct proc *p, sigset_t block, int flags)
2483 {
2484 struct sigacts *ps;
2485 struct thread *td;
2486 int sig;
2487
2488 PROC_LOCK_ASSERT(p, MA_OWNED);
2489 if (SIGISEMPTY(p->p_siglist))
2490 return;
2491 ps = p->p_sigacts;
2492 SIGSETAND(block, p->p_siglist);
2493 while ((sig = sig_ffs(&block)) != 0) {
2494 SIGDELSET(block, sig);
2495 td = sigtd(p, sig, 0);
2496 signotify(td);
2497 if (!(flags & SIGPROCMASK_PS_LOCKED))
2498 mtx_lock(&ps->ps_mtx);
2499 if (p->p_flag & P_TRACED || SIGISMEMBER(ps->ps_sigcatch, sig))
2500 tdsigwakeup(td, sig, SIG_CATCH,
2501 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
2502 ERESTART));
2503 if (!(flags & SIGPROCMASK_PS_LOCKED))
2504 mtx_unlock(&ps->ps_mtx);
2505 }
2506 }
2507
2508 void
tdsigcleanup(struct thread * td)2509 tdsigcleanup(struct thread *td)
2510 {
2511 struct proc *p;
2512 sigset_t unblocked;
2513
2514 p = td->td_proc;
2515 PROC_LOCK_ASSERT(p, MA_OWNED);
2516
2517 sigqueue_flush(&td->td_sigqueue);
2518 if (p->p_numthreads == 1)
2519 return;
2520
2521 /*
2522 * Since we cannot handle signals, notify signal post code
2523 * about this by filling the sigmask.
2524 *
2525 * Also, if needed, wake up thread(s) that do not block the
2526 * same signals as the exiting thread, since the thread might
2527 * have been selected for delivery and woken up.
2528 */
2529 SIGFILLSET(unblocked);
2530 SIGSETNAND(unblocked, td->td_sigmask);
2531 SIGFILLSET(td->td_sigmask);
2532 reschedule_signals(p, unblocked, 0);
2533
2534 }
2535
2536 /*
2537 * Defer the delivery of SIGSTOP for the current thread. Returns true
2538 * if stops were deferred and false if they were already deferred.
2539 */
2540 int
sigdeferstop(void)2541 sigdeferstop(void)
2542 {
2543 struct thread *td;
2544
2545 td = curthread;
2546 if (td->td_flags & TDF_SBDRY)
2547 return (0);
2548 thread_lock(td);
2549 td->td_flags |= TDF_SBDRY;
2550 thread_unlock(td);
2551 return (1);
2552 }
2553
2554 /*
2555 * Permit the delivery of SIGSTOP for the current thread. This does
2556 * not immediately suspend if a stop was posted. Instead, the thread
2557 * will suspend either via ast() or a subsequent interruptible sleep.
2558 */
2559 void
sigallowstop()2560 sigallowstop()
2561 {
2562 struct thread *td;
2563
2564 td = curthread;
2565 thread_lock(td);
2566 td->td_flags &= ~TDF_SBDRY;
2567 thread_unlock(td);
2568 }
2569
2570 /*
2571 * If the current process has received a signal (should be caught or cause
2572 * termination, should interrupt current syscall), return the signal number.
2573 * Stop signals with default action are processed immediately, then cleared;
2574 * they aren't returned. This is checked after each entry to the system for
2575 * a syscall or trap (though this can usually be done without calling issignal
2576 * by checking the pending signal masks in cursig.) The normal call
2577 * sequence is
2578 *
2579 * while (sig = cursig(curthread))
2580 * postsig(sig);
2581 */
2582 static int
issignal(struct thread * td,int stop_allowed)2583 issignal(struct thread *td, int stop_allowed)
2584 {
2585 struct proc *p;
2586 struct sigacts *ps;
2587 struct sigqueue *queue;
2588 sigset_t sigpending;
2589 int sig, prop, newsig;
2590
2591 p = td->td_proc;
2592 ps = p->p_sigacts;
2593 mtx_assert(&ps->ps_mtx, MA_OWNED);
2594 PROC_LOCK_ASSERT(p, MA_OWNED);
2595 for (;;) {
2596 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
2597
2598 sigpending = td->td_sigqueue.sq_signals;
2599 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
2600 SIGSETNAND(sigpending, td->td_sigmask);
2601
2602 if (p->p_flag & P_PPWAIT || td->td_flags & TDF_SBDRY)
2603 SIG_STOPSIGMASK(sigpending);
2604 if (SIGISEMPTY(sigpending)) /* no signal to send */
2605 return (0);
2606 sig = sig_ffs(&sigpending);
2607
2608 if (p->p_stops & S_SIG) {
2609 mtx_unlock(&ps->ps_mtx);
2610 stopevent(p, S_SIG, sig);
2611 mtx_lock(&ps->ps_mtx);
2612 }
2613
2614 /*
2615 * We should see pending but ignored signals
2616 * only if P_TRACED was on when they were posted.
