1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 39 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $ 40 * $DragonFly: src/sys/kern/kern_exit.c,v 1.84 2007/07/12 21:56:22 dillon Exp $ 41 */ 42 43 #include "opt_compat.h" 44 #include "opt_ktrace.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/sysproto.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/proc.h> 52 #include <sys/ktrace.h> 53 #include <sys/pioctl.h> 54 #include <sys/tty.h> 55 #include <sys/wait.h> 56 #include <sys/vnode.h> 57 #include <sys/resourcevar.h> 58 #include <sys/signalvar.h> 59 #include <sys/taskqueue.h> 60 #include <sys/ptrace.h> 61 #include <sys/acct.h> /* for acct_process() function prototype */ 62 #include <sys/filedesc.h> 63 #include <sys/shm.h> 64 #include <sys/sem.h> 65 #include <sys/aio.h> 66 #include <sys/jail.h> 67 #include <sys/kern_syscall.h> 68 #include <sys/upcall.h> 69 #include <sys/caps.h> 70 #include <sys/unistd.h> 71 72 #include <vm/vm.h> 73 #include <vm/vm_param.h> 74 #include <sys/lock.h> 75 #include <vm/pmap.h> 76 #include <vm/vm_map.h> 77 #include <vm/vm_zone.h> 78 #include <vm/vm_extern.h> 79 #include <sys/user.h> 80 81 #include <sys/thread2.h> 82 #include <sys/sysref2.h> 83 84 static void reaplwps(void *context, int dummy); 85 static void killlwps(struct lwp *lp); 86 87 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); 88 static MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 89 90 /* 91 * callout list for things to do at exit time 92 */ 93 struct exitlist { 94 exitlist_fn function; 95 TAILQ_ENTRY(exitlist) next; 96 }; 97 98 TAILQ_HEAD(exit_list_head, exitlist); 99 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); 100 101 /* 102 * LWP reaper data 103 */ 104 struct task *deadlwp_task[MAXCPU]; 105 struct lwplist deadlwp_list[MAXCPU]; 106 107 /* 108 * exit -- 109 * Death of process. 110 * 111 * SYS_EXIT_ARGS(int rval) 112 */ 113 int 114 sys_exit(struct exit_args *uap) 115 { 116 exit1(W_EXITCODE(uap->rval, 0)); 117 /* NOTREACHED */ 118 } 119 120 /* 121 * Extended exit -- 122 * Death of a lwp or process with optional bells and whistles. 123 */ 124 int 125 sys_extexit(struct extexit_args *uap) 126 { 127 int action, who; 128 int error; 129 130 action = EXTEXIT_ACTION(uap->how); 131 who = EXTEXIT_WHO(uap->how); 132 133 /* Check parameters before we might perform some action */ 134 switch (who) { 135 case EXTEXIT_PROC: 136 case EXTEXIT_LWP: 137 break; 138 139 default: 140 return (EINVAL); 141 } 142 143 switch (action) { 144 case EXTEXIT_SIMPLE: 145 break; 146 147 case EXTEXIT_SETINT: 148 error = copyout(&uap->status, uap->addr, sizeof(uap->status)); 149 if (error) 150 return (error); 151 break; 152 153 default: 154 return (EINVAL); 155 } 156 157 switch (who) { 158 case EXTEXIT_LWP: 159 /* 160 * Be sure only to perform a simple lwp exit if there is at 161 * least one more lwp in the proc, which will call exit1() 162 * later, otherwise the proc will be an UNDEAD and not even a 163 * SZOMB! 164 */ 165 if (curproc->p_nthreads > 1) { 166 lwp_exit(0); 167 /* NOT REACHED */ 168 } 169 /* else last lwp in proc: do the real thing */ 170 /* FALLTHROUGH */ 171 172 default: /* to help gcc */ 173 case EXTEXIT_PROC: 174 exit1(W_EXITCODE(uap->status, 0)); 175 /* NOTREACHED */ 176 } 177 178 /* NOTREACHED */ 179 } 180 181 /* 182 * Kill all lwps associated with the current process except the 183 * current lwp. Return an error if we race another thread trying to 184 * do the same thing and lose the race. 185 * 186 * If forexec is non-zero the current thread and process flags are 187 * cleaned up so they can be reused. 