1/* $OpenBSD: kern_sig.c,v 1.330 2024/06/03 12:48:25 claudio Exp $ */ 2/* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ 3 4/* 5 * Copyright (c) 1997 Theo de Raadt. All rights reserved. 6 * Copyright (c) 1982, 1986, 1989, 1991, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 */ 40 41#include <sys/param.h> 42#include <sys/signalvar.h> 43#include <sys/queue.h> 44#include <sys/namei.h> 45#include <sys/vnode.h> 46#include <sys/event.h> 47#include <sys/proc.h> 48#include <sys/systm.h> 49#include <sys/acct.h> 50#include <sys/fcntl.h> 51#include <sys/filedesc.h> 52#include <sys/wait.h> 53#include <sys/ktrace.h> 54#include <sys/stat.h> 55#include <sys/malloc.h> 56#include <sys/pool.h> 57#include <sys/sched.h> 58#include <sys/user.h> 59#include <sys/syslog.h> 60#include <sys/ttycom.h> 61#include <sys/pledge.h> 62#include <sys/witness.h> 63#include <sys/exec_elf.h> 64 65#include <sys/mount.h> 66#include <sys/syscallargs.h> 67 68#include <uvm/uvm_extern.h> 69#include <machine/tcb.h> 70 71int nosuidcoredump = 1; 72 73int filt_sigattach(struct knote *kn); 74void filt_sigdetach(struct knote *kn); 75int filt_signal(struct knote *kn, long hint); 76 77const struct filterops sig_filtops = { 78 .f_flags = 0, 79 .f_attach = filt_sigattach, 80 .f_detach = filt_sigdetach, 81 .f_event = filt_signal, 82}; 83 84/* 85 * The array below categorizes the signals and their default actions. 86 */ 87const int sigprop[NSIG] = { 88 0, /* unused */ 89 SA_KILL, /* SIGHUP */ 90 SA_KILL, /* SIGINT */ 91 SA_KILL|SA_CORE, /* SIGQUIT */ 92 SA_KILL|SA_CORE, /* SIGILL */ 93 SA_KILL|SA_CORE, /* SIGTRAP */ 94 SA_KILL|SA_CORE, /* SIGABRT */ 95 SA_KILL|SA_CORE, /* SIGEMT */ 96 SA_KILL|SA_CORE, /* SIGFPE */ 97 SA_KILL, /* SIGKILL */ 98 SA_KILL|SA_CORE, /* SIGBUS */ 99 SA_KILL|SA_CORE, /* SIGSEGV */ 100 SA_KILL|SA_CORE, /* SIGSYS */ 101 SA_KILL, /* SIGPIPE */ 102 SA_KILL, /* SIGALRM */ 103 SA_KILL, /* SIGTERM */ 104 SA_IGNORE, /* SIGURG */ 105 SA_STOP, /* SIGSTOP */ 106 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 107 SA_IGNORE|SA_CONT, /* SIGCONT */ 108 SA_IGNORE, /* SIGCHLD */ 109 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 110 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 111 SA_IGNORE, /* SIGIO */ 112 SA_KILL, /* SIGXCPU */ 113 SA_KILL, /* SIGXFSZ */ 114 SA_KILL, /* SIGVTALRM */ 115 SA_KILL, /* SIGPROF */ 116 SA_IGNORE, /* SIGWINCH */ 117 SA_IGNORE, /* SIGINFO */ 118 SA_KILL, /* SIGUSR1 */ 119 SA_KILL, /* SIGUSR2 */ 120 SA_IGNORE, /* SIGTHR */ 121}; 122 123#define CONTSIGMASK (sigmask(SIGCONT)) 124#define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ 125 sigmask(SIGTTIN) | sigmask(SIGTTOU)) 126 127void setsigvec(struct proc *, int, struct sigaction *); 128 129void proc_stop(struct proc *p, int); 130void proc_stop_sweep(void *); 131void *proc_stop_si; 132 133void setsigctx(struct proc *, int, struct sigctx *); 134void postsig_done(struct proc *, int, sigset_t, int); 135void postsig(struct proc *, int, struct sigctx *); 136int cansignal(struct proc *, struct process *, int); 137 138struct pool sigacts_pool; /* memory pool for sigacts structures */ 139 140void sigio_del(struct sigiolst *); 141void sigio_unlink(struct sigio_ref *, struct sigiolst *); 142struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); 143 144/* 145 * Can thread p, send the signal signum to process qr? 146 */ 147int 148cansignal(struct proc *p, struct process *qr, int signum) 149{ 150 struct process *pr = p->p_p; 151 struct ucred *uc = p->p_ucred; 152 struct ucred *quc = qr->ps_ucred; 153 154 if (uc->cr_uid == 0) 155 return (1); /* root can always signal */ 156 157 if (pr == qr) 158 return (1); /* process can always signal itself */ 159 160 /* optimization: if the same creds then the tests below will pass */ 161 if (uc == quc) 162 return (1); 163 164 if (signum == SIGCONT && qr->ps_session == pr->ps_session) 165 return (1); /* SIGCONT in session */ 166 167 /* 168 * Using kill(), only certain signals can be sent to setugid 169 * child processes 170 */ 171 if (qr->ps_flags & PS_SUGID) { 172 switch (signum) { 173 case 0: 174 case SIGKILL: 175 case SIGINT: 176 case SIGTERM: 177 case SIGALRM: 178 case SIGSTOP: 179 case SIGTTIN: 180 case SIGTTOU: 181 case SIGTSTP: 182 case SIGHUP: 183 case SIGUSR1: 184 case SIGUSR2: 185 if (uc->cr_ruid == quc->cr_ruid || 186 uc->cr_uid == quc->cr_ruid) 187 return (1); 188 } 189 return (0); 190 } 191 192 if (uc->cr_ruid == quc->cr_ruid || 193 uc->cr_ruid == quc->cr_svuid || 194 uc->cr_uid == quc->cr_ruid || 195 uc->cr_uid == quc->cr_svuid) 196 return (1); 197 return (0); 198} 199 200/* 201 * Initialize signal-related data structures. 202 */ 203void 204signal_init(void) 205{ 206 proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, 207 NULL); 208 if (proc_stop_si == NULL) 209 panic("signal_init failed to register softintr"); 210 211 pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, 212 PR_WAITOK, "sigapl", NULL); 213} 214 215/* 216 * Initialize a new sigaltstack structure. 217 */ 218void 219sigstkinit(struct sigaltstack *ss) 220{ 221 ss->ss_flags = SS_DISABLE; 222 ss->ss_size = 0; 223 ss->ss_sp = NULL; 224} 225 226/* 227 * Create an initial sigacts structure, using the same signal state 228 * as pr. 229 */ 230struct sigacts * 231sigactsinit(struct process *pr) 232{ 233 struct sigacts *ps; 234 235 ps = pool_get(&sigacts_pool, PR_WAITOK); 236 memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); 237 return (ps); 238} 239 240/* 241 * Release a sigacts structure. 242 */ 243void 244sigactsfree(struct sigacts *ps) 245{ 246 pool_put(&sigacts_pool, ps); 247} 248 249int 250sys_sigaction(struct proc *p, void *v, register_t *retval) 251{ 252 struct sys_sigaction_args /* { 253 syscallarg(int) signum; 254 syscallarg(const struct sigaction *) nsa; 255 syscallarg(struct sigaction *) osa; 256 } */ *uap = v; 257 struct sigaction vec; 258#ifdef KTRACE 259 struct sigaction ovec; 260#endif 261 struct sigaction *sa; 262 const struct sigaction *nsa; 263 struct sigaction *osa; 264 struct sigacts *ps = p->p_p->ps_sigacts; 265 int signum; 266 int bit, error; 267 268 signum = SCARG(uap, signum); 269 nsa = SCARG(uap, nsa); 270 osa = SCARG(uap, osa); 271 272 if (signum <= 0 || signum >= NSIG || 273 (nsa && (signum == SIGKILL || signum == SIGSTOP))) 274 return (EINVAL); 275 sa = &vec; 276 if (osa) { 277 mtx_enter(&p->p_p->ps_mtx); 278 sa->sa_handler = ps->ps_sigact[signum]; 279 sa->sa_mask = ps->ps_catchmask[signum]; 280 bit = sigmask(signum); 281 sa->sa_flags = 0; 282 if ((ps->ps_sigonstack & bit) != 0) 283 sa->sa_flags |= SA_ONSTACK; 284 if ((ps->ps_sigintr & bit) == 0) 285 sa->sa_flags |= SA_RESTART; 286 if ((ps->ps_sigreset & bit) != 0) 287 sa->sa_flags |= SA_RESETHAND; 288 if ((ps->ps_siginfo & bit) != 0) 289 sa->sa_flags |= SA_SIGINFO; 290 if (signum == SIGCHLD) { 291 if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) 292 sa->sa_flags |= SA_NOCLDSTOP; 293 if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) 294 sa->sa_flags |= SA_NOCLDWAIT; 295 } 296 mtx_leave(&p->p_p->ps_mtx); 297 if ((sa->sa_mask & bit) == 0) 298 sa->sa_flags |= SA_NODEFER; 299 sa->sa_mask &= ~bit; 300 error = copyout(sa, osa, sizeof (vec)); 301 if (error) 302 return (error); 303#ifdef KTRACE 304 if (KTRPOINT(p, KTR_STRUCT)) 305 ovec = vec; 306#endif 307 } 308 if (nsa) { 309 error = copyin(nsa, sa, sizeof (vec)); 310 if (error) 311 return (error); 312#ifdef KTRACE 313 if (KTRPOINT(p, KTR_STRUCT)) 314 ktrsigaction(p, sa); 315#endif 316 setsigvec(p, signum, sa); 317 } 318#ifdef KTRACE 319 if (osa && KTRPOINT(p, KTR_STRUCT)) 320 ktrsigaction(p, &ovec); 321#endif 322 return (0); 323} 324 325void 326setsigvec(struct proc *p, int signum, struct sigaction *sa) 327{ 328 struct sigacts *ps = p->p_p->ps_sigacts; 329 int bit; 330 331 bit = sigmask(signum); 332 333 mtx_enter(&p->p_p->ps_mtx); 334 ps->ps_sigact[signum] = sa->sa_handler; 335 if ((sa->sa_flags & SA_NODEFER) == 0) 336 sa->sa_mask |= sigmask(signum); 337 ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; 338 if (signum == SIGCHLD) { 339 if (sa->sa_flags & SA_NOCLDSTOP) 340 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 341 else 342 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); 343 /* 344 * If the SA_NOCLDWAIT flag is set or the handler 345 * is SIG_IGN we reparent the dying child to PID 1 346 * (init) which will reap the zombie. Because we use 347 * init to do our dirty work we never set SAS_NOCLDWAIT 348 * for PID 1. 