2617 */
2618 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
2619 sigqueue_delete(&td->td_sigqueue, sig);
2620 sigqueue_delete(&p->p_sigqueue, sig);
2621 continue;
2622 }
2623 if (p->p_flag & P_TRACED && (p->p_flag & P_PPTRACE) == 0) {
2624 /*
2625 * If traced, always stop.
2626 * Remove old signal from queue before the stop.
2627 * XXX shrug off debugger, it causes siginfo to
2628 * be thrown away.
2629 */
2630 queue = &td->td_sigqueue;
2631 td->td_dbgksi.ksi_signo = 0;
2632 if (sigqueue_get(queue, sig, &td->td_dbgksi) == 0) {
2633 queue = &p->p_sigqueue;
2634 sigqueue_get(queue, sig, &td->td_dbgksi);
2635 }
2636
2637 mtx_unlock(&ps->ps_mtx);
2638 newsig = ptracestop(td, sig);
2639 mtx_lock(&ps->ps_mtx);
2640
2641 if (sig != newsig) {
2642
2643 /*
2644 * If parent wants us to take the signal,
2645 * then it will leave it in p->p_xstat;
2646 * otherwise we just look for signals again.
2647 */
2648 if (newsig == 0)
2649 continue;
2650 sig = newsig;
2651
2652 /*
2653 * Put the new signal into td_sigqueue. If the
2654 * signal is being masked, look for other signals.
2655 */
2656 sigqueue_add(queue, sig, NULL);
2657 if (SIGISMEMBER(td->td_sigmask, sig))
2658 continue;
2659 signotify(td);
2660 } else {
2661 if (td->td_dbgksi.ksi_signo != 0) {
2662 td->td_dbgksi.ksi_flags |= KSI_HEAD;
2663 if (sigqueue_add(&td->td_sigqueue, sig,
2664 &td->td_dbgksi) != 0)
2665 td->td_dbgksi.ksi_signo = 0;
2666 }
2667 if (td->td_dbgksi.ksi_signo == 0)
2668 sigqueue_add(&td->td_sigqueue, sig,
2669 NULL);
2670 }
2671
2672 /*
2673 * If the traced bit got turned off, go back up
2674 * to the top to rescan signals. This ensures
2675 * that p_sig* and p_sigact are consistent.
2676 */
2677 if ((p->p_flag & P_TRACED) == 0)
2678 continue;
2679 }
2680
2681 prop = sigprop(sig);
2682
2683 /*
2684 * Decide whether the signal should be returned.
2685 * Return the signal's number, or fall through
2686 * to clear it from the pending mask.
2687 */
2688 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2689
2690 case (intptr_t)SIG_DFL:
2691 /*
2692 * Don't take default actions on system processes.
2693 */
2694 if (p->p_pid <= 1) {
2695 #ifdef DIAGNOSTIC
2696 /*
2697 * Are you sure you want to ignore SIGSEGV
2698 * in init? XXX
2699 */
2700 printf("Process (pid %lu) got signal %d\n",
2701 (u_long)p->p_pid, sig);
2702 #endif
2703 break; /* == ignore */
2704 }
2705 /*
2706 * If there is a pending stop signal to process
2707 * with default action, stop here,
2708 * then clear the signal. However,
2709 * if process is member of an orphaned
2710 * process group, ignore tty stop signals.
2711 */
2712 if (prop & SA_STOP) {
2713 if (p->p_flag & (P_TRACED|P_WEXIT) ||
2714 (p->p_pgrp->pg_jobc == 0 &&
2715 prop & SA_TTYSTOP))
2716 break; /* == ignore */
2717 mtx_unlock(&ps->ps_mtx);
2718 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2719 &p->p_mtx.lock_object, "Catching SIGSTOP");
2720 p->p_flag |= P_STOPPED_SIG;
2721 p->p_xstat = sig;
2722 PROC_SLOCK(p);
2723 sig_suspend_threads(td, p, 0);
2724 thread_suspend_switch(td);
2725 PROC_SUNLOCK(p);
2726 mtx_lock(&ps->ps_mtx);
2727 break;
2728 } else if (prop & SA_IGNORE) {
2729 /*
2730 * Except for SIGCONT, shouldn't get here.
