1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 40 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/sysproto.h> 48 #include <sys/signalvar.h> 49 #include <sys/resourcevar.h> 50 #include <sys/vnode.h> 51 #include <sys/event.h> 52 #include <sys/proc.h> 53 #include <sys/nlookup.h> 54 #include <sys/pioctl.h> 55 #include <sys/acct.h> 56 #include <sys/fcntl.h> 57 #include <sys/lock.h> 58 #include <sys/wait.h> 59 #include <sys/ktrace.h> 60 #include <sys/syslog.h> 61 #include <sys/stat.h> 62 #include <sys/sysent.h> 63 #include <sys/sysctl.h> 64 #include <sys/malloc.h> 65 #include <sys/interrupt.h> 66 #include <sys/unistd.h> 67 #include <sys/kern_syscall.h> 68 #include <sys/vkernel.h> 69 70 #include <sys/signal2.h> 71 #include <sys/thread2.h> 72 73 #include <machine/cpu.h> 74 #include <machine/smp.h> 75 76 static int coredump(struct lwp *, int); 77 static char *expand_name(const char *, uid_t, pid_t); 78 static int dokillpg(int sig, int pgid, int all); 79 static int sig_ffs(sigset_t *set); 80 static int sigprop(int sig); 81 static void lwp_signotify(struct lwp *lp); 82 #ifdef SMP 83 static void signotify_remote(void *arg); 84 #endif 85 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 86 struct timespec *timeout); 87 88 static int filt_sigattach(struct knote *kn); 89 static void filt_sigdetach(struct knote *kn); 90 static int filt_signal(struct knote *kn, long hint); 91 92 struct filterops sig_filtops = 93 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 94 95 static int kern_logsigexit = 1; 96 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 97 &kern_logsigexit, 0, 98 "Log processes quitting on abnormal signals to syslog(3)"); 99 100 /* 101 * Can process p, with pcred pc, send the signal sig to process q? 102 */ 103 #define CANSIGNAL(q, sig) \ 104 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 105 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 106 107 /* 108 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 109 */ 110 #define CANSIGIO(ruid, uc, q) \ 111 ((uc)->cr_uid == 0 || \ 112 (ruid) == (q)->p_ucred->cr_ruid || \ 113 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 114 (ruid) == (q)->p_ucred->cr_uid || \ 115 (uc)->cr_uid == (q)->p_ucred->cr_uid) 116 117 int sugid_coredump; 118 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 119 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 120 121 static int do_coredump = 1; 122 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 123 &do_coredump, 0, "Enable/Disable coredumps"); 124 125 /* 126 * Signal properties and actions. 127 * The array below categorizes the signals and their default actions 128 * according to the following properties: 129 */ 130 #define SA_KILL 0x01 /* terminates process by default */ 131 #define SA_CORE 0x02 /* ditto and coredumps */ 132 #define SA_STOP 0x04 /* suspend process */ 133 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 134 #define SA_IGNORE 0x10 /* ignore by default */ 135 #define SA_CONT 0x20 /* continue if suspended */ 136 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 137 #define SA_CKPT 0x80 /* checkpoint process */ 138 139 140 static int sigproptbl[NSIG] = { 141 SA_KILL, /* SIGHUP */ 142 SA_KILL, /* SIGINT */ 143 SA_KILL|SA_CORE, /* SIGQUIT */ 144 SA_KILL|SA_CORE, /* SIGILL */ 145 SA_KILL|SA_CORE, /* SIGTRAP */ 146 SA_KILL|SA_CORE, /* SIGABRT */ 147 SA_KILL|SA_CORE, /* SIGEMT */ 148 SA_KILL|SA_CORE, /* SIGFPE */ 149 SA_KILL, /* SIGKILL */ 150 SA_KILL|SA_CORE, /* SIGBUS */ 151 SA_KILL|SA_CORE, /* SIGSEGV */ 152 SA_KILL|SA_CORE, /* SIGSYS */ 153 SA_KILL, /* SIGPIPE */ 154 SA_KILL, /* SIGALRM */ 155 SA_KILL, /* SIGTERM */ 156 SA_IGNORE, /* SIGURG */ 157 SA_STOP, /* SIGSTOP */ 158 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 159 SA_IGNORE|SA_CONT, /* SIGCONT */ 160 SA_IGNORE, /* SIGCHLD */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 162 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 163 SA_IGNORE, /* SIGIO */ 164 SA_KILL, /* SIGXCPU */ 165 SA_KILL, /* SIGXFSZ */ 166 SA_KILL, /* SIGVTALRM */ 167 SA_KILL, /* SIGPROF */ 168 SA_IGNORE, /* SIGWINCH */ 169 SA_IGNORE, /* SIGINFO */ 170 SA_KILL, /* SIGUSR1 */ 171 SA_KILL, /* SIGUSR2 */ 172 SA_IGNORE, /* SIGTHR */ 173 SA_CKPT, /* SIGCKPT */ 174 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 SA_IGNORE, 205 206 }; 207 208 static __inline int 209 sigprop(int sig) 210 { 211 212 if (sig > 0 && sig < NSIG) 213 return (sigproptbl[_SIG_IDX(sig)]); 214 return (0); 215 } 216 217 static __inline int 218 sig_ffs(sigset_t *set) 219 { 220 int i; 221 222 for (i = 0; i < _SIG_WORDS; i++) 223 if (set->__bits[i]) 224 return (ffs(set->__bits[i]) + (i * 32)); 225 return (0); 226 } 227 228 /* 229 * No requirements. 230 */ 231 int 232 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 233 { 234 struct thread *td = curthread; 235 struct proc *p = td->td_proc; 236 struct lwp *lp; 237 struct sigacts *ps = p->p_sigacts; 238 239 if (sig <= 0 || sig > _SIG_MAXSIG) 240 return (EINVAL); 241 242 lwkt_gettoken(&p->p_token); 243 244 if (oact) { 245 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 246 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 247 oact->sa_flags = 0; 248 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 249 oact->sa_flags |= SA_ONSTACK; 250 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 251 oact->sa_flags |= SA_RESTART; 252 if (SIGISMEMBER(ps->ps_sigreset, sig)) 253 oact->sa_flags |= SA_RESETHAND; 254 if (SIGISMEMBER(ps->ps_signodefer, sig)) 255 oact->sa_flags |= SA_NODEFER; 256 if (SIGISMEMBER(ps->ps_siginfo, sig)) 257 oact->sa_flags |= SA_SIGINFO; 258 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 259 oact->sa_flags |= SA_MAILBOX; 260 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 261 oact->sa_flags |= SA_NOCLDSTOP; 262 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 263 oact->sa_flags |= SA_NOCLDWAIT; 264 } 265 if (act) { 266 /* 267 * Check for invalid requests. KILL and STOP cannot be 268 * caught. 269 */ 270 if (sig == SIGKILL || sig == SIGSTOP) { 271 if (act->sa_handler != SIG_DFL) { 272 lwkt_reltoken(&p->p_token); 273 return (EINVAL); 274 } 275 #if 0 276 /* (not needed, SIG_DFL forces action to occur) */ 277 if (act->sa_flags & SA_MAILBOX) { 278 lwkt_reltoken(&p->p_token); 279 return (EINVAL); 280 } 281 #endif 282 } 283 284 /* 285 * Change setting atomically. 286 */ 287 crit_enter(); 288 289 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 290 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 291 if (act->sa_flags & SA_SIGINFO) { 292 ps->ps_sigact[_SIG_IDX(sig)] = 293 (__sighandler_t *)act->sa_sigaction; 294 SIGADDSET(ps->ps_siginfo, sig); 295 } else { 296 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 297 SIGDELSET(ps->ps_siginfo, sig); 298 } 299 if (!