1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 * $DragonFly: src/sys/kern/kern_sig.c,v 1.34 2005/02/20 01:17:44 davidxu Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/sysproto.h> 49 #include <sys/signalvar.h> 50 #include <sys/resourcevar.h> 51 #include <sys/vnode.h> 52 #include <sys/event.h> 53 #include <sys/proc.h> 54 #include <sys/nlookup.h> 55 #include <sys/pioctl.h> 56 #include <sys/systm.h> 57 #include <sys/acct.h> 58 #include <sys/fcntl.h> 59 #include <sys/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/unistd.h> 67 #include <sys/kern_syscall.h> 68 69 70 #include <machine/ipl.h> 71 #include <machine/cpu.h> 72 #include <machine/smp.h> 73 74 static int coredump(struct proc *); 75 static char *expand_name(const char *, uid_t, pid_t); 76 static int killpg(int sig, int pgid, int all); 77 static int sig_ffs(sigset_t *set); 78 static int sigprop(int sig); 79 static void stop(struct proc *); 80 #ifdef SMP 81 static void signotify_remote(void *arg); 82 #endif 83 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 84 struct timespec *timeout); 85 86 static int filt_sigattach(struct knote *kn); 87 static void filt_sigdetach(struct knote *kn); 88 static int filt_signal(struct knote *kn, long hint); 89 90 struct filterops sig_filtops = 91 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 92 93 static int kern_logsigexit = 1; 94 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 95 &kern_logsigexit, 0, 96 "Log processes quitting on abnormal signals to syslog(3)"); 97 98 /* 99 * Can process p, with pcred pc, send the signal sig to process q? 100 */ 101 #define CANSIGNAL(q, sig) \ 102 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 103 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 104 105 /* 106 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 107 */ 108 #define CANSIGIO(ruid, uc, q) \ 109 ((uc)->cr_uid == 0 || \ 110 (ruid) == (q)->p_ucred->cr_ruid || \ 111 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 112 (ruid) == (q)->p_ucred->cr_uid || \ 113 (uc)->cr_uid == (q)->p_ucred->cr_uid) 114 115 int sugid_coredump; 116 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 117 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 118 119 static int do_coredump = 1; 120 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 121 &do_coredump, 0, "Enable/Disable coredumps"); 122 123 /* 124 * Signal properties and actions. 125 * The array below categorizes the signals and their default actions 126 * according to the following properties: 127 */ 128 #define SA_KILL 0x01 /* terminates process by default */ 129 #define SA_CORE 0x02 /* ditto and coredumps */ 130 #define SA_STOP 0x04 /* suspend process */ 131 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 132 #define SA_IGNORE 0x10 /* ignore by default */ 133 #define SA_CONT 0x20 /* continue if suspended */ 134 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 135 #define SA_CKPT 0x80 /* checkpoint process */ 136 137 138 static int sigproptbl[NSIG] = { 139 SA_KILL, /* SIGHUP */ 140 SA_KILL, /* SIGINT */ 141 SA_KILL|SA_CORE, /* SIGQUIT */ 142 SA_KILL|SA_CORE, /* SIGILL */ 143 SA_KILL|SA_CORE, /* SIGTRAP */ 144 SA_KILL|SA_CORE, /* SIGABRT */ 145 SA_KILL|SA_CORE, /* SIGEMT */ 146 SA_KILL|SA_CORE, /* SIGFPE */ 147 SA_KILL, /* SIGKILL */ 148 SA_KILL|SA_CORE, /* SIGBUS */ 149 SA_KILL|SA_CORE, /* SIGSEGV */ 150 SA_KILL|SA_CORE, /* SIGSYS */ 151 SA_KILL, /* SIGPIPE */ 152 SA_KILL, /* SIGALRM */ 153 SA_KILL, /* SIGTERM */ 154 SA_IGNORE, /* SIGURG */ 155 SA_STOP, /* SIGSTOP */ 156 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 157 SA_IGNORE|SA_CONT, /* SIGCONT */ 158 SA_IGNORE, /* SIGCHLD */ 159 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 161 SA_IGNORE, /* SIGIO */ 162 SA_KILL, /* SIGXCPU */ 163 SA_KILL, /* SIGXFSZ */ 164 SA_KILL, /* SIGVTALRM */ 165 SA_KILL, /* SIGPROF */ 166 SA_IGNORE, /* SIGWINCH */ 167 SA_IGNORE, /* SIGINFO */ 168 SA_KILL, /* SIGUSR1 */ 169 SA_KILL, /* SIGUSR2 */ 170 SA_IGNORE, /* SIGTHR */ 171 SA_CKPT, /* SIGCKPT */ 172 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 173 SA_IGNORE, 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 204 }; 205 206 static __inline int 207 sigprop(int sig) 208 { 209 210 if (sig > 0 && sig < NSIG) 211 return (sigproptbl[_SIG_IDX(sig)]); 212 return (0); 213 } 214 215 static __inline int 216 sig_ffs(sigset_t *set) 217 { 218 int i; 219 220 for (i = 0; i < _SIG_WORDS; i++) 221 if (set->__bits[i]) 222 return (ffs(set->__bits[i]) + (i * 32)); 223 return (0); 224 } 225 226 int 227 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 228 { 229 struct thread *td = curthread; 230 struct proc *p = td->td_proc; 231 struct sigacts *ps = p->p_sigacts; 232 233 if (sig <= 0 || sig > _SIG_MAXSIG) 234 return (EINVAL); 235 236 if (oact) { 237 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 238 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 239 oact->sa_flags = 0; 240 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 241 oact->sa_flags |= SA_ONSTACK; 242 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 243 oact->sa_flags |= SA_RESTART; 244 if (SIGISMEMBER(ps->ps_sigreset, sig)) 245 oact->sa_flags |= SA_RESETHAND; 246 if (SIGISMEMBER(ps->ps_signodefer, sig)) 247 oact->sa_flags |= SA_NODEFER; 248 if (SIGISMEMBER(ps->ps_siginfo, sig)) 249 oact->sa_flags |= SA_SIGINFO; 250 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) 251 oact->sa_flags |= SA_NOCLDSTOP; 252 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) 253 oact->sa_flags |= SA_NOCLDWAIT; 254 } 255 if (act) { 256 if ((sig == SIGKILL || sig == SIGSTOP) && 257 act->sa_handler != SIG_DFL) 258 return (EINVAL); 259 260 /* 261 * Change setting atomically. 