1 /* $OpenBSD: kern_sig.c,v 1.220 2018/04/28 03:13:04 visa 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/fcntl.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 #include <sys/syslog.h> 65 #include <sys/pledge.h> 66 #include <sys/witness.h> 67 68 #include <sys/mount.h> 69 #include <sys/syscallargs.h> 70 71 #include <uvm/uvm_extern.h> 72 #include <machine/tcb.h> 73 74 int filt_sigattach(struct knote *kn); 75 void filt_sigdetach(struct knote *kn); 76 int filt_signal(struct knote *kn, long hint); 77 78 struct filterops sig_filtops = 79 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 80 81 void proc_stop(struct proc *p, int); 82 void proc_stop_sweep(void *); 83 struct timeout proc_stop_to; 84 85 void postsig(struct proc *, int); 86 int cansignal(struct proc *, struct process *, int); 87 88 struct pool sigacts_pool; /* memory pool for sigacts structures */ 89 90 /* 91 * Can thread p, send the signal signum to process qr? 92 */ 93 int 94 cansignal(struct proc *p, struct process *qr, int signum) 95 { 96 struct process *pr = p->p_p; 97 struct ucred *uc = p->p_ucred; 98 struct ucred *quc = qr->ps_ucred; 99 100 if (uc->cr_uid == 0) 101 return (1); /* root can always signal */ 102 103 if (pr == qr) 104 return (1); /* process can always signal itself */ 105 106 /* optimization: if the same creds then the tests below will pass */ 107 if (uc == quc) 108 return (1); 109 110 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 111 return (1); /* SIGCONT in session */ 112 113 /* 114 * Using kill(), only certain signals can be sent to setugid 115 * child processes 116 */ 117 if (qr->ps_flags & PS_SUGID) { 118 switch (signum) { 119 case 0: 120 case SIGKILL: 121 case SIGINT: 122 case SIGTERM: 123 case SIGALRM: 124 case SIGSTOP: 125 case SIGTTIN: 126 case SIGTTOU: 127 case SIGTSTP: 128 case SIGHUP: 129 case SIGUSR1: 130 case SIGUSR2: 131 if (uc->cr_ruid == quc->cr_ruid || 132 uc->cr_uid == quc->cr_ruid) 133 return (1); 134 } 135 return (0); 136 } 137 138 if (uc->cr_ruid == quc->cr_ruid || 139 uc->cr_ruid == quc->cr_svuid || 140 uc->cr_uid == quc->cr_ruid || 141 uc->cr_uid == quc->cr_svuid) 142 return (1); 143 return (0); 144 } 145 146 /* 147 * Initialize signal-related data structures. 148 */ 149 void 150 signal_init(void) 151 { 152 timeout_set(&proc_stop_to, proc_stop_sweep, NULL); 153 154 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 155 PR_WAITOK, "sigapl", NULL); 156 } 157 158 /* 159 * Create an initial sigacts structure, using the same signal state 160 * as p. 161 */ 162 struct sigacts * 163 sigactsinit(struct process *pr) 164 { 165 struct sigacts *ps; 166 167 ps = pool_get(&sigacts_pool, PR_WAITOK); 168 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 169 ps->ps_refcnt = 1; 170 return (ps); 171 } 172 173 /* 174 * Share a sigacts structure. 175 */ 176 struct sigacts * 177 sigactsshare(struct process *pr) 178 { 179 struct sigacts *ps = pr->ps_sigacts; 180 181 ps->ps_refcnt++; 182 return ps; 183 } 184 185 /* 186 * Initialize a new sigaltstack structure. 187 */ 188 void 189 sigstkinit(struct sigaltstack *ss) 190 { 191 ss->ss_flags = SS_DISABLE; 192 ss->ss_size = 0; 193 ss->ss_sp = 0; 194 } 195 196 /* 197 * Make this process not share its sigacts, maintaining all 198 * signal state. 199 */ 200 void 201 sigactsunshare(struct process *pr) 202 { 203 struct sigacts *newps; 204 205 if (pr->ps_sigacts->ps_refcnt == 1) 206 return; 207 208 newps = sigactsinit(pr); 209 sigactsfree(pr); 210 pr->ps_sigacts = newps; 211 } 212 213 /* 214 * Release a sigacts structure. 215 */ 216 void 217 sigactsfree(struct process *pr) 218 { 219 struct sigacts *ps = pr->ps_sigacts; 220 221 if (--ps->ps_refcnt > 0) 222 return; 223 224 pr->ps_sigacts = NULL; 225 226 pool_put(&sigacts_pool, ps); 227 } 228 229 int 230 sys_sigaction(struct proc *p, void *v, register_t *retval) 231 { 232 struct sys_sigaction_args /* { 233 syscallarg(int) signum; 234 syscallarg(const struct sigaction *) nsa; 235 syscallarg(struct sigaction *) osa; 236 } */ *uap = v; 237 struct sigaction vec; 238 #ifdef KTRACE 239 struct sigaction ovec; 240 #endif 241 struct sigaction *sa; 242 const struct sigaction *nsa; 243 struct sigaction *osa; 244 struct sigacts *ps = p->p_p->ps_sigacts; 245 int signum; 246 int bit, error; 247 248 signum = SCARG(uap, signum); 249 nsa = SCARG(uap, nsa); 250 osa = SCARG(uap, osa); 251 252 if (signum <= 0 || signum >= NSIG || 253 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 254 return (EINVAL); 255 sa = &vec; 256 if (osa) { 257 sa->sa_handler = ps->ps_sigact[signum]; 258 sa->sa_mask = ps->ps_catchmask[signum]; 259 bit = sigmask(signum); 260 sa->sa_flags = 0; 261 if ((ps->ps_sigonstack & bit) != 0) 262 sa->sa_flags |= SA_ONSTACK; 263 if ((ps->ps_sigintr & bit) == 0) 264 sa->sa_flags |= SA_RESTART; 265 if ((ps->ps_sigreset & bit) != 0) 266 sa->sa_flags |= SA_RESETHAND; 267 if ((ps->ps_siginfo & bit) != 0) 268 sa->sa_flags |= SA_SIGINFO; 269 if (signum == SIGCHLD) { 270 if ((ps->ps_flags & SAS_NOCLDSTOP) != 0) 271 sa->sa_flags |= SA_NOCLDSTOP; 272 if ((ps->ps_flags & SAS_NOCLDWAIT) != 0) 273 sa->sa_flags |= SA_NOCLDWAIT; 274 } 275 if ((sa->sa_mask & bit) == 0) 276 sa->sa_flags |= SA_NODEFER; 277 sa->sa_mask &= ~bit; 278 error = copyout(sa, osa, sizeof (vec)); 279 if (error) 280 return (error); 281 #ifdef KTRACE 282 if (KTRPOINT(p, KTR_STRUCT)) 283 ovec = vec; 284 #endif 285 } 286 if (nsa) { 287 error = copyin(nsa, sa, sizeof (vec)); 288 if (error) 289 return (error); 290 #ifdef KTRACE 291 if (KTRPOINT(p, KTR_STRUCT)) 292 ktrsigaction(p, sa); 293 #endif 294 setsigvec(p, signum, sa); 295 } 296 #ifdef KTRACE 297 if (osa && KTRPOINT(p, KTR_STRUCT)) 298 ktrsigaction(p, &ovec); 299 #endif 300 return (0); 301 } 302 303 void 304 setsigvec(struct proc *p, int signum, struct sigaction *sa) 305 { 306 struct sigacts *ps = p->p_p->ps_sigacts; 307 int bit; 308 int s; 309 310 bit = sigmask(signum); 311 /* 312 * Change setting atomically. 313 */ 314 s = splhigh(); 315 ps->ps_sigact[signum] = sa->sa_handler; 316 if ((sa->sa_flags & SA_NODEFER) == 0) 317 sa->sa_mask |= sigmask(signum); 318 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 319 if (signum == SIGCHLD) { 320 if (sa->sa_flags & SA_NOCLDSTOP) 321 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 322 else 323 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 324 /* 325 * If the SA_NOCLDWAIT flag is set or the handler 326 * is SIG_IGN we reparent the dying child to PID 1 327 * (init) which will reap the zombie. Because we use 328 * init to do our dirty work we never set SAS_NOCLDWAIT 329 * for PID 1. 