adding Ludo's gnunet-download-manager.scm back to SVN HEAD

1 files changed, 407 insertions, 0 deletions

diff --git a/src/fs/gnunet-download-manager.scm b/src/fs/gnunet-download-manager.scm
new file mode 100755
index 000000000..80d04fa12
--- /dev/null
+++ b/src/fs/gnunet-download-manager.scm
@@ -0,0 +1,407 @@
+#!/bin/sh
+exec guile -e main -s "$0" "$@"
+!#
+
+;;;    gnunet-download-manager -- Manage GNUnet downloads.
+;;;    Copyright (C) 2004  Ludovic Courtès
+;;;
+;;;    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., 675 Mass Ave, Cambridge, MA 02139, 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 Courtès <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://afs/" *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://afs/" 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://afs/" 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://afs/" 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))))))
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