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 73 #include <machine/cpu.h> 74 #include <machine/smp.h> 75 76 static int coredump(struct lwp *, int); 77 static char *expand_name(const char *, uid_t, pid_t); 78 static int dokillpg(int sig, int pgid, int all); 79 static int sig_ffs(sigset_t *set); 80 static int sigprop(int sig); 81 static void lwp_signotify(struct lwp *lp); 82 #ifdef SMP 83 static void signotify_remote(void *arg); 84 #endif 85 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 86 struct timespec *timeout); 87 88 static int filt_sigattach(struct knote *kn); 89 static void filt_sigdetach(struct knote *kn); 90 static int filt_signal(struct knote *kn, long hint); 91 92 struct filterops sig_filtops = 93 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 94 95 static int kern_logsigexit = 1; 96 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 97 &kern_logsigexit, 0, 98 "Log processes quitting on abnormal signals to syslog(3)"); 99 100 /* 101 * Can process p, with pcred pc, send the signal sig to process q? 102 */ 103 #define CANSIGNAL(q, sig) \ 104 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 105 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 106 107 /* 108 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 109 */ 110 #define CANSIGIO(ruid, uc, q) \ 111 ((uc)->cr_uid == 0 || \ 112 (ruid) == (q)->p_ucred->cr_ruid || \ 113 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 114 (ruid) == (q)->p_ucred->cr_uid || \ 115 (uc)->cr_uid == (q)->p_ucred->cr_uid) 116 117 int sugid_coredump; 118 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 119 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 120 121 static int do_coredump = 1; 122 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 123 &do_coredump, 0, "Enable/Disable coredumps"); 124 125 /* 126 * Signal properties and actions. 127 * The array below categorizes the signals and their default actions 128 * according to the following properties: 129 */ 130 #define SA_KILL 0x01 /* terminates process by default */ 131 #define SA_CORE 0x02 /* ditto and coredumps */ 132 #define SA_STOP 0x04 /* suspend process */ 133 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 134 #define SA_IGNORE 0x10 /* ignore by default */ 135 #define SA_CONT 0x20 /* continue if suspended */ 136 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 137 #define SA_CKPT 0x80 /* checkpoint process */ 138 139 140 static int sigproptbl[NSIG] = { 141 SA_KILL, /* SIGHUP */ 142 SA_KILL, /* SIGINT */ 143 SA_KILL|SA_CORE, /* SIGQUIT */ 144 SA_KILL|SA_CORE, /* SIGILL */ 145 SA_KILL|SA_CORE, /* SIGTRAP */ 146 SA_KILL|SA_CORE, /* SIGABRT */ 147 SA_KILL|SA_CORE, /* SIGEMT */ 148 SA_KILL|SA_CORE, /* SIGFPE */ 149 SA_KILL, /* SIGKILL */ 150 SA_KILL|SA_CORE, /* SIGBUS */ 151 SA_KILL|SA_CORE, /* SIGSEGV */ 152 SA_KILL|SA_CORE, /* SIGSYS */ 153 SA_KILL, /* SIGPIPE */ 154 SA_KILL, /* SIGALRM */ 155 SA_KILL, /* SIGTERM */ 156 SA_IGNORE, /* SIGURG */ 157 SA_STOP, /* SIGSTOP */ 158 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 159 SA_IGNORE|SA_CONT, /* SIGCONT */ 160 SA_IGNORE, /* SIGCHLD */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 163 SA_IGNORE, /* SIGIO */ 164 SA_KILL, /* SIGXCPU */ 165 SA_KILL, /* SIGXFSZ */ 166 SA_KILL, /* SIGVTALRM */ 167 SA_KILL, /* SIGPROF */ 168 SA_IGNORE, /* SIGWINCH */ 169 SA_IGNORE, /* SIGINFO */ 170 SA_KILL, /* SIGUSR1 */ 171 SA_KILL, /* SIGUSR2 */ 172 SA_IGNORE, /* SIGTHR */ 173 SA_CKPT, /* SIGCKPT */ 174 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 206 }; 207 208 static __inline int 209 sigprop(int sig) 210 { 211 212 if (sig > 0 && sig < NSIG) 213 return (sigproptbl[_SIG_IDX(sig)]); 214 return (0); 215 } 216 217 static __inline int 218 sig_ffs(sigset_t *set) 219 { 220 int i; 221 222 for (i = 0; i < _SIG_WORDS; i++) 223 if (set->__bits[i]) 224 return (ffs(set->__bits[i]) + (i * 32)); 225 return (0); 226 } 227 228 /* 229 * No requirements. 230 */ 231 int 232 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 233 { 234 struct thread *td = curthread; 235 struct proc *p = td->td_proc; 236 struct lwp *lp; 237 struct sigacts *ps = p->p_sigacts; 238 239 if (sig <= 0 || sig > _SIG_MAXSIG) 240 return (EINVAL); 241 242 lwkt_gettoken(&p->p_token); 243 244 if (oact) { 245 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 246 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 247 oact->sa_flags = 0; 248 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 249 oact->sa_flags |= SA_ONSTACK; 250 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 251 oact->sa_flags |= SA_RESTART; 252 if (SIGISMEMBER(ps->ps_sigreset, sig)) 253 oact->sa_flags |= SA_RESETHAND; 254 if (SIGISMEMBER(ps->ps_signodefer, sig)) 255 oact->sa_flags |= SA_NODEFER; 256 if (SIGISMEMBER(ps->ps_siginfo, sig)) 257 oact->sa_flags |= SA_SIGINFO; 258 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 259 oact->sa_flags |= SA_MAILBOX; 260 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 261 oact->sa_flags |= SA_NOCLDSTOP; 262 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 263 oact->sa_flags |= SA_NOCLDWAIT; 264 } 265 if (act) { 266 /* 267 * Check for invalid requests. KILL and STOP cannot be 268 * caught. 269 */ 270 if (sig == SIGKILL || sig == SIGSTOP) { 271 if (act->sa_handler != SIG_DFL) { 272 lwkt_reltoken(&p->p_token); 273 return (EINVAL); 274 } 275 #if 0 276 /* (not needed, SIG_DFL forces action to occur) */ 277 if (act->sa_flags & SA_MAILBOX) { 278 lwkt_reltoken(&p->p_token); 279 return (EINVAL); 280 } 281 #endif 282 } 283 284 /* 285 * Change setting atomically. 286 */ 287 crit_enter(); 288 289 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 290 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 291 if (act->sa_flags & SA_SIGINFO) { 292 ps->ps_sigact[_SIG_IDX(sig)] = 293 (__sighandler_t *)act->sa_sigaction; 294 SIGADDSET(ps->ps_siginfo, sig); 295 } else { 296 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 297 SIGDELSET(ps->ps_siginfo, sig); 298 } 299 if (!(act->sa_flags & SA_RESTART)) 300 SIGADDSET(ps->ps_sigintr, sig); 301 else 302 SIGDELSET(ps->ps_sigintr, sig); 303 if (act->sa_flags & SA_ONSTACK) 304 SIGADDSET(ps->ps_sigonstack, sig); 305 else 306 SIGDELSET(ps->ps_sigonstack, sig); 307 if (act->sa_flags & SA_RESETHAND) 308 SIGADDSET(ps->ps_sigreset, sig); 309 else 310 SIGDELSET(ps->ps_sigreset, sig); 311 if (act->sa_flags & SA_NODEFER) 312 SIGADDSET(ps->ps_signodefer, sig); 313 else 314 SIGDELSET(ps->ps_signodefer, sig); 315 if (act->sa_flags & SA_MAILBOX) 316 SIGADDSET(ps->ps_sigmailbox, sig); 317 else 318 SIGDELSET(ps->ps_sigmailbox, sig); 319 if (sig == SIGCHLD) { 320 if (act->sa_flags & SA_NOCLDSTOP) 321 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 322 else 323 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 324 if (act->sa_flags & SA_NOCLDWAIT) { 325 /* 326 * Paranoia: since SA_NOCLDWAIT is implemented 327 * by reparenting the dying child to PID 1 (and 328 * trust it to reap the zombie), PID 1 itself 329 * is forbidden to set SA_NOCLDWAIT. 