- lock_kernel();
-
- if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED) {
- rval = -EPERM;
- goto out;
- }
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
- rval = 0;
- goto out;
- }
- rval = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
-
- rval = -EPERM;
- if (pid == 1) /* you may not mess with init */
- goto out_tsk;
-
- if (request == PTRACE_ATTACH) {
- rval = ptrace_attach(child);
- goto out_tsk;
- }
- rval = -ESRCH;
- if (!(child->ptrace & PT_PTRACED))
- goto out_tsk;
- if (child->state != TASK_STOPPED) {
- if (request != PTRACE_KILL)
- goto out_tsk;
- }
- if (child->parent != current)
- goto out_tsk;
-