1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 35 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 36 */ 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/sysproto.h> 44 #include <sys/signalvar.h> 45 #include <sys/resourcevar.h> 46 #include <sys/vnode.h> 47 #include <sys/event.h> 48 #include <sys/proc.h> 49 #include <sys/nlookup.h> 50 #include <sys/pioctl.h> 51 #include <sys/acct.h> 52 #include <sys/fcntl.h> 53 #include <sys/lock.h> 54 #include <sys/wait.h> 55 #include <sys/ktrace.h> 56 #include <sys/syslog.h> 57 #include <sys/stat.h> 58 #include <sys/sysent.h> 59 #include <sys/sysctl.h> 60 #include <sys/malloc.h> 61 #include <sys/interrupt.h> 62 #include <sys/unistd.h> 63 #include <sys/kern_syscall.h> 64 #include <sys/vkernel.h> 65 66 #include <sys/signal2.h> 67 #include <sys/thread2.h> 68 #include <sys/spinlock2.h> 69 70 #include <machine/cpu.h> 71 #include <machine/smp.h> 72 73 static int coredump(struct lwp *, int); 74 static char *expand_name(const char *, uid_t, pid_t); 75 static int dokillpg(int sig, int pgid, int all); 76 static int sig_ffs(sigset_t *set); 77 static int sigprop(int sig); 78 static void lwp_signotify(struct lwp *lp); 79 static void lwp_signotify_remote(void *arg); 80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 81 struct timespec *timeout); 82 83 static int filt_sigattach(struct knote *kn); 84 static void filt_sigdetach(struct knote *kn); 85 static int filt_signal(struct knote *kn, long hint); 86 87 struct filterops sig_filtops = 88 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 89 90 static int kern_logsigexit = 1; 91 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 92 &kern_logsigexit, 0, 93 "Log processes quitting on abnormal signals to syslog(3)"); 94 95 /* 96 * Can process p, with pcred pc, send the signal sig to process q? 97 */ 98 #define CANSIGNAL(q, sig) \ 99 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 100 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 101 102 /* 103 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 104 */ 105 #define CANSIGIO(ruid, uc, q) \ 106 ((uc)->cr_uid == 0 || \ 107 (ruid) == (q)->p_ucred->cr_ruid || \ 108 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 109 (ruid) == (q)->p_ucred->cr_uid || \ 110 (uc)->cr_uid == (q)->p_ucred->cr_uid) 111 112 int sugid_coredump; 113 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 114 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 115 116 static int do_coredump = 1; 117 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 118 &do_coredump, 0, "Enable/Disable coredumps"); 119 120 /* 121 * Signal properties and actions. 122 * The array below categorizes the signals and their default actions 123 * according to the following properties: 124 */ 125 #define SA_KILL 0x01 /* terminates process by default */ 126 #define SA_CORE 0x02 /* ditto and coredumps */ 127 #define SA_STOP 0x04 /* suspend process */ 128 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 129 #define SA_IGNORE 0x10 /* ignore by default */ 130 #define SA_CONT 0x20 /* continue if suspended */ 131 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 132 #define SA_CKPT 0x80 /* checkpoint process */ 133 134 135 static int sigproptbl[NSIG] = { 136 SA_KILL, /* SIGHUP */ 137 SA_KILL, /* SIGINT */ 138 SA_KILL|SA_CORE, /* SIGQUIT */ 139 SA_KILL|SA_CORE, /* SIGILL */ 140 SA_KILL|SA_CORE, /* SIGTRAP */ 141 SA_KILL|SA_CORE, /* SIGABRT */ 142 SA_KILL|SA_CORE, /* SIGEMT */ 143 SA_KILL|SA_CORE, /* SIGFPE */ 144 SA_KILL, /* SIGKILL */ 145 SA_KILL|SA_CORE, /* SIGBUS */ 146 SA_KILL|SA_CORE, /* SIGSEGV */ 147 SA_KILL|SA_CORE, /* SIGSYS */ 148 SA_KILL, /* SIGPIPE */ 149 SA_KILL, /* SIGALRM */ 150 SA_KILL, /* SIGTERM */ 151 SA_IGNORE, /* SIGURG */ 152 SA_STOP, /* SIGSTOP */ 153 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 154 SA_IGNORE|SA_CONT, /* SIGCONT */ 155 SA_IGNORE, /* SIGCHLD */ 156 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 157 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 158 SA_IGNORE, /* SIGIO */ 159 SA_KILL, /* SIGXCPU */ 160 SA_KILL, /* SIGXFSZ */ 161 SA_KILL, /* SIGVTALRM */ 162 SA_KILL, /* SIGPROF */ 163 SA_IGNORE, /* SIGWINCH */ 164 SA_IGNORE, /* SIGINFO */ 165 SA_KILL, /* SIGUSR1 */ 166 SA_KILL, /* SIGUSR2 */ 167 SA_IGNORE, /* SIGTHR */ 168 SA_CKPT, /* SIGCKPT */ 169 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 170 SA_IGNORE, 171 SA_IGNORE, 172 SA_IGNORE, 173 SA_IGNORE, 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 201 }; 202 203 static __inline int 204 sigprop(int sig) 205 { 206 207 if (sig > 0 && sig < NSIG) 208 return (sigproptbl[_SIG_IDX(sig)]); 209 return (0); 210 } 211 212 static __inline int 213 sig_ffs(sigset_t *set) 214 { 215 int i; 216 217 for (i = 0; i < _SIG_WORDS; i++) 218 if (set->__bits[i]) 219 return (ffs(set->__bits[i]) + (i * 32)); 220 return (0); 221 } 222 223 /* 224 * No requirements. 225 */ 226 int 227 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 228 { 229 struct thread *td = curthread; 230 struct proc *p = td->td_proc; 231 struct lwp *lp; 232 struct sigacts *ps = p->p_sigacts; 233 234 if (sig <= 0 || sig > _SIG_MAXSIG) 235 return (EINVAL); 236 237 lwkt_gettoken(&p->p_token); 238 239 if (oact) { 240 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 241 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 242 oact->sa_flags = 0; 243 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 244 oact->sa_flags |= SA_ONSTACK; 245 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 246 oact->sa_flags |= SA_RESTART; 247 if (SIGISMEMBER(ps->ps_sigreset, sig)) 248 oact->sa_flags |= SA_RESETHAND; 249 if (SIGISMEMBER(ps->ps_signodefer, sig)) 250 oact->sa_flags |= SA_NODEFER; 251 if (SIGISMEMBER(ps->ps_siginfo, sig)) 252 oact->sa_flags |= SA_SIGINFO; 253 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 254 oact->sa_flags |= SA_NOCLDSTOP; 255 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 256 oact->sa_flags |= SA_NOCLDWAIT; 257 } 258 if (act) { 259 /* 260 * Check for invalid requests. KILL and STOP cannot be 261 * caught. 262 */ 263 if (sig == SIGKILL || sig == SIGSTOP) { 264 if (act->sa_handler != SIG_DFL) { 265 lwkt_reltoken(&p->p_token); 266 return (EINVAL); 267 } 268 } 269 270 /* 271 * Change setting atomically. 272 */ 273 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 274 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 275 if (act->sa_flags & SA_SIGINFO) { 276 ps->ps_sigact[_SIG_IDX(sig)] = 277 (__sighandler_t *)act->sa_sigaction; 278 SIGADDSET(ps->ps_siginfo, sig); 279 } else { 280 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 281 SIGDELSET(ps->ps_siginfo, sig); 282 } 283 if (!(act->sa_flags & SA_RESTART)) 284 SIGADDSET(ps->ps_sigintr, sig); 285 else 286 SIGDELSET(ps->ps_sigintr, sig); 287 if (act->sa_flags & SA_ONSTACK) 288 SIGADDSET(ps->ps_sigonstack, sig); 289 else 290 SIGDELSET(ps->ps_sigonstack, sig); 291 if (act->sa_flags & SA_RESETHAND) 292 SIGADDSET(ps->ps_sigreset, sig); 293 else 294 SIGDELSET(ps->ps_sigreset, sig); 295 if (act->sa_flags & SA_NODEFER) 296 SIGADDSET(ps->ps_signodefer, sig); 297 else 298 SIGDELSET(ps->ps_signodefer, sig); 299 if (sig == SIGCHLD) { 300 if (act->sa_flags & SA_NOCLDSTOP) 301 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 302 else 303 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 304 if (act->sa_flags & SA_NOCLDWAIT) { 305 /* 306 * Paranoia: since SA_NOCLDWAIT is implemented 307 * by reparenting the dying child to PID 1 (and 308 * trust it to reap the zombie), PID 1 itself 309 * is forbidden to set SA_NOCLDWAIT. 310 */ 311 if (p->p_pid == 1) 312 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 313 else 314 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 315 } else { 316 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 317 } 318 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 319 ps->ps_flag |= PS_CLDSIGIGN; 320 else 321 ps->ps_flag &= ~PS_CLDSIGIGN; 322 } 323 /* 324 * Set bit in p_sigignore for signals that are set to SIG_IGN, 325 * and for signals set to SIG_DFL where the default is to 326 * ignore. However, don't put SIGCONT in p_sigignore, as we 327 * have to restart the process. 