330 * XXX exit1 rework means this is unnecessary? 331 */ 332 if (initprocess->ps_sigacts != ps && 333 ((sa->sa_flags & SA_NOCLDWAIT) || 334 sa->sa_handler == SIG_IGN)) 335 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 336 else 337 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 338 } 339 if ((sa->sa_flags & SA_RESETHAND) != 0) 340 ps->ps_sigreset |= bit; 341 else 342 ps->ps_sigreset &= ~bit; 343 if ((sa->sa_flags & SA_SIGINFO) != 0) 344 ps->ps_siginfo |= bit; 345 else 346 ps->ps_siginfo &= ~bit; 347 if ((sa->sa_flags & SA_RESTART) == 0) 348 ps->ps_sigintr |= bit; 349 else 350 ps->ps_sigintr &= ~bit; 351 if ((sa->sa_flags & SA_ONSTACK) != 0) 352 ps->ps_sigonstack |= bit; 353 else 354 ps->ps_sigonstack &= ~bit; 355 /* 356 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 357 * and for signals set to SIG_DFL where the default is to ignore. 358 * However, don't put SIGCONT in ps_sigignore, 359 * as we have to restart the process. 360 */ 361 if (sa->sa_handler == SIG_IGN || 362 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 363 atomic_clearbits_int(&p->p_siglist, bit); 364 if (signum != SIGCONT) 365 ps->ps_sigignore |= bit; /* easier in psignal */ 366 ps->ps_sigcatch &= ~bit; 367 } else { 368 ps->ps_sigignore &= ~bit; 369 if (sa->sa_handler == SIG_DFL) 370 ps->ps_sigcatch &= ~bit; 371 else 372 ps->ps_sigcatch |= bit; 373 } 374 splx(s); 375 } 376 377 /* 378 * Initialize signal state for process 0; 379 * set to ignore signals that are ignored by default. 380 */ 381 void 382 siginit(struct process *pr) 383 { 384 struct sigacts *ps = pr->ps_sigacts; 385 int i; 386 387 for (i = 0; i < NSIG; i++) 388 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 389 ps->ps_sigignore |= sigmask(i); 390 ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 391 } 392 393 /* 394 * Reset signals for an exec by the specified thread. 395 */ 396 void 397 execsigs(struct proc *p) 398 { 399 struct sigacts *ps; 400 int nc, mask; 401 402 sigactsunshare(p->p_p); 403 ps = p->p_p->ps_sigacts; 404 405 /* 406 * Reset caught signals. Held signals remain held 407 * through p_sigmask (unless they were caught, 408 * and are now ignored by default). 409 */ 410 while (ps->ps_sigcatch) { 411 nc = ffs((long)ps->ps_sigcatch); 412 mask = sigmask(nc); 413 ps->ps_sigcatch &= ~mask; 414 if (sigprop[nc] & SA_IGNORE) { 415 if (nc != SIGCONT) 416 ps->ps_sigignore |= mask; 417 atomic_clearbits_int(&p->p_siglist, mask); 418 } 419 ps->ps_sigact[nc] = SIG_DFL; 420 } 421 /* 422 * Reset stack state to the user stack. 423 * Clear set of signals caught on the signal stack. 424 */ 425 sigstkinit(&p->p_sigstk); 426 ps->ps_flags &= ~SAS_NOCLDWAIT; 427 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 428 ps->ps_sigact[SIGCHLD] = SIG_DFL; 429 } 430 431 /* 432 * Manipulate signal mask. 433 * Note that we receive new mask, not pointer, 434 * and return old mask as return value; 435 * the library stub does the rest. 436 */ 437 int 438 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 439 { 440 struct sys_sigprocmask_args /* { 441 syscallarg(int) how; 442 syscallarg(sigset_t) mask; 443 } */ *uap = v; 444 int error = 0; 445 sigset_t mask; 446 447 *retval = p->p_sigmask; 448 mask = SCARG(uap, mask) &~ sigcantmask; 449 450 switch (SCARG(uap, how)) { 451 case SIG_BLOCK: 452 atomic_setbits_int(&p->p_sigmask, mask); 453 break; 454 case SIG_UNBLOCK: 455 atomic_clearbits_int(&p->p_sigmask, mask); 456 break; 457 case SIG_SETMASK: 458 p->p_sigmask = mask; 459 break; 460 default: 461 error = EINVAL; 462 break; 463 } 464 return (error); 465 } 466 467 int 468 sys_sigpending(struct proc *p, void *v, register_t *retval) 469 { 470 471 *retval = p->p_siglist; 472 return (0); 473 } 474 475 /* 476 * Temporarily replace calling proc's signal mask for the duration of a 477 * system call. Original signal mask will be restored by userret(). 478 */ 479 void 480 dosigsuspend(struct proc *p, sigset_t newmask) 481 { 482 KASSERT(p == curproc); 483 484 p->p_oldmask = p->p_sigmask; 485 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 486 p->p_sigmask = newmask; 487 } 488 489 /* 490 * Suspend process until signal, providing mask to be set 491 * in the meantime. Note nonstandard calling convention: 492 * libc stub passes mask, not pointer, to save a copyin. 493 */ 494 int 495 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 496 { 497 struct sys_sigsuspend_args /* { 498 syscallarg(int) mask; 499 } */ *uap = v; 500 struct process *pr = p->p_p; 501 struct sigacts *ps = pr->ps_sigacts; 502 503 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 504 while (tsleep(ps, PPAUSE|PCATCH, "pause", 0) == 0) 505 /* void */; 506 /* always return EINTR rather than ERESTART... */ 507 return (EINTR); 508 } 509 510 int 511 sigonstack(size_t stack) 512 { 513 const struct sigaltstack *ss = &curproc->p_sigstk; 514 515 return (ss->ss_flags & SS_DISABLE ? 0 : 516 (stack - (size_t)ss->ss_sp < ss->ss_size)); 517 } 518 519 int 520 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 521 { 522 struct sys_sigaltstack_args /* { 523 syscallarg(const struct sigaltstack *) nss; 524 syscallarg(struct sigaltstack *) oss; 525 } */ *uap = v; 526 struct sigaltstack ss; 527 const struct sigaltstack *nss; 528 struct sigaltstack *oss; 529 int onstack = sigonstack(PROC_STACK(p)); 530 int error; 531 532 nss = SCARG(uap, nss); 533 oss = SCARG(uap, oss); 534 535 if (oss != NULL) { 536 ss = p->p_sigstk; 537 if (onstack) 538 ss.ss_flags |= SS_ONSTACK; 539 if ((error = copyout(&ss, oss, sizeof(ss)))) 540 return (error); 541 } 542 if (nss == NULL) 543 return (0); 544 error = copyin(nss, &ss, sizeof(ss)); 545 if (error) 546 return (error); 547 if (onstack) 548 return (EPERM); 549 if (ss.ss_flags & ~SS_DISABLE) 550 return (EINVAL); 551 if (ss.ss_flags & SS_DISABLE) { 552 p->p_sigstk.ss_flags = ss.ss_flags; 553 return (0); 554 } 555 if (ss.ss_size < MINSIGSTKSZ) 556 return (ENOMEM); 557 558 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 559 if (error) 560 return (error); 561 562 p->p_sigstk = ss; 563 return (0); 564 } 565 566 int 567 sys_kill(struct proc *cp, void *v, register_t *retval) 568 { 569 struct sys_kill_args /* { 570 syscallarg(int) pid; 571 syscallarg(int) signum; 572 } */ *uap = v; 573 struct process *pr; 574 int pid = SCARG(uap, pid); 575 int signum = SCARG(uap, signum); 576 int error; 577 int zombie = 0; 578 579 if ((error = pledge_kill(cp, pid)) != 0) 580 return (error); 581 if (((u_int)signum) >= NSIG) 582 return (EINVAL); 583 if (pid > 0) { 584 if ((pr = prfind(pid)) == NULL) { 585 if ((pr = zombiefind(pid)) == NULL) 586 return (ESRCH); 587 else 588 zombie = 1; 589 } 590 if (!cansignal(cp, pr, signum)) 591 return (EPERM); 592 593 /* kill single process */ 594 if (signum && !zombie) 595 prsignal(pr, signum); 596 return (0); 597 } 598 switch (pid) { 599 case -1: /* broadcast signal */ 600 return (killpg1(cp, signum, 0, 1)); 601 case 0: /* signal own process group */ 602 return (killpg1(cp, signum, 0, 0)); 603 default: /* negative explicit process group */ 604 return (killpg1(cp, signum, -pid, 0)); 605 } 606 } 607 608 int 609 sys_thrkill(struct proc *cp, void *v, register_t *retval) 610 { 611 struct sys_thrkill_args /* { 612 syscallarg(pid_t) tid; 613 syscallarg(int) signum; 614 syscallarg(void *) tcb; 615 } */ *uap = v; 616 struct proc *p; 617 int tid = SCARG(uap, tid); 618 int signum = SCARG(uap, signum); 619 void *tcb; 620 621 if (((u_int)signum) >= NSIG) 622 return (EINVAL); 623 if (tid > THREAD_PID_OFFSET) { 624 if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL) 625 return (ESRCH); 626 627 /* can only kill threads in the same process */ 628 if (p->p_p != cp->p_p) 629 return (ESRCH); 630 } else if (tid == 0) 631 p = cp; 632 else 633 return (EINVAL); 634 635 /* optionally require the target thread to have the given tcb addr */ 636 tcb = SCARG(uap, tcb); 637 if (tcb != NULL && tcb != TCB_GET(p)) 638 return (ESRCH); 639 640 if (signum) 641 ptsignal(p, signum, STHREAD); 642 return (0); 643 } 644 645 /* 646 * Common code for kill process group/broadcast kill. 647 * cp is calling process. 648 */ 649 int 650 killpg1(struct proc *cp, int signum, int pgid, int all) 651 { 652 struct process *pr; 653 struct pgrp *pgrp; 654 int nfound = 0; 655 656 if (all) { 657 /* 658 * broadcast 659 */ 660 LIST_FOREACH(pr, &allprocess, ps_list) { 661 if (pr->ps_pid <= 1 || 662 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 663 pr == cp->p_p || !cansignal(cp, pr, signum)) 664 continue; 665 nfound++; 666 if (signum) 667 prsignal(pr, signum); 668 } 669 } else { 670 if (pgid == 0) 671 /* 672 * zero pgid means send to my process group. 673 */ 674 pgrp = cp->p_p->ps_pgrp; 675 else { 676 pgrp = pgfind(pgid); 677 if (pgrp == NULL) 678 return (ESRCH); 679 } 680 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 681 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 682 !cansignal(cp, pr, signum)) 683 continue; 684 nfound++; 685 if (signum) 686 prsignal(pr, signum); 687 } 688 } 689 return (nfound ? 0 : ESRCH); 690 } 691 692 #define CANDELIVER(uid, euid, pr) \ 693 (euid == 0 || \ 694 (uid) == (pr)->ps_ucred->cr_ruid || \ 695 (uid) == (pr)->ps_ucred->cr_svuid || \ 696 (uid) == (pr)->ps_ucred->cr_uid || \ 697 (euid) == (pr)->ps_ucred->cr_ruid || \ 698 (euid) == (pr)->ps_ucred->cr_svuid || \ 699 (euid) == (pr)->ps_ucred->cr_uid) 700 701 /* 702 * Deliver signum to pgid, but first check uid/euid against each 703 * process and see if it is permitted. 704 */ 705 void 706 csignal(pid_t pgid, int signum, uid_t uid, uid_t euid) 707 { 708 struct pgrp *pgrp; 709 struct process *pr; 710 711 if (pgid == 0) 712 return; 713 if (pgid < 0) { 714 pgid = -pgid; 715 if ((pgrp = pgfind(pgid)) == NULL) 716 return; 717 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 718 if (CANDELIVER(uid, euid, pr)) 719 prsignal(pr, signum); 720 } else { 721 if ((pr = prfind(pgid)) == NULL) 722 return; 723 if (CANDELIVER(uid, euid, pr)) 724 prsignal(pr, signum); 725 } 726 } 727 728 /* 729 * Send a signal to a process group. 730 */ 731 void 732 gsignal(int pgid, int signum) 733 { 734 struct pgrp *pgrp; 735 736 if (pgid && (pgrp = pgfind(pgid))) 737 pgsignal(pgrp, signum, 0); 738 } 739 740 /* 741 * Send a signal to a process group. If checktty is 1, 742 * limit to members which have a controlling terminal. 743 */ 744 void 745 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 746 { 747 struct process *pr; 748 749 if (pgrp) 750 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 751 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 752 prsignal(pr, signum); 753 } 754 755 /* 756 * Recalculate the signal mask and reset the signal disposition after 757 * usermode frame for delivery is formed. 758 */ 759 void 760 postsig_done(struct proc *p, int signum, struct sigacts *ps) 761 { 762 int mask = sigmask(signum); 763 764 KERNEL_ASSERT_LOCKED(); 765 766 p->p_ru.ru_nsignals++; 767 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 768 if ((ps->ps_sigreset & mask) != 0) { 769 ps->ps_sigcatch &= ~mask; 770 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 771 ps->ps_sigignore |= mask; 772 ps->ps_sigact[signum] = SIG_DFL; 773 } 774 } 775 776 /* 777 * Send a signal caused by a trap to the current thread 778 * If it will be caught immediately, deliver it with correct code. 779 * Otherwise, post it normally. 780 */ 781 void 782 trapsignal(struct proc *p, int signum, u_long trapno, int code, 783 union sigval sigval) 784 { 785 struct process *pr = p->p_p; 786 struct sigacts *ps = pr->ps_sigacts; 787 int mask; 788 789 switch (signum) { 790 case SIGILL: 791 case SIGBUS: 792 case SIGSEGV: 793 pr->ps_acflag |= ATRAP; 794 break; 795 } 796 797 mask = sigmask(signum); 798 if ((pr->ps_flags & PS_TRACED) == 0 && 799 (ps->ps_sigcatch & mask) != 0 && 800 (p->p_sigmask & mask) == 0) { 801 #ifdef KTRACE 802 if (KTRPOINT(p, KTR_PSIG)) { 803 siginfo_t si; 804 805 initsiginfo(&si, signum, trapno, code, sigval); 806 ktrpsig(p, signum, ps->ps_sigact[signum], 807 p->p_sigmask, code, &si); 808 } 809 #endif 810 (*pr->ps_emul->e_sendsig)(ps->ps_sigact[signum], signum, 811 p->p_sigmask, trapno, code, sigval); 812 postsig_done(p, signum, ps); 813 } else { 814 p->p_sisig = signum; 815 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 816 p->p_sicode = code; 817 p->p_sigval = sigval; 818 819 /* 820 * Signals like SIGBUS and SIGSEGV should not, when 821 * generated by the kernel, be ignorable or blockable. 822 * If it is and we're not being traced, then just kill 823 * the process. 824 */ 825 if ((pr->ps_flags & PS_TRACED) == 0 && 826 (sigprop[signum] & SA_KILL) && 827 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 828 sigexit(p, signum); 829 ptsignal(p, signum, STHREAD); 830 } 831 } 832 833 /* 834 * Send the signal to the process. If the signal has an action, the action 835 * is usually performed by the target process rather than the caller; we add 836 * the signal to the set of pending signals for the process. 