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util-linux/login-utils/last.c

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/*
* last(1) from sysvinit project, merged into util-linux in Aug 2013.
*
* Copyright (C) 1991-2004 Miquel van Smoorenburg.
* Copyright (C) 2013 Ondrej Oprala <ooprala@redhat.com>
* Karel Zak <kzak@redhat.com>
*
* 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)
*
*
* 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 <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 "c.h"
#include "nls.h"
#include "pathnames.h"
#include "xalloc.h"
#include "closestream.h"
#ifndef SHUTDOWN_TIME
# define SHUTDOWN_TIME 254
#endif
#define CHOP_DOMAIN 0 /* Define to chop off local domainname. */
#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 */
static int maxrecs = 0; /* Maximum number of records to list. */
static int recsdone = 0; /* Number of records listed */
static int showhost = 1; /* Show hostname too? */
static int altlist = 0; /* Show hostname at the end. */
static int usedns = 0; /* Use DNS to lookup the hostname. */
static int useip = 0; /* Print IP address in number format */
static int fulltime = 0; /* Print full dates and times */
static int name_len = 8; /* Default print 8 characters of name */
static int domain_len = 16; /* Default print 16 characters of domain */
static char **show = NULL; /* What do they want us to show */
static char *ufile; /* Filename of this file */
static time_t lastdate; /* Last date we've seen */
#if CHOP_DOMAIn
static char hostname[256]; /* For gethostbyname() */
static char *domainname; /* Our domainname. */
#endif
/*
* Read one utmp entry, return in new format.
* Automatically reposition file pointer.
*/
static 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;
off_t o;
if (quit == NULL && u != NULL) {
/*
* Normal read.
*/
return fread(u, sizeof(struct utmp), 1, fp);
}
if (u == NULL) {
/*
* Initialize and position.
*/
utsize = 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) {
warn(_("seek failed: %s"), ufile);
return 0;
}
bpos = (int)(fpos - o);
if (fread(buf, bpos, 1, fp) != 1) {
warn(_("read failed: %s"), ufile);
return 0;
}
fpos = o;
return 1;
}
/*
* Read one struct. From the buffer if possible.
*/
bpos -= utsize;
if (bpos >= 0) {
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) {
warn(_("seek failed: %s"), ufile);
return 0;
}
/*
* Read another UCHUNKSIZE bytes.
*/
if (fread(buf, UCHUNKSIZE, 1, fp) != 1) {
warn(_("read failed: %s"), ufile);
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;
memcpy(u, tmp, sizeof(struct utmp));
return 1;
}
/*
* Print a short date.
*/
static char *showdate(void)
{
char *s = ctime(&lastdate);
s[16] = 0;
return s;
}
/*
* SIGINT handler
*/
static void int_handler(int sig __attribute__((unused)))
{
errx(EXIT_FAILURE, _("Interrupted %s"), showdate());
}
/*
* SIGQUIT handler
*/
static void quit_handler(int sig __attribute__((unused)))
{
warnx(_("Interrupted %s"), showdate());
signal(SIGQUIT, quit_handler);
}
/*
* Lookup a host with DNS.
*/
static 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;
int mapped = 0;
flags = useip ? NI_NUMERICHOST : 0;
/*
* IPv4 or IPv6 ?
* 1. If last 3 4bytes are 0, must be IPv4
* 2. If IPv6 in IPv4, handle as IPv4
* 3. Anything else is IPv6
*
* Ugly.
*/
if (a[0] == 0 && a[1] == 0 && a[2] == (int32_t)htonl (0xffff))
mapped = 1;
if (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
*/
static 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[512];
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 >= (int)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) {
len = snprintf(final, sizeof(final),
fulltime ?
"%-8.*s %-12.12s %-16.*s %-24.24s %-26.26s %-12.12s\n" :
"%-8.*s %-12.12s %-16.*s %-16.16s %-7.7s %-12.12s\n",
name_len, p->ut_name, utline,
domain_len, domain, logintime, logouttime, length);
} else {
len = snprintf(final, sizeof(final),
fulltime ?
"%-8.*s %-12.12s %-24.24s %-26.26s %-12.12s %s\n" :
"%-8.*s %-12.12s %-16.16s %-7.7s %-12.12s %s\n",
name_len, p->ut_name, utline,
logintime, logouttime, length, domain);
}
} else
len = snprintf(final, sizeof(final),
fulltime ?
