1 /* $OpenBSD: kern_sig.c,v 1.342 2024/10/15 13:49:26 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 pr->ps_xsig = 0; 844 if ((p->p_flag & P_TRACESINGLE) == 0) 845 single_thread_clear(p, 0); 846 atomic_clearbits_int(&p->p_flag, P_TRACESINGLE); 847 848 /* 849 * If we are no longer being traced, or the parent 850 * didn't give us a signal, skip sending the signal. 851 */ 852 if ((pr->ps_flags & PS_TRACED) == 0 || 853 signum == 0) 854 return; 855 856 /* update signal info */ 857 p->p_sisig = signum; 858 mask = sigmask(signum); 859 } 860 861 /* 862 * Signals like SIGBUS and SIGSEGV should not, when 863 * generated by the kernel, be ignorable or blockable. 864 * If it is and we're not being traced, then just kill 865 * the process. 866 * After vfs_shutdown(9), init(8) cannot receive signals 867 * because new code pages of the signal handler cannot be 868 * mapped from halted storage. init(8) may not die or the 869 * kernel panics. Better loop between signal handler and 870 * page fault trap until the machine is halted. 871 */ 872 if ((pr->ps_flags & PS_TRACED) == 0 && 873 (sigprop[signum] & SA_KILL) && 874 ((p->p_sigmask & mask) || ctx.sig_ignore) && 875 pr->ps_pid != 1) { 876 KERNEL_LOCK(); 877 sigexit(p, signum); 878 /* NOTREACHED */ 879 } 880 KERNEL_LOCK(); 881 ptsignal(p, signum, STHREAD); 882 KERNEL_UNLOCK(); 883 } 884 } 885 886 /* 887 * Send the signal to the process. If the signal has an action, the action 888 * is usually performed by the target process rather than the caller; we add 889 * the signal to the set of pending signals for the process. 890 * 891 * Exceptions: 892 * o When a stop signal is sent to a sleeping process that takes the 893 * default action, the process is stopped without awakening it. 894 * o SIGCONT restarts stopped processes (or puts them back to sleep) 895 * regardless of the signal action (eg, blocked or ignored). 896 * 897 * Other ignored signals are discarded immediately. 898 */ 899 void 900 psignal(struct proc *p, int signum) 901 { 902 ptsignal(p, signum, SPROCESS); 903 } 904 905 void 906 prsignal(struct process *pr, int signum) 907 { 908 /* Ignore signal if the target process is exiting */ 909 if (pr->ps_flags & PS_EXITING) { 910 return; 911 } 912 ptsignal(TAILQ_FIRST(&pr->ps_threads), signum, SPROCESS); 913 } 914 915 /* 916 * type = SPROCESS process signal, can be diverted (sigwait()) 917 * type = STHREAD thread signal, but should be propagated if unhandled 918 * type = SPROPAGATED propagated to this thread, so don't propagate again 919 */ 920 void 921 ptsignal(struct proc *p, int signum, enum signal_type type) 922 { 923 int prop; 924 sig_t action, altaction = SIG_DFL; 925 sigset_t mask, sigmask; 926 int *siglist; 927 struct process *pr = p->p_p; 928 struct proc *q; 929 int wakeparent = 0; 930 931 KERNEL_ASSERT_LOCKED(); 932 933 #ifdef DIAGNOSTIC 934 if ((u_int)signum >= NSIG || signum == 0) 935 panic("psignal signal number"); 936 #endif 937 938 /* Ignore signal if the target process is exiting */ 939 if (pr->ps_flags & PS_EXITING) 940 return; 941 942 mask = sigmask(signum); 943 sigmask = READ_ONCE(p->p_sigmask); 944 945 if (type == SPROCESS) { 946 sigset_t tmpmask; 947 948 /* Accept SIGKILL to coredumping processes */ 949 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 950 atomic_setbits_int(&pr->ps_siglist, mask); 951 return; 952 } 953 954 /* 955 * If the current thread can process the signal 956 * immediately (it's unblocked) then have it take it. 957 */ 958 q = curproc; 959 tmpmask = READ_ONCE(q->p_sigmask); 960 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 961 (tmpmask & mask) == 0) { 962 p = q; 963 sigmask = tmpmask; 964 } else { 965 /* 966 * A process-wide signal can be diverted to a 967 * different thread that's in sigwait() for this 968 * signal. If there isn't such a thread, then 969 * pick a thread that doesn't have it blocked so 970 * that the stop/kill consideration isn't 971 * delayed. Otherwise, mark it pending on the 972 * main thread. 973 */ 974 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 975 976 /* ignore exiting threads */ 977 if (q->p_flag & P_WEXIT) 978 continue; 979 980 /* skip threads that have the signal blocked */ 981 tmpmask = READ_ONCE(q->p_sigmask); 982 if ((tmpmask & mask) != 0) 983 continue; 984 985 /* okay, could send to this thread */ 986 p = q; 987 sigmask = tmpmask; 988 989 /* 990 * sigsuspend, sigwait, ppoll/pselect, etc? 991 * Definitely go to this thread, as it's 992 * already blocked in the kernel. 993 */ 994 if (q->p_flag & P_SIGSUSPEND) 995 break; 996 } 997 } 998 } 999 1000 if (type != SPROPAGATED) 1001 knote(&pr->ps_klist, NOTE_SIGNAL | signum); 1002 1003 prop = sigprop[signum]; 1004 1005 /* 1006 * If proc is traced, always give parent a chance. 1007 */ 1008 if (pr->ps_flags & PS_TRACED) { 1009 action = SIG_DFL; 1010 } else { 1011 sigset_t sigcatch, sigignore; 1012 1013 /* 1014 * If the signal is being ignored, 1015 * then we forget about it immediately. 1016 * (Note: we don't set SIGCONT in ps_sigignore, 1017 * and if it is set to SIG_IGN, 1018 * action will be SIG_DFL here.) 1019 */ 1020 mtx_enter(&pr->ps_mtx); 1021 sigignore = pr->ps_sigacts->ps_sigignore; 1022 sigcatch = pr->ps_sigacts->ps_sigcatch; 1023 mtx_leave(&pr->ps_mtx); 1024 1025 if (sigignore & mask) 1026 return; 1027 if (sigmask & mask) { 1028 action = SIG_HOLD; 1029 if (sigcatch & mask) 1030 altaction = SIG_CATCH; 1031 } else if (sigcatch & mask) { 1032 action = SIG_CATCH; 1033 } else { 1034 action = SIG_DFL; 1035 1036 if (prop & SA_KILL && pr->ps_nice > NZERO) 1037 pr->ps_nice = NZERO; 1038 1039 /* 1040 * If sending a tty stop signal to a member of an 1041 * orphaned process group, discard the signal here if 1042 * the action is default; don't stop the process below 1043 * if sleeping, and don't clear any pending SIGCONT. 