restor.c

unix v7是最后一个广泛发布的研究型UNIX版本

	for (i = 0; i < sizeof(ino_t); i++)
		writec(*cp++);
	for (i = 0; i < DIRSIZ; i++) {
		writec(*cp);
		if (*cp++ == 0)
			return;
	}
	return;
}

getent(bf)
register char *bf;
{
	register i;

	for (i = 0; i < sizeof(ino_t); i++)
		*bf++ = readc();
	for (i = 0; i < DIRSIZ; i++)
		if ((*bf++ = readc()) == 0)
			return;
	return;
}

/*
 * read/write te directory file
 */
writec(c)
char c;
{
	drblock[bpt++] = c;
	seekpt++;
	if (bpt >= BSIZE) {
		bpt = 0;
		write(df, drblock, BSIZE);
	}
}

readc()
{
	if (bpt >= BSIZE) {
		read(df, drblock, BSIZE);
		bpt = 0;
	}
	return(drblock[bpt++]);
}

mseek(pt)
daddr_t pt;
{
	bpt = BSIZE;
	lseek(df, pt, 0);
}

flsh()
{
	write(df, drblock, bpt+1);
}

/*
 * search the directory inode ino
 * looking for entry cp
 */
ino_t
search(inum, cp)
ino_t	inum;
char	*cp;
{
	register i;
	struct direct dir;

	for (i = 0; i < MAXINO; i++)
		if (inotab[i].t_ino == inum) {
			goto found;
		}
	return(0);
found:
	mseek(inotab[i].t_seekpt);
	do {
		getent((char *)&dir);
		if (direq(dir.d_name, "/"))
			return(0);
	} while (direq(dir.d_name, cp) == 0);
	return(dir.d_ino);
}

/*
 * Search the directory tree rooted at inode 2
 * for the path pointed at by n
 */
psearch(n)
char	*n;
{
	register char *cp, *cp1;
	char c;

	ino = 2;
	if (*(cp = n) == '/')
		cp++;
next:
	cp1 = cp + 1;
	while (*cp1 != '/' && *cp1)
		cp1++;
	c = *cp1;
	*cp1 = 0;
	ino = search(ino, cp);
	if (ino == 0) {
		*cp1 = c;
		return(0);
	}
	*cp1 = c;
	if (c == '/') {
		cp = cp1+1;
		goto next;
	}
	return(ino);
}

direq(s1, s2)
register char *s1, *s2;
{
	register i;

	for (i = 0; i < DIRSIZ; i++)
		if (*s1++ == *s2) {
			if (*s2++ == 0)
				return(1);
		} else
			return(0);
	return(1);
}
#endif

/*
 * read/write a disk block, be sure to update the buffer
 * cache if needed.
 */
dwrite(bno, b)
daddr_t	bno;
char	*b;
{
	register i;

	for (i = 0; i < NCACHE; i++) {
		if (cache[i].c_bno == bno) {
			copy(b, cache[i].c_block, BSIZE);
			cache[i].c_time = 0;
			break;
		}
		else
			cache[i].c_time++;
	}
	lseek(fi, bno*BSIZE, 0);
	if(write(fi, b, BSIZE) != BSIZE) {
#ifdef STANDALONE
		printf("disk write error %D\n", bno);
#else
		fprintf(stderr, "disk write error %ld\n", bno);
#endif
		exit(1);
	}
}

dread(bno, buf, cnt)
daddr_t bno;
char *buf;
{
	register i, j;

	j = 0;
	for (i = 0; i < NCACHE; i++) {
		if (++curcache >= NCACHE)
			curcache = 0;
		if (cache[curcache].c_bno == bno) {
			copy(cache[curcache].c_block, buf, cnt);
			cache[curcache].c_time = 0;
			return;
		}
		else {
			cache[curcache].c_time++;
			if (cache[j].c_time < cache[curcache].c_time)
				j = curcache;
		}
	}

	lseek(fi, bno*BSIZE, 0);
	if (read(fi, cache[j].c_block, BSIZE) != BSIZE) {
#ifdef STANDALONE
		printf("read error %D\n", bno);
#else
		printf("read error %ld\n", bno);
#endif
		exit(1);
	}
	copy(cache[j].c_block, buf, cnt);
	cache[j].c_time = 0;
	cache[j].c_bno = bno;
}

