kern_sig.c revision 1.328
1 /* $NetBSD: kern_sig.c,v 1.328 2016/08/04 06:43:43 christos 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 1.328 2016/08/04 06:43:43 christos 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/systm.h> 87 #include <sys/wait.h> 88 #include <sys/ktrace.h> 89 #include <sys/syslog.h> 90 #include <sys/filedesc.h> 91 #include <sys/file.h> 92 #include <sys/pool.h> 93 #include <sys/ucontext.h> 94 #include <sys/exec.h> 95 #include <sys/kauth.h> 96 #include <sys/acct.h> 97 #include <sys/callout.h> 98 #include <sys/atomic.h> 99 #include <sys/cpu.h> 100 #include <sys/module.h> 101 #include <sys/sdt.h> 102 103 #ifdef PAX_SEGVGUARD 104 #include <sys/pax.h> 105 #endif /* PAX_SEGVGUARD */ 106 107 #include <uvm/uvm_extern.h> 108 109 #define SIGQUEUE_MAX 32 110 static pool_cache_t sigacts_cache __read_mostly; 111 static pool_cache_t ksiginfo_cache __read_mostly; 112 static callout_t proc_stop_ch __cacheline_aligned; 113 114 sigset_t contsigmask __cacheline_aligned; 115 static sigset_t stopsigmask __cacheline_aligned; 116 sigset_t sigcantmask __cacheline_aligned; 117 118 static void ksiginfo_exechook(struct proc *, void *); 119 static void proc_stop_callout(void *); 120 static int sigchecktrace(void); 121 static int sigpost(struct lwp *, sig_t, int, int); 122 static int sigput(sigpend_t *, struct proc *, ksiginfo_t *); 123 static int sigunwait(struct proc *, const ksiginfo_t *); 124 static void sigswitch(bool, int, int); 125 126 static void sigacts_poolpage_free(struct pool *, void *); 127 static void *sigacts_poolpage_alloc(struct pool *, int); 128 129 void (*sendsig_sigcontext_vec)(const struct ksiginfo *, const sigset_t *); 130 int (*coredump_vec)(struct lwp *, const char *) = 131 (int (*)(struct lwp *, const char *))enosys; 132 133 /* 134 * DTrace SDT provider definitions 135 */ 136 SDT_PROVIDER_DECLARE(proc); 137 SDT_PROBE_DEFINE3(proc, kernel, , signal__send, 138 "struct lwp *", /* target thread */ 139 "struct proc *", /* target process */ 140 "int"); /* signal */ 141 SDT_PROBE_DEFINE3(proc, kernel, , signal__discard, 142 "struct lwp *", /* target thread */ 143 "struct proc *", /* target process */ 144 "int"); /* signal */ 145 SDT_PROBE_DEFINE3(proc, kernel, , signal__handle, 146 "int", /* signal */ 147 "ksiginfo_t *", /* signal info */ 148 "void (*)(void)"); /* handler address */ 149 150 151 static struct pool_allocator sigactspool_allocator = { 152 .pa_alloc = sigacts_poolpage_alloc, 153 .pa_free = sigacts_poolpage_free 154 }; 155 156 #ifdef DEBUG 157 int kern_logsigexit = 1; 158 #else 159 int kern_logsigexit = 0; 160 #endif 161 162 static const char logcoredump[] = 163 "pid %d (%s), uid %d: exited on signal %d (core dumped)\n"; 164 static const char lognocoredump[] = 165 "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n"; 166 167 static kauth_listener_t signal_listener; 168 169 static int 170 signal_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 171 void *arg0, void *arg1, void *arg2, void *arg3) 172 { 173 struct proc *p; 174 int result, signum; 175 176 result = KAUTH_RESULT_DEFER; 177 p = arg0; 178 signum = (int)(unsigned long)arg1; 179 180 if (action != KAUTH_PROCESS_SIGNAL) 181 return result; 182 183 if (kauth_cred_uidmatch(cred, p->p_cred) || 184 (signum == SIGCONT && (curproc->p_session == p->p_session))) 185 result = KAUTH_RESULT_ALLOW; 186 187 return result; 188 } 189 190 /* 191 * signal_init: 192 * 193 * Initialize global signal-related data structures. 194 */ 195 void 196 signal_init(void) 197 { 198 199 sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2; 200 201 sigacts_cache = pool_cache_init(sizeof(struct sigacts), 0, 0, 0, 202 "sigacts", sizeof(struct sigacts) > PAGE_SIZE ? 203 &sigactspool_allocator : NULL, IPL_NONE, NULL, NULL, NULL); 204 ksiginfo_cache = pool_cache_init(sizeof(ksiginfo_t), 0, 0, 0, 205 "ksiginfo", NULL, IPL_VM, NULL, NULL, NULL); 206 207 exechook_establish(ksiginfo_exechook, NULL); 208 209 callout_init(&proc_stop_ch, CALLOUT_MPSAFE); 210 callout_setfunc(&proc_stop_ch, proc_stop_callout, NULL); 211 212 signal_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS, 213 signal_listener_cb, NULL); 214 } 215 216 /* 217 * sigacts_poolpage_alloc: 218 * 219 * Allocate a page for the sigacts memory pool. 220 */ 221 static void * 222 sigacts_poolpage_alloc(struct pool *pp, int flags) 223 { 224 225 return (void *)uvm_km_alloc(kernel_map, 226 PAGE_SIZE * 2, PAGE_SIZE * 2, 227 ((flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK) 228 | UVM_KMF_WIRED); 229 } 230 231 /* 232 * sigacts_poolpage_free: 233 * 234 * Free a page on behalf of the sigacts memory pool. 235 */ 236 static void 237 sigacts_poolpage_free(struct pool *pp, void *v) 238 { 239 240 uvm_km_free(kernel_map, (vaddr_t)v, PAGE_SIZE * 2, UVM_KMF_WIRED); 241 } 242 243 /* 244 * sigactsinit: 245 * 246 * Create an initial sigacts structure, using the same signal state 247 * as of specified process. If 'share' is set, share the sigacts by 248 * holding a reference, otherwise just copy it from parent. 249 */ 250 struct sigacts * 251 sigactsinit(struct proc *pp, int share) 252 { 253 struct sigacts *ps = pp->p_sigacts, *ps2; 254 255 if (__predict_false(share)) { 256 atomic_inc_uint(&ps->sa_refcnt); 257 return ps; 258 } 259 ps2 = pool_cache_get(sigacts_cache, PR_WAITOK); 260 mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 261 ps2->sa_refcnt = 1; 262 263 mutex_enter(&ps->sa_mutex); 264 memcpy(ps2->sa_sigdesc, ps->sa_sigdesc, sizeof(ps2->sa_sigdesc)); 265 mutex_exit(&ps->sa_mutex); 266 return ps2; 267 } 268 269 /* 270 * sigactsunshare: 271 * 272 * Make this process not share its sigacts, maintaining all signal state. 273 */ 274 void 275 sigactsunshare(struct proc *p) 276 { 277 struct sigacts *ps, *oldps = p->p_sigacts; 278 279 if (__predict_true(oldps->sa_refcnt == 1)) 280 return; 281 282 ps = pool_cache_get(sigacts_cache, PR_WAITOK); 283 mutex_init(&ps->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 284 memcpy(ps->sa_sigdesc, oldps->sa_sigdesc, sizeof(ps->sa_sigdesc)); 285 ps->sa_refcnt = 1; 286 287 p->p_sigacts = ps; 288 sigactsfree(oldps); 289 } 290 291 /* 292 * sigactsfree; 293 * 294 * Release a sigacts structure. 295 */ 296 void 297 sigactsfree(struct sigacts *ps) 298 { 299 300 if (atomic_dec_uint_nv(&ps->sa_refcnt) == 0) { 301 mutex_destroy(&ps->sa_mutex); 302 pool_cache_put(sigacts_cache, ps); 303 } 304 } 305 306 /* 307 * siginit: 308 * 309 * Initialize signal state for process 0; set to ignore signals that 310 * are ignored by default and disable the signal stack. Locking not 311 * required as the system is still cold. 312 */ 313 void 314 siginit(struct proc *p) 315 { 316 struct lwp *l; 317 struct sigacts *ps; 318 int signo, prop; 319 320 ps = p->p_sigacts; 321 sigemptyset(&contsigmask); 322 sigemptyset(&stopsigmask); 323 sigemptyset(&sigcantmask); 324 for (signo = 1; signo < NSIG; signo++) { 325 prop = sigprop[signo]; 326 if (prop & SA_CONT) 327 sigaddset(&contsigmask, signo); 328 if (prop & SA_STOP) 329 sigaddset(&stopsigmask, signo); 330 if (prop & SA_CANTMASK) 331 sigaddset(&sigcantmask, signo); 332 if (prop & SA_IGNORE && signo != SIGCONT) 333 sigaddset(&p->p_sigctx.ps_sigignore, signo); 334 sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); 335 SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; 336 } 337 sigemptyset(&p->p_sigctx.ps_sigcatch); 338 p->p_sflag &= ~PS_NOCLDSTOP; 339 340 ksiginfo_queue_init(&p->p_sigpend.sp_info); 341 sigemptyset(&p->p_sigpend.sp_set); 342 343 /* 344 * Reset per LWP state. 