sys_sig.c revision 1.46
1 /* $NetBSD: sys_sig.c,v 1.46 2016/08/04 06:43:43 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 1.46 2016/08/04 06:43:43 christos Exp $"); 70 71 #include "opt_dtrace.h" 72 73 #include <sys/param.h> 74 #include <sys/kernel.h> 75 #include <sys/signalvar.h> 76 #include <sys/proc.h> 77 #include <sys/pool.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 #include <sys/sdt.h> 84 85 SDT_PROVIDER_DECLARE(proc); 86 SDT_PROBE_DEFINE2(proc, kernel, , signal__clear, 87 "int", /* signal */ 88 "ksiginfo_t *"); /* signal-info */ 89 90 int 91 sys___sigaction_sigtramp(struct lwp *l, 92 const struct sys___sigaction_sigtramp_args *uap, register_t *retval) 93 { 94 /* { 95 syscallarg(int) signum; 96 syscallarg(const struct sigaction *) nsa; 97 syscallarg(struct sigaction *) osa; 98 syscallarg(void *) tramp; 99 syscallarg(int) vers; 100 } */ 101 struct sigaction nsa, osa; 102 int error; 103 104 if (SCARG(uap, nsa)) { 105 error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); 106 if (error) 107 return (error); 108 } 109 error = sigaction1(l, SCARG(uap, signum), 110 SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, 111 SCARG(uap, tramp), SCARG(uap, vers)); 112 if (error) 113 return (error); 114 if (SCARG(uap, osa)) { 115 error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); 116 if (error) 117 return (error); 118 } 119 return 0; 120 } 121 122 /* 123 * Manipulate signal mask. Note that we receive new mask, not pointer, and 124 * return old mask as return value; the library stub does the rest. 125 */ 126 int 127 sys___sigprocmask14(struct lwp *l, const struct sys___sigprocmask14_args *uap, 128 register_t *retval) 129 { 130 /* { 131 syscallarg(int) how; 132 syscallarg(const sigset_t *) set; 133 syscallarg(sigset_t *) oset; 134 } */ 135 struct proc *p = l->l_proc; 136 sigset_t nss, oss; 137 int error; 138 139 if (SCARG(uap, set)) { 140 error = copyin(SCARG(uap, set), &nss, sizeof(nss)); 141 if (error) 142 return error; 143 } 144 mutex_enter(p->p_lock); 145 error = sigprocmask1(l, SCARG(uap, how), 146 SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); 147 mutex_exit(p->p_lock); 148 if (error) 149 return error; 150 if (SCARG(uap, oset)) { 151 error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); 152 if (error) 153 return error; 154 } 155 return 0; 156 } 157 158 int 159 sys___sigpending14(struct lwp *l, const struct sys___sigpending14_args *uap, 160 register_t *retval) 161 { 162 /* { 163 syscallarg(sigset_t *) set; 164 } */ 165 sigset_t ss; 166 167 sigpending1(l, &ss); 168 return copyout(&ss, SCARG(uap, set), sizeof(ss)); 169 } 170 171 /* 172 * Suspend process until signal, providing mask to be set in the meantime. 173 * Note nonstandard calling convention: libc stub passes mask, not pointer, 174 * to save a copyin. 