blob: 5bf48ecdaf5b76e349c230e55c6e17816c32e5e1 [file] [log] [blame] [raw]
/*
* last.c Re-implementation of the 'last' command, this time
* for Linux. Yes I know there is BSD last, but I
* just felt like writing this. No thanks :-).
* Also, this version gives lots more info (especially with -x)
*
* Author: Miquel van Smoorenburg, miquels@cistron.nl
*
* Version: @(#)last 2.85 30-Jul-2004 miquels@cistron.nl
*
* This file is part of the sysvinit suite,
* Copyright (C) 1991-2004 Miquel van Smoorenburg.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <time.h>
#include <stdio.h>
#include <ctype.h>
#include <utmp.h>
#include <errno.h>
#include <malloc.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <getopt.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include "oldutmp.h"
#ifndef SHUTDOWN_TIME
# define SHUTDOWN_TIME 254
#endif
char *Version = "@(#) last 2.85 31-Apr-2004 miquels";
#define CHOP_DOMAIN 0 /* Define to chop off local domainname. */
#define NEW_UTMP 1 /* Fancy & fast utmp read code. */
#define UCHUNKSIZE 16384 /* How much we read at once. */
/* Double linked list of struct utmp's */
struct utmplist {
struct utmp ut;
struct utmplist *next;
struct utmplist *prev;
};
struct utmplist *utmplist = NULL;
/* Types of listing */
#define R_CRASH 1 /* No logout record, system boot in between */
#define R_DOWN 2 /* System brought down in decent way */
#define R_NORMAL 3 /* Normal */
#define R_NOW 4 /* Still logged in */
#define R_REBOOT 5 /* Reboot record. */
#define R_PHANTOM 6 /* No logout record but session is stale. */
#define R_TIMECHANGE 7 /* NEW_TIME or OLD_TIME */
/* Global variables */
int maxrecs = 0; /* Maximum number of records to list. */
int recsdone = 0; /* Number of records listed */
int showhost = 1; /* Show hostname too? */
int altlist = 0; /* Show hostname at the end. */
int usedns = 0; /* Use DNS to lookup the hostname. */
int useip = 0; /* Print IP address in number format */
int fulltime = 0; /* Print full dates and times */
int oldfmt = 0; /* Use old libc5 format? */
char **show = NULL; /* What do they want us to show */
char *ufile; /* Filename of this file */
time_t lastdate; /* Last date we've seen */
char *progname; /* Name of this program */
#if CHOP_DOMAIN
char hostname[256]; /* For gethostbyname() */
char *domainname; /* Our domainname. */
#endif
/*
* Convert old utmp format to new.
*/
void uconv(struct oldutmp *oldut, struct utmp *utn)
{
memset(utn, 0, sizeof(struct utmp));
utn->ut_type = oldut->ut_type;
utn->ut_pid = oldut->ut_pid;
utn->ut_time = oldut->ut_oldtime;
utn->ut_addr = oldut->ut_oldaddr;
strncpy(utn->ut_line, oldut->ut_line, OLD_LINESIZE);
strncpy(utn->ut_user, oldut->ut_user, OLD_NAMESIZE);
strncpy(utn->ut_host, oldut->ut_host, OLD_HOSTSIZE);
}
#if NEW_UTMP
/*
* Read one utmp entry, return in new format.
* Automatically reposition file pointer.
*/
int uread(FILE *fp, struct utmp *u, int *quit)
{
static int utsize;
static char buf[UCHUNKSIZE];
char tmp[1024];
static off_t fpos;
static int bpos;
struct oldutmp uto;
int r;
off_t o;
if (quit == NULL && u != NULL) {
/*
* Normal read.
*/
if (oldfmt) {
r = fread(&uto, sizeof(uto), 1, fp);
uconv(&uto, u);
} else
r = fread(u, sizeof(struct utmp), 1, fp);
return r;
}
if (u == NULL) {
/*
* Initialize and position.
