1 /* $OpenBSD: kern_sig.c,v 1.322 2024/02/25 00:07:13 deraadt Exp $ */ 2 /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Theo de Raadt. All rights reserved. 6 * Copyright (c) 1982, 1986, 1989, 1991, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 */ 40 41 #include <sys/param.h> 42 #include <sys/signalvar.h> 43 #include <sys/queue.h> 44 #include <sys/namei.h> 45 #include <sys/vnode.h> 46 #include <sys/event.h> 47 #include <sys/proc.h> 48 #include <sys/systm.h> 49 #include <sys/acct.h> 50 #include <sys/fcntl.h> 51 #include <sys/filedesc.h> 52 #include <sys/wait.h> 53 #include <sys/ktrace.h> 54 #include <sys/stat.h> 55 #include <sys/malloc.h> 56 #include <sys/pool.h> 57 #include <sys/sched.h> 58 #include <sys/user.h> 59 #include <sys/syslog.h> 60 #include <sys/ttycom.h> 61 #include <sys/pledge.h> 62 #include <sys/witness.h> 63 #include <sys/exec_elf.h> 64 65 #include <sys/mount.h> 66 #include <sys/syscallargs.h> 67 68 #include <uvm/uvm_extern.h> 69 #include <machine/tcb.h> 70 71 int nosuidcoredump = 1; 72 73 int filt_sigattach(struct knote *kn); 74 void filt_sigdetach(struct knote *kn); 75 int filt_signal(struct knote *kn, long hint); 76 77 const struct filterops sig_filtops = { 78 .f_flags = 0, 79 .f_attach = filt_sigattach, 80 .f_detach = filt_sigdetach, 81 .f_event = filt_signal, 82 }; 83 84 /* 85 * The array below categorizes the signals and their default actions. 86 */ 87 const int sigprop[NSIG] = { 88 0, /* unused */ 89 SA_KILL, /* SIGHUP */ 90 SA_KILL, /* SIGINT */ 91 SA_KILL|SA_CORE, /* SIGQUIT */ 92 SA_KILL|SA_CORE, /* SIGILL */ 93 SA_KILL|SA_CORE, /* SIGTRAP */ 94 SA_KILL|SA_CORE, /* SIGABRT */ 95 SA_KILL|SA_CORE, /* SIGEMT */ 96 SA_KILL|SA_CORE, /* SIGFPE */ 97 SA_KILL, /* SIGKILL */ 98 SA_KILL|SA_CORE, /* SIGBUS */ 99 SA_KILL|SA_CORE, /* SIGSEGV */ 100 SA_KILL|SA_CORE, /* SIGSYS */ 101 SA_KILL, /* SIGPIPE */ 102 SA_KILL, /* SIGALRM */ 103 SA_KILL, /* SIGTERM */ 104 SA_IGNORE, /* SIGURG */ 105 SA_STOP, /* SIGSTOP */ 106 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 107 SA_IGNORE|SA_CONT, /* SIGCONT */ 108 SA_IGNORE, /* SIGCHLD */ 109 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 110 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 111 SA_IGNORE, /* SIGIO */ 112 SA_KILL, /* SIGXCPU */ 113 SA_KILL, /* SIGXFSZ */ 114 SA_KILL, /* SIGVTALRM */ 115 SA_KILL, /* SIGPROF */ 116 SA_IGNORE, /* SIGWINCH */ 117 SA_IGNORE, /* SIGINFO */ 118 SA_KILL, /* SIGUSR1 */ 119 SA_KILL, /* SIGUSR2 */ 120 SA_IGNORE, /* SIGTHR */ 121 }; 122 123 #define CONTSIGMASK (sigmask(SIGCONT)) 124 #define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 125 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 126 127 void setsigvec(struct proc *, int, struct sigaction *); 128 129 void proc_stop(struct proc *p, int); 130 void proc_stop_sweep(void *); 131 void *proc_stop_si; 132 133 void setsigctx(struct proc *, int, struct sigctx *); 134 void postsig_done(struct proc *, int, sigset_t, int); 135 void postsig(struct proc *, int, struct sigctx *); 136 int cansignal(struct proc *, struct process *, int); 137 138 struct pool sigacts_pool; /* memory pool for sigacts structures */ 139 140 void sigio_del(struct sigiolst *); 141 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 142 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 143 144 /* 145 * Can thread p, send the signal signum to process qr? 146 */ 147 int 148 cansignal(struct proc *p, struct process *qr, int signum) 149 { 150 struct process *pr = p->p_p; 151 struct ucred *uc = p->p_ucred; 152 struct ucred *quc = qr->ps_ucred; 153 154 if (uc->cr_uid == 0) 155 return (1); /* root can always signal */ 156 157 if (pr == qr) 158 return (1); /* process can always signal itself */ 159 160 /* optimization: if the same creds then the tests below will pass */ 161 if (uc == quc) 162 return (1); 163 164 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 165 return (1); /* SIGCONT in session */ 166 167 /* 168 * Using kill(), only certain signals can be sent to setugid 169 * child processes 170 */ 171 if (qr->ps_flags & PS_SUGID) { 172 switch (signum) { 173 case 0: 174 case SIGKILL: 175 case SIGINT: 176 case SIGTERM: 177 case SIGALRM: 178 case SIGSTOP: 179 case SIGTTIN: 180 case SIGTTOU: 181 case SIGTSTP: 182 case SIGHUP: 183 case SIGUSR1: 184 case SIGUSR2: 185 if (uc->cr_ruid == quc->cr_ruid || 186 uc->cr_uid == quc->cr_ruid) 187 return (1); 188 } 189 return (0); 190 } 191 192 if (uc->cr_ruid == quc->cr_ruid || 193 uc->cr_ruid == quc->cr_svuid || 194 uc->cr_uid == quc->cr_ruid || 195 uc->cr_uid == quc->cr_svuid) 196 return (1); 197 return (0); 198 } 199 200 /* 201 * Initialize signal-related data structures. 202 */ 203 void 204 signal_init(void) 205 { 206 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 207 NULL); 208 if (proc_stop_si == NULL) 209 panic("signal_init failed to register softintr"); 210 211 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 212 PR_WAITOK, "sigapl", NULL); 213 } 214 215 /* 216 * Initialize a new sigaltstack structure. 217 */ 218 void 219 sigstkinit(struct sigaltstack *ss) 220 { 221 ss->ss_flags = SS_DISABLE; 222 ss->ss_size = 0; 223 ss->ss_sp = NULL; 224 } 225 226 /* 227 * Create an initial sigacts structure, using the same signal state 228 * as pr. 229 */ 230 struct sigacts * 231 sigactsinit(struct process *pr) 232 { 233 struct sigacts *ps; 234 235 ps = pool_get(&sigacts_pool, PR_WAITOK); 236 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 237 return (ps); 238 } 239 240 /* 241 * Release a sigacts structure. 242 */ 243 void 244 sigactsfree(struct sigacts *ps) 245 { 246 pool_put(&sigacts_pool, ps); 247 } 248 249 int 250 sys_sigaction(struct proc *p, void *v, register_t *retval) 251 { 252 struct sys_sigaction_args /* { 253 syscallarg(int) signum; 254 syscallarg(const struct sigaction *) nsa; 255 syscallarg(struct sigaction *) osa; 256 } */ *uap = v; 257 struct sigaction vec; 258 #ifdef KTRACE 259 struct sigaction ovec; 260 #endif 261 struct sigaction *sa; 262 const struct sigaction *nsa; 263 struct sigaction *osa; 264 struct sigacts *ps = p->p_p->ps_sigacts; 265 int signum; 266 int bit, error; 267 268 signum = SCARG(uap, signum); 269 nsa = SCARG(uap, nsa); 270 osa = SCARG(uap, osa); 271 272 if (signum <= 0 || signum >= NSIG || 273 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 274 return (EINVAL); 275 sa = &vec; 276 if (osa) { 277 mtx_enter(&p->p_p->ps_mtx); 278 sa->sa_handler = ps->ps_sigact[signum]; 279 sa->sa_mask = ps->ps_catchmask[signum]; 280 bit = sigmask(signum); 281 sa->sa_flags = 0; 282 if ((ps->ps_sigonstack & bit) != 0) 283 sa->sa_flags |= SA_ONSTACK; 284 if ((ps->ps_sigintr & bit) == 0) 285 sa->sa_flags |= SA_RESTART; 286 if ((ps->ps_sigreset & bit) != 0) 287 sa->sa_flags |= SA_RESETHAND; 288 if ((ps->ps_siginfo & bit) != 0) 289 sa->sa_flags |= SA_SIGINFO; 290 if (signum == SIGCHLD) { 291 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 292 sa->sa_flags |= SA_NOCLDSTOP; 293 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 294 sa->sa_flags |= SA_NOCLDWAIT; 295 } 296 mtx_leave(&p->p_p->ps_mtx); 297 if ((sa->sa_mask & bit) == 0) 298 sa->sa_flags |= SA_NODEFER; 299 sa->sa_mask &= ~bit; 300 error = copyout(sa, osa, sizeof (vec)); 301 if (error) 302 return (error); 303 #ifdef KTRACE 304 if (KTRPOINT(p, KTR_STRUCT)) 305 ovec = vec; 306 #endif 307 } 308 if (nsa) { 309 error = copyin(nsa, sa, sizeof (vec)); 310 if (error) 311 return (error); 312 #ifdef KTRACE 313 if (KTRPOINT(p, KTR_STRUCT)) 314 ktrsigaction(p, sa); 315 #endif 316 setsigvec(p, signum, sa); 317 } 318 #ifdef KTRACE 319 if (osa && KTRPOINT(p, KTR_STRUCT)) 320 ktrsigaction(p, &ovec); 321 #endif 322 return (0); 323 } 324 325 void 326 setsigvec(struct proc *p, int signum, struct sigaction *sa) 327 { 328 struct sigacts *ps = p->p_p->ps_sigacts; 329 int bit; 330 331 bit = sigmask(signum); 332 333 mtx_enter(&p->p_p->ps_mtx); 334 ps->ps_sigact[signum] = sa->sa_handler; 335 if ((sa->sa_flags & SA_NODEFER) == 0) 336 sa->sa_mask |= sigmask(signum); 337 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 338 if (signum == SIGCHLD) { 339 if (sa->sa_flags & SA_NOCLDSTOP) 340 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 341 else 342 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 343 /* 344 * If the SA_NOCLDWAIT flag is set or the handler 345 * is SIG_IGN we reparent the dying child to PID 1 346 * (init) which will reap the zombie. Because we use 347 * init to do our dirty work we never set SAS_NOCLDWAIT 348 * for PID 1. 