Add Result and Error on interceptor attach and attach_instruction

examples/gum/hook_instruction/src/lib.rs

@@ -22,5 +22,5 @@ fn init() {
     let mut interceptor = Interceptor::obtain(&GUM);
     let open = Module::find_export_by_name(None, "open").unwrap();
     let mut listener = OpenProbeListener;
-    interceptor.attach_instruction(open, &mut listener);
+    interceptor.attach_instruction(open, &mut listener).unwrap();
 }

examples/gum/open/src/lib.rs

@@ -40,5 +40,5 @@ extern "C" fn example_agent_main(_user_data: *const c_void, resident: *mut c_int
     }
 
     let open = Module::find_export_by_name(None, "open").unwrap();
-    interceptor.attach(open, &mut listener);
+    interceptor.attach(open, &mut listener).unwrap();
 }

frida-gum/src/error.rs

@@ -13,6 +13,9 @@ pub enum Error {
     /// Function is already replaced during Interceptor operation
     InterceptorAlreadyReplaced,
 
+    /// Function is already attached during Interceptor operation
+    InterceptorAlreadyAttached,
+
     /// Policy violation
     PolicyViolation,
 
@@ -30,6 +33,7 @@ impl fmt::Display for Error {
         match self {
             Error::InterceptorBadSignature => write!(fmt, "Bad signature"),
             Error::InterceptorAlreadyReplaced => write!(fmt, "Function already replaced"),
+            Error::InterceptorAlreadyAttached => write!(fmt, "Function already attached"),
             Error::PolicyViolation => write!(fmt, "Policy violation"),
             Error::InterceptorError => write!(fmt, "Interceptor error"),
             Error::MemoryAccessError => write!(fmt, "Memory access error"),

frida-gum/src/interceptor.rs

@@ -52,12 +52,22 @@ impl<'a> Interceptor<'a> {
         &mut self,
         f: NativePointer,
         listener: &mut I,
-    ) -> NativePointer {
+    ) -> Result<NativePointer> {
         let listener = invocation_listener_transform(listener);
-        unsafe {
+        match unsafe {
             gum_sys::gum_interceptor_attach(self.interceptor, f.0, listener, ptr::null_mut())
-        };
-        NativePointer(listener as *mut c_void)
+        } {
+            gum_sys::GumAttachReturn_GUM_ATTACH_OK => Ok(NativePointer(listener as *mut c_void)),
+            gum_sys::GumAttachReturn_GUM_ATTACH_WRONG_SIGNATURE => {
+                Err(Error::InterceptorBadSignature)
+            }
+            gum_sys::GumAttachReturn_GUM_ATTACH_ALREADY_ATTACHED => {
+                Err(Error::InterceptorAlreadyAttached)
+            }
+            gum_sys::GumAttachReturn_GUM_ATTACH_POLICY_VIOLATION => Err(Error::PolicyViolation),
+            gum_sys::GumAttachReturn_GUM_ATTACH_WRONG_TYPE => Err(Error::WrongType),
+            _ => Err(Error::InterceptorError),
+        }
     }
 
     /// Attach a listener to an instruction address.
@@ -71,12 +81,22 @@ impl<'a> Interceptor<'a> {
         &mut self,
         instr: NativePointer,
         listener: &mut I,
-    ) -> NativePointer {
+    ) -> Result<NativePointer> {
         let listener = probe_listener_transform(listener);
-        unsafe {
+        match unsafe {
             gum_sys::gum_interceptor_attach(self.interceptor, instr.0, listener, ptr::null_mut())
-        };
-        NativePointer(listener as *mut c_void)
+        } {
+            gum_sys::GumAttachReturn_GUM_ATTACH_OK => Ok(NativePointer(listener as *mut c_void)),
+            gum_sys::GumAttachReturn_GUM_ATTACH_WRONG_SIGNATURE => {
+                Err(Error::InterceptorBadSignature)
+            }
+            gum_sys::GumAttachReturn_GUM_ATTACH_ALREADY_ATTACHED => {
+                Err(Error::InterceptorAlreadyAttached)
+            }
+            gum_sys::GumAttachReturn_GUM_ATTACH_POLICY_VIOLATION => Err(Error::PolicyViolation),
+            gum_sys::GumAttachReturn_GUM_ATTACH_WRONG_TYPE => Err(Error::WrongType),
+            _ => Err(Error::InterceptorError),
+        }
     }
 
     /// Detach an attached listener.