/***************************************************************************** * * $Id$ * Purpose ...............: MBSE BBS Shadow Password Suite * Original Source .......: Shadow Password Suite * Original Copyright ....: Julianne Frances Haugh and others. * ***************************************************************************** * Copyright (C) 1997-2001 * * Michiel Broek FIDO: 2:280/2802 * Beekmansbos 10 * 1971 BV IJmuiden * the Netherlands * * This file is part of MBSE BBS. * * This BBS 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 2, or (at your option) any * later version. * * MBSE BBS 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 MBSE BBS; see the file COPYING. If not, write to the Free * Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. *****************************************************************************/ #include "../config.h" #include <stdio.h> #include <errno.h> #include "mblogin.h" #include "basename.h" #include "shell.h" extern char **newenvp; extern size_t newenvc; /* * shell - execute the named program * * shell begins by trying to figure out what argv[0] is going to * be for the named process. The user may pass in that argument, * or it will be the last pathname component of the file with a * '-' prepended. The first attempt is to just execute the named * file. If the errno comes back "ENOEXEC", the file is assumed * at first glance to be a shell script. The first two characters * must be "#!", in which case "/bin/sh" is executed to process * the file. If all that fails, give up in disgust ... */ void shell(const char *file, const char *arg) { char arg0[1024]; int err; if (file == (char *) 0) exit (1); /* * The argv[0]'th entry is usually the path name, but * for various reasons the invoker may want to override * that. So, we determine the 0'th entry only if they * don't want to tell us what it is themselves. */ if (arg == (char *) 0) { snprintf(arg0, sizeof arg0, "-%s", Basename((char *) file)); arg = arg0; } #ifdef DEBUG printf (_("Executing shell %s\n"), file); #endif /* * First we try the direct approach. The system should be * able to figure out what we are up to without too much * grief. */ execle (file, arg, (char *) 0, newenvp); err = errno; /* Linux handles #! in the kernel, and bash doesn't make sense of "#!" so it wouldn't work anyway... --marekm */ #ifndef __linux__ /* * It is perfectly OK to have a shell script for a login * shell, and this code attempts to support that. It * relies on the standard shell being able to make sense * of the "#!" magic number. */ if (err == ENOEXEC) { FILE *fp; if ((fp = fopen (file, "r"))) { if (getc (fp) == '#' && getc (fp) == '!') { fclose (fp); execle ("/bin/sh", "sh", file, (char *) 0, newenvp); err = errno; } else { fclose (fp); } } } #endif /* * Obviously something is really wrong - I can't figure out * how to execute this stupid shell, so I might as well give * up in disgust ... */ snprintf(arg0, sizeof arg0, "Cannot execute %s", file); errno = err; perror(arg0); exit(1); }