1 /* $OpenBSD: kern_sig.c,v 1.334 2024/07/24 15:31:08 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 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 847 pr->ps_xsig = signum; 848 849 SCHED_LOCK(); 850 proc_stop(p, 1); 851 SCHED_UNLOCK(); 852 853 signum = pr->ps_xsig; 854 single_thread_clear(p, 0); 855 856 /* 857 * If we are no longer being traced, or the parent 858 * didn't give us a signal, skip sending the signal. 859 */ 860 if ((pr->ps_flags & PS_TRACED) == 0 || 861 signum == 0) 862 return; 863 864 /* update signal info */ 865 p->p_sisig = signum; 866 mask = sigmask(signum); 867 } 868 869 /* 870 * Signals like SIGBUS and SIGSEGV should not, when 871 * generated by the kernel, be ignorable or blockable. 872 * If it is and we're not being traced, then just kill 873 * the process. 874 * After vfs_shutdown(9), init(8) cannot receive signals 875 * because new code pages of the signal handler cannot be 876 * mapped from halted storage. init(8) may not die or the 877 * kernel panics. Better loop between signal handler and 878 * page fault trap until the machine is halted. 879 */ 880 if ((pr->ps_flags & PS_TRACED) == 0 && 881 (sigprop[signum] & SA_KILL) && 882 ((p->p_sigmask & mask) || ctx.sig_ignore) && 883 pr->ps_pid != 1) { 884 KERNEL_LOCK(); 885 sigexit(p, signum); 886 /* NOTREACHED */ 887 } 888 KERNEL_LOCK(); 889 ptsignal(p, signum, STHREAD); 890 KERNEL_UNLOCK(); 891 } 892 } 893 894 /* 895 * Send the signal to the process. If the signal has an action, the action 896 * is usually performed by the target process rather than the caller; we add 897 * the signal to the set of pending signals for the process. 898 * 899 * Exceptions: 900 * o When a stop signal is sent to a sleeping process that takes the 901 * default action, the process is stopped without awakening it. 902 * o SIGCONT restarts stopped processes (or puts them back to sleep) 903 * regardless of the signal action (eg, blocked or ignored). 904 * 905 * Other ignored signals are discarded immediately. 906 */ 907 void 908 psignal(struct proc *p, int signum) 909 { 910 ptsignal(p, signum, SPROCESS); 911 } 912 913 /* 914 * type = SPROCESS process signal, can be diverted (sigwait()) 915 * type = STHREAD thread signal, but should be propagated if unhandled 916 * type = SPROPAGATED propagated to this thread, so don't propagate again 917 */ 918 void 919 ptsignal(struct proc *p, int signum, enum signal_type type) 920 { 921 int prop; 922 sig_t action, altaction = SIG_DFL; 923 sigset_t mask, sigmask; 924 int *siglist; 925 struct process *pr = p->p_p; 926 struct proc *q; 927 int wakeparent = 0; 928 929 KERNEL_ASSERT_LOCKED(); 930 931 #ifdef DIAGNOSTIC 932 if ((u_int)signum >= NSIG || signum == 0) 933 panic("psignal signal number"); 934 #endif 935 936 /* Ignore signal if the target process is exiting */ 937 if (pr->ps_flags & PS_EXITING) 938 return; 939 940 mask = sigmask(signum); 941 sigmask = READ_ONCE(p->p_sigmask); 942 943 if (type == SPROCESS) { 944 sigset_t tmpmask; 945 946 /* Accept SIGKILL to coredumping processes */ 947 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 948 atomic_setbits_int(&pr->ps_siglist, mask); 949 return; 950 } 951 952 /* 953 * If the current thread can process the signal 954 * immediately (it's unblocked) then have it take it. 955 */ 956 q = curproc; 957 tmpmask = READ_ONCE(q->p_sigmask); 958 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 959 (tmpmask & mask) == 0) { 960 p = q; 961 sigmask = tmpmask; 962 } else { 963 /* 964 * A process-wide signal can be diverted to a 965 * different thread that's in sigwait() for this 966 * signal. If there isn't such a thread, then 967 * pick a thread that doesn't have it blocked so 968 * that the stop/kill consideration isn't 969 * delayed. Otherwise, mark it pending on the 970 * main thread. 971 */ 972 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 973 974 /* ignore exiting threads */ 975 if (q->p_flag & P_WEXIT) 976 continue; 977 978 /* skip threads that have the signal blocked */ 979 tmpmask = READ_ONCE(q->p_sigmask); 980 if ((tmpmask & mask) != 0) 981 continue; 982 983 /* okay, could send to this thread */ 984 p = q; 985 sigmask = tmpmask; 986 987 /* 988 * sigsuspend, sigwait, ppoll/pselect, etc? 989 * Definitely go to this thread, as it's 990 * already blocked in the kernel. 991 */ 992 if (q->p_flag & P_SIGSUSPEND) 993 break; 994 } 995 } 996 } 997 998 if (type != SPROPAGATED) 999 knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); 1000 1001 prop = sigprop[signum]; 1002 1003 /* 1004 * If proc is traced, always give parent a chance. 1005 */ 1006 if (pr->ps_flags & PS_TRACED) { 1007 action = SIG_DFL; 1008 } else { 1009 sigset_t sigcatch, sigignore; 1010 1011 /* 1012 * If the signal is being ignored, 1013 * then we forget about it immediately. 1014 * (Note: we don't set SIGCONT in ps_sigignore, 1015 * and if it is set to SIG_IGN, 1016 * action will be SIG_DFL here.) 1017 */ 1018 mtx_enter(&pr->ps_mtx); 1019 sigignore = pr->ps_sigacts->ps_sigignore; 1020 sigcatch = pr->ps_sigacts->ps_sigcatch; 1021 mtx_leave(&pr->ps_mtx); 1022 1023 if (sigignore & mask) 1024 return; 1025 if (sigmask & mask) { 1026 action = SIG_HOLD; 1027 if (sigcatch & mask) 1028 altaction = SIG_CATCH; 1029 } else if (sigcatch & mask) { 1030 action = SIG_CATCH; 1031 } else { 1032 action = SIG_DFL; 1033 1034 if (prop & SA_KILL && pr->ps_nice > NZERO) 1035 pr->ps_nice = NZERO; 1036 1037 /* 1038 * If sending a tty stop signal to a member of an 1039 * orphaned process group, discard the signal here if 1040 * the action is default; don't stop the process below 1041 * if sleeping, and don't clear any pending SIGCONT. 