1 /* $OpenBSD: kern_sig.c,v 1.229 2019/05/01 06:26:42 dlg 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. If checktty is 1, 737 * limit to members which have a controlling terminal. 738 */ 739 void 740 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 741 { 742 struct process *pr; 743 744 if (pgrp) 745 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 746 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 747 prsignal(pr, signum); 748 } 749 750 /* 751 * Send a SIGIO or SIGURG signal to a process or process group using stored 752 * credentials rather than those of the current process. 753 */ 754 void 755 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 756 { 757 struct process *pr; 758 struct sigio *sigio; 759 760 if (sir->sir_sigio == NULL) 761 return; 762 763 mtx_enter(&sigio_lock); 764 sigio = sir->sir_sigio; 765 if (sigio == NULL) 766 goto out; 767 if (sigio->sio_pgid > 0) { 768 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 769 prsignal(sigio->sio_proc, sig); 770 } else if (sigio->sio_pgid < 0) { 771 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 772 if (CANSIGIO(sigio->sio_ucred, pr) && 773 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 774 prsignal(pr, sig); 775 } 776 } 777 out: 778 mtx_leave(&sigio_lock); 779 } 780 781 /* 782 * Recalculate the signal mask and reset the signal disposition after 783 * usermode frame for delivery is formed. 784 */ 785 void 786 postsig_done(struct proc *p, int signum, struct sigacts *ps) 787 { 788 int mask = sigmask(signum); 789 790 KERNEL_ASSERT_LOCKED(); 791 792 p->p_ru.ru_nsignals++; 793 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 794 if ((ps->ps_sigreset & mask) != 0) { 795 ps->ps_sigcatch &= ~mask; 796 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 797 ps->ps_sigignore |= mask; 798 ps->ps_sigact[signum] = SIG_DFL; 799 } 800 } 801 802 /* 803 * Send a signal caused by a trap to the current thread 804 * If it will be caught immediately, deliver it with correct code. 805 * Otherwise, post it normally. 806 */ 807 void 808 trapsignal(struct proc *p, int signum, u_long trapno, int code, 809 union sigval sigval) 810 { 811 struct process *pr = p->p_p; 812 struct sigacts *ps = pr->ps_sigacts; 813 int mask; 814 815 switch (signum) { 816 case SIGILL: 817 case SIGBUS: 818 case SIGSEGV: 819 pr->ps_acflag |= ATRAP; 820 break; 821 } 822 823 mask = sigmask(signum); 824 if ((pr->ps_flags & PS_TRACED) == 0 && 825 (ps->ps_sigcatch & mask) != 0 && 826 (p->p_sigmask & mask) == 0) { 827 siginfo_t si; 828 initsiginfo(&si, signum, trapno, code, sigval); 829 #ifdef KTRACE 830 if (KTRPOINT(p, KTR_PSIG)) { 831 ktrpsig(p, signum, ps->ps_sigact[signum], 832 p->p_sigmask, code, &si); 833 } 834 #endif 835 sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si); 836 postsig_done(p, signum, ps); 837 } else { 838 p->p_sisig = signum; 839 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 840 p->p_sicode = code; 841 p->p_sigval = sigval; 842 843 /* 844 * Signals like SIGBUS and SIGSEGV should not, when 845 * generated by the kernel, be ignorable or blockable. 846 * If it is and we're not being traced, then just kill 847 * the process. 848 */ 849 if ((pr->ps_flags & PS_TRACED) == 0 && 850 (sigprop[signum] & SA_KILL) && 851 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 852 sigexit(p, signum); 853 ptsignal(p, signum, STHREAD); 854 } 855 } 856 857 /* 858 * Send the signal to the process. If the signal has an action, the action 859 * is usually performed by the target process rather than the caller; we add 860 * the signal to the set of pending signals for the process. 861 * 862 * Exceptions: 863 * o When a stop signal is sent to a sleeping process that takes the 864 * default action, the process is stopped without awakening it. 865 * o SIGCONT restarts stopped processes (or puts them back to sleep) 866 * regardless of the signal action (eg, blocked or ignored). 867 * 868 * Other ignored signals are discarded immediately. 869 */ 870 void 871 psignal(struct proc *p, int signum) 872 { 873 ptsignal(p, signum, SPROCESS); 874 } 875 876 /* 877 * type = SPROCESS process signal, can be diverted (sigwait()) 878 * XXX if blocked in all threads, mark as pending in struct process 879 * type = STHREAD thread signal, but should be propagated if unhandled 880 * type = SPROPAGATED propagated to this thread, so don't propagate again 881 */ 882 void 883 ptsignal(struct proc *p, int signum, enum signal_type type) 884 { 885 int s, prop; 886 sig_t action; 887 int mask; 888 struct process *pr = p->p_p; 889 struct proc *q; 890 int wakeparent = 0; 891 892 KERNEL_ASSERT_LOCKED(); 893 894 #ifdef DIAGNOSTIC 895 if ((u_int)signum >= NSIG || signum == 0) 896 panic("psignal signal number"); 897 #endif 898 899 /* Ignore signal if the target process is exiting */ 900 if (pr->ps_flags & PS_EXITING) 901 return; 902 903 mask = sigmask(signum); 904 905 if (type == SPROCESS) { 906 /* Accept SIGKILL to coredumping processes */ 907 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 908 if (pr->ps_single != NULL) 909 p = pr->ps_single; 910 atomic_setbits_int(&p->p_siglist, mask); 911 return; 912 } 913 914 /* 915 * If the current thread can process the signal 916 * immediately (it's unblocked) then have it take it. 917 */ 918 q = curproc; 919 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 920 (q->p_sigmask & mask) == 0) 921 p = q; 922 else { 923 /* 924 * A process-wide signal can be diverted to a 925 * different thread that's in sigwait() for this 926 * signal. If there isn't such a thread, then 927 * pick a thread that doesn't have it blocked so 928 * that the stop/kill consideration isn't 929 * delayed. Otherwise, mark it pending on the 930 * main thread. 