1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
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
44 struct dirlistent {
45 char *dir;
46 int refcnt;
47 LIST_ENTRY(dirlistent) link;
48 };
49
50 static LIST_HEAD(, dirlistent) devfs_dirlist =
51 LIST_HEAD_INITIALIZER(devfs_dirlist);
52
53 static MALLOC_DEFINE(M_DEVFS4, "DEVFS4", "DEVFS directory list");
54
55 static struct mtx dirlist_mtx;
56 MTX_SYSINIT(dirlist_mtx, &dirlist_mtx, "devfs dirlist lock", MTX_DEF);
57
58 /* Returns 1 if the path is in the directory list. */
59 int
devfs_dir_find(const char * path)60 devfs_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
76 static struct dirlistent *
devfs_dir_findent_locked(const char * dir)77 devfs_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
91 static void
devfs_dir_ref(const char * dir)92 devfs_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
116 void
devfs_dir_ref_de(struct devfs_mount * dm,struct devfs_dirent * de)117 devfs_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
127 static void
devfs_dir_unref(const char * dir)128 devfs_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
149 void
devfs_dir_unref_de(struct devfs_mount * dm,struct devfs_dirent * de)150 devfs_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. */
161 int
devfs_pathpath(const char * p1,const char * p2)162 devfs_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