1042 */ 1043 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1044 return; 1045 } 1046 } 1047 /* 1048 * If delivered to process, mark as pending there. Continue and stop 1049 * signals will be propagated to all threads. So they are always 1050 * marked at thread level. 1051 */ 1052 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1053 if (prop & (SA_CONT | SA_STOP)) 1054 siglist = &p->p_siglist; 1055 1056 /* 1057 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1058 */ 1059 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1060 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1061 if (q != p) 1062 ptsignal(q, signum, SPROPAGATED); 1063 1064 SCHED_LOCK(); 1065 1066 switch (p->p_stat) { 1067 1068 case SSTOP: 1069 /* 1070 * If traced process is already stopped, 1071 * then no further action is necessary. 1072 */ 1073 if (pr->ps_flags & PS_TRACED) 1074 goto out; 1075 1076 /* 1077 * Kill signal always sets processes running. 1078 */ 1079 if (signum == SIGKILL) { 1080 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1081 /* Raise priority to at least PUSER. */ 1082 if (p->p_usrpri > PUSER) 1083 p->p_usrpri = PUSER; 1084 unsleep(p); 1085 setrunnable(p); 1086 goto out; 1087 } 1088 1089 if (prop & SA_CONT) { 1090 /* 1091 * If SIGCONT is default (or ignored), we continue the 1092 * process but don't leave the signal in p_siglist, as 1093 * it has no further action. If SIGCONT is held, we 1094 * continue the process and leave the signal in 1095 * p_siglist. If the process catches SIGCONT, let it 1096 * handle the signal itself. If it isn't waiting on 1097 * an event, then it goes back to run state. 1098 * Otherwise, process goes back to sleep state. 1099 */ 1100 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1101 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1102 wakeparent = 1; 1103 if (action == SIG_DFL) 1104 mask = 0; 1105 if (action == SIG_CATCH) { 1106 /* Raise priority to at least PUSER. */ 1107 if (p->p_usrpri > PUSER) 1108 p->p_usrpri = PUSER; 1109 unsleep(p); 1110 setrunnable(p); 1111 goto out; 1112 } 1113 if (p->p_wchan == NULL) { 1114 unsleep(p); 1115 setrunnable(p); 1116 goto out; 1117 } 1118 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1119 p->p_stat = SSLEEP; 1120 goto out; 1121 } 1122 1123 /* 1124 * Defer further processing for signals which are held, 1125 * except that stopped processes must be continued by SIGCONT. 1126 */ 1127 if (action == SIG_HOLD) 1128 goto out; 1129 1130 if (prop & SA_STOP) { 1131 /* 1132 * Already stopped, don't need to stop again. 1133 * (If we did the shell could get confused.) 1134 */ 1135 mask = 0; 1136 goto out; 1137 } 1138 1139 /* 1140 * If process is sleeping interruptibly, then simulate a 1141 * wakeup so that when it is continued, it will be made 1142 * runnable and can look at the signal. But don't make 1143 * the process runnable, leave it stopped. 1144 */ 1145 if (p->p_flag & P_SINTR) 1146 unsleep(p); 1147 goto out; 1148 1149 case SSLEEP: 1150 /* 1151 * If process is sleeping uninterruptibly 1152 * we can't interrupt the sleep... the signal will 1153 * be noticed when the process returns through 1154 * trap() or syscall(). 1155 */ 1156 if ((p->p_flag & P_SINTR) == 0) 1157 goto out; 1158 /* 1159 * Process is sleeping and traced... make it runnable 1160 * so it can discover the signal in cursig() and stop 1161 * for the parent. 1162 */ 1163 if (pr->ps_flags & PS_TRACED) { 1164 unsleep(p); 1165 setrunnable(p); 1166 goto out; 1167 } 1168 1169 /* 1170 * Recheck sigmask before waking up the process, 1171 * there is a chance that while sending the signal 1172 * the process changed sigmask and went to sleep. 1173 */ 1174 sigmask = READ_ONCE(p->p_sigmask); 1175 if (sigmask & mask) 1176 goto out; 1177 else if (action == SIG_HOLD) { 1178 /* signal got unmasked, get proper action */ 1179 action = altaction; 1180 1181 if (action == SIG_DFL) { 1182 if (prop & SA_KILL && pr->ps_nice > NZERO) 1183 pr->ps_nice = NZERO; 1184 1185 /* 1186 * Discard tty stop signals sent to an 1187 * orphaned process group, see above. 1188 */ 1189 if (prop & SA_TTYSTOP && 1190 pr->ps_pgrp->pg_jobc == 0) { 1191 mask = 0; 1192 prop = 0; 1193 goto out; 1194 } 1195 } 1196 } 1197 1198 /* 1199 * If SIGCONT is default (or ignored) and process is 1200 * asleep, we are finished; the process should not 1201 * be awakened. 1202 */ 1203 if ((prop & SA_CONT) && action == SIG_DFL) { 1204 mask = 0; 1205 goto out; 1206 } 1207 /* 1208 * When a sleeping process receives a stop 1209 * signal, process immediately if possible. 1210 */ 1211 if ((prop & SA_STOP) && action == SIG_DFL) { 1212 /* 1213 * If a child holding parent blocked, 1214 * stopping could cause deadlock. 1215 */ 1216 if (pr->ps_flags & PS_PPWAIT) 1217 goto out; 1218 mask = 0; 1219 pr->ps_xsig = signum; 1220 proc_stop(p, 0); 1221 goto out; 1222 } 1223 /* 1224 * All other (caught or default) signals 1225 * cause the process to run. 1226 * Raise priority to at least PUSER. 1227 */ 1228 if (p->p_usrpri > PUSER) 1229 p->p_usrpri = PUSER; 1230 unsleep(p); 1231 setrunnable(p); 1232 goto out; 1233 /* NOTREACHED */ 1234 1235 case SONPROC: 1236 if (action == SIG_HOLD) 1237 goto out; 1238 1239 /* set siglist before issuing the ast */ 1240 atomic_setbits_int(siglist, mask); 1241 mask = 0; 1242 signotify(p); 1243 /* FALLTHROUGH */ 1244 default: 1245 /* 1246 * SRUN, SIDL, SDEAD do nothing with the signal, 1247 * other than kicking ourselves if we are running. 