1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 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 University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 * $DragonFly: src/sys/kern/kern_sig.c,v 1.77 2007/04/29 18:25:34 dillon Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/sysproto.h> 49 #include <sys/signalvar.h> 50 #include <sys/signal2.h> 51 #include <sys/resourcevar.h> 52 #include <sys/vnode.h> 53 #include <sys/event.h> 54 #include <sys/proc.h> 55 #include <sys/nlookup.h> 56 #include <sys/pioctl.h> 57 #include <sys/systm.h> 58 #include <sys/acct.h> 59 #include <sys/fcntl.h> 60 #include <sys/lock.h> 61 #include <sys/wait.h> 62 #include <sys/ktrace.h> 63 #include <sys/syslog.h> 64 #include <sys/stat.h> 65 #include <sys/sysent.h> 66 #include <sys/sysctl.h> 67 #include <sys/malloc.h> 68 #include <sys/interrupt.h> 69 #include <sys/unistd.h> 70 #include <sys/kern_syscall.h> 71 #include <sys/vkernel.h> 72 #include <sys/thread2.h> 73 74 #include <machine/cpu.h> 75 #include <machine/smp.h> 76 77 static int coredump(struct lwp *, int); 78 static char *expand_name(const char *, uid_t, pid_t); 79 static int dokillpg(int sig, int pgid, int all); 80 static int sig_ffs(sigset_t *set); 81 static int sigprop(int sig); 82 #ifdef SMP 83 static void signotify_remote(void *arg); 84 #endif 85 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 86 struct timespec *timeout); 87 88 static int filt_sigattach(struct knote *kn); 89 static void filt_sigdetach(struct knote *kn); 90 static int filt_signal(struct knote *kn, long hint); 91 92 struct filterops sig_filtops = 93 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 94 95 static int kern_logsigexit = 1; 96 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 97 &kern_logsigexit, 0, 98 "Log processes quitting on abnormal signals to syslog(3)"); 99 100 /* 101 * Can process p, with pcred pc, send the signal sig to process q? 102 */ 103 #define CANSIGNAL(q, sig) \ 104 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 105 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 106 107 /* 108 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 109 */ 110 #define CANSIGIO(ruid, uc, q) \ 111 ((uc)->cr_uid == 0 || \ 112 (ruid) == (q)->p_ucred->cr_ruid || \ 113 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 114 (ruid) == (q)->p_ucred->cr_uid || \ 115 (uc)->cr_uid == (q)->p_ucred->cr_uid) 116 117 int sugid_coredump; 118 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 119 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 120 121 static int do_coredump = 1; 122 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 123 &do_coredump, 0, "Enable/Disable coredumps"); 124 125 /* 126 * Signal properties and actions. 127 * The array below categorizes the signals and their default actions 128 * according to the following properties: 129 */ 130 #define SA_KILL 0x01 /* terminates process by default */ 131 #define SA_CORE 0x02 /* ditto and coredumps */ 132 #define SA_STOP 0x04 /* suspend process */ 133 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 134 #define SA_IGNORE 0x10 /* ignore by default */ 135 #define SA_CONT 0x20 /* continue if suspended */ 136 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 137 #define SA_CKPT 0x80 /* checkpoint process */ 138 139 140 static int sigproptbl[NSIG] = { 141 SA_KILL, /* SIGHUP */ 142 SA_KILL, /* SIGINT */ 143 SA_KILL|SA_CORE, /* SIGQUIT */ 144 SA_KILL|SA_CORE, /* SIGILL */ 145 SA_KILL|SA_CORE, /* SIGTRAP */ 146 SA_KILL|SA_CORE, /* SIGABRT */ 147 SA_KILL|SA_CORE, /* SIGEMT */ 148 SA_KILL|SA_CORE, /* SIGFPE */ 149 SA_KILL, /* SIGKILL */ 150 SA_KILL|SA_CORE, /* SIGBUS */ 151 SA_KILL|SA_CORE, /* SIGSEGV */ 152 SA_KILL|SA_CORE, /* SIGSYS */ 153 SA_KILL, /* SIGPIPE */ 154 SA_KILL, /* SIGALRM */ 155 SA_KILL, /* SIGTERM */ 156 SA_IGNORE, /* SIGURG */ 157 SA_STOP, /* SIGSTOP */ 158 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 159 SA_IGNORE|SA_CONT, /* SIGCONT */ 160 SA_IGNORE, /* SIGCHLD */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 163 SA_IGNORE, /* SIGIO */ 164 SA_KILL, /* SIGXCPU */ 165 SA_KILL, /* SIGXFSZ */ 166 SA_KILL, /* SIGVTALRM */ 167 SA_KILL, /* SIGPROF */ 168 SA_IGNORE, /* SIGWINCH */ 169 SA_IGNORE, /* SIGINFO */ 170 SA_KILL, /* SIGUSR1 */ 171 SA_KILL, /* SIGUSR2 */ 172 SA_IGNORE, /* SIGTHR */ 173 SA_CKPT, /* SIGCKPT */ 174 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 206 }; 207 208 static __inline int 209 sigprop(int sig) 210 { 211 212 if (sig > 0 && sig < NSIG) 213 return (sigproptbl[_SIG_IDX(sig)]); 214 return (0); 215 } 216 217 static __inline int 218 sig_ffs(sigset_t *set) 219 { 220 int i; 221 222 for (i = 0; i < _SIG_WORDS; i++) 223 if (set->__bits[i]) 224 return (ffs(set->__bits[i]) + (i * 32)); 225 return (0); 226 } 227 228 int 229 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 230 { 231 struct thread *td = curthread; 232 struct proc *p = td->td_proc; 233 struct lwp *lp; 234 struct sigacts *ps = p->p_sigacts; 235 236 if (sig <= 0 || sig > _SIG_MAXSIG) 237 return (EINVAL); 238 239 if (oact) { 240 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 241 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 242 oact->sa_flags = 0; 243 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 244 oact->sa_flags |= SA_ONSTACK; 245 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 246 oact->sa_flags |= SA_RESTART; 247 if (SIGISMEMBER(ps->ps_sigreset, sig)) 248 oact->sa_flags |= SA_RESETHAND; 249 if (SIGISMEMBER(ps->ps_signodefer, sig)) 250 oact->sa_flags |= SA_NODEFER; 251 if (SIGISMEMBER(ps->ps_siginfo, sig)) 252 oact->sa_flags |= SA_SIGINFO; 253 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 254 oact->sa_flags |= SA_MAILBOX; 255 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 256 oact->sa_flags |= SA_NOCLDSTOP; 257 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 258 oact->sa_flags |= SA_NOCLDWAIT; 259 } 260 if (act) { 261 /* 262 * Check for invalid requests. KILL and STOP cannot be 263 * caught. 264 */ 265 if (sig == SIGKILL || sig == SIGSTOP) { 266 if (act->sa_handler != SIG_DFL) 267 return (EINVAL); 268 #if 0 269 /* (not needed, SIG_DFL forces action to occur) */ 270 if (act->sa_flags & SA_MAILBOX) 271 return (EINVAL); 272 #endif 273 } 274 275 /* 276 * Change setting atomically. 277 */ 278 crit_enter(); 279 280 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 281 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 282 if (act->sa_flags & SA_SIGINFO) { 283 ps->ps_sigact[_SIG_IDX(sig)] = 284 (__sighandler_t *)act->sa_sigaction; 285 SIGADDSET(ps->ps_siginfo, sig); 286 } else { 287 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 288 SIGDELSET(ps->ps_siginfo, sig); 289 } 290 if (!