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 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL); 167 168 /* 169 * Policy -- Can ucred cr1 send SIGIO to process cr2? 170 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG 171 * in the right situations. 172 */ 173 #define CANSIGIO(cr1, cr2) \ 174 ((cr1)->cr_uid == 0 || \ 175 (cr1)->cr_ruid == (cr2)->cr_ruid || \ 176 (cr1)->cr_uid == (cr2)->cr_ruid || \ 177 (cr1)->cr_ruid == (cr2)->cr_uid || \ 178 (cr1)->cr_uid == (cr2)->cr_uid) 179 180 static int sugid_coredump; 181 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN, 182 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core"); 183 184 static int capmode_coredump; 185 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN, 186 &capmode_coredump, 0, "Allow processes in capability mode to dump core"); 187 188 static int do_coredump = 1; 189 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 190 &do_coredump, 0, "Enable/Disable coredumps"); 191 192 static int set_core_nodump_flag = 0; 193 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag, 194 0, "Enable setting the NODUMP flag on coredump files"); 195 196 static int coredump_devctl = 0; 197 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl, 198 0, "Generate a devctl notification when processes coredump"); 199 200 /* 201 * Signal properties and actions. 202 * The array below categorizes the signals and their default actions 203 * according to the following properties: 204 */ 205 #define SIGPROP_KILL 0x01 /* terminates process by default */ 206 #define SIGPROP_CORE 0x02 /* ditto and coredumps */ 207 #define SIGPROP_STOP 0x04 /* suspend process */ 208 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */ 209 #define SIGPROP_IGNORE 0x10 /* ignore by default */ 210 #define SIGPROP_CONT 0x20 /* continue if suspended */ 211 #define SIGPROP_CANTMASK 0x40 /* non-maskable, catchable */ 212 213 static int sigproptbl[NSIG] = { 214 [SIGHUP] = SIGPROP_KILL, 215 [SIGINT] = SIGPROP_KILL, 216 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE, 217 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE, 218 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE, 219 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE, 220 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE, 221 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE, 222 [SIGKILL] = SIGPROP_KILL, 223 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE, 224 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE, 225 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE, 226 [SIGPIPE] = SIGPROP_KILL, 227 [SIGALRM] = SIGPROP_KILL, 228 [SIGTERM] = SIGPROP_KILL, 229 [SIGURG] = SIGPROP_IGNORE, 230 [SIGSTOP] = SIGPROP_STOP, 231 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP, 232 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT, 233 [SIGCHLD] = SIGPROP_IGNORE, 234 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP, 235 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP, 236 [SIGIO] = SIGPROP_IGNORE, 237 [SIGXCPU] = SIGPROP_KILL, 238 [SIGXFSZ] = SIGPROP_KILL, 239 [SIGVTALRM] = SIGPROP_KILL, 240 [SIGPROF] = SIGPROP_KILL, 241 [SIGWINCH] = SIGPROP_IGNORE, 242 [SIGINFO] = SIGPROP_IGNORE, 243 [SIGUSR1] = SIGPROP_KILL, 244 [SIGUSR2] = SIGPROP_KILL, 245 }; 246 247 sigset_t fastblock_mask; 248 249 static void 250 sigqueue_start(void) 251 { 252 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t), 253 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 254 uma_prealloc(ksiginfo_zone, preallocate_siginfo); 255 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS); 256 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1); 257 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc); 258 SIGFILLSET(fastblock_mask); 259 SIG_CANTMASK(fastblock_mask); 260 } 261 262 ksiginfo_t * 263 ksiginfo_alloc(int wait) 264 { 265 int flags; 266 267 flags = M_ZERO; 268 if (! wait) 269 flags |= M_NOWAIT; 270 if (ksiginfo_zone != NULL) 271 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags)); 272 return (NULL); 273 } 274 275 void 276 ksiginfo_free(ksiginfo_t *ksi) 277 { 278 uma_zfree(ksiginfo_zone, ksi); 279 } 280 281 static __inline int 282 ksiginfo_tryfree(ksiginfo_t *ksi) 283 { 284 if (!(ksi->ksi_flags & KSI_EXT)) { 285 uma_zfree(ksiginfo_zone, ksi); 286 return (1); 287 } 288 return (0); 289 } 290 291 void 292 sigqueue_init(sigqueue_t *list, struct proc *p) 293 { 294 SIGEMPTYSET(list->sq_signals); 295 SIGEMPTYSET(list->sq_kill); 296 SIGEMPTYSET(list->sq_ptrace); 297 TAILQ_INIT(&list->sq_list); 298 list->sq_proc = p; 299 list->sq_flags = SQ_INIT; 300 } 301 302 /* 303 * Get a signal's ksiginfo. 304 * Return: 305 * 0 - signal not found 306 * others - signal number 307 */ 308 static int 309 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si) 310 { 311 struct proc *p = sq->sq_proc; 312 struct ksiginfo *ksi, *next; 313 int count = 0; 314 315 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 316 317 if (!SIGISMEMBER(sq->sq_signals, signo)) 318 return (0); 319 320 if (SIGISMEMBER(sq->sq_ptrace, signo)) { 321 count++; 322 SIGDELSET(sq->sq_ptrace, signo); 323 si->ksi_flags |= KSI_PTRACE; 324 } 325 if (SIGISMEMBER(sq->sq_kill, signo)) { 326 count++; 327 if (count == 1) 328 SIGDELSET(sq->sq_kill, signo); 329 } 330 331 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 332 if (ksi->ksi_signo == signo) { 333 if (count == 0) { 334 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 335 ksi->ksi_sigq = NULL; 336 ksiginfo_copy(ksi, si); 337 if (ksiginfo_tryfree(ksi) && p != NULL) 338 p->p_pendingcnt--; 339 } 340 if (++count > 1) 341 break; 342 } 343 } 344 345 if (count <= 1) 346 SIGDELSET(sq->sq_signals, signo); 347 si->ksi_signo = signo; 348 return (signo); 349 } 350 351 void 352 sigqueue_take(ksiginfo_t *ksi) 353 { 354 struct ksiginfo *kp; 355 struct proc *p; 356 sigqueue_t *sq; 357 358 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL) 359 return; 360 361 p = sq->sq_proc; 362 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 363 ksi->ksi_sigq = NULL; 364 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL) 365 p->p_pendingcnt--; 366 367 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL; 368 kp = TAILQ_NEXT(kp, ksi_link)) { 369 if (kp->ksi_signo == ksi->ksi_signo) 370 break; 371 } 372 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) && 373 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo)) 374 SIGDELSET(sq->sq_signals, ksi->ksi_signo); 375 } 376 377 static int 378 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si) 379 { 380 struct proc *p = sq->sq_proc; 381 struct ksiginfo *ksi; 382 int ret = 0; 383 384 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 385 386 /* 387 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path 388 * for these signals. 389 */ 390 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) { 391 SIGADDSET(sq->sq_kill, signo); 392 goto out_set_bit; 393 } 394 395 /* directly insert the ksi, don't copy it */ 396 if (si->ksi_flags & KSI_INS) { 397 if (si->ksi_flags & KSI_HEAD) 398 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link); 399 else 400 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link); 401 si->ksi_sigq = sq; 402 goto out_set_bit; 403 } 404 405 if (__predict_false(ksiginfo_zone == NULL)) { 406 SIGADDSET(sq->sq_kill, signo); 407 goto out_set_bit; 408 } 409 410 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) { 411 signal_overflow++; 412 ret = EAGAIN; 413 } else if ((ksi = ksiginfo_alloc(0)) == NULL) { 414 signal_alloc_fail++; 415 ret = EAGAIN; 416 } else { 417 if (p != NULL) 418 p->p_pendingcnt++; 419 ksiginfo_copy(si, ksi); 420 ksi->ksi_signo = signo; 421 if (si->ksi_flags & KSI_HEAD) 422 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link); 423 else 424 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link); 425 ksi->ksi_sigq = sq; 426 } 427 428 if (ret != 0) { 429 if ((si->ksi_flags & KSI_PTRACE) != 0) { 430 SIGADDSET(sq->sq_ptrace, signo); 431 ret = 0; 432 goto out_set_bit; 433 } else if ((si->ksi_flags & KSI_TRAP) != 0 || 434 (si->ksi_flags & KSI_SIGQ) == 0) { 435 SIGADDSET(sq->sq_kill, signo); 436 ret = 0; 437 goto out_set_bit; 438 } 439 return (ret); 440 } 441 442 out_set_bit: 443 SIGADDSET(sq->sq_signals, signo); 444 return (ret); 445 } 446 447 void 448 sigqueue_flush(sigqueue_t *sq) 449 { 450 struct proc *p = sq->sq_proc; 451 ksiginfo_t *ksi; 452 453 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 454 455 if (p != NULL) 456 PROC_LOCK_ASSERT(p, MA_OWNED); 457 458 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) { 459 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 460 ksi->ksi_sigq = NULL; 461 if (ksiginfo_tryfree(ksi) && p != NULL) 462 p->p_pendingcnt--; 463 } 464 465 SIGEMPTYSET(sq->sq_signals); 466 SIGEMPTYSET(sq->sq_kill); 467 SIGEMPTYSET(sq->sq_ptrace); 468 } 469 470 static void 471 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set) 472 { 473 sigset_t tmp; 474 struct proc *p1, *p2; 475 ksiginfo_t *ksi, *next; 476 477 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited")); 478 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited")); 479 p1 = src->sq_proc; 480 p2 = dst->sq_proc; 481 /* Move siginfo to target list */ 482 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) { 483 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 484 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link); 485 if (p1 != NULL) 486 p1->p_pendingcnt--; 487 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link); 488 ksi->ksi_sigq = dst; 489 if (p2 != NULL) 490 p2->p_pendingcnt++; 491 } 492 } 493 494 /* Move pending bits to target list */ 495 tmp = src->sq_kill; 496 SIGSETAND(tmp, *set); 497 SIGSETOR(dst->sq_kill, tmp); 498 SIGSETNAND(src->sq_kill, tmp); 499 500 tmp = src->sq_ptrace; 501 SIGSETAND(tmp, *set); 502 SIGSETOR(dst->sq_ptrace, tmp); 503 SIGSETNAND(src->sq_ptrace, tmp); 504 505 tmp = src->sq_signals; 506 SIGSETAND(tmp, *set); 507 SIGSETOR(dst->sq_signals, tmp); 508 SIGSETNAND(src->sq_signals, tmp); 509 } 510 511 #if 0 512 static void 513 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo) 514 { 515 sigset_t set; 516 517 SIGEMPTYSET(set); 518 SIGADDSET(set, signo); 519 sigqueue_move_set(src, dst, &set); 520 } 521 #endif 522 523 static void 524 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set) 525 { 526 struct proc *p = sq->sq_proc; 527 ksiginfo_t *ksi, *next; 528 529 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited")); 530 531 /* Remove siginfo queue */ 532 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 533 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 534 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 535 ksi->ksi_sigq = NULL; 536 if (ksiginfo_tryfree(ksi) && p != NULL) 537 p->p_pendingcnt--; 538 } 539 } 540 SIGSETNAND(sq->sq_kill, *set); 541 SIGSETNAND(sq->sq_ptrace, *set); 542 SIGSETNAND(sq->sq_signals, *set); 543 } 544 545 void 546 sigqueue_delete(sigqueue_t *sq, int signo) 547 { 548 sigset_t set; 549 550 SIGEMPTYSET(set); 551 SIGADDSET(set, signo); 552 sigqueue_delete_set(sq, &set); 553 } 554 555 /* Remove a set of signals for a process */ 556 static void 557 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set) 558 { 559 sigqueue_t worklist; 560 struct thread *td0; 561 562 PROC_LOCK_ASSERT(p, MA_OWNED); 563 564 sigqueue_init(&worklist, NULL); 565 sigqueue_move_set(&p->p_sigqueue, &worklist, set); 566 567 FOREACH_THREAD_IN_PROC(p, td0) 568 sigqueue_move_set(&td0->td_sigqueue, &worklist, set); 569 570 sigqueue_flush(&worklist); 571 } 572 573 void 574 sigqueue_delete_proc(struct proc *p, int signo) 575 { 576 sigset_t set; 577 578 SIGEMPTYSET(set); 579 SIGADDSET(set, signo); 580 sigqueue_delete_set_proc(p, &set); 581 } 582 583 static void 584 sigqueue_delete_stopmask_proc(struct proc *p) 585 { 586 sigset_t set; 587 588 SIGEMPTYSET(set); 589 SIGADDSET(set, SIGSTOP); 590 SIGADDSET(set, SIGTSTP); 591 SIGADDSET(set, SIGTTIN); 592 SIGADDSET(set, SIGTTOU); 593 sigqueue_delete_set_proc(p, &set); 594 } 595 596 /* 597 * Determine signal that should be delivered to thread td, the current 598 * thread, 0 if none. If there is a pending stop signal with default 599 * action, the process stops in issignal(). 600 */ 601 int 602 cursig(struct thread *td) 603 { 604 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 605 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED); 606 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 607 return (SIGPENDING(td) ? issignal(td) : 0); 608 } 609 610 /* 611 * Arrange for ast() to handle unmasked pending signals on return to user 612 * mode. This must be called whenever a signal is added to td_sigqueue or 613 * unmasked in td_sigmask. 614 */ 615 void 616 signotify(struct thread *td) 617 { 618 619 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 620 621 if (SIGPENDING(td)) { 622 thread_lock(td); 623 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING; 624 thread_unlock(td); 625 } 626 } 627 628 /* 629 * Returns 1 (true) if altstack is configured for the thread, and the 630 * passed stack bottom address falls into the altstack range. Handles 631 * the 43 compat special case where the alt stack size is zero. 632 */ 633 int 634 sigonstack(size_t sp) 635 { 636 struct thread *td; 637 638 td = curthread; 639 if ((td->td_pflags & TDP_ALTSTACK) == 0) 640 return (0); 641 #if defined(COMPAT_43) 642 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0) 643 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0); 644 #endif 645 return (sp >= (size_t)td->td_sigstk.ss_sp && 646 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp); 647 } 648 649 static __inline int 650 sigprop(int sig) 651 { 652 653 if (sig > 0 && sig < nitems(sigproptbl)) 654 return (sigproptbl[sig]); 655 return (0); 656 } 657 658 int 659 sig_ffs(sigset_t *set) 660 { 661 int i; 662 663 for (i = 0; i < _SIG_WORDS; i++) 664 if (set->__bits[i]) 665 return (ffs(set->__bits[i]) + (i * 32)); 666 return (0); 667 } 668 669 static bool 670 sigact_flag_test(const struct sigaction *act, int flag) 671 { 672 673 /* 674 * SA_SIGINFO is reset when signal disposition is set to 675 * ignore or default. Other flags are kept according to user 676 * settings. 