330 */ 331 if (p->p_pid == 1) 332 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 333 else 334 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 335 } else { 336 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 337 } 338 } 339 /* 340 * Set bit in p_sigignore for signals that are set to SIG_IGN, 341 * and for signals set to SIG_DFL where the default is to 342 * ignore. However, don't put SIGCONT in p_sigignore, as we 343 * have to restart the process. 344 */ 345 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 346 (sigprop(sig) & SA_IGNORE && 347 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 348 /* never to be seen again */ 349 SIGDELSET(p->p_siglist, sig); 350 /* 351 * Remove the signal also from the thread lists. 352 */ 353 FOREACH_LWP_IN_PROC(lp, p) { 354 LWPHOLD(lp); 355 lwkt_gettoken(&lp->lwp_token); 356 SIGDELSET(lp->lwp_siglist, sig); 357 lwkt_reltoken(&lp->lwp_token); 358 LWPRELE(lp); 359 } 360 if (sig != SIGCONT) { 361 /* easier in ksignal */ 362 SIGADDSET(p->p_sigignore, sig); 363 } 364 SIGDELSET(p->p_sigcatch, sig); 365 } else { 366 SIGDELSET(p->p_sigignore, sig); 367 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 368 SIGDELSET(p->p_sigcatch, sig); 369 else 370 SIGADDSET(p->p_sigcatch, sig); 371 } 372 373 crit_exit(); 374 } 375 lwkt_reltoken(&p->p_token); 376 return (0); 377 } 378 379 int 380 sys_sigaction(struct sigaction_args *uap) 381 { 382 struct sigaction act, oact; 383 struct sigaction *actp, *oactp; 384 int error; 385 386 actp = (uap->act != NULL) ? &act : NULL; 387 oactp = (uap->oact != NULL) ? &oact : NULL; 388 if (actp) { 389 error = copyin(uap->act, actp, sizeof(act)); 390 if (error) 391 return (error); 392 } 393 error = kern_sigaction(uap->sig, actp, oactp); 394 if (oactp && !error) { 395 error = copyout(oactp, uap->oact, sizeof(oact)); 396 } 397 return (error); 398 } 399 400 /* 401 * Initialize signal state for process 0; 402 * set to ignore signals that are ignored by default. 403 */ 404 void 405 siginit(struct proc *p) 406 { 407 int i; 408 409 for (i = 1; i <= NSIG; i++) 410 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 411 SIGADDSET(p->p_sigignore, i); 412 } 413 414 /* 415 * Reset signals for an exec of the specified process. 416 */ 417 void 418 execsigs(struct proc *p) 419 { 420 struct sigacts *ps = p->p_sigacts; 421 struct lwp *lp; 422 int sig; 423 424 lp = ONLY_LWP_IN_PROC(p); 425 426 /* 427 * Reset caught signals. Held signals remain held 428 * through p_sigmask (unless they were caught, 429 * and are now ignored by default). 430 */ 431 while (SIGNOTEMPTY(p->p_sigcatch)) { 432 sig = sig_ffs(&p->p_sigcatch); 433 SIGDELSET(p->p_sigcatch, sig); 434 if (sigprop(sig) & SA_IGNORE) { 435 if (sig != SIGCONT) 436 SIGADDSET(p->p_sigignore, sig); 437 SIGDELSET(p->p_siglist, sig); 438 SIGDELSET(lp->lwp_siglist, sig); 439 } 440 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 441 } 442 443 /* 444 * Reset stack state to the user stack. 445 * Clear set of signals caught on the signal stack. 446 */ 447 lp->lwp_sigstk.ss_flags = SS_DISABLE; 448 lp->lwp_sigstk.ss_size = 0; 449 lp->lwp_sigstk.ss_sp = 0; 450 lp->lwp_flag &= ~LWP_ALTSTACK; 451 /* 452 * Reset no zombies if child dies flag as Solaris does. 453 */ 454 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 455 } 456 457 /* 458 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 459 * 460 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 461 * p == curproc. 462 */ 463 int 464 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 465 { 466 struct thread *td = curthread; 467 struct lwp *lp = td->td_lwp; 468 struct proc *p = td->td_proc; 469 int error; 470 471 lwkt_gettoken(&p->p_token); 472 473 if (oset != NULL) 474 *oset = lp->lwp_sigmask; 475 476 error = 0; 477 if (set != NULL) { 478 switch (how) { 479 case SIG_BLOCK: 480 SIG_CANTMASK(*set); 481 SIGSETOR(lp->lwp_sigmask, *set); 482 break; 483 case SIG_UNBLOCK: 484 SIGSETNAND(lp->lwp_sigmask, *set); 485 break; 486 case SIG_SETMASK: 487 SIG_CANTMASK(*set); 488 lp->lwp_sigmask = *set; 489 break; 490 default: 491 error = EINVAL; 492 break; 493 } 494 } 495 496 lwkt_reltoken(&p->p_token); 497 498 return (error); 499 } 500 501 /* 502 * sigprocmask() 503 * 504 * MPSAFE 505 */ 506 int 507 sys_sigprocmask(struct sigprocmask_args *uap) 508 { 509 sigset_t set, oset; 510 sigset_t *setp, *osetp; 511 int error; 512 513 setp = (uap->set != NULL) ? &set : NULL; 514 osetp = (uap->oset != NULL) ? &oset : NULL; 515 if (setp) { 516 error = copyin(uap->set, setp, sizeof(set)); 517 if (error) 518 return (error); 519 } 520 error = kern_sigprocmask(uap->how, setp, osetp); 521 if (osetp && !error) { 522 error = copyout(osetp, uap->oset, sizeof(oset)); 523 } 524 return (error); 525 } 526 527 /* 528 * MPSAFE 529 */ 530 int 531 kern_sigpending(struct __sigset *set) 532 { 533 struct lwp *lp = curthread->td_lwp; 534 535 *set = lwp_sigpend(lp); 536 537 return (0); 538 } 539 540 /* 541 * MPSAFE 542 */ 543 int 544 sys_sigpending(struct sigpending_args *uap) 545 { 546 sigset_t set; 547 int error; 548 549 error = kern_sigpending(&set); 550 551 if (error == 0) 552 error = copyout(&set, uap->set, sizeof(set)); 553 return (error); 554 } 555 556 /* 557 * Suspend process until signal, providing mask to be set 558 * in the meantime. 559 * 560 * MPSAFE 561 */ 562 int 563 kern_sigsuspend(struct __sigset *set) 564 { 565 struct thread *td = curthread; 566 struct lwp *lp = td->td_lwp; 567 struct proc *p = td->td_proc; 568 struct sigacts *ps = p->p_sigacts; 569 570 /* 571 * When returning from sigsuspend, we want 572 * the old mask to be restored after the 573 * signal handler has finished. Thus, we 574 * save it here and mark the sigacts structure 575 * to indicate this. 576 */ 577 lp->lwp_oldsigmask = lp->lwp_sigmask; 578 lp->lwp_flag |= LWP_OLDMASK; 579 580 SIG_CANTMASK(*set); 581 lp->lwp_sigmask = *set; 582 while (tsleep(ps, PCATCH, "pause", 0) == 0) 583 /* void */; 584 /* always return EINTR rather than ERESTART... */ 585 return (EINTR); 586 } 587 588 /* 589 * Note nonstandard calling convention: libc stub passes mask, not 590 * pointer, to save a copyin. 591 * 592 * MPSAFE 593 */ 594 int 595 sys_sigsuspend(struct sigsuspend_args *uap) 596 { 597 sigset_t mask; 598 int error; 599 600 error = copyin(uap->sigmask, &mask, sizeof(mask)); 601 if (error) 602 return (error); 603 604 error = kern_sigsuspend(&mask); 605 606 return (error); 607 } 608 609 /* 610 * MPSAFE 611 */ 612 int 613 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 614 { 615 struct thread *td = curthread; 616 struct lwp *lp = td->td_lwp; 617 struct proc *p = td->td_proc; 618 619 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 620 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 621 622 if (oss) 623 *oss = lp->lwp_sigstk; 624 625 if (ss) { 626 if (ss->ss_flags & SS_DISABLE) { 627 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 628 return (EINVAL); 629 lp->lwp_flag &= ~LWP_ALTSTACK; 630 lp->lwp_sigstk.ss_flags = ss->ss_flags; 631 } else { 632 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 633 return (ENOMEM); 634 lp->lwp_flag |= LWP_ALTSTACK; 635 lp->lwp_sigstk = *ss; 636 } 637 } 638 639 return (0); 640 } 641 642 /* 643 * MPSAFE 644 */ 645 int 646 sys_sigaltstack(struct sigaltstack_args *uap) 647 { 648 stack_t ss, oss; 649 int error; 650 651 if (uap->ss) { 652 error = copyin(uap->ss, &ss, sizeof(ss)); 653 if (error) 654 return (error); 655 } 656 657 error = kern_sigaltstack(uap->ss ? &ss : NULL, 658 uap->oss ? &oss : NULL); 659 660 if (error == 0 && uap->oss) 661 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 662 return (error); 663 } 664 665 /* 666 * Common code for kill process group/broadcast kill. 667 * cp is calling process. 