1 .\" Copyright (c) 2020 Omar Polo <op@omarpolo.com>
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14 .Dd $Mdocdate: October 2 2020$
15 .Dt GMIND 1
16 .Os
17 .Sh NAME
18 .Nm gmid
19 .Nd dead simple zero configuration gemini server
20 .Sh SYNOPSIS
21 .Nm
22 .Bk -words
23 .Op Fl n
24 .Op Fl c Ar config
25 |
26 .Op Fl 6fh
27 .Op Fl C Ar cert
28 .Op Fl d Ar root
29 .Op Fl K Ar key
30 .Op Fl p Ar port
31 .Op Fl x Ar directory
32 .Ek
33 .Sh DESCRIPTION
34 .Nm
35 is a simple and minimal gemini server that can serve static files and
36 execute CGI scripts.
37 It can run without a configuration file with a limited set of features
38 available.
39 If a configuration file is given, no other flags shall be given,
40 except for
41 .Fl n .
42 .Pp
43 .Nm
44 fully supports IRIs (Internationalized Resource Identifiers, see
45 RFC3987).
46 .Pp
47 The options are as follows:
48 .Bl -tag -width 12m
49 .It Fl c Pa config
50 Specifies the configuration file.
51 .It Fl n
52 Check that the configuration is valid, but don't start the server.
53 .El
54 .Pp
55 If no configuration file is given,
56 .Nm
57 will look for the following option
58 .Bl -tag -width 12m
59 .It Fl 6
60 Enable IPv6.
61 .It Fl C Pa file
62 The certificate to use.
63 .It Fl d Pa directory
64 The root directory to serve.
65 .It Fl f
66 Stays and log in the foreground, do not daemonize the process.
67 .It Fl h
68 Print the usage and exit.
69 .It Fl K Pa file
70 The key for the certificate.
71 .It Fl p Ar port
72 The port to listen on, by default 1965.
73 .It Fl x Pa directory
74 Enable execution of CGI scripts.
75 See the description of the
76 .Ic cgi
77 .Ic server
78 option in the section
79 .Sq Servers
80 below to learn how
81 .Pa directory
82 is processed.
83 Cannot be provided more than once.
84 .El
85 .Sh CONFIGURATION FILE
86 The configuration file is divided into two sections:
87 .Bl -tag -width xxxx
88 .It Sy Global Options
89 Global settings for
90 .Nm .
91 .It Sy Servers
92 Virtual hosts definition
93 .El
94 .Pp
95 Within the sections, empty lines are ignored and comments can be put
96 anywhere in the file using a hash mark
97 .Pq Sq # ,
98 and extend to the end of the current line.
99 A boolean is either the symbol
100 .Sq on
101 or
102 .Sq off .
103 .Ss Global Options
104 .Bl -tag -width 12m
105 .It Ic daemon Ar bool
106 Enable or disables the daemon mode.
107 In daemon mode
108 .Nm
109 will log to syslog and fork in the background.
110 By default is off.
111 .It Ic ipv6 Ar bool
112 Enable or disable IPv6 support.
113 By default is off.
114 .It Ic port Ar portno
115 The port to listen on.
116 By default is 1965.
117 .It Ic protocols Ar string
118 Specify the TLS protocols to enable.
119 Refer to
120 .Xr tls_config_parse_protocols 3
121 for the valid protocol string values.
122 By default, both TLSv1.3 and TLSv1.2 are used.
123 Use
124 .Dq tlsv1.3
125 to enable only TLSv1.3.
126 .It Ic mime Ar mime-type Ar file-extension
127 Add a mapping for the given
128 .Ar file-extension
129 to the given
130 .Ar mime-type .
131 Both argument are strings.
132 .El
133 .Ss Servers
134 Every virtual host is defined by a
135 .Ic server
136 block:
137 .Bl -tag -width Ds
138 .It Ic server Ar hostname Brq ...
139 .El
140 .Pp
141 Followed by a block of options that is enclosed in curly brackets:
142 .Bl -tag -width Ds
143 .It Ic cert Pa file
144 Path to the certificate to use for this server.
145 The
146 .Pa file
147 should contain a PEM encoded certificate.
148 This option is mandatory.
149 .It Ic key Pa file
150 Specify the private key to use for this server.
151 The
152 .Pa file
153 should contain a PEM encoded private key.
154 This option is mandatory.
155 .It Ic root Pa directory
156 Specify the root directory for this server.
157 This option is mandatory.
158 .It Ic cgi Pa path
159 Enable the execution of CGI scripts if
160 .Pa path
161 is a prefix of the user request string.
162 An empty path "" will effectively enable the execution of any file
163 with the executable bit set inside the root directory.
164 .It Ic default type Ar string
165 Set the default media type that is used if the media type for a
166 specified extension is not found.
167 If not specified, the
168 .Ic default type
169 is set to
170 .Dq application/octet-stream .
171 .It Ic lang Ar string
172 Specify the language tag for the text/gemini content served.
173 If not specified, no
174 .Dq lang
175 parameter will be added in the response.
