xref: /freebsd/sys/kern/init_main.c (revision 7d0d268b8a67f28ccefdd0b8ce6fb38acac78d80)
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  */
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #include "opt_ddb.h"
48 #include "opt_init_path.h"
49 #include "opt_mac.h"
50 
51 #include <sys/param.h>
52 #include <sys/kernel.h>
53 #include <sys/exec.h>
54 #include <sys/file.h>
55 #include <sys/filedesc.h>
56 #include <sys/ktr.h>
57 #include <sys/lock.h>
58 #include <sys/mount.h>
59 #include <sys/mutex.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/sysctl.h>
62 #include <sys/proc.h>
63 #include <sys/resourcevar.h>
64 #include <sys/systm.h>
65 #include <sys/signalvar.h>
66 #include <sys/vnode.h>
67 #include <sys/sysent.h>
68 #include <sys/reboot.h>
69 #include <sys/sched.h>
70 #include <sys/sx.h>
71 #include <sys/sysproto.h>
72 #include <sys/vmmeter.h>
73 #include <sys/unistd.h>
74 #include <sys/malloc.h>
75 #include <sys/conf.h>
76 #include <sys/cpuset.h>
77 
78 #include <machine/cpu.h>
79 
80 #include <security/audit/audit.h>
81 #include <security/mac/mac_framework.h>
82 
83 #include <vm/vm.h>
84 #include <vm/vm_param.h>
85 #include <vm/pmap.h>
86 #include <vm/vm_map.h>
87 #include <sys/copyright.h>
88 
89 #include <ddb/ddb.h>
90 #include <ddb/db_sym.h>
91 
92 void mi_startup(void);				/* Should be elsewhere */
93 
94 /* Components of the first process -- never freed. */
95 static struct session session0;
96 static struct pgrp pgrp0;
97 struct	proc proc0;
98 struct	thread thread0 __aligned(16);
99 struct	vmspace vmspace0;
100 struct	proc *initproc;
101 
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 defined(VERBOSE_SYSINIT)
177 	int last;
178 	int verbose;
179 #endif
180 
181 	if (sysinit == NULL) {
182 		sysinit = SET_BEGIN(sysinit_set);
183 		sysinit_end = SET_LIMIT(sysinit_set);
184 	}
185 
186 restart:
187 	/*
188 	 * Perform a bubble sort of the system initialization objects by
189 	 * their subsystem (primary key) and order (secondary key).
190 	 */
191 	for (sipp = sysinit; sipp < sysinit_end; sipp++) {
192 		for (xipp = sipp + 1; xipp < sysinit_end; xipp++) {
193 			if ((*sipp)->subsystem < (*xipp)->subsystem ||
194 			     ((*sipp)->subsystem == (*xipp)->subsystem &&
195 			      (*sipp)->order <= (*xipp)->order))
196 				continue;	/* skip*/
197 			save = *sipp;
198 			*sipp = *xipp;
199 			*xipp = save;
200 		}
201 	}
202 
203 #if defined(VERBOSE_SYSINIT)
204 	last = SI_SUB_COPYRIGHT;
205 	verbose = 0;
206 #if !defined(DDB)
207 	printf("VERBOSE_SYSINIT: DDB not enabled, symbol lookups disabled.\n");
208 #endif
209 #endif
210 
211 	/*
212 	 * Traverse the (now) ordered list of system initialization tasks.
213 	 * Perform each task, and continue on to the next task.
214 	 *
215 	 * The last item on the list is expected to be the scheduler,
216 	 * which will not return.
