1 files changed, 85 insertions, 0 deletions
diff --git a/src/wrapper.c b/src/wrapper.c
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+++ b/src/wrapper.c
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+/* wrapper.c -- C code booting Guile
+   Copyright (C) 2003, 2014 Dale Mellor
+   Copyright (C) 2015, 2016 Mathieu Lirzin
+
+   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/>.  */
+
+/* This C code represents a thin wrapper around the Guile code of Mcron.  It
+   is needed because the crontab personality requires SUID which is not
+   permitted for executable scripts.  */
+
+#include <libguile.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Forward declarations.  */
+static void inner_main (void *closure, int argc, char **argv);
+static void react_to_terminal_signal (int sig);
+static SCM set_cron_signals (void);
+
+int
+main (int argc, char **argv)
+{
+  scm_boot_guile (argc, argv, inner_main, 0);
+
+  return EXIT_SUCCESS;
+}
+
+/* Launch the Mcron Guile main program.  */
+static void
+inner_main (void *closure, int argc, char **argv)
+{
+  /* Set Guile load paths to ensure that Mcron modules will be found.  */
+  if (getenv ("MCRON_UNINSTALLED") == NULL)
+    {
+      scm_c_eval_string ("(set! %load-path (cons \""
+                         PACKAGE_LOAD_PATH "\" %load-path))");
+      scm_c_eval_string ("(set! %load-compiled-path (cons \""
+                         PACKAGE_LOAD_PATH "\" %load-compiled-path))");
+    }
+  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)");
+}
+
+/* Set up all the signal handlers as required by the cron personality.  This
+   is necessary to perform the signal processing in C because the sigaction
+   function won't work when called from Guile.  */
+static SCM
+set_cron_signals ()
+{
+  static struct sigaction sa;
+
+  memset (&sa, 0, sizeof (sa));
+  sa.sa_handler = react_to_terminal_signal;
+  sigaction (SIGTERM, &sa, 0);
+  sigaction (SIGINT,  &sa, 0);
+  sigaction (SIGQUIT, &sa, 0);
+  sigaction (SIGHUP,  &sa, 0);
+
+  return SCM_BOOL_T;
+}
+
+/* Handle signal SIG and exit.  All signals that mcron handles will produce
+   the same behavior so we don't need to use SIG in the implementation.  */
+static void
+react_to_terminal_signal (int sig)
+{
+  scm_c_eval_string ("(delete-run-file)");
+  exit (EXIT_FAILURE);
+}