Mercurial > syslog2iptables
annotate src/syslog2iptables.cpp @ 72:ea7b7a0d0039
RHEL7 systemd and /var/run on tmpfs
| author | Carl Byington <carl@five-ten-sg.com> |
|---|---|
| date | Thu, 09 Feb 2017 12:58:21 -0800 |
| parents | f133196b8591 |
| children |
| 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 while (loader_run) { |
| 95 sleep(180); // look for modifications every 3 minutes | |
| 96 if (!loader_run) break; | |
| 97 CONFIG &dc = *config; | |
| 98 time_t then = dc.load_time; | |
| 99 struct stat st; | |
| 100 bool reload = false; | |
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101 for (string_set::const_iterator i=dc.config_files.begin(); i!=dc.config_files.end(); i++) { |
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102 const char *fn = *i; |
| 36 | 103 if (stat(fn, &st)) reload = true; // file disappeared |
| 104 else if (st.st_mtime > then) reload = true; // file modified | |
| 105 if (reload) break; | |
| 106 } | |
| 107 if (reload) { | |
| 108 CONFIG *newc = new_conf(); | |
| 109 if (newc) { | |
| 110 // replace the global config pointer | |
| 111 pthread_mutex_lock(&config_mutex); | |
| 112 config = newc; | |
| 113 pthread_mutex_unlock(&config_mutex); | |
| 114 } | |
| 115 else { | |
| 116 // failed to load new config | |
| 117 my_syslog("failed to load new configuration"); | |
| 118 system("echo 'failed to load new /etc/syslog2iptables.conf' | mail -s 'error in /etc/syslog2iptables.conf' root"); | |
| 119 // update the load time on the current config to prevent complaining every 3 minutes | |
| 120 dc.load_time = time(NULL); | |
| 121 } | |
| 122 } | |
| 123 } | |
| 124 return NULL; | |
| 1 | 125 } |
| 126 | |
| 127 | |
| 128 //////////////////////////////////////////////// | |
| 36 | 129 // The signal handler function for child process terminations, |
| 130 // called when a child terminates. | |
| 1 | 131 // |
| 36 | 132 void sigchld(int sig) |
| 1 | 133 { |
| 36 | 134 int status; |
| 135 /* Wait for any child without blocking */ | |
| 136 while (waitpid(-1, &status, WNOHANG) > 0) { | |
| 137 // ignore child exit status, we only do this to cleanup zombies | |
| 138 } | |
| 139 } | |
| 140 | |
| 141 | |
| 142 //////////////////////////////////////////////// | |
| 143 // The termination signal handler function, called to | |
| 144 // request termination of this process. | |
| 145 // | |
| 146 void sigterm(int sig) | |
| 147 { | |
| 148 loader_run = false; | |
| 149 signal(sig, SIG_DFL); // quit on repeated signals | |
| 1 | 150 } |
| 151 | |
| 152 | |
| 153 void usage(char *prog); | |
| 154 void usage(char *prog) | |
| 155 { | |
| 36 | 156 fprintf(stderr, "Usage: %s [-d [level]] [-c]\n", prog); |
| 157 fprintf(stderr, "-c will load and dump the config to stdout\n"); | |
| 158 fprintf(stderr, "-d will set the syslog message level, currently 0 to 3\n"); | |
| 5 | 159 } |
| 160 | |
| 161 | |
| 162 void worker(); | |
| 163 void worker() | |
| 164 { | |
| 36 | 165 time_t t = time(NULL); |
| 166 CONFIG *c; | |
| 167 pthread_mutex_lock(&config_mutex); | |
| 168 c = config; | |
| 169 c->reference_count++; | |
| 170 pthread_mutex_unlock(&config_mutex); | |
| 171 while (loader_run) { | |
| 172 if (c != config) { | |
| 173 pthread_mutex_lock(&config_mutex); | |
| 174 CONFIG *old = c; old->reference_count--; | |
| 175 c = config; c->reference_count++; | |
| 176 pthread_mutex_unlock(&config_mutex); | |
| 177 if (!old->reference_count) { | |
| 178 if (debug_syslog) { | |
| 179 char buf[maxlen]; | |
| 180 snprintf(buf, sizeof(buf), "freeing memory for old configuration generation %d", old->generation); | |
| 181 my_syslog(buf); | |
| 182 } | |
| 183 delete old; // destructor does all the work | |
| 184 } | |
| 185 } | |
| 186 c->read(); | |
| 187 c->sleep(2, t); | |
| 188 } | |
