feat: add ability to dump extism kernel memory and generate coredumps, cleanup kernel memory layout (#539)

Fixes https://github.com/extism/extism/issues/537

- Requires wasmtime 14.0.0 or greater for coredump serialization
- Adds `EXTISM_COREDUMP` environment variable to write wasmtime coredump
to a file when an error occurs
- This will create a coredump from the main wasm module, which means it
doesn't give us too much insight into the kernel
- Adds `EXTISM_MEMDUMP` environment variable to write extism linear
memory to a file when an error occurs
  - This gives us access to the kernel memory  
- Adds some missing profiling options
- Converts timeouts to a Trap instead of a plain error, this helps us
get better information about where the timeout occured
- Some small improvements to error handling after a plugin call
- Adds a test for coredump and memdump generation
- Adds the ability to configure debug options using `PluginBuilder`
- Fixes memory layout and a wasted page of memory in the kernel, found
while debugging a memory dump

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: zshipko <zshipko@users.noreply.github.com>

kernel/src/lib.rs

@@ -17,13 +17,13 @@
 //! ## Input/Output
 //!
 //! Input and output are just allocated blocks of memory that are marked as either input or output using
-//! the `extism_input_set` or `extism_output_set` functions. The global variables `INPUT_OFFSET` contains
-//! the offset in memory to the input data and `INPUT_LENGTH` contains the size of the input data. `OUTPUT_OFFSET`
-//! and `OUTPUT_LENGTH` are used for the output data.
+//! the `extism_input_set` or `extism_output_set` functions. The MemoryRoot field `input_offset` contains
+//! the offset in memory to the input data and `input_length` contains the size of the input data. `output_offset`
+//! and `output_length` are used for the output data.
 //!
 //! ## Error handling
 //!
-//! The `ERROR` global is used to track the current error message. If it is set to `0` then there is no error.
+//! The `error` field is used to track the current error message. If it is set to `0` then there is no error.
 //! The length of the error message can be retreived using `extism_length`.
 //!
 //! ## Memory offsets
@@ -45,31 +45,6 @@ pub type Length = u64;
 /// WebAssembly page size
 const PAGE_SIZE: usize = 65536;
 
-/// Determines the amount of bytes that can be wasted by re-using a block. If more than this number is wasted by re-using
-/// a block then it will be split into two smaller blocks.
-const BLOCK_SPLIT_SIZE: usize = 128;
-
-/// Offset to the input data
-static mut INPUT_OFFSET: Pointer = 0;
-
-/// Length of the input data
-static mut INPUT_LENGTH: Length = 0;
-
-/// Offset to the output data
-static mut OUTPUT_OFFSET: Pointer = 0;
-
-/// Offset to the input data
-static mut OUTPUT_LENGTH: Length = 0;
-
-/// Current error message
-static mut ERROR: AtomicU64 = AtomicU64::new(0);
-
-/// Determines if the kernel has been initialized already
-static mut INITIALIZED: AtomicBool = AtomicBool::new(false);
-
-/// A pointer to the first page that will be managed by Extism, this is set during initialization
-static mut START_PAGE: usize = 0;
-
 /// Provides information about the usage status of a `MemoryBlock`
 #[repr(u8)]
 #[derive(PartialEq)]
@@ -98,10 +73,22 @@ pub enum MemoryStatus {
 /// including their data.
 #[repr(C)]
 pub struct MemoryRoot {
+    /// Set to true after initialization
+    pub initialized: AtomicBool,
     /// Position of the bump allocator, relative to `blocks` field
     pub position: AtomicU64,
     /// The total size of all data allocated using this allocator
     pub length: AtomicU64,
+    /// Offset of error block
+    pub error: AtomicU64,
+    /// Input position in memory
+    pub input_offset: Pointer,
+    /// Input length
+    pub input_length: Length,
+    /// Output position in memory
+    pub output_offset: Pointer,
+    /// Output length
+    pub output_length: Length,
     /// A pointer to the start of the first block
     pub blocks: [MemoryBlock; 0],
 }
@@ -131,32 +118,41 @@ pub fn num_pages(nbytes: u64) -> usize {
     }
 }
 
