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 1.90 2008/06/09 04:33:08 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/resourcevar.h> 51 #include <sys/vnode.h> 52 #include <sys/event.h> 53 #include <sys/proc.h> 54 #include <sys/nlookup.h> 55 #include <sys/pioctl.h> 56 #include <sys/systm.h> 57 #include <sys/acct.h> 58 #include <sys/fcntl.h> 59 #include <sys/lock.h> 60 #include <sys/wait.h> 61 #include <sys/ktrace.h> 62 #include <sys/syslog.h> 63 #include <sys/stat.h> 64 #include <sys/sysent.h> 65 #include <sys/sysctl.h> 66 #include <sys/malloc.h> 67 #include <sys/interrupt.h> 68 #include <sys/unistd.h> 69 #include <sys/kern_syscall.h> 70 #include <sys/vkernel.h> 71 72 #include <sys/signal2.h> 73 #include <sys/thread2.h> 74 #include <sys/mplock2.h> 75 76 #include <machine/cpu.h> 77 #include <machine/smp.h> 78 79 static int coredump(struct lwp *, int); 80 static char *expand_name(const char *, uid_t, pid_t); 81 static int dokillpg(int sig, int pgid, int all); 82 static int sig_ffs(sigset_t *set); 83 static int sigprop(int sig); 84 #ifdef SMP 85 static void signotify_remote(void *arg); 86 #endif 87 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 88 struct timespec *timeout); 89 90 static int filt_sigattach(struct knote *kn); 91 static void filt_sigdetach(struct knote *kn); 92 static int filt_signal(struct knote *kn, long hint); 93 94 struct filterops sig_filtops = 95 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 96 97 static int kern_logsigexit = 1; 98 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 99 &kern_logsigexit, 0, 100 "Log processes quitting on abnormal signals to syslog(3)"); 101 102 /* 103 * Can process p, with pcred pc, send the signal sig to process q? 104 */ 105 #define CANSIGNAL(q, sig) \ 106 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 107 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 108 109 /* 110 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 111 */ 112 #define CANSIGIO(ruid, uc, q) \ 113 ((uc)->cr_uid == 0 || \ 114 (ruid) == (q)->p_ucred->cr_ruid || \ 115 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 116 (ruid) == (q)->p_ucred->cr_uid || \ 117 (uc)->cr_uid == (q)->p_ucred->cr_uid) 118 119 int sugid_coredump; 120 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 121 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 122 123 static int do_coredump = 1; 124 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 125 &do_coredump, 0, "Enable/Disable coredumps"); 126 127 /* 128 * Signal properties and actions. 129 * The array below categorizes the signals and their default actions 130 * according to the following properties: 131 */ 132 #define SA_KILL 0x01 /* terminates process by default */ 133 #define SA_CORE 0x02 /* ditto and coredumps */ 134 #define SA_STOP 0x04 /* suspend process */ 135 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 136 #define SA_IGNORE 0x10 /* ignore by default */ 137 #define SA_CONT 0x20 /* continue if suspended */ 138 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 139 #define SA_CKPT 0x80 /* checkpoint process */ 140 141 142 static int sigproptbl[NSIG] = { 143 SA_KILL, /* SIGHUP */ 144 SA_KILL, /* SIGINT */ 145 SA_KILL|SA_CORE, /* SIGQUIT */ 146 SA_KILL|SA_CORE, /* SIGILL */ 147 SA_KILL|SA_CORE, /* SIGTRAP */ 148 SA_KILL|SA_CORE, /* SIGABRT */ 149 SA_KILL|SA_CORE, /* SIGEMT */ 150 SA_KILL|SA_CORE, /* SIGFPE */ 151 SA_KILL, /* SIGKILL */ 152 SA_KILL|SA_CORE, /* SIGBUS */ 153 SA_KILL|SA_CORE, /* SIGSEGV */ 154 SA_KILL|SA_CORE, /* SIGSYS */ 155 SA_KILL, /* SIGPIPE */ 156 SA_KILL, /* SIGALRM */ 157 SA_KILL, /* SIGTERM */ 158 SA_IGNORE, /* SIGURG */ 159 SA_STOP, /* SIGSTOP */ 160 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 161 SA_IGNORE|SA_CONT, /* SIGCONT */ 162 SA_IGNORE, /* SIGCHLD */ 163 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 164 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 165 SA_IGNORE, /* SIGIO */ 166 SA_KILL, /* SIGXCPU */ 167 SA_KILL, /* SIGXFSZ */ 168 SA_KILL, /* SIGVTALRM */ 169 SA_KILL, /* SIGPROF */ 170 SA_IGNORE, /* SIGWINCH */ 171 SA_IGNORE, /* SIGINFO */ 172 SA_KILL, /* SIGUSR1 */ 173 SA_KILL, /* SIGUSR2 */ 174 SA_IGNORE, /* SIGTHR */ 175 SA_CKPT, /* SIGCKPT */ 176 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 206 SA_IGNORE, 207 208 }; 209 210 static __inline int 211 sigprop(int sig) 212 { 213 214 if (sig > 0 && sig < NSIG) 215 return (sigproptbl[_SIG_IDX(sig)]); 216 return (0); 217 } 218 219 static __inline int 220 sig_ffs(sigset_t *set) 221 { 222 int i; 223 224 for (i = 0; i < _SIG_WORDS; i++) 225 if (set->__bits[i]) 226 return (ffs(set->__bits[i]) + (i * 32)); 227 return (0); 228 } 229 230 int 231 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 232 { 233 struct thread *td = curthread; 234 struct proc *p = td->td_proc; 235 struct lwp *lp; 236 struct sigacts *ps = p->p_sigacts; 237 238 if (sig <= 0 || sig > _SIG_MAXSIG) 239 return (EINVAL); 240 241 if (oact) { 242 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 243 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 244 oact->sa_flags = 0; 245 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 246 oact->sa_flags |= SA_ONSTACK; 247 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 248 oact->sa_flags |= SA_RESTART; 249 if (SIGISMEMBER(ps->ps_sigreset, sig)) 250 oact->sa_flags |= SA_RESETHAND; 251 if (SIGISMEMBER(ps->ps_signodefer, sig)) 252 oact->sa_flags |= SA_NODEFER; 253 if (SIGISMEMBER(ps->ps_siginfo, sig)) 254 oact->sa_flags |= SA_SIGINFO; 255 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 256 oact->sa_flags |= SA_MAILBOX; 257 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 258 oact->sa_flags |= SA_NOCLDSTOP; 259 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 260 oact->sa_flags |= SA_NOCLDWAIT; 261 } 262 if (act) { 263 /* 264 * Check for invalid requests. KILL and STOP cannot be 265 * caught. 266 */ 267 if (sig == SIGKILL || sig == SIGSTOP) { 268 if (act->sa_handler != SIG_DFL) 269 return (EINVAL); 270 #if 0 271 /* (not needed, SIG_DFL forces action to occur) */ 272 if (act->sa_flags & SA_MAILBOX) 273 return (EINVAL); 274 #endif 275 } 276 277 /* 278 * Change setting atomically. 279 */ 280 crit_enter(); 281 282 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 283 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 284 if (act->sa_flags & SA_SIGINFO) { 285 ps->ps_sigact[_SIG_IDX(sig)] = 286 (__sighandler_t *)act->sa_sigaction; 287 SIGADDSET(ps->ps_siginfo, sig); 288 } else { 289 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 290 SIGDELSET(ps->ps_siginfo, sig); 291 } 292 if (!