Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_sig.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD: releng/11.1/sys/kern/kern_sig.c 318845 2017-05-25 01:09:45Z markj $"); 39 40 #include "opt_compat.h" 41 #include "opt_gzio.h" 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/bus.h> 51 #include <sys/capsicum.h> 52 #include <sys/condvar.h> 53 #include <sys/event.h> 54 #include <sys/fcntl.h> 55 #include <sys/imgact.h> 56 #include <sys/kernel.h> 57 #include <sys/ktr.h> 58 #include <sys/ktrace.h> 59 #include <sys/lock.h> 60 #include <sys/malloc.h> 61 #include <sys/mutex.h> 62 #include <sys/refcount.h> 63 #include <sys/namei.h> 64 #include <sys/proc.h> 65 #include <sys/procdesc.h> 66 #include <sys/posix4.h> 67 #include <sys/pioctl.h> 68 #include <sys/racct.h> 69 #include <sys/resourcevar.h> 70 #include <sys/sdt.h> 71 #include <sys/sbuf.h> 72 #include <sys/sleepqueue.h> 73 #include <sys/smp.h> 74 #include <sys/stat.h> 75 #include <sys/sx.h> 76 #include <sys/syscallsubr.h> 77 #include <sys/sysctl.h> 78 #include <sys/sysent.h> 79 #include <sys/syslog.h> 80 #include <sys/sysproto.h> 81 #include <sys/timers.h> 82 #include <sys/unistd.h> 83 #include <sys/wait.h> 84 #include <vm/vm.h> 85 #include <vm/vm_extern.h> 86 #include <vm/uma.h> 87 88 #include <sys/jail.h> 89 90 #include <machine/cpu.h> 91 92 #include <security/audit/audit.h> 93 94 #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */ 95 96 SDT_PROVIDER_DECLARE(proc); 97 SDT_PROBE_DEFINE3(proc, , , signal__send, 98 "struct thread *", "struct proc *", "int"); 99 SDT_PROBE_DEFINE2(proc, , , signal__clear, 100 "int", "ksiginfo_t *"); 101 SDT_PROBE_DEFINE3(proc, , , signal__discard, 102 "struct thread *", "struct proc *", "int"); 103 104 static int coredump(struct thread *); 105 static int killpg1(struct thread *td, int sig, int pgid, int all, 106 ksiginfo_t *ksi); 107 static int issignal(struct thread *td); 108 static int sigprop(int sig); 109 static void tdsigwakeup(struct thread *, int, sig_t, int); 110 static int sig_suspend_threads(struct thread *, struct proc *, int); 111 static int filt_sigattach(struct knote *kn); 112 static void filt_sigdetach(struct knote *kn); 113 static int filt_signal(struct knote *kn, long hint); 114 static struct thread *sigtd(struct proc *p, int sig, int prop); 115 static void sigqueue_start(void); 116 117 static uma_zone_t ksiginfo_zone = NULL; 118 struct filterops sig_filtops = { 119 .f_isfd = 0, 120 .f_attach = filt_sigattach, 121 .f_detach = filt_sigdetach, 122 .f_event = filt_signal, 123 }; 124 125 static int kern_logsigexit = 1; 126 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 127 &kern_logsigexit, 0, 128 "Log processes quitting on abnormal signals to syslog(3)"); 129 130 static int kern_forcesigexit = 1; 131 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW, 132 &kern_forcesigexit, 0, "Force trap signal to be handled"); 133 134 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0, 135 "POSIX real time signal"); 136 137 static int max_pending_per_proc = 128; 138 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW, 139 &max_pending_per_proc, 0, "Max pending signals per proc"); 140 141 static int preallocate_siginfo = 1024; 142 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN, 143 &preallocate_siginfo, 0, "Preallocated signal memory size"); 144 145 static int signal_overflow = 0; 146 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD, 147 &signal_overflow, 0, "Number of signals overflew"); 148 149 static int signal_alloc_fail = 0; 150 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD, 151 &signal_alloc_fail, 0, "signals failed to be allocated"); 152 153 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL); 154 155 /* 156 * Policy -- Can ucred cr1 send SIGIO to process cr2? 157 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG 158 * in the right situations. 159 */ 160 #define CANSIGIO(cr1, cr2) \ 161 ((cr1)->cr_uid == 0 || \ 162 (cr1)->cr_ruid == (cr2)->cr_ruid || \ 163 (cr1)->cr_uid == (cr2)->cr_ruid || \ 164 (cr1)->cr_ruid == (cr2)->cr_uid || \ 165 (cr1)->cr_uid == (cr2)->cr_uid) 166 167 static int sugid_coredump; 168 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN, 169 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core"); 170 171 static int capmode_coredump; 172 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN, 173 &capmode_coredump, 0, "Allow processes in capability mode to dump core"); 174 175 static int do_coredump = 1; 176 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 177 &do_coredump, 0, "Enable/Disable coredumps"); 178 179 static int set_core_nodump_flag = 0; 180 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag, 181 0, "Enable setting the NODUMP flag on coredump files"); 182 183 static int coredump_devctl = 0; 184 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl, 185 0, "Generate a devctl notification when processes coredump"); 186 187 /* 188 * Signal properties and actions. 189 * The array below categorizes the signals and their default actions 190 * according to the following properties: 191 */ 192 #define SA_KILL 0x01 /* terminates process by default */ 193 #define SA_CORE 0x02 /* ditto and coredumps */ 194 #define SA_STOP 0x04 /* suspend process */ 195 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 196 #define SA_IGNORE 0x10 /* ignore by default */ 197 #define SA_CONT 0x20 /* continue if suspended */ 198 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 199 200 static int sigproptbl[NSIG] = { 201 SA_KILL, /* SIGHUP */ 202 SA_KILL, /* SIGINT */ 203 SA_KILL|SA_CORE, /* SIGQUIT */ 204 SA_KILL|SA_CORE, /* SIGILL */ 205 SA_KILL|SA_CORE, /* SIGTRAP */ 206 SA_KILL|SA_CORE, /* SIGABRT */ 207 SA_KILL|SA_CORE, /* SIGEMT */ 208 SA_KILL|SA_CORE, /* SIGFPE */ 209 SA_KILL, /* SIGKILL */ 210 SA_KILL|SA_CORE, /* SIGBUS */ 211 SA_KILL|SA_CORE, /* SIGSEGV */ 212 SA_KILL|SA_CORE, /* SIGSYS */ 213 SA_KILL, /* SIGPIPE */ 214 SA_KILL, /* SIGALRM */ 215 SA_KILL, /* SIGTERM */ 216 SA_IGNORE, /* SIGURG */ 217 SA_STOP, /* SIGSTOP */ 218 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 219 SA_IGNORE|SA_CONT, /* SIGCONT */ 220 SA_IGNORE, /* SIGCHLD */ 221 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 222 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 223 SA_IGNORE, /* SIGIO */ 224 SA_KILL, /* SIGXCPU */ 225 SA_KILL, /* SIGXFSZ */ 226 SA_KILL, /* SIGVTALRM */ 227 SA_KILL, /* SIGPROF */ 228 SA_IGNORE, /* SIGWINCH */ 229 SA_IGNORE, /* SIGINFO */ 230 SA_KILL, /* SIGUSR1 */ 231 SA_KILL, /* SIGUSR2 */ 232 }; 233 234 static void reschedule_signals(struct proc *p, sigset_t block, int flags); 235 236 static void 237 sigqueue_start(void) 238 { 239 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t), 240 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 241 uma_prealloc(ksiginfo_zone, preallocate_siginfo); 242 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS); 243 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1); 244 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc); 245 } 246 247 ksiginfo_t * 248 ksiginfo_alloc(int wait) 249 { 250 int flags; 251 252 flags = M_ZERO; 253 if (! wait) 254 flags |= M_NOWAIT; 255 if (ksiginfo_zone != NULL) 256 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags)); 257 return (NULL); 258 } 259 260 void 261 ksiginfo_free(ksiginfo_t *ksi) 262 { 263 uma_zfree(ksiginfo_zone, ksi); 264 } 265 266 static __inline int 267 ksiginfo_tryfree(ksiginfo_t *ksi) 268 { 269 if (!(ksi->ksi_flags & KSI_EXT)) { 270 uma_zfree(ksiginfo_zone, ksi); 271 return (1); 272 } 273 return (0); 274 } 275 276 void 277 sigqueue_init(sigqueue_t *list, struct proc *p) 278 { 279 SIGEMPTYSET(list->sq_signals); 280 SIGEMPTYSET(list->sq_kill); 281 SIGEMPTYSET(list->sq_ptrace); 282 TAILQ_INIT(&list->sq_list); 283 list->sq_proc = p; 284 list->sq_flags = SQ_INIT; 285 } 286 287 /* 288 * Get a signal's ksiginfo. 289 * Return: 290 * 0 - signal not found 291 * others - signal number 292 */ 293 static int 294 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si) 295 { 296 struct proc *p = sq->sq_proc; 297 struct ksiginfo *ksi, *next; 298 int count = 0; 299 300 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 301 302 if (!SIGISMEMBER(sq->sq_signals, signo)) 303 return (0); 304 305 if (SIGISMEMBER(sq->sq_ptrace, signo)) { 306 count++; 307 SIGDELSET(sq->sq_ptrace, signo); 308 si->ksi_flags |= KSI_PTRACE; 309 } 310 if (SIGISMEMBER(sq->sq_kill, signo)) { 311 count++; 312 if (count == 1) 313 SIGDELSET(sq->sq_kill, signo); 314 } 315 316 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 317 if (ksi->ksi_signo == signo) { 318 if (count == 0) { 319 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 320 ksi->ksi_sigq = NULL; 321 ksiginfo_copy(ksi, si); 322 if (ksiginfo_tryfree(ksi) && p != NULL) 323 p->p_pendingcnt--; 324 } 325 if (++count > 1) 326 break; 327 } 328 } 329 330 if (count <= 1) 331 SIGDELSET(sq->sq_signals, signo); 332 si->ksi_signo = signo; 333 return (signo); 334 } 335 336 void 337 sigqueue_take(ksiginfo_t *ksi) 338 { 339 struct ksiginfo *kp; 340 struct proc *p; 341 sigqueue_t *sq; 342 343 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL) 344 return; 345 346 p = sq->sq_proc; 347 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 348 ksi->ksi_sigq = NULL; 349 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL) 350 p->p_pendingcnt--; 351 352 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL; 353 kp = TAILQ_NEXT(kp, ksi_link)) { 354 if (kp->ksi_signo == ksi->ksi_signo) 355 break; 356 } 357 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) && 358 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo)) 359 SIGDELSET(sq->sq_signals, ksi->ksi_signo); 360 } 361 362 static int 363 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si) 364 { 365 struct proc *p = sq->sq_proc; 366 struct ksiginfo *ksi; 367 int ret = 0; 368 369 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 370 371 /* 372 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path 373 * for these signals. 374 */ 375 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) { 376 SIGADDSET(sq->sq_kill, signo); 377 goto out_set_bit; 378 } 379 380 /* directly insert the ksi, don't copy it */ 381 if (si->ksi_flags & KSI_INS) { 382 if (si->ksi_flags & KSI_HEAD) 383 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link); 384 else 385 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link); 386 si->ksi_sigq = sq; 387 goto out_set_bit; 388 } 389 390 if (__predict_false(ksiginfo_zone == NULL)) { 391 SIGADDSET(sq->sq_kill, signo); 392 goto out_set_bit; 393 } 394 395 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) { 396 signal_overflow++; 397 ret = EAGAIN; 398 } else if ((ksi = ksiginfo_alloc(0)) == NULL) { 399 signal_alloc_fail++; 400 ret = EAGAIN; 401 } else { 402 if (p != NULL) 403 p->p_pendingcnt++; 404 ksiginfo_copy(si, ksi); 405 ksi->ksi_signo = signo; 406 if (si->ksi_flags & KSI_HEAD) 407 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link); 408 else 409 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link); 410 ksi->ksi_sigq = sq; 411 } 412 413 if (ret != 0) { 414 if ((si->ksi_flags & KSI_PTRACE) != 0) { 415 SIGADDSET(sq->sq_ptrace, signo); 416 ret = 0; 417 goto out_set_bit; 418 } else if ((si->ksi_flags & KSI_TRAP) != 0 || 419 (si->ksi_flags & KSI_SIGQ) == 0) { 420 SIGADDSET(sq->sq_kill, signo); 421 ret = 0; 422 goto out_set_bit; 423 } 424 return (ret); 425 } 426 427 out_set_bit: 428 SIGADDSET(sq->sq_signals, signo); 429 return (ret); 430 } 431 432 void 433 sigqueue_flush(sigqueue_t *sq) 434 { 435 struct proc *p = sq->sq_proc; 436 ksiginfo_t *ksi; 437 438 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 439 440 if (p != NULL) 441 PROC_LOCK_ASSERT(p, MA_OWNED); 442 443 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) { 444 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 445 ksi->ksi_sigq = NULL; 446 if (ksiginfo_tryfree(ksi) && p != NULL) 447 p->p_pendingcnt--; 448 } 449 450 SIGEMPTYSET(sq->sq_signals); 451 SIGEMPTYSET(sq->sq_kill); 452 SIGEMPTYSET(sq->sq_ptrace); 453 } 454 455 static void 456 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set) 457 { 458 sigset_t tmp; 459 struct proc *p1, *p2; 460 ksiginfo_t *ksi, *next; 461 462 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited")); 463 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited")); 464 p1 = src->sq_proc; 465 p2 = dst->sq_proc; 466 /* Move siginfo to target list */ 467 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) { 468 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 469 