project: banish need for C compiler

This patch gets rid of the thin veneer that we currently have around the three
executables.  This was done for historical reasons (circa 2003 Guile couldnʼt
deal with process signals and forks).  In fact these problems were fixed many
moons ago, and there is now no need for it.  The project becomes 100% Guile!

Many files are affected; interested coders should use the GIT repository to
understand the details of all the changes.

5 files changed, 157 insertions, 91 deletions

diff --git a/src/mcron/base.scm b/src/mcron/base.scm
index edcf1bc..f7b727d 100644
--- a/src/mcron/base.scm
+++ b/src/mcron/base.scm
@@ -139,7 +139,7 @@ entries that are to run at this time.  When SCHEDULE is empty next time is
 (define* (display-schedule count #:optional (port (current-output-port))
                            #:key (schedule %global-schedule))
   "Display on PORT a textual list of the next COUNT jobs to run.  This
-simulates the run of the job loop to display the resquested information.
+simulates the run of the job loop to display the requested information.
 Since calling this procedure has the effect of mutating the job timings, the
 program must exit after.  Otherwise the internal data state will be left
 unusable."
diff --git a/src/mcron/job-specifier.scm b/src/mcron/job-specifier.scm
index 120bf99..7eb2304 100644
--- a/src/mcron/job-specifier.scm
+++ b/src/mcron/job-specifier.scm
@@ -202,14 +202,14 @@ go into the list.  For example, (range 1 6 2) returns '(1 3 5)."
 ;; The job function, available to configuration files for adding a job rule to
 ;; the system.
 ;;
-;; Here we must 'normalize' the next-time-function so that it is always a lambda
-;; function which takes one argument (the last time the job ran) and returns a
-;; single value (the next time the job should run). If the input value is a
-;; string this is parsed as a Vixie-style time specification, and if it is a
-;; list then we arrange to eval it (but note that such lists are expected to
-;; ignore the function parameter - the last run time is always read from the
-;; %CURRENT-ACTION-TIME parameter object). A similar normalization is applied to
-;; the action.
+;; Here we must 'normalize' the next-time-function so that it is always a
+;; lambda function which takes one argument (the last time the job ran) and
+;; returns a single value (the next time the job should run). If the input
+;; value is a string this is parsed as a Vixie-style time specification, and
+;; if it is a list then we arrange to eval it (but note that such lists are
+;; expected to ignore the function parameter - the last run time is always
+;; read from the %CURRENT-ACTION-TIME parameter object). A similar
+;; normalization is applied to the action.
 ;;
 ;; Here we also compute the first time that the job is supposed to run, by
 ;; finding the next legitimate time from the current configuration time (set
@@ -229,7 +229,8 @@ go into the list.  For example, (range 1 6 2) returns '(1 3 5)."
          (cond ((procedure? time-proc) time-proc)
                ((string? time-proc)    (parse-vixie-time time-proc))
                ((list? time-proc)      (lambda (current-time)
-                                         (primitive-eval time-proc)))
+                                         (eval time-proc
+                               (resolve-module '(mcron job-specifier)))))
                (else
                 (throw 'mcron-error 3
                        "job: invalid first argument (next-time-function; "
diff --git a/src/mcron/scripts/cron.scm b/src/mcron/scripts/cron.scm
index 1a97fdf..25c8a1a 100644
--- a/src/mcron/scripts/cron.scm
+++ b/src/mcron/scripts/cron.scm
@@ -17,6 +17,7 @@
 ;;; 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 (ice-9 getopt-long)
   #:use-module (ice-9 ftw)
@@ -28,6 +29,8 @@
   #: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,
@@ -41,12 +44,15 @@ reading all the information in the users' crontabs and in /etc/crontab.
   (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  %options  `((schedule (single-char #\s) (value #t)
+                               (predicate ,string->number))
+                     (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
@@ -60,6 +66,8 @@ received."
     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
@@ -74,6 +82,8 @@ crontab.  This requires that command-type is 'cron."
       (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
@@ -103,9 +113,6 @@ operation.  The permissions on the /var/cron/tabs directory enforce this."
     (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
@@ -138,42 +145,53 @@ option.\n")
   (let ((opts (getopt-long 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-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)))))))))
+    (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)
+                      => (λ (count)
+                           (display-schedule (max 1 (string->number count)))
+                           (exit 0)))))))
+
+  ;; Daemonize ourself.
+  (unless  (eq? 0 (primitive-fork))  (exit 0))
+  (setsid)
+
+  ;; Set up process signal handlers, as signals are the only way to terminate
+  ;; the daemon and we MUST be graceful in defeat.
+  (for-each   (λ (x)  (sigaction  x
+                          (λ (sig)  (catch #t
+                                           (λ ()
+                                             (delete-file config-pid-file)
+                                             (delete-file config-socket-file))
+                                           noop)
+                             (exit EXIT_FAILURE))))
+                '(SIGTERM SIGINT SIGQUIT SIGHUP))
+
+  ;; We can now write the PID file.
+  (with-output-to-file  config-pid-file
+                        (λ () (display (getpid)) (newline)))
+
+  ;; 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
index 902d3fc..480eadc 100644
--- a/src/mcron/scripts/crontab.scm
+++ b/src/mcron/scripts/crontab.scm
@@ -25,13 +25,13 @@
   #:use-module (mcron vixie-specification)
   #:export (main))
 