(act->sa_flags & SA_RESTART)) 293 SIGADDSET(ps->ps_sigintr, sig); 294 else 295 SIGDELSET(ps->ps_sigintr, sig); 296 if (act->sa_flags & SA_ONSTACK) 297 SIGADDSET(ps->ps_sigonstack, sig); 298 else 299 SIGDELSET(ps->ps_sigonstack, sig); 300 if (act->sa_flags & SA_RESETHAND) 301 SIGADDSET(ps->ps_sigreset, sig); 302 else 303 SIGDELSET(ps->ps_sigreset, sig); 304 if (act->sa_flags & SA_NODEFER) 305 SIGADDSET(ps->ps_signodefer, sig); 306 else 307 SIGDELSET(ps->ps_signodefer, sig); 308 if (act->sa_flags & SA_MAILBOX) 309 SIGADDSET(ps->ps_sigmailbox, sig); 310 else 311 SIGDELSET(ps->ps_sigmailbox, sig); 312 if (sig == SIGCHLD) { 313 if (act->sa_flags & SA_NOCLDSTOP) 314 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 315 else 316 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 317 if (act->sa_flags & SA_NOCLDWAIT) { 318 /* 319 * Paranoia: since SA_NOCLDWAIT is implemented 320 * by reparenting the dying child to PID 1 (and 321 * trust it to reap the zombie), PID 1 itself 322 * is forbidden to set SA_NOCLDWAIT. 323 */ 324 if (p->p_pid == 1) 325 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 326 else 327 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 328 } else { 329 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 330 } 331 } 332 /* 333 * Set bit in p_sigignore for signals that are set to SIG_IGN, 334 * and for signals set to SIG_DFL where the default is to 335 * ignore. However, don't put SIGCONT in p_sigignore, as we 336 * have to restart the process. 337 */ 338 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 339 (sigprop(sig) & SA_IGNORE && 340 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 341 /* never to be seen again */ 342 SIGDELSET(p->p_siglist, sig); 343 /* 344 * Remove the signal also from the thread lists. 345 */ 346 FOREACH_LWP_IN_PROC(lp, p) { 347 SIGDELSET(lp->lwp_siglist, sig); 348 } 349 if (sig != SIGCONT) 350 /* easier in ksignal */ 351 SIGADDSET(p->p_sigignore, sig); 352 SIGDELSET(p->p_sigcatch, sig); 353 } else { 354 SIGDELSET(p->p_sigignore, sig); 355 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 356 SIGDELSET(p->p_sigcatch, sig); 357 else 358 SIGADDSET(p->p_sigcatch, sig); 359 } 360 361 crit_exit(); 362 } 363 return (0); 364 } 365 366 /* 367 * MPALMOSTSAFE 368 */ 369 int 370 sys_sigaction(struct sigaction_args *uap) 371 { 372 struct sigaction act, oact; 373 struct sigaction *actp, *oactp; 374 int error; 375 376 actp = (uap->act != NULL) ? &act : NULL; 377 oactp = (uap->oact != NULL) ? &oact : NULL; 378 if (actp) { 379 error = copyin(uap->act, actp, sizeof(act)); 380 if (error) 381 return (error); 382 } 383 get_mplock(); 384 error = kern_sigaction(uap->sig, actp, oactp); 385 rel_mplock(); 386 if (oactp && !error) { 387 error = copyout(oactp, uap->oact, sizeof(oact)); 388 } 389 return (error); 390 } 391 392 /* 393 * Initialize signal state for process 0; 394 * set to ignore signals that are ignored by default. 395 */ 396 void 397 siginit(struct proc *p) 398 { 399 int i; 400 401 for (i = 1; i <= NSIG; i++) 402 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 403 SIGADDSET(p->p_sigignore, i); 404 } 405 406 /* 407 * Reset signals for an exec of the specified process. 408 */ 409 void 410 execsigs(struct proc *p) 411 { 412 struct sigacts *ps = p->p_sigacts; 413 struct lwp *lp; 414 int sig; 415 416 lp = ONLY_LWP_IN_PROC(p); 417 418 /* 419 * Reset caught signals. Held signals remain held 420 * through p_sigmask (unless they were caught, 421 * and are now ignored by default). 422 */ 423 while (SIGNOTEMPTY(p->p_sigcatch)) { 424 sig = sig_ffs(&p->p_sigcatch); 425 SIGDELSET(p->p_sigcatch, sig); 426 if (sigprop(sig) & SA_IGNORE) { 427 if (sig != SIGCONT) 428 SIGADDSET(p->p_sigignore, sig); 429 SIGDELSET(p->p_siglist, sig); 430 SIGDELSET(lp->lwp_siglist, sig); 431 } 432 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 433 } 434 435 /* 436 * Reset stack state to the user stack. 437 * Clear set of signals caught on the signal stack. 438 */ 439 lp->lwp_sigstk.ss_flags = SS_DISABLE; 440 lp->lwp_sigstk.ss_size = 0; 441 lp->lwp_sigstk.ss_sp = 0; 442 lp->lwp_flag &= ~LWP_ALTSTACK; 443 /* 444 * Reset no zombies if child dies flag as Solaris does. 445 */ 446 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 447 } 448 449 /* 450 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 451 * 452 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 453 * p == curproc. 454 */ 455 int 456 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 457 { 458 struct thread *td = curthread; 459 struct lwp *lp = td->td_lwp; 460 int error; 461 462 if (oset != NULL) 463 *oset = lp->lwp_sigmask; 464 465 error = 0; 466 if (set != NULL) { 467 switch (how) { 468 case SIG_BLOCK: 469 SIG_CANTMASK(*set); 470 SIGSETOR(lp->lwp_sigmask, *set); 471 break; 472 case SIG_UNBLOCK: 473 SIGSETNAND(lp->lwp_sigmask, *set); 474 break; 475 case SIG_SETMASK: 476 SIG_CANTMASK(*set); 477 lp->lwp_sigmask = *set; 478 break; 479 default: 480 error = EINVAL; 481 break; 482 } 483 } 484 return (error); 485 } 486 487 /* 488 * sigprocmask() 489 * 490 * MPSAFE 491 */ 492 int 493 sys_sigprocmask(struct sigprocmask_args *uap) 494 { 495 sigset_t set, oset; 496 sigset_t *setp, *osetp; 497 int error; 498 499 setp = (uap->set != NULL) ? &set : NULL; 500 osetp = (uap->oset != NULL) ? &oset : NULL; 501 if (setp) { 502 error = copyin(uap->set, setp, sizeof(set)); 503 if (error) 504 return (error); 505 } 506 error = kern_sigprocmask(uap->how, setp, osetp); 507 if (osetp && !error) { 508 error = copyout(osetp, uap->oset, sizeof(oset)); 509 } 510 return (error); 511 } 512 513 /* 514 * MPSAFE 515 */ 516 int 517 kern_sigpending(struct __sigset *set) 518 { 519 struct lwp *lp = curthread->td_lwp; 520 521 *set = lwp_sigpend(lp); 522 523 return (0); 524 } 525 526 /* 527 * MPSAFE 528 */ 529 int 530 sys_sigpending(struct sigpending_args *uap) 531 { 532 sigset_t set; 533 int error; 534 535 error = kern_sigpending(&set); 536 537 if (error == 0) 538 error = copyout(&set, uap->set, sizeof(set)); 539 return (error); 540 } 541 542 /* 543 * Suspend process until signal, providing mask to be set 544 * in the meantime. 545 * 546 * MPSAFE 547 */ 548 int 549 kern_sigsuspend(struct __sigset *set) 550 { 551 struct thread *td = curthread; 552 struct lwp *lp = td->td_lwp; 553 struct proc *p = td->td_proc; 554 struct sigacts *ps = p->p_sigacts; 555 556 /* 557 * When returning from sigsuspend, we want 558 * the old mask to be restored after the 559 * signal handler has finished. Thus, we 560 * save it here and mark the sigacts structure 561 * to indicate this. 562 */ 563 lp->lwp_oldsigmask = lp->lwp_sigmask; 564 lp->lwp_flag |= LWP_OLDMASK; 565 566 SIG_CANTMASK(*set); 567 lp->lwp_sigmask = *set; 568 while (tsleep(ps, PCATCH, "pause", 0) == 0) 569 /* void */; 570 /* always return EINTR rather than ERESTART... */ 571 return (EINTR); 572 } 573 574 /* 575 * Note nonstandard calling convention: libc stub passes mask, not 576 * pointer, to save a copyin. 