1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include "opt_capsicum.h"
38 #include "opt_ktrace.h"
39
40 #include <sys/param.h>
41 #include <sys/capsicum.h>
42 #include <sys/ctype.h>
43 #include <sys/systm.h>
44 #include <sys/signalvar.h>
45 #include <sys/vnode.h>
46 #include <sys/acct.h>
47 #include <sys/capsicum.h>
48 #include <sys/condvar.h>
49 #include <sys/devctl.h>
50 #include <sys/event.h>
51 #include <sys/exec.h>
52 #include <sys/fcntl.h>
53 #include <sys/imgact.h>
54 #include <sys/jail.h>
55 #include <sys/kernel.h>
56 #include <sys/ktr.h>
57 #include <sys/ktrace.h>
58 #include <sys/limits.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/mutex.h>
62 #include <sys/refcount.h>
63 #include <sys/namei.h>
64 #include <sys/proc.h>
65 #include <sys/procdesc.h>
66 #include <sys/ptrace.h>
67 #include <sys/posix4.h>
68 #include <sys/racct.h>
69 #include <sys/resourcevar.h>
70 #include <sys/sdt.h>
71 #include <sys/sbuf.h>
72 #include <sys/sleepqueue.h>
73 #include <sys/smp.h>
74 #include <sys/stat.h>
75 #include <sys/sx.h>
76 #include <sys/syscall.h>
77 #include <sys/syscallsubr.h>
78 #include <sys/sysctl.h>
79 #include <sys/sysent.h>
80 #include <sys/syslog.h>
81 #include <sys/sysproto.h>
82 #include <sys/timers.h>
83 #include <sys/ucoredump.h>
84 #include <sys/unistd.h>
85 #include <sys/vmmeter.h>
86 #include <sys/wait.h>
87 #include <vm/vm.h>
88 #include <vm/vm_extern.h>
89 #include <vm/uma.h>
90
91 #include <machine/cpu.h>
92
93 #include <security/audit/audit.h>
94
95 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
96
97 SDT_PROVIDER_DECLARE(proc);
98 SDT_PROBE_DEFINE3(proc, , , signal__send,
99 "struct thread *", "struct proc *", "int");
100 SDT_PROBE_DEFINE2(proc, , , signal__clear,
101 "int", "ksiginfo_t *");
102 SDT_PROBE_DEFINE3(proc, , , signal__discard,
103 "struct thread *", "struct proc *", "int");
104
105 static int killpg1(struct thread *td, int sig, int pgid, int all,
106 ksiginfo_t *ksi);
107 static int issignal(struct thread *td);
108 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
109 static int sigprop(int sig);
110 static void tdsigwakeup(struct thread *, int, sig_t, int);
111 static bool sig_suspend_threads(struct thread *, struct proc *);
112 static int filt_sigattach(struct knote *kn);
113 static void filt_sigdetach(struct knote *kn);
114 static int filt_signal(struct knote *kn, long hint);
115 static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock);
116 static void sigqueue_start(void *);
117 static void sigfastblock_setpend(struct thread *td, bool resched);
118 static void sig_handle_first_stop(struct thread *td, struct proc *p,
119 int sig);
120
121 static uma_zone_t ksiginfo_zone = NULL;
122 const struct filterops sig_filtops = {
123 .f_isfd = 0,
124 .f_attach = filt_sigattach,
125 .f_detach = filt_sigdetach,
126 .f_event = filt_signal,
127 };
128
129 static int kern_forcesigexit = 1;
130 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
131 &kern_forcesigexit, 0, "Force trap signal to be handled");
132
133 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
134 "POSIX real time signal");
135
136 static int max_pending_per_proc = 128;
137 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
138 &max_pending_per_proc, 0, "Max pending signals per proc");
139
140 static int preallocate_siginfo = 1024;
141 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
142 &preallocate_siginfo, 0, "Preallocated signal memory size");
143
144 static int signal_overflow = 0;
145 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
146 &signal_overflow, 0, "Number of signals overflew");
147
148 static int signal_alloc_fail = 0;
149 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
150 &signal_alloc_fail, 0, "signals failed to be allocated");
151
152 static int kern_lognosys = 0;
153 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
154 "Log invalid syscalls");
155
156 static int kern_signosys = 1;
157 SYSCTL_INT(_kern, OID_AUTO, signosys, CTLFLAG_RWTUN, &kern_signosys, 0,
158 "Send SIGSYS on return from invalid syscall");
159
160 __read_frequently bool sigfastblock_fetch_always = false;
161 SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN,
162 &sigfastblock_fetch_always, 0,
163 "Fetch sigfastblock word on each syscall entry for proper "
164 "blocking semantic");
165
166 static bool kern_sig_discard_ign = true;
167 SYSCTL_BOOL(_kern, OID_AUTO, sig_discard_ign, CTLFLAG_RWTUN,
168 &kern_sig_discard_ign, 0,
169 "Discard ignored signals on delivery, otherwise queue them to "
170 "the target queue");
171
172 bool pt_attach_transparent = true;
173 SYSCTL_BOOL(_debug, OID_AUTO, ptrace_attach_transparent, CTLFLAG_RWTUN,
174 &pt_attach_transparent, 0,
175 "Hide wakes from PT_ATTACH on interruptible sleeps");
176
177 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
178
179 /*
180 * Policy -- Can ucred cr1 send SIGIO to process cr2?
181 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
182 * in the right situations.
183 */
184 #define CANSIGIO(cr1, cr2) \
185 ((cr1)->cr_uid == 0 || \
186 (cr1)->cr_ruid == (cr2)->cr_ruid || \
187 (cr1)->cr_uid == (cr2)->cr_ruid || \
188 (cr1)->cr_ruid == (cr2)->cr_uid || \
189 (cr1)->cr_uid == (cr2)->cr_uid)
190
191 /*
192 * Signal properties and actions.
193 * The array below categorizes the signals and their default actions
194 * according to the following properties:
195 */
196 #define SIGPROP_KILL 0x01 /* terminates process by default */
197 #define SIGPROP_CORE 0x02 /* ditto and coredumps */
198 #define SIGPROP_STOP 0x04 /* suspend process */
199 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */
200 #define SIGPROP_IGNORE 0x10 /* ignore by default */
201 #define SIGPROP_CONT 0x20 /* continue if suspended */
202
203 static const int sigproptbl[NSIG] = {
204 [SIGHUP] = SIGPROP_KILL,
205 [SIGINT] = SIGPROP_KILL,
206 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE,
207 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE,
208 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE,
209 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE,
210 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE,
211 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE,
212 [SIGKILL] = SIGPROP_KILL,
213 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE,
214 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE,
215 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE,
216 [SIGPIPE] = SIGPROP_KILL,
217 [SIGALRM] = SIGPROP_KILL,
218 [SIGTERM] = SIGPROP_KILL,
219 [SIGURG] = SIGPROP_IGNORE,
220 [SIGSTOP] = SIGPROP_STOP,
221 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP,
222 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT,
223 [SIGCHLD] = SIGPROP_IGNORE,
224 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP,
225 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP,
226 [SIGIO] = SIGPROP_IGNORE,
227 [SIGXCPU] = SIGPROP_KILL,
228 [SIGXFSZ] = SIGPROP_KILL,
229 [SIGVTALRM] = SIGPROP_KILL,
230 [SIGPROF] = SIGPROP_KILL,
231 [SIGWINCH] = SIGPROP_IGNORE,
232 [SIGINFO] = SIGPROP_IGNORE,
233 [SIGUSR1] = SIGPROP_KILL,
234 [SIGUSR2] = SIGPROP_KILL,
235 };
236
237 #define _SIG_FOREACH_ADVANCE(i, set) ({ \
238 int __found; \
239 for (;;) { \
240 if (__bits != 0) { \
241 int __sig = ffs(__bits); \
242 __bits &= ~(1u << (__sig - 1)); \
243 sig = __i * sizeof((set)->__bits[0]) * NBBY + __sig; \
244 __found = 1; \
245 break; \
246 } \
247 if (++__i == _SIG_WORDS) { \
248 __found = 0; \
249 break; \
250 } \
251 __bits = (set)->__bits[__i]; \
252 } \
253 __found != 0; \
254 })
255
256 #define SIG_FOREACH(i, set) \
257 for (int32_t __i = -1, __bits = 0; \
258 _SIG_FOREACH_ADVANCE(i, set); ) \
259
260 static sigset_t fastblock_mask;
261
262 static void
ast_sig(struct thread * td,int tda)263 ast_sig(struct thread *td, int tda)
264 {
265 struct proc *p;
266 int old_boundary, sig;
267 bool resched_sigs;
268
269 p = td->td_proc;
270
271 #ifdef DIAGNOSTIC
272 if (p->p_numthreads == 1 && (tda & (TDAI(TDA_SIG) |
273 TDAI(TDA_AST))) == 0) {
274 PROC_LOCK(p);
275 thread_lock(td);
276 /*
277 * Note that TDA_SIG should be re-read from
278 * td_ast, since signal might have been delivered
279 * after we cleared td_flags above. This is one of
280 * the reason for looping check for AST condition.
281 * See comment in userret() about P_PPWAIT.
282 */
283 if ((p->p_flag & P_PPWAIT) == 0 &&
284 (td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
285 if (SIGPENDING(td) && ((tda | td->td_ast) &
286 (TDAI(TDA_SIG) | TDAI(TDA_AST))) == 0) {
287 thread_unlock(td); /* fix dumps */
288 panic(
289 "failed2 to set signal flags for ast p %p "
290 "td %p tda %#x td_ast %#x fl %#x",
291 p, td, tda, td->td_ast, td->td_flags);
292 }
293 }
294 thread_unlock(td);
295 PROC_UNLOCK(p);
296 }
297 #endif
298
299 /*
300 * Check for signals. Unlocked reads of p_pendingcnt or
301 * p_siglist might cause process-directed signal to be handled
302 * later.
303 */
304 if ((tda & TDAI(TDA_SIG)) != 0 || p->p_pendingcnt > 0 ||
305 !SIGISEMPTY(p->p_siglist)) {
306 sigfastblock_fetch(td);
307 PROC_LOCK(p);
308 old_boundary = ~TDB_BOUNDARY | (td->td_dbgflags & TDB_BOUNDARY);
309 td->td_dbgflags |= TDB_BOUNDARY;
310 mtx_lock(&p->p_sigacts->ps_mtx);
311 while ((sig = cursig(td)) != 0) {
312 KASSERT(sig >= 0, ("sig %d", sig));
313 postsig(sig);
314 }
315 mtx_unlock(&p->p_sigacts->ps_mtx);
316 td->td_dbgflags &= old_boundary;
317 PROC_UNLOCK(p);
318 resched_sigs = true;
319 } else {
320 resched_sigs = false;
321 }
322
323 /*
324 * Handle deferred update of the fast sigblock value, after
325 * the postsig() loop was performed.
326 */
327 sigfastblock_setpend(td, resched_sigs);
328
329 /*
330 * Clear td_sa.code: signal to ptrace that syscall arguments
331 * are unavailable after this point. This AST handler is the
332 * last chance for ptracestop() to signal the tracer before
333 * the tracee returns to userspace.
334 */
335 td->td_sa.code = 0;
336 }
337
338 static void
ast_sigsuspend(struct thread * td,int tda __unused)339 ast_sigsuspend(struct thread *td, int tda __unused)
340 {
341 MPASS((td->td_pflags & TDP_OLDMASK) != 0);
342 td->td_pflags &= ~TDP_OLDMASK;
343 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
344 }
345
346 static void
sigqueue_start(void * dummy __unused)347 sigqueue_start(void *dummy __unused)
348 {
349 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
350 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
351 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
352 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
353 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
354 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
355 SIGFILLSET(fastblock_mask);
356 SIG_CANTMASK(fastblock_mask);
357 ast_register(TDA_SIG, ASTR_UNCOND, 0, ast_sig);
358
359 /*
360 * TDA_PSELECT is for the case where the signal mask should be restored
361 * before delivering any signals so that we do not deliver any that are
362 * blocked by the normal thread mask. It is mutually exclusive with
363 * TDA_SIGSUSPEND, which should be used if we *do* want to deliver
364 * signals that are normally blocked, e.g., if it interrupted our sleep.
365 */
366 ast_register(TDA_PSELECT, ASTR_ASTF_REQUIRED | ASTR_TDP,
367 TDP_OLDMASK, ast_sigsuspend);
368 ast_register(TDA_SIGSUSPEND, ASTR_ASTF_REQUIRED | ASTR_TDP,
369 TDP_OLDMASK, ast_sigsuspend);
370 }
371
372 ksiginfo_t *
ksiginfo_alloc(int mwait)373 ksiginfo_alloc(int mwait)
374 {
375 MPASS(mwait == M_WAITOK || mwait == M_NOWAIT);
376
377 if (ksiginfo_zone == NULL)
378 return (NULL);
379 return (uma_zalloc(ksiginfo_zone, mwait | M_ZERO));
380 }
381
382 void
ksiginfo_free(ksiginfo_t * ksi)383 ksiginfo_free(ksiginfo_t *ksi)
384 {
385 uma_zfree(ksiginfo_zone, ksi);
386 }
387
388 static __inline bool
ksiginfo_tryfree(ksiginfo_t * ksi)389 ksiginfo_tryfree(ksiginfo_t *ksi)
390 {
391 if ((ksi->ksi_flags & KSI_EXT) == 0) {
392 uma_zfree(ksiginfo_zone, ksi);
393 return (true);
394 }
395 return (false);
396 }
397
398 void
sigqueue_init(sigqueue_t * list,struct proc * p)399 sigqueue_init(sigqueue_t *list, struct proc *p)
400 {
401 SIGEMPTYSET(list->sq_signals);
402 SIGEMPTYSET(list->sq_kill);
403 SIGEMPTYSET(list->sq_ptrace);
404 TAILQ_INIT(&list->sq_list);
405 list->sq_proc = p;
406 list->sq_flags = SQ_INIT;
407 }
408
409 /*
410 * Get a signal's ksiginfo.
411 * Return:
412 * 0 - signal not found
413 * others - signal number
414 */
415 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)416 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
417 {
418 struct proc *p = sq->sq_proc;
419 struct ksiginfo *ksi, *next;
420 int count = 0;
421
422 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
423
424 if (!SIGISMEMBER(sq->sq_signals, signo))
425 return (0);
426
427 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
428 count++;
429 SIGDELSET(sq->sq_ptrace, signo);
430 si->ksi_flags |= KSI_PTRACE;
431 }
432 if (SIGISMEMBER(sq->sq_kill, signo)) {
433 count++;
434 if (count == 1)
435 SIGDELSET(sq->sq_kill, signo);
436 }
437
438 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
439 if (ksi->ksi_signo == signo) {
440 if (count == 0) {
441 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
442 ksi->ksi_sigq = NULL;
443 ksiginfo_copy(ksi, si);
444 if (ksiginfo_tryfree(ksi) && p != NULL)
445 p->p_pendingcnt--;
446 }
447 if (++count > 1)
448 break;
449 }
450 }
451
452 if (count <= 1)
453 SIGDELSET(sq->sq_signals, signo);
454 si->ksi_signo = signo;
455 return (signo);
456 }
457
458 void
sigqueue_take(ksiginfo_t * ksi)459 sigqueue_take(ksiginfo_t *ksi)
460 {
461 struct ksiginfo *kp;
462 struct proc *p;
463 sigqueue_t *sq;
464
465 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
466 return;
467
468 p = sq->sq_proc;
469 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
470 ksi->ksi_sigq = NULL;
471 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
472 p->p_pendingcnt--;
473
474 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
475 kp = TAILQ_NEXT(kp, ksi_link)) {
476 if (kp->ksi_signo == ksi->ksi_signo)
477 break;
478 }
479 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
480 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
481 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
482 }
483
484 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)485 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
486 {
487 struct proc *p = sq->sq_proc;
488 struct ksiginfo *ksi;
489 int ret = 0;
490
491 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
492
493 /*
494 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
495 * for these signals.
