1 /* $OpenBSD: kern_sig.c,v 1.180 2015/05/05 02:13:46 guenther Exp $ */ 2 /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Theo de Raadt. All rights reserved. 6 * Copyright (c) 1982, 1986, 1989, 1991, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. 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 */ 40 41 #define SIGPROP /* include signal properties table */ 42 #include <sys/param.h> 43 #include <sys/signalvar.h> 44 #include <sys/resourcevar.h> 45 #include <sys/queue.h> 46 #include <sys/namei.h> 47 #include <sys/vnode.h> 48 #include <sys/event.h> 49 #include <sys/proc.h> 50 #include <sys/systm.h> 51 #include <sys/acct.h> 52 #include <sys/file.h> 53 #include <sys/filedesc.h> 54 #include <sys/kernel.h> 55 #include <sys/wait.h> 56 #include <sys/ktrace.h> 57 #include <sys/stat.h> 58 #include <sys/core.h> 59 #include <sys/malloc.h> 60 #include <sys/pool.h> 61 #include <sys/ptrace.h> 62 #include <sys/sched.h> 63 #include <sys/user.h> 64 65 #include <sys/mount.h> 66 #include <sys/syscallargs.h> 67 68 #include <uvm/uvm_extern.h> 69 70 int filt_sigattach(struct knote *kn); 71 void filt_sigdetach(struct knote *kn); 72 int filt_signal(struct knote *kn, long hint); 73 74 struct filterops sig_filtops = 75 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 76 77 void proc_stop(struct proc *p, int); 78 void proc_stop_sweep(void *); 79 struct timeout proc_stop_to; 80 81 int cansignal(struct proc *, struct process *, int); 82 83 struct pool sigacts_pool; /* memory pool for sigacts structures */ 84 85 /* 86 * Can thread p, send the signal signum to process qr? 87 */ 88 int 89 cansignal(struct proc *p, struct process *qr, int signum) 90 { 91 struct process *pr = p->p_p; 92 struct ucred *uc = p->p_ucred; 93 struct ucred *quc = qr->ps_ucred; 94 95 if (uc->cr_uid == 0) 96 return (1); /* root can always signal */ 97 98 if (pr == qr) 99 return (1); /* process can always signal itself */ 100 101 /* optimization: if the same creds then the tests below will pass */ 102 if (uc == quc) 103 return (1); 104 105 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 106 return (1); /* SIGCONT in session */ 107 108 /* 109 * Using kill(), only certain signals can be sent to setugid 110 * child processes 111 */ 112 if (qr->ps_flags & PS_SUGID) { 113 switch (signum) { 114 case 0: 115 case SIGKILL: 116 case SIGINT: 117 case SIGTERM: 118 case SIGALRM: 119 case SIGSTOP: 120 case SIGTTIN: 121 case SIGTTOU: 122 case SIGTSTP: 123 case SIGHUP: 124 case SIGUSR1: 125 case SIGUSR2: 126 if (uc->cr_ruid == quc->cr_ruid || 127 uc->cr_uid == quc->cr_ruid) 128 return (1); 129 } 130 return (0); 131 } 132 133 if (uc->cr_ruid == quc->cr_ruid || 134 uc->cr_ruid == quc->cr_svuid || 135 uc->cr_uid == quc->cr_ruid || 136 uc->cr_uid == quc->cr_svuid) 137 return (1); 138 return (0); 139 } 140 141 /* 142 * Initialize signal-related data structures. 143 */ 144 void 145 signal_init(void) 146 { 147 timeout_set(&proc_stop_to, proc_stop_sweep, NULL); 148 149 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, PR_WAITOK, 150 "sigapl", NULL); 151 } 152 153 /* 154 * Create an initial sigacts structure, using the same signal state 155 * as p. 156 */ 157 struct sigacts * 158 sigactsinit(struct process *pr) 159 { 160 struct sigacts *ps; 161 162 ps = pool_get(&sigacts_pool, PR_WAITOK); 163 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 164 ps->ps_refcnt = 1; 165 return (ps); 166 } 167 168 /* 169 * Share a sigacts structure. 170 */ 171 struct sigacts * 172 sigactsshare(struct process *pr) 173 { 174 struct sigacts *ps = pr->ps_sigacts; 175 176 ps->ps_refcnt++; 177 return ps; 178 } 179 180 /* 181 * Initialize a new sigaltstack structure. 182 */ 183 void 184 sigstkinit(struct sigaltstack *ss) 185 { 186 ss->ss_flags = SS_DISABLE; 187 ss->ss_size = 0; 188 ss->ss_sp = 0; 189 } 190 191 /* 192 * Make this process not share its sigacts, maintaining all 193 * signal state. 194 */ 195 void 196 sigactsunshare(struct process *pr) 197 { 198 struct sigacts *newps; 199 200 if (pr->ps_sigacts->ps_refcnt == 1) 201 return; 202 203 newps = sigactsinit(pr); 204 sigactsfree(pr); 205 pr->ps_sigacts = newps; 206 } 207 208 /* 209 * Release a sigacts structure. 210 */ 211 void 212 sigactsfree(struct process *pr) 213 { 214 struct sigacts *ps = pr->ps_sigacts; 215 216 if (--ps->ps_refcnt > 0) 217 return; 218 219 pr->ps_sigacts = NULL; 220 221 pool_put(&sigacts_pool, ps); 222 } 223 224 /* ARGSUSED */ 225 int 226 sys_sigaction(struct proc *p, void *v, register_t *retval) 227 { 228 struct sys_sigaction_args /* { 229 syscallarg(int) signum; 230 syscallarg(const struct sigaction *) nsa; 231 syscallarg(struct sigaction *) osa; 232 } */ *uap = v; 233 struct sigaction vec; 234 #ifdef KTRACE 235 struct sigaction ovec; 236 #endif 237 struct sigaction *sa; 238 const struct sigaction *nsa; 239 struct sigaction *osa; 240 struct sigacts *ps = p->p_p->ps_sigacts; 241 int signum; 242 int bit, error; 243 244 signum = SCARG(uap, signum); 245 nsa = SCARG(uap, nsa); 246 osa = SCARG(uap, osa); 247 248 if (signum <= 0 || signum >= NSIG || 249 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 250 return (EINVAL); 251 sa = &vec; 252 if (osa) { 253 sa->sa_handler = ps->ps_sigact[signum]; 254 sa->sa_mask = ps->ps_catchmask[signum]; 255 bit = sigmask(signum); 256 sa->sa_flags = 0; 257 if ((ps->ps_sigonstack & bit) != 0) 258 sa->sa_flags |= SA_ONSTACK; 259 if ((ps->ps_sigintr & bit) == 0) 260 sa->sa_flags |= SA_RESTART; 261 if ((ps->ps_sigreset & bit) != 0) 262 sa->sa_flags |= SA_RESETHAND; 263 if ((ps->ps_siginfo & bit) != 0) 264 sa->sa_flags |= SA_SIGINFO; 265 if (signum == SIGCHLD) { 266 if ((ps->ps_flags & SAS_NOCLDSTOP) != 0) 267 sa->sa_flags |= SA_NOCLDSTOP; 268 if ((ps->ps_flags & SAS_NOCLDWAIT) != 0) 269 sa->sa_flags |= SA_NOCLDWAIT; 270 } 271 if ((sa->sa_mask & bit) == 0) 272 sa->sa_flags |= SA_NODEFER; 273 sa->sa_mask &= ~bit; 274 error = copyout(sa, osa, sizeof (vec)); 275 if (error) 276 return (error); 277 #ifdef KTRACE 278 if (KTRPOINT(p, KTR_STRUCT)) 279 ovec = vec; 280 #endif 281 } 282 if (nsa) { 283 error = copyin(nsa, sa, sizeof (vec)); 284 if (error) 285 return (error); 286 #ifdef KTRACE 287 if (KTRPOINT(p, KTR_STRUCT)) 288 ktrsigaction(p, sa); 289 #endif 290 setsigvec(p, signum, sa); 291 } 292 #ifdef KTRACE 293 if (osa && KTRPOINT(p, KTR_STRUCT)) 294 ktrsigaction(p, &ovec); 295 #endif 296 return (0); 297 } 298 299 void 300 setsigvec(struct proc *p, int signum, struct sigaction *sa) 301 { 302 struct sigacts *ps = p->p_p->ps_sigacts; 303 int bit; 304 int s; 305 306 bit = sigmask(signum); 307 /* 308 * Change setting atomically. 