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(&p->p_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(&p->p_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 lwkt_reltoken(&p->p_token); 280 return (EINVAL); 281 } 282 #endif 283 } 284 285 /* 286 * Change setting atomically. 287 */ 288 crit_enter(); 289 290 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 291 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 292 if (act->sa_flags & SA_SIGINFO) { 293 ps->ps_sigact[_SIG_IDX(sig)] = 294 (__sighandler_t *)act->sa_sigaction; 295 SIGADDSET(ps->ps_siginfo, sig); 296 } else { 297 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 298 SIGDELSET(ps->ps_siginfo, sig); 299 } 300 if (!(act->sa_flags & SA_RESTART)) 301 SIGADDSET(ps->ps_sigintr, sig); 302 else 303 SIGDELSET(ps->ps_sigintr, sig); 304 if (act->sa_flags & SA_ONSTACK) 305 SIGADDSET(ps->ps_sigonstack, sig); 306 else 307 SIGDELSET(ps->ps_sigonstack, sig); 308 if (act->sa_flags & SA_RESETHAND) 309 SIGADDSET(ps->ps_sigreset, sig); 310 else 311 SIGDELSET(ps->ps_sigreset, sig); 312 if (act->sa_flags & SA_NODEFER) 313 SIGADDSET(ps->ps_signodefer, sig); 314 else 315 SIGDELSET(ps->ps_signodefer, sig); 316 if (act->sa_flags & SA_MAILBOX) 317 SIGADDSET(ps->ps_sigmailbox, sig); 318 else 319 SIGDELSET(ps->ps_sigmailbox, sig); 320 if (sig == SIGCHLD) { 321 if (act->sa_flags & SA_NOCLDSTOP) 322 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 323 else 324 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 325 if (act->sa_flags & SA_NOCLDWAIT) { 326 /* 327 * Paranoia: since SA_NOCLDWAIT is implemented 328 * by reparenting the dying child to PID 1 (and 329 * trust it to reap the zombie), PID 1 itself 330 * is forbidden to set SA_NOCLDWAIT. 331 */ 332 if (p->p_pid == 1) 333 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 334 else 335 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 336 } else { 337 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 338 } 339 } 340 /* 341 * Set bit in p_sigignore for signals that are set to SIG_IGN, 342 * and for signals set to SIG_DFL where the default is to 343 * ignore. However, don't put SIGCONT in p_sigignore, as we 344 * have to restart the process. 345 */ 346 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 347 (sigprop(sig) & SA_IGNORE && 348 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 349 /* never to be seen again */ 350 SIGDELSET(p->p_siglist, sig); 351 /* 352 * Remove the signal also from the thread lists. 353 */ 354 FOREACH_LWP_IN_PROC(lp, p) { 355 SIGDELSET(lp->lwp_siglist, sig); 356 } 357 if (sig != SIGCONT) { 358 /* easier in ksignal */ 359 SIGADDSET(p->p_sigignore, sig); 360 } 361 SIGDELSET(p->p_sigcatch, sig); 362 } else { 363 SIGDELSET(p->p_sigignore, sig); 364 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 365 SIGDELSET(p->p_sigcatch, sig); 366 else 367 SIGADDSET(p->p_sigcatch, sig); 368 } 369 370 crit_exit(); 371 } 372 lwkt_reltoken(&p->p_token); 373 return (0); 374 } 375 376 int 377 sys_sigaction(struct sigaction_args *uap) 378 { 379 struct sigaction act, oact; 380 struct sigaction *actp, *oactp; 381 int error; 382 383 actp = (uap->act != NULL) ? &act : NULL; 384 oactp = (uap->oact != NULL) ? &oact : NULL; 385 if (actp) { 386 error = copyin(uap->act, actp, sizeof(act)); 387 if (error) 388 return (error); 389 } 390 error = kern_sigaction(uap->sig, actp, oactp); 391 if (oactp && !error) { 392 error = copyout(oactp, uap->oact, sizeof(oact)); 393 } 394 return (error); 395 } 396 397 /* 398 * Initialize signal state for process 0; 399 * set to ignore signals that are ignored by default. 400 */ 401 void 402 siginit(struct proc *p) 403 { 404 int i; 405 406 for (i = 1; i <= NSIG; i++) 407 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 408 SIGADDSET(p->p_sigignore, i); 409 } 410 411 /* 412 * Reset signals for an exec of the specified process. 413 */ 414 void 415 execsigs(struct proc *p) 416 { 417 struct sigacts *ps = p->p_sigacts; 418 struct lwp *lp; 419 int sig; 420 421 lp = ONLY_LWP_IN_PROC(p); 422 423 /* 424 * Reset caught signals. Held signals remain held 425 * through p_sigmask (unless they were caught, 426 * and are now ignored by default). 427 */ 428 while (SIGNOTEMPTY(p->p_sigcatch)) { 429 sig = sig_ffs(&p->p_sigcatch); 430 SIGDELSET(p->p_sigcatch, sig); 431 if (sigprop(sig) & SA_IGNORE) { 432 if (sig != SIGCONT) 433 SIGADDSET(p->p_sigignore, sig); 434 SIGDELSET(p->p_siglist, sig); 435 SIGDELSET(lp->lwp_siglist, sig); 436 } 437 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 438 } 439 440 /* 441 * Reset stack state to the user stack. 442 * Clear set of signals caught on the signal stack. 443 */ 444 lp->lwp_sigstk.ss_flags = SS_DISABLE; 445 lp->lwp_sigstk.ss_size = 0; 446 lp->lwp_sigstk.ss_sp = 0; 447 lp->lwp_flag &= ~LWP_ALTSTACK; 448 /* 449 * Reset no zombies if child dies flag as Solaris does. 450 */ 451 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 452 } 453 454 /* 455 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 456 * 457 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 458 * p == curproc. 459 */ 460 int 461 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 462 { 463 struct thread *td = curthread; 464 struct lwp *lp = td->td_lwp; 465 struct proc *p = td->td_proc; 466 int error; 467 468 lwkt_gettoken(&p->p_token); 469 470 if (oset != NULL) 471 *oset = lp->lwp_sigmask; 472 473 error = 0; 474 if (set != NULL) { 475 switch (how) { 476 case SIG_BLOCK: 477 SIG_CANTMASK(*set); 478 SIGSETOR(lp->lwp_sigmask, *set); 479 break; 480 case SIG_UNBLOCK: 481 SIGSETNAND(lp->lwp_sigmask, *set); 482 break; 483 case SIG_SETMASK: 484 SIG_CANTMASK(*set); 485 lp->lwp_sigmask = *set; 486 break; 487 default: 488 error = EINVAL; 489 break; 490 } 491 } 492 493 lwkt_reltoken(&p->p_token); 494 495 return (error); 496 } 497 498 /* 499 * sigprocmask() 500 * 501 * MPSAFE 502 */ 503 int 504 sys_sigprocmask(struct sigprocmask_args *uap) 505 { 506 sigset_t set, oset; 507 sigset_t *setp, *osetp; 508 int error; 509 510 setp = (uap->set != NULL) ? &set : NULL; 511 osetp = (uap->oset != NULL) ? &oset : NULL; 512 if (setp) { 513 error = copyin(uap->set, setp, sizeof(set)); 514 if (error) 515 return (error); 516 } 517 error = kern_sigprocmask(uap->how, setp, osetp); 518 if (osetp && !error) { 519 error = copyout(osetp, uap->oset, sizeof(oset)); 520 } 521 return (error); 522 } 523 524 /* 525 * MPSAFE 526 */ 527 int 528 kern_sigpending(struct __sigset *set) 529 { 530 struct lwp *lp = curthread->td_lwp; 531 532 *set = lwp_sigpend(lp); 533 534 return (0); 535 } 536 537 /* 538 * MPSAFE 539 */ 540 int 541 sys_sigpending(struct sigpending_args *uap) 542 { 543 sigset_t set; 544 int error; 545 546 error = kern_sigpending(&set); 547 548 if (error == 0) 549 error = copyout(&set, uap->set, sizeof(set)); 550 return (error); 551 } 552 553 /* 554 * Suspend process until signal, providing mask to be set 555 * in the meantime. 