496 */
497 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
498 SIGADDSET(sq->sq_kill, signo);
499 goto out_set_bit;
500 }
501
502 /* directly insert the ksi, don't copy it */
503 if (si->ksi_flags & KSI_INS) {
504 if (si->ksi_flags & KSI_HEAD)
505 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
506 else
507 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
508 si->ksi_sigq = sq;
509 goto out_set_bit;
510 }
511
512 if (__predict_false(ksiginfo_zone == NULL)) {
513 SIGADDSET(sq->sq_kill, signo);
514 goto out_set_bit;
515 }
516
517 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
518 signal_overflow++;
519 ret = EAGAIN;
520 } else if ((ksi = ksiginfo_alloc(M_NOWAIT)) == NULL) {
521 signal_alloc_fail++;
522 ret = EAGAIN;
523 } else {
524 if (p != NULL)
525 p->p_pendingcnt++;
526 ksiginfo_copy(si, ksi);
527 ksi->ksi_signo = signo;
528 if (si->ksi_flags & KSI_HEAD)
529 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
530 else
531 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
532 ksi->ksi_sigq = sq;
533 }
534
535 if (ret != 0) {
536 if ((si->ksi_flags & KSI_PTRACE) != 0) {
537 SIGADDSET(sq->sq_ptrace, signo);
538 ret = 0;
539 goto out_set_bit;
540 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
541 (si->ksi_flags & KSI_SIGQ) == 0) {
542 SIGADDSET(sq->sq_kill, signo);
543 ret = 0;
544 goto out_set_bit;
545 }
546 return (ret);
547 }
548
549 out_set_bit:
550 SIGADDSET(sq->sq_signals, signo);
551 return (ret);
552 }
553
554 void
sigqueue_flush(sigqueue_t * sq)555 sigqueue_flush(sigqueue_t *sq)
556 {
557 struct proc *p = sq->sq_proc;
558 ksiginfo_t *ksi;
559
560 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
561
562 if (p != NULL)
563 PROC_LOCK_ASSERT(p, MA_OWNED);
564
565 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
566 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
567 ksi->ksi_sigq = NULL;
568 if (ksiginfo_tryfree(ksi) && p != NULL)
569 p->p_pendingcnt--;
570 }
571
572 SIGEMPTYSET(sq->sq_signals);
573 SIGEMPTYSET(sq->sq_kill);
574 SIGEMPTYSET(sq->sq_ptrace);
575 }
576
577 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)578 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
579 {
580 sigset_t tmp;
581 struct proc *p1, *p2;
582 ksiginfo_t *ksi, *next;
583
584 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
585 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
586 p1 = src->sq_proc;
587 p2 = dst->sq_proc;
588 /* Move siginfo to target list */
589 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
590 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
591 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
592 if (p1 != NULL)
593 p1->p_pendingcnt--;
594 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
595 ksi->ksi_sigq = dst;
596 if (p2 != NULL)
597 p2->p_pendingcnt++;
598 }
599 }
600
601 /* Move pending bits to target list */
602 tmp = src->sq_kill;
603 SIGSETAND(tmp, *set);
604 SIGSETOR(dst->sq_kill, tmp);
605 SIGSETNAND(src->sq_kill, tmp);
606
607 tmp = src->sq_ptrace;
608 SIGSETAND(tmp, *set);
609 SIGSETOR(dst->sq_ptrace, tmp);
610 SIGSETNAND(src->sq_ptrace, tmp);
611
612 tmp = src->sq_signals;
613 SIGSETAND(tmp, *set);
614 SIGSETOR(dst->sq_signals, tmp);
615 SIGSETNAND(src->sq_signals, tmp);
616 }
617
618 #if 0
619 static void
620 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
621 {
622 sigset_t set;
623
624 SIGEMPTYSET(set);
625 SIGADDSET(set, signo);
626 sigqueue_move_set(src, dst, &set);
627 }
628 #endif
629
630 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)631 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
632 {
633 struct proc *p = sq->sq_proc;
634 ksiginfo_t *ksi, *next;
635
636 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
637
638 /* Remove siginfo queue */
639 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
640 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
641 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
642 ksi->ksi_sigq = NULL;
643 if (ksiginfo_tryfree(ksi) && p != NULL)
644 p->p_pendingcnt--;
645 }
646 }
647 SIGSETNAND(sq->sq_kill, *set);
648 SIGSETNAND(sq->sq_ptrace, *set);
649 SIGSETNAND(sq->sq_signals, *set);
650 }
651
652 void
sigqueue_delete(sigqueue_t * sq,int signo)653 sigqueue_delete(sigqueue_t *sq, int signo)
654 {
655 sigset_t set;
656
657 SIGEMPTYSET(set);
658 SIGADDSET(set, signo);
659 sigqueue_delete_set(sq, &set);
660 }
661
662 /* Remove a set of signals for a process */
663 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)664 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
665 {
666 sigqueue_t worklist;
667 struct thread *td0;
668
669 PROC_LOCK_ASSERT(p, MA_OWNED);
670
671 sigqueue_init(&worklist, NULL);
672 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
673
674 FOREACH_THREAD_IN_PROC(p, td0)
675 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
676
677 sigqueue_flush(&worklist);
678 }
679
680 void
sigqueue_delete_proc(struct proc * p,int signo)681 sigqueue_delete_proc(struct proc *p, int signo)
682 {
683 sigset_t set;
684
685 SIGEMPTYSET(set);
686 SIGADDSET(set, signo);
687 sigqueue_delete_set_proc(p, &set);
688 }
689
690 static void
sigqueue_delete_stopmask_proc(struct proc * p)691 sigqueue_delete_stopmask_proc(struct proc *p)
692 {
693 sigset_t set;
694
695 SIGEMPTYSET(set);
696 SIGADDSET(set, SIGSTOP);
697 SIGADDSET(set, SIGTSTP);
698 SIGADDSET(set, SIGTTIN);
699 SIGADDSET(set, SIGTTOU);
700 sigqueue_delete_set_proc(p, &set);
701 }
702
703 /*
704 * Determine signal that should be delivered to thread td, the current
705 * thread, 0 if none. If there is a pending stop signal with default
706 * action, the process stops in issignal().
707 */
708 int
cursig(struct thread * td)709 cursig(struct thread *td)
710 {
711 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
712 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
713 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
714 return (SIGPENDING(td) ? issignal(td) : 0);
715 }
716
717 /*
718 * Arrange for ast() to handle unmasked pending signals on return to user
719 * mode. This must be called whenever a signal is added to td_sigqueue or
720 * unmasked in td_sigmask.
721 */
722 void
signotify(struct thread * td)723 signotify(struct thread *td)
724 {
725
726 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
727
728 if (SIGPENDING(td))
729 ast_sched(td, TDA_SIG);
730 }
731
732 /*
733 * Returns 1 (true) if altstack is configured for the thread, and the
734 * passed stack bottom address falls into the altstack range. Handles
735 * the 43 compat special case where the alt stack size is zero.
736 */
737 int
sigonstack(size_t sp)738 sigonstack(size_t sp)
739 {
740 struct thread *td;
741
742 td = curthread;
743 if ((td->td_pflags & TDP_ALTSTACK) == 0)
744 return (0);
745 #if defined(COMPAT_43)
746 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0)
747 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0);
748 #endif
749 return (sp >= (size_t)td->td_sigstk.ss_sp &&
750 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp);
751 }
752
753 static __inline int
sigprop(int sig)754 sigprop(int sig)
755 {
756
757 if (sig > 0 && sig < nitems(sigproptbl))
758 return (sigproptbl[sig]);
759 return (0);
760 }
761
762 bool
sig_do_core(int sig)763 sig_do_core(int sig)
764 {
765
766 return ((sigprop(sig) & SIGPROP_CORE) != 0);
767 }
768
769 static bool
sigact_flag_test(const struct sigaction * act,int flag)770 sigact_flag_test(const struct sigaction *act, int flag)
771 {
772
773 /*
774 * SA_SIGINFO is reset when signal disposition is set to
775 * ignore or default. Other flags are kept according to user
776 * settings.
777 */
778 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
779 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
780 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
781 }
782
783 /*
784 * kern_sigaction
785 * sigaction
786 * freebsd4_sigaction
787 * osigaction
788 */
789 int
kern_sigaction(struct thread * td,int sig,const struct sigaction * act,struct sigaction * oact,int flags)790 kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
791 struct sigaction *oact, int flags)
792 {
793 struct sigacts *ps;
794 struct proc *p = td->td_proc;
795
796 if (!_SIG_VALID(sig))
797 return (EINVAL);
798 if (act != NULL && act->sa_handler != SIG_DFL &&
799 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
800 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
801 SA_NOCLDWAIT | SA_SIGINFO)) != 0)
802 return (EINVAL);
803
804 PROC_LOCK(p);
805 ps = p->p_sigacts;
806 mtx_lock(&ps->ps_mtx);
807 if (oact) {
808 memset(oact, 0, sizeof(*oact));
809 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
810 if (SIGISMEMBER(ps->ps_sigonstack, sig))
811 oact->sa_flags |= SA_ONSTACK;
812 if (!SIGISMEMBER(ps->ps_sigintr, sig))
813 oact->sa_flags |= SA_RESTART;
814 if (SIGISMEMBER(ps->ps_sigreset, sig))
815 oact->sa_flags |= SA_RESETHAND;
816 if (SIGISMEMBER(ps->ps_signodefer, sig))
817 oact->sa_flags |= SA_NODEFER;
818 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
819 oact->sa_flags |= SA_SIGINFO;
820 oact->sa_sigaction =
821 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
822 } else
823 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
824 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
825 oact->sa_flags |= SA_NOCLDSTOP;
826 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
827 oact->sa_flags |= SA_NOCLDWAIT;
828 }
829 if (act) {
830 if ((sig == SIGKILL || sig == SIGSTOP) &&
831 act->sa_handler != SIG_DFL) {
832 mtx_unlock(&ps->ps_mtx);
833 PROC_UNLOCK(p);
834 return (EINVAL);
835 }
836
837 /*
838 * Change setting atomically.
839 */
840
841 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
842 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
843 if (sigact_flag_test(act, SA_SIGINFO)) {
844 ps->ps_sigact[_SIG_IDX(sig)] =
845 (__sighandler_t *)act->sa_sigaction;
846 SIGADDSET(ps->ps_siginfo, sig);
847 } else {
848 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
849 SIGDELSET(ps->ps_siginfo, sig);
850 }
851 if (!sigact_flag_test(act, SA_RESTART))
852 SIGADDSET(ps->ps_sigintr, sig);
853 else
854 SIGDELSET(ps->ps_sigintr, sig);
855 if (sigact_flag_test(act, SA_ONSTACK))
856 SIGADDSET(ps->ps_sigonstack, sig);
857 else
858 SIGDELSET(ps->ps_sigonstack, sig);
859 if (sigact_flag_test(act, SA_RESETHAND))
860 SIGADDSET(ps->ps_sigreset, sig);
861 else
862 SIGDELSET(ps->ps_sigreset, sig);
863 if (sigact_flag_test(act, SA_NODEFER))
864 SIGADDSET(ps->ps_signodefer, sig);
865 else
866 SIGDELSET(ps->ps_signodefer, sig);
867 if (sig == SIGCHLD) {
868 if (act->sa_flags & SA_NOCLDSTOP)
869 ps->ps_flag |= PS_NOCLDSTOP;
870 else
871 ps->ps_flag &= ~PS_NOCLDSTOP;
872 if (act->sa_flags & SA_NOCLDWAIT) {
873 /*
874 * Paranoia: since SA_NOCLDWAIT is implemented
875 * by reparenting the dying child to PID 1 (and
876 * trust it to reap the zombie), PID 1 itself
877 * is forbidden to set SA_NOCLDWAIT.
878 */
879 if (p->p_pid == 1)
880 ps->ps_flag &= ~PS_NOCLDWAIT;
881 else
882 ps->ps_flag |= PS_NOCLDWAIT;
883 } else
884 ps->ps_flag &= ~PS_NOCLDWAIT;
885 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
886 ps->ps_flag |= PS_CLDSIGIGN;
887 else
888 ps->ps_flag &= ~PS_CLDSIGIGN;
889 }
890 /*
891 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
892 * and for signals set to SIG_DFL where the default is to
893 * ignore. However, don't put SIGCONT in ps_sigignore, as we
894 * have to restart the process.
895 */
896 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
897 (sigprop(sig) & SIGPROP_IGNORE &&
898 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
899 /* never to be seen again */
900 sigqueue_delete_proc(p, sig);
901 if (sig != SIGCONT)
902 /* easier in psignal */
903 SIGADDSET(ps->ps_sigignore, sig);
904 SIGDELSET(ps->ps_sigcatch, sig);
905 } else {
906 SIGDELSET(ps->ps_sigignore, sig);
907 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
908 SIGDELSET(ps->ps_sigcatch, sig);
909 else
910 SIGADDSET(ps->ps_sigcatch, sig);
911 }
912 #ifdef COMPAT_FREEBSD4
913 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
914 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
915 (flags & KSA_FREEBSD4) == 0)
916 SIGDELSET(ps->ps_freebsd4, sig);
917 else
918 SIGADDSET(ps->ps_freebsd4, sig);
919 #endif
920 #ifdef COMPAT_43
921 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
922 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
923 (flags & KSA_OSIGSET) == 0)
924 SIGDELSET(ps->ps_osigset, sig);
925 else
926 SIGADDSET(ps->ps_osigset, sig);
927 #endif
928 }
929 mtx_unlock(&ps->ps_mtx);
930 PROC_UNLOCK(p);
931 return (0);
932 }
933
934 #ifndef _SYS_SYSPROTO_H_
935 struct sigaction_args {
936 int sig;
937 struct sigaction *act;
938 struct sigaction *oact;
939 };
940 #endif
941 int
sys_sigaction(struct thread * td,struct sigaction_args * uap)942 sys_sigaction(struct thread *td, struct sigaction_args *uap)
943 {
944 struct sigaction act, oact;
945 struct sigaction *actp, *oactp;
946 int error;
947
948 actp = (uap->act != NULL) ? &act : NULL;
949 oactp = (uap->oact != NULL) ? &oact : NULL;
950 if (actp) {
951 error = copyin(uap->act, actp, sizeof(act));
952 if (error)
953 return (error);
954 }
955 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
956 if (oactp && !error)
957 error = copyout(oactp, uap->oact, sizeof(oact));
958 return (error);
959 }
960
961 #ifdef COMPAT_FREEBSD4
962 #ifndef _SYS_SYSPROTO_H_
963 struct freebsd4_sigaction_args {
964 int sig;
965 struct sigaction *act;
966 struct sigaction *oact;
967 };
968 #endif
969 int
freebsd4_sigaction(struct thread * td,struct freebsd4_sigaction_args * uap)970 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
971 {
972 struct sigaction act, oact;
973 struct sigaction *actp, *oactp;
974 int error;
975
976 actp = (uap->act != NULL) ? &act : NULL;
977 oactp = (uap->oact != NULL) ? &oact : NULL;
978 if (actp) {
979 error = copyin(uap->act, actp, sizeof(act));
980 if (error)
981 return (error);
982 }
983 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
984 if (oactp && !error)
985 error = copyout(oactp, uap->oact, sizeof(oact));
986 return (error);
987 }
988 #endif /* COMAPT_FREEBSD4 */
989
990 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
991 #ifndef _SYS_SYSPROTO_H_
992 struct osigaction_args {
993 int signum;
994 struct osigaction *nsa;
995 struct osigaction *osa;
996 };
997 #endif
998 int
osigaction(struct thread * td,struct osigaction_args * uap)999 osigaction(struct thread *td, struct osigaction_args *uap)
1000 {
1001 struct osigaction sa;
1002 struct sigaction nsa, osa;
1003 struct sigaction *nsap, *osap;
1004 int error;
1005
1006 if (uap->signum <= 0 || uap->signum >= ONSIG)
1007 return (EINVAL);
1008
1009 nsap = (uap->nsa != NULL) ? &nsa : NULL;
1010 osap = (uap->osa != NULL) ? &osa : NULL;
1011
1012 if (nsap) {
1013 error = copyin(uap->nsa, &sa, sizeof(sa));
1014 if (error)
1015 return (error);
1016 nsap->sa_handler = sa.sa_handler;
1017 nsap->sa_flags = sa.sa_flags;
1018 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
1019 }
1020 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1021 if (osap && !error) {
1022 sa.sa_handler = osap->sa_handler;
1023 sa.sa_flags = osap->sa_flags;
1024 SIG2OSIG(osap->sa_mask, sa.sa_mask);
1025 error = copyout(&sa, uap->osa, sizeof(sa));
1026 }
1027 return (error);
1028 }
1029
1030 #if !defined(__i386__)
1031 /* Avoid replicating the same stub everywhere */
1032 int
osigreturn(struct thread * td,struct osigreturn_args * uap)1033 osigreturn(struct thread *td, struct osigreturn_args *uap)
1034 {
1035 return (kern_nosys(td, 0));
1036 }
1037 #endif
1038 #endif /* COMPAT_43 */
1039
1040 /*
1041 * Initialize signal state for process 0;
1042 * set to ignore signals that are ignored by default.
1043 */
1044 void
siginit(struct proc * p)1045 siginit(struct proc *p)
1046 {
1047 int i;
1048 struct sigacts *ps;
1049
1050 PROC_LOCK(p);
1051 ps = p->p_sigacts;
1052 mtx_lock(&ps->ps_mtx);
1053 for (i = 1; i <= NSIG; i++) {
1054 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) {
1055 SIGADDSET(ps->ps_sigignore, i);
1056 }
1057 }
1058 mtx_unlock(&ps->ps_mtx);
1059 PROC_UNLOCK(p);
1060 }
1061
1062 /*
1063 * Reset specified signal to the default disposition.
