Remove lifetime parameter of inprocess executors (#3524)

For any `H: FnMut(...) -> T`, it is also the case that `&mut H:
FnMut(...) -> T`. Thus, changing from `&mut H` to just `H` gives API
clients more flexibility. They can still pass a `&mut` reference if
they want to (as evidenced by not needing any changes in the example
fuzzers), but they can also now pass an owned `H`. A client might want
to do this  to pass a `Box` they just allocated and don't want to hold
onto.

This also allows for removing some ubiquitous lifetime parameters, which
is a nice simplification.

Also, sprinkle a few `#[must_use]`s around while I'm in the area.

Author: langston-barrett

crates/libafl/src/executors/inprocess/mod.rs

@@ -36,12 +36,12 @@ pub mod inner;
 pub mod stateful;
 
 /// The process executor simply calls a target function, as mutable reference to a closure.
-pub type InProcessExecutor<'a, EM, H, I, OT, S, Z> =
-    GenericInProcessExecutor<EM, H, &'a mut H, (), I, OT, S, Z>;
+pub type InProcessExecutor<EM, H, I, OT, S, Z> =
+    GenericInProcessExecutor<EM, H, H, (), I, OT, S, Z>;
 
 /// The inprocess executor that allows hooks
-pub type HookableInProcessExecutor<'a, EM, H, HT, I, OT, S, Z> =
-    GenericInProcessExecutor<EM, H, &'a mut H, HT, I, OT, S, Z>;
+pub type HookableInProcessExecutor<EM, H, HT, I, OT, S, Z> =
+    GenericInProcessExecutor<EM, H, H, HT, I, OT, S, Z>;
 /// The process executor simply calls a target function, as boxed `FnMut` trait object
 pub type OwnedInProcessExecutor<EM, I, OT, S, Z> = GenericInProcessExecutor<
     EM,
@@ -124,7 +124,7 @@ impl<EM, H, HB, HT, I, OT, S, Z> HasObservers
     }
 }
 
-impl<'a, EM, H, I, OT, S, Z> InProcessExecutor<'a, EM, H, I, OT, S, Z>
+impl<EM, H, I, OT, S, Z> InProcessExecutor<EM, H, I, OT, S, Z>
 where
     H: FnMut(&I) -> ExitKind + Sized,
     OT: ObserversTuple<I, S>,
@@ -133,7 +133,7 @@ where
 {
     /// Create a new in mem executor with the default timeout (5 sec)
     pub fn new<OF>(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         observers: OT,
         fuzzer: &mut Z,
         state: &mut S,
@@ -164,7 +164,7 @@ where
     ///
     /// This may return an error on unix, if signal handler setup fails
     pub fn with_timeout<OF>(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         observers: OT,
         fuzzer: &mut Z,
         state: &mut S,
@@ -262,24 +262,28 @@ where
 
     /// Retrieve the harness function.
     #[inline]
+    #[must_use]
     pub fn harness(&self) -> &H {
         self.harness_fn.borrow()
     }
 
     /// Retrieve the harness function for a mutable reference.
     #[inline]
+    #[must_use]
     pub fn harness_mut(&mut self) -> &mut H {
         self.harness_fn.borrow_mut()
     }
 
     /// The inprocess handlers
     #[inline]
+    #[must_use]
     pub fn hooks(&self) -> &(InProcessHooks<I, S>, HT) {
         self.inner.hooks()
     }
 
     /// The inprocess handlers (mutable)
     #[inline]
+    #[must_use]
     pub fn hooks_mut(&mut self) -> &mut (InProcessHooks<I, S>, HT) {
         self.inner.hooks_mut()
     }

crates/libafl/src/executors/inprocess/stateful.rs

@@ -27,8 +27,8 @@ use crate::{
 
 /// The process executor simply calls a target function, as mutable reference to a closure
 /// The internal state of the executor is made available to the harness.
-pub type StatefulInProcessExecutor<'a, EM, ES, H, I, OT, S, Z> =
-    StatefulGenericInProcessExecutor<EM, ES, H, &'a mut H, (), I, OT, S, Z>;
+pub type StatefulInProcessExecutor<EM, ES, H, I, OT, S, Z> =
+    StatefulGenericInProcessExecutor<EM, ES, H, H, (), I, OT, S, Z>;
 
 /// The process executor simply calls a target function, as boxed `FnMut` trait object
 /// The internal state of the executor is made available to the harness.
@@ -123,7 +123,7 @@ where
     }
 }
 
