1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/ctype.h> 46 #include <sys/systm.h> 47 #include <sys/signalvar.h> 48 #include <sys/vnode.h> 49 #include <sys/acct.h> 50 #include <sys/capsicum.h> 51 #include <sys/compressor.h> 52 #include <sys/condvar.h> 53 #include <sys/devctl.h> 54 #include <sys/event.h> 55 #include <sys/fcntl.h> 56 #include <sys/imgact.h> 57 #include <sys/kernel.h> 58 #include <sys/ktr.h> 59 #include <sys/ktrace.h> 60 #include <sys/limits.h> 61 #include <sys/lock.h> 62 #include <sys/malloc.h> 63 #include <sys/mutex.h> 64 #include <sys/refcount.h> 65 #include <sys/namei.h> 66 #include <sys/proc.h> 67 #include <sys/procdesc.h> 68 #include <sys/ptrace.h> 69 #include <sys/posix4.h> 70 #include <sys/racct.h> 71 #include <sys/resourcevar.h> 72 #include <sys/sdt.h> 73 #include <sys/sbuf.h> 74 #include <sys/sleepqueue.h> 75 #include <sys/smp.h> 76 #include <sys/stat.h> 77 #include <sys/sx.h> 78 #include <sys/syscallsubr.h> 79 #include <sys/sysctl.h> 80 #include <sys/sysent.h> 81 #include <sys/syslog.h> 82 #include <sys/sysproto.h> 83 #include <sys/timers.h> 84 #include <sys/unistd.h> 85 #include <sys/wait.h> 86 #include <vm/vm.h> 87 #include <vm/vm_extern.h> 88 #include <vm/uma.h> 89 90 #include <sys/jail.h> 91 92 #include <machine/cpu.h> 93 94 #include <security/audit/audit.h> 95 96 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */ 97 98 SDT_PROVIDER_DECLARE(proc); 99 SDT_PROBE_DEFINE3(proc, , , signal__send, 100 "struct thread *", "struct proc *", "int"); 101 SDT_PROBE_DEFINE2(proc, , , signal__clear, 102 "int", "ksiginfo_t *"); 103 SDT_PROBE_DEFINE3(proc, , , signal__discard, 104 "struct thread *", "struct proc *", "int"); 105 106 static int coredump(struct thread *); 107 static int killpg1(struct thread *td, int sig, int pgid, int all, 108 ksiginfo_t *ksi); 109 static int issignal(struct thread *td); 110 static void reschedule_signals(struct proc *p, sigset_t block, int flags); 111 static int sigprop(int sig); 112 static void tdsigwakeup(struct thread *, int, sig_t, int); 113 static int sig_suspend_threads(struct thread *, struct proc *, int); 114 static int filt_sigattach(struct knote *kn); 115 static void filt_sigdetach(struct knote *kn); 116 static int filt_signal(struct knote *kn, long hint); 117 static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock); 118 static void sigqueue_start(void); 119 120 static uma_zone_t ksiginfo_zone = NULL; 121 struct filterops sig_filtops = { 122 .f_isfd = 0, 123 .f_attach = filt_sigattach, 124 .f_detach = filt_sigdetach, 125 .f_event = filt_signal, 126 }; 127 128 static int kern_logsigexit = 1; 129 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 130 &kern_logsigexit, 0, 131 "Log processes quitting on abnormal signals to syslog(3)"); 132 133 static int kern_forcesigexit = 1; 134 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW, 135 &kern_forcesigexit, 0, "Force trap signal to be handled"); 136 137 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 138 "POSIX real time signal"); 139 140 static int max_pending_per_proc = 128; 141 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW, 142 &max_pending_per_proc, 0, "Max pending signals per proc"); 143 144 static int preallocate_siginfo = 1024; 145 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN, 146 &preallocate_siginfo, 0, "Preallocated signal memory size"); 147 148 static int signal_overflow = 0; 149 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD, 150 &signal_overflow, 0, "Number of signals overflew"); 151 152 static int signal_alloc_fail = 0; 153 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD, 154 &signal_alloc_fail, 0, "signals failed to be allocated"); 155 156 static int kern_lognosys = 0; 157 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0, 158 "Log invalid syscalls"); 159 160 __read_frequently bool sigfastblock_fetch_always = false; 161 SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN, 162 &sigfastblock_fetch_always, 0, 163 "Fetch sigfastblock word on each syscall entry for proper " 164 "blocking semantic"); 165 166 static bool kern_sig_discard_ign = true; 167 SYSCTL_BOOL(_kern, OID_AUTO, sig_discard_ign, CTLFLAG_RWTUN, 168 &kern_sig_discard_ign, 0, 169 "Discard ignored signals on delivery, otherwise queue them to " 170 "the target queue"); 171 172 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL); 173 174 /* 175 * Policy -- Can ucred cr1 send SIGIO to process cr2? 176 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG 177 * in the right situations. 178 */ 179 #define CANSIGIO(cr1, cr2) \ 180 ((cr1)->cr_uid == 0 || \ 181 (cr1)->cr_ruid == (cr2)->cr_ruid || \ 182 (cr1)->cr_uid == (cr2)->cr_ruid || \ 183 (cr1)->cr_ruid == (cr2)->cr_uid || \ 184 (cr1)->cr_uid == (cr2)->cr_uid) 185 186 static int sugid_coredump; 187 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN, 188 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core"); 189 190 static int capmode_coredump; 191 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN, 192 &capmode_coredump, 0, "Allow processes in capability mode to dump core"); 193 194 static int do_coredump = 1; 195 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 196 &do_coredump, 0, "Enable/Disable coredumps"); 197 198 static int set_core_nodump_flag = 0; 199 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag, 200 0, "Enable setting the NODUMP flag on coredump files"); 201 202 static int coredump_devctl = 0; 203 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl, 204 0, "Generate a devctl notification when processes coredump"); 205 206 /* 207 * Signal properties and actions. 208 * The array below categorizes the signals and their default actions 209 * according to the following properties: 210 */ 211 #define SIGPROP_KILL 0x01 /* terminates process by default */ 212 #define SIGPROP_CORE 0x02 /* ditto and coredumps */ 213 #define SIGPROP_STOP 0x04 /* suspend process */ 214 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */ 215 #define SIGPROP_IGNORE 0x10 /* ignore by default */ 216 #define SIGPROP_CONT 0x20 /* continue if suspended */ 217 218 static int sigproptbl[NSIG] = { 219 [SIGHUP] = SIGPROP_KILL, 220 [SIGINT] = SIGPROP_KILL, 221 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE, 222 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE, 223 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE, 224 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE, 225 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE, 226 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE, 227 [SIGKILL] = SIGPROP_KILL, 228 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE, 229 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE, 230 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE, 231 [SIGPIPE] = SIGPROP_KILL, 232 [SIGALRM] = SIGPROP_KILL, 233 [SIGTERM] = SIGPROP_KILL, 234 [SIGURG] = SIGPROP_IGNORE, 235 [SIGSTOP] = SIGPROP_STOP, 236 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP, 237 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT, 238 [SIGCHLD] = SIGPROP_IGNORE, 239 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP, 240 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP, 241 [SIGIO] = SIGPROP_IGNORE, 242 [SIGXCPU] = SIGPROP_KILL, 243 [SIGXFSZ] = SIGPROP_KILL, 244 [SIGVTALRM] = SIGPROP_KILL, 245 [SIGPROF] = SIGPROP_KILL, 246 [SIGWINCH] = SIGPROP_IGNORE, 247 [SIGINFO] = SIGPROP_IGNORE, 248 [SIGUSR1] = SIGPROP_KILL, 249 [SIGUSR2] = SIGPROP_KILL, 250 }; 251 252 sigset_t fastblock_mask; 253 254 static void 255 sigqueue_start(void) 256 { 257 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t), 258 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 259 uma_prealloc(ksiginfo_zone, preallocate_siginfo); 260 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS); 261 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1); 262 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc); 263 SIGFILLSET(fastblock_mask); 264 SIG_CANTMASK(fastblock_mask); 265 } 266 267 ksiginfo_t * 268 ksiginfo_alloc(int wait) 269 { 270 int flags; 271 272 flags = M_ZERO; 273 if (! wait) 274 flags |= M_NOWAIT; 275 if (ksiginfo_zone != NULL) 276 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags)); 277 return (NULL); 278 } 279 280 void 281 ksiginfo_free(ksiginfo_t *ksi) 282 { 283 uma_zfree(ksiginfo_zone, ksi); 284 } 285 286 static __inline int 287 ksiginfo_tryfree(ksiginfo_t *ksi) 288 { 289 if (!(ksi->ksi_flags & KSI_EXT)) { 290 uma_zfree(ksiginfo_zone, ksi); 291 return (1); 292 } 293 return (0); 294 } 295 296 void 297 sigqueue_init(sigqueue_t *list, struct proc *p) 298 { 299 SIGEMPTYSET(list->sq_signals); 300 SIGEMPTYSET(list->sq_kill); 301 SIGEMPTYSET(list->sq_ptrace); 302 TAILQ_INIT(&list->sq_list); 303 list->sq_proc = p; 304 list->sq_flags = SQ_INIT; 305 } 306 307 /* 308 * Get a signal's ksiginfo. 309 * Return: 310 * 0 - signal not found 311 * others - signal number 312 */ 313 static int 314 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si) 315 { 316 struct proc *p = sq->sq_proc; 317 struct ksiginfo *ksi, *next; 318 int count = 0; 319 320 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 321 322 if (!SIGISMEMBER(sq->sq_signals, signo)) 323 return (0); 324 325 if (SIGISMEMBER(sq->sq_ptrace, signo)) { 326 count++; 327 SIGDELSET(sq->sq_ptrace, signo); 328 si->ksi_flags |= KSI_PTRACE; 329 } 330 if (SIGISMEMBER(sq->sq_kill, signo)) { 331 count++; 332 if (count == 1) 333 SIGDELSET(sq->sq_kill, signo); 334 } 335 336 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 337 if (ksi->ksi_signo == signo) { 338 if (count == 0) { 339 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 340 ksi->ksi_sigq = NULL; 341 ksiginfo_copy(ksi, si); 342 if (ksiginfo_tryfree(ksi) && p != NULL) 343 p->p_pendingcnt--; 344 } 345 if (++count > 1) 346 break; 347 } 348 } 349 350 if (count <= 1) 351 SIGDELSET(sq->sq_signals, signo); 352 si->ksi_signo = signo; 353 return (signo); 354 } 355 356 void 357 sigqueue_take(ksiginfo_t *ksi) 358 { 359 struct ksiginfo *kp; 360 struct proc *p; 361 sigqueue_t *sq; 362 363 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL) 364 return; 365 366 p = sq->sq_proc; 367 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 368 ksi->ksi_sigq = NULL; 369 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL) 370 p->p_pendingcnt--; 371 372 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL; 373 kp = TAILQ_NEXT(kp, ksi_link)) { 374 if (kp->ksi_signo == ksi->ksi_signo) 375 break; 376 } 377 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) && 378 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo)) 379 SIGDELSET(sq->sq_signals, ksi->ksi_signo); 380 } 381 382 static int 383 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si) 384 { 385 struct proc *p = sq->sq_proc; 386 struct ksiginfo *ksi; 387 int ret = 0; 388 389 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 390 391 /* 392 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path 393 * for these signals. 394 */ 395 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) { 396 SIGADDSET(sq->sq_kill, signo); 397 goto out_set_bit; 398 } 399 400 /* directly insert the ksi, don't copy it */ 401 if (si->ksi_flags & KSI_INS) { 402 if (si->ksi_flags & KSI_HEAD) 403 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link); 404 else 405 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link); 406 si->ksi_sigq = sq; 407 goto out_set_bit; 408 } 409 410 if (__predict_false(ksiginfo_zone == NULL)) { 411 SIGADDSET(sq->sq_kill, signo); 412 goto out_set_bit; 413 } 414 415 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) { 416 signal_overflow++; 417 ret = EAGAIN; 418 } else if ((ksi = ksiginfo_alloc(0)) == NULL) { 419 signal_alloc_fail++; 420 ret = EAGAIN; 421 } else { 422 if (p != NULL) 423 p->p_pendingcnt++; 424 ksiginfo_copy(si, ksi); 425 ksi->ksi_signo = signo; 426 if (si->ksi_flags & KSI_HEAD) 427 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link); 428 else 429 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link); 430 ksi->ksi_sigq = sq; 431 } 432 433 if (ret != 0) { 434 if ((si->ksi_flags & KSI_PTRACE) != 0) { 435 SIGADDSET(sq->sq_ptrace, signo); 436 ret = 0; 437 goto out_set_bit; 438 } else if ((si->ksi_flags & KSI_TRAP) != 0 || 439 (si->ksi_flags & KSI_SIGQ) == 0) { 440 SIGADDSET(sq->sq_kill, signo); 441 ret = 0; 442 goto out_set_bit; 443 } 444 return (ret); 445 } 446 447 out_set_bit: 448 SIGADDSET(sq->sq_signals, signo); 449 return (ret); 450 } 451 452 void 453 sigqueue_flush(sigqueue_t *sq) 454 { 455 struct proc *p = sq->sq_proc; 456 ksiginfo_t *ksi; 457 458 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 459 460 if (p != NULL) 461 PROC_LOCK_ASSERT(p, MA_OWNED); 462 463 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) { 464 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 465 ksi->ksi_sigq = NULL; 466 if (ksiginfo_tryfree(ksi) && p != NULL) 467 p->p_pendingcnt--; 468 } 469 470 SIGEMPTYSET(sq->sq_signals); 471 SIGEMPTYSET(sq->sq_kill); 472 SIGEMPTYSET(sq->sq_ptrace); 473 } 474 475 static void 476 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set) 477 { 478 sigset_t tmp; 479 struct proc *p1, *p2; 480 ksiginfo_t *ksi, *next; 481 482 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited")); 483 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited")); 484 p1 = src->sq_proc; 485 p2 = dst->sq_proc; 486 /* Move siginfo to target list */ 487 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) { 488 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 489 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link); 490 if (p1 != NULL) 491 p1->p_pendingcnt--; 492 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link); 493 ksi->ksi_sigq = dst; 494 if (p2 != NULL) 495 p2->p_pendingcnt++; 496 } 497 } 498 499 /* Move pending bits to target list */ 500 tmp = src->sq_kill; 501 SIGSETAND(tmp, *set); 502 SIGSETOR(dst->sq_kill, tmp); 503 SIGSETNAND(src->sq_kill, tmp); 504 505 tmp = src->sq_ptrace; 506 SIGSETAND(tmp, *set); 507 SIGSETOR(dst->sq_ptrace, tmp); 508 SIGSETNAND(src->sq_ptrace, tmp); 509 510 tmp = src->sq_signals; 511 SIGSETAND(tmp, *set); 512 SIGSETOR(dst->sq_signals, tmp); 513 SIGSETNAND(src->sq_signals, tmp); 514 } 515 516 #if 0 517 static void 518 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo) 519 { 520 sigset_t set; 521 522 SIGEMPTYSET(set); 523 SIGADDSET(set, signo); 524 sigqueue_move_set(src, dst, &set); 525 } 526 #endif 527 528 static void 529 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set) 530 { 531 struct proc *p = sq->sq_proc; 532 ksiginfo_t *ksi, *next; 533 534 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited")); 535 536 /* Remove siginfo queue */ 537 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 538 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 539 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 540 ksi->ksi_sigq = NULL; 541 if (ksiginfo_tryfree(ksi) && p != NULL) 542 p->p_pendingcnt--; 543 } 544 } 545 SIGSETNAND(sq->sq_kill, *set); 546 SIGSETNAND(sq->sq_ptrace, *set); 547 SIGSETNAND(sq->sq_signals, *set); 548 } 549 550 void 551 sigqueue_delete(sigqueue_t *sq, int signo) 552 { 553 sigset_t set; 554 555 SIGEMPTYSET(set); 556 SIGADDSET(set, signo); 557 sigqueue_delete_set(sq, &set); 558 } 559 560 /* Remove a set of signals for a process */ 561 static void 562 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set) 563 { 564 sigqueue_t worklist; 565 struct thread *td0; 566 567 PROC_LOCK_ASSERT(p, MA_OWNED); 568 569 sigqueue_init(&worklist, NULL); 570 sigqueue_move_set(&p->p_sigqueue, &worklist, set); 571 572 FOREACH_THREAD_IN_PROC(p, td0) 573 sigqueue_move_set(&td0->td_sigqueue, &worklist, set); 574 575 sigqueue_flush(&worklist); 576 } 577 578 void 579 sigqueue_delete_proc(struct proc *p, int signo) 580 { 581 sigset_t set; 582 583 SIGEMPTYSET(set); 584 SIGADDSET(set, signo); 585 sigqueue_delete_set_proc(p, &set); 586 } 587 588 static void 589 sigqueue_delete_stopmask_proc(struct proc *p) 590 { 591 sigset_t set; 592 593 SIGEMPTYSET(set); 594 SIGADDSET(set, SIGSTOP); 595 SIGADDSET(set, SIGTSTP); 596 SIGADDSET(set, SIGTTIN); 597 SIGADDSET(set, SIGTTOU); 598 sigqueue_delete_set_proc(p, &set); 599 } 600 601 /* 602 * Determine signal that should be delivered to thread td, the current 603 * thread, 0 if none. If there is a pending stop signal with default 604 * action, the process stops in issignal(). 