Commit | Line | Data |
---|---|---|
6005ef9b MW |
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 | ||
6005ef9b MW |
31 | import mLib as M |
32 | from optparse import OptionParser | |
33 | import cdb as CDB | |
34 | from sys import stdin, stdout, exit, argv | |
35 | import re as RX | |
36 | import os as OS | |
b7e5aa06 | 37 | from cStringIO import StringIO |
6005ef9b MW |
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: | |
171206b5 | 95 | raise KeyError(host) |
6005ef9b MW |
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 | ||
b7e5aa06 MW |
106 | ## Match a comment or empty line. |
107 | RX_COMMENT = RX.compile(r'(?x) ^ \s* (?: $ | [;#])') | |
108 | ||
109 | ## Match a section group header. | |
110 | RX_GRPHDR = RX.compile(r'(?x) ^ \s* \[ (.*) \] \s* $') | |
111 | ||
112 | ## Match an assignment line. | |
113 | RX_ASSGN = RX.compile(r'''(?x) ^ | |
114 | ([^\s:=] (?: [^:=]* [^\s:=])?) | |
115 | \s* [:=] \s* | |
116 | (| \S | \S.*\S) | |
117 | \s* $''') | |
118 | ||
119 | ## Match a continuation line. | |
120 | RX_CONT = RX.compile(r'''(?x) ^ \s+ | |
121 | (| \S | \S.*\S) | |
122 | \s* $''') | |
123 | ||
6005ef9b | 124 | ## Match a $(VAR) configuration variable reference; group 1 is the VAR. |
2d51bc9f | 125 | RX_REF = RX.compile(r'(?x) \$ \( ([^)]+) \)') |
6005ef9b MW |
126 | |
127 | ## Match a $[HOST] name resolution reference; group 1 is the HOST. | |
2d51bc9f | 128 | RX_RESOLVE = RX.compile(r'(?x) \$ \[ ([^]]+) \]') |
6005ef9b | 129 | |
b7e5aa06 MW |
130 | class ConfigSyntaxError (Exception): |
131 | def __init__(me, fname, lno, msg): | |
132 | me.fname = fname | |
133 | me.lno = lno | |
134 | me.msg = msg | |
135 | def __str__(me): | |
136 | return '%s:%d: %s' % (me.fname, me.lno, me.msg) | |
137 | ||
bd3db76c MW |
138 | def _fmt_path(path): |
139 | return ' -> '.join(["`%s'" % hop for hop in path]) | |
140 | ||
141 | class AmbiguousOptionError (Exception): | |
142 | def __init__(me, key, patha, vala, pathb, valb): | |
143 | me.key = key | |
144 | me.patha, me.vala = patha, vala | |
145 | me.pathb, me.valb = pathb, valb | |
146 | def __str__(me): | |
147 | return "Ambiguous answer resolving key `%s': " \ | |
148 | "path %s yields `%s' but %s yields `%s'" % \ | |
149 | (me.key, _fmt_path(me.patha), me.vala, _fmt_path(me.pathb), me.valb) | |
150 | ||
151 | class InheritanceCycleError (Exception): | |
152 | def __init__(me, key, path): | |
153 | me.key = key | |
154 | me.path = path | |
155 | def __str__(me): | |
156 | return "Found a cycle %s looking up key `%s'" % \ | |
157 | (_fmt_path(me.path), me.key) | |
158 | ||
e3ec3a3a MW |
159 | class MissingSectionException (Exception): |
160 | def __init__(me, sec): | |
161 | me.key = key | |
162 | def __str__(me): | |
163 | return "Section `%s' not found" % (me.sec) | |
164 | ||
bd3db76c MW |
165 | class MissingKeyException (Exception): |
166 | def __init__(me, sec, key): | |
167 | me.sec = sec | |
168 | me.key = key | |
169 | def __str__(me): | |
170 | return "Key `%s' not found in section `%s'" % (me.key, me.sec) | |
171 | ||
e3ec3a3a MW |
172 | class ConfigSection (object): |
173 | """ | |
174 | A section in a configuration parser. | |
175 | ||
176 | This is where a lot of the nitty-gritty stuff actually happens. The | |
177 | `MyConfigParser' knows a lot about the internals of this class, which saves | |
178 | on building a complicated interface. | |
179 | """ | |
180 | ||
181 | def __init__(me, name, cp): | |
182 | """Initialize a new, empty section with a given NAME and parent CP.""" | |
886350e8 MW |
183 | |
