ulog_login_pseudo.c revision 331722 
1/*-
2 * Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/lib/libulog/ulog_login_pseudo.c 331722 2018-03-29 02:50:57Z eadler $");
29
30#include <sys/wait.h>
31
32#include <errno.h>
33#include <signal.h>
34#include <stdlib.h>
35#include <sysexits.h>
36#include <unistd.h>
37#include "ulog.h"
38
39#define	_PATH_ULOG_HELPER	"/usr/libexec/ulog-helper"
40
41/*
42 * Registering login sessions.
43 */
44
45static void
46ulog_exec_helper(int fd, char const * const argv[])
47{
48	sigset_t oblock, nblock;
49	pid_t pid, wpid;
50	int status;
51
52	/* Block SIGCHLD. */
53	sigemptyset(&nblock);
54	sigaddset(&nblock, SIGCHLD);
55	sigprocmask(SIG_BLOCK, &nblock, &oblock);
56
57	switch (pid = fork()) {
58	case -1:
59		break;
60	case 0:
61		/* Execute helper program. */
62		if (dup2(fd, STDIN_FILENO) == -1)
63			exit(EX_UNAVAILABLE);
64		sigprocmask(SIG_SETMASK, &oblock, NULL);
65		execv(_PATH_ULOG_HELPER, __DECONST(char * const *, argv));
66		exit(EX_UNAVAILABLE);
67	default:
68		/* Wait for helper to finish. */
69		do {
70			wpid = waitpid(pid, &status, 0);
71		} while (wpid == -1 && errno == EINTR);
72		break;
73	}
74
75	sigprocmask(SIG_SETMASK, &oblock, NULL);
76}
77
78void
79ulog_login_pseudo(int fd, const char *host)
80{
81	char const * const args[4] = { "ulog-helper", "login", host, NULL };
82
83	ulog_exec_helper(fd, args);
84}
85
86void
87ulog_logout_pseudo(int fd)
88{
89	char const * const args[3] = { "ulog-helper", "logout", NULL };
90
91	ulog_exec_helper(fd, args);
92}
93