931 */ 932 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 933 /* ignore exiting threads */ 934 if (q->p_flag & P_WEXIT) 935 continue; 936 937 /* skip threads that have the signal blocked */ 938 if ((q->p_sigmask & mask) != 0) 939 continue; 940 941 /* okay, could send to this thread */ 942 p = q; 943 944 /* 945 * sigsuspend, sigwait, ppoll/pselect, etc? 946 * Definitely go to this thread, as it's 947 * already blocked in the kernel. 948 */ 949 if (q->p_flag & P_SIGSUSPEND) 950 break; 951 } 952 } 953 } 954 955 if (type != SPROPAGATED) 956 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 957 958 prop = sigprop[signum]; 959 960 /* 961 * If proc is traced, always give parent a chance. 962 */ 963 if (pr->ps_flags & PS_TRACED) { 964 action = SIG_DFL; 965 atomic_setbits_int(&p->p_siglist, mask); 966 } else { 967 /* 968 * If the signal is being ignored, 969 * then we forget about it immediately. 970 * (Note: we don't set SIGCONT in ps_sigignore, 971 * and if it is set to SIG_IGN, 972 * action will be SIG_DFL here.) 973 */ 974 if (pr->ps_sigacts->ps_sigignore & mask) 975 return; 976 if (p->p_sigmask & mask) { 977 action = SIG_HOLD; 978 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 979 action = SIG_CATCH; 980 } else { 981 action = SIG_DFL; 982 983 if (prop & SA_KILL && pr->ps_nice > NZERO) 984 pr->ps_nice = NZERO; 985 986 /* 987 * If sending a tty stop signal to a member of an 988 * orphaned process group, discard the signal here if 989 * the action is default; don't stop the process below 990 * if sleeping, and don't clear any pending SIGCONT. 991 */ 992 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 993 return; 994 } 995 996 atomic_setbits_int(&p->p_siglist, mask); 997 } 998 999 if (prop & SA_CONT) 1000 atomic_clearbits_int(&p->p_siglist, stopsigmask); 1001 1002 if (prop & SA_STOP) { 1003 atomic_clearbits_int(&p->p_siglist, contsigmask); 1004 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1005 } 1006 1007 /* 1008 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1009 */ 1010 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1011 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1012 if (q != p) 1013 ptsignal(q, signum, SPROPAGATED); 1014 1015 /* 1016 * Defer further processing for signals which are held, 1017 * except that stopped processes must be continued by SIGCONT. 1018 */ 1019 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 1020 return; 1021 1022 SCHED_LOCK(s); 1023 1024 switch (p->p_stat) { 1025 1026 case SSLEEP: 1027 /* 1028 * If process is sleeping uninterruptibly 1029 * we can't interrupt the sleep... the signal will 1030 * be noticed when the process returns through 1031 * trap() or syscall(). 1032 */ 1033 if ((p->p_flag & P_SINTR) == 0) 1034 goto out; 1035 /* 1036 * Process is sleeping and traced... make it runnable 1037 * so it can discover the signal in issignal() and stop 1038 * for the parent. 1039 */ 1040 if (pr->ps_flags & PS_TRACED) 1041 goto run; 1042 /* 1043 * If SIGCONT is default (or ignored) and process is 1044 * asleep, we are finished; the process should not 1045 * be awakened. 1046 */ 1047 if ((prop & SA_CONT) && action == SIG_DFL) { 1048 atomic_clearbits_int(&p->p_siglist, mask); 1049 goto out; 1050 } 1051 /* 1052 * When a sleeping process receives a stop 1053 * signal, process immediately if possible. 1054 */ 1055 if ((prop & SA_STOP) && action == SIG_DFL) { 1056 /* 1057 * If a child holding parent blocked, 1058 * stopping could cause deadlock. 1059 */ 1060 if (pr->ps_flags & PS_PPWAIT) 1061 goto out; 1062 atomic_clearbits_int(&p->p_siglist, mask); 1063 p->p_xstat = signum; 1064 proc_stop(p, 0); 1065 goto out; 1066 } 1067 /* 1068 * All other (caught or default) signals 1069 * cause the process to run. 1070 */ 1071 goto runfast; 1072 /*NOTREACHED*/ 1073 1074 case SSTOP: 1075 /* 1076 * If traced process is already stopped, 1077 * then no further action is necessary. 1078 */ 1079 if (pr->ps_flags & PS_TRACED) 1080 goto out; 1081 1082 /* 1083 * Kill signal always sets processes running. 1084 */ 1085 if (signum == SIGKILL) { 1086 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1087 goto runfast; 1088 } 1089 1090 if (prop & SA_CONT) { 1091 /* 1092 * If SIGCONT is default (or ignored), we continue the 1093 * process but don't leave the signal in p_siglist, as 1094 * it has no further action. If SIGCONT is held, we 1095 * continue the process and leave the signal in 1096 * p_siglist. If the process catches SIGCONT, let it 1097 * handle the signal itself. If it isn't waiting on 1098 * an event, then it goes back to run state. 