135 lines
3.6 KiB
C
135 lines
3.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* last implementation for busybox
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*
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* Copyright (C) 2003-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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#include <utmp.h>
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/* NB: ut_name and ut_user are the same field, use only one name (ut_user)
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* to reduce confusion */
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#ifndef SHUTDOWN_TIME
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# define SHUTDOWN_TIME 254
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#endif
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/* Grr... utmp char[] members do not have to be nul-terminated.
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* Do what we can while still keeping this reasonably small.
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* Note: We are assuming the ut_id[] size is fixed at 4. */
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#if defined UT_LINESIZE \
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&& ((UT_LINESIZE != 32) || (UT_NAMESIZE != 32) || (UT_HOSTSIZE != 256))
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#error struct utmp member char[] size(s) have changed!
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#elif defined __UT_LINESIZE \
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&& ((__UT_LINESIZE != 32) || (__UT_NAMESIZE != 64) || (__UT_HOSTSIZE != 256))
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#error struct utmp member char[] size(s) have changed!
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#endif
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#if EMPTY != 0 || RUN_LVL != 1 || BOOT_TIME != 2 || NEW_TIME != 3 || \
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OLD_TIME != 4
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#error Values for the ut_type field of struct utmp changed
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#endif
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int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
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{
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struct utmp ut;
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int n, file = STDIN_FILENO;
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time_t t_tmp;
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off_t pos;
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static const char _ut_usr[] ALIGN1 =
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"runlevel\0" "reboot\0" "shutdown\0";
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static const char _ut_lin[] ALIGN1 =
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"~\0" "{\0" "|\0" /* "LOGIN\0" "date\0" */;
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enum {
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TYPE_RUN_LVL = RUN_LVL, /* 1 */
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TYPE_BOOT_TIME = BOOT_TIME, /* 2 */
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TYPE_SHUTDOWN_TIME = SHUTDOWN_TIME
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};
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enum {
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_TILDE = EMPTY, /* 0 */
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TYPE_NEW_TIME, /* NEW_TIME, 3 */
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TYPE_OLD_TIME /* OLD_TIME, 4 */
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};
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if (argv[1]) {
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bb_show_usage();
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}
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file = xopen(bb_path_wtmp_file, O_RDONLY);
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printf("%-10s %-14s %-18s %-12.12s %s\n",
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"USER", "TTY", "HOST", "LOGIN", "TIME");
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/* yikes. We reverse over the file and that is a not too elegant way */
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pos = xlseek(file, 0, SEEK_END);
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pos = lseek(file, pos - sizeof(ut), SEEK_SET);
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while ((n = full_read(file, &ut, sizeof(ut))) > 0) {
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if (n != sizeof(ut)) {
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bb_perror_msg_and_die("short read");
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}
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n = index_in_strings(_ut_lin, ut.ut_line);
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if (n == _TILDE) { /* '~' */
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#if 1
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/* do we really need to be cautious here? */
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n = index_in_strings(_ut_usr, ut.ut_user);
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if (++n > 0)
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ut.ut_type = n != 3 ? n : SHUTDOWN_TIME;
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#else
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if (strncmp(ut.ut_user, "shutdown", 8) == 0)
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ut.ut_type = SHUTDOWN_TIME;
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else if (strncmp(ut.ut_user, "reboot", 6) == 0)
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ut.ut_type = BOOT_TIME;
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else if (strncmp(ut.ut_user, "runlevel", 8) == 0)
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ut.ut_type = RUN_LVL;
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#endif
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} else {
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if (ut.ut_user[0] == '\0' || strcmp(ut.ut_user, "LOGIN") == 0) {
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/* Don't bother. This means we can't find how long
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* someone was logged in for. Oh well. */
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goto next;
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}
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if (ut.ut_type != DEAD_PROCESS
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&& ut.ut_user[0]
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&& ut.ut_line[0]
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) {
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ut.ut_type = USER_PROCESS;
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}
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if (strcmp(ut.ut_user, "date") == 0) {
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if (n == TYPE_OLD_TIME) { /* '|' */
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ut.ut_type = OLD_TIME;
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}
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if (n == TYPE_NEW_TIME) { /* '{' */
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ut.ut_type = NEW_TIME;
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}
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}
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}
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if (ut.ut_type != USER_PROCESS) {
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switch (ut.ut_type) {
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case OLD_TIME:
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case NEW_TIME:
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case RUN_LVL:
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case SHUTDOWN_TIME:
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goto next;
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case BOOT_TIME:
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strcpy(ut.ut_line, "system boot");
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}
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}
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/* manpages say ut_tv.tv_sec *is* time_t,
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* but some systems have it wrong */
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t_tmp = (time_t)ut.ut_tv.tv_sec;
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printf("%-10s %-14s %-18s %-12.12s\n",
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ut.ut_user, ut.ut_line, ut.ut_host, ctime(&t_tmp) + 4);
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next:
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pos -= sizeof(ut);
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if (pos <= 0)
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break; /* done. */
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xlseek(file, pos, SEEK_SET);
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}
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fflush_stdout_and_exit(EXIT_SUCCESS);
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}
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