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 1.55 2006/10/10 15:40:46 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/unistd.h> 68 #include <sys/kern_syscall.h> 69 #include <sys/thread2.h> 70 71 72 #include <machine/ipl.h> 73 #include <machine/cpu.h> 74 #include <machine/smp.h> 75 76 static int coredump(struct proc *); 77 static char *expand_name(const char *, uid_t, pid_t); 78 static int killpg(int sig, int pgid, int all); 79 static int sig_ffs(sigset_t *set); 80 static int sigprop(int sig); 81 #ifdef SMP 82 static void signotify_remote(void *arg); 83 #endif 84 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 85 struct timespec *timeout); 86 87 static int filt_sigattach(struct knote *kn); 88 static void filt_sigdetach(struct knote *kn); 89 static int filt_signal(struct knote *kn, long hint); 90 91 struct filterops sig_filtops = 92 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 93 94 static int kern_logsigexit = 1; 95 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 96 &kern_logsigexit, 0, 97 "Log processes quitting on abnormal signals to syslog(3)"); 98 99 /* 100 * Can process p, with pcred pc, send the signal sig to process q? 101 */ 102 #define CANSIGNAL(q, sig) \ 103 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 105 106 /* 107 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 108 */ 109 #define CANSIGIO(ruid, uc, q) \ 110 ((uc)->cr_uid == 0 || \ 111 (ruid) == (q)->p_ucred->cr_ruid || \ 112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 113 (ruid) == (q)->p_ucred->cr_uid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_uid) 115 116 int sugid_coredump; 117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 119 120 static int do_coredump = 1; 121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 122 &do_coredump, 0, "Enable/Disable coredumps"); 123 124 /* 125 * Signal properties and actions. 126 * The array below categorizes the signals and their default actions 127 * according to the following properties: 128 */ 129 #define SA_KILL 0x01 /* terminates process by default */ 130 #define SA_CORE 0x02 /* ditto and coredumps */ 131 #define SA_STOP 0x04 /* suspend process */ 132 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 133 #define SA_IGNORE 0x10 /* ignore by default */ 134 #define SA_CONT 0x20 /* continue if suspended */ 135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 136 #define SA_CKPT 0x80 /* checkpoint process */ 137 138 139 static int sigproptbl[NSIG] = { 140 SA_KILL, /* SIGHUP */ 141 SA_KILL, /* SIGINT */ 142 SA_KILL|SA_CORE, /* SIGQUIT */ 143 SA_KILL|SA_CORE, /* SIGILL */ 144 SA_KILL|SA_CORE, /* SIGTRAP */ 145 SA_KILL|SA_CORE, /* SIGABRT */ 146 SA_KILL|SA_CORE, /* SIGEMT */ 147 SA_KILL|SA_CORE, /* SIGFPE */ 148 SA_KILL, /* SIGKILL */ 149 SA_KILL|SA_CORE, /* SIGBUS */ 150 SA_KILL|SA_CORE, /* SIGSEGV */ 151 SA_KILL|SA_CORE, /* SIGSYS */ 152 SA_KILL, /* SIGPIPE */ 153 SA_KILL, /* SIGALRM */ 154 SA_KILL, /* SIGTERM */ 155 SA_IGNORE, /* SIGURG */ 156 SA_STOP, /* SIGSTOP */ 157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 158 SA_IGNORE|SA_CONT, /* SIGCONT */ 159 SA_IGNORE, /* SIGCHLD */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 162 SA_IGNORE, /* SIGIO */ 163 SA_KILL, /* SIGXCPU */ 164 SA_KILL, /* SIGXFSZ */ 165 SA_KILL, /* SIGVTALRM */ 166 SA_KILL, /* SIGPROF */ 167 SA_IGNORE, /* SIGWINCH */ 168 SA_IGNORE, /* SIGINFO */ 169 SA_KILL, /* SIGUSR1 */ 170 SA_KILL, /* SIGUSR2 */ 171 SA_IGNORE, /* SIGTHR */ 172 SA_CKPT, /* SIGCKPT */ 173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 205 }; 206 207 static __inline int 208 sigprop(int sig) 209 { 210 211 if (sig > 0 && sig < NSIG) 212 return (sigproptbl[_SIG_IDX(sig)]); 213 return (0); 214 } 215 216 static __inline int 217 sig_ffs(sigset_t *set) 218 { 219 int i; 220 221 for (i = 0; i < _SIG_WORDS; i++) 222 if (set->__bits[i]) 223 return (ffs(set->__bits[i]) + (i * 32)); 224 return (0); 225 } 226 227 int 228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 229 { 230 struct thread *td = curthread; 231 struct proc *p = td->td_proc; 232 struct sigacts *ps = p->p_sigacts; 233 234 if (sig <= 0 || sig > _SIG_MAXSIG) 235 return (EINVAL); 236 237 if (oact) { 238 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 239 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 240 oact->sa_flags = 0; 241 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 242 oact->sa_flags |= SA_ONSTACK; 243 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 244 oact->sa_flags |= SA_RESTART; 245 if (SIGISMEMBER(ps->ps_sigreset, sig)) 246 oact->sa_flags |= SA_RESETHAND; 247 if (SIGISMEMBER(ps->ps_signodefer, sig)) 248 oact->sa_flags |= SA_NODEFER; 249 if (SIGISMEMBER(ps->ps_siginfo, sig)) 250 oact->sa_flags |= SA_SIGINFO; 251 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) 252 oact->sa_flags |= SA_NOCLDSTOP; 253 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) 254 oact->sa_flags |= SA_NOCLDWAIT; 255 } 256 if (act) { 257 if ((sig == SIGKILL || sig == SIGSTOP) && 258 act->sa_handler != SIG_DFL) 259 return (EINVAL); 260 261 /* 262 * Change setting atomically. 263 */ 264 crit_enter(); 265 266 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 267 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 268 if (act->sa_flags & SA_SIGINFO) { 269 ps->ps_sigact[_SIG_IDX(sig)] = 270 (__sighandler_t *)act->sa_sigaction; 271 SIGADDSET(ps->ps_siginfo, sig); 272 } else { 273 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 274 SIGDELSET(ps->ps_siginfo, sig); 275 } 276 if (!