577 * 578 * MPSAFE 579 */ 580 int 581 sys_sigsuspend(struct sigsuspend_args *uap) 582 { 583 sigset_t mask; 584 int error; 585 586 error = copyin(uap->sigmask, &mask, sizeof(mask)); 587 if (error) 588 return (error); 589 590 error = kern_sigsuspend(&mask); 591 592 return (error); 593 } 594 595 /* 596 * MPSAFE 597 */ 598 int 599 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 600 { 601 struct thread *td = curthread; 602 struct lwp *lp = td->td_lwp; 603 struct proc *p = td->td_proc; 604 605 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 606 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 607 608 if (oss) 609 *oss = lp->lwp_sigstk; 610 611 if (ss) { 612 if (ss->ss_flags & SS_DISABLE) { 613 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 614 return (EINVAL); 615 lp->lwp_flag &= ~LWP_ALTSTACK; 616 lp->lwp_sigstk.ss_flags = ss->ss_flags; 617 } else { 618 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 619 return (ENOMEM); 620 lp->lwp_flag |= LWP_ALTSTACK; 621 lp->lwp_sigstk = *ss; 622 } 623 } 624 625 return (0); 626 } 627 628 /* 629 * MPSAFE 630 */ 631 int 632 sys_sigaltstack(struct sigaltstack_args *uap) 633 { 634 stack_t ss, oss; 635 int error; 636 637 if (uap->ss) { 638 error = copyin(uap->ss, &ss, sizeof(ss)); 639 if (error) 640 return (error); 641 } 642 643 error = kern_sigaltstack(uap->ss ? &ss : NULL, 644 uap->oss ? &oss : NULL); 645 646 if (error == 0 && uap->oss) 647 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 648 return (error); 649 } 650 651 /* 652 * Common code for kill process group/broadcast kill. 653 * cp is calling process. 654 */ 655 struct killpg_info { 656 int nfound; 657 int sig; 658 }; 659 660 static int killpg_all_callback(struct proc *p, void *data); 661 662 static int 663 dokillpg(int sig, int pgid, int all) 664 { 665 struct killpg_info info; 666 struct proc *cp = curproc; 667 struct proc *p; 668 struct pgrp *pgrp; 669 670 info.nfound = 0; 671 info.sig = sig; 672 673 if (all) { 674 /* 675 * broadcast 676 */ 677 allproc_scan(killpg_all_callback, &info); 678 } else { 679 if (pgid == 0) { 680 /* 681 * zero pgid means send to my process group. 682 */ 683 pgrp = cp->p_pgrp; 684 } else { 685 pgrp = pgfind(pgid); 686 if (pgrp == NULL) 687 return (ESRCH); 688 } 689 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 690 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 691 if (p->p_pid <= 1 || 692 p->p_stat == SZOMB || 693 (p->p_flag & P_SYSTEM) || 694 !CANSIGNAL(p, sig)) { 695 continue; 696 } 697 ++info.nfound; 698 if (sig) 699 ksignal(p, sig); 700 } 701 lockmgr(&pgrp->pg_lock, LK_RELEASE); 702 } 703 return (info.nfound ? 0 : ESRCH); 704 } 705 706 static int 707 killpg_all_callback(struct proc *p, void *data) 708 { 709 struct killpg_info *info = data; 710 711 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 712 p == curproc || !CANSIGNAL(p, info->sig)) { 713 return (0); 714 } 715 ++info->nfound; 716 if (info->sig) 717 ksignal(p, info->sig); 718 return(0); 719 } 720 721 /* 722 * Send a general signal to a process or LWPs within that process. Note 723 * that new signals cannot be sent if a process is exiting. 724 */ 725 int 726 kern_kill(int sig, pid_t pid, lwpid_t tid) 727 { 728 if ((u_int)sig > _SIG_MAXSIG) 729 return (EINVAL); 730 if (pid > 0) { 731 struct proc *p; 732 struct lwp *lp = NULL; 733 734 /* kill single process */ 735 if ((p = pfind(pid)) == NULL) 736 return (ESRCH); 737 if (!CANSIGNAL(p, sig)) 738 return (EPERM); 739 740 /* 741 * NOP if the process is exiting. Note that lwpsignal() is 742 * called directly with P_WEXIT set to kill individual LWPs 743 * during exit, which is allowed. 744 */ 745 if (p->p_flag & P_WEXIT) 746 return (0); 747 if (tid != -1) { 748 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 749 if (lp == NULL) 750 return (ESRCH); 751 } 752 if (sig) 753 lwpsignal(p, lp, sig); 754 return (0); 755 } 756 /* 757 * If we come here, pid is a special broadcast pid. 758 * This doesn't mix with a tid. 759 */ 760 if (tid != -1) 761 return (EINVAL); 762 switch (pid) { 763 case -1: /* broadcast signal */ 764 return (dokillpg(sig, 0, 1)); 765 case 0: /* signal own process group */ 766 return (dokillpg(sig, 0, 0)); 767 default: /* negative explicit process group */ 768 return (dokillpg(sig, -pid, 0)); 769 } 770 /* NOTREACHED */ 771 } 772 773 /* 774 * MPALMOSTSAFE 775 */ 776 int 777 sys_kill(struct kill_args *uap) 778 { 779 int error; 780 781 get_mplock(); 782 error = kern_kill(uap->signum, uap->pid, -1); 783 rel_mplock(); 784 return (error); 785 } 786 787 /* 788 * MPALMOSTSAFE 789 */ 790 int 791 sys_lwp_kill(struct lwp_kill_args *uap) 792 { 793 int error; 794 pid_t pid = uap->pid; 795 796 /* 797 * A tid is mandatory for lwp_kill(), otherwise 798 * you could simply use kill(). 799 */ 800 if (uap->tid == -1) 801 return (EINVAL); 802 803 /* 804 * To save on a getpid() function call for intra-process 805 * signals, pid == -1 means current process. 806 */ 807 if (pid == -1) 808 pid = curproc->p_pid; 809 810 get_mplock(); 811 error = kern_kill(uap->signum, pid, uap->tid); 812 rel_mplock(); 813 return (error); 814 } 815 816 /* 817 * Send a signal to a process group. 818 */ 819 void 820 gsignal(int pgid, int sig) 821 { 822 struct pgrp *pgrp; 823 824 if (pgid && (pgrp = pgfind(pgid))) 825 pgsignal(pgrp, sig, 0); 826 } 827 828 /* 829 * Send a signal to a process group. If checktty is 1, 830 * limit to members which have a controlling terminal. 831 * 832 * pg_lock interlocks against a fork that might be in progress, to 833 * ensure that the new child process picks up the signal. 834 */ 835 void 836 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 837 { 838 struct proc *p; 839 840 if (pgrp) { 841 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 842 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 843 if (checkctty == 0 || p->p_flag & P_CONTROLT) 844 ksignal(p, sig); 845 } 846 lockmgr(&pgrp->pg_lock, LK_RELEASE); 847 } 848 } 849 850 /* 851 * Send a signal caused by a trap to the current lwp. If it will be caught 852 * immediately, deliver it with correct code. Otherwise, post it normally. 853 * 854 * These signals may ONLY be delivered to the specified lwp and may never 855 * be delivered to the process generically. 856 */ 857 void 858 trapsignal(struct lwp *lp, int sig, u_long code) 859 { 860 struct proc *p = lp->lwp_proc; 861 struct sigacts *ps = p->p_sigacts; 862 863 /* 864 * If we are a virtual kernel running an emulated user process 865 * context, switch back to the virtual kernel context before 866 * trying to post the signal. 867 */ 868 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 869 struct trapframe *tf = lp->lwp_md.md_regs; 870 tf->tf_trapno = 0; 871 vkernel_trap(lp, tf); 872 } 873 874 875 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 876 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 877 lp->lwp_ru.ru_nsignals++; 878 #ifdef KTRACE 879 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 880 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 881 &lp->lwp_sigmask, code); 882 #endif 883 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 884 &lp->lwp_sigmask, code); 885 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 886 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 887 SIGADDSET(lp->lwp_sigmask, sig); 888 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 889 /* 890 * See kern_sigaction() for origin of this code. 891 */ 892 SIGDELSET(p->p_sigcatch, sig); 893 if (sig != SIGCONT && 894 sigprop(sig) & SA_IGNORE) 895 SIGADDSET(p->p_sigignore, sig); 896 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 897 } 898 } else { 899 lp->lwp_code = code; /* XXX for core dump/debugger */ 900 lp->lwp_sig = sig; /* XXX to verify code */ 901 lwpsignal(p, lp, sig); 902 } 903 } 904 905 /* 906 * Find a suitable lwp to deliver the signal to. 907 * 908 * Returns NULL if all lwps hold the signal blocked. 