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 bool sig_suspend_threads(struct thread *, struct proc *);
112 static int filt_sigattach(struct knote *kn);
113 static void filt_sigdetach(struct knote *kn);
114 static int filt_signal(struct knote *kn, long hint);
115 static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock);
116 static void sigqueue_start(void);
117 static void sigfastblock_setpend(struct thread *td, bool resched);
118 static void sig_handle_first_stop(struct thread *td, struct proc *p,
119 int sig);
120
121 static uma_zone_t ksiginfo_zone = NULL;
122 const struct filterops sig_filtops = {
123 .f_isfd = 0,
124 .f_attach = filt_sigattach,
125 .f_detach = filt_sigdetach,
126 .f_event = filt_signal,
127 };
128
129 static int kern_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 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,
1661 "sigsusp", 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 PROC_SLOCK(p);
2377 sig_handle_first_stop(NULL, p, sig);
2378 PROC_SUNLOCK(p);
2379 return (0);
2380 }
2381
2382 /*
2383 * If sending a tty stop signal to a member of an orphaned
2384 * process group, discard the signal here if the action
2385 * is default; don't stop the process below if sleeping,
2386 * and don't clear any pending SIGCONT.
2387 */
2388 if ((prop & SIGPROP_TTYSTOP) != 0 &&
2389 (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 &&
2390 action == SIG_DFL) {
2391 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0)
2392 ksiginfo_tryfree(ksi);
2393 return (0);
2394 }
2395 sigqueue_delete_proc(p, SIGCONT);
2396 if (p->p_flag & P_CONTINUED) {
2397 p->p_flag &= ~P_CONTINUED;
2398 PROC_LOCK(p->p_pptr);
2399 sigqueue_take(p->p_ksi);
2400 PROC_UNLOCK(p->p_pptr);
2401 }
2402 }
2403
2404 ret = sigqueue_add(sigqueue, sig, ksi);
2405 if (ret != 0)
2406 return (ret);
2407 signotify(td);
2408 /*
2409 * Defer further processing for signals which are held,
2410 * except that stopped processes must be continued by SIGCONT.
2411 */
2412 if (action == SIG_HOLD &&
2413 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG)))
2414 return (0);
2415
2416 /*
2417 * Some signals have a process-wide effect and a per-thread
2418 * component. Most processing occurs when the process next
2419 * tries to cross the user boundary, however there are some
2420 * times when processing needs to be done immediately, such as
2421 * waking up threads so that they can cross the user boundary.
2422 * We try to do the per-process part here.
2423 */
2424 if (P_SHOULDSTOP(p)) {
2425 KASSERT(!(p->p_flag & P_WEXIT),
2426 ("signal to stopped but exiting process"));
2427 if (sig == SIGKILL) {
2428 /*
2429 * If traced process is already stopped,
2430 * then no further action is necessary.
2431 */
2432 if (p->p_flag & P_TRACED)
2433 return (0);
2434 /*
2435 * SIGKILL sets process running.
2436 * It will die elsewhere.
2437 * All threads must be restarted.
2438 */
2439 p->p_flag &= ~P_STOPPED_SIG;
2440 goto runfast;
2441 }
2442
2443 if (prop & SIGPROP_CONT) {
2444 /*
2445 * If traced process is already stopped,
2446 * then no further action is necessary.
2447 */
2448 if (p->p_flag & P_TRACED)
2449 return (0);
2450 /*
2451 * If SIGCONT is default (or ignored), we continue the
2452 * process but don't leave the signal in sigqueue as
2453 * it has no further action. If SIGCONT is held, we
2454 * continue the process and leave the signal in
2455 * sigqueue. If the process catches SIGCONT, let it
2456 * handle the signal itself. If it isn't waiting on
2457 * an event, it goes back to run state.
2458 * Otherwise, process goes back to sleep state.
2459 */
2460 p->p_flag &= ~P_STOPPED_SIG;
2461 PROC_SLOCK(p);
2462 if (p->p_numthreads == p->p_suspcount) {
2463 PROC_SUNLOCK(p);
2464 PROC_LOCK(p->p_pptr);
2465 childproc_continued(p);
2466 PROC_UNLOCK(p->p_pptr);
2467 PROC_SLOCK(p);
2468 }
2469 if (action == SIG_DFL) {
2470 thread_unsuspend(p);
2471 PROC_SUNLOCK(p);
2472 sigqueue_delete(sigqueue, sig);
2473 goto out_cont;
2474 }
2475 if (action == SIG_CATCH) {
2476 /*
2477 * The process wants to catch it so it needs
2478 * to run at least one thread, but which one?
2479 */
2480 PROC_SUNLOCK(p);
2481 goto runfast;
2482 }
2483 /*
2484 * The signal is not ignored or caught.
2485 */
2486 thread_unsuspend(p);
2487 PROC_SUNLOCK(p);
2488 goto out_cont;
2489 }
2490
2491 if (prop & SIGPROP_STOP) {
2492 /*
2493 * If traced process is already stopped,
2494 * then no further action is necessary.
2495 */
2496 if (p->p_flag & P_TRACED)
2497 return (0);
2498 /*
2499 * Already stopped, don't need to stop again
2500 * (If we did the shell could get confused).
2501 * Just make sure the signal STOP bit set.
2502 */
2503 p->p_flag |= P_STOPPED_SIG;
2504 sigqueue_delete(sigqueue, sig);
2505 return (0);
2506 }
2507
2508 /*
2509 * All other kinds of signals:
2510 * If a thread is sleeping interruptibly, simulate a
2511 * wakeup so that when it is continued it will be made
2512 * runnable and can look at the signal. However, don't make
2513 * the PROCESS runnable, leave it stopped.
2514 * It may run a bit until it hits a thread_suspend_check().
2515 */
2516 PROC_SLOCK(p);
2517 thread_lock(td);
2518 if (TD_CAN_ABORT(td))
2519 sig_sleepq_abort(td, intrval);
2520 else
2521 thread_unlock(td);
2522 PROC_SUNLOCK(p);
2523 return (0);
2524 /*
2525 * Mutexes are short lived. Threads waiting on them will
2526 * hit thread_suspend_check() soon.
2527 */
2528 } else if (p->p_state == PRS_NORMAL) {
2529 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
2530 tdsigwakeup(td, sig, action, intrval);
2531 return (0);
2532 }
2533
2534 MPASS(action == SIG_DFL);
2535
2536 if (prop & SIGPROP_STOP) {
2537 if (p->p_flag & (P_PPWAIT|P_WEXIT))
2538 return (0);
2539 p->p_flag |= P_STOPPED_SIG;
2540 p->p_xsig = sig;
2541 PROC_SLOCK(p);
2542 sig_suspend_threads(td, p);
2543 if (p->p_numthreads == p->p_suspcount) {
2544 /*
2545 * only thread sending signal to another
2546 * process can reach here, if thread is sending
2547 * signal to its process, because thread does
2548 * not suspend itself here, p_numthreads
2549 * should never be equal to p_suspcount.
2550 */
2551 thread_stopped(p);
2552 PROC_SUNLOCK(p);
2553 sigqueue_delete_proc(p, p->p_xsig);
2554 } else
2555 PROC_SUNLOCK(p);
2556 return (0);
2557 }
2558 } else {
2559 /* Not in "NORMAL" state. discard the signal. */
2560 sigqueue_delete(sigqueue, sig);
2561 return (0);
2562 }
2563
2564 /*
2565 * The process is not stopped so we need to apply the signal to all the
2566 * running threads.
2567 */
2568 runfast:
2569 tdsigwakeup(td, sig, action, intrval);
2570 PROC_SLOCK(p);
2571 thread_unsuspend(p);
2572 PROC_SUNLOCK(p);
2573 out_cont:
2574 itimer_proc_continue(p);
2575 kqtimer_proc_continue(p);
2576
2577 return (0);
2578 }
2579
2580 /*
2581 * The force of a signal has been directed against a single
2582 * thread. We need to see what we can do about knocking it
2583 * out of any sleep it may be in etc.
2584 */
2585 static void
tdsigwakeup(struct thread * td,int sig,sig_t action,int intrval)2586 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
2587 {
2588 struct proc *p = td->td_proc;
2589 int prop;
2590
2591 PROC_LOCK_ASSERT(p, MA_OWNED);
2592 prop = sigprop(sig);
2593
2594 PROC_SLOCK(p);
2595 thread_lock(td);
2596 /*
2597 * Bring the priority of a thread up if we want it to get
2598 * killed in this lifetime. Be careful to avoid bumping the
2599 * priority of the idle thread, since we still allow to signal
2600 * kernel processes.
2601 */
2602 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 &&
2603 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2604 sched_prio(td, PUSER);
2605 if (TD_ON_SLEEPQ(td)) {
2606 /*
2607 * If thread is sleeping uninterruptibly
2608 * we can't interrupt the sleep... the signal will
2609 * be noticed when the process returns through
2610 * trap() or syscall().
2611 */
2612 if ((td->td_flags & TDF_SINTR) == 0)
2613 goto out;
2614 /*
2615 * If SIGCONT is default (or ignored) and process is
2616 * asleep, we are finished; the process should not
2617 * be awakened.
2618 */
2619 if ((prop & SIGPROP_CONT) && action == SIG_DFL) {
2620 thread_unlock(td);
2621 PROC_SUNLOCK(p);
2622 sigqueue_delete(&p->p_sigqueue, sig);
2623 /*
2624 * It may be on either list in this state.
2625 * Remove from both for now.
2626 */
2627 sigqueue_delete(&td->td_sigqueue, sig);
2628 return;
2629 }
2630
2631 /*
2632 * Don't awaken a sleeping thread for SIGSTOP if the
2633 * STOP signal is deferred.
2634 */
2635 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
2636 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
2637 goto out;
2638
2639 /*
2640 * Give low priority threads a better chance to run.