1248 * It will either never be noticed, or noticed very soon. 1249 */ 1250 goto out; 1251 } 1252 /* NOTREACHED */ 1253 1254 out: 1255 /* finally adjust siglist */ 1256 if (mask) 1257 atomic_setbits_int(siglist, mask); 1258 if (prop & SA_CONT) { 1259 atomic_clearbits_int(siglist, STOPSIGMASK); 1260 } 1261 if (prop & SA_STOP) { 1262 atomic_clearbits_int(siglist, CONTSIGMASK); 1263 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1264 } 1265 1266 SCHED_UNLOCK(); 1267 if (wakeparent) 1268 wakeup(pr->ps_pptr); 1269 } 1270 1271 /* fill the signal context which should be used by postsig() and issignal() */ 1272 void 1273 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1274 { 1275 struct sigacts *ps = p->p_p->ps_sigacts; 1276 sigset_t mask; 1277 1278 mtx_enter(&p->p_p->ps_mtx); 1279 mask = sigmask(signum); 1280 sctx->sig_action = ps->ps_sigact[signum]; 1281 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1282 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1283 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1284 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1285 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1286 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1287 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1288 mtx_leave(&p->p_p->ps_mtx); 1289 } 1290 1291 /* 1292 * Determine signal that should be delivered to process p, the current 1293 * process, 0 if none. 1294 * 1295 * If the current process has received a signal (should be caught or cause 1296 * termination, should interrupt current syscall), return the signal number. 1297 * Stop signals with default action are processed immediately, then cleared; 1298 * they aren't returned. This is checked after each entry to the system for 1299 * a syscall or trap. The normal call sequence is 1300 * 1301 * while (signum = cursig(curproc, &ctx)) 1302 * postsig(signum, &ctx); 1303 * 1304 * Assumes that if the P_SINTR flag is set, we're holding both the 1305 * kernel and scheduler locks. 1306 */ 1307 int 1308 cursig(struct proc *p, struct sigctx *sctx) 1309 { 1310 struct process *pr = p->p_p; 1311 int signum, mask, prop; 1312 sigset_t ps_siglist; 1313 1314 KASSERT(p == curproc); 1315 1316 for (;;) { 1317 ps_siglist = READ_ONCE(pr->ps_siglist); 1318 membar_consumer(); 1319 mask = SIGPENDING(p); 1320 if (pr->ps_flags & PS_PPWAIT) 1321 mask &= ~STOPSIGMASK; 1322 if (mask == 0) /* no signal to send */ 1323 return (0); 1324 signum = ffs((long)mask); 1325 mask = sigmask(signum); 1326 1327 /* take the signal! */ 1328 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1329 ps_siglist & ~mask) != ps_siglist) { 1330 /* lost race taking the process signal, restart */ 1331 continue; 1332 } 1333 atomic_clearbits_int(&p->p_siglist, mask); 1334 setsigctx(p, signum, sctx); 1335 1336 /* 1337 * We should see pending but ignored signals 1338 * only if PS_TRACED was on when they were posted. 1339 */ 1340 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1341 continue; 1342 1343 /* 1344 * If traced, always stop, and stay stopped until released 1345 * by the debugger. If our parent process is waiting for 1346 * us, don't hang as we could deadlock. 1347 */ 1348 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1349 signum != SIGKILL) { 1350 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1351 pr->ps_xsig = signum; 1352 1353 SCHED_LOCK(); 1354 proc_stop(p, 1); 1355 SCHED_UNLOCK(); 1356 1357 /* 1358 * re-take the signal before releasing 1359 * the other threads. Must check the continue 1360 * conditions below and only take the signal if 1361 * those are not true. 1362 */ 1363 signum = pr->ps_xsig; 1364 mask = sigmask(signum); 1365 setsigctx(p, signum, sctx); 1366 if (!((pr->ps_flags & PS_TRACED) == 0 || 1367 signum == 0 || 1368 (p->p_sigmask & mask) != 0)) { 1369 atomic_clearbits_int(&p->p_siglist, mask); 1370 atomic_clearbits_int(&pr->ps_siglist, mask); 1371 } 1372 1373 single_thread_clear(p, 0); 1374 1375 /* 1376 * If we are no longer being traced, or the parent 1377 * didn't give us a signal, look for more signals. 1378 */ 1379 if ((pr->ps_flags & PS_TRACED) == 0 || 1380 signum == 0) 1381 continue; 1382 1383 /* 1384 * If the new signal is being masked, look for other 1385 * signals. 1386 */ 1387 if ((p->p_sigmask & mask) != 0) 1388 continue; 1389 1390 } 1391 1392 prop = sigprop[signum]; 1393 1394 /* 1395 * Decide whether the signal should be returned. 1396 * Return the signal's number, or fall through 1397 * to clear it from the pending mask. 1398 */ 1399 switch ((long)sctx->sig_action) { 1400 case (long)SIG_DFL: 1401 /* 1402 * Don't take default actions on system processes. 1403 */ 1404 if (pr->ps_pid <= 1) { 1405 #ifdef DIAGNOSTIC 1406 /* 1407 * Are you sure you want to ignore SIGSEGV 1408 * in init? XXX 1409 */ 1410 printf("Process (pid %d) got signal" 1411 " %d\n", pr->ps_pid, signum); 1412 #endif 1413 break; /* == ignore */ 1414 } 1415 /* 1416 * If there is a pending stop signal to process 1417 * with default action, stop here, 1418 * then clear the signal. However, 1419 * if process is member of an orphaned 1420 * process group, ignore tty stop signals. 