Create 'k' versions of the kernel malloc API.
[dragonfly.git] / sys / kern / kern_fork.c
CommitLineData
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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 $
f9a13fc4 40 * $DragonFly: src/sys/kern/kern_fork.c,v 1.54 2006/06/07 03:02:10 dillon Exp $
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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>
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57#include <sys/unistd.h>
58#include <sys/jail.h>
59#include <sys/caps.h>
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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>
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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
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86int forksleep; /* Place for fork1() to sleep on. */
87
88/* ARGSUSED */
89int
753fd850 90sys_fork(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);
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99 uap->sysmsg_fds[0] = p2->p_pid;
100 uap->sysmsg_fds[1] = 0;
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101 }
102 return error;
103}
104
105/* ARGSUSED */
106int
753fd850 107sys_vfork(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);
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116 uap->sysmsg_fds[0] = p2->p_pid;
117 uap->sysmsg_fds[1] = 0;
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118 }
119 return error;
120}
121
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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
753fd850 134sys_rfork(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
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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);
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147 uap->sysmsg_fds[0] = p2 ? p2->p_pid : 0;
148 uap->sysmsg_fds[1] = 0;
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149 }
150 return error;
151}
152
153
154int nprocs = 1; /* process 0 */
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155
156int
553ea3c8 157fork1(struct lwp *lp1, int flags, struct proc **procp)
984263bc 158{
553ea3c8 159 struct proc *p1 = lp1->lwp_proc;
984263bc 160 struct proc *p2, *pptr;
553ea3c8 161 struct lwp *lp2;
984263bc 162 uid_t uid;
984263bc 163 int ok;
51e64ff2 164 static int curfail = 0;
5bc7cd8d 165 static struct timeval lastfail;
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166 struct forklist *ep;
167 struct filedesc_to_leader *fdtol;
168
169 if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
170 return (EINVAL);
171
172 /*
173 * Here we don't create a new process, but we divorce
174 * certain parts of a process from itself.
175 */
176 if ((flags & RFPROC) == 0) {
177
178 vm_fork(p1, 0, flags);
179
180 /*
181 * Close all file descriptors.
182 */
183 if (flags & RFCFDG) {
184 struct filedesc *fdtmp;
185 fdtmp = fdinit(p1);
186 fdfree(p1);
187 p1->p_fd = fdtmp;
188 }
189
190 /*
191 * Unshare file descriptors (from parent.)
192 */
193 if (flags & RFFDG) {
194 if (p1->p_fd->fd_refcnt > 1) {
195 struct filedesc *newfd;
196 newfd = fdcopy(p1);
197 fdfree(p1);
198 p1->p_fd = newfd;
199 }
200 }
201 *procp = NULL;
202 return (0);
203 }
204
205 /*
206 * Although process entries are dynamically created, we still keep
207 * a global limit on the maximum number we will create. Don't allow
208 * a nonprivileged user to use the last ten processes; don't let root
209 * exceed the limit. The variable nprocs is the current number of
210 * processes, maxproc is the limit.
211 */
41c20dac 212 uid = p1->p_ucred->cr_ruid;
984263bc 213 if ((nprocs >= maxproc - 10 && uid != 0) || nprocs >= maxproc) {
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214 if (ppsratecheck(&lastfail, &curfail, 1))
215 printf("maxproc limit exceeded by uid %d, please "
216 "see tuning(7) and login.conf(5).\n", uid);
377d4740 217 tsleep(&forksleep, 0, "fork", hz / 2);
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218 return (EAGAIN);
219 }
220 /*
221 * Increment the nprocs resource before blocking can occur. There
222 * are hard-limits as to the number of processes that can run.
223 */
224 nprocs++;
225
226 /*
227 * Increment the count of procs running with this uid. Don't allow
228 * a nonprivileged user to exceed their current limit.
