1 files changed, 177 insertions, 0 deletions
diff --git a/toolkit/components/processtools/src/lib.rs b/toolkit/components/processtools/src/lib.rs
new file mode 100644
index 0000000000..a84aa9ef62
--- /dev/null
+++ b/toolkit/components/processtools/src/lib.rs
@@ -0,0 +1,177 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[cfg(not(target_os = "windows"))]
+extern crate libc;
+#[cfg(target_os = "windows")]
+extern crate winapi;
+
+extern crate nserror;
+extern crate xpcom;
+
+use std::convert::TryInto;
+
+use nserror::{nsresult, NS_ERROR_FAILURE, NS_OK};
+use xpcom::{interfaces::nsIProcessToolsService, xpcom, xpcom_method, RefPtr};
+
+// Separate this `use` to avoid build-breaking warnings.
+#[cfg(target_os = "windows")]
+use nserror::NS_ERROR_NOT_AVAILABLE;
+
+#[no_mangle]
+pub unsafe extern "C" fn new_process_tools_service(result: *mut *const nsIProcessToolsService) {
+    let service: RefPtr<ProcessToolsService> = ProcessToolsService::new();
+    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`.
+// See https://searchfox.org/mozilla-central/rev/a87a1c3b543475276e6d57a7a80cb02f3e42b6ed/toolkit/components/kvstore/src/lib.rs#78
+
+#[xpcom(implement(nsIProcessToolsService), atomic)]
+pub struct ProcessToolsService {}
+
+impl ProcessToolsService {
+    pub fn new() -> RefPtr<ProcessToolsService> {
+        ProcessToolsService::allocate(InitProcessToolsService {})
+    }
+
+    // Method `kill`.
+
+    xpcom_method!(
+        kill => Kill(id: u64)
+    );
+
+    #[cfg(target_os = "windows")]
+    pub fn kill(&self, pid: u64) -> Result<(), nsresult> {
+        let handle = unsafe {
+            winapi::um::processthreadsapi::OpenProcess(
+                /* dwDesiredAccess */
+                winapi::um::winnt::PROCESS_TERMINATE | winapi::um::winnt::SYNCHRONIZE,
+                /* bInheritHandle */ 0,
+                /* dwProcessId */ pid.try_into().unwrap(),
+            )
+        };
+        if handle.is_null() {
+            // Could not open process.
+            return Err(NS_ERROR_NOT_AVAILABLE);
+        }
+
+        let result = unsafe {
+            winapi::um::processthreadsapi::TerminateProcess(
+                /* hProcess */ handle, /* uExitCode */ 0,
+            )
+        };
+
+        // Close handle regardless of success.
+        let _ = unsafe { winapi::um::handleapi::CloseHandle(handle) };
+
+        if result == 0 {
+            return Err(NS_ERROR_FAILURE);
+        }
+        Ok(())
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    pub fn kill(&self, pid: u64) -> Result<(), nsresult> {
+        let pid = pid.try_into().or(Err(NS_ERROR_FAILURE))?;
+        let result = unsafe { libc::kill(pid, libc::SIGKILL) };
+        if result == 0 {
+            Ok(())
+        } else {
+            Err(NS_ERROR_FAILURE)
+        }
+    }
+
+    // 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!(
+        get_pid => GetPid() -> u64
+    );
+
+    #[cfg(not(target_os = "windows"))]
+    pub fn get_pid(&self) -> Result<u64, nsresult> {
+        let pid = unsafe { libc::getpid() } as u64;
+        Ok(pid)
+    }
+
+    #[cfg(target_os = "windows")]
+    pub fn get_pid(&self) -> Result<u64, nsresult> {
+        let pid = unsafe { winapi::um::processthreadsapi::GetCurrentProcessId() } as u64;
+        Ok(pid)
+    }
+}