Rev 1142 | Rev 1144 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
1140 | dev | 1 | /****************************************************************** |
2 | * |
||
1143 | dev | 3 | * Daemon which waits on specified TCP port for special string |
4 | * and reboots the computer. |
||
1140 | dev | 5 | * |
6 | * Command line: rebootdaemon [--port PORT] [--config CONFIG_FILE] |
||
7 | * Defaults are port 19 and config /etc/rebootdaemon.conf. |
||
8 | * |
||
9 | * Config file looks like: |
||
10 | * -------------------------- |
||
11 | * port=19 |
||
12 | * password="some password" |
||
13 | * -------------------------- |
||
14 | * |
||
15 | * Usage example (from any other host): |
||
16 | * echo -n "some password" | nc host_to_rebot 19 |
||
17 | * |
||
18 | * Copyleft 2005 Anatoli Klassen |
||
19 | * |
||
20 | ******************************************************************/ |
||
21 | |||
22 | #include <stdlib.h> |
||
23 | #include <stdio.h> |
||
24 | #include <string.h> |
||
25 | #include <stdarg.h> |
||
26 | #include <errno.h> |
||
27 | #include <signal.h> |
||
28 | #include <unistd.h> |
||
29 | #include <netdb.h> |
||
30 | #include <syslog.h> |
||
31 | #include <sys/types.h> |
||
32 | #include <sys/socket.h> |
||
33 | #include <sys/wait.h> |
||
34 | #include <sys/reboot.h> |
||
35 | #include <netinet/in.h> |
||
36 | #include <arpa/inet.h> |
||
37 | |||
1143 | dev | 38 | #define DEFAULT_PORT 19 |
39 | #define DEFAULT_CFG_FILE "/etc/rebootdaemon.conf" |
||
1140 | dev | 40 | #define CMDSIZE 4096 |
41 | #define BUFSIZE 4096 |
||
42 | #define MAX_CONFIG_LINE 4096 |
||
43 | #define PORT_MIN 1 |
||
44 | #define PORT_MAX 65535 |
||
45 | |||
46 | #define PARAM_PORT_1 "-p" |
||
47 | #define PARAM_PORT_2 "--port" |
||
48 | #define PARAM_CONFIG_1 "-c" |
||
49 | #define PARAM_CONFIG_2 "--config" |
||
50 | #define CONFIG_PORT "port" |
||
51 | #define CONFIG_PASSWORD "password" |
||
52 | |||
53 | struct config { |
||
54 | int port; |
||
55 | char password[MAX_CONFIG_LINE]; |
||
56 | }; |
||
57 | |||
58 | static int parse_cmd_line(int argc, char* argv[], long *port, char *config_name); |
||
59 | static int parse_config_file(char *config_name, long *port, char *password); |
||
60 | |||
61 | static int min(int a, int b) |
||
62 | { |
||
63 | return (a < b) ? a : b; |
||
64 | } |
||
65 | |||
66 | static int establish(unsigned short portnum) |
||
67 | { |
||
68 | int s; |
||
69 | struct sockaddr_in sa; |
||
70 | |||
71 | memset(&sa, 0, sizeof(struct sockaddr_in)); |
||
72 | |||
73 | sa.sin_family = AF_INET; |
||
74 | sa.sin_port = htons(portnum); |
||
75 | sa.sin_addr.s_addr = INADDR_ANY; |
||
76 | |||
77 | if((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) |
||
78 | return -1; |
||
79 | |||
80 | if(bind(s, (struct sockaddr *)&sa, sizeof(struct sockaddr_in)) < 0) { |
||
81 | close(s); |
||
82 | return -1; |
||
83 | } |
||
84 | |||
85 | listen(s, 1); |
||
86 | |||
87 | return s; |
||
88 | } |
||
89 | |||
1143 | dev | 90 | static void listen_socket(struct config *cfg, int socket) |
1142 | dev | 91 | { |
92 | int t; |
||
93 | char cmd[CMDSIZE]; |
||
94 | char buf[BUFSIZE]; |
||
95 | char* msg; |
||
96 | int br; |
||
97 | struct sockaddr_in sa; |
||
