Here's the final code for server.c and client.c. In case anyone needs an example of how to transfer a file. I know I could have used one. Would have saved me lots of hours of toil. I fixed some other things so don't use any original code, otherwise you might get double the txt in your new downloaded file as I was getting and had to debug to fix it. Also this has only been run on linux, not sure how it will hold up on windows. The green code is what does the talking/file transfering the rest of the previous code above that in both client and server is just setting up the socket.
Server.c
Code:
/* server.c - code for example server program that uses TCP */
#ifndef unix
#define WIN32
#include <windows.h>
#include <winsock.h>
#else
#define closesocket close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <netdb.h>
#endif
#include <stdio.h>
#include <string.h>
#define PROTOPORT 5193 /* default protocol port number */
#define QLEN 6 /* size of request queue */
int visits = 0; /* counts client connections */
/*------------------------------------------------------------------------
* * Program: server
* * Syntax: server [ port ]
* *
* * port - protocol port number to use
* *
* * Note: The port argument is optional. If no port is specified,
* * the server uses the default given by PROTOPORT.
* *
* *------------------------------------------------------------------------
* */
main(argc, argv)
int argc;
char *argv[];
{
struct hostent *ptrh; /* pointer to a host table entry */
struct protoent *ptrp; /* pointer to a protocol table entry */
struct sockaddr_in sad; /* structure to hold server.s address */
struct sockaddr_in cad; /* structure to hold client.s address */
int sd, sd2; /* socket descriptors */
int port; /* protocol port number */
int alen; /* length of address */
char buf_recv[1000],buf_send[1000]; /* buffer for string the server sends */
char file_buffer[10000],f_buffer[1000];
int n;
FILE *fp;
#ifdef WIN32
WSADATA wsaData;
WSAStartup(0x0101, &wsaData);
#endif
memset((char *)&sad,0,sizeof(sad)); /* clear sockaddr structure */
sad.sin_family = AF_INET; /* set family to Internet */
sad.sin_addr.s_addr = INADDR_ANY; /* set the local IP address */
/* Check command-line argument for protocol port and extract */
/* port number if one is specified. Otherwise, use the default */
/* port value given by constant PROTOPORT */
if (argc > 1) { /* if argument specified */
port = atoi(argv[1]); /* convert argument to binary */
} else {
port = PROTOPORT; /* use default port number */
}
if (port > 0) /* test for illegal value */
sad.sin_port = htons((u_short)port);
else { /* print error message and exit */
fprintf(stderr,"bad port number %s\n",argv[1]);
exit(1);
}
/* Map TCP transport protocol name to protocol number */
if ( ((int)(ptrp = getprotobyname("tcp"))) == 0) {
fprintf(stderr, "cannot map \"tcp\" to protocol number");
exit(1);
}
/* Create a socket */
sd = socket(PF_INET, SOCK_STREAM, ptrp->p_proto);
if (sd < 0) {
fprintf(stderr, "socket creation failed\n");
exit(1);
}
/* Bind a local address to the socket */
if (bind(sd, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
fprintf(stderr,"bind failed\n");
exit(1);
}
/* Specify size of request queue */
if (listen(sd, QLEN) < 0) {
fprintf(stderr,"listen failed\n");
exit(1);
}
/* Main server loop - accept and handle requests */
//while (1) {
alen = sizeof(cad);
if ( (sd2=accept(sd, (struct sockaddr *)&cad, &alen)) < 0) {
fprintf(stderr, "accept failed\n");
exit(1);
}
sprintf(buf_send,"Please enter the file name: ");
send(sd2,buf_send,strlen(buf_send),0);
n=recv(sd2,buf_recv,1000,0);
buf_recv[n]='\0';
printf("%s\n",buf_recv);
fflush(stdout);
if((fp = fopen(buf_recv,"r"))==NULL)
{
sprintf(buf_send,"File could not be found!!!");
exit(0);
}
else
sprintf(buf_send,"File found!!!\n");
send(sd2,buf_send,strlen(buf_send),0);
n=recv(sd2,buf_recv,1000,0);
printf("%s",buf_recv);
fflush(stdout);
while(!feof(fp))
{
fgets(f_buffer,1000,fp);
if (feof(fp))
break;
strcat(file_buffer,f_buffer);
}
fclose(fp);
send(sd2,file_buffer,strlen(file_buffer),0);
closesocket(sd2);
//}
//closesocket(sd);
exit(0);
}
client.c
Code:
/* client.c - code for example client program that uses TCP */
#ifndef unix
#define WIN32
#include <windows.h>
#include <winsock.h>
#else
#define closesocket close
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif
#include <stdio.h>
#include <string.h>
#define PROTOPORT 5193 /* default protocol port number */
extern int errno;
char localhost[] = "localhost"; /* default host name */
/*------------------------------------------------------------------------
* * Program: client
* *
* * Purpose: allocate a socket, connect to a server
* * Syntax: client [ host [port] ]
* *
* * host - name of a computer on which server is executing
* * port - protocol port number server is using
* *
* * Note: Both arguments are optional. If no host name is specified,
* * the client uses "localhost"; if no protocol port is
* * specified, the client uses the default given by PROTOPORT.
