kern_sig.c revision 1.352
1 /* $NetBSD: kern_sig.c,v 1.352 2019/04/03 08:34:33 kamil Exp $ */ 2 3 /*- 4 * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1982, 1986, 1989, 1991, 1993 34 * The Regents of the University of California. All rights reserved. 35 * (c) UNIX System Laboratories, Inc. 36 * All or some portions of this file are derived from material licensed 37 * to the University of California by American Telephone and Telegraph 38 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 39 * the permission of UNIX System Laboratories, Inc. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 66 */ 67 68 /* 69 * Signal subsystem. 70 */ 71 72 #include <sys/cdefs.h> 73 __KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.352 2019/04/03 08:34:33 kamil Exp $"); 74 75 #include "opt_ptrace.h" 76 #include "opt_dtrace.h" 77 #include "opt_compat_sunos.h" 78 #include "opt_compat_netbsd.h" 79 #include "opt_compat_netbsd32.h" 80 #include "opt_pax.h" 81 82 #define SIGPROP /* include signal properties table */ 83 #include <sys/param.h> 84 #include <sys/signalvar.h> 85 #include <sys/proc.h> 86 #include <sys/ptrace.h> 87 #include <sys/systm.h> 88 #include <sys/wait.h> 89 #include <sys/ktrace.h> 90 #include <sys/syslog.h> 91 #include <sys/filedesc.h> 92 #include <sys/file.h> 93 #include <sys/pool.h> 94 #include <sys/ucontext.h> 95 #include <sys/exec.h> 96 #include <sys/kauth.h> 97 #include <sys/acct.h> 98 #include <sys/callout.h> 99 #include <sys/atomic.h> 100 #include <sys/cpu.h> 101 #include <sys/module.h> 102 #include <sys/sdt.h> 103 104 #ifdef PAX_SEGVGUARD 105 #include <sys/pax.h> 106 #endif /* PAX_SEGVGUARD */ 107 108 #include <uvm/uvm_extern.h> 109 110 #define SIGQUEUE_MAX 32 111 static pool_cache_t sigacts_cache __read_mostly; 112 static pool_cache_t ksiginfo_cache __read_mostly; 113 static callout_t proc_stop_ch __cacheline_aligned; 114 115 sigset_t contsigmask __cacheline_aligned; 116 sigset_t stopsigmask __cacheline_aligned; 117 static sigset_t vforksigmask __cacheline_aligned; 118 sigset_t sigcantmask __cacheline_aligned; 119 120 static void ksiginfo_exechook(struct proc *, void *); 121 static void proc_stop(struct proc *, int); 122 static void proc_stop_done(struct proc *, int); 123 static void proc_stop_callout(void *); 124 static int sigchecktrace(void); 125 static int sigpost(struct lwp *, sig_t, int, int); 126 static int sigput(sigpend_t *, struct proc *, ksiginfo_t *); 127 static int sigunwait(struct proc *, const ksiginfo_t *); 128 129 static void sigacts_poolpage_free(struct pool *, void *); 130 static void *sigacts_poolpage_alloc(struct pool *, int); 131 132 void (*sendsig_sigcontext_vec)(const struct ksiginfo *, const sigset_t *); 133 int (*coredump_vec)(struct lwp *, const char *) = 134 (int (*)(struct lwp *, const char *))enosys; 135 136 /* 137 * DTrace SDT provider definitions 138 */ 139 SDT_PROVIDER_DECLARE(proc); 140 SDT_PROBE_DEFINE3(proc, kernel, , signal__send, 141 "struct lwp *", /* target thread */ 142 "struct proc *", /* target process */ 143 "int"); /* signal */ 144 SDT_PROBE_DEFINE3(proc, kernel, , signal__discard, 145 "struct lwp *", /* target thread */ 146 "struct proc *", /* target process */ 147 "int"); /* signal */ 148 SDT_PROBE_DEFINE3(proc, kernel, , signal__handle, 149 "int", /* signal */ 150 "ksiginfo_t *", /* signal info */ 151 "void (*)(void)"); /* handler address */ 152 153 154 static struct pool_allocator sigactspool_allocator = { 155 .pa_alloc = sigacts_poolpage_alloc, 156 .pa_free = sigacts_poolpage_free 157 }; 158 159 #ifdef DEBUG 160 int kern_logsigexit = 1; 161 #else 162 int kern_logsigexit = 0; 163 #endif 164 165 static const char logcoredump[] = 166 "pid %d (%s), uid %d: exited on signal %d (core dumped)\n"; 167 static const char lognocoredump[] = 168 "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n"; 169 170 static kauth_listener_t signal_listener; 171 172 static int 173 signal_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 174 void *arg0, void *arg1, void *arg2, void *arg3) 175 { 176 struct proc *p; 177 int result, signum; 178 179 result = KAUTH_RESULT_DEFER; 180 p = arg0; 181 signum = (int)(unsigned long)arg1; 182 183 if (action != KAUTH_PROCESS_SIGNAL) 184 return result; 185 186 if (kauth_cred_uidmatch(cred, p->p_cred) || 187 (signum == SIGCONT && (curproc->p_session == p->p_session))) 188 result = KAUTH_RESULT_ALLOW; 189 190 return result; 191 } 192 193 static int 194 sigacts_ctor(void *arg __unused, void *obj, int flags __unused) 195 { 196 memset(obj, 0, sizeof(struct sigacts)); 197 return 0; 198 } 199 200 /* 201 * signal_init: 202 * 203 * Initialize global signal-related data structures. 204 */ 205 void 206 signal_init(void) 207 { 208 209 sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2; 210 211 sigacts_cache = pool_cache_init(sizeof(struct sigacts), 0, 0, 0, 212 "sigacts", sizeof(struct sigacts) > PAGE_SIZE ? 213 &sigactspool_allocator : NULL, IPL_NONE, sigacts_ctor, NULL, NULL); 214 ksiginfo_cache = pool_cache_init(sizeof(ksiginfo_t), 0, 0, 0, 215 "ksiginfo", NULL, IPL_VM, NULL, NULL, NULL); 216 217 exechook_establish(ksiginfo_exechook, NULL); 218 219 callout_init(&proc_stop_ch, CALLOUT_MPSAFE); 220 callout_setfunc(&proc_stop_ch, proc_stop_callout, NULL); 221 222 signal_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS, 223 signal_listener_cb, NULL); 224 } 225 226 /* 227 * sigacts_poolpage_alloc: 228 * 229 * Allocate a page for the sigacts memory pool. 230 */ 231 static void * 232 sigacts_poolpage_alloc(struct pool *pp, int flags) 233 { 234 235 return (void *)uvm_km_alloc(kernel_map, 236 PAGE_SIZE * 2, PAGE_SIZE * 2, 237 ((flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK) 238 | UVM_KMF_WIRED); 239 } 240 241 /* 242 * sigacts_poolpage_free: 243 * 244 * Free a page on behalf of the sigacts memory pool. 245 */ 246 static void 247 sigacts_poolpage_free(struct pool *pp, void *v) 248 { 249 250 uvm_km_free(kernel_map, (vaddr_t)v, PAGE_SIZE * 2, UVM_KMF_WIRED); 251 } 252 253 /* 254 * sigactsinit: 255 * 256 * Create an initial sigacts structure, using the same signal state 257 * as of specified process. If 'share' is set, share the sigacts by 258 * holding a reference, otherwise just copy it from parent. 259 */ 260 struct sigacts * 261 sigactsinit(struct proc *pp, int share) 262 { 263 struct sigacts *ps = pp->p_sigacts, *ps2; 264 265 if (__predict_false(share)) { 266 atomic_inc_uint(&ps->sa_refcnt); 267 return ps; 268 } 269 ps2 = pool_cache_get(sigacts_cache, PR_WAITOK); 270 mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 271 ps2->sa_refcnt = 1; 272 273 mutex_enter(&ps->sa_mutex); 274 memcpy(ps2->sa_sigdesc, ps->sa_sigdesc, sizeof(ps2->sa_sigdesc)); 275 mutex_exit(&ps->sa_mutex); 276 return ps2; 277 } 278 279 /* 280 * sigactsunshare: 281 * 282 * Make this process not share its sigacts, maintaining all signal state. 283 */ 284 void 285 sigactsunshare(struct proc *p) 286 { 287 struct sigacts *ps, *oldps = p->p_sigacts; 288 289 if (__predict_true(oldps->sa_refcnt == 1)) 290 return; 291 292 ps = pool_cache_get(sigacts_cache, PR_WAITOK); 293 mutex_init(&ps->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 294 memcpy(ps->sa_sigdesc, oldps->sa_sigdesc, sizeof(ps->sa_sigdesc)); 295 ps->sa_refcnt = 1; 296 297 p->p_sigacts = ps; 298 sigactsfree(oldps); 299 } 300 301 /* 302 * sigactsfree; 303 * 304 * Release a sigacts structure. 