175 */ 176 int 177 sys___sigsuspend14(struct lwp *l, const struct sys___sigsuspend14_args *uap, 178 register_t *retval) 179 { 180 /* { 181 syscallarg(const sigset_t *) set; 182 } */ 183 sigset_t ss; 184 int error; 185 186 if (SCARG(uap, set)) { 187 error = copyin(SCARG(uap, set), &ss, sizeof(ss)); 188 if (error) 189 return error; 190 } 191 return sigsuspend1(l, SCARG(uap, set) ? &ss : 0); 192 } 193 194 int 195 sys___sigaltstack14(struct lwp *l, const struct sys___sigaltstack14_args *uap, 196 register_t *retval) 197 { 198 /* { 199 syscallarg(const struct sigaltstack *) nss; 200 syscallarg(struct sigaltstack *) oss; 201 } */ 202 struct sigaltstack nss, oss; 203 int error; 204 205 if (SCARG(uap, nss)) { 206 error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); 207 if (error) 208 return error; 209 } 210 error = sigaltstack1(l, 211 SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); 212 if (error) 213 return error; 214 if (SCARG(uap, oss)) { 215 error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); 216 if (error) 217 return error; 218 } 219 return 0; 220 } 221 222 int 223 kill1(struct lwp *l, pid_t pid, ksiginfo_t *ksi, register_t *retval) 224 { 225 int error; 226 struct proc *p; 227 228 if ((u_int)ksi->ksi_signo >= NSIG) 229 return EINVAL; 230 231 if (pid != l->l_proc->p_pid) { 232 if (ksi->ksi_pid != l->l_proc->p_pid) 233 return EPERM; 234 235 if (ksi->ksi_uid != kauth_cred_geteuid(l->l_cred)) 236 return EPERM; 237 238 switch (ksi->ksi_code) { 239 case SI_USER: 240 case SI_QUEUE: 241 break; 242 default: 243 return EPERM; 244 } 245 } 246 247 if (pid > 0) { 248 /* kill single process */ 249 mutex_enter(proc_lock); 250 p = proc_find_raw(pid); 251 if (p == NULL || (p->p_stat != SACTIVE && p->p_stat != SSTOP)) { 252 mutex_exit(proc_lock); 253 /* IEEE Std 1003.1-2001: return success for zombies */ 254 return p ? 0 : ESRCH; 255 } 256 mutex_enter(p->p_lock); 257 error = kauth_authorize_process(l->l_cred, 258 KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(ksi->ksi_signo), 259 NULL, NULL); 260 if (!error && ksi->ksi_signo) { 261 error = kpsignal2(p, ksi); 262 } 263 mutex_exit(p->p_lock); 264 mutex_exit(proc_lock); 265 return error; 266 } 267 268 switch (pid) { 269 case -1: /* broadcast signal */ 270 return killpg1(l, ksi, 0, 1); 271 case 0: /* signal own process group */ 272 return killpg1(l, ksi, 0, 0); 273 default: /* negative explicit process group */ 274 return killpg1(l, ksi, -pid, 0); 275 } 276 /* NOTREACHED */ 277 } 278 279 int 280 sys_sigqueueinfo(struct lwp *l, const struct sys_sigqueueinfo_args *uap, 281 register_t *retval) 282 { 283 /* { 284 syscallarg(pid_t int) pid; 285 syscallarg(const siginfo_t *) info; 286 } */ 287 ksiginfo_t ksi; 288 int error; 289 290 KSI_INIT(&ksi); 291 292 if ((error = copyin(&SCARG(uap, info)->_info, &ksi.ksi_info, 293 sizeof(ksi.ksi_info))) != 0) 294 return error; 295 296 return kill1(l, SCARG(uap, pid), &ksi, retval); 297 } 298 299 int 300 sys_kill(struct lwp *l, const struct sys_kill_args *uap, register_t *retval) 301 { 302 /* { 303 syscallarg(pid_t) pid; 304 syscallarg(int) signum; 305 } */ 306 ksiginfo_t ksi; 307 308 KSI_INIT(&ksi); 309 310 ksi.ksi_signo = SCARG(uap, signum); 311 ksi.ksi_code = SI_USER; 312 ksi.ksi_pid = l->l_proc->p_pid; 313 ksi.ksi_uid = kauth_cred_geteuid(l->l_cred); 314 315 return kill1(l, SCARG(uap, pid), &ksi, retval); 316 } 317 318 int 319 sys_getcontext(struct lwp *l, const struct sys_getcontext_args *uap, 320 register_t *retval) 321 { 322 /* { 323 syscallarg(struct __ucontext *) ucp; 324 } */ 325 struct proc *p = l->l_proc; 326 ucontext_t uc; 327 328 memset(&uc, 0, sizeof(uc)); 329 330 mutex_enter(p->p_lock); 331 getucontext(l, &uc); 332 mutex_exit(p->p_lock); 333 334 return copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp))); 