* *
* *------------------------------------------------------------------------
* */
main(argc, argv)
int argc;
char *argv[];
{
struct hostent *ptrh; /* pointer to a host table entry */
struct protoent *ptrp; /* pointer to a protocol table entry */
struct sockaddr_in sad; /* structure to hold an IP address */
int sd; /* socket descriptor */
int port; /* protocol port number */
char *host; /* pointer to host name */
int n; /* number of characters read */
char buf_recv[1000],buf_send[100]; /* buffer for data from the server */
char *filename;
char file_buffer[10000];
FILE *fp;
#ifdef WIN32
WSADATA wsaData;
WSAStartup(0x0101, &wsaData);
#endif
memset((char *)&sad,0,sizeof(sad)); /* clear sockaddr structure */
sad.sin_family = AF_INET; /* set family to Internet */
/* Check command-line argument for protocol port and extract */
/* port number if one is specified. Otherwise, use the default */
/* port value given by constant PROTOPORT */
if (argc > 2) { /* if protocol port specified */
port = atoi(argv[2]); /* convert to binary */
} else {
port = PROTOPORT; /* use default port number */
}
if (port > 0) /* test for legal value */
sad.sin_port = htons((u_short)port);
else { /* print error message and exit */
fprintf(stderr,"bad port number %s\n",argv[2]);
exit(1);
}
/* Check host argument and assign host name. */
if (argc > 1) {
host = argv[1]; /* if host argument specified */
} else {
host = localhost;
}
/* Convert host name to equivalent IP address and copy to sad. */
ptrh = gethostbyname(host);
if ( ((char *)ptrh) == NULL ) {
fprintf(stderr,"invalid host: %s\n", host);
exit(1);
}
memcpy(&sad.sin_addr, ptrh->h_addr, ptrh->h_length);
/* Map TCP transport protocol name to protocol number. */
if ( ((int)(ptrp = getprotobyname("tcp"))) == 0) {
fprintf(stderr, "cannot map \"tcp\" to protocol number");
exit(1);
}
/* Create a socket. */
sd = socket(PF_INET, SOCK_STREAM, ptrp->p_proto);
if (sd < 0) {
fprintf(stderr, "socket creation failed\n");
exit(1);
}
/* Connect the socket to the specified server. */
if (connect(sd, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
fprintf(stderr,"connect failed\n");
exit(1);
}
n = recv(sd, buf_recv, sizeof(buf_recv), 0);
buf_recv[n]='\0';
printf("%s",buf_recv);
scanf("%s",buf_send);
send(sd,buf_send,strlen(buf_send),0);
n = recv(sd, buf_recv, sizeof(buf_recv), 0);
buf_recv[n]='\0';
printf("%s",buf_recv);
fflush(stdout);
sprintf(buf_send,"Client acknowledges, Sending file now.\n");
send(sd,buf_send, strlen(buf_send),0);
n=recv(sd, file_buffer, sizeof(file_buffer), 0);
file_buffer[n]='\0';
//printf("%s %d\n",file_buffer,n);
fflush(stdout);
fp = fopen("DOWNLOADED.TXT","w");
fputs(file_buffer,fp);
fclose(fp);
closesocket(sd);
/* Terminate the client program gracefully. */
exit(0);
}