all: Separate programs in different executables.

This improves readability and complies with the GNU Coding Standards by
making the behavior of the programs independent of the name used to
invoke them.

* src/mcron/scripts/cron.scm: New file.
* src/mcron/scripts/crontab.scm: Likewise.
* src/mcron/scripts/mcron.scm: Likewise.
* Makefile.am (dist_mcronmodule_DATA): Remove 'src/mcron/crontab.scm'.
(bin_PROGRAMS): Add 'crontab'.
(sbin_PROGRAMS): Add 'cron'.
(mcron_CFLAGS, mcron_LDADD): Rename to ...
(AM_CFLAGS, LDADD): ... these.
(cron_SOURCES, cron_CPPFLAGS, cron_DEPENDENCIES)
(crontab_SOURCES, crontab_CPPFLAGS, crontab_DEPENDENCIES)
(mcron_CPPFLAGS, mcronscriptdir, dist_mcronscript_DATA): New variables.
(modules): Redefine it in terms of other '_DATA' variables.
* src/mcron/crontab.scm: Remove file.
* src/mcron/main.scm (parse-args): New procedure.
(command-name, command-type, options): Remove.
(show-version): Adapt.
(show-help, process-files-in-system-directory, cron-file-descriptors)
(main, process-user-file, process-files-in-user-directory): Move
procedures in the new files.
* src/mcron.c (inner_main): Define the current module at compile time.
* TODO: Update.
* .gitignore: Likewise.

9 files changed, 589 insertions, 542 deletions

diff --git a/.gitignore b/.gitignore
index c064be1..d4fc72a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,8 @@
 /build-aux/mdate-sh
 /build-aux/missing
 /build-aux/texinfo.tex
+/cron
+/crontab
 /doc/config.texi
 /doc/mcron.1
 /doc/mcron.info
diff --git a/Makefile.am b/Makefile.am
index 8c105e9..dc47945 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -16,13 +16,25 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-bin_PROGRAMS = mcron
+bin_PROGRAMS = mcron crontab
+sbin_PROGRAMS = cron
+
+AM_CFLAGS = @GUILE_CFLAGS@
+LDADD = @GUILE_LIBS@
+
 mcron_SOURCES = src/mcron.c
-mcron_CFLAGS = @GUILE_CFLAGS@
-mcron_DEPENDENCIES = $(mcronmodule_DATA)
-mcron_LDADD = @GUILE_LIBS@
+mcron_CPPFLAGS = -DPROGRAM="\"mcron\""
+mcron_DEPENDENCIES = $(modules:%.scm=%.go)
 
-modules = \
+cron_SOURCES = src/mcron.c
+cron_CPPFLAGS = -DPROGRAM="\"cron\""
+cron_DEPENDENCIES = $(modules:%.scm=%.go)
+
+crontab_SOURCES = src/mcron.c
+crontab_CPPFLAGS = -DPROGRAM="\"crontab\""
+crontab_DEPENDENCIES = $(modules:%.scm=%.go)
+
+dist_mcronmodule_DATA = \
   src/mcron/base.scm \
   src/mcron/environment.scm \
   src/mcron/job-specifier.scm \
@@ -32,13 +44,22 @@ modules = \
   src/mcron/vixie-time.scm
 
 mcronmodule_DATA = \
-  $(modules:%.scm=%.go) \
+  $(dist_mcronmodule_DATA:%.scm=%.go) \
   src/mcron/config.scm \
   src/mcron/config.go
 
-dist_mcronmodule_DATA = \
-  $(modules) \
-  src/mcron/crontab.scm
+mcronscriptdir = $(mcronmoduledir)/scripts
+dist_mcronscript_DATA = \
+  src/mcron/scripts/cron.scm \
+  src/mcron/scripts/crontab.scm \
+  src/mcron/scripts/mcron.scm
+
+mcronscript_DATA = $(dist_mcronscript_DATA:%.scm=%.go)
+
+modules = \
+  $(dist_mcronmodule_DATA) \
+  $(dist_mcronscript_DATA) \
+  src/mcron/config.scm
 
 # Unset 'GUILE_LOAD_COMPILED_PATH' altogether while compiling.  Otherwise, if
 # $GUILE_LOAD_COMPILED_PATH contains $(mcronmoduledir), we may find .go files
diff --git a/TODO b/TODO
index b43f233..2b7329f 100644
--- a/TODO
+++ b/TODO
@@ -20,9 +20,6 @@ Maybe in the near future...
        core or other users' files up. Then allow scheme code in the system
        crontabs.
               
-    * Make mcron behavior not depend on the name used to invoke it, to conform
-      to GNU Coding Standards.
-
     * Provide a test suite using SRFI-64 API.
       <http://srfi.schemers.org/srfi-64/srfi-64.html>.
 