556 * 557 * MPSAFE 558 */ 559 int 560 kern_sigsuspend(struct __sigset *set) 561 { 562 struct thread *td = curthread; 563 struct lwp *lp = td->td_lwp; 564 struct proc *p = td->td_proc; 565 struct sigacts *ps = p->p_sigacts; 566 567 /* 568 * When returning from sigsuspend, we want 569 * the old mask to be restored after the 570 * signal handler has finished. Thus, we 571 * save it here and mark the sigacts structure 572 * to indicate this. 573 */ 574 lp->lwp_oldsigmask = lp->lwp_sigmask; 575 lp->lwp_flag |= LWP_OLDMASK; 576 577 SIG_CANTMASK(*set); 578 lp->lwp_sigmask = *set; 579 while (tsleep(ps, PCATCH, "pause", 0) == 0) 580 /* void */; 581 /* always return EINTR rather than ERESTART... */ 582 return (EINTR); 583 } 584 585 /* 586 * Note nonstandard calling convention: libc stub passes mask, not 587 * pointer, to save a copyin. 588 * 589 * MPSAFE 590 */ 591 int 592 sys_sigsuspend(struct sigsuspend_args *uap) 593 { 594 sigset_t mask; 595 int error; 596 597 error = copyin(uap->sigmask, &mask, sizeof(mask)); 598 if (error) 599 return (error); 600 601 error = kern_sigsuspend(&mask); 602 603 return (error); 604 } 605 606 /* 607 * MPSAFE 608 */ 609 int 610 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 611 { 612 struct thread *td = curthread; 613 struct lwp *lp = td->td_lwp; 614 struct proc *p = td->td_proc; 615 616 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 617 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 618 619 if (oss) 620 *oss = lp->lwp_sigstk; 621 622 if (ss) { 623 if (ss->ss_flags & SS_DISABLE) { 624 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 625 return (EINVAL); 626 lp->lwp_flag &= ~LWP_ALTSTACK; 627 lp->lwp_sigstk.ss_flags = ss->ss_flags; 628 } else { 629 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 630 return (ENOMEM); 631 lp->lwp_flag |= LWP_ALTSTACK; 632 lp->lwp_sigstk = *ss; 633 } 634 } 635 636 return (0); 637 } 638 639 /* 640 * MPSAFE 641 */ 642 int 643 sys_sigaltstack(struct sigaltstack_args *uap) 644 { 645 stack_t ss, oss; 646 int error; 647 648 if (uap->ss) { 649 error = copyin(uap->ss, &ss, sizeof(ss)); 650 if (error) 651 return (error); 652 } 653 654 error = kern_sigaltstack(uap->ss ? &ss : NULL, 655 uap->oss ? &oss : NULL); 656 657 if (error == 0 && uap->oss) 658 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 659 return (error); 660 } 661 662 /* 663 * Common code for kill process group/broadcast kill. 664 * cp is calling process. 665 */ 666 struct killpg_info { 667 int nfound; 668 int sig; 669 }; 670 671 static int killpg_all_callback(struct proc *p, void *data); 672 673 static int 674 dokillpg(int sig, int pgid, int all) 675 { 676 struct killpg_info info; 677 struct proc *cp = curproc; 678 struct proc *p; 679 struct pgrp *pgrp; 680 681 info.nfound = 0; 682 info.sig = sig; 683 684 if (all) { 685 /* 686 * broadcast 687 */ 688 allproc_scan(killpg_all_callback, &info); 689 } else { 690 if (pgid == 0) { 691 /* 692 * zero pgid means send to my process group. 693 */ 694 pgrp = cp->p_pgrp; 695 } else { 696 pgrp = pgfind(pgid); 697 if (pgrp == NULL) 698 return (ESRCH); 699 } 700 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 701 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 702 if (p->p_pid <= 1 || 703 p->p_stat == SZOMB || 704 (p->p_flag & P_SYSTEM) || 705 !CANSIGNAL(p, sig)) { 706 continue; 707 } 708 ++info.nfound; 709 if (sig) 710 ksignal(p, sig); 711 } 712 lockmgr(&pgrp->pg_lock, LK_RELEASE); 713 } 714 return (info.nfound ? 0 : ESRCH); 715 } 716 717 static int 718 killpg_all_callback(struct proc *p, void *data) 719 { 720 struct killpg_info *info = data; 721 722 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 723 p == curproc || !CANSIGNAL(p, info->sig)) { 724 return (0); 725 } 726 ++info->nfound; 727 if (info->sig) 728 ksignal(p, info->sig); 729 return(0); 730 } 731 732 /* 733 * Send a general signal to a process or LWPs within that process. Note 734 * that new signals cannot be sent if a process is exiting. 735 * 736 * No requirements. 737 */ 738 int 739 kern_kill(int sig, pid_t pid, lwpid_t tid) 740 { 741 int t; 742 743 if ((u_int)sig > _SIG_MAXSIG) 744 return (EINVAL); 745 746 lwkt_gettoken(&proc_token); 747 748 if (pid > 0) { 749 struct proc *p; 750 struct lwp *lp = NULL; 751 752 /* kill single process */ 753 if ((p = pfind(pid)) == NULL) { 754 lwkt_reltoken(&proc_token); 755 return (ESRCH); 756 } 757 PHOLD(p); 758 lwkt_gettoken(&p->p_token); 759 if (!CANSIGNAL(p, sig)) { 760 lwkt_reltoken(&p->p_token); 761 PRELE(p); 762 lwkt_reltoken(&proc_token); 763 return (EPERM); 764 } 765 766 /* 767 * NOP if the process is exiting. Note that lwpsignal() is 768 * called directly with P_WEXIT set to kill individual LWPs 769 * during exit, which is allowed. 770 */ 771 if (p->p_flag & P_WEXIT) { 772 lwkt_reltoken(&p->p_token); 773 PRELE(p); 774 lwkt_reltoken(&proc_token); 775 return (0); 776 } 777 if (tid != -1) { 778 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 779 if (lp == NULL) { 780 lwkt_reltoken(&p->p_token); 781 PRELE(p); 782 lwkt_reltoken(&proc_token); 783 return (ESRCH); 784 } 785 } 786 if (sig) 787 lwpsignal(p, lp, sig); 788 lwkt_reltoken(&p->p_token); 789 PRELE(p); 790 lwkt_reltoken(&proc_token); 791 return (0); 792 } 793 794 /* 795 * If we come here, pid is a special broadcast pid. 796 * This doesn't mix with a tid. 797 */ 798 if (tid != -1) { 799 lwkt_reltoken(&proc_token); 800 return (EINVAL); 801 } 802 switch (pid) { 803 case -1: /* broadcast signal */ 804 t = (dokillpg(sig, 0, 1)); 805 break; 806 case 0: /* signal own process group */ 807 t = (dokillpg(sig, 0, 0)); 808 break; 809 default: /* negative explicit process group */ 810 t = (dokillpg(sig, -pid, 0)); 811 break; 812 } 813 lwkt_reltoken(&proc_token); 814 return t; 815 } 816 817 int 818 sys_kill(struct kill_args *uap) 819 { 820 int error; 821 822 error = kern_kill(uap->signum, uap->pid, -1); 823 return (error); 824 } 825 826 int 827 sys_lwp_kill(struct lwp_kill_args *uap) 828 { 829 int error; 830 pid_t pid = uap->pid; 831 832 /* 833 * A tid is mandatory for lwp_kill(), otherwise 834 * you could simply use kill(). 835 */ 836 if (uap->tid == -1) 837 return (EINVAL); 838 839 /* 840 * To save on a getpid() function call for intra-process 841 * signals, pid == -1 means current process. 