Task 134: .DEB File Format
Task 134: .DEB File Format
The .deb file format is a binary package format used primarily in Debian-based Linux distributions. It consists of an ar archive with a specific structure, as detailed in the Debian manual page for deb(5) and Wikipedia entry on the deb file format. The properties intrinsic to this file format, focusing on its structural elements and filesystem-related aspects (such as the encapsulated filesystem tree in the data archive), are as follows:
- AR Archive Magic Header: The fixed string "!\n" (8 bytes), identifying the file as an ar archive.
- Member Headers (for each archive member): A 60-byte header per member, including:
- File name (16 bytes, padded with spaces; may end with '/' for compatibility).
- Timestamp (12 bytes, decimal ASCII representing seconds since Unix epoch).
- Owner ID (6 bytes, decimal ASCII).
- Group ID (6 bytes, decimal ASCII).
- File mode (8 bytes, octal ASCII).
- File size (10 bytes, decimal ASCII).
- End marker (2 bytes: backtick '`' followed by newline '\n').
- debian-binary Member: Contains the format version as a single line of text (e.g., "2.0\n"). Properties include the member's header fields (as above) and the version string.
- control.tar Member: A tar archive (possibly compressed, with filename extensions like .gz, .xz, .zst indicating compression type: gzip, xz, or zstd). Properties include:
- Compression type (derived from filename extension).
- Tar format support: v7, ustar, GNU, or POSIX.
- Contained files and their properties (each tar entry has: name, mode, uid, gid, size, mtime, checksum, typeflag, linkname, magic, version, uname, gname, devmajor, devminor, prefix).
- Key control files and fields (in deb822 format within the 'control' file):
- Package: The package name.
- Version: The package version, possibly including Debian revision.
- Architecture: The target hardware architecture (e.g., amd64, all).
- Maintainer: The package maintainer's name and email.
- Description: A short summary followed by a detailed multi-line description.
- Section: Category of the package (e.g., utils, net).
- Priority: Importance level (e.g., required, optional).
- Installed-Size: Approximate installed size in KiB.
- Depends: List of required dependencies.
- Pre-Depends: Dependencies needed before installation.
- Recommends: Recommended packages.
- Suggests: Suggested packages.
- Enhances: Packages enhanced by this one.
- Breaks: Packages broken by this one.
- Conflicts: Conflicting packages.
- Provides: Virtual packages provided.
- Replaces: Packages replaced.
- Essential: Yes if essential for system operation.
- Protected: Yes if critical for booting or system meta-packages.
- Build-Essential: Yes if required for building other packages.
- Origin: Distribution origin.
- Bugs: URL for bug tracking.
- Homepage: Upstream project URL.
- Tag: Descriptive tags.
- Multi-Arch: Multi-architecture behavior (e.g., same, foreign).
- Source: Source package name and version.
- Other optional files: md5sums (file checksums), conffiles (configuration files), preinst/postinst/prerm/postrm (scripts), config/templates (for debconf).
- data.tar Member: A tar archive (possibly uncompressed or compressed with .gz, .bz2, .lzma, .xz, .zst). This encapsulates the filesystem tree to be installed. Properties include:
- Compression type (derived from filename extension).
- Tar format support: as above.
- Filesystem entries: Each tar entry represents a file, directory, symlink, etc., with properties including name (path relative to root), mode (permissions), uid (owner), gid (group), size, mtime (modification time), typeflag (e.g., regular file, directory), linkname (for symlinks), and content.
Two direct download links for .deb files are:
- https://deb.debian.org/debian/pool/main/h/hello/hello_2.10-3_amd64.deb (hello package for amd64 architecture)
- https://deb.debian.org/debian/pool/main/n/nano/nano_7.2-1+deb12u1_amd64.deb (nano package for amd64 architecture)
Below is an HTML page with embedded JavaScript suitable for embedding in a Ghost blog post. It allows users to drag and drop a .deb file, parses it in the browser (using ArrayBuffer and DataView for binary parsing), and dumps the properties to the screen. Note that this handles basic gzip compression via pako library (included via CDN for simplicity; in production, bundle it). For full write capability, browser limitations apply, but a basic repack stub is included.