2731 * Default action is to ignore; drop it.
2732 */
2733 break; /* == ignore */
2734 } else
2735 return (sig);
2736 /*NOTREACHED*/
2737
2738 case (intptr_t)SIG_IGN:
2739 /*
2740 * Masking above should prevent us ever trying
2741 * to take action on an ignored signal other
2742 * than SIGCONT, unless process is traced.
2743 */
2744 if ((prop & SA_CONT) == 0 &&
2745 (p->p_flag & P_TRACED) == 0)
2746 printf("issignal\n");
2747 break; /* == ignore */
2748
2749 default:
2750 /*
2751 * This signal has an action, let
2752 * postsig() process it.
2753 */
2754 return (sig);
2755 }
2756 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
2757 sigqueue_delete(&p->p_sigqueue, sig);
2758 }
2759 /* NOTREACHED */
2760 }
2761
2762 void
thread_stopped(struct proc * p)2763 thread_stopped(struct proc *p)
2764 {
2765 int n;
2766
2767 PROC_LOCK_ASSERT(p, MA_OWNED);
2768 PROC_SLOCK_ASSERT(p, MA_OWNED);
2769 n = p->p_suspcount;
2770 if (p == curproc)
2771 n++;
2772 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
2773 PROC_SUNLOCK(p);
2774 p->p_flag &= ~P_WAITED;
2775 PROC_LOCK(p->p_pptr);
2776 childproc_stopped(p, (p->p_flag & P_TRACED) ?
2777 CLD_TRAPPED : CLD_STOPPED);
2778 PROC_UNLOCK(p->p_pptr);
2779 PROC_SLOCK(p);
2780 }
2781 }
2782
2783 /*
2784 * Take the action for the specified signal
2785 * from the current set of pending signals.
2786 */
2787 int
postsig(sig)2788 postsig(sig)
2789 register int sig;
2790 {
2791 struct thread *td = curthread;
2792 register struct proc *p = td->td_proc;
2793 struct sigacts *ps;
2794 sig_t action;
2795 ksiginfo_t ksi;
2796 sigset_t returnmask;
2797
2798 KASSERT(sig != 0, ("postsig"));
2799
2800 PROC_LOCK_ASSERT(p, MA_OWNED);
2801 ps = p->p_sigacts;
2802 mtx_assert(&ps->ps_mtx, MA_OWNED);
2803 ksiginfo_init(&ksi);
2804 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
2805 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
2806 return (0);
2807 ksi.ksi_signo = sig;
2808 if (ksi.ksi_code == SI_TIMER)
2809 itimer_accept(p, ksi.ksi_timerid, &ksi);
2810 action = ps->ps_sigact[_SIG_IDX(sig)];
2811 #ifdef KTRACE
2812 if (KTRPOINT(td, KTR_PSIG))
2813 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
2814 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
2815 #endif
2816 if (p->p_stops & S_SIG) {
2817 mtx_unlock(&ps->ps_mtx);
2818 stopevent(p, S_SIG, sig);
2819 mtx_lock(&ps->ps_mtx);
2820 }
2821
2822 if (action == SIG_DFL) {
2823 /*
2824 * Default action, where the default is to kill
2825 * the process. (Other cases were ignored above.)
2826 */
2827 mtx_unlock(&ps->ps_mtx);
2828 sigexit(td, sig);
2829 /* NOTREACHED */
2830 } else {
2831 /*
2832 * If we get here, the signal must be caught.
2833 */
2834 KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
2835 ("postsig action"));
2836 /*
2837 * Set the new mask value and also defer further
2838 * occurrences of this signal.
2839 *
2840 * Special case: user has done a sigsuspend. Here the
2841 * current mask is not of interest, but rather the
2842 * mask from before the sigsuspend is what we want
2843 * restored after the signal processing is completed.
2844 */
2845 if (td->td_pflags & TDP_OLDMASK) {
2846 returnmask = td->td_oldsigmask;
2847 td->td_pflags &= ~TDP_OLDMASK;
2848 } else
2849 returnmask = td->td_sigmask;
2850
2851 if (p->p_sig == sig) {
2852 p->p_code = 0;
2853 p->p_sig = 0;
2854 }
2855 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
2856 postsig_done(sig, td, ps);
2857 }
2858 return (1);
2859 }
2860
2861 /*
2862 * Kill the current process for stated reason.