1044 */ 1045 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1046 return; 1047 } 1048 } 1049 /* 1050 * If delivered to process, mark as pending there. Continue and stop 1051 * signals will be propagated to all threads. So they are always 1052 * marked at thread level. 1053 */ 1054 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1055 if (prop & (SA_CONT | SA_STOP)) 1056 siglist = &p->p_siglist; 1057 1058 /* 1059 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1060 */ 1061 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1062 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1063 if (q != p) 1064 ptsignal(q, signum, SPROPAGATED); 1065 1066 SCHED_LOCK(); 1067 1068 switch (p->p_stat) { 1069 1070 case SSTOP: 1071 /* 1072 * If traced process is already stopped, 1073 * then no further action is necessary. 1074 */ 1075 if (pr->ps_flags & PS_TRACED) 1076 goto out; 1077 1078 /* 1079 * Kill signal always sets processes running. 1080 */ 1081 if (signum == SIGKILL) { 1082 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1083 /* Raise priority to at least PUSER. */ 1084 if (p->p_usrpri > PUSER) 1085 p->p_usrpri = PUSER; 1086 unsleep(p); 1087 setrunnable(p); 1088 goto out; 1089 } 1090 1091 if (prop & SA_CONT) { 1092 /* 1093 * If SIGCONT is default (or ignored), we continue the 1094 * process but don't leave the signal in p_siglist, as 1095 * it has no further action. If SIGCONT is held, we 1096 * continue the process and leave the signal in 1097 * p_siglist. If the process catches SIGCONT, let it 1098 * handle the signal itself. If it isn't waiting on 1099 * an event, then it goes back to run state. 1100 * Otherwise, process goes back to sleep state. 1101 */ 1102 atomic_setbits_int(&pr->ps_flags, PS_CONTINUED); 1103 atomic_clearbits_int(&pr->ps_flags, 1104 PS_WAITED | PS_STOPPED); 1105 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1106 wakeparent = 1; 1107 if (action == SIG_DFL) 1108 mask = 0; 1109 if (action == SIG_CATCH) { 1110 /* Raise priority to at least PUSER. */ 1111 if (p->p_usrpri > PUSER) 1112 p->p_usrpri = PUSER; 1113 unsleep(p); 1114 setrunnable(p); 1115 goto out; 1116 } 1117 if (p->p_wchan == NULL) { 1118 unsleep(p); 1119 setrunnable(p); 1120 goto out; 1121 } 1122 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1123 p->p_stat = SSLEEP; 1124 goto out; 1125 } 1126 1127 /* 1128 * Defer further processing for signals which are held, 1129 * except that stopped processes must be continued by SIGCONT. 1130 */ 1131 if (action == SIG_HOLD) 1132 goto out; 1133 1134 if (prop & SA_STOP) { 1135 /* 1136 * Already stopped, don't need to stop again. 1137 * (If we did the shell could get confused.) 1138 */ 1139 mask = 0; 1140 goto out; 1141 } 1142 1143 /* 1144 * If process is sleeping interruptibly, then simulate a 1145 * wakeup so that when it is continued, it will be made 1146 * runnable and can look at the signal. But don't make 1147 * the process runnable, leave it stopped. 1148 */ 1149 if (p->p_flag & P_SINTR) 1150 unsleep(p); 1151 goto out; 1152 1153 case SSLEEP: 1154 /* 1155 * If process is sleeping uninterruptibly 1156 * we can't interrupt the sleep... the signal will 1157 * be noticed when the process returns through 1158 * trap() or syscall(). 1159 */ 1160 if ((p->p_flag & P_SINTR) == 0) 1161 goto out; 1162 /* 1163 * Process is sleeping and traced... make it runnable 1164 * so it can discover the signal in cursig() and stop 1165 * for the parent. 1166 */ 1167 if (pr->ps_flags & PS_TRACED) { 1168 unsleep(p); 1169 setrunnable(p); 1170 goto out; 1171 } 1172 1173 /* 1174 * Recheck sigmask before waking up the process, 1175 * there is a chance that while sending the signal 1176 * the process changed sigmask and went to sleep. 1177 */ 1178 sigmask = READ_ONCE(p->p_sigmask); 1179 if (sigmask & mask) 1180 goto out; 1181 else if (action == SIG_HOLD) { 1182 /* signal got unmasked, get proper action */ 1183 action = altaction; 1184 1185 if (action == SIG_DFL) { 1186 if (prop & SA_KILL && pr->ps_nice > NZERO) 1187 pr->ps_nice = NZERO; 1188 1189 /* 1190 * Discard tty stop signals sent to an 1191 * orphaned process group, see above. 1192 */ 1193 if (prop & SA_TTYSTOP && 1194 pr->ps_pgrp->pg_jobc == 0) { 1195 mask = 0; 1196 prop = 0; 1197 goto out; 1198 } 1199 } 1200 } 1201 1202 /* 1203 * If SIGCONT is default (or ignored) and process is 1204 * asleep, we are finished; the process should not 1205 * be awakened. 1206 */ 1207 if ((prop & SA_CONT) && action == SIG_DFL) { 1208 mask = 0; 1209 goto out; 1210 } 1211 /* 1212 * When a sleeping process receives a stop 1213 * signal, process immediately if possible. 1214 */ 1215 if ((prop & SA_STOP) && action == SIG_DFL) { 1216 /* 1217 * If a child holding parent blocked, 1218 * stopping could cause deadlock. 1219 */ 1220 if (pr->ps_flags & PS_PPWAIT) 1221 goto out; 1222 mask = 0; 1223 pr->ps_xsig = signum; 1224 proc_stop(p, 0); 1225 goto out; 1226 } 1227 /* 1228 * All other (caught or default) signals 1229 * cause the process to run. 1230 * Raise priority to at least PUSER. 