+ }
+ }
+
+ /*
+ * Do not terminate the current task, if proc_exec_switch_task did not
+ * switch the tasks, terminating the current task without the switch would
+ * result in loosing the SIGKILL status.
+ */
+ if (task_did_exec(current_task())) {
+ /* Terminate the current task, since exec will start in new task */
+ task_terminate_internal(current_task());
+ }
+
+ /* Release the thread ref returned by fork_create_child/fork1 */
+ if (imgp != NULL && imgp->ip_new_thread) {
+ /* wake up the new thread */
+ task_clear_return_wait(get_threadtask(imgp->ip_new_thread));
+ thread_deallocate(imgp->ip_new_thread);
+ imgp->ip_new_thread = NULL;
+ }
+
+ /* Release the ref returned by fork_create_child/fork1 */
+ if (new_task) {
+ task_deallocate(new_task);
+ new_task = NULL;
+ }
+
+ if (should_release_proc_ref) {
+ proc_rele(p);
+ }
+
+ if (bufp != NULL) {
+ FREE(bufp, M_TEMP);
+ }
+
+ if (inherit != NULL) {
+ ipc_importance_release(inherit);
+ }
+
+ return(error);
+}
+
+/*
+ * proc_exec_switch_task
+ *
+ * Parameters: p proc
+ * old_task task before exec
+ * new_task task after exec
+ * new_thread thread in new task
+ *
+ * Returns: proc.
+ *
+ * Note: The function will switch the task pointer of proc
+ * from old task to new task. The switch needs to happen
+ * after draining all proc refs and inside a proc translock.
+ * In the case of failure to switch the task, which might happen
+ * if the process received a SIGKILL or jetsam killed it, it will make
+ * sure that the new tasks terminates. User proc ref returned
+ * to caller.
+ *
+ * This function is called after point of no return, in the case
+ * failure to switch, it will terminate the new task and swallow the
+ * error and let the terminated process complete exec and die.
+ */
+proc_t
+proc_exec_switch_task(proc_t p, task_t old_task, task_t new_task, thread_t new_thread)
+{
+ int error = 0;
+ boolean_t task_active;
+ boolean_t proc_active;
+ boolean_t thread_active;
+ thread_t old_thread = current_thread();
+
+ /*
+ * Switch the task pointer of proc to new task.
+ * Before switching the task, wait for proc_refdrain.
+ * After the switch happens, the proc can disappear,
+ * take a ref before it disappears.
+ */
+ p = proc_refdrain_with_refwait(p, TRUE);
+ /* extra proc ref returned to the caller */
+
+ assert(get_threadtask(new_thread) == new_task);
+ task_active = task_is_active(new_task);
+
+ /* Take the proc_translock to change the task ptr */
+ proc_lock(p);
+ proc_active = !(p->p_lflag & P_LEXIT);
+
+ /* Check if the current thread is not aborted due to SIGKILL */
+ thread_active = thread_is_active(old_thread);
+
+ /*
+ * Do not switch the task if the new task or proc is already terminated
+ * as a result of error in exec past point of no return
+ */
+ if (proc_active && task_active && thread_active) {
+ error = proc_transstart(p, 1, 0);
+ if (error == 0) {
+ uthread_t new_uthread = get_bsdthread_info(new_thread);
+ uthread_t old_uthread = get_bsdthread_info(current_thread());
projects / apple / xnu.git / blobdiff