2863 */
2864 void
killproc(p,why)2865 killproc(p, why)
2866 struct proc *p;
2867 char *why;
2868 {
2869
2870 PROC_LOCK_ASSERT(p, MA_OWNED);
2871 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)",
2872 p, p->p_pid, p->p_comm);
2873 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
2874 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2875 p->p_flag |= P_WKILLED;
2876 kern_psignal(p, SIGKILL);
2877 }
2878
2879 /*
2880 * Force the current process to exit with the specified signal, dumping core
2881 * if appropriate. We bypass the normal tests for masked and caught signals,
2882 * allowing unrecoverable failures to terminate the process without changing
2883 * signal state. Mark the accounting record with the signal termination.
2884 * If dumping core, save the signal number for the debugger. Calls exit and
2885 * does not return.
2886 */
2887 void
sigexit(td,sig)2888 sigexit(td, sig)
2889 struct thread *td;
2890 int sig;
2891 {
2892 struct proc *p = td->td_proc;
2893
2894 PROC_LOCK_ASSERT(p, MA_OWNED);
2895 p->p_acflag |= AXSIG;
2896 /*
2897 * We must be single-threading to generate a core dump. This
2898 * ensures that the registers in the core file are up-to-date.
2899 * Also, the ELF dump handler assumes that the thread list doesn't
2900 * change out from under it.
2901 *
2902 * XXX If another thread attempts to single-thread before us
2903 * (e.g. via fork()), we won't get a dump at all.
2904 */
2905 if ((sigprop(sig) & SA_CORE) && (thread_single(SINGLE_NO_EXIT) == 0)) {
2906 p->p_sig = sig;
2907 /*
2908 * Log signals which would cause core dumps
2909 * (Log as LOG_INFO to appease those who don't want
2910 * these messages.)
2911 * XXX : Todo, as well as euid, write out ruid too
2912 * Note that coredump() drops proc lock.
2913 */
2914 if (coredump(td) == 0)
2915 sig |= WCOREFLAG;
2916 if (kern_logsigexit)
2917 log(LOG_INFO,
2918 "pid %d (%s), uid %d: exited on signal %d%s\n",
2919 p->p_pid, p->p_comm,
2920 td->td_ucred ? td->td_ucred->cr_uid : -1,
2921 sig &~ WCOREFLAG,
2922 sig & WCOREFLAG ? " (core dumped)" : "");
2923 } else
2924 PROC_UNLOCK(p);
2925 exit1(td, W_EXITCODE(0, sig));
2926 /* NOTREACHED */
2927 }
2928
2929 /*
2930 * Send queued SIGCHLD to parent when child process's state
2931 * is changed.
2932 */
2933 static void
sigparent(struct proc * p,int reason,int status)2934 sigparent(struct proc *p, int reason, int status)
2935 {
2936 PROC_LOCK_ASSERT(p, MA_OWNED);
2937 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
2938
2939 if (p->p_ksi != NULL) {
2940 p->p_ksi->ksi_signo = SIGCHLD;
2941 p->p_ksi->ksi_code = reason;
2942 p->p_ksi->ksi_status = status;
2943 p->p_ksi->ksi_pid = p->p_pid;
2944 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
2945 if (KSI_ONQ(p->p_ksi))
2946 return;
2947 }
2948 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
2949 }
2950
2951 static void
childproc_jobstate(struct proc * p,int reason,int sig)2952 childproc_jobstate(struct proc *p, int reason, int sig)
2953 {
2954 struct sigacts *ps;
2955
2956 PROC_LOCK_ASSERT(p, MA_OWNED);
2957 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
2958
2959 /*
2960 * Wake up parent sleeping in kern_wait(), also send
2961 * SIGCHLD to parent, but SIGCHLD does not guarantee
2962 * that parent will awake, because parent may masked
2963 * the signal.
