1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 35 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ 36 */ 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/sysproto.h> 44 #include <sys/signalvar.h> 45 #include <sys/resourcevar.h> 46 #include <sys/vnode.h> 47 #include <sys/event.h> 48 #include <sys/proc.h> 49 #include <sys/nlookup.h> 50 #include <sys/pioctl.h> 51 #include <sys/acct.h> 52 #include <sys/fcntl.h> 53 #include <sys/lock.h> 54 #include <sys/wait.h> 55 #include <sys/ktrace.h> 56 #include <sys/syslog.h> 57 #include <sys/stat.h> 58 #include <sys/sysent.h> 59 #include <sys/sysctl.h> 60 #include <sys/malloc.h> 61 #include <sys/interrupt.h> 62 #include <sys/unistd.h> 63 #include <sys/kern_syscall.h> 64 #include <sys/vkernel.h> 65 66 #include <sys/signal2.h> 67 #include <sys/thread2.h> 68 #include <sys/spinlock2.h> 69 70 #include <machine/cpu.h> 71 #include <machine/smp.h> 72 73 static int coredump(struct lwp *, int); 74 static char *expand_name(const char *, uid_t, pid_t); 75 static int dokillpg(int sig, int pgid, int all); 76 static int sig_ffs(sigset_t *set); 77 static int sigprop(int sig); 78 static void lwp_signotify(struct lwp *lp); 79 static void lwp_signotify_remote(void *arg); 80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info, 81 struct timespec *timeout); 82 static void proc_stopwait(struct proc *p); 83 84 static int filt_sigattach(struct knote *kn); 85 static void filt_sigdetach(struct knote *kn); 86 static int filt_signal(struct knote *kn, long hint); 87 88 struct filterops sig_filtops = 89 { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, filt_signal }; 90 91 static int kern_logsigexit = 1; 92 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 93 &kern_logsigexit, 0, 94 "Log processes quitting on abnormal signals to syslog(3)"); 95 96 /* 97 * Can process p send the signal sig to process q? Only processes within 98 * the current reaper or children of the current reaper can be signaled. 99 * Normally the reaper itself cannot be signalled, unless initok is set. 100 */ 101 #define CANSIGNAL(q, sig, initok) \ 102 ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \ 103 reaper_sigtest(curproc, p, initok)) || \ 104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) 105 106 /* 107 * Policy -- Can real uid ruid with ucred uc send a signal to process q? 108 */ 109 #define CANSIGIO(ruid, uc, q) \ 110 ((uc)->cr_uid == 0 || \ 111 (ruid) == (q)->p_ucred->cr_ruid || \ 112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ 113 (ruid) == (q)->p_ucred->cr_uid || \ 114 (uc)->cr_uid == (q)->p_ucred->cr_uid) 115 116 int sugid_coredump; 117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); 119 120 static int do_coredump = 1; 121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, 122 &do_coredump, 0, "Enable/Disable coredumps"); 123 124 /* 125 * Signal properties and actions. 126 * The array below categorizes the signals and their default actions 127 * according to the following properties: 128 */ 129 #define SA_KILL 0x01 /* terminates process by default */ 130 #define SA_CORE 0x02 /* ditto and coredumps */ 131 #define SA_STOP 0x04 /* suspend process */ 132 #define SA_TTYSTOP 0x08 /* ditto, from tty */ 133 #define SA_IGNORE 0x10 /* ignore by default */ 134 #define SA_CONT 0x20 /* continue if suspended */ 135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */ 136 #define SA_CKPT 0x80 /* checkpoint process */ 137 138 139 static int sigproptbl[NSIG] = { 140 SA_KILL, /* SIGHUP */ 141 SA_KILL, /* SIGINT */ 142 SA_KILL|SA_CORE, /* SIGQUIT */ 143 SA_KILL|SA_CORE, /* SIGILL */ 144 SA_KILL|SA_CORE, /* SIGTRAP */ 145 SA_KILL|SA_CORE, /* SIGABRT */ 146 SA_KILL|SA_CORE, /* SIGEMT */ 147 SA_KILL|SA_CORE, /* SIGFPE */ 148 SA_KILL, /* SIGKILL */ 149 SA_KILL|SA_CORE, /* SIGBUS */ 150 SA_KILL|SA_CORE, /* SIGSEGV */ 151 SA_KILL|SA_CORE, /* SIGSYS */ 152 SA_KILL, /* SIGPIPE */ 153 SA_KILL, /* SIGALRM */ 154 SA_KILL, /* SIGTERM */ 155 SA_IGNORE, /* SIGURG */ 156 SA_STOP, /* SIGSTOP */ 157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */ 158 SA_IGNORE|SA_CONT, /* SIGCONT */ 159 SA_IGNORE, /* SIGCHLD */ 160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */ 161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */ 162 SA_IGNORE, /* SIGIO */ 163 SA_KILL, /* SIGXCPU */ 164 SA_KILL, /* SIGXFSZ */ 165 SA_KILL, /* SIGVTALRM */ 166 SA_KILL, /* SIGPROF */ 167 SA_IGNORE, /* SIGWINCH */ 168 SA_IGNORE, /* SIGINFO */ 169 SA_KILL, /* SIGUSR1 */ 170 SA_KILL, /* SIGUSR2 */ 171 SA_IGNORE, /* SIGTHR */ 172 SA_CKPT, /* SIGCKPT */ 173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ 174 SA_IGNORE, 175 SA_IGNORE, 176 SA_IGNORE, 177 SA_IGNORE, 178 SA_IGNORE, 179 SA_IGNORE, 180 SA_IGNORE, 181 SA_IGNORE, 182 SA_IGNORE, 183 SA_IGNORE, 184 SA_IGNORE, 185 SA_IGNORE, 186 SA_IGNORE, 187 SA_IGNORE, 188 SA_IGNORE, 189 SA_IGNORE, 190 SA_IGNORE, 191 SA_IGNORE, 192 SA_IGNORE, 193 SA_IGNORE, 194 SA_IGNORE, 195 SA_IGNORE, 196 SA_IGNORE, 197 SA_IGNORE, 198 SA_IGNORE, 199 SA_IGNORE, 200 SA_IGNORE, 201 SA_IGNORE, 202 SA_IGNORE, 203 SA_IGNORE, 204 205 }; 206 207 static __inline int 208 sigprop(int sig) 209 { 210 211 if (sig > 0 && sig < NSIG) 212 return (sigproptbl[_SIG_IDX(sig)]); 213 return (0); 214 } 215 216 static __inline int 217 sig_ffs(sigset_t *set) 218 { 219 int i; 220 221 for (i = 0; i < _SIG_WORDS; i++) 222 if (set->__bits[i]) 223 return (ffs(set->__bits[i]) + (i * 32)); 224 return (0); 225 } 226 227 /* 228 * Allows us to populate siginfo->si_pid and si_uid in the target process 229 * (p) from the originating thread (td). This function must work properly 230 * even if a kernel thread is sending the signal. 231 * 232 * NOTE: Signals are not queued, so if multiple signals are received the 233 * signal handler will only see the most recent pid and uid for any 234 * given signal number. 235 */ 236 static __inline void 237 sigsetfrompid(thread_t td, struct proc *p, int sig) 238 { 239 struct sigacts *sap; 240 241 if ((sap = p->p_sigacts) == NULL) 242 return; 243 if (td->td_proc) { 244 sap->ps_frominfo[sig].pid = td->td_proc->p_pid; 245 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid; 246 } else { 247 sap->ps_frominfo[sig].pid = 0; 248 sap->ps_frominfo[sig].uid = 0; 249 } 250 } 251 252 /* 253 * No requirements. 254 */ 255 int 256 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 257 { 258 struct thread *td = curthread; 259 struct proc *p = td->td_proc; 260 struct lwp *lp; 261 struct sigacts *ps = p->p_sigacts; 262 263 if (sig <= 0 || sig > _SIG_MAXSIG) 264 return (EINVAL); 265 266 lwkt_gettoken(&p->p_token); 267 268 if (oact) { 269 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 270 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 271 oact->sa_flags = 0; 272 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 273 oact->sa_flags |= SA_ONSTACK; 274 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 275 oact->sa_flags |= SA_RESTART; 276 if (SIGISMEMBER(ps->ps_sigreset, sig)) 277 oact->sa_flags |= SA_RESETHAND; 278 if (SIGISMEMBER(ps->ps_signodefer, sig)) 279 oact->sa_flags |= SA_NODEFER; 280 if (SIGISMEMBER(ps->ps_siginfo, sig)) 281 oact->sa_flags |= SA_SIGINFO; 282 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 283 oact->sa_flags |= SA_NOCLDSTOP; 284 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 285 oact->sa_flags |= SA_NOCLDWAIT; 286 } 287 if (act) { 288 /* 289 * Check for invalid requests. KILL and STOP cannot be 290 * caught. 291 */ 292 if (sig == SIGKILL || sig == SIGSTOP) { 293 if (act->sa_handler != SIG_DFL) { 294 lwkt_reltoken(&p->p_token); 295 return (EINVAL); 296 } 297 } 298 299 /* 300 * Change setting atomically. 301 */ 302 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 303 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 304 if (act->sa_flags & SA_SIGINFO) { 305 ps->ps_sigact[_SIG_IDX(sig)] = 306 (__sighandler_t *)act->sa_sigaction; 307 SIGADDSET(ps->ps_siginfo, sig); 308 } else { 309 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 310 SIGDELSET(ps->ps_siginfo, sig); 311 } 312 if (!(act->sa_flags & SA_RESTART)) 313 SIGADDSET(ps->ps_sigintr, sig); 314 else 315 SIGDELSET(ps->ps_sigintr, sig); 316 if (act->sa_flags & SA_ONSTACK) 317 SIGADDSET(ps->ps_sigonstack, sig); 318 else 319 SIGDELSET(ps->ps_sigonstack, sig); 320 if (act->sa_flags & SA_RESETHAND) 321 SIGADDSET(ps->ps_sigreset, sig); 322 else 323 SIGDELSET(ps->ps_sigreset, sig); 324 if (act->sa_flags & SA_NODEFER) 325 SIGADDSET(ps->ps_signodefer, sig); 326 else 327 SIGDELSET(ps->ps_signodefer, sig); 328 if (sig == SIGCHLD) { 329 if (act->sa_flags & SA_NOCLDSTOP) 330 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 331 else 332 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 333 if (act->sa_flags & SA_NOCLDWAIT) { 334 /* 335 * Paranoia: since SA_NOCLDWAIT is implemented 336 * by reparenting the dying child to PID 1 (and 337 * trust it to reap the zombie), PID 1 itself 338 * is forbidden to set SA_NOCLDWAIT. 