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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. 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 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/sysproto.h> 48 #include <sys/signalvar.h> 49 #include <sys/resourcevar.h> 50 #include <sys/vnode.h> 51 #include <sys/event.h> 52 #include <sys/proc.h> 53 #include <sys/nlookup.h> 54 #include <sys/pioctl.h> 55 #include <sys/acct.h> 56 #include <sys/fcntl.h> 57 #include <sys/lock.h> 58 #include <sys/wait.h> 59 #include <sys/ktrace.h> 60 #include <sys/syslog.h> 61 #include <sys/stat.h> 62 #include <sys/sysent.h> 63 #include <sys/sysctl.h> 64 #include <sys/malloc.h> 65 #include <sys/interrupt.h> 66 #include <sys/unistd.h> 67 #include <sys/kern_syscall.h> 68 #include <sys/vkernel.h> 69 70 #include <sys/signal2.h> 71 #include <sys/thread2.h> 72 #include <sys/spinlock2.h> 73 74 #include <machine/cpu.h> 75 #include <machine/smp.h> 76 77 static int coredump(struct lwp *, int); 78 static char *expand_name(const char *, uid_t, pid_t); 79 static int dokillpg(int sig, int pgid, int all); 80 static int sig_ffs(sigset_t *set); 81 static int sigprop(int sig); 82 static void lwp_signotify(struct lwp *lp); 83 #ifdef SMP 84 static void lwp_signotify_remote(void *arg); 85 #endif 86 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 87 struct timespec *timeout); 88 89 static int filt_sigattach(struct knote *kn); 90 static void filt_sigdetach(struct knote *kn); 91 static int filt_signal(struct knote *kn, long hint); 92 93 struct filterops sig_filtops = 94 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 95 96 static int kern_logsigexit = 1; 97 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 98 &kern_logsigexit, 0, 99 "Log processes quitting on abnormal signals to syslog(3)"); 100 101 /* 102 * Can process p, with pcred pc, send the signal sig to process q? 103 */ 104 #define CANSIGNAL(q, sig) \ 105 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 106 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 107 108 /* 109 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 110 */ 111 #define CANSIGIO(ruid, uc, q) \ 112 ((uc)->cr_uid == 0 || \ 113 (ruid) == (q)->p_ucred->cr_ruid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 115 (ruid) == (q)->p_ucred->cr_uid || \ 116 (uc)->cr_uid == (q)->p_ucred->cr_uid) 117 118 int sugid_coredump; 119 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 120 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 121 122 static int do_coredump = 1; 123 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 124 &do_coredump, 0, "Enable/Disable coredumps"); 125 126 /* 127 * Signal properties and actions. 128 * The array below categorizes the signals and their default actions 129 * according to the following properties: 130 */ 131 #define SA_KILL 0x01 /* terminates process by default */ 132 #define SA_CORE 0x02 /* ditto and coredumps */ 133 #define SA_STOP 0x04 /* suspend process */ 134 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 135 #define SA_IGNORE 0x10 /* ignore by default */ 136 #define SA_CONT 0x20 /* continue if suspended */ 137 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 138 #define SA_CKPT 0x80 /* checkpoint process */ 139 140 141 static int sigproptbl[NSIG] = { 142 SA_KILL, /* SIGHUP */ 143 SA_KILL, /* SIGINT */ 144 SA_KILL|SA_CORE, /* SIGQUIT */ 145 SA_KILL|SA_CORE, /* SIGILL */ 146 SA_KILL|SA_CORE, /* SIGTRAP */ 147 SA_KILL|SA_CORE, /* SIGABRT */ 148 SA_KILL|SA_CORE, /* SIGEMT */ 149 SA_KILL|SA_CORE, /* SIGFPE */ 150 SA_KILL, /* SIGKILL */ 151 SA_KILL|SA_CORE, /* SIGBUS */ 152 SA_KILL|SA_CORE, /* SIGSEGV */ 153 SA_KILL|SA_CORE, /* SIGSYS */ 154 SA_KILL, /* SIGPIPE */ 155 SA_KILL, /* SIGALRM */ 156 SA_KILL, /* SIGTERM */ 157 SA_IGNORE, /* SIGURG */ 158 SA_STOP, /* SIGSTOP */ 159 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 160 SA_IGNORE|SA_CONT, /* SIGCONT */ 161 SA_IGNORE, /* SIGCHLD */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 163 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 164 SA_IGNORE, /* SIGIO */ 165 SA_KILL, /* SIGXCPU */ 166 SA_KILL, /* SIGXFSZ */ 167 SA_KILL, /* SIGVTALRM */ 168 SA_KILL, /* SIGPROF */ 169 SA_IGNORE, /* SIGWINCH */ 170 SA_IGNORE, /* SIGINFO */ 171 SA_KILL, /* SIGUSR1 */ 172 SA_KILL, /* SIGUSR2 */ 173 SA_IGNORE, /* SIGTHR */ 174 SA_CKPT, /* SIGCKPT */ 175 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 SA_IGNORE, 206 207 }; 208 209 static __inline int 210 sigprop(int sig) 211 { 212 213 if (sig > 0 && sig < NSIG) 214 return (sigproptbl[_SIG_IDX(sig)]); 215 return (0); 216 } 217 218 static __inline int 219 sig_ffs(sigset_t *set) 220 { 221 int i; 222 223 for (i = 0; i < _SIG_WORDS; i++) 224 if (set->__bits[i]) 225 return (ffs(set->__bits[i]) + (i * 32)); 226 return (0); 227 } 228 229 /* 230 * No requirements. 231 */ 232 int 233 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 234 { 235 struct thread *td = curthread; 236 struct proc *p = td->td_proc; 237 struct lwp *lp; 238 struct sigacts *ps = p->p_sigacts; 239 240 if (sig <= 0 || sig > _SIG_MAXSIG) 241 return (EINVAL); 242 243 lwkt_gettoken(&p->p_token); 244 245 if (oact) { 246 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 247 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 248 oact->sa_flags = 0; 249 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 250 oact->sa_flags |= SA_ONSTACK; 251 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 252 oact->sa_flags |= SA_RESTART; 253 if (SIGISMEMBER(ps->ps_sigreset, sig)) 254 oact->sa_flags |= SA_RESETHAND; 255 if (SIGISMEMBER(ps->ps_signodefer, sig)) 256 oact->sa_flags |= SA_NODEFER; 257 if (SIGISMEMBER(ps->ps_siginfo, sig)) 258 oact->sa_flags |= SA_SIGINFO; 259 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 260 oact->sa_flags |= SA_NOCLDSTOP; 261 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 262 oact->sa_flags |= SA_NOCLDWAIT; 263 } 264 if (act) { 265 /* 266 * Check for invalid requests. KILL and STOP cannot be 267 * caught. 268 */ 269 if (sig == SIGKILL || sig == SIGSTOP) { 270 if (act->sa_handler != SIG_DFL) { 271 lwkt_reltoken(&p->p_token); 272 return (EINVAL); 273 } 274 } 275 276 /* 277 * Change setting atomically. 278 */ 279 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 280 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 281 if (act->sa_flags & SA_SIGINFO) { 282 ps->ps_sigact[_SIG_IDX(sig)] = 283 (__sighandler_t *)act->sa_sigaction; 284 SIGADDSET(ps->ps_siginfo, sig); 285 } else { 286 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 287 SIGDELSET(ps->ps_siginfo, sig); 288 } 289 if (!(act->sa_flags & SA_RESTART)) 290 SIGADDSET(ps->ps_sigintr, sig); 291 else 292 SIGDELSET(ps->ps_sigintr, sig); 293 if (act->sa_flags & SA_ONSTACK) 294 SIGADDSET(ps->ps_sigonstack, sig); 295 else 296 SIGDELSET(ps->ps_sigonstack, sig); 297 if (act->sa_flags & SA_RESETHAND) 298 SIGADDSET(ps->ps_sigreset, sig); 299 else 300 SIGDELSET(ps->ps_sigreset, sig); 301 if (act->sa_flags & SA_NODEFER) 302 SIGADDSET(ps->ps_signodefer, sig); 303 else 304 SIGDELSET(ps->ps_signodefer, sig); 305 if (sig == SIGCHLD) { 306 if (act->sa_flags & SA_NOCLDSTOP) 307 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 308 else 309 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 310 if (act->sa_flags & SA_NOCLDWAIT) { 311 /* 312 * Paranoia: since SA_NOCLDWAIT is implemented 313 * by reparenting the dying child to PID 1 (and 314 * trust it to reap the zombie), PID 1 itself 315 * is forbidden to set SA_NOCLDWAIT. 