1 /* $OpenBSD: kern_sig.c,v 1.312 2023/08/13 15:53:31 claudio 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_locked(&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 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1157 p->p_stat = SSLEEP; 1158 goto out; 1159 } 1160 1161 if (prop & SA_STOP) { 1162 /* 1163 * Already stopped, don't need to stop again. 1164 * (If we did the shell could get confused.) 1165 */ 1166 mask = 0; 1167 goto out; 1168 } 1169 1170 /* 1171 * If process is sleeping interruptibly, then simulate a 1172 * wakeup so that when it is continued, it will be made 1173 * runnable and can look at the signal. But don't make 1174 * the process runnable, leave it stopped. 1175 */ 1176 if (p->p_flag & P_SINTR) 1177 unsleep(p); 1178 goto out; 1179 1180 case SONPROC: 1181 /* set siglist before issuing the ast */ 1182 atomic_setbits_int(siglist, mask); 1183 mask = 0; 1184 signotify(p); 1185 /* FALLTHROUGH */ 1186 default: 1187 /* 1188 * SRUN, SIDL, SDEAD do nothing with the signal, 1189 * other than kicking ourselves if we are running. 1190 * It will either never be noticed, or noticed very soon. 1191 */ 1192 goto out; 1193 } 1194 /* NOTREACHED */ 1195 1196 runfast: 1197 /* 1198 * Raise priority to at least PUSER. 1199 */ 1200 if (p->p_usrpri > PUSER) 1201 p->p_usrpri = PUSER; 1202 run: 1203 setrunnable(p); 1204 out: 1205 /* finally adjust siglist */ 1206 if (mask) 1207 atomic_setbits_int(siglist, mask); 1208 SCHED_UNLOCK(s); 1209 if (wakeparent) 1210 wakeup(pr->ps_pptr); 1211 } 1212 1213 /* fill the signal context which should be used by postsig() and issignal() */ 1214 void 1215 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1216 { 1217 struct sigacts *ps = p->p_p->ps_sigacts; 1218 sigset_t mask; 1219 1220 mtx_enter(&p->p_p->ps_mtx); 1221 mask = sigmask(signum); 1222 sctx->sig_action = ps->ps_sigact[signum]; 1223 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1224 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1225 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1226 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1227 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1228 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1229 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1230 mtx_leave(&p->p_p->ps_mtx); 1231 } 1232 1233 /* 1234 * Determine signal that should be delivered to process p, the current 1235 * process, 0 if none. 1236 * 1237 * If the current process has received a signal (should be caught or cause 1238 * termination, should interrupt current syscall), return the signal number. 1239 * Stop signals with default action are processed immediately, then cleared; 1240 * they aren't returned. This is checked after each entry to the system for 1241 * a syscall or trap. The normal call sequence is 1242 * 1243 * while (signum = cursig(curproc, &ctx)) 1244 * postsig(signum, &ctx); 1245 * 1246 * Assumes that if the P_SINTR flag is set, we're holding both the 1247 * kernel and scheduler locks. 1248 */ 1249 int 1250 cursig(struct proc *p, struct sigctx *sctx) 1251 { 1252 struct process *pr = p->p_p; 1253 int signum, mask, prop; 1254 int dolock = (p->p_flag & P_SINTR) == 0; 1255 sigset_t ps_siglist; 1256 int s; 1257 1258 KASSERT(p == curproc); 1259 1260 for (;;) { 1261 ps_siglist = READ_ONCE(pr->ps_siglist); 1262 membar_consumer(); 1263 mask = SIGPENDING(p); 1264 if (pr->ps_flags & PS_PPWAIT) 1265 mask &= ~STOPSIGMASK; 1266 if (mask == 0) /* no signal to send */ 1267 return (0); 1268 signum = ffs((long)mask); 1269 mask = sigmask(signum); 1270 1271 /* take the signal! */ 1272 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1273 ps_siglist & ~mask) != ps_siglist) { 1274 /* lost race taking the process signal, restart */ 1275 continue; 1276 } 1277 atomic_clearbits_int(&p->p_siglist, mask); 1278 setsigctx(p, signum, sctx); 1279 1280 /* 1281 * We should see pending but ignored signals 1282 * only if PS_TRACED was on when they were posted. 