75 lines
2.2 KiB
Scheme
75 lines
2.2 KiB
Scheme
; some useful utilities
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;;; This file is part of the Scheme Untergrund Networking package.
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;;; Copyright (c) 2002 by Andreas Bernauer.
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;;; For copyright information, see the file COPYING which comes with
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;;; the distribution.
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(define (host-name-or-ip addr)
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(with-fatal-error-handler
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(lambda (condition more)
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(call-with-values
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(lambda () (socket-address->internet-address addr))
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(lambda (ip port)
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(format-internet-host-address ip))))
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(host-info:name (host-info addr))))
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(define (on-interrupt interrupt thunk)
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(let lp ((event (most-recent-sigevent)))
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(let ((next (next-sigevent event interrupt)))
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(thunk)
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(lp next))))
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(define (socket-address->string socket-address . with-port?)
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(let ((with-port? (:optional with-port? #t)))
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(receive (host-address service-port)
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(socket-address->internet-address socket-address)
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(if with-port?
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(format #f "~A:~A"
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(format-internet-host-address host-address)
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(format-port service-port))
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(format #f "~A"
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(format-internet-host-address host-address))))))
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;;; Assemble a filename from ROOT and the elts of PATH-LIST.
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;;; If the assembled filename contains a .. subdirectory, return #f,
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;;; otw return the filename.
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(define dotdot-check
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(let ((dotdot-re (make-regexp "(^|/)\\.\\.($|/)"))) ; Matches a .. subdir.
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(lambda (root path-list)
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(let ((fname (if (null? path-list) root ; Bogus hack.
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(string-append (file-name-as-directory root)
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(string-join path-list "/")))))
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(and (not (regexp-exec dotdot-re fname)) ; Check for .. subdir.
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fname)))))
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;;; Timeout on network writes?
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(define (copy-inport->outport in out . maybe-buffer-size)
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(let* ((buffer-size (:optional maybe-buffer-size 1024))
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(buf (make-string buffer-size)))
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(let loop ()
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(cond ((read-string! buf in) => (lambda (nchars)
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(write-string buf out 0 nchars)
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(loop)))))
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(force-output out)))
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(define (dump fd)
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(copy-inport->outport fd (current-output-port)))
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(define (with-lock lock thunk)
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(dynamic-wind
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(lambda ()
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(release-lock lock))
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thunk
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(lambda ()
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(release-lock lock))))
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;; Get Header from (RFC822 like) header alist
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(define (get-header headers tag)
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(cond ((assq tag headers) => cdr)
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(else #f))) |