tape.c

早期freebsd实现

/*
 * Write out the next block of a file.
 */
static void
xtrfile(buf, size)
	char	*buf;
	long	size;
{

	if (Nflag)
		return;
	if (write(ofile, buf, (int) size) == -1) {
		fprintf(stderr,
		    "write error extracting inode %d, name %s\nwrite: %s\n",
			curfile.ino, curfile.name, strerror(errno));
		done(1);
	}
}

/*
 * Skip over a hole in a file.
 */
/* ARGSUSED */
static void
xtrskip(buf, size)
	char *buf;
	long size;
{

	if (lseek(ofile, size, SEEK_CUR) == -1) {
		fprintf(stderr,
		    "seek error extracting inode %d, name %s\nlseek: %s\n",
			curfile.ino, curfile.name, strerror(errno));
		done(1);
	}
}

/*
 * Collect the next block of a symbolic link.
 */
static void
xtrlnkfile(buf, size)
	char	*buf;
	long	size;
{

	pathlen += size;
	if (pathlen > MAXPATHLEN) {
		fprintf(stderr, "symbolic link name: %s->%s%s; too long %d\n",
		    curfile.name, lnkbuf, buf, pathlen);
		done(1);
	}
	(void) strcat(lnkbuf, buf);
}

/*
 * Skip over a hole in a symbolic link (should never happen).
 */
/* ARGSUSED */
static void
xtrlnkskip(buf, size)
	char *buf;
	long size;
{

	fprintf(stderr, "unallocated block in symbolic link %s\n",
		curfile.name);
	done(1);
}

/*
 * Collect the next block of a bit map.
 */
static void
xtrmap(buf, size)
	char	*buf;
	long	size;
{

	bcopy(buf, map, size);
	map += size;
}

/*
 * Skip over a hole in a bit map (should never happen).
 */
/* ARGSUSED */
static void
xtrmapskip(buf, size)
	char *buf;
	long size;
{

	panic("hole in map\n");
	map += size;
}

/*
 * Noop, when an extraction function is not needed.
 */
/* ARGSUSED */
void
xtrnull(buf, size)
	char *buf;
	long size;
{

	return;
}

/*
 * Read TP_BSIZE blocks from the input.
 * Handle read errors, and end of media.
 */
static void
readtape(buf)
	char *buf;
{
	long rd, newvol, i;
	int cnt, seek_failed;

	if (blkcnt < numtrec) {
		bcopy(&tapebuf[(blkcnt++ * TP_BSIZE)], buf, (long)TP_BSIZE);
		blksread++;
		tpblksread++;
		return;
	}
	for (i = 0; i < ntrec; i++)
		((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
	if (numtrec == 0)
		numtrec = ntrec;
	cnt = ntrec * TP_BSIZE;
	rd = 0;
getmore:
#ifdef RRESTORE
	if (host)
		i = rmtread(&tapebuf[rd], cnt);
	else
#endif
		i = read(mt, &tapebuf[rd], cnt);
	/*
	 * Check for mid-tape short read error.
	 * If found, skip rest of buffer and start with the next.
	 */
	if (!pipein && numtrec < ntrec && i > 0) {
		dprintf(stdout, "mid-media short read error.\n");
		numtrec = ntrec;
	}
	/*
	 * Handle partial block read.
	 */
	if (pipein && i == 0 && rd > 0)
		i = rd;
	else if (i > 0 && i != ntrec * TP_BSIZE) {
		if (pipein) {
			rd += i;
			cnt -= i;
			if (cnt > 0)
				goto getmore;
			i = rd;
		} else {
			/*
			 * Short read. Process the blocks read.
			 */
			if (i % TP_BSIZE != 0)
				vprintf(stdout,
				    "partial block read: %d should be %d\n",
				    i, ntrec * TP_BSIZE);
			numtrec = i / TP_BSIZE;
		}
	}
	/*
	 * Handle read error.
	 */
	if (i < 0) {
		fprintf(stderr, "Tape read error while ");
		switch (curfile.action) {
		default:
			fprintf(stderr, "trying to set up tape\n");
			break;
		case UNKNOWN:
			fprintf(stderr, "trying to resynchronize\n");
			break;
		case USING:
			fprintf(stderr, "restoring %s\n", curfile.name);
			break;
		case SKIP:
			fprintf(stderr, "skipping over inode %d\n",
				curfile.ino);
			break;
		}
		if (!yflag && !reply("continue"))
			done(1);
		i = ntrec * TP_BSIZE;
		bzero(tapebuf, i);
#ifdef RRESTORE
		if (host)
			seek_failed = (rmtseek(i, 1) < 0);
		else
#endif
			seek_failed = (lseek(mt, i, SEEK_CUR) == (off_t)-1);

