Add process_get_module_path (#735)

crates/livesplit-auto-splitting/README.md

@@ -157,6 +157,23 @@ extern "C" {
         name_ptr: *const u8,
         name_len: usize,
     ) -> Option<NonZeroU64>;
+    /// Stores the file system path of a module in a process in the buffer
+    /// given. The pointer to the module name needs to point to valid UTF-8
+    /// encoded text with the given length. The path is a path that is
+    /// accessible through the WASI file system, so a Windows path of
+    /// `C:\foo\bar.exe` would be returned as `/mnt/c/foo/bar.exe`. Returns
+    /// `false` if the buffer is too small. After this call, no matter whether
+    /// it was successful or not, the `buf_len_ptr` will be set to the required
+    /// buffer size. If `false` is returned and the `buf_len_ptr` got set to 0,
+    /// the path or the module does not exist or it failed to get read. The path
+    /// is guaranteed to be valid UTF-8 and is not nul-terminated.
+    pub fn process_get_module_path(
+        process: Process,
+        name_ptr: *const u8,
+        name_len: usize,
+        buf_ptr: *mut u8,
+        buf_len_ptr: *mut usize,
+    ) -> bool;
     /// Stores the file system path of the executable in the buffer given. The
     /// path is a path that is accessible through the WASI file system, so a
     /// Windows path of `C:\foo\bar.exe` would be returned as

crates/livesplit-auto-splitting/src/lib.rs

@@ -157,6 +157,23 @@
 //!         name_ptr: *const u8,
 //!         name_len: usize,
 //!     ) -> Option<NonZeroU64>;
+//!     /// Stores the file system path of a module in a process in the buffer
+//!     /// given. The pointer to the module name needs to point to valid UTF-8
+//!     /// encoded text with the given length. The path is a path that is
+//!     /// accessible through the WASI file system, so a Windows path of
+//!     /// `C:\foo\bar.exe` would be returned as `/mnt/c/foo/bar.exe`. Returns
+//!     /// `false` if the buffer is too small. After this call, no matter whether
+//!     /// it was successful or not, the `buf_len_ptr` will be set to the required
+//!     /// buffer size. If `false` is returned and the `buf_len_ptr` got set to 0,
+//!     /// the path or the module does not exist or it failed to get read. The path
+//!     /// is guaranteed to be valid UTF-8 and is not nul-terminated.
+//!     pub fn process_get_module_path(
+//!         process: Process,
+//!         name_ptr: *const u8,
+//!         name_len: usize,
+//!         buf_ptr: *mut u8,
+//!         buf_len_ptr: *mut usize,
+//!     ) -> bool;
 //!     /// Stores the file system path of the executable in the buffer given. The
 //!     /// path is a path that is accessible through the WASI file system, so a
 //!     /// Windows path of `C:\foo\bar.exe` would be returned as

crates/livesplit-auto-splitting/src/process.rs

@@ -141,6 +141,15 @@ impl Process {
             .sum())
     }
 
+    pub(super) fn module_path(&mut self, module: &str) -> Result<Box<str>, ModuleError> {
+        self.refresh_memory_ranges()?;
+        self.memory_ranges
+            .iter()
+            .find(|m| m.filename().is_some_and(|f| f.ends_with(module)))
+            .context(ModuleDoesntExist)
+            .map(|m| build_path(m.filename().unwrap()).unwrap_or_default())
+    }
+
     pub(super) fn read_mem(&self, address: Address, buf: &mut [u8]) -> io::Result<()> {
         self.handle.copy_address(address as usize, buf)
     }

crates/livesplit-auto-splitting/src/runtime.rs

@@ -954,6 +954,41 @@ fn bind_interface<T: Timer>(linker: &mut Linker<Context<T>>) -> Result<(), Creat
             source,
             name: "process_get_path",
         })?
+        .func_wrap("env", "process_get_module_path", {
+            |mut caller: Caller<'_, Context<T>>,
+             process: u64,
+             name_ptr: u32,
+             name_len: u32,
+             path_ptr: u32,
+             path_len_ptr: u32| {
+                let (memory, context) = memory_and_context(&mut caller);
+                let module_name = get_str(memory, name_ptr, name_len)?;
+                let path = context
+                    .processes
+                    .get_mut(ProcessKey::from(KeyData::from_ffi(process)))
+                    .ok_or_else(|| format_err!("Invalid process handle: {process}"))?
+                    .module_path(module_name);
+
+                let path_len_bytes = get_arr_mut(memory, path_len_ptr)?;
+                if let Ok(path) = path {
+                    let path_len = u32::from_le_bytes(*path_len_bytes) as usize;
+                    *path_len_bytes = (path.len() as u32).to_le_bytes();
+                    if path_len < path.len() {
+                        return Ok(0u32);
+                    }
+                    let buf = get_slice_mut(memory, path_ptr, path.len() as _)?;
+                    buf.copy_from_slice(path.as_bytes());
+                    Ok(1u32)
+                } else {
+                    *path_len_bytes = 0u32.to_le_bytes();
+                    Ok(0u32)
+                }
+            }
+        })
+        .map_err(|source| CreationError::LinkFunction {
+            source,
+            name: "process_get_module_path",
+        })?
         .func_wrap("env", "process_read", {
             |mut caller: Caller<'_, Context<T>>,
              process: u64,

src/auto_splitting/mod.rs

@@ -157,6 +157,23 @@
 //!         name_ptr: *const u8,
 //!         name_len: usize,
 //!     ) -> Option<NonZeroU64>;
+//!     /// Stores the file system path of a module in a process in the buffer
+//!     /// given. The pointer to the module name needs to point to valid UTF-8
+//!     /// encoded text with the given length. The path is a path that is
+//!     /// accessible through the WASI file system, so a Windows path of
+//!     /// `C:\foo\bar.exe` would be returned as `/mnt/c/foo/bar.exe`. Returns
+//!     /// `false` if the buffer is too small. After this call, no matter whether
+//!     /// it was successful or not, the `buf_len_ptr` will be set to the required
+//!     /// buffer size. If `false` is returned and the `buf_len_ptr` got set to 0,
+//!     /// the path or the module does not exist or it failed to get read. The path
+//!     /// is guaranteed to be valid UTF-8 and is not nul-terminated.
+//!     pub fn process_get_module_path(
+//!         process: Process,
+//!         name_ptr: *const u8,
+//!         name_len: usize,
+//!         buf_ptr: *mut u8,
+//!         buf_len_ptr: *mut usize,
+//!     ) -> bool;
 //!     /// Stores the file system path of the executable in the buffer given. The
 //!     /// path is a path that is accessible through the WASI file system, so a
 //!     /// Windows path of `C:\foo\bar.exe` would be returned as