2641 */
2642 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
2643 sched_prio(td, PUSER);
2644
2645 sig_sleepq_abort(td, intrval);
2646 PROC_SUNLOCK(p);
2647 return;
2648 }
2649
2650 /*
2651 * Other states do nothing with the signal immediately,
2652 * other than kicking ourselves if we are running.
2653 * It will either never be noticed, or noticed very soon.
2654 */
2655 #ifdef SMP
2656 if (TD_IS_RUNNING(td) && td != curthread)
2657 forward_signal(td);
2658 #endif
2659
2660 out:
2661 PROC_SUNLOCK(p);
2662 thread_unlock(td);
2663 }
2664
2665 static void
ptrace_coredumpreq(struct thread * td,struct proc * p,struct thr_coredump_req * tcq)2666 ptrace_coredumpreq(struct thread *td, struct proc *p,
2667 struct thr_coredump_req *tcq)
2668 {
2669 void *rl_cookie;
2670
2671 if (p->p_sysent->sv_coredump == NULL) {
2672 tcq->tc_error = ENOSYS;
2673 return;
2674 }
2675
2676 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX);
2677 tcq->tc_error = p->p_sysent->sv_coredump(td, tcq->tc_vp,
2678 tcq->tc_limit, tcq->tc_flags);
2679 vn_rangelock_unlock(tcq->tc_vp, rl_cookie);
2680 }
2681
2682 static void
ptrace_syscallreq(struct thread * td,struct proc * p,struct thr_syscall_req * tsr)2683 ptrace_syscallreq(struct thread *td, struct proc *p,
2684 struct thr_syscall_req *tsr)
2685 {
2686 struct sysentvec *sv;
2687 struct sysent *se;
2688 register_t rv_saved[2];
2689 int error, nerror;
2690 int sc;
2691 bool audited, sy_thr_static;
2692
2693 sv = p->p_sysent;
2694 if (sv->sv_table == NULL || sv->sv_size < tsr->ts_sa.code) {
2695 tsr->ts_ret.sr_error = ENOSYS;
2696 return;
2697 }
2698
2699 sc = tsr->ts_sa.code;
2700 if (sc == SYS_syscall || sc == SYS___syscall) {
2701 sc = tsr->ts_sa.args[0];
2702 memmove(&tsr->ts_sa.args[0], &tsr->ts_sa.args[1],
2703 sizeof(register_t) * (tsr->ts_nargs - 1));
2704 }
2705
2706 tsr->ts_sa.callp = se = &sv->sv_table[sc];
2707
2708 VM_CNT_INC(v_syscall);
2709 td->td_pticks = 0;
2710 if (__predict_false(td->td_cowgen != atomic_load_int(
2711 &td->td_proc->p_cowgen)))
2712 thread_cow_update(td);
2713
2714 td->td_sa = tsr->ts_sa;
2715
2716 #ifdef CAPABILITY_MODE
2717 if ((se->sy_flags & SYF_CAPENABLED) == 0) {
2718 if (CAP_TRACING(td))
2719 ktrcapfail(CAPFAIL_SYSCALL, NULL);
2720 if (IN_CAPABILITY_MODE(td)) {
2721 tsr->ts_ret.sr_error = ECAPMODE;
2722 return;
2723 }
2724 }
2725 #endif
2726
2727 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2728 audited = AUDIT_SYSCALL_ENTER(sc, td) != 0;
2729
2730 if (!sy_thr_static) {
2731 error = syscall_thread_enter(td, &se);
2732 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
2733 if (error != 0) {
2734 tsr->ts_ret.sr_error = error;
2735 return;
2736 }
2737 }
2738
2739 rv_saved[0] = td->td_retval[0];
2740 rv_saved[1] = td->td_retval[1];
2741 nerror = td->td_errno;
2742 td->td_retval[0] = 0;
2743 td->td_retval[1] = 0;
2744
2745 #ifdef KDTRACE_HOOKS
2746 if (se->sy_entry != 0)
2747 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_ENTRY, 0);
2748 #endif
2749 tsr->ts_ret.sr_error = se->sy_call(td, tsr->ts_sa.args);
2750 #ifdef KDTRACE_HOOKS
2751 if (se->sy_return != 0)
2752 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_RETURN,
2753 tsr->ts_ret.sr_error != 0 ? -1 : td->td_retval[0]);
2754 #endif
2755
2756 tsr->ts_ret.sr_retval[0] = td->td_retval[0];
2757 tsr->ts_ret.sr_retval[1] = td->td_retval[1];
2758 td->td_retval[0] = rv_saved[0];
2759 td->td_retval[1] = rv_saved[1];
2760 td->td_errno = nerror;
2761
2762 if (audited)
2763 AUDIT_SYSCALL_EXIT(error, td);
2764 if (!sy_thr_static)
2765 syscall_thread_exit(td, se);
2766 }
2767
2768 static void
ptrace_remotereq(struct thread * td,int flag)2769 ptrace_remotereq(struct thread *td, int flag)
2770 {
2771 struct proc *p;
2772
2773 MPASS(td == curthread);
2774 p = td->td_proc;
2775 PROC_LOCK_ASSERT(p, MA_OWNED);
2776 if ((td->td_dbgflags & flag) == 0)
2777 return;
2778 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped"));
2779 KASSERT(td->td_remotereq != NULL, ("td_remotereq is NULL"));
2780
2781 PROC_UNLOCK(p);
2782 switch (flag) {
2783 case TDB_COREDUMPREQ:
2784 ptrace_coredumpreq(td, p, td->td_remotereq);
2785 break;
2786 case TDB_SCREMOTEREQ:
2787 ptrace_syscallreq(td, p, td->td_remotereq);
2788 break;
2789 default:
2790 __unreachable();
2791 }
2792 PROC_LOCK(p);
2793
2794 MPASS((td->td_dbgflags & flag) != 0);
2795 td->td_dbgflags &= ~flag;
2796 td->td_remotereq = NULL;
2797 wakeup(p);
2798 }
2799
2800 /*
2801 * Suspend threads of the process p, either by directly setting the
2802 * inhibitor for the thread sleeping interruptibly, or by making the
2803 * thread suspend at the userspace boundary by scheduling a suspend AST.
2804 *
2805 * Returns true if some threads were suspended directly from the
2806 * sleeping state, and false if all threads are forced to process AST.
2807 */
2808 static bool
sig_suspend_threads(struct thread * td,struct proc * p)2809 sig_suspend_threads(struct thread *td, struct proc *p)
2810 {
2811 struct thread *td2;
2812 bool res;
2813
2814 PROC_LOCK_ASSERT(p, MA_OWNED);
2815 PROC_SLOCK_ASSERT(p, MA_OWNED);
2816
2817 res = false;
2818 FOREACH_THREAD_IN_PROC(p, td2) {
2819 thread_lock(td2);
2820 ast_sched_locked(td2, TDA_SUSPEND);
2821 if (TD_IS_SLEEPING(td2) && (td2->td_flags & TDF_SINTR) != 0) {
2822 if (td2->td_flags & TDF_SBDRY) {
2823 /*
2824 * Once a thread is asleep with
2825 * TDF_SBDRY and without TDF_SERESTART
2826 * or TDF_SEINTR set, it should never
2827 * become suspended due to this check.
2828 */
2829 KASSERT(!TD_IS_SUSPENDED(td2),
2830 ("thread with deferred stops suspended"));
2831 if (TD_SBDRY_INTR(td2)) {
2832 sleepq_abort(td2, TD_SBDRY_ERRNO(td2));
2833 continue;
2834 }
2835 } else if (!TD_IS_SUSPENDED(td2)) {
2836 thread_suspend_one(td2);
2837 res = true;
2838 }
2839 } else if (!TD_IS_SUSPENDED(td2)) {
2840 #ifdef SMP
2841 if (TD_IS_RUNNING(td2) && td2 != td)
2842 forward_signal(td2);
2843 #endif
2844 }
2845 thread_unlock(td2);
2846 }
2847 return (res);
2848 }
2849
2850 static void
sig_handle_first_stop(struct thread * td,struct proc * p,int sig)2851 sig_handle_first_stop(struct thread *td, struct proc *p, int sig)
2852 {
2853 if (td != NULL && (td->td_dbgflags & TDB_FSTP) == 0 &&
2854 ((p->p_flag2 & P2_PTRACE_FSTP) != 0 || p->p_xthread != NULL))
2855 return;
2856
2857 p->p_xsig = sig;
2858 p->p_xthread = td;
2859
2860 /*
2861 * If we are on sleepqueue already, let sleepqueue
2862 * code decide if it needs to go sleep after attach.
2863 */
2864 if (td != NULL && td->td_wchan == NULL)
2865 td->td_dbgflags &= ~TDB_FSTP;
2866
2867 p->p_flag2 &= ~P2_PTRACE_FSTP;
2868 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
2869 if (sig_suspend_threads(td, p) && td == NULL)
2870 thread_stopped(p);
2871 }
2872
2873 /*
2874 * Stop the process for an event deemed interesting to the debugger. If si is
2875 * non-NULL, this is a signal exchange; the new signal requested by the
2876 * debugger will be returned for handling. If si is NULL, this is some other
2877 * type of interesting event. The debugger may request a signal be delivered in
2878 * that case as well, however it will be deferred until it can be handled.
2879 */
2880 int
ptracestop(struct thread * td,int sig,ksiginfo_t * si)2881 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
2882 {
2883 struct proc *p = td->td_proc;
2884 struct thread *td2;
2885 ksiginfo_t ksi;
2886
2887 PROC_LOCK_ASSERT(p, MA_OWNED);
2888 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
2889 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
2890 &p->p_mtx.lock_object, "Stopping for traced signal");
2891
2892 td->td_xsig = sig;
2893
2894 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
2895 td->td_dbgflags |= TDB_XSIG;
2896 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
2897 td->td_tid, p->p_pid, td->td_dbgflags, sig);
2898 PROC_SLOCK(p);
2899 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
2900 if (P_KILLED(p)) {
2901 /*
2902 * Ensure that, if we've been PT_KILLed, the
2903 * exit status reflects that. Another thread
2904 * may also be in ptracestop(), having just
2905 * received the SIGKILL, but this thread was
2906 * unsuspended first.
