1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2016, 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
41static 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
52static 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
58int 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