Made tar.gz parser

Signed-off-by: Trial97 <alexandru.tripon97@gmail.com>

launcher/Untar.cpp

@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  Prism Launcher - Minecraft Launcher
+ *  Copyright (c) 2023-2024 Trial97 <alexandru.tripon97@gmail.com>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+#include "Untar.h"
+#include <qfileinfo.h>
+#include <qlogging.h>
+#include <quagzipfile.h>
+#include <QByteArray>
+#include <QIODevice>
+#include <QString>
+#include <cstdlib>
+#include "FileSystem.h"
+
+// adaptation of the:
+// - https://github.com/madler/zlib/blob/develop/contrib/untgz/untgz.c
+// - https://en.wikipedia.org/wiki/Tar_(computing)
+// - https://github.com/euroelessar/cutereader/blob/master/karchive/src/ktar.cpp
+
+#define BLOCKSIZE 512
+#define SHORTNAMESIZE 100
+
+enum class TypeFlag : char {
+    Regular = '0',     // regular file
+    ARegular = 0,      // regular file
+    Link = '1',        // link
+    Symlink = '2',     // reserved
+    Character = '3',   // character special
+    Block = '4',       // block special
+    Directory = '5',   // directory
+    FIFO = '6',        // FIFO special
+    Contiguous = '7',  // reserved
+    // Posix stuff
+    GlobalPosixHeader = 'g',
+    ExtendedPosixHeader = 'x',
+    // 'A'– 'Z' Vendor specific extensions(POSIX .1 - 1988)
+    // GNU
+    GNULongLink = 'K', /* long link name */
+    GNULongName = 'L', /* long file name */
+};
+
+struct Header {         /* byte offset */
+    char name[100];     /*   0 */
+    char mode[8];       /* 100 */
+    char uid[8];        /* 108 */
+    char gid[8];        /* 116 */
+    char size[12];      /* 124 */
+    char mtime[12];     /* 136 */
+    char chksum[8];     /* 148 */
+    TypeFlag typeflag;  /* 156 */
+    char linkname[100]; /* 157 */
+    char magic[6];      /* 257 */
+    char version[2];    /* 263 */
+    char uname[32];     /* 265 */
+    char gname[32];     /* 297 */
+    char devmajor[8];   /* 329 */
+    char devminor[8];   /* 337 */
+    char prefix[155];   /* 345 */
+                        /* 500 */
+};
+
+union Buffer {
+    char buffer[BLOCKSIZE];
+    struct Header header;
+};
+
+bool readLonglink(QIODevice* in, Buffer buffer, QByteArray& longlink)
+{
+    qint64 n = 0;
+    qint64 size = strtoll(buffer.header.size, NULL, 8);
+    size--;  // ignore trailing null
+    if (errno == ERANGE) {
+        qCritical() << "The filename size can't be read";
+        return false;
+    }
+    if (size < 0) {
+        qCritical() << "The filename size is negative";
+        return false;
+    }
+    longlink.resize(size + (BLOCKSIZE - size % BLOCKSIZE));  // make the size divisible by BLOCKSIZE
+    for (qint64 offset = 0; offset < longlink.size(); offset += BLOCKSIZE) {
+        n = in->read(longlink.data() + offset, BLOCKSIZE);
+        if (n != BLOCKSIZE) {
+            qCritical() << "The expected blocksize was not respected for the name";
+            return false;
+        }
+    }
+    longlink.truncate(qstrlen(longlink.constData()));
+    return true;
+}
+
+bool Tar::extract(QIODevice* in, QString dst)
+{
+    Buffer buffer;
+    QString name, symlink, firstFolderName;
+    bool doNotReset = false;
+    while (true) {
+        auto n = in->read(buffer.buffer, BLOCKSIZE);
+        if (n != BLOCKSIZE) {  // allways expect complete blocks
+            qCritical() << "The expected blocksize was not respected";
+            return false;
+        }
+        if (buffer.header.name[0] == 0) {  // end of archive
+            return true;
+        }
+        int mode = strtol(buffer.header.mode, NULL, 8) | QFile::ReadUser | QFile::WriteUser;  // hack to ensure write and read permisions
+        if (errno == ERANGE) {
+            qCritical() << "The file mode can't be read";
+            return false;
+        }
+        // there are names that are exactly 100 bytes long
+        // and neither longlink nor \0 terminated (bug:101472)
+        if (name.isEmpty()) {
+            name = QFile::decodeName(QByteArray(buffer.header.name, qstrnlen(buffer.header.name, 100)));
+            if (!firstFolderName.isEmpty() && name.startsWith(firstFolderName)) {
+                name = name.mid(firstFolderName.size());
+            }
+        }
+        if (symlink.isEmpty())
+            symlink = QFile::decodeName(QByteArray(buffer.header.linkname, qstrnlen(buffer.header.linkname, 100)));
+        switch (buffer.header.typeflag) {