328 * 329 * Also remove the signal from the process and lwp signal 330 * list. 331 */ 332 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 333 (sigprop(sig) & SA_IGNORE && 334 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 335 SIGDELSET(p->p_siglist, sig); 336 FOREACH_LWP_IN_PROC(lp, p) { 337 spin_lock(&lp->lwp_spin); 338 SIGDELSET(lp->lwp_siglist, sig); 339 spin_unlock(&lp->lwp_spin); 340 } 341 if (sig != SIGCONT) { 342 /* easier in ksignal */ 343 SIGADDSET(p->p_sigignore, sig); 344 } 345 SIGDELSET(p->p_sigcatch, sig); 346 } else { 347 SIGDELSET(p->p_sigignore, sig); 348 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 349 SIGDELSET(p->p_sigcatch, sig); 350 else 351 SIGADDSET(p->p_sigcatch, sig); 352 } 353 } 354 lwkt_reltoken(&p->p_token); 355 return (0); 356 } 357 358 int 359 sys_sigaction(struct sigaction_args *uap) 360 { 361 struct sigaction act, oact; 362 struct sigaction *actp, *oactp; 363 int error; 364 365 actp = (uap->act != NULL) ? &act : NULL; 366 oactp = (uap->oact != NULL) ? &oact : NULL; 367 if (actp) { 368 error = copyin(uap->act, actp, sizeof(act)); 369 if (error) 370 return (error); 371 } 372 error = kern_sigaction(uap->sig, actp, oactp); 373 if (oactp && !error) { 374 error = copyout(oactp, uap->oact, sizeof(oact)); 375 } 376 return (error); 377 } 378 379 /* 380 * Initialize signal state for process 0; 381 * set to ignore signals that are ignored by default. 382 */ 383 void 384 siginit(struct proc *p) 385 { 386 int i; 387 388 for (i = 1; i <= NSIG; i++) 389 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 390 SIGADDSET(p->p_sigignore, i); 391 } 392 393 /* 394 * Reset signals for an exec of the specified process. 395 */ 396 void 397 execsigs(struct proc *p) 398 { 399 struct sigacts *ps = p->p_sigacts; 400 struct lwp *lp; 401 int sig; 402 403 lp = ONLY_LWP_IN_PROC(p); 404 405 /* 406 * Reset caught signals. Held signals remain held 407 * through p_sigmask (unless they were caught, 408 * and are now ignored by default). 409 */ 410 while (SIGNOTEMPTY(p->p_sigcatch)) { 411 sig = sig_ffs(&p->p_sigcatch); 412 SIGDELSET(p->p_sigcatch, sig); 413 if (sigprop(sig) & SA_IGNORE) { 414 if (sig != SIGCONT) 415 SIGADDSET(p->p_sigignore, sig); 416 SIGDELSET(p->p_siglist, sig); 417 /* don't need spinlock */ 418 SIGDELSET(lp->lwp_siglist, sig); 419 } 420 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 421 } 422 423 /* 424 * Reset stack state to the user stack. 425 * Clear set of signals caught on the signal stack. 426 */ 427 lp->lwp_sigstk.ss_flags = SS_DISABLE; 428 lp->lwp_sigstk.ss_size = 0; 429 lp->lwp_sigstk.ss_sp = NULL; 430 lp->lwp_flags &= ~LWP_ALTSTACK; 431 /* 432 * Reset no zombies if child dies flag as Solaris does. 433 */ 434 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 435 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 436 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 437 } 438 439 /* 440 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 441 * 442 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 443 * p == curproc. 444 */ 445 int 446 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 447 { 448 struct thread *td = curthread; 449 struct lwp *lp = td->td_lwp; 450 struct proc *p = td->td_proc; 451 int error; 452 453 lwkt_gettoken(&p->p_token); 454 455 if (oset != NULL) 456 *oset = lp->lwp_sigmask; 457 458 error = 0; 459 if (set != NULL) { 460 switch (how) { 461 case SIG_BLOCK: 462 SIG_CANTMASK(*set); 463 SIGSETOR(lp->lwp_sigmask, *set); 464 break; 465 case SIG_UNBLOCK: 466 SIGSETNAND(lp->lwp_sigmask, *set); 467 break; 468 case SIG_SETMASK: 469 SIG_CANTMASK(*set); 470 lp->lwp_sigmask = *set; 471 break; 472 default: 473 error = EINVAL; 474 break; 475 } 476 } 477 478 lwkt_reltoken(&p->p_token); 479 480 return (error); 481 } 482 483 /* 484 * sigprocmask() 485 * 486 * MPSAFE 487 */ 488 int 489 sys_sigprocmask(struct sigprocmask_args *uap) 490 { 491 sigset_t set, oset; 492 sigset_t *setp, *osetp; 493 int error; 494 495 setp = (uap->set != NULL) ? &set : NULL; 496 osetp = (uap->oset != NULL) ? &oset : NULL; 497 if (setp) { 498 error = copyin(uap->set, setp, sizeof(set)); 499 if (error) 500 return (error); 501 } 502 error = kern_sigprocmask(uap->how, setp, osetp); 503 if (osetp && !error) { 504 error = copyout(osetp, uap->oset, sizeof(oset)); 505 } 506 return (error); 507 } 508 509 /* 510 * MPSAFE 511 */ 512 int 513 kern_sigpending(struct __sigset *set) 514 { 515 struct lwp *lp = curthread->td_lwp; 516 517 *set = lwp_sigpend(lp); 518 519 return (0); 520 } 521 522 /* 523 * MPSAFE 524 */ 525 int 526 sys_sigpending(struct sigpending_args *uap) 527 { 528 sigset_t set; 529 int error; 530 531 error = kern_sigpending(&set); 532 533 if (error == 0) 534 error = copyout(&set, uap->set, sizeof(set)); 535 return (error); 536 } 537 538 /* 539 * Suspend process until signal, providing mask to be set 540 * in the meantime. 541 * 542 * MPSAFE 543 */ 544 int 545 kern_sigsuspend(struct __sigset *set) 546 { 547 struct thread *td = curthread; 548 struct lwp *lp = td->td_lwp; 549 struct proc *p = td->td_proc; 550 struct sigacts *ps = p->p_sigacts; 551 552 /* 553 * When returning from sigsuspend, we want 554 * the old mask to be restored after the 555 * signal handler has finished. Thus, we 556 * save it here and mark the sigacts structure 557 * to indicate this. 558 */ 559 lp->lwp_oldsigmask = lp->lwp_sigmask; 560 lp->lwp_flags |= LWP_OLDMASK; 561 562 SIG_CANTMASK(*set); 563 lp->lwp_sigmask = *set; 564 while (tsleep(ps, PCATCH, "pause", 0) == 0) 565 /* void */; 566 /* always return EINTR rather than ERESTART... */ 567 return (EINTR); 568 } 569 570 /* 571 * Note nonstandard calling convention: libc stub passes mask, not 572 * pointer, to save a copyin. 573 * 574 * MPSAFE 575 */ 576 int 577 sys_sigsuspend(struct sigsuspend_args *uap) 578 { 579 sigset_t mask; 580 int error; 581 582 error = copyin(uap->sigmask, &mask, sizeof(mask)); 583 if (error) 584 return (error); 585 586 error = kern_sigsuspend(&mask); 587 588 return (error); 589 } 590 591 /* 592 * MPSAFE 593 */ 594 int 595 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 596 { 597 struct thread *td = curthread; 598 struct lwp *lp = td->td_lwp; 599 struct proc *p = td->td_proc; 600 601 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 602 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 603 604 if (oss) 605 *oss = lp->lwp_sigstk; 606 607 if (ss) { 608 if (ss->ss_flags & ~SS_DISABLE) 609 return (EINVAL); 610 if (ss->ss_flags & SS_DISABLE) { 611 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 612 return (EINVAL); 613 lp->lwp_flags &= ~LWP_ALTSTACK; 614 lp->lwp_sigstk.ss_flags = ss->ss_flags; 615 } else { 616 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 617 return (ENOMEM); 618 lp->lwp_flags |= LWP_ALTSTACK; 619 lp->lwp_sigstk = *ss; 620 } 621 } 622 623 return (0); 624 } 625 626 /* 627 * MPSAFE 628 */ 629 int 630 sys_sigaltstack(struct sigaltstack_args *uap) 631 { 632 stack_t ss, oss; 633 int error; 634 635 if (uap->ss) { 636 error = copyin(uap->ss, &ss, sizeof(ss)); 637 if (error) 638 return (error); 639 } 640 641 error = kern_sigaltstack(uap->ss ? &ss : NULL, 642 uap->oss ? &oss : NULL); 643 644 if (error == 0 && uap->oss) 645 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 646 return (error); 647 } 648 649 /* 650 * Common code for kill process group/broadcast kill. 651 * cp is calling process. 652 */ 653 struct killpg_info { 654 int nfound; 655 int sig; 656 }; 657 658 static int killpg_all_callback(struct proc *p, void *data); 659 660 static int 661 dokillpg(int sig, int pgid, int all) 662 { 663 struct killpg_info info; 664 struct proc *cp = curproc; 665 struct proc *p; 666 struct pgrp *pgrp; 667 668 info.nfound = 0; 669 info.sig = sig; 670 671 if (all) { 672 /* 673 * broadcast 674 */ 675 allproc_scan(killpg_all_callback, &info); 676 } else { 677 if (pgid == 0) { 678 /* 679 * zero pgid means send to my process group. 