1231 */ 1232 if (p->p_usrpri > PUSER) 1233 p->p_usrpri = PUSER; 1234 unsleep(p); 1235 setrunnable(p); 1236 goto out; 1237 /* NOTREACHED */ 1238 1239 case SONPROC: 1240 if (action == SIG_HOLD) 1241 goto out; 1242 1243 /* set siglist before issuing the ast */ 1244 atomic_setbits_int(siglist, mask); 1245 mask = 0; 1246 signotify(p); 1247 /* FALLTHROUGH */ 1248 default: 1249 /* 1250 * SRUN, SIDL, SDEAD do nothing with the signal, 1251 * other than kicking ourselves if we are running. 1252 * It will either never be noticed, or noticed very soon. 1253 */ 1254 goto out; 1255 } 1256 /* NOTREACHED */ 1257 1258 out: 1259 /* finally adjust siglist */ 1260 if (mask) 1261 atomic_setbits_int(siglist, mask); 1262 if (prop & SA_CONT) { 1263 atomic_clearbits_int(siglist, STOPSIGMASK); 1264 } 1265 if (prop & SA_STOP) { 1266 atomic_clearbits_int(siglist, CONTSIGMASK); 1267 atomic_clearbits_int(&pr->ps_flags, PS_CONTINUED); 1268 } 1269 1270 SCHED_UNLOCK(); 1271 if (wakeparent) 1272 wakeup(pr->ps_pptr); 1273 } 1274 1275 /* fill the signal context which should be used by postsig() and issignal() */ 1276 void 1277 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1278 { 1279 struct sigacts *ps = p->p_p->ps_sigacts; 1280 sigset_t mask; 1281 1282 mtx_enter(&p->p_p->ps_mtx); 1283 mask = sigmask(signum); 1284 sctx->sig_action = ps->ps_sigact[signum]; 1285 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1286 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1287 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1288 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1289 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1290 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1291 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1292 mtx_leave(&p->p_p->ps_mtx); 1293 } 1294 1295 /* 1296 * Determine signal that should be delivered to process p, the current 1297 * process, 0 if none. 1298 * 1299 * If the current process has received a signal (should be caught or cause 1300 * termination, should interrupt current syscall), return the signal number. 1301 * Stop signals with default action are processed immediately, then cleared; 1302 * they aren't returned. This is checked after each entry to the system for 1303 * a syscall or trap. The normal call sequence is 1304 * 1305 * while (signum = cursig(curproc, &ctx)) 1306 * postsig(signum, &ctx); 1307 * 1308 * Assumes that if the P_SINTR flag is set, we're holding both the 1309 * kernel and scheduler locks. 1310 */ 1311 int 1312 cursig(struct proc *p, struct sigctx *sctx) 1313 { 1314 struct process *pr = p->p_p; 1315 int signum, mask, prop; 1316 sigset_t ps_siglist; 1317 1318 KASSERT(p == curproc); 1319 1320 for (;;) { 1321 ps_siglist = READ_ONCE(pr->ps_siglist); 1322 membar_consumer(); 1323 mask = SIGPENDING(p); 1324 if (pr->ps_flags & PS_PPWAIT) 1325 mask &= ~STOPSIGMASK; 1326 if (mask == 0) /* no signal to send */ 1327 return (0); 1328 signum = ffs((long)mask); 1329 mask = sigmask(signum); 1330 1331 /* take the signal! */ 1332 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1333 ps_siglist & ~mask) != ps_siglist) { 1334 /* lost race taking the process signal, restart */ 1335 continue; 1336 } 1337 atomic_clearbits_int(&p->p_siglist, mask); 1338 setsigctx(p, signum, sctx); 1339 1340 /* 1341 * We should see pending but ignored signals 1342 * only if PS_TRACED was on when they were posted. 1343 */ 1344 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1345 continue; 1346 1347 /* 1348 * If traced, always stop, and stay stopped until released 1349 * by the debugger. If our parent process is waiting for 1350 * us, don't hang as we could deadlock. 1351 */ 1352 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1353 signum != SIGKILL) { 1354 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1355 pr->ps_xsig = signum; 1356 1357 SCHED_LOCK(); 1358 proc_stop(p, 1); 1359 SCHED_UNLOCK(); 1360 1361 /* 1362 * re-take the signal before releasing 1363 * the other threads. Must check the continue 1364 * conditions below and only take the signal if 1365 * those are not true. 1366 */ 1367 signum = pr->ps_xsig; 1368 pr->ps_xsig = 0; 1369 mask = sigmask(signum); 1370 setsigctx(p, signum, sctx); 1371 if (!((pr->ps_flags & PS_TRACED) == 0 || 1372 signum == 0 || 1373 (p->p_sigmask & mask) != 0)) { 1374 atomic_clearbits_int(&p->p_siglist, mask); 1375 atomic_clearbits_int(&pr->ps_siglist, mask); 1376 } 1377 1378 if ((p->p_flag & P_TRACESINGLE) == 0) 1379 single_thread_clear(p, 0); 1380 atomic_clearbits_int(&p->p_flag, P_TRACESINGLE); 1381 1382 /* 1383 * If we are no longer being traced, or the parent 1384 * didn't give us a signal, look for more signals. 1385 */ 1386 if ((pr->ps_flags & PS_TRACED) == 0 || 1387 signum == 0) 1388 continue; 1389 1390 /* 1391 * If the new signal is being masked, look for other 1392 * signals. 1393 */ 1394 if ((p->p_sigmask & mask) != 0) 1395 continue; 1396 1397 } 1398 1399 prop = sigprop[signum]; 1400 1401 /* 1402 * Decide whether the signal should be returned. 1403 * Return the signal's number, or fall through 1404 * to clear it from the pending mask. 1405 */ 1406 switch ((long)sctx->sig_action) { 1407 case (long)SIG_DFL: 1408 /* 1409 * Don't take default actions on system processes. 