4 """Functionality common to all account classes.
6 Each subclass of Account must provide five methods:
7 (*) create() and destroy(), which are static;
8 (*) configure(), start(), and stop(), which are not.
10 configure(), which takes a record as its only argument, does
11 things like set up ssh keys. In addition, an Account subclass must
12 provide static member variables SHELL, which contains the unique shell
13 that it uses; and TYPE, a string that is used by the account creation
14 code. For no particular reason, TYPE is divided hierarchically by
15 periods; at the moment the only convention is that all sliver accounts
16 have type that begins with sliver.
18 There are any number of race conditions that may result from the fact
19 that account names are not unique over time. Moreover, it's a bad
20 idea to perform lengthy operations while holding the database lock.
21 In order to deal with both of these problems, we use a worker thread
22 for each account name that ever exists. On 32-bit systems with large
23 numbers of accounts, this may cause the NM process to run out of
24 *virtual* memory! This problem may be remedied by decreasing the
37 # When this variable is true, start after any ensure_created
39 # shell path -> account class association
41 # account type -> account class association
44 # these semaphores are acquired before creating/destroying an account
45 create_sem = threading.Semaphore(1)
46 destroy_sem = threading.Semaphore(1)
48 def register_class(acct_class):
49 """Call once for each account class. This method adds the class
50 to the dictionaries used to look up account classes by shell and
52 shell_acct_class[acct_class.SHELL] = acct_class
53 type_acct_class[acct_class.TYPE] = acct_class
56 # private account name -> worker object association and associated lock
57 name_worker_lock = threading.Lock()
61 return [pw_ent for pw_ent in pwd.getpwall() if pw_ent[6] in shell_acct_class]
64 """Return the names of all accounts on the system with recognized shells."""
65 return [pw_ent[0] for pw_ent in allpwents()]
68 """Return the worker object for a particular username. If no such object exists, create it first."""
69 name_worker_lock.acquire()
71 if name not in name_worker: name_worker[name] = Worker(name)
72 return name_worker[name]
73 finally: name_worker_lock.release()
77 def __init__(self, rec):
78 logger.verbose('accounts: Initing account %s'%rec['name'])
79 self.name = rec['name']
81 self.initscriptchanged = False
85 def create(name, vref = None): abstract
88 def destroy(name): abstract
90 def configure(self, rec):
91 """Write <rec['keys']> to my authorized_keys file."""
92 logger.verbose('accounts: configuring %s'%self.name)
93 new_keys = rec['keys']
94 if new_keys != self.keys:
95 # get the unix account info
96 gid = grp.getgrnam("slices")[2]
97 pw_info = pwd.getpwnam(self.name)
101 # write out authorized_keys file and conditionally create
102 # the .ssh subdir if need be.
103 dot_ssh = os.path.join(pw_dir,'.ssh')
104 if not os.path.isdir(dot_ssh):
105 if not os.path.isdir(pw_dir):
106 logger.verbose('accounts: WARNING: homedir %s does not exist for %s!'%(pw_dir,self.name))
108 os.chown(pw_dir, uid, gid)
111 auth_keys = os.path.join(dot_ssh,'authorized_keys')
112 tools.write_file(auth_keys, lambda f: f.write(new_keys))
114 # set access permissions and ownership properly
115 os.chmod(dot_ssh, 0700)
116 os.chown(dot_ssh, uid, gid)
117 os.chmod(auth_keys, 0600)
118 os.chown(auth_keys, uid, gid)
120 # set self.keys to new_keys only when all of the above ops succeed
123 logger.log('accounts: %s: installed ssh keys' % self.name)
125 def start(self, delay=0): pass
127 def is_running(self): pass
131 def __init__(self, name):
132 self.name = name # username
133 self._acct = None # the account object currently associated with this worker
135 def ensure_created(self, rec, startingup = Startingup):
136 """Check account type is still valid. If not, recreate sliver.
137 If still valid, check if running and configure/start if not."""
138 curr_class = self._get_class()
139 next_class = type_acct_class[rec['type']]
140 if next_class != curr_class:
141 self._destroy(curr_class)
143 try: next_class.create(self.name, rec['vref'])
144 finally: create_sem.release()
145 if not isinstance(self._acct, next_class): self._acct = next_class(rec)
147 not self.is_running() or \
148 next_class != curr_class or \
149 self._acct.initscriptchanged:
151 else: self._acct.configure(rec)
153 def ensure_destroyed(self): self._destroy(self._get_class())
155 def start(self, rec, d = 0):
156 self._acct.configure(rec)
157 self._acct.start(delay=d)
159 def stop(self): self._acct.stop()
161 def is_running(self):
162 if (self._acct != None) and self._acct.is_running():
166 logger.verbose("accounts: Worker(%s): is not running" % self.name)
169 def _destroy(self, curr_class):
172 destroy_sem.acquire()
173 try: curr_class.destroy(self.name)
174 finally: destroy_sem.release()
176 def _get_class(self):
177 try: shell = pwd.getpwnam(self.name)[6]
178 except KeyError: return None
179 return shell_acct_class[shell]