sys_sig.c revision 1.15.2.4
1 /* $NetBSD: sys_sig.c,v 1.15.2.4 2008/05/28 06:33:24 wrstuden 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 1.15.2.4 2008/05/28 06:33:24 wrstuden 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/sa.h> 81 #include <sys/savar.h> 82 #include <sys/syscallargs.h> 83 #include <sys/kauth.h> 84 #include <sys/wait.h> 85 #include <sys/kmem.h> 86 87 #ifdef COMPAT_16 88 /* ARGSUSED */ 89 int 90 compat_16_sys___sigaction14(struct lwp *l, const struct compat_16_sys___sigaction14_args *uap, register_t *retval) 91 { 92 /* { 93 syscallarg(int) signum; 94 syscallarg(const struct sigaction *) nsa; 95 syscallarg(struct sigaction *) osa; 96 } */ 97 struct sigaction nsa, osa; 98 int error; 99 100 if (SCARG(uap, nsa)) { 101 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 102 if (error) 103 return (error); 104 } 105 error = sigaction1(l, SCARG(uap, signum), 106 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 107 NULL, 0); 108 if (error) 109 return (error); 110 if (SCARG(uap, osa)) { 111 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 112 if (error) 113 return (error); 114 } 115 return (0); 116 } 117 #endif 118 119 /* ARGSUSED */ 120 int 121 sys___sigaction_sigtramp(struct lwp *l, const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 122 { 123 /* { 124 syscallarg(int) signum; 125 syscallarg(const struct sigaction *) nsa; 126 syscallarg(struct sigaction *) osa; 127 syscallarg(void *) tramp; 128 syscallarg(int) vers; 129 } */ 130 struct sigaction nsa, osa; 131 int error; 132 133 if (SCARG(uap, nsa)) { 134 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 135 if (error) 136 return (error); 137 } 138 error = sigaction1(l, SCARG(uap, signum), 139 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 140 SCARG(uap, tramp), SCARG(uap, vers)); 141 if (error) 142 return (error); 143 if (SCARG(uap, osa)) { 144 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 145 if (error) 146 return (error); 147 } 148 return (0); 149 } 150 151 /* 152 * Manipulate signal mask. Note that we receive new mask, not pointer, and 153 * return old mask as return value; the library stub does the rest. 154 */ 155 int 156 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, register_t *retval) 157 { 158 /* { 159 syscallarg(int) how; 160 syscallarg(const sigset_t *) set; 161 syscallarg(sigset_t *) oset; 162 } */ 163 struct proc *p = l->l_proc; 164 sigset_t nss, oss; 165 int error; 166 167 if (SCARG(uap, set)) { 168 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 169 if (error) 170 return (error); 171 } 172 mutex_enter(p->p_lock); 173 error = sigprocmask1(l, SCARG(uap, how), 174 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 175 mutex_exit(p->p_lock); 176 if (error) 177 return (error); 178 if (SCARG(uap, oset)) { 179 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 180 if (error) 181 return (error); 182 } 183 return (0); 184 } 185 186 /* ARGSUSED */ 187 int 188 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, register_t *retval) 189 { 190 /* { 191 syscallarg(sigset_t *) set; 192 } */ 193 sigset_t ss; 194 195 sigpending1(l, &ss); 196 return (copyout(&ss, SCARG(uap, set), sizeof(ss))); 197 } 198 199 /* 200 * Suspend process until signal, providing mask to be set in the meantime. 201 * Note nonstandard calling convention: libc stub passes mask, not pointer, 202 * to save a copyin. 