1 /* $OpenBSD: kern_sig.c,v 1.303 2023/01/02 23:09:48 guenther 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 case SIGBUS: 803 case SIGSEGV: 804 pr->ps_acflag |= ATRAP; 805 break; 806 } 807 808 mask = sigmask(signum); 809 setsigctx(p, signum, &ctx); 810 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 811 (p->p_sigmask & mask) == 0) { 812 siginfo_t si; 813 814 initsiginfo(&si, signum, trapno, code, sigval); 815 #ifdef KTRACE 816 if (KTRPOINT(p, KTR_PSIG)) { 817 ktrpsig(p, signum, ctx.sig_action, 818 p->p_sigmask, code, &si); 819 } 820 #endif 821 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 822 ctx.sig_info, ctx.sig_onstack)) { 823 KERNEL_LOCK(); 824 sigexit(p, SIGILL); 825 /* NOTREACHED */ 826 } 827 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 828 } else { 829 p->p_sisig = signum; 830 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 831 p->p_sicode = code; 832 p->p_sigval = sigval; 833 834 /* 835 * If traced, stop if signal is masked, and stay stopped 836 * until released by the debugger. If our parent process 837 * is waiting for us, don't hang as we could deadlock. 838 */ 839 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 840 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 841 int s; 842 843 single_thread_set(p, SINGLE_SUSPEND, 0); 844 pr->ps_xsig = signum; 845 846 SCHED_LOCK(s); 847 proc_stop(p, 1); 848 SCHED_UNLOCK(s); 849 850 signum = pr->ps_xsig; 851 single_thread_clear(p, 0); 852 853 /* 854 * If we are no longer being traced, or the parent 855 * didn't give us a signal, skip sending the signal. 856 */ 857 if ((pr->ps_flags & PS_TRACED) == 0 || 858 signum == 0) 859 return; 860 861 /* update signal info */ 862 p->p_sisig = signum; 863 mask = sigmask(signum); 864 } 865 866 /* 867 * Signals like SIGBUS and SIGSEGV should not, when 868 * generated by the kernel, be ignorable or blockable. 869 * If it is and we're not being traced, then just kill 870 * the process. 871 * After vfs_shutdown(9), init(8) cannot receive signals 872 * because new code pages of the signal handler cannot be 873 * mapped from halted storage. init(8) may not die or the 874 * kernel panics. Better loop between signal handler and 875 * page fault trap until the machine is halted. 876 */ 877 if ((pr->ps_flags & PS_TRACED) == 0 && 878 (sigprop[signum] & SA_KILL) && 879 ((p->p_sigmask & mask) || ctx.sig_ignore) && 880 pr->ps_pid != 1) { 881 KERNEL_LOCK(); 882 sigexit(p, signum); 883 /* NOTREACHED */ 884 } 885 KERNEL_LOCK(); 886 ptsignal(p, signum, STHREAD); 887 KERNEL_UNLOCK(); 888 } 889 } 890 891 /* 892 * Send the signal to the process. If the signal has an action, the action 893 * is usually performed by the target process rather than the caller; we add 894 * the signal to the set of pending signals for the process. 895 * 896 * Exceptions: 897 * o When a stop signal is sent to a sleeping process that takes the 898 * default action, the process is stopped without awakening it. 899 * o SIGCONT restarts stopped processes (or puts them back to sleep) 900 * regardless of the signal action (eg, blocked or ignored). 901 * 902 * Other ignored signals are discarded immediately. 903 */ 904 void 905 psignal(struct proc *p, int signum) 906 { 907 ptsignal(p, signum, SPROCESS); 908 } 909 910 /* 911 * type = SPROCESS process signal, can be diverted (sigwait()) 912 * type = STHREAD thread signal, but should be propagated if unhandled 913 * type = SPROPAGATED propagated to this thread, so don't propagate again 914 */ 915 void 916 ptsignal(struct proc *p, int signum, enum signal_type type) 917 { 918 int s, prop; 919 sig_t action; 920 int mask; 921 int *siglist; 922 struct process *pr = p->p_p; 923 struct proc *q; 924 int wakeparent = 0; 925 926 KERNEL_ASSERT_LOCKED(); 927 928 #ifdef DIAGNOSTIC 929 if ((u_int)signum >= NSIG || signum == 0) 930 panic("psignal signal number"); 931 #endif 932 933 /* Ignore signal if the target process is exiting */ 934 if (pr->ps_flags & PS_EXITING) 935 return; 936 937 mask = sigmask(signum); 938 939 if (type == SPROCESS) { 940 /* Accept SIGKILL to coredumping processes */ 941 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 942 atomic_setbits_int(&pr->ps_siglist, mask); 943 return; 944 } 945 946 /* 947 * If the current thread can process the signal 948 * immediately (it's unblocked) then have it take it. 949 */ 950 q = curproc; 951 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 952 (q->p_sigmask & mask) == 0) 953 p = q; 954 else { 955 /* 956 * A process-wide signal can be diverted to a 957 * different thread that's in sigwait() for this 958 * signal. If there isn't such a thread, then 959 * pick a thread that doesn't have it blocked so 960 * that the stop/kill consideration isn't 961 * delayed. Otherwise, mark it pending on the 962 * main thread. 963 */ 964 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 965 /* ignore exiting threads */ 966 if (q->p_flag & P_WEXIT) 967 continue; 968 969 /* skip threads that have the signal blocked */ 970 if ((q->p_sigmask & mask) != 0) 971 continue; 972 973 /* okay, could send to this thread */ 974 p = q; 975 976 /* 977 * sigsuspend, sigwait, ppoll/pselect, etc? 978 * Definitely go to this thread, as it's 979 * already blocked in the kernel. 980 */ 981 if (q->p_flag & P_SIGSUSPEND) 982 break; 983 } 984 } 985 } 986 987 if (type != SPROPAGATED) 988 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 989 990 prop = sigprop[signum]; 991 992 /* 993 * If proc is traced, always give parent a chance. 