Drag and drop .deb file here
- Below is a Python class for handling .deb files. It uses standard library modules (struct, tarfile, gzip, lzma, bz2) to parse, read, decode, print properties, and write (repack with modifications, e.g., updating version). For zstd, external library would be needed, but it handles common types.
import struct
import tarfile
import gzip
import lzma
import bz2
import io
import os
import time
class DebHandler:
def __init__(self):
self.ar_magic = b'!<arch>\n'
self.properties = {}
def open(self, filepath):
with open(filepath, 'rb') as f:
data = f.read()
self.parse(data)
def parse(self, data):
offset = 0
magic = data[offset:offset+8]
if magic != self.ar_magic:
raise ValueError("Not a valid .deb file")
self.properties['magic'] = magic.decode()
offset += 8
self.properties['members'] = []
while offset < len(data):
if data[offset] == 0:
break
name = data[offset:offset+16].decode().rstrip()
timestamp = int(data[offset+16:offset+28].decode().strip())
owner = int(data[offset+28:offset+34].decode().strip())
group = int(data[offset+34:offset+40].decode().strip())
mode = int(data[offset+40:offset+48].decode().strip(), 8)
size = int(data[offset+48:offset+58].decode().strip())
end = data[offset+58:offset+60]
if end != b'`\n':
raise ValueError("Invalid AR header")
offset += 60
content = data[offset:offset+size]
member = {'name': name, 'timestamp': timestamp, 'owner': owner, 'group': group, 'mode': mode, 'size': size, 'content': content}
self.properties['members'].append(member)
offset += size + (size % 2)
if name == 'debian-binary':
self.properties['version'] = content.decode().strip()
elif name.startswith('control.tar'):
self.properties['control_compression'] = name.split('.')[-1] if '.' in name else 'none'
tar_data = self.decompress(content, self.properties['control_compression'])
self.properties['control_files'] = self.parse_tar(tar_data)
control_content = next((f['content'] for f in self.properties['control_files'] if f['name'] == './control'), b'')
self.properties['control_fields'] = self.parse_control(control_content.decode())
elif name.startswith('data.tar'):
self.properties['data_compression'] = name.split('.')[-1] if '.' in name else 'none'
tar_data = self.decompress(content, self.properties['data_compression'])
self.properties['data_files'] = self.parse_tar(tar_data, filesystem=True)
def decompress(self, data, compression):
if compression == 'gz':
return gzip.decompress(data)
elif compression == 'xz':
return lzma.decompress(data)
elif compression == 'bz2':
return bz2.decompress(data)
elif compression == 'none':
return data
else:
raise ValueError(f"Unsupported compression: {compression}")
def parse_tar(self, data, filesystem=False):
files = []
with tarfile.open(fileobj=io.BytesIO(data)) as tar:
for member in tar:
entry = {
'name': member.name,
'mode': member.mode,
'uid': member.uid,
'gid': member.gid,
'size': member.size,
'mtime': member.mtime,
'type': member.type
}
if member.isreg():
entry['content'] = tar.extractfile(member).read()
files.append(entry)
return files
def parse_control(self, content):
fields = {}
lines = content.splitlines()
key = None
for line in lines:
if line.startswith(' '):
if key:
fields[key] += '\n' + line.strip()
elif ':' in line:
key, value = line.split(':', 1)
fields[key.strip()] = value.strip()
return fields
def print_properties(self):
print('DEB Properties:')
print(f"Magic: {self.properties['magic']}")
print(f"Version: {self.properties['version']}")
print(f"Control Compression: {self.properties['control_compression']}")
print('Control Fields:')
for key, value in self.properties['control_fields'].items():
print(f" {key}: {value}")
print(f"Data Compression: {self.properties['data_compression']}")
print('Data Files:')
for file in self.properties['data_files']:
print(f" Path: {file['name']}, Mode: {oct(file['mode'])}, UID: {file['uid']}, GID: {file['gid']}, Size: {file['size']}, MTime: {time.ctime(file['mtime'])}")
def write(self, filepath):
# Example: Repack with modified version
with open(filepath, 'wb') as f:
f.write(self.ar_magic)
for member in self.properties['members']:
if member['name'] == 'debian-binary':
member['content'] = b'2.1\n' # Example modification
member['size'] = len(member['content'])
member['timestamp'] = int(time.time())
header = f"{member['name']:<16}{member['timestamp']:12}{member['owner']:6}{member['group']:6}{oct(member['mode'])[2:]:8}{member['size']:10}`\n".encode()
f.write(header)
f.write(member['content'])
if member['size'] % 2:
f.write(b'\n')
# Full repack would require recompressing tar if modified
# Usage example:
# handler = DebHandler()
# handler.open('example.deb')
# handler.print_properties()
# handler.write('modified.deb')
- Below is a Java class for handling .deb files. It uses java.nio for binary parsing, java.util.zip for gzip, and assumes no external libraries for xz/bz2 (stubbed; use LZMAInputStream or BZip2CompressorInputStream if available). Write method repacks with basic modification.