diff --git a/src/mcron.c b/src/mcron.c
index 92e1a37..026b077 100644
--- a/src/mcron.c
+++ b/src/mcron.c
@@ -53,7 +53,7 @@ inner_main (void *closure, int argc, char **argv)
       scm_c_eval_string ("(set! %load-compiled-path (cons \""
                          PACKAGE_LOAD_PATH "\" %load-compiled-path))");
     }
-  scm_set_current_module (scm_c_resolve_module ("mcron main"));
+  scm_set_current_module (scm_c_resolve_module ("mcron scripts " PROGRAM));
   /* Register set_cron_signals to be called from Guile.  */
   scm_c_define_gsubr ("c-set-cron-signals", 0, 0, 0, set_cron_signals);
   scm_c_eval_string ("(main)");
diff --git a/src/mcron/crontab.scm b/src/mcron/crontab.scm
deleted file mode 100644
index 6be5c61..0000000
--- a/src/mcron/crontab.scm
+++ /dev/null
@@ -1,228 +0,0 @@
-;;   Copyright (C) 2003, 2014 Dale Mellor
-;; 
-;;   This file is part of GNU mcron.
-;;
-;;   GNU mcron 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 3 of the License, or (at your option)
-;;   any later version.
-;;
-;;   GNU mcron 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 GNU mcron.  If not, see <http://www.gnu.org/licenses/>.
-
-
-;; Apart from the collecting of options and the handling of --help and --version
-;; (which are done in the main.scm file), this file provides all the
-;; functionality of the crontab personality. It is designed to be loaded and run
-;; once, and then the calling program can exit and the crontab program will have
-;; completed its function.
-
-
-
-;; Procedure to communicate with running cron daemon that a user has modified
-;; his crontab. The user name is written to the /var/cron/socket UNIX socket.
-
-(let ((hit-server
-       (lambda (user-name)
-         (catch #t (lambda ()
-                     (let ((socket (socket AF_UNIX SOCK_STREAM 0)))
-                       (connect socket AF_UNIX config-socket-file)
-                       (display user-name socket)
-                       (close socket)))
-                (lambda (key . args)
-                  (display "Warning: a cron daemon is not running.\n")))))
-
-
-
-;; Procedure to scan a file containing one user name per line (such as
-;; /var/cron/allow and /var/cron/deny), and determine if the given name is in
-;; there. The procedure returns #t, #f, or '() if the file does not exist.
-
-      (in-access-file?
-       (lambda (file name)
-         (catch #t (lambda ()
-                     (with-input-from-file
-                         file
-                       (lambda ()
-                         (let loop ((input (read-line)))
-                           (if (eof-object? input)
-                               #f
-                               (if (string=? input name)
-                                   #t
-                                   (loop (read-line))))))))
-                (lambda (key . args) '()))))
-      
-      
-
-      ;; This program should have been installed SUID root. Here we get the
-      ;; passwd entry for the real user who is running this program.
-
-      (crontab-real-user (passwd:name (getpw (getuid)))))
-
-
-
-  ;; If the real user is not allowed to use crontab due to the /var/cron/allow
-  ;; and/or /var/cron/deny files, bomb out now.
-
-  (if (or (eq? (in-access-file? config-allow-file crontab-real-user) #f)
-          (eq? (in-access-file? config-deny-file crontab-real-user) #t))
-      (mcron-error 6 "Access denied by system operator."))
-  
-
-
-  ;; Check that no more than one of the mutually exclusive options are being
-  ;; used.
-
-  (if (> (+ (if (option-ref options 'edit #f) 1 0)
-            (if (option-ref options 'list #f) 1 0)
-            (if (option-ref options 'remove #f) 1 0))
-         1)
-      (mcron-error 7 "Only one of options -e, -l or -r can be used."))
-
-
-
-  ;; Check that a non-root user is trying to read someone else's files.
-
-  (if (and (not (eqv? (getuid) 0))
-           (option-ref options 'user #f))
-      (mcron-error 8 "Only root can use the -u option."))
-
-
-
-  (let (
-
-  
-        ;; Iff the --user option is given, the crontab-user may be different
-        ;; from the real user.
-
-        (crontab-user (option-ref options 'user crontab-real-user))
-
-
-        ;; So now we know which crontab file we will be manipulating.
-        
-        (crontab-file (string-append config-spool-dir "/" crontab-user))
-
-
-
-        ;; Display the prompt and wait for user to type his choice. Return #t if
-        ;; the answer begins with 'y' or 'Y', return #f if it begins with 'n' or
-        ;; 'N', otherwise ask again.
-
-        (get-yes-no (lambda (prompt . re-prompt)
-                      (if (not (null? re-prompt))
-                          (display "Please answer y or n.\n"))
-                      (display (string-append prompt " "))
-                      (let ((r (read-line)))
-                        (if (not (string-null? r))
-                            (case (string-ref r 0)
-                              ((#\y #\Y) #t)
-                              ((#\n #\N) #f)
-                              (else (get-yes-no prompt #t)))
-                            (get-yes-no prompt #t))))))
-
-
-
-    ;; There are four possible sub-personalities to the crontab personality:
-    ;; list, remove, edit and replace (when the user uses no options but
-    ;; supplies file names on the command line).
-
-    (cond
-
-
- ;; In the list personality, we simply open the crontab and copy it
- ;; character-by-character to the standard output. If anything goes wrong, it
- ;; can only mean that this user does not have a crontab file.
- 
- ((option-ref options 'list #f)
-  (catch #t (lambda ()
-              (with-input-from-file crontab-file (lambda ()
-                 (do ((input (read-char) (read-char)))
-                     ((eof-object? input))
-                   (display input)))))
-         (lambda (key . args)
-           (display (string-append "No crontab for "
-                                   crontab-user
-                                   " exists.\n")))))
-
-
- ;; In the edit personality, we determine the name of a temporary file and an
- ;; editor command, copy an existing crontab file (if it is there) to the
- ;; temporary file, making sure the ownership is set so the real user can edit
- ;; it; once the editor returns we try to read the file to check that it is
- ;; parseable (but do nothing more with the configuration), and if it is okay
- ;; (this program is still running!) we move the temporary file to the real
- ;; crontab, wake the cron daemon up, and remove the temporary file. If the
- ;; parse fails, we give user a choice of editing the file again or quitting
- ;; the program and losing all changes made.
-
- ((option-ref options 'edit #f)
-  (let ((temp-file (string-append config-tmp-dir
-                                  "/crontab."
-                                  (number->string (getpid)))))
-    (catch #t (lambda () (copy-file crontab-file temp-file))
-              (lambda (key . args) (with-output-to-file temp-file noop)))
-    (chown temp-file (getuid) (getgid))
-    (let retry ()
-      (system (string-append
-               (or (getenv "VISUAL") (getenv "EDITOR") "vi")
-               " "
-               temp-file))
-      (catch 'mcron-error
-             (lambda () (read-vixie-file temp-file))
-             (lambda (key exit-code . msg)
-               (apply mcron-error 0 msg)
-               (if (get-yes-no "Edit again?")
-                   (retry)
-                   (begin
-                     (mcron-error 0 "Crontab not changed")
-                     (primitive-exit 0))))))
-    (copy-file temp-file crontab-file)
-    (delete-file temp-file)
-    (hit-server crontab-user)))
-
-
- ;; In the remove personality we simply make an effort to delete the crontab and
- ;; wake the daemon. No worries if this fails.
-
- ((option-ref options 'remove #f)
-  (catch #t (lambda () (delete-file crontab-file)
-                       (hit-server crontab-user))
-            noop))
-
-
- ;; !!!!  This comment is wrong.
- 
- ;; In the case of the replace personality we loop over all the arguments on the
- ;; command line, and for each one parse the file to make sure it is parseable
- ;; (but subsequently ignore the configuration), and all being well we copy it
- ;; to the crontab location; we deal with the standard input in the same way but
- ;; different. :-)  In either case the server is woken so that it will read the
- ;; newly installed crontab.
-
- ((not (null? (option-ref options '() '())))
-  (let ((input-file (car (option-ref options '() '()))))
-    (catch-mcron-error
-     (if (string=? input-file "-")
-         (let ((input-string (stdin->string)))
-           (read-vixie-port (open-input-string input-string))
-           (with-output-to-file crontab-file (lambda ()
-                                               (display input-string))))
-         (begin
-           (read-vixie-file input-file)
-           (copy-file input-file crontab-file))))
-    (hit-server crontab-user)))
- 
- 
- ;; The user is being silly. The message here is identical to the one Vixie cron
- ;; used to put out, for total compatibility.
-
- (else (mcron-error 15
-         "usage error: file name must be specified for replace.")))
-
-
-)) ;; End of file-level let-scopes.
diff --git a/src/mcron/main.scm b/src/mcron/main.scm
index db7dfd6..1faa1ae 100644
--- a/src/mcron/main.scm
+++ b/src/mcron/main.scm
@@ -16,30 +16,22 @@
 ;;   You should have received a copy of the GNU General Public License along
 ;;   with GNU mcron.  If not, see <http://www.gnu.org/licenses/>.
 
