X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=kernel%2Fptrace.c;h=d95a72c9279dc2e1110d31c0dadacc39b30b198f;hb=refs%2Fheads%2Fb2.6.16-omap1-h63xx;hp=5b8dd98a230e442c1ec46adc968acb60dfdb74ae;hpb=9b55cc6af61d3ff73ba746f798c5b765eec580b3;p=linux-2.6-omap-h63xx.git

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 5b8dd98a230..d95a72c9279 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -7,6 +7,7 @@
  * to continually duplicate across every architecture.
  */
 
+#include <linux/capability.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/errno.h>
@@ -71,8 +72,8 @@ void ptrace_untrace(task_t *child)
  */
 void __ptrace_unlink(task_t *child)
 {
-	if (!child->ptrace)
-		BUG();
+	BUG_ON(!child->ptrace);
+
 	child->ptrace = 0;
 	if (!list_empty(&child->ptrace_list)) {
 		list_del_init(&child->ptrace_list);
@@ -155,7 +156,7 @@ int ptrace_attach(struct task_struct *task)
 	retval = -EPERM;
 	if (task->pid <= 1)
 		goto bad;
-	if (task == current)
+	if (task->tgid == current->tgid)
 		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)
@@ -183,22 +184,27 @@ bad:
 	return retval;
 }
 
+void __ptrace_detach(struct task_struct *child, unsigned int data)
+{
+	child->exit_code = data;
+	/* .. re-parent .. */
+	__ptrace_unlink(child);
+	/* .. and wake it up. */
+	if (child->exit_state != EXIT_ZOMBIE)
+		wake_up_process(child);
+}
+
 int ptrace_detach(struct task_struct *child, unsigned int data)
 {
 	if (!valid_signal(data))
-		return	-EIO;
+		return -EIO;
 
 	/* Architecture-specific hardware disable .. */
 	ptrace_disable(child);
 
-	/* .. re-parent .. */
-	child->exit_code = data;
-
 	write_lock_irq(&tasklist_lock);
-	__ptrace_unlink(child);
-	/* .. and wake it up. */
-	if (child->exit_state != EXIT_ZOMBIE)
-		wake_up_process(child);
+	if (child->ptrace)
+		__ptrace_detach(child, data);
 	write_unlock_irq(&tasklist_lock);
 
 	return 0;
@@ -407,54 +413,62 @@ int ptrace_request(struct task_struct *child, long request,
 	return ret;
 }
 
-#ifndef __ARCH_SYS_PTRACE
-static int ptrace_get_task_struct(long request, long pid,
-		struct task_struct **childp)
+/**
+ * ptrace_traceme  --  helper for PTRACE_TRACEME
+ *
+ * Performs checks and sets PT_PTRACED.
+ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+ */
+int ptrace_traceme(void)
 {
-	struct task_struct *child;
 	int ret;
 
 	/*
-	 * Callers use child == NULL as an indication to exit early even
-	 * when the return value is 0, so make sure it is non-NULL here.
+	 * Are we already being traced?
+	 */
+	if (current->ptrace & PT_PTRACED)
+		return -EPERM;
+	ret = security_ptrace(current->parent, current);
+	if (ret)
+		return -EPERM;
+	/*
+	 * Set the ptrace bit in the process ptrace flags.
 	 */
-	*childp = NULL;
+	current->ptrace |= PT_PTRACED;
+	return 0;
+}
 
-	if (request == PTRACE_TRACEME) {
-		/*
-		 * Are we already being traced?
-		 */
-		if (current->ptrace & PT_PTRACED)
-			return -EPERM;
-		ret = security_ptrace(current->parent, current);
-		if (ret)
-			return -EPERM;
-		/*
-		 * Set the ptrace bit in the process ptrace flags.
-		 */
-		current->ptrace |= PT_PTRACED;
-		return 0;
-	}
+/**
+ * ptrace_get_task_struct  --  grab a task struct reference for ptrace
+ * @pid:       process id to grab a task_struct reference of
+ *
+ * This function is a helper for ptrace implementations.  It checks
+ * permissions and then grabs a task struct for use of the actual
+ * ptrace implementation.
+ *
+ * Returns the task_struct for @pid or an ERR_PTR() on failure.
+ */
+struct task_struct *ptrace_get_task_struct(pid_t pid)
+{
+	struct task_struct *child;
 
 	/*
-	 * You may not mess with init
+	 * Tracing init is not allowed.
 	 */
 	if (pid == 1)
-		return -EPERM;
+		return ERR_PTR(-EPERM);
 
-	ret = -ESRCH;
 	read_lock(&tasklist_lock);
 	child = find_task_by_pid(pid);
 	if (child)
 		get_task_struct(child);
 	read_unlock(&tasklist_lock);
 	if (!child)
-		return -ESRCH;
-
-	*childp = child;
-	return 0;
+		return ERR_PTR(-ESRCH);
+	return child;
 }
 
+#ifndef __ARCH_SYS_PTRACE
 asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 {
 	struct task_struct *child;
@@ -464,13 +478,20 @@ asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 	 * This lock_kernel fixes a subtle race with suid exec
 	 */
 	lock_kernel();
-	ret = ptrace_get_task_struct(request, pid, &child);
-	if (!child)
+	if (request == PTRACE_TRACEME) {
+		ret = ptrace_traceme();
 		goto out;
+	}
+
+	child = ptrace_get_task_struct(pid);
+	if (IS_ERR(child)) {
+		ret = PTR_ERR(child);
+		goto out;
+	}
 
 	if (request == PTRACE_ATTACH) {
 		ret = ptrace_attach(child);
-		goto out;
+		goto out_put_task_struct;
 	}
 
 	ret = ptrace_check_attach(child, request == PTRACE_KILL);