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 struct proc *q; 1044 sig_t action; 1045 int prop; 1046 1047 if (sig > _SIG_MAXSIG || sig <= 0) { 1048 kprintf("lwpsignal: signal %d\n", sig); 1049 panic("lwpsignal signal number"); 1050 } 1051 1052 KKASSERT(lp == NULL || lp->lwp_proc == p); 1053 1054 PHOLD(p); 1055 lwkt_gettoken(&p->p_token); 1056 1057 prop = sigprop(sig); 1058 1059 /* 1060 * If proc is traced, always give parent a chance; 1061 * if signal event is tracked by procfs, give *that* 1062 * a chance, as well. 1063 */ 1064 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 1065 action = SIG_DFL; 1066 } else { 1067 /* 1068 * Do not try to deliver signals to an exiting lwp. Note 1069 * that we must still deliver the signal if P_WEXIT is set 1070 * in the process flags. 1071 */ 1072 if (lp && (lp->lwp_flag & LWP_WEXIT)) { 1073 lwkt_reltoken(&p->p_token); 1074 PRELE(p); 1075 return; 1076 } 1077 1078 /* 1079 * If the signal is being ignored, then we forget about 1080 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1081 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1082 */ 1083 if (SIGISMEMBER(p->p_sigignore, sig)) { 1084 /* 1085 * Even if a signal is set SIG_IGN, it may still be 1086 * lurking in a kqueue. 1087 */ 1088 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1089 lwkt_reltoken(&p->p_token); 1090 PRELE(p); 1091 return; 1092 } 1093 if (SIGISMEMBER(p->p_sigcatch, sig)) 1094 action = SIG_CATCH; 1095 else 1096 action = SIG_DFL; 1097 } 1098 1099 /* 1100 * If continuing, clear any pending STOP signals. 1101 */ 1102 if (prop & SA_CONT) 1103 SIG_STOPSIGMASK(p->p_siglist); 1104 1105 if (prop & SA_STOP) { 1106 /* 1107 * If sending a tty stop signal to a member of an orphaned 1108 * process group, discard the signal here if the action 1109 * is default; don't stop the process below if sleeping, 1110 * and don't clear any pending SIGCONT. 1111 */ 1112 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 1113 action == SIG_DFL) { 1114 lwkt_reltoken(&p->p_token); 1115 PRELE(p); 1116 return; 1117 } 1118 SIG_CONTSIGMASK(p->p_siglist); 1119 p->p_flag &= ~P_CONTINUED; 1120 } 1121 1122 crit_enter(); 1123 1124 if (p->p_stat == SSTOP) { 1125 /* 1126 * Nobody can handle this signal, add it to the lwp or 1127 * process pending list 1128 */ 1129 if (lp) 1130 SIGADDSET(lp->lwp_siglist, sig); 1131 else 1132 SIGADDSET(p->p_siglist, sig); 1133 1134 /* 1135 * If the process is stopped and is being traced, then no 1136 * further action is necessary. 1137 */ 1138 if (p->p_flag & P_TRACED) 1139 goto out; 1140 1141 /* 1142 * If the process is stopped and receives a KILL signal, 1143 * make the process runnable. 1144 */ 1145 if (sig == SIGKILL) { 1146 proc_unstop(p); 1147 goto active_process; 1148 } 1149 1150 /* 1151 * If the process is stopped and receives a CONT signal, 1152 * then try to make the process runnable again. 1153 */ 1154 if (prop & SA_CONT) { 1155 /* 1156 * If SIGCONT is default (or ignored), we continue the 1157 * process but don't leave the signal in p_siglist, as 1158 * it has no further action. If SIGCONT is held, we 1159 * continue the process and leave the signal in 1160 * p_siglist. If the process catches SIGCONT, let it 1161 * handle the signal itself. 1162 * 1163 * XXX what if the signal is being held blocked? 1164 * 1165 * Token required to interlock kern_wait(). 1166 * Reparenting can also cause a race so we have to 1167 * hold (q). 1168 */ 1169 q = p->p_pptr; 1170 PHOLD(q); 1171 lwkt_gettoken(&q->p_token); 1172 p->p_flag |= P_CONTINUED; 1173 wakeup(q); 1174 if (action == SIG_DFL) 1175 SIGDELSET(p->p_siglist, sig); 1176 proc_unstop(p); 1177 lwkt_reltoken(&q->p_token); 1178 PRELE(q); 1179 if (action == SIG_CATCH) 1180 goto active_process; 1181 goto out; 1182 } 1183 1184 /* 1185 * If the process is stopped and receives another STOP 1186 * signal, we do not need to stop it again. If we did 1187 * the shell could get confused. 1188 * 1189 * However, if the current/preempted lwp is part of the 1190 * process receiving the signal, we need to keep it, 1191 * so that this lwp can stop in issignal() later, as 1192 * we don't want to wait until it reaches userret! 1193 */ 1194 if (prop & SA_STOP) { 1195 if (lwkt_preempted_proc() == NULL || 1196 lwkt_preempted_proc()->lwp_proc != p) 1197 SIGDELSET(p->p_siglist, sig); 1198 } 1199 1200 /* 1201 * Otherwise the process is stopped and it received some 1202 * signal, which does not change its stopped state. 