1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2010 Jaakko Heinonen <jh@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include <sys/param.h>
32#include <sys/conf.h>
33#include <sys/types.h>
34#include <sys/kernel.h>
35#include <sys/libkern.h>
36#include <sys/lock.h>
37#include <sys/malloc.h>
38#include <sys/mutex.h>
39#include <sys/queue.h>
40#include <sys/systm.h>
41#include <sys/sx.h>
42
43#include <fs/devfs/devfs.h>
44#include <fs/devfs/devfs_int.h>
45
46struct dirlistent {
47	char			*dir;
48	int			refcnt;
49	LIST_ENTRY(dirlistent)	link;
50};
51
52static LIST_HEAD(, dirlistent) devfs_dirlist =
53    LIST_HEAD_INITIALIZER(devfs_dirlist);
54
55static MALLOC_DEFINE(M_DEVFS4, "DEVFS4", "DEVFS directory list");
56
57static struct mtx dirlist_mtx;
58MTX_SYSINIT(dirlist_mtx, &dirlist_mtx, "devfs dirlist lock", MTX_DEF);
59
60/* Returns 1 if the path is in the directory list. */
61int
62devfs_dir_find(const char *path)
63{
64	struct dirlistent *dle;
65
66	mtx_lock(&dirlist_mtx);
67	LIST_FOREACH(dle, &devfs_dirlist, link) {
68		if (devfs_pathpath(dle->dir, path) != 0) {
69			mtx_unlock(&dirlist_mtx);
70			return (1);
71		}
72	}
73	mtx_unlock(&dirlist_mtx);
74
75	return (0);
76}
77
78static struct dirlistent *
79devfs_dir_findent_locked(const char *dir)
80{
81	struct dirlistent *dle;
82
83	mtx_assert(&dirlist_mtx, MA_OWNED);
84
85	LIST_FOREACH(dle, &devfs_dirlist, link) {
86		if (strcmp(dir, dle->dir) == 0)
87			return (dle);
88	}
89
90	return (NULL);
91}
92
93static void
94devfs_dir_ref(const char *dir)
95{
96	struct dirlistent *dle, *dle_new;
97
98	if (*dir == '\0')
99		return;
100
101	dle_new = malloc(sizeof(*dle), M_DEVFS4, M_WAITOK);
102	dle_new->dir = strdup(dir, M_DEVFS4);
103	dle_new->refcnt = 1;
104
105	mtx_lock(&dirlist_mtx);
106	dle = devfs_dir_findent_locked(dir);
107	if (dle != NULL) {
108		dle->refcnt++;
109		mtx_unlock(&dirlist_mtx);
110		free(dle_new->dir, M_DEVFS4);
111		free(dle_new, M_DEVFS4);
112		return;
113	}
114	LIST_INSERT_HEAD(&devfs_dirlist, dle_new, link);
115	mtx_unlock(&dirlist_mtx);
116}
117
118void
119devfs_dir_ref_de(struct devfs_mount *dm, struct devfs_dirent *de)
120{
121	char dirname[SPECNAMELEN + 1], *namep;
122
123	namep = devfs_fqpn(dirname, dm, de, NULL);
124	KASSERT(namep != NULL, ("devfs_ref_dir_de: NULL namep"));
125
126	devfs_dir_ref(namep);
127}
128
129static void
130devfs_dir_unref(const char *dir)
131{
132	struct dirlistent *dle;
133
134	if (*dir == '\0')
135		return;
136
137	mtx_lock(&dirlist_mtx);
138	dle = devfs_dir_findent_locked(dir);
139	KASSERT(dle != NULL, ("devfs_dir_unref: dir %s not referenced", dir));
140	dle->refcnt--;
141	KASSERT(dle->refcnt >= 0, ("devfs_dir_unref: negative refcnt"));
142	if (dle->refcnt == 0) {
143		LIST_REMOVE(dle, link);
144		mtx_unlock(&dirlist_mtx);
145		free(dle->dir, M_DEVFS4);
146		free(dle, M_DEVFS4);
147	} else
148		mtx_unlock(&dirlist_mtx);
149}
150
151void
152devfs_dir_unref_de(struct devfs_mount *dm, struct devfs_dirent *de)
153{
154	char dirname[SPECNAMELEN + 1], *namep;
155
156	namep = devfs_fqpn(dirname, dm, de, NULL);
157	KASSERT(namep != NULL, ("devfs_unref_dir_de: NULL namep"));
158
159	devfs_dir_unref(namep);
160}
161
162/* Returns 1 if the path p1 contains the path p2. */
163int
164devfs_pathpath(const char *p1, const char *p2)
165{
166
167	for (;;p1++, p2++) {
168		if (*p1 != *p2) {
169			if (*p1 == '/' && *p2 == '\0')
170				return (1);
171			else
172				return (0);
173		} else if (*p1 == '\0')
174			return (1);
175	}
176	/* NOTREACHED */
177}
178