1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 35 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 36 */ 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/sysproto.h> 44 #include <sys/signalvar.h> 45 #include <sys/resourcevar.h> 46 #include <sys/vnode.h> 47 #include <sys/event.h> 48 #include <sys/proc.h> 49 #include <sys/nlookup.h> 50 #include <sys/pioctl.h> 51 #include <sys/acct.h> 52 #include <sys/fcntl.h> 53 #include <sys/lock.h> 54 #include <sys/wait.h> 55 #include <sys/ktrace.h> 56 #include <sys/syslog.h> 57 #include <sys/stat.h> 58 #include <sys/sysent.h> 59 #include <sys/sysctl.h> 60 #include <sys/malloc.h> 61 #include <sys/interrupt.h> 62 #include <sys/unistd.h> 63 #include <sys/kern_syscall.h> 64 #include <sys/vkernel.h> 65 66 #include <sys/signal2.h> 67 #include <sys/thread2.h> 68 #include <sys/spinlock2.h> 69 70 #include <machine/cpu.h> 71 #include <machine/smp.h> 72 73 static int coredump(struct lwp *, int); 74 static char *expand_name(const char *, uid_t, pid_t); 75 static int dokillpg(int sig, int pgid, int all); 76 static int sig_ffs(sigset_t *set); 77 static int sigprop(int sig); 78 static void lwp_signotify(struct lwp *lp); 79 static void lwp_signotify_remote(void *arg); 80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 81 struct timespec *timeout); 82 static void proc_stopwait(struct proc *p); 83 84 static int filt_sigattach(struct knote *kn); 85 static void filt_sigdetach(struct knote *kn); 86 static int filt_signal(struct knote *kn, long hint); 87 88 struct filterops sig_filtops = 89 { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, filt_signal }; 90 91 static int kern_logsigexit = 1; 92 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 93 &kern_logsigexit, 0, 94 "Log processes quitting on abnormal signals to syslog(3)"); 95 96 /* 97 * Can process p, with pcred pc, send the signal sig to process q? 98 */ 99 #define CANSIGNAL(q, sig) \ 100 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 101 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 102 103 /* 104 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 105 */ 106 #define CANSIGIO(ruid, uc, q) \ 107 ((uc)->cr_uid == 0 || \ 108 (ruid) == (q)->p_ucred->cr_ruid || \ 109 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 110 (ruid) == (q)->p_ucred->cr_uid || \ 111 (uc)->cr_uid == (q)->p_ucred->cr_uid) 112 113 int sugid_coredump; 114 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 115 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 116 117 static int do_coredump = 1; 118 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 119 &do_coredump, 0, "Enable/Disable coredumps"); 120 121 /* 122 * Signal properties and actions. 123 * The array below categorizes the signals and their default actions 124 * according to the following properties: 125 */ 126 #define SA_KILL 0x01 /* terminates process by default */ 127 #define SA_CORE 0x02 /* ditto and coredumps */ 128 #define SA_STOP 0x04 /* suspend process */ 129 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 130 #define SA_IGNORE 0x10 /* ignore by default */ 131 #define SA_CONT 0x20 /* continue if suspended */ 132 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 133 #define SA_CKPT 0x80 /* checkpoint process */ 134 135 136 static int sigproptbl[NSIG] = { 137 SA_KILL, /* SIGHUP */ 138 SA_KILL, /* SIGINT */ 139 SA_KILL|SA_CORE, /* SIGQUIT */ 140 SA_KILL|SA_CORE, /* SIGILL */ 141 SA_KILL|SA_CORE, /* SIGTRAP */ 142 SA_KILL|SA_CORE, /* SIGABRT */ 143 SA_KILL|SA_CORE, /* SIGEMT */ 144 SA_KILL|SA_CORE, /* SIGFPE */ 145 SA_KILL, /* SIGKILL */ 146 SA_KILL|SA_CORE, /* SIGBUS */ 147 SA_KILL|SA_CORE, /* SIGSEGV */ 148 SA_KILL|SA_CORE, /* SIGSYS */ 149 SA_KILL, /* SIGPIPE */ 150 SA_KILL, /* SIGALRM */ 151 SA_KILL, /* SIGTERM */ 152 SA_IGNORE, /* SIGURG */ 153 SA_STOP, /* SIGSTOP */ 154 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 155 SA_IGNORE|SA_CONT, /* SIGCONT */ 156 SA_IGNORE, /* SIGCHLD */ 157 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 158 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 159 SA_IGNORE, /* SIGIO */ 160 SA_KILL, /* SIGXCPU */ 161 SA_KILL, /* SIGXFSZ */ 162 SA_KILL, /* SIGVTALRM */ 163 SA_KILL, /* SIGPROF */ 164 SA_IGNORE, /* SIGWINCH */ 165 SA_IGNORE, /* SIGINFO */ 166 SA_KILL, /* SIGUSR1 */ 167 SA_KILL, /* SIGUSR2 */ 168 SA_IGNORE, /* SIGTHR */ 169 SA_CKPT, /* SIGCKPT */ 170 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 171 SA_IGNORE, 172 SA_IGNORE, 173 SA_IGNORE, 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 202 }; 203 204 static __inline int 205 sigprop(int sig) 206 { 207 208 if (sig > 0 && sig < NSIG) 209 return (sigproptbl[_SIG_IDX(sig)]); 210 return (0); 211 } 212 213 static __inline int 214 sig_ffs(sigset_t *set) 215 { 216 int i; 217 218 for (i = 0; i < _SIG_WORDS; i++) 219 if (set->__bits[i]) 220 return (ffs(set->__bits[i]) + (i * 32)); 221 return (0); 222 } 223 224 /* 225 * No requirements. 226 */ 227 int 228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 229 { 230 struct thread *td = curthread; 231 struct proc *p = td->td_proc; 232 struct lwp *lp; 233 struct sigacts *ps = p->p_sigacts; 234 235 if (sig <= 0 || sig > _SIG_MAXSIG) 236 return (EINVAL); 237 238 lwkt_gettoken(&p->p_token); 239 240 if (oact) { 241 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 242 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 243 oact->sa_flags = 0; 244 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 245 oact->sa_flags |= SA_ONSTACK; 246 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 247 oact->sa_flags |= SA_RESTART; 248 if (SIGISMEMBER(ps->ps_sigreset, sig)) 249 oact->sa_flags |= SA_RESETHAND; 250 if (SIGISMEMBER(ps->ps_signodefer, sig)) 251 oact->sa_flags |= SA_NODEFER; 252 if (SIGISMEMBER(ps->ps_siginfo, sig)) 253 oact->sa_flags |= SA_SIGINFO; 254 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 255 oact->sa_flags |= SA_NOCLDSTOP; 256 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 257 oact->sa_flags |= SA_NOCLDWAIT; 258 } 259 if (act) { 260 /* 261 * Check for invalid requests. KILL and STOP cannot be 262 * caught. 263 */ 264 if (sig == SIGKILL || sig == SIGSTOP) { 265 if (act->sa_handler != SIG_DFL) { 266 lwkt_reltoken(&p->p_token); 267 return (EINVAL); 268 } 269 } 270 271 /* 272 * Change setting atomically. 273 */ 274 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 275 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 276 if (act->sa_flags & SA_SIGINFO) { 277 ps->ps_sigact[_SIG_IDX(sig)] = 278 (__sighandler_t *)act->sa_sigaction; 279 SIGADDSET(ps->ps_siginfo, sig); 280 } else { 281 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 282 SIGDELSET(ps->ps_siginfo, sig); 283 } 284 if (!(act->sa_flags & SA_RESTART)) 285 SIGADDSET(ps->ps_sigintr, sig); 286 else 287 SIGDELSET(ps->ps_sigintr, sig); 288 if (act->sa_flags & SA_ONSTACK) 289 SIGADDSET(ps->ps_sigonstack, sig); 290 else 291 SIGDELSET(ps->ps_sigonstack, sig); 292 if (act->sa_flags & SA_RESETHAND) 293 SIGADDSET(ps->ps_sigreset, sig); 294 else 295 SIGDELSET(ps->ps_sigreset, sig); 296 if (act->sa_flags & SA_NODEFER) 297 SIGADDSET(ps->ps_signodefer, sig); 298 else 299 SIGDELSET(ps->ps_signodefer, sig); 300 if (sig == SIGCHLD) { 301 if (act->sa_flags & SA_NOCLDSTOP) 302 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 303 else 304 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 305 if (act->sa_flags & SA_NOCLDWAIT) { 306 /* 307 * Paranoia: since SA_NOCLDWAIT is implemented 308 * by reparenting the dying child to PID 1 (and 309 * trust it to reap the zombie), PID 1 itself 310 * is forbidden to set SA_NOCLDWAIT. 311 */ 312 if (p->p_pid == 1) 313 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 314 else 315 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 316 } else { 317 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 318 } 319 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 320 ps->ps_flag |= PS_CLDSIGIGN; 321 else 322 ps->ps_flag &= ~PS_CLDSIGIGN; 323 } 324 /* 325 * Set bit in p_sigignore for signals that are set to SIG_IGN, 326 * and for signals set to SIG_DFL where the default is to 327 * ignore. However, don't put SIGCONT in p_sigignore, as we 328 * have to restart the process. 