1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/sysproto.h> 48 #include <sys/signalvar.h> 49 #include <sys/resourcevar.h> 50 #include <sys/vnode.h> 51 #include <sys/event.h> 52 #include <sys/proc.h> 53 #include <sys/nlookup.h> 54 #include <sys/pioctl.h> 55 #include <sys/systm.h> 56 #include <sys/acct.h> 57 #include <sys/fcntl.h> 58 #include <sys/lock.h> 59 #include <sys/wait.h> 60 #include <sys/ktrace.h> 61 #include <sys/syslog.h> 62 #include <sys/stat.h> 63 #include <sys/sysent.h> 64 #include <sys/sysctl.h> 65 #include <sys/malloc.h> 66 #include <sys/interrupt.h> 67 #include <sys/unistd.h> 68 #include <sys/kern_syscall.h> 69 #include <sys/vkernel.h> 70 71 #include <sys/signal2.h> 72 #include <sys/thread2.h> 73 74 #include <machine/cpu.h> 75 #include <machine/smp.h> 76 77 static int coredump(struct lwp *, int); 78 static char *expand_name(const char *, uid_t, pid_t); 79 static int dokillpg(int sig, int pgid, int all); 80 static int sig_ffs(sigset_t *set); 81 static int sigprop(int sig); 82 static void lwp_signotify(struct lwp *lp); 83 #ifdef SMP 84 static void signotify_remote(void *arg); 85 #endif 86 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 87 struct timespec *timeout); 88 89 static int filt_sigattach(struct knote *kn); 90 static void filt_sigdetach(struct knote *kn); 91 static int filt_signal(struct knote *kn, long hint); 92 93 struct filterops sig_filtops = 94 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 95 96 static int kern_logsigexit = 1; 97 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 98 &kern_logsigexit, 0, 99 "Log processes quitting on abnormal signals to syslog(3)"); 100 101 /* 102 * Can process p, with pcred pc, send the signal sig to process q? 103 */ 104 #define CANSIGNAL(q, sig) \ 105 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 106 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 107 108 /* 109 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 110 */ 111 #define CANSIGIO(ruid, uc, q) \ 112 ((uc)->cr_uid == 0 || \ 113 (ruid) == (q)->p_ucred->cr_ruid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 115 (ruid) == (q)->p_ucred->cr_uid || \ 116 (uc)->cr_uid == (q)->p_ucred->cr_uid) 117 118 int sugid_coredump; 119 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 120 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 121 122 static int do_coredump = 1; 123 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 124 &do_coredump, 0, "Enable/Disable coredumps"); 125 126 /* 127 * Signal properties and actions. 128 * The array below categorizes the signals and their default actions 129 * according to the following properties: 130 */ 131 #define SA_KILL 0x01 /* terminates process by default */ 132 #define SA_CORE 0x02 /* ditto and coredumps */ 133 #define SA_STOP 0x04 /* suspend process */ 134 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 135 #define SA_IGNORE 0x10 /* ignore by default */ 136 #define SA_CONT 0x20 /* continue if suspended */ 137 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 138 #define SA_CKPT 0x80 /* checkpoint process */ 139 140 141 static int sigproptbl[NSIG] = { 142 SA_KILL, /* SIGHUP */ 143 SA_KILL, /* SIGINT */ 144 SA_KILL|SA_CORE, /* SIGQUIT */ 145 SA_KILL|SA_CORE, /* SIGILL */ 146 SA_KILL|SA_CORE, /* SIGTRAP */ 147 SA_KILL|SA_CORE, /* SIGABRT */ 148 SA_KILL|SA_CORE, /* SIGEMT */ 149 SA_KILL|SA_CORE, /* SIGFPE */ 150 SA_KILL, /* SIGKILL */ 151 SA_KILL|SA_CORE, /* SIGBUS */ 152 SA_KILL|SA_CORE, /* SIGSEGV */ 153 SA_KILL|SA_CORE, /* SIGSYS */ 154 SA_KILL, /* SIGPIPE */ 155 SA_KILL, /* SIGALRM */ 156 SA_KILL, /* SIGTERM */ 157 SA_IGNORE, /* SIGURG */ 158 SA_STOP, /* SIGSTOP */ 159 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 160 SA_IGNORE|SA_CONT, /* SIGCONT */ 161 SA_IGNORE, /* SIGCHLD */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 163 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 164 SA_IGNORE, /* SIGIO */ 165 SA_KILL, /* SIGXCPU */ 166 SA_KILL, /* SIGXFSZ */ 167 SA_KILL, /* SIGVTALRM */ 168 SA_KILL, /* SIGPROF */ 169 SA_IGNORE, /* SIGWINCH */ 170 SA_IGNORE, /* SIGINFO */ 171 SA_KILL, /* SIGUSR1 */ 172 SA_KILL, /* SIGUSR2 */ 173 SA_IGNORE, /* SIGTHR */ 174 SA_CKPT, /* SIGCKPT */ 175 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 SA_IGNORE, 206 207 }; 208 209 static __inline int 210 sigprop(int sig) 211 { 212 213 if (sig > 0 && sig < NSIG) 214 return (sigproptbl[_SIG_IDX(sig)]); 215 return (0); 216 } 217 218 static __inline int 219 sig_ffs(sigset_t *set) 220 { 221 int i; 222 223 for (i = 0; i < _SIG_WORDS; i++) 224 if (set->__bits[i]) 225 return (ffs(set->__bits[i]) + (i * 32)); 226 return (0); 227 } 228 229 /* 230 * No requirements. 231 */ 232 int 233 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 234 { 235 struct thread *td = curthread; 236 struct proc *p = td->td_proc; 237 struct lwp *lp; 238 struct sigacts *ps = p->p_sigacts; 239 240 if (sig <= 0 || sig > _SIG_MAXSIG) 241 return (EINVAL); 242 243 lwkt_gettoken(&p->p_token); 244 245 if (oact) { 246 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 247 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 248 oact->sa_flags = 0; 249 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 250 oact->sa_flags |= SA_ONSTACK; 251 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 252 oact->sa_flags |= SA_RESTART; 253 if (SIGISMEMBER(ps->ps_sigreset, sig)) 254 oact->sa_flags |= SA_RESETHAND; 255 if (SIGISMEMBER(ps->ps_signodefer, sig)) 256 oact->sa_flags |= SA_NODEFER; 257 if (SIGISMEMBER(ps->ps_siginfo, sig)) 258 oact->sa_flags |= SA_SIGINFO; 259 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 260 oact->sa_flags |= SA_MAILBOX; 261 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 262 oact->sa_flags |= SA_NOCLDSTOP; 263 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 264 oact->sa_flags |= SA_NOCLDWAIT; 265 } 266 if (act) { 267 /* 268 * Check for invalid requests. KILL and STOP cannot be 269 * caught. 270 */ 271 if (sig == SIGKILL || sig == SIGSTOP) { 272 if (act->sa_handler != SIG_DFL) { 273 lwkt_reltoken(&p->p_token); 274 return (EINVAL); 275 } 276 #if 0 277 /* (not needed, SIG_DFL forces action to occur) */ 278 if (act->sa_flags & SA_MAILBOX) { 279 lwkt_reltoken(&p->p_token); 280 return (EINVAL); 281 } 282 #endif 283 } 284 285 /* 286 * Change setting atomically. 287 */ 288 crit_enter(); 289 290 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 291 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 292 if (act->sa_flags & SA_SIGINFO) { 293 ps->ps_sigact[_SIG_IDX(sig)] = 294 (__sighandler_t *)act->sa_sigaction; 295 SIGADDSET(ps->ps_siginfo, sig); 296 } else { 297 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 298 SIGDELSET(ps->ps_siginfo, sig); 299 } 300 if (!(act->sa_flags & SA_RESTART)) 301 SIGADDSET(ps->ps_sigintr, sig); 302 else 303 SIGDELSET(ps->ps_sigintr, sig); 304 if (act->sa_flags & SA_ONSTACK) 305 SIGADDSET(ps->ps_sigonstack, sig); 306 else 307 SIGDELSET(ps->ps_sigonstack, sig); 308 if (act->sa_flags & SA_RESETHAND) 309 SIGADDSET(ps->ps_sigreset, sig); 310 else 311 SIGDELSET(ps->ps_sigreset, sig); 312 if (act->sa_flags & SA_NODEFER) 313 SIGADDSET(ps->ps_signodefer, sig); 314 else 315 SIGDELSET(ps->ps_signodefer, sig); 316 if (act->sa_flags & SA_MAILBOX) 317 SIGADDSET(ps->ps_sigmailbox, sig); 318 else 319 SIGDELSET(ps->ps_sigmailbox, sig); 320 if (sig == SIGCHLD) { 321 if (act->sa_flags & SA_NOCLDSTOP) 322 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 323 else 324 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 325 if (act->sa_flags & SA_NOCLDWAIT) { 326 /* 327 * Paranoia: since SA_NOCLDWAIT is implemented 328 * by reparenting the dying child to PID 1 (and 329 * trust it to reap the zombie), PID 1 itself 330 * is forbidden to set SA_NOCLDWAIT. 