-impl<'a, EM, ES, H, I, OT, S, Z> StatefulInProcessExecutor<'a, EM, ES, H, I, OT, S, Z>
+impl<EM, ES, H, I, OT, S, Z> StatefulInProcessExecutor<EM, ES, H, I, OT, S, Z>
 where
     H: FnMut(&mut ES, &mut S, &I) -> ExitKind + Sized,
     OT: ObserversTuple<I, S>,
@@ -132,7 +132,7 @@ where
 {
     /// Create a new in mem executor with the default timeout (5 sec)
     pub fn new<OF>(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         exposed_executor_state: ES,
         observers: OT,
         fuzzer: &mut Z,
@@ -165,7 +165,7 @@ where
     ///
     /// This may return an error on unix, if signal handler setup fails
     pub fn with_timeout<OF>(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         exposed_executor_state: ES,
         observers: OT,
         fuzzer: &mut Z,

crates/libafl/src/executors/inprocess_fork/mod.rs

@@ -39,16 +39,16 @@ pub mod stateful;
 ///
 /// On Linux, when fuzzing a Rust target, set `panic = "abort"` in your `Cargo.toml` (see [Cargo documentation](https://doc.rust-lang.org/cargo/reference/profiles.html#panic)).
 /// Else panics can not be caught by `LibAFL`.
-pub type InProcessForkExecutor<'a, EM, H, I, OT, S, SP, Z> =
-    GenericInProcessForkExecutor<'a, EM, H, (), I, OT, S, SP, Z>;
+pub type InProcessForkExecutor<EM, H, I, OT, S, SP, Z> =
+    GenericInProcessForkExecutor<EM, H, (), I, OT, S, SP, Z>;
 
-impl<'a, H, I, OT, S, SP, EM, Z> InProcessForkExecutor<'a, EM, H, I, OT, S, SP, Z>
+impl<H, I, OT, S, SP, EM, Z> InProcessForkExecutor<EM, H, I, OT, S, SP, Z>
 where
     OT: ObserversTuple<I, S>,
 {
     /// The constructor for `InProcessForkExecutor`
     pub fn new(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         observers: OT,
         fuzzer: &mut Z,
         state: &mut S,
@@ -73,13 +73,12 @@ where
 ///
 /// On Linux, when fuzzing a Rust target, set `panic = "abort"` in your `Cargo.toml` (see [Cargo documentation](https://doc.rust-lang.org/cargo/reference/profiles.html#panic)).
 /// Else panics can not be caught by `LibAFL`.
-pub struct GenericInProcessForkExecutor<'a, EM, H, HT, I, OT, S, SP, Z> {
-    harness_fn: &'a mut H,
+pub struct GenericInProcessForkExecutor<EM, H, HT, I, OT, S, SP, Z> {
+    harness_fn: H,
     inner: GenericInProcessForkExecutorInner<EM, HT, I, OT, S, SP, Z>,
 }
 
-impl<H, HT, I, OT, S, SP, EM, Z> Debug
-    for GenericInProcessForkExecutor<'_, EM, H, HT, I, OT, S, SP, Z>
+impl<H, HT, I, OT, S, SP, EM, Z> Debug for GenericInProcessForkExecutor<EM, H, HT, I, OT, S, SP, Z>
 where
     HT: Debug,
     OT: Debug,
@@ -103,7 +102,7 @@ where
 }
 
 impl<EM, H, HT, I, OT, S, SP, Z> Executor<EM, I, S, Z>
-    for GenericInProcessForkExecutor<'_, EM, H, HT, I, OT, S, SP, Z>
+    for GenericInProcessForkExecutor<EM, H, HT, I, OT, S, SP, Z>
 where
     H: FnMut(&I) -> ExitKind + Sized,
     HT: ExecutorHooksTuple<I, S>,
@@ -141,7 +140,7 @@ where
     }
 }
 
-impl<'a, H, HT, I, OT, S, SP, EM, Z> GenericInProcessForkExecutor<'a, EM, H, HT, I, OT, S, SP, Z>
+impl<H, HT, I, OT, S, SP, EM, Z> GenericInProcessForkExecutor<EM, H, HT, I, OT, S, SP, Z>
 where
     HT: ExecutorHooksTuple<I, S>,
     OT: ObserversTuple<I, S>,
@@ -150,15 +149,14 @@ where
     #[expect(clippy::too_many_arguments)]
     pub fn with_hooks(
         userhooks: HT,
-        harness_fn: &'a mut H,
+        harness_fn: H,
         observers: OT,
         fuzzer: &mut Z,
         state: &mut S,
         event_mgr: &mut EM,
         timeout: Duration,
         shmem_provider: SP,
-    ) -> Result<Self, Error>
-where {
+    ) -> Result<Self, Error> {
         Ok(Self {
             harness_fn,
             inner: GenericInProcessForkExecutorInner::with_hooks(
@@ -175,19 +173,21 @@ where {
 
     /// Retrieve the harness function.
     #[inline]
+    #[must_use]
     pub fn harness(&self) -> &H {
-        self.harness_fn
+        &self.harness_fn
     }
 
     /// Retrieve the harness function for a mutable reference.
     #[inline]
+    #[must_use]
     pub fn harness_mut(&mut self) -> &mut H {
-        self.harness_fn
+        &mut self.harness_fn
     }
 }
 
 impl<H, HT, I, OT, S, SP, EM, Z> HasObservers
-    for GenericInProcessForkExecutor<'_, EM, H, HT, I, OT, S, SP, Z>
+    for GenericInProcessForkExecutor<EM, H, HT, I, OT, S, SP, Z>
 {
     type Observers = OT;
     #[inline]

crates/libafl/src/executors/inprocess_fork/stateful.rs

@@ -24,18 +24,18 @@ use crate::{
 };
 
