4 """Functionality common to all account classes.
6 Each subclass of Account must provide five methods: create() and
7 destroy(), which are static; configure(), start(), and stop(), which
8 are not. configure(), which takes a record as its only argument, does
9 things like set up ssh keys. In addition, an Account subclass must
10 provide static member variables SHELL, which contains the unique shell
11 that it uses; and TYPE, a string that is used by the account creation
12 code. For no particular reason, TYPE is divided hierarchically by
13 periods; at the moment the only convention is that all sliver accounts
14 have type that begins with sliver.
16 There are any number of race conditions that may result from the fact
17 that account names are not unique over time. Moreover, it's a bad
18 idea to perform lengthy operations while holding the database lock.
19 In order to deal with both of these problems, we use a worker thread
20 for each account name that ever exists. On 32-bit systems with large
21 numbers of accounts, this may cause the NM process to run out of
22 *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 to the dictionaries used to look up account classes by shell and type."""
49 shell_acct_class[acct_class.SHELL] = acct_class
50 type_acct_class[acct_class.TYPE] = acct_class
53 # private account name -> worker object association and associated lock
54 name_worker_lock = threading.Lock()
58 return [pw_ent for pw_ent in pwd.getpwall() if pw_ent[6] in shell_acct_class]
61 """Return the names of all accounts on the system with recognized shells."""
62 return [pw_ent[0] for pw_ent in allpwents()]
65 """Return the worker object for a particular username. If no such object exists, create it first."""
66 name_worker_lock.acquire()
68 if name not in name_worker: name_worker[name] = Worker(name)
69 return name_worker[name]
70 finally: name_worker_lock.release()
74 def __init__(self, rec):
75 logger.verbose('accounts: Initing account %s'%rec['name'])
76 self.name = rec['name']
78 self.initscriptchanged = False
82 def create(name, vref = None): abstract
84 def destroy(name): abstract
86 def configure(self, rec):
87 """Write <rec['keys']> to my authorized_keys file."""
88 logger.verbose('accounts: configuring %s'%self.name)
89 new_keys = rec['keys']
90 if new_keys != self.keys:
91 # get the unix account info
92 gid = grp.getgrnam("slices")[2]
93 pw_info = pwd.getpwnam(self.name)
97 # write out authorized_keys file and conditionally create
98 # the .ssh subdir if need be.
99 dot_ssh = os.path.join(pw_dir,'.ssh')
100 if not os.path.isdir(dot_ssh):
101 if not os.path.isdir(pw_dir):
102 logger.verbose('accounts: WARNING: homedir %s does not exist for %s!'%(pw_dir,self.name))
104 os.chown(pw_dir, uid, gid)
107 auth_keys = os.path.join(dot_ssh,'authorized_keys')
108 tools.write_file(auth_keys, lambda f: f.write(new_keys))
110 # set access permissions and ownership properly
111 os.chmod(dot_ssh, 0700)
112 os.chown(dot_ssh, uid, gid)
113 os.chmod(auth_keys, 0600)
114 os.chown(auth_keys, uid, gid)
116 # set self.keys to new_keys only when all of the above ops succeed
119 logger.log('accounts: %s: installed ssh keys' % self.name)
121 def start(self, delay=0): pass
123 def is_running(self): pass
126 def __init__(self, name):
127 self.name = name # username
128 self._acct = None # the account object currently associated with this worker
130 def ensure_created(self, rec, startingup = Startingup):
131 """Check account type is still valid. If not, recreate sliver. If still valid,
132 check if running and configure/start if not."""
133 curr_class = self._get_class()
134 next_class = type_acct_class[rec['type']]
135 if next_class != curr_class:
136 self._destroy(curr_class)
138 try: next_class.create(self.name, rec['vref'])
139 finally: create_sem.release()
140 if not isinstance(self._acct, next_class): self._acct = next_class(rec)
142 not self.is_running() or \
143 next_class != curr_class or \
144 self._acct.initscriptchanged:
146 else: self._acct.configure(rec)
148 def ensure_destroyed(self): self._destroy(self._get_class())
150 def start(self, rec, d = 0):
151 self._acct.configure(rec)
152 self._acct.start(delay=d)
154 def stop(self): self._acct.stop()
156 def is_running(self):
157 if (self._acct != None) and self._acct.is_running():
161 logger.verbose("accounts: Worker(%s): is not running" % self.name)
164 def _destroy(self, curr_class):
167 destroy_sem.acquire()
168 try: curr_class.destroy(self.name)
169 finally: destroy_sem.release()
171 def _get_class(self):
172 try: shell = pwd.getpwnam(self.name)[6]
173 except KeyError: return None
174 return shell_acct_class[shell]