1 /* $OpenBSD: kern_sig.c,v 1.225 2018/11/12 15:09:17 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 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 if (signum != SIGCONT) 369 ps->ps_sigignore |= bit; /* easier in psignal */ 370 ps->ps_sigcatch &= ~bit; 371 } else { 372 ps->ps_sigignore &= ~bit; 373 if (sa->sa_handler == SIG_DFL) 374 ps->ps_sigcatch &= ~bit; 375 else 376 ps->ps_sigcatch |= bit; 377 } 378 splx(s); 379 } 380 381 /* 382 * Initialize signal state for process 0; 383 * set to ignore signals that are ignored by default. 384 */ 385 void 386 siginit(struct process *pr) 387 { 388 struct sigacts *ps = pr->ps_sigacts; 389 int i; 390 391 for (i = 0; i < NSIG; i++) 392 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 393 ps->ps_sigignore |= sigmask(i); 394 ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 395 } 396 397 /* 398 * Reset signals for an exec by the specified thread. 399 */ 400 void 401 execsigs(struct proc *p) 402 { 403 struct sigacts *ps; 404 int nc, mask; 405 406 sigactsunshare(p->p_p); 407 ps = p->p_p->ps_sigacts; 408 409 /* 410 * Reset caught signals. Held signals remain held 411 * through p_sigmask (unless they were caught, 412 * and are now ignored by default). 413 */ 414 while (ps->ps_sigcatch) { 415 nc = ffs((long)ps->ps_sigcatch); 416 mask = sigmask(nc); 417 ps->ps_sigcatch &= ~mask; 418 if (sigprop[nc] & SA_IGNORE) { 419 if (nc != SIGCONT) 420 ps->ps_sigignore |= mask; 421 atomic_clearbits_int(&p->p_siglist, mask); 422 } 423 ps->ps_sigact[nc] = SIG_DFL; 424 } 425 /* 426 * Reset stack state to the user stack. 427 * Clear set of signals caught on the signal stack. 428 */ 429 sigstkinit(&p->p_sigstk); 430 ps->ps_flags &= ~SAS_NOCLDWAIT; 431 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 432 ps->ps_sigact[SIGCHLD] = SIG_DFL; 433 } 434 435 /* 436 * Manipulate signal mask. 437 * Note that we receive new mask, not pointer, 438 * and return old mask as return value; 439 * the library stub does the rest. 440 */ 441 int 442 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 443 { 444 struct sys_sigprocmask_args /* { 445 syscallarg(int) how; 446 syscallarg(sigset_t) mask; 447 } */ *uap = v; 448 int error = 0; 449 sigset_t mask; 450 451 *retval = p->p_sigmask; 452 mask = SCARG(uap, mask) &~ sigcantmask; 453 454 switch (SCARG(uap, how)) { 455 case SIG_BLOCK: 456 atomic_setbits_int(&p->p_sigmask, mask); 457 break; 458 case SIG_UNBLOCK: 459 atomic_clearbits_int(&p->p_sigmask, mask); 460 break; 461 case SIG_SETMASK: 462 p->p_sigmask = mask; 463 break; 464 default: 465 error = EINVAL; 466 break; 467 } 468 return (error); 469 } 470 471 int 472 sys_sigpending(struct proc *p, void *v, register_t *retval) 473 { 474 475 *retval = p->p_siglist; 476 return (0); 477 } 478 479 /* 480 * Temporarily replace calling proc's signal mask for the duration of a 481 * system call. Original signal mask will be restored by userret(). 482 */ 483 void 484 dosigsuspend(struct proc *p, sigset_t newmask) 485 { 486 KASSERT(p == curproc); 487 488 p->p_oldmask = p->p_sigmask; 489 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 490 p->p_sigmask = newmask; 491 } 492 493 /* 494 * Suspend process until signal, providing mask to be set 495 * in the meantime. Note nonstandard calling convention: 496 * libc stub passes mask, not pointer, to save a copyin. 497 */ 498 int 499 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 500 { 501 struct sys_sigsuspend_args /* { 502 syscallarg(int) mask; 503 } */ *uap = v; 504 struct process *pr = p->p_p; 505 struct sigacts *ps = pr->ps_sigacts; 506 507 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 508 while (tsleep(ps, PPAUSE|PCATCH, "pause", 0) == 0) 509 /* void */; 510 /* always return EINTR rather than ERESTART... */ 511 return (EINTR); 512 } 513 514 int 515 sigonstack(size_t stack) 516 { 517 const struct sigaltstack *ss = &curproc->p_sigstk; 518 519 return (ss->ss_flags & SS_DISABLE ? 0 : 520 (stack - (size_t)ss->ss_sp < ss->ss_size)); 521 } 522 523 int 524 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 525 { 526 struct sys_sigaltstack_args /* { 527 syscallarg(const struct sigaltstack *) nss; 528 syscallarg(struct sigaltstack *) oss; 529 } */ *uap = v; 530 struct sigaltstack ss; 531 const struct sigaltstack *nss; 532 struct sigaltstack *oss; 533 int onstack = sigonstack(PROC_STACK(p)); 534 int error; 535 536 nss = SCARG(uap, nss); 537 oss = SCARG(uap, oss); 538 539 if (oss != NULL) { 540 ss = p->p_sigstk; 541 if (onstack) 542 ss.ss_flags |= SS_ONSTACK; 543 if ((error = copyout(&ss, oss, sizeof(ss)))) 544 return (error); 545 } 546 if (nss == NULL) 547 return (0); 548 error = copyin(nss, &ss, sizeof(ss)); 549 if (error) 550 return (error); 551 if (onstack) 552 return (EPERM); 553 if (ss.ss_flags & ~SS_DISABLE) 554 return (EINVAL); 555 if (ss.ss_flags & SS_DISABLE) { 556 p->p_sigstk.ss_flags = ss.ss_flags; 557 return (0); 558 } 559 if (ss.ss_size < MINSIGSTKSZ) 560 return (ENOMEM); 561 562 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 563 if (error) 564 return (error); 565 566 p->p_sigstk = ss; 567 return (0); 568 } 569 570 int 571 sys_kill(struct proc *cp, void *v, register_t *retval) 572 { 573 struct sys_kill_args /* { 574 syscallarg(int) pid; 575 syscallarg(int) signum; 576 } */ *uap = v; 577 struct process *pr; 578 int pid = SCARG(uap, pid); 579 int signum = SCARG(uap, signum); 580 int error; 581 int zombie = 0; 582 583 if ((error = pledge_kill(cp, pid)) != 0) 584 return (error); 585 if (((u_int)signum) >= NSIG) 586 return (EINVAL); 587 if (pid > 0) { 588 if ((pr = prfind(pid)) == NULL) { 589 if ((pr = zombiefind(pid)) == NULL) 590 return (ESRCH); 591 else 592 zombie = 1; 593 } 594 if (!cansignal(cp, pr, signum)) 595 return (EPERM); 596 597 /* kill single process */ 598 if (signum && !zombie) 599 prsignal(pr, signum); 600 return (0); 601 } 602 switch (pid) { 603 case -1: /* broadcast signal */ 604 return (killpg1(cp, signum, 0, 1)); 605 case 0: /* signal own process group */ 606 return (killpg1(cp, signum, 0, 0)); 607 default: /* negative explicit process group */ 608 return (killpg1(cp, signum, -pid, 0)); 609 } 610 } 611 612 int 613 sys_thrkill(struct proc *cp, void *v, register_t *retval) 614 { 615 struct sys_thrkill_args /* { 616 syscallarg(pid_t) tid; 617 syscallarg(int) signum; 618 syscallarg(void *) tcb; 619 } */ *uap = v; 620 struct proc *p; 621 int tid = SCARG(uap, tid); 622 int signum = SCARG(uap, signum); 623 void *tcb; 624 625 if (((u_int)signum) >= NSIG) 626 return (EINVAL); 627 if (tid > THREAD_PID_OFFSET) { 628 if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL) 629 return (ESRCH); 630 631 /* can only kill threads in the same process */ 632 if (p->p_p != cp->p_p) 633 return (ESRCH); 634 } else if (tid == 0) 635 p = cp; 636 else 637 return (EINVAL); 638 639 /* optionally require the target thread to have the given tcb addr */ 640 tcb = SCARG(uap, tcb); 641 if (tcb != NULL && tcb != TCB_GET(p)) 642 return (ESRCH); 643 644 if (signum) 645 ptsignal(p, signum, STHREAD); 646 return (0); 647 } 648 649 /* 650 * Common code for kill process group/broadcast kill. 651 * cp is calling process. 