309 */ 310 s = splhigh(); 311 ps->ps_sigact[signum] = sa->sa_handler; 312 if ((sa->sa_flags & SA_NODEFER) == 0) 313 sa->sa_mask |= sigmask(signum); 314 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 315 if (signum == SIGCHLD) { 316 if (sa->sa_flags & SA_NOCLDSTOP) 317 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 318 else 319 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 320 /* 321 * If the SA_NOCLDWAIT flag is set or the handler 322 * is SIG_IGN we reparent the dying child to PID 1 323 * (init) which will reap the zombie. Because we use 324 * init to do our dirty work we never set SAS_NOCLDWAIT 325 * for PID 1. 326 * XXX exit1 rework means this is unnecessary? 327 */ 328 if (initprocess->ps_sigacts != ps && 329 ((sa->sa_flags & SA_NOCLDWAIT) || 330 sa->sa_handler == SIG_IGN)) 331 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 332 else 333 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 334 } 335 if ((sa->sa_flags & SA_RESETHAND) != 0) 336 ps->ps_sigreset |= bit; 337 else 338 ps->ps_sigreset &= ~bit; 339 if ((sa->sa_flags & SA_SIGINFO) != 0) 340 ps->ps_siginfo |= bit; 341 else 342 ps->ps_siginfo &= ~bit; 343 if ((sa->sa_flags & SA_RESTART) == 0) 344 ps->ps_sigintr |= bit; 345 else 346 ps->ps_sigintr &= ~bit; 347 if ((sa->sa_flags & SA_ONSTACK) != 0) 348 ps->ps_sigonstack |= bit; 349 else 350 ps->ps_sigonstack &= ~bit; 351 /* 352 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 353 * and for signals set to SIG_DFL where the default is to ignore. 354 * However, don't put SIGCONT in ps_sigignore, 355 * as we have to restart the process. 356 */ 357 if (sa->sa_handler == SIG_IGN || 358 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 359 atomic_clearbits_int(&p->p_siglist, bit); 360 if (signum != SIGCONT) 361 ps->ps_sigignore |= bit; /* easier in psignal */ 362 ps->ps_sigcatch &= ~bit; 363 } else { 364 ps->ps_sigignore &= ~bit; 365 if (sa->sa_handler == SIG_DFL) 366 ps->ps_sigcatch &= ~bit; 367 else 368 ps->ps_sigcatch |= bit; 369 } 370 splx(s); 371 } 372 373 /* 374 * Initialize signal state for process 0; 375 * set to ignore signals that are ignored by default. 376 */ 377 void 378 siginit(struct process *pr) 379 { 380 struct sigacts *ps = pr->ps_sigacts; 381 int i; 382 383 for (i = 0; i < NSIG; i++) 384 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 385 ps->ps_sigignore |= sigmask(i); 386 ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 387 } 388 389 /* 390 * Reset signals for an exec by the specified thread. 391 */ 392 void 393 execsigs(struct proc *p) 394 { 395 struct sigacts *ps; 396 int nc, mask; 397 398 sigactsunshare(p->p_p); 399 ps = p->p_p->ps_sigacts; 400 401 /* 402 * Reset caught signals. Held signals remain held 403 * through p_sigmask (unless they were caught, 404 * and are now ignored by default). 405 */ 406 while (ps->ps_sigcatch) { 407 nc = ffs((long)ps->ps_sigcatch); 408 mask = sigmask(nc); 409 ps->ps_sigcatch &= ~mask; 410 if (sigprop[nc] & SA_IGNORE) { 411 if (nc != SIGCONT) 412 ps->ps_sigignore |= mask; 413 atomic_clearbits_int(&p->p_siglist, mask); 414 } 415 ps->ps_sigact[nc] = SIG_DFL; 416 } 417 /* 418 * Reset stack state to the user stack. 419 * Clear set of signals caught on the signal stack. 420 */ 421 sigstkinit(&p->p_sigstk); 422 ps->ps_flags &= ~SAS_NOCLDWAIT; 423 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 424 ps->ps_sigact[SIGCHLD] = SIG_DFL; 425 } 426 427 /* 428 * Manipulate signal mask. 429 * Note that we receive new mask, not pointer, 430 * and return old mask as return value; 431 * the library stub does the rest. 432 */ 433 int 434 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 435 { 436 struct sys_sigprocmask_args /* { 437 syscallarg(int) how; 438 syscallarg(sigset_t) mask; 439 } */ *uap = v; 440 int error = 0; 441 sigset_t mask; 442 443 *retval = p->p_sigmask; 444 mask = SCARG(uap, mask) &~ sigcantmask; 445 446 switch (SCARG(uap, how)) { 447 case SIG_BLOCK: 448 atomic_setbits_int(&p->p_sigmask, mask); 449 break; 450 case SIG_UNBLOCK: 451 atomic_clearbits_int(&p->p_sigmask, mask); 452 break; 453 case SIG_SETMASK: 454 p->p_sigmask = mask; 455 break; 456 default: 457 error = EINVAL; 458 break; 459 } 460 return (error); 461 } 462 463 /* ARGSUSED */ 464 int 465 sys_sigpending(struct proc *p, void *v, register_t *retval) 466 { 467 468 *retval = p->p_siglist; 469 return (0); 470 } 471 472 /* 473 * Temporarily replace calling proc's signal mask for the duration of a 474 * system call. Original signal mask will be restored by userret(). 475 */ 476 void 477 dosigsuspend(struct proc *p, sigset_t newmask) 478 { 479 KASSERT(p == curproc); 480 481 p->p_oldmask = p->p_sigmask; 482 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 483 p->p_sigmask = newmask; 484 } 485 486 /* 487 * Suspend process until signal, providing mask to be set 488 * in the meantime. Note nonstandard calling convention: 489 * libc stub passes mask, not pointer, to save a copyin. 490 */ 491 /* ARGSUSED */ 492 int 493 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 494 { 495 struct sys_sigsuspend_args /* { 496 syscallarg(int) mask; 497 } */ *uap = v; 498 struct process *pr = p->p_p; 499 struct sigacts *ps = pr->ps_sigacts; 500 501 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 502 while (tsleep(ps, PPAUSE|PCATCH, "pause", 0) == 0) 503 /* void */; 504 /* always return EINTR rather than ERESTART... */ 505 return (EINTR); 506 } 507 508 int 509 sigonstack(size_t stack) 510 { 511 const struct sigaltstack *ss = &curproc->p_sigstk; 512 513 return (ss->ss_flags & SS_DISABLE ? 