1 /* $OpenBSD: kern_sig.c,v 1.298 2022/06/29 10:48:22 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/resourcevar.h> 44 #include <sys/queue.h> 45 #include <sys/namei.h> 46 #include <sys/vnode.h> 47 #include <sys/event.h> 48 #include <sys/proc.h> 49 #include <sys/systm.h> 50 #include <sys/acct.h> 51 #include <sys/fcntl.h> 52 #include <sys/filedesc.h> 53 #include <sys/kernel.h> 54 #include <sys/wait.h> 55 #include <sys/ktrace.h> 56 #include <sys/stat.h> 57 #include <sys/core.h> 58 #include <sys/malloc.h> 59 #include <sys/pool.h> 60 #include <sys/ptrace.h> 61 #include <sys/sched.h> 62 #include <sys/user.h> 63 #include <sys/syslog.h> 64 #include <sys/ttycom.h> 65 #include <sys/pledge.h> 66 #include <sys/witness.h> 67 #include <sys/exec_elf.h> 68 69 #include <sys/mount.h> 70 #include <sys/syscallargs.h> 71 72 #include <uvm/uvm_extern.h> 73 #include <machine/tcb.h> 74 75 int nosuidcoredump = 1; 76 77 int filt_sigattach(struct knote *kn); 78 void filt_sigdetach(struct knote *kn); 79 int filt_signal(struct knote *kn, long hint); 80 81 const struct filterops sig_filtops = { 82 .f_flags = 0, 83 .f_attach = filt_sigattach, 84 .f_detach = filt_sigdetach, 85 .f_event = filt_signal, 86 }; 87 88 /* 89 * The array below categorizes the signals and their default actions. 90 */ 91 const int sigprop[NSIG] = { 92 0, /* unused */ 93 SA_KILL, /* SIGHUP */ 94 SA_KILL, /* SIGINT */ 95 SA_KILL|SA_CORE, /* SIGQUIT */ 96 SA_KILL|SA_CORE, /* SIGILL */ 97 SA_KILL|SA_CORE, /* SIGTRAP */ 98 SA_KILL|SA_CORE, /* SIGABRT */ 99 SA_KILL|SA_CORE, /* SIGEMT */ 100 SA_KILL|SA_CORE, /* SIGFPE */ 101 SA_KILL, /* SIGKILL */ 102 SA_KILL|SA_CORE, /* SIGBUS */ 103 SA_KILL|SA_CORE, /* SIGSEGV */ 104 SA_KILL|SA_CORE, /* SIGSYS */ 105 SA_KILL, /* SIGPIPE */ 106 SA_KILL, /* SIGALRM */ 107 SA_KILL, /* SIGTERM */ 108 SA_IGNORE, /* SIGURG */ 109 SA_STOP, /* SIGSTOP */ 110 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 111 SA_IGNORE|SA_CONT, /* SIGCONT */ 112 SA_IGNORE, /* SIGCHLD */ 113 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 114 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 115 SA_IGNORE, /* SIGIO */ 116 SA_KILL, /* SIGXCPU */ 117 SA_KILL, /* SIGXFSZ */ 118 SA_KILL, /* SIGVTALRM */ 119 SA_KILL, /* SIGPROF */ 120 SA_IGNORE, /* SIGWINCH */ 121 SA_IGNORE, /* SIGINFO */ 122 SA_KILL, /* SIGUSR1 */ 123 SA_KILL, /* SIGUSR2 */ 124 SA_IGNORE, /* SIGTHR */ 125 }; 126 127 #define CONTSIGMASK (sigmask(SIGCONT)) 128 #define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 129 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 130 131 void setsigvec(struct proc *, int, struct sigaction *); 132 133 void proc_stop(struct proc *p, int); 134 void proc_stop_sweep(void *); 135 void *proc_stop_si; 136 137 void setsigctx(struct proc *, int, struct sigctx *); 138 void postsig_done(struct proc *, int, sigset_t, int); 139 void postsig(struct proc *, int, struct sigctx *); 140 int cansignal(struct proc *, struct process *, int); 141 142 struct pool sigacts_pool; /* memory pool for sigacts structures */ 143 144 void sigio_del(struct sigiolst *); 145 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 146 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 147 148 /* 149 * Can thread p, send the signal signum to process qr? 150 */ 151 int 152 cansignal(struct proc *p, struct process *qr, int signum) 153 { 154 struct process *pr = p->p_p; 155 struct ucred *uc = p->p_ucred; 156 struct ucred *quc = qr->ps_ucred; 157 158 if (uc->cr_uid == 0) 159 return (1); /* root can always signal */ 160 161 if (pr == qr) 162 return (1); /* process can always signal itself */ 163 164 /* optimization: if the same creds then the tests below will pass */ 165 if (uc == quc) 166 return (1); 167 168 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 169 return (1); /* SIGCONT in session */ 170 171 /* 172 * Using kill(), only certain signals can be sent to setugid 173 * child processes 174 */ 175 if (qr->ps_flags & PS_SUGID) { 176 switch (signum) { 177 case 0: 178 case SIGKILL: 179 case SIGINT: 180 case SIGTERM: 181 case SIGALRM: 182 case SIGSTOP: 183 case SIGTTIN: 184 case SIGTTOU: 185 case SIGTSTP: 186 case SIGHUP: 187 case SIGUSR1: 188 case SIGUSR2: 189 if (uc->cr_ruid == quc->cr_ruid || 190 uc->cr_uid == quc->cr_ruid) 191 return (1); 192 } 193 return (0); 194 } 195 196 if (uc->cr_ruid == quc->cr_ruid || 197 uc->cr_ruid == quc->cr_svuid || 198 uc->cr_uid == quc->cr_ruid || 199 uc->cr_uid == quc->cr_svuid) 200 return (1); 201 return (0); 202 } 203 204 /* 205 * Initialize signal-related data structures. 206 */ 207 void 208 signal_init(void) 209 { 210 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 211 NULL); 212 if (proc_stop_si == NULL) 213 panic("signal_init failed to register softintr"); 214 215 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 216 PR_WAITOK, "sigapl", NULL); 217 } 218 219 /* 220 * Initialize a new sigaltstack structure. 221 */ 222 void 223 sigstkinit(struct sigaltstack *ss) 224 { 225 ss->ss_flags = SS_DISABLE; 226 ss->ss_size = 0; 227 ss->ss_sp = NULL; 228 } 229 230 /* 231 * Create an initial sigacts structure, using the same signal state 232 * as pr. 233 */ 234 struct sigacts * 235 sigactsinit(struct process *pr) 236 { 237 struct sigacts *ps; 238 239 ps = pool_get(&sigacts_pool, PR_WAITOK); 240 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 241 return (ps); 242 } 243 244 /* 245 * Release a sigacts structure. 246 */ 247 void 248 sigactsfree(struct sigacts *ps) 249 { 250 pool_put(&sigacts_pool, ps); 251 } 252 253 int 254 sys_sigaction(struct proc *p, void *v, register_t *retval) 255 { 256 struct sys_sigaction_args /* { 257 syscallarg(int) signum; 258 syscallarg(const struct sigaction *) nsa; 259 syscallarg(struct sigaction *) osa; 260 } */ *uap = v; 261 struct sigaction vec; 262 #ifdef KTRACE 263 struct sigaction ovec; 264 #endif 265 struct sigaction *sa; 266 const struct sigaction *nsa; 267 struct sigaction *osa; 268 struct sigacts *ps = p->p_p->ps_sigacts; 269 int signum; 270 int bit, error; 271 272 signum = SCARG(uap, signum); 273 nsa = SCARG(uap, nsa); 274 osa = SCARG(uap, osa); 275 276 if (signum <= 0 || signum >= NSIG || 277 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 278 return (EINVAL); 279 sa = &vec; 280 if (osa) { 281 mtx_enter(&p->p_p->ps_mtx); 282 sa->sa_handler = ps->ps_sigact[signum]; 283 sa->sa_mask = ps->ps_catchmask[signum]; 284 bit = sigmask(signum); 285 sa->sa_flags = 0; 286 if ((ps->ps_sigonstack & bit) != 0) 287 sa->sa_flags |= SA_ONSTACK; 288 if ((ps->ps_sigintr & bit) == 0) 289 sa->sa_flags |= SA_RESTART; 290 if ((ps->ps_sigreset & bit) != 0) 291 sa->sa_flags |= SA_RESETHAND; 292 if ((ps->ps_siginfo & bit) != 0) 293 sa->sa_flags |= SA_SIGINFO; 294 if (signum == SIGCHLD) { 295 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 296 sa->sa_flags |= SA_NOCLDSTOP; 297 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 298 sa->sa_flags |= SA_NOCLDWAIT; 299 } 300 mtx_leave(&p->p_p->ps_mtx); 301 if ((sa->sa_mask & bit) == 0) 302 sa->sa_flags |= SA_NODEFER; 303 sa->sa_mask &= ~bit; 304 error = copyout(sa, osa, sizeof (vec)); 305 if (error) 306 return (error); 307 #ifdef KTRACE 308 if (KTRPOINT(p, KTR_STRUCT)) 309 ovec = vec; 310 #endif 311 } 312 if (nsa) { 313 error = copyin(nsa, sa, sizeof (vec)); 314 if (error) 315 return (error); 316 #ifdef KTRACE 317 if (KTRPOINT(p, KTR_STRUCT)) 318 ktrsigaction(p, sa); 319 #endif 320 setsigvec(p, signum, sa); 321 } 322 #ifdef KTRACE 323 if (osa && KTRPOINT(p, KTR_STRUCT)) 324 ktrsigaction(p, &ovec); 325 #endif 326 return (0); 327 } 328 329 void 330 setsigvec(struct proc *p, int signum, struct sigaction *sa) 331 { 332 struct sigacts *ps = p->p_p->ps_sigacts; 333 int bit; 334 335 bit = sigmask(signum); 336 337 mtx_enter(&p->p_p->ps_mtx); 338 ps->ps_sigact[signum] = sa->sa_handler; 339 if ((sa->sa_flags & SA_NODEFER) == 0) 340 sa->sa_mask |= sigmask(signum); 341 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 342 if (signum == SIGCHLD) { 343 if (sa->sa_flags & SA_NOCLDSTOP) 344 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 345 else 346 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 347 /* 348 * If the SA_NOCLDWAIT flag is set or the handler 349 * is SIG_IGN we reparent the dying child to PID 1 350 * (init) which will reap the zombie. Because we use 351 * init to do our dirty work we never set SAS_NOCLDWAIT 352 * for PID 1. 