1 /* $NetBSD: filemon_dev.c,v 1.8 2021/02/01 21:09:25 rillig 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 struct filemon {
50 int fd;
51 };
52
53 const char *
filemon_path(void)54 filemon_path(void)
55 {
56
57 return _PATH_FILEMON;
58 }
59
60 struct filemon *
filemon_open(void)61 filemon_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
83 fail0: free(F);
84 errno = error;
85 return NULL;
86 }
87
88 int
filemon_setfd(struct filemon * F,int fd)89 filemon_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
103 void
filemon_setpid_parent(struct filemon * F,pid_t pid)104 filemon_setpid_parent(struct filemon *F, pid_t pid)
105 {
106 /* Nothing to do! */
107 }
108
109 int
filemon_setpid_child(const struct filemon * F,pid_t pid)110 filemon_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
117 int
filemon_close(struct filemon * F)118 filemon_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 != 0) {
131 errno = error;
132 return -1;
133 }
134
135 /* Success! */
136 return 0;
137 }
138
139 int
filemon_readfd(const struct filemon * F)140 filemon_readfd(const struct filemon *F)
141 {
142
143 return -1;
144 }
145
146 int
filemon_process(struct filemon * F)147 filemon_process(struct filemon *F)
148 {
149
150 return 0;
151 }
152