335 } 336 337 int 338 sys_setcontext(struct lwp *l, const struct sys_setcontext_args *uap, 339 register_t *retval) 340 { 341 /* { 342 syscallarg(const ucontext_t *) ucp; 343 } */ 344 struct proc *p = l->l_proc; 345 ucontext_t uc; 346 int error; 347 348 error = copyin(SCARG(uap, ucp), &uc, sizeof (uc)); 349 if (error) 350 return error; 351 if ((uc.uc_flags & _UC_CPU) == 0) 352 return EINVAL; 353 mutex_enter(p->p_lock); 354 error = setucontext(l, &uc); 355 mutex_exit(p->p_lock); 356 if (error) 357 return error; 358 359 return EJUSTRETURN; 360 } 361 362 /* 363 * sigtimedwait(2) system call, used also for implementation 364 * of sigwaitinfo() and sigwait(). 365 * 366 * This only handles single LWP in signal wait. libpthread provides 367 * its own sigtimedwait() wrapper to DTRT WRT individual threads. 368 */ 369 int 370 sys_____sigtimedwait50(struct lwp *l, 371 const struct sys_____sigtimedwait50_args *uap, register_t *retval) 372 { 373 374 return sigtimedwait1(l, uap, retval, copyin, copyout, copyin, copyout); 375 } 376 377 int 378 sigaction1(struct lwp *l, int signum, const struct sigaction *nsa, 379 struct sigaction *osa, const void *tramp, int vers) 380 { 381 struct proc *p; 382 struct sigacts *ps; 383 sigset_t tset; 384 int prop, error; 385 ksiginfoq_t kq; 386 static bool v0v1valid; 387 388 if (signum <= 0 || signum >= NSIG) 389 return EINVAL; 390 391 p = l->l_proc; 392 error = 0; 393 ksiginfo_queue_init(&kq); 394 395 /* 396 * Trampoline ABI version 0 is reserved for the legacy kernel 397 * provided on-stack trampoline. Conversely, if we are using a 398 * non-0 ABI version, we must have a trampoline. Only validate the 399 * vers if a new sigaction was supplied and there was an actual 400 * handler specified (not SIG_IGN or SIG_DFL), which don't require 401 * a trampoline. Emulations use legacy kernel trampolines with 402 * version 0, alternatively check for that too. 403 * 404 * If version < 2, we try to autoload the compat module. Note 405 * that we interlock with the unload check in compat_modcmd() 406 * using kernconfig_lock. If the autoload fails, we don't try it 407 * again for this process. 408 */ 409 if (nsa != NULL && nsa->sa_handler != SIG_IGN 410 && nsa->sa_handler != SIG_DFL) { 411 if (__predict_false(vers < 2)) { 412 if (p->p_flag & PK_32) 413 v0v1valid = true; 414 else if ((p->p_lflag & PL_SIGCOMPAT) == 0) { 415 kernconfig_lock(); 416 if (sendsig_sigcontext_vec == NULL) { 417 (void)module_autoload("compat", 418 MODULE_CLASS_ANY); 419 } 420 if (sendsig_sigcontext_vec != NULL) { 421 /* 422 * We need to remember if the 423 * sigcontext method may be useable, 424 * because libc may use it even 425 * if siginfo is available. 426 */ 427 v0v1valid = true; 428 } 429 mutex_enter(proc_lock); 430 /* 431 * Prevent unload of compat module while 432 * this process remains. 