-(define* (show-help)
+(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")
+       -r      (delete user's crontab)")
   (newline)
   (show-package-information))
 
diff --git a/src/mcron/scripts/mcron.scm b/src/mcron/scripts/mcron.scm
index 8ae61cf..0da1cdf 100644
--- a/src/mcron/scripts/mcron.scm
+++ b/src/mcron/scripts/mcron.scm
@@ -19,14 +19,40 @@
 
 (define-module (mcron scripts mcron)
   #:use-module (ice-9 ftw)
+  #:use-module (ice-9 getopt-long)
+  #:use-module (ice-9 local-eval)
   #:use-module (ice-9 rdelim)
   #:use-module (mcron base)
   #:use-module (mcron config)
-  #:use-module (mcron job-specifier)    ;for user/system files
+  #:use-module (mcron job-specifier)    ; For user/system files.
   #:use-module (mcron utils)
   #:use-module (mcron vixie-specification)
   #:export (main))
 
+
+
+(define (show-help)
+  (display "Usage: mcron [OPTION...] [FILE...]
+Run an mcron process according to the specifications in the FILE... (`-' for
+standard input), or use all the files in ~/.config/cron (or the deprecated
+~/.cron) with .guile or .vixie extensions.
+
+  -d, --daemon               Run as a daemon process
+  -i, --stdin=(guile|vixie)  Format of data passed as standard input or file
+                             arguments (default guile)
+  -s, --schedule[=N]         Display the next N (or 8) jobs that will be run
+  -?, --help                 Give this help list
+  -V, --version              Print program version
+
+Mandatory or optional arguments to long options are also mandatory or optional
+for any corresponding short options.
+
+Report bugs to bug-mcron@gnu.org.
+
+"))
+
+
+
 (define process-user-file
   (let ((guile-regexp (make-regexp "\\.gui(le)?$"))
         (vixie-regexp (make-regexp "\\.vix(ie)?$")))
@@ -35,15 +61,17 @@
 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))
+                  (if (string=? input "vixie")
+                      (read-vixie-port (current-input-port))
                       (eval-string (read-string)
                                    (resolve-module '(mcron job-specifier)))))
             ((or guile-syntax? (regexp-exec guile-regexp file-name))
                   (eval-string (read-delimited "" (open-input-file file-name))
                                (resolve-module '(mcron job-specifier))))
             ((regexp-exec vixie-regexp file-name)
-             (read-vixie-file 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
@@ -67,6 +95,8 @@ $XDG_CONFIG_HOME is not defined uses ~/.config/cron instead)."
       (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)
@@ -77,30 +107,47 @@ $XDG_CONFIG_HOME is not defined uses ~/.config/cron instead)."
 ;;; Entry point.
 ;;;
 
-(define* (main #:optional (opts '()))
-  (when config-debug
-    (debug-enable 'backtrace))
-
-  (%process-files (or (assq-ref opts 'files) '())
-                  (if (assq-ref opts 'vixie) "vixie" "guile"))
-
-  (cond ((assq-ref opts 'schedule) ;display jobs schedule
-         => (λ (count)
-              (display-schedule (max 1 count))
-              (exit 0)))
-        ((assq-ref opts 'daemon) ;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))))))
+(define (main)
+
+  (let ((options
+            (getopt-long
+                (command-line)
+                `((daemon   (single-char #\d) (value #f))
+                  (stdin    (single-char #\i) (value #t)
+                            (predicate ,(λ (in) (or (string=? in "guile")
+                                                    (string=? in "vixie")))))
+                  (schedule (single-char #\s) (value optional)
+                            (predicate ,string->number))
+                  (help     (single-char #\?))
+                  (version  (single-char #\V))))))
+
+    (cond ((option-ref options 'help #f)      (show-help)             (exit 0))
+          ((option-ref options 'version #f)   (show-version "mcron")  (exit 0)))
+  
+    (when config-debug
+      (debug-enable 'backtrace))
+
+    (%process-files (option-ref options '() '())
+                    (option-ref options 'stdin "guile"))
+
+    (cond ((option-ref options 'schedule #f)
+               => (λ (count)
+                     (let ((c (if (string? count) (string->number count) 8)))
+                       (display-schedule  (if (exact-integer? c) (max 1 c) 8)))
+                     (exit 0)))
+          ((option-ref options 'daemon #f)
+               (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)))))))