1410 */ 1411 if (pr->ps_pid <= 1) { 1412 #ifdef DIAGNOSTIC 1413 /* 1414 * Are you sure you want to ignore SIGSEGV 1415 * in init? XXX 1416 */ 1417 printf("Process (pid %d) got signal" 1418 " %d\n", pr->ps_pid, signum); 1419 #endif 1420 break; /* == ignore */ 1421 } 1422 /* 1423 * If there is a pending stop signal to process 1424 * with default action, stop here, 1425 * then clear the signal. However, 1426 * if process is member of an orphaned 1427 * process group, ignore tty stop signals. 1428 */ 1429 if (prop & SA_STOP) { 1430 if (pr->ps_flags & PS_TRACED || 1431 (pr->ps_pgrp->pg_jobc == 0 && 1432 prop & SA_TTYSTOP)) 1433 break; /* == ignore */ 1434 pr->ps_xsig = signum; 1435 SCHED_LOCK(); 1436 proc_stop(p, 1); 1437 SCHED_UNLOCK(); 1438 break; 1439 } else if (prop & SA_IGNORE) { 1440 /* 1441 * Except for SIGCONT, shouldn't get here. 1442 * Default action is to ignore; drop it. 1443 */ 1444 break; /* == ignore */ 1445 } else 1446 goto keep; 1447 /* NOTREACHED */ 1448 case (long)SIG_IGN: 1449 /* 1450 * Masking above should prevent us ever trying 1451 * to take action on an ignored signal other 1452 * than SIGCONT, unless process is traced. 1453 */ 1454 if ((prop & SA_CONT) == 0 && 1455 (pr->ps_flags & PS_TRACED) == 0) 1456 printf("%s\n", __func__); 1457 break; /* == ignore */ 1458 default: 1459 /* 1460 * This signal has an action, let 1461 * postsig() process it. 1462 */ 1463 goto keep; 1464 } 1465 } 1466 /* NOTREACHED */ 1467 1468 keep: 1469 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1470 return (signum); 1471 } 1472 1473 /* 1474 * Put the argument process into the stopped state and notify the parent 1475 * via wakeup. Signals are handled elsewhere. The process must not be 1476 * on the run queue. 1477 */ 1478 void 1479 proc_stop(struct proc *p, int sw) 1480 { 1481 struct process *pr = p->p_p; 1482 1483 #ifdef MULTIPROCESSOR 1484 SCHED_ASSERT_LOCKED(); 1485 #endif 1486 /* do not stop exiting procs */ 1487 if (ISSET(p->p_flag, P_WEXIT)) 1488 return; 1489 1490 p->p_stat = SSTOP; 1491 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1492 atomic_setbits_int(&pr->ps_flags, PS_STOPPING); 1493 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1494 /* 1495 * We need this soft interrupt to be handled fast. 1496 * Extra calls to softclock don't hurt. 1497 */ 1498 softintr_schedule(proc_stop_si); 1499 if (sw) 1500 mi_switch(); 1501 } 1502 1503 /* 1504 * Called from a soft interrupt to send signals to the parents of stopped 1505 * processes. 1506 * We can't do this in proc_stop because it's called with nasty locks held 1507 * and we would need recursive scheduler lock to deal with that. 1508 */ 1509 void 1510 proc_stop_sweep(void *v) 1511 { 1512 struct process *pr; 1513 1514 LIST_FOREACH(pr, &allprocess, ps_list) { 1515 if ((pr->ps_flags & PS_STOPPING) == 0) 1516 continue; 1517 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1518 atomic_clearbits_int(&pr->ps_flags, PS_STOPPING); 1519 1520 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1521 prsignal(pr->ps_pptr, SIGCHLD); 1522 wakeup(pr->ps_pptr); 1523 } 1524 } 1525 1526 /* 1527 * Take the action for the specified signal 1528 * from the current set of pending signals. 1529 */ 1530 void 1531 postsig(struct proc *p, int signum, struct sigctx *sctx) 1532 { 1533 u_long trapno; 1534 int mask, returnmask; 1535 siginfo_t si; 1536 union sigval sigval; 1537 int code; 1538 1539 KASSERT(signum != 0); 1540 1541 mask = sigmask(signum); 1542 atomic_clearbits_int(&p->p_siglist, mask); 1543 sigval.sival_ptr = NULL; 1544 1545 if (p->p_sisig != signum) { 1546 trapno = 0; 1547 code = SI_USER; 1548 sigval.sival_ptr = NULL; 1549 } else { 1550 trapno = p->p_sitrapno; 1551 code = p->p_sicode; 1552 sigval = p->p_sigval; 1553 } 1554 initsiginfo(&si, signum, trapno, code, sigval); 1555 1556 #ifdef KTRACE 1557 if (KTRPOINT(p, KTR_PSIG)) { 1558 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1559 p->p_oldmask : p->p_sigmask, code, &si); 1560 } 1561 #endif 1562 if (sctx->sig_action == SIG_DFL) { 1563 /* 1564 * Default action, where the default is to kill 1565 * the process. (Other cases were ignored above.) 1566 */ 1567 KERNEL_LOCK(); 1568 sigexit(p, signum); 1569 /* NOTREACHED */ 1570 } else { 1571 /* 1572 * If we get here, the signal must be caught. 1573 */ 1574 #ifdef DIAGNOSTIC 1575 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1576 panic("postsig action"); 1577 #endif 1578 /* 1579 * Set the new mask value and also defer further 1580 * occurrences of this signal. 1581 * 1582 * Special case: user has done a sigpause. Here the 1583 * current mask is not of interest, but rather the 1584 * mask from before the sigpause is what we want 1585 * restored after the signal processing is completed. 1586 */ 1587 if (p->p_flag & P_SIGSUSPEND) { 1588 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1589 returnmask = p->p_oldmask; 1590 } else { 1591 returnmask = p->p_sigmask; 1592 } 1593 if (p->p_sisig == signum) { 1594 p->p_sisig = 0; 1595 p->p_sitrapno = 0; 1596 p->p_sicode = SI_USER; 1597 p->p_sigval.sival_ptr = NULL; 1598 } 1599 1600 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1601 sctx->sig_info, sctx->sig_onstack)) { 1602 KERNEL_LOCK(); 1603 sigexit(p, SIGILL); 1604 /* NOTREACHED */ 1605 } 1606 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1607 } 1608 } 1609 1610 /* 1611 * Force the current process to exit with the specified signal, dumping core 1612 * if appropriate. We bypass the normal tests for masked and caught signals, 1613 * allowing unrecoverable failures to terminate the process without changing 1614 * signal state. Mark the accounting record with the signal termination. 