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