xref: /freebsd/sys/kern/init_main.c (revision f9218d3d4fd34f082473b3a021c6d4d109fb47cf)
1 /*
2  * Copyright (c) 1995 Terrence R. Lambert
3  * All rights reserved.
4  *
5  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  * (c) UNIX System Laboratories, Inc.
8  * All or some portions of this file are derived from material licensed
9  * to the University of California by American Telephone and Telegraph
10  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11  * the permission of UNIX System Laboratories, Inc.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by the University of
24  *	California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	@(#)init_main.c	8.9 (Berkeley) 1/21/94
42  * $FreeBSD$
43  */
44 
45 #include "opt_init_path.h"
46 #include "opt_mac.h"
47 
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/exec.h>
51 #include <sys/file.h>
52 #include <sys/filedesc.h>
53 #include <sys/ktr.h>
54 #include <sys/lock.h>
55 #include <sys/mac.h>
56 #include <sys/mount.h>
57 #include <sys/mutex.h>
58 #include <sys/syscallsubr.h>
59 #include <sys/sysctl.h>
60 #include <sys/proc.h>
61 #include <sys/resourcevar.h>
62 #include <sys/systm.h>
63 #include <sys/signalvar.h>
64 #include <sys/vnode.h>
65 #include <sys/sysent.h>
66 #include <sys/reboot.h>
67 #include <sys/sched.h>
68 #include <sys/sx.h>
69 #include <sys/sysproto.h>
70 #include <sys/vmmeter.h>
71 #include <sys/unistd.h>
72 #include <sys/malloc.h>
73 #include <sys/conf.h>
74 
75 #include <machine/cpu.h>
76 
77 #include <vm/vm.h>
78 #include <vm/vm_param.h>
79 #include <vm/pmap.h>
80 #include <vm/vm_map.h>
81 #include <sys/user.h>
82 #include <sys/copyright.h>
83 
84 void mi_startup(void);				/* Should be elsewhere */
85 
86 /* Components of the first process -- never freed. */
87 static struct session session0;
88 static struct pgrp pgrp0;
89 struct	proc proc0;
90 struct	thread thread0;
91 struct	kse kse0;
92 struct	ksegrp ksegrp0;
93 static struct procsig procsig0;
94 static struct filedesc0 filedesc0;
95 static struct plimit limit0;
96 static struct vmspace vmspace0;
97 struct	proc *initproc;
98 
99 int cmask = CMASK;
100 
101 struct	vnode *rootvp;
102 int	boothowto = 0;		/* initialized so that it can be patched */
103 SYSCTL_INT(_debug, OID_AUTO, boothowto, CTLFLAG_RD, &boothowto, 0, "");
104 int	bootverbose;
105 SYSCTL_INT(_debug, OID_AUTO, bootverbose, CTLFLAG_RW, &bootverbose, 0, "");
106 
107 /*
108  * This ensures that there is at least one entry so that the sysinit_set
109  * symbol is not undefined.  A sybsystem ID of SI_SUB_DUMMY is never
110  * executed.
111  */
112 SYSINIT(placeholder, SI_SUB_DUMMY, SI_ORDER_ANY, NULL, NULL)
113 
114 /*
115  * The sysinit table itself.  Items are checked off as the are run.
116  * If we want to register new sysinit types, add them to newsysinit.
117  */
118 SET_DECLARE(sysinit_set, struct sysinit);
119 struct sysinit **sysinit, **sysinit_end;
120 struct sysinit **newsysinit, **newsysinit_end;
121 
122 /*
123  * Merge a new sysinit set into the current set, reallocating it if
124  * necessary.  This can only be called after malloc is running.
