Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!apple!vsi1!wyse!mips!prls!philabs!micomvax!ncc!alberta!ubc-cs!ubc-bdcvax!holm
From: holm@ubc-bdcvax.UUCP (Terrence W. Holm)
Newsgroups: comp.os.minix
Subject: last(1)
Message-ID: <414@ubc-bdcvax.UUCP>
Date: 2 Feb 89 00:13:18 GMT
Lines: 731


EFTH MINIX report #65  - February 1989 -  last(1)


Last(1) was originally posted as EFTH report #21 (June 1988).
Here it is again, for those who missed it.

You should change the first log call in tools/init.c to
wtmp("~", "reboot") because last(1) knows about both reboot
and shutdown records and we should get this right in init.

		Terrence W. Holm
		  holm@bdc.ubc.ca


----------------------------------------------------------
echo x - last.c
gres '^X' '' > last.c << '/'
X/* last(1)		Display the user log-in history.
X *
X * Author: Terrence W. Holm	May 1988
X */
X
X
X#include <utmp.h>
X#include <stdio.h>
X#include <signal.h>
X
X#ifndef  WTMP
X#define  WTMP   "/usr/adm/wtmp"
X#endif
X
X#define  FALSE	0
X#define  TRUE	1
X
X#define  BUFFER_SIZE     4096	/*  Room for wtmp records	*/
X#define  MAX_WTMP_COUNT  ( BUFFER_SIZE / sizeof(struct utmp) )
X
X#define  min( a, b )     ( (a < b) ? a : b )
X#define  max( a, b )	 ( (a > b) ? a : b )
X
X
Xextern long  time();
Xint   Sigint();
Xint   Sigquit();
X
X
Xtypedef  struct  logout		/*  A logout time record	*/
X  {
X  char  line[8];		/*  The terminal name		*/
X  long  time;			/*  The logout time		*/
X
X  struct logout *next;		/*  Next in linked list		*/
X  } logout;
X
X
X
X/****************************************************************/
X/*								*/
X/*	last [-r] [-count] [-f file] [name] [tty] ...		*/
X/*								*/
X/*								*/
X/*	Last(1) searches backwards through the file of log-in 	*/
X/*	records (/usr/adm/wtmp), displaying the length of 	*/
X/*	log-in sessions as requested by the options:		*/
X/*								*/
X/*								*/
X/*	-r	Search backwards only until the last reboot	*/
X/*		record.						*/
X/*								*/
X/*	-count	Only print out <count> records. Last(1) stops	*/
X/*		when either -r or -count is satisfied, or at	*/
X/*		the end of the file if neither is given.	*/
X/*								*/
X/*	-f file	Use "file" instead of "/usr/adm/wtmp".		*/
X/*								*/
X/*	name	Print records for the user "name".		*/
X/*								*/
X/*	tty	Print records for the terminal "tty". Actually,	*/
X/*		a list of names may be given and all records	*/
X/*		that match either the user or tty name are	*/
X/*		printed. If no names are given then all records	*/
X/*		are displayed.					*/
X/*								*/
X/*								*/
X/*	A sigquit (^\) causes last(1) to display how far it	*/
X/*	has gone back in the log-in record file, it then 	*/
X/*	continues. This is used to check on the progress of	*/
X/*	long running searches. A sigint will stop last(1).	*/
X/*								*/
X/****************************************************************/
X
X
X
X/****************************************************************/
X/*		Command-line option flags			*/
X/****************************************************************/
X
X
Xchar    boot_limit   = FALSE;	/*  Stop on latest reboot	*/
Xchar    count_limit  = FALSE;	/*  Stop after print_count	*/
Xint     print_count;
Xint     arg_count;		/*  Used to select specific	*/
Xchar  **args;			/*  users and ttys		*/
X
X
X
X/****************************************************************/