1064 */
1065 static void
sigdflt(struct sigacts * ps,int sig)1066 sigdflt(struct sigacts *ps, int sig)
1067 {
1068
1069 mtx_assert(&ps->ps_mtx, MA_OWNED);
1070 SIGDELSET(ps->ps_sigcatch, sig);
1071 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT)
1072 SIGADDSET(ps->ps_sigignore, sig);
1073 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1074 SIGDELSET(ps->ps_siginfo, sig);
1075 }
1076
1077 /*
1078 * Reset signals for an exec of the specified process.
1079 */
1080 void
execsigs(struct proc * p)1081 execsigs(struct proc *p)
1082 {
1083 struct sigacts *ps;
1084 struct thread *td;
1085
1086 /*
1087 * Reset caught signals. Held signals remain held
1088 * through td_sigmask (unless they were caught,
1089 * and are now ignored by default).
1090 */
1091 PROC_LOCK_ASSERT(p, MA_OWNED);
1092 ps = p->p_sigacts;
1093 mtx_lock(&ps->ps_mtx);
1094 sig_drop_caught(p);
1095
1096 /*
1097 * Reset stack state to the user stack.
1098 * Clear set of signals caught on the signal stack.
1099 */
1100 td = curthread;
1101 MPASS(td->td_proc == p);
1102 td->td_sigstk.ss_flags = SS_DISABLE;
1103 td->td_sigstk.ss_size = 0;
1104 td->td_sigstk.ss_sp = 0;
1105 td->td_pflags &= ~TDP_ALTSTACK;
1106 /*
1107 * Reset no zombies if child dies flag as Solaris does.
1108 */
1109 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1110 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1111 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1112 mtx_unlock(&ps->ps_mtx);
1113 }
1114
1115 /*
1116 * kern_sigprocmask()
1117 *
1118 * Manipulate signal mask.
1119 */
1120 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)1121 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1122 int flags)
1123 {
1124 sigset_t new_block, oset1;
1125 struct proc *p;
1126 int error;
1127
1128 p = td->td_proc;
1129 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1130 PROC_LOCK_ASSERT(p, MA_OWNED);
1131 else
1132 PROC_LOCK(p);
1133 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1134 ? MA_OWNED : MA_NOTOWNED);
1135 if (oset != NULL)
1136 *oset = td->td_sigmask;
1137
1138 error = 0;
1139 if (set != NULL) {
1140 switch (how) {
1141 case SIG_BLOCK:
1142 SIG_CANTMASK(*set);
1143 oset1 = td->td_sigmask;
1144 SIGSETOR(td->td_sigmask, *set);
1145 new_block = td->td_sigmask;
1146 SIGSETNAND(new_block, oset1);
1147 break;
1148 case SIG_UNBLOCK:
1149 SIGSETNAND(td->td_sigmask, *set);
1150 signotify(td);
1151 goto out;
1152 case SIG_SETMASK:
1153 SIG_CANTMASK(*set);
1154 oset1 = td->td_sigmask;
1155 if (flags & SIGPROCMASK_OLD)
1156 SIGSETLO(td->td_sigmask, *set);
1157 else
1158 td->td_sigmask = *set;
1159 new_block = td->td_sigmask;
1160 SIGSETNAND(new_block, oset1);
1161 signotify(td);
1162 break;
1163 default:
1164 error = EINVAL;
1165 goto out;
1166 }
1167
1168 /*
1169 * The new_block set contains signals that were not previously
1170 * blocked, but are blocked now.
1171 *
1172 * In case we block any signal that was not previously blocked
1173 * for td, and process has the signal pending, try to schedule
1174 * signal delivery to some thread that does not block the
1175 * signal, possibly waking it up.
1176 */
1177 if (p->p_numthreads != 1)
1178 reschedule_signals(p, new_block, flags);
1179 }
1180
1181 out:
1182 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1183 PROC_UNLOCK(p);
1184 return (error);
1185 }
1186
1187 #ifndef _SYS_SYSPROTO_H_
1188 struct sigprocmask_args {
1189 int how;
1190 const sigset_t *set;
1191 sigset_t *oset;
1192 };
1193 #endif
1194 int
sys_sigprocmask(struct thread * td,struct sigprocmask_args * uap)1195 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
1196 {
1197 sigset_t set, oset;
1198 sigset_t *setp, *osetp;
1199 int error;
1200
1201 setp = (uap->set != NULL) ? &set : NULL;
1202 osetp = (uap->oset != NULL) ? &oset : NULL;
1203 if (setp) {
1204 error = copyin(uap->set, setp, sizeof(set));
1205 if (error)
1206 return (error);
1207 }
1208 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1209 if (osetp && !error) {
1210 error = copyout(osetp, uap->oset, sizeof(oset));
1211 }
1212 return (error);
1213 }
1214
1215 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1216 #ifndef _SYS_SYSPROTO_H_
1217 struct osigprocmask_args {
1218 int how;
1219 osigset_t mask;
1220 };
1221 #endif
1222 int
osigprocmask(struct thread * td,struct osigprocmask_args * uap)1223 osigprocmask(struct thread *td, struct osigprocmask_args *uap)
1224 {
1225 sigset_t set, oset;
1226 int error;
1227
1228 OSIG2SIG(uap->mask, set);
1229 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1230 SIG2OSIG(oset, td->td_retval[0]);
1231 return (error);
1232 }
1233 #endif /* COMPAT_43 */
1234
1235 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1236 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1237 {
1238 ksiginfo_t ksi;
1239 sigset_t set;
1240 int error;
1241
1242 error = copyin(uap->set, &set, sizeof(set));
1243 if (error) {
1244 td->td_retval[0] = error;
1245 return (0);
1246 }
1247
1248 error = kern_sigtimedwait(td, set, &ksi, NULL);
1249 if (error) {
1250 /*
1251 * sigwait() function shall not return EINTR, but
1252 * the syscall does. Non-ancient libc provides the
1253 * wrapper which hides EINTR. Otherwise, EINTR return
1254 * is used by libthr to handle required cancellation
1255 * point in the sigwait().
1256 */
1257 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1258 return (ERESTART);
1259 td->td_retval[0] = error;
1260 return (0);
1261 }
1262
1263 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1264 td->td_retval[0] = error;
1265 return (0);
1266 }
1267
1268 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1269 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1270 {
1271 struct timespec ts;
1272 struct timespec *timeout;
1273 sigset_t set;
1274 ksiginfo_t ksi;
1275 int error;
1276
1277 if (uap->timeout) {
1278 error = copyin(uap->timeout, &ts, sizeof(ts));
1279 if (error)
1280 return (error);
1281
1282 timeout = &ts;
1283 } else
1284 timeout = NULL;
1285
1286 error = copyin(uap->set, &set, sizeof(set));
1287 if (error)
1288 return (error);
1289
1290 error = kern_sigtimedwait(td, set, &ksi, timeout);
1291 if (error)
1292 return (error);
1293
1294 if (uap->info)
1295 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1296
1297 if (error == 0)
1298 td->td_retval[0] = ksi.ksi_signo;
1299 return (error);
1300 }
1301
1302 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1303 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1304 {
1305 ksiginfo_t ksi;
1306 sigset_t set;
1307 int error;
1308
1309 error = copyin(uap->set, &set, sizeof(set));
1310 if (error)
1311 return (error);
1312
1313 error = kern_sigtimedwait(td, set, &ksi, NULL);
1314 if (error)
1315 return (error);
1316
1317 if (uap->info)
1318 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1319
1320 if (error == 0)
1321 td->td_retval[0] = ksi.ksi_signo;
1322 return (error);
1323 }
1324
1325 static void
proc_td_siginfo_capture(struct thread * td,siginfo_t * si)1326 proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
1327 {
1328 struct thread *thr;
1329
1330 FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
1331 if (thr == td)
1332 thr->td_si = *si;
1333 else
1334 thr->td_si.si_signo = 0;
1335 }
1336 }
1337
1338 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1339 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1340 struct timespec *timeout)
1341 {
1342 struct sigacts *ps;
1343 sigset_t saved_mask, new_block;
1344 struct proc *p;
1345 int error, sig, timevalid = 0;
1346 sbintime_t sbt, precision, tsbt;
1347 struct timespec ts;
1348 bool traced;
1349
1350 p = td->td_proc;
1351 error = 0;
1352 traced = false;
1353
1354 /* Ensure the sigfastblock value is up to date. */
1355 sigfastblock_fetch(td);
1356
1357 if (timeout != NULL) {
1358 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1359 timevalid = 1;
1360 ts = *timeout;
1361 if (ts.tv_sec < INT32_MAX / 2) {
1362 tsbt = tstosbt(ts);
1363 precision = tsbt;
1364 precision >>= tc_precexp;
1365 if (TIMESEL(&sbt, tsbt))
1366 sbt += tc_tick_sbt;
1367 sbt += tsbt;
1368 } else
1369 precision = sbt = 0;
1370 }
1371 } else
1372 precision = sbt = 0;
1373 ksiginfo_init(ksi);
1374 /* Some signals can not be waited for. */
1375 SIG_CANTMASK(waitset);
1376 ps = p->p_sigacts;
1377 PROC_LOCK(p);
1378 saved_mask = td->td_sigmask;
1379 SIGSETNAND(td->td_sigmask, waitset);
1380 if ((p->p_sysent->sv_flags & SV_SIG_DISCIGN) != 0 ||
1381 !kern_sig_discard_ign) {
1382 thread_lock(td);
1383 td->td_flags |= TDF_SIGWAIT;
1384 thread_unlock(td);
1385 }
1386 for (;;) {
1387 mtx_lock(&ps->ps_mtx);
1388 sig = cursig(td);
1389 mtx_unlock(&ps->ps_mtx);
1390 KASSERT(sig >= 0, ("sig %d", sig));
1391 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1392 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1393 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1394 error = 0;
1395 break;
1396 }
1397 }
1398
1399 if (error != 0)
1400 break;
1401
1402 /*
1403 * POSIX says this must be checked after looking for pending
1404 * signals.
1405 */
1406 if (timeout != NULL && !timevalid) {
1407 error = EINVAL;
1408 break;
1409 }
1410
1411 if (traced) {
1412 error = EINTR;
1413 break;
1414 }
1415
1416 error = msleep_sbt(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH,
1417 "sigwait", sbt, precision, C_ABSOLUTE);
1418
1419 /* The syscalls can not be restarted. */
1420 if (error == ERESTART)
1421 error = EINTR;
1422
1423 /*
1424 * If PTRACE_SCE or PTRACE_SCX were set after
1425 * userspace entered the syscall, return spurious
1426 * EINTR after wait was done. Only do this as last
1427 * resort after rechecking for possible queued signals
1428 * and expired timeouts.
1429 */
1430 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0)
1431 traced = true;
1432 }
1433 thread_lock(td);
1434 td->td_flags &= ~TDF_SIGWAIT;
1435 thread_unlock(td);
1436
1437 new_block = saved_mask;
1438 SIGSETNAND(new_block, td->td_sigmask);
1439 td->td_sigmask = saved_mask;
1440 /*
1441 * Fewer signals can be delivered to us, reschedule signal
1442 * notification.
1443 */
1444 if (p->p_numthreads != 1)
1445 reschedule_signals(p, new_block, 0);
1446
1447 if (error == 0) {
1448 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1449
1450 if (ksi->ksi_code == SI_TIMER)
1451 itimer_accept(p, ksi->ksi_timerid, ksi);
1452
1453 #ifdef KTRACE
1454 if (KTRPOINT(td, KTR_PSIG)) {
1455 sig_t action;
1456
1457 mtx_lock(&ps->ps_mtx);
1458 action = ps->ps_sigact[_SIG_IDX(sig)];
1459 mtx_unlock(&ps->ps_mtx);
1460 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1461 }
1462 #endif
1463 if (sig == SIGKILL) {
1464 proc_td_siginfo_capture(td, &ksi->ksi_info);
1465 sigexit(td, sig);
1466 }
1467 }
1468 PROC_UNLOCK(p);
1469 return (error);
1470 }
1471
1472 #ifndef _SYS_SYSPROTO_H_
1473 struct sigpending_args {
1474 sigset_t *set;
1475 };
1476 #endif
1477 int
sys_sigpending(struct thread * td,struct sigpending_args * uap)1478 sys_sigpending(struct thread *td, struct sigpending_args *uap)
1479 {
1480 struct proc *p = td->td_proc;
1481 sigset_t pending;
1482
1483 PROC_LOCK(p);
1484 pending = p->p_sigqueue.sq_signals;
1485 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1486 PROC_UNLOCK(p);
1487 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1488 }
1489
1490 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1491 #ifndef _SYS_SYSPROTO_H_
1492 struct osigpending_args {
1493 int dummy;
1494 };
1495 #endif
1496 int
osigpending(struct thread * td,struct osigpending_args * uap)1497 osigpending(struct thread *td, struct osigpending_args *uap)
1498 {
1499 struct proc *p = td->td_proc;
1500 sigset_t pending;
1501
1502 PROC_LOCK(p);
1503 pending = p->p_sigqueue.sq_signals;
1504 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1505 PROC_UNLOCK(p);
1506 SIG2OSIG(pending, td->td_retval[0]);
1507 return (0);
1508 }
1509 #endif /* COMPAT_43 */
1510
1511 #if defined(COMPAT_43)
1512 /*
1513 * Generalized interface signal handler, 4.3-compatible.
1514 */
1515 #ifndef _SYS_SYSPROTO_H_
1516 struct osigvec_args {
1517 int signum;
1518 struct sigvec *nsv;
1519 struct sigvec *osv;
1520 };
1521 #endif
1522 /* ARGSUSED */
1523 int
osigvec(struct thread * td,struct osigvec_args * uap)1524 osigvec(struct thread *td, struct osigvec_args *uap)
1525 {
1526 struct sigvec vec;
1527 struct sigaction nsa, osa;
1528 struct sigaction *nsap, *osap;
1529 int error;
1530
1531 if (uap->signum <= 0 || uap->signum >= ONSIG)
1532 return (EINVAL);
1533 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1534 osap = (uap->osv != NULL) ? &osa : NULL;
1535 if (nsap) {
1536 error = copyin(uap->nsv, &vec, sizeof(vec));
1537 if (error)
1538 return (error);
1539 nsap->sa_handler = vec.sv_handler;
1540 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1541 nsap->sa_flags = vec.sv_flags;
1542 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1543 }
1544 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1545 if (osap && !error) {
1546 vec.sv_handler = osap->sa_handler;
1547 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1548 vec.sv_flags = osap->sa_flags;
1549 vec.sv_flags &= ~SA_NOCLDWAIT;
1550 vec.sv_flags ^= SA_RESTART;
1551 error = copyout(&vec, uap->osv, sizeof(vec));
1552 }
1553 return (error);
1554 }
1555
1556 #ifndef _SYS_SYSPROTO_H_
1557 struct osigblock_args {
1558 int mask;
1559 };
1560 #endif
1561 int
osigblock(struct thread * td,struct osigblock_args * uap)1562 osigblock(struct thread *td, struct osigblock_args *uap)
1563 {
1564 sigset_t set, oset;
1565
1566 OSIG2SIG(uap->mask, set);
1567 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1568 SIG2OSIG(oset, td->td_retval[0]);
1569 return (0);
1570 }
1571
1572 #ifndef _SYS_SYSPROTO_H_
1573 struct osigsetmask_args {
1574 int mask;
1575 };
1576 #endif
1577 int
osigsetmask(struct thread * td,struct osigsetmask_args * uap)1578 osigsetmask(struct thread *td, struct osigsetmask_args *uap)
1579 {
1580 sigset_t set, oset;
1581
1582 OSIG2SIG(uap->mask, set);
1583 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1584 SIG2OSIG(oset, td->td_retval[0]);
1585 return (0);
1586 }
1587 #endif /* COMPAT_43 */
1588
1589 /*
1590 * Suspend calling thread until signal, providing mask to be set in the
1591 * meantime.
1592 */
1593 #ifndef _SYS_SYSPROTO_H_
1594 struct sigsuspend_args {
1595 const sigset_t *sigmask;
1596 };
1597 #endif
1598 /* ARGSUSED */
1599 int
sys_sigsuspend(struct thread * td,struct sigsuspend_args * uap)1600 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
1601 {
1602 sigset_t mask;
1603 int error;
1604
1605 error = copyin(uap->sigmask, &mask, sizeof(mask));
1606 if (error)
1607 return (error);
1608 return (kern_sigsuspend(td, mask));
1609 }
1610
1611 int
kern_sigsuspend(struct thread * td,sigset_t mask)1612 kern_sigsuspend(struct thread *td, sigset_t mask)
1613 {
1614 struct proc *p = td->td_proc;
1615 int has_sig, sig;
1616
1617 /* Ensure the sigfastblock value is up to date. */
1618 sigfastblock_fetch(td);
1619
1620 /*
1621 * When returning from sigsuspend, we want
1622 * the old mask to be restored after the
1623 * signal handler has finished. Thus, we
1624 * save it here and mark the sigacts structure
1625 * to indicate this.
