mdw@git.distorted.org.uk Git - shells/blob - banned.c

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Ban a user from logging in
   6  *
   7  * (c) 1999 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 /*----- Header files ------------------------------------------------------*/
  28
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <sys/types.h>
  34 #include <pwd.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37 #include <syslog.h>
  38
  39 /*----- Main code ---------------------------------------------------------*/
  40
  41 static const char *quis = "banned";
  42
  43 int main(int argc, char *argv[])
  44 {
  45   struct passwd *pw;
  46   int fd;
  47   char buf[BUFSIZ];
  48   int r;
  49
  50   /* --- Resolve the program name --- */
  51
  52   {
  53     char *p, *q;
  54     p = argv[0];
  55     for (q = argv[0]; *q; q++) {
  56       if (*q == '/')
  57         p = q + 1;
  58     }
  59     quis = p;
  60   }
  61
  62   /* --- Read the user's name --- */
  63
  64   pw = getpwuid(getuid());
  65   if (!pw) {
  66     fprintf(stderr, "%s: you don't exist.  Go away.\n", quis);
  67     exit(EXIT_FAILURE);
  68   }
  69
  70   /* --- Open the log file --- */
  71
  72   openlog(quis, 0, LOG_AUTH);
  73   syslog(LOG_CRIT, "banned user `%s' attempted to log in", pw->pw_name);
  74
  75   /* --- Change directory to the user's home --- */
  76
  77   if (chdir(pw->pw_dir) < 0) {
  78     fprintf(stderr, "%s: couldn't change directory: %s\n",
  79             quis, strerror(errno));
  80     exit(EXIT_FAILURE);
  81   }
  82
  83   /* --- Open the reason file --- */
  84
  85   if ((fd = open(".banned", O_RDONLY)) < 0) {
  86     fprintf(stderr, "%s: couldn't open `.banned' file: %s\n",
  87             quis, strerror(errno));
  88     exit(EXIT_FAILURE);
  89   }
  90
  91   /* --- Dump the reason information out --- */
  92
  93   for (;;) {
  94     r = read(fd, buf, sizeof(buf));
  95     if (r == 0)
  96       break;
  97     else if (r < 0) {
  98       fprintf(stderr, "%s: couldn't read: %s\n", quis, strerror(errno));
  99       exit(EXIT_FAILURE);
 100     }
 101     write(STDOUT_FILENO, buf, r);
 102   }
 103
 104   /* --- Done --- */
 105
 106   close(fd);
 107   return (EXIT_FAILURE);
 108 }
 109
 110 /*----- That's all, folks -------------------------------------------------*/