CMakeLua/Utilities/cmcurl-7.19.0/docs/examples/synctime.c

   1 /*****************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
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   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * $Id: synctime.c,v 1.1.1.1 2008-09-23 16:32:05 hoffman Exp $
   9  *
  10  * This example code only builds as-is on Windows.
  11  *
  12  * While Unix/Linux user, you do not need this software.
  13  * You can achieve the same result as synctime using curl, awk and date.
  14  * Set proxy as according to your network, but beware of proxy Cache-Control.
  15  *
  16  * To set your system clock, root access is required.
  17  * # date -s "`curl -sI http://nist.time.gov/timezone.cgi?UTC/s/0 \
  18  *        | awk -F': ' '/Date: / {print $2}'`"
  19  *
  20  * To view remote webserver date and time.
  21  * $ curl -sI http://nist.time.gov/timezone.cgi?UTC/s/0 \
  22  *        | awk -F': ' '/Date: / {print $2}'
  23  *
  24  * Synchronising your computer clock via Internet time server usually relies
  25  * on DAYTIME, TIME, or NTP protocols. These protocols provide good accurate
  26  * time synchronisation but it does not work very well through a
  27  * firewall/proxy. Some adjustment has to be made to the firewall/proxy for
  28  * these protocols to work properly.
  29  *
  30  * There is an indirect method. Since most webserver provide server time in
  31  * their HTTP header, therefore you could synchronise your computer clock
  32  * using HTTP protocol which has no problem with firewall/proxy.
  33  *
  34  * For this software to work, you should take note of these items.
  35  * 1. Your firewall/proxy must allow your computer to surf internet.
  36  * 2. Webserver system time must in sync with the NTP time server,
  37  *    or at least provide an accurate time keeping.
  38  * 3. Webserver HTTP header does not provide the milliseconds units,
  39  *    so there is no way to get very accurate time.
  40  * 4. This software could only provide an accuracy of +- a few seconds,
  41  *    as Round-Trip delay time is not taken into consideration.
  42  *    Compensation of network, firewall/proxy delay cannot be simply divide
  43  *    the Round-Trip delay time by half.
  44  * 5. Win32 SetSystemTime() API will set your computer clock according to
  45  *    GMT/UTC time. Therefore your computer timezone must be properly set.
  46  * 6. Webserver data should not be cached by the proxy server. Some
  47  *    webserver provide Cache-Control to prevent caching.
  48  *
  49  * References:
  50  * http://tf.nist.gov/timefreq/service/its.htm
  51  * http://tf.nist.gov/timefreq/service/firewall.htm
  52  *
  53  * Usage:
  54  * This software will synchronise your computer clock only when you issue
  55  * it with --synctime. By default, it only display the webserver's clock.
  56  *
  57  * Written by: Frank (contributed to libcurl)
  58  *
  59  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  60  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  61  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  62  *
  63  * IN NO EVENT SHALL THE AUTHOR OF THIS SOFTWARE BE LIABLE FOR
  64  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  65  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  66  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  67  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  68  * OF THIS SOFTWARE.
  69  *
  70  */
  71
  72 #include <stdio.h>
  73 #include <time.h>
  74 #ifndef __CYGWIN__
  75 #include <windows.h>
  76 #endif
  77 #include <curl/curl.h>
  78
  79
  80 #define MAX_STRING              256
  81 #define MAX_STRING1             MAX_STRING+1
  82
  83 typedef struct
  84 {
  85   char http_proxy[MAX_STRING1];
  86   char proxy_user[MAX_STRING1];
  87   char timeserver[MAX_STRING1];
  88 } conf_t;
  89
  90 const char DefaultTimeServer[4][MAX_STRING1] =
  91 {
  92   "http://nist.time.gov/timezone.cgi?UTC/s/0",
  93   "http://www.google.com/",
  94   "http://www.worldtimeserver.com/current_time_in_UTC.aspx",
  95   "http://www.worldtime.com/cgi-bin/wt.cgi"
  96 };
  97
  98 const char *DayStr[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
  99 const char *MthStr[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 100                         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 101
 102 int  ShowAllHeader;
 103 int  AutoSyncTime;
 104 SYSTEMTIME SYSTime;
 105 SYSTEMTIME LOCALTime;
 106
 107 #define HTTP_COMMAND_HEAD       0
 108 #define HTTP_COMMAND_GET        1
 109
 110
