1 /* $OpenBSD: kern_sig.c,v 1.320 2023/10/06 08:58:13 claudio Exp $ */ 2 /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Theo de Raadt. All rights reserved. 6 * Copyright (c) 1982, 1986, 1989, 1991, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 */ 40 41 #include <sys/param.h> 42 #include <sys/signalvar.h> 43 #include <sys/queue.h> 44 #include <sys/namei.h> 45 #include <sys/vnode.h> 46 #include <sys/event.h> 47 #include <sys/proc.h> 48 #include <sys/systm.h> 49 #include <sys/acct.h> 50 #include <sys/fcntl.h> 51 #include <sys/filedesc.h> 52 #include <sys/wait.h> 53 #include <sys/ktrace.h> 54 #include <sys/stat.h> 55 #include <sys/malloc.h> 56 #include <sys/pool.h> 57 #include <sys/sched.h> 58 #include <sys/user.h> 59 #include <sys/syslog.h> 60 #include <sys/ttycom.h> 61 #include <sys/pledge.h> 62 #include <sys/witness.h> 63 #include <sys/exec_elf.h> 64 65 #include <sys/mount.h> 66 #include <sys/syscallargs.h> 67 68 #include <uvm/uvm_extern.h> 69 #include <machine/tcb.h> 70 71 int nosuidcoredump = 1; 72 73 int filt_sigattach(struct knote *kn); 74 void filt_sigdetach(struct knote *kn); 75 int filt_signal(struct knote *kn, long hint); 76 77 const struct filterops sig_filtops = { 78 .f_flags = 0, 79 .f_attach = filt_sigattach, 80 .f_detach = filt_sigdetach, 81 .f_event = filt_signal, 82 }; 83 84 /* 85 * The array below categorizes the signals and their default actions. 86 */ 87 const int sigprop[NSIG] = { 88 0, /* unused */ 89 SA_KILL, /* SIGHUP */ 90 SA_KILL, /* SIGINT */ 91 SA_KILL|SA_CORE, /* SIGQUIT */ 92 SA_KILL|SA_CORE, /* SIGILL */ 93 SA_KILL|SA_CORE, /* SIGTRAP */ 94 SA_KILL|SA_CORE, /* SIGABRT */ 95 SA_KILL|SA_CORE, /* SIGEMT */ 96 SA_KILL|SA_CORE, /* SIGFPE */ 97 SA_KILL, /* SIGKILL */ 98 SA_KILL|SA_CORE, /* SIGBUS */ 99 SA_KILL|SA_CORE, /* SIGSEGV */ 100 SA_KILL|SA_CORE, /* SIGSYS */ 101 SA_KILL, /* SIGPIPE */ 102 SA_KILL, /* SIGALRM */ 103 SA_KILL, /* SIGTERM */ 104 SA_IGNORE, /* SIGURG */ 105 SA_STOP, /* SIGSTOP */ 106 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 107 SA_IGNORE|SA_CONT, /* SIGCONT */ 108 SA_IGNORE, /* SIGCHLD */ 109 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 110 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 111 SA_IGNORE, /* SIGIO */ 112 SA_KILL, /* SIGXCPU */ 113 SA_KILL, /* SIGXFSZ */ 114 SA_KILL, /* SIGVTALRM */ 115 SA_KILL, /* SIGPROF */ 116 SA_IGNORE, /* SIGWINCH */ 117 SA_IGNORE, /* SIGINFO */ 118 SA_KILL, /* SIGUSR1 */ 119 SA_KILL, /* SIGUSR2 */ 120 SA_IGNORE, /* SIGTHR */ 121 }; 122 123 #define CONTSIGMASK (sigmask(SIGCONT)) 124 #define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 125 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 126 127 void setsigvec(struct proc *, int, struct sigaction *); 128 129 void proc_stop(struct proc *p, int); 130 void proc_stop_sweep(void *); 131 void *proc_stop_si; 132 133 void setsigctx(struct proc *, int, struct sigctx *); 134 void postsig_done(struct proc *, int, sigset_t, int); 135 void postsig(struct proc *, int, struct sigctx *); 136 int cansignal(struct proc *, struct process *, int); 137 138 struct pool sigacts_pool; /* memory pool for sigacts structures */ 139 140 void sigio_del(struct sigiolst *); 141 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 142 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 143 144 /* 145 * Can thread p, send the signal signum to process qr? 146 */ 147 int 148 cansignal(struct proc *p, struct process *qr, int signum) 149 { 150 struct process *pr = p->p_p; 151 struct ucred *uc = p->p_ucred; 152 struct ucred *quc = qr->ps_ucred; 153 154 if (uc->cr_uid == 0) 155 return (1); /* root can always signal */ 156 157 if (pr == qr) 158 return (1); /* process can always signal itself */ 159 160 /* optimization: if the same creds then the tests below will pass */ 161 if (uc == quc) 162 return (1); 163 164 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 165 return (1); /* SIGCONT in session */ 166 167 /* 168 * Using kill(), only certain signals can be sent to setugid 169 * child processes 170 */ 171 if (qr->ps_flags & PS_SUGID) { 172 switch (signum) { 173 case 0: 174 case SIGKILL: 175 case SIGINT: 176 case SIGTERM: 177 case SIGALRM: 178 case SIGSTOP: 179 case SIGTTIN: 180 case SIGTTOU: 181 case SIGTSTP: 182 case SIGHUP: 183 case SIGUSR1: 184 case SIGUSR2: 185 if (uc->cr_ruid == quc->cr_ruid || 186 uc->cr_uid == quc->cr_ruid) 187 return (1); 188 } 189 return (0); 190 } 191 192 if (uc->cr_ruid == quc->cr_ruid || 193 uc->cr_ruid == quc->cr_svuid || 194 uc->cr_uid == quc->cr_ruid || 195 uc->cr_uid == quc->cr_svuid) 196 return (1); 197 return (0); 198 } 199 200 /* 201 * Initialize signal-related data structures. 202 */ 203 void 204 signal_init(void) 205 { 206 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 207 NULL); 208 if (proc_stop_si == NULL) 209 panic("signal_init failed to register softintr"); 210 211 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 212 PR_WAITOK, "sigapl", NULL); 213 } 214 215 /* 216 * Initialize a new sigaltstack structure. 217 */ 218 void 219 sigstkinit(struct sigaltstack *ss) 220 { 221 ss->ss_flags = SS_DISABLE; 222 ss->ss_size = 0; 223 ss->ss_sp = NULL; 224 } 225 226 /* 227 * Create an initial sigacts structure, using the same signal state 228 * as pr. 229 */ 230 struct sigacts * 231 sigactsinit(struct process *pr) 232 { 233 struct sigacts *ps; 234 235 ps = pool_get(&sigacts_pool, PR_WAITOK); 236 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 237 return (ps); 238 } 239 240 /* 241 * Release a sigacts structure. 242 */ 243 void 244 sigactsfree(struct sigacts *ps) 245 { 246 pool_put(&sigacts_pool, ps); 247 } 248 249 int 250 sys_sigaction(struct proc *p, void *v, register_t *retval) 251 { 252 struct sys_sigaction_args /* { 253 syscallarg(int) signum; 254 syscallarg(const struct sigaction *) nsa; 255 syscallarg(struct sigaction *) osa; 256 } */ *uap = v; 257 struct sigaction vec; 258 #ifdef KTRACE 259 struct sigaction ovec; 260 #endif 261 struct sigaction *sa; 262 const struct sigaction *nsa; 263 struct sigaction *osa; 264 struct sigacts *ps = p->p_p->ps_sigacts; 265 int signum; 266 int bit, error; 267 268 signum = SCARG(uap, signum); 269 nsa = SCARG(uap, nsa); 270 osa = SCARG(uap, osa); 271 272 if (signum <= 0 || signum >= NSIG || 273 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 274 return (EINVAL); 275 sa = &vec; 276 if (osa) { 277 mtx_enter(&p->p_p->ps_mtx); 278 sa->sa_handler = ps->ps_sigact[signum]; 279 sa->sa_mask = ps->ps_catchmask[signum]; 280 bit = sigmask(signum); 281 sa->sa_flags = 0; 282 if ((ps->ps_sigonstack & bit) != 0) 283 sa->sa_flags |= SA_ONSTACK; 284 if ((ps->ps_sigintr & bit) == 0) 285 sa->sa_flags |= SA_RESTART; 286 if ((ps->ps_sigreset & bit) != 0) 287 sa->sa_flags |= SA_RESETHAND; 288 if ((ps->ps_siginfo & bit) != 0) 289 sa->sa_flags |= SA_SIGINFO; 290 if (signum == SIGCHLD) { 291 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 292 sa->sa_flags |= SA_NOCLDSTOP; 293 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 294 sa->sa_flags |= SA_NOCLDWAIT; 295 } 296 mtx_leave(&p->p_p->ps_mtx); 297 if ((sa->sa_mask & bit) == 0) 298 sa->sa_flags |= SA_NODEFER; 299 sa->sa_mask &= ~bit; 300 error = copyout(sa, osa, sizeof (vec)); 301 if (error) 302 return (error); 303 #ifdef KTRACE 304 if (KTRPOINT(p, KTR_STRUCT)) 305 ovec = vec; 306 #endif 307 } 308 if (nsa) { 309 error = copyin(nsa, sa, sizeof (vec)); 310 if (error) 311 return (error); 312 #ifdef KTRACE 313 if (KTRPOINT(p, KTR_STRUCT)) 314 ktrsigaction(p, sa); 315 #endif 316 setsigvec(p, signum, sa); 317 } 318 #ifdef KTRACE 319 if (osa && KTRPOINT(p, KTR_STRUCT)) 320 ktrsigaction(p, &ovec); 321 #endif 322 return (0); 323 } 324 325 void 326 setsigvec(struct proc *p, int signum, struct sigaction *sa) 327 { 328 struct sigacts *ps = p->p_p->ps_sigacts; 329 int bit; 330 331 bit = sigmask(signum); 332 333 mtx_enter(&p->p_p->ps_mtx); 334 ps->ps_sigact[signum] = sa->sa_handler; 335 if ((sa->sa_flags & SA_NODEFER) == 0) 336 sa->sa_mask |= sigmask(signum); 337 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 338 if (signum == SIGCHLD) { 339 if (sa->sa_flags & SA_NOCLDSTOP) 340 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 341 else 342 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 343 /* 344 * If the SA_NOCLDWAIT flag is set or the handler 345 * is SIG_IGN we reparent the dying child to PID 1 346 * (init) which will reap the zombie. Because we use 347 * init to do our dirty work we never set SAS_NOCLDWAIT 348 * for PID 1. 