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/compressor.h>
49 #include <sys/condvar.h>
50 #include <sys/devctl.h>
51 #include <sys/event.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/unistd.h>
84 #include <sys/vmmeter.h>
85 #include <sys/wait.h>
86 #include <vm/vm.h>
87 #include <vm/vm_extern.h>
88 #include <vm/uma.h>
89
90 #include <machine/cpu.h>
91
92 #include <security/audit/audit.h>
93
94 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
95
96 SDT_PROVIDER_DECLARE(proc);
97 SDT_PROBE_DEFINE3(proc, , , signal__send,
98 "struct thread *", "struct proc *", "int");
99 SDT_PROBE_DEFINE2(proc, , , signal__clear,
100 "int", "ksiginfo_t *");
101 SDT_PROBE_DEFINE3(proc, , , signal__discard,
102 "struct thread *", "struct proc *", "int");
103
104 static int coredump(struct thread *);
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 void 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, bool ext);
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_logsigexit = 1;
130 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
131 &kern_logsigexit, 0,
132 "Log processes quitting on abnormal signals to syslog(3)");
133
134 static int kern_forcesigexit = 1;
135 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
136 &kern_forcesigexit, 0, "Force trap signal to be handled");
137
138 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
139 "POSIX real time signal");
140
141 static int max_pending_per_proc = 128;
142 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
143 &max_pending_per_proc, 0, "Max pending signals per proc");
144
145 static int preallocate_siginfo = 1024;
146 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
147 &preallocate_siginfo, 0, "Preallocated signal memory size");
148
149 static int signal_overflow = 0;
150 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
151 &signal_overflow, 0, "Number of signals overflew");
152
153 static int signal_alloc_fail = 0;
154 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
155 &signal_alloc_fail, 0, "signals failed to be allocated");
156
157 static int kern_lognosys = 0;
158 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
159 "Log invalid syscalls");
160
161 static int kern_signosys = 1;
162 SYSCTL_INT(_kern, OID_AUTO, signosys, CTLFLAG_RWTUN, &kern_signosys, 0,
163 "Send SIGSYS on return from invalid syscall");
164
165 __read_frequently bool sigfastblock_fetch_always = false;
166 SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN,
167 &sigfastblock_fetch_always, 0,
168 "Fetch sigfastblock word on each syscall entry for proper "
169 "blocking semantic");
170
171 static bool kern_sig_discard_ign = true;
172 SYSCTL_BOOL(_kern, OID_AUTO, sig_discard_ign, CTLFLAG_RWTUN,
173 &kern_sig_discard_ign, 0,
174 "Discard ignored signals on delivery, otherwise queue them to "
175 "the target queue");
176
177 static bool pt_attach_transparent = true;
178 SYSCTL_BOOL(_debug, OID_AUTO, ptrace_attach_transparent, CTLFLAG_RWTUN,
179 &pt_attach_transparent, 0,
180 "Hide wakes from PT_ATTACH on interruptible sleeps");
181
182 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
183
184 /*
185 * Policy -- Can ucred cr1 send SIGIO to process cr2?
186 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
187 * in the right situations.
188 */
189 #define CANSIGIO(cr1, cr2) \
190 ((cr1)->cr_uid == 0 || \
191 (cr1)->cr_ruid == (cr2)->cr_ruid || \
192 (cr1)->cr_uid == (cr2)->cr_ruid || \
193 (cr1)->cr_ruid == (cr2)->cr_uid || \
194 (cr1)->cr_uid == (cr2)->cr_uid)
195
196 static int sugid_coredump;
197 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN,
198 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
199
200 static int capmode_coredump;
201 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN,
202 &capmode_coredump, 0, "Allow processes in capability mode to dump core");
203
204 static int do_coredump = 1;
205 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
206 &do_coredump, 0, "Enable/Disable coredumps");
207
208 static int set_core_nodump_flag = 0;
209 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
210 0, "Enable setting the NODUMP flag on coredump files");
211
212 static int coredump_devctl = 0;
213 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
214 0, "Generate a devctl notification when processes coredump");
215
216 /*
217 * Signal properties and actions.
218 * The array below categorizes the signals and their default actions
219 * according to the following properties:
220 */
221 #define SIGPROP_KILL 0x01 /* terminates process by default */
222 #define SIGPROP_CORE 0x02 /* ditto and coredumps */
223 #define SIGPROP_STOP 0x04 /* suspend process */
224 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */
225 #define SIGPROP_IGNORE 0x10 /* ignore by default */
226 #define SIGPROP_CONT 0x20 /* continue if suspended */
227
228 static const int sigproptbl[NSIG] = {
229 [SIGHUP] = SIGPROP_KILL,
230 [SIGINT] = SIGPROP_KILL,
231 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE,
232 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE,
233 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE,
234 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE,
235 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE,
236 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE,
237 [SIGKILL] = SIGPROP_KILL,
238 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE,
239 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE,
240 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE,
241 [SIGPIPE] = SIGPROP_KILL,
242 [SIGALRM] = SIGPROP_KILL,
243 [SIGTERM] = SIGPROP_KILL,
244 [SIGURG] = SIGPROP_IGNORE,
245 [SIGSTOP] = SIGPROP_STOP,
246 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP,
247 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT,
248 [SIGCHLD] = SIGPROP_IGNORE,
249 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP,
250 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP,
251 [SIGIO] = SIGPROP_IGNORE,
252 [SIGXCPU] = SIGPROP_KILL,
253 [SIGXFSZ] = SIGPROP_KILL,
254 [SIGVTALRM] = SIGPROP_KILL,
255 [SIGPROF] = SIGPROP_KILL,
256 [SIGWINCH] = SIGPROP_IGNORE,
257 [SIGINFO] = SIGPROP_IGNORE,
258 [SIGUSR1] = SIGPROP_KILL,
259 [SIGUSR2] = SIGPROP_KILL,
260 };
261
262 #define _SIG_FOREACH_ADVANCE(i, set) ({ \
263 int __found; \
264 for (;;) { \
265 if (__bits != 0) { \
266 int __sig = ffs(__bits); \
267 __bits &= ~(1u << (__sig - 1)); \
268 sig = __i * sizeof((set)->__bits[0]) * NBBY + __sig; \
269 __found = 1; \
270 break; \
271 } \
272 if (++__i == _SIG_WORDS) { \
273 __found = 0; \
274 break; \
275 } \
276 __bits = (set)->__bits[__i]; \
277 } \
278 __found != 0; \
279 })
280
281 #define SIG_FOREACH(i, set) \
282 for (int32_t __i = -1, __bits = 0; \
283 _SIG_FOREACH_ADVANCE(i, set); ) \
284
285 static sigset_t fastblock_mask;
286
287 static void
ast_sig(struct thread * td,int tda)288 ast_sig(struct thread *td, int tda)
289 {
290 struct proc *p;
291 int old_boundary, sig;
292 bool resched_sigs;
293
294 p = td->td_proc;
295
296 #ifdef DIAGNOSTIC
297 if (p->p_numthreads == 1 && (tda & (TDAI(TDA_SIG) |
298 TDAI(TDA_AST))) == 0) {
299 PROC_LOCK(p);
300 thread_lock(td);
301 /*
302 * Note that TDA_SIG should be re-read from
303 * td_ast, since signal might have been delivered
304 * after we cleared td_flags above. This is one of
305 * the reason for looping check for AST condition.
306 * See comment in userret() about P_PPWAIT.
307 */
308 if ((p->p_flag & P_PPWAIT) == 0 &&
309 (td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
310 if (SIGPENDING(td) && ((tda | td->td_ast) &
311 (TDAI(TDA_SIG) | TDAI(TDA_AST))) == 0) {
312 thread_unlock(td); /* fix dumps */
313 panic(
314 "failed2 to set signal flags for ast p %p "
315 "td %p tda %#x td_ast %#x fl %#x",
316 p, td, tda, td->td_ast, td->td_flags);
317 }
318 }
319 thread_unlock(td);
320 PROC_UNLOCK(p);
321 }
322 #endif
323
324 /*
325 * Check for signals. Unlocked reads of p_pendingcnt or
326 * p_siglist might cause process-directed signal to be handled
327 * later.
328 */
329 if ((tda & TDAI(TDA_SIG)) != 0 || p->p_pendingcnt > 0 ||
330 !SIGISEMPTY(p->p_siglist)) {
331 sigfastblock_fetch(td);
332 PROC_LOCK(p);
333 old_boundary = ~TDB_BOUNDARY | (td->td_dbgflags & TDB_BOUNDARY);
334 td->td_dbgflags |= TDB_BOUNDARY;
335 mtx_lock(&p->p_sigacts->ps_mtx);
336 while ((sig = cursig(td)) != 0) {
337 KASSERT(sig >= 0, ("sig %d", sig));
338 postsig(sig);
339 }
340 mtx_unlock(&p->p_sigacts->ps_mtx);
341 td->td_dbgflags &= old_boundary;
342 PROC_UNLOCK(p);
343 resched_sigs = true;
344 } else {
345 resched_sigs = false;
346 }
347
348 /*
349 * Handle deferred update of the fast sigblock value, after
350 * the postsig() loop was performed.
351 */
352 sigfastblock_setpend(td, resched_sigs);
353
354 /*
355 * Clear td_sa.code: signal to ptrace that syscall arguments
356 * are unavailable after this point. This AST handler is the
357 * last chance for ptracestop() to signal the tracer before
358 * the tracee returns to userspace.
359 */
360 td->td_sa.code = 0;
361 }
362
363 static void
ast_sigsuspend(struct thread * td,int tda __unused)364 ast_sigsuspend(struct thread *td, int tda __unused)
365 {
366 MPASS((td->td_pflags & TDP_OLDMASK) != 0);
367 td->td_pflags &= ~TDP_OLDMASK;
368 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
369 }
370
371 static void
sigqueue_start(void)372 sigqueue_start(void)
373 {
374 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
375 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
376 uma_prealloc(ksiginfo_zone, preallocate_siginfo);
377 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
378 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
379 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
380 SIGFILLSET(fastblock_mask);
381 SIG_CANTMASK(fastblock_mask);
382 ast_register(TDA_SIG, ASTR_UNCOND, 0, ast_sig);
383
384 /*
385 * TDA_PSELECT is for the case where the signal mask should be restored
386 * before delivering any signals so that we do not deliver any that are
387 * blocked by the normal thread mask. It is mutually exclusive with
388 * TDA_SIGSUSPEND, which should be used if we *do* want to deliver
389 * signals that are normally blocked, e.g., if it interrupted our sleep.
390 */
391 ast_register(TDA_PSELECT, ASTR_ASTF_REQUIRED | ASTR_TDP,
392 TDP_OLDMASK, ast_sigsuspend);
393 ast_register(TDA_SIGSUSPEND, ASTR_ASTF_REQUIRED | ASTR_TDP,
394 TDP_OLDMASK, ast_sigsuspend);
395 }
396
397 ksiginfo_t *
ksiginfo_alloc(int mwait)398 ksiginfo_alloc(int mwait)
399 {
400 MPASS(mwait == M_WAITOK || mwait == M_NOWAIT);
401
402 if (ksiginfo_zone == NULL)
403 return (NULL);
404 return (uma_zalloc(ksiginfo_zone, mwait | M_ZERO));
405 }
406
407 void
ksiginfo_free(ksiginfo_t * ksi)408 ksiginfo_free(ksiginfo_t *ksi)
409 {
410 uma_zfree(ksiginfo_zone, ksi);
411 }
412
413 static __inline bool
ksiginfo_tryfree(ksiginfo_t * ksi)414 ksiginfo_tryfree(ksiginfo_t *ksi)
415 {
416 if ((ksi->ksi_flags & KSI_EXT) == 0) {
417 uma_zfree(ksiginfo_zone, ksi);
418 return (true);
419 }
420 return (false);
421 }
422
423 void
sigqueue_init(sigqueue_t * list,struct proc * p)424 sigqueue_init(sigqueue_t *list, struct proc *p)
425 {
426 SIGEMPTYSET(list->sq_signals);
427 SIGEMPTYSET(list->sq_kill);
428 SIGEMPTYSET(list->sq_ptrace);
429 TAILQ_INIT(&list->sq_list);
430 list->sq_proc = p;
431 list->sq_flags = SQ_INIT;
432 }
433
434 /*
435 * Get a signal's ksiginfo.
436 * Return:
437 * 0 - signal not found
438 * others - signal number
439 */
440 static int
sigqueue_get(sigqueue_t * sq,int signo,ksiginfo_t * si)441 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
442 {
443 struct proc *p = sq->sq_proc;
444 struct ksiginfo *ksi, *next;
445 int count = 0;
446
447 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
448
449 if (!SIGISMEMBER(sq->sq_signals, signo))
450 return (0);
451
452 if (SIGISMEMBER(sq->sq_ptrace, signo)) {
453 count++;
454 SIGDELSET(sq->sq_ptrace, signo);
455 si->ksi_flags |= KSI_PTRACE;
456 }
457 if (SIGISMEMBER(sq->sq_kill, signo)) {
458 count++;
459 if (count == 1)
460 SIGDELSET(sq->sq_kill, signo);
461 }
462
463 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
464 if (ksi->ksi_signo == signo) {
465 if (count == 0) {
466 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
467 ksi->ksi_sigq = NULL;
468 ksiginfo_copy(ksi, si);
469 if (ksiginfo_tryfree(ksi) && p != NULL)
470 p->p_pendingcnt--;
471 }
472 if (++count > 1)
473 break;
474 }
475 }
476
477 if (count <= 1)
478 SIGDELSET(sq->sq_signals, signo);
479 si->ksi_signo = signo;
480 return (signo);
481 }
482
483 void
sigqueue_take(ksiginfo_t * ksi)484 sigqueue_take(ksiginfo_t *ksi)
485 {
486 struct ksiginfo *kp;
487 struct proc *p;
488 sigqueue_t *sq;
489
490 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
491 return;
492
493 p = sq->sq_proc;
494 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
495 ksi->ksi_sigq = NULL;
496 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
497 p->p_pendingcnt--;
498
499 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
500 kp = TAILQ_NEXT(kp, ksi_link)) {
501 if (kp->ksi_signo == ksi->ksi_signo)
502 break;
503 }
504 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
505 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
506 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
507 }
508
509 static int
sigqueue_add(sigqueue_t * sq,int signo,ksiginfo_t * si)510 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
511 {
512 struct proc *p = sq->sq_proc;
513 struct ksiginfo *ksi;
514 int ret = 0;
515
516 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
517
518 /*
519 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
520 * for these signals.
