/*
  Created: 03.19.05 11:34:57 by Attila Nagyidai

  $Id: C\040Console.c,v 1.1.2.1 2003/08/13 00:38:46 neum Exp $

  This file is part of IBSH (Iron Bars Shell) , a restricted Unix shell
  Copyright (C) 2005  Attila Nagyidai

  This program 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
  of the License, or (at your option) any later version.

  This program 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 this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

  Author: Attila Nagyidai
  Email: na@ent.hu

  Co-Author: Shy
  Email: shy@cpan.org

  Co-Author: Witzy
  Email: stazzz@altern.org
  
  URL: http://ibsh.sourceforge.net
  IRC: irc.freenode.net #ibsh
  RSS, Statistics, etc: http://sourceforge.net/projects/ibsh/

*/

/* Header files */
#include "ibsh.h"

/* Main: */
/* Handle arguments, read config files, start command processing. */
/* IBSH doesnt use any command line arguments, but my text editor */
/* uses this code in all new c files to create. And i didnt have the */
/* heart to remove it. ;p */
/* Technical Description: */
/* Get the passwd entry for the user. The uid is easily aquired, since */
/* it is the real user id. After that, grab the passwd file entry upon */
/* the id, and copy the information to the loggedin struct. */
/* Add some signal handlers too. */
/* The infinite loop: */
/* Get the current directory, the full path. Compute the jailpath from that, */
/* that is the directories below the users homedir, which is the jail root. */
/* The jail ceiling if you like. Print some prompt to the user with the jailpath, */
/* and read stdin for incoming commands. Filter out the bad commands, typos, the */
/* not allowed commands. It the command is ok, execute it. If it is a shell builtin, */
/* use our builtin code, otherwise use execve. After execve, check if the user didnt */
/* use the last command to create some illegal content. If yes, erase that. Give the */
/* notice only afterwards. */
int main(int argc, char **argv)
{
  char temp[STRING_SIZE], *buf;
  struct stat info;
  uid_t ruid, euid;
  gid_t rgid, egid;


  /* setuid protection */
  ruid = getuid();
  euid = geteuid();
  rgid = getgid();
  egid = getegid();
  if ( (ruid!=euid) || (ruid==0) || (euid==0) || (rgid!=egid) || (rgid==0) || (egid==0) ) {
      OPENLOG;
      syslog(LOG_ERR, "setuid/setgid violation!");
      CLOSELOG;
      printf("ibsh: setuid/setgid violation!! exiting...\n");
#ifdef DEBUG
      printf("ruid: %d;euid: %d;rgid: %d;egid: %d\n", ruid,euid,rgid,egid);
#endif
      exit(0);
  }

  /* To Do: The code of your application goes here */
  /* First part: */
  /* Get essential information about the user who got this shell: */
  /* first the username, then the user id. Upon this, retrieve the */
  /* user's record in the passwd file. */
  bzero(&loggedin, sizeof(loggedin));
  loggedin.uid = getuid();
  loggedin.record = getpwuid(loggedin.uid);
  if ( loggedin.record == NULL ) {
      loggedin.record = getpwnam(loggedin.uname);
      if ( loggedin.record == NULL ) {
          openlog(loggedin.uname, LOG_PID, LOG_AUTH);
          syslog(LOG_ERR, "Can not obtain user information");
          closelog();
          exit(0);
      }
  }
  strncpy(loggedin.uname, loggedin.record->pw_name, PAM_SIZE);
  strncpy(loggedin.udir, loggedin.record->pw_dir, STRING_SIZE);

  /* Second part: */
  /* Handle some signal catching. Read the configuration files. */
  signal( SIGINT, SIG_IGN );
  signal( SIGQUIT, SIG_IGN );
  signal( SIGTERM, SIG_IGN );
  signal( SIGTSTP, SIG_IGN );
  LoadConfig();

  /* Command mode */
  if(argc == 3) {
      if ( argv[1][1] == 'c' ) {
          if ( CommandOK(argv[2], loggedin.udir, "/", filtered_command) == 1) {
                exitcode = hhsystem(filtered_command);
                OPENLOG;
                syslog(LOG_INFO, "command %s ordered, command %s has been executed.",
                argv[2], filtered_command);
                CLOSELOG;
                exit(exitcode);
          }
          exit(0);
      }
      else {
        exit(0);
      }
  }

  OPENLOG;
  syslog(LOG_INFO, "user %s has logged in.", loggedin.uname);
  CLOSELOG;


  DelBadFiles(loggedin.udir);
  chdir (loggedin.udir);


  /* Third part: */
  /* Start reading and processing the user issued commands. */
  /* Split the command by the spaces, filter out anything, */
  /* that would allow the user to access files outside the */
  /* jail. Filter out multiples and pipes as well. No program */
  /* will be allowed to run, unless it is mentioned in the */
  /* config files. Files that are created with an extension */
  /* that is listed in the other config file, must be deleted! */
  for ( ; ; ) {
    /* Where is he ? */
    getcwd(real_path, STRING_SIZE);
    GetPositionInJail(real_path, loggedin.udir, jail_path);
    if ( (strlen(jail_path)) == 0 ) {
        strncpy(jail_path, "/", 2);
    }
    /* We don't want the user to know where he actually is. */
    /* This is the prompt! */
    printf("[%s]%% ", jail_path);
    /* scanf("%s", user_command); */
    myscanf(user_command, real_path);
    /* Command interpretation and execution. */
    if ( (CommandOK(user_command, loggedin.udir, jail_path, filtered_command)) == 0 ) {
        printf("Sorry, can't let you do that!\n");
        log_attempt(loggedin.uname);  /* v0.2a */
        continue;
    }
    /* If the user issued command starts with a shell builtin. */
    bzero(temp, strlen(temp));
    if ( (buf = strstr(filtered_command, "cd")) != NULL ) {
      if ( (strcmp(buf, filtered_command)) == 0 ) {
          LTrim3(filtered_command, temp);
          if ( (strcmp(temp, real_path)) != 0 ) {
            if ( (strcmp(temp, "..")) == 0 ) {
                PathMinusOne(jail_path, temp, 1,sizeof(temp));
            }
            if ( (strcmp(temp, "/")) == 0 ) {
                strncpy(temp, loggedin.udir, LINE_SIZE);
            }
            exitcode = chdir(temp);
            if ( exitcode == -1 ) {
                printf("ibsh: cd: %s: No such file or directory\n", temp);
            }
          }
          continue;
      }
    }
    else if ( (buf = strstr(filtered_command, "pwd")) != NULL ) {
     if ( (strcmp(buf, filtered_command)) == 0 ) {
          printf("%s\n", jail_path);
          continue;
      }
    }
    else if ( (buf = strstr(filtered_command, "logout")) != NULL ) {
      if ( (strcmp(buf, filtered_command)) == 0 ) {
          OPENLOG;
          syslog(LOG_INFO, "user %s has logged out.", loggedin.uname);
          CLOSELOG;
          break;
      }
    }
    else if ( (buf = strstr(filtered_command, "exit")) != NULL ) {
      if ( (strcmp(buf, filtered_command)) == 0 ) {
          OPENLOG;
          syslog(LOG_INFO, "user %s has logged out.", loggedin.uname);
          CLOSELOG;
          break;
      }
    }
    else {
        exitcode = hhsystem(filtered_command);
        if ( exitcode < 0 ) {
            printf("%s\n", strerror(errno));
        }
    }
    getcwd(real_path, STRING_SIZE);
    DelBadFiles(loggedin.udir);
    chdir (real_path);
  }
  return 0;
}