842 */ 843 if (pid == -1) 844 pid = curproc->p_pid; 845 846 error = kern_kill(uap->signum, pid, uap->tid); 847 return (error); 848 } 849 850 /* 851 * Send a signal to a process group. 852 */ 853 void 854 gsignal(int pgid, int sig) 855 { 856 struct pgrp *pgrp; 857 858 if (pgid && (pgrp = pgfind(pgid))) 859 pgsignal(pgrp, sig, 0); 860 } 861 862 /* 863 * Send a signal to a process group. If checktty is 1, 864 * limit to members which have a controlling terminal. 865 * 866 * pg_lock interlocks against a fork that might be in progress, to 867 * ensure that the new child process picks up the signal. 868 */ 869 void 870 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 871 { 872 struct proc *p; 873 874 if (pgrp) { 875 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 876 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 877 if (checkctty == 0 || p->p_flag & P_CONTROLT) 878 ksignal(p, sig); 879 } 880 lockmgr(&pgrp->pg_lock, LK_RELEASE); 881 } 882 } 883 884 /* 885 * Send a signal caused by a trap to the current lwp. If it will be caught 886 * immediately, deliver it with correct code. Otherwise, post it normally. 887 * 888 * These signals may ONLY be delivered to the specified lwp and may never 889 * be delivered to the process generically. 890 */ 891 void 892 trapsignal(struct lwp *lp, int sig, u_long code) 893 { 894 struct proc *p = lp->lwp_proc; 895 struct sigacts *ps = p->p_sigacts; 896 897 /* 898 * If we are a virtual kernel running an emulated user process 899 * context, switch back to the virtual kernel context before 900 * trying to post the signal. 901 */ 902 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 903 struct trapframe *tf = lp->lwp_md.md_regs; 904 tf->tf_trapno = 0; 905 vkernel_trap(lp, tf); 906 } 907 908 909 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 910 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 911 lp->lwp_ru.ru_nsignals++; 912 #ifdef KTRACE 913 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 914 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 915 &lp->lwp_sigmask, code); 916 #endif 917 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 918 &lp->lwp_sigmask, code); 919 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 920 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 921 SIGADDSET(lp->lwp_sigmask, sig); 922 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 923 /* 924 * See kern_sigaction() for origin of this code. 925 */ 926 SIGDELSET(p->p_sigcatch, sig); 927 if (sig != SIGCONT && 928 sigprop(sig) & SA_IGNORE) 929 SIGADDSET(p->p_sigignore, sig); 930 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 931 } 932 } else { 933 lp->lwp_code = code; /* XXX for core dump/debugger */ 934 lp->lwp_sig = sig; /* XXX to verify code */ 935 lwpsignal(p, lp, sig); 936 } 937 } 938 939 /* 940 * Find a suitable lwp to deliver the signal to. 941 * 942 * Returns NULL if all lwps hold the signal blocked. 943 */ 944 static struct lwp * 945 find_lwp_for_signal(struct proc *p, int sig) 946 { 947 struct lwp *lp; 948 struct lwp *run, *sleep, *stop; 949 950 /* 951 * If the running/preempted thread belongs to the proc to which 952 * the signal is being delivered and this thread does not block 953 * the signal, then we can avoid a context switch by delivering 954 * the signal to this thread, because it will return to userland 955 * soon anyways. 956 */ 957 lp = lwkt_preempted_proc(); 958 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig)) 959 return (lp); 960 961 run = sleep = stop = NULL; 962 FOREACH_LWP_IN_PROC(lp, p) { 963 /* 964 * If the signal is being blocked by the lwp, then this 965 * lwp is not eligible for receiving the signal. 966 */ 967 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 968 continue; 969 970 switch (lp->lwp_stat) { 971 case LSRUN: 972 run = lp; 973 break; 974 975 case LSSTOP: 976 stop = lp; 977 break; 978 979 case LSSLEEP: 980 if (lp->lwp_flag & LWP_SINTR) 981 sleep = lp; 982 break; 983 } 984 } 985 986 if (run != NULL) 987 return (run); 988 else if (sleep != NULL) 989 return (sleep); 990 else 991 return (stop); 992 } 993 994 /* 995 * Send the signal to the process. If the signal has an action, the action 996 * is usually performed by the target process rather than the caller; we add 997 * the signal to the set of pending signals for the process. 998 * 999 * Exceptions: 1000 * o When a stop signal is sent to a sleeping process that takes the 1001 * default action, the process is stopped without awakening it. 1002 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1003 * regardless of the signal action (eg, blocked or ignored). 1004 * 1005 * Other ignored signals are discarded immediately. 1006 * 1007 * No requirements. 1008 */ 1009 void 1010 ksignal(struct proc *p, int sig) 1011 { 1012 lwpsignal(p, NULL, sig); 1013 } 1014 1015 /* 1016 * The core for ksignal. lp may be NULL, then a suitable thread 1017 * will be chosen. If not, lp MUST be a member of p. 1018 * 1019 * No requirements. 1020 */ 1021 void 1022 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1023 { 1024 int prop; 1025 sig_t action; 1026 1027 if (sig > _SIG_MAXSIG || sig <= 0) { 1028 kprintf("lwpsignal: signal %d\n", sig); 1029 panic("lwpsignal signal number"); 1030 } 1031 1032 KKASSERT(lp == NULL || lp->lwp_proc == p); 1033 1034 lwkt_gettoken(&p->p_token); 1035 1036 prop = sigprop(sig); 1037 1038 /* 1039 * If proc is traced, always give parent a chance; 1040 * if signal event is tracked by procfs, give *that* 1041 * a chance, as well. 1042 */ 1043 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1044 action = SIG_DFL; 1045 } else { 1046 /* 1047 * Do not try to deliver signals to an exiting lwp. Note 1048 * that we must still deliver the signal if P_WEXIT is set 1049 * in the process flags. 1050 */ 1051 if (lp && (lp->lwp_flag & LWP_WEXIT)) { 1052 lwkt_reltoken(&p->p_token); 1053 return; 1054 } 1055 1056 /* 1057 * If the signal is being ignored, then we forget about 1058 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1059 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1060 */ 1061 if (SIGISMEMBER(p->p_sigignore, sig)) { 1062 lwkt_reltoken(&p->p_token); 1063 return; 1064 } 1065 if (SIGISMEMBER(p->p_sigcatch, sig)) 1066 action = SIG_CATCH; 1067 else 1068 action = SIG_DFL; 1069 } 1070 1071 /* 1072 * If continuing, clear any pending STOP signals. 1073 */ 1074 if (prop & SA_CONT) 1075 SIG_STOPSIGMASK(p->p_siglist); 1076 1077 if (prop & SA_STOP) { 1078 /* 1079 * If sending a tty stop signal to a member of an orphaned 1080 * process group, discard the signal here if the action 1081 * is default; don't stop the process below if sleeping, 1082 * and don't clear any pending SIGCONT. 