521 */
522 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
523 SIGADDSET(sq->sq_kill, signo);
524 goto out_set_bit;
525 }
526
527 /* directly insert the ksi, don't copy it */
528 if (si->ksi_flags & KSI_INS) {
529 if (si->ksi_flags & KSI_HEAD)
530 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
531 else
532 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
533 si->ksi_sigq = sq;
534 goto out_set_bit;
535 }
536
537 if (__predict_false(ksiginfo_zone == NULL)) {
538 SIGADDSET(sq->sq_kill, signo);
539 goto out_set_bit;
540 }
541
542 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
543 signal_overflow++;
544 ret = EAGAIN;
545 } else if ((ksi = ksiginfo_alloc(M_NOWAIT)) == NULL) {
546 signal_alloc_fail++;
547 ret = EAGAIN;
548 } else {
549 if (p != NULL)
550 p->p_pendingcnt++;
551 ksiginfo_copy(si, ksi);
552 ksi->ksi_signo = signo;
553 if (si->ksi_flags & KSI_HEAD)
554 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
555 else
556 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
557 ksi->ksi_sigq = sq;
558 }
559
560 if (ret != 0) {
561 if ((si->ksi_flags & KSI_PTRACE) != 0) {
562 SIGADDSET(sq->sq_ptrace, signo);
563 ret = 0;
564 goto out_set_bit;
565 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
566 (si->ksi_flags & KSI_SIGQ) == 0) {
567 SIGADDSET(sq->sq_kill, signo);
568 ret = 0;
569 goto out_set_bit;
570 }
571 return (ret);
572 }
573
574 out_set_bit:
575 SIGADDSET(sq->sq_signals, signo);
576 return (ret);
577 }
578
579 void
sigqueue_flush(sigqueue_t * sq)580 sigqueue_flush(sigqueue_t *sq)
581 {
582 struct proc *p = sq->sq_proc;
583 ksiginfo_t *ksi;
584
585 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
586
587 if (p != NULL)
588 PROC_LOCK_ASSERT(p, MA_OWNED);
589
590 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
591 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
592 ksi->ksi_sigq = NULL;
593 if (ksiginfo_tryfree(ksi) && p != NULL)
594 p->p_pendingcnt--;
595 }
596
597 SIGEMPTYSET(sq->sq_signals);
598 SIGEMPTYSET(sq->sq_kill);
599 SIGEMPTYSET(sq->sq_ptrace);
600 }
601
602 static void
sigqueue_move_set(sigqueue_t * src,sigqueue_t * dst,const sigset_t * set)603 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
604 {
605 sigset_t tmp;
606 struct proc *p1, *p2;
607 ksiginfo_t *ksi, *next;
608
609 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
610 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
611 p1 = src->sq_proc;
612 p2 = dst->sq_proc;
613 /* Move siginfo to target list */
614 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
615 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
616 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
617 if (p1 != NULL)
618 p1->p_pendingcnt--;
619 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
620 ksi->ksi_sigq = dst;
621 if (p2 != NULL)
622 p2->p_pendingcnt++;
623 }
624 }
625
626 /* Move pending bits to target list */
627 tmp = src->sq_kill;
628 SIGSETAND(tmp, *set);
629 SIGSETOR(dst->sq_kill, tmp);
630 SIGSETNAND(src->sq_kill, tmp);
631
632 tmp = src->sq_ptrace;
633 SIGSETAND(tmp, *set);
634 SIGSETOR(dst->sq_ptrace, tmp);
635 SIGSETNAND(src->sq_ptrace, tmp);
636
637 tmp = src->sq_signals;
638 SIGSETAND(tmp, *set);
639 SIGSETOR(dst->sq_signals, tmp);
640 SIGSETNAND(src->sq_signals, tmp);
641 }
642
643 #if 0
644 static void
645 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
646 {
647 sigset_t set;
648
649 SIGEMPTYSET(set);
650 SIGADDSET(set, signo);
651 sigqueue_move_set(src, dst, &set);
652 }
653 #endif
654
655 static void
sigqueue_delete_set(sigqueue_t * sq,const sigset_t * set)656 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
657 {
658 struct proc *p = sq->sq_proc;
659 ksiginfo_t *ksi, *next;
660
661 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
662
663 /* Remove siginfo queue */
664 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
665 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
666 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
667 ksi->ksi_sigq = NULL;
668 if (ksiginfo_tryfree(ksi) && p != NULL)
669 p->p_pendingcnt--;
670 }
671 }
672 SIGSETNAND(sq->sq_kill, *set);
673 SIGSETNAND(sq->sq_ptrace, *set);
674 SIGSETNAND(sq->sq_signals, *set);
675 }
676
677 void
sigqueue_delete(sigqueue_t * sq,int signo)678 sigqueue_delete(sigqueue_t *sq, int signo)
679 {
680 sigset_t set;
681
682 SIGEMPTYSET(set);
683 SIGADDSET(set, signo);
684 sigqueue_delete_set(sq, &set);
685 }
686
687 /* Remove a set of signals for a process */
688 static void
sigqueue_delete_set_proc(struct proc * p,const sigset_t * set)689 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
690 {
691 sigqueue_t worklist;
692 struct thread *td0;
693
694 PROC_LOCK_ASSERT(p, MA_OWNED);
695
696 sigqueue_init(&worklist, NULL);
697 sigqueue_move_set(&p->p_sigqueue, &worklist, set);
698
699 FOREACH_THREAD_IN_PROC(p, td0)
700 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
701
702 sigqueue_flush(&worklist);
703 }
704
705 void
sigqueue_delete_proc(struct proc * p,int signo)706 sigqueue_delete_proc(struct proc *p, int signo)
707 {
708 sigset_t set;
709
710 SIGEMPTYSET(set);
711 SIGADDSET(set, signo);
712 sigqueue_delete_set_proc(p, &set);
713 }
714
715 static void
sigqueue_delete_stopmask_proc(struct proc * p)716 sigqueue_delete_stopmask_proc(struct proc *p)
717 {
718 sigset_t set;
719
720 SIGEMPTYSET(set);
721 SIGADDSET(set, SIGSTOP);
722 SIGADDSET(set, SIGTSTP);
723 SIGADDSET(set, SIGTTIN);
724 SIGADDSET(set, SIGTTOU);
725 sigqueue_delete_set_proc(p, &set);
726 }
727
728 /*
729 * Determine signal that should be delivered to thread td, the current
730 * thread, 0 if none. If there is a pending stop signal with default
731 * action, the process stops in issignal().
732 */
733 int
cursig(struct thread * td)734 cursig(struct thread *td)
735 {
736 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
737 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
738 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
739 return (SIGPENDING(td) ? issignal(td) : 0);
740 }
741
742 /*
743 * Arrange for ast() to handle unmasked pending signals on return to user
744 * mode. This must be called whenever a signal is added to td_sigqueue or
745 * unmasked in td_sigmask.
746 */
747 void
signotify(struct thread * td)748 signotify(struct thread *td)
749 {
750
751 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
752
753 if (SIGPENDING(td))
754 ast_sched(td, TDA_SIG);
755 }
756
757 /*
758 * Returns 1 (true) if altstack is configured for the thread, and the
759 * passed stack bottom address falls into the altstack range. Handles
760 * the 43 compat special case where the alt stack size is zero.
761 */
762 int
sigonstack(size_t sp)763 sigonstack(size_t sp)
764 {
765 struct thread *td;
766
767 td = curthread;
768 if ((td->td_pflags & TDP_ALTSTACK) == 0)
769 return (0);
770 #if defined(COMPAT_43)
771 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0)
772 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0);
773 #endif
774 return (sp >= (size_t)td->td_sigstk.ss_sp &&
775 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp);
776 }
777
778 static __inline int
sigprop(int sig)779 sigprop(int sig)
780 {
781
782 if (sig > 0 && sig < nitems(sigproptbl))
783 return (sigproptbl[sig]);
784 return (0);
785 }
786
787 static bool
sigact_flag_test(const struct sigaction * act,int flag)788 sigact_flag_test(const struct sigaction *act, int flag)
789 {
790
791 /*
792 * SA_SIGINFO is reset when signal disposition is set to
793 * ignore or default. Other flags are kept according to user
794 * settings.
795 */
796 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
797 ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
798 (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
799 }
800
801 /*
802 * kern_sigaction
803 * sigaction
804 * freebsd4_sigaction
805 * osigaction
806 */
807 int
kern_sigaction(struct thread * td,int sig,const struct sigaction * act,struct sigaction * oact,int flags)808 kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
809 struct sigaction *oact, int flags)
810 {
811 struct sigacts *ps;
812 struct proc *p = td->td_proc;
813
814 if (!_SIG_VALID(sig))
815 return (EINVAL);
816 if (act != NULL && act->sa_handler != SIG_DFL &&
817 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
818 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
819 SA_NOCLDWAIT | SA_SIGINFO)) != 0)
820 return (EINVAL);
821
822 PROC_LOCK(p);
823 ps = p->p_sigacts;
824 mtx_lock(&ps->ps_mtx);
825 if (oact) {
826 memset(oact, 0, sizeof(*oact));
827 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
828 if (SIGISMEMBER(ps->ps_sigonstack, sig))
829 oact->sa_flags |= SA_ONSTACK;
830 if (!SIGISMEMBER(ps->ps_sigintr, sig))
831 oact->sa_flags |= SA_RESTART;
832 if (SIGISMEMBER(ps->ps_sigreset, sig))
833 oact->sa_flags |= SA_RESETHAND;
834 if (SIGISMEMBER(ps->ps_signodefer, sig))
835 oact->sa_flags |= SA_NODEFER;
836 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
837 oact->sa_flags |= SA_SIGINFO;
838 oact->sa_sigaction =
839 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
840 } else
841 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
842 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
843 oact->sa_flags |= SA_NOCLDSTOP;
844 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
845 oact->sa_flags |= SA_NOCLDWAIT;
846 }
847 if (act) {
848 if ((sig == SIGKILL || sig == SIGSTOP) &&
849 act->sa_handler != SIG_DFL) {
850 mtx_unlock(&ps->ps_mtx);
851 PROC_UNLOCK(p);
852 return (EINVAL);
853 }
854
855 /*
856 * Change setting atomically.
857 */
858
859 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
860 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
861 if (sigact_flag_test(act, SA_SIGINFO)) {
862 ps->ps_sigact[_SIG_IDX(sig)] =
863 (__sighandler_t *)act->sa_sigaction;
864 SIGADDSET(ps->ps_siginfo, sig);
865 } else {
866 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
867 SIGDELSET(ps->ps_siginfo, sig);
868 }
869 if (!sigact_flag_test(act, SA_RESTART))
870 SIGADDSET(ps->ps_sigintr, sig);
871 else
872 SIGDELSET(ps->ps_sigintr, sig);
873 if (sigact_flag_test(act, SA_ONSTACK))
874 SIGADDSET(ps->ps_sigonstack, sig);
875 else
876 SIGDELSET(ps->ps_sigonstack, sig);
877 if (sigact_flag_test(act, SA_RESETHAND))
878 SIGADDSET(ps->ps_sigreset, sig);
879 else
880 SIGDELSET(ps->ps_sigreset, sig);
881 if (sigact_flag_test(act, SA_NODEFER))
882 SIGADDSET(ps->ps_signodefer, sig);
883 else
884 SIGDELSET(ps->ps_signodefer, sig);
885 if (sig == SIGCHLD) {
886 if (act->sa_flags & SA_NOCLDSTOP)
887 ps->ps_flag |= PS_NOCLDSTOP;
888 else
889 ps->ps_flag &= ~PS_NOCLDSTOP;
890 if (act->sa_flags & SA_NOCLDWAIT) {
891 /*
892 * Paranoia: since SA_NOCLDWAIT is implemented
893 * by reparenting the dying child to PID 1 (and
894 * trust it to reap the zombie), PID 1 itself
895 * is forbidden to set SA_NOCLDWAIT.
896 */
897 if (p->p_pid == 1)
898 ps->ps_flag &= ~PS_NOCLDWAIT;
899 else
900 ps->ps_flag |= PS_NOCLDWAIT;
901 } else
902 ps->ps_flag &= ~PS_NOCLDWAIT;
903 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
904 ps->ps_flag |= PS_CLDSIGIGN;
905 else
906 ps->ps_flag &= ~PS_CLDSIGIGN;
907 }
908 /*
909 * Set bit in ps_sigignore for signals that are set to SIG_IGN,
910 * and for signals set to SIG_DFL where the default is to
911 * ignore. However, don't put SIGCONT in ps_sigignore, as we
912 * have to restart the process.
913 */
914 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
915 (sigprop(sig) & SIGPROP_IGNORE &&
916 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
917 /* never to be seen again */
918 sigqueue_delete_proc(p, sig);
919 if (sig != SIGCONT)
920 /* easier in psignal */
921 SIGADDSET(ps->ps_sigignore, sig);
922 SIGDELSET(ps->ps_sigcatch, sig);
923 } else {
924 SIGDELSET(ps->ps_sigignore, sig);
925 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
926 SIGDELSET(ps->ps_sigcatch, sig);
927 else
928 SIGADDSET(ps->ps_sigcatch, sig);
929 }
930 #ifdef COMPAT_FREEBSD4
931 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
932 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
933 (flags & KSA_FREEBSD4) == 0)
934 SIGDELSET(ps->ps_freebsd4, sig);
935 else
936 SIGADDSET(ps->ps_freebsd4, sig);
937 #endif
938 #ifdef COMPAT_43
939 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
940 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
941 (flags & KSA_OSIGSET) == 0)
942 SIGDELSET(ps->ps_osigset, sig);
943 else
944 SIGADDSET(ps->ps_osigset, sig);
945 #endif
946 }
947 mtx_unlock(&ps->ps_mtx);
948 PROC_UNLOCK(p);
949 return (0);
950 }
951
952 #ifndef _SYS_SYSPROTO_H_
953 struct sigaction_args {
954 int sig;
955 struct sigaction *act;
956 struct sigaction *oact;
957 };
958 #endif
959 int
sys_sigaction(struct thread * td,struct sigaction_args * uap)960 sys_sigaction(struct thread *td, struct sigaction_args *uap)
961 {
962 struct sigaction act, oact;
963 struct sigaction *actp, *oactp;
964 int error;
965
966 actp = (uap->act != NULL) ? &act : NULL;
967 oactp = (uap->oact != NULL) ? &oact : NULL;
968 if (actp) {
969 error = copyin(uap->act, actp, sizeof(act));
970 if (error)
971 return (error);
972 }
973 error = kern_sigaction(td, uap->sig, actp, oactp, 0);
974 if (oactp && !error)
975 error = copyout(oactp, uap->oact, sizeof(oact));
976 return (error);
977 }
978
979 #ifdef COMPAT_FREEBSD4
980 #ifndef _SYS_SYSPROTO_H_
981 struct freebsd4_sigaction_args {
982 int sig;
983 struct sigaction *act;
984 struct sigaction *oact;
985 };
986 #endif
987 int
freebsd4_sigaction(struct thread * td,struct freebsd4_sigaction_args * uap)988 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
989 {
990 struct sigaction act, oact;
991 struct sigaction *actp, *oactp;
992 int error;
993
994 actp = (uap->act != NULL) ? &act : NULL;
995 oactp = (uap->oact != NULL) ? &oact : NULL;
996 if (actp) {
997 error = copyin(uap->act, actp, sizeof(act));
998 if (error)
999 return (error);
1000 }
1001 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
1002 if (oactp && !error)
1003 error = copyout(oactp, uap->oact, sizeof(oact));
1004 return (error);
1005 }
1006 #endif /* COMAPT_FREEBSD4 */
1007
1008 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1009 #ifndef _SYS_SYSPROTO_H_
1010 struct osigaction_args {
1011 int signum;
1012 struct osigaction *nsa;
1013 struct osigaction *osa;
1014 };
1015 #endif
1016 int
osigaction(struct thread * td,struct osigaction_args * uap)1017 osigaction(struct thread *td, struct osigaction_args *uap)
1018 {
1019 struct osigaction sa;
1020 struct sigaction nsa, osa;
1021 struct sigaction *nsap, *osap;
1022 int error;
1023
1024 if (uap->signum <= 0 || uap->signum >= ONSIG)
1025 return (EINVAL);
1026
1027 nsap = (uap->nsa != NULL) ? &nsa : NULL;
1028 osap = (uap->osa != NULL) ? &osa : NULL;
1029
1030 if (nsap) {
1031 error = copyin(uap->nsa, &sa, sizeof(sa));
1032 if (error)
1033 return (error);
1034 nsap->sa_handler = sa.sa_handler;
1035 nsap->sa_flags = sa.sa_flags;
1036 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
1037 }
1038 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1039 if (osap && !error) {
1040 sa.sa_handler = osap->sa_handler;
1041 sa.sa_flags = osap->sa_flags;
1042 SIG2OSIG(osap->sa_mask, sa.sa_mask);
1043 error = copyout(&sa, uap->osa, sizeof(sa));
1044 }
1045 return (error);
1046 }
1047
1048 #if !defined(__i386__)
1049 /* Avoid replicating the same stub everywhere */
1050 int
osigreturn(struct thread * td,struct osigreturn_args * uap)1051 osigreturn(struct thread *td, struct osigreturn_args *uap)
1052 {
1053
1054 return (nosys(td, (struct nosys_args *)uap));
1055 }
1056 #endif
1057 #endif /* COMPAT_43 */
1058
1059 /*
1060 * Initialize signal state for process 0;
1061 * set to ignore signals that are ignored by default.