2964 */
2965 p->p_pptr->p_flag |= P_STATCHILD;
2966 wakeup(p->p_pptr);
2967
2968 ps = p->p_pptr->p_sigacts;
2969 mtx_lock(&ps->ps_mtx);
2970 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
2971 mtx_unlock(&ps->ps_mtx);
2972 sigparent(p, reason, sig);
2973 } else
2974 mtx_unlock(&ps->ps_mtx);
2975 }
2976
2977 void
childproc_stopped(struct proc * p,int reason)2978 childproc_stopped(struct proc *p, int reason)
2979 {
2980 /* p_xstat is a plain signal number, not a full wait() status here. */
2981 childproc_jobstate(p, reason, p->p_xstat);
2982 }
2983
2984 void
childproc_continued(struct proc * p)2985 childproc_continued(struct proc *p)
2986 {
2987 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
2988 }
2989
2990 void
childproc_exited(struct proc * p)2991 childproc_exited(struct proc *p)
2992 {
2993 int reason;
2994 int xstat = p->p_xstat; /* convert to int */
2995 int status;
2996
2997 if (WCOREDUMP(xstat))
2998 reason = CLD_DUMPED, status = WTERMSIG(xstat);
2999 else if (WIFSIGNALED(xstat))
3000 reason = CLD_KILLED, status = WTERMSIG(xstat);
3001 else
3002 reason = CLD_EXITED, status = WEXITSTATUS(xstat);
3003 /*
3004 * XXX avoid calling wakeup(p->p_pptr), the work is
3005 * done in exit1().
3006 */
3007 sigparent(p, reason, status);
3008 }
3009
3010 /*
3011 * We only have 1 character for the core count in the format
3012 * string, so the range will be 0-9
3013 */
3014 #define MAX_NUM_CORES 10
3015 static int num_cores = 5;
3016
3017 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3018 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3019 {
3020 int error;
3021 int new_val;
3022
3023 new_val = num_cores;
3024 error = sysctl_handle_int(oidp, &new_val, 0, req);
3025 if (error != 0 || req->newptr == NULL)
3026 return (error);
3027 if (new_val > MAX_NUM_CORES)
3028 new_val = MAX_NUM_CORES;
3029 if (new_val < 0)
3030 new_val = 0;
3031 num_cores = new_val;
3032 return (0);
3033 }
3034 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
3035 0, sizeof(int), sysctl_debug_num_cores_check, "I", "");
3036
3037 #if defined(COMPRESS_USER_CORES)
3038 int compress_user_cores = 1;
3039 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RW,
3040 &compress_user_cores, 0, "");
3041
3042 int compress_user_cores_gzlevel = -1; /* default level */
3043 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RW,
3044 &compress_user_cores_gzlevel, -1, "user core gz compression level");
3045
3046 #define GZ_SUFFIX ".gz"
3047 #define GZ_SUFFIX_LEN 3
3048 #endif
3049
3050 static char corefilename[MAXPATHLEN] = {"%N.core"};
3051 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
3052 sizeof(corefilename), "process corefile name format string");
3053
3054 /*
3055 * expand_name(name, uid, pid, td, compress)
3056 * Expand the name described in corefilename, using name, uid, and pid.
3057 * corefilename is a printf-like string, with three format specifiers:
3058 * %N name of process ("name")
3059 * %P process id (pid)
3060 * %U user id (uid)
3061 * For example, "%N.core" is the default; they can be disabled completely
3062 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3063 * This is controlled by the sysctl variable kern.corefile (see above).
3064 */
3065 static char *
expand_name(const char * name,uid_t uid,pid_t pid,struct thread * td,int compress)3066 expand_name(const char *name, uid_t uid, pid_t pid, struct thread *td,
3067 int compress)
3068 {
3069 struct sbuf sb;
3070 const char *format;
3071 char *temp;
3072 size_t i;
3073 int indexpos;
3074 char *hostname;
3075
3076 hostname = NULL;
3077 format = corefilename;
3078 temp = malloc(MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
3079 if (temp == NULL)
3080 return (NULL);
3081 indexpos = -1;
3082 (void)sbuf_new(&sb, temp, MAXPATHLEN, SBUF_FIXEDLEN);
3083 for (i = 0; format[i]; i++) {
3084 switch (format[i]) {
3085 case '%': /* Format character */
3086 i++;
3087 switch (format[i]) {
3088 case '%':
3089 sbuf_putc(&sb, '%');
3090 break;
3091 case 'H': /* hostname */
3092 if (hostname == NULL) {
3093 hostname = malloc(MAXHOSTNAMELEN,
3094 M_TEMP, M_NOWAIT);
3095 if (hostname == NULL) {
3096 log(LOG_ERR,
3097 "pid %ld (%s), uid (%lu): "
3098 "unable to alloc memory "
3099 "for corefile hostname\n",
3100 (long)pid, name,
3101 (u_long)uid);
3102 goto nomem;
3103 }
3104 }