1083 */ 1084 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1085 action == SIG_DFL) { 1086 lwkt_reltoken(&p->p_token); 1087 return; 1088 } 1089 SIG_CONTSIGMASK(p->p_siglist); 1090 p->p_flag &= ~P_CONTINUED; 1091 } 1092 1093 crit_enter(); 1094 1095 if (p->p_stat == SSTOP) { 1096 /* 1097 * Nobody can handle this signal, add it to the lwp or 1098 * process pending list 1099 */ 1100 if (lp) 1101 SIGADDSET(lp->lwp_siglist, sig); 1102 else 1103 SIGADDSET(p->p_siglist, sig); 1104 1105 /* 1106 * If the process is stopped and is being traced, then no 1107 * further action is necessary. 1108 */ 1109 if (p->p_flag & P_TRACED) 1110 goto out; 1111 1112 /* 1113 * If the process is stopped and receives a KILL signal, 1114 * make the process runnable. 1115 */ 1116 if (sig == SIGKILL) { 1117 proc_unstop(p); 1118 goto active_process; 1119 } 1120 1121 /* 1122 * If the process is stopped and receives a CONT signal, 1123 * then try to make the process runnable again. 1124 */ 1125 if (prop & SA_CONT) { 1126 /* 1127 * If SIGCONT is default (or ignored), we continue the 1128 * process but don't leave the signal in p_siglist, as 1129 * it has no further action. If SIGCONT is held, we 1130 * continue the process and leave the signal in 1131 * p_siglist. If the process catches SIGCONT, let it 1132 * handle the signal itself. 1133 */ 1134 /* XXX what if the signal is being held blocked? */ 1135 p->p_flag |= P_CONTINUED; 1136 wakeup(p->p_pptr); 1137 if (action == SIG_DFL) 1138 SIGDELSET(p->p_siglist, sig); 1139 proc_unstop(p); 1140 if (action == SIG_CATCH) 1141 goto active_process; 1142 goto out; 1143 } 1144 1145 /* 1146 * If the process is stopped and receives another STOP 1147 * signal, we do not need to stop it again. If we did 1148 * the shell could get confused. 1149 * 1150 * However, if the current/preempted lwp is part of the 1151 * process receiving the signal, we need to keep it, 1152 * so that this lwp can stop in issignal() later, as 1153 * we don't want to wait until it reaches userret! 1154 */ 1155 if (prop & SA_STOP) { 1156 if (lwkt_preempted_proc() == NULL || 1157 lwkt_preempted_proc()->lwp_proc != p) 1158 SIGDELSET(p->p_siglist, sig); 1159 } 1160 1161 /* 1162 * Otherwise the process is stopped and it received some 1163 * signal, which does not change its stopped state. 1164 * 1165 * We have to select one thread to set LWP_BREAKTSLEEP, 1166 * so that the current signal will break the sleep 1167 * as soon as a SA_CONT signal will unstop the process. 1168 */ 1169 if (lp == NULL) 1170 lp = find_lwp_for_signal(p, sig); 1171 if (lp != NULL && 1172 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1173 lp->lwp_flag |= LWP_BREAKTSLEEP; 1174 goto out; 1175 1176 /* NOTREACHED */ 1177 } 1178 /* else not stopped */ 1179 active_process: 1180 1181 /* 1182 * Never deliver a lwp-specific signal to a random lwp. 1183 */ 1184 if (lp == NULL) { 1185 lp = find_lwp_for_signal(p, sig); 1186 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1187 lp = NULL; 1188 } 1189 1190 /* 1191 * Deliver to the process generically if (1) the signal is being 1192 * sent to any thread or (2) we could not find a thread to deliver 1193 * it to. 1194 */ 1195 if (lp == NULL) { 1196 SIGADDSET(p->p_siglist, sig); 1197 goto out; 1198 } 1199 1200 /* 1201 * Deliver to a specific LWP whether it masks it or not. It will 1202 * not be dispatched if masked but we must still deliver it. 1203 */ 1204 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1205 (p->p_flag & P_TRACED) == 0) { 1206 p->p_nice = NZERO; 1207 } 1208 1209 /* 1210 * If the process receives a STOP signal which indeed needs to 1211 * stop the process, do so. If the process chose to catch the 1212 * signal, it will be treated like any other signal. 1213 */ 1214 if ((prop & SA_STOP) && action == SIG_DFL) { 1215 /* 1216 * If a child holding parent blocked, stopping 1217 * could cause deadlock. Take no action at this 1218 * time. 1219 */ 1220 if (p->p_flag & P_PPWAIT) { 1221 SIGADDSET(p->p_siglist, sig); 1222 goto out; 1223 } 1224 1225 /* 1226 * Do not actually try to manipulate the process, but simply 1227 * stop it. Lwps will stop as soon as they safely can. 1228 */ 1229 p->p_xstat = sig; 1230 proc_stop(p); 1231 goto out; 1232 } 1233 1234 /* 1235 * If it is a CONT signal with default action, just ignore it. 1236 */ 1237 if ((prop & SA_CONT) && action == SIG_DFL) 1238 goto out; 1239 1240 /* 1241 * Mark signal pending at this specific thread. 1242 */ 1243 SIGADDSET(lp->lwp_siglist, sig); 1244 1245 lwp_signotify(lp); 1246 1247 out: 1248 lwkt_reltoken(&p->p_token); 1249 crit_exit(); 1250 } 1251 1252 /* 1253 * p->p_token must be held 1254 */ 1255 static void 1256 lwp_signotify(struct lwp *lp) 1257 { 1258 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1259 crit_enter(); 1260 1261 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1262 /* 1263 * Thread is in tsleep. 1264 */ 1265 1266 /* 1267 * If the thread is sleeping uninterruptibly 1268 * we can't interrupt the sleep... the signal will 1269 * be noticed when the lwp returns through 1270 * trap() or syscall(). 1271 * 1272 * Otherwise the signal can interrupt the sleep. 1273 * 1274 * If the process is traced, the lwp will handle the 1275 * tracing in issignal() when it returns to userland. 1276 */ 1277 if (lp->lwp_flag & LWP_SINTR) { 1278 /* 1279 * Make runnable and break out of any tsleep as well. 1280 */ 1281 lp->lwp_flag |= LWP_BREAKTSLEEP; 1282 setrunnable(lp); 1283 } 1284 } else { 1285 /* 1286 * Otherwise the thread is running 1287 * 1288 * LSRUN does nothing with the signal, other than kicking 1289 * ourselves if we are running. 1290 * SZOMB and SIDL mean that it will either never be noticed, 1291 * or noticed very soon. 1292 * 1293 * Note that lwp_thread may be NULL or may not be completely 1294 * initialized if the process is in the SIDL or SZOMB state. 1295 * 1296 * For SMP we may have to forward the request to another cpu. 1297 * YYY the MP lock prevents the target process from moving 1298 * to another cpu, see kern/kern_switch.c 1299 * 1300 * If the target thread is waiting on its message port, 1301 * wakeup the target thread so it can check (or ignore) 1302 * the new signal. YYY needs cleanup. 