*/
utsize = oldfmt ? sizeof(uto) : sizeof(struct utmp);
fseeko(fp, 0, SEEK_END);
fpos = ftello(fp);
if (fpos == 0)
return 0;
o = ((fpos - 1) / UCHUNKSIZE) * UCHUNKSIZE;
if (fseeko(fp, o, SEEK_SET) < 0) {
fprintf(stderr, "%s: seek failed!\n", progname);
return 0;
}
bpos = (int)(fpos - o);
if (fread(buf, bpos, 1, fp) != 1) {
fprintf(stderr, "%s: read failed!\n", progname);
return 0;
}
fpos = o;
return 1;
}
/*
* Read one struct. From the buffer if possible.
*/
bpos -= utsize;
if (bpos >= 0) {
if (oldfmt)
uconv((struct oldutmp *)(buf + bpos), u);
else
memcpy(u, buf + bpos, sizeof(struct utmp));
return 1;
}
/*
* Oops we went "below" the buffer. We should be able to
* seek back UCHUNKSIZE bytes.
*/
fpos -= UCHUNKSIZE;
if (fpos < 0)
return 0;
/*
* Copy whatever is left in the buffer.
*/
memcpy(tmp + (-bpos), buf, utsize + bpos);
if (fseeko(fp, fpos, SEEK_SET) < 0) {
perror("fseek");
return 0;
}
/*
* Read another UCHUNKSIZE bytes.
*/
if (fread(buf, UCHUNKSIZE, 1, fp) != 1) {
perror("fread");
return 0;
}
/*
* The end of the UCHUNKSIZE byte buffer should be the first
* few bytes of the current struct utmp.
*/
memcpy(tmp, buf + UCHUNKSIZE + bpos, -bpos);
bpos += UCHUNKSIZE;
if (oldfmt)
uconv((struct oldutmp *)tmp, u);
else
memcpy(u, tmp, sizeof(struct utmp));
return 1;
}
#else /* NEW_UTMP */
/*
* Read one utmp entry, return in new format.
* Automatically reposition file pointer.
*/
int uread(FILE *fp, struct utmp *u, int *quit)
{
struct oldutmp uto;
off_t r;
if (u == NULL) {
r = oldfmt ? sizeof(struct oldutmp) : sizeof(struct utmp);
fseek(fp, -1 * r, SEEK_END);
return 1;
}
if (!oldfmt) {
r = fread(u, sizeof(struct utmp), 1, fp);
if (r == 1) {
if (fseeko(fp, -2 * sizeof(struct utmp), SEEK_CUR) < 0)
if (quit) *quit = 1;
}
return r;
}
r = fread(&uto, sizeof(struct oldutmp), 1, fp);
if (r == 1) {
if (fseeko(fp, -2 * sizeof(struct oldutmp), SEEK_CUR) < 0)
if (quit) *quit = 1;
uconv(&uto, u);
}
return r;
}
#endif
/*
* Try to be smart about the location of the BTMP file
*/
#ifndef BTMP_FILE
#define BTMP_FILE getbtmp()
char *getbtmp()
{
static char btmp[128];
char *p;
strcpy(btmp, WTMP_FILE);
if ((p = strrchr(btmp, '/')) == NULL)
p = btmp;
else
p++;
*p = 0;
strcat(btmp, "btmp");
return btmp;
}
#endif
/*
* Print a short date.
*/
char *showdate()
{
char *s = ctime(&lastdate);
s[16] = 0;
return s;
}
/*
* SIGINT handler
*/
void int_handler()
{
printf("Interrupted %s\n", showdate());
exit(1);
}
/*
* SIGQUIT handler
*/
void quit_handler()
{
printf("Interrupted %s\n", showdate());
signal(SIGQUIT, quit_handler);
}
/*
* Get the basename of a filename
*/
char *mybasename(char *s)
{
char *p;
if ((p = strrchr(s, '/')) != NULL)
p++;
else
p = s;
return p;
}
/*
* Lookup a host with DNS.
*/
int dns_lookup(char *result, int size, int useip, int32_t *a)
{
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct sockaddr *sa;
int salen, flags;
unsigned int topnibble;
unsigned int azero = 0, sitelocal = 0;
int mapped = 0;
flags = useip ? NI_NUMERICHOST : 0;
/*
* IPv4 or IPv6 ? We use 2 heuristics:
* 1. Current IPv6 range uses 2000-3fff or fec0-feff.
