From 8f3dc05f97889bdd607688fed3167cdbd4bcf937 Mon Sep 17 00:00:00 2001
From: Elieva Pignat <Elieva.Pignat@arm.com>
Date: Tue, 27 Feb 2018 12:19:36 +0000
Subject: [PATCH] cgroups.py: Add filters for the tasks() function

The tasks() function allows to get the tasks that are in a cgroup.
Filters for the tasks TID, name and cmdline have been added to the
parameters of the function such that it is possible to select the tasks
that match these patterns.

Signed-off-by: Elieva Pignat <Elieva.Pignat@arm.com>
---
 devlib/module/cgroups.py | 52 ++++++++++++++++++++++++++++++++--------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/devlib/module/cgroups.py b/devlib/module/cgroups.py
index 8935325..b77d7ba 100644
--- a/devlib/module/cgroups.py
+++ b/devlib/module/cgroups.py
@@ -14,6 +14,7 @@
 #
 # pylint: disable=attribute-defined-outside-init
 import logging
+import re
 from collections import namedtuple
 
 from devlib.module import Module
@@ -168,7 +169,37 @@ class Controller(object):
             if cgroup != dest:
                 self.move_tasks(cgroup, dest, grep_filters)
 
-    def tasks(self, cgroup):
+    def tasks(self, cgroup,
+              filter_tid='',
+              filter_tname='',
+              filter_tcmdline=''):
+        """
+        Report the tasks that are included in a cgroup. The tasks can be
+        filtered by their tid, tname or tcmdline if filter_tid, filter_tname or
+        filter_tcmdline are defined respectively. In this case, the reported
+        tasks are the ones in the cgroup that match these patterns.
+
+        Example of tasks format:
+        TID,tname,tcmdline
+        903,cameraserver,/system/bin/cameraserver
+
+        :params filter_tid: regexp pattern to filter by TID
+        :type filter_tid: str
+
+        :params filter_tname: regexp pattern to filter by tname
+        :type filter_tname: str
+
+        :params filter_tcmdline: regexp pattern to filter by tcmdline
+        :type filter_tcmdline: str
+
+        :returns: a dictionary in the form: {tid:(tname, tcmdline)}
+        """
+        if not isinstance(filter_tid, str):
+            raise TypeError('filter_tid should be a str')
+        if not isinstance(filter_tname, str):
+            raise TypeError('filter_tname should be a str')
+        if not isinstance(filter_tcmdline, str):
+            raise TypeError('filter_tcmdline should be a str')
         try:
             cg = self._cgroups[cgroup]
         except KeyError as e:
@@ -179,15 +210,16 @@ class Controller(object):
         entries = output.splitlines()
         tasks = {}
         for task in entries:
-            tid = task.split(',')[0]
-            try:
-                tname = task.split(',')[1]
-            except: continue
-            try:
-                tcmdline = task.split(',')[2]
-            except:
-                tcmdline = ''
-            tasks[int(tid)] = (tname, tcmdline)
+            tid_str, tname, tcmdline = task.split(',', 2)
+
+            if not re.search(filter_tid, tid_str):
+                continue
+            if not re.search(filter_tname, tname):
+                continue
+            if not re.search(filter_tcmdline, tcmdline):
+                continue
+
+            tasks[int(tid_str)] = (tname, tcmdline)
         return tasks
 
     def tasks_count(self, cgroup):