0 : 514 (stack - (size_t)ss->ss_sp < ss->ss_size)); 515 } 516 517 int 518 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 519 { 520 struct sys_sigaltstack_args /* { 521 syscallarg(const struct sigaltstack *) nss; 522 syscallarg(struct sigaltstack *) oss; 523 } */ *uap = v; 524 struct sigaltstack ss; 525 const struct sigaltstack *nss; 526 struct sigaltstack *oss; 527 int onstack = sigonstack(PROC_STACK(p)); 528 int error; 529 530 nss = SCARG(uap, nss); 531 oss = SCARG(uap, oss); 532 533 if (oss != NULL) { 534 ss = p->p_sigstk; 535 if (onstack) 536 ss.ss_flags |= SS_ONSTACK; 537 if ((error = copyout(&ss, oss, sizeof(ss)))) 538 return (error); 539 } 540 if (nss == NULL) 541 return (0); 542 error = copyin(nss, &ss, sizeof(ss)); 543 if (error) 544 return (error); 545 if (onstack) 546 return (EPERM); 547 if (ss.ss_flags & ~SS_DISABLE) 548 return (EINVAL); 549 if (ss.ss_flags & SS_DISABLE) { 550 p->p_sigstk.ss_flags = ss.ss_flags; 551 return (0); 552 } 553 if (ss.ss_size < MINSIGSTKSZ) 554 return (ENOMEM); 555 p->p_sigstk = ss; 556 return (0); 557 } 558 559 /* ARGSUSED */ 560 int 561 sys_kill(struct proc *cp, void *v, register_t *retval) 562 { 563 struct sys_kill_args /* { 564 syscallarg(int) pid; 565 syscallarg(int) signum; 566 } */ *uap = v; 567 struct proc *p; 568 int pid = SCARG(uap, pid); 569 int signum = SCARG(uap, signum); 570 571 if (((u_int)signum) >= NSIG) 572 return (EINVAL); 573 if (pid > 0) { 574 enum signal_type type = SPROCESS; 575 576 /* 577 * If the target pid is > THREAD_PID_OFFSET then this 578 * must be a kill of another thread in the same process. 579 * Otherwise, this is a process kill and the target must 580 * be a main thread. 581 */ 582 if (pid > THREAD_PID_OFFSET) { 583 if ((p = pfind(pid - THREAD_PID_OFFSET)) == NULL) 584 return (ESRCH); 585 if (p->p_p != cp->p_p) 586 return (ESRCH); 587 type = STHREAD; 588 } else { 589 /* XXX use prfind() */ 590 if ((p = pfind(pid)) == NULL) 591 return (ESRCH); 592 if (p->p_flag & P_THREAD) 593 return (ESRCH); 594 if (!cansignal(cp, p->p_p, signum)) 595 return (EPERM); 596 } 597 598 /* kill single process or thread */ 599 if (signum) 600 ptsignal(p, signum, type); 601 return (0); 602 } 603 switch (pid) { 604 case -1: /* broadcast signal */ 605 return (killpg1(cp, signum, 0, 1)); 606 case 0: /* signal own process group */ 607 return (killpg1(cp, signum, 0, 0)); 608 default: /* negative explicit process group */ 609 return (killpg1(cp, signum, -pid, 0)); 610 } 611 /* NOTREACHED */ 612 } 613 614 /* 615 * Common code for kill process group/broadcast kill. 616 * cp is calling process. 617 */ 618 int 619 killpg1(struct proc *cp, int signum, int pgid, int all) 620 { 621 struct process *pr; 622 struct pgrp *pgrp; 623 int nfound = 0; 624 625 if (all) 626 /* 627 * broadcast 628 */ 629 LIST_FOREACH(pr, &allprocess, ps_list) { 630 if (pr->ps_pid <= 1 || 631 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 632 pr == cp->p_p || !cansignal(cp, pr, signum)) 633 continue; 634 nfound++; 635 if (signum) 636 prsignal(pr, signum); 637 } 638 else { 639 if (pgid == 0) 640 /* 641 * zero pgid means send to my process group. 642 */ 643 pgrp = cp->p_p->ps_pgrp; 644 else { 645 pgrp = pgfind(pgid); 646 if (pgrp == NULL) 647 return (ESRCH); 648 } 649 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 650 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 651 !cansignal(cp, pr, signum)) 652 continue; 653 nfound++; 654 if (signum) 655 prsignal(pr, signum); 656 } 657 } 658 return (nfound ? 0 : ESRCH); 659 } 660 661 #define CANDELIVER(uid, euid, pr) \ 662 (euid == 0 || \ 663 (uid) == (pr)->ps_ucred->cr_ruid || \ 664 (uid) == (pr)->ps_ucred->cr_svuid || \ 665 (uid) == (pr)->ps_ucred->cr_uid || \ 666 (euid) == (pr)->ps_ucred->cr_ruid || \ 667 (euid) == (pr)->ps_ucred->cr_svuid || \ 668 (euid) == (pr)->ps_ucred->cr_uid) 669 670 /* 671 * Deliver signum to pgid, but first check uid/euid against each 672 * process and see if it is permitted. 673 */ 674 void 675 csignal(pid_t pgid, int signum, uid_t uid, uid_t euid) 676 { 677 struct pgrp *pgrp; 678 struct process *pr; 679 680 if (pgid == 0) 681 return; 682 if (pgid < 0) { 683 pgid = -pgid; 684 if ((pgrp = pgfind(pgid)) == NULL) 685 return; 686 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 687 if (CANDELIVER(uid, euid, pr)) 688 prsignal(pr, signum); 689 } else { 690 if ((pr = prfind(pgid)) == NULL) 691 return; 692 if (CANDELIVER(uid, euid, pr)) 693 prsignal(pr, signum); 694 } 695 } 696 697 /* 698 * Send a signal to a process group. 699 */ 700 void 701 gsignal(int pgid, int signum) 702 { 703 struct pgrp *pgrp; 704 705 if (pgid && (pgrp = pgfind(pgid))) 706 pgsignal(pgrp, signum, 0); 707 } 708 709 /* 710 * Send a signal to a process group. If checktty is 1, 711 * limit to members which have a controlling terminal. 712 */ 713 void 714 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 715 { 716 struct process *pr; 717 718 if (pgrp) 719 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 720 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 721 prsignal(pr, signum); 722 } 723 724 /* 725 * Send a signal caused by a trap to the current process. 726 * If it will be caught immediately, deliver it with correct code. 727 * Otherwise, post it normally. 728 */ 729 void 730 trapsignal(struct proc *p, int signum, u_long trapno, int code, 731 union sigval sigval) 732 { 733 struct process *pr = p->p_p; 734 struct sigacts *ps = pr->ps_sigacts; 735 int mask; 736 737 mask = sigmask(signum); 738 if ((pr->ps_flags & PS_TRACED) == 0 && 739 (ps->ps_sigcatch & mask) != 0 && 740 (p->p_sigmask & mask) == 0) { 741 #ifdef KTRACE 742 if (KTRPOINT(p, KTR_PSIG)) { 743 siginfo_t si; 744 745 initsiginfo(&si, signum, trapno, code, sigval); 746 ktrpsig(p, signum, ps->ps_sigact[signum], 747 p->p_sigmask, code, &si); 748 } 749 #endif 750 p->p_ru.ru_nsignals++; 751 (*pr->ps_emul->e_sendsig)(ps->ps_sigact[signum], signum, 752 p->p_sigmask, trapno, code, sigval); 753 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 754 if ((ps->ps_sigreset & mask) != 0) { 755 ps->ps_sigcatch &= ~mask; 756 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 757 ps->ps_sigignore |= mask; 758 ps->ps_sigact[signum] = SIG_DFL; 759 } 760 } else { 761 p->p_sisig = signum; 762 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 763 p->p_sicode = code; 764 p->p_sigval = sigval; 765 766 /* 767 * Signals like SIGBUS and SIGSEGV should not, when 768 * generated by the kernel, be ignorable or blockable. 769 * If it is and we're not being traced, then just kill 770 * the process. 771 */ 772 if ((pr->ps_flags & PS_TRACED) == 0 && 773 (sigprop[signum] & SA_KILL) && 774 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 775 sigexit(p, signum); 776 ptsignal(p, signum, STHREAD); 777 } 778 } 779 780 /* 781 * Send the signal to the process. If the signal has an action, the action 782 * is usually performed by the target process rather than the caller; we add 783 * the signal to the set of pending signals for the process. 