1 /* $NetBSD: sys_sig.c,v 1.20 2008/11/25 16:42:44 ad 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 1.20 2008/11/25 16:42:44 ad 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/sa.h> 77 #include <sys/savar.h> 78 #include <sys/syscallargs.h> 79 #include <sys/kauth.h> 80 #include <sys/wait.h> 81 #include <sys/kmem.h> 82 #include <sys/module.h> 83 84 /* ARGSUSED */ 85 int 86 sys___sigaction_sigtramp(struct lwp *l, const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 87 { 88 /* { 89 syscallarg(int) signum; 90 syscallarg(const struct sigaction *) nsa; 91 syscallarg(struct sigaction *) osa; 92 syscallarg(void *) tramp; 93 syscallarg(int) vers; 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 SCARG(uap, tramp), SCARG(uap, vers)); 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 } 115 116 /* 117 * Manipulate signal mask. Note that we receive new mask, not pointer, and 118 * return old mask as return value; the library stub does the rest. 119 */ 120 int 121 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, register_t *retval) 122 { 123 /* { 124 syscallarg(int) how; 125 syscallarg(const sigset_t *) set; 126 syscallarg(sigset_t *) oset; 127 } */ 128 struct proc *p = l->l_proc; 129 sigset_t nss, oss; 130 int error; 131 132 if (SCARG(uap, set)) { 133 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 134 if (error) 135 return (error); 136 } 137 mutex_enter(p->p_lock); 138 error = sigprocmask1(l, SCARG(uap, how), 139 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 140 mutex_exit(p->p_lock); 141 if (error) 142 return (error); 143 if (SCARG(uap, oset)) { 144 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 145 if (error) 146 return (error); 147 } 148 return (0); 149 } 150 151 /* ARGSUSED */ 152 int 153 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, register_t *retval) 154 { 155 /* { 156 syscallarg(sigset_t *) set; 157 } */ 158 sigset_t ss; 159 160 sigpending1(l, &ss); 161 return (copyout(&ss, SCARG(uap, set), sizeof(ss))); 162 } 163 164 /* 165 * Suspend process until signal, providing mask to be set in the meantime. 166 * Note nonstandard calling convention: libc stub passes mask, not pointer, 167 * to save a copyin. 168 */ 169 /* ARGSUSED */ 170 int 171 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, register_t *retval) 172 { 173 /* { 174 syscallarg(const sigset_t *) set; 175 } */ 176 sigset_t ss; 177 int error; 178 179 if (SCARG(uap, set)) { 180 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 181 if (error) 182 return (error); 183 } 184 185 return (sigsuspend1(l, SCARG(uap, set) ? &ss : 0)); 186 } 187 188 /* ARGSUSED */ 189 int 190 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, register_t *retval) 191 { 192 /* { 193 syscallarg(const struct sigaltstack *) nss; 194 syscallarg(struct sigaltstack *) oss; 195 } */ 196 struct sigaltstack nss, oss; 197 int error; 198 199 if (SCARG(uap, nss)) { 200 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 201 if (error) 202 return (error); 203 } 204 error = sigaltstack1(l, 205 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 206 if (error) 207 return (error); 208 if (SCARG(uap, oss)) { 209 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 210 if (error) 211 return (error); 212 } 213 return (0); 214 } 215 216 /* ARGSUSED */ 217 int 218 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 219 { 220 /* { 221 syscallarg(int) pid; 222 syscallarg(int) signum; 