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/sysmsg.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 __read_mostly sigset_t sigcantmask_mask; 208 209 static __inline int 210 sigprop(int sig) 211 { 212 213 if (sig > 0 && sig < NSIG) 214 return (sigproptbl[_SIG_IDX(sig)]); 215 216 return (0); 217 } 218 219 static __inline int 220 sig_ffs(sigset_t *set) 221 { 222 int i; 223 224 for (i = 0; i < _SIG_WORDS; i++) 225 if (set->__bits[i]) 226 return (ffs(set->__bits[i]) + (i * 32)); 227 return (0); 228 } 229 230 /* 231 * Allows us to populate siginfo->si_pid and si_uid in the target process 232 * (p) from the originating thread (td). This function must work properly 233 * even if a kernel thread is sending the signal. 234 * 235 * NOTE: Signals are not queued, so if multiple signals are received the 236 * signal handler will only see the most recent pid and uid for any 237 * given signal number. 238 */ 239 static __inline void 240 sigsetfrompid(thread_t td, struct proc *p, int sig) 241 { 242 struct sigacts *sap; 243 244 if ((sap = p->p_sigacts) == NULL) 245 return; 246 if (td->td_proc) { 247 sap->ps_frominfo[sig].pid = td->td_proc->p_pid; 248 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid; 249 } else { 250 sap->ps_frominfo[sig].pid = 0; 251 sap->ps_frominfo[sig].uid = 0; 252 } 253 } 254 255 /* 256 * No requirements. 257 */ 258 int 259 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 260 { 261 struct thread *td = curthread; 262 struct proc *p = td->td_proc; 263 struct lwp *lp; 264 struct sigacts *ps = p->p_sigacts; 265 266 if (sig <= 0 || sig >= _SIG_MAXSIG) 267 return (EINVAL); 268 269 lwkt_gettoken(&p->p_token); 270 271 if (oact) { 272 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 273 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 274 oact->sa_flags = 0; 275 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 276 oact->sa_flags |= SA_ONSTACK; 277 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 278 oact->sa_flags |= SA_RESTART; 279 if (SIGISMEMBER(ps->ps_sigreset, sig)) 280 oact->sa_flags |= SA_RESETHAND; 281 if (SIGISMEMBER(ps->ps_signodefer, sig)) 282 oact->sa_flags |= SA_NODEFER; 283 if (SIGISMEMBER(ps->ps_siginfo, sig)) 284 oact->sa_flags |= SA_SIGINFO; 285 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 286 oact->sa_flags |= SA_NOCLDSTOP; 287 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 288 oact->sa_flags |= SA_NOCLDWAIT; 289 } 290 if (act) { 291 /* 292 * Check for invalid requests. KILL and STOP cannot be 293 * caught. 294 */ 295 if (sig == SIGKILL || sig == SIGSTOP) { 296 if (act->sa_handler != SIG_DFL) { 297 lwkt_reltoken(&p->p_token); 298 return (EINVAL); 299 } 300 } 301 302 /* 303 * Change setting atomically. 304 */ 305 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 306 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 307 if (act->sa_flags & SA_SIGINFO) { 308 ps->ps_sigact[_SIG_IDX(sig)] = 309 (__sighandler_t *)act->sa_sigaction; 310 SIGADDSET(ps->ps_siginfo, sig); 311 } else { 312 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 313 SIGDELSET(ps->ps_siginfo, sig); 314 } 315 if (!(act->sa_flags & SA_RESTART)) 316 SIGADDSET(ps->ps_sigintr, sig); 317 else 318 SIGDELSET(ps->ps_sigintr, sig); 319 if (act->sa_flags & SA_ONSTACK) 320 SIGADDSET(ps->ps_sigonstack, sig); 321 else 322 SIGDELSET(ps->ps_sigonstack, sig); 323 if (act->sa_flags & SA_RESETHAND) 324 SIGADDSET(ps->ps_sigreset, sig); 325 else 326 SIGDELSET(ps->ps_sigreset, sig); 327 if (act->sa_flags & SA_NODEFER) 328 SIGADDSET(ps->ps_signodefer, sig); 329 else 330 SIGDELSET(ps->ps_signodefer, sig); 331 if (sig == SIGCHLD) { 332 if (act->sa_flags & SA_NOCLDSTOP) 333 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 334 else 335 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 336 if (act->sa_flags & SA_NOCLDWAIT) { 337 /* 338 * Paranoia: since SA_NOCLDWAIT is implemented 339 * by reparenting the dying child to PID 1 (and 340 * trust it to reap the zombie), PID 1 itself 341 * is forbidden to set SA_NOCLDWAIT. 342 */ 343 if (p->p_pid == 1) 344 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 345 else 346 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 347 } else { 348 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 349 } 350 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 351 ps->ps_flag |= PS_CLDSIGIGN; 352 else 353 ps->ps_flag &= ~PS_CLDSIGIGN; 354 } 355 /* 356 * Set bit in p_sigignore for signals that are set to SIG_IGN, 357 * and for signals set to SIG_DFL where the default is to 358 * ignore. However, don't put SIGCONT in p_sigignore, as we 359 * have to restart the process. 360 * 361 * Also remove the signal from the process and lwp signal 362 * list. 363 */ 364 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 365 (sigprop(sig) & SA_IGNORE && 366 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 367 SIGDELSET_ATOMIC(p->p_siglist, sig); 368 FOREACH_LWP_IN_PROC(lp, p) { 369 spin_lock(&lp->lwp_spin); 370 SIGDELSET(lp->lwp_siglist, sig); 371 spin_unlock(&lp->lwp_spin); 372 } 373 if (sig != SIGCONT) { 374 /* easier in ksignal */ 375 SIGADDSET(p->p_sigignore, sig); 376 } 377 SIGDELSET(p->p_sigcatch, sig); 378 } else { 379 SIGDELSET(p->p_sigignore, sig); 380 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 381 SIGDELSET(p->p_sigcatch, sig); 382 else 383 SIGADDSET(p->p_sigcatch, sig); 384 } 385 } 386 lwkt_reltoken(&p->p_token); 387 return (0); 388 } 389 390 int 391 sys_sigaction(struct sysmsg *sysmsg, const struct sigaction_args *uap) 392 { 393 struct sigaction act, oact; 394 struct sigaction *actp, *oactp; 395 int error; 396 397 actp = (uap->act != NULL) ? &act : NULL; 398 oactp = (uap->oact != NULL) ? &oact : NULL; 399 if (actp) { 400 error = copyin(uap->act, actp, sizeof(act)); 401 if (error) 402 return (error); 403 } 404 error = kern_sigaction(uap->sig, actp, oactp); 405 if (oactp && !error) { 406 error = copyout(oactp, uap->oact, sizeof(oact)); 407 } 408 return (error); 409 } 410 411 /* 412 * Initialize signal state for process 0; 413 * set to ignore signals that are ignored by default. 414 */ 415 void 416 siginit(struct proc *p) 417 { 418 int i; 419 420 for (i = 1; i <= NSIG; i++) { 421 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 422 SIGADDSET(p->p_sigignore, i); 423 } 424 425 /* 426 * Also initialize signal-related global state. 427 */ 428 SIGSETOR_CANTMASK(sigcantmask_mask); 429 } 430 431 /* 432 * Reset signals for an exec of the specified process. 433 */ 434 void 435 execsigs(struct proc *p) 436 { 437 struct sigacts *ps = p->p_sigacts; 438 struct lwp *lp; 439 int sig; 440 441 lp = ONLY_LWP_IN_PROC(p); 442 443 /* 444 * Reset caught signals. Held signals remain held 445 * through p_sigmask (unless they were caught, 446 * and are now ignored by default). 447 */ 448 while (SIGNOTEMPTY(p->p_sigcatch)) { 449 sig = sig_ffs(&p->p_sigcatch); 450 SIGDELSET(p->p_sigcatch, sig); 451 if (sigprop(sig) & SA_IGNORE) { 452 if (sig != SIGCONT) 453 SIGADDSET(p->p_sigignore, sig); 454 SIGDELSET_ATOMIC(p->p_siglist, sig); 455 /* don't need spinlock */ 456 SIGDELSET(lp->lwp_siglist, sig); 457 } 458 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 459 } 460 461 /* 462 * Reset stack state to the user stack. 463 * Clear set of signals caught on the signal stack. 464 */ 465 lp->lwp_sigstk.ss_flags = SS_DISABLE; 466 lp->lwp_sigstk.ss_size = 0; 467 lp->lwp_sigstk.ss_sp = NULL; 468 lp->lwp_flags &= ~LWP_ALTSTACK; 469 /* 470 * Reset no zombies if child dies flag as Solaris does. 471 */ 472 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 473 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 474 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 475 } 476 477 /* 478 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 479 * 480 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 481 * p == curproc. 