sys_sig.c revision 1.14
1 /* $NetBSD: sys_sig.c,v 1.14 2008/04/24 18:39:24 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (c) 1982, 1986, 1989, 1991, 1993 41 * The Regents of the University of California. All rights reserved. 42 * (c) UNIX System Laboratories, Inc. 43 * All or some portions of this file are derived from material licensed 44 * to the University of California by American Telephone and Telegraph 45 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 46 * the permission of UNIX System Laboratories, Inc. 47 * 48 * Redistribution and use in source and binary forms, with or without 49 * modification, are permitted provided that the following conditions 50 * are met: 51 * 1. Redistributions of source code must retain the above copyright 52 * notice, this list of conditions and the following disclaimer. 53 * 2. Redistributions in binary form must reproduce the above copyright 54 * notice, this list of conditions and the following disclaimer in the 55 * documentation and/or other materials provided with the distribution. 56 * 3. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 73 */ 74 75 #include <sys/cdefs.h> 76 __KERNEL_RCSID(0, "$NetBSD: sys_sig.c,v 1.14 2008/04/24 18:39:24 ad Exp $"); 77 78 #include "opt_ptrace.h" 79 #include "opt_compat_netbsd.h" 80 #include "opt_compat_netbsd32.h" 81 82 #include <sys/param.h> 83 #include <sys/kernel.h> 84 #include <sys/signalvar.h> 85 #include <sys/proc.h> 86 #include <sys/pool.h> 87 #include <sys/syscallargs.h> 88 #include <sys/kauth.h> 89 #include <sys/wait.h> 90 #include <sys/kmem.h> 91 92 #ifdef COMPAT_16 93 /* ARGSUSED */ 94 int 95 compat_16_sys___sigaction14(struct lwp *l, const struct compat_16_sys___sigaction14_args *uap, register_t *retval) 96 { 97 /* { 98 syscallarg(int) signum; 99 syscallarg(const struct sigaction *) nsa; 100 syscallarg(struct sigaction *) osa; 101 } */ 102 struct sigaction nsa, osa; 103 int error; 104 105 if (SCARG(uap, nsa)) { 106 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 107 if (error) 108 return (error); 109 } 110 error = sigaction1(l, SCARG(uap, signum), 111 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 112 NULL, 0); 113 if (error) 114 return (error); 115 if (SCARG(uap, osa)) { 116 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 117 if (error) 118 return (error); 119 } 120 return (0); 121 } 122 #endif 123 124 /* ARGSUSED */ 125 int 126 sys___sigaction_sigtramp(struct lwp *l, const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 127 { 128 /* { 129 syscallarg(int) signum; 130 syscallarg(const struct sigaction *) nsa; 131 syscallarg(struct sigaction *) osa; 132 syscallarg(void *) tramp; 133 syscallarg(int) vers; 134 } */ 135 struct sigaction nsa, osa; 136 int error; 137 138 if (SCARG(uap, nsa)) { 139 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 140 if (error) 141 return (error); 142 } 143 error = sigaction1(l, SCARG(uap, signum), 144 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 145 SCARG(uap, tramp), SCARG(uap, vers)); 146 if (error) 147 return (error); 148 if (SCARG(uap, osa)) { 149 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 150 if (error) 151 return (error); 152 } 153 return (0); 154 } 155 156 /* 157 * Manipulate signal mask. Note that we receive new mask, not pointer, and 158 * return old mask as return value; the library stub does the rest. 159 */ 160 int 161 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, register_t *retval) 162 { 163 /* { 164 syscallarg(int) how; 165 syscallarg(const sigset_t *) set; 166 syscallarg(sigset_t *) oset; 167 } */ 168 struct proc *p = l->l_proc; 169 sigset_t nss, oss; 170 