668 */ 669 struct killpg_info { 670 int nfound; 671 int sig; 672 }; 673 674 static int killpg_all_callback(struct proc *p, void *data); 675 676 static int 677 dokillpg(int sig, int pgid, int all) 678 { 679 struct killpg_info info; 680 struct proc *cp = curproc; 681 struct proc *p; 682 struct pgrp *pgrp; 683 684 info.nfound = 0; 685 info.sig = sig; 686 687 if (all) { 688 /* 689 * broadcast 690 */ 691 allproc_scan(killpg_all_callback, &info); 692 } else { 693 if (pgid == 0) { 694 /* 695 * zero pgid means send to my process group. 696 */ 697 pgrp = cp->p_pgrp; 698 pgref(pgrp); 699 } else { 700 pgrp = pgfind(pgid); 701 if (pgrp == NULL) 702 return (ESRCH); 703 } 704 705 /* 706 * Must interlock all signals against fork 707 */ 708 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 709 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 710 if (p->p_pid <= 1 || 711 p->p_stat == SZOMB || 712 (p->p_flag & P_SYSTEM) || 713 !CANSIGNAL(p, sig)) { 714 continue; 715 } 716 ++info.nfound; 717 if (sig) 718 ksignal(p, sig); 719 } 720 lockmgr(&pgrp->pg_lock, LK_RELEASE); 721 pgrel(pgrp); 722 } 723 return (info.nfound ? 0 : ESRCH); 724 } 725 726 static int 727 killpg_all_callback(struct proc *p, void *data) 728 { 729 struct killpg_info *info = data; 730 731 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 732 p == curproc || !CANSIGNAL(p, info->sig)) { 733 return (0); 734 } 735 ++info->nfound; 736 if (info->sig) 737 ksignal(p, info->sig); 738 return(0); 739 } 740 741 /* 742 * Send a general signal to a process or LWPs within that process. Note 743 * that new signals cannot be sent if a process is exiting. 744 * 745 * No requirements. 746 */ 747 int 748 kern_kill(int sig, pid_t pid, lwpid_t tid) 749 { 750 int t; 751 752 if ((u_int)sig > _SIG_MAXSIG) 753 return (EINVAL); 754 755 lwkt_gettoken(&proc_token); 756 757 if (pid > 0) { 758 struct proc *p; 759 struct lwp *lp = NULL; 760 761 /* kill single process */ 762 if ((p = pfind(pid)) == NULL) { 763 lwkt_reltoken(&proc_token); 764 return (ESRCH); 765 } 766 lwkt_gettoken(&p->p_token); 767 if (!CANSIGNAL(p, sig)) { 768 lwkt_reltoken(&p->p_token); 769 PRELE(p); 770 lwkt_reltoken(&proc_token); 771 return (EPERM); 772 } 773 774 /* 775 * NOP if the process is exiting. Note that lwpsignal() is 776 * called directly with P_WEXIT set to kill individual LWPs 777 * during exit, which is allowed. 778 */ 779 if (p->p_flag & P_WEXIT) { 780 lwkt_reltoken(&p->p_token); 781 PRELE(p); 782 lwkt_reltoken(&proc_token); 783 return (0); 784 } 785 if (tid != -1) { 786 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 787 if (lp == NULL) { 788 lwkt_reltoken(&p->p_token); 789 PRELE(p); 790 lwkt_reltoken(&proc_token); 791 return (ESRCH); 792 } 793 } 794 if (sig) 795 lwpsignal(p, lp, sig); 796 lwkt_reltoken(&p->p_token); 797 PRELE(p); 798 lwkt_reltoken(&proc_token); 799 return (0); 800 } 801 802 /* 803 * If we come here, pid is a special broadcast pid. 804 * This doesn't mix with a tid. 805 */ 806 if (tid != -1) { 807 lwkt_reltoken(&proc_token); 808 return (EINVAL); 809 } 810 switch (pid) { 811 case -1: /* broadcast signal */ 812 t = (dokillpg(sig, 0, 1)); 813 break; 814 case 0: /* signal own process group */ 815 t = (dokillpg(sig, 0, 0)); 816 break; 817 default: /* negative explicit process group */ 818 t = (dokillpg(sig, -pid, 0)); 819 break; 820 } 821 lwkt_reltoken(&proc_token); 822 return t; 823 } 824 825 int 826 sys_kill(struct kill_args *uap) 827 { 828 int error; 829 830 error = kern_kill(uap->signum, uap->pid, -1); 831 return (error); 832 } 833 834 int 835 sys_lwp_kill(struct lwp_kill_args *uap) 836 { 837 int error; 838 pid_t pid = uap->pid; 839 840 /* 841 * A tid is mandatory for lwp_kill(), otherwise 842 * you could simply use kill(). 843 */ 844 if (uap->tid == -1) 845 return (EINVAL); 846 847 /* 848 * To save on a getpid() function call for intra-process 849 * signals, pid == -1 means current process. 850 */ 851 if (pid == -1) 852 pid = curproc->p_pid; 853 854 error = kern_kill(uap->signum, pid, uap->tid); 855 return (error); 856 } 857 858 /* 859 * Send a signal to a process group. 860 */ 861 void 862 gsignal(int pgid, int sig) 863 { 864 struct pgrp *pgrp; 865 866 if (pgid && (pgrp = pgfind(pgid))) 867 pgsignal(pgrp, sig, 0); 868 } 869 870 /* 871 * Send a signal to a process group. If checktty is 1, 872 * limit to members which have a controlling terminal. 873 * 874 * pg_lock interlocks against a fork that might be in progress, to 875 * ensure that the new child process picks up the signal. 876 */ 877 void 878 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 879 { 880 struct proc *p; 881 882 /* 883 * Must interlock all signals against fork 884 */ 885 if (pgrp) { 886 pgref(pgrp); 887 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 888 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 889 if (checkctty == 0 || p->p_flag & P_CONTROLT) 890 ksignal(p, sig); 891 } 892 lockmgr(&pgrp->pg_lock, LK_RELEASE); 893 pgrel(pgrp); 894 } 895 } 896 897 /* 898 * Send a signal caused by a trap to the current lwp. If it will be caught 899 * immediately, deliver it with correct code. Otherwise, post it normally. 900 * 901 * These signals may ONLY be delivered to the specified lwp and may never 902 * be delivered to the process generically. 903 */ 904 void 905 trapsignal(struct lwp *lp, int sig, u_long code) 906 { 907 struct proc *p = lp->lwp_proc; 908 struct sigacts *ps = p->p_sigacts; 909 910 /* 911 * If we are a virtual kernel running an emulated user process 912 * context, switch back to the virtual kernel context before 913 * trying to post the signal. 914 */ 915 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 916 struct trapframe *tf = lp->lwp_md.md_regs; 917 tf->tf_trapno = 0; 918 vkernel_trap(lp, tf); 919 } 920 921 922 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 923 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 924 lp->lwp_ru.ru_nsignals++; 925 #ifdef KTRACE 926 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 927 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 928 &lp->lwp_sigmask, code); 929 #endif 930 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 931 &lp->lwp_sigmask, code); 932 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 933 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 934 SIGADDSET(lp->lwp_sigmask, sig); 935 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 936 /* 937 * See kern_sigaction() for origin of this code. 938 */ 939 SIGDELSET(p->p_sigcatch, sig); 940 if (sig != SIGCONT && 941 sigprop(sig) & SA_IGNORE) 942 SIGADDSET(p->p_sigignore, sig); 943 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 944 } 945 } else { 946 lp->lwp_code = code; /* XXX for core dump/debugger */ 947 lp->lwp_sig = sig; /* XXX to verify code */ 948 lwpsignal(p, lp, sig); 949 } 950 } 951 952 /* 953 * Find a suitable lwp to deliver the signal to. Returns NULL if all 954 * lwps hold the signal blocked. 