184 | ## The cache maps item keys to entries, which consist of a pair of | |
185 | ## objects. There are four possible states for a cache entry: | |
186 | ## | |
187 | ## * missing -- there is no entry at all with this key, so we must | |
188 | ## search for it; | |
189 | ## | |
190 | ## * None, None -- we are actively trying to resolve this key, so if we | |
191 | ## encounter this state, we have found a cycle in the inheritance | |
192 | ## graph; | |
193 | ## | |
194 | ## * None, [] -- we know that this key isn't reachable through any of | |
195 | ## our parents; | |
196 | ## | |
197 | ## * VALUE, PATH -- we know that the key resolves to VALUE, along the | |
198 | ## PATH from us (exclusive) to the defining parent (inclusive). | |
e3ec3a3a MW |
199 | me.name = name |
200 | me._itemmap = dict() | |
886350e8 | 201 | me._cache = dict() |
e3ec3a3a MW |
202 | me._cp = cp |
203 | ||
204 | def _expand(me, string, resolvep): | |
205 | """ | |
206 | Expands $(...) and (optionally) $[...] placeholders in STRING. | |
207 | ||
208 | RESOLVEP is a boolean switch: do we bother to tax the resolver or not? | |
209 | This is turned off by MyConfigParser's resolve() method while it's | |
210 | collecting hostnames to be resolved. | |
211 | """ | |
212 | string = RX_REF.sub \ | |
213 | (lambda m: me.get(m.group(1), resolvep), string) | |
214 | if resolvep: | |
215 | string = RX_RESOLVE.sub(lambda m: me._cp._resolver.lookup(m.group(1)), | |
216 | string) | |
217 | return string | |
218 | ||
4251f8ad MW |
219 | def _parents(me): |
220 | """Yield this section's parents.""" | |
221 | try: names = me._itemmap['@inherit'] | |
222 | except KeyError: return | |
223 | for name in names.replace(',', ' ').split(): | |
224 | yield me._cp.section(name) | |
225 | ||
886350e8 | 226 | def _get(me, key, path = None): |
e3ec3a3a MW |
227 | """ |
228 | Low-level option-fetching method. | |
229 | ||
230 | Fetch the value for the named KEY in this section, or maybe (recursively) | |
231 | a section which it inherits from. | |
232 | ||
233 | Returns a pair VALUE, PATH. The value is not expanded; nor do we check | |
234 | for the special `name' key. The caller is expected to do these things. | |
235 | Returns None if no value could be found. | |
236 | """ | |
237 | ||
886350e8 | 238 | ## If we weren't given a path, then we'd better make one. |
e3ec3a3a MW |
239 | if path is None: path = [] |
240 | ||
241 | ## Extend the path to cover us, but remember to remove us again when | |
242 | ## we've finished. If we need to pass the current path back upwards, | |
243 | ## then remember to take a copy. | |
244 | path.append(me.name) | |
245 | try: | |
246 | ||
886350e8 MW |
247 | ## If we've been this way before on another pass through then return the |
248 | ## value we found then. If we're still thinking about it then we've | |
249 | ## found a cycle. | |
250 | try: v, p = me._cache[key] | |
e3ec3a3a MW |
251 | except KeyError: pass |
252 | else: | |
886350e8 MW |
253 | if p is None: raise InheritanceCycleError(key, path[:]) |
254 | else: return v, path + p | |
e3ec3a3a MW |
255 | |
256 | ## See whether the answer is ready waiting for us. | |
257 | try: v = me._itemmap[key] | |
258 | except KeyError: pass | |
886350e8 MW |
259 | else: |
260 | p = path[:] | |
261 | me._cache[key] = v, [] | |
262 | return v, p | |
e3ec3a3a | 263 | |
e3ec3a3a MW |
264 | ## Initially we have no idea. |
265 | value = None | |
886350e8 | 266 | winner = [] |
e3ec3a3a MW |
267 | |
268 | ## Go through our parents and ask them what they think. | |