98 | socklen_t sa_len; |
||
99 | |||
100 | for(;;) { |
||
101 | sa_len = sizeof(sa); |
||
102 | if((t = accept(socket, (struct sockaddr *)&sa, &sa_len)) < 0) { |
||
103 | if(errno == EINTR) /* EINTR might happen on accept(), */ |
||
104 | continue; /* try again */ |
||
105 | |||
106 | msg = strerror(errno); |
||
107 | syslog(LOG_ERR, "cannot get connection, %s", msg); |
||
108 | continue; |
||
109 | } |
||
110 | |||
111 | msg = inet_ntoa(sa.sin_addr); |
||
112 | syslog(LOG_INFO, "connect from %s", msg); |
||
113 | |||
114 | cmd[0] = '\0'; |
||
115 | while((br = recv(t, buf, BUFSIZE, 0)) > 0) { |
||
116 | strncat(cmd, buf, min(br, sizeof(cmd) - strlen(cmd) - 1)); |
||
117 | } |
||
118 | sleep(1); |
||
119 | close(t); |
||
120 | |||
121 | syslog(LOG_INFO, "got command [%s]", cmd); |
||
122 | |||
1143 | dev | 123 | if(0 == strncmp(cmd, cfg->password, sizeof(cmd))) { |
1142 | dev | 124 | syslog(LOG_EMERG, "REBOOT"); |
125 | sleep(5); |
||
126 | if(reboot(RB_AUTOBOOT) < 0) { |
||
127 | msg = strerror(errno); |
||
128 | syslog(LOG_ERR, "cannot reboot, %s", msg); |
||
129 | } |
||
130 | } |
||
131 | } |
||
132 | } |
||
133 | |||
1140 | dev | 134 | static int print_cmd_error(char *msg, char *value) |
135 | { |
||
136 | fprintf(stderr, "%s", msg); |
||
137 | if(value) fprintf(stderr, " - %s\n", value); |
||
138 | fprintf(stderr, "\n"); |
||
139 | |||
140 | return 0; |
||
141 | } |
||
142 | |||
143 | static int print_config_error(char *config_name, int line, char *msg, char *value) |
||
144 | { |
||
145 | fprintf(stderr, "Error in %s, line %d: %s", config_name, line, msg); |
||
146 | if(value) fprintf(stderr, " - %s", value); |
||
147 | fprintf(stderr, "\n"); |
||
148 | |||
149 | return 0; |
||
150 | } |
||
151 | |||
1143 | dev | 152 | static int read_config(struct config *cfg, int argc, char* argv[]) |
1140 | dev | 153 | { |
154 | long cmd_port; |
||
155 | long file_port; |
||
156 | char cmd_config[MAX_CONFIG_LINE]; |
||
157 | |||
1143 | dev | 158 | if(!parse_cmd_line(argc, argv, &cmd_port, cmd_config)) |
159 | return 0; |
||
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; |
||
1140 | dev | 163 | |
1143 | dev | 164 | if(cfg->password[0] == '\0') { |
1140 | dev | 165 | fprintf(stderr, "Password is not set\n"); |
166 | return 0; |
||
167 | } |
||
168 | |||
169 | if(cmd_port > 0) |
||
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; |
||
177 | } |
||
178 | |||
179 | static int parse_cmd_line(int argc, char* argv[], long *port, char *config_name) |
||
180 | { |
||
181 | char *end; |
||
182 | int i; |
||
183 | |||
184 | *port = 0; |
||
185 | config_name[0] = '\0'; |
||
186 | |||
187 | for(i = 1; i < argc; i++) { |
||
188 | if(0 == strcmp(argv[i], PARAM_PORT_1) || 0 == strcmp(argv[i], PARAM_PORT_2)) { |
||
189 | if(*port > 0) |
||
190 | return print_cmd_error("Port is already set", NULL); |
||
191 | |||
192 | if(++i < argc) { |
||
193 | *port = strtol(argv[i], &end, 10); |
||
194 | if(*end != '\0' || *port < PORT_MIN || *port > PORT_MAX) |
||
195 | return print_cmd_error("Port number must be integer between 1 and 65535", NULL); |
||
196 | } |
||
197 | else { |
||
198 | return print_cmd_error("Port number expected", NULL); |
||
199 | } |
||