1283 */ 1284 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1285 continue; 1286 1287 /* 1288 * If traced, always stop, and stay stopped until released 1289 * by the debugger. If our parent process is waiting for 1290 * us, don't hang as we could deadlock. 1291 */ 1292 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1293 signum != SIGKILL) { 1294 single_thread_set(p, SINGLE_SUSPEND, 0); 1295 pr->ps_xsig = signum; 1296 1297 if (dolock) 1298 SCHED_LOCK(s); 1299 proc_stop(p, 1); 1300 if (dolock) 1301 SCHED_UNLOCK(s); 1302 1303 /* 1304 * re-take the signal before releasing 1305 * the other threads. Must check the continue 1306 * conditions below and only take the signal if 1307 * those are not true. 1308 */ 1309 signum = pr->ps_xsig; 1310 mask = sigmask(signum); 1311 setsigctx(p, signum, sctx); 1312 if (!((pr->ps_flags & PS_TRACED) == 0 || 1313 signum == 0 || 1314 (p->p_sigmask & mask) != 0)) { 1315 atomic_clearbits_int(&p->p_siglist, mask); 1316 atomic_clearbits_int(&pr->ps_siglist, mask); 1317 } 1318 1319 single_thread_clear(p, 0); 1320 1321 /* 1322 * If we are no longer being traced, or the parent 1323 * didn't give us a signal, look for more signals. 1324 */ 1325 if ((pr->ps_flags & PS_TRACED) == 0 || 1326 signum == 0) 1327 continue; 1328 1329 /* 1330 * If the new signal is being masked, look for other 1331 * signals. 1332 */ 1333 if ((p->p_sigmask & mask) != 0) 1334 continue; 1335 1336 } 1337 1338 prop = sigprop[signum]; 1339 1340 /* 1341 * Decide whether the signal should be returned. 1342 * Return the signal's number, or fall through 1343 * to clear it from the pending mask. 1344 */ 1345 switch ((long)sctx->sig_action) { 1346 case (long)SIG_DFL: 1347 /* 1348 * Don't take default actions on system processes. 1349 */ 1350 if (pr->ps_pid <= 1) { 1351 #ifdef DIAGNOSTIC 1352 /* 1353 * Are you sure you want to ignore SIGSEGV 1354 * in init? XXX 1355 */ 1356 printf("Process (pid %d) got signal" 1357 " %d\n", pr->ps_pid, signum); 1358 #endif 1359 break; /* == ignore */ 1360 } 1361 /* 1362 * If there is a pending stop signal to process 1363 * with default action, stop here, 1364 * then clear the signal. However, 1365 * if process is member of an orphaned 1366 * process group, ignore tty stop signals. 1367 */ 1368 if (prop & SA_STOP) { 1369 if (pr->ps_flags & PS_TRACED || 1370 (pr->ps_pgrp->pg_jobc == 0 && 1371 prop & SA_TTYSTOP)) 1372 break; /* == ignore */ 1373 pr->ps_xsig = signum; 1374 if (dolock) 1375 SCHED_LOCK(s); 1376 proc_stop(p, 1); 1377 if (dolock) 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_SUSPEND, 1); 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 { 1755 struct coredump_iostate *io = cookie; 1756 off_t coffset = 0; 1757 size_t csize; 1758 int chunk, error; 1759 1760 csize = len; 1761 do { 1762 if (sigmask(SIGKILL) & 1763 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1764 return (EINTR); 1765 1766 /* Rest of the loop sleeps with lock held, so... */ 1767 yield(); 1768 1769 chunk = MIN(csize, MAXPHYS); 1770 error = vn_rdwr(UIO_WRITE, io->io_vp, 1771 (caddr_t)data + coffset, chunk, 1772 io->io_offset + coffset, segflg, 1773 IO_UNIT, io->io_cred, NULL, io->io_proc); 1774 if (error) { 1775 struct process *pr = io->io_proc->p_p; 1776 1777 if (error == ENOSPC) 1778 log(LOG_ERR, 1779 "coredump of %s(%d) failed, filesystem full\n", 1780 pr->ps_comm, pr->ps_pid); 1781 else 1782 log(LOG_ERR, 1783 "coredump of %s(%d), write failed: errno %d\n", 1784 pr->ps_comm, pr->ps_pid, error); 1785 return (error); 1786 } 1787 1788 coffset += chunk; 1789 csize -= chunk; 1790 } while (csize > 0); 1791 1792 io->io_offset += len; 1793 return (0); 1794 } 1795 1796 void 1797 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1798 { 1799 struct coredump_iostate *io = cookie; 1800 1801 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1802 } 1803 1804 #endif /* !SMALL_KERNEL */ 1805 1806 /* 1807 * Nonexistent system call-- signal process (may want to handle it). 