-;;; This is the 'main' routine for the whole system; this module is the global
-;;; entry point (after the minimal C wrapper); to all intents and purposes the
-;;; program is pure Guile and starts here.
-
 (define-module (mcron main)
   #:use-module (ice-9 getopt-long)
   #:use-module (ice-9 rdelim)
-  #:use-module (ice-9 regex)
   #:use-module (mcron config)
   #:use-module (mcron base)
   #:use-module (mcron job-specifier)
   #:use-module (mcron vixie-specification)
-  #:use-module (srfi srfi-2)
-  #:use-module (srfi srfi-26)
-  #:export (delete-run-file
-	    main))
-
-(define* (command-name #:optional (command (car (command-line))))
-  "Extract the actual command name from COMMAND.  This returns the last part
-of COMMAND without any non-alphabetic characters.  For example \"in.cron\" and
-\"./mcron\" will return respectively \"cron\" and \"mcron\".
-
-When COMMAND is not specified this uses the first element of (command-line)."
-  (match:substring (regexp-exec (make-regexp "[[:alpha:]]*$") command)))
+  #:export (catch-mcron-error
+            mcron-error
+            parse-args
+            show-version
+            show-package-information
+            stdin->string
+            for-each-file
+            process-update-request)
+  #:re-export (option-ref))
 
 (define (mcron-error exit-code . rest)
   "Print an error message (made up from the parts of REST), and if the
@@ -47,7 +39,7 @@ EXIT-CODE error is fatal (present and non-zero) then exit to the system with
 EXIT-CODE."
   (with-output-to-port (current-error-port)
     (lambda ()
-      (for-each display (append (list (command-name) ": ") rest))
+      (for-each display (cons "mcron: " rest))
       (newline)))
   (when (and exit-code (not (eq? exit-code 0)))
     (primitive-exit exit-code)))
@@ -60,48 +52,14 @@ and exit with its error code."
     (lambda (key exit-code . msg)
       (apply mcron-error exit-code msg))))
 
-(define command-type
-  ;; We will be doing a lot of testing of the command name, so it makes sense
-  ;; to perform the string comparisons once and for all here.
-  (let* ((command   (command-name))
-         (command=? (cut string=? command <>)))
-    (cond ((command=? "mcron") 'mcron)
-          ((or (command=? "cron") (command=? "crond")) 'cron)
-          ((command=? "crontab") 'crontab)
-          (else (mcron-error 12 "The command name is invalid.")))))
+(define (parse-args args option-desc-list)
+  "Parse ARGS with OPTION-DESC-LIST specification."
+  (catch 'misc-error
+    (lambda () (getopt-long args option-desc-list))
+    (lambda (key func fmt args . rest)
+      (mcron-error 1 (apply format (append (list #f fmt) args))))))
 
-(define options
-  ;; There are a different set of options for the crontab personality compared
-  ;; to all the others, with the --help and --version options common to all
-  ;; the personalities.
-  (catch
-   'misc-error
-   (lambda ()
-     (getopt-long (command-line)
-                  (append
-                   (case command-type
-                     ((crontab)
-                      '((user     (single-char #\u) (value #t))
-                        (edit     (single-char #\e) (value #f))
-                        (list     (single-char #\l) (value #f))
-                        (remove   (single-char #\r) (value #f))))
-                     (else `((schedule (single-char #\s) (value #t)
-                                       (predicate
-                                        ,(lambda (value)
-                                           (string->number value))))
-                             (daemon   (single-char #\d) (value #f))
-                             (noetc    (single-char #\n) (value #f))
-                             (stdin    (single-char #\i) (value #t)
-                                       (predicate
-                                        ,(lambda (value)
-                                           (or (string=? "vixie" value)
-                                               (string=? "guile" value))))))))
-                   '((version  (single-char #\v) (value #f))
-                     (help     (single-char #\h) (value #f))))))
-   (lambda (key func fmt args . rest)
-     (mcron-error 1 (apply format (append (list #f fmt) args))))))
-
-(define* (show-version #:optional (command (command-name)))
+(define (show-version command)
   "Display version information for COMMAND and quit."
   (let* ((name       config-package-name)
          (short-name (cadr (string-split name #\space)))
@@ -111,8 +69,7 @@ Copyright (C) 2015 the ~a authors.
 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.\n"
-		   command name version short-name)
-    (quit)))
+		   command name version short-name)))
 
 (define (show-package-information)
   "Display where to get help and send bug reports."
@@ -123,56 +80,6 @@ General help using GNU software: <http://www.gnu.org/gethelp/>\n"
 		 config-package-name
 		 config-package-url))
 
