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 __read_mostly sigset_t sigcantmask_mask; 207 208 static __inline int 209 sigprop(int sig) 210 { 211 212 if (sig > 0 && sig < NSIG) 213 return (sigproptbl[_SIG_IDX(sig)]); 214 215 return (0); 216 } 217 218 static __inline int 219 sig_ffs(sigset_t *set) 220 { 221 int i; 222 223 for (i = 0; i < _SIG_WORDS; i++) 224 if (set->__bits[i]) 225 return (ffs(set->__bits[i]) + (i * 32)); 226 return (0); 227 } 228 229 /* 230 * Allows us to populate siginfo->si_pid and si_uid in the target process 231 * (p) from the originating thread (td). This function must work properly 232 * even if a kernel thread is sending the signal. 233 * 234 * NOTE: Signals are not queued, so if multiple signals are received the 235 * signal handler will only see the most recent pid and uid for any 236 * given signal number. 237 */ 238 static __inline void 239 sigsetfrompid(thread_t td, struct proc *p, int sig) 240 { 241 struct sigacts *sap; 242 243 if ((sap = p->p_sigacts) == NULL) 244 return; 245 if (td->td_proc) { 246 sap->ps_frominfo[sig].pid = td->td_proc->p_pid; 247 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid; 248 } else { 249 sap->ps_frominfo[sig].pid = 0; 250 sap->ps_frominfo[sig].uid = 0; 251 } 252 } 253 254 /* 255 * No requirements. 256 */ 257 int 258 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) 259 { 260 struct thread *td = curthread; 261 struct proc *p = td->td_proc; 262 struct lwp *lp; 263 struct sigacts *ps = p->p_sigacts; 264 265 if (sig <= 0 || sig >= _SIG_MAXSIG) 266 return (EINVAL); 267 268 lwkt_gettoken(&p->p_token); 269 270 if (oact) { 271 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; 272 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; 273 oact->sa_flags = 0; 274 if (SIGISMEMBER(ps->ps_sigonstack, sig)) 275 oact->sa_flags |= SA_ONSTACK; 276 if (!SIGISMEMBER(ps->ps_sigintr, sig)) 277 oact->sa_flags |= SA_RESTART; 278 if (SIGISMEMBER(ps->ps_sigreset, sig)) 279 oact->sa_flags |= SA_RESETHAND; 280 if (SIGISMEMBER(ps->ps_signodefer, sig)) 281 oact->sa_flags |= SA_NODEFER; 282 if (SIGISMEMBER(ps->ps_siginfo, sig)) 283 oact->sa_flags |= SA_SIGINFO; 284 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) 285 oact->sa_flags |= SA_NOCLDSTOP; 286 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) 287 oact->sa_flags |= SA_NOCLDWAIT; 288 } 289 if (act) { 290 /* 291 * Check for invalid requests. KILL and STOP cannot be 292 * caught. 293 */ 294 if (sig == SIGKILL || sig == SIGSTOP) { 295 if (act->sa_handler != SIG_DFL) { 296 lwkt_reltoken(&p->p_token); 297 return (EINVAL); 298 } 299 } 300 301 /* 302 * Change setting atomically. 303 */ 304 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; 305 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); 306 if (act->sa_flags & SA_SIGINFO) { 307 ps->ps_sigact[_SIG_IDX(sig)] = 308 (__sighandler_t *)act->sa_sigaction; 309 SIGADDSET(ps->ps_siginfo, sig); 310 } else { 311 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; 312 SIGDELSET(ps->ps_siginfo, sig); 313 } 314 if (!(act->sa_flags & SA_RESTART)) 315 SIGADDSET(ps->ps_sigintr, sig); 316 else 317 SIGDELSET(ps->ps_sigintr, sig); 318 if (act->sa_flags & SA_ONSTACK) 319 SIGADDSET(ps->ps_sigonstack, sig); 320 else 321 SIGDELSET(ps->ps_sigonstack, sig); 322 if (act->sa_flags & SA_RESETHAND) 323 SIGADDSET(ps->ps_sigreset, sig); 324 else 325 SIGDELSET(ps->ps_sigreset, sig); 326 if (act->sa_flags & SA_NODEFER) 327 SIGADDSET(ps->ps_signodefer, sig); 328 else 329 SIGDELSET(ps->ps_signodefer, sig); 330 if (sig == SIGCHLD) { 331 if (act->sa_flags & SA_NOCLDSTOP) 332 p->p_sigacts->ps_flag |= PS_NOCLDSTOP; 333 else 334 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP; 335 if (act->sa_flags & SA_NOCLDWAIT) { 336 /* 337 * Paranoia: since SA_NOCLDWAIT is implemented 338 * by reparenting the dying child to PID 1 (and 339 * trust it to reap the zombie), PID 1 itself 340 * is forbidden to set SA_NOCLDWAIT. 341 */ 342 if (p->p_pid == 1) 343 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 344 else 345 p->p_sigacts->ps_flag |= PS_NOCLDWAIT; 346 } else { 347 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; 348 } 349 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 350 ps->ps_flag |= PS_CLDSIGIGN; 351 else 352 ps->ps_flag &= ~PS_CLDSIGIGN; 353 } 354 /* 355 * Set bit in p_sigignore for signals that are set to SIG_IGN, 356 * and for signals set to SIG_DFL where the default is to 357 * ignore. However, don't put SIGCONT in p_sigignore, as we 358 * have to restart the process. 359 * 360 * Also remove the signal from the process and lwp signal 361 * list. 362 */ 363 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || 364 (sigprop(sig) & SA_IGNORE && 365 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { 366 SIGDELSET_ATOMIC(p->p_siglist, sig); 367 FOREACH_LWP_IN_PROC(lp, p) { 368 spin_lock(&lp->lwp_spin); 369 SIGDELSET(lp->lwp_siglist, sig); 370 spin_unlock(&lp->lwp_spin); 371 } 372 if (sig != SIGCONT) { 373 /* easier in ksignal */ 374 SIGADDSET(p->p_sigignore, sig); 375 } 376 SIGDELSET(p->p_sigcatch, sig); 377 } else { 378 SIGDELSET(p->p_sigignore, sig); 379 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) 380 SIGDELSET(p->p_sigcatch, sig); 381 else 382 SIGADDSET(p->p_sigcatch, sig); 383 } 384 } 385 lwkt_reltoken(&p->p_token); 386 return (0); 387 } 388 389 int 390 sys_sigaction(struct sysmsg *sysmsg, const struct sigaction_args *uap) 391 { 392 struct sigaction act, oact; 393 struct sigaction *actp, *oactp; 394 int error; 395 396 actp = (uap->act != NULL) ? &act : NULL; 397 oactp = (uap->oact != NULL) ? &oact : NULL; 398 if (actp) { 399 error = copyin(uap->act, actp, sizeof(act)); 400 if (error) 401 return (error); 402 } 403 error = kern_sigaction(uap->sig, actp, oactp); 404 if (oactp && !error) { 405 error = copyout(oactp, uap->oact, sizeof(oact)); 406 } 407 return (error); 408 } 409 410 /* 411 * Initialize signal state for process 0; 412 * set to ignore signals that are ignored by default. 413 */ 414 void 415 siginit(struct proc *p) 416 { 417 int i; 418 419 for (i = 1; i <= NSIG; i++) { 420 if (sigprop(i) & SA_IGNORE && i != SIGCONT) 421 SIGADDSET(p->p_sigignore, i); 422 } 423 424 /* 425 * Also initialize signal-related global state. 426 */ 427 SIGSETOR_CANTMASK(sigcantmask_mask); 428 } 429 430 /* 431 * Reset signals for an exec of the specified process. 432 */ 433 void 434 execsigs(struct proc *p) 435 { 436 struct sigacts *ps = p->p_sigacts; 437 struct lwp *lp; 438 int sig; 439 440 lp = ONLY_LWP_IN_PROC(p); 441 442 /* 443 * Reset caught signals. Held signals remain held 444 * through p_sigmask (unless they were caught, 445 * and are now ignored by default). 446 */ 447 while (SIGNOTEMPTY(p->p_sigcatch)) { 448 sig = sig_ffs(&p->p_sigcatch); 449 SIGDELSET(p->p_sigcatch, sig); 450 if (sigprop(sig) & SA_IGNORE) { 451 if (sig != SIGCONT) 452 SIGADDSET(p->p_sigignore, sig); 453 SIGDELSET_ATOMIC(p->p_siglist, sig); 454 /* don't need spinlock */ 455 SIGDELSET(lp->lwp_siglist, sig); 456 } 457 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 458 } 459 460 /* 461 * Reset stack state to the user stack. 462 * Clear set of signals caught on the signal stack. 463 */ 464 lp->lwp_sigstk.ss_flags = SS_DISABLE; 465 lp->lwp_sigstk.ss_size = 0; 466 lp->lwp_sigstk.ss_sp = NULL; 467 lp->lwp_flags &= ~LWP_ALTSTACK; 468 /* 469 * Reset no zombies if child dies flag as Solaris does. 470 */ 471 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); 472 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) 473 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; 474 } 475 476 /* 477 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc 478 * 479 * Manipulate signal mask. This routine is MP SAFE *ONLY* if 480 * p == curproc. 