sys_sig.c revision 1.12.10.1
1 /* $NetBSD: sys_sig.c,v 1.12.10.1 2008/05/18 12:35:10 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1982, 1986, 1989, 1991, 1993 34 * The Regents of the University of California. All rights reserved. 35 * (c) UNIX System Laboratories, Inc. 36 * All or some portions of this file are derived from material licensed 37 * to the University of California by American Telephone and Telegraph 38 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 39 * the permission of UNIX System Laboratories, Inc. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 66 */ 67 68 #include <sys/cdefs.h> 69 __KERNEL_RCSID(0, "$NetBSD: sys_sig.c,v 1.12.10.1 2008/05/18 12:35:10 yamt Exp $"); 70 71 #include "opt_ptrace.h" 72 #include "opt_compat_netbsd.h" 73 #include "opt_compat_netbsd32.h" 74 75 #include <sys/param.h> 76 #include <sys/kernel.h> 77 #include <sys/signalvar.h> 78 #include <sys/proc.h> 79 #include <sys/pool.h> 80 #include <sys/syscallargs.h> 81 #include <sys/kauth.h> 82 #include <sys/wait.h> 83 #include <sys/kmem.h> 84 85 #ifdef COMPAT_16 86 /* ARGSUSED */ 87 int 88 compat_16_sys___sigaction14(struct lwp *l, const struct compat_16_sys___sigaction14_args *uap, register_t *retval) 89 { 90 /* { 91 syscallarg(int) signum; 92 syscallarg(const struct sigaction *) nsa; 93 syscallarg(struct sigaction *) osa; 94 } */ 95 struct sigaction nsa, osa; 96 int error; 97 98 if (SCARG(uap, nsa)) { 99 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 100 if (error) 101 return (error); 102 } 103 error = sigaction1(l, SCARG(uap, signum), 104 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 105 NULL, 0); 106 if (error) 107 return (error); 108 if (SCARG(uap, osa)) { 109 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 110 if (error) 111 return (error); 112 } 113 return (0); 114 } 115 #endif 116 117 /* ARGSUSED */ 118 int 119 sys___sigaction_sigtramp(struct lwp *l, const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 120 { 121 /* { 122 syscallarg(int) signum; 123 syscallarg(const struct sigaction *) nsa; 124 syscallarg(struct sigaction *) osa; 125 syscallarg(void *) tramp; 126 syscallarg(int) vers; 127 } */ 128 struct sigaction nsa, osa; 129 int error; 130 131 if (SCARG(uap, nsa)) { 132 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 133 if (error) 134 return (error); 135 } 136 error = sigaction1(l, SCARG(uap, signum), 137 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 138 SCARG(uap, tramp), SCARG(uap, vers)); 139 if (error) 140 return (error); 141 if (SCARG(uap, osa)) { 142 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 143 if (error) 144 return (error); 145 } 146 return (0); 147 } 148 149 /* 150 * Manipulate signal mask. Note that we receive new mask, not pointer, and 151 * return old mask as return value; the library stub does the rest. 152 */ 153 int 154 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, register_t *retval) 155 { 156 /* { 157 syscallarg(int) how; 158 syscallarg(const sigset_t *) set; 159 syscallarg(sigset_t *) oset; 160 } */ 161 struct proc *p = l->l_proc; 162 sigset_t nss, oss; 163 int error; 164 165 if (SCARG(uap, set)) { 166 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 167 if (error) 168 return (error); 169 } 170 mutex_enter(p->p_lock); 171 error = sigprocmask1(l, SCARG(uap, how), 172 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 173 mutex_exit(p->p_lock); 174 if (error) 175 return (error); 176 if (SCARG(uap, oset)) { 177 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 178 if (error) 179 return (error); 180 } 181 return (0); 182 } 183 184 /* ARGSUSED */ 185 int 186 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, register_t *retval) 187 { 188 /* { 189 syscallarg(sigset_t *) set; 190 } */ 191 sigset_t ss; 192 193 sigpending1(l, &ss); 194 return (copyout(&ss, SCARG(uap, set), sizeof(ss))); 195 } 196 197 /* 198 * Suspend process until signal, providing mask to be set in the meantime. 