1 /* $OpenBSD: kern_sig.c,v 1.336 2024/07/29 12:42:53 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 /* 74 * The array below categorizes the signals and their default actions. 75 */ 76 const int sigprop[NSIG] = { 77 0, /* unused */ 78 SA_KILL, /* SIGHUP */ 79 SA_KILL, /* SIGINT */ 80 SA_KILL|SA_CORE, /* SIGQUIT */ 81 SA_KILL|SA_CORE, /* SIGILL */ 82 SA_KILL|SA_CORE, /* SIGTRAP */ 83 SA_KILL|SA_CORE, /* SIGABRT */ 84 SA_KILL|SA_CORE, /* SIGEMT */ 85 SA_KILL|SA_CORE, /* SIGFPE */ 86 SA_KILL, /* SIGKILL */ 87 SA_KILL|SA_CORE, /* SIGBUS */ 88 SA_KILL|SA_CORE, /* SIGSEGV */ 89 SA_KILL|SA_CORE, /* SIGSYS */ 90 SA_KILL, /* SIGPIPE */ 91 SA_KILL, /* SIGALRM */ 92 SA_KILL, /* SIGTERM */ 93 SA_IGNORE, /* SIGURG */ 94 SA_STOP, /* SIGSTOP */ 95 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 96 SA_IGNORE|SA_CONT, /* SIGCONT */ 97 SA_IGNORE, /* SIGCHLD */ 98 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 99 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 100 SA_IGNORE, /* SIGIO */ 101 SA_KILL, /* SIGXCPU */ 102 SA_KILL, /* SIGXFSZ */ 103 SA_KILL, /* SIGVTALRM */ 104 SA_KILL, /* SIGPROF */ 105 SA_IGNORE, /* SIGWINCH */ 106 SA_IGNORE, /* SIGINFO */ 107 SA_KILL, /* SIGUSR1 */ 108 SA_KILL, /* SIGUSR2 */ 109 SA_IGNORE, /* SIGTHR */ 110 }; 111 112 #define CONTSIGMASK (sigmask(SIGCONT)) 113 #define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 114 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 115 116 void setsigvec(struct proc *, int, struct sigaction *); 117 118 void proc_stop(struct proc *p, int); 119 void proc_stop_sweep(void *); 120 void *proc_stop_si; 121 122 void setsigctx(struct proc *, int, struct sigctx *); 123 void postsig_done(struct proc *, int, sigset_t, int); 124 void postsig(struct proc *, int, struct sigctx *); 125 int cansignal(struct proc *, struct process *, int); 126 127 struct pool sigacts_pool; /* memory pool for sigacts structures */ 128 129 void sigio_del(struct sigiolst *); 130 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 131 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 132 133 /* 134 * Can thread p, send the signal signum to process qr? 135 */ 136 int 137 cansignal(struct proc *p, struct process *qr, int signum) 138 { 139 struct process *pr = p->p_p; 140 struct ucred *uc = p->p_ucred; 141 struct ucred *quc = qr->ps_ucred; 142 143 if (uc->cr_uid == 0) 144 return (1); /* root can always signal */ 145 146 if (pr == qr) 147 return (1); /* process can always signal itself */ 148 149 /* optimization: if the same creds then the tests below will pass */ 150 if (uc == quc) 151 return (1); 152 153 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 154 return (1); /* SIGCONT in session */ 155 156 /* 157 * Using kill(), only certain signals can be sent to setugid 158 * child processes 159 */ 160 if (qr->ps_flags & PS_SUGID) { 161 switch (signum) { 162 case 0: 163 case SIGKILL: 164 case SIGINT: 165 case SIGTERM: 166 case SIGALRM: 167 case SIGSTOP: 168 case SIGTTIN: 169 case SIGTTOU: 170 case SIGTSTP: 171 case SIGHUP: 172 case SIGUSR1: 173 case SIGUSR2: 174 if (uc->cr_ruid == quc->cr_ruid || 175 uc->cr_uid == quc->cr_ruid) 176 return (1); 177 } 178 return (0); 179 } 180 181 if (uc->cr_ruid == quc->cr_ruid || 182 uc->cr_ruid == quc->cr_svuid || 183 uc->cr_uid == quc->cr_ruid || 184 uc->cr_uid == quc->cr_svuid) 185 return (1); 186 return (0); 187 } 188 189 /* 190 * Initialize signal-related data structures. 191 */ 192 void 193 signal_init(void) 194 { 195 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 196 NULL); 197 if (proc_stop_si == NULL) 198 panic("signal_init failed to register softintr"); 199 200 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 201 PR_WAITOK, "sigapl", NULL); 202 } 203 204 /* 205 * Initialize a new sigaltstack structure. 206 */ 207 void 208 sigstkinit(struct sigaltstack *ss) 209 { 210 ss->ss_flags = SS_DISABLE; 211 ss->ss_size = 0; 212 ss->ss_sp = NULL; 213 } 214 215 /* 216 * Create an initial sigacts structure, using the same signal state 217 * as pr. 218 */ 219 struct sigacts * 220 sigactsinit(struct process *pr) 221 { 222 struct sigacts *ps; 223 224 ps = pool_get(&sigacts_pool, PR_WAITOK); 225 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 226 return (ps); 227 } 228 229 /* 230 * Release a sigacts structure. 231 */ 232 void 233 sigactsfree(struct sigacts *ps) 234 { 235 pool_put(&sigacts_pool, ps); 236 } 237 238 int 239 sys_sigaction(struct proc *p, void *v, register_t *retval) 240 { 241 struct sys_sigaction_args /* { 242 syscallarg(int) signum; 243 syscallarg(const struct sigaction *) nsa; 244 syscallarg(struct sigaction *) osa; 245 } */ *uap = v; 246 struct sigaction vec; 247 #ifdef KTRACE 248 struct sigaction ovec; 249 #endif 250 struct sigaction *sa; 251 const struct sigaction *nsa; 252 struct sigaction *osa; 253 struct sigacts *ps = p->p_p->ps_sigacts; 254 int signum; 255 int bit, error; 256 257 signum = SCARG(uap, signum); 258 nsa = SCARG(uap, nsa); 259 osa = SCARG(uap, osa); 260 261 if (signum <= 0 || signum >= NSIG || 262 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 263 return (EINVAL); 264 sa = &vec; 265 if (osa) { 266 mtx_enter(&p->p_p->ps_mtx); 267 sa->sa_handler = ps->ps_sigact[signum]; 268 sa->sa_mask = ps->ps_catchmask[signum]; 269 bit = sigmask(signum); 270 sa->sa_flags = 0; 271 if ((ps->ps_sigonstack & bit) != 0) 272 sa->sa_flags |= SA_ONSTACK; 273 if ((ps->ps_sigintr & bit) == 0) 274 sa->sa_flags |= SA_RESTART; 275 if ((ps->ps_sigreset & bit) != 0) 276 sa->sa_flags |= SA_RESETHAND; 277 if ((ps->ps_siginfo & bit) != 0) 278 sa->sa_flags |= SA_SIGINFO; 279 if (signum == SIGCHLD) { 280 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 281 sa->sa_flags |= SA_NOCLDSTOP; 282 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 283 sa->sa_flags |= SA_NOCLDWAIT; 284 } 285 mtx_leave(&p->p_p->ps_mtx); 286 if ((sa->sa_mask & bit) == 0) 287 sa->sa_flags |= SA_NODEFER; 288 sa->sa_mask &= ~bit; 289 error = copyout(sa, osa, sizeof (vec)); 290 if (error) 291 return (error); 292 #ifdef KTRACE 293 if (KTRPOINT(p, KTR_STRUCT)) 294 ovec = vec; 295 #endif 296 } 297 if (nsa) { 298 error = copyin(nsa, sa, sizeof (vec)); 299 if (error) 300 return (error); 301 #ifdef KTRACE 302 if (KTRPOINT(p, KTR_STRUCT)) 303 ktrsigaction(p, sa); 304 #endif 305 setsigvec(p, signum, sa); 306 } 307 #ifdef KTRACE 308 if (osa && KTRPOINT(p, KTR_STRUCT)) 309 ktrsigaction(p, &ovec); 310 #endif 311 return (0); 312 } 313 314 void 315 setsigvec(struct proc *p, int signum, struct sigaction *sa) 316 { 317 struct sigacts *ps = p->p_p->ps_sigacts; 318 int bit; 319 320 bit = sigmask(signum); 321 322 mtx_enter(&p->p_p->ps_mtx); 323 ps->ps_sigact[signum] = sa->sa_handler; 324 if ((sa->sa_flags & SA_NODEFER) == 0) 325 sa->sa_mask |= sigmask(signum); 326 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 327 if (signum == SIGCHLD) { 328 if (sa->sa_flags & SA_NOCLDSTOP) 329 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 330 else 331 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 332 /* 333 * If the SA_NOCLDWAIT flag is set or the handler 334 * is SIG_IGN we reparent the dying child to PID 1 335 * (init) which will reap the zombie. Because we use 336 * init to do our dirty work we never set SAS_NOCLDWAIT 337 * for PID 1. 338 * XXX exit1 rework means this is unnecessary? 339 */ 340 if (initprocess->ps_sigacts != ps && 341 ((sa->sa_flags & SA_NOCLDWAIT) || 342 sa->sa_handler == SIG_IGN)) 343 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 344 else 345 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 346 } 347 if ((sa->sa_flags & SA_RESETHAND) != 0) 348 ps->ps_sigreset |= bit; 349 else 350 ps->ps_sigreset &= ~bit; 351 if ((sa->sa_flags & SA_SIGINFO) != 0) 352 ps->ps_siginfo |= bit; 353 else 354 ps->ps_siginfo &= ~bit; 355 if ((sa->sa_flags & SA_RESTART) == 0) 356 ps->ps_sigintr |= bit; 357 else 358 ps->ps_sigintr &= ~bit; 359 if ((sa->sa_flags & SA_ONSTACK) != 0) 360 ps->ps_sigonstack |= bit; 361 else 362 ps->ps_sigonstack &= ~bit; 363 /* 364 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 365 * and for signals set to SIG_DFL where the default is to ignore. 