217 	 */
218 	for (sipp = sysinit; sipp < sysinit_end; sipp++) {
219 
220 		if ((*sipp)->subsystem == SI_SUB_DUMMY)
221 			continue;	/* skip dummy task(s)*/
222 
223 		if ((*sipp)->subsystem == SI_SUB_DONE)
224 			continue;
225 
226 #if defined(VERBOSE_SYSINIT)
227 		if ((*sipp)->subsystem > last) {
228 			verbose = 1;
229 			last = (*sipp)->subsystem;
230 			printf("subsystem %x\n", last);
231 		}
232 		if (verbose) {
233 #if defined(DDB)
234 			const char *name;
235 			c_db_sym_t sym;
236 			db_expr_t  offset;
237 
238 			sym = db_search_symbol((vm_offset_t)(*sipp)->func,
239 			    DB_STGY_PROC, &offset);
240 			db_symbol_values(sym, &name, NULL);
241 			if (name != NULL)
242 				printf("   %s(%p)... ", name, (*sipp)->udata);
243 			else
244 #endif
245 				printf("   %p(%p)... ", (*sipp)->func,
246 				    (*sipp)->udata);
247 		}
248 #endif
249 
250 		/* Call function */
251 		(*((*sipp)->func))((*sipp)->udata);
252 
253 #if defined(VERBOSE_SYSINIT)
254 		if (verbose)
255 			printf("done.\n");
256 #endif
257 
258 		/* Check off the one we're just done */
259 		(*sipp)->subsystem = SI_SUB_DONE;
260 
261 		/* Check if we've installed more sysinit items via KLD */
262 		if (newsysinit != NULL) {
263 			if (sysinit != SET_BEGIN(sysinit_set))
264 				free(sysinit, M_TEMP);
265 			sysinit = newsysinit;
266 			sysinit_end = newsysinit_end;
267 			newsysinit = NULL;
268 			newsysinit_end = NULL;
269 			goto restart;
270 		}
271 	}
272 
273 	panic("Shouldn't get here!");
274 	/* NOTREACHED*/
275 }
276 
277 
278 /*
279  ***************************************************************************
280  ****
281  **** The following SYSINIT's belong elsewhere, but have not yet
282  **** been moved.
283  ****
284  ***************************************************************************
285  */
286 static void
287 print_caddr_t(void *data __unused)
288 {
289 	printf("%s", (char *)data);
290 }
291 SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t,
292     copyright);
293 SYSINIT(trademark, SI_SUB_COPYRIGHT, SI_ORDER_SECOND, print_caddr_t,
294     trademark);
295 SYSINIT(version, SI_SUB_COPYRIGHT, SI_ORDER_THIRD, print_caddr_t, version);
296 
297 #ifdef WITNESS
298 static char wit_warn[] =
299      "WARNING: WITNESS option enabled, expect reduced performance.\n";
300 SYSINIT(witwarn, SI_SUB_COPYRIGHT, SI_ORDER_THIRD + 1,
301    print_caddr_t, wit_warn);
302 SYSINIT(witwarn2, SI_SUB_RUN_SCHEDULER, SI_ORDER_THIRD + 1,
303    print_caddr_t, wit_warn);
304 #endif
305 
306 #ifdef DIAGNOSTIC
307 static char diag_warn[] =
308      "WARNING: DIAGNOSTIC option enabled, expect reduced performance.\n";
309 SYSINIT(diagwarn, SI_SUB_COPYRIGHT, SI_ORDER_THIRD + 2,
310     print_caddr_t, diag_warn);
311 SYSINIT(diagwarn2, SI_SUB_RUN_SCHEDULER, SI_ORDER_THIRD + 2,
312     print_caddr_t, diag_warn);
313 #endif
314 
315 static void
316 set_boot_verbose(void *data __unused)
317 {
318 
319 	if (boothowto & RB_VERBOSE)
320 		bootverbose++;
321 }
322 SYSINIT(boot_verbose, SI_SUB_TUNABLES, SI_ORDER_ANY, set_boot_verbose, NULL);
323 
324 struct sysentvec null_sysvec = {
325 	.sv_size	= 0,
326 	.sv_table	= NULL,
327 	.sv_mask	= 0,
328 	.sv_sigsize	= 0,
329 	.sv_sigtbl	= NULL,
330 	.sv_errsize	= 0,
331 	.sv_errtbl	= NULL,
332 	.sv_transtrap	= NULL,
333 	.sv_fixup	= NULL,
334 	.sv_sendsig	= NULL,
335 	.sv_sigcode	= NULL,
336 	.sv_szsigcode	= NULL,
337 	.sv_prepsyscall	= NULL,
338 	.sv_name	= "null",
339 	.sv_coredump	= NULL,
340 	.sv_imgact_try	= NULL,
341 	.sv_minsigstksz	= 0,
342 	.sv_pagesize	= PAGE_SIZE,
343 	.sv_minuser	= VM_MIN_ADDRESS,
344 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
345 	.sv_usrstack	= USRSTACK,
346 	.sv_psstrings	= PS_STRINGS,
347 	.sv_stackprot	= VM_PROT_ALL,
348 	.sv_copyout_strings	= NULL,
349 	.sv_setregs	= NULL,
350 	.sv_fixlimit	= NULL,
351 	.sv_maxssiz	= NULL
352 };
353 
354 /*
355  ***************************************************************************
356  ****
357  **** The two following SYSINIT's are proc0 specific glue code.  I am not
358  **** convinced that they can not be safely combined, but their order of
359  **** operation has been maintained as the same as the original init_main.c
360  **** for right now.