(act->sa_flags & SA_RESTART)) 300 SIGADDSET(ps->ps_sigintr, sig); 301 else 302 SIGDELSET(ps->ps_sigintr, sig); 303 if (act->sa_flags & SA_ONSTACK) 304 SIGADDSET(ps->ps_sigonstack, sig); 305 else 306 SIGDELSET(ps->ps_sigonstack, sig); 307 if (act->sa_flags & SA_RESETHAND) 308 SIGADDSET(ps->ps_sigreset, sig); 309 else 310 SIGDELSET(ps->ps_sigreset, sig); 311 if (act->sa_flags & SA_NODEFER) 312 SIGADDSET(ps->ps_signodefer, sig); 313 else 314 SIGDELSET(ps->ps_signodefer, sig); 315 if (act->sa_flags & SA_MAILBOX) 316 SIGADDSET(ps->ps_sigmailbox, sig); 317 else 318 SIGDELSET(ps->ps_sigmailbox, sig); 319 if (sig == SIGCHLD) { 320 if (act->sa_flags & SA_NOCLDSTOP) 321 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 322 else 323 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 324 if (act->sa_flags & SA_NOCLDWAIT) { 325 /* 326 * Paranoia: since SA_NOCLDWAIT is implemented 327 * by reparenting the dying child to PID 1 (and 328 * trust it to reap the zombie), PID 1 itself 329 * is forbidden to set SA_NOCLDWAIT. 330 */ 331 if (p->p_pid == 1) 332 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 333 else 334 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 335 } else { 336 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 337 } 338 } 339 /* 340 * Set bit in p_sigignore for signals that are set to SIG_IGN, 341 * and for signals set to SIG_DFL where the default is to 342 * ignore. However, don't put SIGCONT in p_sigignore, as we 343 * have to restart the process. 344 */ 345 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 346 (sigprop(sig) & SA_IGNORE && 347 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 348 /* never to be seen again */ 349 SIGDELSET(p->p_siglist, sig); 350 /* 351 * Remove the signal also from the thread lists. 352 */ 353 FOREACH_LWP_IN_PROC(lp, p) { 354 SIGDELSET(lp->lwp_siglist, sig); 355 } 356 if (sig != SIGCONT) { 357 /* easier in ksignal */ 358 SIGADDSET(p->p_sigignore, sig); 359 } 360 SIGDELSET(p->p_sigcatch, sig); 361 } else { 362 SIGDELSET(p->p_sigignore, sig); 363 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 364 SIGDELSET(p->p_sigcatch, sig); 365 else 366 SIGADDSET(p->p_sigcatch, sig); 367 } 368 369 crit_exit(); 370 } 371 lwkt_reltoken(&p->p_token); 372 return (0); 373 } 374 375 int 376 sys_sigaction(struct sigaction_args *uap) 377 { 378 struct sigaction act, oact; 379 struct sigaction *actp, *oactp; 380 int error; 381 382 actp = (uap->act != NULL) ? &act : NULL; 383 oactp = (uap->oact != NULL) ? &oact : NULL; 384 if (actp) { 385 error = copyin(uap->act, actp, sizeof(act)); 386 if (error) 387 return (error); 388 } 389 error = kern_sigaction(uap->sig, actp, oactp); 390 if (oactp && !error) { 391 error = copyout(oactp, uap->oact, sizeof(oact)); 392 } 393 return (error); 394 } 395 396 /* 397 * Initialize signal state for process 0; 398 * set to ignore signals that are ignored by default. 399 */ 400 void 401 siginit(struct proc *p) 402 { 403 int i; 404 405 for (i = 1; i <= NSIG; i++) 406 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 407 SIGADDSET(p->p_sigignore, i); 408 } 409 410 /* 411 * Reset signals for an exec of the specified process. 412 */ 413 void 414 execsigs(struct proc *p) 415 { 416 struct sigacts *ps = p->p_sigacts; 417 struct lwp *lp; 418 int sig; 419 420 lp = ONLY_LWP_IN_PROC(p); 421 422 /* 423 * Reset caught signals. Held signals remain held 424 * through p_sigmask (unless they were caught, 425 * and are now ignored by default). 426 */ 427 while (SIGNOTEMPTY(p->p_sigcatch)) { 428 sig = sig_ffs(&p->p_sigcatch); 429 SIGDELSET(p->p_sigcatch, sig); 430 if (sigprop(sig) & SA_IGNORE) { 431 if (sig != SIGCONT) 432 SIGADDSET(p->p_sigignore, sig); 433 SIGDELSET(p->p_siglist, sig); 434 SIGDELSET(lp->lwp_siglist, sig); 435 } 436 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 437 } 438 439 /* 440 * Reset stack state to the user stack. 441 * Clear set of signals caught on the signal stack. 442 */ 443 lp->lwp_sigstk.ss_flags = SS_DISABLE; 444 lp->lwp_sigstk.ss_size = 0; 445 lp->lwp_sigstk.ss_sp = 0; 446 lp->lwp_flag &= ~LWP_ALTSTACK; 447 /* 448 * Reset no zombies if child dies flag as Solaris does. 449 */ 450 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 451 } 452 453 /* 454 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 455 * 456 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 457 * p == curproc. 458 */ 459 int 460 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 461 { 462 struct thread *td = curthread; 463 struct lwp *lp = td->td_lwp; 464 struct proc *p = td->td_proc; 465 int error; 466 467 lwkt_gettoken(&p->p_token); 468 469 if (oset != NULL) 470 *oset = lp->lwp_sigmask; 471 472 error = 0; 473 if (set != NULL) { 474 switch (how) { 475 case SIG_BLOCK: 476 SIG_CANTMASK(*set); 477 SIGSETOR(lp->lwp_sigmask, *set); 478 break; 479 case SIG_UNBLOCK: 480 SIGSETNAND(lp->lwp_sigmask, *set); 481 break; 482 case SIG_SETMASK: 483 SIG_CANTMASK(*set); 484 lp->lwp_sigmask = *set; 485 break; 486 default: 487 error = EINVAL; 488 break; 489 } 490 } 491 492 lwkt_reltoken(&p->p_token); 493 494 return (error); 495 } 496 497 /* 498 * sigprocmask() 499 * 500 * MPSAFE 501 */ 502 int 503 sys_sigprocmask(struct sigprocmask_args *uap) 504 { 505 sigset_t set, oset; 506 sigset_t *setp, *osetp; 507 int error; 508 509 setp = (uap->set != NULL) ? &set : NULL; 510 osetp = (uap->oset != NULL) ? &oset : NULL; 511 if (setp) { 512 error = copyin(uap->set, setp, sizeof(set)); 513 if (error) 514 return (error); 515 } 516 error = kern_sigprocmask(uap->how, setp, osetp); 517 if (osetp && !error) { 518 error = copyout(osetp, uap->oset, sizeof(oset)); 519 } 520 return (error); 521 } 522 523 /* 524 * MPSAFE 525 */ 526 int 527 kern_sigpending(struct __sigset *set) 528 { 529 struct lwp *lp = curthread->td_lwp; 530 531 *set = lwp_sigpend(lp); 532 533 return (0); 534 } 535 536 /* 537 * MPSAFE 538 */ 539 int 540 sys_sigpending(struct sigpending_args *uap) 541 { 542 sigset_t set; 543 int error; 544 545 error = kern_sigpending(&set); 546 547 if (error == 0) 548 error = copyout(&set, uap->set, sizeof(set)); 549 return (error); 550 } 551 552 /* 553 * Suspend process until signal, providing mask to be set 554 * in the meantime. 555 * 556 * MPSAFE 557 */ 558 int 559 kern_sigsuspend(struct __sigset *set) 560 { 561 struct thread *td = curthread; 562 struct lwp *lp = td->td_lwp; 563 struct proc *p = td->td_proc; 564 struct sigacts *ps = p->p_sigacts; 565 566 /* 567 * When returning from sigsuspend, we want 568 * the old mask to be restored after the 569 * signal handler has finished. Thus, we 570 * save it here and mark the sigacts structure 571 * to indicate this. 572 */ 573 lp->lwp_oldsigmask = lp->lwp_sigmask; 574 lp->lwp_flag |= LWP_OLDMASK; 575 576 SIG_CANTMASK(*set); 577 lp->lwp_sigmask = *set; 578 while (tsleep(ps, PCATCH, "pause", 0) == 0) 579 /* void */; 580 /* always return EINTR rather than ERESTART... */ 581 return (EINTR); 582 } 583 584 /* 585 * Note nonstandard calling convention: libc stub passes mask, not 586 * pointer, to save a copyin. 