305 */ 306 void 307 sigactsfree(struct sigacts *ps) 308 { 309 310 if (atomic_dec_uint_nv(&ps->sa_refcnt) == 0) { 311 mutex_destroy(&ps->sa_mutex); 312 pool_cache_put(sigacts_cache, ps); 313 } 314 } 315 316 /* 317 * siginit: 318 * 319 * Initialize signal state for process 0; set to ignore signals that 320 * are ignored by default and disable the signal stack. Locking not 321 * required as the system is still cold. 322 */ 323 void 324 siginit(struct proc *p) 325 { 326 struct lwp *l; 327 struct sigacts *ps; 328 int signo, prop; 329 330 ps = p->p_sigacts; 331 sigemptyset(&contsigmask); 332 sigemptyset(&stopsigmask); 333 sigemptyset(&vforksigmask); 334 sigemptyset(&sigcantmask); 335 for (signo = 1; signo < NSIG; signo++) { 336 prop = sigprop[signo]; 337 if (prop & SA_CONT) 338 sigaddset(&contsigmask, signo); 339 if (prop & SA_STOP) 340 sigaddset(&stopsigmask, signo); 341 if (prop & SA_STOP && signo != SIGSTOP) 342 sigaddset(&vforksigmask, signo); 343 if (prop & SA_CANTMASK) 344 sigaddset(&sigcantmask, signo); 345 if (prop & SA_IGNORE && signo != SIGCONT) 346 sigaddset(&p->p_sigctx.ps_sigignore, signo); 347 sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); 348 SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; 349 } 350 sigemptyset(&p->p_sigctx.ps_sigcatch); 351 p->p_sflag &= ~PS_NOCLDSTOP; 352 353 ksiginfo_queue_init(&p->p_sigpend.sp_info); 354 sigemptyset(&p->p_sigpend.sp_set); 355 356 /* 357 * Reset per LWP state. 358 */ 359 l = LIST_FIRST(&p->p_lwps); 360 l->l_sigwaited = NULL; 361 l->l_sigstk = SS_INIT; 362 ksiginfo_queue_init(&l->l_sigpend.sp_info); 363 sigemptyset(&l->l_sigpend.sp_set); 364 365 /* One reference. */ 366 ps->sa_refcnt = 1; 367 } 368 369 /* 370 * execsigs: 371 * 372 * Reset signals for an exec of the specified process. 373 */ 374 void 375 execsigs(struct proc *p) 376 { 377 struct sigacts *ps; 378 struct lwp *l; 379 int signo, prop; 380 sigset_t tset; 381 ksiginfoq_t kq; 382 383 KASSERT(p->p_nlwps == 1); 384 385 sigactsunshare(p); 386 ps = p->p_sigacts; 387 388 /* 389 * Reset caught signals. Held signals remain held through 390 * l->l_sigmask (unless they were caught, and are now ignored 391 * by default). 392 * 393 * No need to lock yet, the process has only one LWP and 394 * at this point the sigacts are private to the process. 395 */ 396 sigemptyset(&tset); 397 for (signo = 1; signo < NSIG; signo++) { 398 if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) { 399 prop = sigprop[signo]; 400 if (prop & SA_IGNORE) { 401 if ((prop & SA_CONT) == 0) 402 sigaddset(&p->p_sigctx.ps_sigignore, 403 signo); 404 sigaddset(&tset, signo); 405 } 406 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 407 } 408 sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); 409 SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; 410 } 411 ksiginfo_queue_init(&kq); 412 413 mutex_enter(p->p_lock); 414 sigclearall(p, &tset, &kq); 415 sigemptyset(&p->p_sigctx.ps_sigcatch); 416 417 /* 418 * Reset no zombies if child dies flag as Solaris does. 419 */ 420 p->p_flag &= ~(PK_NOCLDWAIT | PK_CLDSIGIGN); 421 if (SIGACTION_PS(ps, SIGCHLD).sa_handler == SIG_IGN) 422 SIGACTION_PS(ps, SIGCHLD).sa_handler = SIG_DFL; 423 424 /* 425 * Reset per-LWP state. 426 */ 427 l = LIST_FIRST(&p->p_lwps); 428 l->l_sigwaited = NULL; 429 l->l_sigstk = SS_INIT; 430 ksiginfo_queue_init(&l->l_sigpend.sp_info); 431 sigemptyset(&l->l_sigpend.sp_set); 432 mutex_exit(p->p_lock); 433 434 ksiginfo_queue_drain(&kq); 435 } 436 437 /* 438 * ksiginfo_exechook: 439 * 440 * Free all pending ksiginfo entries from a process on exec. 441 * Additionally, drain any unused ksiginfo structures in the 442 * system back to the pool. 443 * 444 * XXX This should not be a hook, every process has signals. 445 */ 446 static void 447 ksiginfo_exechook(struct proc *p, void *v) 448 { 449 ksiginfoq_t kq; 450 451 ksiginfo_queue_init(&kq); 452 453 mutex_enter(p->p_lock); 454 sigclearall(p, NULL, &kq); 455 mutex_exit(p->p_lock); 456 457 ksiginfo_queue_drain(&kq); 458 } 459 460 /* 461 * ksiginfo_alloc: 462 * 463 * Allocate a new ksiginfo structure from the pool, and optionally copy 464 * an existing one. If the existing ksiginfo_t is from the pool, and 465 * has not been queued somewhere, then just return it. Additionally, 466 * if the existing ksiginfo_t does not contain any information beyond 467 * the signal number, then just return it. 468 */ 469 ksiginfo_t * 470 ksiginfo_alloc(struct proc *p, ksiginfo_t *ok, int flags) 471 { 472 ksiginfo_t *kp; 473 474 if (ok != NULL) { 475 if ((ok->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) == 476 KSI_FROMPOOL) 477 return ok; 478 if (KSI_EMPTY_P(ok)) 479 return ok; 480 } 481 482 kp = pool_cache_get(ksiginfo_cache, flags); 483 if (kp == NULL) { 484 #ifdef DIAGNOSTIC 485 printf("Out of memory allocating ksiginfo for pid %d\n", 486 p->p_pid); 487 #endif 488 return NULL; 489 } 490 491 if (ok != NULL) { 492 memcpy(kp, ok, sizeof(*kp)); 493 kp->ksi_flags &= ~KSI_QUEUED; 494 } else 495 KSI_INIT_EMPTY(kp); 496 497 kp->ksi_flags |= KSI_FROMPOOL; 498 499 return kp; 500 } 501 502 /* 503 * ksiginfo_free: 504 * 505 * If the given ksiginfo_t is from the pool and has not been queued, 506 * then free it. 507 */ 508 void 509 ksiginfo_free(ksiginfo_t *kp) 510 { 511 512 if ((kp->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) != KSI_FROMPOOL) 513 return; 514 pool_cache_put(ksiginfo_cache, kp); 515 } 516 517 /* 518 * ksiginfo_queue_drain: 519 * 520 * Drain a non-empty ksiginfo_t queue. 521 */ 522 void 523 ksiginfo_queue_drain0(ksiginfoq_t *kq) 524 { 525 ksiginfo_t *ksi; 526 527 KASSERT(!TAILQ_EMPTY(kq)); 528 529 while (!TAILQ_EMPTY(kq)) { 530 ksi = TAILQ_FIRST(kq); 531 TAILQ_REMOVE(kq, ksi, ksi_list); 532 pool_cache_put(ksiginfo_cache, ksi); 533 } 534 } 535 536 static int 537 siggetinfo(sigpend_t *sp, ksiginfo_t *out, int signo) 538 { 539 ksiginfo_t *ksi, *nksi; 540 541 if (sp == NULL) 542 goto out; 543 544 /* Find siginfo and copy it out. */ 545 int count = 0; 546 TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, nksi) { 547 if (ksi->ksi_signo != signo) 548 continue; 549 if (count++ > 0) /* Only remove the first, count all of them */ 550 continue; 551 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 552 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 553 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 554 ksi->ksi_flags &= ~KSI_QUEUED; 555 if (out != NULL) { 556 memcpy(out, ksi, sizeof(*out)); 557 out->ksi_flags &= ~(KSI_FROMPOOL | KSI_QUEUED); 558 } 559 ksiginfo_free(ksi); 560 } 561 if (count) 562 return count; 563 564 out: 565 /* If there is no siginfo, then manufacture it. */ 566 if (out != NULL) { 567 KSI_INIT(out); 568 out->ksi_info._signo = signo; 569 out->ksi_info._code = SI_NOINFO; 570 } 571 return 0; 572 } 573 574 /* 575 * sigget: 576 * 577 * Fetch the first pending signal from a set. Optionally, also fetch 578 * or manufacture a ksiginfo element. Returns the number of the first 579 * pending signal, or zero. 580 */ 581 int 582 sigget(sigpend_t *sp, ksiginfo_t *out, int signo, const sigset_t *mask) 583 { 584 sigset_t tset; 585 int count; 586 587 /* If there's no pending set, the signal is from the debugger. */ 588 if (sp == NULL) 589 goto out; 590 591 /* Construct mask from signo, and 'mask'. */ 592 if (signo == 0) { 593 if (mask != NULL) { 594 tset = *mask; 595 __sigandset(&sp->sp_set, &tset); 596 } else 597 tset = sp->sp_set; 598 599 /* If there are no signals pending - return. */ 600 if ((signo = firstsig(&tset)) == 0) 601 goto out; 602 } else { 603 KASSERT(sigismember(&sp->sp_set, signo)); 604 } 605 606 sigdelset(&sp->sp_set, signo); 607 out: 608 count = siggetinfo(sp, out, signo); 609 if (count > 1) 610 sigaddset(&sp->sp_set, signo); 611 return signo; 612 } 613 614 /* 615 * sigput: 616 * 617 * Append a new ksiginfo element to the list of pending ksiginfo's. 618 */ 619 static int 620 sigput(sigpend_t *sp, struct proc *p, ksiginfo_t *ksi) 621 { 622 ksiginfo_t *kp; 623 624 KASSERT(mutex_owned(p->p_lock)); 625 KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); 626 627 sigaddset(&sp->sp_set, ksi->ksi_signo); 628 629 /* 630 * If there is no siginfo, we are done. 631 */ 632 if (KSI_EMPTY_P(ksi)) 633 return 0; 634 635 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 636 637 size_t count = 0; 638 TAILQ_FOREACH(kp, &sp->sp_info, ksi_list) { 639 count++; 640 if (ksi->ksi_signo >= SIGRTMIN && ksi->ksi_signo <= SIGRTMAX) 641 continue; 642 if (kp->ksi_signo == ksi->ksi_signo) { 643 KSI_COPY(ksi, kp); 644 kp->ksi_flags |= KSI_QUEUED; 645 return 0; 646 } 647 } 648 649 if (count >= SIGQUEUE_MAX) { 650 #ifdef DIAGNOSTIC 651 printf("%s(%d): Signal queue is full signal=%d\n", 652 p->p_comm, p->p_pid, ksi->ksi_signo); 653 #endif 654 return EAGAIN; 655 } 656 ksi->ksi_flags |= KSI_QUEUED; 657 TAILQ_INSERT_TAIL(&sp->sp_info, ksi, ksi_list); 658 659 return 0; 660 } 661 662 /* 663 * sigclear: 664 * 665 * Clear all pending signals in the specified set. 666 */ 667 void 668 sigclear(sigpend_t *sp, const sigset_t *mask, ksiginfoq_t *kq) 669 { 670 ksiginfo_t *ksi, *next; 671 672 if (mask == NULL) 673 sigemptyset(&sp->sp_set); 674 else 675 sigminusset(mask, &sp->sp_set); 676 677 TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, next) { 678 if (mask == NULL || sigismember(mask, ksi->ksi_signo)) { 679 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 680 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 681 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 682 TAILQ_INSERT_TAIL(kq, ksi, ksi_list); 683 } 684 } 685 } 686 687 /* 688 * sigclearall: 689 * 690 * Clear all pending signals in the specified set from a process and 691 * its LWPs. 692 */ 693 void 694 sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq) 695 { 696 struct lwp *l; 697 698 KASSERT(mutex_owned(p->p_lock)); 699 700 sigclear(&p->p_sigpend, mask, kq); 701 702 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 703 sigclear(&l->l_sigpend, mask, kq); 704 } 705 } 706 707 /* 708 * sigispending: 709 * 710 * Return the first signal number if there are pending signals for the 711 * current LWP. May be called unlocked provided that LW_PENDSIG is set, 712 * and that the signal has been posted to the appopriate queue before 713 * LW_PENDSIG is set. 714 */ 715 int 716 sigispending(struct lwp *l, int signo) 717 { 718 struct proc *p = l->l_proc; 719 sigset_t tset; 720 721 membar_consumer(); 722 723 tset = l->l_sigpend.sp_set; 724 sigplusset(&p->p_sigpend.sp_set, &tset); 725 sigminusset(&p->p_sigctx.ps_sigignore, &tset); 726 sigminusset(&l->l_sigmask, &tset); 727 728 if (signo == 0) { 729 return firstsig(&tset); 730 } 731 return sigismember(&tset, signo) ? signo : 0; 732 } 733 734 void 735 getucontext(struct lwp *l, ucontext_t *ucp) 736 { 737 struct proc *p = l->l_proc; 738 739 KASSERT(mutex_owned(p->p_lock)); 740 741 ucp->uc_flags = 0; 742 ucp->uc_link = l->l_ctxlink; 743 ucp->uc_sigmask = l->l_sigmask; 744 ucp->uc_flags |= _UC_SIGMASK; 745 746 /* 747 * The (unsupplied) definition of the `current execution stack' 748 * in the System V Interface Definition appears to allow returning 749 * the main context stack. 750 */ 751 if ((l->l_sigstk.ss_flags & SS_ONSTACK) == 0) { 752 ucp->uc_stack.ss_sp = (void *)l->l_proc->p_stackbase; 753 ucp->uc_stack.ss_size = ctob(l->l_proc->p_vmspace->vm_ssize); 754 ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */ 755 } else { 756 /* Simply copy alternate signal execution stack. */ 757 ucp->uc_stack = l->l_sigstk; 758 } 759 ucp->uc_flags |= _UC_STACK; 760 mutex_exit(p->p_lock); 761 cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags); 762 mutex_enter(p->p_lock); 763 } 764 765 int 766 setucontext(struct lwp *l, const ucontext_t *ucp) 767 { 768 struct proc *p = l->l_proc; 769 int error; 770 771 KASSERT(mutex_owned(p->p_lock)); 772 773 if ((ucp->uc_flags & _UC_SIGMASK) != 0) { 774 error = sigprocmask1(l, SIG_SETMASK, &ucp->uc_sigmask, NULL); 775 if (error != 0) 776 return error; 777 } 778 779 mutex_exit(p->p_lock); 780 error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags); 781 mutex_enter(p->p_lock); 782 if (error != 0) 783 return (error); 784 785 l->l_ctxlink = ucp->uc_link; 786 787 /* 788 * If there was stack information, update whether or not we are 789 * still running on an alternate signal stack. 790 */ 791 if ((ucp->uc_flags & _UC_STACK) != 0) { 792 if (ucp->uc_stack.ss_flags & SS_ONSTACK) 793 l->l_sigstk.ss_flags |= SS_ONSTACK; 794 else 795 l->l_sigstk.ss_flags &= ~SS_ONSTACK; 796 } 797 798 return 0; 799 } 800 801 /* 802 * killpg1: common code for kill process group/broadcast kill. 803 */ 804 int 805 killpg1(struct lwp *l, ksiginfo_t *ksi, int pgid, int all) 806 { 807 struct proc *p, *cp; 808 kauth_cred_t pc; 809 struct pgrp *pgrp; 810 int nfound; 811 int signo = ksi->ksi_signo; 812 813 cp = l->l_proc; 814 pc = l->l_cred; 815 nfound = 0; 816 817 mutex_enter(proc_lock); 818 if (all) { 819 /* 820 * Broadcast. 821 */ 822 PROCLIST_FOREACH(p, &allproc) { 823 if (p->p_pid <= 1 || p == cp || 824 (p->p_flag & PK_SYSTEM) != 0) 825 continue; 826 mutex_enter(p->p_lock); 827 if (kauth_authorize_process(pc, 828 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signo), NULL, 829 NULL) == 0) { 830 nfound++; 831 if (signo) 832 kpsignal2(p, ksi); 833 } 834 mutex_exit(p->p_lock); 835 } 836 } else { 837 if (pgid == 0) 838 /* Zero pgid means send to my process group. */ 839 pgrp = cp->p_pgrp; 840 else { 841 pgrp = pgrp_find(pgid); 842 if (pgrp == NULL) 843 goto out; 844 } 845 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 846 if (p->p_pid <= 1 || p->p_flag & PK_SYSTEM) 847 continue; 848 mutex_enter(p->p_lock); 849 if (kauth_authorize_process(pc, KAUTH_PROCESS_SIGNAL, 850 p, KAUTH_ARG(signo), NULL, NULL) == 0) { 851 nfound++; 852 if (signo && P_ZOMBIE(p) == 0) 853 kpsignal2(p, ksi); 854 } 855 mutex_exit(p->p_lock); 856 } 857 } 858 out: 859 mutex_exit(proc_lock); 860 return nfound ? 0 : ESRCH; 861 } 862 863 /* 864 * Send a signal to a process group. If checktty is set, limit to members 865 * which have a controlling terminal. 866 */ 867 void 868 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 869 { 870 ksiginfo_t ksi; 871 872 KASSERT(!cpu_intr_p()); 873 KASSERT(mutex_owned(proc_lock)); 874 875 KSI_INIT_EMPTY(&ksi); 876 ksi.ksi_signo = sig; 877 kpgsignal(pgrp, &ksi, NULL, checkctty); 878 } 879 880 void 881 kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty) 882 { 883 struct proc *p; 884 885 KASSERT(!cpu_intr_p()); 886 KASSERT(mutex_owned(proc_lock)); 887 KASSERT(pgrp != NULL); 888 889 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) 890 if (checkctty == 0 || p->p_lflag & PL_CONTROLT) 891 kpsignal(p, ksi, data); 892 } 893 894 /* 895 * Send a signal caused by a trap to the current LWP. If it will be caught 896 * immediately, deliver it with correct code. Otherwise, post it normally. 897 */ 898 void 899 trapsignal(struct lwp *l, ksiginfo_t *ksi) 900 { 901 struct proc *p; 902 struct sigacts *ps; 903 int signo = ksi->ksi_signo; 904 sigset_t *mask; 905 906 KASSERT(KSI_TRAP_P(ksi)); 907 908 ksi->ksi_lid = l->l_lid; 909 p = l->l_proc; 910 911 KASSERT(!cpu_intr_p()); 912 mutex_enter(proc_lock); 913 mutex_enter(p->p_lock); 914 915 if (ISSET(p->p_slflag, PSL_TRACED) && 916 !