331 */ 332 if (p->p_pid == 1) 333 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 334 else 335 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 336 } else { 337 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 338 } 339 } 340 /* 341 * Set bit in p_sigignore for signals that are set to SIG_IGN, 342 * and for signals set to SIG_DFL where the default is to 343 * ignore. However, don't put SIGCONT in p_sigignore, as we 344 * have to restart the process. 345 */ 346 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 347 (sigprop(sig) & SA_IGNORE && 348 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 349 /* never to be seen again */ 350 SIGDELSET(p->p_siglist, sig); 351 /* 352 * Remove the signal also from the thread lists. 353 */ 354 FOREACH_LWP_IN_PROC(lp, p) { 355 SIGDELSET(lp->lwp_siglist, sig); 356 } 357 if (sig != SIGCONT) { 358 /* easier in ksignal */ 359 SIGADDSET(p->p_sigignore, sig); 360 } 361 SIGDELSET(p->p_sigcatch, sig); 362 } else { 363 SIGDELSET(p->p_sigignore, sig); 364 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 365 SIGDELSET(p->p_sigcatch, sig); 366 else 367 SIGADDSET(p->p_sigcatch, sig); 368 } 369 370 crit_exit(); 371 } 372 lwkt_reltoken(&p->p_token); 373 return (0); 374 } 375 376 int 377 sys_sigaction(struct sigaction_args *uap) 378 { 379 struct sigaction act, oact; 380 struct sigaction *actp, *oactp; 381 int error; 382 383 actp = (uap->act != NULL) ? &act : NULL; 384 oactp = (uap->oact != NULL) ? &oact : NULL; 385 if (actp) { 386 error = copyin(uap->act, actp, sizeof(act)); 387 if (error) 388 return (error); 389 } 390 error = kern_sigaction(uap->sig, actp, oactp); 391 if (oactp && !error) { 392 error = copyout(oactp, uap->oact, sizeof(oact)); 393 } 394 return (error); 395 } 396 397 /* 398 * Initialize signal state for process 0; 399 * set to ignore signals that are ignored by default. 400 */ 401 void 402 siginit(struct proc *p) 403 { 404 int i; 405 406 for (i = 1; i <= NSIG; i++) 407 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 408 SIGADDSET(p->p_sigignore, i); 409 } 410 411 /* 412 * Reset signals for an exec of the specified process. 413 */ 414 void 415 execsigs(struct proc *p) 416 { 417 struct sigacts *ps = p->p_sigacts; 418 struct lwp *lp; 419 int sig; 420 421 lp = ONLY_LWP_IN_PROC(p); 422 423 /* 424 * Reset caught signals. Held signals remain held 425 * through p_sigmask (unless they were caught, 426 * and are now ignored by default). 427 */ 428 while (SIGNOTEMPTY(p->p_sigcatch)) { 429 sig = sig_ffs(&p->p_sigcatch); 430 SIGDELSET(p->p_sigcatch, sig); 431 if (sigprop(sig) & SA_IGNORE) { 432 if (sig != SIGCONT) 433 SIGADDSET(p->p_sigignore, sig); 434 SIGDELSET(p->p_siglist, sig); 435 SIGDELSET(lp->lwp_siglist, sig); 436 } 437 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 438 } 439 440 /* 441 * Reset stack state to the user stack. 442 * Clear set of signals caught on the signal stack. 443 */ 444 lp->lwp_sigstk.ss_flags = SS_DISABLE; 445 lp->lwp_sigstk.ss_size = 0; 446 lp->lwp_sigstk.ss_sp = 0; 447 lp->lwp_flag &= ~LWP_ALTSTACK; 448 /* 449 * Reset no zombies if child dies flag as Solaris does. 450 */ 451 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 452 } 453 454 /* 455 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 456 * 457 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 458 * p == curproc. 459 */ 460 int 461 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 462 { 463 struct thread *td = curthread; 464 struct lwp *lp = td->td_lwp; 465 struct proc *p = td->td_proc; 466 int error; 467 468 lwkt_gettoken(&p->p_token); 469 470 if (oset != NULL) 471 *oset = lp->lwp_sigmask; 472 473 error = 0; 474 if (set != NULL) { 475 switch (how) { 476 case SIG_BLOCK: 477 SIG_CANTMASK(*set); 478 SIGSETOR(lp->lwp_sigmask, *set); 479 break; 480 case SIG_UNBLOCK: 481 SIGSETNAND(lp->lwp_sigmask, *set); 482 break; 483 case SIG_SETMASK: 484 SIG_CANTMASK(*set); 485 lp->lwp_sigmask = *set; 486 break; 487 default: 488 error = EINVAL; 489 break; 490 } 491 } 492 493 lwkt_reltoken(&p->p_token); 494 495 return (error); 496 } 497 498 /* 499 * sigprocmask() 500 * 501 * MPSAFE 502 */ 503 int 504 sys_sigprocmask(struct sigprocmask_args *uap) 505 { 506 sigset_t set, oset; 507 sigset_t *setp, *osetp; 508 int error; 509 510 setp = (uap->set != NULL) ? &set : NULL; 511 osetp = (uap->oset != NULL) ? &oset : NULL; 512 if (setp) { 513 error = copyin(uap->set, setp, sizeof(set)); 514 if (error) 515 return (error); 516 } 517 error = kern_sigprocmask(uap->how, setp, osetp); 518 if (osetp && !error) { 519 error = copyout(osetp, uap->oset, sizeof(oset)); 520 } 521 return (error); 522 } 523 524 /* 525 * MPSAFE 526 */ 527 int 528 kern_sigpending(struct __sigset *set) 529 { 530 struct lwp *lp = curthread->td_lwp; 531 532 *set = lwp_sigpend(lp); 533 534 return (0); 535 } 536 537 /* 538 * MPSAFE 539 */ 540 int 541 sys_sigpending(struct sigpending_args *uap) 542 { 543 sigset_t set; 544 int error; 545 546 error = kern_sigpending(&set); 547 548 if (error == 0) 549 error = copyout(&set, uap->set, sizeof(set)); 550 return (error); 551 } 552 553 /* 554 * Suspend process until signal, providing mask to be set 555 * in the meantime. 556 * 557 * MPSAFE 558 */ 559 int 560 kern_sigsuspend(struct __sigset *set) 561 { 562 struct thread *td = curthread; 563 struct lwp *lp = td->td_lwp; 564 struct proc *p = td->td_proc; 565 struct sigacts *ps = p->p_sigacts; 566 567 /* 568 * When returning from sigsuspend, we want 569 * the old mask to be restored after the 570 * signal handler has finished. Thus, we 571 * save it here and mark the sigacts structure 572 * to indicate this. 573 */ 574 lp->lwp_oldsigmask = lp->lwp_sigmask; 575 lp->lwp_flag |= LWP_OLDMASK; 576 577 SIG_CANTMASK(*set); 578 lp->lwp_sigmask = *set; 579 while (tsleep(ps, PCATCH, "pause", 0) == 0) 580 /* void */; 581 /* always return EINTR rather than ERESTART... */ 582 return (EINTR); 583 } 584 585 /* 586 * Note nonstandard calling convention: libc stub passes mask, not 587 * pointer, to save a copyin. 588 * 589 * MPSAFE 590 */ 591 int 592 sys_sigsuspend(struct sigsuspend_args *uap) 593 { 594 sigset_t mask; 595 int error; 596 597 error = copyin(uap->sigmask, &mask, sizeof(mask)); 598 if (error) 599 return (error); 600 601 error = kern_sigsuspend(&mask); 602 603 return (error); 604 } 605 606 /* 607 * MPSAFE 608 */ 609 int 610 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 611 { 612 struct thread *td = curthread; 613 struct lwp *lp = td->td_lwp; 614 struct proc *p = td->td_proc; 615 616 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 617 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 618 619 if (oss) 620 *oss = lp->lwp_sigstk; 621 622 if (ss) { 623 if (ss->ss_flags & SS_DISABLE) { 624 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 625 return (EINVAL); 626 lp->lwp_flag &= ~LWP_ALTSTACK; 627 lp->lwp_sigstk.ss_flags = ss->ss_flags; 628 } else { 629 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 630 return (ENOMEM); 631 lp->lwp_flag |= LWP_ALTSTACK; 632 lp->lwp_sigstk = *ss; 633 } 634 } 635 636 return (0); 637 } 638 639 /* 640 * MPSAFE 641 */ 642 int 643 sys_sigaltstack(struct sigaltstack_args *uap) 644 { 645 stack_t ss, oss; 646 int error; 647 648 if (uap->ss) { 649 error = copyin(uap->ss, &ss, sizeof(ss)); 650 if (error) 651 return (error); 652 } 653 654 error = kern_sigaltstack(uap->ss ? &ss : NULL, 655 uap->oss ? &oss : NULL); 656 657 if (error == 0 && uap->oss) 658 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 659 return (error); 660 } 661 662 /* 663 * Common code for kill process group/broadcast kill. 664 * cp is calling process. 