587 * 588 * MPSAFE 589 */ 590 int 591 sys_sigsuspend(struct sigsuspend_args *uap) 592 { 593 sigset_t mask; 594 int error; 595 596 error = copyin(uap->sigmask, &mask, sizeof(mask)); 597 if (error) 598 return (error); 599 600 error = kern_sigsuspend(&mask); 601 602 return (error); 603 } 604 605 /* 606 * MPSAFE 607 */ 608 int 609 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 610 { 611 struct thread *td = curthread; 612 struct lwp *lp = td->td_lwp; 613 struct proc *p = td->td_proc; 614 615 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 616 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 617 618 if (oss) 619 *oss = lp->lwp_sigstk; 620 621 if (ss) { 622 if (ss->ss_flags & SS_DISABLE) { 623 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 624 return (EINVAL); 625 lp->lwp_flag &= ~LWP_ALTSTACK; 626 lp->lwp_sigstk.ss_flags = ss->ss_flags; 627 } else { 628 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 629 return (ENOMEM); 630 lp->lwp_flag |= LWP_ALTSTACK; 631 lp->lwp_sigstk = *ss; 632 } 633 } 634 635 return (0); 636 } 637 638 /* 639 * MPSAFE 640 */ 641 int 642 sys_sigaltstack(struct sigaltstack_args *uap) 643 { 644 stack_t ss, oss; 645 int error; 646 647 if (uap->ss) { 648 error = copyin(uap->ss, &ss, sizeof(ss)); 649 if (error) 650 return (error); 651 } 652 653 error = kern_sigaltstack(uap->ss ? &ss : NULL, 654 uap->oss ? &oss : NULL); 655 656 if (error == 0 && uap->oss) 657 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 658 return (error); 659 } 660 661 /* 662 * Common code for kill process group/broadcast kill. 663 * cp is calling process. 664 */ 665 struct killpg_info { 666 int nfound; 667 int sig; 668 }; 669 670 static int killpg_all_callback(struct proc *p, void *data); 671 672 static int 673 dokillpg(int sig, int pgid, int all) 674 { 675 struct killpg_info info; 676 struct proc *cp = curproc; 677 struct proc *p; 678 struct pgrp *pgrp; 679 680 info.nfound = 0; 681 info.sig = sig; 682 683 if (all) { 684 /* 685 * broadcast 686 */ 687 allproc_scan(killpg_all_callback, &info); 688 } else { 689 if (pgid == 0) { 690 /* 691 * zero pgid means send to my process group. 692 */ 693 pgrp = cp->p_pgrp; 694 pgref(pgrp); 695 } else { 696 pgrp = pgfind(pgid); 697 if (pgrp == NULL) 698 return (ESRCH); 699 } 700 701 /* 702 * Must interlock all signals against fork 703 */ 704 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 705 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 706 if (p->p_pid <= 1 || 707 p->p_stat == SZOMB || 708 (p->p_flag & P_SYSTEM) || 709 !CANSIGNAL(p, sig)) { 710 continue; 711 } 712 ++info.nfound; 713 if (sig) 714 ksignal(p, sig); 715 } 716 lockmgr(&pgrp->pg_lock, LK_RELEASE); 717 pgrel(pgrp); 718 } 719 return (info.nfound ? 0 : ESRCH); 720 } 721 722 static int 723 killpg_all_callback(struct proc *p, void *data) 724 { 725 struct killpg_info *info = data; 726 727 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 728 p == curproc || !CANSIGNAL(p, info->sig)) { 729 return (0); 730 } 731 ++info->nfound; 732 if (info->sig) 733 ksignal(p, info->sig); 734 return(0); 735 } 736 737 /* 738 * Send a general signal to a process or LWPs within that process. Note 739 * that new signals cannot be sent if a process is exiting. 740 * 741 * No requirements. 742 */ 743 int 744 kern_kill(int sig, pid_t pid, lwpid_t tid) 745 { 746 int t; 747 748 if ((u_int)sig > _SIG_MAXSIG) 749 return (EINVAL); 750 751 lwkt_gettoken(&proc_token); 752 753 if (pid > 0) { 754 struct proc *p; 755 struct lwp *lp = NULL; 756 757 /* kill single process */ 758 if ((p = pfind(pid)) == NULL) { 759 lwkt_reltoken(&proc_token); 760 return (ESRCH); 761 } 762 lwkt_gettoken(&p->p_token); 763 if (!CANSIGNAL(p, sig)) { 764 lwkt_reltoken(&p->p_token); 765 PRELE(p); 766 lwkt_reltoken(&proc_token); 767 return (EPERM); 768 } 769 770 /* 771 * NOP if the process is exiting. Note that lwpsignal() is 772 * called directly with P_WEXIT set to kill individual LWPs 773 * during exit, which is allowed. 774 */ 775 if (p->p_flag & P_WEXIT) { 776 lwkt_reltoken(&p->p_token); 777 PRELE(p); 778 lwkt_reltoken(&proc_token); 779 return (0); 780 } 781 if (tid != -1) { 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 lwkt_reltoken(&proc_token); 787 return (ESRCH); 788 } 789 } 790 if (sig) 791 lwpsignal(p, lp, sig); 792 lwkt_reltoken(&p->p_token); 793 PRELE(p); 794 lwkt_reltoken(&proc_token); 795 return (0); 796 } 797 798 /* 799 * If we come here, pid is a special broadcast pid. 800 * This doesn't mix with a tid. 801 */ 802 if (tid != -1) { 803 lwkt_reltoken(&proc_token); 804 return (EINVAL); 805 } 806 switch (pid) { 807 case -1: /* broadcast signal */ 808 t = (dokillpg(sig, 0, 1)); 809 break; 810 case 0: /* signal own process group */ 811 t = (dokillpg(sig, 0, 0)); 812 break; 813 default: /* negative explicit process group */ 814 t = (dokillpg(sig, -pid, 0)); 815 break; 816 } 817 lwkt_reltoken(&proc_token); 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_flag & 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 } 916 917 918 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 919 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 920 lp->lwp_ru.ru_nsignals++; 921 #ifdef KTRACE 922 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 923 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 924 &lp->lwp_sigmask, code); 925 #endif 926 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 927 &lp->lwp_sigmask, code); 928 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 929 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 930 SIGADDSET(lp->lwp_sigmask, sig); 931 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 932 /* 933 * See kern_sigaction() for origin of this code. 934 */ 935 SIGDELSET(p->p_sigcatch, sig); 936 if (sig != SIGCONT && 937 sigprop(sig) & SA_IGNORE) 938 SIGADDSET(p->p_sigignore, sig); 939 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 940 } 941 } else { 942 lp->lwp_code = code; /* XXX for core dump/debugger */ 943 lp->lwp_sig = sig; /* XXX to verify code */ 944 lwpsignal(p, lp, sig); 945 } 946 } 947 948 /* 949 * Find a suitable lwp to deliver the signal to. Returns NULL if all 950 * lwps hold the signal blocked. 951 * 952 * Caller must hold p->p_token. 953 */ 954 static struct lwp * 955 find_lwp_for_signal(struct proc *p, int sig) 956 { 957 struct lwp *lp; 958 struct lwp *run, *sleep, *stop; 959 960 /* 961 * If the running/preempted thread belongs to the proc to which 962 * the signal is being delivered and this thread does not block 963 * the signal, then we can avoid a context switch by delivering 964 * the signal to this thread, because it will return to userland 965 * soon anyways. 966 */ 967 lp = lwkt_preempted_proc(); 968 if (lp != NULL && lp->lwp_proc == p && 969 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 970 return (lp); 971 } 972 973 run = sleep = stop = NULL; 974 FOREACH_LWP_IN_PROC(lp, p) { 975 /* 976 * If the signal is being blocked by the lwp, then this 977 * lwp is not eligible for receiving the signal. 978 */ 979 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 980 continue; 981 982 switch (lp->lwp_stat) { 983 case LSRUN: 984 run = lp; 985 break; 986 987 case LSSTOP: 988 stop = lp; 989 break; 990 991 case LSSLEEP: 992 if (lp->lwp_flag & LWP_SINTR) 993 sleep = lp; 994 break; 995 } 996 } 997 998 if (run != NULL) 999 return (run); 1000 else if (sleep != NULL) 1001 return (sleep); 1002 else 1003 return (stop); 1004 } 1005 1006 /* 1007 * Send the signal to the process. If the signal has an action, the action 1008 * is usually performed by the target process rather than the caller; we add 1009 * the signal to the set of pending signals for the process. 