481 */ 482 int 483 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) 484 { 485 struct thread *td = curthread; 486 struct lwp *lp = td->td_lwp; 487 struct proc *p = td->td_proc; 488 int error; 489 490 lwkt_gettoken(&p->p_token); 491 492 if (oset != NULL) 493 *oset = lp->lwp_sigmask; 494 495 error = 0; 496 if (set != NULL) { 497 switch (how) { 498 case SIG_BLOCK: 499 SIG_CANTMASK(*set); 500 SIGSETOR(lp->lwp_sigmask, *set); 501 break; 502 case SIG_UNBLOCK: 503 SIGSETNAND(lp->lwp_sigmask, *set); 504 break; 505 case SIG_SETMASK: 506 SIG_CANTMASK(*set); 507 lp->lwp_sigmask = *set; 508 break; 509 default: 510 error = EINVAL; 511 break; 512 } 513 } 514 515 lwkt_reltoken(&p->p_token); 516 517 return (error); 518 } 519 520 /* 521 * sigprocmask() 522 * 523 * MPSAFE 524 */ 525 int 526 sys_sigprocmask(struct sysmsg *sysmsg, const struct sigprocmask_args *uap) 527 { 528 sigset_t set, oset; 529 sigset_t *setp, *osetp; 530 int error; 531 532 setp = (uap->set != NULL) ? &set : NULL; 533 osetp = (uap->oset != NULL) ? &oset : NULL; 534 if (setp) { 535 error = copyin(uap->set, setp, sizeof(set)); 536 if (error) 537 return (error); 538 } 539 error = kern_sigprocmask(uap->how, setp, osetp); 540 if (osetp && !error) { 541 error = copyout(osetp, uap->oset, sizeof(oset)); 542 } 543 return (error); 544 } 545 546 /* 547 * MPSAFE 548 */ 549 int 550 kern_sigpending(sigset_t *set) 551 { 552 struct lwp *lp = curthread->td_lwp; 553 554 *set = lwp_sigpend(lp); 555 556 return (0); 557 } 558 559 /* 560 * MPSAFE 561 */ 562 int 563 sys_sigpending(struct sysmsg *sysmsg, const struct sigpending_args *uap) 564 { 565 sigset_t set; 566 int error; 567 568 error = kern_sigpending(&set); 569 570 if (error == 0) 571 error = copyout(&set, uap->set, sizeof(set)); 572 return (error); 573 } 574 575 /* 576 * Suspend process until signal, providing mask to be set 577 * in the meantime. 578 * 579 * MPSAFE 580 */ 581 int 582 kern_sigsuspend(sigset_t *set) 583 { 584 struct thread *td = curthread; 585 struct lwp *lp = td->td_lwp; 586 struct proc *p = td->td_proc; 587 struct sigacts *ps = p->p_sigacts; 588 589 /* 590 * When returning from sigsuspend, we want 591 * the old mask to be restored after the 592 * signal handler has finished. Thus, we 593 * save it here and mark the sigacts structure 594 * to indicate this. 595 */ 596 lp->lwp_oldsigmask = lp->lwp_sigmask; 597 lp->lwp_flags |= LWP_OLDMASK; 598 599 SIG_CANTMASK(*set); 600 lp->lwp_sigmask = *set; 601 while (tsleep(ps, PCATCH, "pause", 0) == 0) 602 /* void */; 603 /* always return EINTR rather than ERESTART... */ 604 return (EINTR); 605 } 606 607 /* 608 * Note nonstandard calling convention: libc stub passes mask, not 609 * pointer, to save a copyin. 610 * 611 * MPSAFE 612 */ 613 int 614 sys_sigsuspend(struct sysmsg *sysmsg, const struct sigsuspend_args *uap) 615 { 616 sigset_t mask; 617 int error; 618 619 error = copyin(uap->sigmask, &mask, sizeof(mask)); 620 if (error) 621 return (error); 622 623 error = kern_sigsuspend(&mask); 624 625 return (error); 626 } 627 628 /* 629 * MPSAFE 630 */ 631 int 632 kern_sigaltstack(stack_t *ss, stack_t *oss) 633 { 634 struct thread *td = curthread; 635 struct lwp *lp = td->td_lwp; 636 struct proc *p = td->td_proc; 637 638 if ((lp->lwp_flags & LWP_ALTSTACK) == 0) 639 lp->lwp_sigstk.ss_flags |= SS_DISABLE; 640 641 if (oss) 642 *oss = lp->lwp_sigstk; 643 644 if (ss) { 645 if (ss->ss_flags & ~SS_DISABLE) 646 return (EINVAL); 647 if (ss->ss_flags & SS_DISABLE) { 648 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) 649 return (EPERM); 650 lp->lwp_flags &= ~LWP_ALTSTACK; 651 lp->lwp_sigstk.ss_flags = ss->ss_flags; 652 } else { 653 if (ss->ss_size < p->p_sysent->sv_minsigstksz) 654 return (ENOMEM); 655 lp->lwp_flags |= LWP_ALTSTACK; 656 lp->lwp_sigstk = *ss; 657 } 658 } 659 660 return (0); 661 } 662 663 /* 664 * MPSAFE 665 */ 666 int 667 sys_sigaltstack(struct sysmsg *sysmsg, const struct sigaltstack_args *uap) 668 { 669 stack_t ss, oss; 670 int error; 671 672 if (uap->ss) { 673 error = copyin(uap->ss, &ss, sizeof(ss)); 674 if (error) 675 return (error); 676 } 677 678 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); 679 680 if (error == 0 && uap->oss) 681 error = copyout(&oss, uap->oss, sizeof(*uap->oss)); 682 return (error); 683 } 684 685 /* 686 * Common code for kill process group/broadcast kill. 687 * cp is calling process. 688 */ 689 struct killpg_info { 690 int nfound; 691 int sig; 692 }; 693 694 static int killpg_all_callback(struct proc *p, void *data); 695 696 static int 697 dokillpg(int sig, int pgid, int all) 698 { 699 struct killpg_info info; 700 struct proc *cp = curproc; 701 struct proc *p; 702 struct pgrp *pgrp; 703 704 info.nfound = 0; 705 info.sig = sig; 706 707 if (all) { 708 /* 709 * broadcast 710 */ 711 allproc_scan(killpg_all_callback, &info, 0); 712 } else { 713 if (pgid == 0) { 714 /* 715 * zero pgid means send to my process group. 716 */ 717 pgrp = cp->p_pgrp; 718 pgref(pgrp); 719 } else { 720 pgrp = pgfind(pgid); 721 if (pgrp == NULL) 722 return (ESRCH); 723 } 724 725 /* 726 * Must interlock all signals against fork 727 */ 728 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 729 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 730 if (p->p_pid <= 1 || 731 p->p_stat == SZOMB || 732 (p->p_flags & P_SYSTEM) || 733 !CANSIGNAL(p, sig, 0)) { 734 continue; 735 } 736 ++info.nfound; 737 if (sig) 738 ksignal(p, sig); 739 } 740 lockmgr(&pgrp->pg_lock, LK_RELEASE); 741 pgrel(pgrp); 742 } 743 return (info.nfound ? 0 : ESRCH); 744 } 745 746 static int 747 killpg_all_callback(struct proc *p, void *data) 748 { 749 struct killpg_info *info = data; 750 751 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || 752 p == curproc || !CANSIGNAL(p, info->sig, 0)) { 753 return (0); 754 } 755 ++info->nfound; 756 if (info->sig) 757 ksignal(p, info->sig); 758 return(0); 759 } 760 761 /* 762 * Send a general signal to a process or LWPs within that process. 763 * 764 * Note that new signals cannot be sent if a process is exiting or already 765 * a zombie, but we return success anyway as userland is likely to not handle 766 * the race properly. 767 * 768 * No requirements. 769 */ 770 int 771 kern_kill(int sig, pid_t pid, lwpid_t tid) 772 { 773 int t; 774 775 if ((u_int)sig >= _SIG_MAXSIG) 776 return (EINVAL); 777 778 if (pid > 0) { 779 struct proc *p; 780 struct lwp *lp = NULL; 781 782 /* 783 * Send a signal to a single process. If the kill() is 784 * racing an exiting process which has not yet been reaped 785 * act as though the signal was delivered successfully but 786 * don't actually try to deliver the signal. 787 */ 788 if ((p = pfind(pid)) == NULL) { 789 if ((p = zpfind(pid)) == NULL) 790 return (ESRCH); 791 PRELE(p); 792 return (0); 793 } 794 if (p != curproc) { 795 lwkt_gettoken_shared(&p->p_token); 796 if (!CANSIGNAL(p, sig, 1)) { 797 lwkt_reltoken(&p->p_token); 798 PRELE(p); 799 return (EPERM); 800 } 801 lwkt_reltoken(&p->p_token); 802 } 803 804 /* 805 * NOP if the process is exiting. Note that lwpsignal() is 806 * called directly with P_WEXIT set to kill individual LWPs 807 * during exit, which is allowed. 808 */ 809 if (p->p_flags & P_WEXIT) { 810 PRELE(p); 811 return (0); 812 } 813 if (tid != -1) { 814 lwkt_gettoken_shared(&p->p_token); 815 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); 816 if (lp == NULL) { 817 lwkt_reltoken(&p->p_token); 818 PRELE(p); 819 return (ESRCH); 820 } 821 LWPHOLD(lp); 822 lwkt_reltoken(&p->p_token); 823 } 824 if (sig) 825 lwpsignal(p, lp, sig); 826 if (lp) 827 LWPRELE(lp); 828 PRELE(p); 829 830 return (0); 831 } 832 833 /* 834 * If we come here, pid is a special broadcast pid. 835 * This doesn't mix with a tid. 836 */ 837 if (tid != -1) 838 return (EINVAL); 839 840 switch (pid) { 841 case -1: /* broadcast signal */ 842 t = (dokillpg(sig, 0, 1)); 843 break; 844 case 0: /* signal own process group */ 845 t = (dokillpg(sig, 0, 0)); 846 break; 847 default: /* negative explicit process group */ 848 t = (dokillpg(sig, -pid, 0)); 849 break; 850 } 851 return t; 852 } 853 854 int 855 sys_kill(struct sysmsg *sysmsg, const struct kill_args *uap) 856 { 857 int error; 858 859 error = kern_kill(uap->signum, uap->pid, -1); 860 return (error); 861 } 862 863 int 864 sys_lwp_kill(struct sysmsg *sysmsg, const struct lwp_kill_args *uap) 865 { 866 int error; 867 pid_t pid = uap->pid; 868 869 /* 870 * A tid is mandatory for lwp_kill(), otherwise 871 * you could simply use kill(). 