955 * 956 * Caller must hold p->p_token. 957 * 958 * Returns a lp or NULL. If non-NULL the lp is held and its token is 959 * acquired. 960 */ 961 static struct lwp * 962 find_lwp_for_signal(struct proc *p, int sig) 963 { 964 struct lwp *lp; 965 struct lwp *run, *sleep, *stop; 966 967 /* 968 * If the running/preempted thread belongs to the proc to which 969 * the signal is being delivered and this thread does not block 970 * the signal, then we can avoid a context switch by delivering 971 * the signal to this thread, because it will return to userland 972 * soon anyways. 973 */ 974 lp = lwkt_preempted_proc(); 975 if (lp != NULL && lp->lwp_proc == p) { 976 LWPHOLD(lp); 977 lwkt_gettoken(&lp->lwp_token); 978 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 979 /* return w/ token held */ 980 return (lp); 981 } 982 lwkt_reltoken(&lp->lwp_token); 983 LWPRELE(lp); 984 } 985 986 run = sleep = stop = NULL; 987 FOREACH_LWP_IN_PROC(lp, p) { 988 /* 989 * If the signal is being blocked by the lwp, then this 990 * lwp is not eligible for receiving the signal. 991 */ 992 LWPHOLD(lp); 993 lwkt_gettoken(&lp->lwp_token); 994 995 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 996 lwkt_reltoken(&lp->lwp_token); 997 LWPRELE(lp); 998 continue; 999 } 1000 1001 switch (lp->lwp_stat) { 1002 case LSRUN: 1003 if (sleep) { 1004 lwkt_token_swap(); 1005 lwkt_reltoken(&sleep->lwp_token); 1006 LWPRELE(sleep); 1007 sleep = NULL; 1008 run = lp; 1009 } else if (stop) { 1010 lwkt_token_swap(); 1011 lwkt_reltoken(&stop->lwp_token); 1012 LWPRELE(stop); 1013 stop = NULL; 1014 run = lp; 1015 } else { 1016 run = lp; 1017 } 1018 break; 1019 case LSSLEEP: 1020 if (lp->lwp_flag & LWP_SINTR) { 1021 if (sleep) { 1022 lwkt_reltoken(&lp->lwp_token); 1023 LWPRELE(lp); 1024 } else if (stop) { 1025 lwkt_token_swap(); 1026 lwkt_reltoken(&stop->lwp_token); 1027 LWPRELE(stop); 1028 stop = NULL; 1029 sleep = lp; 1030 } else { 1031 sleep = lp; 1032 } 1033 } else { 1034 lwkt_reltoken(&lp->lwp_token); 1035 LWPRELE(lp); 1036 } 1037 break; 1038 case LSSTOP: 1039 if (sleep) { 1040 lwkt_reltoken(&lp->lwp_token); 1041 LWPRELE(lp); 1042 } else if (stop) { 1043 lwkt_reltoken(&lp->lwp_token); 1044 LWPRELE(lp); 1045 } else { 1046 stop = lp; 1047 } 1048 break; 1049 } 1050 if (run) 1051 break; 1052 } 1053 1054 if (run != NULL) 1055 return (run); 1056 else if (sleep != NULL) 1057 return (sleep); 1058 else 1059 return (stop); 1060 } 1061 1062 /* 1063 * Send the signal to the process. If the signal has an action, the action 1064 * is usually performed by the target process rather than the caller; we add 1065 * the signal to the set of pending signals for the process. 1066 * 1067 * Exceptions: 1068 * o When a stop signal is sent to a sleeping process that takes the 1069 * default action, the process is stopped without awakening it. 1070 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1071 * regardless of the signal action (eg, blocked or ignored). 1072 * 1073 * Other ignored signals are discarded immediately. 1074 * 1075 * If the caller wishes to call this function from a hard code section the 1076 * caller must already hold p->p_token (see kern_clock.c). 1077 * 1078 * No requirements. 1079 */ 1080 void 1081 ksignal(struct proc *p, int sig) 1082 { 1083 lwpsignal(p, NULL, sig); 1084 } 1085 1086 /* 1087 * The core for ksignal. lp may be NULL, then a suitable thread 1088 * will be chosen. If not, lp MUST be a member of p. 1089 * 1090 * If the caller wishes to call this function from a hard code section the 1091 * caller must already hold p->p_token. 1092 * 1093 * No requirements. 1094 */ 1095 void 1096 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1097 { 1098 struct proc *q; 1099 sig_t action; 1100 int prop; 1101 1102 if (sig > _SIG_MAXSIG || sig <= 0) { 1103 kprintf("lwpsignal: signal %d\n", sig); 1104 panic("lwpsignal signal number"); 1105 } 1106 1107 KKASSERT(lp == NULL || lp->lwp_proc == p); 1108 1109 PHOLD(p); 1110 lwkt_gettoken(&p->p_token); 1111 if (lp) { 1112 LWPHOLD(lp); 1113 lwkt_gettoken(&lp->lwp_token); 1114 } 1115 1116 prop = sigprop(sig); 1117 1118 /* 1119 * If proc is traced, always give parent a chance; 1120 * if signal event is tracked by procfs, give *that* 1121 * a chance, as well. 1122 */ 1123 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1124 action = SIG_DFL; 1125 } else { 1126 /* 1127 * Do not try to deliver signals to an exiting lwp. Note 1128 * that we must still deliver the signal if P_WEXIT is set 1129 * in the process flags. 1130 */ 1131 if (lp && (lp->lwp_flag & LWP_WEXIT)) { 1132 if (lp) { 1133 lwkt_reltoken(&lp->lwp_token); 1134 LWPRELE(lp); 1135 } 1136 lwkt_reltoken(&p->p_token); 1137 PRELE(p); 1138 return; 1139 } 1140 1141 /* 1142 * If the signal is being ignored, then we forget about 1143 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1144 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1145 */ 1146 if (SIGISMEMBER(p->p_sigignore, sig)) { 1147 /* 1148 * Even if a signal is set SIG_IGN, it may still be 1149 * lurking in a kqueue. 1150 */ 1151 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1152 if (lp) { 1153 lwkt_reltoken(&lp->lwp_token); 1154 LWPRELE(lp); 1155 } 1156 lwkt_reltoken(&p->p_token); 1157 PRELE(p); 1158 return; 1159 } 1160 if (SIGISMEMBER(p->p_sigcatch, sig)) 1161 action = SIG_CATCH; 1162 else 1163 action = SIG_DFL; 1164 } 1165 1166 /* 1167 * If continuing, clear any pending STOP signals. 1168 */ 1169 if (prop & SA_CONT) 1170 SIG_STOPSIGMASK(p->p_siglist); 1171 1172 if (prop & SA_STOP) { 1173 /* 1174 * If sending a tty stop signal to a member of an orphaned 1175 * process group, discard the signal here if the action 1176 * is default; don't stop the process below if sleeping, 1177 * and don't clear any pending SIGCONT. 1178 */ 1179 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1180 action == SIG_DFL) { 1181 lwkt_reltoken(&p->p_token); 1182 PRELE(p); 1183 return; 1184 } 1185 SIG_CONTSIGMASK(p->p_siglist); 1186 p->p_flag &= ~P_CONTINUED; 1187 } 1188 1189 crit_enter(); 1190 1191 if (p->p_stat == SSTOP) { 1192 /* 1193 * Nobody can handle this signal, add it to the lwp or 1194 * process pending list 1195 */ 1196 if (lp) 1197 SIGADDSET(lp->lwp_siglist, sig); 1198 else 1199 SIGADDSET(p->p_siglist, sig); 1200 1201 /* 1202 * If the process is stopped and is being traced, then no 1203 * further action is necessary. 1204 */ 1205 if (p->p_flag & P_TRACED) 1206 goto out; 1207 1208 /* 1209 * If the process is stopped and receives a KILL signal, 1210 * make the process runnable. 1211 */ 1212 if (sig == SIGKILL) { 1213 proc_unstop(p); 1214 goto active_process; 1215 } 1216 1217 /* 1218 * If the process is stopped and receives a CONT signal, 1219 * then try to make the process runnable again. 1220 */ 1221 if (prop & SA_CONT) { 1222 /* 1223 * If SIGCONT is default (or ignored), we continue the 1224 * process but don't leave the signal in p_siglist, as 1225 * it has no further action. If SIGCONT is held, we 1226 * continue the process and leave the signal in 1227 * p_siglist. If the process catches SIGCONT, let it 1228 * handle the signal itself. 1229 * 1230 * XXX what if the signal is being held blocked? 1231 * 1232 * Token required to interlock kern_wait(). 