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link); 470 if (p1 != NULL) 471 p1->p_pendingcnt--; 472 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link); 473 ksi->ksi_sigq = dst; 474 if (p2 != NULL) 475 p2->p_pendingcnt++; 476 } 477 } 478 479 /* Move pending bits to target list */ 480 tmp = src->sq_kill; 481 SIGSETAND(tmp, *set); 482 SIGSETOR(dst->sq_kill, tmp); 483 SIGSETNAND(src->sq_kill, tmp); 484 485 tmp = src->sq_ptrace; 486 SIGSETAND(tmp, *set); 487 SIGSETOR(dst->sq_ptrace, tmp); 488 SIGSETNAND(src->sq_ptrace, tmp); 489 490 tmp = src->sq_signals; 491 SIGSETAND(tmp, *set); 492 SIGSETOR(dst->sq_signals, tmp); 493 SIGSETNAND(src->sq_signals, tmp); 494 } 495 496 #if 0 497 static void 498 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo) 499 { 500 sigset_t set; 501 502 SIGEMPTYSET(set); 503 SIGADDSET(set, signo); 504 sigqueue_move_set(src, dst, &set); 505 } 506 #endif 507 508 static void 509 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set) 510 { 511 struct proc *p = sq->sq_proc; 512 ksiginfo_t *ksi, *next; 513 514 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited")); 515 516 /* Remove siginfo queue */ 517 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 518 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 519 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 520 ksi->ksi_sigq = NULL; 521 if (ksiginfo_tryfree(ksi) && p != NULL) 522 p->p_pendingcnt--; 523 } 524 } 525 SIGSETNAND(sq->sq_kill, *set); 526 SIGSETNAND(sq->sq_ptrace, *set); 527 SIGSETNAND(sq->sq_signals, *set); 528 } 529 530 void 531 sigqueue_delete(sigqueue_t *sq, int signo) 532 { 533 sigset_t set; 534 535 SIGEMPTYSET(set); 536 SIGADDSET(set, signo); 537 sigqueue_delete_set(sq, &set); 538 } 539 540 /* Remove a set of signals for a process */ 541 static void 542 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set) 543 { 544 sigqueue_t worklist; 545 struct thread *td0; 546 547 PROC_LOCK_ASSERT(p, MA_OWNED); 548 549 sigqueue_init(&worklist, NULL); 550 sigqueue_move_set(&p->p_sigqueue, &worklist, set); 551 552 FOREACH_THREAD_IN_PROC(p, td0) 553 sigqueue_move_set(&td0->td_sigqueue, &worklist, set); 554 555 sigqueue_flush(&worklist); 556 } 557 558 void 559 sigqueue_delete_proc(struct proc *p, int signo) 560 { 561 sigset_t set; 562 563 SIGEMPTYSET(set); 564 SIGADDSET(set, signo); 565 sigqueue_delete_set_proc(p, &set); 566 } 567 568 static void 569 sigqueue_delete_stopmask_proc(struct proc *p) 570 { 571 sigset_t set; 572 573 SIGEMPTYSET(set); 574 SIGADDSET(set, SIGSTOP); 575 SIGADDSET(set, SIGTSTP); 576 SIGADDSET(set, SIGTTIN); 577 SIGADDSET(set, SIGTTOU); 578 sigqueue_delete_set_proc(p, &set); 579 } 580 581 /* 582 * Determine signal that should be delivered to thread td, the current 583 * thread, 0 if none. If there is a pending stop signal with default 584 * action, the process stops in issignal(). 585 */ 586 int 587 cursig(struct thread *td) 588 { 589 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 590 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED); 591 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 592 return (SIGPENDING(td) ? issignal(td) : 0); 593 } 594 595 /* 596 * Arrange for ast() to handle unmasked pending signals on return to user 597 * mode. This must be called whenever a signal is added to td_sigqueue or 598 * unmasked in td_sigmask. 599 */ 600 void 601 signotify(struct thread *td) 602 { 603 struct proc *p; 604 605 p = td->td_proc; 606 607 PROC_LOCK_ASSERT(p, MA_OWNED); 608 609 if (SIGPENDING(td)) { 610 thread_lock(td); 611 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING; 612 thread_unlock(td); 613 } 614 } 615 616 int 617 sigonstack(size_t sp) 618 { 619 struct thread *td = curthread; 620 621 return ((td->td_pflags & TDP_ALTSTACK) ? 622 #if defined(COMPAT_43) 623 ((td->td_sigstk.ss_size == 0) ? 624 (td->td_sigstk.ss_flags & SS_ONSTACK) : 625 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)) 626 #else 627 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size) 628 #endif 629 : 0); 630 } 631 632 static __inline int 633 sigprop(int sig) 634 { 635 636 if (sig > 0 && sig < NSIG) 637 return (sigproptbl[_SIG_IDX(sig)]); 638 return (0); 639 } 640 641 int 642 sig_ffs(sigset_t *set) 643 { 644 int i; 645 646 for (i = 0; i < _SIG_WORDS; i++) 647 if (set->__bits[i]) 648 return (ffs(set->__bits[i]) + (i * 32)); 649 return (0); 650 } 651 652 static bool 653 sigact_flag_test(const struct sigaction *act, int flag) 654 { 655 656 /* 657 * SA_SIGINFO is reset when signal disposition is set to 658 * ignore or default. Other flags are kept according to user 659 * settings. 660 */ 661 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO || 662 ((__sighandler_t *)act->sa_sigaction != SIG_IGN && 663 (__sighandler_t *)act->sa_sigaction != SIG_DFL))); 664 } 665 666 /* 667 * kern_sigaction 668 * sigaction 669 * freebsd4_sigaction 670 * osigaction 671 */ 672 int 673 kern_sigaction(struct thread *td, int sig, const struct sigaction *act, 674 struct sigaction *oact, int flags) 675 { 676 struct sigacts *ps; 677 struct proc *p = td->td_proc; 678 679 if (!_SIG_VALID(sig)) 680 return (EINVAL); 681 if (act != NULL && act->sa_handler != SIG_DFL && 682 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK | 683 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | 684 SA_NOCLDWAIT | SA_SIGINFO)) != 0) 685 return (EINVAL); 686 687 PROC_LOCK(p); 688 ps = p->p_sigacts; 689 mtx_lock(&ps->ps_mtx); 690 if (oact) { 691 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 692 oact->sa_flags = 0; 693 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 694 oact->sa_flags |= SA_ONSTACK; 695 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 696 oact->sa_flags |= SA_RESTART; 697 if (SIGISMEMBER(ps->ps_sigreset, sig)) 698 oact->sa_flags |= SA_RESETHAND; 699 if (SIGISMEMBER(ps->ps_signodefer, sig)) 700 oact->sa_flags |= SA_NODEFER; 701 if (SIGISMEMBER(ps->ps_siginfo, sig)) { 702 oact->sa_flags |= SA_SIGINFO; 703 oact->sa_sigaction = 704 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)]; 705 } else 706 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 707 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP) 708 oact->sa_flags |= SA_NOCLDSTOP; 709 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT) 710 oact->sa_flags |= SA_NOCLDWAIT; 711 } 712 if (act) { 713 if ((sig == SIGKILL || sig == SIGSTOP) && 714 act->sa_handler != SIG_DFL) { 715 mtx_unlock(&ps->ps_mtx); 716 PROC_UNLOCK(p); 717 return (EINVAL); 718 } 719 720 /* 721 * Change setting atomically. 722 */ 723 724 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 725 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 726 if (sigact_flag_test(act, SA_SIGINFO)) { 727 ps->ps_sigact[_SIG_IDX(sig)] = 728 (__sighandler_t *)act->sa_sigaction; 729 SIGADDSET(ps->ps_siginfo, sig); 730 } else { 731 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 732 SIGDELSET(ps->ps_siginfo, sig); 733 } 734 if (!sigact_flag_test(act, SA_RESTART)) 735 SIGADDSET(ps->ps_sigintr, sig); 736 else 737 SIGDELSET(ps->ps_sigintr, sig); 738 if (sigact_flag_test(act, SA_ONSTACK)) 739 SIGADDSET(ps->ps_sigonstack, sig); 740 else 741 SIGDELSET(ps->ps_sigonstack, sig); 742 if (sigact_flag_test(act, SA_RESETHAND)) 743 SIGADDSET(ps->ps_sigreset, sig); 744 else 745 SIGDELSET(ps->ps_sigreset, sig); 746 if (sigact_flag_test(act, SA_NODEFER)) 747 SIGADDSET(ps->ps_signodefer, sig); 748 else 749 SIGDELSET(ps->ps_signodefer, sig); 750 if (sig == SIGCHLD) { 751 if (act->sa_flags & SA_NOCLDSTOP) 752 ps->ps_flag |= PS_NOCLDSTOP; 753 else 754 ps->ps_flag &= ~PS_NOCLDSTOP; 755 if (act->sa_flags & SA_NOCLDWAIT) { 756 /* 757 * Paranoia: since SA_NOCLDWAIT is implemented 758 * by reparenting the dying child to PID 1 (and 759 * trust it to reap the zombie), PID 1 itself 760 * is forbidden to set SA_NOCLDWAIT. 761 */ 762 if (p->p_pid == 1) 763 ps->ps_flag &= ~PS_NOCLDWAIT; 764 else 765 ps->ps_flag |= PS_NOCLDWAIT; 766 } else 767 ps->ps_flag &= ~PS_NOCLDWAIT; 768 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 769 ps->ps_flag |= PS_CLDSIGIGN; 770 else 771 ps->ps_flag &= ~PS_CLDSIGIGN; 772 } 773 /* 774 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 775 * and for signals set to SIG_DFL where the default is to 776 * ignore. However, don't put SIGCONT in ps_sigignore, as we 777 * have to restart the process. 778 */ 779 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 780 (sigprop(sig) & SA_IGNORE && 781 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 782 /* never to be seen again */ 783 sigqueue_delete_proc(p, sig); 784 if (sig != SIGCONT) 785 /* easier in psignal */ 786 SIGADDSET(ps->ps_sigignore, sig); 787 SIGDELSET(ps->ps_sigcatch, sig); 788 } else { 789 SIGDELSET(ps->ps_sigignore, sig); 790 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 791 SIGDELSET(ps->ps_sigcatch, sig); 792 else 793 SIGADDSET(ps->ps_sigcatch, sig); 794 } 795 #ifdef COMPAT_FREEBSD4 796 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 797 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 798 (flags & KSA_FREEBSD4) == 0) 799 SIGDELSET(ps->ps_freebsd4, sig); 800 else 801 SIGADDSET(ps->ps_freebsd4, sig); 802 #endif 803 #ifdef COMPAT_43 804 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 805 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 806 (flags & KSA_OSIGSET) == 0) 807 SIGDELSET(ps->ps_osigset, sig); 808 else 809 SIGADDSET(ps->ps_osigset, sig); 810 #endif 811 } 812 mtx_unlock(&ps->ps_mtx); 813 PROC_UNLOCK(p); 814 return (0); 815 } 816 817 #ifndef _SYS_SYSPROTO_H_ 818 struct sigaction_args { 819 int sig; 820 struct sigaction *act; 821 struct sigaction *oact; 822 }; 823 #endif 824 int 825 sys_sigaction(td, uap) 826 struct thread *td; 827 register struct sigaction_args *uap; 828 { 829 struct sigaction act, oact; 830 register struct sigaction *actp, *oactp; 831 int error; 832 833 actp = (uap->act != NULL) ? &act : NULL; 834 oactp = (uap->oact != NULL) ? &oact : NULL; 835 if (actp) { 836 error = copyin(uap->act, actp, sizeof(act)); 837 if (error) 838 return (error); 839 } 840 error = kern_sigaction(td, uap->sig, actp, oactp, 0); 841 if (oactp && !error) 842 error = copyout(oactp, uap->oact, sizeof(oact)); 843 return (error); 844 } 845 846 #ifdef COMPAT_FREEBSD4 847 #ifndef _SYS_SYSPROTO_H_ 848 struct freebsd4_sigaction_args { 849 int sig; 850 struct sigaction *act; 851 struct sigaction *oact; 852 }; 853 #endif 854 int 855 freebsd4_sigaction(td, uap) 856 struct thread *td; 857 register struct freebsd4_sigaction_args *uap; 858 { 859 struct sigaction act, oact; 860 register struct sigaction *actp, *oactp; 861 int error; 862 863 864 actp = (uap->act != NULL) ? &act : NULL; 865 oactp = (uap->oact != NULL) ? &oact : NULL; 866 if (actp) { 867 error = copyin(uap->act, actp, sizeof(act)); 868 if (error) 869 return (error); 870 } 871 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4); 872 if (oactp && !error) 873 error = copyout(oactp, uap->oact, sizeof(oact)); 874 return (error); 875 } 876 #endif /* COMAPT_FREEBSD4 */ 877 878 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 879 #ifndef _SYS_SYSPROTO_H_ 880 struct osigaction_args { 881 int signum; 882 struct osigaction *nsa; 883 struct osigaction *osa; 884 }; 885 #endif 886 int 887 osigaction(td, uap) 888 struct thread *td; 889 register struct osigaction_args *uap; 890 { 891 struct osigaction sa; 892 struct sigaction nsa, osa; 893 register struct sigaction *nsap, *osap; 894 int error; 895 896 if (uap->signum <= 0 || uap->signum >= ONSIG) 897 return (EINVAL); 898 899 nsap = (uap->nsa != NULL) ? &nsa : NULL; 900 osap = (uap->osa != NULL) ? &osa : NULL; 901 902 if (nsap) { 903 error = copyin(uap->nsa, &sa, sizeof(sa)); 904 if (error) 905 return (error); 906 nsap->sa_handler = sa.sa_handler; 907 nsap->sa_flags = sa.sa_flags; 908 OSIG2SIG(sa.sa_mask, nsap->sa_mask); 909 } 910 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 911 if (osap && !error) { 912 sa.sa_handler = osap->sa_handler; 913 sa.sa_flags = osap->sa_flags; 914 SIG2OSIG(osap->sa_mask, sa.sa_mask); 915 error = copyout(&sa, uap->osa, sizeof(sa)); 916 } 917 return (error); 918 } 919 920 #if !defined(__i386__) 921 /* Avoid replicating the same stub everywhere */ 922 int 923 osigreturn(td, uap) 924 struct thread *td; 925 struct osigreturn_args *uap; 926 { 927 928 return (nosys(td, (struct nosys_args *)uap)); 929 } 930 #endif 931 #endif /* COMPAT_43 */ 932 933 /* 934 * Initialize signal state for process 0; 935 * set to ignore signals that are ignored by default. 