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 1.89 2008/04/21 15:47:54 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(lp, 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 p->p_flag &= ~P_CONTINUED; 1016 } 1017 1018 crit_enter(); 1019 1020 if (p->p_stat == SSTOP) { 1021 /* 1022 * Nobody can handle this signal, add it to the lwp or 1023 * process pending list 1024 */ 1025 if (lp) 1026 SIGADDSET(lp->lwp_siglist, sig); 1027 else 1028 SIGADDSET(p->p_siglist, sig); 1029 1030 /* 1031 * If the process is stopped and is being traced, then no 1032 * further action is necessary. 1033 */ 1034 if (p->p_flag & P_TRACED) 1035 goto out; 1036 1037 /* 1038 * If the process is stopped and receives a KILL signal, 1039 * make the process runnable. 1040 */ 1041 if (sig == SIGKILL) { 1042 proc_unstop(p); 1043 goto active_process; 1044 } 1045 1046 /* 1047 * If the process is stopped and receives a CONT signal, 1048 * then try to make the process runnable again. 1049 */ 1050 if (prop & SA_CONT) { 1051 /* 1052 * If SIGCONT is default (or ignored), we continue the 1053 * process but don't leave the signal in p_siglist, as 1054 * it has no further action. If SIGCONT is held, we 1055 * continue the process and leave the signal in 1056 * p_siglist. If the process catches SIGCONT, let it 1057 * handle the signal itself. 1058 */ 1059 /* XXX what if the signal is being held blocked? */ 1060 p->p_flag |= P_CONTINUED; 1061 wakeup(p->p_pptr); 1062 if (action == SIG_DFL) 1063 SIGDELSET(p->p_siglist, sig); 1064 proc_unstop(p); 1065 if (action == SIG_CATCH) 1066 goto active_process; 1067 goto out; 1068 } 1069 1070 /* 1071 * If the process is stopped and receives another STOP 1072 * signal, we do not need to stop it again. If we did 1073 * the shell could get confused. 1074 * 1075 * However, if the current/preempted lwp is part of the 1076 * process receiving the signal, we need to keep it, 1077 * so that this lwp can stop in issignal() later, as 1078 * we don't want to wait until it reaches userret! 1079 */ 1080 if (prop & SA_STOP) { 1081 if (lwkt_preempted_proc() == NULL || 1082 lwkt_preempted_proc()->lwp_proc != p) 1083 SIGDELSET(p->p_siglist, sig); 1084 } 1085 1086 /* 1087 * Otherwise the process is stopped and it received some 1088 * signal, which does not change its stopped state. 1089 * 1090 * We have to select one thread to set LWP_BREAKTSLEEP, 1091 * so that the current signal will break the sleep 1092 * as soon as a SA_CONT signal will unstop the process. 1093 */ 1094 if (lp == NULL) 1095 lp = find_lwp_for_signal(p, sig); 1096 if (lp != NULL && 1097 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1098 lp->lwp_flag |= LWP_BREAKTSLEEP; 1099 goto out; 1100 1101 /* NOTREACHED */ 1102 } 1103 /* else not stopped */ 1104 active_process: 1105 1106 /* 1107 * Never deliver a lwp-specific signal to a random lwp. 1108 */ 1109 if (lp == NULL) { 1110 lp = find_lwp_for_signal(p, sig); 1111 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1112 lp = NULL; 1113 } 1114 1115 /* 1116 * Deliver to the process generically if (1) the signal is being 1117 * sent to any thread or (2) we could not find a thread to deliver 1118 * it to. 1119 */ 1120 if (lp == NULL) { 1121 SIGADDSET(p->p_siglist, sig); 1122 goto out; 1123 } 1124 1125 /* 1126 * Deliver to a specific LWP whether it masks it or not. It will 1127 * not be dispatched if masked but we must still deliver it. 1128 */ 1129 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1130 (p->p_flag & P_TRACED) == 0) { 1131 p->p_nice = NZERO; 1132 } 1133 1134 /* 1135 * If the process receives a STOP signal which indeed needs to 1136 * stop the process, do so. If the process chose to catch the 1137 * signal, it will be treated like any other signal. 