345 */ 346 l = LIST_FIRST(&p->p_lwps); 347 l->l_sigwaited = NULL; 348 l->l_sigstk.ss_flags = SS_DISABLE; 349 l->l_sigstk.ss_size = 0; 350 l->l_sigstk.ss_sp = 0; 351 ksiginfo_queue_init(&l->l_sigpend.sp_info); 352 sigemptyset(&l->l_sigpend.sp_set); 353 354 /* One reference. */ 355 ps->sa_refcnt = 1; 356 } 357 358 /* 359 * execsigs: 360 * 361 * Reset signals for an exec of the specified process. 362 */ 363 void 364 execsigs(struct proc *p) 365 { 366 struct sigacts *ps; 367 struct lwp *l; 368 int signo, prop; 369 sigset_t tset; 370 ksiginfoq_t kq; 371 372 KASSERT(p->p_nlwps == 1); 373 374 sigactsunshare(p); 375 ps = p->p_sigacts; 376 377 /* 378 * Reset caught signals. Held signals remain held through 379 * l->l_sigmask (unless they were caught, and are now ignored 380 * by default). 381 * 382 * No need to lock yet, the process has only one LWP and 383 * at this point the sigacts are private to the process. 384 */ 385 sigemptyset(&tset); 386 for (signo = 1; signo < NSIG; signo++) { 387 if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) { 388 prop = sigprop[signo]; 389 if (prop & SA_IGNORE) { 390 if ((prop & SA_CONT) == 0) 391 sigaddset(&p->p_sigctx.ps_sigignore, 392 signo); 393 sigaddset(&tset, signo); 394 } 395 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 396 } 397 sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); 398 SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; 399 } 400 ksiginfo_queue_init(&kq); 401 402 mutex_enter(p->p_lock); 403 sigclearall(p, &tset, &kq); 404 sigemptyset(&p->p_sigctx.ps_sigcatch); 405 406 /* 407 * Reset no zombies if child dies flag as Solaris does. 408 */ 409 p->p_flag &= ~(PK_NOCLDWAIT | PK_CLDSIGIGN); 410 if (SIGACTION_PS(ps, SIGCHLD).sa_handler == SIG_IGN) 411 SIGACTION_PS(ps, SIGCHLD).sa_handler = SIG_DFL; 412 413 /* 414 * Reset per-LWP state. 415 */ 416 l = LIST_FIRST(&p->p_lwps); 417 l->l_sigwaited = NULL; 418 l->l_sigstk.ss_flags = SS_DISABLE; 419 l->l_sigstk.ss_size = 0; 420 l->l_sigstk.ss_sp = 0; 421 ksiginfo_queue_init(&l->l_sigpend.sp_info); 422 sigemptyset(&l->l_sigpend.sp_set); 423 mutex_exit(p->p_lock); 424 425 ksiginfo_queue_drain(&kq); 426 } 427 428 /* 429 * ksiginfo_exechook: 430 * 431 * Free all pending ksiginfo entries from a process on exec. 432 * Additionally, drain any unused ksiginfo structures in the 433 * system back to the pool. 434 * 435 * XXX This should not be a hook, every process has signals. 436 */ 437 static void 438 ksiginfo_exechook(struct proc *p, void *v) 439 { 440 ksiginfoq_t kq; 441 442 ksiginfo_queue_init(&kq); 443 444 mutex_enter(p->p_lock); 445 sigclearall(p, NULL, &kq); 446 mutex_exit(p->p_lock); 447 448 ksiginfo_queue_drain(&kq); 449 } 450 451 /* 452 * ksiginfo_alloc: 453 * 454 * Allocate a new ksiginfo structure from the pool, and optionally copy 455 * an existing one. If the existing ksiginfo_t is from the pool, and 456 * has not been queued somewhere, then just return it. Additionally, 457 * if the existing ksiginfo_t does not contain any information beyond 458 * the signal number, then just return it. 459 */ 460 ksiginfo_t * 461 ksiginfo_alloc(struct proc *p, ksiginfo_t *ok, int flags) 462 { 463 ksiginfo_t *kp; 464 465 if (ok != NULL) { 466 if ((ok->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) == 467 KSI_FROMPOOL) 468 return ok; 469 if (KSI_EMPTY_P(ok)) 470 return ok; 471 } 472 473 kp = pool_cache_get(ksiginfo_cache, flags); 474 if (kp == NULL) { 475 #ifdef DIAGNOSTIC 476 printf("Out of memory allocating ksiginfo for pid %d\n", 477 p->p_pid); 478 #endif 479 return NULL; 480 } 481 482 if (ok != NULL) { 483 memcpy(kp, ok, sizeof(*kp)); 484 kp->ksi_flags &= ~KSI_QUEUED; 485 } else 486 KSI_INIT_EMPTY(kp); 487 488 kp->ksi_flags |= KSI_FROMPOOL; 489 490 return kp; 491 } 492 493 /* 494 * ksiginfo_free: 495 * 496 * If the given ksiginfo_t is from the pool and has not been queued, 497 * then free it. 498 */ 499 void 500 ksiginfo_free(ksiginfo_t *kp) 501 { 502 503 if ((kp->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) != KSI_FROMPOOL) 504 return; 505 pool_cache_put(ksiginfo_cache, kp); 506 } 507 508 /* 509 * ksiginfo_queue_drain: 510 * 511 * Drain a non-empty ksiginfo_t queue. 512 */ 513 void 514 ksiginfo_queue_drain0(ksiginfoq_t *kq) 515 { 516 ksiginfo_t *ksi; 517 518 KASSERT(!TAILQ_EMPTY(kq)); 519 520 while (!TAILQ_EMPTY(kq)) { 521 ksi = TAILQ_FIRST(kq); 522 TAILQ_REMOVE(kq, ksi, ksi_list); 523 pool_cache_put(ksiginfo_cache, ksi); 524 } 525 } 526 527 static int 528 siggetinfo(sigpend_t *sp, ksiginfo_t *out, int signo) 529 { 530 ksiginfo_t *ksi; 531 532 if (sp == NULL) 533 goto out; 534 535 /* Find siginfo and copy it out. */ 536 int count = 0; 537 TAILQ_FOREACH(ksi, &sp->sp_info, ksi_list) { 538 if (ksi->ksi_signo != signo) 539 continue; 540 if (count++ > 0) /* Only remove the first, count all of them */ 541 continue; 542 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 543 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 544 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 545 ksi->ksi_flags &= ~KSI_QUEUED; 546 if (out != NULL) { 547 memcpy(out, ksi, sizeof(*out)); 548 out->ksi_flags &= ~(KSI_FROMPOOL | KSI_QUEUED); 549 } 550 ksiginfo_free(ksi); 551 } 552 if (count) 553 return count; 554 555 out: 556 /* If there is no siginfo, then manufacture it. */ 557 if (out != NULL) { 558 KSI_INIT(out); 559 out->ksi_info._signo = signo; 560 out->ksi_info._code = SI_NOINFO; 561 } 562 return 0; 563 } 564 565 /* 566 * sigget: 567 * 568 * Fetch the first pending signal from a set. Optionally, also fetch 569 * or manufacture a ksiginfo element. Returns the number of the first 570 * pending signal, or zero. 571 */ 572 int 573 sigget(sigpend_t *sp, ksiginfo_t *out, int signo, const sigset_t *mask) 574 { 575 sigset_t tset; 576 int count; 577 578 /* If there's no pending set, the signal is from the debugger. */ 579 if (sp == NULL) 580 goto out; 581 582 /* Construct mask from signo, and 'mask'. */ 583 if (signo == 0) { 584 if (mask != NULL) { 585 tset = *mask; 586 __sigandset(&sp->sp_set, &tset); 587 } else 588 tset = sp->sp_set; 589 590 /* If there are no signals pending - return. */ 591 if ((signo = firstsig(&tset)) == 0) 592 goto out; 593 } else { 594 KASSERT(sigismember(&sp->sp_set, signo)); 595 } 596 597 sigdelset(&sp->sp_set, signo); 598 out: 599 count = siggetinfo(sp, out, signo); 600 if (count > 1) 601 sigaddset(&sp->sp_set, signo); 602 return signo; 603 } 604 605 /* 606 * sigput: 607 * 608 * Append a new ksiginfo element to the list of pending ksiginfo's. 609 */ 610 static int 611 sigput(sigpend_t *sp, struct proc *p, ksiginfo_t *ksi) 612 { 613 ksiginfo_t *kp; 614 615 KASSERT(mutex_owned(p->p_lock)); 616 KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); 617 618 sigaddset(&sp->sp_set, ksi->ksi_signo); 619 620 /* 621 * If there is no siginfo, we are done. 622 */ 623 if (KSI_EMPTY_P(ksi)) 624 return 0; 625 626 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 627 628 size_t count = 0; 629 TAILQ_FOREACH(kp, &sp->sp_info, ksi_list) { 