125  */
126 void
127 sysinit_add(struct sysinit **set, struct sysinit **set_end)
128 {
129 	struct sysinit **newset;
130 	struct sysinit **sipp;
131 	struct sysinit **xipp;
132 	int count;
133 
134 	count = set_end - set;
135 	if (newsysinit)
136 		count += newsysinit_end - newsysinit;
137 	else
138 		count += sysinit_end - sysinit;
139 	newset = malloc(count * sizeof(*sipp), M_TEMP, M_NOWAIT);
140 	if (newset == NULL)
141 		panic("cannot malloc for sysinit");
142 	xipp = newset;
143 	if (newsysinit)
144 		for (sipp = newsysinit; sipp < newsysinit_end; sipp++)
145 			*xipp++ = *sipp;
146 	else
147 		for (sipp = sysinit; sipp < sysinit_end; sipp++)
148 			*xipp++ = *sipp;
149 	for (sipp = set; sipp < set_end; sipp++)
150 		*xipp++ = *sipp;
151 	if (newsysinit)
152 		free(newsysinit, M_TEMP);
153 	newsysinit = newset;
154 	newsysinit_end = newset + count;
155 }
156 
157 /*
158  * System startup; initialize the world, create process 0, mount root
159  * filesystem, and fork to create init and pagedaemon.  Most of the
160  * hard work is done in the lower-level initialization routines including
161  * startup(), which does memory initialization and autoconfiguration.
162  *
163  * This allows simple addition of new kernel subsystems that require
164  * boot time initialization.  It also allows substitution of subsystem
165  * (for instance, a scheduler, kernel profiler, or VM system) by object
166  * module.  Finally, it allows for optional "kernel threads".
167  */
168 void
169 mi_startup(void)
170 {
171 
172 	register struct sysinit **sipp;		/* system initialization*/
173 	register struct sysinit **xipp;		/* interior loop of sort*/
174 	register struct sysinit *save;		/* bubble*/
175 
176 	if (sysinit == NULL) {
177 		sysinit = SET_BEGIN(sysinit_set);
178 		sysinit_end = SET_LIMIT(sysinit_set);
179 	}
180 
181 restart:
182 	/*
183 	 * Perform a bubble sort of the system initialization objects by
184 	 * their subsystem (primary key) and order (secondary key).
185 	 */
186 	for (sipp = sysinit; sipp < sysinit_end; sipp++) {
187 		for (xipp = sipp + 1; xipp < sysinit_end; xipp++) {
188 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
189 			     ((*sipp)->subsystem == (*xipp)->subsystem &&
190 			      (*sipp)->order <= (*xipp)->order))
191 				continue;	/* skip*/
192 			save = *sipp;
193 			*sipp = *xipp;
194 			*xipp = save;
195 		}
196 	}
197 
198 	/*
199 	 * Traverse the (now) ordered list of system initialization tasks.
200 	 * Perform each task, and continue on to the next task.
201 	 *
202 	 * The last item on the list is expected to be the scheduler,
203 	 * which will not return.
204 	 */
205 	for (sipp = sysinit; sipp < sysinit_end; sipp++) {
206 
207 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
208 			continue;	/* skip dummy task(s)*/
209 
210 		if ((*sipp)->subsystem == SI_SUB_DONE)
211 			continue;
212 
213 		/* Call function */
214 		(*((*sipp)->func))((*sipp)->udata);
215 
216 		/* Check off the one we're just done */
217 		(*sipp)->subsystem = SI_SUB_DONE;
218 
219 		/* Check if we've installed more sysinit items via KLD */
220 		if (newsysinit != NULL) {
221 			if (sysinit != SET_BEGIN(sysinit_set))
222 				free(sysinit, M_TEMP);
223 			sysinit = newsysinit;
224 			sysinit_end = newsysinit_end;
225 			newsysinit = NULL;
226 			newsysinit_end = NULL;
227 			goto restart;
228 		}
229 	}
230 
231 	panic("Shouldn't get here!");
232 	/* NOTREACHED*/
233 }
234 
235 
236 /*
237  ***************************************************************************
238  ****
239  **** The following SYSINIT's belong elsewhere, but have not yet
240  **** been moved.
