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 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/sysproto.h> 48 #include <sys/signalvar.h> 49 #include <sys/resourcevar.h> 50 #include <sys/vnode.h> 51 #include <sys/event.h> 52 #include <sys/proc.h> 53 #include <sys/nlookup.h> 54 #include <sys/pioctl.h> 55 #include <sys/systm.h> 56 #include <sys/acct.h> 57 #include <sys/fcntl.h> 58 #include <sys/lock.h> 59 #include <sys/wait.h> 60 #include <sys/ktrace.h> 61 #include <sys/syslog.h> 62 #include <sys/stat.h> 63 #include <sys/sysent.h> 64 #include <sys/sysctl.h> 65 #include <sys/malloc.h> 66 #include <sys/interrupt.h> 67 #include <sys/unistd.h> 68 #include <sys/kern_syscall.h> 69 #include <sys/vkernel.h> 70 71 #include <sys/signal2.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 static void lwp_signotify(struct lwp *lp); 83 #ifdef SMP 84 static void signotify_remote(void *arg); 85 #endif 86 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 87 struct timespec *timeout); 88 89 static int filt_sigattach(struct knote *kn); 90 static void filt_sigdetach(struct knote *kn); 91 static int filt_signal(struct knote *kn, long hint); 92 93 struct filterops sig_filtops = 94 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 95 96 static int kern_logsigexit = 1; 97 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 98 &kern_logsigexit, 0, 99 "Log processes quitting on abnormal signals to syslog(3)"); 100 101 /* 102 * Can process p, with pcred pc, send the signal sig to process q? 103 */ 104 #define CANSIGNAL(q, sig) \ 105 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 106 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 107 108 /* 109 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 110 */ 111 #define CANSIGIO(ruid, uc, q) \ 112 ((uc)->cr_uid == 0 || \ 113 (ruid) == (q)->p_ucred->cr_ruid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 115 (ruid) == (q)->p_ucred->cr_uid || \ 116 (uc)->cr_uid == (q)->p_ucred->cr_uid) 117 118 int sugid_coredump; 119 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 120 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 121 122 static int do_coredump = 1; 123 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 124 &do_coredump, 0, "Enable/Disable coredumps"); 125 126 /* 127 * Signal properties and actions. 128 * The array below categorizes the signals and their default actions 129 * according to the following properties: 130 */ 131 #define SA_KILL 0x01 /* terminates process by default */ 132 #define SA_CORE 0x02 /* ditto and coredumps */ 133 #define SA_STOP 0x04 /* suspend process */ 134 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 135 #define SA_IGNORE 0x10 /* ignore by default */ 136 #define SA_CONT 0x20 /* continue if suspended */ 137 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 138 #define SA_CKPT 0x80 /* checkpoint process */ 139 140 141 static int sigproptbl[NSIG] = { 142 SA_KILL, /* SIGHUP */ 143 SA_KILL, /* SIGINT */ 144 SA_KILL|SA_CORE, /* SIGQUIT */ 145 SA_KILL|SA_CORE, /* SIGILL */ 146 SA_KILL|SA_CORE, /* SIGTRAP */ 147 SA_KILL|SA_CORE, /* SIGABRT */ 148 SA_KILL|SA_CORE, /* SIGEMT */ 149 SA_KILL|SA_CORE, /* SIGFPE */ 150 SA_KILL, /* SIGKILL */ 151 SA_KILL|SA_CORE, /* SIGBUS */ 152 SA_KILL|SA_CORE, /* SIGSEGV */ 153 SA_KILL|SA_CORE, /* SIGSYS */ 154 SA_KILL, /* SIGPIPE */ 155 SA_KILL, /* SIGALRM */ 156 SA_KILL, /* SIGTERM */ 157 SA_IGNORE, /* SIGURG */ 158 SA_STOP, /* SIGSTOP */ 159 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 160 SA_IGNORE|SA_CONT, /* SIGCONT */ 161 SA_IGNORE, /* SIGCHLD */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 163 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 164 SA_IGNORE, /* SIGIO */ 165 SA_KILL, /* SIGXCPU */ 166 SA_KILL, /* SIGXFSZ */ 167 SA_KILL, /* SIGVTALRM */ 168 SA_KILL, /* SIGPROF */ 169 SA_IGNORE, /* SIGWINCH */ 170 SA_IGNORE, /* SIGINFO */ 171 SA_KILL, /* SIGUSR1 */ 172 SA_KILL, /* SIGUSR2 */ 173 SA_IGNORE, /* SIGTHR */ 174 SA_CKPT, /* SIGCKPT */ 175 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 206 207 }; 208 209 static __inline int 210 sigprop(int sig) 211 { 212 213 if (sig > 0 && sig < NSIG) 214 return (sigproptbl[_SIG_IDX(sig)]); 215 return (0); 216 } 217 218 static __inline int 219 sig_ffs(sigset_t *set) 220 { 221 int i; 222 223 for (i = 0; i < _SIG_WORDS; i++) 224 if (set->__bits[i]) 225 return (ffs(set->__bits[i]) + (i * 32)); 226 return (0); 227 } 228 229 /* 230 * No requirements. 231 */ 232 int 233 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 234 { 235 struct thread *td = curthread; 236 struct proc *p = td->td_proc; 237 struct lwp *lp; 238 struct sigacts *ps = p->p_sigacts; 239 240 if (sig <= 0 || sig > _SIG_MAXSIG) 241 return (EINVAL); 242 243 lwkt_gettoken(&proc_token); 244 245 if (oact) { 246 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 247 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 248 oact->sa_flags = 0; 249 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 250 oact->sa_flags |= SA_ONSTACK; 251 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 252 oact->sa_flags |= SA_RESTART; 253 if (SIGISMEMBER(ps->ps_sigreset, sig)) 254 oact->sa_flags |= SA_RESETHAND; 255 if (SIGISMEMBER(ps->ps_signodefer, sig)) 256 oact->sa_flags |= SA_NODEFER; 257 if (SIGISMEMBER(ps->ps_siginfo, sig)) 258 oact->sa_flags |= SA_SIGINFO; 259 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 260 oact->sa_flags |= SA_MAILBOX; 261 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 262 oact->sa_flags |= SA_NOCLDSTOP; 263 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 264 oact->sa_flags |= SA_NOCLDWAIT; 265 } 266 if (act) { 267 /* 268 * Check for invalid requests. KILL and STOP cannot be 269 * caught. 270 */ 271 if (sig == SIGKILL || sig == SIGSTOP) { 272 if (act->sa_handler != SIG_DFL) { 273 lwkt_reltoken(&proc_token); 274 return (EINVAL); 275 } 276 #if 0 277 /* (not needed, SIG_DFL forces action to occur) */ 278 if (act->sa_flags & SA_MAILBOX) 279 return (EINVAL); 280 #endif 281 } 282 283 /* 284 * Change setting atomically. 285 */ 286 crit_enter(); 287 288 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 289 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 290 if (act->sa_flags & SA_SIGINFO) { 291 ps->ps_sigact[_SIG_IDX(sig)] = 292 (__sighandler_t *)act->sa_sigaction; 293 SIGADDSET(ps->ps_siginfo, sig); 294 } else { 295 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 296 SIGDELSET(ps->ps_siginfo, sig); 297 } 298 if (!(act->sa_flags & SA_RESTART)) 299 SIGADDSET(ps->ps_sigintr, sig); 300 else 301 SIGDELSET(ps->ps_sigintr, sig); 302 if (act->sa_flags & SA_ONSTACK) 303 SIGADDSET(ps->ps_sigonstack, sig); 304 else 305 SIGDELSET(ps->ps_sigonstack, sig); 306 if (act->sa_flags & SA_RESETHAND) 307 SIGADDSET(ps->ps_sigreset, sig); 308 else 309 SIGDELSET(ps->ps_sigreset, sig); 310 if (act->sa_flags & SA_NODEFER) 311 SIGADDSET(ps->ps_signodefer, sig); 312 else 313 SIGDELSET(ps->ps_signodefer, sig); 314 if (act->sa_flags & SA_MAILBOX) 315 SIGADDSET(ps->ps_sigmailbox, sig); 316 else 317 SIGDELSET(ps->ps_sigmailbox, sig); 318 if (sig == SIGCHLD) { 319 if (act->sa_flags & SA_NOCLDSTOP) 320 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 321 else 322 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 323 if (act->sa_flags & SA_NOCLDWAIT) { 324 /* 325 * Paranoia: since SA_NOCLDWAIT is implemented 326 * by reparenting the dying child to PID 1 (and 327 * trust it to reap the zombie), PID 1 itself 328 * is forbidden to set SA_NOCLDWAIT. 