1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include "opt_capsicum.h" 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/capsicum.h> 42 #include <sys/ctype.h> 43 #include <sys/systm.h> 44 #include <sys/signalvar.h> 45 #include <sys/vnode.h> 46 #include <sys/acct.h> 47 #include <sys/capsicum.h> 48 #include <sys/compressor.h> 49 #include <sys/condvar.h> 50 #include <sys/devctl.h> 51 #include <sys/event.h> 52 #include <sys/fcntl.h> 53 #include <sys/imgact.h> 54 #include <sys/jail.h> 55 #include <sys/kernel.h> 56 #include <sys/ktr.h> 57 #include <sys/ktrace.h> 58 #include <sys/limits.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/ptrace.h> 67 #include <sys/posix4.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/syscall.h> 77 #include <sys/syscallsubr.h> 78 #include <sys/sysctl.h> 79 #include <sys/sysent.h> 80 #include <sys/syslog.h> 81 #include <sys/sysproto.h> 82 #include <sys/timers.h> 83 #include <sys/unistd.h> 84 #include <sys/vmmeter.h> 85 #include <sys/wait.h> 86 #include <vm/vm.h> 87 #include <vm/vm_extern.h> 88 #include <vm/uma.h> 89 90 #include <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 void reschedule_signals(struct proc *p, sigset_t block, int flags); 109 static int sigprop(int sig); 110 static void tdsigwakeup(struct thread *, int, sig_t, int); 111 static void sig_suspend_threads(struct thread *, struct proc *); 112 static int filt_sigattach(struct knote *kn); 113 static void filt_sigdetach(struct knote *kn); 114 static int filt_signal(struct knote *kn, long hint); 115 static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock); 116 static void sigqueue_start(void); 117 static void sigfastblock_setpend(struct thread *td, bool resched); 118 119 static uma_zone_t ksiginfo_zone = NULL; 120 const struct filterops sig_filtops = { 121 .f_isfd = 0, 122 .f_attach = filt_sigattach, 123 .f_detach = filt_sigdetach, 124 .f_event = filt_signal, 125 }; 126 127 static int kern_logsigexit = 1; 128 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 129 &kern_logsigexit, 0, 130 "Log processes quitting on abnormal signals to syslog(3)"); 131 132 static int kern_forcesigexit = 1; 133 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW, 134 &kern_forcesigexit, 0, "Force trap signal to be handled"); 135 136 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 137 "POSIX real time signal"); 138 139 static int max_pending_per_proc = 128; 140 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW, 141 &max_pending_per_proc, 0, "Max pending signals per proc"); 142 143 static int preallocate_siginfo = 1024; 144 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN, 145 &preallocate_siginfo, 0, "Preallocated signal memory size"); 146 147 static int signal_overflow = 0; 148 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD, 149 &signal_overflow, 0, "Number of signals overflew"); 150 151 static int signal_alloc_fail = 0; 152 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD, 153 &signal_alloc_fail, 0, "signals failed to be allocated"); 154 155 static int kern_lognosys = 0; 156 SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0, 157 "Log invalid syscalls"); 158 159 static int kern_signosys = 1; 160 SYSCTL_INT(_kern, OID_AUTO, signosys, CTLFLAG_RWTUN, &kern_signosys, 0, 161 "Send SIGSYS on return from invalid syscall"); 162 163 __read_frequently bool sigfastblock_fetch_always = false; 164 SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN, 165 &sigfastblock_fetch_always, 0, 166 "Fetch sigfastblock word on each syscall entry for proper " 167 "blocking semantic"); 168 169 static bool kern_sig_discard_ign = true; 170 SYSCTL_BOOL(_kern, OID_AUTO, sig_discard_ign, CTLFLAG_RWTUN, 171 &kern_sig_discard_ign, 0, 172 "Discard ignored signals on delivery, otherwise queue them to " 173 "the target queue"); 174 175 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL); 176 177 /* 178 * Policy -- Can ucred cr1 send SIGIO to process cr2? 179 * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG 180 * in the right situations. 181 */ 182 #define CANSIGIO(cr1, cr2) \ 183 ((cr1)->cr_uid == 0 || \ 184 (cr1)->cr_ruid == (cr2)->cr_ruid || \ 185 (cr1)->cr_uid == (cr2)->cr_ruid || \ 186 (cr1)->cr_ruid == (cr2)->cr_uid || \ 187 (cr1)->cr_uid == (cr2)->cr_uid) 188 189 static int sugid_coredump; 190 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN, 191 &sugid_coredump, 0, "Allow setuid and setgid processes to dump core"); 192 193 static int capmode_coredump; 194 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN, 195 &capmode_coredump, 0, "Allow processes in capability mode to dump core"); 196 197 static int do_coredump = 1; 198 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 199 &do_coredump, 0, "Enable/Disable coredumps"); 200 201 static int set_core_nodump_flag = 0; 202 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag, 203 0, "Enable setting the NODUMP flag on coredump files"); 204 205 static int coredump_devctl = 0; 206 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl, 207 0, "Generate a devctl notification when processes coredump"); 208 209 /* 210 * Signal properties and actions. 211 * The array below categorizes the signals and their default actions 212 * according to the following properties: 213 */ 214 #define SIGPROP_KILL 0x01 /* terminates process by default */ 215 #define SIGPROP_CORE 0x02 /* ditto and coredumps */ 216 #define SIGPROP_STOP 0x04 /* suspend process */ 217 #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */ 218 #define SIGPROP_IGNORE 0x10 /* ignore by default */ 219 #define SIGPROP_CONT 0x20 /* continue if suspended */ 220 221 static const int sigproptbl[NSIG] = { 222 [SIGHUP] = SIGPROP_KILL, 223 [SIGINT] = SIGPROP_KILL, 224 [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE, 225 [SIGILL] = SIGPROP_KILL | SIGPROP_CORE, 226 [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE, 227 [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE, 228 [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE, 229 [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE, 230 [SIGKILL] = SIGPROP_KILL, 231 [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE, 232 [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE, 233 [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE, 234 [SIGPIPE] = SIGPROP_KILL, 235 [SIGALRM] = SIGPROP_KILL, 236 [SIGTERM] = SIGPROP_KILL, 237 [SIGURG] = SIGPROP_IGNORE, 238 [SIGSTOP] = SIGPROP_STOP, 239 [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP, 240 [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT, 241 [SIGCHLD] = SIGPROP_IGNORE, 242 [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP, 243 [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP, 244 [SIGIO] = SIGPROP_IGNORE, 245 [SIGXCPU] = SIGPROP_KILL, 246 [SIGXFSZ] = SIGPROP_KILL, 247 [SIGVTALRM] = SIGPROP_KILL, 248 [SIGPROF] = SIGPROP_KILL, 249 [SIGWINCH] = SIGPROP_IGNORE, 250 [SIGINFO] = SIGPROP_IGNORE, 251 [SIGUSR1] = SIGPROP_KILL, 252 [SIGUSR2] = SIGPROP_KILL, 253 }; 254 255 #define _SIG_FOREACH_ADVANCE(i, set) ({ \ 256 int __found; \ 257 for (;;) { \ 258 if (__bits != 0) { \ 259 int __sig = ffs(__bits); \ 260 __bits &= ~(1u << (__sig - 1)); \ 261 sig = __i * sizeof((set)->__bits[0]) * NBBY + __sig; \ 262 __found = 1; \ 263 break; \ 264 } \ 265 if (++__i == _SIG_WORDS) { \ 266 __found = 0; \ 267 break; \ 268 } \ 269 __bits = (set)->__bits[__i]; \ 270 } \ 271 __found != 0; \ 272 }) 273 274 #define SIG_FOREACH(i, set) \ 275 for (int32_t __i = -1, __bits = 0; \ 276 _SIG_FOREACH_ADVANCE(i, set); ) \ 277 278 static sigset_t fastblock_mask; 279 280 static void 281 ast_sig(struct thread *td, int tda) 282 { 283 struct proc *p; 284 int old_boundary, sig; 285 bool resched_sigs; 286 287 p = td->td_proc; 288 289 #ifdef DIAGNOSTIC 290 if (p->p_numthreads == 1 && (tda & (TDAI(TDA_SIG) | 291 TDAI(TDA_AST))) == 0) { 292 PROC_LOCK(p); 293 thread_lock(td); 294 /* 295 * Note that TDA_SIG should be re-read from 296 * td_ast, since signal might have been delivered 297 * after we cleared td_flags above. This is one of 298 * the reason for looping check for AST condition. 299 * See comment in userret() about P_PPWAIT. 300 */ 301 if ((p->p_flag & P_PPWAIT) == 0 && 302 (td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 303 if (SIGPENDING(td) && ((tda | td->td_ast) & 304 (TDAI(TDA_SIG) | TDAI(TDA_AST))) == 0) { 305 thread_unlock(td); /* fix dumps */ 306 panic( 307 "failed2 to set signal flags for ast p %p " 308 "td %p tda %#x td_ast %#x fl %#x", 309 p, td, tda, td->td_ast, td->td_flags); 310 } 311 } 312 thread_unlock(td); 313 PROC_UNLOCK(p); 314 } 315 #endif 316 317 /* 318 * Check for signals. Unlocked reads of p_pendingcnt or 319 * p_siglist might cause process-directed signal to be handled 320 * later. 321 */ 322 if ((tda & TDAI(TDA_SIG)) != 0 || p->p_pendingcnt > 0 || 323 !SIGISEMPTY(p->p_siglist)) { 324 sigfastblock_fetch(td); 325 PROC_LOCK(p); 326 old_boundary = ~TDB_BOUNDARY | (td->td_dbgflags & TDB_BOUNDARY); 327 td->td_dbgflags |= TDB_BOUNDARY; 328 mtx_lock(&p->p_sigacts->ps_mtx); 329 while ((sig = cursig(td)) != 0) { 330 KASSERT(sig >= 0, ("sig %d", sig)); 331 postsig(sig); 332 } 333 mtx_unlock(&p->p_sigacts->ps_mtx); 334 td->td_dbgflags &= old_boundary; 335 PROC_UNLOCK(p); 336 resched_sigs = true; 337 } else { 338 resched_sigs = false; 339 } 340 341 /* 342 * Handle deferred update of the fast sigblock value, after 343 * the postsig() loop was performed. 344 */ 345 sigfastblock_setpend(td, resched_sigs); 346 347 /* 348 * Clear td_sa.code: signal to ptrace that syscall arguments 349 * are unavailable after this point. This AST handler is the 350 * last chance for ptracestop() to signal the tracer before 351 * the tracee returns to userspace. 352 */ 353 td->td_sa.code = 0; 354 } 355 356 static void 357 ast_sigsuspend(struct thread *td, int tda __unused) 358 { 359 MPASS((td->td_pflags & TDP_OLDMASK) != 0); 360 td->td_pflags &= ~TDP_OLDMASK; 361 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0); 362 } 363 364 static void 365 sigqueue_start(void) 366 { 367 ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t), 368 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 369 uma_prealloc(ksiginfo_zone, preallocate_siginfo); 370 p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS); 371 p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1); 372 p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc); 373 SIGFILLSET(fastblock_mask); 374 SIG_CANTMASK(fastblock_mask); 375 ast_register(TDA_SIG, ASTR_UNCOND, 0, ast_sig); 376 377 /* 378 * TDA_PSELECT is for the case where the signal mask should be restored 379 * before delivering any signals so that we do not deliver any that are 380 * blocked by the normal thread mask. It is mutually exclusive with 381 * TDA_SIGSUSPEND, which should be used if we *do* want to deliver 382 * signals that are normally blocked, e.g., if it interrupted our sleep. 383 */ 384 ast_register(TDA_PSELECT, ASTR_ASTF_REQUIRED | ASTR_TDP, 385 TDP_OLDMASK, ast_sigsuspend); 386 ast_register(TDA_SIGSUSPEND, ASTR_ASTF_REQUIRED | ASTR_TDP, 387 TDP_OLDMASK, ast_sigsuspend); 388 } 389 390 ksiginfo_t * 391 ksiginfo_alloc(int mwait) 392 { 393 MPASS(mwait == M_WAITOK || mwait == M_NOWAIT); 394 395 if (ksiginfo_zone == NULL) 396 return (NULL); 397 return (uma_zalloc(ksiginfo_zone, mwait | M_ZERO)); 398 } 399 400 void 401 ksiginfo_free(ksiginfo_t *ksi) 402 { 403 uma_zfree(ksiginfo_zone, ksi); 404 } 405 406 static __inline bool 407 ksiginfo_tryfree(ksiginfo_t *ksi) 408 { 409 if ((ksi->ksi_flags & KSI_EXT) == 0) { 410 uma_zfree(ksiginfo_zone, ksi); 411 return (true); 412 } 413 return (false); 414 } 415 416 void 417 sigqueue_init(sigqueue_t *list, struct proc *p) 418 { 419 SIGEMPTYSET(list->sq_signals); 420 SIGEMPTYSET(list->sq_kill); 421 SIGEMPTYSET(list->sq_ptrace); 422 TAILQ_INIT(&list->sq_list); 423 list->sq_proc = p; 424 list->sq_flags = SQ_INIT; 425 } 426 427 /* 428 * Get a signal's ksiginfo. 429 * Return: 430 * 0 - signal not found 431 * others - signal number 432 */ 433 static int 434 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si) 435 { 436 struct proc *p = sq->sq_proc; 437 struct ksiginfo *ksi, *next; 438 int count = 0; 439 440 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 441 442 if (!SIGISMEMBER(sq->sq_signals, signo)) 443 return (0); 444 445 if (SIGISMEMBER(sq->sq_ptrace, signo)) { 446 count++; 447 SIGDELSET(sq->sq_ptrace, signo); 448 si->ksi_flags |= KSI_PTRACE; 449 } 450 if (SIGISMEMBER(sq->sq_kill, signo)) { 451 count++; 452 if (count == 1) 453 SIGDELSET(sq->sq_kill, signo); 454 } 455 456 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 457 if (ksi->ksi_signo == signo) { 458 if (count == 0) { 459 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 460 ksi->ksi_sigq = NULL; 461 ksiginfo_copy(ksi, si); 462 if (ksiginfo_tryfree(ksi) && p != NULL) 463 p->p_pendingcnt--; 464 } 465 if (++count > 1) 466 break; 467 } 468 } 469 470 if (count <= 1) 471 SIGDELSET(sq->sq_signals, signo); 472 si->ksi_signo = signo; 473 return (signo); 474 } 475 476 void 477 sigqueue_take(ksiginfo_t *ksi) 478 { 479 struct ksiginfo *kp; 480 struct proc *p; 481 sigqueue_t *sq; 482 483 if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL) 484 return; 485 486 p = sq->sq_proc; 487 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 488 ksi->ksi_sigq = NULL; 489 if (!(ksi->ksi_flags & KSI_EXT) && p != NULL) 490 p->p_pendingcnt--; 491 492 for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL; 493 kp = TAILQ_NEXT(kp, ksi_link)) { 494 if (kp->ksi_signo == ksi->ksi_signo) 495 break; 496 } 497 if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) && 498 !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo)) 499 SIGDELSET(sq->sq_signals, ksi->ksi_signo); 500 } 501 502 static int 503 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si) 504 { 505 struct proc *p = sq->sq_proc; 506 struct ksiginfo *ksi; 507 int ret = 0; 508 509 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 510 511 /* 512 * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path 513 * for these signals. 