366 * However, don't put SIGCONT in ps_sigignore, 367 * as we have to restart the process. 368 */ 369 if (sa->sa_handler == SIG_IGN || 370 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 371 atomic_clearbits_int(&p->p_siglist, bit); 372 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 373 if (signum != SIGCONT) 374 ps->ps_sigignore |= bit; /* easier in psignal */ 375 ps->ps_sigcatch &= ~bit; 376 } else { 377 ps->ps_sigignore &= ~bit; 378 if (sa->sa_handler == SIG_DFL) 379 ps->ps_sigcatch &= ~bit; 380 else 381 ps->ps_sigcatch |= bit; 382 } 383 mtx_leave(&p->p_p->ps_mtx); 384 } 385 386 /* 387 * Initialize signal state for process 0; 388 * set to ignore signals that are ignored by default. 389 */ 390 void 391 siginit(struct sigacts *ps) 392 { 393 int i; 394 395 for (i = 0; i < NSIG; i++) 396 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 397 ps->ps_sigignore |= sigmask(i); 398 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 399 } 400 401 /* 402 * Reset signals for an exec by the specified thread. 403 */ 404 void 405 execsigs(struct proc *p) 406 { 407 struct sigacts *ps; 408 int nc, mask; 409 410 ps = p->p_p->ps_sigacts; 411 mtx_enter(&p->p_p->ps_mtx); 412 413 /* 414 * Reset caught signals. Held signals remain held 415 * through p_sigmask (unless they were caught, 416 * and are now ignored by default). 417 */ 418 while (ps->ps_sigcatch) { 419 nc = ffs((long)ps->ps_sigcatch); 420 mask = sigmask(nc); 421 ps->ps_sigcatch &= ~mask; 422 if (sigprop[nc] & SA_IGNORE) { 423 if (nc != SIGCONT) 424 ps->ps_sigignore |= mask; 425 atomic_clearbits_int(&p->p_siglist, mask); 426 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 427 } 428 ps->ps_sigact[nc] = SIG_DFL; 429 } 430 /* 431 * Reset stack state to the user stack. 432 * Clear set of signals caught on the signal stack. 433 */ 434 sigstkinit(&p->p_sigstk); 435 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 436 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 437 ps->ps_sigact[SIGCHLD] = SIG_DFL; 438 mtx_leave(&p->p_p->ps_mtx); 439 } 440 441 /* 442 * Manipulate signal mask. 443 * Note that we receive new mask, not pointer, 444 * and return old mask as return value; 445 * the library stub does the rest. 446 */ 447 int 448 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 449 { 450 struct sys_sigprocmask_args /* { 451 syscallarg(int) how; 452 syscallarg(sigset_t) mask; 453 } */ *uap = v; 454 int error = 0; 455 sigset_t mask; 456 457 KASSERT(p == curproc); 458 459 *retval = p->p_sigmask; 460 mask = SCARG(uap, mask) &~ sigcantmask; 461 462 switch (SCARG(uap, how)) { 463 case SIG_BLOCK: 464 SET(p->p_sigmask, mask); 465 break; 466 case SIG_UNBLOCK: 467 CLR(p->p_sigmask, mask); 468 break; 469 case SIG_SETMASK: 470 p->p_sigmask = mask; 471 break; 472 default: 473 error = EINVAL; 474 break; 475 } 476 return (error); 477 } 478 479 int 480 sys_sigpending(struct proc *p, void *v, register_t *retval) 481 { 482 *retval = p->p_siglist | p->p_p->ps_siglist; 483 return (0); 484 } 485 486 /* 487 * Temporarily replace calling proc's signal mask for the duration of a 488 * system call. Original signal mask will be restored by userret(). 489 */ 490 void 491 dosigsuspend(struct proc *p, sigset_t newmask) 492 { 493 KASSERT(p == curproc); 494 495 p->p_oldmask = p->p_sigmask; 496 p->p_sigmask = newmask; 497 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 498 } 499 500 /* 501 * Suspend thread until signal, providing mask to be set 502 * in the meantime. Note nonstandard calling convention: 503 * libc stub passes mask, not pointer, to save a copyin. 504 */ 505 int 506 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 507 { 508 struct sys_sigsuspend_args /* { 509 syscallarg(int) mask; 510 } */ *uap = v; 511 512 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 513 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 514 continue; 515 /* always return EINTR rather than ERESTART... */ 516 return (EINTR); 517 } 518 519 int 520 sigonstack(size_t stack) 521 { 522 const struct sigaltstack *ss = &curproc->p_sigstk; 523 524 return (ss->ss_flags & SS_DISABLE ? 0 : 525 (stack - (size_t)ss->ss_sp < ss->ss_size)); 526 } 527 528 int 529 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 530 { 531 struct sys_sigaltstack_args /* { 532 syscallarg(const struct sigaltstack *) nss; 533 syscallarg(struct sigaltstack *) oss; 534 } */ *uap = v; 535 struct sigaltstack ss; 536 const struct sigaltstack *nss; 537 struct sigaltstack *oss; 538 int onstack = sigonstack(PROC_STACK(p)); 539 int error; 540 541 nss = SCARG(uap, nss); 542 oss = SCARG(uap, oss); 543 544 if (oss != NULL) { 545 ss = p->p_sigstk; 546 if (onstack) 547 ss.ss_flags |= SS_ONSTACK; 548 if ((error = copyout(&ss, oss, sizeof(ss)))) 549 return (error); 550 } 551 if (nss == NULL) 552 return (0); 553 error = copyin(nss, &ss, sizeof(ss)); 554 if (error) 555 return (error); 556 if (onstack) 557 return (EPERM); 558 if (ss.ss_flags & ~SS_DISABLE) 559 return (EINVAL); 560 if (ss.ss_flags & SS_DISABLE) { 561 p->p_sigstk.ss_flags = ss.ss_flags; 562 return (0); 563 } 564 if (ss.ss_size < MINSIGSTKSZ) 565 return (ENOMEM); 566 567 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 568 if (error) 569 return (error); 570 571 p->p_sigstk = ss; 572 return (0); 573 } 574 575 int 576 sys_kill(struct proc *cp, void *v, register_t *retval) 577 { 578 struct sys_kill_args /* { 579 syscallarg(int) pid; 580 syscallarg(int) signum; 581 } */ *uap = v; 582 struct process *pr; 583 int pid = SCARG(uap, pid); 584 int signum = SCARG(uap, signum); 585 int error; 586 int zombie = 0; 587 588 if ((error = pledge_kill(cp, pid)) != 0) 589 return (error); 590 if (((u_int)signum) >= NSIG) 591 return (EINVAL); 592 if (pid > 0) { 593 if ((pr = prfind(pid)) == NULL) { 594 if ((pr = zombiefind(pid)) == NULL) 595 return (ESRCH); 596 else 597 zombie = 1; 598 } 599 if (!cansignal(cp, pr, signum)) 600 return (EPERM); 601 602 /* kill single process */ 603 if (signum && !zombie) 604 prsignal(pr, signum); 605 return (0); 606 } 607 switch (pid) { 608 case -1: /* broadcast signal */ 609 return (killpg1(cp, signum, 0, 1)); 610 case 0: /* signal own process group */ 611 return (killpg1(cp, signum, 0, 0)); 612 default: /* negative explicit process group */ 613 return (killpg1(cp, signum, -pid, 0)); 614 } 615 } 616 617 int 618 sys_thrkill(struct proc *cp, void *v, register_t *retval) 619 { 620 struct sys_thrkill_args /* { 621 syscallarg(pid_t) tid; 622 syscallarg(int) signum; 623 syscallarg(void *) tcb; 624 } */ *uap = v; 625 struct proc *p; 626 int tid = SCARG(uap, tid); 627 int signum = SCARG(uap, signum); 628 void *tcb; 629 630 if (((u_int)signum) >= NSIG) 631 return (EINVAL); 632 633 p = tid ? tfind_user(tid, cp->p_p) : cp; 634 if (p == NULL) 635 return (ESRCH); 636 637 /* optionally require the target thread to have the given tcb addr */ 638 tcb = SCARG(uap, tcb); 639 if (tcb != NULL && tcb != TCB_GET(p)) 640 return (ESRCH); 641 642 if (signum) 643 ptsignal(p, signum, STHREAD); 644 return (0); 645 } 646 647 /* 648 * Common code for kill process group/broadcast kill. 649 * cp is calling process. 