1615 * If dumping core, save the signal number for the debugger. Calls exit and 1616 * does not return. 1617 */ 1618 void 1619 sigexit(struct proc *p, int signum) 1620 { 1621 /* Mark process as going away */ 1622 atomic_setbits_int(&p->p_flag, P_WEXIT); 1623 1624 p->p_p->ps_acflag |= AXSIG; 1625 if (sigprop[signum] & SA_CORE) { 1626 p->p_sisig = signum; 1627 1628 /* if there are other threads, pause them */ 1629 if (P_HASSIBLING(p)) 1630 single_thread_set(p, SINGLE_UNWIND); 1631 1632 if (coredump(p) == 0) 1633 signum |= WCOREFLAG; 1634 } 1635 exit1(p, 0, signum, EXIT_NORMAL); 1636 /* NOTREACHED */ 1637 } 1638 1639 /* 1640 * Send uncatchable SIGABRT for coredump. 1641 */ 1642 void 1643 sigabort(struct proc *p) 1644 { 1645 struct sigaction sa; 1646 1647 KASSERT(p == curproc || panicstr || db_active); 1648 1649 memset(&sa, 0, sizeof sa); 1650 sa.sa_handler = SIG_DFL; 1651 setsigvec(p, SIGABRT, &sa); 1652 CLR(p->p_sigmask, sigmask(SIGABRT)); 1653 psignal(p, SIGABRT); 1654 } 1655 1656 /* 1657 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1658 * thread, and 0 otherwise. 1659 */ 1660 int 1661 sigismasked(struct proc *p, int sig) 1662 { 1663 struct process *pr = p->p_p; 1664 int rv; 1665 1666 KASSERT(p == curproc); 1667 1668 mtx_enter(&pr->ps_mtx); 1669 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1670 (p->p_sigmask & sigmask(sig)); 1671 mtx_leave(&pr->ps_mtx); 1672 1673 return !!rv; 1674 } 1675 1676 struct coredump_iostate { 1677 struct proc *io_proc; 1678 struct vnode *io_vp; 1679 struct ucred *io_cred; 1680 off_t io_offset; 1681 }; 1682 1683 /* 1684 * Dump core, into a file named "progname.core", unless the process was 1685 * setuid/setgid. 1686 */ 1687 int 1688 coredump(struct proc *p) 1689 { 1690 #ifdef SMALL_KERNEL 1691 return EPERM; 1692 #else 1693 struct process *pr = p->p_p; 1694 struct vnode *vp; 1695 struct ucred *cred = p->p_ucred; 1696 struct vmspace *vm = p->p_vmspace; 1697 struct nameidata nd; 1698 struct vattr vattr; 1699 struct coredump_iostate io; 1700 int error, len, incrash = 0; 1701 char *name; 1702 const char *dir = "/var/crash"; 1703 1704 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1705 1706 #ifdef PMAP_CHECK_COPYIN 1707 /* disable copyin checks, so we can write out text sections if needed */ 1708 p->p_vmspace->vm_map.check_copyin_count = 0; 1709 #endif 1710 1711 /* Don't dump if will exceed file size limit. */ 1712 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1713 return (EFBIG); 1714 1715 name = pool_get(&namei_pool, PR_WAITOK); 1716 1717 /* 1718 * If the process has inconsistent uids, nosuidcoredump 1719 * determines coredump placement policy. 1720 */ 1721 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1722 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1723 if (nosuidcoredump == 3) { 1724 /* 1725 * If the program directory does not exist, dumps of 1726 * that core will silently fail. 1727 */ 1728 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1729 dir, pr->ps_comm, pr->ps_pid); 1730 incrash = KERNELPATH; 1731 } else if (nosuidcoredump == 2) { 1732 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1733 dir, pr->ps_comm); 1734 incrash = KERNELPATH; 1735 } else { 1736 pool_put(&namei_pool, name); 1737 return (EPERM); 1738 } 1739 } else 1740 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1741 1742 if (len >= MAXPATHLEN) { 1743 pool_put(&namei_pool, name); 1744 return (EACCES); 1745 } 1746 1747 /* 1748 * Control the UID used to write out. The normal case uses 1749 * the real UID. If the sugid case is going to write into the 1750 * controlled directory, we do so as root. 1751 */ 1752 if (incrash == 0) { 1753 cred = crdup(cred); 1754 cred->cr_uid = cred->cr_ruid; 1755 cred->cr_gid = cred->cr_rgid; 1756 } else { 1757 if (p->p_fd->fd_rdir) { 1758 vrele(p->p_fd->fd_rdir); 1759 p->p_fd->fd_rdir = NULL; 1760 } 1761 p->p_ucred = crdup(p->p_ucred); 1762 crfree(cred); 1763 cred = p->p_ucred; 1764 crhold(cred); 1765 cred->cr_uid = 0; 1766 cred->cr_gid = 0; 1767 } 1768 1769 /* incrash should be 0 or KERNELPATH only */ 1770 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1771 1772 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1773 S_IRUSR | S_IWUSR); 1774 1775 if (error) 1776 goto out; 1777 1778 /* 1779 * Don't dump to non-regular files, files with links, or files 1780 * owned by someone else. 1781 */ 1782 vp = nd.ni_vp; 1783 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1784 VOP_UNLOCK(vp); 1785 vn_close(vp, FWRITE, cred, p); 1786 goto out; 1787 } 1788 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1789 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1790 vattr.va_uid != cred->cr_uid) { 1791 error = EACCES; 1792 VOP_UNLOCK(vp); 1793 vn_close(vp, FWRITE, cred, p); 1794 goto out; 1795 } 1796 VATTR_NULL(&vattr); 1797 vattr.va_size = 0; 1798 VOP_SETATTR(vp, &vattr, cred, p); 1799 pr->ps_acflag |= ACORE; 1800 1801 io.io_proc = p; 1802 io.io_vp = vp; 1803 io.io_cred = cred; 1804 io.io_offset = 0; 1805 VOP_UNLOCK(vp); 1806 vref(vp); 1807 error = vn_close(vp, FWRITE, cred, p); 1808 if (error == 0) 1809 error = coredump_elf(p, &io); 1810 vrele(vp); 1811 out: 1812 crfree(cred); 1813 pool_put(&namei_pool, name); 1814 