1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2017, 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
23 /* <DESC>
24 * POP3 example using the multi interface
25 * </DESC>
26 */
27
28 #include <stdio.h>
29 #include <string.h>
30 #include <curl/curl.h>
31
32 /* This is a simple example showing how to retrieve mail using libcurl's POP3
33 * capabilities. It builds on the pop3-retr.c example to demonstrate how to use
34 * libcurl's multi interface.
35 *
36 * Note that this example requires libcurl 7.20.0 or above.
37 */
38
39 #define MULTI_PERFORM_HANG_TIMEOUT 60 * 1000
40
tvnow(void)41 static struct timeval tvnow(void)
42 {
43 struct timeval now;
44
45 /* time() returns the value of time in seconds since the epoch */
46 now.tv_sec = (long)time(NULL);
47 now.tv_usec = 0;
48
49 return now;
50 }
51
tvdiff(struct timeval newer,struct timeval older)52 static long tvdiff(struct timeval newer, struct timeval older)
53 {
54 return (newer.tv_sec - older.tv_sec) * 1000 +
55 (newer.tv_usec - older.tv_usec) / 1000;
56 }
57
main(void)58 int main(void)
59 {
60 CURL *curl;
61 CURLM *mcurl;
62 int still_running = 1;
63 struct timeval mp_start;
64
65 curl_global_init(CURL_GLOBAL_DEFAULT);
66
67 curl = curl_easy_init();
68 if(!curl)
69 return 1;
70
71 mcurl = curl_multi_init();
72 if(!mcurl)
73 return 2;
74
75 /* Set username and password */
76 curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
77 curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
78
79 /* This will retrieve message 1 from the user's mailbox */
80 curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1");
81
82 /* Tell the multi stack about our easy handle */
83 curl_multi_add_handle(mcurl, curl);
84
85 /* Record the start time which we can use later */
86 mp_start = tvnow();
87
88 /* We start some action by calling perform right away */
89 curl_multi_perform(mcurl, &still_running);
90
91 while(still_running) {
92 struct timeval timeout;
93 fd_set fdread;
94 fd_set fdwrite;
95 fd_set fdexcep;
96 int maxfd = -1;
97 int rc;
98 CURLMcode mc; /* curl_multi_fdset() return code */
99
100 long curl_timeo = -1;
101
102 /* Initialise the file descriptors */
103 FD_ZERO(&fdread);
104 FD_ZERO(&fdwrite);
105 FD_ZERO(&fdexcep);
106
107 /* Set a suitable timeout to play around with */
108 timeout.tv_sec = 1;
109 timeout.tv_usec = 0;
110
111 curl_multi_timeout(mcurl, &curl_timeo);
112 if(curl_timeo >= 0) {
113 timeout.tv_sec = curl_timeo / 1000;
114 if(timeout.tv_sec > 1)
115 timeout.tv_sec = 1;
116 else
117 timeout.tv_usec = (curl_timeo % 1000) * 1000;
118 }
119
120 /* get file descriptors from the transfers */
121 mc = curl_multi_fdset(mcurl, &fdread, &fdwrite, &fdexcep, &maxfd);
122
123 if(mc != CURLM_OK) {
124 fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
125 break;
126 }
127
128 /* On success the value of maxfd is guaranteed to be >= -1. We call
129 select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
130 no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
131 to sleep 100ms, which is the minimum suggested value in the
132 curl_multi_fdset() doc. */
133
134 if(maxfd == -1) {
135 #ifdef _WIN32
136 Sleep(100);
137 rc = 0;
138 #else
139 /* Portable sleep for platforms other than Windows. */
140 struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
141 rc = select(0, NULL, NULL, NULL, &wait);
142 #endif
143 }
144 else {
145 /* Note that on some platforms 'timeout' may be modified by select().
146 If you need access to the original value save a copy beforehand. */
147 rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
148 }
149
150 if(tvdiff(tvnow(), mp_start) > MULTI_PERFORM_HANG_TIMEOUT) {
151 fprintf(stderr,
152 "ABORTING: Since it seems that we would have run forever.\n");
153 break;
154 }
155
156 switch(rc) {
157 case -1: /* select error */
158 break;
159 case 0: /* timeout */
160 default: /* action */
161 curl_multi_perform(mcurl, &still_running);
162 break;
163 }
164 }
165
166 /* Always cleanup */
167 curl_multi_remove_handle(mcurl, curl);
168 curl_multi_cleanup(mcurl);
169 curl_easy_cleanup(curl);
170 curl_global_cleanup();
171
172 return 0;
173 }
174