int error; 171 172 if (SCARG(uap, set)) { 173 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 174 if (error) 175 return (error); 176 } 177 mutex_enter(p->p_lock); 178 error = sigprocmask1(l, SCARG(uap, how), 179 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 180 mutex_exit(p->p_lock); 181 if (error) 182 return (error); 183 if (SCARG(uap, oset)) { 184 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 185 if (error) 186 return (error); 187 } 188 return (0); 189 } 190 191 /* ARGSUSED */ 192 int 193 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, register_t *retval) 194 { 195 /* { 196 syscallarg(sigset_t *) set; 197 } */ 198 sigset_t ss; 199 200 sigpending1(l, &ss); 201 return (copyout(&ss, SCARG(uap, set), sizeof(ss))); 202 } 203 204 /* 205 * Suspend process until signal, providing mask to be set in the meantime. 206 * Note nonstandard calling convention: libc stub passes mask, not pointer, 207 * to save a copyin. 208 */ 209 /* ARGSUSED */ 210 int 211 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, register_t *retval) 212 { 213 /* { 214 syscallarg(const sigset_t *) set; 215 } */ 216 sigset_t ss; 217 int error; 218 219 if (SCARG(uap, set)) { 220 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 221 if (error) 222 return (error); 223 } 224 225 return (sigsuspend1(l, SCARG(uap, set) ? &ss : 0)); 226 } 227 228 /* ARGSUSED */ 229 int 230 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, register_t *retval) 231 { 232 /* { 233 syscallarg(const struct sigaltstack *) nss; 234 syscallarg(struct sigaltstack *) oss; 235 } */ 236 struct sigaltstack nss, oss; 237 int error; 238 239 if (SCARG(uap, nss)) { 240 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 241 if (error) 242 return (error); 243 } 244 error = sigaltstack1(l, 245 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 246 if (error) 247 return (error); 248 if (SCARG(uap, oss)) { 249 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 250 if (error) 251 return (error); 252 } 253 return (0); 254 } 255 256 /* ARGSUSED */ 257 int 258 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 259 { 260 /* { 261 syscallarg(int) pid; 262 syscallarg(int) signum; 263 } */ 264 struct proc *p; 265 ksiginfo_t ksi; 266 int signum = SCARG(uap, signum); 267 int error; 268 269 if ((u_int)signum >= NSIG) 270 return (EINVAL); 271 KSI_INIT(&ksi); 272 ksi.ksi_signo = signum; 273 ksi.ksi_code = SI_USER; 274 ksi.ksi_pid = l->l_proc->p_pid; 275 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 276 if (SCARG(uap, pid) > 0) { 277 /* kill single process */ 278 mutex_enter(proc_lock); 279 if ((p = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) { 280 mutex_exit(proc_lock); 281 return (ESRCH); 282 } 283 mutex_enter(p->p_lock); 284 error = kauth_authorize_process(l->l_cred, 285 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signum), 286 NULL, NULL); 287 if (!error && signum) { 288 kpsignal2(p, &ksi); 289 } 290 mutex_exit(p->p_lock); 291 mutex_exit(proc_lock); 292 return (error); 293 } 294 switch (SCARG(uap, pid)) { 295 case -1: /* broadcast signal */ 296 return (killpg1(l, &ksi, 0, 1)); 297 case 0: /* signal own process group */ 298 return (killpg1(l, &ksi, 0, 0)); 299 default: /* negative explicit process group */ 300 return (killpg1(l, &ksi, -SCARG(uap, pid), 0)); 301 } 302 /* NOTREACHED */ 303 } 304 305 /* ARGSUSED */ 306 int 307 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, register_t *retval) 308 { 309 /* { 310 syscallarg(struct __ucontext *) ucp; 311 } */ 312 struct proc *p = l->l_proc; 313 ucontext_t uc; 314 315 mutex_enter(p->p_lock); 316 getucontext(l, &uc); 317 mutex_exit(p->p_lock); 318 319 return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp)))); 320 } 321 322 /* ARGSUSED */ 323 int 324 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, register_t *retval) 325 { 326 /* { 327 syscallarg(const ucontext_t *) ucp; 328 } */ 329 struct proc *p = l->l_proc; 330 ucontext_t uc; 331 int error; 332 333 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 334 if (error) 335 return (error); 336 if (!