kern_sig.c revision 1.338
1 /* $NetBSD: kern_sig.c,v 1.338 2017/10/25 08:12:39 maya 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 1.338 2017/10/25 08:12:39 maya 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 static sigset_t stopsigmask __cacheline_aligned; 117 sigset_t sigcantmask __cacheline_aligned; 118 119 static void ksiginfo_exechook(struct proc *, void *); 120 static void proc_stop(struct proc *, int); 121 static void proc_stop_callout(void *); 122 static int sigchecktrace(void); 123 static int sigpost(struct lwp *, sig_t, int, int); 124 static int sigput(sigpend_t *, struct proc *, ksiginfo_t *); 125 static int sigunwait(struct proc *, const ksiginfo_t *); 126 static void sigswitch(bool, int, int); 127 128 static void sigacts_poolpage_free(struct pool *, void *); 129 static void *sigacts_poolpage_alloc(struct pool *, int); 130 131 void (*sendsig_sigcontext_vec)(const struct ksiginfo *, const sigset_t *); 132 int (*coredump_vec)(struct lwp *, const char *) = 133 (int (*)(struct lwp *, const char *))enosys; 134 135 /* 136 * DTrace SDT provider definitions 137 */ 138 SDT_PROVIDER_DECLARE(proc); 139 SDT_PROBE_DEFINE3(proc, kernel, , signal__send, 140 "struct lwp *", /* target thread */ 141 "struct proc *", /* target process */ 142 "int"); /* signal */ 143 SDT_PROBE_DEFINE3(proc, kernel, , signal__discard, 144 "struct lwp *", /* target thread */ 145 "struct proc *", /* target process */ 146 "int"); /* signal */ 147 SDT_PROBE_DEFINE3(proc, kernel, , signal__handle, 148 "int", /* signal */ 149 "ksiginfo_t *", /* signal info */ 150 "void (*)(void)"); /* handler address */ 151 152 153 static struct pool_allocator sigactspool_allocator = { 154 .pa_alloc = sigacts_poolpage_alloc, 155 .pa_free = sigacts_poolpage_free 156 }; 157 158 #ifdef DEBUG 159 int kern_logsigexit = 1; 160 #else 161 int kern_logsigexit = 0; 162 #endif 163 164 static const char logcoredump[] = 165 "pid %d (%s), uid %d: exited on signal %d (core dumped)\n"; 166 static const char lognocoredump[] = 167 "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n"; 168 169 static kauth_listener_t signal_listener; 170 171 static int 172 signal_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 173 void *arg0, void *arg1, void *arg2, void *arg3) 174 { 175 struct proc *p; 176 int result, signum; 177 178 result = KAUTH_RESULT_DEFER; 179 p = arg0; 180 signum = (int)(unsigned long)arg1; 181 182 if (action != KAUTH_PROCESS_SIGNAL) 183 return result; 184 185 if (kauth_cred_uidmatch(cred, p->p_cred) || 186 (signum == SIGCONT && (curproc->p_session == p->p_session))) 187 result = KAUTH_RESULT_ALLOW; 188 189 return result; 190 } 191 192 /* 193 * signal_init: 194 * 195 * Initialize global signal-related data structures. 196 */ 197 void 198 signal_init(void) 199 { 200 201 sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2; 202 203 sigacts_cache = pool_cache_init(sizeof(struct sigacts), 0, 0, 0, 204 "sigacts", sizeof(struct sigacts) > PAGE_SIZE ? 205 &sigactspool_allocator : NULL, IPL_NONE, NULL, NULL, NULL); 206 ksiginfo_cache = pool_cache_init(sizeof(ksiginfo_t), 0, 0, 0, 207 "ksiginfo", NULL, IPL_VM, NULL, NULL, NULL); 208 209 exechook_establish(ksiginfo_exechook, NULL); 210 211 callout_init(&proc_stop_ch, CALLOUT_MPSAFE); 212 callout_setfunc(&proc_stop_ch, proc_stop_callout, NULL); 213 214 signal_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS, 215 signal_listener_cb, NULL); 216 } 217 218 /* 219 * sigacts_poolpage_alloc: 220 * 221 * Allocate a page for the sigacts memory pool. 222 */ 223 static void * 224 sigacts_poolpage_alloc(struct pool *pp, int flags) 225 { 226 227 return (void *)uvm_km_alloc(kernel_map, 228 PAGE_SIZE * 2, PAGE_SIZE * 2, 229 ((flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK) 230 | UVM_KMF_WIRED); 231 } 232 233 /* 234 * sigacts_poolpage_free: 235 * 236 * Free a page on behalf of the sigacts memory pool. 237 */ 238 static void 239 sigacts_poolpage_free(struct pool *pp, void *v) 240 { 241 242 uvm_km_free(kernel_map, (vaddr_t)v, PAGE_SIZE * 2, UVM_KMF_WIRED); 243 } 244 245 /* 246 * sigactsinit: 247 * 248 * Create an initial sigacts structure, using the same signal state 249 * as of specified process. If 'share' is set, share the sigacts by 250 * holding a reference, otherwise just copy it from parent. 251 */ 252 struct sigacts * 253 sigactsinit(struct proc *pp, int share) 254 { 255 struct sigacts *ps = pp->p_sigacts, *ps2; 256 257 if (__predict_false(share)) { 258 atomic_inc_uint(&ps->sa_refcnt); 259 return ps; 260 } 261 ps2 = pool_cache_get(sigacts_cache, PR_WAITOK); 262 mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 263 ps2->sa_refcnt = 1; 264 265 mutex_enter(&ps->sa_mutex); 266 memcpy(ps2->sa_sigdesc, ps->sa_sigdesc, sizeof(ps2->sa_sigdesc)); 267 mutex_exit(&ps->sa_mutex); 268 return ps2; 269 } 270 271 /* 272 * sigactsunshare: 273 * 274 * Make this process not share its sigacts, maintaining all signal state. 275 */ 276 void 277 sigactsunshare(struct proc *p) 278 { 279 struct sigacts *ps, *oldps = p->p_sigacts; 280 281 if (__predict_true(oldps->sa_refcnt == 1)) 282 return; 283 284 ps = pool_cache_get(sigacts_cache, PR_WAITOK); 285 mutex_init(&ps->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); 286 memcpy(ps->sa_sigdesc, oldps->sa_sigdesc, sizeof(ps->sa_sigdesc)); 287 ps->sa_refcnt = 1; 288 289 p->p_sigacts = ps; 290 sigactsfree(oldps); 291 } 292 293 /* 294 * sigactsfree; 295 * 296 * Release a sigacts structure. 297 */ 298 void 299 sigactsfree(struct sigacts *ps) 300 { 301 302 if (atomic_dec_uint_nv(&ps->sa_refcnt) == 0) { 303 mutex_destroy(&ps->sa_mutex); 304 pool_cache_put(sigacts_cache, ps); 305 } 306 } 307 308 /* 309 * siginit: 310 * 311 * Initialize signal state for process 0; set to ignore signals that 312 * are ignored by default and disable the signal stack. Locking not 313 * required as the system is still cold. 314 */ 315 void 316 siginit(struct proc *p) 317 { 318 struct lwp *l; 319 struct sigacts *ps; 320 int signo, prop; 321 322 ps = p->p_sigacts; 323 sigemptyset(&contsigmask); 324 sigemptyset(&stopsigmask); 325 sigemptyset(&sigcantmask); 326 for (signo = 1; signo < NSIG; signo++) { 327 prop = sigprop[signo]; 328 if (prop & SA_CONT) 329 sigaddset(&contsigmask, signo); 330 if (prop & SA_STOP) 331 sigaddset(&stopsigmask, signo); 332 if (prop & SA_CANTMASK) 333 sigaddset(&sigcantmask, signo); 334 if (prop & SA_IGNORE && signo != SIGCONT) 335 sigaddset(&p->p_sigctx.ps_sigignore, signo); 336 sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); 337 SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; 338 } 339 sigemptyset(&p->p_sigctx.ps_sigcatch); 340 p->p_sflag &= ~PS_NOCLDSTOP; 341 342 ksiginfo_queue_init(&p->p_sigpend.sp_info); 343 sigemptyset(&p->p_sigpend.sp_set); 344 345 /* 346 * Reset per LWP state. 