/* 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 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 #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 (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 (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; #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); }