(uc.uc_flags & _UC_CPU)) 337 return (EINVAL); 338 mutex_enter(p->p_lock); 339 error = setucontext(l, &uc); 340 mutex_exit(p->p_lock); 341 if (error) 342 return (error); 343 344 return (EJUSTRETURN); 345 } 346 347 /* 348 * sigtimedwait(2) system call, used also for implementation 349 * of sigwaitinfo() and sigwait(). 350 * 351 * This only handles single LWP in signal wait. libpthread provides 352 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 353 */ 354 int 355 sys___sigtimedwait(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval) 356 { 357 358 return __sigtimedwait1(l, uap, retval, copyout, copyin, copyout); 359 } 360 361 int 362 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 363 struct sigaction *osa, const void *tramp, int vers) 364 { 365 struct proc *p; 366 struct sigacts *ps; 367 sigset_t tset; 368 int prop, error; 369 ksiginfoq_t kq; 370 371 if (signum <= 0 || signum >= NSIG) 372 return (EINVAL); 373 374 p = l->l_proc; 375 error = 0; 376 ksiginfo_queue_init(&kq); 377 378 /* 379 * Trampoline ABI version 0 is reserved for the legacy kernel 380 * provided on-stack trampoline. Conversely, if we are using a 381 * non-0 ABI version, we must have a trampoline. Only validate the 382 * vers if a new sigaction was supplied. Emulations use legacy 383 * kernel trampolines with version 0, alternatively check for that 384 * too. 385 */ 386 if ((vers != 0 && tramp == NULL) || 387 #ifdef SIGTRAMP_VALID 388 (nsa != NULL && 389 ((vers == 0) ? 390 (p->p_emul->e_sigcode == NULL) : 391 !SIGTRAMP_VALID(vers))) || 392 #endif 393 (vers == 0 && tramp != NULL)) { 394 return (EINVAL); 395 } 396 397 mutex_enter(p->p_lock); 398 399 ps = p->p_sigacts; 400 if (osa) 401 *osa = SIGACTION_PS(ps, signum); 402 if (!nsa) 403 goto out; 404 405 prop = sigprop[signum]; 406 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 407 error = EINVAL; 408 goto out; 409 } 410 411 SIGACTION_PS(ps, signum) = *nsa; 412 ps->sa_sigdesc[signum].sd_tramp = tramp; 413 ps->sa_sigdesc[signum].sd_vers = vers; 414 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 415 416 if ((prop & SA_NORESET) != 0) 417 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 418 419 if (signum == SIGCHLD) { 420 if (nsa->sa_flags & SA_NOCLDSTOP) 421 p->p_sflag |= PS_NOCLDSTOP; 422 else 423 p->p_sflag &= ~PS_NOCLDSTOP; 424 if (nsa->sa_flags & SA_NOCLDWAIT) { 425 /* 426 * Paranoia: since SA_NOCLDWAIT is implemented by 427 * reparenting the dying child to PID 1 (and trust 428 * it to reap the zombie), PID 1 itself is forbidden 429 * to set SA_NOCLDWAIT. 430 */ 431 if (p->p_pid == 1) 432 p->p_flag &= ~PK_NOCLDWAIT; 433 else 434 p->p_flag |= PK_NOCLDWAIT; 435 } else 436 p->p_flag &= ~PK_NOCLDWAIT; 437 438 if (nsa->sa_handler == SIG_IGN) { 439 /* 440 * Paranoia: same as above. 441 */ 442 if (p->p_pid == 1) 443 p->p_flag &= ~PK_CLDSIGIGN; 444 else 445 p->p_flag |= PK_CLDSIGIGN; 446 } else 447 p->p_flag &= ~PK_CLDSIGIGN; 448 } 449 450 if ((nsa->sa_flags & SA_NODEFER) == 0) 451 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 452 else 453 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 454 455 /* 456 * Set bit in p_sigctx.ps_sigignore for signals that are set to 457 * SIG_IGN, and for signals set to SIG_DFL where the default is to 458 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 459 * we have to restart the process. 