-// Get the `MemoryRoot` at the correct offset in memory
+// Get the `MemoryRoot`, this is always stored at offset 1 in memory
 #[inline]
 unsafe fn memory_root() -> &'static mut MemoryRoot {
-    &mut *((START_PAGE * PAGE_SIZE) as *mut MemoryRoot)
+    &mut *(1 as *mut MemoryRoot)
 }
 
 impl MemoryRoot {
     /// Initialize or load the `MemoryRoot` from the correct position in memory
     pub unsafe fn new() -> &'static mut MemoryRoot {
+        let root = memory_root();
+
         // If this fails then `INITIALIZED` is already `true` and we can just return the
         // already initialized `MemoryRoot`
-        if INITIALIZED
+        if root
+            .initialized
             .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
             .is_err()
         {
-            return memory_root();
+            return root;
         }
 
         // Ensure that at least one page is allocated to store the `MemoryRoot` data
-        START_PAGE = core::arch::wasm32::memory_grow(0, 1);
-        if START_PAGE == usize::MAX {
-            panic!("Out of memory");
+        if core::arch::wasm32::memory_size(0) == 0 {
+            if core::arch::wasm32::memory_grow(0, 1) == usize::MAX {
+                core::arch::wasm32::unreachable()
+            }
         }
 
+        root.input_offset = 0;
+        root.input_length = 0;
+        root.output_offset = 0;
+        root.output_length = 0;
+        root.error.store(0, Ordering::Release);
+
         // Initialize the `MemoryRoot` length, position and data
-        let root = memory_root();
         root.length.store(
             PAGE_SIZE as u64 - core::mem::size_of::<MemoryRoot>() as u64,
             Ordering::Release,
@@ -181,6 +177,11 @@ impl MemoryRoot {
             self.length.load(Ordering::Acquire) as usize,
         );
         self.position.store(0, Ordering::Release);
+        self.error.store(0, Ordering::Release);
+        self.input_offset = 0;
+        self.input_length = 0;
+        self.output_offset = 0;
+        self.output_length = 0;
     }
 
     #[inline(always)]
@@ -224,7 +225,7 @@ impl MemoryRoot {
             // Re-use freed blocks when they're large enough
             if status == MemoryStatus::Free as u8 && b.size >= length as usize {
                 // Split block if there is too much excess
-                if b.size - length as usize >= BLOCK_SPLIT_SIZE {
+                if b.size - length as usize >= 128 {
                     b.size -= length as usize;
                     b.used = 0;
 
@@ -348,14 +349,15 @@ pub unsafe fn extism_free(p: Pointer) {
     if p == 0 {
         return;
     }
-    let block = MemoryRoot::new().find_block(p);
+    let root = MemoryRoot::new();
+    let block = root.find_block(p);
     if let Some(block) = block {
         block.free();
 
         // If the input pointer is freed for some reason, make sure the input length to 0
         // since the original data is gone
-        if p == INPUT_OFFSET {
-            INPUT_LENGTH = 0;
+        if p == root.input_offset {
+            root.input_length = 0;
         }
     }
 }
@@ -396,21 +398,23 @@ pub unsafe fn extism_load_u64(p: Pointer) -> u64 {
 /// Load a byte from the input data
 #[no_mangle]
 pub unsafe fn extism_input_load_u8(p: Pointer) -> u8 {
+    let root = MemoryRoot::new();
     #[cfg(feature = "bounds-checking")]
-    if p >= INPUT_LENGTH {
+    if p >= root.input_length {
         return 0;
     }
-    *((INPUT_OFFSET + p) as *mut u8)
+    *((root.input_offset + p) as *mut u8)
 }
 
