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 <string.h>
24#include <curl/curl.h>
25
26/* This is a simple example showing how to send mail using libcurl's SMTP
27 * capabilities. It builds on the smtp-mail.c example to add authentication
28 * and, more importantly, transport security to protect the authentication
29 * details from being snooped.
30 *
31 * Note that this example requires libcurl 7.20.0 or above.
32 */
33
34#define FROM    "<sender@example.org>"
35#define TO      "<addressee@example.net>"
36#define CC      "<info@example.org>"
37
38static const char *payload_text[] = {
39  "Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n",
40  "To: " TO "\r\n",
41  "From: " FROM "(Example User)\r\n",
42  "Cc: " CC "(Another example User)\r\n",
43  "Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@rfcpedant.example.org>\r\n",
44  "Subject: SMTP TLS example message\r\n",
45  "\r\n", /* empty line to divide headers from body, see RFC5322 */
46  "The body of the message starts here.\r\n",
47  "\r\n",
48  "It could be a lot of lines, could be MIME encoded, whatever.\r\n",
49  "Check RFC5322.\r\n",
50  NULL
51};
52
53struct upload_status {
54  int lines_read;
55};
56
57static size_t payload_source(void *ptr, size_t size, size_t nmemb, void *userp)
58{
59  struct upload_status *upload_ctx = (struct upload_status *)userp;
60  const char *data;
61
62  if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
63    return 0;
64  }
65
66  data = payload_text[upload_ctx->lines_read];
67
68  if(data) {
69    size_t len = strlen(data);
70    memcpy(ptr, data, len);
71    upload_ctx->lines_read++;
72
73    return len;
74  }
75
76  return 0;
77}
78
79int main(void)
80{
81  CURL *curl;
82  CURLcode res = CURLE_OK;
83  struct curl_slist *recipients = NULL;
84  struct upload_status upload_ctx;
85
86  upload_ctx.lines_read = 0;
87
88  curl = curl_easy_init();
89  if(curl) {
90    /* Set username and password */
91    curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
92    curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
93
94    /* This is the URL for your mailserver. Note the use of port 587 here,
95     * instead of the normal SMTP port (25). Port 587 is commonly used for
96     * secure mail submission (see RFC4403), but you should use whatever
97     * matches your server configuration. */
98    curl_easy_setopt(curl, CURLOPT_URL, "smtp://mainserver.example.net:587");
99
100    /* In this example, we'll start with a plain text connection, and upgrade
101     * to Transport Layer Security (TLS) using the STARTTLS command. Be careful
102     * of using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer
103     * will continue anyway - see the security discussion in the libcurl
104     * tutorial for more details. */
105    curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
106
107    /* If your server doesn't have a valid certificate, then you can disable
108     * part of the Transport Layer Security protection by setting the
109     * CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST options to 0 (false).
110     *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
111     *   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
112     * That is, in general, a bad idea. It is still better than sending your
113     * authentication details in plain text though.
114     * Instead, you should get the issuer certificate (or the host certificate
115     * if the certificate is self-signed) and add it to the set of certificates
116     * that are known to libcurl using CURLOPT_CAINFO and/or CURLOPT_CAPATH. See
117     * docs/SSLCERTS for more information. */
118    curl_easy_setopt(curl, CURLOPT_CAINFO, "/path/to/certificate.pem");
119
120    /* Note that this option isn't strictly required, omitting it will result in
121     * libcurl sending the MAIL FROM command with empty sender data. All
122     * autoresponses should have an empty reverse-path, and should be directed
123     * to the address in the reverse-path which triggered them. Otherwise, they
124     * could cause an endless loop. See RFC 5321 Section 4.5.5 for more details.
125     */
126    curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM);
127
128    /* Add two recipients, in this particular case they correspond to the
129     * To: and Cc: addressees in the header, but they could be any kind of
130     * recipient. */
131    recipients = curl_slist_append(recipients, TO);
132    recipients = curl_slist_append(recipients, CC);
133    curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
134
135    /* We're using a callback function to specify the payload (the headers and
136     * body of the message). You could just use the CURLOPT_READDATA option to
137     * specify a FILE pointer to read from. */
138    curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
139    curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
140    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
141
142    /* Since the traffic will be encrypted, it is very useful to turn on debug
143     * information within libcurl to see what is happening during the transfer.
144     */
145    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
146
147    /* Send the message */
148    res = curl_easy_perform(curl);
149
150    /* Check for errors */
151    if(res != CURLE_OK)
152      fprintf(stderr, "curl_easy_perform() failed: %s\n",
153              curl_easy_strerror(res));
154
155    /* Free the list of recipients */
156    curl_slist_free_all(recipients);
157
158    /* Always cleanup */
159    curl_easy_cleanup(curl);
160  }
161
162  return (int)res;
163}
164