1203 * 1204 * We have to select one thread to set LWP_BREAKTSLEEP, 1205 * so that the current signal will break the sleep 1206 * as soon as a SA_CONT signal will unstop the process. 1207 */ 1208 if (lp == NULL) 1209 lp = find_lwp_for_signal(p, sig); 1210 if (lp != NULL && 1211 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP)) 1212 lp->lwp_flag |= LWP_BREAKTSLEEP; 1213 goto out; 1214 1215 /* NOTREACHED */ 1216 } 1217 /* else not stopped */ 1218 active_process: 1219 1220 /* 1221 * Never deliver a lwp-specific signal to a random lwp. 1222 */ 1223 if (lp == NULL) { 1224 lp = find_lwp_for_signal(p, sig); 1225 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig)) 1226 lp = NULL; 1227 } 1228 1229 /* 1230 * Deliver to the process generically if (1) the signal is being 1231 * sent to any thread or (2) we could not find a thread to deliver 1232 * it to. 1233 */ 1234 if (lp == NULL) { 1235 SIGADDSET(p->p_siglist, sig); 1236 goto out; 1237 } 1238 1239 /* 1240 * Deliver to a specific LWP whether it masks it or not. It will 1241 * not be dispatched if masked but we must still deliver it. 1242 */ 1243 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1244 (p->p_flag & P_TRACED) == 0) { 1245 p->p_nice = NZERO; 1246 } 1247 1248 /* 1249 * If the process receives a STOP signal which indeed needs to 1250 * stop the process, do so. If the process chose to catch the 1251 * signal, it will be treated like any other signal. 1252 */ 1253 if ((prop & SA_STOP) && action == SIG_DFL) { 1254 /* 1255 * If a child holding parent blocked, stopping 1256 * could cause deadlock. Take no action at this 1257 * time. 1258 */ 1259 if (p->p_flag & P_PPWAIT) { 1260 SIGADDSET(p->p_siglist, sig); 1261 goto out; 1262 } 1263 1264 /* 1265 * Do not actually try to manipulate the process, but simply 1266 * stop it. Lwps will stop as soon as they safely can. 1267 */ 1268 p->p_xstat = sig; 1269 proc_stop(p); 1270 goto out; 1271 } 1272 1273 /* 1274 * If it is a CONT signal with default action, just ignore it. 1275 */ 1276 if ((prop & SA_CONT) && action == SIG_DFL) 1277 goto out; 1278 1279 /* 1280 * Mark signal pending at this specific thread. 1281 */ 1282 SIGADDSET(lp->lwp_siglist, sig); 1283 1284 lwp_signotify(lp); 1285 1286 out: 1287 lwkt_reltoken(&p->p_token); 1288 PRELE(p); 1289 crit_exit(); 1290 } 1291 1292 /* 1293 * p->p_token must be held 1294 */ 1295 static void 1296 lwp_signotify(struct lwp *lp) 1297 { 1298 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token); 1299 crit_enter(); 1300 1301 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) { 1302 /* 1303 * Thread is in tsleep. 1304 */ 1305 1306 /* 1307 * If the thread is sleeping uninterruptibly 1308 * we can't interrupt the sleep... the signal will 1309 * be noticed when the lwp returns through 1310 * trap() or syscall(). 1311 * 1312 * Otherwise the signal can interrupt the sleep. 1313 * 1314 * If the process is traced, the lwp will handle the 1315 * tracing in issignal() when it returns to userland. 1316 */ 1317 if (lp->lwp_flag & LWP_SINTR) { 1318 /* 1319 * Make runnable and break out of any tsleep as well. 1320 */ 1321 lp->lwp_flag |= LWP_BREAKTSLEEP; 1322 setrunnable(lp); 1323 } 1324 } else { 1325 /* 1326 * Otherwise the thread is running 1327 * 1328 * LSRUN does nothing with the signal, other than kicking 1329 * ourselves if we are running. 1330 * SZOMB and SIDL mean that it will either never be noticed, 1331 * or noticed very soon. 1332 * 1333 * Note that lwp_thread may be NULL or may not be completely 1334 * initialized if the process is in the SIDL or SZOMB state. 1335 * 1336 * For SMP we may have to forward the request to another cpu. 1337 * YYY the MP lock prevents the target process from moving 1338 * to another cpu, see kern/kern_switch.c 1339 * 1340 * If the target thread is waiting on its message port, 1341 * wakeup the target thread so it can check (or ignore) 1342 * the new signal. YYY needs cleanup. 