1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24 /* <DESC>
25 * Set your system time from a remote HTTP server's Date: header.
26 * </DESC>
27 */
28 /* This example code only builds as-is on Windows.
29 *
30 * While Unix/Linux user, you do not need this software.
31 * You can achieve the same result as synctime using curl, awk and date.
32 * Set proxy as according to your network, but beware of proxy Cache-Control.
33 *
34 * To set your system clock, root access is required.
35 * # date -s "`curl -sI https://nist.time.gov/timezone.cgi?UTC/s/0 \
36 * | awk -F': ' '/Date: / {print $2}'`"
37 *
38 * To view remote webserver date and time.
39 * $ curl -sI https://nist.time.gov/timezone.cgi?UTC/s/0 \
40 * | awk -F': ' '/Date: / {print $2}'
41 *
42 * Synchronising your computer clock via Internet time server usually relies
43 * on DAYTIME, TIME, or NTP protocols. These protocols provide good accurate
44 * time synchronization but it does not work well through a
45 * firewall/proxy. Some adjustment has to be made to the firewall/proxy for
46 * these protocols to work properly.
47 *
48 * There is an indirect method. Since most webserver provide server time in
49 * their HTTP header, therefore you could synchronise your computer clock
50 * using HTTP protocol which has no problem with firewall/proxy.
51 *
52 * For this software to work, you should take note of these items.
53 * 1. Your firewall/proxy must allow your computer to surf Internet.
54 * 2. Webserver system time must in sync with the NTP time server,
55 * or at least provide an accurate time keeping.
56 * 3. Webserver HTTP header does not provide the milliseconds units,
57 * so there is no way to get an accurate time.
58 * 4. This software could only provide an accuracy of +- a few seconds,
59 * as Round-Trip delay time is not taken into consideration.
60 * Compensation of network, firewall/proxy delay cannot be simply divide
61 * the Round-Trip delay time by half.
62 * 5. Win32 SetSystemTime() API sets your computer clock according to
63 * GMT/UTC time. Therefore your computer timezone must be properly set.
64 * 6. Webserver data should not be cached by the proxy server. Some
65 * webserver provide Cache-Control to prevent caching.
66 *
67 * References:
68 * https://web.archive.org/web/20100228012139/ \
69 * tf.nist.gov/timefreq/service/its.htm
70 * https://web.archive.org/web/20100409024302/ \
71 * tf.nist.gov/timefreq/service/firewall.htm
72 *
73 * Usage:
74 * This software synchronises your computer clock only when you issue
75 * it with --synctime. By default, it only display the webserver's clock.
76 *
77 * Written by: Frank (contributed to libcurl)
78 *
79 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
80 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
81 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
82 *
83 * IN NO EVENT SHALL THE AUTHOR OF THIS SOFTWARE BE LIABLE FOR
84 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
85 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
86 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
87 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
88 * OF THIS SOFTWARE.
89 *
90 */
91
92 #include <stdio.h>
93 #include <time.h>
94 #include <curl/curl.h>
95
96 #ifdef _WIN32
97 #include <windows.h>
98 #endif
99
100
101 #define MAX_STRING 256
102 #define MAX_STRING1 MAX_STRING + 1
103
104 #define SYNCTIME_UA "synctime/1.0"
105
106 typedef struct
107 {
108 char http_proxy[MAX_STRING1];
109 char proxy_user[MAX_STRING1];
110 char timeserver[MAX_STRING1];
111 } conf_t;
112
113 const char DefaultTimeServer[3][MAX_STRING1] =
114 {
115 "https://nist.time.gov/",
116 "https://www.google.com/"
117 };
118
119 const char *DayStr[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
120 const char *MthStr[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
121 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
122
123 int ShowAllHeader;
124 int AutoSyncTime;
125 SYSTEMTIME SYSTime;