(p->p_pptr == p->p_opptr && ISSET(p->p_lflag, PL_PPWAIT))) { 917 p->p_xsig = signo; 918 p->p_sigctx.ps_faked = true; // XXX 919 p->p_sigctx.ps_info._signo = signo; 920 p->p_sigctx.ps_info._code = ksi->ksi_code; 921 sigswitch(0, signo, false); 922 // XXX ktrpoint(KTR_PSIG) 923 mutex_exit(p->p_lock); 924 return; 925 } 926 927 mask = &l->l_sigmask; 928 ps = p->p_sigacts; 929 930 const bool caught = sigismember(&p->p_sigctx.ps_sigcatch, signo); 931 const bool masked = sigismember(mask, signo); 932 if (caught && !masked) { 933 mutex_exit(proc_lock); 934 l->l_ru.ru_nsignals++; 935 kpsendsig(l, ksi, mask); 936 mutex_exit(p->p_lock); 937 if (ktrpoint(KTR_PSIG)) { 938 if (p->p_emul->e_ktrpsig) 939 p->p_emul->e_ktrpsig(signo, 940 SIGACTION_PS(ps, signo).sa_handler, 941 mask, ksi); 942 else 943 ktrpsig(signo, 944 SIGACTION_PS(ps, signo).sa_handler, 945 mask, ksi); 946 } 947 return; 948 } 949 950 /* 951 * If the signal is masked or ignored, then unmask it and 952 * reset it to the default action so that the process or 953 * its tracer will be notified. 954 */ 955 const bool ignored = SIGACTION_PS(ps, signo).sa_handler == SIG_IGN; 956 if (masked || ignored) { 957 mutex_enter(&ps->sa_mutex); 958 sigdelset(mask, signo); 959 sigdelset(&p->p_sigctx.ps_sigcatch, signo); 960 sigdelset(&p->p_sigctx.ps_sigignore, signo); 961 sigdelset(&SIGACTION_PS(ps, signo).sa_mask, signo); 962 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 963 mutex_exit(&ps->sa_mutex); 964 } 965 966 kpsignal2(p, ksi); 967 mutex_exit(p->p_lock); 968 mutex_exit(proc_lock); 969 } 970 971 /* 972 * Fill in signal information and signal the parent for a child status change. 973 */ 974 void 975 child_psignal(struct proc *p, int mask) 976 { 977 ksiginfo_t ksi; 978 struct proc *q; 979 int xsig; 980 981 KASSERT(mutex_owned(proc_lock)); 982 KASSERT(mutex_owned(p->p_lock)); 983 984 xsig = p->p_xsig; 985 986 KSI_INIT(&ksi); 987 ksi.ksi_signo = SIGCHLD; 988 ksi.ksi_code = (xsig == SIGCONT ? CLD_CONTINUED : CLD_STOPPED); 989 ksi.ksi_pid = p->p_pid; 990 ksi.ksi_uid = kauth_cred_geteuid(p->p_cred); 991 ksi.ksi_status = xsig; 992 ksi.ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 993 ksi.ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 994 995 q = p->p_pptr; 996 997 mutex_exit(p->p_lock); 998 mutex_enter(q->p_lock); 999 1000 if ((q->p_sflag & mask) == 0) 1001 kpsignal2(q, &ksi); 1002 1003 mutex_exit(q->p_lock); 1004 mutex_enter(p->p_lock); 1005 } 1006 1007 void 1008 psignal(struct proc *p, int signo) 1009 { 1010 ksiginfo_t ksi; 1011 1012 KASSERT(!cpu_intr_p()); 1013 KASSERT(mutex_owned(proc_lock)); 1014 1015 KSI_INIT_EMPTY(&ksi); 1016 ksi.ksi_signo = signo; 1017 mutex_enter(p->p_lock); 1018 kpsignal2(p, &ksi); 1019 mutex_exit(p->p_lock); 1020 } 1021 1022 void 1023 kpsignal(struct proc *p, ksiginfo_t *ksi, void *data) 1024 { 1025 fdfile_t *ff; 1026 file_t *fp; 1027 fdtab_t *dt; 1028 1029 KASSERT(!cpu_intr_p()); 1030 KASSERT(mutex_owned(proc_lock)); 1031 1032 if ((p->p_sflag & PS_WEXIT) == 0 && data) { 1033 size_t fd; 1034 filedesc_t *fdp = p->p_fd; 1035 1036 /* XXXSMP locking */ 1037 ksi->ksi_fd = -1; 1038 dt = fdp->fd_dt; 1039 for (fd = 0; fd < dt->dt_nfiles; fd++) { 1040 if ((ff = dt->dt_ff[fd]) == NULL) 1041 continue; 1042 if ((fp = ff->ff_file) == NULL) 1043 continue; 1044 if (fp->f_data == data) { 1045 ksi->ksi_fd = fd; 1046 break; 1047 } 1048 } 1049 } 1050 mutex_enter(p->p_lock); 1051 kpsignal2(p, ksi); 1052 mutex_exit(p->p_lock); 1053 } 1054 1055 /* 1056 * sigismasked: 1057 * 1058 * Returns true if signal is ignored or masked for the specified LWP. 1059 */ 1060 int 1061 sigismasked(struct lwp *l, int sig) 1062 { 1063 struct proc *p = l->l_proc; 1064 1065 return sigismember(&p->p_sigctx.ps_sigignore, sig) || 1066 sigismember(&l->l_sigmask, sig); 1067 } 1068 1069 /* 1070 * sigpost: 1071 * 1072 * Post a pending signal to an LWP. Returns non-zero if the LWP may 1073 * be able to take the signal. 1074 */ 1075 static int 1076 sigpost(struct lwp *l, sig_t action, int prop, int sig) 1077 { 1078 int rv, masked; 1079 struct proc *p = l->l_proc; 1080 1081 KASSERT(mutex_owned(p->p_lock)); 1082 1083 /* 1084 * If the LWP is on the way out, sigclear() will be busy draining all 1085 * pending signals. Don't give it more. 1086 */ 1087 if (l->l_refcnt == 0) 1088 return 0; 1089 1090 SDT_PROBE(proc, kernel, , signal__send, l, p, sig, 0, 0); 1091 1092 /* 1093 * Have the LWP check for signals. This ensures that even if no LWP 1094 * is found to take the signal immediately, it should be taken soon. 1095 */ 1096 lwp_lock(l); 1097 l->l_flag |= LW_PENDSIG; 1098 1099 /* 1100 * SIGCONT can be masked, but if LWP is stopped, it needs restart. 1101 * Note: SIGKILL and SIGSTOP cannot be masked. 1102 */ 1103 masked = sigismember(&l->l_sigmask, sig); 1104 if (masked && ((prop & SA_CONT) == 0 || l->l_stat != LSSTOP)) { 1105 lwp_unlock(l); 1106 return 0; 1107 } 1108 1109 /* 1110 * If killing the process, make it run fast. 1111 */ 1112 if (__predict_false((prop & SA_KILL) != 0) && 1113 action == SIG_DFL && l->l_priority < MAXPRI_USER) { 1114 KASSERT(l->l_class == SCHED_OTHER); 1115 lwp_changepri(l, MAXPRI_USER); 1116 } 1117 1118 /* 1119 * If the LWP is running or on a run queue, then we win. If it's 1120 * sleeping interruptably, wake it and make it take the signal. If 1121 * the sleep isn't interruptable, then the chances are it will get 1122 * to see the signal soon anyhow. If suspended, it can't take the 1123 * signal right now. If it's LWP private or for all LWPs, save it 1124 * for later; otherwise punt. 1125 */ 1126 rv = 0; 1127 1128 switch (l->l_stat) { 1129 case LSRUN: 1130 case LSONPROC: 1131 lwp_need_userret(l); 1132 rv = 1; 1133 break; 1134 1135 case LSSLEEP: 1136 if ((l->l_flag & LW_SINTR) != 0) { 1137 /* setrunnable() will release the lock. */ 1138 setrunnable(l); 1139 return 1; 1140 } 1141 break; 1142 1143 case LSSUSPENDED: 1144 if ((prop & SA_KILL) != 0 && (l->l_flag & LW_WCORE) != 0) { 1145 /* lwp_continue() will release the lock. */ 1146 lwp_continue(l); 1147 return 1; 1148 } 1149 break; 1150 1151 case LSSTOP: 1152 if ((prop & SA_STOP) != 0) 1153 break; 1154 1155 /* 1156 * If the LWP is stopped and we are sending a continue 1157 * signal, then start it again. 1158 */ 1159 if ((prop & SA_CONT) != 0) { 1160 if (l->l_wchan != NULL) { 1161 l->l_stat = LSSLEEP; 1162 p->p_nrlwps++; 1163 rv = 1; 1164 break; 1165 } 1166 /* setrunnable() will release the lock. */ 1167 setrunnable(l); 1168 return 1; 1169 } else if (l->l_wchan == NULL || (l->l_flag & LW_SINTR) != 0) { 1170 /* setrunnable() will release the lock. */ 1171 setrunnable(l); 1172 return 1; 1173 } 1174 break; 1175 1176 default: 1177 break; 1178 } 1179 1180 lwp_unlock(l); 1181 return rv; 1182 } 1183 1184 /* 1185 * Notify an LWP that it has a pending signal. 1186 */ 1187 void 1188 signotify(struct lwp *l) 1189 { 1190 KASSERT(lwp_locked(l, NULL)); 1191 1192 l->l_flag |= LW_PENDSIG; 1193 lwp_need_userret(l); 1194 } 1195 1196 /* 1197 * Find an LWP within process p that is waiting on signal ksi, and hand 1198 * it on. 1199 */ 1200 static int 1201 sigunwait(struct proc *p, const ksiginfo_t *ksi) 1202 { 1203 struct lwp *l; 1204 int signo; 1205 1206 KASSERT(mutex_owned(p->p_lock)); 1207 1208 signo = ksi->ksi_signo; 1209 1210 if (ksi->ksi_lid != 0) { 1211 /* 1212 * Signal came via _lwp_kill(). Find the LWP and see if 1213 * it's interested. 1214 */ 1215 if ((l = lwp_find(p, ksi->ksi_lid)) == NULL) 1216 return 0; 1217 if (l->l_sigwaited == NULL || 1218 !sigismember(&l->l_sigwaitset, signo)) 1219 return 0; 1220 } else { 1221 /* 1222 * Look for any LWP that may be interested. 1223 */ 1224 LIST_FOREACH(l, &p->p_sigwaiters, l_sigwaiter) { 1225 KASSERT(l->l_sigwaited != NULL); 1226 if (sigismember(&l->l_sigwaitset, signo)) 1227 break; 1228 } 1229 } 1230 1231 if (l != NULL) { 1232 l->l_sigwaited->ksi_info = ksi->ksi_info; 1233 l->l_sigwaited = NULL; 1234 LIST_REMOVE(l, l_sigwaiter); 1235 cv_signal(&l->l_sigcv); 1236 return 1; 1237 } 1238 1239 return 0; 1240 } 1241 1242 /* 1243 * Send the signal to the process. If the signal has an action, the action 1244 * is usually performed by the target process rather than the caller; we add 1245 * the signal to the set of pending signals for the process. 