665 */ 666 struct killpg_info { 667 int nfound; 668 int sig; 669 }; 670 671 static int killpg_all_callback(struct proc *p, void *data); 672 673 static int 674 dokillpg(int sig, int pgid, int all) 675 { 676 struct killpg_info info; 677 struct proc *cp = curproc; 678 struct proc *p; 679 struct pgrp *pgrp; 680 681 info.nfound = 0; 682 info.sig = sig; 683 684 if (all) { 685 /* 686 * broadcast 687 */ 688 allproc_scan(killpg_all_callback, &info); 689 } else { 690 if (pgid == 0) { 691 /* 692 * zero pgid means send to my process group. 693 */ 694 pgrp = cp->p_pgrp; 695 pgref(pgrp); 696 } else { 697 pgrp = pgfind(pgid); 698 if (pgrp == NULL) 699 return (ESRCH); 700 } 701 702 /* 703 * Must interlock all signals against fork 704 */ 705 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 706 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 707 if (p->p_pid <= 1 || 708 p->p_stat == SZOMB || 709 (p->p_flag & P_SYSTEM) || 710 !CANSIGNAL(p, sig)) { 711 continue; 712 } 713 ++info.nfound; 714 if (sig) 715 ksignal(p, sig); 716 } 717 lockmgr(&pgrp->pg_lock, LK_RELEASE); 718 pgrel(pgrp); 719 } 720 return (info.nfound ? 0 : ESRCH); 721 } 722 723 static int 724 killpg_all_callback(struct proc *p, void *data) 725 { 726 struct killpg_info *info = data; 727 728 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 729 p == curproc || !CANSIGNAL(p, info->sig)) { 730 return (0); 731 } 732 ++info->nfound; 733 if (info->sig) 734 ksignal(p, info->sig); 735 return(0); 736 } 737 738 /* 739 * Send a general signal to a process or LWPs within that process. Note 740 * that new signals cannot be sent if a process is exiting. 741 * 742 * No requirements. 743 */ 744 int 745 kern_kill(int sig, pid_t pid, lwpid_t tid) 746 { 747 int t; 748 749 if ((u_int)sig > _SIG_MAXSIG) 750 return (EINVAL); 751 752 lwkt_gettoken(&proc_token); 753 754 if (pid > 0) { 755 struct proc *p; 756 struct lwp *lp = NULL; 757 758 /* kill single process */ 759 if ((p = pfind(pid)) == NULL) { 760 lwkt_reltoken(&proc_token); 761 return (ESRCH); 762 } 763 lwkt_gettoken(&p->p_token); 764 if (!CANSIGNAL(p, sig)) { 765 lwkt_reltoken(&p->p_token); 766 PRELE(p); 767 lwkt_reltoken(&proc_token); 768 return (EPERM); 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_flag & P_WEXIT) { 777 lwkt_reltoken(&p->p_token); 778 PRELE(p); 779 lwkt_reltoken(&proc_token); 780 return (0); 781 } 782 if (tid != -1) { 783 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 784 if (lp == NULL) { 785 lwkt_reltoken(&p->p_token); 786 PRELE(p); 787 lwkt_reltoken(&proc_token); 788 return (ESRCH); 789 } 790 } 791 if (sig) 792 lwpsignal(p, lp, sig); 793 lwkt_reltoken(&p->p_token); 794 PRELE(p); 795 lwkt_reltoken(&proc_token); 796 return (0); 797 } 798 799 /* 800 * If we come here, pid is a special broadcast pid. 801 * This doesn't mix with a tid. 802 */ 803 if (tid != -1) { 804 lwkt_reltoken(&proc_token); 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 lwkt_reltoken(&proc_token); 819 return t; 820 } 821 822 int 823 sys_kill(struct kill_args *uap) 824 { 825 int error; 826 827 error = kern_kill(uap->signum, uap->pid, -1); 828 return (error); 829 } 830 831 int 832 sys_lwp_kill(struct lwp_kill_args *uap) 833 { 834 int error; 835 pid_t pid = uap->pid; 836 837 /* 838 * A tid is mandatory for lwp_kill(), otherwise 839 * you could simply use kill(). 840 */ 841 if (uap->tid == -1) 842 return (EINVAL); 843 844 /* 845 * To save on a getpid() function call for intra-process 846 * signals, pid == -1 means current process. 847 */ 848 if (pid == -1) 849 pid = curproc->p_pid; 850 851 error = kern_kill(uap->signum, pid, uap->tid); 852 return (error); 853 } 854 855 /* 856 * Send a signal to a process group. 857 */ 858 void 859 gsignal(int pgid, int sig) 860 { 861 struct pgrp *pgrp; 862 863 if (pgid && (pgrp = pgfind(pgid))) 864 pgsignal(pgrp, sig, 0); 865 } 866 867 /* 868 * Send a signal to a process group. If checktty is 1, 869 * limit to members which have a controlling terminal. 870 * 871 * pg_lock interlocks against a fork that might be in progress, to 872 * ensure that the new child process picks up the signal. 873 */ 874 void 875 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 876 { 877 struct proc *p; 878 879 /* 880 * Must interlock all signals against fork 881 */ 882 if (pgrp) { 883 pgref(pgrp); 884 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 885 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 886 if (checkctty == 0 || p->p_flag & P_CONTROLT) 887 ksignal(p, sig); 888 } 889 lockmgr(&pgrp->pg_lock, LK_RELEASE); 890 pgrel(pgrp); 891 } 892 } 893 894 /* 895 * Send a signal caused by a trap to the current lwp. If it will be caught 896 * immediately, deliver it with correct code. Otherwise, post it normally. 897 * 898 * These signals may ONLY be delivered to the specified lwp and may never 899 * be delivered to the process generically. 900 */ 901 void 902 trapsignal(struct lwp *lp, int sig, u_long code) 903 { 904 struct proc *p = lp->lwp_proc; 905 struct sigacts *ps = p->p_sigacts; 906 907 /* 908 * If we are a virtual kernel running an emulated user process 909 * context, switch back to the virtual kernel context before 910 * trying to post the signal. 911 */ 912 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 913 struct trapframe *tf = lp->lwp_md.md_regs; 914 tf->tf_trapno = 0; 915 vkernel_trap(lp, tf); 916 } 917 918 919 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 920 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 921 lp->lwp_ru.ru_nsignals++; 922 #ifdef KTRACE 923 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 924 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 925 &lp->lwp_sigmask, code); 926 #endif 927 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 928 &lp->lwp_sigmask, code); 929 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 930 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 931 SIGADDSET(lp->lwp_sigmask, sig); 932 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 933 /* 934 * See kern_sigaction() for origin of this code. 935 */ 936 SIGDELSET(p->p_sigcatch, sig); 937 if (sig != SIGCONT && 938 sigprop(sig) & SA_IGNORE) 939 SIGADDSET(p->p_sigignore, sig); 940 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 941 } 942 } else { 943 lp->lwp_code = code; /* XXX for core dump/debugger */ 944 lp->lwp_sig = sig; /* XXX to verify code */ 945 lwpsignal(p, lp, sig); 946 } 947 } 948 949 /* 950 * Find a suitable lwp to deliver the signal to. Returns NULL if all 951 * lwps hold the signal blocked. 952 * 953 * Caller must hold p->p_token. 954 */ 955 static struct lwp * 956 find_lwp_for_signal(struct proc *p, int sig) 957 { 958 struct lwp *lp; 959 struct lwp *run, *sleep, *stop; 960 961 /* 962 * If the running/preempted thread belongs to the proc to which 963 * the signal is being delivered and this thread does not block 964 * the signal, then we can avoid a context switch by delivering 965 * the signal to this thread, because it will return to userland 966 * soon anyways. 