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 1.57 2006/12/20 18:14:41 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/lock.h> 60 #include <sys/wait.h> 61 #include <sys/ktrace.h> 62 #include <sys/syslog.h> 63 #include <sys/stat.h> 64 #include <sys/sysent.h> 65 #include <sys/sysctl.h> 66 #include <sys/malloc.h> 67 #include <sys/interrupt.h> 68 #include <sys/unistd.h> 69 #include <sys/kern_syscall.h> 70 #include <sys/thread2.h> 71 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 ksignal */ 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 sys_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 sys_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 sys_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 sys_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 sys_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 struct killpg_info { 600 int nfound; 601 int sig; 602 }; 603 604 static int killpg_all_callback(struct proc *p, void *data); 605 606 static int 607 killpg(int sig, int pgid, int all) 608 { 609 struct killpg_info info; 610 struct proc *cp = curproc; 611 struct proc *p; 612 struct pgrp *pgrp; 613 614 info.nfound = 0; 615 info.sig = sig; 616 617 if (all) { 618 /* 619 * broadcast 620 */ 621 allproc_scan(killpg_all_callback, &info); 622 } else { 623 if (pgid == 0) { 624 /* 625 * zero pgid means send to my process group. 626 */ 627 pgrp = cp->p_pgrp; 628 } else { 629 pgrp = pgfind(pgid); 630 if (pgrp == NULL) 631 return (ESRCH); 632 } 633 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 634 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 635 if (p->p_pid <= 1 || 636 (p->p_flag & (P_SYSTEM | P_ZOMBIE)) || 637 !CANSIGNAL(p, sig)) { 638 continue; 639 } 640 ++info.nfound; 641 if (sig) 642 ksignal(p, sig); 643 } 644 lockmgr(&pgrp->pg_lock, LK_RELEASE); 645 } 646 return (info.nfound ? 0 : ESRCH); 647 } 648 649 static int 650 killpg_all_callback(struct proc *p, void *data) 651 { 652 struct killpg_info *info = data; 653 654 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 655 p == curproc || !CANSIGNAL(p, info->sig)) { 656 return (0); 657 } 658 ++info->nfound; 659 if (info->sig) 660 ksignal(p, info->sig); 661 return(0); 662 } 663 664 int 665 kern_kill(int sig, int pid) 666 { 667 struct thread *td = curthread; 668 struct proc *p = td->td_proc; 669 670 if ((u_int)sig > _SIG_MAXSIG) 671 return (EINVAL); 672 if (pid > 0) { 673 /* kill single process */ 674 if ((p = pfind(pid)) == NULL) 675 return (ESRCH); 676 if (!CANSIGNAL(p, sig)) 677 return (EPERM); 678 if (sig) 679 ksignal(p, sig); 680 return (0); 681 } 682 switch (pid) { 683 case -1: /* broadcast signal */ 684 return (killpg(sig, 0, 1)); 685 case 0: /* signal own process group */ 686 return (killpg(sig, 0, 0)); 687 default: /* negative explicit process group */ 688 return (killpg(sig, -pid, 0)); 689 } 690 /* NOTREACHED */ 691 } 692 693 int 694 sys_kill(struct kill_args *uap) 695 { 696 int error; 697 698 error = kern_kill(uap->signum, uap->pid); 699 700 return (error); 701 } 702 703 /* 704 * Send a signal to a process group. 705 */ 706 void 707 gsignal(int pgid, int sig) 708 { 709 struct pgrp *pgrp; 710 711 if (pgid && (pgrp = pgfind(pgid))) 712 pgsignal(pgrp, sig, 0); 713 } 714 715 /* 716 * Send a signal to a process group. If checktty is 1, 717 * limit to members which have a controlling terminal. 718 * 719 * pg_lock interlocks against a fork that might be in progress, to 720 * ensure that the new child process picks up the signal. 721 */ 722 void 723 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 724 { 725 struct proc *p; 726 727 if (pgrp) { 728 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 729 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 730 if (checkctty == 0 || p->p_flag & P_CONTROLT) 731 ksignal(p, sig); 732 } 733 lockmgr(&pgrp->pg_lock, LK_RELEASE); 734 } 735 } 736 737 /* 738 * Send a signal caused by a trap to the current process. 739 * If it will be caught immediately, deliver it with correct code. 740 * Otherwise, post it normally. 