630 count++; 631 if (ksi->ksi_signo >= SIGRTMIN && ksi->ksi_signo <= SIGRTMAX) 632 continue; 633 if (kp->ksi_signo == ksi->ksi_signo) { 634 KSI_COPY(ksi, kp); 635 kp->ksi_flags |= KSI_QUEUED; 636 return 0; 637 } 638 } 639 640 if (count >= SIGQUEUE_MAX) { 641 #ifdef DIAGNOSTIC 642 printf("%s(%d): Signal queue is full signal=%d\n", 643 p->p_comm, p->p_pid, ksi->ksi_signo); 644 #endif 645 return EAGAIN; 646 } 647 ksi->ksi_flags |= KSI_QUEUED; 648 TAILQ_INSERT_TAIL(&sp->sp_info, ksi, ksi_list); 649 650 return 0; 651 } 652 653 /* 654 * sigclear: 655 * 656 * Clear all pending signals in the specified set. 657 */ 658 void 659 sigclear(sigpend_t *sp, const sigset_t *mask, ksiginfoq_t *kq) 660 { 661 ksiginfo_t *ksi, *next; 662 663 if (mask == NULL) 664 sigemptyset(&sp->sp_set); 665 else 666 sigminusset(mask, &sp->sp_set); 667 668 TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, next) { 669 if (mask == NULL || sigismember(mask, ksi->ksi_signo)) { 670 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 671 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 672 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 673 TAILQ_INSERT_TAIL(kq, ksi, ksi_list); 674 } 675 } 676 } 677 678 /* 679 * sigclearall: 680 * 681 * Clear all pending signals in the specified set from a process and 682 * its LWPs. 683 */ 684 void 685 sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq) 686 { 687 struct lwp *l; 688 689 KASSERT(mutex_owned(p->p_lock)); 690 691 sigclear(&p->p_sigpend, mask, kq); 692 693 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 694 sigclear(&l->l_sigpend, mask, kq); 695 } 696 } 697 698 /* 699 * sigispending: 700 * 701 * Return the first signal number if there are pending signals for the 702 * current LWP. May be called unlocked provided that LW_PENDSIG is set, 703 * and that the signal has been posted to the appopriate queue before 704 * LW_PENDSIG is set. 705 */ 706 int 707 sigispending(struct lwp *l, int signo) 708 { 709 struct proc *p = l->l_proc; 710 sigset_t tset; 711 712 membar_consumer(); 713 714 tset = l->l_sigpend.sp_set; 715 sigplusset(&p->p_sigpend.sp_set, &tset); 716 sigminusset(&p->p_sigctx.ps_sigignore, &tset); 717 sigminusset(&l->l_sigmask, &tset); 718 719 if (signo == 0) { 720 return firstsig(&tset); 721 } 722 return sigismember(&tset, signo) ? signo : 0; 723 } 724 725 void 726 getucontext(struct lwp *l, ucontext_t *ucp) 727 { 728 struct proc *p = l->l_proc; 729 730 KASSERT(mutex_owned(p->p_lock)); 731 732 ucp->uc_flags = 0; 733 ucp->uc_link = l->l_ctxlink; 734 ucp->uc_sigmask = l->l_sigmask; 735 ucp->uc_flags |= _UC_SIGMASK; 736 737 /* 738 * The (unsupplied) definition of the `current execution stack' 739 * in the System V Interface Definition appears to allow returning 740 * the main context stack. 741 */ 742 if ((l->l_sigstk.ss_flags & SS_ONSTACK) == 0) { 743 ucp->uc_stack.ss_sp = (void *)l->l_proc->p_stackbase; 744 ucp->uc_stack.ss_size = ctob(l->l_proc->p_vmspace->vm_ssize); 745 ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */ 746 } else { 747 /* Simply copy alternate signal execution stack. */ 748 ucp->uc_stack = l->l_sigstk; 749 } 750 ucp->uc_flags |= _UC_STACK; 751 mutex_exit(p->p_lock); 752 cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags); 753 mutex_enter(p->p_lock); 754 } 755 756 int 757 setucontext(struct lwp *l, const ucontext_t *ucp) 758 { 759 struct proc *p = l->l_proc; 760 int error; 761 762 KASSERT(mutex_owned(p->p_lock)); 763 764 if ((ucp->uc_flags & _UC_SIGMASK) != 0) { 765 error = sigprocmask1(l, SIG_SETMASK, &ucp->uc_sigmask, NULL); 766 if (error != 0) 767 return error; 768 } 769 770 mutex_exit(p->p_lock); 771 error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags); 772 mutex_enter(p->p_lock); 773 if (error != 0) 774 return (error); 775 776 l->l_ctxlink = ucp->uc_link; 777 778 /* 779 * If there was stack information, update whether or not we are 780 * still running on an alternate signal stack. 781 */ 782 if ((ucp->uc_flags & _UC_STACK) != 0) { 783 if (ucp->uc_stack.ss_flags & SS_ONSTACK) 784 l->l_sigstk.ss_flags |= SS_ONSTACK; 785 else 786 l->l_sigstk.ss_flags &= ~SS_ONSTACK; 787 } 788 789 return 0; 790 } 791 792 /* 793 * killpg1: common code for kill process group/broadcast kill. 794 */ 795 int 796 killpg1(struct lwp *l, ksiginfo_t *ksi, int pgid, int all) 797 { 798 struct proc *p, *cp; 799 kauth_cred_t pc; 800 struct pgrp *pgrp; 801 int nfound; 802 int signo = ksi->ksi_signo; 803 804 cp = l->l_proc; 805 pc = l->l_cred; 806 nfound = 0; 807 808 mutex_enter(proc_lock); 809 if (all) { 810 /* 811 * Broadcast. 812 */ 813 PROCLIST_FOREACH(p, &allproc) { 814 if (p->p_pid <= 1 || p == cp || 815 (p->p_flag & PK_SYSTEM) != 0) 816 continue; 817 mutex_enter(p->p_lock); 818 if (kauth_authorize_process(pc, 819 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signo), NULL, 820 NULL) == 0) { 821 nfound++; 822 if (signo) 823 kpsignal2(p, ksi); 824 } 825 mutex_exit(p->p_lock); 826 } 827 } else { 828 if (pgid == 0) 829 /* Zero pgid means send to my process group. */ 830 pgrp = cp->p_pgrp; 831 else { 832 pgrp = pgrp_find(pgid); 833 if (pgrp == NULL) 834 goto out; 835 } 836 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 837 if (p->p_pid <= 1 || p->p_flag & PK_SYSTEM) 838 continue; 839 mutex_enter(p->p_lock); 840 if (kauth_authorize_process(pc, KAUTH_PROCESS_SIGNAL, 841 p, KAUTH_ARG(signo), NULL, NULL) == 0) { 842 nfound++; 843 if (signo && P_ZOMBIE(p) == 0) 844 kpsignal2(p, ksi); 845 } 846 mutex_exit(p->p_lock); 847 } 848 } 849 out: 850 mutex_exit(proc_lock); 851 return nfound ? 0 : ESRCH; 852 } 853 854 /* 855 * Send a signal to a process group. If checktty is set, limit to members 856 * which have a controlling terminal. 857 */ 858 void 859 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 860 { 861 ksiginfo_t ksi; 862 863 KASSERT(!cpu_intr_p()); 864 KASSERT(mutex_owned(proc_lock)); 865 866 KSI_INIT_EMPTY(&ksi); 867 ksi.ksi_signo = sig; 868 kpgsignal(pgrp, &ksi, NULL, checkctty); 869 } 870 871 void 872 kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty) 873 { 874 struct proc *p; 875 876 KASSERT(!cpu_intr_p()); 877 KASSERT(mutex_owned(proc_lock)); 878 KASSERT(pgrp != NULL); 879 880 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) 881 if (checkctty == 0 || p->p_lflag & PL_CONTROLT) 882 kpsignal(p, ksi, data); 883 } 884 885 /* 886 * Send a signal caused by a trap to the current LWP. If it will be caught 887 * immediately, deliver it with correct code. Otherwise, post it normally. 888 */ 889 void 890 trapsignal(struct lwp *l, ksiginfo_t *ksi) 891 { 892 struct proc *p; 893 struct sigacts *ps; 894 int signo = ksi->ksi_signo; 895 sigset_t *mask; 896 897 KASSERT(KSI_TRAP_P(ksi)); 898 899 ksi->ksi_lid = l->l_lid; 900 p = l->l_proc; 901 902 KASSERT(!cpu_intr_p()); 903 mutex_enter(proc_lock); 904 mutex_enter(p->p_lock); 905 mask = &l->l_sigmask; 906 ps = p->p_sigacts; 907 908 if ((p->p_slflag & PSL_TRACED) == 0 && 909 sigismember(&p->p_sigctx.ps_sigcatch, signo) && 910 !sigismember(mask, signo)) { 911 mutex_exit(proc_lock); 912 l->l_ru.ru_nsignals++; 913 kpsendsig(l, ksi, mask); 914 mutex_exit(p->p_lock); 915 if (ktrpoint(KTR_PSIG)) { 916 ktrpsig(signo, SIGACTION_PS(ps, signo).sa_handler, 917 mask, ksi); 918 } 919 } else { 920 /* XXX for core dump/debugger */ 921 p->p_sigctx.ps_lwp = l->l_lid; 922 p->p_sigctx.ps_signo = ksi->ksi_signo; 923 p->p_sigctx.ps_code = ksi->ksi_trap; 924 kpsignal2(p, ksi); 925 mutex_exit(p->p_lock); 926 mutex_exit(proc_lock); 927 } 928 } 929 930 /* 931 * Fill in signal information and signal the parent for a child status change. 