xref: /netbsd-src/sys/kern/init_main.c (revision 001c68bd94f75ce9270b69227c4199fbf34ee396)
1 /*	$NetBSD: init_main.c,v 1.221 2003/06/29 22:31:17 fvdl Exp $	*/
2 
3 /*
4  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
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	8.16 (Berkeley) 5/14/95
42  */
43 
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.221 2003/06/29 22:31:17 fvdl Exp $");
46 
47 #include "fs_nfs.h"
48 #include "opt_nfsserver.h"
49 #include "opt_sysv.h"
50 #include "opt_maxuprc.h"
51 #include "opt_multiprocessor.h"
52 #include "opt_pipe.h"
53 #include "opt_syscall_debug.h"
54 #include "opt_systrace.h"
55 #include "opt_posix.h"
56 
57 #include "rnd.h"
58 
59 #include <sys/param.h>
60 #include <sys/acct.h>
61 #include <sys/filedesc.h>
62 #include <sys/file.h>
63 #include <sys/errno.h>
64 #include <sys/callout.h>
65 #include <sys/kernel.h>
66 #include <sys/mount.h>
67 #include <sys/proc.h>
68 #include <sys/kthread.h>
69 #include <sys/resourcevar.h>
70 #include <sys/signalvar.h>
71 #include <sys/systm.h>
72 #include <sys/vnode.h>
73 #include <sys/tty.h>
74 #include <sys/conf.h>
75 #include <sys/disklabel.h>
76 #include <sys/buf.h>
77 #include <sys/device.h>
78 #include <sys/disk.h>
79 #include <sys/exec.h>
80 #include <sys/socketvar.h>
81 #include <sys/protosw.h>
82 #include <sys/reboot.h>
83 #include <sys/user.h>
84 #include <sys/sysctl.h>
85 #include <sys/event.h>
86 #ifdef SYSVSHM
87 #include <sys/shm.h>
88 #endif
89 #ifdef SYSVSEM
90 #include <sys/sem.h>
91 #endif
92 #ifdef SYSVMSG
93 #include <sys/msg.h>
94 #endif
95 #ifdef P1003_1B_SEMAPHORE
96 #include <sys/ksem.h>
97 #endif
98 #ifdef SYSTRACE
99 #include <sys/systrace.h>
100 #endif
101 #include <sys/domain.h>
102 #include <sys/mbuf.h>
103 #include <sys/namei.h>
104 #if NRND > 0
105 #include <sys/rnd.h>
106 #endif
107 #ifndef PIPE_SOCKETPAIR
108 #include <sys/pipe.h>
109 #endif
110 #ifdef LKM
111 #include <sys/lkm.h>
112 #endif
113 
114 #include <sys/syscall.h>
115 #include <sys/sa.h>
116 #include <sys/syscallargs.h>
117 
118 #include <ufs/ufs/quota.h>
119 
120 #include <miscfs/genfs/genfs.h>
121 #include <miscfs/syncfs/syncfs.h>
122 
123 #include <machine/cpu.h>
124 
125 #include <uvm/uvm.h>
126 
127 #include <dev/cons.h>
128 
129 #include <net/if.h>
130 #include <net/raw_cb.h>
131 
132 const char copyright[] =
133 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003\n"
134 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
135 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
136 "    The Regents of the University of California.  All rights reserved.\n"
137 "\n";
138 
139 /* Components of the first process -- never freed. */
140 struct	session session0;
141 struct	pgrp pgrp0;
142 struct	proc proc0;
143 struct	lwp lwp0;
144 struct	pcred cred0;
145 struct	filedesc0 filedesc0;
146 struct	cwdinfo cwdi0;
147 struct	plimit limit0;
148 struct	pstats pstat0;
149 struct	vmspace vmspace0;
150 struct	sigacts sigacts0;
151 #ifndef curlwp
152 struct	lwp *curlwp = &lwp0;
153 #endif
154 struct	proc *initproc;
155 
156 int	nofile = NOFILE;
157 int	maxuprc = MAXUPRC;
158 int	cmask = CMASK;
159 extern	struct user *proc0paddr;
160 
161 struct	vnode *rootvp, *swapdev_vp;
162 int	boothowto;
163 int	cold = 1;			/* still working on startup */
164 struct	timeval boottime;
165 
166 __volatile int start_init_exec;		/* semaphore for start_init() */
167 
168 static void check_console(struct proc *p);
169 static void start_init(void *);
170 void main(void);
171 
172 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
173 
174 /*
175  * System startup; initialize the world, create process 0, mount root
176  * filesystem, and fork to create init and pagedaemon.  Most of the
177  * hard work is done in the lower-level initialization routines including
178  * startup(), which does memory initialization and autoconfiguration.