return (error); 1815 #endif 1816 } 1817 1818 #ifndef SMALL_KERNEL 1819 int 1820 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1821 int isvnode) 1822 { 1823 struct coredump_iostate *io = cookie; 1824 off_t coffset = 0; 1825 size_t csize; 1826 int chunk, error; 1827 1828 csize = len; 1829 do { 1830 if (sigmask(SIGKILL) & 1831 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1832 return (EINTR); 1833 1834 /* Rest of the loop sleeps with lock held, so... */ 1835 yield(); 1836 1837 chunk = MIN(csize, MAXPHYS); 1838 error = vn_rdwr(UIO_WRITE, io->io_vp, 1839 (caddr_t)data + coffset, chunk, 1840 io->io_offset + coffset, segflg, 1841 IO_UNIT, io->io_cred, NULL, io->io_proc); 1842 if (error && (error != EFAULT || !isvnode)) { 1843 struct process *pr = io->io_proc->p_p; 1844 1845 if (error == ENOSPC) 1846 log(LOG_ERR, 1847 "coredump of %s(%d) failed, filesystem full\n", 1848 pr->ps_comm, pr->ps_pid); 1849 else 1850 log(LOG_ERR, 1851 "coredump of %s(%d), write failed: errno %d\n", 1852 pr->ps_comm, pr->ps_pid, error); 1853 return (error); 1854 } 1855 1856 coffset += chunk; 1857 csize -= chunk; 1858 } while (csize > 0); 1859 1860 io->io_offset += len; 1861 return (0); 1862 } 1863 1864 void 1865 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1866 { 1867 struct coredump_iostate *io = cookie; 1868 1869 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1870 } 1871 1872 #endif /* !SMALL_KERNEL */ 1873 1874 /* 1875 * Nonexistent system call-- signal process (may want to handle it). 1876 * Flag error in case process won't see signal immediately (blocked or ignored). 1877 */ 1878 int 1879 sys_nosys(struct proc *p, void *v, register_t *retval) 1880 { 1881 ptsignal(p, SIGSYS, STHREAD); 1882 return (ENOSYS); 1883 } 1884 1885 int 1886 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1887 { 1888 struct sys___thrsigdivert_args /* { 1889 syscallarg(sigset_t) sigmask; 1890 syscallarg(siginfo_t *) info; 1891 syscallarg(const struct timespec *) timeout; 1892 } */ *uap = v; 1893 struct sigctx ctx; 1894 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1895 siginfo_t si; 1896 uint64_t nsecs = INFSLP; 1897 int timeinvalid = 0; 1898 int error = 0; 1899 1900 memset(&si, 0, sizeof(si)); 1901 1902 if (SCARG(uap, timeout) != NULL) { 1903 struct timespec ts; 1904 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1905 return (error); 1906 #ifdef KTRACE 1907 if (KTRPOINT(p, KTR_STRUCT)) 1908 ktrreltimespec(p, &ts); 1909 #endif 1910 if (!timespecisvalid(&ts)) 1911 timeinvalid = 1; 1912 else 1913 nsecs = TIMESPEC_TO_NSEC(&ts); 1914 } 1915 1916 dosigsuspend(p, p->p_sigmask &~ mask); 1917 for (;;) { 1918 si.si_signo = cursig(p, &ctx); 1919 if (si.si_signo != 0) { 1920 sigset_t smask = sigmask(si.si_signo); 1921 if (smask & mask) { 1922 atomic_clearbits_int(&p->p_siglist, smask); 1923 error = 0; 1924 break; 1925 } 1926 } 1927 1928 /* per-POSIX, delay this error until after the above */ 1929 if (timeinvalid) 1930 error = EINVAL; 1931 /* per-POSIX, return immediately if timeout is zero-valued */ 1932 if (nsecs == 0) 1933 error = EAGAIN; 1934 1935 if (error != 0) 1936 break; 1937 1938 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1939 } 1940 1941 if (error == 0) { 1942 *retval = si.si_signo; 1943 if (SCARG(uap, info) != NULL) { 1944 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1945 #ifdef KTRACE 1946 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1947 ktrsiginfo(p, &si); 1948 #endif 1949 } 1950 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1951 /* 1952 * Restarting is wrong if there's a timeout, as it'll be 1953 * for the same interval again 1954 */ 1955 error = EINTR; 1956 } 1957 1958 return (error); 1959 } 1960 1961 void 1962 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1963 { 1964 memset(si, 0, sizeof(*si)); 1965 1966 si->si_signo = sig; 1967 si->si_code = code; 1968 if (code == SI_USER) { 1969 si->si_value = val; 1970 } else { 1971 switch (sig) { 1972 case SIGSEGV: 1973 case SIGILL: 1974 case SIGBUS: 1975 case SIGFPE: 1976 si->si_addr = val.sival_ptr; 1977 si->si_trapno = trapno; 1978 break; 1979 case SIGXFSZ: 1980 break; 1981 } 1982 } 1983 } 1984 1985 void 1986 userret(struct proc *p) 1987 { 1988 struct sigctx ctx; 1989 int signum; 1990 1991 if (p->p_flag & P_SUSPSINGLE) 1992 single_thread_check(p, 0); 1993 1994 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1995 if (p->p_flag & P_PROFPEND) { 1996 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1997 KERNEL_LOCK(); 1998 psignal(p, SIGPROF); 1999 KERNEL_UNLOCK(); 2000 } 2001 if (p->p_flag & P_ALRMPEND) { 2002 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 2003 KERNEL_LOCK(); 2004 psignal(p, SIGVTALRM); 2005 KERNEL_UNLOCK(); 2006 } 2007 2008 if (SIGPENDING(p) != 0) { 2009 while ((signum = cursig(p, &ctx)) != 0) 2010 postsig(p, signum, &ctx); 2011 } 2012 2013 /* 2014 * If P_SIGSUSPEND is still set here, then we still need to restore 2015 * the original sigmask before returning to userspace. Also, this 2016 * might unmask some pending signals, so we need to check a second 2017 * time for signals to post. 2018 */ 2019 if (p->p_flag & P_SIGSUSPEND) { 2020 p->p_sigmask = p->p_oldmask; 2021 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2022 2023 while ((signum = cursig(p, &ctx)) != 0) 2024 postsig(p, signum, &ctx); 2025 } 2026 2027 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2028 