329 * 330 * Also remove the signal from the process and lwp signal 331 * list. 332 */ 333 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 334 (sigprop(sig) & SA_IGNORE && 335 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 336 SIGDELSET_ATOMIC(p->p_siglist, sig); 337 FOREACH_LWP_IN_PROC(lp, p) { 338 spin_lock(&lp->lwp_spin); 339 SIGDELSET(lp->lwp_siglist, sig); 340 spin_unlock(&lp->lwp_spin); 341 } 342 if (sig != SIGCONT) { 343 /* easier in ksignal */ 344 SIGADDSET(p->p_sigignore, sig); 345 } 346 SIGDELSET(p->p_sigcatch, sig); 347 } else { 348 SIGDELSET(p->p_sigignore, sig); 349 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 350 SIGDELSET(p->p_sigcatch, sig); 351 else 352 SIGADDSET(p->p_sigcatch, sig); 353 } 354 } 355 lwkt_reltoken(&p->p_token); 356 return (0); 357 } 358 359 int 360 sys_sigaction(struct sigaction_args *uap) 361 { 362 struct sigaction act, oact; 363 struct sigaction *actp, *oactp; 364 int error; 365 366 actp = (uap->act != NULL) ? &act : NULL; 367 oactp = (uap->oact != NULL) ? &oact : NULL; 368 if (actp) { 369 error = copyin(uap->act, actp, sizeof(act)); 370 if (error) 371 return (error); 372 } 373 error = kern_sigaction(uap->sig, actp, oactp); 374 if (oactp && !error) { 375 error = copyout(oactp, uap->oact, sizeof(oact)); 376 } 377 return (error); 378 } 379 380 /* 381 * Initialize signal state for process 0; 382 * set to ignore signals that are ignored by default. 383 */ 384 void 385 siginit(struct proc *p) 386 { 387 int i; 388 389 for (i = 1; i <= NSIG; i++) 390 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 391 SIGADDSET(p->p_sigignore, i); 392 } 393 394 /* 395 * Reset signals for an exec of the specified process. 396 */ 397 void 398 execsigs(struct proc *p) 399 { 400 struct sigacts *ps = p->p_sigacts; 401 struct lwp *lp; 402 int sig; 403 404 lp = ONLY_LWP_IN_PROC(p); 405 406 /* 407 * Reset caught signals. Held signals remain held 408 * through p_sigmask (unless they were caught, 409 * and are now ignored by default). 410 */ 411 while (SIGNOTEMPTY(p->p_sigcatch)) { 412 sig = sig_ffs(&p->p_sigcatch); 413 SIGDELSET(p->p_sigcatch, sig); 414 if (sigprop(sig) & SA_IGNORE) { 415 if (sig != SIGCONT) 416 SIGADDSET(p->p_sigignore, sig); 417 SIGDELSET_ATOMIC(p->p_siglist, sig); 418 /* don't need spinlock */ 419 SIGDELSET(lp->lwp_siglist, sig); 420 } 421 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 422 } 423 424 /* 425 * Reset stack state to the user stack. 426 * Clear set of signals caught on the signal stack. 427 */ 428 lp->lwp_sigstk.ss_flags = SS_DISABLE; 429 lp->lwp_sigstk.ss_size = 0; 430 lp->lwp_sigstk.ss_sp = NULL; 431 lp->lwp_flags &= ~LWP_ALTSTACK; 432 /* 433 * Reset no zombies if child dies flag as Solaris does. 434 */ 435 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 436 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 437 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 438 } 439 440 /* 441 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 442 * 443 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 444 * p == curproc. 445 */ 446 int 447 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 448 { 449 struct thread *td = curthread; 450 struct lwp *lp = td->td_lwp; 451 struct proc *p = td->td_proc; 452 int error; 453 454 lwkt_gettoken(&p->p_token); 455 456 if (oset != NULL) 457 *oset = lp->lwp_sigmask; 458 459 error = 0; 460 if (set != NULL) { 461 switch (how) { 462 case SIG_BLOCK: 463 SIG_CANTMASK(*set); 464 SIGSETOR(lp->lwp_sigmask, *set); 465 break; 466 case SIG_UNBLOCK: 467 SIGSETNAND(lp->lwp_sigmask, *set); 468 break; 469 case SIG_SETMASK: 470 SIG_CANTMASK(*set); 471 lp->lwp_sigmask = *set; 472 break; 473 default: 474 error = EINVAL; 475 break; 476 } 477 } 478 479 lwkt_reltoken(&p->p_token); 480 481 return (error); 482 } 483 484 /* 485 * sigprocmask() 486 * 487 * MPSAFE 488 */ 489 int 490 sys_sigprocmask(struct sigprocmask_args *uap) 491 { 492 sigset_t set, oset; 493 sigset_t *setp, *osetp; 494 int error; 495 496 setp = (uap->set != NULL) ? &set : NULL; 497 osetp = (uap->oset != NULL) ? &oset : NULL; 498 if (setp) { 499 error = copyin(uap->set, setp, sizeof(set)); 500 if (error) 501 return (error); 502 } 503 error = kern_sigprocmask(uap->how, setp, osetp); 504 if (osetp && !error) { 505 error = copyout(osetp, uap->oset, sizeof(oset)); 506 } 507 return (error); 508 } 509 510 /* 511 * MPSAFE 512 */ 513 int 514 kern_sigpending(struct __sigset *set) 515 { 516 struct lwp *lp = curthread->td_lwp; 517 518 *set = lwp_sigpend(lp); 519 520 return (0); 521 } 522 523 /* 524 * MPSAFE 525 */ 526 int 527 sys_sigpending(struct sigpending_args *uap) 528 { 529 sigset_t set; 530 int error; 531 532 error = kern_sigpending(&set); 533 534 if (error == 0) 535 error = copyout(&set, uap->set, sizeof(set)); 536 return (error); 537 } 538 539 /* 540 * Suspend process until signal, providing mask to be set 541 * in the meantime. 542 * 543 * MPSAFE 544 */ 545 int 546 kern_sigsuspend(struct __sigset *set) 547 { 548 struct thread *td = curthread; 549 struct lwp *lp = td->td_lwp; 550 struct proc *p = td->td_proc; 551 struct sigacts *ps = p->p_sigacts; 552 553 /* 554 * When returning from sigsuspend, we want 555 * the old mask to be restored after the 556 * signal handler has finished. Thus, we 557 * save it here and mark the sigacts structure 558 * to indicate this. 559 */ 560 lp->lwp_oldsigmask = lp->lwp_sigmask; 561 lp->lwp_flags |= LWP_OLDMASK; 562 563 SIG_CANTMASK(*set); 564 lp->lwp_sigmask = *set; 565 while (tsleep(ps, PCATCH, "pause", 0) == 0) 566 /* void */; 567 /* always return EINTR rather than ERESTART... */ 568 return (EINTR); 569 } 570 571 /* 572 * Note nonstandard calling convention: libc stub passes mask, not 573 * pointer, to save a copyin. 574 * 575 * MPSAFE 576 */ 577 int 578 sys_sigsuspend(struct sigsuspend_args *uap) 579 { 580 sigset_t mask; 581 int error; 582 583 error = copyin(uap->sigmask, &mask, sizeof(mask)); 584 if (error) 585 return (error); 586 587 error = kern_sigsuspend(&mask); 588 589 return (error); 590 } 591 592 /* 593 * MPSAFE 594 */ 595 int 596 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 597 { 598 struct thread *td = curthread; 599 struct lwp *lp = td->td_lwp; 600 struct proc *p = td->td_proc; 601 602 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 603 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 604 605 if (oss) 606 *oss = lp->lwp_sigstk; 607 608 if (ss) { 609 if (ss->ss_flags & ~SS_DISABLE) 610 return (EINVAL); 611 if (ss->ss_flags & SS_DISABLE) { 612 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 613 return (EPERM); 614 lp->lwp_flags &= ~LWP_ALTSTACK; 615 lp->lwp_sigstk.ss_flags = ss->ss_flags; 616 } else { 617 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 618 return (ENOMEM); 619 lp->lwp_flags |= LWP_ALTSTACK; 620 lp->lwp_sigstk = *ss; 621 } 622 } 623 624 return (0); 625 } 626 627 /* 628 * MPSAFE 629 */ 630 int 631 sys_sigaltstack(struct sigaltstack_args *uap) 632 { 633 stack_t ss, oss; 634 int error; 635 636 if (uap->ss) { 637 error = copyin(uap->ss, &ss, sizeof(ss)); 638 if (error) 639 return (error); 640 } 641 642 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); 643 644 if (error == 0 && uap->oss) 645 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 646 return (error); 647 } 648 649 /* 650 * Common code for kill process group/broadcast kill. 651 * cp is calling process. 652 */ 653 struct killpg_info { 654 int nfound; 655 int sig; 656 }; 657 658 static int killpg_all_callback(struct proc *p, void *data); 659 660 static int 661 dokillpg(int sig, int pgid, int all) 662 { 663 struct killpg_info info; 664 struct proc *cp = curproc; 665 struct proc *p; 666 struct pgrp *pgrp; 667 668 info.nfound = 0; 669 info.sig = sig; 670 671 if (all) { 672 /* 673 * broadcast 674 */ 675 allproc_scan(killpg_all_callback, &info); 676 } else { 677 if (pgid == 0) { 678 /* 679 * zero pgid means send to my process group. 680 */ 681 pgrp = cp->p_pgrp; 682 pgref(pgrp); 683 } else { 684 pgrp = pgfind(pgid); 685 if (pgrp == NULL) 686 return (ESRCH); 687 } 688 689 /* 690 * Must interlock all signals against fork 691 */ 692 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 693 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 694 if (p->p_pid <= 1 || 695 p->p_stat == SZOMB || 696 (p->p_flags & P_SYSTEM) || 697 !CANSIGNAL(p, sig)) { 698 continue; 699 } 700 ++info.nfound; 701 if (sig) 702 ksignal(p, sig); 703 } 704 lockmgr(&pgrp->pg_lock, LK_RELEASE); 705 pgrel(pgrp); 706 } 707 return (info.nfound ? 