262 */ 263 splhigh(); 264 265 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 266 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 267 if (act->sa_flags & SA_SIGINFO) { 268 ps->ps_sigact[_SIG_IDX(sig)] = 269 (__sighandler_t *)act->sa_sigaction; 270 SIGADDSET(ps->ps_siginfo, sig); 271 } else { 272 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 273 SIGDELSET(ps->ps_siginfo, sig); 274 } 275 if (!(act->sa_flags & SA_RESTART)) 276 SIGADDSET(ps->ps_sigintr, sig); 277 else 278 SIGDELSET(ps->ps_sigintr, sig); 279 if (act->sa_flags & SA_ONSTACK) 280 SIGADDSET(ps->ps_sigonstack, sig); 281 else 282 SIGDELSET(ps->ps_sigonstack, sig); 283 if (act->sa_flags & SA_RESETHAND) 284 SIGADDSET(ps->ps_sigreset, sig); 285 else 286 SIGDELSET(ps->ps_sigreset, sig); 287 if (act->sa_flags & SA_NODEFER) 288 SIGADDSET(ps->ps_signodefer, sig); 289 else 290 SIGDELSET(ps->ps_signodefer, sig); 291 if (sig == SIGCHLD) { 292 if (act->sa_flags & SA_NOCLDSTOP) 293 p->p_procsig->ps_flag |= PS_NOCLDSTOP; 294 else 295 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; 296 if (act->sa_flags & SA_NOCLDWAIT) { 297 /* 298 * Paranoia: since SA_NOCLDWAIT is implemented 299 * by reparenting the dying child to PID 1 (and 300 * trust it to reap the zombie), PID 1 itself 301 * is forbidden to set SA_NOCLDWAIT. 302 */ 303 if (p->p_pid == 1) 304 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 305 else 306 p->p_procsig->ps_flag |= PS_NOCLDWAIT; 307 } else { 308 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 309 } 310 } 311 /* 312 * Set bit in p_sigignore for signals that are set to SIG_IGN, 313 * and for signals set to SIG_DFL where the default is to 314 * ignore. However, don't put SIGCONT in p_sigignore, as we 315 * have to restart the process. 316 */ 317 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 318 (sigprop(sig) & SA_IGNORE && 319 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 320 /* never to be seen again */ 321 SIGDELSET(p->p_siglist, sig); 322 if (sig != SIGCONT) 323 /* easier in psignal */ 324 SIGADDSET(p->p_sigignore, sig); 325 SIGDELSET(p->p_sigcatch, sig); 326 } else { 327 SIGDELSET(p->p_sigignore, sig); 328 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 329 SIGDELSET(p->p_sigcatch, sig); 330 else 331 SIGADDSET(p->p_sigcatch, sig); 332 } 333 334 spl0(); 335 } 336 return (0); 337 } 338 339 int 340 sigaction(struct sigaction_args *uap) 341 { 342 struct sigaction act, oact; 343 struct sigaction *actp, *oactp; 344 int error; 345 346 actp = (uap->act != NULL) ? &act : NULL; 347 oactp = (uap->oact != NULL) ? &oact : NULL; 348 if (actp) { 349 error = copyin(uap->act, actp, sizeof(act)); 350 if (error) 351 return (error); 352 } 353 error = kern_sigaction(uap->sig, actp, oactp); 354 if (oactp && !error) { 355 error = copyout(oactp, uap->oact, sizeof(oact)); 356 } 357 return (error); 358 } 359 360 /* 361 * Initialize signal state for process 0; 362 * set to ignore signals that are ignored by default. 363 */ 364 void 365 siginit(struct proc *p) 366 { 367 int i; 368 369 for (i = 1; i <= NSIG; i++) 370 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 371 SIGADDSET(p->p_sigignore, i); 372 } 373 374 /* 375 * Reset signals for an exec of the specified process. 376 */ 377 void 378 execsigs(struct proc *p) 379 { 380 struct sigacts *ps = p->p_sigacts; 381 int sig; 382 383 /* 384 * Reset caught signals. Held signals remain held 385 * through p_sigmask (unless they were caught, 386 * and are now ignored by default). 387 */ 388 while (SIGNOTEMPTY(p->p_sigcatch)) { 389 sig = sig_ffs(&p->p_sigcatch); 390 SIGDELSET(p->p_sigcatch, sig); 391 if (sigprop(sig) & SA_IGNORE) { 392 if (sig != SIGCONT) 393 SIGADDSET(p->p_sigignore, sig); 394 SIGDELSET(p->p_siglist, sig); 395 } 396 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 397 } 398 /* 399 * Reset stack state to the user stack. 400 * Clear set of signals caught on the signal stack. 401 */ 402 p->p_sigstk.ss_flags = SS_DISABLE; 403 p->p_sigstk.ss_size = 0; 404 p->p_sigstk.ss_sp = 0; 405 p->p_flag &= ~P_ALTSTACK; 406 /* 407 * Reset no zombies if child dies flag as Solaris does. 408 */ 409 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 410 } 411 412 /* 413 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 414 * 415 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 416 * p == curproc. Also remember that in order to remain MP SAFE 417 * no spl*() calls may be made. 418 */ 419 int 420 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 421 { 422 struct thread *td = curthread; 423 struct proc *p = td->td_proc; 424 int error; 425 426 if (oset != NULL) 427 *oset = p->p_sigmask; 428 429 error = 0; 430 if (set != NULL) { 431 switch (how) { 432 case SIG_BLOCK: 433 SIG_CANTMASK(*set); 434 SIGSETOR(p->p_sigmask, *set); 435 break; 436 case SIG_UNBLOCK: 437 SIGSETNAND(p->p_sigmask, *set); 438 break; 439 case SIG_SETMASK: 440 SIG_CANTMASK(*set); 441 p->p_sigmask = *set; 442 break; 443 default: 444 error = EINVAL; 445 break; 446 } 447 } 448 return (error); 449 } 450 451 /* 452 * sigprocmask() - MP SAFE 453 */ 454 int 455 sigprocmask(struct sigprocmask_args *uap) 456 { 457 sigset_t set, oset; 458 sigset_t *setp, *osetp; 459 int error; 460 461 setp = (uap->set != NULL) ? &set : NULL; 462 osetp = (uap->oset != NULL) ? &oset : NULL; 463 if (setp) { 464 error = copyin(uap->set, setp, sizeof(set)); 465 if (error) 466 return (error); 467 } 468 error = kern_sigprocmask(uap->how, setp, osetp); 469 if (osetp && !error) { 470 error = copyout(osetp, uap->oset, sizeof(oset)); 471 } 472 return (error); 473 } 474 475 int 476 kern_sigpending(struct __sigset *set) 477 { 478 struct thread *td = curthread; 479 struct proc *p = td->td_proc; 480 481 *set = p->p_siglist; 482 483 return (0); 484 } 485 486 int 487 sigpending(struct sigpending_args *uap) 488 { 489 sigset_t set; 490 int error; 491 492 error = kern_sigpending(&set); 493 494 if (error == 0) 495 error = copyout(&set, uap->set, sizeof(set)); 496 return (error); 497 } 498 499 /* 500 * Suspend process until signal, providing mask to be set 501 * in the meantime. 