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 1.83 2007/08/15 03:15:06 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 /* 697 * Send a general signal to a process or LWPs within that process. Note 698 * that new signals cannot be sent if a process is exiting. 699 */ 700 int 701 kern_kill(int sig, pid_t pid, lwpid_t tid) 702 { 703 struct thread *td = curthread; 704 struct proc *p = td->td_proc; 705 struct lwp *lp = NULL; 706 707 if ((u_int)sig > _SIG_MAXSIG) 708 return (EINVAL); 709 if (pid > 0) { 710 /* kill single process */ 711 if ((p = pfind(pid)) == NULL) 712 return (ESRCH); 713 if (!CANSIGNAL(p, sig)) 714 return (EPERM); 715 716 /* 717 * NOP if the process is exiting. Note that lwpsignal() is 718 * called directly with P_WEXIT set to kill individual LWPs 719 * during exit, which is allowed. 720 */ 721 if (p->p_flag & P_WEXIT) 722 return (0); 723 if (tid != -1) { 724 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 725 if (lp == NULL) 726 return (ESRCH); 727 } 728 if (sig) 729 lwpsignal(p, lp, sig); 730 return (0); 731 } 732 /* 733 * If we come here, pid is a special broadcast pid. 734 * This doesn't mix with a tid. 735 */ 736 if (tid != -1) 737 return (EINVAL); 738 switch (pid) { 739 case -1: /* broadcast signal */ 740 return (dokillpg(sig, 0, 1)); 741 case 0: /* signal own process group */ 742 return (dokillpg(sig, 0, 0)); 743 default: /* negative explicit process group */ 744 return (dokillpg(sig, -pid, 0)); 745 } 746 /* NOTREACHED */ 747 } 748 749 int 750 sys_kill(struct kill_args *uap) 751 { 752 int error; 753 754 error = kern_kill(uap->signum, uap->pid, -1); 755 return (error); 756 } 757 758 int 759 sys_lwp_kill(struct lwp_kill_args *uap) 760 { 761 int error; 762 pid_t pid = uap->pid; 763 764 /* 765 * A tid is mandatory for lwp_kill(), otherwise 766 * you could simply use kill(). 767 */ 768 if (uap->tid == -1) 769 return (EINVAL); 770 771 /* 772 * To save on a getpid() function call for intra-process 773 * signals, pid == -1 means current process. 774 */ 775 if (pid == -1) 776 pid = curproc->p_pid; 777 778 error = kern_kill(uap->signum, pid, uap->tid); 779 return (error); 780 } 781 782 /* 783 * Send a signal to a process group. 784 */ 785 void 786 gsignal(int pgid, int sig) 787 { 788 struct pgrp *pgrp; 789 790 if (pgid && (pgrp = pgfind(pgid))) 791 pgsignal(pgrp, sig, 0); 792 } 793 794 /* 795 * Send a signal to a process group. If checktty is 1, 796 * limit to members which have a controlling terminal. 797 * 798 * pg_lock interlocks against a fork that might be in progress, to 799 * ensure that the new child process picks up the signal. 800 */ 801 void 802 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 803 { 804 struct proc *p; 805 806 if (pgrp) { 807 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 808 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 809 if (checkctty == 0 || p->p_flag & P_CONTROLT) 810 ksignal(p, sig); 811 } 812 lockmgr(&pgrp->pg_lock, LK_RELEASE); 813 } 814 } 815 816 /* 817 * Send a signal caused by a trap to the current lwp. If it will be caught 818 * immediately, deliver it with correct code. Otherwise, post it normally. 819 * 820 * These signals may ONLY be delivered to the specified lwp and may never 821 * be delivered to the process generically. 822 */ 823 void 824 trapsignal(struct lwp *lp, int sig, u_long code) 825 { 826 struct proc *p = lp->lwp_proc; 827 struct sigacts *ps = p->p_sigacts; 828 829 /* 830 * If we are a virtual kernel running an emulated user process 831 * context, switch back to the virtual kernel context before 832 * trying to post the signal. 833 */ 834 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 835 struct trapframe *tf = lp->lwp_md.md_regs; 836 tf->tf_trapno = 0; 837 vkernel_trap(lp, tf); 838 } 839 840 841 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 842 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 843 lp->lwp_ru.ru_nsignals++; 844 #ifdef KTRACE 845 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 846 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)], 847 &lp->lwp_sigmask, code); 848 #endif 849 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 850 &lp->lwp_sigmask, code); 851 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 852 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 853 SIGADDSET(lp->lwp_sigmask, sig); 854 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 855 /* 856 * See kern_sigaction() for origin of this code. 857 */ 858 SIGDELSET(p->p_sigcatch, sig); 859 if (sig != SIGCONT && 860 sigprop(sig) & SA_IGNORE) 861 SIGADDSET(p->p_sigignore, sig); 862 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 863 } 864 } else { 865 lp->lwp_code = code; /* XXX for core dump/debugger */ 866 lp->lwp_sig = sig; /* XXX to verify code */ 867 lwpsignal(p, lp, sig); 868 } 869 } 870 871 /* 872 * Find a suitable lwp to deliver the signal to. 873 * 874 * Returns NULL if all lwps hold the signal blocked. 