1062 */
1063 void
siginit(struct proc * p)1064 siginit(struct proc *p)
1065 {
1066 int i;
1067 struct sigacts *ps;
1068
1069 PROC_LOCK(p);
1070 ps = p->p_sigacts;
1071 mtx_lock(&ps->ps_mtx);
1072 for (i = 1; i <= NSIG; i++) {
1073 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) {
1074 SIGADDSET(ps->ps_sigignore, i);
1075 }
1076 }
1077 mtx_unlock(&ps->ps_mtx);
1078 PROC_UNLOCK(p);
1079 }
1080
1081 /*
1082 * Reset specified signal to the default disposition.
1083 */
1084 static void
sigdflt(struct sigacts * ps,int sig)1085 sigdflt(struct sigacts *ps, int sig)
1086 {
1087
1088 mtx_assert(&ps->ps_mtx, MA_OWNED);
1089 SIGDELSET(ps->ps_sigcatch, sig);
1090 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT)
1091 SIGADDSET(ps->ps_sigignore, sig);
1092 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1093 SIGDELSET(ps->ps_siginfo, sig);
1094 }
1095
1096 /*
1097 * Reset signals for an exec of the specified process.
1098 */
1099 void
execsigs(struct proc * p)1100 execsigs(struct proc *p)
1101 {
1102 struct sigacts *ps;
1103 struct thread *td;
1104
1105 /*
1106 * Reset caught signals. Held signals remain held
1107 * through td_sigmask (unless they were caught,
1108 * and are now ignored by default).
1109 */
1110 PROC_LOCK_ASSERT(p, MA_OWNED);
1111 ps = p->p_sigacts;
1112 mtx_lock(&ps->ps_mtx);
1113 sig_drop_caught(p);
1114
1115 /*
1116 * Reset stack state to the user stack.
1117 * Clear set of signals caught on the signal stack.
1118 */
1119 td = curthread;
1120 MPASS(td->td_proc == p);
1121 td->td_sigstk.ss_flags = SS_DISABLE;
1122 td->td_sigstk.ss_size = 0;
1123 td->td_sigstk.ss_sp = 0;
1124 td->td_pflags &= ~TDP_ALTSTACK;
1125 /*
1126 * Reset no zombies if child dies flag as Solaris does.
1127 */
1128 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
1129 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
1130 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
1131 mtx_unlock(&ps->ps_mtx);
1132 }
1133
1134 /*
1135 * kern_sigprocmask()
1136 *
1137 * Manipulate signal mask.
1138 */
1139 int
kern_sigprocmask(struct thread * td,int how,sigset_t * set,sigset_t * oset,int flags)1140 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
1141 int flags)
1142 {
1143 sigset_t new_block, oset1;
1144 struct proc *p;
1145 int error;
1146
1147 p = td->td_proc;
1148 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
1149 PROC_LOCK_ASSERT(p, MA_OWNED);
1150 else
1151 PROC_LOCK(p);
1152 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
1153 ? MA_OWNED : MA_NOTOWNED);
1154 if (oset != NULL)
1155 *oset = td->td_sigmask;
1156
1157 error = 0;
1158 if (set != NULL) {
1159 switch (how) {
1160 case SIG_BLOCK:
1161 SIG_CANTMASK(*set);
1162 oset1 = td->td_sigmask;
1163 SIGSETOR(td->td_sigmask, *set);
1164 new_block = td->td_sigmask;
1165 SIGSETNAND(new_block, oset1);
1166 break;
1167 case SIG_UNBLOCK:
1168 SIGSETNAND(td->td_sigmask, *set);
1169 signotify(td);
1170 goto out;
1171 case SIG_SETMASK:
1172 SIG_CANTMASK(*set);
1173 oset1 = td->td_sigmask;
1174 if (flags & SIGPROCMASK_OLD)
1175 SIGSETLO(td->td_sigmask, *set);
1176 else
1177 td->td_sigmask = *set;
1178 new_block = td->td_sigmask;
1179 SIGSETNAND(new_block, oset1);
1180 signotify(td);
1181 break;
1182 default:
1183 error = EINVAL;
1184 goto out;
1185 }
1186
1187 /*
1188 * The new_block set contains signals that were not previously
1189 * blocked, but are blocked now.
1190 *
1191 * In case we block any signal that was not previously blocked
1192 * for td, and process has the signal pending, try to schedule
1193 * signal delivery to some thread that does not block the
1194 * signal, possibly waking it up.
1195 */
1196 if (p->p_numthreads != 1)
1197 reschedule_signals(p, new_block, flags);
1198 }
1199
1200 out:
1201 if (!(flags & SIGPROCMASK_PROC_LOCKED))
1202 PROC_UNLOCK(p);
1203 return (error);
1204 }
1205
1206 #ifndef _SYS_SYSPROTO_H_
1207 struct sigprocmask_args {
1208 int how;
1209 const sigset_t *set;
1210 sigset_t *oset;
1211 };
1212 #endif
1213 int
sys_sigprocmask(struct thread * td,struct sigprocmask_args * uap)1214 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
1215 {
1216 sigset_t set, oset;
1217 sigset_t *setp, *osetp;
1218 int error;
1219
1220 setp = (uap->set != NULL) ? &set : NULL;
1221 osetp = (uap->oset != NULL) ? &oset : NULL;
1222 if (setp) {
1223 error = copyin(uap->set, setp, sizeof(set));
1224 if (error)
1225 return (error);
1226 }
1227 error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
1228 if (osetp && !error) {
1229 error = copyout(osetp, uap->oset, sizeof(oset));
1230 }
1231 return (error);
1232 }
1233
1234 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1235 #ifndef _SYS_SYSPROTO_H_
1236 struct osigprocmask_args {
1237 int how;
1238 osigset_t mask;
1239 };
1240 #endif
1241 int
osigprocmask(struct thread * td,struct osigprocmask_args * uap)1242 osigprocmask(struct thread *td, struct osigprocmask_args *uap)
1243 {
1244 sigset_t set, oset;
1245 int error;
1246
1247 OSIG2SIG(uap->mask, set);
1248 error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
1249 SIG2OSIG(oset, td->td_retval[0]);
1250 return (error);
1251 }
1252 #endif /* COMPAT_43 */
1253
1254 int
sys_sigwait(struct thread * td,struct sigwait_args * uap)1255 sys_sigwait(struct thread *td, struct sigwait_args *uap)
1256 {
1257 ksiginfo_t ksi;
1258 sigset_t set;
1259 int error;
1260
1261 error = copyin(uap->set, &set, sizeof(set));
1262 if (error) {
1263 td->td_retval[0] = error;
1264 return (0);
1265 }
1266
1267 error = kern_sigtimedwait(td, set, &ksi, NULL);
1268 if (error) {
1269 /*
1270 * sigwait() function shall not return EINTR, but
1271 * the syscall does. Non-ancient libc provides the
1272 * wrapper which hides EINTR. Otherwise, EINTR return
1273 * is used by libthr to handle required cancellation
1274 * point in the sigwait().
1275 */
1276 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
1277 return (ERESTART);
1278 td->td_retval[0] = error;
1279 return (0);
1280 }
1281
1282 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
1283 td->td_retval[0] = error;
1284 return (0);
1285 }
1286
1287 int
sys_sigtimedwait(struct thread * td,struct sigtimedwait_args * uap)1288 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
1289 {
1290 struct timespec ts;
1291 struct timespec *timeout;
1292 sigset_t set;
1293 ksiginfo_t ksi;
1294 int error;
1295
1296 if (uap->timeout) {
1297 error = copyin(uap->timeout, &ts, sizeof(ts));
1298 if (error)
1299 return (error);
1300
1301 timeout = &ts;
1302 } else
1303 timeout = NULL;
1304
1305 error = copyin(uap->set, &set, sizeof(set));
1306 if (error)
1307 return (error);
1308
1309 error = kern_sigtimedwait(td, set, &ksi, timeout);
1310 if (error)
1311 return (error);
1312
1313 if (uap->info)
1314 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1315
1316 if (error == 0)
1317 td->td_retval[0] = ksi.ksi_signo;
1318 return (error);
1319 }
1320
1321 int
sys_sigwaitinfo(struct thread * td,struct sigwaitinfo_args * uap)1322 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
1323 {
1324 ksiginfo_t ksi;
1325 sigset_t set;
1326 int error;
1327
1328 error = copyin(uap->set, &set, sizeof(set));
1329 if (error)
1330 return (error);
1331
1332 error = kern_sigtimedwait(td, set, &ksi, NULL);
1333 if (error)
1334 return (error);
1335
1336 if (uap->info)
1337 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
1338
1339 if (error == 0)
1340 td->td_retval[0] = ksi.ksi_signo;
1341 return (error);
1342 }
1343
1344 static void
proc_td_siginfo_capture(struct thread * td,siginfo_t * si)1345 proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
1346 {
1347 struct thread *thr;
1348
1349 FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
1350 if (thr == td)
1351 thr->td_si = *si;
1352 else
1353 thr->td_si.si_signo = 0;
1354 }
1355 }
1356
1357 int
kern_sigtimedwait(struct thread * td,sigset_t waitset,ksiginfo_t * ksi,struct timespec * timeout)1358 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
1359 struct timespec *timeout)
1360 {
1361 struct sigacts *ps;
1362 sigset_t saved_mask, new_block;
1363 struct proc *p;
1364 int error, sig, timevalid = 0;
1365 sbintime_t sbt, precision, tsbt;
1366 struct timespec ts;
1367 bool traced;
1368
1369 p = td->td_proc;
1370 error = 0;
1371 traced = false;
1372
1373 /* Ensure the sigfastblock value is up to date. */
1374 sigfastblock_fetch(td);
1375
1376 if (timeout != NULL) {
1377 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
1378 timevalid = 1;
1379 ts = *timeout;
1380 if (ts.tv_sec < INT32_MAX / 2) {
1381 tsbt = tstosbt(ts);
1382 precision = tsbt;
1383 precision >>= tc_precexp;
1384 if (TIMESEL(&sbt, tsbt))
1385 sbt += tc_tick_sbt;
1386 sbt += tsbt;
1387 } else
1388 precision = sbt = 0;
1389 }
1390 } else
1391 precision = sbt = 0;
1392 ksiginfo_init(ksi);
1393 /* Some signals can not be waited for. */
1394 SIG_CANTMASK(waitset);
1395 ps = p->p_sigacts;
1396 PROC_LOCK(p);
1397 saved_mask = td->td_sigmask;
1398 SIGSETNAND(td->td_sigmask, waitset);
1399 if ((p->p_sysent->sv_flags & SV_SIG_DISCIGN) != 0 ||
1400 !kern_sig_discard_ign) {
1401 thread_lock(td);
1402 td->td_flags |= TDF_SIGWAIT;
1403 thread_unlock(td);
1404 }
1405 for (;;) {
1406 mtx_lock(&ps->ps_mtx);
1407 sig = cursig(td);
1408 mtx_unlock(&ps->ps_mtx);
1409 KASSERT(sig >= 0, ("sig %d", sig));
1410 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
1411 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
1412 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
1413 error = 0;
1414 break;
1415 }
1416 }
1417
1418 if (error != 0)
1419 break;
1420
1421 /*
1422 * POSIX says this must be checked after looking for pending
1423 * signals.
1424 */
1425 if (timeout != NULL && !timevalid) {
1426 error = EINVAL;
1427 break;
1428 }
1429
1430 if (traced) {
1431 error = EINTR;
1432 break;
1433 }
1434
1435 error = msleep_sbt(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH,
1436 "sigwait", sbt, precision, C_ABSOLUTE);
1437
1438 /* The syscalls can not be restarted. */
1439 if (error == ERESTART)
1440 error = EINTR;
1441
1442 /*
1443 * If PTRACE_SCE or PTRACE_SCX were set after
1444 * userspace entered the syscall, return spurious
1445 * EINTR after wait was done. Only do this as last
1446 * resort after rechecking for possible queued signals
1447 * and expired timeouts.
1448 */
1449 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0)
1450 traced = true;
1451 }
1452 thread_lock(td);
1453 td->td_flags &= ~TDF_SIGWAIT;
1454 thread_unlock(td);
1455
1456 new_block = saved_mask;
1457 SIGSETNAND(new_block, td->td_sigmask);
1458 td->td_sigmask = saved_mask;
1459 /*
1460 * Fewer signals can be delivered to us, reschedule signal
1461 * notification.
1462 */
1463 if (p->p_numthreads != 1)
1464 reschedule_signals(p, new_block, 0);
1465
1466 if (error == 0) {
1467 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
1468
1469 if (ksi->ksi_code == SI_TIMER)
1470 itimer_accept(p, ksi->ksi_timerid, ksi);
1471
1472 #ifdef KTRACE
1473 if (KTRPOINT(td, KTR_PSIG)) {
1474 sig_t action;
1475
1476 mtx_lock(&ps->ps_mtx);
1477 action = ps->ps_sigact[_SIG_IDX(sig)];
1478 mtx_unlock(&ps->ps_mtx);
1479 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
1480 }
1481 #endif
1482 if (sig == SIGKILL) {
1483 proc_td_siginfo_capture(td, &ksi->ksi_info);
1484 sigexit(td, sig);
1485 }
1486 }
1487 PROC_UNLOCK(p);
1488 return (error);
1489 }
1490
1491 #ifndef _SYS_SYSPROTO_H_
1492 struct sigpending_args {
1493 sigset_t *set;
1494 };
1495 #endif
1496 int
sys_sigpending(struct thread * td,struct sigpending_args * uap)1497 sys_sigpending(struct thread *td, struct sigpending_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 return (copyout(&pending, uap->set, sizeof(sigset_t)));
1507 }
1508
1509 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1510 #ifndef _SYS_SYSPROTO_H_
1511 struct osigpending_args {
1512 int dummy;
1513 };
1514 #endif
1515 int
osigpending(struct thread * td,struct osigpending_args * uap)1516 osigpending(struct thread *td, struct osigpending_args *uap)
1517 {
1518 struct proc *p = td->td_proc;
1519 sigset_t pending;
1520
1521 PROC_LOCK(p);
1522 pending = p->p_sigqueue.sq_signals;
1523 SIGSETOR(pending, td->td_sigqueue.sq_signals);
1524 PROC_UNLOCK(p);
1525 SIG2OSIG(pending, td->td_retval[0]);
1526 return (0);
1527 }
1528 #endif /* COMPAT_43 */
1529
1530 #if defined(COMPAT_43)
1531 /*
1532 * Generalized interface signal handler, 4.3-compatible.