"%-8.*s %-12.12s %-24.24s %-26.26s %-12.12s\n" :
"%-8.*s %-12.12s %-16.16s %-7.7s %-12.12s\n",
name_len, p->ut_name, utline,
logintime, logouttime, length);
#if defined(__GLIBC__)
# if (__GLIBC__ == 2) && (__GLIBC_MINOR__ == 0)
final[sizeof(final)-1] = '\0';
# endif
#endif
/*
* Print out "final" string safely.
*/
for (s = final; *s; s++) {
if (*s == '\n' || (*s >= 32 && (unsigned char)*s <= 126))
putchar(*s);
else
putchar('*');
}
if (len < 0 || (size_t)len >= sizeof(final))
putchar('\n');
recsdone++;
if (maxrecs && recsdone >= maxrecs)
return 1;
return 0;
}
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fputs(USAGE_HEADER, out);
fprintf(out, _(
" %s [options]\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -<number> how many lines to show\n"), out);
fputs(_(" -a, --hostlast display hostnames in the last column\n"), out);
fputs(_(" -d, --dns translate the IP number back into a hostname\n"), out);
fprintf(out,
_(" -f, --file <file> use a specific file instead of %s\n"), _PATH_WTMP);
fputs(_(" -F, --fulltimes print full login and logout times and dates\n"), out);
fputs(_(" -i, --ip display IP numbers in numbers-and-dots notation\n"), out);
fputs(_(" -n, --limit <number> how many lines to show\n"), out);
fputs(_(" -R, --nohostname don't display the hostname field\n"), out);
fputs(_(" -t, --until <YYYYMMDDHHMMSS> display the state of the specified time\n"), out);
fputs(_(" -w, --fullnames display full user and domain names\n"), out);
fputs(_(" -x, --system display system shutdown entries and run level changes\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("last(1))"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static 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 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 */
static const struct option long_opts[] = {
{ "limit", required_argument, NULL, 'n' },
{ "help", no_argument, NULL, 'h' },
{ "file", required_argument, NULL, 'f' },
{ "nohostname", no_argument, NULL, 'R' },
{ "version", no_argument, NULL, 'V' },
{ "hostlast", no_argument, NULL, 'a' },
{ "until", required_argument, NULL, 't' },
{ "system", no_argument, NULL, 'x' },
{ "dns", no_argument, NULL, 'd' },
{ "ip", no_argument, NULL, 'i' },
{ "fulltimes", no_argument, NULL, 'F' },
{ "fullnames", no_argument, NULL, 'w' },
{ NULL, 0, NULL, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv,
"hVf:n:RxadFit:0123456789w", long_opts, NULL)) != -1) {
switch(c) {
case 'h':
usage(stdout);
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'R':
showhost = 0;
break;
case 'x':
extended = 1;
break;
case 'n':
maxrecs = atoi(optarg);
break;
case 'f':
altufile = xstrdup(optarg);
break;
case 'd':
usedns++;
break;
case 'i':
useip++;
break;
case 'a':
altlist++;
break;
case 'F':
fulltime++;
break;
case 't':
until = parsetm(optarg);
if (until == (time_t) -1)
errx(EXIT_FAILURE, _("invalid time value \"%s\""), optarg);
break;
case 'w':
if (UT_NAMESIZE > name_len)
name_len = UT_NAMESIZE;
if (UT_HOSTSIZE > domain_len)
domain_len = UT_HOSTSIZE;
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(stderr);
break;
}
}
if (optind < argc)
show = argv + optind;
/*
* Which file do we want to read?
*/
lastb = !strcmp(program_invocation_short_name, "lastb");
ufile = altufile ? altufile : lastb ? _PATH_BTMP : _PATH_WTMP;
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;
gethostname(hostname, sizeof(hostname));
if ((domainname = strchr(hostname, '.')) != NULL)
domainname++;
if (domainname == NULL || domainname[0] == 0) {
hostname[0] = 0;
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)
err(EXIT_FAILURE, _("cannot open %s"), ufile);
/*
* 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;
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;
p = xmalloc(sizeof(struct utmplist));
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"), basename(ufile), ctime(&begintime));
fclose(fp);
return EXIT_SUCCESS;
}
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