349 * XXX exit1 rework means this is unnecessary? 350 */ 351 if (initprocess->ps_sigacts != ps && 352 ((sa->sa_flags & SA_NOCLDWAIT) || 353 sa->sa_handler == SIG_IGN)) 354 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 355 else 356 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 357 } 358 if ((sa->sa_flags & SA_RESETHAND) != 0) 359 ps->ps_sigreset |= bit; 360 else 361 ps->ps_sigreset &= ~bit; 362 if ((sa->sa_flags & SA_SIGINFO) != 0) 363 ps->ps_siginfo |= bit; 364 else 365 ps->ps_siginfo &= ~bit; 366 if ((sa->sa_flags & SA_RESTART) == 0) 367 ps->ps_sigintr |= bit; 368 else 369 ps->ps_sigintr &= ~bit; 370 if ((sa->sa_flags & SA_ONSTACK) != 0) 371 ps->ps_sigonstack |= bit; 372 else 373 ps->ps_sigonstack &= ~bit; 374 /* 375 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 376 * and for signals set to SIG_DFL where the default is to ignore. 377 * However, don't put SIGCONT in ps_sigignore, 378 * as we have to restart the process. 379 */ 380 if (sa->sa_handler == SIG_IGN || 381 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 382 atomic_clearbits_int(&p->p_siglist, bit); 383 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 384 if (signum != SIGCONT) 385 ps->ps_sigignore |= bit; /* easier in psignal */ 386 ps->ps_sigcatch &= ~bit; 387 } else { 388 ps->ps_sigignore &= ~bit; 389 if (sa->sa_handler == SIG_DFL) 390 ps->ps_sigcatch &= ~bit; 391 else 392 ps->ps_sigcatch |= bit; 393 } 394 mtx_leave(&p->p_p->ps_mtx); 395 } 396 397 /* 398 * Initialize signal state for process 0; 399 * set to ignore signals that are ignored by default. 400 */ 401 void 402 siginit(struct sigacts *ps) 403 { 404 int i; 405 406 for (i = 0; i < NSIG; i++) 407 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 408 ps->ps_sigignore |= sigmask(i); 409 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 410 } 411 412 /* 413 * Reset signals for an exec by the specified thread. 414 */ 415 void 416 execsigs(struct proc *p) 417 { 418 struct sigacts *ps; 419 int nc, mask; 420 421 ps = p->p_p->ps_sigacts; 422 mtx_enter(&p->p_p->ps_mtx); 423 424 /* 425 * Reset caught signals. Held signals remain held 426 * through p_sigmask (unless they were caught, 427 * and are now ignored by default). 428 */ 429 while (ps->ps_sigcatch) { 430 nc = ffs((long)ps->ps_sigcatch); 431 mask = sigmask(nc); 432 ps->ps_sigcatch &= ~mask; 433 if (sigprop[nc] & SA_IGNORE) { 434 if (nc != SIGCONT) 435 ps->ps_sigignore |= mask; 436 atomic_clearbits_int(&p->p_siglist, mask); 437 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 438 } 439 ps->ps_sigact[nc] = SIG_DFL; 440 } 441 /* 442 * Reset stack state to the user stack. 443 * Clear set of signals caught on the signal stack. 444 */ 445 sigstkinit(&p->p_sigstk); 446 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 447 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 448 ps->ps_sigact[SIGCHLD] = SIG_DFL; 449 mtx_leave(&p->p_p->ps_mtx); 450 } 451 452 /* 453 * Manipulate signal mask. 454 * Note that we receive new mask, not pointer, 455 * and return old mask as return value; 456 * the library stub does the rest. 457 */ 458 int 459 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 460 { 461 struct sys_sigprocmask_args /* { 462 syscallarg(int) how; 463 syscallarg(sigset_t) mask; 464 } */ *uap = v; 465 int error = 0; 466 sigset_t mask; 467 468 KASSERT(p == curproc); 469 470 *retval = p->p_sigmask; 471 mask = SCARG(uap, mask) &~ sigcantmask; 472 473 switch (SCARG(uap, how)) { 474 case SIG_BLOCK: 475 atomic_setbits_int(&p->p_sigmask, mask); 476 break; 477 case SIG_UNBLOCK: 478 atomic_clearbits_int(&p->p_sigmask, mask); 479 break; 480 case SIG_SETMASK: 481 p->p_sigmask = mask; 482 break; 483 default: 484 error = EINVAL; 485 break; 486 } 487 return (error); 488 } 489 490 int 491 sys_sigpending(struct proc *p, void *v, register_t *retval) 492 { 493 *retval = p->p_siglist | p->p_p->ps_siglist; 494 return (0); 495 } 496 497 /* 498 * Temporarily replace calling proc's signal mask for the duration of a 499 * system call. Original signal mask will be restored by userret(). 500 */ 501 void 502 dosigsuspend(struct proc *p, sigset_t newmask) 503 { 504 KASSERT(p == curproc); 505 506 p->p_oldmask = p->p_sigmask; 507 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 508 p->p_sigmask = newmask; 509 } 510 511 /* 512 * Suspend thread until signal, providing mask to be set 513 * in the meantime. Note nonstandard calling convention: 514 * libc stub passes mask, not pointer, to save a copyin. 515 */ 516 int 517 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 518 { 519 struct sys_sigsuspend_args /* { 520 syscallarg(int) mask; 521 } */ *uap = v; 522 523 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 524 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 525 continue; 526 /* always return EINTR rather than ERESTART... */ 527 return (EINTR); 528 } 529 530 int 531 sigonstack(size_t stack) 532 { 533 const struct sigaltstack *ss = &curproc->p_sigstk; 534 535 return (ss->ss_flags & SS_DISABLE ? 0 : 536 (stack - (size_t)ss->ss_sp < ss->ss_size)); 537 } 538 539 int 540 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 541 { 542 struct sys_sigaltstack_args /* { 543 syscallarg(const struct sigaltstack *) nss; 544 syscallarg(struct sigaltstack *) oss; 545 } */ *uap = v; 546 struct sigaltstack ss; 547 const struct sigaltstack *nss; 548 struct sigaltstack *oss; 549 int onstack = sigonstack(PROC_STACK(p)); 550 int error; 551 552 nss = SCARG(uap, nss); 553 oss = SCARG(uap, oss); 554 555 if (oss != NULL) { 556 ss = p->p_sigstk; 557 if (onstack) 558 ss.ss_flags |= SS_ONSTACK; 559 if ((error = copyout(&ss, oss, sizeof(ss)))) 560 return (error); 561 } 562 if (nss == NULL) 563 return (0); 564 error = copyin(nss, &ss, sizeof(ss)); 565 if (error) 566 return (error); 567 if (onstack) 568 return (EPERM); 569 if (ss.ss_flags & ~SS_DISABLE) 570 return (EINVAL); 571 if (ss.ss_flags & SS_DISABLE) { 572 p->p_sigstk.ss_flags = ss.ss_flags; 573 return (0); 574 } 575 if (ss.ss_size < MINSIGSTKSZ) 576 return (ENOMEM); 577 578 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 579 if (error) 580 return (error); 581 582 p->p_sigstk = ss; 583 return (0); 584 } 585 586 int 587 sys_kill(struct proc *cp, void *v, register_t *retval) 588 { 589 struct sys_kill_args /* { 590 syscallarg(int) pid; 591 syscallarg(int) signum; 592 } */ *uap = v; 593 struct process *pr; 594 int pid = SCARG(uap, pid); 595 int signum = SCARG(uap, signum); 596 int error; 597 int zombie = 0; 598 599 if ((error = pledge_kill(cp, pid)) != 0) 600 return (error); 601 if (((u_int)signum) >= NSIG) 602 return (EINVAL); 603 if (pid > 0) { 604 if ((pr = prfind(pid)) == NULL) { 605 if ((pr = zombiefind(pid)) == NULL) 606 return (ESRCH); 607 else 608 zombie = 1; 609 } 610 if (!cansignal(cp, pr, signum)) 611 return (EPERM); 612 613 /* kill single process */ 614 if (signum && !zombie) 615 prsignal(pr, signum); 616 return (0); 617 } 618 switch (pid) { 619 case -1: /* broadcast signal */ 620 return (killpg1(cp, signum, 0, 1)); 621 case 0: /* signal own process group */ 622 return (killpg1(cp, signum, 0, 0)); 623 default: /* negative explicit process group */ 624 return (killpg1(cp, signum, -pid, 0)); 625 } 626 } 627 628 int 629 sys_thrkill(struct proc *cp, void *v, register_t *retval) 630 { 631 struct sys_thrkill_args /* { 632 syscallarg(pid_t) tid; 633 syscallarg(int) signum; 634 syscallarg(void *) tcb; 635 } */ *uap = v; 636 struct proc *p; 637 int tid = SCARG(uap, tid); 638 int signum = SCARG(uap, signum); 639 void *tcb; 640 641 if (((u_int)signum) >= NSIG) 642 return (EINVAL); 643 644 p = tid ? tfind_user(tid, cp->p_p) : cp; 645 if (p == NULL) 646 return (ESRCH); 647 648 /* optionally require the target thread to have the given tcb addr */ 649 tcb = SCARG(uap, tcb); 650 if (tcb != NULL && tcb != TCB_GET(p)) 651 return (ESRCH); 652 653 if (signum) 654 ptsignal(p, signum, STHREAD); 655 return (0); 656 } 657 658 /* 659 * Common code for kill process group/broadcast kill. 660 * cp is calling process. 