652 */ 653 int 654 killpg1(struct proc *cp, int signum, int pgid, int all) 655 { 656 struct process *pr; 657 struct pgrp *pgrp; 658 int nfound = 0; 659 660 if (all) { 661 /* 662 * broadcast 663 */ 664 LIST_FOREACH(pr, &allprocess, ps_list) { 665 if (pr->ps_pid <= 1 || 666 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 667 pr == cp->p_p || !cansignal(cp, pr, signum)) 668 continue; 669 nfound++; 670 if (signum) 671 prsignal(pr, signum); 672 } 673 } else { 674 if (pgid == 0) 675 /* 676 * zero pgid means send to my process group. 677 */ 678 pgrp = cp->p_p->ps_pgrp; 679 else { 680 pgrp = pgfind(pgid); 681 if (pgrp == NULL) 682 return (ESRCH); 683 } 684 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 685 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 686 !cansignal(cp, pr, signum)) 687 continue; 688 nfound++; 689 if (signum) 690 prsignal(pr, signum); 691 } 692 } 693 return (nfound ? 0 : ESRCH); 694 } 695 696 #define CANDELIVER(uid, euid, pr) \ 697 (euid == 0 || \ 698 (uid) == (pr)->ps_ucred->cr_ruid || \ 699 (uid) == (pr)->ps_ucred->cr_svuid || \ 700 (uid) == (pr)->ps_ucred->cr_uid || \ 701 (euid) == (pr)->ps_ucred->cr_ruid || \ 702 (euid) == (pr)->ps_ucred->cr_svuid || \ 703 (euid) == (pr)->ps_ucred->cr_uid) 704 705 #define CANSIGIO(cr, pr) \ 706 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 707 708 /* 709 * Deliver signum to pgid, but first check uid/euid against each 710 * process and see if it is permitted. 711 */ 712 void 713 csignal(pid_t pgid, int signum, uid_t uid, uid_t euid) 714 { 715 struct pgrp *pgrp; 716 struct process *pr; 717 718 if (pgid == 0) 719 return; 720 if (pgid < 0) { 721 pgid = -pgid; 722 if ((pgrp = pgfind(pgid)) == NULL) 723 return; 724 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 725 if (CANDELIVER(uid, euid, pr)) 726 prsignal(pr, signum); 727 } else { 728 if ((pr = prfind(pgid)) == NULL) 729 return; 730 if (CANDELIVER(uid, euid, pr)) 731 prsignal(pr, signum); 732 } 733 } 734 735 /* 736 * Send a signal to a process group. 737 */ 738 void 739 gsignal(int pgid, int signum) 740 { 741 struct pgrp *pgrp; 742 743 if (pgid && (pgrp = pgfind(pgid))) 744 pgsignal(pgrp, signum, 0); 745 } 746 747 /* 748 * Send a signal to a process group. If checktty is 1, 749 * limit to members which have a controlling terminal. 750 */ 751 void 752 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 753 { 754 struct process *pr; 755 756 if (pgrp) 757 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 758 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 759 prsignal(pr, signum); 760 } 761 762 /* 763 * Send a SIGIO or SIGURG signal to a process or process group using stored 764 * credentials rather than those of the current process. 765 */ 766 void 767 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 768 { 769 struct process *pr; 770 struct sigio *sigio; 771 772 if (sir->sir_sigio == NULL) 773 return; 774 775 mtx_enter(&sigio_lock); 776 sigio = sir->sir_sigio; 777 if (sigio == NULL) 778 goto out; 779 if (sigio->sio_pgid > 0) { 780 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 781 prsignal(sigio->sio_proc, sig); 782 } else if (sigio->sio_pgid < 0) { 783 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 784 if (CANSIGIO(sigio->sio_ucred, pr) && 785 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 786 prsignal(pr, sig); 787 } 788 } 789 out: 790 mtx_leave(&sigio_lock); 791 } 792 793 /* 794 * Recalculate the signal mask and reset the signal disposition after 795 * usermode frame for delivery is formed. 796 */ 797 void 798 postsig_done(struct proc *p, int signum, struct sigacts *ps) 799 { 800 int mask = sigmask(signum); 801 802 KERNEL_ASSERT_LOCKED(); 803 804 p->p_ru.ru_nsignals++; 805 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 806 if ((ps->ps_sigreset & mask) != 0) { 807 ps->ps_sigcatch &= ~mask; 808 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 809 ps->ps_sigignore |= mask; 810 ps->ps_sigact[signum] = SIG_DFL; 811 } 812 } 813 814 /* 815 * Send a signal caused by a trap to the current thread 816 * If it will be caught immediately, deliver it with correct code. 817 * Otherwise, post it normally. 818 */ 819 void 820 trapsignal(struct proc *p, int signum, u_long trapno, int code, 821 union sigval sigval) 822 { 823 struct process *pr = p->p_p; 824 struct sigacts *ps = pr->ps_sigacts; 825 int mask; 826 827 switch (signum) { 828 case SIGILL: 829 case SIGBUS: 830 case SIGSEGV: 831 pr->ps_acflag |= ATRAP; 832 break; 833 } 834 835 mask = sigmask(signum); 836 if ((pr->ps_flags & PS_TRACED) == 0 && 837 (ps->ps_sigcatch & mask) != 0 && 838 (p->p_sigmask & mask) == 0) { 839 siginfo_t si; 840 initsiginfo(&si, signum, trapno, code, sigval); 841 #ifdef KTRACE 842 if (KTRPOINT(p, KTR_PSIG)) { 843 ktrpsig(p, signum, ps->ps_sigact[signum], 844 p->p_sigmask, code, &si); 845 } 846 #endif 847 sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si); 848 postsig_done(p, signum, ps); 849 } else { 850 p->p_sisig = signum; 851 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 852 p->p_sicode = code; 853 p->p_sigval = sigval; 854 855 /* 856 * Signals like SIGBUS and SIGSEGV should not, when 857 * generated by the kernel, be ignorable or blockable. 858 * If it is and we're not being traced, then just kill 859 * the process. 