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 1.39 2005/11/14 18:50:05 dillon Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/sysproto.h> 49 #include <sys/signalvar.h> 50 #include <sys/resourcevar.h> 51 #include <sys/vnode.h> 52 #include <sys/event.h> 53 #include <sys/proc.h> 54 #include <sys/nlookup.h> 55 #include <sys/pioctl.h> 56 #include <sys/systm.h> 57 #include <sys/acct.h> 58 #include <sys/fcntl.h> 59 #include <sys/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 #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 crit_enter(); 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 crit_exit(); 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. 417 */ 418 int 419 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 420 { 421 struct thread *td = curthread; 422 struct proc *p = td->td_proc; 423 int error; 424 425 if (oset != NULL) 426 *oset = p->p_sigmask; 427 428 error = 0; 429 if (set != NULL) { 430 switch (how) { 431 case SIG_BLOCK: 432 SIG_CANTMASK(*set); 433 SIGSETOR(p->p_sigmask, *set); 434 break; 435 case SIG_UNBLOCK: 436 SIGSETNAND(p->p_sigmask, *set); 437 break; 438 case SIG_SETMASK: 439 SIG_CANTMASK(*set); 440 p->p_sigmask = *set; 441 break; 442 default: 443 error = EINVAL; 444 break; 445 } 446 } 447 return (error); 448 } 449 450 /* 451 * sigprocmask() - MP SAFE 452 */ 453 int 454 sigprocmask(struct sigprocmask_args *uap) 455 { 456 sigset_t set, oset; 457 sigset_t *setp, *osetp; 458 int error; 459 460 setp = (uap->set != NULL) ? &set : NULL; 461 osetp = (uap->oset != NULL) ? &oset : NULL; 462 if (setp) { 463 error = copyin(uap->set, setp, sizeof(set)); 464 if (error) 465 return (error); 466 } 467 error = kern_sigprocmask(uap->how, setp, osetp); 468 if (osetp && !error) { 469 error = copyout(osetp, uap->oset, sizeof(oset)); 470 } 471 return (error); 472 } 473 474 int 475 kern_sigpending(struct __sigset *set) 476 { 477 struct thread *td = curthread; 478 struct proc *p = td->td_proc; 479 480 *set = p->p_siglist; 481 482 return (0); 483 } 484 485 int 486 sigpending(struct sigpending_args *uap) 487 { 488 sigset_t set; 489 int error; 490 491 error = kern_sigpending(&set); 492 493 if (error == 0) 494 error = copyout(&set, uap->set, sizeof(set)); 495 return (error); 496 } 497 498 /* 499 * Suspend process until signal, providing mask to be set 500 * in the meantime. 501 */ 502 int 503 kern_sigsuspend(struct __sigset *set) 504 { 505 struct thread *td = curthread; 506 struct proc *p = td->td_proc; 507 struct sigacts *ps = p->p_sigacts; 508 509 /* 510 * When returning from sigsuspend, we want 511 * the old mask to be restored after the 512 * signal handler has finished. Thus, we 513 * save it here and mark the sigacts structure 514 * to indicate this. 515 */ 516 p->p_oldsigmask = p->p_sigmask; 517 p->p_flag |= P_OLDMASK; 518 519 SIG_CANTMASK(*set); 520 p->p_sigmask = *set; 521 while (tsleep(ps, PCATCH, "pause", 0) == 0) 522 /* void */; 523 /* always return EINTR rather than ERESTART... */ 524 return (EINTR); 525 } 526 527 /* 528 * Note nonstandard calling convention: libc stub passes mask, not 529 * pointer, to save a copyin. 530 */ 531 int 532 sigsuspend(struct sigsuspend_args *uap) 533 { 534 sigset_t mask; 535 int error; 536 537 error = copyin(uap->sigmask, &mask, sizeof(mask)); 538 if (error) 539 return (error); 540 541 error = kern_sigsuspend(&mask); 542 543 return (error); 544 } 545 546 int 547 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 548 { 549 struct thread *td = curthread; 550 struct proc *p = td->td_proc; 551 552 if ((p->p_flag & P_ALTSTACK) == 0) 553 p->p_sigstk.ss_flags |= SS_DISABLE; 554 555 if (oss) 556 *oss = p->p_sigstk; 557 558 if (ss) { 559 if (ss->ss_flags & SS_DISABLE) { 560 if (p->p_sigstk.ss_flags & SS_ONSTACK) 561 return (EINVAL); 562 p->p_flag &= ~P_ALTSTACK; 563 p->p_sigstk.ss_flags = ss->ss_flags; 564 } else { 565 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 566 return (ENOMEM); 567 p->p_flag |= P_ALTSTACK; 568 p->p_sigstk = *ss; 569 } 570 } 571 572 return (0); 573 } 574 575 int 576 sigaltstack(struct sigaltstack_args *uap) 577 { 578 stack_t ss, oss; 579 int error; 580 581 if (uap->ss) { 582 error = copyin(uap->ss, &ss, sizeof(ss)); 583 if (error) 584 return (error); 585 } 586 587 error = kern_sigaltstack(uap->ss ? &ss : NULL, 588 uap->oss ? &oss : NULL); 589 590 if (error == 0 && uap->oss) 591 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 592 return (error); 593 } 594 595 /* 596 * Common code for kill process group/broadcast kill. 597 * cp is calling process. 