aboutsummaryrefslogtreecommitdiff
path: root/src/fs/gnunet-download-manager.scm
blob: a7cacffd95572b7d5624345bb1c30879adb3633a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
#!/bin/sh
exec guile -e main -s "$0" "$@"
!#

;;;    gnunet-download-manager -- Manage GNUnet downloads.
;;;    Copyright (C) 2004  Ludovic Court�s
;;;
;;;    This program is free software; you can redistribute it and/or
;;;    modify it under the terms of the GNU General Public License
;;;    as published by the Free Software Foundation; either version 2
;;;    of the License, or (at your option) any later version.
;;;   
;;;    This program is distributed in the hope that it will be useful,
;;;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;;    GNU General Public License for more details.
;;;   
;;;    You should have received a copy of the GNU General Public License
;;;    along with this program; if not, write to the Free Software
;;;    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.

;;; Remember ongoing GNUnet downloads so as to be able to resume them
;;; later.  Typical usage is to define the following alias in your
;;; favorite shell:
;;;
;;;    alias gnunet-download='gnunet-download-manager.scm download'
;;;
;;; You may have a ~/.gnunet-download-manager.scm Scheme configuration
;;; file.  In particular, if you would like to be notified of
;;; completed downloads, you may want to add the following line to
;;; your configuration file:
;;;
;;;   (add-hook! *completed-download-hook*
;;;               completed-download-notification-hook)
;;;
;;; This script works fine with GNU Guile 1.6.4, and doesn't run with
;;; Guile 1.4.x.
;;;
;;; Enjoy!
;;; Ludovic Court�s <ludo@chbouib.org>

(use-modules (ice-9 format)
	     (ice-9 optargs)
	     (ice-9 regex)
	     (ice-9 and-let-star)
	     (ice-9 pretty-print)
	     (ice-9 documentation))

;; Overall user settings
(define *debug?* #f)
(define *rc-file* (string-append (getenv "HOME")
				 "/.gnunet-download-manager.scm"))
(define *status-directory* (string-append (getenv "HOME") "/"
					  ".gnunet-download-manager"))
(define *gnunet-download* "gnunet-download")

;; Helper macros
(define-macro (gnunet-info fmt . args)
  `(format #t (string-append *program-name* ": " ,fmt "~%")
	   ,@args))

(define-macro (gnunet-debug fmt . args)
  (if *debug?*
      (cons 'gnunet-info (cons fmt args))
      #t))

(define-macro (gnunet-error fmt . args)
  `(and ,(cons 'gnunet-info (cons fmt args))
	(exit 1)))

(define (exception-string key args)
  "Describe an error, using the format from @var{args}, if available."
  (if (< (length args) 4)
      (format #f "Scheme exception: ~S" key)
      (string-append
       (if (string? (car args))
	   (string-append "In " (car args))
	   "Scheme exception")
       ": "
       (apply format `(#f ,(cadr args) ,@(caddr args))))))


;; Regexps matching GNUnet URIs
(define *uri-base*
  "([[:alnum:]]+).([[:alnum:]]+).([[:alnum:]]+).([0-9]+)")
(define *uri-re*
  (make-regexp (string-append "^gnunet://fs/chk/" *uri-base* "$")
	       regexp/extended))
(define *uri-status-file-re*
  (make-regexp (string-append "^" *uri-base* "$")
	       regexp/extended))


(define (uri-status-file-name directory uri)
  "Return the name of the status file for URI @var{uri}."
  (let ((match (regexp-exec *uri-re* uri)))
    (if (not match)
	(and (gnunet-info "~a: Invalid URI" uri) #f)
	(let ((start (match:start match 1))
	      (end   (match:end   match 4)))
	  (string-append directory "/"
			 (substring uri start end))))))
  
(define (uri-status directory uri)
  "Load the current status alist for URI @var{uri} from @var{directory}."
  (gnunet-debug "uri-status")
  (let ((filename (uri-status-file-name directory uri)))
    (catch 'system-error
	   (lambda ()
	     (let* ((file (open-input-file filename))
		    (status (read file)))
	       (begin
		 (close-port file)
		 status)))
	   (lambda (key . args)
	     (and (gnunet-debug (exception-string key args))
		  '())))))

(define (process-exists? pid)
  (false-if-exception (begin (kill pid 0) #t)))

(define (fork-and-exec directory program . args)
  "Launch @var{program} and return its PID."
  (gnunet-debug "fork-and-exec: ~a ~a" program args)
  (let ((pid (primitive-fork)))
    (if (= 0 pid)
	(begin
	  (if directory (chdir directory))
	  (apply execlp (cons program (cons program args))))
	pid)))

