source: branches/3.2/mindi-busybox/miscutils/last.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 4.0 KB
Line 
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
46int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
47int 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}
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