Added Truncate trait (#1141)

fuzzers/forkserver_libafl_cc/src/main.rs

@@ -180,7 +180,7 @@ pub fn main() {
             .observers_mut()
             .match_name_mut::<HitcountsMapObserver<StdMapObserver<'_, u8, false>>>("shared_mem")
             .unwrap()
-            .downsize_map(dynamic_map_size);
+            .truncate(dynamic_map_size);
     }
 
     let mut executor = TimeoutForkserverExecutor::with_signal(

fuzzers/forkserver_simple/src/main.rs

@@ -180,7 +180,7 @@ pub fn main() {
             .observers_mut()
             .match_name_mut::<HitcountsMapObserver<StdMapObserver<'_, u8, false>>>("shared_mem")
             .unwrap()
-            .downsize_map(dynamic_map_size);
+            .truncate(dynamic_map_size);
     }
 
     let mut executor = TimeoutForkserverExecutor::with_signal(

libafl/src/bolts/mod.rs

@@ -154,6 +154,12 @@ pub trait HasRefCnt {
     fn refcnt_mut(&mut self) -> &mut isize;
 }
 
+/// Trait to truncate slices and maps to a new size
+pub trait Truncate {
+    /// Reduce the size of the slice
+    fn truncate(&mut self, len: usize);
+}
+
 /// Current time
 #[cfg(feature = "std")]
 #[must_use]

libafl/src/bolts/ownedref.rs

@@ -10,7 +10,7 @@ use core::{clone::Clone, fmt::Debug, slice};
 
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
-use crate::bolts::{AsMutSlice, AsSlice};
+use crate::bolts::{AsMutSlice, AsSlice, Truncate};
 
 /// Trait to convert into an Owned type
 pub trait IntoOwned {
@@ -23,20 +23,14 @@ pub trait IntoOwned {
     fn into_owned(self) -> Self;
 }
 
-/// Trait to downsize slice references
+impl<'a, T> Truncate for &'a [T] {
-pub trait DownsizeSlice {
+    fn truncate(&mut self, len: usize) {
-    /// Reduce the size of the slice
-    fn downsize(&mut self, len: usize);
-}
-
-impl<'a, T> DownsizeSlice for &'a [T] {
-    fn downsize(&mut self, len: usize) {
         *self = &self[..len];
     }
 }
 
-impl<'a, T> DownsizeSlice for &'a mut [T] {
+impl<'a, T> Truncate for &'a mut [T] {
-    fn downsize(&mut self, len: usize) {
+    fn truncate(&mut self, len: usize) {
         let mut value = core::mem::take(self);
         value = unsafe { value.get_unchecked_mut(..len) };
         let _: &mut [T] = core::mem::replace(self, value);
@@ -260,8 +254,8 @@ impl<'a, T> OwnedSlice<'a, T> {
         }
     }
 
-    /// Downsize the inner slice or vec returning the old size on success or `None` on failure
+    /// Truncate the inner slice or vec returning the old size on success or `None` on failure
-    pub fn downsize(&mut self, new_len: usize) -> Option<usize> {
+    pub fn truncate(&mut self, new_len: usize) -> Option<usize> {
         match &mut self.inner {
             OwnedSliceInner::RefRaw(_rr, len) => {
                 let tmp = *len;
@@ -275,7 +269,7 @@ impl<'a, T> OwnedSlice<'a, T> {
             OwnedSliceInner::Ref(r) => {
                 let tmp = r.len();
                 if new_len <= tmp {
-                    r.downsize(new_len);
+                    r.truncate(new_len);
                     Some(tmp)
                 } else {
                     None
@@ -483,8 +477,8 @@ impl<'a, T: 'a + Sized> OwnedMutSlice<'a, T> {
         }
     }
 
-    /// Downsize the inner slice or vec returning the old size on success or `None` on failure
+    /// Truncate the inner slice or vec returning the old size on success or `None` on failure
-    pub fn downsize(&mut self, new_len: usize) -> Option<usize> {
+    pub fn truncate(&mut self, new_len: usize) -> Option<usize> {
         match &mut self.inner {
             OwnedMutSliceInner::RefRaw(_rr, len) => {
                 let tmp = *len;
@@ -498,7 +492,7 @@ impl<'a, T: 'a + Sized> OwnedMutSlice<'a, T> {
             OwnedMutSliceInner::Ref(r) => {
                 let tmp = r.len();
                 if new_len <= tmp {
-                    r.downsize(new_len);
+                    r.truncate(new_len);
                     Some(tmp)
                 } else {
                     None

