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