875 */ 876 static struct lwp * 877 find_lwp_for_signal(struct proc *p, int sig) 878 { 879 struct lwp *lp; 880 struct lwp *run, *sleep, *stop; 881 882 /* 883 * If the running/preempted thread belongs to the proc to which 884 * the signal is being delivered and this thread does not block 885 * the signal, then we can avoid a context switch by delivering 886 * the signal to this thread, because it will return to userland 887 * soon anyways. 888 */ 889 lp = lwkt_preempted_proc(); 890 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig)) 891 return (lp); 892 893 run = sleep = stop = NULL; 894 FOREACH_LWP_IN_PROC(lp, p) { 895 /* 896 * If the signal is being blocked by the lwp, then this 897 * lwp is not eligible for receiving the signal. 898 */ 899 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 900 continue; 901 902 switch (lp->lwp_stat) { 903 case LSRUN: 904 run = lp; 905 break; 906 907 case LSSTOP: 908 stop = lp; 909 break; 910 911 case LSSLEEP: 912 if (lp->lwp_flag & LWP_SINTR) 913 sleep = lp; 914 break; 915 } 916 } 917 918 if (run != NULL) 919 return (run); 920 else if (sleep != NULL) 921 return (sleep); 922 else 923 return (stop); 924 } 925 926 /* 927 * Send the signal to the process. If the signal has an action, the action 928 * is usually performed by the target process rather than the caller; we add 929 * the signal to the set of pending signals for the process. 930 * 931 * Exceptions: 932 * o When a stop signal is sent to a sleeping process that takes the 933 * default action, the process is stopped without awakening it. 934 * o SIGCONT restarts stopped processes (or puts them back to sleep) 935 * regardless of the signal action (eg, blocked or ignored). 936 * 937 * Other ignored signals are discarded immediately. 938 */ 939 void 940 ksignal(struct proc *p, int sig) 941 { 942 lwpsignal(p, NULL, sig); 943 } 944 945 /* 946 * The core for ksignal. lp may be NULL, then a suitable thread 947 * will be chosen. If not, lp MUST be a member of p. 948 */ 949 void 950 lwpsignal(struct proc *p, struct lwp *lp, int sig) 951 { 952 int prop; 953 sig_t action; 954 955 if (sig > _SIG_MAXSIG || sig <= 0) { 956 kprintf("lwpsignal: signal %d\n", sig); 957 panic("lwpsignal signal number"); 958 } 959 960 KKASSERT(lp == NULL || lp->lwp_proc == p); 961 962 crit_enter(); 963 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 964 crit_exit(); 965 966 prop = sigprop(sig); 967 968 /* 969 * If proc is traced, always give parent a chance; 970 * if signal event is tracked by procfs, give *that* 971 * a chance, as well. 972 */ 973 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 974 action = SIG_DFL; 975 } else { 976 /* 977 * Do not try to deliver signals to an exiting lwp. Note 978 * that we must still deliver the signal if P_WEXIT is set 979 * in the process flags. 980 */ 981 if (lp && (lp->lwp_flag & LWP_WEXIT)) 982 return; 983 984 /* 985 * Ig the signal is being ignored, then we forget about 986 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 987 * and if it is set to SIG_IGN, action will be SIG_DFL here. 988 */ 989 if (SIGISMEMBER(p->p_sigignore, sig)) 990 return; 991 if (SIGISMEMBER(p->p_sigcatch, sig)) 992 action = SIG_CATCH; 993 else 994 action = SIG_DFL; 995 } 996 997 /* 998 * If continuing, clear any pending STOP signals. 999 */ 1000 if (prop & SA_CONT) 1001 SIG_STOPSIGMASK(p->p_siglist); 1002 1003 if (prop & SA_STOP) { 1004 /* 1005 * If sending a tty stop signal to a member of an orphaned 1006 * process group, discard the signal here if the action 1007 * is default; don't stop the process below if sleeping, 1008 * and don't clear any pending SIGCONT. 1009 */ 1010 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1011 action == SIG_DFL) { 1012 return; 1013 } 1014 SIG_CONTSIGMASK(p->p_siglist); 1015 } 1016 1017 crit_enter(); 1018 1019 if (p->p_stat == SSTOP) { 1020 /* 1021 * Nobody can handle this signal, add it to the lwp or 1022 * process pending list 1023 */ 1024 if (lp) 1025 SIGADDSET(lp->lwp_siglist, sig); 1026 else 1027 SIGADDSET(p->p_siglist, sig); 1028 1029 /* 1030 * If the process is stopped and is being traced, then no 1031 * further action is necessary. 1032 */ 1033 if (p->p_flag & P_TRACED) 1034 goto out; 1035 1036 /* 1037 * If the process is stopped and receives a KILL signal, 1038 * make the process runnable. 1039 */ 1040 if (sig == SIGKILL) { 1041 proc_unstop(p); 1042 goto active_process; 1043 } 1044 1045 /* 1046 * If the process is stopped and receives a CONT signal, 1047 * then try to make the process runnable again. 1048 */ 1049 if (prop & SA_CONT) { 1050 /* 1051 * If SIGCONT is default (or ignored), we continue the 1052 * process but don't leave the signal in p_siglist, as 1053 * it has no further action. If SIGCONT is held, we 1054 * continue the process and leave the signal in 1055 * p_siglist. If the process catches SIGCONT, let it 1056 * handle the signal itself. 