2907 */
2908 td->td_dbgflags &= ~TDB_XSIG;
2909 td->td_xsig = SIGKILL;
2910 p->p_ptevents = 0;
2911 break;
2912 }
2913 if (p->p_flag & P_SINGLE_EXIT &&
2914 !(td->td_dbgflags & TDB_EXIT)) {
2915 /*
2916 * Ignore ptrace stops except for thread exit
2917 * events when the process exits.
2918 */
2919 td->td_dbgflags &= ~TDB_XSIG;
2920 PROC_SUNLOCK(p);
2921 return (0);
2922 }
2923
2924 /*
2925 * Make wait(2) work. Ensure that right after the
2926 * attach, the thread which was decided to become the
2927 * leader of attach gets reported to the waiter.
2928 * Otherwise, just avoid overwriting another thread's
2929 * assignment to p_xthread. If another thread has
2930 * already set p_xthread, the current thread will get
2931 * a chance to report itself upon the next iteration.
2932 */
2933 sig_handle_first_stop(td, p, sig);
2934
2935 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
2936 td->td_dbgflags &= ~TDB_STOPATFORK;
2937 }
2938 stopme:
2939 td->td_dbgflags |= TDB_SSWITCH;
2940 thread_suspend_switch(td, p);
2941 td->td_dbgflags &= ~TDB_SSWITCH;
2942 if ((td->td_dbgflags & (TDB_COREDUMPREQ |
2943 TDB_SCREMOTEREQ)) != 0) {
2944 MPASS((td->td_dbgflags & (TDB_COREDUMPREQ |
2945 TDB_SCREMOTEREQ)) !=
2946 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2947 PROC_SUNLOCK(p);
2948 ptrace_remotereq(td, td->td_dbgflags &
2949 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ));
2950 PROC_SLOCK(p);
2951 goto stopme;
2952 }
2953 if (p->p_xthread == td)
2954 p->p_xthread = NULL;
2955 if (!(p->p_flag & P_TRACED))
2956 break;
2957 if (td->td_dbgflags & TDB_SUSPEND) {
2958 if (p->p_flag & P_SINGLE_EXIT)
2959 break;
2960 goto stopme;
2961 }
2962 }
2963 PROC_SUNLOCK(p);
2964 }
2965
2966 if (si != NULL && sig == td->td_xsig) {
2967 /* Parent wants us to take the original signal unchanged. */
2968 si->ksi_flags |= KSI_HEAD;
2969 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
2970 si->ksi_signo = 0;
2971 } else if (td->td_xsig != 0) {
2972 /*
2973 * If parent wants us to take a new signal, then it will leave
2974 * it in td->td_xsig; otherwise we just look for signals again.
2975 */
2976 ksiginfo_init(&ksi);
2977 ksi.ksi_signo = td->td_xsig;
2978 ksi.ksi_flags |= KSI_PTRACE;
2979 td2 = sigtd(p, td->td_xsig, false);
2980 tdsendsignal(p, td2, td->td_xsig, &ksi);
2981 if (td != td2)
2982 return (0);
2983 }
2984
2985 return (td->td_xsig);
2986 }
2987
2988 static void
reschedule_signals(struct proc * p,sigset_t block,int flags)2989 reschedule_signals(struct proc *p, sigset_t block, int flags)
2990 {
2991 struct sigacts *ps;
2992 struct thread *td;
2993 int sig;
2994 bool fastblk, pslocked;
2995
2996 PROC_LOCK_ASSERT(p, MA_OWNED);
2997 ps = p->p_sigacts;
2998 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0;
2999 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED);
3000 if (SIGISEMPTY(p->p_siglist))
3001 return;
3002 SIGSETAND(block, p->p_siglist);
3003 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0;
3004 SIG_FOREACH(sig, &block) {
3005 td = sigtd(p, sig, fastblk);
3006
3007 /*
3008 * If sigtd() selected us despite sigfastblock is
3009 * blocking, do not activate AST or wake us, to avoid
3010 * loop in AST handler.
3011 */
3012 if (fastblk && td == curthread)
3013 continue;
3014
3015 signotify(td);
3016 if (!pslocked)
3017 mtx_lock(&ps->ps_mtx);
3018 if (p->p_flag & P_TRACED ||
3019 (SIGISMEMBER(ps->ps_sigcatch, sig) &&
3020 !SIGISMEMBER(td->td_sigmask, sig))) {
3021 tdsigwakeup(td, sig, SIG_CATCH,
3022 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
3023 ERESTART));
3024 }
3025 if (!pslocked)
3026 mtx_unlock(&ps->ps_mtx);
3027 }
3028 }
3029
3030 void
tdsigcleanup(struct thread * td)3031 tdsigcleanup(struct thread *td)
3032 {
3033 struct proc *p;
3034 sigset_t unblocked;
3035
3036 p = td->td_proc;
3037 PROC_LOCK_ASSERT(p, MA_OWNED);
3038
3039 sigqueue_flush(&td->td_sigqueue);
3040 if (p->p_numthreads == 1)
3041 return;
3042
3043 /*
3044 * Since we cannot handle signals, notify signal post code
3045 * about this by filling the sigmask.
3046 *
3047 * Also, if needed, wake up thread(s) that do not block the
3048 * same signals as the exiting thread, since the thread might
3049 * have been selected for delivery and woken up.
3050 */
3051 SIGFILLSET(unblocked);
3052 SIGSETNAND(unblocked, td->td_sigmask);
3053 SIGFILLSET(td->td_sigmask);
3054 reschedule_signals(p, unblocked, 0);
3055
3056 }
3057
3058 static int
sigdeferstop_curr_flags(int cflags)3059 sigdeferstop_curr_flags(int cflags)
3060 {
3061
3062 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
3063 (cflags & TDF_SBDRY) != 0);
3064 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
3065 }
3066
3067 /*
3068 * Defer the delivery of SIGSTOP for the current thread, according to
3069 * the requested mode. Returns previous flags, which must be restored
3070 * by sigallowstop().
3071 *
3072 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
3073 * cleared by the current thread, which allow the lock-less read-only
3074 * accesses below.
3075 */
3076 int
sigdeferstop_impl(int mode)3077 sigdeferstop_impl(int mode)
3078 {
3079 struct thread *td;
3080 int cflags, nflags;
3081
3082 td = curthread;
3083 cflags = sigdeferstop_curr_flags(td->td_flags);
3084 switch (mode) {
3085 case SIGDEFERSTOP_NOP:
3086 nflags = cflags;
3087 break;
3088 case SIGDEFERSTOP_OFF:
3089 nflags = 0;
3090 break;
3091 case SIGDEFERSTOP_SILENT:
3092 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
3093 break;
3094 case SIGDEFERSTOP_EINTR:
3095 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
3096 break;
3097 case SIGDEFERSTOP_ERESTART:
3098 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
3099 break;
3100 default:
3101 panic("sigdeferstop: invalid mode %x", mode);
3102 break;
3103 }
3104 if (cflags == nflags)
3105 return (SIGDEFERSTOP_VAL_NCHG);
3106 thread_lock(td);
3107 td->td_flags = (td->td_flags & ~cflags) | nflags;
3108 thread_unlock(td);
3109 return (cflags);
3110 }
3111
3112 /*
3113 * Restores the STOP handling mode, typically permitting the delivery
3114 * of SIGSTOP for the current thread. This does not immediately
3115 * suspend if a stop was posted. Instead, the thread will suspend
3116 * either via ast() or a subsequent interruptible sleep.
3117 */
3118 void
sigallowstop_impl(int prev)3119 sigallowstop_impl(int prev)
3120 {
3121 struct thread *td;
3122 int cflags;
3123
3124 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
3125 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
3126 ("sigallowstop: incorrect previous mode %x", prev));
3127 td = curthread;
3128 cflags = sigdeferstop_curr_flags(td->td_flags);
3129 if (cflags != prev) {
3130 thread_lock(td);
3131 td->td_flags = (td->td_flags & ~cflags) | prev;
3132 thread_unlock(td);
3133 }
3134 }
3135
3136 enum sigstatus {
3137 SIGSTATUS_HANDLE,
3138 SIGSTATUS_HANDLED,
3139 SIGSTATUS_IGNORE,
3140 SIGSTATUS_SBDRY_STOP,
3141 };
3142
3143 /*
3144 * The thread has signal "sig" pending. Figure out what to do with it:
3145 *
3146 * _HANDLE -> the caller should handle the signal
3147 * _HANDLED -> handled internally, reload pending signal set
3148 * _IGNORE -> ignored, remove from the set of pending signals and try the
3149 * next pending signal
3150 * _SBDRY_STOP -> the signal should stop the thread but this is not
3151 * permitted in the current context
3152 */
3153 static enum sigstatus
sigprocess(struct thread * td,int sig)3154 sigprocess(struct thread *td, int sig)
3155 {
3156 struct proc *p;
3157 struct sigacts *ps;
3158 struct sigqueue *queue;
3159 ksiginfo_t ksi;
3160 int prop;
3161
3162 KASSERT(_SIG_VALID(sig), ("%s: invalid signal %d", __func__, sig));
3163
3164 p = td->td_proc;
3165 ps = p->p_sigacts;
3166 mtx_assert(&ps->ps_mtx, MA_OWNED);
3167 PROC_LOCK_ASSERT(p, MA_OWNED);
3168
3169 /*
3170 * We should allow pending but ignored signals below
3171 * if there is sigwait() active, or P_TRACED was
3172 * on when they were posted.
3173 */
3174 if (SIGISMEMBER(ps->ps_sigignore, sig) &&
3175 (p->p_flag & P_TRACED) == 0 &&
3176 (td->td_flags & TDF_SIGWAIT) == 0) {
3177 return (SIGSTATUS_IGNORE);
3178 }
3179
3180 /*
3181 * If the process is going to single-thread mode to prepare
3182 * for exit, there is no sense in delivering any signal
3183 * to usermode. Another important consequence is that
3184 * msleep(..., PCATCH, ...) now is only interruptible by a
3185 * suspend request.
