1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/sysproto.h> 48 #include <sys/signalvar.h> 49 #include <sys/resourcevar.h> 50 #include <sys/vnode.h> 51 #include <sys/event.h> 52 #include <sys/proc.h> 53 #include <sys/nlookup.h> 54 #include <sys/pioctl.h> 55 #include <sys/acct.h> 56 #include <sys/fcntl.h> 57 #include <sys/lock.h> 58 #include <sys/wait.h> 59 #include <sys/ktrace.h> 60 #include <sys/syslog.h> 61 #include <sys/stat.h> 62 #include <sys/sysent.h> 63 #include <sys/sysctl.h> 64 #include <sys/malloc.h> 65 #include <sys/interrupt.h> 66 #include <sys/unistd.h> 67 #include <sys/kern_syscall.h> 68 #include <sys/vkernel.h> 69 70 #include <sys/signal2.h> 71 #include <sys/thread2.h> 72 #include <sys/spinlock2.h> 73 74 #include <machine/cpu.h> 75 #include <machine/smp.h> 76 77 static int coredump(struct lwp *, int); 78 static char *expand_name(const char *, uid_t, pid_t); 79 static int dokillpg(int sig, int pgid, int all); 80 static int sig_ffs(sigset_t *set); 81 static int sigprop(int sig); 82 static void lwp_signotify(struct lwp *lp); 83 #ifdef SMP 84 static void lwp_signotify_remote(void *arg); 85 #endif 86 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 87 struct timespec *timeout); 88 89 static int filt_sigattach(struct knote *kn); 90 static void filt_sigdetach(struct knote *kn); 91 static int filt_signal(struct knote *kn, long hint); 92 93 struct filterops sig_filtops = 94 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 95 96 static int kern_logsigexit = 1; 97 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 98 &kern_logsigexit, 0, 99 "Log processes quitting on abnormal signals to syslog(3)"); 100 101 /* 102 * Can process p, with pcred pc, send the signal sig to process q? 103 */ 104 #define CANSIGNAL(q, sig) \ 105 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 106 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 107 108 /* 109 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 110 */ 111 #define CANSIGIO(ruid, uc, q) \ 112 ((uc)->cr_uid == 0 || \ 113 (ruid) == (q)->p_ucred->cr_ruid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 115 (ruid) == (q)->p_ucred->cr_uid || \ 116 (uc)->cr_uid == (q)->p_ucred->cr_uid) 117 118 int sugid_coredump; 119 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 120 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 121 122 static int do_coredump = 1; 123 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 124 &do_coredump, 0, "Enable/Disable coredumps"); 125 126 /* 127 * Signal properties and actions. 128 * The array below categorizes the signals and their default actions 129 * according to the following properties: 130 */ 131 #define SA_KILL 0x01 /* terminates process by default */ 132 #define SA_CORE 0x02 /* ditto and coredumps */ 133 #define SA_STOP 0x04 /* suspend process */ 134 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 135 #define SA_IGNORE 0x10 /* ignore by default */ 136 #define SA_CONT 0x20 /* continue if suspended */ 137 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 138 #define SA_CKPT 0x80 /* checkpoint process */ 139 140 141 static int sigproptbl[NSIG] = { 142 SA_KILL, /* SIGHUP */ 143 SA_KILL, /* SIGINT */ 144 SA_KILL|SA_CORE, /* SIGQUIT */ 145 SA_KILL|SA_CORE, /* SIGILL */ 146 SA_KILL|SA_CORE, /* SIGTRAP */ 147 SA_KILL|SA_CORE, /* SIGABRT */ 148 SA_KILL|SA_CORE, /* SIGEMT */ 149 SA_KILL|SA_CORE, /* SIGFPE */ 150 SA_KILL, /* SIGKILL */ 151 SA_KILL|SA_CORE, /* SIGBUS */ 152 SA_KILL|SA_CORE, /* SIGSEGV */ 153 SA_KILL|SA_CORE, /* SIGSYS */ 154 SA_KILL, /* SIGPIPE */ 155 SA_KILL, /* SIGALRM */ 156 SA_KILL, /* SIGTERM */ 157 SA_IGNORE, /* SIGURG */ 158 SA_STOP, /* SIGSTOP */ 159 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 160 SA_IGNORE|SA_CONT, /* SIGCONT */ 161 SA_IGNORE, /* SIGCHLD */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 163 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 164 SA_IGNORE, /* SIGIO */ 165 SA_KILL, /* SIGXCPU */ 166 SA_KILL, /* SIGXFSZ */ 167 SA_KILL, /* SIGVTALRM */ 168 SA_KILL, /* SIGPROF */ 169 SA_IGNORE, /* SIGWINCH */ 170 SA_IGNORE, /* SIGINFO */ 171 SA_KILL, /* SIGUSR1 */ 172 SA_KILL, /* SIGUSR2 */ 173 SA_IGNORE, /* SIGTHR */ 174 SA_CKPT, /* SIGCKPT */ 175 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 SA_IGNORE, 206 207 }; 208 209 static __inline int 210 sigprop(int sig) 211 { 212 213 if (sig > 0 && sig < NSIG) 214 return (sigproptbl[_SIG_IDX(sig)]); 215 return (0); 216 } 217 218 static __inline int 219 sig_ffs(sigset_t *set) 220 { 221 int i; 222 223 for (i = 0; i < _SIG_WORDS; i++) 224 if (set->__bits[i]) 225 return (ffs(set->__bits[i]) + (i * 32)); 226 return (0); 227 } 228 229 /* 230 * No requirements. 231 */ 232 int 233 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 234 { 235 struct thread *td = curthread; 236 struct proc *p = td->td_proc; 237 struct lwp *lp; 238 struct sigacts *ps = p->p_sigacts; 239 240 if (sig <= 0 || sig > _SIG_MAXSIG) 241 return (EINVAL); 242 243 lwkt_gettoken(&p->p_token); 244 245 if (oact) { 246 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 247 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 248 oact->sa_flags = 0; 249 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 250 oact->sa_flags |= SA_ONSTACK; 251 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 252 oact->sa_flags |= SA_RESTART; 253 if (SIGISMEMBER(ps->ps_sigreset, sig)) 254 oact->sa_flags |= SA_RESETHAND; 255 if (SIGISMEMBER(ps->ps_signodefer, sig)) 256 oact->sa_flags |= SA_NODEFER; 257 if (SIGISMEMBER(ps->ps_siginfo, sig)) 258 oact->sa_flags |= SA_SIGINFO; 259 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 260 oact->sa_flags |= SA_NOCLDSTOP; 261 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 262 oact->sa_flags |= SA_NOCLDWAIT; 263 } 264 if (act) { 265 /* 266 * Check for invalid requests. KILL and STOP cannot be 267 * caught. 268 */ 269 if (sig == SIGKILL || sig == SIGSTOP) { 270 if (act->sa_handler != SIG_DFL) { 271 lwkt_reltoken(&p->p_token); 272 return (EINVAL); 273 } 274 } 275 276 /* 277 * Change setting atomically. 278 */ 279 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 280 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 281 if (act->sa_flags & SA_SIGINFO) { 282 ps->ps_sigact[_SIG_IDX(sig)] = 283 (__sighandler_t *)act->sa_sigaction; 284 SIGADDSET(ps->ps_siginfo, sig); 285 } else { 286 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 287 SIGDELSET(ps->ps_siginfo, sig); 288 } 289 if (!(act->sa_flags & SA_RESTART)) 290 SIGADDSET(ps->ps_sigintr, sig); 291 else 292 SIGDELSET(ps->ps_sigintr, sig); 293 if (act->sa_flags & SA_ONSTACK) 294 SIGADDSET(ps->ps_sigonstack, sig); 295 else 296 SIGDELSET(ps->ps_sigonstack, sig); 297 if (act->sa_flags & SA_RESETHAND) 298 SIGADDSET(ps->ps_sigreset, sig); 299 else 300 SIGDELSET(ps->ps_sigreset, sig); 301 if (act->sa_flags & SA_NODEFER) 302 SIGADDSET(ps->ps_signodefer, sig); 303 else 304 SIGDELSET(ps->ps_signodefer, sig); 305 if (sig == SIGCHLD) { 306 if (act->sa_flags & SA_NOCLDSTOP) 307 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 308 else 309 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 310 if (act->sa_flags & SA_NOCLDWAIT) { 311 /* 312 * Paranoia: since SA_NOCLDWAIT is implemented 313 * by reparenting the dying child to PID 1 (and 314 * trust it to reap the zombie), PID 1 itself 315 * is forbidden to set SA_NOCLDWAIT. 316 */ 317 if (p->p_pid == 1) 318 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 319 else 320 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 321 } else { 322 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 323 } 324 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 325 ps->ps_flag |= PS_CLDSIGIGN; 326 else 327 ps->ps_flag &= ~PS_CLDSIGIGN; 328 } 329 /* 330 * Set bit in p_sigignore for signals that are set to SIG_IGN, 331 * and for signals set to SIG_DFL where the default is to 332 * ignore. However, don't put SIGCONT in p_sigignore, as we 333 * have to restart the process. 