1 /* $OpenBSD: kern_sig.c,v 1.258 2020/06/15 13:18:33 visa 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 68 #include <sys/mount.h> 69 #include <sys/syscallargs.h> 70 71 #include <uvm/uvm_extern.h> 72 #include <machine/tcb.h> 73 74 int filt_sigattach(struct knote *kn); 75 void filt_sigdetach(struct knote *kn); 76 int filt_signal(struct knote *kn, long hint); 77 78 const struct filterops sig_filtops = { 79 .f_flags = 0, 80 .f_attach = filt_sigattach, 81 .f_detach = filt_sigdetach, 82 .f_event = filt_signal, 83 }; 84 85 const int sigprop[NSIG + 1] = { 86 0, /* unused */ 87 SA_KILL, /* SIGHUP */ 88 SA_KILL, /* SIGINT */ 89 SA_KILL|SA_CORE, /* SIGQUIT */ 90 SA_KILL|SA_CORE, /* SIGILL */ 91 SA_KILL|SA_CORE, /* SIGTRAP */ 92 SA_KILL|SA_CORE, /* SIGABRT */ 93 SA_KILL|SA_CORE, /* SIGEMT */ 94 SA_KILL|SA_CORE, /* SIGFPE */ 95 SA_KILL, /* SIGKILL */ 96 SA_KILL|SA_CORE, /* SIGBUS */ 97 SA_KILL|SA_CORE, /* SIGSEGV */ 98 SA_KILL|SA_CORE, /* SIGSYS */ 99 SA_KILL, /* SIGPIPE */ 100 SA_KILL, /* SIGALRM */ 101 SA_KILL, /* SIGTERM */ 102 SA_IGNORE, /* SIGURG */ 103 SA_STOP, /* SIGSTOP */ 104 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 105 SA_IGNORE|SA_CONT, /* SIGCONT */ 106 SA_IGNORE, /* SIGCHLD */ 107 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 108 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 109 SA_IGNORE, /* SIGIO */ 110 SA_KILL, /* SIGXCPU */ 111 SA_KILL, /* SIGXFSZ */ 112 SA_KILL, /* SIGVTALRM */ 113 SA_KILL, /* SIGPROF */ 114 SA_IGNORE, /* SIGWINCH */ 115 SA_IGNORE, /* SIGINFO */ 116 SA_KILL, /* SIGUSR1 */ 117 SA_KILL, /* SIGUSR2 */ 118 SA_IGNORE, /* SIGTHR */ 119 }; 120 121 #define contsigmask (sigmask(SIGCONT)) 122 #define stopsigmask (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 123 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 124 125 void proc_stop(struct proc *p, int); 126 void proc_stop_sweep(void *); 127 void *proc_stop_si; 128 129 void postsig(struct proc *, int); 130 int cansignal(struct proc *, struct process *, int); 131 132 struct pool sigacts_pool; /* memory pool for sigacts structures */ 133 134 void sigio_del(struct sigiolst *); 135 void sigio_unlink(struct sigio_ref *, struct sigiolst *); 136 struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 137 138 /* 139 * Can thread p, send the signal signum to process qr? 140 */ 141 int 142 cansignal(struct proc *p, struct process *qr, int signum) 143 { 144 struct process *pr = p->p_p; 145 struct ucred *uc = p->p_ucred; 146 struct ucred *quc = qr->ps_ucred; 147 148 if (uc->cr_uid == 0) 149 return (1); /* root can always signal */ 150 151 if (pr == qr) 152 return (1); /* process can always signal itself */ 153 154 /* optimization: if the same creds then the tests below will pass */ 155 if (uc == quc) 156 return (1); 157 158 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 159 return (1); /* SIGCONT in session */ 160 161 /* 162 * Using kill(), only certain signals can be sent to setugid 163 * child processes 164 */ 165 if (qr->ps_flags & PS_SUGID) { 166 switch (signum) { 167 case 0: 168 case SIGKILL: 169 case SIGINT: 170 case SIGTERM: 171 case SIGALRM: 172 case SIGSTOP: 173 case SIGTTIN: 174 case SIGTTOU: 175 case SIGTSTP: 176 case SIGHUP: 177 case SIGUSR1: 178 case SIGUSR2: 179 if (uc->cr_ruid == quc->cr_ruid || 180 uc->cr_uid == quc->cr_ruid) 181 return (1); 182 } 183 return (0); 184 } 185 186 if (uc->cr_ruid == quc->cr_ruid || 187 uc->cr_ruid == quc->cr_svuid || 188 uc->cr_uid == quc->cr_ruid || 189 uc->cr_uid == quc->cr_svuid) 190 return (1); 191 return (0); 192 } 193 194 /* 195 * Initialize signal-related data structures. 196 */ 197 void 198 signal_init(void) 199 { 200 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 201 NULL); 202 if (proc_stop_si == NULL) 203 panic("signal_init failed to register softintr"); 204 205 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 206 PR_WAITOK, "sigapl", NULL); 207 } 208 209 /* 210 * Create an initial sigacts structure, using the same signal state 211 * as pr. 212 */ 213 struct sigacts * 214 sigactsinit(struct process *pr) 215 { 216 struct sigacts *ps; 217 218 ps = pool_get(&sigacts_pool, PR_WAITOK); 219 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 220 return (ps); 221 } 222 223 /* 224 * Initialize a new sigaltstack structure. 225 */ 226 void 227 sigstkinit(struct sigaltstack *ss) 228 { 229 ss->ss_flags = SS_DISABLE; 230 ss->ss_size = 0; 231 ss->ss_sp = 0; 232 } 233 234 /* 235 * Release a sigacts structure. 236 */ 237 void 238 sigactsfree(struct process *pr) 239 { 240 struct sigacts *ps = pr->ps_sigacts; 241 242 pr->ps_sigacts = NULL; 243 244 pool_put(&sigacts_pool, ps); 245 } 246 247 int 248 sys_sigaction(struct proc *p, void *v, register_t *retval) 249 { 250 struct sys_sigaction_args /* { 251 syscallarg(int) signum; 252 syscallarg(const struct sigaction *) nsa; 253 syscallarg(struct sigaction *) osa; 254 } */ *uap = v; 255 struct sigaction vec; 256 #ifdef KTRACE 257 struct sigaction ovec; 258 #endif 259 struct sigaction *sa; 260 const struct sigaction *nsa; 261 struct sigaction *osa; 262 struct sigacts *ps = p->p_p->ps_sigacts; 263 int signum; 264 int bit, error; 265 266 signum = SCARG(uap, signum); 267 nsa = SCARG(uap, nsa); 268 osa = SCARG(uap, osa); 269 270 if (signum <= 0 || signum >= NSIG || 271 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 272 return (EINVAL); 273 sa = &vec; 274 if (osa) { 275 sa->sa_handler = ps->ps_sigact[signum]; 276 sa->sa_mask = ps->ps_catchmask[signum]; 277 bit = sigmask(signum); 278 sa->sa_flags = 0; 279 if ((ps->ps_sigonstack & bit) != 0) 280 sa->sa_flags |= SA_ONSTACK; 281 if ((ps->ps_sigintr & bit) == 0) 282 sa->sa_flags |= SA_RESTART; 283 if ((ps->ps_sigreset & bit) != 0) 284 sa->sa_flags |= SA_RESETHAND; 285 if ((ps->ps_siginfo & bit) != 0) 286 sa->sa_flags |= SA_SIGINFO; 287 if (signum == SIGCHLD) { 288 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 289 sa->sa_flags |= SA_NOCLDSTOP; 290 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 291 sa->sa_flags |= SA_NOCLDWAIT; 292 } 293 if ((sa->sa_mask & bit) == 0) 294 sa->sa_flags |= SA_NODEFER; 295 sa->sa_mask &= ~bit; 296 error = copyout(sa, osa, sizeof (vec)); 297 if (error) 298 return (error); 299 #ifdef KTRACE 300 if (KTRPOINT(p, KTR_STRUCT)) 301 ovec = vec; 302 #endif 303 } 304 if (nsa) { 305 error = copyin(nsa, sa, sizeof (vec)); 306 if (error) 307 return (error); 308 #ifdef KTRACE 309 if (KTRPOINT(p, KTR_STRUCT)) 310 ktrsigaction(p, sa); 311 #endif 312 setsigvec(p, signum, sa); 313 } 314 #ifdef KTRACE 315 if (osa && KTRPOINT(p, KTR_STRUCT)) 316 ktrsigaction(p, &ovec); 317 #endif 318 return (0); 319 } 320 321 void 322 setsigvec(struct proc *p, int signum, struct sigaction *sa) 323 { 324 struct sigacts *ps = p->p_p->ps_sigacts; 325 int bit; 326 int s; 327 328 bit = sigmask(signum); 329 /* 330 * Change setting atomically. 331 */ 332 s = splhigh(); 333 ps->ps_sigact[signum] = sa->sa_handler; 334 if ((sa->sa_flags & SA_NODEFER) == 0) 335 sa->sa_mask |= sigmask(signum); 336 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 337 if (signum == SIGCHLD) { 338 if (sa->sa_flags & SA_NOCLDSTOP) 339 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 340 else 341 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 342 /* 343 * If the SA_NOCLDWAIT flag is set or the handler 344 * is SIG_IGN we reparent the dying child to PID 1 345 * (init) which will reap the zombie. Because we use 346 * init to do our dirty work we never set SAS_NOCLDWAIT 347 * for PID 1. 