860 */ 861 if ((pr->ps_flags & PS_TRACED) == 0 && 862 (sigprop[signum] & SA_KILL) && 863 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 864 sigexit(p, signum); 865 ptsignal(p, signum, STHREAD); 866 } 867 } 868 869 /* 870 * Send the signal to the process. If the signal has an action, the action 871 * is usually performed by the target process rather than the caller; we add 872 * the signal to the set of pending signals for the process. 873 * 874 * Exceptions: 875 * o When a stop signal is sent to a sleeping process that takes the 876 * default action, the process is stopped without awakening it. 877 * o SIGCONT restarts stopped processes (or puts them back to sleep) 878 * regardless of the signal action (eg, blocked or ignored). 879 * 880 * Other ignored signals are discarded immediately. 881 */ 882 void 883 psignal(struct proc *p, int signum) 884 { 885 ptsignal(p, signum, SPROCESS); 886 } 887 888 /* 889 * type = SPROCESS process signal, can be diverted (sigwait()) 890 * XXX if blocked in all threads, mark as pending in struct process 891 * type = STHREAD thread signal, but should be propagated if unhandled 892 * type = SPROPAGATED propagated to this thread, so don't propagate again 893 */ 894 void 895 ptsignal(struct proc *p, int signum, enum signal_type type) 896 { 897 int s, prop; 898 sig_t action; 899 int mask; 900 struct process *pr = p->p_p; 901 struct proc *q; 902 int wakeparent = 0; 903 904 #ifdef DIAGNOSTIC 905 if ((u_int)signum >= NSIG || signum == 0) 906 panic("psignal signal number"); 907 #endif 908 909 /* Ignore signal if the target process is exiting */ 910 if (pr->ps_flags & PS_EXITING) 911 return; 912 913 mask = sigmask(signum); 914 915 if (type == SPROCESS) { 916 /* Accept SIGKILL to coredumping processes */ 917 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 918 if (pr->ps_single != NULL) 919 p = pr->ps_single; 920 atomic_setbits_int(&p->p_siglist, mask); 921 return; 922 } 923 924 /* 925 * If the current thread can process the signal 926 * immediately (it's unblocked) then have it take it. 927 */ 928 q = curproc; 929 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 930 (q->p_sigmask & mask) == 0) 931 p = q; 932 else { 933 /* 934 * A process-wide signal can be diverted to a 935 * different thread that's in sigwait() for this 936 * signal. If there isn't such a thread, then 937 * pick a thread that doesn't have it blocked so 938 * that the stop/kill consideration isn't 939 * delayed. Otherwise, mark it pending on the 940 * main thread. 941 */ 942 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 943 /* ignore exiting threads */ 944 if (q->p_flag & P_WEXIT) 945 continue; 946 947 /* skip threads that have the signal blocked */ 948 if ((q->p_sigmask & mask) != 0) 949 continue; 950 951 /* okay, could send to this thread */ 952 p = q; 953 954 /* 955 * sigsuspend, sigwait, ppoll/pselect, etc? 956 * Definitely go to this thread, as it's 957 * already blocked in the kernel. 958 */ 959 if (q->p_flag & P_SIGSUSPEND) 960 break; 961 } 962 } 963 } 964 965 if (type != SPROPAGATED) 966 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 967 968 prop = sigprop[signum]; 969 970 /* 971 * If proc is traced, always give parent a chance. 972 */ 973 if (pr->ps_flags & PS_TRACED) { 974 action = SIG_DFL; 975 atomic_setbits_int(&p->p_siglist, mask); 976 } else { 977 /* 978 * If the signal is being ignored, 979 * then we forget about it immediately. 980 * (Note: we don't set SIGCONT in ps_sigignore, 981 * and if it is set to SIG_IGN, 982 * action will be SIG_DFL here.) 983 */ 984 if (pr->ps_sigacts->ps_sigignore & mask) 985 return; 986 if (p->p_sigmask & mask) { 987 action = SIG_HOLD; 988 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 989 action = SIG_CATCH; 990 } else { 991 action = SIG_DFL; 992 993 if (prop & SA_KILL && pr->ps_nice > NZERO) 994 pr->ps_nice = NZERO; 995 996 /* 997 * If sending a tty stop signal to a member of an 998 * orphaned process group, discard the signal here if 999 * the action is default; don't stop the process below 1000 * if sleeping, and don't clear any pending SIGCONT. 1001 */ 1002 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1003 return; 1004 } 1005 1006 atomic_setbits_int(&p->p_siglist, mask); 1007 } 1008 1009 if (prop & SA_CONT) 1010 atomic_clearbits_int(&p->p_siglist, stopsigmask); 1011 1012 if (prop & SA_STOP) { 1013 atomic_clearbits_int(&p->p_siglist, contsigmask); 1014 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1015 } 1016 1017 /* 1018 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1019 */ 1020 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1021 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1022 if (q != p) 1023 ptsignal(q, signum, SPROPAGATED); 1024 1025 /* 1026 * Defer further processing for signals which are held, 1027 * except that stopped processes must be continued by SIGCONT. 1028 */ 1029 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 1030 return; 1031 1032 SCHED_LOCK(s); 1033 1034 switch (p->p_stat) { 1035 1036 case SSLEEP: 1037 /* 1038 * If process is sleeping uninterruptibly 1039 * we can't interrupt the sleep... the signal will 1040 * be noticed when the process returns through 1041 * trap() or syscall(). 1042 */ 1043 if ((p->p_flag & P_SINTR) == 0) 1044 goto out; 1045 /* 1046 * Process is sleeping and traced... make it runnable 1047 * so it can discover the signal in issignal() and stop 1048 * for the parent. 1049 */ 1050 if (pr->ps_flags & PS_TRACED) 1051 goto run; 1052 /* 1053 * If SIGCONT is default (or ignored) and process is 1054 * asleep, we are finished; the process should not 1055 * be awakened. 1056 */ 1057 if ((prop & SA_CONT) && action == SIG_DFL) { 1058 atomic_clearbits_int(&p->p_siglist, mask); 1059 goto out; 1060 } 1061 /* 1062 * When a sleeping process receives a stop 1063 * signal, process immediately if possible. 1064 */ 1065 if ((prop & SA_STOP) && action == SIG_DFL) { 1066 /* 1067 * If a child holding parent blocked, 1068 * stopping could cause deadlock. 1069 */ 1070 if (pr->ps_flags & PS_PPWAIT) 1071 goto out; 1072 atomic_clearbits_int(&p->p_siglist, mask); 1073 p->p_xstat = signum; 1074 proc_stop(p, 0); 1075 goto out; 1076 } 1077 /* 1078 * All other (caught or default) signals 1079 * cause the process to run. 1080 */ 1081 goto runfast; 1082 /*NOTREACHED*/ 1083 1084 case SSTOP: 1085 /* 1086 * If traced process is already stopped, 1087 * then no further action is necessary. 