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 send the signal sig to process q? Only processes within 98 * the current reaper or children of the current reaper can be signaled. 99 * Normally the reaper itself cannot be signalled, unless initok is set. 100 */ 101 #define CANSIGNAL(q, sig, initok) \ 102 ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \ 103 reaper_sigtest(curproc, p, initok)) || \ 104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 105 106 /* 107 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 108 */ 109 #define CANSIGIO(ruid, uc, q) \ 110 ((uc)->cr_uid == 0 || \ 111 (ruid) == (q)->p_ucred->cr_ruid || \ 112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 113 (ruid) == (q)->p_ucred->cr_uid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_uid) 115 116 int sugid_coredump; 117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 119 120 static int do_coredump = 1; 121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 122 &do_coredump, 0, "Enable/Disable coredumps"); 123 124 /* 125 * Signal properties and actions. 126 * The array below categorizes the signals and their default actions 127 * according to the following properties: 128 */ 129 #define SA_KILL 0x01 /* terminates process by default */ 130 #define SA_CORE 0x02 /* ditto and coredumps */ 131 #define SA_STOP 0x04 /* suspend process */ 132 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 133 #define SA_IGNORE 0x10 /* ignore by default */ 134 #define SA_CONT 0x20 /* continue if suspended */ 135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 136 #define SA_CKPT 0x80 /* checkpoint process */ 137 138 139 static int sigproptbl[NSIG] = { 140 SA_KILL, /* SIGHUP */ 141 SA_KILL, /* SIGINT */ 142 SA_KILL|SA_CORE, /* SIGQUIT */ 143 SA_KILL|SA_CORE, /* SIGILL */ 144 SA_KILL|SA_CORE, /* SIGTRAP */ 145 SA_KILL|SA_CORE, /* SIGABRT */ 146 SA_KILL|SA_CORE, /* SIGEMT */ 147 SA_KILL|SA_CORE, /* SIGFPE */ 148 SA_KILL, /* SIGKILL */ 149 SA_KILL|SA_CORE, /* SIGBUS */ 150 SA_KILL|SA_CORE, /* SIGSEGV */ 151 SA_KILL|SA_CORE, /* SIGSYS */ 152 SA_KILL, /* SIGPIPE */ 153 SA_KILL, /* SIGALRM */ 154 SA_KILL, /* SIGTERM */ 155 SA_IGNORE, /* SIGURG */ 156 SA_STOP, /* SIGSTOP */ 157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 158 SA_IGNORE|SA_CONT, /* SIGCONT */ 159 SA_IGNORE, /* SIGCHLD */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 162 SA_IGNORE, /* SIGIO */ 163 SA_KILL, /* SIGXCPU */ 164 SA_KILL, /* SIGXFSZ */ 165 SA_KILL, /* SIGVTALRM */ 166 SA_KILL, /* SIGPROF */ 167 SA_IGNORE, /* SIGWINCH */ 168 SA_IGNORE, /* SIGINFO */ 169 SA_KILL, /* SIGUSR1 */ 170 SA_KILL, /* SIGUSR2 */ 171 SA_IGNORE, /* SIGTHR */ 172 SA_CKPT, /* SIGCKPT */ 173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 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 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 205 }; 206 207 static __inline int 208 sigprop(int sig) 209 { 210 211 if (sig > 0 && sig < NSIG) 212 return (sigproptbl[_SIG_IDX(sig)]); 213 return (0); 214 } 215 216 static __inline int 217 sig_ffs(sigset_t *set) 218 { 219 int i; 220 221 for (i = 0; i < _SIG_WORDS; i++) 222 if (set->__bits[i]) 223 return (ffs(set->__bits[i]) + (i * 32)); 224 return (0); 225 } 226 227 /* 228 * No requirements. 229 */ 230 int 231 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 232 { 233 struct thread *td = curthread; 234 struct proc *p = td->td_proc; 235 struct lwp *lp; 236 struct sigacts *ps = p->p_sigacts; 237 238 if (sig <= 0 || sig > _SIG_MAXSIG) 239 return (EINVAL); 240 241 lwkt_gettoken(&p->p_token); 242 243 if (oact) { 244 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 245 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 246 oact->sa_flags = 0; 247 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 248 oact->sa_flags |= SA_ONSTACK; 249 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 250 oact->sa_flags |= SA_RESTART; 251 if (SIGISMEMBER(ps->ps_sigreset, sig)) 252 oact->sa_flags |= SA_RESETHAND; 253 if (SIGISMEMBER(ps->ps_signodefer, sig)) 254 oact->sa_flags |= SA_NODEFER; 255 if (SIGISMEMBER(ps->ps_siginfo, sig)) 256 oact->sa_flags |= SA_SIGINFO; 257 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 258 oact->sa_flags |= SA_NOCLDSTOP; 259 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 260 oact->sa_flags |= SA_NOCLDWAIT; 261 } 262 if (act) { 263 /* 264 * Check for invalid requests. KILL and STOP cannot be 265 * caught. 266 */ 267 if (sig == SIGKILL || sig == SIGSTOP) { 268 if (act->sa_handler != SIG_DFL) { 269 lwkt_reltoken(&p->p_token); 270 return (EINVAL); 271 } 272 } 273 274 /* 275 * Change setting atomically. 276 */ 277 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 278 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 279 if (act->sa_flags & SA_SIGINFO) { 280 ps->ps_sigact[_SIG_IDX(sig)] = 281 (__sighandler_t *)act->sa_sigaction; 282 SIGADDSET(ps->ps_siginfo, sig); 283 } else { 284 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 285 SIGDELSET(ps->ps_siginfo, sig); 286 } 287 if (!(act->sa_flags & SA_RESTART)) 288 SIGADDSET(ps->ps_sigintr, sig); 289 else 290 SIGDELSET(ps->ps_sigintr, sig); 291 if (act->sa_flags & SA_ONSTACK) 292 SIGADDSET(ps->ps_sigonstack, sig); 293 else 294 SIGDELSET(ps->ps_sigonstack, sig); 295 if (act->sa_flags & SA_RESETHAND) 296 SIGADDSET(ps->ps_sigreset, sig); 297 else 298 SIGDELSET(ps->ps_sigreset, sig); 299 if (act->sa_flags & SA_NODEFER) 300 SIGADDSET(ps->ps_signodefer, sig); 301 else 302 SIGDELSET(ps->ps_signodefer, sig); 303 if (sig == SIGCHLD) { 304 if (act->sa_flags & SA_NOCLDSTOP) 305 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 306 else 307 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 308 if (act->sa_flags & SA_NOCLDWAIT) { 309 /* 310 * Paranoia: since SA_NOCLDWAIT is implemented 311 * by reparenting the dying child to PID 1 (and 312 * trust it to reap the zombie), PID 1 itself 313 * is forbidden to set SA_NOCLDWAIT. 314 */ 315 if (p->p_pid == 1) 316 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 317 else 318 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 319 } else { 320 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 321 } 322 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 323 ps->ps_flag |= PS_CLDSIGIGN; 324 else 325 ps->ps_flag &= ~PS_CLDSIGIGN; 326 } 327 /* 328 * Set bit in p_sigignore for signals that are set to SIG_IGN, 329 * and for signals set to SIG_DFL where the default is to 330 * ignore. However, don't put SIGCONT in p_sigignore, as we 331 * have to restart the process. 332 * 333 * Also remove the signal from the process and lwp signal 334 * list. 335 */ 336 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 337 (sigprop(sig) & SA_IGNORE && 338 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 339 SIGDELSET_ATOMIC(p->p_siglist, sig); 340 FOREACH_LWP_IN_PROC(lp, p) { 341 spin_lock(&lp->lwp_spin); 342 SIGDELSET(lp->lwp_siglist, sig); 343 spin_unlock(&lp->lwp_spin); 344 } 345 if (sig != SIGCONT) { 346 /* easier in ksignal */ 347 SIGADDSET(p->p_sigignore, sig); 348 } 349 SIGDELSET(p->p_sigcatch, sig); 350 } else { 351 SIGDELSET(p->p_sigignore, sig); 352 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 353 SIGDELSET(p->p_sigcatch, sig); 354 else 355 SIGADDSET(p->p_sigcatch, sig); 356 } 357 } 358 lwkt_reltoken(&p->p_token); 359 return (0); 360 } 361 362 int 363 sys_sigaction(struct sigaction_args *uap) 364 { 365 struct sigaction act, oact; 366 struct sigaction *actp, *oactp; 367 int error; 368 369 actp = (uap->act != NULL) ? &act : NULL; 370 oactp = (uap->oact != NULL) ? &oact : NULL; 371 if (actp) { 372 error = copyin(uap->act, actp, sizeof(act)); 373 if (error) 374 return (error); 375 } 376 error = kern_sigaction(uap->sig, actp, oactp); 377 if (oactp && !error) { 378 error = copyout(oactp, uap->oact, sizeof(oact)); 379 } 380 return (error); 381 } 382 383 /* 384 * Initialize signal state for process 0; 385 * set to ignore signals that are ignored by default. 386 */ 387 void 388 siginit(struct proc *p) 389 { 390 int i; 391 392 for (i = 1; i <= NSIG; i++) 393 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 394 SIGADDSET(p->p_sigignore, i); 395 } 396 397 /* 398 * Reset signals for an exec of the specified process. 