1057 */ 1058 /* XXX what if the signal is being held blocked? */ 1059 if (action == SIG_DFL) 1060 SIGDELSET(p->p_siglist, sig); 1061 proc_unstop(p); 1062 if (action == SIG_CATCH) 1063 goto active_process; 1064 goto out; 1065 } 1066 1067 /* 1068 * If the process is stopped and receives another STOP 1069 * signal, we do not need to stop it again. If we did 1070 * the shell could get confused. 1071 * 1072 * However, if the current/preempted lwp is part of the 1073 * process receiving the signal, we need to keep it, 1074 * so that this lwp can stop in issignal() later, as 1075 * we don't want to wait until it reaches userret! 1076 */ 1077 if (prop & SA_STOP) { 1078 if (lwkt_preempted_proc() == NULL || 1079 lwkt_preempted_proc()->lwp_proc != p) 1080 SIGDELSET(p->p_siglist, sig); 1081 } 1082 1083 /* 1084 * Otherwise the process is stopped and it received some 1085 * signal, which does not change its stopped state. 1086 * 1087 * We have to select one thread to set LWP_BREAKTSLEEP, 1088 * so that the current signal will break the sleep 1089 * as soon as a SA_CONT signal will unstop the process. 1090 */ 1091 if (lp == NULL) 1092 lp = find_lwp_for_signal(p, sig); 1093 if (lp != NULL && 1094 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1095 lp->lwp_flag |= LWP_BREAKTSLEEP; 1096 goto out; 1097 1098 /* NOTREACHED */ 1099 } 1100 /* else not stopped */ 1101 active_process: 1102 1103 /* 1104 * Never deliver a lwp-specific signal to a random lwp. 1105 */ 1106 if (lp == NULL) { 1107 lp = find_lwp_for_signal(p, sig); 1108 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1109 lp = NULL; 1110 } 1111 1112 /* 1113 * Deliver to the process generically if (1) the signal is being 1114 * sent to any thread or (2) we could not find a thread to deliver 1115 * it to. 1116 */ 1117 if (lp == NULL) { 1118 SIGADDSET(p->p_siglist, sig); 1119 goto out; 1120 } 1121 1122 /* 1123 * Deliver to a specific LWP whether it masks it or not. It will 1124 * not be dispatched if masked but we must still deliver it. 1125 */ 1126 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1127 (p->p_flag & P_TRACED) == 0) { 1128 p->p_nice = NZERO; 1129 } 1130 1131 /* 1132 * If the process receives a STOP signal which indeed needs to 1133 * stop the process, do so. If the process chose to catch the 1134 * signal, it will be treated like any other signal. 1135 */ 1136 if ((prop & SA_STOP) && action == SIG_DFL) { 1137 /* 1138 * If a child holding parent blocked, stopping 1139 * could cause deadlock. Take no action at this 1140 * time. 1141 */ 1142 if (p->p_flag & P_PPWAIT) { 1143 SIGADDSET(p->p_siglist, sig); 1144 goto out; 1145 } 1146 1147 /* 1148 * Do not actually try to manipulate the process, but simply 1149 * stop it. Lwps will stop as soon as they safely can. 1150 */ 1151 p->p_xstat = sig; 1152 proc_stop(p); 1153 goto out; 1154 } 1155 1156 /* 1157 * If it is a CONT signal with default action, just ignore it. 1158 */ 1159 if ((prop & SA_CONT) && action == SIG_DFL) 1160 goto out; 1161 1162 /* 1163 * Mark signal pending at this specific thread. 1164 */ 1165 SIGADDSET(lp->lwp_siglist, sig); 1166 1167 lwp_signotify(lp); 1168 1169 out: 1170 crit_exit(); 1171 } 1172 1173 void 1174 lwp_signotify(struct lwp *lp) 1175 { 1176 crit_enter(); 1177 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1178 /* 1179 * Thread is in tsleep. 1180 */ 1181 1182 /* 1183 * If the thread is sleeping uninterruptibly 1184 * we can't interrupt the sleep... the signal will 1185 * be noticed when the lwp returns through 1186 * trap() or syscall(). 1187 * 1188 * Otherwise the signal can interrupt the sleep. 1189 * 1190 * If the process is traced, the lwp will handle the 1191 * tracing in issignal() when it returns to userland. 1192 */ 1193 if (lp->lwp_flag & LWP_SINTR) { 1194 /* 1195 * Make runnable and break out of any tsleep as well. 1196 */ 1197 lp->lwp_flag |= LWP_BREAKTSLEEP; 1198 setrunnable(lp); 1199 } 1200 } else { 1201 /* 1202 * Otherwise the thread is running 1203 * 1204 * LSRUN does nothing with the signal, other than kicking 1205 * ourselves if we are running. 1206 * SZOMB and SIDL mean that it will either never be noticed, 1207 * or noticed very soon. 1208 * 1209 * Note that lwp_thread may be NULL or may not be completely 1210 * initialized if the process is in the SIDL or SZOMB state. 1211 * 1212 * For SMP we may have to forward the request to another cpu. 1213 * YYY the MP lock prevents the target process from moving 1214 * to another cpu, see kern/kern_switch.c 1215 * 1216 * If the target thread is waiting on its message port, 1217 * wakeup the target thread so it can check (or ignore) 1218 * the new signal. YYY needs cleanup. 