Fix a broken array lookup in the old 4.3 BSD mmap compatibility code
[dragonfly.git] / sys / kern / kern_fork.c
CommitLineData
984263bc
MD
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
5bc7cd8d 39 * $FreeBSD: src/sys/kern/kern_fork.c,v 1.72.2.14 2003/06/26 04:15:10 silby Exp $
553ea3c8 40 * $DragonFly: src/sys/kern/kern_fork.c,v 1.43 2005/10/11 09:59:56 corecode Exp $
984263bc
MD
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>
dfc1fc13
EN
57#include <sys/unistd.h>
58#include <sys/jail.h>
59#include <sys/caps.h>
984263bc
MD
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/user.h>
e43a034f 70#include <sys/thread2.h>
984263bc
MD
71
72static 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 */
78struct forklist {
79 forklist_fn function;
80 TAILQ_ENTRY(forklist) next;
81};
82
83TAILQ_HEAD(forklist_head, forklist);
84static struct forklist_head fork_list = TAILQ_HEAD_INITIALIZER(fork_list);
85
984263bc
MD
86int forksleep; /* Place for fork1() to sleep on. */
87
88/* ARGSUSED */
89int
41c20dac 90fork(struct fork_args *uap)
984263bc 91{
553ea3c8 92 struct lwp *lp = curthread->td_lwp;
984263bc 93 struct proc *p2;
41c20dac 94 int error;
984263bc 95
553ea3c8 96 error = fork1(lp, RFFDG | RFPROC, &p2);
984263bc 97 if (error == 0) {
553ea3c8 98 start_forked_proc(lp, p2);
c7114eea
MD
99 uap->sysmsg_fds[0] = p2->p_pid;
100 uap->sysmsg_fds[1] = 0;
984263bc
MD
101 }
102 return error;
103}
104
105/* ARGSUSED */
106int
41c20dac 107vfork(struct vfork_args *uap)
984263bc 108{
553ea3c8 109 struct lwp *lp = curthread->td_lwp;
984263bc 110 struct proc *p2;
41c20dac 111 int error;
984263bc 112
553ea3c8 113 error = fork1(lp, RFFDG | RFPROC | RFPPWAIT | RFMEM, &p2);
984263bc 114 if (error == 0) {
553ea3c8 115 start_forked_proc(lp, p2);
c7114eea
MD
116 uap->sysmsg_fds[0] = p2->p_pid;
117 uap->sysmsg_fds[1] = 0;
984263bc
MD
118 }
119 return error;
120}
121
f61c1ff1
MD
122/*
123 * Handle rforks. An rfork may (1) operate on the current process without
124 * creating a new, (2) create a new process that shared the current process's
125 * vmspace, signals, and/or descriptors, or (3) create a new process that does
126 * not share these things (normal fork).
127 *
128 * Note that we only call start_forked_proc() if a new process is actually
129 * created.
130 *
131 * rfork { int flags }
132 */
984263bc 133int
41c20dac 134rfork(struct rfork_args *uap)
984263bc 135{
553ea3c8 136 struct lwp *lp = curthread->td_lwp;
984263bc 137 struct proc *p2;
41c20dac 138 int error;
984263bc 139
6654fbcb
MD
140 if ((uap->flags & RFKERNELONLY) != 0)
141 return (EINVAL);
142
553ea3c8 143 error = fork1(lp, uap->flags, &p2);
984263bc 144 if (error == 0) {
f61c1ff1 145 if (p2)
553ea3c8 146 start_forked_proc(lp, p2);
c7114eea
MD
147 uap->sysmsg_fds[0] = p2 ? p2->p_pid : 0;
148 uap->sysmsg_fds[1] = 0;
984263bc
MD
149 }
150 return error;
151}
152
153
154int nprocs = 1; /* process 0 */
155static int nextpid = 0;
156
157/*
158 * Random component to nextpid generation. We mix in a random factor to make
159 * it a little harder to predict. We sanity check the modulus value to avoid
160 * doing it in critical paths. Don't let it be too small or we pointlessly
161 * waste randomness entropy, and don't let it be impossibly large. Using a
162 * modulus that is too big causes a LOT more process table scans and slows
163 * down fork processing as the pidchecked caching is defeated.