1808 * Flag error in case process won't see signal immediately (blocked or ignored). 1809 */ 1810 int 1811 sys_nosys(struct proc *p, void *v, register_t *retval) 1812 { 1813 ptsignal(p, SIGSYS, STHREAD); 1814 return (ENOSYS); 1815 } 1816 1817 int 1818 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1819 { 1820 static int sigwaitsleep; 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(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1872 nsecs); 1873 } 1874 1875 if (error == 0) { 1876 *retval = si.si_signo; 1877 if (SCARG(uap, info) != NULL) { 1878 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1879 #ifdef KTRACE 1880 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1881 ktrsiginfo(p, &si); 1882 #endif 1883 } 1884 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1885 /* 1886 * Restarting is wrong if there's a timeout, as it'll be 1887 * for the same interval again 1888 */ 1889 error = EINTR; 1890 } 1891 1892 return (error); 1893 } 1894 1895 void 1896 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1897 { 1898 memset(si, 0, sizeof(*si)); 1899 1900 si->si_signo = sig; 1901 si->si_code = code; 1902 if (code == SI_USER) { 1903 si->si_value = val; 1904 } else { 1905 switch (sig) { 1906 case SIGSEGV: 1907 case SIGILL: 1908 case SIGBUS: 1909 case SIGFPE: 1910 si->si_addr = val.sival_ptr; 1911 si->si_trapno = trapno; 1912 break; 1913 case SIGXFSZ: 1914 break; 1915 } 1916 } 1917 } 1918 1919 int 1920 filt_sigattach(struct knote *kn) 1921 { 1922 struct process *pr = curproc->p_p; 1923 int s; 1924 1925 if (kn->kn_id >= NSIG) 1926 return EINVAL; 1927 1928 kn->kn_ptr.p_process = pr; 1929 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1930 1931 s = splhigh(); 1932 klist_insert_locked(&pr->ps_klist, kn); 1933 splx(s); 1934 1935 return (0); 1936 } 1937 1938 void 1939 filt_sigdetach(struct knote *kn) 1940 { 1941 struct process *pr = kn->kn_ptr.p_process; 1942 int s; 1943 1944 s = splhigh(); 1945 klist_remove_locked(&pr->ps_klist, kn); 1946 splx(s); 1947 } 1948 1949 /* 1950 * signal knotes are shared with proc knotes, so we apply a mask to 1951 * the hint in order to differentiate them from process hints. This 1952 * could be avoided by using a signal-specific knote list, but probably 1953 * isn't worth the trouble. 1954 */ 1955 int 1956 filt_signal(struct knote *kn, long hint) 1957 { 1958 1959 if (hint & NOTE_SIGNAL) { 1960 hint &= ~NOTE_SIGNAL; 1961 1962 if (kn->kn_id == hint) 1963 kn->kn_data++; 1964 } 1965 return (kn->kn_data != 0); 1966 } 1967 1968 void 1969 userret(struct proc *p) 1970 { 1971 struct sigctx ctx; 1972 int signum; 1973 1974 if (p->p_flag & P_SUSPSINGLE) 1975 single_thread_check(p, 0); 1976 1977 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1978 if (p->p_flag & P_PROFPEND) { 1979 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1980 KERNEL_LOCK(); 1981 psignal(p, SIGPROF); 1982 KERNEL_UNLOCK(); 1983 } 1984 if (p->p_flag & P_ALRMPEND) { 1985 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1986 KERNEL_LOCK(); 1987 psignal(p, SIGVTALRM); 1988 KERNEL_UNLOCK(); 1989 } 1990 1991 if (SIGPENDING(p) != 0) { 1992 while ((signum = cursig(p, &ctx)) != 0) 1993 postsig(p, signum, &ctx); 1994 } 1995 1996 /* 1997 * If P_SIGSUSPEND is still