1 /* $OpenBSD: kern_sig.c,v 1.327 2024/05/08 13:05:33 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 SET(p->p_sigmask, mask); 476 break; 477 case SIG_UNBLOCK: 478 CLR(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 p->p_sigmask = newmask; 508 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 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 SET(p->p_sigmask, catchmask); 774 if (reset != 0) { 775 sigset_t mask = sigmask(signum); 776 struct sigacts *ps = p->p_p->ps_sigacts; 777 778 mtx_enter(&p->p_p->ps_mtx); 779 ps->ps_sigcatch &= ~mask; 780 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 781 ps->ps_sigignore |= mask; 782 ps->ps_sigact[signum] = SIG_DFL; 783 mtx_leave(&p->p_p->ps_mtx); 784 } 785 } 786 787 /* 788 * Send a signal caused by a trap to the current thread 789 * If it will be caught immediately, deliver it with correct code. 790 * Otherwise, post it normally. 791 */ 792 void 793 trapsignal(struct proc *p, int signum, u_long trapno, int code, 794 union sigval sigval) 795 { 796 struct process *pr = p->p_p; 797 struct sigctx ctx; 798 int mask; 799 800 switch (signum) { 801 case SIGILL: 802 if (code == ILL_BTCFI) { 803 pr->ps_acflag |= ABTCFI; 804 break; 805 } 806 /* FALLTHROUGH */ 807 case SIGBUS: 808 case SIGSEGV: 809 pr->ps_acflag |= ATRAP; 810 break; 811 } 812 813 mask = sigmask(signum); 814 setsigctx(p, signum, &ctx); 815 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 816 (p->p_sigmask & mask) == 0) { 817 siginfo_t si; 818 819 initsiginfo(&si, signum, trapno, code, sigval); 820 #ifdef KTRACE 821 if (KTRPOINT(p, KTR_PSIG)) { 822 ktrpsig(p, signum, ctx.sig_action, 823 p->p_sigmask, code, &si); 824 } 825 #endif 826 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 827 ctx.sig_info, ctx.sig_onstack)) { 828 KERNEL_LOCK(); 829 sigexit(p, SIGILL); 830 /* NOTREACHED */ 831 } 832 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 833 } else { 834 p->p_sisig = signum; 835 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 836 p->p_sicode = code; 837 p->p_sigval = sigval; 838 839 /* 840 * If traced, stop if signal is masked, and stay stopped 841 * until released by the debugger. If our parent process 842 * is waiting for us, don't hang as we could deadlock. 843 */ 844 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 845 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 846 int s; 847 848 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 849 pr->ps_xsig = signum; 850 851 SCHED_LOCK(s); 852 proc_stop(p, 1); 853 SCHED_UNLOCK(s); 854 855 signum = pr->ps_xsig; 856 single_thread_clear(p, 0); 857 858 /* 859 * If we are no longer being traced, or the parent 860 * didn't give us a signal, skip sending the signal. 861 */ 862 if ((pr->ps_flags & PS_TRACED) == 0 || 863 signum == 0) 864 return; 865 866 /* update signal info */ 867 p->p_sisig = signum; 868 mask = sigmask(signum); 869 } 870 871 /* 872 * Signals like SIGBUS and SIGSEGV should not, when 873 * generated by the kernel, be ignorable or blockable. 874 * If it is and we're not being traced, then just kill 875 * the process. 876 * After vfs_shutdown(9), init(8) cannot receive signals 877 * because new code pages of the signal handler cannot be 878 * mapped from halted storage. init(8) may not die or the 879 * kernel panics. Better loop between signal handler and 880 * page fault trap until the machine is halted. 881 */ 882 if ((pr->ps_flags & PS_TRACED) == 0 && 883 (sigprop[signum] & SA_KILL) && 884 ((p->p_sigmask & mask) || ctx.sig_ignore) && 885 pr->ps_pid != 1) { 886 KERNEL_LOCK(); 887 sigexit(p, signum); 888 /* NOTREACHED */ 889 } 890 KERNEL_LOCK(); 891 ptsignal(p, signum, STHREAD); 892 KERNEL_UNLOCK(); 893 } 894 } 895 896 /* 897 * Send the signal to the process. If the signal has an action, the action 898 * is usually performed by the target process rather than the caller; we add 899 * the signal to the set of pending signals for the process. 900 * 901 * Exceptions: 902 * o When a stop signal is sent to a sleeping process that takes the 903 * default action, the process is stopped without awakening it. 904 * o SIGCONT restarts stopped processes (or puts them back to sleep) 905 * regardless of the signal action (eg, blocked or ignored). 906 * 907 * Other ignored signals are discarded immediately. 908 */ 909 void 910 psignal(struct proc *p, int signum) 911 { 912 ptsignal(p, signum, SPROCESS); 913 } 914 915 /* 916 * type = SPROCESS process signal, can be diverted (sigwait()) 917 * type = STHREAD thread signal, but should be propagated if unhandled 918 * type = SPROPAGATED propagated to this thread, so don't propagate again 919 */ 920 void 921 ptsignal(struct proc *p, int signum, enum signal_type type) 922 { 923 int s, prop; 924 sig_t action, altaction = SIG_DFL; 925 sigset_t mask, sigmask; 926 int *siglist; 927 struct process *pr = p->p_p; 928 struct proc *q; 929 int wakeparent = 0; 930 931 KERNEL_ASSERT_LOCKED(); 932 933 #ifdef DIAGNOSTIC 934 if ((u_int)signum >= NSIG || signum == 0) 935 panic("psignal signal number"); 936 #endif 937 938 /* Ignore signal if the target process is exiting */ 939 if (pr->ps_flags & PS_EXITING) 940 return; 941 942 mask = sigmask(signum); 943 sigmask = READ_ONCE(p->p_sigmask); 944 945 if (type == SPROCESS) { 946 sigset_t tmpmask; 947 948 /* Accept SIGKILL to coredumping processes */ 949 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 950 atomic_setbits_int(&pr->ps_siglist, mask); 951 return; 952 } 953 954 /* 955 * If the current thread can process the signal 956 * immediately (it's unblocked) then have it take it. 957 */ 958 q = curproc; 959 tmpmask = READ_ONCE(q->p_sigmask); 960 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 961 (tmpmask & mask) == 0) { 962 p = q; 963 sigmask = tmpmask; 964 } else { 965 /* 966 * A process-wide signal can be diverted to a 967 * different thread that's in sigwait() for this 968 * signal. If there isn't such a thread, then 969 * pick a thread that doesn't have it blocked so 970 * that the stop/kill consideration isn't 971 * delayed. Otherwise, mark it pending on the 972 * main thread. 