1 /* $OpenBSD: kern_sig.c,v 1.234 2019/10/03 13:58:59 deraadt 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 void sigio_del(struct sigiolst *); 91 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 92 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 93 94 /* 95 * Can thread p, send the signal signum to process qr? 96 */ 97 int 98 cansignal(struct proc *p, struct process *qr, int signum) 99 { 100 struct process *pr = p->p_p; 101 struct ucred *uc = p->p_ucred; 102 struct ucred *quc = qr->ps_ucred; 103 104 if (uc->cr_uid == 0) 105 return (1); /* root can always signal */ 106 107 if (pr == qr) 108 return (1); /* process can always signal itself */ 109 110 /* optimization: if the same creds then the tests below will pass */ 111 if (uc == quc) 112 return (1); 113 114 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 115 return (1); /* SIGCONT in session */ 116 117 /* 118 * Using kill(), only certain signals can be sent to setugid 119 * child processes 120 */ 121 if (qr->ps_flags & PS_SUGID) { 122 switch (signum) { 123 case 0: 124 case SIGKILL: 125 case SIGINT: 126 case SIGTERM: 127 case SIGALRM: 128 case SIGSTOP: 129 case SIGTTIN: 130 case SIGTTOU: 131 case SIGTSTP: 132 case SIGHUP: 133 case SIGUSR1: 134 case SIGUSR2: 135 if (uc->cr_ruid == quc->cr_ruid || 136 uc->cr_uid == quc->cr_ruid) 137 return (1); 138 } 139 return (0); 140 } 141 142 if (uc->cr_ruid == quc->cr_ruid || 143 uc->cr_ruid == quc->cr_svuid || 144 uc->cr_uid == quc->cr_ruid || 145 uc->cr_uid == quc->cr_svuid) 146 return (1); 147 return (0); 148 } 149 150 /* 151 * Initialize signal-related data structures. 152 */ 153 void 154 signal_init(void) 155 { 156 timeout_set(&proc_stop_to, proc_stop_sweep, NULL); 157 158 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 159 PR_WAITOK, "sigapl", NULL); 160 } 161 162 /* 163 * Create an initial sigacts structure, using the same signal state 164 * as p. 165 */ 166 struct sigacts * 167 sigactsinit(struct process *pr) 168 { 169 struct sigacts *ps; 170 171 ps = pool_get(&sigacts_pool, PR_WAITOK); 172 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 173 ps->ps_refcnt = 1; 174 return (ps); 175 } 176 177 /* 178 * Share a sigacts structure. 179 */ 180 struct sigacts * 181 sigactsshare(struct process *pr) 182 { 183 struct sigacts *ps = pr->ps_sigacts; 184 185 ps->ps_refcnt++; 186 return ps; 187 } 188 189 /* 190 * Initialize a new sigaltstack structure. 191 */ 192 void 193 sigstkinit(struct sigaltstack *ss) 194 { 195 ss->ss_flags = SS_DISABLE; 196 ss->ss_size = 0; 197 ss->ss_sp = 0; 198 } 199 200 /* 201 * Make this process not share its sigacts, maintaining all 202 * signal state. 203 */ 204 void 205 sigactsunshare(struct process *pr) 206 { 207 struct sigacts *newps; 208 209 if (pr->ps_sigacts->ps_refcnt == 1) 210 return; 211 212 newps = sigactsinit(pr); 213 sigactsfree(pr); 214 pr->ps_sigacts = newps; 215 } 216 217 /* 218 * Release a sigacts structure. 219 */ 220 void 221 sigactsfree(struct process *pr) 222 { 223 struct sigacts *ps = pr->ps_sigacts; 224 225 if (--ps->ps_refcnt > 0) 226 return; 227 228 pr->ps_sigacts = NULL; 229 230 pool_put(&sigacts_pool, ps); 231 } 232 233 int 234 sys_sigaction(struct proc *p, void *v, register_t *retval) 235 { 236 struct sys_sigaction_args /* { 237 syscallarg(int) signum; 238 syscallarg(const struct sigaction *) nsa; 239 syscallarg(struct sigaction *) osa; 240 } */ *uap = v; 241 struct sigaction vec; 242 #ifdef KTRACE 243 struct sigaction ovec; 244 #endif 245 struct sigaction *sa; 246 const struct sigaction *nsa; 247 struct sigaction *osa; 248 struct sigacts *ps = p->p_p->ps_sigacts; 249 int signum; 250 int bit, error; 251 252 signum = SCARG(uap, signum); 253 nsa = SCARG(uap, nsa); 254 osa = SCARG(uap, osa); 255 256 if (signum <= 0 || signum >= NSIG || 257 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 258 return (EINVAL); 259 sa = &vec; 260 if (osa) { 261 sa->sa_handler = ps->ps_sigact[signum]; 262 sa->sa_mask = ps->ps_catchmask[signum]; 263 bit = sigmask(signum); 264 sa->sa_flags = 0; 265 if ((ps->ps_sigonstack & bit) != 0) 266 sa->sa_flags |= SA_ONSTACK; 267 if ((ps->ps_sigintr & bit) == 0) 268 sa->sa_flags |= SA_RESTART; 269 if ((ps->ps_sigreset & bit) != 0) 270 sa->sa_flags |= SA_RESETHAND; 271 if ((ps->ps_siginfo & bit) != 0) 272 sa->sa_flags |= SA_SIGINFO; 273 if (signum == SIGCHLD) { 274 if ((ps->ps_flags & SAS_NOCLDSTOP) != 0) 275 sa->sa_flags |= SA_NOCLDSTOP; 276 if ((ps->ps_flags & SAS_NOCLDWAIT) != 0) 277 sa->sa_flags |= SA_NOCLDWAIT; 278 } 279 if ((sa->sa_mask & bit) == 0) 280 sa->sa_flags |= SA_NODEFER; 281 sa->sa_mask &= ~bit; 282 error = copyout(sa, osa, sizeof (vec)); 283 if (error) 284 return (error); 285 #ifdef KTRACE 286 if (KTRPOINT(p, KTR_STRUCT)) 287 ovec = vec; 288 #endif 289 } 290 if (nsa) { 291 error = copyin(nsa, sa, sizeof (vec)); 292 if (error) 293 return (error); 294 #ifdef KTRACE 295 if (KTRPOINT(p, KTR_STRUCT)) 296 ktrsigaction(p, sa); 297 #endif 298 setsigvec(p, signum, sa); 299 } 300 #ifdef KTRACE 301 if (osa && KTRPOINT(p, KTR_STRUCT)) 302 ktrsigaction(p, &ovec); 303 #endif 304 return (0); 305 } 306 307 void 308 setsigvec(struct proc *p, int signum, struct sigaction *sa) 309 { 310 struct sigacts *ps = p->p_p->ps_sigacts; 311 int bit; 312 int s; 313 314 bit = sigmask(signum); 315 /* 316 * Change setting atomically. 317 */ 318 s = splhigh(); 319 ps->ps_sigact[signum] = sa->sa_handler; 320 if ((sa->sa_flags & SA_NODEFER) == 0) 321 sa->sa_mask |= sigmask(signum); 322 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 323 if (signum == SIGCHLD) { 324 if (sa->sa_flags & SA_NOCLDSTOP) 325 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 326 else 327 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDSTOP); 328 /* 329 * If the SA_NOCLDWAIT flag is set or the handler 330 * is SIG_IGN we reparent the dying child to PID 1 331 * (init) which will reap the zombie. Because we use 332 * init to do our dirty work we never set SAS_NOCLDWAIT 333 * for PID 1. 334 * XXX exit1 rework means this is unnecessary? 335 */ 336 if (initprocess->ps_sigacts != ps && 337 ((sa->sa_flags & SA_NOCLDWAIT) || 338 sa->sa_handler == SIG_IGN)) 339 atomic_setbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 340 else 341 atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT); 342 } 343 if ((sa->sa_flags & SA_RESETHAND) != 0) 344 ps->ps_sigreset |= bit; 345 else 346 ps->ps_sigreset &= ~bit; 347 if ((sa->sa_flags & SA_SIGINFO) != 0) 348 ps->ps_siginfo |= bit; 349 else 350 ps->ps_siginfo &= ~bit; 351 if ((sa->sa_flags & SA_RESTART) == 0) 352 ps->ps_sigintr |= bit; 353 else 354 ps->ps_sigintr &= ~bit; 355 if ((sa->sa_flags & SA_ONSTACK) != 0) 356 ps->ps_sigonstack |= bit; 357 else 358 ps->ps_sigonstack &= ~bit; 359 /* 360 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 361 * and for signals set to SIG_DFL where the default is to ignore. 362 * However, don't put SIGCONT in ps_sigignore, 363 * as we have to restart the process. 