 /// Load a u64 from the input data
 #[no_mangle]
 pub unsafe fn extism_input_load_u64(p: Pointer) -> u64 {
+    let root = MemoryRoot::new();
     #[cfg(feature = "bounds-checking")]
-    if p + core::mem::size_of::<u64>() as Pointer > INPUT_LENGTH {
+    if p + core::mem::size_of::<u64>() as Pointer > root.input_length {
         return 0;
     }
-    *((INPUT_OFFSET + p) as *mut u64)
+    *((root.input_offset + p) as *mut u64)
 }
 
 /// Write a byte in Extism-managed memory
@@ -436,82 +440,83 @@ pub unsafe fn extism_store_u64(p: Pointer, x: u64) {
 /// Set the range of the input data in memory
 #[no_mangle]
 pub unsafe fn extism_input_set(p: Pointer, len: Length) {
+    let root = MemoryRoot::new();
     #[cfg(feature = "bounds-checking")]
     {
-        let root = MemoryRoot::new();
         if !root.pointer_in_bounds(p) || !root.pointer_in_bounds(p + len - 1) {
             return;
         }
     }
-    INPUT_OFFSET = p;
-    INPUT_LENGTH = len;
+    root.input_offset = p;
+    root.input_length = len;
 }
 
 /// Set the range of the output data in memory
 #[no_mangle]
 pub unsafe fn extism_output_set(p: Pointer, len: Length) {
+    let root = MemoryRoot::new();
     #[cfg(feature = "bounds-checking")]
     {
-        let root = MemoryRoot::new();
         if !root.pointer_in_bounds(p) || !root.pointer_in_bounds(p + len - 1) {
             return;
         }
     }
-    OUTPUT_OFFSET = p;
-    OUTPUT_LENGTH = len;
+    root.output_offset = p;
+    root.output_length = len;
 }
 
 /// Get the input length
 #[no_mangle]
 pub fn extism_input_length() -> Length {
-    unsafe { INPUT_LENGTH }
+    unsafe { MemoryRoot::new().input_length }
 }
 
 /// Get the input offset in Exitsm-managed memory
 #[no_mangle]
 pub fn extism_input_offset() -> Length {
-    unsafe { INPUT_OFFSET }
+    unsafe { MemoryRoot::new().input_offset }
 }
 
 /// Get the output length
 #[no_mangle]
-pub fn extism_output_length() -> Length {
-    unsafe { OUTPUT_LENGTH }
+pub unsafe fn extism_output_length() -> Length {
+    unsafe { MemoryRoot::new().output_length }
 }
 
 /// Get the output offset in Extism-managed memory
 #[no_mangle]
-pub fn extism_output_offset() -> Length {
-    unsafe { OUTPUT_OFFSET }
+pub unsafe fn extism_output_offset() -> Length {
+    MemoryRoot::new().output_offset
 }
 
 /// Reset the allocator
 #[no_mangle]
 pub unsafe fn extism_reset() {
-    ERROR.store(0, Ordering::SeqCst);
     MemoryRoot::new().reset()
 }
 
 /// Set the error message offset
 #[no_mangle]
 pub unsafe fn extism_error_set(ptr: Pointer) {
+    let root = MemoryRoot::new();
+
     // Allow ERROR to be set to 0
     if ptr == 0 {
-        ERROR.store(ptr, Ordering::SeqCst);
+        root.error.store(ptr, Ordering::SeqCst);
         return;
     }
 
     #[cfg(feature = "bounds-checking")]
-    if !MemoryRoot::new().pointer_in_bounds(ptr) {
+    if !root.pointer_in_bounds(ptr) {
         return;
     }
-    ERROR.store(ptr, Ordering::SeqCst);
+    root.error.store(ptr, Ordering::SeqCst);
 }
 
