import os.path CONF_DIR = os.path.join(os.path.dirname(__file__), "../conf") def load_environment(): # Load settings from /etc/mailinabox.conf. return load_env_vars_from_file("/etc/mailinabox.conf") def load_env_vars_from_file(fn): # Load settings from a KEY=VALUE file. import collections env = collections.OrderedDict() for line in open(fn): env.setdefault(*line.strip().split("=", 1)) return env def save_environment(env): with open("/etc/mailinabox.conf", "w") as f: for k, v in env.items(): f.write("%s=%s\n" % (k, v)) def safe_domain_name(name): # Sanitize a domain name so it is safe to use as a file name on disk. import urllib.parse return urllib.parse.quote(name, safe='') def sort_domains(domain_names, env): # Put domain names in a nice sorted order. For web_update, PRIMARY_HOSTNAME # must appear first so it becomes the nginx default server. # First group PRIMARY_HOSTNAME and its subdomains, then parent domains of PRIMARY_HOSTNAME, then other domains. groups = ( [], [], [] ) for d in domain_names: if d == env['PRIMARY_HOSTNAME'] or d.endswith("." + env['PRIMARY_HOSTNAME']): groups[0].append(d) elif env['PRIMARY_HOSTNAME'].endswith("." + d): groups[1].append(d) else: groups[2].append(d) # Within each group, sort parent domains before subdomains and after that sort lexicographically. def sort_group(group): # Find the top-most domains. top_domains = sorted(d for d in group if len([s for s in group if d.endswith("." + s)]) == 0) ret = [] for d in top_domains: ret.append(d) ret.extend( sort_group([s for s in group if s.endswith("." + d)]) ) return ret groups = [sort_group(g) for g in groups] return groups[0] + groups[1] + groups[2] def exclusive_process(name): # Ensure that a process named `name` does not execute multiple # times concurrently. import os, sys, atexit pidfile = '/var/run/mailinabox-%s.pid' % name mypid = os.getpid() # Attempt to get a lock on ourself so that the concurrency check # itself is not executed in parallel. with open(__file__, 'r+') as flock: # Try to get a lock. This blocks until a lock is acquired. The # lock is held until the flock file is closed at the end of the # with block. os.lockf(flock.fileno(), os.F_LOCK, 0) # While we have a lock, look at the pid file. First attempt # to write our pid to a pidfile if no file already exists there. try: with open(pidfile, 'x') as f: # Successfully opened a new file. Since the file is new # there is no concurrent process. Write our pid. f.write(str(mypid)) atexit.register(clear_my_pid, pidfile) return except FileExistsError: # The pid file already exixts, but it may contain a stale # pid of a terminated process. with open(pidfile, 'r+') as f: # Read the pid in the file. existing_pid = None try: existing_pid = int(f.read().strip()) except ValueError: pass # No valid integer in the file. # Check if the pid in it is valid. if existing_pid: if is_pid_valid(existing_pid): print("Another %s is already running (pid %d)." % (name, existing_pid), file=sys.stderr) sys.exit(1) # Write our pid. f.seek(0) f.write(str(mypid)) f.truncate() atexit.register(clear_my_pid, pidfile) def clear_my_pid(pidfile): import os os.unlink(pidfile) def is_pid_valid(pid): """Checks whether a pid is a valid process ID of a currently running process.""" # adapted from http://stackoverflow.com/questions/568271/how-to-check-if-there-exists-a-process-with-a-given-pid import os, errno if pid <= 0: raise ValueError('Invalid PID.') try: os.kill(pid, 0) except OSError as err: if err.errno == errno.ESRCH: # No such process return False elif err.errno == errno.EPERM: # Not permitted to send signal return True else: # EINVAL raise else: return True def shell(method, cmd_args, env={}, capture_stderr=False, return_bytes=False, trap=False, input=None): # A safe way to execute processes. # Some processes like apt-get require being given a sane PATH. import subprocess env.update({ "PATH": "/sbin:/bin:/usr/sbin:/usr/bin" }) kwargs = { 'env': env, 'stderr': None if not capture_stderr else subprocess.STDOUT, } if method == "check_output" and input is not None: kwargs['input'] = input if not trap: ret = getattr(subprocess, method)(cmd_args, **kwargs) else: try: ret = getattr(subprocess, method)(cmd_args, **kwargs) code = 0 except subprocess.CalledProcessError as e: ret = e.output code = e.returncode if not return_bytes and isinstance(ret, bytes): ret = ret.decode("utf8") if not trap: return ret else: return code, ret def create_syslog_handler(): import logging.handlers handler = logging.handlers.SysLogHandler(address='/dev/log') handler.setLevel(logging.WARNING) return handler