661 */ 662 int 663 killpg1(struct proc *cp, int signum, int pgid, int all) 664 { 665 struct process *pr; 666 struct pgrp *pgrp; 667 int nfound = 0; 668 669 if (all) { 670 /* 671 * broadcast 672 */ 673 LIST_FOREACH(pr, &allprocess, ps_list) { 674 if (pr->ps_pid <= 1 || 675 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 676 pr == cp->p_p || !cansignal(cp, pr, signum)) 677 continue; 678 nfound++; 679 if (signum) 680 prsignal(pr, signum); 681 } 682 } else { 683 if (pgid == 0) 684 /* 685 * zero pgid means send to my process group. 686 */ 687 pgrp = cp->p_p->ps_pgrp; 688 else { 689 pgrp = pgfind(pgid); 690 if (pgrp == NULL) 691 return (ESRCH); 692 } 693 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 694 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 695 !cansignal(cp, pr, signum)) 696 continue; 697 nfound++; 698 if (signum) 699 prsignal(pr, signum); 700 } 701 } 702 return (nfound ? 0 : ESRCH); 703 } 704 705 #define CANDELIVER(uid, euid, pr) \ 706 (euid == 0 || \ 707 (uid) == (pr)->ps_ucred->cr_ruid || \ 708 (uid) == (pr)->ps_ucred->cr_svuid || \ 709 (uid) == (pr)->ps_ucred->cr_uid || \ 710 (euid) == (pr)->ps_ucred->cr_ruid || \ 711 (euid) == (pr)->ps_ucred->cr_svuid || \ 712 (euid) == (pr)->ps_ucred->cr_uid) 713 714 #define CANSIGIO(cr, pr) \ 715 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 716 717 /* 718 * Send a signal to a process group. If checktty is 1, 719 * limit to members which have a controlling terminal. 720 */ 721 void 722 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 723 { 724 struct process *pr; 725 726 if (pgrp) 727 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 728 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 729 prsignal(pr, signum); 730 } 731 732 /* 733 * Send a SIGIO or SIGURG signal to a process or process group using stored 734 * credentials rather than those of the current process. 735 */ 736 void 737 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 738 { 739 struct process *pr; 740 struct sigio *sigio; 741 742 if (sir->sir_sigio == NULL) 743 return; 744 745 KERNEL_LOCK(); 746 mtx_enter(&sigio_lock); 747 sigio = sir->sir_sigio; 748 if (sigio == NULL) 749 goto out; 750 if (sigio->sio_pgid > 0) { 751 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 752 prsignal(sigio->sio_proc, sig); 753 } else if (sigio->sio_pgid < 0) { 754 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 755 if (CANSIGIO(sigio->sio_ucred, pr) && 756 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 757 prsignal(pr, sig); 758 } 759 } 760 out: 761 mtx_leave(&sigio_lock); 762 KERNEL_UNLOCK(); 763 } 764 765 /* 766 * Recalculate the signal mask and reset the signal disposition after 767 * usermode frame for delivery is formed. 768 */ 769 void 770 postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 771 { 772 p->p_ru.ru_nsignals++; 773 atomic_setbits_int(&p->p_sigmask, catchmask); 774 if (reset != 0) { 775 sigset_t mask = sigmask(signum); 776 struct sigacts *ps = p->p_p->ps_sigacts; 777 778 mtx_enter(&p->p_p->ps_mtx); 779 ps->ps_sigcatch &= ~mask; 780 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 781 ps->ps_sigignore |= mask; 782 ps->ps_sigact[signum] = SIG_DFL; 783 mtx_leave(&p->p_p->ps_mtx); 784 } 785 } 786 787 /* 788 * Send a signal caused by a trap to the current thread 789 * If it will be caught immediately, deliver it with correct code. 790 * Otherwise, post it normally. 791 */ 792 void 793 trapsignal(struct proc *p, int signum, u_long trapno, int code, 794 union sigval sigval) 795 { 796 struct process *pr = p->p_p; 797 struct sigctx ctx; 798 int mask; 799 800 switch (signum) { 801 case SIGILL: 802 case SIGBUS: 803 case SIGSEGV: 804 pr->ps_acflag |= ATRAP; 805 break; 806 } 807 808 mask = sigmask(signum); 809 setsigctx(p, signum, &ctx); 810 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 811 (p->p_sigmask & mask) == 0) { 812 siginfo_t si; 813 814 initsiginfo(&si, signum, trapno, code, sigval); 815 #ifdef KTRACE 816 if (KTRPOINT(p, KTR_PSIG)) { 817 ktrpsig(p, signum, ctx.sig_action, 818 p->p_sigmask, code, &si); 819 } 820 #endif 821 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 822 ctx.sig_info, ctx.sig_onstack)) { 823 KERNEL_LOCK(); 824 sigexit(p, SIGILL); 825 /* NOTREACHED */ 826 } 827 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 828 } else { 829 p->p_sisig = signum; 830 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 831 p->p_sicode = code; 832 p->p_sigval = sigval; 833 834 /* 835 * If traced, stop if signal is masked, and stay stopped 836 * until released by the debugger. If our parent process 837 * is waiting for us, don't hang as we could deadlock. 838 */ 839 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 840 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 841 int s; 842 843 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 844 pr->ps_xsig = signum; 845 846 SCHED_LOCK(s); 847 proc_stop(p, 1); 848 SCHED_UNLOCK(s); 849 850 signum = pr->ps_xsig; 851 single_thread_clear(p, 0); 852 853 /* 854 * If we are no longer being traced, or the parent 855 * didn't give us a signal, skip sending the signal. 856 */ 857 if ((pr->ps_flags & PS_TRACED) == 0 || 858 signum == 0) 859 return; 860 861 /* update signal info */ 862 p->p_sisig = signum; 863 mask = sigmask(signum); 864 } 865 866 /* 867 * Signals like SIGBUS and SIGSEGV should not, when 868 * generated by the kernel, be ignorable or blockable. 869 * If it is and we're not being traced, then just kill 870 * the process. 871 * After vfs_shutdown(9), init(8) cannot receive signals 872 * because new code pages of the signal handler cannot be 873 * mapped from halted storage. init(8) may not die or the 874 * kernel panics. Better loop between signal handler and 875 * page fault trap until the machine is halted. 876 */ 877 if ((pr->ps_flags & PS_TRACED) == 0 && 878 (sigprop[signum] & SA_KILL) && 879 ((p->p_sigmask & mask) || ctx.sig_ignore) && 880 pr->ps_pid != 1) { 881 KERNEL_LOCK(); 882 sigexit(p, signum); 883 /* NOTREACHED */ 884 } 885 KERNEL_LOCK(); 886 ptsignal(p, signum, STHREAD); 887 KERNEL_UNLOCK(); 888 } 889 } 890 891 /* 892 * Send the signal to the process. If the signal has an action, the action 893 * is usually performed by the target process rather than the caller; we add 894 * the signal to the set of pending signals for the process. 895 * 896 * Exceptions: 897 * o When a stop signal is sent to a sleeping process that takes the 898 * default action, the process is stopped without awakening it. 899 * o SIGCONT restarts stopped processes (or puts them back to sleep) 900 * regardless of the signal action (eg, blocked or ignored). 901 * 902 * Other ignored signals are discarded immediately. 