677 */ 678 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO || 679 ((__sighandler_t *)act->sa_sigaction != SIG_IGN && 680 (__sighandler_t *)act->sa_sigaction != SIG_DFL))); 681 } 682 683 /* 684 * kern_sigaction 685 * sigaction 686 * freebsd4_sigaction 687 * osigaction 688 */ 689 int 690 kern_sigaction(struct thread *td, int sig, const struct sigaction *act, 691 struct sigaction *oact, int flags) 692 { 693 struct sigacts *ps; 694 struct proc *p = td->td_proc; 695 696 if (!_SIG_VALID(sig)) 697 return (EINVAL); 698 if (act != NULL && act->sa_handler != SIG_DFL && 699 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK | 700 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | 701 SA_NOCLDWAIT | SA_SIGINFO)) != 0) 702 return (EINVAL); 703 704 PROC_LOCK(p); 705 ps = p->p_sigacts; 706 mtx_lock(&ps->ps_mtx); 707 if (oact) { 708 memset(oact, 0, sizeof(*oact)); 709 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 710 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 711 oact->sa_flags |= SA_ONSTACK; 712 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 713 oact->sa_flags |= SA_RESTART; 714 if (SIGISMEMBER(ps->ps_sigreset, sig)) 715 oact->sa_flags |= SA_RESETHAND; 716 if (SIGISMEMBER(ps->ps_signodefer, sig)) 717 oact->sa_flags |= SA_NODEFER; 718 if (SIGISMEMBER(ps->ps_siginfo, sig)) { 719 oact->sa_flags |= SA_SIGINFO; 720 oact->sa_sigaction = 721 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)]; 722 } else 723 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 724 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP) 725 oact->sa_flags |= SA_NOCLDSTOP; 726 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT) 727 oact->sa_flags |= SA_NOCLDWAIT; 728 } 729 if (act) { 730 if ((sig == SIGKILL || sig == SIGSTOP) && 731 act->sa_handler != SIG_DFL) { 732 mtx_unlock(&ps->ps_mtx); 733 PROC_UNLOCK(p); 734 return (EINVAL); 735 } 736 737 /* 738 * Change setting atomically. 739 */ 740 741 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 742 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 743 if (sigact_flag_test(act, SA_SIGINFO)) { 744 ps->ps_sigact[_SIG_IDX(sig)] = 745 (__sighandler_t *)act->sa_sigaction; 746 SIGADDSET(ps->ps_siginfo, sig); 747 } else { 748 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 749 SIGDELSET(ps->ps_siginfo, sig); 750 } 751 if (!sigact_flag_test(act, SA_RESTART)) 752 SIGADDSET(ps->ps_sigintr, sig); 753 else 754 SIGDELSET(ps->ps_sigintr, sig); 755 if (sigact_flag_test(act, SA_ONSTACK)) 756 SIGADDSET(ps->ps_sigonstack, sig); 757 else 758 SIGDELSET(ps->ps_sigonstack, sig); 759 if (sigact_flag_test(act, SA_RESETHAND)) 760 SIGADDSET(ps->ps_sigreset, sig); 761 else 762 SIGDELSET(ps->ps_sigreset, sig); 763 if (sigact_flag_test(act, SA_NODEFER)) 764 SIGADDSET(ps->ps_signodefer, sig); 765 else 766 SIGDELSET(ps->ps_signodefer, sig); 767 if (sig == SIGCHLD) { 768 if (act->sa_flags & SA_NOCLDSTOP) 769 ps->ps_flag |= PS_NOCLDSTOP; 770 else 771 ps->ps_flag &= ~PS_NOCLDSTOP; 772 if (act->sa_flags & SA_NOCLDWAIT) { 773 /* 774 * Paranoia: since SA_NOCLDWAIT is implemented 775 * by reparenting the dying child to PID 1 (and 776 * trust it to reap the zombie), PID 1 itself 777 * is forbidden to set SA_NOCLDWAIT. 778 */ 779 if (p->p_pid == 1) 780 ps->ps_flag &= ~PS_NOCLDWAIT; 781 else 782 ps->ps_flag |= PS_NOCLDWAIT; 783 } else 784 ps->ps_flag &= ~PS_NOCLDWAIT; 785 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 786 ps->ps_flag |= PS_CLDSIGIGN; 787 else 788 ps->ps_flag &= ~PS_CLDSIGIGN; 789 } 790 /* 791 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 792 * and for signals set to SIG_DFL where the default is to 793 * ignore. However, don't put SIGCONT in ps_sigignore, as we 794 * have to restart the process. 795 */ 796 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 797 (sigprop(sig) & SIGPROP_IGNORE && 798 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 799 /* never to be seen again */ 800 sigqueue_delete_proc(p, sig); 801 if (sig != SIGCONT) 802 /* easier in psignal */ 803 SIGADDSET(ps->ps_sigignore, sig); 804 SIGDELSET(ps->ps_sigcatch, sig); 805 } else { 806 SIGDELSET(ps->ps_sigignore, sig); 807 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 808 SIGDELSET(ps->ps_sigcatch, sig); 809 else 810 SIGADDSET(ps->ps_sigcatch, sig); 811 } 812 #ifdef COMPAT_FREEBSD4 813 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 814 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 815 (flags & KSA_FREEBSD4) == 0) 816 SIGDELSET(ps->ps_freebsd4, sig); 817 else 818 SIGADDSET(ps->ps_freebsd4, sig); 819 #endif 820 #ifdef COMPAT_43 821 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 822 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 823 (flags & KSA_OSIGSET) == 0) 824 SIGDELSET(ps->ps_osigset, sig); 825 else 826 SIGADDSET(ps->ps_osigset, sig); 827 #endif 828 } 829 mtx_unlock(&ps->ps_mtx); 830 PROC_UNLOCK(p); 831 return (0); 832 } 833 834 #ifndef _SYS_SYSPROTO_H_ 835 struct sigaction_args { 836 int sig; 837 struct sigaction *act; 838 struct sigaction *oact; 839 }; 840 #endif 841 int 842 sys_sigaction(struct thread *td, struct sigaction_args *uap) 843 { 844 struct sigaction act, oact; 845 struct sigaction *actp, *oactp; 846 int error; 847 848 actp = (uap->act != NULL) ? &act : NULL; 849 oactp = (uap->oact != NULL) ? &oact : NULL; 850 if (actp) { 851 error = copyin(uap->act, actp, sizeof(act)); 852 if (error) 853 return (error); 854 } 855 error = kern_sigaction(td, uap->sig, actp, oactp, 0); 856 if (oactp && !error) 857 error = copyout(oactp, uap->oact, sizeof(oact)); 858 return (error); 859 } 860 861 #ifdef COMPAT_FREEBSD4 862 #ifndef _SYS_SYSPROTO_H_ 863 struct freebsd4_sigaction_args { 864 int sig; 865 struct sigaction *act; 866 struct sigaction *oact; 867 }; 868 #endif 869 int 870 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap) 871 { 872 struct sigaction act, oact; 873 struct sigaction *actp, *oactp; 874 int error; 875 876 actp = (uap->act != NULL) ? &act : NULL; 877 oactp = (uap->oact != NULL) ? &oact : NULL; 878 if (actp) { 879 error = copyin(uap->act, actp, sizeof(act)); 880 if (error) 881 return (error); 882 } 883 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4); 884 if (oactp && !error) 885 error = copyout(oactp, uap->oact, sizeof(oact)); 886 return (error); 887 } 888 #endif /* COMAPT_FREEBSD4 */ 889 890 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 891 #ifndef _SYS_SYSPROTO_H_ 892 struct osigaction_args { 893 int signum; 894 struct osigaction *nsa; 895 struct osigaction *osa; 896 }; 897 #endif 898 int 899 osigaction(struct thread *td, struct osigaction_args *uap) 900 { 901 struct osigaction sa; 902 struct sigaction nsa, osa; 903 struct sigaction *nsap, *osap; 904 int error; 905 906 if (uap->signum <= 0 || uap->signum >= ONSIG) 907 return (EINVAL); 908 909 nsap = (uap->nsa != NULL) ? &nsa : NULL; 910 osap = (uap->osa != NULL) ? &osa : NULL; 911 912 if (nsap) { 913 error = copyin(uap->nsa, &sa, sizeof(sa)); 914 if (error) 915 return (error); 916 nsap->sa_handler = sa.sa_handler; 917 nsap->sa_flags = sa.sa_flags; 918 OSIG2SIG(sa.sa_mask, nsap->sa_mask); 919 } 920 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 921 if (osap && !error) { 922 sa.sa_handler = osap->sa_handler; 923 sa.sa_flags = osap->sa_flags; 924 SIG2OSIG(osap->sa_mask, sa.sa_mask); 925 error = copyout(&sa, uap->osa, sizeof(sa)); 926 } 927 return (error); 928 } 929 930 #if !defined(__i386__) 931 /* Avoid replicating the same stub everywhere */ 932 int 933 osigreturn(struct thread *td, struct osigreturn_args *uap) 934 { 935 936 return (nosys(td, (struct nosys_args *)uap)); 937 } 938 #endif 939 #endif /* COMPAT_43 */ 940 941 /* 942 * Initialize signal state for process 0; 943 * set to ignore signals that are ignored by default. 944 */ 945 void 946 siginit(struct proc *p) 947 { 948 int i; 949 struct sigacts *ps; 950 951 PROC_LOCK(p); 952 ps = p->p_sigacts; 953 mtx_lock(&ps->ps_mtx); 954 for (i = 1; i <= NSIG; i++) { 955 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) { 956 SIGADDSET(ps->ps_sigignore, i); 957 } 958 } 959 mtx_unlock(&ps->ps_mtx); 960 PROC_UNLOCK(p); 961 } 962 963 /* 964 * Reset specified signal to the default disposition. 965 */ 966 static void 967 sigdflt(struct sigacts *ps, int sig) 968 { 969 970 mtx_assert(&ps->ps_mtx, MA_OWNED); 971 SIGDELSET(ps->ps_sigcatch, sig); 972 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT) 973 SIGADDSET(ps->ps_sigignore, sig); 974 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 975 SIGDELSET(ps->ps_siginfo, sig); 976 } 977 978 /* 979 * Reset signals for an exec of the specified process. 980 */ 981 void 982 execsigs(struct proc *p) 983 { 984 sigset_t osigignore; 985 struct sigacts *ps; 986 int sig; 987 struct thread *td; 988 989 /* 990 * Reset caught signals. Held signals remain held 991 * through td_sigmask (unless they were caught, 992 * and are now ignored by default). 993 */ 994 PROC_LOCK_ASSERT(p, MA_OWNED); 995 ps = p->p_sigacts; 996 mtx_lock(&ps->ps_mtx); 997 sig_drop_caught(p); 998 999 /* 1000 * As CloudABI processes cannot modify signal handlers, fully 1001 * reset all signals to their default behavior. Do ignore 1002 * SIGPIPE, as it would otherwise be impossible to recover from 1003 * writes to broken pipes and sockets. 1004 */ 1005 if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) { 1006 osigignore = ps->ps_sigignore; 1007 while (SIGNOTEMPTY(osigignore)) { 1008 sig = sig_ffs(&osigignore); 1009 SIGDELSET(osigignore, sig); 1010 if (sig != SIGPIPE) 1011 sigdflt(ps, sig); 1012 } 1013 SIGADDSET(ps->ps_sigignore, SIGPIPE); 1014 } 1015 1016 /* 1017 * Reset stack state to the user stack. 1018 * Clear set of signals caught on the signal stack. 1019 */ 1020 td = curthread; 1021 MPASS(td->td_proc == p); 1022 td->td_sigstk.ss_flags = SS_DISABLE; 1023 td->td_sigstk.ss_size = 0; 1024 td->td_sigstk.ss_sp = 0; 1025 td->td_pflags &= ~TDP_ALTSTACK; 1026 /* 1027 * Reset no zombies if child dies flag as Solaris does. 1028 */ 1029 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 1030 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 1031 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 1032 mtx_unlock(&ps->ps_mtx); 1033 } 1034 1035 /* 1036 * kern_sigprocmask() 1037 * 1038 * Manipulate signal mask. 1039 */ 1040 int 1041 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset, 1042 int flags) 1043 { 1044 sigset_t new_block, oset1; 1045 struct proc *p; 1046 int error; 1047 1048 p = td->td_proc; 1049 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0) 1050 PROC_LOCK_ASSERT(p, MA_OWNED); 1051 else 1052 PROC_LOCK(p); 1053 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 1054 ? MA_OWNED : MA_NOTOWNED); 1055 if (oset != NULL) 1056 *oset = td->td_sigmask; 1057 1058 error = 0; 1059 if (set != NULL) { 1060 switch (how) { 1061 case SIG_BLOCK: 1062 SIG_CANTMASK(*set); 1063 oset1 = td->td_sigmask; 1064 SIGSETOR(td->td_sigmask, *set); 1065 new_block = td->td_sigmask; 1066 SIGSETNAND(new_block, oset1); 1067 break; 1068 case SIG_UNBLOCK: 1069 SIGSETNAND(td->td_sigmask, *set); 1070 signotify(td); 1071 goto out; 1072 case SIG_SETMASK: 1073 SIG_CANTMASK(*set); 1074 oset1 = td->td_sigmask; 1075 if (flags & SIGPROCMASK_OLD) 1076 SIGSETLO(td->td_sigmask, *set); 1077 else 1078 td->td_sigmask = *set; 1079 new_block = td->td_sigmask; 1080 SIGSETNAND(new_block, oset1); 1081 signotify(td); 1082 break; 1083 default: 1084 error = EINVAL; 1085 goto out; 1086 } 1087 1088 /* 1089 * The new_block set contains signals that were not previously 1090 * blocked, but are blocked now. 1091 * 1092 * In case we block any signal that was not previously blocked 1093 * for td, and process has the signal pending, try to schedule 1094 * signal delivery to some thread that does not block the 1095 * signal, possibly waking it up. 1096 */ 1097 if (p->p_numthreads != 1) 1098 reschedule_signals(p, new_block, flags); 1099 } 1100 1101 out: 1102 if (!