872 */ 873 if (uap->tid == -1) 874 return (EINVAL); 875 876 /* 877 * To save on a getpid() function call for intra-process 878 * signals, pid == -1 means current process. 879 */ 880 if (pid == -1) 881 pid = curproc->p_pid; 882 883 error = kern_kill(uap->signum, pid, uap->tid); 884 return (error); 885 } 886 887 /* 888 * Send a signal to a process group. 889 */ 890 void 891 gsignal(int pgid, int sig) 892 { 893 struct pgrp *pgrp; 894 895 if (pgid && (pgrp = pgfind(pgid))) 896 pgsignal(pgrp, sig, 0); 897 } 898 899 /* 900 * Send a signal to a process group. If checktty is 1, 901 * limit to members which have a controlling terminal. 902 * 903 * pg_lock interlocks against a fork that might be in progress, to 904 * ensure that the new child process picks up the signal. 905 */ 906 void 907 pgsignal(struct pgrp *pgrp, int sig, int checkctty) 908 { 909 struct proc *p; 910 911 /* 912 * Must interlock all signals against fork 913 */ 914 if (pgrp) { 915 pgref(pgrp); 916 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); 917 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { 918 if (checkctty == 0 || p->p_flags & P_CONTROLT) 919 ksignal(p, sig); 920 } 921 lockmgr(&pgrp->pg_lock, LK_RELEASE); 922 pgrel(pgrp); 923 } 924 } 925 926 /* 927 * Send a signal caused by a trap to the current lwp. If it will be caught 928 * immediately, deliver it with correct code. Otherwise, post it normally. 929 * 930 * These signals may ONLY be delivered to the specified lwp and may never 931 * be delivered to the process generically. 932 * 933 * lpmap->blockallsigs is ignored. 934 */ 935 void 936 trapsignal(struct lwp *lp, int sig, u_long code) 937 { 938 struct proc *p = lp->lwp_proc; 939 struct sigacts *ps = p->p_sigacts; 940 941 /* 942 * If we are a virtual kernel running an emulated user process 943 * context, switch back to the virtual kernel context before 944 * trying to post the signal. 945 */ 946 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 947 struct trapframe *tf = lp->lwp_md.md_regs; 948 tf->tf_trapno = 0; 949 vkernel_trap(lp, tf); 950 } 951 952 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && 953 !SIGISMEMBER(lp->lwp_sigmask, sig)) { 954 lp->lwp_ru.ru_nsignals++; 955 #ifdef KTRACE 956 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 957 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], 958 &lp->lwp_sigmask, code); 959 #endif 960 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, 961 &lp->lwp_sigmask, code); 962 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 963 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 964 SIGADDSET(lp->lwp_sigmask, sig); 965 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 966 /* 967 * See kern_sigaction() for origin of this code. 968 */ 969 SIGDELSET(p->p_sigcatch, sig); 970 if (sig != SIGCONT && 971 sigprop(sig) & SA_IGNORE) 972 SIGADDSET(p->p_sigignore, sig); 973 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 974 } 975 } else { 976 lp->lwp_code = code; /* XXX for core dump/debugger */ 977 lp->lwp_sig = sig; /* XXX to verify code */ 978 lwpsignal(p, lp, sig); 979 } 980 } 981 982 /* 983 * Find a suitable lwp to deliver the signal to. Returns NULL if all 984 * lwps hold the signal blocked. 985 * 986 * Caller must hold p->p_token. 987 * 988 * Returns a lp or NULL. If non-NULL the lp is held and its token is 989 * acquired. 990 */ 991 static struct lwp * 992 find_lwp_for_signal(struct proc *p, int sig) 993 { 994 struct lwp *lp; 995 struct lwp *run, *sleep, *stop; 996 997 /* 998 * If the running/preempted thread belongs to the proc to which 999 * the signal is being delivered and this thread does not block 1000 * the signal, then we can avoid a context switch by delivering 1001 * the signal to this thread, because it will return to userland 1002 * soon anyways. 1003 */ 1004 lp = lwkt_preempted_proc(); 1005 if (lp != NULL && lp->lwp_proc == p) { 1006 LWPHOLD(lp); 1007 lwkt_gettoken(&lp->lwp_token); 1008 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { 1009 /* return w/ token held */ 1010 return (lp); 1011 } 1012 lwkt_reltoken(&lp->lwp_token); 1013 LWPRELE(lp); 1014 } 1015 1016 run = sleep = stop = NULL; 1017 FOREACH_LWP_IN_PROC(lp, p) { 1018 /* 1019 * If the signal is being blocked by the lwp, then this 1020 * lwp is not eligible for receiving the signal. 1021 */ 1022 LWPHOLD(lp); 1023 lwkt_gettoken(&lp->lwp_token); 1024 1025 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1026 lwkt_reltoken(&lp->lwp_token); 1027 LWPRELE(lp); 1028 continue; 1029 } 1030 1031 switch (lp->lwp_stat) { 1032 case LSRUN: 1033 if (sleep) { 1034 lwkt_token_swap(); 1035 lwkt_reltoken(&sleep->lwp_token); 1036 LWPRELE(sleep); 1037 sleep = NULL; 1038 run = lp; 1039 } else if (stop) { 1040 lwkt_token_swap(); 1041 lwkt_reltoken(&stop->lwp_token); 1042 LWPRELE(stop); 1043 stop = NULL; 1044 run = lp; 1045 } else { 1046 run = lp; 1047 } 1048 break; 1049 case LSSLEEP: 1050 if (lp->lwp_flags & LWP_SINTR) { 1051 if (sleep) { 1052 lwkt_reltoken(&lp->lwp_token); 1053 LWPRELE(lp); 1054 } else if (stop) { 1055 lwkt_token_swap(); 1056 lwkt_reltoken(&stop->lwp_token); 1057 LWPRELE(stop); 1058 stop = NULL; 1059 sleep = lp; 1060 } else { 1061 sleep = lp; 1062 } 1063 } else { 1064 lwkt_reltoken(&lp->lwp_token); 1065 LWPRELE(lp); 1066 } 1067 break; 1068 case LSSTOP: 1069 if (sleep) { 1070 lwkt_reltoken(&lp->lwp_token); 1071 LWPRELE(lp); 1072 } else if (stop) { 1073 lwkt_reltoken(&lp->lwp_token); 1074 LWPRELE(lp); 1075 } else { 1076 stop = lp; 1077 } 1078 break; 1079 } 1080 if (run) 1081 break; 1082 } 1083 1084 if (run != NULL) 1085 return (run); 1086 else if (sleep != NULL) 1087 return (sleep); 1088 else 1089 return (stop); 1090 } 1091 1092 /* 1093 * Send the signal to the process. If the signal has an action, the action 1094 * is usually performed by the target process rather than the caller; we add 1095 * the signal to the set of pending signals for the process. 1096 * 1097 * Exceptions: 1098 * o When a stop signal is sent to a sleeping process that takes the 1099 * default action, the process is stopped without awakening it. 1100 * o SIGCONT restarts stopped processes (or puts them back to sleep) 1101 * regardless of the signal action (eg, blocked or ignored). 1102 * 1103 * Other ignored signals are discarded immediately. 1104 * 1105 * If the caller wishes to call this function from a hard code section the 1106 * caller must already hold p->p_token (see kern_clock.c). 1107 * 1108 * No requirements. 1109 */ 1110 void 1111 ksignal(struct proc *p, int sig) 1112 { 1113 lwpsignal(p, NULL, sig); 1114 } 1115 1116 /* 1117 * The core for ksignal. lp may be NULL, then a suitable thread 1118 * will be chosen. If not, lp MUST be a member of p. 1119 * 1120 * If the caller wishes to call this function from a hard code section the 1121 * caller must already hold p->p_token. 1122 * 1123 * No requirements. 1124 */ 1125 void 1126 lwpsignal(struct proc *p, struct lwp *lp, int sig) 1127 { 1128 struct proc *q; 1129 sig_t action; 1130 int prop; 1131 1132 if (sig >= _SIG_MAXSIG || sig <= 0) { 1133 kprintf("lwpsignal: signal %d\n", sig); 1134 panic("lwpsignal signal number"); 1135 } 1136 1137 KKASSERT(lp == NULL || lp->lwp_proc == p); 1138 1139 /* 1140 * We don't want to race... well, all sorts of things. Get appropriate 1141 * tokens. 1142 * 1143 * Don't try to deliver a generic signal to an exiting process, 1144 * the signal structures could be in flux. We check the LWP later 1145 * on. 1146 */ 1147 PHOLD(p); 1148 if (lp) { 1149 LWPHOLD(lp); 1150 lwkt_gettoken(&lp->lwp_token); 1151 } else { 1152 lwkt_gettoken(&p->p_token); 1153 if (p->p_flags & P_WEXIT) 1154 goto out; 1155 } 1156 1157 prop = sigprop(sig); 1158 1159 /* 1160 * If proc is traced, always give parent a chance; 1161 * if signal event is tracked by procfs, give *that* 1162 * a chance, as well. 1163 */ 1164 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { 1165 action = SIG_DFL; 1166 } else { 1167 /* 1168 * Do not try to deliver signals to an exiting lwp other 1169 * than SIGKILL. Note that we must still deliver the signal 1170 * if P_WEXIT is set in the process flags. 