316 */ 317 if (p->p_pid == 1) 318 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 319 else 320 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 321 } else { 322 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 323 } 324 } 325 /* 326 * Set bit in p_sigignore for signals that are set to SIG_IGN, 327 * and for signals set to SIG_DFL where the default is to 328 * ignore. However, don't put SIGCONT in p_sigignore, as we 329 * have to restart the process. 330 * 331 * Also remove the signal from the process and lwp signal 332 * list. 333 */ 334 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 335 (sigprop(sig) & SA_IGNORE && 336 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 337 SIGDELSET(p->p_siglist, sig); 338 FOREACH_LWP_IN_PROC(lp, p) { 339 spin_lock(&lp->lwp_spin); 340 SIGDELSET(lp->lwp_siglist, sig); 341 spin_unlock(&lp->lwp_spin); 342 } 343 if (sig != SIGCONT) { 344 /* easier in ksignal */ 345 SIGADDSET(p->p_sigignore, sig); 346 } 347 SIGDELSET(p->p_sigcatch, sig); 348 } else { 349 SIGDELSET(p->p_sigignore, sig); 350 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 351 SIGDELSET(p->p_sigcatch, sig); 352 else 353 SIGADDSET(p->p_sigcatch, sig); 354 } 355 } 356 lwkt_reltoken(&p->p_token); 357 return (0); 358 } 359 360 int 361 sys_sigaction(struct sigaction_args *uap) 362 { 363 struct sigaction act, oact; 364 struct sigaction *actp, *oactp; 365 int error; 366 367 actp = (uap->act != NULL) ? &act : NULL; 368 oactp = (uap->oact != NULL) ? &oact : NULL; 369 if (actp) { 370 error = copyin(uap->act, actp, sizeof(act)); 371 if (error) 372 return (error); 373 } 374 error = kern_sigaction(uap->sig, actp, oactp); 375 if (oactp && !error) { 376 error = copyout(oactp, uap->oact, sizeof(oact)); 377 } 378 return (error); 379 } 380 381 /* 382 * Initialize signal state for process 0; 383 * set to ignore signals that are ignored by default. 384 */ 385 void 386 siginit(struct proc *p) 387 { 388 int i; 389 390 for (i = 1; i <= NSIG; i++) 391 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 392 SIGADDSET(p->p_sigignore, i); 393 } 394 395 /* 396 * Reset signals for an exec of the specified process. 397 */ 398 void 399 execsigs(struct proc *p) 400 { 401 struct sigacts *ps = p->p_sigacts; 402 struct lwp *lp; 403 int sig; 404 405 lp = ONLY_LWP_IN_PROC(p); 406 407 /* 408 * Reset caught signals. Held signals remain held 409 * through p_sigmask (unless they were caught, 410 * and are now ignored by default). 411 */ 412 while (SIGNOTEMPTY(p->p_sigcatch)) { 413 sig = sig_ffs(&p->p_sigcatch); 414 SIGDELSET(p->p_sigcatch, sig); 415 if (sigprop(sig) & SA_IGNORE) { 416 if (sig != SIGCONT) 417 SIGADDSET(p->p_sigignore, sig); 418 SIGDELSET(p->p_siglist, sig); 419 /* don't need spinlock */ 420 SIGDELSET(lp->lwp_siglist, sig); 421 } 422 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 423 } 424 425 /* 426 * Reset stack state to the user stack. 427 * Clear set of signals caught on the signal stack. 428 */ 429 lp->lwp_sigstk.ss_flags = SS_DISABLE; 430 lp->lwp_sigstk.ss_size = 0; 431 lp->lwp_sigstk.ss_sp = 0; 432 lp->lwp_flags &= ~LWP_ALTSTACK; 433 /* 434 * Reset no zombies if child dies flag as Solaris does. 435 */ 436 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 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 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 610 return (EINVAL); 611 lp->lwp_flags &= ~LWP_ALTSTACK; 612 lp->lwp_sigstk.ss_flags = ss->ss_flags; 613 } else { 614 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 615 return (ENOMEM); 616 lp->lwp_flags |= LWP_ALTSTACK; 617 lp->lwp_sigstk = *ss; 618 } 619 } 620 621 return (0); 622 } 623 624 /* 625 * MPSAFE 626 */ 627 int 628 sys_sigaltstack(struct sigaltstack_args *uap) 629 { 630 stack_t ss, oss; 631 int error; 632 633 if (uap->ss) { 634 error = copyin(uap->ss, &ss, sizeof(ss)); 635 if (error) 636 return (error); 637 } 638 639 error = kern_sigaltstack(uap->ss ? &ss : NULL, 640 uap->oss ? &oss : NULL); 641 642 if (error == 0 && uap->oss) 643 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 644 return (error); 645 } 646 647 /* 648 * Common code for kill process group/broadcast kill. 649 * cp is calling process. 650 */ 651 struct killpg_info { 652 int nfound; 653 int sig; 654 }; 655 656 static int killpg_all_callback(struct proc *p, void *data); 657 658 static int 659 dokillpg(int sig, int pgid, int all) 660 { 661 struct killpg_info info; 662 struct proc *cp = curproc; 663 struct proc *p; 664 struct pgrp *pgrp; 665 666 info.nfound = 0; 667 info.sig = sig; 668 669 if (all) { 670 /* 671 * broadcast 672 */ 673 allproc_scan(killpg_all_callback, &info); 674 } else { 675 if (pgid == 0) { 676 /* 677 * zero pgid means send to my process group. 678 */ 679 pgrp = cp->p_pgrp; 680 pgref(pgrp); 681 } else { 682 pgrp = pgfind(pgid); 683 if (pgrp == NULL) 684 return (ESRCH); 685 } 686 687 /* 688 * Must interlock all signals against fork 689 */ 690 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 691 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 692 if (p->p_pid <= 1 || 693 p->p_stat == SZOMB || 694 (p->p_flags & P_SYSTEM) || 695 !CANSIGNAL(p, sig)) { 696 continue; 697 } 698 ++info.nfound; 699 if (sig) 700 ksignal(p, sig); 701 } 702 lockmgr(&pgrp->pg_lock, LK_RELEASE); 703 pgrel(pgrp); 704 } 705 return (info.nfound ? 0 : ESRCH); 706 } 707 708 static int 709 killpg_all_callback(struct proc *p, void *data) 710 { 711 struct killpg_info *info = data; 712 713 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 714 p == curproc || !CANSIGNAL(p, info->sig)) { 715 return (0); 716 } 717 ++info->nfound; 718 if (info->sig) 719 ksignal(p, info->sig); 720 return(0); 721 } 722 723 /* 724 * Send a general signal to a process or LWPs within that process. 725 * 726 * Note that new signals cannot be sent if a process is exiting or already 727 * a zombie, but we return success anyway as userland is likely to not handle 728 * the race properly. 729 * 730 * No requirements. 731 */ 732 int 733 kern_kill(int sig, pid_t pid, lwpid_t tid) 734 { 735 int t; 736 737 if ((u_int)sig > _SIG_MAXSIG) 738 return (EINVAL); 739 740 lwkt_gettoken(&proc_token); 741 742 if (pid > 0) { 743 struct proc *p; 744 struct lwp *lp = NULL; 745 746 /* 747 * Send a signal to a single process. If the kill() is 748 * racing an exiting process which has not yet been reaped 749 * act as though the signal was delivered successfully but 750 * don't actually try to deliver the signal. 751 */ 752 if ((p = pfind(pid)) == NULL) { 753 if ((p = zpfind(pid)) == NULL) { 754 lwkt_reltoken(&proc_token); 755 return (ESRCH); 756 } 757 lwkt_reltoken(&proc_token); 758 PRELE(p); 759 return (0); 760 } 761 lwkt_gettoken(&p->p_token); 762 if (!CANSIGNAL(p, sig)) { 763 lwkt_reltoken(&p->p_token); 764 PRELE(p); 765 lwkt_reltoken(&proc_token); 766 return (EPERM); 767 } 768 769 /* 770 * NOP if the process is exiting. Note that lwpsignal() is 771 * called directly with P_WEXIT set to kill individual LWPs 772 * during exit, which is allowed. 