(act->sa_flags & SA_RESTART)) 277 SIGADDSET(ps->ps_sigintr, sig); 278 else 279 SIGDELSET(ps->ps_sigintr, sig); 280 if (act->sa_flags & SA_ONSTACK) 281 SIGADDSET(ps->ps_sigonstack, sig); 282 else 283 SIGDELSET(ps->ps_sigonstack, sig); 284 if (act->sa_flags & SA_RESETHAND) 285 SIGADDSET(ps->ps_sigreset, sig); 286 else 287 SIGDELSET(ps->ps_sigreset, sig); 288 if (act->sa_flags & SA_NODEFER) 289 SIGADDSET(ps->ps_signodefer, sig); 290 else 291 SIGDELSET(ps->ps_signodefer, sig); 292 if (sig == SIGCHLD) { 293 if (act->sa_flags & SA_NOCLDSTOP) 294 p->p_procsig->ps_flag |= PS_NOCLDSTOP; 295 else 296 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; 297 if (act->sa_flags & SA_NOCLDWAIT) { 298 /* 299 * Paranoia: since SA_NOCLDWAIT is implemented 300 * by reparenting the dying child to PID 1 (and 301 * trust it to reap the zombie), PID 1 itself 302 * is forbidden to set SA_NOCLDWAIT. 303 */ 304 if (p->p_pid == 1) 305 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 306 else 307 p->p_procsig->ps_flag |= PS_NOCLDWAIT; 308 } else { 309 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 310 } 311 } 312 /* 313 * Set bit in p_sigignore for signals that are set to SIG_IGN, 314 * and for signals set to SIG_DFL where the default is to 315 * ignore. However, don't put SIGCONT in p_sigignore, as we 316 * have to restart the process. 317 */ 318 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 319 (sigprop(sig) & SA_IGNORE && 320 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 321 /* never to be seen again */ 322 SIGDELSET(p->p_siglist, sig); 323 if (sig != SIGCONT) 324 /* easier in ksignal */ 325 SIGADDSET(p->p_sigignore, sig); 326 SIGDELSET(p->p_sigcatch, sig); 327 } else { 328 SIGDELSET(p->p_sigignore, sig); 329 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 330 SIGDELSET(p->p_sigcatch, sig); 331 else 332 SIGADDSET(p->p_sigcatch, sig); 333 } 334 335 crit_exit(); 336 } 337 return (0); 338 } 339 340 int 341 sys_sigaction(struct sigaction_args *uap) 342 { 343 struct sigaction act, oact; 344 struct sigaction *actp, *oactp; 345 int error; 346 347 actp = (uap->act != NULL) ? &act : NULL; 348 oactp = (uap->oact != NULL) ? &oact : NULL; 349 if (actp) { 350 error = copyin(uap->act, actp, sizeof(act)); 351 if (error) 352 return (error); 353 } 354 error = kern_sigaction(uap->sig, actp, oactp); 355 if (oactp && !error) { 356 error = copyout(oactp, uap->oact, sizeof(oact)); 357 } 358 return (error); 359 } 360 361 /* 362 * Initialize signal state for process 0; 363 * set to ignore signals that are ignored by default. 364 */ 365 void 366 siginit(struct proc *p) 367 { 368 int i; 369 370 for (i = 1; i <= NSIG; i++) 371 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 372 SIGADDSET(p->p_sigignore, i); 373 } 374 375 /* 376 * Reset signals for an exec of the specified process. 377 */ 378 void 379 execsigs(struct proc *p) 380 { 381 struct sigacts *ps = p->p_sigacts; 382 int sig; 383 384 /* 385 * Reset caught signals. Held signals remain held 386 * through p_sigmask (unless they were caught, 387 * and are now ignored by default). 388 */ 389 while (SIGNOTEMPTY(p->p_sigcatch)) { 390 sig = sig_ffs(&p->p_sigcatch); 391 SIGDELSET(p->p_sigcatch, sig); 392 if (sigprop(sig) & SA_IGNORE) { 393 if (sig != SIGCONT) 394 SIGADDSET(p->p_sigignore, sig); 395 SIGDELSET(p->p_siglist, sig); 396 } 397 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 398 } 399 /* 400 * Reset stack state to the user stack. 401 * Clear set of signals caught on the signal stack. 402 */ 403 p->p_sigstk.ss_flags = SS_DISABLE; 404 p->p_sigstk.ss_size = 0; 405 p->p_sigstk.ss_sp = 0; 406 p->p_flag &= ~P_ALTSTACK; 407 /* 408 * Reset no zombies if child dies flag as Solaris does. 409 */ 410 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 411 } 412 413 /* 414 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 415 * 416 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 417 * p == curproc. 418 */ 419 int 420 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 421 { 422 struct thread *td = curthread; 423 struct proc *p = td->td_proc; 424 int error; 425 426 if (oset != NULL) 427 *oset = p->p_sigmask; 428 429 error = 0; 430 if (set != NULL) { 431 switch (how) { 432 case SIG_BLOCK: 433 SIG_CANTMASK(*set); 434 SIGSETOR(p->p_sigmask, *set); 435 break; 436 case SIG_UNBLOCK: 437 SIGSETNAND(p->p_sigmask, *set); 438 break; 439 case SIG_SETMASK: 440 SIG_CANTMASK(*set); 441 p->p_sigmask = *set; 442 break; 443 default: 444 error = EINVAL; 445 break; 446 } 447 } 448 return (error); 449 } 450 451 /* 452 * sigprocmask() - MP SAFE 453 */ 454 int 455 sys_sigprocmask(struct sigprocmask_args *uap) 456 { 457 sigset_t set, oset; 458 sigset_t *setp, *osetp; 459 int error; 460 461 setp = (uap->set != NULL) ? &set : NULL; 462 osetp = (uap->oset != NULL) ? &oset : NULL; 463 if (setp) { 464 error = copyin(uap->set, setp, sizeof(set)); 465 if (error) 466 return (error); 467 } 468 error = kern_sigprocmask(uap->how, setp, osetp); 469 if (osetp && !error) { 470 error = copyout(osetp, uap->oset, sizeof(oset)); 471 } 472 return (error); 473 } 474 475 int 476 kern_sigpending(struct __sigset *set) 477 { 478 struct thread *td = curthread; 479 struct proc *p = td->td_proc; 480 481 *set = p->p_siglist; 482 483 return (0); 484 } 485 486 int 487 sys_sigpending(struct sigpending_args *uap) 488 { 489 sigset_t set; 490 int error; 491 492 error = kern_sigpending(&set); 493 494 if (error == 0) 495 error = copyout(&set, uap->set, sizeof(set)); 496 return (error); 497 } 498 499 /* 500 * Suspend process until signal, providing mask to be set 501 * in the meantime. 