680 */ 681 pgrp = cp->p_pgrp; 682 pgref(pgrp); 683 } else { 684 pgrp = pgfind(pgid); 685 if (pgrp == NULL) 686 return (ESRCH); 687 } 688 689 /* 690 * Must interlock all signals against fork 691 */ 692 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 693 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 694 if (p->p_pid <= 1 || 695 p->p_stat == SZOMB || 696 (p->p_flags & P_SYSTEM) || 697 !CANSIGNAL(p, sig)) { 698 continue; 699 } 700 ++info.nfound; 701 if (sig) 702 ksignal(p, sig); 703 } 704 lockmgr(&pgrp->pg_lock, LK_RELEASE); 705 pgrel(pgrp); 706 } 707 return (info.nfound ? 0 : ESRCH); 708 } 709 710 static int 711 killpg_all_callback(struct proc *p, void *data) 712 { 713 struct killpg_info *info = data; 714 715 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 716 p == curproc || !CANSIGNAL(p, info->sig)) { 717 return (0); 718 } 719 ++info->nfound; 720 if (info->sig) 721 ksignal(p, info->sig); 722 return(0); 723 } 724 725 /* 726 * Send a general signal to a process or LWPs within that process. 727 * 728 * Note that new signals cannot be sent if a process is exiting or already 729 * a zombie, but we return success anyway as userland is likely to not handle 730 * the race properly. 731 * 732 * No requirements. 733 */ 734 int 735 kern_kill(int sig, pid_t pid, lwpid_t tid) 736 { 737 int t; 738 739 if ((u_int)sig > _SIG_MAXSIG) 740 return (EINVAL); 741 742 lwkt_gettoken(&proc_token); 743 744 if (pid > 0) { 745 struct proc *p; 746 struct lwp *lp = NULL; 747 748 /* 749 * Send a signal to a single process. If the kill() is 750 * racing an exiting process which has not yet been reaped 751 * act as though the signal was delivered successfully but 752 * don't actually try to deliver the signal. 753 */ 754 if ((p = pfind(pid)) == NULL) { 755 if ((p = zpfind(pid)) == NULL) { 756 lwkt_reltoken(&proc_token); 757 return (ESRCH); 758 } 759 lwkt_reltoken(&proc_token); 760 PRELE(p); 761 return (0); 762 } 763 lwkt_gettoken(&p->p_token); 764 if (!CANSIGNAL(p, sig)) { 765 lwkt_reltoken(&p->p_token); 766 PRELE(p); 767 lwkt_reltoken(&proc_token); 768 return (EPERM); 769 } 770 771 /* 772 * NOP if the process is exiting. Note that lwpsignal() is 773 * called directly with P_WEXIT set to kill individual LWPs 774 * during exit, which is allowed. 775 */ 776 if (p->p_flags & P_WEXIT) { 777 lwkt_reltoken(&p->p_token); 778 PRELE(p); 779 lwkt_reltoken(&proc_token); 780 return (0); 781 } 782 if (tid != -1) { 783 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 784 if (lp == NULL) { 785 lwkt_reltoken(&p->p_token); 786 PRELE(p); 787 lwkt_reltoken(&proc_token); 788 return (ESRCH); 789 } 790 } 791 if (sig) 792 lwpsignal(p, lp, sig); 793 lwkt_reltoken(&p->p_token); 794 PRELE(p); 795 lwkt_reltoken(&proc_token); 796 return (0); 797 } 798 799 /* 800 * If we come here, pid is a special broadcast pid. 801 * This doesn't mix with a tid. 802 */ 803 if (tid != -1) { 804 lwkt_reltoken(&proc_token); 805 return (EINVAL); 806 } 807 switch (pid) { 808 case -1: /* broadcast signal */ 809 t = (dokillpg(sig, 0, 1)); 810 break; 811 case 0: /* signal own process group */ 812 t = (dokillpg(sig, 0, 0)); 813 break; 814 default: /* negative explicit process group */ 815 t = (dokillpg(sig, -pid, 0)); 816 break; 817 } 818 lwkt_reltoken(&proc_token); 819 return t; 820 } 821 822 int 823 sys_kill(struct kill_args *uap) 824 { 825 int error; 826 827 error = kern_kill(uap->signum, uap->pid, -1); 828 return (error); 829 } 830 831 int 832 sys_lwp_kill(struct lwp_kill_args *uap) 833 { 834 int error; 835 pid_t pid = uap->pid; 836 837 /* 838 * A tid is mandatory for lwp_kill(), otherwise 839 * you could simply use kill(). 840 */ 841 if (uap->tid == -1) 842 return (EINVAL); 843 844 /* 845 * To save on a getpid() function call for intra-process 846 * signals, pid == -1 means current process. 847 */ 848 if (pid == -1) 849 pid = curproc->p_pid; 850 851 error = kern_kill(uap->signum, pid, uap->tid); 852 return (error); 853 } 854 855 /* 856 * Send a signal to a process group. 857 */ 858 void 859 gsignal(int pgid, int sig) 860 { 861 struct pgrp *pgrp; 862 863 if (pgid && (pgrp = pgfind(pgid))) 864 pgsignal(pgrp, sig, 0); 865 } 866 867 /* 868 * Send a signal to a process group. If checktty is 1, 869 * limit to members which have a controlling terminal. 870 * 871 * pg_lock interlocks against a fork that might be in progress, to 872 * ensure that the new child process picks up the signal. 873 */ 874 void 875 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 876 { 877 struct proc *p; 878 879 /* 880 * Must interlock all signals against fork 881 */ 882 if (pgrp) { 883 pgref(pgrp); 884 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 885 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 886 if (checkctty == 0 || p->p_flags & P_CONTROLT) 887 ksignal(p, sig); 888 } 889 lockmgr(&pgrp->pg_lock, LK_RELEASE); 890 pgrel(pgrp); 891 } 892 } 893 894 /* 895 * Send a signal caused by a trap to the current lwp. If it will be caught 896 * immediately, deliver it with correct code. Otherwise, post it normally. 897 * 898 * These signals may ONLY be delivered to the specified lwp and may never 899 * be delivered to the process generically. 900 */ 901 void 902 trapsignal(struct lwp *lp, int sig, u_long code) 903 { 904 struct proc *p = lp->lwp_proc; 905 struct sigacts *ps = p->p_sigacts; 906 907 /* 908 * If we are a virtual kernel running an emulated user process 909 * context, switch back to the virtual kernel context before 910 * trying to post the signal. 911 */ 912 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 913 struct trapframe *tf = lp->lwp_md.md_regs; 914 tf->tf_trapno = 0; 915 vkernel_trap(lp, tf); 916 } 917 918 919 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 920 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 921 lp->lwp_ru.ru_nsignals++; 922 #ifdef KTRACE 923 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 924 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 925 &lp->lwp_sigmask, code); 926 #endif 927 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 928 &lp->lwp_sigmask, code); 929 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 930 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 931 SIGADDSET(lp->lwp_sigmask, sig); 932 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 933 /* 934 * See kern_sigaction() for origin of this code. 935 */ 936 SIGDELSET(p->p_sigcatch, sig); 937 if (sig != SIGCONT && 938 sigprop(sig) & SA_IGNORE) 939 SIGADDSET(p->p_sigignore, sig); 940 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 941 } 942 } else { 943 lp->lwp_code = code; /* XXX for core dump/debugger */ 944 lp->lwp_sig = sig; /* XXX to verify code */ 945 lwpsignal(p, lp, sig); 946 } 947 } 948 949 /* 950 * Find a suitable lwp to deliver the signal to. Returns NULL if all 951 * lwps hold the signal blocked. 952 * 953 * Caller must hold p->p_token. 954 * 955 * Returns a lp or NULL. If non-NULL the lp is held and its token is 956 * acquired. 957 */ 958 static struct lwp * 959 find_lwp_for_signal(struct proc *p, int sig) 960 { 961 struct lwp *lp; 962 struct lwp *run, *sleep, *stop; 963 964 /* 965 * If the running/preempted thread belongs to the proc to which 966 * the signal is being delivered and this thread does not block 967 * the signal, then we can avoid a context switch by delivering 968 * the signal to this thread, because it will return to userland 969 * soon anyways. 