399 */ 400 void 401 execsigs(struct proc *p) 402 { 403 struct sigacts *ps = p->p_sigacts; 404 struct lwp *lp; 405 int sig; 406 407 lp = ONLY_LWP_IN_PROC(p); 408 409 /* 410 * Reset caught signals. Held signals remain held 411 * through p_sigmask (unless they were caught, 412 * and are now ignored by default). 413 */ 414 while (SIGNOTEMPTY(p->p_sigcatch)) { 415 sig = sig_ffs(&p->p_sigcatch); 416 SIGDELSET(p->p_sigcatch, sig); 417 if (sigprop(sig) & SA_IGNORE) { 418 if (sig != SIGCONT) 419 SIGADDSET(p->p_sigignore, sig); 420 SIGDELSET_ATOMIC(p->p_siglist, sig); 421 /* don't need spinlock */ 422 SIGDELSET(lp->lwp_siglist, sig); 423 } 424 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 425 } 426 427 /* 428 * Reset stack state to the user stack. 429 * Clear set of signals caught on the signal stack. 430 */ 431 lp->lwp_sigstk.ss_flags = SS_DISABLE; 432 lp->lwp_sigstk.ss_size = 0; 433 lp->lwp_sigstk.ss_sp = NULL; 434 lp->lwp_flags &= ~LWP_ALTSTACK; 435 /* 436 * Reset no zombies if child dies flag as Solaris does. 437 */ 438 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 439 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 440 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 441 } 442 443 /* 444 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 445 * 446 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 447 * p == curproc. 448 */ 449 int 450 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 451 { 452 struct thread *td = curthread; 453 struct lwp *lp = td->td_lwp; 454 struct proc *p = td->td_proc; 455 int error; 456 457 lwkt_gettoken(&p->p_token); 458 459 if (oset != NULL) 460 *oset = lp->lwp_sigmask; 461 462 error = 0; 463 if (set != NULL) { 464 switch (how) { 465 case SIG_BLOCK: 466 SIG_CANTMASK(*set); 467 SIGSETOR(lp->lwp_sigmask, *set); 468 break; 469 case SIG_UNBLOCK: 470 SIGSETNAND(lp->lwp_sigmask, *set); 471 break; 472 case SIG_SETMASK: 473 SIG_CANTMASK(*set); 474 lp->lwp_sigmask = *set; 475 break; 476 default: 477 error = EINVAL; 478 break; 479 } 480 } 481 482 lwkt_reltoken(&p->p_token); 483 484 return (error); 485 } 486 487 /* 488 * sigprocmask() 489 * 490 * MPSAFE 491 */ 492 int 493 sys_sigprocmask(struct sigprocmask_args *uap) 494 { 495 sigset_t set, oset; 496 sigset_t *setp, *osetp; 497 int error; 498 499 setp = (uap->set != NULL) ? &set : NULL; 500 osetp = (uap->oset != NULL) ? &oset : NULL; 501 if (setp) { 502 error = copyin(uap->set, setp, sizeof(set)); 503 if (error) 504 return (error); 505 } 506 error = kern_sigprocmask(uap->how, setp, osetp); 507 if (osetp && !error) { 508 error = copyout(osetp, uap->oset, sizeof(oset)); 509 } 510 return (error); 511 } 512 513 /* 514 * MPSAFE 515 */ 516 int 517 kern_sigpending(struct __sigset *set) 518 { 519 struct lwp *lp = curthread->td_lwp; 520 521 *set = lwp_sigpend(lp); 522 523 return (0); 524 } 525 526 /* 527 * MPSAFE 528 */ 529 int 530 sys_sigpending(struct sigpending_args *uap) 531 { 532 sigset_t set; 533 int error; 534 535 error = kern_sigpending(&set); 536 537 if (error == 0) 538 error = copyout(&set, uap->set, sizeof(set)); 539 return (error); 540 } 541 542 /* 543 * Suspend process until signal, providing mask to be set 544 * in the meantime. 545 * 546 * MPSAFE 547 */ 548 int 549 kern_sigsuspend(struct __sigset *set) 550 { 551 struct thread *td = curthread; 552 struct lwp *lp = td->td_lwp; 553 struct proc *p = td->td_proc; 554 struct sigacts *ps = p->p_sigacts; 555 556 /* 557 * When returning from sigsuspend, we want 558 * the old mask to be restored after the 559 * signal handler has finished. Thus, we 560 * save it here and mark the sigacts structure 561 * to indicate this. 562 */ 563 lp->lwp_oldsigmask = lp->lwp_sigmask; 564 lp->lwp_flags |= LWP_OLDMASK; 565 566 SIG_CANTMASK(*set); 567 lp->lwp_sigmask = *set; 568 while (tsleep(ps, PCATCH, "pause", 0) == 0) 569 /* void */; 570 /* always return EINTR rather than ERESTART... */ 571 return (EINTR); 572 } 573 574 /* 575 * Note nonstandard calling convention: libc stub passes mask, not 576 * pointer, to save a copyin. 577 * 578 * MPSAFE 579 */ 580 int 581 sys_sigsuspend(struct sigsuspend_args *uap) 582 { 583 sigset_t mask; 584 int error; 585 586 error = copyin(uap->sigmask, &mask, sizeof(mask)); 587 if (error) 588 return (error); 589 590 error = kern_sigsuspend(&mask); 591 592 return (error); 593 } 594 595 /* 596 * MPSAFE 597 */ 598 int 599 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 600 { 601 struct thread *td = curthread; 602 struct lwp *lp = td->td_lwp; 603 struct proc *p = td->td_proc; 604 605 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 606 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 607 608 if (oss) 609 *oss = lp->lwp_sigstk; 610 611 if (ss) { 612 if (ss->ss_flags & ~SS_DISABLE) 613 return (EINVAL); 614 if (ss->ss_flags & SS_DISABLE) { 615 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 616 return (EPERM); 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, uap->oss ? &oss : NULL); 646 647 if (error == 0 && uap->oss) 648 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 649 return (error); 650 } 651 652 /* 653 * Common code for kill process group/broadcast kill. 654 * cp is calling process. 655 */ 656 struct killpg_info { 657 int nfound; 658 int sig; 659 }; 660 661 static int killpg_all_callback(struct proc *p, void *data); 662 663 static int 664 dokillpg(int sig, int pgid, int all) 665 { 666 struct killpg_info info; 667 struct proc *cp = curproc; 668 struct proc *p; 669 struct pgrp *pgrp; 670 671 info.nfound = 0; 672 info.sig = sig; 673 674 if (all) { 675 /* 676 * broadcast 677 */ 678 allproc_scan(killpg_all_callback, &info, 0); 679 } else { 680 if (pgid == 0) { 681 /* 682 * zero pgid means send to my process group. 683 */ 684 pgrp = cp->p_pgrp; 685 pgref(pgrp); 686 } else { 687 pgrp = pgfind(pgid); 688 if (pgrp == NULL) 689 return (ESRCH); 690 } 691 692 /* 693 * Must interlock all signals against fork 694 */ 695 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 696 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 697 if (p->p_pid <= 1 || 698 p->p_stat == SZOMB || 699 (p->p_flags & P_SYSTEM) || 700 !CANSIGNAL(p, sig, 0)) { 701 continue; 702 } 703 ++info.nfound; 704 if (sig) 705 ksignal(p, sig); 706 } 707 lockmgr(&pgrp->pg_lock, LK_RELEASE); 708 pgrel(pgrp); 709 } 710 return (info.nfound ? 0 : ESRCH); 711 } 712 713 static int 714 killpg_all_callback(struct proc *p, void *data) 715 { 716 struct killpg_info *info = data; 717 718 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 719 p == curproc || !CANSIGNAL(p, info->sig, 0)) { 720 return (0); 721 } 722 ++info->nfound; 723 if (info->sig) 724 ksignal(p, info->sig); 725 return(0); 726 } 727 728 /* 729 * Send a general signal to a process or LWPs within that process. 730 * 731 * Note that new signals cannot be sent if a process is exiting or already 732 * a zombie, but we return success anyway as userland is likely to not handle 733 * the race properly. 734 * 735 * No requirements. 736 */ 737 int 738 kern_kill(int sig, pid_t pid, lwpid_t tid) 739 { 740 int t; 741 742 if ((u_int)sig > _SIG_MAXSIG) 743 return (EINVAL); 744 745 if (pid > 0) { 746 struct proc *p; 747 struct lwp *lp = NULL; 748 749 /* 750 * Send a signal to a single process. If the kill() is 751 * racing an exiting process which has not yet been reaped 752 * act as though the signal was delivered successfully but 753 * don't actually try to deliver the signal. 754 */ 755 if ((p = pfind(pid)) == NULL) { 756 if ((p = zpfind(pid)) == NULL) 757 return (ESRCH); 758 PRELE(p); 759 return (0); 760 } 761 if (p != curproc) { 762 lwkt_gettoken_shared(&p->p_token); 763 if (!CANSIGNAL(p, sig, 1)) { 764 lwkt_reltoken(&p->p_token); 765 PRELE(p); 766 return (EPERM); 767 } 768 lwkt_reltoken(&p->p_token); 769 } 770 771 /* 772 * NOP if the process is exiting. Note that lwpsignal() is 773 * called directly with P_WEXIT set to kill individual LWPs 774 * during exit, which is allowed. 