347 */ 348 l = LIST_FIRST(&p->p_lwps); 349 l->l_sigwaited = NULL; 350 l->l_sigstk = SS_INIT; 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_INIT; 419 ksiginfo_queue_init(&l->l_sigpend.sp_info); 420 sigemptyset(&l->l_sigpend.sp_set); 421 mutex_exit(p->p_lock); 422 423 ksiginfo_queue_drain(&kq); 424 } 425 426 /* 427 * ksiginfo_exechook: 428 * 429 * Free all pending ksiginfo entries from a process on exec. 430 * Additionally, drain any unused ksiginfo structures in the 431 * system back to the pool. 432 * 433 * XXX This should not be a hook, every process has signals. 434 */ 435 static void 436 ksiginfo_exechook(struct proc *p, void *v) 437 { 438 ksiginfoq_t kq; 439 440 ksiginfo_queue_init(&kq); 441 442 mutex_enter(p->p_lock); 443 sigclearall(p, NULL, &kq); 444 mutex_exit(p->p_lock); 445 446 ksiginfo_queue_drain(&kq); 447 } 448 449 /* 450 * ksiginfo_alloc: 451 * 452 * Allocate a new ksiginfo structure from the pool, and optionally copy 453 * an existing one. If the existing ksiginfo_t is from the pool, and 454 * has not been queued somewhere, then just return it. Additionally, 455 * if the existing ksiginfo_t does not contain any information beyond 456 * the signal number, then just return it. 457 */ 458 ksiginfo_t * 459 ksiginfo_alloc(struct proc *p, ksiginfo_t *ok, int flags) 460 { 461 ksiginfo_t *kp; 462 463 if (ok != NULL) { 464 if ((ok->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) == 465 KSI_FROMPOOL) 466 return ok; 467 if (KSI_EMPTY_P(ok)) 468 return ok; 469 } 470 471 kp = pool_cache_get(ksiginfo_cache, flags); 472 if (kp == NULL) { 473 #ifdef DIAGNOSTIC 474 printf("Out of memory allocating ksiginfo for pid %d\n", 475 p->p_pid); 476 #endif 477 return NULL; 478 } 479 480 if (ok != NULL) { 481 memcpy(kp, ok, sizeof(*kp)); 482 kp->ksi_flags &= ~KSI_QUEUED; 483 } else 484 KSI_INIT_EMPTY(kp); 485 486 kp->ksi_flags |= KSI_FROMPOOL; 487 488 return kp; 489 } 490 491 /* 492 * ksiginfo_free: 493 * 494 * If the given ksiginfo_t is from the pool and has not been queued, 495 * then free it. 496 */ 497 void 498 ksiginfo_free(ksiginfo_t *kp) 499 { 500 501 if ((kp->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) != KSI_FROMPOOL) 502 return; 503 pool_cache_put(ksiginfo_cache, kp); 504 } 505 506 /* 507 * ksiginfo_queue_drain: 508 * 509 * Drain a non-empty ksiginfo_t queue. 510 */ 511 void 512 ksiginfo_queue_drain0(ksiginfoq_t *kq) 513 { 514 ksiginfo_t *ksi; 515 516 KASSERT(!TAILQ_EMPTY(kq)); 517 518 while (!TAILQ_EMPTY(kq)) { 519 ksi = TAILQ_FIRST(kq); 520 TAILQ_REMOVE(kq, ksi, ksi_list); 521 pool_cache_put(ksiginfo_cache, ksi); 522 } 523 } 524 525 static int 526 siggetinfo(sigpend_t *sp, ksiginfo_t *out, int signo) 527 { 528 ksiginfo_t *ksi, *nksi; 529 530 if (sp == NULL) 531 goto out; 532 533 /* Find siginfo and copy it out. */ 534 int count = 0; 535 TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, nksi) { 536 if (ksi->ksi_signo != signo) 537 continue; 538 if (count++ > 0) /* Only remove the first, count all of them */ 539 continue; 540 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 541 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 542 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 543 ksi->ksi_flags &= ~KSI_QUEUED; 544 if (out != NULL) { 545 memcpy(out, ksi, sizeof(*out)); 546 out->ksi_flags &= ~(KSI_FROMPOOL | KSI_QUEUED); 547 } 548 ksiginfo_free(ksi); 549 } 550 if (count) 551 return count; 552 553 out: 554 /* If there is no siginfo, then manufacture it. */ 555 if (out != NULL) { 556 KSI_INIT(out); 557 out->ksi_info._signo = signo; 558 out->ksi_info._code = SI_NOINFO; 559 } 560 return 0; 561 } 562 563 /* 564 * sigget: 565 * 566 * Fetch the first pending signal from a set. Optionally, also fetch 567 * or manufacture a ksiginfo element. Returns the number of the first 568 * pending signal, or zero. 569 */ 570 int 571 sigget(sigpend_t *sp, ksiginfo_t *out, int signo, const sigset_t *mask) 572 { 573 sigset_t tset; 574 int count; 575 576 /* If there's no pending set, the signal is from the debugger. */ 577 if (sp == NULL) 578 goto out; 579 580 /* Construct mask from signo, and 'mask'. */ 581 if (signo == 0) { 582 if (mask != NULL) { 583 tset = *mask; 584 __sigandset(&sp->sp_set, &tset); 585 } else 586 tset = sp->sp_set; 587 588 /* If there are no signals pending - return. */ 589 if ((signo = firstsig(&tset)) == 0) 590 goto out; 591 } else { 592 KASSERT(sigismember(&sp->sp_set, signo)); 593 } 594 595 sigdelset(&sp->sp_set, signo); 596 out: 597 count = siggetinfo(sp, out, signo); 598 if (count > 1) 599 sigaddset(&sp->sp_set, signo); 600 return signo; 601 } 602 603 /* 604 * sigput: 605 * 606 * Append a new ksiginfo element to the list of pending ksiginfo's. 607 */ 608 static int 609 sigput(sigpend_t *sp, struct proc *p, ksiginfo_t *ksi) 610 { 611 ksiginfo_t *kp; 612 613 KASSERT(mutex_owned(p->p_lock)); 614 KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); 615 616 sigaddset(&sp->sp_set, ksi->ksi_signo); 617 618 /* 619 * If there is no siginfo, we are done. 620 */ 621 if (KSI_EMPTY_P(ksi)) 622 return 0; 623 624 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 625 626 size_t count = 0; 627 TAILQ_FOREACH(kp, &sp->sp_info, ksi_list) { 628 count++; 629 if (ksi->ksi_signo >= SIGRTMIN && ksi->ksi_signo <= SIGRTMAX) 630 continue; 631 if (kp->ksi_signo == ksi->ksi_signo) { 632 KSI_COPY(ksi, kp); 633 kp->ksi_flags |= KSI_QUEUED; 634 return 0; 635 } 636 } 637 638 if (count >= SIGQUEUE_MAX) { 639 #ifdef DIAGNOSTIC 640 printf("%s(%d): Signal queue is full signal=%d\n", 