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init_main.c revision 1.191
      1 /*	$NetBSD: init_main.c,v 1.191 2001/06/08 12:53:30 mrg 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 "fs_nfs.h"
     45 #include "opt_nfsserver.h"
     46 #include "opt_sysv.h"
     47 #include "opt_maxuprc.h"
     48 #include "opt_multiprocessor.h"
     49 #include "opt_syscall_debug.h"
     50 
     51 #include "rnd.h"
     52 
     53 #include <sys/param.h>
     54 #include <sys/acct.h>
     55 #include <sys/filedesc.h>
     56 #include <sys/file.h>
     57 #include <sys/errno.h>
     58 #include <sys/callout.h>
     59 #include <sys/kernel.h>
     60 #include <sys/mount.h>
     61 #include <sys/map.h>
     62 #include <sys/proc.h>
     63 #include <sys/kthread.h>
     64 #include <sys/resourcevar.h>
     65 #include <sys/signalvar.h>
     66 #include <sys/systm.h>
     67 #include <sys/vnode.h>
     68 #include <sys/tty.h>
     69 #include <sys/conf.h>
     70 #include <sys/disklabel.h>
     71 #include <sys/buf.h>
     72 #include <sys/device.h>
     73 #include <sys/exec.h>
     74 #include <sys/socketvar.h>
     75 #include <sys/protosw.h>
     76 #include <sys/reboot.h>
     77 #include <sys/user.h>
     78 #include <sys/sysctl.h>
     79 #ifdef SYSVSHM
     80 #include <sys/shm.h>
     81 #endif
     82 #ifdef SYSVSEM
     83 #include <sys/sem.h>
     84 #endif
     85 #ifdef SYSVMSG
     86 #include <sys/msg.h>
     87 #endif
     88 #include <sys/domain.h>
     89 #include <sys/mbuf.h>
     90 #include <sys/namei.h>
     91 #if NRND > 0
     92 #include <sys/rnd.h>
     93 #endif
     94 
     95 #include <sys/syscall.h>
     96 #include <sys/syscallargs.h>
     97 
     98 #include <ufs/ufs/quota.h>
     99 
    100 #include <miscfs/genfs/genfs.h>
    101 #include <miscfs/syncfs/syncfs.h>
    102 
    103 #include <machine/cpu.h>
    104 
    105 #include <uvm/uvm.h>
    106 
    107 #include <net/if.h>
    108 #include <net/raw_cb.h>
    109 
    110 const char copyright[] = "\n"
    111 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001\n"
    112 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
    113 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
    114 "    The Regents of the University of California.  All rights reserved.\n"
    115 "\n";
    116 
    117 /* Components of the first process -- never freed. */
    118 struct	session session0;
    119 struct	pgrp pgrp0;
    120 struct	proc proc0;
    121 struct	pcred cred0;
    122 struct	filedesc0 filedesc0;
    123 struct	cwdinfo cwdi0;
    124 struct	plimit limit0;
    125 struct	vmspace vmspace0;
    126 struct	sigacts sigacts0;
    127 #ifndef curproc
    128 struct	proc *curproc = &proc0;
    129 #endif
    130 struct	proc *initproc;
    131 
    132 int	cmask = CMASK;
    133 extern	struct user *proc0paddr;
    134 
    135 struct	vnode *rootvp, *swapdev_vp;
    136 int	boothowto;
    137 int	cold = 1;			/* still working on startup */
    138 struct	timeval boottime;
    139 
    140 __volatile int start_init_exec;		/* semaphore for start_init() */
    141 
    142 static void check_console(struct proc *p);
    143 static void start_init(void *);
    144 void main(void);
    145 
    146 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
    147 
    148 /*
    149  * System startup; initialize the world, create process 0, mount root
    150  * filesystem, and fork to create init and pagedaemon.  Most of the
    151  * hard work is done in the lower-level initialization routines including
    152  * startup(), which does memory initialization and autoconfiguration.
    153  */
    154 void
    155 main(void)
    156 {
    157 	struct proc *p;
    158 	struct pdevinit *pdev;
    159 	int i, s, error;
    160 	rlim_t lim;
    161 	extern struct pdevinit pdevinit[];
    162 	extern void schedcpu(void *);
    163 	extern void disk_init(void);
    164 #if defined(NFSSERVER) || defined(NFS)
    165 	extern void nfs_init(void);
    166 #endif
    167 #ifdef NVNODE_IMPLICIT
    168 	int usevnodes;
    169 #endif
    170 
    171 	/*
    172 	 * Initialize the current process pointer (curproc) before
    173 	 * any possible traps/probes to simplify trap processing.