605 */ 606 int 607 cursig(struct thread *td) 608 { 609 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 610 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED); 611 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 612 return (SIGPENDING(td) ? issignal(td) : 0); 613 } 614 615 /* 616 * Arrange for ast() to handle unmasked pending signals on return to user 617 * mode. This must be called whenever a signal is added to td_sigqueue or 618 * unmasked in td_sigmask. 619 */ 620 void 621 signotify(struct thread *td) 622 { 623 624 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 625 626 if (SIGPENDING(td)) { 627 thread_lock(td); 628 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING; 629 thread_unlock(td); 630 } 631 } 632 633 /* 634 * Returns 1 (true) if altstack is configured for the thread, and the 635 * passed stack bottom address falls into the altstack range. Handles 636 * the 43 compat special case where the alt stack size is zero. 637 */ 638 int 639 sigonstack(size_t sp) 640 { 641 struct thread *td; 642 643 td = curthread; 644 if ((td->td_pflags & TDP_ALTSTACK) == 0) 645 return (0); 646 #if defined(COMPAT_43) 647 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0) 648 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0); 649 #endif 650 return (sp >= (size_t)td->td_sigstk.ss_sp && 651 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp); 652 } 653 654 static __inline int 655 sigprop(int sig) 656 { 657 658 if (sig > 0 && sig < nitems(sigproptbl)) 659 return (sigproptbl[sig]); 660 return (0); 661 } 662 663 int 664 sig_ffs(sigset_t *set) 665 { 666 int i; 667 668 for (i = 0; i < _SIG_WORDS; i++) 669 if (set->__bits[i]) 670 return (ffs(set->__bits[i]) + (i * 32)); 671 return (0); 672 } 673 674 static bool 675 sigact_flag_test(const struct sigaction *act, int flag) 676 { 677 678 /* 679 * SA_SIGINFO is reset when signal disposition is set to 680 * ignore or default. Other flags are kept according to user 681 * settings. 682 */ 683 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO || 684 ((__sighandler_t *)act->sa_sigaction != SIG_IGN && 685 (__sighandler_t *)act->sa_sigaction != SIG_DFL))); 686 } 687 688 /* 689 * kern_sigaction 690 * sigaction 691 * freebsd4_sigaction 692 * osigaction 693 */ 694 int 695 kern_sigaction(struct thread *td, int sig, const struct sigaction *act, 696 struct sigaction *oact, int flags) 697 { 698 struct sigacts *ps; 699 struct proc *p = td->td_proc; 700 701 if (!_SIG_VALID(sig)) 702 return (EINVAL); 703 if (act != NULL && act->sa_handler != SIG_DFL && 704 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK | 705 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | 706 SA_NOCLDWAIT | SA_SIGINFO)) != 0) 707 return (EINVAL); 708 709 PROC_LOCK(p); 710 ps = p->p_sigacts; 711 mtx_lock(&ps->ps_mtx); 712 if (oact) { 713 memset(oact, 0, sizeof(*oact)); 714 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 715 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 716 oact->sa_flags |= SA_ONSTACK; 717 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 718 oact->sa_flags |= SA_RESTART; 719 if (SIGISMEMBER(ps->ps_sigreset, sig)) 720 oact->sa_flags |= SA_RESETHAND; 721 if (SIGISMEMBER(ps->ps_signodefer, sig)) 722 oact->sa_flags |= SA_NODEFER; 723 if (SIGISMEMBER(ps->ps_siginfo, sig)) { 724 oact->sa_flags |= SA_SIGINFO; 725 oact->sa_sigaction = 726 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)]; 727 } else 728 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 729 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP) 730 oact->sa_flags |= SA_NOCLDSTOP; 731 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT) 732 oact->sa_flags |= SA_NOCLDWAIT; 733 } 734 if (act) { 735 if ((sig == SIGKILL || sig == SIGSTOP) && 736 act->sa_handler != SIG_DFL) { 737 mtx_unlock(&ps->ps_mtx); 738 PROC_UNLOCK(p); 739 return (EINVAL); 740 } 741 742 /* 743 * Change setting atomically. 744 */ 745 746 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 747 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 748 if (sigact_flag_test(act, SA_SIGINFO)) { 749 ps->ps_sigact[_SIG_IDX(sig)] = 750 (__sighandler_t *)act->sa_sigaction; 751 SIGADDSET(ps->ps_siginfo, sig); 752 } else { 753 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 754 SIGDELSET(ps->ps_siginfo, sig); 755 } 756 if (!sigact_flag_test(act, SA_RESTART)) 757 SIGADDSET(ps->ps_sigintr, sig); 758 else 759 SIGDELSET(ps->ps_sigintr, sig); 760 if (sigact_flag_test(act, SA_ONSTACK)) 761 SIGADDSET(ps->ps_sigonstack, sig); 762 else 763 SIGDELSET(ps->ps_sigonstack, sig); 764 if (sigact_flag_test(act, SA_RESETHAND)) 765 SIGADDSET(ps->ps_sigreset, sig); 766 else 767 SIGDELSET(ps->ps_sigreset, sig); 768 if (sigact_flag_test(act, SA_NODEFER)) 769 SIGADDSET(ps->ps_signodefer, sig); 770 else 771 SIGDELSET(ps->ps_signodefer, sig); 772 if (sig == SIGCHLD) { 773 if (act->sa_flags & SA_NOCLDSTOP) 774 ps->ps_flag |= PS_NOCLDSTOP; 775 else 776 ps->ps_flag &= ~PS_NOCLDSTOP; 777 if (act->sa_flags & SA_NOCLDWAIT) { 778 /* 779 * Paranoia: since SA_NOCLDWAIT is implemented 780 * by reparenting the dying child to PID 1 (and 781 * trust it to reap the zombie), PID 1 itself 782 * is forbidden to set SA_NOCLDWAIT. 783 */ 784 if (p->p_pid == 1) 785 ps->ps_flag &= ~PS_NOCLDWAIT; 786 else 787 ps->ps_flag |= PS_NOCLDWAIT; 788 } else 789 ps->ps_flag &= ~PS_NOCLDWAIT; 790 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 791 ps->ps_flag |= PS_CLDSIGIGN; 792 else 793 ps->ps_flag &= ~PS_CLDSIGIGN; 794 } 795 /* 796 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 797 * and for signals set to SIG_DFL where the default is to 798 * ignore. However, don't put SIGCONT in ps_sigignore, as we 799 * have to restart the process. 800 */ 801 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 802 (sigprop(sig) & SIGPROP_IGNORE && 803 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 804 /* never to be seen again */ 805 sigqueue_delete_proc(p, sig); 806 if (sig != SIGCONT) 807 /* easier in psignal */ 808 SIGADDSET(ps->ps_sigignore, sig); 809 SIGDELSET(ps->ps_sigcatch, sig); 810 } else { 811 SIGDELSET(ps->ps_sigignore, sig); 812 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 813 SIGDELSET(ps->ps_sigcatch, sig); 814 else 815 SIGADDSET(ps->ps_sigcatch, sig); 816 } 817 #ifdef COMPAT_FREEBSD4 818 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 819 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 820 (flags & KSA_FREEBSD4) == 0) 821 SIGDELSET(ps->ps_freebsd4, sig); 822 else 823 SIGADDSET(ps->ps_freebsd4, sig); 824 #endif 825 #ifdef COMPAT_43 826 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 827 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 828 (flags & KSA_OSIGSET) == 0) 829 SIGDELSET(ps->ps_osigset, sig); 830 else 831 SIGADDSET(ps->ps_osigset, sig); 832 #endif 833 } 834 mtx_unlock(&ps->ps_mtx); 835 PROC_UNLOCK(p); 836 return (0); 837 } 838 839 #ifndef _SYS_SYSPROTO_H_ 840 struct sigaction_args { 841 int sig; 842 struct sigaction *act; 843 struct sigaction *oact; 844 }; 845 #endif 846 int 847 sys_sigaction(struct thread *td, struct sigaction_args *uap) 848 { 849 struct sigaction act, oact; 850 struct sigaction *actp, *oactp; 851 int error; 852 853 actp = (uap->act != NULL) ? &act : NULL; 854 oactp = (uap->oact != NULL) ? &oact : NULL; 855 if (actp) { 856 error = copyin(uap->act, actp, sizeof(act)); 857 if (error) 858 return (error); 859 } 860 error = kern_sigaction(td, uap->sig, actp, oactp, 0); 861 if (oactp && !error) 862 error = copyout(oactp, uap->oact, sizeof(oact)); 863 return (error); 864 } 865 866 #ifdef COMPAT_FREEBSD4 867 #ifndef _SYS_SYSPROTO_H_ 868 struct freebsd4_sigaction_args { 869 int sig; 870 struct sigaction *act; 871 struct sigaction *oact; 872 }; 873 #endif 874 int 875 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap) 876 { 877 struct sigaction act, oact; 878 struct sigaction *actp, *oactp; 879 int error; 880 881 actp = (uap->act != NULL) ? &act : NULL; 882 oactp = (uap->oact != NULL) ? &oact : NULL; 883 if (actp) { 884 error = copyin(uap->act, actp, sizeof(act)); 885 if (error) 886 return (error); 887 } 888 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4); 889 if (oactp && !error) 890 error = copyout(oactp, uap->oact, sizeof(oact)); 891 return (error); 892 } 893 #endif /* COMAPT_FREEBSD4 */ 894 895 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 896 #ifndef _SYS_SYSPROTO_H_ 897 struct osigaction_args { 898 int signum; 899 struct osigaction *nsa; 900 struct osigaction *osa; 901 }; 902 #endif 903 int 904 osigaction(struct thread *td, struct osigaction_args *uap) 905 { 906 struct osigaction sa; 907 struct sigaction nsa, osa; 908 struct sigaction *nsap, *osap; 909 int error; 910 911 if (uap->signum <= 0 || uap->signum >= ONSIG) 912 return (EINVAL); 913 914 nsap = (uap->nsa != NULL) ? &nsa : NULL; 915 osap = (uap->osa != NULL) ? &osa : NULL; 916 917 if (nsap) { 918 error = copyin(uap->nsa, &sa, sizeof(sa)); 919 if (error) 920 return (error); 921 nsap->sa_handler = sa.sa_handler; 922 nsap->sa_flags = sa.sa_flags; 923 OSIG2SIG(sa.sa_mask, nsap->sa_mask); 924 } 925 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 926 if (osap && !error) { 927 sa.sa_handler = osap->sa_handler; 928 sa.sa_flags = osap->sa_flags; 929 SIG2OSIG(osap->sa_mask, sa.sa_mask); 930 error = copyout(&sa, uap->osa, sizeof(sa)); 931 } 932 return (error); 933 } 934 935 #if !defined(__i386__) 936 /* Avoid replicating the same stub everywhere */ 937 int 938 osigreturn(struct thread *td, struct osigreturn_args *uap) 939 { 940 941 return (nosys(td, (struct nosys_args *)uap)); 942 } 943 #endif 944 #endif /* COMPAT_43 */ 945 946 /* 947 * Initialize signal state for process 0; 948 * set to ignore signals that are ignored by default. 949 */ 950 void 951 siginit(struct proc *p) 952 { 953 int i; 954 struct sigacts *ps; 955 956 PROC_LOCK(p); 957 ps = p->p_sigacts; 958 mtx_lock(&ps->ps_mtx); 959 for (i = 1; i <= NSIG; i++) { 960 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) { 961 SIGADDSET(ps->ps_sigignore, i); 962 } 963 } 964 mtx_unlock(&ps->ps_mtx); 965 PROC_UNLOCK(p); 966 } 967 968 /* 969 * Reset specified signal to the default disposition. 970 */ 971 static void 972 sigdflt(struct sigacts *ps, int sig) 973 { 974 975 mtx_assert(&ps->ps_mtx, MA_OWNED); 976 SIGDELSET(ps->ps_sigcatch, sig); 977 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT) 978 SIGADDSET(ps->ps_sigignore, sig); 979 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 980 SIGDELSET(ps->ps_siginfo, sig); 981 } 982 983 /* 984 * Reset signals for an exec of the specified process. 985 */ 986 void 987 execsigs(struct proc *p) 988 { 989 struct sigacts *ps; 990 struct thread *td; 991 992 /* 993 * Reset caught signals. Held signals remain held 994 * through td_sigmask (unless they were caught, 995 * and are now ignored by default). 996 */ 997 PROC_LOCK_ASSERT(p, MA_OWNED); 998 ps = p->p_sigacts; 999 mtx_lock(&ps->ps_mtx); 1000 sig_drop_caught(p); 1001 1002 /* 1003 * Reset stack state to the user stack. 1004 * Clear set of signals caught on the signal stack. 1005 */ 1006 td = curthread; 1007 MPASS(td->td_proc == p); 1008 td->td_sigstk.ss_flags = SS_DISABLE; 1009 td->td_sigstk.ss_size = 0; 1010 td->td_sigstk.ss_sp = 0; 1011 td->td_pflags &= ~TDP_ALTSTACK; 1012 /* 1013 * Reset no zombies if child dies flag as Solaris does. 1014 */ 1015 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 1016 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 1017 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 1018 mtx_unlock(&ps->ps_mtx); 1019 } 1020 1021 /* 1022 * kern_sigprocmask() 1023 * 1024 * Manipulate signal mask. 1025 */ 1026 int 1027 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset, 1028 int flags) 1029 { 1030 sigset_t new_block, oset1; 1031 struct proc *p; 1032 int error; 1033 1034 p = td->td_proc; 1035 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0) 1036 PROC_LOCK_ASSERT(p, MA_OWNED); 1037 else 1038 PROC_LOCK(p); 1039 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 1040 ? MA_OWNED : MA_NOTOWNED); 1041 if (oset != NULL) 1042 *oset = td->td_sigmask; 1043 1044 error = 0; 1045 if (set != NULL) { 1046 switch (how) { 1047 case SIG_BLOCK: 1048 SIG_CANTMASK(*set); 1049 oset1 = td->td_sigmask; 1050 SIGSETOR(td->td_sigmask, *set); 1051 new_block = td->td_sigmask; 1052 SIGSETNAND(new_block, oset1); 1053 break; 1054 case SIG_UNBLOCK: 1055 SIGSETNAND(td->td_sigmask, *set); 1056 signotify(td); 1057 goto out; 1058 case SIG_SETMASK: 1059 SIG_CANTMASK(*set); 1060 oset1 = td->td_sigmask; 1061 if (flags & SIGPROCMASK_OLD) 1062 SIGSETLO(td->td_sigmask, *set); 1063 else 1064 td->td_sigmask = *set; 1065 new_block = td->td_sigmask; 1066 SIGSETNAND(new_block, oset1); 1067 signotify(td); 1068 break; 1069 default: 1070 error = EINVAL; 1071 goto out; 1072 } 1073 1074 /* 1075 * The new_block set contains signals that were not previously 1076 * blocked, but are blocked now. 1077 * 1078 * In case we block any signal that was not previously blocked 1079 * for td, and process has the signal pending, try to schedule 1080 * signal delivery to some thread that does not block the 1081 * signal, possibly waking it up. 1082 */ 1083 if (p->p_numthreads != 1) 1084 reschedule_signals(p, new_block, flags); 1085 } 1086 1087 out: 1088 if (!