886350e8 | 269 | me._cache[key] = None, None |
4251f8ad | 270 | for p in me._parents(): |
e3ec3a3a MW |
271 | |
272 | ## See whether we get an answer. If not, keep on going. | |
886350e8 | 273 | v, pp = p._get(key, path) |
e3ec3a3a MW |
274 | if v is None: continue |
275 | ||
276 | ## If we got an answer, check that it matches any previous ones. | |
277 | if value is None: | |
278 | value = v | |
279 | winner = pp | |
280 | elif value != v: | |
281 | raise AmbiguousOptionError(key, winner, value, pp, v) | |
282 | ||
283 | ## That's the best we could manage. | |
886350e8 | 284 | me._cache[key] = value, winner[len(path):] |
e3ec3a3a MW |
285 | return value, winner |
286 | ||
287 | finally: | |
288 | ## Remove us from the path again. | |
289 | path.pop() | |
290 | ||
291 | def get(me, key, resolvep = True): | |
292 | """ | |
293 | Retrieve the value of KEY from this section. | |
294 | """ | |
295 | ||
296 | ## Special handling for the `name' key. | |
297 | if key == 'name': | |
298 | value = me._itemmap.get('name', me.name) | |
299 | else: | |
300 | value, _ = me._get(key) | |
301 | if value is None: | |
302 | raise MissingKeyException(me.name, key) | |
303 | ||
304 | ## Expand the value and return it. | |
305 | return me._expand(value, resolvep) | |
306 | ||
307 | def items(me, resolvep = True): | |
308 | """ | |
85341d9c | 309 | Yield a list of item names in the section. |
e3ec3a3a MW |
310 | """ |
311 | ||
312 | ## Initialize for a depth-first walk of the inheritance graph. | |
6e5794ef | 313 | seen = {} |
f417591a | 314 | visiting = { me.name: True } |
4251f8ad | 315 | stack = [me] |
e3ec3a3a MW |
316 | |
317 | ## Visit nodes, collecting their keys. Don't believe the values: | |
318 | ## resolving inheritance is too hard to do like this. | |
319 | while stack: | |
4251f8ad | 320 | sec = stack.pop() |
f417591a MW |
321 | for p in sec._parents(): |
322 | if p.name not in visiting: | |
323 | stack.append(p); visiting[p.name] = True | |
e3ec3a3a | 324 | |
4251f8ad | 325 | for key in sec._itemmap.iterkeys(): |
6e5794ef | 326 | if key != '@inherit': seen[key] = None |
e3ec3a3a | 327 | |
e3ec3a3a | 328 | ## And we're done. |
6e5794ef | 329 | return seen.iterkeys() |
e3ec3a3a | 330 | |
b7e5aa06 | 331 | class MyConfigParser (object): |
6005ef9b MW |
332 | """ |
333 | A more advanced configuration parser. | |
334 | ||
b7e5aa06 | 335 | This has four major enhancements over the standard ConfigParser which are |
6005ef9b MW |
336 | relevant to us. |
337 | ||
338 | * It recognizes `@inherits' keys and follows them when expanding a | |
339 | value. | |
340 | ||
341 | * It recognizes `$(VAR)' references to configuration variables during | |
342 | expansion and processes them correctly. | |
343 | ||
344 | * It recognizes `$[HOST]' name-resolver requests and handles them | |
345 | correctly. | |
346 | ||
b7e5aa06 MW |
347 | * Its parsing behaviour is well-defined. |
348 | ||
6005ef9b MW |
349 | Use: |
350 | ||
b7e5aa06 | 351 | 1. Call parse(FILENAME) to slurp in the configuration data. |
6005ef9b MW |
352 | |
353 | 2. Call resolve() to collect the hostnames which need to be resolved and | |
354 | actually do the name resolution. | |
355 | ||
e3ec3a3a MW |
356 | 3. Call sections() to get a list of the configuration sections, or |
357 | section(NAME) to find a named section. | |
358 | ||
359 | 4. Call get(ITEM) on a section to collect the results, or items() to | |
6005ef9b MW |
360 | iterate over them. |
361 | """ | |
362 | ||
363 | def __init__(me): | |
364 | """ | |
365 | Initialize a new, empty configuration parser. | |