837 * 838 * Exceptions: 839 * o When a stop signal is sent to a sleeping process that takes the 840 * default action, the process is stopped without awakening it. 841 * o SIGCONT restarts stopped processes (or puts them back to sleep) 842 * regardless of the signal action (eg, blocked or ignored). 843 * 844 * Other ignored signals are discarded immediately. 845 */ 846 void 847 psignal(struct proc *p, int signum) 848 { 849 ptsignal(p, signum, SPROCESS); 850 } 851 852 /* 853 * type = SPROCESS process signal, can be diverted (sigwait()) 854 * XXX if blocked in all threads, mark as pending in struct process 855 * type = STHREAD thread signal, but should be propagated if unhandled 856 * type = SPROPAGATED propagated to this thread, so don't propagate again 857 */ 858 void 859 ptsignal(struct proc *p, int signum, enum signal_type type) 860 { 861 int s, prop; 862 sig_t action; 863 int mask; 864 struct process *pr = p->p_p; 865 struct proc *q; 866 int wakeparent = 0; 867 868 #ifdef DIAGNOSTIC 869 if ((u_int)signum >= NSIG || signum == 0) 870 panic("psignal signal number"); 871 #endif 872 873 /* Ignore signal if the target process is exiting */ 874 if (pr->ps_flags & PS_EXITING) 875 return; 876 877 mask = sigmask(signum); 878 879 if (type == SPROCESS) { 880 /* Accept SIGKILL to coredumping processes */ 881 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 882 if (pr->ps_single != NULL) 883 p = pr->ps_single; 884 atomic_setbits_int(&p->p_siglist, mask); 885 return; 886 } 887 888 /* 889 * If the current thread can process the signal 890 * immediately (it's unblocked) then have it take it. 891 */ 892 q = curproc; 893 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 894 (q->p_sigmask & mask) == 0) 895 p = q; 896 else { 897 /* 898 * A process-wide signal can be diverted to a 899 * different thread that's in sigwait() for this 900 * signal. If there isn't such a thread, then 901 * pick a thread that doesn't have it blocked so 902 * that the stop/kill consideration isn't 903 * delayed. Otherwise, mark it pending on the 904 * main thread. 905 */ 906 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 907 /* ignore exiting threads */ 908 if (q->p_flag & P_WEXIT) 909 continue; 910 911 /* skip threads that have the signal blocked */ 912 if ((q->p_sigmask & mask) != 0) 913 continue; 914 915 /* okay, could send to this thread */ 916 p = q; 917 918 /* 919 * sigsuspend, sigwait, ppoll/pselect, etc? 920 * Definitely go to this thread, as it's 921 * already blocked in the kernel. 922 */ 923 if (q->p_flag & P_SIGSUSPEND) 924 break; 925 } 926 } 927 } 928 929 if (type != SPROPAGATED) 930 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 931 932 prop = sigprop[signum]; 933 934 /* 935 * If proc is traced, always give parent a chance. 936 */ 937 if (pr->ps_flags & PS_TRACED) { 938 action = SIG_DFL; 939 atomic_setbits_int(&p->p_siglist, mask); 940 } else { 941 /* 942 * If the signal is being ignored, 943 * then we forget about it immediately. 944 * (Note: we don't set SIGCONT in ps_sigignore, 945 * and if it is set to SIG_IGN, 946 * action will be SIG_DFL here.) 947 */ 948 if (pr->ps_sigacts->ps_sigignore & mask) 949 return; 950 if (p->p_sigmask & mask) { 951 action = SIG_HOLD; 952 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 953 action = SIG_CATCH; 954 } else { 955 action = SIG_DFL; 956 957 if (prop & SA_KILL && pr->ps_nice > NZERO) 958 pr->ps_nice = NZERO; 959 960 /* 961 * If sending a tty stop signal to a member of an 962 * orphaned process group, discard the signal here if 963 * the action is default; don't stop the process below 964 * if sleeping, and don't clear any pending SIGCONT. 965 */ 966 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 967 return; 968 } 969 970 atomic_setbits_int(&p->p_siglist, mask); 971 } 972 973 if (prop & SA_CONT) 974 atomic_clearbits_int(&p->p_siglist, stopsigmask); 975 976 if (prop & SA_STOP) { 977 atomic_clearbits_int(&p->p_siglist, contsigmask); 978 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 979 } 980 981 /* 982 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 983 */ 984 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 985 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 986 if (q != p) 987 ptsignal(q, signum, SPROPAGATED); 988 989 /* 990 * Defer further processing for signals which are held, 991 * except that stopped processes must be continued by SIGCONT. 992 */ 993 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 994 return; 995 996 SCHED_LOCK(s); 997 998 switch (p->p_stat) { 999 1000 case SSLEEP: 1001 /* 1002 * If process is sleeping uninterruptibly 1003 * we can't interrupt the sleep... the signal will 1004 * be noticed when the process returns through 1005 * trap() or syscall(). 1006 */ 1007 if ((p->p_flag & P_SINTR) == 0) 1008 goto out; 1009 /* 1010 * Process is sleeping and traced... make it runnable 1011 * so it can discover the signal in issignal() and stop 1012 * for the parent. 1013 */ 1014 if (pr->ps_flags & PS_TRACED) 1015 goto run; 1016 /* 1017 * If SIGCONT is default (or ignored) and process is 1018 * asleep, we are finished; the process should not 1019 * be awakened. 1020 */ 1021 if ((prop & SA_CONT) && action == SIG_DFL) { 1022 atomic_clearbits_int(&p->p_siglist, mask); 1023 goto out; 1024 } 1025 /* 1026 * When a sleeping process receives a stop 1027 * signal, process immediately if possible. 1028 */ 1029 if ((prop & SA_STOP) && action == SIG_DFL) { 1030 /* 1031 * If a child holding parent blocked, 1032 * stopping could cause deadlock. 1033 */ 1034 if (pr->ps_flags & PS_PPWAIT) 1035 goto out; 1036 atomic_clearbits_int(&p->p_siglist, mask); 1037 p->p_xstat = signum; 1038 proc_stop(p, 0); 1039 goto out; 1040 } 1041 /* 1042 * All other (caught or default) signals 1043 * cause the process to run. 1044 */ 1045 goto runfast; 1046 /*NOTREACHED*/ 1047 1048 case SSTOP: 1049 /* 1050 * If traced process is already stopped, 1051 * then no further action is necessary. 1052 */ 1053 if (pr->ps_flags & PS_TRACED) 1054 goto out; 1055 1056 /* 1057 * Kill signal always sets processes running. 