view/trunk/sub.c

/*
  Some global functions for libOftp.
  
  Copyright (c) 2009-2009 hirohito higashi. All rights reserved.
  This file is distributed under BSD license.
*/


/***** Feature test switches ************************************************/
/***** System headers *******************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/select.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 ******************************************************/
/****************************************************************************/
/*! read a line
 *
 *@param        sd      socket descriptor
 *@param        buf     pointer of receive buffer
 *@param        bufsiz  buffer size
 *@param        flags   flags of recv()
 *@retval       int     number of bytes received, or -1 if an error.
 *@note
 *
 */
static int recv_line( int sd, char *buf, int bufsiz, int flags )
{
    int n;
    char c;
    char *p = buf;
    int total_len = 0;

    bufsiz--;

    while( 1 ) {
        n = recv( sd, &c, 1, flags );
        if( n < 0 ) {
            if( errno == EINTR ) continue;
            *p = 0;
            DEBUGPRINT1( "recv_line: get minus. %s\n", strerror(errno) );
            return n;
        }
        if( n == 0 ) {
            DEBUGPRINT1( "recv_line: get zero. %s\n", strerror(errno) );
            break;
        }
        
        *p++ = c;
        total_len++;

        if( c == '\n' ) break;
        if( bufsiz < total_len ) break;
    }
    *p = 0;

    return total_len;
}


/***** Global functions *****************************************************/

/****************************************************************************/
/*! send n bytes.
 *
 *@param        sd      socket descriptor
 *@param        buf     pointer of send buffer
 *@param        len     message length
 *@param        flags   flags of send()
 *@retval       int     number of bytes sent, or -1 if an error.
 *@note
 *
 */
int sendn( int sd, const char *buf, int len, int flags )
{
    int left = len;
    int n;

    while( left > 0 ) {
        n = send( sd, buf, left, flags );
        if( n < 0 ) {
            if( errno == EINTR ) continue;
            DEBUGPRINT1( "sendn: get minus. %s\n", strerror(errno) );
            return n;
        }
        buf += n;
        left -= n;
    }

    return len;
}


/****************************************************************************/
/*! send ftp command
 *
 *@param        ftp     pointer of LIBOFTP.
 *@param        cmd     ftp command.
 *@retval       int     0 is no error, or -1 if an error.
 *@note
 *
 */
int ftp_send_command( LIBOFTP *ftp, const char *cmd )
{
    int ret;
    DEBUGPRINT1( "SENDC: %s", cmd );
    ret = sendn( ftp->socket, cmd, strlen( cmd ), 0 );
    if( ret < 0 ) {
        copy_strerror();
        return ret;
    }

    return 0;
}


/****************************************************************************/
/*! receive response
 *
 *@param        ftp     pointer of LIBOFTP.
 *@param        res_buf response buffer ( null ok )
 *@param        bufsiz  response buffer size.
 *@retval       int     reply code, or error code (minus value)
 *@note
 * set reply code to ftp attribute reply_code;
 */
int ftp_receive_response( LIBOFTP *ftp, char *res_buf, int bufsiz )
{
    char str1[256];
    int n;

    ftp->reply_code = 0;
    if( res_buf ) {
        *res_buf = 0;
    }

    /*
     * receive 1st line.
     */
    if( (n = recv_line( ftp->socket, str1, sizeof(str1), 0 )) < 0 ) {
        if( errno == EAGAIN ) {
            return LIBOFTP_ERROR_TIMEOUT;
        }
        copy_strerror();
        return LIBOFTP_ERROR_OS;
    }
    DEBUGPRINT1( "RESP1: %s", str1 );
    if( n < 3 ) {
        return LIBOFTP_ERROR_PROTOCOL;
    }
    ftp->reply_code = atoi( str1 );

    /*
     * if exist next line, receive all response.
     */
    if( str1[3] == '-' ) {
        while( 1 ) {
            if( (n = recv_line( ftp->socket, str1, sizeof(str1), 0 )) < 0 ) {
                if( errno == EAGAIN ) {
                    return LIBOFTP_ERROR_TIMEOUT;
                }
                copy_strerror();
                return LIBOFTP_ERROR_OS;
            }
            DEBUGPRINT1( "RESP2: %s", str1 );
            if( n < 3 ) {
                return LIBOFTP_ERROR_PROTOCOL;
            }

            if( atoi(str1) == ftp->reply_code && str1[3] == ' ' ) {
                break;
            }
        }
    }

    /*
     * copy a response strings to user buffer, if need
     */
    if( res_buf ) {
        strncpy( res_buf, str1, bufsiz );
        res_buf[bufsiz-1] = 0;
    }

    return ftp->reply_code;
}


/****************************************************************************/
/*! 送受信準備　アクティブモード
 *
 *@param        ftp     LIBOFTPへのポインタ。
 *@param        cmd     FTPコマンド (ex: RETR, STOR, APPE)
 *@param        fname   サーバ上のファイル名
 *@retval       int     ソケット, マイナス値ならエラーコード
 *@note
 アクティブモードで送受信の際の、以下の３ステートをサポートする。
 例) 受信時
       (port open) --> PORT --> RETR
 */
int ftp_getready_active( LIBOFTP *ftp, const char *cmd, const char *fname )
{
    int sock = 0;
    struct sockaddr_in saddr;
    int saddr_len;
    unsigned char *ip, *pt;
    char str1[256];
    int res;
    struct timeval timeout;
    fd_set rfds, wfds;