973 */ 974 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 975 976 /* ignore exiting threads */ 977 if (q->p_flag & P_WEXIT) 978 continue; 979 980 /* skip threads that have the signal blocked */ 981 tmpmask = READ_ONCE(q->p_sigmask); 982 if ((tmpmask & mask) != 0) 983 continue; 984 985 /* okay, could send to this thread */ 986 p = q; 987 sigmask = tmpmask; 988 989 /* 990 * sigsuspend, sigwait, ppoll/pselect, etc? 991 * Definitely go to this thread, as it's 992 * already blocked in the kernel. 993 */ 994 if (q->p_flag & P_SIGSUSPEND) 995 break; 996 } 997 } 998 } 999 1000 if (type != SPROPAGATED) 1001 knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); 1002 1003 prop = sigprop[signum]; 1004 1005 /* 1006 * If proc is traced, always give parent a chance. 1007 */ 1008 if (pr->ps_flags & PS_TRACED) { 1009 action = SIG_DFL; 1010 } else { 1011 sigset_t sigcatch, sigignore; 1012 1013 /* 1014 * If the signal is being ignored, 1015 * then we forget about it immediately. 1016 * (Note: we don't set SIGCONT in ps_sigignore, 1017 * and if it is set to SIG_IGN, 1018 * action will be SIG_DFL here.) 1019 */ 1020 mtx_enter(&pr->ps_mtx); 1021 sigignore = pr->ps_sigacts->ps_sigignore; 1022 sigcatch = pr->ps_sigacts->ps_sigcatch; 1023 mtx_leave(&pr->ps_mtx); 1024 1025 if (sigignore & mask) 1026 return; 1027 if (sigmask & mask) { 1028 action = SIG_HOLD; 1029 if (sigcatch & mask) 1030 altaction = SIG_CATCH; 1031 } else if (sigcatch & mask) { 1032 action = SIG_CATCH; 1033 } else { 1034 action = SIG_DFL; 1035 1036 if (prop & SA_KILL && pr->ps_nice > NZERO) 1037 pr->ps_nice = NZERO; 1038 1039 /* 1040 * If sending a tty stop signal to a member of an 1041 * orphaned process group, discard the signal here if 1042 * the action is default; don't stop the process below 1043 * if sleeping, and don't clear any pending SIGCONT. 1044 */ 1045 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1046 return; 1047 } 1048 } 1049 /* 1050 * If delivered to process, mark as pending there. Continue and stop 1051 * signals will be propagated to all threads. So they are always 1052 * marked at thread level. 1053 */ 1054 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1055 if (prop & (SA_CONT | SA_STOP)) 1056 siglist = &p->p_siglist; 1057 1058 /* 1059 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1060 */ 1061 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1062 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1063 if (q != p) 1064 ptsignal(q, signum, SPROPAGATED); 1065 1066 SCHED_LOCK(s); 1067 1068 switch (p->p_stat) { 1069 1070 case SSLEEP: 1071 /* 1072 * If process is sleeping uninterruptibly 1073 * we can't interrupt the sleep... the signal will 1074 * be noticed when the process returns through 1075 * trap() or syscall(). 1076 */ 1077 if ((p->p_flag & P_SINTR) == 0) 1078 goto out; 1079 /* 1080 * Process is sleeping and traced... make it runnable 1081 * so it can discover the signal in cursig() and stop 1082 * for the parent. 1083 */ 1084 if (pr->ps_flags & PS_TRACED) 1085 goto run; 1086 1087 /* 1088 * Recheck sigmask before waking up the process, 1089 * there is a chance that while sending the signal 1090 * the process changed sigmask and went to sleep. 1091 */ 1092 sigmask = READ_ONCE(p->p_sigmask); 1093 if (sigmask & mask) 1094 goto out; 1095 else if (action == SIG_HOLD) { 1096 /* signal got unmasked, get proper action */ 1097 action = altaction; 1098 1099 if (action == SIG_DFL) { 1100 if (prop & SA_KILL && pr->ps_nice > NZERO) 1101 pr->ps_nice = NZERO; 1102 1103 /* 1104 * Discard tty stop signals sent to an 1105 * orphaned process group, see above. 1106 */ 1107 if (prop & SA_TTYSTOP && 1108 pr->ps_pgrp->pg_jobc == 0) { 1109 SCHED_UNLOCK(s); 1110 return; 1111 } 1112 } 1113 } 1114 1115 /* 1116 * If SIGCONT is default (or ignored) and process is 1117 * asleep, we are finished; the process should not 1118 * be awakened. 1119 */ 1120 if ((prop & SA_CONT) && action == SIG_DFL) { 1121 mask = 0; 1122 goto out; 1123 } 1124 /* 1125 * When a sleeping process receives a stop 1126 * signal, process immediately if possible. 1127 */ 1128 if ((prop & SA_STOP) && action == SIG_DFL) { 1129 /* 1130 * If a child holding parent blocked, 1131 * stopping could cause deadlock. 1132 */ 1133 if (pr->ps_flags & PS_PPWAIT) 1134 goto out; 1135 mask = 0; 1136 pr->ps_xsig = signum; 1137 proc_stop(p, 0); 1138 goto out; 1139 } 1140 /* 1141 * All other (caught or default) signals 1142 * cause the process to run. 1143 */ 1144 goto runfast; 1145 /* NOTREACHED */ 1146 1147 case SSTOP: 1148 /* 1149 * If traced process is already stopped, 1150 * then no further action is necessary. 1151 */ 1152 if (pr->ps_flags & PS_TRACED) 1153 goto out; 1154 1155 /* 1156 * Kill signal always sets processes running. 1157 */ 1158 if (signum == SIGKILL) { 1159 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1160 goto runfast; 1161 } 1162 1163 if (prop & SA_CONT) { 1164 /* 1165 * If SIGCONT is default (or ignored), we continue the 1166 * process but don't leave the signal in p_siglist, as 1167 * it has no further action. If SIGCONT is held, we 1168 * continue the process and leave the signal in 1169 * p_siglist. If the process catches SIGCONT, let it 1170 * handle the signal itself. If it isn't waiting on 1171 * an event, then it goes back to run state. 1172 * Otherwise, process goes back to sleep state. 