364 */ 365 if (sa->sa_handler == SIG_IGN || 366 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 367 atomic_clearbits_int(&p->p_siglist, bit); 368 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 369 if (signum != SIGCONT) 370 ps->ps_sigignore |= bit; /* easier in psignal */ 371 ps->ps_sigcatch &= ~bit; 372 } else { 373 ps->ps_sigignore &= ~bit; 374 if (sa->sa_handler == SIG_DFL) 375 ps->ps_sigcatch &= ~bit; 376 else 377 ps->ps_sigcatch |= bit; 378 } 379 splx(s); 380 } 381 382 /* 383 * Initialize signal state for process 0; 384 * set to ignore signals that are ignored by default. 385 */ 386 void 387 siginit(struct process *pr) 388 { 389 struct sigacts *ps = pr->ps_sigacts; 390 int i; 391 392 for (i = 0; i < NSIG; i++) 393 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 394 ps->ps_sigignore |= sigmask(i); 395 ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 396 } 397 398 /* 399 * Reset signals for an exec by the specified thread. 400 */ 401 void 402 execsigs(struct proc *p) 403 { 404 struct sigacts *ps; 405 int nc, mask; 406 407 sigactsunshare(p->p_p); 408 ps = p->p_p->ps_sigacts; 409 410 /* 411 * Reset caught signals. Held signals remain held 412 * through p_sigmask (unless they were caught, 413 * and are now ignored by default). 414 */ 415 while (ps->ps_sigcatch) { 416 nc = ffs((long)ps->ps_sigcatch); 417 mask = sigmask(nc); 418 ps->ps_sigcatch &= ~mask; 419 if (sigprop[nc] & SA_IGNORE) { 420 if (nc != SIGCONT) 421 ps->ps_sigignore |= mask; 422 atomic_clearbits_int(&p->p_siglist, mask); 423 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 424 } 425 ps->ps_sigact[nc] = SIG_DFL; 426 } 427 /* 428 * Reset stack state to the user stack. 429 * Clear set of signals caught on the signal stack. 430 */ 431 sigstkinit(&p->p_sigstk); 432 ps->ps_flags &= ~SAS_NOCLDWAIT; 433 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 434 ps->ps_sigact[SIGCHLD] = SIG_DFL; 435 } 436 437 /* 438 * Manipulate signal mask. 439 * Note that we receive new mask, not pointer, 440 * and return old mask as return value; 441 * the library stub does the rest. 442 */ 443 int 444 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 445 { 446 struct sys_sigprocmask_args /* { 447 syscallarg(int) how; 448 syscallarg(sigset_t) mask; 449 } */ *uap = v; 450 int error = 0; 451 sigset_t mask; 452 453 *retval = p->p_sigmask; 454 mask = SCARG(uap, mask) &~ sigcantmask; 455 456 switch (SCARG(uap, how)) { 457 case SIG_BLOCK: 458 atomic_setbits_int(&p->p_sigmask, mask); 459 break; 460 case SIG_UNBLOCK: 461 atomic_clearbits_int(&p->p_sigmask, mask); 462 break; 463 case SIG_SETMASK: 464 p->p_sigmask = mask; 465 break; 466 default: 467 error = EINVAL; 468 break; 469 } 470 return (error); 471 } 472 473 int 474 sys_sigpending(struct proc *p, void *v, register_t *retval) 475 { 476 477 *retval = p->p_siglist | p->p_p->ps_siglist; 478 return (0); 479 } 480 481 /* 482 * Temporarily replace calling proc's signal mask for the duration of a 483 * system call. Original signal mask will be restored by userret(). 484 */ 485 void 486 dosigsuspend(struct proc *p, sigset_t newmask) 487 { 488 KASSERT(p == curproc); 489 490 p->p_oldmask = p->p_sigmask; 491 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 492 p->p_sigmask = newmask; 493 } 494 495 /* 496 * Suspend process until signal, providing mask to be set 497 * in the meantime. Note nonstandard calling convention: 498 * libc stub passes mask, not pointer, to save a copyin. 499 */ 500 int 501 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 502 { 503 struct sys_sigsuspend_args /* { 504 syscallarg(int) mask; 505 } */ *uap = v; 506 struct process *pr = p->p_p; 507 struct sigacts *ps = pr->ps_sigacts; 508 509 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 510 while (tsleep(ps, PPAUSE|PCATCH, "pause", 0) == 0) 511 /* void */; 512 /* always return EINTR rather than ERESTART... */ 513 return (EINTR); 514 } 515 516 int 517 sigonstack(size_t stack) 518 { 519 const struct sigaltstack *ss = &curproc->p_sigstk; 520 521 return (ss->ss_flags & SS_DISABLE ? 0 : 522 (stack - (size_t)ss->ss_sp < ss->ss_size)); 523 } 524 525 int 526 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 527 { 528 struct sys_sigaltstack_args /* { 529 syscallarg(const struct sigaltstack *) nss; 530 syscallarg(struct sigaltstack *) oss; 531 } */ *uap = v; 532 struct sigaltstack ss; 533 const struct sigaltstack *nss; 534 struct sigaltstack *oss; 535 int onstack = sigonstack(PROC_STACK(p)); 536 int error; 537 538 nss = SCARG(uap, nss); 539 oss = SCARG(uap, oss); 540 541 if (oss != NULL) { 542 ss = p->p_sigstk; 543 if (onstack) 544 ss.ss_flags |= SS_ONSTACK; 545 if ((error = copyout(&ss, oss, sizeof(ss)))) 546 return (error); 547 } 548 if (nss == NULL) 549 return (0); 550 error = copyin(nss, &ss, sizeof(ss)); 551 if (error) 552 return (error); 553 if (onstack) 554 return (EPERM); 555 if (ss.ss_flags & ~SS_DISABLE) 556 return (EINVAL); 557 if (ss.ss_flags & SS_DISABLE) { 558 p->p_sigstk.ss_flags = ss.ss_flags; 559 return (0); 560 } 561 if (ss.ss_size < MINSIGSTKSZ) 562 return (ENOMEM); 563 564 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 565 if (error) 566 return (error); 567 568 p->p_sigstk = ss; 569 return (0); 570 } 571 572 int 573 sys_kill(struct proc *cp, void *v, register_t *retval) 574 { 575 struct sys_kill_args /* { 576 syscallarg(int) pid; 577 syscallarg(int) signum; 578 } */ *uap = v; 579 struct process *pr; 580 int pid = SCARG(uap, pid); 581 int signum = SCARG(uap, signum); 582 int error; 583 int zombie = 0; 584 585 if ((error = pledge_kill(cp, pid)) != 0) 586 return (error); 587 if (((u_int)signum) >= NSIG) 588 return (EINVAL); 589 if (pid > 0) { 590 if ((pr = prfind(pid)) == NULL) { 591 if ((pr = zombiefind(pid)) == NULL) 592 return (ESRCH); 593 else 594 zombie = 1; 595 } 596 if (!cansignal(cp, pr, signum)) 597 return (EPERM); 598 599 /* kill single process */ 600 if (signum && !zombie) 601 prsignal(pr, signum); 602 return (0); 603 } 604 switch (pid) { 605 case -1: /* broadcast signal */ 606 return (killpg1(cp, signum, 0, 1)); 607 case 0: /* signal own process group */ 608 return (killpg1(cp, signum, 0, 0)); 609 default: /* negative explicit process group */ 610 return (killpg1(cp, signum, -pid, 0)); 611 } 612 } 613 614 int 615 sys_thrkill(struct proc *cp, void *v, register_t *retval) 616 { 617 struct sys_thrkill_args /* { 618 syscallarg(pid_t) tid; 619 syscallarg(int) signum; 620 syscallarg(void *) tcb; 621 } */ *uap = v; 622 struct proc *p; 623 int tid = SCARG(uap, tid); 624 int signum = SCARG(uap, signum); 625 void *tcb; 626 627 if (((u_int)signum) >= NSIG) 628 return (EINVAL); 629 if (tid > THREAD_PID_OFFSET) { 630 if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL) 631 return (ESRCH); 632 633 /* can only kill threads in the same process */ 634 if (p->p_p != cp->p_p) 635 return (ESRCH); 636 } else if (tid == 0) 637 p = cp; 638 else 639 return (EINVAL); 640 641 /* optionally require the target thread to have the given tcb addr */ 642 tcb = SCARG(uap, tcb); 643 if (tcb != NULL && tcb != TCB_GET(p)) 644 return (ESRCH); 645 646 if (signum) 647 ptsignal(p, signum, STHREAD); 648 return (0); 649 } 650 651 /* 652 * Common code for kill process group/broadcast kill. 653 * cp is calling process. 