Mercurial > syslog2iptables
annotate src/syslog2iptables.cpp @ 56:73dd2daeaf8e stable-1-0-13-2
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| author | Carl Byington <carl@five-ten-sg.com> |
|---|---|
| date | Wed, 17 Aug 2011 10:12:16 -0700 |
| parents | ba0259c9e411 |
| children | f133196b8591 |
| rev | line source |
|---|---|
| 36 | 1 /* |
| 2 | |
| 3 Copyright (c) 2007 Carl Byington - 510 Software Group, released under | |
| 4 the GPL version 3 or any later version at your choice available at | |
| 5 http://www.gnu.org/licenses/gpl-3.0.txt | |
| 6 | |
| 7 */ | |
| 8 | |
| 1 | 9 |
| 5 | 10 // debug levels: |
| 11 // 4 - show syslog lines that match regex | |
| 20 | 12 // 3 - show addresses being dropped/released from the filter |
| 10 | 13 // 2 - show files open/close |
| 5 | 14 // 1 - show config files loading |
| 1 | 15 |
| 9 | 16 #include "includes.h" |
| 1 | 17 #include <iostream> |
| 18 #include <cstdlib> | |
| 19 #include <errno.h> | |
| 20 #include <sysexits.h> | |
| 21 #include <pthread.h> | |
| 22 #include <syslog.h> | |
| 36 | 23 #include <sys/wait.h> /* header for waitpid() and various macros */ |
| 24 #include <signal.h> /* header for signal functions */ | |
| 1 | 25 |
|
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26 #ifndef HAVE_DAEMON |
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27 #include "daemon.h" |
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28 #include "daemon.c" |
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29 #endif |
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30 |
| 2 | 31 extern "C" { |
| 36 | 32 void sigchld(int sig); |
| 33 void sigterm(int sig); | |
| 2 | 34 } |
| 1 | 35 int debug_syslog = 0; |
| 36 bool syslog_opened = false; | |
| 36 | 37 bool use_syslog = true; // false to printf |
| 38 bool loader_run = true; // used to stop the config loader thread | |
| 39 CONFIG *config = NULL; // protected by the config_mutex | |
| 40 int generation = 0; // protected by the config_mutex | |
| 41 const int maxlen = 1000; // used for snprintf buffers | |
| 1 | 42 |
| 43 pthread_mutex_t config_mutex; | |
| 44 pthread_mutex_t syslog_mutex; | |
| 45 | |
| 46 | |
| 47 //////////////////////////////////////////////// | |
| 48 // syslog a message | |
| 49 // | |
|
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50 void my_syslog(const char *text) { |
| 36 | 51 if (use_syslog) { |
| 52 pthread_mutex_lock(&syslog_mutex); | |
| 53 if (!syslog_opened) { | |
| 54 openlog("syslog2iptables", LOG_PID, LOG_AUTHPRIV); | |
| 55 syslog_opened = true; | |
| 56 } | |
| 57 syslog(LOG_NOTICE, "%s", text); | |
| 58 pthread_mutex_unlock(&syslog_mutex); | |
| 59 } | |
| 60 else { | |
| 61 printf("%s\n", text); | |
| 62 } | |
| 1 | 63 } |
| 64 | |
| 65 //////////////////////////////////////////////// | |
| 36 | 66 // reload the config |
| 1 | 67 // |
| 68 CONFIG* new_conf(); | |
| 69 CONFIG* new_conf() { | |
| 36 | 70 CONFIG *newc = new CONFIG; |
| 71 pthread_mutex_lock(&config_mutex); | |
| 72 newc->generation = generation++; | |
| 73 pthread_mutex_unlock(&config_mutex); | |
| 74 if (debug_syslog) { | |
| 75 char buf[maxlen]; | |
| 76 snprintf(buf, sizeof(buf), "loading configuration generation %d", newc->generation); | |
| 77 my_syslog(buf); | |
| 78 } | |
| 79 if (load_conf(*newc, "syslog2iptables.conf")) { | |
| 80 newc->load_time = time(NULL); | |
| 81 return newc; | |
| 82 } | |
| 83 delete newc; | |
| 84 return NULL; | |
| 1 | 85 } |
| 86 | |
| 87 | |
| 88 //////////////////////////////////////////////// | |
| 36 | 89 // thread to watch the old config files for changes |
| 90 // and reload when needed. | |
| 1 | 91 // |
| 92 void* config_loader(void *arg); | |