164 */
165static int randompid = 0;
166
167static int
168sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
169{
170 int error, pid;
171
172 pid = randompid;
173 error = sysctl_handle_int(oidp, &pid, 0, req);
174 if (error || !req->newptr)
175 return (error);
176 if (pid < 0 || pid > PID_MAX - 100) /* out of range */
177 pid = PID_MAX - 100;
178 else if (pid < 2) /* NOP */
179 pid = 0;
180 else if (pid < 100) /* Make it reasonable */
181 pid = 100;
182 randompid = pid;
183 return (error);
184}
185
186SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
187 0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
188
189int
553ea3c8 190fork1(struct lwp *lp1, int flags, struct proc **procp)
984263bc 191{
553ea3c8 192 struct proc *p1 = lp1->lwp_proc;
984263bc 193 struct proc *p2, *pptr;
553ea3c8 194 struct lwp *lp2;
984263bc
MD
195 uid_t uid;
196 struct proc *newproc;
197 int ok;
5bc7cd8d
HP
198 static int curfail = 0, pidchecked = 0;
199 static struct timeval lastfail;
984263bc
MD
200 struct forklist *ep;
201 struct filedesc_to_leader *fdtol;
202
203 if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
204 return (EINVAL);
205
206 /*
207 * Here we don't create a new process, but we divorce
208 * certain parts of a process from itself.
209 */
210 if ((flags & RFPROC) == 0) {
211
212 vm_fork(p1, 0, flags);
213
214 /*
215 * Close all file descriptors.
216 */
217 if (flags & RFCFDG) {
218 struct filedesc *fdtmp;
219 fdtmp = fdinit(p1);
220 fdfree(p1);
221 p1->p_fd = fdtmp;
222 }
223
224 /*
225 * Unshare file descriptors (from parent.)
226 */
227 if (flags & RFFDG) {
228 if (p1->p_fd->fd_refcnt > 1) {
229 struct filedesc *newfd;
230 newfd = fdcopy(p1);
231 fdfree(p1);
232 p1->p_fd = newfd;
233 }
234 }
235 *procp = NULL;
236 return (0);
237 }
238
239 /*
240 * Although process entries are dynamically created, we still keep
241 * a global limit on the maximum number we will create. Don't allow
242 * a nonprivileged user to use the last ten processes; don't let root
243 * exceed the limit. The variable nprocs is the current number of
244 * processes, maxproc is the limit.
245 */
41c20dac 246 uid = p1->p_ucred->cr_ruid;
984263bc 247 if ((nprocs >= maxproc - 10 && uid != 0) || nprocs >= maxproc) {
5bc7cd8d
HP
248 if (ppsratecheck(&lastfail, &curfail, 1))
249 printf("maxproc limit exceeded by uid %d, please "
250 "see tuning(7) and login.conf(5).\n", uid);
377d4740 251 tsleep(&forksleep, 0, "fork", hz / 2);
984263bc
MD
252 return (EAGAIN);
253 }
254 /*
255 * Increment the nprocs resource before blocking can occur. There
256 * are hard-limits as to the number of processes that can run.
257 */
258 nprocs++;
259
260 /*
261 * Increment the count of procs running with this uid. Don't allow
262 * a nonprivileged user to exceed their current limit.