773 */ 774 if (p->p_flags & P_WEXIT) { 775 lwkt_reltoken(&p->p_token); 776 PRELE(p); 777 lwkt_reltoken(&proc_token); 778 return (0); 779 } 780 if (tid != -1) { 781 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 782 if (lp == NULL) { 783 lwkt_reltoken(&p->p_token); 784 PRELE(p); 785 lwkt_reltoken(&proc_token); 786 return (ESRCH); 787 } 788 } 789 if (sig) 790 lwpsignal(p, lp, sig); 791 lwkt_reltoken(&p->p_token); 792 PRELE(p); 793 lwkt_reltoken(&proc_token); 794 return (0); 795 } 796 797 /* 798 * If we come here, pid is a special broadcast pid. 799 * This doesn't mix with a tid. 800 */ 801 if (tid != -1) { 802 lwkt_reltoken(&proc_token); 803 return (EINVAL); 804 } 805 switch (pid) { 806 case -1: /* broadcast signal */ 807 t = (dokillpg(sig, 0, 1)); 808 break; 809 case 0: /* signal own process group */ 810 t = (dokillpg(sig, 0, 0)); 811 break; 812 default: /* negative explicit process group */ 813 t = (dokillpg(sig, -pid, 0)); 814 break; 815 } 816 lwkt_reltoken(&proc_token); 817 return t; 818 } 819 820 int 821 sys_kill(struct kill_args *uap) 822 { 823 int error; 824 825 error = kern_kill(uap->signum, uap->pid, -1); 826 return (error); 827 } 828 829 int 830 sys_lwp_kill(struct lwp_kill_args *uap) 831 { 832 int error; 833 pid_t pid = uap->pid; 834 835 /* 836 * A tid is mandatory for lwp_kill(), otherwise 837 * you could simply use kill(). 838 */ 839 if (uap->tid == -1) 840 return (EINVAL); 841 842 /* 843 * To save on a getpid() function call for intra-process 844 * signals, pid == -1 means current process. 845 */ 846 if (pid == -1) 847 pid = curproc->p_pid; 848 849 error = kern_kill(uap->signum, pid, uap->tid); 850 return (error); 851 } 852 853 /* 854 * Send a signal to a process group. 855 */ 856 void 857 gsignal(int pgid, int sig) 858 { 859 struct pgrp *pgrp; 860 861 if (pgid && (pgrp = pgfind(pgid))) 862 pgsignal(pgrp, sig, 0); 863 } 864 865 /* 866 * Send a signal to a process group. If checktty is 1, 867 * limit to members which have a controlling terminal. 868 * 869 * pg_lock interlocks against a fork that might be in progress, to 870 * ensure that the new child process picks up the signal. 871 */ 872 void 873 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 874 { 875 struct proc *p; 876 877 /* 878 * Must interlock all signals against fork 879 */ 880 if (pgrp) { 881 pgref(pgrp); 882 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 883 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 884 if (checkctty == 0 || p->p_flags & P_CONTROLT) 885 ksignal(p, sig); 886 } 887 lockmgr(&pgrp->pg_lock, LK_RELEASE); 888 pgrel(pgrp); 889 } 890 } 891 892 /* 893 * Send a signal caused by a trap to the current lwp. If it will be caught 894 * immediately, deliver it with correct code. Otherwise, post it normally. 895 * 896 * These signals may ONLY be delivered to the specified lwp and may never 897 * be delivered to the process generically. 898 */ 899 void 900 trapsignal(struct lwp *lp, int sig, u_long code) 901 { 902 struct proc *p = lp->lwp_proc; 903 struct sigacts *ps = p->p_sigacts; 904 905 /* 906 * If we are a virtual kernel running an emulated user process 907 * context, switch back to the virtual kernel context before 908 * trying to post the signal. 909 */ 910 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 911 struct trapframe *tf = lp->lwp_md.md_regs; 912 tf->tf_trapno = 0; 913 vkernel_trap(lp, tf); 914 } 915 916 917 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 918 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 919 lp->lwp_ru.ru_nsignals++; 920 #ifdef KTRACE 921 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 922 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 923 &lp->lwp_sigmask, code); 924 #endif 925 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 926 &lp->lwp_sigmask, code); 927 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 928 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 929 SIGADDSET(lp->lwp_sigmask, sig); 930 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 931 /* 932 * See kern_sigaction() for origin of this code. 933 */ 934 SIGDELSET(p->p_sigcatch, sig); 935 if (sig != SIGCONT && 936 sigprop(sig) & SA_IGNORE) 937 SIGADDSET(p->p_sigignore, sig); 938 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 939 } 940 } else { 941 lp->lwp_code = code; /* XXX for core dump/debugger */ 942 lp->lwp_sig = sig; /* XXX to verify code */ 943 lwpsignal(p, lp, sig); 944 } 945 } 946 947 /* 948 * Find a suitable lwp to deliver the signal to. Returns NULL if all 949 * lwps hold the signal blocked. 950 * 951 * Caller must hold p->p_token. 952 * 953 * Returns a lp or NULL. If non-NULL the lp is held and its token is 954 * acquired. 955 */ 956 static struct lwp * 957 find_lwp_for_signal(struct proc *p, int sig) 958 { 959 struct lwp *lp; 960 struct lwp *run, *sleep, *stop; 961 962 /* 963 * If the running/preempted thread belongs to the proc to which 964 * the signal is being delivered and this thread does not block 965 * the signal, then we can avoid a context switch by delivering 966 * the signal to this thread, because it will return to userland 967 * soon anyways. 968 */ 969 lp = lwkt_preempted_proc(); 970 if (lp != NULL && lp->lwp_proc == p) { 971 LWPHOLD(lp); 972 lwkt_gettoken(&lp->lwp_token); 973 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 974 /* return w/ token held */ 975 return (lp); 976 } 977 lwkt_reltoken(&lp->lwp_token); 978 LWPRELE(lp); 979 } 980 981 run = sleep = stop = NULL; 982 FOREACH_LWP_IN_PROC(lp, p) { 983 /* 984 * If the signal is being blocked by the lwp, then this 985 * lwp is not eligible for receiving the signal. 986 */ 987 LWPHOLD(lp); 988 lwkt_gettoken(&lp->lwp_token); 989 990 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 991 lwkt_reltoken(&lp->lwp_token); 992 LWPRELE(lp); 993 continue; 994 } 995 996 switch (lp->lwp_stat) { 997 case LSRUN: 998 if (sleep) { 999 lwkt_token_swap(); 1000 lwkt_reltoken(&sleep->lwp_token); 1001 LWPRELE(sleep); 1002 sleep = NULL; 1003 run = lp; 1004 } else if (stop) { 1005 lwkt_token_swap(); 1006 lwkt_reltoken(&stop->lwp_token); 1007 LWPRELE(stop); 1008 stop = NULL; 1009 run = lp; 1010 } else { 1011 run = lp; 1012 } 1013 break; 1014 case LSSLEEP: 1015 if (lp->lwp_flags & LWP_SINTR) { 1016 if (sleep) { 1017 lwkt_reltoken(&lp->lwp_token); 1018 LWPRELE(lp); 1019 } else if (stop) { 1020 lwkt_token_swap(); 1021 lwkt_reltoken(&stop->lwp_token); 1022 LWPRELE(stop); 1023 stop = NULL; 1024 sleep = lp; 1025 } else { 1026 sleep = lp; 1027 } 1028 } else { 1029 lwkt_reltoken(&lp->lwp_token); 1030 LWPRELE(lp); 1031 } 1032 break; 1033 case LSSTOP: 1034 if (sleep) { 1035 lwkt_reltoken(&lp->lwp_token); 1036 LWPRELE(lp); 1037 } else if (stop) { 1038 lwkt_reltoken(&lp->lwp_token); 1039 LWPRELE(lp); 1040 } else { 1041 stop = lp; 1042 } 1043 break; 1044 } 1045 if (run) 1046 break; 1047 } 1048 1049 if (run != NULL) 1050 return (run); 1051 else if (sleep != NULL) 1052 return (sleep); 1053 else 1054 return (stop); 1055 } 1056 1057 /* 1058 * Send the signal to the process. If the signal has an action, the action 1059 * is usually performed by the target process rather than the caller; we add 1060 * the signal to the set of pending signals for the process. 1061 * 1062 * Exceptions: 1063 * o When a stop signal is sent to a sleeping process that takes the 1064 * default action, the process is stopped without awakening it. 1065 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1066 * regardless of the signal action (eg, blocked or ignored). 1067 * 1068 * Other ignored signals are discarded immediately. 1069 * 1070 * If the caller wishes to call this function from a hard code section the 1071 * caller must already hold p->p_token (see kern_clock.c). 1072 * 1073 * No requirements. 