/*
Copyright (C) 1993, 1996, 1997, 2003, 2008, 2009, 2010 Free Software Foundation, Inc.

This file is part of the GNU Accounting Utilities

The GNU Accounting Utilities are free software; you can redistribute
them and/or modify them under the terms of the GNU General Public
License as published by the Free Software Foundation; either version
3, or (at your option) any later version.

The GNU Accounting Utilities are distributed in the hope that they 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 the GNU Accounting Utilities; see the file COPYING.  If
not, write to the Free Software Foundation, 675 Mass Ave, Cambridge,
MA 02139, USA.
*/

#include "config.h"
#include <stdio.h>

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <ctype.h>

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include <sys/types.h>

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#ifdef AMIX
#include </usr/ucbinclude/sys/signal.h>
#else
#include <signal.h>
#endif

#include "common.h"
#include "files.h"
#include "utmp_rd.h"
#ifdef HAVE_GETOPT_LONG_ONLY
#include <getopt.h>
#else
#include "getopt.h"
#endif
#include "hashtab.h"
#include "version.h"


/* globals */

char *program_name;		/* name of the program, for usage */

int debugging_enabled = 0;	/* Nonzero means print internal
				   information relating to entries
				   read, data structures, etc. */

long time_warp_leniency = 60;	/* Number of seconds that an entry can
				   be "before" the previous one -- to
				   deal with simultaneous init(8)
				   writes, or to overlook problems
				   with sun's wtmp files. */

long time_warp_suspicious = 31536000; /* Anything smaller than this
					 jump will be considered
					 normal.  A year is pretty
					 safe to assume... */

int print_file_problems = 0;	/* when there's a problem with the
				   file's format, scream! */

int print_year = 0;		/* Print the year when displaying
				   dates. */

int print_seconds = 0;		/* Print the seconds when displaying
				   dates. */

time_t last_time = 0;		/* time of last event (error checking)
				   needs to be a global so that the
				   signal handler can get at its value
				   when the program is interrupted */


char *last_event = NULL;	/* Set to NULL initially (means that a
				   user is still logged on) but
				   changed to "crash" or "down" as
				   appropriate. */

time_t last_event_time;		/* last time the machine rebooted/shutdown */

long num_lines_to_print = -1;	/* the -n option -- starts out at -1,
				   which is a signal to the program
				   not to limit the number of lines
				   printed. */

int truncate_ftp_entries = 1;	/* Nonzero means shorten "ftpxxx"
				   entries to "ftp" -- most progs do
				   this by default, but we should have
				   a flag for it */

#ifdef HAVE_STRUCT_UTMP_UT_TYPE
int print_which_recs = 0;	/* If 0, only print the usual.  If 1,
				   print run level information,
				   shutdowns, and time changes.  If 2
				   or greater, print the whole, dirty
				   business. */
#endif

#ifdef HAVE_STRUCT_UTMP_UT_ADDR
int print_addresses = 0;	/* should we print the ut_addr field? */
#endif

/* Some systems (like Linux with the newer glibc) have very long field
   lengths for usernames, ttys, and hostnames.  While it's useful to
   print out the entire values from time to time, the casual browser
   doesn't care (and it screws up the 80-column formatting).  Keep
   track of desired field widths with these variables. */

#define my_min(x,y) ((x) < (y) ? (x) : (y))
int print_name_len = my_min (NAME_LEN, 8);
int print_tty_len = my_min (TTY_LEN, 12);
int print_host_len = my_min (HOST_LEN, 16);
#undef my_min


/* A table of names/ttys that the user wants to know about.  */

struct hashtab *names = NULL;

/* A table of logins/logouts. */

struct hashtab *login_table = NULL;

struct login_data
{
  time_t time;
  short fake_entry;
};

void log_everyone_in (time_t);
void update_system_time (time_t);
void log_out (struct utmp *entry, short fake_flag);
void log_in (struct utmp *);
void print_record (struct utmp *, time_t logout_time,
                   char *, char *, char *);
void display_date (time_t now);

struct sigaction sigact;
#if defined (SVR4) && !defined (_POSIX_SOURCE)
RETSIGTYPE handler (int, int, struct sigcontext *);
#else
RETSIGTYPE handler (int);
#endif