(flags & SIGPROCMASK_PROC_LOCKED)) 1089 PROC_UNLOCK(p); 1090 return (error); 1091 } 1092 1093 #ifndef _SYS_SYSPROTO_H_ 1094 struct sigprocmask_args { 1095 int how; 1096 const sigset_t *set; 1097 sigset_t *oset; 1098 }; 1099 #endif 1100 int 1101 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap) 1102 { 1103 sigset_t set, oset; 1104 sigset_t *setp, *osetp; 1105 int error; 1106 1107 setp = (uap->set != NULL) ? &set : NULL; 1108 osetp = (uap->oset != NULL) ? &oset : NULL; 1109 if (setp) { 1110 error = copyin(uap->set, setp, sizeof(set)); 1111 if (error) 1112 return (error); 1113 } 1114 error = kern_sigprocmask(td, uap->how, setp, osetp, 0); 1115 if (osetp && !error) { 1116 error = copyout(osetp, uap->oset, sizeof(oset)); 1117 } 1118 return (error); 1119 } 1120 1121 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1122 #ifndef _SYS_SYSPROTO_H_ 1123 struct osigprocmask_args { 1124 int how; 1125 osigset_t mask; 1126 }; 1127 #endif 1128 int 1129 osigprocmask(struct thread *td, struct osigprocmask_args *uap) 1130 { 1131 sigset_t set, oset; 1132 int error; 1133 1134 OSIG2SIG(uap->mask, set); 1135 error = kern_sigprocmask(td, uap->how, &set, &oset, 1); 1136 SIG2OSIG(oset, td->td_retval[0]); 1137 return (error); 1138 } 1139 #endif /* COMPAT_43 */ 1140 1141 int 1142 sys_sigwait(struct thread *td, struct sigwait_args *uap) 1143 { 1144 ksiginfo_t ksi; 1145 sigset_t set; 1146 int error; 1147 1148 error = copyin(uap->set, &set, sizeof(set)); 1149 if (error) { 1150 td->td_retval[0] = error; 1151 return (0); 1152 } 1153 1154 error = kern_sigtimedwait(td, set, &ksi, NULL); 1155 if (error) { 1156 /* 1157 * sigwait() function shall not return EINTR, but 1158 * the syscall does. Non-ancient libc provides the 1159 * wrapper which hides EINTR. Otherwise, EINTR return 1160 * is used by libthr to handle required cancellation 1161 * point in the sigwait(). 1162 */ 1163 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT) 1164 return (ERESTART); 1165 td->td_retval[0] = error; 1166 return (0); 1167 } 1168 1169 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo)); 1170 td->td_retval[0] = error; 1171 return (0); 1172 } 1173 1174 int 1175 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap) 1176 { 1177 struct timespec ts; 1178 struct timespec *timeout; 1179 sigset_t set; 1180 ksiginfo_t ksi; 1181 int error; 1182 1183 if (uap->timeout) { 1184 error = copyin(uap->timeout, &ts, sizeof(ts)); 1185 if (error) 1186 return (error); 1187 1188 timeout = &ts; 1189 } else 1190 timeout = NULL; 1191 1192 error = copyin(uap->set, &set, sizeof(set)); 1193 if (error) 1194 return (error); 1195 1196 error = kern_sigtimedwait(td, set, &ksi, timeout); 1197 if (error) 1198 return (error); 1199 1200 if (uap->info) 1201 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1202 1203 if (error == 0) 1204 td->td_retval[0] = ksi.ksi_signo; 1205 return (error); 1206 } 1207 1208 int 1209 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap) 1210 { 1211 ksiginfo_t ksi; 1212 sigset_t set; 1213 int error; 1214 1215 error = copyin(uap->set, &set, sizeof(set)); 1216 if (error) 1217 return (error); 1218 1219 error = kern_sigtimedwait(td, set, &ksi, NULL); 1220 if (error) 1221 return (error); 1222 1223 if (uap->info) 1224 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1225 1226 if (error == 0) 1227 td->td_retval[0] = ksi.ksi_signo; 1228 return (error); 1229 } 1230 1231 static void 1232 proc_td_siginfo_capture(struct thread *td, siginfo_t *si) 1233 { 1234 struct thread *thr; 1235 1236 FOREACH_THREAD_IN_PROC(td->td_proc, thr) { 1237 if (thr == td) 1238 thr->td_si = *si; 1239 else 1240 thr->td_si.si_signo = 0; 1241 } 1242 } 1243 1244 int 1245 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi, 1246 struct timespec *timeout) 1247 { 1248 struct sigacts *ps; 1249 sigset_t saved_mask, new_block; 1250 struct proc *p; 1251 int error, sig, timo, timevalid = 0; 1252 struct timespec rts, ets, ts; 1253 struct timeval tv; 1254 bool traced; 1255 1256 p = td->td_proc; 1257 error = 0; 1258 ets.tv_sec = 0; 1259 ets.tv_nsec = 0; 1260 traced = false; 1261 1262 /* Ensure the sigfastblock value is up to date. */ 1263 sigfastblock_fetch(td); 1264 1265 if (timeout != NULL) { 1266 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { 1267 timevalid = 1; 1268 getnanouptime(&rts); 1269 timespecadd(&rts, timeout, &ets); 1270 } 1271 } 1272 ksiginfo_init(ksi); 1273 /* Some signals can not be waited for. */ 1274 SIG_CANTMASK(waitset); 1275 ps = p->p_sigacts; 1276 PROC_LOCK(p); 1277 saved_mask = td->td_sigmask; 1278 SIGSETNAND(td->td_sigmask, waitset); 1279 if ((p->p_sysent->sv_flags & SV_SIG_DISCIGN) != 0 || 1280 !kern_sig_discard_ign) { 1281 thread_lock(td); 1282 td->td_flags |= TDF_SIGWAIT; 1283 thread_unlock(td); 1284 } 1285 for (;;) { 1286 mtx_lock(&ps->ps_mtx); 1287 sig = cursig(td); 1288 mtx_unlock(&ps->ps_mtx); 1289 KASSERT(sig >= 0, ("sig %d", sig)); 1290 if (sig != 0 && SIGISMEMBER(waitset, sig)) { 1291 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 || 1292 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) { 1293 error = 0; 1294 break; 1295 } 1296 } 1297 1298 if (error != 0) 1299 break; 1300 1301 /* 1302 * POSIX says this must be checked after looking for pending 1303 * signals. 1304 */ 1305 if (timeout != NULL) { 1306 if (!timevalid) { 1307 error = EINVAL; 1308 break; 1309 } 1310 getnanouptime(&rts); 1311 if (timespeccmp(&rts, &ets, >=)) { 1312 error = EAGAIN; 1313 break; 1314 } 1315 timespecsub(&ets, &rts, &ts); 1316 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1317 timo = tvtohz(&tv); 1318 } else { 1319 timo = 0; 1320 } 1321 1322 if (traced) { 1323 error = EINTR; 1324 break; 1325 } 1326 1327 error = msleep(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH, 1328 "sigwait", timo); 1329 1330 /* The syscalls can not be restarted. */ 1331 if (error == ERESTART) 1332 error = EINTR; 1333 1334 /* We will calculate timeout by ourself. */ 1335 if (timeout != NULL && error == EAGAIN) 1336 error = 0; 1337 1338 /* 1339 * If PTRACE_SCE or PTRACE_SCX were set after 1340 * userspace entered the syscall, return spurious 1341 * EINTR after wait was done. Only do this as last 1342 * resort after rechecking for possible queued signals 1343 * and expired timeouts. 1344 */ 1345 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0) 1346 traced = true; 1347 } 1348 thread_lock(td); 1349 td->td_flags &= ~TDF_SIGWAIT; 1350 thread_unlock(td); 1351 1352 new_block = saved_mask; 1353 SIGSETNAND(new_block, td->td_sigmask); 1354 td->td_sigmask = saved_mask; 1355 /* 1356 * Fewer signals can be delivered to us, reschedule signal 1357 * notification. 1358 */ 1359 if (p->p_numthreads != 1) 1360 reschedule_signals(p, new_block, 0); 1361 1362 if (error == 0) { 1363 SDT_PROBE2(proc, , , signal__clear, sig, ksi); 1364 1365 if (ksi->ksi_code == SI_TIMER) 1366 itimer_accept(p, ksi->ksi_timerid, ksi); 1367 1368 #ifdef KTRACE 1369 if (KTRPOINT(td, KTR_PSIG)) { 1370 sig_t action; 1371 1372 mtx_lock(&ps->ps_mtx); 1373 action = ps->ps_sigact[_SIG_IDX(sig)]; 1374 mtx_unlock(&ps->ps_mtx); 1375 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code); 1376 } 1377 #endif 1378 if (sig == SIGKILL) { 1379 proc_td_siginfo_capture(td, &ksi->ksi_info); 1380 sigexit(td, sig); 1381 } 1382 } 1383 PROC_UNLOCK(p); 1384 return (error); 1385 } 1386 1387 #ifndef _SYS_SYSPROTO_H_ 1388 struct sigpending_args { 1389 sigset_t *set; 1390 }; 1391 #endif 1392 int 1393 sys_sigpending(struct thread *td, struct sigpending_args *uap) 1394 { 1395 struct proc *p = td->td_proc; 1396 sigset_t pending; 1397 1398 PROC_LOCK(p); 1399 pending = p->p_sigqueue.sq_signals; 1400 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1401 PROC_UNLOCK(p); 1402 return (copyout(&pending, uap->set, sizeof(sigset_t))); 1403 } 1404 1405 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1406 #ifndef _SYS_SYSPROTO_H_ 1407 struct osigpending_args { 1408 int dummy; 1409 }; 1410 #endif 1411 int 1412 osigpending(struct thread *td, struct osigpending_args *uap) 1413 { 1414 struct proc *p = td->td_proc; 1415 sigset_t pending; 1416 1417 PROC_LOCK(p); 1418 pending = p->p_sigqueue.sq_signals; 1419 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1420 PROC_UNLOCK(p); 1421 SIG2OSIG(pending, td->td_retval[0]); 1422 return (0); 1423 } 1424 #endif /* COMPAT_43 */ 1425 1426 #if defined(COMPAT_43) 1427 /* 1428 * Generalized interface signal handler, 4.3-compatible. 1429 */ 1430 #ifndef _SYS_SYSPROTO_H_ 1431 struct osigvec_args { 1432 int signum; 1433 struct sigvec *nsv; 1434 struct sigvec *osv; 1435 }; 1436 #endif 1437 /* ARGSUSED */ 1438 int 1439 osigvec(struct thread *td, struct osigvec_args *uap) 1440 { 1441 struct sigvec vec; 1442 struct sigaction nsa, osa; 1443 struct sigaction *nsap, *osap; 1444 int error; 1445 1446 if (uap->signum <= 0 || uap->signum >= ONSIG) 1447 return (EINVAL); 1448 nsap = (uap->nsv != NULL) ? &nsa : NULL; 1449 osap = (uap->osv != NULL) ? &osa : NULL; 1450 if (nsap) { 1451 error = copyin(uap->nsv, &vec, sizeof(vec)); 1452 if (error) 1453 return (error); 1454 nsap->sa_handler = vec.sv_handler; 1455 OSIG2SIG(vec.sv_mask, nsap->sa_mask); 1456 nsap->sa_flags = vec.sv_flags; 1457 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ 1458 } 1459 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 1460 if (osap && !error) { 1461 vec.sv_handler = osap->sa_handler; 1462 SIG2OSIG(osap->sa_mask, vec.sv_mask); 1463 vec.sv_flags = osap->sa_flags; 1464 vec.sv_flags &= ~SA_NOCLDWAIT; 1465 vec.sv_flags ^= SA_RESTART; 1466 error = copyout(&vec, uap->osv, sizeof(vec)); 1467 } 1468 return (error); 1469 } 1470 1471 #ifndef _SYS_SYSPROTO_H_ 1472 struct osigblock_args { 1473 int mask; 1474 }; 1475 #endif 1476 int 1477 osigblock(struct thread *td, struct osigblock_args *uap) 1478 { 1479 sigset_t set, oset; 1480 1481 OSIG2SIG(uap->mask, set); 1482 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0); 1483 SIG2OSIG(oset, td->td_retval[0]); 1484 return (0); 1485 } 1486 1487 #ifndef _SYS_SYSPROTO_H_ 1488 struct osigsetmask_args { 1489 int mask; 1490 }; 1491 #endif 1492 int 1493 osigsetmask(struct thread *td, struct osigsetmask_args *uap) 1494 { 1495 sigset_t set, oset; 1496 1497 OSIG2SIG(uap->mask, set); 1498 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0); 1499 SIG2OSIG(oset, td->td_retval[0]); 1500 return (0); 1501 } 1502 #endif /* COMPAT_43 */ 1503 1504 /* 1505 * Suspend calling thread until signal, providing mask to be set in the 1506 * meantime. 1507 */ 1508 #ifndef _SYS_SYSPROTO_H_ 1509 struct sigsuspend_args { 1510 const sigset_t *sigmask; 1511 }; 1512 #endif 1513 /* ARGSUSED */ 1514 int 1515 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap) 1516 { 1517 sigset_t mask; 1518 int error; 1519 1520 error = copyin(uap->sigmask, &mask, sizeof(mask)); 1521 if (error) 1522 return (error); 1523 return (kern_sigsuspend(td, mask)); 1524 } 1525 1526 int 1527 kern_sigsuspend(struct thread *td, sigset_t mask) 1528 { 1529 struct proc *p = td->td_proc; 1530 int has_sig, sig; 1531 1532 /* Ensure the sigfastblock value is up to date. */ 1533 sigfastblock_fetch(td); 1534 1535 /* 1536 * When returning from sigsuspend, we want 1537 * the old mask to be restored after the 1538 * signal handler has finished. Thus, we 1539 * save it here and mark the sigacts structure 1540 * to indicate this. 1541 */ 1542 PROC_LOCK(p); 1543 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask, 1544 SIGPROCMASK_PROC_LOCKED); 1545 td->td_pflags |= TDP_OLDMASK; 1546 1547 /* 1548 * Process signals now. Otherwise, we can get spurious wakeup 1549 * due to signal entered process queue, but delivered to other 1550 * thread. But sigsuspend should return only on signal 1551 * delivery. 1552 */ 1553 (p->p_sysent->sv_set_syscall_retval)(td, EINTR); 1554 for (has_sig = 0; !has_sig;) { 1555 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 1556 0) == 0) 1557 /* void */; 1558 thread_suspend_check(0); 1559 mtx_lock(&p->p_sigacts->ps_mtx); 1560 while ((sig = cursig(td)) != 0) { 1561 KASSERT(sig >= 0, ("sig %d", sig)); 1562 has_sig += postsig(sig); 1563 } 1564 mtx_unlock(&p->p_sigacts->ps_mtx); 1565 1566 /* 1567 * If PTRACE_SCE or PTRACE_SCX were set after 1568 * userspace entered the syscall, return spurious 1569 * EINTR. 1570 */ 1571 if ((p->p_ptevents & PTRACE_SYSCALL) != 0) 1572 has_sig += 1; 1573 } 1574 PROC_UNLOCK(p); 1575 td->td_errno = EINTR; 1576 td->td_pflags |= TDP_NERRNO; 1577 return (EJUSTRETURN); 1578 } 1579 1580 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1581 /* 1582 * Compatibility sigsuspend call for old binaries. Note nonstandard calling 1583 * convention: libc stub passes mask, not pointer, to save a copyin. 1584 */ 1585 #ifndef _SYS_SYSPROTO_H_ 1586 struct osigsuspend_args { 1587 osigset_t mask; 1588 }; 1589 #endif 1590 /* ARGSUSED */ 1591 int 1592 osigsuspend(struct thread *td, struct osigsuspend_args *uap) 1593 { 1594 sigset_t mask; 1595 1596 OSIG2SIG(uap->mask, mask); 1597 return (kern_sigsuspend(td, mask)); 1598 } 1599 #endif /* COMPAT_43 */ 1600 1601 #if defined(COMPAT_43) 1602 #ifndef _SYS_SYSPROTO_H_ 1603 struct osigstack_args { 1604 struct sigstack *nss; 1605 struct sigstack *oss; 1606 }; 1607 #endif 1608 /* ARGSUSED */ 1609 int 1610 osigstack(struct thread *td, struct osigstack_args *uap) 1611 { 1612 struct sigstack nss, oss; 1613 int error = 0; 1614 1615 if (uap->nss != NULL) { 1616 error = copyin(uap->nss, &nss, sizeof(nss)); 1617 if (error) 1618 return (error); 1619 } 1620 oss.ss_sp = td->td_sigstk.ss_sp; 1621 oss.ss_onstack = sigonstack(cpu_getstack(td)); 1622 if (uap->nss != NULL) { 1623 td->td_sigstk.ss_sp = nss.ss_sp; 1624 td->td_sigstk.ss_size = 0; 1625 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK; 1626 td->td_pflags |= TDP_ALTSTACK; 1627 } 1628 if (uap->oss != NULL) 1629 error = copyout(&oss, uap->oss, sizeof(oss)); 1630 1631 return (error); 1632 } 1633 #endif /* COMPAT_43 */ 1634 1635 #ifndef _SYS_SYSPROTO_H_ 1636 struct sigaltstack_args { 1637 stack_t *ss; 1638 stack_t *oss; 1639 }; 1640 #endif 1641 /* ARGSUSED */ 1642 int 1643 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap) 1644 { 1645 stack_t ss, oss; 1646 int error; 1647 1648 if (uap->ss != NULL) { 1649 error = copyin(uap->ss, &ss, sizeof(ss)); 1650 if (error) 1651 return (error); 1652 } 1653 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL, 1654 (uap->oss != NULL) ? &oss : NULL); 1655 if (error) 1656 return (error); 1657 if (uap->oss != NULL) 1658 error = copyout(&oss, uap->oss, sizeof(stack_t)); 1659 return (error); 1660 } 1661 1662 int 1663 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss) 1664 { 1665 struct proc *p = td->td_proc; 1666 int oonstack; 1667 1668 oonstack = sigonstack(cpu_getstack(td)); 1669 1670 if (oss != NULL) { 1671 *oss = td->td_sigstk; 1672 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK) 1673 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 1674 } 1675 1676 if (ss != NULL) { 1677 if (oonstack) 1678 return (EPERM); 1679 if ((ss->ss_flags & ~SS_DISABLE) != 0) 1680 return (EINVAL); 1681 if (!