(act->sa_flags & SA_RESTART)) 291 SIGADDSET(ps->ps_sigintr, sig); 292 else 293 SIGDELSET(ps->ps_sigintr, sig); 294 if (act->sa_flags & SA_ONSTACK) 295 SIGADDSET(ps->ps_sigonstack, sig); 296 else 297 SIGDELSET(ps->ps_sigonstack, sig); 298 if (act->sa_flags & SA_RESETHAND) 299 SIGADDSET(ps->ps_sigreset, sig); 300 else 301 SIGDELSET(ps->ps_sigreset, sig); 302 if (act->sa_flags & SA_NODEFER) 303 SIGADDSET(ps->ps_signodefer, sig); 304 else 305 SIGDELSET(ps->ps_signodefer, sig); 306 if (act->sa_flags & SA_MAILBOX) 307 SIGADDSET(ps->ps_sigmailbox, sig); 308 else 309 SIGDELSET(ps->ps_sigmailbox, sig); 310 if (sig == SIGCHLD) { 311 if (act->sa_flags & SA_NOCLDSTOP) 312 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 313 else 314 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 315 if (act->sa_flags & SA_NOCLDWAIT) { 316 /* 317 * Paranoia: since SA_NOCLDWAIT is implemented 318 * by reparenting the dying child to PID 1 (and 319 * trust it to reap the zombie), PID 1 itself 320 * is forbidden to set SA_NOCLDWAIT. 321 */ 322 if (p->p_pid == 1) 323 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 324 else 325 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 326 } else { 327 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 328 } 329 } 330 /* 331 * Set bit in p_sigignore for signals that are set to SIG_IGN, 332 * and for signals set to SIG_DFL where the default is to 333 * ignore. However, don't put SIGCONT in p_sigignore, as we 334 * have to restart the process. 335 */ 336 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 337 (sigprop(sig) & SA_IGNORE && 338 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 339 /* never to be seen again */ 340 SIGDELSET(p->p_siglist, sig); 341 /* 342 * Remove the signal also from the thread lists. 343 */ 344 FOREACH_LWP_IN_PROC(lp, p) { 345 SIGDELSET(lp->lwp_siglist, sig); 346 } 347 if (sig != SIGCONT) 348 /* easier in ksignal */ 349 SIGADDSET(p->p_sigignore, sig); 350 SIGDELSET(p->p_sigcatch, sig); 351 } else { 352 SIGDELSET(p->p_sigignore, sig); 353 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 354 SIGDELSET(p->p_sigcatch, sig); 355 else 356 SIGADDSET(p->p_sigcatch, sig); 357 } 358 359 crit_exit(); 360 } 361 return (0); 362 } 363 364 int 365 sys_sigaction(struct sigaction_args *uap) 366 { 367 struct sigaction act, oact; 368 struct sigaction *actp, *oactp; 369 int error; 370 371 actp = (uap->act != NULL) ? &act : NULL; 372 oactp = (uap->oact != NULL) ? &oact : NULL; 373 if (actp) { 374 error = copyin(uap->act, actp, sizeof(act)); 375 if (error) 376 return (error); 377 } 378 error = kern_sigaction(uap->sig, actp, oactp); 379 if (oactp && !error) { 380 error = copyout(oactp, uap->oact, sizeof(oact)); 381 } 382 return (error); 383 } 384 385 /* 386 * Initialize signal state for process 0; 387 * set to ignore signals that are ignored by default. 388 */ 389 void 390 siginit(struct proc *p) 391 { 392 int i; 393 394 for (i = 1; i <= NSIG; i++) 395 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 396 SIGADDSET(p->p_sigignore, i); 397 } 398 399 /* 400 * Reset signals for an exec of the specified process. 401 */ 402 void 403 execsigs(struct proc *p) 404 { 405 struct sigacts *ps = p->p_sigacts; 406 struct lwp *lp; 407 int sig; 408 409 lp = ONLY_LWP_IN_PROC(p); 410 411 /* 412 * Reset caught signals. Held signals remain held 413 * through p_sigmask (unless they were caught, 414 * and are now ignored by default). 415 */ 416 while (SIGNOTEMPTY(p->p_sigcatch)) { 417 sig = sig_ffs(&p->p_sigcatch); 418 SIGDELSET(p->p_sigcatch, sig); 419 if (sigprop(sig) & SA_IGNORE) { 420 if (sig != SIGCONT) 421 SIGADDSET(p->p_sigignore, sig); 422 SIGDELSET(p->p_siglist, sig); 423 SIGDELSET(lp->lwp_siglist, sig); 424 } 425 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 426 } 427 428 /* 429 * Reset stack state to the user stack. 430 * Clear set of signals caught on the signal stack. 431 */ 432 lp->lwp_sigstk.ss_flags = SS_DISABLE; 433 lp->lwp_sigstk.ss_size = 0; 434 lp->lwp_sigstk.ss_sp = 0; 435 lp->lwp_flag &= ~LWP_ALTSTACK; 436 /* 437 * Reset no zombies if child dies flag as Solaris does. 438 */ 439 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 440 } 441 442 /* 443 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 444 * 445 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 446 * p == curproc. 447 */ 448 int 449 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 450 { 451 struct thread *td = curthread; 452 struct lwp *lp = td->td_lwp; 453 int error; 454 455 if (oset != NULL) 456 *oset = lp->lwp_sigmask; 457 458 error = 0; 459 if (set != NULL) { 460 switch (how) { 461 case SIG_BLOCK: 462 SIG_CANTMASK(*set); 463 SIGSETOR(lp->lwp_sigmask, *set); 464 break; 465 case SIG_UNBLOCK: 466 SIGSETNAND(lp->lwp_sigmask, *set); 467 break; 468 case SIG_SETMASK: 469 SIG_CANTMASK(*set); 470 lp->lwp_sigmask = *set; 471 break; 472 default: 473 error = EINVAL; 474 break; 475 } 476 } 477 return (error); 478 } 479 480 /* 481 * sigprocmask() - MP SAFE 482 */ 483 int 484 sys_sigprocmask(struct sigprocmask_args *uap) 485 { 486 sigset_t set, oset; 487 sigset_t *setp, *osetp; 488 int error; 489 490 setp = (uap->set != NULL) ? &set : NULL; 491 osetp = (uap->oset != NULL) ? &oset : NULL; 492 if (setp) { 493 error = copyin(uap->set, setp, sizeof(set)); 494 if (error) 495 return (error); 496 } 497 error = kern_sigprocmask(uap->how, setp, osetp); 498 if (osetp && !error) { 499 error = copyout(osetp, uap->oset, sizeof(oset)); 500 } 501 return (error); 502 } 503 504 int 505 kern_sigpending(struct __sigset *set) 506 { 507 struct lwp *lp = curthread->td_lwp; 508 509 *set = lwp_sigpend(lp); 510 511 return (0); 512 } 513 514 int 515 sys_sigpending(struct sigpending_args *uap) 516 { 517 sigset_t set; 518 int error; 519 520 error = kern_sigpending(&set); 521 522 if (error == 0) 523 error = copyout(&set, uap->set, sizeof(set)); 524 return (error); 525 } 526 527 /* 528 * Suspend process until signal, providing mask to be set 529 * in the meantime. 530 */ 531 int 532 kern_sigsuspend(struct __sigset *set) 533 { 534 struct thread *td = curthread; 535 struct lwp *lp = td->td_lwp; 536 struct proc *p = td->td_proc; 537 struct sigacts *ps = p->p_sigacts; 538 539 /* 540 * When returning from sigsuspend, we want 541 * the old mask to be restored after the 542 * signal handler has finished. Thus, we 543 * save it here and mark the sigacts structure 544 * to indicate this. 545 */ 546 lp->lwp_oldsigmask = lp->lwp_sigmask; 547 lp->lwp_flag |= LWP_OLDMASK; 548 549 SIG_CANTMASK(*set); 550 lp->lwp_sigmask = *set; 551 while (tsleep(ps, PCATCH, "pause", 0) == 0) 552 /* void */; 553 /* always return EINTR rather than ERESTART... */ 554 return (EINTR); 555 } 556 557 /* 558 * Note nonstandard calling convention: libc stub passes mask, not 559 * pointer, to save a copyin. 