654 */ 655 int 656 killpg1(struct proc *cp, int signum, int pgid, int all) 657 { 658 struct process *pr; 659 struct pgrp *pgrp; 660 int nfound = 0; 661 662 if (all) { 663 /* 664 * broadcast 665 */ 666 LIST_FOREACH(pr, &allprocess, ps_list) { 667 if (pr->ps_pid <= 1 || 668 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 669 pr == cp->p_p || !cansignal(cp, pr, signum)) 670 continue; 671 nfound++; 672 if (signum) 673 prsignal(pr, signum); 674 } 675 } else { 676 if (pgid == 0) 677 /* 678 * zero pgid means send to my process group. 679 */ 680 pgrp = cp->p_p->ps_pgrp; 681 else { 682 pgrp = pgfind(pgid); 683 if (pgrp == NULL) 684 return (ESRCH); 685 } 686 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 687 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 688 !cansignal(cp, pr, signum)) 689 continue; 690 nfound++; 691 if (signum) 692 prsignal(pr, signum); 693 } 694 } 695 return (nfound ? 0 : ESRCH); 696 } 697 698 #define CANDELIVER(uid, euid, pr) \ 699 (euid == 0 || \ 700 (uid) == (pr)->ps_ucred->cr_ruid || \ 701 (uid) == (pr)->ps_ucred->cr_svuid || \ 702 (uid) == (pr)->ps_ucred->cr_uid || \ 703 (euid) == (pr)->ps_ucred->cr_ruid || \ 704 (euid) == (pr)->ps_ucred->cr_svuid || \ 705 (euid) == (pr)->ps_ucred->cr_uid) 706 707 #define CANSIGIO(cr, pr) \ 708 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 709 710 /* 711 * Deliver signum to pgid, but first check uid/euid against each 712 * process and see if it is permitted. 713 */ 714 void 715 csignal(pid_t pgid, int signum, uid_t uid, uid_t euid) 716 { 717 struct pgrp *pgrp; 718 struct process *pr; 719 720 if (pgid == 0) 721 return; 722 if (pgid < 0) { 723 pgid = -pgid; 724 if ((pgrp = pgfind(pgid)) == NULL) 725 return; 726 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 727 if (CANDELIVER(uid, euid, pr)) 728 prsignal(pr, signum); 729 } else { 730 if ((pr = prfind(pgid)) == NULL) 731 return; 732 if (CANDELIVER(uid, euid, pr)) 733 prsignal(pr, signum); 734 } 735 } 736 737 /* 738 * Send a signal to a process group. If checktty is 1, 739 * limit to members which have a controlling terminal. 740 */ 741 void 742 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 743 { 744 struct process *pr; 745 746 if (pgrp) 747 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 748 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 749 prsignal(pr, signum); 750 } 751 752 /* 753 * Send a SIGIO or SIGURG signal to a process or process group using stored 754 * credentials rather than those of the current process. 755 */ 756 void 757 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 758 { 759 struct process *pr; 760 struct sigio *sigio; 761 762 if (sir->sir_sigio == NULL) 763 return; 764 765 mtx_enter(&sigio_lock); 766 sigio = sir->sir_sigio; 767 if (sigio == NULL) 768 goto out; 769 if (sigio->sio_pgid > 0) { 770 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 771 prsignal(sigio->sio_proc, sig); 772 } else if (sigio->sio_pgid < 0) { 773 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 774 if (CANSIGIO(sigio->sio_ucred, pr) && 775 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 776 prsignal(pr, sig); 777 } 778 } 779 out: 780 mtx_leave(&sigio_lock); 781 } 782 783 /* 784 * Recalculate the signal mask and reset the signal disposition after 785 * usermode frame for delivery is formed. 786 */ 787 void 788 postsig_done(struct proc *p, int signum, struct sigacts *ps) 789 { 790 int mask = sigmask(signum); 791 792 KERNEL_ASSERT_LOCKED(); 793 794 p->p_ru.ru_nsignals++; 795 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 796 if ((ps->ps_sigreset & mask) != 0) { 797 ps->ps_sigcatch &= ~mask; 798 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 799 ps->ps_sigignore |= mask; 800 ps->ps_sigact[signum] = SIG_DFL; 801 } 802 } 803 804 /* 805 * Send a signal caused by a trap to the current thread 806 * If it will be caught immediately, deliver it with correct code. 807 * Otherwise, post it normally. 808 */ 809 void 810 trapsignal(struct proc *p, int signum, u_long trapno, int code, 811 union sigval sigval) 812 { 813 struct process *pr = p->p_p; 814 struct sigacts *ps = pr->ps_sigacts; 815 int mask; 816 817 switch (signum) { 818 case SIGILL: 819 case SIGBUS: 820 case SIGSEGV: 821 pr->ps_acflag |= ATRAP; 822 break; 823 } 824 825 mask = sigmask(signum); 826 if ((pr->ps_flags & PS_TRACED) == 0 && 827 (ps->ps_sigcatch & mask) != 0 && 828 (p->p_sigmask & mask) == 0) { 829 siginfo_t si; 830 initsiginfo(&si, signum, trapno, code, sigval); 831 #ifdef KTRACE 832 if (KTRPOINT(p, KTR_PSIG)) { 833 ktrpsig(p, signum, ps->ps_sigact[signum], 834 p->p_sigmask, code, &si); 835 } 836 #endif 837 sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si); 838 postsig_done(p, signum, ps); 839 } else { 840 p->p_sisig = signum; 841 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 842 p->p_sicode = code; 843 p->p_sigval = sigval; 844 845 /* 846 * Signals like SIGBUS and SIGSEGV should not, when 847 * generated by the kernel, be ignorable or blockable. 848 * If it is and we're not being traced, then just kill 849 * the process. 850 */ 851 if ((pr->ps_flags & PS_TRACED) == 0 && 852 (sigprop[signum] & SA_KILL) && 853 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 854 sigexit(p, signum); 855 ptsignal(p, signum, STHREAD); 856 } 857 } 858 859 /* 860 * Send the signal to the process. If the signal has an action, the action 861 * is usually performed by the target process rather than the caller; we add 862 * the signal to the set of pending signals for the process. 863 * 864 * Exceptions: 865 * o When a stop signal is sent to a sleeping process that takes the 866 * default action, the process is stopped without awakening it. 867 * o SIGCONT restarts stopped processes (or puts them back to sleep) 868 * regardless of the signal action (eg, blocked or ignored). 869 * 870 * Other ignored signals are discarded immediately. 871 */ 872 void 873 psignal(struct proc *p, int signum) 874 { 875 ptsignal(p, signum, SPROCESS); 876 } 877 878 /* 879 * type = SPROCESS process signal, can be diverted (sigwait()) 880 * type = STHREAD thread signal, but should be propagated if unhandled 881 * type = SPROPAGATED propagated to this thread, so don't propagate again 882 */ 883 void 884 ptsignal(struct proc *p, int signum, enum signal_type type) 885 { 886 int s, prop; 887 sig_t action; 888 int mask; 889 int *siglist; 890 struct process *pr = p->p_p; 891 struct proc *q; 892 int wakeparent = 0; 893 894 KERNEL_ASSERT_LOCKED(); 895 896 #ifdef DIAGNOSTIC 897 if ((u_int)signum >= NSIG || signum == 0) 898 panic("psignal signal number"); 899 #endif 900 901 /* Ignore signal if the target process is exiting */ 902 if (pr->ps_flags & PS_EXITING) 903 return; 904 905 mask = sigmask(signum); 906 907 if (type == SPROCESS) { 908 /* Accept SIGKILL to coredumping processes */ 909 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 910 if (pr->ps_single != NULL) 911 p = pr->ps_single; 912 atomic_setbits_int(&p->p_p->ps_siglist, mask); 913 return; 914 } 915 916 /* 917 * If the current thread can process the signal 918 * immediately (it's unblocked) then have it take it. 919 */ 920 q = curproc; 921 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 922 (q->p_sigmask & mask) == 0) 923 p = q; 924 else { 925 /* 926 * A process-wide signal can be diverted to a 927 * different thread that's in sigwait() for this 928 * signal. If there isn't such a thread, then 929 * pick a thread that doesn't have it blocked so 930 * that the stop/kill consideration isn't 931 * delayed. Otherwise, mark it pending on the 932 * main thread. 