909 */ 910 static struct lwp * 911 find_lwp_for_signal(struct proc *p, int sig) 912 { 913 struct lwp *lp; 914 struct lwp *run, *sleep, *stop; 915 916 /* 917 * If the running/preempted thread belongs to the proc to which 918 * the signal is being delivered and this thread does not block 919 * the signal, then we can avoid a context switch by delivering 920 * the signal to this thread, because it will return to userland 921 * soon anyways. 922 */ 923 lp = lwkt_preempted_proc(); 924 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig)) 925 return (lp); 926 927 run = sleep = stop = NULL; 928 FOREACH_LWP_IN_PROC(lp, p) { 929 /* 930 * If the signal is being blocked by the lwp, then this 931 * lwp is not eligible for receiving the signal. 932 */ 933 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 934 continue; 935 936 switch (lp->lwp_stat) { 937 case LSRUN: 938 run = lp; 939 break; 940 941 case LSSTOP: 942 stop = lp; 943 break; 944 945 case LSSLEEP: 946 if (lp->lwp_flag & LWP_SINTR) 947 sleep = lp; 948 break; 949 } 950 } 951 952 if (run != NULL) 953 return (run); 954 else if (sleep != NULL) 955 return (sleep); 956 else 957 return (stop); 958 } 959 960 /* 961 * Send the signal to the process. If the signal has an action, the action 962 * is usually performed by the target process rather than the caller; we add 963 * the signal to the set of pending signals for the process. 964 * 965 * Exceptions: 966 * o When a stop signal is sent to a sleeping process that takes the 967 * default action, the process is stopped without awakening it. 968 * o SIGCONT restarts stopped processes (or puts them back to sleep) 969 * regardless of the signal action (eg, blocked or ignored). 970 * 971 * Other ignored signals are discarded immediately. 972 */ 973 void 974 ksignal(struct proc *p, int sig) 975 { 976 lwpsignal(p, NULL, sig); 977 } 978 979 /* 980 * The core for ksignal. lp may be NULL, then a suitable thread 981 * will be chosen. If not, lp MUST be a member of p. 982 */ 983 void 984 lwpsignal(struct proc *p, struct lwp *lp, int sig) 985 { 986 int prop; 987 sig_t action; 988 989 if (sig > _SIG_MAXSIG || sig <= 0) { 990 kprintf("lwpsignal: signal %d\n", sig); 991 panic("lwpsignal signal number"); 992 } 993 994 KKASSERT(lp == NULL || lp->lwp_proc == p); 995 996 prop = sigprop(sig); 997 998 /* 999 * If proc is traced, always give parent a chance; 1000 * if signal event is tracked by procfs, give *that* 1001 * a chance, as well. 1002 */ 1003 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1004 action = SIG_DFL; 1005 } else { 1006 /* 1007 * Do not try to deliver signals to an exiting lwp. Note 1008 * that we must still deliver the signal if P_WEXIT is set 1009 * in the process flags. 1010 */ 1011 if (lp && (lp->lwp_flag & LWP_WEXIT)) 1012 return; 1013 1014 /* 1015 * If the signal is being ignored, then we forget about 1016 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1017 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1018 */ 1019 if (SIGISMEMBER(p->p_sigignore, sig)) 1020 return; 1021 if (SIGISMEMBER(p->p_sigcatch, sig)) 1022 action = SIG_CATCH; 1023 else 1024 action = SIG_DFL; 1025 } 1026 1027 /* 1028 * If continuing, clear any pending STOP signals. 1029 */ 1030 if (prop & SA_CONT) 1031 SIG_STOPSIGMASK(p->p_siglist); 1032 1033 if (prop & SA_STOP) { 1034 /* 1035 * If sending a tty stop signal to a member of an orphaned 1036 * process group, discard the signal here if the action 1037 * is default; don't stop the process below if sleeping, 1038 * and don't clear any pending SIGCONT. 1039 */ 1040 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1041 action == SIG_DFL) { 1042 return; 1043 } 1044 SIG_CONTSIGMASK(p->p_siglist); 1045 p->p_flag &= ~P_CONTINUED; 1046 } 1047 1048 crit_enter(); 1049 1050 if (p->p_stat == SSTOP) { 1051 /* 1052 * Nobody can handle this signal, add it to the lwp or 1053 * process pending list 1054 */ 1055 if (lp) 1056 SIGADDSET(lp->lwp_siglist, sig); 1057 else 1058 SIGADDSET(p->p_siglist, sig); 1059 1060 /* 1061 * If the process is stopped and is being traced, then no 1062 * further action is necessary. 1063 */ 1064 if (p->p_flag & P_TRACED) 1065 goto out; 1066 1067 /* 1068 * If the process is stopped and receives a KILL signal, 1069 * make the process runnable. 1070 */ 1071 if (sig == SIGKILL) { 1072 proc_unstop(p); 1073 goto active_process; 1074 } 1075 1076 /* 1077 * If the process is stopped and receives a CONT signal, 1078 * then try to make the process runnable again. 1079 */ 1080 if (prop & SA_CONT) { 1081 /* 1082 * If SIGCONT is default (or ignored), we continue the 1083 * process but don't leave the signal in p_siglist, as 1084 * it has no further action. If SIGCONT is held, we 1085 * continue the process and leave the signal in 1086 * p_siglist. If the process catches SIGCONT, let it 1087 * handle the signal itself. 1088 */ 1089 /* XXX what if the signal is being held blocked? */ 1090 p->p_flag |= P_CONTINUED; 1091 wakeup(p->p_pptr); 1092 if (action == SIG_DFL) 1093 SIGDELSET(p->p_siglist, sig); 1094 proc_unstop(p); 1095 if (action == SIG_CATCH) 1096 goto active_process; 1097 goto out; 1098 } 1099 1100 /* 1101 * If the process is stopped and receives another STOP 1102 * signal, we do not need to stop it again. If we did 1103 * the shell could get confused. 1104 * 1105 * However, if the current/preempted lwp is part of the 1106 * process receiving the signal, we need to keep it, 1107 * so that this lwp can stop in issignal() later, as 1108 * we don't want to wait until it reaches userret! 1109 */ 1110 if (prop & SA_STOP) { 1111 if (lwkt_preempted_proc() == NULL || 1112 lwkt_preempted_proc()->lwp_proc != p) 1113 SIGDELSET(p->p_siglist, sig); 1114 } 1115 1116 /* 1117 * Otherwise the process is stopped and it received some 1118 * signal, which does not change its stopped state. 1119 * 1120 * We have to select one thread to set LWP_BREAKTSLEEP, 1121 * so that the current signal will break the sleep 1122 * as soon as a SA_CONT signal will unstop the process. 1123 */ 1124 if (lp == NULL) 1125 lp = find_lwp_for_signal(p, sig); 1126 if (lp != NULL && 1127 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1128 lp->lwp_flag |= LWP_BREAKTSLEEP; 1129 goto out; 1130 1131 /* NOTREACHED */ 1132 } 1133 /* else not stopped */ 1134 active_process: 1135 1136 /* 1137 * Never deliver a lwp-specific signal to a random lwp. 1138 */ 1139 if (lp == NULL) { 1140 lp = find_lwp_for_signal(p, sig); 1141 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1142 lp = NULL; 1143 } 1144 1145 /* 1146 * Deliver to the process generically if (1) the signal is being 1147 * sent to any thread or (2) we could not find a thread to deliver 1148 * it to. 1149 */ 1150 if (lp == NULL) { 1151 SIGADDSET(p->p_siglist, sig); 1152 goto out; 1153 } 1154 1155 /* 1156 * Deliver to a specific LWP whether it masks it or not. It will 1157 * not be dispatched if masked but we must still deliver it. 1158 */ 1159 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1160 (p->p_flag & P_TRACED) == 0) { 1161 p->p_nice = NZERO; 1162 } 1163 1164 /* 1165 * If the process receives a STOP signal which indeed needs to 1166 * stop the process, do so. If the process chose to catch the 1167 * signal, it will be treated like any other signal. 