1173 */ 1174 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1175 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1176 wakeparent = 1; 1177 if (action == SIG_DFL) 1178 mask = 0; 1179 if (action == SIG_CATCH) 1180 goto runfast; 1181 if (p->p_wchan == NULL) 1182 goto run; 1183 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1184 p->p_stat = SSLEEP; 1185 goto out; 1186 } 1187 1188 /* 1189 * Defer further processing for signals which are held, 1190 * except that stopped processes must be continued by SIGCONT. 1191 */ 1192 if (action == SIG_HOLD) 1193 goto out; 1194 1195 if (prop & SA_STOP) { 1196 /* 1197 * Already stopped, don't need to stop again. 1198 * (If we did the shell could get confused.) 1199 */ 1200 mask = 0; 1201 goto out; 1202 } 1203 1204 /* 1205 * If process is sleeping interruptibly, then simulate a 1206 * wakeup so that when it is continued, it will be made 1207 * runnable and can look at the signal. But don't make 1208 * the process runnable, leave it stopped. 1209 */ 1210 if (p->p_flag & P_SINTR) 1211 unsleep(p); 1212 goto out; 1213 1214 case SONPROC: 1215 if (action == SIG_HOLD) 1216 goto out; 1217 1218 /* set siglist before issuing the ast */ 1219 atomic_setbits_int(siglist, mask); 1220 mask = 0; 1221 signotify(p); 1222 /* FALLTHROUGH */ 1223 default: 1224 /* 1225 * SRUN, SIDL, SDEAD do nothing with the signal, 1226 * other than kicking ourselves if we are running. 1227 * It will either never be noticed, or noticed very soon. 1228 */ 1229 goto out; 1230 } 1231 /* NOTREACHED */ 1232 1233 runfast: 1234 /* 1235 * Raise priority to at least PUSER. 1236 */ 1237 if (p->p_usrpri > PUSER) 1238 p->p_usrpri = PUSER; 1239 run: 1240 unsleep(p); 1241 setrunnable(p); 1242 out: 1243 /* finally adjust siglist */ 1244 if (mask) 1245 atomic_setbits_int(siglist, mask); 1246 if (prop & SA_CONT) { 1247 atomic_clearbits_int(siglist, STOPSIGMASK); 1248 } 1249 if (prop & SA_STOP) { 1250 atomic_clearbits_int(siglist, CONTSIGMASK); 1251 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1252 } 1253 1254 SCHED_UNLOCK(s); 1255 if (wakeparent) 1256 wakeup(pr->ps_pptr); 1257 } 1258 1259 /* fill the signal context which should be used by postsig() and issignal() */ 1260 void 1261 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1262 { 1263 struct sigacts *ps = p->p_p->ps_sigacts; 1264 sigset_t mask; 1265 1266 mtx_enter(&p->p_p->ps_mtx); 1267 mask = sigmask(signum); 1268 sctx->sig_action = ps->ps_sigact[signum]; 1269 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1270 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1271 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1272 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1273 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1274 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1275 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1276 mtx_leave(&p->p_p->ps_mtx); 1277 } 1278 1279 /* 1280 * Determine signal that should be delivered to process p, the current 1281 * process, 0 if none. 1282 * 1283 * If the current process has received a signal (should be caught or cause 1284 * termination, should interrupt current syscall), return the signal number. 1285 * Stop signals with default action are processed immediately, then cleared; 1286 * they aren't returned. This is checked after each entry to the system for 1287 * a syscall or trap. The normal call sequence is 1288 * 1289 * while (signum = cursig(curproc, &ctx)) 1290 * postsig(signum, &ctx); 1291 * 1292 * Assumes that if the P_SINTR flag is set, we're holding both the 1293 * kernel and scheduler locks. 1294 */ 1295 int 1296 cursig(struct proc *p, struct sigctx *sctx) 1297 { 1298 struct process *pr = p->p_p; 1299 int signum, mask, prop; 1300 sigset_t ps_siglist; 1301 int s; 1302 1303 KASSERT(p == curproc); 1304 1305 for (;;) { 1306 ps_siglist = READ_ONCE(pr->ps_siglist); 1307 membar_consumer(); 1308 mask = SIGPENDING(p); 1309 if (pr->ps_flags & PS_PPWAIT) 1310 mask &= ~STOPSIGMASK; 1311 if (mask == 0) /* no signal to send */ 1312 return (0); 1313 signum = ffs((long)mask); 1314 mask = sigmask(signum); 1315 1316 /* take the signal! */ 1317 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1318 ps_siglist & ~mask) != ps_siglist) { 1319 /* lost race taking the process signal, restart */ 1320 continue; 1321 } 1322 atomic_clearbits_int(&p->p_siglist, mask); 1323 setsigctx(p, signum, sctx); 1324 1325 /* 1326 * We should see pending but ignored signals 1327 * only if PS_TRACED was on when they were posted. 1328 */ 1329 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1330 continue; 1331 1332 /* 1333 * If traced, always stop, and stay stopped until released 1334 * by the debugger. If our parent process is waiting for 1335 * us, don't hang as we could deadlock. 1336 */ 1337 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1338 signum != SIGKILL) { 1339 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1340 pr->ps_xsig = signum; 1341 1342 SCHED_LOCK(s); 1343 proc_stop(p, 1); 1344 SCHED_UNLOCK(s); 1345 1346 /* 1347 * re-take the signal before releasing 1348 * the other threads. Must check the continue 1349 * conditions below and only take the signal if 1350 * those are not true. 1351 */ 1352 signum = pr->ps_xsig; 1353 mask = sigmask(signum); 1354 setsigctx(p, signum, sctx); 1355 if (!((pr->ps_flags & PS_TRACED) == 0 || 1356 signum == 0 || 1357 (p->p_sigmask & mask) != 0)) { 1358 atomic_clearbits_int(&p->p_siglist, mask); 1359 atomic_clearbits_int(&pr->ps_siglist, mask); 1360 } 1361 1362 single_thread_clear(p, 0); 1363 1364 /* 1365 * If we are no longer being traced, or the parent 1366 * didn't give us a signal, look for more signals. 