970 */ 971 lp = lwkt_preempted_proc(); 972 if (lp != NULL && lp->lwp_proc == p) { 973 LWPHOLD(lp); 974 lwkt_gettoken(&lp->lwp_token); 975 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 976 /* return w/ token held */ 977 return (lp); 978 } 979 lwkt_reltoken(&lp->lwp_token); 980 LWPRELE(lp); 981 } 982 983 run = sleep = stop = NULL; 984 FOREACH_LWP_IN_PROC(lp, p) { 985 /* 986 * If the signal is being blocked by the lwp, then this 987 * lwp is not eligible for receiving the signal. 988 */ 989 LWPHOLD(lp); 990 lwkt_gettoken(&lp->lwp_token); 991 992 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 993 lwkt_reltoken(&lp->lwp_token); 994 LWPRELE(lp); 995 continue; 996 } 997 998 switch (lp->lwp_stat) { 999 case LSRUN: 1000 if (sleep) { 1001 lwkt_token_swap(); 1002 lwkt_reltoken(&sleep->lwp_token); 1003 LWPRELE(sleep); 1004 sleep = NULL; 1005 run = lp; 1006 } else if (stop) { 1007 lwkt_token_swap(); 1008 lwkt_reltoken(&stop->lwp_token); 1009 LWPRELE(stop); 1010 stop = NULL; 1011 run = lp; 1012 } else { 1013 run = lp; 1014 } 1015 break; 1016 case LSSLEEP: 1017 if (lp->lwp_flags & LWP_SINTR) { 1018 if (sleep) { 1019 lwkt_reltoken(&lp->lwp_token); 1020 LWPRELE(lp); 1021 } else if (stop) { 1022 lwkt_token_swap(); 1023 lwkt_reltoken(&stop->lwp_token); 1024 LWPRELE(stop); 1025 stop = NULL; 1026 sleep = lp; 1027 } else { 1028 sleep = lp; 1029 } 1030 } else { 1031 lwkt_reltoken(&lp->lwp_token); 1032 LWPRELE(lp); 1033 } 1034 break; 1035 case LSSTOP: 1036 if (sleep) { 1037 lwkt_reltoken(&lp->lwp_token); 1038 LWPRELE(lp); 1039 } else if (stop) { 1040 lwkt_reltoken(&lp->lwp_token); 1041 LWPRELE(lp); 1042 } else { 1043 stop = lp; 1044 } 1045 break; 1046 } 1047 if (run) 1048 break; 1049 } 1050 1051 if (run != NULL) 1052 return (run); 1053 else if (sleep != NULL) 1054 return (sleep); 1055 else 1056 return (stop); 1057 } 1058 1059 /* 1060 * Send the signal to the process. If the signal has an action, the action 1061 * is usually performed by the target process rather than the caller; we add 1062 * the signal to the set of pending signals for the process. 1063 * 1064 * Exceptions: 1065 * o When a stop signal is sent to a sleeping process that takes the 1066 * default action, the process is stopped without awakening it. 1067 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1068 * regardless of the signal action (eg, blocked or ignored). 1069 * 1070 * Other ignored signals are discarded immediately. 1071 * 1072 * If the caller wishes to call this function from a hard code section the 1073 * caller must already hold p->p_token (see kern_clock.c). 1074 * 1075 * No requirements. 1076 */ 1077 void 1078 ksignal(struct proc *p, int sig) 1079 { 1080 lwpsignal(p, NULL, sig); 1081 } 1082 1083 /* 1084 * The core for ksignal. lp may be NULL, then a suitable thread 1085 * will be chosen. If not, lp MUST be a member of p. 1086 * 1087 * If the caller wishes to call this function from a hard code section the 1088 * caller must already hold p->p_token. 1089 * 1090 * No requirements. 1091 */ 1092 void 1093 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1094 { 1095 struct proc *q; 1096 sig_t action; 1097 int prop; 1098 1099 if (sig > _SIG_MAXSIG || sig <= 0) { 1100 kprintf("lwpsignal: signal %d\n", sig); 1101 panic("lwpsignal signal number"); 1102 } 1103 1104 KKASSERT(lp == NULL || lp->lwp_proc == p); 1105 1106 /* 1107 * We don't want to race... well, all sorts of things. Get appropriate 1108 * tokens. 1109 * 1110 * Don't try to deliver a generic signal to an exiting process, 1111 * the signal structures could be in flux. We check the LWP later 1112 * on. 1113 */ 1114 PHOLD(p); 1115 lwkt_gettoken(&p->p_token); 1116 if (lp) { 1117 LWPHOLD(lp); 1118 lwkt_gettoken(&lp->lwp_token); 1119 } else if (p->p_flags & P_WEXIT) { 1120 goto out; 1121 } 1122 1123 prop = sigprop(sig); 1124 1125 /* 1126 * If proc is traced, always give parent a chance; 1127 * if signal event is tracked by procfs, give *that* 1128 * a chance, as well. 1129 */ 1130 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1131 action = SIG_DFL; 1132 } else { 1133 /* 1134 * Do not try to deliver signals to an exiting lwp. Note 1135 * that we must still deliver the signal if P_WEXIT is set 1136 * in the process flags. 1137 */ 1138 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT)) { 1139 if (lp) { 1140 lwkt_reltoken(&lp->lwp_token); 1141 LWPRELE(lp); 1142 } 1143 lwkt_reltoken(&p->p_token); 1144 PRELE(p); 1145 return; 1146 } 1147 1148 /* 1149 * If the signal is being ignored, then we forget about 1150 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1151 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1152 */ 1153 if (SIGISMEMBER(p->p_sigignore, sig)) { 1154 /* 1155 * Even if a signal is set SIG_IGN, it may still be 1156 * lurking in a kqueue. 1157 */ 1158 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1159 if (lp) { 1160 lwkt_reltoken(&lp->lwp_token); 1161 LWPRELE(lp); 1162 } 1163 lwkt_reltoken(&p->p_token); 1164 PRELE(p); 1165 return; 1166 } 1167 if (SIGISMEMBER(p->p_sigcatch, sig)) 1168 action = SIG_CATCH; 1169 else 1170 action = SIG_DFL; 1171 } 1172 1173 /* 1174 * If continuing, clear any pending STOP signals. 1175 */ 1176 if (prop & SA_CONT) 1177 SIG_STOPSIGMASK(p->p_siglist); 1178 1179 if (prop & SA_STOP) { 1180 /* 1181 * If sending a tty stop signal to a member of an orphaned 1182 * process group, discard the signal here if the action 1183 * is default; don't stop the process below if sleeping, 1184 * and don't clear any pending SIGCONT. 1185 */ 1186 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1187 action == SIG_DFL) { 1188 lwkt_reltoken(&p->p_token); 1189 PRELE(p); 1190 return; 1191 } 1192 SIG_CONTSIGMASK(p->p_siglist); 1193 p->p_flags &= ~P_CONTINUED; 1194 } 1195 1196 if (p->p_stat == SSTOP) { 1197 /* 1198 * Nobody can handle this signal, add it to the lwp or 1199 * process pending list 1200 */ 1201 if (lp) { 1202 spin_lock(&lp->lwp_spin); 1203 SIGADDSET(lp->lwp_siglist, sig); 1204 spin_unlock(&lp->lwp_spin); 1205 } else { 1206 SIGADDSET(p->p_siglist, sig); 1207 } 1208 1209 /* 1210 * If the process is stopped and is being traced, then no 1211 * further action is necessary. 1212 */ 1213 if (p->p_flags & P_TRACED) 1214 goto out; 1215 1216 /* 1217 * If the process is stopped and receives a KILL signal, 1218 * make the process runnable. 1219 */ 1220 if (sig == SIGKILL) { 1221 proc_unstop(p); 1222 goto active_process; 1223 } 1224 1225 /* 1226 * If the process is stopped and receives a CONT signal, 1227 * then try to make the process runnable again. 1228 */ 1229 if (prop & SA_CONT) { 1230 /* 1231 * If SIGCONT is default (or ignored), we continue the 1232 * process but don't leave the signal in p_siglist, as 1233 * it has no further action. If SIGCONT is held, we 1234 * continue the process and leave the signal in 1235 * p_siglist. If the process catches SIGCONT, let it 1236 * handle the signal itself. 1237 * 1238 * XXX what if the signal is being held blocked? 1239 * 1240 * Token required to interlock kern_wait(). 1241 * Reparenting can also cause a race so we have to 1242 * hold (q). 1243 */ 1244 q = p->p_pptr; 1245 PHOLD(q); 1246 lwkt_gettoken(&q->p_token); 1247 p->p_flags |= P_CONTINUED; 1248 wakeup(q); 1249 if (action == SIG_DFL) 1250 SIGDELSET(p->p_siglist, sig); 1251 proc_unstop(p); 1252 lwkt_reltoken(&q->p_token); 1253 PRELE(q); 1254 if (action == SIG_CATCH) 1255 goto active_process; 1256 goto out; 1257 } 1258 1259 /* 1260 * If the process is stopped and receives another STOP 1261 * signal, we do not need to stop it again. If we did 1262 * the shell could get confused. 1263 * 1264 * However, if the current/preempted lwp is part of the 1265 * process receiving the signal, we need to keep it, 1266 * so that this lwp can stop in issignal() later, as 1267 * we don't want to wait until it reaches userret! 1268 */ 1269 if (prop & SA_STOP) { 1270 if (lwkt_preempted_proc() == NULL || 1271 lwkt_preempted_proc()->lwp_proc != p) 1272 SIGDELSET(p->p_siglist, sig); 1273 } 1274 1275 /* 1276 * Otherwise the process is stopped and it received some 1277 * signal, which does not change its stopped state. When 1278 * the process is continued a wakeup(p) will be issued which 1279 * will wakeup any threads sleeping in tstop(). 