514 */ 515 if (signo == SIGKILL || signo == SIGSTOP || si == NULL) { 516 SIGADDSET(sq->sq_kill, signo); 517 goto out_set_bit; 518 } 519 520 /* directly insert the ksi, don't copy it */ 521 if (si->ksi_flags & KSI_INS) { 522 if (si->ksi_flags & KSI_HEAD) 523 TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link); 524 else 525 TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link); 526 si->ksi_sigq = sq; 527 goto out_set_bit; 528 } 529 530 if (__predict_false(ksiginfo_zone == NULL)) { 531 SIGADDSET(sq->sq_kill, signo); 532 goto out_set_bit; 533 } 534 535 if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) { 536 signal_overflow++; 537 ret = EAGAIN; 538 } else if ((ksi = ksiginfo_alloc(M_NOWAIT)) == NULL) { 539 signal_alloc_fail++; 540 ret = EAGAIN; 541 } else { 542 if (p != NULL) 543 p->p_pendingcnt++; 544 ksiginfo_copy(si, ksi); 545 ksi->ksi_signo = signo; 546 if (si->ksi_flags & KSI_HEAD) 547 TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link); 548 else 549 TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link); 550 ksi->ksi_sigq = sq; 551 } 552 553 if (ret != 0) { 554 if ((si->ksi_flags & KSI_PTRACE) != 0) { 555 SIGADDSET(sq->sq_ptrace, signo); 556 ret = 0; 557 goto out_set_bit; 558 } else if ((si->ksi_flags & KSI_TRAP) != 0 || 559 (si->ksi_flags & KSI_SIGQ) == 0) { 560 SIGADDSET(sq->sq_kill, signo); 561 ret = 0; 562 goto out_set_bit; 563 } 564 return (ret); 565 } 566 567 out_set_bit: 568 SIGADDSET(sq->sq_signals, signo); 569 return (ret); 570 } 571 572 void 573 sigqueue_flush(sigqueue_t *sq) 574 { 575 struct proc *p = sq->sq_proc; 576 ksiginfo_t *ksi; 577 578 KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); 579 580 if (p != NULL) 581 PROC_LOCK_ASSERT(p, MA_OWNED); 582 583 while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) { 584 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 585 ksi->ksi_sigq = NULL; 586 if (ksiginfo_tryfree(ksi) && p != NULL) 587 p->p_pendingcnt--; 588 } 589 590 SIGEMPTYSET(sq->sq_signals); 591 SIGEMPTYSET(sq->sq_kill); 592 SIGEMPTYSET(sq->sq_ptrace); 593 } 594 595 static void 596 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set) 597 { 598 sigset_t tmp; 599 struct proc *p1, *p2; 600 ksiginfo_t *ksi, *next; 601 602 KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited")); 603 KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited")); 604 p1 = src->sq_proc; 605 p2 = dst->sq_proc; 606 /* Move siginfo to target list */ 607 TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) { 608 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 609 TAILQ_REMOVE(&src->sq_list, ksi, ksi_link); 610 if (p1 != NULL) 611 p1->p_pendingcnt--; 612 TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link); 613 ksi->ksi_sigq = dst; 614 if (p2 != NULL) 615 p2->p_pendingcnt++; 616 } 617 } 618 619 /* Move pending bits to target list */ 620 tmp = src->sq_kill; 621 SIGSETAND(tmp, *set); 622 SIGSETOR(dst->sq_kill, tmp); 623 SIGSETNAND(src->sq_kill, tmp); 624 625 tmp = src->sq_ptrace; 626 SIGSETAND(tmp, *set); 627 SIGSETOR(dst->sq_ptrace, tmp); 628 SIGSETNAND(src->sq_ptrace, tmp); 629 630 tmp = src->sq_signals; 631 SIGSETAND(tmp, *set); 632 SIGSETOR(dst->sq_signals, tmp); 633 SIGSETNAND(src->sq_signals, tmp); 634 } 635 636 #if 0 637 static void 638 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo) 639 { 640 sigset_t set; 641 642 SIGEMPTYSET(set); 643 SIGADDSET(set, signo); 644 sigqueue_move_set(src, dst, &set); 645 } 646 #endif 647 648 static void 649 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set) 650 { 651 struct proc *p = sq->sq_proc; 652 ksiginfo_t *ksi, *next; 653 654 KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited")); 655 656 /* Remove siginfo queue */ 657 TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { 658 if (SIGISMEMBER(*set, ksi->ksi_signo)) { 659 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); 660 ksi->ksi_sigq = NULL; 661 if (ksiginfo_tryfree(ksi) && p != NULL) 662 p->p_pendingcnt--; 663 } 664 } 665 SIGSETNAND(sq->sq_kill, *set); 666 SIGSETNAND(sq->sq_ptrace, *set); 667 SIGSETNAND(sq->sq_signals, *set); 668 } 669 670 void 671 sigqueue_delete(sigqueue_t *sq, int signo) 672 { 673 sigset_t set; 674 675 SIGEMPTYSET(set); 676 SIGADDSET(set, signo); 677 sigqueue_delete_set(sq, &set); 678 } 679 680 /* Remove a set of signals for a process */ 681 static void 682 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set) 683 { 684 sigqueue_t worklist; 685 struct thread *td0; 686 687 PROC_LOCK_ASSERT(p, MA_OWNED); 688 689 sigqueue_init(&worklist, NULL); 690 sigqueue_move_set(&p->p_sigqueue, &worklist, set); 691 692 FOREACH_THREAD_IN_PROC(p, td0) 693 sigqueue_move_set(&td0->td_sigqueue, &worklist, set); 694 695 sigqueue_flush(&worklist); 696 } 697 698 void 699 sigqueue_delete_proc(struct proc *p, int signo) 700 { 701 sigset_t set; 702 703 SIGEMPTYSET(set); 704 SIGADDSET(set, signo); 705 sigqueue_delete_set_proc(p, &set); 706 } 707 708 static void 709 sigqueue_delete_stopmask_proc(struct proc *p) 710 { 711 sigset_t set; 712 713 SIGEMPTYSET(set); 714 SIGADDSET(set, SIGSTOP); 715 SIGADDSET(set, SIGTSTP); 716 SIGADDSET(set, SIGTTIN); 717 SIGADDSET(set, SIGTTOU); 718 sigqueue_delete_set_proc(p, &set); 719 } 720 721 /* 722 * Determine signal that should be delivered to thread td, the current 723 * thread, 0 if none. If there is a pending stop signal with default 724 * action, the process stops in issignal(). 725 */ 726 int 727 cursig(struct thread *td) 728 { 729 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 730 mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED); 731 THREAD_LOCK_ASSERT(td, MA_NOTOWNED); 732 return (SIGPENDING(td) ? issignal(td) : 0); 733 } 734 735 /* 736 * Arrange for ast() to handle unmasked pending signals on return to user 737 * mode. This must be called whenever a signal is added to td_sigqueue or 738 * unmasked in td_sigmask. 739 */ 740 void 741 signotify(struct thread *td) 742 { 743 744 PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); 745 746 if (SIGPENDING(td)) 747 ast_sched(td, TDA_SIG); 748 } 749 750 /* 751 * Returns 1 (true) if altstack is configured for the thread, and the 752 * passed stack bottom address falls into the altstack range. Handles 753 * the 43 compat special case where the alt stack size is zero. 754 */ 755 int 756 sigonstack(size_t sp) 757 { 758 struct thread *td; 759 760 td = curthread; 761 if ((td->td_pflags & TDP_ALTSTACK) == 0) 762 return (0); 763 #if defined(COMPAT_43) 764 if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0) 765 return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0); 766 #endif 767 return (sp >= (size_t)td->td_sigstk.ss_sp && 768 sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp); 769 } 770 771 static __inline int 772 sigprop(int sig) 773 { 774 775 if (sig > 0 && sig < nitems(sigproptbl)) 776 return (sigproptbl[sig]); 777 return (0); 778 } 779 780 static bool 781 sigact_flag_test(const struct sigaction *act, int flag) 782 { 783 784 /* 785 * SA_SIGINFO is reset when signal disposition is set to 786 * ignore or default. Other flags are kept according to user 787 * settings. 788 */ 789 return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO || 790 ((__sighandler_t *)act->sa_sigaction != SIG_IGN && 791 (__sighandler_t *)act->sa_sigaction != SIG_DFL))); 792 } 793 794 /* 795 * kern_sigaction 796 * sigaction 797 * freebsd4_sigaction 798 * osigaction 799 */ 800 int 801 kern_sigaction(struct thread *td, int sig, const struct sigaction *act, 802 struct sigaction *oact, int flags) 803 { 804 struct sigacts *ps; 805 struct proc *p = td->td_proc; 806 807 if (!_SIG_VALID(sig)) 808 return (EINVAL); 809 if (act != NULL && act->sa_handler != SIG_DFL && 810 act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK | 811 SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | 812 SA_NOCLDWAIT | SA_SIGINFO)) != 0) 813 return (EINVAL); 814 815 PROC_LOCK(p); 816 ps = p->p_sigacts; 817 mtx_lock(&ps->ps_mtx); 818 if (oact) { 819 memset(oact, 0, sizeof(*oact)); 820 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 821 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 822 oact->sa_flags |= SA_ONSTACK; 823 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 824 oact->sa_flags |= SA_RESTART; 825 if (SIGISMEMBER(ps->ps_sigreset, sig)) 826 oact->sa_flags |= SA_RESETHAND; 827 if (SIGISMEMBER(ps->ps_signodefer, sig)) 828 oact->sa_flags |= SA_NODEFER; 829 if (SIGISMEMBER(ps->ps_siginfo, sig)) { 830 oact->sa_flags |= SA_SIGINFO; 831 oact->sa_sigaction = 832 (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)]; 833 } else 834 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 835 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP) 836 oact->sa_flags |= SA_NOCLDSTOP; 837 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT) 838 oact->sa_flags |= SA_NOCLDWAIT; 839 } 840 if (act) { 841 if ((sig == SIGKILL || sig == SIGSTOP) && 842 act->sa_handler != SIG_DFL) { 843 mtx_unlock(&ps->ps_mtx); 844 PROC_UNLOCK(p); 845 return (EINVAL); 846 } 847 848 /* 849 * Change setting atomically. 850 */ 851 852 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 853 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 854 if (sigact_flag_test(act, SA_SIGINFO)) { 855 ps->ps_sigact[_SIG_IDX(sig)] = 856 (__sighandler_t *)act->sa_sigaction; 857 SIGADDSET(ps->ps_siginfo, sig); 858 } else { 859 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 860 SIGDELSET(ps->ps_siginfo, sig); 861 } 862 if (!sigact_flag_test(act, SA_RESTART)) 863 SIGADDSET(ps->ps_sigintr, sig); 864 else 865 SIGDELSET(ps->ps_sigintr, sig); 866 if (sigact_flag_test(act, SA_ONSTACK)) 867 SIGADDSET(ps->ps_sigonstack, sig); 868 else 869 SIGDELSET(ps->ps_sigonstack, sig); 870 if (sigact_flag_test(act, SA_RESETHAND)) 871 SIGADDSET(ps->ps_sigreset, sig); 872 else 873 SIGDELSET(ps->ps_sigreset, sig); 874 if (sigact_flag_test(act, SA_NODEFER)) 875 SIGADDSET(ps->ps_signodefer, sig); 876 else 877 SIGDELSET(ps->ps_signodefer, sig); 878 if (sig == SIGCHLD) { 879 if (act->sa_flags & SA_NOCLDSTOP) 880 ps->ps_flag |= PS_NOCLDSTOP; 881 else 882 ps->ps_flag &= ~PS_NOCLDSTOP; 883 if (act->sa_flags & SA_NOCLDWAIT) { 884 /* 885 * Paranoia: since SA_NOCLDWAIT is implemented 886 * by reparenting the dying child to PID 1 (and 887 * trust it to reap the zombie), PID 1 itself 888 * is forbidden to set SA_NOCLDWAIT. 889 */ 890 if (p->p_pid == 1) 891 ps->ps_flag &= ~PS_NOCLDWAIT; 892 else 893 ps->ps_flag |= PS_NOCLDWAIT; 894 } else 895 ps->ps_flag &= ~PS_NOCLDWAIT; 896 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 897 ps->ps_flag |= PS_CLDSIGIGN; 898 else 899 ps->ps_flag &= ~PS_CLDSIGIGN; 900 } 901 /* 902 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 903 * and for signals set to SIG_DFL where the default is to 904 * ignore. However, don't put SIGCONT in ps_sigignore, as we 905 * have to restart the process. 906 */ 907 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 908 (sigprop(sig) & SIGPROP_IGNORE && 909 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 910 /* never to be seen again */ 911 sigqueue_delete_proc(p, sig); 912 if (sig != SIGCONT) 913 /* easier in psignal */ 914 SIGADDSET(ps->ps_sigignore, sig); 915 SIGDELSET(ps->ps_sigcatch, sig); 916 } else { 917 SIGDELSET(ps->ps_sigignore, sig); 918 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 919 SIGDELSET(ps->ps_sigcatch, sig); 920 else 921 SIGADDSET(ps->ps_sigcatch, sig); 922 } 923 #ifdef COMPAT_FREEBSD4 924 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 925 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 926 (flags & KSA_FREEBSD4) == 0) 927 SIGDELSET(ps->ps_freebsd4, sig); 928 else 929 SIGADDSET(ps->ps_freebsd4, sig); 930 #endif 931 #ifdef COMPAT_43 932 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 933 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || 934 (flags & KSA_OSIGSET) == 0) 935 SIGDELSET(ps->ps_osigset, sig); 936 else 937 SIGADDSET(ps->ps_osigset, sig); 938 #endif 939 } 940 mtx_unlock(&ps->ps_mtx); 941 PROC_UNLOCK(p); 942 return (0); 943 } 944 945 #ifndef _SYS_SYSPROTO_H_ 946 struct sigaction_args { 947 int sig; 948 struct sigaction *act; 949 struct sigaction *oact; 950 }; 951 #endif 952 int 953 sys_sigaction(struct thread *td, struct sigaction_args *uap) 954 { 955 struct sigaction act, oact; 956 struct sigaction *actp, *oactp; 957 int error; 958 959 actp = (uap->act != NULL) ? &act : NULL; 960 oactp = (uap->oact != NULL) ? &oact : NULL; 961 if (actp) { 962 error = copyin(uap->act, actp, sizeof(act)); 963 if (error) 964 return (error); 965 } 966 error = kern_sigaction(td, uap->sig, actp, oactp, 0); 967 if (oactp && !error) 968 error = copyout(oactp, uap->oact, sizeof(oact)); 969 return (error); 970 } 971 972 #ifdef COMPAT_FREEBSD4 973 #ifndef _SYS_SYSPROTO_H_ 974 struct freebsd4_sigaction_args { 975 int sig; 976 struct sigaction *act; 977 struct sigaction *oact; 978 }; 979 #endif 980 int 981 freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap) 982 { 983 struct sigaction act, oact; 984 struct sigaction *actp, *oactp; 985 int error; 986 987 actp = (uap->act != NULL) ? &act : NULL; 988 oactp = (uap->oact != NULL) ? &oact : NULL; 989 if (actp) { 990 error = copyin(uap->act, actp, sizeof(act)); 991 if (error) 992 return (error); 993 } 994 error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4); 995 if (oactp && !error) 996 error = copyout(oactp, uap->oact, sizeof(oact)); 997 return (error); 998 } 999 #endif /* COMAPT_FREEBSD4 */ 1000 1001 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1002 #ifndef _SYS_SYSPROTO_H_ 1003 struct osigaction_args { 1004 int signum; 1005 struct osigaction *nsa; 1006 struct osigaction *osa; 1007 }; 1008 #endif 1009 int 1010 osigaction(struct thread *td, struct osigaction_args *uap) 1011 { 1012 struct osigaction sa; 1013 struct sigaction nsa, osa; 1014 struct sigaction *nsap, *osap; 1015 int error; 1016 1017 if (uap->signum <= 0 || uap->signum >= ONSIG) 1018 return (EINVAL); 1019 1020 nsap = (uap->nsa != NULL) ? &nsa : NULL; 1021 osap = (uap->osa != NULL) ? &osa : NULL; 1022 1023 if (nsap) { 1024 error = copyin(uap->nsa, &sa, sizeof(sa)); 1025 if (error) 1026 return (error); 1027 nsap->sa_handler = sa.sa_handler; 1028 nsap->sa_flags = sa.sa_flags; 1029 OSIG2SIG(sa.sa_mask, nsap->sa_mask); 1030 } 1031 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 1032 if (osap && !error) { 1033 sa.sa_handler = osap->sa_handler; 1034 sa.sa_flags = osap->sa_flags; 1035 SIG2OSIG(osap->sa_mask, sa.sa_mask); 1036 error = copyout(&sa, uap->osa, sizeof(sa)); 1037 } 1038 return (error); 1039 } 1040 1041 #if !defined(__i386__) 1042 /* Avoid replicating the same stub everywhere */ 1043 int 1044 osigreturn(struct thread *td, struct osigreturn_args *uap) 1045 { 1046 1047 return (nosys(td, (struct nosys_args *)uap)); 1048 } 1049 #endif 1050 #endif /* COMPAT_43 */ 1051 1052 /* 1053 * Initialize signal state for process 0; 1054 * set to ignore signals that are ignored by default. 1055 */ 1056 void 1057 siginit(struct proc *p) 1058 { 1059 int i; 1060 struct sigacts *ps; 1061 1062 PROC_LOCK(p); 1063 ps = p->p_sigacts; 1064 mtx_lock(&ps->ps_mtx); 1065 for (i = 1; i <= NSIG; i++) { 1066 if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) { 1067 SIGADDSET(ps->ps_sigignore, i); 1068 } 1069 } 1070 mtx_unlock(&ps->ps_mtx); 1071 PROC_UNLOCK(p); 1072 } 1073 1074 /* 1075 * Reset specified signal to the default disposition. 1076 */ 1077 static void 1078 sigdflt(struct sigacts *ps, int sig) 1079 { 1080 1081 mtx_assert(&ps->ps_mtx, MA_OWNED); 1082 SIGDELSET(ps->ps_sigcatch, sig); 1083 if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT) 1084 SIGADDSET(ps->ps_sigignore, sig); 1085 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1086 SIGDELSET(ps->ps_siginfo, sig); 1087 } 1088 1089 /* 1090 * Reset signals for an exec of the specified process. 1091 */ 1092 void 1093 execsigs(struct proc *p) 1094 { 1095 struct sigacts *ps; 1096 struct thread *td; 1097 1098 /* 1099 * Reset caught signals. Held signals remain held 1100 * through td_sigmask (unless they were caught, 1101 * and are now ignored by default). 1102 */ 1103 PROC_LOCK_ASSERT(p, MA_OWNED); 1104 ps = p->p_sigacts; 1105 mtx_lock(&ps->ps_mtx); 1106 sig_drop_caught(p); 1107 1108 /* 1109 * Reset stack state to the user stack. 1110 * Clear set of signals caught on the signal stack. 1111 */ 1112 td = curthread; 1113 MPASS(td->td_proc == p); 1114 td->td_sigstk.ss_flags = SS_DISABLE; 1115 td->td_sigstk.ss_size = 0; 1116 td->td_sigstk.ss_sp = 0; 1117 td->td_pflags &= ~TDP_ALTSTACK; 1118 /* 1119 * Reset no zombies if child dies flag as Solaris does. 1120 */ 1121 ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 1122 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 1123 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 1124 mtx_unlock(&ps->ps_mtx); 1125 } 1126 1127 /* 1128 * kern_sigprocmask() 1129 * 1130 * Manipulate signal mask. 1131 */ 1132 int 1133 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset, 1134 int flags) 1135 { 1136 sigset_t new_block, oset1; 1137 struct proc *p; 1138 int error; 1139 1140 p = td->td_proc; 1141 if ((flags & SIGPROCMASK_PROC_LOCKED) != 0) 1142 PROC_LOCK_ASSERT(p, MA_OWNED); 1143 else 1144 PROC_LOCK(p); 1145 mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 1146 ? MA_OWNED : MA_NOTOWNED); 1147 if (oset != NULL) 1148 *oset = td->td_sigmask; 1149 1150 error = 0; 1151 if (set != NULL) { 1152 switch (how) { 1153 case SIG_BLOCK: 1154 SIG_CANTMASK(*set); 1155 oset1 = td->td_sigmask; 1156 SIGSETOR(td->td_sigmask, *set); 1157 new_block = td->td_sigmask; 1158 SIGSETNAND(new_block, oset1); 1159 break; 1160 case SIG_UNBLOCK: 1161 SIGSETNAND(td->td_sigmask, *set); 1162 signotify(td); 1163 goto out; 1164 case SIG_SETMASK: 1165 SIG_CANTMASK(*set); 1166 oset1 = td->td_sigmask; 1167 if (flags & SIGPROCMASK_OLD) 1168 SIGSETLO(td->td_sigmask, *set); 1169 else 1170 td->td_sigmask = *set; 1171 new_block = td->td_sigmask; 1172 SIGSETNAND(new_block, oset1); 1173 signotify(td); 1174 break; 1175 default: 1176 error = EINVAL; 1177 goto out; 1178 } 1179 1180 /* 1181 * The new_block set contains signals that were not previously 1182 * blocked, but are blocked now. 1183 * 1184 * In case we block any signal that was not previously blocked 1185 * for td, and process has the signal pending, try to schedule 1186 * signal delivery to some thread that does not block the 1187 * signal, possibly waking it up. 1188 */ 1189 if (p->p_numthreads != 1) 1190 reschedule_signals(p, new_block, flags); 1191 } 1192 1193 out: 1194 if (!