(define* (start-downloader downloader uri options
			   #:key (directory #f))
  "Start the GNUnet downloader for URI @var{uri} with options
@var{options}.  Return an alist describing the download status."
  (catch 'system-error
	 (lambda ()
	   (let* ((pid (apply fork-and-exec
			      `(,(if directory directory (getcwd))
				,downloader
				,@options))))
	     (gnunet-info "Launched process ~a" pid)
	     `((uri . ,uri)
	       (working-directory . ,(if directory directory (getcwd)))
	       (options . ,options)
	       (pid . ,(getpid))
	       (downloader-pid . ,pid))))
	 (lambda (key . args)
	   (gnunet-error (exception-string key args)))))

(define (download-process-alive? uri-status)
  "Return true if the download whose status is that described by
@var{uri-status} is still alive."
  (let ((pid (assoc-ref uri-status 'pid))
	(downloader-pid (assoc-ref uri-status 'downloader-pid)))
    (and (process-exists? pid)
	 (process-exists? downloader-pid))))

(define (start-file-download downloader status-dir uri options)
  "Dowload the file located at @var{uri}, with options @var{options}
and return an updated status alist."
  (gnunet-debug "start-file-download")
  (let ((uri-status (uri-status status-dir uri)))
    (if (null? uri-status)
	(acons 'start-date (current-time)
	       (start-downloader downloader uri options))
	(if (download-process-alive? uri-status)
	    (and (gnunet-info "~a already being downloaded by process ~a"
			      uri (assoc-ref uri-status 'pid))
		 #f)
	    (and (gnunet-info "Resuming download")
		 (let ((start-date (assoc-ref uri-status 'start-date))
		       (dir (assoc-ref uri-status 'working-directory))
		       (options (assoc-ref uri-status 'options)))
		   (acons 'start-date start-date
			  (start-downloader downloader uri options
					    #:directory dir))))))))

(define *completed-download-hook* (make-hook 1))

(define (download-file downloader status-dir uri options)
  "Start downloading file located at URI @var{uri}, with options
@var{options}, resuming it if it's already started."
  (catch 'system-error
	 (lambda ()
	   (and-let* ((status (start-file-download downloader
						   status-dir
						   uri options))
		      (pid (assoc-ref status 'downloader-pid))
		      (filename (uri-status-file-name status-dir
						      uri))
		      (file (open-file filename "w")))

		     ;; Write down the status
		     (pretty-print status file)
		     (close-port file)

		     ;; Wait for `gnunet-download'
		     (gnunet-info "Waiting for process ~a" pid)
		     (let* ((process-status (waitpid pid))
			    (exit-val (status:exit-val (cdr process-status)))
			    (term-sig (status:term-sig (cdr process-status))))

		       ;; Terminate
		       (delete-file filename)
		       (gnunet-info
			"Download completed (PID ~a, exit code ~a)"
			pid exit-val)
		       (let ((ret `((end-date . ,(current-time))
				    (exit-code . ,exit-val)
				    (terminating-signal . ,term-sig)
				    ,@status)))
			 (run-hook *completed-download-hook* ret)
			 ret))))
	   (lambda (key . args)
	     (gnunet-error (exception-string key args)))))

(define (uri-status-files directory)
  "Return the list of URI status files in @var{directory}."
  (catch 'system-error
	 (lambda ()
	   (let ((dir (opendir directory)))
	     (let loop ((filename (readdir dir))
			(file-list '()))
	       (if (eof-object? filename)
		   file-list
		   (if (regexp-exec *uri-status-file-re* filename)
		       (loop (readdir dir)
			     (cons filename file-list))
		       (loop (readdir dir) file-list))))))
	 (lambda (key . args)
	   (gnunet-error (exception-string key args)))))

(define (output-file-option option-list)
  "Return the output file specified in @var{option-list}, false if
anavailable."
  (if (null? option-list)
      #f
      (let ((rest (cdr option-list))
	    (opt (car option-list)))
	(if (null? rest)
	    #f
	    (if (or (string=? opt "-o")
		    (string=? opt "--output"))
		(car rest)
		(output-file-option rest))))))

(define (download-command . args)
  "Start downloading a file using the given `gnunet-download'
arguments."
  (gnunet-debug "download-command")
  (let* ((argc (length args))
	 ;; FIXME: We're assuming the URI is the last argument
	 (uri (car (list-tail args (- argc 1))))
	 (options args))
    (download-file *gnunet-download* *status-directory* uri options)))