		if (seek_failed) {
			fprintf(stderr,
			    "continuation failed: %s\n", strerror(errno));
			done(1);
		}
	}
	/*
	 * Handle end of tape.
	 */
	if (i == 0) {
		vprintf(stdout, "End-of-tape encountered\n");
		if (!pipein) {
			newvol = volno + 1;
			volno = 0;
			numtrec = 0;
			getvol(newvol);
			readtape(buf);
			return;
		}
		if (rd % TP_BSIZE != 0)
			panic("partial block read: %d should be %d\n",
				rd, ntrec * TP_BSIZE);
		terminateinput();
		bcopy((char *)&endoftapemark, &tapebuf[rd], (long)TP_BSIZE);
	}
	blkcnt = 0;
	bcopy(&tapebuf[(blkcnt++ * TP_BSIZE)], buf, (long)TP_BSIZE);
	blksread++;
	tpblksread++;
}

static void
findtapeblksize()
{
	register long i;

	for (i = 0; i < ntrec; i++)
		((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
	blkcnt = 0;
#ifdef RRESTORE
	if (host)
		i = rmtread(tapebuf, ntrec * TP_BSIZE);
	else
#endif
		i = read(mt, tapebuf, ntrec * TP_BSIZE);

	if (i <= 0) {
		fprintf(stderr, "tape read error: %s\n", strerror(errno));
		done(1);
	}
	if (i % TP_BSIZE != 0) {
		fprintf(stderr, "Tape block size (%d) %s (%d)\n",
			i, "is not a multiple of dump block size", TP_BSIZE);
		done(1);
	}
	ntrec = i / TP_BSIZE;
	numtrec = ntrec;
	vprintf(stdout, "Tape block size is %d\n", ntrec);
}

void
closemt()
{

	if (mt < 0)
		return;
#ifdef RRESTORE
	if (host)
		rmtclose();
	else
#endif
		(void) close(mt);
}

/*
 * Read the next block from the tape.
 * Check to see if it is one of several vintage headers.
 * If it is an old style header, convert it to a new style header.
 * If it is not any valid header, return an error.
 */
static int
gethead(buf)
	struct s_spcl *buf;
{
	long i;
	union {
		quad_t	qval;
		long	val[2];
	} qcvt;
	union u_ospcl {
		char dummy[TP_BSIZE];
		struct	s_ospcl {
			long	c_type;
			long	c_date;
			long	c_ddate;
			long	c_volume;
			long	c_tapea;
			u_short	c_inumber;
			long	c_magic;
			long	c_checksum;
			struct odinode {
				unsigned short odi_mode;
				u_short	odi_nlink;
				u_short	odi_uid;
				u_short	odi_gid;
				long	odi_size;
				long	odi_rdev;
				char	odi_addr[36];
				long	odi_atime;
				long	odi_mtime;
				long	odi_ctime;
			} c_dinode;
			long	c_count;
			char	c_addr[256];
		} s_ospcl;
	} u_ospcl;

