Core: Simulate write-only file access with read-write access

src/common/io_file.cpp

@@ -40,28 +40,30 @@ namespace {
         switch (mode) {
         case FileAccessMode::Read:
             return L"rb";
-        case FileAccessMode::Write:
-            return L"wb";
         case FileAccessMode::Append:
             return L"ab";
+        case FileAccessMode::Write:
         case FileAccessMode::ReadWrite:
             return L"r+b";
         case FileAccessMode::ReadAppend:
             return L"a+b";
+        case FileAccessMode::Create:
+            return L"wb";
         }
         break;
     case FileType::TextFile:
         switch (mode) {
         case FileAccessMode::Read:
             return L"r";
-        case FileAccessMode::Write:
-            return L"w";
         case FileAccessMode::Append:
             return L"a";
+        case FileAccessMode::Write:
         case FileAccessMode::ReadWrite:
             return L"r+";
         case FileAccessMode::ReadAppend:
             return L"a+";
+        case FileAccessMode::Create:
+            return L"w";
         }
         break;
     }
@@ -91,28 +93,30 @@ namespace {
         switch (mode) {
         case FileAccessMode::Read:
             return "rb";
-        case FileAccessMode::Write:
-            return "wb";
         case FileAccessMode::Append:
             return "ab";
+        case FileAccessMode::Write:
         case FileAccessMode::ReadWrite:
             return "r+b";
         case FileAccessMode::ReadAppend:
             return "a+b";
+        case FileAccessMode::Create:
+            return "wb";
         }
         break;
     case FileType::TextFile:
         switch (mode) {
         case FileAccessMode::Read:
             return "r";
-        case FileAccessMode::Write:
-            return "w";
         case FileAccessMode::Append:
             return "a";
+        case FileAccessMode::Write:
         case FileAccessMode::ReadWrite:
             return "r+";
         case FileAccessMode::ReadAppend:
             return "a+";
+        case FileAccessMode::Create:
+            return "w";
         }
         break;
     }

src/common/io_file.h

@@ -21,9 +21,8 @@ enum class FileAccessMode {
      */
     Read = 1 << 0,
     /**
-     * If the file at path exists, the existing contents of the file are erased.
-     * The empty file is then opened for writing.
-     * If the file at path does not exist, it creates and opens a new empty file for writing.
+     * If the file at path exists, it opens the file for writing.
+     * If the file at path does not exist, it fails to open the file.
      */
     Write = 1 << 1,
     /**
@@ -42,6 +41,12 @@ enum class FileAccessMode {
      * reading and appending.
      */
     ReadAppend = Read | Append,
+    /**
+     * If the file at path exists, the existing contents of the file are erased.
+     * The empty file is then opened for writing.
+     * If the file at path does not exist, it creates and opens a new empty file for writing.
+     */
+    Create = 1 << 3,
 };
 DECLARE_ENUM_FLAG_OPERATORS(FileAccessMode);
 
@@ -102,6 +107,11 @@ class IOFile final {
         return file != nullptr;
     }
 
+    bool IsWriteOnly() const {
+        return file_access_mode == FileAccessMode::Append ||
+               file_access_mode == FileAccessMode::Write;
+    }
+
     uintptr_t GetFileMapping();
 
     int Open(const std::filesystem::path& path, FileAccessMode mode,
@@ -210,7 +220,7 @@ class IOFile final {
     }
 
     static size_t WriteBytes(const std::filesystem::path path, const auto& data) {
-        IOFile out(path, FileAccessMode::Write);
+        IOFile out(path, FileAccessMode::Create);
         return out.Write(data);
     }
 

src/common/logging/backend.cpp

@@ -62,7 +62,7 @@ class ColorConsoleBackend {
 class FileBackend {
 public:
     explicit FileBackend(const std::filesystem::path& filename)
-        : file{filename, FS::FileAccessMode::Write, FS::FileType::TextFile} {}
+        : file{filename, FS::FileAccessMode::Create, FS::FileType::TextFile} {}
 