936 */ 937 void 938 siginit(p) 939 struct proc *p; 940 { 941 register int i; 942 struct sigacts *ps; 943 944 PROC_LOCK(p); 945 ps = p->p_sigacts; 946 mtx_lock(&ps->ps_mtx); 947 for (i = 1; i <= NSIG; i++) { 948 if (sigprop(i) & SA_IGNORE && i != SIGCONT) { 949 SIGADDSET(ps->ps_sigignore, i); 950 } 951 } 952 mtx_unlock(&ps->ps_mtx); 953 PROC_UNLOCK(p); 954 } 955 956 /* 957 * Reset specified signal to the default disposition. 958 */ 959 static void 960 sigdflt(struct sigacts *ps, int sig) 961 { 962 963 mtx_assert(&ps->ps_mtx, MA_OWNED); 964 SIGDELSET(ps->ps_sigcatch, sig); 965 if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT) 966 SIGADDSET(ps->ps_sigignore, sig); 967 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 968 SIGDELSET(ps->ps_siginfo, sig); 969 } 970 971 /* 972 * Reset signals for an exec of the specified process. 973 */ 974 void 975 execsigs(struct proc *p) 976 { 977 sigset_t osigignore; 978 struct sigacts *ps; 979 int sig; 980 struct thread *td; 981 982 /* 983 * Reset caught signals. Held signals remain held 984 * through td_sigmask (unless they were caught, 985 * and are now ignored by default). 986 */ 987 PROC_LOCK_ASSERT(p, MA_OWNED); 988 ps = p->p_sigacts; 989 mtx_lock(&ps->ps_mtx); 990 while (SIGNOTEMPTY(ps->ps_sigcatch)) { 991 sig = sig_ffs(&ps->ps_sigcatch); 992 sigdflt(ps, sig); 993 if ((sigprop(sig) & SA_IGNORE) != 0) 994 sigqueue_delete_proc(p, sig); 995 } 996 997 /* 998 * As CloudABI processes cannot modify signal handlers, fully 999 * reset all signals to their default behavior. Do ignore 1000 * SIGPIPE, as it would otherwise be impossible to recover from 1001 * writes to broken pipes and sockets. 1002 */ 1003 if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) { 1004 osigignore = ps->ps_sigignore; 1005 while (SIGNOTEMPTY(osigignore)) { 1006 sig = sig_ffs(&osigignore); 1007 SIGDELSET(osigignore, sig); 1008 if (sig != SIGPIPE) 1009 sigdflt(ps, sig); 1010 } 1011 SIGADDSET(ps->ps_sigignore, SIGPIPE); 1012 } 1013 1014 /* 1015 * Reset stack state to the user stack. 1016 * Clear set of signals caught on the signal stack. 1017 */ 1018 td = curthread; 1019 MPASS(td->td_proc == p); 1020 td->td_sigstk.ss_flags = SS_DISABLE; 1021 td->td_sigstk.ss_size = 0; 1022 td->td_sigstk.ss_sp = 0; 1023 td->td_pflags &= ~TDP_ALTSTACK; 1024 /* 1025 * Reset no zombies if child dies flag as Solaris does. 1026 */ 1027 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 1028 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 1029 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 1030 mtx_unlock(&ps->ps_mtx); 1031 } 1032 1033 /* 1034 * kern_sigprocmask() 1035 * 1036 * Manipulate signal mask. 1037 */ 1038 int 1039 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset, 1040 int flags) 1041 { 1042 sigset_t new_block, oset1; 1043 struct proc *p; 1044 int error; 1045 1046 p = td->td_proc; 1047 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0) 1048 PROC_LOCK_ASSERT(p, MA_OWNED); 1049 else 1050 PROC_LOCK(p); 1051 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 1052 ? MA_OWNED : MA_NOTOWNED); 1053 if (oset != NULL) 1054 *oset = td->td_sigmask; 1055 1056 error = 0; 1057 if (set != NULL) { 1058 switch (how) { 1059 case SIG_BLOCK: 1060 SIG_CANTMASK(*set); 1061 oset1 = td->td_sigmask; 1062 SIGSETOR(td->td_sigmask, *set); 1063 new_block = td->td_sigmask; 1064 SIGSETNAND(new_block, oset1); 1065 break; 1066 case SIG_UNBLOCK: 1067 SIGSETNAND(td->td_sigmask, *set); 1068 signotify(td); 1069 goto out; 1070 case SIG_SETMASK: 1071 SIG_CANTMASK(*set); 1072 oset1 = td->td_sigmask; 1073 if (flags & SIGPROCMASK_OLD) 1074 SIGSETLO(td->td_sigmask, *set); 1075 else 1076 td->td_sigmask = *set; 1077 new_block = td->td_sigmask; 1078 SIGSETNAND(new_block, oset1); 1079 signotify(td); 1080 break; 1081 default: 1082 error = EINVAL; 1083 goto out; 1084 } 1085 1086 /* 1087 * The new_block set contains signals that were not previously 1088 * blocked, but are blocked now. 1089 * 1090 * In case we block any signal that was not previously blocked 1091 * for td, and process has the signal pending, try to schedule 1092 * signal delivery to some thread that does not block the 1093 * signal, possibly waking it up. 1094 */ 1095 if (p->p_numthreads != 1) 1096 reschedule_signals(p, new_block, flags); 1097 } 1098 1099 out: 1100 if (!(flags & SIGPROCMASK_PROC_LOCKED)) 1101 PROC_UNLOCK(p); 1102 return (error); 1103 } 1104 1105 #ifndef _SYS_SYSPROTO_H_ 1106 struct sigprocmask_args { 1107 int how; 1108 const sigset_t *set; 1109 sigset_t *oset; 1110 }; 1111 #endif 1112 int 1113 sys_sigprocmask(td, uap) 1114 register struct thread *td; 1115 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(td, uap) 1144 register struct thread *td; 1145 struct osigprocmask_args *uap; 1146 { 1147 sigset_t set, oset; 1148 int error; 1149 1150 OSIG2SIG(uap->mask, set); 1151 error = kern_sigprocmask(td, uap->how, &set, &oset, 1); 1152 SIG2OSIG(oset, td->td_retval[0]); 1153 return (error); 1154 } 1155 #endif /* COMPAT_43 */ 1156 1157 int 1158 sys_sigwait(struct thread *td, struct sigwait_args *uap) 1159 { 1160 ksiginfo_t ksi; 1161 sigset_t set; 1162 int error; 1163 1164 error = copyin(uap->set, &set, sizeof(set)); 1165 if (error) { 1166 td->td_retval[0] = error; 1167 return (0); 1168 } 1169 1170 error = kern_sigtimedwait(td, set, &ksi, NULL); 1171 if (error) { 1172 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT) 1173 error = ERESTART; 1174 if (error == ERESTART) 1175 return (error); 1176 td->td_retval[0] = error; 1177 return (0); 1178 } 1179 1180 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo)); 1181 td->td_retval[0] = error; 1182 return (0); 1183 } 1184 1185 int 1186 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap) 1187 { 1188 struct timespec ts; 1189 struct timespec *timeout; 1190 sigset_t set; 1191 ksiginfo_t ksi; 1192 int error; 1193 1194 if (uap->timeout) { 1195 error = copyin(uap->timeout, &ts, sizeof(ts)); 1196 if (error) 1197 return (error); 1198 1199 timeout = &ts; 1200 } else 1201 timeout = NULL; 1202 1203 error = copyin(uap->set, &set, sizeof(set)); 1204 if (error) 1205 return (error); 1206 1207 error = kern_sigtimedwait(td, set, &ksi, timeout); 1208 if (error) 1209 return (error); 1210 1211 if (uap->info) 1212 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1213 1214 if (error == 0) 1215 td->td_retval[0] = ksi.ksi_signo; 1216 return (error); 1217 } 1218 1219 int 1220 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap) 1221 { 1222 ksiginfo_t ksi; 1223 sigset_t set; 1224 int error; 1225 1226 error = copyin(uap->set, &set, sizeof(set)); 1227 if (error) 1228 return (error); 1229 1230 error = kern_sigtimedwait(td, set, &ksi, NULL); 1231 if (error) 1232 return (error); 1233 1234 if (uap->info) 1235 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1236 1237 if (error == 0) 1238 td->td_retval[0] = ksi.ksi_signo; 1239 return (error); 1240 } 1241 1242 int 1243 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi, 1244 struct timespec *timeout) 1245 { 1246 struct sigacts *ps; 1247 sigset_t saved_mask, new_block; 1248 struct proc *p; 1249 int error, sig, timo, timevalid = 0; 1250 struct timespec rts, ets, ts; 1251 struct timeval tv; 1252 1253 p = td->td_proc; 1254 error = 0; 1255 ets.tv_sec = 0; 1256 ets.tv_nsec = 0; 1257 1258 if (timeout != NULL) { 1259 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { 1260 timevalid = 1; 1261 getnanouptime(&rts); 1262 ets = rts; 1263 timespecadd(&ets, timeout); 1264 } 1265 } 1266 ksiginfo_init(ksi); 1267 /* Some signals can not be waited for. */ 1268 SIG_CANTMASK(waitset); 1269 ps = p->p_sigacts; 1270 PROC_LOCK(p); 1271 saved_mask = td->td_sigmask; 1272 SIGSETNAND(td->td_sigmask, waitset); 1273 for (;;) { 1274 mtx_lock(&ps->ps_mtx); 1275 sig = cursig(td); 1276 mtx_unlock(&ps->ps_mtx); 1277 KASSERT(sig >= 0, ("sig %d", sig)); 1278 if (sig != 0 && SIGISMEMBER(waitset, sig)) { 1279 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 || 1280 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) { 1281 error = 0; 1282 break; 1283 } 1284 } 1285 1286 if (error != 0) 1287 break; 1288 1289 /* 1290 * POSIX says this must be checked after looking for pending 1291 * signals. 1292 */ 1293 if (timeout != NULL) { 1294 if (!timevalid) { 1295 error = EINVAL; 1296 break; 1297 } 1298 getnanouptime(&rts); 1299 if (timespeccmp(&rts, &ets, >=)) { 1300 error = EAGAIN; 1301 break; 1302 } 1303 ts = ets; 1304 timespecsub(&ts, &rts); 1305 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1306 timo = tvtohz(&tv); 1307 } else { 1308 timo = 0; 1309 } 1310 1311 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo); 1312 1313 if (timeout != NULL) { 1314 if (error == ERESTART) { 1315 /* Timeout can not be restarted. */ 1316 error = EINTR; 1317 } else if (error == EAGAIN) { 1318 /* We will calculate timeout by ourself. */ 1319 error = 0; 1320 } 1321 } 1322 } 1323 1324 new_block = saved_mask; 1325 SIGSETNAND(new_block, td->td_sigmask); 1326 td->td_sigmask = saved_mask; 1327 /* 1328 * Fewer signals can be delivered to us, reschedule signal 1329 * notification. 1330 */ 1331 if (p->p_numthreads != 1) 1332 reschedule_signals(p, new_block, 0); 1333 1334 if (error == 0) { 1335 SDT_PROBE2(proc, , , signal__clear, sig, ksi); 1336 1337 if (ksi->ksi_code == SI_TIMER) 1338 itimer_accept(p, ksi->ksi_timerid, ksi); 1339 1340 #ifdef KTRACE 1341 if (KTRPOINT(td, KTR_PSIG)) { 1342 sig_t action; 1343 1344 mtx_lock(&ps->ps_mtx); 1345 action = ps->ps_sigact[_SIG_IDX(sig)]; 1346 mtx_unlock(&ps->ps_mtx); 1347 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code); 1348 } 1349 #endif 1350 if (sig == SIGKILL) 1351 sigexit(td, sig); 1352 } 1353 PROC_UNLOCK(p); 1354 return (error); 1355 } 1356 1357 #ifndef _SYS_SYSPROTO_H_ 1358 struct sigpending_args { 1359 sigset_t *set; 1360 }; 1361 #endif 1362 int 1363 sys_sigpending(td, uap) 1364 struct thread *td; 1365 struct sigpending_args *uap; 1366 { 1367 struct proc *p = td->td_proc; 1368 sigset_t pending; 1369 1370 PROC_LOCK(p); 1371 pending = p->p_sigqueue.sq_signals; 1372 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1373 PROC_UNLOCK(p); 1374 return (copyout(&pending, uap->set, sizeof(sigset_t))); 1375 } 1376 1377 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1378 #ifndef _SYS_SYSPROTO_H_ 1379 struct osigpending_args { 1380 int dummy; 1381 }; 1382 #endif 1383 int 1384 osigpending(td, uap) 1385 struct thread *td; 1386 struct osigpending_args *uap; 1387 { 1388 struct proc *p = td->td_proc; 1389 sigset_t pending; 1390 1391 PROC_LOCK(p); 1392 pending = p->p_sigqueue.sq_signals; 1393 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1394 PROC_UNLOCK(p); 1395 SIG2OSIG(pending, td->td_retval[0]); 1396 return (0); 1397 } 1398 #endif /* COMPAT_43 */ 1399 1400 #if defined(COMPAT_43) 1401 /* 1402 * Generalized interface signal handler, 4.3-compatible. 1403 */ 1404 #ifndef _SYS_SYSPROTO_H_ 1405 struct osigvec_args { 1406 int signum; 1407 struct sigvec *nsv; 1408 struct sigvec *osv; 1409 }; 1410 #endif 1411 /* ARGSUSED */ 1412 int 1413 osigvec(td, uap) 1414 struct thread *td; 1415 register struct osigvec_args *uap; 1416 { 1417 struct sigvec vec; 1418 struct sigaction nsa, osa; 1419 register struct sigaction *nsap, *osap; 1420 int error; 1421 1422 if (uap->signum <= 0 || uap->signum >= ONSIG) 1423 return (EINVAL); 1424 nsap = (uap->nsv != NULL) ? &nsa : NULL; 1425 osap = (uap->osv != NULL) ? &osa : NULL; 1426 if (nsap) { 1427 error = copyin(uap->nsv, &vec, sizeof(vec)); 1428 if (error) 1429 return (error); 1430 nsap->sa_handler = vec.sv_handler; 1431 OSIG2SIG(vec.sv_mask, nsap->sa_mask); 1432 nsap->sa_flags = vec.sv_flags; 1433 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ 1434 } 1435 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 1436 if (osap && !error) { 1437 vec.sv_handler = osap->sa_handler; 1438 SIG2OSIG(osap->sa_mask, vec.sv_mask); 1439 vec.sv_flags = osap->sa_flags; 1440 vec.sv_flags &= ~SA_NOCLDWAIT; 1441 vec.sv_flags ^= SA_RESTART; 1442 error = copyout(&vec, uap->osv, sizeof(vec)); 1443 } 1444 return (error); 1445 } 1446 1447 #ifndef _SYS_SYSPROTO_H_ 1448 struct osigblock_args { 1449 int mask; 1450 }; 1451 #endif 1452 int 1453 osigblock(td, uap) 1454 register struct thread *td; 1455 struct osigblock_args *uap; 1456 { 1457 sigset_t set, oset; 1458 1459 OSIG2SIG(uap->mask, set); 1460 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0); 1461 SIG2OSIG(oset, td->td_retval[0]); 1462 return (0); 1463 } 1464 1465 #ifndef _SYS_SYSPROTO_H_ 1466 struct osigsetmask_args { 1467 int mask; 1468 }; 1469 #endif 1470 int 1471 osigsetmask(td, uap) 1472 struct thread *td; 1473 struct osigsetmask_args *uap; 1474 { 1475 sigset_t set, oset; 1476 1477 OSIG2SIG(uap->mask, set); 1478 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0); 1479 SIG2OSIG(oset, td->td_retval[0]); 1480 return (0); 1481 } 1482 #endif /* COMPAT_43 */ 1483 1484 /* 1485 * Suspend calling thread until signal, providing mask to be set in the 1486 * meantime. 