349 * XXX exit1 rework means this is unnecessary? 350 */ 351 if (initprocess->ps_sigacts != ps && 352 ((sa->sa_flags & SA_NOCLDWAIT) || 353 sa->sa_handler == SIG_IGN)) 354 atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 355 else 356 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 357 } 358 if ((sa->sa_flags & SA_RESETHAND) != 0) 359 ps->ps_sigreset |= bit; 360 else 361 ps->ps_sigreset &= ~bit; 362 if ((sa->sa_flags & SA_SIGINFO) != 0) 363 ps->ps_siginfo |= bit; 364 else 365 ps->ps_siginfo &= ~bit; 366 if ((sa->sa_flags & SA_RESTART) == 0) 367 ps->ps_sigintr |= bit; 368 else 369 ps->ps_sigintr &= ~bit; 370 if ((sa->sa_flags & SA_ONSTACK) != 0) 371 ps->ps_sigonstack |= bit; 372 else 373 ps->ps_sigonstack &= ~bit; 374 /* 375 * Set bit in ps_sigignore for signals that are set to SIG_IGN, 376 * and for signals set to SIG_DFL where the default is to ignore. 377 * However, don't put SIGCONT in ps_sigignore, 378 * as we have to restart the process. 379 */ 380 if (sa->sa_handler == SIG_IGN || 381 (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { 382 atomic_clearbits_int(&p->p_siglist, bit); 383 atomic_clearbits_int(&p->p_p->ps_siglist, bit); 384 if (signum != SIGCONT) 385 ps->ps_sigignore |= bit; /* easier in psignal */ 386 ps->ps_sigcatch &= ~bit; 387 } else { 388 ps->ps_sigignore &= ~bit; 389 if (sa->sa_handler == SIG_DFL) 390 ps->ps_sigcatch &= ~bit; 391 else 392 ps->ps_sigcatch |= bit; 393 } 394 mtx_leave(&p->p_p->ps_mtx); 395} 396 397/* 398 * Initialize signal state for process 0; 399 * set to ignore signals that are ignored by default. 400 */ 401void 402siginit(struct sigacts *ps) 403{ 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 */ 415void 416execsigs(struct proc *p) 417{ 418 struct sigacts *ps; 419 int nc, mask; 420 421 ps = p->p_p->ps_sigacts; 422 mtx_enter(&p->p_p->ps_mtx); 423 424 /* 425 * Reset caught signals. Held signals remain held 426 * through p_sigmask (unless they were caught, 427 * and are now ignored by default). 428 */ 429 while (ps->ps_sigcatch) { 430 nc = ffs((long)ps->ps_sigcatch); 431 mask = sigmask(nc); 432 ps->ps_sigcatch &= ~mask; 433 if (sigprop[nc] & SA_IGNORE) { 434 if (nc != SIGCONT) 435 ps->ps_sigignore |= mask; 436 atomic_clearbits_int(&p->p_siglist, mask); 437 atomic_clearbits_int(&p->p_p->ps_siglist, mask); 438 } 439 ps->ps_sigact[nc] = SIG_DFL; 440 } 441 /* 442 * Reset stack state to the user stack. 443 * Clear set of signals caught on the signal stack. 444 */ 445 sigstkinit(&p->p_sigstk); 446 atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); 447 if (ps->ps_sigact[SIGCHLD] == SIG_IGN) 448 ps->ps_sigact[SIGCHLD] = SIG_DFL; 449 mtx_leave(&p->p_p->ps_mtx); 450} 451 452/* 453 * Manipulate signal mask. 454 * Note that we receive new mask, not pointer, 455 * and return old mask as return value; 456 * the library stub does the rest. 457 */ 458int 459sys_sigprocmask(struct proc *p, void *v, register_t *retval) 460{ 461 struct sys_sigprocmask_args /* { 462 syscallarg(int) how; 463 syscallarg(sigset_t) mask; 464 } */ *uap = v; 465 int error = 0; 466 sigset_t mask; 467 468 KASSERT(p == curproc); 469 470 *retval = p->p_sigmask; 471 mask = SCARG(uap, mask) &~ sigcantmask; 472 473 switch (SCARG(uap, how)) { 474 case SIG_BLOCK: 475 SET(p->p_sigmask, mask); 476 break; 477 case SIG_UNBLOCK: 478 CLR(p->p_sigmask, mask); 479 break; 480 case SIG_SETMASK: 481 p->p_sigmask = mask; 482 break; 483 default: 484 error = EINVAL; 485 break; 486 } 487 return (error); 488} 489 490int 491sys_sigpending(struct proc *p, void *v, register_t *retval) 492{ 493 *retval = p->p_siglist | p->p_p->ps_siglist; 494 return (0); 495} 496 497/* 498 * Temporarily replace calling proc's signal mask for the duration of a 499 * system call. Original signal mask will be restored by userret(). 500 */ 501void 502dosigsuspend(struct proc *p, sigset_t newmask) 503{ 504 KASSERT(p == curproc); 505 506 p->p_oldmask = p->p_sigmask; 507 p->p_sigmask = newmask; 508 atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); 509} 510 511/* 512 * Suspend thread until signal, providing mask to be set 513 * in the meantime. Note nonstandard calling convention: 514 * libc stub passes mask, not pointer, to save a copyin. 515 */ 516int 517sys_sigsuspend(struct proc *p, void *v, register_t *retval) 518{ 519 struct sys_sigsuspend_args /* { 520 syscallarg(int) mask; 521 } */ *uap = v; 522 523 dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); 524 while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) 525 continue; 526 /* always return EINTR rather than ERESTART... */ 527 return (EINTR); 528} 529 530int 531sigonstack(size_t stack) 532{ 533 const struct sigaltstack *ss = &curproc->p_sigstk; 534 535 return (ss->ss_flags & SS_DISABLE ? 0 : 536 (stack - (size_t)ss->ss_sp < ss->ss_size)); 537} 538 539int 540sys_sigaltstack(struct proc *p, void *v, register_t *retval) 541{ 542 struct sys_sigaltstack_args /* { 543 syscallarg(const struct sigaltstack *) nss; 544 syscallarg(struct sigaltstack *) oss; 545 } */ *uap = v; 546 struct sigaltstack ss; 547 const struct sigaltstack *nss; 548 struct sigaltstack *oss; 549 int onstack = sigonstack(PROC_STACK(p)); 550 int error; 551 552 nss = SCARG(uap, nss); 553 oss = SCARG(uap, oss); 554 555 if (oss != NULL) { 556 ss = p->p_sigstk; 557 if (onstack) 558 ss.ss_flags |= SS_ONSTACK; 559 if ((error = copyout(&ss, oss, sizeof(ss)))) 560 return (error); 561 } 562 if (nss == NULL) 563 return (0); 564 error = copyin(nss, &ss, sizeof(ss)); 565 if (error) 566 return (error); 567 if (onstack) 568 return (EPERM); 569 if (ss.ss_flags & ~SS_DISABLE) 570 return (EINVAL); 571 if (ss.ss_flags & SS_DISABLE) { 572 p->p_sigstk.ss_flags = ss.ss_flags; 573 return (0); 574 } 575 if (ss.ss_size < MINSIGSTKSZ) 576 return (ENOMEM); 577 578 error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); 579 if (error) 580 return (error); 581 582 p->p_sigstk = ss; 583 return (0); 584} 585 586int 587sys_kill(struct proc *cp, void *v, register_t *retval) 588{ 589 struct sys_kill_args /* { 590 syscallarg(int) pid; 591 syscallarg(int) signum; 592 } */ *uap = v; 593 struct process *pr; 594 int pid = SCARG(uap, pid); 595 int signum = SCARG(uap, signum); 596 int error; 597 int zombie = 0; 598 599 if ((error = pledge_kill(cp, pid)) != 0) 600 return (error); 601 if (((u_int)signum) >= NSIG) 602 return (EINVAL); 603 if (pid > 0) { 604 if ((pr = prfind(pid)) == NULL) { 605 if ((pr = zombiefind(pid)) == NULL) 606 return (ESRCH); 607 else 608 zombie = 1; 609 } 610 if (!cansignal(cp, pr, signum)) 611 return (EPERM); 612 613 /* kill single process */ 614 if (signum && !zombie) 615 prsignal(pr, signum); 616 return (0); 617 } 618 switch (pid) { 619 case -1: /* broadcast signal */ 620 return (killpg1(cp, signum, 0, 1)); 621 case 0: /* signal own process group */ 622 return (killpg1(cp, signum, 0, 0)); 623 default: /* negative explicit process group */ 624 return (killpg1(cp, signum, -pid, 0)); 625 } 626} 627 628int 629sys_thrkill(struct proc *cp, void *v, register_t *retval) 630{ 631 struct sys_thrkill_args /* { 632 syscallarg(pid_t) tid; 633 syscallarg(int) signum; 634 syscallarg(void *) tcb; 635 } */ *uap = v; 636 struct proc *p; 637 int tid = SCARG(uap, tid); 638 int signum = SCARG(uap, signum); 639 void *tcb; 640 641 if (((u_int)signum) >= NSIG) 642 return (EINVAL); 643 644 p = tid ? tfind_user(tid, cp->p_p) : cp; 645 if (p == NULL) 646 return (ESRCH); 647 648 /* optionally require the target thread to have the given tcb addr */ 649 tcb = SCARG(uap, tcb); 650 if (tcb != NULL && tcb != TCB_GET(p)) 651 return (ESRCH); 652 653 if (signum) 654 ptsignal(p, signum, STHREAD); 655 return (0); 656} 657 658/* 659 * Common code for kill process group/broadcast kill. 660 * cp is calling process. 