1 /* $OpenBSD: kern_sig.c,v 1.353 2024/12/17 14:45:00 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 int proc_trap(struct proc *, int); 119 void proc_stop(struct proc *p, int); 120 void proc_stop_sweep(void *); 121 void *proc_stop_si; 122 123 void setsigctx(struct proc *, int, struct sigctx *); 124 void postsig_done(struct proc *, int, sigset_t, int); 125 void postsig(struct proc *, int, struct sigctx *); 126 int cansignal(struct proc *, struct process *, int); 127 128 void ptsignal_locked(struct proc *, int, enum signal_type); 129 130 struct pool sigacts_pool; /* memory pool for sigacts structures */ 131 132 void sigio_del(struct sigiolst *); 133 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 134 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 135 136 /* 137 * Can thread p, send the signal signum to process qr? 138 */ 139 int 140 cansignal(struct proc *p, struct process *qr, int signum) 141 { 142 struct process *pr = p->p_p; 143 struct ucred *uc = p->p_ucred; 144 struct ucred *quc = qr->ps_ucred; 145 146 if (uc->cr_uid == 0) 147 return (1); /* root can always signal */ 148 149 if (pr == qr) 150 return (1); /* process can always signal itself */ 151 152 /* optimization: if the same creds then the tests below will pass */ 153 if (uc == quc) 154 return (1); 155 156 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 157 return (1); /* SIGCONT in session */ 158 159 /* 160 * Using kill(), only certain signals can be sent to setugid 161 * child processes 162 */ 163 if (qr->ps_flags & PS_SUGID) { 164 switch (signum) { 165 case 0: 166 case SIGKILL: 167 case SIGINT: 168 case SIGTERM: 169 case SIGALRM: 170 case SIGSTOP: 171 case SIGTTIN: 172 case SIGTTOU: 173 case SIGTSTP: 174 case SIGHUP: 175 case SIGUSR1: 176 case SIGUSR2: 177 if (uc->cr_ruid == quc->cr_ruid || 178 uc->cr_uid == quc->cr_ruid) 179 return (1); 180 } 181 return (0); 182 } 183 184 if (uc->cr_ruid == quc->cr_ruid || 185 uc->cr_ruid == quc->cr_svuid || 186 uc->cr_uid == quc->cr_ruid || 187 uc->cr_uid == quc->cr_svuid) 188 return (1); 189 return (0); 190 } 191 192 /* 193 * Initialize signal-related data structures. 194 */ 195 void 196 signal_init(void) 197 { 198 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 199 NULL); 200 if (proc_stop_si == NULL) 201 panic("signal_init failed to register softintr"); 202 203 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 204 PR_WAITOK, "sigapl", NULL); 205 } 206 207 /* 208 * Initialize a new sigaltstack structure. 209 */ 210 void 211 sigstkinit(struct sigaltstack *ss) 212 { 213 ss->ss_flags = SS_DISABLE; 214 ss->ss_size = 0; 215 ss->ss_sp = NULL; 216 } 217 218 /* 219 * Create an initial sigacts structure, using the same signal state 220 * as pr. 221 */ 222 struct sigacts * 223 sigactsinit(struct process *pr) 224 { 225 struct sigacts *ps; 226 227 ps = pool_get(&sigacts_pool, PR_WAITOK); 228 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 229 return (ps); 230 } 231 232 /* 233 * Release a sigacts structure. 234 */ 235 void 236 sigactsfree(struct sigacts *ps) 237 { 238 pool_put(&sigacts_pool, ps); 239 } 240 241 int 242 sys_sigaction(struct proc *p, void *v, register_t *retval) 243 { 244 struct sys_sigaction_args /* { 245 syscallarg(int) signum; 246 syscallarg(const struct sigaction *) nsa; 247 syscallarg(struct sigaction *) osa; 248 } */ *uap = v; 249 struct sigaction vec; 250 #ifdef KTRACE 251 struct sigaction ovec; 252 #endif 253 struct sigaction *sa; 254 const struct sigaction *nsa; 255 struct sigaction *osa; 256 struct sigacts *ps = p->p_p->ps_sigacts; 257 int signum; 258 int bit, error; 259 260 signum = SCARG(uap, signum); 261 nsa = SCARG(uap, nsa); 262 osa = SCARG(uap, osa); 263 264 if (signum <= 0 || signum >= NSIG || 265 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 266 return (EINVAL); 267 sa = &vec; 268 if (osa) { 269 mtx_enter(&p->p_p->ps_mtx); 270 sa->sa_handler = ps->ps_sigact[signum]; 271 sa->sa_mask = ps->ps_catchmask[signum]; 272 bit = sigmask(signum); 273 sa->sa_flags = 0; 274 if ((ps->ps_sigonstack & bit) != 0) 275 sa->sa_flags |= SA_ONSTACK; 276 if ((ps->ps_sigintr & bit) == 0) 277 sa->sa_flags |= SA_RESTART; 278 if ((ps->ps_sigreset & bit) != 0) 279 sa->sa_flags |= SA_RESETHAND; 280 if ((ps->ps_siginfo & bit) != 0) 281 sa->sa_flags |= SA_SIGINFO; 282 if (signum == SIGCHLD) { 283 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 284 sa->sa_flags |= SA_NOCLDSTOP; 285 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 286 sa->sa_flags |= SA_NOCLDWAIT; 287 } 288 mtx_leave(&p->p_p->ps_mtx); 289 if ((sa->sa_mask & bit) == 0) 290 sa->sa_flags |= SA_NODEFER; 291 sa->sa_mask &= ~bit; 292 error = copyout(sa, osa, sizeof (vec)); 293 if (error) 294 return (error); 295 #ifdef KTRACE 296 if (KTRPOINT(p, KTR_STRUCT)) 297 ovec = vec; 298 #endif 299 } 300 if (nsa) { 301 error = copyin(nsa, sa, sizeof (vec)); 302 if (error) 303 return (error); 304 #ifdef KTRACE 305 if (KTRPOINT(p, KTR_STRUCT)) 306 ktrsigaction(p, sa); 307 #endif 308 setsigvec(p, signum, sa); 309 } 310 #ifdef KTRACE 311 if (osa && KTRPOINT(p, KTR_STRUCT)) 312 ktrsigaction(p, &ovec); 313 #endif 314 return (0); 315 } 316 317 void 318 setsigvec(struct proc *p, int signum, struct sigaction *sa) 319 { 320 struct sigacts *ps = p->p_p->ps_sigacts; 321 int bit; 322 323 bit = sigmask(signum); 324 325 mtx_enter(&p->p_p->ps_mtx); 326 ps->ps_sigact[signum] = sa->sa_handler; 327 if ((sa->sa_flags & SA_NODEFER) == 0) 328 sa->sa_mask |= sigmask(signum); 329 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 330 if (signum == SIGCHLD) { 331 if (sa->sa_flags & SA_NOCLDSTOP) 332 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 333 else 334 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 335 /* 336 * If the SA_NOCLDWAIT flag is set or the handler 337 * is SIG_IGN we reparent the dying child to PID 1 338 * (init) which will reap the zombie. Because we use 339 * init to do our dirty work we never set SAS_NOCLDWAIT 340 * for PID 1. 341 * XXX exit1 rework means this is unnecessary? 342 */ 343 if (initprocess->ps_sigacts != ps && 344 ((sa->sa_flags & SA_NOCLDWAIT) || 345 sa->sa_handler == SIG_IGN)) 346 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 347 else 348 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 349 } 350 if ((sa->sa_flags & SA_RESETHAND) != 0) 351 ps->ps_sigreset |= bit; 352 else 353 ps->ps_sigreset &= ~bit; 354 if ((sa->sa_flags & SA_SIGINFO) != 0) 355 ps->ps_siginfo |= bit; 356 else 357 ps->ps_siginfo &= ~bit; 358 if ((sa->sa_flags & SA_RESTART) == 0) 359 ps->ps_sigintr |= bit; 360 else 361 ps->ps_sigintr &= ~bit; 362 if ((sa->sa_flags & SA_ONSTACK) != 0) 363 ps->ps_sigonstack |= bit; 364 else 365 ps->ps_sigonstack &= ~bit; 366 /* 367 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 368 * and for signals set to SIG_DFL where the default is to ignore. 369 * However, don't put SIGCONT in ps_sigignore, 370 * as we have to restart the process. 371 */ 372 if (sa->sa_handler == SIG_IGN || 373 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 374 atomic_clearbits_int(&p->p_siglist, bit); 375 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 376 if (signum != SIGCONT) 377 ps->ps_sigignore |= bit; /* easier in psignal */ 378 ps->ps_sigcatch &= ~bit; 379 } else { 380 ps->ps_sigignore &= ~bit; 381 if (sa->sa_handler == SIG_DFL) 382 ps->ps_sigcatch &= ~bit; 383 else 384 ps->ps_sigcatch |= bit; 385 } 386 mtx_leave(&p->p_p->ps_mtx); 387 } 388 389 /* 390 * Initialize signal state for process 0; 391 * set to ignore signals that are ignored by default. 