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comparison src/sm-archive.cpp @ 0:616666e2f34c

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initial version
author carl
date Fri, 10 Mar 2006 10:30:08 -0800
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children 32b57406b656
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-1:000000000000 0:616666e2f34c
1 /*
2
3 Copyright (c) 2004, 2005 Carl Byington - 510 Software Group, released
4 under the GPL version 2 or any later version at your choice available at
5 http://www.fsf.org/licenses/gpl.txt
6
7 Based on a sample milter Copyright (c) 2000-2003 Sendmail, Inc. and its
8 suppliers. Inspired by the DCC by Rhyolite Software
9
10 -p port The port through which the MTA will connect to this milter.
11 -t sec The timeout value.
12 -c Check the config, and print a copy to stdout. Don't start the
13 milter or do anything with the socket.
14 -d increase debug level
15
16 */
17
18
19 // from sendmail sample
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <errno.h>
23 #include <sysexits.h>
24 #include <unistd.h>
25
26 // needed for socket io
27 #include <sys/ioctl.h>
28 #include <net/if.h>
29 #include <arpa/inet.h>
30 #include <netinet/in.h>
31 #include <netinet/tcp.h>
32 #include <netdb.h>
33 #include <sys/socket.h>
34 #include <sys/un.h>
35
36 // needed for thread
37 #include <pthread.h>
38
39 // needed for std c++ collections
40 #include <set>
41 #include <map>
42 #include <list>
43
44 // for the dns resolver
45 #include <netinet/in.h>
46 #include <arpa/nameser.h>
47 #include <resolv.h>
48
49 // misc stuff needed here
50 #include <ctype.h>
51 #include <syslog.h>
52 #include <pwd.h>
53 #include <sys/wait.h> /* header for waitpid() and various macros */
54 #include <signal.h> /* header for signal functions */
55
56 #include "includes.h"
57
58 static char* dnsbl_version="$Id$";
59
60
61 extern "C" {
62 #include "libmilter/mfapi.h"
63 sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr);
64 sfsistat mlfi_envfrom(SMFICTX *ctx, char **argv);
65 sfsistat mlfi_envrcpt(SMFICTX *ctx, char **argv);
66 sfsistat mlfi_eom(SMFICTX *ctx);
67 sfsistat mlfi_abort(SMFICTX *ctx);
68 sfsistat mlfi_close(SMFICTX *ctx);
69 void sig_chld(int signo);
70 }
71
72 int debug_syslog = 0;
73 bool syslog_opened = false;
74 bool use_syslog = true; // false to printf
75 bool loader_run = true; // used to stop the config loader thread
76 CONFIG *config = NULL; // protected by the config_mutex
77 int generation = 0; // protected by the config_mutex
78 const int maxlen = 1000; // used for snprintf buffers
79
80 pthread_mutex_t config_mutex;
81 pthread_mutex_t syslog_mutex;
82
83
84 mlfiPriv::mlfiPriv() {
85 pthread_mutex_lock(&config_mutex);
86 pc = config;
87 pc->reference_count++;
88 pthread_mutex_unlock(&config_mutex);
89 mailaddr = NULL;
90 queueid = NULL;
91 processed_from = false;
92 }
93
94 mlfiPriv::~mlfiPriv() {
95 pthread_mutex_lock(&config_mutex);
96 pc->reference_count--;
97 pthread_mutex_unlock(&config_mutex);
98 reset(true);
99 }
100
101 void mlfiPriv::reset(bool final) {
102 processed_from = false;
103 if (mailaddr) free(mailaddr);
104 if (queueid) free(queueid);
105 if (!final) {
106 mailaddr = NULL;
107 queueid = NULL;
108 }
109 }
110
111 #define MLFIPRIV ((struct mlfiPriv *) smfi_getpriv(ctx))
112
113
114 ////////////////////////////////////////////////
115 // syslog a message
116 //
117 void my_syslog(mlfiPriv *priv, char *text) {
118 char buf[maxlen];
119 if (priv) {
120 snprintf(buf, sizeof(buf), "%s: %s", priv->queueid, text);
121 text = buf;
122 }
123 if (use_syslog) {
124 pthread_mutex_lock(&syslog_mutex);
125 if (!syslog_opened) {
126 openlog("dnsbl", LOG_PID, LOG_MAIL);
127 syslog_opened = true;
128 }
129 syslog(LOG_NOTICE, "%s", text);
130 pthread_mutex_unlock(&syslog_mutex);
131 }
132 else {
133 printf("%s \n", text);
134 }
135 }
136
137 void my_syslog(char *text) {
138 my_syslog(NULL, text);
139 }
140
141
142 ////////////////////////////////////////////////
143 // this email address is passed in from sendmail, and will
144 // always be enclosed in <>. It may have mixed case, just
145 // as the mail client sent it. We dup the string and convert
146 // the duplicate to lower case.
