1 /* vi: set sw=4 ts=4: */
3 * utmp/wtmp support routines.
5 * Copyright (C) 2010 Denys Vlasenko
7 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
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);