X/*		Global variables				*/
X/****************************************************************/
X
X
Xlong    boot_time    = 0;	/*  Zero means no reboot yet	*/
Xchar   *boot_down;		/*  "crash" or "down " flag	*/
Xlogout *first_link   = NULL;	/*  List of logout times	*/
Xint     interrupt    = FALSE;	/*  If sigint or sigquit occurs	*/
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	main()							*/
X/*								*/
X/****************************************************************/
X
X
Xmain( argc, argv )
X  int argc;
X  char *argv[];
X
X  {
X  char  *wtmp_file = WTMP;
X  FILE  *f;
X  long   size;		/*  Number of wtmp records in the file	*/
X  int    wtmp_count;	/*  How many to read into wtmp_buffer	*/
X  struct utmp  wtmp_buffer[ MAX_WTMP_COUNT ];
X
X
X  --argc;
X  ++argv;
X
X  while (  argc > 0  &&  *argv[0] == '-'  )
X    {
X    if (  strcmp( argv[0], "-r" ) == 0  )
X	boot_limit = TRUE;
X
X    else if (  argc > 1  &&  strcmp( argv[0], "-f" ) == 0  )
X	{
X	wtmp_file = argv[1];
X	--argc;
X	++argv;
X	}
X
X    else if ( (print_count = atoi( argv[0]+1 )) > 0 )
X	count_limit = TRUE;
X
X    else
X	{
X	fprintf( stderr, "Usage: last [-r] [-count] [-f file] [name] [tty] ...\n" );
X	exit( 1 );
X	}
X
X    --argc;
X    ++argv;
X    }
X
X
X  arg_count = argc;
X  args      = argv;
X
X
X
X  if( (f = fopen( wtmp_file, "r" )) == NULL )
X    {
X    perror( wtmp_file );
X    exit( 1 );
X    }
X
X  if ( fseek( f, 0L, 2 ) != 0  ||  (size = ftell(f)) % sizeof(struct utmp) != 0 )
X    {
X    fprintf( stderr, "last: invalid wtmp file\n" );
X    exit( 1 );
X    }
X
X
X  if ( signal( SIGINT, SIG_IGN ) != SIG_IGN )
X    {
X    signal( SIGINT,  Sigint  );
X    signal( SIGQUIT, Sigquit );
X    }
X
X
X
X  size /= sizeof(struct utmp);	/*  Number of records in wtmp	*/
X
X  if ( size == 0 )
X    {
X    long now = time( 0 );
X
X    printf( "\nwtmp begins %.16s \n", ctime( &now ) );
X    exit( 0 );
X    }
X
X
X  while( size > 0 )
X    {
X    wtmp_count = (int) min( size, MAX_WTMP_COUNT );
X
X    size -= (long) wtmp_count;
X
X    fseek( f, size * sizeof(struct utmp), 0 );
X
X
X    if ( fread( &wtmp_buffer[ 0 ], sizeof(struct utmp), wtmp_count, f ) != wtmp_count )
X	{
X    	fprintf( stderr, "last: read error on wtmp file\n" );
X    	exit( 1 );
X    	}
X
X
X    while ( --wtmp_count >= 0 )
X	{
X	Process( &wtmp_buffer[ wtmp_count ] );
X     
X	if ( interrupt )
X	  {
X      	  printf( "\ninterrupted %.16s \n",
X		ctime( &wtmp_buffer[ wtmp_count ].ut_time ) );
X
X    	  if ( interrupt == SIGINT )
X      	      exit( 2 );
X
X	  interrupt = FALSE;
X	  signal( SIGQUIT, Sigquit );
X	  }
X	}
X
X    }  /* end while( size > 0 ) */
X
X  printf( "\nwtmp begins %.16s \n", ctime( &wtmp_buffer[ 0 ].ut_time ) );
X  exit( 0 );
X  }
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	A log-in record format file contains four types of	*/
X/*	records.						*/
X/*								*/
X/*	  [1] generated on a system reboot:			*/
X/*								*/
X/*	   line="~", name="reboot", host="", time=date()	*/
X/*								*/
X/*								*/
X/*	  [2] generated after a shutdown:			*/
X/*								*/
X/*	   line="~", name="shutdown", host="", time=date()	*/
X/*								*/
X/*								*/
X/*	  [3] generated on a successful login(1)		*/
X/*								*/
X/*	   line=ttyname(), name=cuserid(), host=, time=date()	*/
X/*								*/
X/*								*/
X/*	  [4] generated by init(8) on a logout			*/
X/*								*/