(define (status-command . args)
  "Print status info about files being downloaded."
  (for-each (lambda (status)
	      (format #t "~a: ~a~%  ~a~%  ~a~%  ~a~%"
		      (assoc-ref status 'uri)
		      (if (download-process-alive? status)
			  (string-append "running (PID "
					 (number->string (assoc-ref status
								    'pid))
					 ")")
			  "not running")
		      (string-append "Started on "
				     (strftime "%c"
					       (localtime (assoc-ref
							   status
							   'start-date))))
		      (string-append "Directory:   "
				     (assoc-ref status
						'working-directory))
		      (string-append "Output file: "
				     (or (output-file-option (assoc-ref
							      status
							      'options))
					 "<unknown>"))))
	    (map (lambda (file)
		   (uri-status *status-directory*
			       (string-append "gnunet://fs/chk/" file)))
		 (uri-status-files *status-directory*))))

(define (resume-command . args)
  "Resume stopped downloads."
  (for-each (lambda (status)
	      (if (not (download-process-alive? status))
		  (if (= 0 (primitive-fork))
		      (let* ((ret (download-file *gnunet-download*
						 *status-directory*
						 (assoc-ref status 'uri)
						 (assoc-ref status 'options)))
			     (code (assoc-ref ret 'exit-code)))
			(exit code)))))
	    (map (lambda (file)
		   (uri-status *status-directory*
			       (string-append "gnunet://fs/chk/" file)))
		 (uri-status-files *status-directory*))))

(define (killall-command . args)
  "Stop all running downloads."
  (for-each (lambda (status)
	      (if (download-process-alive? status)
		  (let ((pid (assoc-ref status 'pid))
			(dl-pid (assoc-ref status 'downloader-pid)))
		    (and (gnunet-info "Stopping processes ~a and ~a"
				      pid dl-pid)
			 (kill pid 15)
			 (kill dl-pid 15)))))
	    (map (lambda (file)
		   (uri-status *status-directory*
			       (string-append "gnunet://fs/chk/" file)))
		 (uri-status-files *status-directory*))))


(define (help-command . args)
  "Show this help message."
  (format #t "Usage: ~a <command> [options]~%" *program-name*)
  (format #t "Where <command> may be one of the following:~%~%")
  (for-each (lambda (command)
	      (if (not (eq? (cdr command) help-command))
		  (format #t (string-append "   " (car command) ": "
					    (object-documentation
					     (cdr command))
					    "~%"))))
	    *commands*)
  (format #t "~%"))

(define (settings-command . args)
  "Dump the current settings."
  (format #t "Current settings:~%~%")
  (module-for-each (lambda (symbol variable)
		     (if (string-match "^\\*.*\\*$" (symbol->string symbol))
			 (format #t "   ~a: ~a~%"
				 symbol (variable-ref variable))))
		   (current-module))
  (format #t "~%"))

(define (version-command . args)
  "Show version information."
  (format #t "~a ~a.~a (~a)~%"
	  *program-name* *version-major* *version-minor* *version-date*))

;; This hook may be added to *completed-download-hook*.
(define (completed-download-notification-hook status)
  "Notifies of the completion of a file download."
  (let ((msg (string-append "GNUnet download of "
			    (output-file-option
			     (assoc-ref status 'options))
			    " in "
			    (assoc-ref status
				       'working-directory)
			    " complete!")))
    (if (getenv "DISPLAY")
	(waitpid (fork-and-exec #f "xmessage" msg))
	(waitpid (fork-and-exec #f "write"
				(cuserid) msg)))))

;; Available user commands
(define *commands*
  `(("download" . ,download-command)
    ("status"   . ,status-command)
    ("resume"   . ,resume-command)
    ("killall"  . ,killall-command)
    ("settings" . ,settings-command)
    ("version"  . ,version-command)
    ("help"     . ,help-command)
    ("--help"   . ,help-command)
    ("-h"       . ,help-command)))

(define *program-name* "gnunet-download-manager")
(define *version-major* 0)
(define *version-minor* 1)
(define *version-date* "april 2004")

(define (main args)
  (set! *program-name* (basename (car args)))

  ;; Load the user's configuration file
  (if (file-exists? *rc-file*)
      (load *rc-file*))

  ;; Check whether the status directory already exists
  (if (not (file-exists? *status-directory*))
      (begin
	(gnunet-info "Creating status directory ~a..." *status-directory*)
	(catch 'system-error
	       (lambda ()
		 (mkdir *status-directory*))
	       (lambda (key . args)
		 (and (gnunet-error (exception-string key args))
		      (exit 1))))))

  ;; Go ahead
  (if (< (length args) 2)
      (and (format #t "Usage: ~a <command> [options]~%"
		   *program-name*)
	   (exit 1))
      (let* ((command-name (cadr args))
	     (command (assoc-ref *commands* command-name)))
	(if command
	    (apply command (cddr args))
	    (and (gnunet-info "~a command not found" command-name)
		 (exit 1))))))