353 * XXX exit1 rework means this is unnecessary? 354 */ 355 if (initprocess->ps_sigacts != ps && 356 ((sa->sa_flags & SA_NOCLDWAIT) || 357 sa->sa_handler == SIG_IGN)) 358 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 359 else 360 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 361 } 362 if ((sa->sa_flags & SA_RESETHAND) != 0) 363 ps->ps_sigreset |= bit; 364 else 365 ps->ps_sigreset &= ~bit; 366 if ((sa->sa_flags & SA_SIGINFO) != 0) 367 ps->ps_siginfo |= bit; 368 else 369 ps->ps_siginfo &= ~bit; 370 if ((sa->sa_flags & SA_RESTART) == 0) 371 ps->ps_sigintr |= bit; 372 else 373 ps->ps_sigintr &= ~bit; 374 if ((sa->sa_flags & SA_ONSTACK) != 0) 375 ps->ps_sigonstack |= bit; 376 else 377 ps->ps_sigonstack &= ~bit; 378 /* 379 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 380 * and for signals set to SIG_DFL where the default is to ignore. 381 * However, don't put SIGCONT in ps_sigignore, 382 * as we have to restart the process. 383 */ 384 if (sa->sa_handler == SIG_IGN || 385 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 386 atomic_clearbits_int(&p->p_siglist, bit); 387 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 388 if (signum != SIGCONT) 389 ps->ps_sigignore |= bit; /* easier in psignal */ 390 ps->ps_sigcatch &= ~bit; 391 } else { 392 ps->ps_sigignore &= ~bit; 393 if (sa->sa_handler == SIG_DFL) 394 ps->ps_sigcatch &= ~bit; 395 else 396 ps->ps_sigcatch |= bit; 397 } 398 mtx_leave(&p->p_p->ps_mtx); 399 } 400 401 /* 402 * Initialize signal state for process 0; 403 * set to ignore signals that are ignored by default. 404 */ 405 void 406 siginit(struct sigacts *ps) 407 { 408 int i; 409 410 for (i = 0; i < NSIG; i++) 411 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 412 ps->ps_sigignore |= sigmask(i); 413 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 414 } 415 416 /* 417 * Reset signals for an exec by the specified thread. 418 */ 419 void 420 execsigs(struct proc *p) 421 { 422 struct sigacts *ps; 423 int nc, mask; 424 425 ps = p->p_p->ps_sigacts; 426 mtx_enter(&p->p_p->ps_mtx); 427 428 /* 429 * Reset caught signals. Held signals remain held 430 * through p_sigmask (unless they were caught, 431 * and are now ignored by default). 432 */ 433 while (ps->ps_sigcatch) { 434 nc = ffs((long)ps->ps_sigcatch); 435 mask = sigmask(nc); 436 ps->ps_sigcatch &= ~mask; 437 if (sigprop[nc] & SA_IGNORE) { 438 if (nc != SIGCONT) 439 ps->ps_sigignore |= mask; 440 atomic_clearbits_int(&p->p_siglist, mask); 441 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 442 } 443 ps->ps_sigact[nc] = SIG_DFL; 444 } 445 /* 446 * Reset stack state to the user stack. 447 * Clear set of signals caught on the signal stack. 448 */ 449 sigstkinit(&p->p_sigstk); 450 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 451 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 452 ps->ps_sigact[SIGCHLD] = SIG_DFL; 453 mtx_leave(&p->p_p->ps_mtx); 454 } 455 456 /* 457 * Manipulate signal mask. 458 * Note that we receive new mask, not pointer, 459 * and return old mask as return value; 460 * the library stub does the rest. 461 */ 462 int 463 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 464 { 465 struct sys_sigprocmask_args /* { 466 syscallarg(int) how; 467 syscallarg(sigset_t) mask; 468 } */ *uap = v; 469 int error = 0; 470 sigset_t mask; 471 472 KASSERT(p == curproc); 473 474 *retval = p->p_sigmask; 475 mask = SCARG(uap, mask) &~ sigcantmask; 476 477 switch (SCARG(uap, how)) { 478 case SIG_BLOCK: 479 atomic_setbits_int(&p->p_sigmask, mask); 480 break; 481 case SIG_UNBLOCK: 482 atomic_clearbits_int(&p->p_sigmask, mask); 483 break; 484 case SIG_SETMASK: 485 p->p_sigmask = mask; 486 break; 487 default: 488 error = EINVAL; 489 break; 490 } 491 return (error); 492 } 493 494 int 495 sys_sigpending(struct proc *p, void *v, register_t *retval) 496 { 497 *retval = p->p_siglist | p->p_p->ps_siglist; 498 return (0); 499 } 500 501 /* 502 * Temporarily replace calling proc's signal mask for the duration of a 503 * system call. Original signal mask will be restored by userret(). 504 */ 505 void 506 dosigsuspend(struct proc *p, sigset_t newmask) 507 { 508 KASSERT(p == curproc); 509 510 p->p_oldmask = p->p_sigmask; 511 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 512 p->p_sigmask = newmask; 513 } 514 515 /* 516 * Suspend thread until signal, providing mask to be set 517 * in the meantime. Note nonstandard calling convention: 518 * libc stub passes mask, not pointer, to save a copyin. 519 */ 520 int 521 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 522 { 523 struct sys_sigsuspend_args /* { 524 syscallarg(int) mask; 525 } */ *uap = v; 526 527 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 528 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 529 continue; 530 /* always return EINTR rather than ERESTART... */ 531 return (EINTR); 532 } 533 534 int 535 sigonstack(size_t stack) 536 { 537 const struct sigaltstack *ss = &curproc->p_sigstk; 538 539 return (ss->ss_flags & SS_DISABLE ? 0 : 540 (stack - (size_t)ss->ss_sp < ss->ss_size)); 541 } 542 543 int 544 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 545 { 546 struct sys_sigaltstack_args /* { 547 syscallarg(const struct sigaltstack *) nss; 548 syscallarg(struct sigaltstack *) oss; 549 } */ *uap = v; 550 struct sigaltstack ss; 551 const struct sigaltstack *nss; 552 struct sigaltstack *oss; 553 int onstack = sigonstack(PROC_STACK(p)); 554 int error; 555 556 nss = SCARG(uap, nss); 557 oss = SCARG(uap, oss); 558 559 if (oss != NULL) { 560 ss = p->p_sigstk; 561 if (onstack) 562 ss.ss_flags |= SS_ONSTACK; 563 if ((error = copyout(&ss, oss, sizeof(ss)))) 564 return (error); 565 } 566 if (nss == NULL) 567 return (0); 568 error = copyin(nss, &ss, sizeof(ss)); 569 if (error) 570 return (error); 571 if (onstack) 572 return (EPERM); 573 if (ss.ss_flags & ~SS_DISABLE) 574 return (EINVAL); 575 if (ss.ss_flags & SS_DISABLE) { 576 p->p_sigstk.ss_flags = ss.ss_flags; 577 return (0); 578 } 579 if (ss.ss_size < MINSIGSTKSZ) 580 return (ENOMEM); 581 582 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 583 if (error) 584 return (error); 585 586 p->p_sigstk = ss; 587 return (0); 588 } 589 590 int 591 sys_kill(struct proc *cp, void *v, register_t *retval) 592 { 593 struct sys_kill_args /* { 594 syscallarg(int) pid; 595 syscallarg(int) signum; 596 } */ *uap = v; 597 struct process *pr; 598 int pid = SCARG(uap, pid); 599 int signum = SCARG(uap, signum); 600 int error; 601 int zombie = 0; 602 603 if ((error = pledge_kill(cp, pid)) != 0) 604 return (error); 605 if (((u_int)signum) >= NSIG) 606 return (EINVAL); 607 if (pid > 0) { 608 if ((pr = prfind(pid)) == NULL) { 609 if ((pr = zombiefind(pid)) == NULL) 610 return (ESRCH); 611 else 612 zombie = 1; 613 } 614 if (!cansignal(cp, pr, signum)) 615 return (EPERM); 616 617 /* kill single process */ 618 if (signum && !zombie) 619 prsignal(pr, signum); 620 return (0); 621 } 622 switch (pid) { 623 case -1: /* broadcast signal */ 624 return (killpg1(cp, signum, 0, 1)); 625 case 0: /* signal own process group */ 626 return (killpg1(cp, signum, 0, 0)); 627 default: /* negative explicit process group */ 628 return (killpg1(cp, signum, -pid, 0)); 629 } 630 } 631 632 int 633 sys_thrkill(struct proc *cp, void *v, register_t *retval) 634 { 635 struct sys_thrkill_args /* { 636 syscallarg(pid_t) tid; 637 syscallarg(int) signum; 638 syscallarg(void *) tcb; 639 } */ *uap = v; 640 struct proc *p; 641 int tid = SCARG(uap, tid); 642 int signum = SCARG(uap, signum); 643 void *tcb; 644 645 if (((u_int)signum) >= NSIG) 646 return (EINVAL); 647 if (tid > THREAD_PID_OFFSET) { 648 if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL) 649 return (ESRCH); 650 651 /* can only kill threads in the same process */ 652 if (p->p_p != cp->p_p) 653 return (ESRCH); 654 } else if (tid == 0) 655 p = cp; 656 else 657 return (EINVAL); 658 659 /* optionally require the target thread to have the given tcb addr */ 660 tcb = SCARG(uap, tcb); 661 if (tcb != NULL && tcb != TCB_GET(p)) 662 return (ESRCH); 663 664 if (signum) 665 ptsignal(p, signum, STHREAD); 666 return (0); 667 } 668 669 /* 670 * Common code for kill process group/broadcast kill. 671 * cp is calling process. 