560 */ 561 int 562 sys_sigsuspend(struct sigsuspend_args *uap) 563 { 564 sigset_t mask; 565 int error; 566 567 error = copyin(uap->sigmask, &mask, sizeof(mask)); 568 if (error) 569 return (error); 570 571 error = kern_sigsuspend(&mask); 572 573 return (error); 574 } 575 576 int 577 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 578 { 579 struct thread *td = curthread; 580 struct lwp *lp = td->td_lwp; 581 struct proc *p = td->td_proc; 582 583 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 584 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 585 586 if (oss) 587 *oss = lp->lwp_sigstk; 588 589 if (ss) { 590 if (ss->ss_flags & SS_DISABLE) { 591 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 592 return (EINVAL); 593 lp->lwp_flag &= ~LWP_ALTSTACK; 594 lp->lwp_sigstk.ss_flags = ss->ss_flags; 595 } else { 596 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 597 return (ENOMEM); 598 lp->lwp_flag |= LWP_ALTSTACK; 599 lp->lwp_sigstk = *ss; 600 } 601 } 602 603 return (0); 604 } 605 606 int 607 sys_sigaltstack(struct sigaltstack_args *uap) 608 { 609 stack_t ss, oss; 610 int error; 611 612 if (uap->ss) { 613 error = copyin(uap->ss, &ss, sizeof(ss)); 614 if (error) 615 return (error); 616 } 617 618 error = kern_sigaltstack(uap->ss ? &ss : NULL, 619 uap->oss ? &oss : NULL); 620 621 if (error == 0 && uap->oss) 622 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 623 return (error); 624 } 625 626 /* 627 * Common code for kill process group/broadcast kill. 628 * cp is calling process. 629 */ 630 struct killpg_info { 631 int nfound; 632 int sig; 633 }; 634 635 static int killpg_all_callback(struct proc *p, void *data); 636 637 static int 638 dokillpg(int sig, int pgid, int all) 639 { 640 struct killpg_info info; 641 struct proc *cp = curproc; 642 struct proc *p; 643 struct pgrp *pgrp; 644 645 info.nfound = 0; 646 info.sig = sig; 647 648 if (all) { 649 /* 650 * broadcast 651 */ 652 allproc_scan(killpg_all_callback, &info); 653 } else { 654 if (pgid == 0) { 655 /* 656 * zero pgid means send to my process group. 657 */ 658 pgrp = cp->p_pgrp; 659 } else { 660 pgrp = pgfind(pgid); 661 if (pgrp == NULL) 662 return (ESRCH); 663 } 664 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 665 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 666 if (p->p_pid <= 1 || 667 p->p_stat == SZOMB || 668 (p->p_flag & P_SYSTEM) || 669 !CANSIGNAL(p, sig)) { 670 continue; 671 } 672 ++info.nfound; 673 if (sig) 674 ksignal(p, sig); 675 } 676 lockmgr(&pgrp->pg_lock, LK_RELEASE); 677 } 678 return (info.nfound ? 0 : ESRCH); 679 } 680 681 static int 682 killpg_all_callback(struct proc *p, void *data) 683 { 684 struct killpg_info *info = data; 685 686 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 687 p == curproc || !CANSIGNAL(p, info->sig)) { 688 return (0); 689 } 690 ++info->nfound; 691 if (info->sig) 692 ksignal(p, info->sig); 693 return(0); 694 } 695 696 int 697 kern_kill(int sig, pid_t pid, lwpid_t tid) 698 { 699 struct thread *td = curthread; 700 struct proc *p = td->td_proc; 701 struct lwp *lp = NULL; 702 703 if ((u_int)sig > _SIG_MAXSIG) 704 return (EINVAL); 705 if (pid > 0) { 706 /* kill single process */ 707 if ((p = pfind(pid)) == NULL) 708 return (ESRCH); 709 if (!CANSIGNAL(p, sig)) 710 return (EPERM); 711 if (tid != -1) { 712 FOREACH_LWP_IN_PROC(lp, p) { 713 if (lp->lwp_tid == tid) 714 break; 715 } 716 if (lp == NULL) 717 return (ESRCH); 718 } 719 if (sig) 720 lwpsignal(p, lp, sig); 721 return (0); 722 } 723 /* 724 * If we come here, pid is a special broadcast pid. 725 * This doesn't mix with a tid. 726 */ 727 if (tid != -1) 728 return (EINVAL); 729 switch (pid) { 730 case -1: /* broadcast signal */ 731 return (dokillpg(sig, 0, 1)); 732 case 0: /* signal own process group */ 733 return (dokillpg(sig, 0, 0)); 734 default: /* negative explicit process group */ 735 return (dokillpg(sig, -pid, 0)); 736 } 737 /* NOTREACHED */ 738 } 739 740 int 741 sys_kill(struct kill_args *uap) 742 { 743 int error; 744 745 error = kern_kill(uap->signum, uap->pid, -1); 746 return (error); 747 } 748 749 int 750 sys_lwp_kill(struct lwp_kill_args *uap) 751 { 752 int error; 753 pid_t pid = uap->pid; 754 755 /* 756 * A tid is mandatory for lwp_kill(), otherwise 757 * you could simply use kill(). 758 */ 759 if (uap->tid == -1) 760 return (EINVAL); 761 762 /* 763 * To save on a getpid() function call for intra-process 764 * signals, pid == -1 means current process. 765 */ 766 if (pid == -1) 767 pid = curproc->p_pid; 768 769 error = kern_kill(uap->signum, pid, uap->tid); 770 return (error); 771 } 772 773 /* 774 * Send a signal to a process group. 775 */ 776 void 777 gsignal(int pgid, int sig) 778 { 779 struct pgrp *pgrp; 780 781 if (pgid && (pgrp = pgfind(pgid))) 782 pgsignal(pgrp, sig, 0); 783 } 784 785 /* 786 * Send a signal to a process group. If checktty is 1, 787 * limit to members which have a controlling terminal. 788 * 789 * pg_lock interlocks against a fork that might be in progress, to 790 * ensure that the new child process picks up the signal. 791 */ 792 void 793 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 794 { 795 struct proc *p; 796 797 if (pgrp) { 798 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 799 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 800 if (checkctty == 0 || p->p_flag & P_CONTROLT) 801 ksignal(p, sig); 802 } 803 lockmgr(&pgrp->pg_lock, LK_RELEASE); 804 } 805 } 806 807 /* 808 * Send a signal caused by a trap to the current process. 809 * If it will be caught immediately, deliver it with correct code. 810 * Otherwise, post it normally. 811 */ 812 void 813 trapsignal(struct lwp *lp, int sig, u_long code) 814 { 815 struct proc *p = lp->lwp_proc; 816 struct sigacts *ps = p->p_sigacts; 817 818 /* 819 * If we are a virtual kernel running an emulated user process 820 * context, switch back to the virtual kernel context before 821 * trying to post the signal. 822 */ 823 if (p->p_vkernel && p->p_vkernel->vk_current) { 824 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs; 825 tf->tf_trapno = 0; 826 vkernel_trap(p, tf); 827 } 828 829 830 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 831 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 832 lp->lwp_ru.ru_nsignals++; 833 #ifdef KTRACE 834 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 835 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)], 836 &lp->lwp_sigmask, code); 837 #endif 838 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 839 &lp->lwp_sigmask, code); 840 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 841 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 842 SIGADDSET(lp->lwp_sigmask, sig); 843 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 844 /* 845 * See kern_sigaction() for origin of this code. 846 */ 847 SIGDELSET(p->p_sigcatch, sig); 848 if (sig != SIGCONT && 849 sigprop(sig) & SA_IGNORE) 850 SIGADDSET(p->p_sigignore, sig); 851 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 852 } 853 } else { 854 lp->lwp_code = code; /* XXX for core dump/debugger */ 855 lp->lwp_sig = sig; /* XXX to verify code */ 856 lwpsignal(p, lp, sig); 857 } 858 } 859 860 /* 861 * Find a suitable lwp to deliver the signal to. 862 * 863 * Returns NULL if all lwps hold the signal blocked. 