HLE/FS: Return the proper error codes on file Read/Write operations.

These operations are limited by the open flags specified while opening the file.

src/core/file_sys/disk_archive.cpp

@@ -124,17 +124,23 @@ bool DiskFile::Open() {
     return file->IsOpen();
 }
 
-size_t DiskFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+ResultVal<size_t> DiskFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+    if (!mode.read_flag && !mode.write_flag)
+        return ResultCode(ErrorDescription::FS_InvalidOpenFlags, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
+
     file->Seek(offset, SEEK_SET);
-    return file->ReadBytes(buffer, length);
+    return MakeResult<size_t>(file->ReadBytes(buffer, length));
 }
 
-size_t DiskFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+ResultVal<size_t> DiskFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+    if (!mode.write_flag)
+        return ResultCode(ErrorDescription::FS_InvalidOpenFlags, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
+
     file->Seek(offset, SEEK_SET);
     size_t written = file->WriteBytes(buffer, length);
     if (flush)
         file->Flush();
-    return written;
+    return MakeResult<size_t>(written);
 }
 
 u64 DiskFile::GetSize() const {

src/core/file_sys/disk_archive.h

@@ -55,8 +55,8 @@ public:
     DiskFile(const DiskArchive& archive, const Path& path, const Mode mode);
 
     bool Open() override;
-    size_t Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
-    size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;
     bool SetSize(u64 size) const override;
     bool Close() const override;

src/core/file_sys/file_backend.h

@@ -7,6 +7,7 @@
 #include <cstddef>
 
 #include "common/common_types.h"
+#include "core/hle/result.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // FileSys namespace
@@ -29,9 +30,9 @@ public:
      * @param offset Offset in bytes to start reading data from
      * @param length Length in bytes of data to read from file
      * @param buffer Buffer to read data into
-     * @return Number of bytes read
+     * @return Number of bytes read, or error code
      */
-    virtual size_t Read(u64 offset, size_t length, u8* buffer) const = 0;
+    virtual ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const = 0;
 
     /**
      * Write data to the file
@@ -39,9 +40,9 @@ public:
      * @param length Length in bytes of data to write to file
      * @param flush The flush parameters (0 == do not flush)
      * @param buffer Buffer to read data from
-     * @return Number of bytes written
+     * @return Number of bytes written, or error code
      */
-    virtual size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const = 0;
+    virtual ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const = 0;
 
     /**
      * Get the size of the file in bytes

src/core/file_sys/ivfc_archive.cpp

@@ -68,17 +68,18 @@ u64 IVFCArchive::GetFreeBytes() const {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-size_t IVFCFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+ResultVal<size_t> IVFCFile::Read(const u64 offset, const size_t length, u8* buffer) const {
     LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
     romfs_file->Seek(data_offset + offset, SEEK_SET);
     size_t read_length = (size_t)std::min((u64)length, data_size - offset);
 
-    return romfs_file->ReadBytes(buffer, read_length);
+    return MakeResult<size_t>(romfs_file->ReadBytes(buffer, read_length));
 }
 
-size_t IVFCFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+ResultVal<size_t> IVFCFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
     LOG_ERROR(Service_FS, "Attempted to write to IVFC file");
-    return 0;
+    // TODO(Subv): Find error code
+    return MakeResult<size_t>(0);
 }
 
 u64 IVFCFile::GetSize() const {

src/core/file_sys/ivfc_archive.h

@@ -56,8 +56,8 @@ public:
         : romfs_file(file), data_offset(offset), data_size(size) {}
 
     bool Open() override { return true; }
-    size_t Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
-    size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;
     bool SetSize(u64 size) const override;
     bool Close() const override { return false; }

src/core/hle/result.h

@@ -21,6 +21,7 @@ enum class ErrorDescription : u32 {
     WrongAddress = 53,
     FS_NotFound = 120,
     FS_AlreadyExists = 190,
+    FS_InvalidOpenFlags = 230,
     FS_NotAFile = 250,
     FS_NotFormatted = 340, ///< This is used by the FS service when creating a SaveData archive
     InvalidSection = 1000,

src/core/hle/service/fs/archive.cpp

@@ -103,7 +103,14 @@ ResultVal<bool> File::SyncRequest() {
             u32 address = cmd_buff[5];
             LOG_TRACE(Service_FS, "Read %s %s: offset=0x%llx length=%d address=0x%x",
                       GetTypeName().c_str(), GetName().c_str(), offset, length, address);
-            cmd_buff[2] = static_cast<u32>(backend->Read(offset, length, Memory::GetPointer(address)));
+            if (offset + length > backend->GetSize())
+                LOG_ERROR(Service_FS, "Reading from out of bounds offset=0x%llX length=0x%08X file_size=0x%llX", offset, length, backend->GetSize());
+            ResultVal<size_t> read = backend->Read(offset, length, Memory::GetPointer(address));
+            if (read.Failed()) {
+                cmd_buff[1] = read.Code().raw;
+                return read.Code();
+            }
+            cmd_buff[2] = static_cast<u32>(read.MoveFrom());
             break;
         }
 
@@ -116,7 +123,13 @@ ResultVal<bool> File::SyncRequest() {
             u32 address = cmd_buff[6];
             LOG_TRACE(Service_FS, "Write %s %s: offset=0x%llx length=%d address=0x%x, flush=0x%x",
                       GetTypeName().c_str(), GetName().c_str(), offset, length, address, flush);
-            cmd_buff[2] = static_cast<u32>(backend->Write(offset, length, flush != 0, Memory::GetPointer(address)));
+
+            ResultVal<size_t> written = backend->Write(offset, length, flush != 0, Memory::GetPointer(address));
+            if (written.Failed()) {
+                cmd_buff[1] = written.Code().raw;
+                return written.Code();
+            }
+            cmd_buff[2] = static_cast<u32>(written.MoveFrom());
             break;
         }