1487 */ 1488 #ifndef _SYS_SYSPROTO_H_ 1489 struct sigsuspend_args { 1490 const sigset_t *sigmask; 1491 }; 1492 #endif 1493 /* ARGSUSED */ 1494 int 1495 sys_sigsuspend(td, uap) 1496 struct thread *td; 1497 struct sigsuspend_args *uap; 1498 { 1499 sigset_t mask; 1500 int error; 1501 1502 error = copyin(uap->sigmask, &mask, sizeof(mask)); 1503 if (error) 1504 return (error); 1505 return (kern_sigsuspend(td, mask)); 1506 } 1507 1508 int 1509 kern_sigsuspend(struct thread *td, sigset_t mask) 1510 { 1511 struct proc *p = td->td_proc; 1512 int has_sig, sig; 1513 1514 /* 1515 * When returning from sigsuspend, we want 1516 * the old mask to be restored after the 1517 * signal handler has finished. Thus, we 1518 * save it here and mark the sigacts structure 1519 * to indicate this. 1520 */ 1521 PROC_LOCK(p); 1522 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask, 1523 SIGPROCMASK_PROC_LOCKED); 1524 td->td_pflags |= TDP_OLDMASK; 1525 1526 /* 1527 * Process signals now. Otherwise, we can get spurious wakeup 1528 * due to signal entered process queue, but delivered to other 1529 * thread. But sigsuspend should return only on signal 1530 * delivery. 1531 */ 1532 (p->p_sysent->sv_set_syscall_retval)(td, EINTR); 1533 for (has_sig = 0; !has_sig;) { 1534 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 1535 0) == 0) 1536 /* void */; 1537 thread_suspend_check(0); 1538 mtx_lock(&p->p_sigacts->ps_mtx); 1539 while ((sig = cursig(td)) != 0) { 1540 KASSERT(sig >= 0, ("sig %d", sig)); 1541 has_sig += postsig(sig); 1542 } 1543 mtx_unlock(&p->p_sigacts->ps_mtx); 1544 } 1545 PROC_UNLOCK(p); 1546 td->td_errno = EINTR; 1547 td->td_pflags |= TDP_NERRNO; 1548 return (EJUSTRETURN); 1549 } 1550 1551 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1552 /* 1553 * Compatibility sigsuspend call for old binaries. Note nonstandard calling 1554 * convention: libc stub passes mask, not pointer, to save a copyin. 1555 */ 1556 #ifndef _SYS_SYSPROTO_H_ 1557 struct osigsuspend_args { 1558 osigset_t mask; 1559 }; 1560 #endif 1561 /* ARGSUSED */ 1562 int 1563 osigsuspend(td, uap) 1564 struct thread *td; 1565 struct osigsuspend_args *uap; 1566 { 1567 sigset_t mask; 1568 1569 OSIG2SIG(uap->mask, mask); 1570 return (kern_sigsuspend(td, mask)); 1571 } 1572 #endif /* COMPAT_43 */ 1573 1574 #if defined(COMPAT_43) 1575 #ifndef _SYS_SYSPROTO_H_ 1576 struct osigstack_args { 1577 struct sigstack *nss; 1578 struct sigstack *oss; 1579 }; 1580 #endif 1581 /* ARGSUSED */ 1582 int 1583 osigstack(td, uap) 1584 struct thread *td; 1585 register struct osigstack_args *uap; 1586 { 1587 struct sigstack nss, oss; 1588 int error = 0; 1589 1590 if (uap->nss != NULL) { 1591 error = copyin(uap->nss, &nss, sizeof(nss)); 1592 if (error) 1593 return (error); 1594 } 1595 oss.ss_sp = td->td_sigstk.ss_sp; 1596 oss.ss_onstack = sigonstack(cpu_getstack(td)); 1597 if (uap->nss != NULL) { 1598 td->td_sigstk.ss_sp = nss.ss_sp; 1599 td->td_sigstk.ss_size = 0; 1600 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK; 1601 td->td_pflags |= TDP_ALTSTACK; 1602 } 1603 if (uap->oss != NULL) 1604 error = copyout(&oss, uap->oss, sizeof(oss)); 1605 1606 return (error); 1607 } 1608 #endif /* COMPAT_43 */ 1609 1610 #ifndef _SYS_SYSPROTO_H_ 1611 struct sigaltstack_args { 1612 stack_t *ss; 1613 stack_t *oss; 1614 }; 1615 #endif 1616 /* ARGSUSED */ 1617 int 1618 sys_sigaltstack(td, uap) 1619 struct thread *td; 1620 register struct sigaltstack_args *uap; 1621 { 1622 stack_t ss, oss; 1623 int error; 1624 1625 if (uap->ss != NULL) { 1626 error = copyin(uap->ss, &ss, sizeof(ss)); 1627 if (error) 1628 return (error); 1629 } 1630 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL, 1631 (uap->oss != NULL) ? &oss : NULL); 1632 if (error) 1633 return (error); 1634 if (uap->oss != NULL) 1635 error = copyout(&oss, uap->oss, sizeof(stack_t)); 1636 return (error); 1637 } 1638 1639 int 1640 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss) 1641 { 1642 struct proc *p = td->td_proc; 1643 int oonstack; 1644 1645 oonstack = sigonstack(cpu_getstack(td)); 1646 1647 if (oss != NULL) { 1648 *oss = td->td_sigstk; 1649 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK) 1650 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 1651 } 1652 1653 if (ss != NULL) { 1654 if (oonstack) 1655 return (EPERM); 1656 if ((ss->ss_flags & ~SS_DISABLE) != 0) 1657 return (EINVAL); 1658 if (!(ss->ss_flags & SS_DISABLE)) { 1659 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 1660 return (ENOMEM); 1661 1662 td->td_sigstk = *ss; 1663 td->td_pflags |= TDP_ALTSTACK; 1664 } else { 1665 td->td_pflags &= ~TDP_ALTSTACK; 1666 } 1667 } 1668 return (0); 1669 } 1670 1671 /* 1672 * Common code for kill process group/broadcast kill. 1673 * cp is calling process. 1674 */ 1675 static int 1676 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi) 1677 { 1678 struct proc *p; 1679 struct pgrp *pgrp; 1680 int err; 1681 int ret; 1682 1683 ret = ESRCH; 1684 if (all) { 1685 /* 1686 * broadcast 1687 */ 1688 sx_slock(&allproc_lock); 1689 FOREACH_PROC_IN_SYSTEM(p) { 1690 PROC_LOCK(p); 1691 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 1692 p == td->td_proc || p->p_state == PRS_NEW) { 1693 PROC_UNLOCK(p); 1694 continue; 1695 } 1696 err = p_cansignal(td, p, sig); 1697 if (err == 0) { 1698 if (sig) 1699 pksignal(p, sig, ksi); 1700 ret = err; 1701 } 1702 else if (ret == ESRCH) 1703 ret = err; 1704 PROC_UNLOCK(p); 1705 } 1706 sx_sunlock(&allproc_lock); 1707 } else { 1708 sx_slock(&proctree_lock); 1709 if (pgid == 0) { 1710 /* 1711 * zero pgid means send to my process group. 1712 */ 1713 pgrp = td->td_proc->p_pgrp; 1714 PGRP_LOCK(pgrp); 1715 } else { 1716 pgrp = pgfind(pgid); 1717 if (pgrp == NULL) { 1718 sx_sunlock(&proctree_lock); 1719 return (ESRCH); 1720 } 1721 } 1722 sx_sunlock(&proctree_lock); 1723 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1724 PROC_LOCK(p); 1725 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 1726 p->p_state == PRS_NEW) { 1727 PROC_UNLOCK(p); 1728 continue; 1729 } 1730 err = p_cansignal(td, p, sig); 1731 if (err == 0) { 1732 if (sig) 1733 pksignal(p, sig, ksi); 1734 ret = err; 1735 } 1736 else if (ret == ESRCH) 1737 ret = err; 1738 PROC_UNLOCK(p); 1739 } 1740 PGRP_UNLOCK(pgrp); 1741 } 1742 return (ret); 1743 } 1744 1745 #ifndef _SYS_SYSPROTO_H_ 1746 struct kill_args { 1747 int pid; 1748 int signum; 1749 }; 1750 #endif 1751 /* ARGSUSED */ 1752 int 1753 sys_kill(struct thread *td, struct kill_args *uap) 1754 { 1755 ksiginfo_t ksi; 1756 struct proc *p; 1757 int error; 1758 1759 /* 1760 * A process in capability mode can send signals only to himself. 1761 * The main rationale behind this is that abort(3) is implemented as 1762 * kill(getpid(), SIGABRT). 1763 */ 1764 if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid) 1765 return (ECAPMODE); 1766 1767 AUDIT_ARG_SIGNUM(uap->signum); 1768 AUDIT_ARG_PID(uap->pid); 1769 if ((u_int)uap->signum > _SIG_MAXSIG) 1770 return (EINVAL); 1771 1772 ksiginfo_init(&ksi); 1773 ksi.ksi_signo = uap->signum; 1774 ksi.ksi_code = SI_USER; 1775 ksi.ksi_pid = td->td_proc->p_pid; 1776 ksi.ksi_uid = td->td_ucred->cr_ruid; 1777 1778 if (uap->pid > 0) { 1779 /* kill single process */ 1780 if ((p = pfind(uap->pid)) == NULL) { 1781 if ((p = zpfind(uap->pid)) == NULL) 1782 return (ESRCH); 1783 } 1784 AUDIT_ARG_PROCESS(p); 1785 error = p_cansignal(td, p, uap->signum); 1786 if (error == 0 && uap->signum) 1787 pksignal(p, uap->signum, &ksi); 1788 PROC_UNLOCK(p); 1789 return (error); 1790 } 1791 switch (uap->pid) { 1792 case -1: /* broadcast signal */ 1793 return (killpg1(td, uap->signum, 0, 1, &ksi)); 1794 case 0: /* signal own process group */ 1795 return (killpg1(td, uap->signum, 0, 0, &ksi)); 1796 default: /* negative explicit process group */ 1797 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi)); 1798 } 1799 /* NOTREACHED */ 1800 } 1801 1802 int 1803 sys_pdkill(td, uap) 1804 struct thread *td; 1805 struct pdkill_args *uap; 1806 { 1807 struct proc *p; 1808 cap_rights_t rights; 1809 int error; 1810 1811 AUDIT_ARG_SIGNUM(uap->signum); 1812 AUDIT_ARG_FD(uap->fd); 1813 if ((u_int)uap->signum > _SIG_MAXSIG) 1814 return (EINVAL); 1815 1816 error = procdesc_find(td, uap->fd, 1817 cap_rights_init(&rights, CAP_PDKILL), &p); 1818 if (error) 1819 return (error); 1820 AUDIT_ARG_PROCESS(p); 1821 error = p_cansignal(td, p, uap->signum); 1822 if (error == 0 && uap->signum) 1823 kern_psignal(p, uap->signum); 1824 PROC_UNLOCK(p); 1825 return (error); 1826 } 1827 1828 #if defined(COMPAT_43) 1829 #ifndef _SYS_SYSPROTO_H_ 1830 struct okillpg_args { 1831 int pgid; 1832 int signum; 1833 }; 1834 #endif 1835 /* ARGSUSED */ 1836 int 1837 okillpg(struct thread *td, struct okillpg_args *uap) 1838 { 1839 ksiginfo_t ksi; 1840 1841 AUDIT_ARG_SIGNUM(uap->signum); 1842 AUDIT_ARG_PID(uap->pgid); 1843 if ((u_int)uap->signum > _SIG_MAXSIG) 1844 return (EINVAL); 1845 1846 ksiginfo_init(&ksi); 1847 ksi.ksi_signo = uap->signum; 1848 ksi.ksi_code = SI_USER; 1849 ksi.ksi_pid = td->td_proc->p_pid; 1850 ksi.ksi_uid = td->td_ucred->cr_ruid; 1851 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi)); 1852 } 1853 #endif /* COMPAT_43 */ 1854 1855 #ifndef _SYS_SYSPROTO_H_ 1856 struct sigqueue_args { 1857 pid_t pid; 1858 int signum; 1859 /* union sigval */ void *value; 1860 }; 1861 #endif 1862 int 1863 sys_sigqueue(struct thread *td, struct sigqueue_args *uap) 1864 { 1865 union sigval sv; 1866 1867 sv.sival_ptr = uap->value; 1868 1869 return (kern_sigqueue(td, uap->pid, uap->signum, &sv)); 1870 } 1871 1872 int 1873 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value) 1874 { 1875 ksiginfo_t ksi; 1876 struct proc *p; 1877 int error; 1878 1879 if ((u_int)signum > _SIG_MAXSIG) 1880 return (EINVAL); 1881 1882 /* 1883 * Specification says sigqueue can only send signal to 1884 * single process. 1885 */ 1886 if (pid <= 0) 1887 return (EINVAL); 1888 1889 if ((p = pfind(pid)) == NULL) { 1890 if ((p = zpfind(pid)) == NULL) 1891 return (ESRCH); 1892 } 1893 error = p_cansignal(td, p, signum); 1894 if (error == 0 && signum != 0) { 1895 ksiginfo_init(&ksi); 1896 ksi.ksi_flags = KSI_SIGQ; 1897 ksi.ksi_signo = signum; 1898 ksi.ksi_code = SI_QUEUE; 1899 ksi.ksi_pid = td->td_proc->p_pid; 1900 ksi.ksi_uid = td->td_ucred->cr_ruid; 1901 ksi.ksi_value = *value; 1902 error = pksignal(p, ksi.ksi_signo, &ksi); 1903 } 1904 PROC_UNLOCK(p); 1905 return (error); 1906 } 1907 1908 /* 1909 * Send a signal to a process group. 1910 */ 1911 void 1912 gsignal(int pgid, int sig, ksiginfo_t *ksi) 1913 { 1914 struct pgrp *pgrp; 1915 1916 if (pgid != 0) { 1917 sx_slock(&proctree_lock); 1918 pgrp = pgfind(pgid); 1919 sx_sunlock(&proctree_lock); 1920 if (pgrp != NULL) { 1921 pgsignal(pgrp, sig, 0, ksi); 1922 PGRP_UNLOCK(pgrp); 1923 } 1924 } 1925 } 1926 1927 /* 1928 * Send a signal to a process group. If checktty is 1, 1929 * limit to members which have a controlling terminal. 1930 */ 1931 void 1932 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi) 1933 { 1934 struct proc *p; 1935 1936 if (pgrp) { 1937 PGRP_LOCK_ASSERT(pgrp, MA_OWNED); 1938 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1939 PROC_LOCK(p); 1940 if (p->p_state == PRS_NORMAL && 1941 (checkctty == 0 || p->p_flag & P_CONTROLT)) 1942 pksignal(p, sig, ksi); 1943 PROC_UNLOCK(p); 1944 } 1945 } 1946 } 1947 1948 1949 /* 1950 * Recalculate the signal mask and reset the signal disposition after 1951 * usermode frame for delivery is formed. Should be called after 1952 * mach-specific routine, because sysent->sv_sendsig() needs correct 1953 * ps_siginfo and signal mask. 1954 */ 1955 static void 1956 postsig_done(int sig, struct thread *td, struct sigacts *ps) 1957 { 1958 sigset_t mask; 1959 1960 mtx_assert(&ps->ps_mtx, MA_OWNED); 1961 td->td_ru.ru_nsignals++; 1962 mask = ps->ps_catchmask[_SIG_IDX(sig)]; 1963 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1964 SIGADDSET(mask, sig); 1965 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, 1966 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); 1967 if (SIGISMEMBER(ps->ps_sigreset, sig)) 1968 sigdflt(ps, sig); 1969 } 1970 1971 1972 /* 1973 * Send a signal caused by a trap to the current thread. If it will be 1974 * caught immediately, deliver it with correct code. Otherwise, post it 1975 * normally. 