0 : ESRCH); 708 } 709 710 static int 711 killpg_all_callback(struct proc *p, void *data) 712 { 713 struct killpg_info *info = data; 714 715 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 716 p == curproc || !CANSIGNAL(p, info->sig)) { 717 return (0); 718 } 719 ++info->nfound; 720 if (info->sig) 721 ksignal(p, info->sig); 722 return(0); 723 } 724 725 /* 726 * Send a general signal to a process or LWPs within that process. 727 * 728 * Note that new signals cannot be sent if a process is exiting or already 729 * a zombie, but we return success anyway as userland is likely to not handle 730 * the race properly. 731 * 732 * No requirements. 733 */ 734 int 735 kern_kill(int sig, pid_t pid, lwpid_t tid) 736 { 737 int t; 738 739 if ((u_int)sig > _SIG_MAXSIG) 740 return (EINVAL); 741 742 if (pid > 0) { 743 struct proc *p; 744 struct lwp *lp = NULL; 745 746 /* 747 * Send a signal to a single process. If the kill() is 748 * racing an exiting process which has not yet been reaped 749 * act as though the signal was delivered successfully but 750 * don't actually try to deliver the signal. 751 */ 752 if ((p = pfind(pid)) == NULL) { 753 if ((p = zpfind(pid)) == NULL) 754 return (ESRCH); 755 PRELE(p); 756 return (0); 757 } 758 if (p != curproc) { 759 lwkt_gettoken_shared(&p->p_token); 760 if (!CANSIGNAL(p, sig)) { 761 lwkt_reltoken(&p->p_token); 762 PRELE(p); 763 return (EPERM); 764 } 765 lwkt_reltoken(&p->p_token); 766 } 767 768 /* 769 * NOP if the process is exiting. Note that lwpsignal() is 770 * called directly with P_WEXIT set to kill individual LWPs 771 * during exit, which is allowed. 772 */ 773 if (p->p_flags & P_WEXIT) { 774 PRELE(p); 775 return (0); 776 } 777 if (tid != -1) { 778 lwkt_gettoken_shared(&p->p_token); 779 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 780 if (lp == NULL) { 781 lwkt_reltoken(&p->p_token); 782 PRELE(p); 783 return (ESRCH); 784 } 785 LWPHOLD(lp); 786 lwkt_reltoken(&p->p_token); 787 } 788 if (sig) 789 lwpsignal(p, lp, sig); 790 if (lp) 791 LWPRELE(lp); 792 PRELE(p); 793 794 return (0); 795 } 796 797 /* 798 * If we come here, pid is a special broadcast pid. 799 * This doesn't mix with a tid. 800 */ 801 if (tid != -1) 802 return (EINVAL); 803 804 switch (pid) { 805 case -1: /* broadcast signal */ 806 t = (dokillpg(sig, 0, 1)); 807 break; 808 case 0: /* signal own process group */ 809 t = (dokillpg(sig, 0, 0)); 810 break; 811 default: /* negative explicit process group */ 812 t = (dokillpg(sig, -pid, 0)); 813 break; 814 } 815 return t; 816 } 817 818 int 819 sys_kill(struct kill_args *uap) 820 { 821 int error; 822 823 error = kern_kill(uap->signum, uap->pid, -1); 824 return (error); 825 } 826 827 int 828 sys_lwp_kill(struct lwp_kill_args *uap) 829 { 830 int error; 831 pid_t pid = uap->pid; 832 833 /* 834 * A tid is mandatory for lwp_kill(), otherwise 835 * you could simply use kill(). 836 */ 837 if (uap->tid == -1) 838 return (EINVAL); 839 840 /* 841 * To save on a getpid() function call for intra-process 842 * signals, pid == -1 means current process. 843 */ 844 if (pid == -1) 845 pid = curproc->p_pid; 846 847 error = kern_kill(uap->signum, pid, uap->tid); 848 return (error); 849 } 850 851 /* 852 * Send a signal to a process group. 853 */ 854 void 855 gsignal(int pgid, int sig) 856 { 857 struct pgrp *pgrp; 858 859 if (pgid && (pgrp = pgfind(pgid))) 860 pgsignal(pgrp, sig, 0); 861 } 862 863 /* 864 * Send a signal to a process group. If checktty is 1, 865 * limit to members which have a controlling terminal. 866 * 867 * pg_lock interlocks against a fork that might be in progress, to 868 * ensure that the new child process picks up the signal. 869 */ 870 void 871 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 872 { 873 struct proc *p; 874 875 /* 876 * Must interlock all signals against fork 877 */ 878 if (pgrp) { 879 pgref(pgrp); 880 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 881 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 882 if (checkctty == 0 || p->p_flags & P_CONTROLT) 883 ksignal(p, sig); 884 } 885 lockmgr(&pgrp->pg_lock, LK_RELEASE); 886 pgrel(pgrp); 887 } 888 } 889 890 /* 891 * Send a signal caused by a trap to the current lwp. If it will be caught 892 * immediately, deliver it with correct code. Otherwise, post it normally. 893 * 894 * These signals may ONLY be delivered to the specified lwp and may never 895 * be delivered to the process generically. 896 */ 897 void 898 trapsignal(struct lwp *lp, int sig, u_long code) 899 { 900 struct proc *p = lp->lwp_proc; 901 struct sigacts *ps = p->p_sigacts; 902 903 /* 904 * If we are a virtual kernel running an emulated user process 905 * context, switch back to the virtual kernel context before 906 * trying to post the signal. 907 */ 908 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 909 struct trapframe *tf = lp->lwp_md.md_regs; 910 tf->tf_trapno = 0; 911 vkernel_trap(lp, tf); 912 } 913 914 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 915 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 916 lp->lwp_ru.ru_nsignals++; 917 #ifdef KTRACE 918 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 919 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 920 &lp->lwp_sigmask, code); 921 #endif 922 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 923 &lp->lwp_sigmask, code); 924 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 925 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 926 SIGADDSET(lp->lwp_sigmask, sig); 927 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 928 /* 929 * See kern_sigaction() for origin of this code. 930 */ 931 SIGDELSET(p->p_sigcatch, sig); 932 if (sig != SIGCONT && 933 sigprop(sig) & SA_IGNORE) 934 SIGADDSET(p->p_sigignore, sig); 935 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 936 } 937 } else { 938 lp->lwp_code = code; /* XXX for core dump/debugger */ 939 lp->lwp_sig = sig; /* XXX to verify code */ 940 lwpsignal(p, lp, sig); 941 } 942 } 943 944 /* 945 * Find a suitable lwp to deliver the signal to. Returns NULL if all 946 * lwps hold the signal blocked. 947 * 948 * Caller must hold p->p_token. 949 * 950 * Returns a lp or NULL. If non-NULL the lp is held and its token is 951 * acquired. 952 */ 953 static struct lwp * 954 find_lwp_for_signal(struct proc *p, int sig) 955 { 956 struct lwp *lp; 957 struct lwp *run, *sleep, *stop; 958 959 /* 960 * If the running/preempted thread belongs to the proc to which 961 * the signal is being delivered and this thread does not block 962 * the signal, then we can avoid a context switch by delivering 963 * the signal to this thread, because it will return to userland 964 * soon anyways. 965 */ 966 lp = lwkt_preempted_proc(); 967 if (lp != NULL && lp->lwp_proc == p) { 968 LWPHOLD(lp); 969 lwkt_gettoken(&lp->lwp_token); 970 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 971 /* return w/ token held */ 972 return (lp); 973 } 974 lwkt_reltoken(&lp->lwp_token); 975 LWPRELE(lp); 976 } 977 978 run = sleep = stop = NULL; 979 FOREACH_LWP_IN_PROC(lp, p) { 980 /* 981 * If the signal is being blocked by the lwp, then this 982 * lwp is not eligible for receiving the signal. 983 */ 984 LWPHOLD(lp); 985 lwkt_gettoken(&lp->lwp_token); 986 987 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 988 lwkt_reltoken(&lp->lwp_token); 989 LWPRELE(lp); 990 continue; 991 } 992 993 switch (lp->lwp_stat) { 994 case LSRUN: 995 if (sleep) { 996 lwkt_token_swap(); 997 lwkt_reltoken(&sleep->lwp_token); 998 LWPRELE(sleep); 999 sleep = NULL; 1000 run = lp; 1001 } else if (stop) { 1002 lwkt_token_swap(); 1003 lwkt_reltoken(&stop->lwp_token); 1004 LWPRELE(stop); 1005 stop = NULL; 1006 run = lp; 1007 } else { 1008 run = lp; 1009 } 1010 break; 1011 case LSSLEEP: 1012 if (lp->lwp_flags & LWP_SINTR) { 1013 if (sleep) { 1014 lwkt_reltoken(&lp->lwp_token); 1015 LWPRELE(lp); 1016 } else if (stop) { 1017 lwkt_token_swap(); 1018 lwkt_reltoken(&stop->lwp_token); 1019 LWPRELE(stop); 1020 stop = NULL; 1021 sleep = lp; 1022 } else { 1023 sleep = lp; 1024 } 1025 } else { 1026 lwkt_reltoken(&lp->lwp_token); 1027 LWPRELE(lp); 1028 } 1029 break; 1030 case LSSTOP: 1031 if (sleep) { 1032 lwkt_reltoken(&lp->lwp_token); 1033 LWPRELE(lp); 1034 } else if (stop) { 1035 lwkt_reltoken(&lp->lwp_token); 1036 LWPRELE(lp); 1037 } else { 1038 stop = lp; 1039 } 1040 break; 1041 } 1042 if (run) 1043 break; 1044 } 1045 1046 if (run != NULL) 1047 return (run); 1048 else if (sleep != NULL) 1049 return (sleep); 1050 else 1051 return (stop); 1052 } 1053 1054 /* 1055 * Send the signal to the process. If the signal has an action, the action 1056 * is usually performed by the target process rather than the caller; we add 1057 * the signal to the set of pending signals for the process. 