1 /* $NetBSD: sys_sig.c,v 1.38 2012/07/18 20:30:07 christos 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 1.38 2012/07/18 20:30:07 christos Exp $"); 70 71 #include <sys/param.h> 72 #include <sys/kernel.h> 73 #include <sys/signalvar.h> 74 #include <sys/proc.h> 75 #include <sys/pool.h> 76 #include <sys/syscallargs.h> 77 #include <sys/kauth.h> 78 #include <sys/wait.h> 79 #include <sys/kmem.h> 80 #include <sys/module.h> 81 82 int 83 sys___sigaction_sigtramp(struct lwp *l, 84 const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 85 { 86 /* { 87 syscallarg(int) signum; 88 syscallarg(const struct sigaction *) nsa; 89 syscallarg(struct sigaction *) osa; 90 syscallarg(void *) tramp; 91 syscallarg(int) vers; 92 } */ 93 struct sigaction nsa, osa; 94 int error; 95 96 if (SCARG(uap, nsa)) { 97 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 98 if (error) 99 return (error); 100 } 101 error = sigaction1(l, SCARG(uap, signum), 102 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 103 SCARG(uap, tramp), SCARG(uap, vers)); 104 if (error) 105 return (error); 106 if (SCARG(uap, osa)) { 107 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 108 if (error) 109 return (error); 110 } 111 return 0; 112 } 113 114 /* 115 * Manipulate signal mask. Note that we receive new mask, not pointer, and 116 * return old mask as return value; the library stub does the rest. 117 */ 118 int 119 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, 120 register_t *retval) 121 { 122 /* { 123 syscallarg(int) how; 124 syscallarg(const sigset_t *) set; 125 syscallarg(sigset_t *) oset; 126 } */ 127 struct proc *p = l->l_proc; 128 sigset_t nss, oss; 129 int error; 130 131 if (SCARG(uap, set)) { 132 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 133 if (error) 134 return error; 135 } 136 mutex_enter(p->p_lock); 137 error = sigprocmask1(l, SCARG(uap, how), 138 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 139 mutex_exit(p->p_lock); 140 if (error) 141 return error; 142 if (SCARG(uap, oset)) { 143 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 144 if (error) 145 return error; 146 } 147 return 0; 148 } 149 150 int 151 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, 152 register_t *retval) 153 { 154 /* { 155 syscallarg(sigset_t *) set; 156 } */ 157 sigset_t ss; 158 159 sigpending1(l, &ss); 160 return copyout(&ss, SCARG(uap, set), sizeof(ss)); 161 } 162 163 /* 164 * Suspend process until signal, providing mask to be set in the meantime. 165 * Note nonstandard calling convention: libc stub passes mask, not pointer, 166 * to save a copyin. 167 */ 168 int 169 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, 170 register_t *retval) 171 { 172 /* { 173 syscallarg(const sigset_t *) set; 174 } */ 175 sigset_t ss; 176 int error; 177 178 if (SCARG(uap, set)) { 179 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 180 if (error) 181 return error; 182 } 183 return sigsuspend1(l, SCARG(uap, set) ? &ss : 0); 184 } 185 186 int 187 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, 188 register_t *retval) 189 { 190 /* { 191 syscallarg(const struct sigaltstack *) nss; 192 syscallarg(struct sigaltstack *) oss; 193 } */ 194 struct sigaltstack nss, oss; 195 int error; 196 197 if (SCARG(uap, nss)) { 198 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 199 if (error) 200 return error; 201 } 202 error = sigaltstack1(l, 203 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 204 if (error) 205 return error; 206 if (SCARG(uap, oss)) { 207 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 208 if (error) 209 return error; 210 } 211 return 0; 212 } 213 214 215 static int 216 kill1(struct lwp *l, pid_t pid, ksiginfo_t *ksi, register_t *retval) 217 { 218 int