933 */ 934 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 935 /* ignore exiting threads */ 936 if (q->p_flag & P_WEXIT) 937 continue; 938 939 /* skip threads that have the signal blocked */ 940 if ((q->p_sigmask & mask) != 0) 941 continue; 942 943 /* okay, could send to this thread */ 944 p = q; 945 946 /* 947 * sigsuspend, sigwait, ppoll/pselect, etc? 948 * Definitely go to this thread, as it's 949 * already blocked in the kernel. 950 */ 951 if (q->p_flag & P_SIGSUSPEND) 952 break; 953 } 954 } 955 } 956 957 if (type != SPROPAGATED) 958 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 959 960 prop = sigprop[signum]; 961 962 /* 963 * If proc is traced, always give parent a chance. 964 */ 965 if (pr->ps_flags & PS_TRACED) { 966 action = SIG_DFL; 967 } else { 968 /* 969 * If the signal is being ignored, 970 * then we forget about it immediately. 971 * (Note: we don't set SIGCONT in ps_sigignore, 972 * and if it is set to SIG_IGN, 973 * action will be SIG_DFL here.) 974 */ 975 if (pr->ps_sigacts->ps_sigignore & mask) 976 return; 977 if (p->p_sigmask & mask) { 978 action = SIG_HOLD; 979 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 980 action = SIG_CATCH; 981 } else { 982 action = SIG_DFL; 983 984 if (prop & SA_KILL && pr->ps_nice > NZERO) 985 pr->ps_nice = NZERO; 986 987 /* 988 * If sending a tty stop signal to a member of an 989 * orphaned process group, discard the signal here if 990 * the action is default; don't stop the process below 991 * if sleeping, and don't clear any pending SIGCONT. 992 */ 993 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 994 return; 995 } 996 } 997 /* 998 * If delivered to process, mark as pending there. Continue and stop 999 * signals will be propagated to all threads. So they are always 1000 * marked at thread level. 1001 */ 1002 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1003 if (prop & SA_CONT) { 1004 siglist = &p->p_siglist; 1005 atomic_clearbits_int(siglist, stopsigmask); 1006 } 1007 if (prop & SA_STOP) { 1008 siglist = &p->p_siglist; 1009 atomic_clearbits_int(siglist, contsigmask); 1010 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1011 } 1012 atomic_setbits_int(siglist, mask); 1013 1014 /* 1015 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1016 */ 1017 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1018 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1019 if (q != p) 1020 ptsignal(q, signum, SPROPAGATED); 1021 1022 /* 1023 * Defer further processing for signals which are held, 1024 * except that stopped processes must be continued by SIGCONT. 1025 */ 1026 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 1027 return; 1028 1029 SCHED_LOCK(s); 1030 1031 switch (p->p_stat) { 1032 1033 case SSLEEP: 1034 /* 1035 * If process is sleeping uninterruptibly 1036 * we can't interrupt the sleep... the signal will 1037 * be noticed when the process returns through 1038 * trap() or syscall(). 1039 */ 1040 if ((p->p_flag & P_SINTR) == 0) 1041 goto out; 1042 /* 1043 * Process is sleeping and traced... make it runnable 1044 * so it can discover the signal in issignal() and stop 1045 * for the parent. 1046 */ 1047 if (pr->ps_flags & PS_TRACED) 1048 goto run; 1049 /* 1050 * If SIGCONT is default (or ignored) and process is 1051 * asleep, we are finished; the process should not 1052 * be awakened. 1053 */ 1054 if ((prop & SA_CONT) && action == SIG_DFL) { 1055 atomic_clearbits_int(siglist, mask); 1056 goto out; 1057 } 1058 /* 1059 * When a sleeping process receives a stop 1060 * signal, process immediately if possible. 1061 */ 1062 if ((prop & SA_STOP) && action == SIG_DFL) { 1063 /* 1064 * If a child holding parent blocked, 1065 * stopping could cause deadlock. 1066 */ 1067 if (pr->ps_flags & PS_PPWAIT) 1068 goto out; 1069 atomic_clearbits_int(siglist, mask); 1070 p->p_xstat = signum; 1071 proc_stop(p, 0); 1072 goto out; 1073 } 1074 /* 1075 * All other (caught or default) signals 1076 * cause the process to run. 1077 */ 1078 goto runfast; 1079 /*NOTREACHED*/ 1080 1081 case SSTOP: 1082 /* 1083 * If traced process is already stopped, 1084 * then no further action is necessary. 1085 */ 1086 if (pr->ps_flags & PS_TRACED) 1087 goto out; 1088 1089 /* 1090 * Kill signal always sets processes running. 1091 */ 1092 if (signum == SIGKILL) { 1093 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1094 goto runfast; 1095 } 1096 1097 if (prop & SA_CONT) { 1098 /* 1099 * If SIGCONT is default (or ignored), we continue the 1100 * process but don't leave the signal in p_siglist, as 1101 * it has no further action. If SIGCONT is held, we 1102 * continue the process and leave the signal in 1103 * p_siglist. If the process catches SIGCONT, let it 1104 * handle the signal itself. If it isn't waiting on 1105 * an event, then it goes back to run state. 1106 * Otherwise, process goes back to sleep state. 1107 */ 1108 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1109 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1110 wakeparent = 1; 1111 if (action == SIG_DFL) 1112 atomic_clearbits_int(siglist, mask); 1113 if (action == SIG_CATCH) 1114 goto runfast; 1115 if (p->p_wchan == 0) 1116 goto run; 1117 p->p_stat = SSLEEP; 1118 goto out; 1119 } 1120 1121 if (prop & SA_STOP) { 1122 /* 1123 * Already stopped, don't need to stop again. 1124 * (If we did the shell could get confused.) 1125 */ 1126 atomic_clearbits_int(siglist, mask); 1127 goto out; 1128 } 1129 1130 /* 1131 * If process is sleeping interruptibly, then simulate a 1132 * wakeup so that when it is continued, it will be made 1133 * runnable and can look at the signal. But don't make 1134 * the process runnable, leave it stopped. 1135 */ 1136 if (p->p_wchan && p->p_flag & P_SINTR) 1137 unsleep(p); 1138 goto out; 1139 1140 case SONPROC: 1141 signotify(p); 1142 /* FALLTHROUGH */ 1143 default: 1144 /* 1145 * SRUN, SIDL, SDEAD do nothing with the signal, 1146 * other than kicking ourselves if we are running. 1147 * It will either never be noticed, or noticed very soon. 1148 */ 1149 goto out; 1150 } 1151 /*NOTREACHED*/ 1152 1153 runfast: 1154 /* 1155 * Raise priority to at least PUSER. 1156 */ 1157 if (p->p_priority > PUSER) 1158 p->p_priority = PUSER; 1159 run: 1160 setrunnable(p); 1161 out: 1162 SCHED_UNLOCK(s); 1163 if (wakeparent) 1164 wakeup(pr->ps_pptr); 1165 } 1166 1167 /* 1168 * If the current process has received a signal (should be caught or cause 1169 * termination, should interrupt current syscall), return the signal number. 1170 * Stop signals with default action are processed immediately, then cleared; 1171 * they aren't returned. This is checked after each entry to the system for 1172 * a syscall or trap (though this can usually be done without calling issignal 1173 * by checking the pending signal masks in the CURSIG macro.) The normal call 1174 * sequence is 1175 * 1176 * while (signum = CURSIG(curproc)) 1177 * postsig(signum); 1178 * 1179 * Assumes that if the P_SINTR flag is set, we're holding both the 1180 * kernel and scheduler locks. 