     ~FileBackend() = default;
 

src/core/devtools/widget/common.h

@@ -152,7 +152,7 @@ inline std::string RunDisassembler(const std::string& disassembler_cli, const T&
             }
         } else {
             cli.replace(pos, src_arg.size(), "\"" + bin_path.string() + "\"");
-            Common::FS::IOFile file(bin_path, Common::FS::FileAccessMode::Write);
+            Common::FS::IOFile file(bin_path, Common::FS::FileAccessMode::Create);
             file.Write(shader_code);
             file.Close();
 

src/core/devtools/widget/frame_dump.cpp

@@ -122,7 +122,7 @@ void FrameDumpViewer::Draw() {
             const auto fname = fmt::format("{:%F %H-%M-%S} {}_{}_{}.bin", now_time,
                                            magic_enum::enum_name(selected_queue_type),
                                            selected_submit_num, selected_queue_num2);
-            Common::FS::IOFile file(fname, Common::FS::FileAccessMode::Write);
+            Common::FS::IOFile file(fname, Common::FS::FileAccessMode::Create);
             const auto& data = frame_dump->queues[selected_cmd].data;
             if (file.IsOpen()) {
                 DebugState.ShowDebugMessage(fmt::format("Dumping cmd as {}", fname));

src/core/file_format/psf.cpp

@@ -99,7 +99,7 @@ bool PSF::Open(const std::vector<u8>& psf_buffer) {
 }
 
 bool PSF::Encode(const std::filesystem::path& filepath) const {
-    Common::FS::IOFile file(filepath, Common::FS::FileAccessMode::Write);
+    Common::FS::IOFile file(filepath, Common::FS::FileAccessMode::Create);
     if (!file.IsOpen()) {
         return false;
     }

src/core/libraries/kernel/file_system.cpp

@@ -127,7 +127,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
                 return -1;
             }
             // Create a file if it doesn't exist
-            Common::FS::IOFile out(file->m_host_name, Common::FS::FileAccessMode::Write);
+            Common::FS::IOFile out(file->m_host_name, Common::FS::FileAccessMode::Create);
         }
     } else if (!exists) {
         // If we're not creating a file, and it doesn't exist, return ENOENT
@@ -202,22 +202,30 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
         }
 
         if (read) {
-            // Read only
+            // Open exclusively for reading
             e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::Read);
         } else if (read_only) {
             // Can't open files with write/read-write access in a read only directory
             h->DeleteHandle(handle);
             *__Error() = POSIX_EROFS;
             return -1;
-        } else if (append) {
-            // Append can be specified with rdwr or write, but we treat it as a separate mode.
-            e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::Append);
         } else if (write) {
-            // Write only
-            e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::Write);
+            if (append) {
+                // Open exclusively for appending
+                e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::Append);
+            } else {
+                // Open exclusively for writing
+                e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::Write);
+            }
         } else if (rdwr) {
             // Read and write
-            e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::ReadWrite);
+            if (append) {
+                // Open for reading and appending
+                e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::ReadAppend);
+            } else {
+                // Open for reading and writing
+                e = file->f.Open(file->m_host_name, Common::FS::FileAccessMode::ReadWrite);
+            }
         }
     }
 
@@ -348,6 +356,12 @@ size_t PS4_SYSV_ABI readv(s32 fd, const SceKernelIovec* iov, s32 iovcnt) {
         }
         return result;
     }
+
+    if (file->f.IsWriteOnly()) {
+        *__Error() = POSIX_EBADF;
+        return -1;
+    }
+
     size_t total_read = 0;
     for (s32 i = 0; i < iovcnt; i++) {
         total_read += ReadFile(file->f, iov[i].iov_base, iov[i].iov_len);
@@ -493,6 +507,12 @@ s64 PS4_SYSV_ABI read(s32 fd, void* buf, size_t nbytes) {
         }
         return result;
     }
+
+    if (file->f.IsWriteOnly()) {
+        *__Error() = POSIX_EBADF;
+        return -1;
+    }
+
     return ReadFile(file->f, buf, nbytes);
 }
 
