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1 .\" Copyright (c) 2021 Omar Polo <op@omarpolo.com>
2 .\"
3 .\" Permission to use, copy, modify, and distribute this software for any
4 .\" purpose with or without fee is hereby granted, provided that the above
5 .\" copyright notice and this permission notice appear in all copies.
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7 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
10 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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12 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
13 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14 .Dd $Mdocdate: January 30 2021$
15 .Dt GMIND 1
16 .Os
17 .Sh NAME
18 .Nm gmid
19 .Nd simple and secure Gemini server
20 .Sh SYNOPSIS
21 .Nm
22 .Bk -words
23 .Op Fl fnv
24 .Op Fl c Ar config
25 .Ek
26 .Nm
27 .Bk -words
28 .Op Fl 6hv
29 .Op Fl d Pa certs-dir
30 .Op Fl H Ar hostname
31 .Op Fl p Ar port
32 .Op Fl x Pa cgi
33 .Op Pa dir
34 .Ek
35 .Sh DESCRIPTION
36 .Nm
37 is a simple and minimal gemini server that can serve static files and
38 execute CGI scripts.
39 It can run without a configuration file with a limited set of features
40 available.
41 .Pp
42 .Nm
43 rereads the configuration file when it receives
44 .Dv SIGHUP .
45 .Pp
46 The options are as follows:
47 .Bl -tag -width 14m
48 .It Fl c Pa config
49 Specify the configuration file.
50 .It Fl f
51 Stays and logs on the foreground.
52 .It Fl n
53 Check that the configuration is valid, but don't start the server.
54 .El
55 .Pp
56 If no configuration file is given,
57 .Nm
58 will look for the following options
59 .Bl -tag -width 14m
60 .It Fl 6
61 Enable IPv6.
62 .It Fl d Pa certs-path
63 Directory where certificates for the config-less mode are stored.
64 By default is
65 .Pa $XDG_DATA_HOME/gmid ,
66 i.e.
67 .Pa ~/.local/share/gmid .
68 .It Fl H Ar hostname
69 The hostname, by default
70 .Ar localhost .
71 Certificates for the given
72 .Ar hostname
73 are searched inside the
74 .Pa certs-dir
75 directory given with the
76 .Fl d
77 option.
78 They have the form
79 .Pa hostname.cert.pem
80 and
81 .Pa hostname.key.pem .
82 If a certificate and key doesn't exists for a given hostname they
83 will be automatically generated.
84 .It Fl h
85 Print the usage and exit.
86 .It Fl p Ar port
87 The port to listen on, by default 1965.
88 .It Fl v
89 Increase the verbosity of the logs.
90 .It Fl x Pa path
91 Enable execution of CGI scripts.
92 See the description of the
93 .Ic cgi
94 option in the section
95 .Sq Servers
96 below to learn how
97 .Pa path
98 is processed.
99 Cannot be provided more than once.
100 .It Pa dir
101 The root directory to serve.
102 By default the current working directory is assumed.
103 .El
104 .Sh CONFIGURATION FILE
105 The configuration file is divided into two sections:
106 .Bl -tag -width xxxx
107 .It Sy Global Options
108 Global settings for
109 .Nm .
110 .It Sy Servers
111 Virtual hosts definition.
112 .El
113 .Pp
114 Within the sections, empty lines are ignored and comments can be put
115 anywhere in the file using a hash mark
116 .Pq Sq # ,
117 and extend to the end of the current line.
118 A boolean is either the symbol
119 .Sq on
120 or
121 .Sq off .
122 A string is a sequence of characters wrapped in double quotes,
123 .Dq like this .
124 .Ss Global Options
125 .Bl -tag -width 12m
126 .It Ic ipv6 Ar bool
127 Enable or disable IPv6 support.
128 By default is off.
129 .It Ic port Ar portno
130 The port to listen on.
131 By default is 1965.
132 .It Ic protocols Ar string
133 Specify the TLS protocols to enable.
134 Refer to
135 .Xr tls_config_parse_protocols 3
136 for the valid protocol string values.
137 By default, both TLSv1.3 and TLSv1.2 are enabled.
138 Use
139 .Dq tlsv1.3
140 to enable only TLSv1.3.
141 .It Ic mime Ar mime-type Ar file-extension
142 Add a mapping for the given
143 .Ar file-extension
144 to the given
145 .Ar mime-type .
146 Both argument are strings.
147 .It Ic chroot Pa path
148 .Xr chroot 2
149 the process to the given
150 .Pa path .