650 */ 651 int 652 killpg1(struct proc *cp, int signum, int pgid, int all) 653 { 654 struct process *pr; 655 struct pgrp *pgrp; 656 int nfound = 0; 657 658 if (all) { 659 /* 660 * broadcast 661 */ 662 LIST_FOREACH(pr, &allprocess, ps_list) { 663 if (pr->ps_pid <= 1 || 664 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 665 pr == cp->p_p || !cansignal(cp, pr, signum)) 666 continue; 667 nfound++; 668 if (signum) 669 prsignal(pr, signum); 670 } 671 } else { 672 if (pgid == 0) 673 /* 674 * zero pgid means send to my process group. 675 */ 676 pgrp = cp->p_p->ps_pgrp; 677 else { 678 pgrp = pgfind(pgid); 679 if (pgrp == NULL) 680 return (ESRCH); 681 } 682 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 683 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 684 !cansignal(cp, pr, signum)) 685 continue; 686 nfound++; 687 if (signum) 688 prsignal(pr, signum); 689 } 690 } 691 return (nfound ? 0 : ESRCH); 692 } 693 694 #define CANDELIVER(uid, euid, pr) \ 695 (euid == 0 || \ 696 (uid) == (pr)->ps_ucred->cr_ruid || \ 697 (uid) == (pr)->ps_ucred->cr_svuid || \ 698 (uid) == (pr)->ps_ucred->cr_uid || \ 699 (euid) == (pr)->ps_ucred->cr_ruid || \ 700 (euid) == (pr)->ps_ucred->cr_svuid || \ 701 (euid) == (pr)->ps_ucred->cr_uid) 702 703 #define CANSIGIO(cr, pr) \ 704 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 705 706 /* 707 * Send a signal to a process group. If checktty is 1, 708 * limit to members which have a controlling terminal. 709 */ 710 void 711 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 712 { 713 struct process *pr; 714 715 if (pgrp) 716 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 717 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 718 prsignal(pr, signum); 719 } 720 721 /* 722 * Send a SIGIO or SIGURG signal to a process or process group using stored 723 * credentials rather than those of the current process. 724 */ 725 void 726 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 727 { 728 struct process *pr; 729 struct sigio *sigio; 730 731 if (sir->sir_sigio == NULL) 732 return; 733 734 KERNEL_LOCK(); 735 mtx_enter(&sigio_lock); 736 sigio = sir->sir_sigio; 737 if (sigio == NULL) 738 goto out; 739 if (sigio->sio_pgid > 0) { 740 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 741 prsignal(sigio->sio_proc, sig); 742 } else if (sigio->sio_pgid < 0) { 743 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 744 if (CANSIGIO(sigio->sio_ucred, pr) && 745 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 746 prsignal(pr, sig); 747 } 748 } 749 out: 750 mtx_leave(&sigio_lock); 751 KERNEL_UNLOCK(); 752 } 753 754 /* 755 * Recalculate the signal mask and reset the signal disposition after 756 * usermode frame for delivery is formed. 757 */ 758 void 759 postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 760 { 761 p->p_ru.ru_nsignals++; 762 SET(p->p_sigmask, catchmask); 763 if (reset != 0) { 764 sigset_t mask = sigmask(signum); 765 struct sigacts *ps = p->p_p->ps_sigacts; 766 767 mtx_enter(&p->p_p->ps_mtx); 768 ps->ps_sigcatch &= ~mask; 769 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 770 ps->ps_sigignore |= mask; 771 ps->ps_sigact[signum] = SIG_DFL; 772 mtx_leave(&p->p_p->ps_mtx); 773 } 774 } 775 776 /* 777 * Send a signal caused by a trap to the current thread 778 * If it will be caught immediately, deliver it with correct code. 779 * Otherwise, post it normally. 780 */ 781 void 782 trapsignal(struct proc *p, int signum, u_long trapno, int code, 783 union sigval sigval) 784 { 785 struct process *pr = p->p_p; 786 struct sigctx ctx; 787 int mask; 788 789 switch (signum) { 790 case SIGILL: 791 if (code == ILL_BTCFI) { 792 pr->ps_acflag |= ABTCFI; 793 break; 794 } 795 /* FALLTHROUGH */ 796 case SIGBUS: 797 case SIGSEGV: 798 pr->ps_acflag |= ATRAP; 799 break; 800 } 801 802 mask = sigmask(signum); 803 setsigctx(p, signum, &ctx); 804 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 805 (p->p_sigmask & mask) == 0) { 806 siginfo_t si; 807 808 initsiginfo(&si, signum, trapno, code, sigval); 809 #ifdef KTRACE 810 if (KTRPOINT(p, KTR_PSIG)) { 811 ktrpsig(p, signum, ctx.sig_action, 812 p->p_sigmask, code, &si); 813 } 814 #endif 815 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 816 ctx.sig_info, ctx.sig_onstack)) { 817 KERNEL_LOCK(); 818 sigexit(p, SIGILL); 819 /* NOTREACHED */ 820 } 821 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 822 } else { 823 p->p_sisig = signum; 824 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 825 p->p_sicode = code; 826 p->p_sigval = sigval; 827 828 /* 829 * If traced, stop if signal is masked, and stay stopped 830 * until released by the debugger. If our parent process 831 * is waiting for us, don't hang as we could deadlock. 832 */ 833 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 834 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 835 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 836 pr->ps_xsig = signum; 837 838 SCHED_LOCK(); 839 proc_stop(p, 1); 840 SCHED_UNLOCK(); 841 842 signum = pr->ps_xsig; 843 single_thread_clear(p, 0); 844 845 /* 846 * If we are no longer being traced, or the parent 847 * didn't give us a signal, skip sending the signal. 848 */ 849 if ((pr->ps_flags & PS_TRACED) == 0 || 850 signum == 0) 851 return; 852 853 /* update signal info */ 854 p->p_sisig = signum; 855 mask = sigmask(signum); 856 } 857 858 /* 859 * Signals like SIGBUS and SIGSEGV should not, when 860 * generated by the kernel, be ignorable or blockable. 861 * If it is and we're not being traced, then just kill 862 * the process. 863 * After vfs_shutdown(9), init(8) cannot receive signals 864 * because new code pages of the signal handler cannot be 865 * mapped from halted storage. init(8) may not die or the 866 * kernel panics. Better loop between signal handler and 867 * page fault trap until the machine is halted. 868 */ 869 if ((pr->ps_flags & PS_TRACED) == 0 && 870 (sigprop[signum] & SA_KILL) && 871 ((p->p_sigmask & mask) || ctx.sig_ignore) && 872 pr->ps_pid != 1) { 873 KERNEL_LOCK(); 874 sigexit(p, signum); 875 /* NOTREACHED */ 876 } 877 KERNEL_LOCK(); 878 ptsignal(p, signum, STHREAD); 879 KERNEL_UNLOCK(); 880 } 881 } 882 883 /* 884 * Send the signal to the process. If the signal has an action, the action 885 * is usually performed by the target process rather than the caller; we add 886 * the signal to the set of pending signals for the process. 887 * 888 * Exceptions: 889 * o When a stop signal is sent to a sleeping process that takes the 890 * default action, the process is stopped without awakening it. 891 * o SIGCONT restarts stopped processes (or puts them back to sleep) 892 * regardless of the signal action (eg, blocked or ignored). 893 * 894 * Other ignored signals are discarded immediately. 895 */ 896 void 897 psignal(struct proc *p, int signum) 898 { 899 ptsignal(p, signum, SPROCESS); 900 } 901 902 /* 903 * type = SPROCESS process signal, can be diverted (sigwait()) 904 * type = STHREAD thread signal, but should be propagated if unhandled 905 * type = SPROPAGATED propagated to this thread, so don't propagate again 906 */ 907 void 908 ptsignal(struct proc *p, int signum, enum signal_type type) 909 { 910 int prop; 911 sig_t action, altaction = SIG_DFL; 912 sigset_t mask, sigmask; 913 int *siglist; 914 struct process *pr = p->p_p; 915 struct proc *q; 916 int wakeparent = 0; 917 918 KERNEL_ASSERT_LOCKED(); 919 920 #ifdef DIAGNOSTIC 921 if ((u_int)signum >= NSIG || signum == 0) 922 panic("psignal signal number"); 923 #endif 924 925 /* Ignore signal if the target process is exiting */ 926 if (pr->ps_flags & PS_EXITING) 927 return; 928 929 mask = sigmask(signum); 930 sigmask = READ_ONCE(p->p_sigmask); 931 932 if (type == SPROCESS) { 933 sigset_t tmpmask; 934 935 /* Accept SIGKILL to coredumping processes */ 936 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 937 atomic_setbits_int(&pr->ps_siglist, mask); 938 return; 939 } 940 941 /* 942 * If the current thread can process the signal 943 * immediately (it's unblocked) then have it take it. 944 */ 945 q = curproc; 946 tmpmask = READ_ONCE(q->p_sigmask); 947 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 948 (tmpmask & mask) == 0) { 949 p = q; 950 sigmask = tmpmask; 951 } else { 952 /* 953 * A process-wide signal can be diverted to a 954 * different thread that's in sigwait() for this 955 * signal. If there isn't such a thread, then 956 * pick a thread that doesn't have it blocked so 957 * that the stop/kill consideration isn't 958 * delayed. Otherwise, mark it pending on the 959 * main thread. 