3186 */
3187 if ((p->p_flag2 & P2_WEXIT) != 0)
3188 return (SIGSTATUS_IGNORE);
3189
3190 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
3191 /*
3192 * If traced, always stop.
3193 * Remove old signal from queue before the stop.
3194 * XXX shrug off debugger, it causes siginfo to
3195 * be thrown away.
3196 */
3197 queue = &td->td_sigqueue;
3198 ksiginfo_init(&ksi);
3199 if (sigqueue_get(queue, sig, &ksi) == 0) {
3200 queue = &p->p_sigqueue;
3201 sigqueue_get(queue, sig, &ksi);
3202 }
3203 td->td_si = ksi.ksi_info;
3204
3205 mtx_unlock(&ps->ps_mtx);
3206 sig = ptracestop(td, sig, &ksi);
3207 mtx_lock(&ps->ps_mtx);
3208
3209 td->td_si.si_signo = 0;
3210
3211 /*
3212 * Keep looking if the debugger discarded or
3213 * replaced the signal.
3214 */
3215 if (sig == 0)
3216 return (SIGSTATUS_HANDLED);
3217
3218 /*
3219 * If the signal became masked, re-queue it.
3220 */
3221 if (SIGISMEMBER(td->td_sigmask, sig)) {
3222 ksi.ksi_flags |= KSI_HEAD;
3223 sigqueue_add(&p->p_sigqueue, sig, &ksi);
3224 return (SIGSTATUS_HANDLED);
3225 }
3226
3227 /*
3228 * If the traced bit got turned off, requeue the signal and
3229 * reload the set of pending signals. This ensures that p_sig*
3230 * and p_sigact are consistent.
3231 */
3232 if ((p->p_flag & P_TRACED) == 0) {
3233 if ((ksi.ksi_flags & KSI_PTRACE) == 0) {
3234 ksi.ksi_flags |= KSI_HEAD;
3235 sigqueue_add(queue, sig, &ksi);
3236 }
3237 return (SIGSTATUS_HANDLED);
3238 }
3239 }
3240
3241 /*
3242 * Decide whether the signal should be returned.
3243 * Return the signal's number, or fall through
3244 * to clear it from the pending mask.
3245 */
3246 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
3247 case (intptr_t)SIG_DFL:
3248 /*
3249 * Don't take default actions on system processes.
3250 */
3251 if (p->p_pid <= 1) {
3252 #ifdef DIAGNOSTIC
3253 /*
3254 * Are you sure you want to ignore SIGSEGV
3255 * in init? XXX
3256 */
3257 printf("Process (pid %lu) got signal %d\n",
3258 (u_long)p->p_pid, sig);
3259 #endif
3260 return (SIGSTATUS_IGNORE);
3261 }
3262
3263 /*
3264 * If there is a pending stop signal to process with
3265 * default action, stop here, then clear the signal.
3266 * Traced or exiting processes should ignore stops.
3267 * Additionally, a member of an orphaned process group
3268 * should ignore tty stops.
3269 */
3270 prop = sigprop(sig);
3271 if (prop & SIGPROP_STOP) {
3272 mtx_unlock(&ps->ps_mtx);
3273 if ((p->p_flag & (P_TRACED | P_WEXIT |
3274 P_SINGLE_EXIT)) != 0 || ((p->p_pgrp->
3275 pg_flags & PGRP_ORPHANED) != 0 &&
3276 (prop & SIGPROP_TTYSTOP) != 0)) {
3277 mtx_lock(&ps->ps_mtx);
3278 return (SIGSTATUS_IGNORE);
3279 }
3280 if (TD_SBDRY_INTR(td)) {
3281 KASSERT((td->td_flags & TDF_SBDRY) != 0,
3282 ("lost TDF_SBDRY"));
3283 mtx_lock(&ps->ps_mtx);
3284 return (SIGSTATUS_SBDRY_STOP);
3285 }
3286 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
3287 &p->p_mtx.lock_object, "Catching SIGSTOP");
3288 sigqueue_delete(&td->td_sigqueue, sig);
3289 sigqueue_delete(&p->p_sigqueue, sig);
3290 p->p_flag |= P_STOPPED_SIG;
3291 p->p_xsig = sig;
3292 PROC_SLOCK(p);
3293 sig_suspend_threads(td, p);
3294 thread_suspend_switch(td, p);
3295 PROC_SUNLOCK(p);
3296 mtx_lock(&ps->ps_mtx);
3297 return (SIGSTATUS_HANDLED);
3298 } else if ((prop & SIGPROP_IGNORE) != 0 &&
3299 (td->td_flags & TDF_SIGWAIT) == 0) {
3300 /*
3301 * Default action is to ignore; drop it if
3302 * not in kern_sigtimedwait().
3303 */
3304 return (SIGSTATUS_IGNORE);
3305 } else {
3306 return (SIGSTATUS_HANDLE);
3307 }
3308
3309 case (intptr_t)SIG_IGN:
3310 if ((td->td_flags & TDF_SIGWAIT) == 0)
3311 return (SIGSTATUS_IGNORE);
3312 else
3313 return (SIGSTATUS_HANDLE);
3314
3315 default:
3316 /*
3317 * This signal has an action, let postsig() process it.
3318 */
3319 return (SIGSTATUS_HANDLE);
3320 }
3321 }
3322
3323 /*
3324 * If the current process has received a signal (should be caught or cause
3325 * termination, should interrupt current syscall), return the signal number.
3326 * Stop signals with default action are processed immediately, then cleared;
3327 * they aren't returned. This is checked after each entry to the system for
3328 * a syscall or trap (though this can usually be done without calling
3329 * issignal by checking the pending signal masks in cursig.) The normal call
3330 * sequence is
3331 *
3332 * while (sig = cursig(curthread))
3333 * postsig(sig);
3334 */
3335 static int
issignal(struct thread * td)3336 issignal(struct thread *td)
3337 {
3338 struct proc *p;
3339 sigset_t sigpending;
3340 int sig;
3341
3342 p = td->td_proc;
3343 PROC_LOCK_ASSERT(p, MA_OWNED);
3344
3345 for (;;) {
3346 sigpending = td->td_sigqueue.sq_signals;
3347 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
3348 SIGSETNAND(sigpending, td->td_sigmask);
3349
3350 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
3351 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
3352 SIG_STOPSIGMASK(sigpending);
3353 if (SIGISEMPTY(sigpending)) /* no signal to send */
3354 return (0);
3355
3356 /*
3357 * Do fast sigblock if requested by usermode. Since
3358 * we do know that there was a signal pending at this
3359 * point, set the FAST_SIGBLOCK_PEND as indicator for
3360 * usermode to perform a dummy call to
3361 * FAST_SIGBLOCK_UNBLOCK, which causes immediate
3362 * delivery of postponed pending signal.
3363 */
3364 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
3365 if (td->td_sigblock_val != 0)
3366 SIGSETNAND(sigpending, fastblock_mask);
3367 if (SIGISEMPTY(sigpending)) {
3368 td->td_pflags |= TDP_SIGFASTPENDING;
3369 return (0);
3370 }
3371 }
3372
3373 if (!pt_attach_transparent &&
3374 (p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
3375 (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
3376 SIGISMEMBER(sigpending, SIGSTOP)) {
3377 /*
3378 * If debugger just attached, always consume
3379 * SIGSTOP from ptrace(PT_ATTACH) first, to
3380 * execute the debugger attach ritual in
3381 * order.
3382 */
3383 td->td_dbgflags |= TDB_FSTP;
3384 SIGEMPTYSET(sigpending);
3385 SIGADDSET(sigpending, SIGSTOP);
3386 }
3387
3388 SIG_FOREACH(sig, &sigpending) {
3389 switch (sigprocess(td, sig)) {
3390 case SIGSTATUS_HANDLE:
3391 return (sig);
3392 case SIGSTATUS_HANDLED:
3393 goto next;
3394 case SIGSTATUS_IGNORE:
3395 sigqueue_delete(&td->td_sigqueue, sig);
3396 sigqueue_delete(&p->p_sigqueue, sig);
3397 break;
3398 case SIGSTATUS_SBDRY_STOP:
3399 return (-1);
3400 }
3401 }
3402 next:;
3403 }
3404 }
3405
3406 void
thread_stopped(struct proc * p)3407 thread_stopped(struct proc *p)
3408 {
3409 int n;
3410
3411 PROC_LOCK_ASSERT(p, MA_OWNED);
3412 PROC_SLOCK_ASSERT(p, MA_OWNED);
3413 n = p->p_suspcount;
3414 if (p == curproc)
3415 n++;
3416 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
3417 PROC_SUNLOCK(p);
3418 p->p_flag &= ~P_WAITED;
3419 PROC_LOCK(p->p_pptr);
3420 childproc_stopped(p, (p->p_flag & P_TRACED) ?
3421 CLD_TRAPPED : CLD_STOPPED);
3422 PROC_UNLOCK(p->p_pptr);
3423 PROC_SLOCK(p);
3424 }
3425 }
3426
3427 /*
3428 * Take the action for the specified signal
3429 * from the current set of pending signals.
3430 */
3431 int
postsig(int sig)3432 postsig(int sig)
3433 {
3434 struct thread *td;
3435 struct proc *p;
3436 struct sigacts *ps;
3437 sig_t action;
3438 ksiginfo_t ksi;
3439 sigset_t returnmask;
3440
3441 KASSERT(sig != 0, ("postsig"));
3442
3443 td = curthread;
3444 p = td->td_proc;
3445 PROC_LOCK_ASSERT(p, MA_OWNED);
3446 ps = p->p_sigacts;
3447 mtx_assert(&ps->ps_mtx, MA_OWNED);
3448 ksiginfo_init(&ksi);
3449 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
3450 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
3451 return (0);
3452 ksi.ksi_signo = sig;
3453 if (ksi.ksi_code == SI_TIMER)
3454 itimer_accept(p, ksi.ksi_timerid, &ksi);
3455 action = ps->ps_sigact[_SIG_IDX(sig)];
3456 #ifdef KTRACE
3457 if (KTRPOINT(td, KTR_PSIG))
3458 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
3459 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
3460 #endif
3461
3462 if (action == SIG_DFL) {
3463 /*
3464 * Default action, where the default is to kill
3465 * the process. (Other cases were ignored above.)