1058 * 1059 * Exceptions: 1060 * o When a stop signal is sent to a sleeping process that takes the 1061 * default action, the process is stopped without awakening it. 1062 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1063 * regardless of the signal action (eg, blocked or ignored). 1064 * 1065 * Other ignored signals are discarded immediately. 1066 * 1067 * If the caller wishes to call this function from a hard code section the 1068 * caller must already hold p->p_token (see kern_clock.c). 1069 * 1070 * No requirements. 1071 */ 1072 void 1073 ksignal(struct proc *p, int sig) 1074 { 1075 lwpsignal(p, NULL, sig); 1076 } 1077 1078 /* 1079 * The core for ksignal. lp may be NULL, then a suitable thread 1080 * will be chosen. If not, lp MUST be a member of p. 1081 * 1082 * If the caller wishes to call this function from a hard code section the 1083 * caller must already hold p->p_token. 1084 * 1085 * No requirements. 1086 */ 1087 void 1088 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1089 { 1090 struct proc *q; 1091 sig_t action; 1092 int prop; 1093 1094 if (sig > _SIG_MAXSIG || sig <= 0) { 1095 kprintf("lwpsignal: signal %d\n", sig); 1096 panic("lwpsignal signal number"); 1097 } 1098 1099 KKASSERT(lp == NULL || lp->lwp_proc == p); 1100 1101 /* 1102 * We don't want to race... well, all sorts of things. Get appropriate 1103 * tokens. 1104 * 1105 * Don't try to deliver a generic signal to an exiting process, 1106 * the signal structures could be in flux. We check the LWP later 1107 * on. 1108 */ 1109 PHOLD(p); 1110 if (lp) { 1111 LWPHOLD(lp); 1112 lwkt_gettoken(&lp->lwp_token); 1113 } else { 1114 lwkt_gettoken(&p->p_token); 1115 if (p->p_flags & P_WEXIT) 1116 goto out; 1117 } 1118 1119 prop = sigprop(sig); 1120 1121 /* 1122 * If proc is traced, always give parent a chance; 1123 * if signal event is tracked by procfs, give *that* 1124 * a chance, as well. 1125 */ 1126 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1127 action = SIG_DFL; 1128 } else { 1129 /* 1130 * Do not try to deliver signals to an exiting lwp other 1131 * than SIGKILL. Note that we must still deliver the signal 1132 * if P_WEXIT is set in the process flags. 1133 */ 1134 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { 1135 lwkt_reltoken(&lp->lwp_token); 1136 LWPRELE(lp); 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 } else { 1156 lwkt_reltoken(&p->p_token); 1157 } 1158 PRELE(p); 1159 return; 1160 } 1161 if (SIGISMEMBER(p->p_sigcatch, sig)) 1162 action = SIG_CATCH; 1163 else 1164 action = SIG_DFL; 1165 } 1166 1167 /* 1168 * If continuing, clear any pending STOP signals for the whole 1169 * process. 1170 */ 1171 if (prop & SA_CONT) { 1172 lwkt_gettoken(&p->p_token); 1173 SIG_STOPSIGMASK_ATOMIC(p->p_siglist); 1174 lwkt_reltoken(&p->p_token); 1175 } 1176 1177 if (prop & SA_STOP) { 1178 /* 1179 * If sending a tty stop signal to a member of an orphaned 1180 * process group, discard the signal here if the action 1181 * is default; don't stop the process below if sleeping, 1182 * and don't clear any pending SIGCONT. 1183 */ 1184 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && 1185 action == SIG_DFL) { 1186 if (lp) { 1187 lwkt_reltoken(&lp->lwp_token); 1188 LWPRELE(lp); 1189 } else { 1190 lwkt_reltoken(&p->p_token); 1191 } 1192 PRELE(p); 1193 return; 1194 } 1195 lwkt_gettoken(&p->p_token); 1196 SIG_CONTSIGMASK_ATOMIC(p->p_siglist); 1197 p->p_flags &= ~P_CONTINUED; 1198 lwkt_reltoken(&p->p_token); 1199 } 1200 1201 if (p->p_stat == SSTOP) { 1202 /* 1203 * Nobody can handle this signal, add it to the lwp or 1204 * process pending list 1205 */ 1206 lwkt_gettoken(&p->p_token); 1207 if (p->p_stat != SSTOP) { 1208 lwkt_reltoken(&p->p_token); 1209 goto not_stopped; 1210 } 1211 if (lp) { 1212 spin_lock(&lp->lwp_spin); 1213 SIGADDSET(lp->lwp_siglist, sig); 1214 spin_unlock(&lp->lwp_spin); 1215 } else { 1216 SIGADDSET_ATOMIC(p->p_siglist, sig); 1217 } 1218 1219 /* 1220 * If the process is stopped and is being traced, then no 1221 * further action is necessary. 1222 */ 1223 if (p->p_flags & P_TRACED) { 1224 lwkt_reltoken(&p->p_token); 1225 goto out; 1226 } 1227 1228 /* 1229 * If the process is stopped and receives a KILL signal, 1230 * make the process runnable. 1231 */ 1232 if (sig == SIGKILL) { 1233 proc_unstop(p, SSTOP); 1234 lwkt_reltoken(&p->p_token); 1235 goto active_process; 1236 } 1237 1238 /* 1239 * If the process is stopped and receives a CONT signal, 1240 * then try to make the process runnable again. 1241 */ 1242 if (prop & SA_CONT) { 1243 /* 1244 * If SIGCONT is default (or ignored), we continue the 1245 * process but don't leave the signal in p_siglist, as 1246 * it has no further action. If SIGCONT is held, we 1247 * continue the process and leave the signal in 1248 * p_siglist. If the process catches SIGCONT, let it 1249 * handle the signal itself. 1250 * 1251 * XXX what if the signal is being held blocked? 1252 * 1253 * Token required to interlock kern_wait(). 1254 * Reparenting can also cause a race so we have to 1255 * hold (q). 1256 */ 1257 q = p->p_pptr; 1258 PHOLD(q); 1259 lwkt_gettoken(&q->p_token); 1260 p->p_flags |= P_CONTINUED; 1261 wakeup(q); 1262 if (action == SIG_DFL) 1263 SIGDELSET_ATOMIC(p->p_siglist, sig); 1264 proc_unstop(p, SSTOP); 1265 lwkt_reltoken(&q->p_token); 1266 PRELE(q); 1267 lwkt_reltoken(&p->p_token); 1268 if (action == SIG_CATCH) 1269 goto active_process; 1270 goto out; 1271 } 1272 1273 /* 1274 * If the process is stopped and receives another STOP 1275 * signal, we do not need to stop it again. If we did 1276 * the shell could get confused. 1277 * 1278 * However, if the current/preempted lwp is part of the 1279 * process receiving the signal, we need to keep it, 1280 * so that this lwp can stop in issignal() later, as 1281 * we don't want to wait until it reaches userret! 1282 */ 1283 if (prop & SA_STOP) { 1284 if (lwkt_preempted_proc() == NULL || 1285 lwkt_preempted_proc()->lwp_proc != p) { 1286 SIGDELSET_ATOMIC(p->p_siglist, sig); 1287 } 1288 } 1289 1290 /* 1291 * Otherwise the process is stopped and it received some 1292 * signal, which does not change its stopped state. When 1293 * the process is continued a wakeup(p) will be issued which 1294 * will wakeup any threads sleeping in tstop(). 1295 */ 1296 lwkt_reltoken(&p->p_token); 1297 goto out; 1298 /* NOTREACHED */ 1299 } 1300 not_stopped: 1301 ; 1302 /* else not stopped */ 1303 active_process: 1304 1305 /* 1306 * Never deliver a lwp-specific signal to a random lwp. 1307 */ 1308 if (lp == NULL) { 1309 /* NOTE: returns lp w/ token held */ 1310 lp = find_lwp_for_signal(p, sig); 1311 if (lp) { 1312 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1313 lwkt_reltoken(&lp->lwp_token); 1314 LWPRELE(lp); 1315 lp = NULL; 1316 /* maintain proc token */ 1317 } else { 1318 lwkt_token_swap(); 1319 lwkt_reltoken(&p->p_token); 1320 /* maintain lp token */ 1321 } 1322 } 1323 } 1324 1325 /* 1326 * Deliver to the process generically if (1) the signal is being 1327 * sent to any thread or (2) we could not find a thread to deliver 1328 * it to. 1329 */ 1330 if (lp == NULL) { 1331 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1332 SIGADDSET_ATOMIC(p->p_siglist, sig); 1333 goto out; 1334 } 1335 1336 /* 1337 * Deliver to a specific LWP whether it masks it or not. It will 1338 * not be dispatched if masked but we must still deliver it. 1339 */ 1340 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1341 (p->p_flags & P_TRACED) == 0) { 1342 lwkt_gettoken(&p->p_token); 1343 p->p_nice = NZERO; 1344 lwkt_reltoken(&p->p_token); 1345 } 1346 1347 /* 1348 * If the process receives a STOP signal which indeed needs to 1349 * stop the process, do so. If the process chose to catch the 1350 * signal, it will be treated like any other signal. 