error; 219 struct proc *p; 220 221 if ((u_int)ksi->ksi_signo >= NSIG) 222 return EINVAL; 223 224 if (pid != l->l_proc->p_pid) { 225 if (ksi->ksi_pid != l->l_proc->p_pid) 226 return EPERM; 227 228 if (ksi->ksi_uid != kauth_cred_geteuid(l->l_cred)) 229 return EPERM; 230 231 switch (ksi->ksi_code) { 232 case SI_USER: 233 case SI_QUEUE: 234 break; 235 default: 236 return EPERM; 237 } 238 } 239 240 if (pid > 0) { 241 /* kill single process */ 242 mutex_enter(proc_lock); 243 p = proc_find_raw(pid); 244 if (p == NULL || (p->p_stat != SACTIVE && p->p_stat != SSTOP)) { 245 mutex_exit(proc_lock); 246 /* IEEE Std 1003.1-2001: return success for zombies */ 247 return p ? 0 : ESRCH; 248 } 249 mutex_enter(p->p_lock); 250 error = kauth_authorize_process(l->l_cred, 251 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(ksi->ksi_signo), 252 NULL, NULL); 253 if (!error && ksi->ksi_signo) { 254 kpsignal2(p, ksi); 255 } 256 mutex_exit(p->p_lock); 257 mutex_exit(proc_lock); 258 return error; 259 } 260 261 switch (pid) { 262 case -1: /* broadcast signal */ 263 return killpg1(l, ksi, 0, 1); 264 case 0: /* signal own process group */ 265 return killpg1(l, ksi, 0, 0); 266 default: /* negative explicit process group */ 267 return killpg1(l, ksi, -pid, 0); 268 } 269 /* NOTREACHED */ 270 } 271 272 int 273 sys_sigqueueinfo(struct lwp *l, const struct sys_sigqueueinfo_args *uap, 274 register_t *retval) 275 { 276 /* { 277 syscallarg(pid_t int) pid; 278 syscallarg(const siginfo_t *) info; 279 } */ 280 ksiginfo_t ksi; 281 int error; 282 283 KSI_INIT(&ksi); 284 285 if ((error = copyin(&SCARG(uap, info)->_info, &ksi.ksi_info, 286 sizeof(ksi.ksi_info))) != 0) 287 return error; 288 289 return kill1(l, SCARG(uap, pid), &ksi, retval); 290 } 291 292 int 293 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 294 { 295 /* { 296 syscallarg(pid_t) pid; 297 syscallarg(int) signum; 298 } */ 299 ksiginfo_t ksi; 300 301 KSI_INIT(&ksi); 302 303 ksi.ksi_signo = SCARG(uap, signum); 304 ksi.ksi_code = SI_USER; 305 ksi.ksi_pid = l->l_proc->p_pid; 306 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 307 308 return kill1(l, SCARG(uap, pid), &ksi, retval); 309 } 310 311 int 312 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, 313 register_t *retval) 314 { 315 /* { 316 syscallarg(struct __ucontext *) ucp; 317 } */ 318 struct proc *p = l->l_proc; 319 ucontext_t uc; 320 321 memset(&uc, 0, sizeof(uc)); 322 323 mutex_enter(p->p_lock); 324 getucontext(l, &uc); 325 mutex_exit(p->p_lock); 326 327 return copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp))); 328 } 329 330 int 331 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, 332 register_t *retval) 333 { 334 /* { 335 syscallarg(const ucontext_t *) ucp; 336 } */ 337 struct proc *p = l->l_proc; 338 ucontext_t uc; 339 int error; 340 341 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 342 if (error) 343 return error; 344 if ((uc.uc_flags & _UC_CPU) == 0) 345 return EINVAL; 346 mutex_enter(p->p_lock); 347 error = setucontext(l, &uc); 348 mutex_exit(p->p_lock); 349 if (error) 350 return error; 351 352 return EJUSTRETURN; 353 } 354 355 /* 356 * sigtimedwait(2) system call, used also for implementation 357 * of sigwaitinfo() and sigwait(). 