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 1.38 2005/10/11 09:59:56 corecode 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 #include <sys/thread2.h> 69 70 71 #include <machine/ipl.h> 72 #include <machine/cpu.h> 73 #include <machine/smp.h> 74 75 static int coredump(struct proc *); 76 static char *expand_name(const char *, uid_t, pid_t); 77 static int killpg(int sig, int pgid, int all); 78 static int sig_ffs(sigset_t *set); 79 static int sigprop(int sig); 80 static void stop(struct proc *); 81 #ifdef SMP 82 static void signotify_remote(void *arg); 83 #endif 84 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 85 struct timespec *timeout); 86 87 static int filt_sigattach(struct knote *kn); 88 static void filt_sigdetach(struct knote *kn); 89 static int filt_signal(struct knote *kn, long hint); 90 91 struct filterops sig_filtops = 92 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 93 94 static int kern_logsigexit = 1; 95 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 96 &kern_logsigexit, 0, 97 "Log processes quitting on abnormal signals to syslog(3)"); 98 99 /* 100 * Can process p, with pcred pc, send the signal sig to process q? 101 */ 102 #define CANSIGNAL(q, sig) \ 103 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 105 106 /* 107 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 108 */ 109 #define CANSIGIO(ruid, uc, q) \ 110 ((uc)->cr_uid == 0 || \ 111 (ruid) == (q)->p_ucred->cr_ruid || \ 112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 113 (ruid) == (q)->p_ucred->cr_uid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_uid) 115 116 int sugid_coredump; 117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 119 120 static int do_coredump = 1; 121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 122 &do_coredump, 0, "Enable/Disable coredumps"); 123 124 /* 125 * Signal properties and actions. 126 * The array below categorizes the signals and their default actions 127 * according to the following properties: 128 */ 129 #define SA_KILL 0x01 /* terminates process by default */ 130 #define SA_CORE 0x02 /* ditto and coredumps */ 131 #define SA_STOP 0x04 /* suspend process */ 132 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 133 #define SA_IGNORE 0x10 /* ignore by default */ 134 #define SA_CONT 0x20 /* continue if suspended */ 135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 136 #define SA_CKPT 0x80 /* checkpoint process */ 137 138 139 static int sigproptbl[NSIG] = { 140 SA_KILL, /* SIGHUP */ 141 SA_KILL, /* SIGINT */ 142 SA_KILL|SA_CORE, /* SIGQUIT */ 143 SA_KILL|SA_CORE, /* SIGILL */ 144 SA_KILL|SA_CORE, /* SIGTRAP */ 145 SA_KILL|SA_CORE, /* SIGABRT */ 146 SA_KILL|SA_CORE, /* SIGEMT */ 147 SA_KILL|SA_CORE, /* SIGFPE */ 148 SA_KILL, /* SIGKILL */ 149 SA_KILL|SA_CORE, /* SIGBUS */ 150 SA_KILL|SA_CORE, /* SIGSEGV */ 151 SA_KILL|SA_CORE, /* SIGSYS */ 152 SA_KILL, /* SIGPIPE */ 153 SA_KILL, /* SIGALRM */ 154 SA_KILL, /* SIGTERM */ 155 SA_IGNORE, /* SIGURG */ 156 SA_STOP, /* SIGSTOP */ 157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 158 SA_IGNORE|SA_CONT, /* SIGCONT */ 159 SA_IGNORE, /* SIGCHLD */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 162 SA_IGNORE, /* SIGIO */ 163 SA_KILL, /* SIGXCPU */ 164 SA_KILL, /* SIGXFSZ */ 165 SA_KILL, /* SIGVTALRM */ 166 SA_KILL, /* SIGPROF */ 167 SA_IGNORE, /* SIGWINCH */ 168 SA_IGNORE, /* SIGINFO */ 169 SA_KILL, /* SIGUSR1 */ 170 SA_KILL, /* SIGUSR2 */ 171 SA_IGNORE, /* SIGTHR */ 172 SA_CKPT, /* SIGCKPT */ 173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 204 205 }; 206 207 static __inline int 208 sigprop(int sig) 209 { 210 211 if (sig > 0 && sig < NSIG) 212 return (sigproptbl[_SIG_IDX(sig)]); 213 return (0); 214 } 215 216 static __inline int 217 sig_ffs(sigset_t *set) 218 { 219 int i; 220 221 for (i = 0; i < _SIG_WORDS; i++) 222 if (set->__bits[i]) 223 return (ffs(set->__bits[i]) + (i * 32)); 224 return (0); 225 } 226 227 int 228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 229 { 230 struct thread *td = curthread; 231 struct proc *p = td->td_proc; 232 struct sigacts *ps = p->p_sigacts; 233 234 if (sig <= 0 || sig > _SIG_MAXSIG) 235 return (EINVAL); 236 237 if (oact) { 238 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 239 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 240 oact->sa_flags = 0; 241 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 242 oact->sa_flags |= SA_ONSTACK; 243 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 244 oact->sa_flags |= SA_RESTART; 245 if (SIGISMEMBER(ps->ps_sigreset, sig)) 246 oact->sa_flags |= SA_RESETHAND; 247 if (SIGISMEMBER(ps->ps_signodefer, sig)) 248 oact->sa_flags |= SA_NODEFER; 249 if (SIGISMEMBER(ps->ps_siginfo, sig)) 250 oact->sa_flags |= SA_SIGINFO; 251 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) 252 oact->sa_flags |= SA_NOCLDSTOP; 253 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) 254 oact->sa_flags |= SA_NOCLDWAIT; 255 } 256 if (act) { 257 if ((sig == SIGKILL || sig == SIGSTOP) && 258 act->sa_handler != SIG_DFL) 259 return (EINVAL); 260 261 /* 262 * Change setting atomically. 