/*
 * the inode manpulation routines. Like the system.
 *
 * clri zeros the inode
 */
clri(ip)
struct dinode *ip;
{
	int i, *p;
	i = sizeof(struct dinode)/sizeof(int);
	p = (int *)ip;
	do
		*p++ = 0;
	while(--i);
}

/*
 * itrunc/tloop/bfree free all of the blocks pointed at by the inode
 */
itrunc(ip)
register struct dinode *ip;
{
	register i;
	daddr_t bn, iaddr[NADDR];

	if (ip->di_mode == 0)
		return;
	i = ip->di_mode & IFMT;
	if (i != IFDIR && i != IFREG)
		return;
	l3tol(iaddr, ip->di_addr, NADDR);
	for(i=NADDR-1;i>=0;i--) {
		bn = iaddr[i];
		if(bn == 0) continue;
		switch(i) {

		default:
			bfree(bn);
			break;

		case NADDR-3:
			tloop(bn, 0, 0);
			break;

		case NADDR-2:
			tloop(bn, 1, 0);
			break;

		case NADDR-1:
			tloop(bn, 1, 1);
		}
	}
	ip->di_size = 0;
}

tloop(bn, f1, f2)
daddr_t	bn;
int	f1, f2;
{
	register i;
	daddr_t nb;
	union {
		char	data[BSIZE];
		daddr_t	indir[NINDIR];
	} ibuf;

	dread(bn, ibuf.data, BSIZE);
	for(i=NINDIR-1;i>=0;i--) {
		nb = ibuf.indir[i];
		if(nb) {
			if(f1)
				tloop(nb, f2, 0);
			else
				bfree(nb);
		}
	}
	bfree(bn);
}

bfree(bn)
daddr_t	bn;
{
	register i;
	union {
		char	data[BSIZE];
		struct	fblk frees;
	} fbuf;

	if(sblock.s_nfree >= NICFREE) {
		fbuf.df_nfree = sblock.s_nfree;
		for(i=0;i<NICFREE;i++)
			fbuf.df_free[i] = sblock.s_free[i];
		sblock.s_nfree = 0;
		dwrite(bn, fbuf.data);
	}
	sblock.s_free[sblock.s_nfree++] = bn;
}

/*
 * allocate a block off the free list.
 */
daddr_t
balloc()
{
	daddr_t	bno;
	register i;
	static char zeroes[BSIZE];
	union {
		char	data[BSIZE];
		struct	fblk frees;
	} fbuf;

	if(sblock.s_nfree == 0 || (bno=sblock.s_free[--sblock.s_nfree]) == 0) {
#ifdef STANDALONE
		printf("Out of space\n");
#else
		fprintf(stderr, "Out of space.\n");
#endif
		exit(1);
	}
	if(sblock.s_nfree == 0) {
		dread(bno, fbuf.data, BSIZE);
		sblock.s_nfree = fbuf.df_nfree;
		for(i=0;i<NICFREE;i++)
			sblock.s_free[i] = fbuf.df_free[i];
	}
	dwrite(bno, zeroes);
	return(bno);
}

/*
 * map a block number into a block address, ensuring
 * all of the correct indirect blocks are around. Allocate
 * the block requested.
 */
daddr_t
bmap(iaddr, bn)
daddr_t	iaddr[NADDR];
daddr_t	bn;
{
	register i;
	int j, sh;
	daddr_t nb, nnb;
	daddr_t indir[NINDIR];

	/*
	 * blocks 0..NADDR-4 are direct blocks
	 */
	if(bn < NADDR-3) {
		iaddr[bn] = nb = balloc();
		return(nb);
	}

	/*
	 * addresses NADDR-3, NADDR-2, and NADDR-1
	 * have single, double, triple indirect blocks.
	 * the first step is to determine
	 * how many levels of indirection.
	 */
	sh = 0;
	nb = 1;
	bn -= NADDR-3;
	for(j=3; j>0; j--) {
		sh += NSHIFT;
		nb <<= NSHIFT;
		if(bn < nb)
			break;
		bn -= nb;
	}
	if(j == 0) {
		return((daddr_t)0);
	}