3105 getcredhostname(td->td_ucred, hostname,
3106 MAXHOSTNAMELEN);
3107 sbuf_printf(&sb, "%s", hostname);
3108 break;
3109 case 'I': /* autoincrementing index */
3110 sbuf_printf(&sb, "0");
3111 indexpos = sbuf_len(&sb) - 1;
3112 break;
3113 case 'N': /* process name */
3114 sbuf_printf(&sb, "%s", name);
3115 break;
3116 case 'P': /* process id */
3117 sbuf_printf(&sb, "%u", pid);
3118 break;
3119 case 'U': /* user id */
3120 sbuf_printf(&sb, "%u", uid);
3121 break;
3122 default:
3123 log(LOG_ERR,
3124 "Unknown format character %c in "
3125 "corename `%s'\n", format[i], format);
3126 }
3127 break;
3128 default:
3129 sbuf_putc(&sb, format[i]);
3130 }
3131 }
3132 free(hostname, M_TEMP);
3133 #ifdef COMPRESS_USER_CORES
3134 if (compress) {
3135 sbuf_printf(&sb, GZ_SUFFIX);
3136 }
3137 #endif
3138 if (sbuf_error(&sb) != 0) {
3139 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
3140 "long\n", (long)pid, name, (u_long)uid);
3141 nomem:
3142 sbuf_delete(&sb);
3143 free(temp, M_TEMP);
3144 return (NULL);
3145 }
3146 sbuf_finish(&sb);
3147 sbuf_delete(&sb);
3148
3149 /*
3150 * If the core format has a %I in it, then we need to check
3151 * for existing corefiles before returning a name.
3152 * To do this we iterate over 0..num_cores to find a
3153 * non-existing core file name to use.
3154 */
3155 if (indexpos != -1) {
3156 struct nameidata nd;
3157 int error, n;
3158 int flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW;
3159 int cmode = S_IRUSR | S_IWUSR;
3160 int vfslocked;
3161
3162 for (n = 0; n < num_cores; n++) {
3163 temp[indexpos] = '0' + n;
3164 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE,
3165 temp, td);
3166 error = vn_open(&nd, &flags, cmode, NULL);
3167 if (error) {
3168 if (error == EEXIST) {
3169 continue;
3170 }
3171 log(LOG_ERR,
3172 "pid %d (%s), uid (%u): Path `%s' failed "
3173 "on initial open test, error = %d\n",
3174 pid, name, uid, temp, error);
3175 free(temp, M_TEMP);
3176 return (NULL);
3177 }
3178 vfslocked = NDHASGIANT(&nd);
3179 NDFREE(&nd, NDF_ONLY_PNBUF);
3180 VOP_UNLOCK(nd.ni_vp, 0);
3181 error = vn_close(nd.ni_vp, FWRITE, td->td_ucred, td);
3182 VFS_UNLOCK_GIANT(vfslocked);
3183 if (error) {
3184 log(LOG_ERR,
3185 "pid %d (%s), uid (%u): Path `%s' failed "
3186 "on close after initial open test, "
3187 "error = %d\n",
3188 pid, name, uid, temp, error);
3189 free(temp, M_TEMP);
3190 return (NULL);
3191 }
3192 break;
3193 }
3194 }
3195 return (temp);
3196 }
3197
3198 /*
3199 * Dump a process' core. The main routine does some
3200 * policy checking, and creates the name of the coredump;
3201 * then it passes on a vnode and a size limit to the process-specific
3202 * coredump routine if there is one; if there _is not_ one, it returns
3203 * ENOSYS; otherwise it returns the error from the process-specific routine.
3204 */
3205
3206 static int
coredump(struct thread * td)3207 coredump(struct thread *td)
3208 {
3209 struct proc *p = td->td_proc;
3210 register struct vnode *vp;
3211 register struct ucred *cred = td->td_ucred;
3212 struct flock lf;
3213 struct nameidata nd;
3214 struct vattr vattr;
3215 int error, error1, flags, locked;
3216 struct mount *mp;
3217 char *name; /* name of corefile */
3218 off_t limit;
3219 int vfslocked;
3220 int compress;
3221
3222 #ifdef COMPRESS_USER_CORES
3223 compress = compress_user_cores;
3224 #else
3225 compress = 0;
3226 #endif
3227 PROC_LOCK_ASSERT(p, MA_OWNED);
3228 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
3229 _STOPEVENT(p, S_CORE, 0);
3230
3231 name = expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid, td,
3232 compress);
3233 if (name == NULL) {
3234 PROC_UNLOCK(p);
3235 #ifdef AUDIT
3236 audit_proc_coredump(td, NULL, EINVAL);
3237 #endif
3238 return (EINVAL);
3239 }
3240 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) {
3241 PROC_UNLOCK(p);
3242 #ifdef AUDIT
3243 audit_proc_coredump(td, name, EFAULT);
3244 #endif
3245 free(name, M_TEMP);
3246 return (EFAULT);
3247 }
3248
3249 /*
3250 * Note that the bulk of limit checking is done after
3251 * the corefile is created. The exception is if the limit
3252 * for corefiles is 0, in which case we don't bother
3253 * creating the corefile at all. This layout means that
3254 * a corefile is truncated instead of not being created,
3255 * if it is larger than the limit.