348 * XXX exit1 rework means this is unnecessary? 349 */ 350 if (initprocess->ps_sigacts != ps && 351 ((sa->sa_flags & SA_NOCLDWAIT) || 352 sa->sa_handler == SIG_IGN)) 353 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 354 else 355 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 356 } 357 if ((sa->sa_flags & SA_RESETHAND) != 0) 358 ps->ps_sigreset |= bit; 359 else 360 ps->ps_sigreset &= ~bit; 361 if ((sa->sa_flags & SA_SIGINFO) != 0) 362 ps->ps_siginfo |= bit; 363 else 364 ps->ps_siginfo &= ~bit; 365 if ((sa->sa_flags & SA_RESTART) == 0) 366 ps->ps_sigintr |= bit; 367 else 368 ps->ps_sigintr &= ~bit; 369 if ((sa->sa_flags & SA_ONSTACK) != 0) 370 ps->ps_sigonstack |= bit; 371 else 372 ps->ps_sigonstack &= ~bit; 373 /* 374 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 375 * and for signals set to SIG_DFL where the default is to ignore. 376 * However, don't put SIGCONT in ps_sigignore, 377 * as we have to restart the process. 378 */ 379 if (sa->sa_handler == SIG_IGN || 380 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 381 atomic_clearbits_int(&p->p_siglist, bit); 382 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 383 if (signum != SIGCONT) 384 ps->ps_sigignore |= bit; /* easier in psignal */ 385 ps->ps_sigcatch &= ~bit; 386 } else { 387 ps->ps_sigignore &= ~bit; 388 if (sa->sa_handler == SIG_DFL) 389 ps->ps_sigcatch &= ~bit; 390 else 391 ps->ps_sigcatch |= bit; 392 } 393 splx(s); 394 } 395 396 /* 397 * Initialize signal state for process 0; 398 * set to ignore signals that are ignored by default. 399 */ 400 void 401 siginit(struct process *pr) 402 { 403 struct sigacts *ps = pr->ps_sigacts; 404 int i; 405 406 for (i = 0; i < NSIG; i++) 407 if (sigprop[i] & SA_IGNORE && i != SIGCONT) 408 ps->ps_sigignore |= sigmask(i); 409 ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; 410 } 411 412 /* 413 * Reset signals for an exec by the specified thread. 414 */ 415 void 416 execsigs(struct proc *p) 417 { 418 struct sigacts *ps; 419 int nc, mask; 420 421 ps = p->p_p->ps_sigacts; 422 423 /* 424 * Reset caught signals. Held signals remain held 425 * through p_sigmask (unless they were caught, 426 * and are now ignored by default). 427 */ 428 while (ps->ps_sigcatch) { 429 nc = ffs((long)ps->ps_sigcatch); 430 mask = sigmask(nc); 431 ps->ps_sigcatch &= ~mask; 432 if (sigprop[nc] & SA_IGNORE) { 433 if (nc != SIGCONT) 434 ps->ps_sigignore |= mask; 435 atomic_clearbits_int(&p->p_siglist, mask); 436 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 437 } 438 ps->ps_sigact[nc] = SIG_DFL; 439 } 440 /* 441 * Reset stack state to the user stack. 442 * Clear set of signals caught on the signal stack. 443 */ 444 sigstkinit(&p->p_sigstk); 445 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 446 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 447 ps->ps_sigact[SIGCHLD] = SIG_DFL; 448 } 449 450 /* 451 * Manipulate signal mask. 452 * Note that we receive new mask, not pointer, 453 * and return old mask as return value; 454 * the library stub does the rest. 455 */ 456 int 457 sys_sigprocmask(struct proc *p, void *v, register_t *retval) 458 { 459 struct sys_sigprocmask_args /* { 460 syscallarg(int) how; 461 syscallarg(sigset_t) mask; 462 } */ *uap = v; 463 int error = 0; 464 sigset_t mask; 465 466 *retval = p->p_sigmask; 467 mask = SCARG(uap, mask) &~ sigcantmask; 468 469 switch (SCARG(uap, how)) { 470 case SIG_BLOCK: 471 atomic_setbits_int(&p->p_sigmask, mask); 472 break; 473 case SIG_UNBLOCK: 474 atomic_clearbits_int(&p->p_sigmask, mask); 475 break; 476 case SIG_SETMASK: 477 p->p_sigmask = mask; 478 break; 479 default: 480 error = EINVAL; 481 break; 482 } 483 return (error); 484 } 485 486 int 487 sys_sigpending(struct proc *p, void *v, register_t *retval) 488 { 489 490 *retval = p->p_siglist | p->p_p->ps_siglist; 491 return (0); 492 } 493 494 /* 495 * Temporarily replace calling proc's signal mask for the duration of a 496 * system call. Original signal mask will be restored by userret(). 497 */ 498 void 499 dosigsuspend(struct proc *p, sigset_t newmask) 500 { 501 KASSERT(p == curproc); 502 503 p->p_oldmask = p->p_sigmask; 504 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 505 p->p_sigmask = newmask; 506 } 507 508 /* 509 * Suspend process until signal, providing mask to be set 510 * in the meantime. Note nonstandard calling convention: 511 * libc stub passes mask, not pointer, to save a copyin. 512 */ 513 int 514 sys_sigsuspend(struct proc *p, void *v, register_t *retval) 515 { 516 struct sys_sigsuspend_args /* { 517 syscallarg(int) mask; 518 } */ *uap = v; 519 struct process *pr = p->p_p; 520 struct sigacts *ps = pr->ps_sigacts; 521 522 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 523 while (tsleep_nsec(ps, PPAUSE|PCATCH, "pause", INFSLP) == 0) 524 /* void */; 525 /* always return EINTR rather than ERESTART... */ 526 return (EINTR); 527 } 528 529 int 530 sigonstack(size_t stack) 531 { 532 const struct sigaltstack *ss = &curproc->p_sigstk; 533 534 return (ss->ss_flags & SS_DISABLE ? 0 : 535 (stack - (size_t)ss->ss_sp < ss->ss_size)); 536 } 537 538 int 539 sys_sigaltstack(struct proc *p, void *v, register_t *retval) 540 { 541 struct sys_sigaltstack_args /* { 542 syscallarg(const struct sigaltstack *) nss; 543 syscallarg(struct sigaltstack *) oss; 544 } */ *uap = v; 545 struct sigaltstack ss; 546 const struct sigaltstack *nss; 547 struct sigaltstack *oss; 548 int onstack = sigonstack(PROC_STACK(p)); 549 int error; 550 551 nss = SCARG(uap, nss); 552 oss = SCARG(uap, oss); 553 554 if (oss != NULL) { 555 ss = p->p_sigstk; 556 if (onstack) 557 ss.ss_flags |= SS_ONSTACK; 558 if ((error = copyout(&ss, oss, sizeof(ss)))) 559 return (error); 560 } 561 if (nss == NULL) 562 return (0); 563 error = copyin(nss, &ss, sizeof(ss)); 564 if (error) 565 return (error); 566 if (onstack) 567 return (EPERM); 568 if (ss.ss_flags & ~SS_DISABLE) 569 return (EINVAL); 570 if (ss.ss_flags & SS_DISABLE) { 571 p->p_sigstk.ss_flags = ss.ss_flags; 572 return (0); 573 } 574 if (ss.ss_size < MINSIGSTKSZ) 575 return (ENOMEM); 576 577 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 578 if (error) 579 return (error); 580 581 p->p_sigstk = ss; 582 return (0); 583 } 584 585 int 586 sys_kill(struct proc *cp, void *v, register_t *retval) 587 { 588 struct sys_kill_args /* { 589 syscallarg(int) pid; 590 syscallarg(int) signum; 591 } */ *uap = v; 592 struct process *pr; 593 int pid = SCARG(uap, pid); 594 int signum = SCARG(uap, signum); 595 int error; 596 int zombie = 0; 597 598 if ((error = pledge_kill(cp, pid)) != 0) 599 return (error); 600 if (((u_int)signum) >= NSIG) 601 return (EINVAL); 602 if (pid > 0) { 603 if ((pr = prfind(pid)) == NULL) { 604 if ((pr = zombiefind(pid)) == NULL) 605 return (ESRCH); 606 else 607 zombie = 1; 608 } 609 if (!cansignal(cp, pr, signum)) 610 return (EPERM); 611 612 /* kill single process */ 613 if (signum && !zombie) 614 prsignal(pr, signum); 615 return (0); 616 } 617 switch (pid) { 618 case -1: /* broadcast signal */ 619 return (killpg1(cp, signum, 0, 1)); 620 case 0: /* signal own process group */ 621 return (killpg1(cp, signum, 0, 0)); 622 default: /* negative explicit process group */ 623 return (killpg1(cp, signum, -pid, 0)); 624 } 625 } 626 627 int 628 sys_thrkill(struct proc *cp, void *v, register_t *retval) 629 { 630 struct sys_thrkill_args /* { 631 syscallarg(pid_t) tid; 632 syscallarg(int) signum; 633 syscallarg(void *) tcb; 634 } */ *uap = v; 635 struct proc *p; 636 int tid = SCARG(uap, tid); 637 int signum = SCARG(uap, signum); 638 void *tcb; 639 640 if (((u_int)signum) >= NSIG) 641 return (EINVAL); 642 if (tid > THREAD_PID_OFFSET) { 643 if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL) 644 return (ESRCH); 645 646 /* can only kill threads in the same process */ 647 if (p->p_p != cp->p_p) 648 return (ESRCH); 649 } else if (tid == 0) 650 p = cp; 651 else 652 return (EINVAL); 653 654 /* optionally require the target thread to have the given tcb addr */ 655 tcb = SCARG(uap, tcb); 656 if (tcb != NULL && tcb != TCB_GET(p)) 657 return (ESRCH); 658 659 if (signum) 660 ptsignal(p, signum, STHREAD); 661 return (0); 662 } 663 664 /* 665 * Common code for kill process group/broadcast kill. 666 * cp is calling process. 