    /*
     * open data port.
     * (note)
     *  same command port ip and automatic random port.
     */
    sock = socket( PF_INET, SOCK_STREAM, IPPROTO_TCP );
    if( sock < 0 ) {
        DEBUGPRINT1( "getready_active: can't open socket. %s\n", strerror(errno) );
        goto ERROR_OS;
    }

    memset( &saddr, 0, sizeof( saddr ) );
    saddr_len = sizeof( saddr );
    if( getsockname( ftp->socket, (struct sockaddr *)&saddr, &saddr_len ) < 0 ) {
        DEBUGPRINT1( "getready_active: can't get control socket name. %s\n", strerror(errno) );
        goto ERROR_OS;
    }
    saddr.sin_port = htons( 0 );

    if( bind( sock, (struct sockaddr *)&saddr, sizeof( saddr ) ) < 0 ) {
        DEBUGPRINT1( "getready_active: can't bind socket. %s\n", strerror(errno) );
        goto ERROR_OS;
    }

    if( listen( sock, 1 ) < 0 ) {
        DEBUGPRINT1( "getready_active: can't listen socket. %s\n", strerror(errno) );
        goto ERROR_OS;
    }


    /*
     * make PORT command.
     */
    memset( &saddr, 0, sizeof( saddr ) );
    saddr_len = sizeof( saddr );
    if( getsockname( sock, (struct sockaddr *)&saddr, &saddr_len ) < 0 ) {
        DEBUGPRINT1( "getready_active: can't get data socket name. %s\n", strerror(errno) );
        goto ERROR_OS;
    }
    ip = (unsigned char*)&saddr.sin_addr.s_addr;
    pt = (unsigned char*)&saddr.sin_port;
    snprintf( str1, sizeof(str1), "PORT %d,%d,%d,%d,%d,%d\r\n", ip[0], ip[1], ip[2], ip[3], pt[0], pt[1] );

    /*
     * send PORT command and get status.
     */
    if( ftp_send_command( ftp, str1 ) < 0 ) {
        DEBUGPRINT1( "getready_active: %s command sending error.\n", "PORT" );
        close( sock );
        return LIBOFTP_ERROR_OS;
    }
    res = ftp_receive_response( ftp, ftp->error_message, sizeof(ftp->error_message) - 1 );
    if( res != 200 ) {                                  /* 200: Command okay. */
        DEBUGPRINT1( "getready_active: get PORT response code %d\n", res );
        close( sock );
        return LIBOFTP_ERROR_PROTOCOL;
    }
    
    /*
     * send ftp command.
     */
    if( fname ) {
        snprintf( str1, sizeof(str1), "%s %s\r\n", cmd, fname );
    } else {
        snprintf( str1, sizeof(str1), "%s\r\n", cmd );
    }
    if( ftp_send_command( ftp, str1 ) < 0 ) {
        DEBUGPRINT1( "getready_active: command sending error. %s", str1 );
        close( sock );
        return LIBOFTP_ERROR_OS;
    }

    /*
     * accept data connection with timeout.
     */
    timeout.tv_sec = ftp->timeout_sec;
    timeout.tv_usec = 0;

    do {
        FD_ZERO( &rfds );
        FD_ZERO( &wfds );
        FD_SET( sock, &rfds );
        FD_SET( sock, &wfds );
        
        res = select( sock+1, &rfds, &wfds, 0, &timeout );
        if( res == 0 ) {                /* timeout */
            DEBUGPRINT1( "getready_active: waiting connection timeout.%s\n", "" );
            close( sock );
            strncpy( ftp->error_message, "connection timeout.", sizeof( ftp->error_message )-1 );
            return LIBOFTP_ERROR_TIMEOUT;
        }
        if( res < 0 ) {
            if( errno == EINTR ) continue;
            DEBUGPRINT1( "getready_active: select error. %s\n", strerror(errno) );
            goto ERROR_OS;
        }

        if( FD_ISSET( sock, &rfds ) || FD_ISSET( sock, &wfds ) ) break;
    } while( 1 );

    res = accept( sock, (struct sockaddr *)&saddr, &saddr_len );
    close( sock );
    if( res < 0 ) {
        DEBUGPRINT1( "getready_active: socket accept error. %s\n", strerror(errno) );
        goto ERROR_OS;
    }
    sock = res;

    /*
     * get status.
     */
    res = ftp_receive_response( ftp, ftp->error_message, sizeof(ftp->error_message) - 1 );
    if( res != 150 ) {                                  /* 150: File status okay; about to open data connection. */
        DEBUGPRINT1( "getready_active: get STOR/RETR response code %d\n", res );
        close( sock );
        return LIBOFTP_ERROR_PROTOCOL;
    }

    return sock;