903 */ 904 void 905 psignal(struct proc *p, int signum) 906 { 907 ptsignal(p, signum, SPROCESS); 908 } 909 910 /* 911 * type = SPROCESS process signal, can be diverted (sigwait()) 912 * type = STHREAD thread signal, but should be propagated if unhandled 913 * type = SPROPAGATED propagated to this thread, so don't propagate again 914 */ 915 void 916 ptsignal(struct proc *p, int signum, enum signal_type type) 917 { 918 int s, prop; 919 sig_t action; 920 int mask; 921 int *siglist; 922 struct process *pr = p->p_p; 923 struct proc *q; 924 int wakeparent = 0; 925 926 KERNEL_ASSERT_LOCKED(); 927 928 #ifdef DIAGNOSTIC 929 if ((u_int)signum >= NSIG || signum == 0) 930 panic("psignal signal number"); 931 #endif 932 933 /* Ignore signal if the target process is exiting */ 934 if (pr->ps_flags & PS_EXITING) 935 return; 936 937 mask = sigmask(signum); 938 939 if (type == SPROCESS) { 940 /* Accept SIGKILL to coredumping processes */ 941 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 942 atomic_setbits_int(&pr->ps_siglist, mask); 943 return; 944 } 945 946 /* 947 * If the current thread can process the signal 948 * immediately (it's unblocked) then have it take it. 949 */ 950 q = curproc; 951 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 952 (q->p_sigmask & mask) == 0) 953 p = q; 954 else { 955 /* 956 * A process-wide signal can be diverted to a 957 * different thread that's in sigwait() for this 958 * signal. If there isn't such a thread, then 959 * pick a thread that doesn't have it blocked so 960 * that the stop/kill consideration isn't 961 * delayed. Otherwise, mark it pending on the 962 * main thread. 963 */ 964 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 965 /* ignore exiting threads */ 966 if (q->p_flag & P_WEXIT) 967 continue; 968 969 /* skip threads that have the signal blocked */ 970 if ((q->p_sigmask & mask) != 0) 971 continue; 972 973 /* okay, could send to this thread */ 974 p = q; 975 976 /* 977 * sigsuspend, sigwait, ppoll/pselect, etc? 978 * Definitely go to this thread, as it's 979 * already blocked in the kernel. 980 */ 981 if (q->p_flag & P_SIGSUSPEND) 982 break; 983 } 984 } 985 } 986 987 if (type != SPROPAGATED) 988 knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); 989 990 prop = sigprop[signum]; 991 992 /* 993 * If proc is traced, always give parent a chance. 994 */ 995 if (pr->ps_flags & PS_TRACED) { 996 action = SIG_DFL; 997 } else { 998 sigset_t sigcatch, sigignore; 999 1000 /* 1001 * If the signal is being ignored, 1002 * then we forget about it immediately. 1003 * (Note: we don't set SIGCONT in ps_sigignore, 1004 * and if it is set to SIG_IGN, 1005 * action will be SIG_DFL here.) 1006 */ 1007 mtx_enter(&pr->ps_mtx); 1008 sigignore = pr->ps_sigacts->ps_sigignore; 1009 sigcatch = pr->ps_sigacts->ps_sigcatch; 1010 mtx_leave(&pr->ps_mtx); 1011 1012 if (sigignore & mask) 1013 return; 1014 if (p->p_sigmask & mask) { 1015 action = SIG_HOLD; 1016 } else if (sigcatch & mask) { 1017 action = SIG_CATCH; 1018 } else { 1019 action = SIG_DFL; 1020 1021 if (prop & SA_KILL && pr->ps_nice > NZERO) 1022 pr->ps_nice = NZERO; 1023 1024 /* 1025 * If sending a tty stop signal to a member of an 1026 * orphaned process group, discard the signal here if 1027 * the action is default; don't stop the process below 1028 * if sleeping, and don't clear any pending SIGCONT. 1029 */ 1030 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1031 return; 1032 } 1033 } 1034 /* 1035 * If delivered to process, mark as pending there. Continue and stop 1036 * signals will be propagated to all threads. So they are always 1037 * marked at thread level. 1038 */ 1039 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1040 if (prop & SA_CONT) { 1041 siglist = &p->p_siglist; 1042 atomic_clearbits_int(siglist, STOPSIGMASK); 1043 } 1044 if (prop & SA_STOP) { 1045 siglist = &p->p_siglist; 1046 atomic_clearbits_int(siglist, CONTSIGMASK); 1047 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1048 } 1049 1050 /* 1051 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1052 */ 1053 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1054 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1055 if (q != p) 1056 ptsignal(q, signum, SPROPAGATED); 1057 1058 /* 1059 * Defer further processing for signals which are held, 1060 * except that stopped processes must be continued by SIGCONT. 1061 */ 1062 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || 1063 p->p_stat != SSTOP)) { 1064 atomic_setbits_int(siglist, mask); 1065 return; 1066 } 1067 1068 SCHED_LOCK(s); 1069 1070 switch (p->p_stat) { 1071 1072 case SSLEEP: 1073 /* 1074 * If process is sleeping uninterruptibly 1075 * we can't interrupt the sleep... the signal will 1076 * be noticed when the process returns through 1077 * trap() or syscall(). 1078 */ 1079 if ((p->p_flag & P_SINTR) == 0) 1080 goto out; 1081 /* 1082 * Process is sleeping and traced... make it runnable 1083 * so it can discover the signal in cursig() and stop 1084 * for the parent. 1085 */ 1086 if (pr->ps_flags & PS_TRACED) 1087 goto run; 1088 /* 1089 * If SIGCONT is default (or ignored) and process is 1090 * asleep, we are finished; the process should not 1091 * be awakened. 1092 */ 1093 if ((prop & SA_CONT) && action == SIG_DFL) { 1094 mask = 0; 1095 goto out; 1096 } 1097 /* 1098 * When a sleeping process receives a stop 1099 * signal, process immediately if possible. 1100 */ 1101 if ((prop & SA_STOP) && action == SIG_DFL) { 1102 /* 1103 * If a child holding parent blocked, 1104 * stopping could cause deadlock. 1105 */ 1106 if (pr->ps_flags & PS_PPWAIT) 1107 goto out; 1108 mask = 0; 1109 pr->ps_xsig = signum; 1110 proc_stop(p, 0); 1111 goto out; 1112 } 1113 /* 1114 * All other (caught or default) signals 1115 * cause the process to run. 1116 */ 1117 goto runfast; 1118 /* NOTREACHED */ 1119 1120 case SSTOP: 1121 /* 1122 * If traced process is already stopped, 1123 * then no further action is necessary. 1124 */ 1125 if (pr->ps_flags & PS_TRACED) 1126 goto out; 1127 1128 /* 1129 * Kill signal always sets processes running. 1130 */ 1131 if (signum == SIGKILL) { 1132 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1133 goto runfast; 1134 } 1135 1136 if (prop & SA_CONT) { 1137 /* 1138 * If SIGCONT is default (or ignored), we continue the 1139 * process but don't leave the signal in p_siglist, as 1140 * it has no further action. If SIGCONT is held, we 1141 * continue the process and leave the signal in 1142 * p_siglist. If the process catches SIGCONT, let it 1143 * handle the signal itself. If it isn't waiting on 1144 * an event, then it goes back to run state. 1145 * Otherwise, process goes back to sleep state. 1146 */ 1147 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1148 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1149 wakeparent = 1; 1150 if (action == SIG_DFL) 1151 atomic_clearbits_int(siglist, mask); 1152 if (action == SIG_CATCH) 1153 goto runfast; 1154 if (p->p_wchan == NULL) 1155 goto run; 1156 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1157 p->p_stat = SSLEEP; 1158 goto out; 1159 } 1160 1161 if (prop & SA_STOP) { 1162 /* 1163 * Already stopped, don't need to stop again. 1164 * (If we did the shell could get confused.) 1165 */ 1166 mask = 0; 1167 goto out; 1168 } 1169 1170 /* 1171 * If process is sleeping interruptibly, then simulate a 1172 * wakeup so that when it is continued, it will be made 1173 * runnable and can look at the signal. But don't make 1174 * the process runnable, leave it stopped. 1175 */ 1176 if (p->p_flag & P_SINTR) 1177 unsleep(p); 1178 goto out; 1179 1180 case SONPROC: 1181 /* set siglist before issuing the ast */ 1182 atomic_setbits_int(siglist, mask); 1183 mask = 0; 1184 signotify(p); 1185 /* FALLTHROUGH */ 1186 default: 1187 /* 1188 * SRUN, SIDL, SDEAD do nothing with the signal, 1189 * other than kicking ourselves if we are running. 1190 * It will either never be noticed, or noticed very soon. 1191 */ 1192 goto out; 1193 } 1194 /* NOTREACHED */ 1195 1196 runfast: 1197 /* 1198 * Raise priority to at least PUSER. 