	/*
	 * fetch the address from the inode
	 */
	if((nb = iaddr[NADDR-j]) == 0) {
		iaddr[NADDR-j] = nb = balloc();
	}

	/*
	 * fetch through the indirect blocks
	 */
	for(; j<=3; j++) {
		dread(nb, (char *)indir, BSIZE);
		sh -= NSHIFT;
		i = (bn>>sh) & NMASK;
		nnb = indir[i];
		if(nnb == 0) {
			nnb = balloc();
			indir[i] = nnb;
			dwrite(nb, (char *)indir);
		}
		nb = nnb;
	}
	return(nb);
}

/*
 * read the tape into buf, then return whether or
 * or not it is a header block.
 */
gethead(buf)
struct spcl *buf;
{
	readtape((char *)buf);
	if (buf->c_magic != MAGIC || checksum((int *) buf) == 0)
		return(0);
	return(1);
}

/*
 * return whether or not the buffer contains a header block
 */
ishead(buf)
struct spcl *buf;
{
	if (buf->c_magic != MAGIC || checksum((int *) buf) == 0)
		return(0);
	return(1);
}

checktype(b, t)
struct	spcl *b;
int	t;
{
	return(b->c_type == t);
}


checksum(b)
int *b;
{
	register i, j;

	j = BSIZE/sizeof(int);
	i = 0;
	do
		i += *b++;
	while (--j);
	if (i != CHECKSUM) {
		printf("Checksum error %o\n", i);
		return(0);
	}
	return(1);
}

checkvol(b, t)
struct spcl *b;
int t;
{
	if (b->c_volume == t)
		return(1);
	return(0);
}

readhdr(b)
struct	spcl *b;
{
	if (gethead(b) == 0)
		return(0);
	if (checktype(b, TS_TAPE) == 0)
		return(0);
	return(1);
}

/*
 * The next routines are called during file extraction to
 * put the data into the right form and place.
 */
#ifndef STANDALONE
xtrfile(b, size)
char	*b;
long	size;
{
	write(ofile, b, (int) size);
}

null() {;}

skip()
{
	lseek(ofile, (long) BSIZE, 1);
}
#endif


rstrfile(b, s)
char *b;
long s;
{
	daddr_t d;

	d = bmap(taddr, curbno);
	dwrite(d, b);
	curbno += 1;
}

rstrskip(b, s)
char *b;
long s;
{
	curbno += 1;
}

#ifndef STANDALONE
putdir(b)
char *b;
{
	register struct direct *dp;
	register i;

	for (dp = (struct direct *) b, i = 0; i < BSIZE; dp++, i += sizeof(*dp)) {
		if (dp->d_ino == 0)
			continue;
		putent((char *) dp);
	}
}
#endif

/*
 * read/write an inode from the disk
 */
getdino(inum, b)
ino_t	inum;
struct	dinode *b;
{
	daddr_t	bno;
	char buf[BSIZE];

	bno = (ino - 1)/INOPB;
	bno += 2;
	dread(bno, buf, BSIZE);
	copy(&buf[((inum-1)%INOPB)*sizeof(struct dinode)], (char *) b, sizeof(struct dinode));
}

putdino(inum, b)
ino_t	inum;
struct	dinode *b;
{
	daddr_t bno;
	char buf[BSIZE];

	bno = ((ino - 1)/INOPB) + 2;
	dread(bno, buf, BSIZE);
	copy((char *) b, &buf[((inum-1)%INOPB)*sizeof(struct dinode)], sizeof(struct dinode));
	dwrite(bno, buf);
}

/*
 * read a bit mask from the tape into m.
 */
readbits(m)
short	*m;
{
	register i;

	i = spcl.c_count;

	while (i--) {
		readtape((char *) m);
		m += (BSIZE/(MLEN/BITS));
	}
	while (gethead(&spcl) == 0)
		;
}

done()
{
#ifndef STANDALONE
	unlink(dirfile);
#endif
	exit(0);
}