741 */ 742 void 743 trapsignal(struct proc *p, int sig, u_long code) 744 { 745 struct sigacts *ps = p->p_sigacts; 746 747 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 748 !SIGISMEMBER(p->p_sigmask, sig)) { 749 p->p_stats->p_ru.ru_nsignals++; 750 #ifdef KTRACE 751 if (KTRPOINT(p->p_thread, KTR_PSIG)) 752 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)], 753 &p->p_sigmask, code); 754 #endif 755 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 756 &p->p_sigmask, code); 757 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 758 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 759 SIGADDSET(p->p_sigmask, sig); 760 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 761 /* 762 * See kern_sigaction() for origin of this code. 763 */ 764 SIGDELSET(p->p_sigcatch, sig); 765 if (sig != SIGCONT && 766 sigprop(sig) & SA_IGNORE) 767 SIGADDSET(p->p_sigignore, sig); 768 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 769 } 770 } else { 771 p->p_code = code; /* XXX for core dump/debugger */ 772 p->p_sig = sig; /* XXX to verify code */ 773 ksignal(p, sig); 774 } 775 } 776 777 /* 778 * Send the signal to the process. If the signal has an action, the action 779 * is usually performed by the target process rather than the caller; we add 780 * the signal to the set of pending signals for the process. 781 * 782 * Exceptions: 783 * o When a stop signal is sent to a sleeping process that takes the 784 * default action, the process is stopped without awakening it. 785 * o SIGCONT restarts stopped processes (or puts them back to sleep) 786 * regardless of the signal action (eg, blocked or ignored). 787 * 788 * Other ignored signals are discarded immediately. 789 */ 790 void 791 ksignal(struct proc *p, int sig) 792 { 793 struct lwp *lp = &p->p_lwp; 794 int prop; 795 sig_t action; 796 797 if (sig > _SIG_MAXSIG || sig <= 0) { 798 printf("ksignal: signal %d\n", sig); 799 panic("ksignal signal number"); 800 } 801 802 crit_enter(); 803 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 804 crit_exit(); 805 806 prop = sigprop(sig); 807 808 /* 809 * If proc is traced, always give parent a chance; 810 * if signal event is tracked by procfs, give *that* 811 * a chance, as well. 812 */ 813 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 814 action = SIG_DFL; 815 } else { 816 /* 817 * If the signal is being ignored, 818 * then we forget about it immediately. 819 * (Note: we don't set SIGCONT in p_sigignore, 820 * and if it is set to SIG_IGN, 821 * action will be SIG_DFL here.) 822 */ 823 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 824 return; 825 if (SIGISMEMBER(p->p_sigmask, sig)) 826 action = SIG_HOLD; 827 else if (SIGISMEMBER(p->p_sigcatch, sig)) 828 action = SIG_CATCH; 829 else 830 action = SIG_DFL; 831 } 832 833 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 834 (p->p_flag & P_TRACED) == 0) { 835 p->p_nice = NZERO; 836 } 837 838 /* 839 * If continuing, clear any pending STOP signals. 840 */ 841 if (prop & SA_CONT) 842 SIG_STOPSIGMASK(p->p_siglist); 843 844 if (prop & SA_STOP) { 845 /* 846 * If sending a tty stop signal to a member of an orphaned 847 * process group, discard the signal here if the action 848 * is default; don't stop the process below if sleeping, 849 * and don't clear any pending SIGCONT. 850 */ 851 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 852 action == SIG_DFL) { 853 return; 854 } 855 SIG_CONTSIGMASK(p->p_siglist); 856 } 857 SIGADDSET(p->p_siglist, sig); 858 859 /* 860 * Defer further processing for signals which are held, 861 * except that stopped processes must be continued by SIGCONT. 862 */ 863 if (action == SIG_HOLD) { 864 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0) 865 return; 866 } 867 868 crit_enter(); 869 870 /* 871 * Process is in tsleep and not stopped 872 */ 873 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) { 874 /* 875 * If the process is sleeping uninterruptibly 876 * we can't interrupt the sleep... the signal will 877 * be noticed when the process returns through 878 * trap() or syscall(). 879 */ 880 if ((p->p_flag & P_SINTR) == 0) 881 goto out; 882 883 /* 884 * If the process is sleeping and traced, make it runnable 885 * so it can discover the signal in issignal() and stop 886 * for the parent. 