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init_main.c revision 1.211
      1 /*	$NetBSD: init_main.c,v 1.211 2002/11/17 22:53:46 chs 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 1.211 2002/11/17 22:53:46 chs 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 
     56 #include "rnd.h"
     57 
     58 #include <sys/param.h>
     59 #include <sys/acct.h>
     60 #include <sys/filedesc.h>
     61 #include <sys/file.h>
     62 #include <sys/errno.h>
     63 #include <sys/callout.h>
     64 #include <sys/kernel.h>
     65 #include <sys/mount.h>
     66 #include <sys/proc.h>
     67 #include <sys/kthread.h>
     68 #include <sys/resourcevar.h>
     69 #include <sys/signalvar.h>
     70 #include <sys/systm.h>
     71 #include <sys/vnode.h>
     72 #include <sys/tty.h>
     73 #include <sys/conf.h>
     74 #include <sys/disklabel.h>
     75 #include <sys/buf.h>
     76 #include <sys/device.h>
     77 #include <sys/disk.h>
     78 #include <sys/exec.h>
     79 #include <sys/socketvar.h>
     80 #include <sys/protosw.h>
     81 #include <sys/reboot.h>
     82 #include <sys/user.h>
     83 #include <sys/sysctl.h>
     84 #include <sys/event.h>
     85 #ifdef SYSVSHM
     86 #include <sys/shm.h>
     87 #endif
     88 #ifdef SYSVSEM
     89 #include <sys/sem.h>
     90 #endif
     91 #ifdef SYSVMSG
     92 #include <sys/msg.h>
     93 #endif
     94 #ifdef SYSTRACE
     95 #include <sys/systrace.h>
     96 #endif
     97 #include <sys/domain.h>
     98 #include <sys/mbuf.h>
     99 #include <sys/namei.h>
    100 #if NRND > 0
    101 #include <sys/rnd.h>
    102 #endif
    103 #ifndef PIPE_SOCKETPAIR
    104 #include <sys/pipe.h>
    105 #endif
    106 #ifdef LKM
    107 #include <sys/lkm.h>
    108 #endif
    109 
    110 #include <sys/syscall.h>
    111 #include <sys/syscallargs.h>
    112 
    113 #include <ufs/ufs/quota.h>
    114 
    115 #include <miscfs/genfs/genfs.h>
    116 #include <miscfs/syncfs/syncfs.h>
    117 
    118 #include <machine/cpu.h>
    119 
    120 #include <uvm/uvm.h>
    121 
    122 #include <dev/cons.h>
    123 
    124 #include <net/if.h>
    125 #include <net/raw_cb.h>
    126 
    127 const char copyright[] =
    128 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002\n"
    129 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
    130 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
    131 "    The Regents of the University of California.  All rights reserved.\n"
    132 "\n";
    133 
    134 /* Components of the first process -- never freed. */
    135 struct	session session0;
    136 struct	pgrp pgrp0;
    137 struct	proc proc0;
    138 struct	pcred cred0;
    139 struct	filedesc0 filedesc0;
    140 struct	cwdinfo cwdi0;
    141 struct	plimit limit0;
    142 struct	vmspace vmspace0;
    143 struct	sigacts sigacts0;
    144 #ifndef curproc
    145 struct	proc *curproc = &proc0;
    146 #endif
    147 struct	proc *initproc;
    148 
    149 int	cmask = CMASK;
    150 extern	struct user *proc0paddr;
    151 
    152 struct	vnode *rootvp, *swapdev_vp;
    153 int	boothowto;
    154 int	cold = 1;			/* still working on startup */
    155 struct	timeval boottime;
    156 
    157 __volatile int start_init_exec;		/* semaphore for start_init() */
    158 
    159 static void check_console(struct proc *p);
    160 static void start_init(void *);
    161 void main(void);
    162 
    163 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
    164 
    165 /*
    166  * System startup; initialize the world, create process 0, mount root
    167  * filesystem, and fork to create init and pagedaemon.  Most of the
    168  * hard work is done in the lower-level initialization routines including
    169  * startup(), which does memory initialization and autoconfiguration.
