1 /* $OpenBSD: kern_sig.c,v 1.228 2019/02/19 22:42:41 tedu 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 #ifdef DIAGNOSTIC 893 if ((u_int)signum >= NSIG || signum == 0) 894 panic("psignal signal number"); 895 #endif 896 897 /* Ignore signal if the target process is exiting */ 898 if (pr->ps_flags & PS_EXITING) 899 return; 900 901 mask = sigmask(signum); 902 903 if (type == SPROCESS) { 904 /* Accept SIGKILL to coredumping processes */ 905 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 906 if (pr->ps_single != NULL) 907 p = pr->ps_single; 908 atomic_setbits_int(&p->p_siglist, mask); 909 return; 910 } 911 912 /* 913 * If the current thread can process the signal 914 * immediately (it's unblocked) then have it take it. 915 */ 916 q = curproc; 917 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 918 (q->p_sigmask & mask) == 0) 919 p = q; 920 else { 921 /* 922 * A process-wide signal can be diverted to a 923 * different thread that's in sigwait() for this 924 * signal. If there isn't such a thread, then 925 * pick a thread that doesn't have it blocked so 926 * that the stop/kill consideration isn't 927 * delayed. Otherwise, mark it pending on the 928 * main thread. 929 */ 930 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 931 /* ignore exiting threads */ 932 if (q->p_flag & P_WEXIT) 933 continue; 934 935 /* skip threads that have the signal blocked */ 936 if ((q->p_sigmask & mask) != 0) 937 continue; 938 939 /* okay, could send to this thread */ 940 p = q; 941 942 /* 943 * sigsuspend, sigwait, ppoll/pselect, etc? 944 * Definitely go to this thread, as it's 945 * already blocked in the kernel. 946 */ 947 if (q->p_flag & P_SIGSUSPEND) 948 break; 949 } 950 } 951 } 952 953 if (type != SPROPAGATED) 954 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 955 956 prop = sigprop[signum]; 957 958 /* 959 * If proc is traced, always give parent a chance. 960 */ 961 if (pr->ps_flags & PS_TRACED) { 962 action = SIG_DFL; 963 atomic_setbits_int(&p->p_siglist, mask); 964 } else { 965 /* 966 * If the signal is being ignored, 967 * then we forget about it immediately. 968 * (Note: we don't set SIGCONT in ps_sigignore, 969 * and if it is set to SIG_IGN, 970 * action will be SIG_DFL here.) 971 */ 972 if (pr->ps_sigacts->ps_sigignore & mask) 973 return; 974 if (p->p_sigmask & mask) { 975 action = SIG_HOLD; 976 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 977 action = SIG_CATCH; 978 } else { 979 action = SIG_DFL; 980 981 if (prop & SA_KILL && pr->ps_nice > NZERO) 982 pr->ps_nice = NZERO; 983 984 /* 985 * If sending a tty stop signal to a member of an 986 * orphaned process group, discard the signal here if 987 * the action is default; don't stop the process below 988 * if sleeping, and don't clear any pending SIGCONT. 989 */ 990 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 991 return; 992 } 993 994 atomic_setbits_int(&p->p_siglist, mask); 995 } 996 997 if (prop & SA_CONT) 998 atomic_clearbits_int(&p->p_siglist, stopsigmask); 999 1000 if (prop & SA_STOP) { 1001 atomic_clearbits_int(&p->p_siglist, contsigmask); 1002 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1003 } 1004 1005 /* 1006 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1007 */ 1008 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1009 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1010 if (q != p) 1011 ptsignal(q, signum, SPROPAGATED); 1012 1013 /* 1014 * Defer further processing for signals which are held, 1015 * except that stopped processes must be continued by SIGCONT. 1016 */ 1017 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 1018 return; 1019 1020 SCHED_LOCK(s); 1021 1022 switch (p->p_stat) { 1023 1024 case SSLEEP: 1025 /* 1026 * If process is sleeping uninterruptibly 1027 * we can't interrupt the sleep... the signal will 1028 * be noticed when the process returns through 1029 * trap() or syscall(). 1030 */ 1031 if ((p->p_flag & P_SINTR) == 0) 1032 goto out; 1033 /* 1034 * Process is sleeping and traced... make it runnable 1035 * so it can discover the signal in issignal() and stop 1036 * for the parent. 1037 */ 1038 if (pr->ps_flags & PS_TRACED) 1039 goto run; 1040 /* 1041 * If SIGCONT is default (or ignored) and process is 1042 * asleep, we are finished; the process should not 1043 * be awakened. 1044 */ 1045 if ((prop & SA_CONT) && action == SIG_DFL) { 1046 atomic_clearbits_int(&p->p_siglist, mask); 1047 goto out; 1048 } 1049 /* 1050 * When a sleeping process receives a stop 1051 * signal, process immediately if possible. 