X/*	   line=ttyname(), name="", host="", time=date()	*/
X/*								*/
X/*								*/
X/*	Note: This version of last(1) does not recognize the	*/
X/*	'|' and '}' time change records.			*/
X/*								*/
X/****************************************************************/
X/*								*/
X/*	Last(1) pairs up line login's and logout's to generate	*/
X/*	four types of output lines:				*/
X/*								*/
X/*	  [1] a system reboot or shutdown			*/
X/*								*/
X/*	   reboot    ~       Mon May 16 14:16 			*/
X/*	   shutdown  ~       Mon May 16 14:15 			*/
X/*								*/
X/*								*/
X/*	  [2] a login with a matching logout			*/
X/*								*/
X/*	   edwin     tty1    Thu May 26 20:05 - 20:32  (00:27)	*/
X/*								*/
X/*								*/
X/*	  [3] a login followed by a reboot or shutdown		*/
X/*								*/
X/*	   root      tty0    Mon May 16 13:57 - crash  (00:19)	*/
X/*	   root      tty1    Mon May 16 13:45 - down   (00:30)	*/
X/*								*/
X/*								*/
X/*	  [4] a login not followed by a logout or reboot	*/
X/*								*/
X/*	   terry     tty0    Thu May 26 21:19   still logged in	*/
X/*								*/
X/****************************************************************/
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	Process( wtmp )						*/
X/*								*/
X/*		Interpret one record from the log-in record	*/
X/*		file.						*/
X/*								*/
X/****************************************************************/
X
X
XProcess( wtmp )
X  struct utmp *wtmp;
X
X  {
X  logout *link;
X  logout *next_link;
X
X
X  /*  Suppress the job number on an "ftp" line  */
X
X  if ( strncmp( wtmp->ut_line, "ftp", 3 ) == 0 )
X      strncpy( wtmp->ut_line, "ftp", 8 );
X
X
X  if ( strcmp( wtmp->ut_line, "~" ) == 0 )
X    {
X    /*  A reboot or shutdown record  */
X
X    if ( boot_limit )
X	exit( 0 );
X
X    if ( Print_Record( wtmp ) )
X    	putchar( '\n' );
X
X    boot_time = wtmp->ut_time;
X
X    if ( strcmp( wtmp->ut_name, "reboot" ) == 0 )
X	boot_down = "crash";
X    else
X	boot_down = "down ";
X
X
X    /*  Remove any logout records  */
X
X    for( link = first_link;  link != NULL;  link = next_link )
X      	{
X      	next_link = link->next;
X      	free( link );
X      	}
X
X    first_link = NULL;
X    }
X
X
X  else if ( wtmp->ut_name[0] == '\0' )
X    {
X    /*  A logout record  */
X
X    Record_Logout_Time( wtmp );
X    }
X
X
X  else
X    {
X    /*  A login record  */
X
X    for( link = first_link;  link != NULL;  link = link->next )
X      if ( strncmp( link->line, wtmp->ut_line, 8 ) == 0 )
X	{
X	/*  Found corresponding logout record  */
X
X	if ( Print_Record( wtmp ) )
X	    {
X	    printf( "- %.5s ", ctime( &link->time )+11 );
X
X  	    Print_Duration( wtmp->ut_time, link->time );
X	    }
X
X	/*  Record login time  */
X	link->time = wtmp->ut_time;
X	return;
X	}
X
X
X    /*  Could not find a logout record for this login tty  */
X
X    if ( Print_Record( wtmp ) )
X    	if ( boot_time == 0 )    /*  Still on  */
X	    printf( "  still logged in\n" );
X
X        else 	    /*  System crashed while on  */
X	    {
X	    printf( "- %s ", boot_down );
X
X	    Print_Duration( wtmp->ut_time, boot_time );
X	    }
X
X    Record_Logout_Time( wtmp );  /*  Needed in case of 2 consecutive logins  */
X    }
X  }
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	Print_Record( wtmp )					*/
X/*								*/
X/*		If the record was requested, then print out	*/