1171 */ 1172 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { 1173 lwkt_reltoken(&lp->lwp_token); 1174 LWPRELE(lp); 1175 PRELE(p); 1176 return; 1177 } 1178 1179 /* 1180 * If the signal is being ignored, then we forget about 1181 * it immediately. NOTE: We don't set SIGCONT in p_sigignore, 1182 * and if it is set to SIG_IGN, action will be SIG_DFL here. 1183 */ 1184 if (SIGISMEMBER(p->p_sigignore, sig)) { 1185 /* 1186 * Even if a signal is set SIG_IGN, it may still be 1187 * lurking in a kqueue. 1188 */ 1189 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1190 if (lp) { 1191 lwkt_reltoken(&lp->lwp_token); 1192 LWPRELE(lp); 1193 } else { 1194 lwkt_reltoken(&p->p_token); 1195 } 1196 PRELE(p); 1197 return; 1198 } 1199 if (SIGISMEMBER(p->p_sigcatch, sig)) 1200 action = SIG_CATCH; 1201 else 1202 action = SIG_DFL; 1203 } 1204 1205 /* 1206 * If continuing, clear any pending STOP signals for the whole 1207 * process. 1208 */ 1209 if (prop & SA_CONT) { 1210 lwkt_gettoken(&p->p_token); 1211 SIG_STOPSIGMASK_ATOMIC(p->p_siglist); 1212 lwkt_reltoken(&p->p_token); 1213 } 1214 1215 if (prop & SA_STOP) { 1216 /* 1217 * If sending a tty stop signal to a member of an orphaned 1218 * process group, discard the signal here if the action 1219 * is default; don't stop the process below if sleeping, 1220 * and don't clear any pending SIGCONT. 1221 */ 1222 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && 1223 action == SIG_DFL) { 1224 if (lp) { 1225 lwkt_reltoken(&lp->lwp_token); 1226 LWPRELE(lp); 1227 } else { 1228 lwkt_reltoken(&p->p_token); 1229 } 1230 PRELE(p); 1231 return; 1232 } 1233 lwkt_gettoken(&p->p_token); 1234 SIG_CONTSIGMASK_ATOMIC(p->p_siglist); 1235 p->p_flags &= ~P_CONTINUED; 1236 lwkt_reltoken(&p->p_token); 1237 } 1238 1239 if (p->p_stat == SSTOP) { 1240 /* 1241 * Nobody can handle this signal, add it to the lwp or 1242 * process pending list 1243 */ 1244 lwkt_gettoken(&p->p_token); 1245 if (p->p_stat != SSTOP) { 1246 lwkt_reltoken(&p->p_token); 1247 goto not_stopped; 1248 } 1249 sigsetfrompid(curthread, p, sig); 1250 if (lp) { 1251 spin_lock(&lp->lwp_spin); 1252 SIGADDSET(lp->lwp_siglist, sig); 1253 spin_unlock(&lp->lwp_spin); 1254 } else { 1255 SIGADDSET_ATOMIC(p->p_siglist, sig); 1256 } 1257 1258 /* 1259 * If the process is stopped and is being traced, then no 1260 * further action is necessary. 1261 */ 1262 if (p->p_flags & P_TRACED) { 1263 lwkt_reltoken(&p->p_token); 1264 goto out; 1265 } 1266 1267 /* 1268 * If the process is stopped and receives a KILL signal, 1269 * make the process runnable. 1270 */ 1271 if (sig == SIGKILL) { 1272 proc_unstop(p, SSTOP); 1273 lwkt_reltoken(&p->p_token); 1274 goto active_process; 1275 } 1276 1277 /* 1278 * If the process is stopped and receives a CONT signal, 1279 * then try to make the process runnable again. 1280 */ 1281 if (prop & SA_CONT) { 1282 /* 1283 * If SIGCONT is default (or ignored), we continue the 1284 * process but don't leave the signal in p_siglist, as 1285 * it has no further action. If SIGCONT is held, we 1286 * continue the process and leave the signal in 1287 * p_siglist. If the process catches SIGCONT, let it 1288 * handle the signal itself. 1289 * 1290 * XXX what if the signal is being held blocked? 1291 * 1292 * Token required to interlock kern_wait(). 1293 * Reparenting can also cause a race so we have to 1294 * hold (q). 1295 */ 1296 q = p->p_pptr; 1297 PHOLD(q); 1298 lwkt_gettoken(&q->p_token); 1299 p->p_flags |= P_CONTINUED; 1300 wakeup(q); 1301 if (action == SIG_DFL) 1302 SIGDELSET_ATOMIC(p->p_siglist, sig); 1303 proc_unstop(p, SSTOP); 1304 lwkt_reltoken(&q->p_token); 1305 PRELE(q); 1306 lwkt_reltoken(&p->p_token); 1307 if (action == SIG_CATCH) 1308 goto active_process; 1309 goto out; 1310 } 1311 1312 /* 1313 * If the process is stopped and receives another STOP 1314 * signal, we do not need to stop it again. If we did 1315 * the shell could get confused. 1316 * 1317 * However, if the current/preempted lwp is part of the 1318 * process receiving the signal, we need to keep it, 1319 * so that this lwp can stop in issignal() later, as 1320 * we don't want to wait until it reaches userret! 1321 */ 1322 if (prop & SA_STOP) { 1323 if (lwkt_preempted_proc() == NULL || 1324 lwkt_preempted_proc()->lwp_proc != p) { 1325 SIGDELSET_ATOMIC(p->p_siglist, sig); 1326 } 1327 } 1328 1329 /* 1330 * Otherwise the process is stopped and it received some 1331 * signal, which does not change its stopped state. When 1332 * the process is continued a wakeup(p) will be issued which 1333 * will wakeup any threads sleeping in tstop(). 1334 */ 1335 lwkt_reltoken(&p->p_token); 1336 goto out; 1337 /* NOTREACHED */ 1338 } 1339 not_stopped: 1340 ; 1341 /* else not stopped */ 1342 active_process: 1343 1344 /* 1345 * Never deliver a lwp-specific signal to a random lwp. 1346 */ 1347 if (lp == NULL) { 1348 /* NOTE: returns lp w/ token held */ 1349 lp = find_lwp_for_signal(p, sig); 1350 if (lp) { 1351 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 1352 lwkt_reltoken(&lp->lwp_token); 1353 LWPRELE(lp); 1354 lp = NULL; 1355 /* maintain proc token */ 1356 } else { 1357 lwkt_token_swap(); 1358 lwkt_reltoken(&p->p_token); 1359 /* maintain lp token */ 1360 } 1361 } 1362 } 1363 1364 /* 1365 * Deliver to the process generically if (1) the signal is being 1366 * sent to any thread or (2) we could not find a thread to deliver 1367 * it to. 1368 */ 1369 if (lp == NULL) { 1370 sigsetfrompid(curthread, p, sig); 1371 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 1372 SIGADDSET_ATOMIC(p->p_siglist, sig); 1373 goto out; 1374 } 1375 1376 /* 1377 * Deliver to a specific LWP whether it masks it or not. It will 1378 * not be dispatched if masked but we must still deliver it. 1379 */ 1380 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && 1381 (p->p_flags & P_TRACED) == 0) { 1382 lwkt_gettoken(&p->p_token); 1383 p->p_nice = NZERO; 1384 lwkt_reltoken(&p->p_token); 1385 } 1386 1387 /* 1388 * If the process receives a STOP signal which indeed needs to 1389 * stop the process, do so. If the process chose to catch the 1390 * signal, it will be treated like any other signal. 1391 */ 1392 if ((prop & SA_STOP) && action == SIG_DFL) { 1393 /* 1394 * If a child holding parent blocked, stopping 1395 * could cause deadlock. Take no action at this 1396 * time. 1397 */ 1398 lwkt_gettoken(&p->p_token); 1399 if (p->p_flags & P_PPWAIT) { 1400 sigsetfrompid(curthread, p, sig); 1401 SIGADDSET_ATOMIC(p->p_siglist, sig); 1402 lwkt_reltoken(&p->p_token); 1403 goto out; 1404 } 1405 1406 /* 1407 * Do not actually try to manipulate the process, but simply 1408 * stop it. Lwps will stop as soon as they safely can. 1409 * 1410 * Ignore stop if the process is exiting. 1411 */ 1412 if ((p->p_flags & P_WEXIT) == 0) { 1413 p->p_xstat = sig; 1414 proc_stop(p, SSTOP); 1415 } 1416 lwkt_reltoken(&p->p_token); 1417 goto out; 1418 } 1419 1420 /* 1421 * If it is a CONT signal with default action, just ignore it. 1422 */ 1423 if ((prop & SA_CONT) && action == SIG_DFL) 1424 goto out; 1425 1426 /* 1427 * Mark signal pending at this specific thread. 1428 */ 1429 sigsetfrompid(curthread, p, sig); 1430 spin_lock(&lp->lwp_spin); 1431 SIGADDSET(lp->lwp_siglist, sig); 1432 spin_unlock(&lp->lwp_spin); 1433 1434 lwp_signotify(lp); 1435 1436 out: 1437 if (lp) { 1438 lwkt_reltoken(&lp->lwp_token); 1439 LWPRELE(lp); 1440 } else { 1441 lwkt_reltoken(&p->p_token); 1442 } 1443 PRELE(p); 1444 } 1445 1446 /* 1447 * Notify the LWP that a signal has arrived. The LWP does not have to be 1448 * sleeping on the current cpu. 1449 * 1450 * p->p_token and lp->lwp_token must be held on call. 1451 * 1452 * We can only safely schedule the thread on its current cpu and only if 1453 * one of the SINTR flags is set. If an SINTR flag is set AND we are on 1454 * the correct cpu we are properly interlocked, otherwise we could be 1455 * racing other thread transition states (or the lwp is on the user scheduler 1456 * runq but not scheduled) and must not do anything. 1457 * 1458 * Since we hold the lwp token we know the lwp cannot be ripped out from 1459 * under us so we can safely hold it to prevent it from being ripped out 1460 * from under us if we are forced to IPI another cpu to make the local 1461 * checks there. 