263 */
41c20dac 264 ok = chgproccnt(p1->p_ucred->cr_ruidinfo, 1,
984263bc
MD
265 (uid != 0) ? p1->p_rlimit[RLIMIT_NPROC].rlim_cur : 0);
266 if (!ok) {
267 /*
268 * Back out the process count
269 */
270 nprocs--;
5bc7cd8d
HP
271 if (ppsratecheck(&lastfail, &curfail, 1))
272 printf("maxproc limit exceeded by uid %d, please "
273 "see tuning(7) and login.conf(5).\n", uid);
377d4740 274 tsleep(&forksleep, 0, "fork", hz / 2);
984263bc
MD
275 return (EAGAIN);
276 }
277
278 /* Allocate new proc. */
279 newproc = zalloc(proc_zone);
280
281 /*
ef09c3ed 282 * Setup linkage for kernel based threading XXX lwp
984263bc 283 */
303c76d5 284 if ((flags & RFTHREAD) != 0) {
984263bc
MD
285 newproc->p_peers = p1->p_peers;
286 p1->p_peers = newproc;
287 newproc->p_leader = p1->p_leader;
288 } else {
289 newproc->p_peers = 0;
290 newproc->p_leader = newproc;
291 }
292
293 newproc->p_wakeup = 0;
984263bc 294 newproc->p_vmspace = NULL;
81eea9f4 295 TAILQ_INIT(&newproc->p_lwp.lwp_sysmsgq);
ef09c3ed
SS
296 LIST_INIT(&newproc->p_lwps);
297
298 /* XXX lwp */
553ea3c8
SS
299 lp2 = &newproc->p_lwp;
300 lp2->lwp_proc = newproc;
301 lp2->lwp_tid = 0;
302 LIST_INSERT_HEAD(&newproc->p_lwps, lp2, lwp_list);
ac33e87f 303 newproc->p_nthreads = 1;
984263bc
MD
304
305 /*
306 * Find an unused process ID. We remember a range of unused IDs
307 * ready to use (from nextpid+1 through pidchecked-1).
308 */
309 nextpid++;
310 if (randompid)
311 nextpid += arc4random() % randompid;
312retry:
313 /*
314 * If the process ID prototype has wrapped around,
315 * restart somewhat above 0, as the low-numbered procs
316 * tend to include daemons that don't exit.
317 */
318 if (nextpid >= PID_MAX) {
319 nextpid = nextpid % PID_MAX;
320 if (nextpid < 100)
321 nextpid += 100;
322 pidchecked = 0;
323 }
324 if (nextpid >= pidchecked) {
325 int doingzomb = 0;
326
327 pidchecked = PID_MAX;
328 /*
329 * Scan the active and zombie procs to check whether this pid
330 * is in use. Remember the lowest pid that's greater
331 * than nextpid, so we can avoid checking for a while.
332 */
333 p2 = LIST_FIRST(&allproc);
334again:
335 for (; p2 != 0; p2 = LIST_NEXT(p2, p_list)) {
336 while (p2->p_pid == nextpid ||
337 p2->p_pgrp->pg_id == nextpid ||
338 p2->p_session->s_sid == nextpid) {
339 nextpid++;
340 if (nextpid >= pidchecked)
341 goto retry;
342 }
343 if (p2->p_pid > nextpid && pidchecked > p2->p_pid)
344 pidchecked = p2->p_pid;
345 if (p2->p_pgrp->pg_id > nextpid &&
346 pidchecked > p2->p_pgrp->pg_id)
347 pidchecked = p2->p_pgrp->pg_id;
348 if (p2->p_session->s_sid > nextpid &&
349 pidchecked > p2->p_session->s_sid)
350 pidchecked = p2->p_session->s_sid;
351 }
352 if (!doingzomb) {
353 doingzomb = 1;
354 p2 = LIST_FIRST(&zombproc);
355 goto again;
356 }
357 }
358
359 p2 = newproc;
360 p2->p_stat = SIDL; /* protect against others */
361 p2->p_pid = nextpid;
362 LIST_INSERT_HEAD(&allproc, p2, p_list);
363 LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
364
365 /*
366 * Make a proc table entry for the new process.
367 * Start by zeroing the section of proc that is zero-initialized,
368 * then copy the section that is copied directly from the parent.
369 */
370 bzero(&p2->p_startzero,
371 (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero));
553ea3c8
SS
372 bzero(&lp2->lwp_startzero,
373 (unsigned) ((caddr_t)&lp2->lwp_endzero -
374 (caddr_t)&lp2->lwp_startzero));
984263bc
MD
375 bcopy(&p1->p_startcopy, &p2->p_startcopy,
376 (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
553ea3c8
SS
377 bcopy(&p1->p_lwp.lwp_startcopy, &lp2->lwp_startcopy,
378 (unsigned) ((caddr_t)&lp2->lwp_endcopy -
379 (caddr_t)&lp2->lwp_startcopy));
984263bc
MD
380
381 p2->p_aioinfo = NULL;
382
383 /*
384 * Duplicate sub-structures as needed.