    170  */
    171 void
    172 main(void)
    173 {
    174 	struct proc *p;
    175 	struct pdevinit *pdev;
    176 	int s, error;
    177 	u_int i;
    178 	rlim_t lim;
    179 	extern struct pdevinit pdevinit[];
    180 	extern void schedcpu(void *);
    181 #if defined(NFSSERVER) || defined(NFS)
    182 	extern void nfs_init(void);
    183 #endif
    184 #ifdef NVNODE_IMPLICIT
    185 	int usevnodes;
    186 #endif
    187 
    188 	/*
    189 	 * Initialize the current process pointer (curproc) before
    190 	 * any possible traps/probes to simplify trap processing.
    191 	 */
    192 	simple_lock_init(&proc0.p_raslock);
    193 	p = &proc0;
    194 	curproc = p;
    195 	p->p_cpu = curcpu();
    196 	/*
    197 	 * Attempt to find console and initialize
    198 	 * in case of early panic or other messages.
    199 	 */
    200 	consinit();
    201 	printf("%s", copyright);
    202 
    203 	KERNEL_LOCK_INIT();
    204 
    205 	uvm_init();
    206 
    207 	/* Do machine-dependent initialization. */
    208 	cpu_startup();
    209 
    210 	/* Initialize callouts. */
    211 	callout_startup();
    212 
    213 	/*
    214 	 * Initialize mbuf's.  Do this now because we might attempt to
    215 	 * allocate mbufs or mbuf clusters during autoconfiguration.
    216 	 */
    217 	mbinit();
    218 
    219 	/* Initialize kqueues. */
    220 	kqueue_init();
    221 
    222 	/* Initialize sockets. */
    223 	soinit();
    224 
    225 	/*
    226 	 * The following 3 things must be done before autoconfiguration.
    227 	 */
    228 	disk_init();		/* initialize disk list */
    229 	tty_init();		/* initialize tty list */
    230 #if NRND > 0
    231 	rnd_init();		/* initialize RNG */
    232 #endif
    233 
    234 	/* Initialize the sysctl subsystem. */
    235 	sysctl_init();
    236 
    237 	/*
    238 	 * Initialize process and pgrp structures.
    239 	 */
    240 	procinit();
    241 
    242 #ifdef LKM
    243 	/* Initialize the LKM system. */
    244 	lkm_init();
    245 #endif
    246 
    247 	/*
    248 	 * Create process 0 (the swapper).
    249 	 */
    250 	s = proclist_lock_write();
    251 	LIST_INSERT_HEAD(&allproc, p, p_list);
    252 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
    253 	proclist_unlock_write(s);
    254 
    255 	p->p_pgrp = &pgrp0;
    256 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
    257 	LIST_INIT(&pgrp0.pg_members);
    258 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
    259 
    260 	pgrp0.pg_session = &session0;
    261 	session0.s_count = 1;
    262 	session0.s_sid = p->p_pid;
    263 	session0.s_leader = p;
    264 
    265 	/*
    266 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
    267 	 * init(8) when they exit.  init(8) can easily wait them out
    268 	 * for us.
    269 	 */
    270 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
    271 	p->p_stat = SONPROC;
    272 	p->p_nice = NZERO;
    273 	p->p_emul = &emul_netbsd;
    274 #ifdef __HAVE_SYSCALL_INTERN
    275 	(*p->p_emul->e_syscall_intern)(p);
    276 #endif
    277 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
    278 
    279 	callout_init(&p->p_realit_ch);
    280 	callout_init(&p->p_tsleep_ch);
    281 
    282 	/* Create credentials. */
    283 	cred0.p_refcnt = 1;
    284 	p->p_cred = &cred0;
    285 	p->p_ucred = crget();
    286 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
    287 
    288 	/* Create the file descriptor table. */
    289 	finit();
    290 	p->p_fd = &filedesc0.fd_fd;
    291 	fdinit1(&filedesc0);
    292 
    293 	/* Create the CWD info. */
    294 	p->p_cwdi = &cwdi0;
    295 	cwdi0.cwdi_cmask = cmask;
    296 	cwdi0.cwdi_refcnt = 1;
    297 
    298 	/* Create the limits structures. */
    299 	p->p_limit = &limit0;
    300 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
    301 		limit0.pl_rlimit[i].rlim_cur =
    302 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
    303 
    304 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
    305 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
    306 	    maxfiles < NOFILE ? maxfiles : NOFILE;
    307 
    308 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
    309 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
    310 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
    311 
    312 	lim = ptoa(uvmexp.free);
    313 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
    314 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
    315 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
    316 	limit0.pl_corename = defcorename;
    317 	limit0.p_refcnt = 1;
    318 
    319 	/*
    320 	 * Initialize proc0's vmspace, which uses the kernel pmap.