1168 */ 1169 if ((prop & SA_STOP) && action == SIG_DFL) { 1170 /* 1171 * If a child holding parent blocked, stopping 1172 * could cause deadlock. Take no action at this 1173 * time. 1174 */ 1175 if (p->p_flag & P_PPWAIT) { 1176 SIGADDSET(p->p_siglist, sig); 1177 goto out; 1178 } 1179 1180 /* 1181 * Do not actually try to manipulate the process, but simply 1182 * stop it. Lwps will stop as soon as they safely can. 1183 */ 1184 p->p_xstat = sig; 1185 proc_stop(p); 1186 goto out; 1187 } 1188 1189 /* 1190 * If it is a CONT signal with default action, just ignore it. 1191 */ 1192 if ((prop & SA_CONT) && action == SIG_DFL) 1193 goto out; 1194 1195 /* 1196 * Mark signal pending at this specific thread. 1197 */ 1198 SIGADDSET(lp->lwp_siglist, sig); 1199 1200 lwp_signotify(lp); 1201 1202 out: 1203 crit_exit(); 1204 } 1205 1206 void 1207 lwp_signotify(struct lwp *lp) 1208 { 1209 crit_enter(); 1210 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1211 /* 1212 * Thread is in tsleep. 1213 */ 1214 1215 /* 1216 * If the thread is sleeping uninterruptibly 1217 * we can't interrupt the sleep... the signal will 1218 * be noticed when the lwp returns through 1219 * trap() or syscall(). 1220 * 1221 * Otherwise the signal can interrupt the sleep. 1222 * 1223 * If the process is traced, the lwp will handle the 1224 * tracing in issignal() when it returns to userland. 1225 */ 1226 if (lp->lwp_flag & LWP_SINTR) { 1227 /* 1228 * Make runnable and break out of any tsleep as well. 1229 */ 1230 lp->lwp_flag |= LWP_BREAKTSLEEP; 1231 setrunnable(lp); 1232 } 1233 } else { 1234 /* 1235 * Otherwise the thread is running 1236 * 1237 * LSRUN does nothing with the signal, other than kicking 1238 * ourselves if we are running. 1239 * SZOMB and SIDL mean that it will either never be noticed, 1240 * or noticed very soon. 1241 * 1242 * Note that lwp_thread may be NULL or may not be completely 1243 * initialized if the process is in the SIDL or SZOMB state. 1244 * 1245 * For SMP we may have to forward the request to another cpu. 1246 * YYY the MP lock prevents the target process from moving 1247 * to another cpu, see kern/kern_switch.c 1248 * 1249 * If the target thread is waiting on its message port, 1250 * wakeup the target thread so it can check (or ignore) 1251 * the new signal. YYY needs cleanup. 1252 */ 1253 if (lp == lwkt_preempted_proc()) { 1254 signotify(); 1255 } else if (lp->lwp_stat == LSRUN) { 1256 struct thread *td = lp->lwp_thread; 1257 struct proc *p __debugvar = lp->lwp_proc; 1258 1259 KASSERT(td != NULL, 1260 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1261 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1262 p->p_flag, lp->lwp_flag)); 1263 1264 /* 1265 * To prevent a MP race with TDF_SINTR we must 1266 * schedule the thread on the correct cpu. 1267 */ 1268 #ifdef SMP 1269 if (td->td_gd != mycpu) { 1270 LWPHOLD(lp); 1271 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1272 } else 1273 #endif 1274 if (td->td_flags & TDF_SINTR) 1275 lwkt_schedule(td); 1276 } 1277 } 1278 crit_exit(); 1279 } 1280 1281 #ifdef SMP 1282 1283 /* 1284 * This function is called via an IPI. We will be in a critical section but 1285 * the MP lock will NOT be held. Also note that by the time the ipi message 1286 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1287 */ 1288 static void 1289 signotify_remote(void *arg) 1290 { 1291 struct lwp *lp = arg; 1292 1293 if (lp == lwkt_preempted_proc()) { 1294 signotify(); 1295 } else { 1296 struct thread *td = lp->lwp_thread; 1297 if (td->td_flags & TDF_SINTR) 1298 lwkt_schedule(td); 1299 } 1300 LWPRELE(lp); 1301 } 1302 1303 #endif 1304 1305 void 1306 proc_stop(struct proc *p) 1307 { 1308 struct lwp *lp; 1309 1310 /* If somebody raced us, be happy with it */ 1311 if (p->p_stat == SSTOP || p->p_stat == SZOMB) 1312 return; 1313 1314 crit_enter(); 1315 p->p_stat = SSTOP; 1316 1317 FOREACH_LWP_IN_PROC(lp, p) { 1318 switch (lp->lwp_stat) { 1319 case LSSTOP: 1320 /* 1321 * Do nothing, we are already counted in 1322 * p_nstopped. 1323 */ 1324 break; 1325 1326 case LSSLEEP: 1327 /* 1328 * We're sleeping, but we will stop before 1329 * returning to userspace, so count us 1330 * as stopped as well. We set LWP_WSTOP 1331 * to signal the lwp that it should not 1332 * increase p_nstopped when reaching tstop(). 1333 */ 1334 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1335 lp->lwp_flag |= LWP_WSTOP; 1336 ++p->p_nstopped; 1337 } 1338 break; 1339 1340 case LSRUN: 1341 /* 1342 * We might notify ourself, but that's not 1343 * a problem. 1344 */ 1345 lwp_signotify(lp); 1346 break; 1347 } 1348 } 1349 1350 if (p->p_nstopped == p->p_nthreads) { 1351 p->p_flag &= ~P_WAITED; 1352 wakeup(p->p_pptr); 1353 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1354 ksignal(p->p_pptr, SIGCHLD); 1355 } 1356 crit_exit(); 1357 } 1358 1359 void 1360 proc_unstop(struct proc *p) 1361 { 1362 struct lwp *lp; 1363 1364 if (p->p_stat != SSTOP) 1365 return; 1366 1367 crit_enter(); 1368 p->p_stat = SACTIVE; 1369 1370 FOREACH_LWP_IN_PROC(lp, p) { 1371 switch (lp->lwp_stat) { 1372 case LSRUN: 1373 /* 1374 * Uh? Not stopped? Well, I guess that's okay. 1375 */ 1376 if (bootverbose) 1377 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1378 p->p_pid, lp->lwp_tid); 1379 break; 1380 1381 case LSSLEEP: 1382 /* 1383 * Still sleeping. Don't bother waking it up. 1384 * However, if this thread was counted as 1385 * stopped, undo this. 1386 * 1387 * Nevertheless we call setrunnable() so that it 1388 * will wake up in case a signal or timeout arrived 1389 * in the meantime. 1390 */ 1391 if (lp->lwp_flag & LWP_WSTOP) { 1392 lp->lwp_flag &= ~LWP_WSTOP; 1393 --p->p_nstopped; 1394 } else { 1395 if (bootverbose) 1396 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1397 p->p_pid, lp->lwp_tid); 1398 } 1399 /* FALLTHROUGH */ 1400 1401 case LSSTOP: 1402 setrunnable(lp); 1403 break; 1404 1405 } 1406 } 1407 crit_exit(); 1408 } 1409 1410 static int 1411 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1412 { 1413 sigset_t savedmask, set; 1414 struct proc *p = curproc; 1415 struct lwp *lp = curthread->td_lwp; 1416 int error, sig, hz, timevalid = 0; 1417 struct timespec rts, ets, ts; 1418 struct timeval tv; 1419 1420 error = 0; 1421 sig = 0; 1422 ets.tv_sec = 0; /* silence compiler warning */ 1423 ets.tv_nsec = 0; /* silence compiler warning */ 1424 SIG_CANTMASK(waitset); 1425 savedmask = lp->lwp_sigmask; 1426 1427 if (timeout) { 1428 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1429 timeout->tv_nsec < 1000000000) { 1430 timevalid = 1; 1431 getnanouptime(&rts); 1432 ets = rts; 1433 timespecadd(&ets, timeout); 1434 } 1435 } 1436 1437 for (;;) { 1438 set = lwp_sigpend(lp); 1439 SIGSETAND(set, waitset); 1440 if ((sig = sig_ffs(&set)) != 0) { 1441 SIGFILLSET(lp->lwp_sigmask); 1442 SIGDELSET(lp->lwp_sigmask, sig); 1443 SIG_CANTMASK(lp->lwp_sigmask); 1444 sig = issignal(lp, 1); 1445 /* 1446 * It may be a STOP signal, in the case, issignal 1447 * returns 0, because we may stop there, and new 1448 * signal can come in, we should restart if we got 1449 * nothing. 