ARM平台移植libcurl curl-7.49.0

libcurl是免费的轻量级的客户端网络库，支持DICT, FILE, FTP, FTPS, Gopher, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS,POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS, Telnet, TFTP.支持SSL, HTTPPOST,HTTPPUT, FTP上传, HTTP form上传，代理，cookies, 用户名与密码认证。

系统环境：Ubuntu 14.04.3 LTS
源码：curl-7.49.0.tar.gz （https://curl.haxx.se/download.html） 交叉编译环境：arm-none-linux-gnueabi-
[zhaojq@virtual-machine]# tar -zxvf curl-7.49.0.tar.gz
[zhaojq@virtual-machine]# cd curl-7.49.0/
[zhaojq@virtual-machine]# ./configure --prefix=/home/zhaojq/libcurl --host=arm-none-linux CC=arm-none-linux-gnueabi-gcc CXX=arm-none-linux-gnueabi-g++
[zhaojq@virtual-machine]# make
[zhaojq@virtual-machine]# make install
生成成功

交叉编译后的文件在/home/zhaojq/libcurl目录下
[zhaojq@virtual-machine libcurl]# ls
bin  include  lib  share

libcurl头文件在include/curl目录
[zhaojq@virtual-machine libcurl/include/curl]# ls
curlbuild.h  curl.h  curlrules.h  curlver.h  easy.h  mprintf.h  multi.h  stdcheaders.h  typecheck-gcc.h

交叉编译后的动态库文件在lib目录
[zhaojq@virtual-machine libcurl/lib]# ls
libcurl.a  libcurl.la  libcurl.so  libcurl.so.4  libcurl.so.4.4.0  pkgconfig

编译test实例 https://curl.haxx.se/libcurl/c/example.html

post-callback

An example source code that issues a HTTP POST and we provide the actual data through a read callback.

[zhaojq@virtual-machine]# vim libcurl_test.cpp

#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
 
const char data[]="this is what we post to the silly web server";
 
struct WriteThis {
  const char *readptr;
  long sizeleft;
};
 
static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *userp)
{
  struct WriteThis *pooh = (struct WriteThis *)userp;
 
  if(size*nmemb < 1)
    return 0;
 
  if(pooh->sizeleft) {
    *(char *)ptr = pooh->readptr[0]; /* copy one single byte */ 
    pooh->readptr++;                 /* advance pointer */ 
    pooh->sizeleft--;                /* less data left */ 
    return 1;                        /* we return 1 byte at a time! */ 
  }
 
  return 0;                          /* no more data left to deliver */ 
}
 
int main(void)
{
  CURL *curl;
  CURLcode res;
 
  struct WriteThis pooh;
 
  pooh.readptr = data;
  pooh.sizeleft = (long)strlen(data);
 
  /* In windows, this will init the winsock stuff */ 
  res = curl_global_init(CURL_GLOBAL_DEFAULT);
  /* Check for errors */ 
  if(res != CURLE_OK) {
    fprintf(stderr, "curl_global_init() failed: %s
",
            curl_easy_strerror(res));
    return 1;
  }
 
  /* get a curl handle */ 
  curl = curl_easy_init();
  if(curl) {
    /* First set the URL that is about to receive our POST. */ 
    curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/index.cgi");
 
    /* Now specify we want to POST data */ 
    curl_easy_setopt(curl, CURLOPT_POST, 1L);
 
    /* we want to use our own read function */ 
    curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
 
    /* pointer to pass to our read function */ 
    curl_easy_setopt(curl, CURLOPT_READDATA, &pooh);
 
    /* get verbose debug output please */ 
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
 
    /*
      If you use POST to a HTTP 1.1 server, you can send data without knowing
      the size before starting the POST if you use chunked encoding. You
      enable this by adding a header like "Transfer-Encoding: chunked" with
      CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
      specify the size in the request.
    */ 
#ifdef USE_CHUNKED
    {
      struct curl_slist *chunk = NULL;
 
      chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
      res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
      /* use curl_slist_free_all() after the *perform() call to free this
         list again */ 
    }
#else
    /* Set the expected POST size. If you want to POST large amounts of data,
       consider CURLOPT_POSTFIELDSIZE_LARGE */ 
    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, pooh.sizeleft);
#endif
 
#ifdef DISABLE_EXPECT
    /*
      Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue"
      header.  You can disable this header with CURLOPT_HTTPHEADER as usual.
      NOTE: if you want chunked transfer too, you need to combine these two
      since you can only set one list of headers with CURLOPT_HTTPHEADER. */ 
 
    /* A less good option would be to enforce HTTP 1.0, but that might also
       have other implications. */ 
    {
      struct curl_slist *chunk = NULL;
 
      chunk = curl_slist_append(chunk, "Expect:");
      res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
      /* use curl_slist_free_all() after the *perform() call to free this
         list again */ 
    }
#endif
 
    /* Perform the request, res will get the return code */ 
    res = curl_easy_perform(curl);
    /* Check for errors */ 
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s
",
              curl_easy_strerror(res));
 
    /* always cleanup */ 
    curl_easy_cleanup(curl);
  }
  curl_global_cleanup();
  return 0;
}

[zhaojq@virtual-machine]# arm-none-linux-gnueabi-g++ -lcurl -I/home/kt/libcurl/include -L/home/kt/libcurl/lib -o libcurl_test libcurl.cpp
编译通过，在当前目录生成libcurl_test可执行文件
将/home/zhaojq/libcurl目录下的所有文件和pkgconfig目录都拷贝到ARM设备上文件系统的/lib目录，
将libcurl_test拷贝到ARM设备上
执行./libcurl_test
./libcurl_test: error while loading shared libraries: libssl.so.1.0.0: cannot open shared object file: No such file or directory
libcurl运行需要libssl.so.1.0.0的库，ARM移植openssl-1.0.0s.tar.gz详见另一篇文章 http://blog.csdn.net/miaodichiyou/article/details/50385049



移植成功再次执行./libcurl_test
[root@ARM /]# ./libcurl_test 
*   Trying 93.184.216.34...
* Connected to example.com (93.184.216.34) port 80 (#0)
> POST /index.cgi HTTP/1.1
Host: example.com
Accept: */*
Content-Length: 44
Content-Type: application/x-www-form-urlencoded


* We are completely uploaded and fine
< HTTP/1.1 404 Not Found
< Cache-Control: max-age=604800
< Content-Type: text/html
< Date: Thu, 19 May 2016 02:45:50 GMT
< Expires: Thu, 26 May 2016 02:45:50 GMT
< Server: EOS (lax004/2813)
< Content-Length: 460
< 
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
        <head>
                <title>404 - Not Found</title>
        </head>
        <body>
                <h1>404 - Not Found</h1>
                <script type="text/javascript" src="http://gp1.wpc.edgecastcdn.net/00222B/jtest/pilot_dns_best_pop.js"></script>
        </body>
</html>
* Connection #0 to host example.com left intact
移植成功。