1303 */ 1304 if (lp == lwkt_preempted_proc()) { 1305 signotify(); 1306 } else if (lp->lwp_stat == LSRUN) { 1307 struct thread *td = lp->lwp_thread; 1308 struct proc *p __debugvar = lp->lwp_proc; 1309 1310 KASSERT(td != NULL, 1311 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1312 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1313 p->p_flag, lp->lwp_flag)); 1314 1315 /* 1316 * To prevent a MP race with TDF_SINTR we must 1317 * schedule the thread on the correct cpu. 1318 */ 1319 #ifdef SMP 1320 if (td->td_gd != mycpu) { 1321 LWPHOLD(lp); 1322 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1323 } else 1324 #endif 1325 if (td->td_flags & TDF_SINTR) 1326 lwkt_schedule(td); 1327 } 1328 } 1329 crit_exit(); 1330 } 1331 1332 #ifdef SMP 1333 1334 /* 1335 * This function is called via an IPI. We will be in a critical section but 1336 * the MP lock will NOT be held. The passed lp will be held. 1337 * 1338 * We must essentially repeat the code at the end of lwp_signotify(), 1339 * in particular rechecking all races. If we are still not on the 1340 * correct cpu we leave the lwp ref intact and continue the chase. 1341 * 1342 * XXX this may still not be entirely correct, since we are checking 1343 * lwp_stat asynchronously. 1344 */ 1345 static void 1346 signotify_remote(void *arg) 1347 { 1348 struct lwp *lp = arg; 1349 thread_t td; 1350 1351 if (lp == lwkt_preempted_proc()) { 1352 signotify(); 1353 } else if (lp->lwp_stat == LSRUN) { 1354 /* 1355 * To prevent a MP race with TDF_SINTR we must 1356 * schedule the thread on the correct cpu. 1357 */ 1358 td = lp->lwp_thread; 1359 if (td->td_gd != mycpu) { 1360 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1361 return; 1362 /* NOT REACHED */ 1363 } 1364 if (td->td_flags & TDF_SINTR) 1365 lwkt_schedule(td); 1366 } 1367 LWPRELE(lp); 1368 } 1369 1370 #endif 1371 1372 /* 1373 * Caller must hold p->p_token 1374 */ 1375 void 1376 proc_stop(struct proc *p) 1377 { 1378 struct lwp *lp; 1379 1380 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1381 crit_enter(); 1382 1383 /* If somebody raced us, be happy with it */ 1384 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1385 crit_exit(); 1386 return; 1387 } 1388 p->p_stat = SSTOP; 1389 1390 FOREACH_LWP_IN_PROC(lp, p) { 1391 switch (lp->lwp_stat) { 1392 case LSSTOP: 1393 /* 1394 * Do nothing, we are already counted in 1395 * p_nstopped. 1396 */ 1397 break; 1398 1399 case LSSLEEP: 1400 /* 1401 * We're sleeping, but we will stop before 1402 * returning to userspace, so count us 1403 * as stopped as well. We set LWP_WSTOP 1404 * to signal the lwp that it should not 1405 * increase p_nstopped when reaching tstop(). 1406 */ 1407 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1408 lp->lwp_flag |= LWP_WSTOP; 1409 ++p->p_nstopped; 1410 } 1411 break; 1412 1413 case LSRUN: 1414 /* 1415 * We might notify ourself, but that's not 1416 * a problem. 1417 */ 1418 lwp_signotify(lp); 1419 break; 1420 } 1421 } 1422 1423 if (p->p_nstopped == p->p_nthreads) { 1424 p->p_flag &= ~P_WAITED; 1425 wakeup(p->p_pptr); 1426 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1427 ksignal(p->p_pptr, SIGCHLD); 1428 } 1429 crit_exit(); 1430 } 1431 1432 /* 1433 * Caller must hold proc_token 1434 */ 1435 void 1436 proc_unstop(struct proc *p) 1437 { 1438 struct lwp *lp; 1439 1440 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1441 crit_enter(); 1442 1443 if (p->p_stat != SSTOP) { 1444 crit_exit(); 1445 return; 1446 } 1447 1448 p->p_stat = SACTIVE; 1449 1450 FOREACH_LWP_IN_PROC(lp, p) { 1451 switch (lp->lwp_stat) { 1452 case LSRUN: 1453 /* 1454 * Uh? Not stopped? Well, I guess that's okay. 1455 */ 1456 if (bootverbose) 1457 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1458 p->p_pid, lp->lwp_tid); 1459 break; 1460 1461 case LSSLEEP: 1462 /* 1463 * Still sleeping. Don't bother waking it up. 1464 * However, if this thread was counted as 1465 * stopped, undo this. 1466 * 1467 * Nevertheless we call setrunnable() so that it 1468 * will wake up in case a signal or timeout arrived 1469 * in the meantime. 1470 */ 1471 if (lp->lwp_flag & LWP_WSTOP) { 1472 lp->lwp_flag &= ~LWP_WSTOP; 1473 --p->p_nstopped; 1474 } else { 1475 if (bootverbose) 1476 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1477 p->p_pid, lp->lwp_tid); 1478 } 1479 /* FALLTHROUGH */ 1480 1481 case LSSTOP: 1482 setrunnable(lp); 1483 break; 1484 1485 } 1486 } 1487 crit_exit(); 1488 } 1489 1490 /* 1491 * No requirements. 1492 */ 1493 static int 1494 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1495 { 1496 sigset_t savedmask, set; 1497 struct proc *p = curproc; 1498 struct lwp *lp = curthread->td_lwp; 1499 int error, sig, hz, timevalid = 0; 1500 struct timespec rts, ets, ts; 1501 struct timeval tv; 1502 1503 error = 0; 1504 sig = 0; 1505 ets.tv_sec = 0; /* silence compiler warning */ 1506 ets.tv_nsec = 0; /* silence compiler warning */ 1507 SIG_CANTMASK(waitset); 1508 savedmask = lp->lwp_sigmask; 1509 1510 if (timeout) { 1511 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1512 timeout->tv_nsec < 1000000000) { 1513 timevalid = 1; 1514 getnanouptime(&rts); 1515 ets = rts; 1516 timespecadd(&ets, timeout); 1517 } 1518 } 1519 1520 for (;;) { 1521 set = lwp_sigpend(lp); 1522 SIGSETAND(set, waitset); 1523 if ((sig = sig_ffs(&set)) != 0) { 1524 SIGFILLSET(lp->lwp_sigmask); 1525 SIGDELSET(lp->lwp_sigmask, sig); 1526 SIG_CANTMASK(lp->lwp_sigmask); 1527 sig = issignal(lp, 1); 1528 /* 1529 * It may be a STOP signal, in the case, issignal 1530 * returns 0, because we may stop there, and new 1531 * signal can come in, we should restart if we got 1532 * nothing. 1533 */ 1534 if (sig == 0) 1535 continue; 1536 else 1537 break; 1538 } 1539 1540 /* 1541 * Previous checking got nothing, and we retried but still 1542 * got nothing, we should return the error status. 1543 */ 1544 if (error) 1545 break; 1546 1547 /* 1548 * POSIX says this must be checked after looking for pending 1549 * signals. 1550 */ 1551 if (timeout) { 1552 if (timevalid == 0) { 1553 error = EINVAL; 1554 break; 1555 } 1556 getnanouptime(&rts); 1557 if (timespeccmp(&rts, &ets, >=)) { 1558 error = EAGAIN; 1559 break; 1560 } 1561 ts = ets; 1562 timespecsub(&ts, &rts); 1563 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1564 hz = tvtohz_high(&tv); 1565 } else { 1566 hz = 0; 1567 } 1568 1569 lp->lwp_sigmask = savedmask; 1570 SIGSETNAND(lp->lwp_sigmask, waitset); 1571 /* 1572 * We won't ever be woken up. Instead, our sleep will 1573 * be broken in lwpsignal(). 