967 */ 968 lp = lwkt_preempted_proc(); 969 if (lp != NULL && lp->lwp_proc == p && 970 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 971 return (lp); 972 } 973 974 run = sleep = stop = NULL; 975 FOREACH_LWP_IN_PROC(lp, p) { 976 /* 977 * If the signal is being blocked by the lwp, then this 978 * lwp is not eligible for receiving the signal. 979 */ 980 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 981 continue; 982 983 switch (lp->lwp_stat) { 984 case LSRUN: 985 run = lp; 986 break; 987 988 case LSSTOP: 989 stop = lp; 990 break; 991 992 case LSSLEEP: 993 if (lp->lwp_flag & LWP_SINTR) 994 sleep = lp; 995 break; 996 } 997 } 998 999 if (run != NULL) 1000 return (run); 1001 else if (sleep != NULL) 1002 return (sleep); 1003 else 1004 return (stop); 1005 } 1006 1007 /* 1008 * Send the signal to the process. If the signal has an action, the action 1009 * is usually performed by the target process rather than the caller; we add 1010 * the signal to the set of pending signals for the process. 1011 * 1012 * Exceptions: 1013 * o When a stop signal is sent to a sleeping process that takes the 1014 * default action, the process is stopped without awakening it. 1015 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1016 * regardless of the signal action (eg, blocked or ignored). 1017 * 1018 * Other ignored signals are discarded immediately. 1019 * 1020 * If the caller wishes to call this function from a hard code section the 1021 * caller must already hold p->p_token (see kern_clock.c). 1022 * 1023 * No requirements. 1024 */ 1025 void 1026 ksignal(struct proc *p, int sig) 1027 { 1028 lwpsignal(p, NULL, sig); 1029 } 1030 1031 /* 1032 * The core for ksignal. lp may be NULL, then a suitable thread 1033 * will be chosen. If not, lp MUST be a member of p. 1034 * 1035 * If the caller wishes to call this function from a hard code section the 1036 * caller must already hold p->p_token. 1037 * 1038 * No requirements. 1039 */ 1040 void 1041 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1042 { 1043 int prop; 1044 sig_t action; 1045 1046 if (sig > _SIG_MAXSIG || sig <= 0) { 1047 kprintf("lwpsignal: signal %d\n", sig); 1048 panic("lwpsignal signal number"); 1049 } 1050 1051 KKASSERT(lp == NULL || lp->lwp_proc == p); 1052 1053 PHOLD(p); 1054 lwkt_gettoken(&p->p_token); 1055 1056 prop = sigprop(sig); 1057 1058 /* 1059 * If proc is traced, always give parent a chance; 1060 * if signal event is tracked by procfs, give *that* 1061 * a chance, as well. 1062 */ 1063 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1064 action = SIG_DFL; 1065 } else { 1066 /* 1067 * Do not try to deliver signals to an exiting lwp. Note 1068 * that we must still deliver the signal if P_WEXIT is set 1069 * in the process flags. 1070 */ 1071 if (lp && (lp->lwp_flag & LWP_WEXIT)) { 1072 lwkt_reltoken(&p->p_token); 1073 PRELE(p); 1074 return; 1075 } 1076 1077 /* 1078 * If the signal is being ignored, then we forget about 1079 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1080 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1081 */ 1082 if (SIGISMEMBER(p->p_sigignore, sig)) { 1083 lwkt_reltoken(&p->p_token); 1084 PRELE(p); 1085 return; 1086 } 1087 if (SIGISMEMBER(p->p_sigcatch, sig)) 1088 action = SIG_CATCH; 1089 else 1090 action = SIG_DFL; 1091 } 1092 1093 /* 1094 * If continuing, clear any pending STOP signals. 1095 */ 1096 if (prop & SA_CONT) 1097 SIG_STOPSIGMASK(p->p_siglist); 1098 1099 if (prop & SA_STOP) { 1100 /* 1101 * If sending a tty stop signal to a member of an orphaned 1102 * process group, discard the signal here if the action 1103 * is default; don't stop the process below if sleeping, 1104 * and don't clear any pending SIGCONT. 1105 */ 1106 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1107 action == SIG_DFL) { 1108 lwkt_reltoken(&p->p_token); 1109 PRELE(p); 1110 return; 1111 } 1112 SIG_CONTSIGMASK(p->p_siglist); 1113 p->p_flag &= ~P_CONTINUED; 1114 } 1115 1116 crit_enter(); 1117 1118 if (p->p_stat == SSTOP) { 1119 /* 1120 * Nobody can handle this signal, add it to the lwp or 1121 * process pending list 1122 */ 1123 if (lp) 1124 SIGADDSET(lp->lwp_siglist, sig); 1125 else 1126 SIGADDSET(p->p_siglist, sig); 1127 1128 /* 1129 * If the process is stopped and is being traced, then no 1130 * further action is necessary. 1131 */ 1132 if (p->p_flag & P_TRACED) 1133 goto out; 1134 1135 /* 1136 * If the process is stopped and receives a KILL signal, 1137 * make the process runnable. 1138 */ 1139 if (sig == SIGKILL) { 1140 proc_unstop(p); 1141 goto active_process; 1142 } 1143 1144 /* 1145 * If the process is stopped and receives a CONT signal, 1146 * then try to make the process runnable again. 1147 */ 1148 if (prop & SA_CONT) { 1149 /* 1150 * If SIGCONT is default (or ignored), we continue the 1151 * process but don't leave the signal in p_siglist, as 1152 * it has no further action. If SIGCONT is held, we 1153 * continue the process and leave the signal in 1154 * p_siglist. If the process catches SIGCONT, let it 1155 * handle the signal itself. 1156 */ 1157 /* XXX what if the signal is being held blocked? */ 1158 p->p_flag |= P_CONTINUED; 1159 wakeup(p->p_pptr); 1160 if (action == SIG_DFL) 1161 SIGDELSET(p->p_siglist, sig); 1162 proc_unstop(p); 1163 if (action == SIG_CATCH) 1164 goto active_process; 1165 goto out; 1166 } 1167 1168 /* 1169 * If the process is stopped and receives another STOP 1170 * signal, we do not need to stop it again. If we did 1171 * the shell could get confused. 1172 * 1173 * However, if the current/preempted lwp is part of the 1174 * process receiving the signal, we need to keep it, 1175 * so that this lwp can stop in issignal() later, as 1176 * we don't want to wait until it reaches userret! 1177 */ 1178 if (prop & SA_STOP) { 1179 if (lwkt_preempted_proc() == NULL || 1180 lwkt_preempted_proc()->lwp_proc != p) 1181 SIGDELSET(p->p_siglist, sig); 1182 } 1183 1184 /* 1185 * Otherwise the process is stopped and it received some 1186 * signal, which does not change its stopped state. 1187 * 1188 * We have to select one thread to set LWP_BREAKTSLEEP, 1189 * so that the current signal will break the sleep 1190 * as soon as a SA_CONT signal will unstop the process. 1191 */ 1192 if (lp == NULL) 1193 lp = find_lwp_for_signal(p, sig); 1194 if (lp != NULL && 1195 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1196 lp->lwp_flag |= LWP_BREAKTSLEEP; 1197 goto out; 1198 1199 /* NOTREACHED */ 1200 } 1201 /* else not stopped */ 1202 active_process: 1203 1204 /* 1205 * Never deliver a lwp-specific signal to a random lwp. 1206 */ 1207 if (lp == NULL) { 1208 lp = find_lwp_for_signal(p, sig); 1209 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1210 lp = NULL; 1211 } 1212 1213 /* 1214 * Deliver to the process generically if (1) the signal is being 1215 * sent to any thread or (2) we could not find a thread to deliver 1216 * it to. 1217 */ 1218 if (lp == NULL) { 1219 SIGADDSET(p->p_siglist, sig); 1220 goto out; 1221 } 1222 1223 /* 1224 * Deliver to a specific LWP whether it masks it or not. It will 1225 * not be dispatched if masked but we must still deliver it. 1226 */ 1227 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1228 (p->p_flag & P_TRACED) == 0) { 1229 p->p_nice = NZERO; 1230 } 1231 1232 /* 1233 * If the process receives a STOP signal which indeed needs to 1234 * stop the process, do so. If the process chose to catch the 1235 * signal, it will be treated like any other signal. 