hooks.c revision 211884 
1/*-
2 * Copyright (c) 2010 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Pawel Jakub Dawidek under sponsorship from
6 * the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/sbin/hastd/hooks.c 211884 2010-08-27 14:35:39Z pjd $");
32
33#include <sys/types.h>
34#include <sys/wait.h>
35
36#include <assert.h>
37#include <fcntl.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <unistd.h>
41#include <string.h>
42#include <syslog.h>
43#include <libgen.h>
44#include <paths.h>
45
46#include <pjdlog.h>
47
48#include "hooks.h"
49
50static void
51descriptors(void)
52{
53	long maxfd;
54	int fd;
55
56	/*
57	 * Close all descriptors.
58	 */
59	maxfd = sysconf(_SC_OPEN_MAX);
60	if (maxfd < 0) {
61		pjdlog_errno(LOG_WARNING, "sysconf(_SC_OPEN_MAX) failed");
62		maxfd = 1024;
63	}
64	for (fd = 0; fd <= maxfd; fd++) {
65		switch (fd) {
66		case STDIN_FILENO:
67		case STDOUT_FILENO:
68		case STDERR_FILENO:
69			if (pjdlog_mode_get() == PJDLOG_MODE_STD)
70				break;
71			/* FALLTHROUGH */
72		default:
73			close(fd);
74			break;
75		}
76	}
77	if (pjdlog_mode_get() == PJDLOG_MODE_STD)
78		return;
79	/*
80	 * Redirect stdin, stdout and stderr to /dev/null.
81	 */
82	fd = open(_PATH_DEVNULL, O_RDONLY);
83	if (fd < 0) {
84		pjdlog_errno(LOG_WARNING, "Unable to open %s for reading",
85		    _PATH_DEVNULL);
86	} else if (fd != STDIN_FILENO) {
87		if (dup2(fd, STDIN_FILENO) < 0) {
88			pjdlog_errno(LOG_WARNING,
89			    "Unable to duplicate descriptor for stdin");
90		}
91		close(fd);
92	}
93	fd = open(_PATH_DEVNULL, O_WRONLY);
94	if (fd < 0) {
95		pjdlog_errno(LOG_WARNING, "Unable to open %s for writing",
96		    _PATH_DEVNULL);
97	} else {
98		if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) < 0) {
99			pjdlog_errno(LOG_WARNING,
100			    "Unable to duplicate descriptor for stdout");
101		}
102		if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) < 0) {
103			pjdlog_errno(LOG_WARNING,
104			    "Unable to duplicate descriptor for stderr");
105		}
106		if (fd != STDOUT_FILENO && fd != STDERR_FILENO)
107			close(fd);
108	}
109}
110
111int
112hook_exec(const char *path, ...)
113{
114	va_list ap;
115	int ret;
116
117	va_start(ap, path);
118	ret = hook_execv(path, ap);
119	va_end(ap);
120	return (ret);
121}
122
123int
124hook_execv(const char *path, va_list ap)
125{
126	char *args[64];
127	unsigned int ii;
128	pid_t pid, wpid;
129	int status;
130
131	if (path == NULL || path[0] == '\0')
132		return (0);
133
134	memset(args, 0, sizeof(args));
135	args[0] = basename(path);
136	for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) {
137		args[ii] = va_arg(ap, char *);
138		if (args[ii] == NULL)
139			break;
140	}
141	assert(ii < sizeof(args) / sizeof(args[0]));
142
143	pid = fork();
144	switch (pid) {
145	case -1:	/* Error. */
146		pjdlog_errno(LOG_ERR, "Unable to fork %s", path);
147		return (-1);
148	case 0:		/* Child. */
149		descriptors();
150		execv(path, args);
151		pjdlog_errno(LOG_ERR, "Unable to execute %s", path);
152		exit(EX_SOFTWARE);
153	default:	/* Parent. */
154		break;
155	}
156
157	wpid = waitpid(pid, &status, 0);
158	assert(wpid == pid);
159
160	return (WEXITSTATUS(status));
161}
162