 /// The `StatefulInProcessForkExecutor` with no user hooks
-pub type StatefulInProcessForkExecutor<'a, EM, ES, H, I, OT, S, SP, Z> =
-    StatefulGenericInProcessForkExecutor<'a, EM, ES, H, (), I, OT, S, SP, Z>;
+pub type StatefulInProcessForkExecutor<EM, ES, H, I, OT, S, SP, Z> =
+    StatefulGenericInProcessForkExecutor<EM, ES, H, (), I, OT, S, SP, Z>;
 
-impl<'a, H, I, OT, S, SP, EM, ES, Z> StatefulInProcessForkExecutor<'a, EM, ES, H, I, OT, S, SP, Z>
+impl<H, I, OT, S, SP, EM, ES, Z> StatefulInProcessForkExecutor<EM, ES, H, I, OT, S, SP, Z>
 where
     OT: ObserversTuple<I, S>,
     SP: ShMemProvider,
 {
     #[expect(clippy::too_many_arguments)]
     /// The constructor for `InProcessForkExecutor`
     pub fn new(
-        harness_fn: &'a mut H,
+        harness_fn: H,
         exposed_executor_state: ES,
         observers: OT,
         fuzzer: &mut Z,
@@ -59,17 +59,17 @@ where
 }
 
 /// [`StatefulGenericInProcessForkExecutor`] is an executor that forks the current process before each execution. Harness can access some internal state.
-pub struct StatefulGenericInProcessForkExecutor<'a, EM, ES, H, HT, I, OT, S, SP, Z> {
+pub struct StatefulGenericInProcessForkExecutor<EM, ES, H, HT, I, OT, S, SP, Z> {
     /// The harness function, being executed for each fuzzing loop execution
-    harness_fn: &'a mut H,
+    harness_fn: H,
     /// The state used as argument of the harness
     pub exposed_executor_state: ES,
     /// Inner state of the executor
     pub inner: GenericInProcessForkExecutorInner<EM, HT, I, OT, S, SP, Z>,
 }
 
 impl<H, HT, I, OT, S, SP, EM, ES, Z> Debug
-    for StatefulGenericInProcessForkExecutor<'_, EM, ES, H, HT, I, OT, S, SP, Z>
+    for StatefulGenericInProcessForkExecutor<EM, ES, H, HT, I, OT, S, SP, Z>
 where
     HT: Debug,
     OT: Debug,
@@ -93,7 +93,7 @@ where
 }
 
 impl<EM, H, HT, I, OT, S, SP, Z, ES> Executor<EM, I, S, Z>
-    for StatefulGenericInProcessForkExecutor<'_, EM, ES, H, HT, I, OT, S, SP, Z>
+    for StatefulGenericInProcessForkExecutor<EM, ES, H, HT, I, OT, S, SP, Z>
 where
     H: FnMut(&mut ES, &I) -> ExitKind + Sized,
     HT: ExecutorHooksTuple<I, S>,
@@ -134,8 +134,8 @@ where
     }
 }
 
-impl<'a, H, HT, I, OT, S, SP, EM, ES, Z>
-    StatefulGenericInProcessForkExecutor<'a, EM, ES, H, HT, I, OT, S, SP, Z>
+impl<H, HT, I, OT, S, SP, EM, ES, Z>
+    StatefulGenericInProcessForkExecutor<EM, ES, H, HT, I, OT, S, SP, Z>
 where
     HT: ExecutorHooksTuple<I, S>,
     OT: ObserversTuple<I, S>,
@@ -144,7 +144,7 @@ where
     #[expect(clippy::too_many_arguments)]
     pub fn with_hooks(
         userhooks: HT,
-        harness_fn: &'a mut H,
+        harness_fn: H,
         exposed_executor_state: ES,
         observers: OT,
         fuzzer: &mut Z,
@@ -170,19 +170,21 @@ where
 
     /// Retrieve the harness function.
     #[inline]
+    #[must_use]
     pub fn harness(&self) -> &H {
-        self.harness_fn
+        &self.harness_fn
     }
 
     /// Retrieve the harness function for a mutable reference.
     #[inline]
+    #[must_use]
     pub fn harness_mut(&mut self) -> &mut H {
-        self.harness_fn
+        &mut self.harness_fn
     }
 }
 
 impl<H, HT, I, OT, S, SP, EM, ES, Z> HasObservers
-    for StatefulGenericInProcessForkExecutor<'_, EM, ES, H, HT, I, OT, S, SP, Z>
+    for StatefulGenericInProcessForkExecutor<EM, ES, H, HT, I, OT, S, SP, Z>
 {
     type Observers = OT;