libafl/src/executors/forkserver.rs

@@ -32,7 +32,7 @@ use crate::{
         os::{dup2, pipes::Pipe},
         shmem::{ShMem, ShMemProvider, UnixShMemProvider},
         tuples::Prepend,
-        AsMutSlice, AsSlice,
+        AsMutSlice, AsSlice, Truncate,
     },
     executors::{Executor, ExitKind, HasObservers},
     inputs::{HasTargetBytes, Input, UsesInput},
@@ -653,7 +653,7 @@ impl<'a, SP> ForkserverExecutorBuilder<'a, SP> {
         other_observers: OT,
     ) -> Result<ForkserverExecutor<(MO, OT), S, SP>, Error>
     where
-        MO: Observer<S> + MapObserver, // TODO maybe enforce Entry = u8 for the cov map
+        MO: Observer<S> + MapObserver + Truncate, // TODO maybe enforce Entry = u8 for the cov map
         OT: ObserversTuple<S> + Prepend<MO, PreprendResult = OT>,
         S: UsesInput,
         S::Input: Input + HasTargetBytes,
@@ -671,7 +671,7 @@ impl<'a, SP> ForkserverExecutorBuilder<'a, SP> {
         );
 
         if let Some(dynamic_map_size) = self.map_size {
-            map_observer.downsize_map(dynamic_map_size);
+            map_observer.truncate(dynamic_map_size);
         }
 
         let observers: (MO, OT) = other_observers.prepend(map_observer);

libafl/src/observers/map.rs

@@ -21,7 +21,7 @@ use crate::{
     bolts::{
         ownedref::{OwnedMutPtr, OwnedMutSlice},
         tuples::Named,
-        AsIter, AsIterMut, AsMutSlice, AsSlice, HasLen,
+        AsIter, AsIterMut, AsMutSlice, AsSlice, HasLen, Truncate,
     },
     executors::ExitKind,
     inputs::UsesInput,
@@ -116,12 +116,6 @@ pub trait MapObserver: HasLen + Named + Serialize + serde::de::DeserializeOwned
 
     /// Get the number of set entries with the specified indexes
     fn how_many_set(&self, indexes: &[usize]) -> usize;
-
-    /// Resize the inner map to be smaller (and thus faster to process)
-    /// It returns Some(old size) on success, None on failure
-    fn downsize_map(&mut self, _new_len: usize) -> Option<usize> {
-        None
-    }
 }
 
 /// A Simple iterator calling `MapObserver::get`
@@ -410,9 +404,21 @@ where
         }
         res
     }
+}
 
-    fn downsize_map(&mut self, new_len: usize) -> Option<usize> {
+impl<'a, T, const DIFFERENTIAL: bool> Truncate for StdMapObserver<'a, T, DIFFERENTIAL>
-        self.map.downsize(new_len)
+where
+    T: Bounded
+        + PartialEq
+        + Default
+        + Copy
+        + 'static
+        + Serialize
+        + serde::de::DeserializeOwned
+        + Debug,
+{
+    fn truncate(&mut self, new_len: usize) {
+        self.map.truncate(new_len);
     }
 }
 
@@ -1316,9 +1322,14 @@ where
     fn how_many_set(&self, indexes: &[usize]) -> usize {
         self.base.how_many_set(indexes)
     }
+}
 
-    fn downsize_map(&mut self, new_len: usize) -> Option<usize> {
+impl<M> Truncate for HitcountsMapObserver<M>
-        self.base.downsize_map(new_len)
+where
+    M: Named + Serialize + serde::de::DeserializeOwned + Truncate,
+{
+    fn truncate(&mut self, new_len: usize) {
+        self.base.truncate(new_len);
     }
 }
 
@@ -1539,9 +1550,14 @@ where
     fn how_many_set(&self, indexes: &[usize]) -> usize {
         self.base.how_many_set(indexes)
     }
+}
 
-    fn downsize_map(&mut self, new_len: usize) -> Option<usize> {
+impl<M> Truncate for HitcountsIterableMapObserver<M>
-        self.base.downsize_map(new_len)
+where
+    M: Named + Serialize + serde::de::DeserializeOwned + Truncate,
+{
+    fn truncate(&mut self, new_len: usize) {
+        self.base.truncate(new_len);
     }
 }