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 | #include <utmp.h>
|
---|
11 |
|
---|
12 | static void touch(const char *filename)
|
---|
13 | {
|
---|
14 | if (access(filename, R_OK | W_OK) == -1)
|
---|
15 | close(open(filename, O_WRONLY | O_CREAT, 0664));
|
---|
16 | }
|
---|
17 |
|
---|
18 | void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
|
---|
19 | {
|
---|
20 | struct utmp utent;
|
---|
21 | char *id;
|
---|
22 | unsigned width;
|
---|
23 |
|
---|
24 | memset(&utent, 0, sizeof(utent));
|
---|
25 | utent.ut_pid = pid;
|
---|
26 | utent.ut_type = new_type;
|
---|
27 | tty_name = skip_dev_pfx(tty_name);
|
---|
28 | safe_strncpy(utent.ut_line, tty_name, sizeof(utent.ut_line));
|
---|
29 | if (username)
|
---|
30 | safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
|
---|
31 | if (hostname)
|
---|
32 | safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
|
---|
33 | utent.ut_tv.tv_sec = time(NULL);
|
---|
34 |
|
---|
35 | /* Invent our own ut_id. ut_id is only 4 chars wide.
|
---|
36 | * Try to fit something remotely meaningful... */
|
---|
37 | id = utent.ut_id;
|
---|
38 | width = sizeof(utent.ut_id);
|
---|
39 | if (tty_name[0] == 'p') {
|
---|
40 | /* if "ptyXXX", map to "pXXX" */
|
---|
41 | /* if "pts/XX", map to "p/XX" */
|
---|
42 | *id++ = 'p';
|
---|
43 | width--;
|
---|
44 | } /* else: usually it's "ttyXXXX", map to "XXXX" */
|
---|
45 | if (strlen(tty_name) > 3)
|
---|
46 | tty_name += 3;
|
---|
47 | strncpy(id, tty_name, width);
|
---|
48 |
|
---|
49 | touch(_PATH_UTMP);
|
---|
50 | //utmpname(_PATH_UTMP);
|
---|
51 | setutent();
|
---|
52 | /* Append new one (hopefully, unless we collide on ut_id) */
|
---|
53 | pututline(&utent);
|
---|
54 | endutent();
|
---|
55 |
|
---|
56 | #if ENABLE_FEATURE_WTMP
|
---|
57 | /* "man utmp" says wtmp file should *not* be created automagically */
|
---|
58 | /*touch(bb_path_wtmp_file);*/
|
---|
59 | updwtmp(bb_path_wtmp_file, &utent);
|
---|
60 | #endif
|
---|
61 | }
|
---|
62 |
|
---|
63 | /*
|
---|
64 | * Read "man utmp" to make sense out of it.
|
---|
65 | */
|
---|
66 | void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
|
---|
67 | {
|
---|
68 | struct utmp utent;
|
---|
69 | struct utmp *utp;
|
---|
70 |
|
---|
71 | touch(_PATH_UTMP);
|
---|
72 | //utmpname(_PATH_UTMP);
|
---|
73 | setutent();
|
---|
74 |
|
---|
75 | /* Did init/getty/telnetd/sshd/... create an entry for us?
|
---|
76 | * It should be (new_type-1), but we'd also reuse
|
---|
77 | * any other potentially stale xxx_PROCESS entry */
|
---|
78 | while ((utp = getutent()) != NULL) {
|
---|
79 | if (utp->ut_pid == pid
|
---|
80 | // && ut->ut_line[0]
|
---|
81 | && utp->ut_id[0] /* must have nonzero id */
|
---|
82 | && ( utp->ut_type == INIT_PROCESS
|
---|
83 | || utp->ut_type == LOGIN_PROCESS
|
---|
84 | || utp->ut_type == USER_PROCESS
|
---|
85 | || utp->ut_type == DEAD_PROCESS
|
---|
86 | )
|
---|
87 | ) {
|
---|
88 | if (utp->ut_type >= new_type) {
|
---|
89 | /* Stale record. Nuke hostname */
|
---|
90 | memset(utp->ut_host, 0, sizeof(utp->ut_host));
|
---|
91 | }
|
---|
92 | /* NB: pututline (see later) searches for matching utent
|
---|
93 | * using getutid(utent) - we must not change ut_id
|
---|
94 | * if we want *exactly this* record to be overwritten!
|
---|
95 | */
|
---|
96 | break;
|
---|
97 | }
|
---|
98 | }
|
---|
99 | //endutent(); - no need, pututline can deal with (and actually likes)
|
---|
100 | //the situation when utmp file is positioned on found record
|
---|
101 |
|
---|
102 | if (!utp) {
|
---|
103 | if (new_type != DEAD_PROCESS)
|
---|
104 | write_new_utmp(pid, new_type, tty_name, username, hostname);
|
---|
105 | else
|
---|
106 | endutent();
|
---|
107 | return;
|
---|
108 | }
|
---|
109 |
|
---|
110 | /* Make a copy. We can't use *utp, pututline's internal getutid
|
---|
111 | * will overwrite it before it is used! */
|
---|
112 | utent = *utp;
|
---|
113 |
|
---|
114 | utent.ut_type = new_type;
|
---|
115 | if (tty_name)
|
---|
116 | safe_strncpy(utent.ut_line, skip_dev_pfx(tty_name), sizeof(utent.ut_line));
|
---|
117 | if (username)
|
---|
118 | safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
|
---|
119 | if (hostname)
|
---|
120 | safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
|
---|
121 | utent.ut_tv.tv_sec = time(NULL);
|
---|
122 |
|
---|
123 | /* Update, or append new one */
|
---|
124 | //setutent();
|
---|
125 | pututline(&utent);
|
---|
126 | endutent();
|
---|
127 |
|
---|
128 | #if ENABLE_FEATURE_WTMP
|
---|
129 | /* "man utmp" says wtmp file should *not* be created automagically */
|
---|
130 | /*touch(bb_path_wtmp_file);*/
|
---|
131 | updwtmp(bb_path_wtmp_file, &utent);
|
---|
132 | #endif
|
---|
133 | }
|
---|