229 */
41c20dac 230 ok = chgproccnt(p1->p_ucred->cr_ruidinfo, 1,
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231 (uid != 0) ? p1->p_rlimit[RLIMIT_NPROC].rlim_cur : 0);
232 if (!ok) {
233 /*
234 * Back out the process count
235 */
236 nprocs--;
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237 if (ppsratecheck(&lastfail, &curfail, 1))
238 printf("maxproc limit exceeded by uid %d, please "
239 "see tuning(7) and login.conf(5).\n", uid);
377d4740 240 tsleep(&forksleep, 0, "fork", hz / 2);
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241 return (EAGAIN);
242 }
243
244 /* Allocate new proc. */
51e64ff2 245 p2 = zalloc(proc_zone);
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246
247 /*
ef09c3ed 248 * Setup linkage for kernel based threading XXX lwp
984263bc 249 */
cb74210d 250 if (flags & RFTHREAD) {
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251 p2->p_peers = p1->p_peers;
252 p1->p_peers = p2;
253 p2->p_leader = p1->p_leader;
984263bc 254 } else {
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255 p2->p_peers = NULL;
256 p2->p_leader = p2;
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257 }
258
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259 p2->p_wakeup = 0;
260 p2->p_vmspace = NULL;
261 p2->p_numposixlocks = 0;
262 p2->p_emuldata = NULL;
51e64ff2 263 LIST_INIT(&p2->p_lwps);
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264
265 /* XXX lwp */
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266 lp2 = &p2->p_lwp;
267 lp2->lwp_proc = p2;
553ea3c8 268 lp2->lwp_tid = 0;
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269 LIST_INSERT_HEAD(&p2->p_lwps, lp2, lwp_list);
270 p2->p_nthreads = 1;
271 p2->p_nstopped = 0;
272 p2->p_lasttid = 0;
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273
274 /*
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275 * Setting the state to SIDL protects the partially initialized
276 * process once it starts getting hooked into the rest of the system.
984263bc 277 */
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278 p2->p_stat = SIDL;
279 proc_add_allproc(p2);
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280
281 /*
282 * Make a proc table entry for the new process.
283 * Start by zeroing the section of proc that is zero-initialized,
284 * then copy the section that is copied directly from the parent.
285 */
286 bzero(&p2->p_startzero,
287 (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero));
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288 bzero(&lp2->lwp_startzero,
289 (unsigned) ((caddr_t)&lp2->lwp_endzero -
290 (caddr_t)&lp2->lwp_startzero));
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291 bcopy(&p1->p_startcopy, &p2->p_startcopy,
292 (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
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293 bcopy(&p1->p_lwp.lwp_startcopy, &lp2->lwp_startcopy,
294 (unsigned) ((caddr_t)&lp2->lwp_endcopy -
295 (caddr_t)&lp2->lwp_startcopy));
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296
297 p2->p_aioinfo = NULL;
298
299 /*
300 * Duplicate sub-structures as needed.
301 * Increase reference counts on shared objects.
302 * The p_stats and p_sigacts substructs are set in vm_fork.
3a72e617 303 * p_lock is in the copy area and must be cleared.
984263bc 304 */
344ad853 305 p2->p_flag = 0;
3a72e617 306 p2->p_lock = 0;
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307 if (p1->p_flag & P_PROFIL)
308 startprofclock(p2);
dadab5e9 309 p2->p_ucred = crhold(p1->p_ucred);
984263bc 310
b40e316c 311 if (jailed(p2->p_ucred))
984263bc 312 p2->p_flag |= P_JAILED;
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313
314 if (p2->p_args)
315 p2->p_args->ar_ref++;
316
317 if (flags & RFSIGSHARE) {
318 p2->p_procsig = p1->p_procsig;
319 p2->p_procsig->ps_refcnt++;
320 if (p1->p_sigacts == &p1->p_addr->u_sigacts) {
321 struct sigacts *newsigacts;
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322
323 /* Create the shared sigacts structure */
324 MALLOC(newsigacts, struct sigacts *,
325 sizeof(struct sigacts), M_SUBPROC, M_WAITOK);
e43a034f 326 crit_enter();
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327 /*
328 * Set p_sigacts to the new shared structure.
329 * Note that this is updating p1->p_sigacts at the
330 * same time, since p_sigacts is just a pointer to
331 * the shared p_procsig->ps_sigacts.