263 */ 264 crit_enter(); 265 266 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 267 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 268 if (act->sa_flags & SA_SIGINFO) { 269 ps->ps_sigact[_SIG_IDX(sig)] = 270 (__sighandler_t *)act->sa_sigaction; 271 SIGADDSET(ps->ps_siginfo, sig); 272 } else { 273 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 274 SIGDELSET(ps->ps_siginfo, sig); 275 } 276 if (!(act->sa_flags & SA_RESTART)) 277 SIGADDSET(ps->ps_sigintr, sig); 278 else 279 SIGDELSET(ps->ps_sigintr, sig); 280 if (act->sa_flags & SA_ONSTACK) 281 SIGADDSET(ps->ps_sigonstack, sig); 282 else 283 SIGDELSET(ps->ps_sigonstack, sig); 284 if (act->sa_flags & SA_RESETHAND) 285 SIGADDSET(ps->ps_sigreset, sig); 286 else 287 SIGDELSET(ps->ps_sigreset, sig); 288 if (act->sa_flags & SA_NODEFER) 289 SIGADDSET(ps->ps_signodefer, sig); 290 else 291 SIGDELSET(ps->ps_signodefer, sig); 292 if (sig == SIGCHLD) { 293 if (act->sa_flags & SA_NOCLDSTOP) 294 p->p_procsig->ps_flag |= PS_NOCLDSTOP; 295 else 296 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; 297 if (act->sa_flags & SA_NOCLDWAIT) { 298 /* 299 * Paranoia: since SA_NOCLDWAIT is implemented 300 * by reparenting the dying child to PID 1 (and 301 * trust it to reap the zombie), PID 1 itself 302 * is forbidden to set SA_NOCLDWAIT. 303 */ 304 if (p->p_pid == 1) 305 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 306 else 307 p->p_procsig->ps_flag |= PS_NOCLDWAIT; 308 } else { 309 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 310 } 311 } 312 /* 313 * Set bit in p_sigignore for signals that are set to SIG_IGN, 314 * and for signals set to SIG_DFL where the default is to 315 * ignore. However, don't put SIGCONT in p_sigignore, as we 316 * have to restart the process. 317 */ 318 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 319 (sigprop(sig) & SA_IGNORE && 320 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 321 /* never to be seen again */ 322 SIGDELSET(p->p_siglist, sig); 323 if (sig != SIGCONT) 324 /* easier in psignal */ 325 SIGADDSET(p->p_sigignore, sig); 326 SIGDELSET(p->p_sigcatch, sig); 327 } else { 328 SIGDELSET(p->p_sigignore, sig); 329 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 330 SIGDELSET(p->p_sigcatch, sig); 331 else 332 SIGADDSET(p->p_sigcatch, sig); 333 } 334 335 crit_exit(); 336 } 337 return (0); 338 } 339 340 int 341 sigaction(struct sigaction_args *uap) 342 { 343 struct sigaction act, oact; 344 struct sigaction *actp, *oactp; 345 int error; 346 347 actp = (uap->act != NULL) ? &act : NULL; 348 oactp = (uap->oact != NULL) ? &oact : NULL; 349 if (actp) { 350 error = copyin(uap->act, actp, sizeof(act)); 351 if (error) 352 return (error); 353 } 354 error = kern_sigaction(uap->sig, actp, oactp); 355 if (oactp && !error) { 356 error = copyout(oactp, uap->oact, sizeof(oact)); 357 } 358 return (error); 359 } 360 361 /* 362 * Initialize signal state for process 0; 363 * set to ignore signals that are ignored by default. 364 */ 365 void 366 siginit(struct proc *p) 367 { 368 int i; 369 370 for (i = 1; i <= NSIG; i++) 371 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 372 SIGADDSET(p->p_sigignore, i); 373 } 374 375 /* 376 * Reset signals for an exec of the specified process. 377 */ 378 void 379 execsigs(struct proc *p) 380 { 381 struct sigacts *ps = p->p_sigacts; 382 int sig; 383 384 /* 385 * Reset caught signals. Held signals remain held 386 * through p_sigmask (unless they were caught, 387 * and are now ignored by default). 388 */ 389 while (SIGNOTEMPTY(p->p_sigcatch)) { 390 sig = sig_ffs(&p->p_sigcatch); 391 SIGDELSET(p->p_sigcatch, sig); 392 if (sigprop(sig) & SA_IGNORE) { 393 if (sig != SIGCONT) 394 SIGADDSET(p->p_sigignore, sig); 395 SIGDELSET(p->p_siglist, sig); 396 } 397 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 398 } 399 /* 400 * Reset stack state to the user stack. 