-(define* (show-help #:optional (command (command-name)))
-  "Display informations of usage for COMMAND and quit."
-  (simple-format #t "Usage: ~a" command)
-  (display
-   (case command-type
-     ((mcron)
-      " [OPTIONS] [FILES]
-Run an mcron process according to the specifications in the FILES (`-' for
-standard input), or use all the files in ~/.config/cron (or the
-deprecated ~/.cron) with .guile or .vixie extensions.
-
-  -v, --version             Display version
-  -h, --help                Display this help message
-  -sN, --schedule[=]N       Display the next N jobs that will be run by mcron
-  -d, --daemon              Immediately detach the program from the terminal
-                              and run as a daemon process
-  -i, --stdin=(guile|vixie) Format of data passed as standard input or
-                              file arguments (default guile)")
-     ((cron)
-      " [OPTIONS]
-Unless an option is specified, run a cron daemon as a detached process,
-reading all the information in the users' crontabs and in /etc/crontab.
-
-  -v, --version             Display version
-  -h, --help                Display this help message
-  -sN, --schedule[=]N       Display the next N jobs that will be run by cron
-  -n, --noetc               Do not check /etc/crontab for updates (HIGHLY
-                              RECOMMENDED).")
-     ((crontab)
-      " [-u user] file
-       crontab [-u user] { -e | -l | -r }
-               (default operation is replace, per 1003.2)
-       -e      (edit user's crontab)
-       -l      (list user's crontab)
-       -r      (delete user's crontab")
-     (else "\nrubbish")))
-  (newline)
-  (show-package-information)
-  (quit))
-
-(define (delete-run-file)
-  "Remove the /var/run/cron.pid file so that crontab and other invocations of
-cron don't get the wrong idea that a daemon is currently running.  This
-procedure is called from the C front-end whenever a terminal signal is
-received."
-  (catch #t (lambda () (delete-file config-pid-file)
-                       (delete-file config-socket-file))
-            noop)
-  (quit))
-
 (define (stdin->string)
   "Return standard input as a string."
   (with-output-to-string (lambda () (do ((in (read-char) (read-char)))
@@ -188,83 +95,6 @@ is not specified"
         ((eof-object? file-name) (closedir dir))
       (proc file-name))))
 