339 */ 340 if (p->p_pid == 1) 341 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 342 else 343 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 344 } else { 345 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 346 } 347 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 348 ps->ps_flag |= PS_CLDSIGIGN; 349 else 350 ps->ps_flag &= ~PS_CLDSIGIGN; 351 } 352 /* 353 * Set bit in p_sigignore for signals that are set to SIG_IGN, 354 * and for signals set to SIG_DFL where the default is to 355 * ignore. However, don't put SIGCONT in p_sigignore, as we 356 * have to restart the process. 357 * 358 * Also remove the signal from the process and lwp signal 359 * list. 360 */ 361 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 362 (sigprop(sig) & SA_IGNORE && 363 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 364 SIGDELSET_ATOMIC(p->p_siglist, sig); 365 FOREACH_LWP_IN_PROC(lp, p) { 366 spin_lock(&lp->lwp_spin); 367 SIGDELSET(lp->lwp_siglist, sig); 368 spin_unlock(&lp->lwp_spin); 369 } 370 if (sig != SIGCONT) { 371 /* easier in ksignal */ 372 SIGADDSET(p->p_sigignore, sig); 373 } 374 SIGDELSET(p->p_sigcatch, sig); 375 } else { 376 SIGDELSET(p->p_sigignore, sig); 377 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 378 SIGDELSET(p->p_sigcatch, sig); 379 else 380 SIGADDSET(p->p_sigcatch, sig); 381 } 382 } 383 lwkt_reltoken(&p->p_token); 384 return (0); 385 } 386 387 int 388 sys_sigaction(struct sigaction_args *uap) 389 { 390 struct sigaction act, oact; 391 struct sigaction *actp, *oactp; 392 int error; 393 394 actp = (uap->act != NULL) ? &act : NULL; 395 oactp = (uap->oact != NULL) ? &oact : NULL; 396 if (actp) { 397 error = copyin(uap->act, actp, sizeof(act)); 398 if (error) 399 return (error); 400 } 401 error = kern_sigaction(uap->sig, actp, oactp); 402 if (oactp && !error) { 403 error = copyout(oactp, uap->oact, sizeof(oact)); 404 } 405 return (error); 406 } 407 408 /* 409 * Initialize signal state for process 0; 410 * set to ignore signals that are ignored by default. 411 */ 412 void 413 siginit(struct proc *p) 414 { 415 int i; 416 417 for (i = 1; i <= NSIG; i++) 418 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 419 SIGADDSET(p->p_sigignore, i); 420 } 421 422 /* 423 * Reset signals for an exec of the specified process. 424 */ 425 void 426 execsigs(struct proc *p) 427 { 428 struct sigacts *ps = p->p_sigacts; 429 struct lwp *lp; 430 int sig; 431 432 lp = ONLY_LWP_IN_PROC(p); 433 434 /* 435 * Reset caught signals. Held signals remain held 436 * through p_sigmask (unless they were caught, 437 * and are now ignored by default). 438 */ 439 while (SIGNOTEMPTY(p->p_sigcatch)) { 440 sig = sig_ffs(&p->p_sigcatch); 441 SIGDELSET(p->p_sigcatch, sig); 442 if (sigprop(sig) & SA_IGNORE) { 443 if (sig != SIGCONT) 444 SIGADDSET(p->p_sigignore, sig); 445 SIGDELSET_ATOMIC(p->p_siglist, sig); 446 /* don't need spinlock */ 447 SIGDELSET(lp->lwp_siglist, sig); 448 } 449 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 450 } 451 452 /* 453 * Reset stack state to the user stack. 454 * Clear set of signals caught on the signal stack. 455 */ 456 lp->lwp_sigstk.ss_flags = SS_DISABLE; 457 lp->lwp_sigstk.ss_size = 0; 458 lp->lwp_sigstk.ss_sp = NULL; 459 lp->lwp_flags &= ~LWP_ALTSTACK; 460 /* 461 * Reset no zombies if child dies flag as Solaris does. 462 */ 463 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 464 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 465 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 466 } 467 468 /* 469 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 470 * 471 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 472 * p == curproc. 473 */ 474 int 475 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 476 { 477 struct thread *td = curthread; 478 struct lwp *lp = td->td_lwp; 479 struct proc *p = td->td_proc; 480 int error; 481 482 lwkt_gettoken(&p->p_token); 483 484 if (oset != NULL) 485 *oset = lp->lwp_sigmask; 486 487 error = 0; 488 if (set != NULL) { 489 switch (how) { 490 case SIG_BLOCK: 491 SIG_CANTMASK(*set); 492 SIGSETOR(lp->lwp_sigmask, *set); 493 break; 494 case SIG_UNBLOCK: 495 SIGSETNAND(lp->lwp_sigmask, *set); 496 break; 497 case SIG_SETMASK: 498 SIG_CANTMASK(*set); 499 lp->lwp_sigmask = *set; 500 break; 501 default: 502 error = EINVAL; 503 break; 504 } 505 } 506 507 lwkt_reltoken(&p->p_token); 508 509 return (error); 510 } 511 512 /* 513 * sigprocmask() 514 * 515 * MPSAFE 516 */ 517 int 518 sys_sigprocmask(struct sigprocmask_args *uap) 519 { 520 sigset_t set, oset; 521 sigset_t *setp, *osetp; 522 int error; 523 524 setp = (uap->set != NULL) ? &set : NULL; 525 osetp = (uap->oset != NULL) ? &oset : NULL; 526 if (setp) { 527 error = copyin(uap->set, setp, sizeof(set)); 528 if (error) 529 return (error); 530 } 531 error = kern_sigprocmask(uap->how, setp, osetp); 532 if (osetp && !error) { 533 error = copyout(osetp, uap->oset, sizeof(oset)); 534 } 535 return (error); 536 } 537 538 /* 539 * MPSAFE 540 */ 541 int 542 kern_sigpending(sigset_t *set) 543 { 544 struct lwp *lp = curthread->td_lwp; 545 546 *set = lwp_sigpend(lp); 547 548 return (0); 549 } 550 551 /* 552 * MPSAFE 553 */ 554 int 555 sys_sigpending(struct sigpending_args *uap) 556 { 557 sigset_t set; 558 int error; 559 560 error = kern_sigpending(&set); 561 562 if (error == 0) 563 error = copyout(&set, uap->set, sizeof(set)); 564 return (error); 565 } 566 567 /* 568 * Suspend process until signal, providing mask to be set 569 * in the meantime. 570 * 571 * MPSAFE 572 */ 573 int 574 kern_sigsuspend(sigset_t *set) 575 { 576 struct thread *td = curthread; 577 struct lwp *lp = td->td_lwp; 578 struct proc *p = td->td_proc; 579 struct sigacts *ps = p->p_sigacts; 580 581 /* 582 * When returning from sigsuspend, we want 583 * the old mask to be restored after the 584 * signal handler has finished. Thus, we 585 * save it here and mark the sigacts structure 586 * to indicate this. 587 */ 588 lp->lwp_oldsigmask = lp->lwp_sigmask; 589 lp->lwp_flags |= LWP_OLDMASK; 590 591 SIG_CANTMASK(*set); 592 lp->lwp_sigmask = *set; 593 while (tsleep(ps, PCATCH, "pause", 0) == 0) 594 /* void */; 595 /* always return EINTR rather than ERESTART... */ 596 return (EINTR); 597 } 598 599 /* 600 * Note nonstandard calling convention: libc stub passes mask, not 601 * pointer, to save a copyin. 602 * 603 * MPSAFE 604 */ 605 int 606 sys_sigsuspend(struct sigsuspend_args *uap) 607 { 608 sigset_t mask; 609 int error; 610 611 error = copyin(uap->sigmask, &mask, sizeof(mask)); 612 if (error) 613 return (error); 614 615 error = kern_sigsuspend(&mask); 616 617 return (error); 618 } 619 620 /* 621 * MPSAFE 622 */ 623 int 624 kern_sigaltstack(stack_t *ss, stack_t *oss) 625 { 626 struct thread *td = curthread; 627 struct lwp *lp = td->td_lwp; 628 struct proc *p = td->td_proc; 629 630 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 631 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 632 633 if (oss) 634 *oss = lp->lwp_sigstk; 635 636 if (ss) { 637 if (ss->ss_flags & ~SS_DISABLE) 638 return (EINVAL); 639 if (ss->ss_flags & SS_DISABLE) { 640 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 641 return (EPERM); 642 lp->lwp_flags &= ~LWP_ALTSTACK; 643 lp->lwp_sigstk.ss_flags = ss->ss_flags; 644 } else { 645 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 646 return (ENOMEM); 647 lp->lwp_flags |= LWP_ALTSTACK; 648 lp->lwp_sigstk = *ss; 649 } 650 } 651 652 return (0); 653 } 654 655 /* 656 * MPSAFE 657 */ 658 int 659 sys_sigaltstack(struct sigaltstack_args *uap) 660 { 661 stack_t ss, oss; 662 int error; 663 664 if (uap->ss) { 665 error = copyin(uap->ss, &ss, sizeof(ss)); 666 if (error) 667 return (error); 668 } 669 670 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); 671 672 if (error == 0 && uap->oss) 673 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 674 return (error); 675 } 676 677 /* 678 * Common code for kill process group/broadcast kill. 679 * cp is calling process. 680 */ 681 struct killpg_info { 682 int nfound; 683 int sig; 684 }; 685 686 static int killpg_all_callback(struct proc *p, void *data); 687 688 static int 689 dokillpg(int sig, int pgid, int all) 690 { 691 struct killpg_info info; 692 struct proc *cp = curproc; 693 struct proc *p; 694 struct pgrp *pgrp; 695 696 info.nfound = 0; 697 info.sig = sig; 698 699 if (all) { 700 /* 701 * broadcast 702 */ 703 allproc_scan(killpg_all_callback, &info, 0); 704 } else { 705 if (pgid == 0) { 706 /* 707 * zero pgid means send to my process group. 