203 */ 204 /* ARGSUSED */ 205 int 206 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, register_t *retval) 207 { 208 /* { 209 syscallarg(const sigset_t *) set; 210 } */ 211 sigset_t ss; 212 int error; 213 214 if (SCARG(uap, set)) { 215 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 216 if (error) 217 return (error); 218 } 219 220 return (sigsuspend1(l, SCARG(uap, set) ? &ss : 0)); 221 } 222 223 /* ARGSUSED */ 224 int 225 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, register_t *retval) 226 { 227 /* { 228 syscallarg(const struct sigaltstack *) nss; 229 syscallarg(struct sigaltstack *) oss; 230 } */ 231 struct sigaltstack nss, oss; 232 int error; 233 234 if (SCARG(uap, nss)) { 235 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 236 if (error) 237 return (error); 238 } 239 error = sigaltstack1(l, 240 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 241 if (error) 242 return (error); 243 if (SCARG(uap, oss)) { 244 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 245 if (error) 246 return (error); 247 } 248 return (0); 249 } 250 251 /* ARGSUSED */ 252 int 253 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 254 { 255 /* { 256 syscallarg(int) pid; 257 syscallarg(int) signum; 258 } */ 259 struct proc *p; 260 ksiginfo_t ksi; 261 int signum = SCARG(uap, signum); 262 int error; 263 264 if ((u_int)signum >= NSIG) 265 return (EINVAL); 266 KSI_INIT(&ksi); 267 ksi.ksi_signo = signum; 268 ksi.ksi_code = SI_USER; 269 ksi.ksi_pid = l->l_proc->p_pid; 270 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 271 if (SCARG(uap, pid) > 0) { 272 /* kill single process */ 273 mutex_enter(proc_lock); 274 if ((p = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) { 275 mutex_exit(proc_lock); 276 return (ESRCH); 277 } 278 mutex_enter(p->p_lock); 279 error = kauth_authorize_process(l->l_cred, 280 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signum), 281 NULL, NULL); 282 if (!error && signum) { 283 kpsignal2(p, &ksi); 284 } 285 mutex_exit(p->p_lock); 286 mutex_exit(proc_lock); 287 return (error); 288 } 289 switch (SCARG(uap, pid)) { 290 case -1: /* broadcast signal */ 291 return (killpg1(l, &ksi, 0, 1)); 292 case 0: /* signal own process group */ 293 return (killpg1(l, &ksi, 0, 0)); 294 default: /* negative explicit process group */ 295 return (killpg1(l, &ksi, -SCARG(uap, pid), 0)); 296 } 297 /* NOTREACHED */ 298 } 299 300 /* ARGSUSED */ 301 int 302 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, register_t *retval) 303 { 304 /* { 305 syscallarg(struct __ucontext *) ucp; 306 } */ 307 struct proc *p = l->l_proc; 308 ucontext_t uc; 309 310 mutex_enter(p->p_lock); 311 getucontext(l, &uc); 312 mutex_exit(p->p_lock); 313 314 return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp)))); 315 } 316 317 /* ARGSUSED */ 318 int 319 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, register_t *retval) 320 { 321 /* { 322 syscallarg(const ucontext_t *) ucp; 323 } */ 324 struct proc *p = l->l_proc; 325 ucontext_t uc; 326 int error; 327 328 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 329 if (error) 330 return (error); 331 if (!(uc.uc_flags & _UC_CPU)) 332 return (EINVAL); 333 mutex_enter(p->p_lock); 334 error = setucontext(l, &uc); 335 mutex_exit(p->p_lock); 336 if (error) 337 return (error); 338 339 return (EJUSTRETURN); 340 } 341 342 /* 343 * sigtimedwait(2) system call, used also for implementation 344 * of sigwaitinfo() and sigwait(). 345 * 346 * This only handles single LWP in signal wait. libpthread provides 347 * it's own sigtimedwait() wrapper to DTRT WRT individual threads. 