334 * 335 * Also remove the signal from the process and lwp signal 336 * list. 337 */ 338 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 339 (sigprop(sig) & SA_IGNORE && 340 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 341 SIGDELSET(p->p_siglist, sig); 342 FOREACH_LWP_IN_PROC(lp, p) { 343 spin_lock(&lp->lwp_spin); 344 SIGDELSET(lp->lwp_siglist, sig); 345 spin_unlock(&lp->lwp_spin); 346 } 347 if (sig != SIGCONT) { 348 /* easier in ksignal */ 349 SIGADDSET(p->p_sigignore, sig); 350 } 351 SIGDELSET(p->p_sigcatch, sig); 352 } else { 353 SIGDELSET(p->p_sigignore, sig); 354 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 355 SIGDELSET(p->p_sigcatch, sig); 356 else 357 SIGADDSET(p->p_sigcatch, sig); 358 } 359 } 360 lwkt_reltoken(&p->p_token); 361 return (0); 362 } 363 364 int 365 sys_sigaction(struct sigaction_args *uap) 366 { 367 struct sigaction act, oact; 368 struct sigaction *actp, *oactp; 369 int error; 370 371 actp = (uap->act != NULL) ? &act : NULL; 372 oactp = (uap->oact != NULL) ? &oact : NULL; 373 if (actp) { 374 error = copyin(uap->act, actp, sizeof(act)); 375 if (error) 376 return (error); 377 } 378 error = kern_sigaction(uap->sig, actp, oactp); 379 if (oactp && !error) { 380 error = copyout(oactp, uap->oact, sizeof(oact)); 381 } 382 return (error); 383 } 384 385 /* 386 * Initialize signal state for process 0; 387 * set to ignore signals that are ignored by default. 388 */ 389 void 390 siginit(struct proc *p) 391 { 392 int i; 393 394 for (i = 1; i <= NSIG; i++) 395 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 396 SIGADDSET(p->p_sigignore, i); 397 } 398 399 /* 400 * Reset signals for an exec of the specified process. 401 */ 402 void 403 execsigs(struct proc *p) 404 { 405 struct sigacts *ps = p->p_sigacts; 406 struct lwp *lp; 407 int sig; 408 409 lp = ONLY_LWP_IN_PROC(p); 410 411 /* 412 * Reset caught signals. Held signals remain held 413 * through p_sigmask (unless they were caught, 414 * and are now ignored by default). 415 */ 416 while (SIGNOTEMPTY(p->p_sigcatch)) { 417 sig = sig_ffs(&p->p_sigcatch); 418 SIGDELSET(p->p_sigcatch, sig); 419 if (sigprop(sig) & SA_IGNORE) { 420 if (sig != SIGCONT) 421 SIGADDSET(p->p_sigignore, sig); 422 SIGDELSET(p->p_siglist, sig); 423 /* don't need spinlock */ 424 SIGDELSET(lp->lwp_siglist, sig); 425 } 426 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 427 } 428 429 /* 430 * Reset stack state to the user stack. 431 * Clear set of signals caught on the signal stack. 432 */ 433 lp->lwp_sigstk.ss_flags = SS_DISABLE; 434 lp->lwp_sigstk.ss_size = 0; 435 lp->lwp_sigstk.ss_sp = 0; 436 lp->lwp_flags &= ~LWP_ALTSTACK; 437 /* 438 * Reset no zombies if child dies flag as Solaris does. 439 */ 440 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 441 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 442 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 443 } 444 445 /* 446 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 447 * 448 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 449 * p == curproc. 450 */ 451 int 452 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 453 { 454 struct thread *td = curthread; 455 struct lwp *lp = td->td_lwp; 456 struct proc *p = td->td_proc; 457 int error; 458 459 lwkt_gettoken(&p->p_token); 460 461 if (oset != NULL) 462 *oset = lp->lwp_sigmask; 463 464 error = 0; 465 if (set != NULL) { 466 switch (how) { 467 case SIG_BLOCK: 468 SIG_CANTMASK(*set); 469 SIGSETOR(lp->lwp_sigmask, *set); 470 break; 471 case SIG_UNBLOCK: 472 SIGSETNAND(lp->lwp_sigmask, *set); 473 break; 474 case SIG_SETMASK: 475 SIG_CANTMASK(*set); 476 lp->lwp_sigmask = *set; 477 break; 478 default: 479 error = EINVAL; 480 break; 481 } 482 } 483 484 lwkt_reltoken(&p->p_token); 485 486 return (error); 487 } 488 489 /* 490 * sigprocmask() 491 * 492 * MPSAFE 493 */ 494 int 495 sys_sigprocmask(struct sigprocmask_args *uap) 496 { 497 sigset_t set, oset; 498 sigset_t *setp, *osetp; 499 int error; 500 501 setp = (uap->set != NULL) ? &set : NULL; 502 osetp = (uap->oset != NULL) ? &oset : NULL; 503 if (setp) { 504 error = copyin(uap->set, setp, sizeof(set)); 505 if (error) 506 return (error); 507 } 508 error = kern_sigprocmask(uap->how, setp, osetp); 509 if (osetp && !error) { 510 error = copyout(osetp, uap->oset, sizeof(oset)); 511 } 512 return (error); 513 } 514 515 /* 516 * MPSAFE 517 */ 518 int 519 kern_sigpending(struct __sigset *set) 520 { 521 struct lwp *lp = curthread->td_lwp; 522 523 *set = lwp_sigpend(lp); 524 525 return (0); 526 } 527 528 /* 529 * MPSAFE 530 */ 531 int 532 sys_sigpending(struct sigpending_args *uap) 533 { 534 sigset_t set; 535 int error; 536 537 error = kern_sigpending(&set); 538 539 if (error == 0) 540 error = copyout(&set, uap->set, sizeof(set)); 541 return (error); 542 } 543 544 /* 545 * Suspend process until signal, providing mask to be set 546 * in the meantime. 547 * 548 * MPSAFE 549 */ 550 int 551 kern_sigsuspend(struct __sigset *set) 552 { 553 struct thread *td = curthread; 554 struct lwp *lp = td->td_lwp; 555 struct proc *p = td->td_proc; 556 struct sigacts *ps = p->p_sigacts; 557 558 /* 559 * When returning from sigsuspend, we want 560 * the old mask to be restored after the 561 * signal handler has finished. Thus, we 562 * save it here and mark the sigacts structure 563 * to indicate this. 564 */ 565 lp->lwp_oldsigmask = lp->lwp_sigmask; 566 lp->lwp_flags |= LWP_OLDMASK; 567 568 SIG_CANTMASK(*set); 569 lp->lwp_sigmask = *set; 570 while (tsleep(ps, PCATCH, "pause", 0) == 0) 571 /* void */; 572 /* always return EINTR rather than ERESTART... */ 573 return (EINTR); 574 } 575 576 /* 577 * Note nonstandard calling convention: libc stub passes mask, not 578 * pointer, to save a copyin. 579 * 580 * MPSAFE 581 */ 582 int 583 sys_sigsuspend(struct sigsuspend_args *uap) 584 { 585 sigset_t mask; 586 int error; 587 588 error = copyin(uap->sigmask, &mask, sizeof(mask)); 589 if (error) 590 return (error); 591 592 error = kern_sigsuspend(&mask); 593 594 return (error); 595 } 596 597 /* 598 * MPSAFE 599 */ 600 int 601 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 602 { 603 struct thread *td = curthread; 604 struct lwp *lp = td->td_lwp; 605 struct proc *p = td->td_proc; 606 607 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 608 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 609 610 if (oss) 611 *oss = lp->lwp_sigstk; 612 613 if (ss) { 614 if (ss->ss_flags & SS_DISABLE) { 615 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 616 return (EINVAL); 617 lp->lwp_flags &= ~LWP_ALTSTACK; 618 lp->lwp_sigstk.ss_flags = ss->ss_flags; 619 } else { 620 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 621 return (ENOMEM); 622 lp->lwp_flags |= LWP_ALTSTACK; 623 lp->lwp_sigstk = *ss; 624 } 625 } 626 627 return (0); 628 } 629 630 /* 631 * MPSAFE 632 */ 633 int 634 sys_sigaltstack(struct sigaltstack_args *uap) 635 { 636 stack_t ss, oss; 637 int error; 638 639 if (uap->ss) { 640 error = copyin(uap->ss, &ss, sizeof(ss)); 641 if (error) 642 return (error); 643 } 644 645 error = kern_sigaltstack(uap->ss ? &ss : NULL, 646 uap->oss ? &oss : NULL); 647 648 if (error == 0 && uap->oss) 649 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 650 return (error); 651 } 652 653 /* 654 * Common code for kill process group/broadcast kill. 655 * cp is calling process. 656 */ 657 struct killpg_info { 658 int nfound; 659 int sig; 660 }; 661 662 static int killpg_all_callback(struct proc *p, void *data); 663 664 static int 665 dokillpg(int sig, int pgid, int all) 666 { 667 struct killpg_info info; 668 struct proc *cp = curproc; 669 struct proc *p; 670 struct pgrp *pgrp; 671 672 info.nfound = 0; 673 info.sig = sig; 674 675 if (all) { 676 /* 677 * broadcast 678 */ 679 allproc_scan(killpg_all_callback, &info); 680 } else { 681 if (pgid == 0) { 682 /* 683 * zero pgid means send to my process group. 