1199 */ 1200 if (p->p_usrpri > PUSER) 1201 p->p_usrpri = PUSER; 1202 run: 1203 setrunnable(p); 1204 out: 1205 /* finally adjust siglist */ 1206 if (mask) 1207 atomic_setbits_int(siglist, mask); 1208 SCHED_UNLOCK(s); 1209 if (wakeparent) 1210 wakeup(pr->ps_pptr); 1211 } 1212 1213 /* fill the signal context which should be used by postsig() and issignal() */ 1214 void 1215 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1216 { 1217 struct sigacts *ps = p->p_p->ps_sigacts; 1218 sigset_t mask; 1219 1220 mtx_enter(&p->p_p->ps_mtx); 1221 mask = sigmask(signum); 1222 sctx->sig_action = ps->ps_sigact[signum]; 1223 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1224 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1225 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1226 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1227 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1228 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1229 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1230 mtx_leave(&p->p_p->ps_mtx); 1231 } 1232 1233 /* 1234 * Determine signal that should be delivered to process p, the current 1235 * process, 0 if none. 1236 * 1237 * If the current process has received a signal (should be caught or cause 1238 * termination, should interrupt current syscall), return the signal number. 1239 * Stop signals with default action are processed immediately, then cleared; 1240 * they aren't returned. This is checked after each entry to the system for 1241 * a syscall or trap. The normal call sequence is 1242 * 1243 * while (signum = cursig(curproc, &ctx)) 1244 * postsig(signum, &ctx); 1245 * 1246 * Assumes that if the P_SINTR flag is set, we're holding both the 1247 * kernel and scheduler locks. 1248 */ 1249 int 1250 cursig(struct proc *p, struct sigctx *sctx) 1251 { 1252 struct process *pr = p->p_p; 1253 int signum, mask, prop; 1254 sigset_t ps_siglist; 1255 int s; 1256 1257 KASSERT(p == curproc); 1258 1259 for (;;) { 1260 ps_siglist = READ_ONCE(pr->ps_siglist); 1261 membar_consumer(); 1262 mask = SIGPENDING(p); 1263 if (pr->ps_flags & PS_PPWAIT) 1264 mask &= ~STOPSIGMASK; 1265 if (mask == 0) /* no signal to send */ 1266 return (0); 1267 signum = ffs((long)mask); 1268 mask = sigmask(signum); 1269 1270 /* take the signal! */ 1271 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1272 ps_siglist & ~mask) != ps_siglist) { 1273 /* lost race taking the process signal, restart */ 1274 continue; 1275 } 1276 atomic_clearbits_int(&p->p_siglist, mask); 1277 setsigctx(p, signum, sctx); 1278 1279 /* 1280 * We should see pending but ignored signals 1281 * only if PS_TRACED was on when they were posted. 1282 */ 1283 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1284 continue; 1285 1286 /* 1287 * If traced, always stop, and stay stopped until released 1288 * by the debugger. If our parent process is waiting for 1289 * us, don't hang as we could deadlock. 1290 */ 1291 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1292 signum != SIGKILL) { 1293 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1294 pr->ps_xsig = signum; 1295 1296 SCHED_LOCK(s); 1297 proc_stop(p, 1); 1298 SCHED_UNLOCK(s); 1299 1300 /* 1301 * re-take the signal before releasing 1302 * the other threads. Must check the continue 1303 * conditions below and only take the signal if 1304 * those are not true. 1305 */ 1306 signum = pr->ps_xsig; 1307 mask = sigmask(signum); 1308 setsigctx(p, signum, sctx); 1309 if (!((pr->ps_flags & PS_TRACED) == 0 || 1310 signum == 0 || 1311 (p->p_sigmask & mask) != 0)) { 1312 atomic_clearbits_int(&p->p_siglist, mask); 1313 atomic_clearbits_int(&pr->ps_siglist, mask); 1314 } 1315 1316 single_thread_clear(p, 0); 1317 1318 /* 1319 * If we are no longer being traced, or the parent 1320 * didn't give us a signal, look for more signals. 1321 */ 1322 if ((pr->ps_flags & PS_TRACED) == 0 || 1323 signum == 0) 1324 continue; 1325 1326 /* 1327 * If the new signal is being masked, look for other 1328 * signals. 1329 */ 1330 if ((p->p_sigmask & mask) != 0) 1331 continue; 1332 1333 } 1334 1335 prop = sigprop[signum]; 1336 1337 /* 1338 * Decide whether the signal should be returned. 1339 * Return the signal's number, or fall through 1340 * to clear it from the pending mask. 1341 */ 1342 switch ((long)sctx->sig_action) { 1343 case (long)SIG_DFL: 1344 /* 1345 * Don't take default actions on system processes. 1346 */ 1347 if (pr->ps_pid <= 1) { 1348 #ifdef DIAGNOSTIC 1349 /* 1350 * Are you sure you want to ignore SIGSEGV 1351 * in init? XXX 1352 */ 1353 printf("Process (pid %d) got signal" 1354 " %d\n", pr->ps_pid, signum); 1355 #endif 1356 break; /* == ignore */ 1357 } 1358 /* 1359 * If there is a pending stop signal to process 1360 * with default action, stop here, 1361 * then clear the signal. However, 1362 * if process is member of an orphaned 1363 * process group, ignore tty stop signals. 1364 */ 1365 if (prop & SA_STOP) { 1366 if (pr->ps_flags & PS_TRACED || 1367 (pr->ps_pgrp->pg_jobc == 0 && 1368 prop & SA_TTYSTOP)) 1369 break; /* == ignore */ 1370 pr->ps_xsig = signum; 1371 SCHED_LOCK(s); 1372 proc_stop(p, 1); 1373 SCHED_UNLOCK(s); 1374 break; 1375 } else if (prop & SA_IGNORE) { 1376 /* 1377 * Except for SIGCONT, shouldn't get here. 1378 * Default action is to ignore; drop it. 1379 */ 1380 break; /* == ignore */ 1381 } else 1382 goto keep; 1383 /* NOTREACHED */ 1384 case (long)SIG_IGN: 1385 /* 1386 * Masking above should prevent us ever trying 1387 * to take action on an ignored signal other 1388 * than SIGCONT, unless process is traced. 1389 */ 1390 if ((prop & SA_CONT) == 0 && 1391 (pr->ps_flags & PS_TRACED) == 0) 1392 printf("%s\n", __func__); 1393 break; /* == ignore */ 1394 default: 1395 /* 1396 * This signal has an action, let 1397 * postsig() process it. 1398 */ 1399 goto keep; 1400 } 1401 } 1402 /* NOTREACHED */ 1403 1404 keep: 1405 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1406 return (signum); 1407 } 1408 1409 /* 1410 * Put the argument process into the stopped state and notify the parent 1411 * via wakeup. Signals are handled elsewhere. The process must not be 1412 * on the run queue. 1413 */ 1414 void 1415 proc_stop(struct proc *p, int sw) 1416 { 1417 struct process *pr = p->p_p; 1418 1419 #ifdef MULTIPROCESSOR 1420 SCHED_ASSERT_LOCKED(); 1421 #endif 1422 1423 p->p_stat = SSTOP; 1424 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1425 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1426 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1427 /* 1428 * We need this soft interrupt to be handled fast. 1429 * Extra calls to softclock don't hurt. 1430 */ 1431 softintr_schedule(proc_stop_si); 1432 if (sw) 1433 mi_switch(); 1434 } 1435 1436 /* 1437 * Called from a soft interrupt to send signals to the parents of stopped 1438 * processes. 1439 * We can't do this in proc_stop because it's called with nasty locks held 1440 * and we would need recursive scheduler lock to deal with that. 1441 */ 1442 void 1443 proc_stop_sweep(void *v) 1444 { 1445 struct process *pr; 1446 1447 LIST_FOREACH(pr, &allprocess, ps_list) { 1448 if ((pr->ps_flags & PS_STOPPED) == 0) 1449 continue; 1450 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1451 1452 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1453 prsignal(pr->ps_pptr, SIGCHLD); 1454 wakeup(pr->ps_pptr); 1455 } 1456 } 1457 1458 /* 1459 * Take the action for the specified signal 1460 * from the current set of pending signals. 1461 */ 1462 void 1463 postsig(struct proc *p, int signum, struct sigctx *sctx) 1464 { 1465 u_long trapno; 1466 int mask, returnmask; 1467 siginfo_t si; 1468 union sigval sigval; 1469 int code; 1470 1471 KASSERT(signum != 0); 1472 1473 mask = sigmask(signum); 1474 atomic_clearbits_int(&p->p_siglist, mask); 1475 sigval.sival_ptr = NULL; 1476 1477 if (p->p_sisig != signum) { 1478 trapno = 0; 1479 code = SI_USER; 1480 sigval.sival_ptr = NULL; 1481 } else { 1482 trapno = p->p_sitrapno; 1483 code = p->p_sicode; 1484 sigval = p->p_sigval; 1485 } 1486 initsiginfo(&si, signum, trapno, code, sigval); 1487 1488 #ifdef KTRACE 1489 if (KTRPOINT(p, KTR_PSIG)) { 1490 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1491 p->p_oldmask : p->p_sigmask, code, &si); 1492 } 1493 #endif 1494 if (sctx->sig_action == SIG_DFL) { 1495 /* 1496 * Default action, where the default is to kill 1497 * the process. (Other cases were ignored above.) 