1367 */ 1368 if ((pr->ps_flags & PS_TRACED) == 0 || 1369 signum == 0) 1370 continue; 1371 1372 /* 1373 * If the new signal is being masked, look for other 1374 * signals. 1375 */ 1376 if ((p->p_sigmask & mask) != 0) 1377 continue; 1378 1379 } 1380 1381 prop = sigprop[signum]; 1382 1383 /* 1384 * Decide whether the signal should be returned. 1385 * Return the signal's number, or fall through 1386 * to clear it from the pending mask. 1387 */ 1388 switch ((long)sctx->sig_action) { 1389 case (long)SIG_DFL: 1390 /* 1391 * Don't take default actions on system processes. 1392 */ 1393 if (pr->ps_pid <= 1) { 1394 #ifdef DIAGNOSTIC 1395 /* 1396 * Are you sure you want to ignore SIGSEGV 1397 * in init? XXX 1398 */ 1399 printf("Process (pid %d) got signal" 1400 " %d\n", pr->ps_pid, signum); 1401 #endif 1402 break; /* == ignore */ 1403 } 1404 /* 1405 * If there is a pending stop signal to process 1406 * with default action, stop here, 1407 * then clear the signal. However, 1408 * if process is member of an orphaned 1409 * process group, ignore tty stop signals. 1410 */ 1411 if (prop & SA_STOP) { 1412 if (pr->ps_flags & PS_TRACED || 1413 (pr->ps_pgrp->pg_jobc == 0 && 1414 prop & SA_TTYSTOP)) 1415 break; /* == ignore */ 1416 pr->ps_xsig = signum; 1417 SCHED_LOCK(s); 1418 proc_stop(p, 1); 1419 SCHED_UNLOCK(s); 1420 break; 1421 } else if (prop & SA_IGNORE) { 1422 /* 1423 * Except for SIGCONT, shouldn't get here. 1424 * Default action is to ignore; drop it. 1425 */ 1426 break; /* == ignore */ 1427 } else 1428 goto keep; 1429 /* NOTREACHED */ 1430 case (long)SIG_IGN: 1431 /* 1432 * Masking above should prevent us ever trying 1433 * to take action on an ignored signal other 1434 * than SIGCONT, unless process is traced. 1435 */ 1436 if ((prop & SA_CONT) == 0 && 1437 (pr->ps_flags & PS_TRACED) == 0) 1438 printf("%s\n", __func__); 1439 break; /* == ignore */ 1440 default: 1441 /* 1442 * This signal has an action, let 1443 * postsig() process it. 1444 */ 1445 goto keep; 1446 } 1447 } 1448 /* NOTREACHED */ 1449 1450 keep: 1451 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1452 return (signum); 1453 } 1454 1455 /* 1456 * Put the argument process into the stopped state and notify the parent 1457 * via wakeup. Signals are handled elsewhere. The process must not be 1458 * on the run queue. 1459 */ 1460 void 1461 proc_stop(struct proc *p, int sw) 1462 { 1463 struct process *pr = p->p_p; 1464 1465 #ifdef MULTIPROCESSOR 1466 SCHED_ASSERT_LOCKED(); 1467 #endif 1468 /* do not stop exiting procs */ 1469 if (ISSET(p->p_flag, P_WEXIT)) 1470 return; 1471 1472 p->p_stat = SSTOP; 1473 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1474 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1475 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1476 /* 1477 * We need this soft interrupt to be handled fast. 1478 * Extra calls to softclock don't hurt. 1479 */ 1480 softintr_schedule(proc_stop_si); 1481 if (sw) 1482 mi_switch(); 1483 } 1484 1485 /* 1486 * Called from a soft interrupt to send signals to the parents of stopped 1487 * processes. 1488 * We can't do this in proc_stop because it's called with nasty locks held 1489 * and we would need recursive scheduler lock to deal with that. 1490 */ 1491 void 1492 proc_stop_sweep(void *v) 1493 { 1494 struct process *pr; 1495 1496 LIST_FOREACH(pr, &allprocess, ps_list) { 1497 if ((pr->ps_flags & PS_STOPPED) == 0) 1498 continue; 1499 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1500 1501 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1502 prsignal(pr->ps_pptr, SIGCHLD); 1503 wakeup(pr->ps_pptr); 1504 } 1505 } 1506 1507 /* 1508 * Take the action for the specified signal 1509 * from the current set of pending signals. 1510 */ 1511 void 1512 postsig(struct proc *p, int signum, struct sigctx *sctx) 1513 { 1514 u_long trapno; 1515 int mask, returnmask; 1516 siginfo_t si; 1517 union sigval sigval; 1518 int code; 1519 1520 KASSERT(signum != 0); 1521 1522 mask = sigmask(signum); 1523 atomic_clearbits_int(&p->p_siglist, mask); 1524 sigval.sival_ptr = NULL; 1525 1526 if (p->p_sisig != signum) { 1527 trapno = 0; 1528 code = SI_USER; 1529 sigval.sival_ptr = NULL; 1530 } else { 1531 trapno = p->p_sitrapno; 1532 code = p->p_sicode; 1533 sigval = p->p_sigval; 1534 } 1535 initsiginfo(&si, signum, trapno, code, sigval); 1536 1537 #ifdef KTRACE 1538 if (KTRPOINT(p, KTR_PSIG)) { 1539 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1540 p->p_oldmask : p->p_sigmask, code, &si); 1541 } 1542 #endif 1543 if (sctx->sig_action == SIG_DFL) { 1544 /* 1545 * Default action, where the default is to kill 1546 * the process. (Other cases were ignored above.) 1547 */ 1548 KERNEL_LOCK(); 1549 sigexit(p, signum); 1550 /* NOTREACHED */ 1551 } else { 1552 /* 1553 * If we get here, the signal must be caught. 1554 */ 1555 #ifdef DIAGNOSTIC 1556 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1557 panic("postsig action"); 1558 #endif 1559 /* 1560 * Set the new mask value and also defer further 1561 * occurrences of this signal. 1562 * 1563 * Special case: user has done a sigpause. Here the 1564 * current mask is not of interest, but rather the 1565 * mask from before the sigpause is what we want 1566 * restored after the signal processing is completed. 1567 */ 1568 if (p->p_flag & P_SIGSUSPEND) { 1569 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1570 returnmask = p->p_oldmask; 1571 } else { 1572 returnmask = p->p_sigmask; 1573 } 1574 if (p->p_sisig == signum) { 1575 p->p_sisig = 0; 1576 p->p_sitrapno = 0; 1577 p->p_sicode = SI_USER; 1578 p->p_sigval.sival_ptr = NULL; 1579 } 1580 1581 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1582 sctx->sig_info, sctx->sig_onstack)) { 1583 KERNEL_LOCK(); 1584 sigexit(p, SIGILL); 1585 /* NOTREACHED */ 1586 } 1587 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1588 } 1589 } 1590 1591 /* 1592 * Force the current process to exit with the specified signal, dumping core 1593 * if appropriate. We bypass the normal tests for masked and caught signals, 1594 * allowing unrecoverable failures to terminate the process without changing 1595 * signal state. Mark the accounting record with the signal termination. 