1533 */
1534 #ifndef _SYS_SYSPROTO_H_
1535 struct osigvec_args {
1536 int signum;
1537 struct sigvec *nsv;
1538 struct sigvec *osv;
1539 };
1540 #endif
1541 /* ARGSUSED */
1542 int
osigvec(struct thread * td,struct osigvec_args * uap)1543 osigvec(struct thread *td, struct osigvec_args *uap)
1544 {
1545 struct sigvec vec;
1546 struct sigaction nsa, osa;
1547 struct sigaction *nsap, *osap;
1548 int error;
1549
1550 if (uap->signum <= 0 || uap->signum >= ONSIG)
1551 return (EINVAL);
1552 nsap = (uap->nsv != NULL) ? &nsa : NULL;
1553 osap = (uap->osv != NULL) ? &osa : NULL;
1554 if (nsap) {
1555 error = copyin(uap->nsv, &vec, sizeof(vec));
1556 if (error)
1557 return (error);
1558 nsap->sa_handler = vec.sv_handler;
1559 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
1560 nsap->sa_flags = vec.sv_flags;
1561 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
1562 }
1563 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
1564 if (osap && !error) {
1565 vec.sv_handler = osap->sa_handler;
1566 SIG2OSIG(osap->sa_mask, vec.sv_mask);
1567 vec.sv_flags = osap->sa_flags;
1568 vec.sv_flags &= ~SA_NOCLDWAIT;
1569 vec.sv_flags ^= SA_RESTART;
1570 error = copyout(&vec, uap->osv, sizeof(vec));
1571 }
1572 return (error);
1573 }
1574
1575 #ifndef _SYS_SYSPROTO_H_
1576 struct osigblock_args {
1577 int mask;
1578 };
1579 #endif
1580 int
osigblock(struct thread * td,struct osigblock_args * uap)1581 osigblock(struct thread *td, struct osigblock_args *uap)
1582 {
1583 sigset_t set, oset;
1584
1585 OSIG2SIG(uap->mask, set);
1586 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
1587 SIG2OSIG(oset, td->td_retval[0]);
1588 return (0);
1589 }
1590
1591 #ifndef _SYS_SYSPROTO_H_
1592 struct osigsetmask_args {
1593 int mask;
1594 };
1595 #endif
1596 int
osigsetmask(struct thread * td,struct osigsetmask_args * uap)1597 osigsetmask(struct thread *td, struct osigsetmask_args *uap)
1598 {
1599 sigset_t set, oset;
1600
1601 OSIG2SIG(uap->mask, set);
1602 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
1603 SIG2OSIG(oset, td->td_retval[0]);
1604 return (0);
1605 }
1606 #endif /* COMPAT_43 */
1607
1608 /*
1609 * Suspend calling thread until signal, providing mask to be set in the
1610 * meantime.
1611 */
1612 #ifndef _SYS_SYSPROTO_H_
1613 struct sigsuspend_args {
1614 const sigset_t *sigmask;
1615 };
1616 #endif
1617 /* ARGSUSED */
1618 int
sys_sigsuspend(struct thread * td,struct sigsuspend_args * uap)1619 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
1620 {
1621 sigset_t mask;
1622 int error;
1623
1624 error = copyin(uap->sigmask, &mask, sizeof(mask));
1625 if (error)
1626 return (error);
1627 return (kern_sigsuspend(td, mask));
1628 }
1629
1630 int
kern_sigsuspend(struct thread * td,sigset_t mask)1631 kern_sigsuspend(struct thread *td, sigset_t mask)
1632 {
1633 struct proc *p = td->td_proc;
1634 int has_sig, sig;
1635
1636 /* Ensure the sigfastblock value is up to date. */
1637 sigfastblock_fetch(td);
1638
1639 /*
1640 * When returning from sigsuspend, we want
1641 * the old mask to be restored after the
1642 * signal handler has finished. Thus, we
1643 * save it here and mark the sigacts structure
1644 * to indicate this.
1645 */
1646 PROC_LOCK(p);
1647 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
1648 SIGPROCMASK_PROC_LOCKED);
1649 td->td_pflags |= TDP_OLDMASK;
1650 ast_sched(td, TDA_SIGSUSPEND);
1651
1652 /*
1653 * Process signals now. Otherwise, we can get spurious wakeup
1654 * due to signal entered process queue, but delivered to other
1655 * thread. But sigsuspend should return only on signal
1656 * delivery.
1657 */
1658 (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
1659 for (has_sig = 0; !has_sig;) {
1660 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
1661 0) == 0)
1662 /* void */;
1663 thread_suspend_check(0);
1664 mtx_lock(&p->p_sigacts->ps_mtx);
1665 while ((sig = cursig(td)) != 0) {
1666 KASSERT(sig >= 0, ("sig %d", sig));
1667 has_sig += postsig(sig);
1668 }
1669 mtx_unlock(&p->p_sigacts->ps_mtx);
1670
1671 /*
1672 * If PTRACE_SCE or PTRACE_SCX were set after
1673 * userspace entered the syscall, return spurious
1674 * EINTR.
1675 */
1676 if ((p->p_ptevents & PTRACE_SYSCALL) != 0)
1677 has_sig += 1;
1678 }
1679 PROC_UNLOCK(p);
1680 td->td_errno = EINTR;
1681 td->td_pflags |= TDP_NERRNO;
1682 return (EJUSTRETURN);
1683 }
1684
1685 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
1686 /*
1687 * Compatibility sigsuspend call for old binaries. Note nonstandard calling
1688 * convention: libc stub passes mask, not pointer, to save a copyin.
1689 */
1690 #ifndef _SYS_SYSPROTO_H_
1691 struct osigsuspend_args {
1692 osigset_t mask;
1693 };
1694 #endif
1695 /* ARGSUSED */
1696 int
osigsuspend(struct thread * td,struct osigsuspend_args * uap)1697 osigsuspend(struct thread *td, struct osigsuspend_args *uap)
1698 {
1699 sigset_t mask;
1700
1701 OSIG2SIG(uap->mask, mask);
1702 return (kern_sigsuspend(td, mask));
1703 }
1704 #endif /* COMPAT_43 */
1705
1706 #if defined(COMPAT_43)
1707 #ifndef _SYS_SYSPROTO_H_
1708 struct osigstack_args {
1709 struct sigstack *nss;
1710 struct sigstack *oss;
1711 };
1712 #endif
1713 /* ARGSUSED */
1714 int
osigstack(struct thread * td,struct osigstack_args * uap)1715 osigstack(struct thread *td, struct osigstack_args *uap)
1716 {
1717 struct sigstack nss, oss;
1718 int error = 0;
1719
1720 if (uap->nss != NULL) {
1721 error = copyin(uap->nss, &nss, sizeof(nss));
1722 if (error)
1723 return (error);
1724 }
1725 oss.ss_sp = td->td_sigstk.ss_sp;
1726 oss.ss_onstack = sigonstack(cpu_getstack(td));
1727 if (uap->nss != NULL) {
1728 td->td_sigstk.ss_sp = nss.ss_sp;
1729 td->td_sigstk.ss_size = 0;
1730 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
1731 td->td_pflags |= TDP_ALTSTACK;
1732 }
1733 if (uap->oss != NULL)
1734 error = copyout(&oss, uap->oss, sizeof(oss));
1735
1736 return (error);
1737 }
1738 #endif /* COMPAT_43 */
1739
1740 #ifndef _SYS_SYSPROTO_H_
1741 struct sigaltstack_args {
1742 stack_t *ss;
1743 stack_t *oss;
1744 };
1745 #endif
1746 /* ARGSUSED */
1747 int
sys_sigaltstack(struct thread * td,struct sigaltstack_args * uap)1748 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
1749 {
1750 stack_t ss, oss;
1751 int error;
1752
1753 if (uap->ss != NULL) {
1754 error = copyin(uap->ss, &ss, sizeof(ss));
1755 if (error)
1756 return (error);
1757 }
1758 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
1759 (uap->oss != NULL) ? &oss : NULL);
1760 if (error)
1761 return (error);
1762 if (uap->oss != NULL)
1763 error = copyout(&oss, uap->oss, sizeof(stack_t));
1764 return (error);
1765 }
1766
1767 int
kern_sigaltstack(struct thread * td,stack_t * ss,stack_t * oss)1768 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
1769 {
1770 struct proc *p = td->td_proc;
1771 int oonstack;
1772
1773 oonstack = sigonstack(cpu_getstack(td));
1774
1775 if (oss != NULL) {
1776 *oss = td->td_sigstk;
1777 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
1778 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
1779 }
1780
1781 if (ss != NULL) {
1782 if (oonstack)
1783 return (EPERM);
1784 if ((ss->ss_flags & ~SS_DISABLE) != 0)
1785 return (EINVAL);
1786 if (!(ss->ss_flags & SS_DISABLE)) {
1787 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
1788 return (ENOMEM);
1789
1790 td->td_sigstk = *ss;
1791 td->td_pflags |= TDP_ALTSTACK;
1792 } else {
1793 td->td_pflags &= ~TDP_ALTSTACK;
1794 }
1795 }
1796 return (0);
1797 }
1798
1799 struct killpg1_ctx {
1800 struct thread *td;
1801 ksiginfo_t *ksi;
1802 int sig;
1803 bool sent;
1804 bool found;
1805 int ret;
1806 };
1807
1808 static void
killpg1_sendsig_locked(struct proc * p,struct killpg1_ctx * arg)1809 killpg1_sendsig_locked(struct proc *p, struct killpg1_ctx *arg)
1810 {
1811 int err;
1812
1813 err = p_cansignal(arg->td, p, arg->sig);
1814 if (err == 0 && arg->sig != 0)
1815 pksignal(p, arg->sig, arg->ksi);
1816 if (err != ESRCH)
1817 arg->found = true;
1818 if (err == 0)
1819 arg->sent = true;
1820 else if (arg->ret == 0 && err != ESRCH && err != EPERM)
1821 arg->ret = err;
1822 }
1823
1824 static void
killpg1_sendsig(struct proc * p,bool notself,struct killpg1_ctx * arg)1825 killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg)
1826 {
1827
1828 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 ||
1829 (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW)
1830 return;
1831
1832 PROC_LOCK(p);
1833 killpg1_sendsig_locked(p, arg);
1834 PROC_UNLOCK(p);
1835 }
1836
1837 static void
kill_processes_prison_cb(struct proc * p,void * arg)1838 kill_processes_prison_cb(struct proc *p, void *arg)
1839 {
1840 struct killpg1_ctx *ctx = arg;
1841
1842 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 ||
1843 (p == ctx->td->td_proc) || p->p_state == PRS_NEW)
1844 return;
1845
1846 killpg1_sendsig_locked(p, ctx);
1847 }
1848
1849 /*
1850 * Common code for kill process group/broadcast kill.
1851 * td is the calling thread, as usual.
1852 */
1853 static int
killpg1(struct thread * td,int sig,int pgid,int all,ksiginfo_t * ksi)1854 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
1855 {
1856 struct proc *p;
1857 struct pgrp *pgrp;
1858 struct killpg1_ctx arg;
1859
1860 arg.td = td;
1861 arg.ksi = ksi;
1862 arg.sig = sig;
1863 arg.sent = false;
1864 arg.found = false;
1865 arg.ret = 0;
1866 if (all) {
1867 /*
1868 * broadcast
1869 */
1870 prison_proc_iterate(td->td_ucred->cr_prison,
1871 kill_processes_prison_cb, &arg);
1872 } else {
1873 again:
1874 sx_slock(&proctree_lock);
1875 if (pgid == 0) {
1876 /*
1877 * zero pgid means send to my process group.
1878 */
1879 pgrp = td->td_proc->p_pgrp;
1880 PGRP_LOCK(pgrp);
1881 } else {
1882 pgrp = pgfind(pgid);
1883 if (pgrp == NULL) {
1884 sx_sunlock(&proctree_lock);
1885 return (ESRCH);
1886 }
1887 }
1888 sx_sunlock(&proctree_lock);
1889 if (!sx_try_xlock(&pgrp->pg_killsx)) {
1890 PGRP_UNLOCK(pgrp);
1891 sx_xlock(&pgrp->pg_killsx);
1892 sx_xunlock(&pgrp->pg_killsx);
1893 goto again;
1894 }
1895 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1896 killpg1_sendsig(p, false, &arg);
1897 }
1898 PGRP_UNLOCK(pgrp);
1899 sx_xunlock(&pgrp->pg_killsx);
1900 }
1901 MPASS(arg.ret != 0 || arg.found || !arg.sent);
1902 if (arg.ret == 0 && !arg.sent)
1903 arg.ret = arg.found ? EPERM : ESRCH;
1904 return (arg.ret);
1905 }
1906
1907 #ifndef _SYS_SYSPROTO_H_
1908 struct kill_args {
1909 int pid;
1910 int signum;
1911 };
1912 #endif
1913 /* ARGSUSED */
1914 int
sys_kill(struct thread * td,struct kill_args * uap)1915 sys_kill(struct thread *td, struct kill_args *uap)
1916 {
1917
1918 return (kern_kill(td, uap->pid, uap->signum));
1919 }
1920
1921 int
kern_kill(struct thread * td,pid_t pid,int signum)1922 kern_kill(struct thread *td, pid_t pid, int signum)
1923 {
1924 ksiginfo_t ksi;
1925 struct proc *p;
1926 int error;
1927
1928 /*
1929 * A process in capability mode can send signals only to himself.
1930 * The main rationale behind this is that abort(3) is implemented as
1931 * kill(getpid(), SIGABRT).
1932 */
1933 if (pid != td->td_proc->p_pid) {
1934 if (CAP_TRACING(td))
1935 ktrcapfail(CAPFAIL_SIGNAL, &signum);
1936 if (IN_CAPABILITY_MODE(td))
1937 return (ECAPMODE);
1938 }
1939
1940 AUDIT_ARG_SIGNUM(signum);
1941 AUDIT_ARG_PID(pid);
1942 if ((u_int)signum > _SIG_MAXSIG)
1943 return (EINVAL);
1944
1945 ksiginfo_init(&ksi);
1946 ksi.ksi_signo = signum;
1947 ksi.ksi_code = SI_USER;
1948 ksi.ksi_pid = td->td_proc->p_pid;
1949 ksi.ksi_uid = td->td_ucred->cr_ruid;
1950
1951 if (pid > 0) {
1952 /* kill single process */
1953 if ((p = pfind_any(pid)) == NULL)
1954 return (ESRCH);
1955 AUDIT_ARG_PROCESS(p);
1956 error = p_cansignal(td, p, signum);
1957 if (error == 0 && signum)
1958 pksignal(p, signum, &ksi);
1959 PROC_UNLOCK(p);
1960 return (error);
1961 }
1962 switch (pid) {
1963 case -1: /* broadcast signal */
1964 return (killpg1(td, signum, 0, 1, &ksi));
1965 case 0: /* signal own process group */
1966 return (killpg1(td, signum, 0, 0, &ksi));
1967 default: /* negative explicit process group */
1968 return (killpg1(td, signum, -pid, 0, &ksi));
1969 }
1970 /* NOTREACHED */
1971 }
1972
1973 int
sys_pdkill(struct thread * td,struct pdkill_args * uap)1974 sys_pdkill(struct thread *td, struct pdkill_args *uap)
1975 {
1976 struct proc *p;
1977 int error;
1978
1979 AUDIT_ARG_SIGNUM(uap->signum);
1980 AUDIT_ARG_FD(uap->fd);
1981 if ((u_int)uap->signum > _SIG_MAXSIG)
1982 return (EINVAL);
1983
1984 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p);
1985 if (error)
1986 return (error);
1987 AUDIT_ARG_PROCESS(p);
1988 error = p_cansignal(td, p, uap->signum);
1989 if (error == 0 && uap->signum)
1990 kern_psignal(p, uap->signum);
1991 PROC_UNLOCK(p);
1992 return (error);
1993 }
1994
1995 #if defined(COMPAT_43)
1996 #ifndef _SYS_SYSPROTO_H_
1997 struct okillpg_args {
1998 int pgid;
1999 int signum;
2000 };
2001 #endif
2002 /* ARGSUSED */
2003 int
okillpg(struct thread * td,struct okillpg_args * uap)2004 okillpg(struct thread *td, struct okillpg_args *uap)
2005 {
2006 ksiginfo_t ksi;
2007
2008 AUDIT_ARG_SIGNUM(uap->signum);
2009 AUDIT_ARG_PID(uap->pgid);
2010 if ((u_int)uap->signum > _SIG_MAXSIG)
2011 return (EINVAL);
2012
2013 ksiginfo_init(&ksi);
2014 ksi.ksi_signo = uap->signum;
2015 ksi.ksi_code = SI_USER;
2016 ksi.ksi_pid = td->td_proc->p_pid;
2017 ksi.ksi_uid = td->td_ucred->cr_ruid;
2018 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
2019 }
2020 #endif /* COMPAT_43 */
2021
2022 #ifndef _SYS_SYSPROTO_H_
2023 struct sigqueue_args {
2024 pid_t pid;
2025 int signum;
2026 /* union sigval */ void *value;
2027 };
2028 #endif
2029 int
sys_sigqueue(struct thread * td,struct sigqueue_args * uap)2030 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
2031 {
2032 union sigval sv;
2033
2034 sv.sival_ptr = uap->value;
2035
2036 return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
2037 }
2038
2039 int
kern_sigqueue(struct thread * td,pid_t pid,int signumf,union sigval * value)2040 kern_sigqueue(struct thread *td, pid_t pid, int signumf, union sigval *value)
2041 {
2042 ksiginfo_t ksi;
2043 struct proc *p;
2044 struct thread *td2;
2045 u_int signum;
2046 int error;
2047
2048 signum = signumf & ~__SIGQUEUE_TID;
2049 if (signum > _SIG_MAXSIG)
2050 return (EINVAL);
2051
2052 /*
2053 * Specification says sigqueue can only send signal to
2054 * single process.
