Function fs_readdir

host/sysenv/sys_fs.cpp:296–329

readdir(dir_fd:i32, entry_ptr) -> i32 Returns: 0 = entry written, 1 = end of directory, -errno = error.

// readdir(dir_fd:i32, entry_ptr) -> i32
// Returns: 0 = entry written, 1 = end of directory, -errno = error.
static std::vector<Value> fs_readdir(Stack& stack) {
    Frame& frame = stack.frames.top();
    i32_t dir_fd    = std::get<i32_t>(frame.locals[0]);
    i64_t entry_ptr = get_ptr(frame.locals[1]);
    FdEntry* e = fd_table.get(dir_fd);
    if(!e || !e->is_dir || !e->dir) return {Value(i32_t(-EBADF))};
    DirIter& di = *e->dir;
    if(di.it == di.end) return {Value(i32_t(1))};

    try {
        const fs::directory_entry& entry = *di.it;
        uint8_t buf[WASM_DIRENT_SIZE] = {};
        // std::filesystem doesn't expose a stable inode number cross-platform;
        // hash the path so each entry has a distinct, deterministic id.
        uint32_t ino  = (uint32_t)fs::hash_value(entry.path());
        uint8_t  type = dt_from_entry(entry);
        std::string name = entry.path().filename().string();
        std::memcpy(buf + 0, &ino,  4);
        std::memcpy(buf + 4, &type, 1);
        std::strncpy(reinterpret_cast<char*>(buf + 5), name.c_str(), 254);
        buf[5 + 254] = '\0';
        mem_write(stack, entry_ptr, buf, WASM_DIRENT_SIZE);

        std::error_code ec;
        di.it.increment(ec);
        if(ec) {
            errno = ec.value();
            return {Value(err_code())};
        }
        return {Value(i32_t(0))};
    } catch(...) {
        return {Value(i32_t(-EFAULT))};
    }
}

// closedir(dir_fd:i32) -> i32
static std::vector<Value> fs_closedir(Stack& stack) {