1074 */ 1075 void 1076 ksignal(struct proc *p, int sig) 1077 { 1078 lwpsignal(p, NULL, sig); 1079 } 1080 1081 /* 1082 * The core for ksignal. lp may be NULL, then a suitable thread 1083 * will be chosen. If not, lp MUST be a member of p. 1084 * 1085 * If the caller wishes to call this function from a hard code section the 1086 * caller must already hold p->p_token. 1087 * 1088 * No requirements. 1089 */ 1090 void 1091 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1092 { 1093 struct proc *q; 1094 sig_t action; 1095 int prop; 1096 1097 if (sig > _SIG_MAXSIG || sig <= 0) { 1098 kprintf("lwpsignal: signal %d\n", sig); 1099 panic("lwpsignal signal number"); 1100 } 1101 1102 KKASSERT(lp == NULL || lp->lwp_proc == p); 1103 1104 /* 1105 * We don't want to race... well, all sorts of things. Get appropriate 1106 * tokens. 1107 * 1108 * Don't try to deliver a generic signal to an exiting process, 1109 * the signal structures could be in flux. We check the LWP later 1110 * on. 1111 */ 1112 PHOLD(p); 1113 lwkt_gettoken(&p->p_token); 1114 if (lp) { 1115 LWPHOLD(lp); 1116 lwkt_gettoken(&lp->lwp_token); 1117 } else if (p->p_flags & P_WEXIT) { 1118 goto out; 1119 } 1120 1121 prop = sigprop(sig); 1122 1123 /* 1124 * If proc is traced, always give parent a chance; 1125 * if signal event is tracked by procfs, give *that* 1126 * a chance, as well. 1127 */ 1128 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1129 action = SIG_DFL; 1130 } else { 1131 /* 1132 * Do not try to deliver signals to an exiting lwp. Note 1133 * that we must still deliver the signal if P_WEXIT is set 1134 * in the process flags. 1135 */ 1136 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT)) { 1137 if (lp) { 1138 lwkt_reltoken(&lp->lwp_token); 1139 LWPRELE(lp); 1140 } 1141 lwkt_reltoken(&p->p_token); 1142 PRELE(p); 1143 return; 1144 } 1145 1146 /* 1147 * If the signal is being ignored, then we forget about 1148 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1149 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1150 */ 1151 if (SIGISMEMBER(p->p_sigignore, sig)) { 1152 /* 1153 * Even if a signal is set SIG_IGN, it may still be 1154 * lurking in a kqueue. 1155 */ 1156 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1157 if (lp) { 1158 lwkt_reltoken(&lp->lwp_token); 1159 LWPRELE(lp); 1160 } 1161 lwkt_reltoken(&p->p_token); 1162 PRELE(p); 1163 return; 1164 } 1165 if (SIGISMEMBER(p->p_sigcatch, sig)) 1166 action = SIG_CATCH; 1167 else 1168 action = SIG_DFL; 1169 } 1170 1171 /* 1172 * If continuing, clear any pending STOP signals. 1173 */ 1174 if (prop & SA_CONT) 1175 SIG_STOPSIGMASK(p->p_siglist); 1176 1177 if (prop & SA_STOP) { 1178 /* 1179 * If sending a tty stop signal to a member of an orphaned 1180 * process group, discard the signal here if the action 1181 * is default; don't stop the process below if sleeping, 1182 * and don't clear any pending SIGCONT. 1183 */ 1184 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1185 action == SIG_DFL) { 1186 lwkt_reltoken(&p->p_token); 1187 PRELE(p); 1188 return; 1189 } 1190 SIG_CONTSIGMASK(p->p_siglist); 1191 p->p_flags &= ~P_CONTINUED; 1192 } 1193 1194 if (p->p_stat == SSTOP) { 1195 /* 1196 * Nobody can handle this signal, add it to the lwp or 1197 * process pending list 1198 */ 1199 if (lp) { 1200 spin_lock(&lp->lwp_spin); 1201 SIGADDSET(lp->lwp_siglist, sig); 1202 spin_unlock(&lp->lwp_spin); 1203 } else { 1204 SIGADDSET(p->p_siglist, sig); 1205 } 1206 1207 /* 1208 * If the process is stopped and is being traced, then no 1209 * further action is necessary. 1210 */ 1211 if (p->p_flags & P_TRACED) 1212 goto out; 1213 1214 /* 1215 * If the process is stopped and receives a KILL signal, 1216 * make the process runnable. 1217 */ 1218 if (sig == SIGKILL) { 1219 proc_unstop(p); 1220 goto active_process; 1221 } 1222 1223 /* 1224 * If the process is stopped and receives a CONT signal, 1225 * then try to make the process runnable again. 1226 */ 1227 if (prop & SA_CONT) { 1228 /* 1229 * If SIGCONT is default (or ignored), we continue the 1230 * process but don't leave the signal in p_siglist, as 1231 * it has no further action. If SIGCONT is held, we 1232 * continue the process and leave the signal in 1233 * p_siglist. If the process catches SIGCONT, let it 1234 * handle the signal itself. 1235 * 1236 * XXX what if the signal is being held blocked? 1237 * 1238 * Token required to interlock kern_wait(). 1239 * Reparenting can also cause a race so we have to 1240 * hold (q). 1241 */ 1242 q = p->p_pptr; 1243 PHOLD(q); 1244 lwkt_gettoken(&q->p_token); 1245 p->p_flags |= P_CONTINUED; 1246 wakeup(q); 1247 if (action == SIG_DFL) 1248 SIGDELSET(p->p_siglist, sig); 1249 proc_unstop(p); 1250 lwkt_reltoken(&q->p_token); 1251 PRELE(q); 1252 if (action == SIG_CATCH) 1253 goto active_process; 1254 goto out; 1255 } 1256 1257 /* 1258 * If the process is stopped and receives another STOP 1259 * signal, we do not need to stop it again. If we did 1260 * the shell could get confused. 1261 * 1262 * However, if the current/preempted lwp is part of the 1263 * process receiving the signal, we need to keep it, 1264 * so that this lwp can stop in issignal() later, as 1265 * we don't want to wait until it reaches userret! 1266 */ 1267 if (prop & SA_STOP) { 1268 if (lwkt_preempted_proc() == NULL || 1269 lwkt_preempted_proc()->lwp_proc != p) 1270 SIGDELSET(p->p_siglist, sig); 1271 } 1272 1273 /* 1274 * Otherwise the process is stopped and it received some 1275 * signal, which does not change its stopped state. When 1276 * the process is continued a wakeup(p) will be issued which 1277 * will wakeup any threads sleeping in tstop(). 1278 */ 1279 if (lp == NULL) { 1280 /* NOTE: returns lp w/ token held */ 1281 lp = find_lwp_for_signal(p, sig); 1282 } 1283 goto out; 1284 1285 /* NOTREACHED */ 1286 } 1287 /* else not stopped */ 1288 active_process: 1289 1290 /* 1291 * Never deliver a lwp-specific signal to a random lwp. 1292 */ 1293 if (lp == NULL) { 1294 /* NOTE: returns lp w/ token held */ 1295 lp = find_lwp_for_signal(p, sig); 1296 if (lp) { 1297 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1298 lwkt_reltoken(&lp->lwp_token); 1299 LWPRELE(lp); 1300 lp = NULL; 1301 } 1302 } 1303 } 1304 1305 /* 1306 * Deliver to the process generically if (1) the signal is being 1307 * sent to any thread or (2) we could not find a thread to deliver 1308 * it to. 1309 */ 1310 if (lp == NULL) { 1311 SIGADDSET(p->p_siglist, sig); 1312 goto out; 1313 } 1314 1315 /* 1316 * Deliver to a specific LWP whether it masks it or not. It will 1317 * not be dispatched if masked but we must still deliver it. 1318 */ 1319 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1320 (p->p_flags & P_TRACED) == 0) { 1321 p->p_nice = NZERO; 1322 } 1323 1324 /* 1325 * If the process receives a STOP signal which indeed needs to 1326 * stop the process, do so. If the process chose to catch the 1327 * signal, it will be treated like any other signal. 1328 */ 1329 if ((prop & SA_STOP) && action == SIG_DFL) { 1330 /* 1331 * If a child holding parent blocked, stopping 1332 * could cause deadlock. Take no action at this 1333 * time. 1334 */ 1335 if (p->p_flags & P_PPWAIT) { 1336 SIGADDSET(p->p_siglist, sig); 1337 goto out; 1338 } 1339 1340 /* 1341 * Do not actually try to manipulate the process, but simply 1342 * stop it. Lwps will stop as soon as they safely can. 1343 * 1344 * Ignore stop if the process is exiting. 