1219 */ 1220 if (lp == lwkt_preempted_proc()) { 1221 signotify(); 1222 } else if (lp->lwp_stat == LSRUN) { 1223 struct thread *td = lp->lwp_thread; 1224 struct proc *p = lp->lwp_proc; 1225 1226 KASSERT(td != NULL, 1227 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1228 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1229 p->p_flag, lp->lwp_flag)); 1230 1231 /* 1232 * To prevent a MP race with TDF_SINTR we must 1233 * schedule the thread on the correct cpu. 1234 */ 1235 #ifdef SMP 1236 if (td->td_gd != mycpu) 1237 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1238 else 1239 #endif 1240 if (td->td_flags & TDF_SINTR) 1241 lwkt_schedule(td); 1242 } 1243 } 1244 crit_exit(); 1245 } 1246 1247 #ifdef SMP 1248 1249 /* 1250 * This function is called via an IPI. We will be in a critical section but 1251 * the MP lock will NOT be held. Also note that by the time the ipi message 1252 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1253 */ 1254 static void 1255 signotify_remote(void *arg) 1256 { 1257 struct lwp *lp = arg; 1258 1259 if (lp == lwkt_preempted_proc()) { 1260 signotify(); 1261 } else { 1262 struct thread *td = lp->lwp_thread; 1263 if (td->td_flags & TDF_SINTR) 1264 lwkt_schedule(td); 1265 } 1266 } 1267 1268 #endif 1269 1270 void 1271 proc_stop(struct proc *p) 1272 { 1273 struct lwp *lp; 1274 1275 /* If somebody raced us, be happy with it */ 1276 if (p->p_stat == SSTOP) 1277 return; 1278 1279 crit_enter(); 1280 p->p_stat = SSTOP; 1281 1282 FOREACH_LWP_IN_PROC(lp, p) { 1283 switch (lp->lwp_stat) { 1284 case LSSTOP: 1285 /* 1286 * Do nothing, we are already counted in 1287 * p_nstopped. 1288 */ 1289 break; 1290 1291 case LSSLEEP: 1292 /* 1293 * We're sleeping, but we will stop before 1294 * returning to userspace, so count us 1295 * as stopped as well. We set LWP_WSTOP 1296 * to signal the lwp that it should not 1297 * increase p_nstopped when reaching tstop(). 1298 */ 1299 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1300 lp->lwp_flag |= LWP_WSTOP; 1301 ++p->p_nstopped; 1302 } 1303 break; 1304 1305 case LSRUN: 1306 /* 1307 * We might notify ourself, but that's not 1308 * a problem. 1309 */ 1310 lwp_signotify(lp); 1311 break; 1312 } 1313 } 1314 1315 if (p->p_nstopped == p->p_nthreads) { 1316 p->p_flag &= ~P_WAITED; 1317 wakeup(p->p_pptr); 1318 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1319 ksignal(p->p_pptr, SIGCHLD); 1320 } 1321 crit_exit(); 1322 } 1323 1324 void 1325 proc_unstop(struct proc *p) 1326 { 1327 struct lwp *lp; 1328 1329 if (p->p_stat != SSTOP) 1330 return; 1331 1332 crit_enter(); 1333 p->p_stat = SACTIVE; 1334 1335 FOREACH_LWP_IN_PROC(lp, p) { 1336 switch (lp->lwp_stat) { 1337 case LSRUN: 1338 /* 1339 * Uh? Not stopped? Well, I guess that's okay. 1340 */ 1341 if (bootverbose) 1342 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1343 p->p_pid, lp->lwp_tid); 1344 break; 1345 1346 case LSSLEEP: 1347 /* 1348 * Still sleeping. Don't bother waking it up. 1349 * However, if this thread was counted as 1350 * stopped, undo this. 1351 * 1352 * Nevertheless we call setrunnable() so that it 1353 * will wake up in case a signal or timeout arrived 1354 * in the meantime. 1355 */ 1356 if (lp->lwp_flag & LWP_WSTOP) { 1357 --p->p_nstopped; 1358 } else { 1359 if (bootverbose) 1360 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1361 p->p_pid, lp->lwp_tid); 1362 } 1363 /* FALLTHROUGH */ 1364 1365 case LSSTOP: 1366 setrunnable(lp); 1367 break; 1368 1369 } 1370 lp->lwp_flag &= ~LWP_WSTOP; 1371 } 1372 crit_exit(); 1373 } 1374 1375 static int 1376 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1377 { 1378 sigset_t savedmask, set; 1379 struct proc *p = curproc; 1380 struct lwp *lp = curthread->td_lwp; 1381 int error, sig, hz, timevalid = 0; 1382 struct timespec rts, ets, ts; 1383 struct timeval tv; 1384 1385 error = 0; 1386 sig = 0; 1387 SIG_CANTMASK(waitset); 1388 savedmask = lp->lwp_sigmask; 1389 1390 if (timeout) { 1391 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1392 timeout->tv_nsec < 1000000000) { 1393 timevalid = 1; 1394 getnanouptime(&rts); 1395 ets = rts; 1396 timespecadd(&ets, timeout); 1397 } 1398 } 1399 1400 for (;;) { 1401 set = lwp_sigpend(lp); 1402 SIGSETAND(set, waitset); 1403 if ((sig = sig_ffs(&set)) != 0) { 1404 SIGFILLSET(lp->lwp_sigmask); 1405 SIGDELSET(lp->lwp_sigmask, sig); 1406 SIG_CANTMASK(lp->lwp_sigmask); 1407 sig = issignal(lp); 1408 /* 1409 * It may be a STOP signal, in the case, issignal 1410 * returns 0, because we may stop there, and new 1411 * signal can come in, we should restart if we got 1412 * nothing. 1413 */ 1414 if (sig == 0) 1415 continue; 1416 else 1417 break; 1418 } 1419 1420 /* 1421 * Previous checking got nothing, and we retried but still 1422 * got nothing, we should return the error status. 1423 */ 1424 if (error) 1425 break; 1426 1427 /* 1428 * POSIX says this must be checked after looking for pending 1429 * signals. 