1233 * Reparenting can also cause a race so we have to 1234 * hold (q). 1235 */ 1236 q = p->p_pptr; 1237 PHOLD(q); 1238 lwkt_gettoken(&q->p_token); 1239 p->p_flag |= P_CONTINUED; 1240 wakeup(q); 1241 if (action == SIG_DFL) 1242 SIGDELSET(p->p_siglist, sig); 1243 proc_unstop(p); 1244 lwkt_reltoken(&q->p_token); 1245 PRELE(q); 1246 if (action == SIG_CATCH) 1247 goto active_process; 1248 goto out; 1249 } 1250 1251 /* 1252 * If the process is stopped and receives another STOP 1253 * signal, we do not need to stop it again. If we did 1254 * the shell could get confused. 1255 * 1256 * However, if the current/preempted lwp is part of the 1257 * process receiving the signal, we need to keep it, 1258 * so that this lwp can stop in issignal() later, as 1259 * we don't want to wait until it reaches userret! 1260 */ 1261 if (prop & SA_STOP) { 1262 if (lwkt_preempted_proc() == NULL || 1263 lwkt_preempted_proc()->lwp_proc != p) 1264 SIGDELSET(p->p_siglist, sig); 1265 } 1266 1267 /* 1268 * Otherwise the process is stopped and it received some 1269 * signal, which does not change its stopped state. 1270 * 1271 * We have to select one thread to set LWP_BREAKTSLEEP, 1272 * so that the current signal will break the sleep 1273 * as soon as a SA_CONT signal will unstop the process. 1274 */ 1275 if (lp == NULL) { 1276 /* NOTE: returns lp w/ token held */ 1277 lp = find_lwp_for_signal(p, sig); 1278 } 1279 if (lp != NULL && 1280 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1281 lp->lwp_flag |= LWP_BREAKTSLEEP; 1282 goto out; 1283 1284 /* NOTREACHED */ 1285 } 1286 /* else not stopped */ 1287 active_process: 1288 1289 /* 1290 * Never deliver a lwp-specific signal to a random lwp. 1291 */ 1292 if (lp == NULL) { 1293 /* NOTE: returns lp w/ token held */ 1294 lp = find_lwp_for_signal(p, sig); 1295 if (lp) { 1296 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1297 lwkt_reltoken(&lp->lwp_token); 1298 LWPRELE(lp); 1299 lp = NULL; 1300 } 1301 } 1302 } 1303 1304 /* 1305 * Deliver to the process generically if (1) the signal is being 1306 * sent to any thread or (2) we could not find a thread to deliver 1307 * it to. 1308 */ 1309 if (lp == NULL) { 1310 SIGADDSET(p->p_siglist, sig); 1311 goto out; 1312 } 1313 1314 /* 1315 * Deliver to a specific LWP whether it masks it or not. It will 1316 * not be dispatched if masked but we must still deliver it. 1317 */ 1318 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1319 (p->p_flag & P_TRACED) == 0) { 1320 p->p_nice = NZERO; 1321 } 1322 1323 /* 1324 * If the process receives a STOP signal which indeed needs to 1325 * stop the process, do so. If the process chose to catch the 1326 * signal, it will be treated like any other signal. 1327 */ 1328 if ((prop & SA_STOP) && action == SIG_DFL) { 1329 /* 1330 * If a child holding parent blocked, stopping 1331 * could cause deadlock. Take no action at this 1332 * time. 1333 */ 1334 if (p->p_flag & P_PPWAIT) { 1335 SIGADDSET(p->p_siglist, sig); 1336 goto out; 1337 } 1338 1339 /* 1340 * Do not actually try to manipulate the process, but simply 1341 * stop it. Lwps will stop as soon as they safely can. 1342 */ 1343 p->p_xstat = sig; 1344 proc_stop(p); 1345 goto out; 1346 } 1347 1348 /* 1349 * If it is a CONT signal with default action, just ignore it. 1350 */ 1351 if ((prop & SA_CONT) && action == SIG_DFL) 1352 goto out; 1353 1354 /* 1355 * Mark signal pending at this specific thread. 1356 */ 1357 SIGADDSET(lp->lwp_siglist, sig); 1358 1359 lwp_signotify(lp); 1360 1361 out: 1362 if (lp) { 1363 lwkt_reltoken(&lp->lwp_token); 1364 LWPRELE(lp); 1365 } 1366 lwkt_reltoken(&p->p_token); 1367 PRELE(p); 1368 crit_exit(); 1369 } 1370 1371 /* 1372 * p->p_token must be held 1373 */ 1374 static void 1375 lwp_signotify(struct lwp *lp) 1376 { 1377 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1378 crit_enter(); 1379 1380 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1381 /* 1382 * Thread is in tsleep. 1383 */ 1384 1385 /* 1386 * If the thread is sleeping uninterruptibly 1387 * we can't interrupt the sleep... the signal will 1388 * be noticed when the lwp returns through 1389 * trap() or syscall(). 1390 * 1391 * Otherwise the signal can interrupt the sleep. 1392 * 1393 * If the process is traced, the lwp will handle the 1394 * tracing in issignal() when it returns to userland. 1395 */ 1396 if (lp->lwp_flag & LWP_SINTR) { 1397 /* 1398 * Make runnable and break out of any tsleep as well. 1399 */ 1400 lp->lwp_flag |= LWP_BREAKTSLEEP; 1401 setrunnable(lp); 1402 } 1403 } else { 1404 /* 1405 * Otherwise the thread is running 1406 * 1407 * LSRUN does nothing with the signal, other than kicking 1408 * ourselves if we are running. 1409 * SZOMB and SIDL mean that it will either never be noticed, 1410 * or noticed very soon. 1411 * 1412 * Note that lwp_thread may be NULL or may not be completely 1413 * initialized if the process is in the SIDL or SZOMB state. 1414 * 1415 * For SMP we may have to forward the request to another cpu. 1416 * YYY the MP lock prevents the target process from moving 1417 * to another cpu, see kern/kern_switch.c 1418 * 1419 * If the target thread is waiting on its message port, 1420 * wakeup the target thread so it can check (or ignore) 1421 * the new signal. YYY needs cleanup. 1422 */ 1423 if (lp == lwkt_preempted_proc()) { 1424 signotify(); 1425 } else if (lp->lwp_stat == LSRUN) { 1426 struct thread *td = lp->lwp_thread; 1427 struct proc *p __debugvar = lp->lwp_proc; 1428 1429 KASSERT(td != NULL, 1430 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1431 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1432 p->p_flag, lp->lwp_flag)); 1433 1434 /* 1435 * To prevent a MP race with TDF_SINTR we must 1436 * schedule the thread on the correct cpu. 1437 */ 1438 #ifdef SMP 1439 if (td->td_gd != mycpu) { 1440 LWPHOLD(lp); 1441 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1442 } else 1443 #endif 1444 if (td->td_flags & TDF_SINTR) 1445 lwkt_schedule(td); 1446 } 1447 } 1448 crit_exit(); 1449 } 1450 1451 #ifdef SMP 1452 1453 /* 1454 * This function is called via an IPI. We will be in a critical section but 1455 * the MP lock will NOT be held. The passed lp will be held. 1456 * 1457 * We must essentially repeat the code at the end of lwp_signotify(), 1458 * in particular rechecking all races. If we are still not on the 1459 * correct cpu we leave the lwp ref intact and continue the chase. 1460 * 1461 * XXX this may still not be entirely correct, since we are checking 1462 * lwp_stat asynchronously. 1463 */ 1464 static void 1465 signotify_remote(void *arg) 1466 { 1467 struct lwp *lp = arg; 1468 thread_t td; 1469 1470 if (lp == lwkt_preempted_proc()) { 1471 signotify(); 1472 } else if (lp->lwp_stat == LSRUN) { 1473 /* 1474 * To prevent a MP race with TDF_SINTR we must 1475 * schedule the thread on the correct cpu. 1476 */ 1477 td = lp->lwp_thread; 1478 if (td->td_gd != mycpu) { 1479 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1480 return; 1481 /* NOT REACHED */ 1482 } 1483 if (td->td_flags & TDF_SINTR) 1484 lwkt_schedule(td); 1485 } 1486 LWPRELE(lp); 1487 } 1488 1489 #endif 1490 1491 /* 1492 * Caller must hold p->p_token 1493 */ 1494 void 1495 proc_stop(struct proc *p) 1496 { 1497 struct proc *q; 1498 struct lwp *lp; 1499 1500 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1501 crit_enter(); 1502 1503 /* If somebody raced us, be happy with it */ 1504 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1505 crit_exit(); 1506 return; 1507 } 1508 p->p_stat = SSTOP; 1509 1510 FOREACH_LWP_IN_PROC(lp, p) { 1511 LWPHOLD(lp); 1512 lwkt_gettoken(&lp->lwp_token); 1513 1514 switch (lp->lwp_stat) { 1515 case LSSTOP: 1516 /* 1517 * Do nothing, we are already counted in 1518 * p_nstopped. 