126 SYSTEMTIME LOCALTime;
127
128 #define HTTP_COMMAND_HEAD 0
129 #define HTTP_COMMAND_GET 1
130
131
SyncTime_CURL_WriteOutput(void * ptr,size_t size,size_t nmemb,void * stream)132 size_t SyncTime_CURL_WriteOutput(void *ptr, size_t size, size_t nmemb,
133 void *stream)
134 {
135 fwrite(ptr, size, nmemb, stream);
136 return (nmemb*size);
137 }
138
SyncTime_CURL_WriteHeader(void * ptr,size_t size,size_t nmemb,void * stream)139 size_t SyncTime_CURL_WriteHeader(void *ptr, size_t size, size_t nmemb,
140 void *stream)
141 {
142 char TmpStr1[26], TmpStr2[26];
143
144 (void)stream;
145
146 if(ShowAllHeader == 1)
147 fprintf(stderr, "%s", (char *)(ptr));
148
149 if(strncmp((char *)(ptr), "Date:", 5) == 0) {
150 if(ShowAllHeader == 0)
151 fprintf(stderr, "HTTP Server. %s", (char *)(ptr));
152
153 if(AutoSyncTime == 1) {
154 *TmpStr1 = 0;
155 *TmpStr2 = 0;
156 if(strlen((char *)(ptr)) > 50) /* Can prevent buffer overflow to
157 TmpStr1 & 2? */
158 AutoSyncTime = 0;
159 else {
160 int RetVal = sscanf((char *)(ptr), "Date: %25s %hu %s %hu %hu:%hu:%hu",
161 TmpStr1, &SYSTime.wDay, TmpStr2, &SYSTime.wYear,
162 &SYSTime.wHour, &SYSTime.wMinute,
163 &SYSTime.wSecond);
164
165 if(RetVal == 7) {
166 int i;
167 SYSTime.wMilliseconds = 500; /* adjust to midpoint, 0.5 sec */
168 for(i = 0; i < 12; i++) {
169 if(strcmp(MthStr[i], TmpStr2) == 0) {
170 SYSTime.wMonth = i + 1;
171 break;
172 }
173 }
174 AutoSyncTime = 3; /* Computer clock is adjusted */
175 }
176 else {
177 AutoSyncTime = 0; /* Error in sscanf() fields conversion */
178 }
179 }
180 }
181 }
182
183 if(strncmp((char *)(ptr), "X-Cache: HIT", 12) == 0) {
184 fprintf(stderr, "ERROR: HTTP Server data is cached."
185 " Server Date is no longer valid.\n");
186 AutoSyncTime = 0;
187 }
188 return (nmemb*size);
189 }
190
SyncTime_CURL_Init(CURL * curl,char * proxy_port,char * proxy_user_password)191 void SyncTime_CURL_Init(CURL *curl, char *proxy_port,
192 char *proxy_user_password)
193 {
194 if(strlen(proxy_port) > 0)
195 curl_easy_setopt(curl, CURLOPT_PROXY, proxy_port);
196
197 if(strlen(proxy_user_password) > 0)
198 curl_easy_setopt(curl, CURLOPT_PROXYUSERPWD, proxy_user_password);
199
200 #ifdef SYNCTIME_UA
201 curl_easy_setopt(curl, CURLOPT_USERAGENT, SYNCTIME_UA);
202 #endif
203 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, SyncTime_CURL_WriteOutput);
204 curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, SyncTime_CURL_WriteHeader);
205 }
206
SyncTime_CURL_Fetch(CURL * curl,char * URL_Str,char * OutFileName,int HttpGetBody)207 int SyncTime_CURL_Fetch(CURL *curl, char *URL_Str, char *OutFileName,
208 int HttpGetBody)
209 {
210 FILE *outfile;
211 CURLcode res;
212
213 outfile = NULL;
214 if(HttpGetBody == HTTP_COMMAND_HEAD)
215 curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
216 else {
217 outfile = fopen(OutFileName, "wb");
218 curl_easy_setopt(curl, CURLOPT_WRITEDATA, outfile);
219 }
220
221 curl_easy_setopt(curl, CURLOPT_URL, URL_Str);
222 res = curl_easy_perform(curl);
223 if(outfile)
224 fclose(outfile);
225 return res; /* (CURLE_OK) */
226 }
227
showUsage(void)228 void showUsage(void)
229 {
230 fprintf(stderr, "SYNCTIME: Synchronising computer clock with time server"
231 " using HTTP protocol.\n");
232 fprintf(stderr, "Usage : SYNCTIME [Option]\n");
233 fprintf(stderr, "Options :\n");
234 fprintf(stderr, " --server=WEBSERVER Use this time server instead"
235 " of default.\n");
236 fprintf(stderr, " --showall Show all HTTP header.\n");
237 fprintf(stderr, " --synctime Synchronising computer clock"
238 " with time server.\n");
239 fprintf(stderr, " --proxy-user=USER[:PASS] Set proxy username and"
240 " password.\n");
241 fprintf(stderr, " --proxy=HOST[:PORT] Use HTTP proxy on given"
242 " port.\n");
243 fprintf(stderr, " --help Print this help.\n");
244 fprintf(stderr, "\n");
245 return;
246 }
247
conf_init(conf_t * conf)248 int conf_init(conf_t *conf)
249 {
250 int i;
251
252 *conf->http_proxy = 0;
253 for(i = 0; i < MAX_STRING1; i++)
