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1 | #! @PYTHON@ |
2 | ### -*-python-*- | |
3 | ### | |
4 | ### Build a CDB file from configuration file | |
5 | ### | |
6 | ### (c) 2007 Straylight/Edgeware | |
7 | ### | |
8 | ||
9 | ###----- Licensing notice --------------------------------------------------- | |
10 | ### | |
11 | ### This file is part of Trivial IP Encryption (TrIPE). | |
12 | ### | |
11ad66c2 MW |
13 | ### TrIPE is free software: you can redistribute it and/or modify it under |
14 | ### the terms of the GNU General Public License as published by the Free | |
15 | ### Software Foundation; either version 3 of the License, or (at your | |
16 | ### option) any later version. | |
6005ef9b | 17 | ### |
11ad66c2 MW |
18 | ### TrIPE is distributed in the hope that it will be useful, but WITHOUT |
19 | ### ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
20 | ### FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
21 | ### for more details. | |
6005ef9b MW |
22 | ### |
23 | ### You should have received a copy of the GNU General Public License | |
11ad66c2 | 24 | ### along with TrIPE. If not, see <https://www.gnu.org/licenses/>. |
6005ef9b MW |
25 | |
26 | VERSION = '@VERSION@' | |
27 | ||
28 | ###-------------------------------------------------------------------------- | |
29 | ### External dependencies. | |
30 | ||
31 | import ConfigParser as CP | |
32 | import mLib as M | |
33 | from optparse import OptionParser | |
34 | import cdb as CDB | |
35 | from sys import stdin, stdout, exit, argv | |
36 | import re as RX | |
37 | import os as OS | |
38 | ||
39 | ###-------------------------------------------------------------------------- | |
40 | ### Utilities. | |
41 | ||
42 | class CDBFake (object): | |
43 | """Like cdbmake, but just outputs data suitable for cdb-map.""" | |
44 | def __init__(me, file = stdout): | |
45 | me.file = file | |
46 | def add(me, key, value): | |
47 | me.file.write('%s:%s\n' % (key, value)) | |
48 | def finish(me): | |
49 | pass | |
50 | ||
51 | ###-------------------------------------------------------------------------- | |
52 | ### A bulk DNS resolver. | |
53 | ||
54 | class BulkResolver (object): | |
55 | """ | |
56 | Resolve a number of DNS names in parallel. | |
57 | ||
58 | The BulkResovler resolves a number of hostnames in parallel. Using it | |
59 | works in three phases: | |
60 | ||
61 | 1. You call prepare(HOSTNAME) a number of times, to feed in the hostnames | |
62 | you're interested in. | |
63 | ||
64 | 2. You call run() to actually drive the resolver. | |
65 | ||
66 | 3. You call lookup(HOSTNAME) to get the address you wanted. This will | |
67 | fail with KeyError if the resolver couldn't resolve the HOSTNAME. | |
68 | """ | |
69 | ||
70 | def __init__(me): | |
71 | """Initialize the resolver.""" | |
72 | me._resolvers = {} | |
73 | me._namemap = {} | |
74 | ||
75 | def prepare(me, host): | |
76 | """Prime the resolver to resolve the name HOST.""" | |
d8310a3a MW |
77 | if host not in me._resolvers: |
78 | me._resolvers[host] = M.SelResolveByName \ | |
79 | (host, | |
80 | lambda name, alias, addr: | |
81 | me._resolved(host, addr[0]), | |
82 | lambda: me._resolved(host, None)) | |
6005ef9b MW |
83 | |
84 | def run(me): | |
85 | """Run the background DNS resolver until it's finished.""" | |
86 | while me._resolvers: | |
87 | M.select() | |
88 | ||
89 | def lookup(me, host): | |
90 | """ | |
91 | Fetch the address corresponding to HOST. | |
92 | """ | |
93 | addr = me._namemap[host] | |
94 | if addr is None: | |
95 | raise KeyError, host | |
96 | return addr | |
97 | ||
98 | def _resolved(me, host, addr): | |
99 | """Callback function: remember that ADDR is the address for HOST.""" | |
100 | me._namemap[host] = addr | |
101 | del me._resolvers[host] | |
102 | ||
103 | ###-------------------------------------------------------------------------- | |
104 | ### The configuration parser. | |
105 | ||