932 */ 933 void 934 child_psignal(struct proc *p, int mask) 935 { 936 ksiginfo_t ksi; 937 struct proc *q; 938 int xsig; 939 940 KASSERT(mutex_owned(proc_lock)); 941 KASSERT(mutex_owned(p->p_lock)); 942 943 xsig = p->p_xsig; 944 945 KSI_INIT(&ksi); 946 ksi.ksi_signo = SIGCHLD; 947 ksi.ksi_code = (xsig == SIGCONT ? CLD_CONTINUED : CLD_STOPPED); 948 ksi.ksi_pid = p->p_pid; 949 ksi.ksi_uid = kauth_cred_geteuid(p->p_cred); 950 ksi.ksi_status = xsig; 951 ksi.ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 952 ksi.ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 953 954 q = p->p_pptr; 955 956 mutex_exit(p->p_lock); 957 mutex_enter(q->p_lock); 958 959 if ((q->p_sflag & mask) == 0) 960 kpsignal2(q, &ksi); 961 962 mutex_exit(q->p_lock); 963 mutex_enter(p->p_lock); 964 } 965 966 void 967 psignal(struct proc *p, int signo) 968 { 969 ksiginfo_t ksi; 970 971 KASSERT(!cpu_intr_p()); 972 KASSERT(mutex_owned(proc_lock)); 973 974 KSI_INIT_EMPTY(&ksi); 975 ksi.ksi_signo = signo; 976 mutex_enter(p->p_lock); 977 kpsignal2(p, &ksi); 978 mutex_exit(p->p_lock); 979 } 980 981 void 982 kpsignal(struct proc *p, ksiginfo_t *ksi, void *data) 983 { 984 fdfile_t *ff; 985 file_t *fp; 986 fdtab_t *dt; 987 988 KASSERT(!cpu_intr_p()); 989 KASSERT(mutex_owned(proc_lock)); 990 991 if ((p->p_sflag & PS_WEXIT) == 0 && data) { 992 size_t fd; 993 filedesc_t *fdp = p->p_fd; 994 995 /* XXXSMP locking */ 996 ksi->ksi_fd = -1; 997 dt = fdp->fd_dt; 998 for (fd = 0; fd < dt->dt_nfiles; fd++) { 999 if ((ff = dt->dt_ff[fd]) == NULL) 1000 continue; 1001 if ((fp = ff->ff_file) == NULL) 1002 continue; 1003 if (fp->f_data == data) { 1004 ksi->ksi_fd = fd; 1005 break; 1006 } 1007 } 1008 } 1009 mutex_enter(p->p_lock); 1010 kpsignal2(p, ksi); 1011 mutex_exit(p->p_lock); 1012 } 1013 1014 /* 1015 * sigismasked: 1016 * 1017 * Returns true if signal is ignored or masked for the specified LWP. 1018 */ 1019 int 1020 sigismasked(struct lwp *l, int sig) 1021 { 1022 struct proc *p = l->l_proc; 1023 1024 return sigismember(&p->p_sigctx.ps_sigignore, sig) || 1025 sigismember(&l->l_sigmask, sig); 1026 } 1027 1028 /* 1029 * sigpost: 1030 * 1031 * Post a pending signal to an LWP. Returns non-zero if the LWP may 1032 * be able to take the signal. 1033 */ 1034 static int 1035 sigpost(struct lwp *l, sig_t action, int prop, int sig) 1036 { 1037 int rv, masked; 1038 struct proc *p = l->l_proc; 1039 1040 KASSERT(mutex_owned(p->p_lock)); 1041 1042 /* 1043 * If the LWP is on the way out, sigclear() will be busy draining all 1044 * pending signals. Don't give it more. 1045 */ 1046 if (l->l_refcnt == 0) 1047 return 0; 1048 1049 SDT_PROBE(proc, kernel, , signal__send, l, p, sig, 0, 0); 1050 1051 /* 1052 * Have the LWP check for signals. This ensures that even if no LWP 1053 * is found to take the signal immediately, it should be taken soon. 1054 */ 1055 lwp_lock(l); 1056 l->l_flag |= LW_PENDSIG; 1057 1058 /* 1059 * SIGCONT can be masked, but if LWP is stopped, it needs restart. 1060 * Note: SIGKILL and SIGSTOP cannot be masked. 1061 */ 1062 masked = sigismember(&l->l_sigmask, sig); 1063 if (masked && ((prop & SA_CONT) == 0 || l->l_stat != LSSTOP)) { 1064 lwp_unlock(l); 1065 return 0; 1066 } 1067 1068 /* 1069 * If killing the process, make it run fast. 1070 */ 1071 if (__predict_false((prop & SA_KILL) != 0) && 1072 action == SIG_DFL && l->l_priority < MAXPRI_USER) { 1073 KASSERT(l->l_class == SCHED_OTHER); 1074 lwp_changepri(l, MAXPRI_USER); 1075 } 1076 1077 /* 1078 * If the LWP is running or on a run queue, then we win. If it's 1079 * sleeping interruptably, wake it and make it take the signal. If 1080 * the sleep isn't interruptable, then the chances are it will get 1081 * to see the signal soon anyhow. If suspended, it can't take the 1082 * signal right now. If it's LWP private or for all LWPs, save it 1083 * for later; otherwise punt. 1084 */ 1085 rv = 0; 1086 1087 switch (l->l_stat) { 1088 case LSRUN: 1089 case LSONPROC: 1090 lwp_need_userret(l); 1091 rv = 1; 1092 break; 1093 1094 case LSSLEEP: 1095 if ((l->l_flag & LW_SINTR) != 0) { 1096 /* setrunnable() will release the lock. */ 1097 setrunnable(l); 1098 return 1; 1099 } 1100 break; 1101 1102 case LSSUSPENDED: 1103 if ((prop & SA_KILL) != 0 && (l->l_flag & LW_WCORE) != 0) { 1104 /* lwp_continue() will release the lock. */ 1105 lwp_continue(l); 1106 return 1; 1107 } 1108 break; 1109 1110 case LSSTOP: 1111 if ((prop & SA_STOP) != 0) 1112 break; 1113 1114 /* 1115 * If the LWP is stopped and we are sending a continue 1116 * signal, then start it again. 1117 */ 1118 if ((prop & SA_CONT) != 0) { 1119 if (l->l_wchan != NULL) { 1120 l->l_stat = LSSLEEP; 1121 p->p_nrlwps++; 1122 rv = 1; 1123 break; 1124 } 1125 /* setrunnable() will release the lock. */ 1126 setrunnable(l); 1127 return 1; 1128 } else if (l->l_wchan == NULL || (l->l_flag & LW_SINTR) != 0) { 1129 /* setrunnable() will release the lock. */ 1130 setrunnable(l); 1131 return 1; 1132 } 1133 break; 1134 1135 default: 1136 break; 1137 } 1138 1139 lwp_unlock(l); 1140 return rv; 1141 } 1142 1143 /* 1144 * Notify an LWP that it has a pending signal. 1145 */ 1146 void 1147 signotify(struct lwp *l) 1148 { 1149 KASSERT(lwp_locked(l, NULL)); 1150 1151 l->l_flag |= LW_PENDSIG; 1152 lwp_need_userret(l); 1153 } 1154 1155 /* 1156 * Find an LWP within process p that is waiting on signal ksi, and hand 1157 * it on. 1158 */ 1159 static int 1160 sigunwait(struct proc *p, const ksiginfo_t *ksi) 1161 { 1162 struct lwp *l; 1163 int signo; 1164 1165 KASSERT(mutex_owned(p->p_lock)); 1166 1167 signo = ksi->ksi_signo; 1168 1169 if (ksi->ksi_lid != 0) { 1170 /* 1171 * Signal came via _lwp_kill(). Find the LWP and see if 1172 * it's interested. 1173 */ 1174 if ((l = lwp_find(p, ksi->ksi_lid)) == NULL) 1175 return 0; 1176 if (l->l_sigwaited == NULL || 1177 !sigismember(&l->l_sigwaitset, signo)) 1178 return 0; 1179 } else { 1180 /* 1181 * Look for any LWP that may be interested. 1182 */ 1183 LIST_FOREACH(l, &p->p_sigwaiters, l_sigwaiter) { 1184 KASSERT(l->l_sigwaited != NULL); 1185 if (sigismember(&l->l_sigwaitset, signo)) 1186 break; 1187 } 1188 } 1189 1190 if (l != NULL) { 1191 l->l_sigwaited->ksi_info = ksi->ksi_info; 1192 l->l_sigwaited = NULL; 1193 LIST_REMOVE(l, l_sigwaiter); 1194 cv_signal(&l->l_sigcv); 1195 return 1; 1196 } 1197 1198 return 0; 1199 } 1200 1201 /* 1202 * Send the signal to the process. If the signal has an action, the action 1203 * is usually performed by the target process rather than the caller; we add 1204 * the signal to the set of pending signals for the process. 1205 * 1206 * Exceptions: 1207 * o When a stop signal is sent to a sleeping process that takes the 1208 * default action, the process is stopped without awakening it. 1209 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1210 * regardless of the signal action (eg, blocked or ignored). 1211 * 1212 * Other ignored signals are discarded immediately. 