708 */ 709 pgrp = cp->p_pgrp; 710 pgref(pgrp); 711 } else { 712 pgrp = pgfind(pgid); 713 if (pgrp == NULL) 714 return (ESRCH); 715 } 716 717 /* 718 * Must interlock all signals against fork 719 */ 720 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 721 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 722 if (p->p_pid <= 1 || 723 p->p_stat == SZOMB || 724 (p->p_flags & P_SYSTEM) || 725 !CANSIGNAL(p, sig, 0)) { 726 continue; 727 } 728 ++info.nfound; 729 if (sig) 730 ksignal(p, sig); 731 } 732 lockmgr(&pgrp->pg_lock, LK_RELEASE); 733 pgrel(pgrp); 734 } 735 return (info.nfound ? 0 : ESRCH); 736 } 737 738 static int 739 killpg_all_callback(struct proc *p, void *data) 740 { 741 struct killpg_info *info = data; 742 743 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 744 p == curproc || !CANSIGNAL(p, info->sig, 0)) { 745 return (0); 746 } 747 ++info->nfound; 748 if (info->sig) 749 ksignal(p, info->sig); 750 return(0); 751 } 752 753 /* 754 * Send a general signal to a process or LWPs within that process. 755 * 756 * Note that new signals cannot be sent if a process is exiting or already 757 * a zombie, but we return success anyway as userland is likely to not handle 758 * the race properly. 759 * 760 * No requirements. 761 */ 762 int 763 kern_kill(int sig, pid_t pid, lwpid_t tid) 764 { 765 int t; 766 767 if ((u_int)sig > _SIG_MAXSIG) 768 return (EINVAL); 769 770 if (pid > 0) { 771 struct proc *p; 772 struct lwp *lp = NULL; 773 774 /* 775 * Send a signal to a single process. If the kill() is 776 * racing an exiting process which has not yet been reaped 777 * act as though the signal was delivered successfully but 778 * don't actually try to deliver the signal. 779 */ 780 if ((p = pfind(pid)) == NULL) { 781 if ((p = zpfind(pid)) == NULL) 782 return (ESRCH); 783 PRELE(p); 784 return (0); 785 } 786 if (p != curproc) { 787 lwkt_gettoken_shared(&p->p_token); 788 if (!CANSIGNAL(p, sig, 1)) { 789 lwkt_reltoken(&p->p_token); 790 PRELE(p); 791 return (EPERM); 792 } 793 lwkt_reltoken(&p->p_token); 794 } 795 796 /* 797 * NOP if the process is exiting. Note that lwpsignal() is 798 * called directly with P_WEXIT set to kill individual LWPs 799 * during exit, which is allowed. 800 */ 801 if (p->p_flags & P_WEXIT) { 802 PRELE(p); 803 return (0); 804 } 805 if (tid != -1) { 806 lwkt_gettoken_shared(&p->p_token); 807 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 808 if (lp == NULL) { 809 lwkt_reltoken(&p->p_token); 810 PRELE(p); 811 return (ESRCH); 812 } 813 LWPHOLD(lp); 814 lwkt_reltoken(&p->p_token); 815 } 816 if (sig) 817 lwpsignal(p, lp, sig); 818 if (lp) 819 LWPRELE(lp); 820 PRELE(p); 821 822 return (0); 823 } 824 825 /* 826 * If we come here, pid is a special broadcast pid. 827 * This doesn't mix with a tid. 828 */ 829 if (tid != -1) 830 return (EINVAL); 831 832 switch (pid) { 833 case -1: /* broadcast signal */ 834 t = (dokillpg(sig, 0, 1)); 835 break; 836 case 0: /* signal own process group */ 837 t = (dokillpg(sig, 0, 0)); 838 break; 839 default: /* negative explicit process group */ 840 t = (dokillpg(sig, -pid, 0)); 841 break; 842 } 843 return t; 844 } 845 846 int 847 sys_kill(struct kill_args *uap) 848 { 849 int error; 850 851 error = kern_kill(uap->signum, uap->pid, -1); 852 return (error); 853 } 854 855 int 856 sys_lwp_kill(struct lwp_kill_args *uap) 857 { 858 int error; 859 pid_t pid = uap->pid; 860 861 /* 862 * A tid is mandatory for lwp_kill(), otherwise 863 * you could simply use kill(). 864 */ 865 if (uap->tid == -1) 866 return (EINVAL); 867 868 /* 869 * To save on a getpid() function call for intra-process 870 * signals, pid == -1 means current process. 871 */ 872 if (pid == -1) 873 pid = curproc->p_pid; 874 875 error = kern_kill(uap->signum, pid, uap->tid); 876 return (error); 877 } 878 879 /* 880 * Send a signal to a process group. 881 */ 882 void 883 gsignal(int pgid, int sig) 884 { 885 struct pgrp *pgrp; 886 887 if (pgid && (pgrp = pgfind(pgid))) 888 pgsignal(pgrp, sig, 0); 889 } 890 891 /* 892 * Send a signal to a process group. If checktty is 1, 893 * limit to members which have a controlling terminal. 894 * 895 * pg_lock interlocks against a fork that might be in progress, to 896 * ensure that the new child process picks up the signal. 897 */ 898 void 899 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 900 { 901 struct proc *p; 902 903 /* 904 * Must interlock all signals against fork 905 */ 906 if (pgrp) { 907 pgref(pgrp); 908 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 909 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 910 if (checkctty == 0 || p->p_flags & P_CONTROLT) 911 ksignal(p, sig); 912 } 913 lockmgr(&pgrp->pg_lock, LK_RELEASE); 914 pgrel(pgrp); 915 } 916 } 917 918 /* 919 * Send a signal caused by a trap to the current lwp. If it will be caught 920 * immediately, deliver it with correct code. Otherwise, post it normally. 921 * 922 * These signals may ONLY be delivered to the specified lwp and may never 923 * be delivered to the process generically. 924 */ 925 void 926 trapsignal(struct lwp *lp, int sig, u_long code) 927 { 928 struct proc *p = lp->lwp_proc; 929 struct sigacts *ps = p->p_sigacts; 930 931 /* 932 * If we are a virtual kernel running an emulated user process 933 * context, switch back to the virtual kernel context before 934 * trying to post the signal. 935 */ 936 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 937 struct trapframe *tf = lp->lwp_md.md_regs; 938 tf->tf_trapno = 0; 939 vkernel_trap(lp, tf); 940 } 941 942 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 943 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 944 lp->lwp_ru.ru_nsignals++; 945 #ifdef KTRACE 946 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 947 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 948 &lp->lwp_sigmask, code); 949 #endif 950 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 951 &lp->lwp_sigmask, code); 952 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 953 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 954 SIGADDSET(lp->lwp_sigmask, sig); 955 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 956 /* 957 * See kern_sigaction() for origin of this code. 958 */ 959 SIGDELSET(p->p_sigcatch, sig); 960 if (sig != SIGCONT && 961 sigprop(sig) & SA_IGNORE) 962 SIGADDSET(p->p_sigignore, sig); 963 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 964 } 965 } else { 966 lp->lwp_code = code; /* XXX for core dump/debugger */ 967 lp->lwp_sig = sig; /* XXX to verify code */ 968 lwpsignal(p, lp, sig); 969 } 970 } 971 972 /* 973 * Find a suitable lwp to deliver the signal to. Returns NULL if all 974 * lwps hold the signal blocked. 975 * 976 * Caller must hold p->p_token. 977 * 978 * Returns a lp or NULL. If non-NULL the lp is held and its token is 979 * acquired. 980 */ 981 static struct lwp * 982 find_lwp_for_signal(struct proc *p, int sig) 983 { 984 struct lwp *lp; 985 struct lwp *run, *sleep, *stop; 986 987 /* 988 * If the running/preempted thread belongs to the proc to which 989 * the signal is being delivered and this thread does not block 990 * the signal, then we can avoid a context switch by delivering 991 * the signal to this thread, because it will return to userland 992 * soon anyways. 993 */ 994 lp = lwkt_preempted_proc(); 995 if (lp != NULL && lp->lwp_proc == p) { 996 LWPHOLD(lp); 997 lwkt_gettoken(&lp->lwp_token); 998 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 999 /* return w/ token held */ 1000 return (lp); 1001 } 1002 lwkt_reltoken(&lp->lwp_token); 1003 LWPRELE(lp); 1004 } 1005 1006 run = sleep = stop = NULL; 1007 FOREACH_LWP_IN_PROC(lp, p) { 1008 /* 1009 * If the signal is being blocked by the lwp, then this 1010 * lwp is not eligible for receiving the signal. 1011 */ 1012 LWPHOLD(lp); 1013 lwkt_gettoken(&lp->lwp_token); 1014 1015 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1016 lwkt_reltoken(&lp->lwp_token); 1017 LWPRELE(lp); 1018 continue; 1019 } 1020 1021 switch (lp->lwp_stat) { 1022 case LSRUN: 1023 if (sleep) { 1024 lwkt_token_swap(); 1025 lwkt_reltoken(&sleep->lwp_token); 1026 LWPRELE(sleep); 1027 sleep = NULL; 1028 run = lp; 1029 } else if (stop) { 1030 lwkt_token_swap(); 1031 lwkt_reltoken(&stop->lwp_token); 1032 LWPRELE(stop); 1033 stop = NULL; 1034 run = lp; 1035 } else { 1036 run = lp; 1037 } 1038 break; 1039 case LSSLEEP: 1040 if (lp->lwp_flags & LWP_SINTR) { 1041 if (sleep) { 1042 lwkt_reltoken(&lp->lwp_token); 1043 LWPRELE(lp); 1044 } else if (stop) { 1045 lwkt_token_swap(); 1046 lwkt_reltoken(&stop->lwp_token); 1047 LWPRELE(stop); 1048 stop = NULL; 1049 sleep = lp; 1050 } else { 1051 sleep = lp; 1052 } 1053 } else { 1054 lwkt_reltoken(&lp->lwp_token); 1055 LWPRELE(lp); 1056 } 1057 break; 1058 case LSSTOP: 1059 if (sleep) { 1060 lwkt_reltoken(&lp->lwp_token); 1061 LWPRELE(lp); 1062 } else if (stop) { 1063 lwkt_reltoken(&lp->lwp_token); 1064 LWPRELE(lp); 1065 } else { 1066 stop = lp; 1067 } 1068 break; 1069 } 1070 if (run) 1071 break; 1072 } 1073 1074 if (run != NULL) 1075 return (run); 1076 else if (sleep != NULL) 1077 return (sleep); 1078 else 1079 return (stop); 1080 } 1081 1082 /* 1083 * Send the signal to the process. If the signal has an action, the action 1084 * is usually performed by the target process rather than the caller; we add 1085 * the signal to the set of pending signals for the process. 