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 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 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 * 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 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 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 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 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 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