661 */ 662int 663killpg1(struct proc *cp, int signum, int pgid, int all) 664{ 665 struct process *pr; 666 struct pgrp *pgrp; 667 int nfound = 0; 668 669 if (all) { 670 /* 671 * broadcast 672 */ 673 LIST_FOREACH(pr, &allprocess, ps_list) { 674 if (pr->ps_pid <= 1 || 675 pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || 676 pr == cp->p_p || !cansignal(cp, pr, signum)) 677 continue; 678 nfound++; 679 if (signum) 680 prsignal(pr, signum); 681 } 682 } else { 683 if (pgid == 0) 684 /* 685 * zero pgid means send to my process group. 686 */ 687 pgrp = cp->p_p->ps_pgrp; 688 else { 689 pgrp = pgfind(pgid); 690 if (pgrp == NULL) 691 return (ESRCH); 692 } 693 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { 694 if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || 695 !cansignal(cp, pr, signum)) 696 continue; 697 nfound++; 698 if (signum) 699 prsignal(pr, signum); 700 } 701 } 702 return (nfound ? 0 : ESRCH); 703} 704 705#define CANDELIVER(uid, euid, pr) \ 706 (euid == 0 || \ 707 (uid) == (pr)->ps_ucred->cr_ruid || \ 708 (uid) == (pr)->ps_ucred->cr_svuid || \ 709 (uid) == (pr)->ps_ucred->cr_uid || \ 710 (euid) == (pr)->ps_ucred->cr_ruid || \ 711 (euid) == (pr)->ps_ucred->cr_svuid || \ 712 (euid) == (pr)->ps_ucred->cr_uid) 713 714#define CANSIGIO(cr, pr) \ 715 CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) 716 717/* 718 * Send a signal to a process group. If checktty is 1, 719 * limit to members which have a controlling terminal. 720 */ 721void 722pgsignal(struct pgrp *pgrp, int signum, int checkctty) 723{ 724 struct process *pr; 725 726 if (pgrp) 727 LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) 728 if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) 729 prsignal(pr, signum); 730} 731 732/* 733 * Send a SIGIO or SIGURG signal to a process or process group using stored 734 * credentials rather than those of the current process. 735 */ 736void 737pgsigio(struct sigio_ref *sir, int sig, int checkctty) 738{ 739 struct process *pr; 740 struct sigio *sigio; 741 742 if (sir->sir_sigio == NULL) 743 return; 744 745 KERNEL_LOCK(); 746 mtx_enter(&sigio_lock); 747 sigio = sir->sir_sigio; 748 if (sigio == NULL) 749 goto out; 750 if (sigio->sio_pgid > 0) { 751 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) 752 prsignal(sigio->sio_proc, sig); 753 } else if (sigio->sio_pgid < 0) { 754 LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { 755 if (CANSIGIO(sigio->sio_ucred, pr) && 756 (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) 757 prsignal(pr, sig); 758 } 759 } 760out: 761 mtx_leave(&sigio_lock); 762 KERNEL_UNLOCK(); 763} 764 765/* 766 * Recalculate the signal mask and reset the signal disposition after 767 * usermode frame for delivery is formed. 768 */ 769void 770postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) 771{ 772 p->p_ru.ru_nsignals++; 773 SET(p->p_sigmask, catchmask); 774 if (reset != 0) { 775 sigset_t mask = sigmask(signum); 776 struct sigacts *ps = p->p_p->ps_sigacts; 777 778 mtx_enter(&p->p_p->ps_mtx); 779 ps->ps_sigcatch &= ~mask; 780 if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) 781 ps->ps_sigignore |= mask; 782 ps->ps_sigact[signum] = SIG_DFL; 783 mtx_leave(&p->p_p->ps_mtx); 784 } 785} 786 787/* 788 * Send a signal caused by a trap to the current thread 789 * If it will be caught immediately, deliver it with correct code. 790 * Otherwise, post it normally. 791 */ 792void 793trapsignal(struct proc *p, int signum, u_long trapno, int code, 794 union sigval sigval) 795{ 796 struct process *pr = p->p_p; 797 struct sigctx ctx; 798 int mask; 799 800 switch (signum) { 801 case SIGILL: 802 if (code == ILL_BTCFI) { 803 pr->ps_acflag |= ABTCFI; 804 break; 805 } 806 /* FALLTHROUGH */ 807 case SIGBUS: 808 case SIGSEGV: 809 pr->ps_acflag |= ATRAP; 810 break; 811 } 812 813 mask = sigmask(signum); 814 setsigctx(p, signum, &ctx); 815 if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && 816 (p->p_sigmask & mask) == 0) { 817 siginfo_t si; 818 819 initsiginfo(&si, signum, trapno, code, sigval); 820#ifdef KTRACE 821 if (KTRPOINT(p, KTR_PSIG)) { 822 ktrpsig(p, signum, ctx.sig_action, 823 p->p_sigmask, code, &si); 824 } 825#endif 826 if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, 827 ctx.sig_info, ctx.sig_onstack)) { 828 KERNEL_LOCK(); 829 sigexit(p, SIGILL); 830 /* NOTREACHED */ 831 } 832 postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); 833 } else { 834 p->p_sisig = signum; 835 p->p_sitrapno = trapno; /* XXX for core dump/debugger */ 836 p->p_sicode = code; 837 p->p_sigval = sigval; 838 839 /* 840 * If traced, stop if signal is masked, and stay stopped 841 * until released by the debugger. If our parent process 842 * is waiting for us, don't hang as we could deadlock. 843 */ 844 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 845 signum != SIGKILL && (p->p_sigmask & mask) != 0) { 846 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 847 pr->ps_xsig = signum; 848 849 SCHED_LOCK(); 850 proc_stop(p, 1); 851 SCHED_UNLOCK(); 852 853 signum = pr->ps_xsig; 854 single_thread_clear(p, 0); 855 856 /* 857 * If we are no longer being traced, or the parent 858 * didn't give us a signal, skip sending the signal. 859 */ 860 if ((pr->ps_flags & PS_TRACED) == 0 || 861 signum == 0) 862 return; 863 864 /* update signal info */ 865 p->p_sisig = signum; 866 mask = sigmask(signum); 867 } 868 869 /* 870 * Signals like SIGBUS and SIGSEGV should not, when 871 * generated by the kernel, be ignorable or blockable. 872 * If it is and we're not being traced, then just kill 873 * the process. 874 * After vfs_shutdown(9), init(8) cannot receive signals 875 * because new code pages of the signal handler cannot be 876 * mapped from halted storage. init(8) may not die or the 877 * kernel panics. Better loop between signal handler and 878 * page fault trap until the machine is halted. 879 */ 880 if ((pr->ps_flags & PS_TRACED) == 0 && 881 (sigprop[signum] & SA_KILL) && 882 ((p->p_sigmask & mask) || ctx.sig_ignore) && 883 pr->ps_pid != 1) { 884 KERNEL_LOCK(); 885 sigexit(p, signum); 886 /* NOTREACHED */ 887 } 888 KERNEL_LOCK(); 889 ptsignal(p, signum, STHREAD); 890 KERNEL_UNLOCK(); 891 } 892} 893 894/* 895 * Send the signal to the process. If the signal has an action, the action 896 * is usually performed by the target process rather than the caller; we add 897 * the signal to the set of pending signals for the process. 898 * 899 * Exceptions: 900 * o When a stop signal is sent to a sleeping process that takes the 901 * default action, the process is stopped without awakening it. 902 * o SIGCONT restarts stopped processes (or puts them back to sleep) 903 * regardless of the signal action (eg, blocked or ignored). 904 * 905 * Other ignored signals are discarded immediately. 