1498 */ 1499 KERNEL_LOCK(); 1500 sigexit(p, signum); 1501 /* NOTREACHED */ 1502 } else { 1503 /* 1504 * If we get here, the signal must be caught. 1505 */ 1506 #ifdef DIAGNOSTIC 1507 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1508 panic("postsig action"); 1509 #endif 1510 /* 1511 * Set the new mask value and also defer further 1512 * occurrences of this signal. 1513 * 1514 * Special case: user has done a sigpause. Here the 1515 * current mask is not of interest, but rather the 1516 * mask from before the sigpause is what we want 1517 * restored after the signal processing is completed. 1518 */ 1519 if (p->p_flag & P_SIGSUSPEND) { 1520 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1521 returnmask = p->p_oldmask; 1522 } else { 1523 returnmask = p->p_sigmask; 1524 } 1525 if (p->p_sisig == signum) { 1526 p->p_sisig = 0; 1527 p->p_sitrapno = 0; 1528 p->p_sicode = SI_USER; 1529 p->p_sigval.sival_ptr = NULL; 1530 } 1531 1532 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1533 sctx->sig_info, sctx->sig_onstack)) { 1534 KERNEL_LOCK(); 1535 sigexit(p, SIGILL); 1536 /* NOTREACHED */ 1537 } 1538 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1539 } 1540 } 1541 1542 /* 1543 * Force the current process to exit with the specified signal, dumping core 1544 * if appropriate. We bypass the normal tests for masked and caught signals, 1545 * allowing unrecoverable failures to terminate the process without changing 1546 * signal state. Mark the accounting record with the signal termination. 1547 * If dumping core, save the signal number for the debugger. Calls exit and 1548 * does not return. 1549 */ 1550 void 1551 sigexit(struct proc *p, int signum) 1552 { 1553 /* Mark process as going away */ 1554 atomic_setbits_int(&p->p_flag, P_WEXIT); 1555 1556 p->p_p->ps_acflag |= AXSIG; 1557 if (sigprop[signum] & SA_CORE) { 1558 p->p_sisig = signum; 1559 1560 /* if there are other threads, pause them */ 1561 if (P_HASSIBLING(p)) 1562 single_thread_set(p, SINGLE_UNWIND); 1563 1564 if (coredump(p) == 0) 1565 signum |= WCOREFLAG; 1566 } 1567 exit1(p, 0, signum, EXIT_NORMAL); 1568 /* NOTREACHED */ 1569 } 1570 1571 /* 1572 * Send uncatchable SIGABRT for coredump. 1573 */ 1574 void 1575 sigabort(struct proc *p) 1576 { 1577 struct sigaction sa; 1578 1579 memset(&sa, 0, sizeof sa); 1580 sa.sa_handler = SIG_DFL; 1581 setsigvec(p, SIGABRT, &sa); 1582 atomic_clearbits_int(&p->p_sigmask, sigmask(SIGABRT)); 1583 psignal(p, SIGABRT); 1584 } 1585 1586 /* 1587 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1588 * thread, and 0 otherwise. 1589 */ 1590 int 1591 sigismasked(struct proc *p, int sig) 1592 { 1593 struct process *pr = p->p_p; 1594 int rv; 1595 1596 mtx_enter(&pr->ps_mtx); 1597 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1598 (p->p_sigmask & sigmask(sig)); 1599 mtx_leave(&pr->ps_mtx); 1600 1601 return !!rv; 1602 } 1603 1604 struct coredump_iostate { 1605 struct proc *io_proc; 1606 struct vnode *io_vp; 1607 struct ucred *io_cred; 1608 off_t io_offset; 1609 }; 1610 1611 /* 1612 * Dump core, into a file named "progname.core", unless the process was 1613 * setuid/setgid. 1614 */ 1615 int 1616 coredump(struct proc *p) 1617 { 1618 #ifdef SMALL_KERNEL 1619 return EPERM; 1620 #else 1621 struct process *pr = p->p_p; 1622 struct vnode *vp; 1623 struct ucred *cred = p->p_ucred; 1624 struct vmspace *vm = p->p_vmspace; 1625 struct nameidata nd; 1626 struct vattr vattr; 1627 struct coredump_iostate io; 1628 int error, len, incrash = 0; 1629 char *name; 1630 const char *dir = "/var/crash"; 1631 1632 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1633 1634 #ifdef PMAP_CHECK_COPYIN 1635 /* disable copyin checks, so we can write out text sections if needed */ 1636 p->p_vmspace->vm_map.check_copyin_count = 0; 1637 #endif 1638 1639 /* Don't dump if will exceed file size limit. */ 1640 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1641 return (EFBIG); 1642 1643 name = pool_get(&namei_pool, PR_WAITOK); 1644 1645 /* 1646 * If the process has inconsistent uids, nosuidcoredump 1647 * determines coredump placement policy. 1648 */ 1649 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1650 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1651 if (nosuidcoredump == 3) { 1652 /* 1653 * If the program directory does not exist, dumps of 1654 * that core will silently fail. 1655 */ 1656 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1657 dir, pr->ps_comm, pr->ps_pid); 1658 incrash = KERNELPATH; 1659 } else if (nosuidcoredump == 2) { 1660 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1661 dir, pr->ps_comm); 1662 incrash = KERNELPATH; 1663 } else { 1664 pool_put(&namei_pool, name); 1665 return (EPERM); 1666 } 1667 } else 1668 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1669 1670 if (len >= MAXPATHLEN) { 1671 pool_put(&namei_pool, name); 1672 return (EACCES); 1673 } 1674 1675 /* 1676 * Control the UID used to write out. The normal case uses 1677 * the real UID. If the sugid case is going to write into the 1678 * controlled directory, we do so as root. 1679 */ 1680 if (incrash == 0) { 1681 cred = crdup(cred); 1682 cred->cr_uid = cred->cr_ruid; 1683 cred->cr_gid = cred->cr_rgid; 1684 } else { 1685 if (p->p_fd->fd_rdir) { 1686 vrele(p->p_fd->fd_rdir); 1687 p->p_fd->fd_rdir = NULL; 1688 } 1689 p->p_ucred = crdup(p->p_ucred); 1690 crfree(cred); 1691 cred = p->p_ucred; 1692 crhold(cred); 1693 cred->cr_uid = 0; 1694 cred->cr_gid = 0; 1695 } 1696 1697 /* incrash should be 0 or KERNELPATH only */ 1698 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1699 1700 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1701 S_IRUSR | S_IWUSR); 1702 1703 if (error) 1704 goto out; 1705 1706 /* 1707 * Don't dump to non-regular files, files with links, or files 1708 * owned by someone else. 1709 */ 1710 vp = nd.ni_vp; 1711 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1712 VOP_UNLOCK(vp); 1713 vn_close(vp, FWRITE, cred, p); 1714 goto out; 1715 } 1716 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1717 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1718 vattr.va_uid != cred->cr_uid) { 1719 error = EACCES; 1720 VOP_UNLOCK(vp); 1721 vn_close(vp, FWRITE, cred, p); 1722 goto out; 1723 } 1724 VATTR_NULL(&vattr); 1725 vattr.va_size = 0; 1726 VOP_SETATTR(vp, &vattr, cred, p); 1727 pr->ps_acflag |= ACORE; 1728 1729 io.io_proc = p; 1730 io.io_vp = vp; 1731 io.io_cred = cred; 1732 io.io_offset = 0; 1733 VOP_UNLOCK(vp); 1734 vref(vp); 1735 error = vn_close(vp, FWRITE, cred, p); 1736 if (error == 0) 1737 error = coredump_elf(p, &io); 1738 vrele(vp); 1739 out: 1740 crfree(cred); 1741 pool_put(&namei_pool, name); 1742 return (error); 1743 #endif 1744 } 1745 1746 #ifndef SMALL_KERNEL 1747 int 1748 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1749 { 1750 struct coredump_iostate *io = cookie; 1751 off_t coffset = 0; 1752 size_t csize; 1753 int chunk, error; 1754 1755 csize = len; 1756 do { 1757 if (sigmask(SIGKILL) & 1758 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1759 return (EINTR); 1760 1761 /* Rest of the loop sleeps with lock held, so... */ 1762 yield(); 1763 1764 chunk = MIN(csize, MAXPHYS); 1765 error = vn_rdwr(UIO_WRITE, io->io_vp, 1766 (caddr_t)data + coffset, chunk, 1767 io->io_offset + coffset, segflg, 1768 IO_UNIT, io->io_cred, NULL, io->io_proc); 1769 if (error) { 1770 struct process *pr = io->io_proc->p_p; 1771 1772 if (error == ENOSPC) 1773 log(LOG_ERR, 1774 "coredump of %s(%d) failed, filesystem full\n", 1775 pr->ps_comm, pr->ps_pid); 1776 else 1777 log(LOG_ERR, 1778 "coredump of %s(%d), write failed: errno %d\n", 1779 pr->ps_comm, pr->ps_pid, error); 1780 return (error); 1781 } 1782 1783 coffset += chunk; 1784 csize -= chunk; 1785 } while (csize > 0); 1786 1787 io->io_offset += len; 1788 return (0); 1789 } 1790 1791 void 1792 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1793 { 1794 struct coredump_iostate *io = cookie; 1795 1796 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1797 } 1798 1799 #endif /* !SMALL_KERNEL */ 1800 1801 /* 1802 * Nonexistent system call-- signal process (may want to handle it). 