Provided by: mini-httpd_1.30-2build1_amd64 
NAME
mini_httpd - small HTTP server
SYNOPSIS
mini_httpd [-C configfile] [-p port] [-d dir] [-dd data_dir] [-c cgipat] [-u user] [-h
hostname] [-r] [-v] [-l logfile] [-i pidfile] [-T charset] [-P P3P] [-M maxage] [-S] [-E
certfile] [-Y cipher] [-D] [-V]
DESCRIPTION
mini_httpd is a small HTTP server. Its performance is not great, but for low or medium
traffic sites it's quite adequate. It implements all the basic features of an HTTP
server, including:
* GET, HEAD, and POST methods.
* CGI.
* Basic authentication.
* Security against ".." filename snooping.
* The common MIME types.
* Trailing-slash redirection.
* index.html, index.htm, index.cgi
* Directory listings.
* Multihoming / virtual hosting.
* Standard logging.
* Custom error pages.
It can also be configured to do SSL/HTTPS.
mini_httpd was written for a couple reasons. One, as an experiment to see just how slow
an old-fashioned forking web server would be with today's operating systems. The answer
is, surprisingly, not that slow - on FreeBSD 3.2, mini_httpd benchmarks at about 90% the
speed of Apache. The other main reason for writing mini_httpd was to get a simple
platform for experimenting with new web server technology, for instance SSL.
OPTIONS
-C Specifies a config-file to read. All options can be set either by command-line
flags or in the config file. See below for details.
-p Specifies an alternate port number to listen on. The default is 80. The config-
file option name for this flag is "port".
-d Specifies a directory to chdir() to at startup. This is merely a convenience - you
could just as easily do a cd in the shell script that invokes the program. The
config-file option name for this flag is "dir".
-dd Specifies a directory to chdir() to after chrooting. If you're not chrooting, you
might as well do a single chdir() with the -d flag. If you are chrooting, this
lets you put the web files in a subdirectory of the chroot tree, instead of in the
top level mixed in with the chroot files. The config-file option name for this
flag is "data_dir".
-c Specifies a wildcard pattern for CGI programs, for instance "**.cgi" or "cgi-
bin/*". The default is no CGI. The config-file option name for this flag is
"cgipat".
-u Specifies what user to switch to after initialization when started as root. The
default is "nobody". The config-file option name for this flag is "user".
-h Specifies a hostname to bind to, for multihoming. The default is to bind to all
hostnames supported on the local machine. The config-file option name for this
flag is "host".
-r Do a chroot() at initialization time, restricting file access to the program's
current directory. See below for details. The config-file option names for this
flag are "chroot" and "nochroot".
-v Do virtual hosting. See below for details. The config-file option name for this
flag is "vhost".
-l Specifies a log file name. The default is no logging. The config-file option name
for this flag is "logfile".
-i Specifies a file to write the process-id to. If no file is specified, no process-
id is written. You can use this file to send signals to mini_httpd. The config-
file option name for this flag is "pidfile".
-T Specifies the character set to use with text MIME types. The default is "UTF-8".
The config-file option name for this flag is "charset".
-P Specifies a P3P server privacy header to be returned with all responses. See
http://www.w3.org/P3P/ for details. Mini_httpd doesn't do anything at all with the
string except put it in the P3P: response header. The config-file option name for
this flag is "p3p".
-M Specifies the number of seconds to be used in a "Cache-Control: max-age" header to
be returned with all responses. An equivalent "Expires" header is also generated.
The default is no Cache-Control or Expires headers, which is just fine for most
sites. The config-file option name for this flag is "maxage".
-S If mini_httpd is configured to do SSL/HTTPS, then the -S flag is available to
enable this feature. The config-file option name for this flag is "ssl".
-E If mini_httpd is configured to do SSL/HTTPS, then you can specify a server
certificate with this flag. You can make a certificate with the command "make
cert". The default is "mini_httpd.pem" (in the directory where you start
mini_httpd). The config-file option name for this flag is "certfile".
-Y If mini_httpd is configured to do SSL/HTTPS, then you can specify a cipher set with
this flag. Examples of cipher sets: "RC4-MD5", "DES-CBC3-SHA", "AES256-SHA". The
default is to let each browser negotiate ciphers separately, and unless you know
what you're doing it's best to let them do so. The config-file option name for
this flag is "cipher".