1213 */ 1214 int 1215 kpsignal2(struct proc *p, ksiginfo_t *ksi) 1216 { 1217 int prop, signo = ksi->ksi_signo; 1218 struct sigacts *sa; 1219 struct lwp *l = NULL; 1220 ksiginfo_t *kp; 1221 lwpid_t lid; 1222 sig_t action; 1223 bool toall; 1224 int error = 0; 1225 1226 KASSERT(!cpu_intr_p()); 1227 KASSERT(mutex_owned(proc_lock)); 1228 KASSERT(mutex_owned(p->p_lock)); 1229 KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); 1230 KASSERT(signo > 0 && signo < NSIG); 1231 1232 /* 1233 * If the process is being created by fork, is a zombie or is 1234 * exiting, then just drop the signal here and bail out. 1235 */ 1236 if (p->p_stat != SACTIVE && p->p_stat != SSTOP) 1237 return 0; 1238 1239 /* 1240 * Notify any interested parties of the signal. 1241 */ 1242 KNOTE(&p->p_klist, NOTE_SIGNAL | signo); 1243 1244 /* 1245 * Some signals including SIGKILL must act on the entire process. 1246 */ 1247 kp = NULL; 1248 prop = sigprop[signo]; 1249 toall = ((prop & SA_TOALL) != 0); 1250 lid = toall ? 0 : ksi->ksi_lid; 1251 1252 /* 1253 * If proc is traced, always give parent a chance. 1254 */ 1255 if (p->p_slflag & PSL_TRACED) { 1256 action = SIG_DFL; 1257 1258 if (lid == 0) { 1259 /* 1260 * If the process is being traced and the signal 1261 * is being caught, make sure to save any ksiginfo. 1262 */ 1263 if ((kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1264 goto discard; 1265 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1266 goto out; 1267 } 1268 } else { 1269 /* 1270 * If the signal was the result of a trap and is not being 1271 * caught, then reset it to default action so that the 1272 * process dumps core immediately. 1273 */ 1274 if (KSI_TRAP_P(ksi)) { 1275 sa = p->p_sigacts; 1276 mutex_enter(&sa->sa_mutex); 1277 if (!sigismember(&p->p_sigctx.ps_sigcatch, signo)) { 1278 sigdelset(&p->p_sigctx.ps_sigignore, signo); 1279 SIGACTION(p, signo).sa_handler = SIG_DFL; 1280 } 1281 mutex_exit(&sa->sa_mutex); 1282 } 1283 1284 /* 1285 * If the signal is being ignored, then drop it. Note: we 1286 * don't set SIGCONT in ps_sigignore, and if it is set to 1287 * SIG_IGN, action will be SIG_DFL here. 1288 */ 1289 if (sigismember(&p->p_sigctx.ps_sigignore, signo)) 1290 goto discard; 1291 1292 else if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) 1293 action = SIG_CATCH; 1294 else { 1295 action = SIG_DFL; 1296 1297 /* 1298 * If sending a tty stop signal to a member of an 1299 * orphaned process group, discard the signal here if 1300 * the action is default; don't stop the process below 1301 * if sleeping, and don't clear any pending SIGCONT. 1302 */ 1303 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0) 1304 goto discard; 1305 1306 if (prop & SA_KILL && p->p_nice > NZERO) 1307 p->p_nice = NZERO; 1308 } 1309 } 1310 1311 /* 1312 * If stopping or continuing a process, discard any pending 1313 * signals that would do the inverse. 1314 */ 1315 if ((prop & (SA_CONT | SA_STOP)) != 0) { 1316 ksiginfoq_t kq; 1317 1318 ksiginfo_queue_init(&kq); 1319 if ((prop & SA_CONT) != 0) 1320 sigclear(&p->p_sigpend, &stopsigmask, &kq); 1321 if ((prop & SA_STOP) != 0) 1322 sigclear(&p->p_sigpend, &contsigmask, &kq); 1323 ksiginfo_queue_drain(&kq); /* XXXSMP */ 1324 } 1325 1326 /* 1327 * If the signal doesn't have SA_CANTMASK (no override for SIGKILL, 1328 * please!), check if any LWPs are waiting on it. If yes, pass on 1329 * the signal info. The signal won't be processed further here. 1330 */ 1331 if ((prop & SA_CANTMASK) == 0 && !LIST_EMPTY(&p->p_sigwaiters) && 1332 p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0 && 1333 sigunwait(p, ksi)) 1334 goto discard; 1335 1336 /* 1337 * XXXSMP Should be allocated by the caller, we're holding locks 1338 * here. 1339 */ 1340 if (kp == NULL && (kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1341 goto discard; 1342 1343 /* 1344 * LWP private signals are easy - just find the LWP and post 1345 * the signal to it. 1346 */ 1347 if (lid != 0) { 1348 l = lwp_find(p, lid); 1349 if (l != NULL) { 1350 if ((error = sigput(&l->l_sigpend, p, kp)) != 0) 1351 goto out; 1352 membar_producer(); 1353 (void)sigpost(l, action, prop, kp->ksi_signo); 1354 } 1355 goto out; 1356 } 1357 1358 /* 1359 * Some signals go to all LWPs, even if posted with _lwp_kill() 1360 * or for an SA process. 1361 */ 1362 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1363 if ((p->p_slflag & PSL_TRACED) != 0) 1364 goto deliver; 1365 1366 /* 1367 * If SIGCONT is default (or ignored) and process is 1368 * asleep, we are finished; the process should not 1369 * be awakened. 1370 */ 1371 if ((prop & SA_CONT) != 0 && action == SIG_DFL) 1372 goto out; 1373 } else { 1374 /* 1375 * Process is stopped or stopping. 1376 * - If traced, then no action is needed, unless killing. 1377 * - Run the process only if sending SIGCONT or SIGKILL. 1378 */ 1379 if ((p->p_slflag & PSL_TRACED) != 0 && signo != SIGKILL) { 1380 goto out; 1381 } 1382 if ((prop & SA_CONT) != 0 || signo == SIGKILL) { 1383 /* 1384 * Re-adjust p_nstopchild if the process was 1385 * stopped but not yet collected by its parent. 1386 */ 1387 if (p->p_stat == SSTOP && !p->p_waited) 1388 p->p_pptr->p_nstopchild--; 1389 p->p_stat = SACTIVE; 1390 p->p_sflag &= ~PS_STOPPING; 1391 if (p->p_slflag & PSL_TRACED) { 1392 KASSERT(signo == SIGKILL); 1393 goto deliver; 1394 } 1395 /* 1396 * Do not make signal pending if SIGCONT is default. 1397 * 1398 * If the process catches SIGCONT, let it handle the 1399 * signal itself (if waiting on event - process runs, 1400 * otherwise continues sleeping). 1401 */ 1402 if ((prop & SA_CONT) != 0) { 1403 p->p_xsig = SIGCONT; 1404 p->p_sflag |= PS_CONTINUED; 1405 child_psignal(p, 0); 1406 if (action == SIG_DFL) { 1407 KASSERT(signo != SIGKILL); 1408 goto deliver; 1409 } 1410 } 1411 } else if ((prop & SA_STOP) != 0) { 1412 /* 1413 * Already stopped, don't need to stop again. 1414 * (If we did the shell could get confused.) 1415 */ 1416 goto out; 1417 } 1418 } 1419 /* 1420 * Make signal pending. 1421 */ 1422 KASSERT((p->p_slflag & PSL_TRACED) == 0); 1423 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1424 goto out; 1425 deliver: 1426 /* 1427 * Before we set LW_PENDSIG on any LWP, ensure that the signal is 1428 * visible on the per process list (for sigispending()). This 1429 * is unlikely to be needed in practice, but... 1430 */ 1431 membar_producer(); 1432 1433 /* 1434 * Try to find an LWP that can take the signal. 1435 */ 1436 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1437 if (sigpost(l, action, prop, kp->ksi_signo) && !toall) 1438 break; 1439 } 1440 signo = -1; 1441 out: 1442 /* 1443 * If the ksiginfo wasn't used, then bin it. XXXSMP freeing memory 1444 * with locks held. The caller should take care of this. 1445 */ 1446 ksiginfo_free(kp); 1447 if (signo == -1) 1448 return error; 1449 discard: 1450 SDT_PROBE(proc, kernel, , signal__discard, l, p, signo, 0, 0); 1451 return error; 1452 } 1453 1454 void 1455 kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask) 1456 { 1457 struct proc *p = l->l_proc; 1458 1459 KASSERT(mutex_owned(p->p_lock)); 1460 (*p->p_emul->e_sendsig)(ksi, mask); 1461 } 1462 1463 /* 1464 * Stop any LWPs sleeping interruptably. 