994 */ 995 if (pr->ps_flags & PS_TRACED) { 996 action = SIG_DFL; 997 } else { 998 sigset_t sigcatch, sigignore; 999 1000 /* 1001 * If the signal is being ignored, 1002 * then we forget about it immediately. 1003 * (Note: we don't set SIGCONT in ps_sigignore, 1004 * and if it is set to SIG_IGN, 1005 * action will be SIG_DFL here.) 1006 */ 1007 mtx_enter(&pr->ps_mtx); 1008 sigignore = pr->ps_sigacts->ps_sigignore; 1009 sigcatch = pr->ps_sigacts->ps_sigcatch; 1010 mtx_leave(&pr->ps_mtx); 1011 1012 if (sigignore & mask) 1013 return; 1014 if (p->p_sigmask & mask) { 1015 action = SIG_HOLD; 1016 } else if (sigcatch & mask) { 1017 action = SIG_CATCH; 1018 } else { 1019 action = SIG_DFL; 1020 1021 if (prop & SA_KILL && pr->ps_nice > NZERO) 1022 pr->ps_nice = NZERO; 1023 1024 /* 1025 * If sending a tty stop signal to a member of an 1026 * orphaned process group, discard the signal here if 1027 * the action is default; don't stop the process below 1028 * if sleeping, and don't clear any pending SIGCONT. 1029 */ 1030 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1031 return; 1032 } 1033 } 1034 /* 1035 * If delivered to process, mark as pending there. Continue and stop 1036 * signals will be propagated to all threads. So they are always 1037 * marked at thread level. 1038 */ 1039 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1040 if (prop & SA_CONT) { 1041 siglist = &p->p_siglist; 1042 atomic_clearbits_int(siglist, STOPSIGMASK); 1043 } 1044 if (prop & SA_STOP) { 1045 siglist = &p->p_siglist; 1046 atomic_clearbits_int(siglist, CONTSIGMASK); 1047 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1048 } 1049 1050 /* 1051 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1052 */ 1053 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1054 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1055 if (q != p) 1056 ptsignal(q, signum, SPROPAGATED); 1057 1058 /* 1059 * Defer further processing for signals which are held, 1060 * except that stopped processes must be continued by SIGCONT. 1061 */ 1062 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || 1063 p->p_stat != SSTOP)) { 1064 atomic_setbits_int(siglist, mask); 1065 return; 1066 } 1067 1068 SCHED_LOCK(s); 1069 1070 switch (p->p_stat) { 1071 1072 case SSLEEP: 1073 /* 1074 * If process is sleeping uninterruptibly 1075 * we can't interrupt the sleep... the signal will 1076 * be noticed when the process returns through 1077 * trap() or syscall(). 1078 */ 1079 if ((p->p_flag & P_SINTR) == 0) 1080 goto out; 1081 /* 1082 * Process is sleeping and traced... make it runnable 1083 * so it can discover the signal in cursig() and stop 1084 * for the parent. 1085 */ 1086 if (pr->ps_flags & PS_TRACED) 1087 goto run; 1088 /* 1089 * If SIGCONT is default (or ignored) and process is 1090 * asleep, we are finished; the process should not 1091 * be awakened. 1092 */ 1093 if ((prop & SA_CONT) && action == SIG_DFL) { 1094 mask = 0; 1095 goto out; 1096 } 1097 /* 1098 * When a sleeping process receives a stop 1099 * signal, process immediately if possible. 1100 */ 1101 if ((prop & SA_STOP) && action == SIG_DFL) { 1102 /* 1103 * If a child holding parent blocked, 1104 * stopping could cause deadlock. 1105 */ 1106 if (pr->ps_flags & PS_PPWAIT) 1107 goto out; 1108 mask = 0; 1109 pr->ps_xsig = signum; 1110 proc_stop(p, 0); 1111 goto out; 1112 } 1113 /* 1114 * All other (caught or default) signals 1115 * cause the process to run. 1116 */ 1117 goto runfast; 1118 /* NOTREACHED */ 1119 1120 case SSTOP: 1121 /* 1122 * If traced process is already stopped, 1123 * then no further action is necessary. 1124 */ 1125 if (pr->ps_flags & PS_TRACED) 1126 goto out; 1127 1128 /* 1129 * Kill signal always sets processes running. 1130 */ 1131 if (signum == SIGKILL) { 1132 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1133 goto runfast; 1134 } 1135 1136 if (prop & SA_CONT) { 1137 /* 1138 * If SIGCONT is default (or ignored), we continue the 1139 * process but don't leave the signal in p_siglist, as 1140 * it has no further action. If SIGCONT is held, we 1141 * continue the process and leave the signal in 1142 * p_siglist. If the process catches SIGCONT, let it 1143 * handle the signal itself. If it isn't waiting on 1144 * an event, then it goes back to run state. 1145 * Otherwise, process goes back to sleep state. 1146 */ 1147 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1148 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1149 wakeparent = 1; 1150 if (action == SIG_DFL) 1151 atomic_clearbits_int(siglist, mask); 1152 if (action == SIG_CATCH) 1153 goto runfast; 1154 if (p->p_wchan == NULL) 1155 goto run; 1156 p->p_stat = SSLEEP; 1157 goto out; 1158 } 1159 1160 if (prop & SA_STOP) { 1161 /* 1162 * Already stopped, don't need to stop again. 1163 * (If we did the shell could get confused.) 1164 */ 1165 mask = 0; 1166 goto out; 1167 } 1168 1169 /* 1170 * If process is sleeping interruptibly, then simulate a 1171 * wakeup so that when it is continued, it will be made 1172 * runnable and can look at the signal. But don't make 1173 * the process runnable, leave it stopped. 1174 */ 1175 if (p->p_flag & P_SINTR) 1176 unsleep(p); 1177 goto out; 1178 1179 case SONPROC: 1180 /* set siglist before issuing the ast */ 1181 atomic_setbits_int(siglist, mask); 1182 mask = 0; 1183 signotify(p); 1184 /* FALLTHROUGH */ 1185 default: 1186 /* 1187 * SRUN, SIDL, SDEAD do nothing with the signal, 1188 * other than kicking ourselves if we are running. 