1596 * If dumping core, save the signal number for the debugger. Calls exit and 1597 * does not return. 1598 */ 1599 void 1600 sigexit(struct proc *p, int signum) 1601 { 1602 /* Mark process as going away */ 1603 atomic_setbits_int(&p->p_flag, P_WEXIT); 1604 1605 p->p_p->ps_acflag |= AXSIG; 1606 if (sigprop[signum] & SA_CORE) { 1607 p->p_sisig = signum; 1608 1609 /* if there are other threads, pause them */ 1610 if (P_HASSIBLING(p)) 1611 single_thread_set(p, SINGLE_UNWIND); 1612 1613 if (coredump(p) == 0) 1614 signum |= WCOREFLAG; 1615 } 1616 exit1(p, 0, signum, EXIT_NORMAL); 1617 /* NOTREACHED */ 1618 } 1619 1620 /* 1621 * Send uncatchable SIGABRT for coredump. 1622 */ 1623 void 1624 sigabort(struct proc *p) 1625 { 1626 struct sigaction sa; 1627 1628 KASSERT(p == curproc || panicstr || db_active); 1629 1630 memset(&sa, 0, sizeof sa); 1631 sa.sa_handler = SIG_DFL; 1632 setsigvec(p, SIGABRT, &sa); 1633 CLR(p->p_sigmask, sigmask(SIGABRT)); 1634 psignal(p, SIGABRT); 1635 } 1636 1637 /* 1638 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1639 * thread, and 0 otherwise. 1640 */ 1641 int 1642 sigismasked(struct proc *p, int sig) 1643 { 1644 struct process *pr = p->p_p; 1645 int rv; 1646 1647 KASSERT(p == curproc); 1648 1649 mtx_enter(&pr->ps_mtx); 1650 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1651 (p->p_sigmask & sigmask(sig)); 1652 mtx_leave(&pr->ps_mtx); 1653 1654 return !!rv; 1655 } 1656 1657 struct coredump_iostate { 1658 struct proc *io_proc; 1659 struct vnode *io_vp; 1660 struct ucred *io_cred; 1661 off_t io_offset; 1662 }; 1663 1664 /* 1665 * Dump core, into a file named "progname.core", unless the process was 1666 * setuid/setgid. 1667 */ 1668 int 1669 coredump(struct proc *p) 1670 { 1671 #ifdef SMALL_KERNEL 1672 return EPERM; 1673 #else 1674 struct process *pr = p->p_p; 1675 struct vnode *vp; 1676 struct ucred *cred = p->p_ucred; 1677 struct vmspace *vm = p->p_vmspace; 1678 struct nameidata nd; 1679 struct vattr vattr; 1680 struct coredump_iostate io; 1681 int error, len, incrash = 0; 1682 char *name; 1683 const char *dir = "/var/crash"; 1684 1685 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1686 1687 #ifdef PMAP_CHECK_COPYIN 1688 /* disable copyin checks, so we can write out text sections if needed */ 1689 p->p_vmspace->vm_map.check_copyin_count = 0; 1690 #endif 1691 1692 /* Don't dump if will exceed file size limit. */ 1693 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1694 return (EFBIG); 1695 1696 name = pool_get(&namei_pool, PR_WAITOK); 1697 1698 /* 1699 * If the process has inconsistent uids, nosuidcoredump 1700 * determines coredump placement policy. 1701 */ 1702 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1703 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1704 if (nosuidcoredump == 3) { 1705 /* 1706 * If the program directory does not exist, dumps of 1707 * that core will silently fail. 1708 */ 1709 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1710 dir, pr->ps_comm, pr->ps_pid); 1711 incrash = KERNELPATH; 1712 } else if (nosuidcoredump == 2) { 1713 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1714 dir, pr->ps_comm); 1715 incrash = KERNELPATH; 1716 } else { 1717 pool_put(&namei_pool, name); 1718 return (EPERM); 1719 } 1720 } else 1721 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1722 1723 if (len >= MAXPATHLEN) { 1724 pool_put(&namei_pool, name); 1725 return (EACCES); 1726 } 1727 1728 /* 1729 * Control the UID used to write out. The normal case uses 1730 * the real UID. If the sugid case is going to write into the 1731 * controlled directory, we do so as root. 1732 */ 1733 if (incrash == 0) { 1734 cred = crdup(cred); 1735 cred->cr_uid = cred->cr_ruid; 1736 cred->cr_gid = cred->cr_rgid; 1737 } else { 1738 if (p->p_fd->fd_rdir) { 1739 vrele(p->p_fd->fd_rdir); 1740 p->p_fd->fd_rdir = NULL; 1741 } 1742 p->p_ucred = crdup(p->p_ucred); 1743 crfree(cred); 1744 cred = p->p_ucred; 1745 crhold(cred); 1746 cred->cr_uid = 0; 1747 cred->cr_gid = 0; 1748 } 1749 1750 /* incrash should be 0 or KERNELPATH only */ 1751 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1752 1753 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1754 S_IRUSR | S_IWUSR); 1755 1756 if (error) 1757 goto out; 1758 1759 /* 1760 * Don't dump to non-regular files, files with links, or files 1761 * owned by someone else. 1762 */ 1763 vp = nd.ni_vp; 1764 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1765 VOP_UNLOCK(vp); 1766 vn_close(vp, FWRITE, cred, p); 1767 goto out; 1768 } 1769 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1770 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1771 vattr.va_uid != cred->cr_uid) { 1772 error = EACCES; 1773 VOP_UNLOCK(vp); 1774 vn_close(vp, FWRITE, cred, p); 1775 goto out; 1776 } 1777 VATTR_NULL(&vattr); 1778 vattr.va_size = 0; 1779 VOP_SETATTR(vp, &vattr, cred, p); 1780 pr->ps_acflag |= ACORE; 1781 1782 io.io_proc = p; 1783 io.io_vp = vp; 1784 io.io_cred = cred; 1785 io.io_offset = 0; 1786 VOP_UNLOCK(vp); 1787 vref(vp); 1788 error = vn_close(vp, FWRITE, cred, p); 1789 if (error == 0) 1790 error = coredump_elf(p, &io); 1791 vrele(vp); 1792 out: 1793 crfree(cred); 1794 pool_put(&namei_pool, name); 1795 return (error); 1796 #endif 1797 } 1798 1799 #ifndef