2 files changed, 98 insertions, 0 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index f183c1a7df17..90b273e7d8ec 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -946,6 +946,22 @@ bad_fork_free:
 	goto fork_out;
 }
 
+static inline int fork_traceflag (unsigned clone_flags)
+{
+	if (clone_flags & (CLONE_UNTRACED | CLONE_IDLETASK))
+		return 0;
+	else if (clone_flags & CLONE_VFORK) {
+		if (current->ptrace & PT_TRACE_VFORK)
+			return PTRACE_EVENT_VFORK;
+	} else if ((clone_flags & CSIGNAL) != SIGCHLD) {
+		if (current->ptrace & PT_TRACE_CLONE)
+			return PTRACE_EVENT_CLONE;
+	} else if (current->ptrace & PT_TRACE_FORK)
+		return PTRACE_EVENT_FORK;
+
+	return 0;
+}
+
 /*
  *  Ok, this is the main fork-routine.
  *
@@ -959,6 +975,13 @@ struct task_struct *do_fork(unsigned long clone_flags,
 			    int *user_tid)
 {
 	struct task_struct *p;
+	int trace = 0;
+
+	if (unlikely(current->ptrace)) {
+		trace = fork_traceflag (clone_flags);
+		if (trace)
+			clone_flags |= CLONE_PTRACE;
+	}
 
 	p = copy_process(clone_flags, stack_start, regs, stack_size, user_tid);
 	if (!IS_ERR(p)) {
@@ -974,6 +997,12 @@ struct task_struct *do_fork(unsigned long clone_flags,
 
 		wake_up_forked_process(p);		/* do this last */
 		++total_forks;
+
+		if (unlikely (trace)) {
+			current->ptrace_message = (unsigned long) p->pid;
+			ptrace_notify ((trace << 8) | SIGTRAP);
+		}
+
 		if (clone_flags & CLONE_VFORK)
 			wait_for_completion(&vfork);
 		else
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index cc7a76bb65b7..a2611977e53b 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -248,3 +248,72 @@ int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int
 	}
 	return copied;
 }
+
+static int ptrace_setoptions(struct task_struct *child, long data)
+{
+	if (data & PTRACE_O_TRACESYSGOOD)
+		child->ptrace |= PT_TRACESYSGOOD;
+	else
+		child->ptrace &= ~PT_TRACESYSGOOD;
+
+	if (data & PTRACE_O_TRACEFORK)
+		child->ptrace |= PT_TRACE_FORK;
+	else
+		child->ptrace &= ~PT_TRACE_FORK;
+
+	if (data & PTRACE_O_TRACEVFORK)
+		child->ptrace |= PT_TRACE_VFORK;
+	else
+		child->ptrace &= ~PT_TRACE_VFORK;
+
+	if (data & PTRACE_O_TRACECLONE)
+		child->ptrace |= PT_TRACE_CLONE;
+	else
+		child->ptrace &= ~PT_TRACE_CLONE;
+
+	if (data & PTRACE_O_TRACEEXEC)
+		child->ptrace |= PT_TRACE_EXEC;
+	else
+		child->ptrace &= ~PT_TRACE_EXEC;
+
+	if ((data & (PTRACE_O_TRACESYSGOOD | PTRACE_O_TRACEFORK
+		    | PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE
+		    | PTRACE_O_TRACEEXEC))
+	    != data)
+		return -EINVAL;
+
+	return 0;
+}
+
+int ptrace_request(struct task_struct *child, long request,
+		   long addr, long data)
+{
+	int ret = -EIO;
+
+	switch (request) {
+#ifdef PTRACE_OLDSETOPTIONS
+	case PTRACE_OLDSETOPTIONS:
+#endif
+	case PTRACE_SETOPTIONS:
+		ret = ptrace_setoptions(child, data);
+		break;
+	case PTRACE_GETEVENTMSG:
+		ret = put_user(child->ptrace_message, (unsigned long *) data);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+void ptrace_notify(int exit_code)
+{
+	BUG_ON (!(current->ptrace & PT_PTRACED));
+
+	/* Let the debugger run.  */
+	current->exit_code = exit_code;
+	set_current_state(TASK_STOPPED);
+	notify_parent(current, SIGCHLD);
+	schedule();
+}