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_fork.c 8.6 (Berkeley) 4/8/94 39 * $FreeBSD: src/sys/kern/kern_fork.c,v 1.72.2.14 2003/06/26 04:15:10 silby Exp $ 40 * $DragonFly: src/sys/kern/kern_fork.c,v 1.74 2008/04/28 07:07:01 dillon Exp $ 41 */ 42 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/filedesc.h> 49 #include <sys/kernel.h> 50 #include <sys/sysctl.h> 51 #include <sys/malloc.h> 52 #include <sys/proc.h> 53 #include <sys/resourcevar.h> 54 #include <sys/vnode.h> 55 #include <sys/acct.h> 56 #include <sys/ktrace.h> 57 #include <sys/unistd.h> 58 #include <sys/jail.h> 59 #include <sys/caps.h> 60 61 #include <vm/vm.h> 62 #include <sys/lock.h> 63 #include <vm/pmap.h> 64 #include <vm/vm_map.h> 65 #include <vm/vm_extern.h> 66 #include <vm/vm_zone.h> 67 68 #include <sys/vmmeter.h> 69 #include <sys/thread2.h> 70 #include <sys/signal2.h> 71 72 static MALLOC_DEFINE(M_ATFORK, "atfork", "atfork callback"); 73 74 /* 75 * These are the stuctures used to create a callout list for things to do 76 * when forking a process 77 */ 78 struct forklist { 79 forklist_fn function; 80 TAILQ_ENTRY(forklist) next; 81 }; 82 83 TAILQ_HEAD(forklist_head, forklist); 84 static struct forklist_head fork_list = TAILQ_HEAD_INITIALIZER(fork_list); 85 86 static struct lwp *lwp_fork(struct lwp *, struct proc *, int flags); 87 88 int forksleep; /* Place for fork1() to sleep on. */ 89 90 /* 91 * Red-Black tree support for LWPs 92 */ 93 94 static int 95 rb_lwp_compare(struct lwp *lp1, struct lwp *lp2) 96 { 97 if (lp1->lwp_tid < lp2->lwp_tid) 98 return(-1); 99 if (lp1->lwp_tid > lp2->lwp_tid) 100 return(1); 101 return(0); 102 } 103 104 RB_GENERATE2(lwp_rb_tree, lwp, u.lwp_rbnode, rb_lwp_compare, lwpid_t, lwp_tid); 105 106 107 /* ARGSUSED */ 108 int 109 sys_fork(struct fork_args *uap) 110 { 111 struct lwp *lp = curthread->td_lwp; 112 struct proc *p2; 113 int error; 114 115 error = fork1(lp, RFFDG | RFPROC | RFPGLOCK, &p2); 116 if (error == 0) { 117 start_forked_proc(lp, p2); 118 uap->sysmsg_fds[0] = p2->p_pid; 119 uap->sysmsg_fds[1] = 0; 120 } 121 return error; 122 } 123 124 /* ARGSUSED */ 125 int 126 sys_vfork(struct vfork_args *uap) 127 { 128 struct lwp *lp = curthread->td_lwp; 129 struct proc *p2; 130 int error; 131 132 error = fork1(lp, RFFDG | RFPROC | RFPPWAIT | RFMEM | RFPGLOCK, &p2); 133 if (error == 0) { 134 start_forked_proc(lp, p2); 135 uap->sysmsg_fds[0] = p2->p_pid; 136 uap->sysmsg_fds[1] = 0; 137 } 138 return error; 139 } 140 141 /* 142 * Handle rforks. An rfork may (1) operate on the current process without 143 * creating a new, (2) create a new process that shared the current process's 144 * vmspace, signals, and/or descriptors, or (3) create a new process that does 145 * not share these things (normal fork). 146 * 147 * Note that we only call start_forked_proc() if a new process is actually 148 * created. 149 * 150 * rfork { int flags } 151 */ 152 int 153 sys_rfork(struct rfork_args *uap) 154 { 155 struct lwp *lp = curthread->td_lwp; 156 struct proc *p2; 157 int error; 158 159 if ((uap->flags & RFKERNELONLY) != 0) 160 return (EINVAL); 161 162 error = fork1(lp, uap->flags | RFPGLOCK, &p2); 163 if (error == 0) { 164 if (p2) 165 start_forked_proc(lp, p2); 166 uap->sysmsg_fds[0] = p2 ? p2->p_pid : 0; 167 uap->sysmsg_fds[1] = 0; 168 } 169 return error; 170 } 171 172 int 173 sys_lwp_create(struct lwp_create_args *uap) 174 { 175 struct proc *p = curproc; 176 struct lwp *lp; 177 struct lwp_params params; 178 int error; 179 180 error = copyin(uap->params, ¶ms, sizeof(params)); 181 if (error) 182 goto fail2; 183 184 lp = lwp_fork(curthread->td_lwp, p, RFPROC); 