1052 */ 1053 if ((prop & SA_STOP) && action == SIG_DFL) { 1054 /* 1055 * If a child holding parent blocked, 1056 * stopping could cause deadlock. 1057 */ 1058 if (pr->ps_flags & PS_PPWAIT) 1059 goto out; 1060 atomic_clearbits_int(&p->p_siglist, mask); 1061 p->p_xstat = signum; 1062 proc_stop(p, 0); 1063 goto out; 1064 } 1065 /* 1066 * All other (caught or default) signals 1067 * cause the process to run. 1068 */ 1069 goto runfast; 1070 /*NOTREACHED*/ 1071 1072 case SSTOP: 1073 /* 1074 * If traced process is already stopped, 1075 * then no further action is necessary. 1076 */ 1077 if (pr->ps_flags & PS_TRACED) 1078 goto out; 1079 1080 /* 1081 * Kill signal always sets processes running. 1082 */ 1083 if (signum == SIGKILL) { 1084 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1085 goto runfast; 1086 } 1087 1088 if (prop & SA_CONT) { 1089 /* 1090 * If SIGCONT is default (or ignored), we continue the 1091 * process but don't leave the signal in p_siglist, as 1092 * it has no further action. If SIGCONT is held, we 1093 * continue the process and leave the signal in 1094 * p_siglist. If the process catches SIGCONT, let it 1095 * handle the signal itself. If it isn't waiting on 1096 * an event, then it goes back to run state. 1097 * Otherwise, process goes back to sleep state. 1098 */ 1099 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1100 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1101 wakeparent = 1; 1102 if (action == SIG_DFL) 1103 atomic_clearbits_int(&p->p_siglist, mask); 1104 if (action == SIG_CATCH) 1105 goto runfast; 1106 if (p->p_wchan == 0) 1107 goto run; 1108 p->p_stat = SSLEEP; 1109 goto out; 1110 } 1111 1112 if (prop & SA_STOP) { 1113 /* 1114 * Already stopped, don't need to stop again. 1115 * (If we did the shell could get confused.) 1116 */ 1117 atomic_clearbits_int(&p->p_siglist, mask); 1118 goto out; 1119 } 1120 1121 /* 1122 * If process is sleeping interruptibly, then simulate a 1123 * wakeup so that when it is continued, it will be made 1124 * runnable and can look at the signal. But don't make 1125 * the process runnable, leave it stopped. 1126 */ 1127 if (p->p_wchan && p->p_flag & P_SINTR) 1128 unsleep(p); 1129 goto out; 1130 1131 case SONPROC: 1132 signotify(p); 1133 /* FALLTHROUGH */ 1134 default: 1135 /* 1136 * SRUN, SIDL, SDEAD do nothing with the signal, 1137 * other than kicking ourselves if we are running. 1138 * It will either never be noticed, or noticed very soon. 1139 */ 1140 goto out; 1141 } 1142 /*NOTREACHED*/ 1143 1144 runfast: 1145 /* 1146 * Raise priority to at least PUSER. 1147 */ 1148 if (p->p_priority > PUSER) 1149 p->p_priority = PUSER; 1150 run: 1151 setrunnable(p); 1152 out: 1153 SCHED_UNLOCK(s); 1154 if (wakeparent) 1155 wakeup(pr->ps_pptr); 1156 } 1157 1158 /* 1159 * If the current process has received a signal (should be caught or cause 1160 * termination, should interrupt current syscall), return the signal number. 1161 * Stop signals with default action are processed immediately, then cleared; 1162 * they aren't returned. This is checked after each entry to the system for 1163 * a syscall or trap (though this can usually be done without calling issignal 1164 * by checking the pending signal masks in the CURSIG macro.) The normal call 1165 * sequence is 1166 * 1167 * while (signum = CURSIG(curproc)) 1168 * postsig(signum); 1169 * 1170 * Assumes that if the P_SINTR flag is set, we're holding both the 1171 * kernel and scheduler locks. 1172 */ 1173 int 1174 issignal(struct proc *p) 1175 { 1176 struct process *pr = p->p_p; 1177 int signum, mask, prop; 1178 int dolock = (p->p_flag & P_SINTR) == 0; 1179 int s; 1180 1181 for (;;) { 1182 mask = p->p_siglist & ~p->p_sigmask; 1183 if (pr->ps_flags & PS_PPWAIT) 1184 mask &= ~stopsigmask; 1185 if (mask == 0) /* no signal to send */ 1186 return (0); 1187 signum = ffs((long)mask); 1188 mask = sigmask(signum); 1189 atomic_clearbits_int(&p->p_siglist, mask); 1190 1191 /* 1192 * We should see pending but ignored signals 1193 * only if PS_TRACED was on when they were posted. 1194 */ 1195 if (mask & pr->ps_sigacts->ps_sigignore && 1196 (pr->ps_flags & PS_TRACED) == 0) 1197 continue; 1198 1199 /* 1200 * If traced, always stop, and stay stopped until released 1201 * by the debugger. If our parent process is waiting for 1202 * us, don't hang as we could deadlock. 