Annotation of embedaddon/curl/docs/examples/synctime.c, revision 1.1.1.1
1.1 misho 1: /***************************************************************************
2: * _ _ ____ _
3: * Project ___| | | | _ \| |
4: * / __| | | | |_) | |
5: * | (__| |_| | _ <| |___
6: * \___|\___/|_| \_\_____|
7: *
8: * Copyright (C) 1998 - 2019, 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:
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:
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:
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:
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:
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:
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:
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: }
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