Tape Archive Lister: Tar file
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
/*
Error handling throughout. In particular, the reading code needs to checksum!
Write getInputStream(). Here's how: seek on the file, malloc a buffer
big enough to hold the file, read it into memory, return a
ByteArrayInputStream.
Handle LF_LINK linked files: getEntry(name).getOffset().
Think about writing Tar files?
*/
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Enumeration;
import java.util.Vector;
/**
* Demonstrate the Tar archive lister.
*
* @author Ian F. Darwin, http://www.darwinsys.com/
* @version $Id: TarList.java,v 1.7 2004/03/07 17:47:35 ian Exp $
*/
public class TarList {
public static void main(String[] argv) throws IOException, TarException {
if (argv.length == 0) {
System.err.println("Usage: TarList archive");
System.exit(1);
}
new TarList(argv[0]).list();
}
/** The TarFile we are reading */
TarFile tf;
/** Constructor */
public TarList(String fileName) {
tf = new TarFile(fileName);
}
/** Generate and print the listing */
public void list() throws IOException, TarException {
Enumeration list = tf.entries();
while (list.hasMoreElements()) {
TarEntry e = (TarEntry) list.nextElement();
System.out.println(toListFormat(e));
}
}
protected StringBuffer sb;
/** Shift used in formatting permissions */
protected static int[] shft = { 6, 3, 0 };
/** Format strings used in permissions */
protected static String rwx[] = { "---", "--x", "-w-", "-wx", "r--", "r-x",
"rw-", "rwx" };
/** NumberFormat used in formatting List form string */
NumberFormat sizeForm = new DecimalFormat("00000000");
/** Date used in printing mtime */
Date date = new Date();
SimpleDateFormat dateForm = new SimpleDateFormat("yyyy-MM-dd HH:mm");
/** Format a TarEntry the same way that UNIX tar does */
public String toListFormat(TarEntry e) {
sb = new StringBuffer();
switch (e.type) {
case TarEntry.LF_OLDNORMAL:
case TarEntry.LF_NORMAL:
case TarEntry.LF_CONTIG:
case TarEntry.LF_LINK: // hard link: same as file
sb.append('-'); // 'f' would be sensible
break;
case TarEntry.LF_DIR:
sb.append('d');
break;
case TarEntry.LF_SYMLINK:
sb.append('l');
break;
case TarEntry.LF_CHR: // UNIX character device file
sb.append('c');
break;
case TarEntry.LF_BLK: // UNIX block device file
sb.append('b');
break;
case TarEntry.LF_FIFO: // UNIX named pipe
sb.append('p');
break;
default: // Can't happen?
sb.append('?');
break;
}
// Convert e.g., 754 to rwxrw-r--
int mode = e.getMode();
for (int i = 0; i < 3; i++) {
sb.append(rwx[mode >> shft[i] & 007]);
}
sb.append(' ');
// owner and group
sb.append(e.getUname()).append('/').append(e.getGname()).append(' ');
// size
// DecimalFormat can't do "%-9d", so we do part of it ourselves
sb.append(' ');
String t = sizeForm.format(e.getSize());
boolean digit = false;
char c;
for (int i = 0; i < 8; i++) {
c = t.charAt(i);
if (!digit && i < (8 - 1) && c == '0')
sb.append(' '); // leading space
else {
digit = true;
sb.append(c);
}
}
sb.append(' ');
// mtime
// copy file's mtime into Data object (after scaling
// from "sec since 1970" to "msec since 1970"), and format it.
date.setTime(1000 * e.getTime());
sb.append(dateForm.format(date)).append(' ');
sb.append(e.getName());
if (e.isLink())
sb.append(" link to ").append(e.getLinkName());
if (e.isSymLink())
sb.append(" -> ").append(e.getLinkName());
return sb.toString();
}
}
/**
* One entry in an archive file.
*
* @author Ian Darwin
* @version $Id: TarEntry.java,v 1.7 2004/03/06 21:16:19 ian Exp $
* @note Tar format info taken from John Gilmore's public domain tar program,
* @(#)tar.h 1.21 87/05/01 Public Domain, which said: "Created 25 August 1985 by
* John Gilmore, ihnp4!hoptoad!gnu." John is now gnu@toad.com, and by
* another path tar.h is GPL'd in GNU Tar.
*/
class TarEntry {
/** Where in the tar archive this entry's HEADER is found. */
public long fileOffset = 0;
/** The maximum size of a name */
public static final int NAMSIZ = 100;
public static final int TUNMLEN = 32;
public static final int TGNMLEN = 32;
// Next fourteen fields constitute one physical record.