1465 */ 1466 static void 1467 proc_stop_lwps(struct proc *p) 1468 { 1469 struct lwp *l; 1470 1471 KASSERT(mutex_owned(p->p_lock)); 1472 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1473 1474 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1475 lwp_lock(l); 1476 if (l->l_stat == LSSLEEP && (l->l_flag & LW_SINTR) != 0) { 1477 l->l_stat = LSSTOP; 1478 p->p_nrlwps--; 1479 } 1480 lwp_unlock(l); 1481 } 1482 } 1483 1484 /* 1485 * Finish stopping of a process. Mark it stopped and notify the parent. 1486 * 1487 * Drop p_lock briefly if PS_NOTIFYSTOP is set and ppsig is true. 1488 */ 1489 static void 1490 proc_stop_done(struct proc *p, bool ppsig, int ppmask) 1491 { 1492 1493 KASSERT(mutex_owned(proc_lock)); 1494 KASSERT(mutex_owned(p->p_lock)); 1495 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1496 KASSERT(p->p_nrlwps == 0 || (p->p_nrlwps == 1 && p == curproc)); 1497 1498 p->p_sflag &= ~PS_STOPPING; 1499 p->p_stat = SSTOP; 1500 p->p_waited = 0; 1501 p->p_pptr->p_nstopchild++; 1502 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 1503 if (ppsig) { 1504 /* child_psignal drops p_lock briefly. */ 1505 child_psignal(p, ppmask); 1506 } 1507 cv_broadcast(&p->p_pptr->p_waitcv); 1508 } 1509 } 1510 1511 /* 1512 * Stop the current process and switch away when being stopped or traced. 1513 */ 1514 static void 1515 sigswitch(bool ppsig, int ppmask, int signo) 1516 { 1517 struct lwp *l = curlwp; 1518 struct proc *p = l->l_proc; 1519 int biglocks; 1520 1521 KASSERT(mutex_owned(p->p_lock)); 1522 KASSERT(l->l_stat == LSONPROC); 1523 KASSERT(p->p_nrlwps > 0); 1524 1525 /* 1526 * On entry we know that the process needs to stop. If it's 1527 * the result of a 'sideways' stop signal that has been sourced 1528 * through issignal(), then stop other LWPs in the process too. 1529 */ 1530 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1531 KASSERT(signo != 0); 1532 proc_stop(p, 1, signo); 1533 KASSERT(p->p_nrlwps > 0); 1534 } 1535 1536 /* 1537 * If we are the last live LWP, and the stop was a result of 1538 * a new signal, then signal the parent. 1539 */ 1540 if ((p->p_sflag & PS_STOPPING) != 0) { 1541 if (!mutex_tryenter(proc_lock)) { 1542 mutex_exit(p->p_lock); 1543 mutex_enter(proc_lock); 1544 mutex_enter(p->p_lock); 1545 } 1546 1547 if (p->p_nrlwps == 1 && (p->p_sflag & PS_STOPPING) != 0) { 1548 /* 1549 * Note that proc_stop_done() can drop 1550 * p->p_lock briefly. 1551 */ 1552 proc_stop_done(p, ppsig, ppmask); 1553 } 1554 1555 mutex_exit(proc_lock); 1556 } 1557 1558 /* 1559 * Unlock and switch away. 1560 */ 1561 KERNEL_UNLOCK_ALL(l, &biglocks); 1562 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1563 p->p_nrlwps--; 1564 lwp_lock(l); 1565 KASSERT(l->l_stat == LSONPROC || l->l_stat == LSSLEEP); 1566 l->l_stat = LSSTOP; 1567 lwp_unlock(l); 1568 } 1569 1570 mutex_exit(p->p_lock); 1571 lwp_lock(l); 1572 mi_switch(l); 1573 KERNEL_LOCK(biglocks, l); 1574 mutex_enter(p->p_lock); 1575 } 1576 1577 /* 1578 * Check for a signal from the debugger. 1579 */ 1580 static int 1581 sigchecktrace(void) 1582 { 1583 struct lwp *l = curlwp; 1584 struct proc *p = l->l_proc; 1585 int signo; 1586 1587 KASSERT(mutex_owned(p->p_lock)); 1588 1589 /* If there's a pending SIGKILL, process it immediately. */ 1590 if (sigismember(&p->p_sigpend.sp_set, SIGKILL)) 1591 return 0; 1592 1593 /* 1594 * If we are no longer being traced, or the parent didn't 1595 * give us a signal, or we're stopping, look for more signals. 1596 */ 1597 if ((p->p_slflag & PSL_TRACED) == 0 || p->p_xsig == 0 || 1598 (p->p_sflag & PS_STOPPING) != 0) 1599 return 0; 1600 1601 /* 1602 * If the new signal is being masked, look for other signals. 1603 * `p->p_sigctx.ps_siglist |= mask' is done in setrunnable(). 1604 */ 1605 signo = p->p_xsig; 1606 p->p_xsig = 0; 1607 if (sigismember(&l->l_sigmask, signo)) { 1608 signo = 0; 1609 } 1610 return signo; 1611 } 1612 1613 /* 1614 * If the current process has received a signal (should be caught or cause 1615 * termination, should interrupt current syscall), return the signal number. 1616 * 1617 * Stop signals with default action are processed immediately, then cleared; 1618 * they aren't returned. This is checked after each entry to the system for 1619 * a syscall or trap. 1620 * 1621 * We will also return -1 if the process is exiting and the current LWP must 1622 * follow suit. 1623 */ 1624 int 1625 issignal(struct lwp *l) 1626 { 1627 struct proc *p; 1628 int signo, prop; 1629 sigpend_t *sp; 1630 sigset_t ss; 1631 1632 p = l->l_proc; 1633 sp = NULL; 1634 signo = 0; 1635 1636 KASSERT(p == curproc); 1637 KASSERT(mutex_owned(p->p_lock)); 1638 1639 for (;;) { 1640 /* Discard any signals that we have decided not to take. */ 1641 if (signo != 0) { 1642 (void)sigget(sp, NULL, signo, NULL); 1643 } 1644 1645 /* 1646 * If the process is stopped/stopping, then stop ourselves 1647 * now that we're on the kernel/userspace boundary. When 1648 * we awaken, check for a signal from the debugger. 1649 */ 1650 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1651 sigswitch(true, PS_NOCLDSTOP, 0); 1652 signo = sigchecktrace(); 1653 } else 1654 signo = 0; 1655 1656 /* Signals from the debugger are "out of band". */ 1657 sp = NULL; 1658 1659 /* 1660 * If the debugger didn't provide a signal, find a pending 1661 * signal from our set. Check per-LWP signals first, and 1662 * then per-process. 1663 */ 1664 if (signo == 0) { 1665 sp = &l->l_sigpend; 1666 ss = sp->sp_set; 1667 if ((p->p_lflag & PL_PPWAIT) != 0) 1668 sigminusset(&stopsigmask, &ss); 1669 sigminusset(&l->l_sigmask, &ss); 1670 1671 if ((signo = firstsig(&ss)) == 0) { 1672 sp = &p->p_sigpend; 1673 ss = sp->sp_set; 1674 if ((p->p_lflag & PL_PPWAIT) != 0) 1675 sigminusset(&stopsigmask, &ss); 1676 sigminusset(&l->l_sigmask, &ss); 1677 1678 if ((signo = firstsig(&ss)) == 0) { 1679 /* 1680 * No signal pending - clear the 1681 * indicator and bail out. 1682 */ 1683 lwp_lock(l); 1684 l->l_flag &= ~LW_PENDSIG; 1685 lwp_unlock(l); 1686 sp = NULL; 1687 break; 1688 } 1689 } 1690 } 1691 1692 /* 1693 * We should see pending but ignored signals only if 1694 * we are being traced. 1695 */ 1696 if (sigismember(&p->p_sigctx.ps_sigignore, signo) && 1697 (p->p_slflag & PSL_TRACED) == 0) { 1698 /* Discard the signal. */ 1699 continue; 1700 } 1701 1702 /* 1703 * If traced, always stop, and stay stopped until released 1704 * by the debugger. If the our parent process is waiting 1705 * for us, don't hang as we could deadlock. 1706 */ 1707 if ((p->p_slflag & PSL_TRACED) != 0 && 1708 (p->p_lflag & PL_PPWAIT) == 0 && signo != SIGKILL) { 1709 /* 1710 * Take the signal, but don't remove it from the 1711 * siginfo queue, because the debugger can send 1712 * it later. 1713 */ 1714 if (sp) 1715 sigdelset(&sp->sp_set, signo); 1716 p->p_xsig = signo; 1717 1718 /* Emulation-specific handling of signal trace */ 1719 if (p->p_emul->e_tracesig == NULL || 1720 (*p->p_emul->e_tracesig)(p, signo) == 0) 1721 sigswitch(!(p->p_slflag & PSL_FSTRACE), 0, 1722 signo); 1723 1724 /* Check for a signal from the debugger. */ 1725 if ((signo = sigchecktrace()) == 0) 1726 continue; 1727 1728 /* Signals from the debugger are "out of band". */ 1729 sp = NULL; 1730 } 1731 1732 prop = sigprop[signo]; 1733 1734 /* 1735 * Decide whether the signal should be returned. 