SMALL_KERNEL 1800 int 1801 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1802 int isvnode) 1803 { 1804 struct coredump_iostate *io = cookie; 1805 off_t coffset = 0; 1806 size_t csize; 1807 int chunk, error; 1808 1809 csize = len; 1810 do { 1811 if (sigmask(SIGKILL) & 1812 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1813 return (EINTR); 1814 1815 /* Rest of the loop sleeps with lock held, so... */ 1816 yield(); 1817 1818 chunk = MIN(csize, MAXPHYS); 1819 error = vn_rdwr(UIO_WRITE, io->io_vp, 1820 (caddr_t)data + coffset, chunk, 1821 io->io_offset + coffset, segflg, 1822 IO_UNIT, io->io_cred, NULL, io->io_proc); 1823 if (error && (error != EFAULT || !isvnode)) { 1824 struct process *pr = io->io_proc->p_p; 1825 1826 if (error == ENOSPC) 1827 log(LOG_ERR, 1828 "coredump of %s(%d) failed, filesystem full\n", 1829 pr->ps_comm, pr->ps_pid); 1830 else 1831 log(LOG_ERR, 1832 "coredump of %s(%d), write failed: errno %d\n", 1833 pr->ps_comm, pr->ps_pid, error); 1834 return (error); 1835 } 1836 1837 coffset += chunk; 1838 csize -= chunk; 1839 } while (csize > 0); 1840 1841 io->io_offset += len; 1842 return (0); 1843 } 1844 1845 void 1846 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1847 { 1848 struct coredump_iostate *io = cookie; 1849 1850 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1851 } 1852 1853 #endif /* !SMALL_KERNEL */ 1854 1855 /* 1856 * Nonexistent system call-- signal process (may want to handle it). 1857 * Flag error in case process won't see signal immediately (blocked or ignored). 1858 */ 1859 int 1860 sys_nosys(struct proc *p, void *v, register_t *retval) 1861 { 1862 ptsignal(p, SIGSYS, STHREAD); 1863 return (ENOSYS); 1864 } 1865 1866 int 1867 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1868 { 1869 struct sys___thrsigdivert_args /* { 1870 syscallarg(sigset_t) sigmask; 1871 syscallarg(siginfo_t *) info; 1872 syscallarg(const struct timespec *) timeout; 1873 } */ *uap = v; 1874 struct sigctx ctx; 1875 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1876 siginfo_t si; 1877 uint64_t nsecs = INFSLP; 1878 int timeinvalid = 0; 1879 int error = 0; 1880 1881 memset(&si, 0, sizeof(si)); 1882 1883 if (SCARG(uap, timeout) != NULL) { 1884 struct timespec ts; 1885 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1886 return (error); 1887 #ifdef KTRACE 1888 if (KTRPOINT(p, KTR_STRUCT)) 1889 ktrreltimespec(p, &ts); 1890 #endif 1891 if (!timespecisvalid(&ts)) 1892 timeinvalid = 1; 1893 else 1894 nsecs = TIMESPEC_TO_NSEC(&ts); 1895 } 1896 1897 dosigsuspend(p, p->p_sigmask &~ mask); 1898 for (;;) { 1899 si.si_signo = cursig(p, &ctx); 1900 if (si.si_signo != 0) { 1901 sigset_t smask = sigmask(si.si_signo); 1902 if (smask & mask) { 1903 atomic_clearbits_int(&p->p_siglist, smask); 1904 error = 0; 1905 break; 1906 } 1907 } 1908 1909 /* per-POSIX, delay this error until after the above */ 1910 if (timeinvalid) 1911 error = EINVAL; 1912 /* per-POSIX, return immediately if timeout is zero-valued */ 1913 if (nsecs == 0) 1914 error = EAGAIN; 1915 1916 if (error != 0) 1917 break; 1918 1919 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1920 } 1921 1922 if (error == 0) { 1923 *retval = si.si_signo; 1924 if (SCARG(uap, info) != NULL) { 1925 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1926 #ifdef KTRACE 1927 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1928 ktrsiginfo(p, &si); 1929 #endif 1930 } 1931 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1932 /* 1933 * Restarting is wrong if there's a timeout, as it'll be 1934 * for the same interval again 1935 */ 1936 error = EINTR; 1937 } 1938 1939 return (error); 1940 } 1941 1942 void 1943 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1944 { 1945 memset(si, 0, sizeof(*si)); 1946 1947 si->si_signo = sig; 1948 si->si_code = code; 1949 if (code == SI_USER) { 1950 si->si_value = val; 1951 } else { 1952 switch (sig) { 1953 case SIGSEGV: 1954 case SIGILL: 1955 case SIGBUS: 1956 case SIGFPE: 1957 si->si_addr = val.sival_ptr; 1958 si->si_trapno = trapno; 1959 break; 1960 case SIGXFSZ: 1961 break; 1962 } 1963 } 1964 } 1965 1966 int 1967 filt_sigattach(struct knote *kn) 1968 { 1969 struct process *pr = curproc->p_p; 1970 int s; 1971 1972 if (kn->kn_id >= NSIG) 1973 return EINVAL; 1974 1975 kn->kn_ptr.p_process = pr; 1976 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1977 1978 s = splhigh(); 1979 klist_insert_locked(&pr->ps_klist, kn); 1980 splx(s); 1981 1982 return (0); 1983 } 1984 1985 void 1986 filt_sigdetach(struct knote *kn) 1987 { 1988 struct process *pr = kn->kn_ptr.p_process; 1989 int s; 1990 1991 s = splhigh(); 1992 klist_remove_locked(&pr->ps_klist, kn); 1993 splx(s); 1994 } 1995 1996 /* 1997 * signal knotes are shared with proc knotes, so we apply a mask to 1998 * the hint in order to differentiate them from process hints. This 1999 * could be avoided by using a signal-specific knote list, but probably 2000 * isn't worth the trouble. 