@@ -784,11 +804,7 @@ s32 PS4_SYSV_ABI posix_rename(const char* from, const char* to) {
     auto* h = Common::Singleton<Core::FileSys::HandleTable>::Instance();
     auto file = h->GetFile(src_path);
     if (file) {
-        // We need to force ReadWrite if the file had Write access before
-        // Otherwise f.Open will clear the file contents.
-        auto access_mode = file->f.GetAccessMode() == Common::FS::FileAccessMode::Write
-                               ? Common::FS::FileAccessMode::ReadWrite
-                               : file->f.GetAccessMode();
+        auto access_mode = file->f.GetAccessMode();
         file->f.Close();
         std::filesystem::remove(src_path);
         file->f.Open(dst_path, access_mode);
@@ -831,6 +847,11 @@ s64 PS4_SYSV_ABI posix_preadv(s32 fd, SceKernelIovec* iov, s32 iovcnt, s64 offse
         return result;
     }
 
+    if (file->f.IsWriteOnly()) {
+        *__Error() = POSIX_EBADF;
+        return -1;
+    }
+
     const s64 pos = file->f.Tell();
     SCOPE_EXIT {
         file->f.Seek(pos);

src/core/libraries/save_data/save_instance.cpp

@@ -180,7 +180,7 @@ void SaveInstance::SetupAndMount(bool read_only, bool copy_icon, bool ignore_cor
     }
 
     if (!ignore_corrupt && !read_only) {
-        Common::FS::IOFile f(corrupt_file_path, Common::FS::FileAccessMode::Write);
+        Common::FS::IOFile f(corrupt_file_path, Common::FS::FileAccessMode::Create);
         f.Close();
     }
 

src/core/libraries/save_data/save_memory.cpp

@@ -59,7 +59,7 @@ void PersistMemory(u32 slot_id, bool lock) {
     while (n++ < 10) {
         try {
             IOFile f;
-            int r = f.Open(memoryPath, Common::FS::FileAccessMode::Write);
+            int r = f.Open(memoryPath, Common::FS::FileAccessMode::Create);
             if (f.IsOpen()) {
                 f.WriteRaw<u8>(data.memory_cache.data(), data.memory_cache.size());
                 f.Close();
@@ -148,7 +148,7 @@ void SetIcon(u32 slot_id, void* buf, size_t buf_size) {
             fs::copy_file(src_icon, icon_path);
         }
     } else {
-        IOFile file(icon_path, Common::FS::FileAccessMode::Write);
+        IOFile file(icon_path, Common::FS::FileAccessMode::Create);
         file.WriteRaw<u8>(buf, buf_size);
         file.Close();
     }

src/core/libraries/save_data/savedata.cpp

@@ -1389,7 +1389,7 @@ Error PS4_SYSV_ABI sceSaveDataSaveIcon(const OrbisSaveDataMountPoint* mountPoint
     }
 
     try {
-        const Common::FS::IOFile file(path, Common::FS::FileAccessMode::Write);
+        const Common::FS::IOFile file(path, Common::FS::FileAccessMode::Create);
         file.WriteRaw<u8>(icon->buf, std::min(icon->bufSize, icon->dataSize));
     } catch (const fs::filesystem_error& e) {
         LOG_ERROR(Lib_SaveData, "Failed to load icon: {}", e.what());

src/core/loader/elf.cpp

@@ -502,27 +502,27 @@ bool Elf::IsSharedLib() {
 }
 
 void Elf::ElfHeaderDebugDump(const std::filesystem::path& file_name) {
-    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Write,
+    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Create,
                          Common::FS::FileType::TextFile};
     f.WriteString(ElfHeaderStr());
 }
 
 void Elf::SelfHeaderDebugDump(const std::filesystem::path& file_name) {
-    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Write,
+    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Create,
                          Common::FS::FileType::TextFile};
     f.WriteString(SElfHeaderStr());
 }
 
 void Elf::SelfSegHeaderDebugDump(const std::filesystem::path& file_name) {
-    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Write,
+    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Create,
                          Common::FS::FileType::TextFile};
     for (u16 i = 0; i < m_self.segment_count; i++) {
         f.WriteString(SELFSegHeader(i));
     }
 }
 