598 */ 599 static int 600 killpg(int sig, int pgid, int all) 601 { 602 struct proc *cp = curproc; 603 struct proc *p; 604 struct pgrp *pgrp; 605 int nfound = 0; 606 607 if (all) { 608 /* 609 * broadcast 610 */ 611 FOREACH_PROC_IN_SYSTEM(p) { 612 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 613 p == cp || !CANSIGNAL(p, sig)) 614 continue; 615 nfound++; 616 if (sig) 617 psignal(p, sig); 618 } 619 } else { 620 if (pgid == 0) { 621 /* 622 * zero pgid means send to my process group. 623 */ 624 pgrp = cp->p_pgrp; 625 } else { 626 pgrp = pgfind(pgid); 627 if (pgrp == NULL) 628 return (ESRCH); 629 } 630 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 631 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 632 p->p_stat == SZOMB || 633 !CANSIGNAL(p, sig)) 634 continue; 635 nfound++; 636 if (sig) 637 psignal(p, sig); 638 } 639 } 640 return (nfound ? 0 : ESRCH); 641 } 642 643 int 644 kern_kill(int sig, int pid) 645 { 646 struct thread *td = curthread; 647 struct proc *p = td->td_proc; 648 649 if ((u_int)sig > _SIG_MAXSIG) 650 return (EINVAL); 651 if (pid > 0) { 652 /* kill single process */ 653 if ((p = pfind(pid)) == NULL) 654 return (ESRCH); 655 if (!CANSIGNAL(p, sig)) 656 return (EPERM); 657 if (sig) 658 psignal(p, sig); 659 return (0); 660 } 661 switch (pid) { 662 case -1: /* broadcast signal */ 663 return (killpg(sig, 0, 1)); 664 case 0: /* signal own process group */ 665 return (killpg(sig, 0, 0)); 666 default: /* negative explicit process group */ 667 return (killpg(sig, -pid, 0)); 668 } 669 /* NOTREACHED */ 670 } 671 672 int 673 kill(struct kill_args *uap) 674 { 675 int error; 676 677 error = kern_kill(uap->signum, uap->pid); 678 679 return (error); 680 } 681 682 /* 683 * Send a signal to a process group. 684 */ 685 void 686 gsignal(int pgid, int sig) 687 { 688 struct pgrp *pgrp; 689 690 if (pgid && (pgrp = pgfind(pgid))) 691 pgsignal(pgrp, sig, 0); 692 } 693 694 /* 695 * Send a signal to a process group. If checktty is 1, 696 * limit to members which have a controlling terminal. 697 */ 698 void 699 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 700 { 701 struct proc *p; 702 703 if (pgrp) 704 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) 705 if (checkctty == 0 || p->p_flag & P_CONTROLT) 706 psignal(p, sig); 707 } 708 709 /* 710 * Send a signal caused by a trap to the current process. 711 * If it will be caught immediately, deliver it with correct code. 712 * Otherwise, post it normally. 713 */ 714 void 715 trapsignal(struct proc *p, int sig, u_long code) 716 { 717 struct sigacts *ps = p->p_sigacts; 718 719 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 720 !SIGISMEMBER(p->p_sigmask, sig)) { 721 p->p_stats->p_ru.ru_nsignals++; 722 #ifdef KTRACE 723 if (KTRPOINT(p->p_thread, KTR_PSIG)) 724 ktrpsig(p->p_tracep, sig, ps->ps_sigact[_SIG_IDX(sig)], 725 &p->p_sigmask, code); 726 #endif 727 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 728 &p->p_sigmask, code); 729 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 730 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 731 SIGADDSET(p->p_sigmask, sig); 732 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 733 /* 734 * See kern_sigaction() for origin of this code. 735 */ 736 SIGDELSET(p->p_sigcatch, sig); 737 if (sig != SIGCONT && 738 sigprop(sig) & SA_IGNORE) 739 SIGADDSET(p->p_sigignore, sig); 740 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 741 } 742 } else { 743 p->p_code = code; /* XXX for core dump/debugger */ 744 p->p_sig = sig; /* XXX to verify code */ 745 psignal(p, sig); 746 } 747 } 748 749 /* 750 * Send the signal to the process. If the signal has an action, the action 751 * is usually performed by the target process rather than the caller; we add 752 * the signal to the set of pending signals for the process. 753 * 754 * Exceptions: 755 * o When a stop signal is sent to a sleeping process that takes the 756 * default action, the process is stopped without awakening it. 757 * o SIGCONT restarts stopped processes (or puts them back to sleep) 758 * regardless of the signal action (eg, blocked or ignored). 759 * 760 * Other ignored signals are discarded immediately. 