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 * $DragonFly: src/sys/kern/kern_sig.c,v 1.65 2007/02/18 16:15:23 corecode Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/sysproto.h> 49 #include <sys/signalvar.h> 50 #include <sys/resourcevar.h> 51 #include <sys/vnode.h> 52 #include <sys/event.h> 53 #include <sys/proc.h> 54 #include <sys/nlookup.h> 55 #include <sys/pioctl.h> 56 #include <sys/systm.h> 57 #include <sys/acct.h> 58 #include <sys/fcntl.h> 59 #include <sys/lock.h> 60 #include <sys/wait.h> 61 #include <sys/ktrace.h> 62 #include <sys/syslog.h> 63 #include <sys/stat.h> 64 #include <sys/sysent.h> 65 #include <sys/sysctl.h> 66 #include <sys/malloc.h> 67 #include <sys/interrupt.h> 68 #include <sys/unistd.h> 69 #include <sys/kern_syscall.h> 70 #include <sys/vkernel.h> 71 #include <sys/thread2.h> 72 73 #include <machine/cpu.h> 74 #include <machine/smp.h> 75 76 static int coredump(struct proc *); 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 #ifdef SMP 82 static void signotify_remote(void *arg); 83 #endif 84 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 85 struct timespec *timeout); 86 87 static int filt_sigattach(struct knote *kn); 88 static void filt_sigdetach(struct knote *kn); 89 static int filt_signal(struct knote *kn, long hint); 90 91 struct filterops sig_filtops = 92 { 0, filt_sigattach, filt_sigdetach, filt_signal }; 93 94 static int kern_logsigexit = 1; 95 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 96 &kern_logsigexit, 0, 97 "Log processes quitting on abnormal signals to syslog(3)"); 98 99 /* 100 * Can process p, with pcred pc, send the signal sig to process q? 101 */ 102 #define CANSIGNAL(q, sig) \ 103 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ 104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 105 106 /* 107 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 108 */ 109 #define CANSIGIO(ruid, uc, q) \ 110 ((uc)->cr_uid == 0 || \ 111 (ruid) == (q)->p_ucred->cr_ruid || \ 112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 113 (ruid) == (q)->p_ucred->cr_uid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_uid) 115 116 int sugid_coredump; 117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 119 120 static int do_coredump = 1; 121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 122 &do_coredump, 0, "Enable/Disable coredumps"); 123 124 /* 125 * Signal properties and actions. 126 * The array below categorizes the signals and their default actions 127 * according to the following properties: 128 */ 129 #define SA_KILL 0x01 /* terminates process by default */ 130 #define SA_CORE 0x02 /* ditto and coredumps */ 131 #define SA_STOP 0x04 /* suspend process */ 132 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 133 #define SA_IGNORE 0x10 /* ignore by default */ 134 #define SA_CONT 0x20 /* continue if suspended */ 135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 136 #define SA_CKPT 0x80 /* checkpoint process */ 137 138 139 static int sigproptbl[NSIG] = { 140 SA_KILL, /* SIGHUP */ 141 SA_KILL, /* SIGINT */ 142 SA_KILL|SA_CORE, /* SIGQUIT */ 143 SA_KILL|SA_CORE, /* SIGILL */ 144 SA_KILL|SA_CORE, /* SIGTRAP */ 145 SA_KILL|SA_CORE, /* SIGABRT */ 146 SA_KILL|SA_CORE, /* SIGEMT */ 147 SA_KILL|SA_CORE, /* SIGFPE */ 148 SA_KILL, /* SIGKILL */ 149 SA_KILL|SA_CORE, /* SIGBUS */ 150 SA_KILL|SA_CORE, /* SIGSEGV */ 151 SA_KILL|SA_CORE, /* SIGSYS */ 152 SA_KILL, /* SIGPIPE */ 153 SA_KILL, /* SIGALRM */ 154 SA_KILL, /* SIGTERM */ 155 SA_IGNORE, /* SIGURG */ 156 SA_STOP, /* SIGSTOP */ 157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 158 SA_IGNORE|SA_CONT, /* SIGCONT */ 159 SA_IGNORE, /* SIGCHLD */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 162 SA_IGNORE, /* SIGIO */ 163 SA_KILL, /* SIGXCPU */ 164 SA_KILL, /* SIGXFSZ */ 165 SA_KILL, /* SIGVTALRM */ 166 SA_KILL, /* SIGPROF */ 167 SA_IGNORE, /* SIGWINCH */ 168 SA_IGNORE, /* SIGINFO */ 169 SA_KILL, /* SIGUSR1 */ 170 SA_KILL, /* SIGUSR2 */ 171 SA_IGNORE, /* SIGTHR */ 172 SA_CKPT, /* SIGCKPT */ 173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 205 }; 206 207 static __inline int 208 sigprop(int sig) 209 { 210 211 if (sig > 0 && sig < NSIG) 212 return (sigproptbl[_SIG_IDX(sig)]); 213 return (0); 214 } 215 216 static __inline int 217 sig_ffs(sigset_t *set) 218 { 219 int i; 220 221 for (i = 0; i < _SIG_WORDS; i++) 222 if (set->__bits[i]) 223 return (ffs(set->__bits[i]) + (i * 32)); 224 return (0); 225 } 226 227 int 228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 229 { 230 struct thread *td = curthread; 231 struct proc *p = td->td_proc; 232 struct sigacts *ps = p->p_sigacts; 233 234 if (sig <= 0 || sig > _SIG_MAXSIG) 235 return (EINVAL); 236 237 if (oact) { 238 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 239 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 240 oact->sa_flags = 0; 241 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 242 oact->sa_flags |= SA_ONSTACK; 243 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 244 oact->sa_flags |= SA_RESTART; 245 if (SIGISMEMBER(ps->ps_sigreset, sig)) 246 oact->sa_flags |= SA_RESETHAND; 247 if (SIGISMEMBER(ps->ps_signodefer, sig)) 248 oact->sa_flags |= SA_NODEFER; 249 if (SIGISMEMBER(ps->ps_siginfo, sig)) 250 oact->sa_flags |= SA_SIGINFO; 251 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) 252 oact->sa_flags |= SA_MAILBOX; 253 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) 254 oact->sa_flags |= SA_NOCLDSTOP; 255 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) 256 oact->sa_flags |= SA_NOCLDWAIT; 257 } 258 if (act) { 259 /* 260 * Check for invalid requests. KILL and STOP cannot be 261 * caught. 262 */ 263 if (sig == SIGKILL || sig == SIGSTOP) { 264 if (act->sa_handler != SIG_DFL) 265 return (EINVAL); 266 #if 0 267 /* (not needed, SIG_DFL forces action to occur) */ 268 if (act->sa_flags & SA_MAILBOX) 269 return (EINVAL); 270 #endif 271 } 272 273 /* 274 * Change setting atomically. 