file_sys: Port Atmosphere-NX fs_mitm implementation

2 files changed, 474 insertions, 0 deletions

diff --git a/src/core/file_sys/fsmitm_romfsbuild.cpp b/src/core/file_sys/fsmitm_romfsbuild.cpp
new file mode 100644
index 000000000..a6fe6719d
--- /dev/null
+++ b/src/core/file_sys/fsmitm_romfsbuild.cpp
@@ -0,0 +1,368 @@
+/*
+ * Copyright (c) 2018 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Adapted by DarkLordZach for use/interaction with yuzu
+ *
+ * Modifications Copyright 2018 yuzu emulator team
+ * Licensed under GPLv2 or any later version
+ * Refer to the license.txt file included.
+ */
+
+#include <cstring>
+#include "common/assert.h"
+#include "fsmitm_romfsbuild.hpp"
+#include "vfs.h"
+#include "vfs_vector.h"
+
+namespace FileSys {
+
+constexpr u64 FS_MAX_PATH = 0x301;
+
+constexpr u32 ROMFS_ENTRY_EMPTY = 0xFFFFFFFF;
+constexpr u32 ROMFS_FILEPARTITION_OFS = 0x200;
+
+/* Types for building a RomFS. */
+struct RomFSHeader {
+    u64 header_size;
+    u64 dir_hash_table_ofs;
+    u64 dir_hash_table_size;
+    u64 dir_table_ofs;
+    u64 dir_table_size;
+    u64 file_hash_table_ofs;
+    u64 file_hash_table_size;
+    u64 file_table_ofs;
+    u64 file_table_size;
+    u64 file_partition_ofs;
+};
+static_assert(sizeof(RomFSHeader) == 0x50, "RomFSHeader has incorrect size.");
+
+struct RomFSDirectoryEntry {
+    u32 parent;
+    u32 sibling;
+    u32 child;
+    u32 file;
+    u32 hash;
+    u32 name_size;
+    char name[];
+};
+static_assert(sizeof(RomFSDirectoryEntry) == 0x18, "RomFSDirectoryEntry has incorrect size.");
+
+struct RomFSFileEntry {
+    u32 parent;
+    u32 sibling;
+    u64 offset;
+    u64 size;
+    u32 hash;
+    u32 name_size;
+    char name[];
+};
+static_assert(sizeof(RomFSFileEntry) == 0x20, "RomFSFileEntry has incorrect size.");
+
+struct RomFSBuildFileContext;
+
+struct RomFSBuildDirectoryContext {
+    char* path;
+    u32 cur_path_ofs;
+    u32 path_len;
+    u32 entry_offset = 0;
+    RomFSBuildDirectoryContext* parent = nullptr;
+    RomFSBuildDirectoryContext* child = nullptr;
+    RomFSBuildDirectoryContext* sibling = nullptr;
+    RomFSBuildFileContext* file = nullptr;
+};
+
+struct RomFSBuildFileContext {
+    char* path;
+    u32 cur_path_ofs;
+    u32 path_len;
+    u32 entry_offset = 0;
+    u64 offset = 0;
+    u64 size = 0;
+    RomFSBuildDirectoryContext* parent = nullptr;
+    RomFSBuildFileContext* sibling = nullptr;
+    VirtualFile source = nullptr;
+};
+
+void RomFSBuildContext::VisitDirectory(VirtualDir root_romfs, RomFSBuildDirectoryContext* parent) {
+    std::vector<RomFSBuildDirectoryContext*> child_dirs;
+
+    VirtualDir dir;
+
+    if (parent->path_len == 0)
+        dir = root_romfs;
+    else
+        dir = root_romfs->GetDirectoryRelative(parent->path);
+
+    const auto entries = dir->GetEntries();
+
+    for (const auto& kv : entries) {
+        if (kv.second == VfsEntryType::Directory) {
+            RomFSBuildDirectoryContext* child = new RomFSBuildDirectoryContext({0});
+            /* Set child's path. */
+            child->cur_path_ofs = parent->path_len + 1;
+            child->path_len = child->cur_path_ofs + kv.first.size();
+            child->path = new char[child->path_len + 1];
+            strcpy(child->path, parent->path);
+            ASSERT(child->path_len < FS_MAX_PATH);
+            strcat(child->path + parent->path_len, "/");
+            strcat(child->path + parent->path_len, kv.first.c_str());
+
+            if (!this->AddDirectory(parent, child, nullptr)) {
+                delete child->path;
+                delete child;