1236 */ 1237 if ((prop & SA_STOP) && action == SIG_DFL) { 1238 /* 1239 * If a child holding parent blocked, stopping 1240 * could cause deadlock. Take no action at this 1241 * time. 1242 */ 1243 if (p->p_flag & P_PPWAIT) { 1244 SIGADDSET(p->p_siglist, sig); 1245 goto out; 1246 } 1247 1248 /* 1249 * Do not actually try to manipulate the process, but simply 1250 * stop it. Lwps will stop as soon as they safely can. 1251 */ 1252 p->p_xstat = sig; 1253 proc_stop(p); 1254 goto out; 1255 } 1256 1257 /* 1258 * If it is a CONT signal with default action, just ignore it. 1259 */ 1260 if ((prop & SA_CONT) && action == SIG_DFL) 1261 goto out; 1262 1263 /* 1264 * Mark signal pending at this specific thread. 1265 */ 1266 SIGADDSET(lp->lwp_siglist, sig); 1267 1268 lwp_signotify(lp); 1269 1270 out: 1271 lwkt_reltoken(&p->p_token); 1272 PRELE(p); 1273 crit_exit(); 1274 } 1275 1276 /* 1277 * p->p_token must be held 1278 */ 1279 static void 1280 lwp_signotify(struct lwp *lp) 1281 { 1282 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1283 crit_enter(); 1284 1285 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1286 /* 1287 * Thread is in tsleep. 1288 */ 1289 1290 /* 1291 * If the thread is sleeping uninterruptibly 1292 * we can't interrupt the sleep... the signal will 1293 * be noticed when the lwp returns through 1294 * trap() or syscall(). 1295 * 1296 * Otherwise the signal can interrupt the sleep. 1297 * 1298 * If the process is traced, the lwp will handle the 1299 * tracing in issignal() when it returns to userland. 1300 */ 1301 if (lp->lwp_flag & LWP_SINTR) { 1302 /* 1303 * Make runnable and break out of any tsleep as well. 1304 */ 1305 lp->lwp_flag |= LWP_BREAKTSLEEP; 1306 setrunnable(lp); 1307 } 1308 } else { 1309 /* 1310 * Otherwise the thread is running 1311 * 1312 * LSRUN does nothing with the signal, other than kicking 1313 * ourselves if we are running. 1314 * SZOMB and SIDL mean that it will either never be noticed, 1315 * or noticed very soon. 1316 * 1317 * Note that lwp_thread may be NULL or may not be completely 1318 * initialized if the process is in the SIDL or SZOMB state. 1319 * 1320 * For SMP we may have to forward the request to another cpu. 1321 * YYY the MP lock prevents the target process from moving 1322 * to another cpu, see kern/kern_switch.c 1323 * 1324 * If the target thread is waiting on its message port, 1325 * wakeup the target thread so it can check (or ignore) 1326 * the new signal. YYY needs cleanup. 1327 */ 1328 if (lp == lwkt_preempted_proc()) { 1329 signotify(); 1330 } else if (lp->lwp_stat == LSRUN) { 1331 struct thread *td = lp->lwp_thread; 1332 struct proc *p __debugvar = lp->lwp_proc; 1333 1334 KASSERT(td != NULL, 1335 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1336 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1337 p->p_flag, lp->lwp_flag)); 1338 1339 /* 1340 * To prevent a MP race with TDF_SINTR we must 1341 * schedule the thread on the correct cpu. 1342 */ 1343 #ifdef SMP 1344 if (td->td_gd != mycpu) { 1345 LWPHOLD(lp); 1346 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1347 } else 1348 #endif 1349 if (td->td_flags & TDF_SINTR) 1350 lwkt_schedule(td); 1351 } 1352 } 1353 crit_exit(); 1354 } 1355 1356 #ifdef SMP 1357 1358 /* 1359 * This function is called via an IPI. We will be in a critical section but 1360 * the MP lock will NOT be held. The passed lp will be held. 1361 * 1362 * We must essentially repeat the code at the end of lwp_signotify(), 1363 * in particular rechecking all races. If we are still not on the 1364 * correct cpu we leave the lwp ref intact and continue the chase. 1365 * 1366 * XXX this may still not be entirely correct, since we are checking 1367 * lwp_stat asynchronously. 1368 */ 1369 static void 1370 signotify_remote(void *arg) 1371 { 1372 struct lwp *lp = arg; 1373 thread_t td; 1374 1375 if (lp == lwkt_preempted_proc()) { 1376 signotify(); 1377 } else if (lp->lwp_stat == LSRUN) { 1378 /* 1379 * To prevent a MP race with TDF_SINTR we must 1380 * schedule the thread on the correct cpu. 1381 */ 1382 td = lp->lwp_thread; 1383 if (td->td_gd != mycpu) { 1384 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1385 return; 1386 /* NOT REACHED */ 1387 } 1388 if (td->td_flags & TDF_SINTR) 1389 lwkt_schedule(td); 1390 } 1391 LWPRELE(lp); 1392 } 1393 1394 #endif 1395 1396 /* 1397 * Caller must hold p->p_token 1398 */ 1399 void 1400 proc_stop(struct proc *p) 1401 { 1402 struct lwp *lp; 1403 1404 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1405 crit_enter(); 1406 1407 /* If somebody raced us, be happy with it */ 1408 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1409 crit_exit(); 1410 return; 1411 } 1412 p->p_stat = SSTOP; 1413 1414 FOREACH_LWP_IN_PROC(lp, p) { 1415 switch (lp->lwp_stat) { 1416 case LSSTOP: 1417 /* 1418 * Do nothing, we are already counted in 1419 * p_nstopped. 1420 */ 1421 break; 1422 1423 case LSSLEEP: 1424 /* 1425 * We're sleeping, but we will stop before 1426 * returning to userspace, so count us 1427 * as stopped as well. We set LWP_WSTOP 1428 * to signal the lwp that it should not 1429 * increase p_nstopped when reaching tstop(). 1430 */ 1431 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1432 lp->lwp_flag |= LWP_WSTOP; 1433 ++p->p_nstopped; 1434 } 1435 break; 1436 1437 case LSRUN: 1438 /* 1439 * We might notify ourself, but that's not 1440 * a problem. 1441 */ 1442 lwp_signotify(lp); 1443 break; 1444 } 1445 } 1446 1447 if (p->p_nstopped == p->p_nthreads) { 1448 p->p_flag &= ~P_WAITED; 1449 wakeup(p->p_pptr); 1450 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1451 ksignal(p->p_pptr, SIGCHLD); 1452 } 1453 crit_exit(); 1454 } 1455 1456 /* 1457 * Caller must hold proc_token 1458 */ 1459 void 1460 proc_unstop(struct proc *p) 1461 { 1462 struct lwp *lp; 1463 1464 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1465 crit_enter(); 1466 1467 if (p->p_stat != SSTOP) { 1468 crit_exit(); 1469 return; 1470 } 1471 1472 p->p_stat = SACTIVE; 1473 1474 FOREACH_LWP_IN_PROC(lp, p) { 1475 switch (lp->lwp_stat) { 1476 case LSRUN: 1477 /* 1478 * Uh? Not stopped? Well, I guess that's okay. 1479 */ 1480 if (bootverbose) 1481 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1482 p->p_pid, lp->lwp_tid); 1483 break; 1484 1485 case LSSLEEP: 1486 /* 1487 * Still sleeping. Don't bother waking it up. 1488 * However, if this thread was counted as 1489 * stopped, undo this. 1490 * 1491 * Nevertheless we call setrunnable() so that it 1492 * will wake up in case a signal or timeout arrived 1493 * in the meantime. 1494 */ 1495 if (lp->lwp_flag & LWP_WSTOP) { 1496 lp->lwp_flag &= ~LWP_WSTOP; 1497 --p->p_nstopped; 1498 } else { 1499 if (bootverbose) 1500 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1501 p->p_pid, lp->lwp_tid); 1502 } 1503 /* FALLTHROUGH */ 1504 1505 case LSSTOP: 1506 setrunnable(lp); 1507 break; 1508 1509 } 1510 } 1511 crit_exit(); 1512 } 1513 1514 /* 1515 * No requirements. 