502 */ 503 int 504 kern_sigsuspend(struct __sigset *set) 505 { 506 struct thread *td = curthread; 507 struct proc *p = td->td_proc; 508 struct sigacts *ps = p->p_sigacts; 509 510 /* 511 * When returning from sigsuspend, we want 512 * the old mask to be restored after the 513 * signal handler has finished. Thus, we 514 * save it here and mark the sigacts structure 515 * to indicate this. 516 */ 517 p->p_oldsigmask = p->p_sigmask; 518 p->p_flag |= P_OLDMASK; 519 520 SIG_CANTMASK(*set); 521 p->p_sigmask = *set; 522 while (tsleep(ps, PCATCH, "pause", 0) == 0) 523 /* void */; 524 /* always return EINTR rather than ERESTART... */ 525 return (EINTR); 526 } 527 528 /* 529 * Note nonstandard calling convention: libc stub passes mask, not 530 * pointer, to save a copyin. 531 */ 532 int 533 sigsuspend(struct sigsuspend_args *uap) 534 { 535 sigset_t mask; 536 int error; 537 538 error = copyin(uap->sigmask, &mask, sizeof(mask)); 539 if (error) 540 return (error); 541 542 error = kern_sigsuspend(&mask); 543 544 return (error); 545 } 546 547 int 548 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 549 { 550 struct thread *td = curthread; 551 struct proc *p = td->td_proc; 552 553 if ((p->p_flag & P_ALTSTACK) == 0) 554 p->p_sigstk.ss_flags |= SS_DISABLE; 555 556 if (oss) 557 *oss = p->p_sigstk; 558 559 if (ss) { 560 if (ss->ss_flags & SS_DISABLE) { 561 if (p->p_sigstk.ss_flags & SS_ONSTACK) 562 return (EINVAL); 563 p->p_flag &= ~P_ALTSTACK; 564 p->p_sigstk.ss_flags = ss->ss_flags; 565 } else { 566 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 567 return (ENOMEM); 568 p->p_flag |= P_ALTSTACK; 569 p->p_sigstk = *ss; 570 } 571 } 572 573 return (0); 574 } 575 576 int 577 sigaltstack(struct sigaltstack_args *uap) 578 { 579 stack_t ss, oss; 580 int error; 581 582 if (uap->ss) { 583 error = copyin(uap->ss, &ss, sizeof(ss)); 584 if (error) 585 return (error); 586 } 587 588 error = kern_sigaltstack(uap->ss ? &ss : NULL, 589 uap->oss ? &oss : NULL); 590 591 if (error == 0 && uap->oss) 592 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 593 return (error); 594 } 595 596 /* 597 * Common code for kill process group/broadcast kill. 598 * cp is calling process. 599 */ 600 static int 601 killpg(int sig, int pgid, int all) 602 { 603 struct proc *cp = curproc; 604 struct proc *p; 605 struct pgrp *pgrp; 606 int nfound = 0; 607 608 if (all) { 609 /* 610 * broadcast 611 */ 612 FOREACH_PROC_IN_SYSTEM(p) { 613 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 614 p == cp || !CANSIGNAL(p, sig)) 615 continue; 616 nfound++; 617 if (sig) 618 psignal(p, sig); 619 } 620 } else { 621 if (pgid == 0) { 622 /* 623 * zero pgid means send to my process group. 624 */ 625 pgrp = cp->p_pgrp; 626 } else { 627 pgrp = pgfind(pgid); 628 if (pgrp == NULL) 629 return (ESRCH); 630 } 631 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 632 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 633 p->p_stat == SZOMB || 634 !CANSIGNAL(p, sig)) 635 continue; 636 nfound++; 637 if (sig) 638 psignal(p, sig); 639 } 640 } 641 return (nfound ? 0 : ESRCH); 642 } 643 644 int 645 kern_kill(int sig, int pid) 646 { 647 struct thread *td = curthread; 648 struct proc *p = td->td_proc; 649 650 if ((u_int)sig > _SIG_MAXSIG) 651 return (EINVAL); 652 if (pid > 0) { 653 /* kill single process */ 654 if ((p = pfind(pid)) == NULL) 655 return (ESRCH); 656 if (!CANSIGNAL(p, sig)) 657 return (EPERM); 658 if (sig) 659 psignal(p, sig); 660 return (0); 661 } 662 switch (pid) { 663 case -1: /* broadcast signal */ 664 return (killpg(sig, 0, 1)); 665 case 0: /* signal own process group */ 666 return (killpg(sig, 0, 0)); 667 default: /* negative explicit process group */ 668 return (killpg(sig, -pid, 0)); 669 } 670 /* NOTREACHED */ 671 } 672 673 int 674 kill(struct kill_args *uap) 675 { 676 int error; 677 678 error = kern_kill(uap->signum, uap->pid); 679 680 return (error); 681 } 682 683 /* 684 * Send a signal to a process group. 685 */ 686 void 687 gsignal(int pgid, int sig) 688 { 689 struct pgrp *pgrp; 690 691 if (pgid && (pgrp = pgfind(pgid))) 692 pgsignal(pgrp, sig, 0); 693 } 694 695 /* 696 * Send a signal to a process group. If checktty is 1, 697 * limit to members which have a controlling terminal. 698 */ 699 void 700 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 701 { 702 struct proc *p; 703 704 if (pgrp) 705 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) 706 if (checkctty == 0 || p->p_flag & P_CONTROLT) 707 psignal(p, sig); 708 } 709 710 /* 711 * Send a signal caused by a trap to the current process. 712 * If it will be caught immediately, deliver it with correct code. 713 * Otherwise, post it normally. 