784 * 785 * Exceptions: 786 * o When a stop signal is sent to a sleeping process that takes the 787 * default action, the process is stopped without awakening it. 788 * o SIGCONT restarts stopped processes (or puts them back to sleep) 789 * regardless of the signal action (eg, blocked or ignored). 790 * 791 * Other ignored signals are discarded immediately. 792 */ 793 void 794 psignal(struct proc *p, int signum) 795 { 796 ptsignal(p, signum, SPROCESS); 797 } 798 799 /* 800 * type = SPROCESS process signal, can be diverted (sigwait()) 801 * XXX if blocked in all threads, mark as pending in struct process 802 * type = STHREAD thread signal, but should be propagated if unhandled 803 * type = SPROPAGATED propagated to this thread, so don't propagate again 804 */ 805 void 806 ptsignal(struct proc *p, int signum, enum signal_type type) 807 { 808 int s, prop; 809 sig_t action; 810 int mask; 811 struct process *pr = p->p_p; 812 struct proc *q; 813 int wakeparent = 0; 814 815 #ifdef DIAGNOSTIC 816 if ((u_int)signum >= NSIG || signum == 0) 817 panic("psignal signal number"); 818 #endif 819 820 /* Ignore signal if we are exiting */ 821 if (pr->ps_flags & PS_EXITING) 822 return; 823 824 mask = sigmask(signum); 825 826 if (type == SPROCESS) { 827 /* Accept SIGKILL to coredumping processes */ 828 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 829 if (pr->ps_single != NULL) 830 p = pr->ps_single; 831 atomic_setbits_int(&p->p_siglist, mask); 832 return; 833 } 834 835 /* 836 * If the current thread can process the signal 837 * immediately (it's unblocked) then have it take it. 838 */ 839 q = curproc; 840 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 841 (q->p_sigmask & mask) == 0) 842 p = q; 843 else { 844 /* 845 * A process-wide signal can be diverted to a 846 * different thread that's in sigwait() for this 847 * signal. If there isn't such a thread, then 848 * pick a thread that doesn't have it blocked so 849 * that the stop/kill consideration isn't 850 * delayed. Otherwise, mark it pending on the 851 * main thread. 852 */ 853 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 854 /* ignore exiting threads */ 855 if (q->p_flag & P_WEXIT) 856 continue; 857 858 /* skip threads that have the signal blocked */ 859 if ((q->p_sigmask & mask) != 0) 860 continue; 861 862 /* okay, could send to this thread */ 863 p = q; 864 865 /* 866 * sigsuspend, sigwait, ppoll/pselect, etc? 867 * Definitely go to this thread, as it's 868 * already blocked in the kernel. 869 */ 870 if (q->p_flag & P_SIGSUSPEND) 871 break; 872 } 873 } 874 } 875 876 if (type != SPROPAGATED) 877 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 878 879 prop = sigprop[signum]; 880 881 /* 882 * If proc is traced, always give parent a chance. 883 */ 884 if (pr->ps_flags & PS_TRACED) { 885 action = SIG_DFL; 886 atomic_setbits_int(&p->p_siglist, mask); 887 } else { 888 /* 889 * If the signal is being ignored, 890 * then we forget about it immediately. 891 * (Note: we don't set SIGCONT in ps_sigignore, 892 * and if it is set to SIG_IGN, 893 * action will be SIG_DFL here.) 894 */ 895 if (pr->ps_sigacts->ps_sigignore & mask) 896 return; 897 if (p->p_sigmask & mask) { 898 action = SIG_HOLD; 899 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 900 action = SIG_CATCH; 901 } else { 902 action = SIG_DFL; 903 904 if (prop & SA_KILL && pr->ps_nice > NZERO) 905 pr->ps_nice = NZERO; 906 907 /* 908 * If sending a tty stop signal to a member of an 909 * orphaned process group, discard the signal here if 910 * the action is default; don't stop the process below 911 * if sleeping, and don't clear any pending SIGCONT. 912 */ 913 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 914 return; 915 } 916 917 atomic_setbits_int(&p->p_siglist, mask); 918 } 919 920 if (prop & SA_CONT) 921 atomic_clearbits_int(&p->p_siglist, stopsigmask); 922 923 if (prop & SA_STOP) { 924 atomic_clearbits_int(&p->p_siglist, contsigmask); 925 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 926 } 927 928 /* 929 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 930 */ 931 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 932 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 933 if (q != p) 934 ptsignal(q, signum, SPROPAGATED); 935 936 /* 937 * Defer further processing for signals which are held, 938 * except that stopped processes must be continued by SIGCONT. 939 */ 940 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 941 return; 942 943 SCHED_LOCK(s); 944 945 switch (p->p_stat) { 946 947 case SSLEEP: 948 /* 949 * If process is sleeping uninterruptibly 950 * we can't interrupt the sleep... the signal will 951 * be noticed when the process returns through 952 * trap() or syscall(). 953 */ 954 if ((p->p_flag & P_SINTR) == 0) 955 goto out; 956 /* 957 * Process is sleeping and traced... make it runnable 958 * so it can discover the signal in issignal() and stop 959 * for the parent. 960 */ 961 if (pr->ps_flags & PS_TRACED) 962 goto run; 963 /* 964 * If SIGCONT is default (or ignored) and process is 965 * asleep, we are finished; the process should not 966 * be awakened. 967 */ 968 if ((prop & SA_CONT) && action == SIG_DFL) { 969 atomic_clearbits_int(&p->p_siglist, mask); 970 goto out; 971 } 972 /* 973 * When a sleeping process receives a stop 974 * signal, process immediately if possible. 975 */ 976 if ((prop & SA_STOP) && action == SIG_DFL) { 977 /* 978 * If a child holding parent blocked, 979 * stopping could cause deadlock. 980 */ 981 if (pr->ps_flags & PS_PPWAIT) 982 goto out; 983 atomic_clearbits_int(&p->p_siglist, mask); 984 p->p_xstat = signum; 985 proc_stop(p, 0); 986 goto out; 987 } 988 /* 989 * All other (caught or default) signals 990 * cause the process to run. 991 */ 992 goto runfast; 993 /*NOTREACHED*/ 994 995 case SSTOP: 996 /* 997 * If traced process is already stopped, 998 * then no further action is necessary. 999 */ 1000 if (pr->ps_flags & PS_TRACED) 1001 goto out; 1002 1003 /* 1004 * Kill signal always sets processes running. 1005 */ 1006 if (signum == SIGKILL) { 1007 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1008 goto runfast; 1009 } 1010 1011 if (prop & SA_CONT) { 1012 /* 1013 * If SIGCONT is default (or ignored), we continue the 1014 * process but don't leave the signal in p_siglist, as 1015 * it has no further action. If SIGCONT is held, we 1016 * continue the process and leave the signal in 1017 * p_siglist. If the process catches SIGCONT, let it 1018 * handle the signal itself. If it isn't waiting on 1019 * an event, then it goes back to run state. 