1516 */ 1517 static int 1518 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1519 { 1520 sigset_t savedmask, set; 1521 struct proc *p = curproc; 1522 struct lwp *lp = curthread->td_lwp; 1523 int error, sig, hz, timevalid = 0; 1524 struct timespec rts, ets, ts; 1525 struct timeval tv; 1526 1527 error = 0; 1528 sig = 0; 1529 ets.tv_sec = 0; /* silence compiler warning */ 1530 ets.tv_nsec = 0; /* silence compiler warning */ 1531 SIG_CANTMASK(waitset); 1532 savedmask = lp->lwp_sigmask; 1533 1534 if (timeout) { 1535 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1536 timeout->tv_nsec < 1000000000) { 1537 timevalid = 1; 1538 getnanouptime(&rts); 1539 ets = rts; 1540 timespecadd(&ets, timeout); 1541 } 1542 } 1543 1544 for (;;) { 1545 set = lwp_sigpend(lp); 1546 SIGSETAND(set, waitset); 1547 if ((sig = sig_ffs(&set)) != 0) { 1548 SIGFILLSET(lp->lwp_sigmask); 1549 SIGDELSET(lp->lwp_sigmask, sig); 1550 SIG_CANTMASK(lp->lwp_sigmask); 1551 sig = issignal(lp, 1); 1552 /* 1553 * It may be a STOP signal, in the case, issignal 1554 * returns 0, because we may stop there, and new 1555 * signal can come in, we should restart if we got 1556 * nothing. 1557 */ 1558 if (sig == 0) 1559 continue; 1560 else 1561 break; 1562 } 1563 1564 /* 1565 * Previous checking got nothing, and we retried but still 1566 * got nothing, we should return the error status. 1567 */ 1568 if (error) 1569 break; 1570 1571 /* 1572 * POSIX says this must be checked after looking for pending 1573 * signals. 1574 */ 1575 if (timeout) { 1576 if (timevalid == 0) { 1577 error = EINVAL; 1578 break; 1579 } 1580 getnanouptime(&rts); 1581 if (timespeccmp(&rts, &ets, >=)) { 1582 error = EAGAIN; 1583 break; 1584 } 1585 ts = ets; 1586 timespecsub(&ts, &rts); 1587 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1588 hz = tvtohz_high(&tv); 1589 } else { 1590 hz = 0; 1591 } 1592 1593 lp->lwp_sigmask = savedmask; 1594 SIGSETNAND(lp->lwp_sigmask, waitset); 1595 /* 1596 * We won't ever be woken up. Instead, our sleep will 1597 * be broken in lwpsignal(). 1598 */ 1599 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1600 if (timeout) { 1601 if (error == ERESTART) { 1602 /* can not restart a timeout wait. */ 1603 error = EINTR; 1604 } else if (error == EAGAIN) { 1605 /* will calculate timeout by ourself. */ 1606 error = 0; 1607 } 1608 } 1609 /* Retry ... */ 1610 } 1611 1612 lp->lwp_sigmask = savedmask; 1613 if (sig) { 1614 error = 0; 1615 bzero(info, sizeof(*info)); 1616 info->si_signo = sig; 1617 lwp_delsig(lp, sig); /* take the signal! */ 1618 1619 if (sig == SIGKILL) { 1620 sigexit(lp, sig); 1621 /* NOT REACHED */ 1622 } 1623 } 1624 1625 return (error); 1626 } 1627 1628 /* 1629 * MPALMOSTSAFE 1630 */ 1631 int 1632 sys_sigtimedwait(struct sigtimedwait_args *uap) 1633 { 1634 struct timespec ts; 1635 struct timespec *timeout; 1636 sigset_t set; 1637 siginfo_t info; 1638 int error; 1639 1640 if (uap->timeout) { 1641 error = copyin(uap->timeout, &ts, sizeof(ts)); 1642 if (error) 1643 return (error); 1644 timeout = &ts; 1645 } else { 1646 timeout = NULL; 1647 } 1648 error = copyin(uap->set, &set, sizeof(set)); 1649 if (error) 1650 return (error); 1651 error = kern_sigtimedwait(set, &info, timeout); 1652 if (error) 1653 return (error); 1654 if (uap->info) 1655 error = copyout(&info, uap->info, sizeof(info)); 1656 /* Repost if we got an error. */ 1657 /* 1658 * XXX lwp 1659 * 1660 * This could transform a thread-specific signal to another 1661 * thread / process pending signal. 1662 */ 1663 if (error) { 1664 ksignal(curproc, info.si_signo); 1665 } else { 1666 uap->sysmsg_result = info.si_signo; 1667 } 1668 return (error); 1669 } 1670 1671 /* 1672 * MPALMOSTSAFE 1673 */ 1674 int 1675 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1676 { 1677 siginfo_t info; 1678 sigset_t set; 1679 int error; 1680 1681 error = copyin(uap->set, &set, sizeof(set)); 1682 if (error) 1683 return (error); 1684 error = kern_sigtimedwait(set, &info, NULL); 1685 if (error) 1686 return (error); 1687 if (uap->info) 1688 error = copyout(&info, uap->info, sizeof(info)); 1689 /* Repost if we got an error. */ 1690 /* 1691 * XXX lwp 1692 * 1693 * This could transform a thread-specific signal to another 1694 * thread / process pending signal. 1695 */ 1696 if (error) { 1697 ksignal(curproc, info.si_signo); 1698 } else { 1699 uap->sysmsg_result = info.si_signo; 1700 } 1701 return (error); 1702 } 1703 1704 /* 1705 * If the current process has received a signal that would interrupt a 1706 * system call, return EINTR or ERESTART as appropriate. 1707 */ 1708 int 1709 iscaught(struct lwp *lp) 1710 { 1711 struct proc *p = lp->lwp_proc; 1712 int sig; 1713 1714 if (p) { 1715 if ((sig = CURSIG(lp)) != 0) { 1716 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1717 return (EINTR); 1718 return (ERESTART); 1719 } 1720 } 1721 return(EWOULDBLOCK); 1722 } 1723 1724 /* 1725 * If the current process has received a signal (should be caught or cause 1726 * termination, should interrupt current syscall), return the signal number. 1727 * Stop signals with default action are processed immediately, then cleared; 1728 * they aren't returned. This is checked after each entry to the system for 1729 * a syscall or trap (though this can usually be done without calling issignal 1730 * by checking the pending signal masks in the CURSIG macro). 1731 * 1732 * This routine is called via CURSIG/__cursig. We will acquire and release 1733 * p->p_token but if the caller needs to interlock the test the caller must 1734 * also hold p->p_token. 1735 * 1736 * while (sig = CURSIG(curproc)) 1737 * postsig(sig); 1738 * 1739 * MPSAFE 1740 */ 1741 int 1742 issignal(struct lwp *lp, int maytrace) 1743 { 1744 struct proc *p = lp->lwp_proc; 1745 sigset_t mask; 1746 int sig, prop; 1747 1748 lwkt_gettoken(&p->p_token); 1749 1750 for (;;) { 1751 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1752 1753 /* 1754 * If this process is supposed to stop, stop this thread. 1755 */ 1756 if (p->p_stat == SSTOP) 1757 tstop(); 1758 1759 mask = lwp_sigpend(lp); 1760 SIGSETNAND(mask, lp->lwp_sigmask); 1761 if (p->p_flag & P_PPWAIT) 1762 SIG_STOPSIGMASK(mask); 1763 if (SIGISEMPTY(mask)) { /* no signal to send */ 1764 lwkt_reltoken(&p->p_token); 1765 return (0); 1766 } 1767 sig = sig_ffs(&mask); 1768 1769 STOPEVENT(p, S_SIG, sig); 1770 1771 /* 1772 * We should see pending but ignored signals 1773 * only if P_TRACED was on when they were posted. 1774 */ 1775 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1776 lwp_delsig(lp, sig); 1777 continue; 1778 } 1779 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1780 /* 1781 * If traced, always stop, and stay stopped until 1782 * released by the parent. 1783 * 1784 * NOTE: SSTOP may get cleared during the loop, 1785 * but we do not re-notify the parent if we have 1786 * to loop several times waiting for the parent 1787 * to let us continue. 1788 * 1789 * XXX not sure if this is still true 1790 */ 1791 p->p_xstat = sig; 1792 proc_stop(p); 1793 do { 1794 tstop(); 1795 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1796 1797 /* 1798 * If parent wants us to take the signal, 1799 * then it will leave it in p->p_xstat; 1800 * otherwise we just look for signals again. 1801 */ 1802 lwp_delsig(lp, sig); /* clear old signal */ 1803 sig = p->p_xstat; 1804 if (sig == 0) 1805 continue; 1806 1807 /* 1808 * Put the new signal into p_siglist. If the 1809 * signal is being masked, look for other signals. 