2055 */
2056 if (pid <= 0)
2057 return (EINVAL);
2058
2059 if ((signumf & __SIGQUEUE_TID) == 0) {
2060 if ((p = pfind_any(pid)) == NULL)
2061 return (ESRCH);
2062 td2 = NULL;
2063 } else {
2064 p = td->td_proc;
2065 td2 = tdfind((lwpid_t)pid, p->p_pid);
2066 if (td2 == NULL)
2067 return (ESRCH);
2068 }
2069
2070 error = p_cansignal(td, p, signum);
2071 if (error == 0 && signum != 0) {
2072 ksiginfo_init(&ksi);
2073 ksi.ksi_flags = KSI_SIGQ;
2074 ksi.ksi_signo = signum;
2075 ksi.ksi_code = SI_QUEUE;
2076 ksi.ksi_pid = td->td_proc->p_pid;
2077 ksi.ksi_uid = td->td_ucred->cr_ruid;
2078 ksi.ksi_value = *value;
2079 error = tdsendsignal(p, td2, ksi.ksi_signo, &ksi);
2080 }
2081 PROC_UNLOCK(p);
2082 return (error);
2083 }
2084
2085 /*
2086 * Send a signal to a process group. If checktty is 1,
2087 * limit to members which have a controlling terminal.
2088 */
2089 void
pgsignal(struct pgrp * pgrp,int sig,int checkctty,ksiginfo_t * ksi)2090 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
2091 {
2092 struct proc *p;
2093
2094 if (pgrp) {
2095 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
2096 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
2097 PROC_LOCK(p);
2098 if (p->p_state == PRS_NORMAL &&
2099 (checkctty == 0 || p->p_flag & P_CONTROLT))
2100 pksignal(p, sig, ksi);
2101 PROC_UNLOCK(p);
2102 }
2103 }
2104 }
2105
2106 /*
2107 * Recalculate the signal mask and reset the signal disposition after
2108 * usermode frame for delivery is formed. Should be called after
2109 * mach-specific routine, because sysent->sv_sendsig() needs correct
2110 * ps_siginfo and signal mask.
2111 */
2112 static void
postsig_done(int sig,struct thread * td,struct sigacts * ps)2113 postsig_done(int sig, struct thread *td, struct sigacts *ps)
2114 {
2115 sigset_t mask;
2116
2117 mtx_assert(&ps->ps_mtx, MA_OWNED);
2118 td->td_ru.ru_nsignals++;
2119 mask = ps->ps_catchmask[_SIG_IDX(sig)];
2120 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2121 SIGADDSET(mask, sig);
2122 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
2123 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
2124 if (SIGISMEMBER(ps->ps_sigreset, sig))
2125 sigdflt(ps, sig);
2126 }
2127
2128 /*
2129 * Send a signal caused by a trap to the current thread. If it will be
2130 * caught immediately, deliver it with correct code. Otherwise, post it
2131 * normally.
2132 */
2133 void
trapsignal(struct thread * td,ksiginfo_t * ksi)2134 trapsignal(struct thread *td, ksiginfo_t *ksi)
2135 {
2136 struct sigacts *ps;
2137 struct proc *p;
2138 sigset_t sigmask;
2139 int sig;
2140
2141 p = td->td_proc;
2142 sig = ksi->ksi_signo;
2143 KASSERT(_SIG_VALID(sig), ("invalid signal"));
2144
2145 sigfastblock_fetch(td);
2146 PROC_LOCK(p);
2147 ps = p->p_sigacts;
2148 mtx_lock(&ps->ps_mtx);
2149 sigmask = td->td_sigmask;
2150 if (td->td_sigblock_val != 0)
2151 SIGSETOR(sigmask, fastblock_mask);
2152 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
2153 !SIGISMEMBER(sigmask, sig)) {
2154 #ifdef KTRACE
2155 if (KTRPOINT(curthread, KTR_PSIG))
2156 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
2157 &td->td_sigmask, ksi->ksi_code);
2158 #endif
2159 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
2160 ksi, &td->td_sigmask);
2161 postsig_done(sig, td, ps);
2162 mtx_unlock(&ps->ps_mtx);
2163 } else {
2164 /*
2165 * Avoid a possible infinite loop if the thread
2166 * masking the signal or process is ignoring the
2167 * signal.
2168 */
2169 if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) ||
2170 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
2171 SIGDELSET(td->td_sigmask, sig);
2172 SIGDELSET(ps->ps_sigcatch, sig);
2173 SIGDELSET(ps->ps_sigignore, sig);
2174 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2175 td->td_pflags &= ~TDP_SIGFASTBLOCK;
2176 td->td_sigblock_val = 0;
2177 }
2178 mtx_unlock(&ps->ps_mtx);
2179 p->p_sig = sig; /* XXX to verify code */
2180 tdsendsignal(p, td, sig, ksi);
2181 }
2182 PROC_UNLOCK(p);
2183 }
2184
2185 static struct thread *
sigtd(struct proc * p,int sig,bool fast_sigblock)2186 sigtd(struct proc *p, int sig, bool fast_sigblock)
2187 {
2188 struct thread *td, *signal_td;
2189
2190 PROC_LOCK_ASSERT(p, MA_OWNED);
2191 MPASS(!fast_sigblock || p == curproc);
2192
2193 /*
2194 * Check if current thread can handle the signal without
2195 * switching context to another thread.
2196 */
2197 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) &&
2198 (!fast_sigblock || curthread->td_sigblock_val == 0))
2199 return (curthread);
2200
2201 /* Find a non-stopped thread that does not mask the signal. */
2202 signal_td = NULL;
2203 FOREACH_THREAD_IN_PROC(p, td) {
2204 if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock ||
2205 td != curthread || td->td_sigblock_val == 0) &&
2206 (td->td_flags & TDF_BOUNDARY) == 0) {
2207 signal_td = td;
2208 break;
2209 }
2210 }
2211 /* Select random (first) thread if no better match was found. */
2212 if (signal_td == NULL)
2213 signal_td = FIRST_THREAD_IN_PROC(p);
2214 return (signal_td);
2215 }
2216
2217 /*
2218 * Send the signal to the process. If the signal has an action, the action
2219 * is usually performed by the target process rather than the caller; we add
2220 * the signal to the set of pending signals for the process.
2221 *
2222 * Exceptions:
2223 * o When a stop signal is sent to a sleeping process that takes the
2224 * default action, the process is stopped without awakening it.
2225 * o SIGCONT restarts stopped processes (or puts them back to sleep)
2226 * regardless of the signal action (eg, blocked or ignored).
2227 *
2228 * Other ignored signals are discarded immediately.
2229 *
2230 * NB: This function may be entered from the debugger via the "kill" DDB
2231 * command. There is little that can be done to mitigate the possibly messy
2232 * side effects of this unwise possibility.
2233 */
2234 void
kern_psignal(struct proc * p,int sig)2235 kern_psignal(struct proc *p, int sig)
2236 {
2237 ksiginfo_t ksi;
2238
2239 ksiginfo_init(&ksi);
2240 ksi.ksi_signo = sig;
2241 ksi.ksi_code = SI_KERNEL;
2242 (void) tdsendsignal(p, NULL, sig, &ksi);
2243 }
2244
2245 int
pksignal(struct proc * p,int sig,ksiginfo_t * ksi)2246 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
2247 {
2248
2249 return (tdsendsignal(p, NULL, sig, ksi));
2250 }
2251
2252 /* Utility function for finding a thread to send signal event to. */
2253 int
sigev_findtd(struct proc * p,struct sigevent * sigev,struct thread ** ttd)2254 sigev_findtd(struct proc *p, struct sigevent *sigev, struct thread **ttd)
2255 {
2256 struct thread *td;
2257
2258 if (sigev->sigev_notify == SIGEV_THREAD_ID) {
2259 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
2260 if (td == NULL)
2261 return (ESRCH);
2262 *ttd = td;
2263 } else {
2264 *ttd = NULL;
2265 PROC_LOCK(p);
2266 }
2267 return (0);
2268 }
2269
2270 void
tdsignal(struct thread * td,int sig)2271 tdsignal(struct thread *td, int sig)
2272 {
2273 ksiginfo_t ksi;
2274
2275 ksiginfo_init(&ksi);
2276 ksi.ksi_signo = sig;
2277 ksi.ksi_code = SI_KERNEL;
2278 (void) tdsendsignal(td->td_proc, td, sig, &ksi);
2279 }
2280
2281 void
tdksignal(struct thread * td,int sig,ksiginfo_t * ksi)2282 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
2283 {
2284
2285 (void) tdsendsignal(td->td_proc, td, sig, ksi);
2286 }
2287
2288 static void
sig_sleepq_abort(struct thread * td,int intrval)2289 sig_sleepq_abort(struct thread *td, int intrval)
2290 {
2291 THREAD_LOCK_ASSERT(td, MA_OWNED);
2292
2293 if (intrval == 0 && (td->td_flags & TDF_SIGWAIT) == 0)
2294 thread_unlock(td);
2295 else
2296 sleepq_abort(td, intrval);
2297 }
2298
2299 int
tdsendsignal(struct proc * p,struct thread * td,int sig,ksiginfo_t * ksi)2300 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
2301 {
2302 sig_t action;
2303 sigqueue_t *sigqueue;
2304 struct sigacts *ps;
2305 int intrval, prop, ret;
2306
2307 MPASS(td == NULL || p == td->td_proc);
2308 PROC_LOCK_ASSERT(p, MA_OWNED);
2309
2310 if (!_SIG_VALID(sig))
2311 panic("%s(): invalid signal %d", __func__, sig);
2312
2313 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
2314
2315 /*
2316 * IEEE Std 1003.1-2001: return success when killing a zombie.
2317 */
2318 if (p->p_state == PRS_ZOMBIE) {
2319 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2320 ksiginfo_tryfree(ksi);
2321 return (0);
2322 }
2323
2324 ps = p->p_sigacts;
2325 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
2326 prop = sigprop(sig);
2327
2328 if (td == NULL) {
2329 td = sigtd(p, sig, false);
2330 sigqueue = &p->p_sigqueue;
2331 } else
2332 sigqueue = &td->td_sigqueue;
2333
2334 SDT_PROBE3(proc, , , signal__send, td, p, sig);
2335
2336 /*
2337 * If the signal is being ignored, then we forget about it
2338 * immediately, except when the target process executes
2339 * sigwait(). (Note: we don't set SIGCONT in ps_sigignore,
2340 * and if it is set to SIG_IGN, action will be SIG_DFL here.)
2341 */
2342 mtx_lock(&ps->ps_mtx);
2343 if (SIGISMEMBER(ps->ps_sigignore, sig)) {
2344 if (kern_sig_discard_ign &&
2345 (p->p_sysent->sv_flags & SV_SIG_DISCIGN) == 0) {
2346 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
2347
2348 mtx_unlock(&ps->ps_mtx);
2349 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2350 ksiginfo_tryfree(ksi);
2351 return (0);
2352 } else {
2353 action = SIG_CATCH;
2354 intrval = 0;
2355 }
2356 } else {
2357 if (SIGISMEMBER(td->td_sigmask, sig))
2358 action = SIG_HOLD;
2359 else if (SIGISMEMBER(ps->ps_sigcatch, sig))
2360 action = SIG_CATCH;
2361 else
2362 action = SIG_DFL;
2363 if (SIGISMEMBER(ps->ps_sigintr, sig))
2364 intrval = EINTR;
2365 else
2366 intrval = ERESTART;
2367 }
2368 mtx_unlock(&ps->ps_mtx);
2369
2370 if (prop & SIGPROP_CONT)
2371 sigqueue_delete_stopmask_proc(p);
2372 else if (prop & SIGPROP_STOP) {
2373 if (pt_attach_transparent &&
2374 (p->p_flag & P_TRACED) != 0 &&
2375 (p->p_flag2 & P2_PTRACE_FSTP) != 0) {
2376 td->td_dbgflags |= TDB_FSTP;
2377 PROC_SLOCK(p);
2378 sig_handle_first_stop(td, p, sig, true);
2379 PROC_SUNLOCK(p);
2380 return (0);
2381 }
2382
2383 /*
2384 * If sending a tty stop signal to a member of an orphaned
2385 * process group, discard the signal here if the action
2386 * is default; don't stop the process below if sleeping,
2387 * and don't clear any pending SIGCONT.
2388 */
2389 if ((prop & SIGPROP_TTYSTOP) != 0 &&
2390 (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 &&
2391 action == SIG_DFL) {
2392 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2393 ksiginfo_tryfree(ksi);
2394 return (0);
2395 }
2396 sigqueue_delete_proc(p, SIGCONT);
2397 if (p->p_flag & P_CONTINUED) {
2398 p->p_flag &= ~P_CONTINUED;
2399 PROC_LOCK(p->p_pptr);
2400 sigqueue_take(p->p_ksi);
2401 PROC_UNLOCK(p->p_pptr);
2402 }
2403 }
2404
2405 ret = sigqueue_add(sigqueue, sig, ksi);
2406 if (ret != 0)
2407 return (ret);
2408 signotify(td);
2409 /*
2410 * Defer further processing for signals which are held,
2411 * except that stopped processes must be continued by SIGCONT.
2412 */
2413 if (action == SIG_HOLD &&
2414 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG)))
2415 return (0);
2416
2417 /*
2418 * Some signals have a process-wide effect and a per-thread
2419 * component. Most processing occurs when the process next
2420 * tries to cross the user boundary, however there are some
2421 * times when processing needs to be done immediately, such as
2422 * waking up threads so that they can cross the user boundary.
2423 * We try to do the per-process part here.
2424 */
2425 if (P_SHOULDSTOP(p)) {
2426 KASSERT(!(p->p_flag & P_WEXIT),
2427 ("signal to stopped but exiting process"));
2428 if (sig == SIGKILL) {
2429 /*
2430 * If traced process is already stopped,
2431 * then no further action is necessary.
2432 */
2433 if (p->p_flag & P_TRACED)
2434 return (0);
2435 /*
2436 * SIGKILL sets process running.
2437 * It will die elsewhere.
2438 * All threads must be restarted.
2439 */
2440 p->p_flag &= ~P_STOPPED_SIG;
2441 goto runfast;
2442 }
2443
2444 if (prop & SIGPROP_CONT) {
2445 /*
2446 * If traced process is already stopped,
2447 * then no further action is necessary.
