sys_sig.c revision 1.25
1 /* $NetBSD: sys_sig.c,v 1.25 2009/12/20 04:49:09 rmind 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 1.25 2009/12/20 04:49:09 rmind 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 int 85 sys___sigaction_sigtramp(struct lwp *l, 86 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, 122 register_t *retval) 123 { 124 /* { 125 syscallarg(int) how; 126 syscallarg(const sigset_t *) set; 127 syscallarg(sigset_t *) oset; 128 } */ 129 struct proc *p = l->l_proc; 130 sigset_t nss, oss; 131 int error; 132 133 if (SCARG(uap, set)) { 134 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 135 if (error) 136 return error; 137 } 138 mutex_enter(p->p_lock); 139 error = sigprocmask1(l, SCARG(uap, how), 140 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 141 mutex_exit(p->p_lock); 142 if (error) 143 return error; 144 if (SCARG(uap, oset)) { 145 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 146 if (error) 147 return error; 148 } 149 return 0; 150 } 151 152 int 153 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, 154 register_t *retval) 155 { 156 /* { 157 syscallarg(sigset_t *) set; 158 } */ 159 sigset_t ss; 160 161 sigpending1(l, &ss); 162 return copyout(&ss, SCARG(uap, set), sizeof(ss)); 163 } 164 165 /* 166 * Suspend process until signal, providing mask to be set in the meantime. 167 * Note nonstandard calling convention: libc stub passes mask, not pointer, 168 * to save a copyin. 169 */ 170 int 171 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, 172 register_t *retval) 173 { 174 /* { 175 syscallarg(const sigset_t *) set; 176 } */ 177 sigset_t ss; 178 int error; 179 180 if (SCARG(uap, set)) { 181 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 182 if (error) 183 return error; 184 } 185 return sigsuspend1(l, SCARG(uap, set) ? &ss : 0); 186 } 187 188 int 189 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, 190 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 int 217 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 218 { 219 /* { 220 syscallarg(int) pid; 221 syscallarg(int) signum; 222 } */ 223 struct proc *p; 224 ksiginfo_t ksi; 225 int signum = SCARG(uap, signum); 226 int error; 227 228 if ((u_int)signum >= NSIG) 229 return EINVAL; 230 KSI_INIT(&ksi); 231 ksi.ksi_signo = signum; 232 ksi.ksi_code = SI_USER; 233 ksi.ksi_pid = l->l_proc->p_pid; 234 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 235 if (SCARG(uap, pid) > 0) { 236 /* kill single process */ 237 mutex_enter(proc_lock); 238 if ((p = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) { 239 mutex_exit(proc_lock); 240 return ESRCH; 241 } 242 mutex_enter(p->p_lock); 243 error = kauth_authorize_process(l->l_cred, 244 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signum), 245 NULL, NULL); 246 if (!error && signum) { 247 kpsignal2(p, &ksi); 248 } 249 mutex_exit(p->p_lock); 250 mutex_exit(proc_lock); 251 return error; 252 } 253 switch (SCARG(uap, pid)) { 254 case -1: /* broadcast signal */ 255 return killpg1(l, &ksi, 0, 1); 256 case 0: /* signal own process group */ 257 return killpg1(l, &ksi, 0, 0); 258 default: /* negative explicit process group */ 259 return killpg1(l, &ksi, -SCARG(uap, pid), 0); 260 } 261 /* NOTREACHED */ 262 } 263 264 int 265 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, 266 register_t *retval) 267 { 268 /* { 269 syscallarg(struct __ucontext *) ucp; 270 } */ 271 struct proc *p = l->l_proc; 272 ucontext_t uc; 273 274 mutex_enter(p->p_lock); 275 getucontext(l, &uc); 276 mutex_exit(p->p_lock); 277 278 return copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp))); 279 } 280 281 int 282 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, 283 register_t *retval) 284 { 285 /* { 286 syscallarg(const ucontext_t *) ucp; 287 } */ 288 struct proc *p = l->l_proc; 289 ucontext_t uc; 290 int error; 291 292 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 293 if (error) 294 return error; 295 if ((uc.uc_flags & _UC_CPU) == 0) 296 return EINVAL; 297 mutex_enter(p->p_lock); 298 error = setucontext(l, &uc); 299 mutex_exit(p->p_lock); 300 if (error) 301 return error; 302 303 return EJUSTRETURN; 304 } 305 306 /* 307 * sigtimedwait(2) system call, used also for implementation 308 * of sigwaitinfo() and sigwait(). 