blob: 24f6e1c7820ed49b8280a4b01826162cff275654
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * last implementation for busybox |
4 | * |
5 | * Copyright (C) 2003-2004 by Erik Andersen <andersen@codepoet.org> |
6 | * |
7 | * Licensed under GPLv2, see file LICENSE in this source tree. |
8 | */ |
9 | |
10 | //usage:#define last_trivial_usage |
11 | //usage: ""IF_FEATURE_LAST_FANCY("[-HW] [-f FILE]") |
12 | //usage:#define last_full_usage "\n\n" |
13 | //usage: "Show listing of the last users that logged into the system" |
14 | //usage: IF_FEATURE_LAST_FANCY( "\n" |
15 | /* //usage: "\n -H Show header line" */ |
16 | //usage: "\n -W Display with no host column truncation" |
17 | //usage: "\n -f FILE Read from FILE instead of /var/log/wtmp" |
18 | //usage: ) |
19 | |
20 | #include "libbb.h" |
21 | |
22 | /* NB: ut_name and ut_user are the same field, use only one name (ut_user) |
23 | * to reduce confusion */ |
24 | |
25 | #ifndef SHUTDOWN_TIME |
26 | # define SHUTDOWN_TIME 254 |
27 | #endif |
28 | |
29 | /* Grr... utmp char[] members do not have to be nul-terminated. |
30 | * Do what we can while still keeping this reasonably small. |
31 | * Note: We are assuming the ut_id[] size is fixed at 4. */ |
32 | |
33 | #if defined UT_LINESIZE \ |
34 | && ((UT_LINESIZE != 32) || (UT_NAMESIZE != 32) || (UT_HOSTSIZE != 256)) |
35 | #error struct utmp member char[] size(s) have changed! |
36 | #elif defined __UT_LINESIZE \ |
37 | && ((__UT_LINESIZE != 32) || (__UT_NAMESIZE != 64) || (__UT_HOSTSIZE != 256)) |
38 | #error struct utmp member char[] size(s) have changed! |
39 | #endif |
40 | |
41 | #if EMPTY != 0 || RUN_LVL != 1 || BOOT_TIME != 2 || NEW_TIME != 3 || \ |
42 | OLD_TIME != 4 |
43 | #error Values for the ut_type field of struct utmp changed |
44 | #endif |
45 | |
46 | int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
47 | int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM) |
48 | { |
49 | struct utmp ut; |
50 | int n, file = STDIN_FILENO; |
51 | time_t t_tmp; |
52 | off_t pos; |
53 | static const char _ut_usr[] ALIGN1 = |
54 | "runlevel\0" "reboot\0" "shutdown\0"; |
55 | static const char _ut_lin[] ALIGN1 = |
56 | "~\0" "{\0" "|\0" /* "LOGIN\0" "date\0" */; |
57 | enum { |
58 | TYPE_RUN_LVL = RUN_LVL, /* 1 */ |
59 | TYPE_BOOT_TIME = BOOT_TIME, /* 2 */ |
60 | TYPE_SHUTDOWN_TIME = SHUTDOWN_TIME |
61 | }; |
62 | enum { |
63 | _TILDE = EMPTY, /* 0 */ |
64 | TYPE_NEW_TIME, /* NEW_TIME, 3 */ |
65 | TYPE_OLD_TIME /* OLD_TIME, 4 */ |
66 | }; |
67 | |
68 | if (argv[1]) { |
69 | bb_show_usage(); |
70 | } |
71 | file = xopen(bb_path_wtmp_file, O_RDONLY); |
72 | |
73 | printf("%-10s %-14s %-18s %-12.12s %s\n", |
74 | "USER", "TTY", "HOST", "LOGIN", "TIME"); |
75 | /* yikes. We reverse over the file and that is a not too elegant way */ |
76 | pos = xlseek(file, 0, SEEK_END); |
77 | pos = lseek(file, pos - sizeof(ut), SEEK_SET); |
78 | while ((n = full_read(file, &ut, sizeof(ut))) > 0) { |
79 | if (n != sizeof(ut)) { |
80 | bb_perror_msg_and_die("short read"); |
81 | } |
82 | n = index_in_strings(_ut_lin, ut.ut_line); |
83 | if (n == _TILDE) { /* '~' */ |
84 | #if 1 |
85 | /* do we really need to be cautious here? */ |
86 | n = index_in_strings(_ut_usr, ut.ut_user); |
87 | if (++n > 0) |
88 | ut.ut_type = n != 3 ? n : SHUTDOWN_TIME; |
89 | #else |
90 | if (strncmp(ut.ut_user, "shutdown", 8) == 0) |
91 | ut.ut_type = SHUTDOWN_TIME; |
92 | else if (strncmp(ut.ut_user, "reboot", 6) == 0) |
93 | ut.ut_type = BOOT_TIME; |
94 | else if (strncmp(ut.ut_user, "runlevel", 8) == 0) |
95 | ut.ut_type = RUN_LVL; |
96 | #endif |
97 | } else { |
98 | if (ut.ut_user[0] == '\0' || strcmp(ut.ut_user, "LOGIN") == 0) { |
99 | /* Don't bother. This means we can't find how long |
100 | * someone was logged in for. Oh well. */ |
101 | goto next; |
102 | } |
103 | if (ut.ut_type != DEAD_PROCESS |
104 | && ut.ut_user[0] |
105 | && ut.ut_line[0] |
106 | ) { |
107 | ut.ut_type = USER_PROCESS; |
108 | } |
109 | if (strcmp(ut.ut_user, "date") == 0) { |
110 | if (n == TYPE_OLD_TIME) { /* '|' */ |
111 | ut.ut_type = OLD_TIME; |
112 | } |
113 | if (n == TYPE_NEW_TIME) { /* '{' */ |
114 | ut.ut_type = NEW_TIME; |
115 | } |
116 | } |
117 | } |
118 | |
119 | if (ut.ut_type != USER_PROCESS) { |
120 | switch (ut.ut_type) { |
121 | case OLD_TIME: |
122 | case NEW_TIME: |
123 | case RUN_LVL: |
124 | case SHUTDOWN_TIME: |
125 | goto next; |
126 | case BOOT_TIME: |
127 | strcpy(ut.ut_line, "system boot"); |
128 | } |
129 | } |
130 | /* manpages say ut_tv.tv_sec *is* time_t, |
131 | * but some systems have it wrong */ |
132 | t_tmp = (time_t)ut.ut_tv.tv_sec; |
133 | printf("%-10s %-14s %-18s %-12.12s\n", |
134 | ut.ut_user, ut.ut_line, ut.ut_host, ctime(&t_tmp) + 4); |
135 | next: |
136 | pos -= sizeof(ut); |
137 | if (pos <= 0) |
138 | break; /* done. */ |
139 | xlseek(file, pos, SEEK_SET); |
140 | } |
141 | |
142 | fflush_stdout_and_exit(EXIT_SUCCESS); |
143 | } |
144 |