* Outside of that is illegal and must be IPv4.
* 2. If last 3 bytes are 0, must be IPv4
* 3. If IPv6 in IPv4, handle as IPv4
*
* Ugly.
*/
if (a[0] == 0 && a[1] == 0 && a[2] == htonl (0xffff))
mapped = 1;
topnibble = ntohl((unsigned int)a[0]) >> 28;
azero = ntohl((unsigned int)a[0]) >> 16;
sitelocal = (azero >= 0xfec0 && azero <= 0xfeff) ? 1 : 0;
if (((topnibble < 2 || topnibble > 3) && (!sitelocal)) || mapped ||
(a[1] == 0 && a[2] == 0 && a[3] == 0)) {
/* IPv4 */
sin.sin_family = AF_INET;
sin.sin_port = 0;
sin.sin_addr.s_addr = mapped ? a[3] : a[0];
sa = (struct sockaddr *)&sin;
salen = sizeof(sin);
} else {
/* IPv6 */
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
sin6.sin6_port = 0;
memcpy(sin6.sin6_addr.s6_addr, a, 16);
sa = (struct sockaddr *)&sin6;
salen = sizeof(sin6);
}
return getnameinfo(sa, salen, result, size, NULL, 0, flags);
}
/*
* Show one line of information on screen
*/
int list(struct utmp *p, time_t t, int what)
{
time_t secs, tmp;
char logintime[32];
char logouttime[32];
char length[32];
char final[128];
char utline[UT_LINESIZE+1];
char domain[256];
char *s, **walk;
int mins, hours, days;
int r, len;
/*
* uucp and ftp have special-type entries
*/
utline[0] = 0;
strncat(utline, p->ut_line, UT_LINESIZE);
if (strncmp(utline, "ftp", 3) == 0 && isdigit(utline[3]))
utline[3] = 0;
if (strncmp(utline, "uucp", 4) == 0 && isdigit(utline[4]))
utline[4] = 0;
/*
* Is this something we wanna show?
*/
if (show) {
for (walk = show; *walk; walk++) {
if (strncmp(p->ut_name, *walk, UT_NAMESIZE) == 0 ||
strcmp(utline, *walk) == 0 ||
(strncmp(utline, "tty", 3) == 0 &&
strcmp(utline + 3, *walk) == 0)) break;
}
if (*walk == NULL) return 0;
}
/*
* Calculate times
*/
tmp = (time_t)p->ut_time;
strcpy(logintime, ctime(&tmp));
if (fulltime)
sprintf(logouttime, "- %s", ctime(&t));
else {
logintime[16] = 0;
sprintf(logouttime, "- %s", ctime(&t) + 11);
logouttime[7] = 0;
}
secs = t - p->ut_time;
mins = (secs / 60) % 60;
hours = (secs / 3600) % 24;
days = secs / 86400;
if (days)
sprintf(length, "(%d+%02d:%02d)", days, hours, mins);
else
sprintf(length, " (%02d:%02d)", hours, mins);
switch(what) {
case R_CRASH:
sprintf(logouttime, "- crash");
break;
case R_DOWN:
sprintf(logouttime, "- down ");
break;
case R_NOW:
length[0] = 0;
if (fulltime)
sprintf(logouttime, " still logged in");
else {
sprintf(logouttime, " still");
sprintf(length, "logged in");
}
break;
case R_PHANTOM:
length[0] = 0;
if (fulltime)
sprintf(logouttime, " gone - no logout");
else {
sprintf(logouttime, " gone");
sprintf(length, "- no logout");
}
break;
case R_REBOOT:
break;
case R_TIMECHANGE:
logouttime[0] = 0;
length[0] = 0;
break;
case R_NORMAL:
break;
}
/*
* Look up host with DNS if needed.