 /// Get the error message offset, if it's `0` then no error has been set
 #[no_mangle]
 pub unsafe fn extism_error_get() -> Pointer {
-    ERROR.load(Ordering::SeqCst)
+    MemoryRoot::new().error.load(Ordering::SeqCst)
 }
 
 /// Get the position of the allocator, this can be used as an indication of how many bytes are currently in-use

runtime/Cargo.toml

@@ -9,8 +9,8 @@ repository = "https://github.com/extism/extism"
 description = "Extism runtime and Rust SDK"
 
 [dependencies]
-wasmtime = ">= 13.0.0, < 15.0.0"
-wasmtime-wasi = ">= 13.0.0, < 15.0.0"
+wasmtime = ">= 14.0.0, < 15.0.0"
+wasmtime-wasi = ">= 14.0.0, < 15.0.0"
 anyhow = "1"
 serde = {version = "1", features = ["derive"]}
 serde_json = "1"

runtime/README.md

@@ -15,6 +15,16 @@ To use the `extism` crate, you can add it to your Cargo file:
 extism = "*"
 ```
 
+## Environment variables
+
+There are a few environment variables that can be used for debugging purposes:
+
+- `EXTISM_ENABLE_WASI_OUTPUT=1`: show WASI stdout/stderr
+- `EXTISM_MEMDUMP=extism.mem`: dump Extism linear memory to a file
+- `EXTISM_COREDUMP=extism.core`: write [coredump](https://github.com/WebAssembly/tool-conventions/blob/main/Coredump.md) to a file when a WebAssembly function traps
+- `EXTISM_DEBUG=1`: generate debug information
+- `EXTISM_PROFILE=perf|jitdump|vtune`: enable Wasmtime profiling
+
 ## Getting Started
 
 This guide should walk you through some of the concepts in Extism and the `extism` crate.
@@ -39,7 +49,7 @@ fn main() {
 }
 ```
 
-> **Note**: See [the Manifest docs](https://docs.rs/extism-manifest/0.5.0/extism_manifest/) as it has a rich schema and a lot of options.
+> **Note**: See [the Manifest docs](https://docs.rs/extism-manifest/extism_manifest/) as it has a rich schema and a lot of options.
 
 ### Calling A Plug-in's Exports
 

runtime/src/current_plugin.rs

@@ -258,16 +258,20 @@ impl CurrentPlugin {
 
     /// Get a pointer to the plugin memory
     pub(crate) fn memory_ptr(&mut self) -> *mut u8 {
-        let (linker, mut store) = self.linker_and_store();
-        if let Some(mem) = linker.get(&mut store, "env", "memory") {
-            if let Some(mem) = mem.into_memory() {
-                return mem.data_ptr(&mut store);
-            }
+        if let Some(mem) = self.memory() {
+            let (_, mut store) = self.linker_and_store();
+            return mem.data_ptr(&mut store);
         }
 
         std::ptr::null_mut()
     }
 
+    /// Get extism memory
+    pub(crate) fn memory(&mut self) -> Option<wasmtime::Memory> {
+        let (linker, mut store) = self.linker_and_store();
+        linker.get(&mut store, "env", "memory")?.into_memory()
+    }
+
     /// Get a `MemoryHandle` from a `Val` reference - this can be used to convert a host function's
     /// argument directly to `MemoryHandle`
     pub fn memory_from_val(&mut self, offs: &Val) -> Option<MemoryHandle> {

runtime/src/lib.rs

@@ -27,6 +27,7 @@ pub use plugin_builder::PluginBuilder;
 
 pub(crate) use internal::{Internal, Wasi};
 pub(crate) use log::{debug, error, trace};
+pub(crate) use plugin_builder::DebugOptions;
 pub(crate) use timer::{Timer, TimerAction};
 
