134 lines
3.6 KiB
C
134 lines
3.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* utmp/wtmp support routines.
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*
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* Copyright (C) 2010 Denys Vlasenko
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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#include <utmp.h>
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static void touch(const char *filename)
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{
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if (access(filename, R_OK | W_OK) == -1)
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close(open(filename, O_WRONLY | O_CREAT, 0664));
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}
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void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
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{
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struct utmp utent;
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char *id;
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unsigned width;
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memset(&utent, 0, sizeof(utent));
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utent.ut_pid = pid;
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utent.ut_type = new_type;
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tty_name = skip_dev_pfx(tty_name);
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safe_strncpy(utent.ut_line, tty_name, sizeof(utent.ut_line));
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if (username)
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safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
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if (hostname)
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safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
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utent.ut_tv.tv_sec = time(NULL);
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/* Invent our own ut_id. ut_id is only 4 chars wide.
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* Try to fit something remotely meaningful... */
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id = utent.ut_id;
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width = sizeof(utent.ut_id);
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if (tty_name[0] == 'p') {
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/* if "ptyXXX", map to "pXXX" */
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/* if "pts/XX", map to "p/XX" */
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*id++ = 'p';
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width--;
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} /* else: usually it's "ttyXXXX", map to "XXXX" */
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if (strlen(tty_name) > 3)
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tty_name += 3;
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strncpy(id, tty_name, width);
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touch(_PATH_UTMP);
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//utmpname(_PATH_UTMP);
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setutent();
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/* Append new one (hopefully, unless we collide on ut_id) */
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pututline(&utent);
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endutent();
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#if ENABLE_FEATURE_WTMP
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/* "man utmp" says wtmp file should *not* be created automagically */
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/*touch(bb_path_wtmp_file);*/
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updwtmp(bb_path_wtmp_file, &utent);
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#endif
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}
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/*
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* Read "man utmp" to make sense out of it.
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*/
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void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
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{
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struct utmp utent;
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struct utmp *utp;
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touch(_PATH_UTMP);
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//utmpname(_PATH_UTMP);
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setutent();
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/* Did init/getty/telnetd/sshd/... create an entry for us?
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* It should be (new_type-1), but we'd also reuse
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* any other potentially stale xxx_PROCESS entry */
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while ((utp = getutent()) != NULL) {
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if (utp->ut_pid == pid
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// && ut->ut_line[0]
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&& utp->ut_id[0] /* must have nonzero id */
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&& ( utp->ut_type == INIT_PROCESS
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|| utp->ut_type == LOGIN_PROCESS
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|| utp->ut_type == USER_PROCESS
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|| utp->ut_type == DEAD_PROCESS
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)
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) {
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if (utp->ut_type >= new_type) {
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/* Stale record. Nuke hostname */
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memset(utp->ut_host, 0, sizeof(utp->ut_host));
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}
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/* NB: pututline (see later) searches for matching utent
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* using getutid(utent) - we must not change ut_id
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* if we want *exactly this* record to be overwritten!
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*/
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break;
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}
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}
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//endutent(); - no need, pututline can deal with (and actually likes)
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//the situation when utmp file is positioned on found record
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if (!utp) {
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if (new_type != DEAD_PROCESS)
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write_new_utmp(pid, new_type, tty_name, username, hostname);
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else
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endutent();
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return;
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}
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/* Make a copy. We can't use *utp, pututline's internal getutid
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* will overwrite it before it is used! */
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utent = *utp;
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utent.ut_type = new_type;
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if (tty_name)
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safe_strncpy(utent.ut_line, skip_dev_pfx(tty_name), sizeof(utent.ut_line));
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if (username)
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safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
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if (hostname)
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safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
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utent.ut_tv.tv_sec = time(NULL);
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/* Update, or append new one */
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//setutent();
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pututline(&utent);
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endutent();
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#if ENABLE_FEATURE_WTMP
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/* "man utmp" says wtmp file should *not* be created automagically */
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/*touch(bb_path_wtmp_file);*/
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updwtmp(bb_path_wtmp_file, &utent);
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#endif
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}
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