1462 * 1463 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, 1464 * which we won't in an IPI so any fixups have to be done here, effectively 1465 * replicating part of what setrunnable() does. 1466 */ 1467 static void 1468 lwp_signotify(struct lwp *lp) 1469 { 1470 thread_t dtd; 1471 1472 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); 1473 dtd = lp->lwp_thread; 1474 1475 crit_enter(); 1476 if (lp == lwkt_preempted_proc()) { 1477 /* 1478 * lwp is on the current cpu AND it is currently running 1479 * (we preempted it). 1480 */ 1481 signotify(); 1482 } else if (lp->lwp_flags & LWP_SINTR) { 1483 /* 1484 * lwp is sitting in tsleep() with PCATCH set 1485 */ 1486 if (dtd->td_gd == mycpu) { 1487 setrunnable(lp); 1488 } else { 1489 /* 1490 * We can only adjust lwp_stat while we hold the 1491 * lwp_token, and we won't in the IPI function. 1492 */ 1493 LWPHOLD(lp); 1494 if (lp->lwp_stat == LSSTOP) 1495 lp->lwp_stat = LSSLEEP; 1496 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1497 } 1498 } else if (dtd->td_flags & TDF_SINTR) { 1499 /* 1500 * lwp is sitting in lwkt_sleep() with PCATCH set. 1501 */ 1502 if (dtd->td_gd == mycpu) { 1503 setrunnable(lp); 1504 } else { 1505 /* 1506 * We can only adjust lwp_stat while we hold the 1507 * lwp_token, and we won't in the IPI function. 1508 */ 1509 LWPHOLD(lp); 1510 if (lp->lwp_stat == LSSTOP) 1511 lp->lwp_stat = LSSLEEP; 1512 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1513 } 1514 } else { 1515 /* 1516 * Otherwise the lwp is either in some uninterruptible state 1517 * or it is on the userland scheduler's runqueue waiting to 1518 * be scheduled to a cpu, or it is running in userland. We 1519 * generally want to send an IPI so a running target gets the 1520 * signal ASAP, otherwise a scheduler-tick worth of latency 1521 * will occur. 1522 * 1523 * Issue an IPI to the remote cpu to knock it into the kernel, 1524 * remote cpu will issue the cpu-local signotify() if the IPI 1525 * preempts the desired thread. 1526 */ 1527 if (dtd->td_gd != mycpu) { 1528 LWPHOLD(lp); 1529 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); 1530 } 1531 } 1532 crit_exit(); 1533 } 1534 1535 /* 1536 * This function is called via an IPI so we cannot call setrunnable() here 1537 * (because while we hold the lp we don't own its token, and can't get it 1538 * from an IPI). 1539 * 1540 * We are interlocked by virtue of being on the same cpu as the target. If 1541 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule 1542 * the target thread. 1543 */ 1544 static void 1545 lwp_signotify_remote(void *arg) 1546 { 1547 struct lwp *lp = arg; 1548 thread_t td = lp->lwp_thread; 1549 1550 if (lp == lwkt_preempted_proc()) { 1551 signotify(); 1552 LWPRELE(lp); 1553 } else if (td->td_gd == mycpu) { 1554 if ((lp->lwp_flags & LWP_SINTR) || 1555 (td->td_flags & TDF_SINTR)) { 1556 lwkt_schedule(td); 1557 } 1558 LWPRELE(lp); 1559 } else { 1560 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); 1561 /* LWPHOLD() is forwarded to the target cpu */ 1562 } 1563 } 1564 1565 /* 1566 * Caller must hold p->p_token 1567 */ 1568 void 1569 proc_stop(struct proc *p, int stat) 1570 { 1571 struct proc *q; 1572 struct lwp *lp; 1573 1574 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1575 1576 /* 1577 * If somebody raced us, be happy with it. SCORE overrides SSTOP. 1578 */ 1579 if (stat == SCORE) { 1580 if (p->p_stat == SCORE || p->p_stat == SZOMB) 1581 return; 1582 } else { 1583 if (p->p_stat == SSTOP || p->p_stat == SCORE || 1584 p->p_stat == SZOMB) { 1585 return; 1586 } 1587 } 1588 p->p_stat = stat; 1589 1590 FOREACH_LWP_IN_PROC(lp, p) { 1591 LWPHOLD(lp); 1592 lwkt_gettoken(&lp->lwp_token); 1593 1594 switch (lp->lwp_stat) { 1595 case LSSTOP: 1596 /* 1597 * Do nothing, we are already counted in 1598 * p_nstopped. 1599 */ 1600 break; 1601 1602 case LSSLEEP: 1603 /* 1604 * We're sleeping, but we will stop before 1605 * returning to userspace, so count us 1606 * as stopped as well. We set LWP_MP_WSTOP 1607 * to signal the lwp that it should not 1608 * increase p_nstopped when reaching tstop(). 1609 * 1610 * LWP_MP_WSTOP is protected by lp->lwp_token. 1611 */ 1612 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { 1613 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); 1614 ++p->p_nstopped; 1615 } 1616 break; 1617 1618 case LSRUN: 1619 /* 1620 * We might notify ourself, but that's not 1621 * a problem. 1622 */ 1623 lwp_signotify(lp); 1624 break; 1625 } 1626 lwkt_reltoken(&lp->lwp_token); 1627 LWPRELE(lp); 1628 } 1629 1630 if (p->p_nstopped == p->p_nthreads) { 1631 /* 1632 * Token required to interlock kern_wait(). Reparenting can 1633 * also cause a race so we have to hold (q). 1634 */ 1635 q = p->p_pptr; 1636 PHOLD(q); 1637 lwkt_gettoken(&q->p_token); 1638 p->p_flags &= ~P_WAITED; 1639 wakeup(q); 1640 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) 1641 ksignal(p->p_pptr, SIGCHLD); 1642 lwkt_reltoken(&q->p_token); 1643 PRELE(q); 1644 } 1645 } 1646 1647 /* 1648 * Caller must hold p_token 1649 */ 1650 void 1651 proc_unstop(struct proc *p, int stat) 1652 { 1653 struct lwp *lp; 1654 1655 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 1656 1657 if (p->p_stat != stat) 1658 return; 1659 1660 p->p_stat = SACTIVE; 1661 1662 FOREACH_LWP_IN_PROC(lp, p) { 1663 LWPHOLD(lp); 1664 lwkt_gettoken(&lp->lwp_token); 1665 1666 switch (lp->lwp_stat) { 1667 case LSRUN: 1668 /* 1669 * Uh? Not stopped? Well, I guess that's okay. 1670 */ 1671 if (bootverbose) 1672 kprintf("proc_unstop: lwp %d/%d not sleeping\n", 1673 p->p_pid, lp->lwp_tid); 1674 break; 1675 1676 case LSSLEEP: 1677 /* 1678 * Still sleeping. Don't bother waking it up. 1679 * However, if this thread was counted as 1680 * stopped, undo this. 1681 * 1682 * Nevertheless we call setrunnable() so that it 1683 * will wake up in case a signal or timeout arrived 1684 * in the meantime. 1685 * 1686 * LWP_MP_WSTOP is protected by lp->lwp_token. 1687 */ 1688 if (lp->lwp_mpflags & LWP_MP_WSTOP) { 1689 atomic_clear_int(&lp->lwp_mpflags, 1690 LWP_MP_WSTOP); 1691 --p->p_nstopped; 1692 } else { 1693 if (bootverbose) 1694 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", 1695 p->p_pid, lp->lwp_tid); 1696 } 1697 /* FALLTHROUGH */ 1698 1699 case LSSTOP: 1700 /* 1701 * This handles any lwp's waiting in a tsleep with 1702 * SIGCATCH. 1703 */ 1704 lwp_signotify(lp); 1705 break; 1706 1707 } 1708 lwkt_reltoken(&lp->lwp_token); 1709 LWPRELE(lp); 1710 } 1711 1712 /* 1713 * This handles any lwp's waiting in tstop(). We have interlocked 1714 * the setting of p_stat by acquiring and releasing each lpw's 1715 * token. 1716 */ 1717 wakeup(p); 1718 } 1719 1720 /* 1721 * Wait for all threads except the current thread to stop. 1722 */ 1723 static void 1724 proc_stopwait(struct proc *p) 1725 { 1726 while ((p->p_stat == SSTOP || p->p_stat == SCORE) && 1727 p->p_nstopped < p->p_nthreads - 1) { 1728 tsleep_interlock(&p->p_nstopped, 0); 1729 if (p->p_nstopped < p->p_nthreads - 1) { 1730 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); 1731 } 1732 } 1733 } 1734 1735 /* 1736 * No requirements. 1737 */ 1738 static int 1739 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) 1740 { 1741 sigset_t savedmask, set; 1742 struct proc *p = curproc; 1743 struct lwp *lp = curthread->td_lwp; 1744 int error, sig, hz, timevalid = 0; 1745 struct timespec rts, ets, ts; 1746 struct timeval tv; 1747 1748 error = 0; 1749 sig = 0; 1750 ets.tv_sec = 0; /* silence compiler warning */ 1751 ets.tv_nsec = 0; /* silence compiler warning */ 1752 SIG_CANTMASK(waitset); 1753 savedmask = lp->lwp_sigmask; 1754 1755 if (timeout) { 1756 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && 1757 timeout->tv_nsec < 1000000000) { 1758 timevalid = 1; 1759 getnanouptime(&rts); 1760 timespecadd(&rts, timeout, &ets); 1761 } 1762 } 1763 1764 for (;;) { 1765 set = lwp_sigpend(lp); 1766 SIGSETAND(set, waitset); 1767 if ((sig = sig_ffs(&set)) != 0) { 1768 SIGFILLSET(lp->lwp_sigmask); 1769 SIGDELSET(lp->lwp_sigmask, sig); 1770 SIG_CANTMASK(lp->lwp_sigmask); 1771 sig = issignal(lp, 1, 0); 1772 /* 1773 * It may be a STOP signal, in the case, issignal 1774 * returns 0, because we may stop there, and new 1775 * signal can come in, we should restart if we got 1776 * nothing. 