Core: Add RiivolutionPatcher to apply Riivolution-style patches to a game's file system and memory.

Source/Core/DiscIO/CMakeLists.txt

@@ -30,6 +30,8 @@ add_library(discio
   NANDImporter.h
   RiivolutionParser.cpp
   RiivolutionParser.h
+  RiivolutionPatcher.cpp
+  RiivolutionPatcher.h
   ScrubbedBlob.cpp
   ScrubbedBlob.h
   TGCBlob.cpp

Source/Core/DiscIO/RiivolutionPatcher.cpp

@@ -0,0 +1,428 @@
+// Copyright 2021 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "DiscIO/RiivolutionPatcher.h"
+
+#include <algorithm>
+#include <cctype>
+#include <locale>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "Common/FileUtil.h"
+#include "Common/IOFile.h"
+#include "Common/StringUtil.h"
+#include "Core/HW/Memmap.h"
+#include "Core/PowerPC/MMU.h"
+#include "DiscIO/DirectoryBlob.h"
+#include "DiscIO/RiivolutionParser.h"
+
+namespace DiscIO::Riivolution
+{
+// 'before' and 'after' should be two copies of the same source
+// 'split_at' needs to be between the start and end of the source, may not match either boundary
+static void SplitAt(BuilderContentSource* before, BuilderContentSource* after, u64 split_at)
+{
+  const u64 start = before->m_offset;
+  const u64 size = before->m_size;
+  const u64 end = start + size;
+
+  // The source before the split point just needs its length reduced.
+  before->m_size = split_at - start;
+
+  // The source after the split needs its length reduced and its start point adjusted.
+  after->m_offset += before->m_size;
+  after->m_size = end - split_at;
+  if (std::holds_alternative<ContentFile>(after->m_source))
+    std::get<ContentFile>(after->m_source).m_offset += before->m_size;
+  else if (std::holds_alternative<const u8*>(after->m_source))
+    std::get<const u8*>(after->m_source) += before->m_size;
+  else if (std::holds_alternative<ContentPartition>(after->m_source))
+    std::get<ContentPartition>(after->m_source).m_offset += before->m_size;
+  else if (std::holds_alternative<ContentVolume>(after->m_source))
+    std::get<ContentVolume>(after->m_source).m_offset += before->m_size;
+}
+
+static void ApplyPatchToFile(const Patch& patch, DiscIO::FSTBuilderNode* file_node,
+                             std::string external_filename, u64 file_patch_offset,
+                             u64 raw_external_file_offset, u64 file_patch_length, bool resize)
+{
+  ::File::IOFile f(external_filename, "rb");
+  if (!f)
+    return;
+
+  auto& content = std::get<std::vector<BuilderContentSource>>(file_node->m_content);
+
+  const u64 raw_external_filesize = f.GetSize();
+  const u64 external_file_offset = std::min(raw_external_file_offset, raw_external_filesize);
+  const u64 external_filesize = raw_external_filesize - external_file_offset;
+
+  const u64 patch_start = file_patch_offset;
+  const u64 patch_size = file_patch_length == 0 ? external_filesize : file_patch_length;
+  const u64 patch_end = patch_start + patch_size;
+
+  const u64 target_filesize = resize ? patch_end : std::max(file_node->m_size, patch_end);
+
+  size_t insert_where = 0;
+  if (patch_start >= file_node->m_size)
+  {
+    // If the patch is at or past the end of the existing file no existing content needs to be
+    // touched, just extend the file.
+    if (patch_start > file_node->m_size)
+    {
+      // Insert an padding area between the old file and the patch data.
+      content.emplace_back(BuilderContentSource{file_node->m_size, patch_start - file_node->m_size,
+                                                ContentFixedByte{0}});
+    }
+
+    insert_where = content.size();
+  }
+  else
+  {
+    // Patch is at the start or somewhere in the middle of the existing file. At least one source
+    // needs to be modified or removed, and a new source with the patch data inserted instead.
+    // To make this easier, we first split up existing sources at the patch start and patch end
+    // offsets, then discard all overlapping sources and insert the patch sources there.
+    for (size_t i = 0; i < content.size(); ++i)
+    {
+      const u64 source_start = content[i].m_offset;
+      const u64 source_end = source_start + content[i].m_size;
+      if (patch_start > source_start && patch_start < source_end)
+      {
+        content.insert(content.begin() + i + 1, content[i]);
+        SplitAt(&content[i], &content[i + 1], patch_start);
+        continue;
+      }
+      if (patch_end > source_start && patch_end < source_end)
+      {
+        content.insert(content.begin() + i + 1, content[i]);
+        SplitAt(&content[i], &content[i + 1], patch_end);
+      }
+    }
+
+    // Now discard the overlapping areas and remember where they were so we can insert there.
+    for (size_t i = 0; i < content.size(); ++i)
+    {
+      if (patch_start == content[i].m_offset)
+      {
+        insert_where = i;
+        while (i < content.size() && patch_end >= content[i].m_offset + content[i].m_size)
+          ++i;
+        content.erase(content.begin() + insert_where, content.begin() + i);
+        break;
+      }
+    }
+  }
+
+  // Insert the actual patch data.
+  if (patch_size > 0 && external_filesize > 0)
+  {
+    BuilderContentSource source{patch_start, std::min(patch_size, external_filesize),