254 conf->proxy_user[i] = 0; /* Clean up password from memory */
255 *conf->timeserver = 0;
256 return 1;
257 }
258
main(int argc,char * argv[])259 int main(int argc, char *argv[])
260 {
261 CURL *curl;
262 conf_t conf[1];
263 int RetValue;
264
265 ShowAllHeader = 0; /* Do not show HTTP Header */
266 AutoSyncTime = 0; /* Do not synchronise computer clock */
267 RetValue = 0; /* Successful Exit */
268 conf_init(conf);
269
270 if(argc > 1) {
271 int OptionIndex = 0;
272 while(OptionIndex < argc) {
273 if(strncmp(argv[OptionIndex], "--server=", 9) == 0)
274 snprintf(conf->timeserver, MAX_STRING, "%s", &argv[OptionIndex][9]);
275
276 if(strcmp(argv[OptionIndex], "--showall") == 0)
277 ShowAllHeader = 1;
278
279 if(strcmp(argv[OptionIndex], "--synctime") == 0)
280 AutoSyncTime = 1;
281
282 if(strncmp(argv[OptionIndex], "--proxy-user=", 13) == 0)
283 snprintf(conf->proxy_user, MAX_STRING, "%s", &argv[OptionIndex][13]);
284
285 if(strncmp(argv[OptionIndex], "--proxy=", 8) == 0)
286 snprintf(conf->http_proxy, MAX_STRING, "%s", &argv[OptionIndex][8]);
287
288 if((strcmp(argv[OptionIndex], "--help") == 0) ||
289 (strcmp(argv[OptionIndex], "/?") == 0)) {
290 showUsage();
291 return 0;
292 }
293 OptionIndex++;
294 }
295 }
296
297 if(*conf->timeserver == 0) /* Use default server for time information */
298 snprintf(conf->timeserver, MAX_STRING, "%s", DefaultTimeServer[0]);
299
300 /* Init CURL before usage */
301 curl_global_init(CURL_GLOBAL_ALL);
302 curl = curl_easy_init();
303 if(curl) {
304 struct tm *lt;
305 struct tm *gmt;
306 time_t tt;
307 time_t tt_local;
308 time_t tt_gmt;
309 double tzonediffFloat;
310 int tzonediffWord;
311 char timeBuf[61];
312 char tzoneBuf[16];
313
314 SyncTime_CURL_Init(curl, conf->http_proxy, conf->proxy_user);
315
316 /* Calculating time diff between GMT and localtime */
317 tt = time(0);
318 lt = localtime(&tt);
319 tt_local = mktime(lt);
320 gmt = gmtime(&tt);
321 tt_gmt = mktime(gmt);
322 tzonediffFloat = difftime(tt_local, tt_gmt);
323 tzonediffWord = (int)(tzonediffFloat/3600.0);
324
325 if((double)(tzonediffWord * 3600) == tzonediffFloat)
326 snprintf(tzoneBuf, 15, "%+03d'00'", tzonediffWord);
327 else
328 snprintf(tzoneBuf, 15, "%+03d'30'", tzonediffWord);
329
330 /* Get current system time and local time */
331 GetSystemTime(&SYSTime);
332 GetLocalTime(&LOCALTime);
333 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
334 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
335 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
336 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
337 LOCALTime.wMilliseconds);
338
339 fprintf(stderr, "Fetch: %s\n\n", conf->timeserver);
340 fprintf(stderr, "Before HTTP. Date: %s%s\n\n", timeBuf, tzoneBuf);
341
342 /* HTTP HEAD command to the Webserver */
343 SyncTime_CURL_Fetch(curl, conf->timeserver, "index.htm",
344 HTTP_COMMAND_HEAD);
345
346 GetLocalTime(&LOCALTime);
347 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
348 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
349 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
350 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
351 LOCALTime.wMilliseconds);
352 fprintf(stderr, "\nAfter HTTP. Date: %s%s\n", timeBuf, tzoneBuf);
353
354 if(AutoSyncTime == 3) {
355 /* Synchronising computer clock */
356 if(!SetSystemTime(&SYSTime)) { /* Set system time */
357 fprintf(stderr, "ERROR: Unable to set system time.\n");
358 RetValue = 1;
359 }
360 else {
361 /* Successfully re-adjusted computer clock */
362 GetLocalTime(&LOCALTime);
363 snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
364 DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
365 MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
366 LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
367 LOCALTime.wMilliseconds);
368 fprintf(stderr, "\nNew System's Date: %s%s\n", timeBuf, tzoneBuf);
369 }
370 }
371
372 /* Cleanup before exit */
373 conf_init(conf);
374 curl_easy_cleanup(curl);
375 }
376 return RetValue;
377 }
378
