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)347 sigqueue_start(void)
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 wctx.vp = tcq->tc_vp;
2660 wctx.fcred = NOCRED;
2661
2662 cdw.ctx = &wctx;
2663 cdw.write_fn = core_vn_write;
2664 cdw.extend_fn = core_vn_extend;
2665
2666 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX);
2667 tcq->tc_error = p->p_sysent->sv_coredump(td, &cdw,
2668 tcq->tc_limit, tcq->tc_flags);
2669 vn_rangelock_unlock(tcq->tc_vp, rl_cookie);
2670 }
2671
2672 static void
ptrace_syscallreq(struct thread * td,struct proc * p,struct thr_syscall_req * tsr)2673 ptrace_syscallreq(struct thread *td, struct proc *p,
2674 struct thr_syscall_req *tsr)
2675 {
2676 struct sysentvec *sv;
2677 struct sysent *se;
2678 register_t rv_saved[2];
2679 int error, nerror;
2680 int sc;
2681 bool audited, sy_thr_static;
2682
2683 sv = p->p_sysent;
2684 if (sv->sv_table == NULL || sv->sv_size < tsr->ts_sa.code) {
2685 tsr->ts_ret.sr_error = ENOSYS;
2686 return;
2687 }
2688
2689 sc = tsr->ts_sa.code;
2690 if (sc == SYS_syscall || sc == SYS___syscall) {
2691 sc = tsr->ts_sa.args[0];
2692 memmove(&tsr->ts_sa.args[0], &tsr->ts_sa.args[1],
2693 sizeof(register_t) * (tsr->ts_nargs - 1));
2694 }
2695
2696 tsr->ts_sa.callp = se = &sv->sv_table[sc];
2697
2698 VM_CNT_INC(v_syscall);
2699 td->td_pticks = 0;
2700 if (__predict_false(td->td_cowgen != atomic_load_int(
2701 &td->td_proc->p_cowgen)))
2702 thread_cow_update(td);
2703
2704 td->td_sa = tsr->ts_sa;
2705
2706 #ifdef CAPABILITY_MODE
2707 if ((se->sy_flags & SYF_CAPENABLED) == 0) {
2708 if (CAP_TRACING(td))
2709 ktrcapfail(CAPFAIL_SYSCALL, NULL);
2710 if (IN_CAPABILITY_MODE(td)) {
2711 tsr->ts_ret.sr_error = ECAPMODE;
2712 return;
2713 }
2714 }
2715 #endif
2716
2717 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2718 audited = AUDIT_SYSCALL_ENTER(sc, td) != 0;
2719
2720 if (!sy_thr_static) {
2721 error = syscall_thread_enter(td, &se);
2722 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2723 if (error != 0) {
2724 tsr->ts_ret.sr_error = error;
2725 return;
2726 }
2727 }
2728
2729 rv_saved[0] = td->td_retval[0];
2730 rv_saved[1] = td->td_retval[1];
2731 nerror = td->td_errno;
2732 td->td_retval[0] = 0;
2733 td->td_retval[1] = 0;
2734
2735 #ifdef KDTRACE_HOOKS
2736 if (se->sy_entry != 0)
2737 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_ENTRY, 0);
2738 #endif
2739 tsr->ts_ret.sr_error = se->sy_call(td, tsr->ts_sa.args);
2740 #ifdef KDTRACE_HOOKS
2741 if (se->sy_return != 0)
2742 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_RETURN,
2743 tsr->ts_ret.sr_error != 0 ? -1 : td->td_retval[0]);
2744 #endif
2745
2746 tsr->ts_ret.sr_retval[0] = td->td_retval[0];
2747 tsr->ts_ret.sr_retval[1] = td->td_retval[1];
2748 td->td_retval[0] = rv_saved[0];
2749 td->td_retval[1] = rv_saved[1];
2750 td->td_errno = nerror;
2751
2752 if (audited)
2753 AUDIT_SYSCALL_EXIT(error, td);
2754 if (!sy_thr_static)
2755 syscall_thread_exit(td, se);
2756 }
2757
2758 static void
ptrace_remotereq(struct thread * td,int flag)2759 ptrace_remotereq(struct thread *td, int flag)
2760 {
2761 struct proc *p;
2762
2763 MPASS(td == curthread);
2764 p = td->td_proc;
2765 PROC_LOCK_ASSERT(p, MA_OWNED);
2766 if ((td->td_dbgflags & flag) == 0)
2767 return;
2768 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped"));
2769 KASSERT(td->td_remotereq != NULL, ("td_remotereq is NULL"));
2770
2771 PROC_UNLOCK(p);
2772 switch (flag) {
2773 case TDB_COREDUMPREQ:
2774 ptrace_coredumpreq(td, p, td->td_remotereq);
2775 break;
2776 case TDB_SCREMOTEREQ:
2777 ptrace_syscallreq(td, p, td->td_remotereq);
2778 break;
2779 default:
2780 __unreachable();
2781 }
2782 PROC_LOCK(p);
2783
2784 MPASS((td->td_dbgflags & flag) != 0);
2785 td->td_dbgflags &= ~flag;
2786 td->td_remotereq = NULL;
2787 wakeup(p);
2788 }
2789
2790 /*
2791 * Suspend threads of the process p, either by directly setting the
2792 * inhibitor for the thread sleeping interruptibly, or by making the
2793 * thread suspend at the userspace boundary by scheduling a suspend AST.
2794 *
2795 * Returns true if some threads were suspended directly from the
2796 * sleeping state, and false if all threads are forced to process AST.
2797 */
2798 static bool
sig_suspend_threads(struct thread * td,struct proc * p)2799 sig_suspend_threads(struct thread *td, struct proc *p)
2800 {
2801 struct thread *td2;
2802 bool res;
2803
2804 PROC_LOCK_ASSERT(p, MA_OWNED);
2805 PROC_SLOCK_ASSERT(p, MA_OWNED);
2806
2807 res = false;
2808 FOREACH_THREAD_IN_PROC(p, td2) {
2809 thread_lock(td2);
2810 ast_sched_locked(td2, TDA_SUSPEND);
2811 if (TD_IS_SLEEPING(td2) && (td2->td_flags & TDF_SINTR) != 0) {
2812 if (td2->td_flags & TDF_SBDRY) {
2813 /*
2814 * Once a thread is asleep with
2815 * TDF_SBDRY and without TDF_SERESTART
2816 * or TDF_SEINTR set, it should never
2817 * become suspended due to this check.