366 | """ | |
b7e5aa06 | 367 | me._sectmap = dict() |
6005ef9b MW |
368 | me._resolver = BulkResolver() |
369 | ||
b7e5aa06 MW |
370 | def parse(me, f): |
371 | """ | |
372 | Parse configuration from a file F. | |
373 | """ | |
374 | ||
375 | ## Initial parser state. | |
376 | sect = None | |
377 | key = None | |
378 | val = None | |
379 | lno = 0 | |
380 | ||
381 | ## An unpleasant hack. Python makes it hard to capture a value in a | |
382 | ## variable and examine it in a single action, and this is the best that | |
383 | ## I came up with. | |
384 | m = [None] | |
385 | def match(rx): m[0] = rx.match(line); return m[0] | |
386 | ||
387 | ## Commit a key's value when we've determined that there are no further | |
388 | ## continuation lines. | |
389 | def flush(): | |
e3ec3a3a | 390 | if key is not None: sect._itemmap[key] = val.getvalue() |
b7e5aa06 MW |
391 | |
392 | ## Work through all of the input lines. | |
393 | for line in f: | |
394 | lno += 1 | |
395 | ||
396 | if match(RX_COMMENT): | |
397 | ## A comment or a blank line. Nothing doing. (This means that we | |
398 | ## leave out blank lines which look like they might be continuation | |
399 | ## lines.) | |
400 | ||
401 | pass | |
402 | ||
403 | elif match(RX_GRPHDR): | |
404 | ## A section header. Flush out any previous value and set up the new | |
405 | ## group. | |
406 | ||
407 | flush() | |
408 | name = m[0].group(1) | |
409 | try: sect = me._sectmap[name] | |
e3ec3a3a | 410 | except KeyError: sect = me._sectmap[name] = ConfigSection(name, me) |
b7e5aa06 MW |
411 | key = None |
412 | ||
413 | elif match(RX_ASSGN): | |
414 | ## A new assignment. Flush out the old one, and set up to store this | |
415 | ## one. | |
416 | ||
417 | if sect is None: | |
418 | raise ConfigSyntaxError(f.name, lno, 'no active section to update') | |
419 | flush() | |
420 | key = m[0].group(1) | |
421 | val = StringIO(); val.write(m[0].group(2)) | |
422 | ||
423 | elif match(RX_CONT): | |
424 | ## A continuation line. Accumulate the value. | |
425 | ||
426 | if key is None: | |
427 | raise ConfigSyntaxError(f.name, lno, 'no config value to continue') | |
428 | val.write('\n'); val.write(m[0].group(1)) | |
429 | ||
430 | else: | |
431 | ## Something else. | |
432 | ||
433 | raise ConfigSyntaxError(f.name, lno, 'incomprehensible line') | |
434 | ||
435 | ## Don't forget to commit any final value material. | |
436 | flush() | |
437 | ||
e3ec3a3a MW |
438 | def section(me, name): |
439 | """Return a ConfigSection with the given NAME.""" | |
440 | try: return me._sectmap[name] | |
441 | except KeyError: raise MissingSectionException(name) | |
442 | ||
b7e5aa06 | 443 | def sections(me): |
e3ec3a3a MW |
444 | """Yield the known sections.""" |
445 | return me._sectmap.itervalues() | |
b7e5aa06 | 446 | |
6005ef9b MW |
447 | def resolve(me): |
448 | """ | |
449 | Works out all of the hostnames which need resolving and resolves them. | |
450 | ||
451 | Until you call this, attempts to fetch configuration items which need to | |
452 | resolve hostnames will fail! | |
453 | """ | |
e3ec3a3a | 454 | for sec in me.sections(): |
85341d9c MW |
455 | for key in sec.items(): |
456 | value = sec.get(key, resolvep = False) | |
2d51bc9f | 457 | for match in RX_RESOLVE.finditer(value): |
6005ef9b MW |
458 | me._resolver.prepare(match.group(1)) |
459 | me._resolver.run() | |
460 | ||
6005ef9b MW |
461 | ###-------------------------------------------------------------------------- |
462 | ### Command-line handling. | |
463 | ||