667 */ 668 int 669 killpg1(struct proc *cp, int signum, int pgid, int all) 670 { 671 struct process *pr; 672 struct pgrp *pgrp; 673 int nfound = 0; 674 675 if (all) { 676 /* 677 * broadcast 678 */ 679 LIST_FOREACH(pr, &allprocess, ps_list) { 680 if (pr->ps_pid <= 1 || 681 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 682 pr == cp->p_p || !cansignal(cp, pr, signum)) 683 continue; 684 nfound++; 685 if (signum) 686 prsignal(pr, signum); 687 } 688 } else { 689 if (pgid == 0) 690 /* 691 * zero pgid means send to my process group. 692 */ 693 pgrp = cp->p_p->ps_pgrp; 694 else { 695 pgrp = pgfind(pgid); 696 if (pgrp == NULL) 697 return (ESRCH); 698 } 699 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 700 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 701 !cansignal(cp, pr, signum)) 702 continue; 703 nfound++; 704 if (signum) 705 prsignal(pr, signum); 706 } 707 } 708 return (nfound ? 0 : ESRCH); 709 } 710 711 #define CANDELIVER(uid, euid, pr) \ 712 (euid == 0 || \ 713 (uid) == (pr)->ps_ucred->cr_ruid || \ 714 (uid) == (pr)->ps_ucred->cr_svuid || \ 715 (uid) == (pr)->ps_ucred->cr_uid || \ 716 (euid) == (pr)->ps_ucred->cr_ruid || \ 717 (euid) == (pr)->ps_ucred->cr_svuid || \ 718 (euid) == (pr)->ps_ucred->cr_uid) 719 720 #define CANSIGIO(cr, pr) \ 721 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 722 723 /* 724 * Send a signal to a process group. If checktty is 1, 725 * limit to members which have a controlling terminal. 726 */ 727 void 728 pgsignal(struct pgrp *pgrp, int signum, int checkctty) 729 { 730 struct process *pr; 731 732 if (pgrp) 733 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 734 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 735 prsignal(pr, signum); 736 } 737 738 /* 739 * Send a SIGIO or SIGURG signal to a process or process group using stored 740 * credentials rather than those of the current process. 741 */ 742 void 743 pgsigio(struct sigio_ref *sir, int sig, int checkctty) 744 { 745 struct process *pr; 746 struct sigio *sigio; 747 748 if (sir->sir_sigio == NULL) 749 return; 750 751 KERNEL_LOCK(); 752 mtx_enter(&sigio_lock); 753 sigio = sir->sir_sigio; 754 if (sigio == NULL) 755 goto out; 756 if (sigio->sio_pgid > 0) { 757 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 758 prsignal(sigio->sio_proc, sig); 759 } else if (sigio->sio_pgid < 0) { 760 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 761 if (CANSIGIO(sigio->sio_ucred, pr) && 762 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 763 prsignal(pr, sig); 764 } 765 } 766 out: 767 mtx_leave(&sigio_lock); 768 KERNEL_UNLOCK(); 769 } 770 771 /* 772 * Recalculate the signal mask and reset the signal disposition after 773 * usermode frame for delivery is formed. 774 */ 775 void 776 postsig_done(struct proc *p, int signum, struct sigacts *ps) 777 { 778 int mask = sigmask(signum); 779 780 KERNEL_ASSERT_LOCKED(); 781 782 p->p_ru.ru_nsignals++; 783 atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]); 784 if ((ps->ps_sigreset & mask) != 0) { 785 ps->ps_sigcatch &= ~mask; 786 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 787 ps->ps_sigignore |= mask; 788 ps->ps_sigact[signum] = SIG_DFL; 789 } 790 } 791 792 /* 793 * Send a signal caused by a trap to the current thread 794 * If it will be caught immediately, deliver it with correct code. 795 * Otherwise, post it normally. 796 */ 797 void 798 trapsignal(struct proc *p, int signum, u_long trapno, int code, 799 union sigval sigval) 800 { 801 struct process *pr = p->p_p; 802 struct sigacts *ps = pr->ps_sigacts; 803 int mask; 804 805 switch (signum) { 806 case SIGILL: 807 case SIGBUS: 808 case SIGSEGV: 809 pr->ps_acflag |= ATRAP; 810 break; 811 } 812 813 mask = sigmask(signum); 814 if ((pr->ps_flags & PS_TRACED) == 0 && 815 (ps->ps_sigcatch & mask) != 0 && 816 (p->p_sigmask & mask) == 0) { 817 siginfo_t si; 818 initsiginfo(&si, signum, trapno, code, sigval); 819 #ifdef KTRACE 820 if (KTRPOINT(p, KTR_PSIG)) { 821 ktrpsig(p, signum, ps->ps_sigact[signum], 822 p->p_sigmask, code, &si); 823 } 824 #endif 825 sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si); 826 postsig_done(p, signum, ps); 827 } else { 828 p->p_sisig = signum; 829 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 830 p->p_sicode = code; 831 p->p_sigval = sigval; 832 833 /* 834 * Signals like SIGBUS and SIGSEGV should not, when 835 * generated by the kernel, be ignorable or blockable. 836 * If it is and we're not being traced, then just kill 837 * the process. 838 */ 839 if ((pr->ps_flags & PS_TRACED) == 0 && 840 (sigprop[signum] & SA_KILL) && 841 ((p->p_sigmask & mask) || (ps->ps_sigignore & mask))) 842 sigexit(p, signum); 843 ptsignal(p, signum, STHREAD); 844 } 845 } 846 847 /* 848 * Send the signal to the process. If the signal has an action, the action 849 * is usually performed by the target process rather than the caller; we add 850 * the signal to the set of pending signals for the process. 851 * 852 * Exceptions: 853 * o When a stop signal is sent to a sleeping process that takes the 854 * default action, the process is stopped without awakening it. 855 * o SIGCONT restarts stopped processes (or puts them back to sleep) 856 * regardless of the signal action (eg, blocked or ignored). 857 * 858 * Other ignored signals are discarded immediately. 859 */ 860 void 861 psignal(struct proc *p, int signum) 862 { 863 ptsignal(p, signum, SPROCESS); 864 } 865 866 /* 867 * type = SPROCESS process signal, can be diverted (sigwait()) 868 * type = STHREAD thread signal, but should be propagated if unhandled 869 * type = SPROPAGATED propagated to this thread, so don't propagate again 870 */ 871 void 872 ptsignal(struct proc *p, int signum, enum signal_type type) 873 { 874 int s, prop; 875 sig_t action; 876 int mask; 877 int *siglist; 878 struct process *pr = p->p_p; 879 struct proc *q; 880 int wakeparent = 0; 881 882 KERNEL_ASSERT_LOCKED(); 883 884 #ifdef DIAGNOSTIC 885 if ((u_int)signum >= NSIG || signum == 0) 886 panic("psignal signal number"); 887 #endif 888 889 /* Ignore signal if the target process is exiting */ 890 if (pr->ps_flags & PS_EXITING) 891 return; 892 893 mask = sigmask(signum); 894 895 if (type == SPROCESS) { 896 /* Accept SIGKILL to coredumping processes */ 897 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 898 atomic_setbits_int(&pr->ps_siglist, mask); 899 return; 900 } 901 902 /* 903 * If the current thread can process the signal 904 * immediately (it's unblocked) then have it take it. 905 */ 906 q = curproc; 907 if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 908 (q->p_sigmask & mask) == 0) 909 p = q; 910 else { 911 /* 912 * A process-wide signal can be diverted to a 913 * different thread that's in sigwait() for this 914 * signal. If there isn't such a thread, then 915 * pick a thread that doesn't have it blocked so 916 * that the stop/kill consideration isn't 917 * delayed. Otherwise, mark it pending on the 918 * main thread. 