1280 */ 1281 if (lp == NULL) { 1282 /* NOTE: returns lp w/ token held */ 1283 lp = find_lwp_for_signal(p, sig); 1284 } 1285 goto out; 1286 1287 /* NOTREACHED */ 1288 } 1289 /* else not stopped */ 1290 active_process: 1291 1292 /* 1293 * Never deliver a lwp-specific signal to a random lwp. 1294 */ 1295 if (lp == NULL) { 1296 /* NOTE: returns lp w/ token held */ 1297 lp = find_lwp_for_signal(p, sig); 1298 if (lp) { 1299 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1300 lwkt_reltoken(&lp->lwp_token); 1301 LWPRELE(lp); 1302 lp = NULL; 1303 } 1304 } 1305 } 1306 1307 /* 1308 * Deliver to the process generically if (1) the signal is being 1309 * sent to any thread or (2) we could not find a thread to deliver 1310 * it to. 1311 */ 1312 if (lp == NULL) { 1313 SIGADDSET(p->p_siglist, sig); 1314 goto out; 1315 } 1316 1317 /* 1318 * Deliver to a specific LWP whether it masks it or not. It will 1319 * not be dispatched if masked but we must still deliver it. 1320 */ 1321 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1322 (p->p_flags & P_TRACED) == 0) { 1323 p->p_nice = NZERO; 1324 } 1325 1326 /* 1327 * If the process receives a STOP signal which indeed needs to 1328 * stop the process, do so. If the process chose to catch the 1329 * signal, it will be treated like any other signal. 1330 */ 1331 if ((prop & SA_STOP) && action == SIG_DFL) { 1332 /* 1333 * If a child holding parent blocked, stopping 1334 * could cause deadlock. Take no action at this 1335 * time. 1336 */ 1337 if (p->p_flags & P_PPWAIT) { 1338 SIGADDSET(p->p_siglist, sig); 1339 goto out; 1340 } 1341 1342 /* 1343 * Do not actually try to manipulate the process, but simply 1344 * stop it. Lwps will stop as soon as they safely can. 1345 * 1346 * Ignore stop if the process is exiting. 1347 */ 1348 if ((p->p_flags & P_WEXIT) == 0) { 1349 p->p_xstat = sig; 1350 proc_stop(p); 1351 } 1352 goto out; 1353 } 1354 1355 /* 1356 * If it is a CONT signal with default action, just ignore it. 1357 */ 1358 if ((prop & SA_CONT) && action == SIG_DFL) 1359 goto out; 1360 1361 /* 1362 * Mark signal pending at this specific thread. 1363 */ 1364 spin_lock(&lp->lwp_spin); 1365 SIGADDSET(lp->lwp_siglist, sig); 1366 spin_unlock(&lp->lwp_spin); 1367 1368 lwp_signotify(lp); 1369 1370 out: 1371 if (lp) { 1372 lwkt_reltoken(&lp->lwp_token); 1373 LWPRELE(lp); 1374 } 1375 lwkt_reltoken(&p->p_token); 1376 PRELE(p); 1377 } 1378 1379 /* 1380 * Notify the LWP that a signal has arrived. The LWP does not have to be 1381 * sleeping on the current cpu. 1382 * 1383 * p->p_token and lp->lwp_token must be held on call. 1384 * 1385 * We can only safely schedule the thread on its current cpu and only if 1386 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1387 * the correct cpu we are properly interlocked, otherwise we could be 1388 * racing other thread transition states (or the lwp is on the user scheduler 1389 * runq but not scheduled) and must not do anything. 1390 * 1391 * Since we hold the lwp token we know the lwp cannot be ripped out from 1392 * under us so we can safely hold it to prevent it from being ripped out 1393 * from under us if we are forced to IPI another cpu to make the local 1394 * checks there. 1395 * 1396 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1397 * which we won't in an IPI so any fixups have to be done here, effectively 1398 * replicating part of what setrunnable() does. 1399 */ 1400 static void 1401 lwp_signotify(struct lwp *lp) 1402 { 1403 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1404 1405 crit_enter(); 1406 if (lp == lwkt_preempted_proc()) { 1407 /* 1408 * lwp is on the current cpu AND it is currently running 1409 * (we preempted it). 1410 */ 1411 signotify(); 1412 } else if (lp->lwp_flags & LWP_SINTR) { 1413 /* 1414 * lwp is sitting in tsleep() with PCATCH set 1415 */ 1416 if (lp->lwp_thread->td_gd == mycpu) { 1417 setrunnable(lp); 1418 } else { 1419 /* 1420 * We can only adjust lwp_stat while we hold the 1421 * lwp_token, and we won't in the IPI function. 1422 */ 1423 LWPHOLD(lp); 1424 if (lp->lwp_stat == LSSTOP) 1425 lp->lwp_stat = LSSLEEP; 1426 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1427 lwp_signotify_remote, lp); 1428 } 1429 } else if (lp->lwp_thread->td_flags & TDF_SINTR) { 1430 /* 1431 * lwp is sitting in lwkt_sleep() with PCATCH set. 1432 */ 1433 if (lp->lwp_thread->td_gd == mycpu) { 1434 setrunnable(lp); 1435 } else { 1436 /* 1437 * We can only adjust lwp_stat while we hold the 1438 * lwp_token, and we won't in the IPI function. 1439 */ 1440 LWPHOLD(lp); 1441 if (lp->lwp_stat == LSSTOP) 1442 lp->lwp_stat = LSSLEEP; 1443 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1444 lwp_signotify_remote, lp); 1445 } 1446 } else { 1447 /* 1448 * Otherwise the lwp is either in some uninterruptable state 1449 * or it is on the userland scheduler's runqueue waiting to 1450 * be scheduled to a cpu. 1451 */ 1452 } 1453 crit_exit(); 1454 } 1455 1456 /* 1457 * This function is called via an IPI so we cannot call setrunnable() here 1458 * (because while we hold the lp we don't own its token, and can't get it 1459 * from an IPI). 1460 * 1461 * We are interlocked by virtue of being on the same cpu as the target. If 1462 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1463 * the target thread. 1464 */ 1465 static void 1466 lwp_signotify_remote(void *arg) 1467 { 1468 struct lwp *lp = arg; 1469 thread_t td = lp->lwp_thread; 1470 1471 if (lp == lwkt_preempted_proc()) { 1472 signotify(); 1473 LWPRELE(lp); 1474 } else if (td->td_gd == mycpu) { 1475 if ((lp->lwp_flags & LWP_SINTR) || 1476 (td->td_flags & TDF_SINTR)) { 1477 lwkt_schedule(td); 1478 } 1479 LWPRELE(lp); 1480 } else { 1481 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1482 /* LWPHOLD() is forwarded to the target cpu */ 1483 } 1484 } 1485 1486 /* 1487 * Caller must hold p->p_token 1488 */ 1489 void 1490 proc_stop(struct proc *p) 1491 { 1492 struct proc *q; 1493 struct lwp *lp; 1494 1495 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1496 1497 /* If somebody raced us, be happy with it */ 1498 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1499 return; 1500 } 1501 p->p_stat = SSTOP; 1502 1503 FOREACH_LWP_IN_PROC(lp, p) { 1504 LWPHOLD(lp); 1505 lwkt_gettoken(&lp->lwp_token); 1506 1507 switch (lp->lwp_stat) { 1508 case LSSTOP: 1509 /* 1510 * Do nothing, we are already counted in 1511 * p_nstopped. 1512 */ 1513 break; 1514 1515 case LSSLEEP: 1516 /* 1517 * We're sleeping, but we will stop before 1518 * returning to userspace, so count us 1519 * as stopped as well. We set LWP_MP_WSTOP 1520 * to signal the lwp that it should not 1521 * increase p_nstopped when reaching tstop(). 1522 * 1523 * LWP_MP_WSTOP is protected by lp->lwp_token. 1524 */ 1525 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1526 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1527 ++p->p_nstopped; 1528 } 1529 break; 1530 1531 case LSRUN: 1532 /* 1533 * We might notify ourself, but that's not 1534 * a problem. 1535 */ 1536 lwp_signotify(lp); 1537 break; 1538 } 1539 lwkt_reltoken(&lp->lwp_token); 1540 LWPRELE(lp); 1541 } 1542 1543 if (p->p_nstopped == p->p_nthreads) { 1544 /* 1545 * Token required to interlock kern_wait(). Reparenting can 1546 * also cause a race so we have to hold (q). 