761 */ 762 void 763 psignal(struct proc *p, int sig) 764 { 765 struct lwp *lp = &p->p_lwp; 766 int prop; 767 sig_t action; 768 769 if (sig > _SIG_MAXSIG || sig <= 0) { 770 printf("psignal: signal %d\n", sig); 771 panic("psignal signal number"); 772 } 773 774 crit_enter(); 775 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 776 crit_exit(); 777 778 prop = sigprop(sig); 779 780 /* 781 * If proc is traced, always give parent a chance; 782 * if signal event is tracked by procfs, give *that* 783 * a chance, as well. 784 */ 785 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 786 action = SIG_DFL; 787 } else { 788 /* 789 * If the signal is being ignored, 790 * then we forget about it immediately. 791 * (Note: we don't set SIGCONT in p_sigignore, 792 * and if it is set to SIG_IGN, 793 * action will be SIG_DFL here.) 794 */ 795 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 796 return; 797 if (SIGISMEMBER(p->p_sigmask, sig)) 798 action = SIG_HOLD; 799 else if (SIGISMEMBER(p->p_sigcatch, sig)) 800 action = SIG_CATCH; 801 else 802 action = SIG_DFL; 803 } 804 805 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 806 (p->p_flag & P_TRACED) == 0) { 807 p->p_nice = NZERO; 808 } 809 810 /* 811 * If continuing, clear any pending STOP signals. 812 */ 813 if (prop & SA_CONT) 814 SIG_STOPSIGMASK(p->p_siglist); 815 816 if (prop & SA_STOP) { 817 /* 818 * If sending a tty stop signal to a member of an orphaned 819 * process group, discard the signal here if the action 820 * is default; don't stop the process below if sleeping, 821 * and don't clear any pending SIGCONT. 822 */ 823 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 824 action == SIG_DFL) { 825 return; 826 } 827 SIG_CONTSIGMASK(p->p_siglist); 828 } 829 SIGADDSET(p->p_siglist, sig); 830 831 /* 832 * Defer further processing for signals which are held, 833 * except that stopped processes must be continued by SIGCONT. 834 */ 835 if (action == SIG_HOLD) { 836 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0) 837 return; 838 } 839 840 crit_enter(); 841 842 /* 843 * Process is in tsleep and not stopped 844 */ 845 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) { 846 /* 847 * If the process is sleeping uninterruptibly 848 * we can't interrupt the sleep... the signal will 849 * be noticed when the process returns through 850 * trap() or syscall(). 851 */ 852 if ((p->p_flag & P_SINTR) == 0) 853 goto out; 854 855 /* 856 * If the 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 the process is stopped and traced, no further action 861 * is necessary. 862 */ 863 if (p->p_flag & P_TRACED) 864 goto run; 865 866 /* 867 * If the process is sleeping and SA_CONT, and the signal 868 * mode is SIG_DFL, then make the process runnable. 869 * 870 * However, do *NOT* set P_BREAKTSLEEP. We do not want 871 * a SIGCONT to terminate an interruptable tsleep early 872 * and generate a spurious EINTR. 873 */ 874 if ((prop & SA_CONT) && action == SIG_DFL) { 875 SIGDELSET(p->p_siglist, sig); 876 goto run_no_break; 877 } 878 879 /* 880 * If the process is sleeping and receives a STOP signal, 881 * process immediately if possible. All other (caught or 882 * default) signals cause the process to run. 883 */ 884 if (prop & SA_STOP) { 885 if (action != SIG_DFL) 886 goto run; 887 888 /* 889 * If a child holding parent blocked, stopping 890 * could cause deadlock. Take no action at this 891 * time. 892 */ 893 if (p->p_flag & P_PPWAIT) 894 goto out; 895 896 /* 897 * Do not actually try to manipulate the process 898 * while it is sleeping, simply set P_STOPPED to 899 * indicate that it should stop as soon as it safely 900 * can. 901 */ 902 SIGDELSET(p->p_siglist, sig); 903 p->p_flag |= P_STOPPED; 904 p->p_flag &= ~P_WAITED; 905 p->p_xstat = sig; 906 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 907 psignal(p->p_pptr, SIGCHLD); 908 goto out; 909 } 910 911 /* 912 * Otherwise the signal can interrupt the sleep. 913 */ 914 goto run; 915 } 916 917 /* 918 * Process is in tsleep and is stopped 919 */ 920 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) { 921 /* 922 * If the process is stopped and is being traced, then no 923 * further action is necessary. 924 */ 925 if (p->p_flag & P_TRACED) 926 goto out; 927 928 /* 929 * If the process is stopped and receives a KILL signal, 930 * make the process runnable. 931 */ 932 if (sig == SIGKILL) 933 goto run; 934 935 /* 936 * If the process is stopped and receives a CONT signal, 937 * then try to make the process runnable again. 938 */ 939 if (prop & SA_CONT) { 940 /* 941 * If SIGCONT is default (or ignored), we continue the 942 * process but don't leave the signal in p_siglist, as 943 * it has no further action. If SIGCONT is held, we 944 * continue the process and leave the signal in 945 * p_siglist. If the process catches SIGCONT, let it 946 * handle the signal itself. 