1138 */ 1139 if ((prop & SA_STOP) && action == SIG_DFL) { 1140 /* 1141 * If a child holding parent blocked, stopping 1142 * could cause deadlock. Take no action at this 1143 * time. 1144 */ 1145 if (p->p_flag & P_PPWAIT) { 1146 SIGADDSET(p->p_siglist, sig); 1147 goto out; 1148 } 1149 1150 /* 1151 * Do not actually try to manipulate the process, but simply 1152 * stop it. Lwps will stop as soon as they safely can. 1153 */ 1154 p->p_xstat = sig; 1155 proc_stop(p); 1156 goto out; 1157 } 1158 1159 /* 1160 * If it is a CONT signal with default action, just ignore it. 1161 */ 1162 if ((prop & SA_CONT) && action == SIG_DFL) 1163 goto out; 1164 1165 /* 1166 * Mark signal pending at this specific thread. 1167 */ 1168 SIGADDSET(lp->lwp_siglist, sig); 1169 1170 lwp_signotify(lp); 1171 1172 out: 1173 crit_exit(); 1174 } 1175 1176 void 1177 lwp_signotify(struct lwp *lp) 1178 { 1179 crit_enter(); 1180 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1181 /* 1182 * Thread is in tsleep. 1183 */ 1184 1185 /* 1186 * If the thread is sleeping uninterruptibly 1187 * we can't interrupt the sleep... the signal will 1188 * be noticed when the lwp returns through 1189 * trap() or syscall(). 1190 * 1191 * Otherwise the signal can interrupt the sleep. 1192 * 1193 * If the process is traced, the lwp will handle the 1194 * tracing in issignal() when it returns to userland. 1195 */ 1196 if (lp->lwp_flag & LWP_SINTR) { 1197 /* 1198 * Make runnable and break out of any tsleep as well. 1199 */ 1200 lp->lwp_flag |= LWP_BREAKTSLEEP; 1201 setrunnable(lp); 1202 } 1203 } else { 1204 /* 1205 * Otherwise the thread is running 1206 * 1207 * LSRUN does nothing with the signal, other than kicking 1208 * ourselves if we are running. 1209 * SZOMB and SIDL mean that it will either never be noticed, 1210 * or noticed very soon. 1211 * 1212 * Note that lwp_thread may be NULL or may not be completely 1213 * initialized if the process is in the SIDL or SZOMB state. 1214 * 1215 * For SMP we may have to forward the request to another cpu. 1216 * YYY the MP lock prevents the target process from moving 1217 * to another cpu, see kern/kern_switch.c 1218 * 1219 * If the target thread is waiting on its message port, 1220 * wakeup the target thread so it can check (or ignore) 1221 * the new signal. YYY needs cleanup. 1222 */ 1223 if (lp == lwkt_preempted_proc()) { 1224 signotify(); 1225 } else if (lp->lwp_stat == LSRUN) { 1226 struct thread *td = lp->lwp_thread; 1227 struct proc *p = lp->lwp_proc; 1228 1229 KASSERT(td != NULL, 1230 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1231 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1232 p->p_flag, lp->lwp_flag)); 1233 1234 /* 1235 * To prevent a MP race with TDF_SINTR we must 1236 * schedule the thread on the correct cpu. 1237 */ 1238 #ifdef SMP 1239 if (td->td_gd != mycpu) 1240 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1241 else 1242 #endif 1243 if (td->td_flags & TDF_SINTR) 1244 lwkt_schedule(td); 1245 } 1246 } 1247 crit_exit(); 1248 } 1249 1250 #ifdef SMP 1251 1252 /* 1253 * This function is called via an IPI. We will be in a critical section but 1254 * the MP lock will NOT be held. Also note that by the time the ipi message 1255 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1256 */ 1257 static void 1258 signotify_remote(void *arg) 1259 { 1260 struct lwp *lp = arg; 1261 1262 if (lp == lwkt_preempted_proc()) { 1263 signotify(); 1264 } else { 1265 struct thread *td = lp->lwp_thread; 1266 if (td->td_flags & TDF_SINTR) 1267 lwkt_schedule(td); 1268 } 1269 } 1270 1271 #endif 1272 1273 void 1274 proc_stop(struct proc *p) 1275 { 1276 struct lwp *lp; 1277 1278 /* If somebody raced us, be happy with it */ 1279 if (p->p_stat == SSTOP) 1280 return; 1281 1282 crit_enter(); 1283 p->p_stat = SSTOP; 1284 1285 FOREACH_LWP_IN_PROC(lp, p) { 1286 switch (lp->lwp_stat) { 1287 case LSSTOP: 1288 /* 1289 * Do nothing, we are already counted in 1290 * p_nstopped. 