(flags & SIGPROCMASK_PROC_LOCKED)) 1195 PROC_UNLOCK(p); 1196 return (error); 1197 } 1198 1199 #ifndef _SYS_SYSPROTO_H_ 1200 struct sigprocmask_args { 1201 int how; 1202 const sigset_t *set; 1203 sigset_t *oset; 1204 }; 1205 #endif 1206 int 1207 sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap) 1208 { 1209 sigset_t set, oset; 1210 sigset_t *setp, *osetp; 1211 int error; 1212 1213 setp = (uap->set != NULL) ? &set : NULL; 1214 osetp = (uap->oset != NULL) ? &oset : NULL; 1215 if (setp) { 1216 error = copyin(uap->set, setp, sizeof(set)); 1217 if (error) 1218 return (error); 1219 } 1220 error = kern_sigprocmask(td, uap->how, setp, osetp, 0); 1221 if (osetp && !error) { 1222 error = copyout(osetp, uap->oset, sizeof(oset)); 1223 } 1224 return (error); 1225 } 1226 1227 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1228 #ifndef _SYS_SYSPROTO_H_ 1229 struct osigprocmask_args { 1230 int how; 1231 osigset_t mask; 1232 }; 1233 #endif 1234 int 1235 osigprocmask(struct thread *td, struct osigprocmask_args *uap) 1236 { 1237 sigset_t set, oset; 1238 int error; 1239 1240 OSIG2SIG(uap->mask, set); 1241 error = kern_sigprocmask(td, uap->how, &set, &oset, 1); 1242 SIG2OSIG(oset, td->td_retval[0]); 1243 return (error); 1244 } 1245 #endif /* COMPAT_43 */ 1246 1247 int 1248 sys_sigwait(struct thread *td, struct sigwait_args *uap) 1249 { 1250 ksiginfo_t ksi; 1251 sigset_t set; 1252 int error; 1253 1254 error = copyin(uap->set, &set, sizeof(set)); 1255 if (error) { 1256 td->td_retval[0] = error; 1257 return (0); 1258 } 1259 1260 error = kern_sigtimedwait(td, set, &ksi, NULL); 1261 if (error) { 1262 /* 1263 * sigwait() function shall not return EINTR, but 1264 * the syscall does. Non-ancient libc provides the 1265 * wrapper which hides EINTR. Otherwise, EINTR return 1266 * is used by libthr to handle required cancellation 1267 * point in the sigwait(). 1268 */ 1269 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT) 1270 return (ERESTART); 1271 td->td_retval[0] = error; 1272 return (0); 1273 } 1274 1275 error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo)); 1276 td->td_retval[0] = error; 1277 return (0); 1278 } 1279 1280 int 1281 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap) 1282 { 1283 struct timespec ts; 1284 struct timespec *timeout; 1285 sigset_t set; 1286 ksiginfo_t ksi; 1287 int error; 1288 1289 if (uap->timeout) { 1290 error = copyin(uap->timeout, &ts, sizeof(ts)); 1291 if (error) 1292 return (error); 1293 1294 timeout = &ts; 1295 } else 1296 timeout = NULL; 1297 1298 error = copyin(uap->set, &set, sizeof(set)); 1299 if (error) 1300 return (error); 1301 1302 error = kern_sigtimedwait(td, set, &ksi, timeout); 1303 if (error) 1304 return (error); 1305 1306 if (uap->info) 1307 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1308 1309 if (error == 0) 1310 td->td_retval[0] = ksi.ksi_signo; 1311 return (error); 1312 } 1313 1314 int 1315 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap) 1316 { 1317 ksiginfo_t ksi; 1318 sigset_t set; 1319 int error; 1320 1321 error = copyin(uap->set, &set, sizeof(set)); 1322 if (error) 1323 return (error); 1324 1325 error = kern_sigtimedwait(td, set, &ksi, NULL); 1326 if (error) 1327 return (error); 1328 1329 if (uap->info) 1330 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); 1331 1332 if (error == 0) 1333 td->td_retval[0] = ksi.ksi_signo; 1334 return (error); 1335 } 1336 1337 static void 1338 proc_td_siginfo_capture(struct thread *td, siginfo_t *si) 1339 { 1340 struct thread *thr; 1341 1342 FOREACH_THREAD_IN_PROC(td->td_proc, thr) { 1343 if (thr == td) 1344 thr->td_si = *si; 1345 else 1346 thr->td_si.si_signo = 0; 1347 } 1348 } 1349 1350 int 1351 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi, 1352 struct timespec *timeout) 1353 { 1354 struct sigacts *ps; 1355 sigset_t saved_mask, new_block; 1356 struct proc *p; 1357 int error, sig, timevalid = 0; 1358 sbintime_t sbt, precision, tsbt; 1359 struct timespec ts; 1360 bool traced; 1361 1362 p = td->td_proc; 1363 error = 0; 1364 traced = false; 1365 1366 /* Ensure the sigfastblock value is up to date. */ 1367 sigfastblock_fetch(td); 1368 1369 if (timeout != NULL) { 1370 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { 1371 timevalid = 1; 1372 ts = *timeout; 1373 if (ts.tv_sec < INT32_MAX / 2) { 1374 tsbt = tstosbt(ts); 1375 precision = tsbt; 1376 precision >>= tc_precexp; 1377 if (TIMESEL(&sbt, tsbt)) 1378 sbt += tc_tick_sbt; 1379 sbt += tsbt; 1380 } else 1381 precision = sbt = 0; 1382 } 1383 } else 1384 precision = sbt = 0; 1385 ksiginfo_init(ksi); 1386 /* Some signals can not be waited for. */ 1387 SIG_CANTMASK(waitset); 1388 ps = p->p_sigacts; 1389 PROC_LOCK(p); 1390 saved_mask = td->td_sigmask; 1391 SIGSETNAND(td->td_sigmask, waitset); 1392 if ((p->p_sysent->sv_flags & SV_SIG_DISCIGN) != 0 || 1393 !kern_sig_discard_ign) { 1394 thread_lock(td); 1395 td->td_flags |= TDF_SIGWAIT; 1396 thread_unlock(td); 1397 } 1398 for (;;) { 1399 mtx_lock(&ps->ps_mtx); 1400 sig = cursig(td); 1401 mtx_unlock(&ps->ps_mtx); 1402 KASSERT(sig >= 0, ("sig %d", sig)); 1403 if (sig != 0 && SIGISMEMBER(waitset, sig)) { 1404 if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 || 1405 sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) { 1406 error = 0; 1407 break; 1408 } 1409 } 1410 1411 if (error != 0) 1412 break; 1413 1414 /* 1415 * POSIX says this must be checked after looking for pending 1416 * signals. 1417 */ 1418 if (timeout != NULL && !timevalid) { 1419 error = EINVAL; 1420 break; 1421 } 1422 1423 if (traced) { 1424 error = EINTR; 1425 break; 1426 } 1427 1428 error = msleep_sbt(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH, 1429 "sigwait", sbt, precision, C_ABSOLUTE); 1430 1431 /* The syscalls can not be restarted. */ 1432 if (error == ERESTART) 1433 error = EINTR; 1434 1435 /* 1436 * If PTRACE_SCE or PTRACE_SCX were set after 1437 * userspace entered the syscall, return spurious 1438 * EINTR after wait was done. Only do this as last 1439 * resort after rechecking for possible queued signals 1440 * and expired timeouts. 1441 */ 1442 if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0) 1443 traced = true; 1444 } 1445 thread_lock(td); 1446 td->td_flags &= ~TDF_SIGWAIT; 1447 thread_unlock(td); 1448 1449 new_block = saved_mask; 1450 SIGSETNAND(new_block, td->td_sigmask); 1451 td->td_sigmask = saved_mask; 1452 /* 1453 * Fewer signals can be delivered to us, reschedule signal 1454 * notification. 1455 */ 1456 if (p->p_numthreads != 1) 1457 reschedule_signals(p, new_block, 0); 1458 1459 if (error == 0) { 1460 SDT_PROBE2(proc, , , signal__clear, sig, ksi); 1461 1462 if (ksi->ksi_code == SI_TIMER) 1463 itimer_accept(p, ksi->ksi_timerid, ksi); 1464 1465 #ifdef KTRACE 1466 if (KTRPOINT(td, KTR_PSIG)) { 1467 sig_t action; 1468 1469 mtx_lock(&ps->ps_mtx); 1470 action = ps->ps_sigact[_SIG_IDX(sig)]; 1471 mtx_unlock(&ps->ps_mtx); 1472 ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code); 1473 } 1474 #endif 1475 if (sig == SIGKILL) { 1476 proc_td_siginfo_capture(td, &ksi->ksi_info); 1477 sigexit(td, sig); 1478 } 1479 } 1480 PROC_UNLOCK(p); 1481 return (error); 1482 } 1483 1484 #ifndef _SYS_SYSPROTO_H_ 1485 struct sigpending_args { 1486 sigset_t *set; 1487 }; 1488 #endif 1489 int 1490 sys_sigpending(struct thread *td, struct sigpending_args *uap) 1491 { 1492 struct proc *p = td->td_proc; 1493 sigset_t pending; 1494 1495 PROC_LOCK(p); 1496 pending = p->p_sigqueue.sq_signals; 1497 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1498 PROC_UNLOCK(p); 1499 return (copyout(&pending, uap->set, sizeof(sigset_t))); 1500 } 1501 1502 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1503 #ifndef _SYS_SYSPROTO_H_ 1504 struct osigpending_args { 1505 int dummy; 1506 }; 1507 #endif 1508 int 1509 osigpending(struct thread *td, struct osigpending_args *uap) 1510 { 1511 struct proc *p = td->td_proc; 1512 sigset_t pending; 1513 1514 PROC_LOCK(p); 1515 pending = p->p_sigqueue.sq_signals; 1516 SIGSETOR(pending, td->td_sigqueue.sq_signals); 1517 PROC_UNLOCK(p); 1518 SIG2OSIG(pending, td->td_retval[0]); 1519 return (0); 1520 } 1521 #endif /* COMPAT_43 */ 1522 1523 #if defined(COMPAT_43) 1524 /* 1525 * Generalized interface signal handler, 4.3-compatible. 1526 */ 1527 #ifndef _SYS_SYSPROTO_H_ 1528 struct osigvec_args { 1529 int signum; 1530 struct sigvec *nsv; 1531 struct sigvec *osv; 1532 }; 1533 #endif 1534 /* ARGSUSED */ 1535 int 1536 osigvec(struct thread *td, struct osigvec_args *uap) 1537 { 1538 struct sigvec vec; 1539 struct sigaction nsa, osa; 1540 struct sigaction *nsap, *osap; 1541 int error; 1542 1543 if (uap->signum <= 0 || uap->signum >= ONSIG) 1544 return (EINVAL); 1545 nsap = (uap->nsv != NULL) ? &nsa : NULL; 1546 osap = (uap->osv != NULL) ? &osa : NULL; 1547 if (nsap) { 1548 error = copyin(uap->nsv, &vec, sizeof(vec)); 1549 if (error) 1550 return (error); 1551 nsap->sa_handler = vec.sv_handler; 1552 OSIG2SIG(vec.sv_mask, nsap->sa_mask); 1553 nsap->sa_flags = vec.sv_flags; 1554 nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ 1555 } 1556 error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); 1557 if (osap && !error) { 1558 vec.sv_handler = osap->sa_handler; 1559 SIG2OSIG(osap->sa_mask, vec.sv_mask); 1560 vec.sv_flags = osap->sa_flags; 1561 vec.sv_flags &= ~SA_NOCLDWAIT; 1562 vec.sv_flags ^= SA_RESTART; 1563 error = copyout(&vec, uap->osv, sizeof(vec)); 1564 } 1565 return (error); 1566 } 1567 1568 #ifndef _SYS_SYSPROTO_H_ 1569 struct osigblock_args { 1570 int mask; 1571 }; 1572 #endif 1573 int 1574 osigblock(struct thread *td, struct osigblock_args *uap) 1575 { 1576 sigset_t set, oset; 1577 1578 OSIG2SIG(uap->mask, set); 1579 kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0); 1580 SIG2OSIG(oset, td->td_retval[0]); 1581 return (0); 1582 } 1583 1584 #ifndef _SYS_SYSPROTO_H_ 1585 struct osigsetmask_args { 1586 int mask; 1587 }; 1588 #endif 1589 int 1590 osigsetmask(struct thread *td, struct osigsetmask_args *uap) 1591 { 1592 sigset_t set, oset; 1593 1594 OSIG2SIG(uap->mask, set); 1595 kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0); 1596 SIG2OSIG(oset, td->td_retval[0]); 1597 return (0); 1598 } 1599 #endif /* COMPAT_43 */ 1600 1601 /* 1602 * Suspend calling thread until signal, providing mask to be set in the 1603 * meantime. 1604 */ 1605 #ifndef _SYS_SYSPROTO_H_ 1606 struct sigsuspend_args { 1607 const sigset_t *sigmask; 1608 }; 1609 #endif 1610 /* ARGSUSED */ 1611 int 1612 sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap) 1613 { 1614 sigset_t mask; 1615 int error; 1616 1617 error = copyin(uap->sigmask, &mask, sizeof(mask)); 1618 if (error) 1619 return (error); 1620 return (kern_sigsuspend(td, mask)); 1621 } 1622 1623 int 1624 kern_sigsuspend(struct thread *td, sigset_t mask) 1625 { 1626 struct proc *p = td->td_proc; 1627 int has_sig, sig; 1628 1629 /* Ensure the sigfastblock value is up to date. */ 1630 sigfastblock_fetch(td); 1631 1632 /* 1633 * When returning from sigsuspend, we want 1634 * the old mask to be restored after the 1635 * signal handler has finished. Thus, we 1636 * save it here and mark the sigacts structure 1637 * to indicate this. 1638 */ 1639 PROC_LOCK(p); 1640 kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask, 1641 SIGPROCMASK_PROC_LOCKED); 1642 td->td_pflags |= TDP_OLDMASK; 1643 ast_sched(td, TDA_SIGSUSPEND); 1644 1645 /* 1646 * Process signals now. Otherwise, we can get spurious wakeup 1647 * due to signal entered process queue, but delivered to other 1648 * thread. But sigsuspend should return only on signal 1649 * delivery. 1650 */ 1651 (p->p_sysent->sv_set_syscall_retval)(td, EINTR); 1652 for (has_sig = 0; !has_sig;) { 1653 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 1654 0) == 0) 1655 /* void */; 1656 thread_suspend_check(0); 1657 mtx_lock(&p->p_sigacts->ps_mtx); 1658 while ((sig = cursig(td)) != 0) { 1659 KASSERT(sig >= 0, ("sig %d", sig)); 1660 has_sig += postsig(sig); 1661 } 1662 mtx_unlock(&p->p_sigacts->ps_mtx); 1663 1664 /* 1665 * If PTRACE_SCE or PTRACE_SCX were set after 1666 * userspace entered the syscall, return spurious 1667 * EINTR. 1668 */ 1669 if ((p->p_ptevents & PTRACE_SYSCALL) != 0) 1670 has_sig += 1; 1671 } 1672 PROC_UNLOCK(p); 1673 td->td_errno = EINTR; 1674 td->td_pflags |= TDP_NERRNO; 1675 return (EJUSTRETURN); 1676 } 1677 1678 #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ 1679 /* 1680 * Compatibility sigsuspend call for old binaries. Note nonstandard calling 1681 * convention: libc stub passes mask, not pointer, to save a copyin. 1682 */ 1683 #ifndef _SYS_SYSPROTO_H_ 1684 struct osigsuspend_args { 1685 osigset_t mask; 1686 }; 1687 #endif 1688 /* ARGSUSED */ 1689 int 1690 osigsuspend(struct thread *td, struct osigsuspend_args *uap) 1691 { 1692 sigset_t mask; 1693 1694 OSIG2SIG(uap->mask, mask); 1695 return (kern_sigsuspend(td, mask)); 1696 } 1697 #endif /* COMPAT_43 */ 1698 1699 #if defined(COMPAT_43) 1700 #ifndef _SYS_SYSPROTO_H_ 1701 struct osigstack_args { 1702 struct sigstack *nss; 1703 struct sigstack *oss; 1704 }; 1705 #endif 1706 /* ARGSUSED */ 1707 int 1708 osigstack(struct thread *td, struct osigstack_args *uap) 1709 { 1710 struct sigstack nss, oss; 1711 int error = 0; 1712 1713 if (uap->nss != NULL) { 1714 error = copyin(uap->nss, &nss, sizeof(nss)); 1715 if (error) 1716 return (error); 1717 } 1718 oss.ss_sp = td->td_sigstk.ss_sp; 1719 oss.ss_onstack = sigonstack(cpu_getstack(td)); 1720 if (uap->nss != NULL) { 1721 td->td_sigstk.ss_sp = nss.ss_sp; 1722 td->td_sigstk.ss_size = 0; 1723 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK; 1724 td->td_pflags |= TDP_ALTSTACK; 1725 } 1726 if (uap->oss != NULL) 1727 error = copyout(&oss, uap->oss, sizeof(oss)); 1728 1729 return (error); 1730 } 1731 #endif /* COMPAT_43 */ 1732 1733 #ifndef _SYS_SYSPROTO_H_ 1734 struct sigaltstack_args { 1735 stack_t *ss; 1736 stack_t *oss; 1737 }; 1738 #endif 1739 /* ARGSUSED */ 1740 int 1741 sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap) 1742 { 1743 stack_t ss, oss; 1744 int error; 1745 1746 if (uap->ss != NULL) { 1747 error = copyin(uap->ss, &ss, sizeof(ss)); 1748 if (error) 1749 return (error); 1750 } 1751 error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL, 1752 (uap->oss != NULL) ? &oss : NULL); 1753 if (error) 1754 return (error); 1755 if (uap->oss != NULL) 1756 error = copyout(&oss, uap->oss, sizeof(stack_t)); 1757 return (error); 1758 } 1759 1760 int 1761 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss) 1762 { 1763 struct proc *p = td->td_proc; 1764 int oonstack; 1765 1766 oonstack = sigonstack(cpu_getstack(td)); 1767 1768 if (oss != NULL) { 1769 *oss = td->td_sigstk; 1770 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK) 1771 ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; 1772 } 1773 1774 if (ss != NULL) { 1775 if (oonstack) 1776 return (EPERM); 1777 if ((ss->ss_flags & ~SS_DISABLE) != 0) 1778 return (EINVAL); 1779 if (!