919 */ 920 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 921 /* ignore exiting threads */ 922 if (q->p_flag & P_WEXIT) 923 continue; 924 925 /* skip threads that have the signal blocked */ 926 if ((q->p_sigmask & mask) != 0) 927 continue; 928 929 /* okay, could send to this thread */ 930 p = q; 931 932 /* 933 * sigsuspend, sigwait, ppoll/pselect, etc? 934 * Definitely go to this thread, as it's 935 * already blocked in the kernel. 936 */ 937 if (q->p_flag & P_SIGSUSPEND) 938 break; 939 } 940 } 941 } 942 943 if (type != SPROPAGATED) 944 KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum); 945 946 prop = sigprop[signum]; 947 948 /* 949 * If proc is traced, always give parent a chance. 950 */ 951 if (pr->ps_flags & PS_TRACED) { 952 action = SIG_DFL; 953 } else { 954 /* 955 * If the signal is being ignored, 956 * then we forget about it immediately. 957 * (Note: we don't set SIGCONT in ps_sigignore, 958 * and if it is set to SIG_IGN, 959 * action will be SIG_DFL here.) 960 */ 961 if (pr->ps_sigacts->ps_sigignore & mask) 962 return; 963 if (p->p_sigmask & mask) { 964 action = SIG_HOLD; 965 } else if (pr->ps_sigacts->ps_sigcatch & mask) { 966 action = SIG_CATCH; 967 } else { 968 action = SIG_DFL; 969 970 if (prop & SA_KILL && pr->ps_nice > NZERO) 971 pr->ps_nice = NZERO; 972 973 /* 974 * If sending a tty stop signal to a member of an 975 * orphaned process group, discard the signal here if 976 * the action is default; don't stop the process below 977 * if sleeping, and don't clear any pending SIGCONT. 978 */ 979 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 980 return; 981 } 982 } 983 /* 984 * If delivered to process, mark as pending there. Continue and stop 985 * signals will be propagated to all threads. So they are always 986 * marked at thread level. 987 */ 988 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 989 if (prop & SA_CONT) { 990 siglist = &p->p_siglist; 991 atomic_clearbits_int(siglist, stopsigmask); 992 } 993 if (prop & SA_STOP) { 994 siglist = &p->p_siglist; 995 atomic_clearbits_int(siglist, contsigmask); 996 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 997 } 998 atomic_setbits_int(siglist, mask); 999 1000 /* 1001 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1002 */ 1003 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1004 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1005 if (q != p) 1006 ptsignal(q, signum, SPROPAGATED); 1007 1008 /* 1009 * Defer further processing for signals which are held, 1010 * except that stopped processes must be continued by SIGCONT. 1011 */ 1012 if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) 1013 return; 1014 1015 SCHED_LOCK(s); 1016 1017 switch (p->p_stat) { 1018 1019 case SSLEEP: 1020 /* 1021 * If process is sleeping uninterruptibly 1022 * we can't interrupt the sleep... the signal will 1023 * be noticed when the process returns through 1024 * trap() or syscall(). 1025 */ 1026 if ((p->p_flag & P_SINTR) == 0) 1027 goto out; 1028 /* 1029 * Process is sleeping and traced... make it runnable 1030 * so it can discover the signal in issignal() and stop 1031 * for the parent. 1032 */ 1033 if (pr->ps_flags & PS_TRACED) 1034 goto run; 1035 /* 1036 * If SIGCONT is default (or ignored) and process is 1037 * asleep, we are finished; the process should not 1038 * be awakened. 1039 */ 1040 if ((prop & SA_CONT) && action == SIG_DFL) { 1041 atomic_clearbits_int(siglist, mask); 1042 goto out; 1043 } 1044 /* 1045 * When a sleeping process receives a stop 1046 * signal, process immediately if possible. 1047 */ 1048 if ((prop & SA_STOP) && action == SIG_DFL) { 1049 /* 1050 * If a child holding parent blocked, 1051 * stopping could cause deadlock. 1052 */ 1053 if (pr->ps_flags & PS_PPWAIT) 1054 goto out; 1055 atomic_clearbits_int(siglist, mask); 1056 pr->ps_xsig = signum; 1057 proc_stop(p, 0); 1058 goto out; 1059 } 1060 /* 1061 * All other (caught or default) signals 1062 * cause the process to run. 1063 */ 1064 goto runfast; 1065 /*NOTREACHED*/ 1066 1067 case SSTOP: 1068 /* 1069 * If traced process is already stopped, 1070 * then no further action is necessary. 1071 */ 1072 if (pr->ps_flags & PS_TRACED) 1073 goto out; 1074 1075 /* 1076 * Kill signal always sets processes running. 1077 */ 1078 if (signum == SIGKILL) { 1079 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1080 goto runfast; 1081 } 1082 1083 if (prop & SA_CONT) { 1084 /* 1085 * If SIGCONT is default (or ignored), we continue the 1086 * process but don't leave the signal in p_siglist, as 1087 * it has no further action. If SIGCONT is held, we 1088 * continue the process and leave the signal in 1089 * p_siglist. If the process catches SIGCONT, let it 1090 * handle the signal itself. If it isn't waiting on 1091 * an event, then it goes back to run state. 1092 * Otherwise, process goes back to sleep state. 1093 */ 1094 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1095 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1096 wakeparent = 1; 1097 if (action == SIG_DFL) 1098 atomic_clearbits_int(siglist, mask); 1099 if (action == SIG_CATCH) 1100 goto runfast; 1101 if (p->p_wchan == 0) 1102 goto run; 1103 p->p_stat = SSLEEP; 1104 goto out; 1105 } 1106 1107 if (prop & SA_STOP) { 1108 /* 1109 * Already stopped, don't need to stop again. 1110 * (If we did the shell could get confused.) 1111 */ 1112 atomic_clearbits_int(siglist, mask); 1113 goto out; 1114 } 1115 1116 /* 1117 * If process is sleeping interruptibly, then simulate a 1118 * wakeup so that when it is continued, it will be made 1119 * runnable and can look at the signal. But don't make 1120 * the process runnable, leave it stopped. 1121 */ 1122 if (p->p_flag & P_SINTR) 1123 unsleep(p); 1124 goto out; 1125 1126 case SONPROC: 1127 signotify(p); 1128 /* FALLTHROUGH */ 1129 default: 1130 /* 1131 * SRUN, SIDL, SDEAD do nothing with the signal, 1132 * other than kicking ourselves if we are running. 1133 * It will either never be noticed, or noticed very soon. 1134 */ 1135 goto out; 1136 } 1137 /*NOTREACHED*/ 1138 1139 runfast: 1140 /* 1141 * Raise priority to at least PUSER. 1142 */ 1143 if (p->p_usrpri > PUSER) 1144 p->p_usrpri = PUSER; 1145 run: 1146 setrunnable(p); 1147 out: 1148 SCHED_UNLOCK(s); 1149 if (wakeparent) 1150 wakeup(pr->ps_pptr); 1151 } 1152 1153 /* 1154 * If the current process has received a signal (should be caught or cause 1155 * termination, should interrupt current syscall), return the signal number. 1156 * Stop signals with default action are processed immediately, then cleared; 1157 * they aren't returned. This is checked after each entry to the system for 1158 * a syscall or trap (though this can usually be done without calling issignal 1159 * by checking the pending signal masks in the CURSIG macro.) The normal call 1160 * sequence is 1161 * 1162 * while (signum = CURSIG(curproc)) 1163 * postsig(signum); 1164 * 1165 * Assumes that if the P_SINTR flag is set, we're holding both the 1166 * kernel and scheduler locks. 