 #[cfg(test)]

runtime/src/plugin.rs

@@ -70,6 +70,8 @@ pub struct Plugin {
     /// Set to `true` when de-initializarion may have occured (i.e.a call to `_start`),
     /// in this case we need to re-initialize the entire module.
     pub(crate) needs_reset: bool,
+
+    pub(crate) debug_options: DebugOptions,
 }
 
 unsafe impl Send for Plugin {}
@@ -108,6 +110,8 @@ const EXPORT_MODULE_NAME: &str = "env";
 fn profiling_strategy() -> ProfilingStrategy {
     match std::env::var("EXTISM_PROFILE").as_deref() {
         Ok("perf") => ProfilingStrategy::PerfMap,
+        Ok("jitdump") => ProfilingStrategy::JitDump,
+        Ok("vtune") => ProfilingStrategy::VTune,
         Ok(x) => {
             log::warn!("Invalid value for EXTISM_PROFILE: {x}");
             ProfilingStrategy::None
@@ -116,12 +120,6 @@ fn profiling_strategy() -> ProfilingStrategy {
     }
 }
 
-// Raise an error when the epoch deadline is encountered - this is used for timeout/cancellation
-// to stop a plugin that is executing
-fn deadline_callback(_: StoreContextMut<CurrentPlugin>) -> Result<UpdateDeadline, Error> {
-    Err(Error::msg("timeout"))
-}
-
 impl Plugin {
     /// Create a new plugin from the given manifest, and host functions. The `with_wasi` parameter determines
     /// whether or not the module should be executed with WASI enabled.
@@ -141,13 +139,36 @@ impl Plugin {
         imports: impl IntoIterator<Item = Function>,
         with_wasi: bool,
     ) -> Result<Plugin, Error> {
-        // Create a new engine, if the `EXTISM_DEBUG` environment variable is set
-        // then we enable debug info
+        Self::build_new(wasm, imports, with_wasi, Default::default())
+    }
+
+    pub(crate) fn build_new(
+        wasm: impl AsRef<[u8]>,
+        imports: impl IntoIterator<Item = Function>,
+        with_wasi: bool,
+        mut debug_options: DebugOptions,
+    ) -> Result<Plugin, Error> {
+        // Configure debug options
+        debug_options.debug_info =
+            debug_options.debug_info || std::env::var("EXTISM_DEBUG").is_ok();
+        if let Ok(x) = std::env::var("EXTISM_COREDUMP") {
+            debug_options.coredump = Some(std::path::PathBuf::from(x));
+        };
+        if let Ok(x) = std::env::var("EXTISM_MEMDUMP") {
+            debug_options.memdump = Some(std::path::PathBuf::from(x));
+        };
+        let profiling_strategy = debug_options
+            .profiling_strategy
+            .map_or(ProfilingStrategy::None, |_| profiling_strategy());
+        debug_options.profiling_strategy = Some(profiling_strategy.clone());
+
+        // Setup wasmtime types
         let engine = Engine::new(
             Config::new()
                 .epoch_interruption(true)
-                .debug_info(std::env::var("EXTISM_DEBUG").is_ok())
-                .profiler(profiling_strategy()),
+                .debug_info(debug_options.debug_info)
+                .coredump_on_trap(debug_options.coredump.is_some())
+                .profiler(profiling_strategy),
         )?;
         let mut imports = imports.into_iter();
         let (manifest, modules) = manifest::load(&engine, wasm.as_ref())?;
@@ -245,6 +266,7 @@ impl Plugin {
             output: Output::default(),
             _functions: imports.collect(),
             needs_reset: false,
+            debug_options,
         };
 
         plugin.current_plugin_mut().store = &mut plugin.store;
@@ -576,11 +598,10 @@ impl Plugin {
                     .map(std::time::Duration::from_millis),
             })
             .unwrap();
-        self.store.epoch_deadline_callback(deadline_callback);
 
         // Call the function
         let mut results = vec![wasmtime::Val::null(); n_results];
-        let res = func.call(self.store_mut(), &[], results.as_mut_slice());
+        let mut res = func.call(self.store_mut(), &[], results.as_mut_slice());
 