(flags & SIGPROCMASK_PROC_LOCKED)) 1103 PROC_UNLOCK(p); 1104 return (error); 1105 } 1106 1107 #ifndef _SYS_SYSPROTO_H_ 1108 struct sigprocmask_args { 1109 int how; 1110 const sigset_t *set; 1111 sigset_t *oset; 1112 }; 1113 #endif 1114 int 1115 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap) 1116 { 1117 sigset_t set, oset; 1118 sigset_t *setp, *osetp; 1119 int error; 1120 1121 setp = (uap->set != NULL) ? &set : NULL; 1122 osetp = (uap->oset != NULL) ? &oset : NULL; 1123 if (setp) { 1124 error = copyin(uap->set, setp, sizeof(set)); 1125 if (error) 1126 return (error); 1127 } 1128 error = kern_sigprocmask(td, uap->how, setp, osetp, 0); 1129 if (osetp && !error) { 1130 error = copyout(osetp, uap->oset, sizeof(oset)); 1131 } 1132 return (error); 1133 } 1134 1135 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1136 #ifndef _SYS_SYSPROTO_H_ 1137 struct osigprocmask_args { 1138 int how; 1139 osigset_t mask; 1140 }; 1141 #endif 1142 int 1143 osigprocmask(struct thread *td, struct osigprocmask_args *uap) 1144 { 1145 sigset_t set, oset; 1146 int error; 1147 1148 OSIG2SIG(uap->mask, set); 1149 error = kern_sigprocmask(td, uap->how, &set, &oset, 1); 1150 SIG2OSIG(oset, td->td_retval[0]); 1151 return (error); 1152 } 1153 #endif /* COMPAT_43 */ 1154 1155 int 1156 sys_sigwait(struct thread *td, struct sigwait_args *uap) 1157 { 1158 ksiginfo_t ksi; 1159 sigset_t set; 1160 int error; 1161 1162 error = copyin(uap->set, &set, sizeof(set)); 1163 if (error) { 1164 td->td_retval[0] = error; 1165 return (0); 1166 } 1167 1168 error = kern_sigtimedwait(td, set, &ksi, NULL); 1169 if (error) { 1170 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT) 1171 error = ERESTART; 1172 if (error == ERESTART) 1173 return (error); 1174 td->td_retval[0] = error; 1175 return (0); 1176 } 1177 1178 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo)); 1179 td->td_retval[0] = error; 1180 return (0); 1181 } 1182 1183 int 1184 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap) 1185 { 1186 struct timespec ts; 1187 struct timespec *timeout; 1188 sigset_t set; 1189 ksiginfo_t ksi; 1190 int error; 1191 1192 if (uap->timeout) { 1193 error = copyin(uap->timeout, &ts, sizeof(ts)); 1194 if (error) 1195 return (error); 1196 1197 timeout = &ts; 1198 } else 1199 timeout = NULL; 1200 1201 error = copyin(uap->set, &set, sizeof(set)); 1202 if (error) 1203 return (error); 1204 1205 error = kern_sigtimedwait(td, set, &ksi, timeout); 1206 if (error) 1207 return (error); 1208 1209 if (uap->info) 1210 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1211 1212 if (error == 0) 1213 td->td_retval[0] = ksi.ksi_signo; 1214 return (error); 1215 } 1216 1217 int 1218 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap) 1219 { 1220 ksiginfo_t ksi; 1221 sigset_t set; 1222 int error; 1223 1224 error = copyin(uap->set, &set, sizeof(set)); 1225 if (error) 1226 return (error); 1227 1228 error = kern_sigtimedwait(td, set, &ksi, NULL); 1229 if (error) 1230 return (error); 1231 1232 if (uap->info) 1233 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1234 1235 if (error == 0) 1236 td->td_retval[0] = ksi.ksi_signo; 1237 return (error); 1238 } 1239 1240 static void 1241 proc_td_siginfo_capture(struct thread *td, siginfo_t *si) 1242 { 1243 struct thread *thr; 1244 1245 FOREACH_THREAD_IN_PROC(td->td_proc, thr) { 1246 if (thr == td) 1247 thr->td_si = *si; 1248 else 1249 thr->td_si.si_signo = 0; 1250 } 1251 } 1252 1253 int 1254 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi, 1255 struct timespec *timeout) 1256 { 1257 struct sigacts *ps; 1258 sigset_t saved_mask, new_block; 1259 struct proc *p; 1260 int error, sig, timo, timevalid = 0; 1261 struct timespec rts, ets, ts; 1262 struct timeval tv; 1263 bool traced; 1264 1265 p = td->td_proc; 1266 error = 0; 1267 ets.tv_sec = 0; 1268 ets.tv_nsec = 0; 1269 traced = false; 1270 1271 if (timeout != NULL) { 1272 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { 1273 timevalid = 1; 1274 getnanouptime(&rts); 1275 timespecadd(&rts, timeout, &ets); 1276 } 1277 } 1278 ksiginfo_init(ksi); 1279 /* Some signals can not be waited for. */ 1280 SIG_CANTMASK(waitset); 1281 ps = p->p_sigacts; 1282 PROC_LOCK(p); 1283 saved_mask = td->td_sigmask; 1284 SIGSETNAND(td->td_sigmask, waitset); 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(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo); 1328 1329 if (timeout != NULL) { 1330 if (error == ERESTART) { 1331 /* Timeout can not be restarted. */ 1332 error = EINTR; 1333 } else if (error == EAGAIN) { 1334 /* We will calculate timeout by ourself. */ 1335 error = 0; 1336 } 1337 } 1338 1339 /* 1340 * If PTRACE_SCE or PTRACE_SCX were set after 1341 * userspace entered the syscall, return spurious 1342 * EINTR after wait was done. Only do this as last 1343 * resort after rechecking for possible queued signals 1344 * and expired timeouts. 1345 */ 1346 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0) 1347 traced = true; 1348 } 1349 1350 new_block = saved_mask; 1351 SIGSETNAND(new_block, td->td_sigmask); 1352 td->td_sigmask = saved_mask; 1353 /* 1354 * Fewer signals can be delivered to us, reschedule signal 1355 * notification. 1356 */ 1357 if (p->p_numthreads != 1) 1358 reschedule_signals(p, new_block, 0); 1359 1360 if (error == 0) { 1361 SDT_PROBE2(proc, , , signal__clear, sig, ksi); 1362 1363 if (ksi->ksi_code == SI_TIMER) 1364 itimer_accept(p, ksi->ksi_timerid, ksi); 1365 1366 #ifdef KTRACE 1367 if (KTRPOINT(td, KTR_PSIG)) { 1368 sig_t action; 1369 1370 mtx_lock(&ps->ps_mtx); 1371 action = ps->ps_sigact[_SIG_IDX(sig)]; 1372 mtx_unlock(&ps->ps_mtx); 1373 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code); 1374 } 1375 #endif 1376 if (sig == SIGKILL) { 1377 proc_td_siginfo_capture(td, &ksi->ksi_info); 1378 sigexit(td, sig); 1379 } 1380 } 1381 PROC_UNLOCK(p); 1382 return (error); 1383 } 1384 1385 #ifndef _SYS_SYSPROTO_H_ 1386 struct sigpending_args { 1387 sigset_t *set; 1388 }; 1389 #endif 1390 int 1391 sys_sigpending(struct thread *td, struct sigpending_args *uap) 1392 { 1393 struct proc *p = td->td_proc; 1394 sigset_t pending; 1395 1396 PROC_LOCK(p); 1397 pending = p->p_sigqueue.sq_signals; 1398 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1399 PROC_UNLOCK(p); 1400 return (copyout(&pending, uap->set, sizeof(sigset_t))); 1401 } 1402 1403 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1404 #ifndef _SYS_SYSPROTO_H_ 1405 struct osigpending_args { 1406 int dummy; 1407 }; 1408 #endif 1409 int 1410 osigpending(struct thread *td, struct osigpending_args *uap) 1411 { 1412 struct proc *p = td->td_proc; 1413 sigset_t pending; 1414 1415 PROC_LOCK(p); 1416 pending = p->p_sigqueue.sq_signals; 1417 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1418 PROC_UNLOCK(p); 1419 SIG2OSIG(pending, td->td_retval[0]); 1420 return (0); 1421 } 1422 #endif /* COMPAT_43 */ 1423 1424 #if defined(COMPAT_43) 1425 /* 1426 * Generalized interface signal handler, 4.3-compatible. 1427 */ 1428 #ifndef _SYS_SYSPROTO_H_ 1429 struct osigvec_args { 1430 int signum; 1431 struct sigvec *nsv; 1432 struct sigvec *osv; 1433 }; 1434 #endif 1435 /* ARGSUSED */ 1436 int 1437 osigvec(struct thread *td, struct osigvec_args *uap) 1438 { 1439 struct sigvec vec; 1440 struct sigaction nsa, osa; 1441 struct sigaction *nsap, *osap; 1442 int error; 1443 1444 if (uap->signum <= 0 || uap->signum >= ONSIG) 1445 return (EINVAL); 1446 nsap = (uap->nsv != NULL) ? &nsa : NULL; 1447 osap = (uap->osv != NULL) ? &osa : NULL; 1448 if (nsap) { 1449 error = copyin(uap->nsv, &vec, sizeof(vec)); 1450 if (error) 1451 return (error); 1452 nsap->sa_handler = vec.sv_handler; 1453 OSIG2SIG(vec.sv_mask, nsap->sa_mask); 1454 nsap->sa_flags = vec.sv_flags; 1455 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ 1456 } 1457 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 1458 if (osap && !error) { 1459 vec.sv_handler = osap->sa_handler; 1460 SIG2OSIG(osap->sa_mask, vec.sv_mask); 1461 vec.sv_flags = osap->sa_flags; 1462 vec.sv_flags &= ~SA_NOCLDWAIT; 1463 vec.sv_flags ^= SA_RESTART; 1464 error = copyout(&vec, uap->osv, sizeof(vec)); 1465 } 1466 return (error); 1467 } 1468 1469 #ifndef _SYS_SYSPROTO_H_ 1470 struct osigblock_args { 1471 int mask; 1472 }; 1473 #endif 1474 int 1475 osigblock(struct thread *td, struct osigblock_args *uap) 1476 { 1477 sigset_t set, oset; 1478 1479 OSIG2SIG(uap->mask, set); 1480 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0); 1481 SIG2OSIG(oset, td->td_retval[0]); 1482 return (0); 1483 } 1484 1485 #ifndef _SYS_SYSPROTO_H_ 1486 struct osigsetmask_args { 1487 int mask; 1488 }; 1489 #endif 1490 int 1491 osigsetmask(struct thread *td, struct osigsetmask_args *uap) 1492 { 1493 sigset_t set, oset; 1494 1495 OSIG2SIG(uap->mask, set); 1496 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0); 1497 SIG2OSIG(oset, td->td_retval[0]); 1498 return (0); 1499 } 1500 #endif /* COMPAT_43 */ 1501 1502 /* 1503 * Suspend calling thread until signal, providing mask to be set in the 1504 * meantime. 1505 */ 1506 #ifndef _SYS_SYSPROTO_H_ 1507 struct sigsuspend_args { 1508 const sigset_t *sigmask; 1509 }; 1510 #endif 1511 /* ARGSUSED */ 1512 int 1513 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap) 1514 { 1515 sigset_t mask; 1516 int error; 1517 1518 error = copyin(uap->sigmask, &mask, sizeof(mask)); 1519 if (error) 1520 return (error); 1521 return (kern_sigsuspend(td, mask)); 1522 } 1523 1524 int 1525 kern_sigsuspend(struct thread *td, sigset_t mask) 1526 { 1527 struct proc *p = td->td_proc; 1528 int has_sig, sig; 1529 1530 /* 1531 * When returning from sigsuspend, we want 1532 * the old mask to be restored after the 1533 * signal handler has finished. Thus, we 1534 * save it here and mark the sigacts structure 1535 * to indicate this. 1536 */ 1537 PROC_LOCK(p); 1538 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask, 1539 SIGPROCMASK_PROC_LOCKED); 1540 td->td_pflags |= TDP_OLDMASK; 1541 1542 /* 1543 * Process signals now. Otherwise, we can get spurious wakeup 1544 * due to signal entered process queue, but delivered to other 1545 * thread. But sigsuspend should return only on signal 1546 * delivery. 1547 */ 1548 (p->p_sysent->sv_set_syscall_retval)(td, EINTR); 1549 for (has_sig = 0; !has_sig;) { 1550 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 1551 0) == 0) 1552 /* void */; 1553 thread_suspend_check(0); 1554 mtx_lock(&p->p_sigacts->ps_mtx); 1555 while ((sig = cursig(td)) != 0) { 1556 KASSERT(sig >= 0, ("sig %d", sig)); 1557 has_sig += postsig(sig); 1558 } 1559 mtx_unlock(&p->p_sigacts->ps_mtx); 1560 1561 /* 1562 * If PTRACE_SCE or PTRACE_SCX were set after 1563 * userspace entered the syscall, return spurious 1564 * EINTR. 1565 */ 1566 if ((p->p_ptevents & PTRACE_SYSCALL) != 0) 1567 has_sig += 1; 1568 } 1569 PROC_UNLOCK(p); 1570 td->td_errno = EINTR; 1571 td->td_pflags |= TDP_NERRNO; 1572 return (EJUSTRETURN); 1573 } 1574 1575 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1576 /* 1577 * Compatibility sigsuspend call for old binaries. Note nonstandard calling 1578 * convention: libc stub passes mask, not pointer, to save a copyin. 1579 */ 1580 #ifndef _SYS_SYSPROTO_H_ 1581 struct osigsuspend_args { 1582 osigset_t mask; 1583 }; 1584 #endif 1585 /* ARGSUSED */ 1586 int 1587 osigsuspend(struct thread *td, struct osigsuspend_args *uap) 1588 { 1589 sigset_t mask; 1590 1591 OSIG2SIG(uap->mask, mask); 1592 return (kern_sigsuspend(td, mask)); 1593 } 1594 #endif /* COMPAT_43 */ 1595 1596 #if defined(COMPAT_43) 1597 #ifndef _SYS_SYSPROTO_H_ 1598 struct osigstack_args { 1599 struct sigstack *nss; 1600 struct sigstack *oss; 1601 }; 1602 #endif 1603 /* ARGSUSED */ 1604 int 1605 osigstack(struct thread *td, struct osigstack_args *uap) 1606 { 1607 struct sigstack nss, oss; 1608 int error = 0; 1609 1610 if (uap->nss != NULL) { 1611 error = copyin(uap->nss, &nss, sizeof(nss)); 1612 if (error) 1613 return (error); 1614 } 1615 oss.ss_sp = td->td_sigstk.ss_sp; 1616 oss.ss_onstack = sigonstack(cpu_getstack(td)); 1617 if (uap->nss != NULL) { 1618 td->td_sigstk.ss_sp = nss.ss_sp; 1619 td->td_sigstk.ss_size = 0; 1620 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK; 1621 td->td_pflags |= TDP_ALTSTACK; 1622 } 1623 if (uap->oss != NULL) 1624 error = copyout(&oss, uap->oss, sizeof(oss)); 1625 1626 return (error); 1627 } 1628 #endif /* COMPAT_43 */ 1629 1630 #ifndef _SYS_SYSPROTO_H_ 1631 struct sigaltstack_args { 1632 stack_t *ss; 1633 stack_t *oss; 1634 }; 1635 #endif 1636 /* ARGSUSED */ 1637 int 1638 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap) 1639 { 1640 stack_t ss, oss; 1641 int error; 1642 1643 if (uap->ss != NULL) { 1644 error = copyin(uap->ss, &ss, sizeof(ss)); 1645 if (error) 1646 return (error); 1647 } 1648 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL, 1649 (uap->oss != NULL) ? &oss : NULL); 1650 if (error) 1651 return (error); 1652 if (uap->oss != NULL) 1653 error = copyout(&oss, uap->oss, sizeof(stack_t)); 1654 return (error); 1655 } 1656 1657 int 1658 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss) 1659 { 1660 struct proc *p = td->td_proc; 1661 int oonstack; 1662 1663 oonstack = sigonstack(cpu_getstack(td)); 1664 1665 if (oss != NULL) { 1666 *oss = td->td_sigstk; 1667 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK) 1668 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 1669 } 1670 1671 if (ss != NULL) { 1672 if (oonstack) 1673 return (EPERM); 1674 if ((ss->ss_flags & ~SS_DISABLE) != 0) 1675 return (EINVAL); 1676 if (!(ss->ss_flags & SS_DISABLE)) { 1677 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 1678 return (ENOMEM); 1679 1680 td->td_sigstk = *ss; 1681 td->td_pflags |= TDP_ALTSTACK; 1682 } else { 1683 td->td_pflags &= ~TDP_ALTSTACK; 1684 } 1685 } 1686 return (0); 1687 } 1688 1689 struct killpg1_ctx { 1690 struct thread *td; 1691 ksiginfo_t *ksi; 1692 int sig; 1693 bool sent; 1694 bool found; 1695 int ret; 1696 }; 1697 1698 static void 1699 killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg) 1700 { 1701 int err; 1702 1703 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 || 1704 (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW) 1705 return; 1706 PROC_LOCK(p); 1707 err = p_cansignal(arg->td, p, arg->sig); 1708 if (err == 0 && arg->sig != 0) 1709 pksignal(p, arg->sig, arg->ksi); 1710 PROC_UNLOCK(p); 1711 if (err != ESRCH) 1712 arg->found = true; 1713 if (err == 0) 1714 arg->sent = true; 1715 else if (arg->ret == 0 && err != ESRCH && err != EPERM) 1716 arg->ret = err; 1717 } 1718 1719 /* 1720 * Common code for kill process group/broadcast kill. 1721 * cp is calling process. 