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