-(define process-user-file
-  (let ((guile-regexp (make-regexp "\\.gui(le)?$"))
-        (vixie-regexp (make-regexp "\\.vix(ie)?$")))
-    (lambda* (file-name #:optional guile-syntax?)
-      "Process FILE-NAME according its extension.  When GUILE-SYNTAX? is TRUE,
-force guile syntax usage.  If FILE-NAME format is not recognized, it is
-silently ignored."
-      (cond ((string=? "-" file-name)
-             (if (string=? (option-ref options 'stdin "guile") "vixie")
-                 (read-vixie-port (current-input-port))
-                 (eval-string (stdin->string))))
-            ((or guile-syntax? (regexp-exec guile-regexp file-name))
-             (load file-name))
-            ((regexp-exec vixie-regexp file-name)
-             (read-vixie-file file-name))))))
-
-(define (process-files-in-user-directory)
-  "Process files in $XDG_CONFIG_HOME/cron and/or ~/.cron directories (if
-$XDG_CONFIG_HOME is not defined uses ~/.config/cron instead)."
-  (let ((errors 0)
-        (home-directory (passwd:dir (getpw (getuid)))))
-    (map (lambda (dir)
-           (catch #t
-             (lambda ()
-               (for-each-file
-                (lambda (file)
-                  (process-user-file (string-append dir "/" file)))
-                dir))
-             (lambda (key . args)
-               (set! errors (1+ errors)))))
-         (list (string-append home-directory "/.cron")
-               (string-append (or (getenv "XDG_CONFIG_HOME")
-                                  (string-append home-directory "/.config"))
-                              "/cron")))
-    (when (eq? 2 errors)
-      (mcron-error 13
-        "Cannot read files in your ~/.config/cron (or ~/.cron) directory."))))
-
-(define (process-files-in-system-directory)
-  "Process all the files in the crontab directory.  When the job procedure is
-run on behalf of the configuration files, the jobs are registered on the
-system with the appropriate user.  Only root should be able to perform this
-operation.  The permissions on the /var/cron/tabs directory enforce this."
-
-  (define (user-entry name)
-    ;; Return the user database entry if NAME is valid, otherwise #f.
-    (false-if-exception (getpwnam name)))
-
-  (catch #t
-    (lambda ()
-      (for-each-file
-       (lambda (user)
-         (and-let* ((entry (user-entry user))) ;crontab without user?
-           (set-configuration-user entry)
-           (catch-mcron-error
-            (read-vixie-file (string-append config-spool-dir "/" user)))))
-       config-spool-dir))
-    (lambda (key . args)
-      (mcron-error 4
-        "You do not have permission to access the system crontabs."))))
-
-(define (cron-file-descriptors)
-  "Establish a socket to listen for updates from a crontab program, and return
-a list containing the file descriptors correponding to the files read by
-crontab.  This requires that command-type is 'cron."
-  (if (eq? command-type 'cron)
-      (catch #t
-	(lambda ()
-	  (let ((sock (socket AF_UNIX SOCK_STREAM 0)))
-	    (bind sock AF_UNIX config-socket-file)
-	    (listen sock 5)
-	    (list sock)))
-	(lambda (key . args)
-	  (delete-file config-pid-file)
-	  (mcron-error 1 "Cannot bind to UNIX socket " config-socket-file)))
-      '()))
-
 (define (process-update-request fdes-list)
   "Read a user name from the socket, dealing with the /etc/crontab special
 case, remove all the user's jobs from the job list, and then re-read the
@@ -286,116 +116,3 @@ comes in on the above socket."
            (remove-user-jobs user)
            (set-configuration-user user)
            (read-vixie-file (string-append config-spool-dir "/" user-name)))))))
-
-
-;;;
-;;; Entry point.
-;;;
-
-(define (main . args)
-  ;; Turn debugging on if indicated.
-  (when config-debug
-    (debug-enable 'backtrace))
-  (when (option-ref options 'version #f)
-    (show-version))
-  (when (option-ref options 'help #f)
-    (show-help))
-
-  ;; Setup the cron process, if appropriate. If there is already a
-  ;; /var/run/cron.pid file, then we must assume a cron daemon is already
-  ;; running and refuse to start another one.
-  ;;
-  ;; Otherwise, clear the MAILTO environment variable so that output from cron
-  ;; jobs is sent to the various users (this may still be overridden in the
-  ;; configuration files), and call the function in the C wrapper to set up
-  ;; terminal signal responses to vector to the procedure above. The PID file
-  ;; will be filled in properly later when we have forked our daemon process
-  ;; (but not done if we are only viewing the schedules).
-  (when (eq? command-type 'cron)
-    (unless (eqv? (getuid) 0)
-      (mcron-error 16
-        "This program must be run by the root user (and should have been "
-        "installed as such)."))
-    (when (access? config-pid-file F_OK)
-      (mcron-error 1
-        "A cron daemon is already running.\n  (If you are sure this is not"
-        " true, remove the file\n   " config-pid-file ".)"))
-    (unless (option-ref options 'schedule #f)
-      (with-output-to-file config-pid-file noop))
-    (setenv "MAILTO" #f)
-    ;; XXX: At compile time, this yields a "possibly unbound variable"
-    ;; warning, but this is OK since it is bound in the C wrapper.
-    (c-set-cron-signals))
-
-  ;; Now we have the procedures in place for dealing with the contents of
-  ;; configuration files, the crontab personality is able to validate such
-  ;; files. If the user requested the crontab personality, we load and run the
-  ;; code here and then get out.
-  (when (eq? command-type 'crontab)
-    (load "crontab.scm")
-    (quit))
-
-  ;; Having defined all the necessary procedures for scanning various sets of
-  ;; files, we perform the actual configuration of the program depending on
-  ;; the personality we are running as. If it is mcron, we either scan the
-  ;; files passed on the command line, or else all the ones in the user's
-  ;; .config/cron (or .cron) directory. If we are running under the cron
-  ;; personality, we read the /var/cron/tabs directory and also the
-  ;; /etc/crontab file.
-  (case command-type
-    ((mcron)
-     (if (null? (option-ref options '() '()))
-         (process-files-in-user-directory)
-         (for-each (lambda (file-path) (process-user-file file-path #t))
-                   (option-ref options '() '()))))
-    ((cron)
-     (process-files-in-system-directory)
-     (use-system-job-list)
-     (catch-mcron-error (read-vixie-file "/etc/crontab"
-                                         parse-system-vixie-line))
-     (use-user-job-list)
-     (unless (option-ref options 'noetc #f)
-       (display "\
-WARNING: cron will check for updates to /etc/crontab EVERY MINUTE. If you do
-not use this file, or you are prepared to manually restart cron whenever you
-make a change, then it is HIGHLY RECOMMENDED that you use the --noetc
-option.\n")
-       (set-configuration-user "root")
-       (job '(- (next-minute-from (next-minute)) 6)
-            check-system-crontab
-            "/etc/crontab update checker."))))
-
-  ;; If the user has requested a schedule of jobs that will run, we provide
-  ;; the information here and then get out.  Start by determining the number
-  ;; of time points in the future that output is required for. This may be
-  ;; provided on the command line as a parameter to the --schedule option, or
-  ;; else we assume a default of 8. Finally, ensure that the count is some
-  ;; positive integer.
-  (and-let* ((count (option-ref options 'schedule #f)))
-            (set! count (string->number count))
-            (display (get-schedule (if (<= count 0) 1 count)))
-            (quit))
-
-  ;; If we are supposed to run as a daemon process (either a --daemon option
-  ;; has been explicitly used, or we are running as cron or crond), detach
-  ;; from the terminal now. If we are running as cron, we can now write the
