1/*	$NetBSD: filemon_dev.c,v 1.9 2022/03/04 23:17:16 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
49#ifndef MAKE_ATTR_UNUSED
50#define MAKE_ATTR_UNUSED        __attribute__((__unused__))
51#endif
52
53struct filemon {
54	int	fd;
55};
56
57const char *
58filemon_path(void)
59{
60
61	return _PATH_FILEMON;
62}
63
64struct filemon *
65filemon_open(void)
66{
67	struct filemon *F;
68	unsigned i;
69	int error;
70
71	/* Allocate and zero a struct filemon object.  */
72	F = calloc(1, sizeof *F);
73	if (F == NULL)
74		return NULL;
75
76	/* Try opening /dev/filemon, up to six times (cargo cult!).  */
77	for (i = 0; (F->fd = open(_PATH_FILEMON, O_RDWR|O_CLOEXEC)) == -1; i++) {
78		if (i == 5) {
79			error = errno;
80			goto fail0;
81		}
82	}
83
84	/* Success!  */
85	return F;
86
87fail0:	free(F);
88	errno = error;
89	return NULL;
90}
91
92int
93filemon_setfd(struct filemon *F, int fd)
94{
95
96	/* Point the kernel at this file descriptor.  */
97	if (ioctl(F->fd, FILEMON_SET_FD, &fd) == -1)
98		return -1;
99
100	/* No need for it in userland any more; close it.  */
101	(void)close(fd);
102
103	/* Success!  */
104	return 0;
105}
106
107void
108filemon_setpid_parent(struct filemon *F MAKE_ATTR_UNUSED, pid_t pid MAKE_ATTR_UNUSED)
109{
110	/* Nothing to do!  */
111}
112
113int
114filemon_setpid_child(const struct filemon *F, pid_t pid)
115{
116
117	/* Just pass it on to the kernel.  */
118	return ioctl(F->fd, FILEMON_SET_PID, &pid);
119}
120
121int
122filemon_close(struct filemon *F)
123{
124	int error = 0;
125
126	/* Close the filemon device fd.  */
127	if (close(F->fd) == -1 && error == 0)
128		error = errno;
129
130	/* Free the filemon descriptor.  */
131	free(F);
132
133	/* Set errno and return -1 if anything went wrong.  */
134	if (error != 0) {
135		errno = error;
136		return -1;
137	}
138
139	/* Success!  */
140	return 0;
141}
142
143int
144filemon_readfd(const struct filemon *F MAKE_ATTR_UNUSED)
145{
146
147	return -1;
148}
149
150int
151filemon_process(struct filemon *F MAKE_ATTR_UNUSED)
152{
153
154	return 0;
155}
156