349 * XXX exit1 rework means this is unnecessary? 350 */ 351 if (initprocess->ps_sigacts != ps && 352 ((sa->sa_flags & SA_NOCLDWAIT) || 353 sa->sa_handler == SIG_IGN)) 354 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 355 else 356 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 357 } 358 if ((sa->sa_flags & SA_RESETHAND) != 0) 359 ps->ps_sigreset |= bit; 360 else 361 ps->ps_sigreset &= ~bit; 362 if ((sa->sa_flags & SA_SIGINFO) != 0) 363 ps->ps_siginfo |= bit; 364 else 365 ps->ps_siginfo &= ~bit; 366 if ((sa->sa_flags & SA_RESTART) == 0) 367 ps->ps_sigintr |= bit; 368 else 369 ps->ps_sigintr &= ~bit; 370 if ((sa->sa_flags & SA_ONSTACK) != 0) 371 ps->ps_sigonstack |= bit; 372 else 373 ps->ps_sigonstack &= ~bit; 374 /* 375 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 376 * and for signals set to SIG_DFL where the default is to ignore. 377 * However, don't put SIGCONT in ps_sigignore, 378 * as we have to restart the process. 379 */ 380 if (sa->sa_handler == SIG_IGN || 381 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 382 atomic_clearbits_int(&p->p_siglist, bit); 383 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 384 if (signum != SIGCONT) 385 ps->ps_sigignore |= bit; /* easier in psignal */ 386 ps->ps_sigcatch &= ~bit; 387 } else { 388 ps->ps_sigignore &= ~bit; 389 if (sa->sa_handler == SIG_DFL) 390 ps->ps_sigcatch &= ~bit; 391 else 392 ps->ps_sigcatch |= bit; 393 } 394 mtx_leave(&p->p_p->ps_mtx); 395 } 396 397 /* 398 * Initialize signal state for process 0; 399 * set to ignore signals that are ignored by default. 400 */ 401 void 402 siginit(struct sigacts *ps) 403 { 404 int i; 405 406 for (i = 0; i < NSIG; i++) 407 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 408 ps->ps_sigignore |= sigmask(i); 409 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 410 } 411 412 /* 413 * Reset signals for an exec by the specified thread. 414 */ 415 void 416 execsigs(struct proc *p) 417 { 418 struct sigacts *ps; 419 int nc, mask; 420 421 ps = p->p_p->ps_sigacts; 422 mtx_enter(&p->p_p->ps_mtx); 423 424 /* 425 * Reset caught signals. Held signals remain held 426 * through p_sigmask (unless they were caught, 427 * and are now ignored by default). 428 */ 429 while (ps->ps_sigcatch) { 430 nc = ffs((long)ps->ps_sigcatch); 431 mask = sigmask(nc); 432 ps->ps_sigcatch &= ~mask; 433 if (sigprop[nc] & SA_IGNORE) { 434 if (nc != SIGCONT) 435 ps->ps_sigignore |= mask; 436 atomic_clearbits_int(&p->p_siglist, mask); 437 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 438 } 439 ps->ps_sigact[nc] = SIG_DFL; 440 } 441 /* 442 * Reset stack state to the user stack. 443 * Clear set of signals caught on the signal stack. 444 */ 445 sigstkinit(&p->p_sigstk); 446 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 447 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 448 ps->ps_sigact[SIGCHLD] = SIG_DFL; 449 mtx_leave(&p->p_p->ps_mtx); 450 } 451 452 /* 453 * Manipulate signal mask. 454 * Note that we receive new mask, not pointer, 455 * and return old mask as return value; 456 * the library stub does the rest. 457 */ 458 int 459 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 460 { 461 struct sys_sigprocmask_args /* { 462 syscallarg(int) how; 463 syscallarg(sigset_t) mask; 464 } */ *uap = v; 465 int error = 0; 466 sigset_t mask; 467 468 KASSERT(p == curproc); 469 470 *retval = p->p_sigmask; 471 mask = SCARG(uap, mask) &~ sigcantmask; 472 473 switch (SCARG(uap, how)) { 474 case SIG_BLOCK: 475 atomic_setbits_int(&p->p_sigmask, mask); 476 break; 477 case SIG_UNBLOCK: 478 atomic_clearbits_int(&p->p_sigmask, mask); 479 break; 480 case SIG_SETMASK: 481 p->p_sigmask = mask; 482 break; 483 default: 484 error = EINVAL; 485 break; 486 } 487 return (error); 488 } 489 490 int 491 sys_sigpending(struct proc *p, void *v, register_t *retval) 492 { 493 *retval = p->p_siglist | p->p_p->ps_siglist; 494 return (0); 495 } 496 497 /* 498 * Temporarily replace calling proc's signal mask for the duration of a 499 * system call. Original signal mask will be restored by userret(). 500 */ 501 void 502 dosigsuspend(struct proc *p, sigset_t newmask) 503 { 504 KASSERT(p == curproc); 505 506 p->p_oldmask = p->p_sigmask; 507 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 508 p->p_sigmask = newmask; 509 } 510 511 /* 512 * Suspend thread until signal, providing mask to be set 513 * in the meantime. Note nonstandard calling convention: 514 * libc stub passes mask, not pointer, to save a copyin. 515 */ 516 int 517 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 518 { 519 struct sys_sigsuspend_args /* { 520 syscallarg(int) mask; 521 } */ *uap = v; 522 523 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 524 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 525 continue; 526 /* always return EINTR rather than ERESTART... */ 527 return (EINTR); 528 } 529 530 int 531 sigonstack(size_t stack) 532 { 533 const struct sigaltstack *ss = &curproc->p_sigstk; 534 535 return (ss->ss_flags & SS_DISABLE ? 0 : 536 (stack - (size_t)ss->ss_sp < ss->ss_size)); 537 } 538 539 int 540 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 541 { 542 struct sys_sigaltstack_args /* { 543 syscallarg(const struct sigaltstack *) nss; 544 syscallarg(struct sigaltstack *) oss; 545 } */ *uap = v; 546 struct sigaltstack ss; 547 const struct sigaltstack *nss; 548 struct sigaltstack *oss; 549 int onstack = sigonstack(PROC_STACK(p)); 550 int error; 551 552 nss = SCARG(uap, nss); 553 oss = SCARG(uap, oss); 554 555 if (oss != NULL) { 556 ss = p->p_sigstk; 557 if (onstack) 558 ss.ss_flags |= SS_ONSTACK; 559 if ((error = copyout(&ss, oss, sizeof(ss)))) 560 return (error); 561 } 562 if (nss == NULL) 563 return (0); 564 error = copyin(nss, &ss, sizeof(ss)); 565 if (error) 566 return (error); 567 if (onstack) 568 return (EPERM); 569 if (ss.ss_flags & ~SS_DISABLE) 570 return (EINVAL); 571 if (ss.ss_flags & SS_DISABLE) { 572 p->p_sigstk.ss_flags = ss.ss_flags; 573 return (0); 574 } 575 if (ss.ss_size < MINSIGSTKSZ) 576 return (ENOMEM); 577 578 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 579 if (error) 580 return (error); 581 582 p->p_sigstk = ss; 583 return (0); 584 } 585 586 int 587 sys_kill(struct proc *cp, void *v, register_t *retval) 588 { 589 struct sys_kill_args /* { 590 syscallarg(int) pid; 591 syscallarg(int) signum; 592 } */ *uap = v; 593 struct process *pr; 594 int pid = SCARG(uap, pid); 595 int signum = SCARG(uap, signum); 596 int error; 597 int zombie = 0; 598 599 if ((error = pledge_kill(cp, pid)) != 0) 600 return (error); 601 if (((u_int)signum) >= NSIG) 602 return (EINVAL); 603 if (pid > 0) { 604 if ((pr = prfind(pid)) == NULL) { 605 if ((pr = zombiefind(pid)) == NULL) 606 return (ESRCH); 607 else 608 zombie = 1; 609 } 610 if (!cansignal(cp, pr, signum)) 611 return (EPERM); 612 613 /* kill single process */ 614 if (signum && !zombie) 615 prsignal(pr, signum); 616 return (0); 617 } 618 switch (pid) { 619 case -1: /* broadcast signal */ 620 return (killpg1(cp, signum, 0, 1)); 621 case 0: /* signal own process group */ 622 return (killpg1(cp, signum, 0, 0)); 623 default: /* negative explicit process group */ 624 return (killpg1(cp, signum, -pid, 0)); 625 } 626 } 627 628 int 629 sys_thrkill(struct proc *cp, void *v, register_t *retval) 630 { 631 struct sys_thrkill_args /* { 632 syscallarg(pid_t) tid; 633 syscallarg(int) signum; 634 syscallarg(void *) tcb; 635 } */ *uap = v; 636 struct proc *p; 637 int tid = SCARG(uap, tid); 638 int signum = SCARG(uap, signum); 639 void *tcb; 640 641 if (((u_int)signum) >= NSIG) 642 return (EINVAL); 643 644 p = tid ? tfind_user(tid, cp->p_p) : cp; 645 if (p == NULL) 646 return (ESRCH); 647 648 /* optionally require the target thread to have the given tcb addr */ 649 tcb = SCARG(uap, tcb); 650 if (tcb != NULL && tcb != TCB_GET(p)) 651 return (ESRCH); 652 653 if (signum) 654 ptsignal(p, signum, STHREAD); 655 return (0); 656 } 657 658 /* 659 * Common code for kill process group/broadcast kill. 660 * cp is calling process. 