3466 */
3467 mtx_unlock(&ps->ps_mtx);
3468 proc_td_siginfo_capture(td, &ksi.ksi_info);
3469 sigexit(td, sig);
3470 /* NOTREACHED */
3471 } else {
3472 /*
3473 * If we get here, the signal must be caught.
3474 */
3475 KASSERT(action != SIG_IGN, ("postsig action %p", action));
3476 KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
3477 ("postsig action: blocked sig %d", sig));
3478
3479 /*
3480 * Set the new mask value and also defer further
3481 * occurrences of this signal.
3482 *
3483 * Special case: user has done a sigsuspend. Here the
3484 * current mask is not of interest, but rather the
3485 * mask from before the sigsuspend is what we want
3486 * restored after the signal processing is completed.
3487 */
3488 if (td->td_pflags & TDP_OLDMASK) {
3489 returnmask = td->td_oldsigmask;
3490 td->td_pflags &= ~TDP_OLDMASK;
3491 } else
3492 returnmask = td->td_sigmask;
3493
3494 if (p->p_sig == sig) {
3495 p->p_sig = 0;
3496 }
3497 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
3498 postsig_done(sig, td, ps);
3499 }
3500 return (1);
3501 }
3502
3503 int
sig_ast_checksusp(struct thread * td)3504 sig_ast_checksusp(struct thread *td)
3505 {
3506 struct proc *p __diagused;
3507 int ret;
3508
3509 p = td->td_proc;
3510 PROC_LOCK_ASSERT(p, MA_OWNED);
3511
3512 if (!td_ast_pending(td, TDA_SUSPEND))
3513 return (0);
3514
3515 ret = thread_suspend_check(1);
3516 MPASS(ret == 0 || ret == EINTR || ret == ERESTART);
3517 return (ret);
3518 }
3519
3520 int
sig_ast_needsigchk(struct thread * td)3521 sig_ast_needsigchk(struct thread *td)
3522 {
3523 struct proc *p;
3524 struct sigacts *ps;
3525 int ret, sig;
3526
3527 p = td->td_proc;
3528 PROC_LOCK_ASSERT(p, MA_OWNED);
3529
3530 if (!td_ast_pending(td, TDA_SIG))
3531 return (0);
3532
3533 ps = p->p_sigacts;
3534 mtx_lock(&ps->ps_mtx);
3535 sig = cursig(td);
3536 if (sig == -1) {
3537 mtx_unlock(&ps->ps_mtx);
3538 KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY"));
3539 KASSERT(TD_SBDRY_INTR(td),
3540 ("lost TDF_SERESTART of TDF_SEINTR"));
3541 KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) !=
3542 (TDF_SEINTR | TDF_SERESTART),
3543 ("both TDF_SEINTR and TDF_SERESTART"));
3544 ret = TD_SBDRY_ERRNO(td);
3545 } else if (sig != 0) {
3546 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART;
3547 mtx_unlock(&ps->ps_mtx);
3548 } else {
3549 mtx_unlock(&ps->ps_mtx);
3550 ret = 0;
3551 }
3552
3553 /*
3554 * Do not go into sleep if this thread was the ptrace(2)
3555 * attach leader. cursig() consumed SIGSTOP from PT_ATTACH,
3556 * but we usually act on the signal by interrupting sleep, and
3557 * should do that here as well.
3558 */
3559 if ((td->td_dbgflags & TDB_FSTP) != 0) {
3560 if (ret == 0)
3561 ret = EINTR;
3562 td->td_dbgflags &= ~TDB_FSTP;
3563 }
3564
3565 return (ret);
3566 }
3567
3568 int
sig_intr(void)3569 sig_intr(void)
3570 {
3571 struct thread *td;
3572 struct proc *p;
3573 int ret;
3574
3575 td = curthread;
3576 if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND))
3577 return (0);
3578
3579 p = td->td_proc;
3580
3581 PROC_LOCK(p);
3582 ret = sig_ast_checksusp(td);
3583 if (ret == 0)
3584 ret = sig_ast_needsigchk(td);
3585 PROC_UNLOCK(p);
3586 return (ret);
3587 }
3588
3589 bool
curproc_sigkilled(void)3590 curproc_sigkilled(void)
3591 {
3592 struct thread *td;
3593 struct proc *p;
3594 struct sigacts *ps;
3595 bool res;
3596
3597 td = curthread;
3598 if (!td_ast_pending(td, TDA_SIG))
3599 return (false);
3600
3601 p = td->td_proc;
3602 PROC_LOCK(p);
3603 ps = p->p_sigacts;
3604 mtx_lock(&ps->ps_mtx);
3605 res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) ||
3606 SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL);
3607 mtx_unlock(&ps->ps_mtx);
3608 PROC_UNLOCK(p);
3609 return (res);
3610 }
3611
3612 void
proc_wkilled(struct proc * p)3613 proc_wkilled(struct proc *p)
3614 {
3615
3616 PROC_LOCK_ASSERT(p, MA_OWNED);
3617 if ((p->p_flag & P_WKILLED) == 0)
3618 p->p_flag |= P_WKILLED;
3619 }
3620
3621 /*
3622 * Kill the current process for stated reason.
3623 */
3624 void
killproc(struct proc * p,const char * why)3625 killproc(struct proc *p, const char *why)
3626 {
3627
3628 PROC_LOCK_ASSERT(p, MA_OWNED);
3629 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
3630 p->p_comm);
3631 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
3632 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
3633 p->p_ucred->cr_uid, why);
3634 proc_wkilled(p);
3635 kern_psignal(p, SIGKILL);
3636 }
3637
3638 /*
3639 * Force the current process to exit with the specified signal, dumping core
3640 * if appropriate. We bypass the normal tests for masked and caught signals,
3641 * allowing unrecoverable failures to terminate the process without changing
3642 * signal state. Mark the accounting record with the signal termination.
3643 * If dumping core, save the signal number for the debugger. Calls exit and
3644 * does not return.
3645 */
3646 void
sigexit(struct thread * td,int sig)3647 sigexit(struct thread *td, int sig)
3648 {
3649 struct proc *p = td->td_proc;
3650 const char *coreinfo;
3651 int rv;
3652 bool logexit;
3653
3654 PROC_LOCK_ASSERT(p, MA_OWNED);
3655 proc_set_p2_wexit(p);
3656
3657 p->p_acflag |= AXSIG;
3658 if ((p->p_flag2 & P2_LOGSIGEXIT_CTL) == 0)
3659 logexit = kern_logsigexit != 0;
3660 else
3661 logexit = (p->p_flag2 & P2_LOGSIGEXIT_ENABLE) != 0;
3662
3663 /*
3664 * We must be single-threading to generate a core dump. This
3665 * ensures that the registers in the core file are up-to-date.
3666 * Also, the ELF dump handler assumes that the thread list doesn't
3667 * change out from under it.
3668 *
3669 * XXX If another thread attempts to single-thread before us
3670 * (e.g. via fork()), we won't get a dump at all.
3671 */
3672 if ((sigprop(sig) & SIGPROP_CORE) &&
3673 thread_single(p, SINGLE_NO_EXIT) == 0) {
3674 p->p_sig = sig;
3675 /*
3676 * Log signals which would cause core dumps
3677 * (Log as LOG_INFO to appease those who don't want
3678 * these messages.)
3679 * XXX : Todo, as well as euid, write out ruid too
3680 * Note that coredump() drops proc lock.
3681 */
3682 rv = coredump(td);
3683 switch (rv) {
3684 case 0:
3685 sig |= WCOREFLAG;
3686 coreinfo = " (core dumped)";
3687 break;
3688 case EFAULT:
3689 coreinfo = " (no core dump - bad address)";
3690 break;
3691 case EINVAL:
3692 coreinfo = " (no core dump - invalid argument)";
3693 break;
3694 case EFBIG:
3695 coreinfo = " (no core dump - too large)";
3696 break;
3697 default:
3698 coreinfo = " (no core dump - other error)";
3699 break;
3700 }
3701 if (logexit)
3702 log(LOG_INFO,
3703 "pid %d (%s), jid %d, uid %d: exited on "
3704 "signal %d%s\n", p->p_pid, p->p_comm,
3705 p->p_ucred->cr_prison->pr_id,
3706 td->td_ucred->cr_uid,
3707 sig &~ WCOREFLAG, coreinfo);
3708 } else
3709 PROC_UNLOCK(p);
3710 exit1(td, 0, sig);
3711 /* NOTREACHED */
3712 }
3713
3714 /*
3715 * Send queued SIGCHLD to parent when child process's state
3716 * is changed.
3717 */
3718 static void
sigparent(struct proc * p,int reason,int status)3719 sigparent(struct proc *p, int reason, int status)
3720 {
3721 PROC_LOCK_ASSERT(p, MA_OWNED);
3722 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3723
3724 if (p->p_ksi != NULL) {
3725 p->p_ksi->ksi_signo = SIGCHLD;
3726 p->p_ksi->ksi_code = reason;
3727 p->p_ksi->ksi_status = status;
3728 p->p_ksi->ksi_pid = p->p_pid;
3729 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
3730 if (KSI_ONQ(p->p_ksi))
3731 return;
3732 }
3733
3734 /*
3735 * Do not consume p_ksi if parent is zombie, since signal is
3736 * dropped immediately. Instead, keep it since it might be
3737 * useful for reaper.