1777 */ 1778 if (sig == 0) 1779 continue; 1780 else 1781 break; 1782 } 1783 1784 /* 1785 * Previous checking got nothing, and we retried but still 1786 * got nothing, we should return the error status. 1787 */ 1788 if (error) 1789 break; 1790 1791 /* 1792 * POSIX says this must be checked after looking for pending 1793 * signals. 1794 */ 1795 if (timeout) { 1796 if (timevalid == 0) { 1797 error = EINVAL; 1798 break; 1799 } 1800 getnanouptime(&rts); 1801 if (timespeccmp(&rts, &ets, >=)) { 1802 error = EAGAIN; 1803 break; 1804 } 1805 timespecsub(&ets, &rts, &ts); 1806 TIMESPEC_TO_TIMEVAL(&tv, &ts); 1807 hz = tvtohz_high(&tv); 1808 } else { 1809 hz = 0; 1810 } 1811 1812 lp->lwp_sigmask = savedmask; 1813 SIGSETNAND(lp->lwp_sigmask, waitset); 1814 /* 1815 * We won't ever be woken up. Instead, our sleep will 1816 * be broken in lwpsignal(). 1817 */ 1818 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); 1819 if (timeout) { 1820 if (error == ERESTART) { 1821 /* can not restart a timeout wait. */ 1822 error = EINTR; 1823 } else if (error == EAGAIN) { 1824 /* will calculate timeout by ourself. */ 1825 error = 0; 1826 } 1827 } 1828 /* Retry ... */ 1829 } 1830 1831 lp->lwp_sigmask = savedmask; 1832 if (sig) { 1833 error = 0; 1834 bzero(info, sizeof(*info)); 1835 info->si_signo = sig; 1836 spin_lock(&lp->lwp_spin); 1837 lwp_delsig(lp, sig, 1); /* take the signal! */ 1838 spin_unlock(&lp->lwp_spin); 1839 1840 if (sig == SIGKILL) { 1841 sigexit(lp, sig); 1842 /* NOT REACHED */ 1843 } 1844 } 1845 1846 return (error); 1847 } 1848 1849 /* 1850 * MPALMOSTSAFE 1851 */ 1852 int 1853 sys_sigtimedwait(struct sysmsg *sysmsg, const struct sigtimedwait_args *uap) 1854 { 1855 struct timespec ts; 1856 struct timespec *timeout; 1857 sigset_t set; 1858 siginfo_t info; 1859 int error; 1860 1861 if (uap->timeout) { 1862 error = copyin(uap->timeout, &ts, sizeof(ts)); 1863 if (error) 1864 return (error); 1865 timeout = &ts; 1866 } else { 1867 timeout = NULL; 1868 } 1869 error = copyin(uap->set, &set, sizeof(set)); 1870 if (error) 1871 return (error); 1872 error = kern_sigtimedwait(set, &info, timeout); 1873 if (error) 1874 return (error); 1875 if (uap->info) 1876 error = copyout(&info, uap->info, sizeof(info)); 1877 /* Repost if we got an error. */ 1878 /* 1879 * XXX lwp 1880 * 1881 * This could transform a thread-specific signal to another 1882 * thread / process pending signal. 1883 */ 1884 if (error) { 1885 ksignal(curproc, info.si_signo); 1886 } else { 1887 sysmsg->sysmsg_result = info.si_signo; 1888 } 1889 return (error); 1890 } 1891 1892 /* 1893 * MPALMOSTSAFE 1894 */ 1895 int 1896 sys_sigwaitinfo(struct sysmsg *sysmsg, const struct sigwaitinfo_args *uap) 1897 { 1898 siginfo_t info; 1899 sigset_t set; 1900 int error; 1901 1902 error = copyin(uap->set, &set, sizeof(set)); 1903 if (error) 1904 return (error); 1905 error = kern_sigtimedwait(set, &info, NULL); 1906 if (error) 1907 return (error); 1908 if (uap->info) 1909 error = copyout(&info, uap->info, sizeof(info)); 1910 /* Repost if we got an error. */ 1911 /* 1912 * XXX lwp 1913 * 1914 * This could transform a thread-specific signal to another 1915 * thread / process pending signal. 1916 */ 1917 if (error) { 1918 ksignal(curproc, info.si_signo); 1919 } else { 1920 sysmsg->sysmsg_result = info.si_signo; 1921 } 1922 return (error); 1923 } 1924 1925 /* 1926 * If the current process has received a signal that would interrupt a 1927 * system call, return EINTR or ERESTART as appropriate. 1928 */ 1929 int 1930 iscaught(struct lwp *lp) 1931 { 1932 struct proc *p = lp->lwp_proc; 1933 int sig; 1934 1935 if (p) { 1936 if ((sig = CURSIG(lp)) != 0) { 1937 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) 1938 return (EINTR); 1939 return (ERESTART); 1940 } 1941 } 1942 return(EWOULDBLOCK); 1943 } 1944 1945 /* 1946 * If the current lwp/proc has received a signal (should be caught or cause 1947 * termination, should interrupt current syscall), return the signal number. 1948 * Stop signals with default action are processed immediately, then cleared; 1949 * they aren't returned. This is checked after each entry to the system for 1950 * a syscall or trap (though this can usually be done without calling issignal 1951 * by checking the pending signal masks in the CURSIG macro). 1952 * 1953 * This routine is called via CURSIG/__cursig. We will acquire and release 1954 * p->p_token but if the caller needs to interlock the test the caller must 1955 * also hold p->p_token. 1956 * 1957 * while (sig = CURSIG(curproc)) 1958 * postsig(sig); 1959 */ 1960 int 1961 issignal(struct lwp *lp, int maytrace, int *ptokp) 1962 { 1963 struct proc *p = lp->lwp_proc; 1964 sigset_t mask; 1965 int sig, prop; 1966 int haveptok; 1967 1968 for (;;) { 1969 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); 1970 1971 haveptok = 0; 1972 1973 /* 1974 * NOTE: Do not tstop here. Issue the proc_stop() 1975 * so other parties see that we know we need 1976 * to stop, but don't block here. Locks might 1977 * be held. 1978 * 1979 * XXX If this process is supposed to stop, stop this thread. 1980 * removed. 1981 */ 1982 #if 0 1983 if (STOPLWP(p, lp)) { 1984 lwkt_gettoken(&p->p_token); 1985 tstop(); 1986 lwkt_reltoken(&p->p_token); 1987 } 1988 #endif 1989 1990 /* 1991 * Quick check without token 1992 */ 1993 mask = lwp_sigpend(lp); 1994 SIGSETNAND(mask, lp->lwp_sigmask); 1995 if (p->p_flags & P_PPWAIT) 1996 SIG_STOPSIGMASK(mask); 1997 SIG_CONDBLOCKALLSIGS(mask, lp); 1998 1999 if (SIGISEMPTY(mask)) /* no signal to send */ 2000 return (0); 2001 2002 /* 2003 * If the signal is a member of the process signal set 2004 * we need p_token (even if it is also a member of the 2005 * lwp signal set). 2006 */ 2007 sig = sig_ffs(&mask); 2008 if (SIGISMEMBER(p->p_siglist, sig)) { 2009 /* 2010 * Recheck with token 2011 */ 2012 haveptok = 1; 2013 lwkt_gettoken(&p->p_token); 2014 2015 mask = lwp_sigpend(lp); 2016 SIGSETNAND(mask, lp->lwp_sigmask); 2017 if (p->p_flags & P_PPWAIT) 2018 SIG_STOPSIGMASK(mask); 2019 if (SIGISEMPTY(mask)) { /* no signal to send */ 2020 /* haveptok is TRUE */ 2021 lwkt_reltoken(&p->p_token); 2022 return (0); 2023 } 2024 sig = sig_ffs(&mask); 2025 } 2026 2027 STOPEVENT(p, S_SIG, sig); 2028 2029 /* 2030 * We should see pending but ignored signals 2031 * only if P_TRACED was on when they were posted. 2032 */ 2033 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { 2034 spin_lock(&lp->lwp_spin); 2035 lwp_delsig(lp, sig, haveptok); 2036 spin_unlock(&lp->lwp_spin); 2037 if (haveptok) 2038 lwkt_reltoken(&p->p_token); 2039 continue; 2040 } 2041 if (maytrace && 2042 (p->p_flags & P_TRACED) && 2043 (p->p_flags & P_PPWAIT) == 0) { 2044 /* 2045 * If traced, always stop, and stay stopped until 2046 * released by the parent. 2047 * 2048 * NOTE: SSTOP may get cleared during the loop, but 2049 * we do not re-notify the parent if we have 2050 * to loop several times waiting for the parent 2051 * to let us continue. XXX not sure if this is 2052 * still true 2053 * 2054 * NOTE: Do not tstop here. Issue the proc_stop() 2055 * so other parties see that we know we need 2056 * to stop, but don't block here. Locks might 2057 * be held. 2058 */ 2059 if (haveptok == 0) { 2060 lwkt_gettoken(&p->p_token); 2061 haveptok = 1; 2062 } 2063 p->p_xstat = sig; 2064 proc_stop(p, SSTOP); 2065 2066 /* 2067 * Normally we don't stop until we return to userland, but 2068 * make an exception when tracing and 'maytrace' is asserted. 2069 */ 2070 if (p->p_flags & P_TRACED) 2071 tstop(); 2072 2073 /* 2074 * If parent wants us to take the signal, 2075 * then it will leave it in p->p_xstat; 2076 * otherwise we just look for signals again. 2077 */ 2078 spin_lock(&lp->lwp_spin); 2079 lwp_delsig(lp, sig, 1); /* clear old signal */ 2080 spin_unlock(&lp->lwp_spin); 2081 sig = p->p_xstat; 2082 if (sig == 0) { 2083 /* haveptok is TRUE */ 2084 lwkt_reltoken(&p->p_token); 2085 continue; 2086 } 2087 2088 /* 2089 * Put the new signal into p_siglist. If the 2090 * signal is being masked, look for other signals. 