329 */ 330 if (p->p_pid == 1) 331 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 332 else 333 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 334 } else { 335 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 336 } 337 } 338 /* 339 * Set bit in p_sigignore for signals that are set to SIG_IGN, 340 * and for signals set to SIG_DFL where the default is to 341 * ignore. However, don't put SIGCONT in p_sigignore, as we 342 * have to restart the process. 343 */ 344 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 345 (sigprop(sig) & SA_IGNORE && 346 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 347 /* never to be seen again */ 348 SIGDELSET(p->p_siglist, sig); 349 /* 350 * Remove the signal also from the thread lists. 351 */ 352 FOREACH_LWP_IN_PROC(lp, p) { 353 SIGDELSET(lp->lwp_siglist, sig); 354 } 355 if (sig != SIGCONT) { 356 /* easier in ksignal */ 357 SIGADDSET(p->p_sigignore, sig); 358 } 359 SIGDELSET(p->p_sigcatch, sig); 360 } else { 361 SIGDELSET(p->p_sigignore, sig); 362 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 363 SIGDELSET(p->p_sigcatch, sig); 364 else 365 SIGADDSET(p->p_sigcatch, sig); 366 } 367 368 crit_exit(); 369 } 370 lwkt_reltoken(&proc_token); 371 return (0); 372 } 373 374 int 375 sys_sigaction(struct sigaction_args *uap) 376 { 377 struct sigaction act, oact; 378 struct sigaction *actp, *oactp; 379 int error; 380 381 actp = (uap->act != NULL) ? &act : NULL; 382 oactp = (uap->oact != NULL) ? &oact : NULL; 383 if (actp) { 384 error = copyin(uap->act, actp, sizeof(act)); 385 if (error) 386 return (error); 387 } 388 error = kern_sigaction(uap->sig, actp, oactp); 389 if (oactp && !error) { 390 error = copyout(oactp, uap->oact, sizeof(oact)); 391 } 392 return (error); 393 } 394 395 /* 396 * Initialize signal state for process 0; 397 * set to ignore signals that are ignored by default. 398 */ 399 void 400 siginit(struct proc *p) 401 { 402 int i; 403 404 for (i = 1; i <= NSIG; i++) 405 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 406 SIGADDSET(p->p_sigignore, i); 407 } 408 409 /* 410 * Reset signals for an exec of the specified process. 411 */ 412 void 413 execsigs(struct proc *p) 414 { 415 struct sigacts *ps = p->p_sigacts; 416 struct lwp *lp; 417 int sig; 418 419 lp = ONLY_LWP_IN_PROC(p); 420 421 /* 422 * Reset caught signals. Held signals remain held 423 * through p_sigmask (unless they were caught, 424 * and are now ignored by default). 425 */ 426 while (SIGNOTEMPTY(p->p_sigcatch)) { 427 sig = sig_ffs(&p->p_sigcatch); 428 SIGDELSET(p->p_sigcatch, sig); 429 if (sigprop(sig) & SA_IGNORE) { 430 if (sig != SIGCONT) 431 SIGADDSET(p->p_sigignore, sig); 432 SIGDELSET(p->p_siglist, sig); 433 SIGDELSET(lp->lwp_siglist, sig); 434 } 435 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 436 } 437 438 /* 439 * Reset stack state to the user stack. 440 * Clear set of signals caught on the signal stack. 441 */ 442 lp->lwp_sigstk.ss_flags = SS_DISABLE; 443 lp->lwp_sigstk.ss_size = 0; 444 lp->lwp_sigstk.ss_sp = 0; 445 lp->lwp_flag &= ~LWP_ALTSTACK; 446 /* 447 * Reset no zombies if child dies flag as Solaris does. 448 */ 449 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 450 } 451 452 /* 453 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 454 * 455 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 456 * p == curproc. 457 */ 458 int 459 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 460 { 461 struct thread *td = curthread; 462 struct lwp *lp = td->td_lwp; 463 int error; 464 465 lwkt_gettoken(&proc_token); 466 467 if (oset != NULL) 468 *oset = lp->lwp_sigmask; 469 470 error = 0; 471 if (set != NULL) { 472 switch (how) { 473 case SIG_BLOCK: 474 SIG_CANTMASK(*set); 475 SIGSETOR(lp->lwp_sigmask, *set); 476 break; 477 case SIG_UNBLOCK: 478 SIGSETNAND(lp->lwp_sigmask, *set); 479 break; 480 case SIG_SETMASK: 481 SIG_CANTMASK(*set); 482 lp->lwp_sigmask = *set; 483 break; 484 default: 485 error = EINVAL; 486 break; 487 } 488 } 489 490 lwkt_reltoken(&proc_token); 491 492 return (error); 493 } 494 495 /* 496 * sigprocmask() 497 * 498 * MPSAFE 499 */ 500 int 501 sys_sigprocmask(struct sigprocmask_args *uap) 502 { 503 sigset_t set, oset; 504 sigset_t *setp, *osetp; 505 int error; 506 507 setp = (uap->set != NULL) ? &set : NULL; 508 osetp = (uap->oset != NULL) ? &oset : NULL; 509 if (setp) { 510 error = copyin(uap->set, setp, sizeof(set)); 511 if (error) 512 return (error); 513 } 514 error = kern_sigprocmask(uap->how, setp, osetp); 515 if (osetp && !error) { 516 error = copyout(osetp, uap->oset, sizeof(oset)); 517 } 518 return (error); 519 } 520 521 /* 522 * MPSAFE 523 */ 524 int 525 kern_sigpending(struct __sigset *set) 526 { 527 struct lwp *lp = curthread->td_lwp; 528 529 *set = lwp_sigpend(lp); 530 531 return (0); 532 } 533 534 /* 535 * MPSAFE 536 */ 537 int 538 sys_sigpending(struct sigpending_args *uap) 539 { 540 sigset_t set; 541 int error; 542 543 error = kern_sigpending(&set); 544 545 if (error == 0) 546 error = copyout(&set, uap->set, sizeof(set)); 547 return (error); 548 } 549 550 /* 551 * Suspend process until signal, providing mask to be set 552 * in the meantime. 553 * 554 * MPSAFE 555 */ 556 int 557 kern_sigsuspend(struct __sigset *set) 558 { 559 struct thread *td = curthread; 560 struct lwp *lp = td->td_lwp; 561 struct proc *p = td->td_proc; 562 struct sigacts *ps = p->p_sigacts; 563 564 /* 565 * When returning from sigsuspend, we want 566 * the old mask to be restored after the 567 * signal handler has finished. Thus, we 568 * save it here and mark the sigacts structure 569 * to indicate this. 570 */ 571 lp->lwp_oldsigmask = lp->lwp_sigmask; 572 lp->lwp_flag |= LWP_OLDMASK; 573 574 SIG_CANTMASK(*set); 575 lp->lwp_sigmask = *set; 576 while (tsleep(ps, PCATCH, "pause", 0) == 0) 577 /* void */; 578 /* always return EINTR rather than ERESTART... */ 579 return (EINTR); 580 } 581 582 /* 583 * Note nonstandard calling convention: libc stub passes mask, not 584 * pointer, to save a copyin. 585 * 586 * MPSAFE 587 */ 588 int 589 sys_sigsuspend(struct sigsuspend_args *uap) 590 { 591 sigset_t mask; 592 int error; 593 594 error = copyin(uap->sigmask, &mask, sizeof(mask)); 595 if (error) 596 return (error); 597 598 error = kern_sigsuspend(&mask); 599 600 return (error); 601 } 602 603 /* 604 * MPSAFE 605 */ 606 int 607 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 608 { 609 struct thread *td = curthread; 610 struct lwp *lp = td->td_lwp; 611 struct proc *p = td->td_proc; 612 613 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 614 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 615 616 if (oss) 617 *oss = lp->lwp_sigstk; 618 619 if (ss) { 620 if (ss->ss_flags & SS_DISABLE) { 621 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 622 return (EINVAL); 623 lp->lwp_flag &= ~LWP_ALTSTACK; 624 lp->lwp_sigstk.ss_flags = ss->ss_flags; 625 } else { 626 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 627 return (ENOMEM); 628 lp->lwp_flag |= LWP_ALTSTACK; 629 lp->lwp_sigstk = *ss; 630 } 631 } 632 633 return (0); 634 } 635 636 /* 637 * MPSAFE 638 */ 639 int 640 sys_sigaltstack(struct sigaltstack_args *uap) 641 { 642 stack_t ss, oss; 643 int error; 644 645 if (uap->ss) { 646 error = copyin(uap->ss, &ss, sizeof(ss)); 647 if (error) 648 return (error); 649 } 650 651 error = kern_sigaltstack(uap->ss ? &ss : NULL, 652 uap->oss ? &oss : NULL); 653 654 if (error == 0 && uap->oss) 655 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 656 return (error); 657 } 658 659 /* 660 * Common code for kill process group/broadcast kill. 661 * cp is calling process. 