1086 * 1087 * Exceptions: 1088 * o When a stop signal is sent to a sleeping process that takes the 1089 * default action, the process is stopped without awakening it. 1090 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1091 * regardless of the signal action (eg, blocked or ignored). 1092 * 1093 * Other ignored signals are discarded immediately. 1094 * 1095 * If the caller wishes to call this function from a hard code section the 1096 * caller must already hold p->p_token (see kern_clock.c). 1097 * 1098 * No requirements. 1099 */ 1100 void 1101 ksignal(struct proc *p, int sig) 1102 { 1103 lwpsignal(p, NULL, sig); 1104 } 1105 1106 /* 1107 * The core for ksignal. lp may be NULL, then a suitable thread 1108 * will be chosen. If not, lp MUST be a member of p. 1109 * 1110 * If the caller wishes to call this function from a hard code section the 1111 * caller must already hold p->p_token. 1112 * 1113 * No requirements. 1114 */ 1115 void 1116 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1117 { 1118 struct proc *q; 1119 sig_t action; 1120 int prop; 1121 1122 if (sig > _SIG_MAXSIG || sig <= 0) { 1123 kprintf("lwpsignal: signal %d\n", sig); 1124 panic("lwpsignal signal number"); 1125 } 1126 1127 KKASSERT(lp == NULL || lp->lwp_proc == p); 1128 1129 /* 1130 * We don't want to race... well, all sorts of things. Get appropriate 1131 * tokens. 1132 * 1133 * Don't try to deliver a generic signal to an exiting process, 1134 * the signal structures could be in flux. We check the LWP later 1135 * on. 1136 */ 1137 PHOLD(p); 1138 if (lp) { 1139 LWPHOLD(lp); 1140 lwkt_gettoken(&lp->lwp_token); 1141 } else { 1142 lwkt_gettoken(&p->p_token); 1143 if (p->p_flags & P_WEXIT) 1144 goto out; 1145 } 1146 1147 prop = sigprop(sig); 1148 1149 /* 1150 * If proc is traced, always give parent a chance; 1151 * if signal event is tracked by procfs, give *that* 1152 * a chance, as well. 1153 */ 1154 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1155 action = SIG_DFL; 1156 } else { 1157 /* 1158 * Do not try to deliver signals to an exiting lwp other 1159 * than SIGKILL. Note that we must still deliver the signal 1160 * if P_WEXIT is set in the process flags. 1161 */ 1162 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { 1163 lwkt_reltoken(&lp->lwp_token); 1164 LWPRELE(lp); 1165 PRELE(p); 1166 return; 1167 } 1168 1169 /* 1170 * If the signal is being ignored, then we forget about 1171 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1172 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1173 */ 1174 if (SIGISMEMBER(p->p_sigignore, sig)) { 1175 /* 1176 * Even if a signal is set SIG_IGN, it may still be 1177 * lurking in a kqueue. 1178 */ 1179 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1180 if (lp) { 1181 lwkt_reltoken(&lp->lwp_token); 1182 LWPRELE(lp); 1183 } else { 1184 lwkt_reltoken(&p->p_token); 1185 } 1186 PRELE(p); 1187 return; 1188 } 1189 if (SIGISMEMBER(p->p_sigcatch, sig)) 1190 action = SIG_CATCH; 1191 else 1192 action = SIG_DFL; 1193 } 1194 1195 /* 1196 * If continuing, clear any pending STOP signals for the whole 1197 * process. 1198 */ 1199 if (prop & SA_CONT) { 1200 lwkt_gettoken(&p->p_token); 1201 SIG_STOPSIGMASK_ATOMIC(p->p_siglist); 1202 lwkt_reltoken(&p->p_token); 1203 } 1204 1205 if (prop & SA_STOP) { 1206 /* 1207 * If sending a tty stop signal to a member of an orphaned 1208 * process group, discard the signal here if the action 1209 * is default; don't stop the process below if sleeping, 1210 * and don't clear any pending SIGCONT. 1211 */ 1212 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && 1213 action == SIG_DFL) { 1214 if (lp) { 1215 lwkt_reltoken(&lp->lwp_token); 1216 LWPRELE(lp); 1217 } else { 1218 lwkt_reltoken(&p->p_token); 1219 } 1220 PRELE(p); 1221 return; 1222 } 1223 lwkt_gettoken(&p->p_token); 1224 SIG_CONTSIGMASK_ATOMIC(p->p_siglist); 1225 p->p_flags &= ~P_CONTINUED; 1226 lwkt_reltoken(&p->p_token); 1227 } 1228 1229 if (p->p_stat == SSTOP) { 1230 /* 1231 * Nobody can handle this signal, add it to the lwp or 1232 * process pending list 1233 */ 1234 lwkt_gettoken(&p->p_token); 1235 if (p->p_stat != SSTOP) { 1236 lwkt_reltoken(&p->p_token); 1237 goto not_stopped; 1238 } 1239 sigsetfrompid(curthread, p, sig); 1240 if (lp) { 1241 spin_lock(&lp->lwp_spin); 1242 SIGADDSET(lp->lwp_siglist, sig); 1243 spin_unlock(&lp->lwp_spin); 1244 } else { 1245 SIGADDSET_ATOMIC(p->p_siglist, sig); 1246 } 1247 1248 /* 1249 * If the process is stopped and is being traced, then no 1250 * further action is necessary. 1251 */ 1252 if (p->p_flags & P_TRACED) { 1253 lwkt_reltoken(&p->p_token); 1254 goto out; 1255 } 1256 1257 /* 1258 * If the process is stopped and receives a KILL signal, 1259 * make the process runnable. 1260 */ 1261 if (sig == SIGKILL) { 1262 proc_unstop(p, SSTOP); 1263 lwkt_reltoken(&p->p_token); 1264 goto active_process; 1265 } 1266 1267 /* 1268 * If the process is stopped and receives a CONT signal, 1269 * then try to make the process runnable again. 1270 */ 1271 if (prop & SA_CONT) { 1272 /* 1273 * If SIGCONT is default (or ignored), we continue the 1274 * process but don't leave the signal in p_siglist, as 1275 * it has no further action. If SIGCONT is held, we 1276 * continue the process and leave the signal in 1277 * p_siglist. If the process catches SIGCONT, let it 1278 * handle the signal itself. 1279 * 1280 * XXX what if the signal is being held blocked? 1281 * 1282 * Token required to interlock kern_wait(). 1283 * Reparenting can also cause a race so we have to 1284 * hold (q). 1285 */ 1286 q = p->p_pptr; 1287 PHOLD(q); 1288 lwkt_gettoken(&q->p_token); 1289 p->p_flags |= P_CONTINUED; 1290 wakeup(q); 1291 if (action == SIG_DFL) 1292 SIGDELSET_ATOMIC(p->p_siglist, sig); 1293 proc_unstop(p, SSTOP); 1294 lwkt_reltoken(&q->p_token); 1295 PRELE(q); 1296 lwkt_reltoken(&p->p_token); 1297 if (action == SIG_CATCH) 1298 goto active_process; 1299 goto out; 1300 } 1301 1302 /* 1303 * If the process is stopped and receives another STOP 1304 * signal, we do not need to stop it again. If we did 1305 * the shell could get confused. 1306 * 1307 * However, if the current/preempted lwp is part of the 1308 * process receiving the signal, we need to keep it, 1309 * so that this lwp can stop in issignal() later, as 1310 * we don't want to wait until it reaches userret! 1311 */ 1312 if (prop & SA_STOP) { 1313 if (lwkt_preempted_proc() == NULL || 1314 lwkt_preempted_proc()->lwp_proc != p) { 1315 SIGDELSET_ATOMIC(p->p_siglist, sig); 1316 } 1317 } 1318 1319 /* 1320 * Otherwise the process is stopped and it received some 1321 * signal, which does not change its stopped state. When 1322 * the process is continued a wakeup(p) will be issued which 1323 * will wakeup any threads sleeping in tstop(). 1324 */ 1325 lwkt_reltoken(&p->p_token); 1326 goto out; 1327 /* NOTREACHED */ 1328 } 1329 not_stopped: 1330 ; 1331 /* else not stopped */ 1332 active_process: 1333 1334 /* 1335 * Never deliver a lwp-specific signal to a random lwp. 1336 */ 1337 if (lp == NULL) { 1338 /* NOTE: returns lp w/ token held */ 1339 lp = find_lwp_for_signal(p, sig); 1340 if (lp) { 1341 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1342 lwkt_reltoken(&lp->lwp_token); 1343 LWPRELE(lp); 1344 lp = NULL; 1345 /* maintain proc token */ 1346 } else { 1347 lwkt_token_swap(); 1348 lwkt_reltoken(&p->p_token); 1349 /* maintain lp token */ 1350 } 1351 } 1352 } 1353 1354 /* 1355 * Deliver to the process generically if (1) the signal is being 1356 * sent to any thread or (2) we could not find a thread to deliver 1357 * it to. 1358 */ 1359 if (lp == NULL) { 1360 sigsetfrompid(curthread, p, sig); 1361 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1362 SIGADDSET_ATOMIC(p->p_siglist, sig); 1363 goto out; 1364 } 1365 1366 /* 1367 * Deliver to a specific LWP whether it masks it or not. It will 1368 * not be dispatched if masked but we must still deliver it. 1369 */ 1370 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1371 (p->p_flags & P_TRACED) == 0) { 1372 lwkt_gettoken(&p->p_token); 1373 p->p_nice = NZERO; 1374 lwkt_reltoken(&p->p_token); 1375 } 1376 1377 /* 1378 * If the process receives a STOP signal which indeed needs to 1379 * stop the process, do so. If the process chose to catch the 1380 * signal, it will be treated like any other signal. 