502 */ 503 int 504 kern_sigsuspend(struct __sigset *set) 505 { 506 struct thread *td = curthread; 507 struct proc *p = td->td_proc; 508 struct sigacts *ps = p->p_sigacts; 509 510 /* 511 * When returning from sigsuspend, we want 512 * the old mask to be restored after the 513 * signal handler has finished. Thus, we 514 * save it here and mark the sigacts structure 515 * to indicate this. 516 */ 517 p->p_oldsigmask = p->p_sigmask; 518 p->p_flag |= P_OLDMASK; 519 520 SIG_CANTMASK(*set); 521 p->p_sigmask = *set; 522 while (tsleep(ps, PCATCH, "pause", 0) == 0) 523 /* void */; 524 /* always return EINTR rather than ERESTART... */ 525 return (EINTR); 526 } 527 528 /* 529 * Note nonstandard calling convention: libc stub passes mask, not 530 * pointer, to save a copyin. 531 */ 532 int 533 sys_sigsuspend(struct sigsuspend_args *uap) 534 { 535 sigset_t mask; 536 int error; 537 538 error = copyin(uap->sigmask, &mask, sizeof(mask)); 539 if (error) 540 return (error); 541 542 error = kern_sigsuspend(&mask); 543 544 return (error); 545 } 546 547 int 548 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 549 { 550 struct thread *td = curthread; 551 struct proc *p = td->td_proc; 552 553 if ((p->p_flag & P_ALTSTACK) == 0) 554 p->p_sigstk.ss_flags |= SS_DISABLE; 555 556 if (oss) 557 *oss = p->p_sigstk; 558 559 if (ss) { 560 if (ss->ss_flags & SS_DISABLE) { 561 if (p->p_sigstk.ss_flags & SS_ONSTACK) 562 return (EINVAL); 563 p->p_flag &= ~P_ALTSTACK; 564 p->p_sigstk.ss_flags = ss->ss_flags; 565 } else { 566 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 567 return (ENOMEM); 568 p->p_flag |= P_ALTSTACK; 569 p->p_sigstk = *ss; 570 } 571 } 572 573 return (0); 574 } 575 576 int 577 sys_sigaltstack(struct sigaltstack_args *uap) 578 { 579 stack_t ss, oss; 580 int error; 581 582 if (uap->ss) { 583 error = copyin(uap->ss, &ss, sizeof(ss)); 584 if (error) 585 return (error); 586 } 587 588 error = kern_sigaltstack(uap->ss ? &ss : NULL, 589 uap->oss ? &oss : NULL); 590 591 if (error == 0 && uap->oss) 592 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 593 return (error); 594 } 595 596 /* 597 * Common code for kill process group/broadcast kill. 598 * cp is calling process. 599 */ 600 struct killpg_info { 601 int nfound; 602 int sig; 603 }; 604 605 static int killpg_all_callback(struct proc *p, void *data); 606 607 static int 608 killpg(int sig, int pgid, int all) 609 { 610 struct killpg_info info; 611 struct proc *cp = curproc; 612 struct proc *p; 613 struct pgrp *pgrp; 614 615 info.nfound = 0; 616 info.sig = sig; 617 618 if (all) { 619 /* 620 * broadcast 621 */ 622 allproc_scan(killpg_all_callback, &info); 623 } else { 624 if (pgid == 0) { 625 /* 626 * zero pgid means send to my process group. 627 */ 628 pgrp = cp->p_pgrp; 629 } else { 630 pgrp = pgfind(pgid); 631 if (pgrp == NULL) 632 return (ESRCH); 633 } 634 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 635 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 636 if (p->p_pid <= 1 || 637 (p->p_flag & (P_SYSTEM | P_ZOMBIE)) || 638 !CANSIGNAL(p, sig)) { 639 continue; 640 } 641 ++info.nfound; 642 if (sig) 643 ksignal(p, sig); 644 } 645 lockmgr(&pgrp->pg_lock, LK_RELEASE); 646 } 647 return (info.nfound ? 0 : ESRCH); 648 } 649 650 static int 651 killpg_all_callback(struct proc *p, void *data) 652 { 653 struct killpg_info *info = data; 654 655 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 656 p == curproc || !CANSIGNAL(p, info->sig)) { 657 return (0); 658 } 659 ++info->nfound; 660 if (info->sig) 661 ksignal(p, info->sig); 662 return(0); 663 } 664 665 int 666 kern_kill(int sig, int pid) 667 { 668 struct thread *td = curthread; 669 struct proc *p = td->td_proc; 670 671 if ((u_int)sig > _SIG_MAXSIG) 672 return (EINVAL); 673 if (pid > 0) { 674 /* kill single process */ 675 if ((p = pfind(pid)) == NULL) 676 return (ESRCH); 677 if (!CANSIGNAL(p, sig)) 678 return (EPERM); 679 if (sig) 680 ksignal(p, sig); 681 return (0); 682 } 683 switch (pid) { 684 case -1: /* broadcast signal */ 685 return (killpg(sig, 0, 1)); 686 case 0: /* signal own process group */ 687 return (killpg(sig, 0, 0)); 688 default: /* negative explicit process group */ 689 return (killpg(sig, -pid, 0)); 690 } 691 /* NOTREACHED */ 692 } 693 694 int 695 sys_kill(struct kill_args *uap) 696 { 697 int error; 698 699 error = kern_kill(uap->signum, uap->pid); 700 701 return (error); 702 } 703 704 /* 705 * Send a signal to a process group. 706 */ 707 void 708 gsignal(int pgid, int sig) 709 { 710 struct pgrp *pgrp; 711 712 if (pgid && (pgrp = pgfind(pgid))) 713 pgsignal(pgrp, sig, 0); 714 } 715 716 /* 717 * Send a signal to a process group. If checktty is 1, 718 * limit to members which have a controlling terminal. 719 * 720 * pg_lock interlocks against a fork that might be in progress, to 721 * ensure that the new child process picks up the signal. 722 */ 723 void 724 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 725 { 726 struct proc *p; 727 728 if (pgrp) { 729 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 730 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 731 if (checkctty == 0 || p->p_flag & P_CONTROLT) 732 ksignal(p, sig); 733 } 734 lockmgr(&pgrp->pg_lock, LK_RELEASE); 735 } 736 } 737 738 /* 739 * Send a signal caused by a trap to the current process. 740 * If it will be caught immediately, deliver it with correct code. 741 * Otherwise, post it normally. 742 */ 743 void 744 trapsignal(struct proc *p, int sig, u_long code) 745 { 746 struct sigacts *ps = p->p_sigacts; 747 748 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 749 !SIGISMEMBER(p->p_sigmask, sig)) { 750 p->p_stats->p_ru.ru_nsignals++; 751 #ifdef KTRACE 752 if (KTRPOINT(p->p_thread, KTR_PSIG)) 753 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)], 754 &p->p_sigmask, code); 755 #endif 756 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 757 &p->p_sigmask, code); 758 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 759 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 760 SIGADDSET(p->p_sigmask, sig); 761 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 762 /* 763 * See kern_sigaction() for origin of this code. 764 */ 765 SIGDELSET(p->p_sigcatch, sig); 766 if (sig != SIGCONT && 767 sigprop(sig) & SA_IGNORE) 768 SIGADDSET(p->p_sigignore, sig); 769 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 770 } 771 } else { 772 p->p_code = code; /* XXX for core dump/debugger */ 773 p->p_sig = sig; /* XXX to verify code */ 774 ksignal(p, sig); 775 } 776 } 777 778 /* 779 * Send the signal to the process. If the signal has an action, the action 780 * is usually performed by the target process rather than the caller; we add 781 * the signal to the set of pending signals for the process. 