906 */ 907void 908psignal(struct proc *p, int signum) 909{ 910 ptsignal(p, signum, SPROCESS); 911} 912 913/* 914 * type = SPROCESS process signal, can be diverted (sigwait()) 915 * type = STHREAD thread signal, but should be propagated if unhandled 916 * type = SPROPAGATED propagated to this thread, so don't propagate again 917 */ 918void 919ptsignal(struct proc *p, int signum, enum signal_type type) 920{ 921 int prop; 922 sig_t action, altaction = SIG_DFL; 923 sigset_t mask, sigmask; 924 int *siglist; 925 struct process *pr = p->p_p; 926 struct proc *q; 927 int wakeparent = 0; 928 929 KERNEL_ASSERT_LOCKED(); 930 931#ifdef DIAGNOSTIC 932 if ((u_int)signum >= NSIG || signum == 0) 933 panic("psignal signal number"); 934#endif 935 936 /* Ignore signal if the target process is exiting */ 937 if (pr->ps_flags & PS_EXITING) 938 return; 939 940 mask = sigmask(signum); 941 sigmask = READ_ONCE(p->p_sigmask); 942 943 if (type == SPROCESS) { 944 sigset_t tmpmask; 945 946 /* Accept SIGKILL to coredumping processes */ 947 if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { 948 atomic_setbits_int(&pr->ps_siglist, mask); 949 return; 950 } 951 952 /* 953 * If the current thread can process the signal 954 * immediately (it's unblocked) then have it take it. 955 */ 956 q = curproc; 957 tmpmask = READ_ONCE(q->p_sigmask); 958 if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && 959 (tmpmask & mask) == 0) { 960 p = q; 961 sigmask = tmpmask; 962 } else { 963 /* 964 * A process-wide signal can be diverted to a 965 * different thread that's in sigwait() for this 966 * signal. If there isn't such a thread, then 967 * pick a thread that doesn't have it blocked so 968 * that the stop/kill consideration isn't 969 * delayed. Otherwise, mark it pending on the 970 * main thread. 971 */ 972 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 973 974 /* ignore exiting threads */ 975 if (q->p_flag & P_WEXIT) 976 continue; 977 978 /* skip threads that have the signal blocked */ 979 tmpmask = READ_ONCE(q->p_sigmask); 980 if ((tmpmask & mask) != 0) 981 continue; 982 983 /* okay, could send to this thread */ 984 p = q; 985 sigmask = tmpmask; 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_locked(&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 (sigmask & mask) { 1026 action = SIG_HOLD; 1027 if (sigcatch & mask) 1028 altaction = SIG_CATCH; 1029 } else if (sigcatch & mask) { 1030 action = SIG_CATCH; 1031 } else { 1032 action = SIG_DFL; 1033 1034 if (prop & SA_KILL && pr->ps_nice > NZERO) 1035 pr->ps_nice = NZERO; 1036 1037 /* 1038 * If sending a tty stop signal to a member of an 1039 * orphaned process group, discard the signal here if 1040 * the action is default; don't stop the process below 1041 * if sleeping, and don't clear any pending SIGCONT. 1042 */ 1043 if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) 1044 return; 1045 } 1046 } 1047 /* 1048 * If delivered to process, mark as pending there. Continue and stop 1049 * signals will be propagated to all threads. So they are always 1050 * marked at thread level. 1051 */ 1052 siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; 1053 if (prop & (SA_CONT | SA_STOP)) 1054 siglist = &p->p_siglist; 1055 1056 /* 1057 * XXX delay processing of SA_STOP signals unless action == SIG_DFL? 1058 */ 1059 if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) 1060 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) 1061 if (q != p) 1062 ptsignal(q, signum, SPROPAGATED); 1063 1064 SCHED_LOCK(); 1065 1066 switch (p->p_stat) { 1067 1068 case SSLEEP: 1069 /* 1070 * If process is sleeping uninterruptibly 1071 * we can't interrupt the sleep... the signal will 1072 * be noticed when the process returns through 1073 * trap() or syscall(). 1074 */ 1075 if ((p->p_flag & P_SINTR) == 0) 1076 goto out; 1077 /* 1078 * Process is sleeping and traced... make it runnable 1079 * so it can discover the signal in cursig() and stop 1080 * for the parent. 1081 */ 1082 if (pr->ps_flags & PS_TRACED) 1083 goto run; 1084 1085 /* 1086 * Recheck sigmask before waking up the process, 1087 * there is a chance that while sending the signal 1088 * the process changed sigmask and went to sleep. 1089 */ 1090 sigmask = READ_ONCE(p->p_sigmask); 1091 if (sigmask & mask) 1092 goto out; 1093 else if (action == SIG_HOLD) { 1094 /* signal got unmasked, get proper action */ 1095 action = altaction; 1096 1097 if (action == SIG_DFL) { 1098 if (prop & SA_KILL && pr->ps_nice > NZERO) 1099 pr->ps_nice = NZERO; 1100 1101 /* 1102 * Discard tty stop signals sent to an 1103 * orphaned process group, see above. 1104 */ 1105 if (prop & SA_TTYSTOP && 1106 pr->ps_pgrp->pg_jobc == 0) { 1107 mask = 0; 1108 prop = 0; 1109 goto out; 1110 } 1111 } 1112 } 1113 1114 /* 1115 * If SIGCONT is default (or ignored) and process is 1116 * asleep, we are finished; the process should not 1117 * be awakened. 1118 */ 1119 if ((prop & SA_CONT) && action == SIG_DFL) { 1120 mask = 0; 1121 goto out; 1122 } 1123 /* 1124 * When a sleeping process receives a stop 1125 * signal, process immediately if possible. 1126 */ 1127 if ((prop & SA_STOP) && action == SIG_DFL) { 1128 /* 1129 * If a child holding parent blocked, 1130 * stopping could cause deadlock. 1131 */ 1132 if (pr->ps_flags & PS_PPWAIT) 1133 goto out; 1134 mask = 0; 1135 pr->ps_xsig = signum; 1136 proc_stop(p, 0); 1137 goto out; 1138 } 1139 /* 1140 * All other (caught or default) signals 1141 * cause the process to run. 1142 */ 1143 goto runfast; 1144 /* NOTREACHED */ 1145 1146 case SSTOP: 1147 /* 1148 * If traced process is already stopped, 1149 * then no further action is necessary. 1150 */ 1151 if (pr->ps_flags & PS_TRACED) 1152 goto out; 1153 1154 /* 1155 * Kill signal always sets processes running. 1156 */ 1157 if (signum == SIGKILL) { 1158 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1159 goto runfast; 1160 } 1161 1162 if (prop & SA_CONT) { 1163 /* 1164 * If SIGCONT is default (or ignored), we continue the 1165 * process but don't leave the signal in p_siglist, as 1166 * it has no further action. If SIGCONT is held, we 1167 * continue the process and leave the signal in 1168 * p_siglist. If the process catches SIGCONT, let it 1169 * handle the signal itself. If it isn't waiting on 1170 * an event, then it goes back to run state. 1171 * Otherwise, process goes back to sleep state. 1172 */ 1173 atomic_setbits_int(&p->p_flag, P_CONTINUED); 1174 atomic_clearbits_int(&p->p_flag, P_SUSPSIG); 1175 wakeparent = 1; 1176 if (action == SIG_DFL) 1177 mask = 0; 1178 if (action == SIG_CATCH) 1179 goto runfast; 1180 if (p->p_wchan == NULL) 1181 goto run; 1182 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 1183 p->p_stat = SSLEEP; 1184 goto out; 1185 } 1186 1187 /* 1188 * Defer further processing for signals which are held, 1189 * except that stopped processes must be continued by SIGCONT. 1190 */ 1191 if (action == SIG_HOLD) 1192 goto out; 1193 1194 if (prop & SA_STOP) { 1195 /* 1196 * Already stopped, don't need to stop again. 1197 * (If we did the shell could get confused.) 1198 */ 1199 mask = 0; 1200 goto out; 1201 } 1202 1203 /* 1204 * If process is sleeping interruptibly, then simulate a 1205 * wakeup so that when it is continued, it will be made 1206 * runnable and can look at the signal. But don't make 1207 * the process runnable, leave it stopped. 1208 */ 1209 if (p->p_flag & P_SINTR) 1210 unsleep(p); 1211 goto out; 1212 1213 case SONPROC: 1214 if (action == SIG_HOLD) 1215 goto out; 1216 1217 /* set siglist before issuing the ast */ 1218 atomic_setbits_int(siglist, mask); 1219 mask = 0; 1220 signotify(p); 1221 /* FALLTHROUGH */ 1222 default: 1223 /* 1224 * SRUN, SIDL, SDEAD do nothing with the signal, 1225 * other than kicking ourselves if we are running. 1226 * It will either never be noticed, or noticed very soon. 1227 */ 1228 goto out; 1229 } 1230 /* NOTREACHED */ 1231 1232runfast: 1233 /* 1234 * Raise priority to at least PUSER. 1235 */ 1236 if (p->p_usrpri > PUSER) 1237 p->p_usrpri = PUSER; 1238run: 1239 unsleep(p); 1240 setrunnable(p); 1241out: 1242 /* finally adjust siglist */ 1243 if (mask) 1244 atomic_setbits_int(siglist, mask); 1245 if (prop & SA_CONT) { 1246 atomic_clearbits_int(siglist, STOPSIGMASK); 1247 } 1248 if (prop & SA_STOP) { 1249 atomic_clearbits_int(siglist, CONTSIGMASK); 1250 atomic_clearbits_int(&p->p_flag, P_CONTINUED); 1251 } 1252 1253 SCHED_UNLOCK(); 1254 if (wakeparent) 1255 wakeup(pr->ps_pptr); 1256} 1257 1258/* fill the signal context which should be used by postsig() and issignal() */ 1259void 1260setsigctx(struct proc *p, int signum, struct sigctx *sctx) 1261{ 1262 struct sigacts *ps = p->p_p->ps_sigacts; 1263 sigset_t mask; 1264 1265 mtx_enter(&p->p_p->ps_mtx); 1266 mask = sigmask(signum); 1267 sctx->sig_action = ps->ps_sigact[signum]; 1268 sctx->sig_catchmask = ps->ps_catchmask[signum]; 1269 sctx->sig_reset = (ps->ps_sigreset & mask) != 0; 1270 sctx->sig_info = (ps->ps_siginfo & mask) != 0; 1271 sctx->sig_intr = (ps->ps_sigintr & mask) != 0; 1272 sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; 1273 sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; 1274 sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; 1275 mtx_leave(&p->p_p->ps_mtx); 1276} 1277 1278/* 1279 * Determine signal that should be delivered to process p, the current 1280 * process, 0 if none. 1281 * 1282 * If the current process has received a signal (should be caught or cause 1283 * termination, should interrupt current syscall), return the signal number. 