392 */ 393 void 394 siginit(struct sigacts *ps) 395 { 396 int i; 397 398 for (i = 0; i < NSIG; i++) 399 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 400 ps->ps_sigignore |= sigmask(i); 401 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 402 } 403 404 /* 405 * Reset signals for an exec by the specified thread. 406 */ 407 void 408 execsigs(struct proc *p) 409 { 410 struct sigacts *ps; 411 int nc, mask; 412 413 ps = p->p_p->ps_sigacts; 414 mtx_enter(&p->p_p->ps_mtx); 415 416 /* 417 * Reset caught signals. Held signals remain held 418 * through p_sigmask (unless they were caught, 419 * and are now ignored by default). 420 */ 421 while (ps->ps_sigcatch) { 422 nc = ffs((long)ps->ps_sigcatch); 423 mask = sigmask(nc); 424 ps->ps_sigcatch &= ~mask; 425 if (sigprop[nc] & SA_IGNORE) { 426 if (nc != SIGCONT) 427 ps->ps_sigignore |= mask; 428 atomic_clearbits_int(&p->p_siglist, mask); 429 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 430 } 431 ps->ps_sigact[nc] = SIG_DFL; 432 } 433 /* 434 * Reset stack state to the user stack. 435 * Clear set of signals caught on the signal stack. 436 */ 437 sigstkinit(&p->p_sigstk); 438 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 439 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 440 ps->ps_sigact[SIGCHLD] = SIG_DFL; 441 mtx_leave(&p->p_p->ps_mtx); 442 } 443 444 /* 445 * Manipulate signal mask. 446 * Note that we receive new mask, not pointer, 447 * and return old mask as return value; 448 * the library stub does the rest. 449 */ 450 int 451 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 452 { 453 struct sys_sigprocmask_args /* { 454 syscallarg(int) how; 455 syscallarg(sigset_t) mask; 456 } */ *uap = v; 457 int error = 0; 458 sigset_t mask; 459 460 KASSERT(p == curproc); 461 462 *retval = p->p_sigmask; 463 mask = SCARG(uap, mask) &~ sigcantmask; 464 465 switch (SCARG(uap, how)) { 466 case SIG_BLOCK: 467 SET(p->p_sigmask, mask); 468 break; 469 case SIG_UNBLOCK: 470 CLR(p->p_sigmask, mask); 471 break; 472 case SIG_SETMASK: 473 p->p_sigmask = mask; 474 break; 475 default: 476 error = EINVAL; 477 break; 478 } 479 return (error); 480 } 481 482 int 483 sys_sigpending(struct proc *p, void *v, register_t *retval) 484 { 485 *retval = p->p_siglist | p->p_p->ps_siglist; 486 return (0); 487 } 488 489 /* 490 * Temporarily replace calling proc's signal mask for the duration of a 491 * system call. Original signal mask will be restored by userret(). 492 */ 493 void 494 dosigsuspend(struct proc *p, sigset_t newmask) 495 { 496 KASSERT(p == curproc); 497 498 p->p_oldmask = p->p_sigmask; 499 p->p_sigmask = newmask; 500 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 501 } 502 503 /* 504 * Suspend thread until signal, providing mask to be set 505 * in the meantime. Note nonstandard calling convention: 506 * libc stub passes mask, not pointer, to save a copyin. 507 */ 508 int 509 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 510 { 511 struct sys_sigsuspend_args /* { 512 syscallarg(int) mask; 513 } */ *uap = v; 514 515 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 516 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 517 continue; 518 /* always return EINTR rather than ERESTART... */ 519 return (EINTR); 520 } 521 522 int 523 sigonstack(size_t stack) 524 { 525 const struct sigaltstack *ss = &curproc->p_sigstk; 526 527 return (ss->ss_flags & SS_DISABLE ? 0 : 528 (stack - (size_t)ss->ss_sp < ss->ss_size)); 529 } 530 531 int 532 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 533 { 534 struct sys_sigaltstack_args /* { 535 syscallarg(const struct sigaltstack *) nss; 536 syscallarg(struct sigaltstack *) oss; 537 } */ *uap = v; 538 struct sigaltstack ss; 539 const struct sigaltstack *nss; 540 struct sigaltstack *oss; 541 int onstack = sigonstack(PROC_STACK(p)); 542 int error; 543 544 nss = SCARG(uap, nss); 545 oss = SCARG(uap, oss); 546 547 if (oss != NULL) { 548 ss = p->p_sigstk; 549 if (onstack) 550 ss.ss_flags |= SS_ONSTACK; 551 if ((error = copyout(&ss, oss, sizeof(ss)))) 552 return (error); 553 } 554 if (nss == NULL) 555 return (0); 556 error = copyin(nss, &ss, sizeof(ss)); 557 if (error) 558 return (error); 559 if (onstack) 560 return (EPERM); 561 if (ss.ss_flags & ~SS_DISABLE) 562 return (EINVAL); 563 if (ss.ss_flags & SS_DISABLE) { 564 p->p_sigstk.ss_flags = ss.ss_flags; 565 return (0); 566 } 567 if (ss.ss_size < MINSIGSTKSZ) 568 return (ENOMEM); 569 570 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 571 if (error) 572 return (error); 573 574 p->p_sigstk = ss; 575 return (0); 576 } 577 578 int 579 sys_kill(struct proc *cp, void *v, register_t *retval) 580 { 581 struct sys_kill_args /* { 582 syscallarg(int) pid; 583 syscallarg(int) signum; 584 } */ *uap = v; 585 struct process *pr; 586 int pid = SCARG(uap, pid); 587 int signum = SCARG(uap, signum); 588 int error; 589 int zombie = 0; 590 591 if ((error = pledge_kill(cp, pid)) != 0) 592 return (error); 593 if (((u_int)signum) >= NSIG) 594 return (EINVAL); 595 if (pid > 0) { 596 if ((pr = prfind(pid)) == NULL) { 597 if ((pr = zombiefind(pid)) == NULL) 598 return (ESRCH); 599 else 600 zombie = 1; 601 } 602 if (!cansignal(cp, pr, signum)) 603 return (EPERM); 604 605 /* kill single process */ 606 if (signum && !zombie) 607 prsignal(pr, signum); 608 return (0); 609 } 610 switch (pid) { 611 case -1: /* broadcast signal */ 612 return (killpg1(cp, signum, 0, 1)); 613 case 0: /* signal own process group */ 614 return (killpg1(cp, signum, 0, 0)); 615 default: /* negative explicit process group */ 616 return (killpg1(cp, signum, -pid, 0)); 617 } 618 } 619 620 int 621 sys_thrkill(struct proc *cp, void *v, register_t *retval) 622 { 623 struct sys_thrkill_args /* { 624 syscallarg(pid_t) tid; 625 syscallarg(int) signum; 626 syscallarg(void *) tcb; 627 } */ *uap = v; 628 struct proc *p; 629 int tid = SCARG(uap, tid); 630 int signum = SCARG(uap, signum); 631 void *tcb; 632 633 if (((u_int)signum) >= NSIG) 634 return (EINVAL); 635 636 p = tid ? tfind_user(tid, cp->p_p) : cp; 637 if (p == NULL) 638 return (ESRCH); 639 640 /* optionally require the target thread to have the given tcb addr */ 641 tcb = SCARG(uap, tcb); 642 if (tcb != NULL && tcb != TCB_GET(p)) 643 return (ESRCH); 644 645 if (signum) 646 ptsignal(p, signum, STHREAD); 647 return (0); 648 } 649 650 /* 651 * Common code for kill process group/broadcast kill. 652 * cp is calling process. 653 */ 654 int 655 killpg1(struct proc *cp, int signum, int pgid, int all) 656 { 657 struct process *pr; 658 struct pgrp *pgrp; 659 int nfound = 0; 660 661 if (all) { 662 /* 663 * broadcast 664 */ 665 LIST_FOREACH(pr, &allprocess, ps_list) { 666 if (pr->ps_pid <= 1 || 667 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 668 pr == cp->p_p || !cansignal(cp, pr, signum)) 669 continue; 670 nfound++; 671 if (signum) 672 prsignal(pr, signum); 673 } 674 } else { 675 if (pgid == 0) 676 /* 677 * zero pgid means send to my process group. 678 */ 679 pgrp = cp->p_p->ps_pgrp; 680 else { 681 pgrp = pgfind(pgid); 682 if (pgrp == NULL) 683 return (ESRCH); 684 } 685 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 686 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 687 !cansignal(cp, pr, signum)) 688 continue; 689 nfound++; 690 if (signum) 691 prsignal(pr, signum); 692 } 693 } 694 return (nfound ? 