947 */ 948 if (action == SIG_DFL) 949 SIGDELSET(p->p_siglist, sig); 950 if (action == SIG_CATCH) 951 goto run; 952 953 /* 954 * Make runnable but do not break a tsleep unless 955 * some other signal was pending. 956 */ 957 goto run_no_break; 958 } 959 960 /* 961 * If the process is stopped and receives another STOP 962 * signal, we do not need to stop it again. If we did 963 * the shell could get confused. 964 */ 965 if (prop & SA_STOP) { 966 SIGDELSET(p->p_siglist, sig); 967 goto out; 968 } 969 970 /* 971 * Otherwise the process is sleeping interruptably but 972 * is stopped, just set the P_BREAKTSLEEP flag and take 973 * no further action. The next runnable action will wake 974 * the process up. 975 */ 976 p->p_flag |= P_BREAKTSLEEP; 977 goto out; 978 } 979 980 /* 981 * Otherwise the process is running 982 * 983 * SRUN, SIDL, SZOMB do nothing with the signal, 984 * other than kicking ourselves if we are running. 985 * It will either never be noticed, or noticed very soon. 986 * 987 * Note that p_thread may be NULL or may not be completely 988 * initialized if the process is in the SIDL or SZOMB state. 989 * 990 * For SMP we may have to forward the request to another cpu. 991 * YYY the MP lock prevents the target process from moving 992 * to another cpu, see kern/kern_switch.c 993 * 994 * If the target thread is waiting on its message port, 995 * wakeup the target thread so it can check (or ignore) 996 * the new signal. YYY needs cleanup. 997 */ 998 if (lp == lwkt_preempted_proc()) { 999 signotify(); 1000 } else if (p->p_stat == SRUN) { 1001 struct thread *td = p->p_thread; 1002 1003 KASSERT(td != NULL, 1004 ("pid %d NULL p_thread stat %d flags %08x", 1005 p->p_pid, p->p_stat, p->p_flag)); 1006 1007 #ifdef SMP 1008 if (td->td_gd != mycpu) 1009 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1010 else 1011 #endif 1012 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1013 lwkt_schedule(td); 1014 } 1015 goto out; 1016 /*NOTREACHED*/ 1017 run: 1018 /* 1019 * Make runnable and break out of any tsleep as well. 1020 */ 1021 p->p_flag |= P_BREAKTSLEEP; 1022 run_no_break: 1023 setrunnable(p); 1024 out: 1025 crit_exit(); 1026 } 1027 1028 #ifdef SMP 1029 1030 /* 1031 * This function is called via an IPI. We will be in a critical section but 1032 * the MP lock will NOT be held. Also note that by the time the ipi message 1033 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1034 */ 1035 static void 1036 signotify_remote(void *arg) 1037 { 1038 struct lwp *lp = arg; 1039 1040 if (lp == lwkt_preempted_proc()) { 1041 signotify(); 1042 } else { 1043 struct thread *td = lp->lwp_thread; 1044 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1045 lwkt_schedule(td); 1046 } 1047 } 1048 1049 #endif 1050 1051 static int 1052 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1053 { 1054 sigset_t savedmask, set; 1055 struct proc *p = curproc; 1056 int error, sig, hz, timevalid = 0; 1057 struct timespec rts, ets, ts; 1058 struct timeval tv; 1059 1060 error = 0; 1061 sig = 0; 1062 SIG_CANTMASK(waitset); 1063 savedmask = p->p_sigmask; 1064 1065 if (timeout) { 1066 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1067 timeout->tv_nsec < 1000000000) { 1068 timevalid = 1; 1069 getnanouptime(&rts); 1070 ets = rts; 1071 timespecadd(&ets, timeout); 1072 } 1073 } 1074 1075 for (;;) { 1076 set = p->p_siglist; 1077 SIGSETAND(set, waitset); 1078 if ((sig = sig_ffs(&set)) != 0) { 1079 SIGFILLSET(p->p_sigmask); 1080 SIGDELSET(p->p_sigmask, sig); 1081 SIG_CANTMASK(p->p_sigmask); 1082 sig = issignal(p); 1083 /* 1084 * It may be a STOP signal, in the case, issignal 1085 * returns 0, because we may stop there, and new 1086 * signal can come in, we should restart if we got 1087 * nothing. 1088 */ 1089 if (sig == 0) 1090 continue; 1091 else 1092 break; 1093 } 1094 1095 /* 1096 * Previous checking got nothing, and we retried but still 1097 * got nothing, we should return the error status. 1098 */ 1099 if (error) 1100 break; 1101 1102 /* 1103 * POSIX says this must be checked after looking for pending 1104 * signals. 