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Rev | Author | Line No. | Line |
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1140 | dev | 1 | /****************************************************************** |
2 | * |
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1143 | dev | 3 | * Daemon which waits on specified TCP port for special string |
4 | * and reboots the computer. |
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1140 | dev | 5 | * |
6 | * Command line: rebootdaemon [--port PORT] [--config CONFIG_FILE] |
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7 | * Defaults are port 19 and config /etc/rebootdaemon.conf. |
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8 | * |
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9 | * Config file looks like: |
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10 | * -------------------------- |
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11 | * port=19 |
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12 | * password="some password" |
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13 | * -------------------------- |
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14 | * |
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15 | * Usage example (from any other host): |
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16 | * echo -n "some password" | nc host_to_rebot 19 |
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17 | * |
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18 | * Copyleft 2005 Anatoli Klassen |
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19 | * |
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20 | ******************************************************************/ |
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21 | |||
22 | #include <stdlib.h> |
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23 | #include <stdio.h> |
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24 | #include <string.h> |
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25 | #include <stdarg.h> |
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26 | #include <errno.h> |
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27 | #include <signal.h> |
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28 | #include <unistd.h> |
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29 | #include <netdb.h> |
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30 | #include <syslog.h> |
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31 | #include <sys/types.h> |
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32 | #include <sys/socket.h> |
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33 | #include <sys/wait.h> |
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34 | #include <sys/reboot.h> |
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35 | #include <netinet/in.h> |
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36 | #include <arpa/inet.h> |
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37 | |||
1143 | dev | 38 | #define DEFAULT_PORT 19 |
39 | #define DEFAULT_CFG_FILE "/etc/rebootdaemon.conf" |
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1140 | dev | 40 | #define CMDSIZE 4096 |
41 | #define BUFSIZE 4096 |
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42 | #define MAX_CONFIG_LINE 4096 |
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43 | #define PORT_MIN 1 |
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44 | #define PORT_MAX 65535 |
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45 | |||
46 | #define PARAM_PORT_1 "-p" |
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47 | #define PARAM_PORT_2 "--port" |
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48 | #define PARAM_CONFIG_1 "-c" |
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49 | #define PARAM_CONFIG_2 "--config" |
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50 | #define CONFIG_PORT "port" |
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51 | #define CONFIG_PASSWORD "password" |
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52 | |||
53 | struct config { |
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54 | int port; |
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55 | char password[MAX_CONFIG_LINE]; |
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56 | }; |
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57 | |||
58 | static int parse_cmd_line(int argc, char* argv[], long *port, char *config_name); |
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59 | static int parse_config_file(char *config_name, long *port, char *password); |
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60 | |||
61 | static int min(int a, int b) |
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62 | { |
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63 | return (a < b) ? a : b; |
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64 | } |
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65 | |||
66 | static int establish(unsigned short portnum) |
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67 | { |
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68 | int s; |
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69 | struct sockaddr_in sa; |
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70 | |||
71 | memset(&sa, 0, sizeof(struct sockaddr_in)); |
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72 | |||
73 | sa.sin_family = AF_INET; |
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74 | sa.sin_port = htons(portnum); |
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75 | sa.sin_addr.s_addr = INADDR_ANY; |
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76 | |||
77 | if((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) |
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78 | return -1; |
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79 | |||
80 | if(bind(s, (struct sockaddr *)&sa, sizeof(struct sockaddr_in)) < 0) { |
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81 | close(s); |
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82 | return -1; |
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83 | } |
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84 | |||
85 | listen(s, 1); |
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86 | |||
87 | return s; |
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88 | } |
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89 | |||
1143 | dev | 90 | static void listen_socket(struct config *cfg, int socket) |
1142 | dev | 91 | { |
92 | int t; |
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93 | char cmd[CMDSIZE]; |
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94 | char buf[BUFSIZE]; |
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95 | char* msg; |
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96 | int br; |
