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Diffstat (limited to 'mcron.c.template')
| -rw-r--r-- | mcron.c.template | 120 |
1 files changed, 0 insertions, 120 deletions
diff --git a/mcron.c.template b/mcron.c.template deleted file mode 100644 index e9a755d..0000000 --- a/mcron.c.template +++ /dev/null @@ -1,120 +0,0 @@ -/* -*-c-*- */ -/* - * 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/>. - */ - - -/* - This C code represents the thinnest possible wrapper around the Guile code - which constitutes all the functionality of the mcron program. There are two - plus one reasons why we need to do this, and one very unfortunate - consequence. - - Firstly, SUID does not work on an executable script. In the end, it is - the execution of the translator, in our case guile, which determines the - effective user, and it is not wise to make the system guile installation - SUID root! - - Secondly, executable scripts show up in ugly ways in listings of the - system process table. Guile in particular, with its multi-line - #! ...\ \n -s ...!# - idiosyncracies shows up in process listings in a way that is difficult - to determine what program is actually running. - - A third reason for the C wrapper which might be mentioned is that a - security-conscious system administrator can choose to only install a - binary, thus removing the possibility of a user studying a guile script - and working out ways of hacking it to his own ends, or worse still - finding a way to modify it to his own ends. - - Unfortunately, running the guile script from inside a C program means - that the sigaction function does not work. Instead, it is necessary to - perform the signal processing in C. - - The guile code itself is substituted for the GU1LE_PROGRAM_GOES_HERE (sic) - token by the makefile, which processes the scheme to make it look like one - big string. -*/ - - - -#include <string.h> -#include <signal.h> -#include <libguile.h> - - - -/* This is a function designed to be installed as a signal handler, for signals - which are supposed to initiate shutdown of this program. It calls the scheme - procedure (see mcron.scm for details) to do all the work, and then exits. */ - -void -react_to_terminal_signal (int sig) -{ - scm_c_eval_string ("(delete-run-file)"); - exit (1); -} - - - -/* This is a function designed to be callable from scheme, and sets up all the - signal handlers required by the cron personality. */ - -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; -} - - - -/* The effective main function (i.e. the one that actually does some work). We - register the function above with the guile system, and then execute the mcron - guile program. */ - -void -inner_main () -{ - scm_c_define_gsubr ("c-set-cron-signals", 0, 0, 0, set_cron_signals); - - scm_c_eval_string ( - GUILE_PROGRAM_GOES_HERE - ); -} - - - -/* The real main function. Does nothing but start up the guile subsystem. */ - -int -main (int argc, char **argv) -{ - setenv ("GUILE_LOAD_PATH", GUILE_LOAD_PATH, 1); - - scm_boot_guile (argc, argv, inner_main, 0); - - return 0; -} |