1088 */ 1089 if (pr->ps_flags & PS_TRACED) 1090 goto out; 1091 1092 /* 1093 * Kill signal always sets processes running. 1094 */ 1095 if (signum == SIGKILL) { 1096 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1097 goto runfast; 1098 } 1099 1100 if (prop & SA_CONT) { 1101 /* 1102 * If SIGCONT is default (or ignored), we continue the 1103 * process but don't leave the signal in p_siglist, as 1104 * it has no further action. If SIGCONT is held, we 1105 * continue the process and leave the signal in 1106 * p_siglist. If the process catches SIGCONT, let it 1107 * handle the signal itself. If it isn't waiting on 1108 * an event, then it goes back to run state. 1109 * Otherwise, process goes back to sleep state. 1110 */ 1111 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1112 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1113 wakeparent = 1; 1114 if (action == SIG_DFL) 1115 atomic_clearbits_int(&p->p_siglist, mask); 1116 if (action == SIG_CATCH) 1117 goto runfast; 1118 if (p->p_wchan == 0) 1119 goto run; 1120 p->p_stat = SSLEEP; 1121 goto out; 1122 } 1123 1124 if (prop & SA_STOP) { 1125 /* 1126 * Already stopped, don't need to stop again. 1127 * (If we did the shell could get confused.) 1128 */ 1129 atomic_clearbits_int(&p->p_siglist, mask); 1130 goto out; 1131 } 1132 1133 /* 1134 * If process is sleeping interruptibly, then simulate a 1135 * wakeup so that when it is continued, it will be made 1136 * runnable and can look at the signal. But don't make 1137 * the process runnable, leave it stopped. 1138 */ 1139 if (p->p_wchan && p->p_flag & P_SINTR) 1140 unsleep(p); 1141 goto out; 1142 1143 case SONPROC: 1144 signotify(p); 1145 /* FALLTHROUGH */ 1146 default: 1147 /* 1148 * SRUN, SIDL, SDEAD do nothing with the signal, 1149 * other than kicking ourselves if we are running. 1150 * It will either never be noticed, or noticed very soon. 1151 */ 1152 goto out; 1153 } 1154 /*NOTREACHED*/ 1155 1156 runfast: 1157 /* 1158 * Raise priority to at least PUSER. 1159 */ 1160 if (p->p_priority > PUSER) 1161 p->p_priority = PUSER; 1162 run: 1163 setrunnable(p); 1164 out: 1165 SCHED_UNLOCK(s); 1166 if (wakeparent) 1167 wakeup(pr->ps_pptr); 1168 } 1169 1170 /* 1171 * If the current process has received a signal (should be caught or cause 1172 * termination, should interrupt current syscall), return the signal number. 1173 * Stop signals with default action are processed immediately, then cleared; 1174 * they aren't returned. This is checked after each entry to the system for 1175 * a syscall or trap (though this can usually be done without calling issignal 1176 * by checking the pending signal masks in the CURSIG macro.) The normal call 1177 * sequence is 1178 * 1179 * while (signum = CURSIG(curproc)) 1180 * postsig(signum); 1181 * 1182 * Assumes that if the P_SINTR flag is set, we're holding both the 1183 * kernel and scheduler locks. 1184 */ 1185 int 1186 issignal(struct proc *p) 1187 { 1188 struct process *pr = p->p_p; 1189 int signum, mask, prop; 1190 int dolock = (p->p_flag & P_SINTR) == 0; 1191 int s; 1192 1193 for (;;) { 1194 mask = p->p_siglist & ~p->p_sigmask; 1195 if (pr->ps_flags & PS_PPWAIT) 1196 mask &= ~stopsigmask; 1197 if (mask == 0) /* no signal to send */ 1198 return (0); 1199 signum = ffs((long)mask); 1200 mask = sigmask(signum); 1201 atomic_clearbits_int(&p->p_siglist, mask); 1202 1203 /* 1204 * We should see pending but ignored signals 1205 * only if PS_TRACED was on when they were posted. 1206 */ 1207 if (mask & pr->ps_sigacts->ps_sigignore && 1208 (pr->ps_flags & PS_TRACED) == 0) 1209 continue; 1210 1211 /* 1212 * If traced, always stop, and stay stopped until released 1213 * by the debugger. If our parent process is waiting for 1214 * us, don't hang as we could deadlock. 1215 */ 1216 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1217 signum != SIGKILL) { 1218 p->p_xstat = signum; 1219 1220 if (dolock) 1221 KERNEL_LOCK(); 1222 single_thread_set(p, SINGLE_PTRACE, 0); 1223 if (dolock) 1224 KERNEL_UNLOCK(); 1225 1226 if (dolock) 1227 SCHED_LOCK(s); 1228 proc_stop(p, 1); 1229 if (dolock) 1230 SCHED_UNLOCK(s); 1231 1232 if (dolock) 1233 KERNEL_LOCK(); 1234 single_thread_clear(p, 0); 1235 if (dolock) 1236 KERNEL_UNLOCK(); 1237 1238 /* 1239 * If we are no longer being traced, or the parent 1240 * didn't give us a signal, look for more signals. 1241 */ 1242 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1243 continue; 1244 1245 /* 1246 * If the new signal is being masked, look for other 1247 * signals. 1248 */ 1249 signum = p->p_xstat; 1250 mask = sigmask(signum); 1251 if ((p->p_sigmask & mask) != 0) 1252 continue; 1253 1254 /* take the signal! */ 1255 atomic_clearbits_int(&p->p_siglist, mask); 1256 } 1257 1258 prop = sigprop[signum]; 1259 1260 /* 1261 * Decide whether the signal should be returned. 1262 * Return the signal's number, or fall through 1263 * to clear it from the pending mask. 1264 */ 1265 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1266 case (long)SIG_DFL: 1267 /* 1268 * Don't take default actions on system processes. 1269 */ 1270 if (pr->ps_pid <= 1) { 1271 #ifdef DIAGNOSTIC 1272 /* 1273 * Are you sure you want to ignore SIGSEGV 1274 * in init? XXX 1275 */ 1276 printf("Process (pid %d) got signal" 1277 " %d\n", pr->ps_pid, signum); 1278 #endif 1279 break; /* == ignore */ 1280 } 1281 /* 1282 * If there is a pending stop signal to process 1283 * with default action, stop here, 1284 * then clear the signal. However, 1285 * if process is member of an orphaned 1286 * process group, ignore tty stop signals. 1287 */ 1288 if (prop & SA_STOP) { 1289 if (pr->ps_flags & PS_TRACED || 1290 (pr->ps_pgrp->pg_jobc == 0 && 1291 prop & SA_TTYSTOP)) 1292 break; /* == ignore */ 1293 p->p_xstat = signum; 1294 if (dolock) 1295 SCHED_LOCK(s); 1296 proc_stop(p, 1); 1297 if (dolock) 1298 SCHED_UNLOCK(s); 1299 break; 1300 } else if (prop & SA_IGNORE) { 1301 /* 1302 * Except for SIGCONT, shouldn't get here. 1303 * Default action is to ignore; drop it. 1304 */ 1305 break; /* == ignore */ 1306 } else 1307 goto keep; 1308 /*NOTREACHED*/ 1309 case (long)SIG_IGN: 1310 /* 1311 * Masking above should prevent us ever trying 1312 * to take action on an ignored signal other 1313 * than SIGCONT, unless process is traced. 