0 : ESRCH); 695 } 696 697 #define CANDELIVER(uid, euid, pr) \ 698 (euid == 0 || \ 699 (uid) == (pr)->ps_ucred->cr_ruid || \ 700 (uid) == (pr)->ps_ucred->cr_svuid || \ 701 (uid) == (pr)->ps_ucred->cr_uid || \ 702 (euid) == (pr)->ps_ucred->cr_ruid || \ 703 (euid) == (pr)->ps_ucred->cr_svuid || \ 704 (euid) == (pr)->ps_ucred->cr_uid) 705 706 #define CANSIGIO(cr, pr) \ 707 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 708 709 /* 710 * Send a signal to a process group. If checktty is 1, 711 * limit to members which have a controlling terminal. 712 */ 713 void 714 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 715 { 716 struct process *pr; 717 718 if (pgrp) 719 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 720 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 721 prsignal(pr, signum); 722 } 723 724 /* 725 * Send a SIGIO or SIGURG signal to a process or process group using stored 726 * credentials rather than those of the current process. 727 */ 728 void 729 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 730 { 731 struct process *pr; 732 struct sigio *sigio; 733 734 if (sir->sir_sigio == NULL) 735 return; 736 737 KERNEL_LOCK(); 738 mtx_enter(&sigio_lock); 739 sigio = sir->sir_sigio; 740 if (sigio == NULL) 741 goto out; 742 if (sigio->sio_pgid > 0) { 743 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 744 prsignal(sigio->sio_proc, sig); 745 } else if (sigio->sio_pgid < 0) { 746 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 747 if (CANSIGIO(sigio->sio_ucred, pr) && 748 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 749 prsignal(pr, sig); 750 } 751 } 752 out: 753 mtx_leave(&sigio_lock); 754 KERNEL_UNLOCK(); 755 } 756 757 /* 758 * Recalculate the signal mask and reset the signal disposition after 759 * usermode frame for delivery is formed. 760 */ 761 void 762 postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 763 { 764 p->p_ru.ru_nsignals++; 765 SET(p->p_sigmask, catchmask); 766 if (reset != 0) { 767 sigset_t mask = sigmask(signum); 768 struct sigacts *ps = p->p_p->ps_sigacts; 769 770 mtx_enter(&p->p_p->ps_mtx); 771 ps->ps_sigcatch &= ~mask; 772 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 773 ps->ps_sigignore |= mask; 774 ps->ps_sigact[signum] = SIG_DFL; 775 mtx_leave(&p->p_p->ps_mtx); 776 } 777 } 778 779 /* 780 * Send a signal caused by a trap to the current thread 781 * If it will be caught immediately, deliver it with correct code. 782 * Otherwise, post it normally. 783 */ 784 void 785 trapsignal(struct proc *p, int signum, u_long trapno, int code, 786 union sigval sigval) 787 { 788 struct process *pr = p->p_p; 789 struct sigctx ctx; 790 int mask; 791 792 switch (signum) { 793 case SIGILL: 794 if (code == ILL_BTCFI) { 795 pr->ps_acflag |= ABTCFI; 796 break; 797 } 798 /* FALLTHROUGH */ 799 case SIGBUS: 800 case SIGSEGV: 801 pr->ps_acflag |= ATRAP; 802 break; 803 } 804 805 mask = sigmask(signum); 806 setsigctx(p, signum, &ctx); 807 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 808 (p->p_sigmask & mask) == 0) { 809 siginfo_t si; 810 811 initsiginfo(&si, signum, trapno, code, sigval); 812 #ifdef KTRACE 813 if (KTRPOINT(p, KTR_PSIG)) { 814 ktrpsig(p, signum, ctx.sig_action, 815 p->p_sigmask, code, &si); 816 } 817 #endif 818 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 819 ctx.sig_info, ctx.sig_onstack)) { 820 KERNEL_LOCK(); 821 sigexit(p, SIGILL); 822 /* NOTREACHED */ 823 } 824 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 825 } else { 826 p->p_sisig = signum; 827 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 828 p->p_sicode = code; 829 p->p_sigval = sigval; 830 831 /* 832 * If traced, stop if signal is masked, and stay stopped 833 * until released by the debugger. If our parent process 834 * is waiting for us, don't hang as we could deadlock. 835 */ 836 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 837 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 838 signum = proc_trap(p, signum); 839 840 mask = sigmask(signum); 841 setsigctx(p, signum, &ctx); 842 843 /* 844 * If we are no longer being traced, or the parent 845 * didn't give us a signal, skip sending the signal. 846 */ 847 if ((pr->ps_flags & PS_TRACED) == 0 || signum == 0) 848 return; 849 850 /* update signal info */ 851 p->p_sisig = signum; 852 } 853 854 /* 855 * Signals like SIGBUS and SIGSEGV should not, when 856 * generated by the kernel, be ignorable or blockable. 857 * If it is and we're not being traced, then just kill 858 * the process. 859 * After vfs_shutdown(9), init(8) cannot receive signals 860 * because new code pages of the signal handler cannot be 861 * mapped from halted storage. init(8) may not die or the 862 * kernel panics. Better loop between signal handler and 863 * page fault trap until the machine is halted. 864 */ 865 if ((pr->ps_flags & PS_TRACED) == 0 && 866 (sigprop[signum] & SA_KILL) && 867 ((p->p_sigmask & mask) || ctx.sig_ignore) && 868 pr->ps_pid != 1) { 869 KERNEL_LOCK(); 870 sigexit(p, signum); 871 /* NOTREACHED */ 872 } 873 ptsignal(p, signum, STHREAD); 874 } 875 } 876 877 /* 878 * Send the signal to the process. If the signal has an action, the action 879 * is usually performed by the target process rather than the caller; we add 880 * the signal to the set of pending signals for the process. 881 * 882 * Exceptions: 883 * o When a stop signal is sent to a sleeping process that takes the 884 * default action, the process is stopped without awakening it. 885 * o SIGCONT restarts stopped processes (or puts them back to sleep) 886 * regardless of the signal action (eg, blocked or ignored). 887 * 888 * Other ignored signals are discarded immediately. 889 */ 890 void 891 psignal(struct proc *p, int signum) 892 { 893 ptsignal(p, signum, SPROCESS); 894 } 895 896 void 897 prsignal(struct process *pr, int signum) 898 { 899 mtx_enter(&pr->ps_mtx); 900 /* Ignore signal if the target process is exiting */ 901 if (pr->ps_flags & PS_EXITING) { 902 mtx_leave(&pr->ps_mtx); 903 return; 904 } 905 ptsignal_locked(TAILQ_FIRST(&pr->ps_threads), signum, SPROCESS); 906 mtx_leave(&pr->ps_mtx); 907 } 908 909 /* 910 * type = SPROCESS process signal, can be diverted (sigwait()) 911 * type = STHREAD thread signal, but should be propagated if unhandled 912 * type = SPROPAGATED propagated to this thread, so don't propagate again 913 */ 914 void 915 ptsignal(struct proc *p, int signum, enum signal_type type) 916 { 917 struct process *pr = p->p_p; 918 919 mtx_enter(&pr->ps_mtx); 920 ptsignal_locked(p, signum, type); 921 mtx_leave(&pr->ps_mtx); 922 } 923 924 void 925 ptsignal_locked(struct proc *p, int signum, enum signal_type type) 926 { 927 int prop; 928 sig_t action, altaction = SIG_DFL; 929 sigset_t mask, sigmask; 930 int *siglist; 931 struct process *pr = p->p_p; 932 struct proc *q; 933 int wakeparent = 0; 934 935 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 936 937 #ifdef DIAGNOSTIC 938 if ((u_int)signum >= NSIG || signum == 0) 939 panic("psignal signal number"); 940 #endif 941 942 /* Ignore signal if the target process is exiting */ 943 if (pr->ps_flags & PS_EXITING) 944 return; 945 946 mask = sigmask(signum); 947 sigmask = READ_ONCE(p->p_sigmask); 948 949 if (type == SPROCESS) { 950 sigset_t tmpmask; 951 952 /* Accept SIGKILL to coredumping processes */ 953 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 954 atomic_setbits_int(&pr->ps_siglist, mask); 955 return; 956 } 957 958 /* 959 * If the current thread can process the signal 960 * immediately (it's unblocked) then have it take it. 961 */ 962 q = curproc; 963 tmpmask = READ_ONCE(q->p_sigmask); 964 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 965 (tmpmask & mask) == 0) { 966 p = q; 967 sigmask = tmpmask; 968 } else { 969 /* 970 * A process-wide signal can be diverted to a 971 * different thread that's in sigwait() for this 972 * signal. If there isn't such a thread, then 973 * pick a thread that doesn't have it blocked so 974 * that the stop/kill consideration isn't 975 * delayed. Otherwise, mark it pending on the 976 * main thread. 