684 */ 685 pgrp = cp->p_pgrp; 686 pgref(pgrp); 687 } else { 688 pgrp = pgfind(pgid); 689 if (pgrp == NULL) 690 return (ESRCH); 691 } 692 693 /* 694 * Must interlock all signals against fork 695 */ 696 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 697 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 698 if (p->p_pid <= 1 || 699 p->p_stat == SZOMB || 700 (p->p_flags & P_SYSTEM) || 701 !CANSIGNAL(p, sig)) { 702 continue; 703 } 704 ++info.nfound; 705 if (sig) 706 ksignal(p, sig); 707 } 708 lockmgr(&pgrp->pg_lock, LK_RELEASE); 709 pgrel(pgrp); 710 } 711 return (info.nfound ? 0 : ESRCH); 712 } 713 714 static int 715 killpg_all_callback(struct proc *p, void *data) 716 { 717 struct killpg_info *info = data; 718 719 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 720 p == curproc || !CANSIGNAL(p, info->sig)) { 721 return (0); 722 } 723 ++info->nfound; 724 if (info->sig) 725 ksignal(p, info->sig); 726 return(0); 727 } 728 729 /* 730 * Send a general signal to a process or LWPs within that process. 731 * 732 * Note that new signals cannot be sent if a process is exiting or already 733 * a zombie, but we return success anyway as userland is likely to not handle 734 * the race properly. 735 * 736 * No requirements. 737 */ 738 int 739 kern_kill(int sig, pid_t pid, lwpid_t tid) 740 { 741 int t; 742 743 if ((u_int)sig > _SIG_MAXSIG) 744 return (EINVAL); 745 746 lwkt_gettoken(&proc_token); 747 748 if (pid > 0) { 749 struct proc *p; 750 struct lwp *lp = NULL; 751 752 /* 753 * Send a signal to a single process. If the kill() is 754 * racing an exiting process which has not yet been reaped 755 * act as though the signal was delivered successfully but 756 * don't actually try to deliver the signal. 757 */ 758 if ((p = pfind(pid)) == NULL) { 759 if ((p = zpfind(pid)) == NULL) { 760 lwkt_reltoken(&proc_token); 761 return (ESRCH); 762 } 763 lwkt_reltoken(&proc_token); 764 PRELE(p); 765 return (0); 766 } 767 lwkt_gettoken(&p->p_token); 768 if (!CANSIGNAL(p, sig)) { 769 lwkt_reltoken(&p->p_token); 770 PRELE(p); 771 lwkt_reltoken(&proc_token); 772 return (EPERM); 773 } 774 775 /* 776 * NOP if the process is exiting. Note that lwpsignal() is 777 * called directly with P_WEXIT set to kill individual LWPs 778 * during exit, which is allowed. 779 */ 780 if (p->p_flags & P_WEXIT) { 781 lwkt_reltoken(&p->p_token); 782 PRELE(p); 783 lwkt_reltoken(&proc_token); 784 return (0); 785 } 786 if (tid != -1) { 787 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 788 if (lp == NULL) { 789 lwkt_reltoken(&p->p_token); 790 PRELE(p); 791 lwkt_reltoken(&proc_token); 792 return (ESRCH); 793 } 794 } 795 if (sig) 796 lwpsignal(p, lp, sig); 797 lwkt_reltoken(&p->p_token); 798 PRELE(p); 799 lwkt_reltoken(&proc_token); 800 return (0); 801 } 802 803 /* 804 * If we come here, pid is a special broadcast pid. 805 * This doesn't mix with a tid. 806 */ 807 if (tid != -1) { 808 lwkt_reltoken(&proc_token); 809 return (EINVAL); 810 } 811 switch (pid) { 812 case -1: /* broadcast signal */ 813 t = (dokillpg(sig, 0, 1)); 814 break; 815 case 0: /* signal own process group */ 816 t = (dokillpg(sig, 0, 0)); 817 break; 818 default: /* negative explicit process group */ 819 t = (dokillpg(sig, -pid, 0)); 820 break; 821 } 822 lwkt_reltoken(&proc_token); 823 return t; 824 } 825 826 int 827 sys_kill(struct kill_args *uap) 828 { 829 int error; 830 831 error = kern_kill(uap->signum, uap->pid, -1); 832 return (error); 833 } 834 835 int 836 sys_lwp_kill(struct lwp_kill_args *uap) 837 { 838 int error; 839 pid_t pid = uap->pid; 840 841 /* 842 * A tid is mandatory for lwp_kill(), otherwise 843 * you could simply use kill(). 844 */ 845 if (uap->tid == -1) 846 return (EINVAL); 847 848 /* 849 * To save on a getpid() function call for intra-process 850 * signals, pid == -1 means current process. 851 */ 852 if (pid == -1) 853 pid = curproc->p_pid; 854 855 error = kern_kill(uap->signum, pid, uap->tid); 856 return (error); 857 } 858 859 /* 860 * Send a signal to a process group. 861 */ 862 void 863 gsignal(int pgid, int sig) 864 { 865 struct pgrp *pgrp; 866 867 if (pgid && (pgrp = pgfind(pgid))) 868 pgsignal(pgrp, sig, 0); 869 } 870 871 /* 872 * Send a signal to a process group. If checktty is 1, 873 * limit to members which have a controlling terminal. 874 * 875 * pg_lock interlocks against a fork that might be in progress, to 876 * ensure that the new child process picks up the signal. 877 */ 878 void 879 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 880 { 881 struct proc *p; 882 883 /* 884 * Must interlock all signals against fork 885 */ 886 if (pgrp) { 887 pgref(pgrp); 888 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 889 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 890 if (checkctty == 0 || p->p_flags & P_CONTROLT) 891 ksignal(p, sig); 892 } 893 lockmgr(&pgrp->pg_lock, LK_RELEASE); 894 pgrel(pgrp); 895 } 896 } 897 898 /* 899 * Send a signal caused by a trap to the current lwp. If it will be caught 900 * immediately, deliver it with correct code. Otherwise, post it normally. 901 * 902 * These signals may ONLY be delivered to the specified lwp and may never 903 * be delivered to the process generically. 904 */ 905 void 906 trapsignal(struct lwp *lp, int sig, u_long code) 907 { 908 struct proc *p = lp->lwp_proc; 909 struct sigacts *ps = p->p_sigacts; 910 911 /* 912 * If we are a virtual kernel running an emulated user process 913 * context, switch back to the virtual kernel context before 914 * trying to post the signal. 915 */ 916 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 917 struct trapframe *tf = lp->lwp_md.md_regs; 918 tf->tf_trapno = 0; 919 vkernel_trap(lp, tf); 920 } 921 922 923 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 924 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 925 lp->lwp_ru.ru_nsignals++; 926 #ifdef KTRACE 927 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 928 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 929 &lp->lwp_sigmask, code); 930 #endif 931 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 932 &lp->lwp_sigmask, code); 933 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 934 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 935 SIGADDSET(lp->lwp_sigmask, sig); 936 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 937 /* 938 * See kern_sigaction() for origin of this code. 939 */ 940 SIGDELSET(p->p_sigcatch, sig); 941 if (sig != SIGCONT && 942 sigprop(sig) & SA_IGNORE) 943 SIGADDSET(p->p_sigignore, sig); 944 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 945 } 946 } else { 947 lp->lwp_code = code; /* XXX for core dump/debugger */ 948 lp->lwp_sig = sig; /* XXX to verify code */ 949 lwpsignal(p, lp, sig); 950 } 951 } 952 953 /* 954 * Find a suitable lwp to deliver the signal to. Returns NULL if all 955 * lwps hold the signal blocked. 956 * 957 * Caller must hold p->p_token. 958 * 959 * Returns a lp or NULL. If non-NULL the lp is held and its token is 960 * acquired. 961 */ 962 static struct lwp * 963 find_lwp_for_signal(struct proc *p, int sig) 964 { 965 struct lwp *lp; 966 struct lwp *run, *sleep, *stop; 967 968 /* 969 * If the running/preempted thread belongs to the proc to which 970 * the signal is being delivered and this thread does not block 971 * the signal, then we can avoid a context switch by delivering 972 * the signal to this thread, because it will return to userland 973 * soon anyways. 974 */ 975 lp = lwkt_preempted_proc(); 976 if (lp != NULL && lp->lwp_proc == p) { 977 LWPHOLD(lp); 978 lwkt_gettoken(&lp->lwp_token); 979 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 980 /* return w/ token held */ 981 return (lp); 982 } 983 lwkt_reltoken(&lp->lwp_token); 984 LWPRELE(lp); 985 } 986 987 run = sleep = stop = NULL; 988 FOREACH_LWP_IN_PROC(lp, p) { 989 /* 990 * If the signal is being blocked by the lwp, then this 991 * lwp is not eligible for receiving the signal. 