1345 */ 1346 if ((p->p_flags & P_WEXIT) == 0) { 1347 p->p_xstat = sig; 1348 proc_stop(p); 1349 } 1350 goto out; 1351 } 1352 1353 /* 1354 * If it is a CONT signal with default action, just ignore it. 1355 */ 1356 if ((prop & SA_CONT) && action == SIG_DFL) 1357 goto out; 1358 1359 /* 1360 * Mark signal pending at this specific thread. 1361 */ 1362 spin_lock(&lp->lwp_spin); 1363 SIGADDSET(lp->lwp_siglist, sig); 1364 spin_unlock(&lp->lwp_spin); 1365 1366 lwp_signotify(lp); 1367 1368 out: 1369 if (lp) { 1370 lwkt_reltoken(&lp->lwp_token); 1371 LWPRELE(lp); 1372 } 1373 lwkt_reltoken(&p->p_token); 1374 PRELE(p); 1375 } 1376 1377 /* 1378 * Notify the LWP that a signal has arrived. The LWP does not have to be 1379 * sleeping on the current cpu. 1380 * 1381 * p->p_token and lp->lwp_token must be held on call. 1382 * 1383 * We can only safely schedule the thread on its current cpu and only if 1384 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1385 * the correct cpu we are properly interlocked, otherwise we could be 1386 * racing other thread transition states (or the lwp is on the user scheduler 1387 * runq but not scheduled) and must not do anything. 1388 * 1389 * Since we hold the lwp token we know the lwp cannot be ripped out from 1390 * under us so we can safely hold it to prevent it from being ripped out 1391 * from under us if we are forced to IPI another cpu to make the local 1392 * checks there. 1393 * 1394 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1395 * which we won't in an IPI so any fixups have to be done here, effectively 1396 * replicating part of what setrunnable() does. 1397 */ 1398 static void 1399 lwp_signotify(struct lwp *lp) 1400 { 1401 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1402 1403 crit_enter(); 1404 if (lp == lwkt_preempted_proc()) { 1405 /* 1406 * lwp is on the current cpu AND it is currently running 1407 * (we preempted it). 1408 */ 1409 signotify(); 1410 } else if (lp->lwp_flags & LWP_SINTR) { 1411 /* 1412 * lwp is sitting in tsleep() with PCATCH set 1413 */ 1414 #ifdef SMP 1415 if (lp->lwp_thread->td_gd == mycpu) { 1416 setrunnable(lp); 1417 } else { 1418 /* 1419 * We can only adjust lwp_stat while we hold the 1420 * lwp_token, and we won't in the IPI function. 1421 */ 1422 LWPHOLD(lp); 1423 if (lp->lwp_stat == LSSTOP) 1424 lp->lwp_stat = LSSLEEP; 1425 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1426 lwp_signotify_remote, lp); 1427 } 1428 #else 1429 setrunnable(lp); 1430 #endif 1431 } else if (lp->lwp_thread->td_flags & TDF_SINTR) { 1432 /* 1433 * lwp is sitting in lwkt_sleep() with PCATCH set. 1434 */ 1435 #ifdef SMP 1436 if (lp->lwp_thread->td_gd == mycpu) { 1437 setrunnable(lp); 1438 } else { 1439 /* 1440 * We can only adjust lwp_stat while we hold the 1441 * lwp_token, and we won't in the IPI function. 1442 */ 1443 LWPHOLD(lp); 1444 if (lp->lwp_stat == LSSTOP) 1445 lp->lwp_stat = LSSLEEP; 1446 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1447 lwp_signotify_remote, lp); 1448 } 1449 #else 1450 setrunnable(lp); 1451 #endif 1452 } else { 1453 /* 1454 * Otherwise the lwp is either in some uninterruptable state 1455 * or it is on the userland scheduler's runqueue waiting to 1456 * be scheduled to a cpu. 1457 */ 1458 } 1459 crit_exit(); 1460 } 1461 1462 #ifdef SMP 1463 1464 /* 1465 * This function is called via an IPI so we cannot call setrunnable() here 1466 * (because while we hold the lp we don't own its token, and can't get it 1467 * from an IPI). 1468 * 1469 * We are interlocked by virtue of being on the same cpu as the target. If 1470 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1471 * the target thread. 1472 */ 1473 static void 1474 lwp_signotify_remote(void *arg) 1475 { 1476 struct lwp *lp = arg; 1477 thread_t td = lp->lwp_thread; 1478 1479 if (lp == lwkt_preempted_proc()) { 1480 signotify(); 1481 LWPRELE(lp); 1482 } else if (td->td_gd == mycpu) { 1483 if ((lp->lwp_flags & LWP_SINTR) || 1484 (td->td_flags & TDF_SINTR)) { 1485 lwkt_schedule(td); 1486 } 1487 LWPRELE(lp); 1488 } else { 1489 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1490 /* LWPHOLD() is forwarded to the target cpu */ 1491 } 1492 } 1493 1494 #endif 1495 1496 /* 1497 * Caller must hold p->p_token 1498 */ 1499 void 1500 proc_stop(struct proc *p) 1501 { 1502 struct proc *q; 1503 struct lwp *lp; 1504 1505 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1506 1507 /* If somebody raced us, be happy with it */ 1508 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1509 return; 1510 } 1511 p->p_stat = SSTOP; 1512 1513 FOREACH_LWP_IN_PROC(lp, p) { 1514 LWPHOLD(lp); 1515 lwkt_gettoken(&lp->lwp_token); 1516 1517 switch (lp->lwp_stat) { 1518 case LSSTOP: 1519 /* 1520 * Do nothing, we are already counted in 1521 * p_nstopped. 1522 */ 1523 break; 1524 1525 case LSSLEEP: 1526 /* 1527 * We're sleeping, but we will stop before 1528 * returning to userspace, so count us 1529 * as stopped as well. We set LWP_MP_WSTOP 1530 * to signal the lwp that it should not 1531 * increase p_nstopped when reaching tstop(). 1532 * 1533 * LWP_MP_WSTOP is protected by lp->lwp_token. 1534 */ 1535 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1536 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1537 ++p->p_nstopped; 1538 } 1539 break; 1540 1541 case LSRUN: 1542 /* 1543 * We might notify ourself, but that's not 1544 * a problem. 1545 */ 1546 lwp_signotify(lp); 1547 break; 1548 } 1549 lwkt_reltoken(&lp->lwp_token); 1550 LWPRELE(lp); 1551 } 1552 1553 if (p->p_nstopped == p->p_nthreads) { 1554 /* 1555 * Token required to interlock kern_wait(). Reparenting can 1556 * also cause a race so we have to hold (q). 1557 */ 1558 q = p->p_pptr; 1559 PHOLD(q); 1560 lwkt_gettoken(&q->p_token); 1561 p->p_flags &= ~P_WAITED; 1562 wakeup(q); 1563 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1564 ksignal(p->p_pptr, SIGCHLD); 1565 lwkt_reltoken(&q->p_token); 1566 PRELE(q); 1567 } 1568 } 1569 1570 /* 1571 * Caller must hold proc_token 1572 */ 1573 void 1574 proc_unstop(struct proc *p) 1575 { 1576 struct lwp *lp; 1577 1578 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1579 1580 if (p->p_stat != SSTOP) 1581 return; 1582 1583 p->p_stat = SACTIVE; 1584 1585 FOREACH_LWP_IN_PROC(lp, p) { 1586 LWPHOLD(lp); 1587 lwkt_gettoken(&lp->lwp_token); 1588 1589 switch (lp->lwp_stat) { 1590 case LSRUN: 1591 /* 1592 * Uh? Not stopped? Well, I guess that's okay. 1593 */ 1594 if (bootverbose) 1595 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1596 p->p_pid, lp->lwp_tid); 1597 break; 1598 1599 case LSSLEEP: 1600 /* 1601 * Still sleeping. Don't bother waking it up. 1602 * However, if this thread was counted as 1603 * stopped, undo this. 1604 * 1605 * Nevertheless we call setrunnable() so that it 1606 * will wake up in case a signal or timeout arrived 1607 * in the meantime. 1608 * 1609 * LWP_MP_WSTOP is protected by lp->lwp_token. 1610 */ 1611 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1612 atomic_clear_int(&lp->lwp_mpflags, 1613 LWP_MP_WSTOP); 1614 --p->p_nstopped; 1615 } else { 1616 if (bootverbose) 1617 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1618 p->p_pid, lp->lwp_tid); 1619 } 1620 /* FALLTHROUGH */ 1621 1622 case LSSTOP: 1623 /* 1624 * This handles any lwp's waiting in a tsleep with 1625 * SIGCATCH. 1626 */ 1627 lwp_signotify(lp); 1628 break; 1629 1630 } 1631 lwkt_reltoken(&lp->lwp_token); 1632 LWPRELE(lp); 1633 } 1634 1635 /* 1636 * This handles any lwp's waiting in tstop(). We have interlocked 1637 * the setting of p_stat by acquiring and releasing each lpw's 1638 * token. 