1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.haxx.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22 /* <DESC>
23 * Set your system time from a remote HTTP server's Date: header.
24 * </DESC>
25 */
26 /* This example code only builds as-is on Windows.
27 *
28 * While Unix/Linux user, you do not need this software.
29 * You can achieve the same result as synctime using curl, awk and date.
30 * Set proxy as according to your network, but beware of proxy Cache-Control.
31 *
32 * To set your system clock, root access is required.
33 * # date -s "`curl -sI https://nist.time.gov/timezone.cgi?UTC/s/0 \
34 * | awk -F': ' '/Date: / {print $2}'`"
35 *
36 * To view remote webserver date and time.
37 * $ curl -sI https://nist.time.gov/timezone.cgi?UTC/s/0 \
38 * | awk -F': ' '/Date: / {print $2}'
39 *
40 * Synchronising your computer clock via Internet time server usually relies
41 * on DAYTIME, TIME, or NTP protocols. These protocols provide good accurate
42 * time synchronisation but it does not work very well through a
43 * firewall/proxy. Some adjustment has to be made to the firewall/proxy for
44 * these protocols to work properly.
45 *
46 * There is an indirect method. Since most webserver provide server time in
47 * their HTTP header, therefore you could synchronise your computer clock
48 * using HTTP protocol which has no problem with firewall/proxy.
49 *
50 * For this software to work, you should take note of these items.
51 * 1. Your firewall/proxy must allow your computer to surf internet.
52 * 2. Webserver system time must in sync with the NTP time server,
53 * or at least provide an accurate time keeping.
54 * 3. Webserver HTTP header does not provide the milliseconds units,
55 * so there is no way to get very accurate time.
56 * 4. This software could only provide an accuracy of +- a few seconds,
57 * as Round-Trip delay time is not taken into consideration.
58 * Compensation of network, firewall/proxy delay cannot be simply divide
59 * the Round-Trip delay time by half.
60 * 5. Win32 SetSystemTime() API will set your computer clock according to
61 * GMT/UTC time. Therefore your computer timezone must be properly set.
62 * 6. Webserver data should not be cached by the proxy server. Some
63 * webserver provide Cache-Control to prevent caching.
64 *
65 * References:
66 * https://web.archive.org/web/20100228012139/ \
67 * tf.nist.gov/timefreq/service/its.htm
68 * https://web.archive.org/web/20100409024302/ \
69 * tf.nist.gov/timefreq/service/firewall.htm
70 *
71 * Usage:
72 * This software will synchronise your computer clock only when you issue
73 * it with --synctime. By default, it only display the webserver's clock.
74 *
75 * Written by: Frank (contributed to libcurl)
76 *
77 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
78 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
79 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
80 *
81 * IN NO EVENT SHALL THE AUTHOR OF THIS SOFTWARE BE LIABLE FOR
82 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
83 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
84 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
85 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
86 * OF THIS SOFTWARE.
87 *
88 */
89
90 #include <stdio.h>
91 #include <time.h>
92 #ifndef __CYGWIN__
93 #include <winsock2.h>
94 #include <windows.h>
95 #endif
96 #include <curl/curl.h>
97
98
99 #define MAX_STRING 256
100 #define MAX_STRING1 MAX_STRING + 1
101
102 #define SYNCTIME_UA "synctime/1.0"
103
104 typedef struct
105 {
106 char http_proxy[MAX_STRING1];
107 char proxy_user[MAX_STRING1];
108 char timeserver[MAX_STRING1];
109 } conf_t;
110
111 const char DefaultTimeServer[3][MAX_STRING1] =
112 {
113 "https://nist.time.gov/",
114 "https://www.google.com/"
115 };
116
117 const char *DayStr[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
118 const char *MthStr[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
119 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
120
121 int ShowAllHeader;