992 */ 993 LWPHOLD(lp); 994 lwkt_gettoken(&lp->lwp_token); 995 996 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 997 lwkt_reltoken(&lp->lwp_token); 998 LWPRELE(lp); 999 continue; 1000 } 1001 1002 switch (lp->lwp_stat) { 1003 case LSRUN: 1004 if (sleep) { 1005 lwkt_token_swap(); 1006 lwkt_reltoken(&sleep->lwp_token); 1007 LWPRELE(sleep); 1008 sleep = NULL; 1009 run = lp; 1010 } else if (stop) { 1011 lwkt_token_swap(); 1012 lwkt_reltoken(&stop->lwp_token); 1013 LWPRELE(stop); 1014 stop = NULL; 1015 run = lp; 1016 } else { 1017 run = lp; 1018 } 1019 break; 1020 case LSSLEEP: 1021 if (lp->lwp_flags & LWP_SINTR) { 1022 if (sleep) { 1023 lwkt_reltoken(&lp->lwp_token); 1024 LWPRELE(lp); 1025 } else if (stop) { 1026 lwkt_token_swap(); 1027 lwkt_reltoken(&stop->lwp_token); 1028 LWPRELE(stop); 1029 stop = NULL; 1030 sleep = lp; 1031 } else { 1032 sleep = lp; 1033 } 1034 } else { 1035 lwkt_reltoken(&lp->lwp_token); 1036 LWPRELE(lp); 1037 } 1038 break; 1039 case LSSTOP: 1040 if (sleep) { 1041 lwkt_reltoken(&lp->lwp_token); 1042 LWPRELE(lp); 1043 } else if (stop) { 1044 lwkt_reltoken(&lp->lwp_token); 1045 LWPRELE(lp); 1046 } else { 1047 stop = lp; 1048 } 1049 break; 1050 } 1051 if (run) 1052 break; 1053 } 1054 1055 if (run != NULL) 1056 return (run); 1057 else if (sleep != NULL) 1058 return (sleep); 1059 else 1060 return (stop); 1061 } 1062 1063 /* 1064 * Send the signal to the process. If the signal has an action, the action 1065 * is usually performed by the target process rather than the caller; we add 1066 * the signal to the set of pending signals for the process. 1067 * 1068 * Exceptions: 1069 * o When a stop signal is sent to a sleeping process that takes the 1070 * default action, the process is stopped without awakening it. 1071 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1072 * regardless of the signal action (eg, blocked or ignored). 1073 * 1074 * Other ignored signals are discarded immediately. 1075 * 1076 * If the caller wishes to call this function from a hard code section the 1077 * caller must already hold p->p_token (see kern_clock.c). 1078 * 1079 * No requirements. 1080 */ 1081 void 1082 ksignal(struct proc *p, int sig) 1083 { 1084 lwpsignal(p, NULL, sig); 1085 } 1086 1087 /* 1088 * The core for ksignal. lp may be NULL, then a suitable thread 1089 * will be chosen. If not, lp MUST be a member of p. 1090 * 1091 * If the caller wishes to call this function from a hard code section the 1092 * caller must already hold p->p_token. 1093 * 1094 * No requirements. 1095 */ 1096 void 1097 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1098 { 1099 struct proc *q; 1100 sig_t action; 1101 int prop; 1102 1103 if (sig > _SIG_MAXSIG || sig <= 0) { 1104 kprintf("lwpsignal: signal %d\n", sig); 1105 panic("lwpsignal signal number"); 1106 } 1107 1108 KKASSERT(lp == NULL || lp->lwp_proc == p); 1109 1110 /* 1111 * We don't want to race... well, all sorts of things. Get appropriate 1112 * tokens. 1113 * 1114 * Don't try to deliver a generic signal to an exiting process, 1115 * the signal structures could be in flux. We check the LWP later 1116 * on. 1117 */ 1118 PHOLD(p); 1119 lwkt_gettoken(&p->p_token); 1120 if (lp) { 1121 LWPHOLD(lp); 1122 lwkt_gettoken(&lp->lwp_token); 1123 } else if (p->p_flags & P_WEXIT) { 1124 goto out; 1125 } 1126 1127 prop = sigprop(sig); 1128 1129 /* 1130 * If proc is traced, always give parent a chance; 1131 * if signal event is tracked by procfs, give *that* 1132 * a chance, as well. 1133 */ 1134 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1135 action = SIG_DFL; 1136 } else { 1137 /* 1138 * Do not try to deliver signals to an exiting lwp. Note 1139 * that we must still deliver the signal if P_WEXIT is set 1140 * in the process flags. 1141 */ 1142 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT)) { 1143 if (lp) { 1144 lwkt_reltoken(&lp->lwp_token); 1145 LWPRELE(lp); 1146 } 1147 lwkt_reltoken(&p->p_token); 1148 PRELE(p); 1149 return; 1150 } 1151 1152 /* 1153 * If the signal is being ignored, then we forget about 1154 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1155 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1156 */ 1157 if (SIGISMEMBER(p->p_sigignore, sig)) { 1158 /* 1159 * Even if a signal is set SIG_IGN, it may still be 1160 * lurking in a kqueue. 1161 */ 1162 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1163 if (lp) { 1164 lwkt_reltoken(&lp->lwp_token); 1165 LWPRELE(lp); 1166 } 1167 lwkt_reltoken(&p->p_token); 1168 PRELE(p); 1169 return; 1170 } 1171 if (SIGISMEMBER(p->p_sigcatch, sig)) 1172 action = SIG_CATCH; 1173 else 1174 action = SIG_DFL; 1175 } 1176 1177 /* 1178 * If continuing, clear any pending STOP signals. 1179 */ 1180 if (prop & SA_CONT) 1181 SIG_STOPSIGMASK(p->p_siglist); 1182 1183 if (prop & SA_STOP) { 1184 /* 1185 * If sending a tty stop signal to a member of an orphaned 1186 * process group, discard the signal here if the action 1187 * is default; don't stop the process below if sleeping, 1188 * and don't clear any pending SIGCONT. 1189 */ 1190 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1191 action == SIG_DFL) { 1192 lwkt_reltoken(&p->p_token); 1193 PRELE(p); 1194 return; 1195 } 1196 SIG_CONTSIGMASK(p->p_siglist); 1197 p->p_flags &= ~P_CONTINUED; 1198 } 1199 1200 if (p->p_stat == SSTOP) { 1201 /* 1202 * Nobody can handle this signal, add it to the lwp or 1203 * process pending list 1204 */ 1205 if (lp) { 1206 spin_lock(&lp->lwp_spin); 1207 SIGADDSET(lp->lwp_siglist, sig); 1208 spin_unlock(&lp->lwp_spin); 1209 } else { 1210 SIGADDSET(p->p_siglist, sig); 1211 } 1212 1213 /* 1214 * If the process is stopped and is being traced, then no 1215 * further action is necessary. 1216 */ 1217 if (p->p_flags & P_TRACED) 1218 goto out; 1219 1220 /* 1221 * If the process is stopped and receives a KILL signal, 1222 * make the process runnable. 1223 */ 1224 if (sig == SIGKILL) { 1225 proc_unstop(p); 1226 goto active_process; 1227 } 1228 1229 /* 1230 * If the process is stopped and receives a CONT signal, 1231 * then try to make the process runnable again. 1232 */ 1233 if (prop & SA_CONT) { 1234 /* 1235 * If SIGCONT is default (or ignored), we continue the 1236 * process but don't leave the signal in p_siglist, as 1237 * it has no further action. If SIGCONT is held, we 1238 * continue the process and leave the signal in 1239 * p_siglist. If the process catches SIGCONT, let it 1240 * handle the signal itself. 1241 * 1242 * XXX what if the signal is being held blocked? 1243 * 1244 * Token required to interlock kern_wait(). 1245 * Reparenting can also cause a race so we have to 1246 * hold (q). 1247 */ 1248 q = p->p_pptr; 1249 PHOLD(q); 1250 lwkt_gettoken(&q->p_token); 1251 p->p_flags |= P_CONTINUED; 1252 wakeup(q); 1253 if (action == SIG_DFL) 1254 SIGDELSET(p->p_siglist, sig); 1255 proc_unstop(p); 1256 lwkt_reltoken(&q->p_token); 1257 PRELE(q); 1258 if (action == SIG_CATCH) 1259 goto active_process; 1260 goto out; 1261 } 1262 1263 /* 1264 * If the process is stopped and receives another STOP 1265 * signal, we do not need to stop it again. If we did 1266 * the shell could get confused. 1267 * 1268 * However, if the current/preempted lwp is part of the 1269 * process receiving the signal, we need to keep it, 1270 * so that this lwp can stop in issignal() later, as 1271 * we don't want to wait until it reaches userret! 1272 */ 1273 if (prop & SA_STOP) { 1274 if (lwkt_preempted_proc() == NULL || 1275 lwkt_preempted_proc()->lwp_proc != p) 1276 SIGDELSET(p->p_siglist, sig); 1277 } 1278 1279 /* 1280 * Otherwise the process is stopped and it received some 1281 * signal, which does not change its stopped state. When 1282 * the process is continued a wakeup(p) will be issued which 1283 * will wakeup any threads sleeping in tstop(). 