    
ERROR_OS:
    copy_strerror();
    if( sock > 0 ) {
        close( sock );
    }
    return LIBOFTP_ERROR_OS;
}


/****************************************************************************/
/*! 送受信準備　パッシブモード
 *
 *@param        ftp     LIBOFTPへのポインタ。
 *@param        cmd     FTPコマンド (ex: RETR, STOR, APPE)
 *@param        fname   サーバ上のファイル名
 *@retval       int     ソケット, マイナス値ならエラーコード
 *@note
 パッシブモードで送受信の際の、以下の３ステートをサポートする。
 例) 受信時
       PASV --> RETR --> (port open)
 */
int ftp_getready_pasv( LIBOFTP *ftp, const char *cmd, const char *fname )
{
    char str1[256];
    int res;
    char *p;
    int h1, h2, h3, h4, p1, p2;
    struct sockaddr_in saddr;
    int sock;
    struct timeval tval;

    /*
     * send "PASV" command and get status.
     */
    str1[255] = 0;
    snprintf( str1, sizeof(str1)-1, "PASV\r\n" );
    if( ftp_send_command( ftp, str1 ) < 0 ) {
        return LIBOFTP_ERROR_OS;
    }
    res = ftp_receive_response( ftp, str1, sizeof(str1) - 1 );
    if( res != 227 ) {                                  /* 227: Entering Passive Mode */
        DEBUGPRINT1( "getready_pasv: get ftp response code %d\n", res );
        strncpy( ftp->error_message, str1, sizeof( ftp->error_message ) - 1 );
        return LIBOFTP_ERROR_PROTOCOL;
    }

    /*
     * parse (h1,h2,h3,h4,p1,p2)
     */
    p = strchr( str1, '(' );
    if( p == NULL ) {
        DEBUGPRINT1( "getready_pasv: response parse error. %d", 1 );
        strncpy( ftp->error_message, "Illegal pasv response", sizeof(ftp->error_message) - 1 );
        return LIBOFTP_ERROR_PROTOCOL;
    }
    if( sscanf( p+1, "%d,%d,%d,%d,%d,%d", &h1, &h2, &h3, &h4, &p1, &p2 ) != 6 ) {
        DEBUGPRINT1( "getready_pasv: response parse error. %d", 2 );
        strncpy( ftp->error_message, "Illegal pasv response", sizeof(ftp->error_message) - 1 );
        return LIBOFTP_ERROR_PROTOCOL;
    }


    /*
     * send ftp command.
     */
    if( fname ) {
        snprintf( str1, sizeof(str1), "%s %s\r\n", cmd, fname );
    } else {
        snprintf( str1, sizeof(str1), "%s\r\n", cmd );
    }
    if( ftp_send_command( ftp, str1 ) < 0 ) {
        DEBUGPRINT1( "getready_pasv: command sending error. %s", str1 );
        return LIBOFTP_ERROR_OS;
    }

    /*
     * open data port.
     */
    sock = socket( PF_INET, SOCK_STREAM, IPPROTO_TCP );
    if( sock < 0 ) {
        DEBUGPRINT1( "getready_pasv: can't open socket. %s\n", strerror(errno) );
        copy_strerror();
        return LIBOFTP_ERROR_OS;
    }

    memset( &saddr, 0, sizeof( saddr ) );
    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = htonl( (((unsigned long)h1) << 24) | (h2 << 16) | (h3 << 8) | h4 );
    saddr.sin_port = htons( (p1 << 8) | p2 );

    if( connect( sock, (struct sockaddr *)&saddr, sizeof( saddr ) ) < 0 ) {
        DEBUGPRINT1( "getready_pasv: can't connect socket. %s\n", strerror(errno) );
        copy_strerror();
        close( sock );
        return LIBOFTP_ERROR_OS;
    }

    tval.tv_sec = ftp->timeout_sec;
    tval.tv_usec = 0;
    if( setsockopt( sock, SOL_SOCKET, SO_RCVTIMEO, &tval, sizeof(struct timeval) ) < 0 ) {
        DEBUGPRINT1( "setsockopt(SO_RCVTIMEO) failed. %s\n", strerror(errno) );
        copy_strerror();
        close( sock );
        return LIBOFTP_ERROR_OS;
    }
    
    /*
     * check response.
     */
    res = ftp_receive_response( ftp, ftp->error_message, sizeof(ftp->error_message) - 1 );
    if( res == 150 || res == 125 ) {
        return sock;
    } else {
        close( sock );
        return LIBOFTP_ERROR_PROTOCOL;
    }
}


/****************************************************************************/
/*! バッファへリスト取得
 *
 *@param        ftp     LIBOFTPへのポインタ。
 *@param        cmd     コマンド (RETR|LIST|NLST)
 *@param        fname   ファイル名または、グロブ。
 *@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_main( LIBOFTP *ftp, const char *cmd, 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, cmd, fname );
    } else {
        data_socket = ftp_getready_active( ftp, cmd, 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;
    }
}