    174 	 */
    175 	p = &proc0;
    176 	curproc = p;
    177 	p->p_cpu = curcpu();
    178 	/*
    179 	 * Attempt to find console and initialize
    180 	 * in case of early panic or other messages.
    181 	 */
    182 	consinit();
    183 	printf("%s", copyright);
    184 
    185 	KERNEL_LOCK_INIT();
    186 
    187 	uvm_init();
    188 
    189 	/* Do machine-dependent initialization. */
    190 	cpu_startup();
    191 
    192 	/* Initialize callouts. */
    193 	callout_startup();
    194 
    195 	/*
    196 	 * Initialize mbuf's.  Do this now because we might attempt to
    197 	 * allocate mbufs or mbuf clusters during autoconfiguration.
    198 	 */
    199 	mbinit();
    200 
    201 	/* Initialize sockets. */
    202 	soinit();
    203 
    204 	/*
    205 	 * The following 3 things must be done before autoconfiguration.
    206 	 */
    207 	disk_init();		/* initialize disk list */
    208 	tty_init();		/* initialize tty list */
    209 #if NRND > 0
    210 	rnd_init();		/* initialize RNG */
    211 #endif
    212 
    213 	/* Initialize the sysctl subsystem. */
    214 	sysctl_init();
    215 
    216 	/*
    217 	 * Initialize process and pgrp structures.
    218 	 */
    219 	procinit();
    220 
    221 	/*
    222 	 * Create process 0 (the swapper).
    223 	 */
    224 	s = proclist_lock_write();
    225 	LIST_INSERT_HEAD(&allproc, p, p_list);
    226 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
    227 	proclist_unlock_write(s);
    228 
    229 	p->p_pgrp = &pgrp0;
    230 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
    231 	LIST_INIT(&pgrp0.pg_members);
    232 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
    233 
    234 	pgrp0.pg_session = &session0;
    235 	session0.s_count = 1;
    236 	session0.s_sid = p->p_pid;
    237 	session0.s_leader = p;
    238 
    239 	/*
    240 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
    241 	 * init(8) when they exit.  init(8) can easily wait them out
    242 	 * for us.
    243 	 */
    244 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
    245 	p->p_stat = SONPROC;
    246 	p->p_nice = NZERO;
    247 	p->p_emul = &emul_netbsd;
    248 #ifdef __HAVE_SYSCALL_INTERN
    249 	(*p->p_emul->e_syscall_intern)(p);
    250 #endif
    251 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
    252 
    253 	callout_init(&p->p_realit_ch);
    254 	callout_init(&p->p_tsleep_ch);
    255 
    256 	/* Create credentials. */
    257 	cred0.p_refcnt = 1;
    258 	p->p_cred = &cred0;
    259 	p->p_ucred = crget();
    260 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
    261 
    262 	/* Create the file descriptor table. */
    263 	finit();
    264 	p->p_fd = &filedesc0.fd_fd;
    265 	fdinit1(&filedesc0);
    266 
    267 	/* Create the CWD info. */
    268 	p->p_cwdi = &cwdi0;
    269 	cwdi0.cwdi_cmask = cmask;
    270 	cwdi0.cwdi_refcnt = 1;
    271 
    272 	/* Create the limits structures. */
    273 	p->p_limit = &limit0;
    274 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
    275 		limit0.pl_rlimit[i].rlim_cur =
    276 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
    277 
    278 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
    279 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
    280 	    maxfiles < NOFILE ? maxfiles : NOFILE;
    281 
    282 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
    283 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
    284 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
    285 
    286 	lim = ptoa(uvmexp.free);
    287 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
    288 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
    289 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
    290 	limit0.pl_corename = defcorename;
    291 	limit0.p_refcnt = 1;
    292 
    293 	/*
    294 	 * Initialize proc0's vmspace, which uses the kernel pmap.
    295 	 * All kernel processes (which never have user space mappings)
    296 	 * share proc0's vmspace, and thus, the kernel pmap.
