tags/REL-2.2/ftp_get_buffer.c

/*
  liboftp: this is an FTP library to simplify the work to a Developer
  who want to work with FTP servers (RFC 959).

  Copyright (c) 2009 hirohito higashi. All rights reserved.
  This file is distributed under BSD license.
*/


/***** Feature test switches ************************************************/
/***** System headers *******************************************************/
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <errno.h>


/***** Local headers ********************************************************/
#include "liboftp.h"
#include "sub.h"


/***** Constat values *******************************************************/
#define TRANSFER_SEGMENT_SIZE   4096            /* 一度のrecv()で転送するバイト数 */


/***** Macros ***************************************************************/
/***** Typedefs *************************************************************/
/***** Function prototypes **************************************************/
/***** Local variables ******************************************************/
/***** Global variables *****************************************************/
/***** Signal catching functions ********************************************/
/***** Local functions ******************************************************/
/***** Global functions *****************************************************/

/****************************************************************************/
/*! バッファへファイル取得
 *
 *@param        ftp     LIBOFTPへのポインタ。
 *@param        fname   サーバ上のファイル名
 *@param        buf     バッファへのポインタ
 *@param        bufsiz  バッファサイズ
 *@retval       int     取得したバイト数　マイナス値ならエラーコード
 *@note
 */
int ftp_get_buffer( LIBOFTP *ftp, const char *fname, char *buf, int bufsiz )
{
    int data_socket;
    char *p = buf;
    int res;

    /*
     * 受信準備
     */
    if( ftp->flag_passive ) {
        data_socket = ftp_getready_pasv( ftp, "RETR", fname );
    } else {
        data_socket = ftp_getready_active( ftp, "RETR", fname );
    }
    if( data_socket < 0 ) {
        return data_socket;
    }

    /*
     * タイムアウトが意図通りに働くように、分割してrecvする。
     */
    while( 1 ) {
        int n;
        int len = bufsiz;
        if( len > TRANSFER_SEGMENT_SIZE ) {
            len = TRANSFER_SEGMENT_SIZE;
        }
        n = recv( data_socket, p, len, 0 );
        DEBUGPRINT1( "RECV: n=%d\n", n );
        if( n < 0 ) {
            int ret;
            DEBUGPRINT1( "recv error. %s\n", strerror(errno) );
            if( errno == EAGAIN ) {
                ret = LIBOFTP_ERROR_TIMEOUT;
            } else {
                ret = LIBOFTP_ERROR_OS;
                copy_strerror();
            }
            close( data_socket );
            return ret;
        }
        if( n == 0 ) {
            break;
        }
        p += n;
        bufsiz -= n;
        if( bufsiz <= 0 ) {
            break;              /* buffer too small */
        }
    }

    if( bufsiz > 0 ) {          /* バッファ不足だったか？ */
        /*
         * 不足していない
         */
        close( data_socket );

        /* receive response. */
        res = ftp_receive_response( ftp, ftp->error_message, sizeof(ftp->error_message)-1 );
        if( res != 226 ) {                                              /* 226: Closing data connection. */
            DEBUGPRINT1( "got illegal response %d\n", res );
            return res < 0? res: LIBOFTP_ERROR_PROTOCOL;
        }

        return p - buf;         /* return with transfered bytes */
        
    } else {
        /*
         * バッファ不足時
         */
        DEBUGPRINT1( "buffer too small. %s\n", "" );
        strncpy( ftp->error_message, "buffer too small", sizeof( ftp->error_message ) - 1 );

        if( ftp_send_command( ftp, "ABOR\r\n" ) < 0 ) {
            DEBUGPRINT1( "command sending error. %s\n", "ABOR" );
            close( data_socket );
            return LIBOFTP_ERROR_BUFFER;
        }

        res = ftp_receive_response( ftp, 0, 0 );
        if( res == 426 ) {                                              /* 426: Connection closed; transfer aborted. */
            res = ftp_receive_response( ftp, 0, 0 );
        }
        close( data_socket );
        if( res != 226 ) {                                              /* 226: Closing data connection. */
            DEBUGPRINT1( "got illegal response %d\n", res );
            return res < 0? res: LIBOFTP_ERROR_PROTOCOL;
        }

        return LIBOFTP_ERROR_BUFFER;
    }
}