241  ****
242  ***************************************************************************
243  */
244 static void
245 print_caddr_t(void *data __unused)
246 {
247 	printf("%s", (char *)data);
248 }
249 SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t, copyright)
250 SYSINIT(version, SI_SUB_COPYRIGHT, SI_ORDER_SECOND, print_caddr_t, version)
251 
252 static void
253 set_boot_verbose(void *data __unused)
254 {
255 
256 	if (boothowto & RB_VERBOSE)
257 		bootverbose++;
258 }
259 SYSINIT(boot_verbose, SI_SUB_TUNABLES, SI_ORDER_ANY, set_boot_verbose, NULL)
260 
261 struct sysentvec null_sysvec = {
262 	0,
263 	NULL,
264 	0,
265 	0,
266 	NULL,
267 	0,
268 	NULL,
269 	NULL,
270 	NULL,
271 	NULL,
272 	NULL,
273 	NULL,
274 	NULL,
275 	"null",
276 	NULL,
277 	NULL,
278 	0,
279 	PAGE_SIZE,
280 	VM_MIN_ADDRESS,
281 	VM_MAXUSER_ADDRESS,
282 	USRSTACK,
283 	PS_STRINGS,
284 	VM_PROT_ALL,
285 	NULL,
286 	NULL
287 };
288 
289 /*
290  ***************************************************************************
291  ****
292  **** The two following SYSINIT's are proc0 specific glue code.  I am not
293  **** convinced that they can not be safely combined, but their order of
294  **** operation has been maintained as the same as the original init_main.c
295  **** for right now.
296  ****
297  **** These probably belong in init_proc.c or kern_proc.c, since they
298  **** deal with proc0 (the fork template process).
299  ****
300  ***************************************************************************
301  */
302 /* ARGSUSED*/
303 static void
304 proc0_init(void *dummy __unused)
305 {
306 	register struct proc		*p;
307 	register struct filedesc0	*fdp;
308 	register unsigned i;
309 	struct thread *td;
310 	struct ksegrp *kg;
311 	struct kse *ke;
312 
313 	GIANT_REQUIRED;
314 	p = &proc0;
315 	td = &thread0;
316 	ke = &kse0;
317 	kg = &ksegrp0;
318 
319 	ke->ke_sched = kse0_sched;
320 	kg->kg_sched = ksegrp0_sched;
321 	p->p_sched = proc0_sched;
322 	td->td_sched = thread0_sched;
323 
324 	/*
325 	 * Initialize magic number.
326 	 */
327 	p->p_magic = P_MAGIC;
328 
329 	/*
330 	 * Initialize thread, process and pgrp structures.
331 	 */
332 	procinit();
333 	threadinit();
334 
335 	/*
336 	 * Initialize sleep queue hash table
337 	 */
338 	sleepinit();
339 
340 	/*
341 	 * additional VM structures
342 	 */
343 	vm_init2();
344 
345 	/*
346 	 * Create process 0 (the swapper).
347 	 */
348 	LIST_INSERT_HEAD(&allproc, p, p_list);
349 	LIST_INSERT_HEAD(PIDHASH(0), p, p_hash);
350 	mtx_init(&pgrp0.pg_mtx, "process group", NULL, MTX_DEF | MTX_DUPOK);
351 	p->p_pgrp = &pgrp0;
352 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
353 	LIST_INIT(&pgrp0.pg_members);
354 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
355 
356 	pgrp0.pg_session = &session0;
357 	mtx_init(&session0.s_mtx, "session", NULL, MTX_DEF);
358 	session0.s_count = 1;
359 	session0.s_leader = p;
360 
361 	p->p_sysent = &null_sysvec;
362 
363 	/*
364 	 * proc_linkup was already done in init_i386() or alphainit() etc.
365 	 * because the earlier code needed to follow td->td_proc. Otherwise
366 	 * I would have done it here.. maybe this means this should be
367 	 * done earlier too.