-  ;; PID file.
-  (when (option-ref options 'daemon (eq? command-type 'cron))
-    (unless (eqv? (primitive-fork) 0)
-      (quit))
-    (setsid)
-    (when (eq? command-type 'cron)
-      (with-output-to-file config-pid-file
-        (lambda () (display (getpid)) (newline)))))
-
-  ;; Now the main loop. Forever execute the run-job-loop procedure in the
-  ;; mcron base, and when it drops out (can only be because a message has come
-  ;; in on the socket) we process the socket request before restarting the
-  ;; loop again.  Sergey Poznyakoff: we can also drop out of run-job-loop
-  ;; because of a SIGCHLD, so must test FDES-LIST.
-  (catch-mcron-error
-   (let ((fdes-list (cron-file-descriptors)))
-     (while #t
-       (run-job-loop fdes-list)
-       (unless (null? fdes-list)
-         (process-update-request fdes-list))))))
diff --git a/src/mcron/scripts/cron.scm b/src/mcron/scripts/cron.scm
new file mode 100644
index 0000000..dd8f5ad
--- /dev/null
+++ b/src/mcron/scripts/cron.scm
@@ -0,0 +1,177 @@
+;;;; cron -- daemon for running jobs at scheduled times
+;;; Copyright © 2003, 2012 Dale Mellor <dale_mellor@users.sourceforge.net>
+;;; Copyright © 2015, 2016 Mathieu Lirzin <mthl@gnu.org>
+;;;
+;;; This file is part of GNU Mcron.
+;;;
+;;; GNU Mcron 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 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; GNU Mcron 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 GNU Mcron.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (mcron scripts cron)
+  #:use-module (mcron base)
+  #:use-module (mcron config)
+  #:use-module (mcron job-specifier)
+  #:use-module (mcron main)
+  #:use-module (mcron vixie-specification)
+  #:use-module (srfi srfi-2)
+  #:export (main))
+
+(define (show-help)
+  (display "Usage: cron [OPTIONS]
+Unless an option is specified, run a cron daemon as a detached process,
+reading all the information in the users' crontabs and in /etc/crontab.
+
+  -v, --version             Display version
+  -h, --help                Display this help message
+  -sN, --schedule[=]N       Display the next N jobs that will be run by cron
+  -n, --noetc               Do not check /etc/crontab for updates (HIGHLY
+                              RECOMMENDED).")
+  (newline)
+  (show-package-information))
+
+(define %options
+  `((schedule (single-char #\s) (value #t)
+              (predicate ,(λ (str) (string->number str))))
+    (noetc    (single-char #\n) (value #f))
+    (version  (single-char #\v) (value #f))
+    (help     (single-char #\h) (value #f))))
+
+(define (delete-run-file)
+  "Remove the /var/run/cron.pid file so that crontab and other invocations of
+cron don't get the wrong idea that a daemon is currently running.  This
+procedure is called from the C front-end whenever a terminal signal is
+received."
+  (catch #t
+    (λ ()
+      (delete-file config-pid-file)
+      (delete-file config-socket-file))
+    noop)
+  (quit))
+
+(define (cron-file-descriptors)
+  "Establish a socket to listen for updates from a crontab program, and return
+a list containing the file descriptors correponding to the files read by
+crontab.  This requires that command-type is 'cron."
+  (catch #t
+    (λ ()
+      (let ((sock (socket AF_UNIX SOCK_STREAM 0)))
+        (bind sock AF_UNIX config-socket-file)
+        (listen sock 5)
+        (list sock)))
+    (λ (key . args)
+      (delete-file config-pid-file)
+      (mcron-error 1 "Cannot bind to UNIX socket " config-socket-file))))
+
+(define (process-files-in-system-directory)
+  "Process all the files in the crontab directory.  When the job procedure is
+run on behalf of the configuration files, the jobs are registered on the
+system with the appropriate user.  Only root should be able to perform this
+operation.  The permissions on the /var/cron/tabs directory enforce this."
+
+  (define (user-entry name)
+    ;; Return the user database entry if NAME is valid, otherwise #f.
+    (false-if-exception (getpwnam name)))
+
+  (catch #t
+    (λ ()
+      (for-each-file
+       (λ (user)
+         (and-let* ((entry (user-entry user))) ;crontab without user?
+           (set-configuration-user entry)
+           (catch-mcron-error
+            (read-vixie-file (string-append config-spool-dir "/" user)))))
+       config-spool-dir))
+    (λ (key . args)
+      (mcron-error 4
+        "You do not have permission to access the system crontabs."))))
+
+(define (%process-files schedule? noetc?)
+  ;; XXX: What is this supposed to do?
+  (when schedule?
+    (with-output-to-file config-pid-file noop))
+  ;; Clear MAILTO so that outputs are sent to the various users.
+  (setenv "MAILTO" #f)
+  ;; XXX: At compile time, this yields a "possibly unbound variable" warning,
+  ;; but this is OK since it is bound in the C wrapper.
+  (c-set-cron-signals)
+  ;; Having defined all the necessary procedures for scanning various sets of
+  ;; files, we perform the actual configuration of the program depending on
+  ;; the personality we are running as. If it is mcron, we either scan the
+  ;; files passed on the command line, or else all the ones in the user's
+  ;; .config/cron (or .cron) directory. If we are running under the cron
+  ;; personality, we read the /var/cron/tabs directory and also the
+  ;; /etc/crontab file.
+  (process-files-in-system-directory)
+  (use-system-job-list)
+  (catch-mcron-error
+   (read-vixie-file "/etc/crontab" parse-system-vixie-line))
+  (use-user-job-list)
+  (unless noetc?
+    (display "\
+WARNING: cron will check for updates to /etc/crontab EVERY MINUTE. If you do
+not use this file, or you are prepared to manually restart cron whenever you
+make a change, then it is HIGHLY RECOMMENDED that you use the --noetc
+option.\n")
+    (set-configuration-user "root")
+    (job '(- (next-minute-from (next-minute)) 6)
+         check-system-crontab
+         "/etc/crontab update checker.")))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define* (main #:optional (args (command-line)))
+  (let ((opts (parse-args args %options)))
+    (when config-debug
+      (debug-enable 'backtrace))
+    (cond
+     ((option-ref opts 'help #f)
+      (show-help)
+      (exit 0))
+     ((option-ref opts 'version #f)
+      (show-version "cron")
+      (exit 0))
+     ((not (zero? (getuid)))
+      (mcron-error 16
+        "This program must be run by the root user (and should"
+        " have been installed as such)."))
+     ((access? config-pid-file F_OK)
+      (mcron-error 1
+        "A cron daemon is already running.\n  (If you are sure"
+        " this is not true, remove the file\n   "
+        config-pid-file ".)"))
+     (else
+      (%process-files (option-ref opts 'schedule #f)
+                      (option-ref opts 'noetc #f))
+      (cond ((option-ref opts 'schedule #f) ;display jobs schedule
+             => (λ (count)
+                  (display (get-schedule (max 1 (string->number count))))
+                  (exit 0)))
+            (else (case (primitive-fork) ;run the daemon
+                    ((0)
+                     (setsid)
+                     ;; we can now write the PID file.
+                     (with-output-to-file config-pid-file
+                       (λ () (display (getpid)) (newline))))
+                    (else (exit 0)))))
+      ;; Forever execute the 'run-job-loop', and when it drops out (can
+      ;; only be because a message has come in on the socket) we
+      ;; process the socket request before restarting the loop again.
+      (catch-mcron-error
+       (let ((fdes-list (cron-file-descriptors)))
+         (while #t
+           (run-job-loop fdes-list)
+           (unless (null? fdes-list)
+             (process-update-request fdes-list)))))))))
diff --git a/src/mcron/scripts/crontab.scm b/src/mcron/scripts/crontab.scm
new file mode 100644
index 0000000..43ae8f6
--- /dev/null