1351 */ 1352 if ((prop & SA_STOP) && action == SIG_DFL) { 1353 /* 1354 * If a child holding parent blocked, stopping 1355 * could cause deadlock. Take no action at this 1356 * time. 1357 */ 1358 lwkt_gettoken(&p->p_token); 1359 if (p->p_flags & P_PPWAIT) { 1360 SIGADDSET_ATOMIC(p->p_siglist, sig); 1361 lwkt_reltoken(&p->p_token); 1362 goto out; 1363 } 1364 1365 /* 1366 * Do not actually try to manipulate the process, but simply 1367 * stop it. Lwps will stop as soon as they safely can. 1368 * 1369 * Ignore stop if the process is exiting. 1370 */ 1371 if ((p->p_flags & P_WEXIT) == 0) { 1372 p->p_xstat = sig; 1373 proc_stop(p, SSTOP); 1374 } 1375 lwkt_reltoken(&p->p_token); 1376 goto out; 1377 } 1378 1379 /* 1380 * If it is a CONT signal with default action, just ignore it. 1381 */ 1382 if ((prop & SA_CONT) && action == SIG_DFL) 1383 goto out; 1384 1385 /* 1386 * Mark signal pending at this specific thread. 1387 */ 1388 spin_lock(&lp->lwp_spin); 1389 SIGADDSET(lp->lwp_siglist, sig); 1390 spin_unlock(&lp->lwp_spin); 1391 1392 lwp_signotify(lp); 1393 1394 out: 1395 if (lp) { 1396 lwkt_reltoken(&lp->lwp_token); 1397 LWPRELE(lp); 1398 } else { 1399 lwkt_reltoken(&p->p_token); 1400 } 1401 PRELE(p); 1402 } 1403 1404 /* 1405 * Notify the LWP that a signal has arrived. The LWP does not have to be 1406 * sleeping on the current cpu. 1407 * 1408 * p->p_token and lp->lwp_token must be held on call. 1409 * 1410 * We can only safely schedule the thread on its current cpu and only if 1411 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1412 * the correct cpu we are properly interlocked, otherwise we could be 1413 * racing other thread transition states (or the lwp is on the user scheduler 1414 * runq but not scheduled) and must not do anything. 1415 * 1416 * Since we hold the lwp token we know the lwp cannot be ripped out from 1417 * under us so we can safely hold it to prevent it from being ripped out 1418 * from under us if we are forced to IPI another cpu to make the local 1419 * checks there. 1420 * 1421 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1422 * which we won't in an IPI so any fixups have to be done here, effectively 1423 * replicating part of what setrunnable() does. 1424 */ 1425 static void 1426 lwp_signotify(struct lwp *lp) 1427 { 1428 thread_t dtd; 1429 1430 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1431 dtd = lp->lwp_thread; 1432 1433 crit_enter(); 1434 if (lp == lwkt_preempted_proc()) { 1435 /* 1436 * lwp is on the current cpu AND it is currently running 1437 * (we preempted it). 1438 */ 1439 signotify(); 1440 } else if (lp->lwp_flags & LWP_SINTR) { 1441 /* 1442 * lwp is sitting in tsleep() with PCATCH set 1443 */ 1444 if (dtd->td_gd == mycpu) { 1445 setrunnable(lp); 1446 } else { 1447 /* 1448 * We can only adjust lwp_stat while we hold the 1449 * lwp_token, and we won't in the IPI function. 1450 */ 1451 LWPHOLD(lp); 1452 if (lp->lwp_stat == LSSTOP) 1453 lp->lwp_stat = LSSLEEP; 1454 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1455 } 1456 } else if (dtd->td_flags & TDF_SINTR) { 1457 /* 1458 * lwp is sitting in lwkt_sleep() with PCATCH set. 1459 */ 1460 if (dtd->td_gd == mycpu) { 1461 setrunnable(lp); 1462 } else { 1463 /* 1464 * We can only adjust lwp_stat while we hold the 1465 * lwp_token, and we won't in the IPI function. 1466 */ 1467 LWPHOLD(lp); 1468 if (lp->lwp_stat == LSSTOP) 1469 lp->lwp_stat = LSSLEEP; 1470 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1471 } 1472 } else { 1473 /* 1474 * Otherwise the lwp is either in some uninterruptible state 1475 * or it is on the userland scheduler's runqueue waiting to 1476 * be scheduled to a cpu, or it is running in userland. We 1477 * generally want to send an IPI so a running target gets the 1478 * signal ASAP, otherwise a scheduler-tick worth of latency 1479 * will occur. 1480 * 1481 * Issue an IPI to the remote cpu to knock it into the kernel, 1482 * remote cpu will issue the cpu-local signotify() if the IPI 1483 * preempts the desired thread. 1484 */ 1485 if (dtd->td_gd != mycpu) { 1486 LWPHOLD(lp); 1487 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1488 } 1489 } 1490 crit_exit(); 1491 } 1492 1493 /* 1494 * This function is called via an IPI so we cannot call setrunnable() here 1495 * (because while we hold the lp we don't own its token, and can't get it 1496 * from an IPI). 1497 * 1498 * We are interlocked by virtue of being on the same cpu as the target. If 1499 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1500 * the target thread. 1501 */ 1502 static void 1503 lwp_signotify_remote(void *arg) 1504 { 1505 struct lwp *lp = arg; 1506 thread_t td = lp->lwp_thread; 1507 1508 if (lp == lwkt_preempted_proc()) { 1509 signotify(); 1510 LWPRELE(lp); 1511 } else if (td->td_gd == mycpu) { 1512 if ((lp->lwp_flags & LWP_SINTR) || 1513 (td->td_flags & TDF_SINTR)) { 1514 lwkt_schedule(td); 1515 } 1516 LWPRELE(lp); 1517 } else { 1518 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1519 /* LWPHOLD() is forwarded to the target cpu */ 1520 } 1521 } 1522 1523 /* 1524 * Caller must hold p->p_token 1525 */ 1526 void 1527 proc_stop(struct proc *p, int sig) 1528 { 1529 struct proc *q; 1530 struct lwp *lp; 1531 1532 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1533 1534 /* 1535 * If somebody raced us, be happy with it. SCORE overrides SSTOP. 1536 */ 1537 if (sig == SCORE) { 1538 if (p->p_stat == SCORE || p->p_stat == SZOMB) 1539 return; 1540 } else { 1541 if (p->p_stat == SSTOP || p->p_stat == SCORE || 1542 p->p_stat == SZOMB) { 1543 return; 1544 } 1545 } 1546 p->p_stat = sig; 1547 1548 FOREACH_LWP_IN_PROC(lp, p) { 1549 LWPHOLD(lp); 1550 lwkt_gettoken(&lp->lwp_token); 1551 1552 switch (lp->lwp_stat) { 1553 case LSSTOP: 1554 /* 1555 * Do nothing, we are already counted in 1556 * p_nstopped. 1557 */ 1558 break; 1559 1560 case LSSLEEP: 1561 /* 1562 * We're sleeping, but we will stop before 1563 * returning to userspace, so count us 1564 * as stopped as well. We set LWP_MP_WSTOP 1565 * to signal the lwp that it should not 1566 * increase p_nstopped when reaching tstop(). 1567 * 1568 * LWP_MP_WSTOP is protected by lp->lwp_token. 1569 */ 1570 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1571 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1572 ++p->p_nstopped; 1573 } 1574 break; 1575 1576 case LSRUN: 1577 /* 1578 * We might notify ourself, but that's not 1579 * a problem. 1580 */ 1581 lwp_signotify(lp); 1582 break; 1583 } 1584 lwkt_reltoken(&lp->lwp_token); 1585 LWPRELE(lp); 1586 } 1587 1588 if (p->p_nstopped == p->p_nthreads) { 1589 /* 1590 * Token required to interlock kern_wait(). Reparenting can 1591 * also cause a race so we have to hold (q). 1592 */ 1593 q = p->p_pptr; 1594 PHOLD(q); 1595 lwkt_gettoken(&q->p_token); 1596 p->p_flags &= ~P_WAITED; 1597 wakeup(q); 1598 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1599 ksignal(p->p_pptr, SIGCHLD); 1600 lwkt_reltoken(&q->p_token); 1601 PRELE(q); 1602 } 1603 } 1604 1605 /* 1606 * Caller must hold p_token 1607 */ 1608 void 1609 proc_unstop(struct proc *p, int sig) 1610 { 1611 struct lwp *lp; 1612 1613 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1614 1615 if (p->p_stat != sig) 1616 return; 1617 1618 p->p_stat = SACTIVE; 1619 1620 FOREACH_LWP_IN_PROC(lp, p) { 1621 LWPHOLD(lp); 1622 lwkt_gettoken(&lp->lwp_token); 1623 1624 switch (lp->lwp_stat) { 1625 case LSRUN: 1626 /* 1627 * Uh? Not stopped? Well, I guess that's okay. 1628 */ 1629 if (bootverbose) 1630 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1631 p->p_pid, lp->lwp_tid); 1632 break; 1633 1634 case LSSLEEP: 1635 /* 1636 * Still sleeping. Don't bother waking it up. 1637 * However, if this thread was counted as 1638 * stopped, undo this. 1639 * 1640 * Nevertheless we call setrunnable() so that it 1641 * will wake up in case a signal or timeout arrived 1642 * in the meantime. 1643 * 1644 * LWP_MP_WSTOP is protected by lp->lwp_token. 1645 */ 1646 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1647 atomic_clear_int(&lp->lwp_mpflags, 1648 LWP_MP_WSTOP); 1649 --p->p_nstopped; 1650 } else { 1651 if (bootverbose) 1652 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1653 p->p_pid, lp->lwp_tid); 1654 } 1655 /* FALLTHROUGH */ 1656 1657 case LSSTOP: 1658 /* 1659 * This handles any lwp's waiting in a tsleep with 1660 * SIGCATCH. 1661 */ 1662 lwp_signotify(lp); 1663 break; 1664 1665 } 1666 lwkt_reltoken(&lp->lwp_token); 1667 LWPRELE(lp); 1668 } 1669 1670 /* 1671 * This handles any lwp's waiting in tstop(). We have interlocked 1672 * the setting of p_stat by acquiring and releasing each lpw's 1673 * token. 