Execute C program through a HTML on a http web server - embeded Linux

[alien-w]

Hi guys,

I would like to execute an already written C program that I am running on my embedded Linux, but from afar - through a HTML page.

I am running an embedded Linux on my FPGA prototype board with a MicroBlaze soft processor. On this Linux i am running a httpd web server - I can serve html web pages to the outside through Ethernet connection.
Now, I have a program written in C in this embedded Linux in /bin/gpio-test that does some stuff with my IO devices.
Now I would like to control these IO devices through HTML web page - so I would like to be able to run this gpio-test program from a html web page and possibly send the program some parameters.

Can you help?

Thanks a lot!

[GNU-Fan]

Look for CGI (common gateway interface).

[alien-w]

I did.

I put a simple hello.c in my CGI-BIN folder for embedded system, where I have access via HTTP:

#include <stdio.h>
int main(void) {
printf("Content-Type: text/plain;charset=us-ascii\n\n");
printf("Hello world\n\n");
return 0;
}

Then I did gcc -o hello.cgi hello.c
Then I built the embedded system (cross-compiled on my host machine - mb-linux-gcc) and transferred the image to the system.

When I run ./hello.cgi locally on the embedded system I get:
./hello.cgi: 1: Syntax error: "(" unexpected

So it doesn't even work locally.

[theNbomr]

Okay, so what is the nature of the embedded system? Are you sure you have the correct cross toolchain to build binaries for that architecture? Have you run cross-compiled code on the embedded system before?
--- rod.

[Rubberman]

Also, how did you transfer the file to the embedded system? If you used FTP, the .cgi extension may have been misinterpreted as a text file and it may have converted some of the embedded characters during the transfer.

[sixdrift]

Another piece of information that would help is what httpd server are you using. You need to ensure the CGI connection is configured correctly for the server.

[JohnGraham]

At work, we use haserl (haserl.sourceforge.net) running on lighttpd, which I don't really know how to use (I just compile it and make it available to more web-oriented people ) and I don't know how it compares to CGI, but I think it's basically like being able to put bash scripting in HTML, and the people who use it here seem to like it.

[sixdrift]

In relooking at the original error message in the OP, I think the problem is with the shell on the embedded system trying to run the hello.cgi as an interpreted script with some interpreter. There may be further HTTP server config needed as well.

Just for grins, can you drop the .cgi extension and does it work right on the target system?

[theNbomr]

In relooking at the original error message in the OP, I think the problem is with the shell on the embedded system trying to run the hello.cgi as an interpreted script with some interpreter. There may be further HTTP server config needed as well.

Just for grins, can you drop the .cgi extension and does it work right on the target system?

You could be right. My thought was that the error message looks like he tried to run the C source code in a shell. The #include first line looks like a comment, and the first thing to be syntactically wrong is the opening parenthesis, which is what the error message contains.
It looks like the OP is doing a hit & run, so I've quit losing sleep over this one.
--- rod.