977 */ 978 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 979 980 /* ignore exiting threads */ 981 if (q->p_flag & P_WEXIT) 982 continue; 983 984 /* skip threads that have the signal blocked */ 985 tmpmask = READ_ONCE(q->p_sigmask); 986 if ((tmpmask & mask) != 0) 987 continue; 988 989 /* okay, could send to this thread */ 990 p = q; 991 sigmask = tmpmask; 992 993 /* 994 * sigsuspend, sigwait, ppoll/pselect, etc? 995 * Definitely go to this thread, as it's 996 * already blocked in the kernel. 997 */ 998 if (q->p_flag & P_SIGSUSPEND) 999 break; 1000 } 1001 } 1002 } 1003 1004 if (type != SPROPAGATED) 1005 knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); 1006 1007 prop = sigprop[signum]; 1008 1009 /* 1010 * If proc is traced, always give parent a chance. 1011 */ 1012 if (pr->ps_flags & PS_TRACED) { 1013 action = SIG_DFL; 1014 } else { 1015 sigset_t sigcatch, sigignore; 1016 1017 /* 1018 * If the signal is being ignored, 1019 * then we forget about it immediately. 1020 * (Note: we don't set SIGCONT in ps_sigignore, 1021 * and if it is set to SIG_IGN, 1022 * action will be SIG_DFL here.) 1023 */ 1024 sigignore = pr->ps_sigacts->ps_sigignore; 1025 sigcatch = pr->ps_sigacts->ps_sigcatch; 1026 1027 if (sigignore & mask) 1028 return; 1029 if (sigmask & mask) { 1030 action = SIG_HOLD; 1031 if (sigcatch & mask) 1032 altaction = SIG_CATCH; 1033 } else if (sigcatch & mask) { 1034 action = SIG_CATCH; 1035 } else { 1036 action = SIG_DFL; 1037 1038 if (prop & SA_KILL && pr->ps_nice > NZERO) 1039 pr->ps_nice = NZERO; 1040 1041 /* 1042 * If sending a tty stop signal to a member of an 1043 * orphaned process group, discard the signal here if 1044 * the action is default; don't stop the process below 1045 * if sleeping, and don't clear any pending SIGCONT. 1046 */ 1047 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1048 return; 1049 } 1050 } 1051 /* 1052 * If delivered to process, mark as pending there. Continue and stop 1053 * signals will be propagated to all threads. So they are always 1054 * marked at thread level. 1055 */ 1056 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1057 if (prop & (SA_CONT | SA_STOP)) 1058 siglist = &p->p_siglist; 1059 1060 /* 1061 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1062 */ 1063 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1064 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1065 if (q != p) 1066 ptsignal_locked(q, signum, SPROPAGATED); 1067 1068 SCHED_LOCK(); 1069 1070 switch (p->p_stat) { 1071 1072 case SSTOP: 1073 /* 1074 * If traced process is already stopped, 1075 * then no further action is necessary. 1076 */ 1077 if (pr->ps_flags & PS_TRACED) 1078 goto out; 1079 1080 /* 1081 * Kill signal always sets processes running. 1082 */ 1083 if (signum == SIGKILL) { 1084 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1085 /* Raise priority to at least PUSER. */ 1086 if (p->p_usrpri > PUSER) 1087 p->p_usrpri = PUSER; 1088 unsleep(p); 1089 setrunnable(p); 1090 goto out; 1091 } 1092 1093 if (prop & SA_CONT) { 1094 /* 1095 * If SIGCONT is default (or ignored), we continue the 1096 * process but don't leave the signal in p_siglist, as 1097 * it has no further action. If SIGCONT is held, we 1098 * continue the process and leave the signal in 1099 * p_siglist. If the process catches SIGCONT, let it 1100 * handle the signal itself. If it isn't waiting on 1101 * an event, then it goes back to run state. 1102 * Otherwise, process goes back to sleep state. 1103 */ 1104 atomic_setbits_int(&pr->ps_flags, PS_CONTINUED); 1105 atomic_clearbits_int(&pr->ps_flags, 1106 PS_WAITED | PS_STOPPED | PS_TRAPPED); 1107 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1108 wakeparent = 1; 1109 if (action == SIG_DFL) 1110 mask = 0; 1111 if (action == SIG_CATCH) { 1112 /* Raise priority to at least PUSER. */ 1113 if (p->p_usrpri > PUSER) 1114 p->p_usrpri = PUSER; 1115 unsleep(p); 1116 setrunnable(p); 1117 goto out; 1118 } 1119 if (p->p_wchan == NULL) { 1120 setrunnable(p); 1121 goto out; 1122 } 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 process *pr = p->p_p; 1280 struct sigacts *ps = pr->ps_sigacts; 1281 sigset_t mask; 1282 1283 mtx_enter(&pr->ps_mtx); 1284 mask = sigmask(signum); 1285 sctx->sig_action = ps->ps_sigact[signum]; 1286 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1287 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1288 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1289 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1290 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1291 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1292 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1293 sctx->sig_stop = sigprop[signum] & SA_STOP && 1294 (long)sctx->sig_action == (long)SIG_DFL; 1295 if (sctx->sig_stop) { 1296 /* 1297 * If the process is a member of an orphaned 1298 * process group, ignore tty stop signals. 1299 */ 1300 if (pr->ps_flags & PS_TRACED || 1301 (pr->ps_pgrp->pg_jobc == 0 && 1302 sigprop[signum] & SA_TTYSTOP)) { 1303 sctx->sig_stop = 0; 1304 sctx->sig_ignore = 1; 1305 } 1306 } 1307 mtx_leave(&pr->ps_mtx); 1308 } 1309 1310 /* 1311 * Determine signal that should be delivered to process p, the current 1312 * process, 0 if none. 1313 * 1314 * If the current process has received a signal (should be caught or cause 1315 * termination, should interrupt current syscall), return the signal number. 1316 * Stop signals with default action are processed immediately, then cleared; 1317 * they aren't returned. This is checked after each entry to the system for 1318 * a syscall or trap. The normal call sequence is 1319 * 1320 * while (signum = cursig(curproc, &ctx, 0)) 1321 * postsig(signum, &ctx); 1322 * 1323 * Assumes that if the P_SINTR flag is set, we're holding both the 1324 * kernel and scheduler locks. 1325 */ 1326 int 1327 cursig(struct proc *p, struct sigctx *sctx, int deep) 1328 { 1329 struct process *pr = p->p_p; 1330 int signum, mask, keep = 0, prop; 1331 sigset_t ps_siglist; 1332 1333 KASSERT(p == curproc); 1334 1335 for (;;) { 1336 ps_siglist = READ_ONCE(pr->ps_siglist); 1337 membar_consumer(); 1338 mask = SIGPENDING(p); 1339 if (pr->ps_flags & PS_PPWAIT) 1340 mask &= ~STOPSIGMASK; 1341 signum = ffs(mask); 1342 if (signum == 0) /* no signal to send */ 1343 goto keep; 1344 mask = sigmask(signum); 1345 1346 /* take the signal! */ 1347 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1348 ps_siglist & ~mask) != ps_siglist) { 1349 /* lost race taking the process signal, restart */ 1350 continue; 1351 } 1352 atomic_clearbits_int(&p->p_siglist, mask); 1353 setsigctx(p, signum, sctx); 1354 1355 /* 1356 * We should see pending but ignored signals 1357 * only if PS_TRACED was on when they were posted. 