332 */
333 p2->p_sigacts = newsigacts;
334 bcopy(&p1->p_addr->u_sigacts, p2->p_sigacts,
335 sizeof(*p2->p_sigacts));
336 *p2->p_sigacts = p1->p_addr->u_sigacts;
e43a034f 337 crit_exit();
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338 }
339 } else {
340 MALLOC(p2->p_procsig, struct procsig *, sizeof(struct procsig),
341 M_SUBPROC, M_WAITOK);
342 bcopy(p1->p_procsig, p2->p_procsig, sizeof(*p2->p_procsig));
343 p2->p_procsig->ps_refcnt = 1;
344 p2->p_sigacts = NULL; /* finished in vm_fork() */
345 }
346 if (flags & RFLINUXTHPN)
347 p2->p_sigparent = SIGUSR1;
348 else
349 p2->p_sigparent = SIGCHLD;
350
351 /* bump references to the text vnode (for procfs) */
352 p2->p_textvp = p1->p_textvp;
353 if (p2->p_textvp)
597aea93 354 vref(p2->p_textvp);
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355
356 if (flags & RFCFDG) {
357 p2->p_fd = fdinit(p1);
358 fdtol = NULL;
359 } else if (flags & RFFDG) {
360 p2->p_fd = fdcopy(p1);
361 fdtol = NULL;
362 } else {
363 p2->p_fd = fdshare(p1);
364 if (p1->p_fdtol == NULL)
365 p1->p_fdtol =
366 filedesc_to_leader_alloc(NULL,
367 p1->p_leader);
368 if ((flags & RFTHREAD) != 0) {
369 /*
370 * Shared file descriptor table and
371 * shared process leaders.
372 */
373 fdtol = p1->p_fdtol;
374 fdtol->fdl_refcount++;
375 } else {
376 /*
377 * Shared file descriptor table, and
378 * different process leaders
379 */
98a7f915 380 fdtol = filedesc_to_leader_alloc(p1->p_fdtol, p2);
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381 }
382 }
383 p2->p_fdtol = fdtol;
c0b8a06d 384 p2->p_limit = plimit_fork(p1->p_limit);
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385
386 /*
387 * Preserve some more flags in subprocess. P_PROFIL has already
388 * been preserved.
389 */
390 p2->p_flag |= p1->p_flag & (P_SUGID | P_ALTSTACK);
391 if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
392 p2->p_flag |= P_CONTROLT;
393 if (flags & RFPPWAIT)
394 p2->p_flag |= P_PPWAIT;
395
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396 /*
397 * Once we are on a pglist we may receive signals. XXX we might
398 * race a ^C being sent to the process group by not receiving it
399 * at all prior to this line.
400 */
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401 LIST_INSERT_AFTER(p1, p2, p_pglist);
402
403 /*
404 * Attach the new process to its parent.
405 *
406 * If RFNOWAIT is set, the newly created process becomes a child
407 * of init. This effectively disassociates the child from the
408 * parent.
409 */
410 if (flags & RFNOWAIT)
411 pptr = initproc;
412 else
413 pptr = p1;
414 p2->p_pptr = pptr;
415 LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling);
416 LIST_INIT(&p2->p_children);
98a7f915 417 varsymset_init(&p2->p_varsymset, &p1->p_varsymset);
8fbf9130 418 callout_init(&p2->p_ithandle);
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419
420#ifdef KTRACE
421 /*
422 * Copy traceflag and tracefile if enabled. If not inherited,
423 * these were zeroed above but we still could have a trace race
29f58392 424 * so make sure p2's p_tracenode is NULL.
984263bc 425 */
29f58392 426 if ((p1->p_traceflag & KTRFAC_INHERIT) && p2->p_tracenode == NULL) {
984263bc 427 p2->p_traceflag = p1->p_traceflag;
29f58392 428 p2->p_tracenode = ktrinherit(p1->p_tracenode);
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429 }
430#endif
431
432 /*
352f5709 433 * Inherit the scheduler and initialize scheduler-related fields.
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434 * Set cpbase to the last timeout that occured (not the upcoming
435 * timeout).
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436 *
437 * A critical section is required since a timer IPI can update
438 * scheduler specific data.
a77ac49d 439 */
50017724 440 crit_enter();
a77ac49d 441 p2->p_usched = p1->p_usched;
553ea3c8 442 lp2->lwp_cpbase = mycpu->gd_schedclock.time -
dcc99b62 443 mycpu->gd_schedclock.periodic;
553ea3c8 444 p2->p_usched->heuristic_forking(&p1->p_lwp, lp2);
50017724 445 crit_exit();
a77ac49d 446
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447 /*
448 * This begins the section where we must prevent the parent
449 * from being swapped.