1246 * 1247 * Exceptions: 1248 * o When a stop signal is sent to a sleeping process that takes the 1249 * default action, the process is stopped without awakening it. 1250 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1251 * regardless of the signal action (eg, blocked or ignored). 1252 * 1253 * Other ignored signals are discarded immediately. 1254 */ 1255 int 1256 kpsignal2(struct proc *p, ksiginfo_t *ksi) 1257 { 1258 int prop, signo = ksi->ksi_signo; 1259 struct lwp *l = NULL; 1260 ksiginfo_t *kp; 1261 lwpid_t lid; 1262 sig_t action; 1263 bool toall; 1264 int error = 0; 1265 1266 KASSERT(!cpu_intr_p()); 1267 KASSERT(mutex_owned(proc_lock)); 1268 KASSERT(mutex_owned(p->p_lock)); 1269 KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); 1270 KASSERT(signo > 0 && signo < NSIG); 1271 1272 /* 1273 * If the process is being created by fork, is a zombie or is 1274 * exiting, then just drop the signal here and bail out. 1275 */ 1276 if (p->p_stat != SACTIVE && p->p_stat != SSTOP) 1277 return 0; 1278 1279 /* XXX for core dump/debugger */ 1280 p->p_sigctx.ps_lwp = ksi->ksi_lid; 1281 p->p_sigctx.ps_info = ksi->ksi_info; 1282 1283 /* 1284 * Notify any interested parties of the signal. 1285 */ 1286 KNOTE(&p->p_klist, NOTE_SIGNAL | signo); 1287 1288 /* 1289 * Some signals including SIGKILL must act on the entire process. 1290 */ 1291 kp = NULL; 1292 prop = sigprop[signo]; 1293 toall = ((prop & SA_TOALL) != 0); 1294 lid = toall ? 0 : ksi->ksi_lid; 1295 1296 /* 1297 * If proc is traced, always give parent a chance. 1298 */ 1299 if (p->p_slflag & PSL_TRACED) { 1300 action = SIG_DFL; 1301 1302 if (lid == 0) { 1303 /* 1304 * If the process is being traced and the signal 1305 * is being caught, make sure to save any ksiginfo. 1306 */ 1307 if ((kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1308 goto discard; 1309 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1310 goto out; 1311 } 1312 } else { 1313 1314 /* 1315 * If the signal is being ignored, then drop it. Note: we 1316 * don't set SIGCONT in ps_sigignore, and if it is set to 1317 * SIG_IGN, action will be SIG_DFL here. 1318 */ 1319 if (sigismember(&p->p_sigctx.ps_sigignore, signo)) 1320 goto discard; 1321 1322 else if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) 1323 action = SIG_CATCH; 1324 else { 1325 action = SIG_DFL; 1326 1327 /* 1328 * If sending a tty stop signal to a member of an 1329 * orphaned process group, discard the signal here if 1330 * the action is default; don't stop the process below 1331 * if sleeping, and don't clear any pending SIGCONT. 1332 */ 1333 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0) 1334 goto discard; 1335 1336 if (prop & SA_KILL && p->p_nice > NZERO) 1337 p->p_nice = NZERO; 1338 } 1339 } 1340 1341 /* 1342 * If stopping or continuing a process, discard any pending 1343 * signals that would do the inverse. 1344 */ 1345 if ((prop & (SA_CONT | SA_STOP)) != 0) { 1346 ksiginfoq_t kq; 1347 1348 ksiginfo_queue_init(&kq); 1349 if ((prop & SA_CONT) != 0) 1350 sigclear(&p->p_sigpend, &stopsigmask, &kq); 1351 if ((prop & SA_STOP) != 0) 1352 sigclear(&p->p_sigpend, &contsigmask, &kq); 1353 ksiginfo_queue_drain(&kq); /* XXXSMP */ 1354 } 1355 1356 /* 1357 * If the signal doesn't have SA_CANTMASK (no override for SIGKILL, 1358 * please!), check if any LWPs are waiting on it. If yes, pass on 1359 * the signal info. The signal won't be processed further here. 1360 */ 1361 if ((prop & SA_CANTMASK) == 0 && !LIST_EMPTY(&p->p_sigwaiters) && 1362 p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0 && 1363 sigunwait(p, ksi)) 1364 goto discard; 1365 1366 /* 1367 * XXXSMP Should be allocated by the caller, we're holding locks 1368 * here. 1369 */ 1370 if (kp == NULL && (kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1371 goto discard; 1372 1373 /* 1374 * LWP private signals are easy - just find the LWP and post 1375 * the signal to it. 1376 */ 1377 if (lid != 0) { 1378 l = lwp_find(p, lid); 1379 if (l != NULL) { 1380 if ((error = sigput(&l->l_sigpend, p, kp)) != 0) 1381 goto out; 1382 membar_producer(); 1383 if (sigpost(l, action, prop, kp->ksi_signo) != 0) 1384 signo = -1; 1385 } 1386 goto out; 1387 } 1388 1389 /* 1390 * Some signals go to all LWPs, even if posted with _lwp_kill() 1391 * or for an SA process. 1392 */ 1393 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1394 if ((p->p_slflag & PSL_TRACED) != 0) 1395 goto deliver; 1396 1397 /* 1398 * If SIGCONT is default (or ignored) and process is 1399 * asleep, we are finished; the process should not 1400 * be awakened. 1401 */ 1402 if ((prop & SA_CONT) != 0 && action == SIG_DFL) 1403 goto out; 1404 } else { 1405 /* 1406 * Process is stopped or stopping. 1407 * - If traced, then no action is needed, unless killing. 1408 * - Run the process only if sending SIGCONT or SIGKILL. 1409 */ 1410 if ((p->p_slflag & PSL_TRACED) != 0 && signo != SIGKILL) { 1411 goto out; 1412 } 1413 if ((prop & SA_CONT) != 0 || signo == SIGKILL) { 1414 /* 1415 * Re-adjust p_nstopchild if the process was 1416 * stopped but not yet collected by its parent. 1417 */ 1418 if (p->p_stat == SSTOP && !p->p_waited) 1419 p->p_pptr->p_nstopchild--; 1420 p->p_stat = SACTIVE; 1421 p->p_sflag &= ~PS_STOPPING; 1422 if (p->p_slflag & PSL_TRACED) { 1423 KASSERT(signo == SIGKILL); 1424 goto deliver; 1425 } 1426 /* 1427 * Do not make signal pending if SIGCONT is default. 1428 * 1429 * If the process catches SIGCONT, let it handle the 1430 * signal itself (if waiting on event - process runs, 1431 * otherwise continues sleeping). 1432 */ 1433 if ((prop & SA_CONT) != 0) { 1434 p->p_xsig = SIGCONT; 1435 p->p_sflag |= PS_CONTINUED; 1436 child_psignal(p, 0); 1437 if (action == SIG_DFL) { 1438 KASSERT(signo != SIGKILL); 1439 goto deliver; 1440 } 1441 } 1442 } else if ((prop & SA_STOP) != 0) { 1443 /* 1444 * Already stopped, don't need to stop again. 1445 * (If we did the shell could get confused.) 1446 */ 1447 goto out; 1448 } 1449 } 1450 /* 1451 * Make signal pending. 1452 */ 1453 KASSERT((p->p_slflag & PSL_TRACED) == 0); 1454 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1455 goto out; 1456 deliver: 1457 /* 1458 * Before we set LW_PENDSIG on any LWP, ensure that the signal is 1459 * visible on the per process list (for sigispending()). This 1460 * is unlikely to be needed in practice, but... 1461 */ 1462 membar_producer(); 1463 1464 /* 1465 * Try to find an LWP that can take the signal. 1466 */ 1467 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1468 if (sigpost(l, action, prop, kp->ksi_signo) && !toall) 1469 break; 1470 } 1471 signo = -1; 1472 out: 1473 /* 1474 * If the ksiginfo wasn't used, then bin it. XXXSMP freeing memory 1475 * with locks held. The caller should take care of this. 1476 */ 1477 ksiginfo_free(kp); 1478 if (signo == -1) 1479 return error; 1480 discard: 1481 SDT_PROBE(proc, kernel, , signal__discard, l, p, signo, 0, 0); 1482 return error; 1483 } 1484 1485 void 1486 kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask) 1487 { 1488 struct proc *p = l->l_proc; 1489 1490 KASSERT(mutex_owned(p->p_lock)); 1491 (*p->p_emul->e_sendsig)(ksi, mask); 1492 } 1493 1494 /* 1495 * Stop any LWPs sleeping interruptably. 1496 */ 1497 static void 1498 proc_stop_lwps(struct proc *p) 1499 { 1500 struct lwp *l; 1501 1502 KASSERT(mutex_owned(p->p_lock)); 1503 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1504 1505 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1506 lwp_lock(l); 1507 if (l->l_stat == LSSLEEP && (l->l_flag & LW_SINTR) != 0) { 1508 l->l_stat = LSSTOP; 1509 p->p_nrlwps--; 1510 } 1511 lwp_unlock(l); 1512 } 1513 } 1514 1515 /* 1516 * Finish stopping of a process. Mark it stopped and notify the parent. 