1810 * 1811 * XXX lwp might need a call to ksignal() 1812 */ 1813 SIGADDSET(p->p_siglist, sig); 1814 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1815 continue; 1816 1817 /* 1818 * If the traced bit got turned off, go back up 1819 * to the top to rescan signals. This ensures 1820 * that p_sig* and ps_sigact are consistent. 1821 */ 1822 if ((p->p_flag & P_TRACED) == 0) 1823 continue; 1824 } 1825 1826 prop = sigprop(sig); 1827 1828 /* 1829 * Decide whether the signal should be returned. 1830 * Return the signal's number, or fall through 1831 * to clear it from the pending mask. 1832 */ 1833 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1834 case (intptr_t)SIG_DFL: 1835 /* 1836 * Don't take default actions on system processes. 1837 */ 1838 if (p->p_pid <= 1) { 1839 #ifdef DIAGNOSTIC 1840 /* 1841 * Are you sure you want to ignore SIGSEGV 1842 * in init? XXX 1843 */ 1844 kprintf("Process (pid %lu) got signal %d\n", 1845 (u_long)p->p_pid, sig); 1846 #endif 1847 break; /* == ignore */ 1848 } 1849 1850 /* 1851 * Handle the in-kernel checkpoint action 1852 */ 1853 if (prop & SA_CKPT) { 1854 checkpoint_signal_handler(lp); 1855 break; 1856 } 1857 1858 /* 1859 * If there is a pending stop signal to process 1860 * with default action, stop here, 1861 * then clear the signal. However, 1862 * if process is member of an orphaned 1863 * process group, ignore tty stop signals. 1864 */ 1865 if (prop & SA_STOP) { 1866 if (p->p_flag & P_TRACED || 1867 (p->p_pgrp->pg_jobc == 0 && 1868 prop & SA_TTYSTOP)) 1869 break; /* == ignore */ 1870 p->p_xstat = sig; 1871 proc_stop(p); 1872 tstop(); 1873 break; 1874 } else if (prop & SA_IGNORE) { 1875 /* 1876 * Except for SIGCONT, shouldn't get here. 1877 * Default action is to ignore; drop it. 1878 */ 1879 break; /* == ignore */ 1880 } else { 1881 lwkt_reltoken(&p->p_token); 1882 return (sig); 1883 } 1884 1885 /*NOTREACHED*/ 1886 1887 case (intptr_t)SIG_IGN: 1888 /* 1889 * Masking above should prevent us ever trying 1890 * to take action on an ignored signal other 1891 * than SIGCONT, unless process is traced. 1892 */ 1893 if ((prop & SA_CONT) == 0 && 1894 (p->p_flag & P_TRACED) == 0) 1895 kprintf("issignal\n"); 1896 break; /* == ignore */ 1897 1898 default: 1899 /* 1900 * This signal has an action, let 1901 * postsig() process it. 1902 */ 1903 lwkt_reltoken(&p->p_token); 1904 return (sig); 1905 } 1906 lwp_delsig(lp, sig); /* take the signal! */ 1907 } 1908 /* NOTREACHED */ 1909 } 1910 1911 /* 1912 * Take the action for the specified signal 1913 * from the current set of pending signals. 1914 */ 1915 void 1916 postsig(int sig) 1917 { 1918 struct lwp *lp = curthread->td_lwp; 1919 struct proc *p = lp->lwp_proc; 1920 struct sigacts *ps = p->p_sigacts; 1921 sig_t action; 1922 sigset_t returnmask; 1923 int code; 1924 1925 KASSERT(sig != 0, ("postsig")); 1926 1927 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1928 1929 /* 1930 * If we are a virtual kernel running an emulated user process 1931 * context, switch back to the virtual kernel context before 1932 * trying to post the signal. 1933 */ 1934 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1935 struct trapframe *tf = lp->lwp_md.md_regs; 1936 tf->tf_trapno = 0; 1937 vkernel_trap(lp, tf); 1938 } 1939 1940 lwp_delsig(lp, sig); 1941 action = ps->ps_sigact[_SIG_IDX(sig)]; 1942 #ifdef KTRACE 1943 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1944 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1945 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1946 #endif 1947 STOPEVENT(p, S_SIG, sig); 1948 1949 if (action == SIG_DFL) { 1950 /* 1951 * Default action, where the default is to kill 1952 * the process. (Other cases were ignored above.) 1953 */ 1954 sigexit(lp, sig); 1955 /* NOTREACHED */ 1956 } else { 1957 /* 1958 * If we get here, the signal must be caught. 1959 */ 1960 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1961 ("postsig action")); 1962 1963 crit_enter(); 1964 1965 /* 1966 * Reset the signal handler if asked to 1967 */ 1968 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1969 /* 1970 * See kern_sigaction() for origin of this code. 1971 */ 1972 SIGDELSET(p->p_sigcatch, sig); 1973 if (sig != SIGCONT && 1974 sigprop(sig) & SA_IGNORE) 1975 SIGADDSET(p->p_sigignore, sig); 1976 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1977 } 1978 1979 /* 1980 * Handle the mailbox case. Copyout to the appropriate 1981 * location but do not generate a signal frame. The system 1982 * call simply returns EINTR and the user is responsible for 1983 * polling the mailbox. 1984 */ 1985 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1986 int sig_copy = sig; 1987 copyout(&sig_copy, (void *)action, sizeof(int)); 1988 curproc->p_flag |= P_MAILBOX; 1989 crit_exit(); 1990 goto done; 1991 } 1992 1993 /* 1994 * Set the signal mask and calculate the mask to restore 1995 * when the signal function returns. 1996 * 1997 * Special case: user has done a sigsuspend. Here the 1998 * current mask is not of interest, but rather the 1999 * mask from before the sigsuspend is what we want 2000 * restored after the signal processing is completed. 2001 */ 2002 if (lp->lwp_flag & LWP_OLDMASK) { 2003 returnmask = lp->lwp_oldsigmask; 2004 lp->lwp_flag &= ~LWP_OLDMASK; 2005 } else { 2006 returnmask = lp->lwp_sigmask; 2007 } 2008 2009 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2010 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2011 SIGADDSET(lp->lwp_sigmask, sig); 2012 2013 crit_exit(); 2014 lp->lwp_ru.ru_nsignals++; 2015 if (lp->lwp_sig != sig) { 2016 code = 0; 2017 } else { 2018 code = lp->lwp_code; 2019 lp->lwp_code = 0; 2020 lp->lwp_sig = 0; 2021 } 2022 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2023 } 2024 done: 2025 ; 2026 } 2027 2028 /* 2029 * Kill the current process for stated reason. 2030 */ 2031 void 2032 killproc(struct proc *p, char *why) 2033 { 2034 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2035 p->p_pid, p->p_comm, 2036 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2037 ksignal(p, SIGKILL); 2038 } 2039 2040 /* 2041 * Force the current process to exit with the specified signal, dumping core 2042 * if appropriate. We bypass the normal tests for masked and caught signals, 2043 * allowing unrecoverable failures to terminate the process without changing 2044 * signal state. Mark the accounting record with the signal termination. 2045 * If dumping core, save the signal number for the debugger. Calls exit and 2046 * does not return. 2047 * 2048 * This routine does not return. 2049 */ 2050 void 2051 sigexit(struct lwp *lp, int sig) 2052 { 2053 struct proc *p = lp->lwp_proc; 2054 2055 lwkt_gettoken(&p->p_token); 2056 p->p_acflag |= AXSIG; 2057 if (sigprop(sig) & SA_CORE) { 2058 lp->lwp_sig = sig; 2059 /* 2060 * Log signals which would cause core dumps 2061 * (Log as LOG_INFO to appease those who don't want 2062 * these messages.) 