151 The daemon has to be run with root privileges and thus the option
152 .Ic user
153 needs to be provided, so privileges can be dropped.
154 Note that
155 .Nm
156 will enter the chroot after loading the TLS keys, but before opening
157 the virtual host root directories.
158 It's recommended to keep the TLS keys outside the chroot.
159 Future version of
160 .Nm
161 may require this.
162 .It Ic user Ar string
163 Run the daemon as the given user.
164 .El
165 .Ss Servers
166 Every virtual host is defined by a
167 .Ic server
168 block:
169 .Bl -tag -width Ds
170 .It Ic server Ar hostname Brq ...
171 Match the server name using shell globbing rules.
172 This can be an explicit name,
173 .Ar www.example.com ,
174 or a name including a wildcards,
175 .Ar *.example.com .
176 .El
177 .Pp
178 Followed by a block of options that is enclosed in curly brackets:
179 .Bl -tag -width Ds
180 .It Ic cert Pa file
181 Path to the certificate to use for this server.
182 The
183 .Pa file
184 should contain a PEM encoded certificate.
185 This option is mandatory.
186 .It Ic key Pa file
187 Specify the private key to use for this server.
188 The
189 .Pa file
190 should contain a PEM encoded private key.
191 This option is mandatory.
192 .It Ic root Pa directory
193 Specify the root directory for this server.
194 This option is mandatory.
195 It's relative to the chroot, if enabled.
196 .It Ic cgi Pa path
197 Execute CGI scripts that matches
198 .Pa path
199 using shell globbing rules.
200 .It Ic default type Ar string
201 Set the default media type that is used if the media type for a
202 specified extension is not found.
203 If not specified, the
204 .Ic default type
205 is set to
206 .Dq application/octet-stream .
207 .It Ic lang Ar string
208 Specify the language tag for the text/gemini content served.
209 If not specified, no
210 .Dq lang
211 parameter will be added in the response.
212 .It Ic index Ar string
213 Set the directory index file.
214 If not specified, it defaults to
215 .Pa index.gmi .
216 .It Ic auto Ic index Ar bool
217 If no index file is found, automatically generate a directory listing.
218 It's disabled by default.
219 .It Ic location Pa path Brq ...
220 Specify server configuration rules for a specific location.
221 The
222 .Pa path
223 argument will be matched against the request path with shell globbing
224 rules.
225 In case of multiple location statements in the same context, the first
226 matching location will be put into effect and the later ones ignored.
227 Therefore is advisable to match for more specific paths first and for
228 generic ones later on.
230 .Ic location
231 section may include most of the server configuration rules
232 except
233 .Ic cert , Ic key , Ic root , Ic location No and Ic cgi .
234 .El
235 .Sh CGI
236 When a request for an executable file matches the
237 .Ic cgi
238 rule, that file will be execute and its output fed to the client.
239 .Pp
240 The CGI scripts are executed in the directory they reside and inherit
241 the environment from
242 .Nm
243 with these additional variables set:
244 .Bl -tag -width 24m
245 .It Ev GATEWAY_INTERFACE
246 .Dq CGI/1.1
247 .It Ev GEMINI_DOCUMENT_ROOT
248 The root directory of the virtual host.
249 .It Ev GEMINI_SCRIPT_FILENAME
250 Full path to the CGI script being executed.
251 .It Ev GEMINI_URL
252 The full IRI of the request.
253 .It Ev GEMINI_URL_PATH
254 The path of the request.
255 .It Ev PATH_INFO
256 The portion of the requested path that is derived from the the IRI
257 path hierarchy following the part that identifies the script itself.
258 Can be unset.
259 .It Ev PATH_TRANSLATED
260 Present if and only if
261 .Ev PATH_INFO
262 is set.
263 It represent the translation of the
264 .Ev PATH_INFO .
265 .Nm
266 builds this by appending the
267 .Ev PATH_INFO
268 to the virtual host directory root.
269 .It Ev QUERY_STRING
270 The decoded query string.
271 .It Ev REMOTE_ADDR , Ev REMOTE_HOST
272 Textual representation of the client IP.
273 .It Ev REQUEST_METHOD
274 This is present only for RFC3875 (CGI) compliance.
275 It's always set to the empty string.
276 .It Ev SCRIPT_NAME
277 The part of the
278 .Ev GEMINI_URL_PATH
279 that identifies the current CGI script.