1381 */ 1382 if ((prop & SA_STOP) && action == SIG_DFL) { 1383 /* 1384 * If a child holding parent blocked, stopping 1385 * could cause deadlock. Take no action at this 1386 * time. 1387 */ 1388 lwkt_gettoken(&p->p_token); 1389 if (p->p_flags & P_PPWAIT) { 1390 sigsetfrompid(curthread, p, sig); 1391 SIGADDSET_ATOMIC(p->p_siglist, sig); 1392 lwkt_reltoken(&p->p_token); 1393 goto out; 1394 } 1395 1396 /* 1397 * Do not actually try to manipulate the process, but simply 1398 * stop it. Lwps will stop as soon as they safely can. 1399 * 1400 * Ignore stop if the process is exiting. 1401 */ 1402 if ((p->p_flags & P_WEXIT) == 0) { 1403 p->p_xstat = sig; 1404 proc_stop(p, SSTOP); 1405 } 1406 lwkt_reltoken(&p->p_token); 1407 goto out; 1408 } 1409 1410 /* 1411 * If it is a CONT signal with default action, just ignore it. 1412 */ 1413 if ((prop & SA_CONT) && action == SIG_DFL) 1414 goto out; 1415 1416 /* 1417 * Mark signal pending at this specific thread. 1418 */ 1419 sigsetfrompid(curthread, p, sig); 1420 spin_lock(&lp->lwp_spin); 1421 SIGADDSET(lp->lwp_siglist, sig); 1422 spin_unlock(&lp->lwp_spin); 1423 1424 lwp_signotify(lp); 1425 1426 out: 1427 if (lp) { 1428 lwkt_reltoken(&lp->lwp_token); 1429 LWPRELE(lp); 1430 } else { 1431 lwkt_reltoken(&p->p_token); 1432 } 1433 PRELE(p); 1434 } 1435 1436 /* 1437 * Notify the LWP that a signal has arrived. The LWP does not have to be 1438 * sleeping on the current cpu. 1439 * 1440 * p->p_token and lp->lwp_token must be held on call. 1441 * 1442 * We can only safely schedule the thread on its current cpu and only if 1443 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1444 * the correct cpu we are properly interlocked, otherwise we could be 1445 * racing other thread transition states (or the lwp is on the user scheduler 1446 * runq but not scheduled) and must not do anything. 1447 * 1448 * Since we hold the lwp token we know the lwp cannot be ripped out from 1449 * under us so we can safely hold it to prevent it from being ripped out 1450 * from under us if we are forced to IPI another cpu to make the local 1451 * checks there. 1452 * 1453 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1454 * which we won't in an IPI so any fixups have to be done here, effectively 1455 * replicating part of what setrunnable() does. 1456 */ 1457 static void 1458 lwp_signotify(struct lwp *lp) 1459 { 1460 thread_t dtd; 1461 1462 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1463 dtd = lp->lwp_thread; 1464 1465 crit_enter(); 1466 if (lp == lwkt_preempted_proc()) { 1467 /* 1468 * lwp is on the current cpu AND it is currently running 1469 * (we preempted it). 1470 */ 1471 signotify(); 1472 } else if (lp->lwp_flags & LWP_SINTR) { 1473 /* 1474 * lwp is sitting in tsleep() with PCATCH set 1475 */ 1476 if (dtd->td_gd == mycpu) { 1477 setrunnable(lp); 1478 } else { 1479 /* 1480 * We can only adjust lwp_stat while we hold the 1481 * lwp_token, and we won't in the IPI function. 1482 */ 1483 LWPHOLD(lp); 1484 if (lp->lwp_stat == LSSTOP) 1485 lp->lwp_stat = LSSLEEP; 1486 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1487 } 1488 } else if (dtd->td_flags & TDF_SINTR) { 1489 /* 1490 * lwp is sitting in lwkt_sleep() with PCATCH set. 1491 */ 1492 if (dtd->td_gd == mycpu) { 1493 setrunnable(lp); 1494 } else { 1495 /* 1496 * We can only adjust lwp_stat while we hold the 1497 * lwp_token, and we won't in the IPI function. 1498 */ 1499 LWPHOLD(lp); 1500 if (lp->lwp_stat == LSSTOP) 1501 lp->lwp_stat = LSSLEEP; 1502 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1503 } 1504 } else { 1505 /* 1506 * Otherwise the lwp is either in some uninterruptible state 1507 * or it is on the userland scheduler's runqueue waiting to 1508 * be scheduled to a cpu, or it is running in userland. We 1509 * generally want to send an IPI so a running target gets the 1510 * signal ASAP, otherwise a scheduler-tick worth of latency 1511 * will occur. 1512 * 1513 * Issue an IPI to the remote cpu to knock it into the kernel, 1514 * remote cpu will issue the cpu-local signotify() if the IPI 1515 * preempts the desired thread. 1516 */ 1517 if (dtd->td_gd != mycpu) { 1518 LWPHOLD(lp); 1519 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1520 } 1521 } 1522 crit_exit(); 1523 } 1524 1525 /* 1526 * This function is called via an IPI so we cannot call setrunnable() here 1527 * (because while we hold the lp we don't own its token, and can't get it 1528 * from an IPI). 1529 * 1530 * We are interlocked by virtue of being on the same cpu as the target. If 1531 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1532 * the target thread. 1533 */ 1534 static void 1535 lwp_signotify_remote(void *arg) 1536 { 1537 struct lwp *lp = arg; 1538 thread_t td = lp->lwp_thread; 1539 1540 if (lp == lwkt_preempted_proc()) { 1541 signotify(); 1542 LWPRELE(lp); 1543 } else if (td->td_gd == mycpu) { 1544 if ((lp->lwp_flags & LWP_SINTR) || 1545 (td->td_flags & TDF_SINTR)) { 1546 lwkt_schedule(td); 1547 } 1548 LWPRELE(lp); 1549 } else { 1550 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1551 /* LWPHOLD() is forwarded to the target cpu */ 1552 } 1553 } 1554 1555 /* 1556 * Caller must hold p->p_token 1557 */ 1558 void 1559 proc_stop(struct proc *p, int sig) 1560 { 1561 struct proc *q; 1562 struct lwp *lp; 1563 1564 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1565 1566 /* 1567 * If somebody raced us, be happy with it. SCORE overrides SSTOP. 1568 */ 1569 if (sig == SCORE) { 1570 if (p->p_stat == SCORE || p->p_stat == SZOMB) 1571 return; 1572 } else { 1573 if (p->p_stat == SSTOP || p->p_stat == SCORE || 1574 p->p_stat == SZOMB) { 1575 return; 1576 } 1577 } 1578 p->p_stat = sig; 1579 1580 FOREACH_LWP_IN_PROC(lp, p) { 1581 LWPHOLD(lp); 1582 lwkt_gettoken(&lp->lwp_token); 1583 1584 switch (lp->lwp_stat) { 1585 case LSSTOP: 1586 /* 1587 * Do nothing, we are already counted in 1588 * p_nstopped. 1589 */ 1590 break; 1591 1592 case LSSLEEP: 1593 /* 1594 * We're sleeping, but we will stop before 1595 * returning to userspace, so count us 1596 * as stopped as well. We set LWP_MP_WSTOP 1597 * to signal the lwp that it should not 1598 * increase p_nstopped when reaching tstop(). 1599 * 1600 * LWP_MP_WSTOP is protected by lp->lwp_token. 1601 */ 1602 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1603 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1604 ++p->p_nstopped; 1605 } 1606 break; 1607 1608 case LSRUN: 1609 /* 1610 * We might notify ourself, but that's not 1611 * a problem. 1612 */ 1613 lwp_signotify(lp); 1614 break; 1615 } 1616 lwkt_reltoken(&lp->lwp_token); 1617 LWPRELE(lp); 1618 } 1619 1620 if (p->p_nstopped == p->p_nthreads) { 1621 /* 1622 * Token required to interlock kern_wait(). Reparenting can 1623 * also cause a race so we have to hold (q). 1624 */ 1625 q = p->p_pptr; 1626 PHOLD(q); 1627 lwkt_gettoken(&q->p_token); 1628 p->p_flags &= ~P_WAITED; 1629 wakeup(q); 1630 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1631 ksignal(p->p_pptr, SIGCHLD); 1632 lwkt_reltoken(&q->p_token); 1633 PRELE(q); 1634 } 1635 } 1636 1637 /* 1638 * Caller must hold p_token 1639 */ 1640 void 1641 proc_unstop(struct proc *p, int sig) 1642 { 1643 struct lwp *lp; 1644 1645 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1646 1647 if (p->p_stat != sig) 1648 return; 1649 1650 p->p_stat = SACTIVE; 1651 1652 FOREACH_LWP_IN_PROC(lp, p) { 1653 LWPHOLD(lp); 1654 lwkt_gettoken(&lp->lwp_token); 1655 1656 switch (lp->lwp_stat) { 1657 case LSRUN: 1658 /* 1659 * Uh? Not stopped? Well, I guess that's okay. 1660 */ 1661 if (bootverbose) 1662 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1663 p->p_pid, lp->lwp_tid); 1664 break; 1665 1666 case LSSLEEP: 1667 /* 1668 * Still sleeping. Don't bother waking it up. 1669 * However, if this thread was counted as 1670 * stopped, undo this. 1671 * 1672 * Nevertheless we call setrunnable() so that it 1673 * will wake up in case a signal or timeout arrived 1674 * in the meantime. 1675 * 1676 * LWP_MP_WSTOP is protected by lp->lwp_token. 1677 */ 1678 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1679 atomic_clear_int(&lp->lwp_mpflags, 1680 LWP_MP_WSTOP); 1681 --p->p_nstopped; 1682 } else { 1683 if (bootverbose) 1684 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1685 p->p_pid, lp->lwp_tid); 1686 } 1687 /* FALLTHROUGH */ 1688 1689 case LSSTOP: 1690 /* 1691 * This handles any lwp's waiting in a tsleep with 1692 * SIGCATCH. 