         // Stop timer
         self.timer_tx
@@ -592,13 +613,24 @@ impl Plugin {
         self.get_output_after_call();
         self.needs_reset = name == "_start";
 
+        let mut msg = None;
+
         if self.output.error_offset != 0 && self.output.error_length != 0 {
             let handle = MemoryHandle {
                 offset: self.output.error_offset,
                 length: self.output.error_length,
             };
             if let Ok(e) = self.current_plugin_mut().memory_str(handle) {
-                return Err((Error::msg(e.to_string()), -1));
+                let x = e.to_string();
+                error!("Call to {name} returned with error message: {}", x);
+
+                // If `res` is `Ok` and there is an error message set, then convert the response
+                // to an `Error`
+                if res.is_ok() {
+                    res = Err(Error::msg(x));
+                } else {
+                    msg = Some(x);
+                }
             }
         }
 
@@ -613,24 +645,69 @@ impl Plugin {
                 // Return result to caller
                 Ok(0)
             }
-            Err(e) => match e.downcast::<wasmtime_wasi::I32Exit>() {
-                Ok(exit) => {
-                    trace!("WASI return code: {}", exit.0);
-                    if exit.0 != 0 {
-                        return Err((Error::msg("WASI return code"), exit.0));
+            Err(e) => {
+                if let Some(coredump) = e.downcast_ref::<wasmtime::WasmCoreDump>() {
+                    if let Some(file) = self.debug_options.coredump.clone() {
+                        debug!("Saving coredump to {}", file.display());
+
+                        if let Err(e) =
+                            std::fs::write(file, coredump.serialize(self.store_mut(), "extism"))
+                        {
+                            error!("Unable to write coredump: {:?}", e);
+                        }
                     }
-                    return Ok(0);
                 }
-                Err(e) => {
-                    let cause = e.root_cause().to_string();
-                    if cause == "timeout" || cause == "oom" {
-                        return Err((Error::msg(cause), -1));
+
+                if let Some(file) = &self.debug_options.memdump.clone() {
+                    trace!("Memory dump enabled");
+                    if let Some(memory) = self.current_plugin_mut().memory() {
+                        debug!("Dumping memory to {}", file.display());
+                        let data = memory.data(&mut self.store);
+                        if let Err(e) = std::fs::write(file, &data) {
+                            error!("Unable to write memory dump: {:?}", e);
+                        }
+                    } else {
+                        error!("Unable to get extism memory for writing to disk");
+                    }
+                }
+
+                let wasi_exit_code = e
+                    .downcast_ref::<wasmtime_wasi::I32Exit>()
+                    .map(|e| e.0)
+                    .or_else(|| {
+                        e.downcast_ref::<wasmtime_wasi::preview2::I32Exit>()
+                            .map(|e| e.0)
+                    });
+                if let Some(exit_code) = wasi_exit_code {
+                    trace!("WASI exit code: {}", exit_code);
+                    if exit_code == 0 && msg.is_none() {
+                        return Ok(0);
                     }
 
-                    error!("Call: {e:?}");
-                    return Err((e.context("Call failed"), -1));
+                    return Err((
+                        Error::msg(msg.unwrap_or_else(|| "WASI exit code".to_string())),
+                        exit_code,
+                    ));
                 }
-            },
+
+                // Handle timeout interrupts
+                if let Some(wasmtime::Trap::Interrupt) = e.downcast_ref::<wasmtime::Trap>() {
+                    trace!("Call to {name} timed out");
+                    return Err((Error::msg("timeout"), -1));
+                }
+
+                // Handle out-of-memory error from `MemoryLimiter`
+                let cause = e.root_cause().to_string();
+                if cause == "oom" {
+                    return Err((Error::msg(cause), -1));
+                }
+
+                error!("Call to {name} encountered an error: {e:?}");
+                return Err((
+                    e.context(msg.unwrap_or_else(|| "Error in Extism plugin call".to_string())),
+                    -1,
+                ));
+            }
         }
     }
 