200 | } |
||
201 | else if(0 == strcmp(argv[i], PARAM_CONFIG_1) || 0 == strcmp(argv[i], PARAM_CONFIG_2)) { |
||
202 | if(config_name[0] != '\0') |
||
203 | return print_cmd_error("Config file is already set", NULL); |
||
204 | |||
205 | if(++i < argc) { |
||
206 | strncpy(config_name, argv[i], MAX_CONFIG_LINE); |
||
207 | if(config_name[MAX_CONFIG_LINE - 1] != '\0') |
||
208 | return print_cmd_error("Config file name is too long", NULL); |
||
209 | } |
||
210 | else { |
||
211 | return print_cmd_error("Config file expected", NULL); |
||
212 | } |
||
213 | } |
||
214 | else { |
||
215 | return print_cmd_error("Unknown parameter", argv[i]); |
||
216 | } |
||
217 | } |
||
218 | |||
219 | return 1; |
||
220 | } |
||
221 | |||
222 | |||
223 | static int parse_config_file(char *config_name, long *port, char *password) |
||
224 | { |
||
225 | FILE *config_file; |
||
226 | char buf[MAX_CONFIG_LINE]; |
||
227 | char *line; |
||
228 | char *subline; |
||
229 | char *cur; |
||
230 | int count; |
||
231 | |||
232 | config_file = fopen(config_name, "r"); |
||
233 | if(!config_file) { |
||
234 | fprintf(stderr, "Can not open config file %s: %s\n", config_name, strerror(errno)); |
||
235 | return 0; |
||
236 | } |
||
237 | |||
238 | count = 0; |
||
239 | while(fgets(buf, sizeof(buf), config_file)) { |
||
240 | count++; |
||
241 | line = buf; |
||
242 | |||
243 | /* skip end spaces */ |
||
244 | int len = strlen(line); |
||
245 | while(len && isspace(line[len-1])) --len; |
||
246 | if(!len) continue; |
||
247 | line[len] = '\0'; |
||
248 | |||
249 | /* skip begin spaces */ |
||
250 | while(line[0] != '\0' && isspace(line[0])) line++; |
||
251 | |||
252 | if('#' == line[0]) { /* skip comment lines */ |
||
253 | continue; |
||
254 | } |
||
255 | else if(strncmp(line, CONFIG_PORT, min(sizeof(CONFIG_PORT) - 1, len)) == 0) { |
||
256 | subline = line + sizeof(CONFIG_PORT) - 1; |
||
257 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
||
258 | if('=' != subline[0]) |
||
259 | return print_config_error(config_name, count, "Equal sign expected", NULL); |
||
260 | subline++; |
||
261 | *port = strtol(subline, &subline, 10); |
||
262 | if(*port < PORT_MIN || *port > PORT_MAX) |
||
263 | return print_config_error(config_name, count, |
||
264 | "Port number must be integer between 1 and 65535", NULL); |
||
265 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
||
266 | if('\0' != subline[0] && '#' != subline[0]) |
||
267 | return print_config_error(config_name, count, "End of line expected", NULL); |
||
268 | } |
||
269 | else if(strncmp(line, CONFIG_PASSWORD, min(sizeof(CONFIG_PASSWORD) - 1, len)) == 0) { |
||
270 | subline = line + sizeof(CONFIG_PASSWORD) - 1; |
||
271 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
||
272 | if('=' != subline[0]) |
||
273 | return print_config_error(config_name, count, "Equal sign expected", NULL); |
||
274 | subline++; |
||
275 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
||
276 | if('"' != subline[0]) |
||
277 | return print_config_error(config_name, count, "Open quot expected", NULL); |
||
278 | subline++; |
||
279 | |||
280 | cur = password; |
||
281 | while(subline[0] != '\0' && subline[0] != '"') { |
||