482 */ 483 int 484 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 485 { 486 struct thread *td = curthread; 487 struct lwp *lp = td->td_lwp; 488 struct proc *p = td->td_proc; 489 int error; 490 491 lwkt_gettoken(&p->p_token); 492 493 if (oset != NULL) 494 *oset = lp->lwp_sigmask; 495 496 error = 0; 497 if (set != NULL) { 498 switch (how) { 499 case SIG_BLOCK: 500 SIG_CANTMASK(*set); 501 SIGSETOR(lp->lwp_sigmask, *set); 502 break; 503 case SIG_UNBLOCK: 504 SIGSETNAND(lp->lwp_sigmask, *set); 505 break; 506 case SIG_SETMASK: 507 SIG_CANTMASK(*set); 508 lp->lwp_sigmask = *set; 509 break; 510 default: 511 error = EINVAL; 512 break; 513 } 514 } 515 516 lwkt_reltoken(&p->p_token); 517 518 return (error); 519 } 520 521 /* 522 * sigprocmask() 523 * 524 * MPSAFE 525 */ 526 int 527 sys_sigprocmask(struct sysmsg *sysmsg, const struct sigprocmask_args *uap) 528 { 529 sigset_t set, oset; 530 sigset_t *setp, *osetp; 531 int error; 532 533 setp = (uap->set != NULL) ? &set : NULL; 534 osetp = (uap->oset != NULL) ? &oset : NULL; 535 if (setp) { 536 error = copyin(uap->set, setp, sizeof(set)); 537 if (error) 538 return (error); 539 } 540 error = kern_sigprocmask(uap->how, setp, osetp); 541 if (osetp && !error) { 542 error = copyout(osetp, uap->oset, sizeof(oset)); 543 } 544 return (error); 545 } 546 547 /* 548 * MPSAFE 549 */ 550 int 551 kern_sigpending(sigset_t *set) 552 { 553 struct lwp *lp = curthread->td_lwp; 554 555 *set = lwp_sigpend(lp); 556 557 return (0); 558 } 559 560 /* 561 * MPSAFE 562 */ 563 int 564 sys_sigpending(struct sysmsg *sysmsg, const struct sigpending_args *uap) 565 { 566 sigset_t set; 567 int error; 568 569 error = kern_sigpending(&set); 570 571 if (error == 0) 572 error = copyout(&set, uap->set, sizeof(set)); 573 return (error); 574 } 575 576 /* 577 * Suspend process until signal, providing mask to be set 578 * in the meantime. 579 * 580 * MPSAFE 581 */ 582 int 583 kern_sigsuspend(sigset_t *set) 584 { 585 struct thread *td = curthread; 586 struct lwp *lp = td->td_lwp; 587 struct proc *p = td->td_proc; 588 struct sigacts *ps = p->p_sigacts; 589 590 /* 591 * When returning from sigsuspend, we want 592 * the old mask to be restored after the 593 * signal handler has finished. Thus, we 594 * save it here and mark the sigacts structure 595 * to indicate this. 596 */ 597 lp->lwp_oldsigmask = lp->lwp_sigmask; 598 lp->lwp_flags |= LWP_OLDMASK; 599 600 SIG_CANTMASK(*set); 601 lp->lwp_sigmask = *set; 602 while (tsleep(ps, PCATCH, "pause", 0) == 0) 603 /* void */; 604 /* always return EINTR rather than ERESTART... */ 605 return (EINTR); 606 } 607 608 /* 609 * Note nonstandard calling convention: libc stub passes mask, not 610 * pointer, to save a copyin. 611 * 612 * MPSAFE 613 */ 614 int 615 sys_sigsuspend(struct sysmsg *sysmsg, const struct sigsuspend_args *uap) 616 { 617 sigset_t mask; 618 int error; 619 620 error = copyin(uap->sigmask, &mask, sizeof(mask)); 621 if (error) 622 return (error); 623 624 error = kern_sigsuspend(&mask); 625 626 return (error); 627 } 628 629 /* 630 * MPSAFE 631 */ 632 int 633 kern_sigaltstack(stack_t *ss, stack_t *oss) 634 { 635 struct thread *td = curthread; 636 struct lwp *lp = td->td_lwp; 637 struct proc *p = td->td_proc; 638 639 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 640 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 641 642 if (oss) 643 *oss = lp->lwp_sigstk; 644 645 if (ss) { 646 if (ss->ss_flags & ~SS_DISABLE) 647 return (EINVAL); 648 if (ss->ss_flags & SS_DISABLE) { 649 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 650 return (EPERM); 651 lp->lwp_flags &= ~LWP_ALTSTACK; 652 lp->lwp_sigstk.ss_flags = ss->ss_flags; 653 } else { 654 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 655 return (ENOMEM); 656 lp->lwp_flags |= LWP_ALTSTACK; 657 lp->lwp_sigstk = *ss; 658 } 659 } 660 661 return (0); 662 } 663 664 /* 665 * MPSAFE 666 */ 667 int 668 sys_sigaltstack(struct sysmsg *sysmsg, const struct sigaltstack_args *uap) 669 { 670 stack_t ss, oss; 671 int error; 672 673 if (uap->ss) { 674 error = copyin(uap->ss, &ss, sizeof(ss)); 675 if (error) 676 return (error); 677 } 678 679 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); 680 681 if (error == 0 && uap->oss) 682 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 683 return (error); 684 } 685 686 /* 687 * Common code for kill process group/broadcast kill. 688 * cp is calling process. 689 */ 690 struct killpg_info { 691 int nfound; 692 int sig; 693 }; 694 695 static int killpg_all_callback(struct proc *p, void *data); 696 697 static int 698 dokillpg(int sig, int pgid, int all) 699 { 700 struct killpg_info info; 701 struct proc *cp = curproc; 702 struct proc *p; 703 struct pgrp *pgrp; 704 705 info.nfound = 0; 706 info.sig = sig; 707 708 if (all) { 709 /* 710 * broadcast 711 */ 712 allproc_scan(killpg_all_callback, &info, 0); 713 } else { 714 if (pgid == 0) { 715 /* 716 * zero pgid means send to my process group. 717 */ 718 pgrp = cp->p_pgrp; 719 pgref(pgrp); 720 } else { 721 pgrp = pgfind(pgid); 722 if (pgrp == NULL) 723 return (ESRCH); 724 } 725 726 /* 727 * Must interlock all signals against fork 728 */ 729 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 730 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 731 if (p->p_pid <= 1 || 732 p->p_stat == SZOMB || 733 (p->p_flags & P_SYSTEM) || 734 !CANSIGNAL(p, sig, 0)) { 735 continue; 736 } 737 ++info.nfound; 738 if (sig) 739 ksignal(p, sig); 740 } 741 lockmgr(&pgrp->pg_lock, LK_RELEASE); 742 pgrel(pgrp); 743 } 744 return (info.nfound ? 0 : ESRCH); 745 } 746 747 static int 748 killpg_all_callback(struct proc *p, void *data) 749 { 750 struct killpg_info *info = data; 751 752 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 753 p == curproc || !CANSIGNAL(p, info->sig, 0)) { 754 return (0); 755 } 756 ++info->nfound; 757 if (info->sig) 758 ksignal(p, info->sig); 759 return(0); 760 } 761 762 /* 763 * Send a general signal to a process or LWPs within that process. 764 * 765 * Note that new signals cannot be sent if a process is exiting or already 766 * a zombie, but we return success anyway as userland is likely to not handle 767 * the race properly. 768 * 769 * No requirements. 770 */ 771 int 772 kern_kill(int sig, pid_t pid, lwpid_t tid) 773 { 774 int t; 775 776 if ((u_int)sig >= _SIG_MAXSIG) 777 return (EINVAL); 778 779 if (pid > 0) { 780 struct proc *p; 781 struct lwp *lp = NULL; 782 783 /* 784 * Send a signal to a single process. If the kill() is 785 * racing an exiting process which has not yet been reaped 786 * act as though the signal was delivered successfully but 787 * don't actually try to deliver the signal. 788 */ 789 if ((p = pfind(pid)) == NULL) { 790 if ((p = zpfind(pid)) == NULL) 791 return (ESRCH); 792 PRELE(p); 793 return (0); 794 } 795 if (p != curproc) { 796 lwkt_gettoken_shared(&p->p_token); 797 if (!CANSIGNAL(p, sig, 1)) { 798 lwkt_reltoken(&p->p_token); 799 PRELE(p); 800 return (EPERM); 801 } 802 lwkt_reltoken(&p->p_token); 803 } 804 805 /* 806 * NOP if the process is exiting. Note that lwpsignal() is 807 * called directly with P_WEXIT set to kill individual LWPs 808 * during exit, which is allowed. 809 */ 810 if (p->p_flags & P_WEXIT) { 811 PRELE(p); 812 return (0); 813 } 814 if (tid != -1) { 815 lwkt_gettoken_shared(&p->p_token); 816 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 817 if (lp == NULL) { 818 lwkt_reltoken(&p->p_token); 819 PRELE(p); 820 return (ESRCH); 821 } 822 LWPHOLD(lp); 823 lwkt_reltoken(&p->p_token); 824 } 825 if (sig) 826 lwpsignal(p, lp, sig); 827 if (lp) 828 LWPRELE(lp); 829 PRELE(p); 830 831 return (0); 832 } 833 834 /* 835 * If we come here, pid is a special broadcast pid. 836 * This doesn't mix with a tid. 837 */ 838 if (tid != -1) 839 return (EINVAL); 840 841 switch (pid) { 842 case -1: /* broadcast signal */ 843 t = (dokillpg(sig, 0, 1)); 844 break; 845 case 0: /* signal own process group */ 846 t = (dokillpg(sig, 0, 0)); 847 break; 848 default: /* negative explicit process group */ 849 t = (dokillpg(sig, -pid, 0)); 850 break; 851 } 852 return t; 853 } 854 855 int 856 sys_kill(struct sysmsg *sysmsg, const struct kill_args *uap) 857 { 858 int error; 859 860 error = kern_kill(uap->signum, uap->pid, -1); 861 return (error); 862 } 863 864 int 865 sys_lwp_kill(struct sysmsg *sysmsg, const struct lwp_kill_args *uap) 866 { 867 int error; 868 pid_t pid = uap->pid; 869 870 /* 871 * A tid is mandatory for lwp_kill(), otherwise 872 * you could simply use kill(). 