1343 */ 1344 if (lp == lwkt_preempted_proc()) { 1345 signotify(); 1346 } else if (lp->lwp_stat == LSRUN) { 1347 struct thread *td = lp->lwp_thread; 1348 struct proc *p __debugvar = lp->lwp_proc; 1349 1350 KASSERT(td != NULL, 1351 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1352 p->p_pid, lp->lwp_tid, lp->lwp_stat, 1353 p->p_flag, lp->lwp_flag)); 1354 1355 /* 1356 * To prevent a MP race with TDF_SINTR we must 1357 * schedule the thread on the correct cpu. 1358 */ 1359 #ifdef SMP 1360 if (td->td_gd != mycpu) { 1361 LWPHOLD(lp); 1362 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1363 } else 1364 #endif 1365 if (td->td_flags & TDF_SINTR) 1366 lwkt_schedule(td); 1367 } 1368 } 1369 crit_exit(); 1370 } 1371 1372 #ifdef SMP 1373 1374 /* 1375 * This function is called via an IPI. We will be in a critical section but 1376 * the MP lock will NOT be held. The passed lp will be held. 1377 * 1378 * We must essentially repeat the code at the end of lwp_signotify(), 1379 * in particular rechecking all races. If we are still not on the 1380 * correct cpu we leave the lwp ref intact and continue the chase. 1381 * 1382 * XXX this may still not be entirely correct, since we are checking 1383 * lwp_stat asynchronously. 1384 */ 1385 static void 1386 signotify_remote(void *arg) 1387 { 1388 struct lwp *lp = arg; 1389 thread_t td; 1390 1391 if (lp == lwkt_preempted_proc()) { 1392 signotify(); 1393 } else if (lp->lwp_stat == LSRUN) { 1394 /* 1395 * To prevent a MP race with TDF_SINTR we must 1396 * schedule the thread on the correct cpu. 1397 */ 1398 td = lp->lwp_thread; 1399 if (td->td_gd != mycpu) { 1400 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1401 return; 1402 /* NOT REACHED */ 1403 } 1404 if (td->td_flags & TDF_SINTR) 1405 lwkt_schedule(td); 1406 } 1407 LWPRELE(lp); 1408 } 1409 1410 #endif 1411 1412 /* 1413 * Caller must hold p->p_token 1414 */ 1415 void 1416 proc_stop(struct proc *p) 1417 { 1418 struct proc *q; 1419 struct lwp *lp; 1420 1421 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1422 crit_enter(); 1423 1424 /* If somebody raced us, be happy with it */ 1425 if (p->p_stat == SSTOP || p->p_stat == SZOMB) { 1426 crit_exit(); 1427 return; 1428 } 1429 p->p_stat = SSTOP; 1430 1431 FOREACH_LWP_IN_PROC(lp, p) { 1432 switch (lp->lwp_stat) { 1433 case LSSTOP: 1434 /* 1435 * Do nothing, we are already counted in 1436 * p_nstopped. 1437 */ 1438 break; 1439 1440 case LSSLEEP: 1441 /* 1442 * We're sleeping, but we will stop before 1443 * returning to userspace, so count us 1444 * as stopped as well. We set LWP_WSTOP 1445 * to signal the lwp that it should not 1446 * increase p_nstopped when reaching tstop(). 1447 */ 1448 if ((lp->lwp_flag & LWP_WSTOP) == 0) { 1449 lp->lwp_flag |= LWP_WSTOP; 1450 ++p->p_nstopped; 1451 } 1452 break; 1453 1454 case LSRUN: 1455 /* 1456 * We might notify ourself, but that's not 1457 * a problem. 1458 */ 1459 lwp_signotify(lp); 1460 break; 1461 } 1462 } 1463 1464 if (p->p_nstopped == p->p_nthreads) { 1465 /* 1466 * Token required to interlock kern_wait(). Reparenting can 1467 * also cause a race so we have to hold (q). 1468 */ 1469 q = p->p_pptr; 1470 PHOLD(q); 1471 lwkt_gettoken(&q->p_token); 1472 p->p_flag &= ~P_WAITED; 1473 wakeup(q); 1474 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1475 ksignal(p->p_pptr, SIGCHLD); 1476 lwkt_reltoken(&q->p_token); 1477 PRELE(q); 1478 } 1479 crit_exit(); 1480 } 1481 1482 /* 1483 * Caller must hold proc_token 1484 */ 1485 void 1486 proc_unstop(struct proc *p) 1487 { 1488 struct lwp *lp; 1489 1490 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1491 crit_enter(); 1492 1493 if (p->p_stat != SSTOP) { 1494 crit_exit(); 1495 return; 1496 } 1497 1498 p->p_stat = SACTIVE; 1499 1500 FOREACH_LWP_IN_PROC(lp, p) { 1501 switch (lp->lwp_stat) { 1502 case LSRUN: 1503 /* 1504 * Uh? Not stopped? Well, I guess that's okay. 1505 */ 1506 if (bootverbose) 1507 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1508 p->p_pid, lp->lwp_tid); 1509 break; 1510 1511 case LSSLEEP: 1512 /* 1513 * Still sleeping. Don't bother waking it up. 1514 * However, if this thread was counted as 1515 * stopped, undo this. 1516 * 1517 * Nevertheless we call setrunnable() so that it 1518 * will wake up in case a signal or timeout arrived 1519 * in the meantime. 1520 */ 1521 if (lp->lwp_flag & LWP_WSTOP) { 1522 lp->lwp_flag &= ~LWP_WSTOP; 1523 --p->p_nstopped; 1524 } else { 1525 if (bootverbose) 1526 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1527 p->p_pid, lp->lwp_tid); 1528 } 1529 /* FALLTHROUGH */ 1530 1531 case LSSTOP: 1532 setrunnable(lp); 1533 break; 1534 1535 } 1536 } 1537 crit_exit(); 1538 } 1539 1540 /* 1541 * No requirements. 