122 int AutoSyncTime;
123 SYSTEMTIME SYSTime;
124 SYSTEMTIME LOCALTime;
125
126 #define HTTP_COMMAND_HEAD 0
127 #define HTTP_COMMAND_GET 1
128
129
SyncTime_CURL_WriteOutput(void * ptr,size_t size,size_t nmemb,void * stream)130 size_t SyncTime_CURL_WriteOutput(void *ptr, size_t size, size_t nmemb,
131 void *stream)
132 {
133 fwrite(ptr, size, nmemb, stream);
134 return (nmemb*size);
135 }
136
SyncTime_CURL_WriteHeader(void * ptr,size_t size,size_t nmemb,void * stream)137 size_t SyncTime_CURL_WriteHeader(void *ptr, size_t size, size_t nmemb,
138 void *stream)
139 {
140 char TmpStr1[26], TmpStr2[26];
141
142 (void)stream;
143
144 if(ShowAllHeader == 1)
145 fprintf(stderr, "%s", (char *)(ptr));
146
147 if(strncmp((char *)(ptr), "Date:", 5) == 0) {
148 if(ShowAllHeader == 0)
149 fprintf(stderr, "HTTP Server. %s", (char *)(ptr));
150
151 if(AutoSyncTime == 1) {
152 *TmpStr1 = 0;
153 *TmpStr2 = 0;
154 if(strlen((char *)(ptr)) > 50) /* Can prevent buffer overflow to
155 TmpStr1 & 2? */
156 AutoSyncTime = 0;
157 else {
158 int RetVal = sscanf((char *)(ptr), "Date: %s %hu %s %hu %hu:%hu:%hu",
159 TmpStr1, &SYSTime.wDay, TmpStr2, &SYSTime.wYear,
160 &SYSTime.wHour, &SYSTime.wMinute,
161 &SYSTime.wSecond);
162
163 if(RetVal == 7) {
164 int i;
165 SYSTime.wMilliseconds = 500; /* adjust to midpoint, 0.5 sec */
166 for(i = 0; i<12; i++) {
167 if(strcmp(MthStr[i], TmpStr2) == 0) {
168 SYSTime.wMonth = i + 1;
169 break;
170 }
171 }
172 AutoSyncTime = 3; /* Computer clock will be adjusted */
173 }
174 else {
175 AutoSyncTime = 0; /* Error in sscanf() fields conversion */
176 }
177 }
178 }
179 }
180
181 if(strncmp((char *)(ptr), "X-Cache: HIT", 12) == 0) {
182 fprintf(stderr, "ERROR: HTTP Server data is cached."
183 " Server Date is no longer valid.\n");
184 AutoSyncTime = 0;
185 }
186 return (nmemb*size);
187 }
188
SyncTime_CURL_Init(CURL * curl,char * proxy_port,char * proxy_user_password)189 void SyncTime_CURL_Init(CURL *curl, char *proxy_port,
190 char *proxy_user_password)
191 {
192 if(strlen(proxy_port) > 0)
193 curl_easy_setopt(curl, CURLOPT_PROXY, proxy_port);
194
195 if(strlen(proxy_user_password) > 0)
196 curl_easy_setopt(curl, CURLOPT_PROXYUSERPWD, proxy_user_password);
197
198 #ifdef SYNCTIME_UA
199 curl_easy_setopt(curl, CURLOPT_USERAGENT, SYNCTIME_UA);
200 #endif
201 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, *SyncTime_CURL_WriteOutput);
202 curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, *SyncTime_CURL_WriteHeader);
203 }
204
SyncTime_CURL_Fetch(CURL * curl,char * URL_Str,char * OutFileName,int HttpGetBody)205 int SyncTime_CURL_Fetch(CURL *curl, char *URL_Str, char *OutFileName,
206 int HttpGetBody)
207 {
208 FILE *outfile;
209 CURLcode res;
210
211 outfile = NULL;
212 if(HttpGetBody == HTTP_COMMAND_HEAD)
213 curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
214 else {
215 outfile = fopen(OutFileName, "wb");
216 curl_easy_setopt(curl, CURLOPT_WRITEDATA, outfile);
217 }
218
219 curl_easy_setopt(curl, CURLOPT_URL, URL_Str);
220 res = curl_easy_perform(curl);
221 if(outfile != NULL)
222 fclose(outfile);
223 return res; /* (CURLE_OK) */
224 }
225
showUsage(void)226 void showUsage(void)
227 {
228 fprintf(stderr, "SYNCTIME: Synchronising computer clock with time server"
229 " using HTTP protocol.\n");
230 fprintf(stderr, "Usage : SYNCTIME [Option]\n");
231 fprintf(stderr, "Options :\n");
232 fprintf(stderr, " --server=WEBSERVER Use this time server instead"
233 " of default.\n");
234 fprintf(stderr, " --showall Show all HTTP header.\n");
235 fprintf(stderr, " --synctime Synchronising computer clock"
236 " with time server.\n");
237 fprintf(stderr, " --proxy-user=USER[:PASS] Set proxy username and"
238 " password.\n");
239 fprintf(stderr, " --proxy=HOST[:PORT] Use HTTP proxy on given"
240 " port.\n");
241 fprintf(stderr, " --help Print this help.\n");
242 fprintf(stderr, "\n");
243 return;
244 }
245
conf_init(conf_t * conf)246 int conf_init(conf_t *conf)
247 {
248 int i;
249
250 *conf->http_proxy = 0;