1722 */ 1723 static int 1724 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi) 1725 { 1726 struct proc *p; 1727 struct pgrp *pgrp; 1728 struct killpg1_ctx arg; 1729 1730 arg.td = td; 1731 arg.ksi = ksi; 1732 arg.sig = sig; 1733 arg.sent = false; 1734 arg.found = false; 1735 arg.ret = 0; 1736 if (all) { 1737 /* 1738 * broadcast 1739 */ 1740 sx_slock(&allproc_lock); 1741 FOREACH_PROC_IN_SYSTEM(p) { 1742 killpg1_sendsig(p, true, &arg); 1743 } 1744 sx_sunlock(&allproc_lock); 1745 } else { 1746 sx_slock(&proctree_lock); 1747 if (pgid == 0) { 1748 /* 1749 * zero pgid means send to my process group. 1750 */ 1751 pgrp = td->td_proc->p_pgrp; 1752 PGRP_LOCK(pgrp); 1753 } else { 1754 pgrp = pgfind(pgid); 1755 if (pgrp == NULL) { 1756 sx_sunlock(&proctree_lock); 1757 return (ESRCH); 1758 } 1759 } 1760 sx_sunlock(&proctree_lock); 1761 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1762 killpg1_sendsig(p, false, &arg); 1763 } 1764 PGRP_UNLOCK(pgrp); 1765 } 1766 MPASS(arg.ret != 0 || arg.found || !arg.sent); 1767 if (arg.ret == 0 && !arg.sent) 1768 arg.ret = arg.found ? EPERM : ESRCH; 1769 return (arg.ret); 1770 } 1771 1772 #ifndef _SYS_SYSPROTO_H_ 1773 struct kill_args { 1774 int pid; 1775 int signum; 1776 }; 1777 #endif 1778 /* ARGSUSED */ 1779 int 1780 sys_kill(struct thread *td, struct kill_args *uap) 1781 { 1782 1783 return (kern_kill(td, uap->pid, uap->signum)); 1784 } 1785 1786 int 1787 kern_kill(struct thread *td, pid_t pid, int signum) 1788 { 1789 ksiginfo_t ksi; 1790 struct proc *p; 1791 int error; 1792 1793 /* 1794 * A process in capability mode can send signals only to himself. 1795 * The main rationale behind this is that abort(3) is implemented as 1796 * kill(getpid(), SIGABRT). 1797 */ 1798 if (IN_CAPABILITY_MODE(td) && pid != td->td_proc->p_pid) 1799 return (ECAPMODE); 1800 1801 AUDIT_ARG_SIGNUM(signum); 1802 AUDIT_ARG_PID(pid); 1803 if ((u_int)signum > _SIG_MAXSIG) 1804 return (EINVAL); 1805 1806 ksiginfo_init(&ksi); 1807 ksi.ksi_signo = signum; 1808 ksi.ksi_code = SI_USER; 1809 ksi.ksi_pid = td->td_proc->p_pid; 1810 ksi.ksi_uid = td->td_ucred->cr_ruid; 1811 1812 if (pid > 0) { 1813 /* kill single process */ 1814 if ((p = pfind_any(pid)) == NULL) 1815 return (ESRCH); 1816 AUDIT_ARG_PROCESS(p); 1817 error = p_cansignal(td, p, signum); 1818 if (error == 0 && signum) 1819 pksignal(p, signum, &ksi); 1820 PROC_UNLOCK(p); 1821 return (error); 1822 } 1823 switch (pid) { 1824 case -1: /* broadcast signal */ 1825 return (killpg1(td, signum, 0, 1, &ksi)); 1826 case 0: /* signal own process group */ 1827 return (killpg1(td, signum, 0, 0, &ksi)); 1828 default: /* negative explicit process group */ 1829 return (killpg1(td, signum, -pid, 0, &ksi)); 1830 } 1831 /* NOTREACHED */ 1832 } 1833 1834 int 1835 sys_pdkill(struct thread *td, struct pdkill_args *uap) 1836 { 1837 struct proc *p; 1838 int error; 1839 1840 AUDIT_ARG_SIGNUM(uap->signum); 1841 AUDIT_ARG_FD(uap->fd); 1842 if ((u_int)uap->signum > _SIG_MAXSIG) 1843 return (EINVAL); 1844 1845 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p); 1846 if (error) 1847 return (error); 1848 AUDIT_ARG_PROCESS(p); 1849 error = p_cansignal(td, p, uap->signum); 1850 if (error == 0 && uap->signum) 1851 kern_psignal(p, uap->signum); 1852 PROC_UNLOCK(p); 1853 return (error); 1854 } 1855 1856 #if defined(COMPAT_43) 1857 #ifndef _SYS_SYSPROTO_H_ 1858 struct okillpg_args { 1859 int pgid; 1860 int signum; 1861 }; 1862 #endif 1863 /* ARGSUSED */ 1864 int 1865 okillpg(struct thread *td, struct okillpg_args *uap) 1866 { 1867 ksiginfo_t ksi; 1868 1869 AUDIT_ARG_SIGNUM(uap->signum); 1870 AUDIT_ARG_PID(uap->pgid); 1871 if ((u_int)uap->signum > _SIG_MAXSIG) 1872 return (EINVAL); 1873 1874 ksiginfo_init(&ksi); 1875 ksi.ksi_signo = uap->signum; 1876 ksi.ksi_code = SI_USER; 1877 ksi.ksi_pid = td->td_proc->p_pid; 1878 ksi.ksi_uid = td->td_ucred->cr_ruid; 1879 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi)); 1880 } 1881 #endif /* COMPAT_43 */ 1882 1883 #ifndef _SYS_SYSPROTO_H_ 1884 struct sigqueue_args { 1885 pid_t pid; 1886 int signum; 1887 /* union sigval */ void *value; 1888 }; 1889 #endif 1890 int 1891 sys_sigqueue(struct thread *td, struct sigqueue_args *uap) 1892 { 1893 union sigval sv; 1894 1895 sv.sival_ptr = uap->value; 1896 1897 return (kern_sigqueue(td, uap->pid, uap->signum, &sv)); 1898 } 1899 1900 int 1901 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value) 1902 { 1903 ksiginfo_t ksi; 1904 struct proc *p; 1905 int error; 1906 1907 if ((u_int)signum > _SIG_MAXSIG) 1908 return (EINVAL); 1909 1910 /* 1911 * Specification says sigqueue can only send signal to 1912 * single process. 1913 */ 1914 if (pid <= 0) 1915 return (EINVAL); 1916 1917 if ((p = pfind_any(pid)) == NULL) 1918 return (ESRCH); 1919 error = p_cansignal(td, p, signum); 1920 if (error == 0 && signum != 0) { 1921 ksiginfo_init(&ksi); 1922 ksi.ksi_flags = KSI_SIGQ; 1923 ksi.ksi_signo = signum; 1924 ksi.ksi_code = SI_QUEUE; 1925 ksi.ksi_pid = td->td_proc->p_pid; 1926 ksi.ksi_uid = td->td_ucred->cr_ruid; 1927 ksi.ksi_value = *value; 1928 error = pksignal(p, ksi.ksi_signo, &ksi); 1929 } 1930 PROC_UNLOCK(p); 1931 return (error); 1932 } 1933 1934 /* 1935 * Send a signal to a process group. 1936 */ 1937 void 1938 gsignal(int pgid, int sig, ksiginfo_t *ksi) 1939 { 1940 struct pgrp *pgrp; 1941 1942 if (pgid != 0) { 1943 sx_slock(&proctree_lock); 1944 pgrp = pgfind(pgid); 1945 sx_sunlock(&proctree_lock); 1946 if (pgrp != NULL) { 1947 pgsignal(pgrp, sig, 0, ksi); 1948 PGRP_UNLOCK(pgrp); 1949 } 1950 } 1951 } 1952 1953 /* 1954 * Send a signal to a process group. If checktty is 1, 1955 * limit to members which have a controlling terminal. 1956 */ 1957 void 1958 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi) 1959 { 1960 struct proc *p; 1961 1962 if (pgrp) { 1963 PGRP_LOCK_ASSERT(pgrp, MA_OWNED); 1964 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1965 PROC_LOCK(p); 1966 if (p->p_state == PRS_NORMAL && 1967 (checkctty == 0 || p->p_flag & P_CONTROLT)) 1968 pksignal(p, sig, ksi); 1969 PROC_UNLOCK(p); 1970 } 1971 } 1972 } 1973 1974 /* 1975 * Recalculate the signal mask and reset the signal disposition after 1976 * usermode frame for delivery is formed. Should be called after 1977 * mach-specific routine, because sysent->sv_sendsig() needs correct 1978 * ps_siginfo and signal mask. 1979 */ 1980 static void 1981 postsig_done(int sig, struct thread *td, struct sigacts *ps) 1982 { 1983 sigset_t mask; 1984 1985 mtx_assert(&ps->ps_mtx, MA_OWNED); 1986 td->td_ru.ru_nsignals++; 1987 mask = ps->ps_catchmask[_SIG_IDX(sig)]; 1988 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1989 SIGADDSET(mask, sig); 1990 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, 1991 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); 1992 if (SIGISMEMBER(ps->ps_sigreset, sig)) 1993 sigdflt(ps, sig); 1994 } 1995 1996 /* 1997 * Send a signal caused by a trap to the current thread. If it will be 1998 * caught immediately, deliver it with correct code. Otherwise, post it 1999 * normally. 2000 */ 2001 void 2002 trapsignal(struct thread *td, ksiginfo_t *ksi) 2003 { 2004 struct sigacts *ps; 2005 struct proc *p; 2006 sigset_t sigmask; 2007 int code, sig; 2008 2009 p = td->td_proc; 2010 sig = ksi->ksi_signo; 2011 code = ksi->ksi_code; 2012 KASSERT(_SIG_VALID(sig), ("invalid signal")); 2013 2014 sigfastblock_fetch(td); 2015 PROC_LOCK(p); 2016 ps = p->p_sigacts; 2017 mtx_lock(&ps->ps_mtx); 2018 sigmask = td->td_sigmask; 2019 if (td->td_sigblock_val != 0) 2020 SIGSETOR(sigmask, fastblock_mask); 2021 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) && 2022 !SIGISMEMBER(sigmask, sig)) { 2023 #ifdef KTRACE 2024 if (KTRPOINT(curthread, KTR_PSIG)) 2025 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)], 2026 &td->td_sigmask, code); 2027 #endif 2028 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], 2029 ksi, &td->td_sigmask); 2030 postsig_done(sig, td, ps); 2031 mtx_unlock(&ps->ps_mtx); 2032 } else { 2033 /* 2034 * Avoid a possible infinite loop if the thread 2035 * masking the signal or process is ignoring the 2036 * signal. 2037 */ 2038 if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) || 2039 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) { 2040 SIGDELSET(td->td_sigmask, sig); 2041 SIGDELSET(ps->ps_sigcatch, sig); 2042 SIGDELSET(ps->ps_sigignore, sig); 2043 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2044 td->td_pflags &= ~TDP_SIGFASTBLOCK; 2045 td->td_sigblock_val = 0; 2046 } 2047 mtx_unlock(&ps->ps_mtx); 2048 p->p_sig = sig; /* XXX to verify code */ 2049 tdsendsignal(p, td, sig, ksi); 2050 } 2051 PROC_UNLOCK(p); 2052 } 2053 2054 static struct thread * 2055 sigtd(struct proc *p, int sig, bool fast_sigblock) 2056 { 2057 struct thread *td, *signal_td; 2058 2059 PROC_LOCK_ASSERT(p, MA_OWNED); 2060 MPASS(!fast_sigblock || p == curproc); 2061 2062 /* 2063 * Check if current thread can handle the signal without 2064 * switching context to another thread. 2065 */ 2066 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) && 2067 (!fast_sigblock || curthread->td_sigblock_val == 0)) 2068 return (curthread); 2069 signal_td = NULL; 2070 FOREACH_THREAD_IN_PROC(p, td) { 2071 if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock || 2072 td != curthread || td->td_sigblock_val == 0)) { 2073 signal_td = td; 2074 break; 2075 } 2076 } 2077 if (signal_td == NULL) 2078 signal_td = FIRST_THREAD_IN_PROC(p); 2079 return (signal_td); 2080 } 2081 2082 /* 2083 * Send the signal to the process. If the signal has an action, the action 2084 * is usually performed by the target process rather than the caller; we add 2085 * the signal to the set of pending signals for the process. 2086 * 2087 * Exceptions: 2088 * o When a stop signal is sent to a sleeping process that takes the 2089 * default action, the process is stopped without awakening it. 2090 * o SIGCONT restarts stopped processes (or puts them back to sleep) 2091 * regardless of the signal action (eg, blocked or ignored). 2092 * 2093 * Other ignored signals are discarded immediately. 2094 * 2095 * NB: This function may be entered from the debugger via the "kill" DDB 2096 * command. There is little that can be done to mitigate the possibly messy 2097 * side effects of this unwise possibility. 2098 */ 2099 void 2100 kern_psignal(struct proc *p, int sig) 2101 { 2102 ksiginfo_t ksi; 2103 2104 ksiginfo_init(&ksi); 2105 ksi.ksi_signo = sig; 2106 ksi.ksi_code = SI_KERNEL; 2107 (void) tdsendsignal(p, NULL, sig, &ksi); 2108 } 2109 2110 int 2111 pksignal(struct proc *p, int sig, ksiginfo_t *ksi) 2112 { 2113 2114 return (tdsendsignal(p, NULL, sig, ksi)); 2115 } 2116 2117 /* Utility function for finding a thread to send signal event to. */ 2118 int 2119 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd) 2120 { 2121 struct thread *td; 2122 2123 if (sigev->sigev_notify == SIGEV_THREAD_ID) { 2124 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid); 2125 if (td == NULL) 2126 return (ESRCH); 2127 *ttd = td; 2128 } else { 2129 *ttd = NULL; 2130 PROC_LOCK(p); 2131 } 2132 return (0); 2133 } 2134 2135 void 2136 tdsignal(struct thread *td, int sig) 2137 { 2138 ksiginfo_t ksi; 2139 2140 ksiginfo_init(&ksi); 2141 ksi.ksi_signo = sig; 2142 ksi.ksi_code = SI_KERNEL; 2143 (void) tdsendsignal(td->td_proc, td, sig, &ksi); 2144 } 2145 2146 void 2147 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi) 2148 { 2149 2150 (void) tdsendsignal(td->td_proc, td, sig, ksi); 2151 } 2152 2153 int 2154 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) 2155 { 2156 sig_t action; 2157 sigqueue_t *sigqueue; 2158 int prop; 2159 struct sigacts *ps; 2160 int intrval; 2161 int ret = 0; 2162 int wakeup_swapper; 2163 2164 MPASS(td == NULL || p == td->td_proc); 2165 PROC_LOCK_ASSERT(p, MA_OWNED); 2166 2167 if (!_SIG_VALID(sig)) 2168 panic("%s(): invalid signal %d", __func__, sig); 2169 2170 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__)); 2171 2172 /* 2173 * IEEE Std 1003.1-2001: return success when killing a zombie. 2174 */ 2175 if (p->p_state == PRS_ZOMBIE) { 2176 if (ksi && (ksi->ksi_flags & KSI_INS)) 2177 ksiginfo_tryfree(ksi); 2178 return (ret); 2179 } 2180 2181 ps = p->p_sigacts; 2182 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig); 2183 prop = sigprop(sig); 2184 2185 if (td == NULL) { 2186 td = sigtd(p, sig, false); 2187 sigqueue = &p->p_sigqueue; 2188 } else 2189 sigqueue = &td->td_sigqueue; 2190 2191 SDT_PROBE3(proc, , , signal__send, td, p, sig); 2192 2193 /* 2194 * If the signal is being ignored, 2195 * then we forget about it immediately. 2196 * (Note: we don't set SIGCONT in ps_sigignore, 2197 * and if it is set to SIG_IGN, 2198 * action will be SIG_DFL here.) 2199 */ 2200 mtx_lock(&ps->ps_mtx); 2201 if (SIGISMEMBER(ps->ps_sigignore, sig)) { 2202 SDT_PROBE3(proc, , , signal__discard, td, p, sig); 2203 2204 mtx_unlock(&ps->ps_mtx); 2205 if (ksi && (ksi->ksi_flags & KSI_INS)) 2206 ksiginfo_tryfree(ksi); 2207 return (ret); 2208 } 2209 if (SIGISMEMBER(td->td_sigmask, sig)) 2210 action = SIG_HOLD; 2211 else if (SIGISMEMBER(ps->ps_sigcatch, sig)) 2212 action = SIG_CATCH; 2213 else 2214 action = SIG_DFL; 2215 if (SIGISMEMBER(ps->ps_sigintr, sig)) 2216 intrval = EINTR; 2217 else 2218 intrval = ERESTART; 2219 mtx_unlock(&ps->ps_mtx); 2220 2221 if (prop & SIGPROP_CONT) 2222 sigqueue_delete_stopmask_proc(p); 2223 else if (prop & SIGPROP_STOP) { 2224 /* 2225 * If sending a tty stop signal to a member of an orphaned 2226 * process group, discard the signal here if the action 2227 * is default; don't stop the process below if sleeping, 2228 * and don't clear any pending SIGCONT. 