2448 */
2449 if (p->p_flag & P_TRACED)
2450 return (0);
2451 /*
2452 * If SIGCONT is default (or ignored), we continue the
2453 * process but don't leave the signal in sigqueue as
2454 * it has no further action. If SIGCONT is held, we
2455 * continue the process and leave the signal in
2456 * sigqueue. If the process catches SIGCONT, let it
2457 * handle the signal itself. If it isn't waiting on
2458 * an event, it goes back to run state.
2459 * Otherwise, process goes back to sleep state.
2460 */
2461 p->p_flag &= ~P_STOPPED_SIG;
2462 PROC_SLOCK(p);
2463 if (p->p_numthreads == p->p_suspcount) {
2464 PROC_SUNLOCK(p);
2465 p->p_flag |= P_CONTINUED;
2466 p->p_xsig = SIGCONT;
2467 PROC_LOCK(p->p_pptr);
2468 childproc_continued(p);
2469 PROC_UNLOCK(p->p_pptr);
2470 PROC_SLOCK(p);
2471 }
2472 if (action == SIG_DFL) {
2473 thread_unsuspend(p);
2474 PROC_SUNLOCK(p);
2475 sigqueue_delete(sigqueue, sig);
2476 goto out_cont;
2477 }
2478 if (action == SIG_CATCH) {
2479 /*
2480 * The process wants to catch it so it needs
2481 * to run at least one thread, but which one?
2482 */
2483 PROC_SUNLOCK(p);
2484 goto runfast;
2485 }
2486 /*
2487 * The signal is not ignored or caught.
2488 */
2489 thread_unsuspend(p);
2490 PROC_SUNLOCK(p);
2491 goto out_cont;
2492 }
2493
2494 if (prop & SIGPROP_STOP) {
2495 /*
2496 * If traced process is already stopped,
2497 * then no further action is necessary.
2498 */
2499 if (p->p_flag & P_TRACED)
2500 return (0);
2501 /*
2502 * Already stopped, don't need to stop again
2503 * (If we did the shell could get confused).
2504 * Just make sure the signal STOP bit set.
2505 */
2506 p->p_flag |= P_STOPPED_SIG;
2507 sigqueue_delete(sigqueue, sig);
2508 return (0);
2509 }
2510
2511 /*
2512 * All other kinds of signals:
2513 * If a thread is sleeping interruptibly, simulate a
2514 * wakeup so that when it is continued it will be made
2515 * runnable and can look at the signal. However, don't make
2516 * the PROCESS runnable, leave it stopped.
2517 * It may run a bit until it hits a thread_suspend_check().
2518 */
2519 PROC_SLOCK(p);
2520 thread_lock(td);
2521 if (TD_CAN_ABORT(td))
2522 sig_sleepq_abort(td, intrval);
2523 else
2524 thread_unlock(td);
2525 PROC_SUNLOCK(p);
2526 return (0);
2527 /*
2528 * Mutexes are short lived. Threads waiting on them will
2529 * hit thread_suspend_check() soon.
2530 */
2531 } else if (p->p_state == PRS_NORMAL) {
2532 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2533 tdsigwakeup(td, sig, action, intrval);
2534 return (0);
2535 }
2536
2537 MPASS(action == SIG_DFL);
2538
2539 if (prop & SIGPROP_STOP) {
2540 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2541 return (0);
2542 p->p_flag |= P_STOPPED_SIG;
2543 p->p_xsig = sig;
2544 PROC_SLOCK(p);
2545 sig_suspend_threads(td, p);
2546 if (p->p_numthreads == p->p_suspcount) {
2547 /*
2548 * only thread sending signal to another
2549 * process can reach here, if thread is sending
2550 * signal to its process, because thread does
2551 * not suspend itself here, p_numthreads
2552 * should never be equal to p_suspcount.
2553 */
2554 thread_stopped(p);
2555 PROC_SUNLOCK(p);
2556 sigqueue_delete_proc(p, p->p_xsig);
2557 } else
2558 PROC_SUNLOCK(p);
2559 return (0);
2560 }
2561 } else {
2562 /* Not in "NORMAL" state. discard the signal. */
2563 sigqueue_delete(sigqueue, sig);
2564 return (0);
2565 }
2566
2567 /*
2568 * The process is not stopped so we need to apply the signal to all the
2569 * running threads.
2570 */
2571 runfast:
2572 tdsigwakeup(td, sig, action, intrval);
2573 PROC_SLOCK(p);
2574 thread_unsuspend(p);
2575 PROC_SUNLOCK(p);
2576 out_cont:
2577 itimer_proc_continue(p);
2578 kqtimer_proc_continue(p);
2579
2580 return (0);
2581 }
2582
2583 /*
2584 * The force of a signal has been directed against a single
2585 * thread. We need to see what we can do about knocking it
2586 * out of any sleep it may be in etc.
2587 */
2588 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2589 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2590 {
2591 struct proc *p = td->td_proc;
2592 int prop;
2593
2594 PROC_LOCK_ASSERT(p, MA_OWNED);
2595 prop = sigprop(sig);
2596
2597 PROC_SLOCK(p);
2598 thread_lock(td);
2599 /*
2600 * Bring the priority of a thread up if we want it to get
2601 * killed in this lifetime. Be careful to avoid bumping the
2602 * priority of the idle thread, since we still allow to signal
2603 * kernel processes.
2604 */
2605 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 &&
2606 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2607 sched_prio(td, PUSER);
2608 if (TD_ON_SLEEPQ(td)) {
2609 /*
2610 * If thread is sleeping uninterruptibly
2611 * we can't interrupt the sleep... the signal will
2612 * be noticed when the process returns through
2613 * trap() or syscall().
2614 */
2615 if ((td->td_flags & TDF_SINTR) == 0)
2616 goto out;
2617 /*
2618 * If SIGCONT is default (or ignored) and process is
2619 * asleep, we are finished; the process should not
2620 * be awakened.
2621 */
2622 if ((prop & SIGPROP_CONT) && action == SIG_DFL) {
2623 thread_unlock(td);
2624 PROC_SUNLOCK(p);
2625 sigqueue_delete(&p->p_sigqueue, sig);
2626 /*
2627 * It may be on either list in this state.
2628 * Remove from both for now.
2629 */
2630 sigqueue_delete(&td->td_sigqueue, sig);
2631 return;
2632 }
2633
2634 /*
2635 * Don't awaken a sleeping thread for SIGSTOP if the
2636 * STOP signal is deferred.
2637 */
2638 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2639 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2640 goto out;
2641
2642 /*
2643 * Give low priority threads a better chance to run.
2644 */
2645 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2646 sched_prio(td, PUSER);
2647
2648 sig_sleepq_abort(td, intrval);
2649 PROC_SUNLOCK(p);
2650 return;
2651 }
2652
2653 /*
2654 * Other states do nothing with the signal immediately,
2655 * other than kicking ourselves if we are running.
2656 * It will either never be noticed, or noticed very soon.
2657 */
2658 #ifdef SMP
2659 if (TD_IS_RUNNING(td) && td != curthread)
2660 forward_signal(td);
2661 #endif
2662
2663 out:
2664 PROC_SUNLOCK(p);
2665 thread_unlock(td);
2666 }
2667
2668 static void
ptrace_coredumpreq(struct thread * td,struct proc * p,struct thr_coredump_req * tcq)2669 ptrace_coredumpreq(struct thread *td, struct proc *p,
2670 struct thr_coredump_req *tcq)
2671 {
2672 void *rl_cookie;
2673
2674 if (p->p_sysent->sv_coredump == NULL) {
2675 tcq->tc_error = ENOSYS;
2676 return;
2677 }
2678
2679 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX);
2680 tcq->tc_error = p->p_sysent->sv_coredump(td, tcq->tc_vp,
2681 tcq->tc_limit, tcq->tc_flags);
2682 vn_rangelock_unlock(tcq->tc_vp, rl_cookie);
2683 }
2684
2685 static void
ptrace_syscallreq(struct thread * td,struct proc * p,struct thr_syscall_req * tsr)2686 ptrace_syscallreq(struct thread *td, struct proc *p,
2687 struct thr_syscall_req *tsr)
2688 {
2689 struct sysentvec *sv;
2690 struct sysent *se;
2691 register_t rv_saved[2];
2692 int error, nerror;
2693 int sc;
2694 bool audited, sy_thr_static;
2695
2696 sv = p->p_sysent;
2697 if (sv->sv_table == NULL || sv->sv_size < tsr->ts_sa.code) {
2698 tsr->ts_ret.sr_error = ENOSYS;
2699 return;
2700 }
2701
2702 sc = tsr->ts_sa.code;
2703 if (sc == SYS_syscall || sc == SYS___syscall) {
2704 sc = tsr->ts_sa.args[0];
2705 memmove(&tsr->ts_sa.args[0], &tsr->ts_sa.args[1],
2706 sizeof(register_t) * (tsr->ts_nargs - 1));
2707 }
2708
2709 tsr->ts_sa.callp = se = &sv->sv_table[sc];
2710
2711 VM_CNT_INC(v_syscall);
2712 td->td_pticks = 0;
2713 if (__predict_false(td->td_cowgen != atomic_load_int(
2714 &td->td_proc->p_cowgen)))
2715 thread_cow_update(td);
2716
2717 td->td_sa = tsr->ts_sa;
2718
2719 #ifdef CAPABILITY_MODE
2720 if ((se->sy_flags & SYF_CAPENABLED) == 0) {
2721 if (CAP_TRACING(td))
2722 ktrcapfail(CAPFAIL_SYSCALL, NULL);
2723 if (IN_CAPABILITY_MODE(td)) {
2724 tsr->ts_ret.sr_error = ECAPMODE;
2725 return;
2726 }
2727 }
2728 #endif
2729
2730 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2731 audited = AUDIT_SYSCALL_ENTER(sc, td) != 0;
2732
2733 if (!sy_thr_static) {
2734 error = syscall_thread_enter(td, &se);
2735 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2736 if (error != 0) {
2737 tsr->ts_ret.sr_error = error;
2738 return;
2739 }
2740 }
2741
2742 rv_saved[0] = td->td_retval[0];
2743 rv_saved[1] = td->td_retval[1];
2744 nerror = td->td_errno;
2745 td->td_retval[0] = 0;
2746 td->td_retval[1] = 0;
2747
2748 #ifdef KDTRACE_HOOKS
2749 if (se->sy_entry != 0)
2750 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_ENTRY, 0);
2751 #endif
2752 tsr->ts_ret.sr_error = se->sy_call(td, tsr->ts_sa.args);
2753 #ifdef KDTRACE_HOOKS
2754 if (se->sy_return != 0)
2755 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_RETURN,
2756 tsr->ts_ret.sr_error != 0 ? -1 : td->td_retval[0]);
2757 #endif
2758
2759 tsr->ts_ret.sr_retval[0] = td->td_retval[0];
2760 tsr->ts_ret.sr_retval[1] = td->td_retval[1];
2761 td->td_retval[0] = rv_saved[0];
2762 td->td_retval[1] = rv_saved[1];
2763 td->td_errno = nerror;
2764
2765 if (audited)
2766 AUDIT_SYSCALL_EXIT(error, td);
2767 if (!sy_thr_static)
2768 syscall_thread_exit(td, se);
2769 }
2770
2771 static void
ptrace_remotereq(struct thread * td,int flag)2772 ptrace_remotereq(struct thread *td, int flag)
2773 {
2774 struct proc *p;
2775
2776 MPASS(td == curthread);
2777 p = td->td_proc;
2778 PROC_LOCK_ASSERT(p, MA_OWNED);
2779 if ((td->td_dbgflags & flag) == 0)
2780 return;
2781 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped"));
2782 KASSERT(td->td_remotereq != NULL, ("td_remotereq is NULL"));
2783
2784 PROC_UNLOCK(p);
2785 switch (flag) {
2786 case TDB_COREDUMPREQ:
2787 ptrace_coredumpreq(td, p, td->td_remotereq);
2788 break;
2789 case TDB_SCREMOTEREQ:
2790 ptrace_syscallreq(td, p, td->td_remotereq);
2791 break;
2792 default:
2793 __unreachable();
2794 }
2795 PROC_LOCK(p);
2796
2797 MPASS((td->td_dbgflags & flag) != 0);
2798 td->td_dbgflags &= ~flag;
2799 td->td_remotereq = NULL;
2800 wakeup(p);
2801 }
2802
2803 static void
sig_suspend_threads(struct thread * td,struct proc * p)2804 sig_suspend_threads(struct thread *td, struct proc *p)
2805 {
2806 struct thread *td2;
2807
2808 PROC_LOCK_ASSERT(p, MA_OWNED);
2809 PROC_SLOCK_ASSERT(p, MA_OWNED);
2810
2811 FOREACH_THREAD_IN_PROC(p, td2) {
2812 thread_lock(td2);
2813 ast_sched_locked(td2, TDA_SUSPEND);
2814 if (TD_IS_SLEEPING(td2) && (td2->td_flags & TDF_SINTR) != 0) {
2815 if (td2->td_flags & TDF_SBDRY) {
2816 /*
2817 * Once a thread is asleep with
2818 * TDF_SBDRY and without TDF_SERESTART
2819 * or TDF_SEINTR set, it should never
2820 * become suspended due to this check.
2821 */
2822 KASSERT(!TD_IS_SUSPENDED(td2),
2823 ("thread with deferred stops suspended"));
2824 if (TD_SBDRY_INTR(td2)) {
2825 sleepq_abort(td2, TD_SBDRY_ERRNO(td2));
2826 continue;
2827 }
2828 } else if (!TD_IS_SUSPENDED(td2))
2829 thread_suspend_one(td2);
2830 } else if (!TD_IS_SUSPENDED(td2)) {
2831 #ifdef SMP
2832 if (TD_IS_RUNNING(td2) && td2 != td)
2833 forward_signal(td2);
2834 #endif
2835 }
2836 thread_unlock(td2);
2837 }
2838 }
2839
2840 static void
sig_handle_first_stop(struct thread * td,struct proc * p,int sig,bool ext)2841 sig_handle_first_stop(struct thread *td, struct proc *p, int sig, bool ext)
2842 {
2843 if ((td->td_dbgflags & TDB_FSTP) == 0 &&
2844 ((p->p_flag2 & P2_PTRACE_FSTP) != 0 ||
2845 p->p_xthread != NULL))
2846 return;
2847
2848 p->p_xsig = sig;
2849 p->p_xthread = td;
2850
2851 /*
2852 * If we are on sleepqueue already, let sleepqueue
2853 * code decide if it needs to go sleep after attach.
2854 */
2855 if (ext || td->td_wchan == NULL)
2856 td->td_dbgflags &= ~TDB_FSTP;
2857
2858 p->p_flag2 &= ~P2_PTRACE_FSTP;
2859 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2860 sig_suspend_threads(td, 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, false);
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 * Force the current process to exit with the specified signal, dumping core
3630 * if appropriate. We bypass the normal tests for masked and caught signals,
3631 * allowing unrecoverable failures to terminate the process without changing
3632 * signal state. Mark the accounting record with the signal termination.
3633 * If dumping core, save the signal number for the debugger. Calls exit and
3634 * does not return.
3635 */
3636 void
sigexit(struct thread * td,int sig)3637 sigexit(struct thread *td, int sig)
3638 {
3639 struct proc *p = td->td_proc;
3640 const char *coreinfo;
3641 int rv;
3642 bool logexit;
3643
3644 PROC_LOCK_ASSERT(p, MA_OWNED);
3645 proc_set_p2_wexit(p);
3646
3647 p->p_acflag |= AXSIG;
3648 if ((p->p_flag2 & P2_LOGSIGEXIT_CTL) == 0)
3649 logexit = kern_logsigexit != 0;
3650 else
3651 logexit = (p->p_flag2 & P2_LOGSIGEXIT_ENABLE) != 0;
3652
3653 /*
3654 * We must be single-threading to generate a core dump. This
3655 * ensures that the registers in the core file are up-to-date.
