Add pid-based data lookup function.

Two functions pid2task and pid2execname.

3 files changed, 29 insertions, 1 deletions

diff --git a/tapset/task.stp b/tapset/task.stp
index 07337156..f1a10b0a 100644
--- a/tapset/task.stp
+++ b/tapset/task.stp
@@ -63,6 +63,30 @@ function task_pid:long (task:long)
 }
 
 
+// Return the task of the given process id
+function pid2task:long (pid:long) %{ /* pure */
+    struct task_struct *t = NULL;
+    pid_t t_pid  = (pid_t)(long)THIS->pid;
+    rcu_read_lock();
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
+      t = find_task_by_vpid (t_pid);
+#else
+      t = find_task_by_pid (t_pid);
+#endif
+    rcu_read_unlock();
+    THIS->__retvalue = (long)t;
+    CATCH_DEREF_FAULT();
+%}
+
+// Return the name of the given process id
+function pid2execname:string (pid:long) { 
+    tsk = pid2task(pid)
+    if (tsk)
+	return task_execname(tsk)
+    return ""
+}
+
+
 // Return the thread id of the given task
 function task_tid:long (task:long)
 {
diff --git a/testsuite/buildok/task-embedded.stp b/testsuite/buildok/task-embedded.stp
index 4d1f5300..d35f3e0d 100755
--- a/testsuite/buildok/task-embedded.stp
+++ b/testsuite/buildok/task-embedded.stp
@@ -14,6 +14,8 @@ probe begin {
 		task_nice (0) +
 		task_cpu (0) +
 		task_open_file_handles (0) +
-		task_max_file_handles (0))
+		task_max_file_handles (0) +
+		pid2task(0))
 	print (task_execname (0))
+	print (pid2execname (0))
 }
diff --git a/testsuite/buildok/task_test.stp b/testsuite/buildok/task_test.stp
index c8da7da5..792f96ea 100755
--- a/testsuite/buildok/task_test.stp
+++ b/testsuite/buildok/task_test.stp
@@ -16,5 +16,7 @@ probe begin {
   log(sprint(task_cpu(c)))
   log(sprint(task_open_file_handles(c)))
   log(sprint(task_max_file_handles(c)))
+  log(sprint(pid2task(pid())))
+  log(sprint(pid2execname(pid())))
   exit()
 }