1189 * It will either never be noticed, or noticed very soon. 1190 */ 1191 goto out; 1192 } 1193 /* NOTREACHED */ 1194 1195 runfast: 1196 /* 1197 * Raise priority to at least PUSER. 1198 */ 1199 if (p->p_usrpri > PUSER) 1200 p->p_usrpri = PUSER; 1201 run: 1202 setrunnable(p); 1203 out: 1204 /* finally adjust siglist */ 1205 if (mask) 1206 atomic_setbits_int(siglist, mask); 1207 SCHED_UNLOCK(s); 1208 if (wakeparent) 1209 wakeup(pr->ps_pptr); 1210 } 1211 1212 /* fill the signal context which should be used by postsig() and issignal() */ 1213 void 1214 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1215 { 1216 struct sigacts *ps = p->p_p->ps_sigacts; 1217 sigset_t mask; 1218 1219 mtx_enter(&p->p_p->ps_mtx); 1220 mask = sigmask(signum); 1221 sctx->sig_action = ps->ps_sigact[signum]; 1222 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1223 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1224 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1225 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1226 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1227 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1228 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1229 mtx_leave(&p->p_p->ps_mtx); 1230 } 1231 1232 /* 1233 * Determine signal that should be delivered to process p, the current 1234 * process, 0 if none. 1235 * 1236 * If the current process has received a signal (should be caught or cause 1237 * termination, should interrupt current syscall), return the signal number. 1238 * Stop signals with default action are processed immediately, then cleared; 1239 * they aren't returned. This is checked after each entry to the system for 1240 * a syscall or trap. The normal call sequence is 1241 * 1242 * while (signum = cursig(curproc, &ctx)) 1243 * postsig(signum, &ctx); 1244 * 1245 * Assumes that if the P_SINTR flag is set, we're holding both the 1246 * kernel and scheduler locks. 1247 */ 1248 int 1249 cursig(struct proc *p, struct sigctx *sctx) 1250 { 1251 struct process *pr = p->p_p; 1252 int signum, mask, prop; 1253 int dolock = (p->p_flag & P_SINTR) == 0; 1254 sigset_t ps_siglist; 1255 int s; 1256 1257 KASSERT(p == curproc); 1258 1259 for (;;) { 1260 ps_siglist = READ_ONCE(pr->ps_siglist); 1261 membar_consumer(); 1262 mask = SIGPENDING(p); 1263 if (pr->ps_flags & PS_PPWAIT) 1264 mask &= ~STOPSIGMASK; 1265 if (mask == 0) /* no signal to send */ 1266 return (0); 1267 signum = ffs((long)mask); 1268 mask = sigmask(signum); 1269 1270 /* take the signal! */ 1271 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1272 ps_siglist & ~mask) != ps_siglist) { 1273 /* lost race taking the process signal, restart */ 1274 continue; 1275 } 1276 atomic_clearbits_int(&p->p_siglist, mask); 1277 setsigctx(p, signum, sctx); 1278 1279 /* 1280 * We should see pending but ignored signals 1281 * only if PS_TRACED was on when they were posted. 1282 */ 1283 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1284 continue; 1285 1286 /* 1287 * If traced, always stop, and stay stopped until released 1288 * by the debugger. If our parent process is waiting for 1289 * us, don't hang as we could deadlock. 1290 */ 1291 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1292 signum != SIGKILL) { 1293 single_thread_set(p, SINGLE_SUSPEND, 0); 1294 pr->ps_xsig = signum; 1295 1296 if (dolock) 1297 SCHED_LOCK(s); 1298 proc_stop(p, 1); 1299 if (dolock) 1300 SCHED_UNLOCK(s); 1301 1302 /* 1303 * re-take the signal before releasing 1304 * the other threads. Must check the continue 1305 * conditions below and only take the signal if 1306 * those are not true. 1307 */ 1308 signum = pr->ps_xsig; 1309 mask = sigmask(signum); 1310 setsigctx(p, signum, sctx); 1311 if (!((pr->ps_flags & PS_TRACED) == 0 || 1312 signum == 0 || 1313 (p->p_sigmask & mask) != 0)) { 1314 atomic_clearbits_int(&p->p_siglist, mask); 1315 atomic_clearbits_int(&pr->ps_siglist, mask); 1316 } 1317 1318 single_thread_clear(p, 0); 1319 1320 /* 1321 * If we are no longer being traced, or the parent 1322 * didn't give us a signal, look for more signals. 1323 */ 1324 if ((pr->ps_flags & PS_TRACED) == 0 || 1325 signum == 0) 1326 continue; 1327 1328 /* 1329 * If the new signal is being masked, look for other 1330 * signals. 1331 */ 1332 if ((p->p_sigmask & mask) != 0) 1333 continue; 1334 1335 } 1336 1337 prop = sigprop[signum]; 1338 1339 /* 1340 * Decide whether the signal should be returned. 1341 * Return the signal's number, or fall through 1342 * to clear it from the pending mask. 1343 */ 1344 switch ((long)sctx->sig_action) { 1345 case (long)SIG_DFL: 1346 /* 1347 * Don't take default actions on system processes. 1348 */ 1349 if (pr->ps_pid <= 1) { 1350 #ifdef DIAGNOSTIC 1351 /* 1352 * Are you sure you want to ignore SIGSEGV 1353 * in init? XXX 1354 */ 1355 printf("Process (pid %d) got signal" 1356 " %d\n", pr->ps_pid, signum); 1357 #endif 1358 break; /* == ignore */ 1359 } 1360 /* 1361 * If there is a pending stop signal to process 1362 * with default action, stop here, 1363 * then clear the signal. However, 1364 * if process is member of an orphaned 1365 * process group, ignore tty stop signals. 