1020 * Otherwise, process goes back to sleep state. 1021 */ 1022 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1023 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1024 wakeparent = 1; 1025 if (action == SIG_DFL) 1026 atomic_clearbits_int(&p->p_siglist, mask); 1027 if (action == SIG_CATCH) 1028 goto runfast; 1029 if (p->p_wchan == 0) 1030 goto run; 1031 p->p_stat = SSLEEP; 1032 goto out; 1033 } 1034 1035 if (prop & SA_STOP) { 1036 /* 1037 * Already stopped, don't need to stop again. 1038 * (If we did the shell could get confused.) 1039 */ 1040 atomic_clearbits_int(&p->p_siglist, mask); 1041 goto out; 1042 } 1043 1044 /* 1045 * If process is sleeping interruptibly, then simulate a 1046 * wakeup so that when it is continued, it will be made 1047 * runnable and can look at the signal. But don't make 1048 * the process runnable, leave it stopped. 1049 */ 1050 if (p->p_wchan && p->p_flag & P_SINTR) 1051 unsleep(p); 1052 goto out; 1053 1054 case SONPROC: 1055 signotify(p); 1056 /* FALLTHROUGH */ 1057 default: 1058 /* 1059 * SRUN, SIDL, SDEAD do nothing with the signal, 1060 * other than kicking ourselves if we are running. 1061 * It will either never be noticed, or noticed very soon. 1062 */ 1063 goto out; 1064 } 1065 /*NOTREACHED*/ 1066 1067 runfast: 1068 /* 1069 * Raise priority to at least PUSER. 1070 */ 1071 if (p->p_priority > PUSER) 1072 p->p_priority = PUSER; 1073 run: 1074 setrunnable(p); 1075 out: 1076 SCHED_UNLOCK(s); 1077 if (wakeparent) 1078 wakeup(pr->ps_pptr); 1079 } 1080 1081 /* 1082 * If the current process has received a signal (should be caught or cause 1083 * termination, should interrupt current syscall), return the signal number. 1084 * Stop signals with default action are processed immediately, then cleared; 1085 * they aren't returned. This is checked after each entry to the system for 1086 * a syscall or trap (though this can usually be done without calling issignal 1087 * by checking the pending signal masks in the CURSIG macro.) The normal call 1088 * sequence is 1089 * 1090 * while (signum = CURSIG(curproc)) 1091 * postsig(signum); 1092 * 1093 * Assumes that if the P_SINTR flag is set, we're holding both the 1094 * kernel and scheduler locks. 1095 */ 1096 int 1097 issignal(struct proc *p) 1098 { 1099 struct process *pr = p->p_p; 1100 int signum, mask, prop; 1101 int dolock = (p->p_flag & P_SINTR) == 0; 1102 int s; 1103 1104 for (;;) { 1105 mask = p->p_siglist & ~p->p_sigmask; 1106 if (pr->ps_flags & PS_PPWAIT) 1107 mask &= ~stopsigmask; 1108 if (mask == 0) /* no signal to send */ 1109 return (0); 1110 signum = ffs((long)mask); 1111 mask = sigmask(signum); 1112 atomic_clearbits_int(&p->p_siglist, mask); 1113 1114 /* 1115 * We should see pending but ignored signals 1116 * only if PS_TRACED was on when they were posted. 1117 */ 1118 if (mask & pr->ps_sigacts->ps_sigignore && 1119 (pr->ps_flags & PS_TRACED) == 0) 1120 continue; 1121 1122 if ((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) { 1123 /* 1124 * If traced, always stop, and stay 1125 * stopped until released by the debugger. 1126 */ 1127 p->p_xstat = signum; 1128 1129 if (dolock) 1130 KERNEL_LOCK(); 1131 single_thread_set(p, SINGLE_PTRACE, 0); 1132 if (dolock) 1133 KERNEL_UNLOCK(); 1134 1135 if (dolock) 1136 SCHED_LOCK(s); 1137 proc_stop(p, 1); 1138 if (dolock) 1139 SCHED_UNLOCK(s); 1140 1141 if (dolock) 1142 KERNEL_LOCK(); 1143 single_thread_clear(p, 0); 1144 if (dolock) 1145 KERNEL_UNLOCK(); 1146 1147 /* 1148 * If we are no longer being traced, or the parent 1149 * didn't give us a signal, look for more signals. 1150 */ 1151 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1152 continue; 1153 1154 /* 1155 * If the new signal is being masked, look for other 1156 * signals. 1157 */ 1158 signum = p->p_xstat; 1159 mask = sigmask(signum); 1160 if ((p->p_sigmask & mask) != 0) 1161 continue; 1162 1163 /* take the signal! */ 1164 atomic_clearbits_int(&p->p_siglist, mask); 1165 } 1166 1167 prop = sigprop[signum]; 1168 1169 /* 1170 * Decide whether the signal should be returned. 1171 * Return the signal's number, or fall through 1172 * to clear it from the pending mask. 1173 */ 1174 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1175 case (long)SIG_DFL: 1176 /* 1177 * Don't take default actions on system processes. 1178 */ 1179 if (p->p_pid <= 1) { 1180 #ifdef DIAGNOSTIC 1181 /* 1182 * Are you sure you want to ignore SIGSEGV 1183 * in init? XXX 1184 */ 1185 printf("Process (pid %d) got signal %d\n", 1186 p->p_pid, signum); 1187 #endif 1188 break; /* == ignore */ 1189 } 1190 /* 1191 * If there is a pending stop signal to process 1192 * with default action, stop here, 1193 * then clear the signal. However, 1194 * if process is member of an orphaned 1195 * process group, ignore tty stop signals. 1196 */ 1197 if (prop & SA_STOP) { 1198 if (pr->ps_flags & PS_TRACED || 1199 (pr->ps_pgrp->pg_jobc == 0 && 1200 prop & SA_TTYSTOP)) 1201 break; /* == ignore */ 1202 p->p_xstat = signum; 1203 if (dolock) 1204 SCHED_LOCK(s); 1205 proc_stop(p, 1); 1206 if (dolock) 1207 SCHED_UNLOCK(s); 1208 break; 1209 } else if (prop & SA_IGNORE) { 1210 /* 1211 * Except for SIGCONT, shouldn't get here. 1212 * Default action is to ignore; drop it. 1213 */ 1214 break; /* == ignore */ 1215 } else 1216 goto keep; 1217 /*NOTREACHED*/ 1218 case (long)SIG_IGN: 1219 /* 1220 * Masking above should prevent us ever trying 1221 * to take action on an ignored signal other 1222 * than SIGCONT, unless process is traced. 1223 */ 1224 if ((prop & SA_CONT) == 0 && 1225 (pr->ps_flags & PS_TRACED) == 0) 1226 printf("issignal\n"); 1227 break; /* == ignore */ 1228 default: 1229 /* 1230 * This signal has an action, let 1231 * postsig() process it. 1232 */ 1233 goto keep; 1234 } 1235 } 1236 /* NOTREACHED */ 1237 1238 keep: 1239 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1240 return (signum); 1241 } 1242 1243 /* 1244 * Put the argument process into the stopped state and notify the parent 1245 * via wakeup. Signals are handled elsewhere. The process must not be 1246 * on the run queue. 