401 * Clear set of signals caught on the signal stack. 402 */ 403 p->p_sigstk.ss_flags = SS_DISABLE; 404 p->p_sigstk.ss_size = 0; 405 p->p_sigstk.ss_sp = 0; 406 p->p_flag &= ~P_ALTSTACK; 407 /* 408 * Reset no zombies if child dies flag as Solaris does. 409 */ 410 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 411 } 412 413 /* 414 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 415 * 416 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 417 * p == curproc. 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 struct lwp *lp = &p->p_lwp; 773 int prop; 774 sig_t action; 775 776 if (sig > _SIG_MAXSIG || sig <= 0) { 777 printf("psignal: signal %d\n", sig); 778 panic("psignal signal number"); 779 } 780 781 crit_enter(); 782 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 783 crit_exit(); 784 785 prop = sigprop(sig); 786 787 /* 788 * If proc is traced, always give parent a chance; 789 * if signal event is tracked by procfs, give *that* 790 * a chance, as well. 791 */ 792 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 793 action = SIG_DFL; 794 } else { 795 /* 796 * If the signal is being ignored, 797 * then we forget about it immediately. 798 * (Note: we don't set SIGCONT in p_sigignore, 799 * and if it is set to SIG_IGN, 800 * action will be SIG_DFL here.) 801 */ 802 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 803 return; 804 if (SIGISMEMBER(p->p_sigmask, sig)) 805 action = SIG_HOLD; 806 else if (SIGISMEMBER(p->p_sigcatch, sig)) 807 action = SIG_CATCH; 808 else 809 action = SIG_DFL; 810 } 811 812 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 813 (p->p_flag & P_TRACED) == 0) { 814 p->p_nice = NZERO; 815 } 816 817 if (prop & SA_CONT) 818 SIG_STOPSIGMASK(p->p_siglist); 819 820 821 if (prop & SA_STOP) { 822 /* 823 * If sending a tty stop signal to a member of an orphaned 824 * process group, discard the signal here if the action 825 * is default; don't stop the process below if sleeping, 826 * and don't clear any pending SIGCONT. 827 */ 828 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 829 action == SIG_DFL) { 830 return; 831 } 832 SIG_CONTSIGMASK(p->p_siglist); 833 } 834 SIGADDSET(p->p_siglist, sig); 835 836 /* 837 * Defer further processing for signals which are held, 838 * except that stopped processes must be continued by SIGCONT. 839 */ 840 if (action == SIG_HOLD && (!(prop & SA_CONT) || p->p_stat != SSTOP)) 841 return; 842 843 crit_enter(); 844 845 switch (p->p_stat) { 846 case SSLEEP: 847 /* 848 * If process is sleeping uninterruptibly 849 * we can't interrupt the sleep... the signal will 850 * be noticed when the process returns through 851 * trap() or syscall(). 852 */ 853 if ((p->p_flag & P_SINTR) == 0) 854 goto out; 855 /* 856 * Process is sleeping and traced... make it runnable 857 * so it can discover the signal in issignal() and stop 858 * for the parent. 859 */ 860 if (p->p_flag & P_TRACED) 861 goto run; 862 /* 863 * If SIGCONT is default (or ignored) and process is 864 * asleep, we are finished; the process should not 865 * be awakened. 866 */ 867 if ((prop & SA_CONT) && action == SIG_DFL) { 868 SIGDELSET(p->p_siglist, sig); 869 goto out; 870 } 871 /* 872 * When a sleeping process receives a stop 873 * signal, process immediately if possible. 874 * All other (caught or default) signals 875 * cause the process to run. 876 */ 877 if (prop & SA_STOP) { 878 if (action != SIG_DFL) 879 goto run; 880 /* 881 * If a child holding parent blocked, 882 * stopping could cause deadlock. 883 */ 884 if (p->p_flag & P_PPWAIT) 885 goto out; 886 SIGDELSET(p->p_siglist, sig); 887 p->p_xstat = sig; 888 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 889 psignal(p->p_pptr, SIGCHLD); 890 stop(p); 891 goto out; 892 } else { 893 goto run; 894 } 895 /*NOTREACHED*/ 896 case SSTOP: 897 /* 898 * If traced process is already stopped, 899 * then no further action is necessary. 900 */ 901 if (p->p_flag & P_TRACED) 902 goto out; 903 904 /* 905 * Kill signal always sets processes running. 906 */ 907 if (sig == SIGKILL) 908 goto run; 909 910 if (prop & SA_CONT) { 911 /* 912 * If SIGCONT is default (or ignored), we continue the 913 * process but don't leave the signal in p_siglist, as 914 * it has no further action. If SIGCONT is held, we 915 * continue the process and leave the signal in 916 * p_siglist. If the process catches SIGCONT, let it 917 * handle the signal itself. If it isn't waiting on 918 * an event, then it goes back to run state. 