2229 */ 2230 if ((prop & SIGPROP_TTYSTOP) && 2231 (p->p_pgrp->pg_jobc == 0) && 2232 (action == SIG_DFL)) { 2233 if (ksi && (ksi->ksi_flags & KSI_INS)) 2234 ksiginfo_tryfree(ksi); 2235 return (ret); 2236 } 2237 sigqueue_delete_proc(p, SIGCONT); 2238 if (p->p_flag & P_CONTINUED) { 2239 p->p_flag &= ~P_CONTINUED; 2240 PROC_LOCK(p->p_pptr); 2241 sigqueue_take(p->p_ksi); 2242 PROC_UNLOCK(p->p_pptr); 2243 } 2244 } 2245 2246 ret = sigqueue_add(sigqueue, sig, ksi); 2247 if (ret != 0) 2248 return (ret); 2249 signotify(td); 2250 /* 2251 * Defer further processing for signals which are held, 2252 * except that stopped processes must be continued by SIGCONT. 2253 */ 2254 if (action == SIG_HOLD && 2255 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG))) 2256 return (ret); 2257 2258 wakeup_swapper = 0; 2259 2260 /* 2261 * Some signals have a process-wide effect and a per-thread 2262 * component. Most processing occurs when the process next 2263 * tries to cross the user boundary, however there are some 2264 * times when processing needs to be done immediately, such as 2265 * waking up threads so that they can cross the user boundary. 2266 * We try to do the per-process part here. 2267 */ 2268 if (P_SHOULDSTOP(p)) { 2269 KASSERT(!(p->p_flag & P_WEXIT), 2270 ("signal to stopped but exiting process")); 2271 if (sig == SIGKILL) { 2272 /* 2273 * If traced process is already stopped, 2274 * then no further action is necessary. 2275 */ 2276 if (p->p_flag & P_TRACED) 2277 goto out; 2278 /* 2279 * SIGKILL sets process running. 2280 * It will die elsewhere. 2281 * All threads must be restarted. 2282 */ 2283 p->p_flag &= ~P_STOPPED_SIG; 2284 goto runfast; 2285 } 2286 2287 if (prop & SIGPROP_CONT) { 2288 /* 2289 * If traced process is already stopped, 2290 * then no further action is necessary. 2291 */ 2292 if (p->p_flag & P_TRACED) 2293 goto out; 2294 /* 2295 * If SIGCONT is default (or ignored), we continue the 2296 * process but don't leave the signal in sigqueue as 2297 * it has no further action. If SIGCONT is held, we 2298 * continue the process and leave the signal in 2299 * sigqueue. If the process catches SIGCONT, let it 2300 * handle the signal itself. If it isn't waiting on 2301 * an event, it goes back to run state. 2302 * Otherwise, process goes back to sleep state. 2303 */ 2304 p->p_flag &= ~P_STOPPED_SIG; 2305 PROC_SLOCK(p); 2306 if (p->p_numthreads == p->p_suspcount) { 2307 PROC_SUNLOCK(p); 2308 p->p_flag |= P_CONTINUED; 2309 p->p_xsig = SIGCONT; 2310 PROC_LOCK(p->p_pptr); 2311 childproc_continued(p); 2312 PROC_UNLOCK(p->p_pptr); 2313 PROC_SLOCK(p); 2314 } 2315 if (action == SIG_DFL) { 2316 thread_unsuspend(p); 2317 PROC_SUNLOCK(p); 2318 sigqueue_delete(sigqueue, sig); 2319 goto out; 2320 } 2321 if (action == SIG_CATCH) { 2322 /* 2323 * The process wants to catch it so it needs 2324 * to run at least one thread, but which one? 2325 */ 2326 PROC_SUNLOCK(p); 2327 goto runfast; 2328 } 2329 /* 2330 * The signal is not ignored or caught. 2331 */ 2332 thread_unsuspend(p); 2333 PROC_SUNLOCK(p); 2334 goto out; 2335 } 2336 2337 if (prop & SIGPROP_STOP) { 2338 /* 2339 * If traced process is already stopped, 2340 * then no further action is necessary. 2341 */ 2342 if (p->p_flag & P_TRACED) 2343 goto out; 2344 /* 2345 * Already stopped, don't need to stop again 2346 * (If we did the shell could get confused). 2347 * Just make sure the signal STOP bit set. 2348 */ 2349 p->p_flag |= P_STOPPED_SIG; 2350 sigqueue_delete(sigqueue, sig); 2351 goto out; 2352 } 2353 2354 /* 2355 * All other kinds of signals: 2356 * If a thread is sleeping interruptibly, simulate a 2357 * wakeup so that when it is continued it will be made 2358 * runnable and can look at the signal. However, don't make 2359 * the PROCESS runnable, leave it stopped. 2360 * It may run a bit until it hits a thread_suspend_check(). 2361 */ 2362 PROC_SLOCK(p); 2363 thread_lock(td); 2364 if (TD_CAN_ABORT(td)) 2365 wakeup_swapper = sleepq_abort(td, intrval); 2366 else 2367 thread_unlock(td); 2368 PROC_SUNLOCK(p); 2369 goto out; 2370 /* 2371 * Mutexes are short lived. Threads waiting on them will 2372 * hit thread_suspend_check() soon. 2373 */ 2374 } else if (p->p_state == PRS_NORMAL) { 2375 if (p->p_flag & P_TRACED || action == SIG_CATCH) { 2376 tdsigwakeup(td, sig, action, intrval); 2377 goto out; 2378 } 2379 2380 MPASS(action == SIG_DFL); 2381 2382 if (prop & SIGPROP_STOP) { 2383 if (p->p_flag & (P_PPWAIT|P_WEXIT)) 2384 goto out; 2385 p->p_flag |= P_STOPPED_SIG; 2386 p->p_xsig = sig; 2387 PROC_SLOCK(p); 2388 wakeup_swapper = sig_suspend_threads(td, p, 1); 2389 if (p->p_numthreads == p->p_suspcount) { 2390 /* 2391 * only thread sending signal to another 2392 * process can reach here, if thread is sending 2393 * signal to its process, because thread does 2394 * not suspend itself here, p_numthreads 2395 * should never be equal to p_suspcount. 2396 */ 2397 thread_stopped(p); 2398 PROC_SUNLOCK(p); 2399 sigqueue_delete_proc(p, p->p_xsig); 2400 } else 2401 PROC_SUNLOCK(p); 2402 goto out; 2403 } 2404 } else { 2405 /* Not in "NORMAL" state. discard the signal. */ 2406 sigqueue_delete(sigqueue, sig); 2407 goto out; 2408 } 2409 2410 /* 2411 * The process is not stopped so we need to apply the signal to all the 2412 * running threads. 2413 */ 2414 runfast: 2415 tdsigwakeup(td, sig, action, intrval); 2416 PROC_SLOCK(p); 2417 thread_unsuspend(p); 2418 PROC_SUNLOCK(p); 2419 out: 2420 /* If we jump here, proc slock should not be owned. */ 2421 PROC_SLOCK_ASSERT(p, MA_NOTOWNED); 2422 if (wakeup_swapper) 2423 kick_proc0(); 2424 2425 return (ret); 2426 } 2427 2428 /* 2429 * The force of a signal has been directed against a single 2430 * thread. We need to see what we can do about knocking it 2431 * out of any sleep it may be in etc. 2432 */ 2433 static void 2434 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval) 2435 { 2436 struct proc *p = td->td_proc; 2437 int prop, wakeup_swapper; 2438 2439 PROC_LOCK_ASSERT(p, MA_OWNED); 2440 prop = sigprop(sig); 2441 2442 PROC_SLOCK(p); 2443 thread_lock(td); 2444 /* 2445 * Bring the priority of a thread up if we want it to get 2446 * killed in this lifetime. Be careful to avoid bumping the 2447 * priority of the idle thread, since we still allow to signal 2448 * kernel processes. 2449 */ 2450 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 && 2451 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2452 sched_prio(td, PUSER); 2453 if (TD_ON_SLEEPQ(td)) { 2454 /* 2455 * If thread is sleeping uninterruptibly 2456 * we can't interrupt the sleep... the signal will 2457 * be noticed when the process returns through 2458 * trap() or syscall(). 2459 */ 2460 if ((td->td_flags & TDF_SINTR) == 0) 2461 goto out; 2462 /* 2463 * If SIGCONT is default (or ignored) and process is 2464 * asleep, we are finished; the process should not 2465 * be awakened. 2466 */ 2467 if ((prop & SIGPROP_CONT) && action == SIG_DFL) { 2468 thread_unlock(td); 2469 PROC_SUNLOCK(p); 2470 sigqueue_delete(&p->p_sigqueue, sig); 2471 /* 2472 * It may be on either list in this state. 2473 * Remove from both for now. 2474 */ 2475 sigqueue_delete(&td->td_sigqueue, sig); 2476 return; 2477 } 2478 2479 /* 2480 * Don't awaken a sleeping thread for SIGSTOP if the 2481 * STOP signal is deferred. 2482 */ 2483 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY | 2484 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2485 goto out; 2486 2487 /* 2488 * Give low priority threads a better chance to run. 2489 */ 2490 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2491 sched_prio(td, PUSER); 2492 2493 wakeup_swapper = sleepq_abort(td, intrval); 2494 PROC_SUNLOCK(p); 2495 if (wakeup_swapper) 2496 kick_proc0(); 2497 return; 2498 } 2499 2500 /* 2501 * Other states do nothing with the signal immediately, 2502 * other than kicking ourselves if we are running. 2503 * It will either never be noticed, or noticed very soon. 2504 */ 2505 #ifdef SMP 2506 if (TD_IS_RUNNING(td) && td != curthread) 2507 forward_signal(td); 2508 #endif 2509 2510 out: 2511 PROC_SUNLOCK(p); 2512 thread_unlock(td); 2513 } 2514 2515 static int 2516 sig_suspend_threads(struct thread *td, struct proc *p, int sending) 2517 { 2518 struct thread *td2; 2519 int wakeup_swapper; 2520 2521 PROC_LOCK_ASSERT(p, MA_OWNED); 2522 PROC_SLOCK_ASSERT(p, MA_OWNED); 2523 MPASS(sending || td == curthread); 2524 2525 wakeup_swapper = 0; 2526 FOREACH_THREAD_IN_PROC(p, td2) { 2527 thread_lock(td2); 2528 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK; 2529 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) && 2530 (td2->td_flags & TDF_SINTR)) { 2531 if (td2->td_flags & TDF_SBDRY) { 2532 /* 2533 * Once a thread is asleep with 2534 * TDF_SBDRY and without TDF_SERESTART 2535 * or TDF_SEINTR set, it should never 2536 * become suspended due to this check. 2537 */ 2538 KASSERT(!TD_IS_SUSPENDED(td2), 2539 ("thread with deferred stops suspended")); 2540 if (TD_SBDRY_INTR(td2)) { 2541 wakeup_swapper |= sleepq_abort(td2, 2542 TD_SBDRY_ERRNO(td2)); 2543 continue; 2544 } 2545 } else if (!TD_IS_SUSPENDED(td2)) 2546 thread_suspend_one(td2); 2547 } else if (!TD_IS_SUSPENDED(td2)) { 2548 if (sending || td != td2) 2549 td2->td_flags |= TDF_ASTPENDING; 2550 #ifdef SMP 2551 if (TD_IS_RUNNING(td2) && td2 != td) 2552 forward_signal(td2); 2553 #endif 2554 } 2555 thread_unlock(td2); 2556 } 2557 return (wakeup_swapper); 2558 } 2559 2560 /* 2561 * Stop the process for an event deemed interesting to the debugger. If si is 2562 * non-NULL, this is a signal exchange; the new signal requested by the 2563 * debugger will be returned for handling. If si is NULL, this is some other 2564 * type of interesting event. The debugger may request a signal be delivered in 2565 * that case as well, however it will be deferred until it can be handled. 2566 */ 2567 int 2568 ptracestop(struct thread *td, int sig, ksiginfo_t *si) 2569 { 2570 struct proc *p = td->td_proc; 2571 struct thread *td2; 2572 ksiginfo_t ksi; 2573 2574 PROC_LOCK_ASSERT(p, MA_OWNED); 2575 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); 2576 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2577 &p->p_mtx.lock_object, "Stopping for traced signal"); 2578 2579 td->td_xsig = sig; 2580 2581 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) { 2582 td->td_dbgflags |= TDB_XSIG; 2583 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d", 2584 td->td_tid, p->p_pid, td->td_dbgflags, sig); 2585 PROC_SLOCK(p); 2586 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) { 2587 if (P_KILLED(p)) { 2588 /* 2589 * Ensure that, if we've been PT_KILLed, the 2590 * exit status reflects that. Another thread 2591 * may also be in ptracestop(), having just 2592 * received the SIGKILL, but this thread was 2593 * unsuspended first. 2594 */ 2595 td->td_dbgflags &= ~TDB_XSIG; 2596 td->td_xsig = SIGKILL; 2597 p->p_ptevents = 0; 2598 break; 2599 } 2600 if (p->p_flag & P_SINGLE_EXIT && 2601 !(td->td_dbgflags & TDB_EXIT)) { 2602 /* 2603 * Ignore ptrace stops except for thread exit 2604 * events when the process exits. 2605 */ 2606 td->td_dbgflags &= ~TDB_XSIG; 2607 PROC_SUNLOCK(p); 2608 return (0); 2609 } 2610 2611 /* 2612 * Make wait(2) work. Ensure that right after the 2613 * attach, the thread which was decided to become the 2614 * leader of attach gets reported to the waiter. 2615 * Otherwise, just avoid overwriting another thread's 2616 * assignment to p_xthread. If another thread has 2617 * already set p_xthread, the current thread will get 2618 * a chance to report itself upon the next iteration. 2619 */ 2620 if ((td->td_dbgflags & TDB_FSTP) != 0 || 2621 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 && 2622 p->p_xthread == NULL)) { 2623 p->p_xsig = sig; 2624 p->p_xthread = td; 2625 2626 /* 2627 * If we are on sleepqueue already, 2628 * let sleepqueue code decide if it 2629 * needs to go sleep after attach. 2630 */ 2631 if (td->td_wchan == NULL) 2632 td->td_dbgflags &= ~TDB_FSTP; 2633 2634 p->p_flag2 &= ~P2_PTRACE_FSTP; 2635 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE; 2636 sig_suspend_threads(td, p, 0); 2637 } 2638 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) { 2639 td->td_dbgflags &= ~TDB_STOPATFORK; 2640 } 2641 stopme: 2642 thread_suspend_switch(td, p); 2643 if (p->p_xthread == td) 2644 p->p_xthread = NULL; 2645 if (!(p->p_flag & P_TRACED)) 2646 break; 2647 if (td->td_dbgflags & TDB_SUSPEND) { 2648 if (p->p_flag & P_SINGLE_EXIT) 2649 break; 2650 goto stopme; 2651 } 2652 } 2653 PROC_SUNLOCK(p); 2654 } 2655 2656 if (si != NULL && sig == td->td_xsig) { 2657 /* Parent wants us to take the original signal unchanged. */ 2658 si->ksi_flags |= KSI_HEAD; 2659 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0) 2660 si->ksi_signo = 0; 2661 } else if (td->td_xsig != 0) { 2662 /* 2663 * If parent wants us to take a new signal, then it will leave 2664 * it in td->td_xsig; otherwise we just look for signals again. 2665 */ 2666 ksiginfo_init(&ksi); 2667 ksi.ksi_signo = td->td_xsig; 2668 ksi.ksi_flags |= KSI_PTRACE; 2669 td2 = sigtd(p, td->td_xsig, false); 2670 tdsendsignal(p, td2, td->td_xsig, &ksi); 2671 if (td != td2) 2672 return (0); 2673 } 2674 2675 return (td->td_xsig); 2676 } 2677 2678 static void 2679 reschedule_signals(struct proc *p, sigset_t block, int flags) 2680 { 2681 struct sigacts *ps; 2682 struct thread *td; 2683 int sig; 2684 bool fastblk, pslocked; 2685 2686 PROC_LOCK_ASSERT(p, MA_OWNED); 2687 ps = p->p_sigacts; 2688 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0; 2689 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED); 2690 if (SIGISEMPTY(p->p_siglist)) 2691 return; 2692 SIGSETAND(block, p->p_siglist); 2693 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0; 2694 while ((sig = sig_ffs(&block)) != 0) { 2695 SIGDELSET(block, sig); 2696 td = sigtd(p, sig, fastblk); 2697 2698 /* 2699 * If sigtd() selected us despite sigfastblock is 2700 * blocking, do not activate AST or wake us, to avoid 2701 * loop in AST handler. 