1519 */ 1520 break; 1521 1522 case LSSLEEP: 1523 /* 1524 * We're sleeping, but we will stop before 1525 * returning to userspace, so count us 1526 * as stopped as well. We set LWP_WSTOP 1527 * to signal the lwp that it should not 1528 * increase p_nstopped when reaching tstop(). 1529 */ 1530 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1531 lp->lwp_flag |= LWP_WSTOP; 1532 ++p->p_nstopped; 1533 } 1534 break; 1535 1536 case LSRUN: 1537 /* 1538 * We might notify ourself, but that's not 1539 * a problem. 1540 */ 1541 lwp_signotify(lp); 1542 break; 1543 } 1544 lwkt_reltoken(&lp->lwp_token); 1545 LWPRELE(lp); 1546 } 1547 1548 if (p->p_nstopped == p->p_nthreads) { 1549 /* 1550 * Token required to interlock kern_wait(). Reparenting can 1551 * also cause a race so we have to hold (q). 1552 */ 1553 q = p->p_pptr; 1554 PHOLD(q); 1555 lwkt_gettoken(&q->p_token); 1556 p->p_flag &= ~P_WAITED; 1557 wakeup(q); 1558 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1559 ksignal(p->p_pptr, SIGCHLD); 1560 lwkt_reltoken(&q->p_token); 1561 PRELE(q); 1562 } 1563 crit_exit(); 1564 } 1565 1566 /* 1567 * Caller must hold proc_token 1568 */ 1569 void 1570 proc_unstop(struct proc *p) 1571 { 1572 struct lwp *lp; 1573 1574 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1575 crit_enter(); 1576 1577 if (p->p_stat != SSTOP) { 1578 crit_exit(); 1579 return; 1580 } 1581 1582 p->p_stat = SACTIVE; 1583 1584 FOREACH_LWP_IN_PROC(lp, p) { 1585 LWPHOLD(lp); 1586 lwkt_gettoken(&lp->lwp_token); 1587 1588 switch (lp->lwp_stat) { 1589 case LSRUN: 1590 /* 1591 * Uh? Not stopped? Well, I guess that's okay. 1592 */ 1593 if (bootverbose) 1594 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1595 p->p_pid, lp->lwp_tid); 1596 break; 1597 1598 case LSSLEEP: 1599 /* 1600 * Still sleeping. Don't bother waking it up. 1601 * However, if this thread was counted as 1602 * stopped, undo this. 1603 * 1604 * Nevertheless we call setrunnable() so that it 1605 * will wake up in case a signal or timeout arrived 1606 * in the meantime. 1607 */ 1608 if (lp->lwp_flag & LWP_WSTOP) { 1609 lp->lwp_flag &= ~LWP_WSTOP; 1610 --p->p_nstopped; 1611 } else { 1612 if (bootverbose) 1613 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1614 p->p_pid, lp->lwp_tid); 1615 } 1616 /* FALLTHROUGH */ 1617 1618 case LSSTOP: 1619 setrunnable(lp); 1620 break; 1621 1622 } 1623 lwkt_reltoken(&lp->lwp_token); 1624 LWPRELE(lp); 1625 } 1626 crit_exit(); 1627 } 1628 1629 /* 1630 * No requirements. 1631 */ 1632 static int 1633 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1634 { 1635 sigset_t savedmask, set; 1636 struct proc *p = curproc; 1637 struct lwp *lp = curthread->td_lwp; 1638 int error, sig, hz, timevalid = 0; 1639 struct timespec rts, ets, ts; 1640 struct timeval tv; 1641 1642 error = 0; 1643 sig = 0; 1644 ets.tv_sec = 0; /* silence compiler warning */ 1645 ets.tv_nsec = 0; /* silence compiler warning */ 1646 SIG_CANTMASK(waitset); 1647 savedmask = lp->lwp_sigmask; 1648 1649 if (timeout) { 1650 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1651 timeout->tv_nsec < 1000000000) { 1652 timevalid = 1; 1653 getnanouptime(&rts); 1654 ets = rts; 1655 timespecadd(&ets, timeout); 1656 } 1657 } 1658 1659 for (;;) { 1660 set = lwp_sigpend(lp); 1661 SIGSETAND(set, waitset); 1662 if ((sig = sig_ffs(&set)) != 0) { 1663 SIGFILLSET(lp->lwp_sigmask); 1664 SIGDELSET(lp->lwp_sigmask, sig); 1665 SIG_CANTMASK(lp->lwp_sigmask); 1666 sig = issignal(lp, 1); 1667 /* 1668 * It may be a STOP signal, in the case, issignal 1669 * returns 0, because we may stop there, and new 1670 * signal can come in, we should restart if we got 1671 * nothing. 1672 */ 1673 if (sig == 0) 1674 continue; 1675 else 1676 break; 1677 } 1678 1679 /* 1680 * Previous checking got nothing, and we retried but still 1681 * got nothing, we should return the error status. 1682 */ 1683 if (error) 1684 break; 1685 1686 /* 1687 * POSIX says this must be checked after looking for pending 1688 * signals. 1689 */ 1690 if (timeout) { 1691 if (timevalid == 0) { 1692 error = EINVAL; 1693 break; 1694 } 1695 getnanouptime(&rts); 1696 if (timespeccmp(&rts, &ets, >=)) { 1697 error = EAGAIN; 1698 break; 1699 } 1700 ts = ets; 1701 timespecsub(&ts, &rts); 1702 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1703 hz = tvtohz_high(&tv); 1704 } else { 1705 hz = 0; 1706 } 1707 1708 lp->lwp_sigmask = savedmask; 1709 SIGSETNAND(lp->lwp_sigmask, waitset); 1710 /* 1711 * We won't ever be woken up. Instead, our sleep will 1712 * be broken in lwpsignal(). 1713 */ 1714 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1715 if (timeout) { 1716 if (error == ERESTART) { 1717 /* can not restart a timeout wait. */ 1718 error = EINTR; 1719 } else if (error == EAGAIN) { 1720 /* will calculate timeout by ourself. */ 1721 error = 0; 1722 } 1723 } 1724 /* Retry ... */ 1725 } 1726 1727 lp->lwp_sigmask = savedmask; 1728 if (sig) { 1729 error = 0; 1730 bzero(info, sizeof(*info)); 1731 info->si_signo = sig; 1732 lwp_delsig(lp, sig); /* take the signal! */ 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_flag & 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_flag & 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 lwp_delsig(lp, sig); 1892 continue; 1893 } 1894 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1895 /* 1896 * If traced, always stop, and stay stopped until 1897 * released by the parent. 1898 * 1899 * NOTE: SSTOP may get cleared during the loop, 1900 * but we do not re-notify the parent if we have 1901 * to loop several times waiting for the parent 1902 * to let us continue. 1903 * 1904 * XXX not sure if this is still true 1905 */ 1906 p->p_xstat = sig; 1907 proc_stop(p); 1908 do { 1909 tstop(); 1910 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1911 1912 /* 1913 * If parent wants us to take the signal, 1914 * then it will leave it in p->p_xstat; 1915 * otherwise we just look for signals again. 1916 */ 1917 lwp_delsig(lp, sig); /* clear old signal */ 1918 sig = p->p_xstat; 1919 if (sig == 0) 1920 continue; 1921 1922 /* 1923 * Put the new signal into p_siglist. If the 1924 * signal is being masked, look for other signals. 1925 * 1926 * XXX lwp might need a call to ksignal() 1927 */ 1928 SIGADDSET(p->p_siglist, sig); 1929 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1930 continue; 1931 1932 /* 1933 * If the traced bit got turned off, go back up 1934 * to the top to rescan signals. This ensures 1935 * that p_sig* and ps_sigact are consistent. 1936 */ 1937 if ((p->p_flag & P_TRACED) == 0) 1938 continue; 1939 } 1940 1941 prop = sigprop(sig); 1942 1943 /* 1944 * Decide whether the signal should be returned. 