873 */ 874 if (uap->tid == -1) 875 return (EINVAL); 876 877 /* 878 * To save on a getpid() function call for intra-process 879 * signals, pid == -1 means current process. 880 */ 881 if (pid == -1) 882 pid = curproc->p_pid; 883 884 error = kern_kill(uap->signum, pid, uap->tid); 885 return (error); 886 } 887 888 /* 889 * Send a signal to a process group. 890 */ 891 void 892 gsignal(int pgid, int sig) 893 { 894 struct pgrp *pgrp; 895 896 if (pgid && (pgrp = pgfind(pgid))) 897 pgsignal(pgrp, sig, 0); 898 } 899 900 /* 901 * Send a signal to a process group. If checktty is 1, 902 * limit to members which have a controlling terminal. 903 * 904 * pg_lock interlocks against a fork that might be in progress, to 905 * ensure that the new child process picks up the signal. 906 */ 907 void 908 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 909 { 910 struct proc *p; 911 912 /* 913 * Must interlock all signals against fork 914 */ 915 if (pgrp) { 916 pgref(pgrp); 917 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 918 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 919 if (checkctty == 0 || p->p_flags & P_CONTROLT) 920 ksignal(p, sig); 921 } 922 lockmgr(&pgrp->pg_lock, LK_RELEASE); 923 pgrel(pgrp); 924 } 925 } 926 927 /* 928 * Send a signal caused by a trap to the current lwp. If it will be caught 929 * immediately, deliver it with correct code. Otherwise, post it normally. 930 * 931 * These signals may ONLY be delivered to the specified lwp and may never 932 * be delivered to the process generically. 933 * 934 * lpmap->blockallsigs is ignored. 935 */ 936 void 937 trapsignal(struct lwp *lp, int sig, u_long code) 938 { 939 struct proc *p = lp->lwp_proc; 940 struct sigacts *ps = p->p_sigacts; 941 942 /* 943 * If we are a virtual kernel running an emulated user process 944 * context, switch back to the virtual kernel context before 945 * trying to post the signal. 946 */ 947 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 948 struct trapframe *tf = lp->lwp_md.md_regs; 949 tf->tf_trapno = 0; 950 vkernel_trap(lp, tf); 951 } 952 953 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 954 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 955 lp->lwp_ru.ru_nsignals++; 956 #ifdef KTRACE 957 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 958 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 959 &lp->lwp_sigmask, code); 960 #endif 961 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 962 &lp->lwp_sigmask, code); 963 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 964 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 965 SIGADDSET(lp->lwp_sigmask, sig); 966 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 967 /* 968 * See kern_sigaction() for origin of this code. 969 */ 970 SIGDELSET(p->p_sigcatch, sig); 971 if (sig != SIGCONT && 972 sigprop(sig) & SA_IGNORE) 973 SIGADDSET(p->p_sigignore, sig); 974 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 975 } 976 } else { 977 lp->lwp_code = code; /* XXX for core dump/debugger */ 978 lp->lwp_sig = sig; /* XXX to verify code */ 979 lwpsignal(p, lp, sig); 980 } 981 } 982 983 /* 984 * Find a suitable lwp to deliver the signal to. Returns NULL if all 985 * lwps hold the signal blocked. 986 * 987 * Caller must hold p->p_token. 988 * 989 * Returns a lp or NULL. If non-NULL the lp is held and its token is 990 * acquired. 991 */ 992 static struct lwp * 993 find_lwp_for_signal(struct proc *p, int sig) 994 { 995 struct lwp *lp; 996 struct lwp *run, *sleep, *stop; 997 998 /* 999 * If the running/preempted thread belongs to the proc to which 1000 * the signal is being delivered and this thread does not block 1001 * the signal, then we can avoid a context switch by delivering 1002 * the signal to this thread, because it will return to userland 1003 * soon anyways. 1004 */ 1005 lp = lwkt_preempted_proc(); 1006 if (lp != NULL && lp->lwp_proc == p) { 1007 LWPHOLD(lp); 1008 lwkt_gettoken(&lp->lwp_token); 1009 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 1010 /* return w/ token held */ 1011 return (lp); 1012 } 1013 lwkt_reltoken(&lp->lwp_token); 1014 LWPRELE(lp); 1015 } 1016 1017 run = sleep = stop = NULL; 1018 FOREACH_LWP_IN_PROC(lp, p) { 1019 /* 1020 * If the signal is being blocked by the lwp, then this 1021 * lwp is not eligible for receiving the signal. 1022 */ 1023 LWPHOLD(lp); 1024 lwkt_gettoken(&lp->lwp_token); 1025 1026 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1027 lwkt_reltoken(&lp->lwp_token); 1028 LWPRELE(lp); 1029 continue; 1030 } 1031 1032 switch (lp->lwp_stat) { 1033 case LSRUN: 1034 if (sleep) { 1035 lwkt_token_swap(); 1036 lwkt_reltoken(&sleep->lwp_token); 1037 LWPRELE(sleep); 1038 sleep = NULL; 1039 run = lp; 1040 } else if (stop) { 1041 lwkt_token_swap(); 1042 lwkt_reltoken(&stop->lwp_token); 1043 LWPRELE(stop); 1044 stop = NULL; 1045 run = lp; 1046 } else { 1047 run = lp; 1048 } 1049 break; 1050 case LSSLEEP: 1051 if (lp->lwp_flags & LWP_SINTR) { 1052 if (sleep) { 1053 lwkt_reltoken(&lp->lwp_token); 1054 LWPRELE(lp); 1055 } else if (stop) { 1056 lwkt_token_swap(); 1057 lwkt_reltoken(&stop->lwp_token); 1058 LWPRELE(stop); 1059 stop = NULL; 1060 sleep = lp; 1061 } else { 1062 sleep = lp; 1063 } 1064 } else { 1065 lwkt_reltoken(&lp->lwp_token); 1066 LWPRELE(lp); 1067 } 1068 break; 1069 case LSSTOP: 1070 if (sleep) { 1071 lwkt_reltoken(&lp->lwp_token); 1072 LWPRELE(lp); 1073 } else if (stop) { 1074 lwkt_reltoken(&lp->lwp_token); 1075 LWPRELE(lp); 1076 } else { 1077 stop = lp; 1078 } 1079 break; 1080 } 1081 if (run) 1082 break; 1083 } 1084 1085 if (run != NULL) 1086 return (run); 1087 else if (sleep != NULL) 1088 return (sleep); 1089 else 1090 return (stop); 1091 } 1092 1093 /* 1094 * Send the signal to the process. If the signal has an action, the action 1095 * is usually performed by the target process rather than the caller; we add 1096 * the signal to the set of pending signals for the process. 1097 * 1098 * Exceptions: 1099 * o When a stop signal is sent to a sleeping process that takes the 1100 * default action, the process is stopped without awakening it. 1101 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1102 * regardless of the signal action (eg, blocked or ignored). 1103 * 1104 * Other ignored signals are discarded immediately. 1105 * 1106 * If the caller wishes to call this function from a hard code section the 1107 * caller must already hold p->p_token (see kern_clock.c). 1108 * 1109 * No requirements. 1110 */ 1111 void 1112 ksignal(struct proc *p, int sig) 1113 { 1114 lwpsignal(p, NULL, sig); 1115 } 1116 1117 /* 1118 * The core for ksignal. lp may be NULL, then a suitable thread 1119 * will be chosen. If not, lp MUST be a member of p. 1120 * 1121 * If the caller wishes to call this function from a hard code section the 1122 * caller must already hold p->p_token. 1123 * 1124 * No requirements. 1125 */ 1126 void 1127 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1128 { 1129 struct proc *q; 1130 sig_t action; 1131 int prop; 1132 1133 if (sig >= _SIG_MAXSIG || sig <= 0) { 1134 kprintf("lwpsignal: signal %d\n", sig); 1135 panic("lwpsignal signal number"); 1136 } 1137 1138 KKASSERT(lp == NULL || lp->lwp_proc == p); 1139 1140 /* 1141 * We don't want to race... well, all sorts of things. Get appropriate 1142 * tokens. 1143 * 1144 * Don't try to deliver a generic signal to an exiting process, 1145 * the signal structures could be in flux. We check the LWP later 1146 * on. 1147 */ 1148 PHOLD(p); 1149 if (lp) { 1150 LWPHOLD(lp); 1151 lwkt_gettoken(&lp->lwp_token); 1152 } else { 1153 lwkt_gettoken(&p->p_token); 1154 if (p->p_flags & P_WEXIT) 1155 goto out; 1156 } 1157 1158 prop = sigprop(sig); 1159 1160 /* 1161 * If proc is traced, always give parent a chance; 1162 * if signal event is tracked by procfs, give *that* 1163 * a chance, as well. 1164 */ 1165 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1166 action = SIG_DFL; 1167 } else { 1168 /* 1169 * Do not try to deliver signals to an exiting lwp other 1170 * than SIGKILL. Note that we must still deliver the signal 1171 * if P_WEXIT is set in the process flags. 