1167 */ 1168 int 1169 issignal(struct proc *p) 1170 { 1171 struct process *pr = p->p_p; 1172 int signum, mask, prop; 1173 int dolock = (p->p_flag & P_SINTR) == 0; 1174 int s; 1175 1176 for (;;) { 1177 mask = SIGPENDING(p); 1178 if (pr->ps_flags & PS_PPWAIT) 1179 mask &= ~stopsigmask; 1180 if (mask == 0) /* no signal to send */ 1181 return (0); 1182 signum = ffs((long)mask); 1183 mask = sigmask(signum); 1184 atomic_clearbits_int(&p->p_siglist, mask); 1185 atomic_clearbits_int(&pr->ps_siglist, mask); 1186 1187 /* 1188 * We should see pending but ignored signals 1189 * only if PS_TRACED was on when they were posted. 1190 */ 1191 if (mask & pr->ps_sigacts->ps_sigignore && 1192 (pr->ps_flags & PS_TRACED) == 0) 1193 continue; 1194 1195 /* 1196 * If traced, always stop, and stay stopped until released 1197 * by the debugger. If our parent process is waiting for 1198 * us, don't hang as we could deadlock. 1199 */ 1200 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1201 signum != SIGKILL) { 1202 pr->ps_xsig = signum; 1203 1204 if (dolock) 1205 KERNEL_LOCK(); 1206 single_thread_set(p, SINGLE_PTRACE, 0); 1207 if (dolock) 1208 KERNEL_UNLOCK(); 1209 1210 if (dolock) 1211 SCHED_LOCK(s); 1212 proc_stop(p, 1); 1213 if (dolock) 1214 SCHED_UNLOCK(s); 1215 1216 if (dolock) 1217 KERNEL_LOCK(); 1218 single_thread_clear(p, 0); 1219 if (dolock) 1220 KERNEL_UNLOCK(); 1221 1222 /* 1223 * If we are no longer being traced, or the parent 1224 * didn't give us a signal, look for more signals. 1225 */ 1226 if ((pr->ps_flags & PS_TRACED) == 0 || 1227 pr->ps_xsig == 0) 1228 continue; 1229 1230 /* 1231 * If the new signal is being masked, look for other 1232 * signals. 1233 */ 1234 signum = pr->ps_xsig; 1235 mask = sigmask(signum); 1236 if ((p->p_sigmask & mask) != 0) 1237 continue; 1238 1239 /* take the signal! */ 1240 atomic_clearbits_int(&p->p_siglist, mask); 1241 atomic_clearbits_int(&pr->ps_siglist, mask); 1242 } 1243 1244 prop = sigprop[signum]; 1245 1246 /* 1247 * Decide whether the signal should be returned. 1248 * Return the signal's number, or fall through 1249 * to clear it from the pending mask. 1250 */ 1251 switch ((long)pr->ps_sigacts->ps_sigact[signum]) { 1252 case (long)SIG_DFL: 1253 /* 1254 * Don't take default actions on system processes. 1255 */ 1256 if (pr->ps_pid <= 1) { 1257 #ifdef DIAGNOSTIC 1258 /* 1259 * Are you sure you want to ignore SIGSEGV 1260 * in init? XXX 1261 */ 1262 printf("Process (pid %d) got signal" 1263 " %d\n", pr->ps_pid, signum); 1264 #endif 1265 break; /* == ignore */ 1266 } 1267 /* 1268 * If there is a pending stop signal to process 1269 * with default action, stop here, 1270 * then clear the signal. However, 1271 * if process is member of an orphaned 1272 * process group, ignore tty stop signals. 1273 */ 1274 if (prop & SA_STOP) { 1275 if (pr->ps_flags & PS_TRACED || 1276 (pr->ps_pgrp->pg_jobc == 0 && 1277 prop & SA_TTYSTOP)) 1278 break; /* == ignore */ 1279 pr->ps_xsig = signum; 1280 if (dolock) 1281 SCHED_LOCK(s); 1282 proc_stop(p, 1); 1283 if (dolock) 1284 SCHED_UNLOCK(s); 1285 break; 1286 } else if (prop & SA_IGNORE) { 1287 /* 1288 * Except for SIGCONT, shouldn't get here. 1289 * Default action is to ignore; drop it. 1290 */ 1291 break; /* == ignore */ 1292 } else 1293 goto keep; 1294 /*NOTREACHED*/ 1295 case (long)SIG_IGN: 1296 /* 1297 * Masking above should prevent us ever trying 1298 * to take action on an ignored signal other 1299 * than SIGCONT, unless process is traced. 1300 */ 1301 if ((prop & SA_CONT) == 0 && 1302 (pr->ps_flags & PS_TRACED) == 0) 1303 printf("issignal\n"); 1304 break; /* == ignore */ 1305 default: 1306 /* 1307 * This signal has an action, let 1308 * postsig() process it. 1309 */ 1310 goto keep; 1311 } 1312 } 1313 /* NOTREACHED */ 1314 1315 keep: 1316 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1317 return (signum); 1318 } 1319 1320 /* 1321 * Put the argument process into the stopped state and notify the parent 1322 * via wakeup. Signals are handled elsewhere. The process must not be 1323 * on the run queue. 1324 */ 1325 void 1326 proc_stop(struct proc *p, int sw) 1327 { 1328 struct process *pr = p->p_p; 1329 1330 #ifdef MULTIPROCESSOR 1331 SCHED_ASSERT_LOCKED(); 1332 #endif 1333 1334 p->p_stat = SSTOP; 1335 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1336 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1337 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1338 /* 1339 * We need this soft interrupt to be handled fast. 1340 * Extra calls to softclock don't hurt. 1341 */ 1342 softintr_schedule(proc_stop_si); 1343 if (sw) 1344 mi_switch(); 1345 } 1346 1347 /* 1348 * Called from a soft interrupt to send signals to the parents of stopped 1349 * processes. 1350 * We can't do this in proc_stop because it's called with nasty locks held 1351 * and we would need recursive scheduler lock to deal with that. 1352 */ 1353 void 1354 proc_stop_sweep(void *v) 1355 { 1356 struct process *pr; 1357 1358 LIST_FOREACH(pr, &allprocess, ps_list) { 1359 if ((pr->ps_flags & PS_STOPPED) == 0) 1360 continue; 1361 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1362 1363 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1364 prsignal(pr->ps_pptr, SIGCHLD); 1365 wakeup(pr->ps_pptr); 1366 } 1367 } 1368 1369 /* 1370 * Take the action for the specified signal 1371 * from the current set of pending signals. 1372 */ 1373 void 1374 postsig(struct proc *p, int signum) 1375 { 1376 struct process *pr = p->p_p; 1377 struct sigacts *ps = pr->ps_sigacts; 1378 sig_t action; 1379 u_long trapno; 1380 int mask, returnmask; 1381 siginfo_t si; 1382 union sigval sigval; 1383 int s, code; 1384 1385 KASSERT(signum != 0); 1386 KERNEL_ASSERT_LOCKED(); 1387 1388 mask = sigmask(signum); 1389 atomic_clearbits_int(&p->p_siglist, mask); 1390 action = ps->ps_sigact[signum]; 1391 sigval.sival_ptr = 0; 1392 1393 if (p->p_sisig != signum) { 1394 trapno = 0; 1395 code = SI_USER; 1396 sigval.sival_ptr = 0; 1397 } else { 1398 trapno = p->p_sitrapno; 1399 code = p->p_sicode; 1400 sigval = p->p_sigval; 1401 } 1402 initsiginfo(&si, signum, trapno, code, sigval); 1403 1404 #ifdef KTRACE 1405 if (KTRPOINT(p, KTR_PSIG)) { 1406 ktrpsig(p, signum, action, p->p_flag & P_SIGSUSPEND ? 1407 p->p_oldmask : p->p_sigmask, code, &si); 1408 } 1409 #endif 1410 if (action == SIG_DFL) { 1411 /* 1412 * Default action, where the default is to kill 1413 * the process. (Other cases were ignored above.) 1414 */ 1415 sigexit(p, signum); 1416 /* NOTREACHED */ 1417 } else { 1418 /* 1419 * If we get here, the signal must be caught. 1420 */ 1421 #ifdef DIAGNOSTIC 1422 if (action == SIG_IGN || (p->p_sigmask & mask)) 1423 panic("postsig action"); 1424 #endif 1425 /* 1426 * Set the new mask value and also defer further 1427 * occurrences of this signal. 1428 * 1429 * Special case: user has done a sigpause. Here the 1430 * current mask is not of interest, but rather the 1431 * mask from before the sigpause is what we want 1432 * restored after the signal processing is completed. 