1366 */ 1367 if (prop & SA_STOP) { 1368 if (pr->ps_flags & PS_TRACED || 1369 (pr->ps_pgrp->pg_jobc == 0 && 1370 prop & SA_TTYSTOP)) 1371 break; /* == ignore */ 1372 pr->ps_xsig = signum; 1373 if (dolock) 1374 SCHED_LOCK(s); 1375 proc_stop(p, 1); 1376 if (dolock) 1377 SCHED_UNLOCK(s); 1378 break; 1379 } else if (prop & SA_IGNORE) { 1380 /* 1381 * Except for SIGCONT, shouldn't get here. 1382 * Default action is to ignore; drop it. 1383 */ 1384 break; /* == ignore */ 1385 } else 1386 goto keep; 1387 /* NOTREACHED */ 1388 case (long)SIG_IGN: 1389 /* 1390 * Masking above should prevent us ever trying 1391 * to take action on an ignored signal other 1392 * than SIGCONT, unless process is traced. 1393 */ 1394 if ((prop & SA_CONT) == 0 && 1395 (pr->ps_flags & PS_TRACED) == 0) 1396 printf("%s\n", __func__); 1397 break; /* == ignore */ 1398 default: 1399 /* 1400 * This signal has an action, let 1401 * postsig() process it. 1402 */ 1403 goto keep; 1404 } 1405 } 1406 /* NOTREACHED */ 1407 1408 keep: 1409 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1410 return (signum); 1411 } 1412 1413 /* 1414 * Put the argument process into the stopped state and notify the parent 1415 * via wakeup. Signals are handled elsewhere. The process must not be 1416 * on the run queue. 1417 */ 1418 void 1419 proc_stop(struct proc *p, int sw) 1420 { 1421 struct process *pr = p->p_p; 1422 1423 #ifdef MULTIPROCESSOR 1424 SCHED_ASSERT_LOCKED(); 1425 #endif 1426 1427 p->p_stat = SSTOP; 1428 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1429 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1430 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1431 /* 1432 * We need this soft interrupt to be handled fast. 1433 * Extra calls to softclock don't hurt. 1434 */ 1435 softintr_schedule(proc_stop_si); 1436 if (sw) 1437 mi_switch(); 1438 } 1439 1440 /* 1441 * Called from a soft interrupt to send signals to the parents of stopped 1442 * processes. 1443 * We can't do this in proc_stop because it's called with nasty locks held 1444 * and we would need recursive scheduler lock to deal with that. 1445 */ 1446 void 1447 proc_stop_sweep(void *v) 1448 { 1449 struct process *pr; 1450 1451 LIST_FOREACH(pr, &allprocess, ps_list) { 1452 if ((pr->ps_flags & PS_STOPPED) == 0) 1453 continue; 1454 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1455 1456 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1457 prsignal(pr->ps_pptr, SIGCHLD); 1458 wakeup(pr->ps_pptr); 1459 } 1460 } 1461 1462 /* 1463 * Take the action for the specified signal 1464 * from the current set of pending signals. 1465 */ 1466 void 1467 postsig(struct proc *p, int signum, struct sigctx *sctx) 1468 { 1469 u_long trapno; 1470 int mask, returnmask; 1471 siginfo_t si; 1472 union sigval sigval; 1473 int code; 1474 1475 KASSERT(signum != 0); 1476 1477 mask = sigmask(signum); 1478 atomic_clearbits_int(&p->p_siglist, mask); 1479 sigval.sival_ptr = NULL; 1480 1481 if (p->p_sisig != signum) { 1482 trapno = 0; 1483 code = SI_USER; 1484 sigval.sival_ptr = NULL; 1485 } else { 1486 trapno = p->p_sitrapno; 1487 code = p->p_sicode; 1488 sigval = p->p_sigval; 1489 } 1490 initsiginfo(&si, signum, trapno, code, sigval); 1491 1492 #ifdef KTRACE 1493 if (KTRPOINT(p, KTR_PSIG)) { 1494 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1495 p->p_oldmask : p->p_sigmask, code, &si); 1496 } 1497 #endif 1498 if (sctx->sig_action == SIG_DFL) { 1499 /* 1500 * Default action, where the default is to kill 1501 * the process. (Other cases were ignored above.) 1502 */ 1503 KERNEL_LOCK(); 1504 sigexit(p, signum); 1505 /* NOTREACHED */ 1506 } else { 1507 /* 1508 * If we get here, the signal must be caught. 1509 */ 1510 #ifdef DIAGNOSTIC 1511 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1512 panic("postsig action"); 1513 #endif 1514 /* 1515 * Set the new mask value and also defer further 1516 * occurrences of this signal. 1517 * 1518 * Special case: user has done a sigpause. Here the 1519 * current mask is not of interest, but rather the 1520 * mask from before the sigpause is what we want 1521 * restored after the signal processing is completed. 1522 */ 1523 if (p->p_flag & P_SIGSUSPEND) { 1524 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1525 returnmask = p->p_oldmask; 1526 } else { 1527 returnmask = p->p_sigmask; 1528 } 1529 if (p->p_sisig == signum) { 1530 p->p_sisig = 0; 1531 p->p_sitrapno = 0; 1532 p->p_sicode = SI_USER; 1533 p->p_sigval.sival_ptr = NULL; 1534 } 1535 1536 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1537 sctx->sig_info, sctx->sig_onstack)) { 1538 KERNEL_LOCK(); 1539 sigexit(p, SIGILL); 1540 /* NOTREACHED */ 1541 } 1542 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1543 } 1544 } 1545 1546 /* 1547 * Force the current process to exit with the specified signal, dumping core 1548 * if appropriate. We bypass the normal tests for masked and caught signals, 1549 * allowing unrecoverable failures to terminate the process without changing 1550 * signal state. Mark the accounting record with the signal termination. 1551 * If dumping core, save the signal number for the debugger. Calls exit and 1552 * does not return. 1553 */ 1554 void 1555 sigexit(struct proc *p, int signum) 1556 { 1557 /* Mark process as going away */ 1558 atomic_setbits_int(&p->p_flag, P_WEXIT); 1559 1560 p->p_p->ps_acflag |= AXSIG; 1561 if (sigprop[signum] & SA_CORE) { 1562 p->p_sisig = signum; 1563 1564 /* if there are other threads, pause them */ 1565 if (P_HASSIBLING(p)) 1566 single_thread_set(p, SINGLE_SUSPEND, 1); 1567 1568 if (coredump(p) == 0) 1569 signum |= WCOREFLAG; 1570 } 1571 exit1(p, 0, signum, EXIT_NORMAL); 1572 /* NOTREACHED */ 1573 } 1574 1575 /* 1576 * Send uncatchable SIGABRT for coredump. 