1421 */ 1422 if (prop & SA_STOP) { 1423 if (pr->ps_flags & PS_TRACED || 1424 (pr->ps_pgrp->pg_jobc == 0 && 1425 prop & SA_TTYSTOP)) 1426 break; /* == ignore */ 1427 pr->ps_xsig = signum; 1428 SCHED_LOCK(); 1429 proc_stop(p, 1); 1430 SCHED_UNLOCK(); 1431 break; 1432 } else if (prop & SA_IGNORE) { 1433 /* 1434 * Except for SIGCONT, shouldn't get here. 1435 * Default action is to ignore; drop it. 1436 */ 1437 break; /* == ignore */ 1438 } else 1439 goto keep; 1440 /* NOTREACHED */ 1441 case (long)SIG_IGN: 1442 /* 1443 * Masking above should prevent us ever trying 1444 * to take action on an ignored signal other 1445 * than SIGCONT, unless process is traced. 1446 */ 1447 if ((prop & SA_CONT) == 0 && 1448 (pr->ps_flags & PS_TRACED) == 0) 1449 printf("%s\n", __func__); 1450 break; /* == ignore */ 1451 default: 1452 /* 1453 * This signal has an action, let 1454 * postsig() process it. 1455 */ 1456 goto keep; 1457 } 1458 } 1459 /* NOTREACHED */ 1460 1461 keep: 1462 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1463 return (signum); 1464 } 1465 1466 /* 1467 * Put the argument process into the stopped state and notify the parent 1468 * via wakeup. Signals are handled elsewhere. The process must not be 1469 * on the run queue. 1470 */ 1471 void 1472 proc_stop(struct proc *p, int sw) 1473 { 1474 struct process *pr = p->p_p; 1475 1476 #ifdef MULTIPROCESSOR 1477 SCHED_ASSERT_LOCKED(); 1478 #endif 1479 /* do not stop exiting procs */ 1480 if (ISSET(p->p_flag, P_WEXIT)) 1481 return; 1482 1483 p->p_stat = SSTOP; 1484 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1485 atomic_setbits_int(&pr->ps_flags, PS_STOPPING); 1486 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1487 /* 1488 * We need this soft interrupt to be handled fast. 1489 * Extra calls to softclock don't hurt. 1490 */ 1491 softintr_schedule(proc_stop_si); 1492 if (sw) 1493 mi_switch(); 1494 } 1495 1496 /* 1497 * Called from a soft interrupt to send signals to the parents of stopped 1498 * processes. 1499 * We can't do this in proc_stop because it's called with nasty locks held 1500 * and we would need recursive scheduler lock to deal with that. 1501 */ 1502 void 1503 proc_stop_sweep(void *v) 1504 { 1505 struct process *pr; 1506 1507 LIST_FOREACH(pr, &allprocess, ps_list) { 1508 if ((pr->ps_flags & PS_STOPPING) == 0) 1509 continue; 1510 atomic_clearbits_int(&pr->ps_flags, PS_STOPPING); 1511 1512 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1513 prsignal(pr->ps_pptr, SIGCHLD); 1514 wakeup(pr->ps_pptr); 1515 } 1516 } 1517 1518 /* 1519 * Take the action for the specified signal 1520 * from the current set of pending signals. 1521 */ 1522 void 1523 postsig(struct proc *p, int signum, struct sigctx *sctx) 1524 { 1525 u_long trapno; 1526 int mask, returnmask; 1527 siginfo_t si; 1528 union sigval sigval; 1529 int code; 1530 1531 KASSERT(signum != 0); 1532 1533 mask = sigmask(signum); 1534 atomic_clearbits_int(&p->p_siglist, mask); 1535 sigval.sival_ptr = NULL; 1536 1537 if (p->p_sisig != signum) { 1538 trapno = 0; 1539 code = SI_USER; 1540 sigval.sival_ptr = NULL; 1541 } else { 1542 trapno = p->p_sitrapno; 1543 code = p->p_sicode; 1544 sigval = p->p_sigval; 1545 } 1546 initsiginfo(&si, signum, trapno, code, sigval); 1547 1548 #ifdef KTRACE 1549 if (KTRPOINT(p, KTR_PSIG)) { 1550 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1551 p->p_oldmask : p->p_sigmask, code, &si); 1552 } 1553 #endif 1554 if (sctx->sig_action == SIG_DFL) { 1555 /* 1556 * Default action, where the default is to kill 1557 * the process. (Other cases were ignored above.) 1558 */ 1559 KERNEL_LOCK(); 1560 sigexit(p, signum); 1561 /* NOTREACHED */ 1562 } else { 1563 /* 1564 * If we get here, the signal must be caught. 1565 */ 1566 #ifdef DIAGNOSTIC 1567 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1568 panic("postsig action"); 1569 #endif 1570 /* 1571 * Set the new mask value and also defer further 1572 * occurrences of this signal. 1573 * 1574 * Special case: user has done a sigpause. Here the 1575 * current mask is not of interest, but rather the 1576 * mask from before the sigpause is what we want 1577 * restored after the signal processing is completed. 1578 */ 1579 if (p->p_flag & P_SIGSUSPEND) { 1580 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1581 returnmask = p->p_oldmask; 1582 } else { 1583 returnmask = p->p_sigmask; 1584 } 1585 if (p->p_sisig == signum) { 1586 p->p_sisig = 0; 1587 p->p_sitrapno = 0; 1588 p->p_sicode = SI_USER; 1589 p->p_sigval.sival_ptr = NULL; 1590 } 1591 1592 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1593 sctx->sig_info, sctx->sig_onstack)) { 1594 KERNEL_LOCK(); 1595 sigexit(p, SIGILL); 1596 /* NOTREACHED */ 1597 } 1598 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1599 } 1600 } 1601 1602 /* 1603 * Force the current process to exit with the specified signal, dumping core 1604 * if appropriate. We bypass the normal tests for masked and caught signals, 1605 * allowing unrecoverable failures to terminate the process without changing 1606 * signal state. Mark the accounting record with the signal termination. 1607 * If dumping core, save the signal number for the debugger. Calls exit and 1608 * does not return. 1609 */ 1610 void 1611 sigexit(struct proc *p, int signum) 1612 { 1613 /* Mark process as going away */ 1614 atomic_setbits_int(&p->p_flag, P_WEXIT); 1615 1616 p->p_p->ps_acflag |= AXSIG; 1617 if (sigprop[signum] & SA_CORE) { 1618 p->p_sisig = signum; 1619 1620 /* if there are other threads, pause them */ 1621 if (P_HASSIBLING(p)) 1622 single_thread_set(p, SINGLE_UNWIND); 1623 1624 if (coredump(p) == 0) 1625 signum |= WCOREFLAG; 1626 } 1627 exit1(p, 0, signum, EXIT_NORMAL); 1628 /* NOTREACHED */ 1629 } 1630 1631 /* 1632 * Send uncatchable SIGABRT for coredump. 