275 */ 276 crit_enter(); 277 278 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 279 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 280 if (act->sa_flags & SA_SIGINFO) { 281 ps->ps_sigact[_SIG_IDX(sig)] = 282 (__sighandler_t *)act->sa_sigaction; 283 SIGADDSET(ps->ps_siginfo, sig); 284 } else { 285 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 286 SIGDELSET(ps->ps_siginfo, sig); 287 } 288 if (!(act->sa_flags & SA_RESTART)) 289 SIGADDSET(ps->ps_sigintr, sig); 290 else 291 SIGDELSET(ps->ps_sigintr, sig); 292 if (act->sa_flags & SA_ONSTACK) 293 SIGADDSET(ps->ps_sigonstack, sig); 294 else 295 SIGDELSET(ps->ps_sigonstack, sig); 296 if (act->sa_flags & SA_RESETHAND) 297 SIGADDSET(ps->ps_sigreset, sig); 298 else 299 SIGDELSET(ps->ps_sigreset, sig); 300 if (act->sa_flags & SA_NODEFER) 301 SIGADDSET(ps->ps_signodefer, sig); 302 else 303 SIGDELSET(ps->ps_signodefer, sig); 304 if (act->sa_flags & SA_MAILBOX) 305 SIGADDSET(ps->ps_sigmailbox, sig); 306 else 307 SIGDELSET(ps->ps_sigmailbox, sig); 308 if (sig == SIGCHLD) { 309 if (act->sa_flags & SA_NOCLDSTOP) 310 p->p_procsig->ps_flag |= PS_NOCLDSTOP; 311 else 312 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; 313 if (act->sa_flags & SA_NOCLDWAIT) { 314 /* 315 * Paranoia: since SA_NOCLDWAIT is implemented 316 * by reparenting the dying child to PID 1 (and 317 * trust it to reap the zombie), PID 1 itself 318 * is forbidden to set SA_NOCLDWAIT. 319 */ 320 if (p->p_pid == 1) 321 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 322 else 323 p->p_procsig->ps_flag |= PS_NOCLDWAIT; 324 } else { 325 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 326 } 327 } 328 /* 329 * Set bit in p_sigignore for signals that are set to SIG_IGN, 330 * and for signals set to SIG_DFL where the default is to 331 * ignore. However, don't put SIGCONT in p_sigignore, as we 332 * have to restart the process. 333 */ 334 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 335 (sigprop(sig) & SA_IGNORE && 336 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 337 /* never to be seen again */ 338 SIGDELSET(p->p_siglist, sig); 339 if (sig != SIGCONT) 340 /* easier in ksignal */ 341 SIGADDSET(p->p_sigignore, sig); 342 SIGDELSET(p->p_sigcatch, sig); 343 } else { 344 SIGDELSET(p->p_sigignore, sig); 345 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 346 SIGDELSET(p->p_sigcatch, sig); 347 else 348 SIGADDSET(p->p_sigcatch, sig); 349 } 350 351 crit_exit(); 352 } 353 return (0); 354 } 355 356 int 357 sys_sigaction(struct sigaction_args *uap) 358 { 359 struct sigaction act, oact; 360 struct sigaction *actp, *oactp; 361 int error; 362 363 actp = (uap->act != NULL) ? &act : NULL; 364 oactp = (uap->oact != NULL) ? &oact : NULL; 365 if (actp) { 366 error = copyin(uap->act, actp, sizeof(act)); 367 if (error) 368 return (error); 369 } 370 error = kern_sigaction(uap->sig, actp, oactp); 371 if (oactp && !error) { 372 error = copyout(oactp, uap->oact, sizeof(oact)); 373 } 374 return (error); 375 } 376 377 /* 378 * Initialize signal state for process 0; 379 * set to ignore signals that are ignored by default. 380 */ 381 void 382 siginit(struct proc *p) 383 { 384 int i; 385 386 for (i = 1; i <= NSIG; i++) 387 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 388 SIGADDSET(p->p_sigignore, i); 389 } 390 391 /* 392 * Reset signals for an exec of the specified process. 393 */ 394 void 395 execsigs(struct proc *p) 396 { 397 struct sigacts *ps = p->p_sigacts; 398 struct lwp *lp; 399 int sig; 400 401 /* 402 * Reset caught signals. Held signals remain held 403 * through p_sigmask (unless they were caught, 404 * and are now ignored by default). 405 */ 406 while (SIGNOTEMPTY(p->p_sigcatch)) { 407 sig = sig_ffs(&p->p_sigcatch); 408 SIGDELSET(p->p_sigcatch, sig); 409 if (sigprop(sig) & SA_IGNORE) { 410 if (sig != SIGCONT) 411 SIGADDSET(p->p_sigignore, sig); 412 SIGDELSET(p->p_siglist, sig); 413 } 414 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 415 } 416 /* 417 * Reset stack state to the user stack. 418 * Clear set of signals caught on the signal stack. 419 */ 420 lp = ONLY_LWP_IN_PROC(p); 421 lp->lwp_sigstk.ss_flags = SS_DISABLE; 422 lp->lwp_sigstk.ss_size = 0; 423 lp->lwp_sigstk.ss_sp = 0; 424 lp->lwp_flag &= ~LWP_ALTSTACK; 425 /* 426 * Reset no zombies if child dies flag as Solaris does. 427 */ 428 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; 429 } 430 431 /* 432 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 433 * 434 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 435 * p == curproc. 436 */ 437 int 438 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 439 { 440 struct thread *td = curthread; 441 struct lwp *lp = td->td_lwp; 442 int error; 443 444 if (oset != NULL) 445 *oset = lp->lwp_sigmask; 446 447 error = 0; 448 if (set != NULL) { 449 switch (how) { 450 case SIG_BLOCK: 451 SIG_CANTMASK(*set); 452 SIGSETOR(lp->lwp_sigmask, *set); 453 break; 454 case SIG_UNBLOCK: 455 SIGSETNAND(lp->lwp_sigmask, *set); 456 break; 457 case SIG_SETMASK: 458 SIG_CANTMASK(*set); 459 lp->lwp_sigmask = *set; 460 break; 461 default: 462 error = EINVAL; 463 break; 464 } 465 } 466 return (error); 467 } 468 469 /* 470 * sigprocmask() - MP SAFE 471 */ 472 int 473 sys_sigprocmask(struct sigprocmask_args *uap) 474 { 475 sigset_t set, oset; 476 sigset_t *setp, *osetp; 477 int error; 478 479 setp = (uap->set != NULL) ? &set : NULL; 480 osetp = (uap->oset != NULL) ? &oset : NULL; 481 if (setp) { 482 error = copyin(uap->set, setp, sizeof(set)); 483 if (error) 484 return (error); 485 } 486 error = kern_sigprocmask(uap->how, setp, osetp); 487 if (osetp && !error) { 488 error = copyout(osetp, uap->oset, sizeof(oset)); 489 } 490 return (error); 491 } 492 493 int 494 kern_sigpending(struct __sigset *set) 495 { 496 struct thread *td = curthread; 497 struct proc *p = td->td_proc; 498 499 *set = p->p_siglist; 500 501 return (0); 502 } 503 504 int 505 sys_sigpending(struct sigpending_args *uap) 506 { 507 sigset_t set; 508 int error; 509 510 error = kern_sigpending(&set); 511 512 if (error == 0) 513 error = copyout(&set, uap->set, sizeof(set)); 514 return (error); 515 } 516 517 /* 518 * Suspend process until signal, providing mask to be set 519 * in the meantime. 