BF: do not pass dangling symlinks to the server to be monitored

This is more of a workaround I guess than a "solution".  Ideally server
should be more clever and allow adding symlinks which eventually might
point to existing file.  But that is probably would be too much complication
for a rare use case.  User on the mailing list informed that then server
does not monitor even other files, thus as a quick workaround -- do not even add dangling links

client/jailreader.py

@@ -24,7 +24,7 @@ __author__ = "Cyril Jaquier"
 __copyright__ = "Copyright (c) 2004 Cyril Jaquier"
 __license__ = "GPL"
 
-import logging, re, glob
+import logging, re, glob, os.path
 
 from configreader import ConfigReader
 from filterreader import FilterReader
@@ -56,6 +56,22 @@ class JailReader(ConfigReader):
 	def isEnabled(self):
 		return self.__force_enable or self.__opts["enabled"]
 
+	@staticmethod
+	def _glob(path):
+		"""Given a path for glob return list of files to be passed to server.
+
+		Dangling symlinks are warned about and not returned
+		"""
+		pathList = []
+		for p in glob.glob(path):
+			if not os.path.exists(p):
+				logSys.warning("File %s doesn't even exist, thus cannot be monitored" % p)
+			elif not os.path.lexists(p):
+				logSys.warning("File %s is a dangling link, thus cannot be monitored" % p)
+			else:
+				pathList.append(p)
+		return pathList
+
 	def getOptions(self):
 		opts = [["bool", "enabled", "false"],
 				["string", "logpath", "/var/log/messages"],
@@ -118,7 +134,7 @@ class JailReader(ConfigReader):
 			if opt == "logpath":
 				found_files = 0
 				for path in self.__opts[opt].split("\n"):
-					pathList = glob.glob(path)
+					pathList = JailReader._glob(path)
 					if len(pathList) == 0:
 						logSys.error("No file(s) found for glob %s" % path)
 					for p in pathList:

testcases/clientreadertestcase.py

@@ -22,6 +22,7 @@ __copyright__ = "Copyright (c) 2004 Cyril Jaquier, 2011-2013 Yaroslav Halchenko"
 __license__ = "GPL"
 
 import os, tempfile, shutil, unittest
+
 from client.configreader import ConfigReader
 from client.jailreader import JailReader
 from client.jailsreader import JailsReader
@@ -117,6 +118,19 @@ class JailReaderTest(unittest.TestCase):
 		result = JailReader.splitAction(action)
 		self.assertEqual(expected, result)
 		
+	def testGlob(self):
+		d = tempfile.mkdtemp(prefix="f2b-temp")
+		# Generate few files
+		# regular file
+		open(os.path.join(d, 'f1'), 'w').close()
+		# dangling link
+		os.symlink('nonexisting', os.path.join(d, 'f2'))
+
+		# must be only f1
+		self.assertEqual(JailReader._glob(os.path.join(d, '*')), [os.path.join(d, 'f1')])
+		# since f2 is dangling -- empty list
+		self.assertEqual(JailReader._glob(os.path.join(d, 'f2')), [])
+
 class JailsReaderTest(unittest.TestCase):
 
 	def testProvidingBadBasedir(self):