feat: add memory reader

src-tauri/src/lib.rs

@@ -7,6 +7,7 @@ use tauri_plugin_fs::FsExt;
 
 pub mod commands;
 pub mod config;
+pub mod memory_reader;
 pub mod osudb;
 pub mod presence;
 pub mod state;

src-tauri/src/memory_reader.rs

@@ -0,0 +1,519 @@
+//! osu_memory_reader.rs
+//!
+//! External, read-only memory reader for the osu! stable client, structured
+//! the same way community tools like tosu / gosumemory work:
+//!
+//!   1. Open the osu process with PROCESS_VM_READ.
+//!   2. Enumerate its committed memory regions.
+//!   3. Scan those regions for known byte-pattern "signatures".
+//!   4. Walk a short pointer chain from each signature to the real struct.
+//!   5. Parse out the fields you care about (username, mods, combo, etc).
+//!
+//! IMPORTANT: The actual signature bytes below are PLACEHOLDERS. osu!
+//! updates its binary regularly, which shifts/breaks raw byte signatures.
+//! Community tools maintain live, current signatures — pull up-to-date
+//! ones from tosu's open-source repo (github.com/KotRikD/tosu, see its
+//! `packages/tosu/src/memory/` signature definitions) and drop them into
+//! the `SIGNATURES` table below. This file gives you the engine; you keep
+//! the signature table current.
+//!
+//! This is entirely read-only (ReadProcessMemory only, never Write) and
+//! only targets your own launched osu! process — no injection involved.
+//!
+//! ---------------------------------------------------------------------
+//! Cargo.toml additions (on top of the ones from osu_scanner.rs):
+//!
+//! [dependencies]
+//! windows = { version = "0.58", features = [
+//!     "Win32_System_Diagnostics_ToolHelp",
+//!     "Win32_System_Memory",
+//!     "Win32_System_Threading",
+//!     "Win32_System_Diagnostics_Debug",
+//!     "Win32_Foundation"
+//! ] }
+//! ---------------------------------------------------------------------
+
+use serde::Serialize;
+use std::collections::HashMap;
+use windows::Win32::Foundation::{CloseHandle, HANDLE};
+use windows::Win32::System::Diagnostics::Debug::ReadProcessMemory;
+use windows::Win32::System::Memory::{
+    MEM_COMMIT, MEMORY_BASIC_INFORMATION, PAGE_GUARD, PAGE_NOACCESS, VirtualQueryEx,
+};
+use windows::Win32::System::Threading::{OpenProcess, PROCESS_QUERY_INFORMATION, PROCESS_VM_READ};
+
+// =========================================================================
+// Signature table — REPLACE with current values, see module doc comment.
+// =========================================================================
+
+/// A byte pattern to search for in process memory. `None` = wildcard byte.
+#[derive(Clone)]
+pub struct Signature {
+    pub name: &'static str,
+    pub pattern: &'static [Option<u8>],
+    /// Byte offset from the START of the matched pattern to the address
+    /// (or start of a pointer chain) you actually want to read.
+    pub offset: isize,
+}
+
+/// Helper macro so signatures can be written like Cheat Engine AOB strings,
+/// e.g. sig!("F8 01 74 04 ?? ?? ?? ??", offset = 5).
+macro_rules! sig {
+    ($bytes:expr) => {{ parse_aob($bytes) }};
+}
+
+fn parse_aob(s: &str) -> Vec<Option<u8>> {
+    s.split_whitespace()
+        .map(|tok| {
+            if tok == "??" || tok == "?" {
+                None
+            } else {
+                Some(u8::from_str_radix(tok, 16).expect("bad AOB byte"))
+            }
+        })
+        .collect()
+}
+
+/// NOTE: These are PLACEHOLDER patterns illustrating the *shape* tosu-style
+/// signatures take (short, somewhat unique byte runs with wildcards around
+/// the volatile parts). Do not expect these exact bytes to match a real
+/// osu! binary — swap them for current ones before using this for real.
+pub fn build_signature_table() -> HashMap<&'static str, Signature> {
+    let mut map = HashMap::new();
+
+    map.insert(
+        "username_ptr",
+        Signature {
+            name: "username_ptr",
+            pattern: Box::leak(sig!("75 04 33 C0 EB 0A A1 ?? ?? ?? ??").into_boxed_slice()),
+            offset: 7, // offset to the 4-byte address embedded in the instruction
+        },
+    );
+
+    map.insert(
+        "game_mode_ptr",
+        Signature {
+            name: "game_mode_ptr",
+            pattern: Box::leak(sig!("83 F8 08 7D 05 ?? ?? ?? ?? ??").into_boxed_slice()),
+            offset: 5,
+        },
+    );
+
+    map.insert(
+        "current_beatmap_ptr",
+        Signature {
+            name: "current_beatmap_ptr",
+            pattern: Box::leak(sig!("6A 01 6A 00 A1 ?? ?? ?? ?? 8B 00").into_boxed_slice()),
+            offset: 4,
+        },
+    );
+
+    map.insert(
+        "combo_ptr",
+        Signature {
+            name: "combo_ptr",
+            pattern: Box::leak(
+                sig!("83 3D ?? ?? ?? ?? 00 7E 34 A1 ?? ?? ?? ??").into_boxed_slice(),
+            ),
+            offset: 9,
+        },
+    );
+
+    // userId typically lives on the same "player info" object as username,
+    // just at a different field offset — but tosu-style tools usually give
+    // it its own independent signature since it's read even when the
+    // username string hasn't been touched yet (e.g. right after login).