1626 */
1627 PROC_LOCK(p);
1628 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1629 SIGPROCMASK_PROC_LOCKED);
1630 td->td_pflags |= TDP_OLDMASK;
1631 ast_sched(td, TDA_SIGSUSPEND);
1632
1633 /*
1634 * Process signals now. Otherwise, we can get spurious wakeup
1635 * due to signal entered process queue, but delivered to other
1636 * thread. But sigsuspend should return only on signal
1637 * delivery.
1638 */
1639 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1640 for (has_sig = 0; !has_sig;) {
1641 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH,
1642 "sigsusp", 0) == 0)
1643 /* void */;
1644 thread_suspend_check(0);
1645 mtx_lock(&p->p_sigacts->ps_mtx);
1646 while ((sig = cursig(td)) != 0) {
1647 KASSERT(sig >= 0, ("sig %d", sig));
1648 has_sig += postsig(sig);
1649 }
1650 mtx_unlock(&p->p_sigacts->ps_mtx);
1651
1652 /*
1653 * If PTRACE_SCE or PTRACE_SCX were set after
1654 * userspace entered the syscall, return spurious
1655 * EINTR.
1656 */
1657 if ((p->p_ptevents & PTRACE_SYSCALL) != 0)
1658 has_sig += 1;
1659 }
1660 PROC_UNLOCK(p);
1661 td->td_errno = EINTR;
1662 td->td_pflags |= TDP_NERRNO;
1663 return (EJUSTRETURN);
1664 }
1665
1666 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1667 /*
1668 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1669 * convention: libc stub passes mask, not pointer, to save a copyin.
1670 */
1671 #ifndef _SYS_SYSPROTO_H_
1672 struct osigsuspend_args {
1673 osigset_t mask;
1674 };
1675 #endif
1676 /* ARGSUSED */
1677 int
osigsuspend(struct thread * td,struct osigsuspend_args * uap)1678 osigsuspend(struct thread *td, struct osigsuspend_args *uap)
1679 {
1680 sigset_t mask;
1681
1682 OSIG2SIG(uap->mask, mask);
1683 return (kern_sigsuspend(td, mask));
1684 }
1685 #endif /* COMPAT_43 */
1686
1687 #if defined(COMPAT_43)
1688 #ifndef _SYS_SYSPROTO_H_
1689 struct osigstack_args {
1690 struct sigstack *nss;
1691 struct sigstack *oss;
1692 };
1693 #endif
1694 /* ARGSUSED */
1695 int
osigstack(struct thread * td,struct osigstack_args * uap)1696 osigstack(struct thread *td, struct osigstack_args *uap)
1697 {
1698 struct sigstack nss, oss;
1699 int error = 0;
1700
1701 if (uap->nss != NULL) {
1702 error = copyin(uap->nss, &nss, sizeof(nss));
1703 if (error)
1704 return (error);
1705 }
1706 oss.ss_sp = td->td_sigstk.ss_sp;
1707 oss.ss_onstack = sigonstack(cpu_getstack(td));
1708 if (uap->nss != NULL) {
1709 td->td_sigstk.ss_sp = nss.ss_sp;
1710 td->td_sigstk.ss_size = 0;
1711 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1712 td->td_pflags |= TDP_ALTSTACK;
1713 }
1714 if (uap->oss != NULL)
1715 error = copyout(&oss, uap->oss, sizeof(oss));
1716
1717 return (error);
1718 }
1719 #endif /* COMPAT_43 */
1720
1721 #ifndef _SYS_SYSPROTO_H_
1722 struct sigaltstack_args {
1723 stack_t *ss;
1724 stack_t *oss;
1725 };
1726 #endif
1727 /* ARGSUSED */
1728 int
sys_sigaltstack(struct thread * td,struct sigaltstack_args * uap)1729 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
1730 {
1731 stack_t ss, oss;
1732 int error;
1733
1734 if (uap->ss != NULL) {
1735 error = copyin(uap->ss, &ss, sizeof(ss));
1736 if (error)
1737 return (error);
1738 }
1739 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1740 (uap->oss != NULL) ? &oss : NULL);
1741 if (error)
1742 return (error);
1743 if (uap->oss != NULL)
1744 error = copyout(&oss, uap->oss, sizeof(stack_t));
1745 return (error);
1746 }
1747
1748 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1749 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1750 {
1751 struct proc *p = td->td_proc;
1752 int oonstack;
1753
1754 oonstack = sigonstack(cpu_getstack(td));
1755
1756 if (oss != NULL) {
1757 *oss = td->td_sigstk;
1758 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1759 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1760 }
1761
1762 if (ss != NULL) {
1763 if (oonstack)
1764 return (EPERM);
1765 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1766 return (EINVAL);
1767 if (!(ss->ss_flags & SS_DISABLE)) {
1768 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1769 return (ENOMEM);
1770
1771 td->td_sigstk = *ss;
1772 td->td_pflags |= TDP_ALTSTACK;
1773 } else {
1774 td->td_pflags &= ~TDP_ALTSTACK;
1775 }
1776 }
1777 return (0);
1778 }
1779
1780 struct killpg1_ctx {
1781 struct thread *td;
1782 ksiginfo_t *ksi;
1783 int sig;
1784 bool sent;
1785 bool found;
1786 int ret;
1787 };
1788
1789 static void
killpg1_sendsig_locked(struct proc * p,struct killpg1_ctx * arg)1790 killpg1_sendsig_locked(struct proc *p, struct killpg1_ctx *arg)
1791 {
1792 int err;
1793
1794 err = p_cansignal(arg->td, p, arg->sig);
1795 if (err == 0 && arg->sig != 0)
1796 pksignal(p, arg->sig, arg->ksi);
1797 if (err != ESRCH)
1798 arg->found = true;
1799 if (err == 0)
1800 arg->sent = true;
1801 else if (arg->ret == 0 && err != ESRCH && err != EPERM)
1802 arg->ret = err;
1803 }
1804
1805 static void
killpg1_sendsig(struct proc * p,bool notself,struct killpg1_ctx * arg)1806 killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg)
1807 {
1808
1809 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 ||
1810 (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW)
1811 return;
1812
1813 PROC_LOCK(p);
1814 killpg1_sendsig_locked(p, arg);
1815 PROC_UNLOCK(p);
1816 }
1817
1818 static void
kill_processes_prison_cb(struct proc * p,void * arg)1819 kill_processes_prison_cb(struct proc *p, void *arg)
1820 {
1821 struct killpg1_ctx *ctx = arg;
1822
1823 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 ||
1824 (p == ctx->td->td_proc) || p->p_state == PRS_NEW)
1825 return;
1826
1827 killpg1_sendsig_locked(p, ctx);
1828 }
1829
1830 /*
1831 * Common code for kill process group/broadcast kill.
1832 * td is the calling thread, as usual.
1833 */
1834 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1835 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1836 {
1837 struct proc *p;
1838 struct pgrp *pgrp;
1839 struct killpg1_ctx arg;
1840
1841 arg.td = td;
1842 arg.ksi = ksi;
1843 arg.sig = sig;
1844 arg.sent = false;
1845 arg.found = false;
1846 arg.ret = 0;
1847 if (all) {
1848 /*
1849 * broadcast
1850 */
1851 prison_proc_iterate(td->td_ucred->cr_prison,
1852 kill_processes_prison_cb, &arg);
1853 } else {
1854 again:
1855 sx_slock(&proctree_lock);
1856 if (pgid == 0) {
1857 /*
1858 * zero pgid means send to my process group.
1859 */
1860 pgrp = td->td_proc->p_pgrp;
1861 PGRP_LOCK(pgrp);
1862 } else {
1863 pgrp = pgfind(pgid);
1864 if (pgrp == NULL) {
1865 sx_sunlock(&proctree_lock);
1866 return (ESRCH);
1867 }
1868 }
1869 sx_sunlock(&proctree_lock);
1870 if (!sx_try_xlock(&pgrp->pg_killsx)) {
1871 PGRP_UNLOCK(pgrp);
1872 sx_xlock(&pgrp->pg_killsx);
1873 sx_xunlock(&pgrp->pg_killsx);
1874 goto again;
1875 }
1876 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1877 killpg1_sendsig(p, false, &arg);
1878 }
1879 PGRP_UNLOCK(pgrp);
1880 sx_xunlock(&pgrp->pg_killsx);
1881 }
1882 MPASS(arg.ret != 0 || arg.found || !arg.sent);
1883 if (arg.ret == 0 && !arg.sent)
1884 arg.ret = arg.found ? EPERM : ESRCH;
1885 return (arg.ret);
1886 }
1887
1888 #ifndef _SYS_SYSPROTO_H_
1889 struct kill_args {
1890 int pid;
1891 int signum;
1892 };
1893 #endif
1894 /* ARGSUSED */
1895 int
sys_kill(struct thread * td,struct kill_args * uap)1896 sys_kill(struct thread *td, struct kill_args *uap)
1897 {
1898
1899 return (kern_kill(td, uap->pid, uap->signum));
1900 }
1901
1902 int
kern_kill(struct thread * td,pid_t pid,int signum)1903 kern_kill(struct thread *td, pid_t pid, int signum)
1904 {
1905 ksiginfo_t ksi;
1906 struct proc *p;
1907 int error;
1908
1909 /*
1910 * A process in capability mode can send signals only to himself.
1911 * The main rationale behind this is that abort(3) is implemented as
1912 * kill(getpid(), SIGABRT).
1913 */
1914 if (pid != td->td_proc->p_pid) {
1915 if (CAP_TRACING(td))
1916 ktrcapfail(CAPFAIL_SIGNAL, &signum);
1917 if (IN_CAPABILITY_MODE(td))
1918 return (ECAPMODE);
1919 }
1920
1921 AUDIT_ARG_SIGNUM(signum);
1922 AUDIT_ARG_PID(pid);
1923 if ((u_int)signum > _SIG_MAXSIG)
1924 return (EINVAL);
1925
1926 ksiginfo_init(&ksi);
1927 ksi.ksi_signo = signum;
1928 ksi.ksi_code = SI_USER;
1929 ksi.ksi_pid = td->td_proc->p_pid;
1930 ksi.ksi_uid = td->td_ucred->cr_ruid;
1931
1932 if (pid > 0) {
1933 /* kill single process */
1934 if ((p = pfind_any(pid)) == NULL)
1935 return (ESRCH);
1936 AUDIT_ARG_PROCESS(p);
1937 error = p_cansignal(td, p, signum);
1938 if (error == 0 && signum)
1939 pksignal(p, signum, &ksi);
1940 PROC_UNLOCK(p);
1941 return (error);
1942 }
1943 switch (pid) {
1944 case -1: /* broadcast signal */
1945 return (killpg1(td, signum, 0, 1, &ksi));
1946 case 0: /* signal own process group */
1947 return (killpg1(td, signum, 0, 0, &ksi));
1948 default: /* negative explicit process group */
1949 return (killpg1(td, signum, -pid, 0, &ksi));
1950 }
1951 /* NOTREACHED */
1952 }
1953
1954 int
sys_pdkill(struct thread * td,struct pdkill_args * uap)1955 sys_pdkill(struct thread *td, struct pdkill_args *uap)
1956 {
1957 struct proc *p;
1958 int error;
1959
1960 AUDIT_ARG_SIGNUM(uap->signum);
1961 AUDIT_ARG_FD(uap->fd);
1962 if ((u_int)uap->signum > _SIG_MAXSIG)
1963 return (EINVAL);
1964
1965 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p);
1966 if (error)
1967 return (error);
1968 AUDIT_ARG_PROCESS(p);
1969 error = p_cansignal(td, p, uap->signum);
1970 if (error == 0 && uap->signum)
1971 kern_psignal(p, uap->signum);
1972 PROC_UNLOCK(p);
1973 return (error);
1974 }
1975
1976 #if defined(COMPAT_43)
1977 #ifndef _SYS_SYSPROTO_H_
1978 struct okillpg_args {
1979 int pgid;
1980 int signum;
1981 };
1982 #endif
1983 /* ARGSUSED */
1984 int
okillpg(struct thread * td,struct okillpg_args * uap)1985 okillpg(struct thread *td, struct okillpg_args *uap)
1986 {
1987 ksiginfo_t ksi;
1988
1989 AUDIT_ARG_SIGNUM(uap->signum);
1990 AUDIT_ARG_PID(uap->pgid);
1991 if ((u_int)uap->signum > _SIG_MAXSIG)
1992 return (EINVAL);
1993
1994 ksiginfo_init(&ksi);
1995 ksi.ksi_signo = uap->signum;
1996 ksi.ksi_code = SI_USER;
1997 ksi.ksi_pid = td->td_proc->p_pid;
1998 ksi.ksi_uid = td->td_ucred->cr_ruid;
1999 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
2000 }
2001 #endif /* COMPAT_43 */
2002
2003 #ifndef _SYS_SYSPROTO_H_
2004 struct sigqueue_args {
2005 pid_t pid;
2006 int signum;
2007 /* union sigval */ void *value;
2008 };
2009 #endif
2010 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)2011 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
2012 {
2013 union sigval sv;
2014
2015 sv.sival_ptr = uap->value;
2016
2017 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
2018 }
2019
2020 int
kern_sigqueue(struct thread * td,pid_t pid,int signumf,union sigval * value)2021 kern_sigqueue(struct thread *td, pid_t pid, int signumf, union sigval *value)
2022 {
2023 ksiginfo_t ksi;
2024 struct proc *p;
2025 struct thread *td2;
2026 u_int signum;
2027 int error;
2028
2029 signum = signumf & ~__SIGQUEUE_TID;
2030 if (signum > _SIG_MAXSIG)
2031 return (EINVAL);
2032
2033 /*
2034 * Specification says sigqueue can only send signal to
2035 * single process.
2036 */
2037 if (pid <= 0)
2038 return (EINVAL);
2039
2040 if ((signumf & __SIGQUEUE_TID) == 0) {
2041 if ((p = pfind_any(pid)) == NULL)
2042 return (ESRCH);
2043 td2 = NULL;
2044 } else {
2045 p = td->td_proc;
2046 td2 = tdfind((lwpid_t)pid, p->p_pid);
2047 if (td2 == NULL)
2048 return (ESRCH);
2049 }
2050
2051 error = p_cansignal(td, p, signum);
2052 if (error == 0 && signum != 0) {
2053 ksiginfo_init(&ksi);
2054 ksi.ksi_flags = KSI_SIGQ;
2055 ksi.ksi_signo = signum;
2056 ksi.ksi_code = SI_QUEUE;
2057 ksi.ksi_pid = td->td_proc->p_pid;
2058 ksi.ksi_uid = td->td_ucred->cr_ruid;
2059 ksi.ksi_value = *value;
2060 error = tdsendsignal(p, td2, ksi.ksi_signo, &ksi);
2061 }
2062 PROC_UNLOCK(p);
2063 return (error);
2064 }
2065
2066 /*
2067 * Send a signal to a process group. If checktty is 1,
2068 * limit to members which have a controlling terminal.
2069 */
2070 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)2071 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
2072 {
2073 struct proc *p;
2074
2075 if (pgrp) {
2076 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
2077 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
2078 PROC_LOCK(p);
2079 if (p->p_state == PRS_NORMAL &&
2080 (checkctty == 0 || p->p_flag & P_CONTROLT))
2081 pksignal(p, sig, ksi);
2082 PROC_UNLOCK(p);
2083 }
2084 }
2085 }
2086
2087 /*
2088 * Recalculate the signal mask and reset the signal disposition after
2089 * usermode frame for delivery is formed. Should be called after
2090 * mach-specific routine, because sysent->sv_sendsig() needs correct
2091 * ps_siginfo and signal mask.
2092 */
2093 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)2094 postsig_done(int sig, struct thread *td, struct sigacts *ps)
2095 {
2096 sigset_t mask;
2097
2098 mtx_assert(&ps->ps_mtx, MA_OWNED);
2099 td->td_ru.ru_nsignals++;
2100 mask = ps->ps_catchmask[_SIG_IDX(sig)];
2101 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2102 SIGADDSET(mask, sig);
2103 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
2104 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
2105 if (SIGISMEMBER(ps->ps_sigreset, sig))
2106 sigdflt(ps, sig);
2107 }
2108
2109 /*
2110 * Send a signal caused by a trap to the current thread. If it will be
2111 * caught immediately, deliver it with correct code. Otherwise, post it
2112 * normally.