*/
r = -1;
if (usedns || useip)
r = dns_lookup(domain, sizeof(domain), useip, p->ut_addr_v6);
if (r < 0) {
len = UT_HOSTSIZE;
if (len >= sizeof(domain)) len = sizeof(domain) - 1;
domain[0] = 0;
strncat(domain, p->ut_host, len);
}
if (showhost) {
#if CHOP_DOMAIN
/*
* See if this is in our domain.
*/
if (!usedns && (s = strchr(p->ut_host, '.')) != NULL &&
strcmp(s + 1, domainname) == 0) *s = 0;
#endif
if (!altlist) {
snprintf(final, sizeof(final),
fulltime ?
"%-8.8s %-12.12s %-16.16s %-24.24s %-26.26s %-12.12s\n" :
"%-8.8s %-12.12s %-16.16s %-16.16s %-7.7s %-12.12s\n",
p->ut_name, utline,
domain, logintime, logouttime, length);
} else {
snprintf(final, sizeof(final),
fulltime ?
"%-8.8s %-12.12s %-24.24s %-26.26s %-12.12s %s\n" :
"%-8.8s %-12.12s %-16.16s %-7.7s %-12.12s %s\n",
p->ut_name, utline,
logintime, logouttime, length, domain);
}
} else
snprintf(final, sizeof(final),
fulltime ?
"%-8.8s %-12.12s %-24.24s %-26.26s %-12.12s\n" :
"%-8.8s %-12.12s %-16.16s %-7.7s %-12.12s\n",
p->ut_name, utline,
logintime, logouttime, length);
/*
* Print out "final" string safely.
*/
for (s = final; *s; s++) {
if (*s == '\n' || (*s >= 32 && (unsigned char)*s <= 126))
putchar(*s);
else
putchar('*');
}
recsdone++;
if (maxrecs && recsdone >= maxrecs)
return 1;
return 0;
}
/*
* show usage
*/
void usage(char *s)
{
fprintf(stderr, "Usage: %s [-num | -n num] [-f file] "
"[-t YYYYMMDDHHMMSS] "
"[-R] [-adioxF] [username..] [tty..]\n", s);
exit(1);
}
time_t parsetm(char *ts)
{
struct tm u, origu;
time_t tm;
memset(&tm, 0, sizeof(tm));
if (sscanf(ts, "%4d%2d%2d%2d%2d%2d", &u.tm_year,
&u.tm_mon, &u.tm_mday, &u.tm_hour, &u.tm_min,
&u.tm_sec) != 6)
return (time_t)-1;
u.tm_year -= 1900;
u.tm_mon -= 1;
u.tm_isdst = -1;
origu = u;
if ((tm = mktime(&u)) == (time_t)-1)
return tm;
/*
* Unfortunately mktime() is much more forgiving than
* it should be. For example, it'll gladly accept
* "30" as a valid month number. This behavior is by
* design, but we don't like it, so we want to detect
* it and complain.
*/
if (u.tm_year != origu.tm_year ||
u.tm_mon != origu.tm_mon ||
u.tm_mday != origu.tm_mday ||
u.tm_hour != origu.tm_hour ||
u.tm_min != origu.tm_min ||
u.tm_sec != origu.tm_sec)
return (time_t)-1;
return tm;
}
int main(int argc, char **argv)
{
FILE *fp; /* Filepointer of wtmp file */
struct utmp ut; /* Current utmp entry */
struct utmp oldut; /* Old utmp entry to check for duplicates */
struct utmplist *p; /* Pointer into utmplist */
struct utmplist *next;/* Pointer into utmplist */
time_t lastboot = 0; /* Last boottime */
time_t lastrch = 0; /* Last run level change */
time_t lastdown; /* Last downtime */
time_t begintime; /* When wtmp begins */
int whydown = 0; /* Why we went down: crash or shutdown */
int c, x; /* Scratch */
struct stat st; /* To stat the [uw]tmp file */
int quit = 0; /* Flag */
int down = 0; /* Down flag */
int lastb = 0; /* Is this 'lastb' ? */
int extended = 0; /* Lots of info. */
char *altufile = NULL;/* Alternate wtmp */
time_t until = 0; /* at what time to stop parsing the file */
progname = mybasename(argv[0]);
/* Process the arguments. */
while((c = getopt(argc, argv, "f:n:RxadFiot:0123456789")) != EOF)
switch(c) {
case 'R':
showhost = 0;
break;
case 'x':
extended = 1;
break;
case 'n':
maxrecs = atoi(optarg);
break;
case 'o':
oldfmt = 1;
break;
case 'f':
if((altufile = malloc(strlen(optarg)+1)) == NULL) {
fprintf(stderr, "%s: out of memory\n",
progname);
exit(1);
}
strcpy(altufile, optarg);
break;
case 'd':
usedns++;
break;
case 'i':
useip++;
break;
case 'a':
altlist++;
break;
case 'F':
fulltime++;
break;
case 't':
if ((until = parsetm(optarg)) == (time_t)-1) {
fprintf(stderr, "%s: Invalid time value \"%s\"\n",
progname, optarg);
usage(progname);
}
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
maxrecs = 10*maxrecs + c - '0';
break;
default:
usage(progname);
break;
}
if (optind < argc) show = argv + optind;
/*
* Which file do we want to read?