919 * Otherwise, process goes back to sleep state. 920 */ 921 if (action == SIG_DFL) 922 SIGDELSET(p->p_siglist, sig); 923 if (action == SIG_CATCH) 924 goto run; 925 if (p->p_wchan == 0) 926 goto run; 927 clrrunnable(p, SSLEEP); 928 goto out; 929 } 930 931 if (prop & SA_STOP) { 932 /* 933 * Already stopped, don't need to stop again. 934 * (If we did the shell could get confused.) 935 */ 936 SIGDELSET(p->p_siglist, sig); 937 goto out; 938 } 939 940 /* 941 * If process is sleeping interruptibly, then simulate a 942 * wakeup so that when it is continued, it will be made 943 * runnable and can look at the signal. But don't make 944 * the process runnable, leave it stopped. 945 */ 946 if (p->p_wchan && (p->p_flag & P_SINTR)) 947 unsleep(p->p_thread); 948 goto out; 949 default: 950 /* 951 * SRUN, SIDL, SZOMB do nothing with the signal, 952 * other than kicking ourselves if we are running. 953 * It will either never be noticed, or noticed very soon. 954 * 955 * Note that p_thread may be NULL or may not be completely 956 * initialized if the process is in the SIDL or SZOMB state. 957 * 958 * For SMP we may have to forward the request to another cpu. 959 * YYY the MP lock prevents the target process from moving 960 * to another cpu, see kern/kern_switch.c 961 * 962 * If the target thread is waiting on its message port, 963 * wakeup the target thread so it can check (or ignore) 964 * the new signal. YYY needs cleanup. 965 */ 966 #ifdef SMP 967 if (lp == lwkt_preempted_proc()) { 968 signotify(); 969 } else if (p->p_stat == SRUN) { 970 struct thread *td = p->p_thread; 971 972 KASSERT(td != NULL, 973 ("pid %d NULL p_thread stat %d flags %08x", 974 p->p_pid, p->p_stat, p->p_flag)); 975 976 if (td->td_gd != mycpu) 977 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 978 else if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 979 lwkt_schedule(td); 980 } 981 #else 982 if (lp == lwkt_preempted_proc()) { 983 signotify(); 984 } else if (p->p_stat == SRUN) { 985 struct thread *td = p->p_thread; 986 987 KASSERT(td != NULL, 988 ("pid %d NULL p_thread stat %d flags %08x", 989 p->p_pid, p->p_stat, p->p_flag)); 990 991 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 992 lwkt_schedule(td); 993 } 994 #endif 995 goto out; 996 } 997 /*NOTREACHED*/ 998 run: 999 setrunnable(p); 1000 out: 1001 crit_exit(); 1002 } 1003 1004 #ifdef SMP 1005 1006 /* 1007 * This function is called via an IPI. We will be in a critical section but 1008 * the MP lock will NOT be held. Also note that by the time the ipi message 1009 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1010 */ 1011 static void 1012 signotify_remote(void *arg) 1013 { 1014 struct lwp *lp = arg; 1015 1016 if (lp == lwkt_preempted_proc()) { 1017 signotify(); 1018 } else { 1019 struct thread *td = lp->lwp_thread; 1020 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1021 lwkt_schedule(td); 1022 } 1023 } 1024 1025 #endif 1026 1027 static int 1028 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1029 { 1030 sigset_t savedmask, set; 1031 struct proc *p = curproc; 1032 int error, sig, hz, timevalid = 0; 1033 struct timespec rts, ets, ts; 1034 struct timeval tv; 1035 1036 error = 0; 1037 sig = 0; 1038 SIG_CANTMASK(waitset); 1039 savedmask = p->p_sigmask; 1040 1041 if (timeout) { 1042 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1043 timeout->tv_nsec < 1000000000) { 1044 timevalid = 1; 1045 getnanouptime(&rts); 1046 ets = rts; 1047 timespecadd(&ets, timeout); 1048 } 1049 } 1050 1051 for (;;) { 1052 set = p->p_siglist; 1053 SIGSETAND(set, waitset); 1054 if ((sig = sig_ffs(&set)) != 0) { 1055 SIGFILLSET(p->p_sigmask); 1056 SIGDELSET(p->p_sigmask, sig); 1057 SIG_CANTMASK(p->p_sigmask); 1058 sig = issignal(p); 1059 /* 1060 * It may be a STOP signal, in the case, issignal 1061 * returns 0, because we may stop there, and new 1062 * signal can come in, we should restart if we got 1063 * nothing. 1064 */ 1065 if (sig == 0) 1066 continue; 1067 else 1068 break; 1069 } 1070 1071 /* 1072 * Previous checking got nothing, and we retried but still 1073 * got nothing, we should return the error status. 1074 */ 1075 if (error) 1076 break; 1077 1078 /* 1079 * POSIX says this must be checked after looking for pending 1080 * signals. 