188 */ 189 int 190 killalllwps(int forexec) 191 { 192 struct lwp *lp = curthread->td_lwp; 193 struct proc *p = lp->lwp_proc; 194 195 /* 196 * Interlock against P_WEXIT. Only one of the process's thread 197 * is allowed to do the master exit. 198 */ 199 if (p->p_flag & P_WEXIT) 200 return (EALREADY); 201 p->p_flag |= P_WEXIT; 202 203 /* 204 * Interlock with LWP_WEXIT and kill any remaining LWPs 205 */ 206 lp->lwp_flag |= LWP_WEXIT; 207 if (p->p_nthreads > 1) 208 killlwps(lp); 209 210 /* 211 * If doing this for an exec, clean up the remaining thread 212 * (us) for continuing operation after all the other threads 213 * have been killed. 214 */ 215 if (forexec) { 216 lp->lwp_flag &= ~LWP_WEXIT; 217 p->p_flag &= ~P_WEXIT; 218 } 219 return(0); 220 } 221 222 /* 223 * Kill all LWPs except the current one. Do not try to signal 224 * LWPs which have exited on their own or have already been 225 * signaled. 226 */ 227 static void 228 killlwps(struct lwp *lp) 229 { 230 struct proc *p = lp->lwp_proc; 231 struct lwp *tlp; 232 233 /* 234 * Kill the remaining LWPs, interlock with LWP_WEXIT. 235 */ 236 FOREACH_LWP_IN_PROC(tlp, p) { 237 if ((tlp->lwp_flag & LWP_WEXIT) == 0) { 238 lwpsignal(p, tlp, SIGKILL); 239 tlp->lwp_flag |= LWP_WEXIT; 240 } 241 } 242 243 /* 244 * Wait for everything to clear out. 245 */ 246 while (p->p_nthreads > 1) { 247 if (bootverbose) 248 kprintf("killlwps: waiting for %d lwps of pid " 249 "%d to die\n", 250 p->p_nthreads - 1, p->p_pid); 251 tsleep(&p->p_nthreads, 0, "killlwps", hz); 252 } 253 } 254 255 /* 256 * Exit: deallocate address space and other resources, change proc state 257 * to zombie, and unlink proc from allproc and parent's lists. Save exit 258 * status and rusage for wait(). Check for child processes and orphan them. 259 */ 260 void 261 exit1(int rv) 262 { 263 struct thread *td = curthread; 264 struct proc *p = td->td_proc; 265 struct lwp *lp = td->td_lwp; 266 struct proc *q, *nq; 267 struct vmspace *vm; 268 struct vnode *vtmp; 269 struct exitlist *ep; 270 int error; 271 272 if (p->p_pid == 1) { 273 kprintf("init died (signal %d, exit %d)\n", 274 WTERMSIG(rv), WEXITSTATUS(rv)); 275 panic("Going nowhere without my init!"); 276 } 277 278 /* 279 * Kill all lwps associated with the current process, return an 280 * error if we race another thread trying to do the same thing 281 * and lose the race. 282 */ 283 error = killalllwps(0); 284 if (error) { 285 lwp_exit(0); 286 /* NOT REACHED */ 287 } 288 289 caps_exit(lp->lwp_thread); 290 aio_proc_rundown(p); 291 292 /* are we a task leader? */ 293 if (p == p->p_leader) { 294 struct kill_args killArgs; 295 killArgs.signum = SIGKILL; 296 q = p->p_peers; 297 while(q) { 298 killArgs.pid = q->p_pid; 299 /* 300 * The interface for kill is better 301 * than the internal signal 302 */ 303 sys_kill(&killArgs); 304 nq = q; 305 q = q->p_peers; 306 } 307 while (p->p_peers) 308 tsleep((caddr_t)p, 0, "exit1", 0); 309 } 310 311 #ifdef PGINPROF 312 vmsizmon(); 313 #endif 314 STOPEVENT(p, S_EXIT, rv); 315 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 316 317 /* 318 * Check if any loadable modules need anything done at process exit. 319 * e.g. SYSV IPC stuff 320 * XXX what if one of these generates an error? 