set here, then we still need to restore 1998 * the original sigmask before returning to userspace. Also, this 1999 * might unmask some pending signals, so we need to check a second 2000 * time for signals to post. 2001 */ 2002 if (p->p_flag & P_SIGSUSPEND) { 2003 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2004 p->p_sigmask = p->p_oldmask; 2005 2006 while ((signum = cursig(p, &ctx)) != 0) 2007 postsig(p, signum, &ctx); 2008 } 2009 2010 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2011 2012 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2013 } 2014 2015 int 2016 single_thread_check_locked(struct proc *p, int deep, int s) 2017 { 2018 struct process *pr = p->p_p; 2019 2020 SCHED_ASSERT_LOCKED(); 2021 2022 if (pr->ps_single == NULL || pr->ps_single == p) 2023 return (0); 2024 2025 do { 2026 /* if we're in deep, we need to unwind to the edge */ 2027 if (deep) { 2028 if (pr->ps_flags & PS_SINGLEUNWIND) 2029 return (ERESTART); 2030 if (pr->ps_flags & PS_SINGLEEXIT) 2031 return (EINTR); 2032 } 2033 2034 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2035 wakeup(&pr->ps_singlecount); 2036 2037 if (pr->ps_flags & PS_SINGLEEXIT) { 2038 SCHED_UNLOCK(s); 2039 KERNEL_LOCK(); 2040 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2041 /* NOTREACHED */ 2042 } 2043 2044 /* not exiting and don't need to unwind, so suspend */ 2045 p->p_stat = SSTOP; 2046 mi_switch(); 2047 } while (pr->ps_single != NULL); 2048 2049 return (0); 2050 } 2051 2052 int 2053 single_thread_check(struct proc *p, int deep) 2054 { 2055 int s, error; 2056 2057 SCHED_LOCK(s); 2058 error = single_thread_check_locked(p, deep, s); 2059 SCHED_UNLOCK(s); 2060 2061 return error; 2062 } 2063 2064 /* 2065 * Stop other threads in the process. The mode controls how and 2066 * where the other threads should stop: 2067 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 2068 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 2069 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2070 * or released as with SINGLE_SUSPEND 2071 * - SINGLE_EXIT: unwind to kernel boundary and exit 2072 */ 2073 int 2074 single_thread_set(struct proc *p, enum single_thread_mode mode, int wait) 2075 { 2076 struct process *pr = p->p_p; 2077 struct proc *q; 2078 int error, s; 2079 2080 KASSERT(curproc == p); 2081 2082 SCHED_LOCK(s); 2083 error = single_thread_check_locked(p, (mode == SINGLE_UNWIND), s); 2084 if (error) { 2085 SCHED_UNLOCK(s); 2086 return error; 2087 } 2088 2089 switch (mode) { 2090 case SINGLE_SUSPEND: 2091 break; 2092 case SINGLE_UNWIND: 2093 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2094 break; 2095 case SINGLE_EXIT: 2096 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2097 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2098 break; 2099 #ifdef DIAGNOSTIC 2100 default: 2101 panic("single_thread_mode = %d", mode); 2102 #endif 2103 } 2104 pr->ps_singlecount = 0; 2105 membar_producer(); 2106 pr->ps_single = p; 2107 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2108 if (q == p) 2109 continue; 2110 if (q->p_flag & P_WEXIT) { 2111 if (mode == SINGLE_EXIT) { 2112 if (q->p_stat == SSTOP) { 2113 setrunnable(q); 2114 atomic_inc_int(&pr->ps_singlecount); 2115 } 2116 } 2117 continue; 2118 } 2119 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2120 switch (q->p_stat) { 2121 case SIDL: 2122 case SRUN: 2123 atomic_inc_int(&pr->ps_singlecount); 2124 break; 2125 case SSLEEP: 2126 /* if it's not interruptible, then just have to wait */ 2127 if (q->p_flag & P_SINTR) { 2128 /* merely need to suspend? just stop it */ 2129 if (mode == SINGLE_SUSPEND) { 2130 q->p_stat = SSTOP; 2131 break; 2132 } 2133 /* need to unwind or exit, so wake it */ 2134 setrunnable(q); 2135 } 