1081 */ 1082 if (timeout) { 1083 if (!timevalid) { 1084 error = EINVAL; 1085 break; 1086 } 1087 getnanouptime(&rts); 1088 if (timespeccmp(&rts, &ets, >=)) { 1089 error = EAGAIN; 1090 break; 1091 } 1092 ts = ets; 1093 timespecsub(&ts, &rts); 1094 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1095 hz = tvtohz_high(&tv); 1096 } else 1097 hz = 0; 1098 1099 p->p_sigmask = savedmask; 1100 SIGSETNAND(p->p_sigmask, waitset); 1101 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1102 if (timeout) { 1103 if (error == ERESTART) { 1104 /* can not restart a timeout wait. */ 1105 error = EINTR; 1106 } else if (error == EAGAIN) { 1107 /* will calculate timeout by ourself. */ 1108 error = 0; 1109 } 1110 } 1111 /* Retry ... */ 1112 } 1113 1114 p->p_sigmask = savedmask; 1115 if (sig) { 1116 error = 0; 1117 bzero(info, sizeof(*info)); 1118 info->si_signo = sig; 1119 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1120 } 1121 return (error); 1122 } 1123 1124 int 1125 sigtimedwait(struct sigtimedwait_args *uap) 1126 { 1127 struct timespec ts; 1128 struct timespec *timeout; 1129 sigset_t set; 1130 siginfo_t info; 1131 int error; 1132 1133 if (uap->timeout) { 1134 error = copyin(uap->timeout, &ts, sizeof(ts)); 1135 if (error) 1136 return (error); 1137 timeout = &ts; 1138 } else { 1139 timeout = NULL; 1140 } 1141 error = copyin(uap->set, &set, sizeof(set)); 1142 if (error) 1143 return (error); 1144 error = kern_sigtimedwait(set, &info, timeout); 1145 if (error) 1146 return (error); 1147 if (uap->info) 1148 error = copyout(&info, uap->info, sizeof(info)); 1149 /* Repost if we got an error. */ 1150 if (error) 1151 psignal(curproc, info.si_signo); 1152 else 1153 uap->sysmsg_result = info.si_signo; 1154 return (error); 1155 } 1156 1157 int 1158 sigwaitinfo(struct sigwaitinfo_args *uap) 1159 { 1160 siginfo_t info; 1161 sigset_t set; 1162 int error; 1163 1164 error = copyin(uap->set, &set, sizeof(set)); 1165 if (error) 1166 return (error); 1167 error = kern_sigtimedwait(set, &info, NULL); 1168 if (error) 1169 return (error); 1170 if (uap->info) 1171 error = copyout(&info, uap->info, sizeof(info)); 1172 /* Repost if we got an error. */ 1173 if (error) 1174 psignal(curproc, info.si_signo); 1175 else 1176 uap->sysmsg_result = info.si_signo; 1177 return (error); 1178 } 1179 1180 /* 1181 * If the current process has received a signal that would interrupt a 1182 * system call, return EINTR or ERESTART as appropriate. 1183 */ 1184 int 1185 iscaught(struct proc *p) 1186 { 1187 int sig; 1188 1189 if (p) { 1190 if ((sig = CURSIG(p)) != 0) { 1191 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1192 return (EINTR); 1193 return (ERESTART); 1194 } 1195 } 1196 return(EWOULDBLOCK); 1197 } 1198 1199 /* 1200 * If the current process has received a signal (should be caught or cause 1201 * termination, should interrupt current syscall), return the signal number. 1202 * Stop signals with default action are processed immediately, then cleared; 1203 * they aren't returned. This is checked after each entry to the system for 1204 * a syscall or trap (though this can usually be done without calling issignal 1205 * by checking the pending signal masks in the CURSIG macro.) The normal call 1206 * sequence is 1207 * 1208 * while (sig = CURSIG(curproc)) 1209 * postsig(sig); 1210 */ 1211 int 1212 issignal(struct proc *p) 1213 { 1214 sigset_t mask; 1215 int sig, prop; 1216 1217 for (;;) { 1218 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1219 1220 mask = p->p_siglist; 1221 SIGSETNAND(mask, p->p_sigmask); 1222 if (p->p_flag & P_PPWAIT) 1223 SIG_STOPSIGMASK(mask); 1224 if (!SIGNOTEMPTY(mask)) /* no signal to send */ 1225 return (0); 1226 sig = sig_ffs(&mask); 1227 1228 STOPEVENT(p, S_SIG, sig); 1229 1230 /* 1231 * We should see pending but ignored signals 1232 * only if P_TRACED was on when they were posted. 1233 */ 1234 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1235 SIGDELSET(p->p_siglist, sig); 1236 continue; 1237 } 1238 if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { 1239 /* 1240 * If traced, always stop, and stay 1241 * stopped until released by the parent. 1242 */ 1243 p->p_xstat = sig; 1244 psignal(p->p_pptr, SIGCHLD); 1245 do { 1246 stop(p); 1247 mi_switch(p); 1248 } while (!trace_req(p) && p->p_flag & P_TRACED); 1249 1250 /* 1251 * If parent wants us to take the signal, 1252 * then it will leave it in p->p_xstat; 1253 * otherwise we just look for signals again. 1254 */ 1255 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1256 sig = p->p_xstat; 1257 if (sig == 0) 1258 continue; 1259 1260 /* 1261 * Put the new signal into p_siglist. If the 1262 * signal is being masked, look for other signals. 