import java.io.*;
import java.nio.*;
import java.nio.channels.FileChannel;
import java.nio.file.*;
import java.util.*;
import java.util.zip.GZIPInputStream;
import java.util.zip.InflaterInputStream; // For stub
public class DebHandler {
private String arMagic = "!<arch>\n";
private Map<String, Object> properties = new HashMap<>();
public void open(String filepath) throws IOException {
ByteBuffer buffer = ByteBuffer.wrap(Files.readAllBytes(Paths.get(filepath)));
parse(buffer);
}
private void parse(ByteBuffer buffer) {
buffer.order(ByteOrder.LITTLE_ENDIAN);
byte[] magicBytes = new byte[8];
buffer.get(magicBytes);
String magic = new String(magicBytes);
if (!magic.equals(arMagic)) {
throw new IllegalArgumentException("Not a valid .deb file");
}
properties.put("magic", magic);
List<Map<String, Object>> members = new ArrayList<>();
properties.put("members", members);
while (buffer.hasRemaining()) {
if (buffer.get() == 0) break;
buffer.position(buffer.position() - 1);
Map<String, Object> member = parseArHeader(buffer);
byte[] content = new byte[(int) member.get("size")];
buffer.get(content);
member.put("content", content);
members.add(member);
if (((int) member.get("size")) % 2 == 1) buffer.get(); // Pad
String name = (String) member.get("name");
if (name.equals("debian-binary")) {
properties.put("version", new String(content).trim());
} else if (name.startsWith("control.tar")) {
properties.put("controlCompression", name.substring(name.lastIndexOf('.') + 1));
byte[] tarData = decompress(content, (String) properties.get("controlCompression"));
List<Map<String, Object>> controlFiles = parseTar(ByteBuffer.wrap(tarData));
properties.put("controlFiles", controlFiles);
byte[] controlContent = (byte[]) controlFiles.stream()
.filter(f -> ((String) f.get("name")).equals("./control"))
.findFirst().map(f -> f.get("content")).orElse(new byte[0]);
properties.put("controlFields", parseControl(new String(controlContent)));
} else if (name.startsWith("data.tar")) {
properties.put("dataCompression", name.substring(name.lastIndexOf('.') + 1));
byte[] tarData = decompress(content, (String) properties.get("dataCompression"));
List<Map<String, Object>> dataFiles = parseTar(ByteBuffer.wrap(tarData), true);
properties.put("dataFiles", dataFiles);
}
}
}
private Map<String, Object> parseArHeader(ByteBuffer buffer) {
Map<String, Object> header = new HashMap<>();
byte[] nameB = new byte[16]; buffer.get(nameB); header.put("name", new String(nameB).trim());
byte[] tsB = new byte[12]; buffer.get(tsB); header.put("timestamp", Long.parseLong(new String(tsB).trim()));
byte[] ownB = new byte[6]; buffer.get(ownB); header.put("owner", Integer.parseInt(new String(ownB).trim()));
byte[] grpB = new byte[6]; buffer.get(grpB); header.put("group", Integer.parseInt(new String(grpB).trim()));
byte[] modB = new byte[8]; buffer.get(modB); header.put("mode", Integer.parseInt(new String(modB).trim(), 8));
byte[] sizB = new byte[10]; buffer.get(sizB); header.put("size", Integer.parseInt(new String(sizB).trim()));
byte[] endB = new byte[2]; buffer.get(endB); if (!new String(endB).equals("`\n")) throw new IllegalArgumentException("Invalid header");
return header;
}
private byte[] decompress(byte[] data, String type) throws IOException {
if ("gz".equals(type)) {
try (ByteArrayInputStream bais = new ByteArrayInputStream(data);
GZIPInputStream gis = new GZIPInputStream(bais);
ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
byte[] buf = new byte[1024];
int len;
while ((len = gis.read(buf)) > 0) baos.write(buf, 0, len);
return baos.toByteArray();
}
} // Add for xz, bz2 if libraries available
return data;
}
private List<Map<String, Object>> parseTar(ByteBuffer buffer, boolean filesystem) {
List<Map<String, Object>> files = new ArrayList<>();
while (buffer.hasRemaining()) {
