Fixes #36973 - Use dnf needs-restarting to collect tracer information (…

…#149)

* Fixes #36973 - Use dnf needs-restarting to collect tracer information

Co-Authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>

* Update src/katello/tracer/dnf.py

Co-authored-by: Ian Ballou <ianballou67@gmail.com>

---------

Co-authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>
Co-authored-by: Ian Ballou <ianballou67@gmail.com>

src/katello/tracer/SystemdDbus.py

@@ -0,0 +1,49 @@
+# SystemdUnit.py
+# Module for getting data from Systemd about Units
+
+# Copyright (C) 2017 Sean O'Keeffe
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions of
+# the GNU General Public License v.2, or (at your option) any later version.
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY expressed or implied, including the implied warranties of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+# Public License for more details.  You should have received a copy of the
+# GNU General Public License along with this program; if not, write to the
+# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+#
+
+import dbus
+
+class SystemdDbus(object):
+    def __init__(self):
+        self.__systemd = dbus.SystemBus().get_object('org.freedesktop.systemd1','/org/freedesktop/systemd1')
+        self.__manager = dbus.Interface(self.__systemd, dbus_interface='org.freedesktop.systemd1.Manager')
+
+    def unit_path_from_pid(self, pid):
+        try:
+            return self.__manager.GetUnitByPID(pid)
+        except dbus.exceptions.DBusException:
+            return False
+
+    def has_service_property_from_pid(self, pid, attr):
+        try:
+            unit = self.unit_path_from_pid(pid)
+            if not unit:
+                return False
+
+            proxy = dbus.SystemBus().get_object('org.freedesktop.systemd1', unit)
+            propty = proxy.Get('org.freedesktop.systemd1.Service', attr, dbus_interface='org.freedesktop.DBus.Properties')
+        except dbus.exceptions.DBusException:
+            return False
+        return bool(propty)
+
+    def get_unit_property_from_pid(self, pid, attr):
+        unit_path = self.unit_path_from_pid(pid)
+        if bool(unit_path):
+            proxy = dbus.SystemBus().get_object('org.freedesktop.systemd1', self.unit_path_from_pid(pid))
+            return proxy.Get('org.freedesktop.systemd1.Unit', attr, dbus_interface='org.freedesktop.DBus.Properties')
+        else:
+            return False

src/katello/tracer/__init__.py

@@ -6,35 +6,34 @@
 def collect_apps():
     raise NotImplementedError("Couldn't detect package manager. Failed to query affected apps!")
 
-try:
-    imp.find_module('apt')
-    from katello.tracer.deb import collect_apps
-except ImportError:
-    pass
-
+# RHEL based systems
 try:
     imp.find_module('dnf')
-    tracer = True
+    from katello.tracer.dnf import collect_apps
 except ImportError:
     try:
         imp.find_module('yum')
-        tracer = True
+        from tracer.query import Query
+        def collect_apps():
+            query = Query()
+            return query.affected_applications().get()
     except ImportError:
-        tracer = False
+        pass
 
-if tracer:
-    from tracer.query import Query
-    def collect_apps():
-        query = Query()
-        return query.affected_applications().get()
+# debian based systems
+try:
+    imp.find_module('apt')
+    from katello.tracer.deb import collect_apps
+except ImportError:
+    pass
 
+# SUSE based systems
 try:
     imp.find_module('zypp_plugin')
     from katello.tracer.zypper import collect_apps
 except ImportError:
     pass
 
-
 def upload_tracer_profile(queryfunc, plugin=None):
     uep = get_uep()
     consumer_id = lookup_consumer_id()

src/katello/tracer/dnf.py

@@ -0,0 +1,118 @@
+import os
+import re
+import subprocess
+import psutil
+from katello.tracer.SystemdDbus import SystemdDbus
+
+# these services need a reboot of the system
+STATIC_SERVICES = [
+    "systemd",
+    "dbus",
+]
+
+# these apps are ignored and no tracer will be added
+IGNORE_APPS = [
+    "sudo",
+    "su",
+    "(sd-pam)",
+]
+
+REBOOT_HELPER= 'You will have to reboot your computer'
+SESSION_HELPER = 'You will have to log out & log in again'
+
+class DnfTracerApp:
+    def __init__(self, name, helper, app_type):
+        self.name = name
+        self.helper = helper
+        self.type = app_type
+
+
+class Process:
+    def __init__(self, bus, pid):
+        self.bus = bus
+        self.pid = int(pid)
+        self.process = psutil.Process(self.pid)
+        self.name = self.detect_name()
+
+        # special handling for ssh sessions. Thanks to
+        # https://github.com/FrostyX/tracer/blob/ff8fc924fcbe2f638dd88b50549813dab2b8595b/tracer/resources/processes.py#L79
+        try:
+            if self.name == 'sshd':
+                exe = self.process.exe()
+                cmdline = self.process.cmdline()
+                if exe not in cmdline and len(cmdline) > 1:
+                    self.name = 'ssh-{0}-session'.format(re.split(' |@',' '.join(cmdline))[1])
+        except psutil.AccessDenied:
+            pass
+
+    def detect_name(self):
+        if self.pid and self.bus.unit_path_from_pid(self.pid):
+            if not self.bus.has_service_property_from_pid(self.pid, 'PAMName'):
+                unit_id = self.bus.get_unit_property_from_pid(self.pid, 'Id')
+                if unit_id and unit_id.endswith('.service'):
+                    return unit_id[:-8]
+        return self.process.name()
+
+    def is_session(self):
+        if self.name.startswith("ssh-") and self.name.endswith("-session"):
+            return True
+
+        terminal = self.process.terminal()
+        if terminal is not None:
+            parent = self.process.parent()
+            if parent is None or terminal != parent.terminal():
+                return True
+        return False
+
+    def is_reboot_required(self):
+        return self.name in STATIC_SERVICES
+
+
+def collect_services_state():
+    env = dict(os.environ, LANG='C')
+    process = subprocess.run(['dnf', 'needs-restarting'], env=env, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
+    if process.returncode != 0:
+        return []
+
+    lines = process.stdout.split('\n')
+    pids = [line.split(' : ')[0].strip() for line in lines if ' : ' in line]
+
+    apps = set()
+    bus = SystemdDbus()
+    added_services = []
+
+    for pid in pids:
+        p = Process(bus, pid)
+
+        if p.name in IGNORE_APPS:
+            continue
+
+        app_type = 'daemon'
+        helper = "systemctl restart " + p.name
+        if p.is_session():
+            app_type = 'session'
+            helper = SESSION_HELPER
+        if p.is_reboot_required():
+            app_type = 'static'
+            helper = REBOOT_HELPER
+
+        if p.name is not None and p.name not in added_services:
+            app = DnfTracerApp(p.name, helper, app_type)
+            apps.add(app)
+            added_services.append(p.name)
+    return list(apps)
+
+
+def collect_restart():
+    apps = []
+    process = subprocess.run(["dnf", "needs-restarting", "-r"], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+    if process.returncode == 1:
+        app = DnfTracerApp("kernel", REBOOT_HELPER, "static")
+        apps.append(app)
+    return apps
+
+
+def collect_apps(plugin=None):
+    apps = collect_services_state()
+    reboot = collect_restart()
+    return apps + reboot