106 | ## Match a $(VAR) configuration variable reference; group 1 is the VAR. | |
107 | r_ref = RX.compile(r'\$\(([^)]+)\)') | |
108 | ||
109 | ## Match a $[HOST] name resolution reference; group 1 is the HOST. | |
110 | r_resolve = RX.compile(r'\$\[([^]]+)\]') | |
111 | ||
bd3db76c MW |
112 | def _fmt_path(path): |
113 | return ' -> '.join(["`%s'" % hop for hop in path]) | |
114 | ||
115 | class AmbiguousOptionError (Exception): | |
116 | def __init__(me, key, patha, vala, pathb, valb): | |
117 | me.key = key | |
118 | me.patha, me.vala = patha, vala | |
119 | me.pathb, me.valb = pathb, valb | |
120 | def __str__(me): | |
121 | return "Ambiguous answer resolving key `%s': " \ | |
122 | "path %s yields `%s' but %s yields `%s'" % \ | |
123 | (me.key, _fmt_path(me.patha), me.vala, _fmt_path(me.pathb), me.valb) | |
124 | ||
125 | class InheritanceCycleError (Exception): | |
126 | def __init__(me, key, path): | |
127 | me.key = key | |
128 | me.path = path | |
129 | def __str__(me): | |
130 | return "Found a cycle %s looking up key `%s'" % \ | |
131 | (_fmt_path(me.path), me.key) | |
132 | ||
133 | class MissingKeyException (Exception): | |
134 | def __init__(me, sec, key): | |
135 | me.sec = sec | |
136 | me.key = key | |
137 | def __str__(me): | |
138 | return "Key `%s' not found in section `%s'" % (me.key, me.sec) | |
139 | ||
6005ef9b MW |
140 | class MyConfigParser (CP.RawConfigParser): |
141 | """ | |
142 | A more advanced configuration parser. | |
143 | ||
144 | This has two major enhancements over the standard ConfigParser which are | |
145 | relevant to us. | |
146 | ||
147 | * It recognizes `@inherits' keys and follows them when expanding a | |
148 | value. | |
149 | ||
150 | * It recognizes `$(VAR)' references to configuration variables during | |
151 | expansion and processes them correctly. | |
152 | ||
153 | * It recognizes `$[HOST]' name-resolver requests and handles them | |
154 | correctly. | |
155 | ||
156 | Use: | |
157 | ||
158 | 1. Call read(FILENAME) and/or read(FP, [FILENAME]) to slurp in the | |
159 | configuration data. | |
160 | ||
161 | 2. Call resolve() to collect the hostnames which need to be resolved and | |
162 | actually do the name resolution. | |
163 | ||
164 | 3. Call get(SECTION, ITEM) to collect the results, or items(SECTION) to | |
165 | iterate over them. | |
166 | """ | |
167 | ||
168 | def __init__(me): | |
169 | """ | |
170 | Initialize a new, empty configuration parser. | |
171 | """ | |
172 | CP.RawConfigParser.__init__(me) | |
173 | me._resolver = BulkResolver() | |
174 | ||
175 | def resolve(me): | |
176 | """ | |
177 | Works out all of the hostnames which need resolving and resolves them. | |
178 | ||
179 | Until you call this, attempts to fetch configuration items which need to | |
180 | resolve hostnames will fail! | |
181 | """ | |
182 | for sec in me.sections(): | |
183 | for key, value in me.items(sec, resolvep = False): | |
184 | for match in r_resolve.finditer(value): | |
185 | me._resolver.prepare(match.group(1)) | |
186 | me._resolver.run() | |
187 | ||
188 | def _expand(me, sec, string, resolvep): | |
189 | """ | |
190 | Expands $(...) and (optionally) $[...] placeholders in STRING. | |
191 | ||
192 | The SEC is the configuration section from which to satisfy $(...) | |
193 | requests. RESOLVEP is a boolean switch: do we bother to tax the resolver | |
194 | or not? This is turned off by the resolve() method while it's collecting | |
195 | hostnames to be resolved. | |
196 | """ | |
197 | string = r_ref.sub \ | |
198 | (lambda m: me.get(sec, m.group(1), resolvep), string) | |
199 | if resolvep: | |
200 | string = r_resolve.sub(lambda m: me._resolver.lookup(m.group(1)), | |
201 | string) | |
202 | return string | |
203 | ||
204 | def has_option(me, sec, key): | |
205 | """ | |
206 | Decide whether section SEC has a configuration key KEY. | |
207 | ||
208 | This version of the method properly handles the @inherit key. | |
209 | """ | |