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97 | struct sockaddr_in sa; |
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98 | socklen_t sa_len; |
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99 | |||
100 | for(;;) { |
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101 | sa_len = sizeof(sa); |
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102 | if((t = accept(socket, (struct sockaddr *)&sa, &sa_len)) < 0) { |
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103 | if(errno == EINTR) /* EINTR might happen on accept(), */ |
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104 | continue; /* try again */ |
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105 | |||
106 | msg = strerror(errno); |
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107 | syslog(LOG_ERR, "cannot get connection, %s", msg); |
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108 | continue; |
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109 | } |
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110 | |||
111 | msg = inet_ntoa(sa.sin_addr); |
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112 | syslog(LOG_INFO, "connect from %s", msg); |
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113 | |||
114 | cmd[0] = '\0'; |
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115 | while((br = recv(t, buf, BUFSIZE, 0)) > 0) { |
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116 | strncat(cmd, buf, min(br, sizeof(cmd) - strlen(cmd) - 1)); |
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117 | } |
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118 | sleep(1); |
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119 | close(t); |
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120 | |||
121 | syslog(LOG_INFO, "got command [%s]", cmd); |
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122 | |||
1143 | dev | 123 | if(0 == strncmp(cmd, cfg->password, sizeof(cmd))) { |
1142 | dev | 124 | syslog(LOG_EMERG, "REBOOT"); |
125 | sleep(5); |
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126 | if(reboot(RB_AUTOBOOT) < 0) { |
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127 | msg = strerror(errno); |
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128 | syslog(LOG_ERR, "cannot reboot, %s", msg); |
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129 | } |
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130 | } |
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131 | } |
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132 | } |
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133 | |||
1140 | dev | 134 | static int print_cmd_error(char *msg, char *value) |
135 | { |
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136 | fprintf(stderr, "%s", msg); |
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137 | if(value) fprintf(stderr, " - %s\n", value); |
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138 | fprintf(stderr, "\n"); |
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139 | |||
140 | return 0; |
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141 | } |
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142 | |||
143 | static int print_config_error(char *config_name, int line, char *msg, char *value) |
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144 | { |
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145 | fprintf(stderr, "Error in %s, line %d: %s", config_name, line, msg); |
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146 | if(value) fprintf(stderr, " - %s", value); |
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147 | fprintf(stderr, "\n"); |
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148 | |||
149 | return 0; |
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150 | } |
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151 | |||
1143 | dev | 152 | static int read_config(struct config *cfg, int argc, char* argv[]) |
1140 | dev | 153 | { |
154 | long cmd_port; |
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155 | long file_port; |
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156 | char cmd_config[MAX_CONFIG_LINE]; |
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157 | |||
1143 | dev | 158 | if(!parse_cmd_line(argc, argv, &cmd_port, cmd_config)) |
159 | return 0; |
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1140 | dev | 160 | |
1143 | dev | 161 | if(!parse_config_file(cmd_config[0] != '\0' ? cmd_config : DEFAULT_CFG_FILE, &file_port, cfg->password)) |
162 | return 0; |
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1140 | dev | 163 | |
1143 | dev | 164 | if(cfg->password[0] == '\0') { |
1140 | dev | 165 | fprintf(stderr, "Password is not set\n"); |
166 | return 0; |
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167 | } |
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168 | |||
169 | if(cmd_port > 0) |
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1143 | dev | 170 | cfg->port = (int)cmd_port; |
1140 | dev | 171 | else if(file_port > 0) |
1143 | dev | 172 | cfg->port = (int)file_port; |
1140 | dev | 173 | else |
1143 | dev | 174 | cfg->port = DEFAULT_PORT; |
1140 | dev | 175 | |
176 | return 1; |
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177 | } |
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178 | |||
179 | static int parse_cmd_line(int argc, char* argv[], long *port, char *config_name) |
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180 | { |
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181 | char *end; |
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182 | int i; |
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183 | |||
184 | *port = 0; |
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185 | config_name[0] = '\0'; |
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186 | |||
187 | for(i = 1; i < argc; i++) { |
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188 | if(0 == strcmp(argv[i], PARAM_PORT_1) || 0 == strcmp(argv[i], PARAM_PORT_2)) { |
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189 | if(*port > 0) |
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190 | return print_cmd_error("Port is already set", NULL); |
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191 | |||
192 | if(++i < argc) { |
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193 | *port = strtol(argv[i], &end, 10); |
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194 | if(*end != '\0' || *port < PORT_MIN || *port > PORT_MAX) |
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195 | return print_cmd_error("Port number must be integer between 1 and 65535", NULL); |
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196 | } |
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197 | else { |
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198 | return print_cmd_error("Port number expected", NULL); |
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199 | } |