1542 */ 1543 static int 1544 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1545 { 1546 sigset_t savedmask, set; 1547 struct proc *p = curproc; 1548 struct lwp *lp = curthread->td_lwp; 1549 int error, sig, hz, timevalid = 0; 1550 struct timespec rts, ets, ts; 1551 struct timeval tv; 1552 1553 error = 0; 1554 sig = 0; 1555 ets.tv_sec = 0; /* silence compiler warning */ 1556 ets.tv_nsec = 0; /* silence compiler warning */ 1557 SIG_CANTMASK(waitset); 1558 savedmask = lp->lwp_sigmask; 1559 1560 if (timeout) { 1561 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1562 timeout->tv_nsec < 1000000000) { 1563 timevalid = 1; 1564 getnanouptime(&rts); 1565 ets = rts; 1566 timespecadd(&ets, timeout); 1567 } 1568 } 1569 1570 for (;;) { 1571 set = lwp_sigpend(lp); 1572 SIGSETAND(set, waitset); 1573 if ((sig = sig_ffs(&set)) != 0) { 1574 SIGFILLSET(lp->lwp_sigmask); 1575 SIGDELSET(lp->lwp_sigmask, sig); 1576 SIG_CANTMASK(lp->lwp_sigmask); 1577 sig = issignal(lp, 1); 1578 /* 1579 * It may be a STOP signal, in the case, issignal 1580 * returns 0, because we may stop there, and new 1581 * signal can come in, we should restart if we got 1582 * nothing. 1583 */ 1584 if (sig == 0) 1585 continue; 1586 else 1587 break; 1588 } 1589 1590 /* 1591 * Previous checking got nothing, and we retried but still 1592 * got nothing, we should return the error status. 1593 */ 1594 if (error) 1595 break; 1596 1597 /* 1598 * POSIX says this must be checked after looking for pending 1599 * signals. 1600 */ 1601 if (timeout) { 1602 if (timevalid == 0) { 1603 error = EINVAL; 1604 break; 1605 } 1606 getnanouptime(&rts); 1607 if (timespeccmp(&rts, &ets, >=)) { 1608 error = EAGAIN; 1609 break; 1610 } 1611 ts = ets; 1612 timespecsub(&ts, &rts); 1613 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1614 hz = tvtohz_high(&tv); 1615 } else { 1616 hz = 0; 1617 } 1618 1619 lp->lwp_sigmask = savedmask; 1620 SIGSETNAND(lp->lwp_sigmask, waitset); 1621 /* 1622 * We won't ever be woken up. Instead, our sleep will 1623 * be broken in lwpsignal(). 1624 */ 1625 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1626 if (timeout) { 1627 if (error == ERESTART) { 1628 /* can not restart a timeout wait. */ 1629 error = EINTR; 1630 } else if (error == EAGAIN) { 1631 /* will calculate timeout by ourself. */ 1632 error = 0; 1633 } 1634 } 1635 /* Retry ... */ 1636 } 1637 1638 lp->lwp_sigmask = savedmask; 1639 if (sig) { 1640 error = 0; 1641 bzero(info, sizeof(*info)); 1642 info->si_signo = sig; 1643 lwp_delsig(lp, sig); /* take the signal! */ 1644 1645 if (sig == SIGKILL) { 1646 sigexit(lp, sig); 1647 /* NOT REACHED */ 1648 } 1649 } 1650 1651 return (error); 1652 } 1653 1654 /* 1655 * MPALMOSTSAFE 1656 */ 1657 int 1658 sys_sigtimedwait(struct sigtimedwait_args *uap) 1659 { 1660 struct timespec ts; 1661 struct timespec *timeout; 1662 sigset_t set; 1663 siginfo_t info; 1664 int error; 1665 1666 if (uap->timeout) { 1667 error = copyin(uap->timeout, &ts, sizeof(ts)); 1668 if (error) 1669 return (error); 1670 timeout = &ts; 1671 } else { 1672 timeout = NULL; 1673 } 1674 error = copyin(uap->set, &set, sizeof(set)); 1675 if (error) 1676 return (error); 1677 error = kern_sigtimedwait(set, &info, timeout); 1678 if (error) 1679 return (error); 1680 if (uap->info) 1681 error = copyout(&info, uap->info, sizeof(info)); 1682 /* Repost if we got an error. */ 1683 /* 1684 * XXX lwp 1685 * 1686 * This could transform a thread-specific signal to another 1687 * thread / process pending signal. 1688 */ 1689 if (error) { 1690 ksignal(curproc, info.si_signo); 1691 } else { 1692 uap->sysmsg_result = info.si_signo; 1693 } 1694 return (error); 1695 } 1696 1697 /* 1698 * MPALMOSTSAFE 1699 */ 1700 int 1701 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1702 { 1703 siginfo_t info; 1704 sigset_t set; 1705 int error; 1706 1707 error = copyin(uap->set, &set, sizeof(set)); 1708 if (error) 1709 return (error); 1710 error = kern_sigtimedwait(set, &info, NULL); 1711 if (error) 1712 return (error); 1713 if (uap->info) 1714 error = copyout(&info, uap->info, sizeof(info)); 1715 /* Repost if we got an error. */ 1716 /* 1717 * XXX lwp 1718 * 1719 * This could transform a thread-specific signal to another 1720 * thread / process pending signal. 1721 */ 1722 if (error) { 1723 ksignal(curproc, info.si_signo); 1724 } else { 1725 uap->sysmsg_result = info.si_signo; 1726 } 1727 return (error); 1728 } 1729 1730 /* 1731 * If the current process has received a signal that would interrupt a 1732 * system call, return EINTR or ERESTART as appropriate. 