385 * Increase reference counts on shared objects.
386 * The p_stats and p_sigacts substructs are set in vm_fork.
387 */
8ec60c3f 388 p2->p_flag = P_INMEM;
984263bc
MD
389 if (p1->p_flag & P_PROFIL)
390 startprofclock(p2);
dadab5e9 391 p2->p_ucred = crhold(p1->p_ucred);
984263bc 392
b40e316c 393 if (jailed(p2->p_ucred))
984263bc 394 p2->p_flag |= P_JAILED;
984263bc
MD
395
396 if (p2->p_args)
397 p2->p_args->ar_ref++;
398
399 if (flags & RFSIGSHARE) {
400 p2->p_procsig = p1->p_procsig;
401 p2->p_procsig->ps_refcnt++;
402 if (p1->p_sigacts == &p1->p_addr->u_sigacts) {
403 struct sigacts *newsigacts;
984263bc
MD
404
405 /* Create the shared sigacts structure */
406 MALLOC(newsigacts, struct sigacts *,
407 sizeof(struct sigacts), M_SUBPROC, M_WAITOK);
e43a034f 408 crit_enter();
984263bc
MD
409 /*
410 * Set p_sigacts to the new shared structure.
411 * Note that this is updating p1->p_sigacts at the
412 * same time, since p_sigacts is just a pointer to
413 * the shared p_procsig->ps_sigacts.
414 */
415 p2->p_sigacts = newsigacts;
416 bcopy(&p1->p_addr->u_sigacts, p2->p_sigacts,
417 sizeof(*p2->p_sigacts));
418 *p2->p_sigacts = p1->p_addr->u_sigacts;
e43a034f 419 crit_exit();
984263bc
MD
420 }
421 } else {
422 MALLOC(p2->p_procsig, struct procsig *, sizeof(struct procsig),
423 M_SUBPROC, M_WAITOK);
424 bcopy(p1->p_procsig, p2->p_procsig, sizeof(*p2->p_procsig));
425 p2->p_procsig->ps_refcnt = 1;
426 p2->p_sigacts = NULL; /* finished in vm_fork() */
427 }
428 if (flags & RFLINUXTHPN)
429 p2->p_sigparent = SIGUSR1;
430 else
431 p2->p_sigparent = SIGCHLD;
432
433 /* bump references to the text vnode (for procfs) */
434 p2->p_textvp = p1->p_textvp;
435 if (p2->p_textvp)
597aea93 436 vref(p2->p_textvp);
984263bc
MD
437
438 if (flags & RFCFDG) {
439 p2->p_fd = fdinit(p1);
440 fdtol = NULL;
441 } else if (flags & RFFDG) {
442 p2->p_fd = fdcopy(p1);
443 fdtol = NULL;
444 } else {
445 p2->p_fd = fdshare(p1);
446 if (p1->p_fdtol == NULL)
447 p1->p_fdtol =
448 filedesc_to_leader_alloc(NULL,
449 p1->p_leader);
450 if ((flags & RFTHREAD) != 0) {
451 /*
452 * Shared file descriptor table and
453 * shared process leaders.
454 */
455 fdtol = p1->p_fdtol;
456 fdtol->fdl_refcount++;
457 } else {
458 /*
459 * Shared file descriptor table, and
460 * different process leaders
461 */
98a7f915 462 fdtol = filedesc_to_leader_alloc(p1->p_fdtol, p2);
984263bc
MD
463 }
464 }
465 p2->p_fdtol = fdtol;
466
467 /*
468 * If p_limit is still copy-on-write, bump refcnt,
469 * otherwise get a copy that won't be modified.
470 * (If PL_SHAREMOD is clear, the structure is shared
471 * copy-on-write.)