2113 */
2114 void
trapsignal(struct thread * td,ksiginfo_t * ksi)2115 trapsignal(struct thread *td, ksiginfo_t *ksi)
2116 {
2117 struct sigacts *ps;
2118 struct proc *p;
2119 sigset_t sigmask;
2120 int sig;
2121
2122 p = td->td_proc;
2123 sig = ksi->ksi_signo;
2124 KASSERT(_SIG_VALID(sig), ("invalid signal"));
2125
2126 sigfastblock_fetch(td);
2127 PROC_LOCK(p);
2128 ps = p->p_sigacts;
2129 mtx_lock(&ps->ps_mtx);
2130 sigmask = td->td_sigmask;
2131 if (td->td_sigblock_val != 0)
2132 SIGSETOR(sigmask, fastblock_mask);
2133 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
2134 !SIGISMEMBER(sigmask, sig)) {
2135 #ifdef KTRACE
2136 if (KTRPOINT(curthread, KTR_PSIG))
2137 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
2138 &td->td_sigmask, ksi->ksi_code);
2139 #endif
2140 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
2141 ksi, &td->td_sigmask);
2142 postsig_done(sig, td, ps);
2143 mtx_unlock(&ps->ps_mtx);
2144 } else {
2145 /*
2146 * Avoid a possible infinite loop if the thread
2147 * masking the signal or process is ignoring the
2148 * signal.
2149 */
2150 if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) ||
2151 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
2152 SIGDELSET(td->td_sigmask, sig);
2153 SIGDELSET(ps->ps_sigcatch, sig);
2154 SIGDELSET(ps->ps_sigignore, sig);
2155 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2156 td->td_pflags &= ~TDP_SIGFASTBLOCK;
2157 td->td_sigblock_val = 0;
2158 }
2159 mtx_unlock(&ps->ps_mtx);
2160 p->p_sig = sig; /* XXX to verify code */
2161 tdsendsignal(p, td, sig, ksi);
2162 }
2163 PROC_UNLOCK(p);
2164 }
2165
2166 static struct thread *
sigtd(struct proc * p,int sig,bool fast_sigblock)2167 sigtd(struct proc *p, int sig, bool fast_sigblock)
2168 {
2169 struct thread *td, *signal_td;
2170
2171 PROC_LOCK_ASSERT(p, MA_OWNED);
2172 MPASS(!fast_sigblock || p == curproc);
2173
2174 /*
2175 * Check if current thread can handle the signal without
2176 * switching context to another thread.
2177 */
2178 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) &&
2179 (!fast_sigblock || curthread->td_sigblock_val == 0))
2180 return (curthread);
2181
2182 /* Find a non-stopped thread that does not mask the signal. */
2183 signal_td = NULL;
2184 FOREACH_THREAD_IN_PROC(p, td) {
2185 if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock ||
2186 td != curthread || td->td_sigblock_val == 0) &&
2187 (td->td_flags & TDF_BOUNDARY) == 0) {
2188 signal_td = td;
2189 break;
2190 }
2191 }
2192 /* Select random (first) thread if no better match was found. */
2193 if (signal_td == NULL)
2194 signal_td = FIRST_THREAD_IN_PROC(p);
2195 return (signal_td);
2196 }
2197
2198 /*
2199 * Send the signal to the process. If the signal has an action, the action
2200 * is usually performed by the target process rather than the caller; we add
2201 * the signal to the set of pending signals for the process.
2202 *
2203 * Exceptions:
2204 * o When a stop signal is sent to a sleeping process that takes the
2205 * default action, the process is stopped without awakening it.
2206 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2207 * regardless of the signal action (eg, blocked or ignored).
2208 *
2209 * Other ignored signals are discarded immediately.
2210 *
2211 * NB: This function may be entered from the debugger via the "kill" DDB
2212 * command. There is little that can be done to mitigate the possibly messy
2213 * side effects of this unwise possibility.
2214 */
2215 void
kern_psignal(struct proc * p,int sig)2216 kern_psignal(struct proc *p, int sig)
2217 {
2218 ksiginfo_t ksi;
2219
2220 ksiginfo_init(&ksi);
2221 ksi.ksi_signo = sig;
2222 ksi.ksi_code = SI_KERNEL;
2223 (void) tdsendsignal(p, NULL, sig, &ksi);
2224 }
2225
2226 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)2227 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2228 {
2229
2230 return (tdsendsignal(p, NULL, sig, ksi));
2231 }
2232
2233 /* Utility function for finding a thread to send signal event to. */
2234 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)2235 sigev_findtd(struct proc *p, struct sigevent *sigev, struct thread **ttd)
2236 {
2237 struct thread *td;
2238
2239 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2240 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2241 if (td == NULL)
2242 return (ESRCH);
2243 *ttd = td;
2244 } else {
2245 *ttd = NULL;
2246 PROC_LOCK(p);
2247 }
2248 return (0);
2249 }
2250
2251 void
tdsignal(struct thread * td,int sig)2252 tdsignal(struct thread *td, int sig)
2253 {
2254 ksiginfo_t ksi;
2255
2256 ksiginfo_init(&ksi);
2257 ksi.ksi_signo = sig;
2258 ksi.ksi_code = SI_KERNEL;
2259 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2260 }
2261
2262 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2263 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2264 {
2265
2266 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2267 }
2268
2269 static void
sig_sleepq_abort(struct thread * td,int intrval)2270 sig_sleepq_abort(struct thread *td, int intrval)
2271 {
2272 THREAD_LOCK_ASSERT(td, MA_OWNED);
2273
2274 if (intrval == 0 && (td->td_flags & TDF_SIGWAIT) == 0)
2275 thread_unlock(td);
2276 else
2277 sleepq_abort(td, intrval);
2278 }
2279
2280 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2281 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2282 {
2283 sig_t action;
2284 sigqueue_t *sigqueue;
2285 struct sigacts *ps;
2286 int intrval, prop, ret;
2287
2288 MPASS(td == NULL || p == td->td_proc);
2289 PROC_LOCK_ASSERT(p, MA_OWNED);
2290
2291 if (!_SIG_VALID(sig))
2292 panic("%s(): invalid signal %d", __func__, sig);
2293
2294 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2295
2296 /*
2297 * IEEE Std 1003.1-2001: return success when killing a zombie.
2298 */
2299 if (p->p_state == PRS_ZOMBIE) {
2300 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2301 ksiginfo_tryfree(ksi);
2302 return (0);
2303 }
2304
2305 ps = p->p_sigacts;
2306 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
2307 prop = sigprop(sig);
2308
2309 if (td == NULL) {
2310 td = sigtd(p, sig, false);
2311 sigqueue = &p->p_sigqueue;
2312 } else
2313 sigqueue = &td->td_sigqueue;
2314
2315 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2316
2317 /*
2318 * If the signal is being ignored, then we forget about it
2319 * immediately, except when the target process executes
2320 * sigwait(). (Note: we don't set SIGCONT in ps_sigignore,
2321 * and if it is set to SIG_IGN, action will be SIG_DFL here.)
2322 */
2323 mtx_lock(&ps->ps_mtx);
2324 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2325 if (kern_sig_discard_ign &&
2326 (p->p_sysent->sv_flags & SV_SIG_DISCIGN) == 0) {
2327 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2328
2329 mtx_unlock(&ps->ps_mtx);
2330 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2331 ksiginfo_tryfree(ksi);
2332 return (0);
2333 } else {
2334 action = SIG_CATCH;
2335 intrval = 0;
2336 }
2337 } else {
2338 if (SIGISMEMBER(td->td_sigmask, sig))
2339 action = SIG_HOLD;
2340 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2341 action = SIG_CATCH;
2342 else
2343 action = SIG_DFL;
2344 if (SIGISMEMBER(ps->ps_sigintr, sig))
2345 intrval = EINTR;
2346 else
2347 intrval = ERESTART;
2348 }
2349 mtx_unlock(&ps->ps_mtx);
2350
2351 if (prop & SIGPROP_CONT)
2352 sigqueue_delete_stopmask_proc(p);
2353 else if (prop & SIGPROP_STOP) {
2354 if (pt_attach_transparent &&
2355 (p->p_flag & P_TRACED) != 0 &&
2356 (p->p_flag2 & P2_PTRACE_FSTP) != 0) {
2357 PROC_SLOCK(p);
2358 sig_handle_first_stop(NULL, p, sig);
2359 PROC_SUNLOCK(p);
2360 return (0);
2361 }
2362
2363 /*
2364 * If sending a tty stop signal to a member of an orphaned
2365 * process group, discard the signal here if the action
2366 * is default; don't stop the process below if sleeping,
2367 * and don't clear any pending SIGCONT.
2368 */
2369 if ((prop & SIGPROP_TTYSTOP) != 0 &&
2370 (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 &&
2371 action == SIG_DFL) {
2372 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2373 ksiginfo_tryfree(ksi);
2374 return (0);
2375 }
2376 sigqueue_delete_proc(p, SIGCONT);
2377 if (p->p_flag & P_CONTINUED) {
2378 p->p_flag &= ~P_CONTINUED;
2379 PROC_LOCK(p->p_pptr);
2380 sigqueue_take(p->p_ksi);
2381 PROC_UNLOCK(p->p_pptr);
2382 }
2383 }
2384
2385 ret = sigqueue_add(sigqueue, sig, ksi);
2386 if (ret != 0)
2387 return (ret);
2388 signotify(td);
2389 /*
2390 * Defer further processing for signals which are held,
2391 * except that stopped processes must be continued by SIGCONT.
2392 */
2393 if (action == SIG_HOLD &&
2394 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG)))
2395 return (0);
2396
2397 /*
2398 * Some signals have a process-wide effect and a per-thread
2399 * component. Most processing occurs when the process next
2400 * tries to cross the user boundary, however there are some
2401 * times when processing needs to be done immediately, such as
2402 * waking up threads so that they can cross the user boundary.
2403 * We try to do the per-process part here.
2404 */
2405 if (P_SHOULDSTOP(p)) {
2406 KASSERT(!(p->p_flag & P_WEXIT),
2407 ("signal to stopped but exiting process"));
2408 if (sig == SIGKILL) {
2409 /*
2410 * If traced process is already stopped,
2411 * then no further action is necessary.
2412 */
2413 if (p->p_flag & P_TRACED)
2414 return (0);
2415 /*
2416 * SIGKILL sets process running.
2417 * It will die elsewhere.
2418 * All threads must be restarted.
2419 */
2420 p->p_flag &= ~P_STOPPED_SIG;
2421 goto runfast;
2422 }
2423
2424 if (prop & SIGPROP_CONT) {
2425 /*
2426 * If traced process is already stopped,
2427 * then no further action is necessary.
2428 */
2429 if (p->p_flag & P_TRACED)
2430 return (0);
2431 /*
2432 * If SIGCONT is default (or ignored), we continue the
2433 * process but don't leave the signal in sigqueue as
2434 * it has no further action. If SIGCONT is held, we
2435 * continue the process and leave the signal in
2436 * sigqueue. If the process catches SIGCONT, let it
2437 * handle the signal itself. If it isn't waiting on
2438 * an event, it goes back to run state.
2439 * Otherwise, process goes back to sleep state.
2440 */
2441 p->p_flag &= ~P_STOPPED_SIG;
2442 PROC_SLOCK(p);
2443 if (p->p_numthreads == p->p_suspcount) {
2444 PROC_SUNLOCK(p);
2445 PROC_LOCK(p->p_pptr);
2446 childproc_continued(p);
2447 PROC_UNLOCK(p->p_pptr);
2448 PROC_SLOCK(p);
2449 }
2450 if (action == SIG_DFL) {
2451 thread_unsuspend(p);
2452 PROC_SUNLOCK(p);
2453 sigqueue_delete(sigqueue, sig);
2454 goto out_cont;
2455 }
2456 if (action == SIG_CATCH) {
2457 /*
2458 * The process wants to catch it so it needs
2459 * to run at least one thread, but which one?
2460 */
2461 PROC_SUNLOCK(p);
2462 goto runfast;
2463 }
2464 /*
2465 * The signal is not ignored or caught.
2466 */
2467 thread_unsuspend(p);
2468 PROC_SUNLOCK(p);
2469 goto out_cont;
2470 }
2471
2472 if (prop & SIGPROP_STOP) {
2473 /*
2474 * If traced process is already stopped,
2475 * then no further action is necessary.
2476 */
2477 if (p->p_flag & P_TRACED)
2478 return (0);
2479 /*
2480 * Already stopped, don't need to stop again
2481 * (If we did the shell could get confused).
2482 * Just make sure the signal STOP bit set.
2483 */
2484 p->p_flag |= P_STOPPED_SIG;
2485 sigqueue_delete(sigqueue, sig);
2486 return (0);
2487 }
2488
2489 /*
2490 * All other kinds of signals:
2491 * If a thread is sleeping interruptibly, simulate a
2492 * wakeup so that when it is continued it will be made
2493 * runnable and can look at the signal. However, don't make
2494 * the PROCESS runnable, leave it stopped.
2495 * It may run a bit until it hits a thread_suspend_check().
2496 */
2497 PROC_SLOCK(p);
2498 thread_lock(td);
2499 if (TD_CAN_ABORT(td))
2500 sig_sleepq_abort(td, intrval);
2501 else
2502 thread_unlock(td);
2503 PROC_SUNLOCK(p);
2504 return (0);
2505 /*
2506 * Mutexes are short lived. Threads waiting on them will
2507 * hit thread_suspend_check() soon.
2508 */
2509 } else if (p->p_state == PRS_NORMAL) {
2510 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2511 tdsigwakeup(td, sig, action, intrval);
2512 return (0);
2513 }
2514
2515 MPASS(action == SIG_DFL);
2516
2517 if (prop & SIGPROP_STOP) {
2518 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2519 return (0);
2520 p->p_flag |= P_STOPPED_SIG;
2521 p->p_xsig = sig;
2522 PROC_SLOCK(p);
2523 sig_suspend_threads(td, p);
2524 if (p->p_numthreads == p->p_suspcount) {
2525 /*
2526 * only thread sending signal to another
2527 * process can reach here, if thread is sending
2528 * signal to its process, because thread does
2529 * not suspend itself here, p_numthreads
2530 * should never be equal to p_suspcount.
2531 */
2532 thread_stopped(p);
2533 PROC_SUNLOCK(p);
2534 sigqueue_delete_proc(p, p->p_xsig);
2535 } else
2536 PROC_SUNLOCK(p);
2537 return (0);
2538 }
2539 } else {
2540 /* Not in "NORMAL" state. discard the signal. */
2541 sigqueue_delete(sigqueue, sig);
2542 return (0);
2543 }
2544
2545 /*
2546 * The process is not stopped so we need to apply the signal to all the
2547 * running threads.
2548 */
2549 runfast:
2550 tdsigwakeup(td, sig, action, intrval);
2551 PROC_SLOCK(p);
2552 thread_unsuspend(p);
2553 PROC_SUNLOCK(p);
2554 out_cont:
2555 itimer_proc_continue(p);
2556 kqtimer_proc_continue(p);
2557
2558 return (0);
2559 }
2560
2561 /*
2562 * The force of a signal has been directed against a single
2563 * thread. We need to see what we can do about knocking it
2564 * out of any sleep it may be in etc.
2565 */
2566 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2567 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2568 {
2569 struct proc *p = td->td_proc;
2570 int prop;
2571
2572 PROC_LOCK_ASSERT(p, MA_OWNED);
2573 prop = sigprop(sig);
2574
2575 PROC_SLOCK(p);
2576 thread_lock(td);
2577 /*
2578 * Bring the priority of a thread up if we want it to get
2579 * killed in this lifetime. Be careful to avoid bumping the
2580 * priority of the idle thread, since we still allow to signal
2581 * kernel processes.
2582 */
2583 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 &&
2584 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2585 sched_prio(td, PUSER);
2586 if (TD_ON_SLEEPQ(td)) {
2587 /*
2588 * If thread is sleeping uninterruptibly
2589 * we can't interrupt the sleep... the signal will
2590 * be noticed when the process returns through
2591 * trap() or syscall().
2592 */
2593 if ((td->td_flags & TDF_SINTR) == 0)
2594 goto out;
2595 /*
2596 * If SIGCONT is default (or ignored) and process is
2597 * asleep, we are finished; the process should not
2598 * be awakened.
2599 */
2600 if ((prop & SIGPROP_CONT) && action == SIG_DFL) {
2601 thread_unlock(td);
2602 PROC_SUNLOCK(p);
2603 sigqueue_delete(&p->p_sigqueue, sig);
2604 /*
2605 * It may be on either list in this state.
2606 * Remove from both for now.
2607 */
2608 sigqueue_delete(&td->td_sigqueue, sig);
2609 return;
2610 }
2611
2612 /*
2613 * Don't awaken a sleeping thread for SIGSTOP if the
2614 * STOP signal is deferred.
2615 */
2616 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2617 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2618 goto out;
2619
2620 /*
2621 * Give low priority threads a better chance to run.
2622 */
2623 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2624 sched_prio(td, PUSER);
2625
2626 sig_sleepq_abort(td, intrval);
2627 PROC_SUNLOCK(p);
2628 return;
2629 }
2630
2631 /*
2632 * Other states do nothing with the signal immediately,
2633 * other than kicking ourselves if we are running.