1430 */ 1431 if (timeout) { 1432 if (!timevalid) { 1433 error = EINVAL; 1434 break; 1435 } 1436 getnanouptime(&rts); 1437 if (timespeccmp(&rts, &ets, >=)) { 1438 error = EAGAIN; 1439 break; 1440 } 1441 ts = ets; 1442 timespecsub(&ts, &rts); 1443 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1444 hz = tvtohz_high(&tv); 1445 } else 1446 hz = 0; 1447 1448 lp->lwp_sigmask = savedmask; 1449 SIGSETNAND(lp->lwp_sigmask, waitset); 1450 /* 1451 * We won't ever be woken up. Instead, our sleep will 1452 * be broken in lwpsignal(). 1453 */ 1454 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1455 if (timeout) { 1456 if (error == ERESTART) { 1457 /* can not restart a timeout wait. */ 1458 error = EINTR; 1459 } else if (error == EAGAIN) { 1460 /* will calculate timeout by ourself. */ 1461 error = 0; 1462 } 1463 } 1464 /* Retry ... */ 1465 } 1466 1467 lp->lwp_sigmask = savedmask; 1468 if (sig) { 1469 error = 0; 1470 bzero(info, sizeof(*info)); 1471 info->si_signo = sig; 1472 lwp_delsig(lp, sig); /* take the signal! */ 1473 1474 if (sig == SIGKILL) 1475 sigexit(p, sig); 1476 } 1477 return (error); 1478 } 1479 1480 int 1481 sys_sigtimedwait(struct sigtimedwait_args *uap) 1482 { 1483 struct timespec ts; 1484 struct timespec *timeout; 1485 sigset_t set; 1486 siginfo_t info; 1487 int error; 1488 1489 if (uap->timeout) { 1490 error = copyin(uap->timeout, &ts, sizeof(ts)); 1491 if (error) 1492 return (error); 1493 timeout = &ts; 1494 } else { 1495 timeout = NULL; 1496 } 1497 error = copyin(uap->set, &set, sizeof(set)); 1498 if (error) 1499 return (error); 1500 error = kern_sigtimedwait(set, &info, timeout); 1501 if (error) 1502 return (error); 1503 if (uap->info) 1504 error = copyout(&info, uap->info, sizeof(info)); 1505 /* Repost if we got an error. */ 1506 /* 1507 * XXX lwp 1508 * 1509 * This could transform a thread-specific signal to another 1510 * thread / process pending signal. 1511 */ 1512 if (error) 1513 ksignal(curproc, info.si_signo); 1514 else 1515 uap->sysmsg_result = info.si_signo; 1516 return (error); 1517 } 1518 1519 int 1520 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1521 { 1522 siginfo_t info; 1523 sigset_t set; 1524 int error; 1525 1526 error = copyin(uap->set, &set, sizeof(set)); 1527 if (error) 1528 return (error); 1529 error = kern_sigtimedwait(set, &info, NULL); 1530 if (error) 1531 return (error); 1532 if (uap->info) 1533 error = copyout(&info, uap->info, sizeof(info)); 1534 /* Repost if we got an error. */ 1535 /* 1536 * XXX lwp 1537 * 1538 * This could transform a thread-specific signal to another 1539 * thread / process pending signal. 1540 */ 1541 if (error) 1542 ksignal(curproc, info.si_signo); 1543 else 1544 uap->sysmsg_result = info.si_signo; 1545 return (error); 1546 } 1547 1548 /* 1549 * If the current process has received a signal that would interrupt a 1550 * system call, return EINTR or ERESTART as appropriate. 1551 */ 1552 int 1553 iscaught(struct lwp *lp) 1554 { 1555 struct proc *p = lp->lwp_proc; 1556 int sig; 1557 1558 if (p) { 1559 if ((sig = CURSIG(lp)) != 0) { 1560 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1561 return (EINTR); 1562 return (ERESTART); 1563 } 1564 } 1565 return(EWOULDBLOCK); 1566 } 1567 1568 /* 1569 * If the current process has received a signal (should be caught or cause 1570 * termination, should interrupt current syscall), return the signal number. 1571 * Stop signals with default action are processed immediately, then cleared; 1572 * they aren't returned. This is checked after each entry to the system for 1573 * a syscall or trap (though this can usually be done without calling issignal 1574 * by checking the pending signal masks in the CURSIG macro.) The normal call 1575 * sequence is 1576 * 1577 * This routine is called via CURSIG/__cursig and the MP lock might not be 1578 * held. Obtain the MP lock for the duration of the operation. 1579 * 1580 * while (sig = CURSIG(curproc)) 1581 * postsig(sig); 1582 */ 1583 int 1584 issignal(struct lwp *lp) 1585 { 1586 struct proc *p = lp->lwp_proc; 1587 sigset_t mask; 1588 int sig, prop; 1589 1590 get_mplock(); 1591 for (;;) { 1592 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1593 1594 mask = lwp_sigpend(lp); 1595 SIGSETNAND(mask, lp->lwp_sigmask); 1596 if (p->p_flag & P_PPWAIT) 1597 SIG_STOPSIGMASK(mask); 1598 if (SIGISEMPTY(mask)) { /* no signal to send */ 1599 rel_mplock(); 1600 return (0); 1601 } 1602 sig = sig_ffs(&mask); 1603 1604 STOPEVENT(p, S_SIG, sig); 1605 1606 /* 1607 * We should see pending but ignored signals 1608 * only if P_TRACED was on when they were posted. 1609 */ 1610 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1611 lwp_delsig(lp, sig); 1612 continue; 1613 } 1614 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1615 /* 1616 * If traced, always stop, and stay stopped until 1617 * released by the parent. 1618 * 1619 * NOTE: SSTOP may get cleared during the loop, 1620 * but we do not re-notify the parent if we have 1621 * to loop several times waiting for the parent 1622 * to let us continue. 