2818 */
2819 KASSERT(!TD_IS_SUSPENDED(td2),
2820 ("thread with deferred stops suspended"));
2821 if (TD_SBDRY_INTR(td2)) {
2822 sleepq_abort(td2, TD_SBDRY_ERRNO(td2));
2823 continue;
2824 }
2825 } else if (!TD_IS_SUSPENDED(td2)) {
2826 thread_suspend_one(td2);
2827 res = true;
2828 }
2829 } else if (!TD_IS_SUSPENDED(td2)) {
2830 #ifdef SMP
2831 if (TD_IS_RUNNING(td2) && td2 != td)
2832 forward_signal(td2);
2833 #endif
2834 }
2835 thread_unlock(td2);
2836 }
2837 return (res);
2838 }
2839
2840 static void
sig_handle_first_stop(struct thread * td,struct proc * p,int sig)2841 sig_handle_first_stop(struct thread *td, struct proc *p, int sig)
2842 {
2843 if (td != NULL && (td->td_dbgflags & TDB_FSTP) == 0 &&
2844 ((p->p_flag2 & P2_PTRACE_FSTP) != 0 || p->p_xthread != NULL))
2845 return;
2846
2847 p->p_xsig = sig;
2848 p->p_xthread = td;
2849
2850 /*
2851 * If we are on sleepqueue already, let sleepqueue
2852 * code decide if it needs to go sleep after attach.
2853 */
2854 if (td != NULL && td->td_wchan == NULL)
2855 td->td_dbgflags &= ~TDB_FSTP;
2856
2857 p->p_flag2 &= ~P2_PTRACE_FSTP;
2858 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2859 if (sig_suspend_threads(td, p) && td == NULL)
2860 thread_stopped(p);
2861 }
2862
2863 /*
2864 * Stop the process for an event deemed interesting to the debugger. If si is
2865 * non-NULL, this is a signal exchange; the new signal requested by the
2866 * debugger will be returned for handling. If si is NULL, this is some other
2867 * type of interesting event. The debugger may request a signal be delivered in
2868 * that case as well, however it will be deferred until it can be handled.
2869 */
2870 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2871 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2872 {
2873 struct proc *p = td->td_proc;
2874 struct thread *td2;
2875 ksiginfo_t ksi;
2876
2877 PROC_LOCK_ASSERT(p, MA_OWNED);
2878 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2879 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2880 &p->p_mtx.lock_object, "Stopping for traced signal");
2881
2882 td->td_xsig = sig;
2883
2884 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2885 td->td_dbgflags |= TDB_XSIG;
2886 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2887 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2888 PROC_SLOCK(p);
2889 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2890 if (P_KILLED(p)) {
2891 /*
2892 * Ensure that, if we've been PT_KILLed, the
2893 * exit status reflects that. Another thread
2894 * may also be in ptracestop(), having just
2895 * received the SIGKILL, but this thread was
2896 * unsuspended first.
2897 */
2898 td->td_dbgflags &= ~TDB_XSIG;
2899 td->td_xsig = SIGKILL;
2900 p->p_ptevents = 0;
2901 break;
2902 }
2903 if (p->p_flag & P_SINGLE_EXIT &&
2904 !(td->td_dbgflags & TDB_EXIT)) {
2905 /*
2906 * Ignore ptrace stops except for thread exit
2907 * events when the process exits.
2908 */
2909 td->td_dbgflags &= ~TDB_XSIG;
2910 PROC_SUNLOCK(p);
2911 return (0);
2912 }
2913
2914 /*
2915 * Make wait(2) work. Ensure that right after the
2916 * attach, the thread which was decided to become the
2917 * leader of attach gets reported to the waiter.
2918 * Otherwise, just avoid overwriting another thread's
2919 * assignment to p_xthread. If another thread has
2920 * already set p_xthread, the current thread will get
2921 * a chance to report itself upon the next iteration.
2922 */
2923 sig_handle_first_stop(td, p, sig);
2924
2925 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2926 td->td_dbgflags &= ~TDB_STOPATFORK;
2927 }
2928 stopme:
2929 td->td_dbgflags |= TDB_SSWITCH;
2930 thread_suspend_switch(td, p);
2931 td->td_dbgflags &= ~TDB_SSWITCH;
2932 if ((td->td_dbgflags & (TDB_COREDUMPREQ |
2933 TDB_SCREMOTEREQ)) != 0) {
2934 MPASS((td->td_dbgflags & (TDB_COREDUMPREQ |
2935 TDB_SCREMOTEREQ)) !=
2936 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2937 PROC_SUNLOCK(p);
2938 ptrace_remotereq(td, td->td_dbgflags &
2939 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2940 PROC_SLOCK(p);
2941 goto stopme;
2942 }
2943 if (p->p_xthread == td)
2944 p->p_xthread = NULL;
2945 if (!(p->p_flag & P_TRACED))
2946 break;
2947 if (td->td_dbgflags & TDB_SUSPEND) {
2948 if (p->p_flag & P_SINGLE_EXIT)
2949 break;
2950 goto stopme;
2951 }
2952 }
2953 PROC_SUNLOCK(p);
2954 }
2955
2956 if (si != NULL && sig == td->td_xsig) {
2957 /* Parent wants us to take the original signal unchanged. */
2958 si->ksi_flags |= KSI_HEAD;
2959 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2960 si->ksi_signo = 0;
2961 } else if (td->td_xsig != 0) {
2962 /*
2963 * If parent wants us to take a new signal, then it will leave
2964 * it in td->td_xsig; otherwise we just look for signals again.
2965 */
2966 ksiginfo_init(&ksi);
2967 ksi.ksi_signo = td->td_xsig;
2968 ksi.ksi_flags |= KSI_PTRACE;
2969 td2 = sigtd(p, td->td_xsig, false);
2970 tdsendsignal(p, td2, td->td_xsig, &ksi);
2971 if (td != td2)
2972 return (0);
2973 }
2974
2975 return (td->td_xsig);
2976 }
2977
2978 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2979 reschedule_signals(struct proc *p, sigset_t block, int flags)
2980 {
2981 struct sigacts *ps;
2982 struct thread *td;
2983 int sig;
2984 bool fastblk, pslocked;
2985
2986 PROC_LOCK_ASSERT(p, MA_OWNED);
2987 ps = p->p_sigacts;
2988 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0;
2989 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED);
2990 if (SIGISEMPTY(p->p_siglist))
2991 return;
2992 SIGSETAND(block, p->p_siglist);
2993 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0;
2994 SIG_FOREACH(sig, &block) {
2995 td = sigtd(p, sig, fastblk);
2996
2997 /*
2998 * If sigtd() selected us despite sigfastblock is
2999 * blocking, do not activate AST or wake us, to avoid
3000 * loop in AST handler.