1284 * Stop signals with default action are processed immediately, then cleared; 1285 * they aren't returned. This is checked after each entry to the system for 1286 * a syscall or trap. The normal call sequence is 1287 * 1288 * while (signum = cursig(curproc, &ctx)) 1289 * postsig(signum, &ctx); 1290 * 1291 * Assumes that if the P_SINTR flag is set, we're holding both the 1292 * kernel and scheduler locks. 1293 */ 1294int 1295cursig(struct proc *p, struct sigctx *sctx) 1296{ 1297 struct process *pr = p->p_p; 1298 int signum, mask, prop; 1299 sigset_t ps_siglist; 1300 1301 KASSERT(p == curproc); 1302 1303 for (;;) { 1304 ps_siglist = READ_ONCE(pr->ps_siglist); 1305 membar_consumer(); 1306 mask = SIGPENDING(p); 1307 if (pr->ps_flags & PS_PPWAIT) 1308 mask &= ~STOPSIGMASK; 1309 if (mask == 0) /* no signal to send */ 1310 return (0); 1311 signum = ffs((long)mask); 1312 mask = sigmask(signum); 1313 1314 /* take the signal! */ 1315 if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, 1316 ps_siglist & ~mask) != ps_siglist) { 1317 /* lost race taking the process signal, restart */ 1318 continue; 1319 } 1320 atomic_clearbits_int(&p->p_siglist, mask); 1321 setsigctx(p, signum, sctx); 1322 1323 /* 1324 * We should see pending but ignored signals 1325 * only if PS_TRACED was on when they were posted. 1326 */ 1327 if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) 1328 continue; 1329 1330 /* 1331 * If traced, always stop, and stay stopped until released 1332 * by the debugger. If our parent process is waiting for 1333 * us, don't hang as we could deadlock. 1334 */ 1335 if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && 1336 signum != SIGKILL) { 1337 single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); 1338 pr->ps_xsig = signum; 1339 1340 SCHED_LOCK(); 1341 proc_stop(p, 1); 1342 SCHED_UNLOCK(); 1343 1344 /* 1345 * re-take the signal before releasing 1346 * the other threads. Must check the continue 1347 * conditions below and only take the signal if 1348 * those are not true. 1349 */ 1350 signum = pr->ps_xsig; 1351 mask = sigmask(signum); 1352 setsigctx(p, signum, sctx); 1353 if (!((pr->ps_flags & PS_TRACED) == 0 || 1354 signum == 0 || 1355 (p->p_sigmask & mask) != 0)) { 1356 atomic_clearbits_int(&p->p_siglist, mask); 1357 atomic_clearbits_int(&pr->ps_siglist, mask); 1358 } 1359 1360 single_thread_clear(p, 0); 1361 1362 /* 1363 * If we are no longer being traced, or the parent 1364 * didn't give us a signal, look for more signals. 1365 */ 1366 if ((pr->ps_flags & PS_TRACED) == 0 || 1367 signum == 0) 1368 continue; 1369 1370 /* 1371 * If the new signal is being masked, look for other 1372 * signals. 1373 */ 1374 if ((p->p_sigmask & mask) != 0) 1375 continue; 1376 1377 } 1378 1379 prop = sigprop[signum]; 1380 1381 /* 1382 * Decide whether the signal should be returned. 1383 * Return the signal's number, or fall through 1384 * to clear it from the pending mask. 1385 */ 1386 switch ((long)sctx->sig_action) { 1387 case (long)SIG_DFL: 1388 /* 1389 * Don't take default actions on system processes. 1390 */ 1391 if (pr->ps_pid <= 1) { 1392#ifdef DIAGNOSTIC 1393 /* 1394 * Are you sure you want to ignore SIGSEGV 1395 * in init? XXX 1396 */ 1397 printf("Process (pid %d) got signal" 1398 " %d\n", pr->ps_pid, signum); 1399#endif 1400 break; /* == ignore */ 1401 } 1402 /* 1403 * If there is a pending stop signal to process 1404 * with default action, stop here, 1405 * then clear the signal. However, 1406 * if process is member of an orphaned 1407 * process group, ignore tty stop signals. 1408 */ 1409 if (prop & SA_STOP) { 1410 if (pr->ps_flags & PS_TRACED || 1411 (pr->ps_pgrp->pg_jobc == 0 && 1412 prop & SA_TTYSTOP)) 1413 break; /* == ignore */ 1414 pr->ps_xsig = signum; 1415 SCHED_LOCK(); 1416 proc_stop(p, 1); 1417 SCHED_UNLOCK(); 1418 break; 1419 } else if (prop & SA_IGNORE) { 1420 /* 1421 * Except for SIGCONT, shouldn't get here. 1422 * Default action is to ignore; drop it. 1423 */ 1424 break; /* == ignore */ 1425 } else 1426 goto keep; 1427 /* NOTREACHED */ 1428 case (long)SIG_IGN: 1429 /* 1430 * Masking above should prevent us ever trying 1431 * to take action on an ignored signal other 1432 * than SIGCONT, unless process is traced. 1433 */ 1434 if ((prop & SA_CONT) == 0 && 1435 (pr->ps_flags & PS_TRACED) == 0) 1436 printf("%s\n", __func__); 1437 break; /* == ignore */ 1438 default: 1439 /* 1440 * This signal has an action, let 1441 * postsig() process it. 1442 */ 1443 goto keep; 1444 } 1445 } 1446 /* NOTREACHED */ 1447 1448keep: 1449 atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ 1450 return (signum); 1451} 1452 1453/* 1454 * Put the argument process into the stopped state and notify the parent 1455 * via wakeup. Signals are handled elsewhere. The process must not be 1456 * on the run queue. 1457 */ 1458void 1459proc_stop(struct proc *p, int sw) 1460{ 1461 struct process *pr = p->p_p; 1462 1463#ifdef MULTIPROCESSOR 1464 SCHED_ASSERT_LOCKED(); 1465#endif 1466 /* do not stop exiting procs */ 1467 if (ISSET(p->p_flag, P_WEXIT)) 1468 return; 1469 1470 p->p_stat = SSTOP; 1471 atomic_clearbits_int(&pr->ps_flags, PS_WAITED); 1472 atomic_setbits_int(&pr->ps_flags, PS_STOPPED); 1473 atomic_setbits_int(&p->p_flag, P_SUSPSIG); 1474 /* 1475 * We need this soft interrupt to be handled fast. 1476 * Extra calls to softclock don't hurt. 1477 */ 1478 softintr_schedule(proc_stop_si); 1479 if (sw) 1480 mi_switch(); 1481} 1482 1483/* 1484 * Called from a soft interrupt to send signals to the parents of stopped 1485 * processes. 1486 * We can't do this in proc_stop because it's called with nasty locks held 1487 * and we would need recursive scheduler lock to deal with that. 1488 */ 1489void 1490proc_stop_sweep(void *v) 1491{ 1492 struct process *pr; 1493 1494 LIST_FOREACH(pr, &allprocess, ps_list) { 1495 if ((pr->ps_flags & PS_STOPPED) == 0) 1496 continue; 1497 atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); 1498 1499 if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) 1500 prsignal(pr->ps_pptr, SIGCHLD); 1501 wakeup(pr->ps_pptr); 1502 } 1503} 1504 1505/* 1506 * Take the action for the specified signal 1507 * from the current set of pending signals. 1508 */ 1509void 1510postsig(struct proc *p, int signum, struct sigctx *sctx) 1511{ 1512 u_long trapno; 1513 int mask, returnmask; 1514 siginfo_t si; 1515 union sigval sigval; 1516 int code; 1517 1518 KASSERT(signum != 0); 1519 1520 mask = sigmask(signum); 1521 atomic_clearbits_int(&p->p_siglist, mask); 1522 sigval.sival_ptr = NULL; 1523 1524 if (p->p_sisig != signum) { 1525 trapno = 0; 1526 code = SI_USER; 1527 sigval.sival_ptr = NULL; 1528 } else { 1529 trapno = p->p_sitrapno; 1530 code = p->p_sicode; 1531 sigval = p->p_sigval; 1532 } 1533 initsiginfo(&si, signum, trapno, code, sigval); 1534 1535#ifdef KTRACE 1536 if (KTRPOINT(p, KTR_PSIG)) { 1537 ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? 1538 p->p_oldmask : p->p_sigmask, code, &si); 1539 } 1540#endif 1541 if (sctx->sig_action == SIG_DFL) { 1542 /* 1543 * Default action, where the default is to kill 1544 * the process. (Other cases were ignored above.) 1545 */ 1546 KERNEL_LOCK(); 1547 sigexit(p, signum); 1548 /* NOTREACHED */ 1549 } else { 1550 /* 1551 * If we get here, the signal must be caught. 