782 * 783 * Exceptions: 784 * o When a stop signal is sent to a sleeping process that takes the 785 * default action, the process is stopped without awakening it. 786 * o SIGCONT restarts stopped processes (or puts them back to sleep) 787 * regardless of the signal action (eg, blocked or ignored). 788 * 789 * Other ignored signals are discarded immediately. 790 */ 791 void 792 ksignal(struct proc *p, int sig) 793 { 794 struct lwp *lp = &p->p_lwp; 795 int prop; 796 sig_t action; 797 798 if (sig > _SIG_MAXSIG || sig <= 0) { 799 printf("ksignal: signal %d\n", sig); 800 panic("ksignal signal number"); 801 } 802 803 crit_enter(); 804 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 805 crit_exit(); 806 807 prop = sigprop(sig); 808 809 /* 810 * If proc is traced, always give parent a chance; 811 * if signal event is tracked by procfs, give *that* 812 * a chance, as well. 813 */ 814 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 815 action = SIG_DFL; 816 } else { 817 /* 818 * If the signal is being ignored, 819 * then we forget about it immediately. 820 * (Note: we don't set SIGCONT in p_sigignore, 821 * and if it is set to SIG_IGN, 822 * action will be SIG_DFL here.) 823 */ 824 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 825 return; 826 if (SIGISMEMBER(p->p_sigmask, sig)) 827 action = SIG_HOLD; 828 else if (SIGISMEMBER(p->p_sigcatch, sig)) 829 action = SIG_CATCH; 830 else 831 action = SIG_DFL; 832 } 833 834 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 835 (p->p_flag & P_TRACED) == 0) { 836 p->p_nice = NZERO; 837 } 838 839 /* 840 * If continuing, clear any pending STOP signals. 841 */ 842 if (prop & SA_CONT) 843 SIG_STOPSIGMASK(p->p_siglist); 844 845 if (prop & SA_STOP) { 846 /* 847 * If sending a tty stop signal to a member of an orphaned 848 * process group, discard the signal here if the action 849 * is default; don't stop the process below if sleeping, 850 * and don't clear any pending SIGCONT. 851 */ 852 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 853 action == SIG_DFL) { 854 return; 855 } 856 SIG_CONTSIGMASK(p->p_siglist); 857 } 858 SIGADDSET(p->p_siglist, sig); 859 860 /* 861 * Defer further processing for signals which are held, 862 * except that stopped processes must be continued by SIGCONT. 863 */ 864 if (action == SIG_HOLD) { 865 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0) 866 return; 867 } 868 869 crit_enter(); 870 871 /* 872 * Process is in tsleep and not stopped 873 */ 874 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) { 875 /* 876 * If the process is sleeping uninterruptibly 877 * we can't interrupt the sleep... the signal will 878 * be noticed when the process returns through 879 * trap() or syscall(). 880 */ 881 if ((p->p_flag & P_SINTR) == 0) 882 goto out; 883 884 /* 885 * If the process is sleeping and traced, make it runnable 886 * so it can discover the signal in issignal() and stop 887 * for the parent. 888 * 889 * If the process is stopped and traced, no further action 890 * is necessary. 891 */ 892 if (p->p_flag & P_TRACED) 893 goto run; 894 895 /* 896 * If the process is sleeping and SA_CONT, and the signal 897 * mode is SIG_DFL, then make the process runnable. 898 * 899 * However, do *NOT* set P_BREAKTSLEEP. We do not want 900 * a SIGCONT to terminate an interruptable tsleep early 901 * and generate a spurious EINTR. 902 */ 903 if ((prop & SA_CONT) && action == SIG_DFL) { 904 SIGDELSET(p->p_siglist, sig); 905 goto run_no_break; 906 } 907 908 /* 909 * If the process is sleeping and receives a STOP signal, 910 * process immediately if possible. All other (caught or 911 * default) signals cause the process to run. 912 */ 913 if (prop & SA_STOP) { 914 if (action != SIG_DFL) 915 goto run; 916 917 /* 918 * If a child holding parent blocked, stopping 919 * could cause deadlock. Take no action at this 920 * time. 921 */ 922 if (p->p_flag & P_PPWAIT) 923 goto out; 924 925 /* 926 * Do not actually try to manipulate the process 927 * while it is sleeping, simply set P_STOPPED to 928 * indicate that it should stop as soon as it safely 929 * can. 930 */ 931 SIGDELSET(p->p_siglist, sig); 932 p->p_flag |= P_STOPPED; 933 p->p_flag &= ~P_WAITED; 934 p->p_xstat = sig; 935 wakeup(p->p_pptr); 936 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 937 ksignal(p->p_pptr, SIGCHLD); 938 goto out; 939 } 940 941 /* 942 * Otherwise the signal can interrupt the sleep. 943 */ 944 goto run; 945 } 946 947 /* 948 * Process is in tsleep and is stopped 949 */ 950 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) { 951 /* 952 * If the process is stopped and is being traced, then no 953 * further action is necessary. 954 */ 955 if (p->p_flag & P_TRACED) 956 goto out; 957 958 /* 959 * If the process is stopped and receives a KILL signal, 960 * make the process runnable. 961 */ 962 if (sig == SIGKILL) 963 goto run; 964 965 /* 966 * If the process is stopped and receives a CONT signal, 967 * then try to make the process runnable again. 