1945 * Return the signal's number, or fall through 1946 * to clear it from the pending mask. 1947 */ 1948 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1949 case (intptr_t)SIG_DFL: 1950 /* 1951 * Don't take default actions on system processes. 1952 */ 1953 if (p->p_pid <= 1) { 1954 #ifdef DIAGNOSTIC 1955 /* 1956 * Are you sure you want to ignore SIGSEGV 1957 * in init? XXX 1958 */ 1959 kprintf("Process (pid %lu) got signal %d\n", 1960 (u_long)p->p_pid, sig); 1961 #endif 1962 break; /* == ignore */ 1963 } 1964 1965 /* 1966 * Handle the in-kernel checkpoint action 1967 */ 1968 if (prop & SA_CKPT) { 1969 checkpoint_signal_handler(lp); 1970 break; 1971 } 1972 1973 /* 1974 * If there is a pending stop signal to process 1975 * with default action, stop here, 1976 * then clear the signal. However, 1977 * if process is member of an orphaned 1978 * process group, ignore tty stop signals. 1979 */ 1980 if (prop & SA_STOP) { 1981 if (p->p_flag & P_TRACED || 1982 (p->p_pgrp->pg_jobc == 0 && 1983 prop & SA_TTYSTOP)) 1984 break; /* == ignore */ 1985 p->p_xstat = sig; 1986 proc_stop(p); 1987 tstop(); 1988 break; 1989 } else if (prop & SA_IGNORE) { 1990 /* 1991 * Except for SIGCONT, shouldn't get here. 1992 * Default action is to ignore; drop it. 1993 */ 1994 break; /* == ignore */ 1995 } else { 1996 lwkt_reltoken(&p->p_token); 1997 return (sig); 1998 } 1999 2000 /*NOTREACHED*/ 2001 2002 case (intptr_t)SIG_IGN: 2003 /* 2004 * Masking above should prevent us ever trying 2005 * to take action on an ignored signal other 2006 * than SIGCONT, unless process is traced. 2007 */ 2008 if ((prop & SA_CONT) == 0 && 2009 (p->p_flag & P_TRACED) == 0) 2010 kprintf("issignal\n"); 2011 break; /* == ignore */ 2012 2013 default: 2014 /* 2015 * This signal has an action, let 2016 * postsig() process it. 2017 */ 2018 lwkt_reltoken(&p->p_token); 2019 return (sig); 2020 } 2021 lwp_delsig(lp, sig); /* take the signal! */ 2022 } 2023 /* NOTREACHED */ 2024 } 2025 2026 /* 2027 * Take the action for the specified signal 2028 * from the current set of pending signals. 2029 * 2030 * Caller must hold p->p_token 2031 */ 2032 void 2033 postsig(int sig) 2034 { 2035 struct lwp *lp = curthread->td_lwp; 2036 struct proc *p = lp->lwp_proc; 2037 struct sigacts *ps = p->p_sigacts; 2038 sig_t action; 2039 sigset_t returnmask; 2040 int code; 2041 2042 KASSERT(sig != 0, ("postsig")); 2043 2044 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2045 2046 /* 2047 * If we are a virtual kernel running an emulated user process 2048 * context, switch back to the virtual kernel context before 2049 * trying to post the signal. 2050 */ 2051 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2052 struct trapframe *tf = lp->lwp_md.md_regs; 2053 tf->tf_trapno = 0; 2054 vkernel_trap(lp, tf); 2055 } 2056 2057 lwp_delsig(lp, sig); 2058 action = ps->ps_sigact[_SIG_IDX(sig)]; 2059 #ifdef KTRACE 2060 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2061 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 2062 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2063 #endif 2064 STOPEVENT(p, S_SIG, sig); 2065 2066 if (action == SIG_DFL) { 2067 /* 2068 * Default action, where the default is to kill 2069 * the process. (Other cases were ignored above.) 2070 */ 2071 sigexit(lp, sig); 2072 /* NOTREACHED */ 2073 } else { 2074 /* 2075 * If we get here, the signal must be caught. 2076 */ 2077 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2078 ("postsig action")); 2079 2080 crit_enter(); 2081 2082 /* 2083 * Reset the signal handler if asked to 2084 */ 2085 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2086 /* 2087 * See kern_sigaction() for origin of this code. 2088 */ 2089 SIGDELSET(p->p_sigcatch, sig); 2090 if (sig != SIGCONT && 2091 sigprop(sig) & SA_IGNORE) 2092 SIGADDSET(p->p_sigignore, sig); 2093 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2094 } 2095 2096 /* 2097 * Handle the mailbox case. Copyout to the appropriate 2098 * location but do not generate a signal frame. The system 2099 * call simply returns EINTR and the user is responsible for 2100 * polling the mailbox. 2101 */ 2102 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 2103 int sig_copy = sig; 2104 copyout(&sig_copy, (void *)action, sizeof(int)); 2105 lwkt_gettoken(&curproc->p_token); 2106 curproc->p_flag |= P_MAILBOX; 2107 lwkt_reltoken(&curproc->p_token); 2108 crit_exit(); 2109 goto done; 2110 } 2111 2112 /* 2113 * Set the signal mask and calculate the mask to restore 2114 * when the signal function returns. 2115 * 2116 * Special case: user has done a sigsuspend. Here the 2117 * current mask is not of interest, but rather the 2118 * mask from before the sigsuspend is what we want 2119 * restored after the signal processing is completed. 2120 */ 2121 if (lp->lwp_flag & LWP_OLDMASK) { 2122 returnmask = lp->lwp_oldsigmask; 2123 lp->lwp_flag &= ~LWP_OLDMASK; 2124 } else { 2125 returnmask = lp->lwp_sigmask; 2126 } 2127 2128 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2129 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2130 SIGADDSET(lp->lwp_sigmask, sig); 2131 2132 crit_exit(); 2133 lp->lwp_ru.ru_nsignals++; 2134 if (lp->lwp_sig != sig) { 2135 code = 0; 2136 } else { 2137 code = lp->lwp_code; 2138 lp->lwp_code = 0; 2139 lp->lwp_sig = 0; 2140 } 2141 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2142 } 2143 done: 2144 ; 2145 } 2146 2147 /* 2148 * Kill the current process for stated reason. 2149 */ 2150 void 2151 killproc(struct proc *p, char *why) 2152 { 2153 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2154 p->p_pid, p->p_comm, 2155 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2156 ksignal(p, SIGKILL); 2157 } 2158 2159 /* 2160 * Force the current process to exit with the specified signal, dumping core 2161 * if appropriate. We bypass the normal tests for masked and caught signals, 2162 * allowing unrecoverable failures to terminate the process without changing 2163 * signal state. Mark the accounting record with the signal termination. 2164 * If dumping core, save the signal number for the debugger. Calls exit and 2165 * does not return. 2166 * 2167 * This routine does not return. 2168 */ 2169 void 2170 sigexit(struct lwp *lp, int sig) 2171 { 2172 struct proc *p = lp->lwp_proc; 2173 2174 lwkt_gettoken(&p->p_token); 2175 p->p_acflag |= AXSIG; 2176 if (sigprop(sig) & SA_CORE) { 2177 lp->lwp_sig = sig; 2178 /* 2179 * Log signals which would cause core dumps 2180 * (Log as LOG_INFO to appease those who don't want 2181 * these messages.) 2182 * XXX : Todo, as well as euid, write out ruid too 2183 */ 2184 if (coredump(lp, sig) == 0) 2185 sig |= WCOREFLAG; 2186 if (kern_logsigexit) 2187 log(LOG_INFO, 2188 "pid %d (%s), uid %d: exited on signal %d%s\n", 2189 p->p_pid, p->p_comm, 2190 p->p_ucred ? p->p_ucred->cr_uid : -1, 2191 sig &~ WCOREFLAG, 2192 sig & WCOREFLAG ? " (core dumped)" : ""); 2193 } 2194 lwkt_reltoken(&p->p_token); 2195 exit1(W_EXITCODE(0, sig)); 2196 /* NOTREACHED */ 2197 } 2198 2199 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2200 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2201 sizeof(corefilename), "process corefile name format string"); 2202 2203 /* 2204 * expand_name(name, uid, pid) 2205 * Expand the name described in corefilename, using name, uid, and pid. 2206 * corefilename is a kprintf-like string, with three format specifiers: 2207 * %N name of process ("name") 2208 * %P process id (pid) 2209 * %U user id (uid) 2210 * For example, "%N.core" is the default; they can be disabled completely 2211 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2212 * This is controlled by the sysctl variable kern.corefile (see above). 