887 * 888 * If the process is stopped and traced, no further action 889 * is necessary. 890 */ 891 if (p->p_flag & P_TRACED) 892 goto run; 893 894 /* 895 * If the process is sleeping and SA_CONT, and the signal 896 * mode is SIG_DFL, then make the process runnable. 897 * 898 * However, do *NOT* set P_BREAKTSLEEP. We do not want 899 * a SIGCONT to terminate an interruptable tsleep early 900 * and generate a spurious EINTR. 901 */ 902 if ((prop & SA_CONT) && action == SIG_DFL) { 903 SIGDELSET(p->p_siglist, sig); 904 goto run_no_break; 905 } 906 907 /* 908 * If the process is sleeping and receives a STOP signal, 909 * process immediately if possible. All other (caught or 910 * default) signals cause the process to run. 911 */ 912 if (prop & SA_STOP) { 913 if (action != SIG_DFL) 914 goto run; 915 916 /* 917 * If a child holding parent blocked, stopping 918 * could cause deadlock. Take no action at this 919 * time. 920 */ 921 if (p->p_flag & P_PPWAIT) 922 goto out; 923 924 /* 925 * Do not actually try to manipulate the process 926 * while it is sleeping, simply set P_STOPPED to 927 * indicate that it should stop as soon as it safely 928 * can. 929 */ 930 SIGDELSET(p->p_siglist, sig); 931 p->p_flag |= P_STOPPED; 932 p->p_flag &= ~P_WAITED; 933 p->p_xstat = sig; 934 wakeup(p->p_pptr); 935 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 936 ksignal(p->p_pptr, SIGCHLD); 937 goto out; 938 } 939 940 /* 941 * Otherwise the signal can interrupt the sleep. 942 */ 943 goto run; 944 } 945 946 /* 947 * Process is in tsleep and is stopped 948 */ 949 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) { 950 /* 951 * If the process is stopped and is being traced, then no 952 * further action is necessary. 953 */ 954 if (p->p_flag & P_TRACED) 955 goto out; 956 957 /* 958 * If the process is stopped and receives a KILL signal, 959 * make the process runnable. 960 */ 961 if (sig == SIGKILL) 962 goto run; 963 964 /* 965 * If the process is stopped and receives a CONT signal, 966 * then try to make the process runnable again. 967 */ 968 if (prop & SA_CONT) { 969 /* 970 * If SIGCONT is default (or ignored), we continue the 971 * process but don't leave the signal in p_siglist, as 972 * it has no further action. If SIGCONT is held, we 973 * continue the process and leave the signal in 974 * p_siglist. If the process catches SIGCONT, let it 975 * handle the signal itself. 976 */ 977 if (action == SIG_DFL) 978 SIGDELSET(p->p_siglist, sig); 979 if (action == SIG_CATCH) 980 goto run; 981 982 /* 983 * Make runnable but do not break a tsleep unless 984 * some other signal was pending. 985 */ 986 goto run_no_break; 987 } 988 989 /* 990 * If the process is stopped and receives another STOP 991 * signal, we do not need to stop it again. If we did 992 * the shell could get confused. 993 */ 994 if (prop & SA_STOP) { 995 SIGDELSET(p->p_siglist, sig); 996 goto out; 997 } 998 999 /* 1000 * Otherwise the process is sleeping interruptably but 1001 * is stopped, just set the P_BREAKTSLEEP flag and take 1002 * no further action. The next runnable action will wake 1003 * the process up. 1004 */ 1005 p->p_flag |= P_BREAKTSLEEP; 1006 goto out; 1007 } 1008 1009 /* 1010 * Otherwise the process is running 1011 * 1012 * SRUN, SIDL, SZOMB do nothing with the signal, 1013 * other than kicking ourselves if we are running. 1014 * It will either never be noticed, or noticed very soon. 1015 * 1016 * Note that p_thread may be NULL or may not be completely 1017 * initialized if the process is in the SIDL or SZOMB state. 1018 * 1019 * For SMP we may have to forward the request to another cpu. 1020 * YYY the MP lock prevents the target process from moving 1021 * to another cpu, see kern/kern_switch.c 1022 * 1023 * If the target thread is waiting on its message port, 1024 * wakeup the target thread so it can check (or ignore) 1025 * the new signal. YYY needs cleanup. 