+++ b/src/mcron/scripts/crontab.scm
@@ -0,0 +1,225 @@
+;;;; crontab -- edit user's cron tabs
+;;; Copyright © 2003, 2004 Dale Mellor <dale_mellor@users.sourceforge.net>
+;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
+;;;
+;;; This file is part of GNU Mcron.
+;;;
+;;; GNU Mcron 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 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; GNU Mcron 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 GNU Mcron.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (mcron scripts crontab)
+  #:use-module (ice-9 rdelim)
+  #:use-module (mcron config)
+  #:use-module (mcron main)
+  #:use-module (mcron vixie-specification)
+  #:export (main))
+
+(define* (show-help)
+  (display "Usage: crontab [-u user] file
+       crontab [-u user] { -e | -l | -r }
+               (default operation is replace, per 1003.2)
+       -e      (edit user's crontab)
+       -l      (list user's crontab)
+       -r      (delete user's crontab")
+  (newline)
+  (show-package-information))
+
+(define %options
+  '((user     (single-char #\u) (value #t))
+    (edit     (single-char #\e) (value #f))
+    (list     (single-char #\l) (value #f))
+    (remove   (single-char #\r) (value #f))
+    (version  (single-char #\v) (value #f))
+    (help     (single-char #\h) (value #f))))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define* (main #:optional (args (command-line)))
+  (let ((opts (parse-args args %options)))
+    (when config-debug
+      (debug-enable 'backtrace))
+    (cond ((option-ref opts 'help #f)
+           (show-help)
+           (exit 0))
+          ((option-ref opts 'version #f)
+           (show-version "crontab")
+           (exit 0)))
+    (let ((hit-server
+           (λ (user-name)
+             ;; Procedure to communicate with running cron daemon that a user
+             ;; has modified his crontab. The user name is written to the
+             ;; /var/cron/socket UNIX socket.
+             (catch #t
+               (λ ()
+                 (let ((socket (socket AF_UNIX SOCK_STREAM 0)))
+                   (connect socket AF_UNIX config-socket-file)
+                   (display user-name socket)
+                   (close socket)))
+               (λ (key . args)
+                 (display "Warning: a cron daemon is not running.\n")))))
+
+          ;; Procedure to scan a file containing one user name per line (such
+          ;; as /var/cron/allow and /var/cron/deny), and determine if the
+          ;; given name is in there. The procedure returns #t, #f, or '() if
+          ;; the file does not exist.
+          (in-access-file?
+           (λ (file name)
+             (catch #t
+               (λ ()
+                 (with-input-from-file file
+                   (λ ()
+                     (let loop ((input (read-line)))
+                       (if (eof-object? input)
+                           #f
+                           (if (string=? input name)
+                               #t
+                               (loop (read-line))))))))
+               (λ (key . args) '()))))
+
+          ;; This program should have been installed SUID root. Here we get
+          ;; the passwd entry for the real user who is running this program.
+          (crontab-real-user (passwd:name (getpw (getuid)))))
+
+      ;; If the real user is not allowed to use crontab due to the
+      ;; /var/cron/allow and/or /var/cron/deny files, bomb out now.
+      (if (or (eq? (in-access-file? config-allow-file crontab-real-user) #f)
+              (eq? (in-access-file? config-deny-file crontab-real-user) #t))
+          (mcron-error 6 "Access denied by system operator."))
+
+      ;; Check that no more than one of the mutually exclusive options are
+      ;; being used.
+      (when (> (+ (if (option-ref opts 'edit #f) 1 0)
+                  (if (option-ref opts 'list #f) 1 0)
+                  (if (option-ref opts 'remove #f) 1 0))
+               1)
+        (mcron-error 7 "Only one of options -e, -l or -r can be used."))
+
+      ;; Check that a non-root user is trying to read someone else's files.
+      (when (and (not (zero? (getuid)))
+                 (option-ref opts 'user #f))
+        (mcron-error 8 "Only root can use the -u option."))
+
+      (letrec* (;; Iff the --user option is given, the crontab-user may be
+                ;; different from the real user.
+                (crontab-user (option-ref opts 'user crontab-real-user))
+                ;; So now we know which crontab file we will be manipulating.
+                (crontab-file (string-append config-spool-dir "/" crontab-user))
+                ;; Display the prompt and wait for user to type his
+                ;; choice. Return #t if the answer begins with 'y' or 'Y',
+                ;; return #f if it begins with 'n' or 'N', otherwise ask
+                ;; again.
+                (get-yes-no (λ (prompt . re-prompt)
+                              (if (not (null? re-prompt))
+                                  (display "Please answer y or n.\n"))
+                              (display (string-append prompt " "))
+                              (let ((r (read-line)))
+                                (if (not (string-null? r))
+                                    (case (string-ref r 0)
+                                      ((#\y #\Y) #t)
+                                      ((#\n #\N) #f)
+                                      (else (get-yes-no prompt #t)))
+                                    (get-yes-no prompt #t))))))
+        ;; There are four possible sub-personalities to the crontab
+        ;; personality: list, remove, edit and replace (when the user uses no
+        ;; options but supplies file names on the command line).
+        (cond
+         ;; In the list personality, we simply open the crontab and copy it
+         ;; character-by-character to the standard output. If anything goes
+         ;; wrong, it can only mean that this user does not have a crontab
+         ;; file.
+         ((option-ref opts 'list #f)
+          (catch #t
+            (λ ()
+              (with-input-from-file crontab-file
+                (λ ()
+                  (do ((input (read-char) (read-char)))
+                      ((eof-object? input))
+                    (display input)))))
+            (λ (key . args)
+              (display (string-append "No crontab for "
+                                      crontab-user
+                                      " exists.\n")))))
+
+         ;; In the edit personality, we determine the name of a temporary file
+         ;; and an editor command, copy an existing crontab file (if it is
+         ;; there) to the temporary file, making sure the ownership is set so
+         ;; the real user can edit it; once the editor returns we try to read
+         ;; the file to check that it is parseable (but do nothing more with
+         ;; the configuration), and if it is okay (this program is still
+         ;; running!) we move the temporary file to the real crontab, wake the
+         ;; cron daemon up, and remove the temporary file. If the parse fails,
+         ;; we give user a choice of editing the file again or quitting the
+         ;; program and losing all changes made.
+         ((option-ref opts 'edit #f)
+          (let ((temp-file (string-append config-tmp-dir
+                                          "/crontab."
+                                          (number->string (getpid)))))
+            (catch #t
+              (λ () (copy-file crontab-file temp-file))
+              (λ (key . args) (with-output-to-file temp-file noop)))
+            (chown temp-file (getuid) (getgid))
+            (let retry ()
+              (system (string-append
+                       (or (getenv "VISUAL") (getenv "EDITOR") "vi")
+                       " "
+                       temp-file))