	if (!cvtflag) {
		readtape((char *)buf);
		if (buf->c_magic != NFS_MAGIC) {
			if (swabl(buf->c_magic) != NFS_MAGIC)
				return (FAIL);
			if (!Bcvt) {
				vprintf(stdout, "Note: Doing Byte swapping\n");
				Bcvt = 1;
			}
		}
		if (checksum((int *)buf) == FAIL)
			return (FAIL);
		if (Bcvt)
			swabst((u_char *)"8l4s31l", (u_char *)buf);
		goto good;
	}
	readtape((char *)(&u_ospcl.s_ospcl));
	bzero((char *)buf, (long)TP_BSIZE);
	buf->c_type = u_ospcl.s_ospcl.c_type;
	buf->c_date = u_ospcl.s_ospcl.c_date;
	buf->c_ddate = u_ospcl.s_ospcl.c_ddate;
	buf->c_volume = u_ospcl.s_ospcl.c_volume;
	buf->c_tapea = u_ospcl.s_ospcl.c_tapea;
	buf->c_inumber = u_ospcl.s_ospcl.c_inumber;
	buf->c_checksum = u_ospcl.s_ospcl.c_checksum;
	buf->c_magic = u_ospcl.s_ospcl.c_magic;
	buf->c_dinode.di_mode = u_ospcl.s_ospcl.c_dinode.odi_mode;
	buf->c_dinode.di_nlink = u_ospcl.s_ospcl.c_dinode.odi_nlink;
	buf->c_dinode.di_uid = u_ospcl.s_ospcl.c_dinode.odi_uid;
	buf->c_dinode.di_gid = u_ospcl.s_ospcl.c_dinode.odi_gid;
	buf->c_dinode.di_size = u_ospcl.s_ospcl.c_dinode.odi_size;
	buf->c_dinode.di_rdev = u_ospcl.s_ospcl.c_dinode.odi_rdev;
	buf->c_dinode.di_atime.ts_sec = u_ospcl.s_ospcl.c_dinode.odi_atime;
	buf->c_dinode.di_mtime.ts_sec = u_ospcl.s_ospcl.c_dinode.odi_mtime;
	buf->c_dinode.di_ctime.ts_sec = u_ospcl.s_ospcl.c_dinode.odi_ctime;
	buf->c_count = u_ospcl.s_ospcl.c_count;
	bcopy(u_ospcl.s_ospcl.c_addr, buf->c_addr, (long)256);
	if (u_ospcl.s_ospcl.c_magic != OFS_MAGIC ||
	    checksum((int *)(&u_ospcl.s_ospcl)) == FAIL)
		return(FAIL);
	buf->c_magic = NFS_MAGIC;

good:
	if ((buf->c_dinode.di_size == 0 || buf->c_dinode.di_size > 0xfffffff) &&
	    (buf->c_dinode.di_mode & IFMT) == IFDIR && Qcvt == 0) {
		qcvt.qval = buf->c_dinode.di_size;
		if (qcvt.val[0] || qcvt.val[1]) {
			printf("Note: Doing Quad swapping\n");
			Qcvt = 1;
		}
	}
	if (Qcvt) {
		qcvt.qval = buf->c_dinode.di_size;
		i = qcvt.val[1];
		qcvt.val[1] = qcvt.val[0];
		qcvt.val[0] = i;
		buf->c_dinode.di_size = qcvt.qval;
	}

	switch (buf->c_type) {

	case TS_CLRI:
	case TS_BITS:
		/*
		 * Have to patch up missing information in bit map headers
		 */
		buf->c_inumber = 0;
		buf->c_dinode.di_size = buf->c_count * TP_BSIZE;
		for (i = 0; i < buf->c_count; i++)
			buf->c_addr[i]++;
		break;

	case TS_TAPE:
		if ((buf->c_flags & DR_NEWINODEFMT) == 0)
			oldinofmt = 1;
		/* fall through */
	case TS_END:
		buf->c_inumber = 0;
		break;

	case TS_INODE:
	case TS_ADDR:
		break;

	default:
		panic("gethead: unknown inode type %d\n", buf->c_type);
		break;
	}
	/*
	 * If we are restoring a filesystem with old format inodes, 
	 * copy the uid/gid to the new location.
	 */
	if (oldinofmt) {
		buf->c_dinode.di_uid = buf->c_dinode.di_ouid;
		buf->c_dinode.di_gid = buf->c_dinode.di_ogid;
	}
	if (dflag)
		accthdr(buf);
	return(GOOD);
}

/*
 * Check that a header is where it belongs and predict the next header
 */
static void
accthdr(header)
	struct s_spcl *header;
{
	static ino_t previno = 0x7fffffff;
	static int prevtype;
	static long predict;
	long blks, i;

	if (header->c_type == TS_TAPE) {
		fprintf(stderr, "Volume header (%s inode format) ",
		    oldinofmt ? "old" : "new");
 		if (header->c_firstrec)
 			fprintf(stderr, "begins with record %d",
 				header->c_firstrec);
 		fprintf(stderr, "\n");
		previno = 0x7fffffff;
		return;
	}
	if (previno == 0x7fffffff)
		goto newcalc;
	switch (prevtype) {
	case TS_BITS:
		fprintf(stderr, "Dump mask header");
		break;
	case TS_CLRI:
		fprintf(stderr, "Remove mask header");
		break;
	case TS_INODE:
		fprintf(stderr, "File header, ino %d", previno);
		break;
	case TS_ADDR:
		fprintf(stderr, "File continuation header, ino %d", previno);
		break;
	case TS_END:
		fprintf(stderr, "End of tape header");
		break;
	}
	if (predict != blksread - 1)
		fprintf(stderr, "; predicted %d blocks, got %d blocks",
			predict, blksread - 1);
	fprintf(stderr, "\n");
newcalc:
	blks = 0;
	if (header->c_type != TS_END)
		for (i = 0; i < header->c_count; i++)
			if (header->c_addr[i] != 0)
				blks++;
	predict = blks;
	blksread = 0;
	prevtype = header->c_type;
	previno = header->c_inumber;
}