1181 */ 1182 int 1183 issignal(struct proc *p) 1184 { 1185 struct process *pr = p->p_p; 1186 int signum, mask, prop; 1187 int dolock = (p->p_flag & P_SINTR) == 0; 1188 int s; 1189 1190 for (;;) { 1191 mask = SIGPENDING(p); 1192 if (pr->ps_flags & PS_PPWAIT) 1193 mask &= ~stopsigmask; 1194 if (mask == 0) /* no signal to send */ 1195 return (0); 1196 signum = ffs((long)mask); 1197 mask = sigmask(signum); 1198 atomic_clearbits_int(&p->p_siglist, mask); 1199 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 1200 1201 /* 1202 * We should see pending but ignored signals 1203 * only if PS_TRACED was on when they were posted. 1204 */ 1205 if (mask & pr->ps_sigacts->ps_sigignore && 1206 (pr->ps_flags & PS_TRACED) == 0) 1207 continue; 1208 1209 /* 1210 * If traced, always stop, and stay stopped until released 1211 * by the debugger. If our parent process is waiting for 1212 * us, don't hang as we could deadlock. 1213 */ 1214 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1215 signum != SIGKILL) { 1216 p->p_xstat = signum; 1217 1218 if (dolock) 1219 KERNEL_LOCK(); 1220 single_thread_set(p, SINGLE_PTRACE, 0); 1221 if (dolock) 1222 KERNEL_UNLOCK(); 1223 1224 if (dolock) 1225 SCHED_LOCK(s); 1226 proc_stop(p, 1); 1227 if (dolock) 1228 SCHED_UNLOCK(s); 1229 1230 if (dolock) 1231 KERNEL_LOCK(); 1232 single_thread_clear(p, 0); 1233 if (dolock) 1234 KERNEL_UNLOCK(); 1235 1236 /* 1237 * If we are no longer being traced, or the parent 1238 * didn't give us a signal, look for more signals. 1239 */ 1240 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1241 continue; 1242 1243 /* 1244 * If the new signal is being masked, look for other 1245 * signals. 1246 */ 1247 signum = p->p_xstat; 1248 mask = sigmask(signum); 1249 if ((p->p_sigmask & mask) != 0) 1250 continue; 1251 1252 /* take the signal! */ 1253 atomic_clearbits_int(&p->p_siglist, mask); 1254 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 1255 } 1256 1257 prop = sigprop[signum]; 1258 1259 /* 1260 * Decide whether the signal should be returned. 1261 * Return the signal's number, or fall through 1262 * to clear it from the pending mask. 1263 */ 1264 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1265 case (long)SIG_DFL: 1266 /* 1267 * Don't take default actions on system processes. 1268 */ 1269 if (pr->ps_pid <= 1) { 1270 #ifdef DIAGNOSTIC 1271 /* 1272 * Are you sure you want to ignore SIGSEGV 1273 * in init? XXX 1274 */ 1275 printf("Process (pid %d) got signal" 1276 " %d\n", pr->ps_pid, signum); 1277 #endif 1278 break; /* == ignore */ 1279 } 1280 /* 1281 * If there is a pending stop signal to process 1282 * with default action, stop here, 1283 * then clear the signal. However, 1284 * if process is member of an orphaned 1285 * process group, ignore tty stop signals. 1286 */ 1287 if (prop & SA_STOP) { 1288 if (pr->ps_flags & PS_TRACED || 1289 (pr->ps_pgrp->pg_jobc == 0 && 1290 prop & SA_TTYSTOP)) 1291 break; /* == ignore */ 1292 p->p_xstat = signum; 1293 if (dolock) 1294 SCHED_LOCK(s); 1295 proc_stop(p, 1); 1296 if (dolock) 1297 SCHED_UNLOCK(s); 1298 break; 1299 } else if (prop & SA_IGNORE) { 1300 /* 1301 * Except for SIGCONT, shouldn't get here. 1302 * Default action is to ignore; drop it. 1303 */ 1304 break; /* == ignore */ 1305 } else 1306 goto keep; 1307 /*NOTREACHED*/ 1308 case (long)SIG_IGN: 1309 /* 1310 * Masking above should prevent us ever trying 1311 * to take action on an ignored signal other 1312 * than SIGCONT, unless process is traced. 1313 */ 1314 if ((prop & SA_CONT) == 0 && 1315 (pr->ps_flags & PS_TRACED) == 0) 1316 printf("issignal\n"); 1317 break; /* == ignore */ 1318 default: 1319 /* 1320 * This signal has an action, let 1321 * postsig() process it. 1322 */ 1323 goto keep; 1324 } 1325 } 1326 /* NOTREACHED */ 1327 1328 keep: 1329 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1330 return (signum); 1331 } 1332 1333 /* 1334 * Put the argument process into the stopped state and notify the parent 1335 * via wakeup. Signals are handled elsewhere. The process must not be 1336 * on the run queue. 1337 */ 1338 void 1339 proc_stop(struct proc *p, int sw) 1340 { 1341 struct process *pr = p->p_p; 1342 extern void *softclock_si; 1343 1344 #ifdef MULTIPROCESSOR 1345 SCHED_ASSERT_LOCKED(); 1346 #endif 1347 1348 p->p_stat = SSTOP; 1349 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1350 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1351 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1352 if (!timeout_pending(&proc_stop_to)) { 1353 timeout_add(&proc_stop_to, 0); 1354 /* 1355 * We need this soft interrupt to be handled fast. 1356 * Extra calls to softclock don't hurt. 1357 */ 1358 softintr_schedule(softclock_si); 1359 } 1360 if (sw) 1361 mi_switch(); 1362 } 1363 1364 /* 1365 * Called from a timeout to send signals to the parents of stopped processes. 1366 * We can't do this in proc_stop because it's called with nasty locks held 1367 * and we would need recursive scheduler lock to deal with that. 1368 */ 1369 void 1370 proc_stop_sweep(void *v) 1371 { 1372 struct process *pr; 1373 1374 LIST_FOREACH(pr, &allprocess, ps_list) { 1375 if ((pr->ps_flags & PS_STOPPED) == 0) 1376 continue; 1377 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1378 1379 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1380 prsignal(pr->ps_pptr, SIGCHLD); 1381 wakeup(pr->ps_pptr); 1382 } 1383 } 1384 1385 /* 1386 * Take the action for the specified signal 1387 * from the current set of pending signals. 1388 */ 1389 void 1390 postsig(struct proc *p, int signum) 1391 { 1392 struct process *pr = p->p_p; 1393 struct sigacts *ps = pr->ps_sigacts; 1394 sig_t action; 1395 u_long trapno; 1396 int mask, returnmask; 1397 siginfo_t si; 1398 union sigval sigval; 1399 int s, code; 1400 1401 KASSERT(signum != 0); 1402 KERNEL_ASSERT_LOCKED(); 1403 1404 mask = sigmask(signum); 1405 atomic_clearbits_int(&p->p_siglist, mask); 1406 action = ps->ps_sigact[signum]; 1407 sigval.sival_ptr = 0; 1408 1409 if (p->p_sisig != signum) { 1410 trapno = 0; 1411 code = SI_USER; 1412 sigval.sival_ptr = 0; 1413 } else { 1414 trapno = p->p_sitrapno; 1415 code = p->p_sicode; 1416 sigval = p->p_sigval; 1417 } 1418 initsiginfo(&si, signum, trapno, code, sigval); 1419 1420 #ifdef KTRACE 1421 if (KTRPOINT(p, KTR_PSIG)) { 1422 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1423 p->p_oldmask : p->p_sigmask, code, &si); 1424 } 1425 #endif 1426 if (action == SIG_DFL) { 1427 /* 1428 * Default action, where the default is to kill 1429 * the process. (Other cases were ignored above.) 1430 */ 1431 sigexit(p, signum); 1432 /* NOTREACHED */ 1433 } else { 1434 /* 1435 * If we get here, the signal must be caught. 1436 */ 1437 #ifdef DIAGNOSTIC 1438 if (action == SIG_IGN || (p->p_sigmask & mask)) 1439 panic("postsig action"); 1440 #endif 1441 /* 1442 * Set the new mask value and also defer further 1443 * occurrences of this signal. 1444 * 1445 * Special case: user has done a sigpause. Here the 1446 * current mask is not of interest, but rather the 1447 * mask from before the sigpause is what we want 1448 * restored after the signal processing is completed. 