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//
// login.c
//
// Sign on user
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
// 1. Redistributions of source code must retain the above copyright 
//    notice, this list of conditions and the following disclaimer.  
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.  
// 3. Neither the name of the project nor the names of its contributors
//    may be used to endorse or promote products derived from this software
//    without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
// SUCH DAMAGE.
// 

#include <os.h>
#include <string.h>

#define NAMESIZE 32

int main(int argc, char *argv[])
{
  struct utsname sys;
  char username[NAMESIZE];
  char password[NAMESIZE];
  char *p;
  char ch;
  int rc;
  char enter;
  struct passwd *pwd;
  char *shell;

  // Get system information
  memset(&sys, 0, sizeof(struct utsname));
  uname(&sys);

  // Determine console newline character
  enter = (gettib()->job->term->type == TERM_CONSOLE) ? '\r' : '\n';

  // Print banner
  write(fdout, sys.sysname, strlen(sys.sysname));
  write(fdout, " version ", 9);
  write(fdout, sys.release, strlen(sys.release));
  write(fdout, " (", 2);
  write(fdout, sys.version, strlen(sys.version));
  write(fdout, ")\r\n", 3);

  for (;;)
  {
    // Clear credentials
    memset(username, 0, NAMESIZE);
    memset(password, 0, NAMESIZE);

    // Get user name
    if (argc > 1)
      strncpy(username, argv[1], NAMESIZE);
    else
    {
      while (!*username)
      {
        if (*sys.nodename)
        {
          write(fdout, sys.nodename, strlen(sys.nodename));
          write(fdout, " ", 1);
        }

        write(fdout, "login: ", 7);
        p = username;
        for (;;)
        {
          rc = read(fdin, &ch, 1);
          if (rc < 0) return 0;
          if (ch == 0x03) return 0;
        
          if (ch == '\r' || ch == '\n')
          {
            if (ch == enter)
              break;
            else
              continue;
          }

          if (ch > ' ')
          {
            write(fdout, &ch, 1);
            if (p < username + NAMESIZE - 1) *p++ = ch;
          }
        }
        *p = 0;
        write(fdout, "\r\n", 2);
      }
    }

    // Lookup user in user database
    pwd = getpwnam(username);
    if (pwd && !*pwd->pw_passwd) break;

    // Get password
    write(fdout, "Password: ", 10);
    p = password;
    for (;;)
    {
      rc = read(fdin, &ch, 1);
      if (rc < 0) return 0;
      if (ch == 0x03) return 0;
      
      if (ch == '\r' || ch == '\n')
      {
        if (ch == enter)
          break;
        else
          continue;
      }

      if (p < password + NAMESIZE - 1) *p++ = ch;
    }
    *p = 0;
    write(fdout, "\r\n", 2);

    // Check password
    if (pwd)
    {
      p = crypt(password, pwd->pw_passwd);
      if (p && strcmp(p, pwd->pw_passwd) == 0) 
      {
        memset(password, 0, NAMESIZE);
        break;
      }
    }

    // Login failed
    sleep(2);
    write(fdout, "Login incorrect\r\n", 17);
  }

  // Switch user and group id
  if (initgroups(pwd->pw_name, pwd->pw_gid) < 0 || setgid(pwd->pw_gid) < 0 || setuid(pwd->pw_uid) < 0)
  {
    write(fdout, "Permission denied\r\n", 19);
    return 0;
  }

  // Launch shell
  shell = pwd->pw_shell;
  if (!shell || !*shell) shell = "/bin/sh";
  if (spawn(P_WAIT, NULL, shell, NULL) < 0) 
  {
    write(fdout, "No shell\r\n", 10);
    sleep(2);
  }

  return 0;
}