672 */ 673 int 674 killpg1(struct proc *cp, int signum, int pgid, int all) 675 { 676 struct process *pr; 677 struct pgrp *pgrp; 678 int nfound = 0; 679 680 if (all) { 681 /* 682 * broadcast 683 */ 684 LIST_FOREACH(pr, &allprocess, ps_list) { 685 if (pr->ps_pid <= 1 || 686 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 687 pr == cp->p_p || !cansignal(cp, pr, signum)) 688 continue; 689 nfound++; 690 if (signum) 691 prsignal(pr, signum); 692 } 693 } else { 694 if (pgid == 0) 695 /* 696 * zero pgid means send to my process group. 697 */ 698 pgrp = cp->p_p->ps_pgrp; 699 else { 700 pgrp = pgfind(pgid); 701 if (pgrp == NULL) 702 return (ESRCH); 703 } 704 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 705 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 706 !cansignal(cp, pr, signum)) 707 continue; 708 nfound++; 709 if (signum) 710 prsignal(pr, signum); 711 } 712 } 713 return (nfound ? 0 : ESRCH); 714 } 715 716 #define CANDELIVER(uid, euid, pr) \ 717 (euid == 0 || \ 718 (uid) == (pr)->ps_ucred->cr_ruid || \ 719 (uid) == (pr)->ps_ucred->cr_svuid || \ 720 (uid) == (pr)->ps_ucred->cr_uid || \ 721 (euid) == (pr)->ps_ucred->cr_ruid || \ 722 (euid) == (pr)->ps_ucred->cr_svuid || \ 723 (euid) == (pr)->ps_ucred->cr_uid) 724 725 #define CANSIGIO(cr, pr) \ 726 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 727 728 /* 729 * Send a signal to a process group. If checktty is 1, 730 * limit to members which have a controlling terminal. 731 */ 732 void 733 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 734 { 735 struct process *pr; 736 737 if (pgrp) 738 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 739 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 740 prsignal(pr, signum); 741 } 742 743 /* 744 * Send a SIGIO or SIGURG signal to a process or process group using stored 745 * credentials rather than those of the current process. 746 */ 747 void 748 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 749 { 750 struct process *pr; 751 struct sigio *sigio; 752 753 if (sir->sir_sigio == NULL) 754 return; 755 756 KERNEL_LOCK(); 757 mtx_enter(&sigio_lock); 758 sigio = sir->sir_sigio; 759 if (sigio == NULL) 760 goto out; 761 if (sigio->sio_pgid > 0) { 762 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 763 prsignal(sigio->sio_proc, sig); 764 } else if (sigio->sio_pgid < 0) { 765 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 766 if (CANSIGIO(sigio->sio_ucred, pr) && 767 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 768 prsignal(pr, sig); 769 } 770 } 771 out: 772 mtx_leave(&sigio_lock); 773 KERNEL_UNLOCK(); 774 } 775 776 /* 777 * Recalculate the signal mask and reset the signal disposition after 778 * usermode frame for delivery is formed. 779 */ 780 void 781 postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 782 { 783 p->p_ru.ru_nsignals++; 784 atomic_setbits_int(&p->p_sigmask, catchmask); 785 if (reset != 0) { 786 sigset_t mask = sigmask(signum); 787 struct sigacts *ps = p->p_p->ps_sigacts; 788 789 mtx_enter(&p->p_p->ps_mtx); 790 ps->ps_sigcatch &= ~mask; 791 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 792 ps->ps_sigignore |= mask; 793 ps->ps_sigact[signum] = SIG_DFL; 794 mtx_leave(&p->p_p->ps_mtx); 795 } 796 } 797 798 /* 799 * Send a signal caused by a trap to the current thread 800 * If it will be caught immediately, deliver it with correct code. 801 * Otherwise, post it normally. 802 */ 803 void 804 trapsignal(struct proc *p, int signum, u_long trapno, int code, 805 union sigval sigval) 806 { 807 struct process *pr = p->p_p; 808 struct sigctx ctx; 809 int mask; 810 811 switch (signum) { 812 case SIGILL: 813 case SIGBUS: 814 case SIGSEGV: 815 pr->ps_acflag |= ATRAP; 816 break; 817 } 818 819 mask = sigmask(signum); 820 setsigctx(p, signum, &ctx); 821 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 822 (p->p_sigmask & mask) == 0) { 823 siginfo_t si; 824 825 initsiginfo(&si, signum, trapno, code, sigval); 826 #ifdef KTRACE 827 if (KTRPOINT(p, KTR_PSIG)) { 828 ktrpsig(p, signum, ctx.sig_action, 829 p->p_sigmask, code, &si); 830 } 831 #endif 832 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 833 ctx.sig_info, ctx.sig_onstack)) { 834 KERNEL_LOCK(); 835 sigexit(p, SIGILL); 836 /* NOTREACHED */ 837 } 838 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 839 } else { 840 p->p_sisig = signum; 841 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 842 p->p_sicode = code; 843 p->p_sigval = sigval; 844 845 /* 846 * If traced, stop if signal is masked, and stay stopped 847 * until released by the debugger. If our parent process 848 * is waiting for us, don't hang as we could deadlock. 849 */ 850 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 851 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 852 int s; 853 854 single_thread_set(p, SINGLE_SUSPEND, 0); 855 pr->ps_xsig = signum; 856 857 SCHED_LOCK(s); 858 proc_stop(p, 1); 859 SCHED_UNLOCK(s); 860 861 signum = pr->ps_xsig; 862 single_thread_clear(p, 0); 863 864 /* 865 * If we are no longer being traced, or the parent 866 * didn't give us a signal, skip sending the signal. 867 */ 868 if ((pr->ps_flags & PS_TRACED) == 0 || 869 signum == 0) 870 return; 871 872 /* update signal info */ 873 p->p_sisig = signum; 874 mask = sigmask(signum); 875 } 876 877 /* 878 * Signals like SIGBUS and SIGSEGV should not, when 879 * generated by the kernel, be ignorable or blockable. 880 * If it is and we're not being traced, then just kill 881 * the process. 882 * After vfs_shutdown(9), init(8) cannot receive signals 883 * because new code pages of the signal handler cannot be 884 * mapped from halted storage. init(8) may not die or the 885 * kernel panics. Better loop between signal handler and 886 * page fault trap until the machine is halted. 887 */ 888 if ((pr->ps_flags & PS_TRACED) == 0 && 889 (sigprop[signum] & SA_KILL) && 890 ((p->p_sigmask & mask) || ctx.sig_ignore) && 891 pr->ps_pid != 1) { 892 KERNEL_LOCK(); 893 sigexit(p, signum); 894 /* NOTREACHED */ 895 } 896 KERNEL_LOCK(); 897 ptsignal(p, signum, STHREAD); 898 KERNEL_UNLOCK(); 899 } 900 } 901 902 /* 903 * Send the signal to the process. If the signal has an action, the action 904 * is usually performed by the target process rather than the caller; we add 905 * the signal to the set of pending signals for the process. 906 * 907 * Exceptions: 908 * o When a stop signal is sent to a sleeping process that takes the 909 * default action, the process is stopped without awakening it. 910 * o SIGCONT restarts stopped processes (or puts them back to sleep) 911 * regardless of the signal action (eg, blocked or ignored). 912 * 913 * Other ignored signals are discarded immediately. 