179  */
180 void
181 main(void)
182 {
183 	struct lwp *l;
184 	struct proc *p;
185 	struct pdevinit *pdev;
186 	int s, error;
187 	u_int i;
188 	rlim_t lim;
189 	extern struct pdevinit pdevinit[];
190 	extern void schedcpu(void *);
191 #if defined(NFSSERVER) || defined(NFS)
192 	extern void nfs_init(void);
193 #endif
194 #ifdef NVNODE_IMPLICIT
195 	int usevnodes;
196 #endif
197 
198 	/*
199 	 * Initialize the current LWP pointer (curlwp) before
200 	 * any possible traps/probes to simplify trap processing.
201 	 */
202 	simple_lock_init(&proc0.p_raslock);
203 	l = &lwp0;
204 	curlwp = l;
205 	l->l_cpu = curcpu();
206 	l->l_proc = &proc0;
207 	l->l_lid = 1;
208 	/*
209 	 * Attempt to find console and initialize
210 	 * in case of early panic or other messages.
211 	 */
212 	consinit();
213 	printf("%s", copyright);
214 
215 	KERNEL_LOCK_INIT();
216 
217 	uvm_init();
218 
219 	/* Do machine-dependent initialization. */
220 	cpu_startup();
221 
222 	/* Initialize callouts. */
223 	callout_startup();
224 
225 	/*
226 	 * Initialize mbuf's.  Do this now because we might attempt to
227 	 * allocate mbufs or mbuf clusters during autoconfiguration.
228 	 */
229 	mbinit();
230 
231 	/* Initialize kqueues. */
232 	kqueue_init();
233 
234 	/* Initialize sockets. */
235 	soinit();
236 
237 	/*
238 	 * The following things must be done before autoconfiguration.
239 	 */
240 	evcnt_init();		/* initialize event counters */
241 	disk_init();		/* initialize disk list */
242 	tty_init();		/* initialize tty list */
243 #if NRND > 0
244 	rnd_init();		/* initialize RNG */
245 #endif
246 
247 	/* Initialize the sysctl subsystem. */
248 	sysctl_init();
249 
250 	/*
251 	 * Initialize process and pgrp structures.
252 	 */
253 	procinit();
254 
255 #ifdef LKM
256 	/* Initialize the LKM system. */
257 	lkm_init();
258 #endif
259 
260 	/*
261 	 * Create process 0 (the swapper).
262 	 */
263 	p = &proc0;
264 	proc0_insert(p, l, &pgrp0, &session0);
265 
266 	/*
267 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
268 	 * init(8) when they exit.  init(8) can easily wait them out
269 	 * for us.
270 	 */
271 	p->p_flag = P_SYSTEM | P_NOCLDWAIT;
272 	p->p_stat = SACTIVE;
273 	p->p_nice = NZERO;
274 	p->p_emul = &emul_netbsd;
275 #ifdef __HAVE_SYSCALL_INTERN
276 	(*p->p_emul->e_syscall_intern)(p);
277 #endif
278 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
279 
280 	l->l_flag = L_INMEM;
281 	l->l_stat = LSONPROC;
282 	p->p_nrlwps = 1;
283 
284 	callout_init(&l->l_tsleep_ch);
285 
286 	/* Create credentials. */
287 	cred0.p_refcnt = 1;
288 	p->p_cred = &cred0;
289 	p->p_ucred = crget();
290 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
291 
292 	/* Create the file descriptor table. */
293 	finit();
294 	p->p_fd = &filedesc0.fd_fd;
295 	fdinit1(&filedesc0);
296 
297 	/* Create the CWD info. */
298 	p->p_cwdi = &cwdi0;
299 	cwdi0.cwdi_cmask = cmask;
300 	cwdi0.cwdi_refcnt = 1;
301 
302 	/* Create the limits structures. */
303 	p->p_limit = &limit0;
304 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
305 		limit0.pl_rlimit[i].rlim_cur =
306 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
307 
308 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
309 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
310 	    maxfiles < nofile ? maxfiles : nofile;
311 
312 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
313 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
314 	    maxproc < maxuprc ? maxproc : maxuprc;
315 
316 	lim = ptoa(uvmexp.free);
317 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
318 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
319 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
320 	limit0.pl_corename = defcorename;
321 	limit0.p_refcnt = 1;
322 
323 	/*
324 	 * Initialize proc0's vmspace, which uses the kernel pmap.
