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 46 struct dirlistent { 47 char *dir; 48 int refcnt; 49 LIST_ENTRY(dirlistent) link; 50 }; 51 52 static LIST_HEAD(, dirlistent) devfs_dirlist = 53 LIST_HEAD_INITIALIZER(devfs_dirlist); 54 55 static MALLOC_DEFINE(M_DEVFS4, "DEVFS4", "DEVFS directory list"); 56 57 static struct mtx dirlist_mtx; 58 MTX_SYSINIT(dirlist_mtx, &dirlist_mtx, "devfs dirlist lock", MTX_DEF); 59 60 /* Returns 1 if the path is in the directory list. */ 61 int 62 devfs_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 78 static struct dirlistent * 79 devfs_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 93 static void 94 devfs_dir_ref(const char *dir) 95 { 96 struct dirlistent *dle, *dle_new; 97 98 if (*dir == '\0') 99 return; 100 101 mtx_lock(&dirlist_mtx); 102 dle = devfs_dir_findent_locked(dir); 103 if (dle != NULL) { 104 dle->refcnt++; 105 mtx_unlock(&dirlist_mtx); 106 return; 107 } 108 109 dle_new = malloc(sizeof(*dle), M_DEVFS4, M_WAITOK); 110 dle_new->dir = strdup(dir, M_DEVFS4); 111 dle_new->refcnt = 1; 112 113 LIST_INSERT_HEAD(&devfs_dirlist, dle_new, link); 114 mtx_unlock(&dirlist_mtx); 115 } 116 117 void 118 devfs_dir_ref_de(struct devfs_mount *dm, struct devfs_dirent *de) 119 { 120 char dirname[SPECNAMELEN + 1], *namep; 121 122 namep = devfs_fqpn(dirname, dm, de, NULL); 123 KASSERT(namep != NULL, ("devfs_ref_dir_de: NULL namep")); 124 125 devfs_dir_ref(namep); 126 } 127 128 static void 129 devfs_dir_unref(const char *dir) 130 { 131 struct dirlistent *dle; 132 133 if (*dir == '\0') 134 return; 135 136 mtx_lock(&dirlist_mtx); 137 dle = devfs_dir_findent_locked(dir); 138 KASSERT(dle != NULL, ("devfs_dir_unref: dir %s not referenced", dir)); 139 dle->refcnt--; 140 KASSERT(dle->refcnt >= 0, ("devfs_dir_unref: negative refcnt")); 141 if (dle->refcnt == 0) { 142 LIST_REMOVE(dle, link); 143 mtx_unlock(&dirlist_mtx); 144 free(dle->dir, M_DEVFS4); 145 free(dle, M_DEVFS4); 146 } else 147 mtx_unlock(&dirlist_mtx); 148 } 149 150 void 151 devfs_dir_unref_de(struct devfs_mount *dm, struct devfs_dirent *de) 152 { 153 char dirname[SPECNAMELEN + 1], *namep; 154 155 namep = devfs_fqpn(dirname, dm, de, NULL); 156 KASSERT(namep != NULL, ("devfs_unref_dir_de: NULL namep")); 157 158 devfs_dir_unref(namep); 159 } 160 161 /* Returns 1 if the path p1 contains the path p2. */ 162 int 163 devfs_pathpath(const char *p1, const char *p2) 164 { 165 166 for (;;p1++, p2++) { 167 if (*p1 != *p2) { 168 if (*p1 == '/' && *p2 == '\0') 169 return (1); 170 else 171 return (0); 172 } else if (*p1 == '\0') 173 return (1); 174 } 175 /* NOTREACHED */ 176 } 177