321 */ 322 TAILQ_FOREACH(ep, &exit_list, next) 323 (*ep->function)(td); 324 325 if (p->p_flag & P_PROFIL) 326 stopprofclock(p); 327 /* 328 * If parent is waiting for us to exit or exec, 329 * P_PPWAIT is set; we will wakeup the parent below. 330 */ 331 p->p_flag &= ~(P_TRACED | P_PPWAIT); 332 SIGEMPTYSET(p->p_siglist); 333 SIGEMPTYSET(lp->lwp_siglist); 334 if (timevalisset(&p->p_realtimer.it_value)) 335 callout_stop(&p->p_ithandle); 336 337 /* 338 * Reset any sigio structures pointing to us as a result of 339 * F_SETOWN with our pid. 340 */ 341 funsetownlst(&p->p_sigiolst); 342 343 /* 344 * Close open files and release open-file table. 345 * This may block! 346 */ 347 fdfree(p); 348 p->p_fd = NULL; 349 350 if(p->p_leader->p_peers) { 351 q = p->p_leader; 352 while(q->p_peers != p) 353 q = q->p_peers; 354 q->p_peers = p->p_peers; 355 wakeup((caddr_t)p->p_leader); 356 } 357 358 /* 359 * XXX Shutdown SYSV semaphores 360 */ 361 semexit(p); 362 363 KKASSERT(p->p_numposixlocks == 0); 364 365 /* The next two chunks should probably be moved to vmspace_exit. */ 366 vm = p->p_vmspace; 367 368 /* 369 * Release upcalls associated with this process 370 */ 371 if (vm->vm_upcalls) 372 upc_release(vm, lp); 373 374 /* 375 * Clean up data related to virtual kernel operation. Clean up 376 * any vkernel context related to the current lwp now so we can 377 * destroy p_vkernel. 378 */ 379 if (p->p_vkernel) { 380 vkernel_lwp_exit(lp); 381 vkernel_exit(p); 382 } 383 384 /* 385 * Release user portion of address space. 386 * This releases references to vnodes, 387 * which could cause I/O if the file has been unlinked. 388 * Need to do this early enough that we can still sleep. 389 * Can't free the entire vmspace as the kernel stack 390 * may be mapped within that space also. 391 * 392 * Processes sharing the same vmspace may exit in one order, and 393 * get cleaned up by vmspace_exit() in a different order. The 394 * last exiting process to reach this point releases as much of 395 * the environment as it can, and the last process cleaned up 396 * by vmspace_exit() (which decrements exitingcnt) cleans up the 397 * remainder. 398 */ 399 ++vm->vm_exitingcnt; 400 sysref_put(&vm->vm_sysref); 401 402 if (SESS_LEADER(p)) { 403 struct session *sp = p->p_session; 404 405 if (sp->s_ttyvp) { 406 /* 407 * We are the controlling process. Signal the 408 * foreground process group, drain the controlling 409 * terminal, and revoke access to the controlling 410 * terminal. 411 * 412 * NOTE: while waiting for the process group to exit 413 * it is possible that one of the processes in the 414 * group will revoke the tty, so the ttyclosesession() 415 * function will re-check sp->s_ttyvp. 416 */ 417 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 418 if (sp->s_ttyp->t_pgrp) 419 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 420 ttywait(sp->s_ttyp); 421 ttyclosesession(sp, 1); /* also revoke */ 422 } 423 /* 424 * Release the tty. If someone has it open via 425 * /dev/tty then close it (since they no longer can 426 * once we've NULL'd it out). 427 */ 428 ttyclosesession(sp, 0); 429 430 /* 431 * s_ttyp is not zero'd; we use this to indicate 432 * that the session once had a controlling terminal. 