(ss->ss_flags & SS_DISABLE)) { 1780 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 1781 return (ENOMEM); 1782 1783 td->td_sigstk = *ss; 1784 td->td_pflags |= TDP_ALTSTACK; 1785 } else { 1786 td->td_pflags &= ~TDP_ALTSTACK; 1787 } 1788 } 1789 return (0); 1790 } 1791 1792 struct killpg1_ctx { 1793 struct thread *td; 1794 ksiginfo_t *ksi; 1795 int sig; 1796 bool sent; 1797 bool found; 1798 int ret; 1799 }; 1800 1801 static void 1802 killpg1_sendsig_locked(struct proc *p, struct killpg1_ctx *arg) 1803 { 1804 int err; 1805 1806 err = p_cansignal(arg->td, p, arg->sig); 1807 if (err == 0 && arg->sig != 0) 1808 pksignal(p, arg->sig, arg->ksi); 1809 if (err != ESRCH) 1810 arg->found = true; 1811 if (err == 0) 1812 arg->sent = true; 1813 else if (arg->ret == 0 && err != ESRCH && err != EPERM) 1814 arg->ret = err; 1815 } 1816 1817 static void 1818 killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg) 1819 { 1820 1821 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 || 1822 (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW) 1823 return; 1824 1825 PROC_LOCK(p); 1826 killpg1_sendsig_locked(p, arg); 1827 PROC_UNLOCK(p); 1828 } 1829 1830 static void 1831 kill_processes_prison_cb(struct proc *p, void *arg) 1832 { 1833 struct killpg1_ctx *ctx = arg; 1834 1835 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 || 1836 (p == ctx->td->td_proc) || p->p_state == PRS_NEW) 1837 return; 1838 1839 killpg1_sendsig_locked(p, ctx); 1840 } 1841 1842 /* 1843 * Common code for kill process group/broadcast kill. 1844 * td is the calling thread, as usual. 1845 */ 1846 static int 1847 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi) 1848 { 1849 struct proc *p; 1850 struct pgrp *pgrp; 1851 struct killpg1_ctx arg; 1852 1853 arg.td = td; 1854 arg.ksi = ksi; 1855 arg.sig = sig; 1856 arg.sent = false; 1857 arg.found = false; 1858 arg.ret = 0; 1859 if (all) { 1860 /* 1861 * broadcast 1862 */ 1863 prison_proc_iterate(td->td_ucred->cr_prison, 1864 kill_processes_prison_cb, &arg); 1865 } else { 1866 again: 1867 sx_slock(&proctree_lock); 1868 if (pgid == 0) { 1869 /* 1870 * zero pgid means send to my process group. 1871 */ 1872 pgrp = td->td_proc->p_pgrp; 1873 PGRP_LOCK(pgrp); 1874 } else { 1875 pgrp = pgfind(pgid); 1876 if (pgrp == NULL) { 1877 sx_sunlock(&proctree_lock); 1878 return (ESRCH); 1879 } 1880 } 1881 sx_sunlock(&proctree_lock); 1882 if (!sx_try_xlock(&pgrp->pg_killsx)) { 1883 PGRP_UNLOCK(pgrp); 1884 sx_xlock(&pgrp->pg_killsx); 1885 sx_xunlock(&pgrp->pg_killsx); 1886 goto again; 1887 } 1888 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 1889 killpg1_sendsig(p, false, &arg); 1890 } 1891 PGRP_UNLOCK(pgrp); 1892 sx_xunlock(&pgrp->pg_killsx); 1893 } 1894 MPASS(arg.ret != 0 || arg.found || !arg.sent); 1895 if (arg.ret == 0 && !arg.sent) 1896 arg.ret = arg.found ? EPERM : ESRCH; 1897 return (arg.ret); 1898 } 1899 1900 #ifndef _SYS_SYSPROTO_H_ 1901 struct kill_args { 1902 int pid; 1903 int signum; 1904 }; 1905 #endif 1906 /* ARGSUSED */ 1907 int 1908 sys_kill(struct thread *td, struct kill_args *uap) 1909 { 1910 1911 return (kern_kill(td, uap->pid, uap->signum)); 1912 } 1913 1914 int 1915 kern_kill(struct thread *td, pid_t pid, int signum) 1916 { 1917 ksiginfo_t ksi; 1918 struct proc *p; 1919 int error; 1920 1921 /* 1922 * A process in capability mode can send signals only to himself. 1923 * The main rationale behind this is that abort(3) is implemented as 1924 * kill(getpid(), SIGABRT). 1925 */ 1926 if (pid != td->td_proc->p_pid) { 1927 if (CAP_TRACING(td)) 1928 ktrcapfail(CAPFAIL_SIGNAL, &signum); 1929 if (IN_CAPABILITY_MODE(td)) 1930 return (ECAPMODE); 1931 } 1932 1933 AUDIT_ARG_SIGNUM(signum); 1934 AUDIT_ARG_PID(pid); 1935 if ((u_int)signum > _SIG_MAXSIG) 1936 return (EINVAL); 1937 1938 ksiginfo_init(&ksi); 1939 ksi.ksi_signo = signum; 1940 ksi.ksi_code = SI_USER; 1941 ksi.ksi_pid = td->td_proc->p_pid; 1942 ksi.ksi_uid = td->td_ucred->cr_ruid; 1943 1944 if (pid > 0) { 1945 /* kill single process */ 1946 if ((p = pfind_any(pid)) == NULL) 1947 return (ESRCH); 1948 AUDIT_ARG_PROCESS(p); 1949 error = p_cansignal(td, p, signum); 1950 if (error == 0 && signum) 1951 pksignal(p, signum, &ksi); 1952 PROC_UNLOCK(p); 1953 return (error); 1954 } 1955 switch (pid) { 1956 case -1: /* broadcast signal */ 1957 return (killpg1(td, signum, 0, 1, &ksi)); 1958 case 0: /* signal own process group */ 1959 return (killpg1(td, signum, 0, 0, &ksi)); 1960 default: /* negative explicit process group */ 1961 return (killpg1(td, signum, -pid, 0, &ksi)); 1962 } 1963 /* NOTREACHED */ 1964 } 1965 1966 int 1967 sys_pdkill(struct thread *td, struct pdkill_args *uap) 1968 { 1969 struct proc *p; 1970 int error; 1971 1972 AUDIT_ARG_SIGNUM(uap->signum); 1973 AUDIT_ARG_FD(uap->fd); 1974 if ((u_int)uap->signum > _SIG_MAXSIG) 1975 return (EINVAL); 1976 1977 error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p); 1978 if (error) 1979 return (error); 1980 AUDIT_ARG_PROCESS(p); 1981 error = p_cansignal(td, p, uap->signum); 1982 if (error == 0 && uap->signum) 1983 kern_psignal(p, uap->signum); 1984 PROC_UNLOCK(p); 1985 return (error); 1986 } 1987 1988 #if defined(COMPAT_43) 1989 #ifndef _SYS_SYSPROTO_H_ 1990 struct okillpg_args { 1991 int pgid; 1992 int signum; 1993 }; 1994 #endif 1995 /* ARGSUSED */ 1996 int 1997 okillpg(struct thread *td, struct okillpg_args *uap) 1998 { 1999 ksiginfo_t ksi; 2000 2001 AUDIT_ARG_SIGNUM(uap->signum); 2002 AUDIT_ARG_PID(uap->pgid); 2003 if ((u_int)uap->signum > _SIG_MAXSIG) 2004 return (EINVAL); 2005 2006 ksiginfo_init(&ksi); 2007 ksi.ksi_signo = uap->signum; 2008 ksi.ksi_code = SI_USER; 2009 ksi.ksi_pid = td->td_proc->p_pid; 2010 ksi.ksi_uid = td->td_ucred->cr_ruid; 2011 return (killpg1(td, uap->signum, uap->pgid, 0, &ksi)); 2012 } 2013 #endif /* COMPAT_43 */ 2014 2015 #ifndef _SYS_SYSPROTO_H_ 2016 struct sigqueue_args { 2017 pid_t pid; 2018 int signum; 2019 /* union sigval */ void *value; 2020 }; 2021 #endif 2022 int 2023 sys_sigqueue(struct thread *td, struct sigqueue_args *uap) 2024 { 2025 union sigval sv; 2026 2027 sv.sival_ptr = uap->value; 2028 2029 return (kern_sigqueue(td, uap->pid, uap->signum, &sv)); 2030 } 2031 2032 int 2033 kern_sigqueue(struct thread *td, pid_t pid, int signumf, union sigval *value) 2034 { 2035 ksiginfo_t ksi; 2036 struct proc *p; 2037 struct thread *td2; 2038 u_int signum; 2039 int error; 2040 2041 signum = signumf & ~__SIGQUEUE_TID; 2042 if (signum > _SIG_MAXSIG) 2043 return (EINVAL); 2044 2045 /* 2046 * Specification says sigqueue can only send signal to 2047 * single process. 2048 */ 2049 if (pid <= 0) 2050 return (EINVAL); 2051 2052 if ((signumf & __SIGQUEUE_TID) == 0) { 2053 if ((p = pfind_any(pid)) == NULL) 2054 return (ESRCH); 2055 td2 = NULL; 2056 } else { 2057 p = td->td_proc; 2058 td2 = tdfind((lwpid_t)pid, p->p_pid); 2059 if (td2 == NULL) 2060 return (ESRCH); 2061 } 2062 2063 error = p_cansignal(td, p, signum); 2064 if (error == 0 && signum != 0) { 2065 ksiginfo_init(&ksi); 2066 ksi.ksi_flags = KSI_SIGQ; 2067 ksi.ksi_signo = signum; 2068 ksi.ksi_code = SI_QUEUE; 2069 ksi.ksi_pid = td->td_proc->p_pid; 2070 ksi.ksi_uid = td->td_ucred->cr_ruid; 2071 ksi.ksi_value = *value; 2072 error = tdsendsignal(p, td2, ksi.ksi_signo, &ksi); 2073 } 2074 PROC_UNLOCK(p); 2075 return (error); 2076 } 2077 2078 /* 2079 * Send a signal to a process group. If checktty is 1, 2080 * limit to members which have a controlling terminal. 2081 */ 2082 void 2083 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi) 2084 { 2085 struct proc *p; 2086 2087 if (pgrp) { 2088 PGRP_LOCK_ASSERT(pgrp, MA_OWNED); 2089 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 2090 PROC_LOCK(p); 2091 if (p->p_state == PRS_NORMAL && 2092 (checkctty == 0 || p->p_flag & P_CONTROLT)) 2093 pksignal(p, sig, ksi); 2094 PROC_UNLOCK(p); 2095 } 2096 } 2097 } 2098 2099 /* 2100 * Recalculate the signal mask and reset the signal disposition after 2101 * usermode frame for delivery is formed. Should be called after 2102 * mach-specific routine, because sysent->sv_sendsig() needs correct 2103 * ps_siginfo and signal mask. 2104 */ 2105 static void 2106 postsig_done(int sig, struct thread *td, struct sigacts *ps) 2107 { 2108 sigset_t mask; 2109 2110 mtx_assert(&ps->ps_mtx, MA_OWNED); 2111 td->td_ru.ru_nsignals++; 2112 mask = ps->ps_catchmask[_SIG_IDX(sig)]; 2113 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2114 SIGADDSET(mask, sig); 2115 kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, 2116 SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); 2117 if (SIGISMEMBER(ps->ps_sigreset, sig)) 2118 sigdflt(ps, sig); 2119 } 2120 2121 /* 2122 * Send a signal caused by a trap to the current thread. If it will be 2123 * caught immediately, deliver it with correct code. Otherwise, post it 2124 * normally. 2125 */ 2126 void 2127 trapsignal(struct thread *td, ksiginfo_t *ksi) 2128 { 2129 struct sigacts *ps; 2130 struct proc *p; 2131 sigset_t sigmask; 2132 int sig; 2133 2134 p = td->td_proc; 2135 sig = ksi->ksi_signo; 2136 KASSERT(_SIG_VALID(sig), ("invalid signal")); 2137 2138 sigfastblock_fetch(td); 2139 PROC_LOCK(p); 2140 ps = p->p_sigacts; 2141 mtx_lock(&ps->ps_mtx); 2142 sigmask = td->td_sigmask; 2143 if (td->td_sigblock_val != 0) 2144 SIGSETOR(sigmask, fastblock_mask); 2145 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) && 2146 !SIGISMEMBER(sigmask, sig)) { 2147 #ifdef KTRACE 2148 if (KTRPOINT(curthread, KTR_PSIG)) 2149 ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)], 2150 &td->td_sigmask, ksi->ksi_code); 2151 #endif 2152 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], 2153 ksi, &td->td_sigmask); 2154 postsig_done(sig, td, ps); 2155 mtx_unlock(&ps->ps_mtx); 2156 } else { 2157 /* 2158 * Avoid a possible infinite loop if the thread 2159 * masking the signal or process is ignoring the 2160 * signal. 2161 */ 2162 if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) || 2163 ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) { 2164 SIGDELSET(td->td_sigmask, sig); 2165 SIGDELSET(ps->ps_sigcatch, sig); 2166 SIGDELSET(ps->ps_sigignore, sig); 2167 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2168 td->td_pflags &= ~TDP_SIGFASTBLOCK; 2169 td->td_sigblock_val = 0; 2170 } 2171 mtx_unlock(&ps->ps_mtx); 2172 p->p_sig = sig; /* XXX to verify code */ 2173 tdsendsignal(p, td, sig, ksi); 2174 } 2175 PROC_UNLOCK(p); 2176 } 2177 2178 static struct thread * 2179 sigtd(struct proc *p, int sig, bool fast_sigblock) 2180 { 2181 struct thread *td, *signal_td; 2182 2183 PROC_LOCK_ASSERT(p, MA_OWNED); 2184 MPASS(!fast_sigblock || p == curproc); 2185 2186 /* 2187 * Check if current thread can handle the signal without 2188 * switching context to another thread. 2189 */ 2190 if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) && 2191 (!fast_sigblock || curthread->td_sigblock_val == 0)) 2192 return (curthread); 2193 2194 /* Find a non-stopped thread that does not mask the signal. */ 2195 signal_td = NULL; 2196 FOREACH_THREAD_IN_PROC(p, td) { 2197 if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock || 2198 td != curthread || td->td_sigblock_val == 0) && 2199 (td->td_flags & TDF_BOUNDARY) == 0) { 2200 signal_td = td; 2201 break; 2202 } 2203 } 2204 /* Select random (first) thread if no better match was found. */ 2205 if (signal_td == NULL) 2206 signal_td = FIRST_THREAD_IN_PROC(p); 2207 return (signal_td); 2208 } 2209 2210 /* 2211 * Send the signal to the process. If the signal has an action, the action 2212 * is usually performed by the target process rather than the caller; we add 2213 * the signal to the set of pending signals for the process. 2214 * 2215 * Exceptions: 2216 * o When a stop signal is sent to a sleeping process that takes the 2217 * default action, the process is stopped without awakening it. 2218 * o SIGCONT restarts stopped processes (or puts them back to sleep) 2219 * regardless of the signal action (eg, blocked or ignored). 2220 * 2221 * Other ignored signals are discarded immediately. 2222 * 2223 * NB: This function may be entered from the debugger via the "kill" DDB 2224 * command. There is little that can be done to mitigate the possibly messy 2225 * side effects of this unwise possibility. 2226 */ 2227 void 2228 kern_psignal(struct proc *p, int sig) 2229 { 2230 ksiginfo_t ksi; 2231 2232 ksiginfo_init(&ksi); 2233 ksi.ksi_signo = sig; 2234 ksi.ksi_code = SI_KERNEL; 2235 (void) tdsendsignal(p, NULL, sig, &ksi); 2236 } 2237 2238 int 2239 pksignal(struct proc *p, int sig, ksiginfo_t *ksi) 2240 { 2241 2242 return (tdsendsignal(p, NULL, sig, ksi)); 2243 } 2244 2245 /* Utility function for finding a thread to send signal event to. */ 2246 int 2247 sigev_findtd(struct proc *p, struct sigevent *sigev, struct thread **ttd) 2248 { 2249 struct thread *td; 2250 2251 if (sigev->sigev_notify == SIGEV_THREAD_ID) { 2252 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid); 2253 if (td == NULL) 2254 return (ESRCH); 2255 *ttd = td; 2256 } else { 2257 *ttd = NULL; 2258 PROC_LOCK(p); 2259 } 2260 return (0); 2261 } 2262 2263 void 2264 tdsignal(struct thread *td, int sig) 2265 { 2266 ksiginfo_t ksi; 2267 2268 ksiginfo_init(&ksi); 2269 ksi.ksi_signo = sig; 2270 ksi.ksi_code = SI_KERNEL; 2271 (void) tdsendsignal(td->td_proc, td, sig, &ksi); 2272 } 2273 2274 void 2275 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi) 2276 { 2277 2278 (void) tdsendsignal(td->td_proc, td, sig, ksi); 2279 } 2280 2281 static void 2282 sig_sleepq_abort(struct thread *td, int intrval) 2283 { 2284 THREAD_LOCK_ASSERT(td, MA_OWNED); 2285 2286 if (intrval == 0 && (td->td_flags & TDF_SIGWAIT) == 0) 2287 thread_unlock(td); 2288 else 2289 sleepq_abort(td, intrval); 2290 } 2291 2292 int 2293 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) 2294 { 2295 sig_t action; 2296 sigqueue_t *sigqueue; 2297 struct sigacts *ps; 2298 int intrval, prop, ret; 2299 2300 MPASS(td == NULL || p == td->td_proc); 2301 PROC_LOCK_ASSERT(p, MA_OWNED); 2302 2303 if (!_SIG_VALID(sig)) 2304 panic("%s(): invalid signal %d", __func__, sig); 2305 2306 KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__)); 2307 2308 /* 2309 * IEEE Std 1003.1-2001: return success when killing a zombie. 2310 */ 2311 if (p->p_state == PRS_ZOMBIE) { 2312 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0) 2313 ksiginfo_tryfree(ksi); 2314 return (0); 2315 } 2316 2317 ps = p->p_sigacts; 2318 KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig); 2319 prop = sigprop(sig); 2320 2321 if (td == NULL) { 2322 td = sigtd(p, sig, false); 2323 sigqueue = &p->p_sigqueue; 2324 } else 2325 sigqueue = &td->td_sigqueue; 2326 2327 SDT_PROBE3(proc, , , signal__send, td, p, sig); 2328 2329 /* 2330 * If the signal is being ignored, then we forget about it 2331 * immediately, except when the target process executes 2332 * sigwait(). (Note: we don't set SIGCONT in ps_sigignore, 2333 * and if it is set to SIG_IGN, action will be SIG_DFL here.) 2334 */ 2335 mtx_lock(&ps->ps_mtx); 2336 if (SIGISMEMBER(ps->ps_sigignore, sig)) { 2337 if (kern_sig_discard_ign && 2338 (p->p_sysent->sv_flags & SV_SIG_DISCIGN) == 0) { 2339 SDT_PROBE3(proc, , , signal__discard, td, p, sig); 2340 2341 mtx_unlock(&ps->ps_mtx); 2342 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0) 2343 ksiginfo_tryfree(ksi); 2344 return (0); 2345 } else { 2346 action = SIG_CATCH; 2347 intrval = 0; 2348 } 2349 } else { 2350 if (SIGISMEMBER(td->td_sigmask, sig)) 2351 action = SIG_HOLD; 2352 else if (SIGISMEMBER(ps->ps_sigcatch, sig)) 2353 action = SIG_CATCH; 2354 else 2355 action = SIG_DFL; 2356 if (SIGISMEMBER(ps->ps_sigintr, sig)) 2357 intrval = EINTR; 2358 else 2359 intrval = ERESTART; 2360 } 2361 mtx_unlock(&ps->ps_mtx); 2362 2363 if (prop & SIGPROP_CONT) 2364 sigqueue_delete_stopmask_proc(p); 2365 else if (prop & SIGPROP_STOP) { 2366 /* 2367 * If sending a tty stop signal to a member of an orphaned 2368 * process group, discard the signal here if the action 2369 * is default; don't stop the process below if sleeping, 2370 * and don't clear any pending SIGCONT. 