864 */ 865 static struct lwp * 866 find_lwp_for_signal(struct proc *p, int sig) 867 { 868 struct lwp *lp; 869 struct lwp *run, *sleep, *stop; 870 871 /* 872 * If the running/preempted thread belongs to the proc to which 873 * the signal is being delivered and this thread does not block 874 * the signal, then we can avoid a context switch by delivering 875 * the signal to this thread, because it will return to userland 876 * soon anyways. 877 */ 878 lp = lwkt_preempted_proc(); 879 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig)) 880 return (lp); 881 882 run = sleep = stop = NULL; 883 FOREACH_LWP_IN_PROC(lp, p) { 884 /* 885 * If the signal is being blocked by the lwp, then this 886 * lwp is not eligible for receiving the signal. 887 */ 888 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 889 continue; 890 891 switch (lp->lwp_stat) { 892 case LSRUN: 893 run = lp; 894 break; 895 896 case LSSTOP: 897 stop = lp; 898 break; 899 900 case LSSLEEP: 901 if (lp->lwp_flag & LWP_SINTR) 902 sleep = lp; 903 break; 904 } 905 } 906 907 if (run != NULL) 908 return (run); 909 else if (sleep != NULL) 910 return (sleep); 911 else 912 return (stop); 913 } 914 915 /* 916 * Send the signal to the process. If the signal has an action, the action 917 * is usually performed by the target process rather than the caller; we add 918 * the signal to the set of pending signals for the process. 919 * 920 * Exceptions: 921 * o When a stop signal is sent to a sleeping process that takes the 922 * default action, the process is stopped without awakening it. 923 * o SIGCONT restarts stopped processes (or puts them back to sleep) 924 * regardless of the signal action (eg, blocked or ignored). 925 * 926 * Other ignored signals are discarded immediately. 927 */ 928 void 929 ksignal(struct proc *p, int sig) 930 { 931 lwpsignal(p, NULL, sig); 932 } 933 934 /* 935 * The core for ksignal. lp may be NULL, then a suitable thread 936 * will be chosen. If not, lp MUST be a member of p. 937 */ 938 void 939 lwpsignal(struct proc *p, struct lwp *lp, int sig) 940 { 941 int prop; 942 sig_t action; 943 944 if (sig > _SIG_MAXSIG || sig <= 0) { 945 kprintf("lwpsignal: signal %d\n", sig); 946 panic("lwpsignal signal number"); 947 } 948 949 KKASSERT(lp == NULL || lp->lwp_proc == p); 950 951 crit_enter(); 952 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 953 crit_exit(); 954 955 prop = sigprop(sig); 956 957 /* 958 * If proc is traced, always give parent a chance; 959 * if signal event is tracked by procfs, give *that* 960 * a chance, as well. 961 */ 962 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 963 action = SIG_DFL; 964 } else { 965 /* 966 * Do not try to deliver signals to an exiting process or 967 * exiting lwp. 968 */ 969 if (p->p_flag & P_WEXIT) 970 return; 971 if (lp && (lp->lwp_flag & LWP_WEXIT)) 972 return; 973 974 /* 975 * Ig the signal is being ignored, then we forget about 976 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 977 * and if it is set to SIG_IGN, action will be SIG_DFL here. 978 */ 979 if (SIGISMEMBER(p->p_sigignore, sig)) 980 return; 981 if (SIGISMEMBER(p->p_sigcatch, sig)) 982 action = SIG_CATCH; 983 else 984 action = SIG_DFL; 985 } 986 987 /* 988 * If continuing, clear any pending STOP signals. 989 */ 990 if (prop & SA_CONT) 991 SIG_STOPSIGMASK(p->p_siglist); 992 993 if (prop & SA_STOP) { 994 /* 995 * If sending a tty stop signal to a member of an orphaned 996 * process group, discard the signal here if the action 997 * is default; don't stop the process below if sleeping, 998 * and don't clear any pending SIGCONT. 999 */ 1000 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1001 action == SIG_DFL) { 1002 return; 1003 } 1004 SIG_CONTSIGMASK(p->p_siglist); 1005 } 1006 1007 crit_enter(); 1008 1009 if (p->p_stat == SSTOP) { 1010 /* 1011 * Nobody can handle this signal, so add it to the process 1012 * pending list. 1013 */ 1014 SIGADDSET(p->p_siglist, sig); 1015 1016 /* 1017 * If the process is stopped and is being traced, then no 1018 * further action is necessary. 1019 */ 1020 if (p->p_flag & P_TRACED) 1021 goto out; 1022 1023 /* 1024 * If the process is stopped and receives a KILL signal, 1025 * make the process runnable. 1026 */ 1027 if (sig == SIGKILL) { 1028 proc_unstop(p); 1029 goto active_process; 1030 } 1031 1032 /* 1033 * If the process is stopped and receives a CONT signal, 1034 * then try to make the process runnable again. 1035 */ 1036 if (prop & SA_CONT) { 1037 /* 1038 * If SIGCONT is default (or ignored), we continue the 1039 * process but don't leave the signal in p_siglist, as 1040 * it has no further action. If SIGCONT is held, we 1041 * continue the process and leave the signal in 1042 * p_siglist. If the process catches SIGCONT, let it 1043 * handle the signal itself. 1044 */ 1045 /* XXX what if the signal is being held blocked? */ 1046 if (action == SIG_DFL) 1047 SIGDELSET(p->p_siglist, sig); 1048 proc_unstop(p); 1049 if (action == SIG_CATCH) 1050 goto active_process; 1051 goto out; 1052 } 1053 1054 /* 1055 * If the process is stopped and receives another STOP 1056 * signal, we do not need to stop it again. If we did 1057 * the shell could get confused. 1058 * 1059 * However, if the current/preempted lwp is part of the 1060 * process receiving the signal, we need to keep it, 1061 * so that this lwp can stop in issignal() later, as 1062 * we don't want to wait until it reaches userret! 1063 */ 1064 if (prop & SA_STOP) { 1065 if (lwkt_preempted_proc() == NULL || 1066 lwkt_preempted_proc()->lwp_proc != p) 1067 SIGDELSET(p->p_siglist, sig); 1068 } 1069 1070 /* 1071 * Otherwise the process is stopped and it received some 1072 * signal, which does not change its stopped state. 1073 * 1074 * We have to select one thread to set LWP_BREAKTSLEEP, 1075 * so that the current signal will break the sleep 1076 * as soon as a SA_CONT signal will unstop the process. 1077 */ 1078 if (lp == NULL) 1079 lp = find_lwp_for_signal(p, sig); 1080 if (lp != NULL && 1081 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1082 lp->lwp_flag |= LWP_BREAKTSLEEP; 1083 goto out; 1084 1085 /* NOTREACHED */ 1086 } 1087 /* else not stopped */ 1088 active_process: 1089 1090 if (lp == NULL) 1091 lp = find_lwp_for_signal(p, sig); 1092 1093 /* 1094 * If lp == NULL, there is no thread available which does 1095 * not block the signal. If lp is set, it might be a thread 1096 * specific signal, so we have to check for the thread ignoring 1097 * the signal. 1098 * 1099 * If so, defer further processing for this signal. 