368 	 */
369 	p->p_flag = P_SYSTEM;
370 	p->p_sflag = PS_INMEM;
371 	p->p_state = PRS_NORMAL;
372 	td->td_state = TDS_RUNNING;
373 	kg->kg_nice = NZERO;
374 	kg->kg_pri_class = PRI_TIMESHARE;
375 	kg->kg_user_pri = PUSER;
376 	td->td_priority = PVM;
377 	td->td_base_pri = PUSER;
378 	td->td_kse = ke; /* XXXKSE */
379 	ke->ke_oncpu = 0;
380 	ke->ke_state = KES_THREAD;
381 	ke->ke_thread = td;
382 	p->p_peers = 0;
383 	p->p_leader = p;
384 
385 
386 	bcopy("swapper", p->p_comm, sizeof ("swapper"));
387 
388 	callout_init(&p->p_itcallout, 1);
389 	callout_init(&td->td_slpcallout, 1);
390 
391 	/* Create credentials. */
392 	p->p_ucred = crget();
393 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
394 	p->p_ucred->cr_uidinfo = uifind(0);
395 	p->p_ucred->cr_ruidinfo = uifind(0);
396 	p->p_ucred->cr_prison = NULL;	/* Don't jail it. */
397 #ifdef MAC
398 	mac_create_proc0(p->p_ucred);
399 #endif
400 	td->td_ucred = crhold(p->p_ucred);
401 
402 	/* Create procsig. */
403 	p->p_procsig = &procsig0;
404 	p->p_procsig->ps_refcnt = 1;
405 
406 	/* Initialize signal state for process 0. */
407 	siginit(&proc0);
408 
409 	/* Create the file descriptor table. */
410 	fdp = &filedesc0;
411 	p->p_fd = &fdp->fd_fd;
412 	mtx_init(&fdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF);
413 	fdp->fd_fd.fd_refcnt = 1;
414 	fdp->fd_fd.fd_cmask = cmask;
415 	fdp->fd_fd.fd_ofiles = fdp->fd_dfiles;
416 	fdp->fd_fd.fd_ofileflags = fdp->fd_dfileflags;
417 	fdp->fd_fd.fd_nfiles = NDFILE;
418 
419 	/* Create the limits structures. */
420 	p->p_limit = &limit0;
421 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
422 		limit0.pl_rlimit[i].rlim_cur =
423 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
424 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
425 	    limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
426 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
427 	    limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
428 	i = ptoa(cnt.v_free_count);
429 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = i;
430 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = i;
431 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = i / 3;
432 	limit0.p_refcnt = 1;
433 	p->p_cpulimit = RLIM_INFINITY;
434 
435 	/* Allocate a prototype map so we have something to fork. */
436 	pmap_pinit0(vmspace_pmap(&vmspace0));
437 	p->p_vmspace = &vmspace0;
438 	vmspace0.vm_refcnt = 1;
439 	vm_map_init(&vmspace0.vm_map, p->p_sysent->sv_minuser,
440 	    p->p_sysent->sv_maxuser);
441 	vmspace0.vm_map.pmap = vmspace_pmap(&vmspace0);
442 
443 	/*
444 	 * We continue to place resource usage info and signal
445 	 * actions in the user struct so they're pageable.
446 	 */
447 	p->p_stats = &p->p_uarea->u_stats;
448 	p->p_sigacts = &p->p_uarea->u_sigacts;
449 
450 	/*
451 	 * Charge root for one process.
452 	 */
453 	(void)chgproccnt(p->p_ucred->cr_ruidinfo, 1, 0);
454 }
455 SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST, proc0_init, NULL)
456 
457 /* ARGSUSED*/
458 static void
459 proc0_post(void *dummy __unused)
460 {
461 	struct timespec ts;
462 	struct proc *p;
463 
464 	/*
465 	 * Now we can look at the time, having had a chance to verify the
466 	 * time from the filesystem.  Pretend that proc0 started now.
467 	 */
468 	sx_slock(&allproc_lock);
469 	LIST_FOREACH(p, &allproc, p_list) {
470 		microtime(&p->p_stats->p_start);
471 		p->p_runtime.sec = 0;
472 		p->p_runtime.frac = 0;
473 	}
474 	sx_sunlock(&allproc_lock);
475 	binuptime(PCPU_PTR(switchtime));
476 	PCPU_SET(switchticks, ticks);
477 
478 	/*
479 	 * Give the ``random'' number generator a thump.
480 	 */
481 	nanotime(&ts);
482 	srandom(ts.tv_sec ^ ts.tv_nsec);
483 }
484 SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL)
485 
486 /*
487  ***************************************************************************
488  ****
489  **** The following SYSINIT's and glue code should be moved to the
490  **** respective files on a per subsystem basis.