361  ****
362  **** These probably belong in init_proc.c or kern_proc.c, since they
363  **** deal with proc0 (the fork template process).
364  ****
365  ***************************************************************************
366  */
367 /* ARGSUSED*/
368 static void
369 proc0_init(void *dummy __unused)
370 {
371 	struct proc *p;
372 	unsigned i;
373 	struct thread *td;
374 
375 	GIANT_REQUIRED;
376 	p = &proc0;
377 	td = &thread0;
378 
379 	/*
380 	 * Initialize magic number and osrel.
381 	 */
382 	p->p_magic = P_MAGIC;
383 	p->p_osrel = osreldate;
384 
385 	/*
386 	 * Initialize thread and process structures.
387 	 */
388 	procinit();	/* set up proc zone */
389 	threadinit();	/* set up UMA zones */
390 
391 	/*
392 	 * Initialise scheduler resources.
393 	 * Add scheduler specific parts to proc, thread as needed.
394 	 */
395 	schedinit();	/* scheduler gets its house in order */
396 	/*
397 	 * Initialize sleep queue hash table
398 	 */
399 	sleepinit();
400 
401 	/*
402 	 * additional VM structures
403 	 */
404 	vm_init2();
405 
406 	/*
407 	 * Create process 0 (the swapper).
408 	 */
409 	LIST_INSERT_HEAD(&allproc, p, p_list);
410 	LIST_INSERT_HEAD(PIDHASH(0), p, p_hash);
411 	mtx_init(&pgrp0.pg_mtx, "process group", NULL, MTX_DEF | MTX_DUPOK);
412 	p->p_pgrp = &pgrp0;
413 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
414 	LIST_INIT(&pgrp0.pg_members);
415 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
416 
417 	pgrp0.pg_session = &session0;
418 	mtx_init(&session0.s_mtx, "session", NULL, MTX_DEF);
419 	refcount_init(&session0.s_count, 1);
420 	session0.s_leader = p;
421 
422 	p->p_sysent = &null_sysvec;
423 	p->p_flag = P_SYSTEM | P_INMEM;
424 	p->p_state = PRS_NORMAL;
425 	knlist_init(&p->p_klist, &p->p_mtx, NULL, NULL, NULL);
426 	STAILQ_INIT(&p->p_ktr);
427 	p->p_nice = NZERO;
428 	td->td_tid = PID_MAX + 1;
429 	td->td_state = TDS_RUNNING;
430 	td->td_pri_class = PRI_TIMESHARE;
431 	td->td_user_pri = PUSER;
432 	td->td_base_user_pri = PUSER;
433 	td->td_priority = PVM;
434 	td->td_base_pri = PUSER;
435 	td->td_oncpu = 0;
436 	td->td_flags = TDF_INMEM|TDP_KTHREAD;
437 	td->td_cpuset = cpuset_thread0();
438 	p->p_peers = 0;
439 	p->p_leader = p;
440 
441 
442 	strncpy(p->p_comm, "kernel", sizeof (p->p_comm));
443 	strncpy(td->td_name, "swapper", sizeof (td->td_name));
444 
445 	callout_init(&p->p_itcallout, CALLOUT_MPSAFE);
446 	callout_init_mtx(&p->p_limco, &p->p_mtx, 0);
447 	callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
448 
449 	/* Create credentials. */
450 	p->p_ucred = crget();
451 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
452 	p->p_ucred->cr_uidinfo = uifind(0);
453 	p->p_ucred->cr_ruidinfo = uifind(0);
454 	p->p_ucred->cr_prison = NULL;	/* Don't jail it. */
455 #ifdef AUDIT
456 	audit_cred_kproc0(p->p_ucred);
457 #endif
458 #ifdef MAC
459 	mac_cred_create_swapper(p->p_ucred);