1203 */ 1204 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1205 signum != SIGKILL) { 1206 p->p_xstat = signum; 1207 1208 if (dolock) 1209 KERNEL_LOCK(); 1210 single_thread_set(p, SINGLE_PTRACE, 0); 1211 if (dolock) 1212 KERNEL_UNLOCK(); 1213 1214 if (dolock) 1215 SCHED_LOCK(s); 1216 proc_stop(p, 1); 1217 if (dolock) 1218 SCHED_UNLOCK(s); 1219 1220 if (dolock) 1221 KERNEL_LOCK(); 1222 single_thread_clear(p, 0); 1223 if (dolock) 1224 KERNEL_UNLOCK(); 1225 1226 /* 1227 * If we are no longer being traced, or the parent 1228 * didn't give us a signal, look for more signals. 1229 */ 1230 if ((pr->ps_flags & PS_TRACED) == 0 || p->p_xstat == 0) 1231 continue; 1232 1233 /* 1234 * If the new signal is being masked, look for other 1235 * signals. 1236 */ 1237 signum = p->p_xstat; 1238 mask = sigmask(signum); 1239 if ((p->p_sigmask & mask) != 0) 1240 continue; 1241 1242 /* take the signal! */ 1243 atomic_clearbits_int(&p->p_siglist, mask); 1244 } 1245 1246 prop = sigprop[signum]; 1247 1248 /* 1249 * Decide whether the signal should be returned. 1250 * Return the signal's number, or fall through 1251 * to clear it from the pending mask. 1252 */ 1253 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1254 case (long)SIG_DFL: 1255 /* 1256 * Don't take default actions on system processes. 1257 */ 1258 if (pr->ps_pid <= 1) { 1259 #ifdef DIAGNOSTIC 1260 /* 1261 * Are you sure you want to ignore SIGSEGV 1262 * in init? XXX 1263 */ 1264 printf("Process (pid %d) got signal" 1265 " %d\n", pr->ps_pid, signum); 1266 #endif 1267 break; /* == ignore */ 1268 } 1269 /* 1270 * If there is a pending stop signal to process 1271 * with default action, stop here, 1272 * then clear the signal. However, 1273 * if process is member of an orphaned 1274 * process group, ignore tty stop signals. 1275 */ 1276 if (prop & SA_STOP) { 1277 if (pr->ps_flags & PS_TRACED || 1278 (pr->ps_pgrp->pg_jobc == 0 && 1279 prop & SA_TTYSTOP)) 1280 break; /* == ignore */ 1281 p->p_xstat = signum; 1282 if (dolock) 1283 SCHED_LOCK(s); 1284 proc_stop(p, 1); 1285 if (dolock) 1286 SCHED_UNLOCK(s); 1287 break; 1288 } else if (prop & SA_IGNORE) { 1289 /* 1290 * Except for SIGCONT, shouldn't get here. 1291 * Default action is to ignore; drop it. 1292 */ 1293 break; /* == ignore */ 1294 } else 1295 goto keep; 1296 /*NOTREACHED*/ 1297 case (long)SIG_IGN: 1298 /* 1299 * Masking above should prevent us ever trying 1300 * to take action on an ignored signal other 1301 * than SIGCONT, unless process is traced. 1302 */ 1303 if ((prop & SA_CONT) == 0 && 1304 (pr->ps_flags & PS_TRACED) == 0) 1305 printf("issignal\n"); 1306 break; /* == ignore */ 1307 default: 1308 /* 1309 * This signal has an action, let 1310 * postsig() process it. 1311 */ 1312 goto keep; 1313 } 1314 } 1315 /* NOTREACHED */ 1316 1317 keep: 1318 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1319 return (signum); 1320 } 1321 1322 /* 1323 * Put the argument process into the stopped state and notify the parent 1324 * via wakeup. Signals are handled elsewhere. The process must not be 1325 * on the run queue. 1326 */ 1327 void 1328 proc_stop(struct proc *p, int sw) 1329 { 1330 struct process *pr = p->p_p; 1331 extern void *softclock_si; 1332 1333 #ifdef MULTIPROCESSOR 1334 SCHED_ASSERT_LOCKED(); 1335 #endif 1336 1337 p->p_stat = SSTOP; 1338 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1339 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1340 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1341 if (!timeout_pending(&proc_stop_to)) { 1342 timeout_add(&proc_stop_to, 0); 1343 /* 1344 * We need this soft interrupt to be handled fast. 1345 * Extra calls to softclock don't hurt. 1346 */ 1347 softintr_schedule(softclock_si); 1348 } 1349 if (sw) 1350 mi_switch(); 1351 } 1352 1353 /* 1354 * Called from a timeout to send signals to the parents of stopped processes. 1355 * We can't do this in proc_stop because it's called with nasty locks held 1356 * and we would need recursive scheduler lock to deal with that. 1357 */ 1358 void 1359 proc_stop_sweep(void *v) 1360 { 1361 struct process *pr; 1362 1363 LIST_FOREACH(pr, &allprocess, ps_list) { 1364 if ((pr->ps_flags & PS_STOPPED) == 0) 1365 continue; 1366 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1367 1368 if ((pr->ps_pptr->ps_sigacts->ps_flags & SAS_NOCLDSTOP) == 0) 1369 prsignal(pr->ps_pptr, SIGCHLD); 1370 wakeup(pr->ps_pptr); 1371 } 1372 } 1373 1374 /* 1375 * Take the action for the specified signal 1376 * from the current set of pending signals. 