775 */ 776 if (p->p_flags & P_WEXIT) { 777 PRELE(p); 778 return (0); 779 } 780 if (tid != -1) { 781 lwkt_gettoken_shared(&p->p_token); 782 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 783 if (lp == NULL) { 784 lwkt_reltoken(&p->p_token); 785 PRELE(p); 786 return (ESRCH); 787 } 788 LWPHOLD(lp); 789 lwkt_reltoken(&p->p_token); 790 } 791 if (sig) 792 lwpsignal(p, lp, sig); 793 if (lp) 794 LWPRELE(lp); 795 PRELE(p); 796 797 return (0); 798 } 799 800 /* 801 * If we come here, pid is a special broadcast pid. 802 * This doesn't mix with a tid. 803 */ 804 if (tid != -1) 805 return (EINVAL); 806 807 switch (pid) { 808 case -1: /* broadcast signal */ 809 t = (dokillpg(sig, 0, 1)); 810 break; 811 case 0: /* signal own process group */ 812 t = (dokillpg(sig, 0, 0)); 813 break; 814 default: /* negative explicit process group */ 815 t = (dokillpg(sig, -pid, 0)); 816 break; 817 } 818 return t; 819 } 820 821 int 822 sys_kill(struct kill_args *uap) 823 { 824 int error; 825 826 error = kern_kill(uap->signum, uap->pid, -1); 827 return (error); 828 } 829 830 int 831 sys_lwp_kill(struct lwp_kill_args *uap) 832 { 833 int error; 834 pid_t pid = uap->pid; 835 836 /* 837 * A tid is mandatory for lwp_kill(), otherwise 838 * you could simply use kill(). 839 */ 840 if (uap->tid == -1) 841 return (EINVAL); 842 843 /* 844 * To save on a getpid() function call for intra-process 845 * signals, pid == -1 means current process. 846 */ 847 if (pid == -1) 848 pid = curproc->p_pid; 849 850 error = kern_kill(uap->signum, pid, uap->tid); 851 return (error); 852 } 853 854 /* 855 * Send a signal to a process group. 856 */ 857 void 858 gsignal(int pgid, int sig) 859 { 860 struct pgrp *pgrp; 861 862 if (pgid && (pgrp = pgfind(pgid))) 863 pgsignal(pgrp, sig, 0); 864 } 865 866 /* 867 * Send a signal to a process group. If checktty is 1, 868 * limit to members which have a controlling terminal. 869 * 870 * pg_lock interlocks against a fork that might be in progress, to 871 * ensure that the new child process picks up the signal. 872 */ 873 void 874 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 875 { 876 struct proc *p; 877 878 /* 879 * Must interlock all signals against fork 880 */ 881 if (pgrp) { 882 pgref(pgrp); 883 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 884 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 885 if (checkctty == 0 || p->p_flags & P_CONTROLT) 886 ksignal(p, sig); 887 } 888 lockmgr(&pgrp->pg_lock, LK_RELEASE); 889 pgrel(pgrp); 890 } 891 } 892 893 /* 894 * Send a signal caused by a trap to the current lwp. If it will be caught 895 * immediately, deliver it with correct code. Otherwise, post it normally. 896 * 897 * These signals may ONLY be delivered to the specified lwp and may never 898 * be delivered to the process generically. 899 */ 900 void 901 trapsignal(struct lwp *lp, int sig, u_long code) 902 { 903 struct proc *p = lp->lwp_proc; 904 struct sigacts *ps = p->p_sigacts; 905 906 /* 907 * If we are a virtual kernel running an emulated user process 908 * context, switch back to the virtual kernel context before 909 * trying to post the signal. 910 */ 911 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 912 struct trapframe *tf = lp->lwp_md.md_regs; 913 tf->tf_trapno = 0; 914 vkernel_trap(lp, tf); 915 } 916 917 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 918 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 919 lp->lwp_ru.ru_nsignals++; 920 #ifdef KTRACE 921 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 922 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 923 &lp->lwp_sigmask, code); 924 #endif 925 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 926 &lp->lwp_sigmask, code); 927 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 928 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 929 SIGADDSET(lp->lwp_sigmask, sig); 930 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 931 /* 932 * See kern_sigaction() for origin of this code. 933 */ 934 SIGDELSET(p->p_sigcatch, sig); 935 if (sig != SIGCONT && 936 sigprop(sig) & SA_IGNORE) 937 SIGADDSET(p->p_sigignore, sig); 938 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 939 } 940 } else { 941 lp->lwp_code = code; /* XXX for core dump/debugger */ 942 lp->lwp_sig = sig; /* XXX to verify code */ 943 lwpsignal(p, lp, sig); 944 } 945 } 946 947 /* 948 * Find a suitable lwp to deliver the signal to. Returns NULL if all 949 * lwps hold the signal blocked. 950 * 951 * Caller must hold p->p_token. 952 * 953 * Returns a lp or NULL. If non-NULL the lp is held and its token is 954 * acquired. 955 */ 956 static struct lwp * 957 find_lwp_for_signal(struct proc *p, int sig) 958 { 959 struct lwp *lp; 960 struct lwp *run, *sleep, *stop; 961 962 /* 963 * If the running/preempted thread belongs to the proc to which 964 * the signal is being delivered and this thread does not block 965 * the signal, then we can avoid a context switch by delivering 966 * the signal to this thread, because it will return to userland 967 * soon anyways. 968 */ 969 lp = lwkt_preempted_proc(); 970 if (lp != NULL && lp->lwp_proc == p) { 971 LWPHOLD(lp); 972 lwkt_gettoken(&lp->lwp_token); 973 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 974 /* return w/ token held */ 975 return (lp); 976 } 977 lwkt_reltoken(&lp->lwp_token); 978 LWPRELE(lp); 979 } 980 981 run = sleep = stop = NULL; 982 FOREACH_LWP_IN_PROC(lp, p) { 983 /* 984 * If the signal is being blocked by the lwp, then this 985 * lwp is not eligible for receiving the signal. 986 */ 987 LWPHOLD(lp); 988 lwkt_gettoken(&lp->lwp_token); 989 990 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 991 lwkt_reltoken(&lp->lwp_token); 992 LWPRELE(lp); 993 continue; 994 } 995 996 switch (lp->lwp_stat) { 997 case LSRUN: 998 if (sleep) { 999 lwkt_token_swap(); 1000 lwkt_reltoken(&sleep->lwp_token); 1001 LWPRELE(sleep); 1002 sleep = NULL; 1003 run = lp; 1004 } else if (stop) { 1005 lwkt_token_swap(); 1006 lwkt_reltoken(&stop->lwp_token); 1007 LWPRELE(stop); 1008 stop = NULL; 1009 run = lp; 1010 } else { 1011 run = lp; 1012 } 1013 break; 1014 case LSSLEEP: 1015 if (lp->lwp_flags & LWP_SINTR) { 1016 if (sleep) { 1017 lwkt_reltoken(&lp->lwp_token); 1018 LWPRELE(lp); 1019 } else if (stop) { 1020 lwkt_token_swap(); 1021 lwkt_reltoken(&stop->lwp_token); 1022 LWPRELE(stop); 1023 stop = NULL; 1024 sleep = lp; 1025 } else { 1026 sleep = lp; 1027 } 1028 } else { 1029 lwkt_reltoken(&lp->lwp_token); 1030 LWPRELE(lp); 1031 } 1032 break; 1033 case LSSTOP: 1034 if (sleep) { 1035 lwkt_reltoken(&lp->lwp_token); 1036 LWPRELE(lp); 1037 } else if (stop) { 1038 lwkt_reltoken(&lp->lwp_token); 1039 LWPRELE(lp); 1040 } else { 1041 stop = lp; 1042 } 1043 break; 1044 } 1045 if (run) 1046 break; 1047 } 1048 1049 if (run != NULL) 1050 return (run); 1051 else if (sleep != NULL) 1052 return (sleep); 1053 else 1054 return (stop); 1055 } 1056 1057 /* 1058 * Send the signal to the process. If the signal has an action, the action 1059 * is usually performed by the target process rather than the caller; we add 1060 * the signal to the set of pending signals for the process. 1061 * 1062 * Exceptions: 1063 * o When a stop signal is sent to a sleeping process that takes the 1064 * default action, the process is stopped without awakening it. 1065 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1066 * regardless of the signal action (eg, blocked or ignored). 1067 * 1068 * Other ignored signals are discarded immediately. 1069 * 1070 * If the caller wishes to call this function from a hard code section the 1071 * caller must already hold p->p_token (see kern_clock.c). 1072 * 1073 * No requirements. 1074 */ 1075 void 1076 ksignal(struct proc *p, int sig) 1077 { 1078 lwpsignal(p, NULL, sig); 1079 } 1080 1081 /* 1082 * The core for ksignal. lp may be NULL, then a suitable thread 1083 * will be chosen. If not, lp MUST be a member of p. 1084 * 1085 * If the caller wishes to call this function from a hard code section the 1086 * caller must already hold p->p_token. 1087 * 1088 * No requirements. 