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

   1 /* -*-c-*-
   2  *
   3  * $Id: banned.c,v 1.1 1999/04/20 00:19:04 mdw Exp $
   4  *
   5  * Ban a user from logging in
   6  *
   7  * (c) 1999 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of banned.
  13  *
  14  * banned is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * banned is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with banned; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: banned.c,v $
  32  * Revision 1.1  1999/04/20 00:19:04  mdw
  33  * Initial revision
  34  *
  35  */
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include <errno.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <sys/types.h>
  44 #include <pwd.h>
  45 #include <unistd.h>
  46 #include <fcntl.h>
  47 #include <syslog.h>
  48
  49 /*----- Main code ---------------------------------------------------------*/
  50
  51 static const char *quis = "banned";
  52
  53 int main(int argc, char *argv[])
  54 {
  55   struct passwd *pw;
  56   int fd;
  57   char buf[BUFSIZ];
  58   int r;
  59
  60   /* --- Resolve the program name --- */
  61
  62   {
  63     char *p, *q;
  64     p = argv[0];
  65     for (q = argv[0]; *q; q++) {
  66       if (*q == '/')
  67         p = q + 1;
  68     }
  69     quis = p;
  70   }
  71
  72   /* --- Read the user's name --- */
  73
  74   pw = getpwuid(getuid());
  75   if (!pw) {
  76     fprintf(stderr, "%s: you don't exist.  Go away.\n", quis);
  77     exit(EXIT_FAILURE);
  78   }
  79
  80   /* --- Open the log file --- */
  81
  82   openlog(quis, 0, LOG_AUTH);
  83   syslog(LOG_CRIT, "banned user `%s' attempted to log in", pw->pw_name);
  84
  85   /* --- Change directory to the user's home --- */
  86
  87   if (chdir(pw->pw_dir) < 0) {
  88     fprintf(stderr, "%s: couldn't change directory: %s\n",
  89             quis, strerror(errno));
  90     exit(EXIT_FAILURE);
  91   }
  92
  93   /* --- Open the reason file --- */
  94
  95   if ((fd = open(".banned", O_RDONLY)) < 0) {
  96     fprintf(stderr, "%s: couldn't open `.banned' file: %s\n",
  97             quis, strerror(errno));
  98     exit(EXIT_FAILURE);
  99   }
 100
 101   /* --- Dump the reason information out --- */
 102
 103   for (;;) {
 104     r = read(fd, buf, sizeof(buf));
 105     if (r == 0)
 106       break;
 107     else if (r < 0) {
 108       fprintf(stderr, "%s: couldn't read: %s\n", quis, strerror(errno));
 109       exit(EXIT_FAILURE);
 110     }
 111     write(STDOUT_FILENO, buf, r);
 112   }
 113
 114   /* --- Done --- */
 115
 116   close(fd);
 117   return (EXIT_FAILURE);
 118 }
 119
 120 /*----- That's all, folks -------------------------------------------------*/