1100 * Add the signal to the process pending list. 1101 */ 1102 if (lp == NULL || SIGISMEMBER(lp->lwp_sigmask, sig)) { 1103 SIGADDSET(p->p_siglist, sig); 1104 goto out; 1105 } 1106 /* else we have a lwp to deliver the signal to */ 1107 1108 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1109 (p->p_flag & P_TRACED) == 0) { 1110 p->p_nice = NZERO; 1111 } 1112 1113 /* 1114 * If the process receives a STOP signal which indeed needs to 1115 * stop the process, do so. If the process chose to catch the 1116 * signal, it will be treated like any other signal. 1117 */ 1118 if ((prop & SA_STOP) && action == SIG_DFL) { 1119 /* 1120 * If a child holding parent blocked, stopping 1121 * could cause deadlock. Take no action at this 1122 * time. 1123 */ 1124 if (p->p_flag & P_PPWAIT) { 1125 SIGADDSET(p->p_siglist, sig); 1126 goto out; 1127 } 1128 1129 /* 1130 * Do not actually try to manipulate the process, but simply 1131 * stop it. Lwps will stop as soon as they safely can. 1132 */ 1133 p->p_xstat = sig; 1134 proc_stop(p); 1135 goto out; 1136 } 1137 1138 /* 1139 * If it is a CONT signal with default action, just ignore it. 1140 */ 1141 if ((prop & SA_CONT) && action == SIG_DFL) 1142 goto out; 1143 1144 /* 1145 * Mark signal pending at this specific thread. 1146 */ 1147 SIGADDSET(lp->lwp_siglist, sig); 1148 1149 lwp_signotify(lp); 1150 1151 out: 1152 crit_exit(); 1153 } 1154 1155 void 1156 lwp_signotify(struct lwp *lp) 1157 { 1158 crit_enter(); 1159 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1160 /* 1161 * Thread is in tsleep. 1162 */ 1163 1164 /* 1165 * If the thread is sleeping uninterruptibly 1166 * we can't interrupt the sleep... the signal will 1167 * be noticed when the lwp returns through 1168 * trap() or syscall(). 1169 * 1170 * Otherwise the signal can interrupt the sleep. 1171 * 1172 * If the process is traced, the lwp will handle the 1173 * tracing in issignal() when it returns to userland. 1174 */ 1175 if (lp->lwp_flag & LWP_SINTR) { 1176 /* 1177 * Make runnable and break out of any tsleep as well. 1178 */ 1179 lp->lwp_flag |= LWP_BREAKTSLEEP; 1180 setrunnable(lp); 1181 } 1182 } else { 1183 /* 1184 * Otherwise the thread is running 1185 * 1186 * LSRUN does nothing with the signal, other than kicking 1187 * ourselves if we are running. 1188 * SZOMB and SIDL mean that it will either never be noticed, 1189 * or noticed very soon. 1190 * 1191 * Note that lwp_thread may be NULL or may not be completely 1192 * initialized if the process is in the SIDL or SZOMB state. 1193 * 1194 * For SMP we may have to forward the request to another cpu. 1195 * YYY the MP lock prevents the target process from moving 1196 * to another cpu, see kern/kern_switch.c 1197 * 1198 * If the target thread is waiting on its message port, 1199 * wakeup the target thread so it can check (or ignore) 1200 * the new signal. YYY needs cleanup. 1201 */ 1202 if (lp == lwkt_preempted_proc()) { 1203 signotify(); 1204 } else if (lp->lwp_stat == LSRUN) { 1205 struct thread *td = lp->lwp_thread; 1206 struct proc *p = lp->lwp_proc; 1207 1208 KASSERT(td != NULL, 1209 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1210 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1211 p->p_flag, lp->lwp_flag)); 1212 1213 #ifdef SMP 1214 if (td->td_gd != mycpu) 1215 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1216 else 1217 #endif 1218 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1219 lwkt_schedule(td); 1220 } 1221 } 1222 crit_exit(); 1223 } 1224 1225 #ifdef SMP 1226 1227 /* 1228 * This function is called via an IPI. We will be in a critical section but 1229 * the MP lock will NOT be held. Also note that by the time the ipi message 1230 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1231 */ 1232 static void 1233 signotify_remote(void *arg) 1234 { 1235 struct lwp *lp = arg; 1236 1237 if (lp == lwkt_preempted_proc()) { 1238 signotify(); 1239 } else { 1240 struct thread *td = lp->lwp_thread; 1241 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1242 lwkt_schedule(td); 1243 } 1244 } 1245 1246 #endif 1247 1248 void 1249 proc_stop(struct proc *p) 1250 { 1251 struct lwp *lp; 1252 1253 /* If somebody raced us, be happy with it */ 1254 if (p->p_stat == SSTOP) 1255 return; 1256 1257 crit_enter(); 1258 p->p_stat = SSTOP; 1259 1260 FOREACH_LWP_IN_PROC(lp, p) { 1261 switch (lp->lwp_stat) { 1262 case LSSTOP: 1263 /* 1264 * Do nothing, we are already counted in 1265 * p_nstopped. 1266 */ 1267 break; 1268 1269 case LSSLEEP: 1270 /* 1271 * We're sleeping, but we will stop before 1272 * returning to userspace, so count us 1273 * as stopped as well. We set LWP_WSTOP 1274 * to signal the lwp that it should not 1275 * increase p_nstopped when reaching tstop(). 1276 */ 1277 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1278 lp->lwp_flag |= LWP_WSTOP; 1279 ++p->p_nstopped; 1280 } 1281 break; 1282 1283 case LSRUN: 1284 /* 1285 * We might notify ourself, but that's not 1286 * a problem. 1287 */ 1288 lwp_signotify(lp); 1289 break; 1290 } 1291 } 1292 1293 if (p->p_nstopped == p->p_nthreads) { 1294 p->p_flag &= ~P_WAITED; 1295 wakeup(p->p_pptr); 1296 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1297 ksignal(p->p_pptr, SIGCHLD); 1298 } 1299 crit_exit(); 1300 } 1301 1302 void 1303 proc_unstop(struct proc *p) 1304 { 1305 struct lwp *lp; 1306 1307 if (p->p_stat != SSTOP) 1308 return; 1309 1310 crit_enter(); 1311 p->p_stat = SACTIVE; 1312 1313 FOREACH_LWP_IN_PROC(lp, p) { 1314 switch (lp->lwp_stat) { 1315 case LSRUN: 1316 /* 1317 * Uh? Not stopped? Well, I guess that's okay. 1318 */ 1319 if (bootverbose) 1320 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1321 p->p_pid, lp->lwp_tid); 1322 break; 1323 1324 case LSSLEEP: 1325 /* 1326 * Still sleeping. Don't bother waking it up. 1327 * However, if this thread was counted as 1328 * stopped, undo this. 1329 * 1330 * Nevertheless we call setrunnable() so that it 1331 * will wake up in case a signal or timeout arrived 1332 * in the meantime. 1333 */ 1334 if (lp->lwp_flag & LWP_WSTOP) { 1335 --p->p_nstopped; 1336 } else { 1337 if (bootverbose) 1338 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1339 p->p_pid, lp->lwp_tid); 1340 } 1341 /* FALLTHROUGH */ 1342 1343 case LSSTOP: 1344 setrunnable(lp); 1345 break; 1346 1347 } 1348 lp->lwp_flag &= ~LWP_WSTOP; 1349 } 1350 crit_exit(); 1351 } 1352 1353 static int 1354 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1355 { 1356 sigset_t savedmask, set; 1357 struct proc *p = curproc; 1358 struct lwp *lp = curthread->td_lwp; 1359 int error, sig, hz, timevalid = 0; 1360 struct timespec rts, ets, ts; 1361 struct timeval tv; 1362 1363 error = 0; 1364 sig = 0; 1365 SIG_CANTMASK(waitset); 1366 savedmask = lp->lwp_sigmask; 1367 1368 if (timeout) { 1369 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1370 timeout->tv_nsec < 1000000000) { 1371 timevalid = 1; 1372 getnanouptime(&rts); 1373 ets = rts; 1374 timespecadd(&ets, timeout); 1375 } 1376 } 1377 1378 for (;;) { 1379 set = lwp_sigpend(lp); 1380 SIGSETAND(set, waitset); 1381 if ((sig = sig_ffs(&set)) != 0) { 1382 SIGFILLSET(lp->lwp_sigmask); 1383 SIGDELSET(lp->lwp_sigmask, sig); 1384 SIG_CANTMASK(lp->lwp_sigmask); 1385 sig = issignal(lp); 1386 /* 1387 * It may be a STOP signal, in the case, issignal 1388 * returns 0, because we may stop there, and new 1389 * signal can come in, we should restart if we got 1390 * nothing. 