460 */ 461 if (nsa->sa_handler == SIG_IGN || 462 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 463 /* Never to be seen again. */ 464 sigemptyset(&tset); 465 sigaddset(&tset, signum); 466 sigclearall(p, &tset, &kq); 467 if (signum != SIGCONT) { 468 /* Easier in psignal */ 469 sigaddset(&p->p_sigctx.ps_sigignore, signum); 470 } 471 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 472 } else { 473 sigdelset(&p->p_sigctx.ps_sigignore, signum); 474 if (nsa->sa_handler == SIG_DFL) 475 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 476 else 477 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 478 } 479 480 /* 481 * Previously held signals may now have become visible. Ensure that 482 * we check for them before returning to userspace. 483 */ 484 if (sigispending(l, 0)) { 485 lwp_lock(l); 486 l->l_flag |= LW_PENDSIG; 487 lwp_unlock(l); 488 } 489 out: 490 mutex_exit(p->p_lock); 491 ksiginfo_queue_drain(&kq); 492 493 return (error); 494 } 495 496 int 497 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 498 { 499 int more; 500 501 KASSERT(mutex_owned(l->l_proc->p_lock)); 502 503 if (oss) 504 *oss = l->l_sigmask; 505 if (nss) { 506 switch (how) { 507 case SIG_BLOCK: 508 sigplusset(nss, &l->l_sigmask); 509 more = 0; 510 break; 511 case SIG_UNBLOCK: 512 sigminusset(nss, &l->l_sigmask); 513 more = 1; 514 break; 515 case SIG_SETMASK: 516 l->l_sigmask = *nss; 517 more = 1; 518 break; 519 default: 520 return (EINVAL); 521 } 522 sigminusset(&sigcantmask, &l->l_sigmask); 523 if (more && sigispending(l, 0)) { 524 /* 525 * Check for pending signals on return to user. 526 */ 527 lwp_lock(l); 528 l->l_flag |= LW_PENDSIG; 529 lwp_unlock(l); 530 } 531 } 532 533 return (0); 534 } 535 536 void 537 sigpending1(struct lwp *l, sigset_t *ss) 538 { 539 struct proc *p = l->l_proc; 540 541 mutex_enter(p->p_lock); 542 *ss = l->l_sigpend.sp_set; 543 sigplusset(&p->p_sigpend.sp_set, ss); 544 sigminusset(&l->l_sigmask, ss); 545 mutex_exit(p->p_lock); 546 } 547 548 int 549 sigsuspend1(struct lwp *l, const sigset_t *ss) 550 { 551 struct proc *p; 552 553 p = l->l_proc; 554 555 if (ss) { 556 /* 557 * When returning from sigsuspend, we want 558 * the old mask to be restored after the 559 * signal handler has finished. Thus, we 560 * save it here and mark the sigctx structure 561 * to indicate this. 562 */ 563 mutex_enter(p->p_lock); 564 l->l_sigrestore = 1; 565 l->l_sigoldmask = l->l_sigmask; 566 l->l_sigmask = *ss; 567 sigminusset(&sigcantmask, &l->l_sigmask); 568 569 /* Check for pending signals when sleeping. */ 570 if (sigispending(l, 0)) { 571 lwp_lock(l); 572 l->l_flag |= LW_PENDSIG; 573 lwp_unlock(l); 574 } 575 mutex_exit(p->p_lock); 576 } 577 578 while (kpause("pause", true, 0, NULL) == 0) 579 ; 580 581 /* always return EINTR rather than ERESTART... */ 582 return (EINTR); 583 } 584 585 int 586 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 587 struct sigaltstack *oss) 588 { 589 struct proc *p = l->l_proc; 590 int error = 0; 591 592 mutex_enter(p->p_lock); 593 594 if (oss) 595 *oss = l->l_sigstk; 596 597 if (nss) { 598 if (nss->ss_flags & ~SS_ALLBITS) 599 error = EINVAL; 600 else if (nss->ss_flags & SS_DISABLE) { 601 if (l->l_sigstk.ss_flags & SS_ONSTACK) 602 error = EINVAL; 603 } else if (nss->ss_size < MINSIGSTKSZ) 604 error = ENOMEM; 605 606 if (!error) 607 l->l_sigstk = *nss; 608 } 609 610 mutex_exit(p->p_lock); 611 612 return (error); 613 } 614 615 int 616 __sigtimedwait1(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval, 617 copyout_t put_info, copyin_t fetch_timeout, copyout_t put_timeout) 618 { 619 /* { 620 syscallarg(const sigset_t *) set; 621 syscallarg(siginfo_t *) info; 622 syscallarg(struct timespec *) timeout; 623 } */ 624 struct proc *p = l->l_proc; 625 int error, signum; 626 int timo = 0; 627 struct timespec ts, tsstart, tsnow; 628 ksiginfo_t *ksi; 629 630 memset(&tsstart, 0, sizeof tsstart); /* XXX gcc */ 631 632 /* 633 * Calculate timeout, if it was specified. 