460 #endif
461 	td->td_ucred = crhold(p->p_ucred);
462 
463 	/* Create sigacts. */
464 	p->p_sigacts = sigacts_alloc();
465 
466 	/* Initialize signal state for process 0. */
467 	siginit(&proc0);
468 
469 	/* Create the file descriptor table. */
470 	p->p_fd = fdinit(NULL);
471 	p->p_fdtol = NULL;
472 
473 	/* Create the limits structures. */
474 	p->p_limit = lim_alloc();
475 	for (i = 0; i < RLIM_NLIMITS; i++)
476 		p->p_limit->pl_rlimit[i].rlim_cur =
477 		    p->p_limit->pl_rlimit[i].rlim_max = RLIM_INFINITY;
478 	p->p_limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur =
479 	    p->p_limit->pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
480 	p->p_limit->pl_rlimit[RLIMIT_NPROC].rlim_cur =
481 	    p->p_limit->pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
482 	i = ptoa(cnt.v_free_count);
483 	p->p_limit->pl_rlimit[RLIMIT_RSS].rlim_max = i;
484 	p->p_limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = i;
485 	p->p_limit->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = i / 3;
486 	p->p_cpulimit = RLIM_INFINITY;
487 
488 	p->p_stats = pstats_alloc();
489 
490 	/* Allocate a prototype map so we have something to fork. */
491 	pmap_pinit0(vmspace_pmap(&vmspace0));
492 	p->p_vmspace = &vmspace0;
493 	vmspace0.vm_refcnt = 1;
494 	vm_map_init(&vmspace0.vm_map, p->p_sysent->sv_minuser,
495 	    p->p_sysent->sv_maxuser);
496 	vmspace0.vm_map.pmap = vmspace_pmap(&vmspace0);
497 
498 	/*-
499 	 * call the init and ctor for the new thread and proc
500 	 * we wait to do this until all other structures
501 	 * are fairly sane.
502 	 */
503 	EVENTHANDLER_INVOKE(process_init, p);
504 	EVENTHANDLER_INVOKE(thread_init, td);
505 	EVENTHANDLER_INVOKE(process_ctor, p);
506 	EVENTHANDLER_INVOKE(thread_ctor, td);
507 
508 	/*
509 	 * Charge root for one process.
510 	 */
511 	(void)chgproccnt(p->p_ucred->cr_ruidinfo, 1, 0);
512 }
513 SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST, proc0_init, NULL);
514 
515 /* ARGSUSED*/
516 static void
517 proc0_post(void *dummy __unused)
518 {
519 	struct timespec ts;
520 	struct proc *p;
521 	struct rusage ru;
522 	struct thread *td;
523 
524 	/*
525 	 * Now we can look at the time, having had a chance to verify the
526 	 * time from the filesystem.  Pretend that proc0 started now.
527 	 */
528 	sx_slock(&allproc_lock);
529 	FOREACH_PROC_IN_SYSTEM(p) {
530 		microuptime(&p->p_stats->p_start);
531 		PROC_SLOCK(p);
532 		rufetch(p, &ru);	/* Clears thread stats */
533 		PROC_SUNLOCK(p);
534 		p->p_rux.rux_runtime = 0;
535 		p->p_rux.rux_uticks = 0;
536 		p->p_rux.rux_sticks = 0;
537 		p->p_rux.rux_iticks = 0;
538 		FOREACH_THREAD_IN_PROC(p, td) {
539 			td->td_runtime = 0;
540 		}
541 	}
542 	sx_sunlock(&allproc_lock);
543 	PCPU_SET(switchtime, cpu_ticks());
544 	PCPU_SET(switchticks, ticks);
545 
546 	/*
547 	 * Give the ``random'' number generator a thump.