byte[] header = new byte[512];
buffer.get(header);
if (Arrays.stream(header).allMatch(b -> b == 0)) break;
Map<String, Object> entry = new HashMap<>();
entry.put("name", new String(Arrays.copyOfRange(header, 0, 100)).trim());
entry.put("mode", Integer.parseInt(new String(Arrays.copyOfRange(header, 100, 108)).trim(), 8));
entry.put("uid", Integer.parseInt(new String(Arrays.copyOfRange(header, 108, 116)).trim(), 8));
entry.put("gid", Integer.parseInt(new String(Arrays.copyOfRange(header, 116, 124)).trim(), 8));
entry.put("size", Integer.parseInt(new String(Arrays.copyOfRange(header, 124, 136)).trim(), 8));
entry.put("mtime", Long.parseLong(new String(Arrays.copyOfRange(header, 136, 148)).trim(), 8));
int size = (int) entry.get("size");
if (size > 0) {
byte[] content = new byte[size];
buffer.get(content);
entry.put("content", content);
}
files.add(entry);
int pad = (512 - (size % 512)) % 512;
buffer.position(buffer.position() + pad);
}
return files;
}
private Map<String, String> parseControl(String content) {
Map<String, String> fields = new HashMap<>();
String[] lines = content.split("\n");
String key = null;
StringBuilder value = new StringBuilder();
for (String line : lines) {
if (line.startsWith(" ")) {
value.append("\n").append(line.trim());
} else if (line.contains(":")) {
if (key != null) fields.put(key, value.toString());
String[] parts = line.split(":", 2);
key = parts[0].trim();
value = new StringBuilder(parts[1].trim());
}
}
if (key != null) fields.put(key, value.toString());
return fields;
}
public void printProperties() {
System.out.println("DEB Properties:");
System.out.println("Magic: " + properties.get("magic"));
System.out.println("Version: " + properties.get("version"));
System.out.println("Control Compression: " + properties.get("controlCompression"));
System.out.println("Control Fields:");
((Map<String, String>) properties.get("controlFields")).forEach((k, v) -> System.out.println(" " + k + ": " + v));
System.out.println("Data Compression: " + properties.get("dataCompression"));
System.out.println("Data Files:");
((List<Map<String, Object>>) properties.get("dataFiles")).forEach(file -> {
System.out.printf(" Path: %s, Mode: %o, UID: %d, GID: %d, Size: %d, MTime: %s%n",
file.get("name"), file.get("mode"), file.get("uid"), file.get("gid"), file.get("size"),
new Date((long) file.get("mtime") * 1000));
});
}
public void write(String filepath) throws IOException {
// Example repack with modified version
try (FileOutputStream fos = new FileOutputStream(filepath)) {
fos.write(arMagic.getBytes());
List<Map<String, Object>> members = (List<Map<String, Object>>) properties.get("members");
for (Map<String, Object> member : members) {
if (member.get("name").equals("debian-binary")) {
member.put("content", "2.1\n".getBytes());
member.put("size", ((byte[]) member.get("content")).length);
member.put("timestamp", System.currentTimeMillis() / 1000);
}
String header = String.format("%-16s%12d%6d%6d%8o%10d`\n",
member.get("name"), member.get("timestamp"), member.get("owner"), member.get("group"),
member.get("mode"), member.get("size"));
fos.write(header.getBytes());
fos.write((byte[]) member.get("content"));
if ((int) member.get("size") % 2 == 1) fos.write('\n');
}
}
// Full write would recompress if modified
}
// Usage example:
// public static void main(String[] args) throws IOException {
// DebHandler handler = new DebHandler();
// handler.open("example.deb");
// handler.printProperties();
// handler.write("modified.deb");
// }
}
- Below is a JavaScript class for Node.js (using fs for file I/O). It parses .deb files, decodes properties, prints to console, and includes a write method. For compression, it uses built-in zlib for gzip (xz/zst require additional modules like lzma-native, stubbed here).