 111 size_t SyncTime_CURL_WriteOutput(void *ptr, size_t size, size_t nmemb,
 112                                  void *stream)
 113 {
 114   fwrite(ptr, size, nmemb, stream);
 115   return(nmemb*size);
 116 }
 117
 118 size_t SyncTime_CURL_WriteHeader(void *ptr, size_t size, size_t nmemb,
 119                                  void *stream)
 120 {
 121   int   i, RetVal;
 122   char  TmpStr1[26], TmpStr2[26];
 123
 124   if (ShowAllHeader == 1)
 125     fprintf(stderr, "%s", (char *)(ptr));
 126
 127   if (strncmp((char *)(ptr), "Date:", 5) == 0) {
 128     if (ShowAllHeader == 0)
 129       fprintf(stderr, "HTTP Server. %s", (char *)(ptr));
 130
 131     if (AutoSyncTime == 1) {
 132       *TmpStr1 = 0;
 133       *TmpStr2 = 0;
 134       if (strlen((char *)(ptr)) > 50) /* Can prevent buffer overflow to
 135                                          TmpStr1 & 2? */
 136         AutoSyncTime = 0;
 137       else {
 138         RetVal = sscanf ((char *)(ptr), "Date: %s %d %s %d %d:%d:%d",
 139                          TmpStr1, &SYSTime.wDay, TmpStr2, &SYSTime.wYear,
 140                          &SYSTime.wHour, &SYSTime.wMinute, &SYSTime.wSecond);
 141
 142         if (RetVal == 7) {
 143
 144           SYSTime.wMilliseconds = 500;    /* adjust to midpoint, 0.5 sec */
 145           for (i=0; i<12; i++) {
 146             if (strcmp(MthStr[i], TmpStr2) == 0) {
 147               SYSTime.wMonth = i+1;
 148               break;
 149             }
 150           }
 151           AutoSyncTime = 3;       /* Computer clock will be adjusted */
 152         }
 153         else {
 154           AutoSyncTime = 0;       /* Error in sscanf() fields conversion */
 155         }
 156       }
 157     }
 158   }
 159
 160   if (strncmp((char *)(ptr), "X-Cache: HIT", 12) == 0) {
 161     fprintf(stderr, "ERROR: HTTP Server data is cached."
 162             " Server Date is no longer valid.\n");
 163     AutoSyncTime = 0;
 164   }
 165   return(nmemb*size);
 166 }
 167
 168 void SyncTime_CURL_Init(CURL *curl, char *proxy_port,
 169                         char *proxy_user_password)
 170 {
 171   if (strlen(proxy_port) > 0)
 172     curl_easy_setopt(curl, CURLOPT_PROXY, proxy_port);
 173
 174   if (strlen(proxy_user_password) > 0)
 175     curl_easy_setopt(curl, CURLOPT_PROXYUSERPWD, proxy_user_password);
 176
 177   /* Trick Webserver by claiming that you are using Microsoft WinXP SP2, IE6 */
 178   curl_easy_setopt(curl, CURLOPT_USERAGENT,
 179                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
 180   curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, *SyncTime_CURL_WriteOutput);
 181   curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, *SyncTime_CURL_WriteHeader);
 182 }
 183
 184 int SyncTime_CURL_Fetch(CURL *curl, char *URL_Str, char *OutFileName,
 185                         int HttpGetBody)
 186 {
 187   FILE *outfile;
 188   CURLcode res;
 189
 190   outfile = NULL;
 191   if (HttpGetBody == HTTP_COMMAND_HEAD)
 192     curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
 193   else {
 194     outfile = fopen(OutFileName, "wb");
 195     curl_easy_setopt(curl, CURLOPT_WRITEDATA, outfile);
 196   }
 197
 198   curl_easy_setopt(curl, CURLOPT_URL, URL_Str);
 199   res = curl_easy_perform(curl);
 200   if (outfile != NULL)
 201     fclose(outfile);
 202   return res;  /* (CURLE_OK) */
 203 }
 204
 205 void showUsage(void)
 206 {
 207   fprintf(stderr, "SYNCTIME: Synchronising computer clock with time server"
 208           " using HTTP protocol.\n");
 209   fprintf(stderr, "Usage   : SYNCTIME [Option]\n");
 210   fprintf(stderr, "Options :\n");
 211   fprintf(stderr, " --server=WEBSERVER        Use this time server instead"
 212           " of default.\n");
 213   fprintf(stderr, " --showall                 Show all HTTP header.\n");
 214   fprintf(stderr, " --synctime                Synchronising computer clock"
 215           " with time server.\n");
 216   fprintf(stderr, " --proxy-user=USER[:PASS]  Set proxy username and"
 217           " password.\n");
 218   fprintf(stderr, " --proxy=HOST[:PORT]       Use HTTP proxy on given"
 219           " port.\n");
 220   fprintf(stderr, " --help                    Print this help.\n");
 221   fprintf(stderr, "\n");
 222   return;
 223 }
 224
 225 int conf_init(conf_t *conf)
 226 {
 227   int i;
 228
 229   *conf->http_proxy       = 0;
 230   for (i=0; i<MAX_STRING1; i++)
 231     conf->proxy_user[i]     = 0;    /* Clean up password from memory */
 232   *conf->timeserver       = 0;
 233   return 1;
 234 }
 235
 236 int main(int argc, char *argv[])
 237 {