1058 */ 1059 if (signum == SIGKILL) { 1060 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1061 goto runfast; 1062 } 1063 1064 if (prop & SA_CONT) { 1065 /* 1066 * If SIGCONT is default (or ignored), we continue the 1067 * process but don't leave the signal in p_siglist, as 1068 * it has no further action. If SIGCONT is held, we 1069 * continue the process and leave the signal in 1070 * p_siglist. If the process catches SIGCONT, let it 1071 * handle the signal itself. If it isn't waiting on 1072 * an event, then it goes back to run state. 1073 * Otherwise, process goes back to sleep state. 1074 */ 1075 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1076 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1077 wakeparent = 1; 1078 if (action == SIG_DFL) 1079 atomic_clearbits_int(&p->p_siglist, mask); 1080 if (action == SIG_CATCH) 1081 goto runfast; 1082 if (p->p_wchan == 0) 1083 goto run; 1084 p->p_stat = SSLEEP; 1085 goto out; 1086 } 1087 1088 if (prop & SA_STOP) { 1089 /* 1090 * Already stopped, don't need to stop again. 1091 * (If we did the shell could get confused.) 1092 */ 1093 atomic_clearbits_int(&p->p_siglist, mask); 1094 goto out; 1095 } 1096 1097 /* 1098 * If process is sleeping interruptibly, then simulate a 1099 * wakeup so that when it is continued, it will be made 1100 * runnable and can look at the signal. But don't make 1101 * the process runnable, leave it stopped. 1102 */ 1103 if (p->p_wchan && p->p_flag & P_SINTR) 1104 unsleep(p); 1105 goto out; 1106 1107 case SONPROC: 1108 signotify(p); 1109 /* FALLTHROUGH */ 1110 default: 1111 /* 1112 * SRUN, SIDL, SDEAD do nothing with the signal, 1113 * other than kicking ourselves if we are running. 1114 * It will either never be noticed, or noticed very soon. 1115 */ 1116 goto out; 1117 } 1118 /*NOTREACHED*/ 1119 1120 runfast: 1121 /* 1122 * Raise priority to at least PUSER. 1123 */ 1124 if (p->p_priority > PUSER) 1125 p->p_priority = PUSER; 1126 run: 1127 setrunnable(p); 1128 out: 1129 SCHED_UNLOCK(s); 1130 if (wakeparent) 1131 wakeup(pr->ps_pptr); 1132 } 1133 1134 /* 1135 * If the current process has received a signal (should be caught or cause 1136 * termination, should interrupt current syscall), return the signal number. 1137 * Stop signals with default action are processed immediately, then cleared; 1138 * they aren't returned. This is checked after each entry to the system for 1139 * a syscall or trap (though this can usually be done without calling issignal 1140 * by checking the pending signal masks in the CURSIG macro.) The normal call 1141 * sequence is 1142 * 1143 * while (signum = CURSIG(curproc)) 1144 * postsig(signum); 1145 * 1146 * Assumes that if the P_SINTR flag is set, we're holding both the 1147 * kernel and scheduler locks. 1148 */ 1149 int 1150 issignal(struct proc *p) 1151 { 1152 struct process *pr = p->p_p; 1153 int signum, mask, prop; 1154 int dolock = (p->p_flag & P_SINTR) == 0; 1155 int s; 1156 1157 for (;;) { 1158 mask = p->p_siglist & ~p->p_sigmask; 1159 if (pr->ps_flags & PS_PPWAIT) 1160 mask &= ~stopsigmask; 1161 if (mask == 0) /* no signal to send */ 1162 return (0); 1163 signum = ffs((long)mask); 1164 mask = sigmask(signum); 1165 atomic_clearbits_int(&p->p_siglist, mask); 1166 1167 /* 1168 * We should see pending but ignored signals 1169 * only if PS_TRACED was on when they were posted. 1170 */ 1171 if (mask & pr->ps_sigacts->ps_sigignore && 1172 (pr->ps_flags & PS_TRACED) == 0) 1173 continue; 1174 1175 /* 1176 * If traced, always stop, and stay stopped until released 1177 * by the debugger. If our parent process is waiting for 1178 * us, don't hang as we could deadlock. 1179 */ 1180 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1181 signum != SIGKILL) { 1182 p->p_xstat = signum; 1183 1184 if (dolock) 1185 KERNEL_LOCK(); 1186 single_thread_set(p, SINGLE_PTRACE, 0); 1187 if (dolock) 1188 KERNEL_UNLOCK(); 1189 1190 if (dolock) 1191 SCHED_LOCK(s); 1192 proc_stop(p, 1); 1193 if (dolock) 1194 SCHED_UNLOCK(s); 1195 1196 if (dolock) 1197 KERNEL_LOCK(); 1198 single_thread_clear(p, 0); 1199 if (dolock) 1200 KERNEL_UNLOCK(); 1201 1202 /* 1203 * If we are no longer being traced, or the parent 1204 * didn't give us a signal, look for more signals. 1205 */ 1206 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1207 continue; 1208 1209 /* 1210 * If the new signal is being masked, look for other 1211 * signals. 1212 */ 1213 signum = p->p_xstat; 1214 mask = sigmask(signum); 1215 if ((p->p_sigmask & mask) != 0) 1216 continue; 1217 1218 /* take the signal! */ 1219 atomic_clearbits_int(&p->p_siglist, mask); 1220 } 1221 1222 prop = sigprop[signum]; 1223 1224 /* 1225 * Decide whether the signal should be returned. 1226 * Return the signal's number, or fall through 1227 * to clear it from the pending mask. 1228 */ 1229 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1230 case (long)SIG_DFL: 1231 /* 1232 * Don't take default actions on system processes. 1233 */ 1234 if (pr->ps_pid <= 1) { 1235 #ifdef DIAGNOSTIC 1236 /* 1237 * Are you sure you want to ignore SIGSEGV 1238 * in init? XXX 1239 */ 1240 printf("Process (pid %d) got signal" 1241 " %d\n", pr->ps_pid, signum); 1242 #endif 1243 break; /* == ignore */ 1244 } 1245 /* 1246 * If there is a pending stop signal to process 1247 * with default action, stop here, 1248 * then clear the signal. However, 1249 * if process is member of an orphaned 1250 * process group, ignore tty stop signals. 1251 */ 1252 if (prop & SA_STOP) { 1253 if (pr->ps_flags & PS_TRACED || 1254 (pr->ps_pgrp->pg_jobc == 0 && 1255 prop & SA_TTYSTOP)) 1256 break; /* == ignore */ 1257 p->p_xstat = signum; 1258 if (dolock) 1259 SCHED_LOCK(s); 1260 proc_stop(p, 1); 1261 if (dolock) 1262 SCHED_UNLOCK(s); 1263 break; 1264 } else if (prop & SA_IGNORE) { 1265 /* 1266 * Except for SIGCONT, shouldn't get here. 1267 * Default action is to ignore; drop it. 1268 */ 1269 break; /* == ignore */ 1270 } else 1271 goto keep; 1272 /*NOTREACHED*/ 1273 case (long)SIG_IGN: 1274 /* 1275 * Masking above should prevent us ever trying 1276 * to take action on an ignored signal other 1277 * than SIGCONT, unless process is traced. 1278 */ 1279 if ((prop & SA_CONT) == 0 && 1280 (pr->ps_flags & PS_TRACED) == 0) 1281 printf("issignal\n"); 1282 break; /* == ignore */ 1283 default: 1284 /* 1285 * This signal has an action, let 1286 * postsig() process it. 1287 */ 1288 goto keep; 1289 } 1290 } 1291 /* NOTREACHED */ 1292 1293 keep: 1294 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1295 return (signum); 1296 } 1297 1298 /* 1299 * Put the argument process into the stopped state and notify the parent 1300 * via wakeup. Signals are handled elsewhere. The process must not be 1301 * on the run queue. 