1/*	$NetBSD: filemon_dev.c,v 1.3 2020/07/10 15:53:30 sjg Exp $	*/
2
3/*-
4 * Copyright (c) 2020 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include "filemon.h"
33
34#include <sys/ioctl.h>
35
36#include <errno.h>
37#include <fcntl.h>
38#include <stdlib.h>
39#include <unistd.h>
40
41#ifdef HAVE_FILEMON_H
42#  include <filemon.h>
43#endif
44
45#ifndef _PATH_FILEMON
46#define	_PATH_FILEMON	"/dev/filemon"
47#endif
48
49struct filemon {
50	int	fd;
51};
52
53const char *
54filemon_path(void)
55{
56
57	return _PATH_FILEMON;
58}
59
60struct filemon *
61filemon_open(void)
62{
63	struct filemon *F;
64	unsigned i;
65	int error;
66
67	/* Allocate and zero a struct filemon object.  */
68	F = calloc(1, sizeof(*F));
69	if (F == NULL)
70		return NULL;
71
72	/* Try opening /dev/filemon, up to six times (cargo cult!).  */
73	for (i = 0; (F->fd = open(_PATH_FILEMON, O_RDWR|O_CLOEXEC)) == -1; i++) {
74		if (i == 5) {
75			error = errno;
76			goto fail0;
77		}
78	}
79
80	/* Success!  */
81	return F;
82
83fail0:	free(F);
84	errno = error;
85	return NULL;
86}
87
88int
89filemon_setfd(struct filemon *F, int fd)
90{
91
92	/* Point the kernel at this file descriptor.  */
93	if (ioctl(F->fd, FILEMON_SET_FD, &fd) == -1)
94		return -1;
95
96	/* No need for it in userland any more; close it.  */
97	(void)close(fd);
98
99	/* Success!  */
100	return 0;
101}
102
103void
104filemon_setpid_parent(struct filemon *F, pid_t pid)
105{
106	/* Nothing to do!  */
107}
108
109int
110filemon_setpid_child(const struct filemon *F, pid_t pid)
111{
112
113	/* Just pass it on to the kernel.  */
114	return ioctl(F->fd, FILEMON_SET_PID, &pid);
115}
116
117int
118filemon_close(struct filemon *F)
119{
120	int error = 0;
121
122	/* Close the filemon device fd.  */
123	if (close(F->fd) == -1 && error == 0)
124		error = errno;
125
126	/* Free the filemon descriptor.  */
127	free(F);
128
129	/* Set errno and return -1 if anything went wrong.  */
130	if (error) {
131		errno = error;
132		return -1;
133	}
134
135	/* Success!  */
136	return 0;
137}
138
139int
140filemon_readfd(const struct filemon *F)
141{
142
143	return -1;
144}
145
146int
147filemon_process(struct filemon *F)
148{
149
150	return 0;
151}
152