(ss->ss_flags & SS_DISABLE)) { 1682 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 1683 return (ENOMEM); 1684 1685 td->td_sigstk = *ss; 1686 td->td_pflags |= TDP_ALTSTACK; 1687 } else { 1688 td->td_pflags &= ~TDP_ALTSTACK; 1689 } 1690 } 1691 return (0); 1692 } 1693 1694 struct killpg1_ctx { 1695 struct thread *td; 1696 ksiginfo_t *ksi; 1697 int sig; 1698 bool sent; 1699 bool found; 1700 int ret; 1701 }; 1702 1703 static void 1704 killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg) 1705 { 1706 int err; 1707 1708 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 || 1709 (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW) 1710 return; 1711 PROC_LOCK(p); 1712 err = p_cansignal(arg->td, p, arg->sig); 1713 if (err == 0 && arg->sig != 0) 1714 pksignal(p, arg->sig, arg->ksi); 1715 PROC_UNLOCK(p); 1716 if (err != ESRCH) 1717 arg->found = true; 1718 if (err == 0) 1719 arg->sent = true; 1720 else if (arg->ret == 0 && err != ESRCH && err != EPERM) 1721 arg->ret = err; 1722 } 1723 1724 /* 1725 * Common code for kill process group/broadcast kill. 1726 * cp is calling process. 1727 */ 1728 static int 1729 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi) 1730 { 1731 struct proc *p; 1732 struct pgrp *pgrp; 1733 struct killpg1_ctx arg; 1734 1735 arg.td = td; 1736 arg.ksi = ksi; 1737 arg.sig = sig; 1738 arg.sent = false; 1739 arg.found = false; 1740 arg.ret = 0; 1741 if (all) { 1742 /* 1743 * broadcast 1744 */ 1745 sx_slock(&allproc_lock); 1746 FOREACH_PROC_IN_SYSTEM(p) { 1747 killpg1_sendsig(p, true, &arg); 1748 } 1749 sx_sunlock(&allproc_lock); 1750 } else { 1751 sx_slock(&proctree_lock); 1752 if (pgid == 0) { 1753 /* 1754 * zero pgid means send to my process group. 1755 */ 1756 pgrp = td->td_proc->p_pgrp; 1757 PGRP_LOCK(pgrp); 1758 } else { 1759 pgrp = pgfind(pgid); 1760 if (pgrp == NULL) { 1761 sx_sunlock(&proctree_lock); 1762 return (ESRCH); 1763 } 1764 } 1765 sx_sunlock(&proctree_lock); 1766 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1767 killpg1_sendsig(p, false, &arg); 1768 } 1769 PGRP_UNLOCK(pgrp); 1770 } 1771 MPASS(arg.ret != 0 || arg.found || !arg.sent); 1772 if (arg.ret == 0 && !arg.sent) 1773 arg.ret = arg.found ? EPERM : ESRCH; 1774 return (arg.ret); 1775 } 1776 1777 #ifndef _SYS_SYSPROTO_H_ 1778 struct kill_args { 1779 int pid; 1780 int signum; 1781 }; 1782 #endif 1783 /* ARGSUSED */ 1784 int 1785 sys_kill(struct thread *td, struct kill_args *uap) 1786 { 1787 1788 return (kern_kill(td, uap->pid, uap->signum)); 1789 } 1790 1791 int 1792 kern_kill(struct thread *td, pid_t pid, int signum) 1793 { 1794 ksiginfo_t ksi; 1795 struct proc *p; 1796 int error; 1797 1798 /* 1799 * A process in capability mode can send signals only to himself. 1800 * The main rationale behind this is that abort(3) is implemented as 1801 * kill(getpid(), SIGABRT). 1802 */ 1803 if (IN_CAPABILITY_MODE(td) && pid != td->td_proc->p_pid) 1804 return (ECAPMODE); 1805 1806 AUDIT_ARG_SIGNUM(signum); 1807 AUDIT_ARG_PID(pid); 1808 if ((u_int)signum > _SIG_MAXSIG) 1809 return (EINVAL); 1810 1811 ksiginfo_init(&ksi); 1812 ksi.ksi_signo = signum; 1813 ksi.ksi_code = SI_USER; 1814 ksi.ksi_pid = td->td_proc->p_pid; 1815 ksi.ksi_uid = td->td_ucred->cr_ruid; 1816 1817 if (pid > 0) { 1818 /* kill single process */ 1819 if ((p = pfind_any(pid)) == NULL) 1820 return (ESRCH); 1821 AUDIT_ARG_PROCESS(p); 1822 error = p_cansignal(td, p, signum); 1823 if (error == 0 && signum) 1824 pksignal(p, signum, &ksi); 1825 PROC_UNLOCK(p); 1826 return (error); 1827 } 1828 switch (pid) { 1829 case -1: /* broadcast signal */ 1830 return (killpg1(td, signum, 0, 1, &ksi)); 1831 case 0: /* signal own process group */ 1832 return (killpg1(td, signum, 0, 0, &ksi)); 1833 default: /* negative explicit process group */ 1834 return (killpg1(td, signum, -pid, 0, &ksi)); 1835 } 1836 /* NOTREACHED */ 1837 } 1838 1839 int 1840 sys_pdkill(struct thread *td, struct pdkill_args *uap) 1841 { 1842 struct proc *p; 1843 int error; 1844 1845 AUDIT_ARG_SIGNUM(uap->signum); 1846 AUDIT_ARG_FD(uap->fd); 1847 if ((u_int)uap->signum > _SIG_MAXSIG) 1848 return (EINVAL); 1849 1850 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p); 1851 if (error) 1852 return (error); 1853 AUDIT_ARG_PROCESS(p); 1854 error = p_cansignal(td, p, uap->signum); 1855 if (error == 0 && uap->signum) 1856 kern_psignal(p, uap->signum); 1857 PROC_UNLOCK(p); 1858 return (error); 1859 } 1860 1861 #if defined(COMPAT_43) 1862 #ifndef _SYS_SYSPROTO_H_ 1863 struct okillpg_args { 1864 int pgid; 1865 int signum; 1866 }; 1867 #endif 1868 /* ARGSUSED */ 1869 int 1870 okillpg(struct thread *td, struct okillpg_args *uap) 1871 { 1872 ksiginfo_t ksi; 1873 1874 AUDIT_ARG_SIGNUM(uap->signum); 1875 AUDIT_ARG_PID(uap->pgid); 1876 if ((u_int)uap->signum > _SIG_MAXSIG) 1877 return (EINVAL); 1878 1879 ksiginfo_init(&ksi); 1880 ksi.ksi_signo = uap->signum; 1881 ksi.ksi_code = SI_USER; 1882 ksi.ksi_pid = td->td_proc->p_pid; 1883 ksi.ksi_uid = td->td_ucred->cr_ruid; 1884 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi)); 1885 } 1886 #endif /* COMPAT_43 */ 1887 1888 #ifndef _SYS_SYSPROTO_H_ 1889 struct sigqueue_args { 1890 pid_t pid; 1891 int signum; 1892 /* union sigval */ void *value; 1893 }; 1894 #endif 1895 int 1896 sys_sigqueue(struct thread *td, struct sigqueue_args *uap) 1897 { 1898 union sigval sv; 1899 1900 sv.sival_ptr = uap->value; 1901 1902 return (kern_sigqueue(td, uap->pid, uap->signum, &sv)); 1903 } 1904 1905 int 1906 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value) 1907 { 1908 ksiginfo_t ksi; 1909 struct proc *p; 1910 int error; 1911 1912 if ((u_int)signum > _SIG_MAXSIG) 1913 return (EINVAL); 1914 1915 /* 1916 * Specification says sigqueue can only send signal to 1917 * single process. 1918 */ 1919 if (pid <= 0) 1920 return (EINVAL); 1921 1922 if ((p = pfind_any(pid)) == NULL) 1923 return (ESRCH); 1924 error = p_cansignal(td, p, signum); 1925 if (error == 0 && signum != 0) { 1926 ksiginfo_init(&ksi); 1927 ksi.ksi_flags = KSI_SIGQ; 1928 ksi.ksi_signo = signum; 1929 ksi.ksi_code = SI_QUEUE; 1930 ksi.ksi_pid = td->td_proc->p_pid; 1931 ksi.ksi_uid = td->td_ucred->cr_ruid; 1932 ksi.ksi_value = *value; 1933 error = pksignal(p, ksi.ksi_signo, &ksi); 1934 } 1935 PROC_UNLOCK(p); 1936 return (error); 1937 } 1938 1939 /* 1940 * Send a signal to a process group. 1941 */ 1942 void 1943 gsignal(int pgid, int sig, ksiginfo_t *ksi) 1944 { 1945 struct pgrp *pgrp; 1946 1947 if (pgid != 0) { 1948 sx_slock(&proctree_lock); 1949 pgrp = pgfind(pgid); 1950 sx_sunlock(&proctree_lock); 1951 if (pgrp != NULL) { 1952 pgsignal(pgrp, sig, 0, ksi); 1953 PGRP_UNLOCK(pgrp); 1954 } 1955 } 1956 } 1957 1958 /* 1959 * Send a signal to a process group. If checktty is 1, 1960 * limit to members which have a controlling terminal. 1961 */ 1962 void 1963 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi) 1964 { 1965 struct proc *p; 1966 1967 if (pgrp) { 1968 PGRP_LOCK_ASSERT(pgrp, MA_OWNED); 1969 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1970 PROC_LOCK(p); 1971 if (p->p_state == PRS_NORMAL && 1972 (checkctty == 0 || p->p_flag & P_CONTROLT)) 1973 pksignal(p, sig, ksi); 1974 PROC_UNLOCK(p); 1975 } 1976 } 1977 } 1978 1979 /* 1980 * Recalculate the signal mask and reset the signal disposition after 1981 * usermode frame for delivery is formed. Should be called after 1982 * mach-specific routine, because sysent->sv_sendsig() needs correct 1983 * ps_siginfo and signal mask. 1984 */ 1985 static void 1986 postsig_done(int sig, struct thread *td, struct sigacts *ps) 1987 { 1988 sigset_t mask; 1989 1990 mtx_assert(&ps->ps_mtx, MA_OWNED); 1991 td->td_ru.ru_nsignals++; 1992 mask = ps->ps_catchmask[_SIG_IDX(sig)]; 1993 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1994 SIGADDSET(mask, sig); 1995 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, 1996 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); 1997 if (SIGISMEMBER(ps->ps_sigreset, sig)) 1998 sigdflt(ps, sig); 1999 } 2000 2001 /* 2002 * Send a signal caused by a trap to the current thread. If it will be 2003 * caught immediately, deliver it with correct code. Otherwise, post it 2004 * normally. 2005 */ 2006 void 2007 trapsignal(struct thread *td, ksiginfo_t *ksi) 2008 { 2009 struct sigacts *ps; 2010 struct proc *p; 2011 sigset_t sigmask; 2012 int code, sig; 2013 2014 p = td->td_proc; 2015 sig = ksi->ksi_signo; 2016 code = ksi->ksi_code; 2017 KASSERT(_SIG_VALID(sig), ("invalid signal")); 2018 2019 sigfastblock_fetch(td); 2020 PROC_LOCK(p); 2021 ps = p->p_sigacts; 2022 mtx_lock(&ps->ps_mtx); 2023 sigmask = td->td_sigmask; 2024 if (td->td_sigblock_val != 0) 2025 SIGSETOR(sigmask, fastblock_mask); 2026 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) && 2027 !SIGISMEMBER(sigmask, sig)) { 2028 #ifdef KTRACE 2029 if (KTRPOINT(curthread, KTR_PSIG)) 2030 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)], 2031 &td->td_sigmask, code); 2032 #endif 2033 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], 2034 ksi, &td->td_sigmask); 2035 postsig_done(sig, td, ps); 2036 mtx_unlock(&ps->ps_mtx); 2037 } else { 2038 /* 2039 * Avoid a possible infinite loop if the thread 2040 * masking the signal or process is ignoring the 2041 * signal. 2042 */ 2043 if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) || 2044 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) { 2045 SIGDELSET(td->td_sigmask, sig); 2046 SIGDELSET(ps->ps_sigcatch, sig); 2047 SIGDELSET(ps->ps_sigignore, sig); 2048 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2049 td->td_pflags &= ~TDP_SIGFASTBLOCK; 2050 td->td_sigblock_val = 0; 2051 } 2052 mtx_unlock(&ps->ps_mtx); 2053 p->p_sig = sig; /* XXX to verify code */ 2054 tdsendsignal(p, td, sig, ksi); 2055 } 2056 PROC_UNLOCK(p); 2057 } 2058 2059 static struct thread * 2060 sigtd(struct proc *p, int sig, bool fast_sigblock) 2061 { 2062 struct thread *td, *signal_td; 2063 2064 PROC_LOCK_ASSERT(p, MA_OWNED); 2065 MPASS(!fast_sigblock || p == curproc); 2066 2067 /* 2068 * Check if current thread can handle the signal without 2069 * switching context to another thread. 2070 */ 2071 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) && 2072 (!fast_sigblock || curthread->td_sigblock_val == 0)) 2073 return (curthread); 2074 signal_td = NULL; 2075 FOREACH_THREAD_IN_PROC(p, td) { 2076 if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock || 2077 td != curthread || td->td_sigblock_val == 0)) { 2078 signal_td = td; 2079 break; 2080 } 2081 } 2082 if (signal_td == NULL) 2083 signal_td = FIRST_THREAD_IN_PROC(p); 2084 return (signal_td); 2085 } 2086 2087 /* 2088 * Send the signal to the process. If the signal has an action, the action 2089 * is usually performed by the target process rather than the caller; we add 2090 * the signal to the set of pending signals for the process. 2091 * 2092 * Exceptions: 2093 * o When a stop signal is sent to a sleeping process that takes the 2094 * default action, the process is stopped without awakening it. 2095 * o SIGCONT restarts stopped processes (or puts them back to sleep) 2096 * regardless of the signal action (eg, blocked or ignored). 2097 * 2098 * Other ignored signals are discarded immediately. 2099 * 2100 * NB: This function may be entered from the debugger via the "kill" DDB 2101 * command. There is little that can be done to mitigate the possibly messy 2102 * side effects of this unwise possibility. 2103 */ 2104 void 2105 kern_psignal(struct proc *p, int sig) 2106 { 2107 ksiginfo_t ksi; 2108 2109 ksiginfo_init(&ksi); 2110 ksi.ksi_signo = sig; 2111 ksi.ksi_code = SI_KERNEL; 2112 (void) tdsendsignal(p, NULL, sig, &ksi); 2113 } 2114 2115 int 2116 pksignal(struct proc *p, int sig, ksiginfo_t *ksi) 2117 { 2118 2119 return (tdsendsignal(p, NULL, sig, ksi)); 2120 } 2121 2122 /* Utility function for finding a thread to send signal event to. */ 2123 int 2124 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd) 2125 { 2126 struct thread *td; 2127 2128 if (sigev->sigev_notify == SIGEV_THREAD_ID) { 2129 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid); 2130 if (td == NULL) 2131 return (ESRCH); 2132 *ttd = td; 2133 } else { 2134 *ttd = NULL; 2135 PROC_LOCK(p); 2136 } 2137 return (0); 2138 } 2139 2140 void 2141 tdsignal(struct thread *td, int sig) 2142 { 2143 ksiginfo_t ksi; 2144 2145 ksiginfo_init(&ksi); 2146 ksi.ksi_signo = sig; 2147 ksi.ksi_code = SI_KERNEL; 2148 (void) tdsendsignal(td->td_proc, td, sig, &ksi); 2149 } 2150 2151 void 2152 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi) 2153 { 2154 2155 (void) tdsendsignal(td->td_proc, td, sig, ksi); 2156 } 2157 2158 static int 2159 sig_sleepq_abort(struct thread *td, int intrval) 2160 { 2161 THREAD_LOCK_ASSERT(td, MA_OWNED); 2162 2163 if (intrval == 0 && (td->td_flags & TDF_SIGWAIT) == 0) { 2164 thread_unlock(td); 2165 return (0); 2166 } 2167 return (sleepq_abort(td, intrval)); 2168 } 2169 2170 int 2171 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) 2172 { 2173 sig_t action; 2174 sigqueue_t *sigqueue; 2175 int prop; 2176 struct sigacts *ps; 2177 int intrval; 2178 int ret = 0; 2179 int wakeup_swapper; 2180 2181 MPASS(td == NULL || p == td->td_proc); 2182 PROC_LOCK_ASSERT(p, MA_OWNED); 2183 2184 if (!_SIG_VALID(sig)) 2185 panic("%s(): invalid signal %d", __func__, sig); 2186 2187 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__)); 2188 2189 /* 2190 * IEEE Std 1003.1-2001: return success when killing a zombie. 2191 */ 2192 if (p->p_state == PRS_ZOMBIE) { 2193 if (ksi && (ksi->ksi_flags & KSI_INS)) 2194 ksiginfo_tryfree(ksi); 2195 return (ret); 2196 } 2197 2198 ps = p->p_sigacts; 2199 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig); 2200 prop = sigprop(sig); 2201 2202 if (td == NULL) { 2203 td = sigtd(p, sig, false); 2204 sigqueue = &p->p_sigqueue; 2205 } else 2206 sigqueue = &td->td_sigqueue; 2207 2208 SDT_PROBE3(proc, , , signal__send, td, p, sig); 2209 2210 /* 2211 * If the signal is being ignored, then we forget about it 2212 * immediately, except when the target process executes 2213 * sigwait(). (Note: we don't set SIGCONT in ps_sigignore, 2214 * and if it is set to SIG_IGN, action will be SIG_DFL here.) 2215 */ 2216 mtx_lock(&ps->ps_mtx); 2217 if (SIGISMEMBER(ps->ps_sigignore, sig)) { 2218 if (kern_sig_discard_ign && 2219 (p->p_sysent->sv_flags & SV_SIG_DISCIGN) == 0) { 2220 SDT_PROBE3(proc, , , signal__discard, td, p, sig); 2221 2222 mtx_unlock(&ps->ps_mtx); 2223 if (ksi && (ksi->ksi_flags & KSI_INS)) 2224 ksiginfo_tryfree(ksi); 2225 return (ret); 2226 } else { 2227 action = SIG_CATCH; 2228 intrval = 0; 2229 } 2230 } else { 2231 if (SIGISMEMBER(td->td_sigmask, sig)) 2232 action = SIG_HOLD; 2233 else if (SIGISMEMBER(ps->ps_sigcatch, sig)) 2234 action = SIG_CATCH; 2235 else 2236 action = SIG_DFL; 2237 if (SIGISMEMBER(ps->ps_sigintr, sig)) 2238 intrval = EINTR; 2239 else 2240 intrval = ERESTART; 2241 } 2242 mtx_unlock(&ps->ps_mtx); 2243 2244 if (prop & SIGPROP_CONT) 2245 sigqueue_delete_stopmask_proc(p); 2246 else if (prop & SIGPROP_STOP) { 2247 /* 2248 * If sending a tty stop signal to a member of an orphaned 2249 * process group, discard the signal here if the action 2250 * is default; don't stop the process below if sleeping, 2251 * and don't clear any pending SIGCONT. 