1089 */ 1090 void 1091 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1092 { 1093 struct proc *q; 1094 sig_t action; 1095 int prop; 1096 1097 if (sig > _SIG_MAXSIG || sig <= 0) { 1098 kprintf("lwpsignal: signal %d\n", sig); 1099 panic("lwpsignal signal number"); 1100 } 1101 1102 KKASSERT(lp == NULL || lp->lwp_proc == p); 1103 1104 /* 1105 * We don't want to race... well, all sorts of things. Get appropriate 1106 * tokens. 1107 * 1108 * Don't try to deliver a generic signal to an exiting process, 1109 * the signal structures could be in flux. We check the LWP later 1110 * on. 1111 */ 1112 PHOLD(p); 1113 if (lp) { 1114 LWPHOLD(lp); 1115 lwkt_gettoken(&lp->lwp_token); 1116 } else { 1117 lwkt_gettoken(&p->p_token); 1118 if (p->p_flags & P_WEXIT) 1119 goto out; 1120 } 1121 1122 prop = sigprop(sig); 1123 1124 /* 1125 * If proc is traced, always give parent a chance; 1126 * if signal event is tracked by procfs, give *that* 1127 * a chance, as well. 1128 */ 1129 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1130 action = SIG_DFL; 1131 } else { 1132 /* 1133 * Do not try to deliver signals to an exiting lwp other 1134 * than SIGKILL. Note that we must still deliver the signal 1135 * if P_WEXIT is set in the process flags. 1136 */ 1137 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { 1138 lwkt_reltoken(&lp->lwp_token); 1139 LWPRELE(lp); 1140 PRELE(p); 1141 return; 1142 } 1143 1144 /* 1145 * If the signal is being ignored, then we forget about 1146 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1147 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1148 */ 1149 if (SIGISMEMBER(p->p_sigignore, sig)) { 1150 /* 1151 * Even if a signal is set SIG_IGN, it may still be 1152 * lurking in a kqueue. 1153 */ 1154 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1155 if (lp) { 1156 lwkt_reltoken(&lp->lwp_token); 1157 LWPRELE(lp); 1158 } else { 1159 lwkt_reltoken(&p->p_token); 1160 } 1161 PRELE(p); 1162 return; 1163 } 1164 if (SIGISMEMBER(p->p_sigcatch, sig)) 1165 action = SIG_CATCH; 1166 else 1167 action = SIG_DFL; 1168 } 1169 1170 /* 1171 * If continuing, clear any pending STOP signals for the whole 1172 * process. 1173 */ 1174 if (prop & SA_CONT) { 1175 lwkt_gettoken(&p->p_token); 1176 SIG_STOPSIGMASK_ATOMIC(p->p_siglist); 1177 lwkt_reltoken(&p->p_token); 1178 } 1179 1180 if (prop & SA_STOP) { 1181 /* 1182 * If sending a tty stop signal to a member of an orphaned 1183 * process group, discard the signal here if the action 1184 * is default; don't stop the process below if sleeping, 1185 * and don't clear any pending SIGCONT. 1186 */ 1187 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && 1188 action == SIG_DFL) { 1189 if (lp) { 1190 lwkt_reltoken(&lp->lwp_token); 1191 LWPRELE(lp); 1192 } else { 1193 lwkt_reltoken(&p->p_token); 1194 } 1195 PRELE(p); 1196 return; 1197 } 1198 lwkt_gettoken(&p->p_token); 1199 SIG_CONTSIGMASK_ATOMIC(p->p_siglist); 1200 p->p_flags &= ~P_CONTINUED; 1201 lwkt_reltoken(&p->p_token); 1202 } 1203 1204 if (p->p_stat == SSTOP) { 1205 /* 1206 * Nobody can handle this signal, add it to the lwp or 1207 * process pending list 1208 */ 1209 lwkt_gettoken(&p->p_token); 1210 if (p->p_stat != SSTOP) { 1211 lwkt_reltoken(&p->p_token); 1212 goto not_stopped; 1213 } 1214 if (lp) { 1215 spin_lock(&lp->lwp_spin); 1216 SIGADDSET(lp->lwp_siglist, sig); 1217 spin_unlock(&lp->lwp_spin); 1218 } else { 1219 SIGADDSET_ATOMIC(p->p_siglist, sig); 1220 } 1221 1222 /* 1223 * If the process is stopped and is being traced, then no 1224 * further action is necessary. 1225 */ 1226 if (p->p_flags & P_TRACED) { 1227 lwkt_reltoken(&p->p_token); 1228 goto out; 1229 } 1230 1231 /* 1232 * If the process is stopped and receives a KILL signal, 1233 * make the process runnable. 1234 */ 1235 if (sig == SIGKILL) { 1236 proc_unstop(p, SSTOP); 1237 lwkt_reltoken(&p->p_token); 1238 goto active_process; 1239 } 1240 1241 /* 1242 * If the process is stopped and receives a CONT signal, 1243 * then try to make the process runnable again. 1244 */ 1245 if (prop & SA_CONT) { 1246 /* 1247 * If SIGCONT is default (or ignored), we continue the 1248 * process but don't leave the signal in p_siglist, as 1249 * it has no further action. If SIGCONT is held, we 1250 * continue the process and leave the signal in 1251 * p_siglist. If the process catches SIGCONT, let it 1252 * handle the signal itself. 1253 * 1254 * XXX what if the signal is being held blocked? 1255 * 1256 * Token required to interlock kern_wait(). 1257 * Reparenting can also cause a race so we have to 1258 * hold (q). 1259 */ 1260 q = p->p_pptr; 1261 PHOLD(q); 1262 lwkt_gettoken(&q->p_token); 1263 p->p_flags |= P_CONTINUED; 1264 wakeup(q); 1265 if (action == SIG_DFL) 1266 SIGDELSET_ATOMIC(p->p_siglist, sig); 1267 proc_unstop(p, SSTOP); 1268 lwkt_reltoken(&q->p_token); 1269 PRELE(q); 1270 lwkt_reltoken(&p->p_token); 1271 if (action == SIG_CATCH) 1272 goto active_process; 1273 goto out; 1274 } 1275 1276 /* 1277 * If the process is stopped and receives another STOP 1278 * signal, we do not need to stop it again. If we did 1279 * the shell could get confused. 1280 * 1281 * However, if the current/preempted lwp is part of the 1282 * process receiving the signal, we need to keep it, 1283 * so that this lwp can stop in issignal() later, as 1284 * we don't want to wait until it reaches userret! 1285 */ 1286 if (prop & SA_STOP) { 1287 if (lwkt_preempted_proc() == NULL || 1288 lwkt_preempted_proc()->lwp_proc != p) { 1289 SIGDELSET_ATOMIC(p->p_siglist, sig); 1290 } 1291 } 1292 1293 /* 1294 * Otherwise the process is stopped and it received some 1295 * signal, which does not change its stopped state. When 1296 * the process is continued a wakeup(p) will be issued which 1297 * will wakeup any threads sleeping in tstop(). 1298 */ 1299 lwkt_reltoken(&p->p_token); 1300 goto out; 1301 /* NOTREACHED */ 1302 } 1303 not_stopped: 1304 ; 1305 /* else not stopped */ 1306 active_process: 1307 1308 /* 1309 * Never deliver a lwp-specific signal to a random lwp. 1310 */ 1311 if (lp == NULL) { 1312 /* NOTE: returns lp w/ token held */ 1313 lp = find_lwp_for_signal(p, sig); 1314 if (lp) { 1315 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1316 lwkt_reltoken(&lp->lwp_token); 1317 LWPRELE(lp); 1318 lp = NULL; 1319 /* maintain proc token */ 1320 } else { 1321 lwkt_token_swap(); 1322 lwkt_reltoken(&p->p_token); 1323 /* maintain lp token */ 1324 } 1325 } 1326 } 1327 1328 /* 1329 * Deliver to the process generically if (1) the signal is being 1330 * sent to any thread or (2) we could not find a thread to deliver 1331 * it to. 1332 */ 1333 if (lp == NULL) { 1334 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1335 SIGADDSET_ATOMIC(p->p_siglist, sig); 1336 goto out; 1337 } 1338 1339 /* 1340 * Deliver to a specific LWP whether it masks it or not. It will 1341 * not be dispatched if masked but we must still deliver it. 1342 */ 1343 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1344 (p->p_flags & P_TRACED) == 0) { 1345 lwkt_gettoken(&p->p_token); 1346 p->p_nice = NZERO; 1347 lwkt_reltoken(&p->p_token); 1348 } 1349 1350 /* 1351 * If the process receives a STOP signal which indeed needs to 1352 * stop the process, do so. If the process chose to catch the 1353 * signal, it will be treated like any other signal. 1354 */ 1355 if ((prop & SA_STOP) && action == SIG_DFL) { 1356 /* 1357 * If a child holding parent blocked, stopping 1358 * could cause deadlock. Take no action at this 1359 * time. 1360 */ 1361 lwkt_gettoken(&p->p_token); 1362 if (p->p_flags & P_PPWAIT) { 1363 SIGADDSET_ATOMIC(p->p_siglist, sig); 1364 lwkt_reltoken(&p->p_token); 1365 goto out; 1366 } 1367 1368 /* 1369 * Do not actually try to manipulate the process, but simply 1370 * stop it. Lwps will stop as soon as they safely can. 1371 * 1372 * Ignore stop if the process is exiting. 1373 */ 1374 if ((p->p_flags & P_WEXIT) == 0) { 1375 p->p_xstat = sig; 1376 proc_stop(p, SSTOP); 1377 } 1378 lwkt_reltoken(&p->p_token); 1379 goto out; 1380 } 1381 1382 /* 1383 * If it is a CONT signal with default action, just ignore it. 1384 */ 1385 if ((prop & SA_CONT) && action == SIG_DFL) 1386 goto out; 1387 1388 /* 1389 * Mark signal pending at this specific thread. 