2063 * XXX : Todo, as well as euid, write out ruid too 2064 */ 2065 if (coredump(lp, sig) == 0) 2066 sig |= WCOREFLAG; 2067 if (kern_logsigexit) 2068 log(LOG_INFO, 2069 "pid %d (%s), uid %d: exited on signal %d%s\n", 2070 p->p_pid, p->p_comm, 2071 p->p_ucred ? p->p_ucred->cr_uid : -1, 2072 sig &~ WCOREFLAG, 2073 sig & WCOREFLAG ? " (core dumped)" : ""); 2074 } 2075 lwkt_reltoken(&p->p_token); 2076 exit1(W_EXITCODE(0, sig)); 2077 /* NOTREACHED */ 2078 } 2079 2080 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2081 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2082 sizeof(corefilename), "process corefile name format string"); 2083 2084 /* 2085 * expand_name(name, uid, pid) 2086 * Expand the name described in corefilename, using name, uid, and pid. 2087 * corefilename is a kprintf-like string, with three format specifiers: 2088 * %N name of process ("name") 2089 * %P process id (pid) 2090 * %U user id (uid) 2091 * For example, "%N.core" is the default; they can be disabled completely 2092 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2093 * This is controlled by the sysctl variable kern.corefile (see above). 2094 */ 2095 2096 static char * 2097 expand_name(const char *name, uid_t uid, pid_t pid) 2098 { 2099 char *temp; 2100 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2101 int i, n; 2102 char *format = corefilename; 2103 size_t namelen; 2104 2105 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2106 if (temp == NULL) 2107 return NULL; 2108 namelen = strlen(name); 2109 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2110 int l; 2111 switch (format[i]) { 2112 case '%': /* Format character */ 2113 i++; 2114 switch (format[i]) { 2115 case '%': 2116 temp[n++] = '%'; 2117 break; 2118 case 'N': /* process name */ 2119 if ((n + namelen) > MAXPATHLEN) { 2120 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2121 pid, name, uid, temp, name); 2122 kfree(temp, M_TEMP); 2123 return NULL; 2124 } 2125 memcpy(temp+n, name, namelen); 2126 n += namelen; 2127 break; 2128 case 'P': /* process id */ 2129 l = ksprintf(buf, "%u", pid); 2130 if ((n + l) > MAXPATHLEN) { 2131 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2132 pid, name, uid, temp, name); 2133 kfree(temp, M_TEMP); 2134 return NULL; 2135 } 2136 memcpy(temp+n, buf, l); 2137 n += l; 2138 break; 2139 case 'U': /* user id */ 2140 l = ksprintf(buf, "%u", uid); 2141 if ((n + l) > MAXPATHLEN) { 2142 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2143 pid, name, uid, temp, name); 2144 kfree(temp, M_TEMP); 2145 return NULL; 2146 } 2147 memcpy(temp+n, buf, l); 2148 n += l; 2149 break; 2150 default: 2151 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2152 } 2153 break; 2154 default: 2155 temp[n++] = format[i]; 2156 } 2157 } 2158 temp[n] = '\0'; 2159 return temp; 2160 } 2161 2162 /* 2163 * Dump a process' core. The main routine does some 2164 * policy checking, and creates the name of the coredump; 2165 * then it passes on a vnode and a size limit to the process-specific 2166 * coredump routine if there is one; if there _is not_ one, it returns 2167 * ENOSYS; otherwise it returns the error from the process-specific routine. 2168 * 2169 * The parameter `lp' is the lwp which triggered the coredump. 2170 */ 2171 2172 static int 2173 coredump(struct lwp *lp, int sig) 2174 { 2175 struct proc *p = lp->lwp_proc; 2176 struct vnode *vp; 2177 struct ucred *cred = p->p_ucred; 2178 struct flock lf; 2179 struct nlookupdata nd; 2180 struct vattr vattr; 2181 int error, error1; 2182 char *name; /* name of corefile */ 2183 off_t limit; 2184 2185 STOPEVENT(p, S_CORE, 0); 2186 2187 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2188 return (EFAULT); 2189 2190 /* 2191 * Note that the bulk of limit checking is done after 2192 * the corefile is created. The exception is if the limit 2193 * for corefiles is 0, in which case we don't bother 2194 * creating the corefile at all. This layout means that 2195 * a corefile is truncated instead of not being created, 2196 * if it is larger than the limit. 2197 */ 2198 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2199 if (limit == 0) 2200 return EFBIG; 2201 2202 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2203 if (name == NULL) 2204 return (EINVAL); 2205 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2206 if (error == 0) 2207 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2208 kfree(name, M_TEMP); 2209 if (error) { 2210 nlookup_done(&nd); 2211 return (error); 2212 } 2213 vp = nd.nl_open_vp; 2214 nd.nl_open_vp = NULL; 2215 nlookup_done(&nd); 2216 2217 vn_unlock(vp); 2218 lf.l_whence = SEEK_SET; 2219 lf.l_start = 0; 2220 lf.l_len = 0; 2221 lf.l_type = F_WRLCK; 2222 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2223 if (error) 2224 goto out2; 2225 2226 /* Don't dump to non-regular files or files with links. */ 2227 if (vp->v_type != VREG || 2228 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2229 error = EFAULT; 2230 goto out1; 2231 } 2232 2233 /* Don't dump to files current user does not own */ 2234 if (vattr.va_uid != p->p_ucred->cr_uid) { 2235 error = EFAULT; 2236 goto out1; 2237 } 2238 2239 VATTR_NULL(&vattr); 2240 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2241 vattr.va_size = 0; 2242 VOP_SETATTR(vp, &vattr, cred); 2243 p->p_acflag |= ACORE; 2244 vn_unlock(vp); 2245 2246 error = p->p_sysent->sv_coredump ? 2247 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2248 2249 out1: 2250 lf.l_type = F_UNLCK; 2251 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2252 out2: 2253 error1 = vn_close(vp, FWRITE); 2254 if (error == 0) 2255 error = error1; 2256 return (error); 2257 } 2258 2259 /* 2260 * Nonexistent system call-- signal process (may want to handle it). 2261 * Flag error in case process won't see signal immediately (blocked or ignored). 2262 * 2263 * MPALMOSTSAFE 2264 */ 2265 /* ARGSUSED */ 2266 int 2267 sys_nosys(struct nosys_args *args) 2268 { 2269 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2270 return (EINVAL); 2271 } 2272 2273 /* 2274 * Send a SIGIO or SIGURG signal to a process or process group using 2275 * stored credentials rather than those of the current process. 2276 */ 2277 void 2278 pgsigio(struct sigio *sigio, int sig, int checkctty) 2279 { 2280 if (sigio == NULL) 2281 return; 2282 2283 if (sigio->sio_pgid > 0) { 2284 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2285 sigio->sio_proc)) 2286 ksignal(sigio->sio_proc, sig); 2287 } else if (sigio->sio_pgid < 0) { 2288 struct proc *p; 2289 struct pgrp *pg = sigio->sio_pgrp; 2290 2291 /* 2292 * Must interlock all signals against fork 2293 */ 2294 pgref(pg); 2295 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2296 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2297 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2298 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2299 ksignal(p, sig); 2300 } 2301 lockmgr(&pg->pg_lock, LK_RELEASE); 2302 pgrel(pg); 2303 } 2304 } 2305 2306 static int 2307 filt_sigattach(struct knote *kn) 2308 { 2309 struct proc *p = curproc; 2310 2311 kn->kn_ptr.p_proc = p; 2312 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2313 2314 /* XXX lock the proc here while adding to the list? */ 2315 knote_insert(&p->p_klist, kn); 2316 2317 return (0); 2318 } 2319 2320 static void 2321 filt_sigdetach(struct knote *kn) 2322 { 2323 struct proc *p = kn->kn_ptr.p_proc; 2324 2325 knote_remove(&p->p_klist, kn); 2326 } 2327 2328 /* 2329 * signal knotes are shared with proc knotes, so we apply a mask to 2330 * the hint in order to differentiate them from process hints. This 2331 * could be avoided by using a signal-specific knote list, but probably 2332 * isn't worth the trouble. 2333 */ 2334 static int 2335 filt_signal(struct knote *kn, long hint) 2336 { 2337 if (hint & NOTE_SIGNAL) { 2338 hint &= ~NOTE_SIGNAL; 2339 2340 if (kn->kn_id == hint) 2341 kn->kn_data++; 2342 } 2343 return (kn->kn_data != 0); 2344 } 2345