1693 */ 1694 lwp_signotify(lp); 1695 break; 1696 1697 } 1698 lwkt_reltoken(&lp->lwp_token); 1699 LWPRELE(lp); 1700 } 1701 1702 /* 1703 * This handles any lwp's waiting in tstop(). We have interlocked 1704 * the setting of p_stat by acquiring and releasing each lpw's 1705 * token. 1706 */ 1707 wakeup(p); 1708 } 1709 1710 /* 1711 * Wait for all threads except the current thread to stop. 1712 */ 1713 static void 1714 proc_stopwait(struct proc *p) 1715 { 1716 while ((p->p_stat == SSTOP || p->p_stat == SCORE) && 1717 p->p_nstopped < p->p_nthreads - 1) { 1718 tsleep_interlock(&p->p_nstopped, 0); 1719 if (p->p_nstopped < p->p_nthreads - 1) { 1720 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); 1721 } 1722 } 1723 } 1724 1725 /* 1726 * No requirements. 1727 */ 1728 static int 1729 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1730 { 1731 sigset_t savedmask, set; 1732 struct proc *p = curproc; 1733 struct lwp *lp = curthread->td_lwp; 1734 int error, sig, hz, timevalid = 0; 1735 struct timespec rts, ets, ts; 1736 struct timeval tv; 1737 1738 error = 0; 1739 sig = 0; 1740 ets.tv_sec = 0; /* silence compiler warning */ 1741 ets.tv_nsec = 0; /* silence compiler warning */ 1742 SIG_CANTMASK(waitset); 1743 savedmask = lp->lwp_sigmask; 1744 1745 if (timeout) { 1746 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1747 timeout->tv_nsec < 1000000000) { 1748 timevalid = 1; 1749 getnanouptime(&rts); 1750 timespecadd(&rts, timeout, &ets); 1751 } 1752 } 1753 1754 for (;;) { 1755 set = lwp_sigpend(lp); 1756 SIGSETAND(set, waitset); 1757 if ((sig = sig_ffs(&set)) != 0) { 1758 SIGFILLSET(lp->lwp_sigmask); 1759 SIGDELSET(lp->lwp_sigmask, sig); 1760 SIG_CANTMASK(lp->lwp_sigmask); 1761 sig = issignal(lp, 1, 0); 1762 /* 1763 * It may be a STOP signal, in the case, issignal 1764 * returns 0, because we may stop there, and new 1765 * signal can come in, we should restart if we got 1766 * nothing. 1767 */ 1768 if (sig == 0) 1769 continue; 1770 else 1771 break; 1772 } 1773 1774 /* 1775 * Previous checking got nothing, and we retried but still 1776 * got nothing, we should return the error status. 1777 */ 1778 if (error) 1779 break; 1780 1781 /* 1782 * POSIX says this must be checked after looking for pending 1783 * signals. 1784 */ 1785 if (timeout) { 1786 if (timevalid == 0) { 1787 error = EINVAL; 1788 break; 1789 } 1790 getnanouptime(&rts); 1791 if (timespeccmp(&rts, &ets, >=)) { 1792 error = EAGAIN; 1793 break; 1794 } 1795 timespecsub(&ets, &rts, &ts); 1796 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1797 hz = tvtohz_high(&tv); 1798 } else { 1799 hz = 0; 1800 } 1801 1802 lp->lwp_sigmask = savedmask; 1803 SIGSETNAND(lp->lwp_sigmask, waitset); 1804 /* 1805 * We won't ever be woken up. Instead, our sleep will 1806 * be broken in lwpsignal(). 1807 */ 1808 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1809 if (timeout) { 1810 if (error == ERESTART) { 1811 /* can not restart a timeout wait. */ 1812 error = EINTR; 1813 } else if (error == EAGAIN) { 1814 /* will calculate timeout by ourself. */ 1815 error = 0; 1816 } 1817 } 1818 /* Retry ... */ 1819 } 1820 1821 lp->lwp_sigmask = savedmask; 1822 if (sig) { 1823 error = 0; 1824 bzero(info, sizeof(*info)); 1825 info->si_signo = sig; 1826 spin_lock(&lp->lwp_spin); 1827 lwp_delsig(lp, sig, 1); /* take the signal! */ 1828 spin_unlock(&lp->lwp_spin); 1829 1830 if (sig == SIGKILL) { 1831 sigexit(lp, sig); 1832 /* NOT REACHED */ 1833 } 1834 } 1835 1836 return (error); 1837 } 1838 1839 /* 1840 * MPALMOSTSAFE 1841 */ 1842 int 1843 sys_sigtimedwait(struct sigtimedwait_args *uap) 1844 { 1845 struct timespec ts; 1846 struct timespec *timeout; 1847 sigset_t set; 1848 siginfo_t info; 1849 int error; 1850 1851 if (uap->timeout) { 1852 error = copyin(uap->timeout, &ts, sizeof(ts)); 1853 if (error) 1854 return (error); 1855 timeout = &ts; 1856 } else { 1857 timeout = NULL; 1858 } 1859 error = copyin(uap->set, &set, sizeof(set)); 1860 if (error) 1861 return (error); 1862 error = kern_sigtimedwait(set, &info, timeout); 1863 if (error) 1864 return (error); 1865 if (uap->info) 1866 error = copyout(&info, uap->info, sizeof(info)); 1867 /* Repost if we got an error. */ 1868 /* 1869 * XXX lwp 1870 * 1871 * This could transform a thread-specific signal to another 1872 * thread / process pending signal. 1873 */ 1874 if (error) { 1875 ksignal(curproc, info.si_signo); 1876 } else { 1877 uap->sysmsg_result = info.si_signo; 1878 } 1879 return (error); 1880 } 1881 1882 /* 1883 * MPALMOSTSAFE 1884 */ 1885 int 1886 sys_sigwaitinfo(struct sigwaitinfo_args *uap) 1887 { 1888 siginfo_t info; 1889 sigset_t set; 1890 int error; 1891 1892 error = copyin(uap->set, &set, sizeof(set)); 1893 if (error) 1894 return (error); 1895 error = kern_sigtimedwait(set, &info, NULL); 1896 if (error) 1897 return (error); 1898 if (uap->info) 1899 error = copyout(&info, uap->info, sizeof(info)); 1900 /* Repost if we got an error. */ 1901 /* 1902 * XXX lwp 1903 * 1904 * This could transform a thread-specific signal to another 1905 * thread / process pending signal. 1906 */ 1907 if (error) { 1908 ksignal(curproc, info.si_signo); 1909 } else { 1910 uap->sysmsg_result = info.si_signo; 1911 } 1912 return (error); 1913 } 1914 1915 /* 1916 * If the current process has received a signal that would interrupt a 1917 * system call, return EINTR or ERESTART as appropriate. 1918 */ 1919 int 1920 iscaught(struct lwp *lp) 1921 { 1922 struct proc *p = lp->lwp_proc; 1923 int sig; 1924 1925 if (p) { 1926 if ((sig = CURSIG(lp)) != 0) { 1927 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1928 return (EINTR); 1929 return (ERESTART); 1930 } 1931 } 1932 return(EWOULDBLOCK); 1933 } 1934 1935 /* 1936 * If the current lwp/proc has received a signal (should be caught or cause 1937 * termination, should interrupt current syscall), return the signal number. 1938 * Stop signals with default action are processed immediately, then cleared; 1939 * they aren't returned. This is checked after each entry to the system for 1940 * a syscall or trap (though this can usually be done without calling issignal 1941 * by checking the pending signal masks in the CURSIG macro). 1942 * 1943 * This routine is called via CURSIG/__cursig. We will acquire and release 1944 * p->p_token but if the caller needs to interlock the test the caller must 1945 * also hold p->p_token. 1946 * 1947 * while (sig = CURSIG(curproc)) 1948 * postsig(sig); 1949 */ 1950 int 1951 issignal(struct lwp *lp, int maytrace, int *ptokp) 1952 { 1953 struct proc *p = lp->lwp_proc; 1954 sigset_t mask; 1955 int sig, prop; 1956 int haveptok; 1957 1958 for (;;) { 1959 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1960 1961 haveptok = 0; 1962 1963 /* 1964 * NOTE: Do not tstop here. Issue the proc_stop() 1965 * so other parties see that we know we need 1966 * to stop, but don't block here. Locks might 1967 * be held. 1968 * 1969 * XXX If this process is supposed to stop, stop this thread. 1970 * removed. 1971 */ 1972 #if 0 1973 if (STOPLWP(p, lp)) { 1974 lwkt_gettoken(&p->p_token); 1975 tstop(); 1976 lwkt_reltoken(&p->p_token); 1977 } 1978 #endif 1979 1980 /* 1981 * Quick check without token 1982 */ 1983 mask = lwp_sigpend(lp); 1984 SIGSETNAND(mask, lp->lwp_sigmask); 1985 if (p->p_flags & P_PPWAIT) 1986 SIG_STOPSIGMASK(mask); 1987 if (SIGISEMPTY(mask)) /* no signal to send */ 1988 return (0); 1989 1990 /* 1991 * If the signal is a member of the process signal set 1992 * we need p_token (even if it is also a member of the 1993 * lwp signal set). 1994 */ 1995 sig = sig_ffs(&mask); 1996 if (SIGISMEMBER(p->p_siglist, sig)) { 1997 /* 1998 * Recheck with token 1999 */ 2000 haveptok = 1; 2001 lwkt_gettoken(&p->p_token); 2002 2003 mask = lwp_sigpend(lp); 2004 SIGSETNAND(mask, lp->lwp_sigmask); 2005 if (p->p_flags & P_PPWAIT) 2006 SIG_STOPSIGMASK(mask); 2007 if (SIGISEMPTY(mask)) { /* no signal to send */ 2008 /* haveptok is TRUE */ 2009 lwkt_reltoken(&p->p_token); 2010 return (0); 2011 } 2012 sig = sig_ffs(&mask); 2013 } 2014 2015 STOPEVENT(p, S_SIG, sig); 2016 2017 /* 2018 * We should see pending but ignored signals 2019 * only if P_TRACED was on when they were posted. 2020 */ 2021 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 2022 spin_lock(&lp->lwp_spin); 2023 lwp_delsig(lp, sig, haveptok); 2024 spin_unlock(&lp->lwp_spin); 2025 if (haveptok) 2026 lwkt_reltoken(&p->p_token); 2027 continue; 2028 } 2029 if (maytrace && 2030 (p->p_flags & P_TRACED) && 2031 (p->p_flags & P_PPWAIT) == 0) { 2032 /* 2033 * If traced, always stop, and stay stopped until 2034 * released by the parent. 