3001 */
3002 if (fastblk && td == curthread)
3003 continue;
3004
3005 signotify(td);
3006 if (!pslocked)
3007 mtx_lock(&ps->ps_mtx);
3008 if (p->p_flag & P_TRACED ||
3009 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
3010 !SIGISMEMBER(td->td_sigmask, sig))) {
3011 tdsigwakeup(td, sig, SIG_CATCH,
3012 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
3013 ERESTART));
3014 }
3015 if (!pslocked)
3016 mtx_unlock(&ps->ps_mtx);
3017 }
3018 }
3019
3020 void
tdsigcleanup(struct thread * td)3021 tdsigcleanup(struct thread *td)
3022 {
3023 struct proc *p;
3024 sigset_t unblocked;
3025
3026 p = td->td_proc;
3027 PROC_LOCK_ASSERT(p, MA_OWNED);
3028
3029 sigqueue_flush(&td->td_sigqueue);
3030 if (p->p_numthreads == 1)
3031 return;
3032
3033 /*
3034 * Since we cannot handle signals, notify signal post code
3035 * about this by filling the sigmask.
3036 *
3037 * Also, if needed, wake up thread(s) that do not block the
3038 * same signals as the exiting thread, since the thread might
3039 * have been selected for delivery and woken up.
3040 */
3041 SIGFILLSET(unblocked);
3042 SIGSETNAND(unblocked, td->td_sigmask);
3043 SIGFILLSET(td->td_sigmask);
3044 reschedule_signals(p, unblocked, 0);
3045
3046 }
3047
3048 static int
sigdeferstop_curr_flags(int cflags)3049 sigdeferstop_curr_flags(int cflags)
3050 {
3051
3052 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
3053 (cflags & TDF_SBDRY) != 0);
3054 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
3055 }
3056
3057 /*
3058 * Defer the delivery of SIGSTOP for the current thread, according to
3059 * the requested mode. Returns previous flags, which must be restored
3060 * by sigallowstop().
3061 *
3062 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
3063 * cleared by the current thread, which allow the lock-less read-only
3064 * accesses below.
3065 */
3066 int
sigdeferstop_impl(int mode)3067 sigdeferstop_impl(int mode)
3068 {
3069 struct thread *td;
3070 int cflags, nflags;
3071
3072 td = curthread;
3073 cflags = sigdeferstop_curr_flags(td->td_flags);
3074 switch (mode) {
3075 case SIGDEFERSTOP_NOP:
3076 nflags = cflags;
3077 break;
3078 case SIGDEFERSTOP_OFF:
3079 nflags = 0;
3080 break;
3081 case SIGDEFERSTOP_SILENT:
3082 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
3083 break;
3084 case SIGDEFERSTOP_EINTR:
3085 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
3086 break;
3087 case SIGDEFERSTOP_ERESTART:
3088 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
3089 break;
3090 default:
3091 panic("sigdeferstop: invalid mode %x", mode);
3092 break;
3093 }
3094 if (cflags == nflags)
3095 return (SIGDEFERSTOP_VAL_NCHG);
3096 thread_lock(td);
3097 td->td_flags = (td->td_flags & ~cflags) | nflags;
3098 thread_unlock(td);
3099 return (cflags);
3100 }
3101
3102 /*
3103 * Restores the STOP handling mode, typically permitting the delivery
3104 * of SIGSTOP for the current thread. This does not immediately
3105 * suspend if a stop was posted. Instead, the thread will suspend
3106 * either via ast() or a subsequent interruptible sleep.
3107 */
3108 void
sigallowstop_impl(int prev)3109 sigallowstop_impl(int prev)
3110 {
3111 struct thread *td;
3112 int cflags;
3113
3114 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
3115 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
3116 ("sigallowstop: incorrect previous mode %x", prev));
3117 td = curthread;
3118 cflags = sigdeferstop_curr_flags(td->td_flags);
3119 if (cflags != prev) {
3120 thread_lock(td);
3121 td->td_flags = (td->td_flags & ~cflags) | prev;
3122 thread_unlock(td);
3123 }
3124 }
3125
3126 enum sigstatus {
3127 SIGSTATUS_HANDLE,
3128 SIGSTATUS_HANDLED,
3129 SIGSTATUS_IGNORE,
3130 SIGSTATUS_SBDRY_STOP,
3131 };
3132
3133 /*
3134 * The thread has signal "sig" pending. Figure out what to do with it:
3135 *
3136 * _HANDLE -> the caller should handle the signal
3137 * _HANDLED -> handled internally, reload pending signal set
3138 * _IGNORE -> ignored, remove from the set of pending signals and try the
3139 * next pending signal
3140 * _SBDRY_STOP -> the signal should stop the thread but this is not
3141 * permitted in the current context
3142 */
3143 static enum sigstatus
sigprocess(struct thread * td,int sig)3144 sigprocess(struct thread *td, int sig)
3145 {
3146 struct proc *p;
3147 struct sigacts *ps;
3148 struct sigqueue *queue;
3149 ksiginfo_t ksi;
3150 int prop;
3151
3152 KASSERT(_SIG_VALID(sig), ("%s: invalid signal %d", __func__, sig));
3153
3154 p = td->td_proc;
3155 ps = p->p_sigacts;
3156 mtx_assert(&ps->ps_mtx, MA_OWNED);
3157 PROC_LOCK_ASSERT(p, MA_OWNED);
3158
3159 /*
3160 * We should allow pending but ignored signals below
3161 * if there is sigwait() active, or P_TRACED was
3162 * on when they were posted.
