server_ftp.c

/* 
 *	Program:        server_ftp.c 
 *	Author:         Tianyu Song
 *	TUT_stuNumber 	20126169 
 *	Date:           Sept 2011 
 *	
 *	Objective:      Show how to use a tcp socket  
 *	on a server program running on 
 *	Sun/Solaris ; after the connection, *                       this program receives a client message 
 *	and sends back an acknowledge each time. 
 *	
 *	Options to compile and link on Solaris: 
 *	===>    gcc server_ftp.c -lsocket -o server_ftp 
 *	Options to compile and link on Linux: 
 *	===>    gcc server_ftp.c -o server_ftp 
 *	
 *	Execution:  server_base   5161  
 *	
 *	Files to include 
 */ 

#include <errno.h> 
#include <string.h> 
#include <sys/types.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <netdb.h> 
#include <sys/time.h>  
#include <stdio.h> 

/* 
 *	The following functions are used in this program 
 *	
 *	socket, bind, getsockname, listen,  
 *	accept, read, write, close. 
 */ 

#define ACK "ACK" 
#define NAK "NAK" 

FILE *fptr ;  struct sockaddr_in server1;  /* structure used to assign a name 
                                              to a socket sccording internet format*/ 
int rval;                                      /* status code for read */  
int writeNum = 0 ;                  /*Time to transfer file*/  
int sizeNum = 0 ;  
int sock1, msgsock;              /* socket descriptors */                 
int addrlen, length;               /* Linux: #octets in the structure sockadr_in */     
char buf[1000];                         /* buffer for transmission */ 
char remote_filename[20] ; 

int getSocketBase(int argc , char *argv[]){ 

    /* 
     *	1. Validation of the 2 parameters read on the command line 
     */        
    if (argc != 2)        
    {   	 	 	
        printf("Call the program this way : server_base port_number\n"); 
        return 1; 
    } 
    /* 
     *	2. Socket creation parameters:           
     *	- AF_INET is the internet format  *               - SOCK_STREAM specifies a TCP type socket 
     *	- 0 specifies to use the default protocol. 
     */        
    sock1 = socket(AF_INET, SOCK_STREAM, 0);     
    if (sock1 < 0)        
    {                 
        perror("Error in creating a TCP socket ");             
        return 1; 
    }  

    /* 
     *	3. Specify the local part of the address : 
     *	1)the local port number in network format and 
     *	2)the local IP address.  INADDR_ANY is used on a server 
     *	because many ip addresses may be used on the same machine. 
     *	
     *	Client connections will be redirected to other temporary sockets. 
     *	Use your own port number. 
     */ 
    server1.sin_family = AF_INET;           /* internet format       
    */ 
    server1.sin_addr.s_addr = INADDR_ANY;   
    /* under-specified address    */    
    server1.sin_port = htons(atoi(argv[1])); 

    return 0 ; 
} 
int getBind(){ 

    if (bind(sock1, (struct sockaddr *) &server1, sizeof(server1)) < 0) 
    {               
        return 1; 
    }else   	 	 
        return 0;
} 
int startListening(){ 

    /* 
     *	4. Simple validation: find the name associated to this socket 
     *	and print its port number 
     */        
    length = sizeof(server1);      
    if (getsockname(sock1, (struct sockaddr *)&server1, &length) < 0 ) 
    {          
        return 1; 
    } 
    printf("The port number used by the tcp socket is #%d\n", ntohs(server1.sin_port)); 


    /* 
     *	5. Fix the maximum number of clients waiting connection and          leave the server in passive mode 
     */              
    listen(sock1, 5);    
    puts("server ready for connection");   	
    return 0 ; 
} 
void getClientMessage(){ 

    /* 
     *	6. Waiting for a client TCP connection 
     *	
     *	The second and third parameters are useless. *       A new temporary socket (msgsock) is created  
     *	for each client connection (msgsock). 
     */ 
    do  
    { 

        msgsock = accept(sock1, (struct sockaddr *) 0, NULL);   	
        puts("\n===================  Start  ===================\n") ;   	
        puts("Client connection");      
        if (msgsock == -1 ) perror("accept");   
        else do  
        { 

            /*       7. Client message is read in a 1K octets buffer. rval returns 
             *	the number of octets received. 
             */ 
            writeNum ++ ;   	 	
            if(writeNum == 1) 
            { 
                rval = read(msgsock, remote_filename, 800);   	 	 	
                remote_filename[rval] = '\0' ;   	 	 	 
                printf("Transfer File =====>%s\n",remote_filename) ;   	 	 
                if((fptr = fopen(remote_filename,"a")) == NULL) 
                { 
                    perror("error opening this file"); 
                } 
            } 
            rval = read(msgsock, buf, 800); 
            if (rval <= 0)             { 
                printf("End of client connection\t\tBy: 20126169 Tianyu Song\n\n");  
                puts("\n===================  Done  ===================\n") ; 
                close(msgsock) ; 
                fclose(fptr) ;   
                writeNum = 0 ;   	 
                sizeNum = 0 ; 
            } 	 
            else /* Printing of message and transmission of the acknowledge */ 
            { 
                buf[rval]='\0';     /* insert the end of character string*/ 
                fputs(buf,fptr) ;   	 	 	 	
                sizeNum+=strlen(buf) ; 
            } 
        }  while(rval > 0);   /* read until EOF data available */ 

    } while(1);          /* my server never stops */ 
} 
int main(int argc,char *argv[]) 

{ 
    if( getSocketBase(argc,argv)) 
    { 
        perror("Error in init Socket\n") ; 
        return 1; 
    } 
    if( getBind()) 
    { 
        perror(" The function bind did not work properly\n"); 
        return 1; 
    } 
    if( startListening()) 
    { 
        perror("Error in getsockname()\n"); 
        return 1; 
    } 
    getClientMessage();   	
    close(sock1);      
    return 0; 
}    
/* end of server program  */