1172 */ 1173 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { 1174 lwkt_reltoken(&lp->lwp_token); 1175 LWPRELE(lp); 1176 PRELE(p); 1177 return; 1178 } 1179 1180 /* 1181 * If the signal is being ignored, then we forget about 1182 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1183 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1184 */ 1185 if (SIGISMEMBER(p->p_sigignore, sig)) { 1186 /* 1187 * Even if a signal is set SIG_IGN, it may still be 1188 * lurking in a kqueue. 1189 */ 1190 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1191 if (lp) { 1192 lwkt_reltoken(&lp->lwp_token); 1193 LWPRELE(lp); 1194 } else { 1195 lwkt_reltoken(&p->p_token); 1196 } 1197 PRELE(p); 1198 return; 1199 } 1200 if (SIGISMEMBER(p->p_sigcatch, sig)) 1201 action = SIG_CATCH; 1202 else 1203 action = SIG_DFL; 1204 } 1205 1206 /* 1207 * If continuing, clear any pending STOP signals for the whole 1208 * process. 1209 */ 1210 if (prop & SA_CONT) { 1211 lwkt_gettoken(&p->p_token); 1212 SIG_STOPSIGMASK_ATOMIC(p->p_siglist); 1213 lwkt_reltoken(&p->p_token); 1214 } 1215 1216 if (prop & SA_STOP) { 1217 /* 1218 * If sending a tty stop signal to a member of an orphaned 1219 * process group, discard the signal here if the action 1220 * is default; don't stop the process below if sleeping, 1221 * and don't clear any pending SIGCONT. 1222 */ 1223 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && 1224 action == SIG_DFL) { 1225 if (lp) { 1226 lwkt_reltoken(&lp->lwp_token); 1227 LWPRELE(lp); 1228 } else { 1229 lwkt_reltoken(&p->p_token); 1230 } 1231 PRELE(p); 1232 return; 1233 } 1234 lwkt_gettoken(&p->p_token); 1235 SIG_CONTSIGMASK_ATOMIC(p->p_siglist); 1236 p->p_flags &= ~P_CONTINUED; 1237 lwkt_reltoken(&p->p_token); 1238 } 1239 1240 if (p->p_stat == SSTOP) { 1241 /* 1242 * Nobody can handle this signal, add it to the lwp or 1243 * process pending list 1244 */ 1245 lwkt_gettoken(&p->p_token); 1246 if (p->p_stat != SSTOP) { 1247 lwkt_reltoken(&p->p_token); 1248 goto not_stopped; 1249 } 1250 sigsetfrompid(curthread, p, sig); 1251 if (lp) { 1252 spin_lock(&lp->lwp_spin); 1253 SIGADDSET(lp->lwp_siglist, sig); 1254 spin_unlock(&lp->lwp_spin); 1255 } else { 1256 SIGADDSET_ATOMIC(p->p_siglist, sig); 1257 } 1258 1259 /* 1260 * If the process is stopped and is being traced, then no 1261 * further action is necessary. 1262 */ 1263 if (p->p_flags & P_TRACED) { 1264 lwkt_reltoken(&p->p_token); 1265 goto out; 1266 } 1267 1268 /* 1269 * If the process is stopped and receives a KILL signal, 1270 * make the process runnable. 1271 */ 1272 if (sig == SIGKILL) { 1273 proc_unstop(p, SSTOP); 1274 lwkt_reltoken(&p->p_token); 1275 goto active_process; 1276 } 1277 1278 /* 1279 * If the process is stopped and receives a CONT signal, 1280 * then try to make the process runnable again. 1281 */ 1282 if (prop & SA_CONT) { 1283 /* 1284 * If SIGCONT is default (or ignored), we continue the 1285 * process but don't leave the signal in p_siglist, as 1286 * it has no further action. If SIGCONT is held, we 1287 * continue the process and leave the signal in 1288 * p_siglist. If the process catches SIGCONT, let it 1289 * handle the signal itself. 1290 * 1291 * XXX what if the signal is being held blocked? 1292 * 1293 * Token required to interlock kern_wait(). 1294 * Reparenting can also cause a race so we have to 1295 * hold (q). 1296 */ 1297 q = p->p_pptr; 1298 PHOLD(q); 1299 lwkt_gettoken(&q->p_token); 1300 p->p_flags |= P_CONTINUED; 1301 wakeup(q); 1302 if (action == SIG_DFL) 1303 SIGDELSET_ATOMIC(p->p_siglist, sig); 1304 proc_unstop(p, SSTOP); 1305 lwkt_reltoken(&q->p_token); 1306 PRELE(q); 1307 lwkt_reltoken(&p->p_token); 1308 if (action == SIG_CATCH) 1309 goto active_process; 1310 goto out; 1311 } 1312 1313 /* 1314 * If the process is stopped and receives another STOP 1315 * signal, we do not need to stop it again. If we did 1316 * the shell could get confused. 1317 * 1318 * However, if the current/preempted lwp is part of the 1319 * process receiving the signal, we need to keep it, 1320 * so that this lwp can stop in issignal() later, as 1321 * we don't want to wait until it reaches userret! 1322 */ 1323 if (prop & SA_STOP) { 1324 if (lwkt_preempted_proc() == NULL || 1325 lwkt_preempted_proc()->lwp_proc != p) { 1326 SIGDELSET_ATOMIC(p->p_siglist, sig); 1327 } 1328 } 1329 1330 /* 1331 * Otherwise the process is stopped and it received some 1332 * signal, which does not change its stopped state. When 1333 * the process is continued a wakeup(p) will be issued which 1334 * will wakeup any threads sleeping in tstop(). 1335 */ 1336 lwkt_reltoken(&p->p_token); 1337 goto out; 1338 /* NOTREACHED */ 1339 } 1340 not_stopped: 1341 ; 1342 /* else not stopped */ 1343 active_process: 1344 1345 /* 1346 * Never deliver a lwp-specific signal to a random lwp. 1347 */ 1348 if (lp == NULL) { 1349 /* NOTE: returns lp w/ token held */ 1350 lp = find_lwp_for_signal(p, sig); 1351 if (lp) { 1352 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1353 lwkt_reltoken(&lp->lwp_token); 1354 LWPRELE(lp); 1355 lp = NULL; 1356 /* maintain proc token */ 1357 } else { 1358 lwkt_token_swap(); 1359 lwkt_reltoken(&p->p_token); 1360 /* maintain lp token */ 1361 } 1362 } 1363 } 1364 1365 /* 1366 * Deliver to the process generically if (1) the signal is being 1367 * sent to any thread or (2) we could not find a thread to deliver 1368 * it to. 1369 */ 1370 if (lp == NULL) { 1371 sigsetfrompid(curthread, p, sig); 1372 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1373 SIGADDSET_ATOMIC(p->p_siglist, sig); 1374 goto out; 1375 } 1376 1377 /* 1378 * Deliver to a specific LWP whether it masks it or not. It will 1379 * not be dispatched if masked but we must still deliver it. 1380 */ 1381 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1382 (p->p_flags & P_TRACED) == 0) { 1383 lwkt_gettoken(&p->p_token); 1384 p->p_nice = NZERO; 1385 lwkt_reltoken(&p->p_token); 1386 } 1387 1388 /* 1389 * If the process receives a STOP signal which indeed needs to 1390 * stop the process, do so. If the process chose to catch the 1391 * signal, it will be treated like any other signal. 1392 */ 1393 if ((prop & SA_STOP) && action == SIG_DFL) { 1394 /* 1395 * If a child holding parent blocked, stopping 1396 * could cause deadlock. Take no action at this 1397 * time. 1398 */ 1399 lwkt_gettoken(&p->p_token); 1400 if (p->p_flags & P_PPWAIT) { 1401 sigsetfrompid(curthread, p, sig); 1402 SIGADDSET_ATOMIC(p->p_siglist, sig); 1403 lwkt_reltoken(&p->p_token); 1404 goto out; 1405 } 1406 1407 /* 1408 * Do not actually try to manipulate the process, but simply 1409 * stop it. Lwps will stop as soon as they safely can. 1410 * 1411 * Ignore stop if the process is exiting. 1412 */ 1413 if ((p->p_flags & P_WEXIT) == 0) { 1414 p->p_xstat = sig; 1415 proc_stop(p, SSTOP); 1416 } 1417 lwkt_reltoken(&p->p_token); 1418 goto out; 1419 } 1420 1421 /* 1422 * If it is a CONT signal with default action, just ignore it. 1423 */ 1424 if ((prop & SA_CONT) && action == SIG_DFL) 1425 goto out; 1426 1427 /* 1428 * Mark signal pending at this specific thread. 1429 */ 1430 sigsetfrompid(curthread, p, sig); 1431 spin_lock(&lp->lwp_spin); 1432 SIGADDSET(lp->lwp_siglist, sig); 1433 spin_unlock(&lp->lwp_spin); 1434 1435 lwp_signotify(lp); 1436 1437 out: 1438 if (lp) { 1439 lwkt_reltoken(&lp->lwp_token); 1440 LWPRELE(lp); 1441 } else { 1442 lwkt_reltoken(&p->p_token); 1443 } 1444 PRELE(p); 1445 } 1446 1447 /* 1448 * Notify the LWP that a signal has arrived. The LWP does not have to be 1449 * sleeping on the current cpu. 1450 * 1451 * p->p_token and lp->lwp_token must be held on call. 1452 * 1453 * We can only safely schedule the thread on its current cpu and only if 1454 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1455 * the correct cpu we are properly interlocked, otherwise we could be 1456 * racing other thread transition states (or the lwp is on the user scheduler 1457 * runq but not scheduled) and must not do anything. 1458 * 1459 * Since we hold the lwp token we know the lwp cannot be ripped out from 1460 * under us so we can safely hold it to prevent it from being ripped out 1461 * from under us if we are forced to IPI another cpu to make the local 1462 * checks there. 