2252 */ 2253 if ((prop & SIGPROP_TTYSTOP) != 0 && 2254 (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 && 2255 action == SIG_DFL) { 2256 if (ksi && (ksi->ksi_flags & KSI_INS)) 2257 ksiginfo_tryfree(ksi); 2258 return (ret); 2259 } 2260 sigqueue_delete_proc(p, SIGCONT); 2261 if (p->p_flag & P_CONTINUED) { 2262 p->p_flag &= ~P_CONTINUED; 2263 PROC_LOCK(p->p_pptr); 2264 sigqueue_take(p->p_ksi); 2265 PROC_UNLOCK(p->p_pptr); 2266 } 2267 } 2268 2269 ret = sigqueue_add(sigqueue, sig, ksi); 2270 if (ret != 0) 2271 return (ret); 2272 signotify(td); 2273 /* 2274 * Defer further processing for signals which are held, 2275 * except that stopped processes must be continued by SIGCONT. 2276 */ 2277 if (action == SIG_HOLD && 2278 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG))) 2279 return (ret); 2280 2281 wakeup_swapper = 0; 2282 2283 /* 2284 * Some signals have a process-wide effect and a per-thread 2285 * component. Most processing occurs when the process next 2286 * tries to cross the user boundary, however there are some 2287 * times when processing needs to be done immediately, such as 2288 * waking up threads so that they can cross the user boundary. 2289 * We try to do the per-process part here. 2290 */ 2291 if (P_SHOULDSTOP(p)) { 2292 KASSERT(!(p->p_flag & P_WEXIT), 2293 ("signal to stopped but exiting process")); 2294 if (sig == SIGKILL) { 2295 /* 2296 * If traced process is already stopped, 2297 * then no further action is necessary. 2298 */ 2299 if (p->p_flag & P_TRACED) 2300 goto out; 2301 /* 2302 * SIGKILL sets process running. 2303 * It will die elsewhere. 2304 * All threads must be restarted. 2305 */ 2306 p->p_flag &= ~P_STOPPED_SIG; 2307 goto runfast; 2308 } 2309 2310 if (prop & SIGPROP_CONT) { 2311 /* 2312 * If traced process is already stopped, 2313 * then no further action is necessary. 2314 */ 2315 if (p->p_flag & P_TRACED) 2316 goto out; 2317 /* 2318 * If SIGCONT is default (or ignored), we continue the 2319 * process but don't leave the signal in sigqueue as 2320 * it has no further action. If SIGCONT is held, we 2321 * continue the process and leave the signal in 2322 * sigqueue. If the process catches SIGCONT, let it 2323 * handle the signal itself. If it isn't waiting on 2324 * an event, it goes back to run state. 2325 * Otherwise, process goes back to sleep state. 2326 */ 2327 p->p_flag &= ~P_STOPPED_SIG; 2328 PROC_SLOCK(p); 2329 if (p->p_numthreads == p->p_suspcount) { 2330 PROC_SUNLOCK(p); 2331 p->p_flag |= P_CONTINUED; 2332 p->p_xsig = SIGCONT; 2333 PROC_LOCK(p->p_pptr); 2334 childproc_continued(p); 2335 PROC_UNLOCK(p->p_pptr); 2336 PROC_SLOCK(p); 2337 } 2338 if (action == SIG_DFL) { 2339 thread_unsuspend(p); 2340 PROC_SUNLOCK(p); 2341 sigqueue_delete(sigqueue, sig); 2342 goto out_cont; 2343 } 2344 if (action == SIG_CATCH) { 2345 /* 2346 * The process wants to catch it so it needs 2347 * to run at least one thread, but which one? 2348 */ 2349 PROC_SUNLOCK(p); 2350 goto runfast; 2351 } 2352 /* 2353 * The signal is not ignored or caught. 2354 */ 2355 thread_unsuspend(p); 2356 PROC_SUNLOCK(p); 2357 goto out_cont; 2358 } 2359 2360 if (prop & SIGPROP_STOP) { 2361 /* 2362 * If traced process is already stopped, 2363 * then no further action is necessary. 2364 */ 2365 if (p->p_flag & P_TRACED) 2366 goto out; 2367 /* 2368 * Already stopped, don't need to stop again 2369 * (If we did the shell could get confused). 2370 * Just make sure the signal STOP bit set. 2371 */ 2372 p->p_flag |= P_STOPPED_SIG; 2373 sigqueue_delete(sigqueue, sig); 2374 goto out; 2375 } 2376 2377 /* 2378 * All other kinds of signals: 2379 * If a thread is sleeping interruptibly, simulate a 2380 * wakeup so that when it is continued it will be made 2381 * runnable and can look at the signal. However, don't make 2382 * the PROCESS runnable, leave it stopped. 2383 * It may run a bit until it hits a thread_suspend_check(). 2384 */ 2385 PROC_SLOCK(p); 2386 thread_lock(td); 2387 if (TD_CAN_ABORT(td)) 2388 wakeup_swapper = sig_sleepq_abort(td, intrval); 2389 else 2390 thread_unlock(td); 2391 PROC_SUNLOCK(p); 2392 goto out; 2393 /* 2394 * Mutexes are short lived. Threads waiting on them will 2395 * hit thread_suspend_check() soon. 2396 */ 2397 } else if (p->p_state == PRS_NORMAL) { 2398 if (p->p_flag & P_TRACED || action == SIG_CATCH) { 2399 tdsigwakeup(td, sig, action, intrval); 2400 goto out; 2401 } 2402 2403 MPASS(action == SIG_DFL); 2404 2405 if (prop & SIGPROP_STOP) { 2406 if (p->p_flag & (P_PPWAIT|P_WEXIT)) 2407 goto out; 2408 p->p_flag |= P_STOPPED_SIG; 2409 p->p_xsig = sig; 2410 PROC_SLOCK(p); 2411 wakeup_swapper = sig_suspend_threads(td, p, 1); 2412 if (p->p_numthreads == p->p_suspcount) { 2413 /* 2414 * only thread sending signal to another 2415 * process can reach here, if thread is sending 2416 * signal to its process, because thread does 2417 * not suspend itself here, p_numthreads 2418 * should never be equal to p_suspcount. 2419 */ 2420 thread_stopped(p); 2421 PROC_SUNLOCK(p); 2422 sigqueue_delete_proc(p, p->p_xsig); 2423 } else 2424 PROC_SUNLOCK(p); 2425 goto out; 2426 } 2427 } else { 2428 /* Not in "NORMAL" state. discard the signal. */ 2429 sigqueue_delete(sigqueue, sig); 2430 goto out; 2431 } 2432 2433 /* 2434 * The process is not stopped so we need to apply the signal to all the 2435 * running threads. 2436 */ 2437 runfast: 2438 tdsigwakeup(td, sig, action, intrval); 2439 PROC_SLOCK(p); 2440 thread_unsuspend(p); 2441 PROC_SUNLOCK(p); 2442 out_cont: 2443 itimer_proc_continue(p); 2444 kqtimer_proc_continue(p); 2445 out: 2446 /* If we jump here, proc slock should not be owned. */ 2447 PROC_SLOCK_ASSERT(p, MA_NOTOWNED); 2448 if (wakeup_swapper) 2449 kick_proc0(); 2450 2451 return (ret); 2452 } 2453 2454 /* 2455 * The force of a signal has been directed against a single 2456 * thread. We need to see what we can do about knocking it 2457 * out of any sleep it may be in etc. 2458 */ 2459 static void 2460 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval) 2461 { 2462 struct proc *p = td->td_proc; 2463 int prop, wakeup_swapper; 2464 2465 PROC_LOCK_ASSERT(p, MA_OWNED); 2466 prop = sigprop(sig); 2467 2468 PROC_SLOCK(p); 2469 thread_lock(td); 2470 /* 2471 * Bring the priority of a thread up if we want it to get 2472 * killed in this lifetime. Be careful to avoid bumping the 2473 * priority of the idle thread, since we still allow to signal 2474 * kernel processes. 2475 */ 2476 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 && 2477 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2478 sched_prio(td, PUSER); 2479 if (TD_ON_SLEEPQ(td)) { 2480 /* 2481 * If thread is sleeping uninterruptibly 2482 * we can't interrupt the sleep... the signal will 2483 * be noticed when the process returns through 2484 * trap() or syscall(). 2485 */ 2486 if ((td->td_flags & TDF_SINTR) == 0) 2487 goto out; 2488 /* 2489 * If SIGCONT is default (or ignored) and process is 2490 * asleep, we are finished; the process should not 2491 * be awakened. 2492 */ 2493 if ((prop & SIGPROP_CONT) && action == SIG_DFL) { 2494 thread_unlock(td); 2495 PROC_SUNLOCK(p); 2496 sigqueue_delete(&p->p_sigqueue, sig); 2497 /* 2498 * It may be on either list in this state. 2499 * Remove from both for now. 2500 */ 2501 sigqueue_delete(&td->td_sigqueue, sig); 2502 return; 2503 } 2504 2505 /* 2506 * Don't awaken a sleeping thread for SIGSTOP if the 2507 * STOP signal is deferred. 2508 */ 2509 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY | 2510 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2511 goto out; 2512 2513 /* 2514 * Give low priority threads a better chance to run. 2515 */ 2516 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2517 sched_prio(td, PUSER); 2518 2519 wakeup_swapper = sig_sleepq_abort(td, intrval); 2520 PROC_SUNLOCK(p); 2521 if (wakeup_swapper) 2522 kick_proc0(); 2523 return; 2524 } 2525 2526 /* 2527 * Other states do nothing with the signal immediately, 2528 * other than kicking ourselves if we are running. 2529 * It will either never be noticed, or noticed very soon. 2530 */ 2531 #ifdef SMP 2532 if (TD_IS_RUNNING(td) && td != curthread) 2533 forward_signal(td); 2534 #endif 2535 2536 out: 2537 PROC_SUNLOCK(p); 2538 thread_unlock(td); 2539 } 2540 2541 static void 2542 ptrace_coredump(struct thread *td) 2543 { 2544 struct proc *p; 2545 struct thr_coredump_req *tcq; 2546 void *rl_cookie; 2547 2548 MPASS(td == curthread); 2549 p = td->td_proc; 2550 PROC_LOCK_ASSERT(p, MA_OWNED); 2551 if ((td->td_dbgflags & TDB_COREDUMPRQ) == 0) 2552 return; 2553 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped")); 2554 2555 tcq = td->td_coredump; 2556 KASSERT(tcq != NULL, ("td_coredump is NULL")); 2557 2558 if (p->p_sysent->sv_coredump == NULL) { 2559 tcq->tc_error = ENOSYS; 2560 goto wake; 2561 } 2562 2563 PROC_UNLOCK(p); 2564 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX); 2565 2566 tcq->tc_error = p->p_sysent->sv_coredump(td, tcq->tc_vp, 2567 tcq->tc_limit, tcq->tc_flags); 2568 2569 vn_rangelock_unlock(tcq->tc_vp, rl_cookie); 2570 PROC_LOCK(p); 2571 wake: 2572 td->td_dbgflags &= ~TDB_COREDUMPRQ; 2573 td->td_coredump = NULL; 2574 wakeup(p); 2575 } 2576 2577 static int 2578 sig_suspend_threads(struct thread *td, struct proc *p, int sending) 2579 { 2580 struct thread *td2; 2581 int wakeup_swapper; 2582 2583 PROC_LOCK_ASSERT(p, MA_OWNED); 2584 PROC_SLOCK_ASSERT(p, MA_OWNED); 2585 MPASS(sending || td == curthread); 2586 2587 wakeup_swapper = 0; 2588 FOREACH_THREAD_IN_PROC(p, td2) { 2589 thread_lock(td2); 2590 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK; 2591 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) && 2592 (td2->td_flags & TDF_SINTR)) { 2593 if (td2->td_flags & TDF_SBDRY) { 2594 /* 2595 * Once a thread is asleep with 2596 * TDF_SBDRY and without TDF_SERESTART 2597 * or TDF_SEINTR set, it should never 2598 * become suspended due to this check. 2599 */ 2600 KASSERT(!TD_IS_SUSPENDED(td2), 2601 ("thread with deferred stops suspended")); 2602 if (TD_SBDRY_INTR(td2)) { 2603 wakeup_swapper |= sleepq_abort(td2, 2604 TD_SBDRY_ERRNO(td2)); 2605 continue; 2606 } 2607 } else if (!TD_IS_SUSPENDED(td2)) 2608 thread_suspend_one(td2); 2609 } else if (!TD_IS_SUSPENDED(td2)) { 2610 if (sending || td != td2) 2611 td2->td_flags |= TDF_ASTPENDING; 2612 #ifdef SMP 2613 if (TD_IS_RUNNING(td2) && td2 != td) 2614 forward_signal(td2); 2615 #endif 2616 } 2617 thread_unlock(td2); 2618 } 2619 return (wakeup_swapper); 2620 } 2621 2622 /* 2623 * Stop the process for an event deemed interesting to the debugger. If si is 2624 * non-NULL, this is a signal exchange; the new signal requested by the 2625 * debugger will be returned for handling. If si is NULL, this is some other 2626 * type of interesting event. The debugger may request a signal be delivered in 2627 * that case as well, however it will be deferred until it can be handled. 2628 */ 2629 int 2630 ptracestop(struct thread *td, int sig, ksiginfo_t *si) 2631 { 2632 struct proc *p = td->td_proc; 2633 struct thread *td2; 2634 ksiginfo_t ksi; 2635 2636 PROC_LOCK_ASSERT(p, MA_OWNED); 2637 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); 2638 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2639 &p->p_mtx.lock_object, "Stopping for traced signal"); 2640 2641 td->td_xsig = sig; 2642 2643 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) { 2644 td->td_dbgflags |= TDB_XSIG; 2645 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d", 2646 td->td_tid, p->p_pid, td->td_dbgflags, sig); 2647 PROC_SLOCK(p); 2648 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) { 2649 if (P_KILLED(p)) { 2650 /* 2651 * Ensure that, if we've been PT_KILLed, the 2652 * exit status reflects that. Another thread 2653 * may also be in ptracestop(), having just 2654 * received the SIGKILL, but this thread was 2655 * unsuspended first. 2656 */ 2657 td->td_dbgflags &= ~TDB_XSIG; 2658 td->td_xsig = SIGKILL; 2659 p->p_ptevents = 0; 2660 break; 2661 } 2662 if (p->p_flag & P_SINGLE_EXIT && 2663 !(td->td_dbgflags & TDB_EXIT)) { 2664 /* 2665 * Ignore ptrace stops except for thread exit 2666 * events when the process exits. 2667 */ 2668 td->td_dbgflags &= ~TDB_XSIG; 2669 PROC_SUNLOCK(p); 2670 return (0); 2671 } 2672 2673 /* 2674 * Make wait(2) work. Ensure that right after the 2675 * attach, the thread which was decided to become the 2676 * leader of attach gets reported to the waiter. 2677 * Otherwise, just avoid overwriting another thread's 2678 * assignment to p_xthread. If another thread has 2679 * already set p_xthread, the current thread will get 2680 * a chance to report itself upon the next iteration. 2681 */ 2682 if ((td->td_dbgflags & TDB_FSTP) != 0 || 2683 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 && 2684 p->p_xthread == NULL)) { 2685 p->p_xsig = sig; 2686 p->p_xthread = td; 2687 2688 /* 2689 * If we are on sleepqueue already, 2690 * let sleepqueue code decide if it 2691 * needs to go sleep after attach. 2692 */ 2693 if (td->td_wchan == NULL) 2694 td->td_dbgflags &= ~TDB_FSTP; 2695 2696 p->p_flag2 &= ~P2_PTRACE_FSTP; 2697 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE; 2698 sig_suspend_threads(td, p, 0); 2699 } 2700 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) { 2701 td->td_dbgflags &= ~TDB_STOPATFORK; 2702 } 2703 stopme: 2704 td->td_dbgflags |= TDB_SSWITCH; 2705 thread_suspend_switch(td, p); 2706 td->td_dbgflags &= ~TDB_SSWITCH; 2707 if ((td->td_dbgflags & TDB_COREDUMPRQ) != 0) { 2708 PROC_SUNLOCK(p); 2709 ptrace_coredump(td); 2710 PROC_SLOCK(p); 2711 goto stopme; 2712 } 2713 if (p->p_xthread == td) 2714 p->p_xthread = NULL; 2715 if (!(p->p_flag & P_TRACED)) 2716 break; 2717 if (td->td_dbgflags & TDB_SUSPEND) { 2718 if (p->p_flag & P_SINGLE_EXIT) 2719 break; 2720 goto stopme; 2721 } 2722 } 2723 PROC_SUNLOCK(p); 2724 } 2725 2726 if (si != NULL && sig == td->td_xsig) { 2727 /* Parent wants us to take the original signal unchanged. */ 2728 si->ksi_flags |= KSI_HEAD; 2729 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0) 2730 si->ksi_signo = 0; 2731 } else if (td->td_xsig != 0) { 2732 /* 2733 * If parent wants us to take a new signal, then it will leave 2734 * it in td->td_xsig; otherwise we just look for signals again. 