1391 */ 1392 if (sig == 0) 1393 continue; 1394 else 1395 break; 1396 } 1397 1398 /* 1399 * Previous checking got nothing, and we retried but still 1400 * got nothing, we should return the error status. 1401 */ 1402 if (error) 1403 break; 1404 1405 /* 1406 * POSIX says this must be checked after looking for pending 1407 * signals. 1408 */ 1409 if (timeout) { 1410 if (!timevalid) { 1411 error = EINVAL; 1412 break; 1413 } 1414 getnanouptime(&rts); 1415 if (timespeccmp(&rts, &ets, >=)) { 1416 error = EAGAIN; 1417 break; 1418 } 1419 ts = ets; 1420 timespecsub(&ts, &rts); 1421 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1422 hz = tvtohz_high(&tv); 1423 } else 1424 hz = 0; 1425 1426 lp->lwp_sigmask = savedmask; 1427 SIGSETNAND(lp->lwp_sigmask, waitset); 1428 /* 1429 * We won't ever be woken up. Instead, our sleep will 1430 * be broken in lwpsignal(). 1431 */ 1432 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1433 if (timeout) { 1434 if (error == ERESTART) { 1435 /* can not restart a timeout wait. */ 1436 error = EINTR; 1437 } else if (error == EAGAIN) { 1438 /* will calculate timeout by ourself. */ 1439 error = 0; 1440 } 1441 } 1442 /* Retry ... */ 1443 } 1444 1445 lp->lwp_sigmask = savedmask; 1446 if (sig) { 1447 error = 0; 1448 bzero(info, sizeof(*info)); 1449 info->si_signo = sig; 1450 lwp_delsig(lp, sig); /* take the signal! */ 1451 1452 if (sig == SIGKILL) 1453 sigexit(p, sig); 1454 } 1455 return (error); 1456 } 1457 1458 int 1459 sys_sigtimedwait(struct sigtimedwait_args *uap) 1460 { 1461 struct timespec ts; 1462 struct timespec *timeout; 1463 sigset_t set; 1464 siginfo_t info; 1465 int error; 1466 1467 if (uap->timeout) { 1468 error = copyin(uap->timeout, &ts, sizeof(ts)); 1469 if (error) 1470 return (error); 1471 timeout = &ts; 1472 } else { 1473 timeout = NULL; 1474 } 1475 error = copyin(uap->set, &set, sizeof(set)); 1476 if (error) 1477 return (error); 1478 error = kern_sigtimedwait(set, &info, timeout); 1479 if (error) 1480 return (error); 1481 if (uap->info) 1482 error = copyout(&info, uap->info, sizeof(info)); 1483 /* Repost if we got an error. */ 1484 /* 1485 * XXX lwp 1486 * 1487 * This could transform a thread-specific signal to another 1488 * thread / process pending signal. 1489 */ 1490 if (error) 1491 ksignal(curproc, info.si_signo); 1492 else 1493 uap->sysmsg_result = info.si_signo; 1494 return (error); 1495 } 1496 1497 int 1498 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1499 { 1500 siginfo_t info; 1501 sigset_t set; 1502 int error; 1503 1504 error = copyin(uap->set, &set, sizeof(set)); 1505 if (error) 1506 return (error); 1507 error = kern_sigtimedwait(set, &info, NULL); 1508 if (error) 1509 return (error); 1510 if (uap->info) 1511 error = copyout(&info, uap->info, sizeof(info)); 1512 /* Repost if we got an error. */ 1513 /* 1514 * XXX lwp 1515 * 1516 * This could transform a thread-specific signal to another 1517 * thread / process pending signal. 1518 */ 1519 if (error) 1520 ksignal(curproc, info.si_signo); 1521 else 1522 uap->sysmsg_result = info.si_signo; 1523 return (error); 1524 } 1525 1526 /* 1527 * If the current process has received a signal that would interrupt a 1528 * system call, return EINTR or ERESTART as appropriate. 1529 */ 1530 int 1531 iscaught(struct lwp *lp) 1532 { 1533 struct proc *p = lp->lwp_proc; 1534 int sig; 1535 1536 if (p) { 1537 if ((sig = CURSIG(lp)) != 0) { 1538 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1539 return (EINTR); 1540 return (ERESTART); 1541 } 1542 } 1543 return(EWOULDBLOCK); 1544 } 1545 1546 /* 1547 * If the current process has received a signal (should be caught or cause 1548 * termination, should interrupt current syscall), return the signal number. 1549 * Stop signals with default action are processed immediately, then cleared; 1550 * they aren't returned. This is checked after each entry to the system for 1551 * a syscall or trap (though this can usually be done without calling issignal 1552 * by checking the pending signal masks in the CURSIG macro.) The normal call 1553 * sequence is 1554 * 1555 * This routine is called via CURSIG/__cursig and the MP lock might not be 1556 * held. Obtain the MP lock for the duration of the operation. 1557 * 1558 * while (sig = CURSIG(curproc)) 1559 * postsig(sig); 1560 */ 1561 int 1562 issignal(struct lwp *lp) 1563 { 1564 struct proc *p = lp->lwp_proc; 1565 sigset_t mask; 1566 int sig, prop; 1567 1568 get_mplock(); 1569 for (;;) { 1570 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1571 1572 mask = lwp_sigpend(lp); 1573 SIGSETNAND(mask, lp->lwp_sigmask); 1574 if (p->p_flag & P_PPWAIT) 1575 SIG_STOPSIGMASK(mask); 1576 if (SIGISEMPTY(mask)) { /* no signal to send */ 1577 rel_mplock(); 1578 return (0); 1579 } 1580 sig = sig_ffs(&mask); 1581 1582 STOPEVENT(p, S_SIG, sig); 1583 1584 /* 1585 * We should see pending but ignored signals 1586 * only if P_TRACED was on when they were posted. 1587 */ 1588 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1589 lwp_delsig(lp, sig); 1590 continue; 1591 } 1592 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1593 /* 1594 * If traced, always stop, and stay stopped until 1595 * released by the parent. 1596 * 1597 * NOTE: SSTOP may get cleared during the loop, 1598 * but we do not re-notify the parent if we have 1599 * to loop several times waiting for the parent 1600 * to let us continue. 1601 * 1602 * XXX not sure if this is still true 1603 */ 1604 p->p_xstat = sig; 1605 proc_stop(p); 1606 do { 1607 tstop(); 1608 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1609 1610 /* 1611 * If parent wants us to take the signal, 1612 * then it will leave it in p->p_xstat; 1613 * otherwise we just look for signals again. 1614 */ 1615 lwp_delsig(lp, sig); /* clear old signal */ 1616 sig = p->p_xstat; 1617 if (sig == 0) 1618 continue; 1619 1620 /* 1621 * Put the new signal into p_siglist. If the 1622 * signal is being masked, look for other signals. 1623 * 1624 * XXX lwp might need a call to ksignal() 1625 */ 1626 SIGADDSET(p->p_siglist, sig); 1627 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1628 continue; 1629 1630 /* 1631 * If the traced bit got turned off, go back up 1632 * to the top to rescan signals. This ensures 1633 * that p_sig* and ps_sigact are consistent. 1634 */ 1635 if ((p->p_flag & P_TRACED) == 0) 1636 continue; 1637 } 1638 1639 prop = sigprop(sig); 1640 1641 /* 1642 * Decide whether the signal should be returned. 1643 * Return the signal's number, or fall through 1644 * to clear it from the pending mask. 1645 */ 1646 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1647 case (int)SIG_DFL: 1648 /* 1649 * Don't take default actions on system processes. 