1 /* vi: set sw=4 ts=4: */
3 * utmp/wtmp support routines.
5 * Copyright (C) 2010 Denys Vlasenko
7 * Licensed under GPLv2, see file LICENSE in this source tree.
12 static void touch(const char *filename
)
14 if (access(filename
, R_OK
| W_OK
) == -1)
15 close(open(filename
, O_WRONLY
| O_CREAT
, 0664));
18 void FAST_FUNC
write_new_utmp(pid_t pid
, int new_type
, const char *tty_name
, const char *username
, const char *hostname
)
24 memset(&utent
, 0, sizeof(utent
));
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
));
30 safe_strncpy(utent
.ut_user
, username
, sizeof(utent
.ut_user
));
32 safe_strncpy(utent
.ut_host
, hostname
, sizeof(utent
.ut_host
));
33 utent
.ut_tv
.tv_sec
= time(NULL
);
35 /* Invent our own ut_id. ut_id is only 4 chars wide.
36 * Try to fit something remotely meaningful... */
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" */
44 } /* else: usually it's "ttyXXXX", map to "XXXX" */
45 if (strlen(tty_name
) > 3)
47 strncpy(id
, tty_name
, width
);
50 //utmpname(_PATH_UTMP);
52 /* Append new one (hopefully, unless we collide on ut_id) */
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
);
64 * Read "man utmp" to make sense out of it.
66 void FAST_FUNC
update_utmp(pid_t pid
, int new_type
, const char *tty_name
, const char *username
, const char *hostname
)
72 //utmpname(_PATH_UTMP);
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
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
88 if (utp
->ut_type
>= new_type
) {
89 /* Stale record. Nuke hostname */
90 memset(utp
->ut_host
, 0, sizeof(utp
->ut_host
));
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!
99 //endutent(); - no need, pututline can deal with (and actually likes)
100 //the situation when utmp file is positioned on found record
103 if (new_type
!= DEAD_PROCESS
)
104 write_new_utmp(pid
, new_type
, tty_name
, username
, hostname
);
110 /* Make a copy. We can't use *utp, pututline's internal getutid
111 * will overwrite it before it is used! */
114 utent
.ut_type
= new_type
;
116 safe_strncpy(utent
.ut_line
, skip_dev_pfx(tty_name
), sizeof(utent
.ut_line
));
118 safe_strncpy(utent
.ut_user
, username
, sizeof(utent
.ut_user
));
120 safe_strncpy(utent
.ut_host
, hostname
, sizeof(utent
.ut_host
));
121 utent
.ut_tv
.tv_sec
= time(NULL
);
123 /* Update, or append new one */
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
);