2735 */ 2736 ksiginfo_init(&ksi); 2737 ksi.ksi_signo = td->td_xsig; 2738 ksi.ksi_flags |= KSI_PTRACE; 2739 td2 = sigtd(p, td->td_xsig, false); 2740 tdsendsignal(p, td2, td->td_xsig, &ksi); 2741 if (td != td2) 2742 return (0); 2743 } 2744 2745 return (td->td_xsig); 2746 } 2747 2748 static void 2749 reschedule_signals(struct proc *p, sigset_t block, int flags) 2750 { 2751 struct sigacts *ps; 2752 struct thread *td; 2753 int sig; 2754 bool fastblk, pslocked; 2755 2756 PROC_LOCK_ASSERT(p, MA_OWNED); 2757 ps = p->p_sigacts; 2758 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0; 2759 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED); 2760 if (SIGISEMPTY(p->p_siglist)) 2761 return; 2762 SIGSETAND(block, p->p_siglist); 2763 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0; 2764 while ((sig = sig_ffs(&block)) != 0) { 2765 SIGDELSET(block, sig); 2766 td = sigtd(p, sig, fastblk); 2767 2768 /* 2769 * If sigtd() selected us despite sigfastblock is 2770 * blocking, do not activate AST or wake us, to avoid 2771 * loop in AST handler. 2772 */ 2773 if (fastblk && td == curthread) 2774 continue; 2775 2776 signotify(td); 2777 if (!pslocked) 2778 mtx_lock(&ps->ps_mtx); 2779 if (p->p_flag & P_TRACED || 2780 (SIGISMEMBER(ps->ps_sigcatch, sig) && 2781 !SIGISMEMBER(td->td_sigmask, sig))) { 2782 tdsigwakeup(td, sig, SIG_CATCH, 2783 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : 2784 ERESTART)); 2785 } 2786 if (!pslocked) 2787 mtx_unlock(&ps->ps_mtx); 2788 } 2789 } 2790 2791 void 2792 tdsigcleanup(struct thread *td) 2793 { 2794 struct proc *p; 2795 sigset_t unblocked; 2796 2797 p = td->td_proc; 2798 PROC_LOCK_ASSERT(p, MA_OWNED); 2799 2800 sigqueue_flush(&td->td_sigqueue); 2801 if (p->p_numthreads == 1) 2802 return; 2803 2804 /* 2805 * Since we cannot handle signals, notify signal post code 2806 * about this by filling the sigmask. 2807 * 2808 * Also, if needed, wake up thread(s) that do not block the 2809 * same signals as the exiting thread, since the thread might 2810 * have been selected for delivery and woken up. 2811 */ 2812 SIGFILLSET(unblocked); 2813 SIGSETNAND(unblocked, td->td_sigmask); 2814 SIGFILLSET(td->td_sigmask); 2815 reschedule_signals(p, unblocked, 0); 2816 2817 } 2818 2819 static int 2820 sigdeferstop_curr_flags(int cflags) 2821 { 2822 2823 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 || 2824 (cflags & TDF_SBDRY) != 0); 2825 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)); 2826 } 2827 2828 /* 2829 * Defer the delivery of SIGSTOP for the current thread, according to 2830 * the requested mode. Returns previous flags, which must be restored 2831 * by sigallowstop(). 2832 * 2833 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and 2834 * cleared by the current thread, which allow the lock-less read-only 2835 * accesses below. 2836 */ 2837 int 2838 sigdeferstop_impl(int mode) 2839 { 2840 struct thread *td; 2841 int cflags, nflags; 2842 2843 td = curthread; 2844 cflags = sigdeferstop_curr_flags(td->td_flags); 2845 switch (mode) { 2846 case SIGDEFERSTOP_NOP: 2847 nflags = cflags; 2848 break; 2849 case SIGDEFERSTOP_OFF: 2850 nflags = 0; 2851 break; 2852 case SIGDEFERSTOP_SILENT: 2853 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART); 2854 break; 2855 case SIGDEFERSTOP_EINTR: 2856 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART; 2857 break; 2858 case SIGDEFERSTOP_ERESTART: 2859 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR; 2860 break; 2861 default: 2862 panic("sigdeferstop: invalid mode %x", mode); 2863 break; 2864 } 2865 if (cflags == nflags) 2866 return (SIGDEFERSTOP_VAL_NCHG); 2867 thread_lock(td); 2868 td->td_flags = (td->td_flags & ~cflags) | nflags; 2869 thread_unlock(td); 2870 return (cflags); 2871 } 2872 2873 /* 2874 * Restores the STOP handling mode, typically permitting the delivery 2875 * of SIGSTOP for the current thread. This does not immediately 2876 * suspend if a stop was posted. Instead, the thread will suspend 2877 * either via ast() or a subsequent interruptible sleep. 2878 */ 2879 void 2880 sigallowstop_impl(int prev) 2881 { 2882 struct thread *td; 2883 int cflags; 2884 2885 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop")); 2886 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0, 2887 ("sigallowstop: incorrect previous mode %x", prev)); 2888 td = curthread; 2889 cflags = sigdeferstop_curr_flags(td->td_flags); 2890 if (cflags != prev) { 2891 thread_lock(td); 2892 td->td_flags = (td->td_flags & ~cflags) | prev; 2893 thread_unlock(td); 2894 } 2895 } 2896 2897 /* 2898 * If the current process has received a signal (should be caught or cause 2899 * termination, should interrupt current syscall), return the signal number. 2900 * Stop signals with default action are processed immediately, then cleared; 2901 * they aren't returned. This is checked after each entry to the system for 2902 * a syscall or trap (though this can usually be done without calling issignal 2903 * by checking the pending signal masks in cursig.) The normal call 2904 * sequence is 2905 * 2906 * while (sig = cursig(curthread)) 2907 * postsig(sig); 2908 */ 2909 static int 2910 issignal(struct thread *td) 2911 { 2912 struct proc *p; 2913 struct sigacts *ps; 2914 struct sigqueue *queue; 2915 sigset_t sigpending; 2916 ksiginfo_t ksi; 2917 int prop, sig; 2918 2919 p = td->td_proc; 2920 ps = p->p_sigacts; 2921 mtx_assert(&ps->ps_mtx, MA_OWNED); 2922 PROC_LOCK_ASSERT(p, MA_OWNED); 2923 for (;;) { 2924 sigpending = td->td_sigqueue.sq_signals; 2925 SIGSETOR(sigpending, p->p_sigqueue.sq_signals); 2926 SIGSETNAND(sigpending, td->td_sigmask); 2927 2928 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags & 2929 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2930 SIG_STOPSIGMASK(sigpending); 2931 if (SIGISEMPTY(sigpending)) /* no signal to send */ 2932 return (0); 2933 2934 /* 2935 * Do fast sigblock if requested by usermode. Since 2936 * we do know that there was a signal pending at this 2937 * point, set the FAST_SIGBLOCK_PEND as indicator for 2938 * usermode to perform a dummy call to 2939 * FAST_SIGBLOCK_UNBLOCK, which causes immediate 2940 * delivery of postponed pending signal. 2941 */ 2942 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 2943 if (td->td_sigblock_val != 0) 2944 SIGSETNAND(sigpending, fastblock_mask); 2945 if (SIGISEMPTY(sigpending)) { 2946 td->td_pflags |= TDP_SIGFASTPENDING; 2947 return (0); 2948 } 2949 } 2950 2951 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED && 2952 (p->p_flag2 & P2_PTRACE_FSTP) != 0 && 2953 SIGISMEMBER(sigpending, SIGSTOP)) { 2954 /* 2955 * If debugger just attached, always consume 2956 * SIGSTOP from ptrace(PT_ATTACH) first, to 2957 * execute the debugger attach ritual in 2958 * order. 2959 */ 2960 sig = SIGSTOP; 2961 td->td_dbgflags |= TDB_FSTP; 2962 } else { 2963 sig = sig_ffs(&sigpending); 2964 } 2965 2966 /* 2967 * We should allow pending but ignored signals below 2968 * only if there is sigwait() active, or P_TRACED was 2969 * on when they were posted. 2970 */ 2971 if (SIGISMEMBER(ps->ps_sigignore, sig) && 2972 (p->p_flag & P_TRACED) == 0 && 2973 (td->td_flags & TDF_SIGWAIT) == 0) { 2974 sigqueue_delete(&td->td_sigqueue, sig); 2975 sigqueue_delete(&p->p_sigqueue, sig); 2976 continue; 2977 } 2978 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) { 2979 /* 2980 * If traced, always stop. 2981 * Remove old signal from queue before the stop. 2982 * XXX shrug off debugger, it causes siginfo to 2983 * be thrown away. 2984 */ 2985 queue = &td->td_sigqueue; 2986 ksiginfo_init(&ksi); 2987 if (sigqueue_get(queue, sig, &ksi) == 0) { 2988 queue = &p->p_sigqueue; 2989 sigqueue_get(queue, sig, &ksi); 2990 } 2991 td->td_si = ksi.ksi_info; 2992 2993 mtx_unlock(&ps->ps_mtx); 2994 sig = ptracestop(td, sig, &ksi); 2995 mtx_lock(&ps->ps_mtx); 2996 2997 td->td_si.si_signo = 0; 2998 2999 /* 3000 * Keep looking if the debugger discarded or 3001 * replaced the signal. 3002 */ 3003 if (sig == 0) 3004 continue; 3005 3006 /* 3007 * If the signal became masked, re-queue it. 3008 */ 3009 if (SIGISMEMBER(td->td_sigmask, sig)) { 3010 ksi.ksi_flags |= KSI_HEAD; 3011 sigqueue_add(&p->p_sigqueue, sig, &ksi); 3012 continue; 3013 } 3014 3015 /* 3016 * If the traced bit got turned off, requeue 3017 * the signal and go back up to the top to 3018 * rescan signals. This ensures that p_sig* 3019 * and p_sigact are consistent. 3020 */ 3021 if ((p->p_flag & P_TRACED) == 0) { 3022 ksi.ksi_flags |= KSI_HEAD; 3023 sigqueue_add(queue, sig, &ksi); 3024 continue; 3025 } 3026 } 3027 3028 prop = sigprop(sig); 3029 3030 /* 3031 * Decide whether the signal should be returned. 3032 * Return the signal's number, or fall through 3033 * to clear it from the pending mask. 3034 */ 3035 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 3036 case (intptr_t)SIG_DFL: 3037 /* 3038 * Don't take default actions on system processes. 3039 */ 3040 if (p->p_pid <= 1) { 3041 #ifdef DIAGNOSTIC 3042 /* 3043 * Are you sure you want to ignore SIGSEGV 3044 * in init? XXX 3045 */ 3046 printf("Process (pid %lu) got signal %d\n", 3047 (u_long)p->p_pid, sig); 3048 #endif 3049 break; /* == ignore */ 3050 } 3051 /* 3052 * If there is a pending stop signal to process with 3053 * default action, stop here, then clear the signal. 3054 * Traced or exiting processes should ignore stops. 3055 * Additionally, a member of an orphaned process group 3056 * should ignore tty stops. 3057 */ 3058 if (prop & SIGPROP_STOP) { 3059 mtx_unlock(&ps->ps_mtx); 3060 if ((p->p_flag & (P_TRACED | P_WEXIT | 3061 P_SINGLE_EXIT)) != 0 || ((p->p_pgrp-> 3062 pg_flags & PGRP_ORPHANED) != 0 && 3063 (prop & SIGPROP_TTYSTOP) != 0)) { 3064 mtx_lock(&ps->ps_mtx); 3065 break; /* == ignore */ 3066 } 3067 if (TD_SBDRY_INTR(td)) { 3068 KASSERT((td->td_flags & TDF_SBDRY) != 0, 3069 ("lost TDF_SBDRY")); 3070 mtx_lock(&ps->ps_mtx); 3071 return (-1); 3072 } 3073 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 3074 &p->p_mtx.lock_object, "Catching SIGSTOP"); 3075 sigqueue_delete(&td->td_sigqueue, sig); 3076 sigqueue_delete(&p->p_sigqueue, sig); 3077 p->p_flag |= P_STOPPED_SIG; 3078 p->p_xsig = sig; 3079 PROC_SLOCK(p); 3080 sig_suspend_threads(td, p, 0); 3081 thread_suspend_switch(td, p); 3082 PROC_SUNLOCK(p); 3083 mtx_lock(&ps->ps_mtx); 3084 goto next; 3085 } else if ((prop & SIGPROP_IGNORE) != 0 && 3086 (td->td_flags & TDF_SIGWAIT) == 0) { 3087 /* 3088 * Default action is to ignore; drop it if 3089 * not in kern_sigtimedwait(). 3090 */ 3091 break; /* == ignore */ 3092 } else 3093 return (sig); 3094 /*NOTREACHED*/ 3095 3096 case (intptr_t)SIG_IGN: 3097 if ((td->td_flags & TDF_SIGWAIT) == 0) 3098 break; /* == ignore */ 3099 else 3100 return (sig); 3101 3102 default: 3103 /* 3104 * This signal has an action, let 3105 * postsig() process it. 3106 */ 3107 return (sig); 3108 } 3109 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */ 3110 sigqueue_delete(&p->p_sigqueue, sig); 3111 next:; 3112 } 3113 /* NOTREACHED */ 3114 } 3115 3116 void 3117 thread_stopped(struct proc *p) 3118 { 3119 int n; 3120 3121 PROC_LOCK_ASSERT(p, MA_OWNED); 3122 PROC_SLOCK_ASSERT(p, MA_OWNED); 3123 n = p->p_suspcount; 3124 if (p == curproc) 3125 n++; 3126 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) { 3127 PROC_SUNLOCK(p); 3128 p->p_flag &= ~P_WAITED; 3129 PROC_LOCK(p->p_pptr); 3130 childproc_stopped(p, (p->p_flag & P_TRACED) ? 3131 CLD_TRAPPED : CLD_STOPPED); 3132 PROC_UNLOCK(p->p_pptr); 3133 PROC_SLOCK(p); 3134 } 3135 } 3136 3137 /* 3138 * Take the action for the specified signal 3139 * from the current set of pending signals. 3140 */ 3141 int 3142 postsig(int sig) 3143 { 3144 struct thread *td; 3145 struct proc *p; 3146 struct sigacts *ps; 3147 sig_t action; 3148 ksiginfo_t ksi; 3149 sigset_t returnmask; 3150 3151 KASSERT(sig != 0, ("postsig")); 3152 3153 td = curthread; 3154 p = td->td_proc; 3155 PROC_LOCK_ASSERT(p, MA_OWNED); 3156 ps = p->p_sigacts; 3157 mtx_assert(&ps->ps_mtx, MA_OWNED); 3158 ksiginfo_init(&ksi); 3159 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 && 3160 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0) 3161 return (0); 3162 ksi.ksi_signo = sig; 3163 if (ksi.ksi_code == SI_TIMER) 3164 itimer_accept(p, ksi.ksi_timerid, &ksi); 3165 action = ps->ps_sigact[_SIG_IDX(sig)]; 3166 #ifdef KTRACE 3167 if (KTRPOINT(td, KTR_PSIG)) 3168 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ? 3169 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code); 3170 #endif 3171 3172 if (action == SIG_DFL) { 3173 /* 3174 * Default action, where the default is to kill 3175 * the process. (Other cases were ignored above.) 3176 */ 3177 mtx_unlock(&ps->ps_mtx); 3178 proc_td_siginfo_capture(td, &ksi.ksi_info); 3179 sigexit(td, sig); 3180 /* NOTREACHED */ 3181 } else { 3182 /* 3183 * If we get here, the signal must be caught. 3184 */ 3185 KASSERT(action != SIG_IGN, ("postsig action %p", action)); 3186 KASSERT(!SIGISMEMBER(td->td_sigmask, sig), 3187 ("postsig action: blocked sig %d", sig)); 3188 3189 /* 3190 * Set the new mask value and also defer further 3191 * occurrences of this signal. 3192 * 3193 * Special case: user has done a sigsuspend. Here the 3194 * current mask is not of interest, but rather the 3195 * mask from before the sigsuspend is what we want 3196 * restored after the signal processing is completed. 