const fs = require('fs');
const zlib = require('zlib');
const tar = require('tar-stream'); // Assume installed; alternatively, manual parse as in browser version
class DebHandler {
constructor() {
this.arMagic = '!<arch>\n';
this.properties = {};
}
open(filepath) {
const data = fs.readFileSync(filepath);
this.parse(data);
}
parse(data) {
let offset = 0;
const magic = data.toString('utf8', offset, offset + 8);
if (magic !== this.arMagic) throw new Error('Not a valid .deb file');
this.properties.magic = magic;
offset += 8;
this.properties.members = [];
while (offset < data.length) {
if (data[offset] === 0) break;
const header = this.parseArHeader(data, offset);
offset += 60;
const content = data.slice(offset, offset + header.size);
this.properties.members.push({...header, content});
offset += header.size + (header.size % 2);
if (header.name === 'debian-binary') {
this.properties.version = content.toString('utf8').trim();
} else if (header.name.startsWith('control.tar')) {
this.properties.controlCompression = header.name.split('.').pop() || 'none';
const tarData = this.decompress(content, this.properties.controlCompression);
this.properties.controlFiles = this.parseTar(tarData);
const controlContent = this.properties.controlFiles.find(f => f.name === './control')?.content.toString('utf8') || '';
this.properties.controlFields = this.parseControl(controlContent);
} else if (header.name.startsWith('data.tar')) {
this.properties.dataCompression = header.name.split('.').pop() || 'none';
const tarData = this.decompress(content, this.properties.dataCompression);
this.properties.dataFiles = this.parseTar(tarData, true);
}
}
}
parseArHeader(data, offset) {
return {
name: data.toString('utf8', offset, offset + 16).trim(),
timestamp: parseInt(data.toString('utf8', offset + 16, offset + 28).trim(), 10),
owner: parseInt(data.toString('utf8', offset + 28, offset + 34).trim(), 10),
group: parseInt(data.toString('utf8', offset + 34, offset + 40).trim(), 10),
mode: parseInt(data.toString('utf8', offset + 40, offset + 48).trim(), 8),
size: parseInt(data.toString('utf8', offset + 48, offset + 58).trim(), 10)
};
}
decompress(data, type) {
if (type === 'gz') return zlib.gunzipSync(data);
// Add for xz, bz2 using additional modules
return data;
}
parseTar(data, filesystem = false) {
const files = [];
const extract = tar.extract();
extract.on('entry', (header, stream, next) => {
const buffers = [];
stream.on('data', chunk => buffers.push(chunk));
stream.on('end', () => {
const entry = {
name: header.name,
mode: header.mode,
uid: header.uid,
gid: header.gid,
size: header.size,
mtime: header.mtime.getTime() / 1000,
type: header.type
};
if (header.type === 'file') entry.content = Buffer.concat(buffers);
files.push(entry);
next();
});
stream.resume();
});
extract.end(data);
return files;
}
parseControl(content) {
const fields = {};
const lines = content.split('\n');
let key = '';
lines.forEach(line => {
if (line.startsWith(' ')) {
if (key) fields[key] += '\n' + line.trim();
} else if (line.includes(':')) {
[key, value] = line.split(':', 2);
fields[key.trim()] = value.trim();
}
});
return fields;
}
printProperties() {
console.log('DEB Properties:');
console.log(`Magic: ${this.properties.magic}`);
console.log(`Version: ${this.properties.version}`);
console.log(`Control Compression: ${this.properties.controlCompression}`);
console.log('Control Fields:');
for (const [key, value] of Object.entries(this.properties.controlFields)) {
console.log(` ${key}: ${value}`);
}
console.log(`Data Compression: ${this.properties.dataCompression}`);
console.log('Data Files:');
this.properties.dataFiles.forEach(file => {
console.log(` Path: ${file.name}, Mode: ${file.mode.toString(8)}, UID: ${file.uid}, GID: ${file.gid}, Size: ${file.size}, MTime: ${new Date(file.mtime * 1000).toISOString()}`);
});
}
write(filepath) {
const output = Buffer.alloc(0);
let buf = Buffer.from(this.arMagic);
this.properties.members.forEach(member => {
if (member.name === 'debian-binary') {
member.content = Buffer.from('2.1\n');
member.size = member.content.length;
member.timestamp = Math.floor(Date.now() / 1000);
}
const header = Buffer.from(
member.name.padEnd(16) +
member.timestamp.toString().padStart(12) +
member.owner.toString().padStart(6) +
member.group.toString().padStart(6) +
member.mode.toString(8).padStart(8) +
member.size.toString().padStart(10) +
'`\n'
);
buf = Buffer.concat([buf, header, member.content]);
if (member.size % 2) buf = Buffer.concat([buf, Buffer.from('\n')]);
});
fs.writeFileSync(filepath, buf);
// Full write would handle tar recompress
}
}
// Usage example:
// const handler = new DebHandler();
// handler.open('example.deb');
// handler.printProperties();
// handler.write('modified.deb');
- Below is a C++ class for handling .deb files. It uses std::ifstream for reading, manual parsing, and zlib for gzip (assume linked; for other compressions, use respective libraries). Write method repacks with modification.