662 */ 663 struct killpg_info { 664 int nfound; 665 int sig; 666 }; 667 668 static int killpg_all_callback(struct proc *p, void *data); 669 670 static int 671 dokillpg(int sig, int pgid, int all) 672 { 673 struct killpg_info info; 674 struct proc *cp = curproc; 675 struct proc *p; 676 struct pgrp *pgrp; 677 678 info.nfound = 0; 679 info.sig = sig; 680 681 if (all) { 682 /* 683 * broadcast 684 */ 685 allproc_scan(killpg_all_callback, &info); 686 } else { 687 if (pgid == 0) { 688 /* 689 * zero pgid means send to my process group. 690 */ 691 pgrp = cp->p_pgrp; 692 } else { 693 pgrp = pgfind(pgid); 694 if (pgrp == NULL) 695 return (ESRCH); 696 } 697 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 698 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 699 if (p->p_pid <= 1 || 700 p->p_stat == SZOMB || 701 (p->p_flag & P_SYSTEM) || 702 !CANSIGNAL(p, sig)) { 703 continue; 704 } 705 ++info.nfound; 706 if (sig) 707 ksignal(p, sig); 708 } 709 lockmgr(&pgrp->pg_lock, LK_RELEASE); 710 } 711 return (info.nfound ? 0 : ESRCH); 712 } 713 714 static int 715 killpg_all_callback(struct proc *p, void *data) 716 { 717 struct killpg_info *info = data; 718 719 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 720 p == curproc || !CANSIGNAL(p, info->sig)) { 721 return (0); 722 } 723 ++info->nfound; 724 if (info->sig) 725 ksignal(p, info->sig); 726 return(0); 727 } 728 729 /* 730 * Send a general signal to a process or LWPs within that process. Note 731 * that new signals cannot be sent if a process is exiting. 732 * 733 * No requirements. 734 */ 735 int 736 kern_kill(int sig, pid_t pid, lwpid_t tid) 737 { 738 int t; 739 740 if ((u_int)sig > _SIG_MAXSIG) 741 return (EINVAL); 742 743 lwkt_gettoken(&proc_token); 744 745 if (pid > 0) { 746 struct proc *p; 747 struct lwp *lp = NULL; 748 749 /* kill single process */ 750 if ((p = pfind(pid)) == NULL) { 751 lwkt_reltoken(&proc_token); 752 return (ESRCH); 753 } 754 if (!CANSIGNAL(p, sig)) { 755 lwkt_reltoken(&proc_token); 756 return (EPERM); 757 } 758 759 /* 760 * NOP if the process is exiting. Note that lwpsignal() is 761 * called directly with P_WEXIT set to kill individual LWPs 762 * during exit, which is allowed. 763 */ 764 if (p->p_flag & P_WEXIT) { 765 lwkt_reltoken(&proc_token); 766 return (0); 767 } 768 if (tid != -1) { 769 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 770 if (lp == NULL) { 771 lwkt_reltoken(&proc_token); 772 return (ESRCH); 773 } 774 } 775 if (sig) 776 lwpsignal(p, lp, sig); 777 lwkt_reltoken(&proc_token); 778 return (0); 779 } 780 /* 781 * If we come here, pid is a special broadcast pid. 782 * This doesn't mix with a tid. 783 */ 784 if (tid != -1) { 785 lwkt_reltoken(&proc_token); 786 return (EINVAL); 787 } 788 switch (pid) { 789 case -1: /* broadcast signal */ 790 t = (dokillpg(sig, 0, 1)); 791 break; 792 case 0: /* signal own process group */ 793 t = (dokillpg(sig, 0, 0)); 794 break; 795 default: /* negative explicit process group */ 796 t = (dokillpg(sig, -pid, 0)); 797 break; 798 } 799 lwkt_reltoken(&proc_token); 800 return t; 801 } 802 803 int 804 sys_kill(struct kill_args *uap) 805 { 806 int error; 807 808 error = kern_kill(uap->signum, uap->pid, -1); 809 return (error); 810 } 811 812 int 813 sys_lwp_kill(struct lwp_kill_args *uap) 814 { 815 int error; 816 pid_t pid = uap->pid; 817 818 /* 819 * A tid is mandatory for lwp_kill(), otherwise 820 * you could simply use kill(). 821 */ 822 if (uap->tid == -1) 823 return (EINVAL); 824 825 /* 826 * To save on a getpid() function call for intra-process 827 * signals, pid == -1 means current process. 828 */ 829 if (pid == -1) 830 pid = curproc->p_pid; 831 832 error = kern_kill(uap->signum, pid, uap->tid); 833 return (error); 834 } 835 836 /* 837 * Send a signal to a process group. 838 */ 839 void 840 gsignal(int pgid, int sig) 841 { 842 struct pgrp *pgrp; 843 844 if (pgid && (pgrp = pgfind(pgid))) 845 pgsignal(pgrp, sig, 0); 846 } 847 848 /* 849 * Send a signal to a process group. If checktty is 1, 850 * limit to members which have a controlling terminal. 851 * 852 * pg_lock interlocks against a fork that might be in progress, to 853 * ensure that the new child process picks up the signal. 854 */ 855 void 856 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 857 { 858 struct proc *p; 859 860 if (pgrp) { 861 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 862 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 863 if (checkctty == 0 || p->p_flag & P_CONTROLT) 864 ksignal(p, sig); 865 } 866 lockmgr(&pgrp->pg_lock, LK_RELEASE); 867 } 868 } 869 870 /* 871 * Send a signal caused by a trap to the current lwp. If it will be caught 872 * immediately, deliver it with correct code. Otherwise, post it normally. 873 * 874 * These signals may ONLY be delivered to the specified lwp and may never 875 * be delivered to the process generically. 876 */ 877 void 878 trapsignal(struct lwp *lp, int sig, u_long code) 879 { 880 struct proc *p = lp->lwp_proc; 881 struct sigacts *ps = p->p_sigacts; 882 883 /* 884 * If we are a virtual kernel running an emulated user process 885 * context, switch back to the virtual kernel context before 886 * trying to post the signal. 887 */ 888 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 889 struct trapframe *tf = lp->lwp_md.md_regs; 890 tf->tf_trapno = 0; 891 vkernel_trap(lp, tf); 892 } 893 894 895 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 896 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 897 lp->lwp_ru.ru_nsignals++; 898 #ifdef KTRACE 899 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 900 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 901 &lp->lwp_sigmask, code); 902 #endif 903 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 904 &lp->lwp_sigmask, code); 905 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 906 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 907 SIGADDSET(lp->lwp_sigmask, sig); 908 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 909 /* 910 * See kern_sigaction() for origin of this code. 911 */ 912 SIGDELSET(p->p_sigcatch, sig); 913 if (sig != SIGCONT && 914 sigprop(sig) & SA_IGNORE) 915 SIGADDSET(p->p_sigignore, sig); 916 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 917 } 918 } else { 919 lp->lwp_code = code; /* XXX for core dump/debugger */ 920 lp->lwp_sig = sig; /* XXX to verify code */ 921 lwpsignal(p, lp, sig); 922 } 923 } 924 925 /* 926 * Find a suitable lwp to deliver the signal to. 927 * 928 * Returns NULL if all lwps hold the signal blocked. 