*
* Copyright (C) 2003-2004 by Erik Andersen <andersen@codepoet.org>
*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
-#include <sys/types.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <utmp.h>
-#include <sys/stat.h>
-#include <errno.h>
-#include <string.h>
-#include <time.h>
-#include "busybox.h"
+//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.
+/* 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
+
+#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)
+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;
}
}
+ /* 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);
+ 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);
}
projects / platform / upstream / busybox.git / blobdiff