520 */ 521 int 522 kern_sigsuspend(struct __sigset *set) 523 { 524 struct thread *td = curthread; 525 struct lwp *lp = td->td_lwp; 526 struct proc *p = td->td_proc; 527 struct sigacts *ps = p->p_sigacts; 528 529 /* 530 * When returning from sigsuspend, we want 531 * the old mask to be restored after the 532 * signal handler has finished. Thus, we 533 * save it here and mark the sigacts structure 534 * to indicate this. 535 */ 536 lp->lwp_oldsigmask = lp->lwp_sigmask; 537 lp->lwp_flag |= LWP_OLDMASK; 538 539 SIG_CANTMASK(*set); 540 lp->lwp_sigmask = *set; 541 while (tsleep(ps, PCATCH, "pause", 0) == 0) 542 /* void */; 543 /* always return EINTR rather than ERESTART... */ 544 return (EINTR); 545 } 546 547 /* 548 * Note nonstandard calling convention: libc stub passes mask, not 549 * pointer, to save a copyin. 550 */ 551 int 552 sys_sigsuspend(struct sigsuspend_args *uap) 553 { 554 sigset_t mask; 555 int error; 556 557 error = copyin(uap->sigmask, &mask, sizeof(mask)); 558 if (error) 559 return (error); 560 561 error = kern_sigsuspend(&mask); 562 563 return (error); 564 } 565 566 int 567 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) 568 { 569 struct thread *td = curthread; 570 struct lwp *lp = td->td_lwp; 571 struct proc *p = td->td_proc; 572 573 if ((lp->lwp_flag & LWP_ALTSTACK) == 0) 574 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 575 576 if (oss) 577 *oss = lp->lwp_sigstk; 578 579 if (ss) { 580 if (ss->ss_flags & SS_DISABLE) { 581 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 582 return (EINVAL); 583 lp->lwp_flag &= ~LWP_ALTSTACK; 584 lp->lwp_sigstk.ss_flags = ss->ss_flags; 585 } else { 586 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 587 return (ENOMEM); 588 lp->lwp_flag |= LWP_ALTSTACK; 589 lp->lwp_sigstk = *ss; 590 } 591 } 592 593 return (0); 594 } 595 596 int 597 sys_sigaltstack(struct sigaltstack_args *uap) 598 { 599 stack_t ss, oss; 600 int error; 601 602 if (uap->ss) { 603 error = copyin(uap->ss, &ss, sizeof(ss)); 604 if (error) 605 return (error); 606 } 607 608 error = kern_sigaltstack(uap->ss ? &ss : NULL, 609 uap->oss ? &oss : NULL); 610 611 if (error == 0 && uap->oss) 612 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 613 return (error); 614 } 615 616 /* 617 * Common code for kill process group/broadcast kill. 618 * cp is calling process. 619 */ 620 struct killpg_info { 621 int nfound; 622 int sig; 623 }; 624 625 static int killpg_all_callback(struct proc *p, void *data); 626 627 static int 628 dokillpg(int sig, int pgid, int all) 629 { 630 struct killpg_info info; 631 struct proc *cp = curproc; 632 struct proc *p; 633 struct pgrp *pgrp; 634 635 info.nfound = 0; 636 info.sig = sig; 637 638 if (all) { 639 /* 640 * broadcast 641 */ 642 allproc_scan(killpg_all_callback, &info); 643 } else { 644 if (pgid == 0) { 645 /* 646 * zero pgid means send to my process group. 647 */ 648 pgrp = cp->p_pgrp; 649 } else { 650 pgrp = pgfind(pgid); 651 if (pgrp == NULL) 652 return (ESRCH); 653 } 654 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 655 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 656 if (p->p_pid <= 1 || 657 p->p_stat == SZOMB || 658 (p->p_flag & P_SYSTEM) || 659 !CANSIGNAL(p, sig)) { 660 continue; 661 } 662 ++info.nfound; 663 if (sig) 664 ksignal(p, sig); 665 } 666 lockmgr(&pgrp->pg_lock, LK_RELEASE); 667 } 668 return (info.nfound ? 0 : ESRCH); 669 } 670 671 static int 672 killpg_all_callback(struct proc *p, void *data) 673 { 674 struct killpg_info *info = data; 675 676 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) || 677 p == curproc || !CANSIGNAL(p, info->sig)) { 678 return (0); 679 } 680 ++info->nfound; 681 if (info->sig) 682 ksignal(p, info->sig); 683 return(0); 684 } 685 686 int 687 kern_kill(int sig, int pid) 688 { 689 struct thread *td = curthread; 690 struct proc *p = td->td_proc; 691 692 if ((u_int)sig > _SIG_MAXSIG) 693 return (EINVAL); 694 if (pid > 0) { 695 /* kill single process */ 696 if ((p = pfind(pid)) == NULL) 697 return (ESRCH); 698 if (!CANSIGNAL(p, sig)) 699 return (EPERM); 700 if (sig) 701 ksignal(p, sig); 702 return (0); 703 } 704 switch (pid) { 705 case -1: /* broadcast signal */ 706 return (dokillpg(sig, 0, 1)); 707 case 0: /* signal own process group */ 708 return (dokillpg(sig, 0, 0)); 709 default: /* negative explicit process group */ 710 return (dokillpg(sig, -pid, 0)); 711 } 712 /* NOTREACHED */ 713 } 714 715 int 716 sys_kill(struct kill_args *uap) 717 { 718 int error; 719 720 error = kern_kill(uap->signum, uap->pid); 721 722 return (error); 723 } 724 725 /* 726 * Send a signal to a process group. 727 */ 728 void 729 gsignal(int pgid, int sig) 730 { 731 struct pgrp *pgrp; 732 733 if (pgid && (pgrp = pgfind(pgid))) 734 pgsignal(pgrp, sig, 0); 735 } 736 737 /* 738 * Send a signal to a process group. If checktty is 1, 739 * limit to members which have a controlling terminal. 740 * 741 * pg_lock interlocks against a fork that might be in progress, to 742 * ensure that the new child process picks up the signal. 743 */ 744 void 745 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 746 { 747 struct proc *p; 748 749 if (pgrp) { 750 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 751 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 752 if (checkctty == 0 || p->p_flag & P_CONTROLT) 753 ksignal(p, sig); 754 } 755 lockmgr(&pgrp->pg_lock, LK_RELEASE); 756 } 757 } 758 759 /* 760 * Send a signal caused by a trap to the current process. 761 * If it will be caught immediately, deliver it with correct code. 762 * Otherwise, post it normally. 763 */ 764 void 765 trapsignal(struct lwp *lp, int sig, u_long code) 766 { 767 struct proc *p = lp->lwp_proc; 768 struct sigacts *ps = p->p_sigacts; 769 770 /* 771 * If we are a virtual kernel running an emulated user process 772 * context, switch back to the virtual kernel context before 773 * trying to post the signal. 