Function read_dentry_name

src/os/linux/dentry_path.cpp:14–39

Read a dentry's leaf name. Tries qstr.name (long names, kmalloc'd buffer) first; falls back to the inline shortname union (d_shortname/d_iname).

// Read a dentry's leaf name. Tries qstr.name (long names, kmalloc'd buffer)
// first; falls back to the inline shortname union (d_shortname/d_iname).
std::string read_dentry_name(const Engine& eng, VAddr dentry_va,
                              const DentryOffsets& d)
{
    if (dentry_va == 0) return {};

    u32 name_len = 0;
    VAddr name_ptr = 0;
    kva_read_pod(eng, dentry_va + d.d_name + d.qstr_len,  name_len);
    kva_read_pod(eng, dentry_va + d.d_name + d.qstr_name, name_ptr);

    if (name_len > 0 && name_len <= 255 && name_ptr != 0) {
        std::vector<char> buf(name_len + 1, 0);
        if (kva_read(eng, name_ptr, buf.data(), name_len))
            return std::string(buf.data(), name_len);
    }

    if (d.d_iname == 0) return {};
    constexpr std::size_t kInlineCap = 40;
    std::vector<char> in(kInlineCap, 0);
    if (kva_read(eng, dentry_va + d.d_iname, in.data(), kInlineCap)) {
        std::size_t n = 0;
        while (n < kInlineCap && in[n]) ++n;
        return std::string(in.data(), n);
    }
    return {};
}

} // anonymous