1976 */ 1977 void 1978 trapsignal(struct thread *td, ksiginfo_t *ksi) 1979 { 1980 struct sigacts *ps; 1981 struct proc *p; 1982 int sig; 1983 int code; 1984 1985 p = td->td_proc; 1986 sig = ksi->ksi_signo; 1987 code = ksi->ksi_code; 1988 KASSERT(_SIG_VALID(sig), ("invalid signal")); 1989 1990 PROC_LOCK(p); 1991 ps = p->p_sigacts; 1992 mtx_lock(&ps->ps_mtx); 1993 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) && 1994 !SIGISMEMBER(td->td_sigmask, sig)) { 1995 #ifdef KTRACE 1996 if (KTRPOINT(curthread, KTR_PSIG)) 1997 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)], 1998 &td->td_sigmask, code); 1999 #endif 2000 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], 2001 ksi, &td->td_sigmask); 2002 postsig_done(sig, td, ps); 2003 mtx_unlock(&ps->ps_mtx); 2004 } else { 2005 /* 2006 * Avoid a possible infinite loop if the thread 2007 * masking the signal or process is ignoring the 2008 * signal. 2009 */ 2010 if (kern_forcesigexit && 2011 (SIGISMEMBER(td->td_sigmask, sig) || 2012 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) { 2013 SIGDELSET(td->td_sigmask, sig); 2014 SIGDELSET(ps->ps_sigcatch, sig); 2015 SIGDELSET(ps->ps_sigignore, sig); 2016 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2017 } 2018 mtx_unlock(&ps->ps_mtx); 2019 p->p_code = code; /* XXX for core dump/debugger */ 2020 p->p_sig = sig; /* XXX to verify code */ 2021 tdsendsignal(p, td, sig, ksi); 2022 } 2023 PROC_UNLOCK(p); 2024 } 2025 2026 static struct thread * 2027 sigtd(struct proc *p, int sig, int prop) 2028 { 2029 struct thread *td, *signal_td; 2030 2031 PROC_LOCK_ASSERT(p, MA_OWNED); 2032 2033 /* 2034 * Check if current thread can handle the signal without 2035 * switching context to another thread. 2036 */ 2037 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig)) 2038 return (curthread); 2039 signal_td = NULL; 2040 FOREACH_THREAD_IN_PROC(p, td) { 2041 if (!SIGISMEMBER(td->td_sigmask, sig)) { 2042 signal_td = td; 2043 break; 2044 } 2045 } 2046 if (signal_td == NULL) 2047 signal_td = FIRST_THREAD_IN_PROC(p); 2048 return (signal_td); 2049 } 2050 2051 /* 2052 * Send the signal to the process. If the signal has an action, the action 2053 * is usually performed by the target process rather than the caller; we add 2054 * the signal to the set of pending signals for the process. 2055 * 2056 * Exceptions: 2057 * o When a stop signal is sent to a sleeping process that takes the 2058 * default action, the process is stopped without awakening it. 2059 * o SIGCONT restarts stopped processes (or puts them back to sleep) 2060 * regardless of the signal action (eg, blocked or ignored). 2061 * 2062 * Other ignored signals are discarded immediately. 2063 * 2064 * NB: This function may be entered from the debugger via the "kill" DDB 2065 * command. There is little that can be done to mitigate the possibly messy 2066 * side effects of this unwise possibility. 2067 */ 2068 void 2069 kern_psignal(struct proc *p, int sig) 2070 { 2071 ksiginfo_t ksi; 2072 2073 ksiginfo_init(&ksi); 2074 ksi.ksi_signo = sig; 2075 ksi.ksi_code = SI_KERNEL; 2076 (void) tdsendsignal(p, NULL, sig, &ksi); 2077 } 2078 2079 int 2080 pksignal(struct proc *p, int sig, ksiginfo_t *ksi) 2081 { 2082 2083 return (tdsendsignal(p, NULL, sig, ksi)); 2084 } 2085 2086 /* Utility function for finding a thread to send signal event to. */ 2087 int 2088 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd) 2089 { 2090 struct thread *td; 2091 2092 if (sigev->sigev_notify == SIGEV_THREAD_ID) { 2093 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid); 2094 if (td == NULL) 2095 return (ESRCH); 2096 *ttd = td; 2097 } else { 2098 *ttd = NULL; 2099 PROC_LOCK(p); 2100 } 2101 return (0); 2102 } 2103 2104 void 2105 tdsignal(struct thread *td, int sig) 2106 { 2107 ksiginfo_t ksi; 2108 2109 ksiginfo_init(&ksi); 2110 ksi.ksi_signo = sig; 2111 ksi.ksi_code = SI_KERNEL; 2112 (void) tdsendsignal(td->td_proc, td, sig, &ksi); 2113 } 2114 2115 void 2116 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi) 2117 { 2118 2119 (void) tdsendsignal(td->td_proc, td, sig, ksi); 2120 } 2121 2122 int 2123 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) 2124 { 2125 sig_t action; 2126 sigqueue_t *sigqueue; 2127 int prop; 2128 struct sigacts *ps; 2129 int intrval; 2130 int ret = 0; 2131 int wakeup_swapper; 2132 2133 MPASS(td == NULL || p == td->td_proc); 2134 PROC_LOCK_ASSERT(p, MA_OWNED); 2135 2136 if (!_SIG_VALID(sig)) 2137 panic("%s(): invalid signal %d", __func__, sig); 2138 2139 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__)); 2140 2141 /* 2142 * IEEE Std 1003.1-2001: return success when killing a zombie. 2143 */ 2144 if (p->p_state == PRS_ZOMBIE) { 2145 if (ksi && (ksi->ksi_flags & KSI_INS)) 2146 ksiginfo_tryfree(ksi); 2147 return (ret); 2148 } 2149 2150 ps = p->p_sigacts; 2151 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig); 2152 prop = sigprop(sig); 2153 2154 if (td == NULL) { 2155 td = sigtd(p, sig, prop); 2156 sigqueue = &p->p_sigqueue; 2157 } else 2158 sigqueue = &td->td_sigqueue; 2159 2160 SDT_PROBE3(proc, , , signal__send, td, p, sig); 2161 2162 /* 2163 * If the signal is being ignored, 2164 * then we forget about it immediately. 2165 * (Note: we don't set SIGCONT in ps_sigignore, 2166 * and if it is set to SIG_IGN, 2167 * action will be SIG_DFL here.) 2168 */ 2169 mtx_lock(&ps->ps_mtx); 2170 if (SIGISMEMBER(ps->ps_sigignore, sig)) { 2171 SDT_PROBE3(proc, , , signal__discard, td, p, sig); 2172 2173 mtx_unlock(&ps->ps_mtx); 2174 if (ksi && (ksi->ksi_flags & KSI_INS)) 2175 ksiginfo_tryfree(ksi); 2176 return (ret); 2177 } 2178 if (SIGISMEMBER(td->td_sigmask, sig)) 2179 action = SIG_HOLD; 2180 else if (SIGISMEMBER(ps->ps_sigcatch, sig)) 2181 action = SIG_CATCH; 2182 else 2183 action = SIG_DFL; 2184 if (SIGISMEMBER(ps->ps_sigintr, sig)) 2185 intrval = EINTR; 2186 else 2187 intrval = ERESTART; 2188 mtx_unlock(&ps->ps_mtx); 2189 2190 if (prop & SA_CONT) 2191 sigqueue_delete_stopmask_proc(p); 2192 else if (prop & SA_STOP) { 2193 /* 2194 * If sending a tty stop signal to a member of an orphaned 2195 * process group, discard the signal here if the action 2196 * is default; don't stop the process below if sleeping, 2197 * and don't clear any pending SIGCONT. 2198 */ 2199 if ((prop & SA_TTYSTOP) && 2200 (p->p_pgrp->pg_jobc == 0) && 2201 (action == SIG_DFL)) { 2202 if (ksi && (ksi->ksi_flags & KSI_INS)) 2203 ksiginfo_tryfree(ksi); 2204 return (ret); 2205 } 2206 sigqueue_delete_proc(p, SIGCONT); 2207 if (p->p_flag & P_CONTINUED) { 2208 p->p_flag &= ~P_CONTINUED; 2209 PROC_LOCK(p->p_pptr); 2210 sigqueue_take(p->p_ksi); 2211 PROC_UNLOCK(p->p_pptr); 2212 } 2213 } 2214 2215 ret = sigqueue_add(sigqueue, sig, ksi); 2216 if (ret != 0) 2217 return (ret); 2218 signotify(td); 2219 /* 2220 * Defer further processing for signals which are held, 2221 * except that stopped processes must be continued by SIGCONT. 2222 */ 2223 if (action == SIG_HOLD && 2224 !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG))) 2225 return (ret); 2226 2227 /* SIGKILL: Remove procfs STOPEVENTs. */ 2228 if (sig == SIGKILL) { 2229 /* from procfs_ioctl.c: PIOCBIC */ 2230 p->p_stops = 0; 2231 /* from procfs_ioctl.c: PIOCCONT */ 2232 p->p_step = 0; 2233 wakeup(&p->p_step); 2234 } 2235 /* 2236 * Some signals have a process-wide effect and a per-thread 2237 * component. Most processing occurs when the process next 2238 * tries to cross the user boundary, however there are some 2239 * times when processing needs to be done immediately, such as 2240 * waking up threads so that they can cross the user boundary. 2241 * We try to do the per-process part here. 2242 */ 2243 if (P_SHOULDSTOP(p)) { 2244 KASSERT(!(p->p_flag & P_WEXIT), 2245 ("signal to stopped but exiting process")); 2246 if (sig == SIGKILL) { 2247 /* 2248 * If traced process is already stopped, 2249 * then no further action is necessary. 2250 */ 2251 if (p->p_flag & P_TRACED) 2252 goto out; 2253 /* 2254 * SIGKILL sets process running. 2255 * It will die elsewhere. 2256 * All threads must be restarted. 2257 */ 2258 p->p_flag &= ~P_STOPPED_SIG; 2259 goto runfast; 2260 } 2261 2262 if (prop & SA_CONT) { 2263 /* 2264 * If traced process is already stopped, 2265 * then no further action is necessary. 2266 */ 2267 if (p->p_flag & P_TRACED) 2268 goto out; 2269 /* 2270 * If SIGCONT is default (or ignored), we continue the 2271 * process but don't leave the signal in sigqueue as 2272 * it has no further action. If SIGCONT is held, we 2273 * continue the process and leave the signal in 2274 * sigqueue. If the process catches SIGCONT, let it 2275 * handle the signal itself. If it isn't waiting on 2276 * an event, it goes back to run state. 2277 * Otherwise, process goes back to sleep state. 2278 */ 2279 p->p_flag &= ~P_STOPPED_SIG; 2280 PROC_SLOCK(p); 2281 if (p->p_numthreads == p->p_suspcount) { 2282 PROC_SUNLOCK(p); 2283 p->p_flag |= P_CONTINUED; 2284 p->p_xsig = SIGCONT; 2285 PROC_LOCK(p->p_pptr); 2286 childproc_continued(p); 2287 PROC_UNLOCK(p->p_pptr); 2288 PROC_SLOCK(p); 2289 } 2290 if (action == SIG_DFL) { 2291 thread_unsuspend(p); 2292 PROC_SUNLOCK(p); 2293 sigqueue_delete(sigqueue, sig); 2294 goto out; 2295 } 2296 if (action == SIG_CATCH) { 2297 /* 2298 * The process wants to catch it so it needs 2299 * to run at least one thread, but which one? 2300 */ 2301 PROC_SUNLOCK(p); 2302 goto runfast; 2303 } 2304 /* 2305 * The signal is not ignored or caught. 2306 */ 2307 thread_unsuspend(p); 2308 PROC_SUNLOCK(p); 2309 goto out; 2310 } 2311 2312 if (prop & SA_STOP) { 2313 /* 2314 * If traced process is already stopped, 2315 * then no further action is necessary. 2316 */ 2317 if (p->p_flag & P_TRACED) 2318 goto out; 2319 /* 2320 * Already stopped, don't need to stop again 2321 * (If we did the shell could get confused). 2322 * Just make sure the signal STOP bit set. 2323 */ 2324 p->p_flag |= P_STOPPED_SIG; 2325 sigqueue_delete(sigqueue, sig); 2326 goto out; 2327 } 2328 2329 /* 2330 * All other kinds of signals: 2331 * If a thread is sleeping interruptibly, simulate a 2332 * wakeup so that when it is continued it will be made 2333 * runnable and can look at the signal. However, don't make 2334 * the PROCESS runnable, leave it stopped. 2335 * It may run a bit until it hits a thread_suspend_check(). 2336 */ 2337 wakeup_swapper = 0; 2338 PROC_SLOCK(p); 2339 thread_lock(td); 2340 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR)) 2341 wakeup_swapper = sleepq_abort(td, intrval); 2342 thread_unlock(td); 2343 PROC_SUNLOCK(p); 2344 if (wakeup_swapper) 2345 kick_proc0(); 2346 goto out; 2347 /* 2348 * Mutexes are short lived. Threads waiting on them will 2349 * hit thread_suspend_check() soon. 2350 */ 2351 } else if (p->p_state == PRS_NORMAL) { 2352 if (p->p_flag & P_TRACED || action == SIG_CATCH) { 2353 tdsigwakeup(td, sig, action, intrval); 2354 goto out; 2355 } 2356 2357 MPASS(action == SIG_DFL); 2358 2359 if (prop & SA_STOP) { 2360 if (p->p_flag & (P_PPWAIT|P_WEXIT)) 2361 goto out; 2362 p->p_flag |= P_STOPPED_SIG; 2363 p->p_xsig = sig; 2364 PROC_SLOCK(p); 2365 wakeup_swapper = sig_suspend_threads(td, p, 1); 2366 if (p->p_numthreads == p->p_suspcount) { 2367 /* 2368 * only thread sending signal to another 2369 * process can reach here, if thread is sending 2370 * signal to its process, because thread does 2371 * not suspend itself here, p_numthreads 2372 * should never be equal to p_suspcount. 2373 */ 2374 thread_stopped(p); 2375 PROC_SUNLOCK(p); 2376 sigqueue_delete_proc(p, p->p_xsig); 2377 } else 2378 PROC_SUNLOCK(p); 2379 if (wakeup_swapper) 2380 kick_proc0(); 2381 goto out; 2382 } 2383 } else { 2384 /* Not in "NORMAL" state. discard the signal. */ 2385 sigqueue_delete(sigqueue, sig); 2386 goto out; 2387 } 2388 2389 /* 2390 * The process is not stopped so we need to apply the signal to all the 2391 * running threads. 2392 */ 2393 runfast: 2394 tdsigwakeup(td, sig, action, intrval); 2395 PROC_SLOCK(p); 2396 thread_unsuspend(p); 2397 PROC_SUNLOCK(p); 2398 out: 2399 /* If we jump here, proc slock should not be owned. */ 2400 PROC_SLOCK_ASSERT(p, MA_NOTOWNED); 2401 return (ret); 2402 } 2403 2404 /* 2405 * The force of a signal has been directed against a single 2406 * thread. We need to see what we can do about knocking it 2407 * out of any sleep it may be in etc. 2408 */ 2409 static void 2410 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval) 2411 { 2412 struct proc *p = td->td_proc; 2413 register int prop; 2414 int wakeup_swapper; 2415 2416 wakeup_swapper = 0; 2417 PROC_LOCK_ASSERT(p, MA_OWNED); 2418 prop = sigprop(sig); 2419 2420 PROC_SLOCK(p); 2421 thread_lock(td); 2422 /* 2423 * Bring the priority of a thread up if we want it to get 2424 * killed in this lifetime. Be careful to avoid bumping the 2425 * priority of the idle thread, since we still allow to signal 2426 * kernel processes. 