1449 */ 1450 #ifdef MULTIPROCESSOR 1451 s = splsched(); 1452 #else 1453 s = splhigh(); 1454 #endif 1455 if (p->p_flag & P_SIGSUSPEND) { 1456 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1457 returnmask = p->p_oldmask; 1458 } else { 1459 returnmask = p->p_sigmask; 1460 } 1461 if (p->p_sisig == signum) { 1462 p->p_sisig = 0; 1463 p->p_sitrapno = 0; 1464 p->p_sicode = SI_USER; 1465 p->p_sigval.sival_ptr = NULL; 1466 } 1467 1468 sendsig(action, signum, returnmask, &si); 1469 postsig_done(p, signum, ps); 1470 splx(s); 1471 } 1472 } 1473 1474 /* 1475 * Force the current process to exit with the specified signal, dumping core 1476 * if appropriate. We bypass the normal tests for masked and caught signals, 1477 * allowing unrecoverable failures to terminate the process without changing 1478 * signal state. Mark the accounting record with the signal termination. 1479 * If dumping core, save the signal number for the debugger. Calls exit and 1480 * does not return. 1481 */ 1482 void 1483 sigexit(struct proc *p, int signum) 1484 { 1485 /* Mark process as going away */ 1486 atomic_setbits_int(&p->p_flag, P_WEXIT); 1487 1488 p->p_p->ps_acflag |= AXSIG; 1489 if (sigprop[signum] & SA_CORE) { 1490 p->p_sisig = signum; 1491 1492 /* if there are other threads, pause them */ 1493 if (P_HASSIBLING(p)) 1494 single_thread_set(p, SINGLE_SUSPEND, 0); 1495 1496 if (coredump(p) == 0) 1497 signum |= WCOREFLAG; 1498 } 1499 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1500 /* NOTREACHED */ 1501 } 1502 1503 int nosuidcoredump = 1; 1504 1505 struct coredump_iostate { 1506 struct proc *io_proc; 1507 struct vnode *io_vp; 1508 struct ucred *io_cred; 1509 off_t io_offset; 1510 }; 1511 1512 /* 1513 * Dump core, into a file named "progname.core", unless the process was 1514 * setuid/setgid. 1515 */ 1516 int 1517 coredump(struct proc *p) 1518 { 1519 #ifdef SMALL_KERNEL 1520 return EPERM; 1521 #else 1522 struct process *pr = p->p_p; 1523 struct vnode *vp; 1524 struct ucred *cred = p->p_ucred; 1525 struct vmspace *vm = p->p_vmspace; 1526 struct nameidata nd; 1527 struct vattr vattr; 1528 struct coredump_iostate io; 1529 int error, len, incrash = 0; 1530 char *name; 1531 const char *dir = "/var/crash"; 1532 1533 if (pr->ps_emul->e_coredump == NULL) 1534 return (EINVAL); 1535 1536 pr->ps_flags |= PS_COREDUMP; 1537 1538 /* Don't dump if will exceed file size limit. */ 1539 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1540 return (EFBIG); 1541 1542 name = pool_get(&namei_pool, PR_WAITOK); 1543 1544 /* 1545 * If the process has inconsistent uids, nosuidcoredump 1546 * determines coredump placement policy. 1547 */ 1548 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1549 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1550 if (nosuidcoredump == 3) { 1551 /* 1552 * If the program directory does not exist, dumps of 1553 * that core will silently fail. 1554 */ 1555 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1556 dir, pr->ps_comm, pr->ps_pid); 1557 incrash = KERNELPATH; 1558 } else if (nosuidcoredump == 2) { 1559 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1560 dir, pr->ps_comm); 1561 incrash = KERNELPATH; 1562 } else { 1563 pool_put(&namei_pool, name); 1564 return (EPERM); 1565 } 1566 } else 1567 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1568 1569 if (len >= MAXPATHLEN) { 1570 pool_put(&namei_pool, name); 1571 return (EACCES); 1572 } 1573 1574 /* 1575 * Control the UID used to write out. The normal case uses 1576 * the real UID. If the sugid case is going to write into the 1577 * controlled directory, we do so as root. 1578 */ 1579 if (incrash == 0) { 1580 cred = crdup(cred); 1581 cred->cr_uid = cred->cr_ruid; 1582 cred->cr_gid = cred->cr_rgid; 1583 } else { 1584 if (p->p_fd->fd_rdir) { 1585 vrele(p->p_fd->fd_rdir); 1586 p->p_fd->fd_rdir = NULL; 1587 } 1588 p->p_ucred = crdup(p->p_ucred); 1589 crfree(cred); 1590 cred = p->p_ucred; 1591 crhold(cred); 1592 cred->cr_uid = 0; 1593 cred->cr_gid = 0; 1594 } 1595 1596 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1597 1598 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1599 S_IRUSR | S_IWUSR); 1600 1601 if (error) 1602 goto out; 1603 1604 /* 1605 * Don't dump to non-regular files, files with links, or files 1606 * owned by someone else. 1607 */ 1608 vp = nd.ni_vp; 1609 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1610 VOP_UNLOCK(vp); 1611 vn_close(vp, FWRITE, cred, p); 1612 goto out; 1613 } 1614 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1615 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1616 vattr.va_uid != cred->cr_uid) { 1617 error = EACCES; 1618 VOP_UNLOCK(vp); 1619 vn_close(vp, FWRITE, cred, p); 1620 goto out; 1621 } 1622 VATTR_NULL(&vattr); 1623 vattr.va_size = 0; 1624 VOP_SETATTR(vp, &vattr, cred, p); 1625 pr->ps_acflag |= ACORE; 1626 1627 io.io_proc = p; 1628 io.io_vp = vp; 1629 io.io_cred = cred; 1630 io.io_offset = 0; 1631 VOP_UNLOCK(vp); 1632 vref(vp); 1633 error = vn_close(vp, FWRITE, cred, p); 1634 if (error == 0) 1635 error = (*pr->ps_emul->e_coredump)(p, &io); 1636 vrele(vp); 1637 out: 1638 crfree(cred); 1639 pool_put(&namei_pool, name); 1640 return (error); 1641 #endif 1642 } 1643 1644 #ifndef SMALL_KERNEL 1645 int 1646 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1647 { 1648 struct coredump_iostate *io = cookie; 1649 off_t coffset = 0; 1650 size_t csize; 1651 int chunk, error; 1652 1653 csize = len; 1654 do { 1655 if (sigmask(SIGKILL) & 1656 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1657 return (EINTR); 1658 1659 /* Rest of the loop sleeps with lock held, so... */ 1660 yield(); 1661 1662 chunk = MIN(csize, MAXPHYS); 1663 error = vn_rdwr(UIO_WRITE, io->io_vp, 1664 (caddr_t)data + coffset, chunk, 1665 io->io_offset + coffset, segflg, 1666 IO_UNIT, io->io_cred, NULL, io->io_proc); 1667 if (error) { 1668 struct process *pr = io->io_proc->p_p; 1669 1670 if (error == ENOSPC) 1671 log(LOG_ERR, 1672 "coredump of %s(%d) failed, filesystem full\n", 1673 pr->ps_comm, pr->ps_pid); 1674 else 1675 log(LOG_ERR, 1676 "coredump of %s(%d), write failed: errno %d\n", 1677 pr->ps_comm, pr->ps_pid, error); 1678 return (error); 1679 } 1680 1681 coffset += chunk; 1682 csize -= chunk; 1683 } while (csize > 0); 1684 1685 io->io_offset += len; 1686 return (0); 1687 } 1688 1689 void 1690 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1691 { 1692 struct coredump_iostate *io = cookie; 1693 1694 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1695 } 1696 1697 #endif /* !SMALL_KERNEL */ 1698 1699 /* 1700 * Nonexistent system call-- signal process (may want to handle it). 1701 * Flag error in case process won't see signal immediately (blocked or ignored). 