2001 */ 2002 int 2003 filt_signal(struct knote *kn, long hint) 2004 { 2005 2006 if (hint & NOTE_SIGNAL) { 2007 hint &= ~NOTE_SIGNAL; 2008 2009 if (kn->kn_id == hint) 2010 kn->kn_data++; 2011 } 2012 return (kn->kn_data != 0); 2013 } 2014 2015 void 2016 userret(struct proc *p) 2017 { 2018 struct sigctx ctx; 2019 int signum; 2020 2021 if (p->p_flag & P_SUSPSINGLE) 2022 single_thread_check(p, 0); 2023 2024 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 2025 if (p->p_flag & P_PROFPEND) { 2026 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 2027 KERNEL_LOCK(); 2028 psignal(p, SIGPROF); 2029 KERNEL_UNLOCK(); 2030 } 2031 if (p->p_flag & P_ALRMPEND) { 2032 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 2033 KERNEL_LOCK(); 2034 psignal(p, SIGVTALRM); 2035 KERNEL_UNLOCK(); 2036 } 2037 2038 if (SIGPENDING(p) != 0) { 2039 while ((signum = cursig(p, &ctx)) != 0) 2040 postsig(p, signum, &ctx); 2041 } 2042 2043 /* 2044 * If P_SIGSUSPEND is still set here, then we still need to restore 2045 * the original sigmask before returning to userspace. Also, this 2046 * might unmask some pending signals, so we need to check a second 2047 * time for signals to post. 2048 */ 2049 if (p->p_flag & P_SIGSUSPEND) { 2050 p->p_sigmask = p->p_oldmask; 2051 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2052 2053 while ((signum = cursig(p, &ctx)) != 0) 2054 postsig(p, signum, &ctx); 2055 } 2056 2057 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2058 2059 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2060 } 2061 2062 int 2063 single_thread_check_locked(struct proc *p, int deep, int s) 2064 { 2065 struct process *pr = p->p_p; 2066 2067 SCHED_ASSERT_LOCKED(); 2068 2069 if (pr->ps_single == NULL || pr->ps_single == p) 2070 return (0); 2071 2072 do { 2073 /* if we're in deep, we need to unwind to the edge */ 2074 if (deep) { 2075 if (pr->ps_flags & PS_SINGLEUNWIND) 2076 return (ERESTART); 2077 if (pr->ps_flags & PS_SINGLEEXIT) 2078 return (EINTR); 2079 } 2080 2081 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2082 wakeup(&pr->ps_singlecount); 2083 2084 if (pr->ps_flags & PS_SINGLEEXIT) { 2085 SCHED_UNLOCK(s); 2086 KERNEL_LOCK(); 2087 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2088 /* NOTREACHED */ 2089 } 2090 2091 /* not exiting and don't need to unwind, so suspend */ 2092 p->p_stat = SSTOP; 2093 mi_switch(); 2094 } while (pr->ps_single != NULL); 2095 2096 return (0); 2097 } 2098 2099 int 2100 single_thread_check(struct proc *p, int deep) 2101 { 2102 int s, error; 2103 2104 SCHED_LOCK(s); 2105 error = single_thread_check_locked(p, deep, s); 2106 SCHED_UNLOCK(s); 2107 2108 return error; 2109 } 2110 2111 /* 2112 * Stop other threads in the process. The mode controls how and 2113 * where the other threads should stop: 2114 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2115 * single_thread_clear()) 2116 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2117 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2118 * - SINGLE_EXIT: unwind to kernel boundary and exit 2119 */ 2120 int 2121 single_thread_set(struct proc *p, int flags) 2122 { 2123 struct process *pr = p->p_p; 2124 struct proc *q; 2125 int error, s, mode = flags & SINGLE_MASK; 2126 2127 KASSERT(curproc == p); 2128 2129 SCHED_LOCK(s); 2130 error = single_thread_check_locked(p, flags & SINGLE_DEEP, s); 2131 if (error) { 2132 SCHED_UNLOCK(s); 2133 return error; 2134 } 2135 2136 switch (mode) { 2137 case SINGLE_SUSPEND: 2138 break; 2139 case SINGLE_UNWIND: 2140 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2141 break; 2142 case SINGLE_EXIT: 2143 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2144 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2145 break; 2146 #ifdef DIAGNOSTIC 2147 default: 2148 panic("single_thread_mode = %d", mode); 2149 #endif 2150 } 2151 pr->ps_singlecount = 0; 2152 membar_producer(); 2153 pr->ps_single = p; 2154 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2155 if (q == p) 2156 continue; 2157 if (q->p_flag & P_WEXIT) { 2158 if (mode == SINGLE_EXIT) { 2159 if (q->p_stat == SSTOP) { 2160 unsleep(q); 2161 setrunnable(q); 2162 atomic_inc_int(&pr->ps_singlecount); 2163 } 2164 } 2165 continue; 2166 } 2167 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2168 switch (q->p_stat) { 2169 case SIDL: 2170 case SRUN: 2171 atomic_inc_int(&pr->ps_singlecount); 2172 break; 2173 case SSLEEP: 2174 /* if it's not interruptible, then just have to wait */ 2175 if (q->p_flag & P_SINTR) { 2176 /* merely need to suspend? just stop it */ 2177 if (mode == SINGLE_SUSPEND) { 2178 q->p_stat = SSTOP; 2179 break; 2180 } 2181 /* need to unwind or exit, so wake it */ 2182 unsleep(q); 2183 setrunnable(q); 2184 } 2185 atomic_inc_int(&pr->ps_singlecount); 2186 break; 2187 case SSTOP: 2188 if (mode == SINGLE_EXIT) { 2189 unsleep(q); 2190 setrunnable(q); 2191 atomic_inc_int(&pr->ps_singlecount); 2192 } 2193 break; 2194 case SDEAD: 2195 break; 2196 case SONPROC: 2197 atomic_inc_int(&pr->ps_singlecount); 2198 signotify(q); 2199 break; 2200 } 2201 } 2202 SCHED_UNLOCK(s); 2203 2204 if ((flags & SINGLE_NOWAIT) == 0) 2205 single_thread_wait(pr, 1); 2206 2207 return 0; 2208 } 2209 2210 /* 2211 * Wait for other threads to stop. If recheck is false then the function 2212 * returns non-zero if the caller needs to restart the check else 0 is 2213 * returned. If recheck is true the return value is always 0. 2214 */ 2215 int 2216 single_thread_wait(struct process *pr, int recheck) 2217 { 2218 int wait; 2219 2220 /* wait until they're all suspended */ 2221 wait = pr->ps_singlecount > 0; 2222 while (wait) { 2223 sleep_setup(&pr->ps_singlecount, PWAIT, "suspend"); 2224 wait = pr->ps_singlecount > 0; 2225 sleep_finish(0, wait); 2226 if (!recheck) 2227 break; 2228 } 2229 2230 return wait; 2231 } 2232 2233 void 2234 single_thread_clear(struct proc *p, int flag) 2235 { 2236 struct process *pr = p->p_p; 2237 struct proc *q; 2238 int s; 2239 2240 KASSERT(pr->ps_single == p); 2241 KASSERT(curproc == p); 2242 2243 SCHED_LOCK(s); 2244 pr->ps_single = NULL; 2245 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2246 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2247 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2248 continue; 2249 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2250 2251 /* 2252 * if the thread was only stopped for single threading 2253 * then clearing that either makes it runnable or puts 2254 * it back into some sleep queue 2255 */ 2256 