548 	 */
549 	nanotime(&ts);
550 	srandom(ts.tv_sec ^ ts.tv_nsec);
551 }
552 SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL);
553 
554 /*
555  ***************************************************************************
556  ****
557  **** The following SYSINIT's and glue code should be moved to the
558  **** respective files on a per subsystem basis.
559  ****
560  ***************************************************************************
561  */
562 
563 
564 /*
565  ***************************************************************************
566  ****
567  **** The following code probably belongs in another file, like
568  **** kern/init_init.c.
569  ****
570  ***************************************************************************
571  */
572 
573 /*
574  * List of paths to try when searching for "init".
575  */
576 static char init_path[MAXPATHLEN] =
577 #ifdef	INIT_PATH
578     __XSTRING(INIT_PATH);
579 #else
580     "/sbin/init:/sbin/oinit:/sbin/init.bak:/rescue/init:/stand/sysinstall";
581 #endif
582 SYSCTL_STRING(_kern, OID_AUTO, init_path, CTLFLAG_RD, init_path, 0,
583 	"Path used to search the init process");
584 
585 /*
586  * Shutdown timeout of init(8).
587  * Unused within kernel, but used to control init(8), hence do not remove.
588  */
589 #ifndef INIT_SHUTDOWN_TIMEOUT
590 #define INIT_SHUTDOWN_TIMEOUT 120
591 #endif
592 static int init_shutdown_timeout = INIT_SHUTDOWN_TIMEOUT;
593 SYSCTL_INT(_kern, OID_AUTO, init_shutdown_timeout,
594 	CTLFLAG_RW, &init_shutdown_timeout, 0, "");
595 
596 /*
597  * Start the initial user process; try exec'ing each pathname in init_path.
598  * The program is invoked with one argument containing the boot flags.
599  */
600 static void
601 start_init(void *dummy)
602 {
603 	vm_offset_t addr;
604 	struct execve_args args;
605 	int options, error;
606 	char *var, *path, *next, *s;
607 	char *ucp, **uap, *arg0, *arg1;
608 	struct thread *td;
609 	struct proc *p;
610 
611 	mtx_lock(&Giant);
612 
613 	GIANT_REQUIRED;
614 
615 	td = curthread;
616 	p = td->td_proc;
617 
618 	vfs_mountroot();
619 
620 	/*
621 	 * Need just enough stack to hold the faked-up "execve()" arguments.
622 	 */
623 	addr = p->p_sysent->sv_usrstack - PAGE_SIZE;
624 	if (vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, PAGE_SIZE,
625 			FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != 0)
626 		panic("init: couldn't allocate argument space");
627 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
628 	p->p_vmspace->vm_ssize = 1;
629 
630 	if ((var = getenv("init_path")) != NULL) {
631 		strlcpy(init_path, var, sizeof(init_path));
632 		freeenv(var);
633 	}
634 
635 	for (path = init_path; *path != '\0'; path = next) {
636 		while (*path == ':')
637 			path++;
638 		if (*path == '\0')
639 			break;
640 		for (next = path; *next != '\0' && *next != ':'; next++)
641 			/* nothing */ ;
642 		if (bootverbose)
643 			printf("start_init: trying %.*s\n", (int)(next - path),
644 			    path);
645 
646 		/*
647 		 * Move out the boot flag argument.