1633 */ 1634 void 1635 sigabort(struct proc *p) 1636 { 1637 struct sigaction sa; 1638 1639 KASSERT(p == curproc || panicstr || db_active); 1640 1641 memset(&sa, 0, sizeof sa); 1642 sa.sa_handler = SIG_DFL; 1643 setsigvec(p, SIGABRT, &sa); 1644 CLR(p->p_sigmask, sigmask(SIGABRT)); 1645 psignal(p, SIGABRT); 1646 } 1647 1648 /* 1649 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1650 * thread, and 0 otherwise. 1651 */ 1652 int 1653 sigismasked(struct proc *p, int sig) 1654 { 1655 struct process *pr = p->p_p; 1656 int rv; 1657 1658 KASSERT(p == curproc); 1659 1660 mtx_enter(&pr->ps_mtx); 1661 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1662 (p->p_sigmask & sigmask(sig)); 1663 mtx_leave(&pr->ps_mtx); 1664 1665 return !!rv; 1666 } 1667 1668 struct coredump_iostate { 1669 struct proc *io_proc; 1670 struct vnode *io_vp; 1671 struct ucred *io_cred; 1672 off_t io_offset; 1673 }; 1674 1675 /* 1676 * Dump core, into a file named "progname.core", unless the process was 1677 * setuid/setgid. 1678 */ 1679 int 1680 coredump(struct proc *p) 1681 { 1682 #ifdef SMALL_KERNEL 1683 return EPERM; 1684 #else 1685 struct process *pr = p->p_p; 1686 struct vnode *vp; 1687 struct ucred *cred = p->p_ucred; 1688 struct vmspace *vm = p->p_vmspace; 1689 struct nameidata nd; 1690 struct vattr vattr; 1691 struct coredump_iostate io; 1692 int error, len, incrash = 0; 1693 char *name; 1694 const char *dir = "/var/crash"; 1695 1696 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1697 1698 #ifdef PMAP_CHECK_COPYIN 1699 /* disable copyin checks, so we can write out text sections if needed */ 1700 p->p_vmspace->vm_map.check_copyin_count = 0; 1701 #endif 1702 1703 /* Don't dump if will exceed file size limit. */ 1704 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1705 return (EFBIG); 1706 1707 name = pool_get(&namei_pool, PR_WAITOK); 1708 1709 /* 1710 * If the process has inconsistent uids, nosuidcoredump 1711 * determines coredump placement policy. 1712 */ 1713 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1714 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1715 if (nosuidcoredump == 3) { 1716 /* 1717 * If the program directory does not exist, dumps of 1718 * that core will silently fail. 1719 */ 1720 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1721 dir, pr->ps_comm, pr->ps_pid); 1722 incrash = KERNELPATH; 1723 } else if (nosuidcoredump == 2) { 1724 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1725 dir, pr->ps_comm); 1726 incrash = KERNELPATH; 1727 } else { 1728 pool_put(&namei_pool, name); 1729 return (EPERM); 1730 } 1731 } else 1732 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1733 1734 if (len >= MAXPATHLEN) { 1735 pool_put(&namei_pool, name); 1736 return (EACCES); 1737 } 1738 1739 /* 1740 * Control the UID used to write out. The normal case uses 1741 * the real UID. If the sugid case is going to write into the 1742 * controlled directory, we do so as root. 1743 */ 1744 if (incrash == 0) { 1745 cred = crdup(cred); 1746 cred->cr_uid = cred->cr_ruid; 1747 cred->cr_gid = cred->cr_rgid; 1748 } else { 1749 if (p->p_fd->fd_rdir) { 1750 vrele(p->p_fd->fd_rdir); 1751 p->p_fd->fd_rdir = NULL; 1752 } 1753 p->p_ucred = crdup(p->p_ucred); 1754 crfree(cred); 1755 cred = p->p_ucred; 1756 crhold(cred); 1757 cred->cr_uid = 0; 1758 cred->cr_gid = 0; 1759 } 1760 1761 /* incrash should be 0 or KERNELPATH only */ 1762 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1763 1764 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1765 S_IRUSR | S_IWUSR); 1766 1767 if (error) 1768 goto out; 1769 1770 /* 1771 * Don't dump to non-regular files, files with links, or files 1772 * owned by someone else. 1773 */ 1774 vp = nd.ni_vp; 1775 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1776 VOP_UNLOCK(vp); 1777 vn_close(vp, FWRITE, cred, p); 1778 goto out; 1779 } 1780 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1781 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1782 vattr.va_uid != cred->cr_uid) { 1783 error = EACCES; 1784 VOP_UNLOCK(vp); 1785 vn_close(vp, FWRITE, cred, p); 1786 goto out; 1787 } 1788 VATTR_NULL(&vattr); 1789 vattr.va_size = 0; 1790 VOP_SETATTR(vp, &vattr, cred, p); 1791 pr->ps_acflag |= ACORE; 1792 1793 io.io_proc = p; 1794 io.io_vp = vp; 1795 io.io_cred = cred; 1796 io.io_offset = 0; 1797 VOP_UNLOCK(vp); 1798 vref(vp); 1799 error = vn_close(vp, FWRITE, cred, p); 1800 if (error == 0) 1801 error = coredump_elf(p, &io); 1802 vrele(vp); 1803 out: 1804 crfree(cred); 1805 pool_put(&namei_pool, name); 1806 return (error); 1807 #endif 1808 } 1809 1810 #ifndef SMALL_KERNEL 1811 int 1812 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1813 int isvnode) 1814 { 1815 struct coredump_iostate *io = cookie; 1816 off_t coffset = 0; 1817 size_t csize; 1818 int chunk, error; 1819 1820 csize = len; 1821 do { 1822 if (sigmask(SIGKILL) & 1823 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1824 return (EINTR); 1825 1826 /* Rest of the loop sleeps with lock held, so... */ 1827 yield(); 1828 1829 chunk = MIN(csize, MAXPHYS); 1830 error = vn_rdwr(UIO_WRITE, io->io_vp, 1831 (caddr_t)data + coffset, chunk, 1832 io->io_offset + coffset, segflg, 1833 IO_UNIT, io->io_cred, NULL, io->io_proc); 1834 if (error && (error != EFAULT || !isvnode)) { 1835 struct process *pr = io->io_proc->p_p; 1836 1837 if (error == ENOSPC) 1838 log(LOG_ERR, 1839 "coredump of %s(%d) failed, filesystem full\n", 1840 pr->ps_comm, pr->ps_pid); 1841 else 1842 log(LOG_ERR, 1843 "coredump of %s(%d), write failed: errno %d\n", 1844 pr->ps_comm, pr->ps_pid, error); 1845 return (error); 1846 } 1847 1848 coffset += chunk; 1849 csize -= chunk; 1850 } while (csize > 0); 1851 1852 io->io_offset += len; 1853 return (0); 1854 } 1855 1856 void 1857 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1858 { 1859 struct coredump_iostate *io = cookie; 1860 1861 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1862 } 1863 1864 #endif /* !SMALL_KERNEL */ 1865 1866 /* 1867 * Nonexistent system call-- signal process (may want to handle it). 