1291 */ 1292 break; 1293 1294 case LSSLEEP: 1295 /* 1296 * We're sleeping, but we will stop before 1297 * returning to userspace, so count us 1298 * as stopped as well. We set LWP_WSTOP 1299 * to signal the lwp that it should not 1300 * increase p_nstopped when reaching tstop(). 1301 */ 1302 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1303 lp->lwp_flag |= LWP_WSTOP; 1304 ++p->p_nstopped; 1305 } 1306 break; 1307 1308 case LSRUN: 1309 /* 1310 * We might notify ourself, but that's not 1311 * a problem. 1312 */ 1313 lwp_signotify(lp); 1314 break; 1315 } 1316 } 1317 1318 if (p->p_nstopped == p->p_nthreads) { 1319 p->p_flag &= ~P_WAITED; 1320 wakeup(p->p_pptr); 1321 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1322 ksignal(p->p_pptr, SIGCHLD); 1323 } 1324 crit_exit(); 1325 } 1326 1327 void 1328 proc_unstop(struct proc *p) 1329 { 1330 struct lwp *lp; 1331 1332 if (p->p_stat != SSTOP) 1333 return; 1334 1335 crit_enter(); 1336 p->p_stat = SACTIVE; 1337 1338 FOREACH_LWP_IN_PROC(lp, p) { 1339 switch (lp->lwp_stat) { 1340 case LSRUN: 1341 /* 1342 * Uh? Not stopped? Well, I guess that's okay. 1343 */ 1344 if (bootverbose) 1345 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1346 p->p_pid, lp->lwp_tid); 1347 break; 1348 1349 case LSSLEEP: 1350 /* 1351 * Still sleeping. Don't bother waking it up. 1352 * However, if this thread was counted as 1353 * stopped, undo this. 1354 * 1355 * Nevertheless we call setrunnable() so that it 1356 * will wake up in case a signal or timeout arrived 1357 * in the meantime. 1358 */ 1359 if (lp->lwp_flag & LWP_WSTOP) { 1360 lp->lwp_flag &= ~LWP_WSTOP; 1361 --p->p_nstopped; 1362 } else { 1363 if (bootverbose) 1364 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1365 p->p_pid, lp->lwp_tid); 1366 } 1367 /* FALLTHROUGH */ 1368 1369 case LSSTOP: 1370 setrunnable(lp); 1371 break; 1372 1373 } 1374 } 1375 crit_exit(); 1376 } 1377 1378 static int 1379 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1380 { 1381 sigset_t savedmask, set; 1382 struct proc *p = curproc; 1383 struct lwp *lp = curthread->td_lwp; 1384 int error, sig, hz, timevalid = 0; 1385 struct timespec rts, ets, ts; 1386 struct timeval tv; 1387 1388 error = 0; 1389 sig = 0; 1390 ets.tv_sec = 0; /* silence compiler warning */ 1391 ets.tv_nsec = 0; /* silence compiler warning */ 1392 SIG_CANTMASK(waitset); 1393 savedmask = lp->lwp_sigmask; 1394 1395 if (timeout) { 1396 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1397 timeout->tv_nsec < 1000000000) { 1398 timevalid = 1; 1399 getnanouptime(&rts); 1400 ets = rts; 1401 timespecadd(&ets, timeout); 1402 } 1403 } 1404 1405 for (;;) { 1406 set = lwp_sigpend(lp); 1407 SIGSETAND(set, waitset); 1408 if ((sig = sig_ffs(&set)) != 0) { 1409 SIGFILLSET(lp->lwp_sigmask); 1410 SIGDELSET(lp->lwp_sigmask, sig); 1411 SIG_CANTMASK(lp->lwp_sigmask); 1412 sig = issignal(lp); 1413 /* 1414 * It may be a STOP signal, in the case, issignal 1415 * returns 0, because we may stop there, and new 1416 * signal can come in, we should restart if we got 1417 * nothing. 1418 */ 1419 if (sig == 0) 1420 continue; 1421 else 1422 break; 1423 } 1424 1425 /* 1426 * Previous checking got nothing, and we retried but still 1427 * got nothing, we should return the error status. 1428 */ 1429 if (error) 1430 break; 1431 1432 /* 1433 * POSIX says this must be checked after looking for pending 1434 * signals. 1435 */ 1436 if (timeout) { 1437 if (timevalid == 0) { 1438 error = EINVAL; 1439 break; 1440 } 1441 getnanouptime(&rts); 1442 if (timespeccmp(&rts, &ets, >=)) { 1443 error = EAGAIN; 1444 break; 1445 } 1446 ts = ets; 1447 timespecsub(&ts, &rts); 1448 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1449 hz = tvtohz_high(&tv); 1450 } else 1451 hz = 0; 1452 1453 lp->lwp_sigmask = savedmask; 1454 SIGSETNAND(lp->lwp_sigmask, waitset); 1455 /* 1456 * We won't ever be woken up. Instead, our sleep will 1457 * be broken in lwpsignal(). 