199 * Note nonstandard calling convention: libc stub passes mask, not pointer, 200 * to save a copyin. 201 */ 202 /* ARGSUSED */ 203 int 204 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, register_t *retval) 205 { 206 /* { 207 syscallarg(const sigset_t *) set; 208 } */ 209 sigset_t ss; 210 int error; 211 212 if (SCARG(uap, set)) { 213 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 214 if (error) 215 return (error); 216 } 217 218 return (sigsuspend1(l, SCARG(uap, set) ? &ss : 0)); 219 } 220 221 /* ARGSUSED */ 222 int 223 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, register_t *retval) 224 { 225 /* { 226 syscallarg(const struct sigaltstack *) nss; 227 syscallarg(struct sigaltstack *) oss; 228 } */ 229 struct sigaltstack nss, oss; 230 int error; 231 232 if (SCARG(uap, nss)) { 233 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 234 if (error) 235 return (error); 236 } 237 error = sigaltstack1(l, 238 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 239 if (error) 240 return (error); 241 if (SCARG(uap, oss)) { 242 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 243 if (error) 244 return (error); 245 } 246 return (0); 247 } 248 249 /* ARGSUSED */ 250 int 251 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 252 { 253 /* { 254 syscallarg(int) pid; 255 syscallarg(int) signum; 256 } */ 257 struct proc *p; 258 ksiginfo_t ksi; 259 int signum = SCARG(uap, signum); 260 int error; 261 262 if ((u_int)signum >= NSIG) 263 return (EINVAL); 264 KSI_INIT(&ksi); 265 ksi.ksi_signo = signum; 266 ksi.ksi_code = SI_USER; 267 ksi.ksi_pid = l->l_proc->p_pid; 268 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 269 if (SCARG(uap, pid) > 0) { 270 /* kill single process */ 271 mutex_enter(proc_lock); 272 if ((p = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) { 273 mutex_exit(proc_lock); 274 return (ESRCH); 275 } 276 mutex_enter(p->p_lock); 277 error = kauth_authorize_process(l->l_cred, 278 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signum), 279 NULL, NULL); 280 if (!error && signum) { 281 kpsignal2(p, &ksi); 282 } 283 mutex_exit(p->p_lock); 284 mutex_exit(proc_lock); 285 return (error); 286 } 287 switch (SCARG(uap, pid)) { 288 case -1: /* broadcast signal */ 289 return (killpg1(l, &ksi, 0, 1)); 290 case 0: /* signal own process group */ 291 return (killpg1(l, &ksi, 0, 0)); 292 default: /* negative explicit process group */ 293 return (killpg1(l, &ksi, -SCARG(uap, pid), 0)); 294 } 295 /* NOTREACHED */ 296 } 297 298 /* ARGSUSED */ 299 int 300 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, register_t *retval) 301 { 302 /* { 303 syscallarg(struct __ucontext *) ucp; 304 } */ 305 struct proc *p = l->l_proc; 306 ucontext_t uc; 307 308 mutex_enter(p->p_lock); 309 getucontext(l, &uc); 310 mutex_exit(p->p_lock); 311 312 return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp)))); 313 } 314 315 /* ARGSUSED */ 316 int 317 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, register_t *retval) 318 { 319 /* { 320 syscallarg(const ucontext_t *) ucp; 321 } */ 322 struct proc *p = l->l_proc; 323 ucontext_t uc; 324 int error; 325 326 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 327 if (error) 328 return (error); 329 if (!