3163 */
3164 if (SIGISMEMBER(ps->ps_sigignore, sig) &&
3165 (p->p_flag & P_TRACED) == 0 &&
3166 (td->td_flags & TDF_SIGWAIT) == 0) {
3167 return (SIGSTATUS_IGNORE);
3168 }
3169
3170 /*
3171 * If the process is going to single-thread mode to prepare
3172 * for exit, there is no sense in delivering any signal
3173 * to usermode. Another important consequence is that
3174 * msleep(..., PCATCH, ...) now is only interruptible by a
3175 * suspend request.
3176 */
3177 if ((p->p_flag2 & P2_WEXIT) != 0)
3178 return (SIGSTATUS_IGNORE);
3179
3180 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
3181 /*
3182 * If traced, always stop.
3183 * Remove old signal from queue before the stop.
3184 * XXX shrug off debugger, it causes siginfo to
3185 * be thrown away.
3186 */
3187 queue = &td->td_sigqueue;
3188 ksiginfo_init(&ksi);
3189 if (sigqueue_get(queue, sig, &ksi) == 0) {
3190 queue = &p->p_sigqueue;
3191 sigqueue_get(queue, sig, &ksi);
3192 }
3193 td->td_si = ksi.ksi_info;
3194
3195 mtx_unlock(&ps->ps_mtx);
3196 sig = ptracestop(td, sig, &ksi);
3197 mtx_lock(&ps->ps_mtx);
3198
3199 td->td_si.si_signo = 0;
3200
3201 /*
3202 * Keep looking if the debugger discarded or
3203 * replaced the signal.
3204 */
3205 if (sig == 0)
3206 return (SIGSTATUS_HANDLED);
3207
3208 /*
3209 * If the signal became masked, re-queue it.
3210 */
3211 if (SIGISMEMBER(td->td_sigmask, sig)) {
3212 ksi.ksi_flags |= KSI_HEAD;
3213 sigqueue_add(&p->p_sigqueue, sig, &ksi);
3214 return (SIGSTATUS_HANDLED);
3215 }
3216
3217 /*
3218 * If the traced bit got turned off, requeue the signal and
3219 * reload the set of pending signals. This ensures that p_sig*
3220 * and p_sigact are consistent.
3221 */
3222 if ((p->p_flag & P_TRACED) == 0) {
3223 if ((ksi.ksi_flags & KSI_PTRACE) == 0) {
3224 ksi.ksi_flags |= KSI_HEAD;
3225 sigqueue_add(queue, sig, &ksi);
3226 }
3227 return (SIGSTATUS_HANDLED);
3228 }
3229 }
3230
3231 /*
3232 * Decide whether the signal should be returned.
3233 * Return the signal's number, or fall through
3234 * to clear it from the pending mask.
3235 */
3236 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
3237 case (intptr_t)SIG_DFL:
3238 /*
3239 * Don't take default actions on system processes.
3240 */
3241 if (p->p_pid <= 1) {
3242 #ifdef DIAGNOSTIC
3243 /*
3244 * Are you sure you want to ignore SIGSEGV
3245 * in init? XXX
3246 */
3247 printf("Process (pid %lu) got signal %d\n",
3248 (u_long)p->p_pid, sig);
3249 #endif
3250 return (SIGSTATUS_IGNORE);
3251 }
3252
3253 /*
3254 * If there is a pending stop signal to process with
3255 * default action, stop here, then clear the signal.
3256 * Traced or exiting processes should ignore stops.
3257 * Additionally, a member of an orphaned process group
3258 * should ignore tty stops.
3259 */
3260 prop = sigprop(sig);
3261 if (prop & SIGPROP_STOP) {
3262 mtx_unlock(&ps->ps_mtx);
3263 if ((p->p_flag & (P_TRACED | P_WEXIT |
3264 P_SINGLE_EXIT)) != 0 || ((p->p_pgrp->
3265 pg_flags & PGRP_ORPHANED) != 0 &&
3266 (prop & SIGPROP_TTYSTOP) != 0)) {
3267 mtx_lock(&ps->ps_mtx);
3268 return (SIGSTATUS_IGNORE);
3269 }
3270 if (TD_SBDRY_INTR(td)) {
3271 KASSERT((td->td_flags & TDF_SBDRY) != 0,
3272 ("lost TDF_SBDRY"));
3273 mtx_lock(&ps->ps_mtx);
3274 return (SIGSTATUS_SBDRY_STOP);
3275 }
3276 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
3277 &p->p_mtx.lock_object, "Catching SIGSTOP");
3278 sigqueue_delete(&td->td_sigqueue, sig);
3279 sigqueue_delete(&p->p_sigqueue, sig);
3280 p->p_flag |= P_STOPPED_SIG;
3281 p->p_xsig = sig;
3282 PROC_SLOCK(p);
3283 sig_suspend_threads(td, p);
3284 thread_suspend_switch(td, p);
3285 PROC_SUNLOCK(p);
3286 mtx_lock(&ps->ps_mtx);
3287 return (SIGSTATUS_HANDLED);
3288 } else if ((prop & SIGPROP_IGNORE) != 0 &&
3289 (td->td_flags & TDF_SIGWAIT) == 0) {
3290 /*
3291 * Default action is to ignore; drop it if
3292 * not in kern_sigtimedwait().
3293 */
3294 return (SIGSTATUS_IGNORE);
3295 } else {
3296 return (SIGSTATUS_HANDLE);
3297 }
3298
3299 case (intptr_t)SIG_IGN:
3300 if ((td->td_flags & TDF_SIGWAIT) == 0)
3301 return (SIGSTATUS_IGNORE);
3302 else
3303 return (SIGSTATUS_HANDLE);
3304
3305 default:
3306 /*
3307 * This signal has an action, let postsig() process it.
3308 */
3309 return (SIGSTATUS_HANDLE);
3310 }
3311 }
3312
3313 /*
3314 * If the current process has received a signal (should be caught or cause
3315 * termination, should interrupt current syscall), return the signal number.