223 } */ 224 struct proc *p; 225 ksiginfo_t ksi; 226 int signum = SCARG(uap, signum); 227 int error; 228 229 if ((u_int)signum >= NSIG) 230 return (EINVAL); 231 KSI_INIT(&ksi); 232 ksi.ksi_signo = signum; 233 ksi.ksi_code = SI_USER; 234 ksi.ksi_pid = l->l_proc->p_pid; 235 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 236 if (SCARG(uap, pid) > 0) { 237 /* kill single process */ 238 mutex_enter(proc_lock); 239 if ((p = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) { 240 mutex_exit(proc_lock); 241 return (ESRCH); 242 } 243 mutex_enter(p->p_lock); 244 error = kauth_authorize_process(l->l_cred, 245 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signum), 246 NULL, NULL); 247 if (!error && signum) { 248 kpsignal2(p, &ksi); 249 } 250 mutex_exit(p->p_lock); 251 mutex_exit(proc_lock); 252 return (error); 253 } 254 switch (SCARG(uap, pid)) { 255 case -1: /* broadcast signal */ 256 return (killpg1(l, &ksi, 0, 1)); 257 case 0: /* signal own process group */ 258 return (killpg1(l, &ksi, 0, 0)); 259 default: /* negative explicit process group */ 260 return (killpg1(l, &ksi, -SCARG(uap, pid), 0)); 261 } 262 /* NOTREACHED */ 263 } 264 265 /* ARGSUSED */ 266 int 267 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, register_t *retval) 268 { 269 /* { 270 syscallarg(struct __ucontext *) ucp; 271 } */ 272 struct proc *p = l->l_proc; 273 ucontext_t uc; 274 275 mutex_enter(p->p_lock); 276 getucontext(l, &uc); 277 mutex_exit(p->p_lock); 278 279 return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp)))); 280 } 281 282 /* ARGSUSED */ 283 int 284 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, register_t *retval) 285 { 286 /* { 287 syscallarg(const ucontext_t *) ucp; 288 } */ 289 struct proc *p = l->l_proc; 290 ucontext_t uc; 291 int error; 292 293 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 294 if (error) 295 return (error); 296 if (!(uc.uc_flags & _UC_CPU)) 297 return (EINVAL); 298 mutex_enter(p->p_lock); 299 error = setucontext(l, &uc); 300 mutex_exit(p->p_lock); 301 if (error) 302 return (error); 303 304 return (EJUSTRETURN); 305 } 306 307 /* 308 * sigtimedwait(2) system call, used also for implementation 309 * of sigwaitinfo() and sigwait(). 310 * 311 * This only handles single LWP in signal wait. libpthread provides 312 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 313 */ 314 int 315 sys___sigtimedwait(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval) 316 { 317 318 return __sigtimedwait1(l, uap, retval, copyout, copyin, copyout); 319 } 320 321 int 322 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 323 struct sigaction *osa, const void *tramp, int vers) 324 { 325 struct proc *p; 326 struct sigacts *ps; 327 sigset_t tset; 328 int prop, error; 329 ksiginfoq_t kq; 330 static bool v0v1valid; 331 332 if (signum <= 0 || signum >= NSIG) 333 return (EINVAL); 334 335 p = l->l_proc; 336 error = 0; 337 ksiginfo_queue_init(&kq); 338 339 /* 340 * Trampoline ABI version 0 is reserved for the legacy kernel 341 * provided on-stack trampoline. Conversely, if we are using a 342 * non-0 ABI version, we must have a trampoline. Only validate the 343 * vers if a new sigaction was supplied. Emulations use legacy 344 * kernel trampolines with version 0, alternatively check for that 345 * too. 346 * 347 * If version < 2, we try to autoload the compat module. Note 348 * that we interlock with the unload check in compat_modcmd() 349 * using module_lock. If the autoload fails, we don't try it 350 * again for this process. 