3656 * Also, the ELF dump handler assumes that the thread list doesn't
3657 * change out from under it.
3658 *
3659 * XXX If another thread attempts to single-thread before us
3660 * (e.g. via fork()), we won't get a dump at all.
3661 */
3662 if ((sigprop(sig) & SIGPROP_CORE) &&
3663 thread_single(p, SINGLE_NO_EXIT) == 0) {
3664 p->p_sig = sig;
3665 /*
3666 * Log signals which would cause core dumps
3667 * (Log as LOG_INFO to appease those who don't want
3668 * these messages.)
3669 * XXX : Todo, as well as euid, write out ruid too
3670 * Note that coredump() drops proc lock.
3671 */
3672 rv = coredump(td);
3673 switch (rv) {
3674 case 0:
3675 sig |= WCOREFLAG;
3676 coreinfo = " (core dumped)";
3677 break;
3678 case EFAULT:
3679 coreinfo = " (no core dump - bad address)";
3680 break;
3681 case EINVAL:
3682 coreinfo = " (no core dump - invalid argument)";
3683 break;
3684 case EFBIG:
3685 coreinfo = " (no core dump - too large)";
3686 break;
3687 default:
3688 coreinfo = " (no core dump - other error)";
3689 break;
3690 }
3691 if (logexit)
3692 log(LOG_INFO,
3693 "pid %d (%s), jid %d, uid %d: exited on "
3694 "signal %d%s\n", p->p_pid, p->p_comm,
3695 p->p_ucred->cr_prison->pr_id,
3696 td->td_ucred->cr_uid,
3697 sig &~ WCOREFLAG, coreinfo);
3698 } else
3699 PROC_UNLOCK(p);
3700 exit1(td, 0, sig);
3701 /* NOTREACHED */
3702 }
3703
3704 /*
3705 * Send queued SIGCHLD to parent when child process's state
3706 * is changed.
3707 */
3708 static void
sigparent(struct proc * p,int reason,int status)3709 sigparent(struct proc *p, int reason, int status)
3710 {
3711 PROC_LOCK_ASSERT(p, MA_OWNED);
3712 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3713
3714 if (p->p_ksi != NULL) {
3715 p->p_ksi->ksi_signo = SIGCHLD;
3716 p->p_ksi->ksi_code = reason;
3717 p->p_ksi->ksi_status = status;
3718 p->p_ksi->ksi_pid = p->p_pid;
3719 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3720 if (KSI_ONQ(p->p_ksi))
3721 return;
3722 }
3723 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3724 }
3725
3726 static void
childproc_jobstate(struct proc * p,int reason,int sig)3727 childproc_jobstate(struct proc *p, int reason, int sig)
3728 {
3729 struct sigacts *ps;
3730
3731 PROC_LOCK_ASSERT(p, MA_OWNED);
3732 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3733
3734 /*
3735 * Wake up parent sleeping in kern_wait(), also send
3736 * SIGCHLD to parent, but SIGCHLD does not guarantee
3737 * that parent will awake, because parent may masked
3738 * the signal.
3739 */
3740 p->p_pptr->p_flag |= P_STATCHILD;
3741 wakeup(p->p_pptr);
3742
3743 ps = p->p_pptr->p_sigacts;
3744 mtx_lock(&ps->ps_mtx);
3745 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3746 mtx_unlock(&ps->ps_mtx);
3747 sigparent(p, reason, sig);
3748 } else
3749 mtx_unlock(&ps->ps_mtx);
3750 }
3751
3752 void
childproc_stopped(struct proc * p,int reason)3753 childproc_stopped(struct proc *p, int reason)
3754 {
3755
3756 childproc_jobstate(p, reason, p->p_xsig);
3757 }
3758
3759 void
childproc_continued(struct proc * p)3760 childproc_continued(struct proc *p)
3761 {
3762 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3763 }
3764
3765 void
childproc_exited(struct proc * p)3766 childproc_exited(struct proc *p)
3767 {
3768 int reason, status;
3769
3770 if (WCOREDUMP(p->p_xsig)) {
3771 reason = CLD_DUMPED;
3772 status = WTERMSIG(p->p_xsig);
3773 } else if (WIFSIGNALED(p->p_xsig)) {
3774 reason = CLD_KILLED;
3775 status = WTERMSIG(p->p_xsig);
3776 } else {
3777 reason = CLD_EXITED;
3778 status = p->p_xexit;
3779 }
3780 /*
3781 * XXX avoid calling wakeup(p->p_pptr), the work is
3782 * done in exit1().
3783 */
3784 sigparent(p, reason, status);
3785 }
3786
3787 #define MAX_NUM_CORE_FILES 100000
3788 #ifndef NUM_CORE_FILES
3789 #define NUM_CORE_FILES 5
3790 #endif
3791 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES);
3792 static int num_cores = NUM_CORE_FILES;
3793
3794 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3795 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3796 {
3797 int error;
3798 int new_val;
3799
3800 new_val = num_cores;
3801 error = sysctl_handle_int(oidp, &new_val, 0, req);
3802 if (error != 0 || req->newptr == NULL)
3803 return (error);
3804 if (new_val > MAX_NUM_CORE_FILES)
3805 new_val = MAX_NUM_CORE_FILES;
3806 if (new_val < 0)
3807 new_val = 0;
3808 num_cores = new_val;
3809 return (0);
3810 }
3811 SYSCTL_PROC(_debug, OID_AUTO, ncores,
3812 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int),
3813 sysctl_debug_num_cores_check, "I",
3814 "Maximum number of generated process corefiles while using index format");
3815
3816 #define GZIP_SUFFIX ".gz"
3817 #define ZSTD_SUFFIX ".zst"
3818
3819 int compress_user_cores = 0;
3820
3821 static int
sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)3822 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)
3823 {
3824 int error, val;
3825
3826 val = compress_user_cores;
3827 error = sysctl_handle_int(oidp, &val, 0, req);
3828 if (error != 0 || req->newptr == NULL)
3829 return (error);
3830 if (val != 0 && !compressor_avail(val))
3831 return (EINVAL);
3832 compress_user_cores = val;
3833 return (error);
3834 }
3835 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores,
3836 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int),
3837 sysctl_compress_user_cores, "I",
3838 "Enable compression of user corefiles ("
3839 __XSTRING(COMPRESS_GZIP) " = gzip, "
3840 __XSTRING(COMPRESS_ZSTD) " = zstd)");
3841
3842 int compress_user_cores_level = 6;
3843 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN,
3844 &compress_user_cores_level, 0,
3845 "Corefile compression level");
3846
3847 /*
3848 * Protect the access to corefilename[] by allproc_lock.
3849 */
3850 #define corefilename_lock allproc_lock
3851
3852 static char corefilename[MAXPATHLEN] = {"%N.core"};
3853 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3854
3855 static int
sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)3856 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
3857 {
3858 int error;
3859
3860 sx_xlock(&corefilename_lock);
3861 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
3862 req);
3863 sx_xunlock(&corefilename_lock);
3864
3865 return (error);
3866 }
3867 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
3868 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
3869 "Process corefile name format string");
3870
3871 static void
vnode_close_locked(struct thread * td,struct vnode * vp)3872 vnode_close_locked(struct thread *td, struct vnode *vp)
3873 {
3874
3875 VOP_UNLOCK(vp);
3876 vn_close(vp, FWRITE, td->td_ucred, td);
3877 }
3878
3879 /*
3880 * If the core format has a %I in it, then we need to check
3881 * for existing corefiles before defining a name.
3882 * To do this we iterate over 0..ncores to find a
3883 * non-existing core file name to use. If all core files are
3884 * already used we choose the oldest one.
3885 */
3886 static int
corefile_open_last(struct thread * td,char * name,int indexpos,int indexlen,int ncores,struct vnode ** vpp)3887 corefile_open_last(struct thread *td, char *name, int indexpos,
3888 int indexlen, int ncores, struct vnode **vpp)
3889 {
3890 struct vnode *oldvp, *nextvp, *vp;
3891 struct vattr vattr;
3892 struct nameidata nd;
3893 int error, i, flags, oflags, cmode;
3894 char ch;
3895 struct timespec lasttime;
3896
3897 nextvp = oldvp = NULL;
3898 cmode = S_IRUSR | S_IWUSR;
3899 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3900 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3901
3902 for (i = 0; i < ncores; i++) {
3903 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3904
3905 ch = name[indexpos + indexlen];
3906 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen,
3907 i);
3908 name[indexpos + indexlen] = ch;
3909
3910 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name);
3911 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3912 NULL);
3913 if (error != 0)
3914 break;
3915
3916 vp = nd.ni_vp;
3917 NDFREE_PNBUF(&nd);
3918 if ((flags & O_CREAT) == O_CREAT) {
3919 nextvp = vp;
3920 break;
3921 }
3922
3923 error = VOP_GETATTR(vp, &vattr, td->td_ucred);
3924 if (error != 0) {
3925 vnode_close_locked(td, vp);
3926 break;
3927 }
3928
3929 if (oldvp == NULL ||
3930 lasttime.tv_sec > vattr.va_mtime.tv_sec ||
3931 (lasttime.tv_sec == vattr.va_mtime.tv_sec &&
3932 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) {
3933 if (oldvp != NULL)
3934 vn_close(oldvp, FWRITE, td->td_ucred, td);
3935 oldvp = vp;
3936 VOP_UNLOCK(oldvp);
3937 lasttime = vattr.va_mtime;
3938 } else {
3939 vnode_close_locked(td, vp);
3940 }
3941 }
3942
3943 if (oldvp != NULL) {
3944 if (nextvp == NULL) {
3945 if ((td->td_proc->p_flag & P_SUGID) != 0) {
3946 error = EFAULT;
3947 vn_close(oldvp, FWRITE, td->td_ucred, td);
3948 } else {
3949 nextvp = oldvp;
3950 error = vn_lock(nextvp, LK_EXCLUSIVE);
3951 if (error != 0) {
3952 vn_close(nextvp, FWRITE, td->td_ucred,
3953 td);
3954 nextvp = NULL;
3955 }
3956 }
3957 } else {
3958 vn_close(oldvp, FWRITE, td->td_ucred, td);
3959 }
3960 }
3961 if (error != 0) {
3962 if (nextvp != NULL)
3963 vnode_close_locked(td, oldvp);
3964 } else {
3965 *vpp = nextvp;
3966 }
3967
3968 return (error);
3969 }
3970
3971 /*
3972 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3973 * Expand the name described in corefilename, using name, uid, and pid
3974 * and open/create core file.
3975 * corefilename is a printf-like string, with three format specifiers:
3976 * %N name of process ("name")
3977 * %P process id (pid)
3978 * %U user id (uid)
3979 * For example, "%N.core" is the default; they can be disabled completely
3980 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
3981 * This is controlled by the sysctl variable kern.corefile (see above).
3982 */
3983 static int
corefile_open(const char * comm,uid_t uid,pid_t pid,struct thread * td,int compress,int signum,struct vnode ** vpp,char ** namep)3984 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
3985 int compress, int signum, struct vnode **vpp, char **namep)
3986 {
3987 struct sbuf sb;
3988 struct nameidata nd;
3989 const char *format;
3990 char *hostname, *name;
3991 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores;
3992
3993 hostname = NULL;
3994 format = corefilename;
3995 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
3996 indexlen = 0;
3997 indexpos = -1;
3998 ncores = num_cores;
3999 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
4000 sx_slock(&corefilename_lock);
4001 for (i = 0; format[i] != '\0'; i++) {
4002 switch (format[i]) {
4003 case '%': /* Format character */
4004 i++;
4005 switch (format[i]) {
4006 case '%':
4007 sbuf_putc(&sb, '%');
4008 break;
4009 case 'H': /* hostname */
4010 if (hostname == NULL) {
4011 hostname = malloc(MAXHOSTNAMELEN,
4012 M_TEMP, M_WAITOK);
4013 }
4014 getcredhostname(td->td_ucred, hostname,
4015 MAXHOSTNAMELEN);
4016 sbuf_cat(&sb, hostname);
4017 break;
4018 case 'I': /* autoincrementing index */
4019 if (indexpos != -1) {
4020 sbuf_printf(&sb, "%%I");
4021 break;
4022 }
4023
4024 indexpos = sbuf_len(&sb);
4025 sbuf_printf(&sb, "%u", ncores - 1);
4026 indexlen = sbuf_len(&sb) - indexpos;
4027 break;
4028 case 'N': /* process name */
4029 sbuf_printf(&sb, "%s", comm);
4030 break;
4031 case 'P': /* process id */
4032 sbuf_printf(&sb, "%u", pid);
4033 break;
4034 case 'S': /* signal number */
4035 sbuf_printf(&sb, "%i", signum);
4036 break;
4037 case 'U': /* user id */
4038 sbuf_printf(&sb, "%u", uid);
4039 break;
4040 default:
4041 log(LOG_ERR,
4042 "Unknown format character %c in "
4043 "corename `%s'\n", format[i], format);
4044 break;
4045 }
4046 break;
4047 default:
4048 sbuf_putc(&sb, format[i]);
4049 break;
4050 }
4051 }
4052 sx_sunlock(&corefilename_lock);
4053 free(hostname, M_TEMP);
4054 if (compress == COMPRESS_GZIP)
4055 sbuf_cat(&sb, GZIP_SUFFIX);
4056 else if (compress == COMPRESS_ZSTD)
4057 sbuf_cat(&sb, ZSTD_SUFFIX);
4058 if (sbuf_error(&sb) != 0) {
4059 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
4060 "long\n", (long)pid, comm, (u_long)uid);
4061 sbuf_delete(&sb);
4062 free(name, M_TEMP);
4063 return (ENOMEM);
4064 }
4065 sbuf_finish(&sb);
4066 sbuf_delete(&sb);
4067
4068 if (indexpos != -1) {
4069 error = corefile_open_last(td, name, indexpos, indexlen, ncores,
4070 vpp);
4071 if (error != 0) {
4072 log(LOG_ERR,
4073 "pid %d (%s), uid (%u): Path `%s' failed "
4074 "on initial open test, error = %d\n",
4075 pid, comm, uid, name, error);
4076 }
4077 } else {
4078 cmode = S_IRUSR | S_IWUSR;
4079 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
4080 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
4081 flags = O_CREAT | FWRITE | O_NOFOLLOW;
4082 if ((td->td_proc->p_flag & P_SUGID) != 0)
4083 flags |= O_EXCL;
4084
4085 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name);
4086 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
4087 NULL);
4088 if (error == 0) {
4089 *vpp = nd.ni_vp;
4090 NDFREE_PNBUF(&nd);
4091 }
4092 }
4093
4094 if (error != 0) {
4095 #ifdef AUDIT
4096 audit_proc_coredump(td, name, error);
4097 #endif
4098 free(name, M_TEMP);
4099 return (error);
4100 }
4101 *namep = name;
4102 return (0);
4103 }
4104
4105 /*
4106 * Dump a process' core. The main routine does some
4107 * policy checking, and creates the name of the coredump;
4108 * then it passes on a vnode and a size limit to the process-specific
4109 * coredump routine if there is one; if there _is not_ one, it returns
4110 * ENOSYS; otherwise it returns the error from the process-specific routine.
4111 */
4112
4113 static int
coredump(struct thread * td)4114 coredump(struct thread *td)
4115 {
4116 struct proc *p = td->td_proc;
4117 struct ucred *cred = td->td_ucred;
4118 struct vnode *vp;
4119 struct flock lf;
4120 struct vattr vattr;
4121 size_t fullpathsize;
4122 int error, error1, locked;
4123 char *name; /* name of corefile */
4124 void *rl_cookie;
4125 off_t limit;
4126 char *fullpath, *freepath = NULL;
4127 struct sbuf *sb;
4128
4129 PROC_LOCK_ASSERT(p, MA_OWNED);
4130 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
4131
4132 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
4133 (p->p_flag2 & P2_NOTRACE) != 0) {
4134 PROC_UNLOCK(p);
4135 return (EFAULT);
4136 }
4137
4138 /*
4139 * Note that the bulk of limit checking is done after
4140 * the corefile is created. The exception is if the limit
4141 * for corefiles is 0, in which case we don't bother
4142 * creating the corefile at all. This layout means that
4143 * a corefile is truncated instead of not being created,
4144 * if it is larger than the limit.