1099 * Otherwise, process goes back to sleep state. 1100 */ 1101 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1102 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1103 wakeparent = 1; 1104 if (action == SIG_DFL) 1105 atomic_clearbits_int(&p->p_siglist, mask); 1106 if (action == SIG_CATCH) 1107 goto runfast; 1108 if (p->p_wchan == 0) 1109 goto run; 1110 p->p_stat = SSLEEP; 1111 goto out; 1112 } 1113 1114 if (prop & SA_STOP) { 1115 /* 1116 * Already stopped, don't need to stop again. 1117 * (If we did the shell could get confused.) 1118 */ 1119 atomic_clearbits_int(&p->p_siglist, mask); 1120 goto out; 1121 } 1122 1123 /* 1124 * If process is sleeping interruptibly, then simulate a 1125 * wakeup so that when it is continued, it will be made 1126 * runnable and can look at the signal. But don't make 1127 * the process runnable, leave it stopped. 1128 */ 1129 if (p->p_wchan && p->p_flag & P_SINTR) 1130 unsleep(p); 1131 goto out; 1132 1133 case SONPROC: 1134 signotify(p); 1135 /* FALLTHROUGH */ 1136 default: 1137 /* 1138 * SRUN, SIDL, SDEAD do nothing with the signal, 1139 * other than kicking ourselves if we are running. 1140 * It will either never be noticed, or noticed very soon. 1141 */ 1142 goto out; 1143 } 1144 /*NOTREACHED*/ 1145 1146 runfast: 1147 /* 1148 * Raise priority to at least PUSER. 1149 */ 1150 if (p->p_priority > PUSER) 1151 p->p_priority = PUSER; 1152 run: 1153 setrunnable(p); 1154 out: 1155 SCHED_UNLOCK(s); 1156 if (wakeparent) 1157 wakeup(pr->ps_pptr); 1158 } 1159 1160 /* 1161 * If the current process has received a signal (should be caught or cause 1162 * termination, should interrupt current syscall), return the signal number. 1163 * Stop signals with default action are processed immediately, then cleared; 1164 * they aren't returned. This is checked after each entry to the system for 1165 * a syscall or trap (though this can usually be done without calling issignal 1166 * by checking the pending signal masks in the CURSIG macro.) The normal call 1167 * sequence is 1168 * 1169 * while (signum = CURSIG(curproc)) 1170 * postsig(signum); 1171 * 1172 * Assumes that if the P_SINTR flag is set, we're holding both the 1173 * kernel and scheduler locks. 1174 */ 1175 int 1176 issignal(struct proc *p) 1177 { 1178 struct process *pr = p->p_p; 1179 int signum, mask, prop; 1180 int dolock = (p->p_flag & P_SINTR) == 0; 1181 int s; 1182 1183 for (;;) { 1184 mask = p->p_siglist & ~p->p_sigmask; 1185 if (pr->ps_flags & PS_PPWAIT) 1186 mask &= ~stopsigmask; 1187 if (mask == 0) /* no signal to send */ 1188 return (0); 1189 signum = ffs((long)mask); 1190 mask = sigmask(signum); 1191 atomic_clearbits_int(&p->p_siglist, mask); 1192 1193 /* 1194 * We should see pending but ignored signals 1195 * only if PS_TRACED was on when they were posted. 1196 */ 1197 if (mask & pr->ps_sigacts->ps_sigignore && 1198 (pr->ps_flags & PS_TRACED) == 0) 1199 continue; 1200 1201 /* 1202 * If traced, always stop, and stay stopped until released 1203 * by the debugger. If our parent process is waiting for 1204 * us, don't hang as we could deadlock. 1205 */ 1206 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1207 signum != SIGKILL) { 1208 p->p_xstat = signum; 1209 1210 if (dolock) 1211 KERNEL_LOCK(); 1212 single_thread_set(p, SINGLE_PTRACE, 0); 1213 if (dolock) 1214 KERNEL_UNLOCK(); 1215 1216 if (dolock) 1217 SCHED_LOCK(s); 1218 proc_stop(p, 1); 1219 if (dolock) 1220 SCHED_UNLOCK(s); 1221 1222 if (dolock) 1223 KERNEL_LOCK(); 1224 single_thread_clear(p, 0); 1225 if (dolock) 1226 KERNEL_UNLOCK(); 1227 1228 /* 1229 * If we are no longer being traced, or the parent 1230 * didn't give us a signal, look for more signals. 1231 */ 1232 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1233 continue; 1234 1235 /* 1236 * If the new signal is being masked, look for other 1237 * signals. 1238 */ 1239 signum = p->p_xstat; 1240 mask = sigmask(signum); 1241 if ((p->p_sigmask & mask) != 0) 1242 continue; 1243 1244 /* take the signal! */ 1245 atomic_clearbits_int(&p->p_siglist, mask); 1246 } 1247 1248 prop = sigprop[signum]; 1249 1250 /* 1251 * Decide whether the signal should be returned. 1252 * Return the signal's number, or fall through 1253 * to clear it from the pending mask. 1254 */ 1255 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1256 case (long)SIG_DFL: 1257 /* 1258 * Don't take default actions on system processes. 1259 */ 1260 if (pr->ps_pid <= 1) { 1261 #ifdef DIAGNOSTIC 1262 /* 1263 * Are you sure you want to ignore SIGSEGV 1264 * in init? XXX 1265 */ 1266 printf("Process (pid %d) got signal" 1267 " %d\n", pr->ps_pid, signum); 1268 #endif 1269 break; /* == ignore */ 1270 } 1271 /* 1272 * If there is a pending stop signal to process 1273 * with default action, stop here, 1274 * then clear the signal. However, 1275 * if process is member of an orphaned 1276 * process group, ignore tty stop signals. 