To allow REC to communicate with a web browser, a CGI script is required to act as a proxy server to keep the session alive. The required setup is shown in the following figure:
In this setup, the web browser sends a request to the HTTP server. The HTTP server starts the CGI script, which extracts the command from the request, passes the command to the REC process, receives the HTML page generated by REC, adds some additional information and passes it back to the browser, which renders the page.
This approach requires that the user be able to run CGI scripts on the server system. This is not always possible, or it may require some assistance from your system administrator.
If you are using a Linux system, you can mimic the setup I use on my system. First of all, you must run the HTTP server, which is invoked with the 'httpd' command (you probably must be root to run this command).
The next step is to setup the CGI script. I wrote my own CGI program using one of the publicly available CGI libraries. You can download this program and compile it on your system by typing make. Once you have the cgirec executable, you must make it available to the HTTP server. On my Linux system, the server looks in the /home/cg/cgi-bin/ for the cgirec executable. If you have a different setup, you can created a symbolic link to the location where you compiled the executable. For example:
ln -s /home/cg/cgi-bin/cgirec /var/lib/httpd/cgi-bin/cgirec
Then, you must write a configuration file for cgirec.
This configuration file will tell cgirec where to
find the executable to decompile. Again, you can create a symbolic
link to make the configuration file visible from cgirec.
You can look at the file /tmp/proxy.trace for helpful
trace messages. A configuration file looks like this:
dir=/home/cg/recserv/
cpu=i386,ex386
cpu=ppc,exppc
cpu=mc68k,ex68k
The dir= line identifies the root directory containing
the files to be decompiled.
The cpu= lines identify different sessions.
The first word is the argument passed from the browser to cgirec.
The argument is used to select the name of the directory (the word after
the comma ',' sign) that contains the
program to decompile. cgirec will then change to that
directory (for example /home/cg/recserv/ex386) and start
a decompile session by executing the command
rec +html example
This means that the program to decompile must be called example
and that an executable called rec must be present in that
directory. Of course you can use symbolic links to point to the
location where the real executables reside.
Of course you are free to change the sources of cgirec.c to adapt it to your particular environment (a port to Windows 95/NT would be particularly appreciated. Any volunteer :-)
Multiple sessions can be executed in the same directory. cgirec maintains different communication channels to each session. A session is automatically terminated if the server has not received a command in the last 20 minutes.