433 */ 434 p->p_lflag |= PL_SIGCOMPAT; 435 mutex_exit(proc_lock); 436 kernconfig_unlock(); 437 } 438 } 439 440 switch (vers) { 441 case 0: 442 /* sigcontext, kernel supplied trampoline. */ 443 if (tramp != NULL || !v0v1valid) { 444 return EINVAL; 445 } 446 break; 447 case 1: 448 /* sigcontext, user supplied trampoline. */ 449 if (tramp == NULL || !v0v1valid) { 450 return EINVAL; 451 } 452 break; 453 case 2: 454 case 3: 455 /* siginfo, user supplied trampoline. */ 456 if (tramp == NULL) { 457 return EINVAL; 458 } 459 break; 460 default: 461 return EINVAL; 462 } 463 } 464 465 mutex_enter(p->p_lock); 466 467 ps = p->p_sigacts; 468 if (osa) 469 *osa = SIGACTION_PS(ps, signum); 470 if (!nsa) 471 goto out; 472 473 prop = sigprop[signum]; 474 if ((nsa->sa_flags & ~SA_ALLBITS) || (prop & SA_CANTMASK)) { 475 error = EINVAL; 476 goto out; 477 } 478 479 SIGACTION_PS(ps, signum) = *nsa; 480 ps->sa_sigdesc[signum].sd_tramp = tramp; 481 ps->sa_sigdesc[signum].sd_vers = vers; 482 sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); 483 484 if ((prop & SA_NORESET) != 0) 485 SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; 486 487 if (signum == SIGCHLD) { 488 if (nsa->sa_flags & SA_NOCLDSTOP) 489 p->p_sflag |= PS_NOCLDSTOP; 490 else 491 p->p_sflag &= ~PS_NOCLDSTOP; 492 if (nsa->sa_flags & SA_NOCLDWAIT) { 493 /* 494 * Paranoia: since SA_NOCLDWAIT is implemented by 495 * reparenting the dying child to PID 1 (and trust 496 * it to reap the zombie), PID 1 itself is forbidden 497 * to set SA_NOCLDWAIT. 498 */ 499 if (p->p_pid == 1) 500 p->p_flag &= ~PK_NOCLDWAIT; 501 else 502 p->p_flag |= PK_NOCLDWAIT; 503 } else 504 p->p_flag &= ~PK_NOCLDWAIT; 505 506 if (nsa->sa_handler == SIG_IGN) { 507 /* 508 * Paranoia: same as above. 509 */ 510 if (p->p_pid == 1) 511 p->p_flag &= ~PK_CLDSIGIGN; 512 else 513 p->p_flag |= PK_CLDSIGIGN; 514 } else 515 p->p_flag &= ~PK_CLDSIGIGN; 516 } 517 518 if ((nsa->sa_flags & SA_NODEFER) == 0) 519 sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); 520 else 521 sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); 522 523 /* 524 * Set bit in p_sigctx.ps_sigignore for signals that are set to 525 * SIG_IGN, and for signals set to SIG_DFL where the default is to 526 * ignore. However, don't put SIGCONT in p_sigctx.ps_sigignore, as 527 * we have to restart the process. 528 */ 529 if (nsa->sa_handler == SIG_IGN || 530 (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { 531 /* Never to be seen again. */ 532 sigemptyset(&tset); 533 sigaddset(&tset, signum); 534 sigclearall(p, &tset, &kq); 535 if (signum != SIGCONT) { 536 /* Easier in psignal */ 537 sigaddset(&p->p_sigctx.ps_sigignore, signum); 538 } 539 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 540 } else { 541 sigdelset(&p->p_sigctx.ps_sigignore, signum); 542 if (nsa->sa_handler == SIG_DFL) 543 sigdelset(&p->p_sigctx.ps_sigcatch, signum); 544 else 545 sigaddset(&p->p_sigctx.ps_sigcatch, signum); 546 } 547 548 /* 549 * Previously held signals may now have become visible. Ensure that 550 * we check for them before returning to userspace. 551 */ 552 if (sigispending(l, 0)) { 553 lwp_lock(l); 554 l->l_flag |= LW_PENDSIG; 555 lwp_unlock(l); 556 } 557 out: 558 mutex_exit(p->p_lock); 559 ksiginfo_queue_drain(&kq); 560 561 return error; 562 } 563 564 int 565 sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss) 566 { 567 sigset_t *mask = &l->l_sigmask; 568 bool more; 569 570 KASSERT(mutex_owned(l->l_proc->p_lock)); 571 572 if (oss) { 573 *oss = *mask; 574 } 575 576 if (nss == NULL) { 577 return 0; 578 } 579 580 switch (how) { 581 case SIG_BLOCK: 582 sigplusset(nss, mask); 583 more = false; 584 break; 585 case SIG_UNBLOCK: 586 sigminusset(nss, mask); 587 more = true; 588 break; 