1010 * 1011 * Exceptions: 1012 * o When a stop signal is sent to a sleeping process that takes the 1013 * default action, the process is stopped without awakening it. 1014 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1015 * regardless of the signal action (eg, blocked or ignored). 1016 * 1017 * Other ignored signals are discarded immediately. 1018 * 1019 * If the caller wishes to call this function from a hard code section the 1020 * caller must already hold p->p_token (see kern_clock.c). 1021 * 1022 * No requirements. 1023 */ 1024 void 1025 ksignal(struct proc *p, int sig) 1026 { 1027 lwpsignal(p, NULL, sig); 1028 } 1029 1030 /* 1031 * The core for ksignal. lp may be NULL, then a suitable thread 1032 * will be chosen. If not, lp MUST be a member of p. 1033 * 1034 * If the caller wishes to call this function from a hard code section the 1035 * caller must already hold p->p_token. 1036 * 1037 * No requirements. 1038 */ 1039 void 1040 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1041 { 1042 struct proc *q; 1043 sig_t action; 1044 int prop; 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 /* 1084 * Even if a signal is set SIG_IGN, it may still be 1085 * lurking in a kqueue. 1086 */ 1087 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1088 lwkt_reltoken(&p->p_token); 1089 PRELE(p); 1090 return; 1091 } 1092 if (SIGISMEMBER(p->p_sigcatch, sig)) 1093 action = SIG_CATCH; 1094 else 1095 action = SIG_DFL; 1096 } 1097 1098 /* 1099 * If continuing, clear any pending STOP signals. 1100 */ 1101 if (prop & SA_CONT) 1102 SIG_STOPSIGMASK(p->p_siglist); 1103 1104 if (prop & SA_STOP) { 1105 /* 1106 * If sending a tty stop signal to a member of an orphaned 1107 * process group, discard the signal here if the action 1108 * is default; don't stop the process below if sleeping, 1109 * and don't clear any pending SIGCONT. 1110 */ 1111 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1112 action == SIG_DFL) { 1113 lwkt_reltoken(&p->p_token); 1114 PRELE(p); 1115 return; 1116 } 1117 SIG_CONTSIGMASK(p->p_siglist); 1118 p->p_flag &= ~P_CONTINUED; 1119 } 1120 1121 crit_enter(); 1122 1123 if (p->p_stat == SSTOP) { 1124 /* 1125 * Nobody can handle this signal, add it to the lwp or 1126 * process pending list 1127 */ 1128 if (lp) 1129 SIGADDSET(lp->lwp_siglist, sig); 1130 else 1131 SIGADDSET(p->p_siglist, sig); 1132 1133 /* 1134 * If the process is stopped and is being traced, then no 1135 * further action is necessary. 1136 */ 1137 if (p->p_flag & P_TRACED) 1138 goto out; 1139 1140 /* 1141 * If the process is stopped and receives a KILL signal, 1142 * make the process runnable. 1143 */ 1144 if (sig == SIGKILL) { 1145 proc_unstop(p); 1146 goto active_process; 1147 } 1148 1149 /* 1150 * If the process is stopped and receives a CONT signal, 1151 * then try to make the process runnable again. 1152 */ 1153 if (prop & SA_CONT) { 1154 /* 1155 * If SIGCONT is default (or ignored), we continue the 1156 * process but don't leave the signal in p_siglist, as 1157 * it has no further action. If SIGCONT is held, we 1158 * continue the process and leave the signal in 1159 * p_siglist. If the process catches SIGCONT, let it 1160 * handle the signal itself. 1161 * 1162 * XXX what if the signal is being held blocked? 1163 * 1164 * Token required to interlock kern_wait(). 1165 * Reparenting can also cause a race so we have to 1166 * hold (q). 1167 */ 1168 q = p->p_pptr; 1169 PHOLD(q); 1170 lwkt_gettoken(&q->p_token); 1171 p->p_flag |= P_CONTINUED; 1172 wakeup(q); 1173 if (action == SIG_DFL) 1174 SIGDELSET(p->p_siglist, sig); 1175 proc_unstop(p); 1176 lwkt_reltoken(&q->p_token); 1177 PRELE(q); 1178 if (action == SIG_CATCH) 1179 goto active_process; 1180 goto out; 1181 } 1182 1183 /* 1184 * If the process is stopped and receives another STOP 1185 * signal, we do not need to stop it again. If we did 1186 * the shell could get confused. 1187 * 1188 * However, if the current/preempted lwp is part of the 1189 * process receiving the signal, we need to keep it, 1190 * so that this lwp can stop in issignal() later, as 1191 * we don't want to wait until it reaches userret! 1192 */ 1193 if (prop & SA_STOP) { 1194 if (lwkt_preempted_proc() == NULL || 1195 lwkt_preempted_proc()->lwp_proc != p) 1196 SIGDELSET(p->p_siglist, sig); 1197 } 1198 1199 /* 1200 * Otherwise the process is stopped and it received some 1201 * signal, which does not change its stopped state. 1202 * 1203 * We have to select one thread to set LWP_BREAKTSLEEP, 1204 * so that the current signal will break the sleep 1205 * as soon as a SA_CONT signal will unstop the process. 1206 */ 1207 if (lp == NULL) 1208 lp = find_lwp_for_signal(p, sig); 1209 if (lp != NULL && 1210 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1211 lp->lwp_flag |= LWP_BREAKTSLEEP; 1212 goto out; 1213 1214 /* NOTREACHED */ 1215 } 1216 /* else not stopped */ 1217 active_process: 1218 1219 /* 1220 * Never deliver a lwp-specific signal to a random lwp. 1221 */ 1222 if (lp == NULL) { 1223 lp = find_lwp_for_signal(p, sig); 1224 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1225 lp = NULL; 1226 } 1227 1228 /* 1229 * Deliver to the process generically if (1) the signal is being 1230 * sent to any thread or (2) we could not find a thread to deliver 1231 * it to. 1232 */ 1233 if (lp == NULL) { 1234 SIGADDSET(p->p_siglist, sig); 1235 goto out; 1236 } 1237 1238 /* 1239 * Deliver to a specific LWP whether it masks it or not. It will 1240 * not be dispatched if masked but we must still deliver it. 1241 */ 1242 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1243 (p->p_flag & P_TRACED) == 0) { 1244 p->p_nice = NZERO; 1245 } 1246 1247 /* 1248 * If the process receives a STOP signal which indeed needs to 1249 * stop the process, do so. If the process chose to catch the 1250 * signal, it will be treated like any other signal. 1251 */ 1252 if ((prop & SA_STOP) && action == SIG_DFL) { 1253 /* 1254 * If a child holding parent blocked, stopping 1255 * could cause deadlock. Take no action at this 1256 * time. 1257 */ 1258 if (p->p_flag & P_PPWAIT) { 1259 SIGADDSET(p->p_siglist, sig); 1260 goto out; 1261 } 1262 1263 /* 1264 * Do not actually try to manipulate the process, but simply 1265 * stop it. Lwps will stop as soon as they safely can. 1266 */ 1267 p->p_xstat = sig; 1268 proc_stop(p); 1269 goto out; 1270 } 1271 1272 /* 1273 * If it is a CONT signal with default action, just ignore it. 1274 */ 1275 if ((prop & SA_CONT) && action == SIG_DFL) 1276 goto out; 1277 1278 /* 1279 * Mark signal pending at this specific thread. 1280 */ 1281 SIGADDSET(lp->lwp_siglist, sig); 1282 1283 lwp_signotify(lp); 1284 1285 out: 1286 lwkt_reltoken(&p->p_token); 1287 PRELE(p); 1288 crit_exit(); 1289 } 1290 1291 /* 1292 * p->p_token must be held 1293 */ 1294 static void 1295 lwp_signotify(struct lwp *lp) 1296 { 1297 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1298 crit_enter(); 1299 1300 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1301 /* 1302 * Thread is in tsleep. 