*/
if (strcmp(progname, "lastb") == 0) {
ufile = BTMP_FILE;
lastb = 1;
} else
ufile = WTMP_FILE;
if (altufile)
ufile = altufile;
time(&lastdown);
lastrch = lastdown;
/*
* Fill in 'lastdate'
*/
lastdate = lastdown;
#if CHOP_DOMAIN
/*
* Find out domainname.
*
* This doesn't work on modern systems, where only a DNS
* lookup of the result from hostname() will get you the domainname.
* Remember that domainname() is the NIS domainname, not DNS.
* So basically this whole piece of code is bullshit.
*/
hostname[0] = 0;
(void) gethostname(hostname, sizeof(hostname));
if ((domainname = strchr(hostname, '.')) != NULL) domainname++;
if (domainname == NULL || domainname[0] == 0) {
hostname[0] = 0;
(void) getdomainname(hostname, sizeof(hostname));
hostname[sizeof(hostname) - 1] = 0;
domainname = hostname;
if (strcmp(domainname, "(none)") == 0 || domainname[0] == 0)
domainname = NULL;
}
#endif
/*
* Install signal handlers
*/
signal(SIGINT, int_handler);
signal(SIGQUIT, quit_handler);
/*
* Open the utmp file
*/
if ((fp = fopen(ufile, "r")) == NULL) {
x = errno;
fprintf(stderr, "%s: %s: %s\n", progname, ufile, strerror(errno));
if (altufile == NULL && x == ENOENT)
fprintf(stderr, "Perhaps this file was removed by the "
"operator to prevent logging %s info.\n", progname);
exit(1);
}
/*
* Optimize the buffer size.
*/
setvbuf(fp, NULL, _IOFBF, UCHUNKSIZE);
/*
* Read first structure to capture the time field
*/
if (uread(fp, &ut, NULL) == 1)
begintime = ut.ut_time;
else {
fstat(fileno(fp), &st);
begintime = st.st_ctime;
quit = 1;
}
/*
* Go to end of file minus one structure
* and/or initialize utmp reading code.
*/
uread(fp, NULL, NULL);
/*
* Read struct after struct backwards from the file.
*/
while(!quit) {
if (uread(fp, &ut, &quit) != 1)
break;
if (until && until < ut.ut_time)
continue;
if (memcmp(&ut, &oldut, sizeof(struct utmp)) == 0) continue;
memcpy(&oldut, &ut, sizeof(struct utmp));
lastdate = ut.ut_time;
if (lastb) {
quit = list(&ut, ut.ut_time, R_NORMAL);
continue;
}
/*
* Set ut_type to the correct type.
*/
if (strncmp(ut.ut_line, "~", 1) == 0) {
if (strncmp(ut.ut_user, "shutdown", 8) == 0)
ut.ut_type = SHUTDOWN_TIME;
else if (strncmp(ut.ut_user, "reboot", 6) == 0)
ut.ut_type = BOOT_TIME;
else if (strncmp(ut.ut_user, "runlevel", 8) == 0)
ut.ut_type = RUN_LVL;
}
#if 1 /*def COMPAT*/
/*
* For stupid old applications that don't fill in
* ut_type correctly.