3197 */ 3198 if (td->td_pflags & TDP_OLDMASK) { 3199 returnmask = td->td_oldsigmask; 3200 td->td_pflags &= ~TDP_OLDMASK; 3201 } else 3202 returnmask = td->td_sigmask; 3203 3204 if (p->p_sig == sig) { 3205 p->p_sig = 0; 3206 } 3207 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask); 3208 postsig_done(sig, td, ps); 3209 } 3210 return (1); 3211 } 3212 3213 int 3214 sig_ast_checksusp(struct thread *td) 3215 { 3216 struct proc *p; 3217 int ret; 3218 3219 p = td->td_proc; 3220 PROC_LOCK_ASSERT(p, MA_OWNED); 3221 3222 if ((td->td_flags & TDF_NEEDSUSPCHK) == 0) 3223 return (0); 3224 3225 ret = thread_suspend_check(1); 3226 MPASS(ret == 0 || ret == EINTR || ret == ERESTART); 3227 return (ret); 3228 } 3229 3230 int 3231 sig_ast_needsigchk(struct thread *td) 3232 { 3233 struct proc *p; 3234 struct sigacts *ps; 3235 int ret, sig; 3236 3237 p = td->td_proc; 3238 PROC_LOCK_ASSERT(p, MA_OWNED); 3239 3240 if ((td->td_flags & TDF_NEEDSIGCHK) == 0) 3241 return (0); 3242 3243 ps = p->p_sigacts; 3244 mtx_lock(&ps->ps_mtx); 3245 sig = cursig(td); 3246 if (sig == -1) { 3247 mtx_unlock(&ps->ps_mtx); 3248 KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY")); 3249 KASSERT(TD_SBDRY_INTR(td), 3250 ("lost TDF_SERESTART of TDF_SEINTR")); 3251 KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) != 3252 (TDF_SEINTR | TDF_SERESTART), 3253 ("both TDF_SEINTR and TDF_SERESTART")); 3254 ret = TD_SBDRY_ERRNO(td); 3255 } else if (sig != 0) { 3256 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART; 3257 mtx_unlock(&ps->ps_mtx); 3258 } else { 3259 mtx_unlock(&ps->ps_mtx); 3260 ret = 0; 3261 } 3262 3263 /* 3264 * Do not go into sleep if this thread was the ptrace(2) 3265 * attach leader. cursig() consumed SIGSTOP from PT_ATTACH, 3266 * but we usually act on the signal by interrupting sleep, and 3267 * should do that here as well. 3268 */ 3269 if ((td->td_dbgflags & TDB_FSTP) != 0) { 3270 if (ret == 0) 3271 ret = EINTR; 3272 td->td_dbgflags &= ~TDB_FSTP; 3273 } 3274 3275 return (ret); 3276 } 3277 3278 int 3279 sig_intr(void) 3280 { 3281 struct thread *td; 3282 struct proc *p; 3283 int ret; 3284 3285 td = curthread; 3286 if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) == 0) 3287 return (0); 3288 3289 p = td->td_proc; 3290 3291 PROC_LOCK(p); 3292 ret = sig_ast_checksusp(td); 3293 if (ret == 0) 3294 ret = sig_ast_needsigchk(td); 3295 PROC_UNLOCK(p); 3296 return (ret); 3297 } 3298 3299 bool 3300 curproc_sigkilled(void) 3301 { 3302 struct thread *td; 3303 struct proc *p; 3304 struct sigacts *ps; 3305 bool res; 3306 3307 td = curthread; 3308 if ((td->td_flags & TDF_NEEDSIGCHK) == 0) 3309 return (false); 3310 3311 p = td->td_proc; 3312 PROC_LOCK(p); 3313 ps = p->p_sigacts; 3314 mtx_lock(&ps->ps_mtx); 3315 res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) || 3316 SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL); 3317 mtx_unlock(&ps->ps_mtx); 3318 PROC_UNLOCK(p); 3319 return (res); 3320 } 3321 3322 void 3323 proc_wkilled(struct proc *p) 3324 { 3325 3326 PROC_LOCK_ASSERT(p, MA_OWNED); 3327 if ((p->p_flag & P_WKILLED) == 0) { 3328 p->p_flag |= P_WKILLED; 3329 /* 3330 * Notify swapper that there is a process to swap in. 3331 * The notification is racy, at worst it would take 10 3332 * seconds for the swapper process to notice. 3333 */ 3334 if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0) 3335 wakeup(&proc0); 3336 } 3337 } 3338 3339 /* 3340 * Kill the current process for stated reason. 3341 */ 3342 void 3343 killproc(struct proc *p, const char *why) 3344 { 3345 3346 PROC_LOCK_ASSERT(p, MA_OWNED); 3347 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid, 3348 p->p_comm); 3349 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n", 3350 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id, 3351 p->p_ucred->cr_uid, why); 3352 proc_wkilled(p); 3353 kern_psignal(p, SIGKILL); 3354 } 3355 3356 /* 3357 * Force the current process to exit with the specified signal, dumping core 3358 * if appropriate. We bypass the normal tests for masked and caught signals, 3359 * allowing unrecoverable failures to terminate the process without changing 3360 * signal state. Mark the accounting record with the signal termination. 3361 * If dumping core, save the signal number for the debugger. Calls exit and 3362 * does not return. 3363 */ 3364 void 3365 sigexit(struct thread *td, int sig) 3366 { 3367 struct proc *p = td->td_proc; 3368 3369 PROC_LOCK_ASSERT(p, MA_OWNED); 3370 p->p_acflag |= AXSIG; 3371 /* 3372 * We must be single-threading to generate a core dump. This 3373 * ensures that the registers in the core file are up-to-date. 3374 * Also, the ELF dump handler assumes that the thread list doesn't 3375 * change out from under it. 3376 * 3377 * XXX If another thread attempts to single-thread before us 3378 * (e.g. via fork()), we won't get a dump at all. 3379 */ 3380 if ((sigprop(sig) & SIGPROP_CORE) && 3381 thread_single(p, SINGLE_NO_EXIT) == 0) { 3382 p->p_sig = sig; 3383 /* 3384 * Log signals which would cause core dumps 3385 * (Log as LOG_INFO to appease those who don't want 3386 * these messages.) 3387 * XXX : Todo, as well as euid, write out ruid too 3388 * Note that coredump() drops proc lock. 3389 */ 3390 if (coredump(td) == 0) 3391 sig |= WCOREFLAG; 3392 if (kern_logsigexit) 3393 log(LOG_INFO, 3394 "pid %d (%s), jid %d, uid %d: exited on " 3395 "signal %d%s\n", p->p_pid, p->p_comm, 3396 p->p_ucred->cr_prison->pr_id, 3397 td->td_ucred->cr_uid, 3398 sig &~ WCOREFLAG, 3399 sig & WCOREFLAG ? " (core dumped)" : ""); 3400 } else 3401 PROC_UNLOCK(p); 3402 exit1(td, 0, sig); 3403 /* NOTREACHED */ 3404 } 3405 3406 /* 3407 * Send queued SIGCHLD to parent when child process's state 3408 * is changed. 3409 */ 3410 static void 3411 sigparent(struct proc *p, int reason, int status) 3412 { 3413 PROC_LOCK_ASSERT(p, MA_OWNED); 3414 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3415 3416 if (p->p_ksi != NULL) { 3417 p->p_ksi->ksi_signo = SIGCHLD; 3418 p->p_ksi->ksi_code = reason; 3419 p->p_ksi->ksi_status = status; 3420 p->p_ksi->ksi_pid = p->p_pid; 3421 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid; 3422 if (KSI_ONQ(p->p_ksi)) 3423 return; 3424 } 3425 pksignal(p->p_pptr, SIGCHLD, p->p_ksi); 3426 } 3427 3428 static void 3429 childproc_jobstate(struct proc *p, int reason, int sig) 3430 { 3431 struct sigacts *ps; 3432 3433 PROC_LOCK_ASSERT(p, MA_OWNED); 3434 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3435 3436 /* 3437 * Wake up parent sleeping in kern_wait(), also send 3438 * SIGCHLD to parent, but SIGCHLD does not guarantee 3439 * that parent will awake, because parent may masked 3440 * the signal. 3441 */ 3442 p->p_pptr->p_flag |= P_STATCHILD; 3443 wakeup(p->p_pptr); 3444 3445 ps = p->p_pptr->p_sigacts; 3446 mtx_lock(&ps->ps_mtx); 3447 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) { 3448 mtx_unlock(&ps->ps_mtx); 3449 sigparent(p, reason, sig); 3450 } else 3451 mtx_unlock(&ps->ps_mtx); 3452 } 3453 3454 void 3455 childproc_stopped(struct proc *p, int reason) 3456 { 3457 3458 childproc_jobstate(p, reason, p->p_xsig); 3459 } 3460 3461 void 3462 childproc_continued(struct proc *p) 3463 { 3464 childproc_jobstate(p, CLD_CONTINUED, SIGCONT); 3465 } 3466 3467 void 3468 childproc_exited(struct proc *p) 3469 { 3470 int reason, status; 3471 3472 if (WCOREDUMP(p->p_xsig)) { 3473 reason = CLD_DUMPED; 3474 status = WTERMSIG(p->p_xsig); 3475 } else if (WIFSIGNALED(p->p_xsig)) { 3476 reason = CLD_KILLED; 3477 status = WTERMSIG(p->p_xsig); 3478 } else { 3479 reason = CLD_EXITED; 3480 status = p->p_xexit; 3481 } 3482 /* 3483 * XXX avoid calling wakeup(p->p_pptr), the work is 3484 * done in exit1(). 3485 */ 3486 sigparent(p, reason, status); 3487 } 3488 3489 #define MAX_NUM_CORE_FILES 100000 3490 #ifndef NUM_CORE_FILES 3491 #define NUM_CORE_FILES 5 3492 #endif 3493 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES); 3494 static int num_cores = NUM_CORE_FILES; 3495 3496 static int 3497 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS) 3498 { 3499 int error; 3500 int new_val; 3501 3502 new_val = num_cores; 3503 error = sysctl_handle_int(oidp, &new_val, 0, req); 3504 if (error != 0 || req->newptr == NULL) 3505 return (error); 3506 if (new_val > MAX_NUM_CORE_FILES) 3507 new_val = MAX_NUM_CORE_FILES; 3508 if (new_val < 0) 3509 new_val = 0; 3510 num_cores = new_val; 3511 return (0); 3512 } 3513 SYSCTL_PROC(_debug, OID_AUTO, ncores, 3514 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(int), 3515 sysctl_debug_num_cores_check, "I", 3516 "Maximum number of generated process corefiles while using index format"); 3517 3518 #define GZIP_SUFFIX ".gz" 3519 #define ZSTD_SUFFIX ".zst" 3520 3521 int compress_user_cores = 0; 3522 3523 static int 3524 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS) 3525 { 3526 int error, val; 3527 3528 val = compress_user_cores; 3529 error = sysctl_handle_int(oidp, &val, 0, req); 3530 if (error != 0 || req->newptr == NULL) 3531 return (error); 3532 if (val != 0 && !compressor_avail(val)) 3533 return (EINVAL); 3534 compress_user_cores = val; 3535 return (error); 3536 } 3537 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores, 3538 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int), 3539 sysctl_compress_user_cores, "I", 3540 "Enable compression of user corefiles (" 3541 __XSTRING(COMPRESS_GZIP) " = gzip, " 3542 __XSTRING(COMPRESS_ZSTD) " = zstd)"); 3543 3544 int compress_user_cores_level = 6; 3545 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN, 3546 &compress_user_cores_level, 0, 3547 "Corefile compression level"); 3548 3549 /* 3550 * Protect the access to corefilename[] by allproc_lock. 3551 */ 3552 #define corefilename_lock allproc_lock 3553 3554 static char corefilename[MAXPATHLEN] = {"%N.core"}; 3555 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename)); 3556 3557 static int 3558 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS) 3559 { 3560 int error; 3561 3562 sx_xlock(&corefilename_lock); 3563 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename), 3564 req); 3565 sx_xunlock(&corefilename_lock); 3566 3567 return (error); 3568 } 3569 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW | 3570 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", 3571 "Process corefile name format string"); 3572 3573 static void 3574 vnode_close_locked(struct thread *td, struct vnode *vp) 3575 { 3576 3577 VOP_UNLOCK(vp); 3578 vn_close(vp, FWRITE, td->td_ucred, td); 3579 } 3580 3581 /* 3582 * If the core format has a %I in it, then we need to check 3583 * for existing corefiles before defining a name. 3584 * To do this we iterate over 0..ncores to find a 3585 * non-existing core file name to use. If all core files are 3586 * already used we choose the oldest one. 3587 */ 3588 static int 3589 corefile_open_last(struct thread *td, char *name, int indexpos, 3590 int indexlen, int ncores, struct vnode **vpp) 3591 { 3592 struct vnode *oldvp, *nextvp, *vp; 3593 struct vattr vattr; 3594 struct nameidata nd; 3595 int error, i, flags, oflags, cmode; 3596 char ch; 3597 struct timespec lasttime; 3598 3599 nextvp = oldvp = NULL; 3600 cmode = S_IRUSR | S_IWUSR; 3601 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3602 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3603 3604 for (i = 0; i < ncores; i++) { 3605 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3606 3607 ch = name[indexpos + indexlen]; 3608 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen, 3609 i); 3610 name[indexpos + indexlen] = ch; 3611 3612 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3613 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 3614 NULL); 3615 if (error != 0) 3616 break; 3617 3618 vp = nd.ni_vp; 3619 NDFREE(&nd, NDF_ONLY_PNBUF); 3620 if ((flags & O_CREAT) == O_CREAT) { 3621 nextvp = vp; 3622 break; 3623 } 3624 3625 error = VOP_GETATTR(vp, &vattr, td->td_ucred); 3626 if (error != 0) { 3627 vnode_close_locked(td, vp); 3628 break; 3629 } 3630 3631 if (oldvp == NULL || 3632 lasttime.tv_sec > vattr.va_mtime.tv_sec || 3633 (lasttime.tv_sec == vattr.va_mtime.tv_sec && 3634 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) { 3635 if (oldvp != NULL) 3636 vn_close(oldvp, FWRITE, td->td_ucred, td); 3637 oldvp = vp; 3638 VOP_UNLOCK(oldvp); 3639 lasttime = vattr.va_mtime; 3640 } else { 3641 vnode_close_locked(td, vp); 3642 } 3643 } 3644 3645 if (oldvp != NULL) { 3646 if (nextvp == NULL) { 3647 if ((td->td_proc->p_flag & P_SUGID) != 0) { 3648 error = EFAULT; 3649 vn_close(oldvp, FWRITE, td->td_ucred, td); 3650 } else { 3651 nextvp = oldvp; 3652 error = vn_lock(nextvp, LK_EXCLUSIVE); 3653 if (error != 0) { 3654 vn_close(nextvp, FWRITE, td->td_ucred, 3655 td); 3656 nextvp = NULL; 3657 } 3658 } 3659 } else { 3660 vn_close(oldvp, FWRITE, td->td_ucred, td); 3661 } 3662 } 3663 if (error != 0) { 3664 if (nextvp != NULL) 3665 vnode_close_locked(td, oldvp); 3666 } else { 3667 *vpp = nextvp; 3668 } 3669 3670 return (error); 3671 } 3672 3673 /* 3674 * corefile_open(comm, uid, pid, td, compress, vpp, namep) 3675 * Expand the name described in corefilename, using name, uid, and pid 3676 * and open/create core file. 3677 * corefilename is a printf-like string, with three format specifiers: 3678 * %N name of process ("name") 3679 * %P process id (pid) 3680 * %U user id (uid) 3681 * For example, "%N.core" is the default; they can be disabled completely 3682 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 3683 * This is controlled by the sysctl variable kern.corefile (see above). 3684 */ 3685 static int 3686 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, 3687 int compress, int signum, struct vnode **vpp, char **namep) 3688 { 3689 struct sbuf sb; 3690 struct nameidata nd; 3691 const char *format; 3692 char *hostname, *name; 3693 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores; 3694 3695 hostname = NULL; 3696 format = corefilename; 3697 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO); 3698 indexlen = 0; 3699 indexpos = -1; 3700 ncores = num_cores; 3701 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN); 3702 sx_slock(&corefilename_lock); 3703 for (i = 0; format[i] != '\0'; i++) { 3704 switch (format[i]) { 3705 case '%': /* Format character */ 3706 i++; 3707 switch (format[i]) { 3708 case '%': 3709 sbuf_putc(&sb, '%'); 3710 break; 3711 case 'H': /* hostname */ 3712 if (hostname == NULL) { 3713 hostname = malloc(MAXHOSTNAMELEN, 3714 M_TEMP, M_WAITOK); 3715 } 3716 getcredhostname(td->td_ucred, hostname, 3717 MAXHOSTNAMELEN); 3718 sbuf_printf(&sb, "%s", hostname); 3719 break; 3720 case 'I': /* autoincrementing index */ 3721 if (indexpos != -1) { 3722 sbuf_printf(&sb, "%%I"); 3723 break; 3724 } 3725 3726 indexpos = sbuf_len(&sb); 3727 sbuf_printf(&sb, "%u", ncores - 1); 3728 indexlen = sbuf_len(&sb) - indexpos; 3729 break; 3730 case 'N': /* process name */ 3731 sbuf_printf(&sb, "%s", comm); 3732 break; 3733 case 'P': /* process id */ 3734 sbuf_printf(&sb, "%u", pid); 3735 break; 3736 case 'S': /* signal number */ 3737 sbuf_printf(&sb, "%i", signum); 3738 break; 3739 case 'U': /* user id */ 3740 sbuf_printf(&sb, "%u", uid); 3741 break; 3742 default: 3743 log(LOG_ERR, 3744 "Unknown format character %c in " 3745 "corename `%s'\n", format[i], format); 3746 break; 3747 } 3748 break; 3749 default: 3750 sbuf_putc(&sb, format[i]); 3751 break; 3752 } 3753 } 3754 sx_sunlock(&corefilename_lock); 3755 free(hostname, M_TEMP); 3756 if (compress == COMPRESS_GZIP) 3757 sbuf_printf(&sb, GZIP_SUFFIX); 3758 else if (compress == COMPRESS_ZSTD) 3759 sbuf_printf(&sb, ZSTD_SUFFIX); 3760 if (sbuf_error(&sb) != 0) { 3761 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too " 3762 "long\n", (long)pid, comm, (u_long)uid); 3763 sbuf_delete(&sb); 3764 free(name, M_TEMP); 3765 return (ENOMEM); 3766 } 3767 sbuf_finish(&sb); 3768 sbuf_delete(&sb); 3769 3770 if (indexpos != -1) { 3771 error = corefile_open_last(td, name, indexpos, indexlen, ncores, 3772 vpp); 3773 if (error != 0) { 3774 log(LOG_ERR, 3775 "pid %d (%s), uid (%u): Path `%s' failed " 3776 "on initial open test, error = %d\n", 3777 pid, comm, uid, name, error); 3778 } 3779 } else { 3780 cmode = S_IRUSR | S_IWUSR; 3781 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3782 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3783 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3784 if ((td->td_proc->p_flag & P_SUGID) != 0) 3785 flags |= O_EXCL; 3786 3787 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3788 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 3789 NULL); 3790 if (error == 0) { 3791 *vpp = nd.ni_vp; 3792 NDFREE(&nd, NDF_ONLY_PNBUF); 3793 } 3794 } 3795 3796 if (error != 0) { 3797 #ifdef AUDIT 3798 audit_proc_coredump(td, name, error); 3799 #endif 3800 free(name, M_TEMP); 3801 return (error); 3802 } 3803 *namep = name; 3804 return (0); 3805 } 3806 3807 /* 3808 * Dump a process' core. The main routine does some 3809 * policy checking, and creates the name of the coredump; 3810 * then it passes on a vnode and a size limit to the process-specific 3811 * coredump routine if there is one; if there _is not_ one, it returns 3812 * ENOSYS; otherwise it returns the error from the process-specific routine. 