968 */ 969 if (prop & SA_CONT) { 970 /* 971 * If SIGCONT is default (or ignored), we continue the 972 * process but don't leave the signal in p_siglist, as 973 * it has no further action. If SIGCONT is held, we 974 * continue the process and leave the signal in 975 * p_siglist. If the process catches SIGCONT, let it 976 * handle the signal itself. 977 */ 978 if (action == SIG_DFL) 979 SIGDELSET(p->p_siglist, sig); 980 if (action == SIG_CATCH) 981 goto run; 982 983 /* 984 * Make runnable but do not break a tsleep unless 985 * some other signal was pending. 986 */ 987 goto run_no_break; 988 } 989 990 /* 991 * If the process is stopped and receives another STOP 992 * signal, we do not need to stop it again. If we did 993 * the shell could get confused. 994 */ 995 if (prop & SA_STOP) { 996 SIGDELSET(p->p_siglist, sig); 997 goto out; 998 } 999 1000 /* 1001 * Otherwise the process is sleeping interruptably but 1002 * is stopped, just set the P_BREAKTSLEEP flag and take 1003 * no further action. The next runnable action will wake 1004 * the process up. 1005 */ 1006 p->p_flag |= P_BREAKTSLEEP; 1007 goto out; 1008 } 1009 1010 /* 1011 * Otherwise the process is running 1012 * 1013 * SRUN, SIDL, SZOMB do nothing with the signal, 1014 * other than kicking ourselves if we are running. 1015 * It will either never be noticed, or noticed very soon. 1016 * 1017 * Note that p_thread may be NULL or may not be completely 1018 * initialized if the process is in the SIDL or SZOMB state. 1019 * 1020 * For SMP we may have to forward the request to another cpu. 1021 * YYY the MP lock prevents the target process from moving 1022 * to another cpu, see kern/kern_switch.c 1023 * 1024 * If the target thread is waiting on its message port, 1025 * wakeup the target thread so it can check (or ignore) 1026 * the new signal. YYY needs cleanup. 1027 */ 1028 if (lp == lwkt_preempted_proc()) { 1029 signotify(); 1030 } else if (p->p_stat == SRUN) { 1031 struct thread *td = p->p_thread; 1032 1033 KASSERT(td != NULL, 1034 ("pid %d NULL p_thread stat %d flags %08x", 1035 p->p_pid, p->p_stat, p->p_flag)); 1036 1037 #ifdef SMP 1038 if (td->td_gd != mycpu) 1039 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1040 else 1041 #endif 1042 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1043 lwkt_schedule(td); 1044 } 1045 goto out; 1046 /*NOTREACHED*/ 1047 run: 1048 /* 1049 * Make runnable and break out of any tsleep as well. 1050 */ 1051 p->p_flag |= P_BREAKTSLEEP; 1052 run_no_break: 1053 setrunnable(p); 1054 out: 1055 crit_exit(); 1056 } 1057 1058 #ifdef SMP 1059 1060 /* 1061 * This function is called via an IPI. We will be in a critical section but 1062 * the MP lock will NOT be held. Also note that by the time the ipi message 1063 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1064 */ 1065 static void 1066 signotify_remote(void *arg) 1067 { 1068 struct lwp *lp = arg; 1069 1070 if (lp == lwkt_preempted_proc()) { 1071 signotify(); 1072 } else { 1073 struct thread *td = lp->lwp_thread; 1074 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1075 lwkt_schedule(td); 1076 } 1077 } 1078 1079 #endif 1080 1081 static int 1082 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1083 { 1084 sigset_t savedmask, set; 1085 struct proc *p = curproc; 1086 int error, sig, hz, timevalid = 0; 1087 struct timespec rts, ets, ts; 1088 struct timeval tv; 1089 1090 error = 0; 1091 sig = 0; 1092 SIG_CANTMASK(waitset); 1093 savedmask = p->p_sigmask; 1094 1095 if (timeout) { 1096 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1097 timeout->tv_nsec < 1000000000) { 1098 timevalid = 1; 1099 getnanouptime(&rts); 1100 ets = rts; 1101 timespecadd(&ets, timeout); 1102 } 1103 } 1104 1105 for (;;) { 1106 set = p->p_siglist; 1107 SIGSETAND(set, waitset); 1108 if ((sig = sig_ffs(&set)) != 0) { 1109 SIGFILLSET(p->p_sigmask); 1110 SIGDELSET(p->p_sigmask, sig); 1111 SIG_CANTMASK(p->p_sigmask); 1112 sig = issignal(p); 1113 /* 1114 * It may be a STOP signal, in the case, issignal 1115 * returns 0, because we may stop there, and new 1116 * signal can come in, we should restart if we got 1117 * nothing. 1118 */ 1119 if (sig == 0) 1120 continue; 1121 else 1122 break; 1123 } 1124 1125 /* 1126 * Previous checking got nothing, and we retried but still 1127 * got nothing, we should return the error status. 1128 */ 1129 if (error) 1130 break; 1131 1132 /* 1133 * POSIX says this must be checked after looking for pending 1134 * signals. 1135 */ 1136 if (timeout) { 1137 if (!timevalid) { 1138 error = EINVAL; 1139 break; 1140 } 1141 getnanouptime(&rts); 1142 if (timespeccmp(&rts, &ets, >=)) { 1143 error = EAGAIN; 1144 break; 1145 } 1146 ts = ets; 1147 timespecsub(&ts, &rts); 1148 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1149 hz = tvtohz_high(&tv); 1150 } else 1151 hz = 0; 1152 1153 p->p_sigmask = savedmask; 1154 SIGSETNAND(p->p_sigmask, waitset); 1155 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1156 if (timeout) { 1157 if (error == ERESTART) { 1158 /* can not restart a timeout wait. */ 1159 error = EINTR; 1160 } else if (error == EAGAIN) { 1161 /* will calculate timeout by ourself. */ 1162 error = 0; 1163 } 1164 } 1165 /* Retry ... */ 1166 } 1167 1168 p->p_sigmask = savedmask; 1169 if (sig) { 1170 error = 0; 1171 bzero(info, sizeof(*info)); 1172 info->si_signo = sig; 1173 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1174 1175 if (sig == SIGKILL) 1176 sigexit(p, sig); 1177 } 1178 return (error); 1179 } 1180 1181 int 1182 sys_sigtimedwait(struct sigtimedwait_args *uap) 1183 { 1184 struct timespec ts; 1185 struct timespec *timeout; 1186 sigset_t set; 1187 siginfo_t info; 1188 int error; 1189 1190 if (uap->timeout) { 1191 error = copyin(uap->timeout, &ts, sizeof(ts)); 1192 if (error) 1193 return (error); 1194 timeout = &ts; 1195 } else { 1196 timeout = NULL; 1197 } 1198 error = copyin(uap->set, &set, sizeof(set)); 1199 if (error) 1200 return (error); 1201 error = kern_sigtimedwait(set, &info, timeout); 1202 if (error) 1203 return (error); 1204 if (uap->info) 1205 error = copyout(&info, uap->info, sizeof(info)); 1206 /* Repost if we got an error. */ 1207 if (error) 1208 ksignal(curproc, info.si_signo); 1209 else 1210 uap->sysmsg_result = info.si_signo; 1211 return (error); 1212 } 1213 1214 int 1215 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1216 { 1217 siginfo_t info; 1218 sigset_t set; 1219 int error; 1220 1221 error = copyin(uap->set, &set, sizeof(set)); 1222 if (error) 1223 return (error); 1224 error = kern_sigtimedwait(set, &info, NULL); 1225 if (error) 1226 return (error); 1227 if (uap->info) 1228 error = copyout(&info, uap->info, sizeof(info)); 1229 /* Repost if we got an error. */ 1230 if (error) 1231 ksignal(curproc, info.si_signo); 1232 else 1233 uap->sysmsg_result = info.si_signo; 1234 return (error); 1235 } 1236 1237 /* 1238 * If the current process has received a signal that would interrupt a 1239 * system call, return EINTR or ERESTART as appropriate. 1240 */ 1241 int 1242 iscaught(struct proc *p) 1243 { 1244 int sig; 1245 1246 if (p) { 1247 if ((sig = CURSIG(p)) != 0) { 1248 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1249 return (EINTR); 1250 return (ERESTART); 1251 } 1252 } 1253 return(EWOULDBLOCK); 1254 } 1255 1256 /* 1257 * If the current process has received a signal (should be caught or cause 1258 * termination, should interrupt current syscall), return the signal number. 1259 * Stop signals with default action are processed immediately, then cleared; 1260 * they aren't returned. This is checked after each entry to the system for 1261 * a syscall or trap (though this can usually be done without calling issignal 1262 * by checking the pending signal masks in the CURSIG macro.) The normal call 1263 * sequence is 1264 * 1265 * This routine is called via CURSIG/__cursig and the MP lock might not be 1266 * held. Obtain the MP lock for the duration of the operation. 1267 * 1268 * while (sig = CURSIG(curproc)) 1269 * postsig(sig); 1270 */ 1271 int 1272 issignal(struct proc *p) 1273 { 1274 sigset_t mask; 1275 int sig, prop; 1276 1277 get_mplock(); 1278 for (;;) { 1279 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1280 1281 mask = p->p_siglist; 1282 SIGSETNAND(mask, p->p_sigmask); 1283 if (p->p_flag & P_PPWAIT) 1284 SIG_STOPSIGMASK(mask); 1285 if (!SIGNOTEMPTY(mask)) { /* no signal to send */ 1286 rel_mplock(); 1287 return (0); 1288 } 1289 sig = sig_ffs(&mask); 1290 1291 STOPEVENT(p, S_SIG, sig); 1292 1293 /* 1294 * We should see pending but ignored signals 1295 * only if P_TRACED was on when they were posted. 1296 */ 1297 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1298 SIGDELSET(p->p_siglist, sig); 1299 continue; 1300 } 1301 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1302 /* 1303 * If traced, always stop, and stay stopped until 1304 * released by the parent. 1305 * 1306 * NOTE: P_STOPPED may get cleared during the loop, 1307 * but we do not re-notify the parent if we have 1308 * to loop several times waiting for the parent 1309 * to let us continue. 1310 */ 1311 p->p_xstat = sig; 1312 p->p_flag |= P_STOPPED; 1313 p->p_flag &= ~P_WAITED; 1314 ksignal(p->p_pptr, SIGCHLD); 1315 do { 1316 tstop(p); 1317 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1318 p->p_flag &= ~P_STOPPED; 1319 1320 /* 1321 * If parent wants us to take the signal, 1322 * then it will leave it in p->p_xstat; 1323 * otherwise we just look for signals again. 1324 */ 1325 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1326 sig = p->p_xstat; 1327 if (sig == 0) 1328 continue; 1329 1330 /* 1331 * Put the new signal into p_siglist. If the 1332 * signal is being masked, look for other signals. 1333 */ 1334 SIGADDSET(p->p_siglist, sig); 1335 if (SIGISMEMBER(p->p_sigmask, sig)) 1336 continue; 1337 1338 /* 1339 * If the traced bit got turned off, go back up 1340 * to the top to rescan signals. This ensures 1341 * that p_sig* and ps_sigact are consistent. 1342 */ 1343 if ((p->p_flag & P_TRACED) == 0) 1344 continue; 1345 } 1346 1347 prop = sigprop(sig); 1348 1349 /* 1350 * Decide whether the signal should be returned. 1351 * Return the signal's number, or fall through 1352 * to clear it from the pending mask. 1353 */ 1354 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1355 case (int)SIG_DFL: 1356 /* 1357 * Don't take default actions on system processes. 1358 */ 1359 if (p->p_pid <= 1) { 1360 #ifdef DIAGNOSTIC 1361 /* 1362 * Are you sure you want to ignore SIGSEGV 1363 * in init? XXX 1364 */ 1365 printf("Process (pid %lu) got signal %d\n", 1366 (u_long)p->p_pid, sig); 1367 #endif 1368 break; /* == ignore */ 1369 } 1370 1371 /* 1372 * Handle the in-kernel checkpoint action 1373 */ 1374 if (prop & SA_CKPT) { 1375 checkpoint_signal_handler(p); 1376 break; 1377 } 1378 1379 /* 1380 * If there is a pending stop signal to process 1381 * with default action, stop here, 1382 * then clear the signal. However, 1383 * if process is member of an orphaned 1384 * process group, ignore tty stop signals. 1385 */ 1386 if (prop & SA_STOP) { 1387 if (p->p_flag & P_TRACED || 1388 (p->p_pgrp->pg_jobc == 0 && 1389 prop & SA_TTYSTOP)) 1390 break; /* == ignore */ 1391 p->p_xstat = sig; 1392 p->p_flag |= P_STOPPED; 1393 p->p_flag &= ~P_WAITED; 1394 1395 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1396 ksignal(p->p_pptr, SIGCHLD); 1397 while (p->p_flag & P_STOPPED) { 1398 tstop(p); 1399 } 1400 break; 1401 } else if (prop & SA_IGNORE) { 1402 /* 1403 * Except for SIGCONT, shouldn't get here. 1404 * Default action is to ignore; drop it. 1405 */ 1406 break; /* == ignore */ 1407 } else { 1408 rel_mplock(); 1409 return (sig); 1410 } 1411 1412 /*NOTREACHED*/ 1413 1414 case (int)SIG_IGN: 1415 /* 1416 * Masking above should prevent us ever trying 1417 * to take action on an ignored signal other 1418 * than SIGCONT, unless process is traced. 