1377 */ 1378 void 1379 postsig(struct proc *p, int signum) 1380 { 1381 struct process *pr = p->p_p; 1382 struct sigacts *ps = pr->ps_sigacts; 1383 sig_t action; 1384 u_long trapno; 1385 int mask, returnmask; 1386 siginfo_t si; 1387 union sigval sigval; 1388 int s, code; 1389 1390 KASSERT(signum != 0); 1391 KERNEL_ASSERT_LOCKED(); 1392 1393 mask = sigmask(signum); 1394 atomic_clearbits_int(&p->p_siglist, mask); 1395 action = ps->ps_sigact[signum]; 1396 sigval.sival_ptr = 0; 1397 1398 if (p->p_sisig != signum) { 1399 trapno = 0; 1400 code = SI_USER; 1401 sigval.sival_ptr = 0; 1402 } else { 1403 trapno = p->p_sitrapno; 1404 code = p->p_sicode; 1405 sigval = p->p_sigval; 1406 } 1407 initsiginfo(&si, signum, trapno, code, sigval); 1408 1409 #ifdef KTRACE 1410 if (KTRPOINT(p, KTR_PSIG)) { 1411 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1412 p->p_oldmask : p->p_sigmask, code, &si); 1413 } 1414 #endif 1415 if (action == SIG_DFL) { 1416 /* 1417 * Default action, where the default is to kill 1418 * the process. (Other cases were ignored above.) 1419 */ 1420 sigexit(p, signum); 1421 /* NOTREACHED */ 1422 } else { 1423 /* 1424 * If we get here, the signal must be caught. 1425 */ 1426 #ifdef DIAGNOSTIC 1427 if (action == SIG_IGN || (p->p_sigmask & mask)) 1428 panic("postsig action"); 1429 #endif 1430 /* 1431 * Set the new mask value and also defer further 1432 * occurrences of this signal. 1433 * 1434 * Special case: user has done a sigpause. Here the 1435 * current mask is not of interest, but rather the 1436 * mask from before the sigpause is what we want 1437 * restored after the signal processing is completed. 1438 */ 1439 #ifdef MULTIPROCESSOR 1440 s = splsched(); 1441 #else 1442 s = splhigh(); 1443 #endif 1444 if (p->p_flag & P_SIGSUSPEND) { 1445 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1446 returnmask = p->p_oldmask; 1447 } else { 1448 returnmask = p->p_sigmask; 1449 } 1450 if (p->p_sisig == signum) { 1451 p->p_sisig = 0; 1452 p->p_sitrapno = 0; 1453 p->p_sicode = SI_USER; 1454 p->p_sigval.sival_ptr = NULL; 1455 } 1456 1457 sendsig(action, signum, returnmask, &si); 1458 postsig_done(p, signum, ps); 1459 splx(s); 1460 } 1461 } 1462 1463 /* 1464 * Force the current process to exit with the specified signal, dumping core 1465 * if appropriate. We bypass the normal tests for masked and caught signals, 1466 * allowing unrecoverable failures to terminate the process without changing 1467 * signal state. Mark the accounting record with the signal termination. 1468 * If dumping core, save the signal number for the debugger. Calls exit and 1469 * does not return. 1470 */ 1471 void 1472 sigexit(struct proc *p, int signum) 1473 { 1474 /* Mark process as going away */ 1475 atomic_setbits_int(&p->p_flag, P_WEXIT); 1476 1477 p->p_p->ps_acflag |= AXSIG; 1478 if (sigprop[signum] & SA_CORE) { 1479 p->p_sisig = signum; 1480 1481 /* if there are other threads, pause them */ 1482 if (P_HASSIBLING(p)) 1483 single_thread_set(p, SINGLE_SUSPEND, 0); 1484 1485 if (coredump(p) == 0) 1486 signum |= WCOREFLAG; 1487 } 1488 exit1(p, W_EXITCODE(0, signum), EXIT_NORMAL); 1489 /* NOTREACHED */ 1490 } 1491 1492 int nosuidcoredump = 1; 1493 1494 struct coredump_iostate { 1495 struct proc *io_proc; 1496 struct vnode *io_vp; 1497 struct ucred *io_cred; 1498 off_t io_offset; 1499 }; 1500 1501 /* 1502 * Dump core, into a file named "progname.core", unless the process was 1503 * setuid/setgid. 1504 */ 1505 int 1506 coredump(struct proc *p) 1507 { 1508 #ifdef SMALL_KERNEL 1509 return EPERM; 1510 #else 1511 struct process *pr = p->p_p; 1512 struct vnode *vp; 1513 struct ucred *cred = p->p_ucred; 1514 struct vmspace *vm = p->p_vmspace; 1515 struct nameidata nd; 1516 struct vattr vattr; 1517 struct coredump_iostate io; 1518 int error, len, incrash = 0; 1519 char name[MAXPATHLEN]; 1520 const char *dir = "/var/crash"; 1521 1522 if (pr->ps_emul->e_coredump == NULL) 1523 return (EINVAL); 1524 1525 pr->ps_flags |= PS_COREDUMP; 1526 1527 /* 1528 * If the process has inconsistent uids, nosuidcoredump 1529 * determines coredump placement policy. 1530 */ 1531 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1532 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1533 if (nosuidcoredump == 3 || nosuidcoredump == 2) 1534 incrash = 1; 1535 else 1536 return (EPERM); 1537 } 1538 1539 /* Don't dump if will exceed file size limit. */ 1540 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= 1541 p->p_rlimit[RLIMIT_CORE].rlim_cur) 1542 return (EFBIG); 1543 1544 if (incrash && nosuidcoredump == 3) { 1545 /* 1546 * If the program directory does not exist, dumps of 1547 * that core will silently fail. 1548 */ 1549 len = snprintf(name, sizeof(name), "%s/%s/%u.core", 1550 dir, pr->ps_comm, pr->ps_pid); 1551 } else if (incrash && nosuidcoredump == 2) 1552 len = snprintf(name, sizeof(name), "%s/%s.core", 1553 dir, pr->ps_comm); 1554 else 