SandboxedFile.cpp

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// ======================================================================
// \title Os/SandboxedFile.cpp
// \brief Implementation of directory-sandboxed file wrapper
// ======================================================================
#include <Fw/Types/Assert.hpp>
#include <Fw/Types/StringUtils.hpp>
#include <Os/SandboxedFile.hpp>
#include <cstring>

namespace Os {

// Fail-closed: open() returns OUTSIDE_SANDBOX until configure() is called
SandboxedFile::SandboxedFile() : m_file(), m_allowedDirectory(""), m_configured(false) {}

SandboxedFile::~SandboxedFile() {
    if (m_file.isOpen()) {
        m_file.close();
    }
}

void SandboxedFile::configure(const char* allowedDirectory) {
    FW_ASSERT(allowedDirectory != nullptr);
    FW_ASSERT(!m_file.isOpen());

    // Resolve the allowed directory (relative paths resolve against CWD)
    char resolved[FilePathUtils::MAX_PATH_LENGTH];
    const FilePathUtils::Status resolveStatus =
        FilePathUtils::resolveFromCwd(allowedDirectory, resolved, sizeof(resolved));
    FW_ASSERT(resolveStatus == FilePathUtils::VALID);

    // Ensure trailing '/'
    const FwSizeType resolvedLen = Fw::StringUtils::string_length(resolved, FilePathUtils::MAX_PATH_LENGTH);
    FW_ASSERT(resolvedLen > 0);
    FW_ASSERT(resolvedLen + 2 <= FilePathUtils::MAX_PATH_LENGTH);
    if (resolved[resolvedLen - 1] != '/') {
        resolved[resolvedLen] = '/';
        resolved[resolvedLen + 1] = '\0';
    }

    m_allowedDirectory = resolved;
    m_configured = true;
}

bool SandboxedFile::isConfigured() const {
    return m_configured;
}

Os::FileInterface::Status SandboxedFile::open(const char* path,
                                              Os::FileInterface::Mode mode,
                                              Os::FileInterface::OverwriteType overwrite) {
    FW_ASSERT(path != nullptr);

    if (!m_configured) {
        return Os::FileInterface::Status::OUTSIDE_SANDBOX;
    }

    // Resolve path against CWD then check containment
    char resolvedPath[FilePathUtils::MAX_PATH_LENGTH];
    const FilePathUtils::Status resolveStatus = FilePathUtils::resolveFromCwd(path, resolvedPath, sizeof(resolvedPath));
    if (resolveStatus != FilePathUtils::VALID) {
        return Os::FileInterface::Status::OUTSIDE_SANDBOX;
    }

    if (FilePathUtils::checkContainment(resolvedPath, m_allowedDirectory.toChar()) != FilePathUtils::VALID) {
        return Os::FileInterface::Status::OUTSIDE_SANDBOX;
    }

    return m_file.open(resolvedPath, mode, overwrite);
}

void SandboxedFile::close() {
    m_file.close();
}

bool SandboxedFile::isOpen() const {
    return m_file.isOpen();
}

Os::FileInterface::Status SandboxedFile::size(FwSizeType& size_result) {
    return m_file.size(size_result);
}

Os::FileInterface::Status SandboxedFile::position(FwSizeType& position_result) {
    return m_file.position(position_result);
}

Os::FileInterface::Status SandboxedFile::preallocate(FwSizeType offset, FwSizeType length) {
    return m_file.preallocate(offset, length);
}

Os::FileInterface::Status SandboxedFile::seek(FwSignedSizeType offset, Os::FileInterface::SeekType seekType) {
    return m_file.seek(offset, seekType);
}

Os::FileInterface::Status SandboxedFile::flush() {
    return m_file.flush();
}

Os::FileInterface::Status SandboxedFile::read(U8* buffer, FwSizeType& size, Os::FileInterface::WaitType wait) {
    return m_file.read(buffer, size, wait);
}

Os::FileInterface::Status SandboxedFile::read(U8* buffer, FwSizeType& size) {
    return m_file.read(buffer, size);
}

Os::FileInterface::Status SandboxedFile::write(const U8* buffer, FwSizeType& size, Os::FileInterface::WaitType wait) {
    return m_file.write(buffer, size, wait);
}

Os::FileInterface::Status SandboxedFile::write(const U8* buffer, FwSizeType& size) {
    return m_file.write(buffer, size);
}

Os::FileInterface::Status SandboxedFile::calculateCrc(U32& crc) {
    return m_file.calculateCrc(crc);
}

const char* SandboxedFile::getSandboxDirectory() const {
    return m_allowedDirectory.toChar();
}

}  // namespace Os