X/*		the user name, terminal, host and time.		*/
X/*								*/
X/****************************************************************/
X
X
XPrint_Record( wtmp )
X  struct utmp *wtmp;
X
X  {
X  int  i;
X  char print_flag = FALSE;
X
X  /*  Check if we have already printed the requested number of records  */
X
X  if (  count_limit  &&  print_count == 0 )
X    exit( 0 );
X
X  for ( i = 0;  i < arg_count  ; ++i )
X    if ( strcmp( args[i], wtmp->ut_name ) == 0  ||
X         strcmp( args[i], wtmp->ut_line ) == 0  )
X		print_flag = TRUE;
X
X  if (  arg_count == 0  ||  print_flag  )
X    {
X#ifdef RLOGIN
X    printf( "%-8.8s  %-8.8s %-16.16s %.16s ",
X        wtmp->ut_name, wtmp->ut_line, wtmp->ut_host, ctime( &wtmp->ut_time ) );
X#else
X    printf( "%-8.8s  %-8.8s  %.16s ",
X        wtmp->ut_name, wtmp->ut_line, ctime( &wtmp->ut_time ) );
X#endif
X
X    --print_count;
X    return( TRUE );
X    }
X
X  return( FALSE );
X  }
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	Print_Duration( from, to )				*/
X/*								*/
X/*		Calculate and print the days and hh:mm between	*/
X/*		the log-in and the log-out.			*/
X/*								*/
X/****************************************************************/
X
X
XPrint_Duration( from, to )
X  long from;
X  long to;
X
X  {
X  long delta, days, hours, minutes;
X
X  delta   = max( to - from, 0 );
X  days    = delta / (24L * 60L * 60L);
X  delta   = delta % (24L * 60L * 60L);
X  hours   = delta / (60L * 60L);
X  delta   = delta % (60L * 60L);
X  minutes = delta / 60L;
X
X  if ( days > 0 )
X    printf( "(%D+", days );
X  else
X    printf( " (" );
X
X  printf( "%02D:%02D)\n", hours, minutes );
X  }
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	Record_Logout_Time( wtmp )				*/
X/*								*/
X/*		A linked list of "last logout time" is kept.	*/
X/*		Each element of the list is for one terminal.	*/
X/*								*/
X/****************************************************************/
X
X
XRecord_Logout_Time( wtmp )
X  struct utmp *wtmp;
X
X  {
X  logout *link;
X
X  /*  See if the terminal is already in the list  */
X
X  for( link = first_link;  link != NULL;  link = link->next )
X    if ( strncmp( link->line, wtmp->ut_line, 8 ) == 0 )
X	{
X	link->time = wtmp->ut_time;
X	return;
X	}
X
X  /*  Allocate a new logout record, for a tty not previously encountered  */
X
X  link = (logout *) malloc( sizeof( logout ) );
X
X  if ( link == (logout *) NULL )
X    {
X    fprintf( stderr, "last: malloc failure\n" );
X    exit( 1 );
X    }
X
X  strncpy( link->line, wtmp->ut_line, 8 );
X
X  link->time = wtmp->ut_time;
X  link->next = first_link;
X
X  first_link = link;
X  }
X
X
X
X
X/****************************************************************/
X/*								*/
X/*	Sigint()						*/
X/*	Sigquit()						*/
X/*								*/
X/*		Flag occurrence of an interrupt.		*/
X/*								*/
X/****************************************************************/
X
X
XSigint()
X  {
X  interrupt = SIGINT;
X  }
X
X
X
XSigquit()
X  {
X  interrupt = SIGQUIT;
X  }
/
echo x - last.1
gres '^X' '' > last.1 << '/'
XNAME
X    last(1)		- display on-line session records
X
XSYNOPSIS
X    last  [-r]  [-count]  [-f file]  [name]  [tty]  ...
X
XDESCRIPTION
X    Last(1) searches backwards through the file of log-in
X    records displaying the length of sessions as requested
X    by the options:
X
X      -r	Search backwards only until the last reboot
X		record.