147 //
148 char *to_lower_string(char *email);
149 char *to_lower_string(char *email) {
150 int n = strlen(email)-2;
151 if (n < 1) return strdup(email);
152 char *key = strdup(email+1);
153 key[n] = '\0';
154 for (int i=0; i<n; i++) key[i] = tolower(key[i]);
155 return key;
156 }
157
158
159 ////////////////////////////////////////////////
160 // start of sendmail milter interfaces
161 //
162 sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr)
163 {
164 // allocate some private memory
165 mlfiPriv *priv = new mlfiPriv;
166 // save the private data
167 smfi_setpriv(ctx, (void*)priv);
168 // continue processing
169 return SMFIS_CONTINUE;
170 }
171
172 sfsistat mlfi_envfrom(SMFICTX *ctx, char **from)
173 {
174 mlfiPriv &priv = *MLFIPRIV;
175 priv.mailaddr = to_lower_string(from[0]);
176 return SMFIS_CONTINUE;
177 }
178
179 sfsistat mlfi_envrcpt(SMFICTX *ctx, char **rcpt)
180 {
181 mlfiPriv &priv = *MLFIPRIV;
182 CONFIG &dc = *priv.pc;
183 if (!priv.queueid) priv.queueid = strdup(smfi_getsymval(ctx, "i"));
184 char *rcptaddr = to_lower_string(rcpt[0]);
185 if (debug_syslog > 1) {
186 char msg[maxlen];
187 snprintf(msg, sizeof(msg), "from <%s> to <%s>", priv.mailaddr, rcptaddr);
188 my_syslog(&priv, msg);
189 }
190 char *target = dc.find_to(rcptaddr);
191 if (target) smfi_addrcpt(ctx, target);
192 free(rcptaddr);
193 if (!processed_from) {
194 target = dc.find_from(priv.mailaddr);
195 if (target) smfi_addrcpt(ctx, target);
196 processed_from = true;
197 }
198 return SMFIS_CONTINUE;
199 }
200
201 sfsistat mlfi_eom(SMFICTX *ctx)
202 {
203 // reset for a new message on the same connection
204 mlfi_abort(ctx);
205 return SMFIS_CONTINUE;
206 }
207
208 sfsistat mlfi_abort(SMFICTX *ctx)
209 {
210 mlfiPriv &priv = *MLFIPRIV;
211 if (!priv) return SMFIS_CONTINUE;
212 priv.reset();
213 return SMFIS_CONTINUE;
214 }
215
216 sfsistat mlfi_close(SMFICTX *ctx)
217 {
218 mlfiPriv *priv = MLFIPRIV;
219 if (!priv) return SMFIS_CONTINUE;
220 delete priv;
221 smfi_setpriv(ctx, NULL);
222 return SMFIS_CONTINUE;
223 }
224
225 struct smfiDesc smfilter =
226 {
227 "SM-ARCHIVE", // filter name
228 SMFI_VERSION, // version code -- do not change
229 SMFIF_ADDRCPT, // flags
230 mlfi_connect, // connection info filter
231 NULL, // SMTP HELO command filter
232 mlfi_envfrom, // envelope sender filter
233 mlfi_envrcpt, // envelope recipient filter
234 NULL, // header filter
235 NULL, // end of header
236 NULL, // body block filter
237 mlfi_eom, // end of message
238 mlfi_abort, // message aborted
239 mlfi_close, // connection cleanup
240 };
241
242
243 ////////////////////////////////////////////////
244 // reload the config
245 //
246 CONFIG* new_conf();
247 CONFIG* new_conf() {
248 CONFIG *newc = new CONFIG;
249 pthread_mutex_lock(&config_mutex);
250 newc->generation = generation++;
251 pthread_mutex_unlock(&config_mutex);
252 if (debug_syslog) {
253 char buf[maxlen];
254 snprintf(buf, sizeof(buf), "loading configuration generation %d", newc->generation);
255 my_syslog(buf);
256 }
257 if (load_conf(*newc, "dnsbl.conf")) {
258 newc->load_time = time(NULL);
259 return newc;
260 }
261 delete newc;
262 return NULL;
263 }
264
265
266 ////////////////////////////////////////////////
267 // thread to watch the old config files for changes
268 // and reload when needed. we also cleanup old
269 // configs whose reference count has gone to zero.