1390 */ 1391 spin_lock(&lp->lwp_spin); 1392 SIGADDSET(lp->lwp_siglist, sig); 1393 spin_unlock(&lp->lwp_spin); 1394 1395 lwp_signotify(lp); 1396 1397 out: 1398 if (lp) { 1399 lwkt_reltoken(&lp->lwp_token); 1400 LWPRELE(lp); 1401 } else { 1402 lwkt_reltoken(&p->p_token); 1403 } 1404 PRELE(p); 1405 } 1406 1407 /* 1408 * Notify the LWP that a signal has arrived. The LWP does not have to be 1409 * sleeping on the current cpu. 1410 * 1411 * p->p_token and lp->lwp_token must be held on call. 1412 * 1413 * We can only safely schedule the thread on its current cpu and only if 1414 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1415 * the correct cpu we are properly interlocked, otherwise we could be 1416 * racing other thread transition states (or the lwp is on the user scheduler 1417 * runq but not scheduled) and must not do anything. 1418 * 1419 * Since we hold the lwp token we know the lwp cannot be ripped out from 1420 * under us so we can safely hold it to prevent it from being ripped out 1421 * from under us if we are forced to IPI another cpu to make the local 1422 * checks there. 1423 * 1424 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1425 * which we won't in an IPI so any fixups have to be done here, effectively 1426 * replicating part of what setrunnable() does. 1427 */ 1428 static void 1429 lwp_signotify(struct lwp *lp) 1430 { 1431 thread_t dtd; 1432 1433 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1434 dtd = lp->lwp_thread; 1435 1436 crit_enter(); 1437 if (lp == lwkt_preempted_proc()) { 1438 /* 1439 * lwp is on the current cpu AND it is currently running 1440 * (we preempted it). 1441 */ 1442 signotify(); 1443 } else if (lp->lwp_flags & LWP_SINTR) { 1444 /* 1445 * lwp is sitting in tsleep() with PCATCH set 1446 */ 1447 if (dtd->td_gd == mycpu) { 1448 setrunnable(lp); 1449 } else { 1450 /* 1451 * We can only adjust lwp_stat while we hold the 1452 * lwp_token, and we won't in the IPI function. 1453 */ 1454 LWPHOLD(lp); 1455 if (lp->lwp_stat == LSSTOP) 1456 lp->lwp_stat = LSSLEEP; 1457 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1458 } 1459 } else if (dtd->td_flags & TDF_SINTR) { 1460 /* 1461 * lwp is sitting in lwkt_sleep() with PCATCH set. 1462 */ 1463 if (dtd->td_gd == mycpu) { 1464 setrunnable(lp); 1465 } else { 1466 /* 1467 * We can only adjust lwp_stat while we hold the 1468 * lwp_token, and we won't in the IPI function. 1469 */ 1470 LWPHOLD(lp); 1471 if (lp->lwp_stat == LSSTOP) 1472 lp->lwp_stat = LSSLEEP; 1473 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1474 } 1475 } else { 1476 /* 1477 * Otherwise the lwp is either in some uninterruptible state 1478 * or it is on the userland scheduler's runqueue waiting to 1479 * be scheduled to a cpu, or it is running in userland. We 1480 * generally want to send an IPI so a running target gets the 1481 * signal ASAP, otherwise a scheduler-tick worth of latency 1482 * will occur. 1483 * 1484 * Issue an IPI to the remote cpu to knock it into the kernel, 1485 * remote cpu will issue the cpu-local signotify() if the IPI 1486 * preempts the desired thread. 1487 */ 1488 if (dtd->td_gd != mycpu) { 1489 LWPHOLD(lp); 1490 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1491 } 1492 } 1493 crit_exit(); 1494 } 1495 1496 /* 1497 * This function is called via an IPI so we cannot call setrunnable() here 1498 * (because while we hold the lp we don't own its token, and can't get it 1499 * from an IPI). 1500 * 1501 * We are interlocked by virtue of being on the same cpu as the target. If 1502 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1503 * the target thread. 1504 */ 1505 static void 1506 lwp_signotify_remote(void *arg) 1507 { 1508 struct lwp *lp = arg; 1509 thread_t td = lp->lwp_thread; 1510 1511 if (lp == lwkt_preempted_proc()) { 1512 signotify(); 1513 LWPRELE(lp); 1514 } else if (td->td_gd == mycpu) { 1515 if ((lp->lwp_flags & LWP_SINTR) || 1516 (td->td_flags & TDF_SINTR)) { 1517 lwkt_schedule(td); 1518 } 1519 LWPRELE(lp); 1520 } else { 1521 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1522 /* LWPHOLD() is forwarded to the target cpu */ 1523 } 1524 } 1525 1526 /* 1527 * Caller must hold p->p_token 1528 */ 1529 void 1530 proc_stop(struct proc *p, int sig) 1531 { 1532 struct proc *q; 1533 struct lwp *lp; 1534 1535 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1536 1537 /* 1538 * If somebody raced us, be happy with it. SCORE overrides SSTOP. 1539 */ 1540 if (sig == SCORE) { 1541 if (p->p_stat == SCORE || p->p_stat == SZOMB) 1542 return; 1543 } else { 1544 if (p->p_stat == SSTOP || p->p_stat == SCORE || 1545 p->p_stat == SZOMB) { 1546 return; 1547 } 1548 } 1549 p->p_stat = sig; 1550 1551 FOREACH_LWP_IN_PROC(lp, p) { 1552 LWPHOLD(lp); 1553 lwkt_gettoken(&lp->lwp_token); 1554 1555 switch (lp->lwp_stat) { 1556 case LSSTOP: 1557 /* 1558 * Do nothing, we are already counted in 1559 * p_nstopped. 1560 */ 1561 break; 1562 1563 case LSSLEEP: 1564 /* 1565 * We're sleeping, but we will stop before 1566 * returning to userspace, so count us 1567 * as stopped as well. We set LWP_MP_WSTOP 1568 * to signal the lwp that it should not 1569 * increase p_nstopped when reaching tstop(). 1570 * 1571 * LWP_MP_WSTOP is protected by lp->lwp_token. 1572 */ 1573 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1574 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1575 ++p->p_nstopped; 1576 } 1577 break; 1578 1579 case LSRUN: 1580 /* 1581 * We might notify ourself, but that's not 1582 * a problem. 1583 */ 1584 lwp_signotify(lp); 1585 break; 1586 } 1587 lwkt_reltoken(&lp->lwp_token); 1588 LWPRELE(lp); 1589 } 1590 1591 if (p->p_nstopped == p->p_nthreads) { 1592 /* 1593 * Token required to interlock kern_wait(). Reparenting can 1594 * also cause a race so we have to hold (q). 1595 */ 1596 q = p->p_pptr; 1597 PHOLD(q); 1598 lwkt_gettoken(&q->p_token); 1599 p->p_flags &= ~P_WAITED; 1600 wakeup(q); 1601 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1602 ksignal(p->p_pptr, SIGCHLD); 1603 lwkt_reltoken(&q->p_token); 1604 PRELE(q); 1605 } 1606 } 1607 1608 /* 1609 * Caller must hold p_token 1610 */ 1611 void 1612 proc_unstop(struct proc *p, int sig) 1613 { 1614 struct lwp *lp; 1615 1616 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1617 1618 if (p->p_stat != sig) 1619 return; 1620 1621 p->p_stat = SACTIVE; 1622 1623 FOREACH_LWP_IN_PROC(lp, p) { 1624 LWPHOLD(lp); 1625 lwkt_gettoken(&lp->lwp_token); 1626 1627 switch (lp->lwp_stat) { 1628 case LSRUN: 1629 /* 1630 * Uh? Not stopped? Well, I guess that's okay. 1631 */ 1632 if (bootverbose) 1633 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1634 p->p_pid, lp->lwp_tid); 1635 break; 1636 1637 case LSSLEEP: 1638 /* 1639 * Still sleeping. Don't bother waking it up. 1640 * However, if this thread was counted as 1641 * stopped, undo this. 1642 * 1643 * Nevertheless we call setrunnable() so that it 1644 * will wake up in case a signal or timeout arrived 1645 * in the meantime. 1646 * 1647 * LWP_MP_WSTOP is protected by lp->lwp_token. 1648 */ 1649 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1650 atomic_clear_int(&lp->lwp_mpflags, 1651 LWP_MP_WSTOP); 1652 --p->p_nstopped; 1653 } else { 1654 if (bootverbose) 1655 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1656 p->p_pid, lp->lwp_tid); 1657 } 1658 /* FALLTHROUGH */ 1659 1660 case LSSTOP: 1661 /* 1662 * This handles any lwp's waiting in a tsleep with 1663 * SIGCATCH. 1664 */ 1665 lwp_signotify(lp); 1666 break; 1667 1668 } 1669 lwkt_reltoken(&lp->lwp_token); 1670 LWPRELE(lp); 1671 } 1672 1673 /* 1674 * This handles any lwp's waiting in tstop(). We have interlocked 1675 * the setting of p_stat by acquiring and releasing each lpw's 1676 * token. 1677 */ 1678 wakeup(p); 1679 } 1680 1681 /* 1682 * Wait for all threads except the current thread to stop. 1683 */ 1684 static void 1685 proc_stopwait(struct proc *p) 1686 { 1687 while ((p->p_stat == SSTOP || p->p_stat == SCORE) && 1688 p->p_nstopped < p->p_nthreads - 1) { 1689 tsleep_interlock(&p->p_nstopped, 0); 1690 if (p->p_nstopped < p->p_nthreads - 1) { 1691 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); 1692 } 1693 } 1694 } 1695 1696 /* 1697 * No requirements. 