2427 */ 2428 if (action == SIG_DFL && (prop & SA_KILL) != 0 && 2429 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2430 sched_prio(td, PUSER); 2431 if (TD_ON_SLEEPQ(td)) { 2432 /* 2433 * If thread is sleeping uninterruptibly 2434 * we can't interrupt the sleep... the signal will 2435 * be noticed when the process returns through 2436 * trap() or syscall(). 2437 */ 2438 if ((td->td_flags & TDF_SINTR) == 0) 2439 goto out; 2440 /* 2441 * If SIGCONT is default (or ignored) and process is 2442 * asleep, we are finished; the process should not 2443 * be awakened. 2444 */ 2445 if ((prop & SA_CONT) && action == SIG_DFL) { 2446 thread_unlock(td); 2447 PROC_SUNLOCK(p); 2448 sigqueue_delete(&p->p_sigqueue, sig); 2449 /* 2450 * It may be on either list in this state. 2451 * Remove from both for now. 2452 */ 2453 sigqueue_delete(&td->td_sigqueue, sig); 2454 return; 2455 } 2456 2457 /* 2458 * Don't awaken a sleeping thread for SIGSTOP if the 2459 * STOP signal is deferred. 2460 */ 2461 if ((prop & SA_STOP) != 0 && (td->td_flags & (TDF_SBDRY | 2462 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2463 goto out; 2464 2465 /* 2466 * Give low priority threads a better chance to run. 2467 */ 2468 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2469 sched_prio(td, PUSER); 2470 2471 wakeup_swapper = sleepq_abort(td, intrval); 2472 } else { 2473 /* 2474 * Other states do nothing with the signal immediately, 2475 * other than kicking ourselves if we are running. 2476 * It will either never be noticed, or noticed very soon. 2477 */ 2478 #ifdef SMP 2479 if (TD_IS_RUNNING(td) && td != curthread) 2480 forward_signal(td); 2481 #endif 2482 } 2483 out: 2484 PROC_SUNLOCK(p); 2485 thread_unlock(td); 2486 if (wakeup_swapper) 2487 kick_proc0(); 2488 } 2489 2490 static int 2491 sig_suspend_threads(struct thread *td, struct proc *p, int sending) 2492 { 2493 struct thread *td2; 2494 int wakeup_swapper; 2495 2496 PROC_LOCK_ASSERT(p, MA_OWNED); 2497 PROC_SLOCK_ASSERT(p, MA_OWNED); 2498 MPASS(sending || td == curthread); 2499 2500 wakeup_swapper = 0; 2501 FOREACH_THREAD_IN_PROC(p, td2) { 2502 thread_lock(td2); 2503 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK; 2504 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) && 2505 (td2->td_flags & TDF_SINTR)) { 2506 if (td2->td_flags & TDF_SBDRY) { 2507 /* 2508 * Once a thread is asleep with 2509 * TDF_SBDRY and without TDF_SERESTART 2510 * or TDF_SEINTR set, it should never 2511 * become suspended due to this check. 2512 */ 2513 KASSERT(!TD_IS_SUSPENDED(td2), 2514 ("thread with deferred stops suspended")); 2515 if (TD_SBDRY_INTR(td2)) 2516 wakeup_swapper |= sleepq_abort(td2, 2517 TD_SBDRY_ERRNO(td2)); 2518 } else if (!TD_IS_SUSPENDED(td2)) { 2519 thread_suspend_one(td2); 2520 } 2521 } else if (!TD_IS_SUSPENDED(td2)) { 2522 if (sending || td != td2) 2523 td2->td_flags |= TDF_ASTPENDING; 2524 #ifdef SMP 2525 if (TD_IS_RUNNING(td2) && td2 != td) 2526 forward_signal(td2); 2527 #endif 2528 } 2529 thread_unlock(td2); 2530 } 2531 return (wakeup_swapper); 2532 } 2533 2534 /* 2535 * Stop the process for an event deemed interesting to the debugger. If si is 2536 * non-NULL, this is a signal exchange; the new signal requested by the 2537 * debugger will be returned for handling. If si is NULL, this is some other 2538 * type of interesting event. The debugger may request a signal be delivered in 2539 * that case as well, however it will be deferred until it can be handled. 2540 */ 2541 int 2542 ptracestop(struct thread *td, int sig, ksiginfo_t *si) 2543 { 2544 struct proc *p = td->td_proc; 2545 struct thread *td2; 2546 ksiginfo_t ksi; 2547 int prop; 2548 2549 PROC_LOCK_ASSERT(p, MA_OWNED); 2550 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); 2551 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2552 &p->p_mtx.lock_object, "Stopping for traced signal"); 2553 2554 td->td_xsig = sig; 2555 2556 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) { 2557 td->td_dbgflags |= TDB_XSIG; 2558 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d", 2559 td->td_tid, p->p_pid, td->td_dbgflags, sig); 2560 PROC_SLOCK(p); 2561 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) { 2562 if (P_KILLED(p)) { 2563 /* 2564 * Ensure that, if we've been PT_KILLed, the 2565 * exit status reflects that. Another thread 2566 * may also be in ptracestop(), having just 2567 * received the SIGKILL, but this thread was 2568 * unsuspended first. 2569 */ 2570 td->td_dbgflags &= ~TDB_XSIG; 2571 td->td_xsig = SIGKILL; 2572 p->p_ptevents = 0; 2573 break; 2574 } 2575 if (p->p_flag & P_SINGLE_EXIT && 2576 !(td->td_dbgflags & TDB_EXIT)) { 2577 /* 2578 * Ignore ptrace stops except for thread exit 2579 * events when the process exits. 2580 */ 2581 td->td_dbgflags &= ~TDB_XSIG; 2582 PROC_SUNLOCK(p); 2583 return (0); 2584 } 2585 2586 /* 2587 * Make wait(2) work. Ensure that right after the 2588 * attach, the thread which was decided to become the 2589 * leader of attach gets reported to the waiter. 2590 * Otherwise, just avoid overwriting another thread's 2591 * assignment to p_xthread. If another thread has 2592 * already set p_xthread, the current thread will get 2593 * a chance to report itself upon the next iteration. 2594 */ 2595 if ((td->td_dbgflags & TDB_FSTP) != 0 || 2596 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 && 2597 p->p_xthread == NULL)) { 2598 p->p_xsig = sig; 2599 p->p_xthread = td; 2600 td->td_dbgflags &= ~TDB_FSTP; 2601 p->p_flag2 &= ~P2_PTRACE_FSTP; 2602 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE; 2603 sig_suspend_threads(td, p, 0); 2604 } 2605 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) { 2606 td->td_dbgflags &= ~TDB_STOPATFORK; 2607 cv_broadcast(&p->p_dbgwait); 2608 } 2609 stopme: 2610 thread_suspend_switch(td, p); 2611 if (p->p_xthread == td) 2612 p->p_xthread = NULL; 2613 if (!(p->p_flag & P_TRACED)) 2614 break; 2615 if (td->td_dbgflags & TDB_SUSPEND) { 2616 if (p->p_flag & P_SINGLE_EXIT) 2617 break; 2618 goto stopme; 2619 } 2620 } 2621 PROC_SUNLOCK(p); 2622 } 2623 2624 if (si != NULL && sig == td->td_xsig) { 2625 /* Parent wants us to take the original signal unchanged. */ 2626 si->ksi_flags |= KSI_HEAD; 2627 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0) 2628 si->ksi_signo = 0; 2629 } else if (td->td_xsig != 0) { 2630 /* 2631 * If parent wants us to take a new signal, then it will leave 2632 * it in td->td_xsig; otherwise we just look for signals again. 2633 */ 2634 ksiginfo_init(&ksi); 2635 ksi.ksi_signo = td->td_xsig; 2636 ksi.ksi_flags |= KSI_PTRACE; 2637 prop = sigprop(td->td_xsig); 2638 td2 = sigtd(p, td->td_xsig, prop); 2639 tdsendsignal(p, td2, td->td_xsig, &ksi); 2640 if (td != td2) 2641 return (0); 2642 } 2643 2644 return (td->td_xsig); 2645 } 2646 2647 static void 2648 reschedule_signals(struct proc *p, sigset_t block, int flags) 2649 { 2650 struct sigacts *ps; 2651 struct thread *td; 2652 int sig; 2653 2654 PROC_LOCK_ASSERT(p, MA_OWNED); 2655 ps = p->p_sigacts; 2656 mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ? 2657 MA_OWNED : MA_NOTOWNED); 2658 if (SIGISEMPTY(p->p_siglist)) 2659 return; 2660 SIGSETAND(block, p->p_siglist); 2661 while ((sig = sig_ffs(&block)) != 0) { 2662 SIGDELSET(block, sig); 2663 td = sigtd(p, sig, 0); 2664 signotify(td); 2665 if (!(flags & SIGPROCMASK_PS_LOCKED)) 2666 mtx_lock(&ps->ps_mtx); 2667 if (p->p_flag & P_TRACED || 2668 (SIGISMEMBER(ps->ps_sigcatch, sig) && 2669 !SIGISMEMBER(td->td_sigmask, sig))) 2670 tdsigwakeup(td, sig, SIG_CATCH, 2671 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : 2672 ERESTART)); 2673 if (!(flags & SIGPROCMASK_PS_LOCKED)) 2674 mtx_unlock(&ps->ps_mtx); 2675 } 2676 } 2677 2678 void 2679 tdsigcleanup(struct thread *td) 2680 { 2681 struct proc *p; 2682 sigset_t unblocked; 2683 2684 p = td->td_proc; 2685 PROC_LOCK_ASSERT(p, MA_OWNED); 2686 2687 sigqueue_flush(&td->td_sigqueue); 2688 if (p->p_numthreads == 1) 2689 return; 2690 2691 /* 2692 * Since we cannot handle signals, notify signal post code 2693 * about this by filling the sigmask. 2694 * 2695 * Also, if needed, wake up thread(s) that do not block the 2696 * same signals as the exiting thread, since the thread might 2697 * have been selected for delivery and woken up. 2698 */ 2699 SIGFILLSET(unblocked); 2700 SIGSETNAND(unblocked, td->td_sigmask); 2701 SIGFILLSET(td->td_sigmask); 2702 reschedule_signals(p, unblocked, 0); 2703 2704 } 2705 2706 static int 2707 sigdeferstop_curr_flags(int cflags) 2708 { 2709 2710 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 || 2711 (cflags & TDF_SBDRY) != 0); 2712 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)); 2713 } 2714 2715 /* 2716 * Defer the delivery of SIGSTOP for the current thread, according to 2717 * the requested mode. Returns previous flags, which must be restored 2718 * by sigallowstop(). 2719 * 2720 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and 2721 * cleared by the current thread, which allow the lock-less read-only 2722 * accesses below. 2723 */ 2724 int 2725 sigdeferstop_impl(int mode) 2726 { 2727 struct thread *td; 2728 int cflags, nflags; 2729 2730 td = curthread; 2731 cflags = sigdeferstop_curr_flags(td->td_flags); 2732 switch (mode) { 2733 case SIGDEFERSTOP_NOP: 2734 nflags = cflags; 2735 break; 2736 case SIGDEFERSTOP_OFF: 2737 nflags = 0; 2738 break; 2739 case SIGDEFERSTOP_SILENT: 2740 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART); 2741 break; 2742 case SIGDEFERSTOP_EINTR: 2743 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART; 2744 break; 2745 case SIGDEFERSTOP_ERESTART: 2746 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR; 2747 break; 2748 default: 2749 panic("sigdeferstop: invalid mode %x", mode); 2750 break; 2751 } 2752 if (cflags == nflags) 2753 return (SIGDEFERSTOP_VAL_NCHG); 2754 thread_lock(td); 2755 td->td_flags = (td->td_flags & ~cflags) | nflags; 2756 thread_unlock(td); 2757 return (cflags); 2758 } 2759 2760 /* 2761 * Restores the STOP handling mode, typically permitting the delivery 2762 * of SIGSTOP for the current thread. This does not immediately 2763 * suspend if a stop was posted. Instead, the thread will suspend 2764 * either via ast() or a subsequent interruptible sleep. 2765 */ 2766 void 2767 sigallowstop_impl(int prev) 2768 { 2769 struct thread *td; 2770 int cflags; 2771 2772 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop")); 2773 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0, 2774 ("sigallowstop: incorrect previous mode %x", prev)); 2775 td = curthread; 2776 cflags = sigdeferstop_curr_flags(td->td_flags); 2777 if (cflags != prev) { 2778 thread_lock(td); 2779 td->td_flags = (td->td_flags & ~cflags) | prev; 2780 thread_unlock(td); 2781 } 2782 } 2783 2784 /* 2785 * If the current process has received a signal (should be caught or cause 2786 * termination, should interrupt current syscall), return the signal number. 2787 * Stop signals with default action are processed immediately, then cleared; 2788 * they aren't returned. This is checked after each entry to the system for 2789 * a syscall or trap (though this can usually be done without calling issignal 2790 * by checking the pending signal masks in cursig.) The normal call 2791 * sequence is 2792 * 2793 * while (sig = cursig(curthread)) 2794 * postsig(sig); 2795 */ 2796 static int 2797 issignal(struct thread *td) 2798 { 2799 struct proc *p; 2800 struct sigacts *ps; 2801 struct sigqueue *queue; 2802 sigset_t sigpending; 2803 int sig, prop; 2804 2805 p = td->td_proc; 2806 ps = p->p_sigacts; 2807 mtx_assert(&ps->ps_mtx, MA_OWNED); 2808 PROC_LOCK_ASSERT(p, MA_OWNED); 2809 for (;;) { 2810 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 2811 2812 sigpending = td->td_sigqueue.sq_signals; 2813 SIGSETOR(sigpending, p->p_sigqueue.sq_signals); 2814 SIGSETNAND(sigpending, td->td_sigmask); 2815 2816 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags & 2817 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2818 SIG_STOPSIGMASK(sigpending); 2819 if (SIGISEMPTY(sigpending)) /* no signal to send */ 2820 return (0); 2821 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED && 2822 (p->p_flag2 & P2_PTRACE_FSTP) != 0 && 2823 SIGISMEMBER(sigpending, SIGSTOP)) { 2824 /* 2825 * If debugger just attached, always consume 2826 * SIGSTOP from ptrace(PT_ATTACH) first, to 2827 * execute the debugger attach ritual in 2828 * order. 