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200 | } |
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201 | else if(0 == strcmp(argv[i], PARAM_CONFIG_1) || 0 == strcmp(argv[i], PARAM_CONFIG_2)) { |
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202 | if(config_name[0] != '\0') |
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203 | return print_cmd_error("Config file is already set", NULL); |
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204 | |||
205 | if(++i < argc) { |
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206 | strncpy(config_name, argv[i], MAX_CONFIG_LINE); |
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207 | if(config_name[MAX_CONFIG_LINE - 1] != '\0') |
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208 | return print_cmd_error("Config file name is too long", NULL); |
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209 | } |
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210 | else { |
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211 | return print_cmd_error("Config file expected", NULL); |
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212 | } |
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213 | } |
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214 | else { |
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215 | return print_cmd_error("Unknown parameter", argv[i]); |
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216 | } |
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217 | } |
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218 | |||
219 | return 1; |
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220 | } |
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221 | |||
222 | |||
223 | static int parse_config_file(char *config_name, long *port, char *password) |
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224 | { |
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225 | FILE *config_file; |
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226 | char buf[MAX_CONFIG_LINE]; |
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227 | char *line; |
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228 | char *subline; |
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229 | char *cur; |
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230 | int count; |
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231 | |||
232 | config_file = fopen(config_name, "r"); |
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233 | if(!config_file) { |
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234 | fprintf(stderr, "Can not open config file %s: %s\n", config_name, strerror(errno)); |
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235 | return 0; |
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236 | } |
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237 | |||
238 | count = 0; |
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239 | while(fgets(buf, sizeof(buf), config_file)) { |
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240 | count++; |
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241 | line = buf; |
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242 | |||
243 | /* skip end spaces */ |
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244 | int len = strlen(line); |
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245 | while(len && isspace(line[len-1])) --len; |
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246 | if(!len) continue; |
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247 | line[len] = '\0'; |
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248 | |||
249 | /* skip begin spaces */ |
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250 | while(line[0] != '\0' && isspace(line[0])) line++; |
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251 | |||
252 | if('#' == line[0]) { /* skip comment lines */ |
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253 | continue; |
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254 | } |
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255 | else if(strncmp(line, CONFIG_PORT, min(sizeof(CONFIG_PORT) - 1, len)) == 0) { |
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256 | subline = line + sizeof(CONFIG_PORT) - 1; |
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257 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
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258 | if('=' != subline[0]) |
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259 | return print_config_error(config_name, count, "Equal sign expected", NULL); |
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260 | subline++; |
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261 | *port = strtol(subline, &subline, 10); |
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262 | if(*port < PORT_MIN || *port > PORT_MAX) |
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263 | return print_config_error(config_name, count, |
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264 | "Port number must be integer between 1 and 65535", NULL); |
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265 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
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266 | if('\0' != subline[0] && '#' != subline[0]) |
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267 | return print_config_error(config_name, count, "End of line expected", NULL); |
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268 | } |
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269 | else if(strncmp(line, CONFIG_PASSWORD, min(sizeof(CONFIG_PASSWORD) - 1, len)) == 0) { |
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270 | subline = line + sizeof(CONFIG_PASSWORD) - 1; |
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271 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
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272 | if('=' != subline[0]) |
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273 | return print_config_error(config_name, count, "Equal sign expected", NULL); |
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274 | subline++; |
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275 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
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276 | if('"' != subline[0]) |
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277 | return print_config_error(config_name, count, "Open quot expected", NULL); |
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278 | subline++; |
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279 | |||
280 | cur = password; |
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281 | while(subline[0] != '\0' && subline[0] != '"') { |
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282 | cur[0] = subline[0]; |
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283 | cur++; |