1547 */ 1548 q = p->p_pptr; 1549 PHOLD(q); 1550 lwkt_gettoken(&q->p_token); 1551 p->p_flags &= ~P_WAITED; 1552 wakeup(q); 1553 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1554 ksignal(p->p_pptr, SIGCHLD); 1555 lwkt_reltoken(&q->p_token); 1556 PRELE(q); 1557 } 1558 } 1559 1560 /* 1561 * Caller must hold proc_token 1562 */ 1563 void 1564 proc_unstop(struct proc *p) 1565 { 1566 struct lwp *lp; 1567 1568 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1569 1570 if (p->p_stat != SSTOP) 1571 return; 1572 1573 p->p_stat = SACTIVE; 1574 1575 FOREACH_LWP_IN_PROC(lp, p) { 1576 LWPHOLD(lp); 1577 lwkt_gettoken(&lp->lwp_token); 1578 1579 switch (lp->lwp_stat) { 1580 case LSRUN: 1581 /* 1582 * Uh? Not stopped? Well, I guess that's okay. 1583 */ 1584 if (bootverbose) 1585 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1586 p->p_pid, lp->lwp_tid); 1587 break; 1588 1589 case LSSLEEP: 1590 /* 1591 * Still sleeping. Don't bother waking it up. 1592 * However, if this thread was counted as 1593 * stopped, undo this. 1594 * 1595 * Nevertheless we call setrunnable() so that it 1596 * will wake up in case a signal or timeout arrived 1597 * in the meantime. 1598 * 1599 * LWP_MP_WSTOP is protected by lp->lwp_token. 1600 */ 1601 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1602 atomic_clear_int(&lp->lwp_mpflags, 1603 LWP_MP_WSTOP); 1604 --p->p_nstopped; 1605 } else { 1606 if (bootverbose) 1607 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1608 p->p_pid, lp->lwp_tid); 1609 } 1610 /* FALLTHROUGH */ 1611 1612 case LSSTOP: 1613 /* 1614 * This handles any lwp's waiting in a tsleep with 1615 * SIGCATCH. 1616 */ 1617 lwp_signotify(lp); 1618 break; 1619 1620 } 1621 lwkt_reltoken(&lp->lwp_token); 1622 LWPRELE(lp); 1623 } 1624 1625 /* 1626 * This handles any lwp's waiting in tstop(). We have interlocked 1627 * the setting of p_stat by acquiring and releasing each lpw's 1628 * token. 1629 */ 1630 wakeup(p); 1631 } 1632 1633 /* 1634 * No requirements. 1635 */ 1636 static int 1637 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1638 { 1639 sigset_t savedmask, set; 1640 struct proc *p = curproc; 1641 struct lwp *lp = curthread->td_lwp; 1642 int error, sig, hz, timevalid = 0; 1643 struct timespec rts, ets, ts; 1644 struct timeval tv; 1645 1646 error = 0; 1647 sig = 0; 1648 ets.tv_sec = 0; /* silence compiler warning */ 1649 ets.tv_nsec = 0; /* silence compiler warning */ 1650 SIG_CANTMASK(waitset); 1651 savedmask = lp->lwp_sigmask; 1652 1653 if (timeout) { 1654 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1655 timeout->tv_nsec < 1000000000) { 1656 timevalid = 1; 1657 getnanouptime(&rts); 1658 ets = rts; 1659 timespecadd(&ets, timeout); 1660 } 1661 } 1662 1663 for (;;) { 1664 set = lwp_sigpend(lp); 1665 SIGSETAND(set, waitset); 1666 if ((sig = sig_ffs(&set)) != 0) { 1667 SIGFILLSET(lp->lwp_sigmask); 1668 SIGDELSET(lp->lwp_sigmask, sig); 1669 SIG_CANTMASK(lp->lwp_sigmask); 1670 sig = issignal(lp, 1); 1671 /* 1672 * It may be a STOP signal, in the case, issignal 1673 * returns 0, because we may stop there, and new 1674 * signal can come in, we should restart if we got 1675 * nothing. 1676 */ 1677 if (sig == 0) 1678 continue; 1679 else 1680 break; 1681 } 1682 1683 /* 1684 * Previous checking got nothing, and we retried but still 1685 * got nothing, we should return the error status. 1686 */ 1687 if (error) 1688 break; 1689 1690 /* 1691 * POSIX says this must be checked after looking for pending 1692 * signals. 1693 */ 1694 if (timeout) { 1695 if (timevalid == 0) { 1696 error = EINVAL; 1697 break; 1698 } 1699 getnanouptime(&rts); 1700 if (timespeccmp(&rts, &ets, >=)) { 1701 error = EAGAIN; 1702 break; 1703 } 1704 ts = ets; 1705 timespecsub(&ts, &rts); 1706 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1707 hz = tvtohz_high(&tv); 1708 } else { 1709 hz = 0; 1710 } 1711 1712 lp->lwp_sigmask = savedmask; 1713 SIGSETNAND(lp->lwp_sigmask, waitset); 1714 /* 1715 * We won't ever be woken up. Instead, our sleep will 1716 * be broken in lwpsignal(). 1717 */ 1718 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1719 if (timeout) { 1720 if (error == ERESTART) { 1721 /* can not restart a timeout wait. */ 1722 error = EINTR; 1723 } else if (error == EAGAIN) { 1724 /* will calculate timeout by ourself. */ 1725 error = 0; 1726 } 1727 } 1728 /* Retry ... */ 1729 } 1730 1731 lp->lwp_sigmask = savedmask; 1732 if (sig) { 1733 error = 0; 1734 bzero(info, sizeof(*info)); 1735 info->si_signo = sig; 1736 spin_lock(&lp->lwp_spin); 1737 lwp_delsig(lp, sig); /* take the signal! */ 1738 spin_unlock(&lp->lwp_spin); 1739 1740 if (sig == SIGKILL) { 1741 sigexit(lp, sig); 1742 /* NOT REACHED */ 1743 } 1744 } 1745 1746 return (error); 1747 } 1748 1749 /* 1750 * MPALMOSTSAFE 1751 */ 1752 int 1753 sys_sigtimedwait(struct sigtimedwait_args *uap) 1754 { 1755 struct timespec ts; 1756 struct timespec *timeout; 1757 sigset_t set; 1758 siginfo_t info; 1759 int error; 1760 1761 if (uap->timeout) { 1762 error = copyin(uap->timeout, &ts, sizeof(ts)); 1763 if (error) 1764 return (error); 1765 timeout = &ts; 1766 } else { 1767 timeout = NULL; 1768 } 1769 error = copyin(uap->set, &set, sizeof(set)); 1770 if (error) 1771 return (error); 1772 error = kern_sigtimedwait(set, &info, timeout); 1773 if (error) 1774 return (error); 1775 if (uap->info) 1776 error = copyout(&info, uap->info, sizeof(info)); 1777 /* Repost if we got an error. */ 1778 /* 1779 * XXX lwp 1780 * 1781 * This could transform a thread-specific signal to another 1782 * thread / process pending signal. 1783 */ 1784 if (error) { 1785 ksignal(curproc, info.si_signo); 1786 } else { 1787 uap->sysmsg_result = info.si_signo; 1788 } 1789 return (error); 1790 } 1791 1792 /* 1793 * MPALMOSTSAFE 1794 */ 1795 int 1796 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1797 { 1798 siginfo_t info; 1799 sigset_t set; 1800 int error; 1801 1802 error = copyin(uap->set, &set, sizeof(set)); 1803 if (error) 1804 return (error); 1805 error = kern_sigtimedwait(set, &info, NULL); 1806 if (error) 1807 return (error); 1808 if (uap->info) 1809 error = copyout(&info, uap->info, sizeof(info)); 1810 /* Repost if we got an error. */ 1811 /* 1812 * XXX lwp 1813 * 1814 * This could transform a thread-specific signal to another 1815 * thread / process pending signal. 1816 */ 1817 if (error) { 1818 ksignal(curproc, info.si_signo); 1819 } else { 1820 uap->sysmsg_result = info.si_signo; 1821 } 1822 return (error); 1823 } 1824 1825 /* 1826 * If the current process has received a signal that would interrupt a 1827 * system call, return EINTR or ERESTART as appropriate. 1828 */ 1829 int 1830 iscaught(struct lwp *lp) 1831 { 1832 struct proc *p = lp->lwp_proc; 1833 int sig; 1834 1835 if (p) { 1836 if ((sig = CURSIG(lp)) != 0) { 1837 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1838 return (EINTR); 1839 return (ERESTART); 1840 } 1841 } 1842 return(EWOULDBLOCK); 1843 } 1844 1845 /* 1846 * If the current process has received a signal (should be caught or cause 1847 * termination, should interrupt current syscall), return the signal number. 1848 * Stop signals with default action are processed immediately, then cleared; 1849 * they aren't returned. This is checked after each entry to the system for 1850 * a syscall or trap (though this can usually be done without calling issignal 1851 * by checking the pending signal masks in the CURSIG macro). 1852 * 1853 * This routine is called via CURSIG/__cursig. We will acquire and release 1854 * p->p_token but if the caller needs to interlock the test the caller must 1855 * also hold p->p_token. 1856 * 1857 * while (sig = CURSIG(curproc)) 1858 * postsig(sig); 1859 * 1860 * MPSAFE 1861 */ 1862 int 1863 issignal(struct lwp *lp, int maytrace) 1864 { 1865 struct proc *p = lp->lwp_proc; 1866 sigset_t mask; 1867 int sig, prop; 1868 1869 lwkt_gettoken(&p->p_token); 1870 1871 for (;;) { 1872 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1873 1874 /* 1875 * If this process is supposed to stop, stop this thread. 1876 */ 1877 if (p->p_stat == SSTOP) 1878 tstop(); 1879 1880 mask = lwp_sigpend(lp); 1881 SIGSETNAND(mask, lp->lwp_sigmask); 1882 if (p->p_flags & P_PPWAIT) 1883 SIG_STOPSIGMASK(mask); 1884 if (SIGISEMPTY(mask)) { /* no signal to send */ 1885 lwkt_reltoken(&p->p_token); 1886 return (0); 1887 } 1888 sig = sig_ffs(&mask); 1889 1890 STOPEVENT(p, S_SIG, sig); 1891 1892 /* 1893 * We should see pending but ignored signals 1894 * only if P_TRACED was on when they were posted. 