1314 */ 1315 if ((prop & SA_CONT) == 0 && 1316 (pr->ps_flags & PS_TRACED) == 0) 1317 printf("issignal\n"); 1318 break; /* == ignore */ 1319 default: 1320 /* 1321 * This signal has an action, let 1322 * postsig() process it. 1323 */ 1324 goto keep; 1325 } 1326 } 1327 /* NOTREACHED */ 1328 1329 keep: 1330 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1331 return (signum); 1332 } 1333 1334 /* 1335 * Put the argument process into the stopped state and notify the parent 1336 * via wakeup. Signals are handled elsewhere. The process must not be 1337 * on the run queue. 1338 */ 1339 void 1340 proc_stop(struct proc *p, int sw) 1341 { 1342 struct process *pr = p->p_p; 1343 extern void *softclock_si; 1344 1345 #ifdef MULTIPROCESSOR 1346 SCHED_ASSERT_LOCKED(); 1347 #endif 1348 1349 p->p_stat = SSTOP; 1350 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1351 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1352 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1353 if (!timeout_pending(&proc_stop_to)) { 1354 timeout_add(&proc_stop_to, 0); 1355 /* 1356 * We need this soft interrupt to be handled fast. 1357 * Extra calls to softclock don't hurt. 1358 */ 1359 softintr_schedule(softclock_si); 1360 } 1361 if (sw) 1362 mi_switch(); 1363 } 1364 1365 /* 1366 * Called from a timeout to send signals to the parents of stopped processes. 1367 * We can't do this in proc_stop because it's called with nasty locks held 1368 * and we would need recursive scheduler lock to deal with that. 1369 */ 1370 void 1371 proc_stop_sweep(void *v) 1372 { 1373 struct process *pr; 1374 1375 LIST_FOREACH(pr, &allprocess, ps_list) { 1376 if ((pr->ps_flags & PS_STOPPED) == 0) 1377 continue; 1378 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1379 1380 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1381 prsignal(pr->ps_pptr, SIGCHLD); 1382 wakeup(pr->ps_pptr); 1383 } 1384 } 1385 1386 /* 1387 * Take the action for the specified signal 1388 * from the current set of pending signals. 1389 */ 1390 void 1391 postsig(struct proc *p, int signum) 1392 { 1393 struct process *pr = p->p_p; 1394 struct sigacts *ps = pr->ps_sigacts; 1395 sig_t action; 1396 u_long trapno; 1397 int mask, returnmask; 1398 siginfo_t si; 1399 union sigval sigval; 1400 int s, code; 1401 1402 KASSERT(signum != 0); 1403 KERNEL_ASSERT_LOCKED(); 1404 1405 mask = sigmask(signum); 1406 atomic_clearbits_int(&p->p_siglist, mask); 1407 action = ps->ps_sigact[signum]; 1408 sigval.sival_ptr = 0; 1409 1410 if (p->p_sisig != signum) { 1411 trapno = 0; 1412 code = SI_USER; 1413 sigval.sival_ptr = 0; 1414 } else { 1415 trapno = p->p_sitrapno; 1416 code = p->p_sicode; 1417 sigval = p->p_sigval; 1418 } 1419 initsiginfo(&si, signum, trapno, code, sigval); 1420 1421 #ifdef KTRACE 1422 if (KTRPOINT(p, KTR_PSIG)) { 1423 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1424 p->p_oldmask : p->p_sigmask, code, &si); 1425 } 1426 #endif 1427 if (action == SIG_DFL) { 1428 /* 1429 * Default action, where the default is to kill 1430 * the process. (Other cases were ignored above.) 1431 */ 1432 sigexit(p, signum); 1433 /* NOTREACHED */ 1434 } else { 1435 /* 1436 * If we get here, the signal must be caught. 1437 */ 1438 #ifdef DIAGNOSTIC 1439 if (action == SIG_IGN || (p->p_sigmask & mask)) 1440 panic("postsig action"); 1441 #endif 1442 /* 1443 * Set the new mask value and also defer further 1444 * occurrences of this signal. 1445 * 1446 * Special case: user has done a sigpause. Here the 1447 * current mask is not of interest, but rather the 1448 * mask from before the sigpause is what we want 1449 * restored after the signal processing is completed. 1450 */ 1451 #ifdef MULTIPROCESSOR 1452 s = splsched(); 1453 #else 1454 s = splhigh(); 1455 #endif 1456 if (p->p_flag & P_SIGSUSPEND) { 1457 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1458 returnmask = p->p_oldmask; 1459 } else { 1460 returnmask = p->p_sigmask; 1461 } 1462 if (p->p_sisig == signum) { 1463 p->p_sisig = 0; 1464 p->p_sitrapno = 0; 1465 p->p_sicode = SI_USER; 1466 p->p_sigval.sival_ptr = NULL; 1467 } 1468 1469 sendsig(action, signum, returnmask, &si); 1470 postsig_done(p, signum, ps); 1471 splx(s); 1472 } 1473 } 1474 1475 /* 1476 * Force the current process to exit with the specified signal, dumping core 1477 * if appropriate. We bypass the normal tests for masked and caught signals, 1478 * allowing unrecoverable failures to terminate the process without changing 1479 * signal state. Mark the accounting record with the signal termination. 1480 * If dumping core, save the signal number for the debugger. Calls exit and 1481 * does not return. 1482 */ 1483 void 1484 sigexit(struct proc *p, int signum) 1485 { 1486 /* Mark process as going away */ 1487 atomic_setbits_int(&p->p_flag, P_WEXIT); 1488 1489 p->p_p->ps_acflag |= AXSIG; 1490 if (sigprop[signum] & SA_CORE) { 1491 p->p_sisig = signum; 1492 1493 /* if there are other threads, pause them */ 1494 if (P_HASSIBLING(p)) 1495 single_thread_set(p, SINGLE_SUSPEND, 0); 1496 1497 if (coredump(p) == 0) 1498 signum |= WCOREFLAG; 1499 } 1500 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1501 /* NOTREACHED */ 1502 } 1503 1504 int nosuidcoredump = 1; 1505 1506 struct coredump_iostate { 1507 struct proc *io_proc; 1508 struct vnode *io_vp; 1509 struct ucred *io_cred; 1510 off_t io_offset; 1511 }; 1512 1513 /* 1514 * Dump core, into a file named "progname.core", unless the process was 1515 * setuid/setgid. 1516 */ 1517 int 1518 coredump(struct proc *p) 1519 { 1520 #ifdef SMALL_KERNEL 1521 return EPERM; 1522 #else 1523 struct process *pr = p->p_p; 1524 struct vnode *vp; 1525 struct ucred *cred = p->p_ucred; 1526 struct vmspace *vm = p->p_vmspace; 1527 struct nameidata nd; 1528 struct vattr vattr; 1529 struct coredump_iostate io; 1530 int error, len, incrash = 0; 1531 char name[MAXPATHLEN]; 1532 const char *dir = "/var/crash"; 1533 1534 if (pr->ps_emul->e_coredump == NULL) 1535 return (EINVAL); 1536 1537 pr->ps_flags |= PS_COREDUMP; 1538 1539 /* 1540 * If the process has inconsistent uids, nosuidcoredump 1541 * determines coredump placement policy. 