Bug 1753758 - Add a crash method to ProcessToolsService r=gsvelto

Differential Revision: https://phabricator.services.mozilla.com/D137907

toolkit/components/processtools/nsIProcessToolsService.idl

@@ -33,6 +33,14 @@ interface nsIProcessToolsService: nsISupports {
      */
     void kill(in unsigned long long pid);
 
+    /**
+     * Crash a process running on this system. Generates a SIGABRT on Linux and
+     * macOS, and a STATUS_ILLEGAL_INSTRUCTION on Windows.
+     *
+     * Does cause a crash report to be generated.
+     */
+    void crash(in unsigned long long pid);
+
     /**
      * The pid for the current process.
      */

toolkit/components/processtools/src/lib.rs

@@ -25,6 +25,19 @@ pub unsafe extern "C" fn new_process_tools_service(result: *mut *const nsIProces
     RefPtr::new(service.coerce::<nsIProcessToolsService>()).forget(&mut *result);
 }
 
+#[cfg(target_os = "windows")]
+use std::ffi::c_void;
+
+// We want to generate an exception that can be caught by the exception handler
+// when injecting in a remote process, STATUS_ACCESS_VIOLATION seems not to do,
+// it but the following code generates a STATUS_ILLEGAL_INSTRUCTION that seems
+// to do the trick
+#[cfg(target_os = "windows")]
+pub unsafe extern "system" fn crash_illegal_instruction(_arg: *mut c_void) -> u32 {
+    std::ptr::null_mut::<u32>().write(1);
+    0
+}
+
 // Implementation note:
 //
 // We're following the strategy employed by the `kvstore`.
@@ -87,6 +100,65 @@ impl ProcessToolsService {
         }
     }
 
+    // Method `crash`
+
+    xpcom_method!(
+        crash => Crash(id: u64)
+    );
+
+    #[cfg(target_os = "windows")]
+    pub fn crash(&self, pid: u64) -> Result<(), nsresult> {
+        let target_proc = unsafe {
+            winapi::um::processthreadsapi::OpenProcess(
+                /* dwDesiredAccess */
+                winapi::um::winnt::PROCESS_VM_OPERATION
+                    | winapi::um::winnt::PROCESS_CREATE_THREAD
+                    | winapi::um::winnt::PROCESS_QUERY_INFORMATION,
+                /* bInheritHandle */ 0,
+                /* dwProcessId */ pid.try_into().unwrap(),
+            )
+        };
+        if target_proc.is_null() {
+            // Could not open process.
+            return Err(NS_ERROR_NOT_AVAILABLE);
+        }
+
+        let new_thread = unsafe {
+            winapi::um::processthreadsapi::CreateRemoteThread(
+                /* hProcess */ target_proc,
+                /* lpThreadAttributes */ std::ptr::null_mut(),
+                /* dwStackSize */ 0,
+                /* lpStartAddress */ Some(crash_illegal_instruction),
+                /* lpParameter */ std::ptr::null_mut(),
+                /* dwCreationFlags */ 0,
+                /* lpThreadId */ std::ptr::null_mut(),
+            )
+        };
+
+        // Close handle regardless of success.
+        let _ = unsafe {
+            winapi::um::synchapi::WaitForSingleObject(new_thread, winapi::um::winbase::INFINITE);
+            winapi::um::handleapi::CloseHandle(new_thread);
+            winapi::um::handleapi::CloseHandle(target_proc);
+        };
+
+        if new_thread.is_null() {
+            return Err(NS_ERROR_FAILURE);
+        }
+        Ok(())
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    pub fn crash(&self, pid: u64) -> Result<(), nsresult> {
+        let pid = pid.try_into().or(Err(NS_ERROR_FAILURE))?;
+        let result = unsafe { libc::kill(pid, libc::SIGABRT) };
+        if result == 0 {
+            Ok(())
+        } else {
+            Err(NS_ERROR_FAILURE)
+        }
+    }
+
     // Attribute `pid`
 
     xpcom_method!(