929 */ 930 static struct lwp * 931 find_lwp_for_signal(struct proc *p, int sig) 932 { 933 struct lwp *lp; 934 struct lwp *run, *sleep, *stop; 935 936 /* 937 * If the running/preempted thread belongs to the proc to which 938 * the signal is being delivered and this thread does not block 939 * the signal, then we can avoid a context switch by delivering 940 * the signal to this thread, because it will return to userland 941 * soon anyways. 942 */ 943 lp = lwkt_preempted_proc(); 944 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig)) 945 return (lp); 946 947 run = sleep = stop = NULL; 948 FOREACH_LWP_IN_PROC(lp, p) { 949 /* 950 * If the signal is being blocked by the lwp, then this 951 * lwp is not eligible for receiving the signal. 952 */ 953 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 954 continue; 955 956 switch (lp->lwp_stat) { 957 case LSRUN: 958 run = lp; 959 break; 960 961 case LSSTOP: 962 stop = lp; 963 break; 964 965 case LSSLEEP: 966 if (lp->lwp_flag & LWP_SINTR) 967 sleep = lp; 968 break; 969 } 970 } 971 972 if (run != NULL) 973 return (run); 974 else if (sleep != NULL) 975 return (sleep); 976 else 977 return (stop); 978 } 979 980 /* 981 * Send the signal to the process. If the signal has an action, the action 982 * is usually performed by the target process rather than the caller; we add 983 * the signal to the set of pending signals for the process. 984 * 985 * Exceptions: 986 * o When a stop signal is sent to a sleeping process that takes the 987 * default action, the process is stopped without awakening it. 988 * o SIGCONT restarts stopped processes (or puts them back to sleep) 989 * regardless of the signal action (eg, blocked or ignored). 990 * 991 * Other ignored signals are discarded immediately. 992 * 993 * No requirements. 994 */ 995 void 996 ksignal(struct proc *p, int sig) 997 { 998 lwpsignal(p, NULL, sig); 999 } 1000 1001 /* 1002 * The core for ksignal. lp may be NULL, then a suitable thread 1003 * will be chosen. If not, lp MUST be a member of p. 1004 * 1005 * No requirements. 1006 */ 1007 void 1008 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1009 { 1010 int prop; 1011 sig_t action; 1012 1013 if (sig > _SIG_MAXSIG || sig <= 0) { 1014 kprintf("lwpsignal: signal %d\n", sig); 1015 panic("lwpsignal signal number"); 1016 } 1017 1018 KKASSERT(lp == NULL || lp->lwp_proc == p); 1019 1020 lwkt_gettoken(&proc_token); 1021 1022 prop = sigprop(sig); 1023 1024 /* 1025 * If proc is traced, always give parent a chance; 1026 * if signal event is tracked by procfs, give *that* 1027 * a chance, as well. 1028 */ 1029 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1030 action = SIG_DFL; 1031 } else { 1032 /* 1033 * Do not try to deliver signals to an exiting lwp. Note 1034 * that we must still deliver the signal if P_WEXIT is set 1035 * in the process flags. 1036 */ 1037 if (lp && (lp->lwp_flag & LWP_WEXIT)) { 1038 lwkt_reltoken(&proc_token); 1039 return; 1040 } 1041 1042 /* 1043 * If the signal is being ignored, then we forget about 1044 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1045 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1046 */ 1047 if (SIGISMEMBER(p->p_sigignore, sig)) { 1048 lwkt_reltoken(&proc_token); 1049 return; 1050 } 1051 if (SIGISMEMBER(p->p_sigcatch, sig)) 1052 action = SIG_CATCH; 1053 else 1054 action = SIG_DFL; 1055 } 1056 1057 /* 1058 * If continuing, clear any pending STOP signals. 1059 */ 1060 if (prop & SA_CONT) 1061 SIG_STOPSIGMASK(p->p_siglist); 1062 1063 if (prop & SA_STOP) { 1064 /* 1065 * If sending a tty stop signal to a member of an orphaned 1066 * process group, discard the signal here if the action 1067 * is default; don't stop the process below if sleeping, 1068 * and don't clear any pending SIGCONT. 1069 */ 1070 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1071 action == SIG_DFL) { 1072 lwkt_reltoken(&proc_token); 1073 return; 1074 } 1075 SIG_CONTSIGMASK(p->p_siglist); 1076 p->p_flag &= ~P_CONTINUED; 1077 } 1078 1079 crit_enter(); 1080 1081 if (p->p_stat == SSTOP) { 1082 /* 1083 * Nobody can handle this signal, add it to the lwp or 1084 * process pending list 1085 */ 1086 if (lp) 1087 SIGADDSET(lp->lwp_siglist, sig); 1088 else 1089 SIGADDSET(p->p_siglist, sig); 1090 1091 /* 1092 * If the process is stopped and is being traced, then no 1093 * further action is necessary. 1094 */ 1095 if (p->p_flag & P_TRACED) 1096 goto out; 1097 1098 /* 1099 * If the process is stopped and receives a KILL signal, 1100 * make the process runnable. 1101 */ 1102 if (sig == SIGKILL) { 1103 proc_unstop(p); 1104 goto active_process; 1105 } 1106 1107 /* 1108 * If the process is stopped and receives a CONT signal, 1109 * then try to make the process runnable again. 1110 */ 1111 if (prop & SA_CONT) { 1112 /* 1113 * If SIGCONT is default (or ignored), we continue the 1114 * process but don't leave the signal in p_siglist, as 1115 * it has no further action. If SIGCONT is held, we 1116 * continue the process and leave the signal in 1117 * p_siglist. If the process catches SIGCONT, let it 1118 * handle the signal itself. 1119 */ 1120 /* XXX what if the signal is being held blocked? */ 1121 p->p_flag |= P_CONTINUED; 1122 wakeup(p->p_pptr); 1123 if (action == SIG_DFL) 1124 SIGDELSET(p->p_siglist, sig); 1125 proc_unstop(p); 1126 if (action == SIG_CATCH) 1127 goto active_process; 1128 goto out; 1129 } 1130 1131 /* 1132 * If the process is stopped and receives another STOP 1133 * signal, we do not need to stop it again. If we did 1134 * the shell could get confused. 1135 * 1136 * However, if the current/preempted lwp is part of the 1137 * process receiving the signal, we need to keep it, 1138 * so that this lwp can stop in issignal() later, as 1139 * we don't want to wait until it reaches userret! 1140 */ 1141 if (prop & SA_STOP) { 1142 if (lwkt_preempted_proc() == NULL || 1143 lwkt_preempted_proc()->lwp_proc != p) 1144 SIGDELSET(p->p_siglist, sig); 1145 } 1146 1147 /* 1148 * Otherwise the process is stopped and it received some 1149 * signal, which does not change its stopped state. 1150 * 1151 * We have to select one thread to set LWP_BREAKTSLEEP, 1152 * so that the current signal will break the sleep 1153 * as soon as a SA_CONT signal will unstop the process. 1154 */ 1155 if (lp == NULL) 1156 lp = find_lwp_for_signal(p, sig); 1157 if (lp != NULL && 1158 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1159 lp->lwp_flag |= LWP_BREAKTSLEEP; 1160 goto out; 1161 1162 /* NOTREACHED */ 1163 } 1164 /* else not stopped */ 1165 active_process: 1166 1167 /* 1168 * Never deliver a lwp-specific signal to a random lwp. 1169 */ 1170 if (lp == NULL) { 1171 lp = find_lwp_for_signal(p, sig); 1172 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1173 lp = NULL; 1174 } 1175 1176 /* 1177 * Deliver to the process generically if (1) the signal is being 1178 * sent to any thread or (2) we could not find a thread to deliver 1179 * it to. 1180 */ 1181 if (lp == NULL) { 1182 SIGADDSET(p->p_siglist, sig); 1183 goto out; 1184 } 1185 1186 /* 1187 * Deliver to a specific LWP whether it masks it or not. It will 1188 * not be dispatched if masked but we must still deliver it. 1189 */ 1190 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1191 (p->p_flag & P_TRACED) == 0) { 1192 p->p_nice = NZERO; 1193 } 1194 1195 /* 1196 * If the process receives a STOP signal which indeed needs to 1197 * stop the process, do so. If the process chose to catch the 1198 * signal, it will be treated like any other signal. 