1577 */ 1578 void 1579 sigabort(struct proc *p) 1580 { 1581 struct sigaction sa; 1582 1583 memset(&sa, 0, sizeof sa); 1584 sa.sa_handler = SIG_DFL; 1585 setsigvec(p, SIGABRT, &sa); 1586 atomic_clearbits_int(&p->p_sigmask, sigmask(SIGABRT)); 1587 psignal(p, SIGABRT); 1588 } 1589 1590 /* 1591 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1592 * thread, and 0 otherwise. 1593 */ 1594 int 1595 sigismasked(struct proc *p, int sig) 1596 { 1597 struct process *pr = p->p_p; 1598 int rv; 1599 1600 mtx_enter(&pr->ps_mtx); 1601 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1602 (p->p_sigmask & sigmask(sig)); 1603 mtx_leave(&pr->ps_mtx); 1604 1605 return !!rv; 1606 } 1607 1608 struct coredump_iostate { 1609 struct proc *io_proc; 1610 struct vnode *io_vp; 1611 struct ucred *io_cred; 1612 off_t io_offset; 1613 }; 1614 1615 /* 1616 * Dump core, into a file named "progname.core", unless the process was 1617 * setuid/setgid. 1618 */ 1619 int 1620 coredump(struct proc *p) 1621 { 1622 #ifdef SMALL_KERNEL 1623 return EPERM; 1624 #else 1625 struct process *pr = p->p_p; 1626 struct vnode *vp; 1627 struct ucred *cred = p->p_ucred; 1628 struct vmspace *vm = p->p_vmspace; 1629 struct nameidata nd; 1630 struct vattr vattr; 1631 struct coredump_iostate io; 1632 int error, len, incrash = 0; 1633 char *name; 1634 const char *dir = "/var/crash"; 1635 1636 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1637 1638 /* Don't dump if will exceed file size limit. */ 1639 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1640 return (EFBIG); 1641 1642 name = pool_get(&namei_pool, PR_WAITOK); 1643 1644 /* 1645 * If the process has inconsistent uids, nosuidcoredump 1646 * determines coredump placement policy. 1647 */ 1648 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1649 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1650 if (nosuidcoredump == 3) { 1651 /* 1652 * If the program directory does not exist, dumps of 1653 * that core will silently fail. 1654 */ 1655 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1656 dir, pr->ps_comm, pr->ps_pid); 1657 incrash = KERNELPATH; 1658 } else if (nosuidcoredump == 2) { 1659 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1660 dir, pr->ps_comm); 1661 incrash = KERNELPATH; 1662 } else { 1663 pool_put(&namei_pool, name); 1664 return (EPERM); 1665 } 1666 } else 1667 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1668 1669 if (len >= MAXPATHLEN) { 1670 pool_put(&namei_pool, name); 1671 return (EACCES); 1672 } 1673 1674 /* 1675 * Control the UID used to write out. The normal case uses 1676 * the real UID. If the sugid case is going to write into the 1677 * controlled directory, we do so as root. 1678 */ 1679 if (incrash == 0) { 1680 cred = crdup(cred); 1681 cred->cr_uid = cred->cr_ruid; 1682 cred->cr_gid = cred->cr_rgid; 1683 } else { 1684 if (p->p_fd->fd_rdir) { 1685 vrele(p->p_fd->fd_rdir); 1686 p->p_fd->fd_rdir = NULL; 1687 } 1688 p->p_ucred = crdup(p->p_ucred); 1689 crfree(cred); 1690 cred = p->p_ucred; 1691 crhold(cred); 1692 cred->cr_uid = 0; 1693 cred->cr_gid = 0; 1694 } 1695 1696 /* incrash should be 0 or KERNELPATH only */ 1697 NDINIT(&nd, 0, incrash, UIO_SYSSPACE, name, p); 1698 1699 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1700 S_IRUSR | S_IWUSR); 1701 1702 if (error) 1703 goto out; 1704 1705 /* 1706 * Don't dump to non-regular files, files with links, or files 1707 * owned by someone else. 1708 */ 1709 vp = nd.ni_vp; 1710 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1711 VOP_UNLOCK(vp); 1712 vn_close(vp, FWRITE, cred, p); 1713 goto out; 1714 } 1715 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1716 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1717 vattr.va_uid != cred->cr_uid) { 1718 error = EACCES; 1719 VOP_UNLOCK(vp); 1720 vn_close(vp, FWRITE, cred, p); 1721 goto out; 1722 } 1723 VATTR_NULL(&vattr); 1724 vattr.va_size = 0; 1725 VOP_SETATTR(vp, &vattr, cred, p); 1726 pr->ps_acflag |= ACORE; 1727 1728 io.io_proc = p; 1729 io.io_vp = vp; 1730 io.io_cred = cred; 1731 io.io_offset = 0; 1732 VOP_UNLOCK(vp); 1733 vref(vp); 1734 error = vn_close(vp, FWRITE, cred, p); 1735 if (error == 0) 1736 error = coredump_elf(p, &io); 1737 vrele(vp); 1738 out: 1739 crfree(cred); 1740 pool_put(&namei_pool, name); 1741 return (error); 1742 #endif 1743 } 1744 1745 #ifndef SMALL_KERNEL 1746 int 1747 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1748 { 1749 struct coredump_iostate *io = cookie; 1750 off_t coffset = 0; 1751 size_t csize; 1752 int chunk, error; 1753 1754 csize = len; 1755 do { 1756 if (sigmask(SIGKILL) & 1757 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1758 return (EINTR); 1759 1760 /* Rest of the loop sleeps with lock held, so... */ 1761 yield(); 1762 1763 chunk = MIN(csize, MAXPHYS); 1764 error = vn_rdwr(UIO_WRITE, io->io_vp, 1765 (caddr_t)data + coffset, chunk, 1766 io->io_offset + coffset, segflg, 1767 IO_UNIT, io->io_cred, NULL, io->io_proc); 1768 if (error) { 1769 struct process *pr = io->io_proc->p_p; 1770 1771 if (error == ENOSPC) 1772 log(LOG_ERR, 1773 "coredump of %s(%d) failed, filesystem full\n", 1774 pr->ps_comm, pr->ps_pid); 1775 else 1776 log(LOG_ERR, 1777 "coredump of %s(%d), write failed: errno %d\n", 1778 pr->ps_comm, pr->ps_pid, error); 1779 return (error); 1780 } 1781 1782 coffset += chunk; 1783 csize -= chunk; 1784 } while (csize > 0); 1785 1786 io->io_offset += len; 1787 return (0); 1788 } 1789 1790 void 1791 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1792 { 1793 struct coredump_iostate *io = cookie; 1794 1795 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1796 } 1797 1798 #endif /* !SMALL_KERNEL */ 1799 1800 /* 1801 * Nonexistent system call-- signal process (may want to handle it). 