1552 */ 1553#ifdef DIAGNOSTIC 1554 if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) 1555 panic("postsig action"); 1556#endif 1557 /* 1558 * Set the new mask value and also defer further 1559 * occurrences of this signal. 1560 * 1561 * Special case: user has done a sigpause. Here the 1562 * current mask is not of interest, but rather the 1563 * mask from before the sigpause is what we want 1564 * restored after the signal processing is completed. 1565 */ 1566 if (p->p_flag & P_SIGSUSPEND) { 1567 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 1568 returnmask = p->p_oldmask; 1569 } else { 1570 returnmask = p->p_sigmask; 1571 } 1572 if (p->p_sisig == signum) { 1573 p->p_sisig = 0; 1574 p->p_sitrapno = 0; 1575 p->p_sicode = SI_USER; 1576 p->p_sigval.sival_ptr = NULL; 1577 } 1578 1579 if (sendsig(sctx->sig_action, signum, returnmask, &si, 1580 sctx->sig_info, sctx->sig_onstack)) { 1581 KERNEL_LOCK(); 1582 sigexit(p, SIGILL); 1583 /* NOTREACHED */ 1584 } 1585 postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); 1586 } 1587} 1588 1589/* 1590 * Force the current process to exit with the specified signal, dumping core 1591 * if appropriate. We bypass the normal tests for masked and caught signals, 1592 * allowing unrecoverable failures to terminate the process without changing 1593 * signal state. Mark the accounting record with the signal termination. 1594 * If dumping core, save the signal number for the debugger. Calls exit and 1595 * does not return. 1596 */ 1597void 1598sigexit(struct proc *p, int signum) 1599{ 1600 /* Mark process as going away */ 1601 atomic_setbits_int(&p->p_flag, P_WEXIT); 1602 1603 p->p_p->ps_acflag |= AXSIG; 1604 if (sigprop[signum] & SA_CORE) { 1605 p->p_sisig = signum; 1606 1607 /* if there are other threads, pause them */ 1608 if (P_HASSIBLING(p)) 1609 single_thread_set(p, SINGLE_UNWIND); 1610 1611 if (coredump(p) == 0) 1612 signum |= WCOREFLAG; 1613 } 1614 exit1(p, 0, signum, EXIT_NORMAL); 1615 /* NOTREACHED */ 1616} 1617 1618/* 1619 * Send uncatchable SIGABRT for coredump. 1620 */ 1621void 1622sigabort(struct proc *p) 1623{ 1624 struct sigaction sa; 1625 1626 KASSERT(p == curproc || panicstr || db_active); 1627 1628 memset(&sa, 0, sizeof sa); 1629 sa.sa_handler = SIG_DFL; 1630 setsigvec(p, SIGABRT, &sa); 1631 CLR(p->p_sigmask, sigmask(SIGABRT)); 1632 psignal(p, SIGABRT); 1633} 1634 1635/* 1636 * Return 1 if `sig', a given signal, is ignored or masked for `p', a given 1637 * thread, and 0 otherwise. 1638 */ 1639int 1640sigismasked(struct proc *p, int sig) 1641{ 1642 struct process *pr = p->p_p; 1643 int rv; 1644 1645 KASSERT(p == curproc); 1646 1647 mtx_enter(&pr->ps_mtx); 1648 rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || 1649 (p->p_sigmask & sigmask(sig)); 1650 mtx_leave(&pr->ps_mtx); 1651 1652 return !!rv; 1653} 1654 1655struct coredump_iostate { 1656 struct proc *io_proc; 1657 struct vnode *io_vp; 1658 struct ucred *io_cred; 1659 off_t io_offset; 1660}; 1661 1662/* 1663 * Dump core, into a file named "progname.core", unless the process was 1664 * setuid/setgid. 1665 */ 1666int 1667coredump(struct proc *p) 1668{ 1669#ifdef SMALL_KERNEL 1670 return EPERM; 1671#else 1672 struct process *pr = p->p_p; 1673 struct vnode *vp; 1674 struct ucred *cred = p->p_ucred; 1675 struct vmspace *vm = p->p_vmspace; 1676 struct nameidata nd; 1677 struct vattr vattr; 1678 struct coredump_iostate io; 1679 int error, len, incrash = 0; 1680 char *name; 1681 const char *dir = "/var/crash"; 1682 1683 atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); 1684 1685#ifdef PMAP_CHECK_COPYIN 1686 /* disable copyin checks, so we can write out text sections if needed */ 1687 p->p_vmspace->vm_map.check_copyin_count = 0; 1688#endif 1689 1690 /* Don't dump if will exceed file size limit. */ 1691 if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) 1692 return (EFBIG); 1693 1694 name = pool_get(&namei_pool, PR_WAITOK); 1695 1696 /* 1697 * If the process has inconsistent uids, nosuidcoredump 1698 * determines coredump placement policy. 1699 */ 1700 if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || 1701 ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { 1702 if (nosuidcoredump == 3) { 1703 /* 1704 * If the program directory does not exist, dumps of 1705 * that core will silently fail. 1706 */ 1707 len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", 1708 dir, pr->ps_comm, pr->ps_pid); 1709 incrash = KERNELPATH; 1710 } else if (nosuidcoredump == 2) { 1711 len = snprintf(name, MAXPATHLEN, "%s/%s.core", 1712 dir, pr->ps_comm); 1713 incrash = KERNELPATH; 1714 } else { 1715 pool_put(&namei_pool, name); 1716 return (EPERM); 1717 } 1718 } else 1719 len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); 1720 1721 if (len >= MAXPATHLEN) { 1722 pool_put(&namei_pool, name); 1723 return (EACCES); 1724 } 1725 1726 /* 1727 * Control the UID used to write out. The normal case uses 1728 * the real UID. If the sugid case is going to write into the 1729 * controlled directory, we do so as root. 1730 */ 1731 if (incrash == 0) { 1732 cred = crdup(cred); 1733 cred->cr_uid = cred->cr_ruid; 1734 cred->cr_gid = cred->cr_rgid; 1735 } else { 1736 if (p->p_fd->fd_rdir) { 1737 vrele(p->p_fd->fd_rdir); 1738 p->p_fd->fd_rdir = NULL; 1739 } 1740 p->p_ucred = crdup(p->p_ucred); 1741 crfree(cred); 1742 cred = p->p_ucred; 1743 crhold(cred); 1744 cred->cr_uid = 0; 1745 cred->cr_gid = 0; 1746 } 1747 1748 /* incrash should be 0 or KERNELPATH only */ 1749 NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); 1750 1751 error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, 1752 S_IRUSR | S_IWUSR); 1753 1754 if (error) 1755 goto out; 1756 1757 /* 1758 * Don't dump to non-regular files, files with links, or files 1759 * owned by someone else. 1760 */ 1761 vp = nd.ni_vp; 1762 if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { 1763 VOP_UNLOCK(vp); 1764 vn_close(vp, FWRITE, cred, p); 1765 goto out; 1766 } 1767 if (vp->v_type != VREG || vattr.va_nlink != 1 || 1768 vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || 1769 vattr.va_uid != cred->cr_uid) { 1770 error = EACCES; 1771 VOP_UNLOCK(vp); 1772 vn_close(vp, FWRITE, cred, p); 1773 goto out; 1774 } 1775 VATTR_NULL(&vattr); 1776 vattr.va_size = 0; 1777 VOP_SETATTR(vp, &vattr, cred, p); 1778 pr->ps_acflag |= ACORE; 1779 1780 io.io_proc = p; 1781 io.io_vp = vp; 1782 io.io_cred = cred; 1783 io.io_offset = 0; 1784 VOP_UNLOCK(vp); 1785 vref(vp); 1786 error = vn_close(vp, FWRITE, cred, p); 1787 if (error == 0) 1788 error = coredump_elf(p, &io); 1789 vrele(vp); 1790out: 1791 crfree(cred); 1792 pool_put(&namei_pool, name); 1793 return (error); 1794#endif 1795} 1796 1797#ifndef SMALL_KERNEL 1798int 1799coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len, 1800 int isvnode) 1801{ 1802 struct coredump_iostate *io = cookie; 1803 off_t coffset = 0; 1804 size_t csize; 1805 int chunk, error; 1806 1807 csize = len; 1808 do { 1809 if (sigmask(SIGKILL) & 1810 (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) 1811 return (EINTR); 1812 1813 /* Rest of the loop sleeps with lock held, so... */ 1814 yield(); 1815 1816 chunk = MIN(csize, MAXPHYS); 1817 error = vn_rdwr(UIO_WRITE, io->io_vp, 1818 (caddr_t)data + coffset, chunk, 1819 io->io_offset + coffset, segflg, 1820 IO_UNIT, io->io_cred, NULL, io->io_proc); 1821 if (error && (error != EFAULT || !isvnode)) { 1822 struct process *pr = io->io_proc->p_p; 1823 1824 if (error == ENOSPC) 1825 log(LOG_ERR, 1826 "coredump of %s(%d) failed, filesystem full\n", 1827 pr->ps_comm, pr->ps_pid); 1828 else 1829 log(LOG_ERR, 1830 "coredump of %s(%d), write failed: errno %d\n", 1831 pr->ps_comm, pr->ps_pid, error); 1832 return (error); 1833 } 1834 1835 coffset += chunk; 1836 csize -= chunk; 1837 } while (csize > 0); 1838 1839 io->io_offset += len; 1840 return (0); 1841} 1842 1843void 1844coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) 1845{ 1846 struct coredump_iostate *io = cookie; 1847 1848 uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); 1849} 1850 1851#endif /* !SMALL_KERNEL */ 1852 1853/* 1854 * Nonexistent system call-- signal process (may want to handle it). 