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
36 # When this variable is true, start after any ensure_created
38 # shell path -> account class association
40 # account type -> account class association
43 # these semaphores are acquired before creating/destroying an account
44 create_sem = threading.Semaphore(1)
45 destroy_sem = threading.Semaphore(1)
47 def register_class(acct_class):
48 """Call once for each account class. This method adds the class
49 to the dictionaries used to look up account classes by shell and
51 shell_acct_class[acct_class.SHELL] = acct_class
52 type_acct_class[acct_class.TYPE] = acct_class
55 # private account name -> worker object association and associated lock
56 name_worker_lock = threading.Lock()
60 return [pw_ent for pw_ent in pwd.getpwall() if pw_ent[6] in shell_acct_class]
63 """Return the names of all accounts on the system with recognized shells."""
64 return [pw_ent[0] for pw_ent in allpwents()]
67 """Return the worker object for a particular username. If no such object exists, create it first."""
68 name_worker_lock.acquire()
70 if name not in name_worker: name_worker[name] = Worker(name)
71 return name_worker[name]
72 finally: name_worker_lock.release()
76 def __init__(self, rec):
77 logger.verbose('accounts: Initing account %s'%rec['name'])
78 self.name = rec['name']
83 def create(name, vref = None): abstract
86 def destroy(name): abstract
88 def configure(self, rec):
89 """Write <rec['keys']> to my authorized_keys file."""
90 logger.verbose('accounts: configuring %s'%self.name)
91 new_keys = rec['keys']
92 if new_keys != self.keys:
93 # get the unix account info
94 gid = grp.getgrnam("slices")[2]
95 pw_info = pwd.getpwnam(self.name)
99 # write out authorized_keys file and conditionally create
100 # the .ssh subdir if need be.
101 dot_ssh = os.path.join(pw_dir,'.ssh')
102 if not os.path.isdir(dot_ssh):
103 if not os.path.isdir(pw_dir):
104 logger.verbose('accounts: WARNING: homedir %s does not exist for %s!'%(pw_dir,self.name))
106 os.chown(pw_dir, uid, gid)
109 auth_keys = os.path.join(dot_ssh,'authorized_keys')
110 tools.write_file(auth_keys, lambda f: f.write(new_keys))
112 # set access permissions and ownership properly
113 os.chmod(dot_ssh, 0700)
114 os.chown(dot_ssh, uid, gid)
115 os.chmod(auth_keys, 0600)
116 os.chown(auth_keys, uid, gid)
118 # set self.keys to new_keys only when all of the above ops succeed
121 logger.log('accounts: %s: installed ssh keys' % self.name)
123 def start(self, delay=0): pass
125 def is_running(self): pass
129 def __init__(self, name):
130 self.name = name # username
131 self._acct = None # the account object currently associated with this worker
133 def ensure_created(self, rec, startingup = Startingup):
134 """Check account type is still valid. If not, recreate sliver.
135 If still valid, check if running and configure/start if not."""
136 logger.log_data_in_file(rec,"/var/lib/nodemanager/%s.rec.txt"%rec['name'],
137 'raw rec captured in ensure_created',logger.LOG_VERBOSE)
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)
146 if not self.is_running() or startingup or next_class != curr_class:
148 else: self._acct.configure(rec)
150 def ensure_destroyed(self): self._destroy(self._get_class())
152 def start(self, rec, d = 0):
153 self._acct.configure(rec)
154 self._acct.start(delay=d)
156 def stop(self): self._acct.stop()
158 def is_running(self):
159 if (self._acct != None) and self._acct.is_running():
163 logger.verbose("accounts: Worker(%s): is not running" % self.name)
166 def _destroy(self, curr_class):
169 destroy_sem.acquire()
170 try: curr_class.destroy(self.name)
171 finally: destroy_sem.release()
173 def _get_class(self):
174 try: shell = pwd.getpwnam(self.name)[6]
175 except KeyError: return None
176 return shell_acct_class[shell]