/* code */

int main(int argc, char *argv[])
{
  int c = 1;
  int other_wtmp_file_specified = 0; /* nonzero if the user used the
					`-f' or `--file' flags */

  program_name = argv[0];

  /* Tell the utmp reader that we want to do things backwards! */

  utmp_init (1);

  /* Read options */

  /* Aaargh!  We've got to parse the arguments manually before we give
     them to getopt, since it can't handle `last -10' and things like
     it... */

  for (; c < argc; c++)
    {
      if (argv[c][0] == '-' && isdigit (argv[c][1]))
        {
          /* This looks like an old-style option -- read the number! */
          int d;

          num_lines_to_print = strtol (argv[c] + 1, (char **)NULL, 10);
          if (num_lines_to_print < 1)
            fatal ("number of lines to print must be positive and non-zero");

          /* renumber the argv options */
          for (d = c; d; d--)
            argv[d] = argv[d - 1];

          argc--;
          argv++;
          c--;
        }
    }

  while (1)
    {
      int option_index = 0;

      static struct option long_options[] =
      {
        { "complain", no_argument, NULL, 1
        },
        { "lines", required_argument, NULL, 3 },
        { "debug", no_argument, NULL, 4 },
        { "tw-leniency", required_argument, NULL, 5 },
        { "version", no_argument, NULL, 6 },
        { "help", no_argument, NULL, 7 },
        { "file", required_argument, NULL, 8 },
        { "no-truncate-ftp-entries", no_argument, NULL, 9 },
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
        { "all-records", no_argument, NULL, 10 },
#endif
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
        { "ip-address", no_argument, NULL, 11 },
#endif
        { "print-year", no_argument, NULL, 12 },
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
        { "more-records", no_argument, NULL, 13 },
#endif
        { "tw-suspicious", required_argument, NULL, 14 },
        { "print-seconds", no_argument, NULL, 15 },
        { "wide", no_argument, NULL, 16 },
        { 0, 0, 0, 0 }
      };

      c = getopt_long (argc, argv,
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
                       "a"
#endif
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
                       "i"
#endif
                       "f:n:s"
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
                       "x"
#endif
                       "wyV",
                       long_options, &option_index);

      if (c == EOF)
        break;

      switch (c)
        {
        case 1:
          print_file_problems = 1;
          break;
        case 'n':
        case 3:
          num_lines_to_print = strtol(optarg, (char **)NULL, 10);
          if (num_lines_to_print < 1)
            fatal ("number of lines to print must be positive and non-zero");
          break;
        case 4:
          debugging_enabled = 1;
          print_file_problems = 1;
          break;
        case 5:
          time_warp_leniency = strtol(optarg, (char **)NULL, 10);
          if (time_warp_leniency < 0)
            fatal ("time warp leniency value has to be non-negative");
          break;
        case 'V':
        case 6:
          printf ("%s: GNU Accounting Utilities (release %s)\n",
                  program_name, VERSION_STRING);
          exit(EXIT_SUCCESS);
        case 'f':
        case 8:
          add_utmp_file (optarg);
          other_wtmp_file_specified = 1;
          break;
        case 9:
          truncate_ftp_entries = 0;
          break;
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
        case 'a':
        case 10:
          print_which_recs = 2;
          break;
#endif
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
        case 'i':
        case 11:
          print_addresses = 1;
          break;
#endif
        case 'y':
        case 12:
          print_year = 1;
          break;
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
        case 'x':
        case 13:
          print_which_recs = 1;
          break;
#endif
        case 14:
          time_warp_suspicious = strtol(optarg, (char **)NULL, 10);
          if (time_warp_suspicious < 0)
            fatal ("time warp suspicious value has to be non-negative");
          if (time_warp_suspicious <= time_warp_leniency)
            fatal ("time warp suspicious value has to greater than the time warp leniency value");
          break;
        case 's':
        case 15:
          print_seconds = 1;
          break;
        case 'w':
        case 16:
          /* Print the entire field widths, rather than our
                   conservative, 80-column defaults */
          print_name_len = NAME_LEN;
          print_tty_len = TTY_LEN;
          print_host_len = HOST_LEN;
          break;
        case 'h':
        case 7:
          /* This should fall through to default! */
        default:
          give_usage();
          exit(EXIT_FAILURE);
        }
    }