1277 */ 1278 if (prop & SA_STOP) { 1279 if (pr->ps_flags & PS_TRACED || 1280 (pr->ps_pgrp->pg_jobc == 0 && 1281 prop & SA_TTYSTOP)) 1282 break; /* == ignore */ 1283 p->p_xstat = signum; 1284 if (dolock) 1285 SCHED_LOCK(s); 1286 proc_stop(p, 1); 1287 if (dolock) 1288 SCHED_UNLOCK(s); 1289 break; 1290 } else if (prop & SA_IGNORE) { 1291 /* 1292 * Except for SIGCONT, shouldn't get here. 1293 * Default action is to ignore; drop it. 1294 */ 1295 break; /* == ignore */ 1296 } else 1297 goto keep; 1298 /*NOTREACHED*/ 1299 case (long)SIG_IGN: 1300 /* 1301 * Masking above should prevent us ever trying 1302 * to take action on an ignored signal other 1303 * than SIGCONT, unless process is traced. 1304 */ 1305 if ((prop & SA_CONT) == 0 && 1306 (pr->ps_flags & PS_TRACED) == 0) 1307 printf("issignal\n"); 1308 break; /* == ignore */ 1309 default: 1310 /* 1311 * This signal has an action, let 1312 * postsig() process it. 1313 */ 1314 goto keep; 1315 } 1316 } 1317 /* NOTREACHED */ 1318 1319 keep: 1320 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1321 return (signum); 1322 } 1323 1324 /* 1325 * Put the argument process into the stopped state and notify the parent 1326 * via wakeup. Signals are handled elsewhere. The process must not be 1327 * on the run queue. 1328 */ 1329 void 1330 proc_stop(struct proc *p, int sw) 1331 { 1332 struct process *pr = p->p_p; 1333 extern void *softclock_si; 1334 1335 #ifdef MULTIPROCESSOR 1336 SCHED_ASSERT_LOCKED(); 1337 #endif 1338 1339 p->p_stat = SSTOP; 1340 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1341 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1342 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1343 if (!timeout_pending(&proc_stop_to)) { 1344 timeout_add(&proc_stop_to, 0); 1345 /* 1346 * We need this soft interrupt to be handled fast. 1347 * Extra calls to softclock don't hurt. 1348 */ 1349 softintr_schedule(softclock_si); 1350 } 1351 if (sw) 1352 mi_switch(); 1353 } 1354 1355 /* 1356 * Called from a timeout to send signals to the parents of stopped processes. 1357 * We can't do this in proc_stop because it's called with nasty locks held 1358 * and we would need recursive scheduler lock to deal with that. 1359 */ 1360 void 1361 proc_stop_sweep(void *v) 1362 { 1363 struct process *pr; 1364 1365 LIST_FOREACH(pr, &allprocess, ps_list) { 1366 if ((pr->ps_flags & PS_STOPPED) == 0) 1367 continue; 1368 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1369 1370 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1371 prsignal(pr->ps_pptr, SIGCHLD); 1372 wakeup(pr->ps_pptr); 1373 } 1374 } 1375 1376 /* 1377 * Take the action for the specified signal 1378 * from the current set of pending signals. 1379 */ 1380 void 1381 postsig(struct proc *p, int signum) 1382 { 1383 struct process *pr = p->p_p; 1384 struct sigacts *ps = pr->ps_sigacts; 1385 sig_t action; 1386 u_long trapno; 1387 int mask, returnmask; 1388 siginfo_t si; 1389 union sigval sigval; 1390 int s, code; 1391 1392 KASSERT(signum != 0); 1393 KERNEL_ASSERT_LOCKED(); 1394 1395 mask = sigmask(signum); 1396 atomic_clearbits_int(&p->p_siglist, mask); 1397 action = ps->ps_sigact[signum]; 1398 sigval.sival_ptr = 0; 1399 1400 if (p->p_sisig != signum) { 1401 trapno = 0; 1402 code = SI_USER; 1403 sigval.sival_ptr = 0; 1404 } else { 1405 trapno = p->p_sitrapno; 1406 code = p->p_sicode; 1407 sigval = p->p_sigval; 1408 } 1409 initsiginfo(&si, signum, trapno, code, sigval); 1410 1411 #ifdef KTRACE 1412 if (KTRPOINT(p, KTR_PSIG)) { 1413 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1414 p->p_oldmask : p->p_sigmask, code, &si); 1415 } 1416 #endif 1417 if (action == SIG_DFL) { 1418 /* 1419 * Default action, where the default is to kill 1420 * the process. (Other cases were ignored above.) 1421 */ 1422 sigexit(p, signum); 1423 /* NOTREACHED */ 1424 } else { 1425 /* 1426 * If we get here, the signal must be caught. 1427 */ 1428 #ifdef DIAGNOSTIC 1429 if (action == SIG_IGN || (p->p_sigmask & mask)) 1430 panic("postsig action"); 1431 #endif 1432 /* 1433 * Set the new mask value and also defer further 1434 * occurrences of this signal. 1435 * 1436 * Special case: user has done a sigpause. Here the 1437 * current mask is not of interest, but rather the 1438 * mask from before the sigpause is what we want 1439 * restored after the signal processing is completed. 1440 */ 1441 #ifdef MULTIPROCESSOR 1442 s = splsched(); 1443 #else 1444 s = splhigh(); 1445 #endif 1446 if (p->p_flag & P_SIGSUSPEND) { 1447 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1448 returnmask = p->p_oldmask; 1449 } else { 1450 returnmask = p->p_sigmask; 1451 } 1452 if (p->p_sisig == signum) { 1453 p->p_sisig = 0; 1454 p->p_sitrapno = 0; 1455 p->p_sicode = SI_USER; 1456 p->p_sigval.sival_ptr = NULL; 1457 } 1458 1459 sendsig(action, signum, returnmask, &si); 1460 postsig_done(p, signum, ps); 1461 splx(s); 1462 } 1463 } 1464 1465 /* 1466 * Force the current process to exit with the specified signal, dumping core 1467 * if appropriate. We bypass the normal tests for masked and caught signals, 1468 * allowing unrecoverable failures to terminate the process without changing 1469 * signal state. Mark the accounting record with the signal termination. 1470 * If dumping core, save the signal number for the debugger. Calls exit and 1471 * does not return. 