1458 */ 1459 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1460 if (timeout) { 1461 if (error == ERESTART) { 1462 /* can not restart a timeout wait. */ 1463 error = EINTR; 1464 } else if (error == EAGAIN) { 1465 /* will calculate timeout by ourself. */ 1466 error = 0; 1467 } 1468 } 1469 /* Retry ... */ 1470 } 1471 1472 lp->lwp_sigmask = savedmask; 1473 if (sig) { 1474 error = 0; 1475 bzero(info, sizeof(*info)); 1476 info->si_signo = sig; 1477 lwp_delsig(lp, sig); /* take the signal! */ 1478 1479 if (sig == SIGKILL) 1480 sigexit(lp, sig); 1481 } 1482 return (error); 1483 } 1484 1485 int 1486 sys_sigtimedwait(struct sigtimedwait_args *uap) 1487 { 1488 struct timespec ts; 1489 struct timespec *timeout; 1490 sigset_t set; 1491 siginfo_t info; 1492 int error; 1493 1494 if (uap->timeout) { 1495 error = copyin(uap->timeout, &ts, sizeof(ts)); 1496 if (error) 1497 return (error); 1498 timeout = &ts; 1499 } else { 1500 timeout = NULL; 1501 } 1502 error = copyin(uap->set, &set, sizeof(set)); 1503 if (error) 1504 return (error); 1505 error = kern_sigtimedwait(set, &info, timeout); 1506 if (error) 1507 return (error); 1508 if (uap->info) 1509 error = copyout(&info, uap->info, sizeof(info)); 1510 /* Repost if we got an error. */ 1511 /* 1512 * XXX lwp 1513 * 1514 * This could transform a thread-specific signal to another 1515 * thread / process pending signal. 1516 */ 1517 if (error) 1518 ksignal(curproc, info.si_signo); 1519 else 1520 uap->sysmsg_result = info.si_signo; 1521 return (error); 1522 } 1523 1524 int 1525 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1526 { 1527 siginfo_t info; 1528 sigset_t set; 1529 int error; 1530 1531 error = copyin(uap->set, &set, sizeof(set)); 1532 if (error) 1533 return (error); 1534 error = kern_sigtimedwait(set, &info, NULL); 1535 if (error) 1536 return (error); 1537 if (uap->info) 1538 error = copyout(&info, uap->info, sizeof(info)); 1539 /* Repost if we got an error. */ 1540 /* 1541 * XXX lwp 1542 * 1543 * This could transform a thread-specific signal to another 1544 * thread / process pending signal. 1545 */ 1546 if (error) 1547 ksignal(curproc, info.si_signo); 1548 else 1549 uap->sysmsg_result = info.si_signo; 1550 return (error); 1551 } 1552 1553 /* 1554 * If the current process has received a signal that would interrupt a 1555 * system call, return EINTR or ERESTART as appropriate. 1556 */ 1557 int 1558 iscaught(struct lwp *lp) 1559 { 1560 struct proc *p = lp->lwp_proc; 1561 int sig; 1562 1563 if (p) { 1564 if ((sig = CURSIG(lp)) != 0) { 1565 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1566 return (EINTR); 1567 return (ERESTART); 1568 } 1569 } 1570 return(EWOULDBLOCK); 1571 } 1572 1573 /* 1574 * If the current process has received a signal (should be caught or cause 1575 * termination, should interrupt current syscall), return the signal number. 1576 * Stop signals with default action are processed immediately, then cleared; 1577 * they aren't returned. This is checked after each entry to the system for 1578 * a syscall or trap (though this can usually be done without calling issignal 1579 * by checking the pending signal masks in the CURSIG macro.) The normal call 1580 * sequence is 1581 * 1582 * This routine is called via CURSIG/__cursig and the MP lock might not be 1583 * held. Obtain the MP lock for the duration of the operation. 1584 * 1585 * while (sig = CURSIG(curproc)) 1586 * postsig(sig); 1587 */ 1588 int 1589 issignal(struct lwp *lp) 1590 { 1591 struct proc *p = lp->lwp_proc; 1592 sigset_t mask; 1593 int sig, prop; 1594 1595 get_mplock(); 1596 for (;;) { 1597 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1598 1599 mask = lwp_sigpend(lp); 1600 SIGSETNAND(mask, lp->lwp_sigmask); 1601 if (p->p_flag & P_PPWAIT) 1602 SIG_STOPSIGMASK(mask); 1603 if (SIGISEMPTY(mask)) { /* no signal to send */ 1604 rel_mplock(); 1605 return (0); 1606 } 1607 sig = sig_ffs(&mask); 1608 1609 STOPEVENT(p, S_SIG, sig); 1610 1611 /* 1612 * We should see pending but ignored signals 1613 * only if P_TRACED was on when they were posted. 