1450 */ 1451 if (sig == 0) 1452 continue; 1453 else 1454 break; 1455 } 1456 1457 /* 1458 * Previous checking got nothing, and we retried but still 1459 * got nothing, we should return the error status. 1460 */ 1461 if (error) 1462 break; 1463 1464 /* 1465 * POSIX says this must be checked after looking for pending 1466 * signals. 1467 */ 1468 if (timeout) { 1469 if (timevalid == 0) { 1470 error = EINVAL; 1471 break; 1472 } 1473 getnanouptime(&rts); 1474 if (timespeccmp(&rts, &ets, >=)) { 1475 error = EAGAIN; 1476 break; 1477 } 1478 ts = ets; 1479 timespecsub(&ts, &rts); 1480 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1481 hz = tvtohz_high(&tv); 1482 } else 1483 hz = 0; 1484 1485 lp->lwp_sigmask = savedmask; 1486 SIGSETNAND(lp->lwp_sigmask, waitset); 1487 /* 1488 * We won't ever be woken up. Instead, our sleep will 1489 * be broken in lwpsignal(). 1490 */ 1491 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1492 if (timeout) { 1493 if (error == ERESTART) { 1494 /* can not restart a timeout wait. */ 1495 error = EINTR; 1496 } else if (error == EAGAIN) { 1497 /* will calculate timeout by ourself. */ 1498 error = 0; 1499 } 1500 } 1501 /* Retry ... */ 1502 } 1503 1504 lp->lwp_sigmask = savedmask; 1505 if (sig) { 1506 error = 0; 1507 bzero(info, sizeof(*info)); 1508 info->si_signo = sig; 1509 lwp_delsig(lp, sig); /* take the signal! */ 1510 1511 if (sig == SIGKILL) 1512 sigexit(lp, sig); 1513 } 1514 return (error); 1515 } 1516 1517 /* 1518 * MPALMOSTSAFE 1519 */ 1520 int 1521 sys_sigtimedwait(struct sigtimedwait_args *uap) 1522 { 1523 struct timespec ts; 1524 struct timespec *timeout; 1525 sigset_t set; 1526 siginfo_t info; 1527 int error; 1528 1529 if (uap->timeout) { 1530 error = copyin(uap->timeout, &ts, sizeof(ts)); 1531 if (error) 1532 return (error); 1533 timeout = &ts; 1534 } else { 1535 timeout = NULL; 1536 } 1537 error = copyin(uap->set, &set, sizeof(set)); 1538 if (error) 1539 return (error); 1540 get_mplock(); 1541 error = kern_sigtimedwait(set, &info, timeout); 1542 rel_mplock(); 1543 if (error) 1544 return (error); 1545 if (uap->info) 1546 error = copyout(&info, uap->info, sizeof(info)); 1547 /* Repost if we got an error. */ 1548 /* 1549 * XXX lwp 1550 * 1551 * This could transform a thread-specific signal to another 1552 * thread / process pending signal. 1553 */ 1554 if (error) { 1555 get_mplock(); 1556 ksignal(curproc, info.si_signo); 1557 rel_mplock(); 1558 } else { 1559 uap->sysmsg_result = info.si_signo; 1560 } 1561 return (error); 1562 } 1563 1564 /* 1565 * MPALMOSTSAFE 1566 */ 1567 int 1568 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1569 { 1570 siginfo_t info; 1571 sigset_t set; 1572 int error; 1573 1574 error = copyin(uap->set, &set, sizeof(set)); 1575 if (error) 1576 return (error); 1577 get_mplock(); 1578 error = kern_sigtimedwait(set, &info, NULL); 1579 rel_mplock(); 1580 if (error) 1581 return (error); 1582 if (uap->info) 1583 error = copyout(&info, uap->info, sizeof(info)); 1584 /* Repost if we got an error. */ 1585 /* 1586 * XXX lwp 1587 * 1588 * This could transform a thread-specific signal to another 1589 * thread / process pending signal. 1590 */ 1591 if (error) { 1592 get_mplock(); 1593 ksignal(curproc, info.si_signo); 1594 rel_mplock(); 1595 } else { 1596 uap->sysmsg_result = info.si_signo; 1597 } 1598 return (error); 1599 } 1600 1601 /* 1602 * If the current process has received a signal that would interrupt a 1603 * system call, return EINTR or ERESTART as appropriate. 1604 */ 1605 int 1606 iscaught(struct lwp *lp) 1607 { 1608 struct proc *p = lp->lwp_proc; 1609 int sig; 1610 1611 if (p) { 1612 if ((sig = CURSIG(lp)) != 0) { 1613 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1614 return (EINTR); 1615 return (ERESTART); 1616 } 1617 } 1618 return(EWOULDBLOCK); 1619 } 1620 1621 /* 1622 * If the current process has received a signal (should be caught or cause 1623 * termination, should interrupt current syscall), return the signal number. 1624 * Stop signals with default action are processed immediately, then cleared; 1625 * they aren't returned. This is checked after each entry to the system for 1626 * a syscall or trap (though this can usually be done without calling issignal 1627 * by checking the pending signal masks in the CURSIG macro.) The normal call 1628 * sequence is 1629 * 1630 * This routine is called via CURSIG/__cursig and the MP lock might not be 1631 * held. Obtain the MP lock for the duration of the operation. 1632 * 1633 * while (sig = CURSIG(curproc)) 1634 * postsig(sig); 1635 */ 1636 int 1637 issignal(struct lwp *lp, int maytrace) 1638 { 1639 struct proc *p = lp->lwp_proc; 1640 sigset_t mask; 1641 int sig, prop; 1642 1643 get_mplock(); 1644 for (;;) { 1645 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1646 1647 /* 1648 * If this process is supposed to stop, stop this thread. 1649 */ 1650 if (p->p_stat == SSTOP) 1651 tstop(); 1652 1653 mask = lwp_sigpend(lp); 1654 SIGSETNAND(mask, lp->lwp_sigmask); 1655 if (p->p_flag & P_PPWAIT) 1656 SIG_STOPSIGMASK(mask); 1657 if (SIGISEMPTY(mask)) { /* no signal to send */ 1658 rel_mplock(); 1659 return (0); 1660 } 1661 sig = sig_ffs(&mask); 1662 1663 STOPEVENT(p, S_SIG, sig); 1664 1665 /* 1666 * We should see pending but ignored signals 1667 * only if P_TRACED was on when they were posted. 1668 */ 1669 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1670 lwp_delsig(lp, sig); 1671 continue; 1672 } 1673 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1674 /* 1675 * If traced, always stop, and stay stopped until 1676 * released by the parent. 1677 * 1678 * NOTE: SSTOP may get cleared during the loop, 1679 * but we do not re-notify the parent if we have 1680 * to loop several times waiting for the parent 1681 * to let us continue. 1682 * 1683 * XXX not sure if this is still true 1684 */ 1685 p->p_xstat = sig; 1686 proc_stop(p); 1687 do { 1688 tstop(); 1689 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1690 1691 /* 1692 * If parent wants us to take the signal, 1693 * then it will leave it in p->p_xstat; 1694 * otherwise we just look for signals again. 1695 */ 1696 lwp_delsig(lp, sig); /* clear old signal */ 1697 sig = p->p_xstat; 1698 if (sig == 0) 1699 continue; 1700 1701 /* 1702 * Put the new signal into p_siglist. If the 1703 * signal is being masked, look for other signals. 1704 * 1705 * XXX lwp might need a call to ksignal() 1706 */ 1707 SIGADDSET(p->p_siglist, sig); 1708 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1709 continue; 1710 1711 /* 1712 * If the traced bit got turned off, go back up 1713 * to the top to rescan signals. This ensures 1714 * that p_sig* and ps_sigact are consistent. 1715 */ 1716 if ((p->p_flag & P_TRACED) == 0) 1717 continue; 1718 } 1719 1720 prop = sigprop(sig); 1721 1722 /* 1723 * Decide whether the signal should be returned. 