774 */ 775 if (p->p_vkernel && p->p_vkernel->vk_current) { 776 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs; 777 tf->tf_trapno = 0; 778 vkernel_trap(p, tf); 779 } 780 781 782 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 783 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 784 lp->lwp_ru.ru_nsignals++; 785 #ifdef KTRACE 786 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 787 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)], 788 &lp->lwp_sigmask, code); 789 #endif 790 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 791 &lp->lwp_sigmask, code); 792 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 793 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 794 SIGADDSET(lp->lwp_sigmask, sig); 795 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 796 /* 797 * See kern_sigaction() for origin of this code. 798 */ 799 SIGDELSET(p->p_sigcatch, sig); 800 if (sig != SIGCONT && 801 sigprop(sig) & SA_IGNORE) 802 SIGADDSET(p->p_sigignore, sig); 803 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 804 } 805 } else { 806 p->p_code = code; /* XXX for core dump/debugger */ 807 p->p_sig = sig; /* XXX to verify code */ 808 ksignal(p, sig); 809 } 810 } 811 812 /* 813 * Send the signal to the process. If the signal has an action, the action 814 * is usually performed by the target process rather than the caller; we add 815 * the signal to the set of pending signals for the process. 816 * 817 * Exceptions: 818 * o When a stop signal is sent to a sleeping process that takes the 819 * default action, the process is stopped without awakening it. 820 * o SIGCONT restarts stopped processes (or puts them back to sleep) 821 * regardless of the signal action (eg, blocked or ignored). 822 * 823 * Other ignored signals are discarded immediately. 824 */ 825 void 826 ksignal(struct proc *p, int sig) 827 { 828 /* XXX lwp more intelligent lwp choice needed */ 829 struct lwp *lp = FIRST_LWP_IN_PROC(p); 830 int prop; 831 sig_t action; 832 833 if (sig > _SIG_MAXSIG || sig <= 0) { 834 kprintf("ksignal: signal %d\n", sig); 835 panic("ksignal signal number"); 836 } 837 838 crit_enter(); 839 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 840 crit_exit(); 841 842 prop = sigprop(sig); 843 844 /* 845 * If proc is traced, always give parent a chance; 846 * if signal event is tracked by procfs, give *that* 847 * a chance, as well. 848 */ 849 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) { 850 action = SIG_DFL; 851 } else { 852 /* 853 * If the signal is being ignored, 854 * then we forget about it immediately. 855 * (Note: we don't set SIGCONT in p_sigignore, 856 * and if it is set to SIG_IGN, 857 * action will be SIG_DFL here.) 858 */ 859 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) 860 return; 861 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 862 action = SIG_HOLD; 863 else if (SIGISMEMBER(p->p_sigcatch, sig)) 864 action = SIG_CATCH; 865 else 866 action = SIG_DFL; 867 } 868 869 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 870 (p->p_flag & P_TRACED) == 0) { 871 p->p_nice = NZERO; 872 } 873 874 /* 875 * If continuing, clear any pending STOP signals. 876 */ 877 if (prop & SA_CONT) 878 SIG_STOPSIGMASK(p->p_siglist); 879 880 if (prop & SA_STOP) { 881 /* 882 * If sending a tty stop signal to a member of an orphaned 883 * process group, discard the signal here if the action 884 * is default; don't stop the process below if sleeping, 885 * and don't clear any pending SIGCONT. 886 */ 887 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && 888 action == SIG_DFL) { 889 return; 890 } 891 SIG_CONTSIGMASK(p->p_siglist); 892 } 893 SIGADDSET(p->p_siglist, sig); 894 895 /* 896 * Defer further processing for signals which are held, 897 * except that stopped processes must be continued by SIGCONT. 898 */ 899 if (action == SIG_HOLD) { 900 if ((prop & SA_CONT) == 0 || p->p_stat != SSTOP) 901 return; 902 } 903 904 crit_enter(); 905 906 907 /* XXX lwp handle stop/continue */ 908 909 /* 910 * LWP is in tsleep and not stopped 911 */ 912 if (lp->lwp_stat == LSSLEEP && p->p_stat != SSTOP) { 913 /* 914 * If the process is sleeping uninterruptibly 915 * we can't interrupt the sleep... the signal will 916 * be noticed when the process returns through 917 * trap() or syscall(). 918 */ 919 if ((lp->lwp_flag & LWP_SINTR) == 0) 920 goto out; 921 922 /* 923 * If the process is sleeping and traced, make it runnable 924 * so it can discover the signal in issignal() and stop 925 * for the parent. 926 * 927 * If the process is stopped and traced, no further action 928 * is necessary. 929 */ 930 if (p->p_flag & P_TRACED) 931 goto run; 932 933 /* 934 * If the process is sleeping and SA_CONT, and the signal 935 * mode is SIG_DFL, then make the process runnable. 936 * 937 * However, do *NOT* set LWP_BREAKTSLEEP. We do not want 938 * a SIGCONT to terminate an interruptable tsleep early 939 * and generate a spurious EINTR. 940 */ 941 if ((prop & SA_CONT) && action == SIG_DFL) { 942 SIGDELSET(p->p_siglist, sig); 943 goto run_no_break; 944 } 945 946 /* 947 * If the process is sleeping and receives a STOP signal, 948 * process immediately if possible. All other (caught or 949 * default) signals cause the process to run. 950 */ 951 if (prop & SA_STOP) { 952 if (action != SIG_DFL) 953 goto run; 954 955 /* 956 * If a child holding parent blocked, stopping 957 * could cause deadlock. Take no action at this 958 * time. 959 */ 960 if (p->p_flag & P_PPWAIT) 961 goto out; 962 963 /* 964 * Do not actually try to manipulate the process while 965 * it is sleeping, simply set SSTOP to indicate that 966 * lwps should stop as soon as they safely can. 967 */ 968 SIGDELSET(p->p_siglist, sig); 969 p->p_xstat = sig; 970 proc_stop(p, 1); 971 goto out; 972 } 973 974 /* 975 * Otherwise the signal can interrupt the sleep. 976 */ 977 goto run; 978 } 979 980 /* 981 * Process is in tsleep and is stopped 982 */ 983 if (lp->lwp_stat == LSSLEEP && p->p_stat == SSTOP) { 984 /* 985 * If the process is stopped and is being traced, then no 986 * further action is necessary. 987 */ 988 if (p->p_flag & P_TRACED) 989 goto out; 990 991 /* 992 * If the process is stopped and receives a KILL signal, 993 * make the process runnable. 994 */ 995 if (sig == SIGKILL) { 996 proc_unstop(p); 997 goto out; 998 } 999 1000 /* 1001 * If the process is stopped and receives a CONT signal, 1002 * then try to make the process runnable again. 