348 */ 349 int 350 sys___sigtimedwait(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval) 351 { 352 353 return __sigtimedwait1(l, uap, retval, copyout, copyin, copyout); 354 } 355 356 int 357 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 358 struct sigaction *osa, const void *tramp, int vers) 359 { 360 struct proc *p; 361 struct sigacts *ps; 362 sigset_t tset; 363 int prop, error; 364 ksiginfoq_t kq; 365 366 if (signum <= 0 || signum >= NSIG) 367 return (EINVAL); 368 369 p = l->l_proc; 370 error = 0; 371 ksiginfo_queue_init(&kq); 372 373 /* 374 * Trampoline ABI version 0 is reserved for the legacy kernel 375 * provided on-stack trampoline. Conversely, if we are using a 376 * non-0 ABI version, we must have a trampoline. Only validate the 377 * vers if a new sigaction was supplied. Emulations use legacy 378 * kernel trampolines with version 0, alternatively check for that 379 * too. 380 */ 381 if ((vers != 0 && tramp == NULL) || 382 #ifdef SIGTRAMP_VALID 383 (nsa != NULL && 384 ((vers == 0) ? 385 (p->p_emul->e_sigcode == NULL) : 386 !SIGTRAMP_VALID(vers))) || 387 #endif 388 (vers == 0 && tramp != NULL)) { 389 return (EINVAL); 390 } 391 392 mutex_enter(p->p_lock); 393 394 ps = p->p_sigacts; 395 if (osa) 396 *osa = SIGACTION_PS(ps, signum); 397 if (!nsa) 398 goto out; 399 400 prop = sigprop[signum]; 401 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 402 error = EINVAL; 403 goto out; 404 } 405 406 SIGACTION_PS(ps, signum) = *nsa; 407 ps->sa_sigdesc[signum].sd_tramp = tramp; 408 ps->sa_sigdesc[signum].sd_vers = vers; 409 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 410 411 if ((prop & SA_NORESET) != 0) 412 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 413 414 if (signum == SIGCHLD) { 415 if (nsa->sa_flags & SA_NOCLDSTOP) 416 p->p_sflag |= PS_NOCLDSTOP; 417 else 418 p->p_sflag &= ~PS_NOCLDSTOP; 419 if (nsa->sa_flags & SA_NOCLDWAIT) { 420 /* 421 * Paranoia: since SA_NOCLDWAIT is implemented by 422 * reparenting the dying child to PID 1 (and trust 423 * it to reap the zombie), PID 1 itself is forbidden 424 * to set SA_NOCLDWAIT. 425 */ 426 if (p->p_pid == 1) 427 p->p_flag &= ~PK_NOCLDWAIT; 428 else 429 p->p_flag |= PK_NOCLDWAIT; 430 } else 431 p->p_flag &= ~PK_NOCLDWAIT; 432 433 if (nsa->sa_handler == SIG_IGN) { 434 /* 435 * Paranoia: same as above. 436 */ 437 if (p->p_pid == 1) 438 p->p_flag &= ~PK_CLDSIGIGN; 439 else 440 p->p_flag |= PK_CLDSIGIGN; 441 } else 442 p->p_flag &= ~PK_CLDSIGIGN; 443 } 444 445 if ((nsa->sa_flags & SA_NODEFER) == 0) 446 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 447 else 448 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 449 450 /* 451 * Set bit in p_sigctx.ps_sigignore for signals that are set to 452 * SIG_IGN, and for signals set to SIG_DFL where the default is to 453 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 454 * we have to restart the process. 455 */ 456 if (nsa->sa_handler == SIG_IGN || 457 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 458 /* Never to be seen again. */ 459 sigemptyset(&tset); 460 sigaddset(&tset, signum); 461 sigclearall(p, &tset, &kq); 462 if (signum != SIGCONT) { 463 /* Easier in psignal */ 464 sigaddset(&p->p_sigctx.ps_sigignore, signum); 465 } 466 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 467 } else { 468 sigdelset(&p->p_sigctx.ps_sigignore, signum); 469 if (nsa->sa_handler == SIG_DFL) 470 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 471 else 472 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 473 } 474 475 /* 476 * Previously held signals may now have become visible. Ensure that 477 * we check for them before returning to userspace. 