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284 | subline++; |
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285 | } |
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286 | |||
287 | cur[0] = '\0'; |
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288 | if('"' != subline[0]) |
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289 | return print_config_error(config_name, count, "Close quot expected", NULL); |
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290 | subline++; |
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291 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
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292 | if('\0' != subline[0] && '#' != subline[0]) |
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293 | return print_config_error(config_name, count, "End of line expected", NULL); |
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294 | } |
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295 | else { |
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296 | return print_config_error(config_name, count, "Unknown config parameter", line); |
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297 | } |
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298 | } |
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299 | |||
300 | if(fclose(config_file) != 0) { |
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301 | fprintf(stderr, "Can not close config file %s: %s\n", config_name, strerror(errno)); |
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302 | return 0; |
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303 | } |
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304 | |||
305 | return 1; |
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306 | } |
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307 | |||
1143 | dev | 308 | static int create_child(int socket) |
309 | { |
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310 | pid_t child; |
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311 | |||
312 | child = fork(); |
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313 | if(child == -1) { |
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314 | fprintf(stderr, "Cannot fork: %s\n", strerror(errno)); |
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315 | return 2; /* an unexpected error */ |
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316 | } |
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317 | else if(child > 0) { |
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318 | if(close(socket) != 0) { |
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319 | fprintf(stderr, "Cannot close socket: %s\n", strerror(errno)); |
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320 | return 2; /* an unexpected error */ |
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321 | } |
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322 | return 0; /* we are the parent */ |
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323 | } |
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324 | else { |
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325 | return 1; /* we are the child */ |
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326 | } |
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327 | } |
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328 | |||
329 | static int close_descr(int d) |
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330 | { |
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331 | if(close(d) != 0) { |
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332 | syslog(LOG_ERR, "Cannot close descriptor %d: %s\n", d, strerror(errno)); |
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333 | return 0; |
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334 | } |
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335 | return 1; |
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336 | } |
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337 | |||
1140 | dev | 338 | int main(int argc, char* argv[]) |
339 | { |
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1143 | dev | 340 | int socket; |
341 | struct config cfg; |
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1140 | dev | 342 | |
343 | |||
1143 | dev | 344 | /* get config */ |
345 | if(!read_config(&cfg, argc, argv)) return 1; |
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346 | |||
347 | /* try to listen the port */ |
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348 | if((socket = establish(cfg.port)) < 0) { |
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1140 | dev | 349 | fprintf(stderr, "Cannot listen to port %i\n", cfg.port); |
350 | return 1; |
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351 | } |
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352 | |||
1143 | dev | 353 | /* fork and release the console */ |
354 | switch(create_child(socket)) { |
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355 | case 0: return 0; |
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356 | case 2: return 2; |
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357 | } |
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1140 | dev | 358 | |
1143 | dev | 359 | /* continue as first child */ |
360 | if(setsid() == -1) { |
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361 | fprintf(stderr, "Cannot create session: %s\n", strerror(errno)); |
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362 | return 2; |
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363 | } |
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364 | |||
365 | /* fork the second time */ |
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366 | switch(create_child(socket)) { |
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367 | case 0: return 0; |
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368 | case 2: return 2; |
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369 | } |
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370 | |||
371 | /* continue as final child, from now do not use console for error output */ |
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372 | chdir("/"); |
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373 | umask(0); |
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374 | if(!close_descr(0)) return 2; |
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375 | if(!close_descr(1)) return 2; |
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376 | if(!close_descr(2)) return 2; |
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377 | |||
378 | syslog(LOG_INFO, "listen on %d", cfg.port); |
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379 | listen_socket(&cfg, socket); |
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380 | |||
1140 | dev | 381 | return 0; |
382 | } |
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383 |