@@ -718,7 +795,7 @@ pub(crate) enum GuestRuntime {
 ///
 /// # const WASM: &[u8] = include_bytes!("../../wasm/code.wasm");
 /// // Convert from `Plugin` to `MyPlugin`
-/// let mut plugin: MyPlugin = extism::Plugin::new(WASM, [], true).unwrap().into();
+/// let mut plugin: MyPlugin = extism::Plugin::new(WASM, [], true).unwrap().try_into().unwrap();
 /// // and call the `count_vowels` function
 /// let count = plugin.count_vowels("this is a test").unwrap();
 /// ```
@@ -730,9 +807,15 @@ macro_rules! typed_plugin {
         unsafe impl Send for $name {}
         unsafe impl Sync for $name {}
 
-        impl From<$crate::Plugin> for $name {
-            fn from(x: $crate::Plugin) -> Self {
-                $name(x)
+        impl TryFrom<$crate::Plugin> for $name {
+            type Error = $crate::Error;
+            fn try_from(mut x: $crate::Plugin) -> Result<Self, Self::Error> {
+                $(
+                    if !x.function_exists(stringify!($f)) {
+                        return Err($crate::Error::msg(format!("Invalid function: {}", stringify!($f))));
+                    }
+                )*
+                Ok($name(x))
             }
         }
 

runtime/src/plugin_builder.rs

@@ -5,11 +5,20 @@ enum Source {
     Data(Vec<u8>),
 }
 
+#[derive(Default, Clone)]
+pub(crate) struct DebugOptions {
+    pub(crate) profiling_strategy: Option<wasmtime::ProfilingStrategy>,
+    pub(crate) coredump: Option<std::path::PathBuf>,
+    pub(crate) memdump: Option<std::path::PathBuf>,
+    pub(crate) debug_info: bool,
+}
+
 /// PluginBuilder is used to configure and create `Plugin` instances
 pub struct PluginBuilder {
     source: Source,
     wasi: bool,
     functions: Vec<Function>,
+    debug_options: DebugOptions,
 }
 
 impl PluginBuilder {
@@ -19,6 +28,7 @@ impl PluginBuilder {
             source: Source::Data(data.into()),
             wasi: false,
             functions: vec![],
+            debug_options: DebugOptions::default(),
         }
     }
 
@@ -28,6 +38,7 @@ impl PluginBuilder {
             source: Source::Manifest(manifest),
             wasi: false,
             functions: vec![],
+            debug_options: DebugOptions::default(),
         }
     }
 
@@ -68,11 +79,34 @@ impl PluginBuilder {
         self
     }
 
+    pub fn with_profiling_strategy(mut self, p: wasmtime::ProfilingStrategy) -> Self {
+        self.debug_options.profiling_strategy = Some(p);
+        self
+    }
+
+    pub fn with_coredump(mut self, path: impl AsRef<std::path::Path>) -> Self {
+        self.debug_options.coredump = Some(path.as_ref().to_path_buf());
+        self
+    }
+
+    pub fn with_memdump(mut self, path: impl AsRef<std::path::Path>) -> Self {
+        self.debug_options.memdump = Some(path.as_ref().to_path_buf());
+        self
+    }
+
+    pub fn with_debug_info(mut self) -> Self {
+        self.debug_options.debug_info = true;
+        self
+    }
+
     /// Generate a new plugin with the configured settings
     pub fn build(self) -> Result<Plugin, Error> {
         match self.source {
-            Source::Manifest(m) => Plugin::new_with_manifest(&m, self.functions, self.wasi),
-            Source::Data(d) => Plugin::new(d, self.functions, self.wasi),
+            Source::Manifest(m) => {
+                let data = serde_json::to_vec(&m)?;
+                Plugin::build_new(&data, self.functions, self.wasi, self.debug_options)
+            }
+            Source::Data(d) => Plugin::build_new(d, self.functions, self.wasi, self.debug_options),
         }
     }
 }