714 */ 715 void 716 trapsignal(struct proc *p, int sig, u_long code) 717 { 718 struct sigacts *ps = p->p_sigacts; 719 720 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 721 !SIGISMEMBER(p->p_sigmask, sig)) { 722 p->p_stats->p_ru.ru_nsignals++; 723 #ifdef KTRACE 724 if (KTRPOINT(p->p_thread, KTR_PSIG)) 725 ktrpsig(p->p_tracep, sig, ps->ps_sigact[_SIG_IDX(sig)], 726 &p->p_sigmask, code); 727 #endif 728 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 729 &p->p_sigmask, code); 730 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 731 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 732 SIGADDSET(p->p_sigmask, sig); 733 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 734 /* 735 * See kern_sigaction() for origin of this code. 736 */ 737 SIGDELSET(p->p_sigcatch, sig); 738 if (sig != SIGCONT && 739 sigprop(sig) & SA_IGNORE) 740 SIGADDSET(p->p_sigignore, sig); 741 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 742 } 743 } else { 744 p->p_code = code; /* XXX for core dump/debugger */ 745 p->p_sig = sig; /* XXX to verify code */ 746 psignal(p, sig); 747 } 748 } 749 750 /* 751 * Send the signal to the process. If the signal has an action, the action 752 * is usually performed by the target process rather than the caller; we add 753 * the signal to the set of pending signals for the process. 754 * 755 * Exceptions: 756 * o When a stop signal is sent to a sleeping process that takes the 757 * default action, the process is stopped without awakening it. 758 * o SIGCONT restarts stopped processes (or puts them back to sleep) 759 * regardless of the signal action (eg, blocked or ignored). 760 * 761 * Other ignored signals are discarded immediately. 762 */ 763 764 /* 765 * temporary hack to allow checkpoint code to continue to 766 * be in a module for the moment 767 */ 768 769 void 770 psignal(struct proc *p, int sig) 771 { 772 int s, prop; 773 sig_t action; 774 775 if (sig > _SIG_MAXSIG || sig <= 0) { 776 printf("psignal: signal %d\n", sig); 777 panic("psignal signal number"); 778 } 779 780 s = splhigh(); 781 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 782 splx(s); 783 784 prop = sigprop(sig); 785 786 /* 787 * If proc is traced, always give parent a chance; 788 * if signal event is tracked by procfs, give *that* 789 * a chance, as well. 790 */ 791 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 792 action = SIG_DFL; 793 } else { 794 /* 795 * If the signal is being ignored, 796 * then we forget about it immediately. 797 * (Note: we don't set SIGCONT in p_sigignore, 798 * and if it is set to SIG_IGN, 799 * action will be SIG_DFL here.) 800 */ 801 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 802 return; 803 if (SIGISMEMBER(p->p_sigmask, sig)) 804 action = SIG_HOLD; 805 else if (SIGISMEMBER(p->p_sigcatch, sig)) 806 action = SIG_CATCH; 807 else 808 action = SIG_DFL; 809 } 810 811 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 812 (p->p_flag & P_TRACED) == 0) { 813 p->p_nice = NZERO; 814 } 815 816 if (prop & SA_CONT) 817 SIG_STOPSIGMASK(p->p_siglist); 818 819 820 if (prop & SA_STOP) { 821 /* 822 * If sending a tty stop signal to a member of an orphaned 823 * process group, discard the signal here if the action 824 * is default; don't stop the process below if sleeping, 825 * and don't clear any pending SIGCONT. 826 */ 827 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 828 action == SIG_DFL) { 829 return; 830 } 831 SIG_CONTSIGMASK(p->p_siglist); 832 } 833 SIGADDSET(p->p_siglist, sig); 834 835 /* 836 * Defer further processing for signals which are held, 837 * except that stopped processes must be continued by SIGCONT. 838 */ 839 if (action == SIG_HOLD && (!(prop & SA_CONT) || p->p_stat != SSTOP)) 840 return; 841 s = splhigh(); 842 switch (p->p_stat) { 843 case SSLEEP: 844 /* 845 * If process is sleeping uninterruptibly 846 * we can't interrupt the sleep... the signal will 847 * be noticed when the process returns through 848 * trap() or syscall(). 849 */ 850 if ((p->p_flag & P_SINTR) == 0) 851 goto out; 852 /* 853 * Process is sleeping and traced... make it runnable 854 * so it can discover the signal in issignal() and stop 855 * for the parent. 856 */ 857 if (p->p_flag & P_TRACED) 858 goto run; 859 /* 860 * If SIGCONT is default (or ignored) and process is 861 * asleep, we are finished; the process should not 862 * be awakened. 863 */ 864 if ((prop & SA_CONT) && action == SIG_DFL) { 865 SIGDELSET(p->p_siglist, sig); 866 goto out; 867 } 868 /* 869 * When a sleeping process receives a stop 870 * signal, process immediately if possible. 871 * All other (caught or default) signals 872 * cause the process to run. 873 */ 874 if (prop & SA_STOP) { 875 if (action != SIG_DFL) 876 goto run; 877 /* 878 * If a child holding parent blocked, 879 * stopping could cause deadlock. 880 */ 881 if (p->p_flag & P_PPWAIT) 882 goto out; 883 SIGDELSET(p->p_siglist, sig); 884 p->p_xstat = sig; 885 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 886 psignal(p->p_pptr, SIGCHLD); 887 stop(p); 888 goto out; 889 } else { 890 goto run; 891 } 892 /*NOTREACHED*/ 893 case SSTOP: 894 /* 895 * If traced process is already stopped, 896 * then no further action is necessary. 897 */ 898 if (p->p_flag & P_TRACED) 899 goto out; 900 901 /* 902 * Kill signal always sets processes running. 903 */ 904 if (sig == SIGKILL) 905 goto run; 906 907 if (prop & SA_CONT) { 908 /* 909 * If SIGCONT is default (or ignored), we continue the 910 * process but don't leave the signal in p_siglist, as 911 * it has no further action. If SIGCONT is held, we 912 * continue the process and leave the signal in 913 * p_siglist. If the process catches SIGCONT, let it 914 * handle the signal itself. If it isn't waiting on 915 * an event, then it goes back to run state. 916 * Otherwise, process goes back to sleep state. 