1284 */ 1285 if (lp == NULL) { 1286 /* NOTE: returns lp w/ token held */ 1287 lp = find_lwp_for_signal(p, sig); 1288 } 1289 goto out; 1290 1291 /* NOTREACHED */ 1292 } 1293 /* else not stopped */ 1294 active_process: 1295 1296 /* 1297 * Never deliver a lwp-specific signal to a random lwp. 1298 */ 1299 if (lp == NULL) { 1300 /* NOTE: returns lp w/ token held */ 1301 lp = find_lwp_for_signal(p, sig); 1302 if (lp) { 1303 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1304 lwkt_reltoken(&lp->lwp_token); 1305 LWPRELE(lp); 1306 lp = NULL; 1307 } 1308 } 1309 } 1310 1311 /* 1312 * Deliver to the process generically if (1) the signal is being 1313 * sent to any thread or (2) we could not find a thread to deliver 1314 * it to. 1315 */ 1316 if (lp == NULL) { 1317 SIGADDSET(p->p_siglist, sig); 1318 goto out; 1319 } 1320 1321 /* 1322 * Deliver to a specific LWP whether it masks it or not. It will 1323 * not be dispatched if masked but we must still deliver it. 1324 */ 1325 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1326 (p->p_flags & P_TRACED) == 0) { 1327 p->p_nice = NZERO; 1328 } 1329 1330 /* 1331 * If the process receives a STOP signal which indeed needs to 1332 * stop the process, do so. If the process chose to catch the 1333 * signal, it will be treated like any other signal. 1334 */ 1335 if ((prop & SA_STOP) && action == SIG_DFL) { 1336 /* 1337 * If a child holding parent blocked, stopping 1338 * could cause deadlock. Take no action at this 1339 * time. 1340 */ 1341 if (p->p_flags & P_PPWAIT) { 1342 SIGADDSET(p->p_siglist, sig); 1343 goto out; 1344 } 1345 1346 /* 1347 * Do not actually try to manipulate the process, but simply 1348 * stop it. Lwps will stop as soon as they safely can. 1349 * 1350 * Ignore stop if the process is exiting. 1351 */ 1352 if ((p->p_flags & P_WEXIT) == 0) { 1353 p->p_xstat = sig; 1354 proc_stop(p); 1355 } 1356 goto out; 1357 } 1358 1359 /* 1360 * If it is a CONT signal with default action, just ignore it. 1361 */ 1362 if ((prop & SA_CONT) && action == SIG_DFL) 1363 goto out; 1364 1365 /* 1366 * Mark signal pending at this specific thread. 1367 */ 1368 spin_lock(&lp->lwp_spin); 1369 SIGADDSET(lp->lwp_siglist, sig); 1370 spin_unlock(&lp->lwp_spin); 1371 1372 lwp_signotify(lp); 1373 1374 out: 1375 if (lp) { 1376 lwkt_reltoken(&lp->lwp_token); 1377 LWPRELE(lp); 1378 } 1379 lwkt_reltoken(&p->p_token); 1380 PRELE(p); 1381 } 1382 1383 /* 1384 * Notify the LWP that a signal has arrived. The LWP does not have to be 1385 * sleeping on the current cpu. 1386 * 1387 * p->p_token and lp->lwp_token must be held on call. 1388 * 1389 * We can only safely schedule the thread on its current cpu and only if 1390 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1391 * the correct cpu we are properly interlocked, otherwise we could be 1392 * racing other thread transition states (or the lwp is on the user scheduler 1393 * runq but not scheduled) and must not do anything. 1394 * 1395 * Since we hold the lwp token we know the lwp cannot be ripped out from 1396 * under us so we can safely hold it to prevent it from being ripped out 1397 * from under us if we are forced to IPI another cpu to make the local 1398 * checks there. 1399 * 1400 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1401 * which we won't in an IPI so any fixups have to be done here, effectively 1402 * replicating part of what setrunnable() does. 1403 */ 1404 static void 1405 lwp_signotify(struct lwp *lp) 1406 { 1407 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1408 1409 crit_enter(); 1410 if (lp == lwkt_preempted_proc()) { 1411 /* 1412 * lwp is on the current cpu AND it is currently running 1413 * (we preempted it). 1414 */ 1415 signotify(); 1416 } else if (lp->lwp_flags & LWP_SINTR) { 1417 /* 1418 * lwp is sitting in tsleep() with PCATCH set 1419 */ 1420 #ifdef SMP 1421 if (lp->lwp_thread->td_gd == mycpu) { 1422 setrunnable(lp); 1423 } else { 1424 /* 1425 * We can only adjust lwp_stat while we hold the 1426 * lwp_token, and we won't in the IPI function. 1427 */ 1428 LWPHOLD(lp); 1429 if (lp->lwp_stat == LSSTOP) 1430 lp->lwp_stat = LSSLEEP; 1431 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1432 lwp_signotify_remote, lp); 1433 } 1434 #else 1435 setrunnable(lp); 1436 #endif 1437 } else if (lp->lwp_thread->td_flags & TDF_SINTR) { 1438 /* 1439 * lwp is sitting in lwkt_sleep() with PCATCH set. 1440 */ 1441 #ifdef SMP 1442 if (lp->lwp_thread->td_gd == mycpu) { 1443 setrunnable(lp); 1444 } else { 1445 /* 1446 * We can only adjust lwp_stat while we hold the 1447 * lwp_token, and we won't in the IPI function. 1448 */ 1449 LWPHOLD(lp); 1450 if (lp->lwp_stat == LSSTOP) 1451 lp->lwp_stat = LSSLEEP; 1452 lwkt_send_ipiq(lp->lwp_thread->td_gd, 1453 lwp_signotify_remote, lp); 1454 } 1455 #else 1456 setrunnable(lp); 1457 #endif 1458 } else { 1459 /* 1460 * Otherwise the lwp is either in some uninterruptable state 1461 * or it is on the userland scheduler's runqueue waiting to 1462 * be scheduled to a cpu. 1463 */ 1464 } 1465 crit_exit(); 1466 } 1467 1468 #ifdef SMP 1469 1470 /* 1471 * This function is called via an IPI so we cannot call setrunnable() here 1472 * (because while we hold the lp we don't own its token, and can't get it 1473 * from an IPI). 1474 * 1475 * We are interlocked by virtue of being on the same cpu as the target. If 1476 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1477 * the target thread. 1478 */ 1479 static void 1480 lwp_signotify_remote(void *arg) 1481 { 1482 struct lwp *lp = arg; 1483 thread_t td = lp->lwp_thread; 1484 1485 if (lp == lwkt_preempted_proc()) { 1486 signotify(); 1487 LWPRELE(lp); 1488 } else if (td->td_gd == mycpu) { 1489 if ((lp->lwp_flags & LWP_SINTR) || 1490 (td->td_flags & TDF_SINTR)) { 1491 lwkt_schedule(td); 1492 } 1493 LWPRELE(lp); 1494 } else { 1495 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1496 /* LWPHOLD() is forwarded to the target cpu */ 1497 } 1498 } 1499 1500 #endif 1501 1502 /* 1503 * Caller must hold p->p_token 1504 */ 1505 void 1506 proc_stop(struct proc *p) 1507 { 1508 struct proc *q; 1509 struct lwp *lp; 1510 1511 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1512 1513 /* If somebody raced us, be happy with it */ 1514 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1515 return; 1516 } 1517 p->p_stat = SSTOP; 1518 1519 FOREACH_LWP_IN_PROC(lp, p) { 1520 LWPHOLD(lp); 1521 lwkt_gettoken(&lp->lwp_token); 1522 1523 switch (lp->lwp_stat) { 1524 case LSSTOP: 1525 /* 1526 * Do nothing, we are already counted in 1527 * p_nstopped. 1528 */ 1529 break; 1530 1531 case LSSLEEP: 1532 /* 1533 * We're sleeping, but we will stop before 1534 * returning to userspace, so count us 1535 * as stopped as well. We set LWP_MP_WSTOP 1536 * to signal the lwp that it should not 1537 * increase p_nstopped when reaching tstop(). 1538 * 1539 * LWP_MP_WSTOP is protected by lp->lwp_token. 1540 */ 1541 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1542 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1543 ++p->p_nstopped; 1544 } 1545 break; 1546 1547 case LSRUN: 1548 /* 1549 * We might notify ourself, but that's not 1550 * a problem. 1551 */ 1552 lwp_signotify(lp); 1553 break; 1554 } 1555 lwkt_reltoken(&lp->lwp_token); 1556 LWPRELE(lp); 1557 } 1558 1559 if (p->p_nstopped == p->p_nthreads) { 1560 /* 1561 * Token required to interlock kern_wait(). Reparenting can 1562 * also cause a race so we have to hold (q). 