2371 */ 2372 if ((prop & SIGPROP_TTYSTOP) != 0 && 2373 (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 && 2374 action == SIG_DFL) { 2375 if (ksi != NULL && (ksi->ksi_flags & KSI_INS) != 0) 2376 ksiginfo_tryfree(ksi); 2377 return (0); 2378 } 2379 sigqueue_delete_proc(p, SIGCONT); 2380 if (p->p_flag & P_CONTINUED) { 2381 p->p_flag &= ~P_CONTINUED; 2382 PROC_LOCK(p->p_pptr); 2383 sigqueue_take(p->p_ksi); 2384 PROC_UNLOCK(p->p_pptr); 2385 } 2386 } 2387 2388 ret = sigqueue_add(sigqueue, sig, ksi); 2389 if (ret != 0) 2390 return (ret); 2391 signotify(td); 2392 /* 2393 * Defer further processing for signals which are held, 2394 * except that stopped processes must be continued by SIGCONT. 2395 */ 2396 if (action == SIG_HOLD && 2397 !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG))) 2398 return (0); 2399 2400 /* 2401 * Some signals have a process-wide effect and a per-thread 2402 * component. Most processing occurs when the process next 2403 * tries to cross the user boundary, however there are some 2404 * times when processing needs to be done immediately, such as 2405 * waking up threads so that they can cross the user boundary. 2406 * We try to do the per-process part here. 2407 */ 2408 if (P_SHOULDSTOP(p)) { 2409 KASSERT(!(p->p_flag & P_WEXIT), 2410 ("signal to stopped but exiting process")); 2411 if (sig == SIGKILL) { 2412 /* 2413 * If traced process is already stopped, 2414 * then no further action is necessary. 2415 */ 2416 if (p->p_flag & P_TRACED) 2417 return (0); 2418 /* 2419 * SIGKILL sets process running. 2420 * It will die elsewhere. 2421 * All threads must be restarted. 2422 */ 2423 p->p_flag &= ~P_STOPPED_SIG; 2424 goto runfast; 2425 } 2426 2427 if (prop & SIGPROP_CONT) { 2428 /* 2429 * If traced process is already stopped, 2430 * then no further action is necessary. 2431 */ 2432 if (p->p_flag & P_TRACED) 2433 return (0); 2434 /* 2435 * If SIGCONT is default (or ignored), we continue the 2436 * process but don't leave the signal in sigqueue as 2437 * it has no further action. If SIGCONT is held, we 2438 * continue the process and leave the signal in 2439 * sigqueue. If the process catches SIGCONT, let it 2440 * handle the signal itself. If it isn't waiting on 2441 * an event, it goes back to run state. 2442 * Otherwise, process goes back to sleep state. 2443 */ 2444 p->p_flag &= ~P_STOPPED_SIG; 2445 PROC_SLOCK(p); 2446 if (p->p_numthreads == p->p_suspcount) { 2447 PROC_SUNLOCK(p); 2448 p->p_flag |= P_CONTINUED; 2449 p->p_xsig = SIGCONT; 2450 PROC_LOCK(p->p_pptr); 2451 childproc_continued(p); 2452 PROC_UNLOCK(p->p_pptr); 2453 PROC_SLOCK(p); 2454 } 2455 if (action == SIG_DFL) { 2456 thread_unsuspend(p); 2457 PROC_SUNLOCK(p); 2458 sigqueue_delete(sigqueue, sig); 2459 goto out_cont; 2460 } 2461 if (action == SIG_CATCH) { 2462 /* 2463 * The process wants to catch it so it needs 2464 * to run at least one thread, but which one? 2465 */ 2466 PROC_SUNLOCK(p); 2467 goto runfast; 2468 } 2469 /* 2470 * The signal is not ignored or caught. 2471 */ 2472 thread_unsuspend(p); 2473 PROC_SUNLOCK(p); 2474 goto out_cont; 2475 } 2476 2477 if (prop & SIGPROP_STOP) { 2478 /* 2479 * If traced process is already stopped, 2480 * then no further action is necessary. 2481 */ 2482 if (p->p_flag & P_TRACED) 2483 return (0); 2484 /* 2485 * Already stopped, don't need to stop again 2486 * (If we did the shell could get confused). 2487 * Just make sure the signal STOP bit set. 2488 */ 2489 p->p_flag |= P_STOPPED_SIG; 2490 sigqueue_delete(sigqueue, sig); 2491 return (0); 2492 } 2493 2494 /* 2495 * All other kinds of signals: 2496 * If a thread is sleeping interruptibly, simulate a 2497 * wakeup so that when it is continued it will be made 2498 * runnable and can look at the signal. However, don't make 2499 * the PROCESS runnable, leave it stopped. 2500 * It may run a bit until it hits a thread_suspend_check(). 2501 */ 2502 PROC_SLOCK(p); 2503 thread_lock(td); 2504 if (TD_CAN_ABORT(td)) 2505 sig_sleepq_abort(td, intrval); 2506 else 2507 thread_unlock(td); 2508 PROC_SUNLOCK(p); 2509 return (0); 2510 /* 2511 * Mutexes are short lived. Threads waiting on them will 2512 * hit thread_suspend_check() soon. 2513 */ 2514 } else if (p->p_state == PRS_NORMAL) { 2515 if (p->p_flag & P_TRACED || action == SIG_CATCH) { 2516 tdsigwakeup(td, sig, action, intrval); 2517 return (0); 2518 } 2519 2520 MPASS(action == SIG_DFL); 2521 2522 if (prop & SIGPROP_STOP) { 2523 if (p->p_flag & (P_PPWAIT|P_WEXIT)) 2524 return (0); 2525 p->p_flag |= P_STOPPED_SIG; 2526 p->p_xsig = sig; 2527 PROC_SLOCK(p); 2528 sig_suspend_threads(td, p); 2529 if (p->p_numthreads == p->p_suspcount) { 2530 /* 2531 * only thread sending signal to another 2532 * process can reach here, if thread is sending 2533 * signal to its process, because thread does 2534 * not suspend itself here, p_numthreads 2535 * should never be equal to p_suspcount. 2536 */ 2537 thread_stopped(p); 2538 PROC_SUNLOCK(p); 2539 sigqueue_delete_proc(p, p->p_xsig); 2540 } else 2541 PROC_SUNLOCK(p); 2542 return (0); 2543 } 2544 } else { 2545 /* Not in "NORMAL" state. discard the signal. */ 2546 sigqueue_delete(sigqueue, sig); 2547 return (0); 2548 } 2549 2550 /* 2551 * The process is not stopped so we need to apply the signal to all the 2552 * running threads. 2553 */ 2554 runfast: 2555 tdsigwakeup(td, sig, action, intrval); 2556 PROC_SLOCK(p); 2557 thread_unsuspend(p); 2558 PROC_SUNLOCK(p); 2559 out_cont: 2560 itimer_proc_continue(p); 2561 kqtimer_proc_continue(p); 2562 2563 return (0); 2564 } 2565 2566 /* 2567 * The force of a signal has been directed against a single 2568 * thread. We need to see what we can do about knocking it 2569 * out of any sleep it may be in etc. 2570 */ 2571 static void 2572 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval) 2573 { 2574 struct proc *p = td->td_proc; 2575 int prop; 2576 2577 PROC_LOCK_ASSERT(p, MA_OWNED); 2578 prop = sigprop(sig); 2579 2580 PROC_SLOCK(p); 2581 thread_lock(td); 2582 /* 2583 * Bring the priority of a thread up if we want it to get 2584 * killed in this lifetime. Be careful to avoid bumping the 2585 * priority of the idle thread, since we still allow to signal 2586 * kernel processes. 2587 */ 2588 if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 && 2589 td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2590 sched_prio(td, PUSER); 2591 if (TD_ON_SLEEPQ(td)) { 2592 /* 2593 * If thread is sleeping uninterruptibly 2594 * we can't interrupt the sleep... the signal will 2595 * be noticed when the process returns through 2596 * trap() or syscall(). 2597 */ 2598 if ((td->td_flags & TDF_SINTR) == 0) 2599 goto out; 2600 /* 2601 * If SIGCONT is default (or ignored) and process is 2602 * asleep, we are finished; the process should not 2603 * be awakened. 2604 */ 2605 if ((prop & SIGPROP_CONT) && action == SIG_DFL) { 2606 thread_unlock(td); 2607 PROC_SUNLOCK(p); 2608 sigqueue_delete(&p->p_sigqueue, sig); 2609 /* 2610 * It may be on either list in this state. 2611 * Remove from both for now. 2612 */ 2613 sigqueue_delete(&td->td_sigqueue, sig); 2614 return; 2615 } 2616 2617 /* 2618 * Don't awaken a sleeping thread for SIGSTOP if the 2619 * STOP signal is deferred. 2620 */ 2621 if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY | 2622 TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 2623 goto out; 2624 2625 /* 2626 * Give low priority threads a better chance to run. 2627 */ 2628 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) 2629 sched_prio(td, PUSER); 2630 2631 sig_sleepq_abort(td, intrval); 2632 PROC_SUNLOCK(p); 2633 return; 2634 } 2635 2636 /* 2637 * Other states do nothing with the signal immediately, 2638 * other than kicking ourselves if we are running. 2639 * It will either never be noticed, or noticed very soon. 2640 */ 2641 #ifdef SMP 2642 if (TD_IS_RUNNING(td) && td != curthread) 2643 forward_signal(td); 2644 #endif 2645 2646 out: 2647 PROC_SUNLOCK(p); 2648 thread_unlock(td); 2649 } 2650 2651 static void 2652 ptrace_coredumpreq(struct thread *td, struct proc *p, 2653 struct thr_coredump_req *tcq) 2654 { 2655 void *rl_cookie; 2656 2657 if (p->p_sysent->sv_coredump == NULL) { 2658 tcq->tc_error = ENOSYS; 2659 return; 2660 } 2661 2662 rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX); 2663 tcq->tc_error = p->p_sysent->sv_coredump(td, tcq->tc_vp, 2664 tcq->tc_limit, tcq->tc_flags); 2665 vn_rangelock_unlock(tcq->tc_vp, rl_cookie); 2666 } 2667 2668 static void 2669 ptrace_syscallreq(struct thread *td, struct proc *p, 2670 struct thr_syscall_req *tsr) 2671 { 2672 struct sysentvec *sv; 2673 struct sysent *se; 2674 register_t rv_saved[2]; 2675 int error, nerror; 2676 int sc; 2677 bool audited, sy_thr_static; 2678 2679 sv = p->p_sysent; 2680 if (sv->sv_table == NULL || sv->sv_size < tsr->ts_sa.code) { 2681 tsr->ts_ret.sr_error = ENOSYS; 2682 return; 2683 } 2684 2685 sc = tsr->ts_sa.code; 2686 if (sc == SYS_syscall || sc == SYS___syscall) { 2687 sc = tsr->ts_sa.args[0]; 2688 memmove(&tsr->ts_sa.args[0], &tsr->ts_sa.args[1], 2689 sizeof(register_t) * (tsr->ts_nargs - 1)); 2690 } 2691 2692 tsr->ts_sa.callp = se = &sv->sv_table[sc]; 2693 2694 VM_CNT_INC(v_syscall); 2695 td->td_pticks = 0; 2696 if (__predict_false(td->td_cowgen != atomic_load_int( 2697 &td->td_proc->p_cowgen))) 2698 thread_cow_update(td); 2699 2700 td->td_sa = tsr->ts_sa; 2701 2702 #ifdef CAPABILITY_MODE 2703 if ((se->sy_flags & SYF_CAPENABLED) == 0) { 2704 if (CAP_TRACING(td)) 2705 ktrcapfail(CAPFAIL_SYSCALL, NULL); 2706 if (IN_CAPABILITY_MODE(td)) { 2707 tsr->ts_ret.sr_error = ECAPMODE; 2708 return; 2709 } 2710 } 2711 #endif 2712 2713 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0; 2714 audited = AUDIT_SYSCALL_ENTER(sc, td) != 0; 2715 2716 if (!sy_thr_static) { 2717 error = syscall_thread_enter(td, &se); 2718 sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0; 2719 if (error != 0) { 2720 tsr->ts_ret.sr_error = error; 2721 return; 2722 } 2723 } 2724 2725 rv_saved[0] = td->td_retval[0]; 2726 rv_saved[1] = td->td_retval[1]; 2727 nerror = td->td_errno; 2728 td->td_retval[0] = 0; 2729 td->td_retval[1] = 0; 2730 2731 #ifdef KDTRACE_HOOKS 2732 if (se->sy_entry != 0) 2733 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_ENTRY, 0); 2734 #endif 2735 tsr->ts_ret.sr_error = se->sy_call(td, tsr->ts_sa.args); 2736 #ifdef KDTRACE_HOOKS 2737 if (se->sy_return != 0) 2738 (*systrace_probe_func)(&tsr->ts_sa, SYSTRACE_RETURN, 2739 tsr->ts_ret.sr_error != 0 ? -1 : td->td_retval[0]); 2740 #endif 2741 2742 tsr->ts_ret.sr_retval[0] = td->td_retval[0]; 2743 tsr->ts_ret.sr_retval[1] = td->td_retval[1]; 2744 td->td_retval[0] = rv_saved[0]; 2745 td->td_retval[1] = rv_saved[1]; 2746 td->td_errno = nerror; 2747 2748 if (audited) 2749 AUDIT_SYSCALL_EXIT(error, td); 2750 if (!sy_thr_static) 2751 syscall_thread_exit(td, se); 2752 } 2753 2754 static void 2755 ptrace_remotereq(struct thread *td, int flag) 2756 { 2757 struct proc *p; 2758 2759 MPASS(td == curthread); 2760 p = td->td_proc; 2761 PROC_LOCK_ASSERT(p, MA_OWNED); 2762 if ((td->td_dbgflags & flag) == 0) 2763 return; 2764 KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped")); 2765 KASSERT(td->td_remotereq != NULL, ("td_remotereq is NULL")); 2766 2767 PROC_UNLOCK(p); 2768 switch (flag) { 2769 case TDB_COREDUMPREQ: 2770 ptrace_coredumpreq(td, p, td->td_remotereq); 2771 break; 2772 case TDB_SCREMOTEREQ: 2773 ptrace_syscallreq(td, p, td->td_remotereq); 2774 break; 2775 default: 2776 __unreachable(); 2777 } 2778 PROC_LOCK(p); 2779 2780 MPASS((td->td_dbgflags & flag) != 0); 2781 td->td_dbgflags &= ~flag; 2782 td->td_remotereq = NULL; 2783 wakeup(p); 2784 } 2785 2786 static void 2787 sig_suspend_threads(struct thread *td, struct proc *p) 2788 { 2789 struct thread *td2; 2790 2791 PROC_LOCK_ASSERT(p, MA_OWNED); 2792 PROC_SLOCK_ASSERT(p, MA_OWNED); 2793 2794 FOREACH_THREAD_IN_PROC(p, td2) { 2795 thread_lock(td2); 2796 ast_sched_locked(td2, TDA_SUSPEND); 2797 if (TD_IS_SLEEPING(td2) && (td2->td_flags & TDF_SINTR) != 0) { 2798 if (td2->td_flags & TDF_SBDRY) { 2799 /* 2800 * Once a thread is asleep with 2801 * TDF_SBDRY and without TDF_SERESTART 2802 * or TDF_SEINTR set, it should never 2803 * become suspended due to this check. 2804 */ 2805 KASSERT(!TD_IS_SUSPENDED(td2), 2806 ("thread with deferred stops suspended")); 2807 if (TD_SBDRY_INTR(td2)) { 2808 sleepq_abort(td2, TD_SBDRY_ERRNO(td2)); 2809 continue; 2810 } 2811 } else if (!TD_IS_SUSPENDED(td2)) 2812 thread_suspend_one(td2); 2813 } else if (!TD_IS_SUSPENDED(td2)) { 2814 #ifdef SMP 2815 if (TD_IS_RUNNING(td2) && td2 != td) 2816 forward_signal(td2); 2817 #endif 2818 } 2819 thread_unlock(td2); 2820 } 2821 } 2822 2823 /* 2824 * Stop the process for an event deemed interesting to the debugger. If si is 2825 * non-NULL, this is a signal exchange; the new signal requested by the 2826 * debugger will be returned for handling. If si is NULL, this is some other 2827 * type of interesting event. The debugger may request a signal be delivered in 2828 * that case as well, however it will be deferred until it can be handled. 2829 */ 2830 int 2831 ptracestop(struct thread *td, int sig, ksiginfo_t *si) 2832 { 2833 struct proc *p = td->td_proc; 2834 struct thread *td2; 2835 ksiginfo_t ksi; 2836 2837 PROC_LOCK_ASSERT(p, MA_OWNED); 2838 KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); 2839 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 2840 &p->p_mtx.lock_object, "Stopping for traced signal"); 2841 2842 td->td_xsig = sig; 2843 2844 if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) { 2845 td->td_dbgflags |= TDB_XSIG; 2846 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d", 2847 td->td_tid, p->p_pid, td->td_dbgflags, sig); 2848 PROC_SLOCK(p); 2849 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) { 2850 if (P_KILLED(p)) { 2851 /* 2852 * Ensure that, if we've been PT_KILLed, the 2853 * exit status reflects that. Another thread 2854 * may also be in ptracestop(), having just 2855 * received the SIGKILL, but this thread was 2856 * unsuspended first. 2857 */ 2858 td->td_dbgflags &= ~TDB_XSIG; 2859 td->td_xsig = SIGKILL; 2860 p->p_ptevents = 0; 2861 break; 2862 } 2863 if (p->p_flag & P_SINGLE_EXIT && 2864 !(td->td_dbgflags & TDB_EXIT)) { 2865 /* 2866 * Ignore ptrace stops except for thread exit 2867 * events when the process exits. 2868 */ 2869 td->td_dbgflags &= ~TDB_XSIG; 2870 PROC_SUNLOCK(p); 2871 return (0); 2872 } 2873 2874 /* 2875 * Make wait(2) work. Ensure that right after the 2876 * attach, the thread which was decided to become the 2877 * leader of attach gets reported to the waiter. 2878 * Otherwise, just avoid overwriting another thread's 2879 * assignment to p_xthread. If another thread has 2880 * already set p_xthread, the current thread will get 2881 * a chance to report itself upon the next iteration. 2882 */ 2883 if ((td->td_dbgflags & TDB_FSTP) != 0 || 2884 ((p->p_flag2 & P2_PTRACE_FSTP) == 0 && 2885 p->p_xthread == NULL)) { 2886 p->p_xsig = sig; 2887 p->p_xthread = td; 2888 2889 /* 2890 * If we are on sleepqueue already, 2891 * let sleepqueue code decide if it 2892 * needs to go sleep after attach. 