1302 */ 1303 void 1304 proc_stop(struct proc *p, int sw) 1305 { 1306 struct process *pr = p->p_p; 1307 extern void *softclock_si; 1308 1309 #ifdef MULTIPROCESSOR 1310 SCHED_ASSERT_LOCKED(); 1311 #endif 1312 1313 p->p_stat = SSTOP; 1314 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1315 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1316 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1317 if (!timeout_pending(&proc_stop_to)) { 1318 timeout_add(&proc_stop_to, 0); 1319 /* 1320 * We need this soft interrupt to be handled fast. 1321 * Extra calls to softclock don't hurt. 1322 */ 1323 softintr_schedule(softclock_si); 1324 } 1325 if (sw) 1326 mi_switch(); 1327 } 1328 1329 /* 1330 * Called from a timeout to send signals to the parents of stopped processes. 1331 * We can't do this in proc_stop because it's called with nasty locks held 1332 * and we would need recursive scheduler lock to deal with that. 1333 */ 1334 void 1335 proc_stop_sweep(void *v) 1336 { 1337 struct process *pr; 1338 1339 LIST_FOREACH(pr, &allprocess, ps_list) { 1340 if ((pr->ps_flags & PS_STOPPED) == 0) 1341 continue; 1342 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1343 1344 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1345 prsignal(pr->ps_pptr, SIGCHLD); 1346 wakeup(pr->ps_pptr); 1347 } 1348 } 1349 1350 /* 1351 * Take the action for the specified signal 1352 * from the current set of pending signals. 1353 */ 1354 void 1355 postsig(struct proc *p, int signum) 1356 { 1357 struct process *pr = p->p_p; 1358 struct sigacts *ps = pr->ps_sigacts; 1359 sig_t action; 1360 u_long trapno; 1361 int mask, returnmask; 1362 union sigval sigval; 1363 int s, code; 1364 1365 KASSERT(signum != 0); 1366 KERNEL_ASSERT_LOCKED(); 1367 1368 mask = sigmask(signum); 1369 atomic_clearbits_int(&p->p_siglist, mask); 1370 action = ps->ps_sigact[signum]; 1371 sigval.sival_ptr = 0; 1372 1373 if (p->p_sisig != signum) { 1374 trapno = 0; 1375 code = SI_USER; 1376 sigval.sival_ptr = 0; 1377 } else { 1378 trapno = p->p_sitrapno; 1379 code = p->p_sicode; 1380 sigval = p->p_sigval; 1381 } 1382 1383 #ifdef KTRACE 1384 if (KTRPOINT(p, KTR_PSIG)) { 1385 siginfo_t si; 1386 1387 initsiginfo(&si, signum, trapno, code, sigval); 1388 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1389 p->p_oldmask : p->p_sigmask, code, &si); 1390 } 1391 #endif 1392 if (action == SIG_DFL) { 1393 /* 1394 * Default action, where the default is to kill 1395 * the process. (Other cases were ignored above.) 1396 */ 1397 sigexit(p, signum); 1398 /* NOTREACHED */ 1399 } else { 1400 /* 1401 * If we get here, the signal must be caught. 1402 */ 1403 #ifdef DIAGNOSTIC 1404 if (action == SIG_IGN || (p->p_sigmask & mask)) 1405 panic("postsig action"); 1406 #endif 1407 /* 1408 * Set the new mask value and also defer further 1409 * occurrences of this signal. 1410 * 1411 * Special case: user has done a sigpause. Here the 1412 * current mask is not of interest, but rather the 1413 * mask from before the sigpause is what we want 1414 * restored after the signal processing is completed. 1415 */ 1416 #ifdef MULTIPROCESSOR 1417 s = splsched(); 1418 #else 1419 s = splhigh(); 1420 #endif 1421 if (p->p_flag & P_SIGSUSPEND) { 1422 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1423 returnmask = p->p_oldmask; 1424 } else { 1425 returnmask = p->p_sigmask; 1426 } 1427 if (p->p_sisig == signum) { 1428 p->p_sisig = 0; 1429 p->p_sitrapno = 0; 1430 p->p_sicode = SI_USER; 1431 p->p_sigval.sival_ptr = NULL; 1432 } 1433 1434 (*pr->ps_emul->e_sendsig)(action, signum, returnmask, trapno, 1435 code, sigval); 1436 postsig_done(p, signum, ps); 1437 splx(s); 1438 } 1439 } 1440 1441 /* 1442 * Force the current process to exit with the specified signal, dumping core 1443 * if appropriate. We bypass the normal tests for masked and caught signals, 1444 * allowing unrecoverable failures to terminate the process without changing 1445 * signal state. Mark the accounting record with the signal termination. 1446 * If dumping core, save the signal number for the debugger. Calls exit and 1447 * does not return. 1448 */ 1449 void 1450 sigexit(struct proc *p, int signum) 1451 { 1452 /* Mark process as going away */ 1453 atomic_setbits_int(&p->p_flag, P_WEXIT); 1454 1455 p->p_p->ps_acflag |= AXSIG; 1456 if (sigprop[signum] & SA_CORE) { 1457 p->p_sisig = signum; 1458 1459 /* if there are other threads, pause them */ 1460 if (P_HASSIBLING(p)) 1461 single_thread_set(p, SINGLE_SUSPEND, 0); 1462 1463 if (coredump(p) == 0) 1464 signum |= WCOREFLAG; 1465 } 1466 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1467 /* NOTREACHED */ 1468 } 1469 1470 int nosuidcoredump = 1; 1471 1472 struct coredump_iostate { 1473 struct proc *io_proc; 1474 struct vnode *io_vp; 1475 struct ucred *io_cred; 1476 off_t io_offset; 1477 }; 1478 1479 /* 1480 * Dump core, into a file named "progname.core", unless the process was 1481 * setuid/setgid. 1482 */ 1483 int 1484 coredump(struct proc *p) 1485 { 1486 #ifdef SMALL_KERNEL 1487 return EPERM; 1488 #else 1489 struct process *pr = p->p_p; 1490 struct vnode *vp; 1491 struct ucred *cred = p->p_ucred; 1492 struct vmspace *vm = p->p_vmspace; 1493 struct nameidata nd; 1494 struct vattr vattr; 1495 struct coredump_iostate io; 1496 int error, len, incrash = 0; 1497 char name[MAXPATHLEN]; 1498 const char *dir = "/var/crash"; 1499 1500 if (pr->ps_emul->e_coredump == NULL) 1501 return (EINVAL); 1502 1503 pr->ps_flags |= PS_COREDUMP; 1504 1505 /* 1506 * If the process has inconsistent uids, nosuidcoredump 1507 * determines coredump placement policy. 