1802 * Flag error in case process won't see signal immediately (blocked or ignored). 1803 */ 1804 int 1805 sys_nosys(struct proc *p, void *v, register_t *retval) 1806 { 1807 ptsignal(p, SIGSYS, STHREAD); 1808 return (ENOSYS); 1809 } 1810 1811 int 1812 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1813 { 1814 static int sigwaitsleep; 1815 struct sys___thrsigdivert_args /* { 1816 syscallarg(sigset_t) sigmask; 1817 syscallarg(siginfo_t *) info; 1818 syscallarg(const struct timespec *) timeout; 1819 } */ *uap = v; 1820 struct sigctx ctx; 1821 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1822 siginfo_t si; 1823 uint64_t nsecs = INFSLP; 1824 int timeinvalid = 0; 1825 int error = 0; 1826 1827 memset(&si, 0, sizeof(si)); 1828 1829 if (SCARG(uap, timeout) != NULL) { 1830 struct timespec ts; 1831 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1832 return (error); 1833 #ifdef KTRACE 1834 if (KTRPOINT(p, KTR_STRUCT)) 1835 ktrreltimespec(p, &ts); 1836 #endif 1837 if (!timespecisvalid(&ts)) 1838 timeinvalid = 1; 1839 else 1840 nsecs = TIMESPEC_TO_NSEC(&ts); 1841 } 1842 1843 dosigsuspend(p, p->p_sigmask &~ mask); 1844 for (;;) { 1845 si.si_signo = cursig(p, &ctx); 1846 if (si.si_signo != 0) { 1847 sigset_t smask = sigmask(si.si_signo); 1848 if (smask & mask) { 1849 atomic_clearbits_int(&p->p_siglist, smask); 1850 error = 0; 1851 break; 1852 } 1853 } 1854 1855 /* per-POSIX, delay this error until after the above */ 1856 if (timeinvalid) 1857 error = EINVAL; 1858 /* per-POSIX, return immediately if timeout is zero-valued */ 1859 if (nsecs == 0) 1860 error = EAGAIN; 1861 1862 if (error != 0) 1863 break; 1864 1865 error = tsleep_nsec(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1866 nsecs); 1867 } 1868 1869 if (error == 0) { 1870 *retval = si.si_signo; 1871 if (SCARG(uap, info) != NULL) { 1872 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1873 #ifdef KTRACE 1874 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1875 ktrsiginfo(p, &si); 1876 #endif 1877 } 1878 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1879 /* 1880 * Restarting is wrong if there's a timeout, as it'll be 1881 * for the same interval again 1882 */ 1883 error = EINTR; 1884 } 1885 1886 return (error); 1887 } 1888 1889 void 1890 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1891 { 1892 memset(si, 0, sizeof(*si)); 1893 1894 si->si_signo = sig; 1895 si->si_code = code; 1896 if (code == SI_USER) { 1897 si->si_value = val; 1898 } else { 1899 switch (sig) { 1900 case SIGSEGV: 1901 case SIGILL: 1902 case SIGBUS: 1903 case SIGFPE: 1904 si->si_addr = val.sival_ptr; 1905 si->si_trapno = trapno; 1906 break; 1907 case SIGXFSZ: 1908 break; 1909 } 1910 } 1911 } 1912 1913 int 1914 filt_sigattach(struct knote *kn) 1915 { 1916 struct process *pr = curproc->p_p; 1917 int s; 1918 1919 if (kn->kn_id >= NSIG) 1920 return EINVAL; 1921 1922 kn->kn_ptr.p_process = pr; 1923 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1924 1925 s = splhigh(); 1926 klist_insert_locked(&pr->ps_klist, kn); 1927 splx(s); 1928 1929 return (0); 1930 } 1931 1932 void 1933 filt_sigdetach(struct knote *kn) 1934 { 1935 struct process *pr = kn->kn_ptr.p_process; 1936 int s; 1937 1938 s = splhigh(); 1939 klist_remove_locked(&pr->ps_klist, kn); 1940 splx(s); 1941 } 1942 1943 /* 1944 * signal knotes are shared with proc knotes, so we apply a mask to 1945 * the hint in order to differentiate them from process hints. This 1946 * could be avoided by using a signal-specific knote list, but probably 1947 * isn't worth the trouble. 1948 */ 1949 int 1950 filt_signal(struct knote *kn, long hint) 1951 { 1952 1953 if (hint & NOTE_SIGNAL) { 1954 hint &= ~NOTE_SIGNAL; 1955 1956 if (kn->kn_id == hint) 1957 kn->kn_data++; 1958 } 1959 return (kn->kn_data != 0); 1960 } 1961 1962 void 1963 userret(struct proc *p) 1964 { 1965 struct sigctx ctx; 1966 int signum; 1967 1968 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1969 if (p->p_flag & P_PROFPEND) { 1970 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1971 KERNEL_LOCK(); 1972 psignal(p, SIGPROF); 1973 KERNEL_UNLOCK(); 1974 } 1975 if (p->p_flag & P_ALRMPEND) { 1976 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1977 KERNEL_LOCK(); 1978 psignal(p, SIGVTALRM); 1979 KERNEL_UNLOCK(); 1980 } 1981 1982 if (SIGPENDING(p) != 0) { 1983 while ((signum = cursig(p, &ctx)) != 0) 1984 postsig(p, signum, &ctx); 1985 } 1986 1987 /* 1988 * If P_SIGSUSPEND is still set here, then we still need to restore 1989 * the original sigmask before returning to userspace. Also, this 1990 * might unmask some pending signals, so we need to check a second 1991 * time for signals to post. 1992 */ 1993 if (p->p_flag & P_SIGSUSPEND) { 1994 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1995 p->p_sigmask = p->p_oldmask; 1996 1997 while ((signum = cursig(p, &ctx)) != 