2893 */ 2894 if (td->td_wchan == NULL) 2895 td->td_dbgflags &= ~TDB_FSTP; 2896 2897 p->p_flag2 &= ~P2_PTRACE_FSTP; 2898 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE; 2899 sig_suspend_threads(td, p); 2900 } 2901 if ((td->td_dbgflags & TDB_STOPATFORK) != 0) { 2902 td->td_dbgflags &= ~TDB_STOPATFORK; 2903 } 2904 stopme: 2905 td->td_dbgflags |= TDB_SSWITCH; 2906 thread_suspend_switch(td, p); 2907 td->td_dbgflags &= ~TDB_SSWITCH; 2908 if ((td->td_dbgflags & (TDB_COREDUMPREQ | 2909 TDB_SCREMOTEREQ)) != 0) { 2910 MPASS((td->td_dbgflags & (TDB_COREDUMPREQ | 2911 TDB_SCREMOTEREQ)) != 2912 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ)); 2913 PROC_SUNLOCK(p); 2914 ptrace_remotereq(td, td->td_dbgflags & 2915 (TDB_COREDUMPREQ | TDB_SCREMOTEREQ)); 2916 PROC_SLOCK(p); 2917 goto stopme; 2918 } 2919 if (p->p_xthread == td) 2920 p->p_xthread = NULL; 2921 if (!(p->p_flag & P_TRACED)) 2922 break; 2923 if (td->td_dbgflags & TDB_SUSPEND) { 2924 if (p->p_flag & P_SINGLE_EXIT) 2925 break; 2926 goto stopme; 2927 } 2928 } 2929 PROC_SUNLOCK(p); 2930 } 2931 2932 if (si != NULL && sig == td->td_xsig) { 2933 /* Parent wants us to take the original signal unchanged. */ 2934 si->ksi_flags |= KSI_HEAD; 2935 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0) 2936 si->ksi_signo = 0; 2937 } else if (td->td_xsig != 0) { 2938 /* 2939 * If parent wants us to take a new signal, then it will leave 2940 * it in td->td_xsig; otherwise we just look for signals again. 2941 */ 2942 ksiginfo_init(&ksi); 2943 ksi.ksi_signo = td->td_xsig; 2944 ksi.ksi_flags |= KSI_PTRACE; 2945 td2 = sigtd(p, td->td_xsig, false); 2946 tdsendsignal(p, td2, td->td_xsig, &ksi); 2947 if (td != td2) 2948 return (0); 2949 } 2950 2951 return (td->td_xsig); 2952 } 2953 2954 static void 2955 reschedule_signals(struct proc *p, sigset_t block, int flags) 2956 { 2957 struct sigacts *ps; 2958 struct thread *td; 2959 int sig; 2960 bool fastblk, pslocked; 2961 2962 PROC_LOCK_ASSERT(p, MA_OWNED); 2963 ps = p->p_sigacts; 2964 pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0; 2965 mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED); 2966 if (SIGISEMPTY(p->p_siglist)) 2967 return; 2968 SIGSETAND(block, p->p_siglist); 2969 fastblk = (flags & SIGPROCMASK_FASTBLK) != 0; 2970 SIG_FOREACH(sig, &block) { 2971 td = sigtd(p, sig, fastblk); 2972 2973 /* 2974 * If sigtd() selected us despite sigfastblock is 2975 * blocking, do not activate AST or wake us, to avoid 2976 * loop in AST handler. 2977 */ 2978 if (fastblk && td == curthread) 2979 continue; 2980 2981 signotify(td); 2982 if (!pslocked) 2983 mtx_lock(&ps->ps_mtx); 2984 if (p->p_flag & P_TRACED || 2985 (SIGISMEMBER(ps->ps_sigcatch, sig) && 2986 !SIGISMEMBER(td->td_sigmask, sig))) { 2987 tdsigwakeup(td, sig, SIG_CATCH, 2988 (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : 2989 ERESTART)); 2990 } 2991 if (!pslocked) 2992 mtx_unlock(&ps->ps_mtx); 2993 } 2994 } 2995 2996 void 2997 tdsigcleanup(struct thread *td) 2998 { 2999 struct proc *p; 3000 sigset_t unblocked; 3001 3002 p = td->td_proc; 3003 PROC_LOCK_ASSERT(p, MA_OWNED); 3004 3005 sigqueue_flush(&td->td_sigqueue); 3006 if (p->p_numthreads == 1) 3007 return; 3008 3009 /* 3010 * Since we cannot handle signals, notify signal post code 3011 * about this by filling the sigmask. 3012 * 3013 * Also, if needed, wake up thread(s) that do not block the 3014 * same signals as the exiting thread, since the thread might 3015 * have been selected for delivery and woken up. 3016 */ 3017 SIGFILLSET(unblocked); 3018 SIGSETNAND(unblocked, td->td_sigmask); 3019 SIGFILLSET(td->td_sigmask); 3020 reschedule_signals(p, unblocked, 0); 3021 3022 } 3023 3024 static int 3025 sigdeferstop_curr_flags(int cflags) 3026 { 3027 3028 MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 || 3029 (cflags & TDF_SBDRY) != 0); 3030 return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)); 3031 } 3032 3033 /* 3034 * Defer the delivery of SIGSTOP for the current thread, according to 3035 * the requested mode. Returns previous flags, which must be restored 3036 * by sigallowstop(). 3037 * 3038 * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and 3039 * cleared by the current thread, which allow the lock-less read-only 3040 * accesses below. 3041 */ 3042 int 3043 sigdeferstop_impl(int mode) 3044 { 3045 struct thread *td; 3046 int cflags, nflags; 3047 3048 td = curthread; 3049 cflags = sigdeferstop_curr_flags(td->td_flags); 3050 switch (mode) { 3051 case SIGDEFERSTOP_NOP: 3052 nflags = cflags; 3053 break; 3054 case SIGDEFERSTOP_OFF: 3055 nflags = 0; 3056 break; 3057 case SIGDEFERSTOP_SILENT: 3058 nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART); 3059 break; 3060 case SIGDEFERSTOP_EINTR: 3061 nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART; 3062 break; 3063 case SIGDEFERSTOP_ERESTART: 3064 nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR; 3065 break; 3066 default: 3067 panic("sigdeferstop: invalid mode %x", mode); 3068 break; 3069 } 3070 if (cflags == nflags) 3071 return (SIGDEFERSTOP_VAL_NCHG); 3072 thread_lock(td); 3073 td->td_flags = (td->td_flags & ~cflags) | nflags; 3074 thread_unlock(td); 3075 return (cflags); 3076 } 3077 3078 /* 3079 * Restores the STOP handling mode, typically permitting the delivery 3080 * of SIGSTOP for the current thread. This does not immediately 3081 * suspend if a stop was posted. Instead, the thread will suspend 3082 * either via ast() or a subsequent interruptible sleep. 3083 */ 3084 void 3085 sigallowstop_impl(int prev) 3086 { 3087 struct thread *td; 3088 int cflags; 3089 3090 KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop")); 3091 KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0, 3092 ("sigallowstop: incorrect previous mode %x", prev)); 3093 td = curthread; 3094 cflags = sigdeferstop_curr_flags(td->td_flags); 3095 if (cflags != prev) { 3096 thread_lock(td); 3097 td->td_flags = (td->td_flags & ~cflags) | prev; 3098 thread_unlock(td); 3099 } 3100 } 3101 3102 enum sigstatus { 3103 SIGSTATUS_HANDLE, 3104 SIGSTATUS_HANDLED, 3105 SIGSTATUS_IGNORE, 3106 SIGSTATUS_SBDRY_STOP, 3107 }; 3108 3109 /* 3110 * The thread has signal "sig" pending. Figure out what to do with it: 3111 * 3112 * _HANDLE -> the caller should handle the signal 3113 * _HANDLED -> handled internally, reload pending signal set 3114 * _IGNORE -> ignored, remove from the set of pending signals and try the 3115 * next pending signal 3116 * _SBDRY_STOP -> the signal should stop the thread but this is not 3117 * permitted in the current context 3118 */ 3119 static enum sigstatus 3120 sigprocess(struct thread *td, int sig) 3121 { 3122 struct proc *p; 3123 struct sigacts *ps; 3124 struct sigqueue *queue; 3125 ksiginfo_t ksi; 3126 int prop; 3127 3128 KASSERT(_SIG_VALID(sig), ("%s: invalid signal %d", __func__, sig)); 3129 3130 p = td->td_proc; 3131 ps = p->p_sigacts; 3132 mtx_assert(&ps->ps_mtx, MA_OWNED); 3133 PROC_LOCK_ASSERT(p, MA_OWNED); 3134 3135 /* 3136 * We should allow pending but ignored signals below 3137 * if there is sigwait() active, or P_TRACED was 3138 * on when they were posted. 3139 */ 3140 if (SIGISMEMBER(ps->ps_sigignore, sig) && 3141 (p->p_flag & P_TRACED) == 0 && 3142 (td->td_flags & TDF_SIGWAIT) == 0) { 3143 return (SIGSTATUS_IGNORE); 3144 } 3145 3146 /* 3147 * If the process is going to single-thread mode to prepare 3148 * for exit, there is no sense in delivering any signal 3149 * to usermode. Another important consequence is that 3150 * msleep(..., PCATCH, ...) now is only interruptible by a 3151 * suspend request. 3152 */ 3153 if ((p->p_flag2 & P2_WEXIT) != 0) 3154 return (SIGSTATUS_IGNORE); 3155 3156 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) { 3157 /* 3158 * If traced, always stop. 3159 * Remove old signal from queue before the stop. 3160 * XXX shrug off debugger, it causes siginfo to 3161 * be thrown away. 3162 */ 3163 queue = &td->td_sigqueue; 3164 ksiginfo_init(&ksi); 3165 if (sigqueue_get(queue, sig, &ksi) == 0) { 3166 queue = &p->p_sigqueue; 3167 sigqueue_get(queue, sig, &ksi); 3168 } 3169 td->td_si = ksi.ksi_info; 3170 3171 mtx_unlock(&ps->ps_mtx); 3172 sig = ptracestop(td, sig, &ksi); 3173 mtx_lock(&ps->ps_mtx); 3174 3175 td->td_si.si_signo = 0; 3176 3177 /* 3178 * Keep looking if the debugger discarded or 3179 * replaced the signal. 3180 */ 3181 if (sig == 0) 3182 return (SIGSTATUS_HANDLED); 3183 3184 /* 3185 * If the signal became masked, re-queue it. 3186 */ 3187 if (SIGISMEMBER(td->td_sigmask, sig)) { 3188 ksi.ksi_flags |= KSI_HEAD; 3189 sigqueue_add(&p->p_sigqueue, sig, &ksi); 3190 return (SIGSTATUS_HANDLED); 3191 } 3192 3193 /* 3194 * If the traced bit got turned off, requeue the signal and 3195 * reload the set of pending signals. This ensures that p_sig* 3196 * and p_sigact are consistent. 3197 */ 3198 if ((p->p_flag & P_TRACED) == 0) { 3199 if ((ksi.ksi_flags & KSI_PTRACE) == 0) { 3200 ksi.ksi_flags |= KSI_HEAD; 3201 sigqueue_add(queue, sig, &ksi); 3202 } 3203 return (SIGSTATUS_HANDLED); 3204 } 3205 } 3206 3207 /* 3208 * Decide whether the signal should be returned. 3209 * Return the signal's number, or fall through 3210 * to clear it from the pending mask. 3211 */ 3212 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 3213 case (intptr_t)SIG_DFL: 3214 /* 3215 * Don't take default actions on system processes. 3216 */ 3217 if (p->p_pid <= 1) { 3218 #ifdef DIAGNOSTIC 3219 /* 3220 * Are you sure you want to ignore SIGSEGV 3221 * in init? XXX 3222 */ 3223 printf("Process (pid %lu) got signal %d\n", 3224 (u_long)p->p_pid, sig); 3225 #endif 3226 return (SIGSTATUS_IGNORE); 3227 } 3228 3229 /* 3230 * If there is a pending stop signal to process with 3231 * default action, stop here, then clear the signal. 3232 * Traced or exiting processes should ignore stops. 3233 * Additionally, a member of an orphaned process group 3234 * should ignore tty stops. 3235 */ 3236 prop = sigprop(sig); 3237 if (prop & SIGPROP_STOP) { 3238 mtx_unlock(&ps->ps_mtx); 3239 if ((p->p_flag & (P_TRACED | P_WEXIT | 3240 P_SINGLE_EXIT)) != 0 || ((p->p_pgrp-> 3241 pg_flags & PGRP_ORPHANED) != 0 && 3242 (prop & SIGPROP_TTYSTOP) != 0)) { 3243 mtx_lock(&ps->ps_mtx); 3244 return (SIGSTATUS_IGNORE); 3245 } 3246 if (TD_SBDRY_INTR(td)) { 3247 KASSERT((td->td_flags & TDF_SBDRY) != 0, 3248 ("lost TDF_SBDRY")); 3249 mtx_lock(&ps->ps_mtx); 3250 return (SIGSTATUS_SBDRY_STOP); 3251 } 3252 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, 3253 &p->p_mtx.lock_object, "Catching SIGSTOP"); 3254 sigqueue_delete(&td->td_sigqueue, sig); 3255 sigqueue_delete(&p->p_sigqueue, sig); 3256 p->p_flag |= P_STOPPED_SIG; 3257 p->p_xsig = sig; 3258 PROC_SLOCK(p); 3259 sig_suspend_threads(td, p); 3260 thread_suspend_switch(td, p); 3261 PROC_SUNLOCK(p); 3262 mtx_lock(&ps->ps_mtx); 3263 return (SIGSTATUS_HANDLED); 3264 } else if ((prop & SIGPROP_IGNORE) != 0 && 3265 (td->td_flags & TDF_SIGWAIT) == 0) { 3266 /* 3267 * Default action is to ignore; drop it if 3268 * not in kern_sigtimedwait(). 3269 */ 3270 return (SIGSTATUS_IGNORE); 3271 } else { 3272 return (SIGSTATUS_HANDLE); 3273 } 3274 3275 case (intptr_t)SIG_IGN: 3276 if ((td->td_flags & TDF_SIGWAIT) == 0) 3277 return (SIGSTATUS_IGNORE); 3278 else 3279 return (SIGSTATUS_HANDLE); 3280 3281 default: 3282 /* 3283 * This signal has an action, let postsig() process it. 3284 */ 3285 return (SIGSTATUS_HANDLE); 3286 } 3287 } 3288 3289 /* 3290 * If the current process has received a signal (should be caught or cause 3291 * termination, should interrupt current syscall), return the signal number. 3292 * Stop signals with default action are processed immediately, then cleared; 3293 * they aren't returned. This is checked after each entry to the system for 3294 * a syscall or trap (though this can usually be done without calling 3295 * issignal by checking the pending signal masks in cursig.) The normal call 3296 * sequence is 3297 * 3298 * while (sig = cursig(curthread)) 3299 * postsig(sig); 3300 */ 3301 static int 3302 issignal(struct thread *td) 3303 { 3304 struct proc *p; 3305 sigset_t sigpending; 3306 int sig; 3307 3308 p = td->td_proc; 3309 PROC_LOCK_ASSERT(p, MA_OWNED); 3310 3311 for (;;) { 3312 sigpending = td->td_sigqueue.sq_signals; 3313 SIGSETOR(sigpending, p->p_sigqueue.sq_signals); 3314 SIGSETNAND(sigpending, td->td_sigmask); 3315 3316 if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags & 3317 (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) 3318 SIG_STOPSIGMASK(sigpending); 3319 if (SIGISEMPTY(sigpending)) /* no signal to send */ 3320 return (0); 3321 3322 /* 3323 * Do fast sigblock if requested by usermode. Since 3324 * we do know that there was a signal pending at this 3325 * point, set the FAST_SIGBLOCK_PEND as indicator for 3326 * usermode to perform a dummy call to 3327 * FAST_SIGBLOCK_UNBLOCK, which causes immediate 3328 * delivery of postponed pending signal. 3329 */ 3330 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 3331 if (td->td_sigblock_val != 0) 3332 SIGSETNAND(sigpending, fastblock_mask); 3333 if (SIGISEMPTY(sigpending)) { 3334 td->td_pflags |= TDP_SIGFASTPENDING; 3335 return (0); 3336 } 3337 } 3338 3339 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED && 3340 (p->p_flag2 & P2_PTRACE_FSTP) != 0 && 3341 SIGISMEMBER(sigpending, SIGSTOP)) { 3342 /* 3343 * If debugger just attached, always consume 3344 * SIGSTOP from ptrace(PT_ATTACH) first, to 3345 * execute the debugger attach ritual in 3346 * order. 3347 */ 3348 td->td_dbgflags |= TDB_FSTP; 3349 SIGEMPTYSET(sigpending); 3350 SIGADDSET(sigpending, SIGSTOP); 3351 } 3352 3353 SIG_FOREACH(sig, &sigpending) { 3354 switch (sigprocess(td, sig)) { 3355 case SIGSTATUS_HANDLE: 3356 return (sig); 3357 case SIGSTATUS_HANDLED: 3358 goto next; 3359 case SIGSTATUS_IGNORE: 3360 sigqueue_delete(&td->td_sigqueue, sig); 3361 sigqueue_delete(&p->p_sigqueue, sig); 3362 break; 3363 case SIGSTATUS_SBDRY_STOP: 3364 return (-1); 3365 } 3366 } 3367 next:; 3368 } 3369 } 3370 3371 void 3372 thread_stopped(struct proc *p) 3373 { 3374 int n; 3375 3376 PROC_LOCK_ASSERT(p, MA_OWNED); 3377 PROC_SLOCK_ASSERT(p, MA_OWNED); 3378 n = p->p_suspcount; 3379 if (p == curproc) 3380 n++; 3381 if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) { 3382 PROC_SUNLOCK(p); 3383 p->p_flag &= ~P_WAITED; 3384 PROC_LOCK(p->p_pptr); 3385 childproc_stopped(p, (p->p_flag & P_TRACED) ? 3386 CLD_TRAPPED : CLD_STOPPED); 3387 PROC_UNLOCK(p->p_pptr); 3388 PROC_SLOCK(p); 3389 } 3390 } 3391 3392 /* 3393 * Take the action for the specified signal 3394 * from the current set of pending signals. 3395 */ 3396 int 3397 postsig(int sig) 3398 { 3399 struct thread *td; 3400 struct proc *p; 3401 struct sigacts *ps; 3402 sig_t action; 3403 ksiginfo_t ksi; 3404 sigset_t returnmask; 3405 3406 KASSERT(sig != 0, ("postsig")); 3407 3408 td = curthread; 3409 p = td->td_proc; 3410 PROC_LOCK_ASSERT(p, MA_OWNED); 3411 ps = p->p_sigacts; 3412 mtx_assert(&ps->ps_mtx, MA_OWNED); 3413 ksiginfo_init(&ksi); 3414 if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 && 3415 sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0) 3416 return (0); 3417 ksi.ksi_signo = sig; 3418 if (ksi.ksi_code == SI_TIMER) 3419 itimer_accept(p, ksi.ksi_timerid, &ksi); 3420 action = ps->ps_sigact[_SIG_IDX(sig)]; 3421 #ifdef KTRACE 3422 if (KTRPOINT(td, KTR_PSIG)) 3423 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ? 3424 &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code); 3425 #endif 3426 3427 if (action == SIG_DFL) { 3428 /* 3429 * Default action, where the default is to kill 3430 * the process. (Other cases were ignored above.) 3431 */ 3432 mtx_unlock(&ps->ps_mtx); 3433 proc_td_siginfo_capture(td, &ksi.ksi_info); 3434 sigexit(td, sig); 3435 /* NOTREACHED */ 3436 } else { 3437 /* 3438 * If we get here, the signal must be caught. 3439 */ 3440 KASSERT(action != SIG_IGN, ("postsig action %p", action)); 3441 KASSERT(!SIGISMEMBER(td->td_sigmask, sig), 3442 ("postsig action: blocked sig %d", sig)); 3443 3444 /* 3445 * Set the new mask value and also defer further 3446 * occurrences of this signal. 