914 */ 915 void 916 psignal(struct proc *p, int signum) 917 { 918 ptsignal(p, signum, SPROCESS); 919 } 920 921 /* 922 * type = SPROCESS process signal, can be diverted (sigwait()) 923 * type = STHREAD thread signal, but should be propagated if unhandled 924 * type = SPROPAGATED propagated to this thread, so don't propagate again 925 */ 926 void 927 ptsignal(struct proc *p, int signum, enum signal_type type) 928 { 929 int s, prop; 930 sig_t action; 931 int mask; 932 int *siglist; 933 struct process *pr = p->p_p; 934 struct proc *q; 935 int wakeparent = 0; 936 937 KERNEL_ASSERT_LOCKED(); 938 939 #ifdef DIAGNOSTIC 940 if ((u_int)signum >= NSIG || signum == 0) 941 panic("psignal signal number"); 942 #endif 943 944 /* Ignore signal if the target process is exiting */ 945 if (pr->ps_flags & PS_EXITING) 946 return; 947 948 mask = sigmask(signum); 949 950 if (type == SPROCESS) { 951 /* Accept SIGKILL to coredumping processes */ 952 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 953 atomic_setbits_int(&pr->ps_siglist, mask); 954 return; 955 } 956 957 /* 958 * If the current thread can process the signal 959 * immediately (it's unblocked) then have it take it. 960 */ 961 q = curproc; 962 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 963 (q->p_sigmask & mask) == 0) 964 p = q; 965 else { 966 /* 967 * A process-wide signal can be diverted to a 968 * different thread that's in sigwait() for this 969 * signal. If there isn't such a thread, then 970 * pick a thread that doesn't have it blocked so 971 * that the stop/kill consideration isn't 972 * delayed. Otherwise, mark it pending on the 973 * main thread. 974 */ 975 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 976 /* ignore exiting threads */ 977 if (q->p_flag & P_WEXIT) 978 continue; 979 980 /* skip threads that have the signal blocked */ 981 if ((q->p_sigmask & mask) != 0) 982 continue; 983 984 /* okay, could send to this thread */ 985 p = q; 986 987 /* 988 * sigsuspend, sigwait, ppoll/pselect, etc? 989 * Definitely go to this thread, as it's 990 * already blocked in the kernel. 991 */ 992 if (q->p_flag & P_SIGSUSPEND) 993 break; 994 } 995 } 996 } 997 998 if (type != SPROPAGATED) 999 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 1000 1001 prop = sigprop[signum]; 1002 1003 /* 1004 * If proc is traced, always give parent a chance. 1005 */ 1006 if (pr->ps_flags & PS_TRACED) { 1007 action = SIG_DFL; 1008 } else { 1009 sigset_t sigcatch, sigignore; 1010 1011 /* 1012 * If the signal is being ignored, 1013 * then we forget about it immediately. 1014 * (Note: we don't set SIGCONT in ps_sigignore, 1015 * and if it is set to SIG_IGN, 1016 * action will be SIG_DFL here.) 1017 */ 1018 mtx_enter(&pr->ps_mtx); 1019 sigignore = pr->ps_sigacts->ps_sigignore; 1020 sigcatch = pr->ps_sigacts->ps_sigcatch; 1021 mtx_leave(&pr->ps_mtx); 1022 1023 if (sigignore & mask) 1024 return; 1025 if (p->p_sigmask & mask) { 1026 action = SIG_HOLD; 1027 } else if (sigcatch & mask) { 1028 action = SIG_CATCH; 1029 } else { 1030 action = SIG_DFL; 1031 1032 if (prop & SA_KILL && pr->ps_nice > NZERO) 1033 pr->ps_nice = NZERO; 1034 1035 /* 1036 * If sending a tty stop signal to a member of an 1037 * orphaned process group, discard the signal here if 1038 * the action is default; don't stop the process below 1039 * if sleeping, and don't clear any pending SIGCONT. 1040 */ 1041 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1042 return; 1043 } 1044 } 1045 /* 1046 * If delivered to process, mark as pending there. Continue and stop 1047 * signals will be propagated to all threads. So they are always 1048 * marked at thread level. 1049 */ 1050 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1051 if (prop & SA_CONT) { 1052 siglist = &p->p_siglist; 1053 atomic_clearbits_int(siglist, STOPSIGMASK); 1054 } 1055 if (prop & SA_STOP) { 1056 siglist = &p->p_siglist; 1057 atomic_clearbits_int(siglist, CONTSIGMASK); 1058 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1059 } 1060 1061 /* 1062 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1063 */ 1064 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1065 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1066 if (q != p) 1067 ptsignal(q, signum, SPROPAGATED); 1068 1069 /* 1070 * Defer further processing for signals which are held, 1071 * except that stopped processes must be continued by SIGCONT. 1072 */ 1073 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || 1074 p->p_stat != SSTOP)) { 1075 atomic_setbits_int(siglist, mask); 1076 return; 1077 } 1078 1079 SCHED_LOCK(s); 1080 1081 switch (p->p_stat) { 1082 1083 case SSLEEP: 1084 /* 1085 * If process is sleeping uninterruptibly 1086 * we can't interrupt the sleep... the signal will 1087 * be noticed when the process returns through 1088 * trap() or syscall(). 1089 */ 1090 if ((p->p_flag & P_SINTR) == 0) 1091 goto out; 1092 /* 1093 * Process is sleeping and traced... make it runnable 1094 * so it can discover the signal in cursig() and stop 1095 * for the parent. 1096 */ 1097 if (pr->ps_flags & PS_TRACED) 1098 goto run; 1099 /* 1100 * If SIGCONT is default (or ignored) and process is 1101 * asleep, we are finished; the process should not 1102 * be awakened. 1103 */ 1104 if ((prop & SA_CONT) && action == SIG_DFL) { 1105 mask = 0; 1106 goto out; 1107 } 1108 /* 1109 * When a sleeping process receives a stop 1110 * signal, process immediately if possible. 1111 */ 1112 if ((prop & SA_STOP) && action == SIG_DFL) { 1113 /* 1114 * If a child holding parent blocked, 1115 * stopping could cause deadlock. 1116 */ 1117 if (pr->ps_flags & PS_PPWAIT) 1118 goto out; 1119 mask = 0; 1120 pr->ps_xsig = signum; 1121 proc_stop(p, 0); 1122 goto out; 1123 } 1124 /* 1125 * All other (caught or default) signals 1126 * cause the process to run. 1127 */ 1128 goto runfast; 1129 /* NOTREACHED */ 1130 1131 case SSTOP: 1132 /* 1133 * If traced process is already stopped, 1134 * then no further action is necessary. 1135 */ 1136 if (pr->ps_flags & PS_TRACED) 1137 goto out; 1138 1139 /* 1140 * Kill signal always sets processes running. 1141 */ 1142 if (signum == SIGKILL) { 1143 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1144 goto runfast; 1145 } 1146 1147 if (prop & SA_CONT) { 1148 /* 1149 * If SIGCONT is default (or ignored), we continue the 1150 * process but don't leave the signal in p_siglist, as 1151 * it has no further action. If SIGCONT is held, we 1152 * continue the process and leave the signal in 1153 * p_siglist. If the process catches SIGCONT, let it 1154 * handle the signal itself. If it isn't waiting on 1155 * an event, then it goes back to run state. 1156 * Otherwise, process goes back to sleep state. 1157 */ 1158 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1159 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1160 wakeparent = 1; 1161 if (action == SIG_DFL) 1162 atomic_clearbits_int(siglist, mask); 1163 if (action == SIG_CATCH) 1164 goto runfast; 1165 if (p->p_wchan == NULL) 1166 goto run; 1167 p->p_stat = SSLEEP; 1168 goto out; 1169 } 1170 1171 if (prop & SA_STOP) { 1172 /* 1173 * Already stopped, don't need to stop again. 1174 * (If we did the shell could get confused.) 1175 */ 1176 mask = 0; 1177 goto out; 1178 } 1179 1180 /* 1181 * If process is sleeping interruptibly, then simulate a 1182 * wakeup so that when it is continued, it will be made 1183 * runnable and can look at the signal. But don't make 1184 * the process runnable, leave it stopped. 1185 */ 1186 if (p->p_flag & P_SINTR) 1187 unsleep(p); 1188 goto out; 1189 1190 case SONPROC: 1191 /* set siglist before issuing the ast */ 1192 atomic_setbits_int(siglist, mask); 1193 mask = 0; 1194 signotify(p); 1195 /* FALLTHROUGH */ 1196 default: 1197 /* 1198 * SRUN, SIDL, SDEAD do nothing with the signal, 1199 * other than kicking ourselves if we are running. 1200 * It will either never be noticed, or noticed very soon. 1201 */ 1202 goto out; 1203 } 1204 /* NOTREACHED */ 1205 1206 runfast: 1207 /* 1208 * Raise priority to at least PUSER. 