472 */
303c76d5 473 if (p1->p_limit->p_lflags & PL_SHAREMOD) {
984263bc 474 p2->p_limit = limcopy(p1->p_limit);
303c76d5 475 } else {
984263bc
MD
476 p2->p_limit = p1->p_limit;
477 p2->p_limit->p_refcnt++;
478 }
479
480 /*
481 * Preserve some more flags in subprocess. P_PROFIL has already
482 * been preserved.
483 */
484 p2->p_flag |= p1->p_flag & (P_SUGID | P_ALTSTACK);
485 if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
486 p2->p_flag |= P_CONTROLT;
487 if (flags & RFPPWAIT)
488 p2->p_flag |= P_PPWAIT;
489
5fd012e0
MD
490 /*
491 * Once we are on a pglist we may receive signals. XXX we might
492 * race a ^C being sent to the process group by not receiving it
493 * at all prior to this line.
494 */
984263bc
MD
495 LIST_INSERT_AFTER(p1, p2, p_pglist);
496
497 /*
498 * Attach the new process to its parent.
499 *
500 * If RFNOWAIT is set, the newly created process becomes a child
501 * of init. This effectively disassociates the child from the
502 * parent.
503 */
504 if (flags & RFNOWAIT)
505 pptr = initproc;
506 else
507 pptr = p1;
508 p2->p_pptr = pptr;
509 LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling);
510 LIST_INIT(&p2->p_children);
98a7f915 511 varsymset_init(&p2->p_varsymset, &p1->p_varsymset);
8fbf9130 512 callout_init(&p2->p_ithandle);
984263bc
MD
513
514#ifdef KTRACE
515 /*
516 * Copy traceflag and tracefile if enabled. If not inherited,
517 * these were zeroed above but we still could have a trace race
518 * so make sure p2's p_tracep is NULL.
519 */
520 if ((p1->p_traceflag & KTRFAC_INHERIT) && p2->p_tracep == NULL) {
521 p2->p_traceflag = p1->p_traceflag;
522 if ((p2->p_tracep = p1->p_tracep) != NULL)
597aea93 523 vref(p2->p_tracep);
984263bc
MD
524 }
525#endif
526
527 /*
352f5709 528 * Inherit the scheduler and initialize scheduler-related fields.
dcc99b62
MD
529 * Set cpbase to the last timeout that occured (not the upcoming
530 * timeout).
a77ac49d
MD
531 */
532 p2->p_usched = p1->p_usched;
553ea3c8 533 lp2->lwp_cpbase = mycpu->gd_schedclock.time -
dcc99b62 534 mycpu->gd_schedclock.periodic;
553ea3c8 535 p2->p_usched->heuristic_forking(&p1->p_lwp, lp2);
a77ac49d 536
984263bc
MD
537 /*
538 * This begins the section where we must prevent the parent
539 * from being swapped.
540 */
541 PHOLD(p1);
542
543 /*
544 * Finish creating the child process. It will return via a different
545 * execution path later. (ie: directly into user mode)
546 */
547 vm_fork(p1, p2, flags);
e30f9e2c 548 caps_fork(p1, p2, flags);
984263bc
MD
549
550 if (flags == (RFFDG | RFPROC)) {
12e4aaff
MD
551 mycpu->gd_cnt.v_forks++;
552 mycpu->gd_cnt.v_forkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 553 } else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) {
12e4aaff
MD
554 mycpu->gd_cnt.v_vforks++;
555 mycpu->gd_cnt.v_vforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 556 } else if (p1 == &proc0) {
12e4aaff
MD
557 mycpu->gd_cnt.v_kthreads++;
558 mycpu->gd_cnt.v_kthreadpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 559 } else {
12e4aaff
MD
560 mycpu->gd_cnt.v_rforks++;
561 mycpu->gd_cnt.v_rforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc
MD
562 }
563
564 /*
565 * Both processes are set up, now check if any loadable modules want
566 * to adjust anything.