2634 * It will either never be noticed, or noticed very soon.
2635 */
2636 #ifdef SMP
2637 if (TD_IS_RUNNING(td) && td != curthread)
2638 forward_signal(td);
2639 #endif
2640
2641 out:
2642 PROC_SUNLOCK(p);
2643 thread_unlock(td);
2644 }
2645
2646 static void
ptrace_coredumpreq(struct thread * td,struct proc * p,struct thr_coredump_req * tcq)2647 ptrace_coredumpreq(struct thread *td, struct proc *p,
2648 struct thr_coredump_req *tcq)
2649 {
2650 struct coredump_vnode_ctx wctx;
2651 struct coredump_writer cdw;
2652 void *rl_cookie;
2653
2654 if (p->p_sysent->sv_coredump == NULL) {
2655 tcq->tc_error = ENOSYS;
2656 return;
2657 }
2658
2659 memset(&wctx, 0, sizeof(wctx));
2660 wctx.vp = tcq->tc_vp;
2661 wctx.fcred = NOCRED;
2662
2663 memset(&cdw, 0, sizeof(wctx));
2664 cdw.ctx = &wctx;
2665 cdw.write_fn = core_vn_write;
2666 cdw.extend_fn = core_vn_extend;
2667
2668 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX);
2669 tcq->tc_error = p->p_sysent->sv_coredump(td, &cdw,
2670 tcq->tc_limit, tcq->tc_flags);
2671 vn_rangelock_unlock(tcq->tc_vp, rl_cookie);
2672 }
2673
2674 static void
ptrace_syscallreq(struct thread * td,struct proc * p,struct thr_syscall_req * tsr)2675 ptrace_syscallreq(struct thread *td, struct proc *p,
2676 struct thr_syscall_req *tsr)
2677 {
2678 struct sysentvec *sv;
2679 struct sysent *se;
2680 register_t rv_saved[2];
2681 int error, nerror;
2682 int sc;
2683 bool audited, sy_thr_static;
2684
2685 sv = p->p_sysent;
2686 if (sv->sv_table == NULL || sv->sv_size < tsr->ts_sa.code) {
2687 tsr->ts_ret.sr_error = ENOSYS;
2688 return;
2689 }
2690
2691 sc = tsr->ts_sa.code;
2692 if (sc == SYS_syscall || sc == SYS___syscall) {
2693 sc = tsr->ts_sa.args[0];
2694 memmove(&tsr->ts_sa.args[0], &tsr->ts_sa.args[1],
2695 sizeof(register_t) * (tsr->ts_nargs - 1));
2696 }
2697
2698 tsr->ts_sa.callp = se = &sv->sv_table[sc];
2699
2700 VM_CNT_INC(v_syscall);
2701 td->td_pticks = 0;
2702 if (__predict_false(td->td_cowgen != atomic_load_int(
2703 &td->td_proc->p_cowgen)))
2704 thread_cow_update(td);
2705
2706 td->td_sa = tsr->ts_sa;
2707
2708 #ifdef CAPABILITY_MODE
2709 if ((se->sy_flags & SYF_CAPENABLED) == 0) {
2710 if (CAP_TRACING(td))
2711 ktrcapfail(CAPFAIL_SYSCALL, NULL);
2712 if (IN_CAPABILITY_MODE(td)) {
2713 tsr->ts_ret.sr_error = ECAPMODE;
2714 return;
2715 }
2716 }
2717 #endif
2718
2719 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2720 audited = AUDIT_SYSCALL_ENTER(sc, td) != 0;
2721
2722 if (!sy_thr_static) {
2723 error = syscall_thread_enter(td, &se);
2724 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2725 if (error != 0) {
2726 tsr->ts_ret.sr_error = error;
2727 return;
2728 }
2729 }
2730
2731 rv_saved[0] = td->td_retval[0];
2732 rv_saved[1] = td->td_retval[1];
2733 nerror = td->td_errno;
2734 td->td_retval[0] = 0;
2735 td->td_retval[1] = 0;
2736
2737 #ifdef KDTRACE_HOOKS
2738 if (se->sy_entry != 0)
2739 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_ENTRY, 0);
2740 #endif
2741 tsr->ts_ret.sr_error = se->sy_call(td, tsr->ts_sa.args);
2742 #ifdef KDTRACE_HOOKS
2743 if (se->sy_return != 0)
2744 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_RETURN,
2745 tsr->ts_ret.sr_error != 0 ? -1 : td->td_retval[0]);
2746 #endif
2747
2748 tsr->ts_ret.sr_retval[0] = td->td_retval[0];
2749 tsr->ts_ret.sr_retval[1] = td->td_retval[1];
2750 td->td_retval[0] = rv_saved[0];
2751 td->td_retval[1] = rv_saved[1];
2752 td->td_errno = nerror;
2753
2754 if (audited)
2755 AUDIT_SYSCALL_EXIT(error, td);
2756 if (!sy_thr_static)
2757 syscall_thread_exit(td, se);
2758 }
2759
2760 static void
ptrace_remotereq(struct thread * td,int flag)2761 ptrace_remotereq(struct thread *td, int flag)
2762 {
2763 struct proc *p;
2764
2765 MPASS(td == curthread);
2766 p = td->td_proc;
2767 PROC_LOCK_ASSERT(p, MA_OWNED);
2768 if ((td->td_dbgflags & flag) == 0)
2769 return;
2770 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped"));
2771 KASSERT(td->td_remotereq != NULL, ("td_remotereq is NULL"));
2772
2773 PROC_UNLOCK(p);
2774 switch (flag) {
2775 case TDB_COREDUMPREQ:
2776 ptrace_coredumpreq(td, p, td->td_remotereq);
2777 break;
2778 case TDB_SCREMOTEREQ:
2779 ptrace_syscallreq(td, p, td->td_remotereq);
2780 break;
2781 default:
2782 __unreachable();
2783 }
2784 PROC_LOCK(p);
2785
2786 MPASS((td->td_dbgflags & flag) != 0);
2787 td->td_dbgflags &= ~flag;
2788 td->td_remotereq = NULL;
2789 wakeup(p);
2790 }
2791
2792 /*
2793 * Suspend threads of the process p, either by directly setting the
2794 * inhibitor for the thread sleeping interruptibly, or by making the
2795 * thread suspend at the userspace boundary by scheduling a suspend AST.
2796 *
2797 * Returns true if some threads were suspended directly from the
2798 * sleeping state, and false if all threads are forced to process AST.
2799 */
2800 static bool
sig_suspend_threads(struct thread * td,struct proc * p)2801 sig_suspend_threads(struct thread *td, struct proc *p)
2802 {
2803 struct thread *td2;
2804 bool res;
2805
2806 PROC_LOCK_ASSERT(p, MA_OWNED);
2807 PROC_SLOCK_ASSERT(p, MA_OWNED);
2808
2809 res = false;
2810 FOREACH_THREAD_IN_PROC(p, td2) {
2811 thread_lock(td2);
2812 ast_sched_locked(td2, TDA_SUSPEND);
2813 if (TD_IS_SLEEPING(td2) && (td2->td_flags & TDF_SINTR) != 0) {
2814 if (td2->td_flags & TDF_SBDRY) {
2815 /*
2816 * Once a thread is asleep with
2817 * TDF_SBDRY and without TDF_SERESTART
2818 * or TDF_SEINTR set, it should never
2819 * become suspended due to this check.
2820 */
2821 KASSERT(!TD_IS_SUSPENDED(td2),
2822 ("thread with deferred stops suspended"));
2823 if (TD_SBDRY_INTR(td2)) {
2824 sleepq_abort(td2, TD_SBDRY_ERRNO(td2));
2825 continue;
2826 }
2827 } else if (!TD_IS_SUSPENDED(td2)) {
2828 thread_suspend_one(td2);
2829 res = true;
2830 }
2831 } else if (!TD_IS_SUSPENDED(td2)) {
2832 #ifdef SMP
2833 if (TD_IS_RUNNING(td2) && td2 != td)
2834 forward_signal(td2);
2835 #endif
2836 }
2837 thread_unlock(td2);
2838 }
2839 return (res);
2840 }
2841
2842 static void
sig_handle_first_stop(struct thread * td,struct proc * p,int sig)2843 sig_handle_first_stop(struct thread *td, struct proc *p, int sig)
2844 {
2845 if (td != NULL && (td->td_dbgflags & TDB_FSTP) == 0 &&
2846 ((p->p_flag2 & P2_PTRACE_FSTP) != 0 || p->p_xthread != NULL))
2847 return;
2848
2849 p->p_xsig = sig;
2850 p->p_xthread = td;
2851
2852 /*
2853 * If we are on sleepqueue already, let sleepqueue
2854 * code decide if it needs to go sleep after attach.
2855 */
2856 if (td != NULL && td->td_wchan == NULL)
2857 td->td_dbgflags &= ~TDB_FSTP;
2858
2859 p->p_flag2 &= ~P2_PTRACE_FSTP;
2860 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2861 if (sig_suspend_threads(td, p) && td == NULL)
2862 thread_stopped(p);
2863 }
2864
2865 /*
2866 * Stop the process for an event deemed interesting to the debugger. If si is
2867 * non-NULL, this is a signal exchange; the new signal requested by the
2868 * debugger will be returned for handling. If si is NULL, this is some other
2869 * type of interesting event. The debugger may request a signal be delivered in
2870 * that case as well, however it will be deferred until it can be handled.
2871 */
2872 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2873 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2874 {
2875 struct proc *p = td->td_proc;
2876 struct thread *td2;
2877 ksiginfo_t ksi;
2878
2879 PROC_LOCK_ASSERT(p, MA_OWNED);
2880 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2881 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2882 &p->p_mtx.lock_object, "Stopping for traced signal");
2883
2884 td->td_xsig = sig;
2885
2886 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2887 td->td_dbgflags |= TDB_XSIG;
2888 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2889 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2890 PROC_SLOCK(p);
2891 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2892 if (P_KILLED(p)) {
2893 /*
2894 * Ensure that, if we've been PT_KILLed, the
2895 * exit status reflects that. Another thread
2896 * may also be in ptracestop(), having just
2897 * received the SIGKILL, but this thread was
2898 * unsuspended first.
2899 */
2900 td->td_dbgflags &= ~TDB_XSIG;
2901 td->td_xsig = SIGKILL;
2902 p->p_ptevents = 0;
2903 break;
2904 }
2905 if (p->p_flag & P_SINGLE_EXIT &&
2906 !(td->td_dbgflags & TDB_EXIT)) {
2907 /*
2908 * Ignore ptrace stops except for thread exit
2909 * events when the process exits.
2910 */
2911 td->td_dbgflags &= ~TDB_XSIG;
2912 PROC_SUNLOCK(p);
2913 return (0);
2914 }
2915
2916 /*
2917 * Make wait(2) work. Ensure that right after the
2918 * attach, the thread which was decided to become the
2919 * leader of attach gets reported to the waiter.
2920 * Otherwise, just avoid overwriting another thread's
2921 * assignment to p_xthread. If another thread has
2922 * already set p_xthread, the current thread will get
2923 * a chance to report itself upon the next iteration.
2924 */
2925 sig_handle_first_stop(td, p, sig);
2926
2927 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2928 td->td_dbgflags &= ~TDB_STOPATFORK;
2929 }
2930 stopme:
2931 td->td_dbgflags |= TDB_SSWITCH;
2932 thread_suspend_switch(td, p);
2933 td->td_dbgflags &= ~TDB_SSWITCH;
2934 if ((td->td_dbgflags & (TDB_COREDUMPREQ |
2935 TDB_SCREMOTEREQ)) != 0) {
2936 MPASS((td->td_dbgflags & (TDB_COREDUMPREQ |
2937 TDB_SCREMOTEREQ)) !=
2938 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2939 PROC_SUNLOCK(p);
2940 ptrace_remotereq(td, td->td_dbgflags &
2941 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2942 PROC_SLOCK(p);
2943 goto stopme;
2944 }
2945 if (p->p_xthread == td)
2946 p->p_xthread = NULL;
2947 if (!(p->p_flag & P_TRACED))
2948 break;
2949 if (td->td_dbgflags & TDB_SUSPEND) {
2950 if (p->p_flag & P_SINGLE_EXIT)
2951 break;
2952 goto stopme;
2953 }
2954 }
2955 PROC_SUNLOCK(p);
2956 }
2957
2958 if (si != NULL && sig == td->td_xsig) {
2959 /* Parent wants us to take the original signal unchanged. */
2960 si->ksi_flags |= KSI_HEAD;
2961 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2962 si->ksi_signo = 0;
2963 } else if (td->td_xsig != 0) {
2964 /*
2965 * If parent wants us to take a new signal, then it will leave
2966 * it in td->td_xsig; otherwise we just look for signals again.
2967 */
2968 ksiginfo_init(&ksi);
2969 ksi.ksi_signo = td->td_xsig;
2970 ksi.ksi_flags |= KSI_PTRACE;
2971 td2 = sigtd(p, td->td_xsig, false);
2972 tdsendsignal(p, td2, td->td_xsig, &ksi);
2973 if (td != td2)
2974 return (0);
2975 }
2976
2977 return (td->td_xsig);
2978 }
2979
2980 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2981 reschedule_signals(struct proc *p, sigset_t block, int flags)
2982 {
2983 struct sigacts *ps;
2984 struct thread *td;
2985 int sig;
2986 bool fastblk, pslocked;
2987
2988 PROC_LOCK_ASSERT(p, MA_OWNED);
2989 ps = p->p_sigacts;
2990 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0;
2991 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED);
2992 if (SIGISEMPTY(p->p_siglist))
2993 return;
2994 SIGSETAND(block, p->p_siglist);
2995 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0;
2996 SIG_FOREACH(sig, &block) {
2997 td = sigtd(p, sig, fastblk);
2998
2999 /*
3000 * If sigtd() selected us despite sigfastblock is
3001 * blocking, do not activate AST or wake us, to avoid
3002 * loop in AST handler.
3003 */
3004 if (fastblk && td == curthread)
3005 continue;
3006
3007 signotify(td);
3008 if (!pslocked)
3009 mtx_lock(&ps->ps_mtx);
3010 if (p->p_flag & P_TRACED ||
3011 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
3012 !SIGISMEMBER(td->td_sigmask, sig))) {
3013 tdsigwakeup(td, sig, SIG_CATCH,
3014 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
3015 ERESTART));
3016 }
3017 if (!pslocked)
3018 mtx_unlock(&ps->ps_mtx);
3019 }
3020 }
3021
3022 void
tdsigcleanup(struct thread * td)3023 tdsigcleanup(struct thread *td)
3024 {
3025 struct proc *p;
3026 sigset_t unblocked;
3027
3028 p = td->td_proc;
3029 PROC_LOCK_ASSERT(p, MA_OWNED);
3030
3031 sigqueue_flush(&td->td_sigqueue);
3032 if (p->p_numthreads == 1)
3033 return;
3034
3035 /*
3036 * Since we cannot handle signals, notify signal post code
3037 * about this by filling the sigmask.
3038 *
3039 * Also, if needed, wake up thread(s) that do not block the
3040 * same signals as the exiting thread, since the thread might
3041 * have been selected for delivery and woken up.
3042 */
3043 SIGFILLSET(unblocked);
3044 SIGSETNAND(unblocked, td->td_sigmask);
3045 SIGFILLSET(td->td_sigmask);
3046 reschedule_signals(p, unblocked, 0);
3047
3048 }
3049
3050 static int
sigdeferstop_curr_flags(int cflags)3051 sigdeferstop_curr_flags(int cflags)
3052 {
3053
3054 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
3055 (cflags & TDF_SBDRY) != 0);
3056 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
3057 }
3058
3059 /*
3060 * Defer the delivery of SIGSTOP for the current thread, according to
3061 * the requested mode. Returns previous flags, which must be restored
3062 * by sigallowstop().
3063 *
3064 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
3065 * cleared by the current thread, which allow the lock-less read-only
3066 * accesses below.
3067 */
3068 int
sigdeferstop_impl(int mode)3069 sigdeferstop_impl(int mode)
3070 {
3071 struct thread *td;
3072 int cflags, nflags;
3073
3074 td = curthread;
3075 cflags = sigdeferstop_curr_flags(td->td_flags);
3076 switch (mode) {
3077 case SIGDEFERSTOP_NOP:
3078 nflags = cflags;
3079 break;
3080 case SIGDEFERSTOP_OFF:
3081 nflags = 0;
3082 break;
3083 case SIGDEFERSTOP_SILENT:
3084 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
3085 break;
3086 case SIGDEFERSTOP_EINTR:
3087 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
3088 break;
3089 case SIGDEFERSTOP_ERESTART:
3090 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
3091 break;
3092 default:
3093 panic("sigdeferstop: invalid mode %x", mode);
3094 break;
3095 }
3096 if (cflags == nflags)
3097 return (SIGDEFERSTOP_VAL_NCHG);
3098 thread_lock(td);
3099 td->td_flags = (td->td_flags & ~cflags) | nflags;
3100 thread_unlock(td);
3101 return (cflags);
3102 }
3103
3104 /*
3105 * Restores the STOP handling mode, typically permitting the delivery
3106 * of SIGSTOP for the current thread. This does not immediately
3107 * suspend if a stop was posted. Instead, the thread will suspend
3108 * either via ast() or a subsequent interruptible sleep.