1472 */ 1473 void 1474 sigexit(struct proc *p, int signum) 1475 { 1476 /* Mark process as going away */ 1477 atomic_setbits_int(&p->p_flag, P_WEXIT); 1478 1479 p->p_p->ps_acflag |= AXSIG; 1480 if (sigprop[signum] & SA_CORE) { 1481 p->p_sisig = signum; 1482 1483 /* if there are other threads, pause them */ 1484 if (P_HASSIBLING(p)) 1485 single_thread_set(p, SINGLE_SUSPEND, 0); 1486 1487 if (coredump(p) == 0) 1488 signum |= WCOREFLAG; 1489 } 1490 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1491 /* NOTREACHED */ 1492 } 1493 1494 int nosuidcoredump = 1; 1495 1496 struct coredump_iostate { 1497 struct proc *io_proc; 1498 struct vnode *io_vp; 1499 struct ucred *io_cred; 1500 off_t io_offset; 1501 }; 1502 1503 /* 1504 * Dump core, into a file named "progname.core", unless the process was 1505 * setuid/setgid. 1506 */ 1507 int 1508 coredump(struct proc *p) 1509 { 1510 #ifdef SMALL_KERNEL 1511 return EPERM; 1512 #else 1513 struct process *pr = p->p_p; 1514 struct vnode *vp; 1515 struct ucred *cred = p->p_ucred; 1516 struct vmspace *vm = p->p_vmspace; 1517 struct nameidata nd; 1518 struct vattr vattr; 1519 struct coredump_iostate io; 1520 int error, len, incrash = 0; 1521 char name[MAXPATHLEN]; 1522 const char *dir = "/var/crash"; 1523 1524 if (pr->ps_emul->e_coredump == NULL) 1525 return (EINVAL); 1526 1527 pr->ps_flags |= PS_COREDUMP; 1528 1529 /* 1530 * If the process has inconsistent uids, nosuidcoredump 1531 * determines coredump placement policy. 1532 */ 1533 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1534 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1535 if (nosuidcoredump == 3 || nosuidcoredump == 2) 1536 incrash = 1; 1537 else 1538 return (EPERM); 1539 } 1540 1541 /* Don't dump if will exceed file size limit. */ 1542 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= 1543 p->p_rlimit[RLIMIT_CORE].rlim_cur) 1544 return (EFBIG); 1545 1546 if (incrash && nosuidcoredump == 3) { 1547 /* 1548 * If the program directory does not exist, dumps of 1549 * that core will silently fail. 1550 */ 1551 len = snprintf(name, sizeof(name), "%s/%s/%u.core", 1552 dir, pr->ps_comm, pr->ps_pid); 1553 } else if (incrash && nosuidcoredump == 2) 1554 len = snprintf(name, sizeof(name), "%s/%s.core", 1555 dir, pr->ps_comm); 1556 else 1557 len = snprintf(name, sizeof(name), "%s.core", pr->ps_comm); 1558 if (len >= sizeof(name)) 1559 return (EACCES); 1560 1561 /* 1562 * Control the UID used to write out. The normal case uses 1563 * the real UID. If the sugid case is going to write into the 1564 * controlled directory, we do so as root. 1565 */ 1566 if (incrash == 0) { 1567 cred = crdup(cred); 1568 cred->cr_uid = cred->cr_ruid; 1569 cred->cr_gid = cred->cr_rgid; 1570 } else { 1571 if (p->p_fd->fd_rdir) { 1572 vrele(p->p_fd->fd_rdir); 1573 p->p_fd->fd_rdir = NULL; 1574 } 1575 p->p_ucred = crdup(p->p_ucred); 1576 crfree(cred); 1577 cred = p->p_ucred; 1578 crhold(cred); 1579 cred->cr_uid = 0; 1580 cred->cr_gid = 0; 1581 } 1582 1583 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1584 1585 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1586 S_IRUSR | S_IWUSR); 1587 1588 if (error) 1589 goto out; 1590 1591 /* 1592 * Don't dump to non-regular files, files with links, or files 1593 * owned by someone else. 1594 */ 1595 vp = nd.ni_vp; 1596 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1597 VOP_UNLOCK(vp); 1598 vn_close(vp, FWRITE, cred, p); 1599 goto out; 1600 } 1601 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1602 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1603 vattr.va_uid != cred->cr_uid) { 1604 error = EACCES; 1605 VOP_UNLOCK(vp); 1606 vn_close(vp, FWRITE, cred, p); 1607 goto out; 1608 } 1609 VATTR_NULL(&vattr); 1610 vattr.va_size = 0; 1611 VOP_SETATTR(vp, &vattr, cred, p); 1612 pr->ps_acflag |= ACORE; 1613 1614 io.io_proc = p; 1615 io.io_vp = vp; 1616 io.io_cred = cred; 1617 io.io_offset = 0; 1618 VOP_UNLOCK(vp); 1619 vref(vp); 1620 error = vn_close(vp, FWRITE, cred, p); 1621 if (error == 0) 1622 error = (*pr->ps_emul->e_coredump)(p, &io); 1623 vrele(vp); 1624 out: 1625 crfree(cred); 1626 return (error); 1627 #endif 1628 } 1629 1630 #ifndef SMALL_KERNEL 1631 int 1632 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1633 { 1634 struct coredump_iostate *io = cookie; 1635 off_t coffset = 0; 1636 size_t csize; 1637 int chunk, error; 1638 1639 csize = len; 1640 do { 1641 if (io->io_proc->p_siglist & sigmask(SIGKILL)) 1642 return (EINTR); 1643 1644 /* Rest of the loop sleeps with lock held, so... */ 1645 yield(); 1646 1647 chunk = MIN(csize, MAXPHYS); 1648 error = vn_rdwr(UIO_WRITE, io->io_vp, 1649 (caddr_t)data + coffset, chunk, 1650 io->io_offset + coffset, segflg, 1651 IO_UNIT, io->io_cred, NULL, io->io_proc); 1652 if (error) { 1653 struct process *pr = io->io_proc->p_p; 1654 1655 if (error == ENOSPC) 1656 log(LOG_ERR, 1657 "coredump of %s(%d) failed, filesystem full\n", 1658 pr->ps_comm, pr->ps_pid); 1659 else 1660 log(LOG_ERR, 1661 "coredump of %s(%d), write failed: errno %d\n", 1662 pr->ps_comm, pr->ps_pid, error); 1663 return (error); 1664 } 1665 1666 coffset += chunk; 1667 csize -= chunk; 1668 } while (csize > 0); 1669 1670 io->io_offset += len; 1671 return (0); 1672 } 1673 1674 void 1675 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1676 { 1677 struct coredump_iostate *io = cookie; 1678 1679 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1680 } 1681 1682 #endif /* !SMALL_KERNEL */ 1683 1684 /* 1685 * Nonexistent system call-- signal process (may want to handle it). 