+    map.insert(
+        "user_id_ptr",
+        Signature {
+            name: "user_id_ptr",
+            pattern: Box::leak(sig!("A1 ?? ?? ?? ?? 89 45 ?? 8B 45 ?? 8B 0D").into_boxed_slice()),
+            offset: 1,
+        },
+    );
+
+    map
+}
+
+// =========================================================================
+// Process handle + raw memory access
+// =========================================================================
+
+pub struct MemoryReader {
+    handle: HANDLE,
+    pid: u32,
+    /// Cached list of readable committed memory regions.
+    regions: Vec<(usize, usize)>, // (base_address, size)
+}
+
+impl MemoryReader {
+    /// Opens the given PID for reading. Returns None if the process can't
+    /// be opened (e.g. insufficient privileges, process exited).
+    pub fn open(pid: u32) -> Option<Self> {
+        let handle =
+            unsafe { OpenProcess(PROCESS_VM_READ | PROCESS_QUERY_INFORMATION, false, pid).ok()? };
+        Some(Self {
+            handle,
+            pid,
+            regions: Vec::new(),
+        })
+    }
+
+    /// Re-enumerates committed, readable memory regions. Call once after
+    /// open() and periodically after (e.g. once per scan cycle), since the
+    /// process's memory layout can change.
+    pub fn refresh_regions(&mut self) {
+        self.regions.clear();
+        let mut address: usize = 0;
+
+        loop {
+            let mut mbi = MEMORY_BASIC_INFORMATION::default();
+            let result = unsafe {
+                VirtualQueryEx(
+                    self.handle,
+                    Some(address as *const _),
+                    &mut mbi,
+                    std::mem::size_of::<MEMORY_BASIC_INFORMATION>(),
+                )
+            };
+
+            if result == 0 {
+                break; // no more regions
+            }
+
+            let region_size = mbi.RegionSize;
+            let is_committed = mbi.State == MEM_COMMIT;
+            let is_guarded = (mbi.Protect & PAGE_GUARD).0 != 0;
+            let is_no_access = mbi.Protect == PAGE_NOACCESS;
+
+            if is_committed && !is_guarded && !is_no_access && region_size > 0 {
+                self.regions.push((mbi.BaseAddress as usize, region_size));
+            }
+
+            address = (mbi.BaseAddress as usize).saturating_add(region_size);
+            if address == 0 {
+                break;
+            }
+        }
+    }
+
+    /// Reads `size` bytes starting at `address`. Returns None on failure
+    /// (unmapped page, access denied, process exited mid-read, etc).
+    pub fn read_bytes(&self, address: usize, size: usize) -> Option<Vec<u8>> {
+        let mut buffer = vec![0u8; size];
+        let mut bytes_read = 0usize;
+
+        unsafe {
+            ReadProcessMemory(
+                self.handle,
+                address as *const _,
+                buffer.as_mut_ptr() as *mut _,
+                size,
+                Some(&mut bytes_read),
+            )
+            .ok()?;
+        }
+
+        buffer.truncate(bytes_read);
+        if buffer.is_empty() {
+            None
+        } else {
+            Some(buffer)
+        }
+    }
+
+    pub fn read_i32(&self, address: usize) -> Option<i32> {
+        let bytes = self.read_bytes(address, 4)?;
+        Some(i32::from_le_bytes(bytes.try_into().ok()?))
+    }
+
+    pub fn read_u32(&self, address: usize) -> Option<u32> {
+        let bytes = self.read_bytes(address, 4)?;
+        Some(u32::from_le_bytes(bytes.try_into().ok()?))
+    }
+
+    pub fn read_u16(&self, address: usize) -> Option<u16> {
+        let bytes = self.read_bytes(address, 2)?;
+        Some(u16::from_le_bytes(bytes.try_into().ok()?))
+    }
+
+    pub fn read_f64(&self, address: usize) -> Option<f64> {
+        let bytes = self.read_bytes(address, 8)?;
+        Some(f64::from_le_bytes(bytes.try_into().ok()?))