1614 */ 1615 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1616 lwp_delsig(lp, sig); 1617 continue; 1618 } 1619 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1620 /* 1621 * If traced, always stop, and stay stopped until 1622 * released by the parent. 1623 * 1624 * NOTE: SSTOP may get cleared during the loop, 1625 * but we do not re-notify the parent if we have 1626 * to loop several times waiting for the parent 1627 * to let us continue. 1628 * 1629 * XXX not sure if this is still true 1630 */ 1631 p->p_xstat = sig; 1632 proc_stop(p); 1633 do { 1634 tstop(); 1635 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1636 1637 /* 1638 * If parent wants us to take the signal, 1639 * then it will leave it in p->p_xstat; 1640 * otherwise we just look for signals again. 1641 */ 1642 lwp_delsig(lp, sig); /* clear old signal */ 1643 sig = p->p_xstat; 1644 if (sig == 0) 1645 continue; 1646 1647 /* 1648 * Put the new signal into p_siglist. If the 1649 * signal is being masked, look for other signals. 1650 * 1651 * XXX lwp might need a call to ksignal() 1652 */ 1653 SIGADDSET(p->p_siglist, sig); 1654 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1655 continue; 1656 1657 /* 1658 * If the traced bit got turned off, go back up 1659 * to the top to rescan signals. This ensures 1660 * that p_sig* and ps_sigact are consistent. 1661 */ 1662 if ((p->p_flag & P_TRACED) == 0) 1663 continue; 1664 } 1665 1666 prop = sigprop(sig); 1667 1668 /* 1669 * Decide whether the signal should be returned. 1670 * Return the signal's number, or fall through 1671 * to clear it from the pending mask. 1672 */ 1673 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1674 case (int)SIG_DFL: 1675 /* 1676 * Don't take default actions on system processes. 1677 */ 1678 if (p->p_pid <= 1) { 1679 #ifdef DIAGNOSTIC 1680 /* 1681 * Are you sure you want to ignore SIGSEGV 1682 * in init? XXX 1683 */ 1684 kprintf("Process (pid %lu) got signal %d\n", 1685 (u_long)p->p_pid, sig); 1686 #endif 1687 break; /* == ignore */ 1688 } 1689 1690 /* 1691 * Handle the in-kernel checkpoint action 1692 */ 1693 if (prop & SA_CKPT) { 1694 checkpoint_signal_handler(lp); 1695 break; 1696 } 1697 1698 /* 1699 * If there is a pending stop signal to process 1700 * with default action, stop here, 1701 * then clear the signal. However, 1702 * if process is member of an orphaned 1703 * process group, ignore tty stop signals. 1704 */ 1705 if (prop & SA_STOP) { 1706 if (p->p_flag & P_TRACED || 1707 (p->p_pgrp->pg_jobc == 0 && 1708 prop & SA_TTYSTOP)) 1709 break; /* == ignore */ 1710 p->p_xstat = sig; 1711 proc_stop(p); 1712 while (p->p_stat == SSTOP) { 1713 tstop(); 1714 } 1715 break; 1716 } else if (prop & SA_IGNORE) { 1717 /* 1718 * Except for SIGCONT, shouldn't get here. 1719 * Default action is to ignore; drop it. 1720 */ 1721 break; /* == ignore */ 1722 } else { 1723 rel_mplock(); 1724 return (sig); 1725 } 1726 1727 /*NOTREACHED*/ 1728 1729 case (int)SIG_IGN: 1730 /* 1731 * Masking above should prevent us ever trying 1732 * to take action on an ignored signal other 1733 * than SIGCONT, unless process is traced. 1734 */ 1735 if ((prop & SA_CONT) == 0 && 1736 (p->p_flag & P_TRACED) == 0) 1737 kprintf("issignal\n"); 1738 break; /* == ignore */ 1739 1740 default: 1741 /* 1742 * This signal has an action, let 1743 * postsig() process it. 1744 */ 1745 rel_mplock(); 1746 return (sig); 1747 } 1748 lwp_delsig(lp, sig); /* take the signal! */ 1749 } 1750 /* NOTREACHED */ 1751 } 1752 1753 /* 1754 * Take the action for the specified signal 1755 * from the current set of pending signals. 1756 */ 1757 void 1758 postsig(int sig) 1759 { 1760 struct lwp *lp = curthread->td_lwp; 1761 struct proc *p = lp->lwp_proc; 1762 struct sigacts *ps = p->p_sigacts; 1763 sig_t action; 1764 sigset_t returnmask; 1765 int code; 1766 1767 KASSERT(sig != 0, ("postsig")); 1768 1769 /* 1770 * If we are a virtual kernel running an emulated user process 1771 * context, switch back to the virtual kernel context before 1772 * trying to post the signal. 