917 */ 918 if (action == SIG_DFL) 919 SIGDELSET(p->p_siglist, sig); 920 if (action == SIG_CATCH) 921 goto run; 922 if (p->p_wchan == 0) 923 goto run; 924 clrrunnable(p, SSLEEP); 925 goto out; 926 } 927 928 if (prop & SA_STOP) { 929 /* 930 * Already stopped, don't need to stop again. 931 * (If we did the shell could get confused.) 932 */ 933 SIGDELSET(p->p_siglist, sig); 934 goto out; 935 } 936 937 /* 938 * If process is sleeping interruptibly, then simulate a 939 * wakeup so that when it is continued, it will be made 940 * runnable and can look at the signal. But don't make 941 * the process runnable, leave it stopped. 942 */ 943 if (p->p_wchan && (p->p_flag & P_SINTR)) 944 unsleep(p->p_thread); 945 goto out; 946 default: 947 /* 948 * SRUN, SIDL, SZOMB do nothing with the signal, 949 * other than kicking ourselves if we are running. 950 * It will either never be noticed, or noticed very soon. 951 * 952 * Note that p_thread may be NULL or may not be completely 953 * initialized if the process is in the SIDL or SZOMB state. 954 * 955 * For SMP we may have to forward the request to another cpu. 956 * YYY the MP lock prevents the target process from moving 957 * to another cpu, see kern/kern_switch.c 958 * 959 * If the target thread is waiting on its message port, 960 * wakeup the target thread so it can check (or ignore) 961 * the new signal. YYY needs cleanup. 962 */ 963 #ifdef SMP 964 if (p == lwkt_preempted_proc()) { 965 signotify(); 966 } else if (p->p_stat == SRUN) { 967 struct thread *td = p->p_thread; 968 969 KASSERT(td != NULL, 970 ("pid %d NULL p_thread stat %d flags %08x", 971 p->p_pid, p->p_stat, p->p_flag)); 972 973 if (td->td_gd != mycpu) 974 lwkt_send_ipiq(td->td_gd, signotify_remote, p); 975 else if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 976 lwkt_schedule(td); 977 } 978 #else 979 if (p == lwkt_preempted_proc()) { 980 signotify(); 981 } else if (p->p_stat == SRUN) { 982 struct thread *td = p->p_thread; 983 984 KASSERT(td != NULL, 985 ("pid %d NULL p_thread stat %d flags %08x", 986 p->p_pid, p->p_stat, p->p_flag)); 987 988 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 989 lwkt_schedule(td); 990 } 991 #endif 992 goto out; 993 } 994 /*NOTREACHED*/ 995 run: 996 setrunnable(p); 997 out: 998 splx(s); 999 } 1000 1001 #ifdef SMP 1002 1003 /* 1004 * This function is called via an IPI. We will be in a critical section but 1005 * the MP lock will NOT be held. Also note that by the time the ipi message 1006 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1007 */ 1008 static void 1009 signotify_remote(void *arg) 1010 { 1011 struct proc *p = arg; 1012 1013 if (p == lwkt_preempted_proc()) { 1014 signotify(); 1015 } else { 1016 struct thread *td = p->p_thread; 1017 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1018 lwkt_schedule(td); 1019 } 1020 } 1021 1022 #endif 1023 1024 static int 1025 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1026 { 1027 sigset_t savedmask, set; 1028 struct proc *p = curproc; 1029 int error, sig, hz, timevalid = 0; 1030 struct timespec rts, ets, ts; 1031 struct timeval tv; 1032 1033 error = 0; 1034 sig = 0; 1035 SIG_CANTMASK(waitset); 1036 savedmask = p->p_sigmask; 1037 1038 if (timeout) { 1039 if (timeout->tv_sec < 0 || 1040 (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000)) { 1041 timevalid = 1; 1042 getnanouptime(&rts); 1043 ets = rts; 1044 timespecadd(&ets, timeout); 1045 } 1046 } 1047 1048 for (;;) { 1049 set = p->p_siglist; 1050 SIGSETAND(set, waitset); 1051 if ((sig = sig_ffs(&set)) != 0) { 1052 SIGFILLSET(p->p_sigmask); 1053 SIGDELSET(p->p_sigmask, sig); 1054 sig = issignal(p); 1055 /* 1056 * It may be a STOP signal, in the case, issignal 1057 * returns 0, because we may stop there, and new 1058 * signal can come in, we should restart if we got 1059 * nothing. 1060 */ 1061 if (sig == 0) 1062 continue; 1063 else 1064 break; 1065 } 1066 1067 /* 1068 * Previous checking got nothing, and we retried but still 1069 * got nothing, we should return the error status. 1070 */ 1071 if (error) 1072 break; 1073 1074 /* 1075 * POSIX says this must be checked after looking for pending 1076 * signals. 1077 */ 1078 if (timeout) { 1079 if (!timevalid) { 1080 error = EINVAL; 1081 break; 1082 } 1083 getnanouptime(&rts); 1084 if (timespeccmp(&rts, &ets, >=)) { 1085 error = EAGAIN; 1086 break; 1087 } 1088 ts = ets; 1089 timespecsub(&ts, &rts); 1090 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1091 hz = tvtohz_high(&tv); 1092 } else 1093 hz = 0; 1094 1095 p->p_sigmask = savedmask; 1096 SIGSETNAND(p->p_sigmask, waitset); 1097 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1098 if (timeout) { 1099 if (error == ERESTART) { 1100 /* can not restart a timeout wait. */ 1101 error = EINTR; 1102 } else if (error == EAGAIN) { 1103 /* will calculate timeout by ourself. */ 1104 error = 0; 1105 } 1106 } 1107 /* Retry ... */ 1108 } 1109 1110 p->p_sigmask = savedmask; 1111 if (sig) { 1112 error = 0; 1113 bzero(info, sizeof(*info)); 1114 info->si_signo = sig; 1115 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1116 } 1117 return (error); 1118 } 1119 1120 int 1121 sigtimedwait(struct sigtimedwait_args *uap) 1122 { 1123 struct timespec ts; 1124 struct timespec *timeout; 1125 sigset_t set; 1126 siginfo_t info; 1127 int error; 1128 1129 if (uap->timeout) { 1130 error = copyin(uap->timeout, &ts, sizeof(ts)); 1131 if (error) 1132 return (error); 1133 timeout = &ts; 1134 } else { 1135 timeout = NULL; 1136 } 1137 error = copyin(uap->set, &set, sizeof(set)); 1138 if (error) 1139 return (error); 1140 error = kern_sigtimedwait(set, &info, timeout); 