280 .It Ev SERVER_NAME
281 The name of the server
282 .It Ev SERVER_PORT
283 The port the server is listening on.
284 .It Ev SERVER_PROTOCOL
285 .Dq GEMINI
286 .It Ev SERVER_SOFTWARE
287 The name and version of the server, i.e.
288 .Dq gmid/1.5
289 .It Ev AUTH_TYPE
290 The string "Certificate" if the client used a certificate, otherwise
291 unset.
292 .It Ev REMOTE_USER
293 The subject of the client certificate if provided, otherwise unset.
294 .It Ev TLS_CLIENT_ISSUER
295 The is the issuer of the client certificate if provided, otherwise
296 unset.
297 .It Ev TLS_CLIENT_HASH
298 The hash of the client certificate if provided, otherwise unset.
299 The format is
300 .Dq ALGO:HASH .
301 .El
302 .Pp
303 .Sh MIME
304 To auto-detect the MIME type of the response
305 .Nm
306 looks at the file extension and consults its internal table.
307 By default the following mappings are loaded, but they can be
308 overridden or extended using the
309 .Ic mime
310 configuration option.
311 If no MIME is found, the value of
312 .Ic default type
313 matching the file
314 .Ic location
315 will be used, which is
316 .Dq application/octet-stream
317 by default.
318 .Pp
319 .Bl -tag -offset indent -width 14m -compact
320 .It gemini, gmi
321 text/gemini
322 .It gif
323 image/gif
324 .It jpeg
325 image/jpeg
326 .It jpg
327 image/jpeg
328 .It markdown, md
329 text/markdown
330 .It pdf
331 application/pdf
332 .It png
333 image/png
334 .It svg
335 image/svg+xml
336 .It txt
337 text/plain
338 .It xml
339 text/xml
340 .El
341 .Sh EXAMPLES
342 Serve the current directory
343 .Bd -literal -offset indent
344 $ gmid .
345 .Ed
346 .Pp
347 To serve the directory
348 .Pa docs
349 and enable CGI scripts inside
350 .Pa docs/cgi ,
351 you can
352 .Bd -literal -offset indent
353 $ mkdir docs/cgi
354 $ cat <<EOF > cgi/hello
355 #!/bin/sh
356 printf "20 text/plain\\r\\n"
357 echo "hello world"
358 EOF
359 $ chmod +x docs/cgi/hello
360 $ gmid -x cgi docs
361 .Ed
362 .Pp
363 The following is an example of a possible configuration for a site
364 that enables only TLSv1.3, adds a mime type for the file extension
365 "rtf" and defines two virtual host:
366 .Bd -literal -offset indent
367 ipv6 on # enable ipv6
369 protocols "tlsv1.3"
371 mime "application/rtf" "rtf"
373 server "example.com" {
374 cert "/path/to/cert.pem"
375 key "/path/to/key.pem"
376 root "/var/gemini/example.com"
379 server "it.example.com" {
380 cert "/path/to/cert.pem"
381 key "/path/to/key.pem"
382 root "/var/gemini/it.example.com"
383 cgi "/cgi-bin/*"
384 lang "it"
386 .Ed
387 .Pp
388 Yet another example, showing how to enable a
389 .Ic chroot
390 and use
391 .Ic location
392 rule
393 .Bd -literal -offset indent
394 chroot "/var/gemini"
395 user "_gmid"
397 server "example.com" {
398 cert "/path/to/cert.pem"
399 key "/path/to/key.pem"
400 root "/example.com" # in the /var/gemini chroot
402 location "/static/*" {
403 auto index on
404 index "index.gemini"
407 .Ed
408 .Sh ACKNOWLEDGEMENTS
409 .Nm
410 uses the
411 .Dq Flexible and Economical
412 UTF-8 decoder written by
413 .An Bjoern Hoehrmann .
414 .Sh AUTHORS
415 .An -nosplit
416 The
417 .Nm
418 program was written by
419 .An Omar Polo Aq Mt op@omarpolo.com .
420 .Sh CAVEATS
421 .Bl -bullet
422 .It
423 The root directories of all virtual hosts are opened during the daemon
424 startup; this means that if a root directory gets deleted and then
425 re-created,
426 .Nm
427 won't be able to serve files inside that directory until a restart.
428 This restriction applies only to the root directories and not their content.
429 .It
430 a %2F sequence is indistinguishable from a literal slash: this is not
431 RFC3986-compliant.
432 .It
433 a %00 sequence is treated as invalid character and thus rejected.
434 .El