// Padded to TarFile.RECORDSIZE bytes on tape/disk.
// Lazy Evaluation: just read fields in raw form, only format when asked.
/** File name */
byte[] name = new byte[NAMSIZ];
/** permissions, e.g., rwxr-xr-x? */
byte[] mode = new byte[8];
/* user */
byte[] uid = new byte[8];
/* group */
byte[] gid = new byte[8];
/* size */
byte[] size = new byte[12];
/* UNIX modification time */
byte[] mtime = new byte[12];
/* checksum field */
byte[] chksum = new byte[8];
byte type;
byte[] linkName = new byte[NAMSIZ];
byte[] magic = new byte[8];
byte[] uname = new byte[TUNMLEN];
byte[] gname = new byte[TGNMLEN];
byte[] devmajor = new byte[8];
byte[] devminor = new byte[8];
// End of the physical data fields.
/* The magic field is filled with this if uname and gname are valid. */
public static final byte TMAGIC[] = {
// 'u', 's', 't', 'a', 'r', ' ', ' ', '\0'
0, 0, 0, 0, 0, 0, 0x20, 0x20, 0 }; /* 7 chars and a null */
/* Type value for Normal file, Unix compatibility */
public static final int LF_OLDNORMAL = '\0';
/* Type value for Normal file */
public static final int LF_NORMAL = '0';
/* Type value for Link to previously dumped file */
public static final int LF_LINK = '1';
/* Type value for Symbolic link */
public static final int LF_SYMLINK = '2';
/* Type value for Character special file */
public static final int LF_CHR = '3';
/* Type value for Block special file */
public static final int LF_BLK = '4';
/* Type value for Directory */
public static final int LF_DIR = '5';
/* Type value for FIFO special file */
public static final int LF_FIFO = '6';
/* Type value for Contiguous file */
public static final int LF_CONTIG = '7';
/* Constructor that reads the entry's header. */
public TarEntry(RandomAccessFile is) throws IOException, TarException {
fileOffset = is.getFilePointer();
// read() returns -1 at EOF
if (is.read(name) < 0)
throw new EOFException();
// Tar pads to block boundary with nulls.
if (name[0] == '\0')
throw new EOFException();
// OK, read remaining fields.
is.read(mode);
is.read(uid);
is.read(gid);
is.read(size);
is.read(mtime);
is.read(chksum);
type = is.readByte();
is.read(linkName);
is.read(magic);
is.read(uname);
is.read(gname);
is.read(devmajor);
is.read(devminor);
// Since the tar header is < 512, we need to skip it.
is
.skipBytes((int) (TarFile.RECORDSIZE - (is.getFilePointer() % TarFile.RECORDSIZE)));
// TODO if checksum() fails,
// throw new TarException("Failed to find next header");
}
/** Returns the name of the file this entry represents. */
public String getName() {
return new String(name).trim();
}
public String getTypeName() {
switch (type) {
case LF_OLDNORMAL:
case LF_NORMAL:
return "file";
case LF_LINK:
return "link w/in archive";
case LF_SYMLINK:
return "symlink";
case LF_CHR:
case LF_BLK:
case LF_FIFO:
return "special file";
case LF_DIR:
return "directory";
case LF_CONTIG:
return "contig";
default:
throw new IllegalStateException("TarEntry.getTypeName: type "
+ type + " invalid");
}
}
/** Returns the UNIX-specific "mode" (type+permissions) of the entry */
public int getMode() {
try {
return Integer.parseInt(new String(mode).trim(), 8) & 0777;
} catch (IllegalArgumentException e) {
return 0;
}
}
/** Returns the size of the entry */
public int getSize() {
try {
return Integer.parseInt(new String(size).trim(), 8);
} catch (IllegalArgumentException e) {
return 0;
}
}
/**
* Returns the name of the file this entry is a link to, or null if this
* entry is not a link.