1542 */ 1543 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1544 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1545 if (nosuidcoredump == 3 || nosuidcoredump == 2) 1546 incrash = 1; 1547 else 1548 return (EPERM); 1549 } 1550 1551 /* Don't dump if will exceed file size limit. */ 1552 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= 1553 p->p_rlimit[RLIMIT_CORE].rlim_cur) 1554 return (EFBIG); 1555 1556 if (incrash && nosuidcoredump == 3) { 1557 /* 1558 * If the program directory does not exist, dumps of 1559 * that core will silently fail. 1560 */ 1561 len = snprintf(name, sizeof(name), "%s/%s/%u.core", 1562 dir, pr->ps_comm, pr->ps_pid); 1563 } else if (incrash && nosuidcoredump == 2) 1564 len = snprintf(name, sizeof(name), "%s/%s.core", 1565 dir, pr->ps_comm); 1566 else 1567 len = snprintf(name, sizeof(name), "%s.core", pr->ps_comm); 1568 if (len >= sizeof(name)) 1569 return (EACCES); 1570 1571 /* 1572 * Control the UID used to write out. The normal case uses 1573 * the real UID. If the sugid case is going to write into the 1574 * controlled directory, we do so as root. 1575 */ 1576 if (incrash == 0) { 1577 cred = crdup(cred); 1578 cred->cr_uid = cred->cr_ruid; 1579 cred->cr_gid = cred->cr_rgid; 1580 } else { 1581 if (p->p_fd->fd_rdir) { 1582 vrele(p->p_fd->fd_rdir); 1583 p->p_fd->fd_rdir = NULL; 1584 } 1585 p->p_ucred = crdup(p->p_ucred); 1586 crfree(cred); 1587 cred = p->p_ucred; 1588 crhold(cred); 1589 cred->cr_uid = 0; 1590 cred->cr_gid = 0; 1591 } 1592 1593 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1594 1595 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1596 1597 if (error) 1598 goto out; 1599 1600 /* 1601 * Don't dump to non-regular files, files with links, or files 1602 * owned by someone else. 1603 */ 1604 vp = nd.ni_vp; 1605 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1606 VOP_UNLOCK(vp); 1607 vn_close(vp, FWRITE, cred, p); 1608 goto out; 1609 } 1610 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1611 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1612 vattr.va_uid != cred->cr_uid) { 1613 error = EACCES; 1614 VOP_UNLOCK(vp); 1615 vn_close(vp, FWRITE, cred, p); 1616 goto out; 1617 } 1618 VATTR_NULL(&vattr); 1619 vattr.va_size = 0; 1620 VOP_SETATTR(vp, &vattr, cred, p); 1621 pr->ps_acflag |= ACORE; 1622 1623 io.io_proc = p; 1624 io.io_vp = vp; 1625 io.io_cred = cred; 1626 io.io_offset = 0; 1627 VOP_UNLOCK(vp); 1628 vref(vp); 1629 error = vn_close(vp, FWRITE, cred, p); 1630 if (error == 0) 1631 error = (*pr->ps_emul->e_coredump)(p, &io); 1632 vrele(vp); 1633 out: 1634 crfree(cred); 1635 return (error); 1636 #endif 1637 } 1638 1639 #ifndef SMALL_KERNEL 1640 int 1641 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1642 { 1643 struct coredump_iostate *io = cookie; 1644 off_t coffset = 0; 1645 size_t csize; 1646 int chunk, error; 1647 1648 csize = len; 1649 do { 1650 if (io->io_proc->p_siglist & sigmask(SIGKILL)) 1651 return (EINTR); 1652 1653 /* Rest of the loop sleeps with lock held, so... */ 1654 yield(); 1655 1656 chunk = MIN(csize, MAXPHYS); 1657 error = vn_rdwr(UIO_WRITE, io->io_vp, 1658 (caddr_t)data + coffset, chunk, 1659 io->io_offset + coffset, segflg, 1660 IO_UNIT, io->io_cred, NULL, io->io_proc); 1661 if (error) { 1662 struct process *pr = io->io_proc->p_p; 1663 1664 if (error == ENOSPC) 1665 log(LOG_ERR, 1666 "coredump of %s(%d) failed, filesystem full\n", 1667 pr->ps_comm, pr->ps_pid); 1668 else 1669 log(LOG_ERR, 1670 "coredump of %s(%d), write failed: errno %d\n", 1671 pr->ps_comm, pr->ps_pid, error); 1672 return (error); 1673 } 1674 1675 coffset += chunk; 1676 csize -= chunk; 1677 } while (csize > 0); 1678 1679 io->io_offset += len; 1680 return (0); 1681 } 1682 1683 void 1684 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1685 { 1686 struct coredump_iostate *io = cookie; 1687 1688 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1689 } 1690 1691 #endif /* !SMALL_KERNEL */ 1692 1693 /* 1694 * Nonexistent system call-- signal process (may want to handle it). 1695 * Flag error in case process won't see signal immediately (blocked or ignored). 1696 */ 1697 int 1698 sys_nosys(struct proc *p, void *v, register_t *retval) 1699 { 1700 1701 ptsignal(p, SIGSYS, STHREAD); 1702 return (ENOSYS); 1703 } 1704 1705 int 1706 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1707 { 1708 static int sigwaitsleep; 1709 struct sys___thrsigdivert_args /* { 1710 syscallarg(sigset_t) sigmask; 1711 syscallarg(siginfo_t *) info; 1712 syscallarg(const struct timespec *) timeout; 1713 } */ *uap = v; 1714 struct process *pr = p->p_p; 1715 sigset_t *m; 1716 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1717 siginfo_t si; 1718 uint64_t to_ticks = 0; 1719 int timeinvalid = 0; 1720 int error = 0; 1721 1722 memset(&si, 0, sizeof(si)); 1723 1724 if (SCARG(uap, timeout) != NULL) { 1725 struct timespec ts; 1726 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1727 return (error); 1728 #ifdef KTRACE 1729 if (KTRPOINT(p, KTR_STRUCT)) 1730 ktrreltimespec(p, &ts); 1731 #endif 1732 if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000) 1733 timeinvalid = 1; 1734 else { 1735 to_ticks = (uint64_t)hz * ts.tv_sec + 1736 ts.tv_nsec / (tick * 1000); 1737 if (to_ticks > INT_MAX) 1738 to_ticks = INT_MAX; 1739 if (to_ticks == 0 && ts.tv_nsec) 1740 to_ticks = 1; 1741 } 1742 } 1743 1744 dosigsuspend(p, p->p_sigmask &~ mask); 1745 for (;;) { 1746 si.si_signo = CURSIG(p); 1747 if (si.si_signo != 0) { 1748 sigset_t smask = sigmask(si.si_signo); 1749 if (smask & mask) { 1750 if (p->p_siglist & smask) 1751 m = &p->p_siglist; 1752 else if (pr->ps_mainproc->p_siglist & smask) 1753 m = &pr->ps_mainproc->p_siglist; 1754 else { 1755 /* signal got eaten by someone else? */ 1756 continue; 1757 } 1758 atomic_clearbits_int(m, smask); 1759 error = 0; 1760 break; 1761 } 1762 } 1763 1764 /* per-POSIX, delay this error until after the above */ 1765 if (timeinvalid) 1766 error = EINVAL; 1767 1768 if (SCARG(uap, timeout) != NULL && to_ticks == 0) 1769 error = EAGAIN; 1770 1771 if (error != 0) 1772 break; 1773 1774 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1775 (int)to_ticks); 1776 } 1777 1778 if (error == 0) { 1779 *retval = si.si_signo; 1780 if (SCARG(uap, info) != NULL) 1781 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1782 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1783 /* 1784 * Restarting is wrong if there's a timeout, as it'll be 1785 * for the same interval again 1786 */ 1787 error = EINTR; 1788 } 1789 1790 return (error); 1791 } 1792 1793 void 1794 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1795 { 1796 memset(si, 0, sizeof(*si)); 1797 1798 si->si_signo = sig; 1799 si->si_code = code; 1800 if (code == SI_USER) { 1801 si->si_value = val; 1802 } else { 1803 switch (sig) { 1804 case SIGSEGV: 1805 case SIGILL: 1806 case SIGBUS: 1807 case SIGFPE: 1808 si->si_addr = val.sival_ptr; 1809 si->si_trapno = trapno; 1810 break; 1811 case SIGXFSZ: 1812 break; 1813 } 1814 } 1815 } 1816 1817 int 1818 filt_sigattach(struct knote *kn) 1819 { 1820 struct process *pr = curproc->p_p; 1821 1822 if (kn->kn_id >= NSIG) 1823 return EINVAL; 1824 1825 kn->kn_ptr.p_process = pr; 1826 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1827 1828 /* XXX lock the proc here while adding to the list? */ 1829 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1830 1831 return (0); 1832 } 1833 1834 void 1835 filt_sigdetach(struct knote *kn) 1836 { 1837 struct process *pr = kn->kn_ptr.p_process; 1838 1839 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1840 } 1841 1842 /* 1843 * signal knotes are shared with proc knotes, so we apply a mask to 1844 * the hint in order to differentiate them from process hints. This 1845 * could be avoided by using a signal-specific knote list, but probably 1846 * isn't worth the trouble. 1847 */ 1848 int 1849 filt_signal(struct knote *kn, long hint) 1850 { 1851 1852 if (hint & NOTE_SIGNAL) { 1853 hint &= ~NOTE_SIGNAL; 1854 1855 if (kn->kn_id == hint) 1856 kn->kn_data++; 1857 } 1858 return (kn->kn_data != 0); 1859 } 1860 1861 void 1862 userret(struct proc *p) 1863 { 1864 int signum; 1865 1866 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1867 if (p->p_flag & P_PROFPEND) { 1868 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1869 KERNEL_LOCK(); 1870 psignal(p, SIGPROF); 1871 KERNEL_UNLOCK(); 1872 } 1873 if (p->p_flag & P_ALRMPEND) { 1874 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1875 KERNEL_LOCK(); 1876 psignal(p, SIGVTALRM); 1877 KERNEL_UNLOCK(); 1878 } 1879 1880 if (SIGPENDING(p)) { 1881 KERNEL_LOCK(); 1882 while ((signum = CURSIG(p)) != 0) 1883 postsig(p, signum); 1884 KERNEL_UNLOCK(); 1885 } 1886 1887 /* 1888 * If P_SIGSUSPEND is still set here, then we still need to restore 1889 * the original sigmask before returning to userspace. Also, this 1890 * might unmask some pending signals, so we need to check a second 1891 * time for signals to post. 1892 */ 1893 if (p->p_flag & P_SIGSUSPEND) { 1894 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1895 p->p_sigmask = p->p_oldmask; 1896 1897 KERNEL_LOCK(); 1898 while ((signum = CURSIG(p)) != 0) 1899 postsig(p, signum); 1900 KERNEL_UNLOCK(); 1901 } 1902 1903 if (p->p_flag & P_SUSPSINGLE) { 1904 KERNEL_LOCK(); 1905 single_thread_check(p, 0); 1906 KERNEL_UNLOCK(); 1907 } 1908 1909 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1910 1911 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1912 } 1913 1914 int 1915 single_thread_check(struct proc *p, int deep) 1916 { 1917 struct process *pr = p->p_p; 1918 1919 if (pr->ps_single != NULL && pr->ps_single != p) { 1920 do { 1921 int s; 1922 1923 /* if we're in deep, we need to unwind to the edge */ 1924 if (deep) { 1925 if (pr->ps_flags & PS_SINGLEUNWIND) 1926 return (ERESTART); 1927 if (pr->ps_flags & PS_SINGLEEXIT) 1928 return (EINTR); 1929 } 1930 1931 if (--pr->ps_singlecount == 0) 1932 wakeup(&pr->ps_singlecount); 1933 if (pr->ps_flags & PS_SINGLEEXIT) 1934 exit1(p, 0, EXIT_THREAD_NOCHECK); 1935 1936 /* not exiting and don't need to unwind, so suspend */ 1937 SCHED_LOCK(s); 1938 p->p_stat = SSTOP; 1939 mi_switch(); 1940 SCHED_UNLOCK(s); 1941 } while (pr->ps_single != NULL); 1942 } 1943 1944 return (0); 1945 } 1946 1947 /* 1948 * Stop other threads in the process. The mode controls how and 1949 * where the other threads should stop: 1950 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1951 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1952 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1953 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1954 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1955 * or released as with SINGLE_SUSPEND 1956 * - SINGLE_EXIT: unwind to kernel boundary and exit 1957 */ 1958 int 1959 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1960 { 1961 struct process *pr = p->p_p; 1962 struct proc *q; 1963 int error; 1964 1965 KERNEL_ASSERT_LOCKED(); 1966 1967 if ((error = single_thread_check(p, deep))) 1968 return error; 1969 1970 switch (mode) { 1971 case SINGLE_SUSPEND: 1972 case SINGLE_PTRACE: 1973 break; 1974 case SINGLE_UNWIND: 1975 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1976 break; 1977 case SINGLE_EXIT: 1978 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1979 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1980 break; 1981 #ifdef DIAGNOSTIC 1982 default: 1983 panic("single_thread_mode = %d", mode); 1984 #endif 1985 } 1986 pr->ps_single = p; 1987 pr->ps_singlecount = 0; 1988 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1989 int s; 1990 1991 if (q == p) 1992 continue; 1993 if (q->p_flag & P_WEXIT) { 1994 if (mode == SINGLE_EXIT) { 1995 SCHED_LOCK(s); 1996 if (q->p_stat == SSTOP) { 1997 setrunnable(q); 1998 pr->ps_singlecount++; 1999 } 2000 SCHED_UNLOCK(s); 2001 } 2002 continue; 2003 } 2004 SCHED_LOCK(s); 2005 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2006 switch (q->p_stat) { 2007 case SIDL: 2008 case SRUN: 2009 pr->ps_singlecount++; 2010 break; 2011 case SSLEEP: 2012 /* if it's not interruptible, then just have to wait */ 2013 if (q->p_flag & P_SINTR) { 2014 /* merely need to suspend? just stop it */ 2015 if (mode == SINGLE_SUSPEND || 2016 mode == SINGLE_PTRACE) { 2017 q->p_stat = SSTOP; 2018 break; 2019 } 2020 /* need to unwind or exit, so wake it */ 2021 setrunnable(q); 2022 } 2023 pr->ps_singlecount++; 2024 break; 2025 case SSTOP: 2026 if (mode == SINGLE_EXIT) { 2027 setrunnable(q); 2028 pr->ps_singlecount++; 2029 } 2030 break; 2031 case SDEAD: 2032 break; 2033 case SONPROC: 2034 pr->ps_singlecount++; 2035 signotify(q); 2036 break; 2037 } 2038 SCHED_UNLOCK(s); 2039 } 2040 2041 if (mode != SINGLE_PTRACE) 2042 single_thread_wait(pr); 2043 2044 return 0; 2045 } 2046 2047 void 2048 single_thread_wait(struct process *pr) 2049 { 2050 /* wait until they're all suspended */ 2051 while (pr->ps_singlecount > 0) 2052 tsleep(&pr->ps_singlecount, PUSER, "suspend", 0); 2053 } 2054 2055 void 2056 single_thread_clear(struct proc *p, int flag) 2057 { 2058 struct process *pr = p->p_p; 2059 struct proc *q; 2060 2061 KASSERT(pr->ps_single == p); 2062 KERNEL_ASSERT_LOCKED(); 2063 2064 pr->ps_single = NULL; 2065 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2066 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2067 int s; 2068 2069 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2070 continue; 2071 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2072 2073 /* 2074 * if the thread was only stopped for single threading 2075 * then clearing that either makes it runnable or puts 2076 * it back into some sleep queue 2077 */ 2078 SCHED_LOCK(s); 2079 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2080 if (q->p_wchan == 0) 2081 setrunnable(q); 2082 else 2083 q->p_stat = SSLEEP; 2084 } 2085 SCHED_UNLOCK(s); 2086 } 2087 } 2088 2089 void 2090 sigio_del(struct sigiolst *rmlist) 2091 { 2092 struct sigio *sigio; 2093 2094 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2095 LIST_REMOVE(sigio, sio_pgsigio); 2096 crfree(sigio->sio_ucred); 2097 free(sigio, M_SIGIO, sizeof(*sigio)); 2098 } 2099 } 2100 2101 void 2102 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2103 { 2104 struct sigio *sigio; 2105 2106 MUTEX_ASSERT_LOCKED(&sigio_lock); 2107 2108 sigio = sir->sir_sigio; 2109 if (sigio != NULL) { 2110 KASSERT(sigio->sio_myref == sir); 2111 sir->sir_sigio = NULL; 2112 2113 if (sigio->sio_pgid > 0) 2114 sigio->sio_proc = NULL; 2115 else 2116 sigio->sio_pgrp = NULL; 2117 LIST_REMOVE(sigio, sio_pgsigio); 2118 2119 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2120 } 2121 } 2122 2123 void 2124 sigio_free(struct sigio_ref *sir) 2125 { 2126 struct sigiolst rmlist; 2127 2128 if (sir->sir_sigio == NULL) 2129 return; 2130 2131 LIST_INIT(&rmlist); 2132 2133 mtx_enter(&sigio_lock); 2134 sigio_unlink(sir, &rmlist); 2135 mtx_leave(&sigio_lock); 2136 2137 sigio_del(&rmlist); 2138 } 2139 2140 void 2141 sigio_freelist(struct sigiolst *sigiolst) 2142 { 2143 struct sigiolst rmlist; 2144 struct sigio *sigio; 2145 2146 if (LIST_EMPTY(sigiolst)) 2147 return; 2148 2149 LIST_INIT(&rmlist); 2150 2151 mtx_enter(&sigio_lock); 2152 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2153 sigio_unlink(sigio->sio_myref, &rmlist); 2154 mtx_leave(&sigio_lock); 2155 2156 sigio_del(&rmlist); 2157 } 2158 2159 int 2160 sigio_setown(struct sigio_ref *sir, pid_t pgid) 2161 { 2162 struct sigiolst rmlist; 2163 struct proc *p = curproc; 2164 struct pgrp *pgrp = NULL; 2165 struct process *pr = NULL; 2166 struct sigio *sigio; 2167 int error; 2168 2169 if (pgid == 0) { 2170 sigio_free(sir); 2171 return (0); 2172 } 2173 2174 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2175 sigio->sio_pgid = pgid; 2176 sigio->sio_ucred = crhold(p->p_ucred); 2177 sigio->sio_myref = sir; 2178 2179 LIST_INIT(&rmlist); 2180 2181 /* 2182 * The kernel lock, and not sleeping between prfind()/pgfind() and 2183 * linking of the sigio ensure that the process or process group does 2184 * not disappear unexpectedly. 2185 */ 2186 KERNEL_LOCK(); 2187 mtx_enter(&sigio_lock); 2188 2189 if (pgid > 0) { 2190 pr = prfind(pgid); 2191 if (pr == NULL) { 2192 error = ESRCH; 2193 goto fail; 2194 } 2195 2196 /* 2197 * Policy - Don't allow a process to FSETOWN a process 2198 * in another session. 2199 * 2200 * Remove this test to allow maximum flexibility or 2201 * restrict FSETOWN to the current process or process 2202 * group for maximum safety. 2203 */ 2204 if (pr->ps_session != p->p_p->ps_session) { 2205 error = EPERM; 2206 goto fail; 2207 } 2208 2209 if ((pr->ps_flags & PS_EXITING) != 0) { 2210 error = ESRCH; 2211 goto fail; 2212 } 2213 } else /* if (pgid < 0) */ { 2214 pgrp = pgfind(-pgid); 2215 if (pgrp == NULL) { 2216 error = ESRCH; 2217 goto fail; 2218 } 2219 2220 /* 2221 * Policy - Don't allow a process to FSETOWN a process 2222 * in another session. 2223 * 2224 * Remove this test to allow maximum flexibility or 2225 * restrict FSETOWN to the current process or process 2226 * group for maximum safety. 2227 */ 2228 if (pgrp->pg_session != p->p_p->ps_session) { 2229 error = EPERM; 2230 goto fail; 2231 } 2232 } 2233 2234 if (pgid > 0) { 2235 sigio->sio_proc = pr; 2236 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2237 } else { 2238 sigio->sio_pgrp = pgrp; 2239 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2240 } 2241 2242 sigio_unlink(sir, &rmlist); 2243 sir->sir_sigio = sigio; 2244 2245 mtx_leave(&sigio_lock); 2246 KERNEL_UNLOCK(); 2247 2248 sigio_del(&rmlist); 2249 2250 return (0); 2251 2252 fail: 2253 mtx_leave(&sigio_lock); 2254 KERNEL_UNLOCK(); 2255 2256 crfree(sigio->sio_ucred); 2257 free(sigio, M_SIGIO, sizeof(*sigio)); 2258 2259 return (error); 2260 } 2261 2262 pid_t 2263 sigio_getown(struct sigio_ref *sir) 2264 { 2265 struct sigio *sigio; 2266 pid_t pgid = 0; 2267 2268 mtx_enter(&sigio_lock); 2269 sigio = sir->sir_sigio; 2270 if (sigio != NULL) 2271 pgid = sigio->sio_pgid; 2272 mtx_leave(&sigio_lock); 2273 2274 return (pgid); 2275 } 2276 2277 void 2278 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2279 { 2280 struct sigiolst rmlist; 2281 struct sigio *newsigio, *sigio; 2282 2283 sigio_free(dst); 2284 2285 if (src->sir_sigio == NULL) 2286 return; 2287 2288 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2289 LIST_INIT(&rmlist); 2290 2291 mtx_enter(&sigio_lock); 2292 2293 sigio = src->sir_sigio; 2294 if (sigio == NULL) { 2295 mtx_leave(&sigio_lock); 2296 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2297 return; 2298 } 2299 2300 newsigio->sio_pgid = sigio->sio_pgid; 2301 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2302 newsigio->sio_myref = dst; 2303 if (newsigio->sio_pgid > 0) { 2304 newsigio->sio_proc = sigio->sio_proc; 2305 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2306 sio_pgsigio); 2307 } else { 2308 newsigio->sio_pgrp = sigio->sio_pgrp; 2309 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2310 sio_pgsigio); 2311 } 2312 2313 sigio_unlink(dst, &rmlist); 2314 dst->sir_sigio = newsigio; 2315 2316 mtx_leave(&sigio_lock); 2317 2318 sigio_del(&rmlist); 2319 } 2320