2702 */ 2703 if (fastblk && td == curthread) 2704 continue; 2705 2706 signotify(td); 2707 if (!pslocked) 2708 mtx_lock(&ps->ps_mtx); 2709 if (p->p_flag & P_TRACED || 2710 (SIGISMEMBER(ps->ps_sigcatch, sig) && 2711 !SIGISMEMBER(td->td_sigmask, sig))) { 2712 tdsigwakeup(td, sig, SIG_CATCH, 2713 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : 2714 ERESTART)); 2715 } 2716 if (!pslocked) 2717 mtx_unlock(&ps->ps_mtx); 2718 } 2719 } 2720 2721 void 2722 tdsigcleanup(struct thread *td) 2723 { 2724 struct proc *p; 2725 sigset_t unblocked; 2726 2727 p = td->td_proc; 2728 PROC_LOCK_ASSERT(p, MA_OWNED); 2729 2730 sigqueue_flush(&td->td_sigqueue); 2731 if (p->p_numthreads == 1) 2732 return; 2733 2734 /* 2735 * Since we cannot handle signals, notify signal post code 2736 * about this by filling the sigmask. 2737 * 2738 * Also, if needed, wake up thread(s) that do not block the 2739 * same signals as the exiting thread, since the thread might 2740 * have been selected for delivery and woken up. 2741 */ 2742 SIGFILLSET(unblocked); 2743 SIGSETNAND(unblocked, td->td_sigmask); 2744 SIGFILLSET(td->td_sigmask); 2745 reschedule_signals(p, unblocked, 0); 2746 2747 } 2748 2749 static int 2750 sigdeferstop_curr_flags(int cflags) 2751 { 2752 2753 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 || 2754 (cflags & TDF_SBDRY) != 0); 2755 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)); 2756 } 2757 2758 /* 2759 * Defer the delivery of SIGSTOP for the current thread, according to 2760 * the requested mode. Returns previous flags, which must be restored 2761 * by sigallowstop(). 2762 * 2763 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and 2764 * cleared by the current thread, which allow the lock-less read-only 2765 * accesses below. 2766 */ 2767 int 2768 sigdeferstop_impl(int mode) 2769 { 2770 struct thread *td; 2771 int cflags, nflags; 2772 2773 td = curthread; 2774 cflags = sigdeferstop_curr_flags(td->td_flags); 2775 switch (mode) { 2776 case SIGDEFERSTOP_NOP: 2777 nflags = cflags; 2778 break; 2779 case SIGDEFERSTOP_OFF: 2780 nflags = 0; 2781 break; 2782 case SIGDEFERSTOP_SILENT: 2783 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART); 2784 break; 2785 case SIGDEFERSTOP_EINTR: 2786 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART; 2787 break; 2788 case SIGDEFERSTOP_ERESTART: 2789 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR; 2790 break; 2791 default: 2792 panic("sigdeferstop: invalid mode %x", mode); 2793 break; 2794 } 2795 if (cflags == nflags) 2796 return (SIGDEFERSTOP_VAL_NCHG); 2797 thread_lock(td); 2798 td->td_flags = (td->td_flags & ~cflags) | nflags; 2799 thread_unlock(td); 2800 return (cflags); 2801 } 2802 2803 /* 2804 * Restores the STOP handling mode, typically permitting the delivery 2805 * of SIGSTOP for the current thread. This does not immediately 2806 * suspend if a stop was posted. Instead, the thread will suspend 2807 * either via ast() or a subsequent interruptible sleep. 2808 */ 2809 void 2810 sigallowstop_impl(int prev) 2811 { 2812 struct thread *td; 2813 int cflags; 2814 2815 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop")); 2816 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0, 2817 ("sigallowstop: incorrect previous mode %x", prev)); 2818 td = curthread; 2819 cflags = sigdeferstop_curr_flags(td->td_flags); 2820 if (cflags != prev) { 2821 thread_lock(td); 2822 td->td_flags = (td->td_flags & ~cflags) | prev; 2823 thread_unlock(td); 2824 } 2825 } 2826 2827 /* 2828 * If the current process has received a signal (should be caught or cause 2829 * termination, should interrupt current syscall), return the signal number. 2830 * Stop signals with default action are processed immediately, then cleared; 2831 * they aren't returned. This is checked after each entry to the system for 2832 * a syscall or trap (though this can usually be done without calling issignal 2833 * by checking the pending signal masks in cursig.) The normal call 2834 * sequence is 2835 * 2836 * while (sig = cursig(curthread)) 2837 * postsig(sig); 2838 */ 2839 static int 2840 issignal(struct thread *td) 2841 { 2842 struct proc *p; 2843 struct sigacts *ps; 2844 struct sigqueue *queue; 2845 sigset_t sigpending; 2846 ksiginfo_t ksi; 2847 int prop, sig; 2848 2849 p = td->td_proc; 2850 ps = p->p_sigacts; 2851 mtx_assert(&ps->ps_mtx, MA_OWNED); 2852 PROC_LOCK_ASSERT(p, MA_OWNED); 2853 for (;;) { 2854 sigpending = td->td_sigqueue.sq_signals; 2855 SIGSETOR(sigpending, p->p_sigqueue.sq_signals); 2856 SIGSETNAND(sigpending, td->td_sigmask); 2857 2858 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags & 2859 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2860 SIG_STOPSIGMASK(sigpending); 2861 if (SIGISEMPTY(sigpending)) /* no signal to send */ 2862 return (0); 2863 2864 /* 2865 * Do fast sigblock if requested by usermode. Since 2866 * we do know that there was a signal pending at this 2867 * point, set the FAST_SIGBLOCK_PEND as indicator for 2868 * usermode to perform a dummy call to 2869 * FAST_SIGBLOCK_UNBLOCK, which causes immediate 2870 * delivery of postponed pending signal. 2871 */ 2872 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 2873 if (td->td_sigblock_val != 0) 2874 SIGSETNAND(sigpending, fastblock_mask); 2875 if (SIGISEMPTY(sigpending)) { 2876 td->td_pflags |= TDP_SIGFASTPENDING; 2877 return (0); 2878 } 2879 } 2880 2881 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED && 2882 (p->p_flag2 & P2_PTRACE_FSTP) != 0 && 2883 SIGISMEMBER(sigpending, SIGSTOP)) { 2884 /* 2885 * If debugger just attached, always consume 2886 * SIGSTOP from ptrace(PT_ATTACH) first, to 2887 * execute the debugger attach ritual in 2888 * order. 2889 */ 2890 sig = SIGSTOP; 2891 td->td_dbgflags |= TDB_FSTP; 2892 } else { 2893 sig = sig_ffs(&sigpending); 2894 } 2895 2896 /* 2897 * We should see pending but ignored signals 2898 * only if P_TRACED was on when they were posted. 2899 */ 2900 if (SIGISMEMBER(ps->ps_sigignore, sig) && 2901 (p->p_flag & P_TRACED) == 0) { 2902 sigqueue_delete(&td->td_sigqueue, sig); 2903 sigqueue_delete(&p->p_sigqueue, sig); 2904 continue; 2905 } 2906 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) { 2907 /* 2908 * If traced, always stop. 2909 * Remove old signal from queue before the stop. 2910 * XXX shrug off debugger, it causes siginfo to 2911 * be thrown away. 2912 */ 2913 queue = &td->td_sigqueue; 2914 ksiginfo_init(&ksi); 2915 if (sigqueue_get(queue, sig, &ksi) == 0) { 2916 queue = &p->p_sigqueue; 2917 sigqueue_get(queue, sig, &ksi); 2918 } 2919 td->td_si = ksi.ksi_info; 2920 2921 mtx_unlock(&ps->ps_mtx); 2922 sig = ptracestop(td, sig, &ksi); 2923 mtx_lock(&ps->ps_mtx); 2924 2925 td->td_si.si_signo = 0; 2926 2927 /* 2928 * Keep looking if the debugger discarded or 2929 * replaced the signal. 2930 */ 2931 if (sig == 0) 2932 continue; 2933 2934 /* 2935 * If the signal became masked, re-queue it. 2936 */ 2937 if (SIGISMEMBER(td->td_sigmask, sig)) { 2938 ksi.ksi_flags |= KSI_HEAD; 2939 sigqueue_add(&p->p_sigqueue, sig, &ksi); 2940 continue; 2941 } 2942 2943 /* 2944 * If the traced bit got turned off, requeue 2945 * the signal and go back up to the top to 2946 * rescan signals. This ensures that p_sig* 2947 * and p_sigact are consistent. 2948 */ 2949 if ((p->p_flag & P_TRACED) == 0) { 2950 ksi.ksi_flags |= KSI_HEAD; 2951 sigqueue_add(queue, sig, &ksi); 2952 continue; 2953 } 2954 } 2955 2956 prop = sigprop(sig); 2957 2958 /* 2959 * Decide whether the signal should be returned. 2960 * Return the signal's number, or fall through 2961 * to clear it from the pending mask. 2962 */ 2963 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2964 case (intptr_t)SIG_DFL: 2965 /* 2966 * Don't take default actions on system processes. 2967 */ 2968 if (p->p_pid <= 1) { 2969 #ifdef DIAGNOSTIC 2970 /* 2971 * Are you sure you want to ignore SIGSEGV 2972 * in init? XXX 2973 */ 2974 printf("Process (pid %lu) got signal %d\n", 2975 (u_long)p->p_pid, sig); 2976 #endif 2977 break; /* == ignore */ 2978 } 2979 /* 2980 * If there is a pending stop signal to process with 2981 * default action, stop here, then clear the signal. 2982 * Traced or exiting processes should ignore stops. 2983 * Additionally, a member of an orphaned process group 2984 * should ignore tty stops. 2985 */ 2986 if (prop & SIGPROP_STOP) { 2987 if (p->p_flag & 2988 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) || 2989 (p->p_pgrp->pg_jobc == 0 && 2990 prop & SIGPROP_TTYSTOP)) 2991 break; /* == ignore */ 2992 if (TD_SBDRY_INTR(td)) { 2993 KASSERT((td->td_flags & TDF_SBDRY) != 0, 2994 ("lost TDF_SBDRY")); 2995 return (-1); 2996 } 2997 mtx_unlock(&ps->ps_mtx); 2998 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2999 &p->p_mtx.lock_object, "Catching SIGSTOP"); 3000 sigqueue_delete(&td->td_sigqueue, sig); 3001 sigqueue_delete(&p->p_sigqueue, sig); 3002 p->p_flag |= P_STOPPED_SIG; 3003 p->p_xsig = sig; 3004 PROC_SLOCK(p); 3005 sig_suspend_threads(td, p, 0); 3006 thread_suspend_switch(td, p); 3007 PROC_SUNLOCK(p); 3008 mtx_lock(&ps->ps_mtx); 3009 goto next; 3010 } else if (prop & SIGPROP_IGNORE) { 3011 /* 3012 * Except for SIGCONT, shouldn't get here. 3013 * Default action is to ignore; drop it. 3014 */ 3015 break; /* == ignore */ 3016 } else 3017 return (sig); 3018 /*NOTREACHED*/ 3019 3020 case (intptr_t)SIG_IGN: 3021 /* 3022 * Masking above should prevent us ever trying 3023 * to take action on an ignored signal other 3024 * than SIGCONT, unless process is traced. 3025 */ 3026 if ((prop & SIGPROP_CONT) == 0 && 3027 (p->p_flag & P_TRACED) == 0) 3028 printf("issignal\n"); 3029 break; /* == ignore */ 3030 3031 default: 3032 /* 3033 * This signal has an action, let 3034 * postsig() process it. 3035 */ 3036 return (sig); 3037 } 3038 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */ 3039 sigqueue_delete(&p->p_sigqueue, sig); 3040 next:; 3041 } 3042 /* NOTREACHED */ 3043 } 3044 3045 void 3046 thread_stopped(struct proc *p) 3047 { 3048 int n; 3049 3050 PROC_LOCK_ASSERT(p, MA_OWNED); 3051 PROC_SLOCK_ASSERT(p, MA_OWNED); 3052 n = p->p_suspcount; 3053 if (p == curproc) 3054 n++; 3055 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) { 3056 PROC_SUNLOCK(p); 3057 p->p_flag &= ~P_WAITED; 3058 PROC_LOCK(p->p_pptr); 3059 childproc_stopped(p, (p->p_flag & P_TRACED) ? 3060 CLD_TRAPPED : CLD_STOPPED); 3061 PROC_UNLOCK(p->p_pptr); 3062 PROC_SLOCK(p); 3063 } 3064 } 3065 3066 /* 3067 * Take the action for the specified signal 3068 * from the current set of pending signals. 3069 */ 3070 int 3071 postsig(int sig) 3072 { 3073 struct thread *td; 3074 struct proc *p; 3075 struct sigacts *ps; 3076 sig_t action; 3077 ksiginfo_t ksi; 3078 sigset_t returnmask; 3079 3080 KASSERT(sig != 0, ("postsig")); 3081 3082 td = curthread; 3083 p = td->td_proc; 3084 PROC_LOCK_ASSERT(p, MA_OWNED); 3085 ps = p->p_sigacts; 3086 mtx_assert(&ps->ps_mtx, MA_OWNED); 3087 ksiginfo_init(&ksi); 3088 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 && 3089 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0) 3090 return (0); 3091 ksi.ksi_signo = sig; 3092 if (ksi.ksi_code == SI_TIMER) 3093 itimer_accept(p, ksi.ksi_timerid, &ksi); 3094 action = ps->ps_sigact[_SIG_IDX(sig)]; 3095 #ifdef KTRACE 3096 if (KTRPOINT(td, KTR_PSIG)) 3097 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ? 3098 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code); 3099 #endif 3100 3101 if (action == SIG_DFL) { 3102 /* 3103 * Default action, where the default is to kill 3104 * the process. (Other cases were ignored above.) 3105 */ 3106 mtx_unlock(&ps->ps_mtx); 3107 proc_td_siginfo_capture(td, &ksi.ksi_info); 3108 sigexit(td, sig); 3109 /* NOTREACHED */ 3110 } else { 3111 /* 3112 * If we get here, the signal must be caught. 3113 */ 3114 KASSERT(action != SIG_IGN, ("postsig action %p", action)); 3115 KASSERT(!SIGISMEMBER(td->td_sigmask, sig), 3116 ("postsig action: blocked sig %d", sig)); 3117 3118 /* 3119 * Set the new mask value and also defer further 3120 * occurrences of this signal. 3121 * 3122 * Special case: user has done a sigsuspend. Here the 3123 * current mask is not of interest, but rather the 3124 * mask from before the sigsuspend is what we want 3125 * restored after the signal processing is completed. 3126 */ 3127 if (td->td_pflags & TDP_OLDMASK) { 3128 returnmask = td->td_oldsigmask; 3129 td->td_pflags &= ~TDP_OLDMASK; 3130 } else 3131 returnmask = td->td_sigmask; 3132 3133 if (p->p_sig == sig) { 3134 p->p_sig = 0; 3135 } 3136 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask); 3137 postsig_done(sig, td, ps); 3138 } 3139 return (1); 3140 } 3141 3142 void 3143 proc_wkilled(struct proc *p) 3144 { 3145 3146 PROC_LOCK_ASSERT(p, MA_OWNED); 3147 if ((p->p_flag & P_WKILLED) == 0) { 3148 p->p_flag |= P_WKILLED; 3149 /* 3150 * Notify swapper that there is a process to swap in. 3151 * The notification is racy, at worst it would take 10 3152 * seconds for the swapper process to notice. 3153 */ 3154 if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0) 3155 wakeup(&proc0); 3156 } 3157 } 3158 3159 /* 3160 * Kill the current process for stated reason. 