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curl/docs/examples/externalsocket.c
Andre Guibert de Bruet 57c7076793 examples/externalsocket: add missing close socket calls
.. and for Windows also call WSACleanup since we call WSAStartup.

The example is to demonstrate handling the socket independently of
libcurl. In this case libcurl is not responsible for creating, opening
or closing the socket, it is handled by the application (our example).

Fixes https://github.com/curl/curl/pull/3663
2019-03-11 23:02:54 -04:00

175 lines
4.8 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
/* <DESC>
* An example demonstrating how an application can pass in a custom
* socket to libcurl to use. This example also handles the connect itself.
* </DESC>
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <curl/curl.h>
#ifdef WIN32
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#define close closesocket
#else
#include <sys/types.h> /* socket types */
#include <sys/socket.h> /* socket definitions */
#include <netinet/in.h>
#include <arpa/inet.h> /* inet (3) functions */
#include <unistd.h> /* misc. Unix functions */
#endif
#include <errno.h>
/* The IP address and port number to connect to */
#define IPADDR "127.0.0.1"
#define PORTNUM 80
#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif
static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
{
size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
return written;
}
static int closecb(void *clientp, curl_socket_t item)
{
(void)clientp;
printf("libcurl wants to close %d now\n", (int)item);
return 0;
}
static curl_socket_t opensocket(void *clientp,
curlsocktype purpose,
struct curl_sockaddr *address)
{
curl_socket_t sockfd;
(void)purpose;
(void)address;
sockfd = *(curl_socket_t *)clientp;
/* the actual externally set socket is passed in via the OPENSOCKETDATA
option */
return sockfd;
}
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
curlsocktype purpose)
{
(void)clientp;
(void)curlfd;
(void)purpose;
/* This return code was added in libcurl 7.21.5 */
return CURL_SOCKOPT_ALREADY_CONNECTED;
}
int main(void)
{
CURL *curl;
CURLcode res;
struct sockaddr_in servaddr; /* socket address structure */
curl_socket_t sockfd;
#ifdef WIN32
WSADATA wsaData;
int initwsa = WSAStartup(MAKEWORD(2, 0), &wsaData);
if(initwsa != 0) {
printf("WSAStartup failed: %d\n", initwsa);
return 1;
}
#endif
curl = curl_easy_init();
if(curl) {
/*
* Note that libcurl will internally think that you connect to the host
* and port that you specify in the URL option.
*/
curl_easy_setopt(curl, CURLOPT_URL, "http://99.99.99.99:9999");
/* Create the socket "manually" */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd == CURL_SOCKET_BAD) {
printf("Error creating listening socket.\n");
return 3;
}
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(PORTNUM);
servaddr.sin_addr.s_addr = inet_addr(IPADDR);
if(INADDR_NONE == servaddr.sin_addr.s_addr) {
close(sockfd);
return 2;
}
if(connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) ==
-1) {
close(sockfd);
printf("client error: connect: %s\n", strerror(errno));
return 1;
}
/* no progress meter please */
curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
/* send all data to this function */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
/* call this function to get a socket */
curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);
/* call this function to close sockets */
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closecb);
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &sockfd);
/* call this function to set options for the socket */
curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
close(sockfd);
if(res) {
printf("libcurl error: %d\n", res);
return 4;
}
}
#ifdef WIN32
WSACleanup();
#endif
return 0;
}