1868 * Flag error in case process won't see signal immediately (blocked or ignored). 1869 */ 1870 int 1871 sys_nosys(struct proc *p, void *v, register_t *retval) 1872 { 1873 ptsignal(p, SIGSYS, STHREAD); 1874 return (ENOSYS); 1875 } 1876 1877 int 1878 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1879 { 1880 struct sys___thrsigdivert_args /* { 1881 syscallarg(sigset_t) sigmask; 1882 syscallarg(siginfo_t *) info; 1883 syscallarg(const struct timespec *) timeout; 1884 } */ *uap = v; 1885 struct sigctx ctx; 1886 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1887 siginfo_t si; 1888 uint64_t nsecs = INFSLP; 1889 int timeinvalid = 0; 1890 int error = 0; 1891 1892 memset(&si, 0, sizeof(si)); 1893 1894 if (SCARG(uap, timeout) != NULL) { 1895 struct timespec ts; 1896 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1897 return (error); 1898 #ifdef KTRACE 1899 if (KTRPOINT(p, KTR_STRUCT)) 1900 ktrreltimespec(p, &ts); 1901 #endif 1902 if (!timespecisvalid(&ts)) 1903 timeinvalid = 1; 1904 else 1905 nsecs = TIMESPEC_TO_NSEC(&ts); 1906 } 1907 1908 dosigsuspend(p, p->p_sigmask &~ mask); 1909 for (;;) { 1910 si.si_signo = cursig(p, &ctx); 1911 if (si.si_signo != 0) { 1912 sigset_t smask = sigmask(si.si_signo); 1913 if (smask & mask) { 1914 atomic_clearbits_int(&p->p_siglist, smask); 1915 error = 0; 1916 break; 1917 } 1918 } 1919 1920 /* per-POSIX, delay this error until after the above */ 1921 if (timeinvalid) 1922 error = EINVAL; 1923 /* per-POSIX, return immediately if timeout is zero-valued */ 1924 if (nsecs == 0) 1925 error = EAGAIN; 1926 1927 if (error != 0) 1928 break; 1929 1930 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1931 } 1932 1933 if (error == 0) { 1934 *retval = si.si_signo; 1935 if (SCARG(uap, info) != NULL) { 1936 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1937 #ifdef KTRACE 1938 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1939 ktrsiginfo(p, &si); 1940 #endif 1941 } 1942 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1943 /* 1944 * Restarting is wrong if there's a timeout, as it'll be 1945 * for the same interval again 1946 */ 1947 error = EINTR; 1948 } 1949 1950 return (error); 1951 } 1952 1953 void 1954 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1955 { 1956 memset(si, 0, sizeof(*si)); 1957 1958 si->si_signo = sig; 1959 si->si_code = code; 1960 if (code == SI_USER) { 1961 si->si_value = val; 1962 } else { 1963 switch (sig) { 1964 case SIGSEGV: 1965 case SIGILL: 1966 case SIGBUS: 1967 case SIGFPE: 1968 si->si_addr = val.sival_ptr; 1969 si->si_trapno = trapno; 1970 break; 1971 case SIGXFSZ: 1972 break; 1973 } 1974 } 1975 } 1976 1977 int 1978 filt_sigattach(struct knote *kn) 1979 { 1980 struct process *pr = curproc->p_p; 1981 int s; 1982 1983 if (kn->kn_id >= NSIG) 1984 return EINVAL; 1985 1986 kn->kn_ptr.p_process = pr; 1987 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1988 1989 s = splhigh(); 1990 klist_insert_locked(&pr->ps_klist, kn); 1991 splx(s); 1992 1993 return (0); 1994 } 1995 1996 void 1997 filt_sigdetach(struct knote *kn) 1998 { 1999 struct process *pr = kn->kn_ptr.p_process; 2000 int s; 2001 2002 s = splhigh(); 2003 klist_remove_locked(&pr->ps_klist, kn); 2004 splx(s); 2005 } 2006 2007 /* 2008 * signal knotes are shared with proc knotes, so we apply a mask to 2009 * the hint in order to differentiate them from process hints. This 2010 * could be avoided by using a signal-specific knote list, but probably 2011 * isn't worth the trouble. 2012 */ 2013 int 2014 filt_signal(struct knote *kn, long hint) 2015 { 2016 2017 if (hint & NOTE_SIGNAL) { 2018 hint &= ~NOTE_SIGNAL; 2019 2020 if (kn->kn_id == hint) 2021 kn->kn_data++; 2022 } 2023 return (kn->kn_data != 0); 2024 } 2025 2026 void 2027 userret(struct proc *p) 2028 { 2029 struct sigctx ctx; 2030 int signum; 2031 2032 if (p->p_flag & P_SUSPSINGLE) 2033 single_thread_check(p, 0); 2034 2035 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 2036 if (p->p_flag & P_PROFPEND) { 2037 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 2038 KERNEL_LOCK(); 2039 psignal(p, SIGPROF); 2040 KERNEL_UNLOCK(); 2041 } 2042 if (p->p_flag & P_ALRMPEND) { 2043 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 2044 KERNEL_LOCK(); 2045 psignal(p, SIGVTALRM); 2046 KERNEL_UNLOCK(); 2047 } 2048 2049 if (SIGPENDING(p) != 0) { 2050 while ((signum = cursig(p, &ctx)) != 0) 2051 postsig(p, signum, &ctx); 2052 } 2053 2054 /* 2055 * If P_SIGSUSPEND is still set here, then we still need to restore 2056 * the original sigmask before returning to userspace. Also, this 2057 * might unmask some pending signals, so we need to check a second 2058 * time for signals to post. 2059 */ 2060 if (p->p_flag & P_SIGSUSPEND) { 2061 p->p_sigmask = p->p_oldmask; 2062 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2063 