960 */ 961 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 962 963 /* ignore exiting threads */ 964 if (q->p_flag & P_WEXIT) 965 continue; 966 967 /* skip threads that have the signal blocked */ 968 tmpmask = READ_ONCE(q->p_sigmask); 969 if ((tmpmask & mask) != 0) 970 continue; 971 972 /* okay, could send to this thread */ 973 p = q; 974 sigmask = tmpmask; 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 (sigmask & mask) { 1015 action = SIG_HOLD; 1016 if (sigcatch & mask) 1017 altaction = SIG_CATCH; 1018 } else if (sigcatch & mask) { 1019 action = SIG_CATCH; 1020 } else { 1021 action = SIG_DFL; 1022 1023 if (prop & SA_KILL && pr->ps_nice > NZERO) 1024 pr->ps_nice = NZERO; 1025 1026 /* 1027 * If sending a tty stop signal to a member of an 1028 * orphaned process group, discard the signal here if 1029 * the action is default; don't stop the process below 1030 * if sleeping, and don't clear any pending SIGCONT. 1031 */ 1032 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1033 return; 1034 } 1035 } 1036 /* 1037 * If delivered to process, mark as pending there. Continue and stop 1038 * signals will be propagated to all threads. So they are always 1039 * marked at thread level. 1040 */ 1041 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1042 if (prop & (SA_CONT | SA_STOP)) 1043 siglist = &p->p_siglist; 1044 1045 /* 1046 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1047 */ 1048 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1049 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1050 if (q != p) 1051 ptsignal(q, signum, SPROPAGATED); 1052 1053 SCHED_LOCK(); 1054 1055 switch (p->p_stat) { 1056 1057 case SSTOP: 1058 /* 1059 * If traced process is already stopped, 1060 * then no further action is necessary. 1061 */ 1062 if (pr->ps_flags & PS_TRACED) 1063 goto out; 1064 1065 /* 1066 * Kill signal always sets processes running. 1067 */ 1068 if (signum == SIGKILL) { 1069 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1070 /* Raise priority to at least PUSER. */ 1071 if (p->p_usrpri > PUSER) 1072 p->p_usrpri = PUSER; 1073 unsleep(p); 1074 setrunnable(p); 1075 goto out; 1076 } 1077 1078 if (prop & SA_CONT) { 1079 /* 1080 * If SIGCONT is default (or ignored), we continue the 1081 * process but don't leave the signal in p_siglist, as 1082 * it has no further action. If SIGCONT is held, we 1083 * continue the process and leave the signal in 1084 * p_siglist. If the process catches SIGCONT, let it 1085 * handle the signal itself. If it isn't waiting on 1086 * an event, then it goes back to run state. 1087 * Otherwise, process goes back to sleep state. 1088 */ 1089 atomic_setbits_int(&pr->ps_flags, PS_CONTINUED); 1090 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1091 wakeparent = 1; 1092 if (action == SIG_DFL) 1093 mask = 0; 1094 if (action == SIG_CATCH) { 1095 /* Raise priority to at least PUSER. */ 1096 if (p->p_usrpri > PUSER) 1097 p->p_usrpri = PUSER; 1098 unsleep(p); 1099 setrunnable(p); 1100 goto out; 1101 } 1102 if (p->p_wchan == NULL) { 1103 unsleep(p); 1104 setrunnable(p); 1105 goto out; 1106 } 1107 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1108 p->p_stat = SSLEEP; 1109 goto out; 1110 } 1111 1112 /* 1113 * Defer further processing for signals which are held, 1114 * except that stopped processes must be continued by SIGCONT. 1115 */ 1116 if (action == SIG_HOLD) 1117 goto out; 1118 1119 if (prop & SA_STOP) { 1120 /* 1121 * Already stopped, don't need to stop again. 1122 * (If we did the shell could get confused.) 1123 */ 1124 mask = 0; 1125 goto out; 1126 } 1127 1128 /* 1129 * If process is sleeping interruptibly, then simulate a 1130 * wakeup so that when it is continued, it will be made 1131 * runnable and can look at the signal. But don't make 1132 * the process runnable, leave it stopped. 1133 */ 1134 if (p->p_flag & P_SINTR) 1135 unsleep(p); 1136 goto out; 1137 1138 case SSLEEP: 1139 /* 1140 * If process is sleeping uninterruptibly 1141 * we can't interrupt the sleep... the signal will 1142 * be noticed when the process returns through 1143 * trap() or syscall(). 1144 */ 1145 if ((p->p_flag & P_SINTR) == 0) 1146 goto out; 1147 /* 1148 * Process is sleeping and traced... make it runnable 1149 * so it can discover the signal in cursig() and stop 1150 * for the parent. 1151 */ 1152 if (pr->ps_flags & PS_TRACED) { 1153 unsleep(p); 1154 setrunnable(p); 1155 goto out; 1156 } 1157 1158 /* 1159 * Recheck sigmask before waking up the process, 1160 * there is a chance that while sending the signal 1161 * the process changed sigmask and went to sleep. 1162 */ 1163 sigmask = READ_ONCE(p->p_sigmask); 1164 if (sigmask & mask) 1165 goto out; 1166 else if (action == SIG_HOLD) { 1167 /* signal got unmasked, get proper action */ 1168 action = altaction; 1169 1170 if (action == SIG_DFL) { 1171 if (prop & SA_KILL && pr->ps_nice > NZERO) 1172 pr->ps_nice = NZERO; 1173 1174 /* 1175 * Discard tty stop signals sent to an 1176 * orphaned process group, see above. 1177 */ 1178 if (prop & SA_TTYSTOP && 1179 pr->ps_pgrp->pg_jobc == 0) { 1180 mask = 0; 1181 prop = 0; 1182 goto out; 1183 } 1184 } 1185 } 1186 1187 /* 1188 * If SIGCONT is default (or ignored) and process is 1189 * asleep, we are finished; the process should not 1190 * be awakened. 1191 */ 1192 if ((prop & SA_CONT) && action == SIG_DFL) { 1193 mask = 0; 1194 goto out; 1195 } 1196 /* 1197 * When a sleeping process receives a stop 1198 * signal, process immediately if possible. 1199 */ 1200 if ((prop & SA_STOP) && action == SIG_DFL) { 1201 /* 1202 * If a child holding parent blocked, 1203 * stopping could cause deadlock. 1204 */ 1205 if (pr->ps_flags & PS_PPWAIT) 1206 goto out; 1207 mask = 0; 1208 pr->ps_xsig = signum; 1209 proc_stop(p, 0); 1210 goto out; 1211 } 1212 /* 1213 * All other (caught or default) signals 1214 * cause the process to run. 1215 * Raise priority to at least PUSER. 1216 */ 1217 if (p->p_usrpri > PUSER) 1218 p->p_usrpri = PUSER; 1219 unsleep(p); 1220 setrunnable(p); 1221 goto out; 1222 /* NOTREACHED */ 1223 1224 case SONPROC: 1225 if (action == SIG_HOLD) 1226 goto out; 1227 1228 /* set siglist before issuing the ast */ 1229 atomic_setbits_int(siglist, mask); 1230 mask = 0; 1231 signotify(p); 1232 /* FALLTHROUGH */ 1233 default: 1234 /* 1235 * SRUN, SIDL, SDEAD do nothing with the signal, 1236 * other than kicking ourselves if we are running. 