1674 */ 1675 wakeup(p); 1676 } 1677 1678 /* 1679 * Wait for all threads except the current thread to stop. 1680 */ 1681 static void 1682 proc_stopwait(struct proc *p) 1683 { 1684 while ((p->p_stat == SSTOP || p->p_stat == SCORE) && 1685 p->p_nstopped < p->p_nthreads - 1) { 1686 tsleep_interlock(&p->p_nstopped, 0); 1687 if (p->p_nstopped < p->p_nthreads - 1) { 1688 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); 1689 } 1690 } 1691 } 1692 1693 /* 1694 * No requirements. 1695 */ 1696 static int 1697 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1698 { 1699 sigset_t savedmask, set; 1700 struct proc *p = curproc; 1701 struct lwp *lp = curthread->td_lwp; 1702 int error, sig, hz, timevalid = 0; 1703 struct timespec rts, ets, ts; 1704 struct timeval tv; 1705 1706 error = 0; 1707 sig = 0; 1708 ets.tv_sec = 0; /* silence compiler warning */ 1709 ets.tv_nsec = 0; /* silence compiler warning */ 1710 SIG_CANTMASK(waitset); 1711 savedmask = lp->lwp_sigmask; 1712 1713 if (timeout) { 1714 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1715 timeout->tv_nsec < 1000000000) { 1716 timevalid = 1; 1717 getnanouptime(&rts); 1718 ets = rts; 1719 timespecadd(&ets, timeout); 1720 } 1721 } 1722 1723 for (;;) { 1724 set = lwp_sigpend(lp); 1725 SIGSETAND(set, waitset); 1726 if ((sig = sig_ffs(&set)) != 0) { 1727 SIGFILLSET(lp->lwp_sigmask); 1728 SIGDELSET(lp->lwp_sigmask, sig); 1729 SIG_CANTMASK(lp->lwp_sigmask); 1730 sig = issignal(lp, 1, 0); 1731 /* 1732 * It may be a STOP signal, in the case, issignal 1733 * returns 0, because we may stop there, and new 1734 * signal can come in, we should restart if we got 1735 * nothing. 1736 */ 1737 if (sig == 0) 1738 continue; 1739 else 1740 break; 1741 } 1742 1743 /* 1744 * Previous checking got nothing, and we retried but still 1745 * got nothing, we should return the error status. 1746 */ 1747 if (error) 1748 break; 1749 1750 /* 1751 * POSIX says this must be checked after looking for pending 1752 * signals. 1753 */ 1754 if (timeout) { 1755 if (timevalid == 0) { 1756 error = EINVAL; 1757 break; 1758 } 1759 getnanouptime(&rts); 1760 if (timespeccmp(&rts, &ets, >=)) { 1761 error = EAGAIN; 1762 break; 1763 } 1764 ts = ets; 1765 timespecsub(&ts, &rts); 1766 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1767 hz = tvtohz_high(&tv); 1768 } else { 1769 hz = 0; 1770 } 1771 1772 lp->lwp_sigmask = savedmask; 1773 SIGSETNAND(lp->lwp_sigmask, waitset); 1774 /* 1775 * We won't ever be woken up. Instead, our sleep will 1776 * be broken in lwpsignal(). 1777 */ 1778 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1779 if (timeout) { 1780 if (error == ERESTART) { 1781 /* can not restart a timeout wait. */ 1782 error = EINTR; 1783 } else if (error == EAGAIN) { 1784 /* will calculate timeout by ourself. */ 1785 error = 0; 1786 } 1787 } 1788 /* Retry ... */ 1789 } 1790 1791 lp->lwp_sigmask = savedmask; 1792 if (sig) { 1793 error = 0; 1794 bzero(info, sizeof(*info)); 1795 info->si_signo = sig; 1796 spin_lock(&lp->lwp_spin); 1797 lwp_delsig(lp, sig, 1); /* take the signal! */ 1798 spin_unlock(&lp->lwp_spin); 1799 1800 if (sig == SIGKILL) { 1801 sigexit(lp, sig); 1802 /* NOT REACHED */ 1803 } 1804 } 1805 1806 return (error); 1807 } 1808 1809 /* 1810 * MPALMOSTSAFE 1811 */ 1812 int 1813 sys_sigtimedwait(struct sigtimedwait_args *uap) 1814 { 1815 struct timespec ts; 1816 struct timespec *timeout; 1817 sigset_t set; 1818 siginfo_t info; 1819 int error; 1820 1821 if (uap->timeout) { 1822 error = copyin(uap->timeout, &ts, sizeof(ts)); 1823 if (error) 1824 return (error); 1825 timeout = &ts; 1826 } else { 1827 timeout = NULL; 1828 } 1829 error = copyin(uap->set, &set, sizeof(set)); 1830 if (error) 1831 return (error); 1832 error = kern_sigtimedwait(set, &info, timeout); 1833 if (error) 1834 return (error); 1835 if (uap->info) 1836 error = copyout(&info, uap->info, sizeof(info)); 1837 /* Repost if we got an error. */ 1838 /* 1839 * XXX lwp 1840 * 1841 * This could transform a thread-specific signal to another 1842 * thread / process pending signal. 1843 */ 1844 if (error) { 1845 ksignal(curproc, info.si_signo); 1846 } else { 1847 uap->sysmsg_result = info.si_signo; 1848 } 1849 return (error); 1850 } 1851 1852 /* 1853 * MPALMOSTSAFE 1854 */ 1855 int 1856 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1857 { 1858 siginfo_t info; 1859 sigset_t set; 1860 int error; 1861 1862 error = copyin(uap->set, &set, sizeof(set)); 1863 if (error) 1864 return (error); 1865 error = kern_sigtimedwait(set, &info, NULL); 1866 if (error) 1867 return (error); 1868 if (uap->info) 1869 error = copyout(&info, uap->info, sizeof(info)); 1870 /* Repost if we got an error. */ 1871 /* 1872 * XXX lwp 1873 * 1874 * This could transform a thread-specific signal to another 1875 * thread / process pending signal. 1876 */ 1877 if (error) { 1878 ksignal(curproc, info.si_signo); 1879 } else { 1880 uap->sysmsg_result = info.si_signo; 1881 } 1882 return (error); 1883 } 1884 1885 /* 1886 * If the current process has received a signal that would interrupt a 1887 * system call, return EINTR or ERESTART as appropriate. 1888 */ 1889 int 1890 iscaught(struct lwp *lp) 1891 { 1892 struct proc *p = lp->lwp_proc; 1893 int sig; 1894 1895 if (p) { 1896 if ((sig = CURSIG(lp)) != 0) { 1897 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1898 return (EINTR); 1899 return (ERESTART); 1900 } 1901 } 1902 return(EWOULDBLOCK); 1903 } 1904 1905 /* 1906 * If the current lwp/proc has received a signal (should be caught or cause 1907 * termination, should interrupt current syscall), return the signal number. 1908 * Stop signals with default action are processed immediately, then cleared; 1909 * they aren't returned. This is checked after each entry to the system for 1910 * a syscall or trap (though this can usually be done without calling issignal 1911 * by checking the pending signal masks in the CURSIG macro). 1912 * 1913 * This routine is called via CURSIG/__cursig. We will acquire and release 1914 * p->p_token but if the caller needs to interlock the test the caller must 1915 * also hold p->p_token. 1916 * 1917 * while (sig = CURSIG(curproc)) 1918 * postsig(sig); 1919 */ 1920 int 1921 issignal(struct lwp *lp, int maytrace, int *ptokp) 1922 { 1923 struct proc *p = lp->lwp_proc; 1924 sigset_t mask; 1925 int sig, prop; 1926 int haveptok; 1927 1928 for (;;) { 1929 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1930 1931 haveptok = 0; 1932 1933 /* 1934 * If this process is supposed to stop, stop this thread. 1935 */ 1936 if (STOPLWP(p, lp)) { 1937 lwkt_gettoken(&p->p_token); 1938 tstop(); 1939 lwkt_reltoken(&p->p_token); 1940 } 1941 1942 /* 1943 * Quick check without token 1944 */ 1945 mask = lwp_sigpend(lp); 1946 SIGSETNAND(mask, lp->lwp_sigmask); 1947 if (p->p_flags & P_PPWAIT) 1948 SIG_STOPSIGMASK(mask); 1949 if (SIGISEMPTY(mask)) /* no signal to send */ 1950 return (0); 1951 1952 /* 1953 * If the signal is a member of the process signal set 1954 * we need p_token (even if it is also a member of the 1955 * lwp signal set). 1956 */ 1957 sig = sig_ffs(&mask); 1958 if (SIGISMEMBER(p->p_siglist, sig)) { 1959 /* 1960 * Recheck with token 1961 */ 1962 haveptok = 1; 1963 lwkt_gettoken(&p->p_token); 1964 1965 mask = lwp_sigpend(lp); 1966 SIGSETNAND(mask, lp->lwp_sigmask); 1967 if (p->p_flags & P_PPWAIT) 1968 SIG_STOPSIGMASK(mask); 1969 if (SIGISEMPTY(mask)) { /* no signal to send */ 1970 /* haveptok is TRUE */ 1971 lwkt_reltoken(&p->p_token); 1972 return (0); 1973 } 1974 sig = sig_ffs(&mask); 1975 } 1976 1977 STOPEVENT(p, S_SIG, sig); 1978 1979 /* 1980 * We should see pending but ignored signals 1981 * only if P_TRACED was on when they were posted. 1982 */ 1983 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1984 spin_lock(&lp->lwp_spin); 1985 lwp_delsig(lp, sig, haveptok); 1986 spin_unlock(&lp->lwp_spin); 1987 if (haveptok) 1988 lwkt_reltoken(&p->p_token); 1989 continue; 1990 } 1991 if (maytrace && 1992 (p->p_flags & P_TRACED) && 1993 (p->p_flags & P_PPWAIT) == 0) { 1994 /* 1995 * If traced, always stop, and stay stopped until 1996 * released by the parent. 1997 * 1998 * NOTE: SSTOP may get cleared during the loop, 1999 * but we do not re-notify the parent if we have 2000 * to loop several times waiting for the parent 2001 * to let us continue. 