2064 while ((signum = cursig(p, &ctx)) != 0) 2065 postsig(p, signum, &ctx); 2066 } 2067 2068 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2069 2070 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2071 } 2072 2073 int 2074 single_thread_check_locked(struct proc *p, int deep) 2075 { 2076 struct process *pr = p->p_p; 2077 2078 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 2079 2080 if (pr->ps_single == NULL || pr->ps_single == p) 2081 return (0); 2082 2083 do { 2084 /* if we're in deep, we need to unwind to the edge */ 2085 if (deep) { 2086 if (pr->ps_flags & PS_SINGLEUNWIND) 2087 return (ERESTART); 2088 if (pr->ps_flags & PS_SINGLEEXIT) 2089 return (EINTR); 2090 } 2091 2092 if (pr->ps_flags & PS_SINGLEEXIT) { 2093 mtx_leave(&pr->ps_mtx); 2094 KERNEL_LOCK(); 2095 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2096 /* NOTREACHED */ 2097 } 2098 2099 if (--pr->ps_singlecnt == 0) 2100 wakeup(&pr->ps_singlecnt); 2101 2102 /* not exiting and don't need to unwind, so suspend */ 2103 mtx_leave(&pr->ps_mtx); 2104 2105 SCHED_LOCK(); 2106 p->p_stat = SSTOP; 2107 mi_switch(); 2108 SCHED_UNLOCK(); 2109 mtx_enter(&pr->ps_mtx); 2110 } while (pr->ps_single != NULL); 2111 2112 return (0); 2113 } 2114 2115 int 2116 single_thread_check(struct proc *p, int deep) 2117 { 2118 int error; 2119 2120 mtx_enter(&p->p_p->ps_mtx); 2121 error = single_thread_check_locked(p, deep); 2122 mtx_leave(&p->p_p->ps_mtx); 2123 2124 return error; 2125 } 2126 2127 /* 2128 * Stop other threads in the process. The mode controls how and 2129 * where the other threads should stop: 2130 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2131 * single_thread_clear()) 2132 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2133 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2134 * - SINGLE_EXIT: unwind to kernel boundary and exit 2135 */ 2136 int 2137 single_thread_set(struct proc *p, int flags) 2138 { 2139 struct process *pr = p->p_p; 2140 struct proc *q; 2141 int error, mode = flags & SINGLE_MASK; 2142 2143 KASSERT(curproc == p); 2144 2145 mtx_enter(&pr->ps_mtx); 2146 error = single_thread_check_locked(p, flags & SINGLE_DEEP); 2147 if (error) { 2148 mtx_leave(&pr->ps_mtx); 2149 return error; 2150 } 2151 2152 switch (mode) { 2153 case SINGLE_SUSPEND: 2154 break; 2155 case SINGLE_UNWIND: 2156 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2157 break; 2158 case SINGLE_EXIT: 2159 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2160 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2161 break; 2162 #ifdef DIAGNOSTIC 2163 default: 2164 panic("single_thread_mode = %d", mode); 2165 #endif 2166 } 2167 KASSERT((p->p_flag & P_SUSPSINGLE) == 0); 2168 pr->ps_single = p; 2169 pr->ps_singlecnt = pr->ps_threadcnt; 2170 2171 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2172 if (q == p) 2173 continue; 2174 SCHED_LOCK(); 2175 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2176 switch (q->p_stat) { 2177 case SSTOP: 2178 if (mode == SINGLE_EXIT) { 2179 unsleep(q); 2180 setrunnable(q); 2181 } else 2182 --pr->ps_singlecnt; 2183 break; 2184 case SSLEEP: 2185 /* if it's not interruptible, then just have to wait */ 2186 if (q->p_flag & P_SINTR) { 2187 /* merely need to suspend? just stop it */ 2188 if (mode == SINGLE_SUSPEND) { 2189 q->p_stat = SSTOP; 2190 --pr->ps_singlecnt; 2191 break; 2192 } 2193 /* need to unwind or exit, so wake it */ 2194 unsleep(q); 2195 setrunnable(q); 2196 } 2197 break; 2198 case SONPROC: 2199 signotify(q); 2200 break; 2201 case SRUN: 2202 case SIDL: 2203 case SDEAD: 2204 break; 2205 } 2206 SCHED_UNLOCK(); 2207 } 2208 2209 /* count ourselfs out */ 2210 --pr->ps_singlecnt; 2211 mtx_leave(&pr->ps_mtx); 2212 2213 if ((flags & SINGLE_NOWAIT) == 0) 2214 single_thread_wait(pr, 1); 2215 2216 return 0; 2217 } 2218 2219 /* 2220 * Wait for other threads to stop. If recheck is false then the function 2221 * returns non-zero if the caller needs to restart the check else 0 is 2222 * returned. If recheck is true the return value is always 0. 2223 */ 2224 int 2225 single_thread_wait(struct process *pr, int recheck) 2226 { 2227 int wait; 2228 2229 /* wait until they're all suspended */ 2230 mtx_enter(&pr->ps_mtx); 2231 while ((wait = pr->ps_singlecnt > 0)) { 2232 msleep_nsec(&pr->ps_singlecnt, &pr->ps_mtx, PWAIT, "suspend", 2233 INFSLP); 2234 if (!recheck) 2235 break; 2236 } 2237 KASSERT((pr->ps_single->p_flag & P_SUSPSINGLE) == 0); 2238 mtx_leave(&pr->ps_mtx); 2239 2240 return wait; 2241 } 2242 2243 void 2244 single_thread_clear(struct proc *p, int flag) 2245 { 2246 struct process *pr = p->p_p; 2247 struct proc *q; 2248 2249 KASSERT(pr->ps_single == p); 2250 KASSERT(curproc == p); 2251 2252 mtx_enter(&pr->ps_mtx); 2253 pr->ps_single = NULL; 2254 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2255 2256 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2257 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2258 continue; 2259 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2260 2261 /* 2262 * if the thread was only stopped for single threading 2263 * then clearing that either makes it runnable or puts 2264 * it back into some sleep queue 2265 */ 2266 SCHED_LOCK(); 2267 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2268 if (q->p_wchan == NULL) 2269 setrunnable(q); 2270 else { 2271 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2272 q->p_stat = SSLEEP; 2273 } 2274 } 2275 SCHED_UNLOCK(); 2276 } 2277 mtx_leave(&pr->ps_mtx); 