1237 * It will either never be noticed, or noticed very soon. 1238 */ 1239 goto out; 1240 } 1241 /* NOTREACHED */ 1242 1243 out: 1244 /* finally adjust siglist */ 1245 if (mask) 1246 atomic_setbits_int(siglist, mask); 1247 if (prop & SA_CONT) { 1248 atomic_clearbits_int(siglist, STOPSIGMASK); 1249 } 1250 if (prop & SA_STOP) { 1251 atomic_clearbits_int(siglist, CONTSIGMASK); 1252 atomic_clearbits_int(&pr->ps_flags, PS_CONTINUED); 1253 } 1254 1255 SCHED_UNLOCK(); 1256 if (wakeparent) 1257 wakeup(pr->ps_pptr); 1258 } 1259 1260 /* fill the signal context which should be used by postsig() and issignal() */ 1261 void 1262 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1263 { 1264 struct sigacts *ps = p->p_p->ps_sigacts; 1265 sigset_t mask; 1266 1267 mtx_enter(&p->p_p->ps_mtx); 1268 mask = sigmask(signum); 1269 sctx->sig_action = ps->ps_sigact[signum]; 1270 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1271 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1272 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1273 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1274 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1275 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1276 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1277 mtx_leave(&p->p_p->ps_mtx); 1278 } 1279 1280 /* 1281 * Determine signal that should be delivered to process p, the current 1282 * process, 0 if none. 1283 * 1284 * If the current process has received a signal (should be caught or cause 1285 * termination, should interrupt current syscall), return the signal number. 1286 * Stop signals with default action are processed immediately, then cleared; 1287 * they aren't returned. This is checked after each entry to the system for 1288 * a syscall or trap. The normal call sequence is 1289 * 1290 * while (signum = cursig(curproc, &ctx)) 1291 * postsig(signum, &ctx); 1292 * 1293 * Assumes that if the P_SINTR flag is set, we're holding both the 1294 * kernel and scheduler locks. 1295 */ 1296 int 1297 cursig(struct proc *p, struct sigctx *sctx) 1298 { 1299 struct process *pr = p->p_p; 1300 int signum, mask, prop; 1301 sigset_t ps_siglist; 1302 1303 KASSERT(p == curproc); 1304 1305 for (;;) { 1306 ps_siglist = READ_ONCE(pr->ps_siglist); 1307 membar_consumer(); 1308 mask = SIGPENDING(p); 1309 if (pr->ps_flags & PS_PPWAIT) 1310 mask &= ~STOPSIGMASK; 1311 if (mask == 0) /* no signal to send */ 1312 return (0); 1313 signum = ffs((long)mask); 1314 mask = sigmask(signum); 1315 1316 /* take the signal! */ 1317 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1318 ps_siglist & ~mask) != ps_siglist) { 1319 /* lost race taking the process signal, restart */ 1320 continue; 1321 } 1322 atomic_clearbits_int(&p->p_siglist, mask); 1323 setsigctx(p, signum, sctx); 1324 1325 /* 1326 * We should see pending but ignored signals 1327 * only if PS_TRACED was on when they were posted. 1328 */ 1329 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1330 continue; 1331 1332 /* 1333 * If traced, always stop, and stay stopped until released 1334 * by the debugger. If our parent process is waiting for 1335 * us, don't hang as we could deadlock. 1336 */ 1337 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1338 signum != SIGKILL) { 1339 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1340 pr->ps_xsig = signum; 1341 1342 SCHED_LOCK(); 1343 proc_stop(p, 1); 1344 SCHED_UNLOCK(); 1345 1346 /* 1347 * re-take the signal before releasing 1348 * the other threads. Must check the continue 1349 * conditions below and only take the signal if 1350 * those are not true. 1351 */ 1352 signum = pr->ps_xsig; 1353 mask = sigmask(signum); 1354 setsigctx(p, signum, sctx); 1355 if (!((pr->ps_flags & PS_TRACED) == 0 || 1356 signum == 0 || 1357 (p->p_sigmask & mask) != 0)) { 1358 atomic_clearbits_int(&p->p_siglist, mask); 1359 atomic_clearbits_int(&pr->ps_siglist, mask); 1360 } 1361 1362 single_thread_clear(p, 0); 1363 1364 /* 1365 * If we are no longer being traced, or the parent 1366 * didn't give us a signal, look for more signals. 1367 */ 1368 if ((pr->ps_flags & PS_TRACED) == 0 || 1369 signum == 0) 1370 continue; 1371 1372 /* 1373 * If the new signal is being masked, look for other 1374 * signals. 1375 */ 1376 if ((p->p_sigmask & mask) != 0) 1377 continue; 1378 1379 } 1380 1381 prop = sigprop[signum]; 1382 1383 /* 1384 * Decide whether the signal should be returned. 1385 * Return the signal's number, or fall through 1386 * to clear it from the pending mask. 1387 */ 1388 switch ((long)sctx->sig_action) { 1389 case (long)SIG_DFL: 1390 /* 1391 * Don't take default actions on system processes. 1392 */ 1393 if (pr->ps_pid <= 1) { 1394 #ifdef DIAGNOSTIC 1395 /* 1396 * Are you sure you want to ignore SIGSEGV 1397 * in init? XXX 1398 */ 1399 printf("Process (pid %d) got signal" 1400 " %d\n", pr->ps_pid, signum); 1401 #endif 1402 break; /* == ignore */ 1403 } 1404 /* 1405 * If there is a pending stop signal to process 1406 * with default action, stop here, 1407 * then clear the signal. However, 1408 * if process is member of an orphaned 1409 * process group, ignore tty stop signals. 1410 */ 1411 if (prop & SA_STOP) { 1412 if (pr->ps_flags & PS_TRACED || 1413 (pr->ps_pgrp->pg_jobc == 0 && 1414 prop & SA_TTYSTOP)) 1415 break; /* == ignore */ 1416 pr->ps_xsig = signum; 1417 SCHED_LOCK(); 1418 proc_stop(p, 1); 1419 SCHED_UNLOCK(); 1420 break; 1421 } else if (prop & SA_IGNORE) { 1422 /* 1423 * Except for SIGCONT, shouldn't get here. 1424 * Default action is to ignore; drop it. 1425 */ 1426 break; /* == ignore */ 1427 } else 1428 goto keep; 1429 /* NOTREACHED */ 1430 case (long)SIG_IGN: 1431 /* 1432 * Masking above should prevent us ever trying 1433 * to take action on an ignored signal other 1434 * than SIGCONT, unless process is traced. 1435 */ 1436 if ((prop & SA_CONT) == 0 && 1437 (pr->ps_flags & PS_TRACED) == 0) 1438 printf("%s\n", __func__); 1439 break; /* == ignore */ 1440 default: 1441 /* 1442 * This signal has an action, let 1443 * postsig() process it. 1444 */ 1445 goto keep; 1446 } 1447 } 1448 /* NOTREACHED */ 1449 1450 keep: 1451 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1452 return (signum); 1453 } 1454 1455 /* 1456 * Put the argument process into the stopped state and notify the parent 1457 * via wakeup. Signals are handled elsewhere. The process must not be 1458 * on the run queue. 1459 */ 1460 void 1461 proc_stop(struct proc *p, int sw) 1462 { 1463 struct process *pr = p->p_p; 1464 1465 #ifdef MULTIPROCESSOR 1466 SCHED_ASSERT_LOCKED(); 1467 #endif 1468 /* do not stop exiting procs */ 1469 if (ISSET(p->p_flag, P_WEXIT)) 1470 return; 1471 1472 p->p_stat = SSTOP; 1473 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1474 atomic_setbits_int(&pr->ps_flags, PS_STOPPING); 1475 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1476 /* 1477 * We need this soft interrupt to be handled fast. 1478 * Extra calls to softclock don't hurt. 1479 */ 1480 softintr_schedule(proc_stop_si); 1481 if (sw) 1482 mi_switch(); 1483 } 1484 1485 /* 1486 * Called from a soft interrupt to send signals to the parents of stopped 1487 * processes. 1488 * We can't do this in proc_stop because it's called with nasty locks held 1489 * and we would need recursive scheduler lock to deal with that. 1490 */ 1491 void 1492 proc_stop_sweep(void *v) 1493 { 1494 struct process *pr; 1495 1496 LIST_FOREACH(pr, &allprocess, ps_list) { 1497 if ((pr->ps_flags & PS_STOPPING) == 0) 1498 continue; 1499 atomic_clearbits_int(&pr->ps_flags, PS_STOPPING); 1500 1501 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1502 prsignal(pr->ps_pptr, SIGCHLD); 1503 wakeup(pr->ps_pptr); 1504 } 1505 } 1506 1507 /* 1508 * Take the action for the specified signal 1509 * from the current set of pending signals. 1510 */ 1511 void 1512 postsig(struct proc *p, int signum, struct sigctx *sctx) 1513 { 1514 u_long trapno; 1515 int mask, returnmask; 1516 siginfo_t si; 1517 union sigval sigval; 1518 int code; 1519 1520 KASSERT(signum != 0); 1521 1522 mask = sigmask(signum); 1523 atomic_clearbits_int(&p->p_siglist, mask); 1524 sigval.sival_ptr = NULL; 1525 1526 if (p->p_sisig != signum) { 1527 trapno = 0; 1528 code = SI_USER; 1529 sigval.sival_ptr = NULL; 1530 } else { 1531 trapno = p->p_sitrapno; 1532 code = p->p_sicode; 1533 sigval = p->p_sigval; 1534 } 1535 initsiginfo(&si, signum, trapno, code, sigval); 1536 1537 #ifdef KTRACE 1538 if (KTRPOINT(p, KTR_PSIG)) { 1539 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1540 p->p_oldmask : p->p_sigmask, code, &si); 1541 } 1542 #endif 1543 if (sctx->sig_action == SIG_DFL) { 1544 /* 1545 * Default action, where the default is to kill 1546 * the process. (Other cases were ignored above.) 