433 * (for logging and informational purposes) 434 */ 435 } 436 sp->s_leader = NULL; 437 } 438 fixjobc(p, p->p_pgrp, 0); 439 (void)acct_process(p); 440 #ifdef KTRACE 441 /* 442 * release trace file 443 */ 444 if (p->p_tracenode) 445 ktrdestroy(&p->p_tracenode); 446 p->p_traceflag = 0; 447 #endif 448 /* 449 * Release reference to text vnode 450 */ 451 if ((vtmp = p->p_textvp) != NULL) { 452 p->p_textvp = NULL; 453 vrele(vtmp); 454 } 455 456 /* 457 * Move the process to the zombie list. This will block 458 * until the process p_lock count reaches 0. The process will 459 * not be reaped until TDF_EXITING is set by cpu_thread_exit(), 460 * which is called from cpu_proc_exit(). 461 */ 462 proc_move_allproc_zombie(p); 463 464 q = LIST_FIRST(&p->p_children); 465 if (q) /* only need this if any child is S_ZOMB */ 466 wakeup((caddr_t) initproc); 467 for (; q != 0; q = nq) { 468 nq = LIST_NEXT(q, p_sibling); 469 LIST_REMOVE(q, p_sibling); 470 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); 471 q->p_pptr = initproc; 472 q->p_sigparent = SIGCHLD; 473 /* 474 * Traced processes are killed 475 * since their existence means someone is screwing up. 476 */ 477 if (q->p_flag & P_TRACED) { 478 q->p_flag &= ~P_TRACED; 479 ksignal(q, SIGKILL); 480 } 481 } 482 483 /* 484 * Save exit status and final rusage info, adding in child rusage 485 * info and self times. 486 */ 487 p->p_xstat = rv; 488 calcru_proc(p, &p->p_ru); 489 ruadd(&p->p_ru, &p->p_cru); 490 491 /* 492 * notify interested parties of our demise. 493 */ 494 KNOTE(&p->p_klist, NOTE_EXIT); 495 496 /* 497 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 498 * flag set, notify process 1 instead (and hope it will handle 499 * this situation). 500 */ 501 if (p->p_pptr->p_sigacts->ps_flag & PS_NOCLDWAIT) { 502 struct proc *pp = p->p_pptr; 503 proc_reparent(p, initproc); 504 /* 505 * If this was the last child of our parent, notify 506 * parent, so in case he was wait(2)ing, he will 507 * continue. 508 */ 509 if (LIST_EMPTY(&pp->p_children)) 510 wakeup((caddr_t)pp); 511 } 512 513 if (p->p_sigparent && p->p_pptr != initproc) { 514 ksignal(p->p_pptr, p->p_sigparent); 515 } else { 516 ksignal(p->p_pptr, SIGCHLD); 517 } 518 519 wakeup((caddr_t)p->p_pptr); 520 /* 521 * cpu_exit is responsible for clearing curproc, since 522 * it is heavily integrated with the thread/switching sequence. 523 * 524 * Other substructures are freed from wait(). 525 */ 526 plimit_free(&p->p_limit); 527 528 /* 529 * Release the current user process designation on the process so 530 * the userland scheduler can work in someone else. 531 */ 532 p->p_usched->release_curproc(lp); 533 534 /* 535 * Finally, call machine-dependent code to release as many of the 536 * lwp's resources as we can and halt execution of this thread. 537 */ 538 lwp_exit(1); 539 } 540 541 void 542 lwp_exit(int masterexit) 543 { 544 struct lwp *lp = curthread->td_lwp; 545 struct proc *p = lp->lwp_proc; 546 547 /* 548 * lwp_exit() may be called without setting LWP_WEXIT, so 549 * make sure it is set here. 550 */ 551 lp->lwp_flag |= LWP_WEXIT; 552 553 /* 554 * Clean up any virtualization 555 */ 556 if (lp->lwp_vkernel) 557 vkernel_lwp_exit(lp); 558 559 /* 560 * Nobody actually wakes us when the lock 561 * count reaches zero, so just wait one tick. 562 */ 563 while (lp->lwp_lock > 0) 564 tsleep(lp, 0, "lwpexit", 1); 565 566 /* Hand down resource usage to our proc */ 567 ruadd(&p->p_ru, &lp->lwp_ru); 568 569 /* 570 * If we don't hold the process until the LWP is reaped wait*() 571 * may try to dispose of its vmspace before all the LWPs have 572 * actually terminated. 