import os.path # DO NOT import non-standard modules. This module is imported by # migrate.py which runs on fresh machines before anything is installed # besides Python. # THE ENVIRONMENT FILE AT /etc/mailinabox.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)) # THE SETTINGS FILE AT STORAGE_ROOT/settings.yaml. def write_settings(config, env): import rtyaml fn = os.path.join(env['STORAGE_ROOT'], 'settings.yaml') with open(fn, "w") as f: f.write(rtyaml.dump(config)) def load_settings(env): import rtyaml fn = os.path.join(env['STORAGE_ROOT'], 'settings.yaml') try: config = rtyaml.load(open(fn, "r")) if not isinstance(config, dict): raise ValueError() # caught below return config except: return { } # UTILITIES 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. # The nice order will group domain names by DNS zone, i.e. the top-most # domain name that we serve that ecompasses a set of subdomains. Map # each of the domain names to the zone that contains them. Walk the domains # from shortest to longest since zones are always shorter than their # subdomains. zones = { } for domain in sorted(domain_names, key=lambda d : len(d)): for z in zones.values(): if domain.endswith("." + z): # We found a parent domain already in the list. zones[domain] = z break else: # 'break' did not occur: there is no parent domain, so it is its # own zone. zones[domain] = domain # Sort the zones. zone_domains = sorted(zones.values(), key = lambda d : ( # PRIMARY_HOSTNAME or the zone that contains it is always first. not (d == env['PRIMARY_HOSTNAME'] or env['PRIMARY_HOSTNAME'].endswith("." + d)), # Then just dumb lexicographically. d, )) # Now sort the domain names that fall within each zone. domain_names = sorted(domain_names, key = lambda d : ( # First by zone. zone_domains.index(zones[d]), # PRIMARY_HOSTNAME is always first within the zone that contains it. d != env['PRIMARY_HOSTNAME'], # Followed by any of its subdomains. not d.endswith("." + env['PRIMARY_HOSTNAME']), # Then in right-to-left lexicographic order of the .-separated parts of the name. list(reversed(d.split("."))), )) return domain_names def sort_email_addresses(email_addresses, env): email_addresses = set(email_addresses) domains = set(email.split("@", 1)[1] for email in email_addresses if "@" in email) ret = [] for domain in sort_domains(domains, env): domain_emails = set(email for email in email_addresses if email.endswith("@" + domain)) ret.extend(sorted(domain_emails)) email_addresses -= domain_emails ret.extend(sorted(email_addresses)) # whatever is left return ret 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 def du(path): # Computes the size of all files in the path, like the `du` command. # Based on http://stackoverflow.com/a/17936789. Takes into account # soft and hard links. total_size = 0 seen = set() for dirpath, dirnames, filenames in os.walk(path): for f in filenames: fp = os.path.join(dirpath, f) try: stat = os.lstat(fp) except OSError: continue if stat.st_ino in seen: continue seen.add(stat.st_ino) total_size += stat.st_size return total_size def wait_for_service(port, public, env, timeout): # Block until a service on a given port (bound privately or publicly) # is taking connections, with a maximum timeout. import socket, time start = time.perf_counter() while True: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(timeout/3) try: s.connect(("127.0.0.1" if not public else env['PUBLIC_IP'], port)) return True except OSError: if time.perf_counter() > start+timeout: return False time.sleep(min(timeout/4, 1)) def fix_boto(): # Google Compute Engine instances install some Python-2-only boto plugins that # conflict with boto running under Python 3. Disable boto's default configuration # file prior to importing boto so that GCE's plugin is not loaded: import os os.environ["BOTO_CONFIG"] = "/etc/boto3.cfg" if __name__ == "__main__": from dns_update import get_dns_domains from web_update import get_web_domains, get_default_www_redirects env = load_environment() domains = get_dns_domains(env) | set(get_web_domains(env) + get_default_www_redirects(env)) domains = sort_domains(domains, env) for domain in domains: print(domain)