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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: fw.c,v 1.6 1999/12/22 15:44:10 mdw Exp $ |
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4 | * |
5 | * Port forwarding thingy |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the `fw' port forwarder. |
13 | * |
14 | * `fw' is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * `fw' is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with `fw'; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: fw.c,v $ |
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32 | * Revision 1.6 1999/12/22 15:44:10 mdw |
33 | * Make syslog a separate option, and do it better. |
34 | * |
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35 | * Revision 1.5 1999/10/22 22:47:50 mdw |
36 | * Grammar changes. Also, don't enable SIGINT if it's currently ignored. |
37 | * |
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38 | * Revision 1.4 1999/10/10 16:46:12 mdw |
39 | * New resolver to initialize. Also, include options for grammar and |
40 | * options references. |
41 | * |
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42 | * Revision 1.3 1999/07/26 23:30:42 mdw |
43 | * Major reconstruction work for new design. |
44 | * |
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45 | * Revision 1.2 1999/07/03 13:55:17 mdw |
46 | * Various changes. Add configuration grammar to help text. Change to |
47 | * root directory and open syslog when forking into background. |
48 | * |
49 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
50 | * Initial revision. |
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51 | * |
52 | */ |
53 | |
54 | /*----- Header files ------------------------------------------------------*/ |
55 | |
56 | #include "config.h" |
57 | |
58 | #include <ctype.h> |
59 | #include <errno.h> |
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60 | #include <signal.h> |
61 | #include <stdarg.h> |
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62 | #include <stdio.h> |
63 | #include <stdlib.h> |
64 | #include <string.h> |
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65 | #include <time.h> |
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66 | |
67 | #include <unistd.h> |
68 | #include <syslog.h> |
69 | |
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70 | #include <mLib/bres.h> |
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71 | #include <mLib/dstr.h> |
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72 | #include <mLib/mdwopt.h> |
73 | #include <mLib/quis.h> |
74 | #include <mLib/report.h> |
75 | #include <mLib/sel.h> |
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76 | #include <mLib/sig.h> |
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77 | #include <mLib/sub.h> |
78 | |
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79 | #include "conf.h" |
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80 | #include "endpt.h" |
81 | #include "exec.h" |
82 | #include "fattr.h" |
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83 | #include "fw.h" |
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84 | #include "scan.h" |
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85 | #include "source.h" |
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86 | |
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87 | /*----- Global variables --------------------------------------------------*/ |
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88 | |
89 | sel_state *sel; /* Multiplexor for nonblocking I/O */ |
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90 | |
91 | /*----- Static variables --------------------------------------------------*/ |
92 | |
93 | static unsigned flags = 0; /* Global state flags */ |
94 | static unsigned active = 0; /* Number of active things */ |
95 | |
96 | #define FW_SYSLOG 1u |
97 | #define FW_QUIET 2u |
98 | #define FW_SET 4u |
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99 | |
100 | /*----- Main code ---------------------------------------------------------*/ |
101 | |
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102 | /* --- @fw_log@ --- * |
103 | * |
104 | * Arguments: @time_t t@ = when the connection occurred or (@-1@) |
105 | * @const char *fmt@ = format string to fill in |
106 | * @...@ = other arguments |
107 | * |
108 | * Returns: --- |
109 | * |
110 | * Use: Logs a connection. |
111 | */ |
112 | |
113 | void fw_log(time_t t, const char *fmt, ...) |
114 | { |
115 | struct tm *tm; |
116 | dstr d = DSTR_INIT; |
117 | va_list ap; |
118 | |
119 | if (flags & FW_QUIET) |
120 | return; |
121 | |
122 | if (t == -1) |
123 | t = time(0); |
124 | tm = localtime(&t); |
125 | DENSURE(&d, 64); |
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126 | d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S ", tm); |