    297 	 */
    298 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
    299 	    trunc_page(VM_MAX_ADDRESS), TRUE);
    300 	p->p_vmspace = &vmspace0;
    301 
    302 	p->p_addr = proc0paddr;				/* XXX */
    303 
    304 	/*
    305 	 * We continue to place resource usage info in the
    306 	 * user struct so they're pageable.
    307 	 */
    308 	p->p_stats = &p->p_addr->u_stats;
    309 
    310 	/*
    311 	 * Charge root for one process.
    312 	 */
    313 	(void)chgproccnt(0, 1);
    314 
    315 	rqinit();
    316 
    317 	/* Configure virtual memory system, set vm rlimits. */
    318 	uvm_init_limits(p);
    319 
    320 	/* Initialize the file systems. */
    321 #if defined(NFSSERVER) || defined(NFS)
    322 	nfs_init();			/* initialize server/shared data */
    323 #endif
    324 	vfsinit();
    325 
    326 	/* Configure the system hardware.  This will enable interrupts. */
    327 	configure();
    328 
    329 	ubc_init();		/* must be after autoconfig */
    330 
    331 	/* Lock the kernel on behalf of proc0. */
    332 	KERNEL_PROC_LOCK(p);
    333 
    334 #ifdef SYSVSHM
    335 	/* Initialize System V style shared memory. */
    336 	shminit();
    337 #endif
    338 
    339 #ifdef SYSVSEM
    340 	/* Initialize System V style semaphores. */
    341 	seminit();
    342 #endif
    343 
    344 #ifdef SYSVMSG
    345 	/* Initialize System V style message queues. */
    346 	msginit();
    347 #endif
    348 
    349 	/* Attach pseudo-devices. */
    350 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
    351 		(*pdev->pdev_attach)(pdev->pdev_count);
    352 
    353 	/*
    354 	 * Initialize protocols.  Block reception of incoming packets
    355 	 * until everything is ready.
    356 	 */
    357 	s = splnet();
    358 	ifinit();
    359 	domaininit();
    360 	splx(s);
    361 
    362 #ifdef GPROF
    363 	/* Initialize kernel profiling. */
    364 	kmstartup();
    365 #endif
    366 
    367 	/* Initialize system accouting. */
    368 	acct_init();
    369 
    370 	/*
    371 	 * Initialize signal-related data structures, and signal state
    372 	 * for proc0.
    373 	 */
    374 	signal_init();
    375 	p->p_sigacts = &sigacts0;
    376 	siginit(p);
    377 
    378 	/* Kick off timeout driven events by calling first time. */
    379 	schedcpu(NULL);
    380 
    381 	/*
    382 	 * Create process 1 (init(8)).  We do this now, as Unix has
    383 	 * historically had init be process 1, and changing this would
    384 	 * probably upset a lot of people.
    385 	 *
    386 	 * Note that process 1 won't immediately exec init(8), but will
    387 	 * wait for us to inform it that the root file system has been
    388 	 * mounted.
    389 	 */
    390 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
    391 		panic("fork init");
    392 
    393 	/*
    394 	 * Create any kernel threads who's creation was deferred because
    395 	 * initproc had not yet been created.
    396 	 */
    397 	kthread_run_deferred_queue();
    398 
    399 	/*
    400 	 * Now that device driver threads have been created, wait for
    401 	 * them to finish any deferred autoconfiguration.  Note we don't
    402 	 * need to lock this semaphore, since we haven't booted any
    403 	 * secondary processors, yet.
    404 	 */
    405 	while (config_pending)
    406 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
    407 
    408 	/*
    409 	 * Now that autoconfiguration has completed, we can determine
    410 	 * the root and dump devices.
    411 	 */
    412 	cpu_rootconf();
    413 	cpu_dumpconf();
    414 
    415 	/* Mount the root file system. */
    416 	do {
    417 		domountroothook();
    418 		if ((error = vfs_mountroot())) {
    419 			printf("cannot mount root, error = %d\n", error);
    420 			boothowto |= RB_ASKNAME;
    421 			setroot(root_device,
    422 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
    423 		}
    424 	} while (error != 0);
    425 	mountroothook_destroy();
    426 
    427 	mountlist.cqh_first->mnt_flag |= MNT_ROOTFS;
    428 	mountlist.cqh_first->mnt_op->vfs_refcount++;
    429 
    430 	/*
    431 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
    432 	 * reference it.