1733 */ 1734 int 1735 iscaught(struct lwp *lp) 1736 { 1737 struct proc *p = lp->lwp_proc; 1738 int sig; 1739 1740 if (p) { 1741 if ((sig = CURSIG(lp)) != 0) { 1742 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1743 return (EINTR); 1744 return (ERESTART); 1745 } 1746 } 1747 return(EWOULDBLOCK); 1748 } 1749 1750 /* 1751 * If the current process has received a signal (should be caught or cause 1752 * termination, should interrupt current syscall), return the signal number. 1753 * Stop signals with default action are processed immediately, then cleared; 1754 * they aren't returned. This is checked after each entry to the system for 1755 * a syscall or trap (though this can usually be done without calling issignal 1756 * by checking the pending signal masks in the CURSIG macro). 1757 * 1758 * This routine is called via CURSIG/__cursig. We will acquire and release 1759 * p->p_token but if the caller needs to interlock the test the caller must 1760 * also hold p->p_token. 1761 * 1762 * while (sig = CURSIG(curproc)) 1763 * postsig(sig); 1764 * 1765 * MPSAFE 1766 */ 1767 int 1768 issignal(struct lwp *lp, int maytrace) 1769 { 1770 struct proc *p = lp->lwp_proc; 1771 sigset_t mask; 1772 int sig, prop; 1773 1774 lwkt_gettoken(&p->p_token); 1775 1776 for (;;) { 1777 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1778 1779 /* 1780 * If this process is supposed to stop, stop this thread. 1781 */ 1782 if (p->p_stat == SSTOP) 1783 tstop(); 1784 1785 mask = lwp_sigpend(lp); 1786 SIGSETNAND(mask, lp->lwp_sigmask); 1787 if (p->p_flag & P_PPWAIT) 1788 SIG_STOPSIGMASK(mask); 1789 if (SIGISEMPTY(mask)) { /* no signal to send */ 1790 lwkt_reltoken(&p->p_token); 1791 return (0); 1792 } 1793 sig = sig_ffs(&mask); 1794 1795 STOPEVENT(p, S_SIG, sig); 1796 1797 /* 1798 * We should see pending but ignored signals 1799 * only if P_TRACED was on when they were posted. 1800 */ 1801 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1802 lwp_delsig(lp, sig); 1803 continue; 1804 } 1805 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1806 /* 1807 * If traced, always stop, and stay stopped until 1808 * released by the parent. 1809 * 1810 * NOTE: SSTOP may get cleared during the loop, 1811 * but we do not re-notify the parent if we have 1812 * to loop several times waiting for the parent 1813 * to let us continue. 1814 * 1815 * XXX not sure if this is still true 1816 */ 1817 p->p_xstat = sig; 1818 proc_stop(p); 1819 do { 1820 tstop(); 1821 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1822 1823 /* 1824 * If parent wants us to take the signal, 1825 * then it will leave it in p->p_xstat; 1826 * otherwise we just look for signals again. 1827 */ 1828 lwp_delsig(lp, sig); /* clear old signal */ 1829 sig = p->p_xstat; 1830 if (sig == 0) 1831 continue; 1832 1833 /* 1834 * Put the new signal into p_siglist. If the 1835 * signal is being masked, look for other signals. 1836 * 1837 * XXX lwp might need a call to ksignal() 1838 */ 1839 SIGADDSET(p->p_siglist, sig); 1840 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1841 continue; 1842 1843 /* 1844 * If the traced bit got turned off, go back up 1845 * to the top to rescan signals. This ensures 1846 * that p_sig* and ps_sigact are consistent. 1847 */ 1848 if ((p->p_flag & P_TRACED) == 0) 1849 continue; 1850 } 1851 1852 prop = sigprop(sig); 1853 1854 /* 1855 * Decide whether the signal should be returned. 1856 * Return the signal's number, or fall through 1857 * to clear it from the pending mask. 1858 */ 1859 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1860 case (intptr_t)SIG_DFL: 1861 /* 1862 * Don't take default actions on system processes. 1863 */ 1864 if (p->p_pid <= 1) { 1865 #ifdef DIAGNOSTIC 1866 /* 1867 * Are you sure you want to ignore SIGSEGV 1868 * in init? XXX 1869 */ 1870 kprintf("Process (pid %lu) got signal %d\n", 1871 (u_long)p->p_pid, sig); 1872 #endif 1873 break; /* == ignore */ 1874 } 1875 1876 /* 1877 * Handle the in-kernel checkpoint action 1878 */ 1879 if (prop & SA_CKPT) { 1880 checkpoint_signal_handler(lp); 1881 break; 1882 } 1883 1884 /* 1885 * If there is a pending stop signal to process 1886 * with default action, stop here, 1887 * then clear the signal. However, 1888 * if process is member of an orphaned 1889 * process group, ignore tty stop signals. 