1463 * 1464 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1465 * which we won't in an IPI so any fixups have to be done here, effectively 1466 * replicating part of what setrunnable() does. 1467 */ 1468 static void 1469 lwp_signotify(struct lwp *lp) 1470 { 1471 thread_t dtd; 1472 1473 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1474 dtd = lp->lwp_thread; 1475 1476 crit_enter(); 1477 if (lp == lwkt_preempted_proc()) { 1478 /* 1479 * lwp is on the current cpu AND it is currently running 1480 * (we preempted it). 1481 */ 1482 signotify(); 1483 } else if (lp->lwp_flags & LWP_SINTR) { 1484 /* 1485 * lwp is sitting in tsleep() with PCATCH set 1486 */ 1487 if (dtd->td_gd == mycpu) { 1488 setrunnable(lp); 1489 } else { 1490 /* 1491 * We can only adjust lwp_stat while we hold the 1492 * lwp_token, and we won't in the IPI function. 1493 */ 1494 LWPHOLD(lp); 1495 if (lp->lwp_stat == LSSTOP) 1496 lp->lwp_stat = LSSLEEP; 1497 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1498 } 1499 } else if (dtd->td_flags & TDF_SINTR) { 1500 /* 1501 * lwp is sitting in lwkt_sleep() with PCATCH set. 1502 */ 1503 if (dtd->td_gd == mycpu) { 1504 setrunnable(lp); 1505 } else { 1506 /* 1507 * We can only adjust lwp_stat while we hold the 1508 * lwp_token, and we won't in the IPI function. 1509 */ 1510 LWPHOLD(lp); 1511 if (lp->lwp_stat == LSSTOP) 1512 lp->lwp_stat = LSSLEEP; 1513 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1514 } 1515 } else { 1516 /* 1517 * Otherwise the lwp is either in some uninterruptible state 1518 * or it is on the userland scheduler's runqueue waiting to 1519 * be scheduled to a cpu, or it is running in userland. We 1520 * generally want to send an IPI so a running target gets the 1521 * signal ASAP, otherwise a scheduler-tick worth of latency 1522 * will occur. 1523 * 1524 * Issue an IPI to the remote cpu to knock it into the kernel, 1525 * remote cpu will issue the cpu-local signotify() if the IPI 1526 * preempts the desired thread. 1527 */ 1528 if (dtd->td_gd != mycpu) { 1529 LWPHOLD(lp); 1530 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1531 } 1532 } 1533 crit_exit(); 1534 } 1535 1536 /* 1537 * This function is called via an IPI so we cannot call setrunnable() here 1538 * (because while we hold the lp we don't own its token, and can't get it 1539 * from an IPI). 1540 * 1541 * We are interlocked by virtue of being on the same cpu as the target. If 1542 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1543 * the target thread. 1544 */ 1545 static void 1546 lwp_signotify_remote(void *arg) 1547 { 1548 struct lwp *lp = arg; 1549 thread_t td = lp->lwp_thread; 1550 1551 if (lp == lwkt_preempted_proc()) { 1552 signotify(); 1553 LWPRELE(lp); 1554 } else if (td->td_gd == mycpu) { 1555 if ((lp->lwp_flags & LWP_SINTR) || 1556 (td->td_flags & TDF_SINTR)) { 1557 lwkt_schedule(td); 1558 } 1559 LWPRELE(lp); 1560 } else { 1561 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1562 /* LWPHOLD() is forwarded to the target cpu */ 1563 } 1564 } 1565 1566 /* 1567 * Caller must hold p->p_token 1568 */ 1569 void 1570 proc_stop(struct proc *p, int sig) 1571 { 1572 struct proc *q; 1573 struct lwp *lp; 1574 1575 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1576 1577 /* 1578 * If somebody raced us, be happy with it. SCORE overrides SSTOP. 1579 */ 1580 if (sig == SCORE) { 1581 if (p->p_stat == SCORE || p->p_stat == SZOMB) 1582 return; 1583 } else { 1584 if (p->p_stat == SSTOP || p->p_stat == SCORE || 1585 p->p_stat == SZOMB) { 1586 return; 1587 } 1588 } 1589 p->p_stat = sig; 1590 1591 FOREACH_LWP_IN_PROC(lp, p) { 1592 LWPHOLD(lp); 1593 lwkt_gettoken(&lp->lwp_token); 1594 1595 switch (lp->lwp_stat) { 1596 case LSSTOP: 1597 /* 1598 * Do nothing, we are already counted in 1599 * p_nstopped. 1600 */ 1601 break; 1602 1603 case LSSLEEP: 1604 /* 1605 * We're sleeping, but we will stop before 1606 * returning to userspace, so count us 1607 * as stopped as well. We set LWP_MP_WSTOP 1608 * to signal the lwp that it should not 1609 * increase p_nstopped when reaching tstop(). 1610 * 1611 * LWP_MP_WSTOP is protected by lp->lwp_token. 1612 */ 1613 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1614 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1615 ++p->p_nstopped; 1616 } 1617 break; 1618 1619 case LSRUN: 1620 /* 1621 * We might notify ourself, but that's not 1622 * a problem. 1623 */ 1624 lwp_signotify(lp); 1625 break; 1626 } 1627 lwkt_reltoken(&lp->lwp_token); 1628 LWPRELE(lp); 1629 } 1630 1631 if (p->p_nstopped == p->p_nthreads) { 1632 /* 1633 * Token required to interlock kern_wait(). Reparenting can 1634 * also cause a race so we have to hold (q). 1635 */ 1636 q = p->p_pptr; 1637 PHOLD(q); 1638 lwkt_gettoken(&q->p_token); 1639 p->p_flags &= ~P_WAITED; 1640 wakeup(q); 1641 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1642 ksignal(p->p_pptr, SIGCHLD); 1643 lwkt_reltoken(&q->p_token); 1644 PRELE(q); 1645 } 1646 } 1647 1648 /* 1649 * Caller must hold p_token 1650 */ 1651 void 1652 proc_unstop(struct proc *p, int sig) 1653 { 1654 struct lwp *lp; 1655 1656 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1657 1658 if (p->p_stat != sig) 1659 return; 1660 1661 p->p_stat = SACTIVE; 1662 1663 FOREACH_LWP_IN_PROC(lp, p) { 1664 LWPHOLD(lp); 1665 lwkt_gettoken(&lp->lwp_token); 1666 1667 switch (lp->lwp_stat) { 1668 case LSRUN: 1669 /* 1670 * Uh? Not stopped? Well, I guess that's okay. 1671 */ 1672 if (bootverbose) 1673 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1674 p->p_pid, lp->lwp_tid); 1675 break; 1676 1677 case LSSLEEP: 1678 /* 1679 * Still sleeping. Don't bother waking it up. 1680 * However, if this thread was counted as 1681 * stopped, undo this. 1682 * 1683 * Nevertheless we call setrunnable() so that it 1684 * will wake up in case a signal or timeout arrived 1685 * in the meantime. 1686 * 1687 * LWP_MP_WSTOP is protected by lp->lwp_token. 1688 */ 1689 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1690 atomic_clear_int(&lp->lwp_mpflags, 1691 LWP_MP_WSTOP); 1692 --p->p_nstopped; 1693 } else { 1694 if (bootverbose) 1695 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1696 p->p_pid, lp->lwp_tid); 1697 } 1698 /* FALLTHROUGH */ 1699 1700 case LSSTOP: 1701 /* 1702 * This handles any lwp's waiting in a tsleep with 1703 * SIGCATCH. 1704 */ 1705 lwp_signotify(lp); 1706 break; 1707 1708 } 1709 lwkt_reltoken(&lp->lwp_token); 1710 LWPRELE(lp); 1711 } 1712 1713 /* 1714 * This handles any lwp's waiting in tstop(). We have interlocked 1715 * the setting of p_stat by acquiring and releasing each lpw's 1716 * token. 1717 */ 1718 wakeup(p); 1719 } 1720 1721 /* 1722 * Wait for all threads except the current thread to stop. 1723 */ 1724 static void 1725 proc_stopwait(struct proc *p) 1726 { 1727 while ((p->p_stat == SSTOP || p->p_stat == SCORE) && 1728 p->p_nstopped < p->p_nthreads - 1) { 1729 tsleep_interlock(&p->p_nstopped, 0); 1730 if (p->p_nstopped < p->p_nthreads - 1) { 1731 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); 1732 } 1733 } 1734 } 1735 1736 /* 1737 * No requirements. 1738 */ 1739 static int 1740 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1741 { 1742 sigset_t savedmask, set; 1743 struct proc *p = curproc; 1744 struct lwp *lp = curthread->td_lwp; 1745 int error, sig, hz, timevalid = 0; 1746 struct timespec rts, ets, ts; 1747 struct timeval tv; 1748 1749 error = 0; 1750 sig = 0; 1751 ets.tv_sec = 0; /* silence compiler warning */ 1752 ets.tv_nsec = 0; /* silence compiler warning */ 1753 SIG_CANTMASK(waitset); 1754 savedmask = lp->lwp_sigmask; 1755 1756 if (timeout) { 1757 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1758 timeout->tv_nsec < 1000000000) { 1759 timevalid = 1; 1760 getnanouptime(&rts); 1761 timespecadd(&rts, timeout, &ets); 1762 } 1763 } 1764 1765 for (;;) { 1766 set = lwp_sigpend(lp); 1767 SIGSETAND(set, waitset); 1768 if ((sig = sig_ffs(&set)) != 0) { 1769 SIGFILLSET(lp->lwp_sigmask); 1770 SIGDELSET(lp->lwp_sigmask, sig); 1771 SIG_CANTMASK(lp->lwp_sigmask); 1772 sig = issignal(lp, 1, 0); 1773 /* 1774 * It may be a STOP signal, in the case, issignal 1775 * returns 0, because we may stop there, and new 1776 * signal can come in, we should restart if we got 1777 * nothing. 