#include <iostream>
#include <fstream>
#include <vector>
#include <map>
#include <string>
#include <iomanip>
#include <ctime>
#include <zlib.h> // For gzip
struct TarEntry {
std::string name;
mode_t mode;
uid_t uid;
gid_t gid;
size_t size;
time_t mtime;
char typeflag;
std::string linkname;
std::vector<char> content;
};
struct ArMember {
std::string name;
time_t timestamp;
uid_t owner;
gid_t group;
mode_t mode;
size_t size;
std::vector<char> content;
};
class DebHandler {
private:
std::string arMagic = "!<arch>\n";
std::map<std::string, std::any> properties;
std::vector<char> decompress(const std::vector<char>& data, const std::string& type) {
if (type == "gz") {
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = data.size();
strm.next_in = (Bytef*)data.data();
inflateInit2(&strm, 15 + 32); // gzip
std::vector<char> out;
char buf[1024];
do {
strm.avail_out = sizeof(buf);
strm.next_out = (Bytef*)buf;
inflate(&strm, Z_NO_FLUSH);
out.insert(out.end(), buf, buf + sizeof(buf) - strm.avail_out);
} while (strm.avail_out == 0);
inflateEnd(&strm);
return out;
}
// Add for xz, bz2
return data;
}
std::vector<TarEntry> parseTar(const std::vector<char>& data) {
std::vector<TarEntry> files;
size_t offset = 0;
while (offset < data.size()) {
const char* header = data.data() + offset;
if (std::all_of(header, header + 512, [](char c){ return c == 0; })) break;
TarEntry entry;
entry.name = std::string(header, 100);
entry.name = entry.name.substr(0, entry.name.find('\0'));
entry.mode = std::stoi(std::string(header + 100, 8), nullptr, 8);
entry.uid = std::stoi(std::string(header + 108, 8), nullptr, 8);
entry.gid = std::stoi(std::string(header + 116, 8), nullptr, 8);
entry.size = std::stoi(std::string(header + 124, 12), nullptr, 8);
entry.mtime = std::stoi(std::string(header + 136, 12), nullptr, 8);
entry.typeflag = header[156];
entry.linkname = std::string(header + 157, 100);
entry.linkname = entry.linkname.substr(0, entry.linkname.find('\0'));
offset += 512;
if (entry.size > 0) {
entry.content.assign(data.begin() + offset, data.begin() + offset + entry.size);
offset += entry.size;
}
offset += (512 - (entry.size % 512)) % 512;
files.push_back(entry);
}
return files;
}
std::map<std::string, std::string> parseControl(const std::string& content) {
std::map<std::string, std::string> fields;
std::istringstream iss(content);
std::string line, key;
while (std::getline(iss, line)) {
if (line[0] == ' ') {
if (!key.empty()) fields[key] += "\n" + line.substr(1);
} else {
size_t pos = line.find(':');
if (pos != std::string::npos) {
key = line.substr(0, pos);
fields[key] = line.substr(pos + 1);
}
}
}
return fields;
}
public:
void open(const std::string& filepath) {
std::ifstream file(filepath, std::ios::binary);
file.seekg(0, std::ios::end);
size_t size = file.tellg();
file.seekg(0);
std::vector<char> data(size);
file.read(data.data(), size);
parse(data);
}
void parse(const std::vector<char>& data) {
size_t offset = 0;
std::string magic(data.begin(), data.begin() + 8);
if (magic != arMagic) throw std::runtime_error("Not a valid .deb file");
properties["magic"] = magic;
offset += 8;
std::vector<ArMember> members;
properties["members"] = members;
while (offset < data.size()) {
if (data[offset] == 0) break;
ArMember member;
member.name = std::string(data.begin() + offset, data.begin() + offset + 16);
member.name.erase(member.name.find_last_not_of(' ') + 1);
member.timestamp = std::stoll(std::string(data.begin() + offset + 16, data.begin() + offset + 28));
member.owner = std::stoi(std::string(data.begin() + offset + 28, data.begin() + offset + 34));
member.group = std::stoi(std::string(data.begin() + offset + 34, data.begin() + offset + 40));