325 	 * All kernel processes (which never have user space mappings)
326 	 * share proc0's vmspace, and thus, the kernel pmap.
327 	 */
328 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
329 	    trunc_page(VM_MAX_ADDRESS));
330 	p->p_vmspace = &vmspace0;
331 
332 	l->l_addr = proc0paddr;				/* XXX */
333 
334 	p->p_stats = &pstat0;
335 
336 	/*
337 	 * Charge root for one process.
338 	 */
339 	(void)chgproccnt(0, 1);
340 
341 	rqinit();
342 
343 	/* Configure virtual memory system, set vm rlimits. */
344 	uvm_init_limits(p);
345 
346 	/* Initialize the file systems. */
347 #if defined(NFSSERVER) || defined(NFS)
348 	nfs_init();			/* initialize server/shared data */
349 #endif
350 #ifdef NVNODE_IMPLICIT
351 	/*
352 	 * If maximum number of vnodes in namei vnode cache is not explicitly
353 	 * defined in kernel config, adjust the number such as we use roughly
354 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
355 	 */
356 	usevnodes = (ptoa((unsigned)physmem) / 200) / sizeof(struct vnode);
357 	if (usevnodes > desiredvnodes)
358 		desiredvnodes = usevnodes;
359 #endif
360 	vfsinit();
361 
362 	/* Configure the system hardware.  This will enable interrupts. */
363 	configure();
364 
365 	ubc_init();		/* must be after autoconfig */
366 
367 	/* Lock the kernel on behalf of proc0. */
368 	KERNEL_PROC_LOCK(l);
369 
370 #ifdef SYSVSHM
371 	/* Initialize System V style shared memory. */
372 	shminit();
373 #endif
374 
375 #ifdef SYSVSEM
376 	/* Initialize System V style semaphores. */
377 	seminit();
378 #endif
379 
380 #ifdef SYSVMSG
381 	/* Initialize System V style message queues. */
382 	msginit();
383 #endif
384 
385 
386 #ifdef P1003_1B_SEMAPHORE
387 	/* Initialize posix semaphores */
388 	ksem_init();
389 #endif
390 	/* Attach pseudo-devices. */
391 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
392 		(*pdev->pdev_attach)(pdev->pdev_count);
393 
394 	/*
395 	 * Initialize protocols.  Block reception of incoming packets
396 	 * until everything is ready.
397 	 */
398 	s = splnet();
399 	ifinit();
400 	domaininit();
401 	if_attachdomain();
402 	splx(s);
403 
404 #ifdef GPROF
405 	/* Initialize kernel profiling. */
406 	kmstartup();
407 #endif
408 
409 	/* Initialize system accouting. */
410 	acct_init();
411 
412 #ifdef SYSTRACE
413 	systrace_init();
414 #endif
415 	/*
416 	 * Initialize signal-related data structures, and signal state
417 	 * for proc0.
418 	 */
419 	signal_init();
420 	p->p_sigacts = &sigacts0;
421 	siginit(p);
422 
423 	/* Kick off timeout driven events by calling first time. */
424 	schedcpu(NULL);
425 
426 	/*
427 	 * Create process 1 (init(8)).  We do this now, as Unix has
428 	 * historically had init be process 1, and changing this would
429 	 * probably upset a lot of people.
430 	 *
431 	 * Note that process 1 won't immediately exec init(8), but will
432 	 * wait for us to inform it that the root file system has been
433 	 * mounted.
434 	 */
435 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
436 		panic("fork init");
437 
438 	/*
439 	 * Create any kernel threads who's creation was deferred because
440 	 * initproc had not yet been created.
441 	 */
442 	kthread_run_deferred_queue();
443 
444 	/*
445 	 * Now that device driver threads have been created, wait for
446 	 * them to finish any deferred autoconfiguration.  Note we don't
447 	 * need to lock this semaphore, since we haven't booted any
448 	 * secondary processors, yet.
449 	 */
450 	while (config_pending)
451 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
452 
453 	/*
454 	 * Finalize configuration now that all real devices have been
455 	 * found.  This needs to be done before the root device is
456 	 * selected, since finalization may create the root device.
457 	 */
458 	config_finalize();
459 
460 	/*
461 	 * Now that autoconfiguration has completed, we can determine
462 	 * the root and dump devices.
