# CGI with Awk on OpenBSD httpd

# CGI with Awk on OpenBSD httpd
-------------------------------

Last edited: $Date: 2020/01/04 20:27:46 $

Remember that for httpd OpenBSD chroots to /var/www.

To run an Awk CGI-script on OpenBSD httpd:

- set up configurations file(s)
- put your script in /var/www/cgi-bin/
- populatie the chroot (meaning: /var/www/) with the needed
binaries and libraries.

## Prepare /etc/httpd

Below follows some content for /etc/httpd, with some lines for SSL
certificate through the acme-client. For security, we included some
simple basic authentication with htpasswd.

ext_ip = "10.0.0.4"

server "www.example.com" {
listen on $ext_ip port 80
listen on $ext_ip tls port 443
root "/htdocs/www.example.com/"
directory { index "index.html" }
location "/.well-known/acme-challenge/*" {
root "/acme"
request strip 2
}
location "/cgi-bin/*" {
authenticate MySecretRealm with "/data/htpasswd"
fastcgi
root "/"
}
tls {
certificate "/etc/ssl/www.example.com.crt"
key "/etc/ssl/private/www.example.com.key"
}
}

Check the file for syntax errors with: httpd -n

Off course you can start with http only. leaving out the port 443
and the tls-part.

## Setup htpasswd

mkdir /var/www/data
htpasswd /var/www/data/htpasswd UserName
chown -R :www /var/www/data

## Create a CGI-script

Here is a nice example script:

#!/bin/awk -f

BEGIN {
printf("Status: 200 OK\n");
printf("Content-type: text/plain\n\n");

for ( key in ENVIRON ) {
print key " : " ENVIRON[key];
}
}

Put this script in /var/www/cgi-bin/test.awk

## Populate the chroot

Create a subdirectory for bin and lib files Use ldd to determine.
which lib files are needed.

mkdir -p /var/www/usr/{bin,lib,libexec}
cd /var/www/usr/bin/
cp /usr/bin/awk .
ldd /var/www/usr/bin/awk

And copy the lib files

cp /usr/lib/libm.so* /var/www/usr/lib/
cp /usr/lib/libc.so* /var/www/usr/lib/
cp /usr/libexec/ld.so /var/www/usr/libexec/ld.so

## Enable and start slowcgi and httpd

rcctl enable slowcgi
rcctl enable httpd
rcctl start slowcgi
rcctl start httpd

Now, point your browser to:

- http://www.example.com/cgi-bin/test.awk
- http://www.example.com/cgi-bin/test.awk?abc=123

and enjoy :)

When in trouble, look for error messages in your logfiles in
/var/www/logs/.

Another possibility is to run /usr/sbin/httpd -dvvv and see if this
turns up some helpful messages.

$Id: cgi_with_awk_on_openbsd_httpd.txt,v 1.4 2020/01/04 20:27:46 matto Exp matto $