358 * 359 * This only handles single LWP in signal wait. libpthread provides 360 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 361 */ 362 int 363 sys_____sigtimedwait50(struct lwp *l, 364 const struct sys_____sigtimedwait50_args *uap, register_t *retval) 365 { 366 367 return sigtimedwait1(l, uap, retval, copyin, copyout, copyin, copyout); 368 } 369 370 int 371 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 372 struct sigaction *osa, const void *tramp, int vers) 373 { 374 struct proc *p; 375 struct sigacts *ps; 376 sigset_t tset; 377 int prop, error; 378 ksiginfoq_t kq; 379 static bool v0v1valid; 380 381 if (signum <= 0 || signum >= NSIG) 382 return EINVAL; 383 384 p = l->l_proc; 385 error = 0; 386 ksiginfo_queue_init(&kq); 387 388 /* 389 * Trampoline ABI version 0 is reserved for the legacy kernel 390 * provided on-stack trampoline. Conversely, if we are using a 391 * non-0 ABI version, we must have a trampoline. Only validate the 392 * vers if a new sigaction was supplied. Emulations use legacy 393 * kernel trampolines with version 0, alternatively check for that 394 * too. 395 * 396 * If version < 2, we try to autoload the compat module. Note 397 * that we interlock with the unload check in compat_modcmd() 398 * using kernconfig_lock. If the autoload fails, we don't try it 399 * again for this process. 400 */ 401 if (nsa != NULL) { 402 if (__predict_false(vers < 2) && 403 (p->p_lflag & PL_SIGCOMPAT) == 0) { 404 kernconfig_lock(); 405 if (sendsig_sigcontext_vec == NULL) { 406 (void)module_autoload("compat", 407 MODULE_CLASS_ANY); 408 } 409 if (sendsig_sigcontext_vec != NULL) { 410 /* 411 * We need to remember if the 412 * sigcontext method may be useable, 413 * because libc may use it even 414 * if siginfo is available. 415 */ 416 v0v1valid = true; 417 } 418 mutex_enter(proc_lock); 419 /* 420 * Prevent unload of compat module while 421 * this process remains. 422 */ 423 p->p_lflag |= PL_SIGCOMPAT; 424 mutex_exit(proc_lock); 425 kernconfig_unlock(); 426 } 427 428 switch (vers) { 429 case 0: 430 /* sigcontext, kernel supplied trampoline. */ 431 if (tramp != NULL || !v0v1valid) { 432 return EINVAL; 433 } 434 break; 435 case 1: 436 /* sigcontext, user supplied trampoline. */ 437 if (tramp == NULL || !v0v1valid) { 438 return EINVAL; 439 } 440 break; 441 case 2: 442 case 3: 443 /* siginfo, user supplied trampoline. */ 444 if (tramp == NULL) { 445 return EINVAL; 446 } 447 break; 448 default: 449 return EINVAL; 450 } 451 } 452 453 mutex_enter(p->p_lock); 454 455 ps = p->p_sigacts; 456 if (osa) 457 *osa = SIGACTION_PS(ps, signum); 458 if (!nsa) 459 goto out; 460 461 prop = sigprop[signum]; 462 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 463 error = EINVAL; 464 goto out; 465 } 466 467 SIGACTION_PS(ps, signum) = *nsa; 468 ps->sa_sigdesc[signum].sd_tramp = tramp; 469 ps->sa_sigdesc[signum].sd_vers = vers; 470 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 471 472 if ((prop & SA_NORESET) != 0) 473 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 474 475 if (signum == SIGCHLD) { 476 if (nsa->sa_flags & SA_NOCLDSTOP) 477 p->p_sflag |= PS_NOCLDSTOP; 478 else 479 p->p_sflag &= ~PS_NOCLDSTOP; 480 if (nsa->sa_flags & SA_NOCLDWAIT) { 481 /* 482 * Paranoia: since SA_NOCLDWAIT is implemented by 483 * reparenting the dying child to PID 1 (and trust 484 * it to reap the zombie), PID 1 itself is forbidden 485 * to set SA_NOCLDWAIT. 486 */ 487 if (p->p_pid == 1) 488 p->p_flag &= ~PK_NOCLDWAIT; 489 else 490 p->p_flag |= PK_NOCLDWAIT; 491 } else 492 p->p_flag &= ~PK_NOCLDWAIT; 493 494 if (nsa->sa_handler == SIG_IGN) { 495 /* 496 * Paranoia: same as above. 497 */ 498 if (p->p_pid == 1) 499 p->p_flag &= ~PK_CLDSIGIGN; 500 else 501 p->p_flag |= PK_CLDSIGIGN; 502 } else 503 p->p_flag &= ~PK_CLDSIGIGN; 504 } 505 506 if ((nsa->sa_flags & SA_NODEFER) == 0) 507 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 508 else 509 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 510 511 /* 512 * Set bit in p_sigctx.ps_sigignore for signals that are set to 513 * SIG_IGN, and for signals set to SIG_DFL where the default is to 514 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 515 * we have to restart the process. 