4145 */
4146 limit = (off_t)lim_cur(td, RLIMIT_CORE);
4147 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
4148 PROC_UNLOCK(p);
4149 return (EFBIG);
4150 }
4151 PROC_UNLOCK(p);
4152
4153 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
4154 compress_user_cores, p->p_sig, &vp, &name);
4155 if (error != 0)
4156 return (error);
4157
4158 /*
4159 * Don't dump to non-regular files or files with links.
4160 * Do not dump into system files. Effective user must own the corefile.
4161 */
4162 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
4163 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 ||
4164 vattr.va_uid != cred->cr_uid) {
4165 VOP_UNLOCK(vp);
4166 error = EFAULT;
4167 goto out;
4168 }
4169
4170 VOP_UNLOCK(vp);
4171
4172 /* Postpone other writers, including core dumps of other processes. */
4173 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
4174
4175 lf.l_whence = SEEK_SET;
4176 lf.l_start = 0;
4177 lf.l_len = 0;
4178 lf.l_type = F_WRLCK;
4179 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
4180
4181 VATTR_NULL(&vattr);
4182 vattr.va_size = 0;
4183 if (set_core_nodump_flag)
4184 vattr.va_flags = UF_NODUMP;
4185 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4186 VOP_SETATTR(vp, &vattr, cred);
4187 VOP_UNLOCK(vp);
4188 PROC_LOCK(p);
4189 p->p_acflag |= ACORE;
4190 PROC_UNLOCK(p);
4191
4192 if (p->p_sysent->sv_coredump != NULL) {
4193 error = p->p_sysent->sv_coredump(td, vp, limit, 0);
4194 } else {
4195 error = ENOSYS;
4196 }
4197
4198 if (locked) {
4199 lf.l_type = F_UNLCK;
4200 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
4201 }
4202 vn_rangelock_unlock(vp, rl_cookie);
4203
4204 /*
4205 * Notify the userland helper that a process triggered a core dump.
4206 * This allows the helper to run an automated debugging session.
4207 */
4208 if (error != 0 || coredump_devctl == 0)
4209 goto out;
4210 sb = sbuf_new_auto();
4211 if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0)
4212 goto out2;
4213 sbuf_cat(sb, "comm=\"");
4214 devctl_safe_quote_sb(sb, fullpath);
4215 free(freepath, M_TEMP);
4216 sbuf_cat(sb, "\" core=\"");
4217
4218 /*
4219 * We can't lookup core file vp directly. When we're replacing a core, and
4220 * other random times, we flush the name cache, so it will fail. Instead,
4221 * if the path of the core is relative, add the current dir in front if it.
4222 */
4223 if (name[0] != '/') {
4224 fullpathsize = MAXPATHLEN;
4225 freepath = malloc(fullpathsize, M_TEMP, M_WAITOK);
4226 if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) {
4227 free(freepath, M_TEMP);
4228 goto out2;
4229 }
4230 devctl_safe_quote_sb(sb, fullpath);
4231 free(freepath, M_TEMP);
4232 sbuf_putc(sb, '/');
4233 }
4234 devctl_safe_quote_sb(sb, name);
4235 sbuf_putc(sb, '"');
4236 if (sbuf_finish(sb) == 0)
4237 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb));
4238 out2:
4239 sbuf_delete(sb);
4240 out:
4241 error1 = vn_close(vp, FWRITE, cred, td);
4242 if (error == 0)
4243 error = error1;
4244 #ifdef AUDIT
4245 audit_proc_coredump(td, name, error);
4246 #endif
4247 free(name, M_TEMP);
4248 return (error);
4249 }
4250
4251 /*
4252 * Nonexistent system call-- signal process (may want to handle it). Flag
4253 * error in case process won't see signal immediately (blocked or ignored).
4254 */
4255 #ifndef _SYS_SYSPROTO_H_
4256 struct nosys_args {
4257 int dummy;
4258 };
4259 #endif
4260 /* ARGSUSED */
4261 int
nosys(struct thread * td,struct nosys_args * args)4262 nosys(struct thread *td, struct nosys_args *args)
4263 {
4264 struct proc *p;
4265
4266 p = td->td_proc;
4267
4268 if (SV_PROC_FLAG(p, SV_SIGSYS) != 0 && kern_signosys) {
4269 PROC_LOCK(p);
4270 tdsignal(td, SIGSYS);
4271 PROC_UNLOCK(p);
4272 }
4273 if (kern_lognosys == 1 || kern_lognosys == 3) {
4274 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
4275 td->td_sa.code);
4276 }
4277 if (kern_lognosys == 2 || kern_lognosys == 3 ||
4278 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
4279 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
4280 td->td_sa.code);
4281 }
4282 return (ENOSYS);
4283 }
4284
4285 /*
4286 * Send a SIGIO or SIGURG signal to a process or process group using stored
4287 * credentials rather than those of the current process.
4288 */
4289 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)4290 pgsigio(struct sigio **sigiop, int sig, int checkctty)
4291 {
4292 ksiginfo_t ksi;
4293 struct sigio *sigio;
4294
4295 ksiginfo_init(&ksi);
4296 ksi.ksi_signo = sig;
4297 ksi.ksi_code = SI_KERNEL;
4298
4299 SIGIO_LOCK();
4300 sigio = *sigiop;
4301 if (sigio == NULL) {
4302 SIGIO_UNLOCK();
4303 return;
4304 }
4305 if (sigio->sio_pgid > 0) {
4306 PROC_LOCK(sigio->sio_proc);
4307 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
4308 kern_psignal(sigio->sio_proc, sig);
4309 PROC_UNLOCK(sigio->sio_proc);
4310 } else if (sigio->sio_pgid < 0) {
4311 struct proc *p;
4312
4313 PGRP_LOCK(sigio->sio_pgrp);
4314 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
4315 PROC_LOCK(p);
4316 if (p->p_state == PRS_NORMAL &&
4317 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
4318 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
4319 kern_psignal(p, sig);
4320 PROC_UNLOCK(p);
4321 }
4322 PGRP_UNLOCK(sigio->sio_pgrp);
4323 }
4324 SIGIO_UNLOCK();
4325 }
4326
4327 static int
filt_sigattach(struct knote * kn)4328 filt_sigattach(struct knote *kn)
4329 {
4330 struct proc *p = curproc;
4331
4332 kn->kn_ptr.p_proc = p;
4333 kn->kn_flags |= EV_CLEAR; /* automatically set */
4334
4335 knlist_add(p->p_klist, kn, 0);
4336
4337 return (0);
4338 }
4339
4340 static void
filt_sigdetach(struct knote * kn)4341 filt_sigdetach(struct knote *kn)
4342 {
4343 knlist_remove(kn->kn_knlist, kn, 0);
4344 }
4345
4346 /*
4347 * signal knotes are shared with proc knotes, so we apply a mask to
4348 * the hint in order to differentiate them from process hints. This
4349 * could be avoided by using a signal-specific knote list, but probably
4350 * isn't worth the trouble.
4351 */
4352 static int
filt_signal(struct knote * kn,long hint)4353 filt_signal(struct knote *kn, long hint)
4354 {
4355
4356 if (hint & NOTE_SIGNAL) {
4357 hint &= ~NOTE_SIGNAL;
4358
4359 if (kn->kn_id == hint)
4360 kn->kn_data++;
4361 }
4362 return (kn->kn_data != 0);
4363 }
4364
4365 struct sigacts *
sigacts_alloc(void)4366 sigacts_alloc(void)
4367 {
4368 struct sigacts *ps;
4369
4370 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
4371 refcount_init(&ps->ps_refcnt, 1);
4372 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
4373 return (ps);
4374 }
4375
4376 void
sigacts_free(struct sigacts * ps)4377 sigacts_free(struct sigacts *ps)
4378 {
4379
4380 if (refcount_release(&ps->ps_refcnt) == 0)
4381 return;
4382 mtx_destroy(&ps->ps_mtx);
4383 free(ps, M_SUBPROC);
4384 }
4385
4386 struct sigacts *
sigacts_hold(struct sigacts * ps)4387 sigacts_hold(struct sigacts *ps)
4388 {
4389
4390 refcount_acquire(&ps->ps_refcnt);
4391 return (ps);
4392 }
4393
4394 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)4395 sigacts_copy(struct sigacts *dest, struct sigacts *src)
4396 {
4397
4398 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
4399 mtx_lock(&src->ps_mtx);
4400 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
4401 mtx_unlock(&src->ps_mtx);
4402 }
4403
4404 int
sigacts_shared(struct sigacts * ps)4405 sigacts_shared(struct sigacts *ps)
4406 {
4407
4408 return (ps->ps_refcnt > 1);
4409 }
4410
4411 void
sig_drop_caught(struct proc * p)4412 sig_drop_caught(struct proc *p)
4413 {
4414 int sig;
4415 struct sigacts *ps;
4416
4417 ps = p->p_sigacts;
4418 PROC_LOCK_ASSERT(p, MA_OWNED);
4419 mtx_assert(&ps->ps_mtx, MA_OWNED);
4420 SIG_FOREACH(sig, &ps->ps_sigcatch) {
4421 sigdflt(ps, sig);
4422 if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
4423 sigqueue_delete_proc(p, sig);
4424 }
4425 }
4426
4427 static void
sigfastblock_failed(struct thread * td,bool sendsig,bool write)4428 sigfastblock_failed(struct thread *td, bool sendsig, bool write)
4429 {
4430 ksiginfo_t ksi;
4431
4432 /*
4433 * Prevent further fetches and SIGSEGVs, allowing thread to
4434 * issue syscalls despite corruption.
4435 */
4436 sigfastblock_clear(td);
4437
4438 if (!sendsig)
4439 return;
4440 ksiginfo_init_trap(&ksi);
4441 ksi.ksi_signo = SIGSEGV;
4442 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR;
4443 ksi.ksi_addr = td->td_sigblock_ptr;
4444 trapsignal(td, &ksi);
4445 }
4446
4447 static bool
sigfastblock_fetch_sig(struct thread * td,bool sendsig,uint32_t * valp)4448 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp)
4449 {
4450 uint32_t res;
4451
4452 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4453 return (true);
4454 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) {
4455 sigfastblock_failed(td, sendsig, false);
4456 return (false);
4457 }
4458 *valp = res;
4459 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS;
4460 return (true);
4461 }
4462
4463 static void
sigfastblock_resched(struct thread * td,bool resched)4464 sigfastblock_resched(struct thread *td, bool resched)
4465 {
4466 struct proc *p;
4467
4468 if (resched) {
4469 p = td->td_proc;
4470 PROC_LOCK(p);
4471 reschedule_signals(p, td->td_sigmask, 0);
4472 PROC_UNLOCK(p);
4473 }
4474 ast_sched(td, TDA_SIG);
4475 }
4476
4477 int
sys_sigfastblock(struct thread * td,struct sigfastblock_args * uap)4478 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap)
4479 {
4480 struct proc *p;
4481 int error, res;
4482 uint32_t oldval;
4483
4484 error = 0;
4485 p = td->td_proc;
4486 switch (uap->cmd) {
4487 case SIGFASTBLOCK_SETPTR:
4488 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
4489 error = EBUSY;
4490 break;
4491 }
4492 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) {
4493 error = EINVAL;
4494 break;
4495 }
4496 td->td_pflags |= TDP_SIGFASTBLOCK;
4497 td->td_sigblock_ptr = uap->ptr;
4498 break;
4499
4500 case SIGFASTBLOCK_UNBLOCK:
4501 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4502 error = EINVAL;
4503 break;
4504 }
4505
4506 for (;;) {
4507 res = casueword32(td->td_sigblock_ptr,
4508 SIGFASTBLOCK_PEND, &oldval, 0);
4509 if (res == -1) {
4510 error = EFAULT;
4511 sigfastblock_failed(td, false, true);
4512 break;
4513 }
4514 if (res == 0)
4515 break;
4516 MPASS(res == 1);
4517 if (oldval != SIGFASTBLOCK_PEND) {
4518 error = EBUSY;
4519 break;
4520 }
4521 error = thread_check_susp(td, false);
4522 if (error != 0)
4523 break;
4524 }
4525 if (error != 0)
4526 break;
4527
4528 /*
4529 * td_sigblock_val is cleared there, but not on a
4530 * syscall exit. The end effect is that a single
4531 * interruptible sleep, while user sigblock word is
4532 * set, might return EINTR or ERESTART to usermode
4533 * without delivering signal. All further sleeps,
4534 * until userspace clears the word and does
4535 * sigfastblock(UNBLOCK), observe current word and no
4536 * longer get interrupted. It is slight
4537 * non-conformance, with alternative to have read the
4538 * sigblock word on each syscall entry.
4539 */
4540 td->td_sigblock_val = 0;
4541
4542 /*
4543 * Rely on normal ast mechanism to deliver pending
4544 * signals to current thread. But notify others about
4545 * fake unblock.
4546 */
4547 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1);
4548
4549 break;
4550
4551 case SIGFASTBLOCK_UNSETPTR:
4552 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4553 error = EINVAL;
4554 break;
4555 }
4556 if (!sigfastblock_fetch_sig(td, false, &oldval)) {
4557 error = EFAULT;
4558 break;
4559 }
4560 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) {
4561 error = EBUSY;
4562 break;
4563 }
4564 sigfastblock_clear(td);
4565 break;
4566
4567 default:
4568 error = EINVAL;
4569 break;
4570 }
4571 return (error);
4572 }
4573
4574 void
sigfastblock_clear(struct thread * td)4575 sigfastblock_clear(struct thread *td)
4576 {
4577 bool resched;
4578
4579 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4580 return;
4581 td->td_sigblock_val = 0;
4582 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 ||
4583 SIGPENDING(td);
4584 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING);
4585 sigfastblock_resched(td, resched);
4586 }
4587
4588 void
sigfastblock_fetch(struct thread * td)4589 sigfastblock_fetch(struct thread *td)
4590 {
4591 uint32_t val;
4592
4593 (void)sigfastblock_fetch_sig(td, true, &val);
4594 }
4595
4596 static void
sigfastblock_setpend1(struct thread * td)4597 sigfastblock_setpend1(struct thread *td)
4598 {
4599 int res;
4600 uint32_t oldval;
4601
4602 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0)
4603 return;
4604 res = fueword32((void *)td->td_sigblock_ptr, &oldval);
4605 if (res == -1) {
4606 sigfastblock_failed(td, true, false);
4607 return;
4608 }
4609 for (;;) {
4610 res = casueword32(td->td_sigblock_ptr, oldval, &oldval,
4611 oldval | SIGFASTBLOCK_PEND);
4612 if (res == -1) {
4613 sigfastblock_failed(td, true, true);
4614 return;
4615 }
4616 if (res == 0) {
4617 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS;
4618 td->td_pflags &= ~TDP_SIGFASTPENDING;
4619 break;
4620 }
4621 MPASS(res == 1);
4622 if (thread_check_susp(td, false) != 0)
4623 break;
4624 }
4625 }
4626
4627 static void
sigfastblock_setpend(struct thread * td,bool resched)4628 sigfastblock_setpend(struct thread *td, bool resched)
4629 {
4630 struct proc *p;
4631
4632 sigfastblock_setpend1(td);
4633 if (resched) {
4634 p = td->td_proc;
4635 PROC_LOCK(p);
4636 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
4637 PROC_UNLOCK(p);
4638 }
4639 }
4640