478 */ 479 if (sigispending(l, 0)) { 480 lwp_lock(l); 481 l->l_flag |= LW_PENDSIG; 482 lwp_unlock(l); 483 } 484 out: 485 mutex_exit(p->p_lock); 486 ksiginfo_queue_drain(&kq); 487 488 return (error); 489 } 490 491 int 492 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 493 { 494 int more; 495 struct proc *p = l->l_proc; 496 sigset_t *mask; 497 mask = (p->p_sa != NULL) ? &p->p_sa->sa_sigmask : &l->l_sigmask; 498 499 KASSERT(mutex_owned(p->p_lock)); 500 501 if (oss) 502 *oss = *mask; 503 if (nss) { 504 switch (how) { 505 case SIG_BLOCK: 506 sigplusset(nss, mask); 507 more = 0; 508 break; 509 case SIG_UNBLOCK: 510 sigminusset(nss, mask); 511 more = 1; 512 break; 513 case SIG_SETMASK: 514 *mask = *nss; 515 more = 1; 516 break; 517 default: 518 return (EINVAL); 519 } 520 sigminusset(&sigcantmask, mask); 521 if (more && sigispending(l, 0)) { 522 /* 523 * Check for pending signals on return to user. 524 */ 525 lwp_lock(l); 526 l->l_flag |= LW_PENDSIG; 527 lwp_unlock(l); 528 } 529 } 530 531 return (0); 532 } 533 534 void 535 sigpending1(struct lwp *l, sigset_t *ss) 536 { 537 struct proc *p = l->l_proc; 538 539 mutex_enter(p->p_lock); 540 *ss = l->l_sigpend.sp_set; 541 sigplusset(&p->p_sigpend.sp_set, ss); 542 if (p->p_sa) 543 sigminusset(&p->p_sa->sa_sigmask, ss); 544 else 545 sigminusset(&l->l_sigmask, ss); 546 mutex_exit(p->p_lock); 547 } 548 549 int 550 sigsuspend1(struct lwp *l, const sigset_t *ss) 551 { 552 struct proc *p; 553 554 p = l->l_proc; 555 556 if (ss) { 557 /* 558 * When returning from sigsuspend, we want 559 * the old mask to be restored after the 560 * signal handler has finished. Thus, we 561 * save it here and mark the sigctx structure 562 * to indicate this. 563 */ 564 mutex_enter(p->p_lock); 565 l->l_sigrestore = 1; 566 l->l_sigoldmask = l->l_sigmask; 567 l->l_sigmask = *ss; 568 sigminusset(&sigcantmask, &l->l_sigmask); 569 570 /* Check for pending signals when sleeping. */ 571 if (sigispending(l, 0)) { 572 lwp_lock(l); 573 l->l_flag |= LW_PENDSIG; 574 lwp_unlock(l); 575 } 576 mutex_exit(p->p_lock); 577 } 578 579 while (kpause("pause", true, 0, NULL) == 0) 580 ; 581 582 /* always return EINTR rather than ERESTART... */ 583 return (EINTR); 584 } 585 586 int 587 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 588 struct sigaltstack *oss) 589 { 590 struct proc *p = l->l_proc; 591 int error = 0; 592 593 mutex_enter(p->p_lock); 594 595 if (oss) 596 *oss = l->l_sigstk; 597 598 if (nss) { 599 if (nss->ss_flags & ~SS_ALLBITS) 600 error = EINVAL; 601 else if (nss->ss_flags & SS_DISABLE) { 602 if (l->l_sigstk.ss_flags & SS_ONSTACK) 603 error = EINVAL; 604 } else if (nss->ss_size < MINSIGSTKSZ) 605 error = ENOMEM; 606 607 if (!error) 608 l->l_sigstk = *nss; 609 } 610 611 mutex_exit(p->p_lock); 612 613 return (error); 614 } 615 616 int 617 __sigtimedwait1(struct lwp *l, const struct sys___sigtimedwait_args *uap, register_t *retval, 618 copyout_t put_info, copyin_t fetch_timeout, copyout_t put_timeout) 619 { 620 /* { 621 syscallarg(const sigset_t *) set; 622 syscallarg(siginfo_t *) info; 623 syscallarg(struct timespec *) timeout; 624 } */ 625 struct proc *p = l->l_proc; 626 int error, signum; 627 int timo = 0; 628 struct timespec ts, tsstart, tsnow; 629 ksiginfo_t *ksi; 630 631 memset(&tsstart, 0, sizeof tsstart); /* XXX gcc */ 632 633 /* 634 * Calculate timeout, if it was specified. 