1639 */ 1640 wakeup(p); 1641 } 1642 1643 /* 1644 * No requirements. 1645 */ 1646 static int 1647 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1648 { 1649 sigset_t savedmask, set; 1650 struct proc *p = curproc; 1651 struct lwp *lp = curthread->td_lwp; 1652 int error, sig, hz, timevalid = 0; 1653 struct timespec rts, ets, ts; 1654 struct timeval tv; 1655 1656 error = 0; 1657 sig = 0; 1658 ets.tv_sec = 0; /* silence compiler warning */ 1659 ets.tv_nsec = 0; /* silence compiler warning */ 1660 SIG_CANTMASK(waitset); 1661 savedmask = lp->lwp_sigmask; 1662 1663 if (timeout) { 1664 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1665 timeout->tv_nsec < 1000000000) { 1666 timevalid = 1; 1667 getnanouptime(&rts); 1668 ets = rts; 1669 timespecadd(&ets, timeout); 1670 } 1671 } 1672 1673 for (;;) { 1674 set = lwp_sigpend(lp); 1675 SIGSETAND(set, waitset); 1676 if ((sig = sig_ffs(&set)) != 0) { 1677 SIGFILLSET(lp->lwp_sigmask); 1678 SIGDELSET(lp->lwp_sigmask, sig); 1679 SIG_CANTMASK(lp->lwp_sigmask); 1680 sig = issignal(lp, 1); 1681 /* 1682 * It may be a STOP signal, in the case, issignal 1683 * returns 0, because we may stop there, and new 1684 * signal can come in, we should restart if we got 1685 * nothing. 1686 */ 1687 if (sig == 0) 1688 continue; 1689 else 1690 break; 1691 } 1692 1693 /* 1694 * Previous checking got nothing, and we retried but still 1695 * got nothing, we should return the error status. 1696 */ 1697 if (error) 1698 break; 1699 1700 /* 1701 * POSIX says this must be checked after looking for pending 1702 * signals. 1703 */ 1704 if (timeout) { 1705 if (timevalid == 0) { 1706 error = EINVAL; 1707 break; 1708 } 1709 getnanouptime(&rts); 1710 if (timespeccmp(&rts, &ets, >=)) { 1711 error = EAGAIN; 1712 break; 1713 } 1714 ts = ets; 1715 timespecsub(&ts, &rts); 1716 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1717 hz = tvtohz_high(&tv); 1718 } else { 1719 hz = 0; 1720 } 1721 1722 lp->lwp_sigmask = savedmask; 1723 SIGSETNAND(lp->lwp_sigmask, waitset); 1724 /* 1725 * We won't ever be woken up. Instead, our sleep will 1726 * be broken in lwpsignal(). 1727 */ 1728 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1729 if (timeout) { 1730 if (error == ERESTART) { 1731 /* can not restart a timeout wait. */ 1732 error = EINTR; 1733 } else if (error == EAGAIN) { 1734 /* will calculate timeout by ourself. */ 1735 error = 0; 1736 } 1737 } 1738 /* Retry ... */ 1739 } 1740 1741 lp->lwp_sigmask = savedmask; 1742 if (sig) { 1743 error = 0; 1744 bzero(info, sizeof(*info)); 1745 info->si_signo = sig; 1746 spin_lock(&lp->lwp_spin); 1747 lwp_delsig(lp, sig); /* take the signal! */ 1748 spin_unlock(&lp->lwp_spin); 1749 1750 if (sig == SIGKILL) { 1751 sigexit(lp, sig); 1752 /* NOT REACHED */ 1753 } 1754 } 1755 1756 return (error); 1757 } 1758 1759 /* 1760 * MPALMOSTSAFE 1761 */ 1762 int 1763 sys_sigtimedwait(struct sigtimedwait_args *uap) 1764 { 1765 struct timespec ts; 1766 struct timespec *timeout; 1767 sigset_t set; 1768 siginfo_t info; 1769 int error; 1770 1771 if (uap->timeout) { 1772 error = copyin(uap->timeout, &ts, sizeof(ts)); 1773 if (error) 1774 return (error); 1775 timeout = &ts; 1776 } else { 1777 timeout = NULL; 1778 } 1779 error = copyin(uap->set, &set, sizeof(set)); 1780 if (error) 1781 return (error); 1782 error = kern_sigtimedwait(set, &info, timeout); 1783 if (error) 1784 return (error); 1785 if (uap->info) 1786 error = copyout(&info, uap->info, sizeof(info)); 1787 /* Repost if we got an error. */ 1788 /* 1789 * XXX lwp 1790 * 1791 * This could transform a thread-specific signal to another 1792 * thread / process pending signal. 1793 */ 1794 if (error) { 1795 ksignal(curproc, info.si_signo); 1796 } else { 1797 uap->sysmsg_result = info.si_signo; 1798 } 1799 return (error); 1800 } 1801 1802 /* 1803 * MPALMOSTSAFE 1804 */ 1805 int 1806 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1807 { 1808 siginfo_t info; 1809 sigset_t set; 1810 int error; 1811 1812 error = copyin(uap->set, &set, sizeof(set)); 1813 if (error) 1814 return (error); 1815 error = kern_sigtimedwait(set, &info, NULL); 1816 if (error) 1817 return (error); 1818 if (uap->info) 1819 error = copyout(&info, uap->info, sizeof(info)); 1820 /* Repost if we got an error. */ 1821 /* 1822 * XXX lwp 1823 * 1824 * This could transform a thread-specific signal to another 1825 * thread / process pending signal. 1826 */ 1827 if (error) { 1828 ksignal(curproc, info.si_signo); 1829 } else { 1830 uap->sysmsg_result = info.si_signo; 1831 } 1832 return (error); 1833 } 1834 1835 /* 1836 * If the current process has received a signal that would interrupt a 1837 * system call, return EINTR or ERESTART as appropriate. 1838 */ 1839 int 1840 iscaught(struct lwp *lp) 1841 { 1842 struct proc *p = lp->lwp_proc; 1843 int sig; 1844 1845 if (p) { 1846 if ((sig = CURSIG(lp)) != 0) { 1847 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1848 return (EINTR); 1849 return (ERESTART); 1850 } 1851 } 1852 return(EWOULDBLOCK); 1853 } 1854 1855 /* 1856 * If the current process has received a signal (should be caught or cause 1857 * termination, should interrupt current syscall), return the signal number. 1858 * Stop signals with default action are processed immediately, then cleared; 1859 * they aren't returned. This is checked after each entry to the system for 1860 * a syscall or trap (though this can usually be done without calling issignal 1861 * by checking the pending signal masks in the CURSIG macro). 1862 * 1863 * This routine is called via CURSIG/__cursig. We will acquire and release 1864 * p->p_token but if the caller needs to interlock the test the caller must 1865 * also hold p->p_token. 1866 * 1867 * while (sig = CURSIG(curproc)) 1868 * postsig(sig); 1869 * 1870 * MPSAFE 1871 */ 1872 int 1873 issignal(struct lwp *lp, int maytrace) 1874 { 1875 struct proc *p = lp->lwp_proc; 1876 sigset_t mask; 1877 int sig, prop; 1878 1879 lwkt_gettoken(&p->p_token); 1880 1881 for (;;) { 1882 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1883 1884 /* 1885 * If this process is supposed to stop, stop this thread. 1886 */ 1887 if (p->p_stat == SSTOP) 1888 tstop(); 1889 1890 mask = lwp_sigpend(lp); 1891 SIGSETNAND(mask, lp->lwp_sigmask); 1892 if (p->p_flags & P_PPWAIT) 1893 SIG_STOPSIGMASK(mask); 1894 if (SIGISEMPTY(mask)) { /* no signal to send */ 1895 lwkt_reltoken(&p->p_token); 1896 return (0); 1897 } 1898 sig = sig_ffs(&mask); 1899 1900 STOPEVENT(p, S_SIG, sig); 1901 1902 /* 1903 * We should see pending but ignored signals 1904 * only if P_TRACED was on when they were posted. 1905 */ 1906 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1907 spin_lock(&lp->lwp_spin); 1908 lwp_delsig(lp, sig); 1909 spin_unlock(&lp->lwp_spin); 1910 continue; 1911 } 1912 if (maytrace && 1913 (p->p_flags & P_TRACED) && 1914 (p->p_flags & P_PPWAIT) == 0) { 1915 /* 1916 * If traced, always stop, and stay stopped until 1917 * released by the parent. 1918 * 1919 * NOTE: SSTOP may get cleared during the loop, 1920 * but we do not re-notify the parent if we have 1921 * to loop several times waiting for the parent 1922 * to let us continue. 1923 * 1924 * XXX not sure if this is still true 1925 */ 1926 p->p_xstat = sig; 1927 proc_stop(p); 1928 do { 1929 tstop(); 1930 } while (!trace_req(p) && (p->p_flags & P_TRACED)); 1931 1932 /* 1933 * If parent wants us to take the signal, 1934 * then it will leave it in p->p_xstat; 1935 * otherwise we just look for signals again. 