3316 * Stop signals with default action are processed immediately, then cleared;
3317 * they aren't returned. This is checked after each entry to the system for
3318 * a syscall or trap (though this can usually be done without calling
3319 * issignal by checking the pending signal masks in cursig.) The normal call
3320 * sequence is
3321 *
3322 * while (sig = cursig(curthread))
3323 * postsig(sig);
3324 */
3325 static int
issignal(struct thread * td)3326 issignal(struct thread *td)
3327 {
3328 struct proc *p;
3329 sigset_t sigpending;
3330 int sig;
3331
3332 p = td->td_proc;
3333 PROC_LOCK_ASSERT(p, MA_OWNED);
3334
3335 for (;;) {
3336 sigpending = td->td_sigqueue.sq_signals;
3337 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
3338 SIGSETNAND(sigpending, td->td_sigmask);
3339
3340 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
3341 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
3342 SIG_STOPSIGMASK(sigpending);
3343 if (SIGISEMPTY(sigpending)) /* no signal to send */
3344 return (0);
3345
3346 /*
3347 * Do fast sigblock if requested by usermode. Since
3348 * we do know that there was a signal pending at this
3349 * point, set the FAST_SIGBLOCK_PEND as indicator for
3350 * usermode to perform a dummy call to
3351 * FAST_SIGBLOCK_UNBLOCK, which causes immediate
3352 * delivery of postponed pending signal.
3353 */
3354 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
3355 if (td->td_sigblock_val != 0)
3356 SIGSETNAND(sigpending, fastblock_mask);
3357 if (SIGISEMPTY(sigpending)) {
3358 td->td_pflags |= TDP_SIGFASTPENDING;
3359 return (0);
3360 }
3361 }
3362
3363 if (!pt_attach_transparent &&
3364 (p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
3365 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
3366 SIGISMEMBER(sigpending, SIGSTOP)) {
3367 /*
3368 * If debugger just attached, always consume
3369 * SIGSTOP from ptrace(PT_ATTACH) first, to
3370 * execute the debugger attach ritual in
3371 * order.
3372 */
3373 td->td_dbgflags |= TDB_FSTP;
3374 SIGEMPTYSET(sigpending);
3375 SIGADDSET(sigpending, SIGSTOP);
3376 }
3377
3378 SIG_FOREACH(sig, &sigpending) {
3379 switch (sigprocess(td, sig)) {
3380 case SIGSTATUS_HANDLE:
3381 return (sig);
3382 case SIGSTATUS_HANDLED:
3383 goto next;
3384 case SIGSTATUS_IGNORE:
3385 sigqueue_delete(&td->td_sigqueue, sig);
3386 sigqueue_delete(&p->p_sigqueue, sig);
3387 break;
3388 case SIGSTATUS_SBDRY_STOP:
3389 return (-1);
3390 }
3391 }
3392 next:;
3393 }
3394 }
3395
3396 void
thread_stopped(struct proc * p)3397 thread_stopped(struct proc *p)
3398 {
3399 int n;
3400
3401 PROC_LOCK_ASSERT(p, MA_OWNED);
3402 PROC_SLOCK_ASSERT(p, MA_OWNED);
3403 n = p->p_suspcount;
3404 if (p == curproc)
3405 n++;
3406 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
3407 PROC_SUNLOCK(p);
3408 p->p_flag &= ~P_WAITED;
3409 PROC_LOCK(p->p_pptr);
3410 childproc_stopped(p, (p->p_flag & P_TRACED) ?
3411 CLD_TRAPPED : CLD_STOPPED);
3412 PROC_UNLOCK(p->p_pptr);
3413 PROC_SLOCK(p);
3414 }
3415 }
3416
3417 /*
3418 * Take the action for the specified signal
3419 * from the current set of pending signals.
3420 */
3421 int
postsig(int sig)3422 postsig(int sig)
3423 {
3424 struct thread *td;
3425 struct proc *p;
3426 struct sigacts *ps;
3427 sig_t action;
3428 ksiginfo_t ksi;
3429 sigset_t returnmask;
3430
3431 KASSERT(sig != 0, ("postsig"));
3432
3433 td = curthread;
3434 p = td->td_proc;
3435 PROC_LOCK_ASSERT(p, MA_OWNED);
3436 ps = p->p_sigacts;
3437 mtx_assert(&ps->ps_mtx, MA_OWNED);
3438 ksiginfo_init(&ksi);
3439 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3440 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3441 return (0);
3442 ksi.ksi_signo = sig;
3443 if (ksi.ksi_code == SI_TIMER)
3444 itimer_accept(p, ksi.ksi_timerid, &ksi);
3445 action = ps->ps_sigact[_SIG_IDX(sig)];
3446 #ifdef KTRACE
3447 if (KTRPOINT(td, KTR_PSIG))
3448 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3449 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3450 #endif
3451
3452 if (action == SIG_DFL) {
3453 /*
3454 * Default action, where the default is to kill
3455 * the process. (Other cases were ignored above.)
3456 */
3457 mtx_unlock(&ps->ps_mtx);
3458 proc_td_siginfo_capture(td, &ksi.ksi_info);
3459 sigexit(td, sig);
3460 /* NOTREACHED */
3461 } else {
3462 /*
3463 * If we get here, the signal must be caught.
3464 */
3465 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3466 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3467 ("postsig action: blocked sig %d", sig));
3468
3469 /*
3470 * Set the new mask value and also defer further
3471 * occurrences of this signal.
3472 *
3473 * Special case: user has done a sigsuspend. Here the
3474 * current mask is not of interest, but rather the
3475 * mask from before the sigsuspend is what we want
3476 * restored after the signal processing is completed.
3477 */
3478 if (td->td_pflags & TDP_OLDMASK) {
3479 returnmask = td->td_oldsigmask;
3480 td->td_pflags &= ~TDP_OLDMASK;
3481 } else
3482 returnmask = td->td_sigmask;
3483
3484 if (p->p_sig == sig) {
3485 p->p_sig = 0;
3486 }
3487 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3488 postsig_done(sig, td, ps);
3489 }
3490 return (1);
3491 }
3492
3493 int
sig_ast_checksusp(struct thread * td)3494 sig_ast_checksusp(struct thread *td)
3495 {
3496 struct proc *p __diagused;
3497 int ret;
3498
3499 p = td->td_proc;
3500 PROC_LOCK_ASSERT(p, MA_OWNED);
3501
3502 if (!td_ast_pending(td, TDA_SUSPEND))
3503 return (0);
3504
3505 ret = thread_suspend_check(1);
3506 MPASS(ret == 0 || ret == EINTR || ret == ERESTART);
3507 return (ret);
3508 }
3509
3510 int
sig_ast_needsigchk(struct thread * td)3511 sig_ast_needsigchk(struct thread *td)
3512 {
3513 struct proc *p;
3514 struct sigacts *ps;
3515 int ret, sig;
3516
3517 p = td->td_proc;
3518 PROC_LOCK_ASSERT(p, MA_OWNED);
3519
3520 if (!td_ast_pending(td, TDA_SIG))
3521 return (0);
3522
3523 ps = p->p_sigacts;
3524 mtx_lock(&ps->ps_mtx);
3525 sig = cursig(td);
3526 if (sig == -1) {
3527 mtx_unlock(&ps->ps_mtx);
3528 KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY"));
3529 KASSERT(TD_SBDRY_INTR(td),
3530 ("lost TDF_SERESTART of TDF_SEINTR"));
3531 KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) !=
3532 (TDF_SEINTR | TDF_SERESTART),
3533 ("both TDF_SEINTR and TDF_SERESTART"));
3534 ret = TD_SBDRY_ERRNO(td);
3535 } else if (sig != 0) {
3536 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART;
3537 mtx_unlock(&ps->ps_mtx);
3538 } else {
3539 mtx_unlock(&ps->ps_mtx);
3540 ret = 0;
3541 }
3542
3543 /*
3544 * Do not go into sleep if this thread was the ptrace(2)
3545 * attach leader. cursig() consumed SIGSTOP from PT_ATTACH,
3546 * but we usually act on the signal by interrupting sleep, and
3547 * should do that here as well.