3256 */
3257 limit = (off_t)lim_cur(p, RLIMIT_CORE);
3258 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
3259 PROC_UNLOCK(p);
3260 #ifdef AUDIT
3261 audit_proc_coredump(td, name, EFBIG);
3262 #endif
3263 free(name, M_TEMP);
3264 return (EFBIG);
3265 }
3266 PROC_UNLOCK(p);
3267
3268 restart:
3269 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, name, td);
3270 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3271 error = vn_open_cred(&nd, &flags, S_IRUSR | S_IWUSR, VN_OPEN_NOAUDIT,
3272 cred, NULL);
3273 if (error) {
3274 #ifdef AUDIT
3275 audit_proc_coredump(td, name, error);
3276 #endif
3277 free(name, M_TEMP);
3278 return (error);
3279 }
3280 vfslocked = NDHASGIANT(&nd);
3281 NDFREE(&nd, NDF_ONLY_PNBUF);
3282 vp = nd.ni_vp;
3283
3284 /* Don't dump to non-regular files or files with links. */
3285 if (vp->v_type != VREG ||
3286 VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1) {
3287 VOP_UNLOCK(vp, 0);
3288 error = EFAULT;
3289 goto close;
3290 }
3291
3292 VOP_UNLOCK(vp, 0);
3293 lf.l_whence = SEEK_SET;
3294 lf.l_start = 0;
3295 lf.l_len = 0;
3296 lf.l_type = F_WRLCK;
3297 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
3298
3299 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
3300 lf.l_type = F_UNLCK;
3301 if (locked)
3302 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3303 if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
3304 goto out;
3305 if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
3306 goto out;
3307 VFS_UNLOCK_GIANT(vfslocked);
3308 goto restart;
3309 }
3310
3311 VATTR_NULL(&vattr);
3312 vattr.va_size = 0;
3313 if (set_core_nodump_flag)
3314 vattr.va_flags = UF_NODUMP;
3315 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
3316 VOP_SETATTR(vp, &vattr, cred);
3317 VOP_UNLOCK(vp, 0);
3318 vn_finished_write(mp);
3319 PROC_LOCK(p);
3320 p->p_acflag |= ACORE;
3321 PROC_UNLOCK(p);
3322
3323 error = p->p_sysent->sv_coredump ?
3324 p->p_sysent->sv_coredump(td, vp, limit, compress ? IMGACT_CORE_COMPRESS : 0) :
3325 ENOSYS;
3326
3327 if (locked) {
3328 lf.l_type = F_UNLCK;
3329 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
3330 }
3331 close:
3332 error1 = vn_close(vp, FWRITE, cred, td);
3333 if (error == 0)
3334 error = error1;
3335 out:
3336 #ifdef AUDIT
3337 audit_proc_coredump(td, name, error);
3338 #endif
3339 free(name, M_TEMP);
3340 VFS_UNLOCK_GIANT(vfslocked);
3341 return (error);
3342 }
3343
3344 /*
3345 * Nonexistent system call-- signal process (may want to handle it). Flag
3346 * error in case process won't see signal immediately (blocked or ignored).
3347 */
3348 #ifndef _SYS_SYSPROTO_H_
3349 struct nosys_args {
3350 int dummy;
3351 };
3352 #endif
3353 /* ARGSUSED */
3354 int
nosys(td,args)3355 nosys(td, args)
3356 struct thread *td;
3357 struct nosys_args *args;
3358 {
3359 struct proc *p = td->td_proc;
3360
3361 PROC_LOCK(p);
3362 tdsignal(td, SIGSYS);
3363 PROC_UNLOCK(p);
3364 return (ENOSYS);
3365 }
3366
3367 /*
3368 * Send a SIGIO or SIGURG signal to a process or process group using stored
3369 * credentials rather than those of the current process.