1936 */ 1937 spin_lock(&lp->lwp_spin); 1938 lwp_delsig(lp, sig); /* clear old signal */ 1939 spin_unlock(&lp->lwp_spin); 1940 sig = p->p_xstat; 1941 if (sig == 0) 1942 continue; 1943 1944 /* 1945 * Put the new signal into p_siglist. If the 1946 * signal is being masked, look for other signals. 1947 * 1948 * XXX lwp might need a call to ksignal() 1949 */ 1950 SIGADDSET(p->p_siglist, sig); 1951 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1952 continue; 1953 1954 /* 1955 * If the traced bit got turned off, go back up 1956 * to the top to rescan signals. This ensures 1957 * that p_sig* and ps_sigact are consistent. 1958 */ 1959 if ((p->p_flags & P_TRACED) == 0) 1960 continue; 1961 } 1962 1963 prop = sigprop(sig); 1964 1965 /* 1966 * Decide whether the signal should be returned. 1967 * Return the signal's number, or fall through 1968 * to clear it from the pending mask. 1969 */ 1970 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1971 case (intptr_t)SIG_DFL: 1972 /* 1973 * Don't take default actions on system processes. 1974 */ 1975 if (p->p_pid <= 1) { 1976 #ifdef DIAGNOSTIC 1977 /* 1978 * Are you sure you want to ignore SIGSEGV 1979 * in init? XXX 1980 */ 1981 kprintf("Process (pid %lu) got signal %d\n", 1982 (u_long)p->p_pid, sig); 1983 #endif 1984 break; /* == ignore */ 1985 } 1986 1987 /* 1988 * Handle the in-kernel checkpoint action 1989 */ 1990 if (prop & SA_CKPT) { 1991 checkpoint_signal_handler(lp); 1992 break; 1993 } 1994 1995 /* 1996 * If there is a pending stop signal to process 1997 * with default action, stop here, 1998 * then clear the signal. However, 1999 * if process is member of an orphaned 2000 * process group, ignore tty stop signals. 2001 */ 2002 if (prop & SA_STOP) { 2003 if (p->p_flags & P_TRACED || 2004 (p->p_pgrp->pg_jobc == 0 && 2005 prop & SA_TTYSTOP)) 2006 break; /* == ignore */ 2007 if ((p->p_flags & P_WEXIT) == 0) { 2008 p->p_xstat = sig; 2009 proc_stop(p); 2010 tstop(); 2011 } 2012 break; 2013 } else if (prop & SA_IGNORE) { 2014 /* 2015 * Except for SIGCONT, shouldn't get here. 2016 * Default action is to ignore; drop it. 2017 */ 2018 break; /* == ignore */ 2019 } else { 2020 lwkt_reltoken(&p->p_token); 2021 return (sig); 2022 } 2023 2024 /*NOTREACHED*/ 2025 2026 case (intptr_t)SIG_IGN: 2027 /* 2028 * Masking above should prevent us ever trying 2029 * to take action on an ignored signal other 2030 * than SIGCONT, unless process is traced. 2031 */ 2032 if ((prop & SA_CONT) == 0 && 2033 (p->p_flags & P_TRACED) == 0) 2034 kprintf("issignal\n"); 2035 break; /* == ignore */ 2036 2037 default: 2038 /* 2039 * This signal has an action, let 2040 * postsig() process it. 2041 */ 2042 lwkt_reltoken(&p->p_token); 2043 return (sig); 2044 } 2045 spin_lock(&lp->lwp_spin); 2046 lwp_delsig(lp, sig); /* take the signal! */ 2047 spin_unlock(&lp->lwp_spin); 2048 } 2049 /* NOTREACHED */ 2050 } 2051 2052 /* 2053 * Take the action for the specified signal 2054 * from the current set of pending signals. 2055 * 2056 * Caller must hold p->p_token 2057 */ 2058 void 2059 postsig(int sig) 2060 { 2061 struct lwp *lp = curthread->td_lwp; 2062 struct proc *p = lp->lwp_proc; 2063 struct sigacts *ps = p->p_sigacts; 2064 sig_t action; 2065 sigset_t returnmask; 2066 int code; 2067 2068 KASSERT(sig != 0, ("postsig")); 2069 2070 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2071 2072 /* 2073 * If we are a virtual kernel running an emulated user process 2074 * context, switch back to the virtual kernel context before 2075 * trying to post the signal. 2076 */ 2077 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2078 struct trapframe *tf = lp->lwp_md.md_regs; 2079 tf->tf_trapno = 0; 2080 vkernel_trap(lp, tf); 2081 } 2082 2083 spin_lock(&lp->lwp_spin); 2084 lwp_delsig(lp, sig); 2085 spin_unlock(&lp->lwp_spin); 2086 action = ps->ps_sigact[_SIG_IDX(sig)]; 2087 #ifdef KTRACE 2088 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2089 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2090 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2091 #endif 2092 STOPEVENT(p, S_SIG, sig); 2093 2094 if (action == SIG_DFL) { 2095 /* 2096 * Default action, where the default is to kill 2097 * the process. (Other cases were ignored above.) 2098 */ 2099 sigexit(lp, sig); 2100 /* NOTREACHED */ 2101 } else { 2102 /* 2103 * If we get here, the signal must be caught. 2104 */ 2105 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2106 ("postsig action")); 2107 2108 /* 2109 * Reset the signal handler if asked to 2110 */ 2111 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2112 /* 2113 * See kern_sigaction() for origin of this code. 2114 */ 2115 SIGDELSET(p->p_sigcatch, sig); 2116 if (sig != SIGCONT && 2117 sigprop(sig) & SA_IGNORE) 2118 SIGADDSET(p->p_sigignore, sig); 2119 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2120 } 2121 2122 /* 2123 * Set the signal mask and calculate the mask to restore 2124 * when the signal function returns. 2125 * 2126 * Special case: user has done a sigsuspend. Here the 2127 * current mask is not of interest, but rather the 2128 * mask from before the sigsuspend is what we want 2129 * restored after the signal processing is completed. 2130 */ 2131 if (lp->lwp_flags & LWP_OLDMASK) { 2132 returnmask = lp->lwp_oldsigmask; 2133 lp->lwp_flags &= ~LWP_OLDMASK; 2134 } else { 2135 returnmask = lp->lwp_sigmask; 2136 } 2137 2138 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2139 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2140 SIGADDSET(lp->lwp_sigmask, sig); 2141 2142 lp->lwp_ru.ru_nsignals++; 2143 if (lp->lwp_sig != sig) { 2144 code = 0; 2145 } else { 2146 code = lp->lwp_code; 2147 lp->lwp_code = 0; 2148 lp->lwp_sig = 0; 2149 } 2150 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2151 } 2152 } 2153 2154 /* 2155 * Kill the current process for stated reason. 2156 */ 2157 void 2158 killproc(struct proc *p, char *why) 2159 { 2160 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2161 p->p_pid, p->p_comm, 2162 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2163 ksignal(p, SIGKILL); 2164 } 2165 2166 /* 2167 * Force the current process to exit with the specified signal, dumping core 2168 * if appropriate. We bypass the normal tests for masked and caught signals, 2169 * allowing unrecoverable failures to terminate the process without changing 2170 * signal state. Mark the accounting record with the signal termination. 2171 * If dumping core, save the signal number for the debugger. Calls exit and 2172 * does not return. 2173 * 2174 * This routine does not return. 2175 */ 2176 void 2177 sigexit(struct lwp *lp, int sig) 2178 { 2179 struct proc *p = lp->lwp_proc; 2180 2181 lwkt_gettoken(&p->p_token); 2182 p->p_acflag |= AXSIG; 2183 if (sigprop(sig) & SA_CORE) { 2184 lp->lwp_sig = sig; 2185 /* 2186 * Log signals which would cause core dumps 2187 * (Log as LOG_INFO to appease those who don't want 2188 * these messages.) 