  /* Init the hash table for usernames.  Don't init it if we don't
     have any extra arguments so we can quickly check if we have
     anything in the list. */

  if (optind < argc)
    {
      names = hashtab_init (0);

      while (optind < argc)
        {
          char *string;

          /* add the username/tty as-is */

          hashtab_create (names, argv[optind], 0);

          /* add the name as "tty<name>" for u*x compatibilty */

          string = (char *) xmalloc ((strlen (argv[optind]) + 4)
                                     * sizeof (char));
          sprintf (string, "tty%s", argv[optind]);
          hashtab_create (names, string, 0);
          free (string);

          optind++;

#ifdef HAVE_STRUCT_UTMP_UT_TYPE
          if (!print_which_recs)
            print_which_recs = 1;
#endif
        }

      if (debugging_enabled)
        hashtab_dump_keys (names, stddebug);
    }

  if (! other_wtmp_file_specified)
    add_utmp_file (WTMP_FILE_LOC);

  /* Create hash table for logins. */

  login_table = hashtab_init (0);

  /* Go! */

  parse_entries ();

  (void)fputs ("\nwtmp begins ", stdout);
  display_date (last_time);
  (void)fputc ('\n', stdout);

  exit (EXIT_SUCCESS);			/* a GUARANTEED return value to the env */
}

/* guess what this does... */

void give_usage(void)
{
  (void)printf("\
                Usage: %s [-"
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
               "a"
#endif
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
               "i"
#endif
               "hs"
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
               "x"
#endif
               "yV] [-<lines>] [-n <lines>] [-f <file>] [people] [ttys] ...\n\
                [--lines <num>] [--file <file>] [--complain] [--debug]\n\
                [--version] [--tw-leniency <value>] [--tw-suspicious <value>]\n\
                [--no-truncate-ftp-entries] [--print-year] [--print-seconds]\n\
                "
#ifdef HAVE_STRUCT_UTMP_UT_TYPE
               "[--more-records] [--all-records] "
#endif
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
               "[--ip-address] "
#endif
               "[--help]\n", program_name);
  print_wtmp_file_location ();
}

/* Since the routines in ac & last are so similar, just include them
from another file. */

#define BACKWARDS 1
#include "al_share.cpp"

/* since the sys clock has changed, each entry's login time has to be
* adjusted...  */

void update_system_time(time_t the_time)
{
  struct hashtab_order ho;
  struct hashtab_elem *he;

  for (he = hashtab_first (login_table, &ho);
       he != NULL;
       he = hashtab_next (&ho))
    {
      struct login_data *l = hashtab_get_value (he);
      l->time += the_time;
    }
}

/* Log all entries in at THE_TIME. */

void log_everyone_in(time_t the_time)
{
  struct hashtab_order ho;
  struct hashtab_elem *he;

  for (he = hashtab_first (login_table, &ho);
       he != NULL;
       he = hashtab_next (&ho))
    {
      struct login_data *l = hashtab_get_value (he);

      /* If there was a real log out record present in the file
      without a corresponding login, we should print it. */

      if (debugging_enabled && (! l->fake_entry))
        {
          struct utmp this;
          char *ttyname = hashtab_get_key (he);

          memset (&this, 0, sizeof (this));
          strncpy (this.ut_line, ttyname, TTY_LEN);
          this.ut_time = the_time;

          print_record (&this, l->time, NULL, NULL, "unpaired");
        }

      hashtab_delete (he);
    }
}

/* Put a terminal into the hash table. */

void log_out(struct utmp *entry, short fake_flag)
{
  struct hashtab_elem *he;

  if (entry->ut_line[0] == '\0')
    {
      if (print_file_problems)
        {
          utmp_print_file_and_line (stddebug);
          fprintf (stddebug, ": problem: trying to hash rec with ut_line == NULL\n");
        }
      return;
    }

