From 570e9900fd7b8d15c987c7123e324c33a16822e0 Mon Sep 17 00:00:00 2001
From: Joshua Goins <josh@redstrate.com>
Date: Wed, 16 Mar 2022 18:02:39 -0400
Subject: [PATCH] Add installer extract functionality

---
 CMakeLists.txt           |  11 +++-
 include/installextract.h |   5 ++
 src/installextract.cpp   | 115 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 129 insertions(+), 2 deletions(-)
 create mode 100644 include/installextract.h
 create mode 100644 src/installextract.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e599ca1..9386b43 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,7 @@
 project(libxiv)
 
+find_package(fmt)
+
 add_library(libxiv STATIC
         src/fiinparser.cpp
         src/indexparser.cpp
@@ -7,5 +9,10 @@ add_library(libxiv STATIC
         src/gamedata.cpp
         src/compression.cpp
         src/exhparser.cpp
-        src/exdparser.cpp)
-target_include_directories(libxiv PUBLIC include PRIVATE src)
\ No newline at end of file
+        src/exdparser.cpp
+        src/installextract.cpp)
+target_include_directories(libxiv PUBLIC include PRIVATE src)
+target_link_libraries(libxiv PUBLIC
+        unshield
+        fmt::fmt
+        z)
\ No newline at end of file
diff --git a/include/installextract.h b/include/installextract.h
new file mode 100644
index 0000000..3264e92
--- /dev/null
+++ b/include/installextract.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include <string_view>
+
+void extractBootstrapFiles(const std::string_view installer);
\ No newline at end of file
diff --git a/src/installextract.cpp b/src/installextract.cpp
new file mode 100644
index 0000000..0d27b49
--- /dev/null
+++ b/src/installextract.cpp
@@ -0,0 +1,115 @@
+#include "installextract.h"
+
+#include <cstdio>
+#include <stdexcept>
+#include <libunshield.h>
+#include <fmt/format.h>
+
+const std::array filesToExtract = {"data1.cab", "data1.hdr", "data2.cab"};
+
+const std::array bootComponent = {
+        "cef_license.txt",
+        "FFXIV.ico",
+        "ffxivboot.exe",
+        "ffxivboot.ver",
+        "ffxivboot64.exe",
+        "ffxivconfig.exe",
+        "ffxivconfig64.exe",
+        "ffxivlauncher.exe",
+        "ffxivlauncher64.exe",
+        "ffxivsysinfo.exe",
+        "ffxivsysinfo64.exe",
+        "ffxivupdater.exe",
+        "ffxivupdater64.exe",
+        "FFXIV_sysinfo.ico",
+        "icudt.dll",
+        "libcef.dll",
+        "license.txt",
+        "locales/reserved.txt"
+};
+
+const std::array gameComponent = {
+        "ffxivgame.ver"
+};
+
+void extractBootstrapFiles(const std::string_view installer) {
+    FILE* file = fopen(installer.data(), "rb");
+    if(file == nullptr) {
+        throw std::runtime_error("Failed to open installer {}" + std::string(installer));
+    }
+
+    fseek(file, 0, SEEK_END);
+    size_t fileSize = ftell(file);
+    rewind(file);
+
+    auto buffer = static_cast<char*>(malloc(sizeof(char) * fileSize));
+
+    fread(buffer, 1, fileSize, file);
+
+    // some really, really bad code to basically read the cab files which are put right next to each other in the exe file
+    char* lastNeedle = nullptr;
+    std::string lastFilename;
+    for(auto fileName : filesToExtract) {
+        // all files are located in Disk1
+        const std::string realFileName = fmt::format("Disk1\\{}", fileName);
+        const char* needle = realFileName.c_str();
+
+        // make unshield shut up
+        unshield_set_log_level(0);
+
+        // TODO: is this while really needed? it should only find it once
+        while(true) {
+            char* p = static_cast<char*>(memmem(buffer, fileSize, needle, realFileName.length()));
+            if(!p)
+                break;
+
+            if(lastNeedle != nullptr) {
+                FILE* newFile = fopen(lastFilename.data(), "wb");
+
+                if(lastFilename == "data1.hdr") {
+                    fwrite(lastNeedle + 30, p - lastNeedle - 42, 1, newFile);
+                } else {
+                    fwrite(lastNeedle + 32, p - lastNeedle - 42, 1, newFile);
+                }
+
+                // actual cab files start 32 bytes and we need to peel 42 bytes off of the end
+                fclose(newFile);
+            }
+
+            lastFilename = fileName;
+            lastNeedle = p;
+            fileSize -= (p + 4) - buffer;
+        }
+
+        // write final file
+        FILE* newFile = fopen(lastFilename.data(), "wb");
+        fmt::print("Wrote {}!\n", lastFilename);
+        fwrite(lastNeedle + 33, fileSize - 42, 1, newFile);
+
+        // actual cab files start 32 bytes and we need to peel 42 bytes off of the end
+        fclose(newFile);
+    }
+
+    auto unshield = unshield_open("data1.cab");
+    const int fileCount = unshield_file_count(unshield);
+
+    for(int i = 0 ; i < fileCount; i++) {
+        const char* filename = unshield_file_name(unshield, i);
+
+        for(auto bootName : bootComponent) {
+            fmt::print("Extracted {}\n", bootName);
+
+            if(strcmp(filename, bootName) == 0)
+                unshield_file_save(unshield, i, bootName);
+        }
+
+        for(auto gameName : gameComponent) {
+            fmt::print("Extracted {}\n", gameName);
+
+            if(strcmp(filename, gameName) == 0)
+                unshield_file_save(unshield, i, gameName);
+        }
+    }
+
+    fclose(file);
+}
\ No newline at end of file