 void Elf::PHeaderDebugDump(const std::filesystem::path& file_name) {
-    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Write,
+    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Create,
                          Common::FS::FileType::TextFile};
     if (m_elf_header.e_phentsize > 0) {
         for (u16 i = 0; i < m_elf_header.e_phnum; i++) {

src/core/loader/symbols_resolver.cpp

@@ -32,7 +32,7 @@ const SymbolRecord* SymbolsResolver::FindSymbol(const SymbolResolver& s) const {
 }
 
 void SymbolsResolver::DebugDump(const std::filesystem::path& file_name) {
-    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Write,
+    Common::FS::IOFile f{file_name, Common::FS::FileAccessMode::Create,
                          Common::FS::FileType::TextFile};
     for (const auto& symbol : m_symbols) {
         const auto ids = Common::SplitString(symbol.name, '#');

src/shader_recompiler/frontend/translate/translate.cpp

@@ -544,7 +544,7 @@ void Translator::EmitFetch(const GcnInst& inst) {
             std::filesystem::create_directories(dump_dir);
         }
         const auto filename = fmt::format("vs_{:#018x}.fetch.bin", info.pgm_hash);
-        const auto file = IOFile{dump_dir / filename, FileAccessMode::Write};
+        const auto file = IOFile{dump_dir / filename, FileAccessMode::Create};
         file.WriteRaw<u8>(fetch_data->code, fetch_data->size);
     }
 

src/shader_recompiler/ir/passes/flatten_extended_userdata_pass.cpp

@@ -39,7 +39,7 @@ static void DumpSrtProgram(const Shader::Info& info, const u8* code, size_t code
         std::filesystem::create_directories(dump_dir);
     }
     const auto filename = fmt::format("{}_{:#018x}.srtprogram.txt", info.stage, info.pgm_hash);
-    const auto file = IOFile{dump_dir / filename, FileAccessMode::Write, FileType::TextFile};
+    const auto file = IOFile{dump_dir / filename, FileAccessMode::Create, FileType::TextFile};
 
     u64 address = reinterpret_cast<u64>(code);
     u64 code_end = address + codesize;

src/shader_recompiler/ir/program.cpp

@@ -28,7 +28,7 @@ void DumpProgram(const Program& program, const Info& info, const std::string& ty
     }
     const auto ir_filename =
         fmt::format("{}_{:#018x}.{}irprogram.txt", info.stage, info.pgm_hash, type);
-    const auto ir_file = IOFile{dump_dir / ir_filename, FileAccessMode::Write, FileType::TextFile};
+    const auto ir_file = IOFile{dump_dir / ir_filename, FileAccessMode::Create, FileType::TextFile};
 
     size_t index{0};
     std::map<const IR::Inst*, size_t> inst_to_index;
@@ -46,7 +46,7 @@ void DumpProgram(const Program& program, const Info& info, const std::string& ty
 
     const auto asl_filename = fmt::format("{}_{:#018x}.{}asl.txt", info.stage, info.pgm_hash, type);
     const auto asl_file =
-        IOFile{dump_dir / asl_filename, FileAccessMode::Write, FileType::TextFile};
+        IOFile{dump_dir / asl_filename, FileAccessMode::Create, FileType::TextFile};
 
     for (const auto& node : program.syntax_list) {
         std::string s = IR::DumpASLNode(node, block_to_index, inst_to_index) + '\n';

src/video_core/renderer_vulkan/vk_pipeline_cache.cpp

@@ -611,7 +611,7 @@ void PipelineCache::DumpShader(std::span<const u32> code, u64 hash, Shader::Stag
         std::filesystem::create_directories(dump_dir);
     }
     const auto filename = fmt::format("{}.{}", GetShaderName(stage, hash, perm_idx), ext);
-    const auto file = IOFile{dump_dir / filename, FileAccessMode::Write};
+    const auto file = IOFile{dump_dir / filename, FileAccessMode::Create};
     file.WriteSpan(code);
 }