491  ****
492  ***************************************************************************
493  */
494 
495 
496 /*
497  ***************************************************************************
498  ****
499  **** The following code probably belongs in another file, like
500  **** kern/init_init.c.
501  ****
502  ***************************************************************************
503  */
504 
505 /*
506  * List of paths to try when searching for "init".
507  */
508 static char init_path[MAXPATHLEN] =
509 #ifdef	INIT_PATH
510     __XSTRING(INIT_PATH);
511 #else
512     "/sbin/init:/sbin/oinit:/sbin/init.bak:/stand/sysinstall";
513 #endif
514 SYSCTL_STRING(_kern, OID_AUTO, init_path, CTLFLAG_RD, init_path, 0,
515 	"Path used to search the init process");
516 
517 /*
518  * Start the initial user process; try exec'ing each pathname in init_path.
519  * The program is invoked with one argument containing the boot flags.
520  */
521 static void
522 start_init(void *dummy)
523 {
524 	vm_offset_t addr;
525 	struct execve_args args;
526 	int options, error;
527 	char *var, *path, *next, *s;
528 	char *ucp, **uap, *arg0, *arg1;
529 	struct thread *td;
530 	struct proc *p;
531 	int init_does_devfs = 0;
532 
533 	mtx_lock(&Giant);
534 
535 	GIANT_REQUIRED;
536 
537 	td = curthread;
538 	p = td->td_proc;
539 
540 	vfs_mountroot();
541 
542 	/* Get the vnode for '/'.  Set p->p_fd->fd_cdir to reference it. */
543 	if (VFS_ROOT(TAILQ_FIRST(&mountlist), &rootvnode))
544 		panic("cannot find root vnode");
545 	FILEDESC_LOCK(p->p_fd);
546 	p->p_fd->fd_cdir = rootvnode;
547 	VREF(p->p_fd->fd_cdir);
548 	p->p_fd->fd_rdir = rootvnode;
549 	VREF(p->p_fd->fd_rdir);
550 	FILEDESC_UNLOCK(p->p_fd);
551 	VOP_UNLOCK(rootvnode, 0, td);
552 #ifdef MAC
553 	mac_create_root_mount(td->td_ucred, TAILQ_FIRST(&mountlist));
554 #endif
555 
556 	/*
557 	 * For disk based systems, we probably cannot do this yet
558 	 * since the fs will be read-only.  But a NFS root
559 	 * might be ok.  It is worth a shot.
560 	 */
561 	error = kern_mkdir(td, "/dev", UIO_SYSSPACE, 0700);
562 	if (error == EEXIST)
563 		error = 0;
564 	if (error == 0)
565 		error = kernel_vmount(0, "fstype", "devfs",
566 		    "fspath", "/dev", NULL);
567 	if (error != 0)
568 		init_does_devfs = 1;
569 
570 	/*
571 	 * Need just enough stack to hold the faked-up "execve()" arguments.
572 	 */
573 	addr = p->p_sysent->sv_usrstack - PAGE_SIZE;
574 	if (vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, PAGE_SIZE,
575 			FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != 0)
576 		panic("init: couldn't allocate argument space");
577 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
578 	p->p_vmspace->vm_ssize = 1;
579 
580 	if ((var = getenv("init_path")) != NULL) {
581 		strlcpy(init_path, var, sizeof(init_path));
582 		freeenv(var);
583 	}
584 
585 	for (path = init_path; *path != '\0'; path = next) {
586 		while (*path == ':')
587 			path++;
588 		if (*path == '\0')
589 			break;
590 		for (next = path; *next != '\0' && *next != ':'; next++)
591 			/* nothing */ ;
592 		if (bootverbose)
593 			printf("start_init: trying %.*s\n", (int)(next - path),
594 			    path);
595 
596 		/*
597 		 * Move out the boot flag argument.