1574 */ 1575 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1576 if (timeout) { 1577 if (error == ERESTART) { 1578 /* can not restart a timeout wait. */ 1579 error = EINTR; 1580 } else if (error == EAGAIN) { 1581 /* will calculate timeout by ourself. */ 1582 error = 0; 1583 } 1584 } 1585 /* Retry ... */ 1586 } 1587 1588 lp->lwp_sigmask = savedmask; 1589 if (sig) { 1590 error = 0; 1591 bzero(info, sizeof(*info)); 1592 info->si_signo = sig; 1593 lwp_delsig(lp, sig); /* take the signal! */ 1594 1595 if (sig == SIGKILL) { 1596 sigexit(lp, sig); 1597 /* NOT REACHED */ 1598 } 1599 } 1600 1601 return (error); 1602 } 1603 1604 /* 1605 * MPALMOSTSAFE 1606 */ 1607 int 1608 sys_sigtimedwait(struct sigtimedwait_args *uap) 1609 { 1610 struct timespec ts; 1611 struct timespec *timeout; 1612 sigset_t set; 1613 siginfo_t info; 1614 int error; 1615 1616 if (uap->timeout) { 1617 error = copyin(uap->timeout, &ts, sizeof(ts)); 1618 if (error) 1619 return (error); 1620 timeout = &ts; 1621 } else { 1622 timeout = NULL; 1623 } 1624 error = copyin(uap->set, &set, sizeof(set)); 1625 if (error) 1626 return (error); 1627 error = kern_sigtimedwait(set, &info, timeout); 1628 if (error) 1629 return (error); 1630 if (uap->info) 1631 error = copyout(&info, uap->info, sizeof(info)); 1632 /* Repost if we got an error. */ 1633 /* 1634 * XXX lwp 1635 * 1636 * This could transform a thread-specific signal to another 1637 * thread / process pending signal. 1638 */ 1639 if (error) { 1640 ksignal(curproc, info.si_signo); 1641 } else { 1642 uap->sysmsg_result = info.si_signo; 1643 } 1644 return (error); 1645 } 1646 1647 /* 1648 * MPALMOSTSAFE 1649 */ 1650 int 1651 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1652 { 1653 siginfo_t info; 1654 sigset_t set; 1655 int error; 1656 1657 error = copyin(uap->set, &set, sizeof(set)); 1658 if (error) 1659 return (error); 1660 error = kern_sigtimedwait(set, &info, NULL); 1661 if (error) 1662 return (error); 1663 if (uap->info) 1664 error = copyout(&info, uap->info, sizeof(info)); 1665 /* Repost if we got an error. */ 1666 /* 1667 * XXX lwp 1668 * 1669 * This could transform a thread-specific signal to another 1670 * thread / process pending signal. 1671 */ 1672 if (error) { 1673 ksignal(curproc, info.si_signo); 1674 } else { 1675 uap->sysmsg_result = info.si_signo; 1676 } 1677 return (error); 1678 } 1679 1680 /* 1681 * If the current process has received a signal that would interrupt a 1682 * system call, return EINTR or ERESTART as appropriate. 1683 */ 1684 int 1685 iscaught(struct lwp *lp) 1686 { 1687 struct proc *p = lp->lwp_proc; 1688 int sig; 1689 1690 if (p) { 1691 if ((sig = CURSIG(lp)) != 0) { 1692 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1693 return (EINTR); 1694 return (ERESTART); 1695 } 1696 } 1697 return(EWOULDBLOCK); 1698 } 1699 1700 /* 1701 * If the current process has received a signal (should be caught or cause 1702 * termination, should interrupt current syscall), return the signal number. 1703 * Stop signals with default action are processed immediately, then cleared; 1704 * they aren't returned. This is checked after each entry to the system for 1705 * a syscall or trap (though this can usually be done without calling issignal 1706 * by checking the pending signal masks in the CURSIG macro). 1707 * 1708 * This routine is called via CURSIG/__cursig. We will acquire and release 1709 * p->p_token but if the caller needs to interlock the test the caller must 1710 * also hold p->p_token. 1711 * 1712 * while (sig = CURSIG(curproc)) 1713 * postsig(sig); 1714 * 1715 * MPSAFE 1716 */ 1717 int 1718 issignal(struct lwp *lp, int maytrace) 1719 { 1720 struct proc *p = lp->lwp_proc; 1721 sigset_t mask; 1722 int sig, prop; 1723 1724 lwkt_gettoken(&p->p_token); 1725 1726 for (;;) { 1727 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1728 1729 /* 1730 * If this process is supposed to stop, stop this thread. 1731 */ 1732 if (p->p_stat == SSTOP) 1733 tstop(); 1734 1735 mask = lwp_sigpend(lp); 1736 SIGSETNAND(mask, lp->lwp_sigmask); 1737 if (p->p_flag & P_PPWAIT) 1738 SIG_STOPSIGMASK(mask); 1739 if (SIGISEMPTY(mask)) { /* no signal to send */ 1740 lwkt_reltoken(&p->p_token); 1741 return (0); 1742 } 1743 sig = sig_ffs(&mask); 1744 1745 STOPEVENT(p, S_SIG, sig); 1746 1747 /* 1748 * We should see pending but ignored signals 1749 * only if P_TRACED was on when they were posted. 1750 */ 1751 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1752 lwp_delsig(lp, sig); 1753 continue; 1754 } 1755 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1756 /* 1757 * If traced, always stop, and stay stopped until 1758 * released by the parent. 1759 * 1760 * NOTE: SSTOP may get cleared during the loop, 1761 * but we do not re-notify the parent if we have 1762 * to loop several times waiting for the parent 1763 * to let us continue. 1764 * 1765 * XXX not sure if this is still true 1766 */ 1767 p->p_xstat = sig; 1768 proc_stop(p); 1769 do { 1770 tstop(); 1771 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1772 1773 /* 1774 * If parent wants us to take the signal, 1775 * then it will leave it in p->p_xstat; 1776 * otherwise we just look for signals again. 1777 */ 1778 lwp_delsig(lp, sig); /* clear old signal */ 1779 sig = p->p_xstat; 1780 if (sig == 0) 1781 continue; 1782 1783 /* 1784 * Put the new signal into p_siglist. If the 1785 * signal is being masked, look for other signals. 1786 * 1787 * XXX lwp might need a call to ksignal() 1788 */ 1789 SIGADDSET(p->p_siglist, sig); 1790 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1791 continue; 1792 1793 /* 1794 * If the traced bit got turned off, go back up 1795 * to the top to rescan signals. This ensures 1796 * that p_sig* and ps_sigact are consistent. 1797 */ 1798 if ((p->p_flag & P_TRACED) == 0) 1799 continue; 1800 } 1801 1802 prop = sigprop(sig); 1803 1804 /* 1805 * Decide whether the signal should be returned. 1806 * Return the signal's number, or fall through 1807 * to clear it from the pending mask. 1808 */ 1809 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1810 case (intptr_t)SIG_DFL: 1811 /* 1812 * Don't take default actions on system processes. 1813 */ 1814 if (p->p_pid <= 1) { 1815 #ifdef DIAGNOSTIC 1816 /* 1817 * Are you sure you want to ignore SIGSEGV 1818 * in init? XXX 1819 */ 1820 kprintf("Process (pid %lu) got signal %d\n", 1821 (u_long)p->p_pid, sig); 1822 #endif 1823 break; /* == ignore */ 1824 } 1825 1826 /* 1827 * Handle the in-kernel checkpoint action 1828 */ 1829 if (prop & SA_CKPT) { 1830 checkpoint_signal_handler(lp); 1831 break; 1832 } 1833 1834 /* 1835 * If there is a pending stop signal to process 1836 * with default action, stop here, 1837 * then clear the signal. However, 1838 * if process is member of an orphaned 1839 * process group, ignore tty stop signals. 