Question on returning stdout from a server

verbena1 · 04-29-2005, 12:42 PM

I need some C/Unix networking help,

I'm working on a assignment in a unix environment that has two parts.
Part one implement a simple "shell" that parses a command and its arguments and then executes it, or if a pipe character is used ("|") parse the left side, parse the right side, and then manually pipe (using close() and dup()) and return this to a command line of my making (in my case my prompt is myShell

I have that done but now I need to implement it using networking. I have a client and a server and my setup is that the client connects to the server and the client prints out the prompt "myShell: " I can send a command and it works on the server end but I would like to know how to send the servers output of the command back to the client. I've looked around the internet and through my books (Richard Stevens Unix Networking book) and I can't find a way to do this unless I'm just missing something. I thought about maybe using dup() to make a copy of the input-send to the server-run my parse and execute functions-copy the output and send to to the client but I don't know how to do this. If I can send out this output is there a way to send my "myShell:" prompt directly from the server and save my client the trouble?

Any help would be appreciated

**Salem** · 04-29-2005, 12:48 PM

I imagine you dup() using socket descriptors instead of using the descriptors created by say pipe()

verbena1 · 04-29-2005, 12:59 PM

I'm not sure on the syntax though,

I know that in client its called sockfd, and in server newsockfd.
and this is where my server executes code after a connection:

Code:

for (;;) {

		/* accept a connection */

		if ( (newsockfd = accept(sockfd, NULL, NULL)) == -1) {

			perror("accept call failed");

			continue;

		}



		/* spawn a child to deal with the connection */

		if (fork() == 0) {

			while (recv(newsockfd, buf, MAXLINE, 0) > 0) {

				parse(buf, args1, args2);

				execute(args1, args2);

				send(newsockfd, buf, MAXLINE, 0);

			}

			/* when client is no longer sending information

			the socket can be closed and the child process

			terminated */

			close(newsockfd);

			exit (0);

		}

Do i dup() the stdout like i would for a pipe?
close(1);

dup(p[1]);

close(p[0]);
If so what am I assigning it too to send it back to the client?

04-29-2005, 12:42 PM	#1
verbena1 Registered User Join Date: Apr 2005 Posts: 2	Question on returning stdout from a server I need some C/Unix networking help, I'm working on a assignment in a unix environment that has two parts. Part one implement a simple "shell" that parses a command and its arguments and then executes it, or if a pipe character is used ("\|") parse the left side, parse the right side, and then manually pipe (using close() and dup()) and return this to a command line of my making (in my case my prompt is myShell I have that done but now I need to implement it using networking. I have a client and a server and my setup is that the client connects to the server and the client prints out the prompt "myShell: " I can send a command and it works on the server end but I would like to know how to send the servers output of the command back to the client. I've looked around the internet and through my books (Richard Stevens Unix Networking book) and I can't find a way to do this unless I'm just missing something. I thought about maybe using dup() to make a copy of the input-send to the server-run my parse and execute functions-copy the output and send to to the client but I don't know how to do this. If I can send out this output is there a way to send my "myShell:" prompt directly from the server and save my client the trouble? Any help would be appreciated
verbena1 is offline

04-29-2005, 12:48 PM	#2
Salem and the hat of Jobseeking Join Date: Aug 2001 Location: The edge of the known universe Posts: 21,647	I imagine you dup() using socket descriptors instead of using the descriptors created by say pipe() __________________ If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
Salem is offline

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Where's the EPIPE signal?	marc.andrysco	Networking/Device Communication	0	12-23-2006 08:04 PM
winsock server question?	kocho	Windows Programming	2	02-02-2006 01:52 PM
char* returning question	Devil Panther	C Programming	19	08-29-2005 12:50 PM
SWEBS Web Server	nickname_changed	A Brief History of Cprogramming.com	6	09-22-2003 02:46 AM
a question on server stuff	DavidP	A Brief History of Cprogramming.com	9	10-05-2001 02:54 PM