*/
else {
if (ut.ut_type != DEAD_PROCESS &&
ut.ut_name[0] && ut.ut_line[0] &&
strcmp(ut.ut_name, "LOGIN") != 0)
ut.ut_type = USER_PROCESS;
/*
* Even worse, applications that write ghost
* entries: ut_type set to USER_PROCESS but
* empty ut_name...
*/
if (ut.ut_name[0] == 0)
ut.ut_type = DEAD_PROCESS;
/*
* Clock changes.
*/
if (strcmp(ut.ut_name, "date") == 0) {
if (ut.ut_line[0] == '|') ut.ut_type = OLD_TIME;
if (ut.ut_line[0] == '{') ut.ut_type = NEW_TIME;
}
}
#endif
switch (ut.ut_type) {
case SHUTDOWN_TIME:
if (extended) {
strcpy(ut.ut_line, "system down");
quit = list(&ut, lastboot, R_NORMAL);
}
lastdown = lastrch = ut.ut_time;
down = 1;
break;
case OLD_TIME:
case NEW_TIME:
if (extended) {
strcpy(ut.ut_line,
ut.ut_type == NEW_TIME ? "new time" :
"old time");
quit = list(&ut, lastdown, R_TIMECHANGE);
}
break;
case BOOT_TIME:
strcpy(ut.ut_line, "system boot");
quit = list(&ut, lastdown, R_REBOOT);
lastboot = ut.ut_time;
down = 1;
break;
case RUN_LVL:
x = ut.ut_pid & 255;
if (extended) {
sprintf(ut.ut_line, "(to lvl %c)", x);
quit = list(&ut, lastrch, R_NORMAL);
}
if (x == '0' || x == '6') {
lastdown = ut.ut_time;
down = 1;
ut.ut_type = SHUTDOWN_TIME;
}
lastrch = ut.ut_time;
break;
case USER_PROCESS:
/*
* This was a login - show the first matching
* logout record and delete all records with
* the same ut_line.
*/
c = 0;
for (p = utmplist; p; p = next) {
next = p->next;
if (strncmp(p->ut.ut_line, ut.ut_line,
UT_LINESIZE) == 0) {
/* Show it */
if (c == 0) {
quit = list(&ut, p->ut.ut_time,
R_NORMAL);
c = 1;
}
if (p->next) p->next->prev = p->prev;
if (p->prev)
p->prev->next = p->next;
else
utmplist = p->next;
free(p);
}
}
/*
* Not found? Then crashed, down, still
* logged in, or missing logout record.
*/
if (c == 0) {
if (lastboot == 0) {
c = R_NOW;
/* Is process still alive? */
if (ut.ut_pid > 0 &&
kill(ut.ut_pid, 0) != 0 &&
errno == ESRCH)
c = R_PHANTOM;
} else
c = whydown;
quit = list(&ut, lastboot, c);
}
/* FALLTHRU */
case DEAD_PROCESS:
/*
* Just store the data if it is
* interesting enough.
*/
if (ut.ut_line[0] == 0)
break;
if ((p = malloc(sizeof(struct utmplist))) == NULL) {
fprintf(stderr, "%s: out of memory\n",
progname);
exit(1);
}
memcpy(&p->ut, &ut, sizeof(struct utmp));
p->next = utmplist;
p->prev = NULL;
if (utmplist) utmplist->prev = p;
utmplist = p;
break;
}
/*
* If we saw a shutdown/reboot record we can remove
* the entire current utmplist.
*/
if (down) {
lastboot = ut.ut_time;
whydown = (ut.ut_type == SHUTDOWN_TIME) ? R_DOWN : R_CRASH;
for (p = utmplist; p; p = next) {
next = p->next;
free(p);
}
utmplist = NULL;
down = 0;
}
}
printf("\n%s begins %s", mybasename(ufile), ctime(&begintime));
fclose(fp);
/*
* Should we free memory here? Nah. This is not NT :)
*/
return 0;
}