1303 */ 1304 1305 /* 1306 * If the thread is sleeping uninterruptibly 1307 * we can't interrupt the sleep... the signal will 1308 * be noticed when the lwp returns through 1309 * trap() or syscall(). 1310 * 1311 * Otherwise the signal can interrupt the sleep. 1312 * 1313 * If the process is traced, the lwp will handle the 1314 * tracing in issignal() when it returns to userland. 1315 */ 1316 if (lp->lwp_flag & LWP_SINTR) { 1317 /* 1318 * Make runnable and break out of any tsleep as well. 1319 */ 1320 lp->lwp_flag |= LWP_BREAKTSLEEP; 1321 setrunnable(lp); 1322 } 1323 } else { 1324 /* 1325 * Otherwise the thread is running 1326 * 1327 * LSRUN does nothing with the signal, other than kicking 1328 * ourselves if we are running. 1329 * SZOMB and SIDL mean that it will either never be noticed, 1330 * or noticed very soon. 1331 * 1332 * Note that lwp_thread may be NULL or may not be completely 1333 * initialized if the process is in the SIDL or SZOMB state. 1334 * 1335 * For SMP we may have to forward the request to another cpu. 1336 * YYY the MP lock prevents the target process from moving 1337 * to another cpu, see kern/kern_switch.c 1338 * 1339 * If the target thread is waiting on its message port, 1340 * wakeup the target thread so it can check (or ignore) 1341 * the new signal. YYY needs cleanup. 1342 */ 1343 if (lp == lwkt_preempted_proc()) { 1344 signotify(); 1345 } else if (lp->lwp_stat == LSRUN) { 1346 struct thread *td = lp->lwp_thread; 1347 struct proc *p __debugvar = lp->lwp_proc; 1348 1349 KASSERT(td != NULL, 1350 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1351 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1352 p->p_flag, lp->lwp_flag)); 1353 1354 /* 1355 * To prevent a MP race with TDF_SINTR we must 1356 * schedule the thread on the correct cpu. 1357 */ 1358 #ifdef SMP 1359 if (td->td_gd != mycpu) { 1360 LWPHOLD(lp); 1361 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1362 } else 1363 #endif 1364 if (td->td_flags & TDF_SINTR) 1365 lwkt_schedule(td); 1366 } 1367 } 1368 crit_exit(); 1369 } 1370 1371 #ifdef SMP 1372 1373 /* 1374 * This function is called via an IPI. We will be in a critical section but 1375 * the MP lock will NOT be held. The passed lp will be held. 1376 * 1377 * We must essentially repeat the code at the end of lwp_signotify(), 1378 * in particular rechecking all races. If we are still not on the 1379 * correct cpu we leave the lwp ref intact and continue the chase. 1380 * 1381 * XXX this may still not be entirely correct, since we are checking 1382 * lwp_stat asynchronously. 1383 */ 1384 static void 1385 signotify_remote(void *arg) 1386 { 1387 struct lwp *lp = arg; 1388 thread_t td; 1389 1390 if (lp == lwkt_preempted_proc()) { 1391 signotify(); 1392 } else if (lp->lwp_stat == LSRUN) { 1393 /* 1394 * To prevent a MP race with TDF_SINTR we must 1395 * schedule the thread on the correct cpu. 1396 */ 1397 td = lp->lwp_thread; 1398 if (td->td_gd != mycpu) { 1399 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1400 return; 1401 /* NOT REACHED */ 1402 } 1403 if (td->td_flags & TDF_SINTR) 1404 lwkt_schedule(td); 1405 } 1406 LWPRELE(lp); 1407 } 1408 1409 #endif 1410 1411 /* 1412 * Caller must hold p->p_token 1413 */ 1414 void 1415 proc_stop(struct proc *p) 1416 { 1417 struct proc *q; 1418 struct lwp *lp; 1419 1420 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1421 crit_enter(); 1422 1423 /* If somebody raced us, be happy with it */ 1424 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1425 crit_exit(); 1426 return; 1427 } 1428 p->p_stat = SSTOP; 1429 1430 FOREACH_LWP_IN_PROC(lp, p) { 1431 switch (lp->lwp_stat) { 1432 case LSSTOP: 1433 /* 1434 * Do nothing, we are already counted in 1435 * p_nstopped. 1436 */ 1437 break; 1438 1439 case LSSLEEP: 1440 /* 1441 * We're sleeping, but we will stop before 1442 * returning to userspace, so count us 1443 * as stopped as well. We set LWP_WSTOP 1444 * to signal the lwp that it should not 1445 * increase p_nstopped when reaching tstop(). 1446 */ 1447 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1448 lp->lwp_flag |= LWP_WSTOP; 1449 ++p->p_nstopped; 1450 } 1451 break; 1452 1453 case LSRUN: 1454 /* 1455 * We might notify ourself, but that's not 1456 * a problem. 1457 */ 1458 lwp_signotify(lp); 1459 break; 1460 } 1461 } 1462 1463 if (p->p_nstopped == p->p_nthreads) { 1464 /* 1465 * Token required to interlock kern_wait(). Reparenting can 1466 * also cause a race so we have to hold (q). 1467 */ 1468 q = p->p_pptr; 1469 PHOLD(q); 1470 lwkt_gettoken(&q->p_token); 1471 p->p_flag &= ~P_WAITED; 1472 wakeup(q); 1473 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1474 ksignal(p->p_pptr, SIGCHLD); 1475 lwkt_reltoken(&q->p_token); 1476 PRELE(q); 1477 } 1478 crit_exit(); 1479 } 1480 1481 /* 1482 * Caller must hold proc_token 1483 */ 1484 void 1485 proc_unstop(struct proc *p) 1486 { 1487 struct lwp *lp; 1488 1489 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1490 crit_enter(); 1491 1492 if (p->p_stat != SSTOP) { 1493 crit_exit(); 1494 return; 1495 } 1496 1497 p->p_stat = SACTIVE; 1498 1499 FOREACH_LWP_IN_PROC(lp, p) { 1500 switch (lp->lwp_stat) { 1501 case LSRUN: 1502 /* 1503 * Uh? Not stopped? Well, I guess that's okay. 1504 */ 1505 if (bootverbose) 1506 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1507 p->p_pid, lp->lwp_tid); 1508 break; 1509 1510 case LSSLEEP: 1511 /* 1512 * Still sleeping. Don't bother waking it up. 1513 * However, if this thread was counted as 1514 * stopped, undo this. 1515 * 1516 * Nevertheless we call setrunnable() so that it 1517 * will wake up in case a signal or timeout arrived 1518 * in the meantime. 1519 */ 1520 if (lp->lwp_flag & LWP_WSTOP) { 1521 lp->lwp_flag &= ~LWP_WSTOP; 1522 --p->p_nstopped; 1523 } else { 1524 if (bootverbose) 1525 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1526 p->p_pid, lp->lwp_tid); 1527 } 1528 /* FALLTHROUGH */ 1529 1530 case LSSTOP: 1531 setrunnable(lp); 1532 break; 1533 1534 } 1535 } 1536 crit_exit(); 1537 } 1538 1539 /* 1540 * No requirements. 1541 */ 1542 static int 1543 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1544 { 1545 sigset_t savedmask, set; 1546 struct proc *p = curproc; 1547 struct lwp *lp = curthread->td_lwp; 1548 int error, sig, hz, timevalid = 0; 1549 struct timespec rts, ets, ts; 1550 struct timeval tv; 1551 1552 error = 0; 1553 sig = 0; 1554 ets.tv_sec = 0; /* silence compiler warning */ 1555 ets.tv_nsec = 0; /* silence compiler warning */ 1556 SIG_CANTMASK(waitset); 1557 savedmask = lp->lwp_sigmask; 1558 1559 if (timeout) { 1560 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1561 timeout->tv_nsec < 1000000000) { 1562 timevalid = 1; 1563 getnanouptime(&rts); 1564 ets = rts; 1565 timespecadd(&ets, timeout); 1566 } 1567 } 1568 1569 for (;;) { 1570 set = lwp_sigpend(lp); 1571 SIGSETAND(set, waitset); 1572 if ((sig = sig_ffs(&set)) != 0) { 1573 SIGFILLSET(lp->lwp_sigmask); 1574 SIGDELSET(lp->lwp_sigmask, sig); 1575 SIG_CANTMASK(lp->lwp_sigmask); 1576 sig = issignal(lp, 1); 1577 /* 1578 * It may be a STOP signal, in the case, issignal 1579 * returns 0, because we may stop there, and new 1580 * signal can come in, we should restart if we got 1581 * nothing. 