1773 */ 1774 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1775 struct trapframe *tf = lp->lwp_md.md_regs; 1776 tf->tf_trapno = 0; 1777 vkernel_trap(lp, tf); 1778 } 1779 1780 lwp_delsig(lp, sig); 1781 action = ps->ps_sigact[_SIG_IDX(sig)]; 1782 #ifdef KTRACE 1783 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1784 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1785 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1786 #endif 1787 STOPEVENT(p, S_SIG, sig); 1788 1789 if (action == SIG_DFL) { 1790 /* 1791 * Default action, where the default is to kill 1792 * the process. (Other cases were ignored above.) 1793 */ 1794 sigexit(lp, sig); 1795 /* NOTREACHED */ 1796 } else { 1797 /* 1798 * If we get here, the signal must be caught. 1799 */ 1800 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1801 ("postsig action")); 1802 1803 crit_enter(); 1804 1805 /* 1806 * Reset the signal handler if asked to 1807 */ 1808 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1809 /* 1810 * See kern_sigaction() for origin of this code. 1811 */ 1812 SIGDELSET(p->p_sigcatch, sig); 1813 if (sig != SIGCONT && 1814 sigprop(sig) & SA_IGNORE) 1815 SIGADDSET(p->p_sigignore, sig); 1816 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1817 } 1818 1819 /* 1820 * Handle the mailbox case. Copyout to the appropriate 1821 * location but do not generate a signal frame. The system 1822 * call simply returns EINTR and the user is responsible for 1823 * polling the mailbox. 1824 */ 1825 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1826 int sig_copy = sig; 1827 copyout(&sig_copy, (void *)action, sizeof(int)); 1828 curproc->p_flag |= P_MAILBOX; 1829 crit_exit(); 1830 goto done; 1831 } 1832 1833 /* 1834 * Set the signal mask and calculate the mask to restore 1835 * when the signal function returns. 1836 * 1837 * Special case: user has done a sigsuspend. Here the 1838 * current mask is not of interest, but rather the 1839 * mask from before the sigsuspend is what we want 1840 * restored after the signal processing is completed. 1841 */ 1842 if (lp->lwp_flag & LWP_OLDMASK) { 1843 returnmask = lp->lwp_oldsigmask; 1844 lp->lwp_flag &= ~LWP_OLDMASK; 1845 } else { 1846 returnmask = lp->lwp_sigmask; 1847 } 1848 1849 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1850 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1851 SIGADDSET(lp->lwp_sigmask, sig); 1852 1853 crit_exit(); 1854 lp->lwp_ru.ru_nsignals++; 1855 if (lp->lwp_sig != sig) { 1856 code = 0; 1857 } else { 1858 code = lp->lwp_code; 1859 lp->lwp_code = 0; 1860 lp->lwp_sig = 0; 1861 } 1862 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1863 } 1864 done: 1865 ; 1866 } 1867 1868 /* 1869 * Kill the current process for stated reason. 1870 */ 1871 void 1872 killproc(struct proc *p, char *why) 1873 { 1874 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1875 p->p_pid, p->p_comm, 1876 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1877 ksignal(p, SIGKILL); 1878 } 1879 1880 /* 1881 * Force the current process to exit with the specified signal, dumping core 1882 * if appropriate. We bypass the normal tests for masked and caught signals, 1883 * allowing unrecoverable failures to terminate the process without changing 1884 * signal state. Mark the accounting record with the signal termination. 1885 * If dumping core, save the signal number for the debugger. Calls exit and 1886 * does not return. 1887 */ 1888 void 1889 sigexit(struct lwp *lp, int sig) 1890 { 1891 struct proc *p = lp->lwp_proc; 1892 1893 p->p_acflag |= AXSIG; 1894 if (sigprop(sig) & SA_CORE) { 1895 lp->lwp_sig = sig; 1896 /* 1897 * Log signals which would cause core dumps 1898 * (Log as LOG_INFO to appease those who don't want 1899 * these messages.) 