2213 */ 2214 2215 static char * 2216 expand_name(const char *name, uid_t uid, pid_t pid) 2217 { 2218 char *temp; 2219 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2220 int i, n; 2221 char *format = corefilename; 2222 size_t namelen; 2223 2224 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2225 if (temp == NULL) 2226 return NULL; 2227 namelen = strlen(name); 2228 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2229 int l; 2230 switch (format[i]) { 2231 case '%': /* Format character */ 2232 i++; 2233 switch (format[i]) { 2234 case '%': 2235 temp[n++] = '%'; 2236 break; 2237 case 'N': /* process name */ 2238 if ((n + namelen) > MAXPATHLEN) { 2239 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2240 pid, name, uid, temp, name); 2241 kfree(temp, M_TEMP); 2242 return NULL; 2243 } 2244 memcpy(temp+n, name, namelen); 2245 n += namelen; 2246 break; 2247 case 'P': /* process id */ 2248 l = ksprintf(buf, "%u", pid); 2249 if ((n + l) > MAXPATHLEN) { 2250 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2251 pid, name, uid, temp, name); 2252 kfree(temp, M_TEMP); 2253 return NULL; 2254 } 2255 memcpy(temp+n, buf, l); 2256 n += l; 2257 break; 2258 case 'U': /* user id */ 2259 l = ksprintf(buf, "%u", uid); 2260 if ((n + l) > MAXPATHLEN) { 2261 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2262 pid, name, uid, temp, name); 2263 kfree(temp, M_TEMP); 2264 return NULL; 2265 } 2266 memcpy(temp+n, buf, l); 2267 n += l; 2268 break; 2269 default: 2270 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2271 } 2272 break; 2273 default: 2274 temp[n++] = format[i]; 2275 } 2276 } 2277 temp[n] = '\0'; 2278 return temp; 2279 } 2280 2281 /* 2282 * Dump a process' core. The main routine does some 2283 * policy checking, and creates the name of the coredump; 2284 * then it passes on a vnode and a size limit to the process-specific 2285 * coredump routine if there is one; if there _is not_ one, it returns 2286 * ENOSYS; otherwise it returns the error from the process-specific routine. 2287 * 2288 * The parameter `lp' is the lwp which triggered the coredump. 2289 */ 2290 2291 static int 2292 coredump(struct lwp *lp, int sig) 2293 { 2294 struct proc *p = lp->lwp_proc; 2295 struct vnode *vp; 2296 struct ucred *cred = p->p_ucred; 2297 struct flock lf; 2298 struct nlookupdata nd; 2299 struct vattr vattr; 2300 int error, error1; 2301 char *name; /* name of corefile */ 2302 off_t limit; 2303 2304 STOPEVENT(p, S_CORE, 0); 2305 2306 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2307 return (EFAULT); 2308 2309 /* 2310 * Note that the bulk of limit checking is done after 2311 * the corefile is created. The exception is if the limit 2312 * for corefiles is 0, in which case we don't bother 2313 * creating the corefile at all. This layout means that 2314 * a corefile is truncated instead of not being created, 2315 * if it is larger than the limit. 2316 */ 2317 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2318 if (limit == 0) 2319 return EFBIG; 2320 2321 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2322 if (name == NULL) 2323 return (EINVAL); 2324 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2325 if (error == 0) 2326 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2327 kfree(name, M_TEMP); 2328 if (error) { 2329 nlookup_done(&nd); 2330 return (error); 2331 } 2332 vp = nd.nl_open_vp; 2333 nd.nl_open_vp = NULL; 2334 nlookup_done(&nd); 2335 2336 vn_unlock(vp); 2337 lf.l_whence = SEEK_SET; 2338 lf.l_start = 0; 2339 lf.l_len = 0; 2340 lf.l_type = F_WRLCK; 2341 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2342 if (error) 2343 goto out2; 2344 2345 /* Don't dump to non-regular files or files with links. */ 2346 if (vp->v_type != VREG || 2347 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2348 error = EFAULT; 2349 goto out1; 2350 } 2351 2352 /* Don't dump to files current user does not own */ 2353 if (vattr.va_uid != p->p_ucred->cr_uid) { 2354 error = EFAULT; 2355 goto out1; 2356 } 2357 2358 VATTR_NULL(&vattr); 2359 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2360 vattr.va_size = 0; 2361 VOP_SETATTR(vp, &vattr, cred); 2362 p->p_acflag |= ACORE; 2363 vn_unlock(vp); 2364 2365 error = p->p_sysent->sv_coredump ? 2366 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2367 2368 out1: 2369 lf.l_type = F_UNLCK; 2370 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2371 out2: 2372 error1 = vn_close(vp, FWRITE); 2373 if (error == 0) 2374 error = error1; 2375 return (error); 2376 } 2377 2378 /* 2379 * Nonexistent system call-- signal process (may want to handle it). 2380 * Flag error in case process won't see signal immediately (blocked or ignored). 2381 * 2382 * MPALMOSTSAFE 2383 */ 2384 /* ARGSUSED */ 2385 int 2386 sys_nosys(struct nosys_args *args) 2387 { 2388 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2389 return (EINVAL); 2390 } 2391 2392 /* 2393 * Send a SIGIO or SIGURG signal to a process or process group using 2394 * stored credentials rather than those of the current process. 2395 */ 2396 void 2397 pgsigio(struct sigio *sigio, int sig, int checkctty) 2398 { 2399 if (sigio == NULL) 2400 return; 2401 2402 if (sigio->sio_pgid > 0) { 2403 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2404 sigio->sio_proc)) 2405 ksignal(sigio->sio_proc, sig); 2406 } else if (sigio->sio_pgid < 0) { 2407 struct proc *p; 2408 struct pgrp *pg = sigio->sio_pgrp; 2409 2410 /* 2411 * Must interlock all signals against fork 2412 */ 2413 pgref(pg); 2414 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2415 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2416 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2417 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2418 ksignal(p, sig); 2419 } 2420 lockmgr(&pg->pg_lock, LK_RELEASE); 2421 pgrel(pg); 2422 } 2423 } 2424 2425 static int 2426 filt_sigattach(struct knote *kn) 2427 { 2428 struct proc *p = curproc; 2429 2430 kn->kn_ptr.p_proc = p; 2431 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2432 2433 /* XXX lock the proc here while adding to the list? */ 2434 knote_insert(&p->p_klist, kn); 2435 2436 return (0); 2437 } 2438 2439 static void 2440 filt_sigdetach(struct knote *kn) 2441 { 2442 struct proc *p = kn->kn_ptr.p_proc; 2443 2444 knote_remove(&p->p_klist, kn); 2445 } 2446 2447 /* 2448 * signal knotes are shared with proc knotes, so we apply a mask to 2449 * the hint in order to differentiate them from process hints. This 2450 * could be avoided by using a signal-specific knote list, but probably 2451 * isn't worth the trouble. 2452 */ 2453 static int 2454 filt_signal(struct knote *kn, long hint) 2455 { 2456 if (hint & NOTE_SIGNAL) { 2457 hint &= ~NOTE_SIGNAL; 2458 2459 if (kn->kn_id == hint) 2460 kn->kn_data++; 2461 } 2462 return (kn->kn_data != 0); 2463 } 2464