| 189 // worker shutting down, free all ip addresses | |
| 190 c->free_all(); | |
| 1 | 191 } |
| 192 | |
| 193 | |
| 194 int main(int argc, char *argv[]) | |
| 195 { | |
| 36 | 196 token_init(); |
| 197 bool check = false; | |
| 198 int c; | |
| 199 const char *args = "d:ch"; | |
| 200 extern char *optarg; | |
| 1 | 201 |
| 36 | 202 // Process command line options |
| 203 while ((c = getopt(argc, argv, args)) != -1) { | |
| 204 switch (c) { | |
| 205 case 'c': | |
| 206 check = true; | |
| 207 break; | |
| 1 | 208 |
| 36 | 209 case 'd': |
| 210 if (optarg == NULL || *optarg == '\0') debug_syslog = 1; | |
| 211 else debug_syslog = atoi(optarg); | |
| 212 break; | |
| 5 | 213 |
| 36 | 214 case 'h': |
| 215 default: | |
| 216 usage(argv[0]); | |
| 217 exit(EX_USAGE); | |
| 218 } | |
| 219 } | |
| 1 | 220 |
| 36 | 221 if (check) { |
| 222 use_syslog = false; | |
| 223 debug_syslog = 10; | |
| 224 config = new_conf(); | |
| 225 if (config) { | |
| 226 config->dump(); | |
| 227 delete config; | |
| 38 | 228 clear_strings(); // for valgrind checking |
| 36 | 229 return 0; |
| 230 } | |
| 231 else { | |
| 232 return 1; // config failed to load | |
| 233 } | |
| 234 } | |
| 1 | 235 |
| 36 | 236 // switch to background mode |
| 237 if (daemon(1,0) < 0) { | |
| 238 fprintf(stderr, "daemon() call failed\n"); | |
| 239 exit(EX_UNAVAILABLE); | |
| 240 } | |
| 1 | 241 |
| 36 | 242 // write the pid |
| 243 const char *pidpath = "/var/run/syslog2iptables.pid"; | |
| 244 unlink(pidpath); | |
| 245 FILE *f = fopen(pidpath, "w"); | |
| 246 if (f) { | |
| 1 | 247 #ifdef linux |
| 36 | 248 // from a comment in the DCC source code: |
| 249 // Linux threads are broken. Signals given the | |
| 250 // original process are delivered to only the | |
| 251 // thread that happens to have that PID. The | |
| 252 // sendmail libmilter thread that needs to hear | |
| 253 // SIGINT and other signals does not, and that breaks | |
| 254 // scripts that need to stop milters. | |
| 255 // However, signaling the process group works. | |
| 256 fprintf(f, "-%d\n", (u_int)getpgrp()); | |
| 1 | 257 #else |
| 36 | 258 fprintf(f, "%d\n", (u_int)getpid()); |
| 1 | 259 #endif |
| 36 | 260 fclose(f); |
| 261 } | |
| 1 | 262 |
| 36 | 263 // setup signal handler for termination signals |
| 264 signal(SIGHUP, sigterm); | |
| 265 signal(SIGTERM, sigterm); | |
| 266 signal(SIGINT, sigterm); | |
| 1 | 267 |
| 36 | 268 // initialize the thread sync objects |
| 269 pthread_mutex_init(&config_mutex, 0); | |
| 270 pthread_mutex_init(&syslog_mutex, 0); | |
| 271 | |
| 272 // load the initial config | |
| 273 config = new_conf(); | |
| 274 if (!config) { | |
| 275 my_syslog("failed to load initial configuration, quitting"); | |
| 276 exit(1); | |
| 277 } | |
| 1 | 278 |
| 36 | 279 // setup sigchld handler to prevent zombies |
| 280 struct sigaction act; | |
| 281 act.sa_handler = sigchld; // Assign sig_chld as our SIGCHLD handler | |
| 282 sigemptyset(&act.sa_mask); // We don't want to block any other signals in this example | |
| 283 act.sa_flags = SA_NOCLDSTOP; // only want children that have terminated | |
| 284 if (sigaction(SIGCHLD, &act, NULL) < 0) { | |
| 285 my_syslog("failed to setup SIGCHLD handler"); | |
| 286 exit(1); | |
| 287 } | |
| 2 | 288 |
| 36 | 289 // only create threads after the fork() in daemon |
| 290 pthread_t tid; | |
| 291 if (pthread_create(&tid, 0, config_loader, 0)) | |
| 292 my_syslog("failed to create config loader thread"); | |
| 293 if (pthread_detach(tid)) | |
| 294 my_syslog("failed to detach config loader thread"); | |
| 1 | 295 |
| 36 | 296 worker(); |
| 40 | 297 if (config) delete config; // for valgrind checking |
| 39 | 298 clear_strings(); // for valgrind checking |
| 5 | 299 |
| 36 | 300 return EXIT_SUCCESS; |
| 1 | 301 } |