185 error = cpu_prepare_lwp(lp, ¶ms); 186 if (params.tid1 != NULL && 187 (error = copyout(&lp->lwp_tid, params.tid1, sizeof(lp->lwp_tid)))) 188 goto fail; 189 if (params.tid2 != NULL && 190 (error = copyout(&lp->lwp_tid, params.tid2, sizeof(lp->lwp_tid)))) 191 goto fail; 192 193 /* 194 * Now schedule the new lwp. 195 */ 196 p->p_usched->resetpriority(lp); 197 crit_enter(); 198 lp->lwp_stat = LSRUN; 199 p->p_usched->setrunqueue(lp); 200 crit_exit(); 201 202 return (0); 203 204 fail: 205 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp); 206 --p->p_nthreads; 207 /* lwp_dispose expects an exited lwp, and a held proc */ 208 lp->lwp_flag |= LWP_WEXIT; 209 lp->lwp_thread->td_flags |= TDF_EXITING; 210 PHOLD(p); 211 lwp_dispose(lp); 212 fail2: 213 return (error); 214 } 215 216 int nprocs = 1; /* process 0 */ 217 218 int 219 fork1(struct lwp *lp1, int flags, struct proc **procp) 220 { 221 struct proc *p1 = lp1->lwp_proc; 222 struct proc *p2, *pptr; 223 struct pgrp *pgrp; 224 uid_t uid; 225 int ok, error; 226 static int curfail = 0; 227 static struct timeval lastfail; 228 struct forklist *ep; 229 struct filedesc_to_leader *fdtol; 230 231 if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG)) 232 return (EINVAL); 233 234 /* 235 * Here we don't create a new process, but we divorce 236 * certain parts of a process from itself. 237 */ 238 if ((flags & RFPROC) == 0) { 239 /* 240 * This kind of stunt does not work anymore if 241 * there are native threads (lwps) running 242 */ 243 if (p1->p_nthreads != 1) 244 return (EINVAL); 245 246 vm_fork(p1, 0, flags); 247 248 /* 249 * Close all file descriptors. 250 */ 251 if (flags & RFCFDG) { 252 struct filedesc *fdtmp; 253 fdtmp = fdinit(p1); 254 fdfree(p1); 255 p1->p_fd = fdtmp; 256 } 257 258 /* 259 * Unshare file descriptors (from parent.) 260 */ 261 if (flags & RFFDG) { 262 if (p1->p_fd->fd_refcnt > 1) { 263 struct filedesc *newfd; 264 newfd = fdcopy(p1); 265 fdfree(p1); 266 p1->p_fd = newfd; 267 } 268 } 269 *procp = NULL; 270 return (0); 271 } 272 273 /* 274 * Interlock against process group signal delivery. If signals 275 * are pending after the interlock is obtained we have to restart 276 * the system call to process the signals. If we don't the child 277 * can miss a pgsignal (such as ^C) sent during the fork. 278 * 279 * We can't use CURSIG() here because it will process any STOPs 280 * and cause the process group lock to be held indefinitely. If 281 * a STOP occurs, the fork will be restarted after the CONT. 282 */ 283 error = 0; 284 pgrp = NULL; 285 if ((flags & RFPGLOCK) && (pgrp = p1->p_pgrp) != NULL) { 286 lockmgr(&pgrp->pg_lock, LK_SHARED); 287 if (CURSIGNB(lp1)) { 288 error = ERESTART; 289 goto done; 290 } 291 } 292 293 /* 294 * Although process entries are dynamically created, we still keep 295 * a global limit on the maximum number we will create. Don't allow 296 * a nonprivileged user to use the last ten processes; don't let root 297 * exceed the limit. The variable nprocs is the current number of 298 * processes, maxproc is the limit. 299 */ 300 uid = p1->p_ucred->cr_ruid; 301 if ((nprocs >= maxproc - 10 && uid != 0) || nprocs >= maxproc) { 302 if (ppsratecheck(&lastfail, &curfail, 1)) 303 kprintf("maxproc limit exceeded by uid %d, please " 304 "see tuning(7) and login.conf(5).\n", uid); 305 tsleep(&forksleep, 0, "fork", hz / 2); 306 error = EAGAIN; 307 goto done; 308 } 309 /* 310 * Increment the nprocs resource before blocking can occur. There 311 * are hard-limits as to the number of processes that can run. 312 */ 313 nprocs++; 314 315 /* 316 * Increment the count of procs running with this uid. Don't allow 317 * a nonprivileged user to exceed their current limit. 