2091 * 2092 * XXX lwp might need a call to ksignal() 2093 */ 2094 SIGADDSET_ATOMIC(p->p_siglist, sig); 2095 if (SIGISMEMBER(lp->lwp_sigmask, sig)) { 2096 /* haveptok is TRUE */ 2097 lwkt_reltoken(&p->p_token); 2098 continue; 2099 } 2100 2101 /* 2102 * If the traced bit got turned off, go back up 2103 * to the top to rescan signals. This ensures 2104 * that p_sig* and ps_sigact are consistent. 2105 */ 2106 if ((p->p_flags & P_TRACED) == 0) { 2107 /* haveptok is TRUE */ 2108 lwkt_reltoken(&p->p_token); 2109 continue; 2110 } 2111 } 2112 2113 /* 2114 * p_token may be held here 2115 */ 2116 prop = sigprop(sig); 2117 2118 /* 2119 * Decide whether the signal should be returned. 2120 * Return the signal's number, or fall through 2121 * to clear it from the pending mask. 2122 */ 2123 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { 2124 case (intptr_t)SIG_DFL: 2125 /* 2126 * Don't take default actions on system processes. 2127 */ 2128 if (p->p_pid <= 1) { 2129 #ifdef DIAGNOSTIC 2130 /* 2131 * Are you sure you want to ignore SIGSEGV 2132 * in init? XXX 2133 */ 2134 kprintf("Process (pid %lu) got signal %d\n", 2135 (u_long)p->p_pid, sig); 2136 #endif 2137 break; /* == ignore */ 2138 } 2139 2140 /* 2141 * Handle the in-kernel checkpoint action 2142 */ 2143 if (prop & SA_CKPT) { 2144 if (haveptok == 0) { 2145 lwkt_gettoken(&p->p_token); 2146 haveptok = 1; 2147 } 2148 checkpoint_signal_handler(lp); 2149 break; 2150 } 2151 2152 /* 2153 * If there is a pending stop signal to process 2154 * with default action, stop here, 2155 * then clear the signal. However, 2156 * if process is member of an orphaned 2157 * process group, ignore tty stop signals. 2158 */ 2159 if (prop & SA_STOP) { 2160 if (haveptok == 0) { 2161 lwkt_gettoken(&p->p_token); 2162 haveptok = 1; 2163 } 2164 if (p->p_flags & P_TRACED || 2165 (p->p_pgrp->pg_jobc == 0 && 2166 prop & SA_TTYSTOP)) 2167 break; /* == ignore */ 2168 if ((p->p_flags & P_WEXIT) == 0) { 2169 /* 2170 * NOTE: We do not block here. Issue 2171 * stopthe stop so other parties 2172 * see that we know we need to 2173 * stop. Locks might be held. 2174 */ 2175 p->p_xstat = sig; 2176 proc_stop(p, SSTOP); 2177 2178 #if 0 2179 tstop(); 2180 #endif 2181 } 2182 break; 2183 } else if (prop & SA_IGNORE) { 2184 /* 2185 * Except for SIGCONT, shouldn't get here. 2186 * Default action is to ignore; drop it. 2187 */ 2188 break; /* == ignore */ 2189 } else { 2190 if (ptokp) 2191 *ptokp = haveptok; 2192 else if (haveptok) 2193 lwkt_reltoken(&p->p_token); 2194 return (sig); 2195 } 2196 2197 /*NOTREACHED*/ 2198 2199 case (intptr_t)SIG_IGN: 2200 /* 2201 * Masking above should prevent us ever trying 2202 * to take action on an ignored signal other 2203 * than SIGCONT, unless process is traced. 2204 */ 2205 if ((prop & SA_CONT) == 0 && 2206 (p->p_flags & P_TRACED) == 0) 2207 kprintf("issignal\n"); 2208 break; /* == ignore */ 2209 2210 default: 2211 /* 2212 * This signal has an action, let 2213 * postsig() process it. 2214 */ 2215 if (ptokp) 2216 *ptokp = haveptok; 2217 else if (haveptok) 2218 lwkt_reltoken(&p->p_token); 2219 return (sig); 2220 } 2221 spin_lock(&lp->lwp_spin); 2222 lwp_delsig(lp, sig, haveptok); /* take the signal! */ 2223 spin_unlock(&lp->lwp_spin); 2224 2225 if (haveptok) 2226 lwkt_reltoken(&p->p_token); 2227 } 2228 /* NOTREACHED */ 2229 } 2230 2231 /* 2232 * Take the action for the specified signal from the current set of 2233 * pending signals. 2234 * 2235 * haveptok indicates whether the caller is holding p->p_token. If the 2236 * caller is, we are responsible for releasing it. 2237 * 2238 * This routine can only be called from the top-level trap from usermode. 2239 * It is expecting to be able to modify the top-level stack frame. 2240 */ 2241 void 2242 postsig(int sig, int haveptok) 2243 { 2244 struct lwp *lp = curthread->td_lwp; 2245 struct proc *p = lp->lwp_proc; 2246 struct sigacts *ps = p->p_sigacts; 2247 sig_t action; 2248 sigset_t returnmask; 2249 int code; 2250 2251 KASSERT(sig != 0, ("postsig")); 2252 2253 /* 2254 * If we are a virtual kernel running an emulated user process 2255 * context, switch back to the virtual kernel context before 2256 * trying to post the signal. 2257 */ 2258 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 2259 struct trapframe *tf = lp->lwp_md.md_regs; 2260 tf->tf_trapno = 0; 2261 vkernel_trap(lp, tf); 2262 } 2263 2264 KNOTE(&p->p_klist, NOTE_SIGNAL | sig); 2265 2266 spin_lock(&lp->lwp_spin); 2267 lwp_delsig(lp, sig, haveptok); 2268 spin_unlock(&lp->lwp_spin); 2269 action = ps->ps_sigact[_SIG_IDX(sig)]; 2270 #ifdef KTRACE 2271 if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) 2272 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? 2273 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); 2274 #endif 2275 /* 2276 * We don't need p_token after this point. 2277 */ 2278 if (haveptok) 2279 lwkt_reltoken(&p->p_token); 2280 2281 STOPEVENT(p, S_SIG, sig); 2282 2283 if (action == SIG_DFL) { 2284 /* 2285 * Default action, where the default is to kill 2286 * the process. (Other cases were ignored above.) 2287 */ 2288 sigexit(lp, sig); 2289 /* NOTREACHED */ 2290 } else { 2291 /* 2292 * If we get here, the signal must be caught. 2293 */ 2294 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), 2295 ("postsig action")); 2296 2297 /* 2298 * Reset the signal handler if asked to 2299 */ 2300 if (SIGISMEMBER(ps->ps_sigreset, sig)) { 2301 /* 2302 * See kern_sigaction() for origin of this code. 2303 */ 2304 SIGDELSET(p->p_sigcatch, sig); 2305 if (sig != SIGCONT && 2306 sigprop(sig) & SA_IGNORE) 2307 SIGADDSET(p->p_sigignore, sig); 2308 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; 2309 } 2310 2311 /* 2312 * Set the signal mask and calculate the mask to restore 2313 * when the signal function returns. 2314 * 2315 * Special case: user has done a sigsuspend. Here the 2316 * current mask is not of interest, but rather the 2317 * mask from before the sigsuspend is what we want 2318 * restored after the signal processing is completed. 2319 */ 2320 if (lp->lwp_flags & LWP_OLDMASK) { 2321 returnmask = lp->lwp_oldsigmask; 2322 lp->lwp_flags &= ~LWP_OLDMASK; 2323 } else { 2324 returnmask = lp->lwp_sigmask; 2325 } 2326 2327 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); 2328 if (!SIGISMEMBER(ps->ps_signodefer, sig)) 2329 SIGADDSET(lp->lwp_sigmask, sig); 2330 2331 lp->lwp_ru.ru_nsignals++; 2332 if (lp->lwp_sig != sig) { 2333 code = 0; 2334 } else { 2335 code = lp->lwp_code; 2336 lp->lwp_code = 0; 2337 lp->lwp_sig = 0; 2338 } 2339 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); 2340 } 2341 } 2342 2343 /* 2344 * Kill the current process for stated reason. 2345 */ 2346 void 2347 killproc(struct proc *p, char *why) 2348 { 2349 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", 2350 p->p_pid, p->p_comm, 2351 p->p_ucred ? p->p_ucred->cr_uid : -1, why); 2352 ksignal(p, SIGKILL); 2353 } 2354 2355 /* 2356 * Force the current process to exit with the specified signal, dumping core 2357 * if appropriate. We bypass the normal tests for masked and caught signals, 2358 * allowing unrecoverable failures to terminate the process without changing 2359 * signal state. Mark the accounting record with the signal termination. 2360 * If dumping core, save the signal number for the debugger. Calls exit and 2361 * does not return. 2362 * 2363 * This routine does not return. 2364 */ 2365 void 2366 sigexit(struct lwp *lp, int sig) 2367 { 2368 struct proc *p = lp->lwp_proc; 2369 2370 lwkt_gettoken(&p->p_token); 2371 p->p_acflag |= AXSIG; 2372 if (sigprop(sig) & SA_CORE) { 2373 lp->lwp_sig = sig; 2374 2375 /* 2376 * All threads must be stopped before we can safely coredump. 2377 * Stop threads using SCORE, which cannot be overridden. 2378 */ 2379 if (p->p_stat != SCORE) { 2380 proc_stop(p, SCORE); 2381 proc_stopwait(p); 2382 2383 if (coredump(lp, sig) == 0) 2384 sig |= WCOREFLAG; 2385 p->p_stat = SSTOP; 2386 } 2387 2388 /* 2389 * Log signals which would cause core dumps 2390 * (Log as LOG_INFO to appease those who don't want 2391 * these messages.) 