+            } else {
+                child_dirs.push_back(child);
+            }
+        } else {
+            RomFSBuildFileContext* child = new RomFSBuildFileContext({0});
+            /* Set child's path. */
+            child->cur_path_ofs = parent->path_len + 1;
+            child->path_len = child->cur_path_ofs + kv.first.size();
+            child->path = new char[child->path_len + 1];
+            strcpy(child->path, parent->path);
+            ASSERT(child->path_len < FS_MAX_PATH);
+            strcat(child->path + parent->path_len, "/");
+            strcat(child->path + parent->path_len, kv.first.c_str());
+
+            child->source = root_romfs->GetFileRelative(child->path);
+
+            child->size = child->source->GetSize();
+
+            if (!this->AddFile(parent, child)) {
+                delete child->path;
+                delete child;
+            }
+        }
+    }
+
+    for (auto& child : child_dirs) {
+        this->VisitDirectory(root_romfs, child);
+    }
+}
+
+bool RomFSBuildContext::AddDirectory(RomFSBuildDirectoryContext* parent_dir_ctx,
+                                     RomFSBuildDirectoryContext* dir_ctx,
+                                     RomFSBuildDirectoryContext** out_dir_ctx) {
+    /* Check whether it's already in the known directories. */
+    auto existing = this->directories.find(dir_ctx->path);
+    if (existing != this->directories.end()) {
+        if (out_dir_ctx) {
+            *out_dir_ctx = existing->second;
+        }
+        return false;
+    }
+
+    /* Add a new directory. */
+    this->num_dirs++;
+    this->dir_table_size +=
+        sizeof(RomFSDirectoryEntry) + ((dir_ctx->path_len - dir_ctx->cur_path_ofs + 3) & ~3);
+    dir_ctx->parent = parent_dir_ctx;
+    this->directories.insert({dir_ctx->path, dir_ctx});
+
+    if (out_dir_ctx) {
+        *out_dir_ctx = dir_ctx;
+    }
+    return true;
+}
+
+bool RomFSBuildContext::AddFile(RomFSBuildDirectoryContext* parent_dir_ctx,
+                                RomFSBuildFileContext* file_ctx) {
+    /* Check whether it's already in the known files. */
+    auto existing = this->files.find(file_ctx->path);
+    if (existing != this->files.end()) {
+        return false;
+    }
+
+    /* Add a new file. */
+    this->num_files++;
+    this->file_table_size +=
+        sizeof(RomFSFileEntry) + ((file_ctx->path_len - file_ctx->cur_path_ofs + 3) & ~3);
+    file_ctx->parent = parent_dir_ctx;
+    this->files.insert({file_ctx->path, file_ctx});
+
+    return true;
+}
+
+RomFSBuildContext::RomFSBuildContext(VirtualDir base_) : base(std::move(base_)) {
+    this->root = new RomFSBuildDirectoryContext({0});
+    this->root->path = new char[1];
+    this->root->path[0] = '\x00';
+    this->directories.insert({this->root->path, this->root});
+    this->num_dirs = 1;
+    this->dir_table_size = 0x18;
+
+    VisitDirectory(base, this->root);
+}
+
+std::map<u64, VirtualFile> RomFSBuildContext::Build() {
+    std::map<u64, VirtualFile> out;
+    RomFSBuildFileContext* cur_file;
+    RomFSBuildDirectoryContext* cur_dir;
+
+    const auto dir_hash_table_entry_count = romfs_get_hash_table_count(this->num_dirs);
+    const auto file_hash_table_entry_count = romfs_get_hash_table_count(this->num_files);
+    this->dir_hash_table_size = 4 * dir_hash_table_entry_count;
+    this->file_hash_table_size = 4 * file_hash_table_entry_count;
+
+    /* Assign metadata pointers */
+    RomFSHeader* header = new RomFSHeader({0});
+    auto metadata = new u8[this->dir_hash_table_size + this->dir_table_size +