1840 */ 1841 if (prop & SA_STOP) { 1842 if (p->p_flag & P_TRACED || 1843 (p->p_pgrp->pg_jobc == 0 && 1844 prop & SA_TTYSTOP)) 1845 break; /* == ignore */ 1846 p->p_xstat = sig; 1847 proc_stop(p); 1848 tstop(); 1849 break; 1850 } else if (prop & SA_IGNORE) { 1851 /* 1852 * Except for SIGCONT, shouldn't get here. 1853 * Default action is to ignore; drop it. 1854 */ 1855 break; /* == ignore */ 1856 } else { 1857 lwkt_reltoken(&p->p_token); 1858 return (sig); 1859 } 1860 1861 /*NOTREACHED*/ 1862 1863 case (intptr_t)SIG_IGN: 1864 /* 1865 * Masking above should prevent us ever trying 1866 * to take action on an ignored signal other 1867 * than SIGCONT, unless process is traced. 1868 */ 1869 if ((prop & SA_CONT) == 0 && 1870 (p->p_flag & P_TRACED) == 0) 1871 kprintf("issignal\n"); 1872 break; /* == ignore */ 1873 1874 default: 1875 /* 1876 * This signal has an action, let 1877 * postsig() process it. 1878 */ 1879 lwkt_reltoken(&p->p_token); 1880 return (sig); 1881 } 1882 lwp_delsig(lp, sig); /* take the signal! */ 1883 } 1884 /* NOTREACHED */ 1885 } 1886 1887 /* 1888 * Take the action for the specified signal 1889 * from the current set of pending signals. 1890 */ 1891 void 1892 postsig(int sig) 1893 { 1894 struct lwp *lp = curthread->td_lwp; 1895 struct proc *p = lp->lwp_proc; 1896 struct sigacts *ps = p->p_sigacts; 1897 sig_t action; 1898 sigset_t returnmask; 1899 int code; 1900 1901 KASSERT(sig != 0, ("postsig")); 1902 1903 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1904 1905 /* 1906 * If we are a virtual kernel running an emulated user process 1907 * context, switch back to the virtual kernel context before 1908 * trying to post the signal. 1909 */ 1910 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1911 struct trapframe *tf = lp->lwp_md.md_regs; 1912 tf->tf_trapno = 0; 1913 vkernel_trap(lp, tf); 1914 } 1915 1916 lwp_delsig(lp, sig); 1917 action = ps->ps_sigact[_SIG_IDX(sig)]; 1918 #ifdef KTRACE 1919 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1920 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1921 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1922 #endif 1923 STOPEVENT(p, S_SIG, sig); 1924 1925 if (action == SIG_DFL) { 1926 /* 1927 * Default action, where the default is to kill 1928 * the process. (Other cases were ignored above.) 1929 */ 1930 sigexit(lp, sig); 1931 /* NOTREACHED */ 1932 } else { 1933 /* 1934 * If we get here, the signal must be caught. 1935 */ 1936 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1937 ("postsig action")); 1938 1939 crit_enter(); 1940 1941 /* 1942 * Reset the signal handler if asked to 1943 */ 1944 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1945 /* 1946 * See kern_sigaction() for origin of this code. 1947 */ 1948 SIGDELSET(p->p_sigcatch, sig); 1949 if (sig != SIGCONT && 1950 sigprop(sig) & SA_IGNORE) 1951 SIGADDSET(p->p_sigignore, sig); 1952 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1953 } 1954 1955 /* 1956 * Handle the mailbox case. Copyout to the appropriate 1957 * location but do not generate a signal frame. The system 1958 * call simply returns EINTR and the user is responsible for 1959 * polling the mailbox. 1960 */ 1961 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1962 int sig_copy = sig; 1963 copyout(&sig_copy, (void *)action, sizeof(int)); 1964 curproc->p_flag |= P_MAILBOX; 1965 crit_exit(); 1966 goto done; 1967 } 1968 1969 /* 1970 * Set the signal mask and calculate the mask to restore 1971 * when the signal function returns. 1972 * 1973 * Special case: user has done a sigsuspend. Here the 1974 * current mask is not of interest, but rather the 1975 * mask from before the sigsuspend is what we want 1976 * restored after the signal processing is completed. 1977 */ 1978 if (lp->lwp_flag & LWP_OLDMASK) { 1979 returnmask = lp->lwp_oldsigmask; 1980 lp->lwp_flag &= ~LWP_OLDMASK; 1981 } else { 1982 returnmask = lp->lwp_sigmask; 1983 } 1984 1985 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1986 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1987 SIGADDSET(lp->lwp_sigmask, sig); 1988 1989 crit_exit(); 1990 lp->lwp_ru.ru_nsignals++; 1991 if (lp->lwp_sig != sig) { 1992 code = 0; 1993 } else { 1994 code = lp->lwp_code; 1995 lp->lwp_code = 0; 1996 lp->lwp_sig = 0; 1997 } 1998 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1999 } 2000 done: 2001 ; 2002 } 2003 2004 /* 2005 * Kill the current process for stated reason. 2006 */ 2007 void 2008 killproc(struct proc *p, char *why) 2009 { 2010 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2011 p->p_pid, p->p_comm, 2012 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2013 ksignal(p, SIGKILL); 2014 } 2015 2016 /* 2017 * Force the current process to exit with the specified signal, dumping core 2018 * if appropriate. We bypass the normal tests for masked and caught signals, 2019 * allowing unrecoverable failures to terminate the process without changing 2020 * signal state. Mark the accounting record with the signal termination. 2021 * If dumping core, save the signal number for the debugger. Calls exit and 2022 * does not return. 2023 * 2024 * This routine does not return. 2025 */ 2026 void 2027 sigexit(struct lwp *lp, int sig) 2028 { 2029 struct proc *p = lp->lwp_proc; 2030 2031 p->p_acflag |= AXSIG; 2032 if (sigprop(sig) & SA_CORE) { 2033 lp->lwp_sig = sig; 2034 /* 2035 * Log signals which would cause core dumps 2036 * (Log as LOG_INFO to appease those who don't want 2037 * these messages.) 2038 * XXX : Todo, as well as euid, write out ruid too 2039 */ 2040 if (coredump(lp, sig) == 0) 2041 sig |= WCOREFLAG; 2042 if (kern_logsigexit) 2043 log(LOG_INFO, 2044 "pid %d (%s), uid %d: exited on signal %d%s\n", 2045 p->p_pid, p->p_comm, 2046 p->p_ucred ? p->p_ucred->cr_uid : -1, 2047 sig &~ WCOREFLAG, 2048 sig & WCOREFLAG ? " (core dumped)" : ""); 2049 } 2050 exit1(W_EXITCODE(0, sig)); 2051 /* NOTREACHED */ 2052 } 2053 2054 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2055 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2056 sizeof(corefilename), "process corefile name format string"); 2057 2058 /* 2059 * expand_name(name, uid, pid) 2060 * Expand the name described in corefilename, using name, uid, and pid. 2061 * corefilename is a kprintf-like string, with three format specifiers: 2062 * %N name of process ("name") 2063 * %P process id (pid) 2064 * %U user id (uid) 2065 * For example, "%N.core" is the default; they can be disabled completely 2066 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2067 * This is controlled by the sysctl variable kern.corefile (see above). 