1724 * Return the signal's number, or fall through 1725 * to clear it from the pending mask. 1726 */ 1727 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1728 case (intptr_t)SIG_DFL: 1729 /* 1730 * Don't take default actions on system processes. 1731 */ 1732 if (p->p_pid <= 1) { 1733 #ifdef DIAGNOSTIC 1734 /* 1735 * Are you sure you want to ignore SIGSEGV 1736 * in init? XXX 1737 */ 1738 kprintf("Process (pid %lu) got signal %d\n", 1739 (u_long)p->p_pid, sig); 1740 #endif 1741 break; /* == ignore */ 1742 } 1743 1744 /* 1745 * Handle the in-kernel checkpoint action 1746 */ 1747 if (prop & SA_CKPT) { 1748 checkpoint_signal_handler(lp); 1749 break; 1750 } 1751 1752 /* 1753 * If there is a pending stop signal to process 1754 * with default action, stop here, 1755 * then clear the signal. However, 1756 * if process is member of an orphaned 1757 * process group, ignore tty stop signals. 1758 */ 1759 if (prop & SA_STOP) { 1760 if (p->p_flag & P_TRACED || 1761 (p->p_pgrp->pg_jobc == 0 && 1762 prop & SA_TTYSTOP)) 1763 break; /* == ignore */ 1764 p->p_xstat = sig; 1765 proc_stop(p); 1766 tstop(); 1767 break; 1768 } else if (prop & SA_IGNORE) { 1769 /* 1770 * Except for SIGCONT, shouldn't get here. 1771 * Default action is to ignore; drop it. 1772 */ 1773 break; /* == ignore */ 1774 } else { 1775 rel_mplock(); 1776 return (sig); 1777 } 1778 1779 /*NOTREACHED*/ 1780 1781 case (intptr_t)SIG_IGN: 1782 /* 1783 * Masking above should prevent us ever trying 1784 * to take action on an ignored signal other 1785 * than SIGCONT, unless process is traced. 1786 */ 1787 if ((prop & SA_CONT) == 0 && 1788 (p->p_flag & P_TRACED) == 0) 1789 kprintf("issignal\n"); 1790 break; /* == ignore */ 1791 1792 default: 1793 /* 1794 * This signal has an action, let 1795 * postsig() process it. 1796 */ 1797 rel_mplock(); 1798 return (sig); 1799 } 1800 lwp_delsig(lp, sig); /* take the signal! */ 1801 } 1802 /* NOTREACHED */ 1803 } 1804 1805 /* 1806 * Take the action for the specified signal 1807 * from the current set of pending signals. 1808 */ 1809 void 1810 postsig(int sig) 1811 { 1812 struct lwp *lp = curthread->td_lwp; 1813 struct proc *p = lp->lwp_proc; 1814 struct sigacts *ps = p->p_sigacts; 1815 sig_t action; 1816 sigset_t returnmask; 1817 int code; 1818 1819 KASSERT(sig != 0, ("postsig")); 1820 1821 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1822 1823 /* 1824 * If we are a virtual kernel running an emulated user process 1825 * context, switch back to the virtual kernel context before 1826 * trying to post the signal. 1827 */ 1828 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1829 struct trapframe *tf = lp->lwp_md.md_regs; 1830 tf->tf_trapno = 0; 1831 vkernel_trap(lp, tf); 1832 } 1833 1834 lwp_delsig(lp, sig); 1835 action = ps->ps_sigact[_SIG_IDX(sig)]; 1836 #ifdef KTRACE 1837 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1838 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1839 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1840 #endif 1841 STOPEVENT(p, S_SIG, sig); 1842 1843 if (action == SIG_DFL) { 1844 /* 1845 * Default action, where the default is to kill 1846 * the process. (Other cases were ignored above.) 1847 */ 1848 sigexit(lp, sig); 1849 /* NOTREACHED */ 1850 } else { 1851 /* 1852 * If we get here, the signal must be caught. 1853 */ 1854 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1855 ("postsig action")); 1856 1857 crit_enter(); 1858 1859 /* 1860 * Reset the signal handler if asked to 1861 */ 1862 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1863 /* 1864 * See kern_sigaction() for origin of this code. 1865 */ 1866 SIGDELSET(p->p_sigcatch, sig); 1867 if (sig != SIGCONT && 1868 sigprop(sig) & SA_IGNORE) 1869 SIGADDSET(p->p_sigignore, sig); 1870 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1871 } 1872 1873 /* 1874 * Handle the mailbox case. Copyout to the appropriate 1875 * location but do not generate a signal frame. The system 1876 * call simply returns EINTR and the user is responsible for 1877 * polling the mailbox. 1878 */ 1879 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1880 int sig_copy = sig; 1881 copyout(&sig_copy, (void *)action, sizeof(int)); 1882 curproc->p_flag |= P_MAILBOX; 1883 crit_exit(); 1884 goto done; 1885 } 1886 1887 /* 1888 * Set the signal mask and calculate the mask to restore 1889 * when the signal function returns. 1890 * 1891 * Special case: user has done a sigsuspend. Here the 1892 * current mask is not of interest, but rather the 1893 * mask from before the sigsuspend is what we want 1894 * restored after the signal processing is completed. 1895 */ 1896 if (lp->lwp_flag & LWP_OLDMASK) { 1897 returnmask = lp->lwp_oldsigmask; 1898 lp->lwp_flag &= ~LWP_OLDMASK; 1899 } else { 1900 returnmask = lp->lwp_sigmask; 1901 } 1902 1903 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1904 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1905 SIGADDSET(lp->lwp_sigmask, sig); 1906 1907 crit_exit(); 1908 lp->lwp_ru.ru_nsignals++; 1909 if (lp->lwp_sig != sig) { 1910 code = 0; 1911 } else { 1912 code = lp->lwp_code; 1913 lp->lwp_code = 0; 1914 lp->lwp_sig = 0; 1915 } 1916 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1917 } 1918 done: 1919 ; 1920 } 1921 1922 /* 1923 * Kill the current process for stated reason. 1924 */ 1925 void 1926 killproc(struct proc *p, char *why) 1927 { 1928 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1929 p->p_pid, p->p_comm, 1930 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1931 ksignal(p, SIGKILL); 1932 } 1933 1934 /* 1935 * Force the current process to exit with the specified signal, dumping core 1936 * if appropriate. We bypass the normal tests for masked and caught signals, 1937 * allowing unrecoverable failures to terminate the process without changing 1938 * signal state. Mark the accounting record with the signal termination. 1939 * If dumping core, save the signal number for the debugger. Calls exit and 1940 * does not return. 1941 */ 1942 void 1943 sigexit(struct lwp *lp, int sig) 1944 { 1945 struct proc *p = lp->lwp_proc; 1946 1947 p->p_acflag |= AXSIG; 1948 if (sigprop(sig) & SA_CORE) { 1949 lp->lwp_sig = sig; 1950 /* 1951 * Log signals which would cause core dumps 1952 * (Log as LOG_INFO to appease those who don't want 1953 * these messages.) 1954 * XXX : Todo, as well as euid, write out ruid too 1955 */ 1956 if (coredump(lp, sig) == 0) 1957 sig |= WCOREFLAG; 1958 if (kern_logsigexit) 1959 log(LOG_INFO, 1960 "pid %d (%s), uid %d: exited on signal %d%s\n", 1961 p->p_pid, p->p_comm, 1962 p->p_ucred ? p->p_ucred->cr_uid : -1, 1963 sig &~ WCOREFLAG, 1964 sig & WCOREFLAG ? " (core dumped)" : ""); 1965 } 1966 exit1(W_EXITCODE(0, sig)); 1967 /* NOTREACHED */ 1968 } 1969 1970 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1971 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1972 sizeof(corefilename), "process corefile name format string"); 1973 1974 /* 1975 * expand_name(name, uid, pid) 1976 * Expand the name described in corefilename, using name, uid, and pid. 1977 * corefilename is a kprintf-like string, with three format specifiers: 1978 * %N name of process ("name") 1979 * %P process id (pid) 1980 * %U user id (uid) 1981 * For example, "%N.core" is the default; they can be disabled completely 1982 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1983 * This is controlled by the sysctl variable kern.corefile (see above). 