source: branches/3.2/mindi-busybox/libbb/utmp.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
  • Property svn:eol-style set to native
File size: 3.6 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * utmp/wtmp support routines.
4 *
5 * Copyright (C) 2010 Denys Vlasenko
6 *
7 * Licensed under GPLv2, see file LICENSE in this source tree.
8 */
9#include "libbb.h"
10
11static void touch(const char *filename)
12{
13    if (access(filename, R_OK | W_OK) == -1)
14        close(open(filename, O_WRONLY | O_CREAT, 0664));
15}
16
17void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
18{
19    struct utmp utent;
20    char *id;
21    unsigned width;
22
23    memset(&utent, 0, sizeof(utent));
24    utent.ut_pid = pid;
25    utent.ut_type = new_type;
26    tty_name = skip_dev_pfx(tty_name);
27    safe_strncpy(utent.ut_line, tty_name, sizeof(utent.ut_line));
28    if (username)
29        safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
30    if (hostname)
31        safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
32    utent.ut_tv.tv_sec = time(NULL);
33
34    /* Invent our own ut_id. ut_id is only 4 chars wide.
35     * Try to fit something remotely meaningful... */
36    id = utent.ut_id;
37    width = sizeof(utent.ut_id);
38    if (tty_name[0] == 'p') {
39        /* if "ptyXXX", map to "pXXX" */
40        /* if "pts/XX", map to "p/XX" */
41        *id++ = 'p';
42        width--;
43    } /* else: usually it's "ttyXXXX", map to "XXXX" */
44    if (strlen(tty_name) > 3)
45        tty_name += 3;
46    strncpy(id, tty_name, width);
47
48    touch(_PATH_UTMP);
49    //utmpname(_PATH_UTMP);
50    setutent();
51    /* Append new one (hopefully, unless we collide on ut_id) */
52    pututline(&utent);
53    endutent();
54
55#if ENABLE_FEATURE_WTMP
56    /* "man utmp" says wtmp file should *not* be created automagically */
57    /*touch(bb_path_wtmp_file);*/
58    updwtmp(bb_path_wtmp_file, &utent);
59#endif
60}
61
62/*
63 * Read "man utmp" to make sense out of it.
64 */
65void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
66{
67    struct utmp utent;
68    struct utmp *utp;
69
70    touch(_PATH_UTMP);
71    //utmpname(_PATH_UTMP);
72    setutent();
73
74    /* Did init/getty/telnetd/sshd/... create an entry for us?
75     * It should be (new_type-1), but we'd also reuse
76     * any other potentially stale xxx_PROCESS entry */
77    while ((utp = getutent()) != NULL) {
78        if (utp->ut_pid == pid
79        // && ut->ut_line[0]
80         && utp->ut_id[0] /* must have nonzero id */
81         && (  utp->ut_type == INIT_PROCESS
82            || utp->ut_type == LOGIN_PROCESS
83            || utp->ut_type == USER_PROCESS
84            || utp->ut_type == DEAD_PROCESS
85            )
86        ) {
87            if (utp->ut_type >= new_type) {
88                /* Stale record. Nuke hostname */
89                memset(utp->ut_host, 0, sizeof(utp->ut_host));
90            }
91            /* NB: pututline (see later) searches for matching utent
92             * using getutid(utent) - we must not change ut_id
93             * if we want *exactly this* record to be overwritten!
94             */
95            break;
96        }
97    }
98    //endutent(); - no need, pututline can deal with (and actually likes)
99    //the situation when utmp file is positioned on found record
100
101    if (!utp) {
102        if (new_type != DEAD_PROCESS)
103            write_new_utmp(pid, new_type, tty_name, username, hostname);
104        else
105            endutent();
106        return;
107    }
108
109    /* Make a copy. We can't use *utp, pututline's internal getutid
110     * will overwrite it before it is used! */
111    utent = *utp;
112
113    utent.ut_type = new_type;
114    if (tty_name)
115        safe_strncpy(utent.ut_line, skip_dev_pfx(tty_name), sizeof(utent.ut_line));
116    if (username)
117        safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
118    if (hostname)
119        safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
120    utent.ut_tv.tv_sec = time(NULL);
121
122    /* Update, or append new one */
123    //setutent();
124    pututline(&utent);
125    endutent();
126
127#if ENABLE_FEATURE_WTMP
128    /* "man utmp" says wtmp file should *not* be created automagically */
129    /*touch(bb_path_wtmp_file);*/
130    updwtmp(bb_path_wtmp_file, &utent);
131#endif
132}
Note: See TracBrowser for help on using the repository browser.