 238   CURL    *curl;
 239   conf_t  conf[1];
 240   int     OptionIndex;
 241   struct  tm *lt;
 242   struct  tm *gmt;
 243   time_t  tt;
 244   time_t  tt_local;
 245   time_t  tt_gmt;
 246   double  tzonediffFloat;
 247   int     tzonediffWord;
 248   char    timeBuf[61];
 249   char    tzoneBuf[16];
 250   int     RetValue;
 251
 252   OptionIndex     = 0;
 253   ShowAllHeader   = 0;    /* Do not show HTTP Header */
 254   AutoSyncTime    = 0;    /* Do not synchronise computer clock */
 255   RetValue        = 0;    /* Successful Exit */
 256   conf_init(conf);
 257
 258   if (argc > 1) {
 259     while (OptionIndex < argc) {
 260       if (strncmp(argv[OptionIndex], "--server=", 9) == 0)
 261         snprintf(conf->timeserver, MAX_STRING, "%s", &argv[OptionIndex][9]);
 262
 263       if (strcmp(argv[OptionIndex], "--showall") == 0)
 264         ShowAllHeader = 1;
 265
 266       if (strcmp(argv[OptionIndex], "--synctime") == 0)
 267         AutoSyncTime = 1;
 268
 269       if (strncmp(argv[OptionIndex], "--proxy-user=", 13) == 0)
 270         snprintf(conf->proxy_user, MAX_STRING, "%s", &argv[OptionIndex][13]);
 271
 272       if (strncmp(argv[OptionIndex], "--proxy=", 8) == 0)
 273         snprintf(conf->http_proxy, MAX_STRING, "%s", &argv[OptionIndex][8]);
 274
 275       if ((strcmp(argv[OptionIndex], "--help") == 0) ||
 276           (strcmp(argv[OptionIndex], "/?") == 0)) {
 277         showUsage();
 278         return 0;
 279       }
 280       OptionIndex++;
 281     }
 282   }
 283
 284   if (*conf->timeserver == 0)     /* Use default server for time information */
 285     snprintf(conf->timeserver, MAX_STRING, "%s", DefaultTimeServer[0]);
 286
 287   /* Init CURL before usage */
 288   curl_global_init(CURL_GLOBAL_ALL);
 289   curl = curl_easy_init();
 290   if (curl) {
 291     SyncTime_CURL_Init(curl, conf->http_proxy, conf->proxy_user);
 292
 293     /* Calculating time diff between GMT and localtime */
 294     tt       = time(0);
 295     lt       = localtime(&tt);
 296     tt_local = mktime(lt);
 297     gmt      = gmtime(&tt);
 298     tt_gmt   = mktime(gmt);
 299     tzonediffFloat = difftime(tt_local, tt_gmt);
 300     tzonediffWord  = (int)(tzonediffFloat/3600.0);
 301
 302     if ((double)(tzonediffWord * 3600) == tzonediffFloat)
 303       snprintf(tzoneBuf, 15, "%+03d'00'", tzonediffWord);
 304     else
 305       snprintf(tzoneBuf, 15, "%+03d'30'", tzonediffWord);
 306
 307     /* Get current system time and local time */
 308     GetSystemTime(&SYSTime);
 309     GetLocalTime(&LOCALTime);
 310     snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
 311              DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
 312              MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
 313              LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
 314              LOCALTime.wMilliseconds);
 315
 316     fprintf(stderr, "Fetch: %s\n\n", conf->timeserver);
 317     fprintf(stderr, "Before HTTP. Date: %s%s\n\n", timeBuf, tzoneBuf);
 318
 319     /* HTTP HEAD command to the Webserver */
 320     SyncTime_CURL_Fetch(curl, conf->timeserver, "index.htm",
 321                         HTTP_COMMAND_HEAD);
 322
 323     GetLocalTime(&LOCALTime);
 324     snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
 325              DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
 326              MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
 327              LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
 328              LOCALTime.wMilliseconds);
 329     fprintf(stderr, "\nAfter  HTTP. Date: %s%s\n", timeBuf, tzoneBuf);
 330
 331     if (AutoSyncTime == 3) {
 332       /* Synchronising computer clock */
 333       if (!SetSystemTime(&SYSTime)) {  /* Set system time */
 334         fprintf(stderr, "ERROR: Unable to set system time.\n");
 335         RetValue = 1;
 336       }
 337       else {
 338         /* Successfully re-adjusted computer clock */
 339         GetLocalTime(&LOCALTime);
 340         snprintf(timeBuf, 60, "%s, %02d %s %04d %02d:%02d:%02d.%03d, ",
 341                  DayStr[LOCALTime.wDayOfWeek], LOCALTime.wDay,
 342                  MthStr[LOCALTime.wMonth-1], LOCALTime.wYear,
 343                  LOCALTime.wHour, LOCALTime.wMinute, LOCALTime.wSecond,
 344                  LOCALTime.wMilliseconds);
 345         fprintf(stderr, "\nNew System's Date: %s%s\n", timeBuf, tzoneBuf);
 346       }
 347     }
 348
 349     /* Cleanup before exit */
 350     conf_init(conf);
 351     curl_easy_cleanup(curl);
 352   }
 353   return RetValue;
 354 }