runtime/src/tests/runtime.rs

@@ -214,7 +214,9 @@ fn test_timeout() {
     let end = std::time::Instant::now();
     let time = end - start;
     println!("Timed out plugin ran for {:?}", time);
-    assert!(output.unwrap_err().root_cause().to_string() == "timeout");
+    let s = output.unwrap_err().root_cause().to_string();
+    println!("{}", s);
+    assert!(s == "timeout");
     // std::io::stdout().write_all(output).unwrap();
 }
 
@@ -236,7 +238,7 @@ fn test_typed_plugin_macro() {
         hello_world,
     );
 
-    let mut plugin: CountVowelsPlugin = Plugin::new(WASM, [f], true).unwrap().into();
+    let mut plugin: CountVowelsPlugin = Plugin::new(WASM, [f], true).unwrap().try_into().unwrap();
 
     let Json(output0): Json<Count> = plugin.count_vowels("abc123").unwrap();
     let Json(output1): Json<Count> = plugin.0.call("count_vowels", "abc123").unwrap();
@@ -254,7 +256,7 @@ fn test_multiple_instantiations() {
         hello_world,
     );
 
-    let mut plugin: CountVowelsPlugin = Plugin::new(WASM, [f], true).unwrap().into();
+    let mut plugin: CountVowelsPlugin = Plugin::new(WASM, [f], true).unwrap().try_into().unwrap();
 
     // This is 10,001 because the wasmtime store limit is 10,000 - we want to test
     // that our reinstantiation process is working and that limit is never hit.
@@ -314,7 +316,10 @@ fn test_memory_max() {
     let mut plugin = Plugin::new_with_manifest(&manifest, [], true).unwrap();
     let output: Result<String, Error> = plugin.call("count_vowels", "a".repeat(65536 * 2));
     assert!(output.is_err());
-    assert!(output.unwrap_err().root_cause().to_string() == "oom");
+
+    let err = output.unwrap_err().root_cause().to_string();
+    println!("{:?}", err);
+    assert_eq!(err, "oom");
 
     // Should pass with memory.max set to a large enough number
     let manifest =
@@ -356,3 +361,47 @@ fn test_extism_error() {
     assert!(output.is_err());
     assert_eq!(output.unwrap_err().root_cause().to_string(), "TEST");
 }
+
+#[test]
+fn test_extism_memdump() {
+    let f = Function::new(
+        "hello_world",
+        [ValType::I64],
+        [ValType::I64],
+        None,
+        hello_world_set_error,
+    );
+    let mut plugin = PluginBuilder::new_with_module(WASM)
+        .with_wasi(true)
+        .with_functions([f])
+        .with_memdump("extism.mem")
+        .build()
+        .unwrap();
+    let output: Result<String, Error> = plugin.call("count_vowels", "a".repeat(1024));
+    assert!(output.is_err());
+    assert!(std::path::PathBuf::from("extism.mem").exists());
+    let _ = std::fs::remove_file("extism.mem");
+}
+
+#[test]
+fn test_extism_coredump() {
+    let f = Function::new(
+        "hello_world",
+        [ValType::I64],
+        [ValType::I64],
+        None,
+        hello_world_set_error,
+    );
+    let manifest = Manifest::new([extism_manifest::Wasm::data(WASM_LOOP)])
+        .with_timeout(std::time::Duration::from_secs(1));
+    let mut plugin = PluginBuilder::new(manifest)
+        .with_wasi(true)
+        .with_functions([f])
+        .with_coredump("extism.core")
+        .build()
+        .unwrap();
+    let output: Result<&[u8], Error> = plugin.call("infinite_loop", "abc123");
+    assert!(output.is_err());
+    assert!(std::path::PathBuf::from("extism.core").exists());
+    let _ = std::fs::remove_file("extism.core");
+}