1433 */ 1434 #ifdef MULTIPROCESSOR 1435 s = splsched(); 1436 #else 1437 s = splhigh(); 1438 #endif 1439 if (p->p_flag & P_SIGSUSPEND) { 1440 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1441 returnmask = p->p_oldmask; 1442 } else { 1443 returnmask = p->p_sigmask; 1444 } 1445 if (p->p_sisig == signum) { 1446 p->p_sisig = 0; 1447 p->p_sitrapno = 0; 1448 p->p_sicode = SI_USER; 1449 p->p_sigval.sival_ptr = NULL; 1450 } 1451 1452 sendsig(action, signum, returnmask, &si); 1453 postsig_done(p, signum, ps); 1454 splx(s); 1455 } 1456 } 1457 1458 /* 1459 * Force the current process to exit with the specified signal, dumping core 1460 * if appropriate. We bypass the normal tests for masked and caught signals, 1461 * allowing unrecoverable failures to terminate the process without changing 1462 * signal state. Mark the accounting record with the signal termination. 1463 * If dumping core, save the signal number for the debugger. Calls exit and 1464 * does not return. 1465 */ 1466 void 1467 sigexit(struct proc *p, int signum) 1468 { 1469 /* Mark process as going away */ 1470 atomic_setbits_int(&p->p_flag, P_WEXIT); 1471 1472 p->p_p->ps_acflag |= AXSIG; 1473 if (sigprop[signum] & SA_CORE) { 1474 p->p_sisig = signum; 1475 1476 /* if there are other threads, pause them */ 1477 if (P_HASSIBLING(p)) 1478 single_thread_set(p, SINGLE_SUSPEND, 0); 1479 1480 if (coredump(p) == 0) 1481 signum |= WCOREFLAG; 1482 } 1483 exit1(p, 0, signum, EXIT_NORMAL); 1484 /* NOTREACHED */ 1485 } 1486 1487 int nosuidcoredump = 1; 1488 1489 struct coredump_iostate { 1490 struct proc *io_proc; 1491 struct vnode *io_vp; 1492 struct ucred *io_cred; 1493 off_t io_offset; 1494 }; 1495 1496 /* 1497 * Dump core, into a file named "progname.core", unless the process was 1498 * setuid/setgid. 1499 */ 1500 int 1501 coredump(struct proc *p) 1502 { 1503 #ifdef SMALL_KERNEL 1504 return EPERM; 1505 #else 1506 struct process *pr = p->p_p; 1507 struct vnode *vp; 1508 struct ucred *cred = p->p_ucred; 1509 struct vmspace *vm = p->p_vmspace; 1510 struct nameidata nd; 1511 struct vattr vattr; 1512 struct coredump_iostate io; 1513 int error, len, incrash = 0; 1514 char *name; 1515 const char *dir = "/var/crash"; 1516 1517 if (pr->ps_emul->e_coredump == NULL) 1518 return (EINVAL); 1519 1520 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1521 1522 /* Don't dump if will exceed file size limit. */ 1523 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1524 return (EFBIG); 1525 1526 name = pool_get(&namei_pool, PR_WAITOK); 1527 1528 /* 1529 * If the process has inconsistent uids, nosuidcoredump 1530 * determines coredump placement policy. 1531 */ 1532 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1533 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1534 if (nosuidcoredump == 3) { 1535 /* 1536 * If the program directory does not exist, dumps of 1537 * that core will silently fail. 1538 */ 1539 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1540 dir, pr->ps_comm, pr->ps_pid); 1541 incrash = KERNELPATH; 1542 } else if (nosuidcoredump == 2) { 1543 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1544 dir, pr->ps_comm); 1545 incrash = KERNELPATH; 1546 } else { 1547 pool_put(&namei_pool, name); 1548 return (EPERM); 1549 } 1550 } else 1551 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1552 1553 if (len >= MAXPATHLEN) { 1554 pool_put(&namei_pool, name); 1555 return (EACCES); 1556 } 1557 1558 /* 1559 * Control the UID used to write out. The normal case uses 1560 * the real UID. If the sugid case is going to write into the 1561 * controlled directory, we do so as root. 1562 */ 1563 if (incrash == 0) { 1564 cred = crdup(cred); 1565 cred->cr_uid = cred->cr_ruid; 1566 cred->cr_gid = cred->cr_rgid; 1567 } else { 1568 if (p->p_fd->fd_rdir) { 1569 vrele(p->p_fd->fd_rdir); 1570 p->p_fd->fd_rdir = NULL; 1571 } 1572 p->p_ucred = crdup(p->p_ucred); 1573 crfree(cred); 1574 cred = p->p_ucred; 1575 crhold(cred); 1576 cred->cr_uid = 0; 1577 cred->cr_gid = 0; 1578 } 1579 1580 /* incrash should be 0 or KERNELPATH only */ 1581 NDINIT(&nd, 0, incrash, UIO_SYSSPACE, name, p); 1582 1583 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1584 S_IRUSR | S_IWUSR); 1585 1586 if (error) 1587 goto out; 1588 1589 /* 1590 * Don't dump to non-regular files, files with links, or files 1591 * owned by someone else. 1592 */ 1593 vp = nd.ni_vp; 1594 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1595 VOP_UNLOCK(vp); 1596 vn_close(vp, FWRITE, cred, p); 1597 goto out; 1598 } 1599 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1600 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1601 vattr.va_uid != cred->cr_uid) { 1602 error = EACCES; 1603 VOP_UNLOCK(vp); 1604 vn_close(vp, FWRITE, cred, p); 1605 goto out; 1606 } 1607 VATTR_NULL(&vattr); 1608 vattr.va_size = 0; 1609 VOP_SETATTR(vp, &vattr, cred, p); 1610 pr->ps_acflag |= ACORE; 1611 1612 io.io_proc = p; 1613 io.io_vp = vp; 1614 io.io_cred = cred; 1615 io.io_offset = 0; 1616 VOP_UNLOCK(vp); 1617 vref(vp); 1618 error = vn_close(vp, FWRITE, cred, p); 1619 if (error == 0) 1620 error = (*pr->ps_emul->e_coredump)(p, &io); 1621 vrele(vp); 1622 out: 1623 crfree(cred); 1624 pool_put(&namei_pool, name); 1625 return (error); 1626 #endif 1627 } 1628 1629 #ifndef SMALL_KERNEL 1630 int 1631 coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) 1632 { 1633 struct coredump_iostate *io = cookie; 1634 off_t coffset = 0; 1635 size_t csize; 1636 int chunk, error; 1637 1638 csize = len; 1639 do { 1640 if (sigmask(SIGKILL) & 1641 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1642 return (EINTR); 1643 1644 /* Rest of the loop sleeps with lock held, so... */ 1645 yield(); 1646 1647 chunk = MIN(csize, MAXPHYS); 1648 error = vn_rdwr(UIO_WRITE, io->io_vp, 1649 (caddr_t)data + coffset, chunk, 1650 io->io_offset + coffset, segflg, 1651 IO_UNIT, io->io_cred, NULL, io->io_proc); 1652 if (error) { 1653 struct process *pr = io->io_proc->p_p; 1654 1655 if (error == ENOSPC) 1656 log(LOG_ERR, 1657 "coredump of %s(%d) failed, filesystem full\n", 1658 pr->ps_comm, pr->ps_pid); 1659 else 1660 log(LOG_ERR, 1661 "coredump of %s(%d), write failed: errno %d\n", 1662 pr->ps_comm, pr->ps_pid, error); 1663 return (error); 1664 } 1665 1666 coffset += chunk; 1667 csize -= chunk; 1668 } while (csize > 0); 1669 1670 io->io_offset += len; 1671 return (0); 1672 } 1673 1674 void 1675 coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1676 { 1677 struct coredump_iostate *io = cookie; 1678 1679 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1680 } 1681 1682 #endif /* !SMALL_KERNEL */ 1683 1684 /* 1685 * Nonexistent system call-- signal process (may want to handle it). 1686 * Flag error in case process won't see signal immediately (blocked or ignored). 