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 will set 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 will synchronise 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 106typedef struct 107{ 108 char http_proxy[MAX_STRING1]; 109 char proxy_user[MAX_STRING1]; 110 char timeserver[MAX_STRING1]; 111} conf_t; 112 113const char DefaultTimeServer[3][MAX_STRING1] = 114{ 115 "https://nist.time.gov/", 116 "https://www.google.com/" 117}; 118 119const char *DayStr[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}; 120const char *MthStr[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", 121 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; 122 123int ShowAllHeader; 124int AutoSyncTime; 125SYSTEMTIME SYSTime; 126SYSTEMTIME LOCALTime; 127 128#define HTTP_COMMAND_HEAD 0 129#define HTTP_COMMAND_GET 1 130 131 132size_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 139size_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 will be 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 191void 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 207int 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 228void 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 248int 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 259int 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