+              (catch 'mcron-error
+                (λ () (read-vixie-file temp-file))
+                (λ (key exit-code . msg)
+                  (apply mcron-error 0 msg)
+                  (if (get-yes-no "Edit again?")
+                      (retry)
+                      (begin
+                        (mcron-error 0 "Crontab not changed")
+                        (primitive-exit 0))))))
+            (copy-file temp-file crontab-file)
+            (delete-file temp-file)
+            (hit-server crontab-user)))
+
+         ;; In the remove personality we simply make an effort to delete the
+         ;; crontab and wake the daemon. No worries if this fails.
+         ((option-ref opts 'remove #f)
+          (catch #t
+            (λ ()
+              (delete-file crontab-file)
+              (hit-server crontab-user))
+            noop))
+
+         ;; XXX: This comment is wrong.
+         ;; In the case of the replace personality we loop over all the
+         ;; arguments on the command line, and for each one parse the file to
+         ;; make sure it is parseable (but subsequently ignore the
+         ;; configuration), and all being well we copy it to the crontab
+         ;; location; we deal with the standard input in the same way but
+         ;; different. :-) In either case the server is woken so that it will
+         ;; read the newly installed crontab.
+         ((not (null? (option-ref opts '() '())))
+          (let ((input-file (car (option-ref opts '() '()))))
+            (catch-mcron-error
+             (if (string=? input-file "-")
+                 (let ((input-string (stdin->string)))
+                   (read-vixie-port (open-input-string input-string))
+                   (with-output-to-file crontab-file
+                     (λ () (display input-string))))
+                 (begin
+                   (read-vixie-file input-file)
+                   (copy-file input-file crontab-file))))
+            (hit-server crontab-user)))
+
+         ;; The user is being silly. The message here is identical to the one
+         ;; Vixie cron used to put out, for total compatibility.
+         (else (mcron-error 15
+                 "usage error: file name must be specified for replace.")))))))
diff --git a/src/mcron/scripts/mcron.scm b/src/mcron/scripts/mcron.scm
new file mode 100644
index 0000000..30b2d2a
--- /dev/null
+++ b/src/mcron/scripts/mcron.scm
@@ -0,0 +1,136 @@
+;;;; mcron -- run jobs at scheduled times
+;;; Copyright © 2003, 2012 Dale Mellor <dale_mellor@users.sourceforge.net>
+;;; Copyright © 2015, 2016 Mathieu Lirzin <mthl@gnu.org>
+;;;
+;;; This file is part of GNU Mcron.
+;;;
+;;; GNU Mcron 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 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; GNU Mcron 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 GNU Mcron.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (mcron scripts mcron)
+  #:use-module (mcron base)
+  #:use-module (mcron config)
+  #:use-module (mcron job-specifier)    ;for user/system files
+  #:use-module (mcron main)
+  #:use-module (mcron vixie-specification)
+  #:export (main))
+
+(define (show-help)
+  (display "Usage: mcron [OPTIONS] [FILES]
+Run an mcron process according to the specifications in the FILES (`-' for
+standard input), or use all the files in ~/.config/cron (or the
+deprecated ~/.cron) with .guile or .vixie extensions.
+
+  -v, --version             Display version
+  -h, --help                Display this help message
+  -sN, --schedule[=]N       Display the next N jobs that will be run by mcron
+  -d, --daemon              Immediately detach the program from the terminal
+                              and run as a daemon process
+  -i, --stdin=(guile|vixie) Format of data passed as standard input or
+                              file arguments (default guile)")
+  (newline)
+  (show-package-information))
+
+(define %options
+  `((schedule (single-char #\s) (value #t)
+              (predicate ,(λ (str) (string->number str))))
+    (daemon   (single-char #\d) (value #f))
+    (noetc    (single-char #\n) (value #f))
+    (stdin    (single-char #\i) (value #t)
+              (predicate ,(λ (val)
+                            (or (string=? val "guile")
+                                (string=? val "vixie")))))
+    (version  (single-char #\v) (value #f))
+    (help     (single-char #\h) (value #f))))
+
+(define process-user-file
+  (let ((guile-regexp (make-regexp "\\.gui(le)?$"))
+        (vixie-regexp (make-regexp "\\.vix(ie)?$")))
+    (lambda* (file-name #:optional guile-syntax? #:key (input "guile"))
+      "Process FILE-NAME according its extension.  When GUILE-SYNTAX? is TRUE,
+force guile syntax usage.  If FILE-NAME format is not recognized, it is
+silently ignored."
+      (cond ((string=? "-" file-name)
+             (if (string=? input "vixie")
+                 (read-vixie-port (current-input-port))
+                 (eval-string (stdin->string))))
+            ((or guile-syntax? (regexp-exec guile-regexp file-name))
+             (load file-name))
+            ((regexp-exec vixie-regexp file-name)
+             (read-vixie-file file-name))))))
+
+(define (process-files-in-user-directory input-type)
+  "Process files in $XDG_CONFIG_HOME/cron and/or ~/.cron directories (if
+$XDG_CONFIG_HOME is not defined uses ~/.config/cron instead)."
+  (let ((errors 0)
+        (home-directory (passwd:dir (getpw (getuid)))))
+    (map (λ (dir)
+           (catch #t
+             (λ ()
+               (for-each-file
+                (λ (file)
+                  (process-user-file (string-append dir "/" file)
+                                     #:input input-type))
+                dir))
+             (λ (key . args)
+               (set! errors (1+ errors)))))
+         (list (string-append home-directory "/.cron")
+               (string-append (or (getenv "XDG_CONFIG_HOME")
+                                  (string-append home-directory "/.config"))
+                              "/cron")))
+    (when (eq? 2 errors)
+      (mcron-error 13
+        "Cannot read files in your ~/.config/cron (or ~/.cron) directory."))))
+
+(define (%process-files files input-type)
+  (if (null? files)
+      (process-files-in-user-directory input-type)
+      (for-each (λ (file) (process-user-file file #t)) files)))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define* (main #:optional (args (command-line)))
+  (let ((opts (parse-args args %options)))
+    (when config-debug
+      (debug-enable 'backtrace))
+    (cond ((option-ref opts 'help #f)
+           (show-help)
+           (exit 0))
+          ((option-ref opts 'version #f)
+           (show-version "mcron")
+           (exit 0))
+          (else
+           (%process-files (option-ref opts '() '())
+                           (option-ref opts 'stdin "guile"))
+           (cond ((option-ref opts 'schedule #f) ;display jobs schedule
+                  => (λ (count)
+                       (display (get-schedule (max 1 (string->number count))))
+                       (exit 0)))
+                 ((option-ref opts 'daemon #f) ;run mcron as a daemon
+                  (case (primitive-fork)
+                    ((0)  (setsid))
+                    (else (exit 0)))))
+           ;; Forever execute the 'run-job-loop', and when it drops out (can
+           ;; only be because a message has come in on the socket) we process
+           ;; the socket request before restarting the loop again.
+           (catch-mcron-error
+            (let ((fdes-list '()))
+              (while #t
+                (run-job-loop fdes-list)
+                ;; we can also drop out of run-job-loop because of a SIGCHLD,
+                ;; so must test FDES-LIST.
+                (unless (null? fdes-list)
+                  (process-update-request fdes-list)))))))))