1855 * Flag error in case process won't see signal immediately (blocked or ignored). 1856 */ 1857int 1858sys_nosys(struct proc *p, void *v, register_t *retval) 1859{ 1860 ptsignal(p, SIGSYS, STHREAD); 1861 return (ENOSYS); 1862} 1863 1864int 1865sys___thrsigdivert(struct proc *p, void *v, register_t *retval) 1866{ 1867 struct sys___thrsigdivert_args /* { 1868 syscallarg(sigset_t) sigmask; 1869 syscallarg(siginfo_t *) info; 1870 syscallarg(const struct timespec *) timeout; 1871 } */ *uap = v; 1872 struct sigctx ctx; 1873 sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; 1874 siginfo_t si; 1875 uint64_t nsecs = INFSLP; 1876 int timeinvalid = 0; 1877 int error = 0; 1878 1879 memset(&si, 0, sizeof(si)); 1880 1881 if (SCARG(uap, timeout) != NULL) { 1882 struct timespec ts; 1883 if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) 1884 return (error); 1885#ifdef KTRACE 1886 if (KTRPOINT(p, KTR_STRUCT)) 1887 ktrreltimespec(p, &ts); 1888#endif 1889 if (!timespecisvalid(&ts)) 1890 timeinvalid = 1; 1891 else 1892 nsecs = TIMESPEC_TO_NSEC(&ts); 1893 } 1894 1895 dosigsuspend(p, p->p_sigmask &~ mask); 1896 for (;;) { 1897 si.si_signo = cursig(p, &ctx); 1898 if (si.si_signo != 0) { 1899 sigset_t smask = sigmask(si.si_signo); 1900 if (smask & mask) { 1901 atomic_clearbits_int(&p->p_siglist, smask); 1902 error = 0; 1903 break; 1904 } 1905 } 1906 1907 /* per-POSIX, delay this error until after the above */ 1908 if (timeinvalid) 1909 error = EINVAL; 1910 /* per-POSIX, return immediately if timeout is zero-valued */ 1911 if (nsecs == 0) 1912 error = EAGAIN; 1913 1914 if (error != 0) 1915 break; 1916 1917 error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); 1918 } 1919 1920 if (error == 0) { 1921 *retval = si.si_signo; 1922 if (SCARG(uap, info) != NULL) { 1923 error = copyout(&si, SCARG(uap, info), sizeof(si)); 1924#ifdef KTRACE 1925 if (error == 0 && KTRPOINT(p, KTR_STRUCT)) 1926 ktrsiginfo(p, &si); 1927#endif 1928 } 1929 } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { 1930 /* 1931 * Restarting is wrong if there's a timeout, as it'll be 1932 * for the same interval again 1933 */ 1934 error = EINTR; 1935 } 1936 1937 return (error); 1938} 1939 1940void 1941initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) 1942{ 1943 memset(si, 0, sizeof(*si)); 1944 1945 si->si_signo = sig; 1946 si->si_code = code; 1947 if (code == SI_USER) { 1948 si->si_value = val; 1949 } else { 1950 switch (sig) { 1951 case SIGSEGV: 1952 case SIGILL: 1953 case SIGBUS: 1954 case SIGFPE: 1955 si->si_addr = val.sival_ptr; 1956 si->si_trapno = trapno; 1957 break; 1958 case SIGXFSZ: 1959 break; 1960 } 1961 } 1962} 1963 1964int 1965filt_sigattach(struct knote *kn) 1966{ 1967 struct process *pr = curproc->p_p; 1968 int s; 1969 1970 if (kn->kn_id >= NSIG) 1971 return EINVAL; 1972 1973 kn->kn_ptr.p_process = pr; 1974 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1975 1976 s = splhigh(); 1977 klist_insert_locked(&pr->ps_klist, kn); 1978 splx(s); 1979 1980 return (0); 1981} 1982 1983void 1984filt_sigdetach(struct knote *kn) 1985{ 1986 struct process *pr = kn->kn_ptr.p_process; 1987 int s; 1988 1989 s = splhigh(); 1990 klist_remove_locked(&pr->ps_klist, kn); 1991 splx(s); 1992} 1993 1994/* 1995 * signal knotes are shared with proc knotes, so we apply a mask to 1996 * the hint in order to differentiate them from process hints. This 1997 * could be avoided by using a signal-specific knote list, but probably 1998 * isn't worth the trouble. 1999 */ 2000int 2001filt_signal(struct knote *kn, long hint) 2002{ 2003 2004 if (hint & NOTE_SIGNAL) { 2005 hint &= ~NOTE_SIGNAL; 2006 2007 if (kn->kn_id == hint) 2008 kn->kn_data++; 2009 } 2010 return (kn->kn_data != 0); 2011} 2012 2013void 2014userret(struct proc *p) 2015{ 2016 struct sigctx ctx; 2017 int signum; 2018 2019 if (p->p_flag & P_SUSPSINGLE) 2020 single_thread_check(p, 0); 2021 2022 /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ 2023 if (p->p_flag & P_PROFPEND) { 2024 atomic_clearbits_int(&p->p_flag, P_PROFPEND); 2025 KERNEL_LOCK(); 2026 psignal(p, SIGPROF); 2027 KERNEL_UNLOCK(); 2028 } 2029 if (p->p_flag & P_ALRMPEND) { 2030 atomic_clearbits_int(&p->p_flag, P_ALRMPEND); 2031 KERNEL_LOCK(); 2032 psignal(p, SIGVTALRM); 2033 KERNEL_UNLOCK(); 2034 } 2035 2036 if (SIGPENDING(p) != 0) { 2037 while ((signum = cursig(p, &ctx)) != 0) 2038 postsig(p, signum, &ctx); 2039 } 2040 2041 /* 2042 * If P_SIGSUSPEND is still set here, then we still need to restore 2043 * the original sigmask before returning to userspace. Also, this 2044 * might unmask some pending signals, so we need to check a second 2045 * time for signals to post. 2046 */ 2047 if (p->p_flag & P_SIGSUSPEND) { 2048 p->p_sigmask = p->p_oldmask; 2049 atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); 2050 2051 while ((signum = cursig(p, &ctx)) != 0) 2052 postsig(p, signum, &ctx); 2053 } 2054 2055 WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); 2056 2057 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 2058} 2059 2060int 2061single_thread_check_locked(struct proc *p, int deep) 2062{ 2063 struct process *pr = p->p_p; 2064 2065 MUTEX_ASSERT_LOCKED(&pr->ps_mtx); 2066 2067 if (pr->ps_single == NULL || pr->ps_single == p) 2068 return (0); 2069 2070 do { 2071 /* if we're in deep, we need to unwind to the edge */ 2072 if (deep) { 2073 if (pr->ps_flags & PS_SINGLEUNWIND) 2074 return (ERESTART); 2075 if (pr->ps_flags & PS_SINGLEEXIT) 2076 return (EINTR); 2077 } 2078 2079 if (pr->ps_flags & PS_SINGLEEXIT) { 2080 mtx_leave(&pr->ps_mtx); 2081 KERNEL_LOCK(); 2082 exit1(p, 0, 0, EXIT_THREAD_NOCHECK); 2083 /* NOTREACHED */ 2084 } 2085 2086 if (--pr->ps_singlecnt == 0) 2087 wakeup(&pr->ps_singlecnt); 2088 2089 /* not exiting and don't need to unwind, so suspend */ 2090 mtx_leave(&pr->ps_mtx); 2091 2092 SCHED_LOCK(); 2093 p->p_stat = SSTOP; 2094 mi_switch(); 2095 SCHED_UNLOCK(); 2096 mtx_enter(&pr->ps_mtx); 2097 } while (pr->ps_single != NULL); 2098 2099 return (0); 2100} 2101 2102int 2103single_thread_check(struct proc *p, int deep) 2104{ 2105 int error; 2106 2107 mtx_enter(&p->p_p->ps_mtx); 2108 error = single_thread_check_locked(p, deep); 2109 mtx_leave(&p->p_p->ps_mtx); 2110 2111 return error; 2112} 2113 2114/* 2115 * Stop other threads in the process. The mode controls how and 2116 * where the other threads should stop: 2117 * - SINGLE_SUSPEND: stop wherever they are, will later be released (via 2118 * single_thread_clear()) 2119 * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit 2120 * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND 2121 * - SINGLE_EXIT: unwind to kernel boundary and exit 2122 */ 2123int 2124single_thread_set(struct proc *p, int flags) 2125{ 2126 struct process *pr = p->p_p; 2127 struct proc *q; 2128 int error, mode = flags & SINGLE_MASK; 2129 2130 KASSERT(curproc == p); 2131 2132 mtx_enter(&pr->ps_mtx); 2133 error = single_thread_check_locked(p, flags & SINGLE_DEEP); 2134 if (error) { 2135 mtx_leave(&pr->ps_mtx); 2136 return error; 2137 } 2138 2139 switch (mode) { 2140 case SINGLE_SUSPEND: 2141 break; 2142 case SINGLE_UNWIND: 2143 atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2144 break; 2145 case SINGLE_EXIT: 2146 atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); 2147 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); 2148 break; 2149#ifdef DIAGNOSTIC 2150 default: 2151 panic("single_thread_mode = %d", mode); 2152#endif 2153 } 2154 pr->ps_single = p; 2155 pr->ps_singlecnt = pr->ps_threadcnt; 2156 2157 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2158 if (q == p) 2159 continue; 2160 SCHED_LOCK(); 2161 atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); 2162 switch (q->p_stat) { 2163 case SIDL: 2164 case SDEAD: 2165 break; 2166 case SSLEEP: 2167 /* if it's not interruptible, then just have to wait */ 2168 if (q->p_flag & P_SINTR) { 2169 /* merely need to suspend? just stop it */ 2170 if (mode == SINGLE_SUSPEND) { 2171 q->p_stat = SSTOP; 2172 --pr->ps_singlecnt; 2173 break; 2174 } 2175 /* need to unwind or exit, so wake it */ 2176 unsleep(q); 2177 setrunnable(q); 2178 } 2179 break; 2180 case SSTOP: 2181 if (mode == SINGLE_EXIT) { 2182 unsleep(q); 2183 setrunnable(q); 2184 } else 2185 --pr->ps_singlecnt; 2186 break; 2187 case SONPROC: 2188 signotify(q); 2189 /* FALLTHROUGH */ 2190 case SRUN: 2191 break; 2192 } 2193 SCHED_UNLOCK(); 2194 } 2195 2196 /* count ourselfs out */ 2197 --pr->ps_singlecnt; 2198 mtx_leave(&pr->ps_mtx); 2199 2200 if ((flags & SINGLE_NOWAIT) == 0) 2201 single_thread_wait(pr, 1); 2202 2203 return 0; 2204} 2205 2206/* 2207 * Wait for other threads to stop. If recheck is false then the function 2208 * returns non-zero if the caller needs to restart the check else 0 is 2209 * returned. If recheck is true the return value is always 0. 