Minix1.5/commands/last.c
/* last - display login history Author: Terrence W. Holm */
/* last- Display the user log-in history.
* Last(1) searches backwards through the file of log-in
* records (/usr/adm/wtmp), displaying the length of
* log-in sessions as requested by the options:
*
* Usage: last [-r] [-count] [-f file] [name] [tty] ...
*
* -r Search backwards only until the last reboot
* record.
*
* -count Only print out <count> records. Last(1) stops
* when either -r or -count is satisfied, or at
* the end of the file if neither is given.
*
* -f file Use "file" instead of "/usr/adm/wtmp".
*
* name Print records for the user "name".
*
* tty Print records for the terminal "tty". Actually,
* a list of names may be given and all records
* that match either the user or tty name are
* printed. If no names are given then all records
* are displayed.
*
* A sigquit (^\) causes last(1) to display how far it
* has gone back in the log-in record file, it then
* continues. This is used to check on the progress of
* long running searches. A sigint will stop last(1).
*
* Author: Terrence W. Holm May 1988
*
* Revision:
* Fred van Kempen, October 1989
* -Adapted to MSS.
* -Adapted to new utmp database.
*
* Fred van Kempen, December 1989
* -Adapted to POSIX (MINIX 1.5)
*
* Fred van Kempen, January 1990
* -Final edit for 1.5
*/
#include <sys/types.h>
#include <signal.h>
#include <string.h>
#include <utmp.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#define FALSE 0
#define TRUE 1
#define BUFFER_SIZE 4096 /* Room for wtmp records */
#define MAX_WTMP_COUNT ( BUFFER_SIZE / sizeof(struct utmp) )
#define min( a, b ) ( (a < b) ? a : b )
#define max( a, b ) ( (a > b) ? a : b )
typedef struct logout { /* A logout time record */
char line[12]; /* The terminal name */
long time; /* The logout time */
struct logout *next; /* Next in linked list */
} logout;
static char *Version = "@(#) LAST 1.6 (01/09/90)";
/* command-line option flags */
char boot_limit = FALSE; /* stop on latest reboot */
char count_limit = FALSE; /* stop after print_count */
int print_count;
int arg_count; /* used to select specific */
char **args; /* users and ttys */
/* global variables */
long boot_time = 0; /* Zero means no reboot yet */
char *boot_down; /* "crash" or "down " flag */
logout *first_link = NULL; /* List of logout times */
int interrupt = FALSE; /* If sigint or sigquit occurs */
/* Sigint() and Sigquit() Flag occurrence of an interrupt. */
void Sigint(sig)
int sig;
{
interrupt = SIGINT;
}
void Sigquit(sig)
int sig;
{
interrupt = SIGQUIT;
}
void usage()
{
fprintf(stderr, "Usage: last [-r] [-count] [-f file] [name] [tty] ...\n");
exit(-1);
}
/* A log-in record format file contains four types of records.
*
* [1] generated on a system reboot:
*
* line="~", name="reboot", host="", time=date()
*
*
* [2] generated after a shutdown:
*
* line="~", name="shutdown", host="", time=date()
*
*
* [3] generated on a successful login(1)
*
* line=ttyname(), name=cuserid(), host=, time=date()
*
*
* [4] generated by init(8) on a logout
*
* line=ttyname(), name="", host="", time=date()
*
*
* Note: This version of last(1) does not recognize the '|' and '}' time
* change records. Last(1) pairs up line login's and logout's to
* generate four types of output lines:
*
* [1] a system reboot or shutdown
*
* reboot ~ Mon May 16 14:16
* shutdown ~ Mon May 16 14:15
*
* [2] a login with a matching logout
*
* edwin tty1 Thu May 26 20:05 - 20:32 (00:27)
*
* [3] a login followed by a reboot or shutdown
*
* root tty0 Mon May 16 13:57 - crash (00:19)
* root tty1 Mon May 16 13:45 - down (00:30)
*
* [4] a login not followed by a logout or reboot
*
* terry tty0 Thu May 26 21:19 still logged in
*/
Process(wtmp)
struct utmp *wtmp;
{
logout *link;
logout *next_link;
/* suppress the job number on an "ftp" line */
if (!strncmp(wtmp->ut_line, "ftp", 3)) strncpy(wtmp->ut_line, "ftp", 8);
if (!strcmp(wtmp->ut_line, "~")) {
/* A reboot or shutdown record */
if (boot_limit) exit(0);
if (Print_Record(wtmp)) putchar('\n');
boot_time = wtmp->ut_time;
if (!strcmp(wtmp->ut_name, "reboot"))
boot_down = "crash";
else
boot_down = "down ";
/* remove any logout records */
for (link = first_link; link != NULL; link = next_link) {
next_link = link->next;
free(link);
}
first_link = NULL;
} else if (wtmp->ut_name[0] == '\0') {
/* A logout record */
Record_Logout_Time(wtmp);
} else {
/* A login record */
for (link = first_link; link != NULL; link = link->next)
if (!strncmp(link->line, wtmp->ut_line, 8)) {
/* found corresponding logout record */
if (Print_Record(wtmp)) {
printf("- %.5s ", ctime(&link->time) + 11);
Print_Duration(wtmp->ut_time, link->time);
}
/* record login time */
link->time = wtmp->ut_time;
return;
}
/* could not find a logout record for this login tty */
if (Print_Record(wtmp))
if (boot_time == 0) /* still on */
printf(" still logged in\n");
else { /* system crashed while on */
printf("- %s ", boot_down);
Print_Duration(wtmp->ut_time, boot_time);
}
Record_Logout_Time(wtmp); /* Needed in case of 2
* consecutive logins */
}
}
/* Print_Record(wtmp) If the record was requested, then print out
* the user name, terminal, host and time.