3447 * 3448 * Special case: user has done a sigsuspend. Here the 3449 * current mask is not of interest, but rather the 3450 * mask from before the sigsuspend is what we want 3451 * restored after the signal processing is completed. 3452 */ 3453 if (td->td_pflags & TDP_OLDMASK) { 3454 returnmask = td->td_oldsigmask; 3455 td->td_pflags &= ~TDP_OLDMASK; 3456 } else 3457 returnmask = td->td_sigmask; 3458 3459 if (p->p_sig == sig) { 3460 p->p_sig = 0; 3461 } 3462 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask); 3463 postsig_done(sig, td, ps); 3464 } 3465 return (1); 3466 } 3467 3468 int 3469 sig_ast_checksusp(struct thread *td) 3470 { 3471 struct proc *p __diagused; 3472 int ret; 3473 3474 p = td->td_proc; 3475 PROC_LOCK_ASSERT(p, MA_OWNED); 3476 3477 if (!td_ast_pending(td, TDA_SUSPEND)) 3478 return (0); 3479 3480 ret = thread_suspend_check(1); 3481 MPASS(ret == 0 || ret == EINTR || ret == ERESTART); 3482 return (ret); 3483 } 3484 3485 int 3486 sig_ast_needsigchk(struct thread *td) 3487 { 3488 struct proc *p; 3489 struct sigacts *ps; 3490 int ret, sig; 3491 3492 p = td->td_proc; 3493 PROC_LOCK_ASSERT(p, MA_OWNED); 3494 3495 if (!td_ast_pending(td, TDA_SIG)) 3496 return (0); 3497 3498 ps = p->p_sigacts; 3499 mtx_lock(&ps->ps_mtx); 3500 sig = cursig(td); 3501 if (sig == -1) { 3502 mtx_unlock(&ps->ps_mtx); 3503 KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY")); 3504 KASSERT(TD_SBDRY_INTR(td), 3505 ("lost TDF_SERESTART of TDF_SEINTR")); 3506 KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) != 3507 (TDF_SEINTR | TDF_SERESTART), 3508 ("both TDF_SEINTR and TDF_SERESTART")); 3509 ret = TD_SBDRY_ERRNO(td); 3510 } else if (sig != 0) { 3511 ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART; 3512 mtx_unlock(&ps->ps_mtx); 3513 } else { 3514 mtx_unlock(&ps->ps_mtx); 3515 ret = 0; 3516 } 3517 3518 /* 3519 * Do not go into sleep if this thread was the ptrace(2) 3520 * attach leader. cursig() consumed SIGSTOP from PT_ATTACH, 3521 * but we usually act on the signal by interrupting sleep, and 3522 * should do that here as well. 3523 */ 3524 if ((td->td_dbgflags & TDB_FSTP) != 0) { 3525 if (ret == 0) 3526 ret = EINTR; 3527 td->td_dbgflags &= ~TDB_FSTP; 3528 } 3529 3530 return (ret); 3531 } 3532 3533 int 3534 sig_intr(void) 3535 { 3536 struct thread *td; 3537 struct proc *p; 3538 int ret; 3539 3540 td = curthread; 3541 if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND)) 3542 return (0); 3543 3544 p = td->td_proc; 3545 3546 PROC_LOCK(p); 3547 ret = sig_ast_checksusp(td); 3548 if (ret == 0) 3549 ret = sig_ast_needsigchk(td); 3550 PROC_UNLOCK(p); 3551 return (ret); 3552 } 3553 3554 bool 3555 curproc_sigkilled(void) 3556 { 3557 struct thread *td; 3558 struct proc *p; 3559 struct sigacts *ps; 3560 bool res; 3561 3562 td = curthread; 3563 if (!td_ast_pending(td, TDA_SIG)) 3564 return (false); 3565 3566 p = td->td_proc; 3567 PROC_LOCK(p); 3568 ps = p->p_sigacts; 3569 mtx_lock(&ps->ps_mtx); 3570 res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) || 3571 SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL); 3572 mtx_unlock(&ps->ps_mtx); 3573 PROC_UNLOCK(p); 3574 return (res); 3575 } 3576 3577 void 3578 proc_wkilled(struct proc *p) 3579 { 3580 3581 PROC_LOCK_ASSERT(p, MA_OWNED); 3582 if ((p->p_flag & P_WKILLED) == 0) 3583 p->p_flag |= P_WKILLED; 3584 } 3585 3586 /* 3587 * Kill the current process for stated reason. 3588 */ 3589 void 3590 killproc(struct proc *p, const char *why) 3591 { 3592 3593 PROC_LOCK_ASSERT(p, MA_OWNED); 3594 CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid, 3595 p->p_comm); 3596 log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n", 3597 p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id, 3598 p->p_ucred->cr_uid, why); 3599 proc_wkilled(p); 3600 kern_psignal(p, SIGKILL); 3601 } 3602 3603 /* 3604 * Force the current process to exit with the specified signal, dumping core 3605 * if appropriate. We bypass the normal tests for masked and caught signals, 3606 * allowing unrecoverable failures to terminate the process without changing 3607 * signal state. Mark the accounting record with the signal termination. 3608 * If dumping core, save the signal number for the debugger. Calls exit and 3609 * does not return. 3610 */ 3611 void 3612 sigexit(struct thread *td, int sig) 3613 { 3614 struct proc *p = td->td_proc; 3615 const char *coreinfo; 3616 int rv; 3617 bool logexit; 3618 3619 PROC_LOCK_ASSERT(p, MA_OWNED); 3620 proc_set_p2_wexit(p); 3621 3622 p->p_acflag |= AXSIG; 3623 if ((p->p_flag2 & P2_LOGSIGEXIT_CTL) == 0) 3624 logexit = kern_logsigexit != 0; 3625 else 3626 logexit = (p->p_flag2 & P2_LOGSIGEXIT_ENABLE) != 0; 3627 3628 /* 3629 * We must be single-threading to generate a core dump. This 3630 * ensures that the registers in the core file are up-to-date. 3631 * Also, the ELF dump handler assumes that the thread list doesn't 3632 * change out from under it. 3633 * 3634 * XXX If another thread attempts to single-thread before us 3635 * (e.g. via fork()), we won't get a dump at all. 3636 */ 3637 if ((sigprop(sig) & SIGPROP_CORE) && 3638 thread_single(p, SINGLE_NO_EXIT) == 0) { 3639 p->p_sig = sig; 3640 /* 3641 * Log signals which would cause core dumps 3642 * (Log as LOG_INFO to appease those who don't want 3643 * these messages.) 3644 * XXX : Todo, as well as euid, write out ruid too 3645 * Note that coredump() drops proc lock. 3646 */ 3647 rv = coredump(td); 3648 switch (rv) { 3649 case 0: 3650 sig |= WCOREFLAG; 3651 coreinfo = " (core dumped)"; 3652 break; 3653 case EFAULT: 3654 coreinfo = " (no core dump - bad address)"; 3655 break; 3656 case EINVAL: 3657 coreinfo = " (no core dump - invalid argument)"; 3658 break; 3659 case EFBIG: 3660 coreinfo = " (no core dump - too large)"; 3661 break; 3662 default: 3663 coreinfo = " (no core dump - other error)"; 3664 break; 3665 } 3666 if (logexit) 3667 log(LOG_INFO, 3668 "pid %d (%s), jid %d, uid %d: exited on " 3669 "signal %d%s\n", p->p_pid, p->p_comm, 3670 p->p_ucred->cr_prison->pr_id, 3671 td->td_ucred->cr_uid, 3672 sig &~ WCOREFLAG, coreinfo); 3673 } else 3674 PROC_UNLOCK(p); 3675 exit1(td, 0, sig); 3676 /* NOTREACHED */ 3677 } 3678 3679 /* 3680 * Send queued SIGCHLD to parent when child process's state 3681 * is changed. 3682 */ 3683 static void 3684 sigparent(struct proc *p, int reason, int status) 3685 { 3686 PROC_LOCK_ASSERT(p, MA_OWNED); 3687 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3688 3689 if (p->p_ksi != NULL) { 3690 p->p_ksi->ksi_signo = SIGCHLD; 3691 p->p_ksi->ksi_code = reason; 3692 p->p_ksi->ksi_status = status; 3693 p->p_ksi->ksi_pid = p->p_pid; 3694 p->p_ksi->ksi_uid = p->p_ucred->cr_ruid; 3695 if (KSI_ONQ(p->p_ksi)) 3696 return; 3697 } 3698 pksignal(p->p_pptr, SIGCHLD, p->p_ksi); 3699 } 3700 3701 static void 3702 childproc_jobstate(struct proc *p, int reason, int sig) 3703 { 3704 struct sigacts *ps; 3705 3706 PROC_LOCK_ASSERT(p, MA_OWNED); 3707 PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); 3708 3709 /* 3710 * Wake up parent sleeping in kern_wait(), also send 3711 * SIGCHLD to parent, but SIGCHLD does not guarantee 3712 * that parent will awake, because parent may masked 3713 * the signal. 3714 */ 3715 p->p_pptr->p_flag |= P_STATCHILD; 3716 wakeup(p->p_pptr); 3717 3718 ps = p->p_pptr->p_sigacts; 3719 mtx_lock(&ps->ps_mtx); 3720 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) { 3721 mtx_unlock(&ps->ps_mtx); 3722 sigparent(p, reason, sig); 3723 } else 3724 mtx_unlock(&ps->ps_mtx); 3725 } 3726 3727 void 3728 childproc_stopped(struct proc *p, int reason) 3729 { 3730 3731 childproc_jobstate(p, reason, p->p_xsig); 3732 } 3733 3734 void 3735 childproc_continued(struct proc *p) 3736 { 3737 childproc_jobstate(p, CLD_CONTINUED, SIGCONT); 3738 } 3739 3740 void 3741 childproc_exited(struct proc *p) 3742 { 3743 int reason, status; 3744 3745 if (WCOREDUMP(p->p_xsig)) { 3746 reason = CLD_DUMPED; 3747 status = WTERMSIG(p->p_xsig); 3748 } else if (WIFSIGNALED(p->p_xsig)) { 3749 reason = CLD_KILLED; 3750 status = WTERMSIG(p->p_xsig); 3751 } else { 3752 reason = CLD_EXITED; 3753 status = p->p_xexit; 3754 } 3755 /* 3756 * XXX avoid calling wakeup(p->p_pptr), the work is 3757 * done in exit1(). 3758 */ 3759 sigparent(p, reason, status); 3760 } 3761 3762 #define MAX_NUM_CORE_FILES 100000 3763 #ifndef NUM_CORE_FILES 3764 #define NUM_CORE_FILES 5 3765 #endif 3766 CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES); 3767 static int num_cores = NUM_CORE_FILES; 3768 3769 static int 3770 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS) 3771 { 3772 int error; 3773 int new_val; 3774 3775 new_val = num_cores; 3776 error = sysctl_handle_int(oidp, &new_val, 0, req); 3777 if (error != 0 || req->newptr == NULL) 3778 return (error); 3779 if (new_val > MAX_NUM_CORE_FILES) 3780 new_val = MAX_NUM_CORE_FILES; 3781 if (new_val < 0) 3782 new_val = 0; 3783 num_cores = new_val; 3784 return (0); 3785 } 3786 SYSCTL_PROC(_debug, OID_AUTO, ncores, 3787 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int), 3788 sysctl_debug_num_cores_check, "I", 3789 "Maximum number of generated process corefiles while using index format"); 3790 3791 #define GZIP_SUFFIX ".gz" 3792 #define ZSTD_SUFFIX ".zst" 3793 3794 int compress_user_cores = 0; 3795 3796 static int 3797 sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS) 3798 { 3799 int error, val; 3800 3801 val = compress_user_cores; 3802 error = sysctl_handle_int(oidp, &val, 0, req); 3803 if (error != 0 || req->newptr == NULL) 3804 return (error); 3805 if (val != 0 && !compressor_avail(val)) 3806 return (EINVAL); 3807 compress_user_cores = val; 3808 return (error); 3809 } 3810 SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores, 3811 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int), 3812 sysctl_compress_user_cores, "I", 3813 "Enable compression of user corefiles (" 3814 __XSTRING(COMPRESS_GZIP) " = gzip, " 3815 __XSTRING(COMPRESS_ZSTD) " = zstd)"); 3816 3817 int compress_user_cores_level = 6; 3818 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN, 3819 &compress_user_cores_level, 0, 3820 "Corefile compression level"); 3821 3822 /* 3823 * Protect the access to corefilename[] by allproc_lock. 3824 */ 3825 #define corefilename_lock allproc_lock 3826 3827 static char corefilename[MAXPATHLEN] = {"%N.core"}; 3828 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename)); 3829 3830 static int 3831 sysctl_kern_corefile(SYSCTL_HANDLER_ARGS) 3832 { 3833 int error; 3834 3835 sx_xlock(&corefilename_lock); 3836 error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename), 3837 req); 3838 sx_xunlock(&corefilename_lock); 3839 3840 return (error); 3841 } 3842 SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW | 3843 CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", 3844 "Process corefile name format string"); 3845 3846 static void 3847 vnode_close_locked(struct thread *td, struct vnode *vp) 3848 { 3849 3850 VOP_UNLOCK(vp); 3851 vn_close(vp, FWRITE, td->td_ucred, td); 3852 } 3853 3854 /* 3855 * If the core format has a %I in it, then we need to check 3856 * for existing corefiles before defining a name. 3857 * To do this we iterate over 0..ncores to find a 3858 * non-existing core file name to use. If all core files are 3859 * already used we choose the oldest one. 3860 */ 3861 static int 3862 corefile_open_last(struct thread *td, char *name, int indexpos, 3863 int indexlen, int ncores, struct vnode **vpp) 3864 { 3865 struct vnode *oldvp, *nextvp, *vp; 3866 struct vattr vattr; 3867 struct nameidata nd; 3868 int error, i, flags, oflags, cmode; 3869 char ch; 3870 struct timespec lasttime; 3871 3872 nextvp = oldvp = NULL; 3873 cmode = S_IRUSR | S_IWUSR; 3874 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 3875 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 3876 3877 for (i = 0; i < ncores; i++) { 3878 flags = O_CREAT | FWRITE | O_NOFOLLOW; 3879 3880 ch = name[indexpos + indexlen]; 3881 (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen, 3882 i); 3883 name[indexpos + indexlen] = ch; 3884 3885 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); 3886 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 3887 NULL); 3888 if (error != 0) 3889 break; 3890 3891 vp = nd.ni_vp; 3892 NDFREE_PNBUF(&nd); 3893 if ((flags & O_CREAT) == O_CREAT) { 3894 nextvp = vp; 3895 break; 3896 } 3897 3898 error = VOP_GETATTR(vp, &vattr, td->td_ucred); 3899 if (error != 0) { 3900 vnode_close_locked(td, vp); 3901 break; 3902 } 3903 3904 if (oldvp == NULL || 3905 lasttime.tv_sec > vattr.va_mtime.tv_sec || 3906 (lasttime.tv_sec == vattr.va_mtime.tv_sec && 3907 lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) { 3908 if (oldvp != NULL) 3909 vn_close(oldvp, FWRITE, td->td_ucred, td); 3910 oldvp = vp; 3911 VOP_UNLOCK(oldvp); 3912 lasttime = vattr.va_mtime; 3913 } else { 3914 vnode_close_locked(td, vp); 3915 } 3916 } 3917 3918 if (oldvp != NULL) { 3919 if (nextvp == NULL) { 3920 if ((td->td_proc->p_flag & P_SUGID) != 0) { 3921 error = EFAULT; 3922 vn_close(oldvp, FWRITE, td->td_ucred, td); 3923 } else { 3924 nextvp = oldvp; 3925 error = vn_lock(nextvp, LK_EXCLUSIVE); 3926 if (error != 0) { 3927 vn_close(nextvp, FWRITE, td->td_ucred, 3928 td); 3929 nextvp = NULL; 3930 } 3931 } 3932 } else { 3933 vn_close(oldvp, FWRITE, td->td_ucred, td); 3934 } 3935 } 3936 if (error != 0) { 3937 if (nextvp != NULL) 3938 vnode_close_locked(td, oldvp); 3939 } else { 3940 *vpp = nextvp; 3941 } 3942 3943 return (error); 3944 } 3945 3946 /* 3947 * corefile_open(comm, uid, pid, td, compress, vpp, namep) 3948 * Expand the name described in corefilename, using name, uid, and pid 3949 * and open/create core file. 3950 * corefilename is a printf-like string, with three format specifiers: 3951 * %N name of process ("name") 3952 * %P process id (pid) 3953 * %U user id (uid) 3954 * For example, "%N.core" is the default; they can be disabled completely 3955 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 3956 * This is controlled by the sysctl variable kern.corefile (see above). 