1517 * 1518 * Drop p_lock briefly if PS_NOTIFYSTOP is set and ppsig is true. 1519 */ 1520 static void 1521 proc_stop_done(struct proc *p, int ppmask) 1522 { 1523 1524 KASSERT(mutex_owned(proc_lock)); 1525 KASSERT(mutex_owned(p->p_lock)); 1526 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1527 KASSERT(p->p_nrlwps == 0 || (p->p_nrlwps == 1 && p == curproc)); 1528 1529 p->p_sflag &= ~PS_STOPPING; 1530 p->p_stat = SSTOP; 1531 p->p_waited = 0; 1532 p->p_pptr->p_nstopchild++; 1533 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 1534 /* child_psignal drops p_lock briefly. */ 1535 child_psignal(p, ppmask); 1536 cv_broadcast(&p->p_pptr->p_waitcv); 1537 } 1538 } 1539 1540 /* 1541 * Stop the current process and switch away when being stopped or traced. 1542 */ 1543 void 1544 sigswitch(int ppmask, int signo, bool relock) 1545 { 1546 struct lwp *l = curlwp; 1547 struct proc *p = l->l_proc; 1548 int biglocks; 1549 1550 KASSERT(mutex_owned(p->p_lock)); 1551 KASSERT(l->l_stat == LSONPROC); 1552 KASSERT(p->p_nrlwps > 0); 1553 1554 /* 1555 * On entry we know that the process needs to stop. If it's 1556 * the result of a 'sideways' stop signal that has been sourced 1557 * through issignal(), then stop other LWPs in the process too. 1558 */ 1559 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1560 KASSERT(signo != 0); 1561 proc_stop(p, signo); 1562 KASSERT(p->p_nrlwps > 0); 1563 } 1564 1565 /* 1566 * If we are the last live LWP, and the stop was a result of 1567 * a new signal, then signal the parent. 1568 */ 1569 if ((p->p_sflag & PS_STOPPING) != 0) { 1570 if (relock && !mutex_tryenter(proc_lock)) { 1571 mutex_exit(p->p_lock); 1572 mutex_enter(proc_lock); 1573 mutex_enter(p->p_lock); 1574 } 1575 1576 if (p->p_nrlwps == 1 && (p->p_sflag & PS_STOPPING) != 0) { 1577 /* 1578 * Note that proc_stop_done() can drop 1579 * p->p_lock briefly. 1580 */ 1581 proc_stop_done(p, ppmask); 1582 } 1583 1584 mutex_exit(proc_lock); 1585 } 1586 1587 /* 1588 * Unlock and switch away. 1589 */ 1590 KERNEL_UNLOCK_ALL(l, &biglocks); 1591 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1592 p->p_nrlwps--; 1593 lwp_lock(l); 1594 KASSERT(l->l_stat == LSONPROC || l->l_stat == LSSLEEP); 1595 l->l_stat = LSSTOP; 1596 lwp_unlock(l); 1597 } 1598 1599 mutex_exit(p->p_lock); 1600 lwp_lock(l); 1601 mi_switch(l); 1602 KERNEL_LOCK(biglocks, l); 1603 mutex_enter(p->p_lock); 1604 } 1605 1606 /* 1607 * Check for a signal from the debugger. 1608 */ 1609 static int 1610 sigchecktrace(void) 1611 { 1612 struct lwp *l = curlwp; 1613 struct proc *p = l->l_proc; 1614 int signo; 1615 1616 KASSERT(mutex_owned(p->p_lock)); 1617 1618 /* If there's a pending SIGKILL, process it immediately. */ 1619 if (sigismember(&p->p_sigpend.sp_set, SIGKILL)) 1620 return 0; 1621 1622 /* 1623 * If we are no longer being traced, or the parent didn't 1624 * give us a signal, or we're stopping, look for more signals. 1625 */ 1626 if ((p->p_slflag & PSL_TRACED) == 0 || p->p_xsig == 0 || 1627 (p->p_sflag & PS_STOPPING) != 0) 1628 return 0; 1629 1630 /* 1631 * If the new signal is being masked, look for other signals. 1632 * `p->p_sigctx.ps_siglist |= mask' is done in setrunnable(). 1633 */ 1634 signo = p->p_xsig; 1635 p->p_xsig = 0; 1636 if (sigismember(&l->l_sigmask, signo)) { 1637 signo = 0; 1638 } 1639 return signo; 1640 } 1641 1642 /* 1643 * If the current process has received a signal (should be caught or cause 1644 * termination, should interrupt current syscall), return the signal number. 1645 * 1646 * Stop signals with default action are processed immediately, then cleared; 1647 * they aren't returned. This is checked after each entry to the system for 1648 * a syscall or trap. 1649 * 1650 * We will also return -1 if the process is exiting and the current LWP must 1651 * follow suit. 1652 */ 1653 int 1654 issignal(struct lwp *l) 1655 { 1656 struct proc *p; 1657 int signo, prop; 1658 sigpend_t *sp; 1659 sigset_t ss; 1660 1661 p = l->l_proc; 1662 sp = NULL; 1663 signo = 0; 1664 1665 KASSERT(p == curproc); 1666 KASSERT(mutex_owned(p->p_lock)); 1667 1668 for (;;) { 1669 /* Discard any signals that we have decided not to take. */ 1670 if (signo != 0) { 1671 (void)sigget(sp, NULL, signo, NULL); 1672 } 1673 1674 /* 1675 * If the process is stopped/stopping, then stop ourselves 1676 * now that we're on the kernel/userspace boundary. When 1677 * we awaken, check for a signal from the debugger. 1678 */ 1679 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1680 sigswitch(PS_NOCLDSTOP, 0, true); 1681 signo = sigchecktrace(); 1682 } else if (p->p_stat == SACTIVE) 1683 signo = sigchecktrace(); 1684 else 1685 signo = 0; 1686 1687 /* Signals from the debugger are "out of band". */ 1688 sp = NULL; 1689 1690 /* 1691 * If the debugger didn't provide a signal, find a pending 1692 * signal from our set. Check per-LWP signals first, and 1693 * then per-process. 1694 */ 1695 if (signo == 0) { 1696 sp = &l->l_sigpend; 1697 ss = sp->sp_set; 1698 if ((p->p_lflag & PL_PPWAIT) != 0) 1699 sigminusset(&vforksigmask, &ss); 1700 sigminusset(&l->l_sigmask, &ss); 1701 1702 if ((signo = firstsig(&ss)) == 0) { 1703 sp = &p->p_sigpend; 1704 ss = sp->sp_set; 1705 if ((p->p_lflag & PL_PPWAIT) != 0) 1706 sigminusset(&vforksigmask, &ss); 1707 sigminusset(&l->l_sigmask, &ss); 1708 1709 if ((signo = firstsig(&ss)) == 0) { 1710 /* 1711 * No signal pending - clear the 1712 * indicator and bail out. 1713 */ 1714 lwp_lock(l); 1715 l->l_flag &= ~LW_PENDSIG; 1716 lwp_unlock(l); 1717 sp = NULL; 1718 break; 1719 } 1720 } 1721 } 1722 1723 /* 1724 * We should see pending but ignored signals only if 1725 * we are being traced. 1726 */ 1727 if (sigismember(&p->p_sigctx.ps_sigignore, signo) && 1728 (p->p_slflag & PSL_TRACED) == 0) { 1729 /* Discard the signal. */ 1730 continue; 1731 } 1732 1733 /* 1734 * If traced, always stop, and stay stopped until released 1735 * by the debugger. If the our parent is our debugger waiting 1736 * for us and we vforked, don't hang as we could deadlock. 1737 */ 1738 if (ISSET(p->p_slflag, PSL_TRACED) && signo != SIGKILL && 1739 !(ISSET(p->p_lflag, PL_PPWAIT) && 1740 (p->p_pptr == p->p_opptr))) { 1741 /* 1742 * Take the signal, but don't remove it from the 1743 * siginfo queue, because the debugger can send 1744 * it later. 1745 */ 1746 if (sp) 1747 sigdelset(&sp->sp_set, signo); 1748 p->p_xsig = signo; 1749 1750 /* Handling of signal trace */ 1751 sigswitch(0, signo, true); 1752 1753 /* Check for a signal from the debugger. */ 1754 if ((signo = sigchecktrace()) == 0) 1755 continue; 1756 1757 /* Signals from the debugger are "out of band". */ 1758 sp = NULL; 1759 } 1760 1761 prop = sigprop[signo]; 1762 1763 /* 1764 * Decide whether the signal should be returned. 1765 */ 1766 switch ((long)SIGACTION(p, signo).sa_handler) { 1767 case (long)SIG_DFL: 1768 /* 1769 * Don't take default actions on system processes. 1770 */ 1771 if (p->p_pid <= 1) { 1772 #ifdef DIAGNOSTIC 1773 /* 1774 * Are you sure you want to ignore SIGSEGV 1775 * in init? XXX 1776 */ 1777 printf_nolog("Process (pid %d) got sig %d\n", 1778 p->p_pid, signo); 1779 #endif 1780 continue; 1781 } 1782 1783 /* 1784 * If there is a pending stop signal to process with 1785 * default action, stop here, then clear the signal. 1786 * However, if process is member of an orphaned 1787 * process group, ignore tty stop signals. 1788 */ 1789 if (prop & SA_STOP) { 1790 /* 1791 * XXX Don't hold proc_lock for p_lflag, 1792 * but it's not a big deal. 1793 */ 1794 if ((ISSET(p->p_slflag, PSL_TRACED) && 1795 !