3109 */
3110 void
sigallowstop_impl(int prev)3111 sigallowstop_impl(int prev)
3112 {
3113 struct thread *td;
3114 int cflags;
3115
3116 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
3117 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
3118 ("sigallowstop: incorrect previous mode %x", prev));
3119 td = curthread;
3120 cflags = sigdeferstop_curr_flags(td->td_flags);
3121 if (cflags != prev) {
3122 thread_lock(td);
3123 td->td_flags = (td->td_flags & ~cflags) | prev;
3124 thread_unlock(td);
3125 }
3126 }
3127
3128 enum sigstatus {
3129 SIGSTATUS_HANDLE,
3130 SIGSTATUS_HANDLED,
3131 SIGSTATUS_IGNORE,
3132 SIGSTATUS_SBDRY_STOP,
3133 };
3134
3135 /*
3136 * The thread has signal "sig" pending. Figure out what to do with it:
3137 *
3138 * _HANDLE -> the caller should handle the signal
3139 * _HANDLED -> handled internally, reload pending signal set
3140 * _IGNORE -> ignored, remove from the set of pending signals and try the
3141 * next pending signal
3142 * _SBDRY_STOP -> the signal should stop the thread but this is not
3143 * permitted in the current context
3144 */
3145 static enum sigstatus
sigprocess(struct thread * td,int sig)3146 sigprocess(struct thread *td, int sig)
3147 {
3148 struct proc *p;
3149 struct sigacts *ps;
3150 struct sigqueue *queue;
3151 ksiginfo_t ksi;
3152 int prop;
3153
3154 KASSERT(_SIG_VALID(sig), ("%s: invalid signal %d", __func__, sig));
3155
3156 p = td->td_proc;
3157 ps = p->p_sigacts;
3158 mtx_assert(&ps->ps_mtx, MA_OWNED);
3159 PROC_LOCK_ASSERT(p, MA_OWNED);
3160
3161 /*
3162 * We should allow pending but ignored signals below
3163 * if there is sigwait() active, or P_TRACED was
3164 * on when they were posted.
3165 */
3166 if (SIGISMEMBER(ps->ps_sigignore, sig) &&
3167 (p->p_flag & P_TRACED) == 0 &&
3168 (td->td_flags & TDF_SIGWAIT) == 0) {
3169 return (SIGSTATUS_IGNORE);
3170 }
3171
3172 /*
3173 * If the process is going to single-thread mode to prepare
3174 * for exit, there is no sense in delivering any signal
3175 * to usermode. Another important consequence is that
3176 * msleep(..., PCATCH, ...) now is only interruptible by a
3177 * suspend request.
3178 */
3179 if ((p->p_flag2 & P2_WEXIT) != 0)
3180 return (SIGSTATUS_IGNORE);
3181
3182 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
3183 /*
3184 * If traced, always stop.
3185 * Remove old signal from queue before the stop.
3186 * XXX shrug off debugger, it causes siginfo to
3187 * be thrown away.
3188 */
3189 queue = &td->td_sigqueue;
3190 ksiginfo_init(&ksi);
3191 if (sigqueue_get(queue, sig, &ksi) == 0) {
3192 queue = &p->p_sigqueue;
3193 sigqueue_get(queue, sig, &ksi);
3194 }
3195 td->td_si = ksi.ksi_info;
3196
3197 mtx_unlock(&ps->ps_mtx);
3198 sig = ptracestop(td, sig, &ksi);
3199 mtx_lock(&ps->ps_mtx);
3200
3201 td->td_si.si_signo = 0;
3202
3203 /*
3204 * Keep looking if the debugger discarded or
3205 * replaced the signal.
3206 */
3207 if (sig == 0)
3208 return (SIGSTATUS_HANDLED);
3209
3210 /*
3211 * If the signal became masked, re-queue it.
3212 */
3213 if (SIGISMEMBER(td->td_sigmask, sig)) {
3214 ksi.ksi_flags |= KSI_HEAD;
3215 sigqueue_add(&p->p_sigqueue, sig, &ksi);
3216 return (SIGSTATUS_HANDLED);
3217 }
3218
3219 /*
3220 * If the traced bit got turned off, requeue the signal and
3221 * reload the set of pending signals. This ensures that p_sig*
3222 * and p_sigact are consistent.
3223 */
3224 if ((p->p_flag & P_TRACED) == 0) {
3225 if ((ksi.ksi_flags & KSI_PTRACE) == 0) {
3226 ksi.ksi_flags |= KSI_HEAD;
3227 sigqueue_add(queue, sig, &ksi);
3228 }
3229 return (SIGSTATUS_HANDLED);
3230 }
3231 }
3232
3233 /*
3234 * Decide whether the signal should be returned.
3235 * Return the signal's number, or fall through
3236 * to clear it from the pending mask.
3237 */
3238 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
3239 case (intptr_t)SIG_DFL:
3240 /*
3241 * Don't take default actions on system processes.
3242 */
3243 if (p->p_pid <= 1) {
3244 #ifdef DIAGNOSTIC
3245 /*
3246 * Are you sure you want to ignore SIGSEGV
3247 * in init? XXX
3248 */
3249 printf("Process (pid %lu) got signal %d\n",
3250 (u_long)p->p_pid, sig);
3251 #endif
3252 return (SIGSTATUS_IGNORE);
3253 }
3254
3255 /*
3256 * If there is a pending stop signal to process with
3257 * default action, stop here, then clear the signal.
3258 * Traced or exiting processes should ignore stops.
3259 * Additionally, a member of an orphaned process group
3260 * should ignore tty stops.
3261 */
3262 prop = sigprop(sig);
3263 if (prop & SIGPROP_STOP) {
3264 mtx_unlock(&ps->ps_mtx);
3265 if ((p->p_flag & (P_TRACED | P_WEXIT |
3266 P_SINGLE_EXIT)) != 0 || ((p->p_pgrp->
3267 pg_flags & PGRP_ORPHANED) != 0 &&
3268 (prop & SIGPROP_TTYSTOP) != 0)) {
3269 mtx_lock(&ps->ps_mtx);
3270 return (SIGSTATUS_IGNORE);
3271 }
3272 if (TD_SBDRY_INTR(td)) {
3273 KASSERT((td->td_flags & TDF_SBDRY) != 0,
3274 ("lost TDF_SBDRY"));
3275 mtx_lock(&ps->ps_mtx);
3276 return (SIGSTATUS_SBDRY_STOP);
3277 }
3278 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
3279 &p->p_mtx.lock_object, "Catching SIGSTOP");
3280 sigqueue_delete(&td->td_sigqueue, sig);
3281 sigqueue_delete(&p->p_sigqueue, sig);
3282 p->p_flag |= P_STOPPED_SIG;
3283 p->p_xsig = sig;
3284 PROC_SLOCK(p);
3285 sig_suspend_threads(td, p);
3286 thread_suspend_switch(td, p);
3287 PROC_SUNLOCK(p);
3288 mtx_lock(&ps->ps_mtx);
3289 return (SIGSTATUS_HANDLED);
3290 } else if ((prop & SIGPROP_IGNORE) != 0 &&
3291 (td->td_flags & TDF_SIGWAIT) == 0) {
3292 /*
3293 * Default action is to ignore; drop it if
3294 * not in kern_sigtimedwait().
3295 */
3296 return (SIGSTATUS_IGNORE);
3297 } else {
3298 return (SIGSTATUS_HANDLE);
3299 }
3300
3301 case (intptr_t)SIG_IGN:
3302 if ((td->td_flags & TDF_SIGWAIT) == 0)
3303 return (SIGSTATUS_IGNORE);
3304 else
3305 return (SIGSTATUS_HANDLE);
3306
3307 default:
3308 /*
3309 * This signal has an action, let postsig() process it.
3310 */
3311 return (SIGSTATUS_HANDLE);
3312 }
3313 }
3314
3315 /*
3316 * If the current process has received a signal (should be caught or cause
3317 * termination, should interrupt current syscall), return the signal number.
3318 * Stop signals with default action are processed immediately, then cleared;
3319 * they aren't returned. This is checked after each entry to the system for
3320 * a syscall or trap (though this can usually be done without calling
3321 * issignal by checking the pending signal masks in cursig.) The normal call
3322 * sequence is
3323 *
3324 * while (sig = cursig(curthread))
3325 * postsig(sig);
3326 */
3327 static int
issignal(struct thread * td)3328 issignal(struct thread *td)
3329 {
3330 struct proc *p;
3331 sigset_t sigpending;
3332 int sig;
3333
3334 p = td->td_proc;
3335 PROC_LOCK_ASSERT(p, MA_OWNED);
3336
3337 for (;;) {
3338 sigpending = td->td_sigqueue.sq_signals;
3339 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
3340 SIGSETNAND(sigpending, td->td_sigmask);
3341
3342 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
3343 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
3344 SIG_STOPSIGMASK(sigpending);
3345 if (SIGISEMPTY(sigpending)) /* no signal to send */
3346 return (0);
3347
3348 /*
3349 * Do fast sigblock if requested by usermode. Since
3350 * we do know that there was a signal pending at this
3351 * point, set the FAST_SIGBLOCK_PEND as indicator for
3352 * usermode to perform a dummy call to
3353 * FAST_SIGBLOCK_UNBLOCK, which causes immediate
3354 * delivery of postponed pending signal.
3355 */
3356 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
3357 if (td->td_sigblock_val != 0)
3358 SIGSETNAND(sigpending, fastblock_mask);
3359 if (SIGISEMPTY(sigpending)) {
3360 td->td_pflags |= TDP_SIGFASTPENDING;
3361 return (0);
3362 }
3363 }
3364
3365 if (!pt_attach_transparent &&
3366 (p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
3367 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
3368 SIGISMEMBER(sigpending, SIGSTOP)) {
3369 /*
3370 * If debugger just attached, always consume
3371 * SIGSTOP from ptrace(PT_ATTACH) first, to
3372 * execute the debugger attach ritual in
3373 * order.
3374 */
3375 td->td_dbgflags |= TDB_FSTP;
3376 SIGEMPTYSET(sigpending);
3377 SIGADDSET(sigpending, SIGSTOP);
3378 }
3379
3380 SIG_FOREACH(sig, &sigpending) {
3381 switch (sigprocess(td, sig)) {
3382 case SIGSTATUS_HANDLE:
3383 return (sig);
3384 case SIGSTATUS_HANDLED:
3385 goto next;
3386 case SIGSTATUS_IGNORE:
3387 sigqueue_delete(&td->td_sigqueue, sig);
3388 sigqueue_delete(&p->p_sigqueue, sig);
3389 break;
3390 case SIGSTATUS_SBDRY_STOP:
3391 return (-1);
3392 }
3393 }
3394 next:;
3395 }
3396 }
3397
3398 void
thread_stopped(struct proc * p)3399 thread_stopped(struct proc *p)
3400 {
3401 int n;
3402
3403 PROC_LOCK_ASSERT(p, MA_OWNED);
3404 PROC_SLOCK_ASSERT(p, MA_OWNED);
3405 n = p->p_suspcount;
3406 if (p == curproc)
3407 n++;
3408 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
3409 PROC_SUNLOCK(p);
3410 p->p_flag &= ~P_WAITED;
3411 PROC_LOCK(p->p_pptr);
3412 childproc_stopped(p, (p->p_flag & P_TRACED) ?
3413 CLD_TRAPPED : CLD_STOPPED);
3414 PROC_UNLOCK(p->p_pptr);
3415 PROC_SLOCK(p);
3416 }
3417 }
3418
3419 /*
3420 * Take the action for the specified signal
3421 * from the current set of pending signals.
3422 */
3423 int
postsig(int sig)3424 postsig(int sig)
3425 {
3426 struct thread *td;
3427 struct proc *p;
3428 struct sigacts *ps;
3429 sig_t action;
3430 ksiginfo_t ksi;
3431 sigset_t returnmask;
3432
3433 KASSERT(sig != 0, ("postsig"));
3434
3435 td = curthread;
3436 p = td->td_proc;
3437 PROC_LOCK_ASSERT(p, MA_OWNED);
3438 ps = p->p_sigacts;
3439 mtx_assert(&ps->ps_mtx, MA_OWNED);
3440 ksiginfo_init(&ksi);
3441 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3442 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3443 return (0);
3444 ksi.ksi_signo = sig;
3445 if (ksi.ksi_code == SI_TIMER)
3446 itimer_accept(p, ksi.ksi_timerid, &ksi);
3447 action = ps->ps_sigact[_SIG_IDX(sig)];
3448 #ifdef KTRACE
3449 if (KTRPOINT(td, KTR_PSIG))
3450 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3451 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3452 #endif
3453
3454 if (action == SIG_DFL) {
3455 /*
3456 * Default action, where the default is to kill
3457 * the process. (Other cases were ignored above.)
3458 */
3459 mtx_unlock(&ps->ps_mtx);
3460 proc_td_siginfo_capture(td, &ksi.ksi_info);
3461 sigexit(td, sig);
3462 /* NOTREACHED */
3463 } else {
3464 /*
3465 * If we get here, the signal must be caught.
3466 */
3467 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3468 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3469 ("postsig action: blocked sig %d", sig));
3470
3471 /*
3472 * Set the new mask value and also defer further
3473 * occurrences of this signal.
3474 *
3475 * Special case: user has done a sigsuspend. Here the
3476 * current mask is not of interest, but rather the
3477 * mask from before the sigsuspend is what we want
3478 * restored after the signal processing is completed.
3479 */
3480 if (td->td_pflags & TDP_OLDMASK) {
3481 returnmask = td->td_oldsigmask;
3482 td->td_pflags &= ~TDP_OLDMASK;
3483 } else
3484 returnmask = td->td_sigmask;
3485
3486 if (p->p_sig == sig) {
3487 p->p_sig = 0;
3488 }
3489 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3490 postsig_done(sig, td, ps);
3491 }
3492 return (1);
3493 }
3494
3495 int
sig_ast_checksusp(struct thread * td)3496 sig_ast_checksusp(struct thread *td)
3497 {
3498 struct proc *p __diagused;
3499 int ret;
3500
3501 p = td->td_proc;
3502 PROC_LOCK_ASSERT(p, MA_OWNED);
3503
3504 if (!td_ast_pending(td, TDA_SUSPEND))
3505 return (0);
3506
3507 ret = thread_suspend_check(1);
3508 MPASS(ret == 0 || ret == EINTR || ret == ERESTART);
3509 return (ret);
3510 }
3511
3512 int
sig_ast_needsigchk(struct thread * td)3513 sig_ast_needsigchk(struct thread *td)
3514 {
3515 struct proc *p;
3516 struct sigacts *ps;
3517 int ret, sig;
3518
3519 p = td->td_proc;
3520 PROC_LOCK_ASSERT(p, MA_OWNED);
3521
3522 if (!td_ast_pending(td, TDA_SIG))
3523 return (0);
3524
3525 ps = p->p_sigacts;
3526 mtx_lock(&ps->ps_mtx);
3527 sig = cursig(td);
3528 if (sig == -1) {
3529 mtx_unlock(&ps->ps_mtx);
3530 KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY"));
3531 KASSERT(TD_SBDRY_INTR(td),
3532 ("lost TDF_SERESTART of TDF_SEINTR"));
3533 KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) !=
3534 (TDF_SEINTR | TDF_SERESTART),
3535 ("both TDF_SEINTR and TDF_SERESTART"));
3536 ret = TD_SBDRY_ERRNO(td);
3537 } else if (sig != 0) {
3538 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART;
3539 mtx_unlock(&ps->ps_mtx);
3540 } else {
3541 mtx_unlock(&ps->ps_mtx);
3542 ret = 0;
3543 }
3544
3545 /*
3546 * Do not go into sleep if this thread was the ptrace(2)
3547 * attach leader. cursig() consumed SIGSTOP from PT_ATTACH,
3548 * but we usually act on the signal by interrupting sleep, and
3549 * should do that here as well.