+                                ContentFile{std::move(external_filename), external_file_offset}};
+    content.emplace(content.begin() + insert_where, std::move(source));
+    ++insert_where;
+  }
+
+  // Pad with zeroes if the patch file is smaller than the patch size.
+  if (external_filesize < patch_size)
+  {
+    BuilderContentSource padding{patch_start + external_filesize, patch_size - external_filesize,
+                                 ContentFixedByte{0}};
+    content.emplace(content.begin() + insert_where, std::move(padding));
+  }
+
+  // Update the filesize of the file.
+  file_node->m_size = target_filesize;
+
+  // Drop any source past the new end of the file -- this can happen on file truncation.
+  while (!content.empty() && content.back().m_offset >= target_filesize)
+    content.pop_back();
+}
+
+static void ApplyPatchToFile(const Patch& patch, const File& file_patch,
+                             DiscIO::FSTBuilderNode* file_node)
+{
+  ApplyPatchToFile(patch, file_node, patch.m_root + "/" + file_patch.m_external,
+                   file_patch.m_offset, file_patch.m_fileoffset, file_patch.m_length,
+                   file_patch.m_resize);
+}
+
+static bool CaseInsensitiveEquals(std::string_view a, std::string_view b)
+{
+  if (a.size() != b.size())
+    return false;
+  return std::equal(a.begin(), a.end(), b.begin(), [](char ca, char cb) {
+    return std::tolower(ca, std::locale::classic()) == std::tolower(cb, std::locale::classic());
+  });
+}
+
+static FSTBuilderNode* FindFileNodeInFST(std::string_view path, std::vector<FSTBuilderNode>* fst,
+                                         bool create_if_not_exists)
+{
+  const size_t path_separator = path.find('/');
+  const bool is_file = path_separator == std::string_view::npos;
+  const std::string_view name = is_file ? path : path.substr(0, path_separator);
+  const auto it = std::find_if(fst->begin(), fst->end(), [&](const FSTBuilderNode& node) {
+    return CaseInsensitiveEquals(node.m_filename, name);
+  });
+
+  if (it == fst->end())
+  {
+    if (!create_if_not_exists)
+      return nullptr;
+
+    if (is_file)
+    {
+      return &fst->emplace_back(
+          DiscIO::FSTBuilderNode{std::string(name), 0, std::vector<BuilderContentSource>()});
+    }
+
+    auto& new_folder = fst->emplace_back(
+        DiscIO::FSTBuilderNode{std::string(name), 0, std::vector<FSTBuilderNode>()});
+    return FindFileNodeInFST(path.substr(path_separator + 1),
+                             &std::get<std::vector<FSTBuilderNode>>(new_folder.m_content), true);
+  }
+
+  const bool is_existing_node_file = it->IsFile();
+  if (is_file != is_existing_node_file)
+    return nullptr;
+  if (is_file)
+    return &*it;
+
+  return FindFileNodeInFST(path.substr(path_separator + 1),
+                           &std::get<std::vector<FSTBuilderNode>>(it->m_content),
+                           create_if_not_exists);
+}
+
+static void FindFilenameNodesInFST(std::vector<DiscIO::FSTBuilderNode*>* nodes_out,
+                                   std::string_view filename, std::vector<FSTBuilderNode>* fst)
+{
+  for (FSTBuilderNode& node : *fst)
+  {
+    if (node.IsFolder())
+    {
+      FindFilenameNodesInFST(nodes_out, filename,
+                             &std::get<std::vector<FSTBuilderNode>>(node.m_content));
+    }
+    else if (node.m_filename == filename)
+    {
+      nodes_out->push_back(&node);
+    }
+  }
+}
+
+static void ApplyFolderPatchToFST(const Patch& patch, const Folder& folder,
+                                  const ::File::FSTEntry& external_files,
+                                  std::string_view disc_path,
+                                  std::vector<DiscIO::FSTBuilderNode>* fst)
+{
+  for (const auto& child : external_files.children)
+  {
+    std::string child_disc_patch = std::string(disc_path) + "/" + child.virtualName;
+    if (child.isDirectory)
+    {
+      ApplyFolderPatchToFST(patch, folder, child, child_disc_patch, fst);
+    }
+    else
+    {
+      DiscIO::FSTBuilderNode* node = FindFileNodeInFST(child_disc_patch, fst, folder.m_create);
+      if (node)
+        ApplyPatchToFile(patch, node, child.physicalName, 0, 0, folder.m_length, folder.m_resize);
+    }
+  }
+}
+
+static void ApplyUnknownFolderPatchToFST(const Patch& patch, const Folder& folder,
+                                         const ::File::FSTEntry& external_files,
+                                         std::vector<DiscIO::FSTBuilderNode>* fst)
+{
+  for (const auto& child : external_files.children)
+  {
+    if (child.isDirectory)
+    {
+      ApplyUnknownFolderPatchToFST(patch, folder, child, fst);
+    }
+    else
+    {
+      std::vector<DiscIO::FSTBuilderNode*> nodes;
+      FindFilenameNodesInFST(&nodes, child.virtualName, fst);
+      for (auto* node : nodes)
+        ApplyPatchToFile(patch, node, child.physicalName, 0, 0, folder.m_length, folder.m_resize);
+    }
+  }
+}
+
+void ApplyPatchesToFiles(const std::vector<Patch>& patches,
+                         std::vector<DiscIO::FSTBuilderNode>* fst, DiscIO::FSTBuilderNode* dol_node)
+{
+  // For file searching purposes, Riivolution assumes that the game's main.dol is in the root of the