1984 */ 1985 1986 static char * 1987 expand_name(const char *name, uid_t uid, pid_t pid) 1988 { 1989 char *temp; 1990 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1991 int i, n; 1992 char *format = corefilename; 1993 size_t namelen; 1994 1995 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1996 if (temp == NULL) 1997 return NULL; 1998 namelen = strlen(name); 1999 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2000 int l; 2001 switch (format[i]) { 2002 case '%': /* Format character */ 2003 i++; 2004 switch (format[i]) { 2005 case '%': 2006 temp[n++] = '%'; 2007 break; 2008 case 'N': /* process name */ 2009 if ((n + namelen) > MAXPATHLEN) { 2010 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2011 pid, name, uid, temp, name); 2012 kfree(temp, M_TEMP); 2013 return NULL; 2014 } 2015 memcpy(temp+n, name, namelen); 2016 n += namelen; 2017 break; 2018 case 'P': /* process id */ 2019 l = ksprintf(buf, "%u", pid); 2020 if ((n + l) > MAXPATHLEN) { 2021 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2022 pid, name, uid, temp, name); 2023 kfree(temp, M_TEMP); 2024 return NULL; 2025 } 2026 memcpy(temp+n, buf, l); 2027 n += l; 2028 break; 2029 case 'U': /* user id */ 2030 l = ksprintf(buf, "%u", uid); 2031 if ((n + l) > MAXPATHLEN) { 2032 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2033 pid, name, uid, temp, name); 2034 kfree(temp, M_TEMP); 2035 return NULL; 2036 } 2037 memcpy(temp+n, buf, l); 2038 n += l; 2039 break; 2040 default: 2041 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2042 } 2043 break; 2044 default: 2045 temp[n++] = format[i]; 2046 } 2047 } 2048 temp[n] = '\0'; 2049 return temp; 2050 } 2051 2052 /* 2053 * Dump a process' core. The main routine does some 2054 * policy checking, and creates the name of the coredump; 2055 * then it passes on a vnode and a size limit to the process-specific 2056 * coredump routine if there is one; if there _is not_ one, it returns 2057 * ENOSYS; otherwise it returns the error from the process-specific routine. 2058 * 2059 * The parameter `lp' is the lwp which triggered the coredump. 2060 */ 2061 2062 static int 2063 coredump(struct lwp *lp, int sig) 2064 { 2065 struct proc *p = lp->lwp_proc; 2066 struct vnode *vp; 2067 struct ucred *cred = p->p_ucred; 2068 struct flock lf; 2069 struct nlookupdata nd; 2070 struct vattr vattr; 2071 int error, error1; 2072 char *name; /* name of corefile */ 2073 off_t limit; 2074 2075 STOPEVENT(p, S_CORE, 0); 2076 2077 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2078 return (EFAULT); 2079 2080 /* 2081 * Note that the bulk of limit checking is done after 2082 * the corefile is created. The exception is if the limit 2083 * for corefiles is 0, in which case we don't bother 2084 * creating the corefile at all. This layout means that 2085 * a corefile is truncated instead of not being created, 2086 * if it is larger than the limit. 2087 */ 2088 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2089 if (limit == 0) 2090 return EFBIG; 2091 2092 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2093 if (name == NULL) 2094 return (EINVAL); 2095 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2096 if (error == 0) 2097 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2098 kfree(name, M_TEMP); 2099 if (error) { 2100 nlookup_done(&nd); 2101 return (error); 2102 } 2103 vp = nd.nl_open_vp; 2104 nd.nl_open_vp = NULL; 2105 nlookup_done(&nd); 2106 2107 vn_unlock(vp); 2108 lf.l_whence = SEEK_SET; 2109 lf.l_start = 0; 2110 lf.l_len = 0; 2111 lf.l_type = F_WRLCK; 2112 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2113 if (error) 2114 goto out2; 2115 2116 /* Don't dump to non-regular files or files with links. */ 2117 if (vp->v_type != VREG || 2118 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2119 error = EFAULT; 2120 goto out1; 2121 } 2122 2123 /* Don't dump to files current user does not own */ 2124 if (vattr.va_uid != p->p_ucred->cr_uid) { 2125 error = EFAULT; 2126 goto out1; 2127 } 2128 2129 VATTR_NULL(&vattr); 2130 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2131 vattr.va_size = 0; 2132 VOP_SETATTR(vp, &vattr, cred); 2133 p->p_acflag |= ACORE; 2134 vn_unlock(vp); 2135 2136 error = p->p_sysent->sv_coredump ? 2137 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2138 2139 out1: 2140 lf.l_type = F_UNLCK; 2141 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2142 out2: 2143 error1 = vn_close(vp, FWRITE); 2144 if (error == 0) 2145 error = error1; 2146 return (error); 2147 } 2148 2149 /* 2150 * Nonexistent system call-- signal process (may want to handle it). 2151 * Flag error in case process won't see signal immediately (blocked or ignored). 2152 * 2153 * MPALMOSTSAFE 2154 */ 2155 /* ARGSUSED */ 2156 int 2157 sys_nosys(struct nosys_args *args) 2158 { 2159 get_mplock(); 2160 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2161 rel_mplock(); 2162 return (EINVAL); 2163 } 2164 2165 /* 2166 * Send a SIGIO or SIGURG signal to a process or process group using 2167 * stored credentials rather than those of the current process. 2168 */ 2169 void 2170 pgsigio(struct sigio *sigio, int sig, int checkctty) 2171 { 2172 if (sigio == NULL) 2173 return; 2174 2175 if (sigio->sio_pgid > 0) { 2176 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2177 sigio->sio_proc)) 2178 ksignal(sigio->sio_proc, sig); 2179 } else if (sigio->sio_pgid < 0) { 2180 struct proc *p; 2181 2182 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2183 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2184 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2185 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2186 ksignal(p, sig); 2187 } 2188 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2189 } 2190 } 2191 2192 static int 2193 filt_sigattach(struct knote *kn) 2194 { 2195 struct proc *p = curproc; 2196 2197 kn->kn_ptr.p_proc = p; 2198 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2199 2200 /* XXX lock the proc here while adding to the list? */ 2201 knote_insert(&p->p_klist, kn); 2202 2203 return (0); 2204 } 2205 2206 static void 2207 filt_sigdetach(struct knote *kn) 2208 { 2209 struct proc *p = kn->kn_ptr.p_proc; 2210 2211 knote_remove(&p->p_klist, kn); 2212 } 2213 2214 /* 2215 * signal knotes are shared with proc knotes, so we apply a mask to 2216 * the hint in order to differentiate them from process hints. This 2217 * could be avoided by using a signal-specific knote list, but probably 2218 * isn't worth the trouble. 2219 */ 2220 static int 2221 filt_signal(struct knote *kn, long hint) 2222 { 2223 if (hint & NOTE_SIGNAL) { 2224 hint &= ~NOTE_SIGNAL; 2225 2226 if (kn->kn_id == hint) 2227 kn->kn_data++; 2228 } 2229 return (kn->kn_data != 0); 2230 } 2231