1890 */ 1891 if (prop & SA_STOP) { 1892 if (p->p_flag & P_TRACED || 1893 (p->p_pgrp->pg_jobc == 0 && 1894 prop & SA_TTYSTOP)) 1895 break; /* == ignore */ 1896 p->p_xstat = sig; 1897 proc_stop(p); 1898 tstop(); 1899 break; 1900 } else if (prop & SA_IGNORE) { 1901 /* 1902 * Except for SIGCONT, shouldn't get here. 1903 * Default action is to ignore; drop it. 1904 */ 1905 break; /* == ignore */ 1906 } else { 1907 lwkt_reltoken(&p->p_token); 1908 return (sig); 1909 } 1910 1911 /*NOTREACHED*/ 1912 1913 case (intptr_t)SIG_IGN: 1914 /* 1915 * Masking above should prevent us ever trying 1916 * to take action on an ignored signal other 1917 * than SIGCONT, unless process is traced. 1918 */ 1919 if ((prop & SA_CONT) == 0 && 1920 (p->p_flag & P_TRACED) == 0) 1921 kprintf("issignal\n"); 1922 break; /* == ignore */ 1923 1924 default: 1925 /* 1926 * This signal has an action, let 1927 * postsig() process it. 1928 */ 1929 lwkt_reltoken(&p->p_token); 1930 return (sig); 1931 } 1932 lwp_delsig(lp, sig); /* take the signal! */ 1933 } 1934 /* NOTREACHED */ 1935 } 1936 1937 /* 1938 * Take the action for the specified signal 1939 * from the current set of pending signals. 1940 * 1941 * Caller must hold p->p_token 1942 */ 1943 void 1944 postsig(int sig) 1945 { 1946 struct lwp *lp = curthread->td_lwp; 1947 struct proc *p = lp->lwp_proc; 1948 struct sigacts *ps = p->p_sigacts; 1949 sig_t action; 1950 sigset_t returnmask; 1951 int code; 1952 1953 KASSERT(sig != 0, ("postsig")); 1954 1955 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1956 1957 /* 1958 * If we are a virtual kernel running an emulated user process 1959 * context, switch back to the virtual kernel context before 1960 * trying to post the signal. 1961 */ 1962 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1963 struct trapframe *tf = lp->lwp_md.md_regs; 1964 tf->tf_trapno = 0; 1965 vkernel_trap(lp, tf); 1966 } 1967 1968 lwp_delsig(lp, sig); 1969 action = ps->ps_sigact[_SIG_IDX(sig)]; 1970 #ifdef KTRACE 1971 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1972 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1973 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1974 #endif 1975 STOPEVENT(p, S_SIG, sig); 1976 1977 if (action == SIG_DFL) { 1978 /* 1979 * Default action, where the default is to kill 1980 * the process. (Other cases were ignored above.) 1981 */ 1982 sigexit(lp, sig); 1983 /* NOTREACHED */ 1984 } else { 1985 /* 1986 * If we get here, the signal must be caught. 1987 */ 1988 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1989 ("postsig action")); 1990 1991 crit_enter(); 1992 1993 /* 1994 * Reset the signal handler if asked to 1995 */ 1996 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1997 /* 1998 * See kern_sigaction() for origin of this code. 1999 */ 2000 SIGDELSET(p->p_sigcatch, sig); 2001 if (sig != SIGCONT && 2002 sigprop(sig) & SA_IGNORE) 2003 SIGADDSET(p->p_sigignore, sig); 2004 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2005 } 2006 2007 /* 2008 * Handle the mailbox case. Copyout to the appropriate 2009 * location but do not generate a signal frame. The system 2010 * call simply returns EINTR and the user is responsible for 2011 * polling the mailbox. 2012 */ 2013 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 2014 int sig_copy = sig; 2015 copyout(&sig_copy, (void *)action, sizeof(int)); 2016 curproc->p_flag |= P_MAILBOX; 2017 crit_exit(); 2018 goto done; 2019 } 2020 2021 /* 2022 * Set the signal mask and calculate the mask to restore 2023 * when the signal function returns. 2024 * 2025 * Special case: user has done a sigsuspend. Here the 2026 * current mask is not of interest, but rather the 2027 * mask from before the sigsuspend is what we want 2028 * restored after the signal processing is completed. 2029 */ 2030 if (lp->lwp_flag & LWP_OLDMASK) { 2031 returnmask = lp->lwp_oldsigmask; 2032 lp->lwp_flag &= ~LWP_OLDMASK; 2033 } else { 2034 returnmask = lp->lwp_sigmask; 2035 } 2036 2037 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2038 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2039 SIGADDSET(lp->lwp_sigmask, sig); 2040 2041 crit_exit(); 2042 lp->lwp_ru.ru_nsignals++; 2043 if (lp->lwp_sig != sig) { 2044 code = 0; 2045 } else { 2046 code = lp->lwp_code; 2047 lp->lwp_code = 0; 2048 lp->lwp_sig = 0; 2049 } 2050 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2051 } 2052 done: 2053 ; 2054 } 2055 2056 /* 2057 * Kill the current process for stated reason. 