3548 */
3549 if ((td->td_dbgflags & TDB_FSTP) != 0) {
3550 if (ret == 0)
3551 ret = EINTR;
3552 td->td_dbgflags &= ~TDB_FSTP;
3553 }
3554
3555 return (ret);
3556 }
3557
3558 int
sig_intr(void)3559 sig_intr(void)
3560 {
3561 struct thread *td;
3562 struct proc *p;
3563 int ret;
3564
3565 td = curthread;
3566 if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND))
3567 return (0);
3568
3569 p = td->td_proc;
3570
3571 PROC_LOCK(p);
3572 ret = sig_ast_checksusp(td);
3573 if (ret == 0)
3574 ret = sig_ast_needsigchk(td);
3575 PROC_UNLOCK(p);
3576 return (ret);
3577 }
3578
3579 bool
curproc_sigkilled(void)3580 curproc_sigkilled(void)
3581 {
3582 struct thread *td;
3583 struct proc *p;
3584 struct sigacts *ps;
3585 bool res;
3586
3587 td = curthread;
3588 if (!td_ast_pending(td, TDA_SIG))
3589 return (false);
3590
3591 p = td->td_proc;
3592 PROC_LOCK(p);
3593 ps = p->p_sigacts;
3594 mtx_lock(&ps->ps_mtx);
3595 res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) ||
3596 SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL);
3597 mtx_unlock(&ps->ps_mtx);
3598 PROC_UNLOCK(p);
3599 return (res);
3600 }
3601
3602 void
proc_wkilled(struct proc * p)3603 proc_wkilled(struct proc *p)
3604 {
3605
3606 PROC_LOCK_ASSERT(p, MA_OWNED);
3607 if ((p->p_flag & P_WKILLED) == 0)
3608 p->p_flag |= P_WKILLED;
3609 }
3610
3611 /*
3612 * Kill the current process for stated reason.
3613 */
3614 void
killproc(struct proc * p,const char * why)3615 killproc(struct proc *p, const char *why)
3616 {
3617
3618 PROC_LOCK_ASSERT(p, MA_OWNED);
3619 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3620 p->p_comm);
3621 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
3622 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
3623 p->p_ucred->cr_uid, why);
3624 proc_wkilled(p);
3625 kern_psignal(p, SIGKILL);
3626 }
3627
3628 /*
3629 * Send queued SIGCHLD to parent when child process's state
3630 * is changed.
3631 */
3632 static void
sigparent(struct proc * p,int reason,int status)3633 sigparent(struct proc *p, int reason, int status)
3634 {
3635 PROC_LOCK_ASSERT(p, MA_OWNED);
3636 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3637
3638 if (p->p_ksi != NULL) {
3639 p->p_ksi->ksi_signo = SIGCHLD;
3640 p->p_ksi->ksi_code = reason;
3641 p->p_ksi->ksi_status = status;
3642 p->p_ksi->ksi_pid = p->p_pid;
3643 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3644 if (KSI_ONQ(p->p_ksi))
3645 return;
3646 }
3647
3648 /*
3649 * Do not consume p_ksi if parent is zombie, since signal is
3650 * dropped immediately. Instead, keep it since it might be
3651 * useful for reaper.
3652 */
3653 if (p->p_pptr->p_state != PRS_ZOMBIE)
3654 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3655 }
3656
3657 static void
childproc_jobstate(struct proc * p,int reason,int sig)3658 childproc_jobstate(struct proc *p, int reason, int sig)
3659 {
3660 struct sigacts *ps;
3661
3662 PROC_LOCK_ASSERT(p, MA_OWNED);
3663 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3664
3665 /*
3666 * Wake up parent sleeping in kern_wait(), also send
3667 * SIGCHLD to parent, but SIGCHLD does not guarantee
3668 * that parent will awake, because parent may masked
3669 * the signal.
3670 */
3671 p->p_pptr->p_flag |= P_STATCHILD;
3672 wakeup(p->p_pptr);
3673
3674 ps = p->p_pptr->p_sigacts;
3675 mtx_lock(&ps->ps_mtx);
3676 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3677 mtx_unlock(&ps->ps_mtx);
3678 sigparent(p, reason, sig);
3679 } else
3680 mtx_unlock(&ps->ps_mtx);
3681 }
3682
3683 void
childproc_stopped(struct proc * p,int reason)3684 childproc_stopped(struct proc *p, int reason)
3685 {
3686
3687 childproc_jobstate(p, reason, p->p_xsig);
3688 }
3689
3690 void
childproc_continued(struct proc * p)3691 childproc_continued(struct proc *p)
3692 {
3693 PROC_LOCK_ASSERT(p, MA_OWNED);
3694 p->p_flag |= P_CONTINUED;
3695 p->p_xsig = SIGCONT;
3696 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3697 }
3698
3699 void
childproc_exited(struct proc * p)3700 childproc_exited(struct proc *p)
3701 {
3702 int reason, status;
3703
3704 if (WCOREDUMP(p->p_xsig)) {
3705 reason = CLD_DUMPED;
3706 status = WTERMSIG(p->p_xsig);
3707 } else if (WIFSIGNALED(p->p_xsig)) {
3708 reason = CLD_KILLED;
3709 status = WTERMSIG(p->p_xsig);
3710 } else {
3711 reason = CLD_EXITED;
3712 status = p->p_xexit;
3713 }
3714 /*
3715 * XXX avoid calling wakeup(p->p_pptr), the work is
3716 * done in exit1().