1508 */ 1509 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1510 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1511 if (nosuidcoredump == 3 || nosuidcoredump == 2) 1512 incrash = 1; 1513 else 1514 return (EPERM); 1515 } 1516 1517 /* Don't dump if will exceed file size limit. */ 1518 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= 1519 p->p_rlimit[RLIMIT_CORE].rlim_cur) 1520 return (EFBIG); 1521 1522 if (incrash && nosuidcoredump == 3) { 1523 /* 1524 * If the program directory does not exist, dumps of 1525 * that core will silently fail. 1526 */ 1527 len = snprintf(name, sizeof(name), "%s/%s/%u.core", 1528 dir, pr->ps_comm, pr->ps_pid); 1529 } else if (incrash && nosuidcoredump == 2) 1530 len = snprintf(name, sizeof(name), "%s/%s.core", 1531 dir, pr->ps_comm); 1532 else 1533 len = snprintf(name, sizeof(name), "%s.core", pr->ps_comm); 1534 if (len >= sizeof(name)) 1535 return (EACCES); 1536 1537 /* 1538 * Control the UID used to write out. The normal case uses 1539 * the real UID. If the sugid case is going to write into the 1540 * controlled directory, we do so as root. 1541 */ 1542 if (incrash == 0) { 1543 cred = crdup(cred); 1544 cred->cr_uid = cred->cr_ruid; 1545 cred->cr_gid = cred->cr_rgid; 1546 } else { 1547 if (p->p_fd->fd_rdir) { 1548 vrele(p->p_fd->fd_rdir); 1549 p->p_fd->fd_rdir = NULL; 1550 } 1551 p->p_ucred = crdup(p->p_ucred); 1552 crfree(cred); 1553 cred = p->p_ucred; 1554 crhold(cred); 1555 cred->cr_uid = 0; 1556 cred->cr_gid = 0; 1557 } 1558 1559 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1560 1561 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1562 1563 if (error) 1564 goto out; 1565 1566 /* 1567 * Don't dump to non-regular files, files with links, or files 1568 * owned by someone else. 1569 */ 1570 vp = nd.ni_vp; 1571 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1572 VOP_UNLOCK(vp); 1573 vn_close(vp, FWRITE, cred, p); 1574 goto out; 1575 } 1576 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1577 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1578 vattr.va_uid != cred->cr_uid) { 1579 error = EACCES; 1580 VOP_UNLOCK(vp); 1581 vn_close(vp, FWRITE, cred, p); 1582 goto out; 1583 } 1584 VATTR_NULL(&vattr); 1585 vattr.va_size = 0; 1586 VOP_SETATTR(vp, &vattr, cred, p); 1587 pr->ps_acflag |= ACORE; 1588 1589 io.io_proc = p; 1590 io.io_vp = vp; 1591 io.io_cred = cred; 1592 io.io_offset = 0; 1593 VOP_UNLOCK(vp); 1594 vref(vp); 1595 error = vn_close(vp, FWRITE, cred, p); 1596 if (error == 0) 1597 error = (*pr->ps_emul->e_coredump)(p, &io); 1598 vrele(vp); 1599 out: 1600 crfree(cred); 1601 return (error); 1602 #endif 1603 } 1604 1605 #ifndef SMALL_KERNEL 1606 int 1607 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1608 { 1609 struct coredump_iostate *io = cookie; 1610 off_t coffset = 0; 1611 size_t csize; 1612 int chunk, error; 1613 1614 csize = len; 1615 do { 1616 if (io->io_proc->p_siglist & sigmask(SIGKILL)) 1617 return (EINTR); 1618 1619 /* Rest of the loop sleeps with lock held, so... */ 1620 yield(); 1621 1622 chunk = MIN(csize, MAXPHYS); 1623 error = vn_rdwr(UIO_WRITE, io->io_vp, 1624 (caddr_t)data + coffset, chunk, 1625 io->io_offset + coffset, segflg, 1626 IO_UNIT, io->io_cred, NULL, io->io_proc); 1627 if (error) { 1628 struct process *pr = io->io_proc->p_p; 1629 if (error == ENOSPC) 1630 log(LOG_ERR, "coredump of %s(%d) failed, filesystem full\n", 1631 pr->ps_comm, pr->ps_pid); 1632 else 1633 log(LOG_ERR, "coredump of %s(%d), write failed: errno %d\n", 1634 pr->ps_comm, pr->ps_pid, error); 1635 return (error); 1636 } 1637 1638 coffset += chunk; 1639 csize -= chunk; 1640 } while (csize > 0); 1641 1642 io->io_offset += len; 1643 return (0); 1644 } 1645 1646 void 1647 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1648 { 1649 struct coredump_iostate *io = cookie; 1650 1651 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1652 } 1653 1654 #endif /* !SMALL_KERNEL */ 1655 1656 /* 1657 * Nonexistent system call-- signal process (may want to handle it). 1658 * Flag error in case process won't see signal immediately (blocked or ignored). 1659 */ 1660 int 1661 sys_nosys(struct proc *p, void *v, register_t *retval) 1662 { 1663 1664 ptsignal(p, SIGSYS, STHREAD); 1665 return (ENOSYS); 1666 } 1667 1668 int 1669 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1670 { 1671 static int sigwaitsleep; 1672 struct sys___thrsigdivert_args /* { 1673 syscallarg(sigset_t) sigmask; 1674 syscallarg(siginfo_t *) info; 1675 syscallarg(const struct timespec *) timeout; 1676 } */ *uap = v; 1677 struct process *pr = p->p_p; 1678 sigset_t *m; 1679 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1680 siginfo_t si; 1681 uint64_t to_ticks = 0; 1682 int timeinvalid = 0; 1683 int error = 0; 1684 1685 memset(&si, 0, sizeof(si)); 1686 1687 if (SCARG(uap, timeout) != NULL) { 1688 struct timespec ts; 1689 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1690 return (error); 1691 #ifdef KTRACE 1692 if (KTRPOINT(p, KTR_STRUCT)) 1693 ktrreltimespec(p, &ts); 1694 #endif 1695 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) 1696 timeinvalid = 1; 1697 else { 1698 to_ticks = (uint64_t)hz * ts.tv_sec + 1699 ts.tv_nsec / (tick * 1000); 1700 if (to_ticks > INT_MAX) 1701 to_ticks = INT_MAX; 1702 if (to_ticks == 0 && ts.tv_nsec) 1703 to_ticks = 1; 1704 } 1705 } 1706 1707 dosigsuspend(p, p->p_sigmask &~ mask); 1708 for (;;) { 1709 si.si_signo = CURSIG(p); 1710 if (si.si_signo != 0) { 1711 sigset_t smask = sigmask(si.si_signo); 1712 if (smask & mask) { 1713 if (p->p_siglist & smask) 1714 m = &p->p_siglist; 1715 else if (pr->ps_mainproc->p_siglist & smask) 1716 m = &pr->ps_mainproc->p_siglist; 1717 else { 1718 /* signal got eaten by someone else? */ 1719 continue; 1720 } 1721 atomic_clearbits_int(m, smask); 1722 error = 0; 1723 break; 1724 } 1725 } 1726 1727 /* per-POSIX, delay this error until after the above */ 1728 if (timeinvalid) 1729 error = EINVAL; 1730 1731 if (SCARG(uap, timeout) != NULL && to_ticks == 0) 1732 error = EAGAIN; 1733 1734 if (error != 0) 1735 break; 1736 1737 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1738 (int)to_ticks); 1739 } 1740 1741 if (error == 0) { 1742 *retval = si.si_signo; 1743 if (SCARG(uap, info) != NULL) 1744 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1745 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1746 /* 1747 * Restarting is wrong if there's a timeout, as it'll be 1748 * for the same interval again 1749 */ 1750 error = EINTR; 1751 } 1752 1753 return (error); 1754 } 1755 1756 void 1757 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1758 { 1759 memset(si, 0, sizeof(*si)); 1760 1761 si->si_signo = sig; 1762 si->si_code = code; 1763 if (code == SI_USER) { 1764 si->si_value = val; 1765 } else { 1766 switch (sig) { 1767 case SIGSEGV: 1768 case SIGILL: 1769 case SIGBUS: 1770 case SIGFPE: 1771 si->si_addr = val.sival_ptr; 1772 si->si_trapno = trapno; 1773 break; 1774 case SIGXFSZ: 1775 break; 1776 } 1777 } 1778 } 1779 1780 int 1781 filt_sigattach(struct knote *kn) 1782 { 1783 struct process *pr = curproc->p_p; 1784 1785 if (kn->kn_id >= NSIG) 1786 return EINVAL; 1787 1788 kn->kn_ptr.p_process = pr; 1789 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1790 1791 /* XXX lock the proc here while adding to the list? */ 1792 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1793 1794 return (0); 1795 } 1796 1797 void 1798 filt_sigdetach(struct knote *kn) 1799 { 1800 struct process *pr = kn->kn_ptr.p_process; 1801 1802 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1803 } 1804 1805 /* 1806 * signal knotes are shared with proc knotes, so we apply a mask to 1807 * the hint in order to differentiate them from process hints. This 1808 * could be avoided by using a signal-specific knote list, but probably 1809 * isn't worth the trouble. 