1547 */ 1548 KERNEL_LOCK(); 1549 sigexit(p, signum); 1550 /* NOTREACHED */ 1551 } else { 1552 /* 1553 * If we get here, the signal must be caught. 1554 */ 1555 #ifdef DIAGNOSTIC 1556 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1557 panic("postsig action"); 1558 #endif 1559 /* 1560 * Set the new mask value and also defer further 1561 * occurrences of this signal. 1562 * 1563 * Special case: user has done a sigpause. Here the 1564 * current mask is not of interest, but rather the 1565 * mask from before the sigpause is what we want 1566 * restored after the signal processing is completed. 1567 */ 1568 if (p->p_flag & P_SIGSUSPEND) { 1569 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1570 returnmask = p->p_oldmask; 1571 } else { 1572 returnmask = p->p_sigmask; 1573 } 1574 if (p->p_sisig == signum) { 1575 p->p_sisig = 0; 1576 p->p_sitrapno = 0; 1577 p->p_sicode = SI_USER; 1578 p->p_sigval.sival_ptr = NULL; 1579 } 1580 1581 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1582 sctx->sig_info, sctx->sig_onstack)) { 1583 KERNEL_LOCK(); 1584 sigexit(p, SIGILL); 1585 /* NOTREACHED */ 1586 } 1587 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1588 } 1589 } 1590 1591 /* 1592 * Force the current process to exit with the specified signal, dumping core 1593 * if appropriate. We bypass the normal tests for masked and caught signals, 1594 * allowing unrecoverable failures to terminate the process without changing 1595 * signal state. Mark the accounting record with the signal termination. 1596 * If dumping core, save the signal number for the debugger. Calls exit and 1597 * does not return. 1598 */ 1599 void 1600 sigexit(struct proc *p, int signum) 1601 { 1602 /* Mark process as going away */ 1603 atomic_setbits_int(&p->p_flag, P_WEXIT); 1604 1605 p->p_p->ps_acflag |= AXSIG; 1606 if (sigprop[signum] & SA_CORE) { 1607 p->p_sisig = signum; 1608 1609 /* if there are other threads, pause them */ 1610 if (P_HASSIBLING(p)) 1611 single_thread_set(p, SINGLE_UNWIND); 1612 1613 if (coredump(p) == 0) 1614 signum |= WCOREFLAG; 1615 } 1616 exit1(p, 0, signum, EXIT_NORMAL); 1617 /* NOTREACHED */ 1618 } 1619 1620 /* 1621 * Send uncatchable SIGABRT for coredump. 1622 */ 1623 void 1624 sigabort(struct proc *p) 1625 { 1626 struct sigaction sa; 1627 1628 KASSERT(p == curproc || panicstr || db_active); 1629 1630 memset(&sa, 0, sizeof sa); 1631 sa.sa_handler = SIG_DFL; 1632 setsigvec(p, SIGABRT, &sa); 1633 CLR(p->p_sigmask, sigmask(SIGABRT)); 1634 psignal(p, SIGABRT); 1635 } 1636 1637 /* 1638 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1639 * thread, and 0 otherwise. 1640 */ 1641 int 1642 sigismasked(struct proc *p, int sig) 1643 { 1644 struct process *pr = p->p_p; 1645 int rv; 1646 1647 KASSERT(p == curproc); 1648 1649 mtx_enter(&pr->ps_mtx); 1650 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1651 (p->p_sigmask & sigmask(sig)); 1652 mtx_leave(&pr->ps_mtx); 1653 1654 return !!rv; 1655 } 1656 1657 struct coredump_iostate { 1658 struct proc *io_proc; 1659 struct vnode *io_vp; 1660 struct ucred *io_cred; 1661 off_t io_offset; 1662 }; 1663 1664 /* 1665 * Dump core, into a file named "progname.core", unless the process was 1666 * setuid/setgid. 1667 */ 1668 int 1669 coredump(struct proc *p) 1670 { 1671 #ifdef SMALL_KERNEL 1672 return EPERM; 1673 #else 1674 struct process *pr = p->p_p; 1675 struct vnode *vp; 1676 struct ucred *cred = p->p_ucred; 1677 struct vmspace *vm = p->p_vmspace; 1678 struct nameidata nd; 1679 struct vattr vattr; 1680 struct coredump_iostate io; 1681 int error, len, incrash = 0; 1682 char *name; 1683 const char *dir = "/var/crash"; 1684 1685 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1686 1687 #ifdef PMAP_CHECK_COPYIN 1688 /* disable copyin checks, so we can write out text sections if needed */ 1689 p->p_vmspace->vm_map.check_copyin_count = 0; 1690 #endif 1691 1692 /* Don't dump if will exceed file size limit. */ 1693 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1694 return (EFBIG); 1695 1696 name = pool_get(&namei_pool, PR_WAITOK); 1697 1698 /* 1699 * If the process has inconsistent uids, nosuidcoredump 1700 * determines coredump placement policy. 1701 */ 1702 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1703 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1704 if (nosuidcoredump == 3) { 1705 /* 1706 * If the program directory does not exist, dumps of 1707 * that core will silently fail. 1708 */ 1709 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1710 dir, pr->ps_comm, pr->ps_pid); 1711 incrash = KERNELPATH; 1712 } else if (nosuidcoredump == 2) { 1713 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1714 dir, pr->ps_comm); 1715 incrash = KERNELPATH; 1716 } else { 1717 pool_put(&namei_pool, name); 1718 return (EPERM); 1719 } 1720 } else 1721 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1722 1723 if (len >= MAXPATHLEN) { 1724 pool_put(&namei_pool, name); 1725 return (EACCES); 1726 } 1727 1728 /* 1729 * Control the UID used to write out. The normal case uses 1730 * the real UID. If the sugid case is going to write into the 1731 * controlled directory, we do so as root. 1732 */ 1733 if (incrash == 0) { 1734 cred = crdup(cred); 1735 cred->cr_uid = cred->cr_ruid; 1736 cred->cr_gid = cred->cr_rgid; 1737 } else { 1738 if (p->p_fd->fd_rdir) { 1739 vrele(p->p_fd->fd_rdir); 1740 p->p_fd->fd_rdir = NULL; 1741 } 1742 p->p_ucred = crdup(p->p_ucred); 1743 crfree(cred); 1744 cred = p->p_ucred; 1745 crhold(cred); 1746 cred->cr_uid = 0; 1747 cred->cr_gid = 0; 1748 } 1749 1750 /* incrash should be 0 or KERNELPATH only */ 1751 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1752 1753 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1754 S_IRUSR | S_IWUSR); 1755 1756 if (error) 1757 goto out; 1758 1759 /* 1760 * Don't dump to non-regular files, files with links, or files 1761 * owned by someone else. 1762 */ 1763 vp = nd.ni_vp; 1764 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1765 VOP_UNLOCK(vp); 1766 vn_close(vp, FWRITE, cred, p); 1767 goto out; 1768 } 1769 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1770 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1771 vattr.va_uid != cred->cr_uid) { 1772 error = EACCES; 1773 VOP_UNLOCK(vp); 1774 vn_close(vp, FWRITE, cred, p); 1775 goto out; 1776 } 1777 VATTR_NULL(&vattr); 1778 vattr.va_size = 0; 1779 VOP_SETATTR(vp, &vattr, cred, p); 1780 pr->ps_acflag |= ACORE; 1781 1782 io.io_proc = p; 1783 io.io_vp = vp; 1784 io.io_cred = cred; 1785 io.io_offset = 0; 1786 VOP_UNLOCK(vp); 1787 vref(vp); 1788 error = vn_close(vp, FWRITE, cred, p); 1789 if (error == 0) 1790 error = coredump_elf(p, &io); 1791 vrele(vp); 1792 out: 1793 crfree(cred); 1794 pool_put(&namei_pool, name); 1795 return (error); 1796 #endif 1797 } 1798 1799 #ifndef SMALL_KERNEL 1800 int 1801 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1802 int isvnode) 1803 { 1804 struct coredump_iostate *io = cookie; 1805 off_t coffset = 0; 1806 size_t csize; 1807 int chunk, error; 1808 1809 csize = len; 1810 do { 1811 if (sigmask(SIGKILL) & 1812 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1813 return (EINTR); 1814 1815 /* Rest of the loop sleeps with lock held, so... */ 1816 yield(); 1817 1818 chunk = MIN(csize, MAXPHYS); 1819 error = vn_rdwr(UIO_WRITE, io->io_vp, 1820 (caddr_t)data + coffset, chunk, 1821 io->io_offset + coffset, segflg, 1822 IO_UNIT, io->io_cred, NULL, io->io_proc); 1823 if (error && (error != EFAULT || !isvnode)) { 1824 struct process *pr = io->io_proc->p_p; 1825 1826 if (error == ENOSPC) 1827 log(LOG_ERR, 1828 "coredump of %s(%d) failed, filesystem full\n", 1829 pr->ps_comm, pr->ps_pid); 1830 else 1831 log(LOG_ERR, 1832 "coredump of %s(%d), write failed: errno %d\n", 1833 pr->ps_comm, pr->ps_pid, error); 1834 return (error); 1835 } 1836 1837 coffset += chunk; 1838 csize -= chunk; 1839 } while (csize > 0); 1840 1841 io->io_offset += len; 1842 return (0); 1843 } 1844 1845 void 1846 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1847 { 1848 struct coredump_iostate *io = cookie; 1849 1850 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1851 } 1852 1853 #endif /* !SMALL_KERNEL */ 1854 1855 /* 1856 * Nonexistent system call-- signal process (may want to handle it). 