1900 * XXX : Todo, as well as euid, write out ruid too 1901 */ 1902 if (coredump(lp, sig) == 0) 1903 sig |= WCOREFLAG; 1904 if (kern_logsigexit) 1905 log(LOG_INFO, 1906 "pid %d (%s), uid %d: exited on signal %d%s\n", 1907 p->p_pid, p->p_comm, 1908 p->p_ucred ? p->p_ucred->cr_uid : -1, 1909 sig &~ WCOREFLAG, 1910 sig & WCOREFLAG ? " (core dumped)" : ""); 1911 } 1912 exit1(W_EXITCODE(0, sig)); 1913 /* NOTREACHED */ 1914 } 1915 1916 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1917 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1918 sizeof(corefilename), "process corefile name format string"); 1919 1920 /* 1921 * expand_name(name, uid, pid) 1922 * Expand the name described in corefilename, using name, uid, and pid. 1923 * corefilename is a kprintf-like string, with three format specifiers: 1924 * %N name of process ("name") 1925 * %P process id (pid) 1926 * %U user id (uid) 1927 * For example, "%N.core" is the default; they can be disabled completely 1928 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1929 * This is controlled by the sysctl variable kern.corefile (see above). 1930 */ 1931 1932 static char * 1933 expand_name(const char *name, uid_t uid, pid_t pid) 1934 { 1935 char *temp; 1936 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1937 int i, n; 1938 char *format = corefilename; 1939 size_t namelen; 1940 1941 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1942 if (temp == NULL) 1943 return NULL; 1944 namelen = strlen(name); 1945 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1946 int l; 1947 switch (format[i]) { 1948 case '%': /* Format character */ 1949 i++; 1950 switch (format[i]) { 1951 case '%': 1952 temp[n++] = '%'; 1953 break; 1954 case 'N': /* process name */ 1955 if ((n + namelen) > MAXPATHLEN) { 1956 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1957 pid, name, uid, temp, name); 1958 kfree(temp, M_TEMP); 1959 return NULL; 1960 } 1961 memcpy(temp+n, name, namelen); 1962 n += namelen; 1963 break; 1964 case 'P': /* process id */ 1965 l = ksprintf(buf, "%u", pid); 1966 if ((n + l) > MAXPATHLEN) { 1967 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1968 pid, name, uid, temp, name); 1969 kfree(temp, M_TEMP); 1970 return NULL; 1971 } 1972 memcpy(temp+n, buf, l); 1973 n += l; 1974 break; 1975 case 'U': /* user id */ 1976 l = ksprintf(buf, "%u", uid); 1977 if ((n + l) > MAXPATHLEN) { 1978 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1979 pid, name, uid, temp, name); 1980 kfree(temp, M_TEMP); 1981 return NULL; 1982 } 1983 memcpy(temp+n, buf, l); 1984 n += l; 1985 break; 1986 default: 1987 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1988 } 1989 break; 1990 default: 1991 temp[n++] = format[i]; 1992 } 1993 } 1994 temp[n] = '\0'; 1995 return temp; 1996 } 1997 1998 /* 1999 * Dump a process' core. The main routine does some 2000 * policy checking, and creates the name of the coredump; 2001 * then it passes on a vnode and a size limit to the process-specific 2002 * coredump routine if there is one; if there _is not_ one, it returns 2003 * ENOSYS; otherwise it returns the error from the process-specific routine. 2004 * 2005 * The parameter `lp' is the lwp which triggered the coredump. 2006 */ 2007 2008 static int 2009 coredump(struct lwp *lp, int sig) 2010 { 2011 struct proc *p = lp->lwp_proc; 2012 struct vnode *vp; 2013 struct ucred *cred = p->p_ucred; 2014 struct flock lf; 2015 struct nlookupdata nd; 2016 struct vattr vattr; 2017 int error, error1; 2018 char *name; /* name of corefile */ 2019 off_t limit; 2020 2021 STOPEVENT(p, S_CORE, 0); 2022 2023 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2024 return (EFAULT); 2025 2026 /* 2027 * Note that the bulk of limit checking is done after 2028 * the corefile is created. The exception is if the limit 2029 * for corefiles is 0, in which case we don't bother 2030 * creating the corefile at all. This layout means that 2031 * a corefile is truncated instead of not being created, 2032 * if it is larger than the limit. 