641 p->p_comm, p->p_pid, ksi->ksi_signo); 642 #endif 643 return EAGAIN; 644 } 645 ksi->ksi_flags |= KSI_QUEUED; 646 TAILQ_INSERT_TAIL(&sp->sp_info, ksi, ksi_list); 647 648 return 0; 649 } 650 651 /* 652 * sigclear: 653 * 654 * Clear all pending signals in the specified set. 655 */ 656 void 657 sigclear(sigpend_t *sp, const sigset_t *mask, ksiginfoq_t *kq) 658 { 659 ksiginfo_t *ksi, *next; 660 661 if (mask == NULL) 662 sigemptyset(&sp->sp_set); 663 else 664 sigminusset(mask, &sp->sp_set); 665 666 TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, next) { 667 if (mask == NULL || sigismember(mask, ksi->ksi_signo)) { 668 TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); 669 KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); 670 KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); 671 TAILQ_INSERT_TAIL(kq, ksi, ksi_list); 672 } 673 } 674 } 675 676 /* 677 * sigclearall: 678 * 679 * Clear all pending signals in the specified set from a process and 680 * its LWPs. 681 */ 682 void 683 sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq) 684 { 685 struct lwp *l; 686 687 KASSERT(mutex_owned(p->p_lock)); 688 689 sigclear(&p->p_sigpend, mask, kq); 690 691 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 692 sigclear(&l->l_sigpend, mask, kq); 693 } 694 } 695 696 /* 697 * sigispending: 698 * 699 * Return the first signal number if there are pending signals for the 700 * current LWP. May be called unlocked provided that LW_PENDSIG is set, 701 * and that the signal has been posted to the appopriate queue before 702 * LW_PENDSIG is set. 703 */ 704 int 705 sigispending(struct lwp *l, int signo) 706 { 707 struct proc *p = l->l_proc; 708 sigset_t tset; 709 710 membar_consumer(); 711 712 tset = l->l_sigpend.sp_set; 713 sigplusset(&p->p_sigpend.sp_set, &tset); 714 sigminusset(&p->p_sigctx.ps_sigignore, &tset); 715 sigminusset(&l->l_sigmask, &tset); 716 717 if (signo == 0) { 718 return firstsig(&tset); 719 } 720 return sigismember(&tset, signo) ? signo : 0; 721 } 722 723 void 724 getucontext(struct lwp *l, ucontext_t *ucp) 725 { 726 struct proc *p = l->l_proc; 727 728 KASSERT(mutex_owned(p->p_lock)); 729 730 ucp->uc_flags = 0; 731 ucp->uc_link = l->l_ctxlink; 732 ucp->uc_sigmask = l->l_sigmask; 733 ucp->uc_flags |= _UC_SIGMASK; 734 735 /* 736 * The (unsupplied) definition of the `current execution stack' 737 * in the System V Interface Definition appears to allow returning 738 * the main context stack. 739 */ 740 if ((l->l_sigstk.ss_flags & SS_ONSTACK) == 0) { 741 ucp->uc_stack.ss_sp = (void *)l->l_proc->p_stackbase; 742 ucp->uc_stack.ss_size = ctob(l->l_proc->p_vmspace->vm_ssize); 743 ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */ 744 } else { 745 /* Simply copy alternate signal execution stack. */ 746 ucp->uc_stack = l->l_sigstk; 747 } 748 ucp->uc_flags |= _UC_STACK; 749 mutex_exit(p->p_lock); 750 cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags); 751 mutex_enter(p->p_lock); 752 } 753 754 int 755 setucontext(struct lwp *l, const ucontext_t *ucp) 756 { 757 struct proc *p = l->l_proc; 758 int error; 759 760 KASSERT(mutex_owned(p->p_lock)); 761 762 if ((ucp->uc_flags & _UC_SIGMASK) != 0) { 763 error = sigprocmask1(l, SIG_SETMASK, &ucp->uc_sigmask, NULL); 764 if (error != 0) 765 return error; 766 } 767 768 mutex_exit(p->p_lock); 769 error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags); 770 mutex_enter(p->p_lock); 771 if (error != 0) 772 return (error); 773 774 l->l_ctxlink = ucp->uc_link; 775 776 /* 777 * If there was stack information, update whether or not we are 778 * still running on an alternate signal stack. 779 */ 780 if ((ucp->uc_flags & _UC_STACK) != 0) { 781 if (ucp->uc_stack.ss_flags & SS_ONSTACK) 782 l->l_sigstk.ss_flags |= SS_ONSTACK; 783 else 784 l->l_sigstk.ss_flags &= ~SS_ONSTACK; 785 } 786 787 return 0; 788 } 789 790 /* 791 * killpg1: common code for kill process group/broadcast kill. 792 */ 793 int 794 killpg1(struct lwp *l, ksiginfo_t *ksi, int pgid, int all) 795 { 796 struct proc *p, *cp; 797 kauth_cred_t pc; 798 struct pgrp *pgrp; 799 int nfound; 800 int signo = ksi->ksi_signo; 801 802 cp = l->l_proc; 803 pc = l->l_cred; 804 nfound = 0; 805 806 mutex_enter(proc_lock); 807 if (all) { 808 /* 809 * Broadcast. 810 */ 811 PROCLIST_FOREACH(p, &allproc) { 812 if (p->p_pid <= 1 || p == cp || 813 (p->p_flag & PK_SYSTEM) != 0) 814 continue; 815 mutex_enter(p->p_lock); 816 if (kauth_authorize_process(pc, 817 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signo), NULL, 818 NULL) == 0) { 819 nfound++; 820 if (signo) 821 kpsignal2(p, ksi); 822 } 823 mutex_exit(p->p_lock); 824 } 825 } else { 826 if (pgid == 0) 827 /* Zero pgid means send to my process group. */ 828 pgrp = cp->p_pgrp; 829 else { 830 pgrp = pgrp_find(pgid); 831 if (pgrp == NULL) 832 goto out; 833 } 834 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 835 if (p->p_pid <= 1 || p->p_flag & PK_SYSTEM) 836 continue; 837 mutex_enter(p->p_lock); 838 if (kauth_authorize_process(pc, KAUTH_PROCESS_SIGNAL, 839 p, KAUTH_ARG(signo), NULL, NULL) == 0) { 840 nfound++; 841 if (signo && P_ZOMBIE(p) == 0) 842 kpsignal2(p, ksi); 843 } 844 mutex_exit(p->p_lock); 845 } 846 } 847 out: 848 mutex_exit(proc_lock); 849 return nfound ? 0 : ESRCH; 850 } 851 852 /* 853 * Send a signal to a process group. If checktty is set, limit to members 854 * which have a controlling terminal. 855 */ 856 void 857 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 858 { 859 ksiginfo_t ksi; 860 861 KASSERT(!cpu_intr_p()); 862 KASSERT(mutex_owned(proc_lock)); 863 864 KSI_INIT_EMPTY(&ksi); 865 ksi.ksi_signo = sig; 866 kpgsignal(pgrp, &ksi, NULL, checkctty); 867 } 868 869 void 870 kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty) 871 { 872 struct proc *p; 873 874 KASSERT(!cpu_intr_p()); 875 KASSERT(mutex_owned(proc_lock)); 876 KASSERT(pgrp != NULL); 877 878 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) 879 if (checkctty == 0 || p->p_lflag & PL_CONTROLT) 880 kpsignal(p, ksi, data); 881 } 882 883 /* 884 * Send a signal caused by a trap to the current LWP. If it will be caught 885 * immediately, deliver it with correct code. Otherwise, post it normally. 