1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2014, 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 http://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 #include <stdio.h>
23 #include <curl/curl.h>
24 
25 /* This is a simple example showing how to retrieve mail using libcurl's POP3
26  * capabilities. It builds on the pop3-retr.c example adding transport
27  * security to protect the authentication details from being snooped.
28  *
29  * Note that this example requires libcurl 7.20.0 or above.
30  */
31 
main(void)32 int main(void)
33 {
34   CURL *curl;
35   CURLcode res = CURLE_OK;
36 
37   curl = curl_easy_init();
38   if(curl) {
39     /* Set username and password */
40     curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
41     curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
42 
43     /* This will retrieve message 1 from the user's mailbox */
44     curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1");
45 
46     /* In this example, we'll start with a plain text connection, and upgrade
47      * to Transport Layer Security (TLS) using the STLS command. Be careful of
48      * using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer
49      * will continue anyway - see the security discussion in the libcurl
50      * tutorial for more details. */
51     curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
52 
53     /* If your server doesn't have a valid certificate, then you can disable
54      * part of the Transport Layer Security protection by setting the
55      * CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST options to 0 (false).
56      *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
57      *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
58      * That is, in general, a bad idea. It is still better than sending your
59      * authentication details in plain text though.
60      * Instead, you should get the issuer certificate (or the host certificate
61      * if the certificate is self-signed) and add it to the set of certificates
62      * that are known to libcurl using CURLOPT_CAINFO and/or CURLOPT_CAPATH. See
63      * docs/SSLCERTS for more information. */
64     curl_easy_setopt(curl, CURLOPT_CAINFO, "/path/to/certificate.pem");
65 
66     /* Since the traffic will be encrypted, it is very useful to turn on debug
67      * information within libcurl to see what is happening during the
68      * transfer */
69     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
70 
71     /* Perform the retr */
72     res = curl_easy_perform(curl);
73 
74     /* Check for errors */
75     if(res != CURLE_OK)
76       fprintf(stderr, "curl_easy_perform() failed: %s\n",
77               curl_easy_strerror(res));
78 
79     /* Always cleanup */
80     curl_easy_cleanup(curl);
81   }
82 
83   return (int)res;
84 }
85