*/
public String getLinkName() {
// if (isLink())
// return null;
return new String(linkName).trim();
}
/** Returns the modification time of the entry */
public long getTime() {
try {
return Long.parseLong(new String(mtime).trim(), 8);
} catch (IllegalArgumentException e) {
return 0;
}
}
/** Returns the string name of the userid */
public String getUname() {
return new String(uname).trim();
}
/** Returns the string name of the group id */
public String getGname() {
return new String(gname).trim();
}
/** Returns the numeric userid of the entry */
public int getuid() {
try {
return Integer.parseInt(new String(uid).trim());
} catch (IllegalArgumentException e) {
return -1;
}
}
/** Returns the numeric gid of the entry */
public int getgid() {
try {
return Integer.parseInt(new String(gid).trim());
} catch (IllegalArgumentException e) {
return -1;
}
}
/** Returns true if this entry represents a file */
boolean isFile() {
return type == LF_NORMAL || type == LF_OLDNORMAL;
}
/** Returns true if this entry represents a directory */
boolean isDirectory() {
return type == LF_DIR;
}
/** Returns true if this a hard link (to a file in the archive) */
boolean isLink() {
return type == LF_LINK;
}
/** Returns true if this a symbolic link */
boolean isSymLink() {
return type == LF_SYMLINK;
}
/** Returns true if this entry represents some type of UNIX special file */
boolean isSpecial() {
return type == LF_CHR || type == LF_BLK || type == LF_FIFO;
}
public String toString() {
return "TarEntry[" + getName() + ']';
}
}
/*
* Exception for TarFile and TarEntry. $Id: TarException.java,v 1.3 1999/10/06
* 15:13:53 ian Exp $
*/
class TarException extends java.io.IOException {
public TarException() {
super();
}
public TarException(String msg) {
super(msg);
}
}
/**
* Tape Archive Lister, patterned loosely after java.util.ZipFile. Since, unlike
* Zip files, there is no central directory, you have to read the entire file
* either to be sure of having a particular file's entry, or to know how many
* entries there are in the archive.
*
* @author Ian Darwin, http://www.darwinsys.com/
* @version $Id: TarFile.java,v 1.12 2004/03/07 17:53:15 ian Exp $
*/
class TarFile {
/** True after we've done the expensive read. */
protected boolean read = false;
/** The list of entries found in the archive */
protected Vector list;
/** Size of header block. */
public static final int RECORDSIZE = 512;
/* Size of each block, in records */
protected int blocking;
/* Size of each block, in bytes */
protected int blocksize;
/** File containing archive */
protected String fileName;
/** Construct (open) a Tar file by name */
public TarFile(String name) {
fileName = name;
list = new Vector();
}
/** Construct (open) a Tar file by File */
public TarFile(java.io.File name) throws IOException {
this(name.getCanonicalPath());
}
/** The main datastream. */
protected RandomAccessFile is;
/**
* Read the Tar archive in its entirety. This is semi-lazy evaluation, in
* that we don't read the file until we need to. A future revision may use
* even lazier evaluation: in getEntry, scan the list and, if not found,
* continue reading! For now, just read the whole file.
*/
protected void readFile() throws IOException, TarException {
is = new RandomAccessFile(fileName, "r");
TarEntry hdr;
try {
do {
hdr = new TarEntry(is);
if (hdr.getSize() < 0) {
System.out.println("Size < 0");
break;
}
// System.out.println(hdr.toString());
list.addElement(hdr);
// Get the size of the entry
int nbytes = hdr.getSize(), diff;
// Round it up to blocksize.
if ((diff = (nbytes % RECORDSIZE)) != 0) {
nbytes += RECORDSIZE - diff;
}
// And skip over the data portion.
// System.out.println("Skipping " + nbytes + " bytes");
is.skipBytes(nbytes);
} while (true);
} catch (EOFException e) {
// OK, just stop reading.
}
// All done, say we've read the contents.
read = true;
}
/* Close the Tar file. */
public void close() {
try {
is.close();
} catch (IOException e) {
// nothing to do
}
}
/* Returns an enumeration of the Tar file entries. */
public Enumeration entries() throws IOException, TarException {
if (!read) {
readFile();
}
return list.elements();
}
/** Returns the Tar entry for the specified name, or null if not found. */
public TarEntry getEntry(String name) {
for (int i = 0; i < list.size(); i++) {
TarEntry e = (TarEntry) list.elementAt(i);
if (name.equals(e.getName()))
return e;
}
return null;
}
/**
* Returns an InputStream for reading the contents of the specified entry
* from the archive. May cause the entire file to be read.
*/
public InputStream getInputStream(TarEntry entry) {
return null;
}
/** Returns the path name of the Tar file. */
public String getName() {
return fileName;
}
/**
* Returns the number of entries in the Tar archive. May cause the entire
* file to be read. XXX Obviously not written yet, sorry.
*/
public int size() {
return 0;
}
}
Related examples in the same category