661 */ 662 int 663 killpg1(struct proc *cp, int signum, int pgid, int all) 664 { 665 struct process *pr; 666 struct pgrp *pgrp; 667 int nfound = 0; 668 669 if (all) { 670 /* 671 * broadcast 672 */ 673 LIST_FOREACH(pr, &allprocess, ps_list) { 674 if (pr->ps_pid <= 1 || 675 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 676 pr == cp->p_p || !cansignal(cp, pr, signum)) 677 continue; 678 nfound++; 679 if (signum) 680 prsignal(pr, signum); 681 } 682 } else { 683 if (pgid == 0) 684 /* 685 * zero pgid means send to my process group. 686 */ 687 pgrp = cp->p_p->ps_pgrp; 688 else { 689 pgrp = pgfind(pgid); 690 if (pgrp == NULL) 691 return (ESRCH); 692 } 693 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 694 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 695 !cansignal(cp, pr, signum)) 696 continue; 697 nfound++; 698 if (signum) 699 prsignal(pr, signum); 700 } 701 } 702 return (nfound ? 0 : ESRCH); 703 } 704 705 #define CANDELIVER(uid, euid, pr) \ 706 (euid == 0 || \ 707 (uid) == (pr)->ps_ucred->cr_ruid || \ 708 (uid) == (pr)->ps_ucred->cr_svuid || \ 709 (uid) == (pr)->ps_ucred->cr_uid || \ 710 (euid) == (pr)->ps_ucred->cr_ruid || \ 711 (euid) == (pr)->ps_ucred->cr_svuid || \ 712 (euid) == (pr)->ps_ucred->cr_uid) 713 714 #define CANSIGIO(cr, pr) \ 715 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 716 717 /* 718 * Send a signal to a process group. If checktty is 1, 719 * limit to members which have a controlling terminal. 720 */ 721 void 722 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 723 { 724 struct process *pr; 725 726 if (pgrp) 727 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 728 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 729 prsignal(pr, signum); 730 } 731 732 /* 733 * Send a SIGIO or SIGURG signal to a process or process group using stored 734 * credentials rather than those of the current process. 735 */ 736 void 737 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 738 { 739 struct process *pr; 740 struct sigio *sigio; 741 742 if (sir->sir_sigio == NULL) 743 return; 744 745 KERNEL_LOCK(); 746 mtx_enter(&sigio_lock); 747 sigio = sir->sir_sigio; 748 if (sigio == NULL) 749 goto out; 750 if (sigio->sio_pgid > 0) { 751 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 752 prsignal(sigio->sio_proc, sig); 753 } else if (sigio->sio_pgid < 0) { 754 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 755 if (CANSIGIO(sigio->sio_ucred, pr) && 756 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 757 prsignal(pr, sig); 758 } 759 } 760 out: 761 mtx_leave(&sigio_lock); 762 KERNEL_UNLOCK(); 763 } 764 765 /* 766 * Recalculate the signal mask and reset the signal disposition after 767 * usermode frame for delivery is formed. 768 */ 769 void 770 postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 771 { 772 p->p_ru.ru_nsignals++; 773 atomic_setbits_int(&p->p_sigmask, catchmask); 774 if (reset != 0) { 775 sigset_t mask = sigmask(signum); 776 struct sigacts *ps = p->p_p->ps_sigacts; 777 778 mtx_enter(&p->p_p->ps_mtx); 779 ps->ps_sigcatch &= ~mask; 780 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 781 ps->ps_sigignore |= mask; 782 ps->ps_sigact[signum] = SIG_DFL; 783 mtx_leave(&p->p_p->ps_mtx); 784 } 785 } 786 787 /* 788 * Send a signal caused by a trap to the current thread 789 * If it will be caught immediately, deliver it with correct code. 790 * Otherwise, post it normally. 791 */ 792 void 793 trapsignal(struct proc *p, int signum, u_long trapno, int code, 794 union sigval sigval) 795 { 796 struct process *pr = p->p_p; 797 struct sigctx ctx; 798 int mask; 799 800 switch (signum) { 801 case SIGILL: 802 if (code == ILL_BTCFI) { 803 pr->ps_acflag |= ABTCFI; 804 break; 805 } 806 /* FALLTHROUGH */ 807 case SIGBUS: 808 case SIGSEGV: 809 pr->ps_acflag |= ATRAP; 810 break; 811 } 812 813 mask = sigmask(signum); 814 setsigctx(p, signum, &ctx); 815 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 816 (p->p_sigmask & mask) == 0) { 817 siginfo_t si; 818 819 initsiginfo(&si, signum, trapno, code, sigval); 820 #ifdef KTRACE 821 if (KTRPOINT(p, KTR_PSIG)) { 822 ktrpsig(p, signum, ctx.sig_action, 823 p->p_sigmask, code, &si); 824 } 825 #endif 826 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 827 ctx.sig_info, ctx.sig_onstack)) { 828 KERNEL_LOCK(); 829 sigexit(p, SIGILL); 830 /* NOTREACHED */ 831 } 832 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 833 } else { 834 p->p_sisig = signum; 835 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 836 p->p_sicode = code; 837 p->p_sigval = sigval; 838 839 /* 840 * If traced, stop if signal is masked, and stay stopped 841 * until released by the debugger. If our parent process 842 * is waiting for us, don't hang as we could deadlock. 843 */ 844 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 845 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 846 int s; 847 848 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 849 pr->ps_xsig = signum; 850 851 SCHED_LOCK(s); 852 proc_stop(p, 1); 853 SCHED_UNLOCK(s); 854 855 signum = pr->ps_xsig; 856 single_thread_clear(p, 0); 857 858 /* 859 * If we are no longer being traced, or the parent 860 * didn't give us a signal, skip sending the signal. 861 */ 862 if ((pr->ps_flags & PS_TRACED) == 0 || 863 signum == 0) 864 return; 865 866 /* update signal info */ 867 p->p_sisig = signum; 868 mask = sigmask(signum); 869 } 870 871 /* 872 * Signals like SIGBUS and SIGSEGV should not, when 873 * generated by the kernel, be ignorable or blockable. 874 * If it is and we're not being traced, then just kill 875 * the process. 876 * After vfs_shutdown(9), init(8) cannot receive signals 877 * because new code pages of the signal handler cannot be 878 * mapped from halted storage. init(8) may not die or the 879 * kernel panics. Better loop between signal handler and 880 * page fault trap until the machine is halted. 881 */ 882 if ((pr->ps_flags & PS_TRACED) == 0 && 883 (sigprop[signum] & SA_KILL) && 884 ((p->p_sigmask & mask) || ctx.sig_ignore) && 885 pr->ps_pid != 1) { 886 KERNEL_LOCK(); 887 sigexit(p, signum); 888 /* NOTREACHED */ 889 } 890 KERNEL_LOCK(); 891 ptsignal(p, signum, STHREAD); 892 KERNEL_UNLOCK(); 893 } 894 } 895 896 /* 897 * Send the signal to the process. If the signal has an action, the action 898 * is usually performed by the target process rather than the caller; we add 899 * the signal to the set of pending signals for the process. 900 * 901 * Exceptions: 902 * o When a stop signal is sent to a sleeping process that takes the 903 * default action, the process is stopped without awakening it. 904 * o SIGCONT restarts stopped processes (or puts them back to sleep) 905 * regardless of the signal action (eg, blocked or ignored). 906 * 907 * Other ignored signals are discarded immediately. 