886 */ 887 void 888 trapsignal(struct lwp *l, ksiginfo_t *ksi) 889 { 890 struct proc *p; 891 struct sigacts *ps; 892 int signo = ksi->ksi_signo; 893 sigset_t *mask; 894 895 KASSERT(KSI_TRAP_P(ksi)); 896 897 ksi->ksi_lid = l->l_lid; 898 p = l->l_proc; 899 900 KASSERT(!cpu_intr_p()); 901 mutex_enter(proc_lock); 902 mutex_enter(p->p_lock); 903 mask = &l->l_sigmask; 904 ps = p->p_sigacts; 905 906 if ((p->p_slflag & PSL_TRACED) == 0 && 907 sigismember(&p->p_sigctx.ps_sigcatch, signo) && 908 !sigismember(mask, signo)) { 909 mutex_exit(proc_lock); 910 l->l_ru.ru_nsignals++; 911 kpsendsig(l, ksi, mask); 912 mutex_exit(p->p_lock); 913 if (ktrpoint(KTR_PSIG)) { 914 if (p->p_emul->e_ktrpsig) 915 p->p_emul->e_ktrpsig(signo, 916 SIGACTION_PS(ps, signo).sa_handler, 917 mask, ksi); 918 else 919 ktrpsig(signo, 920 SIGACTION_PS(ps, signo).sa_handler, 921 mask, ksi); 922 } 923 } else { 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, debtrap = false; 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 == SIDL && signo == SIGTRAP 1237 && (p->p_slflag & PSL_TRACED)) { 1238 /* allow an initial SIGTRAP for traced processes */ 1239 debtrap = true; 1240 } else if (p->p_stat != SACTIVE && p->p_stat != SSTOP) { 1241 return 0; 1242 } 1243 1244 /* XXX for core dump/debugger */ 1245 p->p_sigctx.ps_lwp = ksi->ksi_lid; 1246 p->p_sigctx.ps_info = ksi->ksi_info; 1247 1248 /* 1249 * Notify any interested parties of the signal. 1250 */ 1251 KNOTE(&p->p_klist, NOTE_SIGNAL | signo); 1252 1253 /* 1254 * Some signals including SIGKILL must act on the entire process. 1255 */ 1256 kp = NULL; 1257 prop = sigprop[signo]; 1258 toall = ((prop & SA_TOALL) != 0); 1259 lid = toall ? 0 : ksi->ksi_lid; 1260 1261 /* 1262 * If proc is traced, always give parent a chance. 1263 */ 1264 if (p->p_slflag & PSL_TRACED) { 1265 action = SIG_DFL; 1266 1267 if (lid == 0) { 1268 /* 1269 * If the process is being traced and the signal 1270 * is being caught, make sure to save any ksiginfo. 1271 */ 1272 if ((kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1273 goto discard; 1274 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1275 goto out; 1276 } 1277 } else { 1278 /* 1279 * If the signal was the result of a trap and is not being 1280 * caught, then reset it to default action so that the 1281 * process dumps core immediately. 1282 */ 1283 if (KSI_TRAP_P(ksi)) { 1284 sa = p->p_sigacts; 1285 mutex_enter(&sa->sa_mutex); 1286 if (!sigismember(&p->p_sigctx.ps_sigcatch, signo)) { 1287 sigdelset(&p->p_sigctx.ps_sigignore, signo); 1288 SIGACTION(p, signo).sa_handler = SIG_DFL; 1289 } 1290 mutex_exit(&sa->sa_mutex); 1291 } 1292 1293 /* 1294 * If the signal is being ignored, then drop it. Note: we 1295 * don't set SIGCONT in ps_sigignore, and if it is set to 1296 * SIG_IGN, action will be SIG_DFL here. 1297 */ 1298 if (sigismember(&p->p_sigctx.ps_sigignore, signo)) 1299 goto discard; 1300 1301 else if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) 1302 action = SIG_CATCH; 1303 else { 1304 action = SIG_DFL; 1305 1306 /* 1307 * If sending a tty stop signal to a member of an 1308 * orphaned process group, discard the signal here if 1309 * the action is default; don't stop the process below 1310 * if sleeping, and don't clear any pending SIGCONT. 1311 */ 1312 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0) 1313 goto discard; 1314 1315 if (prop & SA_KILL && p->p_nice > NZERO) 1316 p->p_nice = NZERO; 1317 } 1318 } 1319 1320 /* 1321 * If stopping or continuing a process, discard any pending 1322 * signals that would do the inverse. 1323 */ 1324 if ((prop & (SA_CONT | SA_STOP)) != 0) { 1325 ksiginfoq_t kq; 1326 1327 ksiginfo_queue_init(&kq); 1328 if ((prop & SA_CONT) != 0) 1329 sigclear(&p->p_sigpend, &stopsigmask, &kq); 1330 if ((prop & SA_STOP) != 0) 1331 sigclear(&p->p_sigpend, &contsigmask, &kq); 1332 ksiginfo_queue_drain(&kq); /* XXXSMP */ 1333 } 1334 1335 /* 1336 * If the signal doesn't have SA_CANTMASK (no override for SIGKILL, 1337 * please!), check if any LWPs are waiting on it. If yes, pass on 1338 * the signal info. The signal won't be processed further here. 1339 */ 1340 if ((prop & SA_CANTMASK) == 0 && !LIST_EMPTY(&p->p_sigwaiters) && 1341 p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0 && 1342 sigunwait(p, ksi)) 1343 goto discard; 1344 1345 /* 1346 * XXXSMP Should be allocated by the caller, we're holding locks 1347 * here. 1348 */ 1349 if (kp == NULL && (kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) 1350 goto discard; 1351 1352 /* 1353 * LWP private signals are easy - just find the LWP and post 1354 * the signal to it. 1355 */ 1356 if (lid != 0) { 1357 if (__predict_false(debtrap)) { 1358 l = LIST_FIRST(&p->p_lwps); 1359 if (l->l_lid != lid) 1360 l = NULL; 1361 } else { 1362 l = lwp_find(p, lid); 1363 } 1364 if (l != NULL) { 1365 if ((error = sigput(&l->l_sigpend, p, kp)) != 0) 1366 goto out; 1367 membar_producer(); 1368 (void)sigpost(l, action, prop, kp->ksi_signo); 1369 } 1370 goto out; 1371 } 1372 1373 /* 1374 * Some signals go to all LWPs, even if posted with _lwp_kill() 1375 * or for an SA process. 1376 */ 1377 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1378 if ((p->p_slflag & PSL_TRACED) != 0) 1379 goto deliver; 1380 1381 /* 1382 * If SIGCONT is default (or ignored) and process is 1383 * asleep, we are finished; the process should not 1384 * be awakened. 1385 */ 1386 if ((prop & SA_CONT) != 0 && action == SIG_DFL) 1387 goto out; 1388 } else { 1389 /* 1390 * Process is stopped or stopping. 1391 * - If traced, then no action is needed, unless killing. 1392 * - Run the process only if sending SIGCONT or SIGKILL. 1393 */ 1394 if ((p->p_slflag & PSL_TRACED) != 0 && signo != SIGKILL) { 1395 goto out; 1396 } 1397 if ((prop & SA_CONT) != 0 || signo == SIGKILL) { 1398 /* 1399 * Re-adjust p_nstopchild if the process was 1400 * stopped but not yet collected by its parent. 1401 */ 1402 if (p->p_stat == SSTOP && !p->p_waited) 1403 p->p_pptr->p_nstopchild--; 1404 p->p_stat = SACTIVE; 1405 p->p_sflag &= ~PS_STOPPING; 1406 if (p->p_slflag & PSL_TRACED) { 1407 KASSERT(signo == SIGKILL); 1408 goto deliver; 1409 } 1410 /* 1411 * Do not make signal pending if SIGCONT is default. 