573 */ 574 PHOLD(p); 575 576 /* 577 * We have to use the reaper for all the LWPs except the one doing 578 * the master exit. The LWP doing the master exit can just be 579 * left on p_lwps and the process reaper will deal with it 580 * synchronously, which is much faster. 581 */ 582 if (masterexit == 0) { 583 LIST_REMOVE(lp, lwp_list); 584 --p->p_nthreads; 585 wakeup(&p->p_nthreads); 586 LIST_INSERT_HEAD(&deadlwp_list[mycpuid], lp, lwp_list); 587 taskqueue_enqueue(taskqueue_thread[mycpuid], deadlwp_task[mycpuid]); 588 } else { 589 --p->p_nthreads; 590 } 591 cpu_lwp_exit(); 592 } 593 594 /* 595 * Wait until a lwp is completely dead. 596 * 597 * If the thread is still executing, which can't be waited upon, 598 * return failure. The caller is responsible of waiting a little 599 * bit and checking again. 600 * 601 * Suggested use: 602 * while (!lwp_wait(lp)) 603 * tsleep(lp, 0, "lwpwait", 1); 604 */ 605 static int 606 lwp_wait(struct lwp *lp) 607 { 608 struct thread *td = lp->lwp_thread;; 609 610 KKASSERT(lwkt_preempted_proc() != lp); 611 612 while (lp->lwp_lock > 0) 613 tsleep(lp, 0, "lwpwait1", 1); 614 615 lwkt_wait_free(td); 616 617 /* 618 * The lwp's thread may still be in the middle 619 * of switching away, we can't rip its stack out from 620 * under it until TDF_EXITING is set and both 621 * TDF_RUNNING and TDF_PREEMPT_LOCK are clear. 622 * TDF_PREEMPT_LOCK must be checked because TDF_RUNNING 623 * will be cleared temporarily if a thread gets 624 * preempted. 625 * 626 * YYY no wakeup occurs, so we simply return failure 627 * and let the caller deal with sleeping and calling 628 * us again. 629 */ 630 if ((td->td_flags & (TDF_RUNNING|TDF_PREEMPT_LOCK|TDF_EXITING)) != 631 TDF_EXITING) 632 return (0); 633 634 return (1); 635 } 636 637 /* 638 * Release the resources associated with a lwp. 639 * The lwp must be completely dead. 640 */ 641 void 642 lwp_dispose(struct lwp *lp) 643 { 644 struct thread *td = lp->lwp_thread;; 645 646 KKASSERT(lwkt_preempted_proc() != lp); 647 KKASSERT(td->td_refs == 0); 648 KKASSERT((td->td_flags & (TDF_RUNNING|TDF_PREEMPT_LOCK|TDF_EXITING)) == 649 TDF_EXITING); 650 651 PRELE(lp->lwp_proc); 652 lp->lwp_proc = NULL; 653 if (td != NULL) { 654 td->td_proc = NULL; 655 td->td_lwp = NULL; 656 lp->lwp_thread = NULL; 657 lwkt_free_thread(td); 658 } 659 zfree(lwp_zone, lp); 660 } 661 662 int 663 sys_wait4(struct wait_args *uap) 664 { 665 struct rusage rusage; 666 int error, status; 667 668 error = kern_wait(uap->pid, uap->status ? &status : NULL, 669 uap->options, uap->rusage ? &rusage : NULL, &uap->sysmsg_fds[0]); 670 671 if (error == 0 && uap->status) 672 error = copyout(&status, uap->status, sizeof(*uap->status)); 673 if (error == 0 && uap->rusage) 674 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage)); 675 return (error); 676 } 677 678 /* 679 * wait1() 680 * 681 * wait_args(int pid, int *status, int options, struct rusage *rusage) 682 */ 683 int 684 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res) 685 { 686 struct thread *td = curthread; 687 struct proc *q = td->td_proc; 688 struct proc *p, *t; 689 int