    321 	 * All kernel processes (which never have user space mappings)
    322 	 * share proc0's vmspace, and thus, the kernel pmap.
    323 	 */
    324 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
    325 	    trunc_page(VM_MAX_ADDRESS));
    326 	p->p_vmspace = &vmspace0;
    327 
    328 	p->p_addr = proc0paddr;				/* XXX */
    329 
    330 	/*
    331 	 * We continue to place resource usage info in the
    332 	 * user struct so they're pageable.
    333 	 */
    334 	p->p_stats = &p->p_addr->u_stats;
    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(p);
    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 	/* Attach pseudo-devices. */
    386 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
    387 		(*pdev->pdev_attach)(pdev->pdev_count);
    388 
    389 	/*
    390 	 * Initialize protocols.  Block reception of incoming packets
    391 	 * until everything is ready.
    392 	 */
    393 	s = splnet();
    394 	ifinit();
    395 	domaininit();
    396 	if_attachdomain();
    397 	splx(s);
    398 
    399 #ifdef GPROF
    400 	/* Initialize kernel profiling. */
    401 	kmstartup();
    402 #endif
    403 
    404 	/* Initialize system accouting. */
    405 	acct_init();
    406 
    407 #ifdef SYSTRACE
    408 	systrace_init();
    409 #endif
    410 	/*
    411 	 * Initialize signal-related data structures, and signal state
    412 	 * for proc0.
    413 	 */
    414 	signal_init();
    415 	p->p_sigacts = &sigacts0;
    416 	siginit(p);
    417 
    418 	/* Kick off timeout driven events by calling first time. */
    419 	schedcpu(NULL);
    420 
    421 	/*
    422 	 * Create process 1 (init(8)).  We do this now, as Unix has
    423 	 * historically had init be process 1, and changing this would
    424 	 * probably upset a lot of people.
    425 	 *
    426 	 * Note that process 1 won't immediately exec init(8), but will
    427 	 * wait for us to inform it that the root file system has been
    428 	 * mounted.
    429 	 */
    430 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
    431 		panic("fork init");
    432 
    433 	/*
    434 	 * Create any kernel threads who's creation was deferred because
    435 	 * initproc had not yet been created.
    436 	 */
    437 	kthread_run_deferred_queue();
    438 
    439 	/*
    440 	 * Now that device driver threads have been created, wait for
    441 	 * them to finish any deferred autoconfiguration.  Note we don't
    442 	 * need to lock this semaphore, since we haven't booted any
    443 	 * secondary processors, yet.
    444 	 */
    445 	while (config_pending)
    446 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
    447 
    448 	/*
    449 	 * Finalize configuration now that all real devices have been
    450 	 * found.  This needs to be done before the root device is
    451 	 * selected, since finalization may create the root device.
    452 	 */
    453 	config_finalize();
    454 
    455 	/*
    456 	 * Now that autoconfiguration has completed, we can determine
    457 	 * the root and dump devices.
    458 	 */
    459 	cpu_rootconf();
    460 	cpu_dumpconf();
    461 
    462 	/* Mount the root file system. */
    463 	do {
    464 		domountroothook();
    465 		if ((error = vfs_mountroot())) {
    466 			printf("cannot mount root, error = %d\n", error);
    467 			boothowto |= RB_ASKNAME;
    468 			setroot(root_device,
    469 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
    470 		}
    471 	} while (error != 0);
    472 	mountroothook_destroy();
    473 
    474 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
    475 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
    476 
    477 	/*
    478 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
    479 	 * reference it.
    480 	 */
    481 	if (VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode))
    482 		panic("cannot find root vnode");
    483 	cwdi0.cwdi_cdir = rootvnode;
    484 	VREF(cwdi0.cwdi_cdir);
    485 	VOP_UNLOCK(rootvnode, 0);
    486 	cwdi0.cwdi_rdir = NULL;
    487 
    488 	/*
    489 	 * Now that root is mounted, we can fixup initproc's CWD
    490 	 * info.  All other processes are kthreads, which merely
    491 	 * share proc0's CWD info.