908 */ 909 void 910 psignal(struct proc *p, int signum) 911 { 912 ptsignal(p, signum, SPROCESS); 913 } 914 915 /* 916 * type = SPROCESS process signal, can be diverted (sigwait()) 917 * type = STHREAD thread signal, but should be propagated if unhandled 918 * type = SPROPAGATED propagated to this thread, so don't propagate again 919 */ 920 void 921 ptsignal(struct proc *p, int signum, enum signal_type type) 922 { 923 int s, prop; 924 sig_t action; 925 int mask; 926 int *siglist; 927 struct process *pr = p->p_p; 928 struct proc *q; 929 int wakeparent = 0; 930 931 KERNEL_ASSERT_LOCKED(); 932 933 #ifdef DIAGNOSTIC 934 if ((u_int)signum >= NSIG || signum == 0) 935 panic("psignal signal number"); 936 #endif 937 938 /* Ignore signal if the target process is exiting */ 939 if (pr->ps_flags & PS_EXITING) 940 return; 941 942 mask = sigmask(signum); 943 944 if (type == SPROCESS) { 945 /* Accept SIGKILL to coredumping processes */ 946 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 947 atomic_setbits_int(&pr->ps_siglist, mask); 948 return; 949 } 950 951 /* 952 * If the current thread can process the signal 953 * immediately (it's unblocked) then have it take it. 954 */ 955 q = curproc; 956 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 957 (q->p_sigmask & mask) == 0) 958 p = q; 959 else { 960 /* 961 * A process-wide signal can be diverted to a 962 * different thread that's in sigwait() for this 963 * signal. If there isn't such a thread, then 964 * pick a thread that doesn't have it blocked so 965 * that the stop/kill consideration isn't 966 * delayed. Otherwise, mark it pending on the 967 * main thread. 968 */ 969 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 970 /* ignore exiting threads */ 971 if (q->p_flag & P_WEXIT) 972 continue; 973 974 /* skip threads that have the signal blocked */ 975 if ((q->p_sigmask & mask) != 0) 976 continue; 977 978 /* okay, could send to this thread */ 979 p = q; 980 981 /* 982 * sigsuspend, sigwait, ppoll/pselect, etc? 983 * Definitely go to this thread, as it's 984 * already blocked in the kernel. 985 */ 986 if (q->p_flag & P_SIGSUSPEND) 987 break; 988 } 989 } 990 } 991 992 if (type != SPROPAGATED) 993 knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); 994 995 prop = sigprop[signum]; 996 997 /* 998 * If proc is traced, always give parent a chance. 999 */ 1000 if (pr->ps_flags & PS_TRACED) { 1001 action = SIG_DFL; 1002 } else { 1003 sigset_t sigcatch, sigignore; 1004 1005 /* 1006 * If the signal is being ignored, 1007 * then we forget about it immediately. 1008 * (Note: we don't set SIGCONT in ps_sigignore, 1009 * and if it is set to SIG_IGN, 1010 * action will be SIG_DFL here.) 1011 */ 1012 mtx_enter(&pr->ps_mtx); 1013 sigignore = pr->ps_sigacts->ps_sigignore; 1014 sigcatch = pr->ps_sigacts->ps_sigcatch; 1015 mtx_leave(&pr->ps_mtx); 1016 1017 if (sigignore & mask) 1018 return; 1019 if (p->p_sigmask & mask) { 1020 action = SIG_HOLD; 1021 } else if (sigcatch & mask) { 1022 action = SIG_CATCH; 1023 } else { 1024 action = SIG_DFL; 1025 1026 if (prop & SA_KILL && pr->ps_nice > NZERO) 1027 pr->ps_nice = NZERO; 1028 1029 /* 1030 * If sending a tty stop signal to a member of an 1031 * orphaned process group, discard the signal here if 1032 * the action is default; don't stop the process below 1033 * if sleeping, and don't clear any pending SIGCONT. 1034 */ 1035 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1036 return; 1037 } 1038 } 1039 /* 1040 * If delivered to process, mark as pending there. Continue and stop 1041 * signals will be propagated to all threads. So they are always 1042 * marked at thread level. 1043 */ 1044 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1045 if (prop & SA_CONT) { 1046 siglist = &p->p_siglist; 1047 atomic_clearbits_int(siglist, STOPSIGMASK); 1048 } 1049 if (prop & SA_STOP) { 1050 siglist = &p->p_siglist; 1051 atomic_clearbits_int(siglist, CONTSIGMASK); 1052 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1053 } 1054 1055 /* 1056 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1057 */ 1058 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1059 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1060 if (q != p) 1061 ptsignal(q, signum, SPROPAGATED); 1062 1063 /* 1064 * Defer further processing for signals which are held, 1065 * except that stopped processes must be continued by SIGCONT. 1066 */ 1067 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || 1068 p->p_stat != SSTOP)) { 1069 atomic_setbits_int(siglist, mask); 1070 return; 1071 } 1072 1073 SCHED_LOCK(s); 1074 1075 switch (p->p_stat) { 1076 1077 case SSLEEP: 1078 /* 1079 * If process is sleeping uninterruptibly 1080 * we can't interrupt the sleep... the signal will 1081 * be noticed when the process returns through 1082 * trap() or syscall(). 1083 */ 1084 if ((p->p_flag & P_SINTR) == 0) 1085 goto out; 1086 /* 1087 * Process is sleeping and traced... make it runnable 1088 * so it can discover the signal in cursig() and stop 1089 * for the parent. 1090 */ 1091 if (pr->ps_flags & PS_TRACED) 1092 goto run; 1093 /* 1094 * If SIGCONT is default (or ignored) and process is 1095 * asleep, we are finished; the process should not 1096 * be awakened. 1097 */ 1098 if ((prop & SA_CONT) && action == SIG_DFL) { 1099 mask = 0; 1100 goto out; 1101 } 1102 /* 1103 * When a sleeping process receives a stop 1104 * signal, process immediately if possible. 1105 */ 1106 if ((prop & SA_STOP) && action == SIG_DFL) { 1107 /* 1108 * If a child holding parent blocked, 1109 * stopping could cause deadlock. 1110 */ 1111 if (pr->ps_flags & PS_PPWAIT) 1112 goto out; 1113 mask = 0; 1114 pr->ps_xsig = signum; 1115 proc_stop(p, 0); 1116 goto out; 1117 } 1118 /* 1119 * All other (caught or default) signals 1120 * cause the process to run. 1121 */ 1122 goto runfast; 1123 /* NOTREACHED */ 1124 1125 case SSTOP: 1126 /* 1127 * If traced process is already stopped, 1128 * then no further action is necessary. 1129 */ 1130 if (pr->ps_flags & PS_TRACED) 1131 goto out; 1132 1133 /* 1134 * Kill signal always sets processes running. 1135 */ 1136 if (signum == SIGKILL) { 1137 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1138 goto runfast; 1139 } 1140 1141 if (prop & SA_CONT) { 1142 /* 1143 * If SIGCONT is default (or ignored), we continue the 1144 * process but don't leave the signal in p_siglist, as 1145 * it has no further action. If SIGCONT is held, we 1146 * continue the process and leave the signal in 1147 * p_siglist. If the process catches SIGCONT, let it 1148 * handle the signal itself. If it isn't waiting on 1149 * an event, then it goes back to run state. 1150 * Otherwise, process goes back to sleep state. 1151 */ 1152 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1153 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1154 wakeparent = 1; 1155 if (action == SIG_DFL) 1156 atomic_clearbits_int(siglist, mask); 1157 if (action == SIG_CATCH) 1158 goto runfast; 1159 if (p->p_wchan == NULL) 1160 goto run; 1161 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1162 p->p_stat = SSLEEP; 1163 goto out; 1164 } 1165 1166 if (prop & SA_STOP) { 1167 /* 1168 * Already stopped, don't need to stop again. 1169 * (If we did the shell could get confused.) 1170 */ 1171 mask = 0; 1172 goto out; 1173 } 1174 1175 /* 1176 * If process is sleeping interruptibly, then simulate a 1177 * wakeup so that when it is continued, it will be made 1178 * runnable and can look at the signal. But don't make 1179 * the process runnable, leave it stopped. 1180 */ 1181 if (p->p_flag & P_SINTR) 1182 unsleep(p); 1183 goto out; 1184 1185 case SONPROC: 1186 /* set siglist before issuing the ast */ 1187 atomic_setbits_int(siglist, mask); 1188 mask = 0; 1189 signotify(p); 1190 /* FALLTHROUGH */ 1191 default: 1192 /* 1193 * SRUN, SIDL, SDEAD do nothing with the signal, 1194 * other than kicking ourselves if we are running. 1195 * It will either never be noticed, or noticed very soon. 1196 */ 1197 goto out; 1198 } 1199 /* NOTREACHED */ 1200 1201 runfast: 1202 /* 1203 * Raise priority to at least PUSER. 