1141 if (error) 1142 return (error); 1143 if (uap->info) 1144 error = copyout(&info, uap->info, sizeof(info)); 1145 /* Repost if we got an error. */ 1146 if (error) 1147 psignal(curproc, info.si_signo); 1148 else 1149 uap->sysmsg_result = info.si_signo; 1150 return (error); 1151 } 1152 1153 int 1154 sigwaitinfo(struct sigwaitinfo_args *uap) 1155 { 1156 siginfo_t info; 1157 sigset_t set; 1158 int error; 1159 1160 error = copyin(uap->set, &set, sizeof(set)); 1161 if (error) 1162 return (error); 1163 error = kern_sigtimedwait(set, &info, NULL); 1164 if (error) 1165 return (error); 1166 if (uap->info) 1167 error = copyout(&info, uap->info, sizeof(info)); 1168 /* Repost if we got an error. */ 1169 if (error) 1170 psignal(curproc, info.si_signo); 1171 else 1172 uap->sysmsg_result = info.si_signo; 1173 return (error); 1174 } 1175 1176 /* 1177 * If the current process has received a signal that would interrupt a 1178 * system call, return EINTR or ERESTART as appropriate. 1179 */ 1180 int 1181 iscaught(struct proc *p) 1182 { 1183 int sig; 1184 1185 if (p) { 1186 if ((sig = CURSIG(p)) != 0) { 1187 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1188 return (EINTR); 1189 return (ERESTART); 1190 } 1191 } 1192 return(EWOULDBLOCK); 1193 } 1194 1195 /* 1196 * If the current process has received a signal (should be caught or cause 1197 * termination, should interrupt current syscall), return the signal number. 1198 * Stop signals with default action are processed immediately, then cleared; 1199 * they aren't returned. This is checked after each entry to the system for 1200 * a syscall or trap (though this can usually be done without calling issignal 1201 * by checking the pending signal masks in the CURSIG macro.) The normal call 1202 * sequence is 1203 * 1204 * while (sig = CURSIG(curproc)) 1205 * postsig(sig); 1206 */ 1207 int 1208 issignal(struct proc *p) 1209 { 1210 sigset_t mask; 1211 int sig, prop; 1212 1213 for (;;) { 1214 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1215 1216 mask = p->p_siglist; 1217 SIGSETNAND(mask, p->p_sigmask); 1218 if (p->p_flag & P_PPWAIT) 1219 SIG_STOPSIGMASK(mask); 1220 if (!SIGNOTEMPTY(mask)) /* no signal to send */ 1221 return (0); 1222 sig = sig_ffs(&mask); 1223 1224 STOPEVENT(p, S_SIG, sig); 1225 1226 /* 1227 * We should see pending but ignored signals 1228 * only if P_TRACED was on when they were posted. 1229 */ 1230 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1231 SIGDELSET(p->p_siglist, sig); 1232 continue; 1233 } 1234 if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { 1235 /* 1236 * If traced, always stop, and stay 1237 * stopped until released by the parent. 1238 */ 1239 p->p_xstat = sig; 1240 psignal(p->p_pptr, SIGCHLD); 1241 do { 1242 stop(p); 1243 mi_switch(p); 1244 } while (!trace_req(p) && p->p_flag & P_TRACED); 1245 1246 /* 1247 * If parent wants us to take the signal, 1248 * then it will leave it in p->p_xstat; 1249 * otherwise we just look for signals again. 1250 */ 1251 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1252 sig = p->p_xstat; 1253 if (sig == 0) 1254 continue; 1255 1256 /* 1257 * Put the new signal into p_siglist. If the 1258 * signal is being masked, look for other signals. 1259 */ 1260 SIGADDSET(p->p_siglist, sig); 1261 if (SIGISMEMBER(p->p_sigmask, sig)) 1262 continue; 1263 1264 /* 1265 * If the traced bit got turned off, go back up 1266 * to the top to rescan signals. This ensures 1267 * that p_sig* and ps_sigact are consistent. 1268 */ 1269 if ((p->p_flag & P_TRACED) == 0) 1270 continue; 1271 } 1272 1273 prop = sigprop(sig); 1274 1275 /* 1276 * Decide whether the signal should be returned. 1277 * Return the signal's number, or fall through 1278 * to clear it from the pending mask. 1279 */ 1280 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1281 1282 case (int)SIG_DFL: 1283 /* 1284 * Don't take default actions on system processes. 1285 */ 1286 if (p->p_pid <= 1) { 1287 #ifdef DIAGNOSTIC 1288 /* 1289 * Are you sure you want to ignore SIGSEGV 1290 * in init? XXX 1291 */ 1292 printf("Process (pid %lu) got signal %d\n", 1293 (u_long)p->p_pid, sig); 1294 #endif 1295 break; /* == ignore */ 1296 } 1297 1298 /* 1299 * Handle the in-kernel checkpoint action 1300 */ 1301 if (prop & SA_CKPT) { 1302 checkpoint_signal_handler(p); 1303 break; 1304 } 1305 1306 /* 1307 * If there is a pending stop signal to process 1308 * with default action, stop here, 1309 * then clear the signal. However, 1310 * if process is member of an orphaned 1311 * process group, ignore tty stop signals. 1312 */ 1313 if (prop & SA_STOP) { 1314 if (p->p_flag & P_TRACED || 1315 (p->p_pgrp->pg_jobc == 0 && 1316 prop & SA_TTYSTOP)) 1317 break; /* == ignore */ 1318 p->p_xstat = sig; 1319 stop(p); 1320 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1321 psignal(p->p_pptr, SIGCHLD); 1322 mi_switch(p); 1323 break; 1324 } else if (prop & SA_IGNORE) { 1325 /* 1326 * Except for SIGCONT, shouldn't get here. 1327 * Default action is to ignore; drop it. 1328 */ 1329 break; /* == ignore */ 1330 } else { 1331 return (sig); 1332 } 1333 1334 /*NOTREACHED*/ 1335 1336 case (int)SIG_IGN: 1337 /* 1338 * Masking above should prevent us ever trying 1339 * to take action on an ignored signal other 1340 * than SIGCONT, unless process is traced. 