+                           this->file_hash_table_size + this->file_table_size];
+    auto dir_hash_table = reinterpret_cast<u32*>(metadata);
+    const auto dir_table = reinterpret_cast<RomFSDirectoryEntry*>(
+        reinterpret_cast<uintptr_t>(dir_hash_table) + this->dir_hash_table_size);
+    auto file_hash_table =
+        reinterpret_cast<u32*>(reinterpret_cast<uintptr_t>(dir_table) + this->dir_table_size);
+    const auto file_table = reinterpret_cast<RomFSFileEntry*>(
+        reinterpret_cast<uintptr_t>(file_hash_table) + this->file_hash_table_size);
+
+    /* Clear out hash tables. */
+    for (u32 i = 0; i < dir_hash_table_entry_count; i++)
+        dir_hash_table[i] = ROMFS_ENTRY_EMPTY;
+    for (u32 i = 0; i < file_hash_table_entry_count; i++)
+        file_hash_table[i] = ROMFS_ENTRY_EMPTY;
+
+    out.clear();
+
+    /* Determine file offsets. */
+    u32 entry_offset = 0;
+    RomFSBuildFileContext* prev_file = nullptr;
+    for (const auto& it : this->files) {
+        cur_file = it.second;
+        this->file_partition_size = (this->file_partition_size + 0xFULL) & ~0xFULL;
+        cur_file->offset = this->file_partition_size;
+        this->file_partition_size += cur_file->size;
+        cur_file->entry_offset = entry_offset;
+        entry_offset +=
+            sizeof(RomFSFileEntry) + ((cur_file->path_len - cur_file->cur_path_ofs + 3) & ~3);
+        prev_file = cur_file;
+    }
+    /* Assign deferred parent/sibling ownership. */
+    for (auto it = this->files.rbegin(); it != this->files.rend(); it++) {
+        cur_file = it->second;
+        cur_file->sibling = cur_file->parent->file;
+        cur_file->parent->file = cur_file;
+    }
+
+    /* Determine directory offsets. */
+    entry_offset = 0;
+    for (const auto& it : this->directories) {
+        cur_dir = it.second;
+        cur_dir->entry_offset = entry_offset;
+        entry_offset +=
+            sizeof(RomFSDirectoryEntry) + ((cur_dir->path_len - cur_dir->cur_path_ofs + 3) & ~3);
+    }
+    /* Assign deferred parent/sibling ownership. */
+    for (auto it = this->directories.rbegin(); it->second != this->root; it++) {
+        cur_dir = it->second;
+        cur_dir->sibling = cur_dir->parent->child;
+        cur_dir->parent->child = cur_dir;
+    }
+
+    /* Populate file tables. */
+    for (const auto& it : this->files) {
+        cur_file = it.second;
+        RomFSFileEntry* cur_entry = romfs_get_fentry(file_table, cur_file->entry_offset);
+
+        cur_entry->parent = cur_file->parent->entry_offset;
+        cur_entry->sibling =
+            (cur_file->sibling == nullptr) ? ROMFS_ENTRY_EMPTY : cur_file->sibling->entry_offset;
+        cur_entry->offset = cur_file->offset;
+        cur_entry->size = cur_file->size;
+
+        const auto name_size = cur_file->path_len - cur_file->cur_path_ofs;
+        const auto hash = romfs_calc_path_hash(cur_file->parent->entry_offset,
+                                               reinterpret_cast<unsigned char*>(cur_file->path) +
+                                                   cur_file->cur_path_ofs,
+                                               0, name_size);
+        cur_entry->hash = file_hash_table[hash % file_hash_table_entry_count];
+        file_hash_table[hash % file_hash_table_entry_count] = cur_file->entry_offset;
+
+        cur_entry->name_size = name_size;
+        memset(cur_entry->name, 0, (cur_entry->name_size + 3) & ~3);
+        memcpy(cur_entry->name, cur_file->path + cur_file->cur_path_ofs, name_size);
+
+        out.emplace(cur_file->offset + ROMFS_FILEPARTITION_OFS, cur_file->source);
