c socket file transfer, server does not open existing file - c

Question

I am writing simple client-server program. Essentially I am following example from "Linux Network Programming" book. This is simple TCP server
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <netdb.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <string.h>
#define SERVERPORT 8888
#define MAXBUF 1024
int main(int argc, char* argv[])
{
int socket1, socket2;
int addrlen;
struct sockaddr_in fServer, fClient;
int status;
socket1=socket(AF_INET, SOCK_STREAM, 0);
if(socket1==-1)
{
printf("Could not create the socket\n");
exit(1);
}
fServer.sin_family=AF_INET;
fServer.sin_addr.s_addr=INADDR_ANY;
fServer.sin_port= htons(SERVERPORT);
status=bind(socket1, (struct sockaddr*) &fServer,
sizeof(fServer));
if(status==-1)
{
printf("could not bind the socket\n");
exit(1);
}
else printf("socket is created\n");
status=listen(socket1, 5);
if(status==-1)
{
printf("could not listen socket\n");
exit(1);
}
else printf("socket is waiting for connection\n");
for(;;)
{
int fd;
int i, readCounter, writeCounter;
char* bufptr;
char buf[MAXBUF];
char filename[MAXBUF];
addrlen=sizeof(fClient);
socket2=accept(socket1, (struct sockaddr*) &fClient, &addrlen);
if(socket2==-1)
{
printf("could not accept connection\n");
exit(1);
}
else printf("connection established, waiting for the file name\n");
i=0;
if((readCounter=read(socket2, filename, MAXBUF))>0)
i+=readCounter;
filename[i+1]='\0';
printf("reading from the file\n");
fd=open(filename, O_RDONLY);
if(fd==-1)
{
printf("could not open the file\n");
perror(" error is detected: ");
close(socket2);
continue;
}
else printf("file name is recieved, started copying\n");
readCounter=0;
while((readCounter=read(fd, buf, MAXBUF))>0)
{
writeCounter=0;
bufptr=buf;
while(writeCounter<readCounter)
{
readCounter-=writeCounter;
bufptr+=writeCounter;
writeCounter=write(socket2, bufptr, readCounter);
if(writeCounter==-1)
{
printf("could not write the file to client\n");
close(socket2);
continue;
}
}
}
close(fd);
close(socket2);
}
close(socket1);
return 0;
}
This code is for client.
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#define SERVERPORT 8888
#define MAXBUF 1024
int main(int argc, char* argv[])
{
int sockd;
int counter;
int fd;
struct sockaddr_in fServer;
char buf[MAXBUF];
int status;
if(argc<3)
{
printf("Incorrect data provided\n");
exit(1);
}
sockd=socket(AF_INET, SOCK_STREAM,0);
if(sockd==-1)
{
printf("could not create socket\n");
exit(1);
}
fServer.sin_family=AF_INET;
fServer.sin_addr.s_addr=inet_addr(argv[1]);
fServer.sin_port=htons(SERVERPORT);
status=connect(sockd, (struct sockaddr*)&fServer,
sizeof(fServer));
if(status==-1)
{
printf("could not connect to server\n");
exit(1);
}
status=write(sockd, argv[2], strlen(argv[2]+1));
if(status==-1)
{
printf("could not send file name to server\n");
exit(1);
}
shutdown(sockd, SHUT_WR);
fd=open(argv[2], O_WRONLY| O_CREAT| O_APPEND);
if(fd==-1)
{
printf("could not open destination file\n");
exit(1);
}
while((counter=read(sockd, buf, MAXBUF))>0)
{
write(fd, buf, counter);
}
if(counter==-1)
{
printf("file transfer is complete\n");
exit(1);
}
printf("file transfer is complete\n");
close(sockd);
return 0;
}
I pass file name from the same directory as server. I pass filename as agrc[2] parameter. Server oputput however is the following
socket is created
socket is waiting for connection
connection established, waiting for the file name
reading from the file
could not open the file
error is detected: : No such file or directory
connection established, waiting for the file name
reading from the file
could not open the file
error is detected: : No such file or directory
I entered the filename on my first attempt, then I enterd full path but still recieving the same message. So what is the problem? thanks in advance

Answer 1

Client:
status=write(sockd, argv[2], strlen(argv[2]+1));
strlen(argv[2]+1) should be strlen(argv[2])+1 if you want to include the \0.also: you do not close your fd. close(sockd); should be close(fd);
Server:
filename[i+1]='\0'; should be filename[i]='\0'; if you are not sure you received the \0.
if you are sending 1 char, for example 'a', i would be 1 and your array would look like
filename[0] = 'a'
filename[i] = undefined
filename[i+1] = '\0'

Answer 2

Unrelated to your problem, but on the server side you should advance bufptr after write(), not before.
Also: TCP is a stream protocol; there is no guarantee that a write() on one end of a connection will be completely read by a single recv() on the other end.