2278 } 2279 2280 void 2281 sigio_del(struct sigiolst *rmlist) 2282 { 2283 struct sigio *sigio; 2284 2285 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2286 LIST_REMOVE(sigio, sio_pgsigio); 2287 crfree(sigio->sio_ucred); 2288 free(sigio, M_SIGIO, sizeof(*sigio)); 2289 } 2290 } 2291 2292 void 2293 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2294 { 2295 struct sigio *sigio; 2296 2297 MUTEX_ASSERT_LOCKED(&sigio_lock); 2298 2299 sigio = sir->sir_sigio; 2300 if (sigio != NULL) { 2301 KASSERT(sigio->sio_myref == sir); 2302 sir->sir_sigio = NULL; 2303 2304 if (sigio->sio_pgid > 0) 2305 sigio->sio_proc = NULL; 2306 else 2307 sigio->sio_pgrp = NULL; 2308 LIST_REMOVE(sigio, sio_pgsigio); 2309 2310 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2311 } 2312 } 2313 2314 void 2315 sigio_free(struct sigio_ref *sir) 2316 { 2317 struct sigiolst rmlist; 2318 2319 if (sir->sir_sigio == NULL) 2320 return; 2321 2322 LIST_INIT(&rmlist); 2323 2324 mtx_enter(&sigio_lock); 2325 sigio_unlink(sir, &rmlist); 2326 mtx_leave(&sigio_lock); 2327 2328 sigio_del(&rmlist); 2329 } 2330 2331 void 2332 sigio_freelist(struct sigiolst *sigiolst) 2333 { 2334 struct sigiolst rmlist; 2335 struct sigio *sigio; 2336 2337 if (LIST_EMPTY(sigiolst)) 2338 return; 2339 2340 LIST_INIT(&rmlist); 2341 2342 mtx_enter(&sigio_lock); 2343 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2344 sigio_unlink(sigio->sio_myref, &rmlist); 2345 mtx_leave(&sigio_lock); 2346 2347 sigio_del(&rmlist); 2348 } 2349 2350 int 2351 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2352 { 2353 struct sigiolst rmlist; 2354 struct proc *p = curproc; 2355 struct pgrp *pgrp = NULL; 2356 struct process *pr = NULL; 2357 struct sigio *sigio; 2358 int error; 2359 pid_t pgid = *(int *)data; 2360 2361 if (pgid == 0) { 2362 sigio_free(sir); 2363 return (0); 2364 } 2365 2366 if (cmd == TIOCSPGRP) { 2367 if (pgid < 0) 2368 return (EINVAL); 2369 pgid = -pgid; 2370 } 2371 2372 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2373 sigio->sio_pgid = pgid; 2374 sigio->sio_ucred = crhold(p->p_ucred); 2375 sigio->sio_myref = sir; 2376 2377 LIST_INIT(&rmlist); 2378 2379 /* 2380 * The kernel lock, and not sleeping between prfind()/pgfind() and 2381 * linking of the sigio ensure that the process or process group does 2382 * not disappear unexpectedly. 2383 */ 2384 KERNEL_LOCK(); 2385 mtx_enter(&sigio_lock); 2386 2387 if (pgid > 0) { 2388 pr = prfind(pgid); 2389 if (pr == NULL) { 2390 error = ESRCH; 2391 goto fail; 2392 } 2393 2394 /* 2395 * Policy - Don't allow a process to FSETOWN a process 2396 * in another session. 2397 * 2398 * Remove this test to allow maximum flexibility or 2399 * restrict FSETOWN to the current process or process 2400 * group for maximum safety. 2401 */ 2402 if (pr->ps_session != p->p_p->ps_session) { 2403 error = EPERM; 2404 goto fail; 2405 } 2406 2407 if ((pr->ps_flags & PS_EXITING) != 0) { 2408 error = ESRCH; 2409 goto fail; 2410 } 2411 } else /* if (pgid < 0) */ { 2412 pgrp = pgfind(-pgid); 2413 if (pgrp == NULL) { 2414 error = ESRCH; 2415 goto fail; 2416 } 2417 2418 /* 2419 * Policy - Don't allow a process to FSETOWN a process 2420 * in another session. 2421 * 2422 * Remove this test to allow maximum flexibility or 2423 * restrict FSETOWN to the current process or process 2424 * group for maximum safety. 2425 */ 2426 if (pgrp->pg_session != p->p_p->ps_session) { 2427 error = EPERM; 2428 goto fail; 2429 } 2430 } 2431 2432 if (pgid > 0) { 2433 sigio->sio_proc = pr; 2434 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2435 } else { 2436 sigio->sio_pgrp = pgrp; 2437 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2438 } 2439 2440 sigio_unlink(sir, &rmlist); 2441 sir->sir_sigio = sigio; 2442 2443 mtx_leave(&sigio_lock); 2444 KERNEL_UNLOCK(); 2445 2446 sigio_del(&rmlist); 2447 2448 return (0); 2449 2450 fail: 2451 mtx_leave(&sigio_lock); 2452 KERNEL_UNLOCK(); 2453 2454 crfree(sigio->sio_ucred); 2455 free(sigio, M_SIGIO, sizeof(*sigio)); 2456 2457 return (error); 2458 } 2459 2460 void 2461 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2462 { 2463 struct sigio *sigio; 2464 pid_t pgid = 0; 2465 2466 mtx_enter(&sigio_lock); 2467 sigio = sir->sir_sigio; 2468 if (sigio != NULL) 2469 pgid = sigio->sio_pgid; 2470 mtx_leave(&sigio_lock); 2471 2472 if (cmd == TIOCGPGRP) 2473 pgid = -pgid; 2474 2475 *(int *)data = pgid; 2476 } 2477 2478 void 2479 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2480 { 2481 struct sigiolst rmlist; 2482 struct sigio *newsigio, *sigio; 2483 2484 sigio_free(dst); 2485 2486 if (src->sir_sigio == NULL) 2487 return; 2488 2489 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2490 LIST_INIT(&rmlist); 2491 2492 mtx_enter(&sigio_lock); 2493 2494 sigio = src->sir_sigio; 2495 if (sigio == NULL) { 2496 mtx_leave(&sigio_lock); 2497 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2498 return; 2499 } 2500 2501 newsigio->sio_pgid = sigio->sio_pgid; 2502 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2503 newsigio->sio_myref = dst; 2504 if (newsigio->sio_pgid > 0) { 2505 newsigio->sio_proc = sigio->sio_proc; 2506 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2507 sio_pgsigio); 2508 } else { 2509 newsigio->sio_pgrp = sigio->sio_pgrp; 2510 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2511 sio_pgsigio); 2512 } 2513 2514 sigio_unlink(dst, &rmlist); 2515 dst->sir_sigio = newsigio; 2516 2517 mtx_leave(&sigio_lock); 2518 2519 sigio_del(&rmlist); 2520 } 2521