1209 */ 1210 if (p->p_usrpri > PUSER) 1211 p->p_usrpri = PUSER; 1212 run: 1213 setrunnable(p); 1214 out: 1215 /* finally adjust siglist */ 1216 if (mask) 1217 atomic_setbits_int(siglist, mask); 1218 SCHED_UNLOCK(s); 1219 if (wakeparent) 1220 wakeup(pr->ps_pptr); 1221 } 1222 1223 /* fill the signal context which should be used by postsig() and issignal() */ 1224 void 1225 setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1226 { 1227 struct sigacts *ps = p->p_p->ps_sigacts; 1228 sigset_t mask; 1229 1230 mtx_enter(&p->p_p->ps_mtx); 1231 mask = sigmask(signum); 1232 sctx->sig_action = ps->ps_sigact[signum]; 1233 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1234 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1235 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1236 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1237 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1238 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1239 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1240 mtx_leave(&p->p_p->ps_mtx); 1241 } 1242 1243 /* 1244 * Determine signal that should be delivered to process p, the current 1245 * process, 0 if none. 1246 * 1247 * If the current process has received a signal (should be caught or cause 1248 * termination, should interrupt current syscall), return the signal number. 1249 * Stop signals with default action are processed immediately, then cleared; 1250 * they aren't returned. This is checked after each entry to the system for 1251 * a syscall or trap. The normal call sequence is 1252 * 1253 * while (signum = cursig(curproc, &ctx)) 1254 * postsig(signum, &ctx); 1255 * 1256 * Assumes that if the P_SINTR flag is set, we're holding both the 1257 * kernel and scheduler locks. 1258 */ 1259 int 1260 cursig(struct proc *p, struct sigctx *sctx) 1261 { 1262 struct process *pr = p->p_p; 1263 int signum, mask, prop; 1264 int dolock = (p->p_flag & P_SINTR) == 0; 1265 sigset_t ps_siglist; 1266 int s; 1267 1268 KASSERT(p == curproc); 1269 1270 for (;;) { 1271 ps_siglist = READ_ONCE(pr->ps_siglist); 1272 membar_consumer(); 1273 mask = SIGPENDING(p); 1274 if (pr->ps_flags & PS_PPWAIT) 1275 mask &= ~STOPSIGMASK; 1276 if (mask == 0) /* no signal to send */ 1277 return (0); 1278 signum = ffs((long)mask); 1279 mask = sigmask(signum); 1280 1281 /* take the signal! */ 1282 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1283 ps_siglist & ~mask) != ps_siglist) { 1284 /* lost race taking the process signal, restart */ 1285 continue; 1286 } 1287 atomic_clearbits_int(&p->p_siglist, mask); 1288 setsigctx(p, signum, sctx); 1289 1290 /* 1291 * We should see pending but ignored signals 1292 * only if PS_TRACED was on when they were posted. 1293 */ 1294 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1295 continue; 1296 1297 /* 1298 * If traced, always stop, and stay stopped until released 1299 * by the debugger. If our parent process is waiting for 1300 * us, don't hang as we could deadlock. 1301 */ 1302 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1303 signum != SIGKILL) { 1304 single_thread_set(p, SINGLE_SUSPEND, 0); 1305 pr->ps_xsig = signum; 1306 1307 if (dolock) 1308 SCHED_LOCK(s); 1309 proc_stop(p, 1); 1310 if (dolock) 1311 SCHED_UNLOCK(s); 1312 1313 /* 1314 * re-take the signal before releasing 1315 * the other threads. Must check the continue 1316 * conditions below and only take the signal if 1317 * those are not true. 1318 */ 1319 signum = pr->ps_xsig; 1320 mask = sigmask(signum); 1321 setsigctx(p, signum, sctx); 1322 if (!((pr->ps_flags & PS_TRACED) == 0 || 1323 signum == 0 || 1324 (p->p_sigmask & mask) != 0)) { 1325 atomic_clearbits_int(&p->p_siglist, mask); 1326 atomic_clearbits_int(&pr->ps_siglist, mask); 1327 } 1328 1329 single_thread_clear(p, 0); 1330 1331 /* 1332 * If we are no longer being traced, or the parent 1333 * didn't give us a signal, look for more signals. 1334 */ 1335 if ((pr->ps_flags & PS_TRACED) == 0 || 1336 signum == 0) 1337 continue; 1338 1339 /* 1340 * If the new signal is being masked, look for other 1341 * signals. 1342 */ 1343 if ((p->p_sigmask & mask) != 0) 1344 continue; 1345 1346 } 1347 1348 prop = sigprop[signum]; 1349 1350 /* 1351 * Decide whether the signal should be returned. 1352 * Return the signal's number, or fall through 1353 * to clear it from the pending mask. 1354 */ 1355 switch ((long)sctx->sig_action) { 1356 case (long)SIG_DFL: 1357 /* 1358 * Don't take default actions on system processes. 1359 */ 1360 if (pr->ps_pid <= 1) { 1361 #ifdef DIAGNOSTIC 1362 /* 1363 * Are you sure you want to ignore SIGSEGV 1364 * in init? XXX 1365 */ 1366 printf("Process (pid %d) got signal" 1367 " %d\n", pr->ps_pid, signum); 1368 #endif 1369 break; /* == ignore */ 1370 } 1371 /* 1372 * If there is a pending stop signal to process 1373 * with default action, stop here, 1374 * then clear the signal. However, 1375 * if process is member of an orphaned 1376 * process group, ignore tty stop signals. 1377 */ 1378 if (prop & SA_STOP) { 1379 if (pr->ps_flags & PS_TRACED || 1380 (pr->ps_pgrp->pg_jobc == 0 && 1381 prop & SA_TTYSTOP)) 1382 break; /* == ignore */ 1383 pr->ps_xsig = signum; 1384 if (dolock) 1385 SCHED_LOCK(s); 1386 proc_stop(p, 1); 1387 if (dolock) 1388 SCHED_UNLOCK(s); 1389 break; 1390 } else if (prop & SA_IGNORE) { 1391 /* 1392 * Except for SIGCONT, shouldn't get here. 1393 * Default action is to ignore; drop it. 1394 */ 1395 break; /* == ignore */ 1396 } else 1397 goto keep; 1398 /* NOTREACHED */ 1399 case (long)SIG_IGN: 1400 /* 1401 * Masking above should prevent us ever trying 1402 * to take action on an ignored signal other 1403 * than SIGCONT, unless process is traced. 1404 */ 1405 if ((prop & SA_CONT) == 0 && 1406 (pr->ps_flags & PS_TRACED) == 0) 1407 printf("%s\n", __func__); 1408 break; /* == ignore */ 1409 default: 1410 /* 1411 * This signal has an action, let 1412 * postsig() process it. 1413 */ 1414 goto keep; 1415 } 1416 } 1417 /* NOTREACHED */ 1418 1419 keep: 1420 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1421 return (signum); 1422 } 1423 1424 /* 1425 * Put the argument process into the stopped state and notify the parent 1426 * via wakeup. Signals are handled elsewhere. The process must not be 1427 * on the run queue. 1428 */ 1429 void 1430 proc_stop(struct proc *p, int sw) 1431 { 1432 struct process *pr = p->p_p; 1433 1434 #ifdef MULTIPROCESSOR 1435 SCHED_ASSERT_LOCKED(); 1436 #endif 1437 1438 p->p_stat = SSTOP; 1439 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1440 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1441 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1442 /* 1443 * We need this soft interrupt to be handled fast. 1444 * Extra calls to softclock don't hurt. 1445 */ 1446 softintr_schedule(proc_stop_si); 1447 if (sw) 1448 mi_switch(); 1449 } 1450 1451 /* 1452 * Called from a soft interrupt to send signals to the parents of stopped 1453 * processes. 1454 * We can't do this in proc_stop because it's called with nasty locks held 1455 * and we would need recursive scheduler lock to deal with that. 1456 */ 1457 void 1458 proc_stop_sweep(void *v) 1459 { 1460 struct process *pr; 1461 1462 LIST_FOREACH(pr, &allprocess, ps_list) { 1463 if ((pr->ps_flags & PS_STOPPED) == 0) 1464 continue; 1465 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1466 1467 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1468 prsignal(pr->ps_pptr, SIGCHLD); 1469 wakeup(pr->ps_pptr); 1470 } 1471 } 1472 1473 /* 1474 * Take the action for the specified signal 1475 * from the current set of pending signals. 1476 */ 1477 void 1478 postsig(struct proc *p, int signum, struct sigctx *sctx) 1479 { 1480 u_long trapno; 1481 int mask, returnmask; 1482 siginfo_t si; 1483 union sigval sigval; 1484 int code; 1485 1486 KASSERT(signum != 0); 1487 1488 mask = sigmask(signum); 1489 atomic_clearbits_int(&p->p_siglist, mask); 1490 sigval.sival_ptr = NULL; 1491 1492 if (p->p_sisig != signum) { 1493 trapno = 0; 1494 code = SI_USER; 1495 sigval.sival_ptr = NULL; 1496 } else { 1497 trapno = p->p_sitrapno; 1498 code = p->p_sicode; 1499 sigval = p->p_sigval; 1500 } 1501 initsiginfo(&si, signum, trapno, code, sigval); 1502 1503 #ifdef KTRACE 1504 if (KTRPOINT(p, KTR_PSIG)) { 1505 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1506 p->p_oldmask : p->p_sigmask, code, &si); 1507 } 1508 #endif 1509 if (sctx->sig_action == SIG_DFL) { 1510 /* 1511 * Default action, where the default is to kill 1512 * the process. (Other cases were ignored above.) 