450 */
451 PHOLD(p1);
452
453 /*
454 * Finish creating the child process. It will return via a different
455 * execution path later. (ie: directly into user mode)
456 */
457 vm_fork(p1, p2, flags);
e30f9e2c 458 caps_fork(p1, p2, flags);
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459
460 if (flags == (RFFDG | RFPROC)) {
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461 mycpu->gd_cnt.v_forks++;
462 mycpu->gd_cnt.v_forkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 463 } else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) {
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464 mycpu->gd_cnt.v_vforks++;
465 mycpu->gd_cnt.v_vforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 466 } else if (p1 == &proc0) {
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467 mycpu->gd_cnt.v_kthreads++;
468 mycpu->gd_cnt.v_kthreadpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
984263bc 469 } else {
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470 mycpu->gd_cnt.v_rforks++;
471 mycpu->gd_cnt.v_rforkpages += p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize;
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472 }
473
474 /*
475 * Both processes are set up, now check if any loadable modules want
476 * to adjust anything.
477 * What if they have an error? XXX
478 */
479 TAILQ_FOREACH(ep, &fork_list, next) {
480 (*ep->function)(p1, p2, flags);
481 }
482
483 /*
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484 * Set the start time. Note that the process is not runnable. The
485 * caller is responsible for making it runnable.
984263bc 486 */
d9fa5f67 487 microtime(&p2->p_start);
984263bc 488 p2->p_acflag = AFORK;
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489
490 /*
491 * tell any interested parties about the new process
492 */
493 KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid);
494
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495 /*
496 * Return child proc pointer to parent.
497 */
498 *procp = p2;
499 return (0);
500}
501
502/*
503 * The next two functionms are general routines to handle adding/deleting
504 * items on the fork callout list.
505 *
506 * at_fork():
507 * Take the arguments given and put them onto the fork callout list,
508 * However first make sure that it's not already there.
509 * Returns 0 on success or a standard error number.
510 */
984263bc 511int
303c76d5 512at_fork(forklist_fn function)
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513{
514 struct forklist *ep;
515
516#ifdef INVARIANTS
517 /* let the programmer know if he's been stupid */
303c76d5 518 if (rm_at_fork(function)) {
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519 printf("WARNING: fork callout entry (%p) already present\n",
520 function);
303c76d5 521 }
984263bc 522#endif
679246c3 523 ep = malloc(sizeof(*ep), M_ATFORK, M_WAITOK|M_ZERO);
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524 ep->function = function;
525 TAILQ_INSERT_TAIL(&fork_list, ep, next);
526 return (0);
527}
528
529/*
530 * Scan the exit callout list for the given item and remove it..
531 * Returns the number of items removed (0 or 1)
532 */
984263bc 533int
303c76d5 534rm_at_fork(forklist_fn function)
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535{
536 struct forklist *ep;
537
538 TAILQ_FOREACH(ep, &fork_list, next) {
539 if (ep->function == function) {
540 TAILQ_REMOVE(&fork_list, ep, next);
541 free(ep, M_ATFORK);
542 return(1);
543 }
544 }
545 return (0);
546}
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547
548/*
549 * Add a forked process to the run queue after any remaining setup, such
550 * as setting the fork handler, has been completed.
551 */
7d0bac62 552void
553ea3c8 553start_forked_proc(struct lwp *lp1, struct proc *p2)
7d0bac62 554{
553ea3c8
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555 struct lwp *lp2;
556
557 KKASSERT(p2 != NULL && p2->p_nthreads == 1);
558
559 lp2 = LIST_FIRST(&p2->p_lwps);
560
7d0bac62 561 /*
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562 * Move from SIDL to RUN queue, and activate the process's thread.
563 * Activation of the thread effectively makes the process "a"
564 * current process, so we do not setrunqueue().
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565 *
566 * YYY setrunqueue works here but we should clean up the trampoline
567 * code so we just schedule the LWKT thread and let the trampoline
568 * deal with the userland scheduler on return to userland.
7d0bac62 569 */
553ea3c8 570 KASSERT(p2->p_stat == SIDL,
7d0bac62 571 ("cannot start forked process, bad status: %p", p2));
553ea3c8 572 p2->p_usched->resetpriority(lp2);
e43a034f 573 crit_enter();
7d0bac62 574 p2->p_stat = SRUN;
553ea3c8 575 p2->p_usched->setrunqueue(lp2);
e43a034f 576 crit_exit();
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577
578 /*
579 * Now can be swapped.
580 */
553ea3c8 581 PRELE(lp1->lwp_proc);
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582
583 /*
584 * Preserve synchronization semantics of vfork. If waiting for
585 * child to exec or exit, set P_PPWAIT on child, and sleep on our
586 * proc (in case of exit).
587 */
588 while (p2->p_flag & P_PPWAIT)
553ea3c8 589 tsleep(lp1->lwp_proc, 0, "ppwait", 0);
7d0bac62 590}