3550 */
3551 if ((td->td_dbgflags & TDB_FSTP) != 0) {
3552 if (ret == 0)
3553 ret = EINTR;
3554 td->td_dbgflags &= ~TDB_FSTP;
3555 }
3556
3557 return (ret);
3558 }
3559
3560 int
sig_intr(void)3561 sig_intr(void)
3562 {
3563 struct thread *td;
3564 struct proc *p;
3565 int ret;
3566
3567 td = curthread;
3568 if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND))
3569 return (0);
3570
3571 p = td->td_proc;
3572
3573 PROC_LOCK(p);
3574 ret = sig_ast_checksusp(td);
3575 if (ret == 0)
3576 ret = sig_ast_needsigchk(td);
3577 PROC_UNLOCK(p);
3578 return (ret);
3579 }
3580
3581 bool
curproc_sigkilled(void)3582 curproc_sigkilled(void)
3583 {
3584 struct thread *td;
3585 struct proc *p;
3586 struct sigacts *ps;
3587 bool res;
3588
3589 td = curthread;
3590 if (!td_ast_pending(td, TDA_SIG))
3591 return (false);
3592
3593 p = td->td_proc;
3594 PROC_LOCK(p);
3595 ps = p->p_sigacts;
3596 mtx_lock(&ps->ps_mtx);
3597 res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) ||
3598 SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL);
3599 mtx_unlock(&ps->ps_mtx);
3600 PROC_UNLOCK(p);
3601 return (res);
3602 }
3603
3604 void
proc_wkilled(struct proc * p)3605 proc_wkilled(struct proc *p)
3606 {
3607
3608 PROC_LOCK_ASSERT(p, MA_OWNED);
3609 if ((p->p_flag & P_WKILLED) == 0)
3610 p->p_flag |= P_WKILLED;
3611 }
3612
3613 /*
3614 * Kill the current process for stated reason.
3615 */
3616 void
killproc(struct proc * p,const char * why)3617 killproc(struct proc *p, const char *why)
3618 {
3619
3620 PROC_LOCK_ASSERT(p, MA_OWNED);
3621 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3622 p->p_comm);
3623 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
3624 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
3625 p->p_ucred->cr_uid, why);
3626 proc_wkilled(p);
3627 kern_psignal(p, SIGKILL);
3628 }
3629
3630 /*
3631 * Send queued SIGCHLD to parent when child process's state
3632 * is changed.
3633 */
3634 static void
sigparent(struct proc * p,int reason,int status)3635 sigparent(struct proc *p, int reason, int status)
3636 {
3637 PROC_LOCK_ASSERT(p, MA_OWNED);
3638 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3639
3640 if (p->p_ksi != NULL) {
3641 p->p_ksi->ksi_signo = SIGCHLD;
3642 p->p_ksi->ksi_code = reason;
3643 p->p_ksi->ksi_status = status;
3644 p->p_ksi->ksi_pid = p->p_pid;
3645 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3646 if (KSI_ONQ(p->p_ksi))
3647 return;
3648 }
3649
3650 /*
3651 * Do not consume p_ksi if parent is zombie, since signal is
3652 * dropped immediately. Instead, keep it since it might be
3653 * useful for reaper.
3654 */
3655 if (p->p_pptr->p_state != PRS_ZOMBIE)
3656 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3657 }
3658
3659 static void
childproc_jobstate(struct proc * p,int reason,int sig)3660 childproc_jobstate(struct proc *p, int reason, int sig)
3661 {
3662 struct sigacts *ps;
3663
3664 PROC_LOCK_ASSERT(p, MA_OWNED);
3665 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3666
3667 /*
3668 * Wake up parent sleeping in kern_wait(), also send
3669 * SIGCHLD to parent, but SIGCHLD does not guarantee
3670 * that parent will awake, because parent may masked
3671 * the signal.
3672 */
3673 p->p_pptr->p_flag |= P_STATCHILD;
3674 wakeup(p->p_pptr);
3675
3676 ps = p->p_pptr->p_sigacts;
3677 mtx_lock(&ps->ps_mtx);
3678 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3679 mtx_unlock(&ps->ps_mtx);
3680 sigparent(p, reason, sig);
3681 } else
3682 mtx_unlock(&ps->ps_mtx);
3683 }
3684
3685 void
childproc_stopped(struct proc * p,int reason)3686 childproc_stopped(struct proc *p, int reason)
3687 {
3688
3689 childproc_jobstate(p, reason, p->p_xsig);
3690 }
3691
3692 void
childproc_continued(struct proc * p)3693 childproc_continued(struct proc *p)
3694 {
3695 PROC_LOCK_ASSERT(p, MA_OWNED);
3696 p->p_flag |= P_CONTINUED;
3697 p->p_xsig = SIGCONT;
3698 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3699 }
3700
3701 void
childproc_exited(struct proc * p)3702 childproc_exited(struct proc *p)
3703 {
3704 int reason, status;
3705
3706 if (WCOREDUMP(p->p_xsig)) {
3707 reason = CLD_DUMPED;
3708 status = WTERMSIG(p->p_xsig);
3709 } else if (WIFSIGNALED(p->p_xsig)) {
3710 reason = CLD_KILLED;
3711 status = WTERMSIG(p->p_xsig);
3712 } else {
3713 reason = CLD_EXITED;
3714 status = p->p_xexit;
3715 }
3716 /*
3717 * XXX avoid calling wakeup(p->p_pptr), the work is
3718 * done in exit1().
3719 */
3720 sigparent(p, reason, status);
3721 }
3722
3723 /*
3724 * Nonexistent system call-- signal process (may want to handle it). Flag
3725 * error in case process won't see signal immediately (blocked or ignored).
3726 */
3727 #ifndef _SYS_SYSPROTO_H_
3728 struct nosys_args {
3729 int dummy;
3730 };
3731 #endif
3732 /* ARGSUSED */
3733 int
nosys(struct thread * td,struct nosys_args * args)3734 nosys(struct thread *td, struct nosys_args *args)
3735 {
3736 return (kern_nosys(td, args->dummy));
3737 }
3738
3739 int
kern_nosys(struct thread * td,int dummy)3740 kern_nosys(struct thread *td, int dummy)
3741 {
3742 struct proc *p;
3743
3744 p = td->td_proc;
3745
3746 if (SV_PROC_FLAG(p, SV_SIGSYS) != 0 && kern_signosys) {
3747 PROC_LOCK(p);
3748 tdsignal(td, SIGSYS);
3749 PROC_UNLOCK(p);
3750 }
3751 if (kern_lognosys == 1 || kern_lognosys == 3) {
3752 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3753 td->td_sa.code);
3754 }
3755 if (kern_lognosys == 2 || kern_lognosys == 3 ||
3756 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
3757 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3758 td->td_sa.code);
3759 }
3760 return (ENOSYS);
3761 }
3762
3763 /*
3764 * Send a SIGIO or SIGURG signal to a process or process group using stored
3765 * credentials rather than those of the current process.
3766 */
3767 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)3768 pgsigio(struct sigio **sigiop, int sig, int checkctty)
3769 {
3770 ksiginfo_t ksi;
3771 struct sigio *sigio;
3772
3773 ksiginfo_init(&ksi);
3774 ksi.ksi_signo = sig;
3775 ksi.ksi_code = SI_KERNEL;
3776
3777 SIGIO_LOCK();
3778 sigio = *sigiop;
3779 if (sigio == NULL) {
3780 SIGIO_UNLOCK();
3781 return;
3782 }
3783 if (sigio->sio_pgid > 0) {
3784 PROC_LOCK(sigio->sio_proc);
3785 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3786 kern_psignal(sigio->sio_proc, sig);
3787 PROC_UNLOCK(sigio->sio_proc);
3788 } else if (sigio->sio_pgid < 0) {
3789 struct proc *p;
3790
3791 PGRP_LOCK(sigio->sio_pgrp);
3792 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3793 PROC_LOCK(p);
3794 if (p->p_state == PRS_NORMAL &&
3795 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3796 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3797 kern_psignal(p, sig);
3798 PROC_UNLOCK(p);
3799 }
3800 PGRP_UNLOCK(sigio->sio_pgrp);
3801 }
3802 SIGIO_UNLOCK();
3803 }
3804
3805 static int
filt_sigattach(struct knote * kn)3806 filt_sigattach(struct knote *kn)
3807 {
3808 struct proc *p = curproc;
3809
3810 kn->kn_ptr.p_proc = p;
3811 kn->kn_flags |= EV_CLEAR; /* automatically set */
3812
3813 knlist_add(p->p_klist, kn, 0);
3814
3815 return (0);
3816 }
3817
3818 static void
filt_sigdetach(struct knote * kn)3819 filt_sigdetach(struct knote *kn)
3820 {
3821 knlist_remove(kn->kn_knlist, kn, 0);
3822 }
3823
3824 /*
3825 * signal knotes are shared with proc knotes, so we apply a mask to
3826 * the hint in order to differentiate them from process hints. This
3827 * could be avoided by using a signal-specific knote list, but probably
3828 * isn't worth the trouble.
3829 */
3830 static int
filt_signal(struct knote * kn,long hint)3831 filt_signal(struct knote *kn, long hint)
3832 {
3833
3834 if (hint & NOTE_SIGNAL) {
3835 hint &= ~NOTE_SIGNAL;
3836
3837 if (kn->kn_id == hint)
3838 kn->kn_data++;
3839 }
3840 return (kn->kn_data != 0);
3841 }
3842
3843 struct sigacts *
sigacts_alloc(void)3844 sigacts_alloc(void)
3845 {
3846 struct sigacts *ps;
3847
3848 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3849 refcount_init(&ps->ps_refcnt, 1);
3850 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3851 return (ps);
3852 }
3853
3854 void
sigacts_free(struct sigacts * ps)3855 sigacts_free(struct sigacts *ps)
3856 {
3857
3858 if (refcount_release(&ps->ps_refcnt) == 0)
3859 return;
3860 mtx_destroy(&ps->ps_mtx);
3861 free(ps, M_SUBPROC);
3862 }
3863
3864 struct sigacts *
sigacts_hold(struct sigacts * ps)3865 sigacts_hold(struct sigacts *ps)
3866 {
3867
3868 refcount_acquire(&ps->ps_refcnt);
3869 return (ps);
3870 }
3871
3872 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3873 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3874 {
3875
3876 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3877 mtx_lock(&src->ps_mtx);
3878 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3879 mtx_unlock(&src->ps_mtx);
3880 }
3881
3882 int
sigacts_shared(struct sigacts * ps)3883 sigacts_shared(struct sigacts *ps)
3884 {
3885
3886 return (ps->ps_refcnt > 1);
3887 }
3888
3889 void
sig_drop_caught(struct proc * p)3890 sig_drop_caught(struct proc *p)
3891 {
3892 int sig;
3893 struct sigacts *ps;
3894
3895 ps = p->p_sigacts;
3896 PROC_LOCK_ASSERT(p, MA_OWNED);
3897 mtx_assert(&ps->ps_mtx, MA_OWNED);
3898 SIG_FOREACH(sig, &ps->ps_sigcatch) {
3899 sigdflt(ps, sig);
3900 if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
3901 sigqueue_delete_proc(p, sig);
3902 }
3903 }
3904
3905 static void
sigfastblock_failed(struct thread * td,bool sendsig,bool write)3906 sigfastblock_failed(struct thread *td, bool sendsig, bool write)
3907 {
3908 ksiginfo_t ksi;
3909
3910 /*
3911 * Prevent further fetches and SIGSEGVs, allowing thread to
3912 * issue syscalls despite corruption.
3913 */
3914 sigfastblock_clear(td);
3915
3916 if (!sendsig)
3917 return;
3918 ksiginfo_init_trap(&ksi);
3919 ksi.ksi_signo = SIGSEGV;
3920 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR;
3921 ksi.ksi_addr = td->td_sigblock_ptr;
3922 trapsignal(td, &ksi);
3923 }
3924
3925 static bool
sigfastblock_fetch_sig(struct thread * td,bool sendsig,uint32_t * valp)3926 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp)
3927 {
3928 uint32_t res;
3929
3930 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
3931 return (true);
3932 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) {
3933 sigfastblock_failed(td, sendsig, false);
3934 return (false);
3935 }
3936 *valp = res;
3937 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS;
3938 return (true);
3939 }
3940
3941 static void
sigfastblock_resched(struct thread * td,bool resched)3942 sigfastblock_resched(struct thread *td, bool resched)
3943 {
3944 struct proc *p;
3945
3946 if (resched) {
3947 p = td->td_proc;
3948 PROC_LOCK(p);
3949 reschedule_signals(p, td->td_sigmask, 0);
3950 PROC_UNLOCK(p);
3951 }
3952 ast_sched(td, TDA_SIG);
3953 }
3954
3955 int
sys_sigfastblock(struct thread * td,struct sigfastblock_args * uap)3956 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap)
3957 {
3958 struct proc *p;
3959 int error, res;
3960 uint32_t oldval;
3961
3962 error = 0;
3963 p = td->td_proc;
3964 switch (uap->cmd) {
3965 case SIGFASTBLOCK_SETPTR:
3966 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
3967 error = EBUSY;
3968 break;
3969 }
3970 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) {
3971 error = EINVAL;
3972 break;
3973 }
3974 td->td_pflags |= TDP_SIGFASTBLOCK;
3975 td->td_sigblock_ptr = uap->ptr;
3976 break;
3977
3978 case SIGFASTBLOCK_UNBLOCK:
3979 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
3980 error = EINVAL;
3981 break;
3982 }
3983
3984 for (;;) {
3985 res = casueword32(td->td_sigblock_ptr,
3986 SIGFASTBLOCK_PEND, &oldval, 0);
3987 if (res == -1) {
3988 error = EFAULT;
3989 sigfastblock_failed(td, false, true);
3990 break;
3991 }
3992 if (res == 0)
3993 break;
3994 MPASS(res == 1);
3995 if (oldval != SIGFASTBLOCK_PEND) {
3996 error = EBUSY;
3997 break;
3998 }
3999 error = thread_check_susp(td, false);
4000 if (error != 0)
4001 break;
4002 }
4003 if (error != 0)
4004 break;
4005
4006 /*
4007 * td_sigblock_val is cleared there, but not on a
4008 * syscall exit. The end effect is that a single
4009 * interruptible sleep, while user sigblock word is
4010 * set, might return EINTR or ERESTART to usermode
4011 * without delivering signal. All further sleeps,
4012 * until userspace clears the word and does
4013 * sigfastblock(UNBLOCK), observe current word and no
4014 * longer get interrupted. It is slight
4015 * non-conformance, with alternative to have read the
4016 * sigblock word on each syscall entry.
4017 */
4018 td->td_sigblock_val = 0;
4019
4020 /*
4021 * Rely on normal ast mechanism to deliver pending
4022 * signals to current thread. But notify others about
4023 * fake unblock.
4024 */
4025 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1);
4026
4027 break;
4028
4029 case SIGFASTBLOCK_UNSETPTR:
4030 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4031 error = EINVAL;
4032 break;
4033 }
4034 if (!sigfastblock_fetch_sig(td, false, &oldval)) {
4035 error = EFAULT;
4036 break;
4037 }
4038 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) {
4039 error = EBUSY;
4040 break;
4041 }
4042 sigfastblock_clear(td);
4043 break;
4044
4045 default:
4046 error = EINVAL;
4047 break;
4048 }
4049 return (error);
4050 }
4051
4052 void
sigfastblock_clear(struct thread * td)4053 sigfastblock_clear(struct thread *td)
4054 {
4055 bool resched;
4056
4057 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4058 return;
4059 td->td_sigblock_val = 0;
4060 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 ||
4061 SIGPENDING(td);
4062 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING);
4063 sigfastblock_resched(td, resched);
4064 }
4065
4066 void
sigfastblock_fetch(struct thread * td)4067 sigfastblock_fetch(struct thread *td)
4068 {
4069 uint32_t val;
4070
4071 (void)sigfastblock_fetch_sig(td, true, &val);
4072 }
4073
4074 static void
sigfastblock_setpend1(struct thread * td)4075 sigfastblock_setpend1(struct thread *td)
4076 {
4077 int res;
4078 uint32_t oldval;
4079
4080 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0)
4081 return;
4082 res = fueword32((void *)td->td_sigblock_ptr, &oldval);
4083 if (res == -1) {
4084 sigfastblock_failed(td, true, false);
4085 return;
4086 }
4087 for (;;) {
4088 res = casueword32(td->td_sigblock_ptr, oldval, &oldval,
4089 oldval | SIGFASTBLOCK_PEND);
4090 if (res == -1) {
4091 sigfastblock_failed(td, true, true);
4092 return;
4093 }
4094 if (res == 0) {
4095 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS;
4096 td->td_pflags &= ~TDP_SIGFASTPENDING;
4097 break;
4098 }
4099 MPASS(res == 1);
4100 if (thread_check_susp(td, false) != 0)
4101 break;
4102 }
4103 }
4104
4105 static void
sigfastblock_setpend(struct thread * td,bool resched)4106 sigfastblock_setpend(struct thread *td, bool resched)
4107 {
4108 struct proc *p;
4109
4110 sigfastblock_setpend1(td);
4111 if (resched) {
4112 p = td->td_proc;
4113 PROC_LOCK(p);
4114 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
4115 PROC_UNLOCK(p);
4116 }
4117 }
4118