+            case TypeFlag::Regular:
+                /* fallthrough */
+            case TypeFlag::ARegular: {
+                auto fileName = FS::PathCombine(dst, name);
+                if (!FS::ensureFilePathExists(fileName)) {
+                    qCritical() << "Can't ensure the file path to exist: " << fileName;
+                    return false;
+                }
+                QFile out(fileName);
+                if (!out.open(QFile::WriteOnly, QFile::Permission(mode))) {
+                    qCritical() << "Can't open file:" << fileName;
+                    return false;
+                }
+                qint64 size = strtoll(buffer.header.size, NULL, 8);
+                if (errno == ERANGE) {
+                    qCritical() << "The file size can't be read";
+                    return false;
+                }
+                while (size > 0) {
+                    QByteArray tmp(BLOCKSIZE, 0);
+                    n = in->read(tmp.data(), BLOCKSIZE);
+                    if (n != BLOCKSIZE) {
+                        qCritical() << "The expected blocksize was not respected when reading file";
+                        return false;
+                    }
+                    tmp.truncate(qMin(BLOCKSIZE, size));
+                    out.write(tmp);
+                    size -= BLOCKSIZE;
+                }
+                QFile::setPermissions(fileName, QFile::Permissions(mode));
+                break;
+            }
+            case TypeFlag::Directory: {
+                if (firstFolderName.isEmpty()) {
+                    firstFolderName = name;
+                    break;
+                }
+                auto folderPath = FS::PathCombine(dst, name);
+                if (!FS::ensureFolderPathExists(folderPath)) {
+                    qCritical() << "Can't ensure that folder exists: " << folderPath;
+                    return false;
+                }
+                break;
+            }
+            case TypeFlag::GNULongLink: {
+                doNotReset = true;
+                QByteArray longlink;
+                if (readLonglink(in, buffer, longlink)) {
+                    symlink = QFile::decodeName(longlink.constData());
+                } else {
+                    qCritical() << "Failed to read long link";
+                    return false;
+                }
+                break;
+            }
+            case TypeFlag::GNULongName: {
+                doNotReset = true;
+                QByteArray longlink;
+                if (readLonglink(in, buffer, longlink)) {
+                    name = QFile::decodeName(longlink.constData());
+                } else {
+                    qCritical() << "Failed to read long name";
+                    return false;
+                }
+                break;
+            }
+            case TypeFlag::Link:
+                /* fallthrough */
+            case TypeFlag::Symlink: {
+                auto fileName = FS::PathCombine(dst, name);
+                if (!FS::create_link(FS::PathCombine(QFileInfo(fileName).path(), symlink), fileName)()) {  // do not use symlinks
+                    qCritical() << "Can't create link for:" << fileName << " to:" << FS::PathCombine(QFileInfo(fileName).path(), symlink);
+                    return false;
+                }
+                FS::ensureFilePathExists(fileName);
+                QFile::setPermissions(fileName, QFile::Permissions(mode));
+                break;
+            }
+            case TypeFlag::Character:
+                /* fallthrough */
+            case TypeFlag::Block:
+                /* fallthrough */
+            case TypeFlag::FIFO:
+                /* fallthrough */
+            case TypeFlag::Contiguous:
+                /* fallthrough */
+            case TypeFlag::GlobalPosixHeader:
+                /* fallthrough */
+            case TypeFlag::ExtendedPosixHeader:
+                /* fallthrough */
+            default:
+                break;
+        }
+        if (!doNotReset) {
+            name.truncate(0);
+            symlink.truncate(0);
+        }
+        doNotReset = false;
+    }
+    return true;
+}
+
+bool GZTar::extract(QString src, QString dst)
+{
+    QuaGzipFile a(src);
+    if (!a.open(QIODevice::ReadOnly)) {
+        qCritical() << "Can't open tar file:" << src;
+        return false;
+    }
+    return Tar::extract(&a, dst);
+}