+  // file system. So to avoid doing a bunch of special case handling for that, we just put a node
+  // for this into the FST and remove it again after the file patching is done.
+  dol_node->m_filename = "main.dol";
+  fst->push_back(*dol_node);
+
+  for (const auto& patch : patches)
+  {
+    for (const auto& file : patch.m_file_patches)
+    {
+      if (!file.m_disc.empty() && file.m_disc[0] == '/')
+      {
+        // If the disc path starts with a / then we should patch that specific disc path.
+        DiscIO::FSTBuilderNode* node =
+            FindFileNodeInFST(std::string_view(file.m_disc).substr(1), fst, file.m_create);
+        if (node)
+          ApplyPatchToFile(patch, file, node);
+      }
+      else
+      {
+        // Otherwise we want to patch any file on the entire disc matching that filename.
+        std::vector<DiscIO::FSTBuilderNode*> nodes;
+        FindFilenameNodesInFST(&nodes, file.m_disc, fst);
+        for (auto* node : nodes)
+          ApplyPatchToFile(patch, file, node);
+      }
+    }
+
+    for (const auto& folder : patch.m_folder_patches)
+    {
+      ::File::FSTEntry external_files =
+          ::File::ScanDirectoryTree(patch.m_root + "/" + folder.m_external, folder.m_recursive);
+
+      std::string_view disc_path = folder.m_disc;
+      while (StringBeginsWith(disc_path, "/"))
+        disc_path.remove_prefix(1);
+      while (StringEndsWith(disc_path, "/"))
+        disc_path.remove_suffix(1);
+      if (disc_path.empty())
+        ApplyUnknownFolderPatchToFST(patch, folder, external_files, fst);
+      else
+        ApplyFolderPatchToFST(patch, folder, external_files, disc_path, fst);
+    }
+  }
+
+  auto main_dol_node_in_fst =
+      std::find_if(fst->begin(), fst->end(), [&](const DiscIO::FSTBuilderNode& node) {
+        return node.m_filename == "main.dol";
+      });
+  if (main_dol_node_in_fst != fst->end())
+  {
+    *dol_node = *main_dol_node_in_fst;
+    fst->erase(main_dol_node_in_fst);
+  }
+}
+
+static bool MemoryMatchesAt(u32 offset, const std::vector<u8>& value)
+{
+  for (u32 i = 0; i < value.size(); ++i)
+  {
+    auto result = PowerPC::HostTryReadU8(offset + i);
+    if (!result || result->value != value[i])
+      return false;
+  }
+  return true;
+}
+
+static void ApplyMemoryPatch(u32 offset, const std::vector<u8>& value,
+                             const std::vector<u8>& original)
+{
+  if (value.empty())
+    return;
+
+  if (!original.empty() && !MemoryMatchesAt(offset, original))
+    return;
+
+  for (u32 i = 0; i < value.size(); ++i)
+    PowerPC::HostTryWriteU8(value[i], offset + i);
+}
+
+static std::vector<u8> GetMemoryPatchValue(const Patch& patch, const Memory& memory_patch)
+{
+  if (!memory_patch.m_valuefile.empty())
+  {
+    ::File::IOFile f(patch.m_root + "/" + memory_patch.m_valuefile, "rb");
+    if (!f)
+      return {};
+    const u64 length = f.GetSize();
+    std::vector<u8> value;
+    value.resize(length);
+    if (!f.ReadBytes(value.data(), length))
+      return {};
+
+    return value;
+  }
+
+  return memory_patch.m_value;
+}
+
+static void ApplyMemoryPatch(const Patch& patch, const Memory& memory_patch)
+{
+  ApplyMemoryPatch(memory_patch.m_offset | 0x80000000, GetMemoryPatchValue(patch, memory_patch),
+                   memory_patch.m_original);
+}
+
+static void ApplySearchMemoryPatch(const Patch& patch, const Memory& memory_patch)
+{
+  if (memory_patch.m_original.empty())
+    return;
+
+  const u32 ram_size = ::Memory::GetRamSize();
+  const u32 stride = memory_patch.m_align < 1 ? 1 : memory_patch.m_align;
+  for (u32 i = 0; i < ram_size - (stride - 1); i += stride)
+  {
+    const u32 address = i | 0x80000000;
+    if (MemoryMatchesAt(address, memory_patch.m_original))
+    {
+      ApplyMemoryPatch(address, GetMemoryPatchValue(patch, memory_patch), {});
+      break;
+    }
+  }
+}
+
+static void ApplyOcarinaMemoryPatch(const Patch& patch, const Memory& memory_patch)
+{
+  if (memory_patch.m_value.empty())
+    return;
+
+  const u32 ram_size = ::Memory::GetRamSize();
+  for (u32 i = 0; i < ram_size; i += 4)
+  {
+    // first find the pattern
+    const u32 address = i | 0x80000000;
+    if (MemoryMatchesAt(address, memory_patch.m_value))
+    {
+      for (; i < ram_size; i += 4)
+      {
+        // from the pattern find the next blr instruction
+        const u32 blr_address = i | 0x80000000;
+        auto blr = PowerPC::HostTryReadU32(blr_address);
+        if (blr && blr->value == 0x4e800020)
+        {
+          // and replace it with a jump to the given offset
+          const u32 target = memory_patch.m_offset | 0x80000000;
+          const u32 jmp = ((target - blr_address) & 0x03fffffc) | 0x48000000;
+          PowerPC::HostTryWriteU32(jmp, blr_address);
+          return;
+        }
+      }
+      return;
+    }
+  }
+}
+
+void ApplyPatchesToMemory(const std::vector<Patch>& patches)
+{
+  for (const auto& patch : patches)
+  {
+    for (const auto& memory : patch.m_memory_patches)
+    {
+      if (memory.m_ocarina)
+        ApplyOcarinaMemoryPatch(patch, memory);
+      else if (memory.m_search)
+        ApplySearchMemoryPatch(patch, memory);
+      else
+        ApplyMemoryPatch(patch, memory);
+    }
+  }
+}
+}  // namespace DiscIO::Riivolution