3161 */ 3162 void 3163 killproc(struct proc *p, const char *why) 3164 { 3165 3166 PROC_LOCK_ASSERT(p, MA_OWNED); 3167 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid, 3168 p->p_comm); 3169 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n", 3170 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id, 3171 p->p_ucred->cr_uid, why); 3172 proc_wkilled(p); 3173 kern_psignal(p, SIGKILL); 3174 } 3175 3176 /* 3177 * Force the current process to exit with the specified signal, dumping core 3178 * if appropriate. We bypass the normal tests for masked and caught signals, 3179 * allowing unrecoverable failures to terminate the process without changing 3180 * signal state. Mark the accounting record with the signal termination. 3181 * If dumping core, save the signal number for the debugger. Calls exit and 3182 * does not return. 3183 */ 3184 void 3185 sigexit(struct thread *td, int sig) 3186 { 3187 struct proc *p = td->td_proc; 3188 3189 PROC_LOCK_ASSERT(p, MA_OWNED); 3190 p->p_acflag |= AXSIG; 3191 /* 3192 * We must be single-threading to generate a core dump. This 3193 * ensures that the registers in the core file are up-to-date. 3194 * Also, the ELF dump handler assumes that the thread list doesn't 3195 * change out from under it. 3196 * 3197 * XXX If another thread attempts to single-thread before us 3198 * (e.g. via fork()), we won't get a dump at all. 3199 */ 3200 if ((sigprop(sig) & SIGPROP_CORE) && 3201 thread_single(p, SINGLE_NO_EXIT) == 0) { 3202 p->p_sig = sig; 3203 /* 3204 * Log signals which would cause core dumps 3205 * (Log as LOG_INFO to appease those who don't want 3206 * these messages.) 3207 * XXX : Todo, as well as euid, write out ruid too 3208 * Note that coredump() drops proc lock. 3209 */ 3210 if (coredump(td) == 0) 3211 sig |= WCOREFLAG; 3212 if (kern_logsigexit) 3213 log(LOG_INFO, 3214 "pid %d (%s), jid %d, uid %d: exited on " 3215 "signal %d%s\n", p->p_pid, p->p_comm, 3216 p->p_ucred->cr_prison->pr_id, 3217 td->td_ucred->cr_uid, 3218 sig &~ WCOREFLAG, 3219 sig & WCOREFLAG ? " (core dumped)" : ""); 3220 } else 3221 PROC_UNLOCK(p); 3222 exit1(td, 0, sig); 3223 /* NOTREACHED */ 3224 } 3225 3226 /* 3227 * Send queued SIGCHLD to parent when child process's state 3228 * is changed. 3229 */ 3230 static void 3231 sigparent(struct proc *p, int reason, int status) 3232 { 3233 PROC_LOCK_ASSERT(p, MA_OWNED); 3234 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3235 3236 if (p->p_ksi != NULL) { 3237 p->p_ksi->ksi_signo = SIGCHLD; 3238 p->p_ksi->ksi_code = reason; 3239 p->p_ksi->ksi_status = status; 3240 p->p_ksi->ksi_pid = p->p_pid; 3241 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid; 3242 if (KSI_ONQ(p->p_ksi)) 3243 return; 3244 } 3245 pksignal(p->p_pptr, SIGCHLD, p->p_ksi); 3246 } 3247 3248 static void 3249 childproc_jobstate(struct proc *p, int reason, int sig) 3250 { 3251 struct sigacts *ps; 3252 3253 PROC_LOCK_ASSERT(p, MA_OWNED); 3254 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3255 3256 /* 3257 * Wake up parent sleeping in kern_wait(), also send 3258 * SIGCHLD to parent, but SIGCHLD does not guarantee 3259 * that parent will awake, because parent may masked 3260 * the signal. 3261 */ 3262 p->p_pptr->p_flag |= P_STATCHILD; 3263 wakeup(p->p_pptr); 3264 3265 ps = p->p_pptr->p_sigacts; 3266 mtx_lock(&ps->ps_mtx); 3267 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) { 3268 mtx_unlock(&ps->ps_mtx); 3269 sigparent(p, reason, sig); 3270 } else 3271 mtx_unlock(&ps->ps_mtx); 3272 } 3273 3274 void 3275 childproc_stopped(struct proc *p, int reason) 3276 { 3277 3278 childproc_jobstate(p, reason, p->p_xsig); 3279 } 3280 3281 void 3282 childproc_continued(struct proc *p) 3283 { 3284 childproc_jobstate(p, CLD_CONTINUED, SIGCONT); 3285 } 3286 3287 void 3288 childproc_exited(struct proc *p) 3289 { 3290 int reason, status; 3291 3292 if (WCOREDUMP(p->p_xsig)) { 3293 reason = CLD_DUMPED; 3294 status = WTERMSIG(p->p_xsig); 3295 } else if (WIFSIGNALED(p->p_xsig)) { 3296 reason = CLD_KILLED; 3297 status = WTERMSIG(p->p_xsig); 3298 } else { 3299 reason = CLD_EXITED; 3300 status = p->p_xexit; 3301 } 3302 /* 3303 * XXX avoid calling wakeup(p->p_pptr), the work is 3304 * done in exit1(). 3305 */ 3306 sigparent(p, reason, status); 3307 } 3308 3309 #define MAX_NUM_CORE_FILES 100000 3310 #ifndef NUM_CORE_FILES 3311 #define NUM_CORE_FILES 5 3312 #endif 3313 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES); 3314 static int num_cores = NUM_CORE_FILES; 3315 3316 static int 3317 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS) 3318 { 3319 int error; 3320 int new_val; 3321 3322 new_val = num_cores; 3323 error = sysctl_handle_int(oidp, &new_val, 0, req); 3324 if (error != 0 || req->newptr == NULL) 3325 return (error); 3326 if (new_val > MAX_NUM_CORE_FILES) 3327 new_val = MAX_NUM_CORE_FILES; 3328 if (new_val < 0) 3329 new_val = 0; 3330 num_cores = new_val; 3331 return (0); 3332 } 3333 SYSCTL_PROC(_debug, OID_AUTO, ncores, 3334 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(int), 3335 sysctl_debug_num_cores_check, "I", 3336 "Maximum number of generated process corefiles while using index format"); 3337 3338 #define GZIP_SUFFIX ".gz" 3339 #define ZSTD_SUFFIX ".zst" 3340 3341 int compress_user_cores = 0; 3342 3343 static int 3344 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS) 3345 { 3346 int error, val; 3347 3348 val = compress_user_cores; 3349 error = sysctl_handle_int(oidp, &val, 0, req); 3350 if (error != 0 || req->newptr == NULL) 3351 return (error); 3352 if (val != 0 && !compressor_avail(val)) 3353 return (EINVAL); 3354 compress_user_cores = val; 3355 return (error); 3356 } 3357 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores, 3358 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int), 3359 sysctl_compress_user_cores, "I", 3360 "Enable compression of user corefiles (" 3361 __XSTRING(COMPRESS_GZIP) " = gzip, " 3362 __XSTRING(COMPRESS_ZSTD) " = zstd)"); 3363 3364 int compress_user_cores_level = 6; 3365 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN, 3366 &compress_user_cores_level, 0, 3367 "Corefile compression level"); 3368 3369 /* 3370 * Protect the access to corefilename[] by allproc_lock. 3371 */ 3372 #define corefilename_lock allproc_lock 3373 3374 static char corefilename[MAXPATHLEN] = {"%N.core"}; 3375 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename)); 3376 3377 static int 3378 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS) 3379 { 3380 int error; 3381 3382 sx_xlock(&corefilename_lock); 3383 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename), 3384 req); 3385 sx_xunlock(&corefilename_lock); 3386 3387 return (error); 3388 } 3389 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW | 3390 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", 3391 "Process corefile name format string"); 3392 3393 static void 3394 vnode_close_locked(struct thread *td, struct vnode *vp) 3395 { 3396 3397 VOP_UNLOCK(vp); 3398 vn_close(vp, FWRITE, td->td_ucred, td); 3399 } 3400 3401 /* 3402 * If the core format has a %I in it, then we need to check 3403 * for existing corefiles before defining a name. 3404 * To do this we iterate over 0..ncores to find a 3405 * non-existing core file name to use. If all core files are 3406 * already used we choose the oldest one. 3407 */ 3408 static int 3409 corefile_open_last(struct thread *td, char *name, int indexpos, 3410 int indexlen, int ncores, struct vnode **vpp) 3411 { 3412 struct vnode *oldvp, *nextvp, *vp; 3413 struct vattr vattr; 3414 struct nameidata nd; 3415 int error, i, flags, oflags, cmode; 3416 char ch; 3417 struct timespec lasttime; 3418 3419 nextvp = oldvp = NULL; 3420 cmode = S_IRUSR | S_IWUSR; 3421 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3422 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3423 3424 for (i = 0; i < ncores; i++) { 3425 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3426 3427 ch = name[indexpos + indexlen]; 3428 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen, 3429 i); 3430 name[indexpos + indexlen] = ch; 3431 3432 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3433 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 3434 NULL); 3435 if (error != 0) 3436 break; 3437 3438 vp = nd.ni_vp; 3439 NDFREE(&nd, NDF_ONLY_PNBUF); 3440 if ((flags & O_CREAT) == O_CREAT) { 3441 nextvp = vp; 3442 break; 3443 } 3444 3445 error = VOP_GETATTR(vp, &vattr, td->td_ucred); 3446 if (error != 0) { 3447 vnode_close_locked(td, vp); 3448 break; 3449 } 3450 3451 if (oldvp == NULL || 3452 lasttime.tv_sec > vattr.va_mtime.tv_sec || 3453 (lasttime.tv_sec == vattr.va_mtime.tv_sec && 3454 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) { 3455 if (oldvp != NULL) 3456 vn_close(oldvp, FWRITE, td->td_ucred, td); 3457 oldvp = vp; 3458 VOP_UNLOCK(oldvp); 3459 lasttime = vattr.va_mtime; 3460 } else { 3461 vnode_close_locked(td, vp); 3462 } 3463 } 3464 3465 if (oldvp != NULL) { 3466 if (nextvp == NULL) { 3467 if ((td->td_proc->p_flag & P_SUGID) != 0) { 3468 error = EFAULT; 3469 vn_close(oldvp, FWRITE, td->td_ucred, td); 3470 } else { 3471 nextvp = oldvp; 3472 error = vn_lock(nextvp, LK_EXCLUSIVE); 3473 if (error != 0) { 3474 vn_close(nextvp, FWRITE, td->td_ucred, 3475 td); 3476 nextvp = NULL; 3477 } 3478 } 3479 } else { 3480 vn_close(oldvp, FWRITE, td->td_ucred, td); 3481 } 3482 } 3483 if (error != 0) { 3484 if (nextvp != NULL) 3485 vnode_close_locked(td, oldvp); 3486 } else { 3487 *vpp = nextvp; 3488 } 3489 3490 return (error); 3491 } 3492 3493 /* 3494 * corefile_open(comm, uid, pid, td, compress, vpp, namep) 3495 * Expand the name described in corefilename, using name, uid, and pid 3496 * and open/create core file. 3497 * corefilename is a printf-like string, with three format specifiers: 3498 * %N name of process ("name") 3499 * %P process id (pid) 3500 * %U user id (uid) 3501 * For example, "%N.core" is the default; they can be disabled completely 3502 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 3503 * This is controlled by the sysctl variable kern.corefile (see above). 3504 */ 3505 static int 3506 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, 3507 int compress, int signum, struct vnode **vpp, char **namep) 3508 { 3509 struct sbuf sb; 3510 struct nameidata nd; 3511 const char *format; 3512 char *hostname, *name; 3513 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores; 3514 3515 hostname = NULL; 3516 format = corefilename; 3517 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO); 3518 indexlen = 0; 3519 indexpos = -1; 3520 ncores = num_cores; 3521 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN); 3522 sx_slock(&corefilename_lock); 3523 for (i = 0; format[i] != '\0'; i++) { 3524 switch (format[i]) { 3525 case '%': /* Format character */ 3526 i++; 3527 switch (format[i]) { 3528 case '%': 3529 sbuf_putc(&sb, '%'); 3530 break; 3531 case 'H': /* hostname */ 3532 if (hostname == NULL) { 3533 hostname = malloc(MAXHOSTNAMELEN, 3534 M_TEMP, M_WAITOK); 3535 } 3536 getcredhostname(td->td_ucred, hostname, 3537 MAXHOSTNAMELEN); 3538 sbuf_printf(&sb, "%s", hostname); 3539 break; 3540 case 'I': /* autoincrementing index */ 3541 if (indexpos != -1) { 3542 sbuf_printf(&sb, "%%I"); 3543 break; 3544 } 3545 3546 indexpos = sbuf_len(&sb); 3547 sbuf_printf(&sb, "%u", ncores - 1); 3548 indexlen = sbuf_len(&sb) - indexpos; 3549 break; 3550 case 'N': /* process name */ 3551 sbuf_printf(&sb, "%s", comm); 3552 break; 3553 case 'P': /* process id */ 3554 sbuf_printf(&sb, "%u", pid); 3555 break; 3556 case 'S': /* signal number */ 3557 sbuf_printf(&sb, "%i", signum); 3558 break; 3559 case 'U': /* user id */ 3560 sbuf_printf(&sb, "%u", uid); 3561 break; 3562 default: 3563 log(LOG_ERR, 3564 "Unknown format character %c in " 3565 "corename `%s'\n", format[i], format); 3566 break; 3567 } 3568 break; 3569 default: 3570 sbuf_putc(&sb, format[i]); 3571 break; 3572 } 3573 } 3574 sx_sunlock(&corefilename_lock); 3575 free(hostname, M_TEMP); 3576 if (compress == COMPRESS_GZIP) 3577 sbuf_printf(&sb, GZIP_SUFFIX); 3578 else if (compress == COMPRESS_ZSTD) 3579 sbuf_printf(&sb, ZSTD_SUFFIX); 3580 if (sbuf_error(&sb) != 0) { 3581 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too " 3582 "long\n", (long)pid, comm, (u_long)uid); 3583 sbuf_delete(&sb); 3584 free(name, M_TEMP); 3585 return (ENOMEM); 3586 } 3587 sbuf_finish(&sb); 3588 sbuf_delete(&sb); 3589 3590 if (indexpos != -1) { 3591 error = corefile_open_last(td, name, indexpos, indexlen, ncores, 3592 vpp); 3593 if (error != 0) { 3594 log(LOG_ERR, 3595 "pid %d (%s), uid (%u): Path `%s' failed " 3596 "on initial open test, error = %d\n", 3597 pid, comm, uid, name, error); 3598 } 3599 } else { 3600 cmode = S_IRUSR | S_IWUSR; 3601 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3602 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3603 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3604 if ((td->td_proc->p_flag & P_SUGID) != 0) 3605 flags |= O_EXCL; 3606 3607 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3608 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 3609 NULL); 3610 if (error == 0) { 3611 *vpp = nd.ni_vp; 3612 NDFREE(&nd, NDF_ONLY_PNBUF); 3613 } 3614 } 3615 3616 if (error != 0) { 3617 #ifdef AUDIT 3618 audit_proc_coredump(td, name, error); 3619 #endif 3620 free(name, M_TEMP); 3621 return (error); 3622 } 3623 *namep = name; 3624 return (0); 3625 } 3626 3627 /* 3628 * Dump a process' core. The main routine does some 3629 * policy checking, and creates the name of the coredump; 3630 * then it passes on a vnode and a size limit to the process-specific 3631 * coredump routine if there is one; if there _is not_ one, it returns 3632 * ENOSYS; otherwise it returns the error from the process-specific routine. 