X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=miscutils%2Flast.c;h=888a0a3d120df8e9a3ad3a597cc456d1515a7f1c;hb=2c3b71a0d2e6e94d8fb75c6879b1b8203cea9e5a;hp=86613bf27a88b32f032e9b9ebd96f7a17c9511e1;hpb=c7bda1ce659294d6e22c06e087f6f265983c7578;p=oweals%2Fbusybox.git diff --git a/miscutils/last.c b/miscutils/last.c index 86613bf27..888a0a3d1 100644 --- a/miscutils/last.c +++ b/miscutils/last.c @@ -4,104 +4,131 @@ * * Copyright (C) 2003-2004 by Erik Andersen * - * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * + * Licensed under GPLv2, see file LICENSE in this source tree. */ -#include -#include -#include -#include +#include "libbb.h" #include -#include -#include -#include -#include -#include "busybox.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. +/* 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 (UT_LINESIZE != 32) || (UT_NAMESIZE != 32) || (UT_HOSTSIZE != 256) +#if defined UT_LINESIZE \ + && ((UT_LINESIZE != 32) || (UT_NAMESIZE != 32) || (UT_HOSTSIZE != 256)) +#error struct utmp member char[] size(s) have changed! +#elif defined __UT_LINESIZE \ + && ((__UT_LINESIZE != 32) || (__UT_NAMESIZE != 64) || (__UT_HOSTSIZE != 256)) #error struct utmp member char[] size(s) have changed! #endif -extern int last_main(int argc, char **argv) +#if EMPTY != 0 || RUN_LVL != 1 || BOOT_TIME != 2 || NEW_TIME != 3 || \ + OLD_TIME != 4 +#error Values for the ut_type field of struct utmp changed +#endif + +int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM) { struct utmp 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 (argc > 1) { + if (argv[1]) { bb_show_usage(); } - file = bb_xopen(_PATH_WTMP, O_RDONLY); - - printf("%-10s %-14s %-18s %-12.12s %s\n", "USER", "TTY", "HOST", "LOGIN", "TIME"); - while ((n = safe_read(file, (void*)&ut, sizeof(struct utmp))) != 0) { + file = xopen(bb_path_wtmp_file, O_RDONLY); - if (n != sizeof(struct utmp)) { + 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"); } - - if (strncmp(ut.ut_line, "~", 1) == 0) { + 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 (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", 7) == 0) + else if (strncmp(ut.ut_user, "runlevel", 8) == 0) ut.ut_type = RUN_LVL; +#endif } else { - if (!ut.ut_name[0] || strcmp(ut.ut_name, "LOGIN") == 0 || - ut.ut_name[0] == 0) - { + 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. */ - continue; + goto next; } - if (ut.ut_type != DEAD_PROCESS && - ut.ut_name[0] && ut.ut_line[0]) - { + if (ut.ut_type != DEAD_PROCESS + && ut.ut_user[0] + && ut.ut_line[0] + ) { ut.ut_type = USER_PROCESS; } - 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; + 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) { + if (ut.ut_type != USER_PROCESS) { switch (ut.ut_type) { case OLD_TIME: case NEW_TIME: case RUN_LVL: case SHUTDOWN_TIME: - continue; + goto next; case BOOT_TIME: strcpy(ut.ut_line, "system boot"); - break; } } - - printf("%-10s %-14s %-18s %-12.12s\n", ut.ut_user, ut.ut_line, ut.ut_host, - ctime(&(ut.ut_tv.tv_sec)) + 4); + /* 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); } - bb_fflush_stdout_and_exit(EXIT_SUCCESS); + fflush_stdout_and_exit(EXIT_SUCCESS); }