1513 */ 1514 KERNEL_LOCK(); 1515 sigexit(p, signum); 1516 /* NOTREACHED */ 1517 } else { 1518 /* 1519 * If we get here, the signal must be caught. 1520 */ 1521 #ifdef DIAGNOSTIC 1522 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1523 panic("postsig action"); 1524 #endif 1525 /* 1526 * Set the new mask value and also defer further 1527 * occurrences of this signal. 1528 * 1529 * Special case: user has done a sigpause. Here the 1530 * current mask is not of interest, but rather the 1531 * mask from before the sigpause is what we want 1532 * restored after the signal processing is completed. 1533 */ 1534 if (p->p_flag & P_SIGSUSPEND) { 1535 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1536 returnmask = p->p_oldmask; 1537 } else { 1538 returnmask = p->p_sigmask; 1539 } 1540 if (p->p_sisig == signum) { 1541 p->p_sisig = 0; 1542 p->p_sitrapno = 0; 1543 p->p_sicode = SI_USER; 1544 p->p_sigval.sival_ptr = NULL; 1545 } 1546 1547 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1548 sctx->sig_info, sctx->sig_onstack)) { 1549 KERNEL_LOCK(); 1550 sigexit(p, SIGILL); 1551 /* NOTREACHED */ 1552 } 1553 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1554 } 1555 } 1556 1557 /* 1558 * Force the current process to exit with the specified signal, dumping core 1559 * if appropriate. We bypass the normal tests for masked and caught signals, 1560 * allowing unrecoverable failures to terminate the process without changing 1561 * signal state. Mark the accounting record with the signal termination. 1562 * If dumping core, save the signal number for the debugger. Calls exit and 1563 * does not return. 1564 */ 1565 void 1566 sigexit(struct proc *p, int signum) 1567 { 1568 /* Mark process as going away */ 1569 atomic_setbits_int(&p->p_flag, P_WEXIT); 1570 1571 p->p_p->ps_acflag |= AXSIG; 1572 if (sigprop[signum] & SA_CORE) { 1573 p->p_sisig = signum; 1574 1575 /* if there are other threads, pause them */ 1576 if (P_HASSIBLING(p)) 1577 single_thread_set(p, SINGLE_SUSPEND, 1); 1578 1579 if (coredump(p) == 0) 1580 signum |= WCOREFLAG; 1581 } 1582 exit1(p, 0, signum, EXIT_NORMAL); 1583 /* NOTREACHED */ 1584 } 1585 1586 /* 1587 * Send uncatchable SIGABRT for coredump. 1588 */ 1589 void 1590 sigabort(struct proc *p) 1591 { 1592 struct sigaction sa; 1593 1594 memset(&sa, 0, sizeof sa); 1595 sa.sa_handler = SIG_DFL; 1596 setsigvec(p, SIGABRT, &sa); 1597 atomic_clearbits_int(&p->p_sigmask, sigmask(SIGABRT)); 1598 psignal(p, SIGABRT); 1599 } 1600 1601 /* 1602 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1603 * thread, and 0 otherwise. 1604 */ 1605 int 1606 sigismasked(struct proc *p, int sig) 1607 { 1608 struct process *pr = p->p_p; 1609 int rv; 1610 1611 mtx_enter(&pr->ps_mtx); 1612 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1613 (p->p_sigmask & sigmask(sig)); 1614 mtx_leave(&pr->ps_mtx); 1615 1616 return !!rv; 1617 } 1618 1619 struct coredump_iostate { 1620 struct proc *io_proc; 1621 struct vnode *io_vp; 1622 struct ucred *io_cred; 1623 off_t io_offset; 1624 }; 1625 1626 /* 1627 * Dump core, into a file named "progname.core", unless the process was 1628 * setuid/setgid. 1629 */ 1630 int 1631 coredump(struct proc *p) 1632 { 1633 #ifdef SMALL_KERNEL 1634 return EPERM; 1635 #else 1636 struct process *pr = p->p_p; 1637 struct vnode *vp; 1638 struct ucred *cred = p->p_ucred; 1639 struct vmspace *vm = p->p_vmspace; 1640 struct nameidata nd; 1641 struct vattr vattr; 1642 struct coredump_iostate io; 1643 int error, len, incrash = 0; 1644 char *name; 1645 const char *dir = "/var/crash"; 1646 1647 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1648 1649 /* Don't dump if will exceed file size limit. */ 1650 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1651 return (EFBIG); 1652 1653 name = pool_get(&namei_pool, PR_WAITOK); 1654 1655 /* 1656 * If the process has inconsistent uids, nosuidcoredump 1657 * determines coredump placement policy. 1658 */ 1659 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1660 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1661 if (nosuidcoredump == 3) { 1662 /* 1663 * If the program directory does not exist, dumps of 1664 * that core will silently fail. 1665 */ 1666 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1667 dir, pr->ps_comm, pr->ps_pid); 1668 incrash = KERNELPATH; 1669 } else if (nosuidcoredump == 2) { 1670 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1671 dir, pr->ps_comm); 1672 incrash = KERNELPATH; 1673 } else { 1674 pool_put(&namei_pool, name); 1675 return (EPERM); 1676 } 1677 } else 1678 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1679 1680 if (len >= MAXPATHLEN) { 1681 pool_put(&namei_pool, name); 1682 return (EACCES); 1683 } 1684 1685 /* 1686 * Control the UID used to write out. The normal case uses 1687 * the real UID. If the sugid case is going to write into the 1688 * controlled directory, we do so as root. 1689 */ 1690 if (incrash == 0) { 1691 cred = crdup(cred); 1692 cred->cr_uid = cred->cr_ruid; 1693 cred->cr_gid = cred->cr_rgid; 1694 } else { 1695 if (p->p_fd->fd_rdir) { 1696 vrele(p->p_fd->fd_rdir); 1697 p->p_fd->fd_rdir = NULL; 1698 } 1699 p->p_ucred = crdup(p->p_ucred); 1700 crfree(cred); 1701 cred = p->p_ucred; 1702 crhold(cred); 1703 cred->cr_uid = 0; 1704 cred->cr_gid = 0; 1705 } 1706 1707 /* incrash should be 0 or KERNELPATH only */ 1708 NDINIT(&nd, 0, incrash, UIO_SYSSPACE, name, p); 1709 1710 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1711 S_IRUSR | S_IWUSR); 1712 1713 if (error) 1714 goto out; 1715 1716 /* 1717 * Don't dump to non-regular files, files with links, or files 1718 * owned by someone else. 1719 */ 1720 vp = nd.ni_vp; 1721 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1722 VOP_UNLOCK(vp); 1723 vn_close(vp, FWRITE, cred, p); 1724 goto out; 1725 } 1726 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1727 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1728 vattr.va_uid != cred->cr_uid) { 1729 error = EACCES; 1730 VOP_UNLOCK(vp); 1731 vn_close(vp, FWRITE, cred, p); 1732 goto out; 1733 } 1734 VATTR_NULL(&vattr); 1735 vattr.va_size = 0; 1736 VOP_SETATTR(vp, &vattr, cred, p); 1737 pr->ps_acflag |= ACORE; 1738 1739 io.io_proc = p; 1740 io.io_vp = vp; 1741 io.io_cred = cred; 1742 io.io_offset = 0; 1743 VOP_UNLOCK(vp); 1744 vref(vp); 1745 error = vn_close(vp, FWRITE, cred, p); 1746 if (error == 0) 1747 error = coredump_elf(p, &io); 1748 vrele(vp); 1749 out: 1750 crfree(cred); 1751 pool_put(&namei_pool, name); 1752 return (error); 1753 #endif 1754 } 1755 1756 #ifndef SMALL_KERNEL 1757 int 1758 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1759 { 1760 struct coredump_iostate *io = cookie; 1761 off_t coffset = 0; 1762 size_t csize; 1763 int chunk, error; 1764 1765 csize = len; 1766 do { 1767 if (sigmask(SIGKILL) & 1768 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1769 return (EINTR); 1770 1771 /* Rest of the loop sleeps with lock held, so... */ 1772 yield(); 1773 1774 chunk = MIN(csize, MAXPHYS); 1775 error = vn_rdwr(UIO_WRITE, io->io_vp, 1776 (caddr_t)data + coffset, chunk, 1777 io->io_offset + coffset, segflg, 1778 IO_UNIT, io->io_cred, NULL, io->io_proc); 1779 if (error) { 1780 struct process *pr = io->io_proc->p_p; 1781 1782 if (error == ENOSPC) 1783 log(LOG_ERR, 1784 "coredump of %s(%d) failed, filesystem full\n", 1785 pr->ps_comm, pr->ps_pid); 1786 else 1787 log(LOG_ERR, 1788 "coredump of %s(%d), write failed: errno %d\n", 1789 pr->ps_comm, pr->ps_pid, error); 1790 return (error); 1791 } 1792 1793 coffset += chunk; 1794 csize -= chunk; 1795 } while (csize > 0); 1796 1797 io->io_offset += len; 1798 return (0); 1799 } 1800 1801 void 1802 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1803 { 1804 struct coredump_iostate *io = cookie; 1805 1806 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1807 } 1808 1809 #endif /* !SMALL_KERNEL */ 1810 1811 /* 1812 * Nonexistent system call-- signal process (may want to handle it). 