1 """Functionality common to all account classes.
3 Each subclass of Account must provide five methods: create() and
4 destroy(), which are static; configure(), start(), and stop(), which
5 are not. configure(), which takes a record as its only argument, does
6 things like set up ssh keys. In addition, an Account subclass must
7 provide static member variables SHELL, which contains the unique shell
8 that it uses; and TYPE, a string that is used by the account creation
9 code. For no particular reason, TYPE is divided hierarchically by
10 periods; at the moment the only convention is that all sliver accounts
11 have type that begins with sliver.
13 There are any number of race conditions that may result from the fact
14 that account names are not unique over time. Moreover, it's a bad
15 idea to perform lengthy operations while holding the database lock.
16 In order to deal with both of these problems, we use a worker thread
17 for each account name that ever exists. On 32-bit systems with large
18 numbers of accounts, this may cause the NM process to run out of
19 *virtual* memory! This problem may be remedied by decreasing the
33 # When this variable is true, start after any ensure_created
35 # shell path -> account class association
37 # account type -> account class association
40 # these semaphores are acquired before creating/destroying an account
41 create_sem = threading.Semaphore(1)
42 destroy_sem = threading.Semaphore(1)
44 def register_class(acct_class):
45 """Call once for each account class. This method adds the class to the dictionaries used to look up account classes by shell and type."""
46 shell_acct_class[acct_class.SHELL] = acct_class
47 type_acct_class[acct_class.TYPE] = acct_class
50 # private account name -> worker object association and associated lock
51 name_worker_lock = threading.Lock()
55 return [pw_ent for pw_ent in pwd.getpwall() if pw_ent[6] in shell_acct_class]
58 """Return the names of all accounts on the system with recognized shells."""
59 return [pw_ent[0] for pw_ent in allpwents()]
62 """Return the worker object for a particular username. If no such object exists, create it first."""
63 name_worker_lock.acquire()
65 if name not in name_worker: name_worker[name] = Worker(name)
66 return name_worker[name]
67 finally: name_worker_lock.release()
71 def __init__(self, rec):
72 logger.verbose('Initing account %s'%rec['name'])
73 self.name = rec['name']
75 self.initscriptchanged = False
79 def create(name, vref = None): abstract
81 def destroy(name): abstract
83 def configure(self, rec):
84 """Write <rec['keys']> to my authorized_keys file."""
85 logger.verbose('%s: in accounts:configure'%self.name)
86 new_keys = rec['keys']
87 if new_keys != self.keys:
89 gid = grp.getgrnam("slices")[2]
90 pw_info = pwd.getpwnam(self.name)
94 dot_ssh = pw_dir + '/.ssh'
95 if not os.access(dot_ssh, os.F_OK): os.mkdir(dot_ssh)
97 auth_keys = dot_ssh + '/authorized_keys'
98 tools.write_file(auth_keys, lambda f: f.write(new_keys))
100 os.chmod(dot_ssh, 0700)
101 os.chmod(auth_keys, 0600)
103 os.chown(dot_ssh, uid, gid)
104 os.chown(auth_keys, uid, gid)
106 logger.log('%s: installed ssh keys' % self.name)
108 def start(self, delay=0): pass
110 def is_running(self): pass
113 def __init__(self, name):
114 self.name = name # username
115 self._acct = None # the account object currently associated with this worker
117 def ensure_created(self, rec, startingup = Startingup):
118 """Check account type is still valid. If not, recreate sliver. If still valid,
119 check if running and configure/start if not."""
120 curr_class = self._get_class()
121 next_class = type_acct_class[rec['type']]
122 if next_class != curr_class:
123 self._destroy(curr_class)
125 try: next_class.create(self.name, rec['vref'])
126 finally: create_sem.release()
127 if not isinstance(self._acct, next_class): self._acct = next_class(rec)
129 not self.is_running() or \
130 next_class != curr_class or \
131 self._acct.initscriptchanged:
133 else: self._acct.configure(rec)
135 def ensure_destroyed(self): self._destroy(self._get_class())
137 def start(self, rec, d = 0):
138 self._acct.configure(rec)
139 self._acct.start(delay=d)
141 def stop(self): self._acct.stop()
143 def is_running(self):
144 if (self._acct != None) and self._acct.is_running():
148 logger.verbose("Worker(%s): is not running" % self.name)
151 def _destroy(self, curr_class):
154 destroy_sem.acquire()
155 try: curr_class.destroy(self.name)
156 finally: destroy_sem.release()
158 def _get_class(self):
159 try: shell = pwd.getpwnam(self.name)[6]
160 except KeyError: return None
161 return shell_acct_class[shell]