1650 */ 1651 if (p->p_pid <= 1) { 1652 #ifdef DIAGNOSTIC 1653 /* 1654 * Are you sure you want to ignore SIGSEGV 1655 * in init? XXX 1656 */ 1657 kprintf("Process (pid %lu) got signal %d\n", 1658 (u_long)p->p_pid, sig); 1659 #endif 1660 break; /* == ignore */ 1661 } 1662 1663 /* 1664 * Handle the in-kernel checkpoint action 1665 */ 1666 if (prop & SA_CKPT) { 1667 checkpoint_signal_handler(lp); 1668 break; 1669 } 1670 1671 /* 1672 * If there is a pending stop signal to process 1673 * with default action, stop here, 1674 * then clear the signal. However, 1675 * if process is member of an orphaned 1676 * process group, ignore tty stop signals. 1677 */ 1678 if (prop & SA_STOP) { 1679 if (p->p_flag & P_TRACED || 1680 (p->p_pgrp->pg_jobc == 0 && 1681 prop & SA_TTYSTOP)) 1682 break; /* == ignore */ 1683 p->p_xstat = sig; 1684 proc_stop(p); 1685 while (p->p_stat == SSTOP) { 1686 tstop(); 1687 } 1688 break; 1689 } else if (prop & SA_IGNORE) { 1690 /* 1691 * Except for SIGCONT, shouldn't get here. 1692 * Default action is to ignore; drop it. 1693 */ 1694 break; /* == ignore */ 1695 } else { 1696 rel_mplock(); 1697 return (sig); 1698 } 1699 1700 /*NOTREACHED*/ 1701 1702 case (int)SIG_IGN: 1703 /* 1704 * Masking above should prevent us ever trying 1705 * to take action on an ignored signal other 1706 * than SIGCONT, unless process is traced. 1707 */ 1708 if ((prop & SA_CONT) == 0 && 1709 (p->p_flag & P_TRACED) == 0) 1710 kprintf("issignal\n"); 1711 break; /* == ignore */ 1712 1713 default: 1714 /* 1715 * This signal has an action, let 1716 * postsig() process it. 1717 */ 1718 rel_mplock(); 1719 return (sig); 1720 } 1721 lwp_delsig(lp, sig); /* take the signal! */ 1722 } 1723 /* NOTREACHED */ 1724 } 1725 1726 /* 1727 * Take the action for the specified signal 1728 * from the current set of pending signals. 1729 */ 1730 void 1731 postsig(int sig) 1732 { 1733 struct lwp *lp = curthread->td_lwp; 1734 struct proc *p = lp->lwp_proc; 1735 struct sigacts *ps = p->p_sigacts; 1736 sig_t action; 1737 sigset_t returnmask; 1738 int code; 1739 1740 KASSERT(sig != 0, ("postsig")); 1741 1742 /* 1743 * If we are a virtual kernel running an emulated user process 1744 * context, switch back to the virtual kernel context before 1745 * trying to post the signal. 1746 */ 1747 if (p->p_vkernel && p->p_vkernel->vk_current) { 1748 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs; 1749 tf->tf_trapno = 0; 1750 vkernel_trap(p, tf); 1751 } 1752 1753 lwp_delsig(lp, sig); 1754 action = ps->ps_sigact[_SIG_IDX(sig)]; 1755 #ifdef KTRACE 1756 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1757 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1758 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1759 #endif 1760 STOPEVENT(p, S_SIG, sig); 1761 1762 if (action == SIG_DFL) { 1763 /* 1764 * Default action, where the default is to kill 1765 * the process. (Other cases were ignored above.) 1766 */ 1767 sigexit(p, sig); 1768 /* NOTREACHED */ 1769 } else { 1770 /* 1771 * If we get here, the signal must be caught. 1772 */ 1773 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1774 ("postsig action")); 1775 1776 crit_enter(); 1777 1778 /* 1779 * Reset the signal handler if asked to 1780 */ 1781 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1782 /* 1783 * See kern_sigaction() for origin of this code. 1784 */ 1785 SIGDELSET(p->p_sigcatch, sig); 1786 if (sig != SIGCONT && 1787 sigprop(sig) & SA_IGNORE) 1788 SIGADDSET(p->p_sigignore, sig); 1789 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1790 } 1791 1792 /* 1793 * Handle the mailbox case. Copyout to the appropriate 1794 * location but do not generate a signal frame. The system 1795 * call simply returns EINTR and the user is responsible for 1796 * polling the mailbox. 1797 */ 1798 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1799 int sig_copy = sig; 1800 copyout(&sig_copy, (void *)action, sizeof(int)); 1801 curproc->p_flag |= P_MAILBOX; 1802 crit_exit(); 1803 goto done; 1804 } 1805 1806 /* 1807 * Set the signal mask and calculate the mask to restore 1808 * when the signal function returns. 1809 * 1810 * Special case: user has done a sigsuspend. Here the 1811 * current mask is not of interest, but rather the 1812 * mask from before the sigsuspend is what we want 1813 * restored after the signal processing is completed. 1814 */ 1815 if (lp->lwp_flag & LWP_OLDMASK) { 1816 returnmask = lp->lwp_oldsigmask; 1817 lp->lwp_flag &= ~LWP_OLDMASK; 1818 } else { 1819 returnmask = lp->lwp_sigmask; 1820 } 1821 1822 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1823 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1824 SIGADDSET(lp->lwp_sigmask, sig); 1825 1826 crit_exit(); 1827 lp->lwp_ru.ru_nsignals++; 1828 if (lp->lwp_sig != sig) { 1829 code = 0; 1830 } else { 1831 code = lp->lwp_code; 1832 lp->lwp_code = 0; 1833 lp->lwp_sig = 0; 1834 } 1835 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1836 } 1837 done: 1838 ; 1839 } 1840 1841 /* 1842 * Kill the current process for stated reason. 1843 */ 1844 void 1845 killproc(struct proc *p, char *why) 1846 { 1847 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1848 p->p_pid, p->p_comm, 1849 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1850 ksignal(p, SIGKILL); 1851 } 1852 1853 /* 1854 * Force the current process to exit with the specified signal, dumping core 1855 * if appropriate. We bypass the normal tests for masked and caught signals, 1856 * allowing unrecoverable failures to terminate the process without changing 1857 * signal state. Mark the accounting record with the signal termination. 1858 * If dumping core, save the signal number for the debugger. Calls exit and 1859 * does not return. 1860 */ 1861 void 1862 sigexit(struct proc *p, int sig) 1863 { 1864 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */ 1865 1866 p->p_acflag |= AXSIG; 1867 if (sigprop(sig) & SA_CORE) { 1868 lp->lwp_sig = sig; 1869 /* 1870 * Log signals which would cause core dumps 1871 * (Log as LOG_INFO to appease those who don't want 1872 * these messages.) 1873 * XXX : Todo, as well as euid, write out ruid too 1874 */ 1875 if (coredump(lp, sig) == 0) 1876 sig |= WCOREFLAG; 1877 if (kern_logsigexit) 1878 log(LOG_INFO, 1879 "pid %d (%s), uid %d: exited on signal %d%s\n", 1880 p->p_pid, p->p_comm, 1881 p->p_ucred ? p->p_ucred->cr_uid : -1, 1882 sig &~ WCOREFLAG, 1883 sig & WCOREFLAG ? " (core dumped)" : ""); 1884 } 1885 exit1(W_EXITCODE(0, sig)); 1886 /* NOTREACHED */ 1887 } 1888 1889 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1890 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1891 sizeof(corefilename), "process corefile name format string"); 1892 1893 /* 1894 * expand_name(name, uid, pid) 1895 * Expand the name described in corefilename, using name, uid, and pid. 1896 * corefilename is a kprintf-like string, with three format specifiers: 1897 * %N name of process ("name") 1898 * %P process id (pid) 1899 * %U user id (uid) 1900 * For example, "%N.core" is the default; they can be disabled completely 1901 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1902 * This is controlled by the sysctl variable kern.corefile (see above). 