1358 */ 1359 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1360 continue; 1361 1362 /* 1363 * If cursig is called while going to sleep, abort now 1364 * and stop the sleep. When the call unwinded to userret 1365 * cursig is called again and there the signal can be 1366 * handled cleanly. 1367 */ 1368 if (deep) { 1369 /* 1370 * Do not stop the thread here if multiple 1371 * signals are pending and at least one of 1372 * them would force an unwind. 1373 * 1374 * ffs() favors low numbered signals and 1375 * so stop signals may be picked up before 1376 * other pending signals. 1377 */ 1378 if (sctx->sig_stop && SIGPENDING(p)) { 1379 keep |= mask; 1380 continue; 1381 } 1382 goto keep; 1383 } 1384 1385 /* 1386 * If traced, always stop, and stay stopped until released 1387 * by the debugger. If our parent process is waiting for 1388 * us, don't hang as we could deadlock. 1389 */ 1390 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1391 signum != SIGKILL) { 1392 signum = proc_trap(p, signum); 1393 1394 mask = sigmask(signum); 1395 setsigctx(p, signum, sctx); 1396 1397 /* 1398 * If we are no longer being traced, or the parent 1399 * didn't give us a signal, or the signal is ignored, 1400 * look for more signals. 1401 */ 1402 if ((pr->ps_flags & PS_TRACED) == 0 || signum == 0 || 1403 sctx->sig_ignore) 1404 continue; 1405 1406 /* 1407 * If the new signal is being masked, look for other 1408 * signals but leave it for later. 1409 */ 1410 if ((p->p_sigmask & mask) != 0) { 1411 atomic_setbits_int(&p->p_siglist, mask); 1412 continue; 1413 } 1414 1415 } 1416 1417 prop = sigprop[signum]; 1418 1419 /* 1420 * Decide whether the signal should be returned. 1421 * Return the signal's number, or fall through 1422 * to clear it from the pending mask. 1423 */ 1424 switch ((long)sctx->sig_action) { 1425 case (long)SIG_DFL: 1426 /* 1427 * Don't take default actions on system processes. 1428 */ 1429 if (pr->ps_pid <= 1) { 1430 #ifdef DIAGNOSTIC 1431 /* 1432 * Are you sure you want to ignore SIGSEGV 1433 * in init? XXX 1434 */ 1435 printf("Process (pid %d) got signal" 1436 " %d\n", pr->ps_pid, signum); 1437 #endif 1438 break; /* == ignore */ 1439 } 1440 /* 1441 * If there is a pending stop signal to process 1442 * with default action, stop here, 1443 * then clear the signal. 1444 */ 1445 if (sctx->sig_stop) { 1446 pr->ps_xsig = signum; 1447 SCHED_LOCK(); 1448 proc_stop(p, 1); 1449 SCHED_UNLOCK(); 1450 break; 1451 } else if (prop & SA_IGNORE) { 1452 /* 1453 * Except for SIGCONT, shouldn't get here. 1454 * Default action is to ignore; drop it. 1455 */ 1456 break; /* == ignore */ 1457 } else 1458 goto keep; 1459 /* NOTREACHED */ 1460 case (long)SIG_IGN: 1461 /* 1462 * Masking above should prevent us ever trying 1463 * to take action on an ignored signal other 1464 * than SIGCONT, unless process is traced. 1465 */ 1466 if ((prop & SA_CONT) == 0 && 1467 (pr->ps_flags & PS_TRACED) == 0) 1468 printf("%s\n", __func__); 1469 break; /* == ignore */ 1470 default: 1471 /* 1472 * This signal has an action, let 1473 * postsig() process it. 1474 */ 1475 goto keep; 1476 } 1477 } 1478 /* NOTREACHED */ 1479 1480 keep: 1481 /* 1482 * if we stashed a stop signal but no other signal is pending 1483 * anymore pick the stop signal up again. 1484 */ 1485 if (keep != 0 && signum == 0) { 1486 signum = ffs(keep); 1487 setsigctx(p, signum, sctx); 1488 } 1489 /* move the signal to p_siglist for later */ 1490 atomic_setbits_int(&p->p_siglist, mask | keep); 1491 return (signum); 1492 } 1493 1494 int 1495 proc_trap(struct proc *p, int signum) 1496 { 1497 struct process *pr = p->p_p; 1498 1499 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1500 pr->ps_xsig = signum; 1501 1502 SCHED_LOCK(); 1503 atomic_setbits_int(&pr->ps_flags, PS_TRAPPED); 1504 proc_stop(p, 1); 1505 atomic_clearbits_int(&pr->ps_flags, 1506 PS_WAITED | PS_STOPPED | PS_TRAPPED); 1507 SCHED_UNLOCK(); 1508 1509 signum = pr->ps_xsig; 1510 pr->ps_xsig = 0; 1511 if ((p->p_flag & P_TRACESINGLE) == 0) 1512 single_thread_clear(p, 0); 1513 atomic_clearbits_int(&p->p_flag, P_TRACESINGLE); 1514 1515 return signum; 1516 } 1517 1518 /* 1519 * Put the argument process into the stopped state and notify the parent 1520 * via wakeup. Signals are handled elsewhere. The process must not be 1521 * on the run queue. 1522 */ 1523 void 1524 proc_stop(struct proc *p, int sw) 1525 { 1526 struct process *pr = p->p_p; 1527 1528 #ifdef MULTIPROCESSOR 1529 SCHED_ASSERT_LOCKED(); 1530 #endif 1531 /* do not stop exiting procs */ 1532 if (ISSET(p->p_flag, P_WEXIT)) 1533 return; 1534 1535 p->p_stat = SSTOP; 1536 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1537 atomic_setbits_int(&pr->ps_flags, PS_STOPPING); 1538 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1539 /* 1540 * We need this soft interrupt to be handled fast. 1541 * Extra calls to softclock don't hurt. 1542 */ 1543 softintr_schedule(proc_stop_si); 1544 if (sw) 1545 mi_switch(); 1546 } 1547 1548 /* 1549 * Called from a soft interrupt to send signals to the parents of stopped 1550 * processes. 1551 * We can't do this in proc_stop because it's called with nasty locks held 1552 * and we would need recursive scheduler lock to deal with that. 1553 */ 1554 void 1555 proc_stop_sweep(void *v) 1556 { 1557 struct process *pr; 1558 1559 LIST_FOREACH(pr, &allprocess, ps_list) { 1560 if ((pr->ps_flags & PS_STOPPING) == 0) 1561 continue; 1562 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1563 atomic_clearbits_int(&pr->ps_flags, PS_STOPPING); 1564 1565 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1566 prsignal(pr->ps_pptr, SIGCHLD); 1567 wakeup(pr->ps_pptr); 1568 } 1569 } 1570 1571 /* 1572 * Take the action for the specified signal 1573 * from the current set of pending signals. 1574 */ 1575 void 1576 postsig(struct proc *p, int signum, struct sigctx *sctx) 1577 { 1578 u_long trapno; 1579 int mask, returnmask; 1580 siginfo_t si; 1581 union sigval sigval; 1582 int code; 1583 1584 KASSERT(signum != 0); 1585 1586 mask = sigmask(signum); 1587 atomic_clearbits_int(&p->p_siglist, mask); 1588 sigval.sival_ptr = NULL; 1589 1590 if (p->p_sisig != signum) { 1591 trapno = 0; 1592 code = SI_USER; 1593 sigval.sival_ptr = NULL; 1594 } else { 1595 trapno = p->p_sitrapno; 1596 code = p->p_sicode; 1597 sigval = p->p_sigval; 1598 } 1599 initsiginfo(&si, signum, trapno, code, sigval); 1600 1601 #ifdef KTRACE 1602 if (KTRPOINT(p, KTR_PSIG)) { 1603 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1604 p->p_oldmask : p->p_sigmask, code, &si); 1605 } 1606 #endif 1607 if (sctx->sig_action == SIG_DFL) { 1608 /* 1609 * Default action, where the default is to kill 1610 * the process. (Other cases were ignored above.) 1611 */ 1612 KERNEL_LOCK(); 1613 sigexit(p, signum); 1614 /* NOTREACHED */ 1615 } else { 1616 /* 1617 * If we get here, the signal must be caught. 1618 */ 1619 #ifdef DIAGNOSTIC 1620 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1621 panic("postsig action"); 1622 #endif 1623 /* 1624 * Set the new mask value and also defer further 1625 * occurrences of this signal. 1626 * 1627 * Special case: user has done a sigpause. Here the 1628 * current mask is not of interest, but rather the 1629 * mask from before the sigpause is what we want 1630 * restored after the signal processing is completed. 