1813 * Flag error in case process won't see signal immediately (blocked or ignored). 1814 */ 1815 int 1816 sys_nosys(struct proc *p, void *v, register_t *retval) 1817 { 1818 ptsignal(p, SIGSYS, STHREAD); 1819 return (ENOSYS); 1820 } 1821 1822 int 1823 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1824 { 1825 static int sigwaitsleep; 1826 struct sys___thrsigdivert_args /* { 1827 syscallarg(sigset_t) sigmask; 1828 syscallarg(siginfo_t *) info; 1829 syscallarg(const struct timespec *) timeout; 1830 } */ *uap = v; 1831 struct sigctx ctx; 1832 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1833 siginfo_t si; 1834 uint64_t nsecs = INFSLP; 1835 int timeinvalid = 0; 1836 int error = 0; 1837 1838 memset(&si, 0, sizeof(si)); 1839 1840 if (SCARG(uap, timeout) != NULL) { 1841 struct timespec ts; 1842 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1843 return (error); 1844 #ifdef KTRACE 1845 if (KTRPOINT(p, KTR_STRUCT)) 1846 ktrreltimespec(p, &ts); 1847 #endif 1848 if (!timespecisvalid(&ts)) 1849 timeinvalid = 1; 1850 else 1851 nsecs = TIMESPEC_TO_NSEC(&ts); 1852 } 1853 1854 dosigsuspend(p, p->p_sigmask &~ mask); 1855 for (;;) { 1856 si.si_signo = cursig(p, &ctx); 1857 if (si.si_signo != 0) { 1858 sigset_t smask = sigmask(si.si_signo); 1859 if (smask & mask) { 1860 atomic_clearbits_int(&p->p_siglist, smask); 1861 error = 0; 1862 break; 1863 } 1864 } 1865 1866 /* per-POSIX, delay this error until after the above */ 1867 if (timeinvalid) 1868 error = EINVAL; 1869 /* per-POSIX, return immediately if timeout is zero-valued */ 1870 if (nsecs == 0) 1871 error = EAGAIN; 1872 1873 if (error != 0) 1874 break; 1875 1876 error = tsleep_nsec(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1877 nsecs); 1878 } 1879 1880 if (error == 0) { 1881 *retval = si.si_signo; 1882 if (SCARG(uap, info) != NULL) 1883 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1884 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1885 /* 1886 * Restarting is wrong if there's a timeout, as it'll be 1887 * for the same interval again 1888 */ 1889 error = EINTR; 1890 } 1891 1892 return (error); 1893 } 1894 1895 void 1896 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1897 { 1898 memset(si, 0, sizeof(*si)); 1899 1900 si->si_signo = sig; 1901 si->si_code = code; 1902 if (code == SI_USER) { 1903 si->si_value = val; 1904 } else { 1905 switch (sig) { 1906 case SIGSEGV: 1907 case SIGILL: 1908 case SIGBUS: 1909 case SIGFPE: 1910 si->si_addr = val.sival_ptr; 1911 si->si_trapno = trapno; 1912 break; 1913 case SIGXFSZ: 1914 break; 1915 } 1916 } 1917 } 1918 1919 int 1920 filt_sigattach(struct knote *kn) 1921 { 1922 struct process *pr = curproc->p_p; 1923 int s; 1924 1925 if (kn->kn_id >= NSIG) 1926 return EINVAL; 1927 1928 kn->kn_ptr.p_process = pr; 1929 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1930 1931 s = splhigh(); 1932 klist_insert_locked(&pr->ps_klist, kn); 1933 splx(s); 1934 1935 return (0); 1936 } 1937 1938 void 1939 filt_sigdetach(struct knote *kn) 1940 { 1941 struct process *pr = kn->kn_ptr.p_process; 1942 int s; 1943 1944 s = splhigh(); 1945 klist_remove_locked(&pr->ps_klist, kn); 1946 splx(s); 1947 } 1948 1949 /* 1950 * signal knotes are shared with proc knotes, so we apply a mask to 1951 * the hint in order to differentiate them from process hints. This 1952 * could be avoided by using a signal-specific knote list, but probably 1953 * isn't worth the trouble. 1954 */ 1955 int 1956 filt_signal(struct knote *kn, long hint) 1957 { 1958 1959 if (hint & NOTE_SIGNAL) { 1960 hint &= ~NOTE_SIGNAL; 1961 1962 if (kn->kn_id == hint) 1963 kn->kn_data++; 1964 } 1965 return (kn->kn_data != 0); 1966 } 1967 1968 void 1969 userret(struct proc *p) 1970 { 1971 struct sigctx ctx; 1972 int signum; 1973 1974 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1975 if (p->p_flag & P_PROFPEND) { 1976 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1977 KERNEL_LOCK(); 1978 psignal(p, SIGPROF); 1979 KERNEL_UNLOCK(); 1980 } 1981 if (p->p_flag & P_ALRMPEND) { 1982 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1983 KERNEL_LOCK(); 1984 psignal(p, SIGVTALRM); 1985 KERNEL_UNLOCK(); 1986 } 1987 1988 if (SIGPENDING(p) != 0) { 1989 while ((signum = cursig(p, &ctx)) != 0) 1990 postsig(p, signum, &ctx); 1991 } 1992 1993 /* 1994 * If P_SIGSUSPEND is still set here, then we still need to restore 1995 * the original sigmask before returning to userspace. Also, this 1996 * might unmask some pending signals, so we need to check a second 1997 * time for signals to post. 1998 */ 1999 if (p->p_flag & P_SIGSUSPEND) { 2000 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2001 p->p_sigmask = p->p_oldmask; 2002 2003 while ((signum = cursig(p, &ctx)) != 0) 2004 postsig(p, signum, &ctx); 2005 } 2006 2007 if (p->p_flag & P_SUSPSINGLE) 2008 single_thread_check(p, 0); 2009 2010 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2011 2012 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2013 } 2014 2015 int 2016 single_thread_check_locked(struct proc *p, int deep, int s) 2017 { 2018 struct process *pr = p->p_p; 2019 2020 SCHED_ASSERT_LOCKED(); 2021 2022 if (pr->ps_single != NULL && pr->ps_single != p) { 2023 do { 2024 /* if we're in deep, we need to unwind to the edge */ 2025 if (deep) { 2026 if (pr->ps_flags & PS_SINGLEUNWIND) 2027 return (ERESTART); 2028 if (pr->ps_flags & PS_SINGLEEXIT) 2029 return (EINTR); 2030 } 2031 2032 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 2033 wakeup(&pr->ps_singlecount); 2034 2035 if (pr->ps_flags & PS_SINGLEEXIT) { 2036 SCHED_UNLOCK(s); 2037 KERNEL_LOCK(); 2038 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2039 /* NOTREACHED */ 2040 } 2041 2042 /* not exiting and don't need to unwind, so suspend */ 2043 p->p_stat = SSTOP; 2044 mi_switch(); 2045 } while (pr->ps_single != NULL); 2046 } 2047 2048 return (0); 2049 } 2050 2051 int 2052 single_thread_check(struct proc *p, int deep) 2053 { 2054 int s, error; 2055 2056 SCHED_LOCK(s); 2057 error = single_thread_check_locked(p, deep, s); 2058 SCHED_UNLOCK(s); 2059 2060 return error; 2061 } 2062 2063 /* 2064 * Stop other threads in the process. The mode controls how and 2065 * where the other threads should stop: 2066 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 2067 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 2068 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2069 * or released as with SINGLE_SUSPEND 2070 * - SINGLE_EXIT: unwind to kernel boundary and exit 2071 */ 2072 int 2073 single_thread_set(struct proc *p, enum single_thread_mode mode, int wait) 2074 { 2075 struct process *pr = p->p_p; 2076 struct proc *q; 2077 int error, s; 2078 2079 KASSERT(curproc == p); 2080 2081 SCHED_LOCK(s); 2082 error = single_thread_check_locked(p, (mode == SINGLE_UNWIND), s); 2083 if (error) { 2084 SCHED_UNLOCK(s); 2085 return error; 2086 } 2087 2088 switch (mode) { 2089 case SINGLE_SUSPEND: 2090 break; 2091 case SINGLE_UNWIND: 2092 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2093 break; 2094 case SINGLE_EXIT: 2095 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2096 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2097 break; 2098 #ifdef DIAGNOSTIC 2099 default: 2100 panic("single_thread_mode = %d", mode); 2101 #endif 2102 } 2103 pr->ps_singlecount = 0; 2104 membar_producer(); 2105 pr->ps_single = p; 2106 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2107 if (q == p) 2108 continue; 2109 if (q->p_flag & P_WEXIT) { 2110 if (mode == SINGLE_EXIT) { 2111 if (q->p_stat == SSTOP) { 2112 setrunnable(q); 2113 atomic_inc_int(&pr->ps_singlecount); 2114 } 2115 } 2116 continue; 2117 } 2118 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2119 switch (q->p_stat) { 2120 case SIDL: 2121 case SRUN: 2122 atomic_inc_int(&pr->ps_singlecount); 2123 break; 2124 case SSLEEP: 2125 /* if it's not interruptible, then just have to wait */ 2126 if (q->p_flag & P_SINTR) { 2127 /* merely need to suspend? just stop it */ 2128 if (mode == SINGLE_SUSPEND) { 2129 q->p_stat = SSTOP; 2130 break; 2131 } 2132 /* need to unwind or exit, so wake it */ 2133 setrunnable(q); 2134 } 2135 atomic_inc_int(&pr->ps_singlecount); 2136 break; 2137 case SSTOP: 2138 if (mode == SINGLE_EXIT) { 2139 setrunnable(q); 2140 atomic_inc_int(&pr->ps_singlecount); 2141 } 2142 break; 2143 case SDEAD: 2144 break; 2145 case SONPROC: 2146 atomic_inc_int(&pr->ps_singlecount); 2147 signotify(q); 2148 break; 2149 } 2150 } 2151 SCHED_UNLOCK(s); 2152 2153 if (wait) 2154 single_thread_wait(pr, 1); 2155 2156 return 0; 2157 } 2158 2159 /* 2160 * Wait for other threads to stop. If recheck is false then the function 2161 * returns non-zero if the caller needs to restart the check else 0 is 2162 * returned. If recheck is true the return value is always 0. 