2210 */ 2211int 2212single_thread_wait(struct process *pr, int recheck) 2213{ 2214 int wait; 2215 2216 /* wait until they're all suspended */ 2217 mtx_enter(&pr->ps_mtx); 2218 while ((wait = pr->ps_singlecnt > 0)) { 2219 msleep_nsec(&pr->ps_singlecnt, &pr->ps_mtx, PWAIT, "suspend", 2220 INFSLP); 2221 if (!recheck) 2222 break; 2223 } 2224 mtx_leave(&pr->ps_mtx); 2225 2226 return wait; 2227} 2228 2229void 2230single_thread_clear(struct proc *p, int flag) 2231{ 2232 struct process *pr = p->p_p; 2233 struct proc *q; 2234 2235 KASSERT(pr->ps_single == p); 2236 KASSERT(curproc == p); 2237 2238 mtx_enter(&pr->ps_mtx); 2239 pr->ps_single = NULL; 2240 atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); 2241 2242 TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { 2243 if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) 2244 continue; 2245 atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); 2246 2247 /* 2248 * if the thread was only stopped for single threading 2249 * then clearing that either makes it runnable or puts 2250 * it back into some sleep queue 2251 */ 2252 SCHED_LOCK(); 2253 if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { 2254 if (q->p_wchan == NULL) 2255 setrunnable(q); 2256 else { 2257 atomic_clearbits_int(&q->p_flag, P_WSLEEP); 2258 q->p_stat = SSLEEP; 2259 } 2260 } 2261 SCHED_UNLOCK(); 2262 } 2263 mtx_leave(&pr->ps_mtx); 2264} 2265 2266void 2267sigio_del(struct sigiolst *rmlist) 2268{ 2269 struct sigio *sigio; 2270 2271 while ((sigio = LIST_FIRST(rmlist)) != NULL) { 2272 LIST_REMOVE(sigio, sio_pgsigio); 2273 crfree(sigio->sio_ucred); 2274 free(sigio, M_SIGIO, sizeof(*sigio)); 2275 } 2276} 2277 2278void 2279sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) 2280{ 2281 struct sigio *sigio; 2282 2283 MUTEX_ASSERT_LOCKED(&sigio_lock); 2284 2285 sigio = sir->sir_sigio; 2286 if (sigio != NULL) { 2287 KASSERT(sigio->sio_myref == sir); 2288 sir->sir_sigio = NULL; 2289 2290 if (sigio->sio_pgid > 0) 2291 sigio->sio_proc = NULL; 2292 else 2293 sigio->sio_pgrp = NULL; 2294 LIST_REMOVE(sigio, sio_pgsigio); 2295 2296 LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); 2297 } 2298} 2299 2300void 2301sigio_free(struct sigio_ref *sir) 2302{ 2303 struct sigiolst rmlist; 2304 2305 if (sir->sir_sigio == NULL) 2306 return; 2307 2308 LIST_INIT(&rmlist); 2309 2310 mtx_enter(&sigio_lock); 2311 sigio_unlink(sir, &rmlist); 2312 mtx_leave(&sigio_lock); 2313 2314 sigio_del(&rmlist); 2315} 2316 2317void 2318sigio_freelist(struct sigiolst *sigiolst) 2319{ 2320 struct sigiolst rmlist; 2321 struct sigio *sigio; 2322 2323 if (LIST_EMPTY(sigiolst)) 2324 return; 2325 2326 LIST_INIT(&rmlist); 2327 2328 mtx_enter(&sigio_lock); 2329 while ((sigio = LIST_FIRST(sigiolst)) != NULL) 2330 sigio_unlink(sigio->sio_myref, &rmlist); 2331 mtx_leave(&sigio_lock); 2332 2333 sigio_del(&rmlist); 2334} 2335 2336int 2337sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2338{ 2339 struct sigiolst rmlist; 2340 struct proc *p = curproc; 2341 struct pgrp *pgrp = NULL; 2342 struct process *pr = NULL; 2343 struct sigio *sigio; 2344 int error; 2345 pid_t pgid = *(int *)data; 2346 2347 if (pgid == 0) { 2348 sigio_free(sir); 2349 return (0); 2350 } 2351 2352 if (cmd == TIOCSPGRP) { 2353 if (pgid < 0) 2354 return (EINVAL); 2355 pgid = -pgid; 2356 } 2357 2358 sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); 2359 sigio->sio_pgid = pgid; 2360 sigio->sio_ucred = crhold(p->p_ucred); 2361 sigio->sio_myref = sir; 2362 2363 LIST_INIT(&rmlist); 2364 2365 /* 2366 * The kernel lock, and not sleeping between prfind()/pgfind() and 2367 * linking of the sigio ensure that the process or process group does 2368 * not disappear unexpectedly. 2369 */ 2370 KERNEL_LOCK(); 2371 mtx_enter(&sigio_lock); 2372 2373 if (pgid > 0) { 2374 pr = prfind(pgid); 2375 if (pr == NULL) { 2376 error = ESRCH; 2377 goto fail; 2378 } 2379 2380 /* 2381 * Policy - Don't allow a process to FSETOWN a process 2382 * in another session. 2383 * 2384 * Remove this test to allow maximum flexibility or 2385 * restrict FSETOWN to the current process or process 2386 * group for maximum safety. 2387 */ 2388 if (pr->ps_session != p->p_p->ps_session) { 2389 error = EPERM; 2390 goto fail; 2391 } 2392 2393 if ((pr->ps_flags & PS_EXITING) != 0) { 2394 error = ESRCH; 2395 goto fail; 2396 } 2397 } else /* if (pgid < 0) */ { 2398 pgrp = pgfind(-pgid); 2399 if (pgrp == NULL) { 2400 error = ESRCH; 2401 goto fail; 2402 } 2403 2404 /* 2405 * Policy - Don't allow a process to FSETOWN a process 2406 * in another session. 2407 * 2408 * Remove this test to allow maximum flexibility or 2409 * restrict FSETOWN to the current process or process 2410 * group for maximum safety. 2411 */ 2412 if (pgrp->pg_session != p->p_p->ps_session) { 2413 error = EPERM; 2414 goto fail; 2415 } 2416 } 2417 2418 if (pgid > 0) { 2419 sigio->sio_proc = pr; 2420 LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); 2421 } else { 2422 sigio->sio_pgrp = pgrp; 2423 LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 2424 } 2425 2426 sigio_unlink(sir, &rmlist); 2427 sir->sir_sigio = sigio; 2428 2429 mtx_leave(&sigio_lock); 2430 KERNEL_UNLOCK(); 2431 2432 sigio_del(&rmlist); 2433 2434 return (0); 2435 2436fail: 2437 mtx_leave(&sigio_lock); 2438 KERNEL_UNLOCK(); 2439 2440 crfree(sigio->sio_ucred); 2441 free(sigio, M_SIGIO, sizeof(*sigio)); 2442 2443 return (error); 2444} 2445 2446void 2447sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) 2448{ 2449 struct sigio *sigio; 2450 pid_t pgid = 0; 2451 2452 mtx_enter(&sigio_lock); 2453 sigio = sir->sir_sigio; 2454 if (sigio != NULL) 2455 pgid = sigio->sio_pgid; 2456 mtx_leave(&sigio_lock); 2457 2458 if (cmd == TIOCGPGRP) 2459 pgid = -pgid; 2460 2461 *(int *)data = pgid; 2462} 2463 2464void 2465sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) 2466{ 2467 struct sigiolst rmlist; 2468 struct sigio *newsigio, *sigio; 2469 2470 sigio_free(dst); 2471 2472 if (src->sir_sigio == NULL) 2473 return; 2474 2475 newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); 2476 LIST_INIT(&rmlist); 2477 2478 mtx_enter(&sigio_lock); 2479 2480 sigio = src->sir_sigio; 2481 if (sigio == NULL) { 2482 mtx_leave(&sigio_lock); 2483 free(newsigio, M_SIGIO, sizeof(*newsigio)); 2484 return; 2485 } 2486 2487 newsigio->sio_pgid = sigio->sio_pgid; 2488 newsigio->sio_ucred = crhold(sigio->sio_ucred); 2489 newsigio->sio_myref = dst; 2490 if (newsigio->sio_pgid > 0) { 2491 newsigio->sio_proc = sigio->sio_proc; 2492 LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, 2493 sio_pgsigio); 2494 } else { 2495 newsigio->sio_pgrp = sigio->sio_pgrp; 2496 LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, 2497 sio_pgsigio); 2498 } 2499 2500 sigio_unlink(dst, &rmlist); 2501 dst->sir_sigio = newsigio; 2502 2503 mtx_leave(&sigio_lock); 2504 2505 sigio_del(&rmlist); 2506} 2507