1563 */ 1564 q = p->p_pptr; 1565 PHOLD(q); 1566 lwkt_gettoken(&q->p_token); 1567 p->p_flags &= ~P_WAITED; 1568 wakeup(q); 1569 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1570 ksignal(p->p_pptr, SIGCHLD); 1571 lwkt_reltoken(&q->p_token); 1572 PRELE(q); 1573 } 1574 } 1575 1576 /* 1577 * Caller must hold proc_token 1578 */ 1579 void 1580 proc_unstop(struct proc *p) 1581 { 1582 struct lwp *lp; 1583 1584 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1585 1586 if (p->p_stat != SSTOP) 1587 return; 1588 1589 p->p_stat = SACTIVE; 1590 1591 FOREACH_LWP_IN_PROC(lp, p) { 1592 LWPHOLD(lp); 1593 lwkt_gettoken(&lp->lwp_token); 1594 1595 switch (lp->lwp_stat) { 1596 case LSRUN: 1597 /* 1598 * Uh? Not stopped? Well, I guess that's okay. 1599 */ 1600 if (bootverbose) 1601 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1602 p->p_pid, lp->lwp_tid); 1603 break; 1604 1605 case LSSLEEP: 1606 /* 1607 * Still sleeping. Don't bother waking it up. 1608 * However, if this thread was counted as 1609 * stopped, undo this. 1610 * 1611 * Nevertheless we call setrunnable() so that it 1612 * will wake up in case a signal or timeout arrived 1613 * in the meantime. 1614 * 1615 * LWP_MP_WSTOP is protected by lp->lwp_token. 1616 */ 1617 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1618 atomic_clear_int(&lp->lwp_mpflags, 1619 LWP_MP_WSTOP); 1620 --p->p_nstopped; 1621 } else { 1622 if (bootverbose) 1623 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1624 p->p_pid, lp->lwp_tid); 1625 } 1626 /* FALLTHROUGH */ 1627 1628 case LSSTOP: 1629 /* 1630 * This handles any lwp's waiting in a tsleep with 1631 * SIGCATCH. 1632 */ 1633 lwp_signotify(lp); 1634 break; 1635 1636 } 1637 lwkt_reltoken(&lp->lwp_token); 1638 LWPRELE(lp); 1639 } 1640 1641 /* 1642 * This handles any lwp's waiting in tstop(). We have interlocked 1643 * the setting of p_stat by acquiring and releasing each lpw's 1644 * token. 1645 */ 1646 wakeup(p); 1647 } 1648 1649 /* 1650 * No requirements. 1651 */ 1652 static int 1653 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1654 { 1655 sigset_t savedmask, set; 1656 struct proc *p = curproc; 1657 struct lwp *lp = curthread->td_lwp; 1658 int error, sig, hz, timevalid = 0; 1659 struct timespec rts, ets, ts; 1660 struct timeval tv; 1661 1662 error = 0; 1663 sig = 0; 1664 ets.tv_sec = 0; /* silence compiler warning */ 1665 ets.tv_nsec = 0; /* silence compiler warning */ 1666 SIG_CANTMASK(waitset); 1667 savedmask = lp->lwp_sigmask; 1668 1669 if (timeout) { 1670 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1671 timeout->tv_nsec < 1000000000) { 1672 timevalid = 1; 1673 getnanouptime(&rts); 1674 ets = rts; 1675 timespecadd(&ets, timeout); 1676 } 1677 } 1678 1679 for (;;) { 1680 set = lwp_sigpend(lp); 1681 SIGSETAND(set, waitset); 1682 if ((sig = sig_ffs(&set)) != 0) { 1683 SIGFILLSET(lp->lwp_sigmask); 1684 SIGDELSET(lp->lwp_sigmask, sig); 1685 SIG_CANTMASK(lp->lwp_sigmask); 1686 sig = issignal(lp, 1); 1687 /* 1688 * It may be a STOP signal, in the case, issignal 1689 * returns 0, because we may stop there, and new 1690 * signal can come in, we should restart if we got 1691 * nothing. 1692 */ 1693 if (sig == 0) 1694 continue; 1695 else 1696 break; 1697 } 1698 1699 /* 1700 * Previous checking got nothing, and we retried but still 1701 * got nothing, we should return the error status. 1702 */ 1703 if (error) 1704 break; 1705 1706 /* 1707 * POSIX says this must be checked after looking for pending 1708 * signals. 1709 */ 1710 if (timeout) { 1711 if (timevalid == 0) { 1712 error = EINVAL; 1713 break; 1714 } 1715 getnanouptime(&rts); 1716 if (timespeccmp(&rts, &ets, >=)) { 1717 error = EAGAIN; 1718 break; 1719 } 1720 ts = ets; 1721 timespecsub(&ts, &rts); 1722 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1723 hz = tvtohz_high(&tv); 1724 } else { 1725 hz = 0; 1726 } 1727 1728 lp->lwp_sigmask = savedmask; 1729 SIGSETNAND(lp->lwp_sigmask, waitset); 1730 /* 1731 * We won't ever be woken up. Instead, our sleep will 1732 * be broken in lwpsignal(). 1733 */ 1734 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1735 if (timeout) { 1736 if (error == ERESTART) { 1737 /* can not restart a timeout wait. */ 1738 error = EINTR; 1739 } else if (error == EAGAIN) { 1740 /* will calculate timeout by ourself. */ 1741 error = 0; 1742 } 1743 } 1744 /* Retry ... */ 1745 } 1746 1747 lp->lwp_sigmask = savedmask; 1748 if (sig) { 1749 error = 0; 1750 bzero(info, sizeof(*info)); 1751 info->si_signo = sig; 1752 spin_lock(&lp->lwp_spin); 1753 lwp_delsig(lp, sig); /* take the signal! */ 1754 spin_unlock(&lp->lwp_spin); 1755 1756 if (sig == SIGKILL) { 1757 sigexit(lp, sig); 1758 /* NOT REACHED */ 1759 } 1760 } 1761 1762 return (error); 1763 } 1764 1765 /* 1766 * MPALMOSTSAFE 1767 */ 1768 int 1769 sys_sigtimedwait(struct sigtimedwait_args *uap) 1770 { 1771 struct timespec ts; 1772 struct timespec *timeout; 1773 sigset_t set; 1774 siginfo_t info; 1775 int error; 1776 1777 if (uap->timeout) { 1778 error = copyin(uap->timeout, &ts, sizeof(ts)); 1779 if (error) 1780 return (error); 1781 timeout = &ts; 1782 } else { 1783 timeout = NULL; 1784 } 1785 error = copyin(uap->set, &set, sizeof(set)); 1786 if (error) 1787 return (error); 1788 error = kern_sigtimedwait(set, &info, timeout); 1789 if (error) 1790 return (error); 1791 if (uap->info) 1792 error = copyout(&info, uap->info, sizeof(info)); 1793 /* Repost if we got an error. */ 1794 /* 1795 * XXX lwp 1796 * 1797 * This could transform a thread-specific signal to another 1798 * thread / process pending signal. 1799 */ 1800 if (error) { 1801 ksignal(curproc, info.si_signo); 1802 } else { 1803 uap->sysmsg_result = info.si_signo; 1804 } 1805 return (error); 1806 } 1807 1808 /* 1809 * MPALMOSTSAFE 1810 */ 1811 int 1812 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1813 { 1814 siginfo_t info; 1815 sigset_t set; 1816 int error; 1817 1818 error = copyin(uap->set, &set, sizeof(set)); 1819 if (error) 1820 return (error); 1821 error = kern_sigtimedwait(set, &info, NULL); 1822 if (error) 1823 return (error); 1824 if (uap->info) 1825 error = copyout(&info, uap->info, sizeof(info)); 1826 /* Repost if we got an error. */ 1827 /* 1828 * XXX lwp 1829 * 1830 * This could transform a thread-specific signal to another 1831 * thread / process pending signal. 1832 */ 1833 if (error) { 1834 ksignal(curproc, info.si_signo); 1835 } else { 1836 uap->sysmsg_result = info.si_signo; 1837 } 1838 return (error); 1839 } 1840 1841 /* 1842 * If the current process has received a signal that would interrupt a 1843 * system call, return EINTR or ERESTART as appropriate. 1844 */ 1845 int 1846 iscaught(struct lwp *lp) 1847 { 1848 struct proc *p = lp->lwp_proc; 1849 int sig; 1850 1851 if (p) { 1852 if ((sig = CURSIG(lp)) != 0) { 1853 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1854 return (EINTR); 1855 return (ERESTART); 1856 } 1857 } 1858 return(EWOULDBLOCK); 1859 } 1860 1861 /* 1862 * If the current process has received a signal (should be caught or cause 1863 * termination, should interrupt current syscall), return the signal number. 1864 * Stop signals with default action are processed immediately, then cleared; 1865 * they aren't returned. This is checked after each entry to the system for 1866 * a syscall or trap (though this can usually be done without calling issignal 1867 * by checking the pending signal masks in the CURSIG macro). 1868 * 1869 * This routine is called via CURSIG/__cursig. We will acquire and release 1870 * p->p_token but if the caller needs to interlock the test the caller must 1871 * also hold p->p_token. 1872 * 1873 * while (sig = CURSIG(curproc)) 1874 * postsig(sig); 1875 * 1876 * MPSAFE 1877 */ 1878 int 1879 issignal(struct lwp *lp, int maytrace) 1880 { 1881 struct proc *p = lp->lwp_proc; 1882 sigset_t mask; 1883 int sig, prop; 1884 1885 lwkt_gettoken(&p->p_token); 1886 1887 for (;;) { 1888 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1889 1890 /* 1891 * If this process is supposed to stop, stop this thread. 1892 */ 1893 if (p->p_stat == SSTOP) 1894 tstop(); 1895 1896 mask = lwp_sigpend(lp); 1897 SIGSETNAND(mask, lp->lwp_sigmask); 1898 if (p->p_flags & P_PPWAIT) 1899 SIG_STOPSIGMASK(mask); 1900 if (SIGISEMPTY(mask)) { /* no signal to send */ 1901 lwkt_reltoken(&p->p_token); 1902 return (0); 1903 } 1904 sig = sig_ffs(&mask); 1905 1906 STOPEVENT(p, S_SIG, sig); 1907 1908 /* 1909 * We should see pending but ignored signals 1910 * only if P_TRACED was on when they were posted. 