bd3db76c | 210 | return key == 'name' or me._get(sec, key)[0] is not None |
6005ef9b | 211 | |
bd3db76c | 212 | def _get(me, sec, key, map = None, path = None): |
6005ef9b MW |
213 | """ |
214 | Low-level option-fetching method. | |
215 | ||
216 | Fetch the value for the named KEY from section SEC, or maybe | |
bd3db76c | 217 | (recursively) a section which SEC inherits from. |
6005ef9b | 218 | |
bd3db76c MW |
219 | Returns a pair VALUE, PATH. The value is not expanded; nor do we check |
220 | for the special `name' key. The caller is expected to do these things. | |
221 | Returns None if no value could be found. | |
222 | """ | |
6005ef9b | 223 | |
bd3db76c MW |
224 | ## If we weren't given a memoization map or path, then we'd better make |
225 | ## one. | |
226 | if map is None: map = {} | |
227 | if path is None: path = [] | |
6005ef9b | 228 | |
bd3db76c MW |
229 | ## If we've been this way before on another pass through then return the |
230 | ## value we found then. If we're still thinking about it then we've | |
231 | ## found a cycle. | |
232 | path.append(sec) | |
6005ef9b | 233 | try: |
bd3db76c MW |
234 | threadp, value = map[sec] |
235 | except KeyError: | |
236 | pass | |
237 | else: | |
238 | if threadp: | |
239 | raise InheritanceCycleError, (key, path) | |
240 | ||
241 | ## See whether the answer is ready waiting for us. | |
242 | try: | |
243 | v = CP.RawConfigParser.get(me, sec, key) | |
6005ef9b | 244 | except CP.NoOptionError: |
bd3db76c MW |
245 | pass |
246 | else: | |
247 | p = path[:] | |
248 | path.pop() | |
249 | return v, p | |
250 | ||
251 | ## No, apparently, not. Find out our list of parents. | |
252 | try: | |
253 | parents = CP.RawConfigParser.get(me, sec, '@inherit').\ | |
254 | replace(',', ' ').split() | |
255 | except CP.NoOptionError: | |
256 | parents = [] | |
257 | ||
258 | ## Initially we have no idea. | |
259 | value = None | |
260 | winner = None | |
261 | ||
262 | ## Go through our parents and ask them what they think. | |
263 | map[sec] = True, None | |
264 | for p in parents: | |
265 | ||
266 | ## See whether we get an answer. If not, keep on going. | |
267 | v, pp = me._get(p, key, map, path) | |
268 | if v is None: continue | |
269 | ||
270 | ## If we got an answer, check that it matches any previous ones. | |
271 | if value is None: | |
272 | value = v | |
273 | winner = pp | |
274 | elif value != v: | |
275 | raise AmbiguousOptionError, (key, winner, value, pp, v) | |
276 | ||
277 | ## That's the best we could manage. | |
278 | path.pop() | |
279 | map[sec] = False, value | |
280 | return value, winner | |
6005ef9b MW |
281 | |
282 | def get(me, sec, key, resolvep = True): | |
283 | """ | |
284 | Retrieve the value of KEY from section SEC. | |
285 | """ | |
bd3db76c MW |
286 | |
287 | ## Special handling for the `name' key. | |
288 | if key == 'name': | |
289 | try: value = CP.RawConfigParser.get(me, sec, key) | |
290 | except CP.NoOptionError: value = sec | |
291 | else: | |
292 | value, _ = me._get(sec, key) | |
293 | if value is None: | |
294 | raise MissingKeyException, (sec, key) | |
295 | ||
296 | ## Expand the value and return it. | |
297 | return me._expand(sec, value, resolvep) | |
6005ef9b MW |
298 | |
299 | def items(me, sec, resolvep = True): | |
300 | """ | |
301 | Return a list of (NAME, VALUE) items in section SEC. | |
302 | ||
303 | This extends the default method by handling the inheritance chain. | |
304 | """ | |
bd3db76c MW |
305 | |
306 | ## Initialize for a depth-first walk of the inheritance graph. | |
6005ef9b | 307 | d = {} |
bd3db76c | 308 | visited = {} |
6005ef9b | 309 | basesec = sec |
bd3db76c MW |
310 | stack = [sec] |
311 | ||
312 | ## Visit nodes, collecting their keys. Don't believe the values: | |
313 | ## resolving inheritance is too hard to do like this. | |
314 | while stack: | |
315 | sec = stack.pop() | |
316 | if sec in visited: continue | |
317 | visited[sec] = True | |
318 | ||
6005ef9b | 319 | for key, value in CP.RawConfigParser.items(me, sec): |