463 	 */
464 	cpu_rootconf();
465 	cpu_dumpconf();
466 
467 	/* Mount the root file system. */
468 	do {
469 		domountroothook();
470 		if ((error = vfs_mountroot())) {
471 			printf("cannot mount root, error = %d\n", error);
472 			boothowto |= RB_ASKNAME;
473 			setroot(root_device,
474 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
475 		}
476 	} while (error != 0);
477 	mountroothook_destroy();
478 
479 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
480 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
481 
482 	/*
483 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
484 	 * reference it.
485 	 */
486 	if (VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode))
487 		panic("cannot find root vnode");
488 	cwdi0.cwdi_cdir = rootvnode;
489 	VREF(cwdi0.cwdi_cdir);
490 	VOP_UNLOCK(rootvnode, 0);
491 	cwdi0.cwdi_rdir = NULL;
492 
493 	/*
494 	 * Now that root is mounted, we can fixup initproc's CWD
495 	 * info.  All other processes are kthreads, which merely
496 	 * share proc0's CWD info.
497 	 */
498 	initproc->p_cwdi->cwdi_cdir = rootvnode;
499 	VREF(initproc->p_cwdi->cwdi_cdir);
500 	initproc->p_cwdi->cwdi_rdir = NULL;
501 
502 	/*
503 	 * Now can look at time, having had a chance to verify the time
504 	 * from the file system.  Reset p->p_rtime as it may have been
505 	 * munched in mi_switch() after the time got set.
506 	 */
507 	proclist_lock_read();
508 	s = splsched();
509 	for (p = LIST_FIRST(&allproc); p != NULL;
510 	     p = LIST_NEXT(p, p_list)) {
511 		p->p_stats->p_start = mono_time = boottime = time;
512 		for (l = LIST_FIRST(&p->p_lwps); l != NULL;
513 		     l = LIST_NEXT(l, l_sibling))
514 			if (l->l_cpu != NULL)
515 				l->l_cpu->ci_schedstate.spc_runtime = time;
516 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
517 	}
518 	splx(s);
519 	proclist_unlock_read();
520 
521 	/* Create the pageout daemon kernel thread. */
522 	uvm_swap_init();
523 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
524 		panic("fork pagedaemon");
525 
526 	/* Create the process reaper kernel thread. */
527 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
528 		panic("fork reaper");
529 
530 	/* Create the filesystem syncer kernel thread. */
531 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
532 		panic("fork syncer");
533 
534 	/* Create the aiodone daemon kernel thread. */
535 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
536 	    "aiodoned"))
537 		panic("fork aiodoned");
538 
539 #if defined(MULTIPROCESSOR)
540 	/* Boot the secondary processors. */
541 	cpu_boot_secondary_processors();
542 #endif
543 
544 	/* Initialize exec structures */
545 	exec_init(1);
546 
547 #ifndef PIPE_SOCKETPAIR
548 	/* Initialize pipe structures */
549 	pipe_init();
550 #endif
551 
552 	/*
553 	 * Okay, now we can let init(8) exec!  It's off to userland!
554 	 */
555 	start_init_exec = 1;
556 	wakeup((void *)&start_init_exec);
557 
558 	/* The scheduler is an infinite loop. */
559 	uvm_scheduler();
560 	/* NOTREACHED */
561 }
562 
563 static void
564 check_console(struct proc *p)
565 {
566 	struct nameidata nd;
567 	int error;
568 
569 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
570 	error = namei(&nd);
571 	if (error == 0)
572 		vrele(nd.ni_vp);
573 	else if (error == ENOENT)
574 		printf("warning: no /dev/console\n");
575 	else
576 		printf("warning: lookup /dev/console: error %d\n", error);
577 }
578 
579 /*
580  * List of paths to try when searching for "init".
581  */
582 static const char *initpaths[] = {
583 	"/sbin/init",
584 	"/sbin/oinit",
585 	"/sbin/init.bak",
586 	NULL,
587 };
588 
589 /*
590  * Start the initial user process; try exec'ing each pathname in "initpaths".
591  * The program is invoked with one argument containing the boot flags.
592  */
593 static void
594 start_init(void *arg)
595 {
596 	struct lwp *l = arg;
597 	struct proc *p = l->l_proc;
598 	vaddr_t addr;
599 	struct sys_execve_args /* {
600 		syscallarg(const char *) path;
601 		syscallarg(char * const *) argp;
602 		syscallarg(char * const *) envp;
603 	} */ args;
604 	int options, i, error;
605 	register_t retval[2];
606 	char flags[4], *flagsp;
607 	const char *path, *slash;
608 	char *ucp, **uap, *arg0, *arg1 = NULL;
609 	char ipath[129];
610 	int ipx, len;
611 
612 	/*
613 	 * Now in process 1.