1555 len = snprintf(name, sizeof(name), "%s.core", pr->ps_comm); 1556 if (len >= sizeof(name)) 1557 return (EACCES); 1558 1559 /* 1560 * Control the UID used to write out. The normal case uses 1561 * the real UID. If the sugid case is going to write into the 1562 * controlled directory, we do so as root. 1563 */ 1564 if (incrash == 0) { 1565 cred = crdup(cred); 1566 cred->cr_uid = cred->cr_ruid; 1567 cred->cr_gid = cred->cr_rgid; 1568 } else { 1569 if (p->p_fd->fd_rdir) { 1570 vrele(p->p_fd->fd_rdir); 1571 p->p_fd->fd_rdir = NULL; 1572 } 1573 p->p_ucred = crdup(p->p_ucred); 1574 crfree(cred); 1575 cred = p->p_ucred; 1576 crhold(cred); 1577 cred->cr_uid = 0; 1578 cred->cr_gid = 0; 1579 } 1580 1581 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); 1582 1583 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1584 S_IRUSR | S_IWUSR); 1585 1586 if (error) 1587 goto out; 1588 1589 /* 1590 * Don't dump to non-regular files, files with links, or files 1591 * owned by someone else. 1592 */ 1593 vp = nd.ni_vp; 1594 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1595 VOP_UNLOCK(vp); 1596 vn_close(vp, FWRITE, cred, p); 1597 goto out; 1598 } 1599 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1600 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1601 vattr.va_uid != cred->cr_uid) { 1602 error = EACCES; 1603 VOP_UNLOCK(vp); 1604 vn_close(vp, FWRITE, cred, p); 1605 goto out; 1606 } 1607 VATTR_NULL(&vattr); 1608 vattr.va_size = 0; 1609 VOP_SETATTR(vp, &vattr, cred, p); 1610 pr->ps_acflag |= ACORE; 1611 1612 io.io_proc = p; 1613 io.io_vp = vp; 1614 io.io_cred = cred; 1615 io.io_offset = 0; 1616 VOP_UNLOCK(vp); 1617 vref(vp); 1618 error = vn_close(vp, FWRITE, cred, p); 1619 if (error == 0) 1620 error = (*pr->ps_emul->e_coredump)(p, &io); 1621 vrele(vp); 1622 out: 1623 crfree(cred); 1624 return (error); 1625 #endif 1626 } 1627 1628 #ifndef SMALL_KERNEL 1629 int 1630 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1631 { 1632 struct coredump_iostate *io = cookie; 1633 off_t coffset = 0; 1634 size_t csize; 1635 int chunk, error; 1636 1637 csize = len; 1638 do { 1639 if (io->io_proc->p_siglist & sigmask(SIGKILL)) 1640 return (EINTR); 1641 1642 /* Rest of the loop sleeps with lock held, so... */ 1643 yield(); 1644 1645 chunk = MIN(csize, MAXPHYS); 1646 error = vn_rdwr(UIO_WRITE, io->io_vp, 1647 (caddr_t)data + coffset, chunk, 1648 io->io_offset + coffset, segflg, 1649 IO_UNIT, io->io_cred, NULL, io->io_proc); 1650 if (error) { 1651 struct process *pr = io->io_proc->p_p; 1652 1653 if (error == ENOSPC) 1654 log(LOG_ERR, 1655 "coredump of %s(%d) failed, filesystem full\n", 1656 pr->ps_comm, pr->ps_pid); 1657 else 1658 log(LOG_ERR, 1659 "coredump of %s(%d), write failed: errno %d\n", 1660 pr->ps_comm, pr->ps_pid, error); 1661 return (error); 1662 } 1663 1664 coffset += chunk; 1665 csize -= chunk; 1666 } while (csize > 0); 1667 1668 io->io_offset += len; 1669 return (0); 1670 } 1671 1672 void 1673 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1674 { 1675 struct coredump_iostate *io = cookie; 1676 1677 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1678 } 1679 1680 #endif /* !SMALL_KERNEL */ 1681 1682 /* 1683 * Nonexistent system call-- signal process (may want to handle it). 1684 * Flag error in case process won't see signal immediately (blocked or ignored). 1685 */ 1686 int 1687 sys_nosys(struct proc *p, void *v, register_t *retval) 1688 { 1689 1690 ptsignal(p, SIGSYS, STHREAD); 1691 return (ENOSYS); 1692 } 1693 1694 int 1695 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1696 { 1697 static int sigwaitsleep; 1698 struct sys___thrsigdivert_args /* { 1699 syscallarg(sigset_t) sigmask; 1700 syscallarg(siginfo_t *) info; 1701 syscallarg(const struct timespec *) timeout; 1702 } */ *uap = v; 1703 struct process *pr = p->p_p; 1704 sigset_t *m; 1705 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1706 siginfo_t si; 1707 uint64_t to_ticks = 0; 1708 int timeinvalid = 0; 1709 int error = 0; 1710 1711 memset(&si, 0, sizeof(si)); 1712 1713 if (SCARG(uap, timeout) != NULL) { 1714 struct timespec ts; 1715 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1716 return (error); 1717 #ifdef KTRACE 1718 if (KTRPOINT(p, KTR_STRUCT)) 1719 ktrreltimespec(p, &ts); 1720 #endif 1721 if (!timespecisvalid(&ts)) 1722 timeinvalid = 1; 1723 else { 1724 to_ticks = (uint64_t)hz * ts.tv_sec + 1725 ts.tv_nsec / (tick * 1000); 1726 if (to_ticks > INT_MAX) 1727 to_ticks = INT_MAX; 1728 if (to_ticks == 0 && ts.tv_nsec) 1729 to_ticks = 1; 1730 } 1731 } 1732 1733 dosigsuspend(p, p->p_sigmask &~ mask); 1734 for (;;) { 1735 si.si_signo = CURSIG(p); 1736 if (si.si_signo != 0) { 1737 sigset_t smask = sigmask(si.si_signo); 1738 if (smask & mask) { 1739 if (p->p_siglist & smask) 1740 m = &p->p_siglist; 1741 else if (pr->ps_mainproc->p_siglist & smask) 1742 m = &pr->ps_mainproc->p_siglist; 1743 else { 1744 /* signal got eaten by someone else? */ 1745 continue; 1746 } 1747 atomic_clearbits_int(m, smask); 1748 error = 0; 1749 break; 1750 } 1751 } 1752 1753 /* per-POSIX, delay this error until after the above */ 1754 if (timeinvalid) 1755 error = EINVAL; 1756 1757 if (SCARG(uap, timeout) != NULL && to_ticks == 0) 1758 error = EAGAIN; 1759 1760 if (error != 0) 1761 break; 1762 1763 error = tsleep(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1764 (int)to_ticks); 1765 } 1766 1767 if (error == 0) { 1768 *retval = si.si_signo; 1769 if (SCARG(uap, info) != NULL) 1770 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1771 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1772 /* 1773 * Restarting is wrong if there's a timeout, as it'll be 1774 * for the same interval again 1775 */ 1776 error = EINTR; 1777 } 1778 1779 return (error); 1780 } 1781 1782 void 1783 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1784 { 1785 memset(si, 0, sizeof(*si)); 1786 1787 si->si_signo = sig; 1788 si->si_code = code; 1789 if (code == SI_USER) { 1790 si->si_value = val; 1791 } else { 1792 switch (sig) { 1793 case SIGSEGV: 1794 case SIGILL: 1795 case SIGBUS: 1796 case SIGFPE: 1797 si->si_addr = val.sival_ptr; 1798 si->si_trapno = trapno; 1799 break; 1800 case SIGXFSZ: 1801 break; 1802 } 1803 } 1804 } 1805 1806 int 1807 filt_sigattach(struct knote *kn) 1808 { 1809 struct process *pr = curproc->p_p; 1810 1811 if (kn->kn_id >= NSIG) 1812 return EINVAL; 1813 1814 kn->kn_ptr.p_process = pr; 1815 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1816 1817 /* XXX lock the proc here while adding to the list? */ 1818 SLIST_INSERT_HEAD(&pr->ps_klist, kn, kn_selnext); 1819 1820 return (0); 1821 } 1822 1823 void 1824 filt_sigdetach(struct knote *kn) 1825 { 1826 struct process *pr = kn->kn_ptr.p_process; 1827 1828 SLIST_REMOVE(&pr->ps_klist, kn, knote, kn_selnext); 1829 } 1830 1831 /* 1832 * signal knotes are shared with proc knotes, so we apply a mask to 1833 * the hint in order to differentiate them from process hints. This 1834 * could be avoided by using a signal-specific knote list, but probably 1835 * isn't worth the trouble. 1836 */ 1837 int 1838 filt_signal(struct knote *kn, long hint) 1839 { 1840 1841 if (hint & NOTE_SIGNAL) { 1842 hint &= ~NOTE_SIGNAL; 1843 1844 if (kn->kn_id == hint) 1845 kn->kn_data++; 1846 } 1847 return (kn->kn_data != 0); 1848 } 1849 1850 void 1851 userret(struct proc *p) 1852 { 1853 int signum; 1854 1855 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1856 if (p->p_flag & P_PROFPEND) { 1857 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1858 KERNEL_LOCK(); 1859 psignal(p, SIGPROF); 1860 KERNEL_UNLOCK(); 1861 } 1862 if (p->p_flag & P_ALRMPEND) { 1863 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1864 KERNEL_LOCK(); 1865 psignal(p, SIGVTALRM); 1866 KERNEL_UNLOCK(); 1867 } 1868 1869 if (SIGPENDING(p)) { 1870 KERNEL_LOCK(); 1871 while ((signum = CURSIG(p)) != 0) 1872 postsig(p, signum); 1873 KERNEL_UNLOCK(); 1874 } 1875 1876 /* 1877 * If P_SIGSUSPEND is still set here, then we still need to restore 1878 * the original sigmask before returning to userspace. Also, this 1879 * might unmask some pending signals, so we need to check a second 1880 * time for signals to post. 1881 */ 1882 if (p->p_flag & P_SIGSUSPEND) { 1883 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1884 p->p_sigmask = p->p_oldmask; 1885 1886 KERNEL_LOCK(); 1887 while ((signum = CURSIG(p)) != 0) 1888 postsig(p, signum); 1889 KERNEL_UNLOCK(); 1890 } 1891 1892 if (p->p_flag & P_SUSPSINGLE) { 1893 KERNEL_LOCK(); 1894 single_thread_check(p, 0); 1895 KERNEL_UNLOCK(); 1896 } 1897 1898 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1899 1900 p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; 1901 } 1902 1903 int 1904 single_thread_check(struct proc *p, int deep) 1905 { 1906 struct process *pr = p->p_p; 1907 1908 if (pr->ps_single != NULL && pr->ps_single != p) { 1909 do { 1910 int s; 1911 1912 /* if we're in deep, we need to unwind to the edge */ 1913 if (deep) { 1914 if (pr->ps_flags & PS_SINGLEUNWIND) 1915 return (ERESTART); 1916 if (pr->ps_flags & PS_SINGLEEXIT) 1917 return (EINTR); 1918 } 1919 1920 if (--pr->ps_singlecount == 0) 1921 wakeup(&pr->ps_singlecount); 