2068 */ 2069 2070 static char * 2071 expand_name(const char *name, uid_t uid, pid_t pid) 2072 { 2073 char *temp; 2074 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2075 int i, n; 2076 char *format = corefilename; 2077 size_t namelen; 2078 2079 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2080 if (temp == NULL) 2081 return NULL; 2082 namelen = strlen(name); 2083 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2084 int l; 2085 switch (format[i]) { 2086 case '%': /* Format character */ 2087 i++; 2088 switch (format[i]) { 2089 case '%': 2090 temp[n++] = '%'; 2091 break; 2092 case 'N': /* process name */ 2093 if ((n + namelen) > MAXPATHLEN) { 2094 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2095 pid, name, uid, temp, name); 2096 kfree(temp, M_TEMP); 2097 return NULL; 2098 } 2099 memcpy(temp+n, name, namelen); 2100 n += namelen; 2101 break; 2102 case 'P': /* process id */ 2103 l = ksprintf(buf, "%u", pid); 2104 if ((n + l) > MAXPATHLEN) { 2105 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2106 pid, name, uid, temp, name); 2107 kfree(temp, M_TEMP); 2108 return NULL; 2109 } 2110 memcpy(temp+n, buf, l); 2111 n += l; 2112 break; 2113 case 'U': /* user id */ 2114 l = ksprintf(buf, "%u", uid); 2115 if ((n + l) > MAXPATHLEN) { 2116 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2117 pid, name, uid, temp, name); 2118 kfree(temp, M_TEMP); 2119 return NULL; 2120 } 2121 memcpy(temp+n, buf, l); 2122 n += l; 2123 break; 2124 default: 2125 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2126 } 2127 break; 2128 default: 2129 temp[n++] = format[i]; 2130 } 2131 } 2132 temp[n] = '\0'; 2133 return temp; 2134 } 2135 2136 /* 2137 * Dump a process' core. The main routine does some 2138 * policy checking, and creates the name of the coredump; 2139 * then it passes on a vnode and a size limit to the process-specific 2140 * coredump routine if there is one; if there _is not_ one, it returns 2141 * ENOSYS; otherwise it returns the error from the process-specific routine. 2142 * 2143 * The parameter `lp' is the lwp which triggered the coredump. 2144 */ 2145 2146 static int 2147 coredump(struct lwp *lp, int sig) 2148 { 2149 struct proc *p = lp->lwp_proc; 2150 struct vnode *vp; 2151 struct ucred *cred = p->p_ucred; 2152 struct flock lf; 2153 struct nlookupdata nd; 2154 struct vattr vattr; 2155 int error, error1; 2156 char *name; /* name of corefile */ 2157 off_t limit; 2158 2159 STOPEVENT(p, S_CORE, 0); 2160 2161 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2162 return (EFAULT); 2163 2164 /* 2165 * Note that the bulk of limit checking is done after 2166 * the corefile is created. The exception is if the limit 2167 * for corefiles is 0, in which case we don't bother 2168 * creating the corefile at all. This layout means that 2169 * a corefile is truncated instead of not being created, 2170 * if it is larger than the limit. 2171 */ 2172 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2173 if (limit == 0) 2174 return EFBIG; 2175 2176 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2177 if (name == NULL) 2178 return (EINVAL); 2179 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2180 if (error == 0) 2181 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2182 kfree(name, M_TEMP); 2183 if (error) { 2184 nlookup_done(&nd); 2185 return (error); 2186 } 2187 vp = nd.nl_open_vp; 2188 nd.nl_open_vp = NULL; 2189 nlookup_done(&nd); 2190 2191 vn_unlock(vp); 2192 lf.l_whence = SEEK_SET; 2193 lf.l_start = 0; 2194 lf.l_len = 0; 2195 lf.l_type = F_WRLCK; 2196 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2197 if (error) 2198 goto out2; 2199 2200 /* Don't dump to non-regular files or files with links. */ 2201 if (vp->v_type != VREG || 2202 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2203 error = EFAULT; 2204 goto out1; 2205 } 2206 2207 /* Don't dump to files current user does not own */ 2208 if (vattr.va_uid != p->p_ucred->cr_uid) { 2209 error = EFAULT; 2210 goto out1; 2211 } 2212 2213 VATTR_NULL(&vattr); 2214 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2215 vattr.va_size = 0; 2216 VOP_SETATTR(vp, &vattr, cred); 2217 p->p_acflag |= ACORE; 2218 vn_unlock(vp); 2219 2220 error = p->p_sysent->sv_coredump ? 2221 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2222 2223 out1: 2224 lf.l_type = F_UNLCK; 2225 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2226 out2: 2227 error1 = vn_close(vp, FWRITE); 2228 if (error == 0) 2229 error = error1; 2230 return (error); 2231 } 2232 2233 /* 2234 * Nonexistent system call-- signal process (may want to handle it). 2235 * Flag error in case process won't see signal immediately (blocked or ignored). 2236 * 2237 * MPALMOSTSAFE 2238 */ 2239 /* ARGSUSED */ 2240 int 2241 sys_nosys(struct nosys_args *args) 2242 { 2243 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2244 return (EINVAL); 2245 } 2246 2247 /* 2248 * Send a SIGIO or SIGURG signal to a process or process group using 2249 * stored credentials rather than those of the current process. 2250 */ 2251 void 2252 pgsigio(struct sigio *sigio, int sig, int checkctty) 2253 { 2254 if (sigio == NULL) 2255 return; 2256 2257 if (sigio->sio_pgid > 0) { 2258 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2259 sigio->sio_proc)) 2260 ksignal(sigio->sio_proc, sig); 2261 } else if (sigio->sio_pgid < 0) { 2262 struct proc *p; 2263 2264 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 2265 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 2266 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2267 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2268 ksignal(p, sig); 2269 } 2270 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 2271 } 2272 } 2273 2274 static int 2275 filt_sigattach(struct knote *kn) 2276 { 2277 struct proc *p = curproc; 2278 2279 kn->kn_ptr.p_proc = p; 2280 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2281 2282 /* XXX lock the proc here while adding to the list? */ 2283 knote_insert(&p->p_klist, kn); 2284 2285 return (0); 2286 } 2287 2288 static void 2289 filt_sigdetach(struct knote *kn) 2290 { 2291 struct proc *p = kn->kn_ptr.p_proc; 2292 2293 knote_remove(&p->p_klist, kn); 2294 } 2295 2296 /* 2297 * signal knotes are shared with proc knotes, so we apply a mask to 2298 * the hint in order to differentiate them from process hints. This 2299 * could be avoided by using a signal-specific knote list, but probably 2300 * isn't worth the trouble. 2301 */ 2302 static int 2303 filt_signal(struct knote *kn, long hint) 2304 { 2305 if (hint & NOTE_SIGNAL) { 2306 hint &= ~NOTE_SIGNAL; 2307 2308 if (kn->kn_id == hint) 2309 kn->kn_data++; 2310 } 2311 return (kn->kn_data != 0); 2312 } 2313