1247 */ 1248 void 1249 proc_stop(struct proc *p, int sw) 1250 { 1251 struct process *pr = p->p_p; 1252 extern void *softclock_si; 1253 1254 #ifdef MULTIPROCESSOR 1255 SCHED_ASSERT_LOCKED(); 1256 #endif 1257 1258 p->p_stat = SSTOP; 1259 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1260 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1261 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1262 if (!timeout_pending(&proc_stop_to)) { 1263 timeout_add(&proc_stop_to, 0); 1264 /* 1265 * We need this soft interrupt to be handled fast. 1266 * Extra calls to softclock don't hurt. 1267 */ 1268 softintr_schedule(softclock_si); 1269 } 1270 if (sw) 1271 mi_switch(); 1272 } 1273 1274 /* 1275 * Called from a timeout to send signals to the parents of stopped processes. 1276 * We can't do this in proc_stop because it's called with nasty locks held 1277 * and we would need recursive scheduler lock to deal with that. 1278 */ 1279 void 1280 proc_stop_sweep(void *v) 1281 { 1282 struct process *pr; 1283 1284 LIST_FOREACH(pr, &allprocess, ps_list) { 1285 if ((pr->ps_flags & PS_STOPPED) == 0) 1286 continue; 1287 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1288 1289 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1290 prsignal(pr->ps_pptr, SIGCHLD); 1291 wakeup(pr->ps_pptr); 1292 } 1293 } 1294 1295 /* 1296 * Take the action for the specified signal 1297 * from the current set of pending signals. 1298 */ 1299 void 1300 postsig(int signum) 1301 { 1302 struct proc *p = curproc; 1303 struct process *pr = p->p_p; 1304 struct sigacts *ps = pr->ps_sigacts; 1305 sig_t action; 1306 u_long trapno; 1307 int mask, returnmask; 1308 union sigval sigval; 1309 int s, code; 1310 1311 #ifdef DIAGNOSTIC 1312 if (signum == 0) 1313 panic("postsig"); 1314 #endif 1315 1316 KERNEL_LOCK(); 1317 1318 mask = sigmask(signum); 1319 atomic_clearbits_int(&p->p_siglist, mask); 1320 action = ps->ps_sigact[signum]; 1321 sigval.sival_ptr = 0; 1322 1323 if (p->p_sisig != signum) { 1324 trapno = 0; 1325 code = SI_USER; 1326 sigval.sival_ptr = 0; 1327 } else { 1328 trapno = p->p_sitrapno; 1329 code = p->p_sicode; 1330 sigval = p->p_sigval; 1331 } 1332 1333 #ifdef KTRACE 1334 if (KTRPOINT(p, KTR_PSIG)) { 1335 siginfo_t si; 1336 1337 initsiginfo(&si, signum, trapno, code, sigval); 1338 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1339 p->p_oldmask : p->p_sigmask, code, &si); 1340 } 1341 #endif 1342 if (action == SIG_DFL) { 1343 /* 1344 * Default action, where the default is to kill 1345 * the process. (Other cases were ignored above.) 1346 */ 1347 sigexit(p, signum); 1348 /* NOTREACHED */ 1349 } else { 1350 /* 1351 * If we get here, the signal must be caught. 1352 */ 1353 #ifdef DIAGNOSTIC 1354 if (action == SIG_IGN || (p->p_sigmask & mask)) 1355 panic("postsig action"); 1356 #endif 1357 /* 1358 * Set the new mask value and also defer further 1359 * occurrences of this signal. 1360 * 1361 * Special case: user has done a sigpause. Here the 1362 * current mask is not of interest, but rather the 1363 * mask from before the sigpause is what we want 1364 * restored after the signal processing is completed. 1365 */ 1366 #ifdef MULTIPROCESSOR 1367 s = splsched(); 1368 #else 1369 s = splhigh(); 1370 #endif 1371 if (p->p_flag & P_SIGSUSPEND) { 1372 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1373 returnmask = p->p_oldmask; 1374 } else { 1375 returnmask = p->p_sigmask; 1376 } 1377 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 1378 if ((ps->ps_sigreset & mask) != 0) { 1379 ps->ps_sigcatch &= ~mask; 1380 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 1381 ps->ps_sigignore |= mask; 1382 ps->ps_sigact[signum] = SIG_DFL; 1383 } 1384 splx(s); 1385 p->p_ru.ru_nsignals++; 1386 if (p->p_sisig == signum) { 1387 p->p_sisig = 0; 1388 p->p_sitrapno = 0; 1389 p->p_sicode = SI_USER; 1390 p->p_sigval.sival_ptr = NULL; 1391 } 1392 1393 (*pr->ps_emul->e_sendsig)(action, signum, returnmask, trapno, 1394 code, sigval); 1395 } 1396 1397 KERNEL_UNLOCK(); 1398 } 1399 1400 /* 1401 * Force the current process to exit with the specified signal, dumping core 1402 * if appropriate. We bypass the normal tests for masked and caught signals, 1403 * allowing unrecoverable failures to terminate the process without changing 1404 * signal state. Mark the accounting record with the signal termination. 1405 * If dumping core, save the signal number for the debugger. Calls exit and 1406 * does not return. 1407 */ 1408 void 1409 sigexit(struct proc *p, int signum) 1410 { 1411 /* Mark process as going away */ 1412 atomic_setbits_int(&p->p_flag, P_WEXIT); 1413 1414 p->p_p->ps_acflag |= AXSIG; 1415 if (sigprop[signum] & SA_CORE) { 1416 p->p_sisig = signum; 1417 1418 /* if there are other threads, pause them */ 1419 if (TAILQ_FIRST(&p->p_p->ps_threads) != p || 1420 TAILQ_NEXT(p, p_thr_link) != NULL) 1421 single_thread_set(p, SINGLE_SUSPEND, 0); 1422 1423 if (coredump(p) == 0) 1424 signum |= WCOREFLAG; 1425 } 1426 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1427 /* NOTREACHED */ 1428 } 1429 1430 int nosuidcoredump = 1; 1431 1432 struct coredump_iostate { 1433 struct proc *io_proc; 1434 struct vnode *io_vp; 1435 struct ucred *io_cred; 1436 off_t io_offset; 1437 }; 1438 1439 /* 1440 * Dump core, into a file named "progname.core", unless the process was 1441 * setuid/setgid. 1442 */ 1443 int 1444 coredump(struct proc *p) 1445 { 1446 #ifdef SMALL_KERNEL 1447 return EPERM; 1448 #else 1449 struct process *pr = p->p_p; 1450 struct vnode *vp; 1451 struct ucred *cred = p->p_ucred; 1452 struct vmspace *vm = p->p_vmspace; 1453 struct nameidata nd; 1454 struct vattr vattr; 1455 struct coredump_iostate io; 1456 int error, len, incrash = 0; 1457 char name[MAXPATHLEN]; 1458 const char *dir = "/var/crash"; 1459 1460 if (pr->ps_emul->e_coredump == NULL) 1461 return (EINVAL); 1462 1463 pr->ps_flags |= PS_COREDUMP; 1464 1465 /* 1466 * If the process has inconsistant uids, nosuidcoredump 1467 * determines coredump placement policy. 