3633 */ 3634 3635 static int 3636 coredump(struct thread *td) 3637 { 3638 struct proc *p = td->td_proc; 3639 struct ucred *cred = td->td_ucred; 3640 struct vnode *vp; 3641 struct flock lf; 3642 struct vattr vattr; 3643 size_t fullpathsize; 3644 int error, error1, locked; 3645 char *name; /* name of corefile */ 3646 void *rl_cookie; 3647 off_t limit; 3648 char *fullpath, *freepath = NULL; 3649 struct sbuf *sb; 3650 3651 PROC_LOCK_ASSERT(p, MA_OWNED); 3652 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td); 3653 3654 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) || 3655 (p->p_flag2 & P2_NOTRACE) != 0) { 3656 PROC_UNLOCK(p); 3657 return (EFAULT); 3658 } 3659 3660 /* 3661 * Note that the bulk of limit checking is done after 3662 * the corefile is created. The exception is if the limit 3663 * for corefiles is 0, in which case we don't bother 3664 * creating the corefile at all. This layout means that 3665 * a corefile is truncated instead of not being created, 3666 * if it is larger than the limit. 3667 */ 3668 limit = (off_t)lim_cur(td, RLIMIT_CORE); 3669 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) { 3670 PROC_UNLOCK(p); 3671 return (EFBIG); 3672 } 3673 PROC_UNLOCK(p); 3674 3675 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, 3676 compress_user_cores, p->p_sig, &vp, &name); 3677 if (error != 0) 3678 return (error); 3679 3680 /* 3681 * Don't dump to non-regular files or files with links. 3682 * Do not dump into system files. Effective user must own the corefile. 3683 */ 3684 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 || 3685 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 || 3686 vattr.va_uid != cred->cr_uid) { 3687 VOP_UNLOCK(vp); 3688 error = EFAULT; 3689 goto out; 3690 } 3691 3692 VOP_UNLOCK(vp); 3693 3694 /* Postpone other writers, including core dumps of other processes. */ 3695 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 3696 3697 lf.l_whence = SEEK_SET; 3698 lf.l_start = 0; 3699 lf.l_len = 0; 3700 lf.l_type = F_WRLCK; 3701 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0); 3702 3703 VATTR_NULL(&vattr); 3704 vattr.va_size = 0; 3705 if (set_core_nodump_flag) 3706 vattr.va_flags = UF_NODUMP; 3707 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 3708 VOP_SETATTR(vp, &vattr, cred); 3709 VOP_UNLOCK(vp); 3710 PROC_LOCK(p); 3711 p->p_acflag |= ACORE; 3712 PROC_UNLOCK(p); 3713 3714 if (p->p_sysent->sv_coredump != NULL) { 3715 error = p->p_sysent->sv_coredump(td, vp, limit, 0); 3716 } else { 3717 error = ENOSYS; 3718 } 3719 3720 if (locked) { 3721 lf.l_type = F_UNLCK; 3722 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 3723 } 3724 vn_rangelock_unlock(vp, rl_cookie); 3725 3726 /* 3727 * Notify the userland helper that a process triggered a core dump. 3728 * This allows the helper to run an automated debugging session. 3729 */ 3730 if (error != 0 || coredump_devctl == 0) 3731 goto out; 3732 sb = sbuf_new_auto(); 3733 if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0) 3734 goto out2; 3735 sbuf_printf(sb, "comm=\""); 3736 devctl_safe_quote_sb(sb, fullpath); 3737 free(freepath, M_TEMP); 3738 sbuf_printf(sb, "\" core=\""); 3739 3740 /* 3741 * We can't lookup core file vp directly. When we're replacing a core, and 3742 * other random times, we flush the name cache, so it will fail. Instead, 3743 * if the path of the core is relative, add the current dir in front if it. 3744 */ 3745 if (name[0] != '/') { 3746 fullpathsize = MAXPATHLEN; 3747 freepath = malloc(fullpathsize, M_TEMP, M_WAITOK); 3748 if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) { 3749 free(freepath, M_TEMP); 3750 goto out2; 3751 } 3752 devctl_safe_quote_sb(sb, fullpath); 3753 free(freepath, M_TEMP); 3754 sbuf_putc(sb, '/'); 3755 } 3756 devctl_safe_quote_sb(sb, name); 3757 sbuf_printf(sb, "\""); 3758 if (sbuf_finish(sb) == 0) 3759 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb)); 3760 out2: 3761 sbuf_delete(sb); 3762 out: 3763 error1 = vn_close(vp, FWRITE, cred, td); 3764 if (error == 0) 3765 error = error1; 3766 #ifdef AUDIT 3767 audit_proc_coredump(td, name, error); 3768 #endif 3769 free(name, M_TEMP); 3770 return (error); 3771 } 3772 3773 /* 3774 * Nonexistent system call-- signal process (may want to handle it). Flag 3775 * error in case process won't see signal immediately (blocked or ignored). 3776 */ 3777 #ifndef _SYS_SYSPROTO_H_ 3778 struct nosys_args { 3779 int dummy; 3780 }; 3781 #endif 3782 /* ARGSUSED */ 3783 int 3784 nosys(struct thread *td, struct nosys_args *args) 3785 { 3786 struct proc *p; 3787 3788 p = td->td_proc; 3789 3790 PROC_LOCK(p); 3791 tdsignal(td, SIGSYS); 3792 PROC_UNLOCK(p); 3793 if (kern_lognosys == 1 || kern_lognosys == 3) { 3794 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 3795 td->td_sa.code); 3796 } 3797 if (kern_lognosys == 2 || kern_lognosys == 3 || 3798 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) { 3799 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 3800 td->td_sa.code); 3801 } 3802 return (ENOSYS); 3803 } 3804 3805 /* 3806 * Send a SIGIO or SIGURG signal to a process or process group using stored 3807 * credentials rather than those of the current process. 3808 */ 3809 void 3810 pgsigio(struct sigio **sigiop, int sig, int checkctty) 3811 { 3812 ksiginfo_t ksi; 3813 struct sigio *sigio; 3814 3815 ksiginfo_init(&ksi); 3816 ksi.ksi_signo = sig; 3817 ksi.ksi_code = SI_KERNEL; 3818 3819 SIGIO_LOCK(); 3820 sigio = *sigiop; 3821 if (sigio == NULL) { 3822 SIGIO_UNLOCK(); 3823 return; 3824 } 3825 if (sigio->sio_pgid > 0) { 3826 PROC_LOCK(sigio->sio_proc); 3827 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred)) 3828 kern_psignal(sigio->sio_proc, sig); 3829 PROC_UNLOCK(sigio->sio_proc); 3830 } else if (sigio->sio_pgid < 0) { 3831 struct proc *p; 3832 3833 PGRP_LOCK(sigio->sio_pgrp); 3834 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 3835 PROC_LOCK(p); 3836 if (p->p_state == PRS_NORMAL && 3837 CANSIGIO(sigio->sio_ucred, p->p_ucred) && 3838 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 3839 kern_psignal(p, sig); 3840 PROC_UNLOCK(p); 3841 } 3842 PGRP_UNLOCK(sigio->sio_pgrp); 3843 } 3844 SIGIO_UNLOCK(); 3845 } 3846 3847 static int 3848 filt_sigattach(struct knote *kn) 3849 { 3850 struct proc *p = curproc; 3851 3852 kn->kn_ptr.p_proc = p; 3853 kn->kn_flags |= EV_CLEAR; /* automatically set */ 3854 3855 knlist_add(p->p_klist, kn, 0); 3856 3857 return (0); 3858 } 3859 3860 static void 3861 filt_sigdetach(struct knote *kn) 3862 { 3863 struct proc *p = kn->kn_ptr.p_proc; 3864 3865 knlist_remove(p->p_klist, kn, 0); 3866 } 3867 3868 /* 3869 * signal knotes are shared with proc knotes, so we apply a mask to 3870 * the hint in order to differentiate them from process hints. This 3871 * could be avoided by using a signal-specific knote list, but probably 3872 * isn't worth the trouble. 3873 */ 3874 static int 3875 filt_signal(struct knote *kn, long hint) 3876 { 3877 3878 if (hint & NOTE_SIGNAL) { 3879 hint &= ~NOTE_SIGNAL; 3880 3881 if (kn->kn_id == hint) 3882 kn->kn_data++; 3883 } 3884 return (kn->kn_data != 0); 3885 } 3886 3887 struct sigacts * 3888 sigacts_alloc(void) 3889 { 3890 struct sigacts *ps; 3891 3892 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO); 3893 refcount_init(&ps->ps_refcnt, 1); 3894 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF); 3895 return (ps); 3896 } 3897 3898 void 3899 sigacts_free(struct sigacts *ps) 3900 { 3901 3902 if (refcount_release(&ps->ps_refcnt) == 0) 3903 return; 3904 mtx_destroy(&ps->ps_mtx); 3905 free(ps, M_SUBPROC); 3906 } 3907 3908 struct sigacts * 3909 sigacts_hold(struct sigacts *ps) 3910 { 3911 3912 refcount_acquire(&ps->ps_refcnt); 3913 return (ps); 3914 } 3915 3916 void 3917 sigacts_copy(struct sigacts *dest, struct sigacts *src) 3918 { 3919 3920 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest")); 3921 mtx_lock(&src->ps_mtx); 3922 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt)); 3923 mtx_unlock(&src->ps_mtx); 3924 } 3925 3926 int 3927 sigacts_shared(struct sigacts *ps) 3928 { 3929 3930 return (ps->ps_refcnt > 1); 3931 } 3932 3933 void 3934 sig_drop_caught(struct proc *p) 3935 { 3936 int sig; 3937 struct sigacts *ps; 3938 3939 ps = p->p_sigacts; 3940 PROC_LOCK_ASSERT(p, MA_OWNED); 3941 mtx_assert(&ps->ps_mtx, MA_OWNED); 3942 while (SIGNOTEMPTY(ps->ps_sigcatch)) { 3943 sig = sig_ffs(&ps->ps_sigcatch); 3944 sigdflt(ps, sig); 3945 if ((sigprop(sig) & SIGPROP_IGNORE) != 0) 3946 sigqueue_delete_proc(p, sig); 3947 } 3948 } 3949 3950 static void 3951 sigfastblock_failed(struct thread *td, bool sendsig, bool write) 3952 { 3953 ksiginfo_t ksi; 3954 3955 /* 3956 * Prevent further fetches and SIGSEGVs, allowing thread to 3957 * issue syscalls despite corruption. 3958 */ 3959 sigfastblock_clear(td); 3960 3961 if (!sendsig) 3962 return; 3963 ksiginfo_init_trap(&ksi); 3964 ksi.ksi_signo = SIGSEGV; 3965 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR; 3966 ksi.ksi_addr = td->td_sigblock_ptr; 3967 trapsignal(td, &ksi); 3968 } 3969 3970 static bool 3971 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp) 3972 { 3973 uint32_t res; 3974 3975 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 3976 return (true); 3977 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) { 3978 sigfastblock_failed(td, sendsig, false); 3979 return (false); 3980 } 3981 *valp = res; 3982 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS; 3983 return (true); 3984 } 3985 3986 static void 3987 sigfastblock_resched(struct thread *td, bool resched) 3988 { 3989 struct proc *p; 3990 3991 if (resched) { 3992 p = td->td_proc; 3993 PROC_LOCK(p); 3994 reschedule_signals(p, td->td_sigmask, 0); 3995 PROC_UNLOCK(p); 3996 } 3997 thread_lock(td); 3998 td->td_flags |= TDF_ASTPENDING | TDF_NEEDSIGCHK; 3999 thread_unlock(td); 4000 } 4001 4002 int 4003 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap) 4004 { 4005 struct proc *p; 4006 int error, res; 4007 uint32_t oldval; 4008 4009 error = 0; 4010 p = td->td_proc; 4011 switch (uap->cmd) { 4012 case SIGFASTBLOCK_SETPTR: 4013 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 4014 error = EBUSY; 4015 break; 4016 } 4017 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) { 4018 error = EINVAL; 4019 break; 4020 } 4021 td->td_pflags |= TDP_SIGFASTBLOCK; 4022 td->td_sigblock_ptr = uap->ptr; 4023 break; 4024 4025 case SIGFASTBLOCK_UNBLOCK: 4026 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4027 error = EINVAL; 4028 break; 4029 } 4030 4031 for (;;) { 4032 res = casueword32(td->td_sigblock_ptr, 4033 SIGFASTBLOCK_PEND, &oldval, 0); 4034 if (res == -1) { 4035 error = EFAULT; 4036 sigfastblock_failed(td, false, true); 4037 break; 4038 } 4039 if (res == 0) 4040 break; 4041 MPASS(res == 1); 4042 if (oldval != SIGFASTBLOCK_PEND) { 4043 error = EBUSY; 4044 break; 4045 } 4046 error = thread_check_susp(td, false); 4047 if (error != 0) 4048 break; 4049 } 4050 if (error != 0) 4051 break; 4052 4053 /* 4054 * td_sigblock_val is cleared there, but not on a 4055 * syscall exit. The end effect is that a single 4056 * interruptible sleep, while user sigblock word is 4057 * set, might return EINTR or ERESTART to usermode 4058 * without delivering signal. All further sleeps, 4059 * until userspace clears the word and does 4060 * sigfastblock(UNBLOCK), observe current word and no 4061 * longer get interrupted. It is slight 4062 * non-conformance, with alternative to have read the 4063 * sigblock word on each syscall entry. 4064 */ 4065 td->td_sigblock_val = 0; 4066 4067 /* 4068 * Rely on normal ast mechanism to deliver pending 4069 * signals to current thread. But notify others about 4070 * fake unblock. 4071 */ 4072 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1); 4073 4074 break; 4075 4076 case SIGFASTBLOCK_UNSETPTR: 4077 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4078 error = EINVAL; 4079 break; 4080 } 4081 if (!sigfastblock_fetch_sig(td, false, &oldval)) { 4082 error = EFAULT; 4083 break; 4084 } 4085 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) { 4086 error = EBUSY; 4087 break; 4088 } 4089 sigfastblock_clear(td); 4090 break; 4091 4092 default: 4093 error = EINVAL; 4094 break; 4095 } 4096 return (error); 4097 } 4098 4099 void 4100 sigfastblock_clear(struct thread *td) 4101 { 4102 bool resched; 4103 4104 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4105 return; 4106 td->td_sigblock_val = 0; 4107 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 || 4108 SIGPENDING(td); 4109 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING); 4110 sigfastblock_resched(td, resched); 4111 } 4112 4113 void 4114 sigfastblock_fetch(struct thread *td) 4115 { 4116 uint32_t val; 4117 4118 (void)sigfastblock_fetch_sig(td, true, &val); 4119 } 4120 4121 static void 4122 sigfastblock_setpend1(struct thread *td) 4123 { 4124 int res; 4125 uint32_t oldval; 4126 4127 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4128 return; 4129 res = fueword32((void *)td->td_sigblock_ptr, &oldval); 4130 if (res == -1) { 4131 sigfastblock_failed(td, true, false); 4132 return; 4133 } 4134 for (;;) { 4135 res = casueword32(td->td_sigblock_ptr, oldval, &oldval, 4136 oldval | SIGFASTBLOCK_PEND); 4137 if (res == -1) { 4138 sigfastblock_failed(td, true, true); 4139 return; 4140 } 4141 if (res == 0) { 4142 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS; 4143 td->td_pflags &= ~TDP_SIGFASTPENDING; 4144 break; 4145 } 4146 MPASS(res == 1); 4147 if (thread_check_susp(td, false) != 0) 4148 break; 4149 } 4150 } 4151 4152 void 4153 sigfastblock_setpend(struct thread *td, bool resched) 4154 { 4155 struct proc *p; 4156 4157 sigfastblock_setpend1(td); 4158 if (resched) { 4159 p = td->td_proc; 4160 PROC_LOCK(p); 4161 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK); 4162 PROC_UNLOCK(p); 4163 } 4164 } 4165