1686 * Flag error in case process won't see signal immediately (blocked or ignored). 1687 */ 1688 int 1689 sys_nosys(struct proc *p, void *v, register_t *retval) 1690 { 1691 1692 ptsignal(p, SIGSYS, STHREAD); 1693 return (ENOSYS); 1694 } 1695 1696 int 1697 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1698 { 1699 static int sigwaitsleep; 1700 struct sys___thrsigdivert_args /* { 1701 syscallarg(sigset_t) sigmask; 1702 syscallarg(siginfo_t *) info; 1703 syscallarg(const struct timespec *) timeout; 1704 } */ *uap = v; 1705 struct process *pr = p->p_p; 1706 sigset_t *m; 1707 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1708 siginfo_t si; 1709 uint64_t to_ticks = 0; 1710 int timeinvalid = 0; 1711 int error = 0; 1712 1713 memset(&si, 0, sizeof(si)); 1714 1715 if (SCARG(uap, timeout) != NULL) { 1716 struct timespec ts; 1717 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1718 return (error); 1719 #ifdef KTRACE 1720 if (KTRPOINT(p, KTR_STRUCT)) 1721 ktrreltimespec(p, &ts); 1722 #endif 1723 if (!timespecisvalid(&ts)) 1724 timeinvalid = 1; 1725 else { 1726 to_ticks = (uint64_t)hz * ts.tv_sec + 1727 ts.tv_nsec / (tick * 1000); 1728 if (to_ticks > INT_MAX) 1729 to_ticks = INT_MAX; 1730 if (to_ticks == 0 && ts.tv_nsec) 1731 to_ticks = 1; 1732 } 1733 } 1734 1735 dosigsuspend(p, p->p_sigmask &~ mask); 1736 for (;;) { 1737 si.si_signo = CURSIG(p); 1738 if (si.si_signo != 0) { 1739 sigset_t smask = sigmask(si.si_signo); 1740 if (smask & mask) { 1741 if (p->p_siglist & smask) 1742 m = &p->p_siglist; 1743 else if (pr->ps_mainproc->p_siglist & smask) 1744 m = &pr->ps_mainproc->p_siglist; 1745 else { 1746 /* signal got eaten by someone else? */ 1747 continue; 1748 } 1749 atomic_clearbits_int(m, smask); 1750 error = 0; 1751 break; 1752 } 1753 } 1754 1755 /* per-POSIX, delay this error until after the above */ 1756 if (timeinvalid) 1757 error = EINVAL; 1758 1759 if (SCARG(uap, timeout) != NULL && to_ticks == 0) 1760 error = EAGAIN; 1761 1762 if (error != 0) 1763 break; 1764 1765 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1766 (int)to_ticks); 1767 } 1768 1769 if (error == 0) { 1770 *retval = si.si_signo; 1771 if (SCARG(uap, info) != NULL) 1772 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1773 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1774 /* 1775 * Restarting is wrong if there's a timeout, as it'll be 1776 * for the same interval again 1777 */ 1778 error = EINTR; 1779 } 1780 1781 return (error); 1782 } 1783 1784 void 1785 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1786 { 1787 memset(si, 0, sizeof(*si)); 1788 1789 si->si_signo = sig; 1790 si->si_code = code; 1791 if (code == SI_USER) { 1792 si->si_value = val; 1793 } else { 1794 switch (sig) { 1795 case SIGSEGV: 1796 case SIGILL: 1797 case SIGBUS: 1798 case SIGFPE: 1799 si->si_addr = val.sival_ptr; 1800 si->si_trapno = trapno; 1801 break; 1802 case SIGXFSZ: 1803 break; 1804 } 1805 } 1806 } 1807 1808 int 1809 filt_sigattach(struct knote *kn) 1810 { 1811 struct process *pr = curproc->p_p; 1812 1813 if (kn->kn_id >= NSIG) 1814 return EINVAL; 1815 1816 kn->kn_ptr.p_process = pr; 1817 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1818 1819 /* XXX lock the proc here while adding to the list? */ 1820 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1821 1822 return (0); 1823 } 1824 1825 void 1826 filt_sigdetach(struct knote *kn) 1827 { 1828 struct process *pr = kn->kn_ptr.p_process; 1829 1830 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1831 } 1832 1833 /* 1834 * signal knotes are shared with proc knotes, so we apply a mask to 1835 * the hint in order to differentiate them from process hints. This 1836 * could be avoided by using a signal-specific knote list, but probably 1837 * isn't worth the trouble. 1838 */ 1839 int 1840 filt_signal(struct knote *kn, long hint) 1841 { 1842 1843 if (hint & NOTE_SIGNAL) { 1844 hint &= ~NOTE_SIGNAL; 1845 1846 if (kn->kn_id == hint) 1847 kn->kn_data++; 1848 } 1849 return (kn->kn_data != 0); 1850 } 1851 1852 void 1853 userret(struct proc *p) 1854 { 1855 int signum; 1856 1857 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1858 if (p->p_flag & P_PROFPEND) { 1859 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1860 KERNEL_LOCK(); 1861 psignal(p, SIGPROF); 1862 KERNEL_UNLOCK(); 1863 } 1864 if (p->p_flag & P_ALRMPEND) { 1865 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1866 KERNEL_LOCK(); 1867 psignal(p, SIGVTALRM); 1868 KERNEL_UNLOCK(); 1869 } 1870 1871 if (SIGPENDING(p)) { 1872 KERNEL_LOCK(); 1873 while ((signum = CURSIG(p)) != 0) 1874 postsig(p, signum); 1875 KERNEL_UNLOCK(); 1876 } 1877 1878 /* 1879 * If P_SIGSUSPEND is still set here, then we still need to restore 1880 * the original sigmask before returning