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