1341 */ 1342 if ((prop & SA_CONT) == 0 && 1343 (p->p_flag & P_TRACED) == 0) 1344 printf("issignal\n"); 1345 break; /* == ignore */ 1346 1347 default: 1348 /* 1349 * This signal has an action, let 1350 * postsig() process it. 1351 */ 1352 return (sig); 1353 } 1354 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1355 } 1356 /* NOTREACHED */ 1357 } 1358 1359 /* 1360 * Put the argument process into the stopped state and notify the parent 1361 * via wakeup. Signals are handled elsewhere. The process must not be 1362 * on the run queue. 1363 */ 1364 void 1365 stop(struct proc *p) 1366 { 1367 p->p_stat = SSTOP; 1368 p->p_flag &= ~P_WAITED; 1369 wakeup((caddr_t)p->p_pptr); 1370 } 1371 1372 /* 1373 * Take the action for the specified signal 1374 * from the current set of pending signals. 1375 */ 1376 void 1377 postsig(int sig) 1378 { 1379 struct proc *p = curproc; 1380 struct sigacts *ps = p->p_sigacts; 1381 sig_t action; 1382 sigset_t returnmask; 1383 int code; 1384 1385 KASSERT(sig != 0, ("postsig")); 1386 1387 SIGDELSET(p->p_siglist, sig); 1388 action = ps->ps_sigact[_SIG_IDX(sig)]; 1389 #ifdef KTRACE 1390 if (KTRPOINT(p->p_thread, KTR_PSIG)) 1391 ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ? 1392 &p->p_oldsigmask : &p->p_sigmask, 0); 1393 #endif 1394 STOPEVENT(p, S_SIG, sig); 1395 1396 if (action == SIG_DFL) { 1397 /* 1398 * Default action, where the default is to kill 1399 * the process. (Other cases were ignored above.) 1400 */ 1401 sigexit(p, sig); 1402 /* NOTREACHED */ 1403 } else { 1404 /* 1405 * If we get here, the signal must be caught. 1406 */ 1407 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), 1408 ("postsig action")); 1409 /* 1410 * Set the new mask value and also defer further 1411 * occurrences of this signal. 1412 * 1413 * Special case: user has done a sigsuspend. Here the 1414 * current mask is not of interest, but rather the 1415 * mask from before the sigsuspend is what we want 1416 * restored after the signal processing is completed. 1417 */ 1418 splhigh(); 1419 if (p->p_flag & P_OLDMASK) { 1420 returnmask = p->p_oldsigmask; 1421 p->p_flag &= ~P_OLDMASK; 1422 } else { 1423 returnmask = p->p_sigmask; 1424 } 1425 1426 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1427 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1428 SIGADDSET(p->p_sigmask, sig); 1429 1430 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1431 /* 1432 * See kern_sigaction() for origin of this code. 1433 */ 1434 SIGDELSET(p->p_sigcatch, sig); 1435 if (sig != SIGCONT && 1436 sigprop(sig) & SA_IGNORE) 1437 SIGADDSET(p->p_sigignore, sig); 1438 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1439 } 1440 spl0(); 1441 p->p_stats->p_ru.ru_nsignals++; 1442 if (p->p_sig != sig) { 1443 code = 0; 1444 } else { 1445 code = p->p_code; 1446 p->p_code = 0; 1447 p->p_sig = 0; 1448 } 1449 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1450 } 1451 } 1452 1453 /* 1454 * Kill the current process for stated reason. 1455 */ 1456 void 1457 killproc(struct proc *p, char *why) 1458 { 1459 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, 1460 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1461 psignal(p, SIGKILL); 1462 } 1463 1464 /* 1465 * Force the current process to exit with the specified signal, dumping core 1466 * if appropriate. We bypass the normal tests for masked and caught signals, 1467 * allowing unrecoverable failures to terminate the process without changing 1468 * signal state. Mark the accounting record with the signal termination. 1469 * If dumping core, save the signal number for the debugger. Calls exit and 1470 * does not return. 1471 */ 1472 void 1473 sigexit(struct proc *p, int sig) 1474 { 1475 p->p_acflag |= AXSIG; 1476 if (sigprop(sig) & SA_CORE) { 1477 p->p_sig = sig; 1478 /* 1479 * Log signals which would cause core dumps 1480 * (Log as LOG_INFO to appease those who don't want 1481 * these messages.) 1482 * XXX : Todo, as well as euid, write out ruid too 1483 */ 1484 if (coredump(p) == 0) 1485 sig |= WCOREFLAG; 1486 if (kern_logsigexit) 1487 log(LOG_INFO, 1488 "pid %d (%s), uid %d: exited on signal %d%s\n", 1489 p->p_pid, p->p_comm, 1490 p->p_ucred ? p->p_ucred->cr_uid : -1, 1491 sig &~ WCOREFLAG, 1492 sig & WCOREFLAG ? " (core dumped)" : ""); 1493 } 1494 exit1(W_EXITCODE(0, sig)); 1495 /* NOTREACHED */ 1496 } 1497 1498 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1499 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1500 sizeof(corefilename), "process corefile name format string"); 1501 1502 /* 1503 * expand_name(name, uid, pid) 1504 * Expand the name described in corefilename, using name, uid, and pid. 1505 * corefilename is a printf-like string, with three format specifiers: 1506 * %N name of process ("name") 1507 * %P process id (pid) 1508 * %U user id (uid) 1509 * For example, "%N.core" is the default; they can be disabled completely 1510 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1511 * This is controlled by the sysctl variable kern.corefile (see above). 