1922 if (pr->ps_flags & PS_SINGLEEXIT) 1923 exit1(p, 0, EXIT_THREAD_NOCHECK); 1924 1925 /* not exiting and don't need to unwind, so suspend */ 1926 SCHED_LOCK(s); 1927 p->p_stat = SSTOP; 1928 mi_switch(); 1929 SCHED_UNLOCK(s); 1930 } while (pr->ps_single != NULL); 1931 } 1932 1933 return (0); 1934 } 1935 1936 /* 1937 * Stop other threads in the process. The mode controls how and 1938 * where the other threads should stop: 1939 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1940 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1941 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1942 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1943 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1944 * or released as with SINGLE_SUSPEND 1945 * - SINGLE_EXIT: unwind to kernel boundary and exit 1946 */ 1947 int 1948 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1949 { 1950 struct process *pr = p->p_p; 1951 struct proc *q; 1952 int error; 1953 1954 KERNEL_ASSERT_LOCKED(); 1955 1956 if ((error = single_thread_check(p, deep))) 1957 return error; 1958 1959 switch (mode) { 1960 case SINGLE_SUSPEND: 1961 case SINGLE_PTRACE: 1962 break; 1963 case SINGLE_UNWIND: 1964 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1965 break; 1966 case SINGLE_EXIT: 1967 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1968 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1969 break; 1970 #ifdef DIAGNOSTIC 1971 default: 1972 panic("single_thread_mode = %d", mode); 1973 #endif 1974 } 1975 pr->ps_single = p; 1976 pr->ps_singlecount = 0; 1977 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1978 int s; 1979 1980 if (q == p) 1981 continue; 1982 if (q->p_flag & P_WEXIT) { 1983 if (mode == SINGLE_EXIT) { 1984 SCHED_LOCK(s); 1985 if (q->p_stat == SSTOP) { 1986 setrunnable(q); 1987 pr->ps_singlecount++; 1988 } 1989 SCHED_UNLOCK(s); 1990 } 1991 continue; 1992 } 1993 SCHED_LOCK(s); 1994 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 1995 switch (q->p_stat) { 1996 case SIDL: 1997 case SRUN: 1998 pr->ps_singlecount++; 1999 break; 2000 case SSLEEP: 2001 /* if it's not interruptible, then just have to wait */ 2002 if (q->p_flag & P_SINTR) { 2003 /* merely need to suspend? just stop it */ 2004 if (mode == SINGLE_SUSPEND || 2005 mode == SINGLE_PTRACE) { 2006 q->p_stat = SSTOP; 2007 break; 2008 } 2009 /* need to unwind or exit, so wake it */ 2010 setrunnable(q); 2011 } 2012 pr->ps_singlecount++; 2013 break; 2014 case SSTOP: 2015 if (mode == SINGLE_EXIT) { 2016 setrunnable(q); 2017 pr->ps_singlecount++; 2018 } 2019 break; 2020 case SDEAD: 2021 break; 2022 case SONPROC: 2023 pr->ps_singlecount++; 2024 signotify(q); 2025 break; 2026 } 2027 SCHED_UNLOCK(s); 2028 } 2029 2030 if (mode != SINGLE_PTRACE) 2031 single_thread_wait(pr); 2032 2033 return 0; 2034 } 2035 2036 void 2037 single_thread_wait(struct process *pr) 2038 { 2039 /* wait until they're all suspended */ 2040 while (pr->ps_singlecount > 0) 2041 tsleep(&pr->ps_singlecount, PUSER, "suspend", 0); 2042 } 2043 2044 void 2045 single_thread_clear(struct proc *p, int flag) 2046 { 2047 struct process *pr = p->p_p; 2048 struct proc *q; 2049 2050 KASSERT(pr->ps_single == p); 2051 KERNEL_ASSERT_LOCKED(); 2052 2053 pr->ps_single = NULL; 2054 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2055 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2056 int s; 2057 2058 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2059 continue; 2060 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2061 2062 /* 2063 * if the thread was only stopped for single threading 2064 * then clearing that either makes it runnable or puts 2065 * it back into some sleep queue 2066 */ 2067 SCHED_LOCK(s); 2068 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2069 if (q->p_wchan == 0) 2070 setrunnable(q); 2071 else 2072 q->p_stat = SSLEEP; 2073 } 2074 SCHED_UNLOCK(s); 2075 } 2076 } 2077 2078 void 2079 sigio_del(struct sigiolst *rmlist) 2080 { 2081 struct sigio *sigio; 2082 2083 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2084 LIST_REMOVE(sigio, sio_pgsigio); 2085 crfree(sigio->sio_ucred); 2086 free(sigio, M_SIGIO, sizeof(*sigio)); 2087 } 2088 } 2089 2090 void 2091 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2092 { 2093 struct sigio *sigio; 2094 2095 MUTEX_ASSERT_LOCKED(&sigio_lock); 2096 2097 sigio = sir->sir_sigio; 2098 if (sigio != NULL) { 2099 KASSERT(sigio->sio_myref == sir); 2100 sir->sir_sigio = NULL; 2101 2102 if (sigio->sio_pgid > 0) 2103 sigio->sio_proc = NULL; 2104 else 2105 sigio->sio_pgrp = NULL; 2106 LIST_REMOVE(sigio, sio_pgsigio); 