bd3db76c MW |
320 | if key == '@inherit': stack += value.replace(',', ' ').split() |
321 | else: d[key] = None | |
322 | ||
323 | ## Now collect the values for the known keys, one by one. | |
324 | items = [] | |
325 | for key in d: items.append((key, me.get(basesec, key, resolvep))) | |
326 | ||
327 | ## And we're done. | |
328 | return items | |
6005ef9b MW |
329 | |
330 | ###-------------------------------------------------------------------------- | |
331 | ### Command-line handling. | |
332 | ||
333 | def inputiter(things): | |
334 | """ | |
335 | Iterate over command-line arguments, returning corresponding open files. | |
336 | ||
337 | If none were given, or one is `-', assume standard input; if one is a | |
338 | directory, scan it for files other than backups; otherwise return the | |
339 | opened files. | |
340 | """ | |
341 | ||
342 | if not things: | |
343 | if OS.isatty(stdin.fileno()): | |
344 | M.die('no input given, and stdin is a terminal') | |
345 | yield stdin | |
346 | else: | |
347 | for thing in things: | |
348 | if thing == '-': | |
349 | yield stdin | |
350 | elif OS.path.isdir(thing): | |
351 | for item in OS.listdir(thing): | |
352 | if item.endswith('~') or item.endswith('#'): | |
353 | continue | |
354 | name = OS.path.join(thing, item) | |
355 | if not OS.path.isfile(name): | |
356 | continue | |
357 | yield file(name) | |
358 | else: | |
359 | yield file(thing) | |
360 | ||
361 | def parse_options(argv = argv): | |
362 | """ | |
363 | Parse command-line options, returning a pair (OPTS, ARGS). | |
364 | """ | |
365 | M.ego(argv[0]) | |
366 | op = OptionParser(usage = '%prog [-c CDB] INPUT...', | |
367 | version = '%%prog (tripe, version %s)' % VERSION) | |
368 | op.add_option('-c', '--cdb', metavar = 'CDB', | |
369 | dest = 'cdbfile', default = None, | |
370 | help = 'Compile output into a CDB file.') | |
371 | opts, args = op.parse_args(argv) | |
372 | return opts, args | |
373 | ||
374 | ###-------------------------------------------------------------------------- | |
375 | ### Main code. | |
376 | ||
377 | def getconf(args): | |
378 | """ | |
379 | Read the configuration files and return the accumulated result. | |
380 | ||
381 | We make sure that all hostnames have been properly resolved. | |
382 | """ | |
383 | conf = MyConfigParser() | |
384 | for f in inputiter(args): | |
385 | conf.readfp(f) | |
386 | conf.resolve() | |
387 | return conf | |
388 | ||
389 | def output(conf, cdb): | |
390 | """ | |
391 | Output the configuration information CONF to the database CDB. | |
392 | ||
393 | This is where the special `user' and `auto' database entries get set. | |
394 | """ | |
395 | auto = [] | |
527cd49f | 396 | for sec in sorted(conf.sections()): |
6005ef9b MW |
397 | if sec.startswith('@'): |
398 | continue | |
399 | elif sec.startswith('$'): | |
400 | label = sec | |
401 | else: | |
402 | label = 'P%s' % sec | |
403 | if conf.has_option(sec, 'auto') and \ | |
404 | conf.get(sec, 'auto') in ('y', 'yes', 't', 'true', '1', 'on'): | |
405 | auto.append(sec) | |
406 | if conf.has_option(sec, 'user'): | |
407 | cdb.add('U%s' % conf.get(sec, 'user'), sec) | |
408 | url = M.URLEncode(laxp = True, semip = True) | |
527cd49f | 409 | for key, value in sorted(conf.items(sec), key = lambda (k, v): k): |
6005ef9b MW |
410 | if not key.startswith('@'): |
411 | url.encode(key, ' '.join(M.split(value)[0])) | |
412 | cdb.add(label, url.result) | |
413 | cdb.add('%AUTO', ' '.join(auto)) | |
414 | cdb.finish() | |
415 | ||
416 | def main(): | |
417 | """Main program.""" | |
418 | opts, args = parse_options() | |
419 | if opts.cdbfile: | |
420 | cdb = CDB.cdbmake(opts.cdbfile, opts.cdbfile + '.new') | |
421 | else: | |
422 | cdb = CDBFake() | |
423 | conf = getconf(args[1:]) | |
424 | output(conf, cdb) | |
425 | ||
426 | if __name__ == '__main__': | |
427 | main() | |
428 | ||
429 | ###----- That's all, folks -------------------------------------------------- |