1895 */ 1896 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1897 spin_lock(&lp->lwp_spin); 1898 lwp_delsig(lp, sig); 1899 spin_unlock(&lp->lwp_spin); 1900 continue; 1901 } 1902 if (maytrace && 1903 (p->p_flags & P_TRACED) && 1904 (p->p_flags & P_PPWAIT) == 0) { 1905 /* 1906 * If traced, always stop, and stay stopped until 1907 * released by the parent. 1908 * 1909 * NOTE: SSTOP may get cleared during the loop, 1910 * but we do not re-notify the parent if we have 1911 * to loop several times waiting for the parent 1912 * to let us continue. 1913 * 1914 * XXX not sure if this is still true 1915 */ 1916 p->p_xstat = sig; 1917 proc_stop(p); 1918 do { 1919 tstop(); 1920 } while (!trace_req(p) && (p->p_flags & P_TRACED)); 1921 1922 /* 1923 * If parent wants us to take the signal, 1924 * then it will leave it in p->p_xstat; 1925 * otherwise we just look for signals again. 1926 */ 1927 spin_lock(&lp->lwp_spin); 1928 lwp_delsig(lp, sig); /* clear old signal */ 1929 spin_unlock(&lp->lwp_spin); 1930 sig = p->p_xstat; 1931 if (sig == 0) 1932 continue; 1933 1934 /* 1935 * Put the new signal into p_siglist. If the 1936 * signal is being masked, look for other signals. 1937 * 1938 * XXX lwp might need a call to ksignal() 1939 */ 1940 SIGADDSET(p->p_siglist, sig); 1941 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1942 continue; 1943 1944 /* 1945 * If the traced bit got turned off, go back up 1946 * to the top to rescan signals. This ensures 1947 * that p_sig* and ps_sigact are consistent. 1948 */ 1949 if ((p->p_flags & P_TRACED) == 0) 1950 continue; 1951 } 1952 1953 prop = sigprop(sig); 1954 1955 /* 1956 * Decide whether the signal should be returned. 1957 * Return the signal's number, or fall through 1958 * to clear it from the pending mask. 1959 */ 1960 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1961 case (intptr_t)SIG_DFL: 1962 /* 1963 * Don't take default actions on system processes. 1964 */ 1965 if (p->p_pid <= 1) { 1966 #ifdef DIAGNOSTIC 1967 /* 1968 * Are you sure you want to ignore SIGSEGV 1969 * in init? XXX 1970 */ 1971 kprintf("Process (pid %lu) got signal %d\n", 1972 (u_long)p->p_pid, sig); 1973 #endif 1974 break; /* == ignore */ 1975 } 1976 1977 /* 1978 * Handle the in-kernel checkpoint action 1979 */ 1980 if (prop & SA_CKPT) { 1981 checkpoint_signal_handler(lp); 1982 break; 1983 } 1984 1985 /* 1986 * If there is a pending stop signal to process 1987 * with default action, stop here, 1988 * then clear the signal. However, 1989 * if process is member of an orphaned 1990 * process group, ignore tty stop signals. 1991 */ 1992 if (prop & SA_STOP) { 1993 if (p->p_flags & P_TRACED || 1994 (p->p_pgrp->pg_jobc == 0 && 1995 prop & SA_TTYSTOP)) 1996 break; /* == ignore */ 1997 if ((p->p_flags & P_WEXIT) == 0) { 1998 p->p_xstat = sig; 1999 proc_stop(p); 2000 tstop(); 2001 } 2002 break; 2003 } else if (prop & SA_IGNORE) { 2004 /* 2005 * Except for SIGCONT, shouldn't get here. 2006 * Default action is to ignore; drop it. 2007 */ 2008 break; /* == ignore */ 2009 } else { 2010 lwkt_reltoken(&p->p_token); 2011 return (sig); 2012 } 2013 2014 /*NOTREACHED*/ 2015 2016 case (intptr_t)SIG_IGN: 2017 /* 2018 * Masking above should prevent us ever trying 2019 * to take action on an ignored signal other 2020 * than SIGCONT, unless process is traced. 2021 */ 2022 if ((prop & SA_CONT) == 0 && 2023 (p->p_flags & P_TRACED) == 0) 2024 kprintf("issignal\n"); 2025 break; /* == ignore */ 2026 2027 default: 2028 /* 2029 * This signal has an action, let 2030 * postsig() process it. 2031 */ 2032 lwkt_reltoken(&p->p_token); 2033 return (sig); 2034 } 2035 spin_lock(&lp->lwp_spin); 2036 lwp_delsig(lp, sig); /* take the signal! */ 2037 spin_unlock(&lp->lwp_spin); 2038 } 2039 /* NOTREACHED */ 2040 } 2041 2042 /* 2043 * Take the action for the specified signal 2044 * from the current set of pending signals. 2045 * 2046 * Caller must hold p->p_token 2047 */ 2048 void 2049 postsig(int sig) 2050 { 2051 struct lwp *lp = curthread->td_lwp; 2052 struct proc *p = lp->lwp_proc; 2053 struct sigacts *ps = p->p_sigacts; 2054 sig_t action; 2055 sigset_t returnmask; 2056 int code; 2057 2058 KASSERT(sig != 0, ("postsig")); 2059 2060 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2061 2062 /* 2063 * If we are a virtual kernel running an emulated user process 2064 * context, switch back to the virtual kernel context before 2065 * trying to post the signal. 2066 */ 2067 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2068 struct trapframe *tf = lp->lwp_md.md_regs; 2069 tf->tf_trapno = 0; 2070 vkernel_trap(lp, tf); 2071 } 2072 2073 spin_lock(&lp->lwp_spin); 2074 lwp_delsig(lp, sig); 2075 spin_unlock(&lp->lwp_spin); 2076 action = ps->ps_sigact[_SIG_IDX(sig)]; 2077 #ifdef KTRACE 2078 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2079 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2080 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2081 #endif 2082 STOPEVENT(p, S_SIG, sig); 2083 2084 if (action == SIG_DFL) { 2085 /* 2086 * Default action, where the default is to kill 2087 * the process. (Other cases were ignored above.) 2088 */ 2089 sigexit(lp, sig); 2090 /* NOTREACHED */ 2091 } else { 2092 /* 2093 * If we get here, the signal must be caught. 2094 */ 2095 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2096 ("postsig action")); 2097 2098 /* 2099 * Reset the signal handler if asked to 2100 */ 2101 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2102 /* 2103 * See kern_sigaction() for origin of this code. 2104 */ 2105 SIGDELSET(p->p_sigcatch, sig); 2106 if (sig != SIGCONT && 2107 sigprop(sig) & SA_IGNORE) 2108 SIGADDSET(p->p_sigignore, sig); 2109 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2110 } 2111 2112 /* 2113 * Set the signal mask and calculate the mask to restore 2114 * when the signal function returns. 2115 * 2116 * Special case: user has done a sigsuspend. Here the 2117 * current mask is not of interest, but rather the 2118 * mask from before the sigsuspend is what we want 2119 * restored after the signal processing is completed. 2120 */ 2121 if (lp->lwp_flags & LWP_OLDMASK) { 2122 returnmask = lp->lwp_oldsigmask; 2123 lp->lwp_flags &= ~LWP_OLDMASK; 2124 } else { 2125 returnmask = lp->lwp_sigmask; 2126 } 2127 2128 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2129 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2130 SIGADDSET(lp->lwp_sigmask, sig); 2131 2132 lp->lwp_ru.ru_nsignals++; 2133 if (lp->lwp_sig != sig) { 2134 code = 0; 2135 } else { 2136 code = lp->lwp_code; 2137 lp->lwp_code = 0; 2138 lp->lwp_sig = 0; 2139 } 2140 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2141 } 2142 } 2143 2144 /* 2145 * Kill the current process for stated reason. 2146 */ 2147 void 2148 killproc(struct proc *p, char *why) 2149 { 2150 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2151 p->p_pid, p->p_comm, 2152 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2153 ksignal(p, SIGKILL); 2154 } 2155 2156 /* 2157 * Force the current process to exit with the specified signal, dumping core 2158 * if appropriate. We bypass the normal tests for masked and caught signals, 2159 * allowing unrecoverable failures to terminate the process without changing 2160 * signal state. Mark the accounting record with the signal termination. 2161 * If dumping core, save the signal number for the debugger. Calls exit and 2162 * does not return. 2163 * 2164 * This routine does not return. 2165 */ 2166 void 2167 sigexit(struct lwp *lp, int sig) 2168 { 2169 struct proc *p = lp->lwp_proc; 2170 2171 lwkt_gettoken(&p->p_token); 2172 p->p_acflag |= AXSIG; 2173 if (sigprop(sig) & SA_CORE) { 2174 lp->lwp_sig = sig; 2175 /* 2176 * Log signals which would cause core dumps 2177 * (Log as LOG_INFO to appease those who don't want 2178 * these messages.) 