1698 */ 1699 static int 1700 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1701 { 1702 sigset_t savedmask, set; 1703 struct proc *p = curproc; 1704 struct lwp *lp = curthread->td_lwp; 1705 int error, sig, hz, timevalid = 0; 1706 struct timespec rts, ets, ts; 1707 struct timeval tv; 1708 1709 error = 0; 1710 sig = 0; 1711 ets.tv_sec = 0; /* silence compiler warning */ 1712 ets.tv_nsec = 0; /* silence compiler warning */ 1713 SIG_CANTMASK(waitset); 1714 savedmask = lp->lwp_sigmask; 1715 1716 if (timeout) { 1717 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1718 timeout->tv_nsec < 1000000000) { 1719 timevalid = 1; 1720 getnanouptime(&rts); 1721 ets = rts; 1722 timespecadd(&ets, timeout); 1723 } 1724 } 1725 1726 for (;;) { 1727 set = lwp_sigpend(lp); 1728 SIGSETAND(set, waitset); 1729 if ((sig = sig_ffs(&set)) != 0) { 1730 SIGFILLSET(lp->lwp_sigmask); 1731 SIGDELSET(lp->lwp_sigmask, sig); 1732 SIG_CANTMASK(lp->lwp_sigmask); 1733 sig = issignal(lp, 1, 0); 1734 /* 1735 * It may be a STOP signal, in the case, issignal 1736 * returns 0, because we may stop there, and new 1737 * signal can come in, we should restart if we got 1738 * nothing. 1739 */ 1740 if (sig == 0) 1741 continue; 1742 else 1743 break; 1744 } 1745 1746 /* 1747 * Previous checking got nothing, and we retried but still 1748 * got nothing, we should return the error status. 1749 */ 1750 if (error) 1751 break; 1752 1753 /* 1754 * POSIX says this must be checked after looking for pending 1755 * signals. 1756 */ 1757 if (timeout) { 1758 if (timevalid == 0) { 1759 error = EINVAL; 1760 break; 1761 } 1762 getnanouptime(&rts); 1763 if (timespeccmp(&rts, &ets, >=)) { 1764 error = EAGAIN; 1765 break; 1766 } 1767 ts = ets; 1768 timespecsub(&ts, &rts); 1769 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1770 hz = tvtohz_high(&tv); 1771 } else { 1772 hz = 0; 1773 } 1774 1775 lp->lwp_sigmask = savedmask; 1776 SIGSETNAND(lp->lwp_sigmask, waitset); 1777 /* 1778 * We won't ever be woken up. Instead, our sleep will 1779 * be broken in lwpsignal(). 1780 */ 1781 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1782 if (timeout) { 1783 if (error == ERESTART) { 1784 /* can not restart a timeout wait. */ 1785 error = EINTR; 1786 } else if (error == EAGAIN) { 1787 /* will calculate timeout by ourself. */ 1788 error = 0; 1789 } 1790 } 1791 /* Retry ... */ 1792 } 1793 1794 lp->lwp_sigmask = savedmask; 1795 if (sig) { 1796 error = 0; 1797 bzero(info, sizeof(*info)); 1798 info->si_signo = sig; 1799 spin_lock(&lp->lwp_spin); 1800 lwp_delsig(lp, sig, 1); /* take the signal! */ 1801 spin_unlock(&lp->lwp_spin); 1802 1803 if (sig == SIGKILL) { 1804 sigexit(lp, sig); 1805 /* NOT REACHED */ 1806 } 1807 } 1808 1809 return (error); 1810 } 1811 1812 /* 1813 * MPALMOSTSAFE 1814 */ 1815 int 1816 sys_sigtimedwait(struct sigtimedwait_args *uap) 1817 { 1818 struct timespec ts; 1819 struct timespec *timeout; 1820 sigset_t set; 1821 siginfo_t info; 1822 int error; 1823 1824 if (uap->timeout) { 1825 error = copyin(uap->timeout, &ts, sizeof(ts)); 1826 if (error) 1827 return (error); 1828 timeout = &ts; 1829 } else { 1830 timeout = NULL; 1831 } 1832 error = copyin(uap->set, &set, sizeof(set)); 1833 if (error) 1834 return (error); 1835 error = kern_sigtimedwait(set, &info, timeout); 1836 if (error) 1837 return (error); 1838 if (uap->info) 1839 error = copyout(&info, uap->info, sizeof(info)); 1840 /* Repost if we got an error. */ 1841 /* 1842 * XXX lwp 1843 * 1844 * This could transform a thread-specific signal to another 1845 * thread / process pending signal. 1846 */ 1847 if (error) { 1848 ksignal(curproc, info.si_signo); 1849 } else { 1850 uap->sysmsg_result = info.si_signo; 1851 } 1852 return (error); 1853 } 1854 1855 /* 1856 * MPALMOSTSAFE 1857 */ 1858 int 1859 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1860 { 1861 siginfo_t info; 1862 sigset_t set; 1863 int error; 1864 1865 error = copyin(uap->set, &set, sizeof(set)); 1866 if (error) 1867 return (error); 1868 error = kern_sigtimedwait(set, &info, NULL); 1869 if (error) 1870 return (error); 1871 if (uap->info) 1872 error = copyout(&info, uap->info, sizeof(info)); 1873 /* Repost if we got an error. */ 1874 /* 1875 * XXX lwp 1876 * 1877 * This could transform a thread-specific signal to another 1878 * thread / process pending signal. 1879 */ 1880 if (error) { 1881 ksignal(curproc, info.si_signo); 1882 } else { 1883 uap->sysmsg_result = info.si_signo; 1884 } 1885 return (error); 1886 } 1887 1888 /* 1889 * If the current process has received a signal that would interrupt a 1890 * system call, return EINTR or ERESTART as appropriate. 1891 */ 1892 int 1893 iscaught(struct lwp *lp) 1894 { 1895 struct proc *p = lp->lwp_proc; 1896 int sig; 1897 1898 if (p) { 1899 if ((sig = CURSIG(lp)) != 0) { 1900 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1901 return (EINTR); 1902 return (ERESTART); 1903 } 1904 } 1905 return(EWOULDBLOCK); 1906 } 1907 1908 /* 1909 * If the current lwp/proc has received a signal (should be caught or cause 1910 * termination, should interrupt current syscall), return the signal number. 1911 * Stop signals with default action are processed immediately, then cleared; 1912 * they aren't returned. This is checked after each entry to the system for 1913 * a syscall or trap (though this can usually be done without calling issignal 1914 * by checking the pending signal masks in the CURSIG macro). 1915 * 1916 * This routine is called via CURSIG/__cursig. We will acquire and release 1917 * p->p_token but if the caller needs to interlock the test the caller must 1918 * also hold p->p_token. 1919 * 1920 * while (sig = CURSIG(curproc)) 1921 * postsig(sig); 1922 */ 1923 int 1924 issignal(struct lwp *lp, int maytrace, int *ptokp) 1925 { 1926 struct proc *p = lp->lwp_proc; 1927 sigset_t mask; 1928 int sig, prop; 1929 int haveptok; 1930 1931 for (;;) { 1932 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1933 1934 haveptok = 0; 1935 1936 /* 1937 * If this process is supposed to stop, stop this thread. 1938 */ 1939 if (STOPLWP(p, lp)) { 1940 lwkt_gettoken(&p->p_token); 1941 tstop(); 1942 lwkt_reltoken(&p->p_token); 1943 } 1944 1945 /* 1946 * Quick check without token 1947 */ 1948 mask = lwp_sigpend(lp); 1949 SIGSETNAND(mask, lp->lwp_sigmask); 1950 if (p->p_flags & P_PPWAIT) 1951 SIG_STOPSIGMASK(mask); 1952 if (SIGISEMPTY(mask)) /* no signal to send */ 1953 return (0); 1954 1955 /* 1956 * If the signal is a member of the process signal set 1957 * we need p_token (even if it is also a member of the 1958 * lwp signal set). 1959 */ 1960 sig = sig_ffs(&mask); 1961 if (SIGISMEMBER(p->p_siglist, sig)) { 1962 /* 1963 * Recheck with token 1964 */ 1965 haveptok = 1; 1966 lwkt_gettoken(&p->p_token); 1967 1968 mask = lwp_sigpend(lp); 1969 SIGSETNAND(mask, lp->lwp_sigmask); 1970 if (p->p_flags & P_PPWAIT) 1971 SIG_STOPSIGMASK(mask); 1972 if (SIGISEMPTY(mask)) { /* no signal to send */ 1973 /* haveptok is TRUE */ 1974 lwkt_reltoken(&p->p_token); 1975 return (0); 1976 } 1977 sig = sig_ffs(&mask); 1978 } 1979 1980 STOPEVENT(p, S_SIG, sig); 1981 1982 /* 1983 * We should see pending but ignored signals 1984 * only if P_TRACED was on when they were posted. 1985 */ 1986 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1987 spin_lock(&lp->lwp_spin); 1988 lwp_delsig(lp, sig, haveptok); 1989 spin_unlock(&lp->lwp_spin); 1990 if (haveptok) 1991 lwkt_reltoken(&p->p_token); 1992 continue; 1993 } 1994 if (maytrace && 1995 (p->p_flags & P_TRACED) && 1996 (p->p_flags & P_PPWAIT) == 0) { 1997 /* 1998 * If traced, always stop, and stay stopped until 1999 * released by the parent. 2000 * 2001 * NOTE: SSTOP may get cleared during the loop, 2002 * but we do not re-notify the parent if we have 2003 * to loop several times waiting for the parent 2004 * to let us continue. 2005 * 2006 * XXX not sure if this is still true 2007 */ 2008 if (haveptok == 0) { 2009 lwkt_gettoken(&p->p_token); 2010 haveptok = 1; 2011 } 2012 p->p_xstat = sig; 2013 proc_stop(p, SSTOP); 2014 do { 2015 tstop(); 2016 } while (!trace_req(p) && (p->p_flags & P_TRACED)); 2017 2018 /* 2019 * If parent wants us to take the signal, 2020 * then it will leave it in p->p_xstat; 2021 * otherwise we just look for signals again. 