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2257 if (q->p_wchan == NULL) 2258 setrunnable(q); 2259 else { 2260 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2261 q->p_stat = SSLEEP; 2262 } 2263 } 2264 } 2265 SCHED_UNLOCK(s); 2266 } 2267 2268 void 2269 sigio_del(struct sigiolst *rmlist) 2270 { 2271 struct sigio *sigio; 2272 2273 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2274 LIST_REMOVE(sigio, sio_pgsigio); 2275 crfree(sigio->sio_ucred); 2276 free(sigio, M_SIGIO, sizeof(*sigio)); 2277 } 2278 } 2279 2280 void 2281 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2282 { 2283 struct sigio *sigio; 2284 2285 MUTEX_ASSERT_LOCKED(&sigio_lock); 2286 2287 sigio = sir->sir_sigio; 2288 if (sigio != NULL) { 2289 KASSERT(sigio->sio_myref == sir); 2290 sir->sir_sigio = NULL; 2291 2292 if (sigio->sio_pgid > 0) 2293 sigio->sio_proc = NULL; 2294 else 2295 sigio->sio_pgrp = NULL; 2296 LIST_REMOVE(sigio, sio_pgsigio); 2297 2298 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2299 } 2300 } 2301 2302 void 2303 sigio_free(struct sigio_ref *sir) 2304 { 2305 struct sigiolst rmlist; 2306 2307 if (sir->sir_sigio == NULL) 2308 return; 2309 2310 LIST_INIT(&rmlist); 2311 2312 mtx_enter(&sigio_lock); 2313 sigio_unlink(sir, &rmlist); 2314 mtx_leave(&sigio_lock); 2315 2316 sigio_del(&rmlist); 2317 } 2318 2319 void 2320 sigio_freelist(struct sigiolst *sigiolst) 2321 { 2322 struct sigiolst rmlist; 2323 struct sigio *sigio; 2324 2325 if (LIST_EMPTY(sigiolst)) 2326 return; 2327 2328 LIST_INIT(&rmlist); 2329 2330 mtx_enter(&sigio_lock); 2331 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2332 sigio_unlink(sigio->sio_myref, &rmlist); 2333 mtx_leave(&sigio_lock); 2334 2335 sigio_del(&rmlist); 2336 } 2337 2338 int 2339 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2340 { 2341 struct sigiolst rmlist; 2342 struct proc *p = curproc; 2343 struct pgrp *pgrp = NULL; 2344 struct process *pr = NULL; 2345 struct sigio *sigio; 2346 int error; 2347 pid_t pgid = *(int *)data; 2348 2349 if (pgid == 0) { 2350 sigio_free(sir); 2351 return (0); 2352 } 2353 2354 if (cmd == TIOCSPGRP) { 2355 if (pgid < 0) 2356 return (EINVAL); 2357 pgid = -pgid; 2358 } 2359 2360 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2361 sigio->sio_pgid = pgid; 2362 sigio->sio_ucred = crhold(p->p_ucred); 2363 sigio->sio_myref = sir; 2364 2365 LIST_INIT(&rmlist); 2366 2367 /* 2368 * The kernel lock, and not sleeping between prfind()/pgfind() and 2369 * linking of the sigio ensure that the process or process group does 2370 * not disappear unexpectedly. 2371 */ 2372 KERNEL_LOCK(); 2373 mtx_enter(&sigio_lock); 2374 2375 if (pgid > 0) { 2376 pr = prfind(pgid); 2377 if (pr == NULL) { 2378 error = ESRCH; 2379 goto fail; 2380 } 2381 2382 /* 2383 * Policy - Don't allow a process to FSETOWN a process 2384 * in another session. 2385 * 2386 * Remove this test to allow maximum flexibility or 2387 * restrict FSETOWN to the current process or process 2388 * group for maximum safety. 2389 */ 2390 if (pr->ps_session != p->p_p->ps_session) { 2391 error = EPERM; 2392 goto fail; 2393 } 2394 2395 if ((pr->ps_flags & PS_EXITING) != 0) { 2396 error = ESRCH; 2397 goto fail; 2398 } 2399 } else /* if (pgid < 0) */ { 2400 pgrp = pgfind(-pgid); 2401 if (pgrp == NULL) { 2402 error = ESRCH; 2403 goto fail; 2404 } 2405 2406 /* 2407 * Policy - Don't allow a process to FSETOWN a process 2408 * in another session. 2409 * 2410 * Remove this test to allow maximum flexibility or 2411 * restrict FSETOWN to the current process or process 2412 * group for maximum safety. 2413 */ 2414 if (pgrp->pg_session != p->p_p->ps_session) { 2415 error = EPERM; 2416 goto fail; 2417 } 2418 } 2419 2420 if (pgid > 0) { 2421 sigio->sio_proc = pr; 2422 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2423 } else { 2424 sigio->sio_pgrp = pgrp; 2425 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2426 } 2427 2428 sigio_unlink(sir, &rmlist); 2429 sir->sir_sigio = sigio; 2430 2431 mtx_leave(&sigio_lock); 2432 KERNEL_UNLOCK(); 2433 2434 sigio_del(&rmlist); 2435 2436 return (0); 2437 2438 fail: 2439 mtx_leave(&sigio_lock); 2440 KERNEL_UNLOCK(); 2441 2442 crfree(sigio->sio_ucred); 2443 free(sigio, M_SIGIO, sizeof(*sigio)); 2444 2445 return (error); 2446 } 2447 2448 void 2449 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2450 { 2451 struct sigio *sigio; 2452 pid_t pgid = 0; 2453 2454 mtx_enter(&sigio_lock); 2455 sigio = sir->sir_sigio; 2456 if (sigio != NULL) 2457 pgid = sigio->sio_pgid; 2458 mtx_leave(&sigio_lock); 2459 2460 if (cmd == TIOCGPGRP) 2461 pgid = -pgid; 2462 2463 *(int *)data = pgid; 2464 } 2465 2466 void 2467 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2468 { 2469 struct sigiolst rmlist; 2470 struct sigio *newsigio, *sigio; 2471 2472 sigio_free(dst); 2473 2474 if (src->sir_sigio == NULL) 2475 return; 2476 2477 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2478 LIST_INIT(&rmlist); 2479 2480 mtx_enter(&sigio_lock); 2481 2482 sigio = src->sir_sigio; 2483 if (sigio == NULL) { 2484 mtx_leave(&sigio_lock); 2485 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2486 return; 2487 } 2488 2489 newsigio->sio_pgid = sigio->sio_pgid; 2490 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2491 newsigio->sio_myref = dst; 2492 if (newsigio->sio_pgid > 0) { 2493 newsigio->sio_proc = sigio->sio_proc; 2494 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2495 sio_pgsigio); 2496 } else { 2497 newsigio->sio_pgrp = sigio->sio_pgrp; 2498 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2499 sio_pgsigio); 2500 } 2501 2502 sigio_unlink(dst, &rmlist); 2503 dst->sir_sigio = newsigio; 2504 2505 mtx_leave(&sigio_lock); 2506 2507 sigio_del(&rmlist); 2508 } 2509