309 * 310 * This only handles single LWP in signal wait. libpthread provides 311 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 312 */ 313 int 314 sys_____sigtimedwait50(struct lwp *l, 315 const struct sys_____sigtimedwait50_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 = l->l_proc; 561 562 if (ss) { 563 /* 564 * When returning from sigsuspend, we want 565 * the old mask to be restored after the 566 * signal handler has finished. Thus, we 567 * save it here and mark the sigctx structure 568 * to indicate this. 569 */ 570 mutex_enter(p->p_lock); 571 l->l_sigrestore = 1; 572 l->l_sigoldmask = l->l_sigmask; 573 l->l_sigmask = *ss; 574 sigminusset(&sigcantmask, &l->l_sigmask); 575 576 /* Check for pending signals when sleeping. */ 577 if (sigispending(l, 0)) { 578 lwp_lock(l); 579 l->l_flag |= LW_PENDSIG; 580 lwp_unlock(l); 581 } 582 mutex_exit(p->p_lock); 583 } 584 585 while (kpause("pause", true, 0, NULL) == 0) 586 ; 587 588 /* always return EINTR rather than ERESTART... */ 589 return EINTR; 590 } 591 592 int 593 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 594 struct sigaltstack *oss) 595 { 596 struct proc *p = l->l_proc; 597 int error = 0; 598 599 mutex_enter(p->p_lock); 600 601 if (oss) 602 *oss = l->l_sigstk; 603 604 if (nss) { 605 if (nss->ss_flags & ~SS_ALLBITS) 606 error = EINVAL; 607 else if (nss->ss_flags & SS_DISABLE) { 608 if (l->l_sigstk.ss_flags & SS_ONSTACK) 609 error = EINVAL; 610 } else if (nss->ss_size < MINSIGSTKSZ) 611 error = ENOMEM; 612 613 if (!error) 614 l->l_sigstk = *nss; 615 } 616 617 mutex_exit(p->p_lock); 618 619 return error; 620 } 621 622 int 623 __sigtimedwait1(struct lwp *l, const struct sys_____sigtimedwait50_args *uap, 624 register_t *retval, copyout_t storeinf, copyin_t fetchts, copyout_t storets) 625 { 626 /* { 627 syscallarg(const sigset_t *) set; 628 syscallarg(siginfo_t *) info; 629 syscallarg(struct timespec *) timeout; 630 } */ 631 struct proc *p = l->l_proc; 632 int error, signum, timo; 633 struct timespec ts, tsstart, tsnow; 634 ksiginfo_t ksi; 635 636 /* 637 * Calculate timeout, if it was specified. 638 */ 639 if (SCARG(uap, timeout)) { 640 error = (*fetchts)(SCARG(uap, timeout), &ts, sizeof(ts)); 641 if (error) 642 return error; 643 644 if ((error = itimespecfix(&ts)) != 0) 645 return error; 646 647 timo = tstohz(&ts); 648 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec != 0) 649 timo++; 650 651 /* 652 * Remember current uptime, it would be used in 653 * ECANCELED/ERESTART case. 654 */ 655 getnanouptime(&tsstart); 656 } else { 657 memset(&tsstart, 0, sizeof(tsstart)); /* XXXgcc */ 658 timo = 0; 659 } 660 661 error = copyin(SCARG(uap, set), &l->l_sigwaitset, 662 sizeof(l->l_sigwaitset)); 663 if (error) 664 return error; 665 666 /* 667 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 668 * SA_CANTMASK signals in waitset, we do this only for the below 669 * siglist check. 670 */ 671 sigminusset(&sigcantmask, &l->l_sigwaitset); 672 673 mutex_enter(p->p_lock); 674 675 /* SA processes can have no more than 1 sigwaiter. */ 676 if ((p->p_sflag & PS_SA) != 0 && !LIST_EMPTY(&p->p_sigwaiters)) { 677 mutex_exit(p->p_lock); 678 error = EINVAL; 679 goto out; 680 } 681 682 /* Check for pending signals in the process, if no - then in LWP. */ 683 if ((signum = sigget(&p->p_sigpend, &ksi, 0, &l->l_sigwaitset)) == 0) 684 signum = sigget(&l->l_sigpend, &ksi, 0, &l->l_sigwaitset); 685 686 if (signum != 0) { 687 /* If found a pending signal, just copy it out to the user. */ 688 mutex_exit(p->p_lock); 689 goto out; 690 } 691 692 /* 693 * Set up the sigwait list and wait for signal to arrive. 694 * We can either be woken up or time out. 695 */ 696 l->l_sigwaited = &ksi; 697 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 698 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 699 700 /* 701 * Need to find out if we woke as a result of _lwp_wakeup() or a 702 * signal outside our wait set. 703 */ 704 if (l->l_sigwaited != NULL) { 705 if (error == EINTR) { 706 /* Wakeup via _lwp_wakeup(). */ 707 error = ECANCELED; 708 } else if (!error) { 709 /* Spurious wakeup - arrange for syscall restart. */ 710 error = ERESTART; 711 } 712 l->l_sigwaited = NULL; 713 LIST_REMOVE(l, l_sigwaiter); 714 } 715 mutex_exit(p->p_lock); 716 717 /* 718 * If the sleep was interrupted (either by signal or wakeup), update 719 * the timeout and copyout new value back. It would be used when 720 * the syscall would be restarted or called again. 721 */ 722 if (timo && (error == ERESTART || error == ECANCELED)) { 723 getnanouptime(&tsnow); 724 725 /* Compute how much time has passed since start. */ 726 timespecsub(&tsnow, &tsstart, &tsnow); 727 728 /* Substract passed time from timeout. */ 729 timespecsub(&ts, &tsnow, &ts); 730 731 if (ts.tv_sec < 0) 732 error = EAGAIN; 733 else { 734 /* Copy updated timeout to userland. */ 735 error = (*storets)(&ts, SCARG(uap, timeout), 736 sizeof(ts)); 737 } 738 } 739 out: 740 /* 741 * If a signal from the wait set arrived, copy it to userland. 742 * Copy only the used part of siginfo, the padding part is 743 * left unchanged (userland is not supposed to touch it anyway). 744 */ 745 if (error == 0) { 746 error = (*storeinf)(&ksi.ksi_info, SCARG(uap, info), 747 sizeof(ksi.ksi_info)); 748 } 749 return error; 750 } 751
Indexes created Mon Sep 22 05:09:51 GMT 2025