1204 */ 1205 if (p->p_usrpri > PUSER) 1206 p->p_usrpri = PUSER; 1207 run: 1208 setrunnable(p); 1209 out: 1210 /* finally adjust siglist */ 1211 if (mask) 1212 atomic_setbits_int(siglist, mask); 1213 SCHED_UNLOCK(s); 1214 if (wakeparent) 1215 wakeup(pr->ps_pptr); 1216 } 1217 1218 /* fill the signal context which should be used by postsig() and issignal() */ 1219 void 1220 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1221 { 1222 struct sigacts *ps = p->p_p->ps_sigacts; 1223 sigset_t mask; 1224 1225 mtx_enter(&p->p_p->ps_mtx); 1226 mask = sigmask(signum); 1227 sctx->sig_action = ps->ps_sigact[signum]; 1228 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1229 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1230 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1231 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1232 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1233 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1234 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1235 mtx_leave(&p->p_p->ps_mtx); 1236 } 1237 1238 /* 1239 * Determine signal that should be delivered to process p, the current 1240 * process, 0 if none. 1241 * 1242 * If the current process has received a signal (should be caught or cause 1243 * termination, should interrupt current syscall), return the signal number. 1244 * Stop signals with default action are processed immediately, then cleared; 1245 * they aren't returned. This is checked after each entry to the system for 1246 * a syscall or trap. The normal call sequence is 1247 * 1248 * while (signum = cursig(curproc, &ctx)) 1249 * postsig(signum, &ctx); 1250 * 1251 * Assumes that if the P_SINTR flag is set, we're holding both the 1252 * kernel and scheduler locks. 1253 */ 1254 int 1255 cursig(struct proc *p, struct sigctx *sctx) 1256 { 1257 struct process *pr = p->p_p; 1258 int signum, mask, prop; 1259 sigset_t ps_siglist; 1260 int s; 1261 1262 KASSERT(p == curproc); 1263 1264 for (;;) { 1265 ps_siglist = READ_ONCE(pr->ps_siglist); 1266 membar_consumer(); 1267 mask = SIGPENDING(p); 1268 if (pr->ps_flags & PS_PPWAIT) 1269 mask &= ~STOPSIGMASK; 1270 if (mask == 0) /* no signal to send */ 1271 return (0); 1272 signum = ffs((long)mask); 1273 mask = sigmask(signum); 1274 1275 /* take the signal! */ 1276 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1277 ps_siglist & ~mask) != ps_siglist) { 1278 /* lost race taking the process signal, restart */ 1279 continue; 1280 } 1281 atomic_clearbits_int(&p->p_siglist, mask); 1282 setsigctx(p, signum, sctx); 1283 1284 /* 1285 * We should see pending but ignored signals 1286 * only if PS_TRACED was on when they were posted. 1287 */ 1288 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1289 continue; 1290 1291 /* 1292 * If traced, always stop, and stay stopped until released 1293 * by the debugger. If our parent process is waiting for 1294 * us, don't hang as we could deadlock. 1295 */ 1296 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1297 signum != SIGKILL) { 1298 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1299 pr->ps_xsig = signum; 1300 1301 SCHED_LOCK(s); 1302 proc_stop(p, 1); 1303 SCHED_UNLOCK(s); 1304 1305 /* 1306 * re-take the signal before releasing 1307 * the other threads. Must check the continue 1308 * conditions below and only take the signal if 1309 * those are not true. 1310 */ 1311 signum = pr->ps_xsig; 1312 mask = sigmask(signum); 1313 setsigctx(p, signum, sctx); 1314 if (!((pr->ps_flags & PS_TRACED) == 0 || 1315 signum == 0 || 1316 (p->p_sigmask & mask) != 0)) { 1317 atomic_clearbits_int(&p->p_siglist, mask); 1318 atomic_clearbits_int(&pr->ps_siglist, mask); 1319 } 1320 1321 single_thread_clear(p, 0); 1322 1323 /* 1324 * If we are no longer being traced, or the parent 1325 * didn't give us a signal, look for more signals. 1326 */ 1327 if ((pr->ps_flags & PS_TRACED) == 0 || 1328 signum == 0) 1329 continue; 1330 1331 /* 1332 * If the new signal is being masked, look for other 1333 * signals. 1334 */ 1335 if ((p->p_sigmask & mask) != 0) 1336 continue; 1337 1338 } 1339 1340 prop = sigprop[signum]; 1341 1342 /* 1343 * Decide whether the signal should be returned. 1344 * Return the signal's number, or fall through 1345 * to clear it from the pending mask. 1346 */ 1347 switch ((long)sctx->sig_action) { 1348 case (long)SIG_DFL: 1349 /* 1350 * Don't take default actions on system processes. 1351 */ 1352 if (pr->ps_pid <= 1) { 1353 #ifdef DIAGNOSTIC 1354 /* 1355 * Are you sure you want to ignore SIGSEGV 1356 * in init? XXX 1357 */ 1358 printf("Process (pid %d) got signal" 1359 " %d\n", pr->ps_pid, signum); 1360 #endif 1361 break; /* == ignore */ 1362 } 1363 /* 1364 * If there is a pending stop signal to process 1365 * with default action, stop here, 1366 * then clear the signal. However, 1367 * if process is member of an orphaned 1368 * process group, ignore tty stop signals. 1369 */ 1370 if (prop & SA_STOP) { 1371 if (pr->ps_flags & PS_TRACED || 1372 (pr->ps_pgrp->pg_jobc == 0 && 1373 prop & SA_TTYSTOP)) 1374 break; /* == ignore */ 1375 pr->ps_xsig = signum; 1376 SCHED_LOCK(s); 1377 proc_stop(p, 1); 1378 SCHED_UNLOCK(s); 1379 break; 1380 } else if (prop & SA_IGNORE) { 1381 /* 1382 * Except for SIGCONT, shouldn't get here. 1383 * Default action is to ignore; drop it. 1384 */ 1385 break; /* == ignore */ 1386 } else 1387 goto keep; 1388 /* NOTREACHED */ 1389 case (long)SIG_IGN: 1390 /* 1391 * Masking above should prevent us ever trying 1392 * to take action on an ignored signal other 1393 * than SIGCONT, unless process is traced. 1394 */ 1395 if ((prop & SA_CONT) == 0 && 1396 (pr->ps_flags & PS_TRACED) == 0) 1397 printf("%s\n", __func__); 1398 break; /* == ignore */ 1399 default: 1400 /* 1401 * This signal has an action, let 1402 * postsig() process it. 1403 */ 1404 goto keep; 1405 } 1406 } 1407 /* NOTREACHED */ 1408 1409 keep: 1410 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1411 return (signum); 1412 } 1413 1414 /* 1415 * Put the argument process into the stopped state and notify the parent 1416 * via wakeup. Signals are handled elsewhere. The process must not be 1417 * on the run queue. 1418 */ 1419 void 1420 proc_stop(struct proc *p, int sw) 1421 { 1422 struct process *pr = p->p_p; 1423 1424 #ifdef MULTIPROCESSOR 1425 SCHED_ASSERT_LOCKED(); 1426 #endif 1427 1428 p->p_stat = SSTOP; 1429 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1430 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1431 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1432 /* 1433 * We need this soft interrupt to be handled fast. 1434 * Extra calls to softclock don't hurt. 1435 */ 1436 softintr_schedule(proc_stop_si); 1437 if (sw) 1438 mi_switch(); 1439 } 1440 1441 /* 1442 * Called from a soft interrupt to send signals to the parents of stopped 1443 * processes. 1444 * We can't do this in proc_stop because it's called with nasty locks held 1445 * and we would need recursive scheduler lock to deal with that. 1446 */ 1447 void 1448 proc_stop_sweep(void *v) 1449 { 1450 struct process *pr; 1451 1452 LIST_FOREACH(pr, &allprocess, ps_list) { 1453 if ((pr->ps_flags & PS_STOPPED) == 0) 1454 continue; 1455 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1456 1457 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1458 prsignal(pr->ps_pptr, SIGCHLD); 1459 wakeup(pr->ps_pptr); 1460 } 1461 } 1462 1463 /* 1464 * Take the action for the specified signal 1465 * from the current set of pending signals. 1466 */ 1467 void 1468 postsig(struct proc *p, int signum, struct sigctx *sctx) 1469 { 1470 u_long trapno; 1471 int mask, returnmask; 1472 siginfo_t si; 1473 union sigval sigval; 1474 int code; 1475 1476 KASSERT(signum != 0); 1477 1478 mask = sigmask(signum); 1479 atomic_clearbits_int(&p->p_siglist, mask); 1480 sigval.sival_ptr = NULL; 1481 1482 if (p->p_sisig != signum) { 1483 trapno = 0; 1484 code = SI_USER; 1485 sigval.sival_ptr = NULL; 1486 } else { 1487 trapno = p->p_sitrapno; 1488 code = p->p_sicode; 1489 sigval = p->p_sigval; 1490 } 1491 initsiginfo(&si, signum, trapno, code, sigval); 1492 1493 #ifdef KTRACE 1494 if (KTRPOINT(p, KTR_PSIG)) { 1495 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1496 p->p_oldmask : p->p_sigmask, code, &si); 1497 } 1498 #endif 1499 if (sctx->sig_action == SIG_DFL) { 1500 /* 1501 * Default action, where the default is to kill 1502 * the process. (Other cases were ignored above.) 