1412 * 1413 * If the process catches SIGCONT, let it handle the 1414 * signal itself (if waiting on event - process runs, 1415 * otherwise continues sleeping). 1416 */ 1417 if ((prop & SA_CONT) != 0) { 1418 p->p_xsig = SIGCONT; 1419 p->p_sflag |= PS_CONTINUED; 1420 child_psignal(p, 0); 1421 if (action == SIG_DFL) { 1422 KASSERT(signo != SIGKILL); 1423 goto deliver; 1424 } 1425 } 1426 } else if ((prop & SA_STOP) != 0) { 1427 /* 1428 * Already stopped, don't need to stop again. 1429 * (If we did the shell could get confused.) 1430 */ 1431 goto out; 1432 } 1433 } 1434 /* 1435 * Make signal pending. 1436 */ 1437 KASSERT((p->p_slflag & PSL_TRACED) == 0); 1438 if ((error = sigput(&p->p_sigpend, p, kp)) != 0) 1439 goto out; 1440 deliver: 1441 /* 1442 * Before we set LW_PENDSIG on any LWP, ensure that the signal is 1443 * visible on the per process list (for sigispending()). This 1444 * is unlikely to be needed in practice, but... 1445 */ 1446 membar_producer(); 1447 1448 /* 1449 * Try to find an LWP that can take the signal. 1450 */ 1451 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1452 if (sigpost(l, action, prop, kp->ksi_signo) && !toall) 1453 break; 1454 } 1455 signo = -1; 1456 out: 1457 /* 1458 * If the ksiginfo wasn't used, then bin it. XXXSMP freeing memory 1459 * with locks held. The caller should take care of this. 1460 */ 1461 ksiginfo_free(kp); 1462 if (signo == -1) 1463 return error; 1464 discard: 1465 SDT_PROBE(proc, kernel, , signal__discard, l, p, signo, 0, 0); 1466 return error; 1467 } 1468 1469 void 1470 kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask) 1471 { 1472 struct proc *p = l->l_proc; 1473 1474 KASSERT(mutex_owned(p->p_lock)); 1475 (*p->p_emul->e_sendsig)(ksi, mask); 1476 } 1477 1478 /* 1479 * Stop any LWPs sleeping interruptably. 1480 */ 1481 static void 1482 proc_stop_lwps(struct proc *p) 1483 { 1484 struct lwp *l; 1485 1486 KASSERT(mutex_owned(p->p_lock)); 1487 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1488 1489 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 1490 lwp_lock(l); 1491 if (l->l_stat == LSSLEEP && (l->l_flag & LW_SINTR) != 0) { 1492 l->l_stat = LSSTOP; 1493 p->p_nrlwps--; 1494 } 1495 lwp_unlock(l); 1496 } 1497 } 1498 1499 /* 1500 * Finish stopping of a process. Mark it stopped and notify the parent. 1501 * 1502 * Drop p_lock briefly if PS_NOTIFYSTOP is set and ppsig is true. 1503 */ 1504 static void 1505 proc_stop_done(struct proc *p, bool ppsig, int ppmask) 1506 { 1507 1508 KASSERT(mutex_owned(proc_lock)); 1509 KASSERT(mutex_owned(p->p_lock)); 1510 KASSERT((p->p_sflag & PS_STOPPING) != 0); 1511 KASSERT(p->p_nrlwps == 0 || (p->p_nrlwps == 1 && p == curproc)); 1512 1513 p->p_sflag &= ~PS_STOPPING; 1514 p->p_stat = SSTOP; 1515 p->p_waited = 0; 1516 p->p_pptr->p_nstopchild++; 1517 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 1518 if (ppsig) { 1519 /* child_psignal drops p_lock briefly. */ 1520 child_psignal(p, ppmask); 1521 } 1522 cv_broadcast(&p->p_pptr->p_waitcv); 1523 } 1524 } 1525 1526 /* 1527 * Stop the current process and switch away when being stopped or traced. 1528 */ 1529 static void 1530 sigswitch(bool ppsig, int ppmask, int signo) 1531 { 1532 struct lwp *l = curlwp; 1533 struct proc *p = l->l_proc; 1534 int biglocks; 1535 1536 KASSERT(mutex_owned(p->p_lock)); 1537 KASSERT(l->l_stat == LSONPROC); 1538 KASSERT(p->p_nrlwps > 0); 1539 1540 /* 1541 * On entry we know that the process needs to stop. If it's 1542 * the result of a 'sideways' stop signal that has been sourced 1543 * through issignal(), then stop other LWPs in the process too. 1544 */ 1545 if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { 1546 KASSERT(signo != 0); 1547 proc_stop(p, signo); 1548 KASSERT(p->p_nrlwps > 0); 1549 } 1550 1551 /* 1552 * If we are the last live LWP, and the stop was a result of 1553 * a new signal, then signal the parent. 1554 */ 1555 if ((p->p_sflag & PS_STOPPING) != 0) { 1556 if (!mutex_tryenter(proc_lock)) { 1557 mutex_exit(p->p_lock); 1558 mutex_enter(proc_lock); 1559 mutex_enter(p->p_lock); 1560 } 1561 1562 if (p->p_nrlwps == 1 && (p->p_sflag & PS_STOPPING) != 0) { 1563 /* 1564 * Note that proc_stop_done() can drop 1565 * p->p_lock briefly. 1566 */ 1567 proc_stop_done(p, ppsig, ppmask); 1568 } 1569 1570 mutex_exit(proc_lock); 1571 } 1572 1573 /* 1574 * Unlock and switch away. 1575 */ 1576 KERNEL_UNLOCK_ALL(l, &biglocks); 1577 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1578 p->p_nrlwps--; 1579 lwp_lock(l); 1580 KASSERT(l->l_stat == LSONPROC || l->l_stat == LSSLEEP); 1581 l->l_stat = LSSTOP; 1582 lwp_unlock(l); 1583 } 1584 1585 mutex_exit(p->p_lock); 1586 lwp_lock(l); 1587 mi_switch(l); 1588 KERNEL_LOCK(biglocks, l); 1589 mutex_enter(p->p_lock); 1590 } 1591 1592 /* 1593 * Check for a signal from the debugger. 1594 */ 1595 static int 1596 sigchecktrace(void) 1597 { 1598 struct lwp *l = curlwp; 1599 struct proc *p = l->l_proc; 1600 int signo; 1601 1602 KASSERT(mutex_owned(p->p_lock)); 1603 1604 /* If there's a pending SIGKILL, process it immediately. */ 1605 if (sigismember(&p->p_sigpend.sp_set, SIGKILL)) 1606 return 0; 1607 1608 /* 1609 * If we are no longer being traced, or the parent didn't 1610 * give us a signal, or we're stopping, look for more signals. 1611 */ 1612 if ((p->p_slflag & PSL_TRACED) == 0 || p->p_xsig == 0 || 1613 (p->p_sflag & PS_STOPPING) != 0) 1614 return 0; 1615 1616 /* 1617 * If the new signal is being masked, look for other signals. 1618 * `p->p_sigctx.ps_siglist |= mask' is done in setrunnable(). 1619 */ 1620 signo = p->p_xsig; 1621 p->p_xsig = 0; 1622 if (sigismember(&l->l_sigmask, signo)) { 1623 signo = 0; 1624 } 1625 return signo; 1626 } 1627 1628 /* 1629 * If the current process has received a signal (should be caught or cause 1630 * termination, should interrupt current syscall), return the signal number. 