1105 */ 1106 if (timeout) { 1107 if (!timevalid) { 1108 error = EINVAL; 1109 break; 1110 } 1111 getnanouptime(&rts); 1112 if (timespeccmp(&rts, &ets, >=)) { 1113 error = EAGAIN; 1114 break; 1115 } 1116 ts = ets; 1117 timespecsub(&ts, &rts); 1118 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1119 hz = tvtohz_high(&tv); 1120 } else 1121 hz = 0; 1122 1123 p->p_sigmask = savedmask; 1124 SIGSETNAND(p->p_sigmask, waitset); 1125 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1126 if (timeout) { 1127 if (error == ERESTART) { 1128 /* can not restart a timeout wait. */ 1129 error = EINTR; 1130 } else if (error == EAGAIN) { 1131 /* will calculate timeout by ourself. */ 1132 error = 0; 1133 } 1134 } 1135 /* Retry ... */ 1136 } 1137 1138 p->p_sigmask = savedmask; 1139 if (sig) { 1140 error = 0; 1141 bzero(info, sizeof(*info)); 1142 info->si_signo = sig; 1143 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1144 } 1145 return (error); 1146 } 1147 1148 int 1149 sigtimedwait(struct sigtimedwait_args *uap) 1150 { 1151 struct timespec ts; 1152 struct timespec *timeout; 1153 sigset_t set; 1154 siginfo_t info; 1155 int error; 1156 1157 if (uap->timeout) { 1158 error = copyin(uap->timeout, &ts, sizeof(ts)); 1159 if (error) 1160 return (error); 1161 timeout = &ts; 1162 } else { 1163 timeout = NULL; 1164 } 1165 error = copyin(uap->set, &set, sizeof(set)); 1166 if (error) 1167 return (error); 1168 error = kern_sigtimedwait(set, &info, timeout); 1169 if (error) 1170 return (error); 1171 if (uap->info) 1172 error = copyout(&info, uap->info, sizeof(info)); 1173 /* Repost if we got an error. */ 1174 if (error) 1175 psignal(curproc, info.si_signo); 1176 else 1177 uap->sysmsg_result = info.si_signo; 1178 return (error); 1179 } 1180 1181 int 1182 sigwaitinfo(struct sigwaitinfo_args *uap) 1183 { 1184 siginfo_t info; 1185 sigset_t set; 1186 int error; 1187 1188 error = copyin(uap->set, &set, sizeof(set)); 1189 if (error) 1190 return (error); 1191 error = kern_sigtimedwait(set, &info, NULL); 1192 if (error) 1193 return (error); 1194 if (uap->info) 1195 error = copyout(&info, uap->info, sizeof(info)); 1196 /* Repost if we got an error. */ 1197 if (error) 1198 psignal(curproc, info.si_signo); 1199 else 1200 uap->sysmsg_result = info.si_signo; 1201 return (error); 1202 } 1203 1204 /* 1205 * If the current process has received a signal that would interrupt a 1206 * system call, return EINTR or ERESTART as appropriate. 1207 */ 1208 int 1209 iscaught(struct proc *p) 1210 { 1211 int sig; 1212 1213 if (p) { 1214 if ((sig = CURSIG(p)) != 0) { 1215 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1216 return (EINTR); 1217 return (ERESTART); 1218 } 1219 } 1220 return(EWOULDBLOCK); 1221 } 1222 1223 /* 1224 * If the current process has received a signal (should be caught or cause 1225 * termination, should interrupt current syscall), return the signal number. 1226 * Stop signals with default action are processed immediately, then cleared; 1227 * they aren't returned. This is checked after each entry to the system for 1228 * a syscall or trap (though this can usually be done without calling issignal 1229 * by checking the pending signal masks in the CURSIG macro.) The normal call 1230 * sequence is 1231 * 1232 * while (sig = CURSIG(curproc)) 1233 * postsig(sig); 1234 */ 1235 int 1236 issignal(struct proc *p) 1237 { 1238 sigset_t mask; 1239 int sig, prop; 1240 1241 for (;;) { 1242 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1243 1244 mask = p->p_siglist; 1245 SIGSETNAND(mask, p->p_sigmask); 1246 if (p->p_flag & P_PPWAIT) 1247 SIG_STOPSIGMASK(mask); 1248 if (!SIGNOTEMPTY(mask)) /* no signal to send */ 1249 return (0); 1250 sig = sig_ffs(&mask); 1251 1252 STOPEVENT(p, S_SIG, sig); 1253 1254 /* 1255 * We should see pending but ignored signals 1256 * only if P_TRACED was on when they were posted. 1257 */ 1258 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1259 SIGDELSET(p->p_siglist, sig); 1260 continue; 1261 } 1262 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1263 /* 1264 * If traced, always stop, and stay stopped until 1265 * released by the parent. 1266 * 1267 * NOTE: P_STOPPED may get cleared during the loop, 1268 * but we do not re-notify the parent if we have 1269 * to loop several times waiting for the parent 1270 * to let us continue. 1271 */ 1272 p->p_xstat = sig; 1273 p->p_flag |= P_STOPPED; 1274 p->p_flag &= ~P_WAITED; 1275 psignal(p->p_pptr, SIGCHLD); 1276 do { 1277 tstop(p); 1278 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1279 p->p_flag &= ~P_STOPPED; 1280 1281 /* 1282 * If parent wants us to take the signal, 1283 * then it will leave it in p->p_xstat; 1284 * otherwise we just look for signals again. 