3738 */
3739 if (p->p_pptr->p_state != PRS_ZOMBIE)
3740 pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
3741 }
3742
3743 static void
childproc_jobstate(struct proc * p,int reason,int sig)3744 childproc_jobstate(struct proc *p, int reason, int sig)
3745 {
3746 struct sigacts *ps;
3747
3748 PROC_LOCK_ASSERT(p, MA_OWNED);
3749 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
3750
3751 /*
3752 * Wake up parent sleeping in kern_wait(), also send
3753 * SIGCHLD to parent, but SIGCHLD does not guarantee
3754 * that parent will awake, because parent may masked
3755 * the signal.
3756 */
3757 p->p_pptr->p_flag |= P_STATCHILD;
3758 wakeup(p->p_pptr);
3759
3760 ps = p->p_pptr->p_sigacts;
3761 mtx_lock(&ps->ps_mtx);
3762 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
3763 mtx_unlock(&ps->ps_mtx);
3764 sigparent(p, reason, sig);
3765 } else
3766 mtx_unlock(&ps->ps_mtx);
3767 }
3768
3769 void
childproc_stopped(struct proc * p,int reason)3770 childproc_stopped(struct proc *p, int reason)
3771 {
3772
3773 childproc_jobstate(p, reason, p->p_xsig);
3774 }
3775
3776 void
childproc_continued(struct proc * p)3777 childproc_continued(struct proc *p)
3778 {
3779 PROC_LOCK_ASSERT(p, MA_OWNED);
3780 p->p_flag |= P_CONTINUED;
3781 p->p_xsig = SIGCONT;
3782 childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
3783 }
3784
3785 void
childproc_exited(struct proc * p)3786 childproc_exited(struct proc *p)
3787 {
3788 int reason, status;
3789
3790 if (WCOREDUMP(p->p_xsig)) {
3791 reason = CLD_DUMPED;
3792 status = WTERMSIG(p->p_xsig);
3793 } else if (WIFSIGNALED(p->p_xsig)) {
3794 reason = CLD_KILLED;
3795 status = WTERMSIG(p->p_xsig);
3796 } else {
3797 reason = CLD_EXITED;
3798 status = p->p_xexit;
3799 }
3800 /*
3801 * XXX avoid calling wakeup(p->p_pptr), the work is
3802 * done in exit1().
3803 */
3804 sigparent(p, reason, status);
3805 }
3806
3807 #define MAX_NUM_CORE_FILES 100000
3808 #ifndef NUM_CORE_FILES
3809 #define NUM_CORE_FILES 5
3810 #endif
3811 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES);
3812 static int num_cores = NUM_CORE_FILES;
3813
3814 static int
sysctl_debug_num_cores_check(SYSCTL_HANDLER_ARGS)3815 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
3816 {
3817 int error;
3818 int new_val;
3819
3820 new_val = num_cores;
3821 error = sysctl_handle_int(oidp, &new_val, 0, req);
3822 if (error != 0 || req->newptr == NULL)
3823 return (error);
3824 if (new_val > MAX_NUM_CORE_FILES)
3825 new_val = MAX_NUM_CORE_FILES;
3826 if (new_val < 0)
3827 new_val = 0;
3828 num_cores = new_val;
3829 return (0);
3830 }
3831 SYSCTL_PROC(_debug, OID_AUTO, ncores,
3832 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int),
3833 sysctl_debug_num_cores_check, "I",
3834 "Maximum number of generated process corefiles while using index format");
3835
3836 #define GZIP_SUFFIX ".gz"
3837 #define ZSTD_SUFFIX ".zst"
3838
3839 int compress_user_cores = 0;
3840
3841 static int
sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)3842 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)
3843 {
3844 int error, val;
3845
3846 val = compress_user_cores;
3847 error = sysctl_handle_int(oidp, &val, 0, req);
3848 if (error != 0 || req->newptr == NULL)
3849 return (error);
3850 if (val != 0 && !compressor_avail(val))
3851 return (EINVAL);
3852 compress_user_cores = val;
3853 return (error);
3854 }
3855 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores,
3856 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int),
3857 sysctl_compress_user_cores, "I",
3858 "Enable compression of user corefiles ("
3859 __XSTRING(COMPRESS_GZIP) " = gzip, "
3860 __XSTRING(COMPRESS_ZSTD) " = zstd)");
3861
3862 int compress_user_cores_level = 6;
3863 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN,
3864 &compress_user_cores_level, 0,
3865 "Corefile compression level");
3866
3867 /*
3868 * Protect the access to corefilename[] by allproc_lock.
3869 */
3870 #define corefilename_lock allproc_lock
3871
3872 static char corefilename[MAXPATHLEN] = {"%N.core"};
3873 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
3874
3875 static int
sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)3876 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
3877 {
3878 int error;
3879
3880 sx_xlock(&corefilename_lock);
3881 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
3882 req);
3883 sx_xunlock(&corefilename_lock);
3884
3885 return (error);
3886 }
3887 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
3888 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
3889 "Process corefile name format string");
3890
3891 static void
vnode_close_locked(struct thread * td,struct vnode * vp)3892 vnode_close_locked(struct thread *td, struct vnode *vp)
3893 {
3894
3895 VOP_UNLOCK(vp);
3896 vn_close(vp, FWRITE, td->td_ucred, td);
3897 }
3898
3899 /*
3900 * If the core format has a %I in it, then we need to check
3901 * for existing corefiles before defining a name.
3902 * To do this we iterate over 0..ncores to find a
3903 * non-existing core file name to use. If all core files are
3904 * already used we choose the oldest one.
3905 */
3906 static int
corefile_open_last(struct thread * td,char * name,int indexpos,int indexlen,int ncores,struct vnode ** vpp)3907 corefile_open_last(struct thread *td, char *name, int indexpos,
3908 int indexlen, int ncores, struct vnode **vpp)
3909 {
3910 struct vnode *oldvp, *nextvp, *vp;
3911 struct vattr vattr;
3912 struct nameidata nd;
3913 int error, i, flags, oflags, cmode;
3914 char ch;
3915 struct timespec lasttime;
3916
3917 nextvp = oldvp = NULL;
3918 cmode = S_IRUSR | S_IWUSR;
3919 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
3920 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
3921
3922 for (i = 0; i < ncores; i++) {
3923 flags = O_CREAT | FWRITE | O_NOFOLLOW;
3924
3925 ch = name[indexpos + indexlen];
3926 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen,
3927 i);
3928 name[indexpos + indexlen] = ch;
3929
3930 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name);
3931 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
3932 NULL);
3933 if (error != 0)
3934 break;
3935
3936 vp = nd.ni_vp;
3937 NDFREE_PNBUF(&nd);
3938 if ((flags & O_CREAT) == O_CREAT) {
3939 nextvp = vp;
3940 break;
3941 }
3942
3943 error = VOP_GETATTR(vp, &vattr, td->td_ucred);
3944 if (error != 0) {
3945 vnode_close_locked(td, vp);
3946 break;
3947 }
3948
3949 if (oldvp == NULL ||
3950 lasttime.tv_sec > vattr.va_mtime.tv_sec ||
3951 (lasttime.tv_sec == vattr.va_mtime.tv_sec &&
3952 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) {
3953 if (oldvp != NULL)
3954 vn_close(oldvp, FWRITE, td->td_ucred, td);
3955 oldvp = vp;
3956 VOP_UNLOCK(oldvp);
3957 lasttime = vattr.va_mtime;
3958 } else {
3959 vnode_close_locked(td, vp);
3960 }
3961 }
3962
3963 if (oldvp != NULL) {
3964 if (nextvp == NULL) {
3965 if ((td->td_proc->p_flag & P_SUGID) != 0) {
3966 error = EFAULT;
3967 vn_close(oldvp, FWRITE, td->td_ucred, td);
3968 } else {
3969 nextvp = oldvp;
3970 error = vn_lock(nextvp, LK_EXCLUSIVE);
3971 if (error != 0) {
3972 vn_close(nextvp, FWRITE, td->td_ucred,
3973 td);
3974 nextvp = NULL;
3975 }
3976 }
3977 } else {
3978 vn_close(oldvp, FWRITE, td->td_ucred, td);
3979 }
3980 }
3981 if (error != 0) {
3982 if (nextvp != NULL)
3983 vnode_close_locked(td, oldvp);
3984 } else {
3985 *vpp = nextvp;
3986 }
3987
3988 return (error);
3989 }
3990
3991 /*
3992 * corefile_open(comm, uid, pid, td, compress, vpp, namep)
3993 * Expand the name described in corefilename, using name, uid, and pid
3994 * and open/create core file.
3995 * corefilename is a printf-like string, with three format specifiers:
3996 * %N name of process ("name")
3997 * %P process id (pid)
3998 * %U user id (uid)
3999 * For example, "%N.core" is the default; they can be disabled completely
4000 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
4001 * This is controlled by the sysctl variable kern.corefile (see above).