1582 */ 1583 if (sig == 0) 1584 continue; 1585 else 1586 break; 1587 } 1588 1589 /* 1590 * Previous checking got nothing, and we retried but still 1591 * got nothing, we should return the error status. 1592 */ 1593 if (error) 1594 break; 1595 1596 /* 1597 * POSIX says this must be checked after looking for pending 1598 * signals. 1599 */ 1600 if (timeout) { 1601 if (timevalid == 0) { 1602 error = EINVAL; 1603 break; 1604 } 1605 getnanouptime(&rts); 1606 if (timespeccmp(&rts, &ets, >=)) { 1607 error = EAGAIN; 1608 break; 1609 } 1610 ts = ets; 1611 timespecsub(&ts, &rts); 1612 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1613 hz = tvtohz_high(&tv); 1614 } else { 1615 hz = 0; 1616 } 1617 1618 lp->lwp_sigmask = savedmask; 1619 SIGSETNAND(lp->lwp_sigmask, waitset); 1620 /* 1621 * We won't ever be woken up. Instead, our sleep will 1622 * be broken in lwpsignal(). 1623 */ 1624 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1625 if (timeout) { 1626 if (error == ERESTART) { 1627 /* can not restart a timeout wait. */ 1628 error = EINTR; 1629 } else if (error == EAGAIN) { 1630 /* will calculate timeout by ourself. */ 1631 error = 0; 1632 } 1633 } 1634 /* Retry ... */ 1635 } 1636 1637 lp->lwp_sigmask = savedmask; 1638 if (sig) { 1639 error = 0; 1640 bzero(info, sizeof(*info)); 1641 info->si_signo = sig; 1642 lwp_delsig(lp, sig); /* take the signal! */ 1643 1644 if (sig == SIGKILL) { 1645 sigexit(lp, sig); 1646 /* NOT REACHED */ 1647 } 1648 } 1649 1650 return (error); 1651 } 1652 1653 /* 1654 * MPALMOSTSAFE 1655 */ 1656 int 1657 sys_sigtimedwait(struct sigtimedwait_args *uap) 1658 { 1659 struct timespec ts; 1660 struct timespec *timeout; 1661 sigset_t set; 1662 siginfo_t info; 1663 int error; 1664 1665 if (uap->timeout) { 1666 error = copyin(uap->timeout, &ts, sizeof(ts)); 1667 if (error) 1668 return (error); 1669 timeout = &ts; 1670 } else { 1671 timeout = NULL; 1672 } 1673 error = copyin(uap->set, &set, sizeof(set)); 1674 if (error) 1675 return (error); 1676 error = kern_sigtimedwait(set, &info, timeout); 1677 if (error) 1678 return (error); 1679 if (uap->info) 1680 error = copyout(&info, uap->info, sizeof(info)); 1681 /* Repost if we got an error. */ 1682 /* 1683 * XXX lwp 1684 * 1685 * This could transform a thread-specific signal to another 1686 * thread / process pending signal. 1687 */ 1688 if (error) { 1689 ksignal(curproc, info.si_signo); 1690 } else { 1691 uap->sysmsg_result = info.si_signo; 1692 } 1693 return (error); 1694 } 1695 1696 /* 1697 * MPALMOSTSAFE 1698 */ 1699 int 1700 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1701 { 1702 siginfo_t info; 1703 sigset_t set; 1704 int error; 1705 1706 error = copyin(uap->set, &set, sizeof(set)); 1707 if (error) 1708 return (error); 1709 error = kern_sigtimedwait(set, &info, NULL); 1710 if (error) 1711 return (error); 1712 if (uap->info) 1713 error = copyout(&info, uap->info, sizeof(info)); 1714 /* Repost if we got an error. */ 1715 /* 1716 * XXX lwp 1717 * 1718 * This could transform a thread-specific signal to another 1719 * thread / process pending signal. 1720 */ 1721 if (error) { 1722 ksignal(curproc, info.si_signo); 1723 } else { 1724 uap->sysmsg_result = info.si_signo; 1725 } 1726 return (error); 1727 } 1728 1729 /* 1730 * If the current process has received a signal that would interrupt a 1731 * system call, return EINTR or ERESTART as appropriate. 1732 */ 1733 int 1734 iscaught(struct lwp *lp) 1735 { 1736 struct proc *p = lp->lwp_proc; 1737 int sig; 1738 1739 if (p) { 1740 if ((sig = CURSIG(lp)) != 0) { 1741 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1742 return (EINTR); 1743 return (ERESTART); 1744 } 1745 } 1746 return(EWOULDBLOCK); 1747 } 1748 1749 /* 1750 * If the current process has received a signal (should be caught or cause 1751 * termination, should interrupt current syscall), return the signal number. 1752 * Stop signals with default action are processed immediately, then cleared; 1753 * they aren't returned. This is checked after each entry to the system for 1754 * a syscall or trap (though this can usually be done without calling issignal 1755 * by checking the pending signal masks in the CURSIG macro). 1756 * 1757 * This routine is called via CURSIG/__cursig. We will acquire and release 1758 * p->p_token but if the caller needs to interlock the test the caller must 1759 * also hold p->p_token. 1760 * 1761 * while (sig = CURSIG(curproc)) 1762 * postsig(sig); 1763 * 1764 * MPSAFE 1765 */ 1766 int 1767 issignal(struct lwp *lp, int maytrace) 1768 { 1769 struct proc *p = lp->lwp_proc; 1770 sigset_t mask; 1771 int sig, prop; 1772 1773 lwkt_gettoken(&p->p_token); 1774 1775 for (;;) { 1776 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1777 1778 /* 1779 * If this process is supposed to stop, stop this thread. 1780 */ 1781 if (p->p_stat == SSTOP) 1782 tstop(); 1783 1784 mask = lwp_sigpend(lp); 1785 SIGSETNAND(mask, lp->lwp_sigmask); 1786 if (p->p_flag & P_PPWAIT) 1787 SIG_STOPSIGMASK(mask); 1788 if (SIGISEMPTY(mask)) { /* no signal to send */ 1789 lwkt_reltoken(&p->p_token); 1790 return (0); 1791 } 1792 sig = sig_ffs(&mask); 1793 1794 STOPEVENT(p, S_SIG, sig); 1795 1796 /* 1797 * We should see pending but ignored signals 1798 * only if P_TRACED was on when they were posted. 1799 */ 1800 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1801 lwp_delsig(lp, sig); 1802 continue; 1803 } 1804 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1805 /* 1806 * If traced, always stop, and stay stopped until 1807 * released by the parent. 1808 * 1809 * NOTE: SSTOP may get cleared during the loop, 1810 * but we do not re-notify the parent if we have 1811 * to loop several times waiting for the parent 1812 * to let us continue. 1813 * 1814 * XXX not sure if this is still true 1815 */ 1816 p->p_xstat = sig; 1817 proc_stop(p); 1818 do { 1819 tstop(); 1820 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1821 1822 /* 1823 * If parent wants us to take the signal, 1824 * then it will leave it in p->p_xstat; 1825 * otherwise we just look for signals again. 1826 */ 1827 lwp_delsig(lp, sig); /* clear old signal */ 1828 sig = p->p_xstat; 1829 if (sig == 0) 1830 continue; 1831 1832 /* 1833 * Put the new signal into p_siglist. If the 1834 * signal is being masked, look for other signals. 1835 * 1836 * XXX lwp might need a call to ksignal() 1837 */ 1838 SIGADDSET(p->p_siglist, sig); 1839 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1840 continue; 1841 1842 /* 1843 * If the traced bit got turned off, go back up 1844 * to the top to rescan signals. This ensures 1845 * that p_sig* and ps_sigact are consistent. 1846 */ 1847 if ((p->p_flag & P_TRACED) == 0) 1848 continue; 1849 } 1850 1851 prop = sigprop(sig); 1852 1853 /* 1854 * Decide whether the signal should be returned. 1855 * Return the signal's number, or fall through 1856 * to clear it from the pending mask. 1857 */ 1858 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1859 case (intptr_t)SIG_DFL: 1860 /* 1861 * Don't take default actions on system processes. 