2189 * XXX : Todo, as well as euid, write out ruid too 2190 */ 2191 if (coredump(lp, sig) == 0) 2192 sig |= WCOREFLAG; 2193 if (kern_logsigexit) 2194 log(LOG_INFO, 2195 "pid %d (%s), uid %d: exited on signal %d%s\n", 2196 p->p_pid, p->p_comm, 2197 p->p_ucred ? p->p_ucred->cr_uid : -1, 2198 sig &~ WCOREFLAG, 2199 sig & WCOREFLAG ? " (core dumped)" : ""); 2200 } 2201 lwkt_reltoken(&p->p_token); 2202 exit1(W_EXITCODE(0, sig)); 2203 /* NOTREACHED */ 2204 } 2205 2206 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2207 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2208 sizeof(corefilename), "process corefile name format string"); 2209 2210 /* 2211 * expand_name(name, uid, pid) 2212 * Expand the name described in corefilename, using name, uid, and pid. 2213 * corefilename is a kprintf-like string, with three format specifiers: 2214 * %N name of process ("name") 2215 * %P process id (pid) 2216 * %U user id (uid) 2217 * For example, "%N.core" is the default; they can be disabled completely 2218 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2219 * This is controlled by the sysctl variable kern.corefile (see above). 2220 */ 2221 2222 static char * 2223 expand_name(const char *name, uid_t uid, pid_t pid) 2224 { 2225 char *temp; 2226 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2227 int i, n; 2228 char *format = corefilename; 2229 size_t namelen; 2230 2231 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2232 if (temp == NULL) 2233 return NULL; 2234 namelen = strlen(name); 2235 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2236 int l; 2237 switch (format[i]) { 2238 case '%': /* Format character */ 2239 i++; 2240 switch (format[i]) { 2241 case '%': 2242 temp[n++] = '%'; 2243 break; 2244 case 'N': /* process name */ 2245 if ((n + namelen) > MAXPATHLEN) { 2246 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2247 pid, name, uid, temp, name); 2248 kfree(temp, M_TEMP); 2249 return NULL; 2250 } 2251 memcpy(temp+n, name, namelen); 2252 n += namelen; 2253 break; 2254 case 'P': /* process id */ 2255 l = ksprintf(buf, "%u", pid); 2256 if ((n + l) > MAXPATHLEN) { 2257 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2258 pid, name, uid, temp, name); 2259 kfree(temp, M_TEMP); 2260 return NULL; 2261 } 2262 memcpy(temp+n, buf, l); 2263 n += l; 2264 break; 2265 case 'U': /* user id */ 2266 l = ksprintf(buf, "%u", uid); 2267 if ((n + l) > MAXPATHLEN) { 2268 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2269 pid, name, uid, temp, name); 2270 kfree(temp, M_TEMP); 2271 return NULL; 2272 } 2273 memcpy(temp+n, buf, l); 2274 n += l; 2275 break; 2276 default: 2277 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2278 } 2279 break; 2280 default: 2281 temp[n++] = format[i]; 2282 } 2283 } 2284 temp[n] = '\0'; 2285 return temp; 2286 } 2287 2288 /* 2289 * Dump a process' core. The main routine does some 2290 * policy checking, and creates the name of the coredump; 2291 * then it passes on a vnode and a size limit to the process-specific 2292 * coredump routine if there is one; if there _is not_ one, it returns 2293 * ENOSYS; otherwise it returns the error from the process-specific routine. 2294 * 2295 * The parameter `lp' is the lwp which triggered the coredump. 2296 */ 2297 2298 static int 2299 coredump(struct lwp *lp, int sig) 2300 { 2301 struct proc *p = lp->lwp_proc; 2302 struct vnode *vp; 2303 struct ucred *cred = p->p_ucred; 2304 struct flock lf; 2305 struct nlookupdata nd; 2306 struct vattr vattr; 2307 int error, error1; 2308 char *name; /* name of corefile */ 2309 off_t limit; 2310 2311 STOPEVENT(p, S_CORE, 0); 2312 2313 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2314 return (EFAULT); 2315 2316 /* 2317 * Note that the bulk of limit checking is done after 2318 * the corefile is created. The exception is if the limit 2319 * for corefiles is 0, in which case we don't bother 2320 * creating the corefile at all. This layout means that 2321 * a corefile is truncated instead of not being created, 2322 * if it is larger than the limit. 2323 */ 2324 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2325 if (limit == 0) 2326 return EFBIG; 2327 2328 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2329 if (name == NULL) 2330 return (EINVAL); 2331 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2332 if (error == 0) 2333 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2334 kfree(name, M_TEMP); 2335 if (error) { 2336 nlookup_done(&nd); 2337 return (error); 2338 } 2339 vp = nd.nl_open_vp; 2340 nd.nl_open_vp = NULL; 2341 nlookup_done(&nd); 2342 2343 vn_unlock(vp); 2344 lf.l_whence = SEEK_SET; 2345 lf.l_start = 0; 2346 lf.l_len = 0; 2347 lf.l_type = F_WRLCK; 2348 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2349 if (error) 2350 goto out2; 2351 2352 /* Don't dump to non-regular files or files with links. */ 2353 if (vp->v_type != VREG || 2354 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2355 error = EFAULT; 2356 goto out1; 2357 } 2358 2359 /* Don't dump to files current user does not own */ 2360 if (vattr.va_uid != p->p_ucred->cr_uid) { 2361 error = EFAULT; 2362 goto out1; 2363 } 2364 2365 VATTR_NULL(&vattr); 2366 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2367 vattr.va_size = 0; 2368 VOP_SETATTR(vp, &vattr, cred); 2369 p->p_acflag |= ACORE; 2370 vn_unlock(vp); 2371 2372 error = p->p_sysent->sv_coredump ? 2373 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2374 2375 out1: 2376 lf.l_type = F_UNLCK; 2377 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2378 out2: 2379 error1 = vn_close(vp, FWRITE); 2380 if (error == 0) 2381 error = error1; 2382 return (error); 2383 } 2384 2385 /* 2386 * Nonexistent system call-- signal process (may want to handle it). 2387 * Flag error in case process won't see signal immediately (blocked or ignored). 2388 * 2389 * MPALMOSTSAFE 2390 */ 2391 /* ARGSUSED */ 2392 int 2393 sys_nosys(struct nosys_args *args) 2394 { 2395 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2396 return (EINVAL); 2397 } 2398 2399 /* 2400 * Send a SIGIO or SIGURG signal to a process or process group using 2401 * stored credentials rather than those of the current process. 2402 */ 2403 void 2404 pgsigio(struct sigio *sigio, int sig, int checkctty) 2405 { 2406 if (sigio == NULL) 2407 return; 2408 2409 if (sigio->sio_pgid > 0) { 2410 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2411 sigio->sio_proc)) 2412 ksignal(sigio->sio_proc, sig); 2413 } else if (sigio->sio_pgid < 0) { 2414 struct proc *p; 2415 struct pgrp *pg = sigio->sio_pgrp; 2416 2417 /* 2418 * Must interlock all signals against fork 2419 */ 2420 pgref(pg); 2421 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2422 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2423 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2424 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2425 ksignal(p, sig); 2426 } 2427 lockmgr(&pg->pg_lock, LK_RELEASE); 2428 pgrel(pg); 2429 } 2430 } 2431 2432 static int 2433 filt_sigattach(struct knote *kn) 2434 { 2435 struct proc *p = curproc; 2436 2437 kn->kn_ptr.p_proc = p; 2438 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2439 2440 /* XXX lock the proc here while adding to the list? */ 2441 knote_insert(&p->p_klist, kn); 2442 2443 return (0); 2444 } 2445 2446 static void 2447 filt_sigdetach(struct knote *kn) 2448 { 2449 struct proc *p = kn->kn_ptr.p_proc; 2450 2451 knote_remove(&p->p_klist, kn); 2452 } 2453 2454 /* 2455 * signal knotes are shared with proc knotes, so we apply a mask to 2456 * the hint in order to differentiate them from process hints. This 2457 * could be avoided by using a signal-specific knote list, but probably 2458 * isn't worth the trouble. 2459 */ 2460 static int 2461 filt_signal(struct knote *kn, long hint) 2462 { 2463 if (hint & NOTE_SIGNAL) { 2464 hint &= ~NOTE_SIGNAL; 2465 2466 if (kn->kn_id == hint) 2467 kn->kn_data++; 2468 } 2469 return (kn->kn_data != 0); 2470 } 2471