| 93 void* config_loader(void *arg) { | |
| 36 | 94 typedef set<CONFIG *> configp_set; |
| 95 while (loader_run) { | |
| 96 sleep(180); // look for modifications every 3 minutes | |
| 97 if (!loader_run) break; | |
| 98 CONFIG &dc = *config; | |
| 99 time_t then = dc.load_time; | |
| 100 struct stat st; | |
| 101 bool reload = false; | |
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102 for (string_set::const_iterator i=dc.config_files.begin(); i!=dc.config_files.end(); i++) { |
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103 const char *fn = *i; |
| 36 | 104 if (stat(fn, &st)) reload = true; // file disappeared |
| 105 else if (st.st_mtime > then) reload = true; // file modified | |
| 106 if (reload) break; | |
| 107 } | |
| 108 if (reload) { | |
| 109 CONFIG *newc = new_conf(); | |
| 110 if (newc) { | |
| 111 // replace the global config pointer | |
| 112 pthread_mutex_lock(&config_mutex); | |
| 113 config = newc; | |
| 114 pthread_mutex_unlock(&config_mutex); | |
| 115 } | |
| 116 else { | |
| 117 // failed to load new config | |
| 118 my_syslog("failed to load new configuration"); | |
| 119 system("echo 'failed to load new /etc/syslog2iptables.conf' | mail -s 'error in /etc/syslog2iptables.conf' root"); | |
| 120 // update the load time on the current config to prevent complaining every 3 minutes | |
| 121 dc.load_time = time(NULL); | |
| 122 } | |
| 123 } | |
| 124 } | |
| 125 return NULL; | |
| 1 | 126 } |
| 127 | |
| 128 | |
| 129 //////////////////////////////////////////////// | |
| 36 | 130 // The signal handler function for child process terminations, |
| 131 // called when a child terminates. | |
| 1 | 132 // |
| 36 | 133 void sigchld(int sig) |
| 1 | 134 { |
| 36 | 135 int status; |
| 136 /* Wait for any child without blocking */ | |
| 137 while (waitpid(-1, &status, WNOHANG) > 0) { | |
| 138 // ignore child exit status, we only do this to cleanup zombies | |
| 139 } | |
| 140 } | |
| 141 | |
| 142 | |
| 143 //////////////////////////////////////////////// | |
| 144 // The termination signal handler function, called to | |
| 145 // request termination of this process. | |
| 146 // | |
| 147 void sigterm(int sig) | |
| 148 { | |
| 149 loader_run = false; | |
| 150 signal(sig, SIG_DFL); // quit on repeated signals | |
| 1 | 151 } |
| 152 | |
| 153 | |
| 154 void usage(char *prog); | |
| 155 void usage(char *prog) | |
| 156 { | |
| 36 | 157 fprintf(stderr, "Usage: %s [-d [level]] [-c]\n", prog); |
| 158 fprintf(stderr, "-c will load and dump the config to stdout\n"); | |
| 159 fprintf(stderr, "-d will set the syslog message level, currently 0 to 3\n"); | |
| 5 | 160 } |
| 161 | |
| 162 | |
| 163 void worker(); | |
| 164 void worker() | |
| 165 { | |
| 36 | 166 time_t t = time(NULL); |
| 167 CONFIG *c; | |
| 168 pthread_mutex_lock(&config_mutex); | |
| 169 c = config; | |
| 170 c->reference_count++; | |
| 171 pthread_mutex_unlock(&config_mutex); | |
| 172 while (loader_run) { | |
| 173 if (c != config) { | |
| 174 pthread_mutex_lock(&config_mutex); | |
| 175 CONFIG *old = c; old->reference_count--; | |
| 176 c = config; c->reference_count++; | |
| 177 pthread_mutex_unlock(&config_mutex); | |
| 178 if (!old->reference_count) { | |
| 179 if (debug_syslog) { | |
| 180 char buf[maxlen]; | |
| 181 snprintf(buf, sizeof(buf), "freeing memory for old configuration generation %d", old->generation); | |
| 182 my_syslog(buf); | |
| 183 } | |
| 184 delete old; // destructor does all the work | |
| 185 } | |
| 186 } | |
| 187 c->read(); | |
| 188 c->sleep(2, t); | |
| 189 } | |
| 190 // worker shutting down, free all ip addresses | |
| 191 c->free_all(); | |
| 1 | 192 } |
| 193 | |