1778 */ 1779 if (sig == 0) 1780 continue; 1781 else 1782 break; 1783 } 1784 1785 /* 1786 * Previous checking got nothing, and we retried but still 1787 * got nothing, we should return the error status. 1788 */ 1789 if (error) 1790 break; 1791 1792 /* 1793 * POSIX says this must be checked after looking for pending 1794 * signals. 1795 */ 1796 if (timeout) { 1797 if (timevalid == 0) { 1798 error = EINVAL; 1799 break; 1800 } 1801 getnanouptime(&rts); 1802 if (timespeccmp(&rts, &ets, >=)) { 1803 error = EAGAIN; 1804 break; 1805 } 1806 timespecsub(&ets, &rts, &ts); 1807 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1808 hz = tvtohz_high(&tv); 1809 } else { 1810 hz = 0; 1811 } 1812 1813 lp->lwp_sigmask = savedmask; 1814 SIGSETNAND(lp->lwp_sigmask, waitset); 1815 /* 1816 * We won't ever be woken up. Instead, our sleep will 1817 * be broken in lwpsignal(). 1818 */ 1819 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1820 if (timeout) { 1821 if (error == ERESTART) { 1822 /* can not restart a timeout wait. */ 1823 error = EINTR; 1824 } else if (error == EAGAIN) { 1825 /* will calculate timeout by ourself. */ 1826 error = 0; 1827 } 1828 } 1829 /* Retry ... */ 1830 } 1831 1832 lp->lwp_sigmask = savedmask; 1833 if (sig) { 1834 error = 0; 1835 bzero(info, sizeof(*info)); 1836 info->si_signo = sig; 1837 spin_lock(&lp->lwp_spin); 1838 lwp_delsig(lp, sig, 1); /* take the signal! */ 1839 spin_unlock(&lp->lwp_spin); 1840 1841 if (sig == SIGKILL) { 1842 sigexit(lp, sig); 1843 /* NOT REACHED */ 1844 } 1845 } 1846 1847 return (error); 1848 } 1849 1850 /* 1851 * MPALMOSTSAFE 1852 */ 1853 int 1854 sys_sigtimedwait(struct sysmsg *sysmsg, const struct sigtimedwait_args *uap) 1855 { 1856 struct timespec ts; 1857 struct timespec *timeout; 1858 sigset_t set; 1859 siginfo_t info; 1860 int error; 1861 1862 if (uap->timeout) { 1863 error = copyin(uap->timeout, &ts, sizeof(ts)); 1864 if (error) 1865 return (error); 1866 timeout = &ts; 1867 } else { 1868 timeout = NULL; 1869 } 1870 error = copyin(uap->set, &set, sizeof(set)); 1871 if (error) 1872 return (error); 1873 error = kern_sigtimedwait(set, &info, timeout); 1874 if (error) 1875 return (error); 1876 if (uap->info) 1877 error = copyout(&info, uap->info, sizeof(info)); 1878 /* Repost if we got an error. */ 1879 /* 1880 * XXX lwp 1881 * 1882 * This could transform a thread-specific signal to another 1883 * thread / process pending signal. 1884 */ 1885 if (error) { 1886 ksignal(curproc, info.si_signo); 1887 } else { 1888 sysmsg->sysmsg_result = info.si_signo; 1889 } 1890 return (error); 1891 } 1892 1893 /* 1894 * MPALMOSTSAFE 1895 */ 1896 int 1897 sys_sigwaitinfo(struct sysmsg *sysmsg, const struct sigwaitinfo_args *uap) 1898 { 1899 siginfo_t info; 1900 sigset_t set; 1901 int error; 1902 1903 error = copyin(uap->set, &set, sizeof(set)); 1904 if (error) 1905 return (error); 1906 error = kern_sigtimedwait(set, &info, NULL); 1907 if (error) 1908 return (error); 1909 if (uap->info) 1910 error = copyout(&info, uap->info, sizeof(info)); 1911 /* Repost if we got an error. */ 1912 /* 1913 * XXX lwp 1914 * 1915 * This could transform a thread-specific signal to another 1916 * thread / process pending signal. 1917 */ 1918 if (error) { 1919 ksignal(curproc, info.si_signo); 1920 } else { 1921 sysmsg->sysmsg_result = info.si_signo; 1922 } 1923 return (error); 1924 } 1925 1926 /* 1927 * If the current process has received a signal that would interrupt a 1928 * system call, return EINTR or ERESTART as appropriate. 1929 */ 1930 int 1931 iscaught(struct lwp *lp) 1932 { 1933 struct proc *p = lp->lwp_proc; 1934 int sig; 1935 1936 if (p) { 1937 if ((sig = CURSIG(lp)) != 0) { 1938 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1939 return (EINTR); 1940 return (ERESTART); 1941 } 1942 } 1943 return(EWOULDBLOCK); 1944 } 1945 1946 /* 1947 * If the current lwp/proc has received a signal (should be caught or cause 1948 * termination, should interrupt current syscall), return the signal number. 1949 * Stop signals with default action are processed immediately, then cleared; 1950 * they aren't returned. This is checked after each entry to the system for 1951 * a syscall or trap (though this can usually be done without calling issignal 1952 * by checking the pending signal masks in the CURSIG macro). 1953 * 1954 * This routine is called via CURSIG/__cursig. We will acquire and release 1955 * p->p_token but if the caller needs to interlock the test the caller must 1956 * also hold p->p_token. 1957 * 1958 * while (sig = CURSIG(curproc)) 1959 * postsig(sig); 1960 */ 1961 int 1962 issignal(struct lwp *lp, int maytrace, int *ptokp) 1963 { 1964 struct proc *p = lp->lwp_proc; 1965 sigset_t mask; 1966 int sig, prop; 1967 int haveptok; 1968 1969 for (;;) { 1970 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1971 1972 haveptok = 0; 1973 1974 /* 1975 * NOTE: Do not tstop here. Issue the proc_stop() 1976 * so other parties see that we know we need 1977 * to stop, but don't block here. Locks might 1978 * be held. 1979 * 1980 * XXX If this process is supposed to stop, stop this thread. 1981 * removed. 1982 */ 1983 #if 0 1984 if (STOPLWP(p, lp)) { 1985 lwkt_gettoken(&p->p_token); 1986 tstop(); 1987 lwkt_reltoken(&p->p_token); 1988 } 1989 #endif 1990 1991 /* 1992 * Quick check without token 1993 */ 1994 mask = lwp_sigpend(lp); 1995 SIGSETNAND(mask, lp->lwp_sigmask); 1996 if (p->p_flags & P_PPWAIT) 1997 SIG_STOPSIGMASK(mask); 1998 SIG_CONDBLOCKALLSIGS(mask, lp); 1999 2000 if (SIGISEMPTY(mask)) /* no signal to send */ 2001 return (0); 2002 2003 /* 2004 * If the signal is a member of the process signal set 2005 * we need p_token (even if it is also a member of the 2006 * lwp signal set). 2007 */ 2008 sig = sig_ffs(&mask); 2009 if (SIGISMEMBER(p->p_siglist, sig)) { 2010 /* 2011 * Recheck with token 2012 */ 2013 haveptok = 1; 2014 lwkt_gettoken(&p->p_token); 2015 2016 mask = lwp_sigpend(lp); 2017 SIGSETNAND(mask, lp->lwp_sigmask); 2018 if (p->p_flags & P_PPWAIT) 2019 SIG_STOPSIGMASK(mask); 2020 if (SIGISEMPTY(mask)) { /* no signal to send */ 2021 /* haveptok is TRUE */ 2022 lwkt_reltoken(&p->p_token); 2023 return (0); 2024 } 2025 sig = sig_ffs(&mask); 2026 } 2027 2028 STOPEVENT(p, S_SIG, sig); 2029 2030 /* 2031 * We should see pending but ignored signals 2032 * only if P_TRACED was on when they were posted. 2033 */ 2034 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 2035 spin_lock(&lp->lwp_spin); 2036 lwp_delsig(lp, sig, haveptok); 2037 spin_unlock(&lp->lwp_spin); 2038 if (haveptok) 2039 lwkt_reltoken(&p->p_token); 2040 continue; 2041 } 2042 if (maytrace && 2043 (p->p_flags & P_TRACED) && 2044 (p->p_flags & P_PPWAIT) == 0) { 2045 /* 2046 * If traced, always stop, and stay stopped until 2047 * released by the parent. 2048 * 2049 * NOTE: SSTOP may get cleared during the loop, but 2050 * we do not re-notify the parent if we have 2051 * to loop several times waiting for the parent 2052 * to let us continue. XXX not sure if this is 2053 * still true 2054 * 2055 * NOTE: Do not tstop here. Issue the proc_stop() 2056 * so other parties see that we know we need 2057 * to stop, but don't block here. Locks might 2058 * be held. 2059 */ 2060 if (haveptok == 0) { 2061 lwkt_gettoken(&p->p_token); 2062 haveptok = 1; 2063 } 2064 p->p_xstat = sig; 2065 proc_stop(p, SSTOP); 2066 2067 /* 2068 * Normally we don't stop until we return to userland, but 2069 * make an exception when tracing and 'maytrace' is asserted. 2070 */ 2071 if (p->p_flags & P_TRACED) 2072 tstop(); 2073 2074 /* 2075 * If parent wants us to take the signal, 2076 * then it will leave it in p->p_xstat; 2077 * otherwise we just look for signals again. 2078 */ 2079 spin_lock(&lp->lwp_spin); 2080 lwp_delsig(lp, sig, 1); /* clear old signal */ 2081 spin_unlock(&lp->lwp_spin); 2082 sig = p->p_xstat; 2083 if (sig == 0) { 2084 /* haveptok is TRUE */ 2085 lwkt_reltoken(&p->p_token); 2086 continue; 2087 } 2088 2089 /* 2090 * Put the new signal into p_siglist. If the 2091 * signal is being masked, look for other signals. 