1263 */ 1264 SIGADDSET(p->p_siglist, sig); 1265 if (SIGISMEMBER(p->p_sigmask, sig)) 1266 continue; 1267 1268 /* 1269 * If the traced bit got turned off, go back up 1270 * to the top to rescan signals. This ensures 1271 * that p_sig* and ps_sigact are consistent. 1272 */ 1273 if ((p->p_flag & P_TRACED) == 0) 1274 continue; 1275 } 1276 1277 prop = sigprop(sig); 1278 1279 /* 1280 * Decide whether the signal should be returned. 1281 * Return the signal's number, or fall through 1282 * to clear it from the pending mask. 1283 */ 1284 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1285 1286 case (int)SIG_DFL: 1287 /* 1288 * Don't take default actions on system processes. 1289 */ 1290 if (p->p_pid <= 1) { 1291 #ifdef DIAGNOSTIC 1292 /* 1293 * Are you sure you want to ignore SIGSEGV 1294 * in init? XXX 1295 */ 1296 printf("Process (pid %lu) got signal %d\n", 1297 (u_long)p->p_pid, sig); 1298 #endif 1299 break; /* == ignore */ 1300 } 1301 1302 /* 1303 * Handle the in-kernel checkpoint action 1304 */ 1305 if (prop & SA_CKPT) { 1306 checkpoint_signal_handler(p); 1307 break; 1308 } 1309 1310 /* 1311 * If there is a pending stop signal to process 1312 * with default action, stop here, 1313 * then clear the signal. However, 1314 * if process is member of an orphaned 1315 * process group, ignore tty stop signals. 1316 */ 1317 if (prop & SA_STOP) { 1318 if (p->p_flag & P_TRACED || 1319 (p->p_pgrp->pg_jobc == 0 && 1320 prop & SA_TTYSTOP)) 1321 break; /* == ignore */ 1322 p->p_xstat = sig; 1323 stop(p); 1324 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1325 psignal(p->p_pptr, SIGCHLD); 1326 mi_switch(p); 1327 break; 1328 } else if (prop & SA_IGNORE) { 1329 /* 1330 * Except for SIGCONT, shouldn't get here. 1331 * Default action is to ignore; drop it. 1332 */ 1333 break; /* == ignore */ 1334 } else { 1335 return (sig); 1336 } 1337 1338 /*NOTREACHED*/ 1339 1340 case (int)SIG_IGN: 1341 /* 1342 * Masking above should prevent us ever trying 1343 * to take action on an ignored signal other 1344 * than SIGCONT, unless process is traced. 1345 */ 1346 if ((prop & SA_CONT) == 0 && 1347 (p->p_flag & P_TRACED) == 0) 1348 printf("issignal\n"); 1349 break; /* == ignore */ 1350 1351 default: 1352 /* 1353 * This signal has an action, let 1354 * postsig() process it. 1355 */ 1356 return (sig); 1357 } 1358 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1359 } 1360 /* NOTREACHED */ 1361 } 1362 1363 /* 1364 * Put the argument process into the stopped state and notify the parent 1365 * via wakeup. Signals are handled elsewhere. The process must not be 1366 * on the run queue. 1367 */ 1368 void 1369 stop(struct proc *p) 1370 { 1371 p->p_stat = SSTOP; 1372 p->p_flag &= ~P_WAITED; 1373 wakeup((caddr_t)p->p_pptr); 1374 } 1375 1376 /* 1377 * Take the action for the specified signal 1378 * from the current set of pending signals. 1379 */ 1380 void 1381 postsig(int sig) 1382 { 1383 struct proc *p = curproc; 1384 struct sigacts *ps = p->p_sigacts; 1385 sig_t action; 1386 sigset_t returnmask; 1387 int code; 1388 1389 KASSERT(sig != 0, ("postsig")); 1390 1391 SIGDELSET(p->p_siglist, sig); 1392 action = ps->ps_sigact[_SIG_IDX(sig)]; 1393 #ifdef KTRACE 1394 if (KTRPOINT(p->p_thread, KTR_PSIG)) 1395 ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ? 1396 &p->p_oldsigmask : &p->p_sigmask, 0); 1397 #endif 1398 STOPEVENT(p, S_SIG, sig); 1399 1400 if (action == SIG_DFL) { 1401 /* 1402 * Default action, where the default is to kill 1403 * the process. (Other cases were ignored above.) 1404 */ 1405 sigexit(p, sig); 1406 /* NOTREACHED */ 1407 } else { 1408 /* 1409 * If we get here, the signal must be caught. 1410 */ 1411 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), 1412 ("postsig action")); 1413 /* 1414 * Set the new mask value and also defer further 1415 * occurrences of this signal. 1416 * 1417 * Special case: user has done a sigsuspend. Here the 1418 * current mask is not of interest, but rather the 1419 * mask from before the sigsuspend is what we want 1420 * restored after the signal processing is completed. 