2033 */ 2034 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2035 if (limit == 0) 2036 return EFBIG; 2037 2038 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2039 if (name == NULL) 2040 return (EINVAL); 2041 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2042 if (error == 0) 2043 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2044 kfree(name, M_TEMP); 2045 if (error) { 2046 nlookup_done(&nd); 2047 return (error); 2048 } 2049 vp = nd.nl_open_vp; 2050 nd.nl_open_vp = NULL; 2051 nlookup_done(&nd); 2052 2053 vn_unlock(vp); 2054 lf.l_whence = SEEK_SET; 2055 lf.l_start = 0; 2056 lf.l_len = 0; 2057 lf.l_type = F_WRLCK; 2058 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2059 if (error) 2060 goto out2; 2061 2062 /* Don't dump to non-regular files or files with links. */ 2063 if (vp->v_type != VREG || 2064 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2065 error = EFAULT; 2066 goto out1; 2067 } 2068 2069 /* Don't dump to files current user does not own */ 2070 if (vattr.va_uid != p->p_ucred->cr_uid) { 2071 error = EFAULT; 2072 goto out1; 2073 } 2074 2075 VATTR_NULL(&vattr); 2076 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2077 vattr.va_size = 0; 2078 VOP_SETATTR(vp, &vattr, cred); 2079 p->p_acflag |= ACORE; 2080 vn_unlock(vp); 2081 2082 error = p->p_sysent->sv_coredump ? 2083 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2084 2085 out1: 2086 lf.l_type = F_UNLCK; 2087 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2088 out2: 2089 error1 = vn_close(vp, FWRITE); 2090 if (error == 0) 2091 error = error1; 2092 return (error); 2093 } 2094 2095 /* 2096 * Nonexistent system call-- signal process (may want to handle it). 2097 * Flag error in case process won't see signal immediately (blocked or ignored). 2098 */ 2099 /* ARGSUSED */ 2100 int 2101 sys_nosys(struct nosys_args *args) 2102 { 2103 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2104 return (EINVAL); 2105 } 2106 2107 /* 2108 * Send a SIGIO or SIGURG signal to a process or process group using 2109 * stored credentials rather than those of the current process. 2110 */ 2111 void 2112 pgsigio(struct sigio *sigio, int sig, int checkctty) 2113 { 2114 if (sigio == NULL) 2115 return; 2116 2117 if (sigio->sio_pgid > 0) { 2118 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2119 sigio->sio_proc)) 2120 ksignal(sigio->sio_proc, sig); 2121 } else if (sigio->sio_pgid < 0) { 2122 struct proc *p; 2123 2124 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2125 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2126 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2127 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2128 ksignal(p, sig); 2129 } 2130 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2131 } 2132 } 2133 2134 static int 2135 filt_sigattach(struct knote *kn) 2136 { 2137 struct proc *p = curproc; 2138 2139 kn->kn_ptr.p_proc = p; 2140 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2141 2142 /* XXX lock the proc here while adding to the list? */ 2143 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 2144 2145 return (0); 2146 } 2147 2148 static void 2149 filt_sigdetach(struct knote *kn) 2150 { 2151 struct proc *p = kn->kn_ptr.p_proc; 2152 2153 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 2154 } 2155 2156 /* 2157 * signal knotes are shared with proc knotes, so we apply a mask to 2158 * the hint in order to differentiate them from process hints. This 2159 * could be avoided by using a signal-specific knote list, but probably 2160 * isn't worth the trouble. 2161 */ 2162 static int 2163 filt_signal(struct knote *kn, long hint) 2164 { 2165 if (hint & NOTE_SIGNAL) { 2166 hint &= ~NOTE_SIGNAL; 2167 2168 if (kn->kn_id == hint) 2169 kn->kn_data++; 2170 } 2171 return (kn->kn_data != 0); 2172 } 2173