1810 */ 1811 int 1812 filt_signal(struct knote *kn, long hint) 1813 { 1814 1815 if (hint & NOTE_SIGNAL) { 1816 hint &= ~NOTE_SIGNAL; 1817 1818 if (kn->kn_id == hint) 1819 kn->kn_data++; 1820 } 1821 return (kn->kn_data != 0); 1822 } 1823 1824 void 1825 userret(struct proc *p) 1826 { 1827 int signum; 1828 1829 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1830 if (p->p_flag & P_PROFPEND) { 1831 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1832 KERNEL_LOCK(); 1833 psignal(p, SIGPROF); 1834 KERNEL_UNLOCK(); 1835 } 1836 if (p->p_flag & P_ALRMPEND) { 1837 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1838 KERNEL_LOCK(); 1839 psignal(p, SIGVTALRM); 1840 KERNEL_UNLOCK(); 1841 } 1842 1843 if (SIGPENDING(p)) { 1844 KERNEL_LOCK(); 1845 while ((signum = CURSIG(p)) != 0) 1846 postsig(p, signum); 1847 KERNEL_UNLOCK(); 1848 } 1849 1850 /* 1851 * If P_SIGSUSPEND is still set here, then we still need to restore 1852 * the original sigmask before returning to userspace. Also, this 1853 * might unmask some pending signals, so we need to check a second 1854 * time for signals to post. 1855 */ 1856 if (p->p_flag & P_SIGSUSPEND) { 1857 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1858 p->p_sigmask = p->p_oldmask; 1859 1860 KERNEL_LOCK(); 1861 while ((signum = CURSIG(p)) != 0) 1862 postsig(p, signum); 1863 KERNEL_UNLOCK(); 1864 } 1865 1866 if (p->p_flag & P_SUSPSINGLE) { 1867 KERNEL_LOCK(); 1868 single_thread_check(p, 0); 1869 KERNEL_UNLOCK(); 1870 } 1871 1872 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1873 1874 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1875 } 1876 1877 int 1878 single_thread_check(struct proc *p, int deep) 1879 { 1880 struct process *pr = p->p_p; 1881 1882 if (pr->ps_single != NULL && pr->ps_single != p) { 1883 do { 1884 int s; 1885 1886 /* if we're in deep, we need to unwind to the edge */ 1887 if (deep) { 1888 if (pr->ps_flags & PS_SINGLEUNWIND) 1889 return (ERESTART); 1890 if (pr->ps_flags & PS_SINGLEEXIT) 1891 return (EINTR); 1892 } 1893 1894 if (--pr->ps_singlecount == 0) 1895 wakeup(&pr->ps_singlecount); 1896 if (pr->ps_flags & PS_SINGLEEXIT) 1897 exit1(p, 0, EXIT_THREAD_NOCHECK); 1898 1899 /* not exiting and don't need to unwind, so suspend */ 1900 SCHED_LOCK(s); 1901 p->p_stat = SSTOP; 1902 mi_switch(); 1903 SCHED_UNLOCK(s); 1904 } while (pr->ps_single != NULL); 1905 } 1906 1907 return (0); 1908 } 1909 1910 /* 1911 * Stop other threads in the process. The mode controls how and 1912 * where the other threads should stop: 1913 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1914 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1915 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1916 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1917 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1918 * or released as with SINGLE_SUSPEND 1919 * - SINGLE_EXIT: unwind to kernel boundary and exit 1920 */ 1921 int 1922 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1923 { 1924 struct process *pr = p->p_p; 1925 struct proc *q; 1926 int error; 1927 1928 KERNEL_ASSERT_LOCKED(); 1929 1930 if ((error = single_thread_check(p, deep))) 1931 return error; 1932 1933 switch (mode) { 1934 case SINGLE_SUSPEND: 1935 case SINGLE_PTRACE: 1936 break; 1937 case SINGLE_UNWIND: 1938 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1939 break; 1940 case SINGLE_EXIT: 1941 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1942 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1943 break; 1944 #ifdef DIAGNOSTIC 1945 default: 1946 panic("single_thread_mode = %d", mode); 1947 #endif 1948 } 1949 pr->ps_single = p; 1950 pr->ps_singlecount = 0; 1951 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1952 int s; 1953 1954 if (q == p) 1955 continue; 1956 if (q->p_flag & P_WEXIT) { 1957 if (mode == SINGLE_EXIT) { 1958 SCHED_LOCK(s); 1959 if (q->p_stat == SSTOP) { 1960 setrunnable(q); 1961 pr->ps_singlecount++; 1962 } 1963 SCHED_UNLOCK(s); 1964 } 1965 continue; 1966 } 1967 SCHED_LOCK(s); 1968 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 1969 switch (q->p_stat) { 1970 case SIDL: 1971 case SRUN: 1972 pr->ps_singlecount++; 1973 break; 1974 case SSLEEP: 1975 /* if it's not interruptible, then just have to wait */ 1976 if (q->p_flag & P_SINTR) { 1977 /* merely need to suspend? just stop it */ 1978 if (mode == SINGLE_SUSPEND || 1979 mode == SINGLE_PTRACE) { 1980 q->p_stat = SSTOP; 1981 break; 1982 } 1983 /* need to unwind or exit, so wake it */ 1984 setrunnable(q); 1985 } 1986 pr->ps_singlecount++; 1987 break; 1988 case SSTOP: 1989 if (mode == SINGLE_EXIT) { 1990 setrunnable(q); 1991 pr->ps_singlecount++; 1992 } 1993 break; 1994 case SDEAD: 1995 break; 1996 case SONPROC: 1997 pr->ps_singlecount++; 1998 signotify(q); 1999 break; 2000 } 2001 SCHED_UNLOCK(s); 2002 } 2003 2004 if (mode != SINGLE_PTRACE) 2005 single_thread_wait(pr); 2006 2007 return 0; 2008 } 2009 2010 void 2011 single_thread_wait(struct process *pr) 2012 { 2013 /* wait until they're all suspended */ 2014 while (pr->ps_singlecount > 0) 2015 tsleep(&pr->ps_singlecount, PUSER, "suspend", 0); 2016 } 2017 2018 void 2019 single_thread_clear(struct proc *p, int flag) 2020 { 2021 struct process *pr = p->p_p; 2022 struct proc *q; 2023 2024 KASSERT(pr->ps_single == p); 2025 KERNEL_ASSERT_LOCKED(); 2026 2027 pr->ps_single = NULL; 2028 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2029 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2030 int s; 2031 2032 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2033 continue; 2034 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2035 2036 /* 2037 * if the thread was only stopped for single threading 2038 * then clearing that either makes it runnable or puts 2039 * it back into some sleep queue 2040 */ 2041 SCHED_LOCK(s); 2042 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2043 if (q->p_wchan == 0) 2044 setrunnable(q); 2045 else 2046 q->p_stat = SSLEEP; 2047 } 2048 SCHED_UNLOCK(s); 2049 } 2050 } 2051