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/* vi: set sw=4 ts=4: */
/*
* last implementation for busybox
*
* Copyright (C) 2003-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//usage:#define last_trivial_usage
//usage: ""IF_FEATURE_LAST_FANCY("[-HW] [-f FILE]")
//usage:#define last_full_usage "\n\n"
//usage: "Show listing of the last users that logged into the system"
//usage: IF_FEATURE_LAST_FANCY( "\n"
/* //usage: "\n -H Show header line" */
//usage: "\n -W Display with no host column truncation"
//usage: "\n -f FILE Read from FILE instead of /var/log/wtmp"
//usage: )
#include "libbb.h"
/* NB: ut_name and ut_user are the same field, use only one name (ut_user)
* to reduce confusion */
#ifndef SHUTDOWN_TIME
# define SHUTDOWN_TIME 254
#endif
/* Grr... utmp char[] members do not have to be nul-terminated.
* Do what we can while still keeping this reasonably small.
* Note: We are assuming the ut_id[] size is fixed at 4. */
#if defined UT_LINESIZE \
&& ((UT_LINESIZE != 32) || (UT_NAMESIZE != 32) || (UT_HOSTSIZE != 256))
#error struct utmpx member char[] size(s) have changed!
#elif defined __UT_LINESIZE \
&& ((__UT_LINESIZE != 32) || (__UT_NAMESIZE != 32) || (__UT_HOSTSIZE != 256))
/* __UT_NAMESIZE was checked with 64 above, but glibc-2.11 definitely uses 32! */
#error struct utmpx member char[] size(s) have changed!
#endif
#if EMPTY != 0 || RUN_LVL != 1 || BOOT_TIME != 2 || NEW_TIME != 3 || \
OLD_TIME != 4
#error Values for the ut_type field of struct utmpx changed
#endif
int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
{
struct utmpx ut;
int n, file = STDIN_FILENO;
time_t t_tmp;
off_t pos;
static const char _ut_usr[] ALIGN1 =
"runlevel\0" "reboot\0" "shutdown\0";
static const char _ut_lin[] ALIGN1 =
"~\0" "{\0" "|\0" /* "LOGIN\0" "date\0" */;
enum {
TYPE_RUN_LVL = RUN_LVL, /* 1 */
TYPE_BOOT_TIME = BOOT_TIME, /* 2 */
TYPE_SHUTDOWN_TIME = SHUTDOWN_TIME
};
enum {
_TILDE = EMPTY, /* 0 */
TYPE_NEW_TIME, /* NEW_TIME, 3 */
TYPE_OLD_TIME /* OLD_TIME, 4 */
};
if (argv[1]) {
bb_show_usage();
}
file = xopen(bb_path_wtmp_file, O_RDONLY);
printf("%-10s %-14s %-18s %-12.12s %s\n",
"USER", "TTY", "HOST", "LOGIN", "TIME");
/* yikes. We reverse over the file and that is a not too elegant way */
pos = xlseek(file, 0, SEEK_END);
pos = lseek(file, pos - sizeof(ut), SEEK_SET);
while ((n = full_read(file, &ut, sizeof(ut))) > 0) {
if (n != sizeof(ut)) {
bb_perror_msg_and_die("short read");
}
n = index_in_strings(_ut_lin, ut.ut_line);
if (n == _TILDE) { /* '~' */
#if 1
/* do we really need to be cautious here? */
n = index_in_strings(_ut_usr, ut.ut_user);
if (++n > 0)
ut.ut_type = n != 3 ? n : SHUTDOWN_TIME;
#else
if (is_prefixed_with(ut.ut_user, "shutdown"))
ut.ut_type = SHUTDOWN_TIME;
else if (is_prefixed_with(ut.ut_user, "reboot"))
ut.ut_type = BOOT_TIME;
else if (is_prefixed_with(ut.ut_user, "runlevel"))
ut.ut_type = RUN_LVL;
#endif
} else {
if (ut.ut_user[0] == '\0' || strcmp(ut.ut_user, "LOGIN") == 0) {
/* Don't bother. This means we can't find how long
* someone was logged in for. Oh well. */
goto next;
}
if (ut.ut_type != DEAD_PROCESS
&& ut.ut_user[0]
&& ut.ut_line[0]
) {
ut.ut_type = USER_PROCESS;
}
if (strcmp(ut.ut_user, "date") == 0) {
if (n == TYPE_OLD_TIME) { /* '|' */
ut.ut_type = OLD_TIME;
}
if (n == TYPE_NEW_TIME) { /* '{' */
ut.ut_type = NEW_TIME;
}
}
}
if (ut.ut_type != USER_PROCESS) {
switch (ut.ut_type) {
case OLD_TIME:
case NEW_TIME:
case RUN_LVL:
case SHUTDOWN_TIME:
goto next;
case BOOT_TIME:
strcpy(ut.ut_line, "system boot");
}
}
/* manpages say ut_tv.tv_sec *is* time_t,
* but some systems have it wrong */
t_tmp = (time_t)ut.ut_tv.tv_sec;
printf("%-10s %-14s %-18s %-12.12s\n",
ut.ut_user, ut.ut_line, ut.ut_host, ctime(&t_tmp) + 4);
next:
pos -= sizeof(ut);
if (pos <= 0)
break; /* done. */
xlseek(file, pos, SEEK_SET);
}
fflush_stdout_and_exit(EXIT_SUCCESS);
}
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