1003 */ 1004 if (prop & SA_CONT) { 1005 /* 1006 * If SIGCONT is default (or ignored), we continue the 1007 * process but don't leave the signal in p_siglist, as 1008 * it has no further action. If SIGCONT is held, we 1009 * continue the process and leave the signal in 1010 * p_siglist. If the process catches SIGCONT, let it 1011 * handle the signal itself. 1012 */ 1013 if (action == SIG_DFL) 1014 SIGDELSET(p->p_siglist, sig); 1015 proc_unstop(p); 1016 if (action == SIG_CATCH) 1017 goto run; 1018 goto out; 1019 } 1020 1021 /* 1022 * If the process is stopped and receives another STOP 1023 * signal, we do not need to stop it again. If we did 1024 * the shell could get confused. 1025 */ 1026 if (prop & SA_STOP) { 1027 SIGDELSET(p->p_siglist, sig); 1028 goto out; 1029 } 1030 1031 /* 1032 * Otherwise the process is sleeping interruptably but 1033 * is stopped, just set the LWP_BREAKTSLEEP flag and take 1034 * no further action. The next runnable action will wake 1035 * the process up. 1036 */ 1037 lp->lwp_flag |= LWP_BREAKTSLEEP; 1038 goto out; 1039 } 1040 1041 /* 1042 * Otherwise the process is running 1043 * 1044 * SRUN, SIDL, SZOMB do nothing with the signal, 1045 * other than kicking ourselves if we are running. 1046 * It will either never be noticed, or noticed very soon. 1047 * 1048 * Note that p_thread may be NULL or may not be completely 1049 * initialized if the process is in the SIDL or SZOMB state. 1050 * 1051 * For SMP we may have to forward the request to another cpu. 1052 * YYY the MP lock prevents the target process from moving 1053 * to another cpu, see kern/kern_switch.c 1054 * 1055 * If the target thread is waiting on its message port, 1056 * wakeup the target thread so it can check (or ignore) 1057 * the new signal. YYY needs cleanup. 1058 */ 1059 if (lp == lwkt_preempted_proc()) { 1060 signotify(); 1061 } else if (lp->lwp_stat == LSRUN) { 1062 struct thread *td = lp->lwp_thread; 1063 1064 KASSERT(td != NULL, 1065 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x", 1066 p->p_pid, lp->lwp_tid, lp->lwp_stat, p->p_flag, lp->lwp_flag)); 1067 1068 #ifdef SMP 1069 if (td->td_gd != mycpu) 1070 lwkt_send_ipiq(td->td_gd, signotify_remote, lp); 1071 else 1072 #endif 1073 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1074 lwkt_schedule(td); 1075 } 1076 goto out; 1077 /*NOTREACHED*/ 1078 run: 1079 /* 1080 * Make runnable and break out of any tsleep as well. 1081 */ 1082 lp->lwp_flag |= LWP_BREAKTSLEEP; 1083 run_no_break: 1084 setrunnable(lp); 1085 out: 1086 crit_exit(); 1087 } 1088 1089 #ifdef SMP 1090 1091 /* 1092 * This function is called via an IPI. We will be in a critical section but 1093 * the MP lock will NOT be held. Also note that by the time the ipi message 1094 * gets to us the process 'p' (arg) may no longer be scheduled or even valid. 1095 */ 1096 static void 1097 signotify_remote(void *arg) 1098 { 1099 struct lwp *lp = arg; 1100 1101 if (lp == lwkt_preempted_proc()) { 1102 signotify(); 1103 } else { 1104 struct thread *td = lp->lwp_thread; 1105 if (td->td_msgport.mp_flags & MSGPORTF_WAITING) 1106 lwkt_schedule(td); 1107 } 1108 } 1109 1110 #endif 1111 1112 void 1113 proc_stop(struct proc *p, int notify) 1114 { 1115 /* XXX lwp */ 1116 p->p_stat = SSTOP; 1117 p->p_flag &= ~P_WAITED; 1118 wakeup(p->p_pptr); 1119 if (notify > 1 || 1120 notify && (p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) 1121 ksignal(p->p_pptr, SIGCHLD); 1122 } 1123 1124 void 1125 proc_unstop(struct proc *p) 1126 { 1127 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */ 1128 1129 p->p_stat = SACTIVE; 1130 setrunnable(lp); 1131 } 1132 1133 static int 1134 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1135 { 1136 sigset_t savedmask, set; 1137 struct proc *p = curproc; 1138 struct lwp *lp = curthread->td_lwp; 1139 int error, sig, hz, timevalid = 0; 1140 struct timespec rts, ets, ts; 1141 struct timeval tv; 1142 1143 error = 0; 1144 sig = 0; 1145 SIG_CANTMASK(waitset); 1146 savedmask = lp->lwp_sigmask; 1147 1148 if (timeout) { 1149 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1150 timeout->tv_nsec < 1000000000) { 1151 timevalid = 1; 1152 getnanouptime(&rts); 1153 ets = rts; 1154 timespecadd(&ets, timeout); 1155 } 1156 } 1157 1158 for (;;) { 1159 set = p->p_siglist; 1160 SIGSETAND(set, waitset); 1161 if ((sig = sig_ffs(&set)) != 0) { 1162 SIGFILLSET(lp->lwp_sigmask); 1163 SIGDELSET(lp->lwp_sigmask, sig); 1164 SIG_CANTMASK(lp->lwp_sigmask); 1165 sig = issignal(lp); 1166 /* 1167 * It may be a STOP signal, in the case, issignal 1168 * returns 0, because we may stop there, and new 1169 * signal can come in, we should restart if we got 1170 * nothing. 1171 */ 1172 if (sig == 0) 1173 continue; 1174 else 1175 break; 1176 } 1177 1178 /* 1179 * Previous checking got nothing, and we retried but still 1180 * got nothing, we should return the error status. 1181 */ 1182 if (error) 1183 break; 1184 1185 /* 1186 * POSIX says this must be checked after looking for pending 1187 * signals. 1188 */ 1189 if (timeout) { 1190 if (!timevalid) { 1191 error = EINVAL; 1192 break; 1193 } 1194 getnanouptime(&rts); 1195 if (timespeccmp(&rts, &ets, >=)) { 1196 error = EAGAIN; 1197 break; 1198 } 1199 ts = ets; 1200 timespecsub(&ts, &rts); 1201 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1202 hz = tvtohz_high(&tv); 1203 } else 1204 hz = 0; 1205 1206 lp->lwp_sigmask = savedmask; 1207 SIGSETNAND(lp->lwp_sigmask, waitset); 1208 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1209 if (timeout) { 1210 if (error == ERESTART) { 1211 /* can not restart a timeout wait. */ 1212 error = EINTR; 1213 } else if (error == EAGAIN) { 1214 /* will calculate timeout by ourself. */ 1215 error = 0; 1216 } 1217 } 1218 /* Retry ... */ 1219 } 1220 1221 lp->lwp_sigmask = savedmask; 1222 if (sig) { 1223 error = 0; 1224 bzero(info, sizeof(*info)); 1225 info->si_signo = sig; 1226 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1227 1228 if (sig == SIGKILL) 1229 sigexit(p, sig); 1230 } 1231 return (error); 1232 } 1233 1234 int 1235 sys_sigtimedwait(struct sigtimedwait_args *uap) 1236 { 1237 struct timespec ts; 1238 