0) 1998 postsig(p, signum, &ctx); 1999 } 2000 2001 if (p->p_flag & P_SUSPSINGLE) 2002 single_thread_check(p, 0); 2003 2004 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2005 2006 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2007 } 2008 2009 int 2010 single_thread_check_locked(struct proc *p, int deep, int s) 2011 { 2012 struct process *pr = p->p_p; 2013 2014 SCHED_ASSERT_LOCKED(); 2015 2016 if (pr->ps_single != NULL && pr->ps_single != p) { 2017 do { 2018 /* if we're in deep, we need to unwind to the edge */ 2019 if (deep) { 2020 if (pr->ps_flags & PS_SINGLEUNWIND) 2021 return (ERESTART); 2022 if (pr->ps_flags & PS_SINGLEEXIT) 2023 return (EINTR); 2024 } 2025 2026 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2027 wakeup(&pr->ps_singlecount); 2028 2029 if (pr->ps_flags & PS_SINGLEEXIT) { 2030 SCHED_UNLOCK(s); 2031 KERNEL_LOCK(); 2032 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2033 /* NOTREACHED */ 2034 } 2035 2036 /* not exiting and don't need to unwind, so suspend */ 2037 p->p_stat = SSTOP; 2038 mi_switch(); 2039 } while (pr->ps_single != NULL); 2040 } 2041 2042 return (0); 2043 } 2044 2045 int 2046 single_thread_check(struct proc *p, int deep) 2047 { 2048 int s, error; 2049 2050 SCHED_LOCK(s); 2051 error = single_thread_check_locked(p, deep, s); 2052 SCHED_UNLOCK(s); 2053 2054 return error; 2055 } 2056 2057 /* 2058 * Stop other threads in the process. The mode controls how and 2059 * where the other threads should stop: 2060 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 2061 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 2062 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2063 * or released as with SINGLE_SUSPEND 2064 * - SINGLE_EXIT: unwind to kernel boundary and exit 2065 */ 2066 int 2067 single_thread_set(struct proc *p, enum single_thread_mode mode, int wait) 2068 { 2069 struct process *pr = p->p_p; 2070 struct proc *q; 2071 int error, s; 2072 2073 KASSERT(curproc == p); 2074 2075 SCHED_LOCK(s); 2076 error = single_thread_check_locked(p, (mode == SINGLE_UNWIND), s); 2077 if (error) { 2078 SCHED_UNLOCK(s); 2079 return error; 2080 } 2081 2082 switch (mode) { 2083 case SINGLE_SUSPEND: 2084 break; 2085 case SINGLE_UNWIND: 2086 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2087 break; 2088 case SINGLE_EXIT: 2089 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2090 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2091 break; 2092 #ifdef DIAGNOSTIC 2093 default: 2094 panic("single_thread_mode = %d", mode); 2095 #endif 2096 } 2097 pr->ps_singlecount = 0; 2098 membar_producer(); 2099 pr->ps_single = p; 2100 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2101 if (q == p) 2102 continue; 2103 if (q->p_flag & P_WEXIT) { 2104 if (mode == SINGLE_EXIT) { 2105 if (q->p_stat == SSTOP) { 2106 setrunnable(q); 2107 atomic_inc_int(&pr->ps_singlecount); 2108 } 2109 } 2110 continue; 2111 } 2112 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2113 switch (q->p_stat) { 2114 case SIDL: 2115 case SRUN: 2116 atomic_inc_int(&pr->ps_singlecount); 2117 break; 2118 case SSLEEP: 2119 /* if it's not interruptible, then just have to wait */ 2120 if (q->p_flag & P_SINTR) { 2121 /* merely need to suspend? just stop it */ 2122 if (mode == SINGLE_SUSPEND) { 2123 q->p_stat = SSTOP; 2124 break; 2125 } 2126 /* need to unwind or exit, so wake it */ 2127 setrunnable(q); 2128 } 2129 atomic_inc_int(&pr->ps_singlecount); 2130 break; 2131 case SSTOP: 2132 if (mode == SINGLE_EXIT) { 2133 setrunnable(q); 2134 atomic_inc_int(&pr->ps_singlecount); 2135 } 2136 break; 2137 case SDEAD: 2138 break; 2139 case SONPROC: 2140 atomic_inc_int(&pr->ps_singlecount); 2141 signotify(q); 2142 break; 2143 } 2144 } 2145 SCHED_UNLOCK(s); 2146 2147 if (wait) 2148 single_thread_wait(pr, 1); 2149 2150 return 0; 2151 } 2152 2153 /* 2154 * Wait for other threads to stop. If recheck is false then the function 2155 * returns non-zero if the caller needs to restart the check else 0 is 2156 * returned. If recheck is true the return value is always 0. 2157 */ 2158 int 2159 single_thread_wait(struct process *pr, int recheck) 2160 { 2161 struct sleep_state sls; 2162 int wait; 2163 2164 /* wait until they're all suspended */ 2165 wait = pr->ps_singlecount > 0; 2166 while (wait) { 2167 sleep_setup(&sls, &pr->ps_singlecount, PWAIT, "suspend", 0); 2168 wait = pr->ps_singlecount > 0; 2169 sleep_finish(&sls, wait); 2170 if (!recheck) 2171 break; 2172 } 2173 2174 return wait; 2175 } 2176 2177 void 2178 single_thread_clear(struct proc *p, int flag) 2179 { 2180 struct process *pr = p->p_p; 2181 struct proc *q; 2182 int s; 2183 2184 KASSERT(pr->ps_single == p); 2185 KASSERT(curproc == p); 2186 2187 SCHED_LOCK(s); 2188 pr->ps_single = NULL; 2189 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2190 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2191 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2192 continue; 2193 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2194 2195 /* 2196 * if the thread was only stopped for single threading 2197 * then clearing that either makes it runnable or puts 2198 * it back into some sleep queue 2199 */ 2200 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2201 if (q->p_wchan == NULL) 2202 setrunnable(q); 2203 else 2204 q->p_stat = SSLEEP; 2205 } 2206 } 2207 SCHED_UNLOCK(s); 2208 } 2209 2210 void 2211 sigio_del(struct sigiolst *rmlist) 2212 { 