1419 */ 1420 if ((prop & SA_CONT) == 0 && 1421 (p->p_flag & P_TRACED) == 0) 1422 printf("issignal\n"); 1423 break; /* == ignore */ 1424 1425 default: 1426 /* 1427 * This signal has an action, let 1428 * postsig() process it. 1429 */ 1430 rel_mplock(); 1431 return (sig); 1432 } 1433 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1434 } 1435 /* NOTREACHED */ 1436 } 1437 1438 /* 1439 * Take the action for the specified signal 1440 * from the current set of pending signals. 1441 */ 1442 void 1443 postsig(int sig) 1444 { 1445 struct thread *td = curthread; 1446 struct proc *p = td->td_proc; 1447 struct sigacts *ps = p->p_sigacts; 1448 sig_t action; 1449 sigset_t returnmask; 1450 int code; 1451 1452 KASSERT(sig != 0, ("postsig")); 1453 1454 SIGDELSET(p->p_siglist, sig); 1455 action = ps->ps_sigact[_SIG_IDX(sig)]; 1456 #ifdef KTRACE 1457 if (KTRPOINT(td, KTR_PSIG)) 1458 ktrpsig(p, sig, action, p->p_flag & P_OLDMASK ? 1459 &p->p_oldsigmask : &p->p_sigmask, 0); 1460 #endif 1461 STOPEVENT(p, S_SIG, sig); 1462 1463 if (action == SIG_DFL) { 1464 /* 1465 * Default action, where the default is to kill 1466 * the process. (Other cases were ignored above.) 1467 */ 1468 sigexit(p, sig); 1469 /* NOTREACHED */ 1470 } else { 1471 /* 1472 * If we get here, the signal must be caught. 1473 */ 1474 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), 1475 ("postsig action")); 1476 /* 1477 * Set the new mask value and also defer further 1478 * occurrences of this signal. 1479 * 1480 * Special case: user has done a sigsuspend. Here the 1481 * current mask is not of interest, but rather the 1482 * mask from before the sigsuspend is what we want 1483 * restored after the signal processing is completed. 1484 */ 1485 crit_enter(); 1486 if (p->p_flag & P_OLDMASK) { 1487 returnmask = p->p_oldsigmask; 1488 p->p_flag &= ~P_OLDMASK; 1489 } else { 1490 returnmask = p->p_sigmask; 1491 } 1492 1493 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1494 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1495 SIGADDSET(p->p_sigmask, sig); 1496 1497 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1498 /* 1499 * See kern_sigaction() for origin of this code. 1500 */ 1501 SIGDELSET(p->p_sigcatch, sig); 1502 if (sig != SIGCONT && 1503 sigprop(sig) & SA_IGNORE) 1504 SIGADDSET(p->p_sigignore, sig); 1505 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1506 } 1507 crit_exit(); 1508 p->p_stats->p_ru.ru_nsignals++; 1509 if (p->p_sig != sig) { 1510 code = 0; 1511 } else { 1512 code = p->p_code; 1513 p->p_code = 0; 1514 p->p_sig = 0; 1515 } 1516 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1517 } 1518 } 1519 1520 /* 1521 * Kill the current process for stated reason. 1522 */ 1523 void 1524 killproc(struct proc *p, char *why) 1525 { 1526 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, 1527 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1528 ksignal(p, SIGKILL); 1529 } 1530 1531 /* 1532 * Force the current process to exit with the specified signal, dumping core 1533 * if appropriate. We bypass the normal tests for masked and caught signals, 1534 * allowing unrecoverable failures to terminate the process without changing 1535 * signal state. Mark the accounting record with the signal termination. 1536 * If dumping core, save the signal number for the debugger. Calls exit and 1537 * does not return. 1538 */ 1539 void 1540 sigexit(struct proc *p, int sig) 1541 { 1542 p->p_acflag |= AXSIG; 1543 if (sigprop(sig) & SA_CORE) { 1544 p->p_sig = sig; 1545 /* 1546 * Log signals which would cause core dumps 1547 * (Log as LOG_INFO to appease those who don't want 1548 * these messages.) 1549 * XXX : Todo, as well as euid, write out ruid too 1550 */ 1551 if (coredump(p) == 0) 1552 sig |= WCOREFLAG; 1553 if (kern_logsigexit) 1554 log(LOG_INFO, 1555 "pid %d (%s), uid %d: exited on signal %d%s\n", 1556 p->p_pid, p->p_comm, 1557 p->p_ucred ? p->p_ucred->cr_uid : -1, 1558 sig &~ WCOREFLAG, 1559 sig & WCOREFLAG ? " (core dumped)" : ""); 1560 } 1561 exit1(W_EXITCODE(0, sig)); 1562 /* NOTREACHED */ 1563 } 1564 1565 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1566 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1567 sizeof(corefilename), "process corefile name format string"); 1568 1569 /* 1570 * expand_name(name, uid, pid) 1571 * Expand the name described in corefilename, using name, uid, and pid. 1572 * corefilename is a printf-like string, with three format specifiers: 1573 * %N name of process ("name") 1574 * %P process id (pid) 1575 * %U user id (uid) 1576 * For example, "%N.core" is the default; they can be disabled completely 1577 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1578 * This is controlled by the sysctl variable kern.corefile (see above). 