221 lines
7.1 KiB
Scheme
221 lines
7.1 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2018 Mathieu Othacehe <m.othacehe@gmail.com>
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;;; Copyright © 2019, 2020 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu installer utils)
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#:use-module (guix utils)
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#:use-module (guix build utils)
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#:use-module (guix i18n)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-34)
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#:use-module (ice-9 match)
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#:use-module (ice-9 rdelim)
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#:use-module (ice-9 regex)
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#:use-module (ice-9 format)
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#:use-module (ice-9 textual-ports)
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#:export (read-lines
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read-all
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nearest-exact-integer
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read-percentage
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run-shell-command
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syslog-port
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syslog
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with-server-socket
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current-server-socket
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current-clients
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send-to-clients))
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(define* (read-lines #:optional (port (current-input-port)))
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"Read lines from PORT and return them as a list."
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(let loop ((line (read-line port))
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(lines '()))
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(if (eof-object? line)
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(reverse lines)
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(loop (read-line port)
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(cons line lines)))))
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(define (read-all file)
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"Return the content of the given FILE as a string."
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(call-with-input-file file
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get-string-all))
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(define (nearest-exact-integer x)
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"Given a real number X, return the nearest exact integer, with ties going to
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the nearest exact even integer."
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(inexact->exact (round x)))
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(define (read-percentage percentage)
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"Read PERCENTAGE string and return the corresponding percentage as a
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number. If no percentage is found, return #f"
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(let ((result (string-match "^([0-9]+)%$" percentage)))
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(and result
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(string->number (match:substring result 1)))))
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(define* (run-shell-command command #:key locale)
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"Run COMMAND, a string, with Bash, and in the given LOCALE. Return true if
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COMMAND exited successfully, #f otherwise."
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(define (pause)
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(format #t (G_ "Press Enter to continue.~%"))
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(send-to-clients '(pause))
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(match (select (cons (current-input-port) (current-clients))
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'() '())
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(((port _ ...) _ _)
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(read-line port))))
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(call-with-temporary-output-file
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(lambda (file port)
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(when locale
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(let ((supported? (false-if-exception
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(setlocale LC_ALL locale))))
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;; If LOCALE is not supported, then set LANGUAGE, which might at
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;; least give us translated messages.
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(if supported?
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(format port "export LC_ALL=\"~a\"~%" locale)
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(format port "export LANGUAGE=\"~a\"~%"
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(string-take locale
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(string-index locale #\_))))))
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(format port "exec ~a~%" command)
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(close port)
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(guard (c ((invoke-error? c)
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(newline)
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(format (current-error-port)
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(G_ "Command failed with exit code ~a.~%")
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(invoke-error-exit-status c))
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(syslog "command ~s failed with exit code ~a"
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command (invoke-error-exit-status c))
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(pause)
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#f))
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(syslog "running command ~s~%" command)
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(invoke "bash" "--init-file" file)
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(syslog "command ~s succeeded~%" command)
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(newline)
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(pause)
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#t))))
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;;;
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;;; Logging.
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;;;
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(define (open-syslog-port)
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"Return an open port (a socket) to /dev/log or #f if that wasn't possible."
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(let ((sock (socket AF_UNIX SOCK_DGRAM 0)))
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(catch 'system-error
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(lambda ()
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(connect sock AF_UNIX "/dev/log")
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(setvbuf sock 'line)
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sock)
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(lambda args
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(close-port sock)
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#f))))
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(define syslog-port
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(let ((port #f))
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(lambda ()
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"Return an output port to syslog."
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(unless port
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(set! port (open-syslog-port)))
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(or port (%make-void-port "w")))))
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(define-syntax syslog
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(lambda (s)
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"Like 'format', but write to syslog."
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(syntax-case s ()
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((_ fmt args ...)
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(string? (syntax->datum #'fmt))
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(with-syntax ((fmt (string-append "installer[~d]: "
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(syntax->datum #'fmt))))
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#'(format (syslog-port) fmt (getpid) args ...))))))
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;;;
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;;; Client protocol.
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;;;
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(define %client-socket-file
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;; Unix-domain socket where the installer accepts connections.
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"/var/guix/installer-socket")
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(define current-server-socket
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;; Socket on which the installer is currently accepting connections, or #f.
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(make-parameter #f))
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(define current-clients
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;; List of currently connected clients.
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(make-parameter '()))
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(define* (open-server-socket
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#:optional (socket-file %client-socket-file))
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"Open SOCKET-FILE as a Unix-domain socket to accept incoming connections and
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return it."
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(mkdir-p (dirname socket-file))
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(when (file-exists? socket-file)
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(delete-file socket-file))
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(let ((sock (socket AF_UNIX SOCK_STREAM 0)))
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(bind sock AF_UNIX socket-file)
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(listen sock 0)
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sock))
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(define (call-with-server-socket thunk)
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(if (current-server-socket)
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(thunk)
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(let ((socket (open-server-socket)))
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(dynamic-wind
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(const #t)
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(lambda ()
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(parameterize ((current-server-socket socket))
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(thunk)))
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(lambda ()
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(close-port socket))))))
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(define-syntax-rule (with-server-socket exp ...)
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"Evaluate EXP with 'current-server-socket' parameterized to a currently
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accepting socket."
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(call-with-server-socket (lambda () exp ...)))
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(define* (send-to-clients exp)
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"Send EXP to all the current clients."
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(define remainder
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(fold (lambda (client remainder)
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(catch 'system-error
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(lambda ()
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(write exp client)
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(newline client)
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(force-output client)
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(cons client remainder))
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(lambda args
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;; We might get EPIPE if the client disconnects; when that
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;; happens, remove CLIENT from the set of available clients.
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(let ((errno (system-error-errno args)))
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(if (memv errno (list EPIPE ECONNRESET ECONNABORTED))
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(begin
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(syslog "removing client ~s due to ~s while replying~%"
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(fileno client) (strerror errno))
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(false-if-exception (close-port client))
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remainder)
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(cons client remainder))))))
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'()
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(current-clients)))
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(current-clients (reverse remainder))
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exp)
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