589 case SIG_SETMASK: 590 *mask = *nss; 591 more = true; 592 break; 593 default: 594 return EINVAL; 595 } 596 sigminusset(&sigcantmask, mask); 597 if (more && sigispending(l, 0)) { 598 /* 599 * Check for pending signals on return to user. 600 */ 601 lwp_lock(l); 602 l->l_flag |= LW_PENDSIG; 603 lwp_unlock(l); 604 } 605 return 0; 606 } 607 608 void 609 sigpending1(struct lwp *l, sigset_t *ss) 610 { 611 struct proc *p = l->l_proc; 612 613 mutex_enter(p->p_lock); 614 *ss = l->l_sigpend.sp_set; 615 sigplusset(&p->p_sigpend.sp_set, ss); 616 mutex_exit(p->p_lock); 617 } 618 619 void 620 sigsuspendsetup(struct lwp *l, const sigset_t *ss) 621 { 622 struct proc *p = l->l_proc; 623 624 /* 625 * When returning from sigsuspend/pselect/pollts, we want 626 * the old mask to be restored after the 627 * signal handler has finished. Thus, we 628 * save it here and mark the sigctx structure 629 * to indicate this. 630 */ 631 mutex_enter(p->p_lock); 632 l->l_sigrestore = 1; 633 l->l_sigoldmask = l->l_sigmask; 634 l->l_sigmask = *ss; 635 sigminusset(&sigcantmask, &l->l_sigmask); 636 637 /* Check for pending signals when sleeping. */ 638 if (sigispending(l, 0)) { 639 lwp_lock(l); 640 l->l_flag |= LW_PENDSIG; 641 lwp_unlock(l); 642 } 643 mutex_exit(p->p_lock); 644 } 645 646 void 647 sigsuspendteardown(struct lwp *l) 648 { 649 struct proc *p = l->l_proc; 650 651 mutex_enter(p->p_lock); 652 /* Check for pending signals when sleeping. */ 653 if (l->l_sigrestore) { 654 if (sigispending(l, 0)) { 655 lwp_lock(l); 656 l->l_flag |= LW_PENDSIG; 657 lwp_unlock(l); 658 } else { 659 l->l_sigrestore = 0; 660 l->l_sigmask = l->l_sigoldmask; 661 } 662 } 663 mutex_exit(p->p_lock); 664 } 665 666 int 667 sigsuspend1(struct lwp *l, const sigset_t *ss) 668 { 669 670 if (ss) 671 sigsuspendsetup(l, ss); 672 673 while (kpause("pause", true, 0, NULL) == 0) 674 ; 675 676 /* always return EINTR rather than ERESTART... */ 677 return EINTR; 678 } 679 680 int 681 sigaltstack1(struct lwp *l, const struct sigaltstack *nss, 682 struct sigaltstack *oss) 683 { 684 struct proc *p = l->l_proc; 685 int error = 0; 686 687 mutex_enter(p->p_lock); 688 689 if (oss) 690 *oss = l->l_sigstk; 691 692 if (nss) { 693 if (nss->ss_flags & ~SS_ALLBITS) 694 error = EINVAL; 695 else if (nss->ss_flags & SS_DISABLE) { 696 if (l->l_sigstk.ss_flags & SS_ONSTACK) 697 error = EINVAL; 698 } else if (nss->ss_size < MINSIGSTKSZ) 699 error = ENOMEM; 700 701 if (!error) 702 l->l_sigstk = *nss; 703 } 704 705 mutex_exit(p->p_lock); 706 707 return error; 708 } 709 710 int 711 sigtimedwait1(struct lwp *l, const struct sys_____sigtimedwait50_args *uap, 712 register_t *retval, copyin_t fetchss, copyout_t storeinf, copyin_t fetchts, 713 copyout_t storets) 714 { 715 /* { 716 syscallarg(const sigset_t *) set; 717 syscallarg(siginfo_t *) info; 718 syscallarg(struct timespec *) timeout; 719 } */ 720 struct proc *p = l->l_proc; 721 int error, signum, timo; 722 struct timespec ts, tsstart, tsnow; 723 ksiginfo_t ksi; 724 725 /* 726 * Calculate timeout, if it was specified. 727 * 728 * NULL pointer means an infinite timeout. 729 * {.tv_sec = 0, .tv_nsec = 0} means do not block. 