struct timespec *timeout; 1239 sigset_t set; 1240 siginfo_t info; 1241 int error; 1242 1243 if (uap->timeout) { 1244 error = copyin(uap->timeout, &ts, sizeof(ts)); 1245 if (error) 1246 return (error); 1247 timeout = &ts; 1248 } else { 1249 timeout = NULL; 1250 } 1251 error = copyin(uap->set, &set, sizeof(set)); 1252 if (error) 1253 return (error); 1254 error = kern_sigtimedwait(set, &info, timeout); 1255 if (error) 1256 return (error); 1257 if (uap->info) 1258 error = copyout(&info, uap->info, sizeof(info)); 1259 /* Repost if we got an error. */ 1260 if (error) 1261 ksignal(curproc, info.si_signo); 1262 else 1263 uap->sysmsg_result = info.si_signo; 1264 return (error); 1265 } 1266 1267 int 1268 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1269 { 1270 siginfo_t info; 1271 sigset_t set; 1272 int error; 1273 1274 error = copyin(uap->set, &set, sizeof(set)); 1275 if (error) 1276 return (error); 1277 error = kern_sigtimedwait(set, &info, NULL); 1278 if (error) 1279 return (error); 1280 if (uap->info) 1281 error = copyout(&info, uap->info, sizeof(info)); 1282 /* Repost if we got an error. */ 1283 if (error) 1284 ksignal(curproc, info.si_signo); 1285 else 1286 uap->sysmsg_result = info.si_signo; 1287 return (error); 1288 } 1289 1290 /* 1291 * If the current process has received a signal that would interrupt a 1292 * system call, return EINTR or ERESTART as appropriate. 1293 */ 1294 int 1295 iscaught(struct lwp *lp) 1296 { 1297 struct proc *p = lp->lwp_proc; 1298 int sig; 1299 1300 if (p) { 1301 if ((sig = CURSIG(lp)) != 0) { 1302 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1303 return (EINTR); 1304 return (ERESTART); 1305 } 1306 } 1307 return(EWOULDBLOCK); 1308 } 1309 1310 /* 1311 * If the current process has received a signal (should be caught or cause 1312 * termination, should interrupt current syscall), return the signal number. 1313 * Stop signals with default action are processed immediately, then cleared; 1314 * they aren't returned. This is checked after each entry to the system for 1315 * a syscall or trap (though this can usually be done without calling issignal 1316 * by checking the pending signal masks in the CURSIG macro.) The normal call 1317 * sequence is 1318 * 1319 * This routine is called via CURSIG/__cursig and the MP lock might not be 1320 * held. Obtain the MP lock for the duration of the operation. 1321 * 1322 * while (sig = CURSIG(curproc)) 1323 * postsig(sig); 1324 */ 1325 int 1326 issignal(struct lwp *lp) 1327 { 1328 struct proc *p = lp->lwp_proc; 1329 sigset_t mask; 1330 int sig, prop; 1331 1332 get_mplock(); 1333 for (;;) { 1334 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); 1335 1336 mask = p->p_siglist; 1337 SIGSETNAND(mask, lp->lwp_sigmask); 1338 if (p->p_flag & P_PPWAIT) 1339 SIG_STOPSIGMASK(mask); 1340 if (!SIGNOTEMPTY(mask)) { /* no signal to send */ 1341 rel_mplock(); 1342 return (0); 1343 } 1344 sig = sig_ffs(&mask); 1345 1346 STOPEVENT(p, S_SIG, sig); 1347 1348 /* 1349 * We should see pending but ignored signals 1350 * only if P_TRACED was on when they were posted. 1351 */ 1352 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 1353 SIGDELSET(p->p_siglist, sig); 1354 continue; 1355 } 1356 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) { 1357 /* 1358 * If traced, always stop, and stay stopped until 1359 * released by the parent. 1360 * 1361 * NOTE: SSTOP may get cleared during the loop, 1362 * but we do not re-notify the parent if we have 1363 * to loop several times waiting for the parent 1364 * to let us continue. 1365 * 1366 * XXX not sure if this is still true 1367 */ 1368 p->p_xstat = sig; 1369 proc_stop(p, 2); 1370 do { 1371 tstop(); 1372 } while (!trace_req(p) && (p->p_flag & P_TRACED)); 1373 1374 /* 1375 * If parent wants us to take the signal, 1376 * then it will leave it in p->p_xstat; 1377 * otherwise we just look for signals again. 1378 */ 1379 SIGDELSET(p->p_siglist, sig); /* clear old signal */ 1380 sig = p->p_xstat; 1381 if (sig == 0) 1382 continue; 1383 1384 /* 1385 * Put the new signal into p_siglist. If the 1386 * signal is being masked, look for other signals. 1387 */ 1388 SIGADDSET(p->p_siglist, sig); 1389 if (SIGISMEMBER(lp->lwp_sigmask, sig)) 1390 continue; 1391 1392 /* 1393 * If the traced bit got turned off, go back up 1394 * to the top to rescan signals. This ensures 1395 * that p_sig* and ps_sigact are consistent. 1396 */ 1397 if ((p->p_flag & P_TRACED) == 0) 1398 continue; 1399 } 1400 1401 prop = sigprop(sig); 1402 1403 /* 1404 * Decide whether the signal should be returned. 1405 * Return the signal's number, or fall through 1406 * to clear it from the pending mask. 1407 */ 1408 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 1409 case (int)SIG_DFL: 1410 /* 1411 * Don't take default actions on system processes. 1412 */ 1413 if (p->p_pid <= 1) { 1414 #ifdef DIAGNOSTIC 1415 /* 1416 * Are you sure you want to ignore SIGSEGV 1417 * in init? XXX 1418 */ 1419 kprintf("Process (pid %lu) got signal %d\n", 1420 (u_long)p->p_pid, sig); 1421 #endif 1422 break; /* == ignore */ 1423 } 1424 1425 /* 1426 * Handle the in-kernel checkpoint action 1427 */ 1428 if (prop & SA_CKPT) { 1429 checkpoint_signal_handler(p); 1430 break; 1431 } 1432 1433 /* 1434 * If there is a pending stop signal to process 1435 * with default action, stop here, 1436 * then clear the signal. However, 1437 * if process is member of an orphaned 1438 * process group, ignore tty stop signals. 1439 */ 1440 if (prop & SA_STOP) { 1441 if (p->p_flag & P_TRACED || 1442 (p->p_pgrp->pg_jobc == 0 && 1443 prop & SA_TTYSTOP)) 1444 break; /* == ignore */ 1445 p->p_xstat = sig; 1446 proc_stop(p, 1); 1447 while (p->p_stat == SSTOP) { 1448 tstop(); 1449 } 1450 break; 1451 } else if (prop & SA_IGNORE) { 1452 /* 1453 * Except for SIGCONT, shouldn't get here. 1454 * Default action is to ignore; drop it. 1455 */ 1456 break; /* == ignore */ 1457 } else { 1458 rel_mplock(); 1459 return (sig); 1460 } 1461 1462 /*NOTREACHED*/ 1463 1464 case (int)SIG_IGN: 1465 /* 1466 * Masking above should prevent us ever trying 1467 * to take action on an ignored signal other 1468 * than SIGCONT, unless process is traced. 