567 * What if they have an error? XXX
568 */
569 TAILQ_FOREACH(ep, &fork_list, next) {
570 (*ep->function)(p1, p2, flags);
571 }
572
573 /*
a77ac49d
MD
574 * Set the start time. Note that the process is not runnable. The
575 * caller is responsible for making it runnable.
984263bc 576 */
d9fa5f67 577 microtime(&p2->p_start);
984263bc 578 p2->p_acflag = AFORK;
984263bc
MD
579
580 /*
581 * tell any interested parties about the new process
582 */
583 KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid);
584
984263bc
MD
585 /*
586 * Return child proc pointer to parent.
587 */
588 *procp = p2;
589 return (0);
590}
591
592/*
593 * The next two functionms are general routines to handle adding/deleting
594 * items on the fork callout list.
595 *
596 * at_fork():
597 * Take the arguments given and put them onto the fork callout list,
598 * However first make sure that it's not already there.
599 * Returns 0 on success or a standard error number.
600 */
984263bc 601int
303c76d5 602at_fork(forklist_fn function)
984263bc
MD
603{
604 struct forklist *ep;
605
606#ifdef INVARIANTS
607 /* let the programmer know if he's been stupid */
303c76d5 608 if (rm_at_fork(function)) {
984263bc
MD
609 printf("WARNING: fork callout entry (%p) already present\n",
610 function);
303c76d5 611 }
984263bc 612#endif
679246c3 613 ep = malloc(sizeof(*ep), M_ATFORK, M_WAITOK|M_ZERO);
984263bc
MD
614 ep->function = function;
615 TAILQ_INSERT_TAIL(&fork_list, ep, next);
616 return (0);
617}
618
619/*
620 * Scan the exit callout list for the given item and remove it..
621 * Returns the number of items removed (0 or 1)
622 */
984263bc 623int
303c76d5 624rm_at_fork(forklist_fn function)
984263bc
MD
625{
626 struct forklist *ep;
627
628 TAILQ_FOREACH(ep, &fork_list, next) {
629 if (ep->function == function) {
630 TAILQ_REMOVE(&fork_list, ep, next);
631 free(ep, M_ATFORK);
632 return(1);
633 }
634 }
635 return (0);
636}
7d0bac62
MD
637
638/*
639 * Add a forked process to the run queue after any remaining setup, such
640 * as setting the fork handler, has been completed.
641 */
7d0bac62 642void
553ea3c8 643start_forked_proc(struct lwp *lp1, struct proc *p2)
7d0bac62 644{
553ea3c8
SS
645 struct lwp *lp2;
646
647 KKASSERT(p2 != NULL && p2->p_nthreads == 1);
648
649 lp2 = LIST_FIRST(&p2->p_lwps);
650
7d0bac62 651 /*
26a0694b
MD
652 * Move from SIDL to RUN queue, and activate the process's thread.
653 * Activation of the thread effectively makes the process "a"
654 * current process, so we do not setrunqueue().
8ec60c3f
MD
655 *
656 * YYY setrunqueue works here but we should clean up the trampoline
657 * code so we just schedule the LWKT thread and let the trampoline
658 * deal with the userland scheduler on return to userland.
7d0bac62 659 */
553ea3c8 660 KASSERT(p2->p_stat == SIDL,
7d0bac62 661 ("cannot start forked process, bad status: %p", p2));
553ea3c8 662 p2->p_usched->resetpriority(lp2);
e43a034f 663 crit_enter();
7d0bac62 664 p2->p_stat = SRUN;
553ea3c8 665 p2->p_usched->setrunqueue(lp2);
e43a034f 666 crit_exit();
7d0bac62
MD
667
668 /*
669 * Now can be swapped.
670 */
553ea3c8 671 PRELE(lp1->lwp_proc);
7d0bac62
MD
672
673 /*
674 * Preserve synchronization semantics of vfork. If waiting for
675 * child to exec or exit, set P_PPWAIT on child, and sleep on our
676 * proc (in case of exit).
677 */
678 while (p2->p_flag & P_PPWAIT)
553ea3c8 679 tsleep(lp1->lwp_proc, 0, "ppwait", 0);
7d0bac62 680}