to userspace. Also, this 1881 * might unmask some pending signals, so we need to check a second 1882 * time for signals to post. 1883 */ 1884 if (p->p_flag & P_SIGSUSPEND) { 1885 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1886 p->p_sigmask = p->p_oldmask; 1887 1888 KERNEL_LOCK(); 1889 while ((signum = CURSIG(p)) != 0) 1890 postsig(p, signum); 1891 KERNEL_UNLOCK(); 1892 } 1893 1894 if (p->p_flag & P_SUSPSINGLE) { 1895 KERNEL_LOCK(); 1896 single_thread_check(p, 0); 1897 KERNEL_UNLOCK(); 1898 } 1899 1900 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1901 1902 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1903 } 1904 1905 int 1906 single_thread_check(struct proc *p, int deep) 1907 { 1908 struct process *pr = p->p_p; 1909 1910 if (pr->ps_single != NULL && pr->ps_single != p) { 1911 do { 1912 int s; 1913 1914 /* if we're in deep, we need to unwind to the edge */ 1915 if (deep) { 1916 if (pr->ps_flags & PS_SINGLEUNWIND) 1917 return (ERESTART); 1918 if (pr->ps_flags & PS_SINGLEEXIT) 1919 return (EINTR); 1920 } 1921 1922 if (--pr->ps_singlecount == 0) 1923 wakeup(&pr->ps_singlecount); 1924 if (pr->ps_flags & PS_SINGLEEXIT) 1925 exit1(p, 0, EXIT_THREAD_NOCHECK); 1926 1927 /* not exiting and don't need to unwind, so suspend */ 1928 SCHED_LOCK(s); 1929 p->p_stat = SSTOP; 1930 mi_switch(); 1931 SCHED_UNLOCK(s); 1932 } while (pr->ps_single != NULL); 1933 } 1934 1935 return (0); 1936 } 1937 1938 /* 1939 * Stop other threads in the process. The mode controls how and 1940 * where the other threads should stop: 1941 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1942 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1943 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1944 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1945 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1946 * or released as with SINGLE_SUSPEND 1947 * - SINGLE_EXIT: unwind to kernel boundary and exit 1948 */ 1949 int 1950 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1951 { 1952 struct process *pr = p->p_p; 1953 struct proc *q; 1954 int error; 1955 1956 KERNEL_ASSERT_LOCKED(); 1957 1958 if ((error = single_thread_check(p, deep))) 1959 return error; 1960 1961 switch (mode) { 1962 case SINGLE_SUSPEND: 1963 case SINGLE_PTRACE: 1964 break; 1965 case SINGLE_UNWIND: 1966 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1967 break; 1968 case SINGLE_EXIT: 1969 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1970 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1971 break; 1972 #ifdef DIAGNOSTIC 1973 default: 1974 panic("single_thread_mode = %d", mode); 1975 #endif 1976 } 1977 pr->ps_single = p; 1978 pr->ps_singlecount = 0; 1979 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1980 int s; 1981 1982 if (q == p) 1983 continue; 1984 if (q->p_flag & P_WEXIT) { 1985 if (mode == SINGLE_EXIT) { 1986 SCHED_LOCK(s); 1987 if (q->p_stat == SSTOP) { 1988 setrunnable(q); 1989 pr->ps_singlecount++; 1990 } 1991 SCHED_UNLOCK(s); 1992 } 1993 continue; 1994 } 1995 SCHED_LOCK(s); 1996 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 1997 switch (q->p_stat) { 1998 case SIDL: 1999 case SRUN: 2000 pr->ps_singlecount++; 2001 break; 2002 case SSLEEP: 2003 /* if it's not interruptible, then just have to wait */ 2004 if (q->p_flag & P_SINTR) { 2005 /* merely need to suspend? just stop it */ 2006 if (mode == SINGLE_SUSPEND || 2007 mode == SINGLE_PTRACE) { 2008 q->p_stat = SSTOP; 2009 break; 2010 } 2011 /* need to unwind or exit, so wake it */ 2012 setrunnable(q); 2013 } 2014 pr->ps_singlecount++; 2015 break; 2016 case SSTOP: 2017 if (mode == SINGLE_EXIT) { 2018 setrunnable(q); 2019 pr->ps_singlecount++; 2020 } 2021 break; 2022 case SDEAD: 2023 break; 2024 case SONPROC: 2025 pr->ps_singlecount++; 2026 signotify(q); 2027 break; 2028 } 2029 SCHED_UNLOCK(s); 2030 } 2031 2032 if (mode != SINGLE_PTRACE) 2033 single_thread_wait(pr); 2034 2035 return 0; 2036 } 2037 2038 void 2039 single_thread_wait(struct process *pr) 2040 { 2041 /* wait until they're all suspended */ 2042 while (pr->ps_singlecount > 0) 2043 tsleep(&pr->ps_singlecount, PUSER, "suspend", 0); 2044 } 2045 2046 void 2047 single_thread_clear(struct proc *p, int flag) 2048 { 2049 struct process *pr = p->p_p; 2050 struct proc *q; 2051 2052 KASSERT(pr->ps_single == p); 2053 KERNEL_ASSERT_LOCKED(); 2054 2055 pr->ps_single = NULL; 2056 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2057 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2058 int s; 2059 2060 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2061 continue; 2062 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2063 2064 /* 2065 * if the thread was only stopped for single threading 2066 * then clearing that either makes it runnable or puts 2067 * it back into some sleep queue 2068 */ 2069 SCHED_LOCK(s); 2070 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2071 if (q->p_wchan == 0) 2072 setrunnable(q); 2073 else 2074 q->p_stat = SSLEEP; 2075 } 2076 SCHED_UNLOCK(s); 2077 } 2078 } 2079 2080 void 2081 sigio_del(struct sigiolst *rmlist) 2082 { 2083 struct sigio *sigio; 2084 2085 