4002 */
4003 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)4004 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
4005 int compress, int signum, struct vnode **vpp, char **namep)
4006 {
4007 struct sbuf sb;
4008 struct nameidata nd;
4009 const char *format;
4010 char *hostname, *name;
4011 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores;
4012
4013 hostname = NULL;
4014 format = corefilename;
4015 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
4016 indexlen = 0;
4017 indexpos = -1;
4018 ncores = num_cores;
4019 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
4020 sx_slock(&corefilename_lock);
4021 for (i = 0; format[i] != '\0'; i++) {
4022 switch (format[i]) {
4023 case '%': /* Format character */
4024 i++;
4025 switch (format[i]) {
4026 case '%':
4027 sbuf_putc(&sb, '%');
4028 break;
4029 case 'H': /* hostname */
4030 if (hostname == NULL) {
4031 hostname = malloc(MAXHOSTNAMELEN,
4032 M_TEMP, M_WAITOK);
4033 }
4034 getcredhostname(td->td_ucred, hostname,
4035 MAXHOSTNAMELEN);
4036 sbuf_cat(&sb, hostname);
4037 break;
4038 case 'I': /* autoincrementing index */
4039 if (indexpos != -1) {
4040 sbuf_printf(&sb, "%%I");
4041 break;
4042 }
4043
4044 indexpos = sbuf_len(&sb);
4045 sbuf_printf(&sb, "%u", ncores - 1);
4046 indexlen = sbuf_len(&sb) - indexpos;
4047 break;
4048 case 'N': /* process name */
4049 sbuf_printf(&sb, "%s", comm);
4050 break;
4051 case 'P': /* process id */
4052 sbuf_printf(&sb, "%u", pid);
4053 break;
4054 case 'S': /* signal number */
4055 sbuf_printf(&sb, "%i", signum);
4056 break;
4057 case 'U': /* user id */
4058 sbuf_printf(&sb, "%u", uid);
4059 break;
4060 default:
4061 log(LOG_ERR,
4062 "Unknown format character %c in "
4063 "corename `%s'\n", format[i], format);
4064 break;
4065 }
4066 break;
4067 default:
4068 sbuf_putc(&sb, format[i]);
4069 break;
4070 }
4071 }
4072 sx_sunlock(&corefilename_lock);
4073 free(hostname, M_TEMP);
4074 if (compress == COMPRESS_GZIP)
4075 sbuf_cat(&sb, GZIP_SUFFIX);
4076 else if (compress == COMPRESS_ZSTD)
4077 sbuf_cat(&sb, ZSTD_SUFFIX);
4078 if (sbuf_error(&sb) != 0) {
4079 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
4080 "long\n", (long)pid, comm, (u_long)uid);
4081 sbuf_delete(&sb);
4082 free(name, M_TEMP);
4083 return (ENOMEM);
4084 }
4085 sbuf_finish(&sb);
4086 sbuf_delete(&sb);
4087
4088 if (indexpos != -1) {
4089 error = corefile_open_last(td, name, indexpos, indexlen, ncores,
4090 vpp);
4091 if (error != 0) {
4092 log(LOG_ERR,
4093 "pid %d (%s), uid (%u): Path `%s' failed "
4094 "on initial open test, error = %d\n",
4095 pid, comm, uid, name, error);
4096 }
4097 } else {
4098 cmode = S_IRUSR | S_IWUSR;
4099 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
4100 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
4101 flags = O_CREAT | FWRITE | O_NOFOLLOW;
4102 if ((td->td_proc->p_flag & P_SUGID) != 0)
4103 flags |= O_EXCL;
4104
4105 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name);
4106 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
4107 NULL);
4108 if (error == 0) {
4109 *vpp = nd.ni_vp;
4110 NDFREE_PNBUF(&nd);
4111 }
4112 }
4113
4114 if (error != 0) {
4115 #ifdef AUDIT
4116 audit_proc_coredump(td, name, error);
4117 #endif
4118 free(name, M_TEMP);
4119 return (error);
4120 }
4121 *namep = name;
4122 return (0);
4123 }
4124
4125 /*
4126 * Dump a process' core. The main routine does some
4127 * policy checking, and creates the name of the coredump;
4128 * then it passes on a vnode and a size limit to the process-specific
4129 * coredump routine if there is one; if there _is not_ one, it returns
4130 * ENOSYS; otherwise it returns the error from the process-specific routine.
4131 */
4132
4133 static int
coredump(struct thread * td)4134 coredump(struct thread *td)
4135 {
4136 struct proc *p = td->td_proc;
4137 struct ucred *cred = td->td_ucred;
4138 struct vnode *vp;
4139 struct flock lf;
4140 struct vattr vattr;
4141 size_t fullpathsize;
4142 int error, error1, locked;
4143 char *name; /* name of corefile */
4144 void *rl_cookie;
4145 off_t limit;
4146 char *fullpath, *freepath = NULL;
4147 struct sbuf *sb;
4148
4149 PROC_LOCK_ASSERT(p, MA_OWNED);
4150 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
4151
4152 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
4153 (p->p_flag2 & P2_NOTRACE) != 0) {
4154 PROC_UNLOCK(p);
4155 return (EFAULT);
4156 }
4157
4158 /*
4159 * Note that the bulk of limit checking is done after
4160 * the corefile is created. The exception is if the limit
4161 * for corefiles is 0, in which case we don't bother
4162 * creating the corefile at all. This layout means that
4163 * a corefile is truncated instead of not being created,
4164 * if it is larger than the limit.
4165 */
4166 limit = (off_t)lim_cur(td, RLIMIT_CORE);
4167 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
4168 PROC_UNLOCK(p);
4169 return (EFBIG);
4170 }
4171 PROC_UNLOCK(p);
4172
4173 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
4174 compress_user_cores, p->p_sig, &vp, &name);
4175 if (error != 0)
4176 return (error);
4177
4178 /*
4179 * Don't dump to non-regular files or files with links.
4180 * Do not dump into system files. Effective user must own the corefile.
4181 */
4182 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
4183 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 ||
4184 vattr.va_uid != cred->cr_uid) {
4185 VOP_UNLOCK(vp);
4186 error = EFAULT;
4187 goto out;
4188 }
4189
4190 VOP_UNLOCK(vp);
4191
4192 /* Postpone other writers, including core dumps of other processes. */
4193 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
4194
4195 lf.l_whence = SEEK_SET;
4196 lf.l_start = 0;
4197 lf.l_len = 0;
4198 lf.l_type = F_WRLCK;
4199 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
4200
4201 VATTR_NULL(&vattr);
4202 vattr.va_size = 0;
4203 if (set_core_nodump_flag)
4204 vattr.va_flags = UF_NODUMP;
4205 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4206 VOP_SETATTR(vp, &vattr, cred);
4207 VOP_UNLOCK(vp);
4208 PROC_LOCK(p);
4209 p->p_acflag |= ACORE;
4210 PROC_UNLOCK(p);
4211
4212 if (p->p_sysent->sv_coredump != NULL) {
4213 error = p->p_sysent->sv_coredump(td, vp, limit, 0);
4214 } else {
4215 error = ENOSYS;
4216 }
4217
4218 if (locked) {
4219 lf.l_type = F_UNLCK;
4220 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
4221 }
4222 vn_rangelock_unlock(vp, rl_cookie);
4223
4224 /*
4225 * Notify the userland helper that a process triggered a core dump.
4226 * This allows the helper to run an automated debugging session.
4227 */
4228 if (error != 0 || coredump_devctl == 0)
4229 goto out;
4230 sb = sbuf_new_auto();
4231 if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0)
4232 goto out2;
4233 sbuf_cat(sb, "comm=\"");
4234 devctl_safe_quote_sb(sb, fullpath);
4235 free(freepath, M_TEMP);
4236 sbuf_cat(sb, "\" core=\"");
4237
4238 /*
4239 * We can't lookup core file vp directly. When we're replacing a core, and
4240 * other random times, we flush the name cache, so it will fail. Instead,
4241 * if the path of the core is relative, add the current dir in front if it.
4242 */
4243 if (name[0] != '/') {
4244 fullpathsize = MAXPATHLEN;
4245 freepath = malloc(fullpathsize, M_TEMP, M_WAITOK);
4246 if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) {
4247 free(freepath, M_TEMP);
4248 goto out2;
4249 }
4250 devctl_safe_quote_sb(sb, fullpath);
4251 free(freepath, M_TEMP);
4252 sbuf_putc(sb, '/');
4253 }
4254 devctl_safe_quote_sb(sb, name);
4255 sbuf_putc(sb, '"');
4256 if (sbuf_finish(sb) == 0)
4257 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb));
4258 out2:
4259 sbuf_delete(sb);
4260 out:
4261 error1 = vn_close(vp, FWRITE, cred, td);
4262 if (error == 0)
4263 error = error1;
4264 #ifdef AUDIT
4265 audit_proc_coredump(td, name, error);
4266 #endif
4267 free(name, M_TEMP);
4268 return (error);
4269 }
4270
4271 /*
4272 * Nonexistent system call-- signal process (may want to handle it). Flag
4273 * error in case process won't see signal immediately (blocked or ignored).
4274 */
4275 #ifndef _SYS_SYSPROTO_H_
4276 struct nosys_args {
4277 int dummy;
4278 };
4279 #endif
4280 /* ARGSUSED */
4281 int
nosys(struct thread * td,struct nosys_args * args)4282 nosys(struct thread *td, struct nosys_args *args)
4283 {
4284 struct proc *p;
4285
4286 p = td->td_proc;
4287
4288 if (SV_PROC_FLAG(p, SV_SIGSYS) != 0 && kern_signosys) {
4289 PROC_LOCK(p);
4290 tdsignal(td, SIGSYS);
4291 PROC_UNLOCK(p);
4292 }
4293 if (kern_lognosys == 1 || kern_lognosys == 3) {
4294 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
4295 td->td_sa.code);
4296 }
4297 if (kern_lognosys == 2 || kern_lognosys == 3 ||
4298 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
4299 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
4300 td->td_sa.code);
4301 }
4302 return (ENOSYS);
4303 }
4304
4305 /*
4306 * Send a SIGIO or SIGURG signal to a process or process group using stored
4307 * credentials rather than those of the current process.