2092 * 2093 * XXX lwp might need a call to ksignal() 2094 */ 2095 SIGADDSET_ATOMIC(p->p_siglist, sig); 2096 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 2097 /* haveptok is TRUE */ 2098 lwkt_reltoken(&p->p_token); 2099 continue; 2100 } 2101 2102 /* 2103 * If the traced bit got turned off, go back up 2104 * to the top to rescan signals. This ensures 2105 * that p_sig* and ps_sigact are consistent. 2106 */ 2107 if ((p->p_flags & P_TRACED) == 0) { 2108 /* haveptok is TRUE */ 2109 lwkt_reltoken(&p->p_token); 2110 continue; 2111 } 2112 } 2113 2114 /* 2115 * p_token may be held here 2116 */ 2117 prop = sigprop(sig); 2118 2119 /* 2120 * Decide whether the signal should be returned. 2121 * Return the signal's number, or fall through 2122 * to clear it from the pending mask. 2123 */ 2124 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2125 case (intptr_t)SIG_DFL: 2126 /* 2127 * Don't take default actions on system processes. 2128 */ 2129 if (p->p_pid <= 1) { 2130 #ifdef DIAGNOSTIC 2131 /* 2132 * Are you sure you want to ignore SIGSEGV 2133 * in init? XXX 2134 */ 2135 kprintf("Process (pid %lu) got signal %d\n", 2136 (u_long)p->p_pid, sig); 2137 #endif 2138 break; /* == ignore */ 2139 } 2140 2141 /* 2142 * Handle the in-kernel checkpoint action 2143 */ 2144 if (prop & SA_CKPT) { 2145 if (haveptok == 0) { 2146 lwkt_gettoken(&p->p_token); 2147 haveptok = 1; 2148 } 2149 checkpoint_signal_handler(lp); 2150 break; 2151 } 2152 2153 /* 2154 * If there is a pending stop signal to process 2155 * with default action, stop here, 2156 * then clear the signal. However, 2157 * if process is member of an orphaned 2158 * process group, ignore tty stop signals. 2159 */ 2160 if (prop & SA_STOP) { 2161 if (haveptok == 0) { 2162 lwkt_gettoken(&p->p_token); 2163 haveptok = 1; 2164 } 2165 if (p->p_flags & P_TRACED || 2166 (p->p_pgrp->pg_jobc == 0 && 2167 prop & SA_TTYSTOP)) 2168 break; /* == ignore */ 2169 if ((p->p_flags & P_WEXIT) == 0) { 2170 /* 2171 * NOTE: We do not block here. Issue 2172 * stopthe stop so other parties 2173 * see that we know we need to 2174 * stop. Locks might be held. 2175 */ 2176 p->p_xstat = sig; 2177 proc_stop(p, SSTOP); 2178 2179 #if 0 2180 tstop(); 2181 #endif 2182 } 2183 break; 2184 } else if (prop & SA_IGNORE) { 2185 /* 2186 * Except for SIGCONT, shouldn't get here. 2187 * Default action is to ignore; drop it. 2188 */ 2189 break; /* == ignore */ 2190 } else { 2191 if (ptokp) 2192 *ptokp = haveptok; 2193 else if (haveptok) 2194 lwkt_reltoken(&p->p_token); 2195 return (sig); 2196 } 2197 2198 /*NOTREACHED*/ 2199 2200 case (intptr_t)SIG_IGN: 2201 /* 2202 * Masking above should prevent us ever trying 2203 * to take action on an ignored signal other 2204 * than SIGCONT, unless process is traced. 2205 */ 2206 if ((prop & SA_CONT) == 0 && 2207 (p->p_flags & P_TRACED) == 0) 2208 kprintf("issignal\n"); 2209 break; /* == ignore */ 2210 2211 default: 2212 /* 2213 * This signal has an action, let 2214 * postsig() process it. 2215 */ 2216 if (ptokp) 2217 *ptokp = haveptok; 2218 else if (haveptok) 2219 lwkt_reltoken(&p->p_token); 2220 return (sig); 2221 } 2222 spin_lock(&lp->lwp_spin); 2223 lwp_delsig(lp, sig, haveptok); /* take the signal! */ 2224 spin_unlock(&lp->lwp_spin); 2225 2226 if (haveptok) 2227 lwkt_reltoken(&p->p_token); 2228 } 2229 /* NOTREACHED */ 2230 } 2231 2232 /* 2233 * Take the action for the specified signal from the current set of 2234 * pending signals. 2235 * 2236 * haveptok indicates whether the caller is holding p->p_token. If the 2237 * caller is, we are responsible for releasing it. 2238 * 2239 * This routine can only be called from the top-level trap from usermode. 2240 * It is expecting to be able to modify the top-level stack frame. 2241 */ 2242 void 2243 postsig(int sig, int haveptok) 2244 { 2245 struct lwp *lp = curthread->td_lwp; 2246 struct proc *p = lp->lwp_proc; 2247 struct sigacts *ps = p->p_sigacts; 2248 sig_t action; 2249 sigset_t returnmask; 2250 int code; 2251 2252 KASSERT(sig != 0, ("postsig")); 2253 2254 /* 2255 * If we are a virtual kernel running an emulated user process 2256 * context, switch back to the virtual kernel context before 2257 * trying to post the signal. 2258 */ 2259 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2260 struct trapframe *tf = lp->lwp_md.md_regs; 2261 tf->tf_trapno = 0; 2262 vkernel_trap(lp, tf); 2263 } 2264 2265 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2266 2267 spin_lock(&lp->lwp_spin); 2268 lwp_delsig(lp, sig, haveptok); 2269 spin_unlock(&lp->lwp_spin); 2270 action = ps->ps_sigact[_SIG_IDX(sig)]; 2271 #ifdef KTRACE 2272 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2273 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2274 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2275 #endif 2276 /* 2277 * We don't need p_token after this point. 2278 */ 2279 if (haveptok) 2280 lwkt_reltoken(&p->p_token); 2281 2282 STOPEVENT(p, S_SIG, sig); 2283 2284 if (action == SIG_DFL) { 2285 /* 2286 * Default action, where the default is to kill 2287 * the process. (Other cases were ignored above.) 2288 */ 2289 sigexit(lp, sig); 2290 /* NOTREACHED */ 2291 } else { 2292 /* 2293 * If we get here, the signal must be caught. 2294 */ 2295 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2296 ("postsig action")); 2297 2298 /* 2299 * Reset the signal handler if asked to 2300 */ 2301 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2302 /* 2303 * See kern_sigaction() for origin of this code. 2304 */ 2305 SIGDELSET(p->p_sigcatch, sig); 2306 if (sig != SIGCONT && 2307 sigprop(sig) & SA_IGNORE) 2308 SIGADDSET(p->p_sigignore, sig); 2309 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2310 } 2311 2312 /* 2313 * Set the signal mask and calculate the mask to restore 2314 * when the signal function returns. 2315 * 2316 * Special case: user has done a sigsuspend. Here the 2317 * current mask is not of interest, but rather the 2318 * mask from before the sigsuspend is what we want 2319 * restored after the signal processing is completed. 2320 */ 2321 if (lp->lwp_flags & LWP_OLDMASK) { 2322 returnmask = lp->lwp_oldsigmask; 2323 lp->lwp_flags &= ~LWP_OLDMASK; 2324 } else { 2325 returnmask = lp->lwp_sigmask; 2326 } 2327 2328 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2329 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2330 SIGADDSET(lp->lwp_sigmask, sig); 2331 2332 lp->lwp_ru.ru_nsignals++; 2333 if (lp->lwp_sig != sig) { 2334 code = 0; 2335 } else { 2336 code = lp->lwp_code; 2337 lp->lwp_code = 0; 2338 lp->lwp_sig = 0; 2339 } 2340 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2341 } 2342 } 2343 2344 /* 2345 * Kill the current process for stated reason. 2346 */ 2347 void 2348 killproc(struct proc *p, char *why) 2349 { 2350 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2351 p->p_pid, p->p_comm, 2352 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2353 ksignal(p, SIGKILL); 2354 } 2355 2356 /* 2357 * Force the current process to exit with the specified signal, dumping core 2358 * if appropriate. We bypass the normal tests for masked and caught signals, 2359 * allowing unrecoverable failures to terminate the process without changing 2360 * signal state. Mark the accounting record with the signal termination. 2361 * If dumping core, save the signal number for the debugger. Calls exit and 2362 * does not return. 2363 * 2364 * This routine does not return. 2365 */ 2366 void 2367 sigexit(struct lwp *lp, int sig) 2368 { 2369 struct proc *p = lp->lwp_proc; 2370 2371 lwkt_gettoken(&p->p_token); 2372 p->p_acflag |= AXSIG; 2373 if (sigprop(sig) & SA_CORE) { 2374 lp->lwp_sig = sig; 2375 2376 /* 2377 * All threads must be stopped before we can safely coredump. 2378 * Stop threads using SCORE, which cannot be overridden. 2379 */ 2380 if (p->p_stat != SCORE) { 2381 proc_stop(p, SCORE); 2382 proc_stopwait(p); 2383 2384 if (coredump(lp, sig) == 0) 2385 sig |= WCOREFLAG; 2386 p->p_stat = SSTOP; 2387 } 2388 2389 /* 2390 * Log signals which would cause core dumps 2391 * (Log as LOG_INFO to appease those who don't want 2392 * these messages.) 