634 */ 635 if (SCARG(uap, timeout)) { 636 uint64_t ms; 637 638 if ((error = (*fetch_timeout)(SCARG(uap, timeout), &ts, sizeof(ts)))) 639 return (error); 640 641 ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000); 642 timo = mstohz(ms); 643 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0) 644 timo = 1; 645 if (timo <= 0) 646 return (EAGAIN); 647 648 /* 649 * Remember current uptime, it would be used in 650 * ECANCELED/ERESTART case. 651 */ 652 getnanouptime(&tsstart); 653 } 654 655 error = copyin(SCARG(uap, set), &l->l_sigwaitset, 656 sizeof(l->l_sigwaitset)); 657 if (error != 0) 658 return (error); 659 660 /* 661 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 662 * SA_CANTMASK signals in waitset, we do this only for the below 663 * siglist check. 664 */ 665 sigminusset(&sigcantmask, &l->l_sigwaitset); 666 667 /* 668 * Allocate a ksi up front. We can't sleep with the mutex held. 669 */ 670 ksi = ksiginfo_alloc(p, NULL, PR_WAITOK); 671 if (ksi == NULL) 672 return (ENOMEM); 673 674 mutex_enter(p->p_lock); 675 676 if ((signum = sigget(&p->p_sigpend, ksi, 0, &l->l_sigwaitset)) == 0) 677 signum = sigget(&l->l_sigpend, ksi, 0, &l->l_sigwaitset); 678 679 if (signum != 0) { 680 /* 681 * We found a pending signal - copy it out to the user. 682 */ 683 mutex_exit(p->p_lock); 684 goto out; 685 } 686 687 /* 688 * Set up the sigwait list. 689 */ 690 l->l_sigwaited = ksi; 691 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 692 693 /* 694 * Wait for signal to arrive. We can either be woken up or time out. 695 */ 696 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 697 698 /* 699 * Need to find out if we woke as a result of lwp_wakeup() or a 700 * signal outside our wait set. 701 */ 702 if (l->l_sigwaited != NULL) { 703 if (error == EINTR) { 704 /* wakeup via _lwp_wakeup() */ 705 error = ECANCELED; 706 } else if (!error) { 707 /* spurious wakeup - arrange for syscall restart */ 708 error = ERESTART; 709 } 710 l->l_sigwaited = NULL; 711 LIST_REMOVE(l, l_sigwaiter); 712 } 713 714 mutex_exit(p->p_lock); 715 716 /* 717 * If the sleep was interrupted (either by signal or wakeup), update 718 * the timeout and copyout new value back. It would be used when 719 * the syscall would be restarted or called again. 720 */ 721 if (timo && (error == ERESTART || error == ECANCELED)) { 722 getnanouptime(&tsnow); 723 724 /* compute how much time has passed since start */ 725 timespecsub(&tsnow, &tsstart, &tsnow); 726 /* substract passed time from timeout */ 727 timespecsub(&ts, &tsnow, &ts); 728 729 if (ts.tv_sec < 0) 730 error = EAGAIN; 731 else { 732 /* copy updated timeout to userland */ 733 error = (*put_timeout)(&ts, SCARG(uap, timeout), 734 sizeof(ts)); 735 } 736 } 737 738 /* 739 * If a signal from the wait set arrived, copy it to userland. 740 * Copy only the used part of siginfo, the padding part is 741 * left unchanged (userland is not supposed to touch it anyway). 742 */ 743 out: 744 if (error == 0) 745 error = (*put_info)(&ksi->ksi_info, SCARG(uap, info), 746 sizeof(ksi->ksi_info)); 747 748 ksiginfo_free(ksi); 749 750 return error; 751 } 752
Indexes created Fri Sep 26 08:10:20 GMT 2025