1026 */ 1027 if (lp == lwkt_preempted_proc()) { 1028 signotify(); 1029 } else if (p->p_stat == SRUN) { 1030 struct thread *td = p->p_thread; 1031 1032 KASSERT(td != NULL, 1033 ("pid %d NULL p_thread stat %d flags %08x", 1034 p->p_pid, p->p_stat, p->p_flag)); 1035 1036 #ifdef SMP 1037 if (td->td_gd != mycpu) 1038 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1039 else 1040 #endif 1041 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1042 lwkt_schedule(td); 1043 } 1044 goto out; 1045 /*NOTREACHED*/ 1046 run: 1047 /* 1048 * Make runnable and break out of any tsleep as well. 1049 */ 1050 p->p_flag |= P_BREAKTSLEEP; 1051 run_no_break: 1052 setrunnable(p); 1053 out: 1054 crit_exit(); 1055 } 1056 1057 #ifdef SMP 1058 1059 /* 1060 * This function is called via an IPI. We will be in a critical section but 1061 * the MP lock will NOT be held. Also note that by the time the ipi message 1062 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1063 */ 1064 static void 1065 signotify_remote(void *arg) 1066 { 1067 struct lwp *lp = arg; 1068 1069 if (lp == lwkt_preempted_proc()) { 1070 signotify(); 1071 } else { 1072 struct thread *td = lp->lwp_thread; 1073 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1074 lwkt_schedule(td); 1075 } 1076 } 1077 1078 #endif 1079 1080 static int 1081 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1082 { 1083 sigset_t savedmask, set; 1084 struct proc *p = curproc; 1085 int error, sig, hz, timevalid = 0; 1086 struct timespec rts, ets, ts; 1087 struct timeval tv; 1088 1089 error = 0; 1090 sig = 0; 1091 SIG_CANTMASK(waitset); 1092 savedmask = p->p_sigmask; 1093 1094 if (timeout) { 1095 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1096 timeout->tv_nsec < 1000000000) { 1097 timevalid = 1; 1098 getnanouptime(&rts); 1099 ets = rts; 1100 timespecadd(&ets, timeout); 1101 } 1102 } 1103 1104 for (;;) { 1105 set = p->p_siglist; 1106 SIGSETAND(set, waitset); 1107 if ((sig = sig_ffs(&set)) != 0) { 1108 SIGFILLSET(p->p_sigmask); 1109 SIGDELSET(p->p_sigmask, sig); 1110 SIG_CANTMASK(p->p_sigmask); 1111 sig = issignal(p); 1112 /* 1113 * It may be a STOP signal, in the case, issignal 1114 * returns 0, because we may stop there, and new 1115 * signal can come in, we should restart if we got 1116 * nothing. 1117 */ 1118 if (sig == 0) 1119 continue; 1120 else 1121 break; 1122 } 1123 1124 /* 1125 * Previous checking got nothing, and we retried but still 1126 * got nothing, we should return the error status. 1127 */ 1128 if (error) 1129 break; 1130 1131 /* 1132 * POSIX says this must be checked after looking for pending 1133 * signals. 1134 */ 1135 if (timeout) { 1136 if (!timevalid) { 1137 error = EINVAL; 1138 break; 1139 } 1140 getnanouptime(&rts); 1141 if (timespeccmp(&rts, &ets, >=)) { 1142 error = EAGAIN; 1143 break; 1144 } 1145 ts = ets; 1146 timespecsub(&ts, &rts); 1147 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1148 hz = tvtohz_high(&tv); 1149 } else 1150 hz = 0; 1151 1152 p->p_sigmask = savedmask; 1153 SIGSETNAND(p->p_sigmask, waitset); 1154 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1155 if (timeout) { 1156 if (error == ERESTART) { 1157 /* can not restart a timeout wait. */ 1158 error = EINTR; 1159 } else if (error == EAGAIN) { 1160 /* will calculate timeout by ourself. */ 1161 error = 0; 1162 } 1163 } 1164 /* Retry ... */ 1165 } 1166 1167 p->p_sigmask = savedmask; 1168 if (sig) { 1169 error = 0; 1170 bzero(info, sizeof(*info)); 1171 info->si_signo = sig; 1172 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1173 1174 if (sig == SIGKILL) 1175 sigexit(p, sig); 1176 } 1177 return (error); 1178 } 1179 1180 int 1181 sys_sigtimedwait(struct sigtimedwait_args *uap) 1182 { 1183 struct timespec ts; 1184 struct timespec *timeout; 1185 sigset_t set; 1186 siginfo_t info; 1187 int error; 1188 1189 if (uap->timeout) { 1190 error = copyin(uap->timeout, &ts, sizeof(ts)); 1191 if (error) 1192 return (error); 1193 timeout = &ts; 1194 } else { 1195 timeout = NULL; 1196 } 1197 error = copyin(uap->set, &set, sizeof(set)); 1198 if (error) 1199 return (error); 1200 error = kern_sigtimedwait(set, &info, timeout); 1201 if (error) 1202 return (error); 1203 if (uap->info) 1204 error = copyout(&info, uap->info, sizeof(info)); 1205 /* Repost if we got an error. */ 1206 if (error) 1207 ksignal(curproc, info.si_signo); 1208 else 1209 uap->sysmsg_result = info.si_signo; 1210 return (error); 1211 } 1212 1213 int 1214 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1215 { 1216 siginfo_t info; 1217 sigset_t set; 1218 int error; 1219 1220 error = copyin(uap->set, &set, sizeof(set)); 1221 if (error) 1222 return (error); 1223 error = kern_sigtimedwait(set, &info, NULL); 1224 if (error) 1225 return (error); 1226 if (uap->info) 1227 error = copyout(&info, uap->info, sizeof(info)); 1228 /* Repost if we got an error. */ 1229 if (error) 1230 ksignal(curproc, info.si_signo); 1231 else 1232 uap->sysmsg_result = info.si_signo; 1233 return (error); 1234 } 1235 1236 /* 1237 * If the current process has received a signal that would interrupt a 1238 * system call, return EINTR or ERESTART as appropriate. 1239 */ 1240 int 1241 iscaught(struct proc *p) 1242 { 1243 int sig; 1244 1245 if (p) { 1246 if ((sig = CURSIG(p)) != 0) { 1247 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1248 return (EINTR); 1249 return (ERESTART); 1250 } 1251 } 1252 return(EWOULDBLOCK); 1253 } 1254 1255 /* 1256 * If the current process has received a signal (should be caught or cause 1257 * termination, should interrupt current syscall), return the signal number. 1258 * Stop signals with default action are processed immediately, then cleared; 1259 * they aren't returned. This is checked after each entry to the system for 1260 * a syscall or trap (though this can usually be done without calling issignal 1261 * by checking the pending signal masks in the CURSIG macro.) The normal call 1262 * sequence is 1263 * 1264 * This routine is called via CURSIG/__cursig and the MP lock might not be 1265 * held. Obtain the MP lock for the duration of the operation. 1266 * 1267 * while (sig = CURSIG(curproc)) 1268 * postsig(sig); 1269 */ 1270 int 1271 issignal(struct proc *p) 1272 { 1273 sigset_t mask; 1274 int sig, prop; 1275 1276 get_mplock(); 1277 for (;;) { 1278 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1279 1280 mask = p->p_siglist; 1281 SIGSETNAND(mask, p->p_sigmask); 1282 if (p->p_flag & P_PPWAIT) 1283 SIG_STOPSIGMASK(mask); 1284 if (!SIGNOTEMPTY(mask)) { /* no signal to send */ 1285 rel_mplock(); 1286 return (0); 1287 } 1288 sig = sig_ffs(&mask); 1289 1290 STOPEVENT(p, S_SIG, sig); 1291 1292 /* 1293 * We should see pending but ignored signals 1294 * only if P_TRACED was on when they were posted. 1295 */ 1296 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1297 SIGDELSET(p->p_siglist, sig); 1298 continue; 1299 } 1300 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1301 /* 1302 * If traced, always stop, and stay stopped until 1303 * released by the parent. 1304 * 1305 * NOTE: P_STOPPED may get cleared during the loop, 1306 * but we do not re-notify the parent if we have 1307 * to loop several times waiting for the parent 1308 * to let us continue. 1309 */ 1310 p->p_xstat = sig; 1311 p->p_flag |= P_STOPPED; 1312 p->p_flag &= ~P_WAITED; 1313 ksignal(p->p_pptr, SIGCHLD); 1314 do { 1315 tstop(p); 1316 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1317 p->p_flag &= ~P_STOPPED; 1318 1319 /* 1320 * If parent wants us to take the signal, 1321 * then it will leave it in p->p_xstat; 1322 * otherwise we just look for signals again. 1323 */ 1324 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1325 sig = p->p_xstat; 1326 if (sig == 0) 1327 continue; 1328 1329 /* 1330 * Put the new signal into p_siglist. If the 1331 * signal is being masked, look for other signals. 1332 */ 1333 SIGADDSET(p->p_siglist, sig); 1334 if (SIGISMEMBER(p->p_sigmask, sig)) 1335 continue; 1336 1337 /* 1338 * If the traced bit got turned off, go back up 1339 * to the top to rescan signals. This ensures 1340 * that p_sig* and ps_sigact are consistent. 1341 */ 1342 if ((p->p_flag & P_TRACED) == 0) 1343 continue; 1344 } 1345 1346 prop = sigprop(sig); 1347 1348 /* 1349 * Decide whether the signal should be returned. 1350 * Return the signal's number, or fall through 1351 * to clear it from the pending mask. 1352 */ 1353 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1354 case (int)SIG_DFL: 1355 /* 1356 * Don't take default actions on system processes. 