2163 */ 2164 int 2165 single_thread_wait(struct process *pr, int recheck) 2166 { 2167 struct sleep_state sls; 2168 int wait; 2169 2170 /* wait until they're all suspended */ 2171 wait = pr->ps_singlecount > 0; 2172 while (wait) { 2173 sleep_setup(&sls, &pr->ps_singlecount, PWAIT, "suspend", 0); 2174 wait = pr->ps_singlecount > 0; 2175 sleep_finish(&sls, wait); 2176 if (!recheck) 2177 break; 2178 } 2179 2180 return wait; 2181 } 2182 2183 void 2184 single_thread_clear(struct proc *p, int flag) 2185 { 2186 struct process *pr = p->p_p; 2187 struct proc *q; 2188 int s; 2189 2190 KASSERT(pr->ps_single == p); 2191 KASSERT(curproc == p); 2192 2193 SCHED_LOCK(s); 2194 pr->ps_single = NULL; 2195 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2196 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2197 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2198 continue; 2199 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2200 2201 /* 2202 * if the thread was only stopped for single threading 2203 * then clearing that either makes it runnable or puts 2204 * it back into some sleep queue 2205 */ 2206 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2207 if (q->p_wchan == NULL) 2208 setrunnable(q); 2209 else 2210 q->p_stat = SSLEEP; 2211 } 2212 } 2213 SCHED_UNLOCK(s); 2214 } 2215 2216 void 2217 sigio_del(struct sigiolst *rmlist) 2218 { 2219 struct sigio *sigio; 2220 2221 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2222 LIST_REMOVE(sigio, sio_pgsigio); 2223 crfree(sigio->sio_ucred); 2224 free(sigio, M_SIGIO, sizeof(*sigio)); 2225 } 2226 } 2227 2228 void 2229 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2230 { 2231 struct sigio *sigio; 2232 2233 MUTEX_ASSERT_LOCKED(&sigio_lock); 2234 2235 sigio = sir->sir_sigio; 2236 if (sigio != NULL) { 2237 KASSERT(sigio->sio_myref == sir); 2238 sir->sir_sigio = NULL; 2239 2240 if (sigio->sio_pgid > 0) 2241 sigio->sio_proc = NULL; 2242 else 2243 sigio->sio_pgrp = NULL; 2244 LIST_REMOVE(sigio, sio_pgsigio); 2245 2246 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2247 } 2248 } 2249 2250 void 2251 sigio_free(struct sigio_ref *sir) 2252 { 2253 struct sigiolst rmlist; 2254 2255 if (sir->sir_sigio == NULL) 2256 return; 2257 2258 LIST_INIT(&rmlist); 2259 2260 mtx_enter(&sigio_lock); 2261 sigio_unlink(sir, &rmlist); 2262 mtx_leave(&sigio_lock); 2263 2264 sigio_del(&rmlist); 2265 } 2266 2267 void 2268 sigio_freelist(struct sigiolst *sigiolst) 2269 { 2270 struct sigiolst rmlist; 2271 struct sigio *sigio; 2272 2273 if (LIST_EMPTY(sigiolst)) 2274 return; 2275 2276 LIST_INIT(&rmlist); 2277 2278 mtx_enter(&sigio_lock); 2279 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2280 sigio_unlink(sigio->sio_myref, &rmlist); 2281 mtx_leave(&sigio_lock); 2282 2283 sigio_del(&rmlist); 2284 } 2285 2286 int 2287 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2288 { 2289 struct sigiolst rmlist; 2290 struct proc *p = curproc; 2291 struct pgrp *pgrp = NULL; 2292 struct process *pr = NULL; 2293 struct sigio *sigio; 2294 int error; 2295 pid_t pgid = *(int *)data; 2296 2297 if (pgid == 0) { 2298 sigio_free(sir); 2299 return (0); 2300 } 2301 2302 if (cmd == TIOCSPGRP) { 2303 if (pgid < 0) 2304 return (EINVAL); 2305 pgid = -pgid; 2306 } 2307 2308 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2309 sigio->sio_pgid = pgid; 2310 sigio->sio_ucred = crhold(p->p_ucred); 2311 sigio->sio_myref = sir; 2312 2313 LIST_INIT(&rmlist); 2314 2315 /* 2316 * The kernel lock, and not sleeping between prfind()/pgfind() and 2317 * linking of the sigio ensure that the process or process group does 2318 * not disappear unexpectedly. 2319 */ 2320 KERNEL_LOCK(); 2321 mtx_enter(&sigio_lock); 2322 2323 if (pgid > 0) { 2324 pr = prfind(pgid); 2325 if (pr == NULL) { 2326 error = ESRCH; 2327 goto fail; 2328 } 2329 2330 /* 2331 * Policy - Don't allow a process to FSETOWN a process 2332 * in another session. 2333 * 2334 * Remove this test to allow maximum flexibility or 2335 * restrict FSETOWN to the current process or process 2336 * group for maximum safety. 2337 */ 2338 if (pr->ps_session != p->p_p->ps_session) { 2339 error = EPERM; 2340 goto fail; 2341 } 2342 2343 if ((pr->ps_flags & PS_EXITING) != 0) { 2344 error = ESRCH; 2345 goto fail; 2346 } 2347 } else /* if (pgid < 0) */ { 2348 pgrp = pgfind(-pgid); 2349 if (pgrp == NULL) { 2350 error = ESRCH; 2351 goto fail; 2352 } 2353 2354 /* 2355 * Policy - Don't allow a process to FSETOWN a process 2356 * in another session. 2357 * 2358 * Remove this test to allow maximum flexibility or 2359 * restrict FSETOWN to the current process or process 2360 * group for maximum safety. 2361 */ 2362 if (pgrp->pg_session != p->p_p->ps_session) { 2363 error = EPERM; 2364 goto fail; 2365 } 2366 } 2367 2368 if (pgid > 0) { 2369 sigio->sio_proc = pr; 2370 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2371 } else { 2372 sigio->sio_pgrp = pgrp; 2373 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2374 } 2375 2376 sigio_unlink(sir, &rmlist); 2377 sir->sir_sigio = sigio; 2378 2379 mtx_leave(&sigio_lock); 2380 KERNEL_UNLOCK(); 2381 2382 sigio_del(&rmlist); 2383 2384 return (0); 2385 2386 fail: 2387 mtx_leave(&sigio_lock); 2388 KERNEL_UNLOCK(); 2389 2390 crfree(sigio->sio_ucred); 2391 free(sigio, M_SIGIO, sizeof(*sigio)); 2392 2393 return (error); 2394 } 2395 2396 void 2397 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2398 { 2399 struct sigio *sigio; 2400 pid_t pgid = 0; 2401 2402 mtx_enter(&sigio_lock); 2403 sigio = sir->sir_sigio; 2404 if (sigio != NULL) 2405 pgid = sigio->sio_pgid; 2406 mtx_leave(&sigio_lock); 2407 2408 if (cmd == TIOCGPGRP) 2409 pgid = -pgid; 2410 2411 *(int *)data = pgid; 2412 } 2413 2414 void 2415 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2416 { 2417 struct sigiolst rmlist; 2418 struct sigio *newsigio, *sigio; 2419 2420 sigio_free(dst); 2421 2422 if (src->sir_sigio == NULL) 2423 return; 2424 2425 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2426 LIST_INIT(&rmlist); 2427 2428 mtx_enter(&sigio_lock); 2429 2430 sigio = src->sir_sigio; 2431 if (sigio == NULL) { 2432 mtx_leave(&sigio_lock); 2433 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2434 return; 2435 } 2436 2437 newsigio->sio_pgid = sigio->sio_pgid; 2438 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2439 newsigio->sio_myref = dst; 2440 if (newsigio->sio_pgid > 0) { 2441 newsigio->sio_proc = sigio->sio_proc; 2442 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2443 sio_pgsigio); 2444 } else { 2445 newsigio->sio_pgrp = sigio->sio_pgrp; 2446 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2447 sio_pgsigio); 2448 } 2449 2450 sigio_unlink(dst, &rmlist); 2451 dst->sir_sigio = newsigio; 2452 2453 mtx_leave(&sigio_lock); 2454 2455 sigio_del(&rmlist); 2456 } 2457