1702 */ 1703 int 1704 sys_nosys(struct proc *p, void *v, register_t *retval) 1705 { 1706 1707 ptsignal(p, SIGSYS, STHREAD); 1708 return (ENOSYS); 1709 } 1710 1711 int 1712 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1713 { 1714 static int sigwaitsleep; 1715 struct sys___thrsigdivert_args /* { 1716 syscallarg(sigset_t) sigmask; 1717 syscallarg(siginfo_t *) info; 1718 syscallarg(const struct timespec *) timeout; 1719 } */ *uap = v; 1720 struct process *pr = p->p_p; 1721 sigset_t *m; 1722 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1723 siginfo_t si; 1724 uint64_t to_ticks = 0; 1725 int timeinvalid = 0; 1726 int error = 0; 1727 1728 memset(&si, 0, sizeof(si)); 1729 1730 if (SCARG(uap, timeout) != NULL) { 1731 struct timespec ts; 1732 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1733 return (error); 1734 #ifdef KTRACE 1735 if (KTRPOINT(p, KTR_STRUCT)) 1736 ktrreltimespec(p, &ts); 1737 #endif 1738 if (!timespecisvalid(&ts)) 1739 timeinvalid = 1; 1740 else { 1741 to_ticks = (uint64_t)hz * ts.tv_sec + 1742 ts.tv_nsec / (tick * 1000); 1743 if (to_ticks > INT_MAX) 1744 to_ticks = INT_MAX; 1745 if (to_ticks == 0 && ts.tv_nsec) 1746 to_ticks = 1; 1747 } 1748 } 1749 1750 dosigsuspend(p, p->p_sigmask &~ mask); 1751 for (;;) { 1752 si.si_signo = CURSIG(p); 1753 if (si.si_signo != 0) { 1754 sigset_t smask = sigmask(si.si_signo); 1755 if (smask & mask) { 1756 if (p->p_siglist & smask) 1757 m = &p->p_siglist; 1758 else if (pr->ps_siglist & smask) 1759 m = &pr->ps_siglist; 1760 else { 1761 /* signal got eaten by someone else? */ 1762 continue; 1763 } 1764 atomic_clearbits_int(m, smask); 1765 error = 0; 1766 break; 1767 } 1768 } 1769 1770 /* per-POSIX, delay this error until after the above */ 1771 if (timeinvalid) 1772 error = EINVAL; 1773 1774 if (SCARG(uap, timeout) != NULL && to_ticks == 0) 1775 error = EAGAIN; 1776 1777 if (error != 0) 1778 break; 1779 1780 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1781 (int)to_ticks); 1782 } 1783 1784 if (error == 0) { 1785 *retval = si.si_signo; 1786 if (SCARG(uap, info) != NULL) 1787 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1788 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1789 /* 1790 * Restarting is wrong if there's a timeout, as it'll be 1791 * for the same interval again 1792 */ 1793 error = EINTR; 1794 } 1795 1796 return (error); 1797 } 1798 1799 void 1800 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1801 { 1802 memset(si, 0, sizeof(*si)); 1803 1804 si->si_signo = sig; 1805 si->si_code = code; 1806 if (code == SI_USER) { 1807 si->si_value = val; 1808 } else { 1809 switch (sig) { 1810 case SIGSEGV: 1811 case SIGILL: 1812 case SIGBUS: 1813 case SIGFPE: 1814 si->si_addr = val.sival_ptr; 1815 si->si_trapno = trapno; 1816 break; 1817 case SIGXFSZ: 1818 break; 1819 } 1820 } 1821 } 1822 1823 int 1824 filt_sigattach(struct knote *kn) 1825 { 1826 struct process *pr = curproc->p_p; 1827 1828 if (kn->kn_id >= NSIG) 1829 return EINVAL; 1830 1831 kn->kn_ptr.p_process = pr; 1832 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1833 1834 /* XXX lock the proc here while adding to the list? */ 1835 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1836 1837 return (0); 1838 } 1839 1840 void 1841 filt_sigdetach(struct knote *kn) 1842 { 1843 struct process *pr = kn->kn_ptr.p_process; 1844 1845 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1846 } 1847 1848 /* 1849 * signal knotes are shared with proc knotes, so we apply a mask to 1850 * the hint in order to differentiate them from process hints. This 1851 * could be avoided by using a signal-specific knote list, but probably 1852 * isn't worth the trouble. 1853 */ 1854 int 1855 filt_signal(struct knote *kn, long hint) 1856 { 1857 1858 if (hint & NOTE_SIGNAL) { 1859 hint &= ~NOTE_SIGNAL; 1860 1861 if (kn->kn_id == hint) 1862 kn->kn_data++; 1863 } 1864 return (kn->kn_data != 0); 1865 } 1866 1867 void 1868 userret(struct proc *p) 1869 { 1870 int signum; 1871 1872 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1873 if (p->p_flag & P_PROFPEND) { 1874 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1875 KERNEL_LOCK(); 1876 psignal(p, SIGPROF); 1877 KERNEL_UNLOCK(); 1878 } 1879 if (p->p_flag & P_ALRMPEND) { 1880 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1881 KERNEL_LOCK(); 1882 psignal(p, SIGVTALRM); 1883 KERNEL_UNLOCK(); 1884 } 1885 1886 if (SIGPENDING(p) != 0) { 1887 KERNEL_LOCK(); 1888 while ((signum = CURSIG(p)) != 0) 1889 postsig(p, signum); 1890 KERNEL_UNLOCK(); 1891 } 1892 1893 /* 1894 * If P_SIGSUSPEND is still set here, then we still need to restore 1895 * the original sigmask before returning to userspace. Also, this 1896 * might unmask some pending signals, so we need to check a second 1897 * time for signals to post. 1898 */ 1899 if (p->p_flag & P_SIGSUSPEND) { 1900 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1901 p->p_sigmask = p->p_oldmask; 1902 1903 KERNEL_LOCK(); 1904 while ((signum = CURSIG(p)) != 0) 1905 postsig(p, signum); 1906 KERNEL_UNLOCK(); 1907 } 1908 1909 if (p->p_flag & P_SUSPSINGLE) { 1910 KERNEL_LOCK(); 1911 single_thread_check(p, 0); 1912 KERNEL_UNLOCK(); 1913 } 1914 1915 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1916 1917 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1918 } 1919 1920 int 1921 single_thread_check(struct proc *p, int deep) 1922 { 1923 struct process *pr = p->p_p; 1924 1925 if (pr->ps_single != NULL && pr->ps_single != p) { 1926 do { 1927 int s; 1928 1929 /* if we're in deep, we need to unwind to the edge */ 1930 if (deep) { 1931 if (pr->ps_flags & PS_SINGLEUNWIND) 1932 return (ERESTART); 1933 if (pr->ps_flags & PS_SINGLEEXIT) 1934 return (EINTR); 1935 } 1936 1937 if (--pr->ps_singlecount == 0) 1938 wakeup(&pr->ps_singlecount); 1939 if (pr->ps_flags & PS_SINGLEEXIT) 1940 exit1(p, 0, EXIT_THREAD_NOCHECK); 1941 1942 /* not exiting and don't need to unwind, so suspend */ 1943 SCHED_LOCK(s); 1944 p->p_stat = SSTOP; 1945 mi_switch(); 1946 SCHED_UNLOCK(s); 1947 } while (pr->ps_single != NULL); 1948 } 1949 1950 return (0); 1951 } 1952 1953 /* 1954 * Stop other threads in the process. The mode controls how and 1955 * where the other threads should stop: 1956 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1957 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1958 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1959 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1960 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1961 * or released as with SINGLE_SUSPEND 1962 * - SINGLE_EXIT: unwind to kernel boundary and exit 1963 */ 1964 int 1965 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1966 { 1967 struct process *pr = p->p_p; 1968 struct proc *q; 1969 int error; 1970 1971 KERNEL_ASSERT_LOCKED(); 1972 1973 if ((error = single_thread_check(p, deep))) 1974 return error; 1975 1976 switch (mode) { 1977 case SINGLE_SUSPEND: 1978 case SINGLE_PTRACE: 1979 break; 1980 case SINGLE_UNWIND: 1981 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1982 break; 1983 case SINGLE_EXIT: 1984 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1985 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1986 break; 1987 #ifdef DIAGNOSTIC 1988 default: 1989 panic("single_thread_mode = %d", mode); 1990 #endif 1991 } 1992 pr->ps_single = p; 1993 pr->ps_singlecount = 0; 1994 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1995 int s; 1996 1997 if (q == p) 1998 continue; 1999 if (q->p_flag & P_WEXIT) { 2000 if (mode == SINGLE_EXIT) { 2001 SCHED_LOCK(s); 2002 if (q->p_stat == SSTOP) { 2003 setrunnable(q); 2004 pr->ps_singlecount++; 2005 } 2006 SCHED_UNLOCK(s); 2007 } 2008 continue; 2009 } 2010 SCHED_LOCK(s); 2011 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2012 