1469 */ 1470 if ((prop & SA_CONT) == 0 && 1471 (p->p_flag & P_TRACED) == 0) 1472 kprintf("issignal\n"); 1473 break; /* == ignore */ 1474 1475 default: 1476 /* 1477 * This signal has an action, let 1478 * postsig() process it. 1479 */ 1480 rel_mplock(); 1481 return (sig); 1482 } 1483 SIGDELSET(p->p_siglist, sig); /* take the signal! */ 1484 } 1485 /* NOTREACHED */ 1486 } 1487 1488 /* 1489 * Take the action for the specified signal 1490 * from the current set of pending signals. 1491 */ 1492 void 1493 postsig(int sig) 1494 { 1495 struct lwp *lp = curthread->td_lwp; 1496 struct proc *p = lp->lwp_proc; 1497 struct sigacts *ps = p->p_sigacts; 1498 sig_t action; 1499 sigset_t returnmask; 1500 int code; 1501 1502 KASSERT(sig != 0, ("postsig")); 1503 1504 /* 1505 * If we are a virtual kernel running an emulated user process 1506 * context, switch back to the virtual kernel context before 1507 * trying to post the signal. 1508 */ 1509 if (p->p_vkernel && p->p_vkernel->vk_current) { 1510 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs; 1511 tf->tf_trapno = 0; 1512 vkernel_trap(p, tf); 1513 } 1514 1515 SIGDELSET(p->p_siglist, sig); 1516 action = ps->ps_sigact[_SIG_IDX(sig)]; 1517 #ifdef KTRACE 1518 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 1519 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ? 1520 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 1521 #endif 1522 STOPEVENT(p, S_SIG, sig); 1523 1524 if (action == SIG_DFL) { 1525 /* 1526 * Default action, where the default is to kill 1527 * the process. (Other cases were ignored above.) 1528 */ 1529 sigexit(p, sig); 1530 /* NOTREACHED */ 1531 } else { 1532 /* 1533 * If we get here, the signal must be caught. 1534 */ 1535 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 1536 ("postsig action")); 1537 1538 crit_enter(); 1539 1540 /* 1541 * Reset the signal handler if asked to 1542 */ 1543 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 1544 /* 1545 * See kern_sigaction() for origin of this code. 1546 */ 1547 SIGDELSET(p->p_sigcatch, sig); 1548 if (sig != SIGCONT && 1549 sigprop(sig) & SA_IGNORE) 1550 SIGADDSET(p->p_sigignore, sig); 1551 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 1552 } 1553 1554 /* 1555 * Handle the mailbox case. Copyout to the appropriate 1556 * location but do not generate a signal frame. The system 1557 * call simply returns EINTR and the user is responsible for 1558 * polling the mailbox. 1559 */ 1560 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) { 1561 int sig_copy = sig; 1562 copyout(&sig_copy, (void *)action, sizeof(int)); 1563 curproc->p_flag |= P_MAILBOX; 1564 crit_exit(); 1565 goto done; 1566 } 1567 1568 /* 1569 * Set the signal mask and calculate the mask to restore 1570 * when the signal function returns. 1571 * 1572 * Special case: user has done a sigsuspend. Here the 1573 * current mask is not of interest, but rather the 1574 * mask from before the sigsuspend is what we want 1575 * restored after the signal processing is completed. 1576 */ 1577 if (lp->lwp_flag & LWP_OLDMASK) { 1578 returnmask = lp->lwp_oldsigmask; 1579 lp->lwp_flag &= ~LWP_OLDMASK; 1580 } else { 1581 returnmask = lp->lwp_sigmask; 1582 } 1583 1584 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 1585 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 1586 SIGADDSET(lp->lwp_sigmask, sig); 1587 1588 crit_exit(); 1589 lp->lwp_ru.ru_nsignals++; 1590 if (p->p_sig != sig) { 1591 code = 0; 1592 } else { 1593 code = p->p_code; 1594 p->p_code = 0; 1595 p->p_sig = 0; 1596 } 1597 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 1598 } 1599 done: 1600 ; 1601 } 1602 1603 /* 1604 * Kill the current process for stated reason. 1605 */ 1606 void 1607 killproc(struct proc *p, char *why) 1608 { 1609 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 1610 p->p_pid, p->p_comm, 1611 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 1612 ksignal(p, SIGKILL); 1613 } 1614 1615 /* 1616 * Force the current process to exit with the specified signal, dumping core 1617 * if appropriate. We bypass the normal tests for masked and caught signals, 1618 * allowing unrecoverable failures to terminate the process without changing 1619 * signal state. Mark the accounting record with the signal termination. 1620 * If dumping core, save the signal number for the debugger. Calls exit and 1621 * does not return. 1622 */ 1623 void 1624 sigexit(struct proc *p, int sig) 1625 { 1626 p->p_acflag |= AXSIG; 1627 if (sigprop(sig) & SA_CORE) { 1628 p->p_sig = sig; 1629 /* 1630 * Log signals which would cause core dumps 1631 * (Log as LOG_INFO to appease those who don't want 1632 * these messages.) 1633 * XXX : Todo, as well as euid, write out ruid too 1634 */ 1635 if (coredump(p) == 0) 1636 sig |= WCOREFLAG; 1637 if (kern_logsigexit) 1638 log(LOG_INFO, 1639 "pid %d (%s), uid %d: exited on signal %d%s\n", 1640 p->p_pid, p->p_comm, 1641 p->p_ucred ? p->p_ucred->cr_uid : -1, 1642 sig &~ WCOREFLAG, 1643 sig & WCOREFLAG ? " (core dumped)" : ""); 1644 } 1645 exit1(W_EXITCODE(0, sig)); 1646 /* NOTREACHED */ 1647 } 1648 1649 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 1650 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 1651 sizeof(corefilename), "process corefile name format string"); 1652 1653 /* 1654 * expand_name(name, uid, pid) 1655 * Expand the name described in corefilename, using name, uid, and pid. 1656 * corefilename is a kprintf-like string, with three format specifiers: 1657 * %N name of process ("name") 1658 * %P process id (pid) 1659 * %U user id (uid) 1660 * For example, "%N.core" is the default; they can be disabled completely 1661 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 1662 * This is controlled by the sysctl variable kern.corefile (see above). 