    492 	 */
    493 	initproc->p_cwdi->cwdi_cdir = rootvnode;
    494 	VREF(initproc->p_cwdi->cwdi_cdir);
    495 	initproc->p_cwdi->cwdi_rdir = NULL;
    496 
    497 	/*
    498 	 * Now can look at time, having had a chance to verify the time
    499 	 * from the file system.  Reset p->p_rtime as it may have been
    500 	 * munched in mi_switch() after the time got set.
    501 	 */
    502 	proclist_lock_read();
    503 	s = splsched();
    504 	for (p = LIST_FIRST(&allproc); p != NULL;
    505 	     p = LIST_NEXT(p, p_list)) {
    506 		p->p_stats->p_start = mono_time = boottime = time;
    507 		if (p->p_cpu != NULL)
    508 			p->p_cpu->ci_schedstate.spc_runtime = time;
    509 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
    510 	}
    511 	splx(s);
    512 	proclist_unlock_read();
    513 
    514 	/* Create the pageout daemon kernel thread. */
    515 	uvm_swap_init();
    516 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
    517 		panic("fork pagedaemon");
    518 
    519 	/* Create the process reaper kernel thread. */
    520 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
    521 		panic("fork reaper");
    522 
    523 	/* Create the filesystem syncer kernel thread. */
    524 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
    525 		panic("fork syncer");
    526 
    527 	/* Create the aiodone daemon kernel thread. */
    528 	if (kthread_create1(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
    529 		panic("fork aiodoned");
    530 
    531 #if defined(MULTIPROCESSOR)
    532 	/* Boot the secondary processors. */
    533 	cpu_boot_secondary_processors();
    534 #endif
    535 
    536 	/* Initialize exec structures */
    537 	exec_init(1);
    538 
    539 #ifndef PIPE_SOCKETPAIR
    540 	/* Initialize pipe structures */
    541 	pipe_init();
    542 #endif
    543 
    544 	/*
    545 	 * Okay, now we can let init(8) exec!  It's off to userland!
    546 	 */
    547 	start_init_exec = 1;
    548 	wakeup((void *)&start_init_exec);
    549 
    550 	/* The scheduler is an infinite loop. */
    551 	uvm_scheduler();
    552 	/* NOTREACHED */
    553 }
    554 
    555 static void
    556 check_console(struct proc *p)
    557 {
    558 	struct nameidata nd;
    559 	int error;
    560 
    561 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
    562 	error = namei(&nd);
    563 	if (error == 0)
    564 		vrele(nd.ni_vp);
    565 	else if (error == ENOENT)
    566 		printf("warning: no /dev/console\n");
    567 	else
    568 		printf("warning: lookup /dev/console: error %d\n", error);
    569 }
    570 
    571 /*
    572  * List of paths to try when searching for "init".
    573  */
    574 static const char *initpaths[] = {
    575 	"/sbin/init",
    576 	"/sbin/oinit",
    577 	"/sbin/init.bak",
    578 	NULL,
    579 };
    580 
    581 /*
    582  * Start the initial user process; try exec'ing each pathname in "initpaths".
    583  * The program is invoked with one argument containing the boot flags.
    584  */
    585 static void
    586 start_init(void *arg)
    587 {
    588 	struct proc *p = arg;
    589 	vaddr_t addr;
    590 	struct sys_execve_args /* {
    591 		syscallarg(const char *) path;
    592 		syscallarg(char * const *) argp;
    593 		syscallarg(char * const *) envp;
    594 	} */ args;
    595 	int options, i, error;
    596 	register_t retval[2];
    597 	char flags[4], *flagsp;
    598 	const char *path, *slash;
    599 	char *ucp, **uap, *arg0, *arg1 = NULL;
    600 	char ipath[129];
    601 	int ipx, len;
    602 
    603 	/*
    604 	 * Now in process 1.
    605 	 */
    606 	strncpy(p->p_comm, "init", MAXCOMLEN);
    607 
    608 	/*
    609 	 * Wait for main() to tell us that it's safe to exec.
    610 	 */
    611 	while (start_init_exec == 0)
    612 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
    613 
    614 	/*
    615 	 * This is not the right way to do this.  We really should
    616 	 * hand-craft a descriptor onto /dev/console to hand to init,
    617 	 * but that's a _lot_ more work, and the benefit from this easy
    618 	 * hack makes up for the "good is the enemy of the best" effect.