2179 * XXX : Todo, as well as euid, write out ruid too 2180 */ 2181 if (coredump(lp, sig) == 0) 2182 sig |= WCOREFLAG; 2183 if (kern_logsigexit) 2184 log(LOG_INFO, 2185 "pid %d (%s), uid %d: exited on signal %d%s\n", 2186 p->p_pid, p->p_comm, 2187 p->p_ucred ? p->p_ucred->cr_uid : -1, 2188 sig &~ WCOREFLAG, 2189 sig & WCOREFLAG ? " (core dumped)" : ""); 2190 } 2191 lwkt_reltoken(&p->p_token); 2192 exit1(W_EXITCODE(0, sig)); 2193 /* NOTREACHED */ 2194 } 2195 2196 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2197 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2198 sizeof(corefilename), "process corefile name format string"); 2199 2200 /* 2201 * expand_name(name, uid, pid) 2202 * Expand the name described in corefilename, using name, uid, and pid. 2203 * corefilename is a kprintf-like string, with three format specifiers: 2204 * %N name of process ("name") 2205 * %P process id (pid) 2206 * %U user id (uid) 2207 * For example, "%N.core" is the default; they can be disabled completely 2208 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2209 * This is controlled by the sysctl variable kern.corefile (see above). 2210 */ 2211 2212 static char * 2213 expand_name(const char *name, uid_t uid, pid_t pid) 2214 { 2215 char *temp; 2216 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2217 int i, n; 2218 char *format = corefilename; 2219 size_t namelen; 2220 2221 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2222 if (temp == NULL) 2223 return NULL; 2224 namelen = strlen(name); 2225 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2226 int l; 2227 switch (format[i]) { 2228 case '%': /* Format character */ 2229 i++; 2230 switch (format[i]) { 2231 case '%': 2232 temp[n++] = '%'; 2233 break; 2234 case 'N': /* process name */ 2235 if ((n + namelen) > MAXPATHLEN) { 2236 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2237 pid, name, uid, temp, name); 2238 kfree(temp, M_TEMP); 2239 return NULL; 2240 } 2241 memcpy(temp+n, name, namelen); 2242 n += namelen; 2243 break; 2244 case 'P': /* process id */ 2245 l = ksprintf(buf, "%u", pid); 2246 if ((n + l) > MAXPATHLEN) { 2247 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2248 pid, name, uid, temp, name); 2249 kfree(temp, M_TEMP); 2250 return NULL; 2251 } 2252 memcpy(temp+n, buf, l); 2253 n += l; 2254 break; 2255 case 'U': /* user id */ 2256 l = ksprintf(buf, "%u", uid); 2257 if ((n + l) > MAXPATHLEN) { 2258 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2259 pid, name, uid, temp, name); 2260 kfree(temp, M_TEMP); 2261 return NULL; 2262 } 2263 memcpy(temp+n, buf, l); 2264 n += l; 2265 break; 2266 default: 2267 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2268 } 2269 break; 2270 default: 2271 temp[n++] = format[i]; 2272 } 2273 } 2274 temp[n] = '\0'; 2275 return temp; 2276 } 2277 2278 /* 2279 * Dump a process' core. The main routine does some 2280 * policy checking, and creates the name of the coredump; 2281 * then it passes on a vnode and a size limit to the process-specific 2282 * coredump routine if there is one; if there _is not_ one, it returns 2283 * ENOSYS; otherwise it returns the error from the process-specific routine. 2284 * 2285 * The parameter `lp' is the lwp which triggered the coredump. 2286 */ 2287 2288 static int 2289 coredump(struct lwp *lp, int sig) 2290 { 2291 struct proc *p = lp->lwp_proc; 2292 struct vnode *vp; 2293 struct ucred *cred = p->p_ucred; 2294 struct flock lf; 2295 struct nlookupdata nd; 2296 struct vattr vattr; 2297 int error, error1; 2298 char *name; /* name of corefile */ 2299 off_t limit; 2300 2301 STOPEVENT(p, S_CORE, 0); 2302 2303 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2304 return (EFAULT); 2305 2306 /* 2307 * Note that the bulk of limit checking is done after 2308 * the corefile is created. The exception is if the limit 2309 * for corefiles is 0, in which case we don't bother 2310 * creating the corefile at all. This layout means that 2311 * a corefile is truncated instead of not being created, 2312 * if it is larger than the limit. 2313 */ 2314 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2315 if (limit == 0) 2316 return EFBIG; 2317 2318 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2319 if (name == NULL) 2320 return (EINVAL); 2321 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2322 if (error == 0) 2323 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2324 kfree(name, M_TEMP); 2325 if (error) { 2326 nlookup_done(&nd); 2327 return (error); 2328 } 2329 vp = nd.nl_open_vp; 2330 nd.nl_open_vp = NULL; 2331 nlookup_done(&nd); 2332 2333 vn_unlock(vp); 2334 lf.l_whence = SEEK_SET; 2335 lf.l_start = 0; 2336 lf.l_len = 0; 2337 lf.l_type = F_WRLCK; 2338 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2339 if (error) 2340 goto out2; 2341 2342 /* Don't dump to non-regular files or files with links. */ 2343 if (vp->v_type != VREG || 2344 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2345 error = EFAULT; 2346 goto out1; 2347 } 2348 2349 /* Don't dump to files current user does not own */ 2350 if (vattr.va_uid != p->p_ucred->cr_uid) { 2351 error = EFAULT; 2352 goto out1; 2353 } 2354 2355 VATTR_NULL(&vattr); 2356 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2357 vattr.va_size = 0; 2358 VOP_SETATTR(vp, &vattr, cred); 2359 p->p_acflag |= ACORE; 2360 vn_unlock(vp); 2361 2362 error = p->p_sysent->sv_coredump ? 2363 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2364 2365 out1: 2366 lf.l_type = F_UNLCK; 2367 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2368 out2: 2369 error1 = vn_close(vp, FWRITE); 2370 if (error == 0) 2371 error = error1; 2372 return (error); 2373 } 2374 2375 /* 2376 * Nonexistent system call-- signal process (may want to handle it). 2377 * Flag error in case process won't see signal immediately (blocked or ignored). 2378 * 2379 * MPALMOSTSAFE 2380 */ 2381 /* ARGSUSED */ 2382 int 2383 sys_nosys(struct nosys_args *args) 2384 { 2385 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2386 return (EINVAL); 2387 } 2388 2389 /* 2390 * Send a SIGIO or SIGURG signal to a process or process group using 2391 * stored credentials rather than those of the current process. 2392 */ 2393 void 2394 pgsigio(struct sigio *sigio, int sig, int checkctty) 2395 { 2396 if (sigio == NULL) 2397 return; 2398 2399 if (sigio->sio_pgid > 0) { 2400 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2401 sigio->sio_proc)) 2402 ksignal(sigio->sio_proc, sig); 2403 } else if (sigio->sio_pgid < 0) { 2404 struct proc *p; 2405 struct pgrp *pg = sigio->sio_pgrp; 2406 2407 /* 2408 * Must interlock all signals against fork 2409 */ 2410 pgref(pg); 2411 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2412 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2413 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2414 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2415 ksignal(p, sig); 2416 } 2417 lockmgr(&pg->pg_lock, LK_RELEASE); 2418 pgrel(pg); 2419 } 2420 } 2421 2422 static int 2423 filt_sigattach(struct knote *kn) 2424 { 2425 struct proc *p = curproc; 2426 2427 kn->kn_ptr.p_proc = p; 2428 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2429 2430 /* XXX lock the proc here while adding to the list? */ 2431 knote_insert(&p->p_klist, kn); 2432 2433 return (0); 2434 } 2435 2436 static void 2437 filt_sigdetach(struct knote *kn) 2438 { 2439 struct proc *p = kn->kn_ptr.p_proc; 2440 2441 knote_remove(&p->p_klist, kn); 2442 } 2443 2444 /* 2445 * signal knotes are shared with proc knotes, so we apply a mask to 2446 * the hint in order to differentiate them from process hints. This 2447 * could be avoided by using a signal-specific knote list, but probably 2448 * isn't worth the trouble. 2449 */ 2450 static int 2451 filt_signal(struct knote *kn, long hint) 2452 { 2453 if (hint & NOTE_SIGNAL) { 2454 hint &= ~NOTE_SIGNAL; 2455 2456 if (kn->kn_id == hint) 2457 kn->kn_data++; 2458 } 2459 return (kn->kn_data != 0); 2460 } 2461