(ISSET(p->p_lflag, PL_PPWAIT) && 1796 (p->p_pptr == p->p_opptr))) || 1797 ((p->p_lflag & PL_ORPHANPG) != 0 && 1798 prop & SA_TTYSTOP)) { 1799 /* Ignore the signal. */ 1800 continue; 1801 } 1802 /* Take the signal. */ 1803 (void)sigget(sp, NULL, signo, NULL); 1804 p->p_xsig = signo; 1805 p->p_sflag &= ~PS_CONTINUED; 1806 signo = 0; 1807 sigswitch(PS_NOCLDSTOP, p->p_xsig, true); 1808 } else if (prop & SA_IGNORE) { 1809 /* 1810 * Except for SIGCONT, shouldn't get here. 1811 * Default action is to ignore; drop it. 1812 */ 1813 continue; 1814 } 1815 break; 1816 1817 case (long)SIG_IGN: 1818 #ifdef DEBUG_ISSIGNAL 1819 /* 1820 * Masking above should prevent us ever trying 1821 * to take action on an ignored signal other 1822 * than SIGCONT, unless process is traced. 1823 */ 1824 if ((prop & SA_CONT) == 0 && 1825 (p->p_slflag & PSL_TRACED) == 0) 1826 printf_nolog("issignal\n"); 1827 #endif 1828 continue; 1829 1830 default: 1831 /* 1832 * This signal has an action, let postsig() process 1833 * it. 1834 */ 1835 break; 1836 } 1837 1838 break; 1839 } 1840 1841 l->l_sigpendset = sp; 1842 return signo; 1843 } 1844 1845 /* 1846 * Take the action for the specified signal 1847 * from the current set of pending signals. 1848 */ 1849 void 1850 postsig(int signo) 1851 { 1852 struct lwp *l; 1853 struct proc *p; 1854 struct sigacts *ps; 1855 sig_t action; 1856 sigset_t *returnmask; 1857 ksiginfo_t ksi; 1858 1859 l = curlwp; 1860 p = l->l_proc; 1861 ps = p->p_sigacts; 1862 1863 KASSERT(mutex_owned(p->p_lock)); 1864 KASSERT(signo > 0); 1865 1866 /* 1867 * Set the new mask value and also defer further occurrences of this 1868 * signal. 1869 * 1870 * Special case: user has done a sigsuspend. Here the current mask is 1871 * not of interest, but rather the mask from before the sigsuspend is 1872 * what we want restored after the signal processing is completed. 1873 */ 1874 if (l->l_sigrestore) { 1875 returnmask = &l->l_sigoldmask; 1876 l->l_sigrestore = 0; 1877 } else 1878 returnmask = &l->l_sigmask; 1879 1880 /* 1881 * Commit to taking the signal before releasing the mutex. 1882 */ 1883 action = SIGACTION_PS(ps, signo).sa_handler; 1884 l->l_ru.ru_nsignals++; 1885 if (l->l_sigpendset == NULL) { 1886 /* From the debugger */ 1887 if (p->p_sigctx.ps_faked && 1888 signo == p->p_sigctx.ps_info._signo) { 1889 KSI_INIT(&ksi); 1890 ksi.ksi_info = p->p_sigctx.ps_info; 1891 ksi.ksi_lid = p->p_sigctx.ps_lwp; 1892 p->p_sigctx.ps_faked = false; 1893 } else { 1894 if (!siggetinfo(&l->l_sigpend, &ksi, signo)) 1895 (void)siggetinfo(&p->p_sigpend, &ksi, signo); 1896 } 1897 } else 1898 sigget(l->l_sigpendset, &ksi, signo, NULL); 1899 1900 if (ktrpoint(KTR_PSIG)) { 1901 mutex_exit(p->p_lock); 1902 if (p->p_emul->e_ktrpsig) 1903 p->p_emul->e_ktrpsig(signo, action, 1904 returnmask, &ksi); 1905 else 1906 ktrpsig(signo, action, returnmask, &ksi); 1907 mutex_enter(p->p_lock); 1908 } 1909 1910 SDT_PROBE(proc, kernel, , signal__handle, signo, &ksi, action, 0, 0); 1911 1912 if (action == SIG_DFL) { 1913 /* 1914 * Default action, where the default is to kill 1915 * the process. (Other cases were ignored above.) 1916 */ 1917 sigexit(l, signo); 1918 return; 1919 } 1920 1921 /* 1922 * If we get here, the signal must be caught. 1923 */ 1924 #ifdef DIAGNOSTIC 1925 if (action == SIG_IGN || sigismember(&l->l_sigmask, signo)) 1926 panic("postsig action"); 1927 #endif 1928 1929 kpsendsig(l, &ksi, returnmask); 1930 } 1931 1932 /* 1933 * sendsig: 1934 * 1935 * Default signal delivery method for NetBSD. 1936 */ 1937 void 1938 sendsig(const struct ksiginfo *ksi, const sigset_t *mask) 1939 { 1940 struct sigacts *sa; 1941 int sig; 1942 1943 sig = ksi->ksi_signo; 1944 sa = curproc->p_sigacts; 1945 1946 switch (sa->sa_sigdesc[sig].sd_vers) { 1947 case 0: 1948 case 1: 1949 /* Compat for 1.6 and earlier. */ 1950 if (sendsig_sigcontext_vec == NULL) { 1951 break; 1952 } 1953 (*sendsig_sigcontext_vec)(ksi, mask); 1954 return; 1955 case 2: 1956 case 3: 1957 sendsig_siginfo(ksi, mask); 1958 return; 1959 default: 1960 break; 1961 } 1962 1963 printf("sendsig: bad version %d\n", sa->sa_sigdesc[sig].sd_vers); 1964 sigexit(curlwp, SIGILL); 1965 } 1966 1967 /* 1968 * sendsig_reset: 1969 * 1970 * Reset the signal action. Called from emulation specific sendsig() 1971 * before unlocking to deliver the signal. 1972 */ 1973 void 1974 sendsig_reset(struct lwp *l, int signo) 1975 { 1976 struct proc *p = l->l_proc; 1977 struct sigacts *ps = p->p_sigacts; 1978 1979 KASSERT(mutex_owned(p->p_lock)); 1980 1981 p->p_sigctx.ps_lwp = 0; 1982 memset(&p->p_sigctx.ps_info, 0, sizeof(p->p_sigctx.ps_info)); 1983 1984 mutex_enter(&ps->sa_mutex); 1985 sigplusset(&SIGACTION_PS(ps, signo).sa_mask, &l->l_sigmask); 1986 if (SIGACTION_PS(ps, signo).sa_flags & SA_RESETHAND) { 1987 sigdelset(&p->p_sigctx.ps_sigcatch, signo); 1988 if (signo != SIGCONT && sigprop[signo] & SA_IGNORE) 1989 sigaddset(&p->p_sigctx.ps_sigignore, signo); 1990 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 1991 } 1992 mutex_exit(&ps->sa_mutex); 1993 } 1994 1995 /* 1996 * Kill the current process for stated reason. 1997 */ 1998 void 1999 killproc(struct proc *p, const char *why) 2000 { 2001 2002 KASSERT(mutex_owned(proc_lock)); 2003 2004 log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why); 2005 uprintf_locked("sorry, pid %d was killed: %s\n", p->p_pid, why); 2006 psignal(p, SIGKILL); 2007 } 2008 2009 /* 2010 * Force the current process to exit with the specified signal, dumping core 2011 * if appropriate. We bypass the normal tests for masked and caught 2012 * signals, allowing unrecoverable failures to terminate the process without 2013 * changing signal state. Mark the accounting record with the signal 2014 * termination. If dumping core, save the signal number for the debugger. 2015 * Calls exit and does not return. 2016 */ 2017 void 2018 sigexit(struct lwp *l, int signo) 2019 { 2020 int exitsig, error, docore; 2021 struct proc *p; 2022 struct lwp *t; 2023 2024 p = l->l_proc; 2025 2026 KASSERT(mutex_owned(p->p_lock)); 2027 KERNEL_UNLOCK_ALL(l, NULL); 2028 2029 /* 2030 * Don't permit coredump() multiple times in the same process. 2031 * Call back into sigexit, where we will be suspended until 2032 * the deed is done. Note that this is a recursive call, but 2033 * LW_WCORE will prevent us from coming back this way. 2034 */ 2035 if ((p->p_sflag & PS_WCORE) != 0) { 2036 lwp_lock(l); 2037 l->l_flag |= (LW_WCORE | LW_WEXIT | LW_WSUSPEND); 2038 lwp_unlock(l); 2039 mutex_exit(p->p_lock); 2040 lwp_userret(l); 2041 panic("sigexit 1"); 2042 /* NOTREACHED */ 2043 } 2044 2045 /* If process is already on the way out, then bail now. */ 2046 if ((p->p_sflag & PS_WEXIT) != 0) { 2047 mutex_exit(p->p_lock); 2048 lwp_exit(l); 2049 panic("sigexit 2"); 2050 /* NOTREACHED */ 2051 } 2052 2053 /* 2054 * Prepare all other LWPs for exit. If dumping core, suspend them 2055 * so that their registers are available long enough to be dumped. 2056 */ 2057 if ((docore = (sigprop[signo] & SA_CORE)) != 0) { 2058 p->p_sflag |= PS_WCORE; 2059 for (;;) { 2060 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 2061 lwp_lock(t); 2062 if (t == l) { 2063 t->l_flag &= ~LW_WSUSPEND; 2064 lwp_unlock(t); 2065 continue; 2066 } 2067 t->l_flag |= (LW_WCORE | LW_WEXIT); 2068 lwp_suspend(l, t); 2069 } 2070 2071 if (p->p_nrlwps == 1) 2072 break; 2073 2074 /* 2075 * Kick any LWPs sitting in lwp_wait1(), and wait 2076 * for everyone else to stop before proceeding. 2077 */ 2078 p->p_nlwpwait++; 2079 cv_broadcast(&p->p_lwpcv); 2080 cv_wait(&p->p_lwpcv, p->p_lock); 2081 p->p_nlwpwait--; 2082 } 2083 } 2084 2085 exitsig = signo; 2086 p->p_acflag |= AXSIG; 2087 memset(&p->p_sigctx.ps_info, 0, sizeof(p->p_sigctx.ps_info)); 2088 p->p_sigctx.ps_info._signo = signo; 2089 p->p_sigctx.ps_info._code = SI_NOINFO; 2090 2091 if (docore) { 2092 mutex_exit(p->p_lock); 2093 error = (*coredump_vec)(l, NULL); 2094 2095 if (kern_logsigexit) { 2096 int uid = l->l_cred ? 