1579 */ 1580 1581 static char * 1582 expand_name(const char *name, uid_t uid, pid_t pid) 1583 { 1584 char *temp; 1585 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1586 int i, n; 1587 char *format = corefilename; 1588 size_t namelen; 1589 1590 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1591 if (temp == NULL) 1592 return NULL; 1593 namelen = strlen(name); 1594 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1595 int l; 1596 switch (format[i]) { 1597 case '%': /* Format character */ 1598 i++; 1599 switch (format[i]) { 1600 case '%': 1601 temp[n++] = '%'; 1602 break; 1603 case 'N': /* process name */ 1604 if ((n + namelen) > MAXPATHLEN) { 1605 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1606 pid, name, uid, temp, name); 1607 kfree(temp, M_TEMP); 1608 return NULL; 1609 } 1610 memcpy(temp+n, name, namelen); 1611 n += namelen; 1612 break; 1613 case 'P': /* process id */ 1614 l = sprintf(buf, "%u", pid); 1615 if ((n + l) > MAXPATHLEN) { 1616 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1617 pid, name, uid, temp, name); 1618 kfree(temp, M_TEMP); 1619 return NULL; 1620 } 1621 memcpy(temp+n, buf, l); 1622 n += l; 1623 break; 1624 case 'U': /* user id */ 1625 l = sprintf(buf, "%u", uid); 1626 if ((n + l) > MAXPATHLEN) { 1627 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1628 pid, name, uid, temp, name); 1629 kfree(temp, M_TEMP); 1630 return NULL; 1631 } 1632 memcpy(temp+n, buf, l); 1633 n += l; 1634 break; 1635 default: 1636 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1637 } 1638 break; 1639 default: 1640 temp[n++] = format[i]; 1641 } 1642 } 1643 temp[n] = '\0'; 1644 return temp; 1645 } 1646 1647 /* 1648 * Dump a process' core. The main routine does some 1649 * policy checking, and creates the name of the coredump; 1650 * then it passes on a vnode and a size limit to the process-specific 1651 * coredump routine if there is one; if there _is not_ one, it returns 1652 * ENOSYS; otherwise it returns the error from the process-specific routine. 1653 */ 1654 1655 static int 1656 coredump(struct proc *p) 1657 { 1658 struct vnode *vp; 1659 struct ucred *cred = p->p_ucred; 1660 struct flock lf; 1661 struct nlookupdata nd; 1662 struct vattr vattr; 1663 int error, error1; 1664 char *name; /* name of corefile */ 1665 off_t limit; 1666 1667 STOPEVENT(p, S_CORE, 0); 1668 1669 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1670 return (EFAULT); 1671 1672 /* 1673 * Note that the bulk of limit checking is done after 1674 * the corefile is created. The exception is if the limit 1675 * for corefiles is 0, in which case we don't bother 1676 * creating the corefile at all. This layout means that 1677 * a corefile is truncated instead of not being created, 1678 * if it is larger than the limit. 1679 */ 1680 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1681 if (limit == 0) 1682 return EFBIG; 1683 1684 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1685 if (name == NULL) 1686 return (EINVAL); 1687 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1688 if (error == 0) 1689 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1690 kfree(name, M_TEMP); 1691 if (error) { 1692 nlookup_done(&nd); 1693 return (error); 1694 } 1695 vp = nd.nl_open_vp; 1696 nd.nl_open_vp = NULL; 1697 nlookup_done(&nd); 1698 1699 vn_unlock(vp); 1700 lf.l_whence = SEEK_SET; 1701 lf.l_start = 0; 1702 lf.l_len = 0; 1703 lf.l_type = F_WRLCK; 1704 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 1705 if (error) 1706 goto out2; 1707 1708 /* Don't dump to non-regular files or files with links. */ 1709 if (vp->v_type != VREG || 1710 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 1711 error = EFAULT; 1712 goto out1; 1713 } 1714 1715 VATTR_NULL(&vattr); 1716 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1717 vattr.va_size = 0; 1718 VOP_SETATTR(vp, &vattr, cred); 1719 p->p_acflag |= ACORE; 1720 vn_unlock(vp); 1721 1722 error = p->p_sysent->sv_coredump ? 1723 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1724 1725 out1: 1726 lf.l_type = F_UNLCK; 1727 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 1728 out2: 1729 error1 = vn_close(vp, FWRITE); 1730 if (error == 0) 1731 error = error1; 1732 return (error); 1733 } 1734 1735 /* 1736 * Nonexistent system call-- signal process (may want to handle it). 1737 * Flag error in case process won't see signal immediately (blocked or ignored). 1738 */ 1739 /* ARGSUSED */ 1740 int 1741 sys_nosys(struct nosys_args *args) 1742 { 1743 ksignal(curproc, SIGSYS); 1744 return (EINVAL); 1745 } 1746 1747 /* 1748 * Send a SIGIO or SIGURG signal to a process or process group using 1749 * stored credentials rather than those of the current process. 1750 */ 1751 void 1752 pgsigio(struct sigio *sigio, int sig, int checkctty) 1753 { 1754 if (sigio == NULL) 1755 return; 1756 1757 if (sigio->sio_pgid > 0) { 1758 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1759 sigio->sio_proc)) 1760 ksignal(sigio->sio_proc, sig); 1761 } else if (sigio->sio_pgid < 0) { 1762 struct proc *p; 1763 1764 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 1765 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 1766 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1767 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1768 ksignal(p, sig); 1769 } 1770 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 1771 } 1772 } 1773 1774 static int 1775 filt_sigattach(struct knote *kn) 1776 { 1777 struct proc *p = curproc; 1778 1779 kn->kn_ptr.p_proc = p; 1780 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1781 1782 /* XXX lock the proc here while adding to the list? */ 1783 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1784 1785 return (0); 1786 } 1787 1788 static void 1789 filt_sigdetach(struct knote *kn) 1790 { 1791 struct proc *p = kn->kn_ptr.p_proc; 1792 1793 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1794 } 1795 1796 /* 1797 * signal knotes are shared with proc knotes, so we apply a mask to 1798 * the hint in order to differentiate them from process hints. This 1799 * could be avoided by using a signal-specific knote list, but probably 1800 * isn't worth the trouble. 1801 */ 1802 static int 1803 filt_signal(struct knote *kn, long hint) 1804 { 1805 if (hint & NOTE_SIGNAL) { 1806 hint &= ~NOTE_SIGNAL; 1807 1808 if (kn->kn_id == hint) 1809 kn->kn_data++; 1810 } 1811 return (kn->kn_data != 0); 1812 } 1813