176 .El
177 .Sh CGI
178 When CGI scripts are enabled for a directory, a request for an
179 executable file will execute it and fed its output to the client.
180 .Pp
181 The CGI scripts will inherit the environment from
182 .Nm
183 with these additional variables set:
184 .Bl -tag -width 18m
185 .It Ev SERVER_SOFTWARE
186 "gmid"
187 .It Ev SERVER_PORT
188 "1965"
189 .It Ev SCRIPT_NAME
190 The (public) path to the script.
191 .It Ev SCRIPT_EXECUTABLE
192 The full path to the executable.
193 .It Ev REQUEST_URI
194 The user request (without the query parameters.)
195 .It Ev REQUEST_RELATIVE
196 The request relative to the script.
197 .It Ev QUERY_STRING
198 The query parameters.
199 .It Ev REMOTE_HOST
200 The remote IP address.
201 .It Ev REMOTE_ADDR
202 The remote IP address.
203 .It Ev DOCUMENT_ROOT
204 The root directory being served, the one provided with the
205 .Ar d
206 parameter to
207 .Nm
208 or the root directory of the virtual host.
209 .It Ev AUTH_TYPE
210 The string "Certificate" if the client used a certificate, otherwise unset.
211 .It Ev REMOTE_USER
212 The subject of the client certificate if provided, otherwise unset.
213 .It Ev TLS_CLIENT_ISSUER
214 The is the issuer of the client certificate if provided, otherwise unset.
215 .It Ev TLS_CLIENT_HASH
216 The hash of the client certificate if provided, otherwise unset.
217 The format is "ALGO:HASH".
218 .El
219 .Pp
220 Let's say you have a script in
221 .Pa /cgi-bin/script
222 and the user request is
223 .Pa /cgi-bin/script/foo/bar?quux .
224 Then
225 .Ev SCRIPT_NAME
226 will be
227 .Pa cgi-bin/script ,
228 .Ev SCRIPT_EXECUTABLE
229 will be
230 .Pa $DOCUMENT_ROOT/cgi-bin/script ,
231 .Ev REQUEST_URI
232 will be
233 .Pa cgi-bin/script/foo/bar ,
234 .Ev REQUEST_RELATIVE
235 will be
236 .Pa foo/bar
237 and
238 .Ev QUERY_STRING
239 will be
240 .Ar quux .
241 .Sh EXAMPLES
242 To quickly getting started
243 .Bd -literal -offset indent
244 $ # generate a cert and a key
245 $ openssl req -x509 -newkey rsa:4096 -keyout key.pem \\
246         -out cert.pem -days 365 -nodes
247 $ mkdir docs
248 $ cat <<EOF > docs/index.gmi
249 # Hello world
250 test paragraph...
251 EOF
252 $ gmid -c cert.pem -k key.pem -d docs
253 .Ed
254 .Pp
255 Now you can visit gemini://localhost/ with your preferred gemini
256 client.
257 .Pp
258 To add some CGI scripts, assuming a setup similar to the previous
259 example, you can
260 .Bd -literal -offset indent
261 $ mkdir docs/cgi-bin
262 $ cat <<EOF > docs/cgi-bin/hello-world
263 #!/bin/sh
264 printf "20 text/plain\\r\\n"
265 echo "hello world!"
266 EOF
267 $ gmid -x cgi-bin
268 .Ed
269 .Pp
270 Note that the argument to the
271 .Fl x
272 option is
273 .Pa cgi-bin
274 and not
275 .Pa docs/cgi-bin ,
276 since it's relative to the document root.
277 .Pp
278 The following is an example of a possible configuration for a site
279 that enables only TLSv1.3, adds a mime type for the file extension
280 "rtf" and defines two virtual host:
281 .Bd -literal -offset indent
282 ipv6 on		# enable ipv6
283 daemon on	# enable daemon mode
284 
285 protocols "tlsv1.3"
286 
287 mime "application/rtf" "rtf"
288 
289 server "example.com" {
290 	cert "/path/to/cert.pem"
291 	key  "/path/to/key.pem"
292 	root "/var/gemini/example.com"
293 }
294 
295 server "it.example.com" {
296 	cert "/path/to/cert.pem"
297 	key  "/path/to/key.pem"
298 	root "/var/gemini/it.example.com"
299 	cgi  "/cgi-bin"
300 }
301 .Ed
302 .Sh ACKNOWLEDGEMENTS
303 .Nm
304 uses the
305 .Dq Flexible and Economical
306 UTF-8 decoder written by
307 .An Bjoern Hoehrmann
308 for its IRI parser.
309 .Sh CAVEATS
310 .Bl -bullet
311 .It
312 The root directories of all virtual hosts are opened during the daemon
313 startup; this means that if a root directory gets deleted and then
314 re-created,
315 .Nm
316 won't be able to serve files inside that directory until a restart.
317 This restriction applies only to the root directories and not their content.
318 .It
319 a %2F sequence in the path part is indistinguishable from a literal
320 slash: this is not RFC3986-compliant.
321 .It
322 a %00 sequence either in the path or in the query part is treated as
323 invalid character and thus rejected.
324 .El