635 */ 636 if (SCARG(uap, timeout)) { 637 uint64_t ms; 638 639 if ((error = (*fetch_timeout)(SCARG(uap, timeout), &ts, sizeof(ts)))) 640 return (error); 641 642 ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000); 643 timo = mstohz(ms); 644 if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0) 645 timo = 1; 646 if (timo <= 0) 647 return (EAGAIN); 648 649 /* 650 * Remember current uptime, it would be used in 651 * ECANCELED/ERESTART case. 652 */ 653 getnanouptime(&tsstart); 654 } 655 656 error = copyin(SCARG(uap, set), &l->l_sigwaitset, 657 sizeof(l->l_sigwaitset)); 658 if (error != 0) 659 return (error); 660 661 /* 662 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 663 * SA_CANTMASK signals in waitset, we do this only for the below 664 * siglist check. 665 */ 666 sigminusset(&sigcantmask, &l->l_sigwaitset); 667 668 /* 669 * Allocate a ksi up front. We can't sleep with the mutex held. 670 */ 671 ksi = ksiginfo_alloc(p, NULL, PR_WAITOK); 672 if (ksi == NULL) 673 return (ENOMEM); 674 675 mutex_enter(p->p_lock); 676 677 /* 678 * SA processes can have no more than 1 sigwaiter. 679 */ 680 if ((p->p_sflag & PS_SA) != 0 && !LIST_EMPTY(&p->p_sigwaiters)) { 681 mutex_exit(p->p_lock); 682 error = EINVAL; 683 goto out; 684 } 685 686 if ((signum = sigget(&p->p_sigpend, ksi, 0, &l->l_sigwaitset)) == 0) 687 signum = sigget(&l->l_sigpend, ksi, 0, &l->l_sigwaitset); 688 689 if (signum != 0) { 690 /* 691 * We found a pending signal - copy it out to the user. 692 */ 693 mutex_exit(p->p_lock); 694 goto out; 695 } 696 697 /* 698 * Set up the sigwait list. 699 */ 700 l->l_sigwaited = ksi; 701 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 702 703 /* 704 * Wait for signal to arrive. We can either be woken up or time out. 705 */ 706 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 707 708 /* 709 * Need to find out if we woke as a result of lwp_wakeup() or a 710 * signal outside our wait set. 711 */ 712 if (l->l_sigwaited != NULL) { 713 if (error == EINTR) { 714 /* wakeup via _lwp_wakeup() */ 715 error = ECANCELED; 716 } else if (!error) { 717 /* spurious wakeup - arrange for syscall restart */ 718 error = ERESTART; 719 } 720 l->l_sigwaited = NULL; 721 LIST_REMOVE(l, l_sigwaiter); 722 } 723 724 mutex_exit(p->p_lock); 725 726 /* 727 * If the sleep was interrupted (either by signal or wakeup), update 728 * the timeout and copyout new value back. It would be used when 729 * the syscall would be restarted or called again. 730 */ 731 if (timo && (error == ERESTART || error == ECANCELED)) { 732 getnanouptime(&tsnow); 733 734 /* compute how much time has passed since start */ 735 timespecsub(&tsnow, &tsstart, &tsnow); 736 /* substract passed time from timeout */ 737 timespecsub(&ts, &tsnow, &ts); 738 739 if (ts.tv_sec < 0) 740 error = EAGAIN; 741 else { 742 /* copy updated timeout to userland */ 743 error = (*put_timeout)(&ts, SCARG(uap, timeout), 744 sizeof(ts)); 745 } 746 } 747 748 /* 749 * If a signal from the wait set arrived, copy it to userland. 750 * Copy only the used part of siginfo, the padding part is 751 * left unchanged (userland is not supposed to touch it anyway). 752 */ 753 out: 754 if (error == 0) 755 error = (*put_info)(&ksi->ksi_info, SCARG(uap, info), 756 sizeof(ksi->ksi_info)); 757 758 ksiginfo_free(ksi); 759 760 return error; 761 } 762
Indexes created Mon Sep 29 21:09:56 GMT 2025