1903 */ 1904 1905 static char * 1906 expand_name(const char *name, uid_t uid, pid_t pid) 1907 { 1908 char *temp; 1909 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1910 int i, n; 1911 char *format = corefilename; 1912 size_t namelen; 1913 1914 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1915 if (temp == NULL) 1916 return NULL; 1917 namelen = strlen(name); 1918 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1919 int l; 1920 switch (format[i]) { 1921 case '%': /* Format character */ 1922 i++; 1923 switch (format[i]) { 1924 case '%': 1925 temp[n++] = '%'; 1926 break; 1927 case 'N': /* process name */ 1928 if ((n + namelen) > MAXPATHLEN) { 1929 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1930 pid, name, uid, temp, name); 1931 kfree(temp, M_TEMP); 1932 return NULL; 1933 } 1934 memcpy(temp+n, name, namelen); 1935 n += namelen; 1936 break; 1937 case 'P': /* process id */ 1938 l = ksprintf(buf, "%u", pid); 1939 if ((n + l) > MAXPATHLEN) { 1940 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1941 pid, name, uid, temp, name); 1942 kfree(temp, M_TEMP); 1943 return NULL; 1944 } 1945 memcpy(temp+n, buf, l); 1946 n += l; 1947 break; 1948 case 'U': /* user id */ 1949 l = ksprintf(buf, "%u", uid); 1950 if ((n + l) > MAXPATHLEN) { 1951 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1952 pid, name, uid, temp, name); 1953 kfree(temp, M_TEMP); 1954 return NULL; 1955 } 1956 memcpy(temp+n, buf, l); 1957 n += l; 1958 break; 1959 default: 1960 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1961 } 1962 break; 1963 default: 1964 temp[n++] = format[i]; 1965 } 1966 } 1967 temp[n] = '\0'; 1968 return temp; 1969 } 1970 1971 /* 1972 * Dump a process' core. The main routine does some 1973 * policy checking, and creates the name of the coredump; 1974 * then it passes on a vnode and a size limit to the process-specific 1975 * coredump routine if there is one; if there _is not_ one, it returns 1976 * ENOSYS; otherwise it returns the error from the process-specific routine. 1977 * 1978 * The parameter `lp' is the lwp which triggered the coredump. 1979 */ 1980 1981 static int 1982 coredump(struct lwp *lp, int sig) 1983 { 1984 struct proc *p = lp->lwp_proc; 1985 struct vnode *vp; 1986 struct ucred *cred = p->p_ucred; 1987 struct flock lf; 1988 struct nlookupdata nd; 1989 struct vattr vattr; 1990 int error, error1; 1991 char *name; /* name of corefile */ 1992 off_t limit; 1993 1994 STOPEVENT(p, S_CORE, 0); 1995 1996 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1997 return (EFAULT); 1998 1999 /* 2000 * Note that the bulk of limit checking is done after 2001 * the corefile is created. The exception is if the limit 2002 * for corefiles is 0, in which case we don't bother 2003 * creating the corefile at all. This layout means that 2004 * a corefile is truncated instead of not being created, 2005 * if it is larger than the limit. 2006 */ 2007 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2008 if (limit == 0) 2009 return EFBIG; 2010 2011 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2012 if (name == NULL) 2013 return (EINVAL); 2014 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2015 if (error == 0) 2016 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2017 kfree(name, M_TEMP); 2018 if (error) { 2019 nlookup_done(&nd); 2020 return (error); 2021 } 2022 vp = nd.nl_open_vp; 2023 nd.nl_open_vp = NULL; 2024 nlookup_done(&nd); 2025 2026 vn_unlock(vp); 2027 lf.l_whence = SEEK_SET; 2028 lf.l_start = 0; 2029 lf.l_len = 0; 2030 lf.l_type = F_WRLCK; 2031 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2032 if (error) 2033 goto out2; 2034 2035 /* Don't dump to non-regular files or files with links. */ 2036 if (vp->v_type != VREG || 2037 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2038 error = EFAULT; 2039 goto out1; 2040 } 2041 2042 VATTR_NULL(&vattr); 2043 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2044 vattr.va_size = 0; 2045 VOP_SETATTR(vp, &vattr, cred); 2046 p->p_acflag |= ACORE; 2047 vn_unlock(vp); 2048 2049 error = p->p_sysent->sv_coredump ? 2050 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2051 2052 out1: 2053 lf.l_type = F_UNLCK; 2054 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2055 out2: 2056 error1 = vn_close(vp, FWRITE); 2057 if (error == 0) 2058 error = error1; 2059 return (error); 2060 } 2061 2062 /* 2063 * Nonexistent system call-- signal process (may want to handle it). 2064 * Flag error in case process won't see signal immediately (blocked or ignored). 2065 */ 2066 /* ARGSUSED */ 2067 int 2068 sys_nosys(struct nosys_args *args) 2069 { 2070 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2071 return (EINVAL); 2072 } 2073 2074 /* 2075 * Send a SIGIO or SIGURG signal to a process or process group using 2076 * stored credentials rather than those of the current process. 2077 */ 2078 void 2079 pgsigio(struct sigio *sigio, int sig, int checkctty) 2080 { 2081 if (sigio == NULL) 2082 return; 2083 2084 if (sigio->sio_pgid > 0) { 2085 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2086 sigio->sio_proc)) 2087 ksignal(sigio->sio_proc, sig); 2088 } else if (sigio->sio_pgid < 0) { 2089 struct proc *p; 2090 2091 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2092 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2093 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2094 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2095 ksignal(p, sig); 2096 } 2097 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2098 } 2099 } 2100 2101 static int 2102 filt_sigattach(struct knote *kn) 2103 { 2104 struct proc *p = curproc; 2105 2106 kn->kn_ptr.p_proc = p; 2107 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2108 2109 /* XXX lock the proc here while adding to the list? */ 2110 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2111 2112 return (0); 2113 } 2114 2115 static void 2116 filt_sigdetach(struct knote *kn) 2117 { 2118 struct proc *p = kn->kn_ptr.p_proc; 2119 2120 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2121 } 2122 2123 /* 2124 * signal knotes are shared with proc knotes, so we apply a mask to 2125 * the hint in order to differentiate them from process hints. This 2126 * could be avoided by using a signal-specific knote list, but probably 2127 * isn't worth the trouble. 2128 */ 2129 static int 2130 filt_signal(struct knote *kn, long hint) 2131 { 2132 if (hint & NOTE_SIGNAL) { 2133 hint &= ~NOTE_SIGNAL; 2134 2135 if (kn->kn_id == hint) 2136 kn->kn_data++; 2137 } 2138 return (kn->kn_data != 0); 2139 } 2140