4308 */
4309 void
pgsigio(struct sigio ** sigiop,int sig,int checkctty)4310 pgsigio(struct sigio **sigiop, int sig, int checkctty)
4311 {
4312 ksiginfo_t ksi;
4313 struct sigio *sigio;
4314
4315 ksiginfo_init(&ksi);
4316 ksi.ksi_signo = sig;
4317 ksi.ksi_code = SI_KERNEL;
4318
4319 SIGIO_LOCK();
4320 sigio = *sigiop;
4321 if (sigio == NULL) {
4322 SIGIO_UNLOCK();
4323 return;
4324 }
4325 if (sigio->sio_pgid > 0) {
4326 PROC_LOCK(sigio->sio_proc);
4327 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
4328 kern_psignal(sigio->sio_proc, sig);
4329 PROC_UNLOCK(sigio->sio_proc);
4330 } else if (sigio->sio_pgid < 0) {
4331 struct proc *p;
4332
4333 PGRP_LOCK(sigio->sio_pgrp);
4334 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
4335 PROC_LOCK(p);
4336 if (p->p_state == PRS_NORMAL &&
4337 CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
4338 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
4339 kern_psignal(p, sig);
4340 PROC_UNLOCK(p);
4341 }
4342 PGRP_UNLOCK(sigio->sio_pgrp);
4343 }
4344 SIGIO_UNLOCK();
4345 }
4346
4347 static int
filt_sigattach(struct knote * kn)4348 filt_sigattach(struct knote *kn)
4349 {
4350 struct proc *p = curproc;
4351
4352 kn->kn_ptr.p_proc = p;
4353 kn->kn_flags |= EV_CLEAR; /* automatically set */
4354
4355 knlist_add(p->p_klist, kn, 0);
4356
4357 return (0);
4358 }
4359
4360 static void
filt_sigdetach(struct knote * kn)4361 filt_sigdetach(struct knote *kn)
4362 {
4363 knlist_remove(kn->kn_knlist, kn, 0);
4364 }
4365
4366 /*
4367 * signal knotes are shared with proc knotes, so we apply a mask to
4368 * the hint in order to differentiate them from process hints. This
4369 * could be avoided by using a signal-specific knote list, but probably
4370 * isn't worth the trouble.
4371 */
4372 static int
filt_signal(struct knote * kn,long hint)4373 filt_signal(struct knote *kn, long hint)
4374 {
4375
4376 if (hint & NOTE_SIGNAL) {
4377 hint &= ~NOTE_SIGNAL;
4378
4379 if (kn->kn_id == hint)
4380 kn->kn_data++;
4381 }
4382 return (kn->kn_data != 0);
4383 }
4384
4385 struct sigacts *
sigacts_alloc(void)4386 sigacts_alloc(void)
4387 {
4388 struct sigacts *ps;
4389
4390 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
4391 refcount_init(&ps->ps_refcnt, 1);
4392 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
4393 return (ps);
4394 }
4395
4396 void
sigacts_free(struct sigacts * ps)4397 sigacts_free(struct sigacts *ps)
4398 {
4399
4400 if (refcount_release(&ps->ps_refcnt) == 0)
4401 return;
4402 mtx_destroy(&ps->ps_mtx);
4403 free(ps, M_SUBPROC);
4404 }
4405
4406 struct sigacts *
sigacts_hold(struct sigacts * ps)4407 sigacts_hold(struct sigacts *ps)
4408 {
4409
4410 refcount_acquire(&ps->ps_refcnt);
4411 return (ps);
4412 }
4413
4414 void
sigacts_copy(struct sigacts * dest,struct sigacts * src)4415 sigacts_copy(struct sigacts *dest, struct sigacts *src)
4416 {
4417
4418 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
4419 mtx_lock(&src->ps_mtx);
4420 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
4421 mtx_unlock(&src->ps_mtx);
4422 }
4423
4424 int
sigacts_shared(struct sigacts * ps)4425 sigacts_shared(struct sigacts *ps)
4426 {
4427
4428 return (ps->ps_refcnt > 1);
4429 }
4430
4431 void
sig_drop_caught(struct proc * p)4432 sig_drop_caught(struct proc *p)
4433 {
4434 int sig;
4435 struct sigacts *ps;
4436
4437 ps = p->p_sigacts;
4438 PROC_LOCK_ASSERT(p, MA_OWNED);
4439 mtx_assert(&ps->ps_mtx, MA_OWNED);
4440 SIG_FOREACH(sig, &ps->ps_sigcatch) {
4441 sigdflt(ps, sig);
4442 if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
4443 sigqueue_delete_proc(p, sig);
4444 }
4445 }
4446
4447 static void
sigfastblock_failed(struct thread * td,bool sendsig,bool write)4448 sigfastblock_failed(struct thread *td, bool sendsig, bool write)
4449 {
4450 ksiginfo_t ksi;
4451
4452 /*
4453 * Prevent further fetches and SIGSEGVs, allowing thread to
4454 * issue syscalls despite corruption.
4455 */
4456 sigfastblock_clear(td);
4457
4458 if (!sendsig)
4459 return;
4460 ksiginfo_init_trap(&ksi);
4461 ksi.ksi_signo = SIGSEGV;
4462 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR;
4463 ksi.ksi_addr = td->td_sigblock_ptr;
4464 trapsignal(td, &ksi);
4465 }
4466
4467 static bool
sigfastblock_fetch_sig(struct thread * td,bool sendsig,uint32_t * valp)4468 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp)
4469 {
4470 uint32_t res;
4471
4472 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4473 return (true);
4474 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) {
4475 sigfastblock_failed(td, sendsig, false);
4476 return (false);
4477 }
4478 *valp = res;
4479 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS;
4480 return (true);
4481 }
4482
4483 static void
sigfastblock_resched(struct thread * td,bool resched)4484 sigfastblock_resched(struct thread *td, bool resched)
4485 {
4486 struct proc *p;
4487
4488 if (resched) {
4489 p = td->td_proc;
4490 PROC_LOCK(p);
4491 reschedule_signals(p, td->td_sigmask, 0);
4492 PROC_UNLOCK(p);
4493 }
4494 ast_sched(td, TDA_SIG);
4495 }
4496
4497 int
sys_sigfastblock(struct thread * td,struct sigfastblock_args * uap)4498 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap)
4499 {
4500 struct proc *p;
4501 int error, res;
4502 uint32_t oldval;
4503
4504 error = 0;
4505 p = td->td_proc;
4506 switch (uap->cmd) {
4507 case SIGFASTBLOCK_SETPTR:
4508 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
4509 error = EBUSY;
4510 break;
4511 }
4512 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) {
4513 error = EINVAL;
4514 break;
4515 }
4516 td->td_pflags |= TDP_SIGFASTBLOCK;
4517 td->td_sigblock_ptr = uap->ptr;
4518 break;
4519
4520 case SIGFASTBLOCK_UNBLOCK:
4521 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4522 error = EINVAL;
4523 break;
4524 }
4525
4526 for (;;) {
4527 res = casueword32(td->td_sigblock_ptr,
4528 SIGFASTBLOCK_PEND, &oldval, 0);
4529 if (res == -1) {
4530 error = EFAULT;
4531 sigfastblock_failed(td, false, true);
4532 break;
4533 }
4534 if (res == 0)
4535 break;
4536 MPASS(res == 1);
4537 if (oldval != SIGFASTBLOCK_PEND) {
4538 error = EBUSY;
4539 break;
4540 }
4541 error = thread_check_susp(td, false);
4542 if (error != 0)
4543 break;
4544 }
4545 if (error != 0)
4546 break;
4547
4548 /*
4549 * td_sigblock_val is cleared there, but not on a
4550 * syscall exit. The end effect is that a single
4551 * interruptible sleep, while user sigblock word is
4552 * set, might return EINTR or ERESTART to usermode
4553 * without delivering signal. All further sleeps,
4554 * until userspace clears the word and does
4555 * sigfastblock(UNBLOCK), observe current word and no
4556 * longer get interrupted. It is slight
4557 * non-conformance, with alternative to have read the
4558 * sigblock word on each syscall entry.
4559 */
4560 td->td_sigblock_val = 0;
4561
4562 /*
4563 * Rely on normal ast mechanism to deliver pending
4564 * signals to current thread. But notify others about
4565 * fake unblock.
4566 */
4567 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1);
4568
4569 break;
4570
4571 case SIGFASTBLOCK_UNSETPTR:
4572 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
4573 error = EINVAL;
4574 break;
4575 }
4576 if (!sigfastblock_fetch_sig(td, false, &oldval)) {
4577 error = EFAULT;
4578 break;
4579 }
4580 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) {
4581 error = EBUSY;
4582 break;
4583 }
4584 sigfastblock_clear(td);
4585 break;
4586
4587 default:
4588 error = EINVAL;
4589 break;
4590 }
4591 return (error);
4592 }
4593
4594 void
sigfastblock_clear(struct thread * td)4595 sigfastblock_clear(struct thread *td)
4596 {
4597 bool resched;
4598
4599 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
4600 return;
4601 td->td_sigblock_val = 0;
4602 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 ||
4603 SIGPENDING(td);
4604 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING);
4605 sigfastblock_resched(td, resched);
4606 }
4607
4608 void
sigfastblock_fetch(struct thread * td)4609 sigfastblock_fetch(struct thread *td)
4610 {
4611 uint32_t val;
4612
4613 (void)sigfastblock_fetch_sig(td, true, &val);
4614 }
4615
4616 static void
sigfastblock_setpend1(struct thread * td)4617 sigfastblock_setpend1(struct thread *td)
4618 {
4619 int res;
4620 uint32_t oldval;
4621
4622 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0)
4623 return;
4624 res = fueword32((void *)td->td_sigblock_ptr, &oldval);
4625 if (res == -1) {
4626 sigfastblock_failed(td, true, false);
4627 return;
4628 }
4629 for (;;) {
4630 res = casueword32(td->td_sigblock_ptr, oldval, &oldval,
4631 oldval | SIGFASTBLOCK_PEND);
4632 if (res == -1) {
4633 sigfastblock_failed(td, true, true);
4634 return;
4635 }
4636 if (res == 0) {
4637 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS;
4638 td->td_pflags &= ~TDP_SIGFASTPENDING;
4639 break;
4640 }
4641 MPASS(res == 1);
4642 if (thread_check_susp(td, false) != 0)
4643 break;
4644 }
4645 }
4646
4647 static void
sigfastblock_setpend(struct thread * td,bool resched)4648 sigfastblock_setpend(struct thread *td, bool resched)
4649 {
4650 struct proc *p;
4651
4652 sigfastblock_setpend1(td);
4653 if (resched) {
4654 p = td->td_proc;
4655 PROC_LOCK(p);
4656 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
4657 PROC_UNLOCK(p);
4658 }
4659 }
4660