318 */ 319 ok = chgproccnt(p1->p_ucred->cr_ruidinfo, 1, 320 (uid != 0) ? p1->p_rlimit[RLIMIT_NPROC].rlim_cur : 0); 321 if (!ok) { 322 /* 323 * Back out the process count 324 */ 325 nprocs--; 326 if (ppsratecheck(&lastfail, &curfail, 1)) 327 kprintf("maxproc limit exceeded by uid %d, please " 328 "see tuning(7) and login.conf(5).\n", uid); 329 tsleep(&forksleep, 0, "fork", hz / 2); 330 error = EAGAIN; 331 goto done; 332 } 333 334 /* Allocate new proc. */ 335 p2 = kmalloc(sizeof(struct proc), M_PROC, M_WAITOK|M_ZERO); 336 337 /* 338 * Setup linkage for kernel based threading XXX lwp 339 */ 340 if (flags & RFTHREAD) { 341 p2->p_peers = p1->p_peers; 342 p1->p_peers = p2; 343 p2->p_leader = p1->p_leader; 344 } else { 345 p2->p_leader = p2; 346 } 347 348 RB_INIT(&p2->p_lwp_tree); 349 p2->p_lasttid = -1; /* first tid will be 0 */ 350 351 /* 352 * Setting the state to SIDL protects the partially initialized 353 * process once it starts getting hooked into the rest of the system. 354 */ 355 p2->p_stat = SIDL; 356 proc_add_allproc(p2); 357 358 /* 359 * Make a proc table entry for the new process. 360 * The whole structure was zeroed above, so copy the section that is 361 * copied directly from the parent. 362 */ 363 bcopy(&p1->p_startcopy, &p2->p_startcopy, 364 (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy)); 365 366 /* 367 * Duplicate sub-structures as needed. 368 * Increase reference counts on shared objects. 369 */ 370 if (p1->p_flag & P_PROFIL) 371 startprofclock(p2); 372 p2->p_ucred = crhold(p1->p_ucred); 373 374 if (jailed(p2->p_ucred)) 375 p2->p_flag |= P_JAILED; 376 377 if (p2->p_args) 378 p2->p_args->ar_ref++; 379 380 p2->p_usched = p1->p_usched; 381 382 if (flags & RFSIGSHARE) { 383 p2->p_sigacts = p1->p_sigacts; 384 p2->p_sigacts->ps_refcnt++; 385 } else { 386 p2->p_sigacts = (struct sigacts *)kmalloc(sizeof(*p2->p_sigacts), 387 M_SUBPROC, M_WAITOK); 388 bcopy(p1->p_sigacts, p2->p_sigacts, sizeof(*p2->p_sigacts)); 389 p2->p_sigacts->ps_refcnt = 1; 390 } 391 if (flags & RFLINUXTHPN) 392 p2->p_sigparent = SIGUSR1; 393 else 394 p2->p_sigparent = SIGCHLD; 395 396 /* bump references to the text vnode (for procfs) */ 397 p2->p_textvp = p1->p_textvp; 398 if (p2->p_textvp) 399 vref(p2->p_textvp); 400 401 /* 402 * Handle file descriptors 403 */ 404 if (flags & RFCFDG) { 405 p2->p_fd = fdinit(p1); 406 fdtol = NULL; 407 } else if (flags & RFFDG) { 408 p2->p_fd = fdcopy(p1); 409 fdtol = NULL; 410 } else { 411 p2->p_fd = fdshare(p1); 412 if (p1->p_fdtol == NULL) 413 p1->p_fdtol = 414 filedesc_to_leader_alloc(NULL, 415 p1->p_leader); 416 if ((flags & RFTHREAD) != 0) { 417 /* 418 * Shared file descriptor table and 419 * shared process leaders. 420 */ 421 fdtol = p1->p_fdtol; 422 fdtol->fdl_refcount++; 423 } else { 424 /* 425 * Shared file descriptor table, and 426 * different process leaders 427 */ 428 fdtol = filedesc_to_leader_alloc(p1->p_fdtol, p2); 429 } 430 } 431 p2->p_fdtol = fdtol; 432 p2->p_limit = plimit_fork(p1->p_limit); 433 434 /* 435 * Preserve some more flags in subprocess. P_PROFIL has already 436 * been preserved. 437 */ 438 p2->p_flag |= p1->p_flag & P_SUGID; 439 if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT) 440 p2->p_flag |= P_CONTROLT; 441 if (flags & RFPPWAIT) 442 p2->p_flag |= P_PPWAIT; 443 444 /* 445 * Inherit the virtual kernel structure (allows a virtual kernel 446 * to fork to simulate multiple cpus). 