-D This was originally just a debugging flag, however it's worth mentioning because
one of the things it does is prevent mini_httpd from making itself a background
daemon. Instead it runs in the foreground like a regular program. This is
necessary when you want to run mini_httpd wrapped in a little shell script that
restarts it if it exits. The config-file option name for this flag is "debug".
-V Shows mini_httpd's version and then exits.
CGI
mini_httpd supports the CGI 1.1 spec.
In order for a CGI program to be run, its name must match the pattern you specify with the
-c flag This is a simple shell-style filename pattern. You can use * to match any string
not including a slash, or ** to match any string including slashes, or ? to match any
single character. You can also use multiple such patterns separated by |. The patterns
get checked against the filename part of the incoming URL. Don't forget to quote any
wildcard characters so that the shell doesn't mess with them.
BASIC AUTHENTICATION
Basic Authentication uses a password file called ".htpasswd", in the directory to be
protected. This file is formatted as the familiar colon-separated username/encrypted-
password pair, records delimited by newlines. The protection does not carry over to
subdirectories. The utility program htpasswd(1) is included to help create and modify
.htpasswd files.
CHROOT
chroot() is a system call that restricts the program's view of the filesystem to the
current directory and directories below it. It becomes impossible for remote users to
access any file outside of the initial directory. The restriction is inherited by child
processes, so CGI programs get it too. This is a very strong security measure, and is
recommended. The only downside is that only root can call chroot(), so this means the
program must be started as root. However, the last thing it does during initialization is
to give up root access by becoming another user, so this is safe.
Note that with some other web servers, such as NCSA httpd, setting up a directory tree for
use with chroot() is complicated, involving creating a bunch of special directories and
copying in various files. With mini_httpd it's a lot easier, all you have to do is make
sure any shells, utilities, and config files used by your CGI programs and scripts are
available. If you have CGI disabled, or if you make a policy that all CGI programs must
be written in a compiled language such as C and statically linked, then you probably don't
have to do any setup at all.
However, one thing you should do is tell syslogd about the chroot tree, so that mini_httpd
can still generate syslog messages. Check your system's syslodg man page for how to do
this. In FreeBSD you would put something like this in /etc/rc.conf:
syslogd_flags="-l /usr/local/www/data/dev/log"
Substitute in your own chroot tree's pathname, of course. Don't worry about creating the
log socket, syslogd wants to do that itself. (You may need to create the dev directory.)
In Linux the flag is -a instead of -l, and there may be other differences.
MULTIHOMING
Multihoming means using one machine to serve multiple hostnames. For instance, if you're
an internet provider and you want to let all of your customers have customized web
addresses, you might have www.joe.acme.com, www.jane.acme.com, and your own www.acme.com,
all running on the same physical hardware. This feature is also known as "virtual hosts".
There are three steps to setting this up.
One, make DNS entries for all of the hostnames. The current way to do this, allowed by
HTTP/1.1, is to use CNAME aliases, like so:
www.acme.com IN A 192.100.66.1
www.joe.acme.com IN CNAME www.acme.com
www.jane.acme.com IN CNAME www.acme.com
However, this is incompatible with older HTTP/1.0 browsers. If you want to stay
compatible, there's a different way - use A records instead, each with a different IP
address, like so:
www.acme.com IN A 192.100.66.1
www.joe.acme.com IN A 192.100.66.200
www.jane.acme.com IN A 192.100.66.201
This is bad because it uses extra IP addresses, a somewhat scarce resource. But if you
want people with older browsers to be able to visit your sites, you still have to do it
this way.
Step two. If you're using the modern CNAME method of multihoming, then you can skip this
step. Otherwise, using the older multiple-IP-address method you must set up IP aliases or
multiple interfaces for the extra addresses. You can use ifconfig(8)'s alias command to
tell the machine to answer to all of the different IP addresses. Example:
ifconfig le0 www.acme.com
ifconfig le0 www.joe.acme.com alias
ifconfig le0 www.jane.acme.com alias
If your OS's version of ifconfig doesn't have an alias command, you're probably out of
luck.