251 for(i = 0; i<MAX_STRING1; i++)
252 conf->proxy_user[i] = 0; /* Clean up password from memory */
253 *conf->timeserver = 0;
254 return 1;
255 }
256
main(int argc,char * argv[])257 int main(int argc, char *argv[])
258 {
259 CURL *curl;
260 conf_t conf[1];
261 int RetValue;
262
263 ShowAllHeader = 0; /* Do not show HTTP Header */
264 AutoSyncTime = 0; /* Do not synchronise computer clock */
265 RetValue = 0; /* Successful Exit */
266 conf_init(conf);
267
268 if(argc > 1) {
269 int OptionIndex = 0;
270 while(OptionIndex < argc) {
271 if(strncmp(argv[OptionIndex], "--server=", 9) == 0)
272 snprintf(conf->timeserver, MAX_STRING, "%s", &argv[OptionIndex][9]);
273
274 if(strcmp(argv[OptionIndex], "--showall") == 0)
275 ShowAllHeader = 1;
276
277 if(strcmp(argv[OptionIndex], "--synctime") == 0)
278 AutoSyncTime = 1;
279
280 if(strncmp(argv[OptionIndex], "--proxy-user=", 13) == 0)
281 snprintf(conf->proxy_user, MAX_STRING, "%s", &argv[OptionIndex][13]);
282
283 if(strncmp(argv[OptionIndex], "--proxy=", 8) == 0)
284 snprintf(conf->http_proxy, MAX_STRING, "%s", &argv[OptionIndex][8]);
285
286 if((strcmp(argv[OptionIndex], "--help") == 0) ||
287 (strcmp(argv[OptionIndex], "/?") == 0)) {
288 showUsage();
289 return 0;
290 }
291 OptionIndex++;
292 }
293 }
294
295 if(*conf->timeserver == 0) /* Use default server for time information */
296 snprintf(conf->timeserver, MAX_STRING, "%s", DefaultTimeServer[0]);
297
298 /* Init CURL before usage */
299 curl_global_init(CURL_GLOBAL_ALL);
300 curl = curl_easy_init();
301 if(curl) {
302 struct tm *lt;
303 struct tm *gmt;
304 time_t tt;
305 time_t tt_local;
306 time_t tt_gmt;
307 double tzonediffFloat;
308 int tzonediffWord;
309 char timeBuf[61];
310 char tzoneBuf[16];
311
312 SyncTime_CURL_Init(curl, conf->http_proxy, conf->proxy_user);
313
314 /* Calculating time diff between GMT and localtime */
315 tt = time(0);
316 lt = localtime(&tt);
317 tt_local = mktime(lt);
318 gmt = gmtime(&tt);
319 tt_gmt = mktime(gmt);
320 tzonediffFloat = difftime(tt_local, tt_gmt);
321 tzonediffWord = (int)(tzonediffFloat/3600.0);
322
323 if((double)(tzonediffWord * 3600) == tzonediffFloat)
324 snprintf(tzoneBuf, 15, "%+03d'00'", tzonediffWord);
325 else
326 snprintf(tzoneBuf, 15, "%+03d'30'", tzonediffWord);
327
328 /* Get current system time and local time */
329 GetSystemTime(&SYSTime);
330 GetLocalTime(&LOCALTime);
331 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
332 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
333 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
334 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
335 LOCALTime.wMilliseconds);
336
337 fprintf(stderr, "Fetch: %s\n\n", conf->timeserver);
338 fprintf(stderr, "Before HTTP. Date: %s%s\n\n", timeBuf, tzoneBuf);
339
340 /* HTTP HEAD command to the Webserver */
341 SyncTime_CURL_Fetch(curl, conf->timeserver, "index.htm",
342 HTTP_COMMAND_HEAD);
343
344 GetLocalTime(&LOCALTime);
345 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
346 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
347 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
348 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
349 LOCALTime.wMilliseconds);
350 fprintf(stderr, "\nAfter HTTP. Date: %s%s\n", timeBuf, tzoneBuf);
351
352 if(AutoSyncTime == 3) {
353 /* Synchronising computer clock */
354 if(!SetSystemTime(&SYSTime)) { /* Set system time */
355 fprintf(stderr, "ERROR: Unable to set system time.\n");
356 RetValue = 1;
357 }
358 else {
359 /* Successfully re-adjusted computer clock */
360 GetLocalTime(&LOCALTime);
361 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
362 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
363 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
364 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
365 LOCALTime.wMilliseconds);
366 fprintf(stderr, "\nNew System's Date: %s%s\n", timeBuf, tzoneBuf);
367 }
368 }
369
370 /* Cleanup before exit */
371 conf_init(conf);
372 curl_easy_cleanup(curl);
373 }
374 return RetValue;
375 }
376