3717 */
3718 sigparent(p, reason, status);
3719 }
3720
3721 /*
3722 * Nonexistent system call-- signal process (may want to handle it). Flag
3723 * error in case process won't see signal immediately (blocked or ignored).
3724 */
3725 #ifndef _SYS_SYSPROTO_H_
3726 struct nosys_args {
3727 int dummy;
3728 };
3729 #endif
3730 /* ARGSUSED */
3731 int
nosys(struct thread * td,struct nosys_args * args)3732 nosys(struct thread *td, struct nosys_args *args)
3733 {
3734 return (kern_nosys(td, args->dummy));
3735 }
3736
3737 int
kern_nosys(struct thread * td,int dummy)3738 kern_nosys(struct thread *td, int dummy)
3739 {
3740 struct proc *p;
3741
3742 p = td->td_proc;
3743
3744 if (SV_PROC_FLAG(p, SV_SIGSYS) != 0 && kern_signosys) {
3745 PROC_LOCK(p);
3746 tdsignal(td, SIGSYS);
3747 PROC_UNLOCK(p);
3748 }
3749 if (kern_lognosys == 1 || kern_lognosys == 3) {
3750 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3751 td->td_sa.code);
3752 }
3753 if (kern_lognosys == 2 || kern_lognosys == 3 ||
3754 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
3755 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
3756 td->td_sa.code);
3757 }
3758 return (ENOSYS);
3759 }
3760
3761 /*
3762 * Send a SIGIO or SIGURG signal to a process or process group using stored
3763 * credentials rather than those of the current process.
3764 */
3765 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)3766 pgsigio(struct sigio **sigiop, int sig, int checkctty)
3767 {
3768 ksiginfo_t ksi;
3769 struct sigio *sigio;
3770
3771 ksiginfo_init(&ksi);
3772 ksi.ksi_signo = sig;
3773 ksi.ksi_code = SI_KERNEL;
3774
3775 SIGIO_LOCK();
3776 sigio = *sigiop;
3777 if (sigio == NULL) {
3778 SIGIO_UNLOCK();
3779 return;
3780 }
3781 if (sigio->sio_pgid > 0) {
3782 PROC_LOCK(sigio->sio_proc);
3783 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
3784 kern_psignal(sigio->sio_proc, sig);
3785 PROC_UNLOCK(sigio->sio_proc);
3786 } else if (sigio->sio_pgid < 0) {
3787 struct proc *p;
3788
3789 PGRP_LOCK(sigio->sio_pgrp);
3790 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
3791 PROC_LOCK(p);
3792 if (p->p_state == PRS_NORMAL &&
3793 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
3794 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
3795 kern_psignal(p, sig);
3796 PROC_UNLOCK(p);
3797 }
3798 PGRP_UNLOCK(sigio->sio_pgrp);
3799 }
3800 SIGIO_UNLOCK();
3801 }
3802
3803 static int
filt_sigattach(struct knote * kn)3804 filt_sigattach(struct knote *kn)
3805 {
3806 struct proc *p = curproc;
3807
3808 kn->kn_ptr.p_proc = p;
3809 kn->kn_flags |= EV_CLEAR; /* automatically set */
3810
3811 knlist_add(p->p_klist, kn, 0);
3812
3813 return (0);
3814 }
3815
3816 static void
filt_sigdetach(struct knote * kn)3817 filt_sigdetach(struct knote *kn)
3818 {
3819 knlist_remove(kn->kn_knlist, kn, 0);
3820 }
3821
3822 /*
3823 * signal knotes are shared with proc knotes, so we apply a mask to
3824 * the hint in order to differentiate them from process hints. This
3825 * could be avoided by using a signal-specific knote list, but probably
3826 * isn't worth the trouble.
3827 */
3828 static int
filt_signal(struct knote * kn,long hint)3829 filt_signal(struct knote *kn, long hint)
3830 {
3831
3832 if (hint & NOTE_SIGNAL) {
3833 hint &= ~NOTE_SIGNAL;
3834
3835 if (kn->kn_id == hint)
3836 kn->kn_data++;
3837 }
3838 return (kn->kn_data != 0);
3839 }
3840
3841 struct sigacts *
sigacts_alloc(void)3842 sigacts_alloc(void)
3843 {
3844 struct sigacts *ps;
3845
3846 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
3847 refcount_init(&ps->ps_refcnt, 1);
3848 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
3849 return (ps);
3850 }
3851
3852 void
sigacts_free(struct sigacts * ps)3853 sigacts_free(struct sigacts *ps)
3854 {
3855
3856 if (refcount_release(&ps->ps_refcnt) == 0)
3857 return;
3858 mtx_destroy(&ps->ps_mtx);
3859 free(ps, M_SUBPROC);
3860 }
3861
3862 struct sigacts *
sigacts_hold(struct sigacts * ps)3863 sigacts_hold(struct sigacts *ps)
3864 {
3865
3866 refcount_acquire(&ps->ps_refcnt);
3867 return (ps);
3868 }
3869
3870 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)3871 sigacts_copy(struct sigacts *dest, struct sigacts *src)
3872 {
3873
3874 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
3875 mtx_lock(&src->ps_mtx);
3876 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
3877 mtx_unlock(&src->ps_mtx);
3878 }
3879
3880 int
sigacts_shared(struct sigacts * ps)3881 sigacts_shared(struct sigacts *ps)
3882 {
3883
3884 return (ps->ps_refcnt > 1);
3885 }
3886
3887 void
sig_drop_caught(struct proc * p)3888 sig_drop_caught(struct proc *p)
3889 {
3890 int sig;
3891 struct sigacts *ps;
3892
3893 ps = p->p_sigacts;
3894 PROC_LOCK_ASSERT(p, MA_OWNED);
3895 mtx_assert(&ps->ps_mtx, MA_OWNED);
3896 SIG_FOREACH(sig, &ps->ps_sigcatch) {
3897 sigdflt(ps, sig);
3898 if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
3899 sigqueue_delete_proc(p, sig);
3900 }
3901 }
3902
3903 static void
sigfastblock_failed(struct thread * td,bool sendsig,bool write)3904 sigfastblock_failed(struct thread *td, bool sendsig, bool write)
3905 {
3906 ksiginfo_t ksi;
3907
3908 /*
3909 * Prevent further fetches and SIGSEGVs, allowing thread to
3910 * issue syscalls despite corruption.