61e3dbdf |
127 | va_start(ap, fmt); |
128 | dstr_vputf(&d, fmt, ap); |
129 | va_end(ap); |
130 | if (flags & FW_SYSLOG) |
131 | syslog(LOG_NOTICE, "%s", d.buf); |
132 | else { |
133 | DPUTC(&d, '\n'); |
134 | dstr_write(&d, stderr); |
135 | } |
136 | DDESTROY(&d); |
137 | } |
138 | |
139 | /* --- @fw_inc@, @fw_dec@ --- * |
140 | * |
141 | * Arguments: --- |
142 | * |
143 | * Returns: --- |
144 | * |
145 | * Use: Increments or decrements the active thing count. `fw' won't |
146 | * quit while there are active things. |
147 | */ |
148 | |
149 | void fw_inc(void) { flags |= FW_SET; active++; } |
150 | void fw_dec(void) { if (active) active--; } |
151 | |
152 | /* --- @fw_exit@ --- * |
153 | * |
154 | * Arguments: --- |
155 | * |
156 | * Returns: --- |
157 | * |
158 | * Use: Exits when appropriate. |
159 | */ |
160 | |
161 | static void fw_exit(void) |
162 | { |
163 | endpt_killall(); |
164 | source_killall(); |
165 | } |
166 | |
167 | /* --- @fw_tidy@ --- * |
168 | * |
169 | * Arguments: @int n@ = signal number |
170 | * @void *p@ = an uninteresting argument |
171 | * |
172 | * Returns: --- |
173 | * |
174 | * Use: Handles various signals and causes a clean tidy-up. |
175 | */ |
176 | |
177 | static void fw_tidy(int n, void *p) |
178 | { |
179 | const char *sn = "unexpected signal (bug!)"; |
180 | if (n == SIGTERM) |
181 | sn = "SIGTERM"; |
182 | else if (n == SIGINT) |
183 | sn = "SIGINT"; |
184 | |
185 | fw_log(-1, "closing down on %s", sn); |
186 | fw_exit(); |
187 | } |
188 | |
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189 | /* --- Standard GNU help options --- */ |
190 | |
191 | static void version(FILE *fp) |
192 | { |
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193 | pquis(fp, "$ version " VERSION "\n"); |
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194 | } |
195 | |
196 | static void usage(FILE *fp) |
197 | { |
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198 | pquis(fp, "Usage: $ [-dql] [-f file] [config statements...]\n"); |
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199 | } |
200 | |
201 | static void help(FILE *fp) |
202 | { |
203 | version(fp); |
204 | fputc('\n', fp); |
205 | usage(fp); |
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206 | pquis(fp, "\n\ |
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207 | An excessively full-featured port-forwarder, which subsumes large chunks\n\ |
208 | of the functionality of inetd, netcat, and normal cat. Options available\n\ |
209 | are:\n\ |
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210 | \n\ |
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211 | -h, --help Display this help message.\n\ |
212 | -v, --version Display the program's version number.\n\ |
213 | -u, --usage Display a terse usage summary.\n\ |
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214 | \n\ |
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215 | -g, --grammar Show a summary of the configuration language.\n\ |
216 | -o, --options Show a summary of the source and target options.\n\ |
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217 | \n\ |
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218 | -f, --file=FILE Read configuration from a file.\n\ |
219 | -q, --quiet Don't emit any logging information.\n\ |
220 | -d, --daemon Fork into background after initializing.\n\ |
221 | -l, --syslog Send log output to the system logger.\n\ |
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222 | \n\ |
223 | Configuration may be supplied in one or more configuration files, or on\n\ |
224 | the command line (or both). If no `-f' option is present, and no\n\ |
225 | configuration is given on the command line, the standard input stream is\n\ |
226 | read.\n\ |
227 | \n\ |
228 | Configuration is free-form. Comments begin with a `#' character and\n\ |
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229 | continue to the end of the line. Each command line argument is considered\n\ |
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230 | to be a separate line.\n\ |
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231 | \n\ |
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232 | The grammar is fairly complicated. For a summary, run `$ --grammar'.\n\ |
233 | For a summary of the various options, run `$ --options'.\n\ |
234 | "); |
235 | } |
236 | |
237 | /* --- Other helpful options --- */ |
238 | |
239 | static void grammar(FILE *fp) |
240 | { |
241 | version(fp); |
242 | pquis(fp, "\n\ |
243 | Grammar summary\n\ |
244 | \n\ |
245 | Basic syntax\n\ |
246 | file ::= empty | file stmt [`;']\n\ |
247 | stmt ::= option-stmt | fw-stmt\n\ |
248 | fw-stmt ::= `fw' source options [`to'|`->'] target options\n\ |
249 | options ::= `{' option-seq `}'\n\ |