1631 * 1632 * Stop signals with default action are processed immediately, then cleared; 1633 * they aren't returned. This is checked after each entry to the system for 1634 * a syscall or trap. 1635 * 1636 * We will also return -1 if the process is exiting and the current LWP must 1637 * follow suit. 1638 */ 1639 int 1640 issignal(struct lwp *l) 1641 { 1642 struct proc *p; 1643 int signo, prop; 1644 sigpend_t *sp; 1645 sigset_t ss; 1646 1647 p = l->l_proc; 1648 sp = NULL; 1649 signo = 0; 1650 1651 KASSERT(p == curproc); 1652 KASSERT(mutex_owned(p->p_lock)); 1653 1654 for (;;) { 1655 /* Discard any signals that we have decided not to take. */ 1656 if (signo != 0) { 1657 (void)sigget(sp, NULL, signo, NULL); 1658 } 1659 1660 /* 1661 * If the process is stopped/stopping, then stop ourselves 1662 * now that we're on the kernel/userspace boundary. When 1663 * we awaken, check for a signal from the debugger. 1664 */ 1665 if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { 1666 sigswitch(true, PS_NOCLDSTOP, 0); 1667 signo = sigchecktrace(); 1668 } else 1669 signo = 0; 1670 1671 /* Signals from the debugger are "out of band". */ 1672 sp = NULL; 1673 1674 /* 1675 * If the debugger didn't provide a signal, find a pending 1676 * signal from our set. Check per-LWP signals first, and 1677 * then per-process. 1678 */ 1679 if (signo == 0) { 1680 sp = &l->l_sigpend; 1681 ss = sp->sp_set; 1682 if ((p->p_lflag & PL_PPWAIT) != 0) 1683 sigminusset(&stopsigmask, &ss); 1684 sigminusset(&l->l_sigmask, &ss); 1685 1686 if ((signo = firstsig(&ss)) == 0) { 1687 sp = &p->p_sigpend; 1688 ss = sp->sp_set; 1689 if ((p->p_lflag & PL_PPWAIT) != 0) 1690 sigminusset(&stopsigmask, &ss); 1691 sigminusset(&l->l_sigmask, &ss); 1692 1693 if ((signo = firstsig(&ss)) == 0) { 1694 /* 1695 * No signal pending - clear the 1696 * indicator and bail out. 1697 */ 1698 lwp_lock(l); 1699 l->l_flag &= ~LW_PENDSIG; 1700 lwp_unlock(l); 1701 sp = NULL; 1702 break; 1703 } 1704 } 1705 } 1706 1707 /* 1708 * We should see pending but ignored signals only if 1709 * we are being traced. 1710 */ 1711 if (sigismember(&p->p_sigctx.ps_sigignore, signo) && 1712 (p->p_slflag & PSL_TRACED) == 0) { 1713 /* Discard the signal. */ 1714 continue; 1715 } 1716 1717 /* 1718 * If traced, always stop, and stay stopped until released 1719 * by the debugger. If the our parent process is waiting 1720 * for us, don't hang as we could deadlock. 1721 */ 1722 if ((p->p_slflag & PSL_TRACED) != 0 && 1723 (p->p_lflag & PL_PPWAIT) == 0 && signo != SIGKILL) { 1724 /* 1725 * Take the signal, but don't remove it from the 1726 * siginfo queue, because the debugger can send 1727 * it later. 1728 */ 1729 if (sp) 1730 sigdelset(&sp->sp_set, signo); 1731 p->p_xsig = signo; 1732 1733 /* Emulation-specific handling of signal trace */ 1734 if (p->p_emul->e_tracesig == NULL || 1735 (*p->p_emul->e_tracesig)(p, signo) == 0) 1736 sigswitch(1, 0, signo); 1737 1738 /* Check for a signal from the debugger. */ 1739 if ((signo = sigchecktrace()) == 0) 1740 continue; 1741 1742 /* Signals from the debugger are "out of band". */ 1743 sp = NULL; 1744 } 1745 1746 prop = sigprop[signo]; 1747 1748 /* 1749 * Decide whether the signal should be returned. 1750 */ 1751 switch ((long)SIGACTION(p, signo).sa_handler) { 1752 case (long)SIG_DFL: 1753 /* 1754 * Don't take default actions on system processes. 1755 */ 1756 if (p->p_pid <= 1) { 1757 #ifdef DIAGNOSTIC 1758 /* 1759 * Are you sure you want to ignore SIGSEGV 1760 * in init? XXX 1761 */ 1762 printf_nolog("Process (pid %d) got sig %d\n", 1763 p->p_pid, signo); 1764 #endif 1765 continue; 1766 } 1767 1768 /* 1769 * If there is a pending stop signal to process with 1770 * default action, stop here, then clear the signal. 1771 * However, if process is member of an orphaned 1772 * process group, ignore tty stop signals. 1773 */ 1774 if (prop & SA_STOP) { 1775 /* 1776 * XXX Don't hold proc_lock for p_lflag, 1777 * but it's not a big deal. 1778 */ 1779 if (p->p_slflag & PSL_TRACED || 1780 ((p->p_lflag & PL_ORPHANPG) != 0 && 1781 prop & SA_TTYSTOP)) { 1782 /* Ignore the signal. */ 1783 continue; 1784 } 1785 /* Take the signal. */ 1786 (void)sigget(sp, NULL, signo, NULL); 1787 p->p_xsig = signo; 1788 p->p_sflag &= ~PS_CONTINUED; 1789 signo = 0; 1790 sigswitch(true, PS_NOCLDSTOP, p->p_xsig); 1791 } else if (prop & SA_IGNORE) { 1792 /* 1793 * Except for SIGCONT, shouldn't get here. 1794 * Default action is to ignore; drop it. 1795 */ 1796 continue; 1797 } 1798 break; 1799 1800 case (long)SIG_IGN: 1801 #ifdef DEBUG_ISSIGNAL 1802 /* 1803 * Masking above should prevent us ever trying 1804 * to take action on an ignored signal other 1805 * than SIGCONT, unless process is traced. 1806 */ 1807 if ((prop & SA_CONT) == 0 && 1808 (p->p_slflag & PSL_TRACED) == 0) 1809 printf_nolog("issignal\n"); 1810 #endif 1811 continue; 1812 1813 default: 1814 /* 1815 * This signal has an action, let postsig() process 1816 * it. 1817 */ 1818 break; 1819 } 1820 1821 break; 1822 } 1823 1824 l->l_sigpendset = sp; 1825 return signo; 1826 } 1827 1828 /* 1829 * Take the action for the specified signal 1830 * from the current set of pending signals. 1831 */ 1832 void 1833 postsig(int signo) 1834 { 1835 struct lwp *l; 1836 struct proc *p; 1837 struct sigacts *ps; 1838 sig_t action; 1839 sigset_t *returnmask; 1840 ksiginfo_t ksi; 1841 1842 l = curlwp; 1843 p = l->l_proc; 1844 ps = p->p_sigacts; 1845 1846 KASSERT(mutex_owned(p->p_lock)); 1847 KASSERT(signo > 0); 1848 1849 /* 1850 * Set the new mask value and also defer further occurrences of this 1851 * signal. 1852 * 1853 * Special case: user has done a sigsuspend. Here the current mask is 1854 * not of interest, but rather the mask from before the sigsuspend is 1855 * what we want restored after the signal processing is completed. 1856 */ 1857 if (l->l_sigrestore) { 1858 returnmask = &l->l_sigoldmask; 1859 l->l_sigrestore = 0; 1860 } else 1861 returnmask = &l->l_sigmask; 1862 1863 /* 1864 * Commit to taking the signal before releasing the mutex. 