1468 */ 1469 if (((pr->ps_flags & PS_SUGID) && (error = suser(p, 0))) || 1470 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1471 if (nosuidcoredump == 3 || nosuidcoredump == 2) 1472 incrash = 1; 1473 else 1474 return (EPERM); 1475 } 1476 1477 /* Don't dump if will exceed file size limit. */ 1478 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= 1479 p->p_rlimit[RLIMIT_CORE].rlim_cur) 1480 return (EFBIG); 1481 1482 if (incrash && nosuidcoredump == 3) { 1483 /* 1484 * If the program directory does not exist, dumps of 1485 * that core will silently fail. 1486 */ 1487 len = snprintf(name, sizeof(name), "%s/%s/%u.core", 1488 dir, p->p_comm, p->p_pid); 1489 } else if (incrash && nosuidcoredump == 2) 1490 len = snprintf(name, sizeof(name), "%s/%s.core", 1491 dir, p->p_comm); 1492 else 1493 len = snprintf(name, sizeof(name), "%s.core", p->p_comm); 1494 if (len >= sizeof(name)) 1495 return (EACCES); 1496 1497 /* 1498 * Control the UID used to write out. The normal case uses 1499 * the real UID. If the sugid case is going to write into the 1500 * controlled directory, we do so as root. 1501 */ 1502 if (incrash == 0) { 1503 cred = crdup(cred); 1504 cred->cr_uid = cred->cr_ruid; 1505 cred->cr_gid = cred->cr_rgid; 1506 } else { 1507 if (p->p_fd->fd_rdir) { 1508 vrele(p->p_fd->fd_rdir); 1509 p->p_fd->fd_rdir = NULL; 1510 } 1511 p->p_ucred = crdup(p->p_ucred); 1512 crfree(cred); 1513 cred = p->p_ucred; 1514 crhold(cred); 1515 cred->cr_uid = 0; 1516 cred->cr_gid = 0; 1517 } 1518 1519 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1520 1521 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1522 1523 if (error) 1524 goto out; 1525 1526 /* 1527 * Don't dump to non-regular files, files with links, or files 1528 * owned by someone else. 1529 */ 1530 vp = nd.ni_vp; 1531 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1532 VOP_UNLOCK(vp, 0, p); 1533 vn_close(vp, FWRITE, cred, p); 1534 goto out; 1535 } 1536 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1537 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1538 vattr.va_uid != cred->cr_uid) { 1539 error = EACCES; 1540 VOP_UNLOCK(vp, 0, p); 1541 vn_close(vp, FWRITE, cred, p); 1542 goto out; 1543 } 1544 VATTR_NULL(&vattr); 1545 vattr.va_size = 0; 1546 VOP_SETATTR(vp, &vattr, cred, p); 1547 pr->ps_acflag |= ACORE; 1548 1549 io.io_proc = p; 1550 io.io_vp = vp; 1551 io.io_cred = cred; 1552 io.io_offset = 0; 1553 VOP_UNLOCK(vp, 0, p); 1554 vref(vp); 1555 error = vn_close(vp, FWRITE, cred, p); 1556 if (error == 0) 1557 error = (*pr->ps_emul->e_coredump)(p, &io); 1558 vrele(vp); 1559 out: 1560 crfree(cred); 1561 return (error); 1562 #endif 1563 } 1564 1565 #ifndef SMALL_KERNEL 1566 int 1567 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1568 { 1569 struct coredump_iostate *io = cookie; 1570 off_t coffset = 0; 1571 size_t csize; 1572 int chunk, error; 1573 1574 csize = len; 1575 do { 1576 if (io->io_proc->p_siglist & sigmask(SIGKILL)) 1577 return (EINTR); 1578 1579 /* Rest of the loop sleeps with lock held, so... */ 1580 yield(); 1581 1582 chunk = MIN(csize, MAXPHYS); 1583 error = vn_rdwr(UIO_WRITE, io->io_vp, 1584 (caddr_t)data + coffset, chunk, 1585 io->io_offset + coffset, segflg, 1586 IO_UNIT, io->io_cred, NULL, io->io_proc); 1587 if (error) { 1588 printf("pid %d (%s): %s write of %lu@%p" 1589 " at %lld failed: %d\n", 1590 io->io_proc->p_pid, io->io_proc->p_comm, 1591 segflg == UIO_USERSPACE ? "user" : "system", 1592 len, data, (long long)io->io_offset, error); 1593 return (error); 1594 } 1595 1596 coffset += chunk; 1597 csize -= chunk; 1598 } while (csize > 0); 1599 1600 io->io_offset += len; 1601 return (0); 1602 } 1603 1604 void 1605 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1606 { 1607 struct coredump_iostate *io = cookie; 1608 1609 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1610 } 1611 1612 #endif /* !SMALL_KERNEL */ 1613 1614 /* 1615 * Nonexistent system call-- signal process (may want to handle it). 1616 * Flag error in case process won't see signal immediately (blocked or ignored). 1617 */ 1618 /* ARGSUSED */ 1619 int 1620 sys_nosys(struct proc *p, void *v, register_t *retval) 1621 { 1622 1623 ptsignal(p, SIGSYS, STHREAD); 1624 return (ENOSYS); 1625 } 1626 1627 int 1628 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1629 { 1630 static int sigwaitsleep; 1631 struct sys___thrsigdivert_args /* { 1632 syscallarg(sigset_t) sigmask; 1633 syscallarg(siginfo_t *) info; 1634 syscallarg(const struct timespec *) timeout; 1635 } */ *uap = v; 1636 struct process *pr = p->p_p; 1637 sigset_t *m; 1638 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1639 siginfo_t si; 1640 long long to_ticks = 0; 1641 int timeinvalid = 0; 1642 int error = 0; 1643 1644 memset(&si, 0, sizeof(si)); 1645 1646 if (SCARG(uap, timeout) != NULL) { 1647 struct timespec ts; 1648 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1649 return (error); 1650 #ifdef KTRACE 1651 if (KTRPOINT(p, KTR_STRUCT)) 1652 ktrreltimespec(p, &ts); 1653 #endif 1654 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) 1655 timeinvalid = 1; 1656 else { 1657 to_ticks = (long long)hz * ts.tv_sec + 1658 ts.tv_nsec / (tick * 1000); 1659 if (to_ticks > INT_MAX) 1660 to_ticks = INT_MAX; 1661 } 1662 } 1663 1664 dosigsuspend(p, p->p_sigmask &~ mask); 1665 for (;;) { 1666 si.si_signo = CURSIG(p); 1667 if (si.si_signo != 0) { 1668 sigset_t smask = sigmask(si.si_signo); 1669 if (smask & mask) { 1670 if (p->p_siglist & smask) 1671 m = &p->p_siglist; 1672 else if (pr->ps_mainproc->p_siglist & smask) 1673 m = &pr->ps_mainproc->p_siglist; 1674 else { 1675 /* signal got eaten by someone else? */ 1676 continue; 1677 } 1678 atomic_clearbits_int(m, smask); 1679 error = 0; 1680 break; 1681 } 1682 } 1683 1684 /* per-POSIX, delay this error until after the above */ 1685 if (timeinvalid) 1686 error = EINVAL; 1687 1688 if (error != 0) 1689 break; 1690 1691 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1692 (int)to_ticks); 1693 } 1694 1695 if (error == 0) { 1696 *retval = si.si_signo; 1697 if (SCARG(uap, info) != NULL) 1698 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1699 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1700 /* 1701 * Restarting is wrong if there's a timeout, as it'll be 1702 * for the same interval again 1703 */ 1704 error = EINTR; 1705 } 1706 1707 return (error); 1708 } 1709 1710 void 1711 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1712 { 1713 memset(si, 0, sizeof(*si)); 1714 1715 si->si_signo = sig; 1716 si->si_code = code; 1717 if (code == SI_USER) { 1718 si->si_value = val; 1719 } else { 1720 switch (sig) { 1721 case SIGSEGV: 1722 case SIGILL: 1723 case SIGBUS: 1724 case SIGFPE: 1725 si->si_addr = val.sival_ptr; 1726 si->si_trapno = trapno; 1727 break; 1728 case SIGXFSZ: 1729 break; 1730 } 1731 } 1732 } 1733 1734 int 1735 filt_sigattach(struct knote *kn) 1736 { 1737 struct process *pr = curproc->p_p; 1738 1739 kn->kn_ptr.p_process = pr; 1740 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1741 1742 /* XXX lock the proc here while adding to the list? */ 1743 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1744 1745 return (0); 1746 } 1747 1748 void 1749 filt_sigdetach(struct knote *kn) 1750 { 1751 struct process *pr = kn->kn_ptr.p_process; 1752 1753 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1754 } 1755 1756 /* 1757 * signal knotes are shared with proc knotes, so we apply a mask to 1758 * the hint in order to differentiate them from process hints. This 1759 * could be avoided by using a signal-specific knote list, but probably 1760 * isn't worth the trouble. 