1503 */ 1504 KERNEL_LOCK(); 1505 sigexit(p, signum); 1506 /* NOTREACHED */ 1507 } else { 1508 /* 1509 * If we get here, the signal must be caught. 1510 */ 1511 #ifdef DIAGNOSTIC 1512 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1513 panic("postsig action"); 1514 #endif 1515 /* 1516 * Set the new mask value and also defer further 1517 * occurrences of this signal. 1518 * 1519 * Special case: user has done a sigpause. Here the 1520 * current mask is not of interest, but rather the 1521 * mask from before the sigpause is what we want 1522 * restored after the signal processing is completed. 1523 */ 1524 if (p->p_flag & P_SIGSUSPEND) { 1525 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1526 returnmask = p->p_oldmask; 1527 } else { 1528 returnmask = p->p_sigmask; 1529 } 1530 if (p->p_sisig == signum) { 1531 p->p_sisig = 0; 1532 p->p_sitrapno = 0; 1533 p->p_sicode = SI_USER; 1534 p->p_sigval.sival_ptr = NULL; 1535 } 1536 1537 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1538 sctx->sig_info, sctx->sig_onstack)) { 1539 KERNEL_LOCK(); 1540 sigexit(p, SIGILL); 1541 /* NOTREACHED */ 1542 } 1543 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1544 } 1545 } 1546 1547 /* 1548 * Force the current process to exit with the specified signal, dumping core 1549 * if appropriate. We bypass the normal tests for masked and caught signals, 1550 * allowing unrecoverable failures to terminate the process without changing 1551 * signal state. Mark the accounting record with the signal termination. 1552 * If dumping core, save the signal number for the debugger. Calls exit and 1553 * does not return. 1554 */ 1555 void 1556 sigexit(struct proc *p, int signum) 1557 { 1558 /* Mark process as going away */ 1559 atomic_setbits_int(&p->p_flag, P_WEXIT); 1560 1561 p->p_p->ps_acflag |= AXSIG; 1562 if (sigprop[signum] & SA_CORE) { 1563 p->p_sisig = signum; 1564 1565 /* if there are other threads, pause them */ 1566 if (P_HASSIBLING(p)) 1567 single_thread_set(p, SINGLE_UNWIND); 1568 1569 if (coredump(p) == 0) 1570 signum |= WCOREFLAG; 1571 } 1572 exit1(p, 0, signum, EXIT_NORMAL); 1573 /* NOTREACHED */ 1574 } 1575 1576 /* 1577 * Send uncatchable SIGABRT for coredump. 1578 */ 1579 void 1580 sigabort(struct proc *p) 1581 { 1582 struct sigaction sa; 1583 1584 memset(&sa, 0, sizeof sa); 1585 sa.sa_handler = SIG_DFL; 1586 setsigvec(p, SIGABRT, &sa); 1587 atomic_clearbits_int(&p->p_sigmask, sigmask(SIGABRT)); 1588 psignal(p, SIGABRT); 1589 } 1590 1591 /* 1592 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1593 * thread, and 0 otherwise. 1594 */ 1595 int 1596 sigismasked(struct proc *p, int sig) 1597 { 1598 struct process *pr = p->p_p; 1599 int rv; 1600 1601 mtx_enter(&pr->ps_mtx); 1602 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1603 (p->p_sigmask & sigmask(sig)); 1604 mtx_leave(&pr->ps_mtx); 1605 1606 return !!rv; 1607 } 1608 1609 struct coredump_iostate { 1610 struct proc *io_proc; 1611 struct vnode *io_vp; 1612 struct ucred *io_cred; 1613 off_t io_offset; 1614 }; 1615 1616 /* 1617 * Dump core, into a file named "progname.core", unless the process was 1618 * setuid/setgid. 1619 */ 1620 int 1621 coredump(struct proc *p) 1622 { 1623 #ifdef SMALL_KERNEL 1624 return EPERM; 1625 #else 1626 struct process *pr = p->p_p; 1627 struct vnode *vp; 1628 struct ucred *cred = p->p_ucred; 1629 struct vmspace *vm = p->p_vmspace; 1630 struct nameidata nd; 1631 struct vattr vattr; 1632 struct coredump_iostate io; 1633 int error, len, incrash = 0; 1634 char *name; 1635 const char *dir = "/var/crash"; 1636 1637 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1638 1639 #ifdef PMAP_CHECK_COPYIN 1640 /* disable copyin checks, so we can write out text sections if needed */ 1641 p->p_vmspace->vm_map.check_copyin_count = 0; 1642 #endif 1643 1644 /* Don't dump if will exceed file size limit. */ 1645 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1646 return (EFBIG); 1647 1648 name = pool_get(&namei_pool, PR_WAITOK); 1649 1650 /* 1651 * If the process has inconsistent uids, nosuidcoredump 1652 * determines coredump placement policy. 1653 */ 1654 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1655 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1656 if (nosuidcoredump == 3) { 1657 /* 1658 * If the program directory does not exist, dumps of 1659 * that core will silently fail. 1660 */ 1661 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1662 dir, pr->ps_comm, pr->ps_pid); 1663 incrash = KERNELPATH; 1664 } else if (nosuidcoredump == 2) { 1665 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1666 dir, pr->ps_comm); 1667 incrash = KERNELPATH; 1668 } else { 1669 pool_put(&namei_pool, name); 1670 return (EPERM); 1671 } 1672 } else 1673 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1674 1675 if (len >= MAXPATHLEN) { 1676 pool_put(&namei_pool, name); 1677 return (EACCES); 1678 } 1679 1680 /* 1681 * Control the UID used to write out. The normal case uses 1682 * the real UID. If the sugid case is going to write into the 1683 * controlled directory, we do so as root. 1684 */ 1685 if (incrash == 0) { 1686 cred = crdup(cred); 1687 cred->cr_uid = cred->cr_ruid; 1688 cred->cr_gid = cred->cr_rgid; 1689 } else { 1690 if (p->p_fd->fd_rdir) { 1691 vrele(p->p_fd->fd_rdir); 1692 p->p_fd->fd_rdir = NULL; 1693 } 1694 p->p_ucred = crdup(p->p_ucred); 1695 crfree(cred); 1696 cred = p->p_ucred; 1697 crhold(cred); 1698 cred->cr_uid = 0; 1699 cred->cr_gid = 0; 1700 } 1701 1702 /* incrash should be 0 or KERNELPATH only */ 1703 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1704 1705 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1706 S_IRUSR | S_IWUSR); 1707 1708 if (error) 1709 goto out; 1710 1711 /* 1712 * Don't dump to non-regular files, files with links, or files 1713 * owned by someone else. 1714 */ 1715 vp = nd.ni_vp; 1716 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1717 VOP_UNLOCK(vp); 1718 vn_close(vp, FWRITE, cred, p); 1719 goto out; 1720 } 1721 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1722 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1723 vattr.va_uid != cred->cr_uid) { 1724 error = EACCES; 1725 VOP_UNLOCK(vp); 1726 vn_close(vp, FWRITE, cred, p); 1727 goto out; 1728 } 1729 VATTR_NULL(&vattr); 1730 vattr.va_size = 0; 1731 VOP_SETATTR(vp, &vattr, cred, p); 1732 pr->ps_acflag |= ACORE; 1733 1734 io.io_proc = p; 1735 io.io_vp = vp; 1736 io.io_cred = cred; 1737 io.io_offset = 0; 1738 VOP_UNLOCK(vp); 1739 vref(vp); 1740 error = vn_close(vp, FWRITE, cred, p); 1741 if (error == 0) 1742 error = coredump_elf(p, &io); 1743 vrele(vp); 1744 out: 1745 crfree(cred); 1746 pool_put(&namei_pool, name); 1747 return (error); 1748 #endif 1749 } 1750 1751 #ifndef SMALL_KERNEL 1752 int 1753 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1754 int isvnode) 1755 { 1756 struct coredump_iostate *io = cookie; 1757 off_t coffset = 0; 1758 size_t csize; 1759 int chunk, error; 1760 1761 csize = len; 1762 do { 1763 if (sigmask(SIGKILL) & 1764 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1765 return (EINTR); 1766 1767 /* Rest of the loop sleeps with lock held, so... */ 1768 yield(); 1769 1770 chunk = MIN(csize, MAXPHYS); 1771 error = vn_rdwr(UIO_WRITE, io->io_vp, 1772 (caddr_t)data + coffset, chunk, 1773 io->io_offset + coffset, segflg, 1774 IO_UNIT, io->io_cred, NULL, io->io_proc); 1775 if (error && (error != EFAULT || !isvnode)) { 1776 struct process *pr = io->io_proc->p_p; 1777 1778 if (error == ENOSPC) 1779 log(LOG_ERR, 1780 "coredump of %s(%d) failed, filesystem full\n", 1781 pr->ps_comm, pr->ps_pid); 1782 else 1783 log(LOG_ERR, 1784 "coredump of %s(%d), write failed: errno %d\n", 1785 pr->ps_comm, pr->ps_pid, error); 1786 return (error); 1787 } 1788 1789 coffset += chunk; 1790 csize -= chunk; 1791 } while (csize > 0); 1792 1793 io->io_offset += len; 1794 return (0); 1795 } 1796 1797 void 1798 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1799 { 1800 struct coredump_iostate *io = cookie; 1801 1802 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1803 } 1804 1805 #endif /* !SMALL_KERNEL */ 1806 1807 /* 1808 * Nonexistent system call-- signal process (may want to handle it). 