(uc.uc_flags & _UC_CPU)) 330 return (EINVAL); 331 mutex_enter(p->p_lock); 332 error = setucontext(l, &uc); 333 mutex_exit(p->p_lock); 334 if (error) 335 return (error); 336 337 return (EJUSTRETURN); 338 } 339 340 /* 341 * sigtimedwait(2) system call, used also for implementation 342 * of sigwaitinfo() and sigwait(). 343 * 344 * This only handles single LWP in signal wait. libpthread provides 345 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 346 */ 347 int 348 sys___sigtimedwait(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval) 349 { 350 351 return __sigtimedwait1(l, uap, retval, copyout, copyin, copyout); 352 } 353 354 int 355 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 356 struct sigaction *osa, const void *tramp, int vers) 357 { 358 struct proc *p; 359 struct sigacts *ps; 360 sigset_t tset; 361 int prop, error; 362 ksiginfoq_t kq; 363 364 if (signum <= 0 || signum >= NSIG) 365 return (EINVAL); 366 367 p = l->l_proc; 368 error = 0; 369 ksiginfo_queue_init(&kq); 370 371 /* 372 * Trampoline ABI version 0 is reserved for the legacy kernel 373 * provided on-stack trampoline. Conversely, if we are using a 374 * non-0 ABI version, we must have a trampoline. Only validate the 375 * vers if a new sigaction was supplied. Emulations use legacy 376 * kernel trampolines with version 0, alternatively check for that 377 * too. 378 */ 379 if ((vers != 0 && tramp == NULL) || 380 #ifdef SIGTRAMP_VALID 381 (nsa != NULL && 382 ((vers == 0) ? 383 (p->p_emul->e_sigcode == NULL) : 384 !SIGTRAMP_VALID(vers))) || 385 #endif 386 (vers == 0 && tramp != NULL)) { 387 return (EINVAL); 388 } 389 390 mutex_enter(p->p_lock); 391 392 ps = p->p_sigacts; 393 if (osa) 394 *osa = SIGACTION_PS(ps, signum); 395 if (!nsa) 396 goto out; 397 398 prop = sigprop[signum]; 399 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 400 error = EINVAL; 401 goto out; 402 } 403 404 SIGACTION_PS(ps, signum) = *nsa; 405 ps->sa_sigdesc[signum].sd_tramp = tramp; 406 ps->sa_sigdesc[signum].sd_vers = vers; 407 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 408 409 if ((prop & SA_NORESET) != 0) 410 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 411 412 if (signum == SIGCHLD) { 413 if (nsa->sa_flags & SA_NOCLDSTOP) 414 p->p_sflag |= PS_NOCLDSTOP; 415 else 416 p->p_sflag &= ~PS_NOCLDSTOP; 417 if (nsa->sa_flags & SA_NOCLDWAIT) { 418 /* 419 * Paranoia: since SA_NOCLDWAIT is implemented by 420 * reparenting the dying child to PID 1 (and trust 421 * it to reap the zombie), PID 1 itself is forbidden 422 * to set SA_NOCLDWAIT. 423 */ 424 if (p->p_pid == 1) 425 p->p_flag &= ~PK_NOCLDWAIT; 426 else 427 p->p_flag |= PK_NOCLDWAIT; 428 } else 429 p->p_flag &= ~PK_NOCLDWAIT; 430 431 if (nsa->sa_handler == SIG_IGN) { 432 /* 433 * Paranoia: same as above. 434 */ 435 if (p->p_pid == 1) 436 p->p_flag &= ~PK_CLDSIGIGN; 437 else 438 p->p_flag |= PK_CLDSIGIGN; 439 } else 440 p->p_flag &= ~PK_CLDSIGIGN; 441 } 442 443 if ((nsa->sa_flags & SA_NODEFER) == 0) 444 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 445 else 446 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 447 448 /* 449 * Set bit in p_sigctx.ps_sigignore for signals that are set to 450 * SIG_IGN, and for signals set to SIG_DFL where the default is to 451 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 452 * we have to restart the process. 