2058 */ 2059 void 2060 killproc(struct proc *p, char *why) 2061 { 2062 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2063 p->p_pid, p->p_comm, 2064 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2065 ksignal(p, SIGKILL); 2066 } 2067 2068 /* 2069 * Force the current process to exit with the specified signal, dumping core 2070 * if appropriate. We bypass the normal tests for masked and caught signals, 2071 * allowing unrecoverable failures to terminate the process without changing 2072 * signal state. Mark the accounting record with the signal termination. 2073 * If dumping core, save the signal number for the debugger. Calls exit and 2074 * does not return. 2075 * 2076 * This routine does not return. 2077 */ 2078 void 2079 sigexit(struct lwp *lp, int sig) 2080 { 2081 struct proc *p = lp->lwp_proc; 2082 2083 lwkt_gettoken(&p->p_token); 2084 p->p_acflag |= AXSIG; 2085 if (sigprop(sig) & SA_CORE) { 2086 lp->lwp_sig = sig; 2087 /* 2088 * Log signals which would cause core dumps 2089 * (Log as LOG_INFO to appease those who don't want 2090 * these messages.) 2091 * XXX : Todo, as well as euid, write out ruid too 2092 */ 2093 if (coredump(lp, sig) == 0) 2094 sig |= WCOREFLAG; 2095 if (kern_logsigexit) 2096 log(LOG_INFO, 2097 "pid %d (%s), uid %d: exited on signal %d%s\n", 2098 p->p_pid, p->p_comm, 2099 p->p_ucred ? p->p_ucred->cr_uid : -1, 2100 sig &~ WCOREFLAG, 2101 sig & WCOREFLAG ? " (core dumped)" : ""); 2102 } 2103 lwkt_reltoken(&p->p_token); 2104 exit1(W_EXITCODE(0, sig)); 2105 /* NOTREACHED */ 2106 } 2107 2108 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2109 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2110 sizeof(corefilename), "process corefile name format string"); 2111 2112 /* 2113 * expand_name(name, uid, pid) 2114 * Expand the name described in corefilename, using name, uid, and pid. 2115 * corefilename is a kprintf-like string, with three format specifiers: 2116 * %N name of process ("name") 2117 * %P process id (pid) 2118 * %U user id (uid) 2119 * For example, "%N.core" is the default; they can be disabled completely 2120 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2121 * This is controlled by the sysctl variable kern.corefile (see above). 2122 */ 2123 2124 static char * 2125 expand_name(const char *name, uid_t uid, pid_t pid) 2126 { 2127 char *temp; 2128 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2129 int i, n; 2130 char *format = corefilename; 2131 size_t namelen; 2132 2133 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2134 if (temp == NULL) 2135 return NULL; 2136 namelen = strlen(name); 2137 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2138 int l; 2139 switch (format[i]) { 2140 case '%': /* Format character */ 2141 i++; 2142 switch (format[i]) { 2143 case '%': 2144 temp[n++] = '%'; 2145 break; 2146 case 'N': /* process name */ 2147 if ((n + namelen) > MAXPATHLEN) { 2148 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2149 pid, name, uid, temp, name); 2150 kfree(temp, M_TEMP); 2151 return NULL; 2152 } 2153 memcpy(temp+n, name, namelen); 2154 n += namelen; 2155 break; 2156 case 'P': /* process id */ 2157 l = ksprintf(buf, "%u", pid); 2158 if ((n + l) > MAXPATHLEN) { 2159 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2160 pid, name, uid, temp, name); 2161 kfree(temp, M_TEMP); 2162 return NULL; 2163 } 2164 memcpy(temp+n, buf, l); 2165 n += l; 2166 break; 2167 case 'U': /* user id */ 2168 l = ksprintf(buf, "%u", uid); 2169 if ((n + l) > MAXPATHLEN) { 2170 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2171 pid, name, uid, temp, name); 2172 kfree(temp, M_TEMP); 2173 return NULL; 2174 } 2175 memcpy(temp+n, buf, l); 2176 n += l; 2177 break; 2178 default: 2179 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2180 } 2181 break; 2182 default: 2183 temp[n++] = format[i]; 2184 } 2185 } 2186 temp[n] = '\0'; 2187 return temp; 2188 } 2189 2190 /* 2191 * Dump a process' core. The main routine does some 2192 * policy checking, and creates the name of the coredump; 2193 * then it passes on a vnode and a size limit to the process-specific 2194 * coredump routine if there is one; if there _is not_ one, it returns 2195 * ENOSYS; otherwise it returns the error from the process-specific routine. 2196 * 2197 * The parameter `lp' is the lwp which triggered the coredump. 