1736 */ 1737 switch ((long)SIGACTION(p, signo).sa_handler) { 1738 case (long)SIG_DFL: 1739 /* 1740 * Don't take default actions on system processes. 1741 */ 1742 if (p->p_pid <= 1) { 1743 #ifdef DIAGNOSTIC 1744 /* 1745 * Are you sure you want to ignore SIGSEGV 1746 * in init? XXX 1747 */ 1748 printf_nolog("Process (pid %d) got sig %d\n", 1749 p->p_pid, signo); 1750 #endif 1751 continue; 1752 } 1753 1754 /* 1755 * If there is a pending stop signal to process with 1756 * default action, stop here, then clear the signal. 1757 * However, if process is member of an orphaned 1758 * process group, ignore tty stop signals. 1759 */ 1760 if (prop & SA_STOP) { 1761 /* 1762 * XXX Don't hold proc_lock for p_lflag, 1763 * but it's not a big deal. 1764 */ 1765 if (p->p_slflag & PSL_TRACED || 1766 ((p->p_lflag & PL_ORPHANPG) != 0 && 1767 prop & SA_TTYSTOP)) { 1768 /* Ignore the signal. */ 1769 continue; 1770 } 1771 /* Take the signal. */ 1772 (void)sigget(sp, NULL, signo, NULL); 1773 p->p_xsig = signo; 1774 p->p_sflag &= ~PS_CONTINUED; 1775 signo = 0; 1776 sigswitch(true, PS_NOCLDSTOP, p->p_xsig); 1777 } else if (prop & SA_IGNORE) { 1778 /* 1779 * Except for SIGCONT, shouldn't get here. 1780 * Default action is to ignore; drop it. 1781 */ 1782 continue; 1783 } 1784 break; 1785 1786 case (long)SIG_IGN: 1787 #ifdef DEBUG_ISSIGNAL 1788 /* 1789 * Masking above should prevent us ever trying 1790 * to take action on an ignored signal other 1791 * than SIGCONT, unless process is traced. 1792 */ 1793 if ((prop & SA_CONT) == 0 && 1794 (p->p_slflag & PSL_TRACED) == 0) 1795 printf_nolog("issignal\n"); 1796 #endif 1797 continue; 1798 1799 default: 1800 /* 1801 * This signal has an action, let postsig() process 1802 * it. 1803 */ 1804 break; 1805 } 1806 1807 break; 1808 } 1809 1810 l->l_sigpendset = sp; 1811 return signo; 1812 } 1813 1814 /* 1815 * Take the action for the specified signal 1816 * from the current set of pending signals. 1817 */ 1818 void 1819 postsig(int signo) 1820 { 1821 struct lwp *l; 1822 struct proc *p; 1823 struct sigacts *ps; 1824 sig_t action; 1825 sigset_t *returnmask; 1826 ksiginfo_t ksi; 1827 1828 l = curlwp; 1829 p = l->l_proc; 1830 ps = p->p_sigacts; 1831 1832 KASSERT(mutex_owned(p->p_lock)); 1833 KASSERT(signo > 0); 1834 1835 /* 1836 * Set the new mask value and also defer further occurrences of this 1837 * signal. 1838 * 1839 * Special case: user has done a sigsuspend. Here the current mask is 1840 * not of interest, but rather the mask from before the sigsuspend is 1841 * what we want restored after the signal processing is completed. 1842 */ 1843 if (l->l_sigrestore) { 1844 returnmask = &l->l_sigoldmask; 1845 l->l_sigrestore = 0; 1846 } else 1847 returnmask = &l->l_sigmask; 1848 1849 /* 1850 * Commit to taking the signal before releasing the mutex. 1851 */ 1852 action = SIGACTION_PS(ps, signo).sa_handler; 1853 l->l_ru.ru_nsignals++; 1854 if (l->l_sigpendset == NULL) { 1855 /* From the debugger */ 1856 if (!siggetinfo(&l->l_sigpend, &ksi, signo)) 1857 (void)siggetinfo(&p->p_sigpend, &ksi, signo); 1858 } else 1859 sigget(l->l_sigpendset, &ksi, signo, NULL); 1860 1861 if (ktrpoint(KTR_PSIG)) { 1862 mutex_exit(p->p_lock); 1863 ktrpsig(signo, action, returnmask, &ksi); 1864 mutex_enter(p->p_lock); 1865 } 1866 1867 SDT_PROBE(proc, kernel, , signal__handle, signo, &ksi, action, 0, 0); 1868 1869 if (action == SIG_DFL) { 1870 /* 1871 * Default action, where the default is to kill 1872 * the process. (Other cases were ignored above.) 1873 */ 1874 sigexit(l, signo); 1875 return; 1876 } 1877 1878 /* 1879 * If we get here, the signal must be caught. 1880 */ 1881 #ifdef DIAGNOSTIC 1882 if (action == SIG_IGN || sigismember(&l->l_sigmask, signo)) 1883 panic("postsig action"); 1884 #endif 1885 1886 kpsendsig(l, &ksi, returnmask); 1887 } 1888 1889 /* 1890 * sendsig: 1891 * 1892 * Default signal delivery method for NetBSD. 1893 */ 1894 void 1895 sendsig(const struct ksiginfo *ksi, const sigset_t *mask) 1896 { 1897 struct sigacts *sa; 1898 int sig; 1899 1900 sig = ksi->ksi_signo; 1901 sa = curproc->p_sigacts; 1902 1903 switch (sa->sa_sigdesc[sig].sd_vers) { 1904 case 0: 1905 case 1: 1906 /* Compat for 1.6 and earlier. */ 1907 if (sendsig_sigcontext_vec == NULL) { 1908 break; 1909 } 1910 (*sendsig_sigcontext_vec)(ksi, mask); 1911 return; 1912 case 2: 1913 case 3: 1914 sendsig_siginfo(ksi, mask); 1915 return; 1916 default: 1917 break; 1918 } 1919 1920 printf("sendsig: bad version %d\n", sa->sa_sigdesc[sig].sd_vers); 1921 sigexit(curlwp, SIGILL); 1922 } 1923 1924 /* 1925 * sendsig_reset: 1926 * 1927 * Reset the signal action. Called from emulation specific sendsig() 1928 * before unlocking to deliver the signal. 1929 */ 1930 void 1931 sendsig_reset(struct lwp *l, int signo) 1932 { 1933 struct proc *p = l->l_proc; 1934 struct sigacts *ps = p->p_sigacts; 1935 1936 KASSERT(mutex_owned(p->p_lock)); 1937 1938 p->p_sigctx.ps_lwp = 0; 1939 p->p_sigctx.ps_code = 0; 1940 p->p_sigctx.ps_signo = 0; 1941 1942 mutex_enter(&ps->sa_mutex); 1943 sigplusset(&SIGACTION_PS(ps, signo).sa_mask, &l->l_sigmask); 1944 if (SIGACTION_PS(ps, signo).sa_flags & SA_RESETHAND) { 1945 sigdelset(&p->p_sigctx.ps_sigcatch, signo); 1946 if (signo != SIGCONT && sigprop[signo] & SA_IGNORE) 1947 sigaddset(&p->p_sigctx.ps_sigignore, signo); 1948 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 1949 } 1950 mutex_exit(&ps->sa_mutex); 1951 } 1952 1953 /* 1954 * Kill the current process for stated reason. 1955 */ 1956 void 1957 killproc(struct proc *p, const char *why) 1958 { 1959 1960 KASSERT(mutex_owned(proc_lock)); 1961 1962 log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why); 1963 uprintf_locked("sorry, pid %d was killed: %s\n", p->p_pid, why); 1964 psignal(p, SIGKILL); 1965 } 1966 1967 /* 1968 * Force the current process to exit with the specified signal, dumping core 1969 * if appropriate. We bypass the normal tests for masked and caught 1970 * signals, allowing unrecoverable failures to terminate the process without 1971 * changing signal state. Mark the accounting record with the signal 1972 * termination. If dumping core, save the signal number for the debugger. 1973 * Calls exit and does not return. 1974 */ 1975 void 1976 sigexit(struct lwp *l, int signo) 1977 { 1978 int exitsig, error, docore; 1979 struct proc *p; 1980 struct lwp *t; 1981 1982 p = l->l_proc; 1983 1984 KASSERT(mutex_owned(p->p_lock)); 1985 KERNEL_UNLOCK_ALL(l, NULL); 1986 1987 /* 1988 * Don't permit coredump() multiple times in the same process. 1989 * Call back into sigexit, where we will be suspended until 1990 * the deed is done. Note that this is a recursive call, but 1991 * LW_WCORE will prevent us from coming back this way. 1992 */ 1993 if ((p->p_sflag & PS_WCORE) != 0) { 1994 lwp_lock(l); 1995 l->l_flag |= (LW_WCORE | LW_WEXIT | LW_WSUSPEND); 1996 lwp_unlock(l); 1997 mutex_exit(p->p_lock); 1998 lwp_userret(l); 1999 panic("sigexit 1"); 2000 /* NOTREACHED */ 2001 } 2002 2003 /* If process is already on the way out, then bail now. */ 2004 if ((p->p_sflag & PS_WEXIT) != 0) { 2005 mutex_exit(p->p_lock); 2006 lwp_exit(l); 2007 panic("sigexit 2"); 2008 /* NOTREACHED */ 2009 } 2010 2011 /* 2012 * Prepare all other LWPs for exit. If dumping core, suspend them 2013 * so that their registers are available long enough to be dumped. 