2213 struct sigio *sigio; 2214 2215 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2216 LIST_REMOVE(sigio, sio_pgsigio); 2217 crfree(sigio->sio_ucred); 2218 free(sigio, M_SIGIO, sizeof(*sigio)); 2219 } 2220 } 2221 2222 void 2223 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2224 { 2225 struct sigio *sigio; 2226 2227 MUTEX_ASSERT_LOCKED(&sigio_lock); 2228 2229 sigio = sir->sir_sigio; 2230 if (sigio != NULL) { 2231 KASSERT(sigio->sio_myref == sir); 2232 sir->sir_sigio = NULL; 2233 2234 if (sigio->sio_pgid > 0) 2235 sigio->sio_proc = NULL; 2236 else 2237 sigio->sio_pgrp = NULL; 2238 LIST_REMOVE(sigio, sio_pgsigio); 2239 2240 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2241 } 2242 } 2243 2244 void 2245 sigio_free(struct sigio_ref *sir) 2246 { 2247 struct sigiolst rmlist; 2248 2249 if (sir->sir_sigio == NULL) 2250 return; 2251 2252 LIST_INIT(&rmlist); 2253 2254 mtx_enter(&sigio_lock); 2255 sigio_unlink(sir, &rmlist); 2256 mtx_leave(&sigio_lock); 2257 2258 sigio_del(&rmlist); 2259 } 2260 2261 void 2262 sigio_freelist(struct sigiolst *sigiolst) 2263 { 2264 struct sigiolst rmlist; 2265 struct sigio *sigio; 2266 2267 if (LIST_EMPTY(sigiolst)) 2268 return; 2269 2270 LIST_INIT(&rmlist); 2271 2272 mtx_enter(&sigio_lock); 2273 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2274 sigio_unlink(sigio->sio_myref, &rmlist); 2275 mtx_leave(&sigio_lock); 2276 2277 sigio_del(&rmlist); 2278 } 2279 2280 int 2281 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2282 { 2283 struct sigiolst rmlist; 2284 struct proc *p = curproc; 2285 struct pgrp *pgrp = NULL; 2286 struct process *pr = NULL; 2287 struct sigio *sigio; 2288 int error; 2289 pid_t pgid = *(int *)data; 2290 2291 if (pgid == 0) { 2292 sigio_free(sir); 2293 return (0); 2294 } 2295 2296 if (cmd == TIOCSPGRP) { 2297 if (pgid < 0) 2298 return (EINVAL); 2299 pgid = -pgid; 2300 } 2301 2302 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2303 sigio->sio_pgid = pgid; 2304 sigio->sio_ucred = crhold(p->p_ucred); 2305 sigio->sio_myref = sir; 2306 2307 LIST_INIT(&rmlist); 2308 2309 /* 2310 * The kernel lock, and not sleeping between prfind()/pgfind() and 2311 * linking of the sigio ensure that the process or process group does 2312 * not disappear unexpectedly. 2313 */ 2314 KERNEL_LOCK(); 2315 mtx_enter(&sigio_lock); 2316 2317 if (pgid > 0) { 2318 pr = prfind(pgid); 2319 if (pr == NULL) { 2320 error = ESRCH; 2321 goto fail; 2322 } 2323 2324 /* 2325 * Policy - Don't allow a process to FSETOWN a process 2326 * in another session. 2327 * 2328 * Remove this test to allow maximum flexibility or 2329 * restrict FSETOWN to the current process or process 2330 * group for maximum safety. 2331 */ 2332 if (pr->ps_session != p->p_p->ps_session) { 2333 error = EPERM; 2334 goto fail; 2335 } 2336 2337 if ((pr->ps_flags & PS_EXITING) != 0) { 2338 error = ESRCH; 2339 goto fail; 2340 } 2341 } else /* if (pgid < 0) */ { 2342 pgrp = pgfind(-pgid); 2343 if (pgrp == NULL) { 2344 error = ESRCH; 2345 goto fail; 2346 } 2347 2348 /* 2349 * Policy - Don't allow a process to FSETOWN a process 2350 * in another session. 2351 * 2352 * Remove this test to allow maximum flexibility or 2353 * restrict FSETOWN to the current process or process 2354 * group for maximum safety. 2355 */ 2356 if (pgrp->pg_session != p->p_p->ps_session) { 2357 error = EPERM; 2358 goto fail; 2359 } 2360 } 2361 2362 if (pgid > 0) { 2363 sigio->sio_proc = pr; 2364 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2365 } else { 2366 sigio->sio_pgrp = pgrp; 2367 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2368 } 2369 2370 sigio_unlink(sir, &rmlist); 2371 sir->sir_sigio = sigio; 2372 2373 mtx_leave(&sigio_lock); 2374 KERNEL_UNLOCK(); 2375 2376 sigio_del(&rmlist); 2377 2378 return (0); 2379 2380 fail: 2381 mtx_leave(&sigio_lock); 2382 KERNEL_UNLOCK(); 2383 2384 crfree(sigio->sio_ucred); 2385 free(sigio, M_SIGIO, sizeof(*sigio)); 2386 2387 return (error); 2388 } 2389 2390 void 2391 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2392 { 2393 struct sigio *sigio; 2394 pid_t pgid = 0; 2395 2396 mtx_enter(&sigio_lock); 2397 sigio = sir->sir_sigio; 2398 if (sigio != NULL) 2399 pgid = sigio->sio_pgid; 2400 mtx_leave(&sigio_lock); 2401 2402 if (cmd == TIOCGPGRP) 2403 pgid = -pgid; 2404 2405 *(int *)data = pgid; 2406 } 2407 2408 void 2409 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2410 { 2411 struct sigiolst rmlist; 2412 struct sigio *newsigio, *sigio; 2413 2414 sigio_free(dst); 2415 2416 if (src->sir_sigio == NULL) 2417 return; 2418 2419 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2420 LIST_INIT(&rmlist); 2421 2422 mtx_enter(&sigio_lock); 2423 2424 sigio = src->sir_sigio; 2425 if (sigio == NULL) { 2426 mtx_leave(&sigio_lock); 2427 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2428 return; 2429 } 2430 2431 newsigio->sio_pgid = sigio->sio_pgid; 2432 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2433 newsigio->sio_myref = dst; 2434 if (newsigio->sio_pgid > 0) { 2435 newsigio->sio_proc = sigio->sio_proc; 2436 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2437 sio_pgsigio); 2438 } else { 2439 newsigio->sio_pgrp = sigio->sio_pgrp; 2440 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2441 sio_pgsigio); 2442 } 2443 2444 sigio_unlink(dst, &rmlist); 2445 dst->sir_sigio = newsigio; 2446 2447 mtx_leave(&sigio_lock); 2448 2449 sigio_del(&rmlist); 2450 } 2451