2392 * XXX : Todo, as well as euid, write out ruid too 2393 */ 2394 if (kern_logsigexit) { 2395 log(LOG_INFO, 2396 "pid %d (%s), uid %d: exited on signal %d%s\n", 2397 p->p_pid, p->p_comm, 2398 p->p_ucred ? p->p_ucred->cr_uid : -1, 2399 sig &~ WCOREFLAG, 2400 sig & WCOREFLAG ? " (core dumped)" : ""); 2401 if (kern_logsigexit > 1) 2402 kprintf("DEBUG - waiting on kern.logsigexit\n"); 2403 while (kern_logsigexit > 1) { 2404 tsleep(&kern_logsigexit, 0, "DEBUG", hz); 2405 } 2406 } 2407 } 2408 lwkt_reltoken(&p->p_token); 2409 exit1(W_EXITCODE(0, sig)); 2410 /* NOTREACHED */ 2411 } 2412 2413 static char corefilename[MAXPATHLEN+1] = {"%N.core"}; 2414 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, 2415 sizeof(corefilename), "process corefile name format string"); 2416 2417 /* 2418 * expand_name(name, uid, pid) 2419 * Expand the name described in corefilename, using name, uid, and pid. 2420 * corefilename is a kprintf-like string, with three format specifiers: 2421 * %N name of process ("name") 2422 * %P process id (pid) 2423 * %U user id (uid) 2424 * For example, "%N.core" is the default; they can be disabled completely 2425 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". 2426 * This is controlled by the sysctl variable kern.corefile (see above). 2427 */ 2428 2429 static char * 2430 expand_name(const char *name, uid_t uid, pid_t pid) 2431 { 2432 char *temp; 2433 char buf[11]; /* Buffer for pid/uid -- max 4B */ 2434 int i, n; 2435 char *format = corefilename; 2436 size_t namelen; 2437 2438 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); 2439 if (temp == NULL) 2440 return NULL; 2441 namelen = strlen(name); 2442 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { 2443 int l; 2444 switch (format[i]) { 2445 case '%': /* Format character */ 2446 i++; 2447 switch (format[i]) { 2448 case '%': 2449 temp[n++] = '%'; 2450 break; 2451 case 'N': /* process name */ 2452 if ((n + namelen) > MAXPATHLEN) { 2453 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2454 pid, name, uid, temp, name); 2455 kfree(temp, M_TEMP); 2456 return NULL; 2457 } 2458 memcpy(temp+n, name, namelen); 2459 n += namelen; 2460 break; 2461 case 'P': /* process id */ 2462 l = ksprintf(buf, "%u", pid); 2463 if ((n + l) > MAXPATHLEN) { 2464 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2465 pid, name, uid, temp, name); 2466 kfree(temp, M_TEMP); 2467 return NULL; 2468 } 2469 memcpy(temp+n, buf, l); 2470 n += l; 2471 break; 2472 case 'U': /* user id */ 2473 l = ksprintf(buf, "%u", uid); 2474 if ((n + l) > MAXPATHLEN) { 2475 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", 2476 pid, name, uid, temp, name); 2477 kfree(temp, M_TEMP); 2478 return NULL; 2479 } 2480 memcpy(temp+n, buf, l); 2481 n += l; 2482 break; 2483 default: 2484 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); 2485 } 2486 break; 2487 default: 2488 temp[n++] = format[i]; 2489 } 2490 } 2491 temp[n] = '\0'; 2492 return temp; 2493 } 2494 2495 /* 2496 * Dump a process' core. The main routine does some 2497 * policy checking, and creates the name of the coredump; 2498 * then it passes on a vnode and a size limit to the process-specific 2499 * coredump routine if there is one; if there _is not_ one, it returns 2500 * ENOSYS; otherwise it returns the error from the process-specific routine. 2501 * 2502 * The parameter `lp' is the lwp which triggered the coredump. 2503 */ 2504 2505 static int 2506 coredump(struct lwp *lp, int sig) 2507 { 2508 struct proc *p = lp->lwp_proc; 2509 struct vnode *vp; 2510 struct ucred *cred = p->p_ucred; 2511 struct flock lf; 2512 struct nlookupdata nd; 2513 struct vattr vattr; 2514 int error, error1; 2515 char *name; /* name of corefile */ 2516 off_t limit; 2517 2518 STOPEVENT(p, S_CORE, 0); 2519 2520 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0) 2521 return (EFAULT); 2522 2523 /* 2524 * Note that the bulk of limit checking is done after 2525 * the corefile is created. The exception is if the limit 2526 * for corefiles is 0, in which case we don't bother 2527 * creating the corefile at all. This layout means that 2528 * a corefile is truncated instead of not being created, 2529 * if it is larger than the limit. 2530 */ 2531 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; 2532 if (limit == 0) 2533 return EFBIG; 2534 2535 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); 2536 if (name == NULL) 2537 return (EINVAL); 2538 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); 2539 if (error == 0) 2540 error = vn_open(&nd, NULL, 2541 O_CREAT | FWRITE | O_NOFOLLOW, 2542 S_IRUSR | S_IWUSR); 2543 kfree(name, M_TEMP); 2544 if (error) { 2545 nlookup_done(&nd); 2546 return (error); 2547 } 2548 vp = nd.nl_open_vp; 2549 nd.nl_open_vp = NULL; 2550 nlookup_done(&nd); 2551 2552 vn_unlock(vp); 2553 lf.l_whence = SEEK_SET; 2554 lf.l_start = 0; 2555 lf.l_len = 0; 2556 lf.l_type = F_WRLCK; 2557 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); 2558 if (error) 2559 goto out2; 2560 2561 /* Don't dump to non-regular files or files with links. */ 2562 if (vp->v_type != VREG || 2563 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { 2564 error = EFAULT; 2565 goto out1; 2566 } 2567 2568 /* Don't dump to files current user does not own */ 2569 if (vattr.va_uid != p->p_ucred->cr_uid) { 2570 error = EFAULT; 2571 goto out1; 2572 } 2573 2574 VATTR_NULL(&vattr); 2575 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2576 vattr.va_size = 0; 2577 VOP_SETATTR(vp, &vattr, cred); 2578 p->p_acflag |= ACORE; 2579 vn_unlock(vp); 2580 2581 error = p->p_sysent->sv_coredump ? 2582 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; 2583 2584 out1: 2585 lf.l_type = F_UNLCK; 2586 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); 2587 out2: 2588 error1 = vn_close(vp, FWRITE, NULL); 2589 if (error == 0) 2590 error = error1; 2591 return (error); 2592 } 2593 2594 /* 2595 * Nonexistent system call-- signal process (may want to handle it). 2596 * Flag error in case process won't see signal immediately (blocked or ignored). 2597 * 2598 * MPALMOSTSAFE 2599 */ 2600 /* ARGSUSED */ 2601 int 2602 sys_nosys(struct sysmsg *sysmsg, const struct nosys_args *args) 2603 { 2604 lwpsignal(curproc, curthread->td_lwp, SIGSYS); 2605 return (EINVAL); 2606 } 2607 2608 /* 2609 * Send a SIGIO or SIGURG signal to a process or process group using 2610 * stored credentials rather than those of the current process. 2611 */ 2612 void 2613 pgsigio(struct sigio *sigio, int sig, int checkctty) 2614 { 2615 if (sigio == NULL) 2616 return; 2617 2618 if (sigio->sio_pgid > 0) { 2619 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, 2620 sigio->sio_proc)) 2621 ksignal(sigio->sio_proc, sig); 2622 } else if (sigio->sio_pgid < 0) { 2623 struct proc *p; 2624 struct pgrp *pg = sigio->sio_pgrp; 2625 2626 /* 2627 * Must interlock all signals against fork 2628 */ 2629 pgref(pg); 2630 lockmgr(&pg->pg_lock, LK_EXCLUSIVE); 2631 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 2632 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && 2633 (checkctty == 0 || (p->p_flags & P_CONTROLT))) 2634 ksignal(p, sig); 2635 } 2636 lockmgr(&pg->pg_lock, LK_RELEASE); 2637 pgrel(pg); 2638 } 2639 } 2640 2641 static int 2642 filt_sigattach(struct knote *kn) 2643 { 2644 struct proc *p = curproc; 2645 2646 kn->kn_ptr.p_proc = p; 2647 kn->kn_flags |= EV_CLEAR; /* automatically set */ 2648 2649 /* XXX lock the proc here while adding to the list? */ 2650 knote_insert(&p->p_klist, kn); 2651 2652 return (0); 2653 } 2654 2655 static void 2656 filt_sigdetach(struct knote *kn) 2657 { 2658 struct proc *p = kn->kn_ptr.p_proc; 2659 2660 knote_remove(&p->p_klist, kn); 2661 } 2662 2663 /* 2664 * signal knotes are shared with proc knotes, so we apply a mask to 2665 * the hint in order to differentiate them from process hints. This 2666 * could be avoided by using a signal-specific knote list, but probably 2667 * isn't worth the trouble. 2668 */ 2669 static int 2670 filt_signal(struct knote *kn, long hint) 2671 { 2672 if (hint & NOTE_SIGNAL) { 2673 hint &= ~NOTE_SIGNAL; 2674 2675 if (kn->kn_id == hint) 2676 kn->kn_data++; 2677 } 2678 return (kn->kn_data != 0); 2679 } 2680