250 | option-seq ::= empty | option-stmt [`;'] option-seq\n\ |
251 | \n\ |
252 | Option syntax\n\ |
253 | option-stmt ::= q-option\n\ |
254 | q-option ::= option\n\ |
255 | | prefix `.' q-option\n\ |
256 | | prefix `{' option-seq `}'\n\ |
257 | prefix ::= word\n\ |
258 | \n\ |
259 | File source and target\n\ |
260 | source ::= file\n\ |
261 | target ::= file\n\ |
262 | file ::= `file' [`.'] fspec [`,' fspec]\n\ |
263 | fspec ::= fd-spec | name-spec | null-spec\n\ |
264 | fd-spec ::= [[`:']`fd'[`:']] number|`stdin'|`stdout'\n\ |
265 | name-spec ::= [[`:']`file'[`:']] file-name\n\ |
266 | file-name ::= path-seq | [ path-seq ]\n\ |
267 | path-seq ::= path-elt | path-seq path-elt\n\ |
268 | path-elt ::= `/' | word\n\ |
269 | null-spec ::= [`:']`null'[`:']\n\ |
270 | \n\ |
271 | Exec source and target\n\ |
272 | source ::= exec\n\ |
273 | target ::= exec\n\ |
274 | exec ::= `exec' [`.'] cmd-spec\n\ |
275 | cmd-spec ::= shell-cmd | [prog-name] `[' argv0 arg-seq `]'\n\ |
276 | arg-seq ::= word | arg-seq word\n\ |
277 | shell-cmd ::= word\n\ |
278 | argv0 ::= word\n\ |
279 | \n\ |
280 | Socket source and target\n\ |
281 | source ::= socket-source\n\ |
282 | target ::= socket-target\n\ |
283 | socket-source ::= [`socket'[`.']] [[`:']addr-type[`:']] source-addr\n\ |
284 | socket-target ::= [`socket'[`.']] [[`:']addr-type[`:']] target-addr\n\ |
285 | \n\ |
286 | inet-source-addr ::= [port] port\n\ |
287 | inet-target-addr ::= address [`:'] port\n\ |
288 | address ::= addr-elt | address addr-elt\n\ |
289 | addr-elt ::= `.' | word\n\ |
290 | \n\ |
291 | unix-source-addr ::= file-name\n\ |
292 | unix-target-addr ::= file-name\n\ |
293 | "); |
294 | } |
295 | |
296 | static void options(FILE *fp) |
297 | { |
298 | version(fp); |
299 | pquis(fp, "\n\ |
300 | Options summary\n\ |
301 | \n\ |
302 | File attributes (`fattr')\n\ |
303 | prefix.fattr.mode [=] mode\n\ |
304 | prefix.fattr.owner [=] user\n\ |
305 | prefix.fattr.group [=] group\n\ |
306 | \n\ |
307 | File options\n\ |
308 | file.create [=] yes|no\n\ |
309 | file.open [=] no|truncate|append\n\ |
310 | file.fattr.*\n\ |
311 | \n\ |
312 | Exec options\n\ |
313 | exec.logging [=] yes|no\n\ |
314 | exec.dir [=] file-name\n\ |
315 | exec.root [=] file-name\n\ |
316 | exec.user [=] user\n\ |
317 | exec.group [=] group\n\ |
318 | exec.rlimit.limit[.hard|.soft] [=] value\n\ |
319 | exec.env.clear\n\ |
320 | exec.env.unset var\n\ |
321 | exec.env.[set] var [=] value\n\ |
322 | \n\ |
323 | Socket options\n\ |
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324 | socket.conn [=] number|unlimited|one-shot\n\ |
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325 | socket.logging [=] yes|no\n\ |
326 | socket.inet.[allow|deny] [from] address [/ address]\n\ |
327 | socket.unix.fattr.*\n\ |
328 | "); |
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329 | } |
330 | |
331 | /* --- @main@ --- * |
332 | * |
333 | * Arguments: @int argc@ = number of command line arguments |
334 | * @char *argv[]@ = vector of argument strings |
335 | * |
336 | * Returns: --- |
337 | * |
338 | * Use: Simple port-forwarding server. |
339 | */ |
340 | |
341 | int main(int argc, char *argv[]) |
342 | { |
343 | unsigned f = 0; |
344 | sel_state sst; |
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345 | sig s_term, s_int; |
346 | scanner sc; |
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347 | |
348 | enum { |
349 | f_bogus = 1, |
350 | f_file = 2, |
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351 | f_syslog = 4, |
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352 | f_fork = 8 |
353 | }; |
354 | |
355 | /* --- Initialize things --- */ |
356 | |
357 | ego(argv[0]); |
358 | sel = &sst; |
359 | sel_init(sel); |
360 | sub_init(); |
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361 | sig_init(sel); |
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362 | bres_init(sel); |
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363 | bres_exec(0); |
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364 | exec_init(); |
365 | fattr_init(&fattr_global); |
366 | scan_create(&sc); |
367 | |
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368 | /* --- Set up some signal handlers --- * |
369 | * |
370 | * Don't enable @SIGINT@ if the caller already disabled it. |
371 | */ |
372 | |
373 | { |
374 | struct sigaction sa; |
375 | |
376 | sig_add(&s_term, SIGTERM, fw_tidy, 0); |
377 | sigaction(SIGINT, 0, &sa); |
378 | if (sa.sa_handler != SIG_IGN) |
379 | sig_add(&s_int, SIGINT, fw_tidy, 0); |
380 | } |
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381 | |
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382 | atexit(fw_exit); |
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383 | |
384 | /* --- Parse command line options --- */ |
385 | |