1911 */ 1912 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1913 spin_lock(&lp->lwp_spin); 1914 lwp_delsig(lp, sig); 1915 spin_unlock(&lp->lwp_spin); 1916 continue; 1917 } 1918 if (maytrace && 1919 (p->p_flags & P_TRACED) && 1920 (p->p_flags & P_PPWAIT) == 0) { 1921 /* 1922 * If traced, always stop, and stay stopped until 1923 * released by the parent. 1924 * 1925 * NOTE: SSTOP may get cleared during the loop, 1926 * but we do not re-notify the parent if we have 1927 * to loop several times waiting for the parent 1928 * to let us continue. 1929 * 1930 * XXX not sure if this is still true 1931 */ 1932 p->p_xstat = sig; 1933 proc_stop(p); 1934 do { 1935 tstop(); 1936 } while (!trace_req(p) && (p->p_flags & P_TRACED)); 1937 1938 /* 1939 * If parent wants us to take the signal, 1940 * then it will leave it in p->p_xstat; 1941 * otherwise we just look for signals again. 1942 */ 1943 spin_lock(&lp->lwp_spin); 1944 lwp_delsig(lp, sig); /* clear old signal */ 1945 spin_unlock(&lp->lwp_spin); 1946 sig = p->p_xstat; 1947 if (sig == 0) 1948 continue; 1949 1950 /* 1951 * Put the new signal into p_siglist. If the 1952 * signal is being masked, look for other signals. 1953 * 1954 * XXX lwp might need a call to ksignal() 1955 */ 1956 SIGADDSET(p->p_siglist, sig); 1957 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1958 continue; 1959 1960 /* 1961 * If the traced bit got turned off, go back up 1962 * to the top to rescan signals. This ensures 1963 * that p_sig* and ps_sigact are consistent. 1964 */ 1965 if ((p->p_flags & P_TRACED) == 0) 1966 continue; 1967 } 1968 1969 prop = sigprop(sig); 1970 1971 /* 1972 * Decide whether the signal should be returned. 1973 * Return the signal's number, or fall through 1974 * to clear it from the pending mask. 1975 */ 1976 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1977 case (intptr_t)SIG_DFL: 1978 /* 1979 * Don't take default actions on system processes. 1980 */ 1981 if (p->p_pid <= 1) { 1982 #ifdef DIAGNOSTIC 1983 /* 1984 * Are you sure you want to ignore SIGSEGV 1985 * in init? XXX 1986 */ 1987 kprintf("Process (pid %lu) got signal %d\n", 1988 (u_long)p->p_pid, sig); 1989 #endif 1990 break; /* == ignore */ 1991 } 1992 1993 /* 1994 * Handle the in-kernel checkpoint action 1995 */ 1996 if (prop & SA_CKPT) { 1997 checkpoint_signal_handler(lp); 1998 break; 1999 } 2000 2001 /* 2002 * If there is a pending stop signal to process 2003 * with default action, stop here, 2004 * then clear the signal. However, 2005 * if process is member of an orphaned 2006 * process group, ignore tty stop signals. 2007 */ 2008 if (prop & SA_STOP) { 2009 if (p->p_flags & P_TRACED || 2010 (p->p_pgrp->pg_jobc == 0 && 2011 prop & SA_TTYSTOP)) 2012 break; /* == ignore */ 2013 if ((p->p_flags & P_WEXIT) == 0) { 2014 p->p_xstat = sig; 2015 proc_stop(p); 2016 tstop(); 2017 } 2018 break; 2019 } else if (prop & SA_IGNORE) { 2020 /* 2021 * Except for SIGCONT, shouldn't get here. 2022 * Default action is to ignore; drop it. 2023 */ 2024 break; /* == ignore */ 2025 } else { 2026 lwkt_reltoken(&p->p_token); 2027 return (sig); 2028 } 2029 2030 /*NOTREACHED*/ 2031 2032 case (intptr_t)SIG_IGN: 2033 /* 2034 * Masking above should prevent us ever trying 2035 * to take action on an ignored signal other 2036 * than SIGCONT, unless process is traced. 2037 */ 2038 if ((prop & SA_CONT) == 0 && 2039 (p->p_flags & P_TRACED) == 0) 2040 kprintf("issignal\n"); 2041 break; /* == ignore */ 2042 2043 default: 2044 /* 2045 * This signal has an action, let 2046 * postsig() process it. 2047 */ 2048 lwkt_reltoken(&p->p_token); 2049 return (sig); 2050 } 2051 spin_lock(&lp->lwp_spin); 2052 lwp_delsig(lp, sig); /* take the signal! */ 2053 spin_unlock(&lp->lwp_spin); 2054 } 2055 /* NOTREACHED */ 2056 } 2057 2058 /* 2059 * Take the action for the specified signal 2060 * from the current set of pending signals. 2061 * 2062 * Caller must hold p->p_token 2063 */ 2064 void 2065 postsig(int sig) 2066 { 2067 struct lwp *lp = curthread->td_lwp; 2068 struct proc *p = lp->lwp_proc; 2069 struct sigacts *ps = p->p_sigacts; 2070 sig_t action; 2071 sigset_t returnmask; 2072 int code; 2073 2074 KASSERT(sig != 0, ("postsig")); 2075 2076 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2077 2078 /* 2079 * If we are a virtual kernel running an emulated user process 2080 * context, switch back to the virtual kernel context before 2081 * trying to post the signal. 2082 */ 2083 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2084 struct trapframe *tf = lp->lwp_md.md_regs; 2085 tf->tf_trapno = 0; 2086 vkernel_trap(lp, tf); 2087 } 2088 2089 spin_lock(&lp->lwp_spin); 2090 lwp_delsig(lp, sig); 2091 spin_unlock(&lp->lwp_spin); 2092 action = ps->ps_sigact[_SIG_IDX(sig)]; 2093 #ifdef KTRACE 2094 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2095 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2096 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2097 #endif 2098 STOPEVENT(p, S_SIG, sig); 2099 2100 if (action == SIG_DFL) { 2101 /* 2102 * Default action, where the default is to kill 2103 * the process. (Other cases were ignored above.) 2104 */ 2105 sigexit(lp, sig); 2106 /* NOTREACHED */ 2107 } else { 2108 /* 2109 * If we get here, the signal must be caught. 2110 */ 2111 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2112 ("postsig action")); 2113 2114 /* 2115 * Reset the signal handler if asked to 2116 */ 2117 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2118 /* 2119 * See kern_sigaction() for origin of this code. 2120 */ 2121 SIGDELSET(p->p_sigcatch, sig); 2122 if (sig != SIGCONT && 2123 sigprop(sig) & SA_IGNORE) 2124 SIGADDSET(p->p_sigignore, sig); 2125 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2126 } 2127 2128 /* 2129 * Set the signal mask and calculate the mask to restore 2130 * when the signal function returns. 2131 * 2132 * Special case: user has done a sigsuspend. Here the 2133 * current mask is not of interest, but rather the 2134 * mask from before the sigsuspend is what we want 2135 * restored after the signal processing is completed. 2136 */ 2137 if (lp->lwp_flags & LWP_OLDMASK) { 2138 returnmask = lp->lwp_oldsigmask; 2139 lp->lwp_flags &= ~LWP_OLDMASK; 2140 } else { 2141 returnmask = lp->lwp_sigmask; 2142 } 2143 2144 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2145 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2146 SIGADDSET(lp->lwp_sigmask, sig); 2147 2148 lp->lwp_ru.ru_nsignals++; 2149 if (lp->lwp_sig != sig) { 2150 code = 0; 2151 } else { 2152 code = lp->lwp_code; 2153 lp->lwp_code = 0; 2154 lp->lwp_sig = 0; 2155 } 2156 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2157 } 2158 } 2159 2160 /* 2161 * Kill the current process for stated reason. 2162 */ 2163 void 2164 killproc(struct proc *p, char *why) 2165 { 2166 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2167 p->p_pid, p->p_comm, 2168 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2169 ksignal(p, SIGKILL); 2170 } 2171 2172 /* 2173 * Force the current process to exit with the specified signal, dumping core 2174 * if appropriate. We bypass the normal tests for masked and caught signals, 2175 * allowing unrecoverable failures to terminate the process without changing 2176 * signal state. Mark the accounting record with the signal termination. 2177 * If dumping core, save the signal number for the debugger. Calls exit and 2178 * does not return. 2179 * 2180 * This routine does not return. 2181 */ 2182 void 2183 sigexit(struct lwp *lp, int sig) 2184 { 2185 struct proc *p = lp->lwp_proc; 2186 2187 lwkt_gettoken(&p->p_token); 2188 p->p_acflag |= AXSIG; 2189 if (sigprop(sig) & SA_CORE) { 2190 lp->lwp_sig = sig; 2191 /* 2192 * Log signals which would cause core dumps 2193 * (Log as LOG_INFO to appease those who don't want 2194 * these messages.) 