1357 */ 1358 if (p->p_pid <= 1) { 1359 #ifdef DIAGNOSTIC 1360 /* 1361 * Are you sure you want to ignore SIGSEGV 1362 * in init? XXX 1363 */ 1364 printf("Process (pid %lu) got signal %d\n", 1365 (u_long)p->p_pid, sig); 1366 #endif 1367 break; /* == ignore */ 1368 } 1369 1370 /* 1371 * Handle the in-kernel checkpoint action 1372 */ 1373 if (prop & SA_CKPT) { 1374 checkpoint_signal_handler(p); 1375 break; 1376 } 1377 1378 /* 1379 * If there is a pending stop signal to process 1380 * with default action, stop here, 1381 * then clear the signal. However, 1382 * if process is member of an orphaned 1383 * process group, ignore tty stop signals. 1384 */ 1385 if (prop & SA_STOP) { 1386 if (p->p_flag & P_TRACED || 1387 (p->p_pgrp->pg_jobc == 0 && 1388 prop & SA_TTYSTOP)) 1389 break; /* == ignore */ 1390 p->p_xstat = sig; 1391 p->p_flag |= P_STOPPED; 1392 p->p_flag &= ~P_WAITED; 1393 1394 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1395 ksignal(p->p_pptr, SIGCHLD); 1396 while (p->p_flag & P_STOPPED) { 1397 tstop(p); 1398 } 1399 break; 1400 } else if (prop & SA_IGNORE) { 1401 /* 1402 * Except for SIGCONT, shouldn't get here. 1403 * Default action is to ignore; drop it. 1404 */ 1405 break; /* == ignore */ 1406 } else { 1407 rel_mplock(); 1408 return (sig); 1409 } 1410 1411 /*NOTREACHED*/ 1412 1413 case (int)SIG_IGN: 1414 /* 1415 * Masking above should prevent us ever trying 1416 * to take action on an ignored signal other 1417 * than SIGCONT, unless process is traced. 1418 */ 1419 if ((prop & SA_CONT) == 0 && 1420 (p->p_flag & P_TRACED) == 0) 1421 printf("issignal\n"); 1422 break; /* == ignore */ 1423 1424 default: 1425 /* 1426 * This signal has an action, let 1427 * postsig() process it. 1428 */ 1429 rel_mplock(); 1430 return (sig); 1431 } 1432 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1433 } 1434 /* NOTREACHED */ 1435 } 1436 1437 /* 1438 * Take the action for the specified signal 1439 * from the current set of pending signals. 1440 */ 1441 void 1442 postsig(int sig) 1443 { 1444 struct thread *td = curthread; 1445 struct proc *p = td->td_proc; 1446 struct sigacts *ps = p->p_sigacts; 1447 sig_t action; 1448 sigset_t returnmask; 1449 int code; 1450 1451 KASSERT(sig != 0, ("postsig")); 1452 1453 SIGDELSET(p->p_siglist, sig); 1454 action = ps->ps_sigact[_SIG_IDX(sig)]; 1455 #ifdef KTRACE 1456 if (KTRPOINT(td, KTR_PSIG)) 1457 ktrpsig(p, sig, action, p->p_flag & P_OLDMASK ? 1458 &p->p_oldsigmask : &p->p_sigmask, 0); 1459 #endif 1460 STOPEVENT(p, S_SIG, sig); 1461 1462 if (action == SIG_DFL) { 1463 /* 1464 * Default action, where the default is to kill 1465 * the process. (Other cases were ignored above.) 1466 */ 1467 sigexit(p, sig); 1468 /* NOTREACHED */ 1469 } else { 1470 /* 1471 * If we get here, the signal must be caught. 1472 */ 1473 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), 1474 ("postsig action")); 1475 /* 1476 * Set the new mask value and also defer further 1477 * occurrences of this signal. 1478 * 1479 * Special case: user has done a sigsuspend. Here the 1480 * current mask is not of interest, but rather the 1481 * mask from before the sigsuspend is what we want 1482 * restored after the signal processing is completed. 1483 */ 1484 crit_enter(); 1485 if (p->p_flag & P_OLDMASK) { 1486 returnmask = p->p_oldsigmask; 1487 p->p_flag &= ~P_OLDMASK; 1488 } else { 1489 returnmask = p->p_sigmask; 1490 } 1491 1492 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1493 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1494 SIGADDSET(p->p_sigmask, sig); 1495 1496 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1497 /* 1498 * See kern_sigaction() for origin of this code. 1499 */ 1500 SIGDELSET(p->p_sigcatch, sig); 1501 if (sig != SIGCONT && 1502 sigprop(sig) & SA_IGNORE) 1503 SIGADDSET(p->p_sigignore, sig); 1504 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1505 } 1506 crit_exit(); 1507 p->p_stats->p_ru.ru_nsignals++; 1508 if (p->p_sig != sig) { 1509 code = 0; 1510 } else { 1511 code = p->p_code; 1512 p->p_code = 0; 1513 p->p_sig = 0; 1514 } 1515 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1516 } 1517 } 1518 1519 /* 1520 * Kill the current process for stated reason. 