2198 */ 2199 2200 static int 2201 coredump(struct lwp *lp, int sig) 2202 { 2203 struct proc *p = lp->lwp_proc; 2204 struct vnode *vp; 2205 struct ucred *cred = p->p_ucred; 2206 struct flock lf; 2207 struct nlookupdata nd; 2208 struct vattr vattr; 2209 int error, error1; 2210 char *name; /* name of corefile */ 2211 off_t limit; 2212 2213 STOPEVENT(p, S_CORE, 0); 2214 2215 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 2216 return (EFAULT); 2217 2218 /* 2219 * Note that the bulk of limit checking is done after 2220 * the corefile is created. The exception is if the limit 2221 * for corefiles is 0, in which case we don't bother 2222 * creating the corefile at all. This layout means that 2223 * a corefile is truncated instead of not being created, 2224 * if it is larger than the limit. 2225 */ 2226 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2227 if (limit == 0) 2228 return EFBIG; 2229 2230 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2231 if (name == NULL) 2232 return (EINVAL); 2233 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2234 if (error == 0) 2235 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 2236 kfree(name, M_TEMP); 2237 if (error) { 2238 nlookup_done(&nd); 2239 return (error); 2240 } 2241 vp = nd.nl_open_vp; 2242 nd.nl_open_vp = NULL; 2243 nlookup_done(&nd); 2244 2245 vn_unlock(vp); 2246 lf.l_whence = SEEK_SET; 2247 lf.l_start = 0; 2248 lf.l_len = 0; 2249 lf.l_type = F_WRLCK; 2250 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2251 if (error) 2252 goto out2; 2253 2254 /* Don't dump to non-regular files or files with links. */ 2255 if (vp->v_type != VREG || 2256 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2257 error = EFAULT; 2258 goto out1; 2259 } 2260 2261 /* Don't dump to files current user does not own */ 2262 if (vattr.va_uid != p->p_ucred->cr_uid) { 2263 error = EFAULT; 2264 goto out1; 2265 } 2266 2267 VATTR_NULL(&vattr); 2268 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2269 vattr.va_size = 0; 2270 VOP_SETATTR(vp, &vattr, cred); 2271 p->p_acflag |= ACORE; 2272 vn_unlock(vp); 2273 2274 error = p->p_sysent->sv_coredump ? 2275 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2276 2277 out1: 2278 lf.l_type = F_UNLCK; 2279 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2280 out2: 2281 error1 = vn_close(vp, FWRITE); 2282 if (error == 0) 2283 error = error1; 2284 return (error); 2285 } 2286 2287 /* 2288 * Nonexistent system call-- signal process (may want to handle it). 2289 * Flag error in case process won't see signal immediately (blocked or ignored). 2290 * 2291 * MPALMOSTSAFE 2292 */ 2293 /* ARGSUSED */ 2294 int 2295 sys_nosys(struct nosys_args *args) 2296 { 2297 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2298 return (EINVAL); 2299 } 2300 2301 /* 2302 * Send a SIGIO or SIGURG signal to a process or process group using 2303 * stored credentials rather than those of the current process. 2304 */ 2305 void 2306 pgsigio(struct sigio *sigio, int sig, int checkctty) 2307 { 2308 if (sigio == NULL) 2309 return; 2310 2311 if (sigio->sio_pgid > 0) { 2312 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2313 sigio->sio_proc)) 2314 ksignal(sigio->sio_proc, sig); 2315 } else if (sigio->sio_pgid < 0) { 2316 struct proc *p; 2317 struct pgrp *pg = sigio->sio_pgrp; 2318 2319 /* 2320 * Must interlock all signals against fork 2321 */ 2322 pgref(pg); 2323 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2324 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2325 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2326 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 2327 ksignal(p, sig); 2328 } 2329 lockmgr(&pg->pg_lock, LK_RELEASE); 2330 pgrel(pg); 2331 } 2332 } 2333 2334 static int 2335 filt_sigattach(struct knote *kn) 2336 { 2337 struct proc *p = curproc; 2338 2339 kn->kn_ptr.p_proc = p; 2340 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2341 2342 /* XXX lock the proc here while adding to the list? */ 2343 knote_insert(&p->p_klist, kn); 2344 2345 return (0); 2346 } 2347 2348 static void 2349 filt_sigdetach(struct knote *kn) 2350 { 2351 struct proc *p = kn->kn_ptr.p_proc; 2352 2353 knote_remove(&p->p_klist, kn); 2354 } 2355 2356 /* 2357 * signal knotes are shared with proc knotes, so we apply a mask to 2358 * the hint in order to differentiate them from process hints. This 2359 * could be avoided by using a signal-specific knote list, but probably 2360 * isn't worth the trouble. 2361 */ 2362 static int 2363 filt_signal(struct knote *kn, long hint) 2364 { 2365 if (hint & NOTE_SIGNAL) { 2366 hint &= ~NOTE_SIGNAL; 2367 2368 if (kn->kn_id == hint) 2369 kn->kn_data++; 2370 } 2371 return (kn->kn_data != 0); 2372 } 2373