270 //
271 void* config_loader(void *arg);
272 void* config_loader(void *arg) {
273 typedef set<CONFIG *> configp_set;
274 configp_set old_configs;
275 while (loader_run) {
276 sleep(180); // look for modifications every 3 minutes
277 if (!loader_run) break;
278 CONFIG &dc = *config;
279 time_t then = dc.load_time;
280 struct stat st;
281 bool reload = false;
282 for (string_set::iterator i=dc.config_files.begin(); i!=dc.config_files.end(); i++) {
283 char *fn = *i;
284 if (stat(fn, &st)) reload = true; // file disappeared
285 else if (st.st_mtime > then) reload = true; // file modified
286 if (reload) break;
287 }
288 if (reload) {
289 CONFIG *newc = new_conf();
290 if (newc) {
291 // replace the global config pointer
292 pthread_mutex_lock(&config_mutex);
293 CONFIG *old = config;
294 config = newc;
295 pthread_mutex_unlock(&config_mutex);
296 if (old) old_configs.insert(old);
297 }
298 else {
299 // failed to load new config
300 my_syslog("failed to load new configuration");
301 system("echo 'failed to load new dnsbl configuration from /etc/dnsbl' | mail -s 'error in /etc/dnsbl configuration' root");
302 // update the load time on the current config to prevent complaining every 3 minutes
303 dc.load_time = time(NULL);
304 }
305 }
306 // now look for old configs with zero ref counts
307 for (configp_set::iterator i=old_configs.begin(); i!=old_configs.end(); ) {
308 CONFIG *old = *i;
309 if (!old->reference_count) {
310 if (debug_syslog) {
311 char buf[maxlen];
312 snprintf(buf, sizeof(buf), "freeing memory for old configuration generation %d", old->generation);
313 my_syslog(buf);
314 }
315 delete old; // destructor does all the work
316 old_configs.erase(i++);
317 }
318 else i++;
319 }
320 }
321 return NULL;
322 }
323
324
325 void usage(char *prog);
326 void usage(char *prog)
327 {
328 fprintf(stderr, "Usage: %s [-d [level]] [-c] -p sm-sock-addr [-t timeout]\n", prog);
329 fprintf(stderr, "where sm-sock-addr is for the connection to sendmail\n");
330 fprintf(stderr, " and should be one of\n");
331 fprintf(stderr, " inet:port@ip-address\n");
332 fprintf(stderr, " local:local-domain-socket-file-name\n");
333 fprintf(stderr, "-c will load and dump the config to stdout\n");
334 fprintf(stderr, "-d will set the syslog message level, currently 0 to 3\n");
335 }
336
337
338
339 void setup_socket(char *sock);
340 void setup_socket(char *sock) {
341 unlink(sock);
342 // sockaddr_un addr;
343 // memset(&addr, '\0', sizeof addr);
344 // addr.sun_family = AF_UNIX;
345 // strncpy(addr.sun_path, sock, sizeof(addr.sun_path)-1);
346 // int s = socket(AF_UNIX, SOCK_STREAM, 0);
347 // bind(s, (sockaddr*)&addr, sizeof(addr));
348 // close(s);
349 }
350
351
352 /*
353 * The signal handler function -- only gets called when a SIGCHLD
354 * is received, ie when a child terminates
355 */
356 void sig_chld(int signo)
357 {
358 int status;
359 /* Wait for any child without blocking */
360 while (waitpid(-1, &status, WNOHANG) > 0) {
361 // ignore child exit status, we only do this to cleanup zombies
362 }
363 }
364
365
366 int main(int argc, char**argv)
367 {
368 token_init();
369 bool check = false;
370 bool setconn = false;
371 int c;
372 const char *args = "p:t:d:ch";
373 extern char *optarg;
374
375 // Process command line options
376 while ((c = getopt(argc, argv, args)) != -1) {
377 switch (c) {
378 case 'p':
379 if (optarg == NULL || *optarg == '\0') {