1199 */ 1200 if ((prop & SA_STOP) && action == SIG_DFL) { 1201 /* 1202 * If a child holding parent blocked, stopping 1203 * could cause deadlock. Take no action at this 1204 * time. 1205 */ 1206 if (p->p_flag & P_PPWAIT) { 1207 SIGADDSET(p->p_siglist, sig); 1208 goto out; 1209 } 1210 1211 /* 1212 * Do not actually try to manipulate the process, but simply 1213 * stop it. Lwps will stop as soon as they safely can. 1214 */ 1215 p->p_xstat = sig; 1216 proc_stop(p); 1217 goto out; 1218 } 1219 1220 /* 1221 * If it is a CONT signal with default action, just ignore it. 1222 */ 1223 if ((prop & SA_CONT) && action == SIG_DFL) 1224 goto out; 1225 1226 /* 1227 * Mark signal pending at this specific thread. 1228 */ 1229 SIGADDSET(lp->lwp_siglist, sig); 1230 1231 lwp_signotify(lp); 1232 1233 out: 1234 lwkt_reltoken(&proc_token); 1235 crit_exit(); 1236 } 1237 1238 /* 1239 * proc_token must be held 1240 */ 1241 static void 1242 lwp_signotify(struct lwp *lp) 1243 { 1244 ASSERT_LWKT_TOKEN_HELD(&proc_token); 1245 crit_enter(); 1246 1247 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1248 /* 1249 * Thread is in tsleep. 1250 */ 1251 1252 /* 1253 * If the thread is sleeping uninterruptibly 1254 * we can't interrupt the sleep... the signal will 1255 * be noticed when the lwp returns through 1256 * trap() or syscall(). 1257 * 1258 * Otherwise the signal can interrupt the sleep. 1259 * 1260 * If the process is traced, the lwp will handle the 1261 * tracing in issignal() when it returns to userland. 1262 */ 1263 if (lp->lwp_flag & LWP_SINTR) { 1264 /* 1265 * Make runnable and break out of any tsleep as well. 1266 */ 1267 lp->lwp_flag |= LWP_BREAKTSLEEP; 1268 setrunnable(lp); 1269 } 1270 } else { 1271 /* 1272 * Otherwise the thread is running 1273 * 1274 * LSRUN does nothing with the signal, other than kicking 1275 * ourselves if we are running. 1276 * SZOMB and SIDL mean that it will either never be noticed, 1277 * or noticed very soon. 1278 * 1279 * Note that lwp_thread may be NULL or may not be completely 1280 * initialized if the process is in the SIDL or SZOMB state. 1281 * 1282 * For SMP we may have to forward the request to another cpu. 1283 * YYY the MP lock prevents the target process from moving 1284 * to another cpu, see kern/kern_switch.c 1285 * 1286 * If the target thread is waiting on its message port, 1287 * wakeup the target thread so it can check (or ignore) 1288 * the new signal. YYY needs cleanup. 1289 */ 1290 if (lp == lwkt_preempted_proc()) { 1291 signotify(); 1292 } else if (lp->lwp_stat == LSRUN) { 1293 struct thread *td = lp->lwp_thread; 1294 struct proc *p __debugvar = lp->lwp_proc; 1295 1296 KASSERT(td != NULL, 1297 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1298 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1299 p->p_flag, lp->lwp_flag)); 1300 1301 /* 1302 * To prevent a MP race with TDF_SINTR we must 1303 * schedule the thread on the correct cpu. 1304 */ 1305 #ifdef SMP 1306 if (td->td_gd != mycpu) { 1307 LWPHOLD(lp); 1308 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1309 } else 1310 #endif 1311 if (td->td_flags & TDF_SINTR) 1312 lwkt_schedule(td); 1313 } 1314 } 1315 crit_exit(); 1316 } 1317 1318 #ifdef SMP 1319 1320 /* 1321 * This function is called via an IPI. We will be in a critical section but 1322 * the MP lock will NOT be held. Also note that by the time the ipi message 1323 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1324 */ 1325 static void 1326 signotify_remote(void *arg) 1327 { 1328 struct lwp *lp = arg; 1329 1330 if (lp == lwkt_preempted_proc()) { 1331 signotify(); 1332 } else { 1333 struct thread *td = lp->lwp_thread; 1334 if (td->td_flags & TDF_SINTR) 1335 lwkt_schedule(td); 1336 } 1337 LWPRELE(lp); 1338 } 1339 1340 #endif 1341 1342 /* 1343 * Caller must hold proc_token 1344 */ 1345 void 1346 proc_stop(struct proc *p) 1347 { 1348 struct lwp *lp; 1349 1350 ASSERT_LWKT_TOKEN_HELD(&proc_token); 1351 crit_enter(); 1352 1353 /* If somebody raced us, be happy with it */ 1354 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1355 crit_exit(); 1356 return; 1357 } 1358 p->p_stat = SSTOP; 1359 1360 FOREACH_LWP_IN_PROC(lp, p) { 1361 switch (lp->lwp_stat) { 1362 case LSSTOP: 1363 /* 1364 * Do nothing, we are already counted in 1365 * p_nstopped. 1366 */ 1367 break; 1368 1369 case LSSLEEP: 1370 /* 1371 * We're sleeping, but we will stop before 1372 * returning to userspace, so count us 1373 * as stopped as well. We set LWP_WSTOP 1374 * to signal the lwp that it should not 1375 * increase p_nstopped when reaching tstop(). 1376 */ 1377 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1378 lp->lwp_flag |= LWP_WSTOP; 1379 ++p->p_nstopped; 1380 } 1381 break; 1382 1383 case LSRUN: 1384 /* 1385 * We might notify ourself, but that's not 1386 * a problem. 1387 */ 1388 lwp_signotify(lp); 1389 break; 1390 } 1391 } 1392 1393 if (p->p_nstopped == p->p_nthreads) { 1394 p->p_flag &= ~P_WAITED; 1395 wakeup(p->p_pptr); 1396 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1397 ksignal(p->p_pptr, SIGCHLD); 1398 } 1399 crit_exit(); 1400 } 1401 1402 /* 1403 * Caller must hold proc_token 1404 */ 1405 void 1406 proc_unstop(struct proc *p) 1407 { 1408 struct lwp *lp; 1409 1410 ASSERT_LWKT_TOKEN_HELD(&proc_token); 1411 crit_enter(); 1412 1413 if (p->p_stat != SSTOP) { 1414 crit_exit(); 1415 return; 1416 } 1417 1418 p->p_stat = SACTIVE; 1419 1420 FOREACH_LWP_IN_PROC(lp, p) { 1421 switch (lp->lwp_stat) { 1422 case LSRUN: 1423 /* 1424 * Uh? Not stopped? Well, I guess that's okay. 1425 */ 1426 if (bootverbose) 1427 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1428 p->p_pid, lp->lwp_tid); 1429 break; 1430 1431 case LSSLEEP: 1432 /* 1433 * Still sleeping. Don't bother waking it up. 1434 * However, if this thread was counted as 1435 * stopped, undo this. 1436 * 1437 * Nevertheless we call setrunnable() so that it 1438 * will wake up in case a signal or timeout arrived 1439 * in the meantime. 1440 */ 1441 if (lp->lwp_flag & LWP_WSTOP) { 1442 lp->lwp_flag &= ~LWP_WSTOP; 1443 --p->p_nstopped; 1444 } else { 1445 if (bootverbose) 1446 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1447 p->p_pid, lp->lwp_tid); 1448 } 1449 /* FALLTHROUGH */ 1450 1451 case LSSTOP: 1452 setrunnable(lp); 1453 break; 1454 1455 } 1456 } 1457 crit_exit(); 1458 } 1459 1460 /* 1461 * No requirements. 