  /* Match the most recent login on the terminal. */

  he = hashtab_find (login_table, entry->ut_line, (unsigned int)TTY_LEN);

  if (he != NULL)
    {
      struct login_data *l = hashtab_get_value (he);

      if ((! l->fake_entry) && print_file_problems)
        {
          char *ttyname = hashtab_get_key (he);
          utmp_print_file_and_line (stddebug);
          fprintf (stddebug, ": problem: duplicate record for line `%.*s'\n", TTY_LEN, ttyname);
        }

      /* Write over the old values. */

      l->time = entry->ut_time;
      l->fake_entry = fake_flag;

      return;
    }
  else
    {
      /* If we get here, we didn't find the entry in the list, so add
      a new one. */

      struct login_data l;

      l.time = entry->ut_time;
      l.fake_entry = fake_flag;

      he = hashtab_create (login_table, entry->ut_line, TTY_LEN);
      hashtab_set_value (he, &l, sizeof (l));
    }
}

/* Remove an entry from the hash table. */

void log_in(struct utmp *entry)
{
  struct hashtab_elem *he;

  if (entry->ut_line[0] == '\0')
    {
      if (print_file_problems)
        {
          utmp_print_file_and_line (stddebug);
          fprintf (stddebug,
                   ": problem: trying to hash rec with ut_line == NULL\n");
        }
      return;
    }

  he = hashtab_find (login_table, entry->ut_line, (unsigned int)TTY_LEN);

  if (he != NULL)
    {
      struct login_data *l = hashtab_get_value (he);

      if (l->fake_entry && print_file_problems)
        {
          /* If this happens, we assume that the logout time for ENTRY
             is the the same as the next login time on the tty. */

          utmp_print_file_and_line(stddebug);
          (void)fprintf(stddebug, ": problem: missing logout record for `%.*s'\n",
                        TTY_LEN, entry->ut_line);
        }

      print_record(entry, l->time, NULL, NULL, NULL);

      hashtab_delete (he);
    }
  else
    {
      /* We didn't find any corresponding logout, so either the person
      it still logged in or there's a problem with the wtmp file
      (logout without login). */

      print_record (entry, 0, NULL, NULL, NULL);
    }

  /* Make another logout entry at the current time (a fake one) so we
     can detect wtmp file errors (logins without logouts). */

  log_out (entry, TRUE);
}


/* Print the record to the screen.  If LOGOUT_TIME is zero, print out
   the difference in time between LOGIN and the last recorded event
   (crash, down, etc.).  If other strings should be printed for the
   UT_NAME, UT_LINE, or end-of-line fields, they can be passed in as
   the last three arguments. */

void print_record(struct utmp *login, time_t logout_time,
                  char *replacement_name, char *replacement_tty,
                  char *special_message)
{
  char *print_name;
  char *print_tty;
  char sanitized_tty[TTY_LEN];

  /* Do we want to print this entry?  Check our list of user-desired
     items. */

  if (! ((names == NULL)
         || hashtab_find (names, login->ut_name, (unsigned int)NAME_LEN)
         || hashtab_find (names, login->ut_line, (unsigned int)TTY_LEN)))
    return;			/* don't want to print this record */


  /* Choose replacement names, if provided.  Don't do this if we're on
     a BSD system. */

#ifdef HAVE_STRUCT_UTMP_UT_TYPE
  if (replacement_tty)
    print_tty = replacement_tty;
  else
#endif
    if (truncate_ftp_entries && (strncmp (login->ut_line, "ftp", 3) == 0))
      print_tty = "ftp";		/* strip number from "ftpxxx" entry */
    else
      print_tty = login->ut_line;

  print_name = (replacement_name ? replacement_name : login->ut_name);


  /* Sanitize the tty name (get rid of control characters) */

  {
    int i = 0;

    for (; (print_tty[i] != '\0') && (i < TTY_LEN); i++)
      sanitized_tty[i] = (isprint (print_tty[i]) && isascii (print_tty[i])
                          ? print_tty[i]
                          : '?');
    if (i < TTY_LEN)
      sanitized_tty[i] = '\0';
  }

  /* Print the name and tty. */

  (void)printf("%-*.*s %-*.*s ",
               print_name_len, print_name_len, print_name,
               print_tty_len, print_tty_len, sanitized_tty);