648 		 */
649 		options = 0;
650 		ucp = (char *)p->p_sysent->sv_usrstack;
651 		(void)subyte(--ucp, 0);		/* trailing zero */
652 		if (boothowto & RB_SINGLE) {
653 			(void)subyte(--ucp, 's');
654 			options = 1;
655 		}
656 #ifdef notyet
657                 if (boothowto & RB_FASTBOOT) {
658 			(void)subyte(--ucp, 'f');
659 			options = 1;
660 		}
661 #endif
662 
663 #ifdef BOOTCDROM
664 		(void)subyte(--ucp, 'C');
665 		options = 1;
666 #endif
667 
668 		if (options == 0)
669 			(void)subyte(--ucp, '-');
670 		(void)subyte(--ucp, '-');		/* leading hyphen */
671 		arg1 = ucp;
672 
673 		/*
674 		 * Move out the file name (also arg 0).
675 		 */
676 		(void)subyte(--ucp, 0);
677 		for (s = next - 1; s >= path; s--)
678 			(void)subyte(--ucp, *s);
679 		arg0 = ucp;
680 
681 		/*
682 		 * Move out the arg pointers.
683 		 */
684 		uap = (char **)((intptr_t)ucp & ~(sizeof(intptr_t)-1));
685 		(void)suword((caddr_t)--uap, (long)0);	/* terminator */
686 		(void)suword((caddr_t)--uap, (long)(intptr_t)arg1);
687 		(void)suword((caddr_t)--uap, (long)(intptr_t)arg0);
688 
689 		/*
690 		 * Point at the arguments.
691 		 */
692 		args.fname = arg0;
693 		args.argv = uap;
694 		args.envv = NULL;
695 
696 		/*
697 		 * Now try to exec the program.  If can't for any reason
698 		 * other than it doesn't exist, complain.
699 		 *
700 		 * Otherwise, return via fork_trampoline() all the way
701 		 * to user mode as init!
702 		 */
703 		if ((error = execve(td, &args)) == 0) {
704 			mtx_unlock(&Giant);
705 			return;
706 		}
707 		if (error != ENOENT)
708 			printf("exec %.*s: error %d\n", (int)(next - path),
709 			    path, error);
710 	}
711 	printf("init: not found in path %s\n", init_path);
712 	panic("no init");
713 }
714 
715 /*
716  * Like kproc_create(), but runs in it's own address space.
717  * We do this early to reserve pid 1.
718  *
719  * Note special case - do not make it runnable yet.  Other work
720  * in progress will change this more.
721  */
722 static void
723 create_init(const void *udata __unused)
724 {
725 	struct ucred *newcred, *oldcred;
726 	int error;
727 
728 	error = fork1(&thread0, RFFDG | RFPROC | RFSTOPPED, 0, &initproc);
729 	if (error)
730 		panic("cannot fork init: %d\n", error);
731 	KASSERT(initproc->p_pid == 1, ("create_init: initproc->p_pid != 1"));
732 	/* divorce init's credentials from the kernel's */
733 	newcred = crget();
734 	PROC_LOCK(initproc);
735 	initproc->p_flag |= P_SYSTEM | P_INMEM;
736 	oldcred = initproc->p_ucred;
737 	crcopy(newcred, oldcred);
738 #ifdef MAC
739 	mac_cred_create_init(newcred);
740 #endif
741 #ifdef AUDIT
742 	audit_cred_proc1(newcred);
743 #endif
744 	initproc->p_ucred = newcred;
745 	PROC_UNLOCK(initproc);
746 	crfree(oldcred);
747 	cred_update_thread(FIRST_THREAD_IN_PROC(initproc));
748 	cpu_set_fork_handler(FIRST_THREAD_IN_PROC(initproc), start_init, NULL);
749 }
750 SYSINIT(init, SI_SUB_CREATE_INIT, SI_ORDER_FIRST, create_init, NULL);
751 
752 /*
753  * Make it runnable now.
754  */
755 static void
756 kick_init(const void *udata __unused)
757 {
758 	struct thread *td;
759 
760 	td = FIRST_THREAD_IN_PROC(initproc);
761 	thread_lock(td);
762 	TD_SET_CAN_RUN(td);
763 	sched_add(td, SRQ_BORING);
764 	thread_unlock(td);
765 }
766 SYSINIT(kickinit, SI_SUB_KTHREAD_INIT, SI_ORDER_FIRST, kick_init, NULL);
767