1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/* 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 (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);
}
|