2014 */ 2015 if ((docore = (sigprop[signo] & SA_CORE)) != 0) { 2016 p->p_sflag |= PS_WCORE; 2017 for (;;) { 2018 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 2019 lwp_lock(t); 2020 if (t == l) { 2021 t->l_flag &= ~LW_WSUSPEND; 2022 lwp_unlock(t); 2023 continue; 2024 } 2025 t->l_flag |= (LW_WCORE | LW_WEXIT); 2026 lwp_suspend(l, t); 2027 } 2028 2029 if (p->p_nrlwps == 1) 2030 break; 2031 2032 /* 2033 * Kick any LWPs sitting in lwp_wait1(), and wait 2034 * for everyone else to stop before proceeding. 2035 */ 2036 p->p_nlwpwait++; 2037 cv_broadcast(&p->p_lwpcv); 2038 cv_wait(&p->p_lwpcv, p->p_lock); 2039 p->p_nlwpwait--; 2040 } 2041 } 2042 2043 exitsig = signo; 2044 p->p_acflag |= AXSIG; 2045 p->p_sigctx.ps_signo = signo; 2046 2047 if (docore) { 2048 mutex_exit(p->p_lock); 2049 error = (*coredump_vec)(l, NULL); 2050 2051 if (kern_logsigexit) { 2052 int uid = l->l_cred ? 2053 (int)kauth_cred_geteuid(l->l_cred) : -1; 2054 2055 if (error) 2056 log(LOG_INFO, lognocoredump, p->p_pid, 2057 p->p_comm, uid, signo, error); 2058 else 2059 log(LOG_INFO, logcoredump, p->p_pid, 2060 p->p_comm, uid, signo); 2061 } 2062 2063 #ifdef PAX_SEGVGUARD 2064 pax_segvguard(l, p->p_textvp, p->p_comm, true); 2065 #endif /* PAX_SEGVGUARD */ 2066 /* Acquire the sched state mutex. exit1() will release it. */ 2067 mutex_enter(p->p_lock); 2068 if (error == 0) 2069 p->p_sflag |= PS_COREDUMP; 2070 } 2071 2072 /* No longer dumping core. */ 2073 p->p_sflag &= ~PS_WCORE; 2074 2075 exit1(l, 0, exitsig); 2076 /* NOTREACHED */ 2077 } 2078 2079 /* 2080 * Put process 'p' into the stopped state and optionally, notify the parent. 2081 */ 2082 void 2083 proc_stop(struct proc *p, int notify, int signo) 2084 { 2085 struct lwp *l; 2086 2087 KASSERT(mutex_owned(p->p_lock)); 2088 2089 /* 2090 * First off, set the stopping indicator and bring all sleeping 2091 * LWPs to a halt so they are included in p->p_nrlwps. We musn't 2092 * unlock between here and the p->p_nrlwps check below. 2093 */ 2094 p->p_sflag |= PS_STOPPING; 2095 if (notify) 2096 p->p_sflag |= PS_NOTIFYSTOP; 2097 else 2098 p->p_sflag &= ~PS_NOTIFYSTOP; 2099 membar_producer(); 2100 2101 proc_stop_lwps(p); 2102 2103 /* 2104 * If there are no LWPs available to take the signal, then we 2105 * signal the parent process immediately. Otherwise, the last 2106 * LWP to stop will take care of it. 2107 */ 2108 2109 if (p->p_nrlwps == 0) { 2110 proc_stop_done(p, true, PS_NOCLDSTOP); 2111 } else { 2112 /* 2113 * Have the remaining LWPs come to a halt, and trigger 2114 * proc_stop_callout() to ensure that they do. 2115 */ 2116 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2117 sigpost(l, SIG_DFL, SA_STOP, signo); 2118 } 2119 callout_schedule(&proc_stop_ch, 1); 2120 } 2121 } 2122 2123 /* 2124 * When stopping a process, we do not immediatly set sleeping LWPs stopped, 2125 * but wait for them to come to a halt at the kernel-user boundary. This is 2126 * to allow LWPs to release any locks that they may hold before stopping. 2127 * 2128 * Non-interruptable sleeps can be long, and there is the potential for an 2129 * LWP to begin sleeping interruptably soon after the process has been set 2130 * stopping (PS_STOPPING). These LWPs will not notice that the process is 2131 * stopping, and so complete halt of the process and the return of status 2132 * information to the parent could be delayed indefinitely. 2133 * 2134 * To handle this race, proc_stop_callout() runs once per tick while there 2135 * are stopping processes in the system. It sets LWPs that are sleeping 2136 * interruptably into the LSSTOP state. 2137 * 2138 * Note that we are not concerned about keeping all LWPs stopped while the 2139 * process is stopped: stopped LWPs can awaken briefly to handle signals. 2140 * What we do need to ensure is that all LWPs in a stopping process have 2141 * stopped at least once, so that notification can be sent to the parent 2142 * process. 2143 */ 2144 static void 2145 proc_stop_callout(void *cookie) 2146 { 2147 bool more, restart; 2148 struct proc *p; 2149 2150 (void)cookie; 2151 2152 do { 2153 restart = false; 2154 more = false; 2155 2156 mutex_enter(proc_lock); 2157 PROCLIST_FOREACH(p, &allproc) { 2158 mutex_enter(p->p_lock); 2159 2160 if ((p->p_sflag & PS_STOPPING) == 0) { 2161 mutex_exit(p->p_lock); 2162 continue; 2163 } 2164 2165 /* Stop any LWPs sleeping interruptably. */ 2166 proc_stop_lwps(p); 2167 if (p->p_nrlwps == 0) { 2168 /* 2169 * We brought the process to a halt. 2170 * Mark it as stopped and notify the 2171 * parent. 2172 */ 2173 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 2174 /* 2175 * Note that proc_stop_done() will 2176 * drop p->p_lock briefly. 2177 * Arrange to restart and check 2178 * all processes again. 2179 */ 2180 restart = true; 2181 } 2182 proc_stop_done(p, true, PS_NOCLDSTOP); 2183 } else 2184 more = true; 2185 2186 mutex_exit(p->p_lock); 2187 if (restart) 2188 break; 2189 } 2190 mutex_exit(proc_lock); 2191 } while (restart); 2192 2193 /* 2194 * If we noted processes that are stopping but still have 2195 * running LWPs, then arrange to check again in 1 tick. 2196 */ 2197 if (more) 2198 callout_schedule(&proc_stop_ch, 1); 2199 } 2200 2201 /* 2202 * Given a process in state SSTOP, set the state back to SACTIVE and 2203 * move LSSTOP'd LWPs to LSSLEEP or make them runnable. 2204 */ 2205 void 2206 proc_unstop(struct proc *p) 2207 { 2208 struct lwp *l; 2209 int sig; 2210 2211 KASSERT(mutex_owned(proc_lock)); 2212 KASSERT(mutex_owned(p->p_lock)); 2213 2214 p->p_stat = SACTIVE; 2215 p->p_sflag &= ~PS_STOPPING; 2216 sig = p->p_xsig; 2217 2218 if (!p->p_waited) 2219 p->p_pptr->p_nstopchild--; 2220 2221 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2222 lwp_lock(l); 2223 if (l->l_stat != LSSTOP) { 2224 lwp_unlock(l); 2225 continue; 2226 } 2227 if (l->l_wchan == NULL) { 2228 setrunnable(l); 2229 continue; 2230 } 2231 if (sig && (l->l_flag & LW_SINTR) != 0) { 2232 setrunnable(l); 2233 sig = 0; 2234 } else { 2235 l->l_stat = LSSLEEP; 2236 p->p_nrlwps++; 2237 lwp_unlock(l); 2238 } 2239 } 2240 } 2241 2242 static int 2243 filt_sigattach(struct knote *kn) 2244 { 2245 struct proc *p = curproc; 2246 2247 kn->kn_obj = p; 2248 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2249 2250 mutex_enter(p->p_lock); 2251 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2252 mutex_exit(p->p_lock); 2253 2254 return 0; 2255 } 2256 2257 static void 2258 filt_sigdetach(struct knote *kn) 2259 { 2260 struct proc *p = kn->kn_obj; 2261 2262 mutex_enter(p->p_lock); 2263 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2264 mutex_exit(p->p_lock); 2265 } 2266 2267 /* 2268 * Signal knotes are shared with proc knotes, so we apply a mask to 2269 * the hint in order to differentiate them from process hints. This 2270 * could be avoided by using a signal-specific knote list, but probably 2271 * isn't worth the trouble. 2272 */ 2273 static int 2274 filt_signal(struct knote *kn, long hint) 2275 { 2276 2277 if (hint & NOTE_SIGNAL) { 2278 hint &= ~NOTE_SIGNAL; 2279 2280 if (kn->kn_id == hint) 2281 kn->kn_data++; 2282 } 2283 return (kn->kn_data != 0); 2284 } 2285 2286 const struct filterops sig_filtops = { 2287 0, filt_sigattach, filt_sigdetach, filt_signal 2288 }; 2289
Indexes created Fri Sep 26 20:09:58 GMT 2025