2195 * XXX : Todo, as well as euid, write out ruid too 2196 */ 2197 if (coredump(lp, sig) == 0) 2198 sig |= WCOREFLAG; 2199 if (kern_logsigexit) 2200 log(LOG_INFO, 2201 "pid %d (%s), uid %d: exited on signal %d%s\n", 2202 p->p_pid, p->p_comm, 2203 p->p_ucred ? p->p_ucred->cr_uid : -1, 2204 sig &~ WCOREFLAG, 2205 sig & WCOREFLAG ? " (core dumped)" : ""); 2206 } 2207 lwkt_reltoken(&p->p_token); 2208 exit1(W_EXITCODE(0, sig)); 2209 /* NOTREACHED */ 2210 } 2211 2212 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2213 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2214 sizeof(corefilename), "process corefile name format string"); 2215 2216 /* 2217 * expand_name(name, uid, pid) 2218 * Expand the name described in corefilename, using name, uid, and pid. 2219 * corefilename is a kprintf-like string, with three format specifiers: 2220 * %N name of process ("name") 2221 * %P process id (pid) 2222 * %U user id (uid) 2223 * For example, "%N.core" is the default; they can be disabled completely 2224 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2225 * This is controlled by the sysctl variable kern.corefile (see above). 2226 */ 2227 2228 static char * 2229 expand_name(const char *name, uid_t uid, pid_t pid) 2230 { 2231 char *temp; 2232 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2233 int i, n; 2234 char *format = corefilename; 2235 size_t namelen; 2236 2237 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2238 if (temp == NULL) 2239 return NULL; 2240 namelen = strlen(name); 2241 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2242 int l; 2243 switch (format[i]) { 2244 case '%': /* Format character */ 2245 i++; 2246 switch (format[i]) { 2247 case '%': 2248 temp[n++] = '%'; 2249 break; 2250 case 'N': /* process name */ 2251 if ((n + namelen) > 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, name, namelen); 2258 n += namelen; 2259 break; 2260 case 'P': /* process id */ 2261 l = ksprintf(buf, "%u", pid); 2262 if ((n + l) > MAXPATHLEN) { 2263 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2264 pid, name, uid, temp, name); 2265 kfree(temp, M_TEMP); 2266 return NULL; 2267 } 2268 memcpy(temp+n, buf, l); 2269 n += l; 2270 break; 2271 case 'U': /* user id */ 2272 l = ksprintf(buf, "%u", uid); 2273 if ((n + l) > MAXPATHLEN) { 2274 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2275 pid, name, uid, temp, name); 2276 kfree(temp, M_TEMP); 2277 return NULL; 2278 } 2279 memcpy(temp+n, buf, l); 2280 n += l; 2281 break; 2282 default: 2283 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2284 } 2285 break; 2286 default: 2287 temp[n++] = format[i]; 2288 } 2289 } 2290 temp[n] = '\0'; 2291 return temp; 2292 } 2293 2294 /* 2295 * Dump a process' core. The main routine does some 2296 * policy checking, and creates the name of the coredump; 2297 * then it passes on a vnode and a size limit to the process-specific 2298 * coredump routine if there is one; if there _is not_ one, it returns 2299 * ENOSYS; otherwise it returns the error from the process-specific routine. 2300 * 2301 * The parameter `lp' is the lwp which triggered the coredump. 2302 */ 2303 2304 static int 2305 coredump(struct lwp *lp, int sig) 2306 { 2307 struct proc *p = lp->lwp_proc; 2308 struct vnode *vp; 2309 struct ucred *cred = p->p_ucred; 2310 struct flock lf; 2311 struct nlookupdata nd; 2312 struct vattr vattr; 2313 int error, error1; 2314 char *name; /* name of corefile */ 2315 off_t limit; 2316 2317 STOPEVENT(p, S_CORE, 0); 2318 2319 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2320 return (EFAULT); 2321 2322 /* 2323 * Note that the bulk of limit checking is done after 2324 * the corefile is created. The exception is if the limit 2325 * for corefiles is 0, in which case we don't bother 2326 * creating the corefile at all. This layout means that 2327 * a corefile is truncated instead of not being created, 2328 * if it is larger than the limit. 2329 */ 2330 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2331 if (limit == 0) 2332 return EFBIG; 2333 2334 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2335 if (name == NULL) 2336 return (EINVAL); 2337 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2338 if (error == 0) 2339 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2340 kfree(name, M_TEMP); 2341 if (error) { 2342 nlookup_done(&nd); 2343 return (error); 2344 } 2345 vp = nd.nl_open_vp; 2346 nd.nl_open_vp = NULL; 2347 nlookup_done(&nd); 2348 2349 vn_unlock(vp); 2350 lf.l_whence = SEEK_SET; 2351 lf.l_start = 0; 2352 lf.l_len = 0; 2353 lf.l_type = F_WRLCK; 2354 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2355 if (error) 2356 goto out2; 2357 2358 /* Don't dump to non-regular files or files with links. */ 2359 if (vp->v_type != VREG || 2360 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2361 error = EFAULT; 2362 goto out1; 2363 } 2364 2365 /* Don't dump to files current user does not own */ 2366 if (vattr.va_uid != p->p_ucred->cr_uid) { 2367 error = EFAULT; 2368 goto out1; 2369 } 2370 2371 VATTR_NULL(&vattr); 2372 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2373 vattr.va_size = 0; 2374 VOP_SETATTR(vp, &vattr, cred); 2375 p->p_acflag |= ACORE; 2376 vn_unlock(vp); 2377 2378 error = p->p_sysent->sv_coredump ? 2379 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2380 2381 out1: 2382 lf.l_type = F_UNLCK; 2383 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2384 out2: 2385 error1 = vn_close(vp, FWRITE); 2386 if (error == 0) 2387 error = error1; 2388 return (error); 2389 } 2390 2391 /* 2392 * Nonexistent system call-- signal process (may want to handle it). 2393 * Flag error in case process won't see signal immediately (blocked or ignored). 2394 * 2395 * MPALMOSTSAFE 2396 */ 2397 /* ARGSUSED */ 2398 int 2399 sys_nosys(struct nosys_args *args) 2400 { 2401 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2402 return (EINVAL); 2403 } 2404 2405 /* 2406 * Send a SIGIO or SIGURG signal to a process or process group using 2407 * stored credentials rather than those of the current process. 2408 */ 2409 void 2410 pgsigio(struct sigio *sigio, int sig, int checkctty) 2411 { 2412 if (sigio == NULL) 2413 return; 2414 2415 if (sigio->sio_pgid > 0) { 2416 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2417 sigio->sio_proc)) 2418 ksignal(sigio->sio_proc, sig); 2419 } else if (sigio->sio_pgid < 0) { 2420 struct proc *p; 2421 struct pgrp *pg = sigio->sio_pgrp; 2422 2423 /* 2424 * Must interlock all signals against fork 2425 */ 2426 pgref(pg); 2427 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2428 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2429 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2430 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2431 ksignal(p, sig); 2432 } 2433 lockmgr(&pg->pg_lock, LK_RELEASE); 2434 pgrel(pg); 2435 } 2436 } 2437 2438 static int 2439 filt_sigattach(struct knote *kn) 2440 { 2441 struct proc *p = curproc; 2442 2443 kn->kn_ptr.p_proc = p; 2444 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2445 2446 /* XXX lock the proc here while adding to the list? */ 2447 knote_insert(&p->p_klist, kn); 2448 2449 return (0); 2450 } 2451 2452 static void 2453 filt_sigdetach(struct knote *kn) 2454 { 2455 struct proc *p = kn->kn_ptr.p_proc; 2456 2457 knote_remove(&p->p_klist, kn); 2458 } 2459 2460 /* 2461 * signal knotes are shared with proc knotes, so we apply a mask to 2462 * the hint in order to differentiate them from process hints. This 2463 * could be avoided by using a signal-specific knote list, but probably 2464 * isn't worth the trouble. 2465 */ 2466 static int 2467 filt_signal(struct knote *kn, long hint) 2468 { 2469 if (hint & NOTE_SIGNAL) { 2470 hint &= ~NOTE_SIGNAL; 2471 2472 if (kn->kn_id == hint) 2473 kn->kn_data++; 2474 } 2475 return (kn->kn_data != 0); 2476 } 2477