1865 */ 1866 action = SIGACTION_PS(ps, signo).sa_handler; 1867 l->l_ru.ru_nsignals++; 1868 if (l->l_sigpendset == NULL) { 1869 /* From the debugger */ 1870 if (p->p_sigctx.ps_faked && 1871 signo == p->p_sigctx.ps_info._signo) { 1872 KSI_INIT(&ksi); 1873 ksi.ksi_info = p->p_sigctx.ps_info; 1874 ksi.ksi_lid = p->p_sigctx.ps_lwp; 1875 p->p_sigctx.ps_faked = false; 1876 } else { 1877 if (!siggetinfo(&l->l_sigpend, &ksi, signo)) 1878 (void)siggetinfo(&p->p_sigpend, &ksi, signo); 1879 } 1880 } else 1881 sigget(l->l_sigpendset, &ksi, signo, NULL); 1882 1883 if (ktrpoint(KTR_PSIG)) { 1884 mutex_exit(p->p_lock); 1885 if (p->p_emul->e_ktrpsig) 1886 p->p_emul->e_ktrpsig(signo, action, 1887 returnmask, &ksi); 1888 else 1889 ktrpsig(signo, action, returnmask, &ksi); 1890 mutex_enter(p->p_lock); 1891 } 1892 1893 SDT_PROBE(proc, kernel, , signal__handle, signo, &ksi, action, 0, 0); 1894 1895 if (action == SIG_DFL) { 1896 /* 1897 * Default action, where the default is to kill 1898 * the process. (Other cases were ignored above.) 1899 */ 1900 sigexit(l, signo); 1901 return; 1902 } 1903 1904 /* 1905 * If we get here, the signal must be caught. 1906 */ 1907 #ifdef DIAGNOSTIC 1908 if (action == SIG_IGN || sigismember(&l->l_sigmask, signo)) 1909 panic("postsig action"); 1910 #endif 1911 1912 kpsendsig(l, &ksi, returnmask); 1913 } 1914 1915 /* 1916 * sendsig: 1917 * 1918 * Default signal delivery method for NetBSD. 1919 */ 1920 void 1921 sendsig(const struct ksiginfo *ksi, const sigset_t *mask) 1922 { 1923 struct sigacts *sa; 1924 int sig; 1925 1926 sig = ksi->ksi_signo; 1927 sa = curproc->p_sigacts; 1928 1929 switch (sa->sa_sigdesc[sig].sd_vers) { 1930 case 0: 1931 case 1: 1932 /* Compat for 1.6 and earlier. */ 1933 if (sendsig_sigcontext_vec == NULL) { 1934 break; 1935 } 1936 (*sendsig_sigcontext_vec)(ksi, mask); 1937 return; 1938 case 2: 1939 case 3: 1940 sendsig_siginfo(ksi, mask); 1941 return; 1942 default: 1943 break; 1944 } 1945 1946 printf("sendsig: bad version %d\n", sa->sa_sigdesc[sig].sd_vers); 1947 sigexit(curlwp, SIGILL); 1948 } 1949 1950 /* 1951 * sendsig_reset: 1952 * 1953 * Reset the signal action. Called from emulation specific sendsig() 1954 * before unlocking to deliver the signal. 1955 */ 1956 void 1957 sendsig_reset(struct lwp *l, int signo) 1958 { 1959 struct proc *p = l->l_proc; 1960 struct sigacts *ps = p->p_sigacts; 1961 1962 KASSERT(mutex_owned(p->p_lock)); 1963 1964 p->p_sigctx.ps_lwp = 0; 1965 memset(&p->p_sigctx.ps_info, 0, sizeof(p->p_sigctx.ps_info)); 1966 1967 mutex_enter(&ps->sa_mutex); 1968 sigplusset(&SIGACTION_PS(ps, signo).sa_mask, &l->l_sigmask); 1969 if (SIGACTION_PS(ps, signo).sa_flags & SA_RESETHAND) { 1970 sigdelset(&p->p_sigctx.ps_sigcatch, signo); 1971 if (signo != SIGCONT && sigprop[signo] & SA_IGNORE) 1972 sigaddset(&p->p_sigctx.ps_sigignore, signo); 1973 SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; 1974 } 1975 mutex_exit(&ps->sa_mutex); 1976 } 1977 1978 /* 1979 * Kill the current process for stated reason. 1980 */ 1981 void 1982 killproc(struct proc *p, const char *why) 1983 { 1984 1985 KASSERT(mutex_owned(proc_lock)); 1986 1987 log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why); 1988 uprintf_locked("sorry, pid %d was killed: %s\n", p->p_pid, why); 1989 psignal(p, SIGKILL); 1990 } 1991 1992 /* 1993 * Force the current process to exit with the specified signal, dumping core 1994 * if appropriate. We bypass the normal tests for masked and caught 1995 * signals, allowing unrecoverable failures to terminate the process without 1996 * changing signal state. Mark the accounting record with the signal 1997 * termination. If dumping core, save the signal number for the debugger. 1998 * Calls exit and does not return. 1999 */ 2000 void 2001 sigexit(struct lwp *l, int signo) 2002 { 2003 int exitsig, error, docore; 2004 struct proc *p; 2005 struct lwp *t; 2006 2007 p = l->l_proc; 2008 2009 KASSERT(mutex_owned(p->p_lock)); 2010 KERNEL_UNLOCK_ALL(l, NULL); 2011 2012 /* 2013 * Don't permit coredump() multiple times in the same process. 2014 * Call back into sigexit, where we will be suspended until 2015 * the deed is done. Note that this is a recursive call, but 2016 * LW_WCORE will prevent us from coming back this way. 2017 */ 2018 if ((p->p_sflag & PS_WCORE) != 0) { 2019 lwp_lock(l); 2020 l->l_flag |= (LW_WCORE | LW_WEXIT | LW_WSUSPEND); 2021 lwp_unlock(l); 2022 mutex_exit(p->p_lock); 2023 lwp_userret(l); 2024 panic("sigexit 1"); 2025 /* NOTREACHED */ 2026 } 2027 2028 /* If process is already on the way out, then bail now. */ 2029 if ((p->p_sflag & PS_WEXIT) != 0) { 2030 mutex_exit(p->p_lock); 2031 lwp_exit(l); 2032 panic("sigexit 2"); 2033 /* NOTREACHED */ 2034 } 2035 2036 /* 2037 * Prepare all other LWPs for exit. If dumping core, suspend them 2038 * so that their registers are available long enough to be dumped. 2039 */ 2040 if ((docore = (sigprop[signo] & SA_CORE)) != 0) { 2041 p->p_sflag |= PS_WCORE; 2042 for (;;) { 2043 LIST_FOREACH(t, &p->p_lwps, l_sibling) { 2044 lwp_lock(t); 2045 if (t == l) { 2046 t->l_flag &= ~LW_WSUSPEND; 2047 lwp_unlock(t); 2048 continue; 2049 } 2050 t->l_flag |= (LW_WCORE | LW_WEXIT); 2051 lwp_suspend(l, t); 2052 } 2053 2054 if (p->p_nrlwps == 1) 2055 break; 2056 2057 /* 2058 * Kick any LWPs sitting in lwp_wait1(), and wait 2059 * for everyone else to stop before proceeding. 2060 */ 2061 p->p_nlwpwait++; 2062 cv_broadcast(&p->p_lwpcv); 2063 cv_wait(&p->p_lwpcv, p->p_lock); 2064 p->p_nlwpwait--; 2065 } 2066 } 2067 2068 exitsig = signo; 2069 p->p_acflag |= AXSIG; 2070 memset(&p->p_sigctx.ps_info, 0, sizeof(p->p_sigctx.ps_info)); 2071 p->p_sigctx.ps_info._signo = signo; 2072 p->p_sigctx.ps_info._code = SI_NOINFO; 2073 2074 if (docore) { 2075 mutex_exit(p->p_lock); 2076 error = (*coredump_vec)(l, NULL); 2077 2078 if (kern_logsigexit) { 2079 int uid = l->l_cred ? 2080 (int)kauth_cred_geteuid(l->l_cred) : -1; 2081 2082 if (error) 2083 log(LOG_INFO, lognocoredump, p->p_pid, 2084 p->p_comm, uid, signo, error); 2085 else 2086 log(LOG_INFO, logcoredump, p->p_pid, 2087 p->p_comm, uid, signo); 2088 } 2089 2090 #ifdef PAX_SEGVGUARD 2091 pax_segvguard(l, p->p_textvp, p->p_comm, true); 2092 #endif /* PAX_SEGVGUARD */ 2093 /* Acquire the sched state mutex. exit1() will release it. */ 2094 mutex_enter(p->p_lock); 2095 if (error == 0) 2096 p->p_sflag |= PS_COREDUMP; 2097 } 2098 2099 /* No longer dumping core. */ 2100 p->p_sflag &= ~PS_WCORE; 2101 2102 exit1(l, 0, exitsig); 2103 /* NOTREACHED */ 2104 } 2105 2106 /* 2107 * Put process 'p' into the stopped state and optionally, notify the parent. 