1623 * 1624 * XXX not sure if this is still true 1625 */ 1626 p->p_xstat = sig; 1627 proc_stop(p); 1628 do { 1629 tstop(); 1630 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1631 1632 /* 1633 * If parent wants us to take the signal, 1634 * then it will leave it in p->p_xstat; 1635 * otherwise we just look for signals again. 1636 */ 1637 lwp_delsig(lp, sig); /* clear old signal */ 1638 sig = p->p_xstat; 1639 if (sig == 0) 1640 continue; 1641 1642 /* 1643 * Put the new signal into p_siglist. If the 1644 * signal is being masked, look for other signals. 1645 * 1646 * XXX lwp might need a call to ksignal() 1647 */ 1648 SIGADDSET(p->p_siglist, sig); 1649 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1650 continue; 1651 1652 /* 1653 * If the traced bit got turned off, go back up 1654 * to the top to rescan signals. This ensures 1655 * that p_sig* and ps_sigact are consistent. 1656 */ 1657 if ((p->p_flag & P_TRACED) == 0) 1658 continue; 1659 } 1660 1661 prop = sigprop(sig); 1662 1663 /* 1664 * Decide whether the signal should be returned. 1665 * Return the signal's number, or fall through 1666 * to clear it from the pending mask. 1667 */ 1668 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1669 case (int)SIG_DFL: 1670 /* 1671 * Don't take default actions on system processes. 1672 */ 1673 if (p->p_pid <= 1) { 1674 #ifdef DIAGNOSTIC 1675 /* 1676 * Are you sure you want to ignore SIGSEGV 1677 * in init? XXX 1678 */ 1679 kprintf("Process (pid %lu) got signal %d\n", 1680 (u_long)p->p_pid, sig); 1681 #endif 1682 break; /* == ignore */ 1683 } 1684 1685 /* 1686 * Handle the in-kernel checkpoint action 1687 */ 1688 if (prop & SA_CKPT) { 1689 checkpoint_signal_handler(lp); 1690 break; 1691 } 1692 1693 /* 1694 * If there is a pending stop signal to process 1695 * with default action, stop here, 1696 * then clear the signal. However, 1697 * if process is member of an orphaned 1698 * process group, ignore tty stop signals. 1699 */ 1700 if (prop & SA_STOP) { 1701 if (p->p_flag & P_TRACED || 1702 (p->p_pgrp->pg_jobc == 0 && 1703 prop & SA_TTYSTOP)) 1704 break; /* == ignore */ 1705 p->p_xstat = sig; 1706 proc_stop(p); 1707 while (p->p_stat == SSTOP) { 1708 tstop(); 1709 } 1710 break; 1711 } else if (prop & SA_IGNORE) { 1712 /* 1713 * Except for SIGCONT, shouldn't get here. 1714 * Default action is to ignore; drop it. 1715 */ 1716 break; /* == ignore */ 1717 } else { 1718 rel_mplock(); 1719 return (sig); 1720 } 1721 1722 /*NOTREACHED*/ 1723 1724 case (int)SIG_IGN: 1725 /* 1726 * Masking above should prevent us ever trying 1727 * to take action on an ignored signal other 1728 * than SIGCONT, unless process is traced. 1729 */ 1730 if ((prop & SA_CONT) == 0 && 1731 (p->p_flag & P_TRACED) == 0) 1732 kprintf("issignal\n"); 1733 break; /* == ignore */ 1734 1735 default: 1736 /* 1737 * This signal has an action, let 1738 * postsig() process it. 1739 */ 1740 rel_mplock(); 1741 return (sig); 1742 } 1743 lwp_delsig(lp, sig); /* take the signal! */ 1744 } 1745 /* NOTREACHED */ 1746 } 1747 1748 /* 1749 * Take the action for the specified signal 1750 * from the current set of pending signals. 1751 */ 1752 void 1753 postsig(int sig) 1754 { 1755 struct lwp *lp = curthread->td_lwp; 1756 struct proc *p = lp->lwp_proc; 1757 struct sigacts *ps = p->p_sigacts; 1758 sig_t action; 1759 sigset_t returnmask; 1760 int code; 1761 1762 KASSERT(sig != 0, ("postsig")); 1763 1764 /* 1765 * If we are a virtual kernel running an emulated user process 1766 * context, switch back to the virtual kernel context before 1767 * trying to post the signal. 1768 */ 1769 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1770 struct trapframe *tf = lp->lwp_md.md_regs; 1771 tf->tf_trapno = 0; 1772 vkernel_trap(lp, tf); 1773 } 1774 1775 lwp_delsig(lp, sig); 1776 action = ps->ps_sigact[_SIG_IDX(sig)]; 1777 #ifdef KTRACE 1778 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1779 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1780 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1781 #endif 1782 STOPEVENT(p, S_SIG, sig); 1783 1784 if (action == SIG_DFL) { 1785 /* 1786 * Default action, where the default is to kill 1787 * the process. (Other cases were ignored above.) 1788 */ 1789 sigexit(p, sig); 1790 /* NOTREACHED */ 1791 } else { 1792 /* 1793 * If we get here, the signal must be caught. 1794 */ 1795 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1796 ("postsig action")); 1797 1798 crit_enter(); 1799 1800 /* 1801 * Reset the signal handler if asked to 1802 */ 1803 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1804 /* 1805 * See kern_sigaction() for origin of this code. 1806 */ 1807 SIGDELSET(p->p_sigcatch, sig); 1808 if (sig != SIGCONT && 1809 sigprop(sig) & SA_IGNORE) 1810 SIGADDSET(p->p_sigignore, sig); 1811 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1812 } 1813 1814 /* 1815 * Handle the mailbox case. Copyout to the appropriate 1816 * location but do not generate a signal frame. The system 1817 * call simply returns EINTR and the user is responsible for 1818 * polling the mailbox. 