1803 * Flag error in case process won't see signal immediately (blocked or ignored). 1804 */ 1805 int 1806 sys_nosys(struct proc *p, void *v, register_t *retval) 1807 { 1808 ptsignal(p, SIGSYS, STHREAD); 1809 return (ENOSYS); 1810 } 1811 1812 int 1813 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1814 { 1815 struct sys___thrsigdivert_args /* { 1816 syscallarg(sigset_t) sigmask; 1817 syscallarg(siginfo_t *) info; 1818 syscallarg(const struct timespec *) timeout; 1819 } */ *uap = v; 1820 struct sigctx ctx; 1821 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1822 siginfo_t si; 1823 uint64_t nsecs = INFSLP; 1824 int timeinvalid = 0; 1825 int error = 0; 1826 1827 memset(&si, 0, sizeof(si)); 1828 1829 if (SCARG(uap, timeout) != NULL) { 1830 struct timespec ts; 1831 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1832 return (error); 1833 #ifdef KTRACE 1834 if (KTRPOINT(p, KTR_STRUCT)) 1835 ktrreltimespec(p, &ts); 1836 #endif 1837 if (!timespecisvalid(&ts)) 1838 timeinvalid = 1; 1839 else 1840 nsecs = TIMESPEC_TO_NSEC(&ts); 1841 } 1842 1843 dosigsuspend(p, p->p_sigmask &~ mask); 1844 for (;;) { 1845 si.si_signo = cursig(p, &ctx); 1846 if (si.si_signo != 0) { 1847 sigset_t smask = sigmask(si.si_signo); 1848 if (smask & mask) { 1849 atomic_clearbits_int(&p->p_siglist, smask); 1850 error = 0; 1851 break; 1852 } 1853 } 1854 1855 /* per-POSIX, delay this error until after the above */ 1856 if (timeinvalid) 1857 error = EINVAL; 1858 /* per-POSIX, return immediately if timeout is zero-valued */ 1859 if (nsecs == 0) 1860 error = EAGAIN; 1861 1862 if (error != 0) 1863 break; 1864 1865 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1866 } 1867 1868 if (error == 0) { 1869 *retval = si.si_signo; 1870 if (SCARG(uap, info) != NULL) { 1871 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1872 #ifdef KTRACE 1873 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1874 ktrsiginfo(p, &si); 1875 #endif 1876 } 1877 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1878 /* 1879 * Restarting is wrong if there's a timeout, as it'll be 1880 * for the same interval again 1881 */ 1882 error = EINTR; 1883 } 1884 1885 return (error); 1886 } 1887 1888 void 1889 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1890 { 1891 memset(si, 0, sizeof(*si)); 1892 1893 si->si_signo = sig; 1894 si->si_code = code; 1895 if (code == SI_USER) { 1896 si->si_value = val; 1897 } else { 1898 switch (sig) { 1899 case SIGSEGV: 1900 case SIGILL: 1901 case SIGBUS: 1902 case SIGFPE: 1903 si->si_addr = val.sival_ptr; 1904 si->si_trapno = trapno; 1905 break; 1906 case SIGXFSZ: 1907 break; 1908 } 1909 } 1910 } 1911 1912 int 1913 filt_sigattach(struct knote *kn) 1914 { 1915 struct process *pr = curproc->p_p; 1916 int s; 1917 1918 if (kn->kn_id >= NSIG) 1919 return EINVAL; 1920 1921 kn->kn_ptr.p_process = pr; 1922 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1923 1924 s = splhigh(); 1925 klist_insert_locked(&pr->ps_klist, kn); 1926 splx(s); 1927 1928 return (0); 1929 } 1930 1931 void 1932 filt_sigdetach(struct knote *kn) 1933 { 1934 struct process *pr = kn->kn_ptr.p_process; 1935 int s; 1936 1937 s = splhigh(); 1938 klist_remove_locked(&pr->ps_klist, kn); 1939 splx(s); 1940 } 1941 1942 /* 1943 * signal knotes are shared with proc knotes, so we apply a mask to 1944 * the hint in order to differentiate them from process hints. This 1945 * could be avoided by using a signal-specific knote list, but probably 1946 * isn't worth the trouble. 1947 */ 1948 int 1949 filt_signal(struct knote *kn, long hint) 1950 { 1951 1952 if (hint & NOTE_SIGNAL) { 1953 hint &= ~NOTE_SIGNAL; 1954 1955 if (kn->kn_id == hint) 1956 kn->kn_data++; 1957 } 1958 return (kn->kn_data != 0); 1959 } 1960 1961 void 1962 userret(struct proc *p) 1963 { 1964 struct sigctx ctx; 1965 int signum; 1966 1967 if (p->p_flag & P_SUSPSINGLE) 1968 single_thread_check(p, 0); 1969 1970 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1971 if (p->p_flag & P_PROFPEND) { 1972 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1973 KERNEL_LOCK(); 1974 psignal(p, SIGPROF); 1975 KERNEL_UNLOCK(); 1976 } 1977 if (p->p_flag & P_ALRMPEND) { 1978 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1979 KERNEL_LOCK(); 1980 psignal(p, SIGVTALRM); 1981 KERNEL_UNLOCK(); 1982 } 1983 1984 if (SIGPENDING(p) != 0) { 1985 while ((signum = cursig(p, &ctx)) != 0) 1986 postsig(p, signum, &ctx); 1987 } 1988 1989 /* 1990 * If P_SIGSUSPEND is still set here, then we still need to restore 1991 * the original sigmask before returning to userspace. Also, this 1992 * might unmask some pending signals, so we need to check a second 1993 * time for signals to post. 1994 */ 1995 if (p->p_flag & P_SIGSUSPEND) { 1996 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1997 p->p_sigmask = p->p_oldmask; 1998 1999 while ((signum = cursig(p, &ctx)) != 0) 2000 postsig(p, signum, &ctx); 2001 } 2002 2003 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2004 2005 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2006 } 2007 2008 int 2009 single_thread_check_locked(struct proc *p, int deep, int s) 2010 { 2011 struct process *pr = p->p_p; 2012 2013 SCHED_ASSERT_LOCKED(); 2014 2015 if (pr->ps_single == NULL || pr->ps_single == p) 2016 return (0); 2017 2018 do { 2019 /* if we're in deep, we need to unwind to the edge */ 2020 if (deep) { 2021 if (pr->ps_flags & PS_SINGLEUNWIND) 2022 return (ERESTART); 2023 if (pr->ps_flags & PS_SINGLEEXIT) 2024 return (EINTR); 2025 } 2026 2027 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2028 wakeup(&pr->ps_singlecount); 2029 2030 if (pr->ps_flags & PS_SINGLEEXIT) { 2031 SCHED_UNLOCK(s); 2032 KERNEL_LOCK(); 2033 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2034 /* NOTREACHED */ 2035 } 2036 2037 /* not exiting and don't need to unwind, so suspend */ 2038 p->p_stat = SSTOP; 2039 mi_switch(); 2040 } while (pr->ps_single != NULL); 2041 2042 return (0); 2043 } 2044 2045 int 2046 single_thread_check(struct proc *p, int deep) 2047 { 2048 int s, error; 2049 2050 SCHED_LOCK(s); 2051 error = single_thread_check_locked(p, deep, s); 2052 SCHED_UNLOCK(s); 2053 2054 return error; 2055 } 2056 2057 /* 2058 * Stop other threads in the process. The mode controls how and 2059 * where the other threads should stop: 2060 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2061 * single_thread_clear()) 2062 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2063 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2064 * - SINGLE_EXIT: unwind to kernel boundary and exit 2065 */ 2066 int 2067 single_thread_set(struct proc *p, int flags) 2068 { 2069 struct process *pr = p->p_p; 2070 struct proc *q; 2071 int error, s, mode = flags & SINGLE_MASK; 2072 2073 KASSERT(curproc == p); 2074 2075 SCHED_LOCK(s); 2076 error = single_thread_check_locked(p, flags & SINGLE_DEEP, s); 2077 if (error) { 2078 SCHED_UNLOCK(s); 2079 return error; 2080 } 2081 2082 switch (mode) { 2083 case SINGLE_SUSPEND: 2084 break; 2085 case SINGLE_UNWIND: 2086 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2087 break; 2088 case SINGLE_EXIT: 2089 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2090 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2091 break; 2092 #ifdef DIAGNOSTIC 2093 default: 2094 panic("single_thread_mode = %d", mode); 2095 #endif 2096 } 2097 pr->ps_singlecount = 0; 2098 membar_producer(); 2099 pr->ps_single = p; 2100 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2101 if (q == p) 2102 continue; 2103 if (q->p_flag & P_WEXIT) { 2104 if (mode == SINGLE_EXIT) { 2105 if (q->p_stat == SSTOP) { 2106 setrunnable(q); 2107 atomic_inc_int(&pr->ps_singlecount); 2108 } 2109 } 2110 continue; 2111 } 2112 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2113 switch (q->p_stat) { 2114 case SIDL: 2115 case SRUN: 2116 atomic_inc_int(&pr->ps_singlecount); 2117 break; 2118 case SSLEEP: 2119 /* if it's not interruptible, then just have to wait */ 2120 if (q->p_flag & P_SINTR) { 2121 /* merely need to suspend? just stop it */ 2122 if (mode == SINGLE_SUSPEND) { 2123 q->p_stat = SSTOP; 2124 break; 2125 } 2126 /* need to unwind or exit, so wake it */ 2127 setrunnable(q); 2128 } 2129 atomic_inc_int(&pr->ps_singlecount); 2130 break; 2131 case SSTOP: 2132 if (mode == SINGLE_EXIT) { 2133 setrunnable(q); 2134 atomic_inc_int(&pr->ps_singlecount); 2135 } 2136 break; 2137 case SDEAD: 2138 break; 2139 case SONPROC: 2140 atomic_inc_int(&pr->ps_singlecount); 2141 signotify(q); 2142 break; 2143 } 2144 } 2145 SCHED_UNLOCK(s); 2146 2147 if ((flags & SINGLE_NOWAIT) == 0) 2148 single_thread_wait(pr, 1); 2149 2150 return 0; 2151 } 2152 2153 /* 2154 * Wait for other threads to stop. If recheck is false then the function 2155 * returns non-zero if the caller needs to restart the check else 0 is 2156 * returned. If recheck is true the return value is always 0. 