nfound, error; 690 691 if (pid == 0) 692 pid = -q->p_pgid; 693 if (options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) 694 return (EINVAL); 695 loop: 696 /* 697 * Hack for backwards compatibility with badly written user code. 698 * Or perhaps we have to do this anyway, it is unclear. XXX 699 * 700 * The problem is that if a process group is stopped and the parent 701 * is doing a wait*(..., WUNTRACED, ...), it will see the STOP 702 * of the child and then stop itself when it tries to return from the 703 * system call. When the process group is resumed the parent will 704 * then get the STOP status even though the child has now resumed 705 * (a followup wait*() will get the CONT status). 706 * 707 * Previously the CONT would overwrite the STOP because the tstop 708 * was handled within tsleep(), and the parent would only see 709 * the CONT when both are stopped and continued together. This litte 710 * two-line hack restores this effect. 711 */ 712 while (q->p_stat == SSTOP) 713 tstop(); 714 715 nfound = 0; 716 LIST_FOREACH(p, &q->p_children, p_sibling) { 717 if (pid != WAIT_ANY && 718 p->p_pid != pid && p->p_pgid != -pid) 719 continue; 720 721 /* This special case handles a kthread spawned by linux_clone 722 * (see linux_misc.c). The linux_wait4 and linux_waitpid 723 * functions need to be able to distinguish between waiting 724 * on a process and waiting on a thread. It is a thread if 725 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 726 * signifies we want to wait for threads and not processes. 727 */ 728 if ((p->p_sigparent != SIGCHLD) ^ 729 ((options & WLINUXCLONE) != 0)) { 730 continue; 731 } 732 733 nfound++; 734 if (p->p_stat == SZOMB) { 735 /* 736 * Reap any LWPs left in p->p_lwps. This is usually 737 * just the last LWP. This must be done before 738 * we loop on p_lock since the lwps hold a ref on 739 * it as a vmspace interlock. 740 * 741 * Once that is accomplished p_nthreads had better 742 * be zero. 743 */ 744 reaplwps(&p->p_lwps, 0); 745 KKASSERT(p->p_nthreads == 0); 746 747 /* 748 * Don't do anything really bad until all references 749 * to the process go away. This may include other 750 * LWPs which are still in the process of being 751 * reaped. We can't just pull the rug out from under 752 * them because they may still be using the VM space. 753 * 754 * Certain kernel facilities such as /proc will also 755 * put a hold on the process for short periods of 756 * time. 757 */ 758 while (p->p_lock) 759 tsleep(p, 0, "reap3", hz); 760 761 /* scheduling hook for heuristic */ 762 /* XXX no lwp available, we need a different heuristic */ 763 /* 764 p->p_usched->heuristic_exiting(td->td_lwp, deadlp); 765 */ 766 767 /* Take care of our return values. */ 768 *res = p->p_pid; 769 if (status) 770 *status = p->p_xstat; 771 if (rusage) 772 *rusage = p->p_ru; 773 /* 774 * If we got the child via a ptrace 'attach', 775 * we need to give it back to the old parent. 776 */ 777 if (p->p_oppid && (t = pfind(p->p_oppid))) { 778 p->p_oppid = 0; 779 proc_reparent(p, t); 780 ksignal(t, SIGCHLD); 781 wakeup((caddr_t)t); 782 return (0); 783 } 784 p->p_xstat = 0; 785 ruadd(&q->p_cru, &p->p_ru); 786 787 /* 788 * Decrement the count of procs running with this uid. 789 */ 790 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 791 792 /* 793 * Free up credentials. 