2136 atomic_inc_int(&pr->ps_singlecount); 2137 break; 2138 case SSTOP: 2139 if (mode == SINGLE_EXIT) { 2140 setrunnable(q); 2141 atomic_inc_int(&pr->ps_singlecount); 2142 } 2143 break; 2144 case SDEAD: 2145 break; 2146 case SONPROC: 2147 atomic_inc_int(&pr->ps_singlecount); 2148 signotify(q); 2149 break; 2150 } 2151 } 2152 SCHED_UNLOCK(s); 2153 2154 if (wait) 2155 single_thread_wait(pr, 1); 2156 2157 return 0; 2158 } 2159 2160 /* 2161 * Wait for other threads to stop. If recheck is false then the function 2162 * returns non-zero if the caller needs to restart the check else 0 is 2163 * returned. If recheck is true the return value is always 0. 2164 */ 2165 int 2166 single_thread_wait(struct process *pr, int recheck) 2167 { 2168 int wait; 2169 2170 /* wait until they're all suspended */ 2171 wait = pr->ps_singlecount > 0; 2172 while (wait) { 2173 sleep_setup(&pr->ps_singlecount, PWAIT, "suspend"); 2174 wait = pr->ps_singlecount > 0; 2175 sleep_finish(0, wait); 2176 if (!recheck) 2177 break; 2178 } 2179 2180 return wait; 2181 } 2182 2183 void 2184 single_thread_clear(struct proc *p, int flag) 2185 { 2186 struct process *pr = p->p_p; 2187 struct proc *q; 2188 int s; 2189 2190 KASSERT(pr->ps_single == p); 2191 KASSERT(curproc == p); 2192 2193 SCHED_LOCK(s); 2194 pr->ps_single = NULL; 2195 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2196 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2197 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2198 continue; 2199 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2200 2201 /* 2202 * if the thread was only stopped for single threading 2203 * then clearing that either makes it runnable or puts 2204 * it back into some sleep queue 2205 */ 2206 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2207 if (q->p_wchan == NULL) 2208 setrunnable(q); 2209 else { 2210 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2211 q->p_stat = SSLEEP; 2212 } 2213 } 2214 } 2215 SCHED_UNLOCK(s); 2216 } 2217 2218 void 2219 sigio_del(struct sigiolst *rmlist) 2220 { 2221 struct sigio *sigio; 2222 2223 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2224 LIST_REMOVE(sigio, sio_pgsigio); 2225 crfree(sigio->sio_ucred); 2226 free(sigio, M_SIGIO, sizeof(*sigio)); 2227 } 2228 } 2229 2230 void 2231 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2232 { 2233 struct sigio *sigio; 2234 2235 MUTEX_ASSERT_LOCKED(&sigio_lock); 2236 2237 sigio = sir->sir_sigio; 2238 if (sigio != NULL) { 2239 KASSERT(sigio->sio_myref == sir); 2240 sir->sir_sigio = NULL; 2241 2242 if (sigio->sio_pgid > 0) 2243 sigio->sio_proc = NULL; 2244 else 2245 sigio->sio_pgrp = NULL; 2246 LIST_REMOVE(sigio, sio_pgsigio); 2247 2248 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2249 } 2250 } 2251 2252 void 2253 sigio_free(struct sigio_ref *sir) 2254 { 2255 struct sigiolst rmlist; 2256 2257 if (sir->sir_sigio == NULL) 2258 return; 2259 2260 LIST_INIT(&rmlist); 2261 2262 mtx_enter(&sigio_lock); 2263 sigio_unlink(sir, &rmlist); 2264 mtx_leave(&sigio_lock); 2265 2266 sigio_del(&rmlist); 2267 } 2268 2269 void 2270 sigio_freelist(struct sigiolst *sigiolst) 2271 { 2272 struct sigiolst rmlist; 2273 struct sigio *sigio; 2274 2275 if (LIST_EMPTY(sigiolst)) 2276 return; 2277 2278 LIST_INIT(&rmlist); 2279 2280 mtx_enter(&sigio_lock); 2281 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2282 sigio_unlink(sigio->sio_myref, &rmlist); 2283 mtx_leave(&sigio_lock); 2284 2285 sigio_del(&rmlist); 2286 } 2287 2288 int 2289 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2290 { 2291 struct sigiolst rmlist; 2292 struct proc *p = curproc; 2293 struct pgrp *pgrp = NULL; 2294 struct process *pr = NULL; 2295 struct sigio *sigio; 2296 int error; 2297 pid_t