1862 */ 1863 if (p->p_pid <= 1) { 1864 #ifdef DIAGNOSTIC 1865 /* 1866 * Are you sure you want to ignore SIGSEGV 1867 * in init? XXX 1868 */ 1869 kprintf("Process (pid %lu) got signal %d\n", 1870 (u_long)p->p_pid, sig); 1871 #endif 1872 break; /* == ignore */ 1873 } 1874 1875 /* 1876 * Handle the in-kernel checkpoint action 1877 */ 1878 if (prop & SA_CKPT) { 1879 checkpoint_signal_handler(lp); 1880 break; 1881 } 1882 1883 /* 1884 * If there is a pending stop signal to process 1885 * with default action, stop here, 1886 * then clear the signal. However, 1887 * if process is member of an orphaned 1888 * process group, ignore tty stop signals. 1889 */ 1890 if (prop & SA_STOP) { 1891 if (p->p_flag & P_TRACED || 1892 (p->p_pgrp->pg_jobc == 0 && 1893 prop & SA_TTYSTOP)) 1894 break; /* == ignore */ 1895 p->p_xstat = sig; 1896 proc_stop(p); 1897 tstop(); 1898 break; 1899 } else if (prop & SA_IGNORE) { 1900 /* 1901 * Except for SIGCONT, shouldn't get here. 1902 * Default action is to ignore; drop it. 1903 */ 1904 break; /* == ignore */ 1905 } else { 1906 lwkt_reltoken(&p->p_token); 1907 return (sig); 1908 } 1909 1910 /*NOTREACHED*/ 1911 1912 case (intptr_t)SIG_IGN: 1913 /* 1914 * Masking above should prevent us ever trying 1915 * to take action on an ignored signal other 1916 * than SIGCONT, unless process is traced. 1917 */ 1918 if ((prop & SA_CONT) == 0 && 1919 (p->p_flag & P_TRACED) == 0) 1920 kprintf("issignal\n"); 1921 break; /* == ignore */ 1922 1923 default: 1924 /* 1925 * This signal has an action, let 1926 * postsig() process it. 1927 */ 1928 lwkt_reltoken(&p->p_token); 1929 return (sig); 1930 } 1931 lwp_delsig(lp, sig); /* take the signal! */ 1932 } 1933 /* NOTREACHED */ 1934 } 1935 1936 /* 1937 * Take the action for the specified signal 1938 * from the current set of pending signals. 1939 * 1940 * Caller must hold p->p_token 1941 */ 1942 void 1943 postsig(int sig) 1944 { 1945 struct lwp *lp = curthread->td_lwp; 1946 struct proc *p = lp->lwp_proc; 1947 struct sigacts *ps = p->p_sigacts; 1948 sig_t action; 1949 sigset_t returnmask; 1950 int code; 1951 1952 KASSERT(sig != 0, ("postsig")); 1953 1954 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1955 1956 /* 1957 * If we are a virtual kernel running an emulated user process 1958 * context, switch back to the virtual kernel context before 1959 * trying to post the signal. 1960 */ 1961 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1962 struct trapframe *tf = lp->lwp_md.md_regs; 1963 tf->tf_trapno = 0; 1964 vkernel_trap(lp, tf); 1965 } 1966 1967 lwp_delsig(lp, sig); 1968 action = ps->ps_sigact[_SIG_IDX(sig)]; 1969 #ifdef KTRACE 1970 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1971 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1972 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1973 #endif 1974 STOPEVENT(p, S_SIG, sig); 1975 1976 if (action == SIG_DFL) { 1977 /* 1978 * Default action, where the default is to kill 1979 * the process. (Other cases were ignored above.) 1980 */ 1981 sigexit(lp, sig); 1982 /* NOTREACHED */ 1983 } else { 1984 /* 1985 * If we get here, the signal must be caught. 1986 */ 1987 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1988 ("postsig action")); 1989 1990 crit_enter(); 1991 1992 /* 1993 * Reset the signal handler if asked to 1994 */ 1995 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1996 /* 1997 * See kern_sigaction() for origin of this code. 1998 */ 1999 SIGDELSET(p->p_sigcatch, sig); 2000 if (sig != SIGCONT && 2001 sigprop(sig) & SA_IGNORE) 2002 SIGADDSET(p->p_sigignore, sig); 2003 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2004 } 2005 2006 /* 2007 * Handle the mailbox case. Copyout to the appropriate 2008 * location but do not generate a signal frame. The system 2009 * call simply returns EINTR and the user is responsible for 2010 * polling the mailbox. 2011 */ 2012 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 2013 int sig_copy = sig; 2014 copyout(&sig_copy, (void *)action, sizeof(int)); 2015 curproc->p_flag |= P_MAILBOX; 2016 crit_exit(); 2017 goto done; 2018 } 2019 2020 /* 2021 * Set the signal mask and calculate the mask to restore 2022 * when the signal function returns. 2023 * 2024 * Special case: user has done a sigsuspend. Here the 2025 * current mask is not of interest, but rather the 2026 * mask from before the sigsuspend is what we want 2027 * restored after the signal processing is completed. 2028 */ 2029 if (lp->lwp_flag & LWP_OLDMASK) { 2030 returnmask = lp->lwp_oldsigmask; 2031 lp->lwp_flag &= ~LWP_OLDMASK; 2032 } else { 2033 returnmask = lp->lwp_sigmask; 2034 } 2035 2036 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2037 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2038 SIGADDSET(lp->lwp_sigmask, sig); 2039 2040 crit_exit(); 2041 lp->lwp_ru.ru_nsignals++; 2042 if (lp->lwp_sig != sig) { 2043 code = 0; 2044 } else { 2045 code = lp->lwp_code; 2046 lp->lwp_code = 0; 2047 lp->lwp_sig = 0; 2048 } 2049 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2050 } 2051 done: 2052 ; 2053 } 2054 2055 /* 2056 * Kill the current process for stated reason. 2057 */ 2058 void 2059 killproc(struct proc *p, char *why) 2060 { 2061 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2062 p->p_pid, p->p_comm, 2063 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2064 ksignal(p, SIGKILL); 2065 } 2066 2067 /* 2068 * Force the current process to exit with the specified signal, dumping core 2069 * if appropriate. We bypass the normal tests for masked and caught signals, 2070 * allowing unrecoverable failures to terminate the process without changing 2071 * signal state. Mark the accounting record with the signal termination. 2072 * If dumping core, save the signal number for the debugger. Calls exit and 2073 * does not return. 2074 * 2075 * This routine does not return. 2076 */ 2077 void 2078 sigexit(struct lwp *lp, int sig) 2079 { 2080 struct proc *p = lp->lwp_proc; 2081 2082 lwkt_gettoken(&p->p_token); 2083 p->p_acflag |= AXSIG; 2084 if (sigprop(sig) & SA_CORE) { 2085 lp->lwp_sig = sig; 2086 /* 2087 * Log signals which would cause core dumps 2088 * (Log as LOG_INFO to appease those who don't want 2089 * these messages.) 2090 * XXX : Todo, as well as euid, write out ruid too 2091 */ 2092 if (coredump(lp, sig) == 0) 2093 sig |= WCOREFLAG; 2094 if (kern_logsigexit) 2095 log(LOG_INFO, 2096 "pid %d (%s), uid %d: exited on signal %d%s\n", 2097 p->p_pid, p->p_comm, 2098 p->p_ucred ? p->p_ucred->cr_uid : -1, 2099 sig &~ WCOREFLAG, 2100 sig & WCOREFLAG ? " (core dumped)" : ""); 2101 } 2102 lwkt_reltoken(&p->p_token); 2103 exit1(W_EXITCODE(0, sig)); 2104 /* NOTREACHED */ 2105 } 2106 2107 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2108 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2109 sizeof(corefilename), "process corefile name format string"); 2110 2111 /* 2112 * expand_name(name, uid, pid) 2113 * Expand the name described in corefilename, using name, uid, and pid. 2114 * corefilename is a kprintf-like string, with three format specifiers: 2115 * %N name of process ("name") 2116 * %P process id (pid) 2117 * %U user id (uid) 2118 * For example, "%N.core" is the default; they can be disabled completely 2119 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2120 * This is controlled by the sysctl variable kern.corefile (see above). 