282 | cur[0] = subline[0]; |
||
283 | cur++; |
||
284 | subline++; |
||
285 | } |
||
286 | |||
287 | cur[0] = '\0'; |
||
288 | if('"' != subline[0]) |
||
289 | return print_config_error(config_name, count, "Close quot expected", NULL); |
||
290 | subline++; |
||
291 | while(subline[0] != '\0' && isspace(subline[0])) subline++; |
||
292 | if('\0' != subline[0] && '#' != subline[0]) |
||
293 | return print_config_error(config_name, count, "End of line expected", NULL); |
||
294 | } |
||
295 | else { |
||
296 | return print_config_error(config_name, count, "Unknown config parameter", line); |
||
297 | } |
||
298 | } |
||
299 | |||
300 | if(fclose(config_file) != 0) { |
||
301 | fprintf(stderr, "Can not close config file %s: %s\n", config_name, strerror(errno)); |
||
302 | return 0; |
||
303 | } |
||
304 | |||
305 | return 1; |
||
306 | } |
||
307 | |||
1143 | dev | 308 | static int create_child(int socket) |
309 | { |
||
310 | pid_t child; |
||
311 | |||
312 | child = fork(); |
||
313 | if(child == -1) { |
||
314 | fprintf(stderr, "Cannot fork: %s\n", strerror(errno)); |
||
315 | return 2; /* an unexpected error */ |
||
316 | } |
||
317 | else if(child > 0) { |
||
318 | if(close(socket) != 0) { |
||
319 | fprintf(stderr, "Cannot close socket: %s\n", strerror(errno)); |
||
320 | return 2; /* an unexpected error */ |
||
321 | } |
||
322 | return 0; /* we are the parent */ |
||
323 | } |
||
324 | else { |
||
325 | return 1; /* we are the child */ |
||
326 | } |
||
327 | } |
||
328 | |||
329 | static int close_descr(int d) |
||
330 | { |
||
331 | if(close(d) != 0) { |
||
332 | syslog(LOG_ERR, "Cannot close descriptor %d: %s\n", d, strerror(errno)); |
||
333 | return 0; |
||
334 | } |
||
335 | return 1; |
||
336 | } |
||
337 | |||
1140 | dev | 338 | int main(int argc, char* argv[]) |
339 | { |
||
1143 | dev | 340 | int socket; |
341 | struct config cfg; |
||
1140 | dev | 342 | |
343 | |||
1143 | dev | 344 | /* get config */ |
345 | if(!read_config(&cfg, argc, argv)) return 1; |
||
346 | |||
347 | /* try to listen the port */ |
||
348 | if((socket = establish(cfg.port)) < 0) { |
||
1140 | dev | 349 | fprintf(stderr, "Cannot listen to port %i\n", cfg.port); |
350 | return 1; |
||
351 | } |
||
352 | |||
1143 | dev | 353 | /* fork and release the console */ |
354 | switch(create_child(socket)) { |
||
355 | case 0: return 0; |
||
356 | case 2: return 2; |
||
357 | } |
||
1140 | dev | 358 | |
1143 | dev | 359 | /* continue as first child */ |
360 | if(setsid() == -1) { |
||
361 | fprintf(stderr, "Cannot create session: %s\n", strerror(errno)); |
||
362 | return 2; |
||
363 | } |
||
364 | |||
365 | /* fork the second time */ |
||
366 | switch(create_child(socket)) { |
||
367 | case 0: return 0; |
||
368 | case 2: return 2; |
||
369 | } |
||
370 | |||
371 | /* continue as final child, from now do not use console for error output */ |
||
372 | chdir("/"); |
||
373 | umask(0); |
||
374 | if(!close_descr(0)) return 2; |
||
375 | if(!close_descr(1)) return 2; |
||
376 | if(!close_descr(2)) return 2; |
||
377 | |||
378 | syslog(LOG_INFO, "listen on %d", cfg.port); |
||
379 | listen_socket(&cfg, socket); |
||
380 | |||
1140 | dev | 381 | return 0; |
382 | } |
||
383 |