598 		 */
599 		options = 0;
600 		ucp = (char *)p->p_sysent->sv_usrstack;
601 		(void)subyte(--ucp, 0);		/* trailing zero */
602 		if (boothowto & RB_SINGLE) {
603 			(void)subyte(--ucp, 's');
604 			options = 1;
605 		}
606 #ifdef notyet
607                 if (boothowto & RB_FASTBOOT) {
608 			(void)subyte(--ucp, 'f');
609 			options = 1;
610 		}
611 #endif
612 
613 #ifdef BOOTCDROM
614 		(void)subyte(--ucp, 'C');
615 		options = 1;
616 #endif
617 		if (init_does_devfs) {
618 			(void)subyte(--ucp, 'd');
619 			options = 1;
620 		}
621 
622 		if (options == 0)
623 			(void)subyte(--ucp, '-');
624 		(void)subyte(--ucp, '-');		/* leading hyphen */
625 		arg1 = ucp;
626 
627 		/*
628 		 * Move out the file name (also arg 0).
629 		 */
630 		(void)subyte(--ucp, 0);
631 		for (s = next - 1; s >= path; s--)
632 			(void)subyte(--ucp, *s);
633 		arg0 = ucp;
634 
635 		/*
636 		 * Move out the arg pointers.
637 		 */
638 		uap = (char **)((intptr_t)ucp & ~(sizeof(intptr_t)-1));
639 		(void)suword((caddr_t)--uap, (long)0);	/* terminator */
640 		(void)suword((caddr_t)--uap, (long)(intptr_t)arg1);
641 		(void)suword((caddr_t)--uap, (long)(intptr_t)arg0);
642 
643 		/*
644 		 * Point at the arguments.
645 		 */
646 		args.fname = arg0;
647 		args.argv = uap;
648 		args.envv = NULL;
649 
650 		/*
651 		 * Now try to exec the program.  If can't for any reason
652 		 * other than it doesn't exist, complain.
653 		 *
654 		 * Otherwise, return via fork_trampoline() all the way
655 		 * to user mode as init!
656 		 */
657 		if ((error = execve(td, &args)) == 0) {
658 			mtx_unlock(&Giant);
659 			return;
660 		}
661 		if (error != ENOENT)
662 			printf("exec %.*s: error %d\n", (int)(next - path),
663 			    path, error);
664 	}
665 	printf("init: not found in path %s\n", init_path);
666 	panic("no init");
667 }
668 
669 /*
670  * Like kthread_create(), but runs in it's own address space.
671  * We do this early to reserve pid 1.
672  *
673  * Note special case - do not make it runnable yet.  Other work
674  * in progress will change this more.
675  */
676 static void
677 create_init(const void *udata __unused)
678 {
679 	struct ucred *newcred, *oldcred;
680 	int error;
681 
682 	error = fork1(&thread0, RFFDG | RFPROC | RFSTOPPED, 0, &initproc);
683 	if (error)
684 		panic("cannot fork init: %d\n", error);
685 	/* divorce init's credentials from the kernel's */
686 	newcred = crget();
687 	PROC_LOCK(initproc);
688 	initproc->p_flag |= P_SYSTEM;
689 	oldcred = initproc->p_ucred;
690 	crcopy(newcred, oldcred);
691 #ifdef MAC
692 	mac_create_proc1(newcred);
693 #endif
694 	initproc->p_ucred = newcred;
695 	PROC_UNLOCK(initproc);
696 	crfree(oldcred);
697 	cred_update_thread(FIRST_THREAD_IN_PROC(initproc));
698 	mtx_lock_spin(&sched_lock);
699 	initproc->p_sflag |= PS_INMEM;
700 	mtx_unlock_spin(&sched_lock);
701 	cpu_set_fork_handler(FIRST_THREAD_IN_PROC(initproc), start_init, NULL);
702 }
703 SYSINIT(init, SI_SUB_CREATE_INIT, SI_ORDER_FIRST, create_init, NULL)
704 
705 /*
706  * Make it runnable now.
707  */
708 static void
709 kick_init(const void *udata __unused)
710 {
711 	struct thread *td;
712 
713 	td = FIRST_THREAD_IN_PROC(initproc);
714 	mtx_lock_spin(&sched_lock);
715 	TD_SET_CAN_RUN(td);
716 	setrunqueue(td);	/* XXXKSE */
717 	mtx_unlock_spin(&sched_lock);
718 }
719 SYSINIT(kickinit, SI_SUB_KTHREAD_INIT, SI_ORDER_FIRST, kick_init, NULL)
720