1462 */ 1463 static int 1464 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1465 { 1466 sigset_t savedmask, set; 1467 struct proc *p = curproc; 1468 struct lwp *lp = curthread->td_lwp; 1469 int error, sig, hz, timevalid = 0; 1470 struct timespec rts, ets, ts; 1471 struct timeval tv; 1472 1473 lwkt_gettoken(&proc_token); 1474 1475 error = 0; 1476 sig = 0; 1477 ets.tv_sec = 0; /* silence compiler warning */ 1478 ets.tv_nsec = 0; /* silence compiler warning */ 1479 SIG_CANTMASK(waitset); 1480 savedmask = lp->lwp_sigmask; 1481 1482 if (timeout) { 1483 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1484 timeout->tv_nsec < 1000000000) { 1485 timevalid = 1; 1486 getnanouptime(&rts); 1487 ets = rts; 1488 timespecadd(&ets, timeout); 1489 } 1490 } 1491 1492 for (;;) { 1493 set = lwp_sigpend(lp); 1494 SIGSETAND(set, waitset); 1495 if ((sig = sig_ffs(&set)) != 0) { 1496 SIGFILLSET(lp->lwp_sigmask); 1497 SIGDELSET(lp->lwp_sigmask, sig); 1498 SIG_CANTMASK(lp->lwp_sigmask); 1499 sig = issignal(lp, 1); 1500 /* 1501 * It may be a STOP signal, in the case, issignal 1502 * returns 0, because we may stop there, and new 1503 * signal can come in, we should restart if we got 1504 * nothing. 1505 */ 1506 if (sig == 0) 1507 continue; 1508 else 1509 break; 1510 } 1511 1512 /* 1513 * Previous checking got nothing, and we retried but still 1514 * got nothing, we should return the error status. 1515 */ 1516 if (error) 1517 break; 1518 1519 /* 1520 * POSIX says this must be checked after looking for pending 1521 * signals. 1522 */ 1523 if (timeout) { 1524 if (timevalid == 0) { 1525 error = EINVAL; 1526 break; 1527 } 1528 getnanouptime(&rts); 1529 if (timespeccmp(&rts, &ets, >=)) { 1530 error = EAGAIN; 1531 break; 1532 } 1533 ts = ets; 1534 timespecsub(&ts, &rts); 1535 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1536 hz = tvtohz_high(&tv); 1537 } else 1538 hz = 0; 1539 1540 lp->lwp_sigmask = savedmask; 1541 SIGSETNAND(lp->lwp_sigmask, waitset); 1542 /* 1543 * We won't ever be woken up. Instead, our sleep will 1544 * be broken in lwpsignal(). 1545 */ 1546 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1547 if (timeout) { 1548 if (error == ERESTART) { 1549 /* can not restart a timeout wait. */ 1550 error = EINTR; 1551 } else if (error == EAGAIN) { 1552 /* will calculate timeout by ourself. */ 1553 error = 0; 1554 } 1555 } 1556 /* Retry ... */ 1557 } 1558 1559 lp->lwp_sigmask = savedmask; 1560 if (sig) { 1561 error = 0; 1562 bzero(info, sizeof(*info)); 1563 info->si_signo = sig; 1564 lwp_delsig(lp, sig); /* take the signal! */ 1565 1566 if (sig == SIGKILL) { 1567 lwkt_reltoken(&proc_token); 1568 sigexit(lp, sig); 1569 /* NOT REACHED */ 1570 } 1571 } 1572 1573 lwkt_reltoken(&proc_token); 1574 1575 return (error); 1576 } 1577 1578 /* 1579 * MPALMOSTSAFE 1580 */ 1581 int 1582 sys_sigtimedwait(struct sigtimedwait_args *uap) 1583 { 1584 struct timespec ts; 1585 struct timespec *timeout; 1586 sigset_t set; 1587 siginfo_t info; 1588 int error; 1589 1590 if (uap->timeout) { 1591 error = copyin(uap->timeout, &ts, sizeof(ts)); 1592 if (error) 1593 return (error); 1594 timeout = &ts; 1595 } else { 1596 timeout = NULL; 1597 } 1598 error = copyin(uap->set, &set, sizeof(set)); 1599 if (error) 1600 return (error); 1601 error = kern_sigtimedwait(set, &info, timeout); 1602 if (error) 1603 return (error); 1604 if (uap->info) 1605 error = copyout(&info, uap->info, sizeof(info)); 1606 /* Repost if we got an error. */ 1607 /* 1608 * XXX lwp 1609 * 1610 * This could transform a thread-specific signal to another 1611 * thread / process pending signal. 1612 */ 1613 if (error) { 1614 ksignal(curproc, info.si_signo); 1615 } else { 1616 uap->sysmsg_result = info.si_signo; 1617 } 1618 return (error); 1619 } 1620 1621 /* 1622 * MPALMOSTSAFE 1623 */ 1624 int 1625 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1626 { 1627 siginfo_t info; 1628 sigset_t set; 1629 int error; 1630 1631 error = copyin(uap->set, &set, sizeof(set)); 1632 if (error) 1633 return (error); 1634 error = kern_sigtimedwait(set, &info, NULL); 1635 if (error) 1636 return (error); 1637 if (uap->info) 1638 error = copyout(&info, uap->info, sizeof(info)); 1639 /* Repost if we got an error. */ 1640 /* 1641 * XXX lwp 1642 * 1643 * This could transform a thread-specific signal to another 1644 * thread / process pending signal. 1645 */ 1646 if (error) { 1647 ksignal(curproc, info.si_signo); 1648 } else { 1649 uap->sysmsg_result = info.si_signo; 1650 } 1651 return (error); 1652 } 1653 1654 /* 1655 * If the current process has received a signal that would interrupt a 1656 * system call, return EINTR or ERESTART as appropriate. 1657 */ 1658 int 1659 iscaught(struct lwp *lp) 1660 { 1661 struct proc *p = lp->lwp_proc; 1662 int sig; 1663 1664 if (p) { 1665 if ((sig = CURSIG(lp)) != 0) { 1666 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1667 return (EINTR); 1668 return (ERESTART); 1669 } 1670 } 1671 return(EWOULDBLOCK); 1672 } 1673 1674 /* 1675 * If the current process has received a signal (should be caught or cause 1676 * termination, should interrupt current syscall), return the signal number. 1677 * Stop signals with default action are processed immediately, then cleared; 1678 * they aren't returned. This is checked after each entry to the system for 1679 * a syscall or trap (though this can usually be done without calling issignal 1680 * by checking the pending signal masks in the CURSIG macro.) The normal call 1681 * sequence is 1682 * 1683 * This routine is called via CURSIG/__cursig and the MP lock might not be 1684 * held. Obtain the MP lock for the duration of the operation. 1685 * 1686 * while (sig = CURSIG(curproc)) 1687 * postsig(sig); 1688 */ 1689 int 1690 issignal(struct lwp *lp, int maytrace) 1691 { 1692 struct proc *p = lp->lwp_proc; 1693 sigset_t mask; 1694 int sig, prop; 1695 1696 lwkt_gettoken(&proc_token); 1697 1698 for (;;) { 1699 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1700 1701 /* 1702 * If this process is supposed to stop, stop this thread. 1703 */ 1704 if (p->p_stat == SSTOP) 1705 tstop(); 1706 1707 mask = lwp_sigpend(lp); 1708 SIGSETNAND(mask, lp->lwp_sigmask); 1709 if (p->p_flag & P_PPWAIT) 1710 SIG_STOPSIGMASK(mask); 1711 if (SIGISEMPTY(mask)) { /* no signal to send */ 1712 lwkt_reltoken(&proc_token); 1713 return (0); 1714 } 1715 sig = sig_ffs(&mask); 1716 1717 STOPEVENT(p, S_SIG, sig); 1718 1719 /* 1720 * We should see pending but ignored signals 1721 * only if P_TRACED was on when they were posted. 1722 */ 1723 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1724 lwp_delsig(lp, sig); 1725 continue; 1726 } 1727 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1728 /* 1729 * If traced, always stop, and stay stopped until 1730 * released by the parent. 1731 * 1732 * NOTE: SSTOP may get cleared during the loop, 1733 * but we do not re-notify the parent if we have 1734 * to loop several times waiting for the parent 1735 * to let us continue. 1736 * 1737 * XXX not sure if this is still true 1738 */ 1739 p->p_xstat = sig; 1740 proc_stop(p); 1741 do { 1742 tstop(); 1743 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1744 1745 /* 1746 * If parent wants us to take the signal, 1747 * then it will leave it in p->p_xstat; 1748 * otherwise we just look for signals again. 1749 */ 1750 lwp_delsig(lp, sig); /* clear old signal */ 1751 sig = p->p_xstat; 1752 if (sig == 0) 1753 continue; 1754 1755 /* 1756 * Put the new signal into p_siglist. If the 1757 * signal is being masked, look for other signals. 1758 * 1759 * XXX lwp might need a call to ksignal() 1760 */ 1761 SIGADDSET(p->p_siglist, sig); 1762 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1763 continue; 1764 1765 /* 1766 * If the traced bit got turned off, go back up 1767 * to the top to rescan signals. This ensures 1768 * that p_sig* and ps_sigact are consistent. 