1631 */ 1632 if (p->p_flag & P_SIGSUSPEND) { 1633 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1634 returnmask = p->p_oldmask; 1635 } else { 1636 returnmask = p->p_sigmask; 1637 } 1638 if (p->p_sisig == signum) { 1639 p->p_sisig = 0; 1640 p->p_sitrapno = 0; 1641 p->p_sicode = SI_USER; 1642 p->p_sigval.sival_ptr = NULL; 1643 } 1644 1645 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1646 sctx->sig_info, sctx->sig_onstack)) { 1647 KERNEL_LOCK(); 1648 sigexit(p, SIGILL); 1649 /* NOTREACHED */ 1650 } 1651 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1652 } 1653 } 1654 1655 /* 1656 * Force the current process to exit with the specified signal, dumping core 1657 * if appropriate. We bypass the normal tests for masked and caught signals, 1658 * allowing unrecoverable failures to terminate the process without changing 1659 * signal state. Mark the accounting record with the signal termination. 1660 * If dumping core, save the signal number for the debugger. Calls exit and 1661 * does not return. 1662 */ 1663 void 1664 sigexit(struct proc *p, int signum) 1665 { 1666 /* Mark process as going away */ 1667 atomic_setbits_int(&p->p_flag, P_WEXIT); 1668 1669 p->p_p->ps_acflag |= AXSIG; 1670 if (sigprop[signum] & SA_CORE) { 1671 p->p_sisig = signum; 1672 1673 /* if there are other threads, pause them */ 1674 if (P_HASSIBLING(p)) 1675 single_thread_set(p, SINGLE_UNWIND); 1676 1677 if (coredump(p) == 0) 1678 signum |= WCOREFLAG; 1679 } 1680 exit1(p, 0, signum, EXIT_NORMAL); 1681 /* NOTREACHED */ 1682 } 1683 1684 /* 1685 * Send uncatchable SIGABRT for coredump. 1686 */ 1687 void 1688 sigabort(struct proc *p) 1689 { 1690 struct sigaction sa; 1691 1692 KASSERT(p == curproc || panicstr || db_active); 1693 1694 memset(&sa, 0, sizeof sa); 1695 sa.sa_handler = SIG_DFL; 1696 setsigvec(p, SIGABRT, &sa); 1697 CLR(p->p_sigmask, sigmask(SIGABRT)); 1698 psignal(p, SIGABRT); 1699 } 1700 1701 /* 1702 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1703 * thread, and 0 otherwise. 1704 */ 1705 int 1706 sigismasked(struct proc *p, int sig) 1707 { 1708 struct process *pr = p->p_p; 1709 int rv; 1710 1711 KASSERT(p == curproc); 1712 1713 mtx_enter(&pr->ps_mtx); 1714 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1715 (p->p_sigmask & sigmask(sig)); 1716 mtx_leave(&pr->ps_mtx); 1717 1718 return !!rv; 1719 } 1720 1721 struct coredump_iostate { 1722 struct proc *io_proc; 1723 struct vnode *io_vp; 1724 struct ucred *io_cred; 1725 off_t io_offset; 1726 }; 1727 1728 /* 1729 * Dump core, into a file named "progname.core", unless the process was 1730 * setuid/setgid. 1731 */ 1732 int 1733 coredump(struct proc *p) 1734 { 1735 #ifdef SMALL_KERNEL 1736 return EPERM; 1737 #else 1738 struct process *pr = p->p_p; 1739 struct vnode *vp; 1740 struct ucred *cred = p->p_ucred; 1741 struct vmspace *vm = p->p_vmspace; 1742 struct nameidata nd; 1743 struct vattr vattr; 1744 struct coredump_iostate io; 1745 int error, len, incrash = 0; 1746 char *name; 1747 const char *dir = "/var/crash"; 1748 1749 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1750 1751 #ifdef PMAP_CHECK_COPYIN 1752 /* disable copyin checks, so we can write out text sections if needed */ 1753 p->p_vmspace->vm_map.check_copyin_count = 0; 1754 #endif 1755 1756 /* Don't dump if will exceed file size limit. */ 1757 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1758 return (EFBIG); 1759 1760 name = pool_get(&namei_pool, PR_WAITOK); 1761 1762 /* 1763 * If the process has inconsistent uids, nosuidcoredump 1764 * determines coredump placement policy. 1765 */ 1766 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1767 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1768 if (nosuidcoredump == 3) { 1769 /* 1770 * If the program directory does not exist, dumps of 1771 * that core will silently fail. 1772 */ 1773 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1774 dir, pr->ps_comm, pr->ps_pid); 1775 incrash = KERNELPATH; 1776 } else if (nosuidcoredump == 2) { 1777 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1778 dir, pr->ps_comm); 1779 incrash = KERNELPATH; 1780 } else { 1781 pool_put(&namei_pool, name); 1782 return (EPERM); 1783 } 1784 } else 1785 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1786 1787 if (len >= MAXPATHLEN) { 1788 pool_put(&namei_pool, name); 1789 return (EACCES); 1790 } 1791 1792 /* 1793 * Control the UID used to write out. The normal case uses 1794 * the real UID. If the sugid case is going to write into the 1795 * controlled directory, we do so as root. 1796 */ 1797 if (incrash == 0) { 1798 cred = crdup(cred); 1799 cred->cr_uid = cred->cr_ruid; 1800 cred->cr_gid = cred->cr_rgid; 1801 } else { 1802 if (p->p_fd->fd_rdir) { 1803 vrele(p->p_fd->fd_rdir); 1804 p->p_fd->fd_rdir = NULL; 1805 } 1806 p->p_ucred = crdup(p->p_ucred); 1807 crfree(cred); 1808 cred = p->p_ucred; 1809 crhold(cred); 1810 cred->cr_uid = 0; 1811 cred->cr_gid = 0; 1812 } 1813 1814 /* incrash should be 0 or KERNELPATH only */ 1815 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1816 1817 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1818 S_IRUSR | S_IWUSR); 1819 1820 if (error) 1821 goto out; 1822 1823 /* 1824 * Don't dump to non-regular files, files with links, or files 1825 * owned by someone else. 1826 */ 1827 vp = nd.ni_vp; 1828 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1829 VOP_UNLOCK(vp); 1830 vn_close(vp, FWRITE, cred, p); 1831 goto out; 1832 } 1833 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1834 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1835 vattr.va_uid != cred->cr_uid) { 1836 error = EACCES; 1837 VOP_UNLOCK(vp); 1838 vn_close(vp, FWRITE, cred, p); 1839 goto out; 1840 } 1841 vattr_null(&vattr); 1842 vattr.va_size = 0; 1843 VOP_SETATTR(vp, &vattr, cred, p); 1844 pr->ps_acflag |= ACORE; 1845 1846 io.io_proc = p; 1847 io.io_vp = vp; 1848 io.io_cred = cred; 1849 io.io_offset = 0; 1850 VOP_UNLOCK(vp); 1851 vref(vp); 1852 error = vn_close(vp, FWRITE, cred, p); 1853 if (error == 0) 1854 error = coredump_elf(p, &io); 1855 vrele(vp); 1856 out: 1857 crfree(cred); 1858 pool_put(&namei_pool, name); 1859 return (error); 1860 #endif 1861 } 1862 1863 #ifndef SMALL_KERNEL 1864 int 1865 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1866 int isvnode) 1867 { 1868 struct coredump_iostate *io = cookie; 1869 off_t coffset = 0; 1870 size_t csize; 1871 int chunk, error; 1872 1873 csize = len; 1874 do { 1875 if (sigmask(SIGKILL) & 1876 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1877 return (EINTR); 1878 1879 /* Rest of the loop sleeps with lock held, so... */ 1880 yield(); 1881 1882 chunk = MIN(csize, MAXPHYS); 1883 error = vn_rdwr(UIO_WRITE, io->io_vp, 1884 (caddr_t)data + coffset, chunk, 1885 io->io_offset + coffset, segflg, 1886 IO_UNIT, io->io_cred, NULL, io->io_proc); 1887 if (error && (error != EFAULT || !isvnode)) { 1888 struct process *pr = io->io_proc->p_p; 1889 1890 if (error == ENOSPC) 1891 log(LOG_ERR, 1892 "coredump of %s(%d) failed, filesystem full\n", 1893 pr->ps_comm, pr->ps_pid); 1894 else 1895 log(LOG_ERR, 1896 "coredump of %s(%d), write failed: errno %d\n", 1897 pr->ps_comm, pr->ps_pid, error); 1898 return (error); 1899 } 1900 1901 coffset += chunk; 1902 csize -= chunk; 1903 } while (csize > 0); 1904 1905 io->io_offset += len; 1906 return (0); 1907 } 1908 1909 void 1910 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1911 { 1912 struct coredump_iostate *io = cookie; 1913 1914 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1915 } 1916 1917 #endif /* !SMALL_KERNEL */ 1918 1919 /* 1920 * Nonexistent system call-- signal process (may want to handle it). 