2393 * XXX : Todo, as well as euid, write out ruid too 2394 */ 2395 if (kern_logsigexit) { 2396 log(LOG_INFO, 2397 "pid %d (%s), uid %d: exited on signal %d%s\n", 2398 p->p_pid, p->p_comm, 2399 p->p_ucred ? p->p_ucred->cr_uid : -1, 2400 sig &~ WCOREFLAG, 2401 sig & WCOREFLAG ? " (core dumped)" : ""); 2402 if (kern_logsigexit > 1) 2403 kprintf("DEBUG - waiting on kern.logsigexit\n"); 2404 while (kern_logsigexit > 1) { 2405 tsleep(&kern_logsigexit, 0, "DEBUG", hz); 2406 } 2407 } 2408 } 2409 lwkt_reltoken(&p->p_token); 2410 exit1(W_EXITCODE(0, sig)); 2411 /* NOTREACHED */ 2412 } 2413 2414 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2415 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2416 sizeof(corefilename), "process corefile name format string"); 2417 2418 /* 2419 * expand_name(name, uid, pid) 2420 * Expand the name described in corefilename, using name, uid, and pid. 2421 * corefilename is a kprintf-like string, with three format specifiers: 2422 * %N name of process ("name") 2423 * %P process id (pid) 2424 * %U user id (uid) 2425 * For example, "%N.core" is the default; they can be disabled completely 2426 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2427 * This is controlled by the sysctl variable kern.corefile (see above). 2428 */ 2429 2430 static char * 2431 expand_name(const char *name, uid_t uid, pid_t pid) 2432 { 2433 char *temp; 2434 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2435 int i, n; 2436 char *format = corefilename; 2437 size_t namelen; 2438 2439 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2440 if (temp == NULL) 2441 return NULL; 2442 namelen = strlen(name); 2443 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2444 int l; 2445 switch (format[i]) { 2446 case '%': /* Format character */ 2447 i++; 2448 switch (format[i]) { 2449 case '%': 2450 temp[n++] = '%'; 2451 break; 2452 case 'N': /* process name */ 2453 if ((n + namelen) > MAXPATHLEN) { 2454 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2455 pid, name, uid, temp, name); 2456 kfree(temp, M_TEMP); 2457 return NULL; 2458 } 2459 memcpy(temp+n, name, namelen); 2460 n += namelen; 2461 break; 2462 case 'P': /* process id */ 2463 l = ksprintf(buf, "%u", pid); 2464 if ((n + l) > MAXPATHLEN) { 2465 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2466 pid, name, uid, temp, name); 2467 kfree(temp, M_TEMP); 2468 return NULL; 2469 } 2470 memcpy(temp+n, buf, l); 2471 n += l; 2472 break; 2473 case 'U': /* user id */ 2474 l = ksprintf(buf, "%u", uid); 2475 if ((n + l) > MAXPATHLEN) { 2476 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2477 pid, name, uid, temp, name); 2478 kfree(temp, M_TEMP); 2479 return NULL; 2480 } 2481 memcpy(temp+n, buf, l); 2482 n += l; 2483 break; 2484 default: 2485 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2486 } 2487 break; 2488 default: 2489 temp[n++] = format[i]; 2490 } 2491 } 2492 temp[n] = '\0'; 2493 return temp; 2494 } 2495 2496 /* 2497 * Dump a process' core. The main routine does some 2498 * policy checking, and creates the name of the coredump; 2499 * then it passes on a vnode and a size limit to the process-specific 2500 * coredump routine if there is one; if there _is not_ one, it returns 2501 * ENOSYS; otherwise it returns the error from the process-specific routine. 2502 * 2503 * The parameter `lp' is the lwp which triggered the coredump. 2504 */ 2505 2506 static int 2507 coredump(struct lwp *lp, int sig) 2508 { 2509 struct proc *p = lp->lwp_proc; 2510 struct vnode *vp; 2511 struct ucred *cred = p->p_ucred; 2512 struct flock lf; 2513 struct nlookupdata nd; 2514 struct vattr vattr; 2515 int error, error1; 2516 char *name; /* name of corefile */ 2517 off_t limit; 2518 2519 STOPEVENT(p, S_CORE, 0); 2520 2521 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2522 return (EFAULT); 2523 2524 /* 2525 * Note that the bulk of limit checking is done after 2526 * the corefile is created. The exception is if the limit 2527 * for corefiles is 0, in which case we don't bother 2528 * creating the corefile at all. This layout means that 2529 * a corefile is truncated instead of not being created, 2530 * if it is larger than the limit. 2531 */ 2532 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2533 if (limit == 0) 2534 return EFBIG; 2535 2536 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2537 if (name == NULL) 2538 return (EINVAL); 2539 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2540 if (error == 0) 2541 error = vn_open(&nd, NULL, 2542 O_CREAT | FWRITE | O_NOFOLLOW, 2543 S_IRUSR | S_IWUSR); 2544 kfree(name, M_TEMP); 2545 if (error) { 2546 nlookup_done(&nd); 2547 return (error); 2548 } 2549 vp = nd.nl_open_vp; 2550 nd.nl_open_vp = NULL; 2551 nlookup_done(&nd); 2552 2553 vn_unlock(vp); 2554 lf.l_whence = SEEK_SET; 2555 lf.l_start = 0; 2556 lf.l_len = 0; 2557 lf.l_type = F_WRLCK; 2558 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2559 if (error) 2560 goto out2; 2561 2562 /* Don't dump to non-regular files or files with links. */ 2563 if (vp->v_type != VREG || 2564 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2565 error = EFAULT; 2566 goto out1; 2567 } 2568 2569 /* Don't dump to files current user does not own */ 2570 if (vattr.va_uid != p->p_ucred->cr_uid) { 2571 error = EFAULT; 2572 goto out1; 2573 } 2574 2575 VATTR_NULL(&vattr); 2576 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2577 vattr.va_size = 0; 2578 VOP_SETATTR(vp, &vattr, cred); 2579 p->p_acflag |= ACORE; 2580 vn_unlock(vp); 2581 2582 error = p->p_sysent->sv_coredump ? 2583 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2584 2585 out1: 2586 lf.l_type = F_UNLCK; 2587 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2588 out2: 2589 error1 = vn_close(vp, FWRITE, NULL); 2590 if (error == 0) 2591 error = error1; 2592 return (error); 2593 } 2594 2595 /* 2596 * Nonexistent system call-- signal process (may want to handle it). 2597 * Flag error in case process won't see signal immediately (blocked or ignored). 2598 * 2599 * MPALMOSTSAFE 2600 */ 2601 /* ARGSUSED */ 2602 int 2603 sys_nosys(struct sysmsg *sysmsg, const struct nosys_args *args) 2604 { 2605 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2606 return (EINVAL); 2607 } 2608 2609 /* 2610 * Send a SIGIO or SIGURG signal to a process or process group using 2611 * stored credentials rather than those of the current process. 2612 */ 2613 void 2614 pgsigio(struct sigio *sigio, int sig, int checkctty) 2615 { 2616 if (sigio == NULL) 2617 return; 2618 2619 if (sigio->sio_pgid > 0) { 2620 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2621 sigio->sio_proc)) 2622 ksignal(sigio->sio_proc, sig); 2623 } else if (sigio->sio_pgid < 0) { 2624 struct proc *p; 2625 struct pgrp *pg = sigio->sio_pgrp; 2626 2627 /* 2628 * Must interlock all signals against fork 2629 */ 2630 pgref(pg); 2631 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2632 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2633 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2634 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2635 ksignal(p, sig); 2636 } 2637 lockmgr(&pg->pg_lock, LK_RELEASE); 2638 pgrel(pg); 2639 } 2640 } 2641 2642 static int 2643 filt_sigattach(struct knote *kn) 2644 { 2645 struct proc *p = curproc; 2646 2647 kn->kn_ptr.p_proc = p; 2648 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2649 2650 /* XXX lock the proc here while adding to the list? */ 2651 knote_insert(&p->p_klist, kn); 2652 2653 return (0); 2654 } 2655 2656 static void 2657 filt_sigdetach(struct knote *kn) 2658 { 2659 struct proc *p = kn->kn_ptr.p_proc; 2660 2661 knote_remove(&p->p_klist, kn); 2662 } 2663 2664 /* 2665 * signal knotes are shared with proc knotes, so we apply a mask to 2666 * the hint in order to differentiate them from process hints. This 2667 * could be avoided by using a signal-specific knote list, but probably 2668 * isn't worth the trouble. 2669 */ 2670 static int 2671 filt_signal(struct knote *kn, long hint) 2672 { 2673 if (hint & NOTE_SIGNAL) { 2674 hint &= ~NOTE_SIGNAL; 2675 2676 if (kn->kn_id == hint) 2677 kn->kn_data++; 2678 } 2679 return (kn->kn_data != 0); 2680 } 2681