2022 */ 2023 spin_lock(&lp->lwp_spin); 2024 lwp_delsig(lp, sig, 1); /* clear old signal */ 2025 spin_unlock(&lp->lwp_spin); 2026 sig = p->p_xstat; 2027 if (sig == 0) { 2028 /* haveptok is TRUE */ 2029 lwkt_reltoken(&p->p_token); 2030 continue; 2031 } 2032 2033 /* 2034 * Put the new signal into p_siglist. If the 2035 * signal is being masked, look for other signals. 2036 * 2037 * XXX lwp might need a call to ksignal() 2038 */ 2039 SIGADDSET_ATOMIC(p->p_siglist, sig); 2040 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 2041 /* haveptok is TRUE */ 2042 lwkt_reltoken(&p->p_token); 2043 continue; 2044 } 2045 2046 /* 2047 * If the traced bit got turned off, go back up 2048 * to the top to rescan signals. This ensures 2049 * that p_sig* and ps_sigact are consistent. 2050 */ 2051 if ((p->p_flags & P_TRACED) == 0) { 2052 /* haveptok is TRUE */ 2053 lwkt_reltoken(&p->p_token); 2054 continue; 2055 } 2056 } 2057 2058 /* 2059 * p_token may be held here 2060 */ 2061 prop = sigprop(sig); 2062 2063 /* 2064 * Decide whether the signal should be returned. 2065 * Return the signal's number, or fall through 2066 * to clear it from the pending mask. 2067 */ 2068 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2069 case (intptr_t)SIG_DFL: 2070 /* 2071 * Don't take default actions on system processes. 2072 */ 2073 if (p->p_pid <= 1) { 2074 #ifdef DIAGNOSTIC 2075 /* 2076 * Are you sure you want to ignore SIGSEGV 2077 * in init? XXX 2078 */ 2079 kprintf("Process (pid %lu) got signal %d\n", 2080 (u_long)p->p_pid, sig); 2081 #endif 2082 break; /* == ignore */ 2083 } 2084 2085 /* 2086 * Handle the in-kernel checkpoint action 2087 */ 2088 if (prop & SA_CKPT) { 2089 if (haveptok == 0) { 2090 lwkt_gettoken(&p->p_token); 2091 haveptok = 1; 2092 } 2093 checkpoint_signal_handler(lp); 2094 break; 2095 } 2096 2097 /* 2098 * If there is a pending stop signal to process 2099 * with default action, stop here, 2100 * then clear the signal. However, 2101 * if process is member of an orphaned 2102 * process group, ignore tty stop signals. 2103 */ 2104 if (prop & SA_STOP) { 2105 if (haveptok == 0) { 2106 lwkt_gettoken(&p->p_token); 2107 haveptok = 1; 2108 } 2109 if (p->p_flags & P_TRACED || 2110 (p->p_pgrp->pg_jobc == 0 && 2111 prop & SA_TTYSTOP)) 2112 break; /* == ignore */ 2113 if ((p->p_flags & P_WEXIT) == 0) { 2114 p->p_xstat = sig; 2115 proc_stop(p, SSTOP); 2116 tstop(); 2117 } 2118 break; 2119 } else if (prop & SA_IGNORE) { 2120 /* 2121 * Except for SIGCONT, shouldn't get here. 2122 * Default action is to ignore; drop it. 2123 */ 2124 break; /* == ignore */ 2125 } else { 2126 if (ptokp) 2127 *ptokp = haveptok; 2128 else if (haveptok) 2129 lwkt_reltoken(&p->p_token); 2130 return (sig); 2131 } 2132 2133 /*NOTREACHED*/ 2134 2135 case (intptr_t)SIG_IGN: 2136 /* 2137 * Masking above should prevent us ever trying 2138 * to take action on an ignored signal other 2139 * than SIGCONT, unless process is traced. 2140 */ 2141 if ((prop & SA_CONT) == 0 && 2142 (p->p_flags & P_TRACED) == 0) 2143 kprintf("issignal\n"); 2144 break; /* == ignore */ 2145 2146 default: 2147 /* 2148 * This signal has an action, let 2149 * postsig() process it. 2150 */ 2151 if (ptokp) 2152 *ptokp = haveptok; 2153 else if (haveptok) 2154 lwkt_reltoken(&p->p_token); 2155 return (sig); 2156 } 2157 spin_lock(&lp->lwp_spin); 2158 lwp_delsig(lp, sig, haveptok); /* take the signal! */ 2159 spin_unlock(&lp->lwp_spin); 2160 2161 if (haveptok) 2162 lwkt_reltoken(&p->p_token); 2163 } 2164 /* NOTREACHED */ 2165 } 2166 2167 /* 2168 * Take the action for the specified signal from the current set of 2169 * pending signals. 2170 * 2171 * haveptok indicates whether the caller is holding p->p_token. If the 2172 * caller is, we are responsible for releasing it. 2173 * 2174 * This routine can only be called from the top-level trap from usermode. 2175 * It is expecting to be able to modify the top-level stack frame. 2176 */ 2177 void 2178 postsig(int sig, int haveptok) 2179 { 2180 struct lwp *lp = curthread->td_lwp; 2181 struct proc *p = lp->lwp_proc; 2182 struct sigacts *ps = p->p_sigacts; 2183 sig_t action; 2184 sigset_t returnmask; 2185 int code; 2186 2187 KASSERT(sig != 0, ("postsig")); 2188 2189 /* 2190 * If we are a virtual kernel running an emulated user process 2191 * context, switch back to the virtual kernel context before 2192 * trying to post the signal. 2193 */ 2194 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2195 struct trapframe *tf = lp->lwp_md.md_regs; 2196 tf->tf_trapno = 0; 2197 vkernel_trap(lp, tf); 2198 } 2199 2200 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2201 2202 spin_lock(&lp->lwp_spin); 2203 lwp_delsig(lp, sig, haveptok); 2204 spin_unlock(&lp->lwp_spin); 2205 action = ps->ps_sigact[_SIG_IDX(sig)]; 2206 #ifdef KTRACE 2207 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2208 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2209 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2210 #endif 2211 /* 2212 * We don't need p_token after this point. 2213 */ 2214 if (haveptok) 2215 lwkt_reltoken(&p->p_token); 2216 2217 STOPEVENT(p, S_SIG, sig); 2218 2219 if (action == SIG_DFL) { 2220 /* 2221 * Default action, where the default is to kill 2222 * the process. (Other cases were ignored above.) 2223 */ 2224 sigexit(lp, sig); 2225 /* NOTREACHED */ 2226 } else { 2227 /* 2228 * If we get here, the signal must be caught. 2229 */ 2230 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2231 ("postsig action")); 2232 2233 /* 2234 * Reset the signal handler if asked to 2235 */ 2236 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2237 /* 2238 * See kern_sigaction() for origin of this code. 2239 */ 2240 SIGDELSET(p->p_sigcatch, sig); 2241 if (sig != SIGCONT && 2242 sigprop(sig) & SA_IGNORE) 2243 SIGADDSET(p->p_sigignore, sig); 2244 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2245 } 2246 2247 /* 2248 * Set the signal mask and calculate the mask to restore 2249 * when the signal function returns. 2250 * 2251 * Special case: user has done a sigsuspend. Here the 2252 * current mask is not of interest, but rather the 2253 * mask from before the sigsuspend is what we want 2254 * restored after the signal processing is completed. 2255 */ 2256 if (lp->lwp_flags & LWP_OLDMASK) { 2257 returnmask = lp->lwp_oldsigmask; 2258 lp->lwp_flags &= ~LWP_OLDMASK; 2259 } else { 2260 returnmask = lp->lwp_sigmask; 2261 } 2262 2263 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2264 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2265 SIGADDSET(lp->lwp_sigmask, sig); 2266 2267 lp->lwp_ru.ru_nsignals++; 2268 if (lp->lwp_sig != sig) { 2269 code = 0; 2270 } else { 2271 code = lp->lwp_code; 2272 lp->lwp_code = 0; 2273 lp->lwp_sig = 0; 2274 } 2275 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2276 } 2277 } 2278 2279 /* 2280 * Kill the current process for stated reason. 2281 */ 2282 void 2283 killproc(struct proc *p, char *why) 2284 { 2285 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2286 p->p_pid, p->p_comm, 2287 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2288 ksignal(p, SIGKILL); 2289 } 2290 2291 /* 2292 * Force the current process to exit with the specified signal, dumping core 2293 * if appropriate. We bypass the normal tests for masked and caught signals, 2294 * allowing unrecoverable failures to terminate the process without changing 2295 * signal state. Mark the accounting record with the signal termination. 2296 * If dumping core, save the signal number for the debugger. Calls exit and 2297 * does not return. 2298 * 2299 * This routine does not return. 2300 */ 2301 void 2302 sigexit(struct lwp *lp, int sig) 2303 { 2304 struct proc *p = lp->lwp_proc; 2305 2306 lwkt_gettoken(&p->p_token); 2307 p->p_acflag |= AXSIG; 2308 if (sigprop(sig) & SA_CORE) { 2309 lp->lwp_sig = sig; 2310 2311 /* 2312 * All threads must be stopped before we can safely coredump. 2313 * Stop threads using SCORE, which cannot be overridden. 