2002 * 2003 * XXX not sure if this is still true 2004 */ 2005 if (haveptok == 0) { 2006 lwkt_gettoken(&p->p_token); 2007 haveptok = 1; 2008 } 2009 p->p_xstat = sig; 2010 proc_stop(p, SSTOP); 2011 do { 2012 tstop(); 2013 } while (!trace_req(p) && (p->p_flags & P_TRACED)); 2014 2015 /* 2016 * If parent wants us to take the signal, 2017 * then it will leave it in p->p_xstat; 2018 * otherwise we just look for signals again. 2019 */ 2020 spin_lock(&lp->lwp_spin); 2021 lwp_delsig(lp, sig, 1); /* clear old signal */ 2022 spin_unlock(&lp->lwp_spin); 2023 sig = p->p_xstat; 2024 if (sig == 0) { 2025 /* haveptok is TRUE */ 2026 lwkt_reltoken(&p->p_token); 2027 continue; 2028 } 2029 2030 /* 2031 * Put the new signal into p_siglist. If the 2032 * signal is being masked, look for other signals. 2033 * 2034 * XXX lwp might need a call to ksignal() 2035 */ 2036 SIGADDSET_ATOMIC(p->p_siglist, sig); 2037 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 2038 /* haveptok is TRUE */ 2039 lwkt_reltoken(&p->p_token); 2040 continue; 2041 } 2042 2043 /* 2044 * If the traced bit got turned off, go back up 2045 * to the top to rescan signals. This ensures 2046 * that p_sig* and ps_sigact are consistent. 2047 */ 2048 if ((p->p_flags & P_TRACED) == 0) { 2049 /* haveptok is TRUE */ 2050 lwkt_reltoken(&p->p_token); 2051 continue; 2052 } 2053 } 2054 2055 /* 2056 * p_token may be held here 2057 */ 2058 prop = sigprop(sig); 2059 2060 /* 2061 * Decide whether the signal should be returned. 2062 * Return the signal's number, or fall through 2063 * to clear it from the pending mask. 2064 */ 2065 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2066 case (intptr_t)SIG_DFL: 2067 /* 2068 * Don't take default actions on system processes. 2069 */ 2070 if (p->p_pid <= 1) { 2071 #ifdef DIAGNOSTIC 2072 /* 2073 * Are you sure you want to ignore SIGSEGV 2074 * in init? XXX 2075 */ 2076 kprintf("Process (pid %lu) got signal %d\n", 2077 (u_long)p->p_pid, sig); 2078 #endif 2079 break; /* == ignore */ 2080 } 2081 2082 /* 2083 * Handle the in-kernel checkpoint action 2084 */ 2085 if (prop & SA_CKPT) { 2086 if (haveptok == 0) { 2087 lwkt_gettoken(&p->p_token); 2088 haveptok = 1; 2089 } 2090 checkpoint_signal_handler(lp); 2091 break; 2092 } 2093 2094 /* 2095 * If there is a pending stop signal to process 2096 * with default action, stop here, 2097 * then clear the signal. However, 2098 * if process is member of an orphaned 2099 * process group, ignore tty stop signals. 2100 */ 2101 if (prop & SA_STOP) { 2102 if (haveptok == 0) { 2103 lwkt_gettoken(&p->p_token); 2104 haveptok = 1; 2105 } 2106 if (p->p_flags & P_TRACED || 2107 (p->p_pgrp->pg_jobc == 0 && 2108 prop & SA_TTYSTOP)) 2109 break; /* == ignore */ 2110 if ((p->p_flags & P_WEXIT) == 0) { 2111 p->p_xstat = sig; 2112 proc_stop(p, SSTOP); 2113 tstop(); 2114 } 2115 break; 2116 } else if (prop & SA_IGNORE) { 2117 /* 2118 * Except for SIGCONT, shouldn't get here. 2119 * Default action is to ignore; drop it. 2120 */ 2121 break; /* == ignore */ 2122 } else { 2123 if (ptokp) 2124 *ptokp = haveptok; 2125 else if (haveptok) 2126 lwkt_reltoken(&p->p_token); 2127 return (sig); 2128 } 2129 2130 /*NOTREACHED*/ 2131 2132 case (intptr_t)SIG_IGN: 2133 /* 2134 * Masking above should prevent us ever trying 2135 * to take action on an ignored signal other 2136 * than SIGCONT, unless process is traced. 2137 */ 2138 if ((prop & SA_CONT) == 0 && 2139 (p->p_flags & P_TRACED) == 0) 2140 kprintf("issignal\n"); 2141 break; /* == ignore */ 2142 2143 default: 2144 /* 2145 * This signal has an action, let 2146 * postsig() process it. 2147 */ 2148 if (ptokp) 2149 *ptokp = haveptok; 2150 else if (haveptok) 2151 lwkt_reltoken(&p->p_token); 2152 return (sig); 2153 } 2154 spin_lock(&lp->lwp_spin); 2155 lwp_delsig(lp, sig, haveptok); /* take the signal! */ 2156 spin_unlock(&lp->lwp_spin); 2157 2158 if (haveptok) 2159 lwkt_reltoken(&p->p_token); 2160 } 2161 /* NOTREACHED */ 2162 } 2163 2164 /* 2165 * Take the action for the specified signal from the current set of 2166 * pending signals. 2167 * 2168 * haveptok indicates whether the caller is holding p->p_token. If the 2169 * caller is, we are responsible for releasing it. 2170 * 2171 * This routine can only be called from the top-level trap from usermode. 2172 * It is expecting to be able to modify the top-level stack frame. 2173 */ 2174 void 2175 postsig(int sig, int haveptok) 2176 { 2177 struct lwp *lp = curthread->td_lwp; 2178 struct proc *p = lp->lwp_proc; 2179 struct sigacts *ps = p->p_sigacts; 2180 sig_t action; 2181 sigset_t returnmask; 2182 int code; 2183 2184 KASSERT(sig != 0, ("postsig")); 2185 2186 /* 2187 * If we are a virtual kernel running an emulated user process 2188 * context, switch back to the virtual kernel context before 2189 * trying to post the signal. 2190 */ 2191 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2192 struct trapframe *tf = lp->lwp_md.md_regs; 2193 tf->tf_trapno = 0; 2194 vkernel_trap(lp, tf); 2195 } 2196 2197 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2198 2199 spin_lock(&lp->lwp_spin); 2200 lwp_delsig(lp, sig, haveptok); 2201 spin_unlock(&lp->lwp_spin); 2202 action = ps->ps_sigact[_SIG_IDX(sig)]; 2203 #ifdef KTRACE 2204 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2205 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2206 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2207 #endif 2208 /* 2209 * We don't need p_token after this point. 2210 */ 2211 if (haveptok) 2212 lwkt_reltoken(&p->p_token); 2213 2214 STOPEVENT(p, S_SIG, sig); 2215 2216 if (action == SIG_DFL) { 2217 /* 2218 * Default action, where the default is to kill 2219 * the process. (Other cases were ignored above.) 2220 */ 2221 sigexit(lp, sig); 2222 /* NOTREACHED */ 2223 } else { 2224 /* 2225 * If we get here, the signal must be caught. 2226 */ 2227 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2228 ("postsig action")); 2229 2230 /* 2231 * Reset the signal handler if asked to 2232 */ 2233 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2234 /* 2235 * See kern_sigaction() for origin of this code. 2236 */ 2237 SIGDELSET(p->p_sigcatch, sig); 2238 if (sig != SIGCONT && 2239 sigprop(sig) & SA_IGNORE) 2240 SIGADDSET(p->p_sigignore, sig); 2241 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2242 } 2243 2244 /* 2245 * Set the signal mask and calculate the mask to restore 2246 * when the signal function returns. 2247 * 2248 * Special case: user has done a sigsuspend. Here the 2249 * current mask is not of interest, but rather the 2250 * mask from before the sigsuspend is what we want 2251 * restored after the signal processing is completed. 2252 */ 2253 if (lp->lwp_flags & LWP_OLDMASK) { 2254 returnmask = lp->lwp_oldsigmask; 2255 lp->lwp_flags &= ~LWP_OLDMASK; 2256 } else { 2257 returnmask = lp->lwp_sigmask; 2258 } 2259 2260 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2261 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2262 SIGADDSET(lp->lwp_sigmask, sig); 2263 2264 lp->lwp_ru.ru_nsignals++; 2265 if (lp->lwp_sig != sig) { 2266 code = 0; 2267 } else { 2268 code = lp->lwp_code; 2269 lp->lwp_code = 0; 2270 lp->lwp_sig = 0; 2271 } 2272 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2273 } 2274 } 2275 2276 /* 2277 * Kill the current process for stated reason. 2278 */ 2279 void 2280 killproc(struct proc *p, char *why) 2281 { 2282 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2283 p->p_pid, p->p_comm, 2284 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2285 ksignal(p, SIGKILL); 2286 } 2287 2288 /* 2289 * Force the current process to exit with the specified signal, dumping core 2290 * if appropriate. We bypass the normal tests for masked and caught signals, 2291 * allowing unrecoverable failures to terminate the process without changing 2292 * signal state. Mark the accounting record with the signal termination. 2293 * If dumping core, save the signal number for the debugger. Calls exit and 2294 * does not return. 2295 * 2296 * This routine does not return. 2297 */ 2298 void 2299 sigexit(struct lwp *lp, int sig) 2300 { 2301 struct proc *p = lp->lwp_proc; 2302 2303 lwkt_gettoken(&p->p_token); 2304 p->p_acflag |= AXSIG; 2305 if (sigprop(sig) & SA_CORE) { 2306 lp->lwp_sig = sig; 2307 2308 /* 2309 * All threads must be stopped before we can safely coredump. 