1769 */ 1770 if ((p->p_flag & P_TRACED) == 0) 1771 continue; 1772 } 1773 1774 prop = sigprop(sig); 1775 1776 /* 1777 * Decide whether the signal should be returned. 1778 * Return the signal's number, or fall through 1779 * to clear it from the pending mask. 1780 */ 1781 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1782 case (intptr_t)SIG_DFL: 1783 /* 1784 * Don't take default actions on system processes. 1785 */ 1786 if (p->p_pid <= 1) { 1787 #ifdef DIAGNOSTIC 1788 /* 1789 * Are you sure you want to ignore SIGSEGV 1790 * in init? XXX 1791 */ 1792 kprintf("Process (pid %lu) got signal %d\n", 1793 (u_long)p->p_pid, sig); 1794 #endif 1795 break; /* == ignore */ 1796 } 1797 1798 /* 1799 * Handle the in-kernel checkpoint action 1800 */ 1801 if (prop & SA_CKPT) { 1802 checkpoint_signal_handler(lp); 1803 break; 1804 } 1805 1806 /* 1807 * If there is a pending stop signal to process 1808 * with default action, stop here, 1809 * then clear the signal. However, 1810 * if process is member of an orphaned 1811 * process group, ignore tty stop signals. 1812 */ 1813 if (prop & SA_STOP) { 1814 if (p->p_flag & P_TRACED || 1815 (p->p_pgrp->pg_jobc == 0 && 1816 prop & SA_TTYSTOP)) 1817 break; /* == ignore */ 1818 p->p_xstat = sig; 1819 proc_stop(p); 1820 tstop(); 1821 break; 1822 } else if (prop & SA_IGNORE) { 1823 /* 1824 * Except for SIGCONT, shouldn't get here. 1825 * Default action is to ignore; drop it. 1826 */ 1827 break; /* == ignore */ 1828 } else { 1829 lwkt_reltoken(&proc_token); 1830 return (sig); 1831 } 1832 1833 /*NOTREACHED*/ 1834 1835 case (intptr_t)SIG_IGN: 1836 /* 1837 * Masking above should prevent us ever trying 1838 * to take action on an ignored signal other 1839 * than SIGCONT, unless process is traced. 1840 */ 1841 if ((prop & SA_CONT) == 0 && 1842 (p->p_flag & P_TRACED) == 0) 1843 kprintf("issignal\n"); 1844 break; /* == ignore */ 1845 1846 default: 1847 /* 1848 * This signal has an action, let 1849 * postsig() process it. 1850 */ 1851 lwkt_reltoken(&proc_token); 1852 return (sig); 1853 } 1854 lwp_delsig(lp, sig); /* take the signal! */ 1855 } 1856 /* NOTREACHED */ 1857 } 1858 1859 /* 1860 * Take the action for the specified signal 1861 * from the current set of pending signals. 1862 */ 1863 void 1864 postsig(int sig) 1865 { 1866 struct lwp *lp = curthread->td_lwp; 1867 struct proc *p = lp->lwp_proc; 1868 struct sigacts *ps = p->p_sigacts; 1869 sig_t action; 1870 sigset_t returnmask; 1871 int code; 1872 1873 KASSERT(sig != 0, ("postsig")); 1874 1875 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1876 1877 /* 1878 * If we are a virtual kernel running an emulated user process 1879 * context, switch back to the virtual kernel context before 1880 * trying to post the signal. 1881 */ 1882 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1883 struct trapframe *tf = lp->lwp_md.md_regs; 1884 tf->tf_trapno = 0; 1885 vkernel_trap(lp, tf); 1886 } 1887 1888 lwp_delsig(lp, sig); 1889 action = ps->ps_sigact[_SIG_IDX(sig)]; 1890 #ifdef KTRACE 1891 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1892 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1893 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1894 #endif 1895 STOPEVENT(p, S_SIG, sig); 1896 1897 if (action == SIG_DFL) { 1898 /* 1899 * Default action, where the default is to kill 1900 * the process. (Other cases were ignored above.) 1901 */ 1902 sigexit(lp, sig); 1903 /* NOTREACHED */ 1904 } else { 1905 /* 1906 * If we get here, the signal must be caught. 1907 */ 1908 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1909 ("postsig action")); 1910 1911 crit_enter(); 1912 1913 /* 1914 * Reset the signal handler if asked to 1915 */ 1916 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1917 /* 1918 * See kern_sigaction() for origin of this code. 1919 */ 1920 SIGDELSET(p->p_sigcatch, sig); 1921 if (sig != SIGCONT && 1922 sigprop(sig) & SA_IGNORE) 1923 SIGADDSET(p->p_sigignore, sig); 1924 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1925 } 1926 1927 /* 1928 * Handle the mailbox case. Copyout to the appropriate 1929 * location but do not generate a signal frame. The system 1930 * call simply returns EINTR and the user is responsible for 1931 * polling the mailbox. 1932 */ 1933 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1934 int sig_copy = sig; 1935 copyout(&sig_copy, (void *)action, sizeof(int)); 1936 curproc->p_flag |= P_MAILBOX; 1937 crit_exit(); 1938 goto done; 1939 } 1940 1941 /* 1942 * Set the signal mask and calculate the mask to restore 1943 * when the signal function returns. 1944 * 1945 * Special case: user has done a sigsuspend. Here the 1946 * current mask is not of interest, but rather the 1947 * mask from before the sigsuspend is what we want 1948 * restored after the signal processing is completed. 1949 */ 1950 if (lp->lwp_flag & LWP_OLDMASK) { 1951 returnmask = lp->lwp_oldsigmask; 1952 lp->lwp_flag &= ~LWP_OLDMASK; 1953 } else { 1954 returnmask = lp->lwp_sigmask; 1955 } 1956 1957 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1958 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1959 SIGADDSET(lp->lwp_sigmask, sig); 1960 1961 crit_exit(); 1962 lp->lwp_ru.ru_nsignals++; 1963 if (lp->lwp_sig != sig) { 1964 code = 0; 1965 } else { 1966 code = lp->lwp_code; 1967 lp->lwp_code = 0; 1968 lp->lwp_sig = 0; 1969 } 1970 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1971 } 1972 done: 1973 ; 1974 } 1975 1976 /* 1977 * Kill the current process for stated reason. 1978 */ 1979 void 1980 killproc(struct proc *p, char *why) 1981 { 1982 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1983 p->p_pid, p->p_comm, 1984 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1985 ksignal(p, SIGKILL); 1986 } 1987 1988 /* 1989 * Force the current process to exit with the specified signal, dumping core 1990 * if appropriate. We bypass the normal tests for masked and caught signals, 1991 * allowing unrecoverable failures to terminate the process without changing 1992 * signal state. Mark the accounting record with the signal termination. 1993 * If dumping core, save the signal number for the debugger. Calls exit and 1994 * does not return. 1995 * 1996 * This routine does not return. 1997 */ 1998 void 1999 sigexit(struct lwp *lp, int sig) 2000 { 2001 struct proc *p = lp->lwp_proc; 2002 2003 p->p_acflag |= AXSIG; 2004 if (sigprop(sig) & SA_CORE) { 2005 lp->lwp_sig = sig; 2006 /* 2007 * Log signals which would cause core dumps 2008 * (Log as LOG_INFO to appease those who don't want 2009 * these messages.) 2010 * XXX : Todo, as well as euid, write out ruid too 2011 */ 2012 if (coredump(lp, sig) == 0) 2013 sig |= WCOREFLAG; 2014 if (kern_logsigexit) 2015 log(LOG_INFO, 2016 "pid %d (%s), uid %d: exited on signal %d%s\n", 2017 p->p_pid, p->p_comm, 2018 p->p_ucred ? p->p_ucred->cr_uid : -1, 2019 sig &~ WCOREFLAG, 2020 sig & WCOREFLAG ? " (core dumped)" : ""); 2021 } 2022 exit1(W_EXITCODE(0, sig)); 2023 /* NOTREACHED */ 2024 } 2025 2026 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2027 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2028 sizeof(corefilename), "process corefile name format string"); 2029 2030 /* 2031 * expand_name(name, uid, pid) 2032 * Expand the name described in corefilename, using name, uid, and pid. 2033 * corefilename is a kprintf-like string, with three format specifiers: 2034 * %N name of process ("name") 2035 * %P process id (pid) 2036 * %U user id (uid) 2037 * For example, "%N.core" is the default; they can be disabled completely 2038 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2039 * This is controlled by the sysctl variable kern.corefile (see above). 