[policies] run PackageManager query_command under timeout

PackageManager query commands may block due to file system locks
or problems with the package database. Run the query command with
a timeout of 30s and exit if the timeout expires.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Signed-off-by: Bryn M. Reeves <bmr@redhat.com>

---
Changes from v3:
	Add default timeout instead of making it configurable
	Add print function instead of error()

Changes from v2:
	Introduce timeout in shell_out wrapper

Changes from v1:
	Addressed issues of the maintainer
	Introduce timeout instead of relying on yum.

3 files changed, 13 insertions, 4 deletions

diff --git a/sos/policies/__init__.py b/sos/policies/__init__.py
index 9fcbd552..34a2f6a2 100644
--- a/sos/policies/__init__.py
+++ b/sos/policies/__init__.py
@@ -56,6 +56,7 @@ class PackageManager(object):
     """
 
     query_command = None
+    timeout = 30
 
     def __init__(self, query_command=None):
         self.packages = {}
@@ -92,7 +93,7 @@ class PackageManager(object):
                           version': 'major.minor.version'}}
         """
         if self.query_command:
-            pkg_list = shell_out(self.query_command).splitlines()
+            pkg_list = shell_out(self.query_command, self.timeout).splitlines()
             for pkg in pkg_list:
                 if '|' not in pkg:
                     continue
diff --git a/sos/policies/redhat.py b/sos/policies/redhat.py
index 22192463..38510d93 100644
--- a/sos/policies/redhat.py
+++ b/sos/policies/redhat.py
@@ -15,6 +15,7 @@
 # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
 # This enables the use of with syntax in python 2.5 (e.g. jython)
+from __future__ import print_function
 import os
 import sys
 
@@ -46,8 +47,15 @@ class RedHatPolicy(LinuxPolicy):
             'rpm -qa --queryformat "%{NAME}|%{VERSION}\\n"')
         self.valid_subclasses = [RedHatPlugin]
 
+        pkgs = self.package_manager.all_pkgs()
+
+        # If rpm query timed out after timeout duration exit
+        if not pkgs:
+            print("Could not obtain installed package list", file=sys.stderr)
+            sys.exit(1)
+
         # handle PATH for UsrMove
-        if self.package_manager.all_pkgs()['filesystem']['version'][0] == '3':
+        if pkgs['filesystem']['version'][0] == '3':
             self.PATH = "/usr/sbin:/usr/bin:/root/bin"
         else:
             self.PATH = "/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"
diff --git a/sos/utilities.py b/sos/utilities.py
index 51909c64..2638ce4a 100644
--- a/sos/utilities.py
+++ b/sos/utilities.py
@@ -180,11 +180,11 @@ def import_module(module_fqname, superclasses=None):
     return modules
 
 
-def shell_out(cmd, runat=None):
+def shell_out(cmd, timeout=30, runat=None):
     """Shell out to an external command and return the output or the empty
     string in case of error.
     """
-    return sos_get_command_output(cmd, runat=runat)['output']
+    return sos_get_command_output(cmd, timeout=timeout, runat=runat)['output']
 
 
 class ImporterHelper(object):