453 */ 454 if (nsa->sa_handler == SIG_IGN || 455 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 456 /* Never to be seen again. */ 457 sigemptyset(&tset); 458 sigaddset(&tset, signum); 459 sigclearall(p, &tset, &kq); 460 if (signum != SIGCONT) { 461 /* Easier in psignal */ 462 sigaddset(&p->p_sigctx.ps_sigignore, signum); 463 } 464 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 465 } else { 466 sigdelset(&p->p_sigctx.ps_sigignore, signum); 467 if (nsa->sa_handler == SIG_DFL) 468 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 469 else 470 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 471 } 472 473 /* 474 * Previously held signals may now have become visible. Ensure that 475 * we check for them before returning to userspace. 476 */ 477 if (sigispending(l, 0)) { 478 lwp_lock(l); 479 l->l_flag |= LW_PENDSIG; 480 lwp_unlock(l); 481 } 482 out: 483 mutex_exit(p->p_lock); 484 ksiginfo_queue_drain(&kq); 485 486 return (error); 487 } 488 489 int 490 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 491 { 492 int more; 493 494 KASSERT(mutex_owned(l->l_proc->p_lock)); 495 496 if (oss) 497 *oss = l->l_sigmask; 498 if (nss) { 499 switch (how) { 500 case SIG_BLOCK: 501 sigplusset(nss, &l->l_sigmask); 502 more = 0; 503 break; 504 case SIG_UNBLOCK: 505 sigminusset(nss, &l->l_sigmask); 506 more = 1; 507 break; 508 case SIG_SETMASK: 509 l->l_sigmask = *nss; 510 more = 1; 511 break; 512 default: 513 return (EINVAL); 514 } 515 sigminusset(&sigcantmask, &l->l_sigmask); 516 if (more && sigispending(l, 0)) { 517 /* 518 * Check for pending signals on return to user. 519 */ 520 lwp_lock(l); 521 l->l_flag |= LW_PENDSIG; 522 lwp_unlock(l); 523 } 524 } 525 526 return (0); 527 } 528 529 void 530 sigpending1(struct lwp *l, sigset_t *ss) 531 { 532 struct proc *p = l->l_proc; 533 534 mutex_enter(p->p_lock); 535 *ss = l->l_sigpend.sp_set; 536 sigplusset(&p->p_sigpend.sp_set, ss); 537 sigminusset(&l->l_sigmask, ss); 538 mutex_exit(p->p_lock); 539 } 540 541 int 542 sigsuspend1(struct lwp *l, const sigset_t *ss) 543 { 544 struct proc *p; 545 546 p = l->l_proc; 547 548 if (ss) { 549 /* 550 * When returning from sigsuspend, we want 551 * the old mask to be restored after the 552 * signal handler has finished. Thus, we 553 * save it here and mark the sigctx structure 554 * to indicate this. 555 */ 556 mutex_enter(p->p_lock); 557 l->l_sigrestore = 1; 558 l->l_sigoldmask = l->l_sigmask; 559 l->l_sigmask = *ss; 560 sigminusset(&sigcantmask, &l->l_sigmask); 561 562 /* Check for pending signals when sleeping. */ 563 if (sigispending(l, 0)) { 564 lwp_lock(l); 565 l->l_flag |= LW_PENDSIG; 566 lwp_unlock(l); 567 } 568 mutex_exit(p->p_lock); 569 } 570 571 while (kpause("pause", true, 0, NULL) == 0) 572 ; 573 574 /* always return EINTR rather than ERESTART... */ 575 return (EINTR); 576 } 577 578 int 579 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 580 struct sigaltstack *oss) 581 { 582 struct proc *p = l->l_proc; 583 int error = 0; 584 585 mutex_enter(p->p_lock); 586 587 if (oss) 588 *oss = l->l_sigstk; 589 590 if (nss) { 591 if (nss->ss_flags & ~SS_ALLBITS) 592 error = EINVAL; 593 else if (nss->ss_flags & SS_DISABLE) { 594 if (l->l_sigstk.ss_flags & SS_ONSTACK) 595 error = EINVAL; 596 } else if (nss->ss_size < MINSIGSTKSZ) 597 error = ENOMEM; 598 599 if (!error) 600 l->l_sigstk = *nss; 601 } 602 603 mutex_exit(p->p_lock); 604 605 return (error); 606 } 607 608 int 609 __sigtimedwait1(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval, 610 copyout_t put_info, copyin_t fetch_timeout, copyout_t put_timeout) 611 { 612 /* { 613 syscallarg(const sigset_t *) set; 614 syscallarg(siginfo_t *) info; 615 syscallarg(struct timespec *) timeout; 616 } */ 617 struct proc *p = l->l_proc; 618 int error, signum; 619 int timo = 0; 620 struct timespec ts, tsstart, tsnow; 621 ksiginfo_t *ksi; 622 623 memset(&tsstart, 0, sizeof tsstart); /* XXX gcc */ 624 625 /* 626 * Calculate timeout, if it was specified. 