2157 */ 2158 int 2159 single_thread_wait(struct process *pr, int recheck) 2160 { 2161 int wait; 2162 2163 /* wait until they're all suspended */ 2164 wait = pr->ps_singlecount > 0; 2165 while (wait) { 2166 sleep_setup(&pr->ps_singlecount, PWAIT, "suspend"); 2167 wait = pr->ps_singlecount > 0; 2168 sleep_finish(0, wait); 2169 if (!recheck) 2170 break; 2171 } 2172 2173 return wait; 2174 } 2175 2176 void 2177 single_thread_clear(struct proc *p, int flag) 2178 { 2179 struct process *pr = p->p_p; 2180 struct proc *q; 2181 int s; 2182 2183 KASSERT(pr->ps_single == p); 2184 KASSERT(curproc == p); 2185 2186 SCHED_LOCK(s); 2187 pr->ps_single = NULL; 2188 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2189 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2190 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2191 continue; 2192 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2193 2194 /* 2195 * if the thread was only stopped for single threading 2196 * then clearing that either makes it runnable or puts 2197 * it back into some sleep queue 2198 */ 2199 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2200 if (q->p_wchan == NULL) 2201 setrunnable(q); 2202 else { 2203 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2204 q->p_stat = SSLEEP; 2205 } 2206 } 2207 } 2208 SCHED_UNLOCK(s); 2209 } 2210 2211 void 2212 sigio_del(struct sigiolst *rmlist) 2213 { 2214 struct sigio *sigio; 2215 2216 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2217 LIST_REMOVE(sigio, sio_pgsigio); 2218 crfree(sigio->sio_ucred); 2219 free(sigio, M_SIGIO, sizeof(*sigio)); 2220 } 2221 } 2222 2223 void 2224 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2225 { 2226 struct sigio *sigio; 2227 2228 MUTEX_ASSERT_LOCKED(&sigio_lock); 2229 2230 sigio = sir->sir_sigio; 2231 if (sigio != NULL) { 2232 KASSERT(sigio->sio_myref == sir); 2233 sir->sir_sigio = NULL; 2234 2235 if (sigio->sio_pgid > 0) 2236 sigio->sio_proc = NULL; 2237 else 2238 sigio->sio_pgrp = NULL; 2239 LIST_REMOVE(sigio, sio_pgsigio); 2240 2241 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2242 } 2243 } 2244 2245 void 2246 sigio_free(struct sigio_ref *sir) 2247 { 2248 struct sigiolst rmlist; 2249 2250 if (sir->sir_sigio == NULL) 2251 return; 2252 2253 LIST_INIT(&rmlist); 2254 2255 mtx_enter(&sigio_lock); 2256 sigio_unlink(sir, &rmlist); 2257 mtx_leave(&sigio_lock); 2258 2259 sigio_del(&rmlist); 2260 } 2261 2262 void 2263 sigio_freelist(struct sigiolst *sigiolst) 2264 { 2265 struct sigiolst rmlist; 2266 struct sigio *sigio; 2267 2268 if (LIST_EMPTY(sigiolst)) 2269 return; 2270 2271 LIST_INIT(&rmlist); 2272 2273 mtx_enter(&sigio_lock); 2274 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2275 sigio_unlink(sigio->sio_myref, &rmlist); 2276 mtx_leave(&sigio_lock); 2277 2278 sigio_del(&rmlist); 2279 } 2280 2281 int 2282 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2283 { 2284 struct sigiolst rmlist; 2285 struct proc *p = curproc; 2286 struct pgrp *pgrp = NULL; 2287 struct process *pr = NULL; 2288 struct sigio *sigio; 2289 int error; 2290 pid_t pgid = *(int *)data; 2291 2292 if (pgid == 0) { 2293 sigio_free(sir); 2294 return (0); 2295 } 2296 2297 if (cmd == TIOCSPGRP) { 2298 if (pgid < 0) 2299 return (EINVAL); 2300 pgid = -pgid; 2301 } 2302 2303 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2304 sigio->sio_pgid = pgid; 2305 sigio->sio_ucred = crhold(p->p_ucred); 2306 sigio->sio_myref = sir; 2307 2308 LIST_INIT(&rmlist); 2309 2310 /* 2311 * The kernel lock, and not sleeping between prfind()/pgfind() and 2312 * linking of the sigio ensure that the process or process group does 2313 * not disappear unexpectedly. 2314 */ 2315 KERNEL_LOCK(); 2316 mtx_enter(&sigio_lock); 2317 2318 if (pgid > 0) { 2319 pr = prfind(pgid); 2320 if (pr == NULL) { 2321 error = ESRCH; 2322 goto fail; 2323 } 2324 2325 /* 2326 * Policy - Don't allow a process to FSETOWN a process 2327 * in another session. 2328 * 2329 * Remove this test to allow maximum flexibility or 2330 * restrict FSETOWN to the current process or process 2331 * group for maximum safety. 2332 */ 2333 if (pr->ps_session != p->p_p->ps_session) { 2334 error = EPERM; 2335 goto fail; 2336 } 2337 2338 if ((pr->ps_flags & PS_EXITING) != 0) { 2339 error = ESRCH; 2340 goto fail; 2341 } 2342 } else /* if (pgid < 0) */ { 2343 pgrp = pgfind(-pgid); 2344 if (pgrp == NULL) { 2345 error = ESRCH; 2346 goto fail; 2347 } 2348 2349 /* 2350 * Policy - Don't allow a process to FSETOWN a process 2351 * in another session. 2352 * 2353 * Remove this test to allow maximum flexibility or 2354 * restrict FSETOWN to the current process or process 2355 * group for maximum safety. 2356 */ 2357 if (pgrp->pg_session != p->p_p->ps_session) { 2358 error = EPERM; 2359 goto fail; 2360 } 2361 } 2362 2363 if (pgid > 0) { 2364 sigio->sio_proc = pr; 2365 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2366 } else { 2367 sigio->sio_pgrp = pgrp; 2368 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2369 } 2370 2371 sigio_unlink(sir, &rmlist); 2372 sir->sir_sigio = sigio; 2373 2374 mtx_leave(&sigio_lock); 2375 KERNEL_UNLOCK(); 2376 2377 sigio_del(&rmlist); 2378 2379 return (0); 2380 2381 fail: 2382 mtx_leave(&sigio_lock); 2383 KERNEL_UNLOCK(); 2384 2385 crfree(sigio->sio_ucred); 2386 free(sigio, M_SIGIO, sizeof(*sigio)); 2387 2388 return (error); 2389 } 2390 2391 void 2392 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2393 { 2394 struct sigio *sigio; 2395 pid_t pgid = 0; 2396 2397 mtx_enter(&sigio_lock); 2398 sigio = sir->sir_sigio; 2399 if (sigio != NULL) 2400 pgid = sigio->sio_pgid; 2401 mtx_leave(&sigio_lock); 2402 2403 if (cmd == TIOCGPGRP) 2404 pgid = -pgid; 2405 2406 *(int *)data = pgid; 2407 } 2408 2409 void 2410 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2411 { 2412 struct sigiolst rmlist; 2413 struct sigio *newsigio, *sigio; 2414 2415 sigio_free(dst); 2416 2417 if (src->sir_sigio == NULL) 2418 return; 2419 2420 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2421 LIST_INIT(&rmlist); 2422 2423 mtx_enter(&sigio_lock); 2424 2425 sigio = src->sir_sigio; 2426 if (sigio == NULL) { 2427 mtx_leave(&sigio_lock); 2428 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2429 return; 2430 } 2431 2432 newsigio->sio_pgid = sigio->sio_pgid; 2433 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2434 newsigio->sio_myref = dst; 2435 if (newsigio->sio_pgid > 0) { 2436 newsigio->sio_proc = sigio->sio_proc; 2437 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2438 sio_pgsigio); 2439 } else { 2440 newsigio->sio_pgrp = sigio->sio_pgrp; 2441 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2442 sio_pgsigio); 2443 } 2444 2445 sigio_unlink(dst, &rmlist); 2446 dst->sir_sigio = newsigio; 2447 2448 mtx_leave(&sigio_lock); 2449 2450 sigio_del(&rmlist); 2451 } 2452