1285 */ 1286 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1287 sig = p->p_xstat; 1288 if (sig == 0) 1289 continue; 1290 1291 /* 1292 * Put the new signal into p_siglist. If the 1293 * signal is being masked, look for other signals. 1294 */ 1295 SIGADDSET(p->p_siglist, sig); 1296 if (SIGISMEMBER(p->p_sigmask, sig)) 1297 continue; 1298 1299 /* 1300 * If the traced bit got turned off, go back up 1301 * to the top to rescan signals. This ensures 1302 * that p_sig* and ps_sigact are consistent. 1303 */ 1304 if ((p->p_flag & P_TRACED) == 0) 1305 continue; 1306 } 1307 1308 prop = sigprop(sig); 1309 1310 /* 1311 * Decide whether the signal should be returned. 1312 * Return the signal's number, or fall through 1313 * to clear it from the pending mask. 1314 */ 1315 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1316 case (int)SIG_DFL: 1317 /* 1318 * Don't take default actions on system processes. 1319 */ 1320 if (p->p_pid <= 1) { 1321 #ifdef DIAGNOSTIC 1322 /* 1323 * Are you sure you want to ignore SIGSEGV 1324 * in init? XXX 1325 */ 1326 printf("Process (pid %lu) got signal %d\n", 1327 (u_long)p->p_pid, sig); 1328 #endif 1329 break; /* == ignore */ 1330 } 1331 1332 /* 1333 * Handle the in-kernel checkpoint action 1334 */ 1335 if (prop & SA_CKPT) { 1336 checkpoint_signal_handler(p); 1337 break; 1338 } 1339 1340 /* 1341 * If there is a pending stop signal to process 1342 * with default action, stop here, 1343 * then clear the signal. However, 1344 * if process is member of an orphaned 1345 * process group, ignore tty stop signals. 1346 */ 1347 if (prop & SA_STOP) { 1348 if (p->p_flag & P_TRACED || 1349 (p->p_pgrp->pg_jobc == 0 && 1350 prop & SA_TTYSTOP)) 1351 break; /* == ignore */ 1352 p->p_xstat = sig; 1353 p->p_flag |= P_STOPPED; 1354 p->p_flag &= ~P_WAITED; 1355 1356 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1357 psignal(p->p_pptr, SIGCHLD); 1358 while (p->p_flag & P_STOPPED) { 1359 tstop(p); 1360 } 1361 break; 1362 } else if (prop & SA_IGNORE) { 1363 /* 1364 * Except for SIGCONT, shouldn't get here. 1365 * Default action is to ignore; drop it. 1366 */ 1367 break; /* == ignore */ 1368 } else { 1369 return (sig); 1370 } 1371 1372 /*NOTREACHED*/ 1373 1374 case (int)SIG_IGN: 1375 /* 1376 * Masking above should prevent us ever trying 1377 * to take action on an ignored signal other 1378 * than SIGCONT, unless process is traced. 1379 */ 1380 if ((prop & SA_CONT) == 0 && 1381 (p->p_flag & P_TRACED) == 0) 1382 printf("issignal\n"); 1383 break; /* == ignore */ 1384 1385 default: 1386 /* 1387 * This signal has an action, let 1388 * postsig() process it. 1389 */ 1390 return (sig); 1391 } 1392 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1393 } 1394 /* NOTREACHED */ 1395 } 1396 1397 /* 1398 * Take the action for the specified signal 1399 * from the current set of pending signals. 1400 */ 1401 void 1402 postsig(int sig) 1403 { 1404 struct proc *p = curproc; 1405 struct sigacts *ps = p->p_sigacts; 1406 sig_t action; 1407 sigset_t returnmask; 1408 int code; 1409 1410 KASSERT(sig != 0, ("postsig")); 1411 1412 SIGDELSET(p->p_siglist, sig); 1413 action = ps->ps_sigact[_SIG_IDX(sig)]; 1414 #ifdef KTRACE 1415 if (KTRPOINT(p->p_thread, KTR_PSIG)) 1416 ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ? 1417 &p->p_oldsigmask : &p->p_sigmask, 0); 1418 #endif 1419 STOPEVENT(p, S_SIG, sig); 1420 1421 if (action == SIG_DFL) { 1422 /* 1423 * Default action, where the default is to kill 1424 * the process. (Other cases were ignored above.) 1425 */ 1426 sigexit(p, sig); 1427 /* NOTREACHED */ 1428 } else { 1429 /* 1430 * If we get here, the signal must be caught. 1431 */ 1432 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), 1433 ("postsig action")); 1434 /* 1435 * Set the new mask value and also defer further 1436 * occurrences of this signal. 1437 * 1438 * Special case: user has done a sigsuspend. Here the 1439 * current mask is not of interest, but rather the 1440 * mask from before the sigsuspend is what we want 1441 * restored after the signal processing is completed. 