1 | /********************************************************************\
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2 |
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3 | Configuration server for the Evidence Control System
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4 |
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5 | - The configuration file is opened without buffering to catch changes
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6 | without closing/opening.
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7 | - The name of a configuration file can be given as command line argument
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8 | - If a configuration file change is detected through inotify, the service
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9 | "Config/ModifyTime" is updated with the current UNIX time to inform applications.
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10 | The initial value of the server is the last file modification time.
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11 | - The employed line buffer has conservatively at least the size of the
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12 | configuration file. If needed, it will be enlarged.
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13 |
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14 | Oliver Grimm, November 2009
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15 |
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16 | \********************************************************************/
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17 |
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18 | #define DEFAULT_CONFIG "../../config/Evidence.conf"
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19 | #define SERVER_NAME "Config"
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20 |
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21 | #include "Evidence.h"
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22 |
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23 | #include <ctype.h>
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24 | #include <sys/stat.h>
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25 | #include <sys/inotify.h>
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26 |
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27 | //
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28 | // Class derived from DimRpc
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29 | //
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30 | class EvidenceConfig: public DimRpc, public EvidenceServer {
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31 |
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32 | private:
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33 | FILE *File;
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34 | char *Buffer;
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35 | unsigned int BufferLength;
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36 | DimService *ConfigModified;
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37 | int ModifyTime;
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38 |
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39 | void rpcHandler();
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40 |
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41 | public:
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42 | EvidenceConfig(const char *);
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43 | ~EvidenceConfig();
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44 |
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45 | void ConfigChanged();
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46 | };
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47 |
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48 | // Constructor
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49 | EvidenceConfig::EvidenceConfig(const char *Filename):
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50 | DimRpc("ConfigRequest", "C", "C"), EvidenceServer(SERVER_NAME) {
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51 |
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52 | // Open configuration file
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53 | if ((File = fopen(Filename, "r")) == NULL) {
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54 | State(FATAL, "Could not open configuration file '%s' (%s)\n", Filename, strerror(errno));
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55 | }
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56 |
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57 | // Create DIM service to indicate changes of configuration file
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58 | struct stat Stat;
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59 | if (stat(Filename, &Stat) == -1) {
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60 | State(WARN, "Could not read last modification time of configuration file '%s' (%s)", Filename, strerror(errno));
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61 | ModifyTime = 0;
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62 | }
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63 | else ModifyTime = Stat.st_mtime;
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64 | ConfigModified = new DimService (SERVER_NAME"/ModifyTime", ModifyTime);
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65 |
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66 | // Disable buffering, so file modifications are immediately seen
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67 | if (setvbuf(File, NULL, _IONBF, 0) != 0) {
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68 | State(WARN, "Error setting configuration file '%s' to unbuffered mode", Filename);
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69 | }
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70 |
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71 | Buffer = NULL; // Will be allocated in rpcHandler()
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72 | BufferLength = 0;
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73 | }
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74 |
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75 | // Destructor
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76 | EvidenceConfig::~EvidenceConfig() {
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77 |
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78 | if (File != NULL) fclose(File);
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79 | delete[] Buffer;
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80 | }
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81 |
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82 | // Implementation of response to configuration request
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83 | void EvidenceConfig::rpcHandler() {
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84 |
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85 | char *Token1,*Token2,*Token3, *Request = getString();
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86 | struct stat FileStatus;
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87 |
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88 | // Check if Buffer[] is large enough to hold full file, enlarge if necessary
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89 | if (fstat(fileno(File), &FileStatus) == -1) {
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90 | State(FATAL, "Could not determine size of configuration file to allocate buffer (%s)", strerror(errno));
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91 | }
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92 | else if(BufferLength < FileStatus.st_size) {
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93 | delete[] Buffer;
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94 | Buffer = new char [FileStatus.st_size];
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95 | BufferLength = FileStatus.st_size;
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96 | }
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97 |
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98 | // Search for configuration item
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99 | rewind(File);
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100 | while (fgets(Buffer, BufferLength, File) != NULL) {
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101 |
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102 | // Combine lines that end with '+'
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103 | while (Buffer[strlen(Buffer)-2] == '+') {
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104 | if (fgets(Buffer+strlen(Buffer)-2, BufferLength-(strlen(Buffer)-2), File) == NULL) break;
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105 | }
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106 |
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107 | // Ignore comments
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108 | for (int i=0; i<strlen(Buffer); i++) if (Buffer[i] == '#') Buffer[i] = '\0';
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109 |
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110 | // Extract tokens
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111 | Token1 = strtok(Buffer, " \t:");
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112 | Token2 = strtok(NULL, " \t:");
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113 | Token3 = strtok(NULL, "\n");
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114 |
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115 | // Check if all tokens existing
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116 | if(Token1==NULL || Token2==NULL || Token3==NULL) continue;
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117 |
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118 | // Check for match and then send data (removing trainlin whitespace)
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119 | if (strstr(Request, Token1)!=NULL && strstr(Request, Token2)!=NULL) {
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120 | while (isspace(*Token3) != 0) Token3++;
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121 | setData(Token3);
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122 | break;
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123 | }
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124 | }
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125 |
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126 | // If configuration data not found, send empty string
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127 | if (feof(File)!=0) setData((char *) "");
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128 |
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129 | State(INFO, "Client '%s' (ID %d) requested '%s'. Send '%s'.",
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130 | DimServer::getClientName(),
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131 | DimServer::getClientId(),
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132 | Request, feof(File)!=0 ? "n/a" : Token3);
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133 | }
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134 |
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135 | // Signalisation of configuration change
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136 | void EvidenceConfig::ConfigChanged() {
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137 |
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138 | ModifyTime = time(NULL);
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139 | ConfigModified->updateService();
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140 | }
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141 |
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142 | //
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143 | // Declaring class static ensures destructor is called when exit() is invoked
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144 | //
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145 | int main(int argc, char *argv[]) {
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146 |
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147 | static EvidenceConfig Config(argc<2 ? DEFAULT_CONFIG : argv[1]);
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148 |
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149 | int Notify;
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150 | struct inotify_event Event;
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151 |
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152 | if ((Notify = inotify_init()) == -1) {
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153 | Config.State(EvidenceConfig::WARN, "inotify_init() failed, cannot monitor changes of configuration file (%s)\n", strerror(errno));
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154 | }
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155 | else if (inotify_add_watch(Notify, argc<2 ? DEFAULT_CONFIG : argv[1], IN_MODIFY) == -1) {
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156 | Config.State(EvidenceConfig::WARN, "Could not set inotify watch on configuration file (%s)\n", strerror(errno));
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157 | close(Notify);
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158 | Notify = -1;
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159 | }
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160 |
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161 | // Sleep until file changes or signal caught
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162 | while (!EvidenceServer::ExitRequest) {
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163 | if (Notify != -1) {
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164 | read(Notify, &Event, sizeof(Event));
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165 | Config.ConfigChanged();
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166 | }
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167 | else pause();
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168 | }
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169 |
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170 | if (Notify != -1) close(Notify);
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171 | }
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