Source/Core/DiscIO/RiivolutionPatcher.h

@@ -0,0 +1,21 @@
+// Copyright 2021 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <vector>
+
+#include "DiscIO/RiivolutionParser.h"
+
+namespace DiscIO
+{
+struct FSTBuilderNode;
+}
+
+namespace DiscIO::Riivolution
+{
+void ApplyPatchesToFiles(const std::vector<Patch>& patches,
+                         std::vector<DiscIO::FSTBuilderNode>* fst,
+                         DiscIO::FSTBuilderNode* dol_node);
+void ApplyPatchesToMemory(const std::vector<Patch>& patches);
+}  // namespace DiscIO::Riivolution

Source/Core/DolphinLib.props

@@ -434,6 +434,7 @@
     <ClInclude Include="DiscIO\MultithreadedCompressor.h" />
     <ClInclude Include="DiscIO\NANDImporter.h" />
     <ClInclude Include="DiscIO\RiivolutionParser.h" />
+    <ClInclude Include="DiscIO\RiivolutionPatcher.h" />
     <ClInclude Include="DiscIO\ScrubbedBlob.h" />
     <ClInclude Include="DiscIO\TGCBlob.h" />
     <ClInclude Include="DiscIO\Volume.h" />
@@ -1021,6 +1022,7 @@
     <ClCompile Include="DiscIO\LaggedFibonacciGenerator.cpp" />
     <ClCompile Include="DiscIO\NANDImporter.cpp" />
     <ClCompile Include="DiscIO\RiivolutionParser.cpp" />
+    <ClCompile Include="DiscIO\RiivolutionPatcher.cpp" />
     <ClCompile Include="DiscIO\ScrubbedBlob.cpp" />
     <ClCompile Include="DiscIO\TGCBlob.cpp" />
     <ClCompile Include="DiscIO\Volume.cpp" />