3370 */
3371 void
pgsigio(sigiop,sig,checkctty)3372 pgsigio(sigiop, sig, checkctty)
3373 struct sigio **sigiop;
3374 int sig, checkctty;
3375 {
3376 ksiginfo_t ksi;
3377 struct sigio *sigio;
3378
3379 ksiginfo_init(&ksi);
3380 ksi.ksi_signo = sig;
3381 ksi.ksi_code = SI_KERNEL;
3382
3383 SIGIO_LOCK();
3384 sigio = *sigiop;
3385 if (sigio == NULL) {
3386 SIGIO_UNLOCK();
3387 return;
3388 }
3389 if (sigio->sio_pgid > 0) {
3390 PROC_LOCK(sigio->sio_proc);
3391 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3392 kern_psignal(sigio->sio_proc, sig);
3393 PROC_UNLOCK(sigio->sio_proc);
3394 } else if (sigio->sio_pgid < 0) {
3395 struct proc *p;
3396
3397 PGRP_LOCK(sigio->sio_pgrp);
3398 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3399 PROC_LOCK(p);
3400 if (p->p_state == PRS_NORMAL &&
3401 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3402 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3403 kern_psignal(p, sig);
3404 PROC_UNLOCK(p);
3405 }
3406 PGRP_UNLOCK(sigio->sio_pgrp);
3407 }
3408 SIGIO_UNLOCK();
3409 }
3410
3411 static int
filt_sigattach(struct knote * kn)3412 filt_sigattach(struct knote *kn)
3413 {
3414 struct proc *p = curproc;
3415
3416 kn->kn_ptr.p_proc = p;
3417 kn->kn_flags |= EV_CLEAR; /* automatically set */
3418
3419 knlist_add(&p->p_klist, kn, 0);
3420
3421 return (0);
3422 }
3423
3424 static void
filt_sigdetach(struct knote * kn)3425 filt_sigdetach(struct knote *kn)
3426 {
3427 struct proc *p = kn->kn_ptr.p_proc;
3428
3429 knlist_remove(&p->p_klist, kn, 0);
3430 }
3431
3432 /*
3433 * signal knotes are shared with proc knotes, so we apply a mask to
3434 * the hint in order to differentiate them from process hints. This
3435 * could be avoided by using a signal-specific knote list, but probably
3436 * isn't worth the trouble.
3437 */
3438 static int
filt_signal(struct knote * kn,long hint)3439 filt_signal(struct knote *kn, long hint)
3440 {
3441
3442 if (hint & NOTE_SIGNAL) {
3443 hint &= ~NOTE_SIGNAL;
3444
3445 if (kn->kn_id == hint)
3446 kn->kn_data++;
3447 }
3448 return (kn->kn_data != 0);
3449 }
3450
3451 struct sigacts *
sigacts_alloc(void)3452 sigacts_alloc(void)
3453 {
3454 struct sigacts *ps;
3455
3456 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3457 ps->ps_refcnt = 1;
3458 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3459 return (ps);
3460 }
3461
3462 void
sigacts_free(struct sigacts * ps)3463 sigacts_free(struct sigacts *ps)
3464 {
3465
3466 mtx_lock(&ps->ps_mtx);
3467 ps->ps_refcnt--;
3468 if (ps->ps_refcnt == 0) {
3469 mtx_destroy(&ps->ps_mtx);
3470 free(ps, M_SUBPROC);
3471 } else
3472 mtx_unlock(&ps->ps_mtx);
3473 }
3474
3475 struct sigacts *
sigacts_hold(struct sigacts * ps)3476 sigacts_hold(struct sigacts *ps)
3477 {
3478 mtx_lock(&ps->ps_mtx);
3479 ps->ps_refcnt++;
3480 mtx_unlock(&ps->ps_mtx);
3481 return (ps);
3482 }
3483
3484 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3485 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3486 {
3487
3488 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3489 mtx_lock(&src->ps_mtx);
3490 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3491 mtx_unlock(&src->ps_mtx);
3492 }
3493
3494 int
sigacts_shared(struct sigacts * ps)3495 sigacts_shared(struct sigacts *ps)
3496 {
3497 int shared;
3498
3499 mtx_lock(&ps->ps_mtx);
3500 shared = ps->ps_refcnt > 1;
3501 mtx_unlock(&ps->ps_mtx);
3502 return (shared);
3503 }
3504