+    }
+
+    /// Reads a pointer-sized value (4 bytes for the 32-bit osu! stable
+    /// client). Change to 8 bytes if you ever target a 64-bit build.
+    pub fn read_ptr(&self, address: usize) -> Option<usize> {
+        self.read_u32(address).map(|v| v as usize)
+    }
+
+    /// Reads a .NET-style string: [object header][length: i32][utf16 chars].
+    /// `base` should point at the object header; the classic offset for
+    /// .NET string length is +0x4 and chars start at +0x8, but verify
+    /// against your target since layouts can differ.
+    pub fn read_dotnet_string(&self, base: usize, max_len: usize) -> Option<String> {
+        let len = self.read_i32(base + 0x4)? as usize;
+        let len = len.min(max_len);
+        if len == 0 {
+            return Some(String::new());
+        }
+
+        let bytes = self.read_bytes(base + 0x8, len * 2)?;
+        let utf16: Vec<u16> = bytes
+            .chunks_exact(2)
+            .map(|b| u16::from_le_bytes([b[0], b[1]]))
+            .collect();
+
+        String::from_utf16(&utf16).ok()
+    }
+
+    /// Scans all cached regions for `signature.pattern`, returning the
+    /// absolute address where the pattern begins (before applying offset).
+    pub fn find_signature(&self, signature: &Signature) -> Option<usize> {
+        for &(base, size) in &self.regions {
+            // Read in chunks to avoid gigantic single allocations on huge
+            // regions; 1MB chunks with overlap so patterns aren't missed
+            // across a chunk boundary.
+            const CHUNK: usize = 1 << 20;
+            let overlap = signature.pattern.len().saturating_sub(1);
+            let mut offset = 0;
+
+            while offset < size {
+                let read_size = CHUNK.min(size - offset);
+                let Some(mem) = self.read_bytes(base + offset, read_size) else {
+                    offset += CHUNK;
+                    continue;
+                };
+
+                if let Some(pos) = find_pattern(&mem, signature.pattern) {
+                    return Some(base + offset + pos);
+                }
+
+                offset += CHUNK.saturating_sub(overlap).max(1);
+            }
+        }
+        None
+    }
+
+    pub fn pid(&self) -> u32 {
+        self.pid
+    }
+}
+
+impl Drop for MemoryReader {
+    fn drop(&mut self) {
+        unsafe {
+            let _ = CloseHandle(self.handle);
+        }
+    }
+}
+
+/// Naive substring search over a byte pattern with wildcards. Fine for
+/// per-scan-cycle use; swap for a Boyer-Moore-style skip table if you need
+/// to scan very large regions many times per second.
+fn find_pattern(haystack: &[u8], pattern: &[Option<u8>]) -> Option<usize> {
+    if pattern.is_empty() || haystack.len() < pattern.len() {
+        return None;
+    }
+
+    haystack.windows(pattern.len()).position(|window| {
+        window
+            .iter()
+            .zip(pattern.iter())
+            .all(|(b, p)| p.map_or(true, |expected| *b == expected))
+    })
+}
+
+// =========================================================================
+// High-level "osu state" reader
+// =========================================================================
+
+#[derive(Serialize, Debug, Default, Clone)]
+pub struct OsuState {
+    pub username: Option<String>,
+    pub user_id: Option<i32>,
+    pub game_mode: Option<i32>,
+    pub combo: Option<i32>,
+    pub beatmap_id: Option<i32>,
+}
+
+pub struct OsuMemoryClient {
+    reader: MemoryReader,
+    signatures: HashMap<&'static str, Signature>,
+    /// Cached resolved addresses so we don't re-scan the whole memory space
+    /// every single read — only re-resolve if a read at the cached address
+    /// stops making sense (e.g. after an osu update / restart).
+    resolved: HashMap<&'static str, usize>,
+    /// When true, prints signature resolution + read results to stderr.
+    /// Toggle via `new_with_debug`, or flip at runtime with `set_debug`.
+    debug: bool,
+}
+
+impl OsuMemoryClient {
+    pub fn new(pid: u32) -> Option<Self> {
+        Self::new_with_debug(pid, false)
+    }
+
+    /// Same as `new`, but with debug logging to stderr enabled/disabled
+    /// explicitly. Handy to wire up to a `--debug` CLI flag or a Tauri
+    /// dev-mode check (`cfg!(debug_assertions)`).
+    pub fn new_with_debug(pid: u32, debug: bool) -> Option<Self> {
+        let mut reader = MemoryReader::open(pid)?;
+        if debug {
+            eprintln!("[osu_memory] opening pid {pid} for reading");
+        }
+        reader.refresh_regions();
+        if debug {
+            eprintln!(
+                "[osu_memory] found {} readable regions",
+                reader.regions.len()
+            );
+        }
+        Some(Self {
+            reader,
+            signatures: build_signature_table(),
+            resolved: HashMap::new(),
+            debug,
+        })
+    }
+
+    pub fn set_debug(&mut self, debug: bool) {
+        self.debug = debug;
+    }
+
+    /// Call periodically (e.g. every few seconds, or whenever osu restarts)
+    /// to pick up new memory layout / re-find signatures.