614 	 */
615 	strncpy(p->p_comm, "init", MAXCOMLEN);
616 
617 	/*
618 	 * Wait for main() to tell us that it's safe to exec.
619 	 */
620 	while (start_init_exec == 0)
621 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
622 
623 	/*
624 	 * This is not the right way to do this.  We really should
625 	 * hand-craft a descriptor onto /dev/console to hand to init,
626 	 * but that's a _lot_ more work, and the benefit from this easy
627 	 * hack makes up for the "good is the enemy of the best" effect.
628 	 */
629 	check_console(p);
630 
631 	/*
632 	 * Need just enough stack to hold the faked-up "execve()" arguments.
633 	 */
634 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
635 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
636                     NULL, UVM_UNKNOWN_OFFSET, 0,
637                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
638 		    UVM_ADV_NORMAL,
639                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
640 		panic("init: couldn't allocate argument space");
641 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
642 
643 	ipx = 0;
644 	while (1) {
645 		if (boothowto & RB_ASKNAME) {
646 			printf("init path");
647 			if (initpaths[ipx])
648 				printf(" (default %s)", initpaths[ipx]);
649 			printf(": ");
650 			len = cngetsn(ipath, sizeof(ipath)-1);
651 			if (len == 0) {
652 				if (initpaths[ipx])
653 					path = initpaths[ipx++];
654 				else
655 					continue;
656 			} else {
657 				ipath[len] = '\0';
658 				path = ipath;
659 			}
660 		} else {
661 			if ((path = initpaths[ipx++]) == NULL)
662 				break;
663 		}
664 
665 		ucp = (char *)USRSTACK;
666 
667 		/*
668 		 * Construct the boot flag argument.
669 		 */
670 		flagsp = flags;
671 		*flagsp++ = '-';
672 		options = 0;
673 
674 		if (boothowto & RB_SINGLE) {
675 			*flagsp++ = 's';
676 			options = 1;
677 		}
678 #ifdef notyet
679 		if (boothowto & RB_FASTBOOT) {
680 			*flagsp++ = 'f';
681 			options = 1;
682 		}
683 #endif
684 
685 		/*
686 		 * Move out the flags (arg 1), if necessary.
687 		 */
688 		if (options != 0) {
689 			*flagsp++ = '\0';
690 			i = flagsp - flags;
691 #ifdef DEBUG
692 			printf("init: copying out flags `%s' %d\n", flags, i);
693 #endif
694 			arg1 = STACK_ALLOC(ucp, i);
695 			ucp = STACK_MAX(arg1, i);
696 			(void)copyout((caddr_t)flags, arg1, i);
697 		}
698 
699 		/*
700 		 * Move out the file name (also arg 0).
701 		 */
702 		i = strlen(path) + 1;
703 #ifdef DEBUG
704 		printf("init: copying out path `%s' %d\n", path, i);
705 #else
706 		if (boothowto & RB_ASKNAME || path != initpaths[0])
707 			printf("init: trying %s\n", path);
708 #endif
709 		arg0 = STACK_ALLOC(ucp, i);
710 		ucp = STACK_MAX(arg0, i);
711 		(void)copyout((caddr_t)path, arg0, i);
712 
713 		/*
714 		 * Move out the arg pointers.
715 		 */
716 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
717 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
718 		SCARG(&args, path) = arg0;
719 		SCARG(&args, argp) = uap;
720 		SCARG(&args, envp) = NULL;
721 		slash = strrchr(path, '/');
722 		if (slash)
723 			(void)suword((caddr_t)uap++,
724 			    (long)arg0 + (slash + 1 - path));
725 		else
726 			(void)suword((caddr_t)uap++, (long)arg0);
727 		if (options != 0)
728 			(void)suword((caddr_t)uap++, (long)arg1);
729 		(void)suword((caddr_t)uap++, 0);	/* terminator */
730 
731 		/*
732 		 * Now try to exec the program.  If can't for any reason
733 		 * other than it doesn't exist, complain.
734 		 */
735 		error = sys_execve(LIST_FIRST(&p->p_lwps), &args, retval);
736 		if (error == 0 || error == EJUSTRETURN) {
737 			KERNEL_PROC_UNLOCK(l);
738 			return;
739 		}
740 		printf("exec %s: error %d\n", path, error);
741 	}
742 	printf("init: not found\n");
743 	panic("no init");
744 }
745