#!/usr/bin/python
import os
import dbus
import pwd
import sys

# Urgencies
URGENCY_LOW = 0
URGENCY_NORMAL = 1
URGENCY_CRITICAL = 2
	
def setup():
	try:
		# smartd should have these
		global smartd_device 
		smartd_device = os.environ['SMARTD_DEVICE']
		global smartd_devicestring 
		smartd_devicestring = os.environ['SMARTD_DEVICESTRING']
		global smartd_failtype 
		smartd_failtype = os.environ['SMARTD_FAILTYPE']
	except:
		exit(1)
	
# What users we want to notify
def testuser(param):
	# The default user's id is 1000 and the next created ones increment from there
	return ((param[2]>=1000) and (param[2])<=10000)

# The uid is at index #2
def getuids(pwd):
	return pwd[2]
	
# Returns the list of "real" users of the computer
def getusers():
	users = pwd.getpwall()
	filtered = filter(testuser,users)
	return map(getuids,filtered)

# We are forced to fork for this activity once per user you want to notify.
def notifyusers(message,urg):
	users = getusers()
	for user in users:
		pid = os.fork()
		if pid:
			os.waitpid(pid, 0)
		else:
			#setuid
			os.setuid(user)
			# Notify this user
			notify(message,urg)
			sys.exit(0)

# The notification itself
def notify (message,urg):
	# D-bus settings
	BUS_NAME = 'org.freedesktop.Notifications'
	OBJ_PATH = '/org/freedesktop/Notifications'
	IFACE_NAME = 'org.freedesktop.Notifications'
	bus = dbus.SessionBus()
	notify_obj = bus.get_object(BUS_NAME,OBJ_PATH)
	notifications = dbus.Interface(notify_obj,IFACE_NAME)
	#  Explained further at http://www.galago-project.org/specs/notification/0.9/index.html
	hints = {"urgency":urg}
	notifications.Notify('Hard drive health monitoring agent',0,'/usr/share/icons/Tango/scalable/status/important.svg','Potential hard disk failure!',message,[],hints,0)	
			
# Returns error message and priority in list
def geterrordetails(failtype):
	msg = {
		"EmailTest": ["This is an email test message.",URGENCY_LOW],
		"Health": ["The SMART health status indicates imminent failure.",URGENCY_CRITICAL],
		"Usage": ["A usage Attribute has failed.",URGENCY_NORMAL],
		"SelfTest": ["The number of self-test failures has increased.",URGENCY_NORMAL],
		"ErrorCount": ["The number of errors in the ATA error log has increased.",URGENCY_NORMAL],
		"CurrentPendingSector": ["One of more disk sectors could not be read and are marked to be reallocated (replaced with spare sectors).",URGENCY_NORMAL],
		"OfflineUncorrectableSector": ["During off-line testing, or self-testing, one or more disk sectors could not be read.",URGENCY_NORMAL],
		"FailedHealthCheck": ["The SMART health status command failed.",URGENCY_NORMAL],
		"FailedReadSmartData": ["The command to read SMART Attribute data failed.",URGENCY_NORMAL],
		"FailedReadSmartErrorLog": ["The command to read the SMART error log failed.",URGENCY_NORMAL],
		"FailedReadSmartSelfTestLog": ["The command to read the SMART self-test log failed.",URGENCY_NORMAL],
		"FailedOpenDevice": ["The open() command to the device failed.",URGENCY_NORMAL]}
	i = msg.get(failtype,["Internal error in monitoring agent.",URGENCY_LOW])
	return i[0],i[1]

# The main logic
def main():
	setup()
	msg,urgency = geterrordetails(smartd_failtype)
	message = "The hard drive SMART monitoring agent has detected a potential problem with your hard disc "+smartd_devicestring+". The message given was: "+msg
	notifyusers(message,urgency)

main()