2035 * 2036 * NOTE: SSTOP may get cleared during the loop, but 2037 * we do not re-notify the parent if we have 2038 * to loop several times waiting for the parent 2039 * to let us continue. XXX not sure if this is 2040 * still true 2041 * 2042 * NOTE: Do not tstop here. Issue the proc_stop() 2043 * so other parties see that we know we need 2044 * to stop, but don't block here. Locks might 2045 * be held. 2046 */ 2047 if (haveptok == 0) { 2048 lwkt_gettoken(&p->p_token); 2049 haveptok = 1; 2050 } 2051 p->p_xstat = sig; 2052 proc_stop(p, SSTOP); 2053 2054 /* 2055 * Normally we don't stop until we return to userland, but 2056 * make an exception when tracing and 'maytrace' is asserted. 2057 */ 2058 if (p->p_flags & P_TRACED) 2059 tstop(); 2060 2061 /* 2062 * If parent wants us to take the signal, 2063 * then it will leave it in p->p_xstat; 2064 * otherwise we just look for signals again. 2065 */ 2066 spin_lock(&lp->lwp_spin); 2067 lwp_delsig(lp, sig, 1); /* clear old signal */ 2068 spin_unlock(&lp->lwp_spin); 2069 sig = p->p_xstat; 2070 if (sig == 0) { 2071 /* haveptok is TRUE */ 2072 lwkt_reltoken(&p->p_token); 2073 continue; 2074 } 2075 2076 /* 2077 * Put the new signal into p_siglist. If the 2078 * signal is being masked, look for other signals. 2079 * 2080 * XXX lwp might need a call to ksignal() 2081 */ 2082 SIGADDSET_ATOMIC(p->p_siglist, sig); 2083 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 2084 /* haveptok is TRUE */ 2085 lwkt_reltoken(&p->p_token); 2086 continue; 2087 } 2088 2089 /* 2090 * If the traced bit got turned off, go back up 2091 * to the top to rescan signals. This ensures 2092 * that p_sig* and ps_sigact are consistent. 2093 */ 2094 if ((p->p_flags & P_TRACED) == 0) { 2095 /* haveptok is TRUE */ 2096 lwkt_reltoken(&p->p_token); 2097 continue; 2098 } 2099 } 2100 2101 /* 2102 * p_token may be held here 2103 */ 2104 prop = sigprop(sig); 2105 2106 /* 2107 * Decide whether the signal should be returned. 2108 * Return the signal's number, or fall through 2109 * to clear it from the pending mask. 2110 */ 2111 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2112 case (intptr_t)SIG_DFL: 2113 /* 2114 * Don't take default actions on system processes. 2115 */ 2116 if (p->p_pid <= 1) { 2117 #ifdef DIAGNOSTIC 2118 /* 2119 * Are you sure you want to ignore SIGSEGV 2120 * in init? XXX 2121 */ 2122 kprintf("Process (pid %lu) got signal %d\n", 2123 (u_long)p->p_pid, sig); 2124 #endif 2125 break; /* == ignore */ 2126 } 2127 2128 /* 2129 * Handle the in-kernel checkpoint action 2130 */ 2131 if (prop & SA_CKPT) { 2132 if (haveptok == 0) { 2133 lwkt_gettoken(&p->p_token); 2134 haveptok = 1; 2135 } 2136 checkpoint_signal_handler(lp); 2137 break; 2138 } 2139 2140 /* 2141 * If there is a pending stop signal to process 2142 * with default action, stop here, 2143 * then clear the signal. However, 2144 * if process is member of an orphaned 2145 * process group, ignore tty stop signals. 2146 */ 2147 if (prop & SA_STOP) { 2148 if (haveptok == 0) { 2149 lwkt_gettoken(&p->p_token); 2150 haveptok = 1; 2151 } 2152 if (p->p_flags & P_TRACED || 2153 (p->p_pgrp->pg_jobc == 0 && 2154 prop & SA_TTYSTOP)) 2155 break; /* == ignore */ 2156 if ((p->p_flags & P_WEXIT) == 0) { 2157 /* 2158 * NOTE: We do not block here. Issue 2159 * stopthe stop so other parties 2160 * see that we know we need to 2161 * stop. Locks might be held. 2162 */ 2163 p->p_xstat = sig; 2164 proc_stop(p, SSTOP); 2165 2166 #if 0 2167 tstop(); 2168 #endif 2169 } 2170 break; 2171 } else if (prop & SA_IGNORE) { 2172 /* 2173 * Except for SIGCONT, shouldn't get here. 2174 * Default action is to ignore; drop it. 2175 */ 2176 break; /* == ignore */ 2177 } else { 2178 if (ptokp) 2179 *ptokp = haveptok; 2180 else if (haveptok) 2181 lwkt_reltoken(&p->p_token); 2182 return (sig); 2183 } 2184 2185 /*NOTREACHED*/ 2186 2187 case (intptr_t)SIG_IGN: 2188 /* 2189 * Masking above should prevent us ever trying 2190 * to take action on an ignored signal other 2191 * than SIGCONT, unless process is traced. 2192 */ 2193 if ((prop & SA_CONT) == 0 && 2194 (p->p_flags & P_TRACED) == 0) 2195 kprintf("issignal\n"); 2196 break; /* == ignore */ 2197 2198 default: 2199 /* 2200 * This signal has an action, let 2201 * postsig() process it. 2202 */ 2203 if (ptokp) 2204 *ptokp = haveptok; 2205 else if (haveptok) 2206 lwkt_reltoken(&p->p_token); 2207 return (sig); 2208 } 2209 spin_lock(&lp->lwp_spin); 2210 lwp_delsig(lp, sig, haveptok); /* take the signal! */ 2211 spin_unlock(&lp->lwp_spin); 2212 2213 if (haveptok) 2214 lwkt_reltoken(&p->p_token); 2215 } 2216 /* NOTREACHED */ 2217 } 2218 2219 /* 2220 * Take the action for the specified signal from the current set of 2221 * pending signals. 2222 * 2223 * haveptok indicates whether the caller is holding p->p_token. If the 2224 * caller is, we are responsible for releasing it. 2225 * 2226 * This routine can only be called from the top-level trap from usermode. 2227 * It is expecting to be able to modify the top-level stack frame. 2228 */ 2229 void 2230 postsig(int sig, int haveptok) 2231 { 2232 struct lwp *lp = curthread->td_lwp; 2233 struct proc *p = lp->lwp_proc; 2234 struct sigacts *ps = p->p_sigacts; 2235 sig_t action; 2236 sigset_t returnmask; 2237 int code; 2238 2239 KASSERT(sig != 0, ("postsig")); 2240 2241 /* 2242 * If we are a virtual kernel running an emulated user process 2243 * context, switch back to the virtual kernel context before 2244 * trying to post the signal. 2245 */ 2246 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2247 struct trapframe *tf = lp->lwp_md.md_regs; 2248 tf->tf_trapno = 0; 2249 vkernel_trap(lp, tf); 2250 } 2251 2252 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2253 2254 spin_lock(&lp->lwp_spin); 2255 lwp_delsig(lp, sig, haveptok); 2256 spin_unlock(&lp->lwp_spin); 2257 action = ps->ps_sigact[_SIG_IDX(sig)]; 2258 #ifdef KTRACE 2259 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2260 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2261 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2262 #endif 2263 /* 2264 * We don't need p_token after this point. 2265 */ 2266 if (haveptok) 2267 lwkt_reltoken(&p->p_token); 2268 2269 STOPEVENT(p, S_SIG, sig); 2270 2271 if (action == SIG_DFL) { 2272 /* 2273 * Default action, where the default is to kill 2274 * the process. (Other cases were ignored above.) 2275 */ 2276 sigexit(lp, sig); 2277 /* NOTREACHED */ 2278 } else { 2279 /* 2280 * If we get here, the signal must be caught. 2281 */ 2282 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2283 ("postsig action")); 2284 2285 /* 2286 * Reset the signal handler if asked to 2287 */ 2288 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2289 /* 2290 * See kern_sigaction() for origin of this code. 2291 */ 2292 SIGDELSET(p->p_sigcatch, sig); 2293 if (sig != SIGCONT && 2294 sigprop(sig) & SA_IGNORE) 2295 SIGADDSET(p->p_sigignore, sig); 2296 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2297 } 2298 2299 /* 2300 * Set the signal mask and calculate the mask to restore 2301 * when the signal function returns. 2302 * 2303 * Special case: user has done a sigsuspend. Here the 2304 * current mask is not of interest, but rather the 2305 * mask from before the sigsuspend is what we want 2306 * restored after the signal processing is completed. 2307 */ 2308 if (lp->lwp_flags & LWP_OLDMASK) { 2309 returnmask = lp->lwp_oldsigmask; 2310 lp->lwp_flags &= ~LWP_OLDMASK; 2311 } else { 2312 returnmask = lp->lwp_sigmask; 2313 } 2314 2315 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2316 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2317 SIGADDSET(lp->lwp_sigmask, sig); 2318 2319 lp->lwp_ru.ru_nsignals++; 2320 if (lp->lwp_sig != sig) { 2321 code = 0; 2322 } else { 2323 code = lp->lwp_code; 2324 lp->lwp_code = 0; 2325 lp->lwp_sig = 0; 2326 } 2327 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2328 } 2329 } 2330 2331 /* 2332 * Kill the current process for stated reason. 2333 */ 2334 void 2335 killproc(struct proc *p, char *why) 2336 { 2337 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2338 p->p_pid, p->p_comm, 2339 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2340 ksignal(p, SIGKILL); 2341 } 2342 2343 /* 2344 * Force the current process to exit with the specified signal, dumping core 2345 * if appropriate. We bypass the normal tests for masked and caught signals, 2346 * allowing unrecoverable failures to terminate the process without changing 2347 * signal state. Mark the accounting record with the signal termination. 2348 * If dumping core, save the signal number for the debugger. Calls exit and 2349 * does not return. 2350 * 2351 * This routine does not return. 