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2086 LIST_REMOVE(sigio, sio_pgsigio); 2087 crfree(sigio->sio_ucred); 2088 free(sigio, M_SIGIO, sizeof(*sigio)); 2089 } 2090 } 2091 2092 void 2093 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2094 { 2095 struct sigio *sigio; 2096 2097 MUTEX_ASSERT_LOCKED(&sigio_lock); 2098 2099 sigio = sir->sir_sigio; 2100 if (sigio != NULL) { 2101 KASSERT(sigio->sio_myref == sir); 2102 sir->sir_sigio = NULL; 2103 2104 if (sigio->sio_pgid > 0) 2105 sigio->sio_proc = NULL; 2106 else 2107 sigio->sio_pgrp = NULL; 2108 LIST_REMOVE(sigio, sio_pgsigio); 2109 2110 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2111 } 2112 } 2113 2114 void 2115 sigio_free(struct sigio_ref *sir) 2116 { 2117 struct sigiolst rmlist; 2118 2119 if (sir->sir_sigio == NULL) 2120 return; 2121 2122 LIST_INIT(&rmlist); 2123 2124 mtx_enter(&sigio_lock); 2125 sigio_unlink(sir, &rmlist); 2126 mtx_leave(&sigio_lock); 2127 2128 sigio_del(&rmlist); 2129 } 2130 2131 void 2132 sigio_freelist(struct sigiolst *sigiolst) 2133 { 2134 struct sigiolst rmlist; 2135 struct sigio *sigio; 2136 2137 if (LIST_EMPTY(sigiolst)) 2138 return; 2139 2140 LIST_INIT(&rmlist); 2141 2142 mtx_enter(&sigio_lock); 2143 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2144 sigio_unlink(sigio->sio_myref, &rmlist); 2145 mtx_leave(&sigio_lock); 2146 2147 sigio_del(&rmlist); 2148 } 2149 2150 int 2151 sigio_setown(struct sigio_ref *sir, pid_t pgid) 2152 { 2153 struct sigiolst rmlist; 2154 struct proc *p = curproc; 2155 struct pgrp *pgrp = NULL; 2156 struct process *pr = NULL; 2157 struct sigio *sigio; 2158 int error; 2159 2160 if (pgid == 0) { 2161 sigio_free(sir); 2162 return (0); 2163 } 2164 2165 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2166 sigio->sio_pgid = pgid; 2167 sigio->sio_ucred = crhold(p->p_ucred); 2168 sigio->sio_myref = sir; 2169 2170 LIST_INIT(&rmlist); 2171 2172 /* 2173 * The kernel lock, and not sleeping between prfind()/pgfind() and 2174 * linking of the sigio ensure that the process or process group does 2175 * not disappear unexpectedly. 2176 */ 2177 KERNEL_LOCK(); 2178 mtx_enter(&sigio_lock); 2179 2180 if (pgid > 0) { 2181 pr = prfind(pgid); 2182 if (pr == NULL) { 2183 error = ESRCH; 2184 goto fail; 2185 } 2186 2187 /* 2188 * Policy - Don't allow a process to FSETOWN a process 2189 * in another session. 2190 * 2191 * Remove this test to allow maximum flexibility or 2192 * restrict FSETOWN to the current process or process 2193 * group for maximum safety. 2194 */ 2195 if (pr->ps_session != p->p_p->ps_session) { 2196 error = EPERM; 2197 goto fail; 2198 } 2199 2200 if ((pr->ps_flags & PS_EXITING) != 0) { 2201 error = ESRCH; 2202 goto fail; 2203 } 2204 } else /* if (pgid < 0) */ { 2205 pgrp = pgfind(-pgid); 2206 if (pgrp == NULL) { 2207 error = ESRCH; 2208 goto fail; 2209 } 2210 2211 /* 2212 * Policy - Don't allow a process to FSETOWN a process 2213 * in another session. 2214 * 2215 * Remove this test to allow maximum flexibility or 2216 * restrict FSETOWN to the current process or process 2217 * group for maximum safety. 2218 */ 2219 if (pgrp->pg_session != p->p_p->ps_session) { 2220 error = EPERM; 2221 goto fail; 2222 } 2223 } 2224 2225 if (pgid > 0) { 2226 sigio->sio_proc = pr; 2227 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2228 } else { 2229 sigio->sio_pgrp = pgrp; 2230 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2231 } 2232 2233 sigio_unlink(sir, &rmlist); 2234 sir->sir_sigio = sigio; 2235 2236 mtx_leave(&sigio_lock); 2237 KERNEL_UNLOCK(); 2238 2239 sigio_del(&rmlist); 2240 2241 return (0); 2242 2243 fail: 2244 mtx_leave(&sigio_lock); 2245 KERNEL_UNLOCK(); 2246 2247 crfree(sigio->sio_ucred); 2248 free(sigio, M_SIGIO, sizeof(*sigio)); 2249 2250 return (error); 2251 } 2252 2253 pid_t 2254 sigio_getown(struct sigio_ref *sir) 2255 { 2256 struct sigio *sigio; 2257 pid_t pgid = 0; 2258 2259 mtx_enter(&sigio_lock); 2260 sigio = sir->sir_sigio; 2261 if (sigio != NULL) 2262 pgid = sigio->sio_pgid; 2263 mtx_leave(&sigio_lock); 2264 2265 return (pgid); 2266 } 2267 2268 void 2269 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2270 { 2271 struct sigiolst rmlist; 2272 struct sigio *newsigio, *sigio; 2273 2274 sigio_free(dst); 2275 2276 if (src->sir_sigio == NULL) 2277 return; 2278 2279 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2280 LIST_INIT(&rmlist); 2281 2282 mtx_enter(&sigio_lock); 2283 2284 sigio = src->sir_sigio; 2285 if (sigio == NULL) { 2286 mtx_leave(&sigio_lock); 2287 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2288 return; 2289 } 2290 2291 newsigio->sio_pgid = sigio->sio_pgid; 2292 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2293 newsigio->sio_myref = dst; 2294 if (newsigio->sio_pgid > 0) { 2295 newsigio->sio_proc = sigio->sio_proc; 2296 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2297 sio_pgsigio); 2298 } else { 2299 newsigio->sio_pgrp = sigio->sio_pgrp; 2300 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2301 sio_pgsigio); 2302 } 2303 2304 sigio_unlink(dst, &rmlist); 2305 dst->sir_sigio = newsigio; 2306 2307 mtx_leave(&sigio_lock); 2308 2309 sigio_del(&rmlist); 2310 } 2311