1761 */ 1762 int 1763 filt_signal(struct knote *kn, long hint) 1764 { 1765 1766 if (hint & NOTE_SIGNAL) { 1767 hint &= ~NOTE_SIGNAL; 1768 1769 if (kn->kn_id == hint) 1770 kn->kn_data++; 1771 } 1772 return (kn->kn_data != 0); 1773 } 1774 1775 void 1776 userret(struct proc *p) 1777 { 1778 int sig; 1779 1780 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1781 if (p->p_flag & P_PROFPEND) { 1782 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1783 KERNEL_LOCK(); 1784 psignal(p, SIGPROF); 1785 KERNEL_UNLOCK(); 1786 } 1787 if (p->p_flag & P_ALRMPEND) { 1788 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1789 KERNEL_LOCK(); 1790 psignal(p, SIGVTALRM); 1791 KERNEL_UNLOCK(); 1792 } 1793 1794 while ((sig = CURSIG(p)) != 0) 1795 postsig(sig); 1796 1797 /* 1798 * If P_SIGSUSPEND is still set here, then we still need to restore 1799 * the original sigmask before returning to userspace. Also, this 1800 * might unmask some pending signals, so we need to check a second 1801 * time for signals to post. 1802 */ 1803 if (p->p_flag & P_SIGSUSPEND) { 1804 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1805 p->p_sigmask = p->p_oldmask; 1806 1807 while ((sig = CURSIG(p)) != 0) 1808 postsig(sig); 1809 } 1810 1811 if (p->p_flag & P_SUSPSINGLE) { 1812 KERNEL_LOCK(); 1813 single_thread_check(p, 0); 1814 KERNEL_UNLOCK(); 1815 } 1816 1817 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1818 } 1819 1820 int 1821 single_thread_check(struct proc *p, int deep) 1822 { 1823 struct process *pr = p->p_p; 1824 1825 if (pr->ps_single != NULL && pr->ps_single != p) { 1826 do { 1827 int s; 1828 1829 /* if we're in deep, we need to unwind to the edge */ 1830 if (deep) { 1831 if (pr->ps_flags & PS_SINGLEUNWIND) 1832 return (ERESTART); 1833 if (pr->ps_flags & PS_SINGLEEXIT) 1834 return (EINTR); 1835 } 1836 1837 if (--pr->ps_singlecount == 0) 1838 wakeup(&pr->ps_singlecount); 1839 if (pr->ps_flags & PS_SINGLEEXIT) 1840 exit1(p, 0, EXIT_THREAD_NOCHECK); 1841 1842 /* not exiting and don't need to unwind, so suspend */ 1843 SCHED_LOCK(s); 1844 p->p_stat = SSTOP; 1845 mi_switch(); 1846 SCHED_UNLOCK(s); 1847 } while (pr->ps_single != NULL); 1848 } 1849 1850 return (0); 1851 } 1852 1853 /* 1854 * Stop other threads in the process. The mode controls how and 1855 * where the other threads should stop: 1856 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1857 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1858 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1859 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1860 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1861 * or released as with SINGLE_SUSPEND 1862 * - SINGLE_EXIT: unwind to kernel boundary and exit 1863 */ 1864 int 1865 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1866 { 1867 struct process *pr = p->p_p; 1868 struct proc *q; 1869 int error; 1870 1871 KERNEL_ASSERT_LOCKED(); 1872 1873 if ((error = single_thread_check(p, deep))) 1874 return error; 1875 1876 switch (mode) { 1877 case SINGLE_SUSPEND: 1878 case SINGLE_PTRACE: 1879 break; 1880 case SINGLE_UNWIND: 1881 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1882 break; 1883 case SINGLE_EXIT: 1884 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1885 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1886 break; 1887 #ifdef DIAGNOSTIC 1888 default: 1889 panic("single_thread_mode = %d", mode); 1890 #endif 1891 } 1892 pr->ps_single = p; 1893 pr->ps_singlecount = 0; 1894 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1895 int s; 1896 1897 if (q == p) 1898 continue; 1899 if (q->p_flag & P_WEXIT) { 1900 if (mode == SINGLE_EXIT) { 1901 SCHED_LOCK(s); 1902 if (q->p_stat == SSTOP) { 1903 setrunnable(q); 1904 pr->ps_singlecount++; 1905 } 1906 SCHED_UNLOCK(s); 1907 } 1908 continue; 1909 } 1910 SCHED_LOCK(s); 1911 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 1912 switch (q->p_stat) { 1913 case SIDL: 1914 case SRUN: 1915 pr->ps_singlecount++; 1916 break; 1917 case SSLEEP: 1918 /* if it's not interruptible, then just have to wait */ 1919 if (q->p_flag & P_SINTR) { 1920 /* merely need to suspend? just stop it */ 1921 if (mode == SINGLE_SUSPEND || 1922 mode == SINGLE_PTRACE) { 1923 q->p_stat = SSTOP; 1924 break; 1925 } 1926 /* need to unwind or exit, so wake it */ 1927 setrunnable(q); 1928 } 1929 pr->ps_singlecount++; 1930 break; 1931 case SSTOP: 1932 if (mode == SINGLE_EXIT) { 1933 setrunnable(q); 1934 pr->ps_singlecount++; 1935 } 1936 break; 1937 case SDEAD: 1938 break; 1939 case SONPROC: 1940 pr->ps_singlecount++; 1941 signotify(q); 1942 break; 1943 } 1944 SCHED_UNLOCK(s); 1945 } 1946 1947 if (mode != SINGLE_PTRACE) 1948 single_thread_wait(pr); 1949 1950 return 0; 1951 } 1952 1953 void 1954 single_thread_wait(struct process *pr) 1955 { 1956 /* wait until they're all suspended */ 1957 while (pr->ps_singlecount > 0) 1958 tsleep(&pr->ps_singlecount, PUSER, "suspend", 0); 1959 } 1960 1961 void 1962 single_thread_clear(struct proc *p, int flag) 1963 { 1964 struct process *pr = p->p_p; 1965 struct proc *q; 1966 1967 KASSERT(pr->ps_single == p); 1968 KERNEL_ASSERT_LOCKED(); 1969 1970 pr->ps_single = NULL; 1971 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 1972 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1973 int s; 1974 1975 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 1976 continue; 1977 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 1978 1979 /* 1980 * if the thread was only stopped for single threading 1981 * then clearing that either makes it runnable or puts 1982 * it back into some sleep queue 1983 */ 1984 SCHED_LOCK(s); 1985 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 1986 if (q->p_wchan == 0) 1987 setrunnable(q); 1988 else 1989 q->p_stat = SSLEEP; 1990 } 1991 SCHED_UNLOCK(s); 1992 } 1993 } 1994