2352 */ 2353 void 2354 sigexit(struct lwp *lp, int sig) 2355 { 2356 struct proc *p = lp->lwp_proc; 2357 2358 lwkt_gettoken(&p->p_token); 2359 p->p_acflag |= AXSIG; 2360 if (sigprop(sig) & SA_CORE) { 2361 lp->lwp_sig = sig; 2362 2363 /* 2364 * All threads must be stopped before we can safely coredump. 2365 * Stop threads using SCORE, which cannot be overridden. 2366 */ 2367 if (p->p_stat != SCORE) { 2368 proc_stop(p, SCORE); 2369 proc_stopwait(p); 2370 2371 if (coredump(lp, sig) == 0) 2372 sig |= WCOREFLAG; 2373 p->p_stat = SSTOP; 2374 } 2375 2376 /* 2377 * Log signals which would cause core dumps 2378 * (Log as LOG_INFO to appease those who don't want 2379 * these messages.) 2380 * XXX : Todo, as well as euid, write out ruid too 2381 */ 2382 if (kern_logsigexit) { 2383 log(LOG_INFO, 2384 "pid %d (%s), uid %d: exited on signal %d%s\n", 2385 p->p_pid, p->p_comm, 2386 p->p_ucred ? p->p_ucred->cr_uid : -1, 2387 sig &~ WCOREFLAG, 2388 sig & WCOREFLAG ? " (core dumped)" : ""); 2389 if (kern_logsigexit > 1) 2390 kprintf("DEBUG - waiting on kern.logsigexit\n"); 2391 while (kern_logsigexit > 1) { 2392 tsleep(&kern_logsigexit, 0, "DEBUG", hz); 2393 } 2394 } 2395 } 2396 lwkt_reltoken(&p->p_token); 2397 exit1(W_EXITCODE(0, sig)); 2398 /* NOTREACHED */ 2399 } 2400 2401 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2402 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2403 sizeof(corefilename), "process corefile name format string"); 2404 2405 /* 2406 * expand_name(name, uid, pid) 2407 * Expand the name described in corefilename, using name, uid, and pid. 2408 * corefilename is a kprintf-like string, with three format specifiers: 2409 * %N name of process ("name") 2410 * %P process id (pid) 2411 * %U user id (uid) 2412 * For example, "%N.core" is the default; they can be disabled completely 2413 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2414 * This is controlled by the sysctl variable kern.corefile (see above). 2415 */ 2416 2417 static char * 2418 expand_name(const char *name, uid_t uid, pid_t pid) 2419 { 2420 char *temp; 2421 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2422 int i, n; 2423 char *format = corefilename; 2424 size_t namelen; 2425 2426 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2427 if (temp == NULL) 2428 return NULL; 2429 namelen = strlen(name); 2430 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2431 int l; 2432 switch (format[i]) { 2433 case '%': /* Format character */ 2434 i++; 2435 switch (format[i]) { 2436 case '%': 2437 temp[n++] = '%'; 2438 break; 2439 case 'N': /* process name */ 2440 if ((n + namelen) > MAXPATHLEN) { 2441 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2442 pid, name, uid, temp, name); 2443 kfree(temp, M_TEMP); 2444 return NULL; 2445 } 2446 memcpy(temp+n, name, namelen); 2447 n += namelen; 2448 break; 2449 case 'P': /* process id */ 2450 l = ksprintf(buf, "%u", pid); 2451 if ((n + l) > MAXPATHLEN) { 2452 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2453 pid, name, uid, temp, name); 2454 kfree(temp, M_TEMP); 2455 return NULL; 2456 } 2457 memcpy(temp+n, buf, l); 2458 n += l; 2459 break; 2460 case 'U': /* user id */ 2461 l = ksprintf(buf, "%u", uid); 2462 if ((n + l) > MAXPATHLEN) { 2463 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2464 pid, name, uid, temp, name); 2465 kfree(temp, M_TEMP); 2466 return NULL; 2467 } 2468 memcpy(temp+n, buf, l); 2469 n += l; 2470 break; 2471 default: 2472 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2473 } 2474 break; 2475 default: 2476 temp[n++] = format[i]; 2477 } 2478 } 2479 temp[n] = '\0'; 2480 return temp; 2481 } 2482 2483 /* 2484 * Dump a process' core. The main routine does some 2485 * policy checking, and creates the name of the coredump; 2486 * then it passes on a vnode and a size limit to the process-specific 2487 * coredump routine if there is one; if there _is not_ one, it returns 2488 * ENOSYS; otherwise it returns the error from the process-specific routine. 2489 * 2490 * The parameter `lp' is the lwp which triggered the coredump. 2491 */ 2492 2493 static int 2494 coredump(struct lwp *lp, int sig) 2495 { 2496 struct proc *p = lp->lwp_proc; 2497 struct vnode *vp; 2498 struct ucred *cred = p->p_ucred; 2499 struct flock lf; 2500 struct nlookupdata nd; 2501 struct vattr vattr; 2502 int error, error1; 2503 char *name; /* name of corefile */ 2504 off_t limit; 2505 2506 STOPEVENT(p, S_CORE, 0); 2507 2508 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2509 return (EFAULT); 2510 2511 /* 2512 * Note that the bulk of limit checking is done after 2513 * the corefile is created. The exception is if the limit 2514 * for corefiles is 0, in which case we don't bother 2515 * creating the corefile at all. This layout means that 2516 * a corefile is truncated instead of not being created, 2517 * if it is larger than the limit. 2518 */ 2519 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2520 if (limit == 0) 2521 return EFBIG; 2522 2523 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2524 if (name == NULL) 2525 return (EINVAL); 2526 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2527 if (error == 0) 2528 error = vn_open(&nd, NULL, 2529 O_CREAT | FWRITE | O_NOFOLLOW, 2530 S_IRUSR | S_IWUSR); 2531 kfree(name, M_TEMP); 2532 if (error) { 2533 nlookup_done(&nd); 2534 return (error); 2535 } 2536 vp = nd.nl_open_vp; 2537 nd.nl_open_vp = NULL; 2538 nlookup_done(&nd); 2539 2540 vn_unlock(vp); 2541 lf.l_whence = SEEK_SET; 2542 lf.l_start = 0; 2543 lf.l_len = 0; 2544 lf.l_type = F_WRLCK; 2545 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2546 if (error) 2547 goto out2; 2548 2549 /* Don't dump to non-regular files or files with links. */ 2550 if (vp->v_type != VREG || 2551 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2552 error = EFAULT; 2553 goto out1; 2554 } 2555 2556 /* Don't dump to files current user does not own */ 2557 if (vattr.va_uid != p->p_ucred->cr_uid) { 2558 error = EFAULT; 2559 goto out1; 2560 } 2561 2562 VATTR_NULL(&vattr); 2563 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2564 vattr.va_size = 0; 2565 VOP_SETATTR(vp, &vattr, cred); 2566 p->p_acflag |= ACORE; 2567 vn_unlock(vp); 2568 2569 error = p->p_sysent->sv_coredump ? 2570 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2571 2572 out1: 2573 lf.l_type = F_UNLCK; 2574 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2575 out2: 2576 error1 = vn_close(vp, FWRITE, NULL); 2577 if (error == 0) 2578 error = error1; 2579 return (error); 2580 } 2581 2582 /* 2583 * Nonexistent system call-- signal process (may want to handle it). 2584 * Flag error in case process won't see signal immediately (blocked or ignored). 2585 * 2586 * MPALMOSTSAFE 2587 */ 2588 /* ARGSUSED */ 2589 int 2590 sys_nosys(struct nosys_args *args) 2591 { 2592 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2593 return (EINVAL); 2594 } 2595 2596 /* 2597 * Send a SIGIO or SIGURG signal to a process or process group using 2598 * stored credentials rather than those of the current process. 2599 */ 2600 void 2601 pgsigio(struct sigio *sigio, int sig, int checkctty) 2602 { 2603 if (sigio == NULL) 2604 return; 2605 2606 if (sigio->sio_pgid > 0) { 2607 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2608 sigio->sio_proc)) 2609 ksignal(sigio->sio_proc, sig); 2610 } else if (sigio->sio_pgid < 0) { 2611 struct proc *p; 2612 struct pgrp *pg = sigio->sio_pgrp; 2613 2614 /* 2615 * Must interlock all signals against fork 2616 */ 2617 pgref(pg); 2618 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2619 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2620 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2621 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2622 ksignal(p, sig); 2623 } 2624 lockmgr(&pg->pg_lock, LK_RELEASE); 2625 pgrel(pg); 2626 } 2627 } 2628 2629 static int 2630 filt_sigattach(struct knote *kn) 2631 { 2632 struct proc *p = curproc; 2633 2634 kn->kn_ptr.p_proc = p; 2635 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2636 2637 /* XXX lock the proc here while adding to the list? */ 2638 knote_insert(&p->p_klist, kn); 2639 2640 return (0); 2641 } 2642 2643 static void 2644 filt_sigdetach(struct knote *kn) 2645 { 2646 struct proc *p = kn->kn_ptr.p_proc; 2647 2648 knote_remove(&p->p_klist, kn); 2649 } 2650 2651 /* 2652 * signal knotes are shared with proc knotes, so we apply a mask to 2653 * the hint in order to differentiate them from process hints. This 2654 * could be avoided by using a signal-specific knote list, but probably 2655 * isn't worth the trouble. 2656 */ 2657 static int 2658 filt_signal(struct knote *kn, long hint) 2659 { 2660 if (hint & NOTE_SIGNAL) { 2661 hint &= ~NOTE_SIGNAL; 2662 2663 if (kn->kn_id == hint) 2664 kn->kn_data++; 2665 } 2666 return (kn->kn_data != 0); 2667 } 2668