member.mode = std::stoi(std::string(data.begin() + offset + 40, data.begin() + offset + 48), nullptr, 8);
member.size = std::stoll(std::string(data.begin() + offset + 48, data.begin() + offset + 58));
if (std::string(data.begin() + offset + 58, data.begin() + offset + 60) != "`\n") throw std::runtime_error("Invalid header");
offset += 60;
member.content.assign(data.begin() + offset, data.begin() + offset + member.size);
members.push_back(member);
offset += member.size + (member.size % 2);
if (member.name == "debian-binary") {
properties["version"] = std::string(member.content.begin(), member.content.end()).substr(0, member.content.size() - 1);
} else if (member.name.find("control.tar") == 0) {
size_t dot = member.name.rfind('.');
std::string comp = (dot != std::string::npos) ? member.name.substr(dot + 1) : "none";
properties["controlCompression"] = comp;
auto tarData = decompress(member.content, comp);
auto controlFiles = parseTar(tarData);
properties["controlFiles"] = controlFiles;
auto it = std::find_if(controlFiles.begin(), controlFiles.end(), [](const TarEntry& e){ return e.name == "./control"; });
std::string controlContent(it != controlFiles.end() ? std::string(it->content.begin(), it->content.end()) : "");
properties["controlFields"] = parseControl(controlContent);
} else if (member.name.find("data.tar") == 0) {
size_t dot = member.name.rfind('.');
std::string comp = (dot != std::string::npos) ? member.name.substr(dot + 1) : "none";
properties["dataCompression"] = comp;
auto tarData = decompress(member.content, comp);
properties["dataFiles"] = parseTar(tarData);
}
}
}
void printProperties() {
std::cout << "DEB Properties:" << std::endl;
std::cout << "Magic: " << std::any_cast<std::string>(properties["magic"]) << std::endl;
std::cout << "Version: " << std::any_cast<std::string>(properties["version"]) << std::endl;
std::cout << "Control Compression: " << std::any_cast<std::string>(properties["controlCompression"]) << std::endl;
std::cout << "Control Fields:" << std::endl;
auto fields = std::any_cast<std::map<std::string, std::string>>(properties["controlFields"]);
for (const auto& [key, value] : fields) {
std::cout << " " << key << ": " << value << std::endl;
}
std::cout << "Data Compression: " << std::any_cast<std::string>(properties["dataCompression"]) << std::endl;
std::cout << "Data Files:" << std::endl;
auto dataFiles = std::any_cast<std::vector<TarEntry>>(properties["dataFiles"]);
for (const auto& file : dataFiles) {
std::cout << " Path: " << file.name << ", Mode: " << std::oct << file.mode << ", UID: " << std::dec << file.uid
<< ", GID: " << file.gid << ", Size: " << file.size << ", MTime: " << std::ctime(&file.mtime);
}
}
void write(const std::string& filepath) {
std::ofstream out(filepath, std::ios::binary);
out << arMagic;
auto members = std::any_cast<std::vector<ArMember>>(properties["members"]);
for (auto& member : members) {
if (member.name == "debian-binary") {
member.content = {'2', '.', '1', '\n'};
member.size = member.content.size();
member.timestamp = time(nullptr);
}
out << std::left << std::setw(16) << member.name
<< std::right << std::setw(12) << member.timestamp
<< std::setw(6) << member.owner
<< std::setw(6) << member.group
<< std::setw(8) << std::oct << member.mode << std::dec
<< std::setw(10) << member.size
<< "`\n";
out.write(member.content.data(), member.size);
if (member.size % 2) out << '\n';
}
// Full write would handle compression
}
};
// Usage example:
// int main() {
// DebHandler handler;
// handler.open("example.deb");
// handler.printProperties();
// handler.write("modified.deb");
// return 0;
// }