1442 */ 1443 crit_enter(); 1444 if (p->p_flag & P_OLDMASK) { 1445 returnmask = p->p_oldsigmask; 1446 p->p_flag &= ~P_OLDMASK; 1447 } else { 1448 returnmask = p->p_sigmask; 1449 } 1450 1451 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1452 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1453 SIGADDSET(p->p_sigmask, sig); 1454 1455 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1456 /* 1457 * See kern_sigaction() for origin of this code. 1458 */ 1459 SIGDELSET(p->p_sigcatch, sig); 1460 if (sig != SIGCONT && 1461 sigprop(sig) & SA_IGNORE) 1462 SIGADDSET(p->p_sigignore, sig); 1463 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1464 } 1465 crit_exit(); 1466 p->p_stats->p_ru.ru_nsignals++; 1467 if (p->p_sig != sig) { 1468 code = 0; 1469 } else { 1470 code = p->p_code; 1471 p->p_code = 0; 1472 p->p_sig = 0; 1473 } 1474 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1475 } 1476 } 1477 1478 /* 1479 * Kill the current process for stated reason. 1480 */ 1481 void 1482 killproc(struct proc *p, char *why) 1483 { 1484 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, 1485 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1486 psignal(p, SIGKILL); 1487 } 1488 1489 /* 1490 * Force the current process to exit with the specified signal, dumping core 1491 * if appropriate. We bypass the normal tests for masked and caught signals, 1492 * allowing unrecoverable failures to terminate the process without changing 1493 * signal state. Mark the accounting record with the signal termination. 1494 * If dumping core, save the signal number for the debugger. Calls exit and 1495 * does not return. 1496 */ 1497 void 1498 sigexit(struct proc *p, int sig) 1499 { 1500 p->p_acflag |= AXSIG; 1501 if (sigprop(sig) & SA_CORE) { 1502 p->p_sig = sig; 1503 /* 1504 * Log signals which would cause core dumps 1505 * (Log as LOG_INFO to appease those who don't want 1506 * these messages.) 1507 * XXX : Todo, as well as euid, write out ruid too 1508 */ 1509 if (coredump(p) == 0) 1510 sig |= WCOREFLAG; 1511 if (kern_logsigexit) 1512 log(LOG_INFO, 1513 "pid %d (%s), uid %d: exited on signal %d%s\n", 1514 p->p_pid, p->p_comm, 1515 p->p_ucred ? p->p_ucred->cr_uid : -1, 1516 sig &~ WCOREFLAG, 1517 sig & WCOREFLAG ? " (core dumped)" : ""); 1518 } 1519 exit1(W_EXITCODE(0, sig)); 1520 /* NOTREACHED */ 1521 } 1522 1523 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1524 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1525 sizeof(corefilename), "process corefile name format string"); 1526 1527 /* 1528 * expand_name(name, uid, pid) 1529 * Expand the name described in corefilename, using name, uid, and pid. 1530 * corefilename is a printf-like string, with three format specifiers: 1531 * %N name of process ("name") 1532 * %P process id (pid) 1533 * %U user id (uid) 1534 * For example, "%N.core" is the default; they can be disabled completely 1535 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1536 * This is controlled by the sysctl variable kern.corefile (see above). 1537 */ 1538 1539 static char * 1540 expand_name(const char *name, uid_t uid, pid_t pid) 1541 { 1542 char *temp; 1543 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1544 int i, n; 1545 char *format = corefilename; 1546 size_t namelen; 1547 1548 temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1549 if (temp == NULL) 1550 return NULL; 1551 namelen = strlen(name); 1552 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1553 int l; 1554 switch (format[i]) { 1555 case '%': /* Format character */ 1556 i++; 1557 switch (format[i]) { 1558 case '%': 1559 temp[n++] = '%'; 1560 break; 1561 case 'N': /* process name */ 1562 if ((n + namelen) > MAXPATHLEN) { 1563 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1564 pid, name, uid, temp, name); 1565 free(temp, M_TEMP); 1566 return NULL; 1567 } 1568 memcpy(temp+n, name, namelen); 1569 n += namelen; 1570 break; 1571 case 'P': /* process id */ 1572 l = sprintf(buf, "%u", pid); 1573 if ((n + l) > MAXPATHLEN) { 1574 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1575 pid, name, uid, temp, name); 1576 free(temp, M_TEMP); 1577 return NULL; 1578 } 1579 memcpy(temp+n, buf, l); 1580 n += l; 1581 break; 1582 case 'U': /* user id */ 1583 l = sprintf(buf, "%u", uid); 1584 if ((n + l) > MAXPATHLEN) { 1585 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1586 pid, name, uid, temp, name); 1587 free(temp, M_TEMP); 1588 return NULL; 1589 } 1590 memcpy(temp+n, buf, l); 1591 n += l; 1592 break; 1593 default: 1594 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1595 } 1596 break; 1597 default: 1598 temp[n++] = format[i]; 1599 } 1600 } 1601 temp[n] = '\0'; 1602 return temp; 1603 } 1604 1605 /* 1606 * Dump a process' core. The main routine does some 1607 * policy checking, and creates the name of the coredump; 1608 * then it passes on a vnode and a size limit to the process-specific 1609 * coredump routine if there is one; if there _is not_ one, it returns 1610 * ENOSYS; otherwise it returns the error from the process-specific routine. 