1421 */ 1422 crit_enter(); 1423 if (p->p_flag & P_OLDMASK) { 1424 returnmask = p->p_oldsigmask; 1425 p->p_flag &= ~P_OLDMASK; 1426 } else { 1427 returnmask = p->p_sigmask; 1428 } 1429 1430 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1431 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1432 SIGADDSET(p->p_sigmask, sig); 1433 1434 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1435 /* 1436 * See kern_sigaction() for origin of this code. 1437 */ 1438 SIGDELSET(p->p_sigcatch, sig); 1439 if (sig != SIGCONT && 1440 sigprop(sig) & SA_IGNORE) 1441 SIGADDSET(p->p_sigignore, sig); 1442 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1443 } 1444 crit_exit(); 1445 p->p_stats->p_ru.ru_nsignals++; 1446 if (p->p_sig != sig) { 1447 code = 0; 1448 } else { 1449 code = p->p_code; 1450 p->p_code = 0; 1451 p->p_sig = 0; 1452 } 1453 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1454 } 1455 } 1456 1457 /* 1458 * Kill the current process for stated reason. 1459 */ 1460 void 1461 killproc(struct proc *p, char *why) 1462 { 1463 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, 1464 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1465 psignal(p, SIGKILL); 1466 } 1467 1468 /* 1469 * Force the current process to exit with the specified signal, dumping core 1470 * if appropriate. We bypass the normal tests for masked and caught signals, 1471 * allowing unrecoverable failures to terminate the process without changing 1472 * signal state. Mark the accounting record with the signal termination. 1473 * If dumping core, save the signal number for the debugger. Calls exit and 1474 * does not return. 1475 */ 1476 void 1477 sigexit(struct proc *p, int sig) 1478 { 1479 p->p_acflag |= AXSIG; 1480 if (sigprop(sig) & SA_CORE) { 1481 p->p_sig = sig; 1482 /* 1483 * Log signals which would cause core dumps 1484 * (Log as LOG_INFO to appease those who don't want 1485 * these messages.) 1486 * XXX : Todo, as well as euid, write out ruid too 1487 */ 1488 if (coredump(p) == 0) 1489 sig |= WCOREFLAG; 1490 if (kern_logsigexit) 1491 log(LOG_INFO, 1492 "pid %d (%s), uid %d: exited on signal %d%s\n", 1493 p->p_pid, p->p_comm, 1494 p->p_ucred ? p->p_ucred->cr_uid : -1, 1495 sig &~ WCOREFLAG, 1496 sig & WCOREFLAG ? " (core dumped)" : ""); 1497 } 1498 exit1(W_EXITCODE(0, sig)); 1499 /* NOTREACHED */ 1500 } 1501 1502 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1503 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1504 sizeof(corefilename), "process corefile name format string"); 1505 1506 /* 1507 * expand_name(name, uid, pid) 1508 * Expand the name described in corefilename, using name, uid, and pid. 1509 * corefilename is a printf-like string, with three format specifiers: 1510 * %N name of process ("name") 1511 * %P process id (pid) 1512 * %U user id (uid) 1513 * For example, "%N.core" is the default; they can be disabled completely 1514 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1515 * This is controlled by the sysctl variable kern.corefile (see above). 1516 */ 1517 1518 static char * 1519 expand_name(const char *name, uid_t uid, pid_t pid) 1520 { 1521 char *temp; 1522 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1523 int i, n; 1524 char *format = corefilename; 1525 size_t namelen; 1526 1527 temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1528 if (temp == NULL) 1529 return NULL; 1530 namelen = strlen(name); 1531 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1532 int l; 1533 switch (format[i]) { 1534 case '%': /* Format character */ 1535 i++; 1536 switch (format[i]) { 1537 case '%': 1538 temp[n++] = '%'; 1539 break; 1540 case 'N': /* process name */ 1541 if ((n + namelen) > MAXPATHLEN) { 1542 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1543 pid, name, uid, temp, name); 1544 free(temp, M_TEMP); 1545 return NULL; 1546 } 1547 memcpy(temp+n, name, namelen); 1548 n += namelen; 1549 break; 1550 case 'P': /* process id */ 1551 l = sprintf(buf, "%u", pid); 1552 if ((n + l) > MAXPATHLEN) { 1553 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1554 pid, name, uid, temp, name); 1555 free(temp, M_TEMP); 1556 return NULL; 1557 } 1558 memcpy(temp+n, buf, l); 1559 n += l; 1560 break; 1561 case 'U': /* user id */ 1562 l = sprintf(buf, "%u", uid); 1563 if ((n + l) > MAXPATHLEN) { 1564 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1565 pid, name, uid, temp, name); 1566 free(temp, M_TEMP); 1567 return NULL; 1568 } 1569 memcpy(temp+n, buf, l); 1570 n += l; 1571 break; 1572 default: 1573 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1574 } 1575 break; 1576 default: 1577 temp[n++] = format[i]; 1578 } 1579 } 1580 temp[n] = '\0'; 1581 return temp; 1582 } 1583 1584 /* 1585 * Dump a process' core. The main routine does some 1586 * policy checking, and creates the name of the coredump; 1587 * then it passes on a vnode and a size limit to the process-specific 1588 * coredump routine if there is one; if there _is not_ one, it returns 1589 * ENOSYS; otherwise it returns the error from the process-specific routine. 