+    }
+
+    /* Populate dir tables. */
+    for (const auto& it : this->directories) {
+        cur_dir = it.second;
+        RomFSDirectoryEntry* cur_entry = romfs_get_direntry(dir_table, cur_dir->entry_offset);
+        cur_entry->parent = cur_dir == this->root ? 0 : cur_dir->parent->entry_offset;
+        cur_entry->sibling =
+            (cur_dir->sibling == nullptr) ? ROMFS_ENTRY_EMPTY : cur_dir->sibling->entry_offset;
+        cur_entry->child =
+            (cur_dir->child == nullptr) ? ROMFS_ENTRY_EMPTY : cur_dir->child->entry_offset;
+        cur_entry->file =
+            (cur_dir->file == nullptr) ? ROMFS_ENTRY_EMPTY : cur_dir->file->entry_offset;
+
+        u32 name_size = cur_dir->path_len - cur_dir->cur_path_ofs;
+        u32 hash = romfs_calc_path_hash(
+            cur_dir == this->root ? 0 : cur_dir->parent->entry_offset,
+            reinterpret_cast<unsigned char*>(cur_dir->path) + cur_dir->cur_path_ofs, 0, name_size);
+        cur_entry->hash = dir_hash_table[hash % dir_hash_table_entry_count];
+        dir_hash_table[hash % dir_hash_table_entry_count] = cur_dir->entry_offset;
+
+        cur_entry->name_size = name_size;
+        memset(cur_entry->name, 0, (cur_entry->name_size + 3) & ~3);
+        memcpy(cur_entry->name, cur_dir->path + cur_dir->cur_path_ofs, name_size);
+    }
+
+    /* Delete directories. */
+    for (const auto& it : this->directories) {
+        cur_dir = it.second;
+        delete cur_dir->path;
+        delete cur_dir;
+    }
+    this->root = nullptr;
+    this->directories.clear();
+
+    /* Delete files. */
+    for (const auto& it : this->files) {
+        cur_file = it.second;
+        delete cur_file->path;
+        delete cur_file;
+    }
+    this->files.clear();
+
+    /* Set header fields. */
+    header->header_size = sizeof(*header);
+    header->file_hash_table_size = this->file_hash_table_size;
+    header->file_table_size = this->file_table_size;
+    header->dir_hash_table_size = this->dir_hash_table_size;
+    header->dir_table_size = this->dir_table_size;
+    header->file_partition_ofs = ROMFS_FILEPARTITION_OFS;
+    header->dir_hash_table_ofs =
+        (header->file_partition_ofs + this->file_partition_size + 3ULL) & ~3ULL;
+    header->dir_table_ofs = header->dir_hash_table_ofs + header->dir_hash_table_size;
+    header->file_hash_table_ofs = header->dir_table_ofs + header->dir_table_size;
+    header->file_table_ofs = header->file_hash_table_ofs + header->file_hash_table_size;
+
+    std::vector<u8> header_data(sizeof(RomFSHeader));
+    std::memcpy(header_data.data(), header, header_data.size());
+    out.emplace(0, std::make_shared<VectorVfsFile>(header_data));
+
+    std::vector<u8> meta_out(this->file_hash_table_size + this->file_table_size +
+                             this->dir_hash_table_size + this->dir_table_size);
+    std::memcpy(meta_out.data(), metadata, meta_out.size());
+    out.emplace(header->dir_hash_table_ofs, std::make_shared<VectorVfsFile>(meta_out));
+
+    return out;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/fsmitm_romfsbuild.hpp b/src/core/file_sys/fsmitm_romfsbuild.hpp
new file mode 100644
index 000000000..b897aab21
--- /dev/null
+++ b/src/core/file_sys/fsmitm_romfsbuild.hpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2018 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Adapted by DarkLordZach for use/interaction with yuzu
+ *
+ * Modifications Copyright 2018 yuzu emulator team
+ * Licensed under GPLv2 or any later version
+ * Refer to the license.txt file included.
