;; The Right-Awful Gemini Server
-;;
+;;
+;; This is a gemini server in the spirit of the
+;; scratchy gopher server. Just as for that server,
+;; rags uses runtime evaluation of embedded scheme
+;; expressions to provide dynamically generated content.
+;;
+;; See the readme for details.
(import (chicken io)
(chicken port)
(chicken time posix)
(chicken process)
(chicken process-context)
- matchable srfi-13
+ (chicken process-context posix)
+ matchable srfi-13 srfi-1
uri-common tcp6 openssl)
(define-record config
- root-dir host port certfile keyfile)
+ root-dir host port certfile keyfile uid gid)
(define file-types
'(("gmi" "text/gemini" "charset=utf-8")
- ("txt" "text/plain" "charset=utf-8")))
+ ("txt" "text/plain" "charset=utf-8")
+ ("xml" "text/xml" "charset=utf-8")))
(define (process-request config request-line)
(let ((uri (uri-normalize-path-segments (absolute-uri request-line))))
(fail-permanent "Path must be absolute."))
((not (document-available? config uri))
(fail-permanent "Document not found."))
+ ((and (document-path-directory? config uri)
+ (uri-lacks-trailing-slash? uri))
+ (redirect-permanent (uri-with-trailing-slash uri)))
(else
(serve-document config uri)))))
(define (fail-permanent reason)
(print "50 " reason "\r"))
+(define (redirect-permanent new-uri)
+ (print "30 " (uri->string new-uri) "\r"))
+
+(define (uri-lacks-trailing-slash? uri)
+ (not (string-null? (last (uri-path uri)))))
+
+(define (uri-with-trailing-slash uri)
+ (update-uri uri path: (append (uri-path uri) '(""))))
+
(define (document-available? config uri)
(file-exists? (document-path config uri)))
+(define (document-path-directory? config uri)
+ (directory-exists? (document-path-raw config uri)))
+
+(define (document-path-raw config uri)
+ (let* ((crumbs (reverse (cons (config-root-dir config) (cdr (uri-path uri))))))
+ (make-pathname (reverse (cdr crumbs)) (car crumbs))))
+
(define (document-path config uri)
- (let* ((crumbs (reverse (cons (config-root-dir config) (cdr (uri-path uri)))))
- (path (make-pathname (reverse (cdr crumbs)) (car crumbs))))
+ (let* ((path (document-path-raw config uri)))
(if (directory-exists? path)
(make-pathname path "index.gmi")
path)))
(mime-type (cadr mime)))
(print "20 " (string-intersperse (cdr mime) ";") "\r")
(cond
- ((and (equal? mime-type "text/gemini")
- (file-executable? path))
- (serve-text-dynamic path))
+ ((file-executable? path)
+ (serve-text-dynamic path)) ; Binary-files can also be generated here, but the source is dynamic text
((string-prefix? "text/" mime-type)
(serve-text-plain path))
(else (serve-binary path)))))
(signal o)))))
(define (run-server config)
- (define listener (ssl-listen* hostname: (config-host config)
- port: (config-port config)
+ (set-buffering-mode! (current-output-port) #:line)
+ (define listener (ssl-listen* port: (config-port config)
certificate: (config-certfile config)
- private-key: (config-keyfile config)))
+ private-key: (config-keyfile config)
+ protocol: 'tlsv12))
(print "Host: '" (config-host config) "'\n"
"Port: '" (config-port config) "'\n"
"\n"
"Gemini server listening ...")
+ (drop-privs config)
(server-loop listener config))
+(define (drop-privs config)
+ (let ((uid (config-uid config))
+ (gid (config-gid config)))
+ (if gid ; Group first, since only root can switch groups.
+ (set! (current-group-id) gid))
+ (if uid
+ (set! (current-user-id) uid))))
+
+
(define (server-loop listener config)
(let-values (((in-port out-port) (ssl-accept listener)))
(let-values (((local-ip remote-ip) (tcp-addresses (ssl-port->tcp-port in-port))))
(define (print-usage progname)
- (print "Usage: " progname " [-h] [-p port] server-root-dir hostname certfile keyfile"))
+ (let ((indent-str (make-string (string-length progname) #\space)))
+ (print "Usage:\n"
+ progname " [-h/--help]\n"
+ progname " [-p/--port PORT] [-u/--user UID] [-g/--group GID]\n"
+ indent-str " server-root-dir hostname certfile keyfile")))
(define (main)
(let* ((progname (pathname-file (car (argv))))
- (config (make-config #f #f 1965 #f #f)))
+ (config (make-config #f #f 1965 #f #f #f #f)))
(if (null? (cdr (argv)))
(print-usage progname)
(let loop ((args (cdr (argv))))
(print-usage progname))
((or (equal? this-arg "-p")
(equal? this-arg "--port"))
- (config-port-set! config (string->bumber (car rest-args)))
+ (config-port-set! config (string->number (car rest-args)))
+ (loop (cdr rest-args)))
+ ((or (equal? this-arg "-u")
+ (equal? this-arg "--user"))
+ (config-uid-set! config (string->number (car rest-args)))
+ (loop (cdr rest-args)))
+ ((or (equal? this-arg "-g")
+ (equal? this-arg "--group"))
+ (config-gid-set! config (string->number (car rest-args)))
(loop (cdr rest-args)))
(else
(print-usage progname)))