diff options
Diffstat (limited to 'util-linux/last.c')
| -rw-r--r-- | util-linux/last.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/util-linux/last.c b/util-linux/last.c new file mode 100644 index 0000000..b3f125c --- /dev/null +++ b/util-linux/last.c @@ -0,0 +1,166 @@ +/* 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. + */ +//config:config LAST +//config: bool "last" +//config: default y +//config: depends on FEATURE_WTMP +//config: help +//config: 'last' displays a list of the last users that logged into the system. +//config: +//config:config FEATURE_LAST_FANCY +//config: bool "Output extra information" +//config: default y +//config: depends on LAST +//config: help +//config: 'last' displays detailed information about the last users that +//config: logged into the system (mimics sysvinit last). +900 bytes. + +//applet:IF_LAST(APPLET(last, BB_DIR_USR_BIN, BB_SUID_DROP)) + +//kbuild:ifeq ($(CONFIG_FEATURE_LAST_FANCY),y) +//kbuild:lib-$(CONFIG_FEATURE_LAST_FANCY) += last_fancy.o +//kbuild:else +//kbuild:lib-$(CONFIG_LAST) += last.o +//kbuild:endif + +//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); +} |