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
26 from grp import getgrnam
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 dot_ssh = '/home/%s/.ssh' % self.name
90 if not os.access(dot_ssh, os.F_OK): os.mkdir(dot_ssh)
91 os.chmod(dot_ssh, 0700)
92 tools.write_file(dot_ssh + '/authorized_keys', lambda f: f.write(new_keys))
93 logger.log('%s: installing ssh keys' % self.name)
94 user = pwd.getpwnam(self.name)[2]
95 group = getgrnam("slices")[2]
96 os.chown(dot_ssh, user, group)
97 os.chown(dot_ssh + '/authorized_keys', user, group)
99 def start(self, delay=0): pass
101 def is_running(self): pass
104 def __init__(self, name):
105 self.name = name # username
106 self._acct = None # the account object currently associated with this worker
108 def ensure_created(self, rec, startingup = Startingup):
109 """Check account type is still valid. If not, recreate sliver. If still valid,
110 check if running and configure/start if not."""
111 curr_class = self._get_class()
112 next_class = type_acct_class[rec['type']]
113 if next_class != curr_class:
114 self._destroy(curr_class)
116 try: next_class.create(self.name, rec['vref'])
117 finally: create_sem.release()
118 if not isinstance(self._acct, next_class): self._acct = next_class(rec)
120 not self.is_running() or \
121 next_class != curr_class or \
122 self._acct.initscriptchanged:
124 else: self._acct.configure(rec)
126 def ensure_destroyed(self): self._destroy(self._get_class())
128 def start(self, rec, d = 0):
129 self._acct.configure(rec)
130 self._acct.start(delay=d)
132 def stop(self): self._acct.stop()
134 def is_running(self):
135 if (self._acct != None) and self._acct.is_running():
139 logger.verbose("Worker(%s): is not running" % self.name)
142 def _destroy(self, curr_class):
145 destroy_sem.acquire()
146 try: curr_class.destroy(self.name)
147 finally: destroy_sem.release()
149 def _get_class(self):
150 try: shell = pwd.getpwnam(self.name)[6]
151 except KeyError: return None
152 return shell_acct_class[shell]