2040 */ 2041 2042 static char * 2043 expand_name(const char *name, uid_t uid, pid_t pid) 2044 { 2045 char *temp; 2046 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2047 int i, n; 2048 char *format = corefilename; 2049 size_t namelen; 2050 2051 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2052 if (temp == NULL) 2053 return NULL; 2054 namelen = strlen(name); 2055 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2056 int l; 2057 switch (format[i]) { 2058 case '%': /* Format character */ 2059 i++; 2060 switch (format[i]) { 2061 case '%': 2062 temp[n++] = '%'; 2063 break; 2064 case 'N': /* process name */ 2065 if ((n + namelen) > MAXPATHLEN) { 2066 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2067 pid, name, uid, temp, name); 2068 kfree(temp, M_TEMP); 2069 return NULL; 2070 } 2071 memcpy(temp+n, name, namelen); 2072 n += namelen; 2073 break; 2074 case 'P': /* process id */ 2075 l = ksprintf(buf, "%u", pid); 2076 if ((n + l) > MAXPATHLEN) { 2077 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2078 pid, name, uid, temp, name); 2079 kfree(temp, M_TEMP); 2080 return NULL; 2081 } 2082 memcpy(temp+n, buf, l); 2083 n += l; 2084 break; 2085 case 'U': /* user id */ 2086 l = ksprintf(buf, "%u", uid); 2087 if ((n + l) > MAXPATHLEN) { 2088 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2089 pid, name, uid, temp, name); 2090 kfree(temp, M_TEMP); 2091 return NULL; 2092 } 2093 memcpy(temp+n, buf, l); 2094 n += l; 2095 break; 2096 default: 2097 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2098 } 2099 break; 2100 default: 2101 temp[n++] = format[i]; 2102 } 2103 } 2104 temp[n] = '\0'; 2105 return temp; 2106 } 2107 2108 /* 2109 * Dump a process' core. The main routine does some 2110 * policy checking, and creates the name of the coredump; 2111 * then it passes on a vnode and a size limit to the process-specific 2112 * coredump routine if there is one; if there _is not_ one, it returns 2113 * ENOSYS; otherwise it returns the error from the process-specific routine. 2114 * 2115 * The parameter `lp' is the lwp which triggered the coredump. 2116 */ 2117 2118 static int 2119 coredump(struct lwp *lp, int sig) 2120 { 2121 struct proc *p = lp->lwp_proc; 2122 struct vnode *vp; 2123 struct ucred *cred = p->p_ucred; 2124 struct flock lf; 2125 struct nlookupdata nd; 2126 struct vattr vattr; 2127 int error, error1; 2128 char *name; /* name of corefile */ 2129 off_t limit; 2130 2131 STOPEVENT(p, S_CORE, 0); 2132 2133 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2134 return (EFAULT); 2135 2136 /* 2137 * Note that the bulk of limit checking is done after 2138 * the corefile is created. The exception is if the limit 2139 * for corefiles is 0, in which case we don't bother 2140 * creating the corefile at all. This layout means that 2141 * a corefile is truncated instead of not being created, 2142 * if it is larger than the limit. 2143 */ 2144 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2145 if (limit == 0) 2146 return EFBIG; 2147 2148 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2149 if (name == NULL) 2150 return (EINVAL); 2151 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2152 if (error == 0) 2153 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2154 kfree(name, M_TEMP); 2155 if (error) { 2156 nlookup_done(&nd); 2157 return (error); 2158 } 2159 vp = nd.nl_open_vp; 2160 nd.nl_open_vp = NULL; 2161 nlookup_done(&nd); 2162 2163 vn_unlock(vp); 2164 lf.l_whence = SEEK_SET; 2165 lf.l_start = 0; 2166 lf.l_len = 0; 2167 lf.l_type = F_WRLCK; 2168 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2169 if (error) 2170 goto out2; 2171 2172 /* Don't dump to non-regular files or files with links. */ 2173 if (vp->v_type != VREG || 2174 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2175 error = EFAULT; 2176 goto out1; 2177 } 2178 2179 /* Don't dump to files current user does not own */ 2180 if (vattr.va_uid != p->p_ucred->cr_uid) { 2181 error = EFAULT; 2182 goto out1; 2183 } 2184 2185 VATTR_NULL(&vattr); 2186 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2187 vattr.va_size = 0; 2188 VOP_SETATTR(vp, &vattr, cred); 2189 p->p_acflag |= ACORE; 2190 vn_unlock(vp); 2191 2192 error = p->p_sysent->sv_coredump ? 2193 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2194 2195 out1: 2196 lf.l_type = F_UNLCK; 2197 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2198 out2: 2199 error1 = vn_close(vp, FWRITE); 2200 if (error == 0) 2201 error = error1; 2202 return (error); 2203 } 2204 2205 /* 2206 * Nonexistent system call-- signal process (may want to handle it). 2207 * Flag error in case process won't see signal immediately (blocked or ignored). 2208 * 2209 * MPALMOSTSAFE 2210 */ 2211 /* ARGSUSED */ 2212 int 2213 sys_nosys(struct nosys_args *args) 2214 { 2215 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2216 return (EINVAL); 2217 } 2218 2219 /* 2220 * Send a SIGIO or SIGURG signal to a process or process group using 2221 * stored credentials rather than those of the current process. 2222 */ 2223 void 2224 pgsigio(struct sigio *sigio, int sig, int checkctty) 2225 { 2226 if (sigio == NULL) 2227 return; 2228 2229 if (sigio->sio_pgid > 0) { 2230 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2231 sigio->sio_proc)) 2232 ksignal(sigio->sio_proc, sig); 2233 } else if (sigio->sio_pgid < 0) { 2234 struct proc *p; 2235 2236 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2237 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2238 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2239 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2240 ksignal(p, sig); 2241 } 2242 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2243 } 2244 } 2245 2246 static int 2247 filt_sigattach(struct knote *kn) 2248 { 2249 struct proc *p = curproc; 2250 2251 kn->kn_ptr.p_proc = p; 2252 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2253 2254 /* XXX lock the proc here while adding to the list? */ 2255 knote_insert(&p->p_klist, kn); 2256 2257 return (0); 2258 } 2259 2260 static void 2261 filt_sigdetach(struct knote *kn) 2262 { 2263 struct proc *p = kn->kn_ptr.p_proc; 2264 2265 knote_remove(&p->p_klist, kn); 2266 } 2267 2268 /* 2269 * signal knotes are shared with proc knotes, so we apply a mask to 2270 * the hint in order to differentiate them from process hints. This 2271 * could be avoided by using a signal-specific knote list, but probably 2272 * isn't worth the trouble. 2273 */ 2274 static int 2275 filt_signal(struct knote *kn, long hint) 2276 { 2277 if (hint & NOTE_SIGNAL) { 2278 hint &= ~NOTE_SIGNAL; 2279 2280 if (kn->kn_id == hint) 2281 kn->kn_data++; 2282 } 2283 return (kn->kn_data != 0); 2284 } 2285