2097 (int)kauth_cred_geteuid(l->l_cred) : -1; 2098 2099 if (error) 2100 log(LOG_INFO, lognocoredump, p->p_pid, 2101 p->p_comm, uid, signo, error); 2102 else 2103 log(LOG_INFO, logcoredump, p->p_pid, 2104 p->p_comm, uid, signo); 2105 } 2106 2107 #ifdef PAX_SEGVGUARD 2108 pax_segvguard(l, p->p_textvp, p->p_comm, true); 2109 #endif /* PAX_SEGVGUARD */ 2110 /* Acquire the sched state mutex. exit1() will release it. */ 2111 mutex_enter(p->p_lock); 2112 if (error == 0) 2113 p->p_sflag |= PS_COREDUMP; 2114 } 2115 2116 /* No longer dumping core. */ 2117 p->p_sflag &= ~PS_WCORE; 2118 2119 exit1(l, 0, exitsig); 2120 /* NOTREACHED */ 2121 } 2122 2123 /* 2124 * Put process 'p' into the stopped state and optionally, notify the parent. 2125 */ 2126 void 2127 proc_stop(struct proc *p, int signo) 2128 { 2129 struct lwp *l; 2130 2131 KASSERT(mutex_owned(p->p_lock)); 2132 2133 /* 2134 * First off, set the stopping indicator and bring all sleeping 2135 * LWPs to a halt so they are included in p->p_nrlwps. We musn't 2136 * unlock between here and the p->p_nrlwps check below. 2137 */ 2138 p->p_sflag |= PS_STOPPING | PS_NOTIFYSTOP; 2139 membar_producer(); 2140 2141 proc_stop_lwps(p); 2142 2143 /* 2144 * If there are no LWPs available to take the signal, then we 2145 * signal the parent process immediately. Otherwise, the last 2146 * LWP to stop will take care of it. 2147 */ 2148 2149 if (p->p_nrlwps == 0) { 2150 proc_stop_done(p, PS_NOCLDSTOP); 2151 } else { 2152 /* 2153 * Have the remaining LWPs come to a halt, and trigger 2154 * proc_stop_callout() to ensure that they do. 2155 */ 2156 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2157 sigpost(l, SIG_DFL, SA_STOP, signo); 2158 } 2159 callout_schedule(&proc_stop_ch, 1); 2160 } 2161 } 2162 2163 /* 2164 * When stopping a process, we do not immediatly set sleeping LWPs stopped, 2165 * but wait for them to come to a halt at the kernel-user boundary. This is 2166 * to allow LWPs to release any locks that they may hold before stopping. 2167 * 2168 * Non-interruptable sleeps can be long, and there is the potential for an 2169 * LWP to begin sleeping interruptably soon after the process has been set 2170 * stopping (PS_STOPPING). These LWPs will not notice that the process is 2171 * stopping, and so complete halt of the process and the return of status 2172 * information to the parent could be delayed indefinitely. 2173 * 2174 * To handle this race, proc_stop_callout() runs once per tick while there 2175 * are stopping processes in the system. It sets LWPs that are sleeping 2176 * interruptably into the LSSTOP state. 2177 * 2178 * Note that we are not concerned about keeping all LWPs stopped while the 2179 * process is stopped: stopped LWPs can awaken briefly to handle signals. 2180 * What we do need to ensure is that all LWPs in a stopping process have 2181 * stopped at least once, so that notification can be sent to the parent 2182 * process. 2183 */ 2184 static void 2185 proc_stop_callout(void *cookie) 2186 { 2187 bool more, restart; 2188 struct proc *p; 2189 2190 (void)cookie; 2191 2192 do { 2193 restart = false; 2194 more = false; 2195 2196 mutex_enter(proc_lock); 2197 PROCLIST_FOREACH(p, &allproc) { 2198 mutex_enter(p->p_lock); 2199 2200 if ((p->p_sflag & PS_STOPPING) == 0) { 2201 mutex_exit(p->p_lock); 2202 continue; 2203 } 2204 2205 /* Stop any LWPs sleeping interruptably. */ 2206 proc_stop_lwps(p); 2207 if (p->p_nrlwps == 0) { 2208 /* 2209 * We brought the process to a halt. 2210 * Mark it as stopped and notify the 2211 * parent. 2212 */ 2213 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 2214 /* 2215 * Note that proc_stop_done() will 2216 * drop p->p_lock briefly. 2217 * Arrange to restart and check 2218 * all processes again. 2219 */ 2220 restart = true; 2221 } 2222 proc_stop_done(p, PS_NOCLDSTOP); 2223 } else 2224 more = true; 2225 2226 mutex_exit(p->p_lock); 2227 if (restart) 2228 break; 2229 } 2230 mutex_exit(proc_lock); 2231 } while (restart); 2232 2233 /* 2234 * If we noted processes that are stopping but still have 2235 * running LWPs, then arrange to check again in 1 tick. 2236 */ 2237 if (more) 2238 callout_schedule(&proc_stop_ch, 1); 2239 } 2240 2241 /* 2242 * Given a process in state SSTOP, set the state back to SACTIVE and 2243 * move LSSTOP'd LWPs to LSSLEEP or make them runnable. 2244 */ 2245 void 2246 proc_unstop(struct proc *p) 2247 { 2248 struct lwp *l; 2249 int sig; 2250 2251 KASSERT(mutex_owned(proc_lock)); 2252 KASSERT(mutex_owned(p->p_lock)); 2253 2254 p->p_stat = SACTIVE; 2255 p->p_sflag &= ~PS_STOPPING; 2256 sig = p->p_xsig; 2257 2258 if (!p->p_waited) 2259 p->p_pptr->p_nstopchild--; 2260 2261 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2262 lwp_lock(l); 2263 if (l->l_stat != LSSTOP) { 2264 lwp_unlock(l); 2265 continue; 2266 } 2267 if (l->l_wchan == NULL) { 2268 setrunnable(l); 2269 continue; 2270 } 2271 if (sig && (l->l_flag & LW_SINTR) != 0) { 2272 setrunnable(l); 2273 sig = 0; 2274 } else { 2275 l->l_stat = LSSLEEP; 2276 p->p_nrlwps++; 2277 lwp_unlock(l); 2278 } 2279 } 2280 } 2281 2282 void 2283 proc_stoptrace(int trapno) 2284 { 2285 struct lwp *l = curlwp; 2286 struct proc *p = l->l_proc; 2287 struct sigacts *ps; 2288 sigset_t *mask; 2289 sig_t action; 2290 ksiginfo_t ksi; 2291 const int signo = SIGTRAP; 2292 2293 KASSERT((trapno == TRAP_SCE) || (trapno == TRAP_SCX)); 2294 2295 KSI_INIT_TRAP(&ksi); 2296 ksi.ksi_lid = l->l_lid; 2297 ksi.ksi_info._signo = signo; 2298 ksi.ksi_info._code = trapno; 2299 2300 mutex_enter(p->p_lock); 2301 2302 /* Needed for ktrace */ 2303 ps = p->p_sigacts; 2304 action = SIGACTION_PS(ps, signo).sa_handler; 2305 mask = &l->l_sigmask; 2306 2307 /* initproc (PID1) cannot became a debugger */ 2308 KASSERT(p->p_pptr != initproc); 2309 2310 KASSERT(ISSET(p->p_slflag, PSL_TRACED)); 2311 KASSERT(ISSET(p->p_slflag, PSL_SYSCALL)); 2312 2313 p->p_xsig = signo; 2314 p->p_sigctx.ps_lwp = ksi.ksi_lid; 2315 p->p_sigctx.ps_info = ksi.ksi_info; 2316 sigswitch(0, signo, true); 2317 mutex_exit(p->p_lock); 2318 2319 if (ktrpoint(KTR_PSIG)) { 2320 if (p->p_emul->e_ktrpsig) 2321 p->p_emul->e_ktrpsig(signo, action, mask, &ksi); 2322 else 2323 ktrpsig(signo, action, mask, &ksi); 2324 } 2325 } 2326 2327 static int 2328 filt_sigattach(struct knote *kn) 2329 { 2330 struct proc *p = curproc; 2331 2332 kn->kn_obj = p; 2333 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2334 2335 mutex_enter(p->p_lock); 2336 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2337 mutex_exit(p->p_lock); 2338 2339 return 0; 2340 } 2341 2342 static void 2343 filt_sigdetach(struct knote *kn) 2344 { 2345 struct proc *p = kn->kn_obj; 2346 2347 mutex_enter(p->p_lock); 2348 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2349 mutex_exit(p->p_lock); 2350 } 2351 2352 /* 2353 * Signal knotes are shared with proc knotes, so we apply a mask to 2354 * the hint in order to differentiate them from process hints. This 2355 * could be avoided by using a signal-specific knote list, but probably 2356 * isn't worth the trouble. 2357 */ 2358 static int 2359 filt_signal(struct knote *kn, long hint) 2360 { 2361 2362 if (hint & NOTE_SIGNAL) { 2363 hint &= ~NOTE_SIGNAL; 2364 2365 if (kn->kn_id == hint) 2366 kn->kn_data++; 2367 } 2368 return (kn->kn_data != 0); 2369 } 2370 2371 const struct filterops sig_filtops = { 2372 .f_isfd = 0, 2373 .f_attach = filt_sigattach, 2374 .f_detach = filt_sigdetach, 2375 .f_event = filt_signal, 2376 }; 2377
Indexes created Tue Sep 30 07:10:03 GMT 2025