1819 */ 1820 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1821 int sig_copy = sig; 1822 copyout(&sig_copy, (void *)action, sizeof(int)); 1823 curproc->p_flag |= P_MAILBOX; 1824 crit_exit(); 1825 goto done; 1826 } 1827 1828 /* 1829 * Set the signal mask and calculate the mask to restore 1830 * when the signal function returns. 1831 * 1832 * Special case: user has done a sigsuspend. Here the 1833 * current mask is not of interest, but rather the 1834 * mask from before the sigsuspend is what we want 1835 * restored after the signal processing is completed. 1836 */ 1837 if (lp->lwp_flag & LWP_OLDMASK) { 1838 returnmask = lp->lwp_oldsigmask; 1839 lp->lwp_flag &= ~LWP_OLDMASK; 1840 } else { 1841 returnmask = lp->lwp_sigmask; 1842 } 1843 1844 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1845 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1846 SIGADDSET(lp->lwp_sigmask, sig); 1847 1848 crit_exit(); 1849 lp->lwp_ru.ru_nsignals++; 1850 if (lp->lwp_sig != sig) { 1851 code = 0; 1852 } else { 1853 code = lp->lwp_code; 1854 lp->lwp_code = 0; 1855 lp->lwp_sig = 0; 1856 } 1857 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1858 } 1859 done: 1860 ; 1861 } 1862 1863 /* 1864 * Kill the current process for stated reason. 1865 */ 1866 void 1867 killproc(struct proc *p, char *why) 1868 { 1869 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1870 p->p_pid, p->p_comm, 1871 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1872 ksignal(p, SIGKILL); 1873 } 1874 1875 /* 1876 * Force the current process to exit with the specified signal, dumping core 1877 * if appropriate. We bypass the normal tests for masked and caught signals, 1878 * allowing unrecoverable failures to terminate the process without changing 1879 * signal state. Mark the accounting record with the signal termination. 1880 * If dumping core, save the signal number for the debugger. Calls exit and 1881 * does not return. 1882 */ 1883 void 1884 sigexit(struct proc *p, int sig) 1885 { 1886 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */ 1887 1888 p->p_acflag |= AXSIG; 1889 if (sigprop(sig) & SA_CORE) { 1890 lp->lwp_sig = sig; 1891 /* 1892 * Log signals which would cause core dumps 1893 * (Log as LOG_INFO to appease those who don't want 1894 * these messages.) 1895 * XXX : Todo, as well as euid, write out ruid too 1896 */ 1897 if (coredump(lp, sig) == 0) 1898 sig |= WCOREFLAG; 1899 if (kern_logsigexit) 1900 log(LOG_INFO, 1901 "pid %d (%s), uid %d: exited on signal %d%s\n", 1902 p->p_pid, p->p_comm, 1903 p->p_ucred ? p->p_ucred->cr_uid : -1, 1904 sig &~ WCOREFLAG, 1905 sig & WCOREFLAG ? " (core dumped)" : ""); 1906 } 1907 exit1(W_EXITCODE(0, sig)); 1908 /* NOTREACHED */ 1909 } 1910 1911 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1912 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1913 sizeof(corefilename), "process corefile name format string"); 1914 1915 /* 1916 * expand_name(name, uid, pid) 1917 * Expand the name described in corefilename, using name, uid, and pid. 1918 * corefilename is a kprintf-like string, with three format specifiers: 1919 * %N name of process ("name") 1920 * %P process id (pid) 1921 * %U user id (uid) 1922 * For example, "%N.core" is the default; they can be disabled completely 1923 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1924 * This is controlled by the sysctl variable kern.corefile (see above). 1925 */ 1926 1927 static char * 1928 expand_name(const char *name, uid_t uid, pid_t pid) 1929 { 1930 char *temp; 1931 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1932 int i, n; 1933 char *format = corefilename; 1934 size_t namelen; 1935 1936 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1937 if (temp == NULL) 1938 return NULL; 1939 namelen = strlen(name); 1940 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1941 int l; 1942 switch (format[i]) { 1943 case '%': /* Format character */ 1944 i++; 1945 switch (format[i]) { 1946 case '%': 1947 temp[n++] = '%'; 1948 break; 1949 case 'N': /* process name */ 1950 if ((n + namelen) > 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, name, namelen); 1957 n += namelen; 1958 break; 1959 case 'P': /* process id */ 1960 l = ksprintf(buf, "%u", pid); 1961 if ((n + l) > MAXPATHLEN) { 1962 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1963 pid, name, uid, temp, name); 1964 kfree(temp, M_TEMP); 1965 return NULL; 1966 } 1967 memcpy(temp+n, buf, l); 1968 n += l; 1969 break; 1970 case 'U': /* user id */ 1971 l = ksprintf(buf, "%u", uid); 1972 if ((n + l) > MAXPATHLEN) { 1973 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1974 pid, name, uid, temp, name); 1975 kfree(temp, M_TEMP); 1976 return NULL; 1977 } 1978 memcpy(temp+n, buf, l); 1979 n += l; 1980 break; 1981 default: 1982 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1983 } 1984 break; 1985 default: 1986 temp[n++] = format[i]; 1987 } 1988 } 1989 temp[n] = '\0'; 1990 return temp; 1991 } 1992 1993 /* 1994 * Dump a process' core. The main routine does some 1995 * policy checking, and creates the name of the coredump; 1996 * then it passes on a vnode and a size limit to the process-specific 1997 * coredump routine if there is one; if there _is not_ one, it returns 1998 * ENOSYS; otherwise it returns the error from the process-specific routine. 