1687 */ 1688 int 1689 sys_nosys(struct proc *p, void *v, register_t *retval) 1690 { 1691 1692 ptsignal(p, SIGSYS, STHREAD); 1693 return (ENOSYS); 1694 } 1695 1696 int 1697 sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1698 { 1699 static int sigwaitsleep; 1700 struct sys___thrsigdivert_args /* { 1701 syscallarg(sigset_t) sigmask; 1702 syscallarg(siginfo_t *) info; 1703 syscallarg(const struct timespec *) timeout; 1704 } */ *uap = v; 1705 struct process *pr = p->p_p; 1706 sigset_t *m; 1707 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1708 siginfo_t si; 1709 uint64_t nsecs = INFSLP; 1710 int timeinvalid = 0; 1711 int error = 0; 1712 1713 memset(&si, 0, sizeof(si)); 1714 1715 if (SCARG(uap, timeout) != NULL) { 1716 struct timespec ts; 1717 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1718 return (error); 1719 #ifdef KTRACE 1720 if (KTRPOINT(p, KTR_STRUCT)) 1721 ktrreltimespec(p, &ts); 1722 #endif 1723 if (!timespecisvalid(&ts)) 1724 timeinvalid = 1; 1725 else 1726 nsecs = TIMESPEC_TO_NSEC(&ts); 1727 } 1728 1729 dosigsuspend(p, p->p_sigmask &~ mask); 1730 for (;;) { 1731 si.si_signo = CURSIG(p); 1732 if (si.si_signo != 0) { 1733 sigset_t smask = sigmask(si.si_signo); 1734 if (smask & mask) { 1735 if (p->p_siglist & smask) 1736 m = &p->p_siglist; 1737 else if (pr->ps_siglist & smask) 1738 m = &pr->ps_siglist; 1739 else { 1740 /* signal got eaten by someone else? */ 1741 continue; 1742 } 1743 atomic_clearbits_int(m, smask); 1744 error = 0; 1745 break; 1746 } 1747 } 1748 1749 /* per-POSIX, delay this error until after the above */ 1750 if (timeinvalid) 1751 error = EINVAL; 1752 1753 if (SCARG(uap, timeout) != NULL && nsecs == INFSLP) 1754 error = EAGAIN; 1755 1756 if (error != 0) 1757 break; 1758 1759 error = tsleep_nsec(&sigwaitsleep, PPAUSE|PCATCH, "sigwait", 1760 nsecs); 1761 } 1762 1763 if (error == 0) { 1764 *retval = si.si_signo; 1765 if (SCARG(uap, info) != NULL) 1766 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1767 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1768 /* 1769 * Restarting is wrong if there's a timeout, as it'll be 1770 * for the same interval again 1771 */ 1772 error = EINTR; 1773 } 1774 1775 return (error); 1776 } 1777 1778 void 1779 initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1780 { 1781 memset(si, 0, sizeof(*si)); 1782 1783 si->si_signo = sig; 1784 si->si_code = code; 1785 if (code == SI_USER) { 1786 si->si_value = val; 1787 } else { 1788 switch (sig) { 1789 case SIGSEGV: 1790 case SIGILL: 1791 case SIGBUS: 1792 case SIGFPE: 1793 si->si_addr = val.sival_ptr; 1794 si->si_trapno = trapno; 1795 break; 1796 case SIGXFSZ: 1797 break; 1798 } 1799 } 1800 } 1801 1802 int 1803 filt_sigattach(struct knote *kn) 1804 { 1805 struct process *pr = curproc->p_p; 1806 int s; 1807 1808 if (kn->kn_id >= NSIG) 1809 return EINVAL; 1810 1811 kn->kn_ptr.p_process = pr; 1812 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1813 1814 s = splhigh(); 1815 klist_insert(&pr->ps_klist, kn); 1816 splx(s); 1817 1818 return (0); 1819 } 1820 1821 void 1822 filt_sigdetach(struct knote *kn) 1823 { 1824 struct process *pr = kn->kn_ptr.p_process; 1825 int s; 1826 1827 s = splhigh(); 1828 klist_remove(&pr->ps_klist, kn); 1829 splx(s); 1830 } 1831 1832 /* 1833 * signal knotes are shared with proc knotes, so we apply a mask to 1834 * the hint in order to differentiate them from process hints. This 1835 * could be avoided by using a signal-specific knote list, but probably 1836 * isn't worth the trouble. 1837 */ 1838 int 1839 filt_signal(struct knote *kn, long hint) 1840 { 1841 1842 if (hint & NOTE_SIGNAL) { 1843 hint &= ~NOTE_SIGNAL; 1844 1845 if (kn->kn_id == hint) 1846 kn->kn_data++; 1847 } 1848 return (kn->kn_data != 0); 1849 } 1850 1851 void 1852 userret(struct proc *p) 1853 { 1854 int signum; 1855 1856 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 1857 if (p->p_flag & P_PROFPEND) { 1858 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 1859 KERNEL_LOCK(); 1860 psignal(p, SIGPROF); 1861 KERNEL_UNLOCK(); 1862 } 1863 if (p->p_flag & P_ALRMPEND) { 1864 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 1865 KERNEL_LOCK(); 1866 psignal(p, SIGVTALRM); 1867 KERNEL_UNLOCK(); 1868 } 1869 1870 if (SIGPENDING(p) != 0) { 1871 KERNEL_LOCK(); 1872 while ((signum = CURSIG(p)) != 0) 1873 postsig(p, signum); 1874 KERNEL_UNLOCK(); 1875 } 1876 1877 /* 1878 * If P_SIGSUSPEND is still set here, then we still need to restore 1879 * the original sigmask before returning to userspace. Also, this 1880 * might unmask some pending signals, so we need to check a second 1881 * time for signals to post. 1882 */ 1883 if (p->p_flag & P_SIGSUSPEND) { 1884 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1885 p->p_sigmask = p->p_oldmask; 1886 1887 KERNEL_LOCK(); 1888 while ((signum = CURSIG(p)) != 0) 1889 postsig(p, signum); 1890 KERNEL_UNLOCK(); 1891 } 1892 1893 if (p->p_flag & P_SUSPSINGLE) 1894 single_thread_check(p, 0); 1895 1896 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 1897 1898 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 1899 } 1900 1901 int 1902 single_thread_check(struct proc *p, int deep) 1903 { 1904 struct process *pr = p->p_p; 1905 1906 if (pr->ps_single != NULL && pr->ps_single != p) { 1907 do { 1908 int s; 1909 1910 /* if we're in deep, we need to unwind to the edge */ 1911 if (deep) { 1912 if (pr->ps_flags & PS_SINGLEUNWIND) 1913 return (ERESTART); 1914 if (pr->ps_flags & PS_SINGLEEXIT) 1915 return (EINTR); 1916 } 1917 1918 if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) 1919 wakeup(&pr->ps_singlecount); 1920 if (pr->ps_flags & PS_SINGLEEXIT) { 1921 KERNEL_LOCK(); 1922 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 1923 KERNEL_UNLOCK(); 1924 } 1925 1926 /* not exiting and don't need to unwind, so suspend */ 1927 SCHED_LOCK(s); 1928 p->p_stat = SSTOP; 1929 mi_switch(); 1930 SCHED_UNLOCK(s); 1931 } while (pr->ps_single != NULL); 1932 } 1933 1934 return (0); 1935 } 1936 1937 /* 1938 * Stop other threads in the process. The mode controls how and 1939 * where the other threads should stop: 1940 * - SINGLE_SUSPEND: stop wherever they are, will later either be told to exit 1941 * (by setting to SINGLE_EXIT) or be released (via single_thread_clear()) 1942 * - SINGLE_PTRACE: stop wherever they are, will wait for them to stop 1943 * later (via single_thread_wait()) and released as with SINGLE_SUSPEND 1944 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 1945 * or released as with SINGLE_SUSPEND 1946 * - SINGLE_EXIT: unwind to kernel boundary and exit 1947 */ 1948 int 1949 single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) 1950 { 1951 struct process *pr = p->p_p; 1952 struct proc *q; 1953 int error; 1954 1955 KERNEL_ASSERT_LOCKED(); 1956 KASSERT(curproc == p); 1957 1958 if ((error = single_thread_check(p, deep))) 1959 return error; 1960 1961 switch (mode) { 1962 case SINGLE_SUSPEND: 1963 case SINGLE_PTRACE: 1964 break; 1965 case SINGLE_UNWIND: 1966 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1967 break; 1968 case SINGLE_EXIT: 1969 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 1970 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 1971 break; 1972 #ifdef DIAGNOSTIC 1973 default: 1974 panic("single_thread_mode = %d", mode); 1975 #endif 1976 } 1977 pr->ps_singlecount = 0; 1978 membar_producer(); 1979 pr->ps_single = p; 1980 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 1981 int s; 1982 1983 if (q == p) 1984 continue; 1985 if (q->p_flag & P_WEXIT) { 1986 if (mode == SINGLE_EXIT) { 1987 SCHED_LOCK(s); 1988 if (q->p_stat == SSTOP) { 1989 setrunnable(q); 1990 atomic_inc_int(&pr->ps_singlecount); 1991 } 1992 SCHED_UNLOCK(s); 1993 } 1994 continue; 1995 } 1996 SCHED_LOCK(s); 1997 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 1998 switch (q->p_stat) { 1999 case SIDL: 2000 case SRUN: 2001 atomic_inc_int(&pr->ps_singlecount); 2002 break; 2003 case SSLEEP: 2004 /* if it's not interruptible, then just have to wait */ 2005 if (q->p_flag & P_SINTR) { 2006 /* merely need to suspend? just stop it */ 2007 if (mode == SINGLE_SUSPEND || 2008 mode == SINGLE_PTRACE) { 2009 q->p_stat = SSTOP; 2010 break; 2011 } 2012 /* need to unwind or exit, so wake it */ 2013 setrunnable(q); 2014 } 2015 atomic_inc_int(&pr->ps_singlecount); 2016 break; 2017 case SSTOP: 2018 if (mode == SINGLE_EXIT) { 2019 setrunnable(q); 2020 atomic_inc_int(&pr->ps_singlecount); 2021 } 2022 break; 2023 case SDEAD: 2024 break; 2025 case SONPROC: 2026 atomic_inc_int(&pr->ps_singlecount); 2027 signotify(q); 2028 break; 2029 } 2030 SCHED_UNLOCK(s); 2031 } 2032 2033 if (mode != SINGLE_PTRACE) 2034 single_thread_wait(pr, 1); 2035 2036 return 0; 2037 } 2038 2039 /* 2040 * Wait for other threads to stop. If recheck is false then the function 2041 * returns non-zero if the caller needs to restart the check else 0 is 2042 * returned. If recheck is true the return value is always 0. 