1857 * Flag error in case process won't see signal immediately (blocked or ignored). 1858 */ 1859 int 1860 sys_nosys(struct proc *p, void *v, register_t *retval) 1861 { 1862 ptsignal(p, SIGSYS, STHREAD); 1863 return (ENOSYS); 1864 } 1865 1866 int 1867 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1868 { 1869 struct sys___thrsigdivert_args /* { 1870 syscallarg(sigset_t) sigmask; 1871 syscallarg(siginfo_t *) info; 1872 syscallarg(const struct timespec *) timeout; 1873 } */ *uap = v; 1874 struct sigctx ctx; 1875 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1876 siginfo_t si; 1877 uint64_t nsecs = INFSLP; 1878 int timeinvalid = 0; 1879 int error = 0; 1880 1881 memset(&si, 0, sizeof(si)); 1882 1883 if (SCARG(uap, timeout) != NULL) { 1884 struct timespec ts; 1885 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1886 return (error); 1887 #ifdef KTRACE 1888 if (KTRPOINT(p, KTR_STRUCT)) 1889 ktrreltimespec(p, &ts); 1890 #endif 1891 if (!timespecisvalid(&ts)) 1892 timeinvalid = 1; 1893 else 1894 nsecs = TIMESPEC_TO_NSEC(&ts); 1895 } 1896 1897 dosigsuspend(p, p->p_sigmask &~ mask); 1898 for (;;) { 1899 si.si_signo = cursig(p, &ctx); 1900 if (si.si_signo != 0) { 1901 sigset_t smask = sigmask(si.si_signo); 1902 if (smask & mask) { 1903 atomic_clearbits_int(&p->p_siglist, smask); 1904 error = 0; 1905 break; 1906 } 1907 } 1908 1909 /* per-POSIX, delay this error until after the above */ 1910 if (timeinvalid) 1911 error = EINVAL; 1912 /* per-POSIX, return immediately if timeout is zero-valued */ 1913 if (nsecs == 0) 1914 error = EAGAIN; 1915 1916 if (error != 0) 1917 break; 1918 1919 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1920 } 1921 1922 if (error == 0) { 1923 *retval = si.si_signo; 1924 if (SCARG(uap, info) != NULL) { 1925 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1926 #ifdef KTRACE 1927 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1928 ktrsiginfo(p, &si); 1929 #endif 1930 } 1931 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1932 /* 1933 * Restarting is wrong if there's a timeout, as it'll be 1934 * for the same interval again 1935 */ 1936 error = EINTR; 1937 } 1938 1939 return (error); 1940 } 1941 1942 void 1943 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1944 { 1945 memset(si, 0, sizeof(*si)); 1946 1947 si->si_signo = sig; 1948 si->si_code = code; 1949 if (code == SI_USER) { 1950 si->si_value = val; 1951 } else { 1952 switch (sig) { 1953 case SIGSEGV: 1954 case SIGILL: 1955 case SIGBUS: 1956 case SIGFPE: 1957 si->si_addr = val.sival_ptr; 1958 si->si_trapno = trapno; 1959 break; 1960 case SIGXFSZ: 1961 break; 1962 } 1963 } 1964 } 1965 1966 void 1967 userret(struct proc *p) 1968 { 1969 struct sigctx ctx; 1970 int signum; 1971 1972 if (p->p_flag & P_SUSPSINGLE) 1973 single_thread_check(p, 0); 1974 1975 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1976 if (p->p_flag & P_PROFPEND) { 1977 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1978 KERNEL_LOCK(); 1979 psignal(p, SIGPROF); 1980 KERNEL_UNLOCK(); 1981 } 1982 if (p->p_flag & P_ALRMPEND) { 1983 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1984 KERNEL_LOCK(); 1985 psignal(p, SIGVTALRM); 1986 KERNEL_UNLOCK(); 1987 } 1988 1989 if (SIGPENDING(p) != 0) { 1990 while ((signum = cursig(p, &ctx)) != 0) 1991 postsig(p, signum, &ctx); 1992 } 1993 1994 /* 1995 * If P_SIGSUSPEND is still set here, then we still need to restore 1996 * the original sigmask before returning to userspace. Also, this 1997 * might unmask some pending signals, so we need to check a second 1998 * time for signals to post. 1999 */ 2000 if (p->p_flag & P_SIGSUSPEND) { 2001 p->p_sigmask = p->p_oldmask; 2002 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2003 2004 while ((signum = cursig(p, &ctx)) != 0) 2005 postsig(p, signum, &ctx); 2006 } 2007 2008 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2009 2010 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2011 } 2012 2013 int 2014 single_thread_check_locked(struct proc *p, int deep) 2015 { 2016 struct process *pr = p->p_p; 2017 2018 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 2019 2020 if (pr->ps_single == NULL || pr->ps_single == p) 2021 return (0); 2022 2023 do { 2024 /* if we're in deep, we need to unwind to the edge */ 2025 if (deep) { 2026 if (pr->ps_flags & PS_SINGLEUNWIND) 2027 return (ERESTART); 2028 if (pr->ps_flags & PS_SINGLEEXIT) 2029 return (EINTR); 2030 } 2031 2032 if (pr->ps_flags & PS_SINGLEEXIT) { 2033 mtx_leave(&pr->ps_mtx); 2034 KERNEL_LOCK(); 2035 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2036 /* NOTREACHED */ 2037 } 2038 2039 if (--pr->ps_singlecnt == 0) 2040 wakeup(&pr->ps_singlecnt); 2041 2042 /* not exiting and don't need to unwind, so suspend */ 2043 mtx_leave(&pr->ps_mtx); 2044 2045 SCHED_LOCK(); 2046 p->p_stat = SSTOP; 2047 mi_switch(); 2048 SCHED_UNLOCK(); 2049 mtx_enter(&pr->ps_mtx); 2050 } while (pr->ps_single != NULL); 2051 2052 return (0); 2053 } 2054 2055 int 2056 single_thread_check(struct proc *p, int deep) 2057 { 2058 int error; 2059 2060 mtx_enter(&p->p_p->ps_mtx); 2061 error = single_thread_check_locked(p, deep); 2062 mtx_leave(&p->p_p->ps_mtx); 2063 2064 return error; 2065 } 2066 2067 /* 2068 * Stop other threads in the process. The mode controls how and 2069 * where the other threads should stop: 2070 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2071 * single_thread_clear()) 2072 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2073 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2074 * - SINGLE_EXIT: unwind to kernel boundary and exit 2075 */ 2076 int 2077 single_thread_set(struct proc *p, int flags) 2078 { 2079 struct process *pr = p->p_p; 2080 struct proc *q; 2081 int error, mode = flags & SINGLE_MASK; 2082 2083 KASSERT(curproc == p); 2084 2085 mtx_enter(&pr->ps_mtx); 2086 error = single_thread_check_locked(p, flags & SINGLE_DEEP); 2087 if (error) { 2088 mtx_leave(&pr->ps_mtx); 2089 return error; 2090 } 2091 2092 switch (mode) { 2093 case SINGLE_SUSPEND: 2094 break; 2095 case SINGLE_UNWIND: 2096 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2097 break; 2098 case SINGLE_EXIT: 2099 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2100 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2101 break; 2102 #ifdef DIAGNOSTIC 2103 default: 2104 panic("single_thread_mode = %d", mode); 2105 #endif 2106 } 2107 KASSERT((p->p_flag & P_SUSPSINGLE) == 0); 2108 pr->ps_single = p; 2109 pr->ps_singlecnt = pr->ps_threadcnt; 2110 2111 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2112 if (q == p) 2113 continue; 2114 SCHED_LOCK(); 2115 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2116 switch (q->p_stat) { 2117 case SSTOP: 2118 if (mode == SINGLE_EXIT) { 2119 unsleep(q); 2120 setrunnable(q); 2121 } else 2122 --pr->ps_singlecnt; 2123 break; 2124 case SSLEEP: 2125 /* if it's not interruptible, then just have to wait */ 2126 if (q->p_flag & P_SINTR) { 2127 /* merely need to suspend? just stop it */ 2128 if (mode == SINGLE_SUSPEND) { 2129 q->p_stat = SSTOP; 2130 --pr->ps_singlecnt; 2131 break; 2132 } 2133 /* need to unwind or exit, so wake it */ 2134 unsleep(q); 2135 setrunnable(q); 2136 } 2137 break; 2138 case SONPROC: 2139 signotify(q); 2140 break; 2141 case SRUN: 2142 case SIDL: 2143 case SDEAD: 2144 break; 2145 } 2146 SCHED_UNLOCK(); 2147 } 2148 2149 /* count ourselfs out */ 2150 --pr->ps_singlecnt; 2151 mtx_leave(&pr->ps_mtx); 2152 2153 if ((flags & SINGLE_NOWAIT) == 0) 2154 single_thread_wait(pr, 1); 2155 2156 return 0; 2157 } 2158 2159 /* 2160 * Wait for other threads to stop. If recheck is false then the function 2161 * returns non-zero if the caller needs to restart the check else 0 is 2162 * returned. If recheck is true the return value is always 0. 