386 | for (;;) { |
387 | static struct option opts[] = { |
388 | |
389 | /* --- Standard GNU help options --- */ |
390 | |
391 | { "help", 0, 0, 'h' }, |
392 | { "version", 0, 0, 'v' }, |
393 | { "usage", 0, 0, 'u' }, |
394 | |
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395 | /* --- Other help options --- */ |
396 | |
397 | { "grammar", 0, 0, 'g' }, |
398 | { "options", 0, 0, 'o' }, |
399 | |
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400 | /* --- Other useful arguments --- */ |
401 | |
402 | { "file", OPTF_ARGREQ, 0, 'f' }, |
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403 | { "fork", 0, 0, 'd' }, |
404 | { "daemon", 0, 0, 'd' }, |
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405 | { "syslog", 0, 0, 'l' }, |
406 | { "log", 0, 0, 'l' }, |
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407 | { "quiet", 0, 0, 'q' }, |
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408 | |
409 | /* --- Magic terminator --- */ |
410 | |
411 | { 0, 0, 0, 0 } |
412 | }; |
17be1d6b |
413 | int i = mdwopt(argc, argv, "+hvu go f:dl", opts, 0, 0, 0); |
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414 | |
415 | if (i < 0) |
416 | break; |
417 | switch (i) { |
418 | case 'h': |
419 | help(stdout); |
420 | exit(0); |
421 | break; |
422 | case 'v': |
423 | version(stdout); |
424 | exit(0); |
425 | break; |
426 | case 'u': |
427 | usage(stdout); |
428 | exit(0); |
429 | break; |
2d9ec601 |
430 | case 'g': |
431 | grammar(stdout); |
432 | exit(0); |
433 | break; |
434 | case 'o': |
435 | options(stdout); |
436 | exit(0); |
437 | break; |
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438 | case 'f': |
439 | if (strcmp(optarg, "-") == 0) |
440 | scan_add(&sc, scan_file(stdin, "<stdin>", SCF_NOCLOSE)); |
441 | else { |
442 | FILE *fp; |
443 | if ((fp = fopen(optarg, "r")) == 0) |
444 | die(1, "couldn't open file `%s': %s", optarg, strerror(errno)); |
445 | scan_add(&sc, scan_file(fp, optarg, 0)); |
446 | } |
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447 | f |= f_file; |
e82f7154 |
448 | break; |
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449 | case 'd': |
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450 | f |= f_fork; |
451 | break; |
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452 | case 'l': |
453 | f |= f_syslog; |
454 | break; |
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455 | case 'q': |
456 | flags |= FW_QUIET; |
457 | break; |
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458 | default: |
459 | f |= f_bogus; |
460 | break; |
461 | } |
462 | } |
463 | |
464 | if (f & f_bogus) { |
465 | usage(stderr); |
466 | exit(1); |
467 | } |
468 | |
469 | /* --- Deal with the remaining arguments --- */ |
470 | |
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471 | if (optind < argc) |
472 | scan_add(&sc, scan_argv(argv + optind)); |
473 | else if (f & f_file) |
474 | /* Cool */; |
475 | else if (!isatty(STDIN_FILENO)) |
476 | scan_add(&sc, scan_file(stdin, "<stdin>", SCF_NOCLOSE)); |
477 | else { |
478 | moan("no configuration given and stdin is a terminal."); |
479 | moan("type `%s --help' for usage information.", QUIS); |
480 | exit(1); |
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481 | } |
482 | |
61e3dbdf |
483 | /* --- Parse the configuration now gathered --- */ |
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484 | |
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485 | conf_parse(&sc); |
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486 | |
487 | /* --- Fork into the background --- */ |
488 | |
489 | if (f & f_fork) { |
490 | pid_t kid; |
491 | |
492 | kid = fork(); |
493 | if (kid == -1) |
494 | die(1, "couldn't fork: %s", strerror(errno)); |
495 | if (kid != 0) |
496 | _exit(0); |
497 | |
498 | close(0); close(1); close(2); |
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499 | chdir("/"); |
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500 | setsid(); |
501 | |
502 | kid = fork(); |
503 | if (kid != 0) |
504 | _exit(0); |
17be1d6b |
505 | } |
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506 | |
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507 | if (f & f_syslog) { |
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508 | flags |= FW_SYSLOG; |
509 | openlog(QUIS, 0, LOG_DAEMON); |
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510 | } |
511 | |
512 | /* --- Let rip --- */ |
513 | |
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514 | if (!(flags & FW_SET)) |
515 | moan("nothing to do!"); |
516 | signal(SIGPIPE, SIG_IGN); |
517 | while (active) |
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518 | sel_select(sel); |
519 | return (0); |
520 | } |
521 | |
522 | /*----- That's all, folks -------------------------------------------------*/ |