*/
Print_Record(wtmp)
struct utmp *wtmp;
{
int i;
char print_flag = FALSE;
/* check if we have already printed the requested number of records */
if (count_limit && print_count == 0) exit(0);
for (i = 0; i < arg_count; ++i)
if (!strcmp(args[i], wtmp->ut_name) || !strcmp(args[i], wtmp->ut_line))
print_flag = TRUE;
if (arg_count == 0 || print_flag) {
#ifdef RLOGIN
printf("%-8.8s %-8.8s %-16.16s %.16s ",
wtmp->ut_name, wtmp->ut_line, wtmp->ut_host,
ctime(&wtmp->ut_time));
#else
printf("%-8.8s %-8.8s %.16s ",
wtmp->ut_name, wtmp->ut_line, ctime(&wtmp->ut_time));
#endif
--print_count;
return(TRUE);
}
return(FALSE);
}
/* Print_Duration(from, to) Calculate and print the days and hh:mm between
* the log-in and the log-out.
*/
Print_Duration(from, to)
long from;
long to;
{
long delta, days, hours, minutes;
delta = max(to - from, 0);
days = delta / (24L * 60L * 60L);
delta = delta % (24L * 60L * 60L);
hours = delta / (60L * 60L);
delta = delta % (60L * 60L);
minutes = delta / 60L;
if (days > 0)
printf("(%ld+", days);
else
printf(" (");
printf("%02ld:%02ld)\n", hours, minutes);
}
/* Record_Logout_Time(wtmp) A linked list of "last logout time" is kept.
* Each element of the list is for one terminal.
*/
Record_Logout_Time(wtmp)
struct utmp *wtmp;
{
logout *link;
/* see if the terminal is already in the list */
for (link = first_link; link != NULL; link = link->next)
if (!strncmp(link->line, wtmp->ut_line, 8)) {
link->time = wtmp->ut_time;
return;
}
/* allocate a new logout record, for a tty not previously encountered */
link = (logout *) malloc(sizeof(logout));
if (link == (logout *) NULL) {
fprintf(stderr, "last: malloc failure\n");
exit(1);
}
strncpy(link->line, wtmp->ut_line, 8);
link->time = wtmp->ut_time;
link->next = first_link;
first_link = link;
}
main(argc, argv)
int argc;
char *argv[];
{
char *wtmp_file = WTMP;
FILE *f;
long size; /* Number of wtmp records in the file */
long now; /* time */
int wtmp_count; /* How many to read into wtmp_buffer */
struct utmp wtmp_buffer[MAX_WTMP_COUNT];
--argc;
++argv;
while (argc > 0 && *argv[0] == '-') {
if (!strcmp(argv[0], "-r"))
boot_limit = TRUE;
else if (argc > 1 && !strcmp(argv[0], "-f")) {
wtmp_file = argv[1];
--argc;
++argv;
} else if ((print_count = atoi(argv[0] + 1)) > 0)
count_limit = TRUE;
else
usage();
--argc;
++argv;
}
arg_count = argc;
args = argv;
if ((f = fopen(wtmp_file, "r")) == (FILE *) NULL) {
perror(wtmp_file);
exit(1);
}
if (fseek(f, 0L, 2) != 0 || (size = ftell(f)) % sizeof(struct utmp) != 0) {
fprintf(stderr, "last: invalid wtmp file\n");
exit(1);
}
if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
signal(SIGINT, Sigint);
signal(SIGQUIT, Sigquit);
}
size /= sizeof(struct utmp); /* Number of records in wtmp */
if (size == 0) {
now = time((time_t *)0);
printf("\nwtmp begins %.16s \n", ctime(&now));
exit(0);
}
while (size > 0) {
wtmp_count = (int) min(size, MAX_WTMP_COUNT);
size -= (long) wtmp_count;
fseek(f, size * sizeof(struct utmp), 0);
if (fread(&wtmp_buffer[0], sizeof(struct utmp), wtmp_count, f)
!= wtmp_count) {
fprintf(stderr, "last: read error on wtmp file\n");
exit(1);
}
while (--wtmp_count >= 0) {
Process(&wtmp_buffer[wtmp_count]);
if (interrupt) {
printf("\ninterrupted %.16s \n",
ctime(&wtmp_buffer[wtmp_count].ut_time));
if (interrupt == SIGINT) exit(2);
interrupt = FALSE;
signal(SIGQUIT, Sigquit);
}
}
} /* end while(size > 0) */
printf("\nwtmp begins %.16s \n", ctime(&wtmp_buffer[0].ut_time));
exit(0);
}