2043 */ 2044 int 2045 single_thread_wait(struct process *pr, int recheck) 2046 { 2047 struct sleep_state sls; 2048 int wait; 2049 2050 /* wait until they're all suspended */ 2051 wait = pr->ps_singlecount > 0; 2052 while (wait) { 2053 sleep_setup(&sls, &pr->ps_singlecount, PWAIT, "suspend"); 2054 wait = pr->ps_singlecount > 0; 2055 sleep_finish(&sls, wait); 2056 if (!recheck) 2057 break; 2058 } 2059 2060 return wait; 2061 } 2062 2063 void 2064 single_thread_clear(struct proc *p, int flag) 2065 { 2066 struct process *pr = p->p_p; 2067 struct proc *q; 2068 2069 KASSERT(pr->ps_single == p); 2070 KASSERT(curproc == p); 2071 KERNEL_ASSERT_LOCKED(); 2072 2073 pr->ps_single = NULL; 2074 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2075 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2076 int s; 2077 2078 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2079 continue; 2080 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2081 2082 /* 2083 * if the thread was only stopped for single threading 2084 * then clearing that either makes it runnable or puts 2085 * it back into some sleep queue 2086 */ 2087 SCHED_LOCK(s); 2088 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2089 if (q->p_wchan == 0) 2090 setrunnable(q); 2091 else 2092 q->p_stat = SSLEEP; 2093 } 2094 SCHED_UNLOCK(s); 2095 } 2096 } 2097 2098 void 2099 sigio_del(struct sigiolst *rmlist) 2100 { 2101 struct sigio *sigio; 2102 2103 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2104 LIST_REMOVE(sigio, sio_pgsigio); 2105 crfree(sigio->sio_ucred); 2106 free(sigio, M_SIGIO, sizeof(*sigio)); 2107 } 2108 } 2109 2110 void 2111 sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2112 { 2113 struct sigio *sigio; 2114 2115 MUTEX_ASSERT_LOCKED(&sigio_lock); 2116 2117 sigio = sir->sir_sigio; 2118 if (sigio != NULL) { 2119 KASSERT(sigio->sio_myref == sir); 2120 sir->sir_sigio = NULL; 2121 2122 if (sigio->sio_pgid > 0) 2123 sigio->sio_proc = NULL; 2124 else 2125 sigio->sio_pgrp = NULL; 2126 LIST_REMOVE(sigio, sio_pgsigio); 2127 2128 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2129 } 2130 } 2131 2132 void 2133 sigio_free(struct sigio_ref *sir) 2134 { 2135 struct sigiolst rmlist; 2136 2137 if (sir->sir_sigio == NULL) 2138 return; 2139 2140 LIST_INIT(&rmlist); 2141 2142 mtx_enter(&sigio_lock); 2143 sigio_unlink(sir, &rmlist); 2144 mtx_leave(&sigio_lock); 2145 2146 sigio_del(&rmlist); 2147 } 2148 2149 void 2150 sigio_freelist(struct sigiolst *sigiolst) 2151 { 2152 struct sigiolst rmlist; 2153 struct sigio *sigio; 2154 2155 if (LIST_EMPTY(sigiolst)) 2156 return; 2157 2158 LIST_INIT(&rmlist); 2159 2160 mtx_enter(&sigio_lock); 2161 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2162 sigio_unlink(sigio->sio_myref, &rmlist); 2163 mtx_leave(&sigio_lock); 2164 2165 sigio_del(&rmlist); 2166 } 2167 2168 int 2169 sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2170 { 2171 struct sigiolst rmlist; 2172 struct proc *p = curproc; 2173 struct pgrp *pgrp = NULL; 2174 struct process *pr = NULL; 2175 struct sigio *sigio; 2176 int error; 2177 pid_t pgid = *(int *)data; 2178 2179 if (pgid == 0) { 2180 sigio_free(sir); 2181 return (0); 2182 } 2183 2184 if (cmd == TIOCSPGRP) { 2185 if (pgid < 0) 2186 return (EINVAL); 2187 pgid = -pgid; 2188 } 2189 2190 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2191 sigio->sio_pgid = pgid; 2192 sigio->sio_ucred = crhold(p->p_ucred); 2193 sigio->sio_myref = sir; 2194 2195 LIST_INIT(&rmlist); 2196 2197 /* 2198 * The kernel lock, and not sleeping between prfind()/pgfind() and 2199 * linking of the sigio ensure that the process or process group does 2200 * not disappear unexpectedly. 2201 */ 2202 KERNEL_LOCK(); 2203 mtx_enter(&sigio_lock); 2204 2205 if (pgid > 0) { 2206 pr = prfind(pgid); 2207 if (pr == NULL) { 2208 error = ESRCH; 2209 goto fail; 2210 } 2211 2212 /* 2213 * Policy - Don't allow a process to FSETOWN a process 2214 * in another session. 2215 * 2216 * Remove this test to allow maximum flexibility or 2217 * restrict FSETOWN to the current process or process 2218 * group for maximum safety. 2219 */ 2220 if (pr->ps_session != p->p_p->ps_session) { 2221 error = EPERM; 2222 goto fail; 2223 } 2224 2225 if ((pr->ps_flags & PS_EXITING) != 0) { 2226 error = ESRCH; 2227 goto fail; 2228 } 2229 } else /* if (pgid < 0) */ { 2230 pgrp = pgfind(-pgid); 2231 if (pgrp == NULL) { 2232 error = ESRCH; 2233 goto fail; 2234 } 2235 2236 /* 2237 * Policy - Don't allow a process to FSETOWN a process 2238 * in another session. 2239 * 2240 * Remove this test to allow maximum flexibility or 2241 * restrict FSETOWN to the current process or process 2242 * group for maximum safety. 2243 */ 2244 if (pgrp->pg_session != p->p_p->ps_session) { 2245 error = EPERM; 2246 goto fail; 2247 } 2248 } 2249 2250 if (pgid > 0) { 2251 sigio->sio_proc = pr; 2252 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2253 } else { 2254 sigio->sio_pgrp = pgrp; 2255 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2256 } 2257 2258 sigio_unlink(sir, &rmlist); 2259 sir->sir_sigio = sigio; 2260 2261 mtx_leave(&sigio_lock); 2262 KERNEL_UNLOCK(); 2263 2264 sigio_del(&rmlist); 2265 2266 return (0); 2267 2268 fail: 2269 mtx_leave(&sigio_lock); 2270 KERNEL_UNLOCK(); 2271 2272 crfree(sigio->sio_ucred); 2273 free(sigio, M_SIGIO, sizeof(*sigio)); 2274 2275 return (error); 2276 } 2277 2278 void 2279 sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2280 { 2281 struct sigio *sigio; 2282 pid_t pgid = 0; 2283 2284 mtx_enter(&sigio_lock); 2285 sigio = sir->sir_sigio; 2286 if (sigio != NULL) 2287 pgid = sigio->sio_pgid; 2288 mtx_leave(&sigio_lock); 2289 2290 if (cmd == TIOCGPGRP) 2291 pgid = -pgid; 2292 2293 *(int *)data = pgid; 2294 } 2295 2296 void 2297 sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2298 { 2299 struct sigiolst rmlist; 2300 struct sigio *newsigio, *sigio; 2301 2302 sigio_free(dst); 2303 2304 if (src->sir_sigio == NULL) 2305 return; 2306 2307 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2308 LIST_INIT(&rmlist); 2309 2310 mtx_enter(&sigio_lock); 2311 2312 sigio = src->sir_sigio; 2313 if (sigio == NULL) { 2314 mtx_leave(&sigio_lock); 2315 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2316 return; 2317 } 2318 2319 newsigio->sio_pgid = sigio->sio_pgid; 2320 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2321 newsigio->sio_myref = dst; 2322 if (newsigio->sio_pgid > 0) { 2323 newsigio->sio_proc = sigio->sio_proc; 2324 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2325 sio_pgsigio); 2326 } else { 2327 newsigio->sio_pgrp = sigio->sio_pgrp; 2328 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2329 sio_pgsigio); 2330 } 2331 2332 sigio_unlink(dst, &rmlist); 2333 dst->sir_sigio = newsigio; 2334 2335 mtx_leave(&sigio_lock); 2336 2337 sigio_del(&rmlist); 2338 } 2339