2314 */ 2315 if (p->p_stat != SCORE) { 2316 proc_stop(p, SCORE); 2317 proc_stopwait(p); 2318 2319 if (coredump(lp, sig) == 0) 2320 sig |= WCOREFLAG; 2321 p->p_stat = SSTOP; 2322 } 2323 2324 /* 2325 * Log signals which would cause core dumps 2326 * (Log as LOG_INFO to appease those who don't want 2327 * these messages.) 2328 * XXX : Todo, as well as euid, write out ruid too 2329 */ 2330 if (kern_logsigexit) { 2331 log(LOG_INFO, 2332 "pid %d (%s), uid %d: exited on signal %d%s\n", 2333 p->p_pid, p->p_comm, 2334 p->p_ucred ? p->p_ucred->cr_uid : -1, 2335 sig &~ WCOREFLAG, 2336 sig & WCOREFLAG ? " (core dumped)" : ""); 2337 } 2338 } 2339 lwkt_reltoken(&p->p_token); 2340 exit1(W_EXITCODE(0, sig)); 2341 /* NOTREACHED */ 2342 } 2343 2344 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2345 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2346 sizeof(corefilename), "process corefile name format string"); 2347 2348 /* 2349 * expand_name(name, uid, pid) 2350 * Expand the name described in corefilename, using name, uid, and pid. 2351 * corefilename is a kprintf-like string, with three format specifiers: 2352 * %N name of process ("name") 2353 * %P process id (pid) 2354 * %U user id (uid) 2355 * For example, "%N.core" is the default; they can be disabled completely 2356 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2357 * This is controlled by the sysctl variable kern.corefile (see above). 2358 */ 2359 2360 static char * 2361 expand_name(const char *name, uid_t uid, pid_t pid) 2362 { 2363 char *temp; 2364 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2365 int i, n; 2366 char *format = corefilename; 2367 size_t namelen; 2368 2369 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2370 if (temp == NULL) 2371 return NULL; 2372 namelen = strlen(name); 2373 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2374 int l; 2375 switch (format[i]) { 2376 case '%': /* Format character */ 2377 i++; 2378 switch (format[i]) { 2379 case '%': 2380 temp[n++] = '%'; 2381 break; 2382 case 'N': /* process name */ 2383 if ((n + namelen) > MAXPATHLEN) { 2384 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2385 pid, name, uid, temp, name); 2386 kfree(temp, M_TEMP); 2387 return NULL; 2388 } 2389 memcpy(temp+n, name, namelen); 2390 n += namelen; 2391 break; 2392 case 'P': /* process id */ 2393 l = ksprintf(buf, "%u", pid); 2394 if ((n + l) > MAXPATHLEN) { 2395 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2396 pid, name, uid, temp, name); 2397 kfree(temp, M_TEMP); 2398 return NULL; 2399 } 2400 memcpy(temp+n, buf, l); 2401 n += l; 2402 break; 2403 case 'U': /* user id */ 2404 l = ksprintf(buf, "%u", uid); 2405 if ((n + l) > MAXPATHLEN) { 2406 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2407 pid, name, uid, temp, name); 2408 kfree(temp, M_TEMP); 2409 return NULL; 2410 } 2411 memcpy(temp+n, buf, l); 2412 n += l; 2413 break; 2414 default: 2415 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2416 } 2417 break; 2418 default: 2419 temp[n++] = format[i]; 2420 } 2421 } 2422 temp[n] = '\0'; 2423 return temp; 2424 } 2425 2426 /* 2427 * Dump a process' core. The main routine does some 2428 * policy checking, and creates the name of the coredump; 2429 * then it passes on a vnode and a size limit to the process-specific 2430 * coredump routine if there is one; if there _is not_ one, it returns 2431 * ENOSYS; otherwise it returns the error from the process-specific routine. 2432 * 2433 * The parameter `lp' is the lwp which triggered the coredump. 2434 */ 2435 2436 static int 2437 coredump(struct lwp *lp, int sig) 2438 { 2439 struct proc *p = lp->lwp_proc; 2440 struct vnode *vp; 2441 struct ucred *cred = p->p_ucred; 2442 struct flock lf; 2443 struct nlookupdata nd; 2444 struct vattr vattr; 2445 int error, error1; 2446 char *name; /* name of corefile */ 2447 off_t limit; 2448 2449 STOPEVENT(p, S_CORE, 0); 2450 2451 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2452 return (EFAULT); 2453 2454 /* 2455 * Note that the bulk of limit checking is done after 2456 * the corefile is created. The exception is if the limit 2457 * for corefiles is 0, in which case we don't bother 2458 * creating the corefile at all. This layout means that 2459 * a corefile is truncated instead of not being created, 2460 * if it is larger than the limit. 2461 */ 2462 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2463 if (limit == 0) 2464 return EFBIG; 2465 2466 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2467 if (name == NULL) 2468 return (EINVAL); 2469 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2470 if (error == 0) 2471 error = vn_open(&nd, NULL, 2472 O_CREAT | FWRITE | O_NOFOLLOW, 2473 S_IRUSR | S_IWUSR); 2474 kfree(name, M_TEMP); 2475 if (error) { 2476 nlookup_done(&nd); 2477 return (error); 2478 } 2479 vp = nd.nl_open_vp; 2480 nd.nl_open_vp = NULL; 2481 nlookup_done(&nd); 2482 2483 vn_unlock(vp); 2484 lf.l_whence = SEEK_SET; 2485 lf.l_start = 0; 2486 lf.l_len = 0; 2487 lf.l_type = F_WRLCK; 2488 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2489 if (error) 2490 goto out2; 2491 2492 /* Don't dump to non-regular files or files with links. */ 2493 if (vp->v_type != VREG || 2494 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2495 error = EFAULT; 2496 goto out1; 2497 } 2498 2499 /* Don't dump to files current user does not own */ 2500 if (vattr.va_uid != p->p_ucred->cr_uid) { 2501 error = EFAULT; 2502 goto out1; 2503 } 2504 2505 VATTR_NULL(&vattr); 2506 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2507 vattr.va_size = 0; 2508 VOP_SETATTR(vp, &vattr, cred); 2509 p->p_acflag |= ACORE; 2510 vn_unlock(vp); 2511 2512 error = p->p_sysent->sv_coredump ? 2513 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2514 2515 out1: 2516 lf.l_type = F_UNLCK; 2517 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2518 out2: 2519 error1 = vn_close(vp, FWRITE, NULL); 2520 if (error == 0) 2521 error = error1; 2522 return (error); 2523 } 2524 2525 /* 2526 * Nonexistent system call-- signal process (may want to handle it). 2527 * Flag error in case process won't see signal immediately (blocked or ignored). 2528 * 2529 * MPALMOSTSAFE 2530 */ 2531 /* ARGSUSED */ 2532 int 2533 sys_nosys(struct nosys_args *args) 2534 { 2535 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2536 return (EINVAL); 2537 } 2538 2539 /* 2540 * Send a SIGIO or SIGURG signal to a process or process group using 2541 * stored credentials rather than those of the current process. 2542 */ 2543 void 2544 pgsigio(struct sigio *sigio, int sig, int checkctty) 2545 { 2546 if (sigio == NULL) 2547 return; 2548 2549 if (sigio->sio_pgid > 0) { 2550 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2551 sigio->sio_proc)) 2552 ksignal(sigio->sio_proc, sig); 2553 } else if (sigio->sio_pgid < 0) { 2554 struct proc *p; 2555 struct pgrp *pg = sigio->sio_pgrp; 2556 2557 /* 2558 * Must interlock all signals against fork 2559 */ 2560 pgref(pg); 2561 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2562 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2563 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2564 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2565 ksignal(p, sig); 2566 } 2567 lockmgr(&pg->pg_lock, LK_RELEASE); 2568 pgrel(pg); 2569 } 2570 } 2571 2572 static int 2573 filt_sigattach(struct knote *kn) 2574 { 2575 struct proc *p = curproc; 2576 2577 kn->kn_ptr.p_proc = p; 2578 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2579 2580 /* XXX lock the proc here while adding to the list? */ 2581 knote_insert(&p->p_klist, kn); 2582 2583 return (0); 2584 } 2585 2586 static void 2587 filt_sigdetach(struct knote *kn) 2588 { 2589 struct proc *p = kn->kn_ptr.p_proc; 2590 2591 knote_remove(&p->p_klist, kn); 2592 } 2593 2594 /* 2595 * signal knotes are shared with proc knotes, so we apply a mask to 2596 * the hint in order to differentiate them from process hints. This 2597 * could be avoided by using a signal-specific knote list, but probably 2598 * isn't worth the trouble. 2599 */ 2600 static int 2601 filt_signal(struct knote *kn, long hint) 2602 { 2603 if (hint & NOTE_SIGNAL) { 2604 hint &= ~NOTE_SIGNAL; 2605 2606 if (kn->kn_id == hint) 2607 kn->kn_data++; 2608 } 2609 return (kn->kn_data != 0); 2610 } 2611