464 | def inputiter(things): | |
465 | """ | |
466 | Iterate over command-line arguments, returning corresponding open files. | |
467 | ||
468 | If none were given, or one is `-', assume standard input; if one is a | |
469 | directory, scan it for files other than backups; otherwise return the | |
470 | opened files. | |
471 | """ | |
472 | ||
473 | if not things: | |
474 | if OS.isatty(stdin.fileno()): | |
475 | M.die('no input given, and stdin is a terminal') | |
476 | yield stdin | |
477 | else: | |
478 | for thing in things: | |
479 | if thing == '-': | |
480 | yield stdin | |
481 | elif OS.path.isdir(thing): | |
482 | for item in OS.listdir(thing): | |
483 | if item.endswith('~') or item.endswith('#'): | |
484 | continue | |
485 | name = OS.path.join(thing, item) | |
486 | if not OS.path.isfile(name): | |
487 | continue | |
488 | yield file(name) | |
489 | else: | |
490 | yield file(thing) | |
491 | ||
492 | def parse_options(argv = argv): | |
493 | """ | |
494 | Parse command-line options, returning a pair (OPTS, ARGS). | |
495 | """ | |
496 | M.ego(argv[0]) | |
497 | op = OptionParser(usage = '%prog [-c CDB] INPUT...', | |
498 | version = '%%prog (tripe, version %s)' % VERSION) | |
499 | op.add_option('-c', '--cdb', metavar = 'CDB', | |
500 | dest = 'cdbfile', default = None, | |
501 | help = 'Compile output into a CDB file.') | |
502 | opts, args = op.parse_args(argv) | |
503 | return opts, args | |
504 | ||
505 | ###-------------------------------------------------------------------------- | |
506 | ### Main code. | |
507 | ||
508 | def getconf(args): | |
509 | """ | |
510 | Read the configuration files and return the accumulated result. | |
511 | ||
512 | We make sure that all hostnames have been properly resolved. | |
513 | """ | |
514 | conf = MyConfigParser() | |
515 | for f in inputiter(args): | |
b7e5aa06 | 516 | conf.parse(f) |
6005ef9b MW |
517 | conf.resolve() |
518 | return conf | |
519 | ||
520 | def output(conf, cdb): | |
521 | """ | |
522 | Output the configuration information CONF to the database CDB. | |
523 | ||
524 | This is where the special `user' and `auto' database entries get set. | |
525 | """ | |
526 | auto = [] | |
e3ec3a3a MW |
527 | for sec in sorted(conf.sections(), key = lambda sec: sec.name): |
528 | if sec.name.startswith('@'): | |
6005ef9b | 529 | continue |
e3ec3a3a MW |
530 | elif sec.name.startswith('$'): |
531 | label = sec.name | |
6005ef9b | 532 | else: |
e3ec3a3a | 533 | label = 'P%s' % sec.name |
fd1ba90c MW |
534 | try: a = sec.get('auto') |
535 | except MissingKeyException: pass | |
536 | else: | |
537 | if a in ('y', 'yes', 't', 'true', '1', 'on'): auto.append(sec.name) | |
538 | try: u = sec.get('user') | |
539 | except MissingKeyException: pass | |
540 | else: cdb.add('U%s' % u) | |
6090fc43 | 541 | url = M.URLEncode(semip = True) |
85341d9c | 542 | for key in sorted(sec.items()): |
6005ef9b | 543 | if not key.startswith('@'): |
6090fc43 | 544 | url.encode(key, sec.get(key)) |
6005ef9b MW |
545 | cdb.add(label, url.result) |
546 | cdb.add('%AUTO', ' '.join(auto)) | |
547 | cdb.finish() | |
548 | ||
549 | def main(): | |
550 | """Main program.""" | |
551 | opts, args = parse_options() | |
552 | if opts.cdbfile: | |
553 | cdb = CDB.cdbmake(opts.cdbfile, opts.cdbfile + '.new') | |
554 | else: | |
555 | cdb = CDBFake() | |
556 | conf = getconf(args[1:]) | |
557 | output(conf, cdb) | |
558 | ||
559 | if __name__ == '__main__': | |
560 | main() | |
561 | ||
562 | ###----- That's all, folks -------------------------------------------------- |