351 */ 352 if (nsa != NULL) { 353 if (__predict_false(vers < 2) && 354 (p->p_lflag & PL_SIGCOMPAT) == 0) { 355 mutex_enter(&module_lock); 356 if (sendsig_sigcontext_vec == NULL) { 357 (void)module_autoload("compat", 358 MODULE_CLASS_ANY); 359 } 360 if (sendsig_sigcontext_vec != NULL) { 361 /* 362 * We need to remember if the 363 * sigcontext method may be useable, 364 * because libc may use it even 365 * if siginfo is available. 366 */ 367 v0v1valid = true; 368 } 369 mutex_enter(proc_lock); 370 /* 371 * Prevent unload of compat module while 372 * this process remains. 373 */ 374 p->p_lflag |= PL_SIGCOMPAT; 375 mutex_exit(proc_lock); 376 mutex_exit(&module_lock); 377 } 378 379 switch (vers) { 380 case 0: 381 /* sigcontext, kernel supplied trampoline. */ 382 if (tramp != NULL || !v0v1valid) { 383 return EINVAL; 384 } 385 break; 386 case 1: 387 /* sigcontext, user supplied trampoline. */ 388 if (tramp == NULL || !v0v1valid) { 389 return EINVAL; 390 } 391 break; 392 case 2: 393 case 3: 394 /* siginfo, user supplied trampoline. */ 395 if (tramp == NULL) { 396 return EINVAL; 397 } 398 break; 399 default: 400 return EINVAL; 401 } 402 } 403 404 mutex_enter(p->p_lock); 405 406 ps = p->p_sigacts; 407 if (osa) 408 *osa = SIGACTION_PS(ps, signum); 409 if (!nsa) 410 goto out; 411 412 prop = sigprop[signum]; 413 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 414 error = EINVAL; 415 goto out; 416 } 417 418 SIGACTION_PS(ps, signum) = *nsa; 419 ps->sa_sigdesc[signum].sd_tramp = tramp; 420 ps->sa_sigdesc[signum].sd_vers = vers; 421 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 422 423 if ((prop & SA_NORESET) != 0) 424 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 425 426 if (signum == SIGCHLD) { 427 if (nsa->sa_flags & SA_NOCLDSTOP) 428 p->p_sflag |= PS_NOCLDSTOP; 429 else 430 p->p_sflag &= ~PS_NOCLDSTOP; 431 if (nsa->sa_flags & SA_NOCLDWAIT) { 432 /* 433 * Paranoia: since SA_NOCLDWAIT is implemented by 434 * reparenting the dying child to PID 1 (and trust 435 * it to reap the zombie), PID 1 itself is forbidden 436 * to set SA_NOCLDWAIT. 437 */ 438 if (p->p_pid == 1) 439 p->p_flag &= ~PK_NOCLDWAIT; 440 else 441 p->p_flag |= PK_NOCLDWAIT; 442 } else 443 p->p_flag &= ~PK_NOCLDWAIT; 444 445 if (nsa->sa_handler == SIG_IGN) { 446 /* 447 * Paranoia: same as above. 448 */ 449 if (p->p_pid == 1) 450 p->p_flag &= ~PK_CLDSIGIGN; 451 else 452 p->p_flag |= PK_CLDSIGIGN; 453 } else 454 p->p_flag &= ~PK_CLDSIGIGN; 455 } 456 457 if ((nsa->sa_flags & SA_NODEFER) == 0) 458 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 459 else 460 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 461 462 /* 463 * Set bit in p_sigctx.ps_sigignore for signals that are set to 464 * SIG_IGN, and for signals set to SIG_DFL where the default is to 465 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 466 * we have to restart the process. 467 */ 468 if (nsa->sa_handler == SIG_IGN || 469 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 470 /* Never to be seen again. */ 471 sigemptyset(&tset); 472 sigaddset(&tset, signum); 473 sigclearall(p, &tset, &kq); 474 if (signum != SIGCONT) { 475 /* Easier in psignal */ 476 sigaddset(&p->p_sigctx.ps_sigignore, signum); 477 } 478 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 479 } else { 480 sigdelset(&p->p_sigctx.ps_sigignore, signum); 481 if (nsa->sa_handler == SIG_DFL) 482 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 483 else 484 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 485 } 486 487 /* 488 * Previously held signals may now have become visible. Ensure that 489 * we check for them before returning to userspace. 