1921 * Flag error in case process won't see signal immediately (blocked or ignored). 1922 */ 1923 int 1924 sys_nosys(struct proc *p, void *v, register_t *retval) 1925 { 1926 ptsignal(p, SIGSYS, STHREAD); 1927 return (ENOSYS); 1928 } 1929 1930 int 1931 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1932 { 1933 struct sys___thrsigdivert_args /* { 1934 syscallarg(sigset_t) sigmask; 1935 syscallarg(siginfo_t *) info; 1936 syscallarg(const struct timespec *) timeout; 1937 } */ *uap = v; 1938 struct sigctx ctx; 1939 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1940 siginfo_t si; 1941 uint64_t nsecs = INFSLP; 1942 int timeinvalid = 0; 1943 int error = 0; 1944 1945 memset(&si, 0, sizeof(si)); 1946 1947 if (SCARG(uap, timeout) != NULL) { 1948 struct timespec ts; 1949 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1950 return (error); 1951 #ifdef KTRACE 1952 if (KTRPOINT(p, KTR_STRUCT)) 1953 ktrreltimespec(p, &ts); 1954 #endif 1955 if (!timespecisvalid(&ts)) 1956 timeinvalid = 1; 1957 else 1958 nsecs = TIMESPEC_TO_NSEC(&ts); 1959 } 1960 1961 dosigsuspend(p, p->p_sigmask &~ mask); 1962 for (;;) { 1963 si.si_signo = cursig(p, &ctx, 0); 1964 if (si.si_signo != 0) { 1965 sigset_t smask = sigmask(si.si_signo); 1966 if (smask & mask) { 1967 atomic_clearbits_int(&p->p_siglist, smask); 1968 error = 0; 1969 break; 1970 } 1971 } 1972 1973 /* per-POSIX, delay this error until after the above */ 1974 if (timeinvalid) 1975 error = EINVAL; 1976 /* per-POSIX, return immediately if timeout is zero-valued */ 1977 if (nsecs == 0) 1978 error = EAGAIN; 1979 1980 if (error != 0) 1981 break; 1982 1983 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1984 } 1985 1986 if (error == 0) { 1987 *retval = si.si_signo; 1988 if (SCARG(uap, info) != NULL) { 1989 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1990 #ifdef KTRACE 1991 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1992 ktrsiginfo(p, &si); 1993 #endif 1994 } 1995 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1996 /* 1997 * Restarting is wrong if there's a timeout, as it'll be 1998 * for the same interval again 1999 */ 2000 error = EINTR; 2001 } 2002 2003 return (error); 2004 } 2005 2006 void 2007 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 2008 { 2009 memset(si, 0, sizeof(*si)); 2010 2011 si->si_signo = sig; 2012 si->si_code = code; 2013 if (code == SI_USER) { 2014 si->si_value = val; 2015 } else { 2016 switch (sig) { 2017 case SIGSEGV: 2018 case SIGILL: 2019 case SIGBUS: 2020 case SIGFPE: 2021 si->si_addr = val.sival_ptr; 2022 si->si_trapno = trapno; 2023 break; 2024 case SIGXFSZ: 2025 break; 2026 } 2027 } 2028 } 2029 2030 void 2031 userret(struct proc *p) 2032 { 2033 struct sigctx ctx; 2034 int signum; 2035 2036 if (p->p_flag & P_SUSPSINGLE) 2037 single_thread_check(p, 0); 2038 2039 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 2040 if (p->p_flag & P_PROFPEND) { 2041 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 2042 psignal(p, SIGPROF); 2043 } 2044 if (p->p_flag & P_ALRMPEND) { 2045 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 2046 psignal(p, SIGVTALRM); 2047 } 2048 2049 if (SIGPENDING(p) != 0) { 2050 while ((signum = cursig(p, &ctx, 0)) != 0) 2051 postsig(p, signum, &ctx); 2052 } 2053 2054 /* 2055 * If P_SIGSUSPEND is still set here, then we still need to restore 2056 * the original sigmask before returning to userspace. Also, this 2057 * might unmask some pending signals, so we need to check a second 2058 * time for signals to post. 2059 */ 2060 if (p->p_flag & P_SIGSUSPEND) { 2061 p->p_sigmask = p->p_oldmask; 2062 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2063 2064 while ((signum = cursig(p, &ctx, 0)) != 0) 2065 postsig(p, signum, &ctx); 2066 } 2067 2068 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2069 2070 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2071 } 2072 2073 int 2074 single_thread_check_locked(struct proc *p, int deep) 2075 { 2076 struct process *pr = p->p_p; 2077 2078 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 2079 2080 if (pr->ps_single == NULL || pr->ps_single == p) 2081 return (0); 2082 2083 do { 2084 /* if we're in deep, we need to unwind to the edge */ 2085 if (deep) { 2086 if (pr->ps_flags & PS_SINGLEUNWIND) 2087 return (ERESTART); 2088 if (pr->ps_flags & PS_SINGLEEXIT) 2089 return (EINTR); 2090 } 2091 2092 if (pr->ps_flags & PS_SINGLEEXIT) { 2093 mtx_leave(&pr->ps_mtx); 2094 KERNEL_LOCK(); 2095 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2096 /* NOTREACHED */ 2097 } 2098 2099 if (--pr->ps_singlecnt == 0) 2100 wakeup(&pr->ps_singlecnt); 2101 2102 /* not exiting and don't need to unwind, so suspend */ 2103 mtx_leave(&pr->ps_mtx); 2104 2105 SCHED_LOCK(); 2106 p->p_stat = SSTOP; 2107 mi_switch(); 2108 SCHED_UNLOCK(); 2109 mtx_enter(&pr->ps_mtx); 2110 } while (pr->ps_single != NULL); 2111 2112 return (0); 2113 } 2114 2115 int 2116 single_thread_check(struct proc *p, int deep) 2117 { 2118 int error; 2119 2120 mtx_enter(&p->p_p->ps_mtx); 2121 error = single_thread_check_locked(p, deep); 2122 mtx_leave(&p->p_p->ps_mtx); 2123 2124 return error; 2125 } 2126 2127 /* 2128 * Stop other threads in the process. The mode controls how and 2129 * where the other threads should stop: 2130 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2131 * single_thread_clear()) 2132 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2133 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2134 * - SINGLE_EXIT: unwind to kernel boundary and exit 2135 */ 2136 int 2137 single_thread_set(struct proc *p, int flags) 2138 { 2139 struct process *pr = p->p_p; 2140 struct proc *q; 2141 int error, mode = flags & SINGLE_MASK; 2142 2143 KASSERT(curproc == p); 2144 2145 mtx_enter(&pr->ps_mtx); 2146 error = single_thread_check_locked(p, flags & SINGLE_DEEP); 2147 if (error) { 2148 mtx_leave(&pr->ps_mtx); 2149 return error; 2150 } 2151 2152 switch (mode) { 2153 case SINGLE_SUSPEND: 2154 break; 2155 case SINGLE_UNWIND: 2156 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2157 break; 2158 case SINGLE_EXIT: 2159 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2160 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2161 break; 2162 #ifdef DIAGNOSTIC 2163 default: 2164 panic("single_thread_mode = %d", mode); 2165 #endif 2166 } 2167 KASSERT((p->p_flag & P_SUSPSINGLE) == 0); 2168 pr->ps_single = p; 2169 pr->ps_singlecnt = pr->ps_threadcnt; 2170 2171 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2172 if (q == p) 2173 continue; 2174 SCHED_LOCK(); 2175 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2176 switch (q->p_stat) { 2177 case SSTOP: 2178 if (mode == SINGLE_EXIT) { 2179 unsleep(q); 2180 setrunnable(q); 2181 } else 2182 --pr->ps_singlecnt; 2183 break; 2184 case SSLEEP: 2185 /* if it's not interruptible, then just have to wait */ 2186 if (q->p_flag & P_SINTR) { 2187 /* merely need to suspend? just stop it */ 2188 if (mode == SINGLE_SUSPEND) { 2189 q->p_stat = SSTOP; 2190 --pr->ps_singlecnt; 2191 break; 2192 } 2193 /* need to unwind or exit, so wake it */ 2194 unsleep(q); 2195 setrunnable(q); 2196 } 2197 break; 2198 case SONPROC: 2199 signotify(q); 2200 break; 2201 case SRUN: 2202 case SIDL: 2203 case SDEAD: 2204 break; 2205 } 2206 SCHED_UNLOCK(); 2207 } 2208 2209 /* count ourself out */ 2210 --pr->ps_singlecnt; 2211 mtx_leave(&pr->ps_mtx); 2212 2213 if ((flags & SINGLE_NOWAIT) == 0) 2214 single_thread_wait(pr, 1); 2215 2216 return 0; 2217 } 2218 2219 /* 2220 * Wait for other threads to stop. If recheck is false then the function 2221 * returns non-zero if the caller needs to restart the check else 0 is 2222 * returned. If recheck is true the return value is always 0. 