require logfile only for aa-logprof and aa-genprof

Make sure most tools (for example aa-complain) don't error out if
no logfile can be found. (For obvious reasons, aa-logprof and
aa-genprof will still require a logfile ;-)

This is done by moving code from the global area in aa.py to the new
function set_logfile(), which is called by aa-logprof and aa-genprof.

While on it,
- rename apparmor.filename to apparmor.logfile
- move the error handling for user-specified logfile from aa-genprof
  and aa-logprof to aa.py set_logfile()

Note: I'd have prefered to hand over the logfile as parameter to
do_logprof_pass(), but that would break last_audit_entry_time() in
aa-genprof which requires the log filename before do_logprof_pass()
is called.

References: https://bugs.launchpad.net/apparmor/+bug/1423702


Acked-by: Seth Arnold <seth.arnold@canonical.com>

utils/aa-genprof

@@ -41,7 +41,7 @@ def sysctl_write(path, value):
         f_out.write(str(value))
 
 def last_audit_entry_time():
-    out = subprocess.check_output(['tail', '-1', apparmor.filename])
+    out = subprocess.check_output(['tail', '-1', apparmor.logfile])
     logmark = None
     out = out.decode('ascii')
     if re.search('^.*msg\=audit\((\d+\.\d+\:\d+).*\).*$', out):
@@ -61,16 +61,8 @@ args = parser.parse_args()
 
 profiling = args.program
 profiledir = args.dir
-filename = args.file
 
-
-if filename:
-    if not os.path.exists(filename):
-        raise apparmor.AppArmorException(_('The logfile %s does not exist. Please check the path') % filename)
-    elif os.path.isdir(filename):
-        raise apparmor.AppArmorException(_('%s is a directory. Please specify a file as logfile') % filename)
-    else:
-        apparmor.filename = filename
+apparmor.set_logfile(args.file)
 
 aa_mountpoint = apparmor.check_for_apparmor()
 if not aa_mountpoint:

utils/aa-logprof

@@ -28,17 +28,9 @@ parser.add_argument('-m', '--mark', type=str, help=_('mark in the log to start p
 args = parser.parse_args()
 
 profiledir = args.dir
-filename = args.file
 logmark = args.mark or ''
 
-
-if filename:
-    if not os.path.exists(filename):
-        raise apparmor.AppArmorException(_('The logfile %s does not exist. Please check the path') % filename)
-    elif os.path.isdir(filename):
-        raise apparmor.AppArmorException(_('%s is a directory. Please specify a file as logfile') % filename)
-    else:
-        apparmor.filename = filename
+apparmor.set_logfile(args.file)
 
 aa_mountpoint = apparmor.check_for_apparmor()
 if not aa_mountpoint:

utils/apparmor/aa.py

@@ -72,7 +72,7 @@ unimplemented_warning = False
 sev_db = None
 # The file to read log messages from
 ### Was our
-filename = None
+logfile = None
 
 cfg = None
 repo_cfg = None
@@ -2233,6 +2233,24 @@ def match_net_includes(profile, family, nettype):
 
     return newincludes
 
+def set_logfile(filename):
+    ''' set logfile to a) the specified filename or b) if not given, the first existing logfile from logprof.conf'''
+
+    global logfile
+
+    if filename:
+        logfile = filename
+    else:
+        logfile = conf.find_first_file(cfg['settings']['logfiles']) or '/var/log/syslog'
+
+    if not os.path.exists(logfile):
+        if filename:
+            raise AppArmorException(_('The logfile %s does not exist. Please check the path') % logfile)
+        else:
+            raise AppArmorException('Can\'t find system log "%s".' % (logfile))
+    elif os.path.isdir(logfile):
+        raise AppArmorException(_('%s is a directory. Please specify a file as logfile') % logfile)
+
 def do_logprof_pass(logmark='', passno=0, pid=pid):
     # set up variables for this pass
 #    t = hasher()
@@ -2250,7 +2268,7 @@ def do_logprof_pass(logmark='', passno=0, pid=pid):
 #    skip = hasher()  # XXX global?
 #    filelist = hasher()
 
-    aaui.UI_Info(_('Reading log entries from %s.') % filename)
+    aaui.UI_Info(_('Reading log entries from %s.') % logfile)
 
     if not passno:
         aaui.UI_Info(_('Updating AppArmor profiles in %s.') % profile_dir)
@@ -2264,7 +2282,8 @@ def do_logprof_pass(logmark='', passno=0, pid=pid):
     ##    repo_cfg = read_config('repository.conf')
     ##    if not repo_cfg['repository'].get('enabled', False) or repo_cfg['repository]['enabled'] not in ['yes', 'no']:
     ##    UI_ask_to_enable_repo()
-    log_reader = apparmor.logparser.ReadLog(pid, filename, existing_profiles, profile_dir, log)
+
+    log_reader = apparmor.logparser.ReadLog(pid, logfile, existing_profiles, profile_dir, log)
     log = log_reader.read_log(logmark)
     #read_log(logmark)
 
@@ -4572,10 +4591,6 @@ parser = conf.find_first_file(cfg['settings']['parser']) or '/sbin/apparmor_pars
 if not os.path.isfile(parser) or not os.access(parser, os.EX_OK):
     raise AppArmorException('Can\'t find apparmor_parser')
 
-filename = conf.find_first_file(cfg['settings']['logfiles']) or '/var/log/syslog'
-if not os.path.isfile(filename):
-    raise AppArmorException('Can\'t find system log "%s".' % (filename))
-
 ldd = conf.find_first_file(cfg['settings']['ldd']) or '/usr/bin/ldd'
 if not os.path.isfile(ldd) or not os.access(ldd, os.EX_OK):
     raise AppArmorException('Can\'t find ldd')