+ */
+
+#pragma once
+#include <map>
+#include <boost/detail/container_fwd.hpp>
+#include "common/common_types.h"
+#include "vfs.h"
+
+namespace FileSys {
+
+/* Used as comparator for std::map<char *, RomFSBuild*Context> */
+struct build_ctx_cmp {
+    bool operator()(const char* a, const char* b) const {
+        return strcmp(a, b) < 0;
+    }
+};
+
+struct RomFSDirectoryEntry;
+struct RomFSFileEntry;
+struct RomFSBuildDirectoryContext;
+struct RomFSBuildFileContext;
+
+class RomFSBuildContext {
+private:
+    VirtualDir base;
+    RomFSBuildDirectoryContext* root;
+    std::map<char*, RomFSBuildDirectoryContext*, build_ctx_cmp> directories;
+    std::map<char*, RomFSBuildFileContext*, build_ctx_cmp> files;
+    u64 num_dirs = 0;
+    u64 num_files = 0;
+    u64 dir_table_size = 0;
+    u64 file_table_size = 0;
+    u64 dir_hash_table_size = 0;
+    u64 file_hash_table_size = 0;
+    u64 file_partition_size = 0;
+
+    void VisitDirectory(VirtualDir filesys, RomFSBuildDirectoryContext* parent);
+
+    bool AddDirectory(RomFSBuildDirectoryContext* parent_dir_ctx,
+                      RomFSBuildDirectoryContext* dir_ctx,
+                      RomFSBuildDirectoryContext** out_dir_ctx);
+    bool AddFile(RomFSBuildDirectoryContext* parent_dir_ctx, RomFSBuildFileContext* file_ctx);
+
+public:
+    explicit RomFSBuildContext(VirtualDir base);
+
+    /* This finalizes the context. */
+    std::map<u64, VirtualFile> Build();
+};
+
+static inline RomFSDirectoryEntry* romfs_get_direntry(void* directories, uint32_t offset) {
+    return (RomFSDirectoryEntry*)((uintptr_t)directories + offset);
+}
+
+static inline RomFSFileEntry* romfs_get_fentry(void* files, uint32_t offset) {
+    return (RomFSFileEntry*)((uintptr_t)files + offset);
+}
+
+static inline uint32_t romfs_calc_path_hash(uint32_t parent, const unsigned char* path,
+                                            uint32_t start, size_t path_len) {
+    uint32_t hash = parent ^ 123456789;
+    for (uint32_t i = 0; i < path_len; i++) {
+        hash = (hash >> 5) | (hash << 27);
+        hash ^= path[start + i];
+    }
+
+    return hash;
+}
+
+static inline uint32_t romfs_get_hash_table_count(uint32_t num_entries) {
+    if (num_entries < 3) {
+        return 3;
+    } else if (num_entries < 19) {
+        return num_entries | 1;
+    }
+    uint32_t count = num_entries;
+    while (count % 2 == 0 || count % 3 == 0 || count % 5 == 0 || count % 7 == 0 ||
+           count % 11 == 0 || count % 13 == 0 || count % 17 == 0) {
+        count++;
+    }
+    return count;
+}
+
+} // namespace FileSys