1590 */ 1591 1592 static int 1593 coredump(struct proc *p) 1594 { 1595 struct vnode *vp; 1596 struct ucred *cred = p->p_ucred; 1597 struct thread *td = p->p_thread; 1598 struct flock lf; 1599 struct nlookupdata nd; 1600 struct vattr vattr; 1601 int error, error1; 1602 char *name; /* name of corefile */ 1603 off_t limit; 1604 1605 STOPEVENT(p, S_CORE, 0); 1606 1607 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1608 return (EFAULT); 1609 1610 /* 1611 * Note that the bulk of limit checking is done after 1612 * the corefile is created. The exception is if the limit 1613 * for corefiles is 0, in which case we don't bother 1614 * creating the corefile at all. This layout means that 1615 * a corefile is truncated instead of not being created, 1616 * if it is larger than the limit. 1617 */ 1618 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1619 if (limit == 0) 1620 return EFBIG; 1621 1622 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1623 if (name == NULL) 1624 return (EINVAL); 1625 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1626 if (error == 0) 1627 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1628 free(name, M_TEMP); 1629 if (error) { 1630 nlookup_done(&nd); 1631 return (error); 1632 } 1633 vp = nd.nl_open_vp; 1634 nd.nl_open_vp = NULL; 1635 nlookup_done(&nd); 1636 1637 VOP_UNLOCK(vp, 0, td); 1638 lf.l_whence = SEEK_SET; 1639 lf.l_start = 0; 1640 lf.l_len = 0; 1641 lf.l_type = F_WRLCK; 1642 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK); 1643 if (error) 1644 goto out2; 1645 1646 /* Don't dump to non-regular files or files with links. */ 1647 if (vp->v_type != VREG || 1648 VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) { 1649 error = EFAULT; 1650 goto out1; 1651 } 1652 1653 VATTR_NULL(&vattr); 1654 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1655 vattr.va_size = 0; 1656 VOP_LEASE(vp, td, cred, LEASE_WRITE); 1657 VOP_SETATTR(vp, &vattr, cred, td); 1658 p->p_acflag |= ACORE; 1659 VOP_UNLOCK(vp, 0, td); 1660 1661 error = p->p_sysent->sv_coredump ? 1662 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1663 1664 out1: 1665 lf.l_type = F_UNLCK; 1666 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 1667 out2: 1668 error1 = vn_close(vp, FWRITE, td); 1669 if (error == 0) 1670 error = error1; 1671 return (error); 1672 } 1673 1674 /* 1675 * Nonexistent system call-- signal process (may want to handle it). 1676 * Flag error in case process won't see signal immediately (blocked or ignored). 1677 */ 1678 /* ARGSUSED */ 1679 int 1680 nosys(struct nosys_args *args) 1681 { 1682 psignal(curproc, SIGSYS); 1683 return (EINVAL); 1684 } 1685 1686 /* 1687 * Send a SIGIO or SIGURG signal to a process or process group using 1688 * stored credentials rather than those of the current process. 1689 */ 1690 void 1691 pgsigio(struct sigio *sigio, int sig, int checkctty) 1692 { 1693 if (sigio == NULL) 1694 return; 1695 1696 if (sigio->sio_pgid > 0) { 1697 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1698 sigio->sio_proc)) 1699 psignal(sigio->sio_proc, sig); 1700 } else if (sigio->sio_pgid < 0) { 1701 struct proc *p; 1702 1703 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) 1704 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1705 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1706 psignal(p, sig); 1707 } 1708 } 1709 1710 static int 1711 filt_sigattach(struct knote *kn) 1712 { 1713 struct proc *p = curproc; 1714 1715 kn->kn_ptr.p_proc = p; 1716 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1717 1718 /* XXX lock the proc here while adding to the list? */ 1719 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1720 1721 return (0); 1722 } 1723 1724 static void 1725 filt_sigdetach(struct knote *kn) 1726 { 1727 struct proc *p = kn->kn_ptr.p_proc; 1728 1729 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1730 } 1731 1732 /* 1733 * signal knotes are shared with proc knotes, so we apply a mask to 1734 * the hint in order to differentiate them from process hints. This 1735 * could be avoided by using a signal-specific knote list, but probably 1736 * isn't worth the trouble. 1737 */ 1738 static int 1739 filt_signal(struct knote *kn, long hint) 1740 { 1741 if (hint & NOTE_SIGNAL) { 1742 hint &= ~NOTE_SIGNAL; 1743 1744 if (kn->kn_id == hint) 1745 kn->kn_data++; 1746 } 1747 return (kn->kn_data != 0); 1748 } 1749