1809 * Flag error in case process won't see signal immediately (blocked or ignored). 1810 */ 1811 int 1812 sys_nosys(struct proc *p, void *v, register_t *retval) 1813 { 1814 ptsignal(p, SIGSYS, STHREAD); 1815 return (ENOSYS); 1816 } 1817 1818 int 1819 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1820 { 1821 struct sys___thrsigdivert_args /* { 1822 syscallarg(sigset_t) sigmask; 1823 syscallarg(siginfo_t *) info; 1824 syscallarg(const struct timespec *) timeout; 1825 } */ *uap = v; 1826 struct sigctx ctx; 1827 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1828 siginfo_t si; 1829 uint64_t nsecs = INFSLP; 1830 int timeinvalid = 0; 1831 int error = 0; 1832 1833 memset(&si, 0, sizeof(si)); 1834 1835 if (SCARG(uap, timeout) != NULL) { 1836 struct timespec ts; 1837 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1838 return (error); 1839 #ifdef KTRACE 1840 if (KTRPOINT(p, KTR_STRUCT)) 1841 ktrreltimespec(p, &ts); 1842 #endif 1843 if (!timespecisvalid(&ts)) 1844 timeinvalid = 1; 1845 else 1846 nsecs = TIMESPEC_TO_NSEC(&ts); 1847 } 1848 1849 dosigsuspend(p, p->p_sigmask &~ mask); 1850 for (;;) { 1851 si.si_signo = cursig(p, &ctx); 1852 if (si.si_signo != 0) { 1853 sigset_t smask = sigmask(si.si_signo); 1854 if (smask & mask) { 1855 atomic_clearbits_int(&p->p_siglist, smask); 1856 error = 0; 1857 break; 1858 } 1859 } 1860 1861 /* per-POSIX, delay this error until after the above */ 1862 if (timeinvalid) 1863 error = EINVAL; 1864 /* per-POSIX, return immediately if timeout is zero-valued */ 1865 if (nsecs == 0) 1866 error = EAGAIN; 1867 1868 if (error != 0) 1869 break; 1870 1871 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1872 } 1873 1874 if (error == 0) { 1875 *retval = si.si_signo; 1876 if (SCARG(uap, info) != NULL) { 1877 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1878 #ifdef KTRACE 1879 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1880 ktrsiginfo(p, &si); 1881 #endif 1882 } 1883 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1884 /* 1885 * Restarting is wrong if there's a timeout, as it'll be 1886 * for the same interval again 1887 */ 1888 error = EINTR; 1889 } 1890 1891 return (error); 1892 } 1893 1894 void 1895 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1896 { 1897 memset(si, 0, sizeof(*si)); 1898 1899 si->si_signo = sig; 1900 si->si_code = code; 1901 if (code == SI_USER) { 1902 si->si_value = val; 1903 } else { 1904 switch (sig) { 1905 case SIGSEGV: 1906 case SIGILL: 1907 case SIGBUS: 1908 case SIGFPE: 1909 si->si_addr = val.sival_ptr; 1910 si->si_trapno = trapno; 1911 break; 1912 case SIGXFSZ: 1913 break; 1914 } 1915 } 1916 } 1917 1918 int 1919 filt_sigattach(struct knote *kn) 1920 { 1921 struct process *pr = curproc->p_p; 1922 int s; 1923 1924 if (kn->kn_id >= NSIG) 1925 return EINVAL; 1926 1927 kn->kn_ptr.p_process = pr; 1928 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1929 1930 s = splhigh(); 1931 klist_insert_locked(&pr->ps_klist, kn); 1932 splx(s); 1933 1934 return (0); 1935 } 1936 1937 void 1938 filt_sigdetach(struct knote *kn) 1939 { 1940 struct process *pr = kn->kn_ptr.p_process; 1941 int s; 1942 1943 s = splhigh(); 1944 klist_remove_locked(&pr->ps_klist, kn); 1945 splx(s); 1946 } 1947 1948 /* 1949 * signal knotes are shared with proc knotes, so we apply a mask to 1950 * the hint in order to differentiate them from process hints. This 1951 * could be avoided by using a signal-specific knote list, but probably 1952 * isn't worth the trouble. 1953 */ 1954 int 1955 filt_signal(struct knote *kn, long hint) 1956 { 1957 1958 if (hint & NOTE_SIGNAL) { 1959 hint &= ~NOTE_SIGNAL; 1960 1961 if (kn->kn_id == hint) 1962 kn->kn_data++; 1963 } 1964 return (kn->kn_data != 0); 1965 } 1966 1967 void 1968 userret(struct proc *p) 1969 { 1970 struct sigctx ctx; 1971 int signum; 1972 1973 if (p->p_flag & P_SUSPSINGLE) 1974 single_thread_check(p, 0); 1975 1976 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1977 if (p->p_flag & P_PROFPEND) { 1978 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1979 KERNEL_LOCK(); 1980 psignal(p, SIGPROF); 1981 KERNEL_UNLOCK(); 1982 } 1983 if (p->p_flag & P_ALRMPEND) { 1984 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1985 KERNEL_LOCK(); 1986 psignal(p, SIGVTALRM); 1987 KERNEL_UNLOCK(); 1988 } 1989 1990 if (SIGPENDING(p) != 0) { 1991 while ((signum = cursig(p, &ctx)) != 0) 1992 postsig(p, signum, &ctx); 1993 } 1994 1995 /* 1996 * If P_SIGSUSPEND is still set here, then we still need to restore 1997 * the original sigmask before returning to userspace. Also, this 1998 * might unmask some pending signals, so we need to check a second 1999 * time for signals to post. 2000 */ 2001 if (p->p_flag & P_SIGSUSPEND) { 2002 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2003 p->p_sigmask = p->p_oldmask; 2004 2005 while ((signum = cursig(p, &ctx)) != 0) 2006 postsig(p, signum, &ctx); 2007 } 2008 2009 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2010 2011 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2012 } 2013 2014 int 2015 single_thread_check_locked(struct proc *p, int deep, int s) 2016 { 2017 struct process *pr = p->p_p; 2018 2019 SCHED_ASSERT_LOCKED(); 2020 2021 if (pr->ps_single == NULL || pr->ps_single == p) 2022 return (0); 2023 2024 do { 2025 /* if we're in deep, we need to unwind to the edge */ 2026 if (deep) { 2027 if (pr->ps_flags & PS_SINGLEUNWIND) 2028 return (ERESTART); 2029 if (pr->ps_flags & PS_SINGLEEXIT) 2030 return (EINTR); 2031 } 2032 2033 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2034 wakeup(&pr->ps_singlecount); 2035 2036 if (pr->ps_flags & PS_SINGLEEXIT) { 2037 SCHED_UNLOCK(s); 2038 KERNEL_LOCK(); 2039 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2040 /* NOTREACHED */ 2041 } 2042 2043 /* not exiting and don't need to unwind, so suspend */ 2044 p->p_stat = SSTOP; 2045 mi_switch(); 2046 } while (pr->ps_single != NULL); 2047 2048 return (0); 2049 } 2050 2051 int 2052 single_thread_check(struct proc *p, int deep) 2053 { 2054 int s, error; 2055 2056 SCHED_LOCK(s); 2057 error = single_thread_check_locked(p, deep, s); 2058 SCHED_UNLOCK(s); 2059 2060 return error; 2061 } 2062 2063 /* 2064 * Stop other threads in the process. The mode controls how and 2065 * where the other threads should stop: 2066 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2067 * single_thread_clear()) 2068 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2069 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2070 * - SINGLE_EXIT: unwind to kernel boundary and exit 2071 */ 2072 int 2073 single_thread_set(struct proc *p, int flags) 2074 { 2075 struct process *pr = p->p_p; 2076 struct proc *q; 2077 int error, s, mode = flags & SINGLE_MASK; 2078 2079 KASSERT(curproc == p); 2080 2081 SCHED_LOCK(s); 2082 error = single_thread_check_locked(p, flags & SINGLE_DEEP, s); 2083 if (error) { 2084 SCHED_UNLOCK(s); 2085 return error; 2086 } 2087 2088 switch (mode) { 2089 case SINGLE_SUSPEND: 2090 break; 2091 case SINGLE_UNWIND: 2092 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2093 break; 2094 case SINGLE_EXIT: 2095 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2096 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2097 break; 2098 #ifdef DIAGNOSTIC 2099 default: 2100 panic("single_thread_mode = %d", mode); 2101 #endif 2102 } 2103 pr->ps_singlecount = 0; 2104 membar_producer(); 2105 pr->ps_single = p; 2106 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2107 if (q == p) 2108 continue; 2109 if (q->p_flag & P_WEXIT) { 2110 if (mode == SINGLE_EXIT) { 2111 if (q->p_stat == SSTOP) { 2112 setrunnable(q); 2113 atomic_inc_int(&pr->ps_singlecount); 2114 } 2115 } 2116 continue; 2117 } 2118 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2119 switch (q->p_stat) { 2120 case SIDL: 2121 case SRUN: 2122 atomic_inc_int(&pr->ps_singlecount); 2123 break; 2124 case SSLEEP: 2125 /* if it's not interruptible, then just have to wait */ 2126 if (q->p_flag & P_SINTR) { 2127 /* merely need to suspend? just stop it */ 2128 if (mode == SINGLE_SUSPEND) { 2129 q->p_stat = SSTOP; 2130 break; 2131 } 2132 /* need to unwind or exit, so wake it */ 2133 setrunnable(q); 2134 } 2135 atomic_inc_int(&pr->ps_singlecount); 2136 break; 2137 case SSTOP: 2138 if (mode == SINGLE_EXIT) { 2139 setrunnable(q); 2140 atomic_inc_int(&pr->ps_singlecount); 2141 } 2142 break; 2143 case SDEAD: 2144 break; 2145 case SONPROC: 2146 atomic_inc_int(&pr->ps_singlecount); 2147 signotify(q); 2148 break; 2149 } 2150 } 2151 SCHED_UNLOCK(s); 2152 2153 if ((flags & SINGLE_NOWAIT) == 0) 2154 single_thread_wait(pr, 1); 2155 2156 return 0; 2157 } 2158 2159 /* 2160 * Wait for other threads to stop. If recheck is false then the function 2161 * returns non-zero if the caller needs to restart the check else 0 is 2162 * returned. If recheck is true the return value is always 0. 