1999 * 2000 * The parameter `lp' is the lwp which triggered the coredump. 2001 */ 2002 2003 static int 2004 coredump(struct lwp *lp, int sig) 2005 { 2006 struct proc *p = lp->lwp_proc; 2007 struct vnode *vp; 2008 struct ucred *cred = p->p_ucred; 2009 struct flock lf; 2010 struct nlookupdata nd; 2011 struct vattr vattr; 2012 int error, error1; 2013 char *name; /* name of corefile */ 2014 off_t limit; 2015 2016 STOPEVENT(p, S_CORE, 0); 2017 2018 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2019 return (EFAULT); 2020 2021 /* 2022 * Note that the bulk of limit checking is done after 2023 * the corefile is created. The exception is if the limit 2024 * for corefiles is 0, in which case we don't bother 2025 * creating the corefile at all. This layout means that 2026 * a corefile is truncated instead of not being created, 2027 * if it is larger than the limit. 2028 */ 2029 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2030 if (limit == 0) 2031 return EFBIG; 2032 2033 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2034 if (name == NULL) 2035 return (EINVAL); 2036 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2037 if (error == 0) 2038 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2039 kfree(name, M_TEMP); 2040 if (error) { 2041 nlookup_done(&nd); 2042 return (error); 2043 } 2044 vp = nd.nl_open_vp; 2045 nd.nl_open_vp = NULL; 2046 nlookup_done(&nd); 2047 2048 vn_unlock(vp); 2049 lf.l_whence = SEEK_SET; 2050 lf.l_start = 0; 2051 lf.l_len = 0; 2052 lf.l_type = F_WRLCK; 2053 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2054 if (error) 2055 goto out2; 2056 2057 /* Don't dump to non-regular files or files with links. */ 2058 if (vp->v_type != VREG || 2059 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2060 error = EFAULT; 2061 goto out1; 2062 } 2063 2064 VATTR_NULL(&vattr); 2065 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2066 vattr.va_size = 0; 2067 VOP_SETATTR(vp, &vattr, cred); 2068 p->p_acflag |= ACORE; 2069 vn_unlock(vp); 2070 2071 error = p->p_sysent->sv_coredump ? 2072 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2073 2074 out1: 2075 lf.l_type = F_UNLCK; 2076 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2077 out2: 2078 error1 = vn_close(vp, FWRITE); 2079 if (error == 0) 2080 error = error1; 2081 return (error); 2082 } 2083 2084 /* 2085 * Nonexistent system call-- signal process (may want to handle it). 2086 * Flag error in case process won't see signal immediately (blocked or ignored). 2087 */ 2088 /* ARGSUSED */ 2089 int 2090 sys_nosys(struct nosys_args *args) 2091 { 2092 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2093 return (EINVAL); 2094 } 2095 2096 /* 2097 * Send a SIGIO or SIGURG signal to a process or process group using 2098 * stored credentials rather than those of the current process. 2099 */ 2100 void 2101 pgsigio(struct sigio *sigio, int sig, int checkctty) 2102 { 2103 if (sigio == NULL) 2104 return; 2105 2106 if (sigio->sio_pgid > 0) { 2107 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2108 sigio->sio_proc)) 2109 ksignal(sigio->sio_proc, sig); 2110 } else if (sigio->sio_pgid < 0) { 2111 struct proc *p; 2112 2113 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2114 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2115 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2116 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2117 ksignal(p, sig); 2118 } 2119 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2120 } 2121 } 2122 2123 static int 2124 filt_sigattach(struct knote *kn) 2125 { 2126 struct proc *p = curproc; 2127 2128 kn->kn_ptr.p_proc = p; 2129 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2130 2131 /* XXX lock the proc here while adding to the list? */ 2132 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2133 2134 return (0); 2135 } 2136 2137 static void 2138 filt_sigdetach(struct knote *kn) 2139 { 2140 struct proc *p = kn->kn_ptr.p_proc; 2141 2142 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2143 } 2144 2145 /* 2146 * signal knotes are shared with proc knotes, so we apply a mask to 2147 * the hint in order to differentiate them from process hints. This 2148 * could be avoided by using a signal-specific knote list, but probably 2149 * isn't worth the trouble. 2150 */ 2151 static int 2152 filt_signal(struct knote *kn, long hint) 2153 { 2154 if (hint & NOTE_SIGNAL) { 2155 hint &= ~NOTE_SIGNAL; 2156 2157 if (kn->kn_id == hint) 2158 kn->kn_data++; 2159 } 2160 return (kn->kn_data != 0); 2161 } 2162