447 */ 448 if (p1->p_vkernel) 449 vkernel_inherit(p1, p2); 450 451 /* 452 * Once we are on a pglist we may receive signals. XXX we might 453 * race a ^C being sent to the process group by not receiving it 454 * at all prior to this line. 455 */ 456 LIST_INSERT_AFTER(p1, p2, p_pglist); 457 458 /* 459 * Attach the new process to its parent. 460 * 461 * If RFNOWAIT is set, the newly created process becomes a child 462 * of init. This effectively disassociates the child from the 463 * parent. 464 */ 465 if (flags & RFNOWAIT) 466 pptr = initproc; 467 else 468 pptr = p1; 469 p2->p_pptr = pptr; 470 LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling); 471 LIST_INIT(&p2->p_children); 472 varsymset_init(&p2->p_varsymset, &p1->p_varsymset); 473 callout_init(&p2->p_ithandle); 474 475 #ifdef KTRACE 476 /* 477 * Copy traceflag and tracefile if enabled. If not inherited, 478 * these were zeroed above but we still could have a trace race 479 * so make sure p2's p_tracenode is NULL. 480 */ 481 if ((p1->p_traceflag & KTRFAC_INHERIT) && p2->p_tracenode == NULL) { 482 p2->p_traceflag = p1->p_traceflag; 483 p2->p_tracenode = ktrinherit(p1->p_tracenode); 484 } 485 #endif 486 487 /* 488 * This begins the section where we must prevent the parent 489 * from being swapped. 490 * 491 * Gets PRELE'd in the caller in start_forked_proc(). 492 */ 493 PHOLD(p1); 494 495 vm_fork(p1, p2, flags); 496 497 /* 498 * Create the first lwp associated with the new proc. 499 * It will return via a different execution path later, directly 500 * into userland, after it was put on the runq by 501 * start_forked_proc(). 502 */ 503 lwp_fork(lp1, p2, flags); 504 505 if (flags == (RFFDG | RFPROC)) { 506 mycpu->gd_cnt.v_forks++; 507 mycpu->gd_cnt.v_forkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize; 508 } else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) { 509 mycpu->gd_cnt.v_vforks++; 510 mycpu->gd_cnt.v_vforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize; 511 } else if (p1 == &proc0) { 512 mycpu->gd_cnt.v_kthreads++; 513 mycpu->gd_cnt.v_kthreadpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize; 514 } else { 515 mycpu->gd_cnt.v_rforks++; 516 mycpu->gd_cnt.v_rforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize; 517 } 518 519 /* 520 * Both processes are set up, now check if any loadable modules want 521 * to adjust anything. 522 * What if they have an error? XXX 523 */ 524 TAILQ_FOREACH(ep, &fork_list, next) { 525 (*ep->function)(p1, p2, flags); 526 } 527 528 /* 529 * Set the start time. Note that the process is not runnable. The 530 * caller is responsible for making it runnable. 531 */ 532 microtime(&p2->p_start); 533 p2->p_acflag = AFORK; 534 535 /* 536 * tell any interested parties about the new process 537 */ 538 KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid); 539 540 /* 541 * Return child proc pointer to parent. 542 */ 543 *procp = p2; 544 done: 545 if (pgrp) 546 lockmgr(&pgrp->pg_lock, LK_RELEASE); 547 return (error); 548 } 549 550 static struct lwp * 551 lwp_fork(struct lwp *origlp, struct proc *destproc, int flags) 552 { 553 struct lwp *lp; 554 struct thread *td; 555 556 lp = zalloc(lwp_zone); 557 bzero(lp, sizeof(*lp)); 558 559 lp->lwp_proc = destproc; 560 lp->lwp_vmspace = destproc->p_vmspace; 561 lp->lwp_stat = LSRUN; 562 bcopy(&origlp->lwp_startcopy, &lp->lwp_startcopy, 563 (unsigned) ((caddr_t)&lp->lwp_endcopy - 564 (caddr_t)&lp->lwp_startcopy)); 565 lp->lwp_flag |= origlp->lwp_flag & LWP_ALTSTACK; 566 /* 567 * Set cpbase to the last timeout that occured (not the upcoming 568 * timeout). 