2163 */ 2164 int 2165 single_thread_wait(struct process *pr, int recheck) 2166 { 2167 int wait; 2168 2169 /* wait until they're all suspended */ 2170 wait = pr->ps_singlecount > 0; 2171 while (wait) { 2172 sleep_setup(&pr->ps_singlecount, PWAIT, "suspend"); 2173 wait = pr->ps_singlecount > 0; 2174 sleep_finish(0, wait); 2175 if (!recheck) 2176 break; 2177 } 2178 2179 return wait; 2180 } 2181 2182 void 2183 single_thread_clear(struct proc *p, int flag) 2184 { 2185 struct process *pr = p->p_p; 2186 struct proc *q; 2187 int s; 2188 2189 KASSERT(pr->ps_single == p); 2190 KASSERT(curproc == p); 2191 2192 SCHED_LOCK(s); 2193 pr->ps_single = NULL; 2194 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2195 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2196 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2197 continue; 2198 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2199 2200 /* 2201 * if the thread was only stopped for single threading 2202 * then clearing that either makes it runnable or puts 2203 * it back into some sleep queue 2204 */ 2205 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2206 if (q->p_wchan == NULL) 2207 setrunnable(q); 2208 else { 2209 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2210 q->p_stat = SSLEEP; 2211 } 2212 } 2213 } 2214 SCHED_UNLOCK(s); 2215 } 2216 2217 void 2218 sigio_del(struct sigiolst *rmlist) 2219 { 2220 struct sigio *sigio; 2221 2222 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2223 LIST_REMOVE(sigio, sio_pgsigio); 2224 crfree(sigio->sio_ucred); 2225 free(sigio, M_SIGIO, sizeof(*sigio)); 2226 } 2227 } 2228 2229 void 2230 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2231 { 2232 struct sigio *sigio; 2233 2234 MUTEX_ASSERT_LOCKED(&sigio_lock); 2235 2236 sigio = sir->sir_sigio; 2237 if (sigio != NULL) { 2238 KASSERT(sigio->sio_myref == sir); 2239 sir->sir_sigio = NULL; 2240 2241 if (sigio->sio_pgid > 0) 2242 sigio->sio_proc = NULL; 2243 else 2244 sigio->sio_pgrp = NULL; 2245 LIST_REMOVE(sigio, sio_pgsigio); 2246 2247 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2248 } 2249 } 2250 2251 void 2252 sigio_free(struct sigio_ref *sir) 2253 { 2254 struct sigiolst rmlist; 2255 2256 if (sir->sir_sigio == NULL) 2257 return; 2258 2259 LIST_INIT(&rmlist); 2260 2261 mtx_enter(&sigio_lock); 2262 sigio_unlink(sir, &rmlist); 2263 mtx_leave(&sigio_lock); 2264 2265 sigio_del(&rmlist); 2266 } 2267 2268 void 2269 sigio_freelist(struct sigiolst *sigiolst) 2270 { 2271 struct sigiolst rmlist; 2272 struct sigio *sigio; 2273 2274 if (LIST_EMPTY(sigiolst)) 2275 return; 2276 2277 LIST_INIT(&rmlist); 2278 2279 mtx_enter(&sigio_lock); 2280 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2281 sigio_unlink(sigio->sio_myref, &rmlist); 2282 mtx_leave(&sigio_lock); 2283 2284 sigio_del(&rmlist); 2285 } 2286 2287 int 2288 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2289 { 2290 struct sigiolst rmlist; 2291 struct proc *p = curproc; 2292 struct pgrp *pgrp = NULL; 2293 struct process *pr = NULL; 2294 struct sigio *sigio; 2295 int error; 2296 pid_t pgid = *(int *)data; 2297 2298 if (pgid == 0) { 2299 sigio_free(sir); 2300 return (0); 2301 } 2302 2303 if (cmd == TIOCSPGRP) { 2304 if (pgid < 0) 2305 return (EINVAL); 2306 pgid = -pgid; 2307 } 2308 2309 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2310 sigio->sio_pgid = pgid; 2311 sigio->sio_ucred = crhold(p->p_ucred); 2312 sigio->sio_myref = sir; 2313 2314 LIST_INIT(&rmlist); 2315 2316 /* 2317 * The kernel lock, and not sleeping between prfind()/pgfind() and 2318 * linking of the sigio ensure that the process or process group does 2319 * not disappear unexpectedly. 2320 */ 2321 KERNEL_LOCK(); 2322 mtx_enter(&sigio_lock); 2323 2324 if (pgid > 0) { 2325 pr = prfind(pgid); 2326 if (pr == NULL) { 2327 error = ESRCH; 2328 goto fail; 2329 } 2330 2331 /* 2332 * Policy - Don't allow a process to FSETOWN a process 2333 * in another session. 2334 * 2335 * Remove this test to allow maximum flexibility or 2336 * restrict FSETOWN to the current process or process 2337 * group for maximum safety. 2338 */ 2339 if (pr->ps_session != p->p_p->ps_session) { 2340 error = EPERM; 2341 goto fail; 2342 } 2343 2344 if ((pr->ps_flags & PS_EXITING) != 0) { 2345 error = ESRCH; 2346 goto fail; 2347 } 2348 } else /* if (pgid < 0) */ { 2349 pgrp = pgfind(-pgid); 2350 if (pgrp == NULL) { 2351 error = ESRCH; 2352 goto fail; 2353 } 2354 2355 /* 2356 * Policy - Don't allow a process to FSETOWN a process 2357 * in another session. 2358 * 2359 * Remove this test to allow maximum flexibility or 2360 * restrict FSETOWN to the current process or process 2361 * group for maximum safety. 2362 */ 2363 if (pgrp->pg_session != p->p_p->ps_session) { 2364 error = EPERM; 2365 goto fail; 2366 } 2367 } 2368 2369 if (pgid > 0) { 2370 sigio->sio_proc = pr; 2371 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2372 } else { 2373 sigio->sio_pgrp = pgrp; 2374 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2375 } 2376 2377 sigio_unlink(sir, &rmlist); 2378 sir->sir_sigio = sigio; 2379 2380 mtx_leave(&sigio_lock); 2381 KERNEL_UNLOCK(); 2382 2383 sigio_del(&rmlist); 2384 2385 return (0); 2386 2387 fail: 2388 mtx_leave(&sigio_lock); 2389 KERNEL_UNLOCK(); 2390 2391 crfree(sigio->sio_ucred); 2392 free(sigio, M_SIGIO, sizeof(*sigio)); 2393 2394 return (error); 2395 } 2396 2397 void 2398 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2399 { 2400 struct sigio *sigio; 2401 pid_t pgid = 0; 2402 2403 mtx_enter(&sigio_lock); 2404 sigio = sir->sir_sigio; 2405 if (sigio != NULL) 2406 pgid = sigio->sio_pgid; 2407 mtx_leave(&sigio_lock); 2408 2409 if (cmd == TIOCGPGRP) 2410 pgid = -pgid; 2411 2412 *(int *)data = pgid; 2413 } 2414 2415 void 2416 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2417 { 2418 struct sigiolst rmlist; 2419 struct sigio *newsigio, *sigio; 2420 2421 sigio_free(dst); 2422 2423 if (src->sir_sigio == NULL) 2424 return; 2425 2426 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2427 LIST_INIT(&rmlist); 2428 2429 mtx_enter(&sigio_lock); 2430 2431 sigio = src->sir_sigio; 2432 if (sigio == NULL) { 2433 mtx_leave(&sigio_lock); 2434 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2435 return; 2436 } 2437 2438 newsigio->sio_pgid = sigio->sio_pgid; 2439 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2440 newsigio->sio_myref = dst; 2441 if (newsigio->sio_pgid > 0) { 2442 newsigio->sio_proc = sigio->sio_proc; 2443 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2444 sio_pgsigio); 2445 } else { 2446 newsigio->sio_pgrp = sigio->sio_pgrp; 2447 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2448 sio_pgsigio); 2449 } 2450 2451 sigio_unlink(dst, &rmlist); 2452 dst->sir_sigio = newsigio; 2453 2454 mtx_leave(&sigio_lock); 2455 2456 sigio_del(&rmlist); 2457 } 2458