3911 */
3912 sigfastblock_clear(td);
3913
3914 if (!sendsig)
3915 return;
3916 ksiginfo_init_trap(&ksi);
3917 ksi.ksi_signo = SIGSEGV;
3918 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR;
3919 ksi.ksi_addr = td->td_sigblock_ptr;
3920 trapsignal(td, &ksi);
3921 }
3922
3923 static bool
sigfastblock_fetch_sig(struct thread * td,bool sendsig,uint32_t * valp)3924 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp)
3925 {
3926 uint32_t res;
3927
3928 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
3929 return (true);
3930 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) {
3931 sigfastblock_failed(td, sendsig, false);
3932 return (false);
3933 }
3934 *valp = res;
3935 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS;
3936 return (true);
3937 }
3938
3939 static void
sigfastblock_resched(struct thread * td,bool resched)3940 sigfastblock_resched(struct thread *td, bool resched)
3941 {
3942 struct proc *p;
3943
3944 if (resched) {
3945 p = td->td_proc;
3946 PROC_LOCK(p);
3947 reschedule_signals(p, td->td_sigmask, 0);
3948 PROC_UNLOCK(p);
3949 }
3950 ast_sched(td, TDA_SIG);
3951 }
3952
3953 int
sys_sigfastblock(struct thread * td,struct sigfastblock_args * uap)3954 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap)
3955 {
3956 struct proc *p;
3957 int error, res;
3958 uint32_t oldval;
3959
3960 error = 0;
3961 p = td->td_proc;
3962 switch (uap->cmd) {
3963 case SIGFASTBLOCK_SETPTR:
3964 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
3965 error = EBUSY;
3966 break;
3967 }
3968 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) {
3969 error = EINVAL;
3970 break;
3971 }
3972 td->td_pflags |= TDP_SIGFASTBLOCK;
3973 td->td_sigblock_ptr = uap->ptr;
3974 break;
3975
3976 case SIGFASTBLOCK_UNBLOCK:
3977 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
3978 error = EINVAL;
3979 break;
3980 }
3981
3982 for (;;) {
3983 res = casueword32(td->td_sigblock_ptr,
3984 SIGFASTBLOCK_PEND, &oldval, 0);
3985 if (res == -1) {
3986 error = EFAULT;
3987 sigfastblock_failed(td, false, true);
3988 break;
3989 }
3990 if (res == 0)
3991 break;
3992 MPASS(res == 1);
3993 if (oldval != SIGFASTBLOCK_PEND) {
3994 error = EBUSY;
3995 break;
3996 }
3997 error = thread_check_susp(td, false);
3998 if (error != 0)
3999 break;
4000 }
4001 if (error != 0)
4002 break;
4003
4004 /*
4005 * td_sigblock_val is cleared there, but not on a
4006 * syscall exit. The end effect is that a single
4007 * interruptible sleep, while user sigblock word is
4008 * set, might return EINTR or ERESTART to usermode
4009 * without delivering signal. All further sleeps,
4010 * until userspace clears the word and does
4011 * sigfastblock(UNBLOCK), observe current word and no
4012 * longer get interrupted. It is slight
4013 * non-conformance, with alternative to have read the
4014 * sigblock word on each syscall entry.
4015 */
4016 td->td_sigblock_val = 0;
4017
4018 /*
4019 * Rely on normal ast mechanism to deliver pending
4020 * signals to current thread. But notify others about
4021 * fake unblock.
4022 */
4023 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1);
4024
4025 break;
4026
4027 case SIGFASTBLOCK_UNSETPTR:
4028 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4029 error = EINVAL;
4030 break;
4031 }
4032 if (!sigfastblock_fetch_sig(td, false, &oldval)) {
4033 error = EFAULT;
4034 break;
4035 }
4036 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) {
4037 error = EBUSY;
4038 break;
4039 }
4040 sigfastblock_clear(td);
4041 break;
4042
4043 default:
4044 error = EINVAL;
4045 break;
4046 }
4047 return (error);
4048 }
4049
4050 void
sigfastblock_clear(struct thread * td)4051 sigfastblock_clear(struct thread *td)
4052 {
4053 bool resched;
4054
4055 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4056 return;
4057 td->td_sigblock_val = 0;
4058 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 ||
4059 SIGPENDING(td);
4060 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING);
4061 sigfastblock_resched(td, resched);
4062 }
4063
4064 void
sigfastblock_fetch(struct thread * td)4065 sigfastblock_fetch(struct thread *td)
4066 {
4067 uint32_t val;
4068
4069 (void)sigfastblock_fetch_sig(td, true, &val);
4070 }
4071
4072 static void
sigfastblock_setpend1(struct thread * td)4073 sigfastblock_setpend1(struct thread *td)
4074 {
4075 int res;
4076 uint32_t oldval;
4077
4078 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0)
4079 return;
4080 res = fueword32((void *)td->td_sigblock_ptr, &oldval);
4081 if (res == -1) {
4082 sigfastblock_failed(td, true, false);
4083 return;
4084 }
4085 for (;;) {
4086 res = casueword32(td->td_sigblock_ptr, oldval, &oldval,
4087 oldval | SIGFASTBLOCK_PEND);
4088 if (res == -1) {
4089 sigfastblock_failed(td, true, true);
4090 return;
4091 }
4092 if (res == 0) {
4093 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS;
4094 td->td_pflags &= ~TDP_SIGFASTPENDING;
4095 break;
4096 }
4097 MPASS(res == 1);
4098 if (thread_check_susp(td, false) != 0)
4099 break;
4100 }
4101 }
4102
4103 static void
sigfastblock_setpend(struct thread * td,bool resched)4104 sigfastblock_setpend(struct thread *td, bool resched)
4105 {
4106 struct proc *p;
4107
4108 sigfastblock_setpend1(td);
4109 if (resched) {
4110 p = td->td_proc;
4111 PROC_LOCK(p);
4112 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
4113 PROC_UNLOCK(p);
4114 }
4115 }
4116