569 * 570 * A critical section is required since a timer IPI can update 571 * scheduler specific data. 572 */ 573 crit_enter(); 574 lp->lwp_cpbase = mycpu->gd_schedclock.time - 575 mycpu->gd_schedclock.periodic; 576 destproc->p_usched->heuristic_forking(origlp, lp); 577 crit_exit(); 578 lp->lwp_cpumask &= usched_mastermask; 579 580 /* 581 * Assign a TID to the lp. Loop until the insert succeeds (returns 582 * NULL). 583 */ 584 lp->lwp_tid = destproc->p_lasttid; 585 do { 586 if (++lp->lwp_tid < 0) 587 lp->lwp_tid = 1; 588 } while (lwp_rb_tree_RB_INSERT(&destproc->p_lwp_tree, lp) != NULL); 589 destproc->p_lasttid = lp->lwp_tid; 590 destproc->p_nthreads++; 591 592 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1, 0); 593 lp->lwp_thread = td; 594 td->td_proc = destproc; 595 td->td_lwp = lp; 596 td->td_switch = cpu_heavy_switch; 597 #ifdef SMP 598 KKASSERT(td->td_mpcount == 1); 599 #endif 600 lwkt_setpri(td, TDPRI_KERN_USER); 601 lwkt_set_comm(td, "%s", destproc->p_comm); 602 603 /* 604 * cpu_fork will copy and update the pcb, set up the kernel stack, 605 * and make the child ready to run. 606 */ 607 cpu_fork(origlp, lp, flags); 608 caps_fork(origlp->lwp_thread, lp->lwp_thread); 609 610 return (lp); 611 } 612 613 /* 614 * The next two functionms are general routines to handle adding/deleting 615 * items on the fork callout list. 616 * 617 * at_fork(): 618 * Take the arguments given and put them onto the fork callout list, 619 * However first make sure that it's not already there. 620 * Returns 0 on success or a standard error number. 621 */ 622 int 623 at_fork(forklist_fn function) 624 { 625 struct forklist *ep; 626 627 #ifdef INVARIANTS 628 /* let the programmer know if he's been stupid */ 629 if (rm_at_fork(function)) { 630 kprintf("WARNING: fork callout entry (%p) already present\n", 631 function); 632 } 633 #endif 634 ep = kmalloc(sizeof(*ep), M_ATFORK, M_WAITOK|M_ZERO); 635 ep->function = function; 636 TAILQ_INSERT_TAIL(&fork_list, ep, next); 637 return (0); 638 } 639 640 /* 641 * Scan the exit callout list for the given item and remove it.. 642 * Returns the number of items removed (0 or 1) 643 */ 644 int 645 rm_at_fork(forklist_fn function) 646 { 647 struct forklist *ep; 648 649 TAILQ_FOREACH(ep, &fork_list, next) { 650 if (ep->function == function) { 651 TAILQ_REMOVE(&fork_list, ep, next); 652 kfree(ep, M_ATFORK); 653 return(1); 654 } 655 } 656 return (0); 657 } 658 659 /* 660 * Add a forked process to the run queue after any remaining setup, such 661 * as setting the fork handler, has been completed. 662 */ 663 void 664 start_forked_proc(struct lwp *lp1, struct proc *p2) 665 { 666 struct lwp *lp2 = ONLY_LWP_IN_PROC(p2); 667 668 /* 669 * Move from SIDL to RUN queue, and activate the process's thread. 670 * Activation of the thread effectively makes the process "a" 671 * current process, so we do not setrunqueue(). 672 * 673 * YYY setrunqueue works here but we should clean up the trampoline 674 * code so we just schedule the LWKT thread and let the trampoline 675 * deal with the userland scheduler on return to userland. 676 */ 677 KASSERT(p2->p_stat == SIDL, 678 ("cannot start forked process, bad status: %p", p2)); 679 p2->p_usched->resetpriority(lp2); 680 crit_enter(); 681 p2->p_stat = SACTIVE; 682 lp2->lwp_stat = LSRUN; 683 p2->p_usched->setrunqueue(lp2); 684 crit_exit(); 685 686 /* 687 * Now can be swapped. 688 */ 689 PRELE(lp1->lwp_proc); 690 691 /* 692 * Preserve synchronization semantics of vfork. If waiting for 693 * child to exec or exit, set P_PPWAIT on child, and sleep on our 694 * proc (in case of exit). 695 */ 696 while (p2->p_flag & P_PPWAIT) 697 tsleep(lp1->lwp_proc, 0, "ppwait", 0); 698 } 699