627 */ 628 if (SCARG(uap, timeout)) { 629 uint64_t ms; 630 631 if ((error = (*fetch_timeout)(SCARG(uap, timeout), &ts, sizeof(ts)))) 632 return (error); 633 634 ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000); 635 timo = mstohz(ms); 636 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0) 637 timo = 1; 638 if (timo <= 0) 639 return (EAGAIN); 640 641 /* 642 * Remember current uptime, it would be used in 643 * ECANCELED/ERESTART case. 644 */ 645 getnanouptime(&tsstart); 646 } 647 648 error = copyin(SCARG(uap, set), &l->l_sigwaitset, 649 sizeof(l->l_sigwaitset)); 650 if (error != 0) 651 return (error); 652 653 /* 654 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 655 * SA_CANTMASK signals in waitset, we do this only for the below 656 * siglist check. 657 */ 658 sigminusset(&sigcantmask, &l->l_sigwaitset); 659 660 /* 661 * Allocate a ksi up front. We can't sleep with the mutex held. 662 */ 663 ksi = ksiginfo_alloc(p, NULL, PR_WAITOK); 664 if (ksi == NULL) 665 return (ENOMEM); 666 667 mutex_enter(p->p_lock); 668 669 if ((signum = sigget(&p->p_sigpend, ksi, 0, &l->l_sigwaitset)) == 0) 670 signum = sigget(&l->l_sigpend, ksi, 0, &l->l_sigwaitset); 671 672 if (signum != 0) { 673 /* 674 * We found a pending signal - copy it out to the user. 675 */ 676 mutex_exit(p->p_lock); 677 goto out; 678 } 679 680 /* 681 * Set up the sigwait list. 682 */ 683 l->l_sigwaited = ksi; 684 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 685 686 /* 687 * Wait for signal to arrive. We can either be woken up or time out. 688 */ 689 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 690 691 /* 692 * Need to find out if we woke as a result of lwp_wakeup() or a 693 * signal outside our wait set. 694 */ 695 if (l->l_sigwaited != NULL) { 696 if (error == EINTR) { 697 /* wakeup via _lwp_wakeup() */ 698 error = ECANCELED; 699 } else if (!error) { 700 /* spurious wakeup - arrange for syscall restart */ 701 error = ERESTART; 702 } 703 l->l_sigwaited = NULL; 704 LIST_REMOVE(l, l_sigwaiter); 705 } 706 707 mutex_exit(p->p_lock); 708 709 /* 710 * If the sleep was interrupted (either by signal or wakeup), update 711 * the timeout and copyout new value back. It would be used when 712 * the syscall would be restarted or called again. 713 */ 714 if (timo && (error == ERESTART || error == ECANCELED)) { 715 getnanouptime(&tsnow); 716 717 /* compute how much time has passed since start */ 718 timespecsub(&tsnow, &tsstart, &tsnow); 719 /* substract passed time from timeout */ 720 timespecsub(&ts, &tsnow, &ts); 721 722 if (ts.tv_sec < 0) 723 error = EAGAIN; 724 else { 725 /* copy updated timeout to userland */ 726 error = (*put_timeout)(&ts, SCARG(uap, timeout), 727 sizeof(ts)); 728 } 729 } 730 731 /* 732 * If a signal from the wait set arrived, copy it to userland. 733 * Copy only the used part of siginfo, the padding part is 734 * left unchanged (userland is not supposed to touch it anyway). 735 */ 736 out: 737 if (error == 0) 738 error = (*put_info)(&ksi->ksi_info, SCARG(uap, info), 739 sizeof(ksi->ksi_info)); 740 741 ksiginfo_free(ksi); 742 743 return error; 744 } 745
Indexes created Mon Sep 29 18:09:42 GMT 2025