2107 2108 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2109 } 2110 } 2111 2112 void 2113 sigio_free(struct sigio_ref *sir) 2114 { 2115 struct sigiolst rmlist; 2116 2117 if (sir->sir_sigio == NULL) 2118 return; 2119 2120 LIST_INIT(&rmlist); 2121 2122 mtx_enter(&sigio_lock); 2123 sigio_unlink(sir, &rmlist); 2124 mtx_leave(&sigio_lock); 2125 2126 sigio_del(&rmlist); 2127 } 2128 2129 void 2130 sigio_freelist(struct sigiolst *sigiolst) 2131 { 2132 struct sigiolst rmlist; 2133 struct sigio *sigio; 2134 2135 if (LIST_EMPTY(sigiolst)) 2136 return; 2137 2138 LIST_INIT(&rmlist); 2139 2140 mtx_enter(&sigio_lock); 2141 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2142 sigio_unlink(sigio->sio_myref, &rmlist); 2143 mtx_leave(&sigio_lock); 2144 2145 sigio_del(&rmlist); 2146 } 2147 2148 int 2149 sigio_setown(struct sigio_ref *sir, pid_t pgid) 2150 { 2151 struct sigiolst rmlist; 2152 struct proc *p = curproc; 2153 struct pgrp *pgrp = NULL; 2154 struct process *pr = NULL; 2155 struct sigio *sigio; 2156 int error; 2157 2158 if (pgid == 0) { 2159 sigio_free(sir); 2160 return (0); 2161 } 2162 2163 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2164 sigio->sio_pgid = pgid; 2165 sigio->sio_ucred = crhold(p->p_ucred); 2166 sigio->sio_myref = sir; 2167 2168 LIST_INIT(&rmlist); 2169 2170 /* 2171 * The kernel lock, and not sleeping between prfind()/pgfind() and 2172 * linking of the sigio ensure that the process or process group does 2173 * not disappear unexpectedly. 2174 */ 2175 KERNEL_LOCK(); 2176 mtx_enter(&sigio_lock); 2177 2178 if (pgid > 0) { 2179 pr = prfind(pgid); 2180 if (pr == NULL) { 2181 error = ESRCH; 2182 goto fail; 2183 } 2184 2185 /* 2186 * Policy - Don't allow a process to FSETOWN a process 2187 * in another session. 2188 * 2189 * Remove this test to allow maximum flexibility or 2190 * restrict FSETOWN to the current process or process 2191 * group for maximum safety. 2192 */ 2193 if (pr->ps_session != p->p_p->ps_session) { 2194 error = EPERM; 2195 goto fail; 2196 } 2197 2198 if ((pr->ps_flags & PS_EXITING) != 0) { 2199 error = ESRCH; 2200 goto fail; 2201 } 2202 } else /* if (pgid < 0) */ { 2203 pgrp = pgfind(-pgid); 2204 if (pgrp == NULL) { 2205 error = ESRCH; 2206 goto fail; 2207 } 2208 2209 /* 2210 * Policy - Don't allow a process to FSETOWN a process 2211 * in another session. 2212 * 2213 * Remove this test to allow maximum flexibility or 2214 * restrict FSETOWN to the current process or process 2215 * group for maximum safety. 2216 */ 2217 if (pgrp->pg_session != p->p_p->ps_session) { 2218 error = EPERM; 2219 goto fail; 2220 } 2221 } 2222 2223 if (pgid > 0) { 2224 sigio->sio_proc = pr; 2225 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2226 } else { 2227 sigio->sio_pgrp = pgrp; 2228 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2229 } 2230 2231 sigio_unlink(sir, &rmlist); 2232 sir->sir_sigio = sigio; 2233 2234 mtx_leave(&sigio_lock); 2235 KERNEL_UNLOCK(); 2236 2237 sigio_del(&rmlist); 2238 2239 return (0); 2240 2241 fail: 2242 mtx_leave(&sigio_lock); 2243 KERNEL_UNLOCK(); 2244 2245 crfree(sigio->sio_ucred); 2246 free(sigio, M_SIGIO, sizeof(*sigio)); 2247 2248 return (error); 2249 } 2250 2251 pid_t 2252 sigio_getown(struct sigio_ref *sir) 2253 { 2254 struct sigio *sigio; 2255 pid_t pgid = 0; 2256 2257 mtx_enter(&sigio_lock); 2258 sigio = sir->sir_sigio; 2259 if (sigio != NULL) 2260 pgid = sigio->sio_pgid; 2261 mtx_leave(&sigio_lock); 2262 2263 return (pgid); 2264 } 2265 2266 void 2267 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2268 { 2269 struct sigiolst rmlist; 2270 struct sigio *newsigio, *sigio; 2271 2272 sigio_free(dst); 2273 2274 if (src->sir_sigio == NULL) 2275 return; 2276 2277 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2278 LIST_INIT(&rmlist); 2279 2280 mtx_enter(&sigio_lock); 2281 2282 sigio = src->sir_sigio; 2283 if (sigio == NULL) { 2284 mtx_leave(&sigio_lock); 2285 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2286 return; 2287 } 2288 2289 newsigio->sio_pgid = sigio->sio_pgid; 2290 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2291 newsigio->sio_myref = dst; 2292 if (newsigio->sio_pgid > 0) { 2293 newsigio->sio_proc = sigio->sio_proc; 2294 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2295 sio_pgsigio); 2296 } else { 2297 newsigio->sio_pgrp = sigio->sio_pgrp; 2298 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2299 sio_pgsigio); 2300 } 2301 2302 sigio_unlink(dst, &rmlist); 2303 dst->sir_sigio = newsigio; 2304 2305 mtx_leave(&sigio_lock); 2306 2307 sigio_del(&rmlist); 2308 } 2309