490 */ 491 if (sigispending(l, 0)) { 492 lwp_lock(l); 493 l->l_flag |= LW_PENDSIG; 494 lwp_unlock(l); 495 } 496 out: 497 mutex_exit(p->p_lock); 498 ksiginfo_queue_drain(&kq); 499 500 return (error); 501 } 502 503 int 504 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 505 { 506 int more; 507 struct proc *p = l->l_proc; 508 sigset_t *mask; 509 mask = (p->p_sa != NULL) ? &p->p_sa->sa_sigmask : &l->l_sigmask; 510 511 KASSERT(mutex_owned(p->p_lock)); 512 513 if (oss) 514 *oss = *mask; 515 if (nss) { 516 switch (how) { 517 case SIG_BLOCK: 518 sigplusset(nss, mask); 519 more = 0; 520 break; 521 case SIG_UNBLOCK: 522 sigminusset(nss, mask); 523 more = 1; 524 break; 525 case SIG_SETMASK: 526 *mask = *nss; 527 more = 1; 528 break; 529 default: 530 return (EINVAL); 531 } 532 sigminusset(&sigcantmask, mask); 533 if (more && sigispending(l, 0)) { 534 /* 535 * Check for pending signals on return to user. 536 */ 537 lwp_lock(l); 538 l->l_flag |= LW_PENDSIG; 539 lwp_unlock(l); 540 } 541 } 542 543 return (0); 544 } 545 546 void 547 sigpending1(struct lwp *l, sigset_t *ss) 548 { 549 struct proc *p = l->l_proc; 550 551 mutex_enter(p->p_lock); 552 *ss = l->l_sigpend.sp_set; 553 sigplusset(&p->p_sigpend.sp_set, ss); 554 mutex_exit(p->p_lock); 555 } 556 557 int 558 sigsuspend1(struct lwp *l, const sigset_t *ss) 559 { 560 struct proc *p; 561 562 p = l->l_proc; 563 564 if (ss) { 565 /* 566 * When returning from sigsuspend, we want 567 * the old mask to be restored after the 568 * signal handler has finished. Thus, we 569 * save it here and mark the sigctx structure 570 * to indicate this. 571 */ 572 mutex_enter(p->p_lock); 573 l->l_sigrestore = 1; 574 l->l_sigoldmask = l->l_sigmask; 575 l->l_sigmask = *ss; 576 sigminusset(&sigcantmask, &l->l_sigmask); 577 578 /* Check for pending signals when sleeping. */ 579 if (sigispending(l, 0)) { 580 lwp_lock(l); 581 l->l_flag |= LW_PENDSIG; 582 lwp_unlock(l); 583 } 584 mutex_exit(p->p_lock); 585 } 586 587 while (kpause("pause", true, 0, NULL) == 0) 588 ; 589 590 /* always return EINTR rather than ERESTART... */ 591 return (EINTR); 592 } 593 594 int 595 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 596 struct sigaltstack *oss) 597 { 598 struct proc *p = l->l_proc; 599 int error = 0; 600 601 mutex_enter(p->p_lock); 602 603 if (oss) 604 *oss = l->l_sigstk; 605 606 if (nss) { 607 if (nss->ss_flags & ~SS_ALLBITS) 608 error = EINVAL; 609 else if (nss->ss_flags & SS_DISABLE) { 610 if (l->l_sigstk.ss_flags & SS_ONSTACK) 611 error = EINVAL; 612 } else if (nss->ss_size < MINSIGSTKSZ) 613 error = ENOMEM; 614 615 if (!error) 616 l->l_sigstk = *nss; 617 } 618 619 mutex_exit(p->p_lock); 620 621 return (error); 622 } 623 624 int 625 __sigtimedwait1(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval, 626 copyout_t put_info, copyin_t fetch_timeout, copyout_t put_timeout) 627 { 628 /* { 629 syscallarg(const sigset_t *) set; 630 syscallarg(siginfo_t *) info; 631 syscallarg(struct timespec *) timeout; 632 } */ 633 struct proc *p = l->l_proc; 634 int error, signum; 635 int timo = 0; 636 struct timespec ts, tsstart, tsnow; 637 ksiginfo_t *ksi; 638 639 memset(&tsstart, 0, sizeof tsstart); /* XXX gcc */ 640 641 /* 642 * Calculate timeout, if it was specified. 