2223 */ 2224 int 2225 single_thread_wait(struct process *pr, int recheck) 2226 { 2227 int wait; 2228 2229 /* wait until they're all suspended */ 2230 mtx_enter(&pr->ps_mtx); 2231 while ((wait = pr->ps_singlecnt > 0)) { 2232 msleep_nsec(&pr->ps_singlecnt, &pr->ps_mtx, PWAIT, "suspend", 2233 INFSLP); 2234 if (!recheck) 2235 break; 2236 } 2237 KASSERT((pr->ps_single->p_flag & P_SUSPSINGLE) == 0); 2238 mtx_leave(&pr->ps_mtx); 2239 2240 return wait; 2241 } 2242 2243 void 2244 single_thread_clear(struct proc *p, int flag) 2245 { 2246 struct process *pr = p->p_p; 2247 struct proc *q; 2248 2249 KASSERT(pr->ps_single == p); 2250 KASSERT(curproc == p); 2251 2252 mtx_enter(&pr->ps_mtx); 2253 pr->ps_single = NULL; 2254 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2255 2256 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2257 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2258 continue; 2259 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2260 2261 /* 2262 * if the thread was only stopped for single threading 2263 * then clearing that either makes it runnable or puts 2264 * it back into some sleep queue 2265 */ 2266 SCHED_LOCK(); 2267 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2268 if (q->p_wchan == NULL) 2269 setrunnable(q); 2270 else { 2271 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2272 q->p_stat = SSLEEP; 2273 } 2274 } 2275 SCHED_UNLOCK(); 2276 } 2277 mtx_leave(&pr->ps_mtx); 2278 } 2279 2280 void 2281 sigio_del(struct sigiolst *rmlist) 2282 { 2283 struct sigio *sigio; 2284 2285 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2286 LIST_REMOVE(sigio, sio_pgsigio); 2287 crfree(sigio->sio_ucred); 2288 free(sigio, M_SIGIO, sizeof(*sigio)); 2289 } 2290 } 2291 2292 void 2293 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2294 { 2295 struct sigio *sigio; 2296 2297 MUTEX_ASSERT_LOCKED(&sigio_lock); 2298 2299 sigio = sir->sir_sigio; 2300 if (sigio != NULL) { 2301 KASSERT(sigio->sio_myref == sir); 2302 sir->sir_sigio = NULL; 2303 2304 if (sigio->sio_pgid > 0) 2305 sigio->sio_proc = NULL; 2306 else 2307 sigio->sio_pgrp = NULL; 2308 LIST_REMOVE(sigio, sio_pgsigio); 2309 2310 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2311 } 2312 } 2313 2314 void 2315 sigio_free(struct sigio_ref *sir) 2316 { 2317 struct sigiolst rmlist; 2318 2319 if (sir->sir_sigio == NULL) 2320 return; 2321 2322 LIST_INIT(&rmlist); 2323 2324 mtx_enter(&sigio_lock); 2325 sigio_unlink(sir, &rmlist); 2326 mtx_leave(&sigio_lock); 2327 2328 sigio_del(&rmlist); 2329 } 2330 2331 void 2332 sigio_freelist(struct sigiolst *sigiolst) 2333 { 2334 struct sigiolst rmlist; 2335 struct sigio *sigio; 2336 2337 if (LIST_EMPTY(sigiolst)) 2338 return; 2339 2340 LIST_INIT(&rmlist); 2341 2342 mtx_enter(&sigio_lock); 2343 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2344 sigio_unlink(sigio->sio_myref, &rmlist); 2345 mtx_leave(&sigio_lock); 2346 2347 sigio_del(&rmlist); 2348 } 2349 2350 int 2351 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2352 { 2353 struct sigiolst rmlist; 2354 struct proc *p = curproc; 2355 struct pgrp *pgrp = NULL; 2356 struct process *pr = NULL; 2357 struct sigio *sigio; 2358 int error; 2359 pid_t pgid = *(int *)data; 2360 2361 if (pgid == 0) { 2362 sigio_free(sir); 2363 return (0); 2364 } 2365 2366 if (cmd == TIOCSPGRP) { 2367 if (pgid < 0) 2368 return (EINVAL); 2369 pgid = -pgid; 2370 } 2371 2372 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2373 sigio->sio_pgid = pgid; 2374 sigio->sio_ucred = crhold(p->p_ucred); 2375 sigio->sio_myref = sir; 2376 2377 LIST_INIT(&rmlist); 2378 2379 /* 2380 * The kernel lock, and not sleeping between prfind()/pgfind() and 2381 * linking of the sigio ensure that the process or process group does 2382 * not disappear unexpectedly. 2383 */ 2384 KERNEL_LOCK(); 2385 mtx_enter(&sigio_lock); 2386 2387 if (pgid > 0) { 2388 pr = prfind(pgid); 2389 if (pr == NULL) { 2390 error = ESRCH; 2391 goto fail; 2392 } 2393 2394 /* 2395 * Policy - Don't allow a process to FSETOWN a process 2396 * in another session. 2397 * 2398 * Remove this test to allow maximum flexibility or 2399 * restrict FSETOWN to the current process or process 2400 * group for maximum safety. 2401 */ 2402 if (pr->ps_session != p->p_p->ps_session) { 2403 error = EPERM; 2404 goto fail; 2405 } 2406 2407 if ((pr->ps_flags & PS_EXITING) != 0) { 2408 error = ESRCH; 2409 goto fail; 2410 } 2411 } else /* if (pgid < 0) */ { 2412 pgrp = pgfind(-pgid); 2413 if (pgrp == NULL) { 2414 error = ESRCH; 2415 goto fail; 2416 } 2417 2418 /* 2419 * Policy - Don't allow a process to FSETOWN a process 2420 * in another session. 2421 * 2422 * Remove this test to allow maximum flexibility or 2423 * restrict FSETOWN to the current process or process 2424 * group for maximum safety. 2425 */ 2426 if (pgrp->pg_session != p->p_p->ps_session) { 2427 error = EPERM; 2428 goto fail; 2429 } 2430 } 2431 2432 if (pgid > 0) { 2433 sigio->sio_proc = pr; 2434 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2435 } else { 2436 sigio->sio_pgrp = pgrp; 2437 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2438 } 2439 2440 sigio_unlink(sir, &rmlist); 2441 sir->sir_sigio = sigio; 2442 2443 mtx_leave(&sigio_lock); 2444 KERNEL_UNLOCK(); 2445 2446 sigio_del(&rmlist); 2447 2448 return (0); 2449 2450 fail: 2451 mtx_leave(&sigio_lock); 2452 KERNEL_UNLOCK(); 2453 2454 crfree(sigio->sio_ucred); 2455 free(sigio, M_SIGIO, sizeof(*sigio)); 2456 2457 return (error); 2458 } 2459 2460 void 2461 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2462 { 2463 struct sigio *sigio; 2464 pid_t pgid = 0; 2465 2466 mtx_enter(&sigio_lock); 2467 sigio = sir->sir_sigio; 2468 if (sigio != NULL) 2469 pgid = sigio->sio_pgid; 2470 mtx_leave(&sigio_lock); 2471 2472 if (cmd == TIOCGPGRP) 2473 pgid = -pgid; 2474 2475 *(int *)data = pgid; 2476 } 2477 2478 void 2479 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2480 { 2481 struct sigiolst rmlist; 2482 struct sigio *newsigio, *sigio; 2483 2484 sigio_free(dst); 2485 2486 if (src->sir_sigio == NULL) 2487 return; 2488 2489 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2490 LIST_INIT(&rmlist); 2491 2492 mtx_enter(&sigio_lock); 2493 2494 sigio = src->sir_sigio; 2495 if (sigio == NULL) { 2496 mtx_leave(&sigio_lock); 2497 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2498 return; 2499 } 2500 2501 newsigio->sio_pgid = sigio->sio_pgid; 2502 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2503 newsigio->sio_myref = dst; 2504 if (newsigio->sio_pgid > 0) { 2505 newsigio->sio_proc = sigio->sio_proc; 2506 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2507 sio_pgsigio); 2508 } else { 2509 newsigio->sio_pgrp = sigio->sio_pgrp; 2510 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2511 sio_pgsigio); 2512 } 2513 2514 sigio_unlink(dst, &rmlist); 2515 dst->sir_sigio = newsigio; 2516 2517 mtx_leave(&sigio_lock); 2518 2519 sigio_del(&rmlist); 2520 } 2521