pgid = *(int *)data; 2298 2299 if (pgid == 0) { 2300 sigio_free(sir); 2301 return (0); 2302 } 2303 2304 if (cmd == TIOCSPGRP) { 2305 if (pgid < 0) 2306 return (EINVAL); 2307 pgid = -pgid; 2308 } 2309 2310 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2311 sigio->sio_pgid = pgid; 2312 sigio->sio_ucred = crhold(p->p_ucred); 2313 sigio->sio_myref = sir; 2314 2315 LIST_INIT(&rmlist); 2316 2317 /* 2318 * The kernel lock, and not sleeping between prfind()/pgfind() and 2319 * linking of the sigio ensure that the process or process group does 2320 * not disappear unexpectedly. 2321 */ 2322 KERNEL_LOCK(); 2323 mtx_enter(&sigio_lock); 2324 2325 if (pgid > 0) { 2326 pr = prfind(pgid); 2327 if (pr == NULL) { 2328 error = ESRCH; 2329 goto fail; 2330 } 2331 2332 /* 2333 * Policy - Don't allow a process to FSETOWN a process 2334 * in another session. 2335 * 2336 * Remove this test to allow maximum flexibility or 2337 * restrict FSETOWN to the current process or process 2338 * group for maximum safety. 2339 */ 2340 if (pr->ps_session != p->p_p->ps_session) { 2341 error = EPERM; 2342 goto fail; 2343 } 2344 2345 if ((pr->ps_flags & PS_EXITING) != 0) { 2346 error = ESRCH; 2347 goto fail; 2348 } 2349 } else /* if (pgid < 0) */ { 2350 pgrp = pgfind(-pgid); 2351 if (pgrp == NULL) { 2352 error = ESRCH; 2353 goto fail; 2354 } 2355 2356 /* 2357 * Policy - Don't allow a process to FSETOWN a process 2358 * in another session. 2359 * 2360 * Remove this test to allow maximum flexibility or 2361 * restrict FSETOWN to the current process or process 2362 * group for maximum safety. 2363 */ 2364 if (pgrp->pg_session != p->p_p->ps_session) { 2365 error = EPERM; 2366 goto fail; 2367 } 2368 } 2369 2370 if (pgid > 0) { 2371 sigio->sio_proc = pr; 2372 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2373 } else { 2374 sigio->sio_pgrp = pgrp; 2375 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2376 } 2377 2378 sigio_unlink(sir, &rmlist); 2379 sir->sir_sigio = sigio; 2380 2381 mtx_leave(&sigio_lock); 2382 KERNEL_UNLOCK(); 2383 2384 sigio_del(&rmlist); 2385 2386 return (0); 2387 2388 fail: 2389 mtx_leave(&sigio_lock); 2390 KERNEL_UNLOCK(); 2391 2392 crfree(sigio->sio_ucred); 2393 free(sigio, M_SIGIO, sizeof(*sigio)); 2394 2395 return (error); 2396 } 2397 2398 void 2399 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2400 { 2401 struct sigio *sigio; 2402 pid_t pgid = 0; 2403 2404 mtx_enter(&sigio_lock); 2405 sigio = sir->sir_sigio; 2406 if (sigio != NULL) 2407 pgid = sigio->sio_pgid; 2408 mtx_leave(&sigio_lock); 2409 2410 if (cmd == TIOCGPGRP) 2411 pgid = -pgid; 2412 2413 *(int *)data = pgid; 2414 } 2415 2416 void 2417 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2418 { 2419 struct sigiolst rmlist; 2420 struct sigio *newsigio, *sigio; 2421 2422 sigio_free(dst); 2423 2424 if (src->sir_sigio == NULL) 2425 return; 2426 2427 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2428 LIST_INIT(&rmlist); 2429 2430 mtx_enter(&sigio_lock); 2431 2432 sigio = src->sir_sigio; 2433 if (sigio == NULL) { 2434 mtx_leave(&sigio_lock); 2435 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2436 return; 2437 } 2438 2439 newsigio->sio_pgid = sigio->sio_pgid; 2440 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2441 newsigio->sio_myref = dst; 2442 if (newsigio->sio_pgid > 0) { 2443 newsigio->sio_proc = sigio->sio_proc; 2444 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2445 sio_pgsigio); 2446 } else { 2447 newsigio->sio_pgrp = sigio->sio_pgrp; 2448 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2449 sio_pgsigio); 2450 } 2451 2452 sigio_unlink(dst, &rmlist); 2453 dst->sir_sigio = newsigio; 2454 2455 mtx_leave(&sigio_lock); 2456 2457 sigio_del(&rmlist); 2458 } 2459