2310 * Stop threads using SCORE, which cannot be overridden. 2311 */ 2312 if (p->p_stat != SCORE) { 2313 proc_stop(p, SCORE); 2314 proc_stopwait(p); 2315 2316 if (coredump(lp, sig) == 0) 2317 sig |= WCOREFLAG; 2318 p->p_stat = SSTOP; 2319 } 2320 2321 /* 2322 * Log signals which would cause core dumps 2323 * (Log as LOG_INFO to appease those who don't want 2324 * these messages.) 2325 * XXX : Todo, as well as euid, write out ruid too 2326 */ 2327 if (kern_logsigexit) { 2328 log(LOG_INFO, 2329 "pid %d (%s), uid %d: exited on signal %d%s\n", 2330 p->p_pid, p->p_comm, 2331 p->p_ucred ? p->p_ucred->cr_uid : -1, 2332 sig &~ WCOREFLAG, 2333 sig & WCOREFLAG ? " (core dumped)" : ""); 2334 } 2335 } 2336 lwkt_reltoken(&p->p_token); 2337 exit1(W_EXITCODE(0, sig)); 2338 /* NOTREACHED */ 2339 } 2340 2341 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2342 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2343 sizeof(corefilename), "process corefile name format string"); 2344 2345 /* 2346 * expand_name(name, uid, pid) 2347 * Expand the name described in corefilename, using name, uid, and pid. 2348 * corefilename is a kprintf-like string, with three format specifiers: 2349 * %N name of process ("name") 2350 * %P process id (pid) 2351 * %U user id (uid) 2352 * For example, "%N.core" is the default; they can be disabled completely 2353 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2354 * This is controlled by the sysctl variable kern.corefile (see above). 2355 */ 2356 2357 static char * 2358 expand_name(const char *name, uid_t uid, pid_t pid) 2359 { 2360 char *temp; 2361 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2362 int i, n; 2363 char *format = corefilename; 2364 size_t namelen; 2365 2366 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2367 if (temp == NULL) 2368 return NULL; 2369 namelen = strlen(name); 2370 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2371 int l; 2372 switch (format[i]) { 2373 case '%': /* Format character */ 2374 i++; 2375 switch (format[i]) { 2376 case '%': 2377 temp[n++] = '%'; 2378 break; 2379 case 'N': /* process name */ 2380 if ((n + namelen) > MAXPATHLEN) { 2381 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2382 pid, name, uid, temp, name); 2383 kfree(temp, M_TEMP); 2384 return NULL; 2385 } 2386 memcpy(temp+n, name, namelen); 2387 n += namelen; 2388 break; 2389 case 'P': /* process id */ 2390 l = ksprintf(buf, "%u", pid); 2391 if ((n + l) > MAXPATHLEN) { 2392 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2393 pid, name, uid, temp, name); 2394 kfree(temp, M_TEMP); 2395 return NULL; 2396 } 2397 memcpy(temp+n, buf, l); 2398 n += l; 2399 break; 2400 case 'U': /* user id */ 2401 l = ksprintf(buf, "%u", uid); 2402 if ((n + l) > MAXPATHLEN) { 2403 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2404 pid, name, uid, temp, name); 2405 kfree(temp, M_TEMP); 2406 return NULL; 2407 } 2408 memcpy(temp+n, buf, l); 2409 n += l; 2410 break; 2411 default: 2412 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2413 } 2414 break; 2415 default: 2416 temp[n++] = format[i]; 2417 } 2418 } 2419 temp[n] = '\0'; 2420 return temp; 2421 } 2422 2423 /* 2424 * Dump a process' core. The main routine does some 2425 * policy checking, and creates the name of the coredump; 2426 * then it passes on a vnode and a size limit to the process-specific 2427 * coredump routine if there is one; if there _is not_ one, it returns 2428 * ENOSYS; otherwise it returns the error from the process-specific routine. 2429 * 2430 * The parameter `lp' is the lwp which triggered the coredump. 2431 */ 2432 2433 static int 2434 coredump(struct lwp *lp, int sig) 2435 { 2436 struct proc *p = lp->lwp_proc; 2437 struct vnode *vp; 2438 struct ucred *cred = p->p_ucred; 2439 struct flock lf; 2440 struct nlookupdata nd; 2441 struct vattr vattr; 2442 int error, error1; 2443 char *name; /* name of corefile */ 2444 off_t limit; 2445 2446 STOPEVENT(p, S_CORE, 0); 2447 2448 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2449 return (EFAULT); 2450 2451 /* 2452 * Note that the bulk of limit checking is done after 2453 * the corefile is created. The exception is if the limit 2454 * for corefiles is 0, in which case we don't bother 2455 * creating the corefile at all. This layout means that 2456 * a corefile is truncated instead of not being created, 2457 * if it is larger than the limit. 2458 */ 2459 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2460 if (limit == 0) 2461 return EFBIG; 2462 2463 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2464 if (name == NULL) 2465 return (EINVAL); 2466 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2467 if (error == 0) 2468 error = vn_open(&nd, NULL, 2469 O_CREAT | FWRITE | O_NOFOLLOW, 2470 S_IRUSR | S_IWUSR); 2471 kfree(name, M_TEMP); 2472 if (error) { 2473 nlookup_done(&nd); 2474 return (error); 2475 } 2476 vp = nd.nl_open_vp; 2477 nd.nl_open_vp = NULL; 2478 nlookup_done(&nd); 2479 2480 vn_unlock(vp); 2481 lf.l_whence = SEEK_SET; 2482 lf.l_start = 0; 2483 lf.l_len = 0; 2484 lf.l_type = F_WRLCK; 2485 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2486 if (error) 2487 goto out2; 2488 2489 /* Don't dump to non-regular files or files with links. */ 2490 if (vp->v_type != VREG || 2491 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2492 error = EFAULT; 2493 goto out1; 2494 } 2495 2496 /* Don't dump to files current user does not own */ 2497 if (vattr.va_uid != p->p_ucred->cr_uid) { 2498 error = EFAULT; 2499 goto out1; 2500 } 2501 2502 VATTR_NULL(&vattr); 2503 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2504 vattr.va_size = 0; 2505 VOP_SETATTR(vp, &vattr, cred); 2506 p->p_acflag |= ACORE; 2507 vn_unlock(vp); 2508 2509 error = p->p_sysent->sv_coredump ? 2510 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2511 2512 out1: 2513 lf.l_type = F_UNLCK; 2514 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2515 out2: 2516 error1 = vn_close(vp, FWRITE, NULL); 2517 if (error == 0) 2518 error = error1; 2519 return (error); 2520 } 2521 2522 /* 2523 * Nonexistent system call-- signal process (may want to handle it). 2524 * Flag error in case process won't see signal immediately (blocked or ignored). 2525 * 2526 * MPALMOSTSAFE 2527 */ 2528 /* ARGSUSED */ 2529 int 2530 sys_nosys(struct nosys_args *args) 2531 { 2532 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2533 return (EINVAL); 2534 } 2535 2536 /* 2537 * Send a SIGIO or SIGURG signal to a process or process group using 2538 * stored credentials rather than those of the current process. 2539 */ 2540 void 2541 pgsigio(struct sigio *sigio, int sig, int checkctty) 2542 { 2543 if (sigio == NULL) 2544 return; 2545 2546 if (sigio->sio_pgid > 0) { 2547 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2548 sigio->sio_proc)) 2549 ksignal(sigio->sio_proc, sig); 2550 } else if (sigio->sio_pgid < 0) { 2551 struct proc *p; 2552 struct pgrp *pg = sigio->sio_pgrp; 2553 2554 /* 2555 * Must interlock all signals against fork 2556 */ 2557 pgref(pg); 2558 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2559 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2560 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2561 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2562 ksignal(p, sig); 2563 } 2564 lockmgr(&pg->pg_lock, LK_RELEASE); 2565 pgrel(pg); 2566 } 2567 } 2568 2569 static int 2570 filt_sigattach(struct knote *kn) 2571 { 2572 struct proc *p = curproc; 2573 2574 kn->kn_ptr.p_proc = p; 2575 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2576 2577 /* XXX lock the proc here while adding to the list? */ 2578 knote_insert(&p->p_klist, kn); 2579 2580 return (0); 2581 } 2582 2583 static void 2584 filt_sigdetach(struct knote *kn) 2585 { 2586 struct proc *p = kn->kn_ptr.p_proc; 2587 2588 knote_remove(&p->p_klist, kn); 2589 } 2590 2591 /* 2592 * signal knotes are shared with proc knotes, so we apply a mask to 2593 * the hint in order to differentiate them from process hints. This 2594 * could be avoided by using a signal-specific knote list, but probably 2595 * isn't worth the trouble. 2596 */ 2597 static int 2598 filt_signal(struct knote *kn, long hint) 2599 { 2600 if (hint & NOTE_SIGNAL) { 2601 hint &= ~NOTE_SIGNAL; 2602 2603 if (kn->kn_id == hint) 2604 kn->kn_data++; 2605 } 2606 return (kn->kn_data != 0); 2607 } 2608