2108 */ 2109 void 2110 proc_stop(struct proc *p, int signo) 2111 { 2112 struct lwp *l; 2113 2114 KASSERT(mutex_owned(p->p_lock)); 2115 2116 /* 2117 * First off, set the stopping indicator and bring all sleeping 2118 * LWPs to a halt so they are included in p->p_nrlwps. We musn't 2119 * unlock between here and the p->p_nrlwps check below. 2120 */ 2121 p->p_sflag |= PS_STOPPING | PS_NOTIFYSTOP; 2122 membar_producer(); 2123 2124 proc_stop_lwps(p); 2125 2126 /* 2127 * If there are no LWPs available to take the signal, then we 2128 * signal the parent process immediately. Otherwise, the last 2129 * LWP to stop will take care of it. 2130 */ 2131 2132 if (p->p_nrlwps == 0) { 2133 proc_stop_done(p, true, PS_NOCLDSTOP); 2134 } else { 2135 /* 2136 * Have the remaining LWPs come to a halt, and trigger 2137 * proc_stop_callout() to ensure that they do. 2138 */ 2139 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2140 sigpost(l, SIG_DFL, SA_STOP, signo); 2141 } 2142 callout_schedule(&proc_stop_ch, 1); 2143 } 2144 } 2145 2146 /* 2147 * When stopping a process, we do not immediatly set sleeping LWPs stopped, 2148 * but wait for them to come to a halt at the kernel-user boundary. This is 2149 * to allow LWPs to release any locks that they may hold before stopping. 2150 * 2151 * Non-interruptable sleeps can be long, and there is the potential for an 2152 * LWP to begin sleeping interruptably soon after the process has been set 2153 * stopping (PS_STOPPING). These LWPs will not notice that the process is 2154 * stopping, and so complete halt of the process and the return of status 2155 * information to the parent could be delayed indefinitely. 2156 * 2157 * To handle this race, proc_stop_callout() runs once per tick while there 2158 * are stopping processes in the system. It sets LWPs that are sleeping 2159 * interruptably into the LSSTOP state. 2160 * 2161 * Note that we are not concerned about keeping all LWPs stopped while the 2162 * process is stopped: stopped LWPs can awaken briefly to handle signals. 2163 * What we do need to ensure is that all LWPs in a stopping process have 2164 * stopped at least once, so that notification can be sent to the parent 2165 * process. 2166 */ 2167 static void 2168 proc_stop_callout(void *cookie) 2169 { 2170 bool more, restart; 2171 struct proc *p; 2172 2173 (void)cookie; 2174 2175 do { 2176 restart = false; 2177 more = false; 2178 2179 mutex_enter(proc_lock); 2180 PROCLIST_FOREACH(p, &allproc) { 2181 mutex_enter(p->p_lock); 2182 2183 if ((p->p_sflag & PS_STOPPING) == 0) { 2184 mutex_exit(p->p_lock); 2185 continue; 2186 } 2187 2188 /* Stop any LWPs sleeping interruptably. */ 2189 proc_stop_lwps(p); 2190 if (p->p_nrlwps == 0) { 2191 /* 2192 * We brought the process to a halt. 2193 * Mark it as stopped and notify the 2194 * parent. 2195 */ 2196 if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { 2197 /* 2198 * Note that proc_stop_done() will 2199 * drop p->p_lock briefly. 2200 * Arrange to restart and check 2201 * all processes again. 2202 */ 2203 restart = true; 2204 } 2205 proc_stop_done(p, true, PS_NOCLDSTOP); 2206 } else 2207 more = true; 2208 2209 mutex_exit(p->p_lock); 2210 if (restart) 2211 break; 2212 } 2213 mutex_exit(proc_lock); 2214 } while (restart); 2215 2216 /* 2217 * If we noted processes that are stopping but still have 2218 * running LWPs, then arrange to check again in 1 tick. 2219 */ 2220 if (more) 2221 callout_schedule(&proc_stop_ch, 1); 2222 } 2223 2224 /* 2225 * Given a process in state SSTOP, set the state back to SACTIVE and 2226 * move LSSTOP'd LWPs to LSSLEEP or make them runnable. 2227 */ 2228 void 2229 proc_unstop(struct proc *p) 2230 { 2231 struct lwp *l; 2232 int sig; 2233 2234 KASSERT(mutex_owned(proc_lock)); 2235 KASSERT(mutex_owned(p->p_lock)); 2236 2237 p->p_stat = SACTIVE; 2238 p->p_sflag &= ~PS_STOPPING; 2239 sig = p->p_xsig; 2240 2241 if (!p->p_waited) 2242 p->p_pptr->p_nstopchild--; 2243 2244 LIST_FOREACH(l, &p->p_lwps, l_sibling) { 2245 lwp_lock(l); 2246 if (l->l_stat != LSSTOP) { 2247 lwp_unlock(l); 2248 continue; 2249 } 2250 if (l->l_wchan == NULL) { 2251 setrunnable(l); 2252 continue; 2253 } 2254 if (sig && (l->l_flag & LW_SINTR) != 0) { 2255 setrunnable(l); 2256 sig = 0; 2257 } else { 2258 l->l_stat = LSSLEEP; 2259 p->p_nrlwps++; 2260 lwp_unlock(l); 2261 } 2262 } 2263 } 2264 2265 void 2266 proc_stoptrace(int trapno) 2267 { 2268 struct lwp *l = curlwp; 2269 struct proc *p = l->l_proc, *pp; 2270 2271 mutex_enter(p->p_lock); 2272 pp = p->p_pptr; 2273 if (pp->p_pid == 1) { 2274 CLR(p->p_slflag, PSL_SYSCALL); /* XXXSMP */ 2275 mutex_exit(p->p_lock); 2276 return; 2277 } 2278 2279 p->p_xsig = SIGTRAP; 2280 p->p_sigctx.ps_info._signo = p->p_xsig; 2281 p->p_sigctx.ps_info._code = trapno; 2282 sigswitch(true, 0, p->p_xsig); 2283 mutex_exit(p->p_lock); 2284 } 2285 2286 static int 2287 filt_sigattach(struct knote *kn) 2288 { 2289 struct proc *p = curproc; 2290 2291 kn->kn_obj = p; 2292 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2293 2294 mutex_enter(p->p_lock); 2295 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2296 mutex_exit(p->p_lock); 2297 2298 return 0; 2299 } 2300 2301 static void 2302 filt_sigdetach(struct knote *kn) 2303 { 2304 struct proc *p = kn->kn_obj; 2305 2306 mutex_enter(p->p_lock); 2307 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2308 mutex_exit(p->p_lock); 2309 } 2310 2311 /* 2312 * Signal knotes are shared with proc knotes, so we apply a mask to 2313 * the hint in order to differentiate them from process hints. This 2314 * could be avoided by using a signal-specific knote list, but probably 2315 * isn't worth the trouble. 2316 */ 2317 static int 2318 filt_signal(struct knote *kn, long hint) 2319 { 2320 2321 if (hint & NOTE_SIGNAL) { 2322 hint &= ~NOTE_SIGNAL; 2323 2324 if (kn->kn_id == hint) 2325 kn->kn_data++; 2326 } 2327 return (kn->kn_data != 0); 2328 } 2329 2330 const struct filterops sig_filtops = { 2331 .f_isfd = 0, 2332 .f_attach = filt_sigattach, 2333 .f_detach = filt_sigdetach, 2334 .f_event = filt_signal, 2335 }; 2336
Indexes created Wed Sep 24 15:09:51 GMT 2025