3957 */ 3958 static int 3959 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, 3960 int compress, int signum, struct vnode **vpp, char **namep) 3961 { 3962 struct sbuf sb; 3963 struct nameidata nd; 3964 const char *format; 3965 char *hostname, *name; 3966 int cmode, error, flags, i, indexpos, indexlen, oflags, ncores; 3967 3968 hostname = NULL; 3969 format = corefilename; 3970 name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO); 3971 indexlen = 0; 3972 indexpos = -1; 3973 ncores = num_cores; 3974 (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN); 3975 sx_slock(&corefilename_lock); 3976 for (i = 0; format[i] != '\0'; i++) { 3977 switch (format[i]) { 3978 case '%': /* Format character */ 3979 i++; 3980 switch (format[i]) { 3981 case '%': 3982 sbuf_putc(&sb, '%'); 3983 break; 3984 case 'H': /* hostname */ 3985 if (hostname == NULL) { 3986 hostname = malloc(MAXHOSTNAMELEN, 3987 M_TEMP, M_WAITOK); 3988 } 3989 getcredhostname(td->td_ucred, hostname, 3990 MAXHOSTNAMELEN); 3991 sbuf_cat(&sb, hostname); 3992 break; 3993 case 'I': /* autoincrementing index */ 3994 if (indexpos != -1) { 3995 sbuf_printf(&sb, "%%I"); 3996 break; 3997 } 3998 3999 indexpos = sbuf_len(&sb); 4000 sbuf_printf(&sb, "%u", ncores - 1); 4001 indexlen = sbuf_len(&sb) - indexpos; 4002 break; 4003 case 'N': /* process name */ 4004 sbuf_printf(&sb, "%s", comm); 4005 break; 4006 case 'P': /* process id */ 4007 sbuf_printf(&sb, "%u", pid); 4008 break; 4009 case 'S': /* signal number */ 4010 sbuf_printf(&sb, "%i", signum); 4011 break; 4012 case 'U': /* user id */ 4013 sbuf_printf(&sb, "%u", uid); 4014 break; 4015 default: 4016 log(LOG_ERR, 4017 "Unknown format character %c in " 4018 "corename `%s'\n", format[i], format); 4019 break; 4020 } 4021 break; 4022 default: 4023 sbuf_putc(&sb, format[i]); 4024 break; 4025 } 4026 } 4027 sx_sunlock(&corefilename_lock); 4028 free(hostname, M_TEMP); 4029 if (compress == COMPRESS_GZIP) 4030 sbuf_cat(&sb, GZIP_SUFFIX); 4031 else if (compress == COMPRESS_ZSTD) 4032 sbuf_cat(&sb, ZSTD_SUFFIX); 4033 if (sbuf_error(&sb) != 0) { 4034 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too " 4035 "long\n", (long)pid, comm, (u_long)uid); 4036 sbuf_delete(&sb); 4037 free(name, M_TEMP); 4038 return (ENOMEM); 4039 } 4040 sbuf_finish(&sb); 4041 sbuf_delete(&sb); 4042 4043 if (indexpos != -1) { 4044 error = corefile_open_last(td, name, indexpos, indexlen, ncores, 4045 vpp); 4046 if (error != 0) { 4047 log(LOG_ERR, 4048 "pid %d (%s), uid (%u): Path `%s' failed " 4049 "on initial open test, error = %d\n", 4050 pid, comm, uid, name, error); 4051 } 4052 } else { 4053 cmode = S_IRUSR | S_IWUSR; 4054 oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | 4055 (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); 4056 flags = O_CREAT | FWRITE | O_NOFOLLOW; 4057 if ((td->td_proc->p_flag & P_SUGID) != 0) 4058 flags |= O_EXCL; 4059 4060 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); 4061 error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, 4062 NULL); 4063 if (error == 0) { 4064 *vpp = nd.ni_vp; 4065 NDFREE_PNBUF(&nd); 4066 } 4067 } 4068 4069 if (error != 0) { 4070 #ifdef AUDIT 4071 audit_proc_coredump(td, name, error); 4072 #endif 4073 free(name, M_TEMP); 4074 return (error); 4075 } 4076 *namep = name; 4077 return (0); 4078 } 4079 4080 /* 4081 * Dump a process' core. The main routine does some 4082 * policy checking, and creates the name of the coredump; 4083 * then it passes on a vnode and a size limit to the process-specific 4084 * coredump routine if there is one; if there _is not_ one, it returns 4085 * ENOSYS; otherwise it returns the error from the process-specific routine. 4086 */ 4087 4088 static int 4089 coredump(struct thread *td) 4090 { 4091 struct proc *p = td->td_proc; 4092 struct ucred *cred = td->td_ucred; 4093 struct vnode *vp; 4094 struct flock lf; 4095 struct vattr vattr; 4096 size_t fullpathsize; 4097 int error, error1, locked; 4098 char *name; /* name of corefile */ 4099 void *rl_cookie; 4100 off_t limit; 4101 char *fullpath, *freepath = NULL; 4102 struct sbuf *sb; 4103 4104 PROC_LOCK_ASSERT(p, MA_OWNED); 4105 MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td); 4106 4107 if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) || 4108 (p->p_flag2 & P2_NOTRACE) != 0) { 4109 PROC_UNLOCK(p); 4110 return (EFAULT); 4111 } 4112 4113 /* 4114 * Note that the bulk of limit checking is done after 4115 * the corefile is created. The exception is if the limit 4116 * for corefiles is 0, in which case we don't bother 4117 * creating the corefile at all. This layout means that 4118 * a corefile is truncated instead of not being created, 4119 * if it is larger than the limit. 4120 */ 4121 limit = (off_t)lim_cur(td, RLIMIT_CORE); 4122 if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) { 4123 PROC_UNLOCK(p); 4124 return (EFBIG); 4125 } 4126 PROC_UNLOCK(p); 4127 4128 error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, 4129 compress_user_cores, p->p_sig, &vp, &name); 4130 if (error != 0) 4131 return (error); 4132 4133 /* 4134 * Don't dump to non-regular files or files with links. 4135 * Do not dump into system files. Effective user must own the corefile. 4136 */ 4137 if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 || 4138 vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 || 4139 vattr.va_uid != cred->cr_uid) { 4140 VOP_UNLOCK(vp); 4141 error = EFAULT; 4142 goto out; 4143 } 4144 4145 VOP_UNLOCK(vp); 4146 4147 /* Postpone other writers, including core dumps of other processes. */ 4148 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 4149 4150 lf.l_whence = SEEK_SET; 4151 lf.l_start = 0; 4152 lf.l_len = 0; 4153 lf.l_type = F_WRLCK; 4154 locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0); 4155 4156 VATTR_NULL(&vattr); 4157 vattr.va_size = 0; 4158 if (set_core_nodump_flag) 4159 vattr.va_flags = UF_NODUMP; 4160 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 4161 VOP_SETATTR(vp, &vattr, cred); 4162 VOP_UNLOCK(vp); 4163 PROC_LOCK(p); 4164 p->p_acflag |= ACORE; 4165 PROC_UNLOCK(p); 4166 4167 if (p->p_sysent->sv_coredump != NULL) { 4168 error = p->p_sysent->sv_coredump(td, vp, limit, 0); 4169 } else { 4170 error = ENOSYS; 4171 } 4172 4173 if (locked) { 4174 lf.l_type = F_UNLCK; 4175 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 4176 } 4177 vn_rangelock_unlock(vp, rl_cookie); 4178 4179 /* 4180 * Notify the userland helper that a process triggered a core dump. 4181 * This allows the helper to run an automated debugging session. 4182 */ 4183 if (error != 0 || coredump_devctl == 0) 4184 goto out; 4185 sb = sbuf_new_auto(); 4186 if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0) 4187 goto out2; 4188 sbuf_cat(sb, "comm=\""); 4189 devctl_safe_quote_sb(sb, fullpath); 4190 free(freepath, M_TEMP); 4191 sbuf_cat(sb, "\" core=\""); 4192 4193 /* 4194 * We can't lookup core file vp directly. When we're replacing a core, and 4195 * other random times, we flush the name cache, so it will fail. Instead, 4196 * if the path of the core is relative, add the current dir in front if it. 4197 */ 4198 if (name[0] != '/') { 4199 fullpathsize = MAXPATHLEN; 4200 freepath = malloc(fullpathsize, M_TEMP, M_WAITOK); 4201 if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) { 4202 free(freepath, M_TEMP); 4203 goto out2; 4204 } 4205 devctl_safe_quote_sb(sb, fullpath); 4206 free(freepath, M_TEMP); 4207 sbuf_putc(sb, '/'); 4208 } 4209 devctl_safe_quote_sb(sb, name); 4210 sbuf_putc(sb, '"'); 4211 if (sbuf_finish(sb) == 0) 4212 devctl_notify("kernel", "signal", "coredump", sbuf_data(sb)); 4213 out2: 4214 sbuf_delete(sb); 4215 out: 4216 error1 = vn_close(vp, FWRITE, cred, td); 4217 if (error == 0) 4218 error = error1; 4219 #ifdef AUDIT 4220 audit_proc_coredump(td, name, error); 4221 #endif 4222 free(name, M_TEMP); 4223 return (error); 4224 } 4225 4226 /* 4227 * Nonexistent system call-- signal process (may want to handle it). Flag 4228 * error in case process won't see signal immediately (blocked or ignored). 4229 */ 4230 #ifndef _SYS_SYSPROTO_H_ 4231 struct nosys_args { 4232 int dummy; 4233 }; 4234 #endif 4235 /* ARGSUSED */ 4236 int 4237 nosys(struct thread *td, struct nosys_args *args) 4238 { 4239 struct proc *p; 4240 4241 p = td->td_proc; 4242 4243 if (SV_PROC_FLAG(p, SV_SIGSYS) != 0 && kern_signosys) { 4244 PROC_LOCK(p); 4245 tdsignal(td, SIGSYS); 4246 PROC_UNLOCK(p); 4247 } 4248 if (kern_lognosys == 1 || kern_lognosys == 3) { 4249 uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 4250 td->td_sa.code); 4251 } 4252 if (kern_lognosys == 2 || kern_lognosys == 3 || 4253 (p->p_pid == 1 && (kern_lognosys & 3) == 0)) { 4254 printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, 4255 td->td_sa.code); 4256 } 4257 return (ENOSYS); 4258 } 4259 4260 /* 4261 * Send a SIGIO or SIGURG signal to a process or process group using stored 4262 * credentials rather than those of the current process. 4263 */ 4264 void 4265 pgsigio(struct sigio **sigiop, int sig, int checkctty) 4266 { 4267 ksiginfo_t ksi; 4268 struct sigio *sigio; 4269 4270 ksiginfo_init(&ksi); 4271 ksi.ksi_signo = sig; 4272 ksi.ksi_code = SI_KERNEL; 4273 4274 SIGIO_LOCK(); 4275 sigio = *sigiop; 4276 if (sigio == NULL) { 4277 SIGIO_UNLOCK(); 4278 return; 4279 } 4280 if (sigio->sio_pgid > 0) { 4281 PROC_LOCK(sigio->sio_proc); 4282 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred)) 4283 kern_psignal(sigio->sio_proc, sig); 4284 PROC_UNLOCK(sigio->sio_proc); 4285 } else if (sigio->sio_pgid < 0) { 4286 struct proc *p; 4287 4288 PGRP_LOCK(sigio->sio_pgrp); 4289 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 4290 PROC_LOCK(p); 4291 if (p->p_state == PRS_NORMAL && 4292 CANSIGIO(sigio->sio_ucred, p->p_ucred) && 4293 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 4294 kern_psignal(p, sig); 4295 PROC_UNLOCK(p); 4296 } 4297 PGRP_UNLOCK(sigio->sio_pgrp); 4298 } 4299 SIGIO_UNLOCK(); 4300 } 4301 4302 static int 4303 filt_sigattach(struct knote *kn) 4304 { 4305 struct proc *p = curproc; 4306 4307 kn->kn_ptr.p_proc = p; 4308 kn->kn_flags |= EV_CLEAR; /* automatically set */ 4309 4310 knlist_add(p->p_klist, kn, 0); 4311 4312 return (0); 4313 } 4314 4315 static void 4316 filt_sigdetach(struct knote *kn) 4317 { 4318 knlist_remove(kn->kn_knlist, kn, 0); 4319 } 4320 4321 /* 4322 * signal knotes are shared with proc knotes, so we apply a mask to 4323 * the hint in order to differentiate them from process hints. This 4324 * could be avoided by using a signal-specific knote list, but probably 4325 * isn't worth the trouble. 4326 */ 4327 static int 4328 filt_signal(struct knote *kn, long hint) 4329 { 4330 4331 if (hint & NOTE_SIGNAL) { 4332 hint &= ~NOTE_SIGNAL; 4333 4334 if (kn->kn_id == hint) 4335 kn->kn_data++; 4336 } 4337 return (kn->kn_data != 0); 4338 } 4339 4340 struct sigacts * 4341 sigacts_alloc(void) 4342 { 4343 struct sigacts *ps; 4344 4345 ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO); 4346 refcount_init(&ps->ps_refcnt, 1); 4347 mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF); 4348 return (ps); 4349 } 4350 4351 void 4352 sigacts_free(struct sigacts *ps) 4353 { 4354 4355 if (refcount_release(&ps->ps_refcnt) == 0) 4356 return; 4357 mtx_destroy(&ps->ps_mtx); 4358 free(ps, M_SUBPROC); 4359 } 4360 4361 struct sigacts * 4362 sigacts_hold(struct sigacts *ps) 4363 { 4364 4365 refcount_acquire(&ps->ps_refcnt); 4366 return (ps); 4367 } 4368 4369 void 4370 sigacts_copy(struct sigacts *dest, struct sigacts *src) 4371 { 4372 4373 KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest")); 4374 mtx_lock(&src->ps_mtx); 4375 bcopy(src, dest, offsetof(struct sigacts, ps_refcnt)); 4376 mtx_unlock(&src->ps_mtx); 4377 } 4378 4379 int 4380 sigacts_shared(struct sigacts *ps) 4381 { 4382 4383 return (ps->ps_refcnt > 1); 4384 } 4385 4386 void 4387 sig_drop_caught(struct proc *p) 4388 { 4389 int sig; 4390 struct sigacts *ps; 4391 4392 ps = p->p_sigacts; 4393 PROC_LOCK_ASSERT(p, MA_OWNED); 4394 mtx_assert(&ps->ps_mtx, MA_OWNED); 4395 SIG_FOREACH(sig, &ps->ps_sigcatch) { 4396 sigdflt(ps, sig); 4397 if ((sigprop(sig) & SIGPROP_IGNORE) != 0) 4398 sigqueue_delete_proc(p, sig); 4399 } 4400 } 4401 4402 static void 4403 sigfastblock_failed(struct thread *td, bool sendsig, bool write) 4404 { 4405 ksiginfo_t ksi; 4406 4407 /* 4408 * Prevent further fetches and SIGSEGVs, allowing thread to 4409 * issue syscalls despite corruption. 4410 */ 4411 sigfastblock_clear(td); 4412 4413 if (!sendsig) 4414 return; 4415 ksiginfo_init_trap(&ksi); 4416 ksi.ksi_signo = SIGSEGV; 4417 ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR; 4418 ksi.ksi_addr = td->td_sigblock_ptr; 4419 trapsignal(td, &ksi); 4420 } 4421 4422 static bool 4423 sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp) 4424 { 4425 uint32_t res; 4426 4427 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4428 return (true); 4429 if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) { 4430 sigfastblock_failed(td, sendsig, false); 4431 return (false); 4432 } 4433 *valp = res; 4434 td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS; 4435 return (true); 4436 } 4437 4438 static void 4439 sigfastblock_resched(struct thread *td, bool resched) 4440 { 4441 struct proc *p; 4442 4443 if (resched) { 4444 p = td->td_proc; 4445 PROC_LOCK(p); 4446 reschedule_signals(p, td->td_sigmask, 0); 4447 PROC_UNLOCK(p); 4448 } 4449 ast_sched(td, TDA_SIG); 4450 } 4451 4452 int 4453 sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap) 4454 { 4455 struct proc *p; 4456 int error, res; 4457 uint32_t oldval; 4458 4459 error = 0; 4460 p = td->td_proc; 4461 switch (uap->cmd) { 4462 case SIGFASTBLOCK_SETPTR: 4463 if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { 4464 error = EBUSY; 4465 break; 4466 } 4467 if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) { 4468 error = EINVAL; 4469 break; 4470 } 4471 td->td_pflags |= TDP_SIGFASTBLOCK; 4472 td->td_sigblock_ptr = uap->ptr; 4473 break; 4474 4475 case SIGFASTBLOCK_UNBLOCK: 4476 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4477 error = EINVAL; 4478 break; 4479 } 4480 4481 for (;;) { 4482 res = casueword32(td->td_sigblock_ptr, 4483 SIGFASTBLOCK_PEND, &oldval, 0); 4484 if (res == -1) { 4485 error = EFAULT; 4486 sigfastblock_failed(td, false, true); 4487 break; 4488 } 4489 if (res == 0) 4490 break; 4491 MPASS(res == 1); 4492 if (oldval != SIGFASTBLOCK_PEND) { 4493 error = EBUSY; 4494 break; 4495 } 4496 error = thread_check_susp(td, false); 4497 if (error != 0) 4498 break; 4499 } 4500 if (error != 0) 4501 break; 4502 4503 /* 4504 * td_sigblock_val is cleared there, but not on a 4505 * syscall exit. The end effect is that a single 4506 * interruptible sleep, while user sigblock word is 4507 * set, might return EINTR or ERESTART to usermode 4508 * without delivering signal. All further sleeps, 4509 * until userspace clears the word and does 4510 * sigfastblock(UNBLOCK), observe current word and no 4511 * longer get interrupted. It is slight 4512 * non-conformance, with alternative to have read the 4513 * sigblock word on each syscall entry. 4514 */ 4515 td->td_sigblock_val = 0; 4516 4517 /* 4518 * Rely on normal ast mechanism to deliver pending 4519 * signals to current thread. But notify others about 4520 * fake unblock. 4521 */ 4522 sigfastblock_resched(td, error == 0 && p->p_numthreads != 1); 4523 4524 break; 4525 4526 case SIGFASTBLOCK_UNSETPTR: 4527 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { 4528 error = EINVAL; 4529 break; 4530 } 4531 if (!sigfastblock_fetch_sig(td, false, &oldval)) { 4532 error = EFAULT; 4533 break; 4534 } 4535 if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) { 4536 error = EBUSY; 4537 break; 4538 } 4539 sigfastblock_clear(td); 4540 break; 4541 4542 default: 4543 error = EINVAL; 4544 break; 4545 } 4546 return (error); 4547 } 4548 4549 void 4550 sigfastblock_clear(struct thread *td) 4551 { 4552 bool resched; 4553 4554 if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) 4555 return; 4556 td->td_sigblock_val = 0; 4557 resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 || 4558 SIGPENDING(td); 4559 td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING); 4560 sigfastblock_resched(td, resched); 4561 } 4562 4563 void 4564 sigfastblock_fetch(struct thread *td) 4565 { 4566 uint32_t val; 4567 4568 (void)sigfastblock_fetch_sig(td, true, &val); 4569 } 4570 4571 static void 4572 sigfastblock_setpend1(struct thread *td) 4573 { 4574 int res; 4575 uint32_t oldval; 4576 4577 if ((td->td_pflags & TDP_SIGFASTPENDING) == 0) 4578 return; 4579 res = fueword32((void *)td->td_sigblock_ptr, &oldval); 4580 if (res == -1) { 4581 sigfastblock_failed(td, true, false); 4582 return; 4583 } 4584 for (;;) { 4585 res = casueword32(td->td_sigblock_ptr, oldval, &oldval, 4586 oldval | SIGFASTBLOCK_PEND); 4587 if (res == -1) { 4588 sigfastblock_failed(td, true, true); 4589 return; 4590 } 4591 if (res == 0) { 4592 td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS; 4593 td->td_pflags &= ~TDP_SIGFASTPENDING; 4594 break; 4595 } 4596 MPASS(res == 1); 4597 if (thread_check_susp(td, false) != 0) 4598 break; 4599 } 4600 } 4601 4602 static void 4603 sigfastblock_setpend(struct thread *td, bool resched) 4604 { 4605 struct proc *p; 4606 4607 sigfastblock_setpend1(td); 4608 if (resched) { 4609 p = td->td_proc; 4610 PROC_LOCK(p); 4611 reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK); 4612 PROC_UNLOCK(p); 4613 } 4614 } 4615