Third and last, you must set up mini_httpd to handle the multiple hosts. The easiest way
is with the -v flag. This works with either CNAME multihosting or multiple-IP
multihosting. What it does is send each incoming request to a subdirectory based on the
hostname it's intended for. All you have to do in order to set things up is to create
those subdirectories in the directory where mini_httpd will run. With the example above,
you'd do like so:
mkdir www.acme.com www.joe.acme.com www.jane.acme.com
If you're using old-style multiple-IP multihosting, you should also create symbolic links
from the numeric addresses to the names, like so:
ln -s www.acme.com 192.100.66.1
ln -s www.joe.acme.com 192.100.66.200
ln -s www.jane.acme.com 192.100.66.201
This lets the older HTTP/1.0 browsers find the right subdirectory.
There's an optional alternate step three if you're using multiple-IP multihosting: run a
separate mini_httpd process for each hostname, using the -h flag to specify which one is
which. This gives you more flexibility, since you can run each of these processes in
separate directories or with different options. Example:
( cd /usr/www ; mini_httpd -h www.acme.com )
( cd /usr/www/joe ; mini_httpd -u joe -h www.joe.acme.com )
( cd /usr/www/jane ; mini_httpd -u jane -h www.jane.acme.com )
But remember, this multiple-process method does not work with CNAME multihosting ‐ for
that, you must use a single mini_httpd process with the -v flag.
CUSTOM ERRORS
mini_httpd lets you define your own custom error pages for the various HTTP errors.
There's a separate file for each error number, all stored in one special directory. The
directory name is "errors", at the top of the web directory tree. The error files should
be named "errNNN.html", where NNN is the error number. So for example, to make a custom
error page for the authentication failure error, which is number 401, you would put your
HTML into the file "errors/err401.html". If no custom error file is found for a given
error number, then the usual built-in error page is generated.
If you're using the virtual hosts option, you can also have different custom error pages
for each different virtual host. In this case you put another "errors" directory in the
top of that virtual host's web tree. mini_httpd will look first in the virtual host
errors directory, and then in the server-wide errors directory, and if neither of those
has an appropriate error file then it will generate the built-in error.
NON-LOCAL REFERRERS
Sometimes another site on the net will embed your image files in their HTML files, which
basically means they're stealing your bandwidth. You can prevent them from doing this by
using non-local referrer filtering. With this option, certain files can only be fetched
via a local referrer. The files have to be referenced by a local web page. If a web page
on some other site references the files, that fetch will be blocked. There are three
config-file variables for this feature:
urlpat A wildcard pattern for the URLs that should require a local referrer. This is
typically just image files, sound files, and so on. For example:
urlpat=**.jpg|**.gif|**.au|**.wav
For most sites, that one setting is all you need to enable referrer filtering.
noemptyreferrers
By default, requests with no referrer at all, or a null referrer, or a referrer
with no apparent hostname, are allowed. With this variable set, such requests are
disallowed.
localpat
A wildcard pattern that specifies the local host or hosts. This is used to
determine if the host in the referrer is local or not. If not specified it
defaults to the actual local hostname.
SIGNALS
mini_httpd will terminate cleanly upon receipt of a number of different signals, which you
can send via the standard Unix kill(1) command. Any of SIGTERM, SIGINT, or SIGUSR1 will
do the trick. All requests in progress will be completed. The network socket used to
accept new connections gets closed immediately, which means a fresh mini_httpd can be
started up right away. This is convenient when you're rotating your log files.
In addition, a SIGHUP will attempt to close and re-open the log file. This is a little
tricky to set up correctly, for instance if you are using chroot() then the log file must
be within the chroot tree, but it's definitely doable.
CERTIFICATES
If you're going to serve SSL/HTTPS you will need a server certificate. There are a bunch
of companies that will issue one for you; see the lists at http://www.apache-
ssl.org/#Digital_Certificates and http://www.modssl.org/docs/2.4/ssl_faq.html#ToC23
You can also create one for yourself, using the openssl tool. Step one - create the key
and certificate request:
openssl req -new > cert.csr
Step two ‐ remove the passphrase from the key:
openssl rsa -in privkey.pem -out key.pem
Step three ‐ convert the certificate request into a signed certificate:
openssl x509 -in cert.csr -out cert.pem -req -signkey key.pem -days 365
This creates four files. The ones you want are cert.pem and key.pem. You don't need
cert.csr and privkey.pem, and may remove them.
SEE ALSO
htpasswd(1), weblog_parse(1), http_get(1)
AUTHOR
Copyright © 1999,2000 by Jef Poskanzer <jef@mail.acme.com>. All rights reserved.
05 October 1999 mini_httpd(8)