1512 */ 1513 1514 static char * 1515 expand_name(const char *name, uid_t uid, pid_t pid) 1516 { 1517 char *temp; 1518 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1519 int i, n; 1520 char *format = corefilename; 1521 size_t namelen; 1522 1523 temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1524 if (temp == NULL) 1525 return NULL; 1526 namelen = strlen(name); 1527 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1528 int l; 1529 switch (format[i]) { 1530 case '%': /* Format character */ 1531 i++; 1532 switch (format[i]) { 1533 case '%': 1534 temp[n++] = '%'; 1535 break; 1536 case 'N': /* process name */ 1537 if ((n + namelen) > MAXPATHLEN) { 1538 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1539 pid, name, uid, temp, name); 1540 free(temp, M_TEMP); 1541 return NULL; 1542 } 1543 memcpy(temp+n, name, namelen); 1544 n += namelen; 1545 break; 1546 case 'P': /* process id */ 1547 l = sprintf(buf, "%u", pid); 1548 if ((n + l) > MAXPATHLEN) { 1549 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1550 pid, name, uid, temp, name); 1551 free(temp, M_TEMP); 1552 return NULL; 1553 } 1554 memcpy(temp+n, buf, l); 1555 n += l; 1556 break; 1557 case 'U': /* user id */ 1558 l = sprintf(buf, "%u", uid); 1559 if ((n + l) > MAXPATHLEN) { 1560 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1561 pid, name, uid, temp, name); 1562 free(temp, M_TEMP); 1563 return NULL; 1564 } 1565 memcpy(temp+n, buf, l); 1566 n += l; 1567 break; 1568 default: 1569 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1570 } 1571 break; 1572 default: 1573 temp[n++] = format[i]; 1574 } 1575 } 1576 temp[n] = '\0'; 1577 return temp; 1578 } 1579 1580 /* 1581 * Dump a process' core. The main routine does some 1582 * policy checking, and creates the name of the coredump; 1583 * then it passes on a vnode and a size limit to the process-specific 1584 * coredump routine if there is one; if there _is not_ one, it returns 1585 * ENOSYS; otherwise it returns the error from the process-specific routine. 1586 */ 1587 1588 static int 1589 coredump(struct proc *p) 1590 { 1591 struct vnode *vp; 1592 struct ucred *cred = p->p_ucred; 1593 struct thread *td = p->p_thread; 1594 struct flock lf; 1595 struct nlookupdata nd; 1596 struct vattr vattr; 1597 int error, error1; 1598 char *name; /* name of corefile */ 1599 off_t limit; 1600 1601 STOPEVENT(p, S_CORE, 0); 1602 1603 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1604 return (EFAULT); 1605 1606 /* 1607 * Note that the bulk of limit checking is done after 1608 * the corefile is created. The exception is if the limit 1609 * for corefiles is 0, in which case we don't bother 1610 * creating the corefile at all. This layout means that 1611 * a corefile is truncated instead of not being created, 1612 * if it is larger than the limit. 1613 */ 1614 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1615 if (limit == 0) 1616 return EFBIG; 1617 1618 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1619 if (name == NULL) 1620 return (EINVAL); 1621 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1622 if (error == 0) 1623 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1624 free(name, M_TEMP); 1625 if (error) { 1626 nlookup_done(&nd); 1627 return (error); 1628 } 1629 vp = nd.nl_open_vp; 1630 nd.nl_open_vp = NULL; 1631 nlookup_done(&nd); 1632 1633 VOP_UNLOCK(vp, 0, td); 1634 lf.l_whence = SEEK_SET; 1635 lf.l_start = 0; 1636 lf.l_len = 0; 1637 lf.l_type = F_WRLCK; 1638 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK); 1639 if (error) 1640 goto out2; 1641 1642 /* Don't dump to non-regular files or files with links. */ 1643 if (vp->v_type != VREG || 1644 VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) { 1645 error = EFAULT; 1646 goto out1; 1647 } 1648 1649 VATTR_NULL(&vattr); 1650 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1651 vattr.va_size = 0; 1652 VOP_LEASE(vp, td, cred, LEASE_WRITE); 1653 VOP_SETATTR(vp, &vattr, cred, td); 1654 p->p_acflag |= ACORE; 1655 VOP_UNLOCK(vp, 0, td); 1656 1657 error = p->p_sysent->sv_coredump ? 1658 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1659 1660 out1: 1661 lf.l_type = F_UNLCK; 1662 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 1663 out2: 1664 error1 = vn_close(vp, FWRITE, td); 1665 if (error == 0) 1666 error = error1; 1667 return (error); 1668 } 1669 1670 /* 1671 * Nonexistent system call-- signal process (may want to handle it). 1672 * Flag error in case process won't see signal immediately (blocked or ignored). 1673 */ 1674 /* ARGSUSED */ 1675 int 1676 nosys(struct nosys_args *args) 1677 { 1678 psignal(curproc, SIGSYS); 1679 return (EINVAL); 1680 } 1681 1682 /* 1683 * Send a SIGIO or SIGURG signal to a process or process group using 1684 * stored credentials rather than those of the current process. 1685 */ 1686 void 1687 pgsigio(struct sigio *sigio, int sig, int checkctty) 1688 { 1689 if (sigio == NULL) 1690 return; 1691 1692 if (sigio->sio_pgid > 0) { 1693 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1694 sigio->sio_proc)) 1695 psignal(sigio->sio_proc, sig); 1696 } else if (sigio->sio_pgid < 0) { 1697 struct proc *p; 1698 1699 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) 1700 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1701 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1702 psignal(p, sig); 1703 } 1704 } 1705 1706 static int 1707 filt_sigattach(struct knote *kn) 1708 { 1709 struct proc *p = curproc; 1710 1711 kn->kn_ptr.p_proc = p; 1712 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1713 1714 /* XXX lock the proc here while adding to the list? */ 1715 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1716 1717 return (0); 1718 } 1719 1720 static void 1721 filt_sigdetach(struct knote *kn) 1722 { 1723 struct proc *p = kn->kn_ptr.p_proc; 1724 1725 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1726 } 1727 1728 /* 1729 * signal knotes are shared with proc knotes, so we apply a mask to 1730 * the hint in order to differentiate them from process hints. This 1731 * could be avoided by using a signal-specific knote list, but probably 1732 * isn't worth the trouble. 1733 */ 1734 static int 1735 filt_signal(struct knote *kn, long hint) 1736 { 1737 if (hint & NOTE_SIGNAL) { 1738 hint &= ~NOTE_SIGNAL; 1739 1740 if (kn->kn_id == hint) 1741 kn->kn_data++; 1742 } 1743 return (kn->kn_data != 0); 1744 } 1745