    433 	 */
    434 	if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
    435 		panic("cannot find root vnode");
    436 	cwdi0.cwdi_cdir = rootvnode;
    437 	VREF(cwdi0.cwdi_cdir);
    438 	VOP_UNLOCK(rootvnode, 0);
    439 	cwdi0.cwdi_rdir = NULL;
    440 
    441 	/*
    442 	 * Now that root is mounted, we can fixup initproc's CWD
    443 	 * info.  All other processes are kthreads, which merely
    444 	 * share proc0's CWD info.
    445 	 */
    446 	initproc->p_cwdi->cwdi_cdir = rootvnode;
    447 	VREF(initproc->p_cwdi->cwdi_cdir);
    448 	initproc->p_cwdi->cwdi_rdir = NULL;
    449 
    450 	/*
    451 	 * Now can look at time, having had a chance to verify the time
    452 	 * from the file system.  Reset p->p_rtime as it may have been
    453 	 * munched in mi_switch() after the time got set.
    454 	 */
    455 	proclist_lock_read();
    456 	s = splsched();
    457 	for (p = LIST_FIRST(&allproc); p != NULL;
    458 	     p = LIST_NEXT(p, p_list)) {
    459 		p->p_stats->p_start = mono_time = boottime = time;
    460 		if (p->p_cpu != NULL)
    461 			p->p_cpu->ci_schedstate.spc_runtime = time;
    462 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
    463 	}
    464 	splx(s);
    465 	proclist_unlock_read();
    466 
    467 	/* Create the pageout daemon kernel thread. */
    468 	uvm_swap_init();
    469 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
    470 		panic("fork pagedaemon");
    471 
    472 	/* Create the process reaper kernel thread. */
    473 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
    474 		panic("fork reaper");
    475 
    476 	/* Create the filesystem syncer kernel thread. */
    477 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
    478 		panic("fork syncer");
    479 
    480 	/* Create the aiodone daemon kernel thread. */
    481 	if (kthread_create1(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
    482 		panic("fork aiodoned");
    483 
    484 #if defined(MULTIPROCESSOR)
    485 	/* Boot the secondary processors. */
    486 	cpu_boot_secondary_processors();
    487 #endif
    488 
    489 	/* Initialize exec structures */
    490 	exec_init(1);
    491 
    492 	/*
    493 	 * Okay, now we can let init(8) exec!  It's off to userland!
    494 	 */
    495 	start_init_exec = 1;
    496 	wakeup((void *)&start_init_exec);
    497 
    498 #ifdef NVNODE_IMPLICIT
    499 	/*
    500 	 * If maximum number of vnodes in namei vnode cache is not explicitly
    501 	 * defined in kernel config, adjust the number such as we use roughly
    502 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
    503 	 */
    504 	usevnodes = (ptoa(physmem) / 200) / sizeof(struct vnode);
    505 	if (usevnodes > desiredvnodes)
    506 		desiredvnodes = usevnodes;
    507 #endif
    508 
    509 	/* The scheduler is an infinite loop. */
    510 	uvm_scheduler();
    511 	/* NOTREACHED */
    512 }
    513 
    514 static void
    515 check_console(struct proc *p)
    516 {
    517 	struct nameidata nd;
    518 	int error;
    519 
    520 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
    521 	error = namei(&nd);
    522 	if (error == 0)
    523 		vrele(nd.ni_vp);
    524 	else if (error == ENOENT)
    525 		printf("warning: no /dev/console\n");
    526 	else
    527 		printf("warning: lookup /dev/console: error %d\n", error);
    528 }
    529 
    530 /*
    531  * List of paths to try when searching for "init".
    532  */
    533 static const char *initpaths[] = {
    534 	"/sbin/init",
    535 	"/sbin/oinit",
    536 	"/sbin/init.bak",
    537 	NULL,
    538 };
    539 
    540 /*
    541  * Start the initial user process; try exec'ing each pathname in "initpaths".
    542  * The program is invoked with one argument containing the boot flags.