2829 */ 2830 sig = SIGSTOP; 2831 td->td_dbgflags |= TDB_FSTP; 2832 } else { 2833 sig = sig_ffs(&sigpending); 2834 } 2835 2836 if (p->p_stops & S_SIG) { 2837 mtx_unlock(&ps->ps_mtx); 2838 stopevent(p, S_SIG, sig); 2839 mtx_lock(&ps->ps_mtx); 2840 } 2841 2842 /* 2843 * We should see pending but ignored signals 2844 * only if P_TRACED was on when they were posted. 2845 */ 2846 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) { 2847 sigqueue_delete(&td->td_sigqueue, sig); 2848 sigqueue_delete(&p->p_sigqueue, sig); 2849 continue; 2850 } 2851 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) { 2852 /* 2853 * If traced, always stop. 2854 * Remove old signal from queue before the stop. 2855 * XXX shrug off debugger, it causes siginfo to 2856 * be thrown away. 2857 */ 2858 queue = &td->td_sigqueue; 2859 td->td_dbgksi.ksi_signo = 0; 2860 if (sigqueue_get(queue, sig, &td->td_dbgksi) == 0) { 2861 queue = &p->p_sigqueue; 2862 sigqueue_get(queue, sig, &td->td_dbgksi); 2863 } 2864 2865 mtx_unlock(&ps->ps_mtx); 2866 sig = ptracestop(td, sig, &td->td_dbgksi); 2867 mtx_lock(&ps->ps_mtx); 2868 2869 /* 2870 * Keep looking if the debugger discarded the signal 2871 * or replaced it with a masked signal. 2872 * 2873 * If the traced bit got turned off, go back up 2874 * to the top to rescan signals. This ensures 2875 * that p_sig* and p_sigact are consistent. 2876 */ 2877 if (sig == 0 || (p->p_flag & P_TRACED) == 0) 2878 continue; 2879 } 2880 2881 prop = sigprop(sig); 2882 2883 /* 2884 * Decide whether the signal should be returned. 2885 * Return the signal's number, or fall through 2886 * to clear it from the pending mask. 2887 */ 2888 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2889 2890 case (intptr_t)SIG_DFL: 2891 /* 2892 * Don't take default actions on system processes. 2893 */ 2894 if (p->p_pid <= 1) { 2895 #ifdef DIAGNOSTIC 2896 /* 2897 * Are you sure you want to ignore SIGSEGV 2898 * in init? XXX 2899 */ 2900 printf("Process (pid %lu) got signal %d\n", 2901 (u_long)p->p_pid, sig); 2902 #endif 2903 break; /* == ignore */ 2904 } 2905 /* 2906 * If there is a pending stop signal to process with 2907 * default action, stop here, then clear the signal. 2908 * Traced or exiting processes should ignore stops. 2909 * Additionally, a member of an orphaned process group 2910 * should ignore tty stops. 2911 */ 2912 if (prop & SA_STOP) { 2913 if (p->p_flag & 2914 (P_TRACED | P_WEXIT | P_SINGLE_EXIT) || 2915 (p->p_pgrp->pg_jobc == 0 && 2916 prop & SA_TTYSTOP)) 2917 break; /* == ignore */ 2918 if (TD_SBDRY_INTR(td)) { 2919 KASSERT((td->td_flags & TDF_SBDRY) != 0, 2920 ("lost TDF_SBDRY")); 2921 return (-1); 2922 } 2923 mtx_unlock(&ps->ps_mtx); 2924 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2925 &p->p_mtx.lock_object, "Catching SIGSTOP"); 2926 sigqueue_delete(&td->td_sigqueue, sig); 2927 sigqueue_delete(&p->p_sigqueue, sig); 2928 p->p_flag |= P_STOPPED_SIG; 2929 p->p_xsig = sig; 2930 PROC_SLOCK(p); 2931 sig_suspend_threads(td, p, 0); 2932 thread_suspend_switch(td, p); 2933 PROC_SUNLOCK(p); 2934 mtx_lock(&ps->ps_mtx); 2935 goto next; 2936 } else if (prop & SA_IGNORE) { 2937 /* 2938 * Except for SIGCONT, shouldn't get here. 2939 * Default action is to ignore; drop it. 2940 */ 2941 break; /* == ignore */ 2942 } else 2943 return (sig); 2944 /*NOTREACHED*/ 2945 2946 case (intptr_t)SIG_IGN: 2947 /* 2948 * Masking above should prevent us ever trying 2949 * to take action on an ignored signal other 2950 * than SIGCONT, unless process is traced. 2951 */ 2952 if ((prop & SA_CONT) == 0 && 2953 (p->p_flag & P_TRACED) == 0) 2954 printf("issignal\n"); 2955 break; /* == ignore */ 2956 2957 default: 2958 /* 2959 * This signal has an action, let 2960 * postsig() process it. 2961 */ 2962 return (sig); 2963 } 2964 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */ 2965 sigqueue_delete(&p->p_sigqueue, sig); 2966 next:; 2967 } 2968 /* NOTREACHED */ 2969 } 2970 2971 void 2972 thread_stopped(struct proc *p) 2973 { 2974 int n; 2975 2976 PROC_LOCK_ASSERT(p, MA_OWNED); 2977 PROC_SLOCK_ASSERT(p, MA_OWNED); 2978 n = p->p_suspcount; 2979 if (p == curproc) 2980 n++; 2981 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) { 2982 PROC_SUNLOCK(p); 2983 p->p_flag &= ~P_WAITED; 2984 PROC_LOCK(p->p_pptr); 2985 childproc_stopped(p, (p->p_flag & P_TRACED) ? 2986 CLD_TRAPPED : CLD_STOPPED); 2987 PROC_UNLOCK(p->p_pptr); 2988 PROC_SLOCK(p); 2989 } 2990 } 2991 2992 /* 2993 * Take the action for the specified signal 2994 * from the current set of pending signals. 2995 */ 2996 int 2997 postsig(sig) 2998 register int sig; 2999 { 3000 struct thread *td = curthread; 3001 register struct proc *p = td->td_proc; 3002 struct sigacts *ps; 3003 sig_t action; 3004 ksiginfo_t ksi; 3005 sigset_t returnmask; 3006 3007 KASSERT(sig != 0, ("postsig")); 3008 3009 PROC_LOCK_ASSERT(p, MA_OWNED); 3010 ps = p->p_sigacts; 3011 mtx_assert(&ps->ps_mtx, MA_OWNED); 3012 ksiginfo_init(&ksi); 3013 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 && 3014 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0) 3015 return (0); 3016 ksi.ksi_signo = sig; 3017 if (ksi.ksi_code == SI_TIMER) 3018 itimer_accept(p, ksi.ksi_timerid, &ksi); 3019 action = ps->ps_sigact[_SIG_IDX(sig)]; 3020 #ifdef KTRACE 3021 if (KTRPOINT(td, KTR_PSIG)) 3022 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ? 3023 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code); 3024 #endif 3025 if (p->p_stops & S_SIG) { 3026 mtx_unlock(&ps->ps_mtx); 3027 stopevent(p, S_SIG, sig); 3028 mtx_lock(&ps->ps_mtx); 3029 } 3030 3031 if (action == SIG_DFL) { 3032 /* 3033 * Default action, where the default is to kill 3034 * the process. (Other cases were ignored above.) 3035 */ 3036 mtx_unlock(&ps->ps_mtx); 3037 sigexit(td, sig); 3038 /* NOTREACHED */ 3039 } else { 3040 /* 3041 * If we get here, the signal must be caught. 3042 */ 3043 KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig), 3044 ("postsig action")); 3045 /* 3046 * Set the new mask value and also defer further 3047 * occurrences of this signal. 3048 * 3049 * Special case: user has done a sigsuspend. Here the 3050 * current mask is not of interest, but rather the 3051 * mask from before the sigsuspend is what we want 3052 * restored after the signal processing is completed. 3053 */ 3054 if (td->td_pflags & TDP_OLDMASK) { 3055 returnmask = td->td_oldsigmask; 3056 td->td_pflags &= ~TDP_OLDMASK; 3057 } else 3058 returnmask = td->td_sigmask; 3059 3060 if (p->p_sig == sig) { 3061 p->p_code = 0; 3062 p->p_sig = 0; 3063 } 3064 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask); 3065 postsig_done(sig, td, ps); 3066 } 3067 return (1); 3068 } 3069 3070 /* 3071 * Kill the current process for stated reason. 3072 */ 3073 void 3074 killproc(p, why) 3075 struct proc *p; 3076 char *why; 3077 { 3078 3079 PROC_LOCK_ASSERT(p, MA_OWNED); 3080 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid, 3081 p->p_comm); 3082 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, 3083 p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why); 3084 p->p_flag |= P_WKILLED; 3085 kern_psignal(p, SIGKILL); 3086 } 3087 3088 /* 3089 * Force the current process to exit with the specified signal, dumping core 3090 * if appropriate. We bypass the normal tests for masked and caught signals, 3091 * allowing unrecoverable failures to terminate the process without changing 3092 * signal state. Mark the accounting record with the signal termination. 3093 * If dumping core, save the signal number for the debugger. Calls exit and 3094 * does not return. 3095 */ 3096 void 3097 sigexit(td, sig) 3098 struct thread *td; 3099 int sig; 3100 { 3101 struct proc *p = td->td_proc; 3102 3103 PROC_LOCK_ASSERT(p, MA_OWNED); 3104 p->p_acflag |= AXSIG; 3105 /* 3106 * We must be single-threading to generate a core dump. This 3107 * ensures that the registers in the core file are up-to-date. 3108 * Also, the ELF dump handler assumes that the thread list doesn't 3109 * change out from under it. 3110 * 3111 * XXX If another thread attempts to single-thread before us 3112 * (e.g. via fork()), we won't get a dump at all. 3113 */ 3114 if ((sigprop(sig) & SA_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) { 3115 p->p_sig = sig; 3116 /* 3117 * Log signals which would cause core dumps 3118 * (Log as LOG_INFO to appease those who don't want 3119 * these messages.) 3120 * XXX : Todo, as well as euid, write out ruid too 3121 * Note that coredump() drops proc lock. 3122 */ 3123 if (coredump(td) == 0) 3124 sig |= WCOREFLAG; 3125 if (kern_logsigexit) 3126 log(LOG_INFO, 3127 "pid %d (%s), uid %d: exited on signal %d%s\n", 3128 p->p_pid, p->p_comm, 3129 td->td_ucred ? td->td_ucred->cr_uid : -1, 3130 sig &~ WCOREFLAG, 3131 sig & WCOREFLAG ? " (core dumped)" : ""); 3132 } else 3133 PROC_UNLOCK(p); 3134 exit1(td, 0, sig); 3135 /* NOTREACHED */ 3136 } 3137 3138 /* 3139 * Send queued SIGCHLD to parent when child process's state 3140 * is changed. 3141 */ 3142 static void 3143 sigparent(struct proc *p, int reason, int status) 3144 { 3145 PROC_LOCK_ASSERT(p, MA_OWNED); 3146 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3147 3148 if (p->p_ksi != NULL) { 3149 p->p_ksi->ksi_signo = SIGCHLD; 3150 p->p_ksi->ksi_code = reason; 3151 p->p_ksi->ksi_status = status; 3152 p->p_ksi->ksi_pid = p->p_pid; 3153 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid; 3154 if (KSI_ONQ(p->p_ksi)) 3155 return; 3156 } 3157 pksignal(p->p_pptr, SIGCHLD, p->p_ksi); 3158 } 3159 3160 static void 3161 childproc_jobstate(struct proc *p, int reason, int sig) 3162 { 3163 struct sigacts *ps; 3164 3165 PROC_LOCK_ASSERT(p, MA_OWNED); 3166 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3167 3168 /* 3169 * Wake up parent sleeping in kern_wait(), also send 3170 * SIGCHLD to parent, but SIGCHLD does not guarantee 3171 * that parent will awake, because parent may masked 3172 * the signal. 3173 */ 3174 p->p_pptr->p_flag |= P_STATCHILD; 3175 wakeup(p->p_pptr); 3176 3177 ps = p->p_pptr->p_sigacts; 3178 mtx_lock(&ps->ps_mtx); 3179 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) { 3180 mtx_unlock(&ps->ps_mtx); 3181 sigparent(p, reason, sig); 3182 } else 3183 mtx_unlock(&ps->ps_mtx); 3184 } 3185 3186 void 3187 childproc_stopped(struct proc *p, int reason) 3188 { 3189 3190 childproc_jobstate(p, reason, p->p_xsig); 3191 } 3192 3193 void 3194 childproc_continued(struct proc *p) 3195 { 3196 childproc_jobstate(p, CLD_CONTINUED, SIGCONT); 3197 } 3198 3199 void 3200 childproc_exited(struct proc *p) 3201 { 3202 int reason, status; 3203 3204 if (WCOREDUMP(p->p_xsig)) { 3205 reason = CLD_DUMPED; 3206 status = WTERMSIG(p->p_xsig); 3207 } else if (WIFSIGNALED(p->p_xsig)) { 3208 reason = CLD_KILLED; 3209 status = WTERMSIG(p->p_xsig); 3210 } else { 3211 reason = CLD_EXITED; 3212 status = p->p_xexit; 3213 } 3214 /* 3215 * XXX avoid calling wakeup(p->p_pptr), the work is 3216 * done in exit1(). 3217 */ 3218 sigparent(p, reason, status); 3219 } 3220 3221 /* 3222 * We only have 1 character for the core count in the format 3223 * string, so the range will be 0-9 3224 */ 3225 #define MAX_NUM_CORES 10 3226 static int num_cores = 5; 3227 3228 static int 3229 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS) 3230 { 3231 int error; 3232 int new_val; 3233 3234 new_val = num_cores; 3235 error = sysctl_handle_int(oidp, &new_val, 0, req); 3236 if (error != 0 || req->newptr == NULL) 3237 return (error); 3238 if (new_val > MAX_NUM_CORES) 3239 new_val = MAX_NUM_CORES; 3240 if (new_val < 0) 3241 new_val = 0; 3242 num_cores = new_val; 3243 return (0); 3244 } 3245 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW, 3246 0, sizeof(int), sysctl_debug_num_cores_check, "I", ""); 3247 3248 #define GZ_SUFFIX ".gz" 3249 3250 #ifdef GZIO 3251 static int compress_user_cores = 1; 3252 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RWTUN, 3253 &compress_user_cores, 0, "Compression of user corefiles"); 3254 3255 int compress_user_cores_gzlevel = 6; 3256 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RWTUN, 3257 &compress_user_cores_gzlevel, 0, "Corefile gzip compression level"); 3258 #else 3259 static int compress_user_cores = 0; 3260 #endif 3261 3262 /* 3263 * Protect the access to corefilename[] by allproc_lock. 3264 */ 3265 #define corefilename_lock allproc_lock 3266 3267 static char corefilename[MAXPATHLEN] = {"%N.core"}; 3268 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename)); 3269 3270 static int 3271 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS) 3272 { 3273 int error; 3274 3275 sx_xlock(&corefilename_lock); 3276 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename), 3277 req); 3278 sx_xunlock(&corefilename_lock); 3279 3280 return (error); 3281 } 3282 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW | 3283 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", 3284 "Process corefile name format string"); 3285 3286 /* 3287 * corefile_open(comm, uid, pid, td, compress, vpp, namep) 3288 * Expand the name described in corefilename, using name, uid, and pid 3289 * and open/create core file. 3290 * corefilename is a printf-like string, with three format specifiers: 3291 * %N name of process ("name") 3292 * %P process id (pid) 3293 * %U user id (uid) 3294 * For example, "%N.core" is the default; they can be disabled completely 3295 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 3296 * This is controlled by the sysctl variable kern.corefile (see above). 