1521 */ 1522 void 1523 killproc(struct proc *p, char *why) 1524 { 1525 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, 1526 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1527 ksignal(p, SIGKILL); 1528 } 1529 1530 /* 1531 * Force the current process to exit with the specified signal, dumping core 1532 * if appropriate. We bypass the normal tests for masked and caught signals, 1533 * allowing unrecoverable failures to terminate the process without changing 1534 * signal state. Mark the accounting record with the signal termination. 1535 * If dumping core, save the signal number for the debugger. Calls exit and 1536 * does not return. 1537 */ 1538 void 1539 sigexit(struct proc *p, int sig) 1540 { 1541 p->p_acflag |= AXSIG; 1542 if (sigprop(sig) & SA_CORE) { 1543 p->p_sig = sig; 1544 /* 1545 * Log signals which would cause core dumps 1546 * (Log as LOG_INFO to appease those who don't want 1547 * these messages.) 1548 * XXX : Todo, as well as euid, write out ruid too 1549 */ 1550 if (coredump(p) == 0) 1551 sig |= WCOREFLAG; 1552 if (kern_logsigexit) 1553 log(LOG_INFO, 1554 "pid %d (%s), uid %d: exited on signal %d%s\n", 1555 p->p_pid, p->p_comm, 1556 p->p_ucred ? p->p_ucred->cr_uid : -1, 1557 sig &~ WCOREFLAG, 1558 sig & WCOREFLAG ? " (core dumped)" : ""); 1559 } 1560 exit1(W_EXITCODE(0, sig)); 1561 /* NOTREACHED */ 1562 } 1563 1564 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1565 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1566 sizeof(corefilename), "process corefile name format string"); 1567 1568 /* 1569 * expand_name(name, uid, pid) 1570 * Expand the name described in corefilename, using name, uid, and pid. 1571 * corefilename is a printf-like string, with three format specifiers: 1572 * %N name of process ("name") 1573 * %P process id (pid) 1574 * %U user id (uid) 1575 * For example, "%N.core" is the default; they can be disabled completely 1576 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1577 * This is controlled by the sysctl variable kern.corefile (see above). 1578 */ 1579 1580 static char * 1581 expand_name(const char *name, uid_t uid, pid_t pid) 1582 { 1583 char *temp; 1584 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1585 int i, n; 1586 char *format = corefilename; 1587 size_t namelen; 1588 1589 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1590 if (temp == NULL) 1591 return NULL; 1592 namelen = strlen(name); 1593 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1594 int l; 1595 switch (format[i]) { 1596 case '%': /* Format character */ 1597 i++; 1598 switch (format[i]) { 1599 case '%': 1600 temp[n++] = '%'; 1601 break; 1602 case 'N': /* process name */ 1603 if ((n + namelen) > MAXPATHLEN) { 1604 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1605 pid, name, uid, temp, name); 1606 kfree(temp, M_TEMP); 1607 return NULL; 1608 } 1609 memcpy(temp+n, name, namelen); 1610 n += namelen; 1611 break; 1612 case 'P': /* process id */ 1613 l = ksprintf(buf, "%u", pid); 1614 if ((n + l) > MAXPATHLEN) { 1615 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1616 pid, name, uid, temp, name); 1617 kfree(temp, M_TEMP); 1618 return NULL; 1619 } 1620 memcpy(temp+n, buf, l); 1621 n += l; 1622 break; 1623 case 'U': /* user id */ 1624 l = ksprintf(buf, "%u", uid); 1625 if ((n + l) > MAXPATHLEN) { 1626 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1627 pid, name, uid, temp, name); 1628 kfree(temp, M_TEMP); 1629 return NULL; 1630 } 1631 memcpy(temp+n, buf, l); 1632 n += l; 1633 break; 1634 default: 1635 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1636 } 1637 break; 1638 default: 1639 temp[n++] = format[i]; 1640 } 1641 } 1642 temp[n] = '\0'; 1643 return temp; 1644 } 1645 1646 /* 1647 * Dump a process' core. The main routine does some 1648 * policy checking, and creates the name of the coredump; 1649 * then it passes on a vnode and a size limit to the process-specific 1650 * coredump routine if there is one; if there _is not_ one, it returns 1651 * ENOSYS; otherwise it returns the error from the process-specific routine. 