#include "../h/param.h"#include "../h/systm.h"#include "../h/dir.h"#include "../h/user.h"#include "../h/filsys.h"#include "../h/mount.h"#include "../h/map.h"#include "../h/proc.h"#include "../h/inode.h"#include "../h/seg.h"#include "../h/conf.h"#include "../h/buf.h"/* * Initialization code. * Called from cold start routine as * soon as a stack and segmentation * have been established. * Functions: *	clear and free user core *	turn on clock *	hand craft 0th process *	call all initialization routines *	fork - process 0 to schedule *	     - process 1 execute bootstrap * * loop at low address in user mode -- /etc/init *	cannot be executed. */main(){	startup();	/*	 * set up system process	 */	proc[0].p_addr = ka6->r[0];	proc[0].p_size = USIZE;	proc[0].p_stat = SRUN;	proc[0].p_flag |= SLOAD|SSYS;	proc[0].p_nice = NZERO;	u.u_procp = &proc[0];	u.u_cmask = CMASK;	/*	 * Initialize devices and	 * set up 'known' i-nodes	 */	clkstart();	cinit();	binit();	iinit();	rootdir = iget(rootdev, (ino_t)ROOTINO);	rootdir->i_flag &= ~ILOCK;	u.u_cdir = iget(rootdev, (ino_t)ROOTINO);	u.u_cdir->i_flag &= ~ILOCK;	u.u_rdir = NULL;	/*	 * make init process	 * enter scheduling loop	 * with system process	 */	if(newproc()) {		expand(USIZE + (int)btoc(szicode));		estabur((unsigned)0, btoc(szicode), (unsigned)0, 0, RO);		copyout((caddr_t)icode, (caddr_t)0, szicode);		/*		 * Return goes to loc. 0 of user init		 * code just copied out.		 */		return;	}	sched();}/* * iinit is called once (from main) * very early in initialization. * It reads the root's super block * and initializes the current date * from the last modified date. * * panic: iinit -- cannot read the super * block. Usually because of an IO error. */iinit(){	register struct buf *cp, *bp;	register struct filsys *fp;	(*bdevsw[major(rootdev)].d_open)(rootdev, 1);	bp = bread(rootdev, SUPERB);	cp = geteblk();	if(u.u_error)		panic("iinit");	bcopy(bp->b_un.b_addr, cp->b_un.b_addr, sizeof(struct filsys));	brelse(bp);	mount[0].m_bufp = cp;	mount[0].m_dev = rootdev;	fp = cp->b_un.b_filsys;	fp->s_flock = 0;	fp->s_ilock = 0;	fp->s_ronly = 0;	time = fp->s_time;}/* * This is the set of buffers proper, whose heads * were declared in buf.h.  There can exist buffer * headers not pointing here that are used purely * as arguments to the I/O routines to describe * I/O to be done-- e.g. swbuf for * swapping. */char	buffers[NBUF][BSIZE+BSLOP];/* * Initialize the buffer I/O system by freeing * all buffers and setting all device buffer lists to empty. */binit(){	register struct buf *bp;	register struct buf *dp;	register int i;	struct bdevsw *bdp;	bfreelist.b_forw = bfreelist.b_back =	    bfreelist.av_forw = bfreelist.av_back = &bfreelist;	for (i=0; i<NBUF; i++) {		bp = &buf[i];		bp->b_dev = NODEV;		bp->b_un.b_addr = buffers[i];		bp->b_back = &bfreelist;		bp->b_forw = bfreelist.b_forw;		bfreelist.b_forw->b_back = bp;		bfreelist.b_forw = bp;		bp->b_flags = B_BUSY;		brelse(bp);	}	for (bdp = bdevsw; bdp->d_open; bdp++) {		dp = bdp->d_tab;		if(dp) {			dp->b_forw = dp;			dp->b_back = dp;		}		nblkdev++;	}}