516 */ 517 if (nsa->sa_handler == SIG_IGN || 518 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 519 /* Never to be seen again. */ 520 sigemptyset(&tset); 521 sigaddset(&tset, signum); 522 sigclearall(p, &tset, &kq); 523 if (signum != SIGCONT) { 524 /* Easier in psignal */ 525 sigaddset(&p->p_sigctx.ps_sigignore, signum); 526 } 527 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 528 } else { 529 sigdelset(&p->p_sigctx.ps_sigignore, signum); 530 if (nsa->sa_handler == SIG_DFL) 531 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 532 else 533 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 534 } 535 536 /* 537 * Previously held signals may now have become visible. Ensure that 538 * we check for them before returning to userspace. 539 */ 540 if (sigispending(l, 0)) { 541 lwp_lock(l); 542 l->l_flag |= LW_PENDSIG; 543 lwp_unlock(l); 544 } 545 out: 546 mutex_exit(p->p_lock); 547 ksiginfo_queue_drain(&kq); 548 549 return error; 550 } 551 552 int 553 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 554 { 555 sigset_t *mask = &l->l_sigmask; 556 bool more; 557 558 KASSERT(mutex_owned(l->l_proc->p_lock)); 559 560 if (oss) { 561 *oss = *mask; 562 } 563 564 if (nss == NULL) { 565 return 0; 566 } 567 568 switch (how) { 569 case SIG_BLOCK: 570 sigplusset(nss, mask); 571 more = false; 572 break; 573 case SIG_UNBLOCK: 574 sigminusset(nss, mask); 575 more = true; 576 break; 577 case SIG_SETMASK: 578 *mask = *nss; 579 more = true; 580 break; 581 default: 582 return EINVAL; 583 } 584 sigminusset(&sigcantmask, mask); 585 if (more && sigispending(l, 0)) { 586 /* 587 * Check for pending signals on return to user. 588 */ 589 lwp_lock(l); 590 l->l_flag |= LW_PENDSIG; 591 lwp_unlock(l); 592 } 593 return 0; 594 } 595 596 void 597 sigpending1(struct lwp *l, sigset_t *ss) 598 { 599 struct proc *p = l->l_proc; 600 601 mutex_enter(p->p_lock); 602 *ss = l->l_sigpend.sp_set; 603 sigplusset(&p->p_sigpend.sp_set, ss); 604 mutex_exit(p->p_lock); 605 } 606 607 void 608 sigsuspendsetup(struct lwp *l, const sigset_t *ss) 609 { 610 struct proc *p = l->l_proc; 611 612 /* 613 * When returning from sigsuspend/pselect/pollts, we want 614 * the old mask to be restored after the 615 * signal handler has finished. Thus, we 616 * save it here and mark the sigctx structure 617 * to indicate this. 618 */ 619 mutex_enter(p->p_lock); 620 l->l_sigrestore = 1; 621 l->l_sigoldmask = l->l_sigmask; 622 l->l_sigmask = *ss; 623 sigminusset(&sigcantmask, &l->l_sigmask); 624 625 /* Check for pending signals when sleeping. */ 626 if (sigispending(l, 0)) { 627 lwp_lock(l); 628 l->l_flag |= LW_PENDSIG; 629 lwp_unlock(l); 630 } 631 mutex_exit(p->p_lock); 632 } 633 634 void 635 sigsuspendteardown(struct lwp *l) 636 { 637 struct proc *p = l->l_proc; 638 639 mutex_enter(p->p_lock); 640 /* Check for pending signals when sleeping. */ 641 if (l->l_sigrestore) { 642 if (sigispending(l, 0)) { 643 lwp_lock(l); 644 l->l_flag |= LW_PENDSIG; 645 lwp_unlock(l); 646 } else { 647 l->l_sigrestore = 0; 648 l->l_sigmask = l->l_sigoldmask; 649 } 650 } 651 mutex_exit(p->p_lock); 652 } 653 654 int 655 sigsuspend1(struct lwp *l, const sigset_t *ss) 656 { 657 658 if (ss) 659 sigsuspendsetup(l, ss); 660 661 while (kpause("pause", true, 0, NULL) == 0) 662 ; 663 664 /* always return EINTR rather than ERESTART... */ 665 return EINTR; 666 } 667 668 int 669 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 670 struct sigaltstack *oss) 671 { 672 struct proc *p = l->l_proc; 673 int error = 0; 674 675 mutex_enter(p->p_lock); 676 677 if (oss) 678 *oss = l->l_sigstk; 679 680 if (nss) { 681 if (nss->ss_flags & ~SS_ALLBITS) 682 error = EINVAL; 683 else if (nss->ss_flags & SS_DISABLE) { 684 if (l->l_sigstk.ss_flags & SS_ONSTACK) 685 error = EINVAL; 686 } else if (nss->ss_size < MINSIGSTKSZ) 687 error = ENOMEM; 688 689 if (!error) 690 l->l_sigstk = *nss; 691 } 692 693 mutex_exit(p->p_lock); 694 695 return error; 696 } 697 698 int 699 sigtimedwait1(struct lwp *l, const struct sys_____sigtimedwait50_args *uap, 700 register_t *retval, copyin_t fetchss, copyout_t storeinf, copyin_t fetchts, 701 copyout_t storets) 702 { 703 /* { 704 syscallarg(const sigset_t *) set; 705 syscallarg(siginfo_t *) info; 706 syscallarg(struct timespec *) timeout; 707 } */ 708 struct proc *p = l->l_proc; 709 int error, signum, timo; 710 struct timespec ts, tsstart, tsnow; 711 ksiginfo_t ksi; 712 713 /* 714 * Calculate timeout, if it was specified. 715 */ 716 if (SCARG(uap, timeout)) { 717 error = (*fetchts)(SCARG(uap, timeout), &ts, sizeof(ts)); 718 if (error) 719 return error; 720 721 if ((error = itimespecfix(&ts)) != 0) 722 return error; 723 724 timo = tstohz(&ts); 725 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec != 0) 726 timo++; 727 728 /* 729 * Remember current uptime, it would be used in 730 * ECANCELED/ERESTART case. 731 */ 732 getnanouptime(&tsstart); 733 } else { 734 memset(&tsstart, 0, sizeof(tsstart)); /* XXXgcc */ 735 timo = 0; 736 } 737 738 error = (*fetchss)(SCARG(uap, set), &l->l_sigwaitset, 739 sizeof(l->l_sigwaitset)); 740 if (error) 741 return error; 742 743 /* 744 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 745 * SA_CANTMASK signals in waitset, we do this only for the below 746 * siglist check. 747 */ 748 sigminusset(&sigcantmask, &l->l_sigwaitset); 749 750 mutex_enter(p->p_lock); 751 752 /* Check for pending signals in the process, if no - then in LWP. */ 753 if ((signum = sigget(&p->p_sigpend, &ksi, 0, &l->l_sigwaitset)) == 0) 754 signum = sigget(&l->l_sigpend, &ksi, 0, &l->l_sigwaitset); 755 756 if (signum != 0) { 757 /* If found a pending signal, just copy it out to the user. */ 758 mutex_exit(p->p_lock); 759 goto out; 760 } 761 762 /* 763 * Set up the sigwait list and wait for signal to arrive. 764 * We can either be woken up or time out. 765 */ 766 l->l_sigwaited = &ksi; 767 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 768 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 769 770 /* 771 * Need to find out if we woke as a result of _lwp_wakeup() or a 772 * signal outside our wait set. 773 */ 774 if (l->l_sigwaited != NULL) { 775 if (error == EINTR) { 776 /* Wakeup via _lwp_wakeup(). */ 777 error = ECANCELED; 778 } else if (!error) { 779 /* Spurious wakeup - arrange for syscall restart. */ 780 error = ERESTART; 781 } 782 l->l_sigwaited = NULL; 783 LIST_REMOVE(l, l_sigwaiter); 784 } 785 mutex_exit(p->p_lock); 786 787 /* 788 * If the sleep was interrupted (either by signal or wakeup), update 789 * the timeout and copyout new value back. It would be used when 790 * the syscall would be restarted or called again. 791 */ 792 if (timo && (error == ERESTART || error == ECANCELED)) { 793 getnanouptime(&tsnow); 794 795 /* Compute how much time has passed since start. */ 796 timespecsub(&tsnow, &tsstart, &tsnow); 797 798 /* Substract passed time from timeout. */ 799 timespecsub(&ts, &tsnow, &ts); 800 801 if (ts.tv_sec < 0) 802 error = EAGAIN; 803 else { 804 /* Copy updated timeout to userland. */ 805 error = (*storets)(&ts, SCARG(uap, timeout), 806 sizeof(ts)); 807 } 808 } 809 out: 810 /* 811 * If a signal from the wait set arrived, copy it to userland. 812 * Copy only the used part of siginfo, the padding part is 813 * left unchanged (userland is not supposed to touch it anyway). 814 */ 815 if (error == 0 && SCARG(uap, info)) { 816 error = (*storeinf)(&ksi.ksi_info, SCARG(uap, info), 817 sizeof(ksi.ksi_info)); 818 } 819 if (error == 0) 820 *retval = ksi.ksi_info._signo; 821 return error; 822 } 823