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