794 */ 795 crfree(p->p_ucred); 796 p->p_ucred = NULL; 797 798 /* 799 * Remove unused arguments 800 */ 801 if (p->p_args && --p->p_args->ar_ref == 0) 802 FREE(p->p_args, M_PARGS); 803 804 /* 805 * Finally finished with old proc entry. 806 * Unlink it from its process group and free it. 807 */ 808 proc_remove_zombie(p); 809 leavepgrp(p); 810 811 if (--p->p_sigacts->ps_refcnt == 0) { 812 kfree(p->p_sigacts, M_SUBPROC); 813 p->p_sigacts = NULL; 814 } 815 816 vm_waitproc(p); 817 zfree(proc_zone, p); 818 nprocs--; 819 return (0); 820 } 821 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 822 (p->p_flag & P_TRACED || options & WUNTRACED)) { 823 p->p_flag |= P_WAITED; 824 825 *res = p->p_pid; 826 if (status) 827 *status = W_STOPCODE(p->p_xstat); 828 /* Zero rusage so we get something consistent. */ 829 if (rusage) 830 bzero(rusage, sizeof(rusage)); 831 return (0); 832 } 833 } 834 if (nfound == 0) 835 return (ECHILD); 836 if (options & WNOHANG) { 837 *res = 0; 838 return (0); 839 } 840 error = tsleep((caddr_t)q, PCATCH, "wait", 0); 841 if (error) 842 return (error); 843 goto loop; 844 } 845 846 /* 847 * make process 'parent' the new parent of process 'child'. 848 */ 849 void 850 proc_reparent(struct proc *child, struct proc *parent) 851 { 852 853 if (child->p_pptr == parent) 854 return; 855 856 LIST_REMOVE(child, p_sibling); 857 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 858 child->p_pptr = parent; 859 } 860 861 /* 862 * The next two functions are to handle adding/deleting items on the 863 * exit callout list 864 * 865 * at_exit(): 866 * Take the arguments given and put them onto the exit callout list, 867 * However first make sure that it's not already there. 868 * returns 0 on success. 869 */ 870 871 int 872 at_exit(exitlist_fn function) 873 { 874 struct exitlist *ep; 875 876 #ifdef INVARIANTS 877 /* Be noisy if the programmer has lost track of things */ 878 if (rm_at_exit(function)) 879 kprintf("WARNING: exit callout entry (%p) already present\n", 880 function); 881 #endif 882 ep = kmalloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); 883 if (ep == NULL) 884 return (ENOMEM); 885 ep->function = function; 886 TAILQ_INSERT_TAIL(&exit_list, ep, next); 887 return (0); 888 } 889 890 /* 891 * Scan the exit callout list for the given item and remove it. 892 * Returns the number of items removed (0 or 1) 893 */ 894 int 895 rm_at_exit(exitlist_fn function) 896 { 897 struct exitlist *ep; 898 899 TAILQ_FOREACH(ep, &exit_list, next) { 900 if (ep->function == function) { 901 TAILQ_REMOVE(&exit_list, ep, next); 902 kfree(ep, M_ATEXIT); 903 return(1); 904 } 905 } 906 return (0); 907 } 908 909 /* 910 * LWP reaper related code. 911 */ 912 static void 913 reaplwps(void *context, int dummy) 914 { 915 struct lwplist *lwplist = context; 916 struct lwp *lp; 917 918 while ((lp = LIST_FIRST(lwplist))) { 919 LIST_REMOVE(lp, lwp_list); 920 while (lwp_wait(lp) == 0) 921 tsleep(lp, 0, "lwpreap", 1); 922 lwp_dispose(lp); 923 } 924 } 925 926 static void 927 deadlwp_init(void) 928 { 929 int cpu; 930 931 for (cpu = 0; cpu < ncpus; cpu++) { 932 LIST_INIT(&deadlwp_list[cpu]); 933 deadlwp_task[cpu] = kmalloc(sizeof(*deadlwp_task[cpu]), M_DEVBUF, M_WAITOK); 934 TASK_INIT(deadlwp_task[cpu], 0, reaplwps, &deadlwp_list[cpu]); 935 } 936 } 937 938 SYSINIT(deadlwpinit, SI_SUB_CONFIGURE, SI_ORDER_ANY, deadlwp_init, NULL); 939