    619 	 */
    620 	check_console(p);
    621 
    622 	/*
    623 	 * Need just enough stack to hold the faked-up "execve()" arguments.
    624 	 */
    625 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
    626 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
    627                     NULL, UVM_UNKNOWN_OFFSET, 0,
    628                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
    629 		    UVM_ADV_NORMAL,
    630                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
    631 		panic("init: couldn't allocate argument space");
    632 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
    633 
    634 	ipx = 0;
    635 	while (1) {
    636 		if (boothowto & RB_ASKNAME) {
    637 			printf("init path");
    638 			if (initpaths[ipx])
    639 				printf(" (default %s)", initpaths[ipx]);
    640 			printf(": ");
    641 			len = cngetsn(ipath, sizeof(ipath)-1);
    642 			if (len == 0) {
    643 				if (initpaths[ipx])
    644 					path = initpaths[ipx++];
    645 				else
    646 					continue;
    647 			} else {
    648 				ipath[len] = '\0';
    649 				path = ipath;
    650 			}
    651 		} else {
    652 			if ((path = initpaths[ipx++]) == NULL)
    653 				break;
    654 		}
    655 
    656 		ucp = (char *)USRSTACK;
    657 
    658 		/*
    659 		 * Construct the boot flag argument.
    660 		 */
    661 		flagsp = flags;
    662 		*flagsp++ = '-';
    663 		options = 0;
    664 
    665 		if (boothowto & RB_SINGLE) {
    666 			*flagsp++ = 's';
    667 			options = 1;
    668 		}
    669 #ifdef notyet
    670 		if (boothowto & RB_FASTBOOT) {
    671 			*flagsp++ = 'f';
    672 			options = 1;
    673 		}
    674 #endif
    675 
    676 		/*
    677 		 * Move out the flags (arg 1), if necessary.
    678 		 */
    679 		if (options != 0) {
    680 			*flagsp++ = '\0';
    681 			i = flagsp - flags;
    682 #ifdef DEBUG
    683 			printf("init: copying out flags `%s' %d\n", flags, i);
    684 #endif
    685 			arg1 = STACK_ALLOC(ucp, i);
    686 			ucp = STACK_MAX(arg1, i);
    687 			(void)copyout((caddr_t)flags, arg1, i);
    688 		}
    689 
    690 		/*
    691 		 * Move out the file name (also arg 0).
    692 		 */
    693 		i = strlen(path) + 1;
    694 #ifdef DEBUG
    695 		printf("init: copying out path `%s' %d\n", path, i);
    696 #else
    697 		if (boothowto & RB_ASKNAME || path != initpaths[0])
    698 			printf("init: trying %s\n", path);
    699 #endif
    700 		arg0 = STACK_ALLOC(ucp, i);
    701 		ucp = STACK_MAX(arg0, i);
    702 		(void)copyout((caddr_t)path, arg0, i);
    703 
    704 		/*
    705 		 * Move out the arg pointers.
    706 		 */
    707 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
    708 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
    709 		SCARG(&args, path) = arg0;
    710 		SCARG(&args, argp) = uap;
    711 		SCARG(&args, envp) = NULL;
    712 		slash = strrchr(path, '/');
    713 		if (slash)
    714 			(void)suword((caddr_t)uap++,
    715 			    (long)arg0 + (slash + 1 - path));
    716 		else
    717 			(void)suword((caddr_t)uap++, (long)arg0);
    718 		if (options != 0)
    719 			(void)suword((caddr_t)uap++, (long)arg1);
    720 		(void)suword((caddr_t)uap++, 0);	/* terminator */
    721 
    722 		/*
    723 		 * Now try to exec the program.  If can't for any reason
    724 		 * other than it doesn't exist, complain.
    725 		 */
    726 		error = sys_execve(p, &args, retval);
    727 		if (error == 0 || error == EJUSTRETURN) {
    728 			KERNEL_PROC_UNLOCK(p);
    729 			return;
    730 		}
    731 		printf("exec %s: error %d\n", path, error);
    732 	}
    733 	printf("init: not found\n");
    734 	panic("no init");
    735 }
    736