2121 */ 2122 2123 static char * 2124 expand_name(const char *name, uid_t uid, pid_t pid) 2125 { 2126 char *temp; 2127 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2128 int i, n; 2129 char *format = corefilename; 2130 size_t namelen; 2131 2132 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2133 if (temp == NULL) 2134 return NULL; 2135 namelen = strlen(name); 2136 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2137 int l; 2138 switch (format[i]) { 2139 case '%': /* Format character */ 2140 i++; 2141 switch (format[i]) { 2142 case '%': 2143 temp[n++] = '%'; 2144 break; 2145 case 'N': /* process name */ 2146 if ((n + namelen) > MAXPATHLEN) { 2147 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2148 pid, name, uid, temp, name); 2149 kfree(temp, M_TEMP); 2150 return NULL; 2151 } 2152 memcpy(temp+n, name, namelen); 2153 n += namelen; 2154 break; 2155 case 'P': /* process id */ 2156 l = ksprintf(buf, "%u", pid); 2157 if ((n + l) > MAXPATHLEN) { 2158 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2159 pid, name, uid, temp, name); 2160 kfree(temp, M_TEMP); 2161 return NULL; 2162 } 2163 memcpy(temp+n, buf, l); 2164 n += l; 2165 break; 2166 case 'U': /* user id */ 2167 l = ksprintf(buf, "%u", uid); 2168 if ((n + l) > MAXPATHLEN) { 2169 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2170 pid, name, uid, temp, name); 2171 kfree(temp, M_TEMP); 2172 return NULL; 2173 } 2174 memcpy(temp+n, buf, l); 2175 n += l; 2176 break; 2177 default: 2178 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2179 } 2180 break; 2181 default: 2182 temp[n++] = format[i]; 2183 } 2184 } 2185 temp[n] = '\0'; 2186 return temp; 2187 } 2188 2189 /* 2190 * Dump a process' core. The main routine does some 2191 * policy checking, and creates the name of the coredump; 2192 * then it passes on a vnode and a size limit to the process-specific 2193 * coredump routine if there is one; if there _is not_ one, it returns 2194 * ENOSYS; otherwise it returns the error from the process-specific routine. 2195 * 2196 * The parameter `lp' is the lwp which triggered the coredump. 2197 */ 2198 2199 static int 2200 coredump(struct lwp *lp, int sig) 2201 { 2202 struct proc *p = lp->lwp_proc; 2203 struct vnode *vp; 2204 struct ucred *cred = p->p_ucred; 2205 struct flock lf; 2206 struct nlookupdata nd; 2207 struct vattr vattr; 2208 int error, error1; 2209 char *name; /* name of corefile */ 2210 off_t limit; 2211 2212 STOPEVENT(p, S_CORE, 0); 2213 2214 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2215 return (EFAULT); 2216 2217 /* 2218 * Note that the bulk of limit checking is done after 2219 * the corefile is created. The exception is if the limit 2220 * for corefiles is 0, in which case we don't bother 2221 * creating the corefile at all. This layout means that 2222 * a corefile is truncated instead of not being created, 2223 * if it is larger than the limit. 2224 */ 2225 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2226 if (limit == 0) 2227 return EFBIG; 2228 2229 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2230 if (name == NULL) 2231 return (EINVAL); 2232 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2233 if (error == 0) 2234 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2235 kfree(name, M_TEMP); 2236 if (error) { 2237 nlookup_done(&nd); 2238 return (error); 2239 } 2240 vp = nd.nl_open_vp; 2241 nd.nl_open_vp = NULL; 2242 nlookup_done(&nd); 2243 2244 vn_unlock(vp); 2245 lf.l_whence = SEEK_SET; 2246 lf.l_start = 0; 2247 lf.l_len = 0; 2248 lf.l_type = F_WRLCK; 2249 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2250 if (error) 2251 goto out2; 2252 2253 /* Don't dump to non-regular files or files with links. */ 2254 if (vp->v_type != VREG || 2255 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2256 error = EFAULT; 2257 goto out1; 2258 } 2259 2260 /* Don't dump to files current user does not own */ 2261 if (vattr.va_uid != p->p_ucred->cr_uid) { 2262 error = EFAULT; 2263 goto out1; 2264 } 2265 2266 VATTR_NULL(&vattr); 2267 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2268 vattr.va_size = 0; 2269 VOP_SETATTR(vp, &vattr, cred); 2270 p->p_acflag |= ACORE; 2271 vn_unlock(vp); 2272 2273 error = p->p_sysent->sv_coredump ? 2274 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2275 2276 out1: 2277 lf.l_type = F_UNLCK; 2278 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2279 out2: 2280 error1 = vn_close(vp, FWRITE); 2281 if (error == 0) 2282 error = error1; 2283 return (error); 2284 } 2285 2286 /* 2287 * Nonexistent system call-- signal process (may want to handle it). 2288 * Flag error in case process won't see signal immediately (blocked or ignored). 2289 * 2290 * MPALMOSTSAFE 2291 */ 2292 /* ARGSUSED */ 2293 int 2294 sys_nosys(struct nosys_args *args) 2295 { 2296 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2297 return (EINVAL); 2298 } 2299 2300 /* 2301 * Send a SIGIO or SIGURG signal to a process or process group using 2302 * stored credentials rather than those of the current process. 2303 */ 2304 void 2305 pgsigio(struct sigio *sigio, int sig, int checkctty) 2306 { 2307 if (sigio == NULL) 2308 return; 2309 2310 if (sigio->sio_pgid > 0) { 2311 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2312 sigio->sio_proc)) 2313 ksignal(sigio->sio_proc, sig); 2314 } else if (sigio->sio_pgid < 0) { 2315 struct proc *p; 2316 struct pgrp *pg = sigio->sio_pgrp; 2317 2318 /* 2319 * Must interlock all signals against fork 2320 */ 2321 pgref(pg); 2322 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2323 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2324 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2325 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2326 ksignal(p, sig); 2327 } 2328 lockmgr(&pg->pg_lock, LK_RELEASE); 2329 pgrel(pg); 2330 } 2331 } 2332 2333 static int 2334 filt_sigattach(struct knote *kn) 2335 { 2336 struct proc *p = curproc; 2337 2338 kn->kn_ptr.p_proc = p; 2339 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2340 2341 /* XXX lock the proc here while adding to the list? */ 2342 knote_insert(&p->p_klist, kn); 2343 2344 return (0); 2345 } 2346 2347 static void 2348 filt_sigdetach(struct knote *kn) 2349 { 2350 struct proc *p = kn->kn_ptr.p_proc; 2351 2352 knote_remove(&p->p_klist, kn); 2353 } 2354 2355 /* 2356 * signal knotes are shared with proc knotes, so we apply a mask to 2357 * the hint in order to differentiate them from process hints. This 2358 * could be avoided by using a signal-specific knote list, but probably 2359 * isn't worth the trouble. 2360 */ 2361 static int 2362 filt_signal(struct knote *kn, long hint) 2363 { 2364 if (hint & NOTE_SIGNAL) { 2365 hint &= ~NOTE_SIGNAL; 2366 2367 if (kn->kn_id == hint) 2368 kn->kn_data++; 2369 } 2370 return (kn->kn_data != 0); 2371 } 2372