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.
11 static void touch(const char *filename)
13 if (access(filename, R_OK | W_OK) == -1)
14 close(open(filename, O_WRONLY | O_CREAT, 0664));
17 void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
23 memset(&utent, 0, sizeof(utent));
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));
29 safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
31 safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
32 utent.ut_tv.tv_sec = time(NULL);
34 /* Invent our own ut_id. ut_id is only 4 chars wide.
35 * Try to fit something remotely meaningful... */
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" */
43 } /* else: usually it's "ttyXXXX", map to "XXXX" */
44 if (strlen(tty_name) > 3)
46 strncpy(id, tty_name, width);
49 //utmpname(_PATH_UTMP);
51 /* Append new one (hopefully, unless we collide on ut_id) */
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);
63 * Read "man utmp" to make sense out of it.
65 void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
71 //utmpname(_PATH_UTMP);
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
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
87 if (utp->ut_type >= new_type) {
88 /* Stale record. Nuke hostname */
89 memset(utp->ut_host, 0, sizeof(utp->ut_host));
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!
98 //endutent(); - no need, pututline can deal with (and actually likes)
99 //the situation when utmp file is positioned on found record
102 if (new_type != DEAD_PROCESS)
103 write_new_utmp(pid, new_type, tty_name, username, hostname);
109 /* Make a copy. We can't use *utp, pututline's internal getutid
110 * will overwrite it before it is used! */
113 utent.ut_type = new_type;
115 safe_strncpy(utent.ut_line, skip_dev_pfx(tty_name), sizeof(utent.ut_line));
117 safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
119 safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
120 utent.ut_tv.tv_sec = time(NULL);
122 /* Update, or append new one */
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);