2029 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2030 } 2031 2032 int 2033 single_thread_check_locked(struct proc *p, int deep) 2034 { 2035 struct process *pr = p->p_p; 2036 2037 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 2038 2039 if (pr->ps_single == NULL || pr->ps_single == p) 2040 return (0); 2041 2042 do { 2043 /* if we're in deep, we need to unwind to the edge */ 2044 if (deep) { 2045 if (pr->ps_flags & PS_SINGLEUNWIND) 2046 return (ERESTART); 2047 if (pr->ps_flags & PS_SINGLEEXIT) 2048 return (EINTR); 2049 } 2050 2051 if (pr->ps_flags & PS_SINGLEEXIT) { 2052 mtx_leave(&pr->ps_mtx); 2053 KERNEL_LOCK(); 2054 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2055 /* NOTREACHED */ 2056 } 2057 2058 if (--pr->ps_singlecnt == 0) 2059 wakeup(&pr->ps_singlecnt); 2060 2061 /* not exiting and don't need to unwind, so suspend */ 2062 mtx_leave(&pr->ps_mtx); 2063 2064 SCHED_LOCK(); 2065 p->p_stat = SSTOP; 2066 mi_switch(); 2067 SCHED_UNLOCK(); 2068 mtx_enter(&pr->ps_mtx); 2069 } while (pr->ps_single != NULL); 2070 2071 return (0); 2072 } 2073 2074 int 2075 single_thread_check(struct proc *p, int deep) 2076 { 2077 int error; 2078 2079 mtx_enter(&p->p_p->ps_mtx); 2080 error = single_thread_check_locked(p, deep); 2081 mtx_leave(&p->p_p->ps_mtx); 2082 2083 return error; 2084 } 2085 2086 /* 2087 * Stop other threads in the process. The mode controls how and 2088 * where the other threads should stop: 2089 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2090 * single_thread_clear()) 2091 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2092 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2093 * - SINGLE_EXIT: unwind to kernel boundary and exit 2094 */ 2095 int 2096 single_thread_set(struct proc *p, int flags) 2097 { 2098 struct process *pr = p->p_p; 2099 struct proc *q; 2100 int error, mode = flags & SINGLE_MASK; 2101 2102 KASSERT(curproc == p); 2103 2104 mtx_enter(&pr->ps_mtx); 2105 error = single_thread_check_locked(p, flags & SINGLE_DEEP); 2106 if (error) { 2107 mtx_leave(&pr->ps_mtx); 2108 return error; 2109 } 2110 2111 switch (mode) { 2112 case SINGLE_SUSPEND: 2113 break; 2114 case SINGLE_UNWIND: 2115 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2116 break; 2117 case SINGLE_EXIT: 2118 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2119 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2120 break; 2121 #ifdef DIAGNOSTIC 2122 default: 2123 panic("single_thread_mode = %d", mode); 2124 #endif 2125 } 2126 KASSERT((p->p_flag & P_SUSPSINGLE) == 0); 2127 pr->ps_single = p; 2128 pr->ps_singlecnt = pr->ps_threadcnt; 2129 2130 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2131 if (q == p) 2132 continue; 2133 SCHED_LOCK(); 2134 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2135 switch (q->p_stat) { 2136 case SSTOP: 2137 if (mode == SINGLE_EXIT) { 2138 unsleep(q); 2139 setrunnable(q); 2140 } else 2141 --pr->ps_singlecnt; 2142 break; 2143 case SSLEEP: 2144 /* if it's not interruptible, then just have to wait */ 2145 if (q->p_flag & P_SINTR) { 2146 /* merely need to suspend? just stop it */ 2147 if (mode == SINGLE_SUSPEND) { 2148 q->p_stat = SSTOP; 2149 --pr->ps_singlecnt; 2150 break; 2151 } 2152 /* need to unwind or exit, so wake it */ 2153 unsleep(q); 2154 setrunnable(q); 2155 } 2156 break; 2157 case SONPROC: 2158 signotify(q); 2159 break; 2160 case SRUN: 2161 case SIDL: 2162 case SDEAD: 2163 break; 2164 } 2165 SCHED_UNLOCK(); 2166 } 2167 2168 /* count ourself out */ 2169 --pr->ps_singlecnt; 2170 mtx_leave(&pr->ps_mtx); 2171 2172 if ((flags & SINGLE_NOWAIT) == 0) 2173 single_thread_wait(pr, 1); 2174 2175 return 0; 2176 } 2177 2178 /* 2179 * Wait for other threads to stop. If recheck is false then the function 2180 * returns non-zero if the caller needs to restart the check else 0 is 2181 * returned. If recheck is true the return value is always 0. 2182 */ 2183 int 2184 single_thread_wait(struct process *pr, int recheck) 2185 { 2186 int wait; 2187 2188 /* wait until they're all suspended */ 2189 mtx_enter(&pr->ps_mtx); 2190 while ((wait = pr->ps_singlecnt > 0)) { 2191 msleep_nsec(&pr->ps_singlecnt, &pr->ps_mtx, PWAIT, "suspend", 2192 INFSLP); 2193 if (!recheck) 2194 break; 2195 } 2196 KASSERT((pr->ps_single->p_flag & P_SUSPSINGLE) == 0); 2197 mtx_leave(&pr->ps_mtx); 2198 2199 return wait; 2200 } 2201 2202 void 2203 single_thread_clear(struct proc *p, int flag) 2204 { 2205 struct process *pr = p->p_p; 2206 struct proc *q; 2207 2208 KASSERT(pr->ps_single == p); 2209 KASSERT(curproc == p); 2210 2211 mtx_enter(&pr->ps_mtx); 2212 pr->ps_single = NULL; 2213 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2214 2215 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2216 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2217 continue; 2218 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2219 2220 /* 2221 * if the thread was only stopped for single threading 2222 * then clearing that either makes it runnable or puts 2223 * it back into some sleep queue 2224 */ 2225 SCHED_LOCK(); 2226 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2227 if (q->p_wchan == NULL) 2228 setrunnable(q); 2229 else { 2230 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2231 q->p_stat = SSLEEP; 2232 } 2233 } 2234 SCHED_UNLOCK(); 2235 } 2236 mtx_leave(&pr->ps_mtx); 2237 } 2238 2239 void 2240 sigio_del(struct sigiolst *rmlist) 2241 { 2242 struct