X
X      -count	Only print out <count> records. Last(1) stops
X		when either -r or -count is satisfied, or at
X		the end of the file if neither is given.
X
X      -f file	Use "file" instead of "/usr/adm/wtmp".
X
X      name	Print records for the user "name".
X
X      tty	Print records for the terminal "tty". Actually,
X		a list of names may be given and all records
X		that match either the user or tty name are
X		printed. If no names are given then all records
X		are displayed.
X
X    A sigquit (^\) causes last(1) to display how far it has gone
X    back in the log-in record file, it then continues. This is
X    used to check on the progress of long running searches. A
X    sigint will stop last(1).
X
XEXAMPLES
X    When has the system been rebooted?
X
X	last reboot
X
X    When was my last login?
X
X	last -2 $USER
X
X    Show me the last ten times someone logged onto /dev/tty0
X    or /dev/tty1:
X
X	last -10 tty0 tty1
X
XFILES
X    /usr/adm/wtmp		on-line session records
X
XSEE ALSO
X    login(1), who(1), utmp(4)
/
echo x - who.c
gres '^X' '' > who.c << '/'
X/* who(1)		Who is logged on?
X *
X * Author: Terrence W. Holm	June 1988
X *
X *
X *  who
X *  who <USER>
X *  who <DEVICE>
X *  who am i
X *
X * The user log-in name, terminal port and log-in time
X * are displayed for all current users, or restricted
X * to the specified <USER>, <DEVICE> or the current user.
X */
X
X
X#include <stdio.h>
X
X#define  LINE_SIZE  80   /*  Max. line size from last(1)  */
X
Xchar *ttyname();
XFILE *fdopen();
X
X
Xmain( argc, argv )
X  int   argc;
X  char *argv[];
X
X  {
X  char *argument;
X  int   desc[2];
X  int   pid;
X  FILE *f;
X  char  line[ LINE_SIZE ];
X
X  if ( argc == 1 )
X    argument = NULL;
X
X  else if ( argc == 2 )
X    argument = argv[1];
X
X  else if ( argc == 3  &&  strcmp(argv[1],"am") == 0  &&
X     ( strcmp(argv[2],"i") == 0  ||  strcmp(argv[2],"I") == 0 ) )
X    argument = ttyname(0) + 5;
X
X  else
X    {
X    fprintf( stderr, "Usage:  who  [  USER  |  DEVICE  |  am i  ]\n" );
X    exit( 1 );
X    }
X
X
X  /*  Create a child process to execute last(1)  */
X
X  if ( pipe( desc ) == -1 )
X    exit( 1 );
X
X  if ( (pid = fork()) == -1 )
X    exit( 1 );
X
X  if ( pid == 0 )
X    {
X    /*  The child process  */
X
X    dup2( desc[1], 1 );
X    close( desc[0] );
X    close( desc[1] );
X
X    execlp( "last", "last", "-r", argument, (char *) 0 );
X    perror( "last" );
X    exit( 127 );
X    }
X
X
X  /*  The parent process: read the standard output from last(1)  */
X
X  close( desc[1] );
X  f = fdopen( desc[0], "r" );
X
X  while ( fgets( line, LINE_SIZE, f ) != NULL )
X    if ( line[strlen(line) - 2]  == 'n' )
X#ifdef RLOGIN
X	printf( "%.18s %.12s   %.16s\n", line, line + 40, line + 19 );
X#else
X	printf( "%.18s %.12s\n", line, line + 24 );
X#endif
X
X  exit( 0 );
X  }
/
echo x - who.1
gres '^X' '' > who.1 << '/'
XNAME
X    who(1)		- who is currently on the system
X
XSYNOPSIS
X    who  [  user  |  device  |  am i  ]
X
XDESCRIPTION
X    If no options are given then who(1) displays the name,
X    terminal port and log-in time for all of the present
X    users.
X
X    A "user" or "device" name checks for a current log-in
X    by the "user" or at the "device". The command "who am I"
X    only reports on the current session.
X
XFILES
X    /usr/adm/wtmp
X
XSEE ALSO
X    last(1), whoami(1)
/
----------------------------------------------------------