+    pub fn refresh(&mut self) {
+        if self.debug {
+            eprintln!(
+                "[osu_memory] refreshing regions + clearing {} cached signature(s)",
+                self.resolved.len()
+            );
+        }
+        self.reader.refresh_regions();
+        self.resolved.clear();
+        if self.debug {
+            eprintln!(
+                "[osu_memory] {} readable regions after refresh",
+                self.reader.regions.len()
+            );
+        }
+    }
+
+    fn resolve(&mut self, key: &'static str) -> Option<usize> {
+        if let Some(addr) = self.resolved.get(key) {
+            if self.debug {
+                eprintln!("[osu_memory] {key} -> 0x{addr:X} (cached)");
+            }
+            return Some(*addr);
+        }
+
+        let sig = self.signatures.get(key)?.clone();
+        let Some(found) = self.reader.find_signature(&sig) else {
+            if self.debug {
+                eprintln!("[osu_memory] {key}: signature NOT FOUND in any scanned region");
+            }
+            return None;
+        };
+        let target = (found as isize + sig.offset) as usize;
+
+        if self.debug {
+            eprintln!(
+                "[osu_memory] {key}: signature matched at 0x{found:X}, target (offset {}) -> 0x{target:X}",
+                sig.offset
+            );
+        }
+
+        self.resolved.insert(key, target);
+        Some(target)
+    }
+
+    pub fn read_username(&mut self) -> Option<String> {
+        let addr = self.resolve("username_ptr")?;
+        let ptr = self.reader.read_ptr(addr)?;
+        let value = self.reader.read_dotnet_string(ptr, 64);
+        if self.debug {
+            eprintln!("[osu_memory] username -> {value:?}");
+        }
+        value
+    }
+
+    pub fn read_user_id(&mut self) -> Option<i32> {
+        let addr = self.resolve("user_id_ptr")?;
+        // Unlike username/combo/beatmap, this signature usually points
+        // straight at a static int slot rather than through an extra
+        // object pointer — verify against whatever real signature you use,
+        // some variants do need an extra self.reader.read_ptr() hop first.
+        let value = self.reader.read_i32(addr);
+        if self.debug {
+            eprintln!("[osu_memory] user_id -> {value:?}");
+        }
+        value
+    }
+
+    pub fn read_game_mode(&mut self) -> Option<i32> {
+        let addr = self.resolve("game_mode_ptr")?;
+        let ptr = self.reader.read_ptr(addr)?;
+        let value = self.reader.read_i32(ptr);
+        if self.debug {
+            eprintln!("[osu_memory] game_mode -> {value:?}");
+        }
+        value
+    }
+
+    pub fn read_combo(&mut self) -> Option<i32> {
+        let addr = self.resolve("combo_ptr")?;
+        let ptr = self.reader.read_ptr(addr)?;
+        let value = self.reader.read_i32(ptr);
+        if self.debug {
+            eprintln!("[osu_memory] combo -> {value:?}");
+        }
+        value
+    }
+
+    pub fn read_beatmap_id(&mut self) -> Option<i32> {
+        let addr = self.resolve("current_beatmap_ptr")?;
+        let ptr = self.reader.read_ptr(addr)?;
+        let value = self.reader.read_i32(ptr + 0xC); // example nested offset into the beatmap struct
+        if self.debug {
+            eprintln!("[osu_memory] beatmap_id -> {value:?}");
+        }
+        value
+    }
+
+    /// Convenience: read everything at once into a single struct, suitable
+    /// for bundling into your existing scan payload / emitting to the
+    /// frontend.
+    pub fn read_state(&mut self) -> OsuState {
+        if self.debug {
+            eprintln!(
+                "[osu_memory] --- reading full state (pid {}) ---",
+                self.reader.pid()
+            );
+        }
+        let state = OsuState {
+            username: self.read_username(),
+            user_id: self.read_user_id(),
+            game_mode: self.read_game_mode(),
+            combo: self.read_combo(),
+            beatmap_id: self.read_beatmap_id(),
+        };
+        if self.debug {
+            eprintln!("[osu_memory] state = {state:?}");
+        }
+        state
+    }
+}
+
+// =========================================================================
+// Example wiring into your existing watcher loop
+// =========================================================================
+//
+// let mut mem_client = OsuMemoryClient::new(osu_pid)?;
+// loop {
+//     let state = mem_client.read_state();
+//     // attach `state` to your ScanPayload before POSTing to the server
+//     // if a read silently comes back all-None a few cycles in a row,
+//     // call mem_client.refresh() in case osu updated/restarted.
+// }