3813 */ 3814 3815 static int 3816 coredump(struct thread *td) 3817 { 3818 struct proc *p = td->td_proc; 3819 struct ucred *cred = td->td_ucred; 3820 struct vnode *vp; 3821 struct flock lf; 3822 struct vattr vattr; 3823 size_t fullpathsize; 3824 int error, error1, locked; 3825 char *name; /* name of corefile */ 3826 void *rl_cookie; 3827 off_t limit; 3828 char *fullpath, *freepath = NULL; 3829 struct sbuf *sb; 3830 3831 PROC_LOCK_ASSERT(p, MA_OWNED); 3832 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td); 3833 3834 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) || 3835 (p->p_flag2 & P2_NOTRACE) != 0) { 3836 PROC_UNLOCK(p); 3837 return (EFAULT); 3838 } 3839 3840 /* 3841 * Note that the bulk of limit checking is done after 3842 * the corefile is created. The exception is if the limit 3843 * for corefiles is 0, in which case we don't bother 3844 * creating the corefile at all. This layout means that 3845 * a corefile is truncated instead of not being created, 3846 * if it is larger than the limit. 3847 */ 3848 limit = (off_t)lim_cur(td, RLIMIT_CORE); 3849 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) { 3850 PROC_UNLOCK(p); 3851 return (EFBIG); 3852 } 3853 PROC_UNLOCK(p); 3854 3855 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, 3856 compress_user_cores, p->p_sig, &vp, &name); 3857 if (error != 0) 3858 return (error); 3859 3860 /* 3861 * Don't dump to non-regular files or files with links. 3862 * Do not dump into system files. Effective user must own the corefile. 3863 */ 3864 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 || 3865 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 || 3866 vattr.va_uid != cred->cr_uid) { 3867 VOP_UNLOCK(vp); 3868 error = EFAULT; 3869 goto out; 3870 } 3871 3872 VOP_UNLOCK(vp); 3873 3874 /* Postpone other writers, including core dumps of other processes. */ 3875 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 3876 3877 lf.l_whence = SEEK_SET; 3878 lf.l_start = 0; 3879 lf.l_len = 0; 3880 lf.l_type = F_WRLCK; 3881 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0); 3882 3883 VATTR_NULL(&vattr); 3884 vattr.va_size = 0; 3885 if (set_core_nodump_flag) 3886 vattr.va_flags = UF_NODUMP; 3887 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 3888 VOP_SETATTR(vp, &vattr, cred); 3889 VOP_UNLOCK(vp); 3890 PROC_LOCK(p); 3891 p->p_acflag |= ACORE; 3892 PROC_UNLOCK(p); 3893 3894 if (p->p_sysent->sv_coredump != NULL) { 3895 error = p->p_sysent->sv_coredump(td, vp, limit, 0); 3896 } else { 3897 error = ENOSYS; 3898 } 3899 3900 if (locked) { 3901 lf.l_type = F_UNLCK; 3902 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 3903 } 3904 vn_rangelock_unlock(vp, rl_cookie); 3905 3906 /* 3907 * Notify the userland helper that a process triggered a core dump. 3908 * This allows the helper to run an automated debugging session. 3909 */ 3910 if (error != 0 || coredump_devctl == 0) 3911 goto out; 3912 sb = sbuf_new_auto(); 3913 if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0) 3914 goto out2; 3915 sbuf_printf(sb, "comm=\""); 3916 devctl_safe_quote_sb(sb, fullpath); 3917 free(freepath, M_TEMP); 3918 sbuf_printf(sb, "\" core=\""); 3919 3920 /* 3921 * We can't lookup core file vp directly. When we're replacing a core, and 3922 * other random times, we flush the name cache, so it will fail. Instead, 3923 * if the path of the core is relative, add the current dir in front if it. 3924 */ 3925 if (name[0] != '/') { 3926 fullpathsize = MAXPATHLEN; 3927 freepath = malloc(fullpathsize, M_TEMP, M_WAITOK); 3928 if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) { 3929 free(freepath, M_TEMP); 3930 goto out2; 3931 } 3932 devctl_safe_quote_sb(sb, fullpath); 3933 free(freepath, M_TEMP); 3934 sbuf_putc(sb, '/'); 3935 } 3936 devctl_safe_quote_sb(sb, name); 3937 sbuf_printf(sb, "\""); 3938 if (sbuf_finish(sb) == 0) 3939 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb)); 3940 out2: 3941 sbuf_delete(sb); 3942 out: 3943 error1 = vn_close(vp, FWRITE, cred, td); 3944 if (error == 0) 3945 error = error1; 3946 #ifdef AUDIT 3947 audit_proc_coredump(td, name, error); 3948 #endif 3949 free(name, M_TEMP); 3950 return (error); 3951 } 3952 3953 /* 3954 * Nonexistent system call-- signal process (may want to handle it). Flag 3955 * error in case process won't see signal immediately (blocked or ignored). 3956 */ 3957 #ifndef _SYS_SYSPROTO_H_ 3958 struct nosys_args { 3959 int dummy; 3960 }; 3961 #endif 3962 /* ARGSUSED */ 3963 int 3964 nosys(struct thread *td, struct nosys_args *args) 3965 { 3966 struct proc *p; 3967 3968 p = td->td_proc; 3969 3970 PROC_LOCK(p); 3971 tdsignal(td, SIGSYS); 3972 PROC_UNLOCK(p); 3973 if (kern_lognosys == 1 || kern_lognosys == 3) { 3974 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 3975 td->td_sa.code); 3976 } 3977 if (kern_lognosys == 2 || kern_lognosys == 3 || 3978 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) { 3979 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 3980 td->td_sa.code); 3981 } 3982 return (ENOSYS); 3983 } 3984 3985 /* 3986 * Send a SIGIO or SIGURG signal to a process or process group using stored 3987 * credentials rather than those of the current process. 3988 */ 3989 void 3990 pgsigio(struct sigio **sigiop, int sig, int checkctty) 3991 { 3992 ksiginfo_t ksi; 3993 struct sigio *sigio; 3994 3995 ksiginfo_init(&ksi); 3996 ksi.ksi_signo = sig; 3997 ksi.ksi_code = SI_KERNEL; 3998 3999 SIGIO_LOCK(); 4000 sigio = *sigiop; 4001 if (sigio == NULL) { 4002 SIGIO_UNLOCK(); 4003 return; 4004 } 4005 if (sigio->sio_pgid > 0) { 4006 PROC_LOCK(sigio->sio_proc); 4007 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred)) 4008 kern_psignal(sigio->sio_proc, sig); 4009 PROC_UNLOCK(sigio->sio_proc); 4010 } else if (sigio->sio_pgid < 0) { 4011 struct proc *p; 4012 4013 PGRP_LOCK(sigio->sio_pgrp); 4014 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 4015 PROC_LOCK(p); 4016 if (p->p_state == PRS_NORMAL && 4017 CANSIGIO(sigio->sio_ucred, p->p_ucred) && 4018 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 4019 kern_psignal(p, sig); 4020 PROC_UNLOCK(p); 4021 } 4022 PGRP_UNLOCK(sigio->sio_pgrp); 4023 } 4024 SIGIO_UNLOCK(); 4025 } 4026 4027 static int 4028 filt_sigattach(struct knote *kn) 4029 { 4030 struct proc *p = curproc; 4031 4032 kn->kn_ptr.p_proc = p; 4033 kn->kn_flags |= EV_CLEAR; /* automatically set */ 4034 4035 knlist_add(p->p_klist, kn, 0); 4036 4037 return (0); 4038 } 4039 4040 static void 4041 filt_sigdetach(struct knote *kn) 4042 { 4043 struct proc *p = kn->kn_ptr.p_proc; 4044 4045 knlist_remove(p->p_klist, kn, 0); 4046 } 4047 4048 /* 4049 * signal knotes are shared with proc knotes, so we apply a mask to 4050 * the hint in order to differentiate them from process hints. This 4051 * could be avoided by using a signal-specific knote list, but probably 4052 * isn't worth the trouble. 4053 */ 4054 static int 4055 filt_signal(struct knote *kn, long hint) 4056 { 4057 4058 if (hint & NOTE_SIGNAL) { 4059 hint &= ~NOTE_SIGNAL; 4060 4061 if (kn->kn_id == hint) 4062 kn->kn_data++; 4063 } 4064 return (kn->kn_data != 0); 4065 } 4066 4067 struct sigacts * 4068 sigacts_alloc(void) 4069 { 4070 struct sigacts *ps; 4071 4072 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO); 4073 refcount_init(&ps->ps_refcnt, 1); 4074 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF); 4075 return (ps); 4076 } 4077 4078 void 4079 sigacts_free(struct sigacts *ps) 4080 { 4081 4082 if (refcount_release(&ps->ps_refcnt) == 0) 4083 return; 4084 mtx_destroy(&ps->ps_mtx); 4085 free(ps, M_SUBPROC); 4086 } 4087 4088 struct sigacts * 4089 sigacts_hold(struct sigacts *ps) 4090 { 4091 4092 refcount_acquire(&ps->ps_refcnt); 4093 return (ps); 4094 } 4095 4096 void 4097 sigacts_copy(struct sigacts *dest, struct sigacts *src) 4098 { 4099 4100 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest")); 4101 mtx_lock(&src->ps_mtx); 4102 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt)); 4103 mtx_unlock(&src->ps_mtx); 4104 } 4105 4106 int 4107 sigacts_shared(struct sigacts *ps) 4108 { 4109 4110 return (ps->ps_refcnt > 1); 4111 } 4112 4113 void 4114 sig_drop_caught(struct proc *p) 4115 { 4116 int sig; 4117 struct sigacts *ps; 4118 4119 ps = p->p_sigacts; 4120 PROC_LOCK_ASSERT(p, MA_OWNED); 4121 mtx_assert(&ps->ps_mtx, MA_OWNED); 4122 while (SIGNOTEMPTY(ps->ps_sigcatch)) { 4123 sig = sig_ffs(&ps->ps_sigcatch); 4124 sigdflt(ps, sig); 4125 if ((sigprop(sig) & SIGPROP_IGNORE) != 0) 4126 sigqueue_delete_proc(p, sig); 4127 } 4128 } 4129 4130 static void 4131 sigfastblock_failed(struct thread *td, bool sendsig, bool write) 4132 { 4133 ksiginfo_t ksi; 4134 4135 /* 4136 * Prevent further fetches and SIGSEGVs, allowing thread to 4137 * issue syscalls despite corruption. 4138 */ 4139 sigfastblock_clear(td); 4140 4141 if (!sendsig) 4142 return; 4143 ksiginfo_init_trap(&ksi); 4144 ksi.ksi_signo = SIGSEGV; 4145 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR; 4146 ksi.ksi_addr = td->td_sigblock_ptr; 4147 trapsignal(td, &ksi); 4148 } 4149 4150 static bool 4151 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp) 4152 { 4153 uint32_t res; 4154 4155 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4156 return (true); 4157 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) { 4158 sigfastblock_failed(td, sendsig, false); 4159 return (false); 4160 } 4161 *valp = res; 4162 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS; 4163 return (true); 4164 } 4165 4166 static void 4167 sigfastblock_resched(struct thread *td, bool resched) 4168 { 4169 struct proc *p; 4170 4171 if (resched) { 4172 p = td->td_proc; 4173 PROC_LOCK(p); 4174 reschedule_signals(p, td->td_sigmask, 0); 4175 PROC_UNLOCK(p); 4176 } 4177 thread_lock(td); 4178 td->td_flags |= TDF_ASTPENDING | TDF_NEEDSIGCHK; 4179 thread_unlock(td); 4180 } 4181 4182 int 4183 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap) 4184 { 4185 struct proc *p; 4186 int error, res; 4187 uint32_t oldval; 4188 4189 error = 0; 4190 p = td->td_proc; 4191 switch (uap->cmd) { 4192 case SIGFASTBLOCK_SETPTR: 4193 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 4194 error = EBUSY; 4195 break; 4196 } 4197 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) { 4198 error = EINVAL; 4199 break; 4200 } 4201 td->td_pflags |= TDP_SIGFASTBLOCK; 4202 td->td_sigblock_ptr = uap->ptr; 4203 break; 4204 4205 case SIGFASTBLOCK_UNBLOCK: 4206 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4207 error = EINVAL; 4208 break; 4209 } 4210 4211 for (;;) { 4212 res = casueword32(td->td_sigblock_ptr, 4213 SIGFASTBLOCK_PEND, &oldval, 0); 4214 if (res == -1) { 4215 error = EFAULT; 4216 sigfastblock_failed(td, false, true); 4217 break; 4218 } 4219 if (res == 0) 4220 break; 4221 MPASS(res == 1); 4222 if (oldval != SIGFASTBLOCK_PEND) { 4223 error = EBUSY; 4224 break; 4225 } 4226 error = thread_check_susp(td, false); 4227 if (error != 0) 4228 break; 4229 } 4230 if (error != 0) 4231 break; 4232 4233 /* 4234 * td_sigblock_val is cleared there, but not on a 4235 * syscall exit. The end effect is that a single 4236 * interruptible sleep, while user sigblock word is 4237 * set, might return EINTR or ERESTART to usermode 4238 * without delivering signal. All further sleeps, 4239 * until userspace clears the word and does 4240 * sigfastblock(UNBLOCK), observe current word and no 4241 * longer get interrupted. It is slight 4242 * non-conformance, with alternative to have read the 4243 * sigblock word on each syscall entry. 4244 */ 4245 td->td_sigblock_val = 0; 4246 4247 /* 4248 * Rely on normal ast mechanism to deliver pending 4249 * signals to current thread. But notify others about 4250 * fake unblock. 4251 */ 4252 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1); 4253 4254 break; 4255 4256 case SIGFASTBLOCK_UNSETPTR: 4257 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4258 error = EINVAL; 4259 break; 4260 } 4261 if (!sigfastblock_fetch_sig(td, false, &oldval)) { 4262 error = EFAULT; 4263 break; 4264 } 4265 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) { 4266 error = EBUSY; 4267 break; 4268 } 4269 sigfastblock_clear(td); 4270 break; 4271 4272 default: 4273 error = EINVAL; 4274 break; 4275 } 4276 return (error); 4277 } 4278 4279 void 4280 sigfastblock_clear(struct thread *td) 4281 { 4282 bool resched; 4283 4284 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4285 return; 4286 td->td_sigblock_val = 0; 4287 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 || 4288 SIGPENDING(td); 4289 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING); 4290 sigfastblock_resched(td, resched); 4291 } 4292 4293 void 4294 sigfastblock_fetch(struct thread *td) 4295 { 4296 uint32_t val; 4297 4298 (void)sigfastblock_fetch_sig(td, true, &val); 4299 } 4300 4301 static void 4302 sigfastblock_setpend1(struct thread *td) 4303 { 4304 int res; 4305 uint32_t oldval; 4306 4307 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0) 4308 return; 4309 res = fueword32((void *)td->td_sigblock_ptr, &oldval); 4310 if (res == -1) { 4311 sigfastblock_failed(td, true, false); 4312 return; 4313 } 4314 for (;;) { 4315 res = casueword32(td->td_sigblock_ptr, oldval, &oldval, 4316 oldval | SIGFASTBLOCK_PEND); 4317 if (res == -1) { 4318 sigfastblock_failed(td, true, true); 4319 return; 4320 } 4321 if (res == 0) { 4322 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS; 4323 td->td_pflags &= ~TDP_SIGFASTPENDING; 4324 break; 4325 } 4326 MPASS(res == 1); 4327 if (thread_check_susp(td, false) != 0) 4328 break; 4329 } 4330 } 4331 4332 void 4333 sigfastblock_setpend(struct thread *td, bool resched) 4334 { 4335 struct proc *p; 4336 4337 sigfastblock_setpend1(td); 4338 if (resched) { 4339 p = td->td_proc; 4340 PROC_LOCK(p); 4341 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK); 4342 PROC_UNLOCK(p); 4343 } 4344 } 4345