ptrace.c

/*
 * linux/kernel/ptrace.c
 *
 * (C) Copyright 1999 Linus Torvalds
 *
 * Common interfaces for "ptrace()" which we do not want
 * to continually duplicate across every architecture.
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>

/*
 * ptrace a task: make the debugger its new parent and
 * move it to the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_link(task_t *child, task_t *new_parent)
{
	if (!list_empty(&child->ptrace_list))
		BUG();
	if (child->parent == new_parent)
		return;
	list_add(&child->ptrace_list, &child->parent->ptrace_children);
	REMOVE_LINKS(child);
	child->parent = new_parent;
	SET_LINKS(child);
}
 
/*
 * Turn a tracing stop into a normal stop now, since with no tracer there
 * would be no way to wake it up with SIGCONT or SIGKILL.  If there was a
 * signal sent that would resume the child, but didn't because it was in
 * TASK_TRACED, resume it now.
 * Requires that irqs be disabled.
 */
void ptrace_untrace(task_t *child)
{
	spin_lock(&child->sighand->siglock);
	if (child->state == TASK_TRACED) {
		if (child->signal->flags & SIGNAL_STOP_STOPPED) {
			child->state = TASK_STOPPED;
		} else {
			signal_wake_up(child, 1);
		}
	}
	spin_unlock(&child->sighand->siglock);
}

/*
 * unptrace a task: move it back to its original parent and
 * remove it from the ptrace list.
 *
 * Must be called with the tasklist lock write-held.
 */
void __ptrace_unlink(task_t *child)
{
	if (!child->ptrace)