1663 */ 1664 1665 static char * 1666 expand_name(const char *name, uid_t uid, pid_t pid) 1667 { 1668 char *temp; 1669 char buf[11]; /* Buffer for pid/uid -- max 4B */ 1670 int i, n; 1671 char *format = corefilename; 1672 size_t namelen; 1673 1674 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 1675 if (temp == NULL) 1676 return NULL; 1677 namelen = strlen(name); 1678 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 1679 int l; 1680 switch (format[i]) { 1681 case '%': /* Format character */ 1682 i++; 1683 switch (format[i]) { 1684 case '%': 1685 temp[n++] = '%'; 1686 break; 1687 case 'N': /* process name */ 1688 if ((n + namelen) > MAXPATHLEN) { 1689 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1690 pid, name, uid, temp, name); 1691 kfree(temp, M_TEMP); 1692 return NULL; 1693 } 1694 memcpy(temp+n, name, namelen); 1695 n += namelen; 1696 break; 1697 case 'P': /* process id */ 1698 l = ksprintf(buf, "%u", pid); 1699 if ((n + l) > MAXPATHLEN) { 1700 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1701 pid, name, uid, temp, name); 1702 kfree(temp, M_TEMP); 1703 return NULL; 1704 } 1705 memcpy(temp+n, buf, l); 1706 n += l; 1707 break; 1708 case 'U': /* user id */ 1709 l = ksprintf(buf, "%u", uid); 1710 if ((n + l) > MAXPATHLEN) { 1711 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 1712 pid, name, uid, temp, name); 1713 kfree(temp, M_TEMP); 1714 return NULL; 1715 } 1716 memcpy(temp+n, buf, l); 1717 n += l; 1718 break; 1719 default: 1720 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 1721 } 1722 break; 1723 default: 1724 temp[n++] = format[i]; 1725 } 1726 } 1727 temp[n] = '\0'; 1728 return temp; 1729 } 1730 1731 /* 1732 * Dump a process' core. The main routine does some 1733 * policy checking, and creates the name of the coredump; 1734 * then it passes on a vnode and a size limit to the process-specific 1735 * coredump routine if there is one; if there _is not_ one, it returns 1736 * ENOSYS; otherwise it returns the error from the process-specific routine. 1737 */ 1738 1739 static int 1740 coredump(struct proc *p) 1741 { 1742 struct vnode *vp; 1743 struct ucred *cred = p->p_ucred; 1744 struct flock lf; 1745 struct nlookupdata nd; 1746 struct vattr vattr; 1747 int error, error1; 1748 char *name; /* name of corefile */ 1749 off_t limit; 1750 1751 STOPEVENT(p, S_CORE, 0); 1752 1753 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) 1754 return (EFAULT); 1755 1756 /* 1757 * Note that the bulk of limit checking is done after 1758 * the corefile is created. The exception is if the limit 1759 * for corefiles is 0, in which case we don't bother 1760 * creating the corefile at all. This layout means that 1761 * a corefile is truncated instead of not being created, 1762 * if it is larger than the limit. 1763 */ 1764 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 1765 if (limit == 0) 1766 return EFBIG; 1767 1768 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 1769 if (name == NULL) 1770 return (EINVAL); 1771 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 1772 if (error == 0) 1773 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); 1774 kfree(name, M_TEMP); 1775 if (error) { 1776 nlookup_done(&nd); 1777 return (error); 1778 } 1779 vp = nd.nl_open_vp; 1780 nd.nl_open_vp = NULL; 1781 nlookup_done(&nd); 1782 1783 vn_unlock(vp); 1784 lf.l_whence = SEEK_SET; 1785 lf.l_start = 0; 1786 lf.l_len = 0; 1787 lf.l_type = F_WRLCK; 1788 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 1789 if (error) 1790 goto out2; 1791 1792 /* Don't dump to non-regular files or files with links. */ 1793 if (vp->v_type != VREG || 1794 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 1795 error = EFAULT; 1796 goto out1; 1797 } 1798 1799 VATTR_NULL(&vattr); 1800 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1801 vattr.va_size = 0; 1802 VOP_SETATTR(vp, &vattr, cred); 1803 p->p_acflag |= ACORE; 1804 vn_unlock(vp); 1805 1806 error = p->p_sysent->sv_coredump ? 1807 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; 1808 1809 out1: 1810 lf.l_type = F_UNLCK; 1811 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 1812 out2: 1813 error1 = vn_close(vp, FWRITE); 1814 if (error == 0) 1815 error = error1; 1816 return (error); 1817 } 1818 1819 /* 1820 * Nonexistent system call-- signal process (may want to handle it). 1821 * Flag error in case process won't see signal immediately (blocked or ignored). 1822 */ 1823 /* ARGSUSED */ 1824 int 1825 sys_nosys(struct nosys_args *args) 1826 { 1827 ksignal(curproc, SIGSYS); 1828 return (EINVAL); 1829 } 1830 1831 /* 1832 * Send a SIGIO or SIGURG signal to a process or process group using 1833 * stored credentials rather than those of the current process. 1834 */ 1835 void 1836 pgsigio(struct sigio *sigio, int sig, int checkctty) 1837 { 1838 if (sigio == NULL) 1839 return; 1840 1841 if (sigio->sio_pgid > 0) { 1842 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 1843 sigio->sio_proc)) 1844 ksignal(sigio->sio_proc, sig); 1845 } else if (sigio->sio_pgid < 0) { 1846 struct proc *p; 1847 1848 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE); 1849 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { 1850 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 1851 (checkctty == 0 || (p->p_flag & P_CONTROLT))) 1852 ksignal(p, sig); 1853 } 1854 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE); 1855 } 1856 } 1857 1858 static int 1859 filt_sigattach(struct knote *kn) 1860 { 1861 struct proc *p = curproc; 1862 1863 kn->kn_ptr.p_proc = p; 1864 kn->kn_flags |= EV_CLEAR; /* automatically set */ 1865 1866 /* XXX lock the proc here while adding to the list? */ 1867 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); 1868 1869 return (0); 1870 } 1871 1872 static void 1873 filt_sigdetach(struct knote *kn) 1874 { 1875 struct proc *p = kn->kn_ptr.p_proc; 1876 1877 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); 1878 } 1879 1880 /* 1881 * signal knotes are shared with proc knotes, so we apply a mask to 1882 * the hint in order to differentiate them from process hints. This 1883 * could be avoided by using a signal-specific knote list, but probably 1884 * isn't worth the trouble. 1885 */ 1886 static int 1887 filt_signal(struct knote *kn, long hint) 1888 { 1889 if (hint & NOTE_SIGNAL) { 1890 hint &= ~NOTE_SIGNAL; 1891 1892 if (kn->kn_id == hint) 1893 kn->kn_data++; 1894 } 1895 return (kn->kn_data != 0); 1896 } 1897