/*
 * Find an inode header.
 * Complain if had to skip, and complain is set.
 */
static void
findinode(header)
	struct s_spcl *header;
{
	static long skipcnt = 0;
	long i;
	char buf[TP_BSIZE];

	curfile.name = "<name unknown>";
	curfile.action = UNKNOWN;
	curfile.dip = NULL;
	curfile.ino = 0;
	do {
		if (header->c_magic != NFS_MAGIC) {
			skipcnt++;
			while (gethead(header) == FAIL ||
			    header->c_date != dumpdate)
				skipcnt++;
		}
		switch (header->c_type) {

		case TS_ADDR:
			/*
			 * Skip up to the beginning of the next record
			 */
			for (i = 0; i < header->c_count; i++)
				if (header->c_addr[i])
					readtape(buf);
			while (gethead(header) == FAIL ||
			    header->c_date != dumpdate)
				skipcnt++;
			break;

		case TS_INODE:
			curfile.dip = &header->c_dinode;
			curfile.ino = header->c_inumber;
			break;

		case TS_END:
			curfile.ino = maxino;
			break;

		case TS_CLRI:
			curfile.name = "<file removal list>";
			break;

		case TS_BITS:
			curfile.name = "<file dump list>";
			break;

		case TS_TAPE:
			panic("unexpected tape header\n");
			/* NOTREACHED */

		default:
			panic("unknown tape header type %d\n", spcl.c_type);
			/* NOTREACHED */

		}
	} while (header->c_type == TS_ADDR);
	if (skipcnt > 0)
		fprintf(stderr, "resync restore, skipped %d blocks\n", skipcnt);
	skipcnt = 0;
}

static int
checksum(buf)
	register int *buf;
{
	register int i, j;

	j = sizeof(union u_spcl) / sizeof(int);
	i = 0;
	if(!Bcvt) {
		do
			i += *buf++;
		while (--j);
	} else {
		/* What happens if we want to read restore tapes
			for a 16bit int machine??? */
		do 
			i += swabl(*buf++);
		while (--j);
	}
			
	if (i != CHECKSUM) {
		fprintf(stderr, "Checksum error %o, inode %d file %s\n", i,
			curfile.ino, curfile.name);
		return(FAIL);
	}
	return(GOOD);
}

#ifdef RRESTORE
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#if __STDC__
msg(const char *fmt, ...)
#else
msg(fmt, va_alist)
	char *fmt;
	va_dcl
#endif
{
	va_list ap;
#if __STDC__
	va_start(ap, fmt);
#else
	va_start(ap);
#endif
	(void)vfprintf(stderr, fmt, ap);
	va_end(ap);
}
#endif /* RRESTORE */

static u_char *
swabshort(sp, n)
	register u_char *sp;
	register int n;
{
	char c;

	while (--n >= 0) {
		c = sp[0]; sp[0] = sp[1]; sp[1] = c;
		sp += 2;
	}
	return (sp);
}

static u_char *
swablong(sp, n)
	register u_char *sp;
	register int n;
{
	char c;

	while (--n >= 0) {
		c = sp[0]; sp[0] = sp[3]; sp[3] = c;
		c = sp[2]; sp[2] = sp[1]; sp[1] = c;
		sp += 4;
	}
	return (sp);
}

void
swabst(cp, sp)
	register u_char *cp, *sp;
{
	int n = 0;

	while (*cp) {
		switch (*cp) {
		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			n = (n * 10) + (*cp++ - '0');
			continue;
		
		case 's': case 'w': case 'h':
			if (n == 0)
				n = 1;
			sp = swabshort(sp, n);
			break;

		case 'l':
			if (n == 0)
				n = 1;
			sp = swablong(sp, n);
			break;

		default: /* Any other character, like 'b' counts as byte. */
			if (n == 0)
				n = 1;
			sp += n;
			break;
		}
		cp++;
		n = 0;
	}
}

static u_long
swabl(x)
	u_long x;
{
	swabst((u_char *)"l", (u_char *)&x);
	return (x);
}