380 fprintf(stderr, "Illegal sendmail socket: %s\n", optarg);
381 exit(EX_USAGE);
382 }
383 if (smfi_setconn(optarg) == MI_FAILURE) {
384 fprintf(stderr, "smfi_setconn failed\n");
385 exit(EX_SOFTWARE);
386 }
387 if (strncasecmp(optarg, "unix:", 5) == 0) setup_socket(optarg + 5);
388 else if (strncasecmp(optarg, "local:", 6) == 0) setup_socket(optarg + 6);
389 setconn = true;
390 break;
391
392 case 't':
393 if (optarg == NULL || *optarg == '\0') {
394 fprintf(stderr, "Illegal timeout: %s\n", optarg);
395 exit(EX_USAGE);
396 }
397 if (smfi_settimeout(atoi(optarg)) == MI_FAILURE) {
398 fprintf(stderr, "smfi_settimeout failed\n");
399 exit(EX_SOFTWARE);
400 }
401 break;
402
403 case 'c':
404 check = true;
405 break;
406
407 case 'd':
408 if (optarg == NULL || *optarg == '\0') debug_syslog = 1;
409 else debug_syslog = atoi(optarg);
410 break;
411
412 case 'h':
413 default:
414 usage(argv[0]);
415 exit(EX_USAGE);
416 }
417 }
418
419 if (check) {
420 use_syslog = false;
421 debug_syslog = 10;
422 CONFIG *conf = new_conf();
423 if (conf) {
424 conf->dump();
425 delete conf;
426 return 0;
427 }
428 else {
429 return 1; // config failed to load
430 }
431 }
432
433 if (!setconn) {
434 fprintf(stderr, "%s: Missing required -p argument\n", argv[0]);
435 usage(argv[0]);
436 exit(EX_USAGE);
437 }
438
439 if (smfi_register(smfilter) == MI_FAILURE) {
440 fprintf(stderr, "smfi_register failed\n");
441 exit(EX_UNAVAILABLE);
442 }
443
444 // switch to background mode
445 if (daemon(1,0) < 0) {
446 fprintf(stderr, "daemon() call failed\n");
447 exit(EX_UNAVAILABLE);
448 }
449
450 // write the pid
451 const char *pidpath = "/var/run/dnsbl.pid";
452 unlink(pidpath);
453 FILE *f = fopen(pidpath, "w");
454 if (f) {
455 #ifdef linux
456 // from a comment in the DCC source code:
457 // Linux threads are broken. Signals given the
458 // original process are delivered to only the
459 // thread that happens to have that PID. The
460 // sendmail libmilter thread that needs to hear
461 // SIGINT and other signals does not, and that breaks
462 // scripts that need to stop milters.
463 // However, signaling the process group works.
464 fprintf(f, "-%d\n", (u_int)getpgrp());
465 #else
466 fprintf(f, "%d\n", (u_int)getpid());
467 #endif
468 fclose(f);
469 }
470
471 // initialize the thread sync objects
472 pthread_mutex_init(&config_mutex, 0);
473 pthread_mutex_init(&syslog_mutex, 0);
474
475 // drop root privs
476 struct passwd *pw = getpwnam("sm-archive");
477 if (pw) {
478 if (setgid(pw->pw_gid) == -1) {
479 my_syslog("failed to switch to group dnsbl");
480 }
481 if (setuid(pw->pw_uid) == -1) {
482 my_syslog("failed to switch to user dnsbl");
483 }
484 }
485
486 // load the initial config
487 config = new_conf();
488 if (!config) {
489 my_syslog("failed to load initial configuration, quitting");
490 exit(1);
491 }
492
493 // only create threads after the fork() in daemon
494 pthread_t tid;
495 if (pthread_create(&tid, 0, config_loader, 0))
496 my_syslog("failed to create config loader thread");
497 if (pthread_detach(tid))
498 my_syslog("failed to detach config loader thread");
499
500 time_t starting = time(NULL);
501 int rc = smfi_main();
502 if ((rc != MI_SUCCESS) && (time(NULL) > starting+5*60)) {
503 my_syslog("trying to restart after smfi_main()");
504 loader_run = false; // eventually the config loader thread will terminate
505 execvp(argv[0], argv);
506 }
507 exit((rc == MI_SUCCESS) ? 0 : EX_UNAVAILABLE);
508 }
509