3297 */ 3298 static int 3299 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, 3300 int compress, struct vnode **vpp, char **namep) 3301 { 3302 struct nameidata nd; 3303 struct sbuf sb; 3304 const char *format; 3305 char *hostname, *name; 3306 int indexpos, i, error, cmode, flags, oflags; 3307 3308 hostname = NULL; 3309 format = corefilename; 3310 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO); 3311 indexpos = -1; 3312 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN); 3313 sx_slock(&corefilename_lock); 3314 for (i = 0; format[i] != '\0'; i++) { 3315 switch (format[i]) { 3316 case '%': /* Format character */ 3317 i++; 3318 switch (format[i]) { 3319 case '%': 3320 sbuf_putc(&sb, '%'); 3321 break; 3322 case 'H': /* hostname */ 3323 if (hostname == NULL) { 3324 hostname = malloc(MAXHOSTNAMELEN, 3325 M_TEMP, M_WAITOK); 3326 } 3327 getcredhostname(td->td_ucred, hostname, 3328 MAXHOSTNAMELEN); 3329 sbuf_printf(&sb, "%s", hostname); 3330 break; 3331 case 'I': /* autoincrementing index */ 3332 sbuf_printf(&sb, ""); 3333 indexpos = sbuf_len(&sb) - 1; 3334 break; 3335 case 'N': /* process name */ 3336 sbuf_printf(&sb, "%s", comm); 3337 break; 3338 case 'P': /* process id */ 3339 sbuf_printf(&sb, "%u", pid); 3340 break; 3341 case 'U': /* user id */ 3342 sbuf_printf(&sb, "%u", uid); 3343 break; 3344 default: 3345 log(LOG_ERR, 3346 "Unknown format character %c in " 3347 "corename `%s'\n", format[i], format); 3348 break; 3349 } 3350 break; 3351 default: 3352 sbuf_putc(&sb, format[i]); 3353 break; 3354 } 3355 } 3356 sx_sunlock(&corefilename_lock); 3357 free(hostname, M_TEMP); 3358 if (compress) 3359 sbuf_printf(&sb, GZ_SUFFIX); 3360 if (sbuf_error(&sb) != 0) { 3361 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too " 3362 "long\n", (long)pid, comm, (u_long)uid); 3363 sbuf_delete(&sb); 3364 free(name, M_TEMP); 3365 return (ENOMEM); 3366 } 3367 sbuf_finish(&sb); 3368 sbuf_delete(&sb); 3369 3370 cmode = S_IRUSR | S_IWUSR; 3371 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3372 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3373 3374 /* 3375 * If the core format has a %I in it, then we need to check 3376 * for existing corefiles before returning a name. 3377 * To do this we iterate over 0..num_cores to find a 3378 * non-existing core file name to use. 3379 */ 3380 if (indexpos != -1) { 3381 for (i = 0; i < num_cores; i++) { 3382 flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW; 3383 name[indexpos] = '' + i; 3384 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3385 error = vn_open_cred(&nd, &flags, cmode, oflags, 3386 td->td_ucred, NULL); 3387 if (error) { 3388 if (error == EEXIST) 3389 continue; 3390 log(LOG_ERR, 3391 "pid %d (%s), uid (%u): Path `%s' failed " 3392 "on initial open test, error = %d\n", 3393 pid, comm, uid, name, error); 3394 } 3395 goto out; 3396 } 3397 } 3398 3399 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3400 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); 3401 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL); 3402 out: 3403 if (error) { 3404 #ifdef AUDIT 3405 audit_proc_coredump(td, name, error); 3406 #endif 3407 free(name, M_TEMP); 3408 return (error); 3409 } 3410 NDFREE(&nd, NDF_ONLY_PNBUF); 3411 *vpp = nd.ni_vp; 3412 *namep = name; 3413 return (0); 3414 } 3415 3416 static int 3417 coredump_sanitise_path(const char *path) 3418 { 3419 size_t i; 3420 3421 /* 3422 * Only send a subset of ASCII to devd(8) because it 3423 * might pass these strings to sh -c. 3424 */ 3425 for (i = 0; path[i]; i++) 3426 if (!(isalpha(path[i]) || isdigit(path[i])) && 3427 path[i] != '/' && path[i] != '.' && 3428 path[i] != '-') 3429 return (0); 3430 3431 return (1); 3432 } 3433 3434 /* 3435 * Dump a process' core. The main routine does some 3436 * policy checking, and creates the name of the coredump; 3437 * then it passes on a vnode and a size limit to the process-specific 3438 * coredump routine if there is one; if there _is not_ one, it returns 3439 * ENOSYS; otherwise it returns the error from the process-specific routine. 3440 */ 3441 3442 static int 3443 coredump(struct thread *td) 3444 { 3445 struct proc *p = td->td_proc; 3446 struct ucred *cred = td->td_ucred; 3447 struct vnode *vp; 3448 struct flock lf; 3449 struct vattr vattr; 3450 int error, error1, locked; 3451 char *name; /* name of corefile */ 3452 void *rl_cookie; 3453 off_t limit; 3454 char *data = NULL; 3455 char *fullpath, *freepath = NULL; 3456 size_t len; 3457 static const char comm_name[] = "comm="; 3458 static const char core_name[] = "core="; 3459 3460 PROC_LOCK_ASSERT(p, MA_OWNED); 3461 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td); 3462 _STOPEVENT(p, S_CORE, 0); 3463 3464 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) || 3465 (p->p_flag2 & P2_NOTRACE) != 0) { 3466 PROC_UNLOCK(p); 3467 return (EFAULT); 3468 } 3469 3470 /* 3471 * Note that the bulk of limit checking is done after 3472 * the corefile is created. The exception is if the limit 3473 * for corefiles is 0, in which case we don't bother 3474 * creating the corefile at all. This layout means that 3475 * a corefile is truncated instead of not being created, 3476 * if it is larger than the limit. 3477 */ 3478 limit = (off_t)lim_cur(td, RLIMIT_CORE); 3479 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) { 3480 PROC_UNLOCK(p); 3481 return (EFBIG); 3482 } 3483 PROC_UNLOCK(p); 3484 3485 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, 3486 compress_user_cores, &vp, &name); 3487 if (error != 0) 3488 return (error); 3489 3490 /* 3491 * Don't dump to non-regular files or files with links. 3492 * Do not dump into system files. 3493 */ 3494 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 || 3495 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0) { 3496 VOP_UNLOCK(vp, 0); 3497 error = EFAULT; 3498 goto out; 3499 } 3500 3501 VOP_UNLOCK(vp, 0); 3502 3503 /* Postpone other writers, including core dumps of other processes. */ 3504 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 3505 3506 lf.l_whence = SEEK_SET; 3507 lf.l_start = 0; 3508 lf.l_len = 0; 3509 lf.l_type = F_WRLCK; 3510 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0); 3511 3512 VATTR_NULL(&vattr); 3513 vattr.va_size = 0; 3514 if (set_core_nodump_flag) 3515 vattr.va_flags = UF_NODUMP; 3516 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 3517 VOP_SETATTR(vp, &vattr, cred); 3518 VOP_UNLOCK(vp, 0); 3519 PROC_LOCK(p); 3520 p->p_acflag |= ACORE; 3521 PROC_UNLOCK(p); 3522 3523 if (p->p_sysent->sv_coredump != NULL) { 3524 error = p->p_sysent->sv_coredump(td, vp, limit, 3525 compress_user_cores ? IMGACT_CORE_COMPRESS : 0); 3526 } else { 3527 error = ENOSYS; 3528 } 3529 3530 if (locked) { 3531 lf.l_type = F_UNLCK; 3532 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 3533 } 3534 vn_rangelock_unlock(vp, rl_cookie); 3535 3536 /* 3537 * Notify the userland helper that a process triggered a core dump. 3538 * This allows the helper to run an automated debugging session. 3539 */ 3540 if (error != 0 || coredump_devctl == 0) 3541 goto out; 3542 len = MAXPATHLEN * 2 + sizeof(comm_name) - 1 + 3543 sizeof(' ') + sizeof(core_name) - 1; 3544 data = malloc(len, M_TEMP, M_WAITOK); 3545 if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0) 3546 goto out; 3547 if (!coredump_sanitise_path(fullpath)) 3548 goto out; 3549 snprintf(data, len, "%s%s ", comm_name, fullpath); 3550 free(freepath, M_TEMP); 3551 freepath = NULL; 3552 if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0) 3553 goto out; 3554 if (!coredump_sanitise_path(fullpath)) 3555 goto out; 3556 strlcat(data, core_name, len); 3557 strlcat(data, fullpath, len); 3558 devctl_notify("kernel", "signal", "coredump", data); 3559 out: 3560 error1 = vn_close(vp, FWRITE, cred, td); 3561 if (error == 0) 3562 error = error1; 3563 #ifdef AUDIT 3564 audit_proc_coredump(td, name, error); 3565 #endif 3566 free(freepath, M_TEMP); 3567 free(data, M_TEMP); 3568 free(name, M_TEMP); 3569 return (error); 3570 } 3571 3572 /* 3573 * Nonexistent system call-- signal process (may want to handle it). Flag 3574 * error in case process won't see signal immediately (blocked or ignored). 3575 */ 3576 #ifndef _SYS_SYSPROTO_H_ 3577 struct nosys_args { 3578 int dummy; 3579 }; 3580 #endif 3581 /* ARGSUSED */ 3582 int 3583 nosys(td, args) 3584 struct thread *td; 3585 struct nosys_args *args; 3586 { 3587 struct proc *p = td->td_proc; 3588 3589 PROC_LOCK(p); 3590 tdsignal(td, SIGSYS); 3591 PROC_UNLOCK(p); 3592 return (ENOSYS); 3593 } 3594 3595 /* 3596 * Send a SIGIO or SIGURG signal to a process or process group using stored 3597 * credentials rather than those of the current process. 3598 */ 3599 void 3600 pgsigio(sigiop, sig, checkctty) 3601 struct sigio **sigiop; 3602 int sig, checkctty; 3603 { 3604 ksiginfo_t ksi; 3605 struct sigio *sigio; 3606 3607 ksiginfo_init(&ksi); 3608 ksi.ksi_signo = sig; 3609 ksi.ksi_code = SI_KERNEL; 3610 3611 SIGIO_LOCK(); 3612 sigio = *sigiop; 3613 if (sigio == NULL) { 3614 SIGIO_UNLOCK(); 3615 return; 3616 } 3617 if (sigio->sio_pgid > 0) { 3618 PROC_LOCK(sigio->sio_proc); 3619 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred)) 3620 kern_psignal(sigio->sio_proc, sig); 3621 PROC_UNLOCK(sigio->sio_proc); 3622 } else if (sigio->sio_pgid < 0) { 3623 struct proc *p; 3624 3625 PGRP_LOCK(sigio->sio_pgrp); 3626 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 3627 PROC_LOCK(p); 3628 if (p->p_state == PRS_NORMAL && 3629 CANSIGIO(sigio->sio_ucred, p->p_ucred) && 3630 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 3631 kern_psignal(p, sig); 3632 PROC_UNLOCK(p); 3633 } 3634 PGRP_UNLOCK(sigio->sio_pgrp); 3635 } 3636 SIGIO_UNLOCK(); 3637 } 3638 3639 static int 3640 filt_sigattach(struct knote *kn) 3641 { 3642 struct proc *p = curproc; 3643 3644 kn->kn_ptr.p_proc = p; 3645 kn->kn_flags |= EV_CLEAR; /* automatically set */ 3646 3647 knlist_add(p->p_klist, kn, 0); 3648 3649 return (0); 3650 } 3651 3652 static void 3653 filt_sigdetach(struct knote *kn) 3654 { 3655 struct proc *p = kn->kn_ptr.p_proc; 3656 3657 knlist_remove(p->p_klist, kn, 0); 3658 } 3659 3660 /* 3661 * signal knotes are shared with proc knotes, so we apply a mask to 3662 * the hint in order to differentiate them from process hints. This 3663 * could be avoided by using a signal-specific knote list, but probably 3664 * isn't worth the trouble. 3665 */ 3666 static int 3667 filt_signal(struct knote *kn, long hint) 3668 { 3669 3670 if (hint & NOTE_SIGNAL) { 3671 hint &= ~NOTE_SIGNAL; 3672 3673 if (kn->kn_id == hint) 3674 kn->kn_data++; 3675 } 3676 return (kn->kn_data != 0); 3677 } 3678 3679 struct sigacts * 3680 sigacts_alloc(void) 3681 { 3682 struct sigacts *ps; 3683 3684 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO); 3685 refcount_init(&ps->ps_refcnt, 1); 3686 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF); 3687 return (ps); 3688 } 3689 3690 void 3691 sigacts_free(struct sigacts *ps) 3692 { 3693 3694 if (refcount_release(&ps->ps_refcnt) == 0) 3695 return; 3696 mtx_destroy(&ps->ps_mtx); 3697 free(ps, M_SUBPROC); 3698 } 3699 3700 struct sigacts * 3701 sigacts_hold(struct sigacts *ps) 3702 { 3703 3704 refcount_acquire(&ps->ps_refcnt); 3705 return (ps); 3706 } 3707 3708 void 3709 sigacts_copy(struct sigacts *dest, struct sigacts *src) 3710 { 3711 3712 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest")); 3713 mtx_lock(&src->ps_mtx); 3714 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt)); 3715 mtx_unlock(&src->ps_mtx); 3716 } 3717 3718 int 3719 sigacts_shared(struct sigacts *ps) 3720 { 3721 3722 return (ps->ps_refcnt > 1); 3723 }
Cache object: cf22f54f0d5a1c0146de0ffbd80c6523
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