switch (q->p_stat) { 2013 case SIDL: 2014 case SRUN: 2015 pr->ps_singlecount++; 2016 break; 2017 case SSLEEP: 2018 /* if it's not interruptible, then just have to wait */ 2019 if (q->p_flag & P_SINTR) { 2020 /* merely need to suspend? just stop it */ 2021 if (mode == SINGLE_SUSPEND || 2022 mode == SINGLE_PTRACE) { 2023 q->p_stat = SSTOP; 2024 break; 2025 } 2026 /* need to unwind or exit, so wake it */ 2027 setrunnable(q); 2028 } 2029 pr->ps_singlecount++; 2030 break; 2031 case SSTOP: 2032 if (mode == SINGLE_EXIT) { 2033 setrunnable(q); 2034 pr->ps_singlecount++; 2035 } 2036 break; 2037 case SDEAD: 2038 break; 2039 case SONPROC: 2040 pr->ps_singlecount++; 2041 signotify(q); 2042 break; 2043 } 2044 SCHED_UNLOCK(s); 2045 } 2046 2047 if (mode != SINGLE_PTRACE) 2048 single_thread_wait(pr); 2049 2050 return 0; 2051 } 2052 2053 void 2054 single_thread_wait(struct process *pr) 2055 { 2056 /* wait until they're all suspended */ 2057 while (pr->ps_singlecount > 0) 2058 tsleep(&pr->ps_singlecount, PWAIT, "suspend", 0); 2059 } 2060 2061 void 2062 single_thread_clear(struct proc *p, int flag) 2063 { 2064 struct process *pr = p->p_p; 2065 struct proc *q; 2066 2067 KASSERT(pr->ps_single == p); 2068 KERNEL_ASSERT_LOCKED(); 2069 2070 pr->ps_single = NULL; 2071 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2072 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2073 int s; 2074 2075 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2076 continue; 2077 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2078 2079 /* 2080 * if the thread was only stopped for single threading 2081 * then clearing that either makes it runnable or puts 2082 * it back into some sleep queue 2083 */ 2084 SCHED_LOCK(s); 2085 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2086 if (q->p_wchan == 0) 2087 setrunnable(q); 2088 else 2089 q->p_stat = SSLEEP; 2090 } 2091 SCHED_UNLOCK(s); 2092 } 2093 } 2094 2095 void 2096 sigio_del(struct sigiolst *rmlist) 2097 { 2098 struct sigio *sigio; 2099 2100 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2101 LIST_REMOVE(sigio, sio_pgsigio); 2102 crfree(sigio->sio_ucred); 2103 free(sigio, M_SIGIO, sizeof(*sigio)); 2104 } 2105 } 2106 2107 void 2108 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2109 { 2110 struct sigio *sigio; 2111 2112 MUTEX_ASSERT_LOCKED(&sigio_lock); 2113 2114 sigio = sir->sir_sigio; 2115 if (sigio != NULL) { 2116 KASSERT(sigio->sio_myref == sir); 2117 sir->sir_sigio = NULL; 2118 2119 if (sigio->sio_pgid > 0) 2120 sigio->sio_proc = NULL; 2121 else 2122 sigio->sio_pgrp = NULL; 2123 LIST_REMOVE(sigio, sio_pgsigio); 2124 2125 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2126 } 2127 } 2128 2129 void 2130 sigio_free(struct sigio_ref *sir) 2131 { 2132 struct sigiolst rmlist; 2133 2134 if (sir->sir_sigio == NULL) 2135 return; 2136 2137 LIST_INIT(&rmlist); 2138 2139 mtx_enter(&sigio_lock); 2140 sigio_unlink(sir, &rmlist); 2141 mtx_leave(&sigio_lock); 2142 2143 sigio_del(&rmlist); 2144 } 2145 2146 void 2147 sigio_freelist(struct sigiolst *sigiolst) 2148 { 2149 struct sigiolst rmlist; 2150 struct sigio *sigio; 2151 2152 if (LIST_EMPTY(sigiolst)) 2153 return; 2154 2155 LIST_INIT(&rmlist); 2156 2157 mtx_enter(&sigio_lock); 2158 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2159 sigio_unlink(sigio->sio_myref, &rmlist); 2160 mtx_leave(&sigio_lock); 2161 2162 sigio_del(&rmlist); 2163 } 2164 2165 int 2166 sigio_setown(struct sigio_ref *sir, pid_t pgid) 2167 { 2168 struct sigiolst rmlist; 2169 struct proc *p = curproc; 2170 struct pgrp *pgrp = NULL; 2171 struct process *pr = NULL; 2172 struct sigio *sigio; 2173 int error; 2174 2175 if (pgid == 0) { 2176 sigio_free(sir); 2177 return (0); 2178 } 2179 2180 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2181 sigio->sio_pgid = pgid; 2182 sigio->sio_ucred = crhold(p->p_ucred); 2183 sigio->sio_myref = sir; 2184 2185 LIST_INIT(&rmlist); 2186 2187 /* 2188 * The kernel lock, and not sleeping between prfind()/pgfind() and 2189 * linking of the sigio ensure that the process or process group does 2190 * not disappear unexpectedly. 2191 */ 2192 KERNEL_LOCK(); 2193 mtx_enter(&sigio_lock); 2194 2195 if (pgid > 0) { 2196 pr = prfind(pgid); 2197 if (pr == NULL) { 2198 error = ESRCH; 2199 goto fail; 2200 } 2201 2202 /* 2203 * Policy - Don't allow a process to FSETOWN a process 2204 * in another session. 2205 * 2206 * Remove this test to allow maximum flexibility or 2207 * restrict FSETOWN to the current process or process 2208 * group for maximum safety. 2209 */ 2210 if (pr->ps_session != p->p_p->ps_session) { 2211 error = EPERM; 2212 goto fail; 2213 } 2214 2215 if ((pr->ps_flags & PS_EXITING) != 0) { 2216 error = ESRCH; 2217 goto fail; 2218 } 2219 } else /* if (pgid < 0) */ { 2220 pgrp = pgfind(-pgid); 2221 if (pgrp == NULL) { 2222 error = ESRCH; 2223 goto fail; 2224 } 2225 2226 /* 2227 * Policy - Don't allow a process to FSETOWN a process 2228 * in another session. 2229 * 2230 * Remove this test to allow maximum flexibility or 2231 * restrict FSETOWN to the current process or process 2232 * group for maximum safety. 2233 */ 2234 if (pgrp->pg_session != p->p_p->ps_session) { 2235 error = EPERM; 2236 goto fail; 2237 } 2238 } 2239 2240 if (pgid > 0) { 2241 sigio->sio_proc = pr; 2242 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2243 } else { 2244 sigio->sio_pgrp = pgrp; 2245 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2246 } 2247 2248 sigio_unlink(sir, &rmlist); 2249 sir->sir_sigio = sigio; 2250 2251 mtx_leave(&sigio_lock); 2252 KERNEL_UNLOCK(); 2253 2254 sigio_del(&rmlist); 2255 2256 return (0); 2257 2258 fail: 2259 mtx_leave(&sigio_lock); 2260 KERNEL_UNLOCK(); 2261 2262 crfree(sigio->sio_ucred); 2263 free(sigio, M_SIGIO, sizeof(*sigio)); 2264 2265 return (error); 2266 } 2267 2268 pid_t 2269 sigio_getown(struct sigio_ref *sir) 2270 { 2271 struct sigio *sigio; 2272 pid_t pgid = 0; 2273 2274 mtx_enter(&sigio_lock); 2275 sigio = sir->sir_sigio; 2276 if (sigio != NULL) 2277 pgid = sigio->sio_pgid; 2278 mtx_leave(&sigio_lock); 2279 2280 return (pgid); 2281 } 2282 2283 void 2284 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2285 { 2286 struct sigiolst rmlist; 2287 struct sigio *newsigio, *sigio; 2288 2289 sigio_free(dst); 2290 2291 if (src->sir_sigio == NULL) 2292 return; 2293 2294 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2295 LIST_INIT(&rmlist); 2296 2297 mtx_enter(&sigio_lock); 2298 2299 sigio = src->sir_sigio; 2300 if (sigio == NULL) { 2301 mtx_leave(&sigio_lock); 2302 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2303 return; 2304 } 2305 2306 newsigio->sio_pgid = sigio->sio_pgid; 2307 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2308 newsigio->sio_myref = dst; 2309 if (newsigio->sio_pgid > 0) { 2310 newsigio->sio_proc = sigio->sio_proc; 2311 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2312 sio_pgsigio); 2313 } else { 2314 newsigio->sio_pgrp = sigio->sio_pgrp; 2315 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2316 sio_pgsigio); 2317 } 2318 2319 sigio_unlink(dst, &rmlist); 2320 dst->sir_sigio = newsigio; 2321 2322 mtx_leave(&sigio_lock); 2323 2324 sigio_del(&rmlist); 2325 } 2326