#ifdef HAVE_STRUCT_UTMP_UT_ADDR
  if (print_addresses)
    {
      struct in_addr a;
      a.s_addr = login->ut_addr;
      (void)printf("%-15.15s ", (login->ut_addr) ? inet_ntoa (a) : "");
    }
#endif

#ifdef HAVE_STRUCT_UTMP_UT_HOST
#ifdef HAVE_STRUCT_UTMP_UT_ADDR
  /* If we have both HOST and ADDR, only print one, or else we go
         beyond 80 characters in width. */
  if (!print_addresses)
#endif
    (void)printf ("%-*.*s ", print_host_len, print_host_len, login->ut_host);
#endif

  display_date (login->ut_time);

  if (special_message)
    (void)printf ("  %s\n", special_message);
  else
    {
#ifdef HAVE_SNPRINTF
      char temp_str[16];
#else
      char temp_str[15];
#endif
      int days, hours, minutes, seconds;
      int diff, use_last_event = 0;

      if (logout_time == 0)
        {
          logout_time = last_event_time;
          use_last_event = 1;
        }

      diff = (int) logout_time - login->ut_time;
      days = (int) (diff / 86400);
      diff -= 86400 * days;
      hours = (int) (diff / 3600);
      diff -= 3600 * hours;
      minutes = (int) (diff / 60);
      diff -= 60 * minutes;
      seconds = diff;
#ifdef HAVE_SNPRINTF
      if (days)
        {
          if (print_seconds)
            (void)snprintf (temp_str, sizeof(temp_str), "(%d+%02d:%02d:%02d)",
                            days, hours, minutes, seconds);
          else
            (void)snprintf (temp_str, sizeof(temp_str),"(%d+%02d:%02d)", days, hours, minutes);
        }
      else
        {
          if (print_seconds)
            (void)snprintf (temp_str, sizeof(temp_str)," (%02d:%02d:%02d)",
                            hours, minutes, seconds);
          else
            (void)snprintf (temp_str, sizeof(temp_str)," (%02d:%02d)", hours, minutes);
        }
#else
      if (days)
        {
          if (print_seconds)
            (void)sprintf (temp_str, "(%d+%02d:%02d:%02d)",
                           days, hours, minutes, seconds);
          else
            (void)sprintf (temp_str, "(%d+%02d:%02d)", days, hours, minutes);
        }
      else
        {
          if (print_seconds)
            (void)sprintf (temp_str, " (%02d:%02d:%02d)",
                           hours, minutes, seconds);
          else
            (void)sprintf (temp_str, " (%02d:%02d)", hours, minutes);
        }
#endif
      if (use_last_event)
        {
          if (last_event == NULL)

            (void)fputs ("  still logged in\n", stdout);
          else
            (void)printf ("- %-5.5s %s\n", last_event, temp_str);
        }
      else
        {
          struct tm *tmptr;
          time_t temp_time = logout_time;
          tmptr = localtime (&temp_time);
          if (print_seconds)
            printf ("- %02d:%02d:%02d %s\n",
                    tmptr->tm_hour, tmptr->tm_min, tmptr->tm_sec, temp_str);
          else
            printf ("- %02d:%02d %s\n",
                    tmptr->tm_hour, tmptr->tm_min, temp_str);
        }
    }

  if (num_lines_to_print > -1)
    {
      num_lines_to_print--;
      if (num_lines_to_print == 0)    /* max lines printed */
        exit(EXIT_SUCCESS);
    }
}

/* Our signal handler */

RETSIGTYPE
#if defined (SVR4) && !defined (_POSIX_SOURCE)
handler(int sig, int code, struct sigcontext *scp)
#else
handler(int sig)
#endif
{
  (void)fputs ("\ninterrupted at ", stdout);
  display_date (last_time);
  (void)putchar ('\n');
  exit(EXIT_SUCCESS);
}

/* Display the date, paying attention to the PRINT_YEAR flag. */

void display_date(time_t now)
{
  char *ct = ctime (&now);

  printf ("%-10.10s ", ct);

  if (print_year)
    printf ("%-4.4s ", ct + 20);

  if (print_seconds)
    printf ("%-8.8s ", ct + 11);
  else
    printf ("%-5.5s ", ct + 11);
}