643 */ 644 if (SCARG(uap, timeout)) { 645 uint64_t ms; 646 647 if ((error = (*fetch_timeout)(SCARG(uap, timeout), &ts, sizeof(ts)))) 648 return (error); 649 650 ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000); 651 timo = mstohz(ms); 652 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0) 653 timo = 1; 654 if (timo <= 0) 655 return (EAGAIN); 656 657 /* 658 * Remember current uptime, it would be used in 659 * ECANCELED/ERESTART case. 660 */ 661 getnanouptime(&tsstart); 662 } 663 664 error = copyin(SCARG(uap, set), &l->l_sigwaitset, 665 sizeof(l->l_sigwaitset)); 666 if (error != 0) 667 return (error); 668 669 /* 670 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 671 * SA_CANTMASK signals in waitset, we do this only for the below 672 * siglist check. 673 */ 674 sigminusset(&sigcantmask, &l->l_sigwaitset); 675 676 /* 677 * Allocate a ksi up front. We can't sleep with the mutex held. 678 */ 679 ksi = ksiginfo_alloc(p, NULL, PR_WAITOK); 680 if (ksi == NULL) 681 return (ENOMEM); 682 683 mutex_enter(p->p_lock); 684 685 /* 686 * SA processes can have no more than 1 sigwaiter. 687 */ 688 if ((p->p_sflag & PS_SA) != 0 && !LIST_EMPTY(&p->p_sigwaiters)) { 689 mutex_exit(p->p_lock); 690 error = EINVAL; 691 goto out; 692 } 693 694 if ((signum = sigget(&p->p_sigpend, ksi, 0, &l->l_sigwaitset)) == 0) 695 signum = sigget(&l->l_sigpend, ksi, 0, &l->l_sigwaitset); 696 697 if (signum != 0) { 698 /* 699 * We found a pending signal - copy it out to the user. 700 */ 701 mutex_exit(p->p_lock); 702 goto out; 703 } 704 705 /* 706 * Set up the sigwait list. 707 */ 708 l->l_sigwaited = ksi; 709 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 710 711 /* 712 * Wait for signal to arrive. We can either be woken up or time out. 713 */ 714 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 715 716 /* 717 * Need to find out if we woke as a result of lwp_wakeup() or a 718 * signal outside our wait set. 719 */ 720 if (l->l_sigwaited != NULL) { 721 if (error == EINTR) { 722 /* wakeup via _lwp_wakeup() */ 723 error = ECANCELED; 724 } else if (!error) { 725 /* spurious wakeup - arrange for syscall restart */ 726 error = ERESTART; 727 } 728 l->l_sigwaited = NULL; 729 LIST_REMOVE(l, l_sigwaiter); 730 } 731 732 mutex_exit(p->p_lock); 733 734 /* 735 * If the sleep was interrupted (either by signal or wakeup), update 736 * the timeout and copyout new value back. It would be used when 737 * the syscall would be restarted or called again. 738 */ 739 if (timo && (error == ERESTART || error == ECANCELED)) { 740 getnanouptime(&tsnow); 741 742 /* compute how much time has passed since start */ 743 timespecsub(&tsnow, &tsstart, &tsnow); 744 /* substract passed time from timeout */ 745 timespecsub(&ts, &tsnow, &ts); 746 747 if (ts.tv_sec < 0) 748 error = EAGAIN; 749 else { 750 /* copy updated timeout to userland */ 751 error = (*put_timeout)(&ts, SCARG(uap, timeout), 752 sizeof(ts)); 753 } 754 } 755 756 /* 757 * If a signal from the wait set arrived, copy it to userland. 758 * Copy only the used part of siginfo, the padding part is 759 * left unchanged (userland is not supposed to touch it anyway). 760 */ 761 out: 762 if (error == 0) 763 error = (*put_info)(&ksi->ksi_info, SCARG(uap, info), 764 sizeof(ksi->ksi_info)); 765 766 ksiginfo_free(ksi); 767 768 return error; 769 } 770