| 194 | |
| 195 int main(int argc, char *argv[]) | |
| 196 { | |
| 36 | 197 token_init(); |
| 198 bool check = false; | |
| 199 int c; | |
| 200 const char *args = "d:ch"; | |
| 201 extern char *optarg; | |
| 1 | 202 |
| 36 | 203 // Process command line options |
| 204 while ((c = getopt(argc, argv, args)) != -1) { | |
| 205 switch (c) { | |
| 206 case 'c': | |
| 207 check = true; | |
| 208 break; | |
| 1 | 209 |
| 36 | 210 case 'd': |
| 211 if (optarg == NULL || *optarg == '\0') debug_syslog = 1; | |
| 212 else debug_syslog = atoi(optarg); | |
| 213 break; | |
| 5 | 214 |
| 36 | 215 case 'h': |
| 216 default: | |
| 217 usage(argv[0]); | |
| 218 exit(EX_USAGE); | |
| 219 } | |
| 220 } | |
| 1 | 221 |
| 36 | 222 if (check) { |
| 223 use_syslog = false; | |
| 224 debug_syslog = 10; | |
| 225 config = new_conf(); | |
| 226 if (config) { | |
| 227 config->dump(); | |
| 228 delete config; | |
| 38 | 229 clear_strings(); // for valgrind checking |
| 36 | 230 return 0; |
| 231 } | |
| 232 else { | |
| 233 return 1; // config failed to load | |
| 234 } | |
| 235 } | |
| 1 | 236 |
| 36 | 237 // switch to background mode |
| 238 if (daemon(1,0) < 0) { | |
| 239 fprintf(stderr, "daemon() call failed\n"); | |
| 240 exit(EX_UNAVAILABLE); | |
| 241 } | |
| 1 | 242 |
| 36 | 243 // write the pid |
| 244 const char *pidpath = "/var/run/syslog2iptables.pid"; | |
| 245 unlink(pidpath); | |
| 246 FILE *f = fopen(pidpath, "w"); | |
| 247 if (f) { | |
| 1 | 248 #ifdef linux |
| 36 | 249 // from a comment in the DCC source code: |
| 250 // Linux threads are broken. Signals given the | |
| 251 // original process are delivered to only the | |
| 252 // thread that happens to have that PID. The | |
| 253 // sendmail libmilter thread that needs to hear | |
| 254 // SIGINT and other signals does not, and that breaks | |
| 255 // scripts that need to stop milters. | |
| 256 // However, signaling the process group works. | |
| 257 fprintf(f, "-%d\n", (u_int)getpgrp()); | |
| 1 | 258 #else |
| 36 | 259 fprintf(f, "%d\n", (u_int)getpid()); |
| 1 | 260 #endif |
| 36 | 261 fclose(f); |
| 262 } | |
| 1 | 263 |
| 36 | 264 // setup signal handler for termination signals |
| 265 signal(SIGHUP, sigterm); | |
| 266 signal(SIGTERM, sigterm); | |
| 267 signal(SIGINT, sigterm); | |
| 1 | 268 |
| 36 | 269 // initialize the thread sync objects |
| 270 pthread_mutex_init(&config_mutex, 0); | |
| 271 pthread_mutex_init(&syslog_mutex, 0); | |
| 272 | |
| 273 // load the initial config | |
| 274 config = new_conf(); | |
| 275 if (!config) { | |
| 276 my_syslog("failed to load initial configuration, quitting"); | |
| 277 exit(1); | |
| 278 } | |
| 1 | 279 |
| 36 | 280 // setup sigchld handler to prevent zombies |
| 281 struct sigaction act; | |
| 282 act.sa_handler = sigchld; // Assign sig_chld as our SIGCHLD handler | |
| 283 sigemptyset(&act.sa_mask); // We don't want to block any other signals in this example | |
| 284 act.sa_flags = SA_NOCLDSTOP; // only want children that have terminated | |
| 285 if (sigaction(SIGCHLD, &act, NULL) < 0) { | |
| 286 my_syslog("failed to setup SIGCHLD handler"); | |
| 287 exit(1); | |
| 288 } | |
| 2 | 289 |
| 36 | 290 // only create threads after the fork() in daemon |
| 291 pthread_t tid; | |
| 292 if (pthread_create(&tid, 0, config_loader, 0)) | |
| 293 my_syslog("failed to create config loader thread"); | |
| 294 if (pthread_detach(tid)) | |
| 295 my_syslog("failed to detach config loader thread"); | |
| 1 | 296 |
| 36 | 297 worker(); |
| 40 | 298 if (config) delete config; // for valgrind checking |
| 39 | 299 clear_strings(); // for valgrind checking |
| 5 | 300 |
| 36 | 301 return EXIT_SUCCESS; |
| 1 | 302 } |