    543  */
    544 static void
    545 start_init(void *arg)
    546 {
    547 	struct proc *p = arg;
    548 	vaddr_t addr;
    549 	struct sys_execve_args /* {
    550 		syscallarg(const char *) path;
    551 		syscallarg(char * const *) argp;
    552 		syscallarg(char * const *) envp;
    553 	} */ args;
    554 	int options, i, error;
    555 	register_t retval[2];
    556 	char flags[4], *flagsp;
    557 	const char **pathp, *path, *slash;
    558 	char *ucp, **uap, *arg0, *arg1 = NULL;
    559 
    560 	/*
    561 	 * Now in process 1.
    562 	 */
    563 	strncpy(p->p_comm, "init", MAXCOMLEN);
    564 
    565 	/*
    566 	 * Wait for main() to tell us that it's safe to exec.
    567 	 */
    568 	while (start_init_exec == 0)
    569 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
    570 
    571 	/*
    572 	 * This is not the right way to do this.  We really should
    573 	 * hand-craft a descriptor onto /dev/console to hand to init,
    574 	 * but that's a _lot_ more work, and the benefit from this easy
    575 	 * hack makes up for the "good is the enemy of the best" effect.
    576 	 */
    577 	check_console(p);
    578 
    579 	/*
    580 	 * Need just enough stack to hold the faked-up "execve()" arguments.
    581 	 */
    582 	addr = USRSTACK - PAGE_SIZE;
    583 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
    584                     NULL, UVM_UNKNOWN_OFFSET, 0,
    585                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
    586 		    UVM_ADV_NORMAL,
    587                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
    588 		panic("init: couldn't allocate argument space");
    589 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
    590 
    591 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
    592 		ucp = (char *)(addr + PAGE_SIZE);
    593 
    594 		/*
    595 		 * Construct the boot flag argument.
    596 		 */
    597 		flagsp = flags;
    598 		*flagsp++ = '-';
    599 		options = 0;
    600 
    601 		if (boothowto & RB_SINGLE) {
    602 			*flagsp++ = 's';
    603 			options = 1;
    604 		}
    605 #ifdef notyet
    606 		if (boothowto & RB_FASTBOOT) {
    607 			*flagsp++ = 'f';
    608 			options = 1;
    609 		}
    610 #endif
    611 
    612 		/*
    613 		 * Move out the flags (arg 1), if necessary.
    614 		 */
    615 		if (options != 0) {
    616 			*flagsp++ = '\0';
    617 			i = flagsp - flags;
    618 #ifdef DEBUG
    619 			printf("init: copying out flags `%s' %d\n", flags, i);
    620 #endif
    621 			(void)copyout((caddr_t)flags, (caddr_t)(ucp -= i), i);
    622 			arg1 = ucp;
    623 		}
    624 
    625 		/*
    626 		 * Move out the file name (also arg 0).
    627 		 */
    628 		i = strlen(path) + 1;
    629 #ifdef DEBUG
    630 		printf("init: copying out path `%s' %d\n", path, i);
    631 #endif
    632 		(void)copyout((caddr_t)path, (caddr_t)(ucp -= i), i);
    633 		arg0 = ucp;
    634 
    635 		/*
    636 		 * Move out the arg pointers.
    637 		 */
    638 		uap = (char **)((long)ucp & ~ALIGNBYTES);
    639 		(void)suword((caddr_t)--uap, 0);	/* terminator */
    640 		if (options != 0)
    641 			(void)suword((caddr_t)--uap, (long)arg1);
    642 		slash = strrchr(path, '/');
    643 		if (slash)
    644 			(void)suword((caddr_t)--uap,
    645 			    (long)arg0 + (slash + 1 - path));
    646 		else
    647 			(void)suword((caddr_t)--uap, (long)arg0);
    648 
    649 		/*
    650 		 * Point at the arguments.
    651 		 */
    652 		SCARG(&args, path) = arg0;
    653 		SCARG(&args, argp) = uap;
    654 		SCARG(&args, envp) = NULL;
    655 
    656 		/*
    657 		 * Now try to exec the program.  If can't for any reason
    658 		 * other than it doesn't exist, complain.
    659 		 */
    660 		error = sys_execve(p, &args, retval);
    661 		if (error == 0 || error == EJUSTRETURN) {
    662 			KERNEL_PROC_UNLOCK(p);
    663 			return;
    664 		}
    665 		if (error != ENOENT)
    666 			printf("exec %s: error %d\n", path, error);
    667 	}
    668 	printf("init: not found\n");
    669 	panic("no init");
    670 }
    671