sigio *sigio; 2243 2244 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2245 LIST_REMOVE(sigio, sio_pgsigio); 2246 crfree(sigio->sio_ucred); 2247 free(sigio, M_SIGIO, sizeof(*sigio)); 2248 } 2249 } 2250 2251 void 2252 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2253 { 2254 struct sigio *sigio; 2255 2256 MUTEX_ASSERT_LOCKED(&sigio_lock); 2257 2258 sigio = sir->sir_sigio; 2259 if (sigio != NULL) { 2260 KASSERT(sigio->sio_myref == sir); 2261 sir->sir_sigio = NULL; 2262 2263 if (sigio->sio_pgid > 0) 2264 sigio->sio_proc = NULL; 2265 else 2266 sigio->sio_pgrp = NULL; 2267 LIST_REMOVE(sigio, sio_pgsigio); 2268 2269 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2270 } 2271 } 2272 2273 void 2274 sigio_free(struct sigio_ref *sir) 2275 { 2276 struct sigiolst rmlist; 2277 2278 if (sir->sir_sigio == NULL) 2279 return; 2280 2281 LIST_INIT(&rmlist); 2282 2283 mtx_enter(&sigio_lock); 2284 sigio_unlink(sir, &rmlist); 2285 mtx_leave(&sigio_lock); 2286 2287 sigio_del(&rmlist); 2288 } 2289 2290 void 2291 sigio_freelist(struct sigiolst *sigiolst) 2292 { 2293 struct sigiolst rmlist; 2294 struct sigio *sigio; 2295 2296 if (LIST_EMPTY(sigiolst)) 2297 return; 2298 2299 LIST_INIT(&rmlist); 2300 2301 mtx_enter(&sigio_lock); 2302 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2303 sigio_unlink(sigio->sio_myref, &rmlist); 2304 mtx_leave(&sigio_lock); 2305 2306 sigio_del(&rmlist); 2307 } 2308 2309 int 2310 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2311 { 2312 struct sigiolst rmlist; 2313 struct proc *p = curproc; 2314 struct pgrp *pgrp = NULL; 2315 struct process *pr = NULL; 2316 struct sigio *sigio; 2317 int error; 2318 pid_t pgid = *(int *)data; 2319 2320 if (pgid == 0) { 2321 sigio_free(sir); 2322 return (0); 2323 } 2324 2325 if (cmd == TIOCSPGRP) { 2326 if (pgid < 0) 2327 return (EINVAL); 2328 pgid = -pgid; 2329 } 2330 2331 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2332 sigio->sio_pgid = pgid; 2333 sigio->sio_ucred = crhold(p->p_ucred); 2334 sigio->sio_myref = sir; 2335 2336 LIST_INIT(&rmlist); 2337 2338 /* 2339 * The kernel lock, and not sleeping between prfind()/pgfind() and 2340 * linking of the sigio ensure that the process or process group does 2341 * not disappear unexpectedly. 2342 */ 2343 KERNEL_LOCK(); 2344 mtx_enter(&sigio_lock); 2345 2346 if (pgid > 0) { 2347 pr = prfind(pgid); 2348 if (pr == NULL) { 2349 error = ESRCH; 2350 goto fail; 2351 } 2352 2353 /* 2354 * Policy - Don't allow a process to FSETOWN a process 2355 * in another session. 2356 * 2357 * Remove this test to allow maximum flexibility or 2358 * restrict FSETOWN to the current process or process 2359 * group for maximum safety. 2360 */ 2361 if (pr->ps_session != p->p_p->ps_session) { 2362 error = EPERM; 2363 goto fail; 2364 } 2365 2366 if ((pr->ps_flags & PS_EXITING) != 0) { 2367 error = ESRCH; 2368 goto fail; 2369 } 2370 } else /* if (pgid < 0) */ { 2371 pgrp = pgfind(-pgid); 2372 if (pgrp == NULL) { 2373 error = ESRCH; 2374 goto fail; 2375 } 2376 2377 /* 2378 * Policy - Don't allow a process to FSETOWN a process 2379 * in another session. 2380 * 2381 * Remove this test to allow maximum flexibility or 2382 * restrict FSETOWN to the current process or process 2383 * group for maximum safety. 2384 */ 2385 if (pgrp->pg_session != p->p_p->ps_session) { 2386 error = EPERM; 2387 goto fail; 2388 } 2389 } 2390 2391 if (pgid > 0) { 2392 sigio->sio_proc = pr; 2393 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2394 } else { 2395 sigio->sio_pgrp = pgrp; 2396 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2397 } 2398 2399 sigio_unlink(sir, &rmlist); 2400 sir->sir_sigio = sigio; 2401 2402 mtx_leave(&sigio_lock); 2403 KERNEL_UNLOCK(); 2404 2405 sigio_del(&rmlist); 2406 2407 return (0); 2408 2409 fail: 2410 mtx_leave(&sigio_lock); 2411 KERNEL_UNLOCK(); 2412 2413 crfree(sigio->sio_ucred); 2414 free(sigio, M_SIGIO, sizeof(*sigio)); 2415 2416 return (error); 2417 } 2418 2419 void 2420 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2421 { 2422 struct sigio *sigio; 2423 pid_t pgid = 0; 2424 2425 mtx_enter(&sigio_lock); 2426 sigio = sir->sir_sigio; 2427 if (sigio != NULL) 2428 pgid = sigio->sio_pgid; 2429 mtx_leave(&sigio_lock); 2430 2431 if (cmd == TIOCGPGRP) 2432 pgid = -pgid; 2433 2434 *(int *)data = pgid; 2435 } 2436 2437 void 2438 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2439 { 2440 struct sigiolst rmlist; 2441 struct sigio *newsigio, *sigio; 2442 2443 sigio_free(dst); 2444 2445 if (src->sir_sigio == NULL) 2446 return; 2447 2448 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2449 LIST_INIT(&rmlist); 2450 2451 mtx_enter(&sigio_lock); 2452 2453 sigio = src->sir_sigio; 2454 if (sigio == NULL) { 2455 mtx_leave(&sigio_lock); 2456 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2457 return; 2458 } 2459 2460 newsigio->sio_pgid = sigio->sio_pgid; 2461 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2462 newsigio->sio_myref = dst; 2463 if (newsigio->sio_pgid > 0) { 2464 newsigio->sio_proc = sigio->sio_proc; 2465 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2466 sio_pgsigio); 2467 } else { 2468 newsigio->sio_pgrp = sigio->sio_pgrp; 2469 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2470 sio_pgsigio); 2471 } 2472 2473 sigio_unlink(dst, &rmlist); 2474 dst->sir_sigio = newsigio; 2475 2476 mtx_leave(&sigio_lock); 2477 2478 sigio_del(&rmlist); 2479 } 2480