730 */ 731 if (SCARG(uap, timeout)) { 732 error = (*fetchts)(SCARG(uap, timeout), &ts, sizeof(ts)); 733 if (error) 734 return error; 735 736 if ((error = itimespecfix(&ts)) != 0) 737 return error; 738 739 timo = tstohz(&ts); 740 if (timo == 0) { 741 if (ts.tv_sec == 0 && ts.tv_nsec == 0) 742 timo = -1; /* do not block */ 743 else 744 timo = 1; /* the shortest possible timeout */ 745 } 746 747 /* 748 * Remember current uptime, it would be used in 749 * ECANCELED/ERESTART case. 750 */ 751 getnanouptime(&tsstart); 752 } else { 753 memset(&tsstart, 0, sizeof(tsstart)); /* XXXgcc */ 754 timo = 0; /* infinite timeout */ 755 } 756 757 error = (*fetchss)(SCARG(uap, set), &l->l_sigwaitset, 758 sizeof(l->l_sigwaitset)); 759 if (error) 760 return error; 761 762 /* 763 * Silently ignore SA_CANTMASK signals. psignal1() would ignore 764 * SA_CANTMASK signals in waitset, we do this only for the below 765 * siglist check. 766 */ 767 sigminusset(&sigcantmask, &l->l_sigwaitset); 768 769 mutex_enter(p->p_lock); 770 771 /* Check for pending signals in the process, if no - then in LWP. */ 772 if ((signum = sigget(&p->p_sigpend, &ksi, 0, &l->l_sigwaitset)) == 0) 773 signum = sigget(&l->l_sigpend, &ksi, 0, &l->l_sigwaitset); 774 775 if (signum != 0) { 776 /* If found a pending signal, just copy it out to the user. */ 777 mutex_exit(p->p_lock); 778 goto out; 779 } 780 781 if (timo < 0) { 782 /* If not allowed to block, return an error */ 783 mutex_exit(p->p_lock); 784 return EAGAIN; 785 } 786 787 /* 788 * Set up the sigwait list and wait for signal to arrive. 789 * We can either be woken up or time out. 790 */ 791 l->l_sigwaited = &ksi; 792 LIST_INSERT_HEAD(&p->p_sigwaiters, l, l_sigwaiter); 793 error = cv_timedwait_sig(&l->l_sigcv, p->p_lock, timo); 794 795 /* 796 * Need to find out if we woke as a result of _lwp_wakeup() or a 797 * signal outside our wait set. 798 */ 799 if (l->l_sigwaited != NULL) { 800 if (error == EINTR) { 801 /* Wakeup via _lwp_wakeup(). */ 802 error = ECANCELED; 803 } else if (!error) { 804 /* Spurious wakeup - arrange for syscall restart. */ 805 error = ERESTART; 806 } 807 l->l_sigwaited = NULL; 808 LIST_REMOVE(l, l_sigwaiter); 809 } 810 mutex_exit(p->p_lock); 811 812 /* 813 * If the sleep was interrupted (either by signal or wakeup), update 814 * the timeout and copyout new value back. It would be used when 815 * the syscall would be restarted or called again. 816 */ 817 if (timo && (error == ERESTART || error == ECANCELED)) { 818 getnanouptime(&tsnow); 819 820 /* Compute how much time has passed since start. */ 821 timespecsub(&tsnow, &tsstart, &tsnow); 822 823 /* Substract passed time from timeout. */ 824 timespecsub(&ts, &tsnow, &ts); 825 826 if (ts.tv_sec < 0) 827 error = EAGAIN; 828 else { 829 /* Copy updated timeout to userland. */ 830 error = (*storets)(&ts, SCARG(uap, timeout), 831 sizeof(ts)); 832 } 833 } 834 out: 835 /* 836 * If a signal from the wait set arrived, copy it to userland. 837 * Copy only the used part of siginfo, the padding part is 838 * left unchanged (userland is not supposed to touch it anyway). 839 */ 840 if (error == 0 && SCARG(uap, info)) { 841 error = (*storeinf)(&ksi.ksi_info, SCARG(uap, info), 842 sizeof(ksi.ksi_info)); 843 } 844 if (error == 0) { 845 *retval = ksi.ksi_info._signo; 846 SDT_PROBE(proc, kernel, , signal__clear, *retval, 847 &ksi, 0, 0, 0); 848 } 849 return error; 850 } 851
Indexes created Mon Sep 22 10:09:38 GMT 2025