1652 */ 1653 1654 static int 1655 coredump(struct proc *p) 1656 { 1657 struct vnode *vp; 1658 struct ucred *cred = p->p_ucred; 1659 struct flock lf; 1660 struct nlookupdata nd; 1661 struct vattr vattr; 1662 int error, error1; 1663 char *name; /* name of corefile */ 1664 off_t limit; 1665 1666 STOPEVENT(p, S_CORE, 0); 1667 1668 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1669 return (EFAULT); 1670 1671 /* 1672 * Note that the bulk of limit checking is done after 1673 * the corefile is created. The exception is if the limit 1674 * for corefiles is 0, in which case we don't bother 1675 * creating the corefile at all. This layout means that 1676 * a corefile is truncated instead of not being created, 1677 * if it is larger than the limit. 1678 */ 1679 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1680 if (limit == 0) 1681 return EFBIG; 1682 1683 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1684 if (name == NULL) 1685 return (EINVAL); 1686 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1687 if (error == 0) 1688 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1689 kfree(name, M_TEMP); 1690 if (error) { 1691 nlookup_done(&nd); 1692 return (error); 1693 } 1694 vp = nd.nl_open_vp; 1695 nd.nl_open_vp = NULL; 1696 nlookup_done(&nd); 1697 1698 vn_unlock(vp); 1699 lf.l_whence = SEEK_SET; 1700 lf.l_start = 0; 1701 lf.l_len = 0; 1702 lf.l_type = F_WRLCK; 1703 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 1704 if (error) 1705 goto out2; 1706 1707 /* Don't dump to non-regular files or files with links. */ 1708 if (vp->v_type != VREG || 1709 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 1710 error = EFAULT; 1711 goto out1; 1712 } 1713 1714 VATTR_NULL(&vattr); 1715 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1716 vattr.va_size = 0; 1717 VOP_SETATTR(vp, &vattr, cred); 1718 p->p_acflag |= ACORE; 1719 vn_unlock(vp); 1720 1721 error = p->p_sysent->sv_coredump ? 1722 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1723 1724 out1: 1725 lf.l_type = F_UNLCK; 1726 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 1727 out2: 1728 error1 = vn_close(vp, FWRITE); 1729 if (error == 0) 1730 error = error1; 1731 return (error); 1732 } 1733 1734 /* 1735 * Nonexistent system call-- signal process (may want to handle it). 1736 * Flag error in case process won't see signal immediately (blocked or ignored). 1737 */ 1738 /* ARGSUSED */ 1739 int 1740 sys_nosys(struct nosys_args *args) 1741 { 1742 ksignal(curproc, SIGSYS); 1743 return (EINVAL); 1744 } 1745 1746 /* 1747 * Send a SIGIO or SIGURG signal to a process or process group using 1748 * stored credentials rather than those of the current process. 1749 */ 1750 void 1751 pgsigio(struct sigio *sigio, int sig, int checkctty) 1752 { 1753 if (sigio == NULL) 1754 return; 1755 1756 if (sigio->sio_pgid > 0) { 1757 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1758 sigio->sio_proc)) 1759 ksignal(sigio->sio_proc, sig); 1760 } else if (sigio->sio_pgid < 0) { 1761 struct proc *p; 1762 1763 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 1764 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 1765 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1766 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1767 ksignal(p, sig); 1768 } 1769 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 1770 } 1771 } 1772 1773 static int 1774 filt_sigattach(struct knote *kn) 1775 { 1776 struct proc *p = curproc; 1777 1778 kn->kn_ptr.p_proc = p; 1779 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1780 1781 /* XXX lock the proc here while adding to the list? */ 1782 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1783 1784 return (0); 1785 } 1786 1787 static void 1788 filt_sigdetach(struct knote *kn) 1789 { 1790 struct proc *p = kn->kn_ptr.p_proc; 1791 1792 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1793 } 1794 1795 /* 1796 * signal knotes are shared with proc knotes, so we apply a mask to 1797 * the hint in order to differentiate them from process hints. This 1798 * could be avoided by using a signal-specific knote list, but probably 1799 * isn't worth the trouble. 1800 */ 1801 static int 1802 filt_signal(struct knote *kn, long hint) 1803 { 1804 if (hint & NOTE_SIGNAL) { 1805 hint &= ~NOTE_SIGNAL; 1806 1807 if (kn->kn_id == hint) 1808 kn->kn_data++; 1809 } 1810 return (kn->kn_data != 0); 1811 } 1812