1611 */ 1612 1613 static int 1614 coredump(struct proc *p) 1615 { 1616 struct vnode *vp; 1617 struct ucred *cred = p->p_ucred; 1618 struct thread *td = p->p_thread; 1619 struct flock lf; 1620 struct nlookupdata nd; 1621 struct vattr vattr; 1622 int error, error1; 1623 char *name; /* name of corefile */ 1624 off_t limit; 1625 1626 STOPEVENT(p, S_CORE, 0); 1627 1628 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1629 return (EFAULT); 1630 1631 /* 1632 * Note that the bulk of limit checking is done after 1633 * the corefile is created. The exception is if the limit 1634 * for corefiles is 0, in which case we don't bother 1635 * creating the corefile at all. This layout means that 1636 * a corefile is truncated instead of not being created, 1637 * if it is larger than the limit. 1638 */ 1639 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1640 if (limit == 0) 1641 return EFBIG; 1642 1643 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1644 if (name == NULL) 1645 return (EINVAL); 1646 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1647 if (error == 0) 1648 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1649 free(name, M_TEMP); 1650 if (error) { 1651 nlookup_done(&nd); 1652 return (error); 1653 } 1654 vp = nd.nl_open_vp; 1655 nd.nl_open_vp = NULL; 1656 nlookup_done(&nd); 1657 1658 VOP_UNLOCK(vp, 0, td); 1659 lf.l_whence = SEEK_SET; 1660 lf.l_start = 0; 1661 lf.l_len = 0; 1662 lf.l_type = F_WRLCK; 1663 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK); 1664 if (error) 1665 goto out2; 1666 1667 /* Don't dump to non-regular files or files with links. */ 1668 if (vp->v_type != VREG || 1669 VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) { 1670 error = EFAULT; 1671 goto out1; 1672 } 1673 1674 VATTR_NULL(&vattr); 1675 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1676 vattr.va_size = 0; 1677 VOP_LEASE(vp, td, cred, LEASE_WRITE); 1678 VOP_SETATTR(vp, &vattr, cred, td); 1679 p->p_acflag |= ACORE; 1680 VOP_UNLOCK(vp, 0, td); 1681 1682 error = p->p_sysent->sv_coredump ? 1683 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1684 1685 out1: 1686 lf.l_type = F_UNLCK; 1687 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); 1688 out2: 1689 error1 = vn_close(vp, FWRITE, td); 1690 if (error == 0) 1691 error = error1; 1692 return (error); 1693 } 1694 1695 /* 1696 * Nonexistent system call-- signal process (may want to handle it). 1697 * Flag error in case process won't see signal immediately (blocked or ignored). 1698 */ 1699 /* ARGSUSED */ 1700 int 1701 nosys(struct nosys_args *args) 1702 { 1703 psignal(curproc, SIGSYS); 1704 return (EINVAL); 1705 } 1706 1707 /* 1708 * Send a SIGIO or SIGURG signal to a process or process group using 1709 * stored credentials rather than those of the current process. 1710 */ 1711 void 1712 pgsigio(struct sigio *sigio, int sig, int checkctty) 1713 { 1714 if (sigio == NULL) 1715 return; 1716 1717 if (sigio->sio_pgid > 0) { 1718 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1719 sigio->sio_proc)) 1720 psignal(sigio->sio_proc, sig); 1721 } else if (sigio->sio_pgid < 0) { 1722 struct proc *p; 1723 1724 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) 1725 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1726 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1727 psignal(p, sig); 1728 } 1729 } 1730 1731 static int 1732 filt_sigattach(struct knote *kn) 1733 { 1734 struct proc *p = curproc; 1735 1736 kn->kn_ptr.p_proc = p; 1737 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1738 1739 /* XXX lock the proc here while adding to the list? */ 1740 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1741 1742 return (0); 1743 } 1744 1745 static void 1746 filt_sigdetach(struct knote *kn) 1747 { 1748 struct proc *p = kn->kn_ptr.p_proc; 1749 1750 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1751 } 1752 1753 /* 1754 * signal knotes are shared with proc knotes, so we apply a mask to 1755 * the hint in order to differentiate them from process hints. This 1756 * could be avoided by using a signal-specific knote list, but probably 1757 * isn't worth the trouble. 1758 */ 1759 static int 1760 filt_signal(struct knote *kn, long hint) 1761 { 1762 if (hint & NOTE_SIGNAL) { 1763 hint &= ~NOTE_SIGNAL; 1764 1765 if (kn->kn_id == hint) 1766 kn->kn_data++; 1767 } 1768 return (kn->kn_data != 0); 1769 } 1770