2163 */ 2164 int 2165 single_thread_wait(struct process *pr, int recheck) 2166 { 2167 int wait; 2168 2169 /* wait until they're all suspended */ 2170 mtx_enter(&pr->ps_mtx); 2171 while ((wait = pr->ps_singlecnt > 0)) { 2172 msleep_nsec(&pr->ps_singlecnt, &pr->ps_mtx, PWAIT, "suspend", 2173 INFSLP); 2174 if (!recheck) 2175 break; 2176 } 2177 KASSERT((pr->ps_single->p_flag & P_SUSPSINGLE) == 0); 2178 mtx_leave(&pr->ps_mtx); 2179 2180 return wait; 2181 } 2182 2183 void 2184 single_thread_clear(struct proc *p, int flag) 2185 { 2186 struct process *pr = p->p_p; 2187 struct proc *q; 2188 2189 KASSERT(pr->ps_single == p); 2190 KASSERT(curproc == p); 2191 2192 mtx_enter(&pr->ps_mtx); 2193 pr->ps_single = NULL; 2194 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2195 2196 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2197 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2198 continue; 2199 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2200 2201 /* 2202 * if the thread was only stopped for single threading 2203 * then clearing that either makes it runnable or puts 2204 * it back into some sleep queue 2205 */ 2206 SCHED_LOCK(); 2207 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2208 if (q->p_wchan == NULL) 2209 setrunnable(q); 2210 else { 2211 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2212 q->p_stat = SSLEEP; 2213 } 2214 } 2215 SCHED_UNLOCK(); 2216 } 2217 mtx_leave(&pr->ps_mtx); 2218 } 2219 2220 void 2221 sigio_del(struct sigiolst *rmlist) 2222 { 2223 struct sigio *sigio; 2224 2225 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2226 LIST_REMOVE(sigio, sio_pgsigio); 2227 crfree(sigio->sio_ucred); 2228 free(sigio, M_SIGIO, sizeof(*sigio)); 2229 } 2230 } 2231 2232 void 2233 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2234 { 2235 struct sigio *sigio; 2236 2237 MUTEX_ASSERT_LOCKED(&sigio_lock); 2238 2239 sigio = sir->sir_sigio; 2240 if (sigio != NULL) { 2241 KASSERT(sigio->sio_myref == sir); 2242 sir->sir_sigio = NULL; 2243 2244 if (sigio->sio_pgid > 0) 2245 sigio->sio_proc = NULL; 2246 else 2247 sigio->sio_pgrp = NULL; 2248 LIST_REMOVE(sigio, sio_pgsigio); 2249 2250 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2251 } 2252 } 2253 2254 void 2255 sigio_free(struct sigio_ref *sir) 2256 { 2257 struct sigiolst rmlist; 2258 2259 if (sir->sir_sigio == NULL) 2260 return; 2261 2262 LIST_INIT(&rmlist); 2263 2264 mtx_enter(&sigio_lock); 2265 sigio_unlink(sir, &rmlist); 2266 mtx_leave(&sigio_lock); 2267 2268 sigio_del(&rmlist); 2269 } 2270 2271 void 2272 sigio_freelist(struct sigiolst *sigiolst) 2273 { 2274 struct sigiolst rmlist; 2275 struct sigio *sigio; 2276 2277 if (LIST_EMPTY(sigiolst)) 2278 return; 2279 2280 LIST_INIT(&rmlist); 2281 2282 mtx_enter(&sigio_lock); 2283 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2284 sigio_unlink(sigio->sio_myref, &rmlist); 2285 mtx_leave(&sigio_lock); 2286 2287 sigio_del(&rmlist); 2288 } 2289 2290 int 2291 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2292 { 2293 struct sigiolst rmlist; 2294 struct proc *p = curproc; 2295 struct pgrp *pgrp = NULL; 2296 struct process *pr = NULL; 2297 struct sigio *sigio; 2298 int error; 2299 pid_t pgid = *(int *)data; 2300 2301 if (pgid == 0) { 2302 sigio_free(sir); 2303 return (0); 2304 } 2305 2306 if (cmd == TIOCSPGRP) { 2307 if (pgid < 0) 2308 return (EINVAL); 2309 pgid = -pgid; 2310 } 2311 2312 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2313 sigio->sio_pgid = pgid; 2314 sigio->sio_ucred = crhold(p->p_ucred); 2315 sigio->sio_myref = sir; 2316 2317 LIST_INIT(&rmlist); 2318 2319 /* 2320 * The kernel lock, and not sleeping between prfind()/pgfind() and 2321 * linking of the sigio ensure that the process or process group does 2322 * not disappear unexpectedly. 2323 */ 2324 KERNEL_LOCK(); 2325 mtx_enter(&sigio_lock); 2326 2327 if (pgid > 0) { 2328 pr = prfind(pgid); 2329 if (pr == NULL) { 2330 error = ESRCH; 2331 goto fail; 2332 } 2333 2334 /* 2335 * Policy - Don't allow a process to FSETOWN a process 2336 * in another session. 2337 * 2338 * Remove this test to allow maximum flexibility or 2339 * restrict FSETOWN to the current process or process 2340 * group for maximum safety. 2341 */ 2342 if (pr->ps_session != p->p_p->ps_session) { 2343 error = EPERM; 2344 goto fail; 2345 } 2346 2347 if ((pr->ps_flags & PS_EXITING) != 0) { 2348 error = ESRCH; 2349 goto fail; 2350 } 2351 } else /* if (pgid < 0) */ { 2352 pgrp = pgfind(-pgid); 2353 if (pgrp == NULL) { 2354 error = ESRCH; 2355 goto fail; 2356 } 2357 2358 /* 2359 * Policy - Don't allow a process to FSETOWN a process 2360 * in another session. 2361 * 2362 * Remove this test to allow maximum flexibility or 2363 * restrict FSETOWN to the current process or process 2364 * group for maximum safety. 2365 */ 2366 if (pgrp->pg_session != p->p_p->ps_session) { 2367 error = EPERM; 2368 goto fail; 2369 } 2370 } 2371 2372 if (pgid > 0) { 2373 sigio->sio_proc = pr; 2374 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2375 } else { 2376 sigio->sio_pgrp = pgrp; 2377 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2378 } 2379 2380 sigio_unlink(sir, &rmlist); 2381 sir->sir_sigio = sigio; 2382 2383 mtx_leave(&sigio_lock); 2384 KERNEL_UNLOCK(); 2385 2386 sigio_del(&rmlist); 2387 2388 return (0); 2389 2390 fail: 2391 mtx_leave(&sigio_lock); 2392 KERNEL_UNLOCK(); 2393 2394 crfree(sigio->sio_ucred); 2395 free(sigio, M_SIGIO, sizeof(*sigio)); 2396 2397 return (error); 2398 } 2399 2400 void 2401 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2402 { 2403 struct sigio *sigio; 2404 pid_t pgid = 0; 2405 2406 mtx_enter(&sigio_lock); 2407 sigio = sir->sir_sigio; 2408 if (sigio != NULL) 2409 pgid = sigio->sio_pgid; 2410 mtx_leave(&sigio_lock); 2411 2412 if (cmd == TIOCGPGRP) 2413 pgid = -pgid; 2414 2415 *(int *)data = pgid; 2416 } 2417 2418 void 2419 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2420 { 2421 struct sigiolst rmlist; 2422 struct sigio *newsigio, *sigio; 2423 2424 sigio_free(dst); 2425 2426 if (src->sir_sigio == NULL) 2427 return; 2428 2429 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2430 LIST_INIT(&rmlist); 2431 2432 mtx_enter(&sigio_lock); 2433 2434 sigio = src->sir_sigio; 2435 if (sigio == NULL) { 2436 mtx_leave(&sigio_lock); 2437 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2438 return; 2439 } 2440 2441 newsigio->sio_pgid = sigio->sio_pgid; 2442 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2443 newsigio->sio_myref = dst; 2444 if (newsigio->sio_pgid > 0) { 2445 newsigio->sio_proc = sigio->sio_proc; 2446 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2447 sio_pgsigio); 2448 } else { 2449 newsigio->sio_pgrp = sigio->sio_pgrp; 2450 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2451 sio_pgsigio); 2452 } 2453 2454 sigio_unlink(dst, &rmlist); 2455 dst->sir_sigio = newsigio; 2456 2457 mtx_leave(&sigio_lock); 2458 2459 sigio_del(&rmlist); 2460 } 2461