1 /* 2 * Copyright (C) 2007 Red Hat. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/string.h> 21 #include <linux/xattr.h> 22 #include <linux/posix_acl_xattr.h> 23 #include <linux/posix_acl.h> 24 #include <linux/sched.h> 25 #include <linux/slab.h> 26 27 #include "ctree.h" 28 #include "btrfs_inode.h" 29 #include "xattr.h" 30 31 struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 32 { 33 int size; 34 const char *name; 35 char *value = NULL; 36 struct posix_acl *acl; 37 38 if (!IS_POSIXACL(inode)) 39 return NULL; 40 41 acl = get_cached_acl(inode, type); 42 if (acl != ACL_NOT_CACHED) 43 return acl; 44 45 switch (type) { 46 case ACL_TYPE_ACCESS: 47 name = POSIX_ACL_XATTR_ACCESS; 48 break; 49 case ACL_TYPE_DEFAULT: 50 name = POSIX_ACL_XATTR_DEFAULT; 51 break; 52 default: 53 BUG(); 54 } 55 56 size = __btrfs_getxattr(inode, name, "", 0); 57 if (size > 0) { 58 value = kzalloc(size, GFP_NOFS); 59 if (!value) 60 return ERR_PTR(-ENOMEM); 61 size = __btrfs_getxattr(inode, name, value, size); 62 if (size > 0) { 63 acl = posix_acl_from_xattr(value, size); 64 if (IS_ERR(acl)) { 65 kfree(value); 66 return acl; 67 } 68 set_cached_acl(inode, type, acl); 69 } 70 kfree(value); 71 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 72 /* FIXME, who returns -ENOENT? I think nobody */ 73 acl = NULL; 74 set_cached_acl(inode, type, acl); 75 } else { 76 acl = ERR_PTR(-EIO); 77 } 78 79 return acl; 80 } 81 82 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name, 83 void *value, size_t size, int type) 84 { 85 struct posix_acl *acl; 86 int ret = 0; 87 88 if (!IS_POSIXACL(dentry->d_inode)) 89 return -EOPNOTSUPP; 90 91 acl = btrfs_get_acl(dentry->d_inode, type); 92 93 if (IS_ERR(acl)) 94 return PTR_ERR(acl); 95 if (acl == NULL) 96 return -ENODATA; 97 ret = posix_acl_to_xattr(acl, value, size); 98 posix_acl_release(acl); 99 100 return ret; 101 } 102 103 /* 104 * Needs to be called with fs_mutex held 105 */ 106 static int btrfs_set_acl(struct btrfs_trans_handle *trans, 107 struct inode *inode, struct posix_acl *acl, int type) 108 { 109 int ret, size = 0; 110 const char *name; 111 char *value = NULL; 112 113 if (acl) { 114 ret = posix_acl_valid(acl); 115 if (ret < 0) 116 return ret; 117 ret = 0; 118 } 119 120 switch (type) { 121 case ACL_TYPE_ACCESS: 122 name = POSIX_ACL_XATTR_ACCESS; 123 if (acl) { 124 ret = posix_acl_equiv_mode(acl, &inode->i_mode); 125 if (ret < 0) 126 return ret; 127 } 128 ret = 0; 129 break; 130 case ACL_TYPE_DEFAULT: 131 if (!S_ISDIR(inode->i_mode)) 132 return acl ? -EINVAL : 0; 133 name = POSIX_ACL_XATTR_DEFAULT; 134 break; 135 default: 136 return -EINVAL; 137 } 138 139 if (acl) { 140 size = posix_acl_xattr_size(acl->a_count); 141 value = kmalloc(size, GFP_NOFS); 142 if (!value) { 143 ret = -ENOMEM; 144 goto out; 145 } 146 147 ret = posix_acl_to_xattr(acl, value, size); 148 if (ret < 0) 149 goto out; 150 } 151 152 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 153 out: 154 kfree(value); 155 156 if (!ret) 157 set_cached_acl(inode, type, acl); 158 159 return ret; 160 } 161 162 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name, 163 const void *value, size_t size, int flags, int type) 164 { 165 int ret; 166 struct posix_acl *acl = NULL; 167 168 if (!inode_owner_or_capable(dentry->d_inode)) 169 return -EPERM; 170 171 if (!IS_POSIXACL(dentry->d_inode)) 172 return -EOPNOTSUPP; 173 174 if (value) { 175 acl = posix_acl_from_xattr(value, size); 176 if (IS_ERR(acl)) 177 return PTR_ERR(acl); 178 179 if (acl) { 180 ret = posix_acl_valid(acl); 181 if (ret) 182 goto out; 183 } 184 } 185 186 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 187 out: 188 posix_acl_release(acl); 189 190 return ret; 191 } 192 193 /* 194 * btrfs_init_acl is already generally called under fs_mutex, so the locking 195 * stuff has been fixed to work with that. If the locking stuff changes, we 196 * need to re-evaluate the acl locking stuff. 197 */ 198 int btrfs_init_acl(struct btrfs_trans_handle *trans, 199 struct inode *inode, struct inode *dir) 200 { 201 struct posix_acl *acl = NULL; 202 int ret = 0; 203 204 /* this happens with subvols */ 205 if (!dir) 206 return 0; 207 208 if (!S_ISLNK(inode->i_mode)) { 209 if (IS_POSIXACL(dir)) { 210 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 211 if (IS_ERR(acl)) 212 return PTR_ERR(acl); 213 } 214 215 if (!acl) 216 inode->i_mode &= ~current_umask(); 217 } 218 219 if (IS_POSIXACL(dir) && acl) { 220 if (S_ISDIR(inode->i_mode)) { 221 ret = btrfs_set_acl(trans, inode, acl, 222 ACL_TYPE_DEFAULT); 223 if (ret) 224 goto failed; 225 } 226 ret = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode); 227 if (ret < 0) 228 return ret; 229 230 if (ret > 0) { 231 /* we need an acl */ 232 ret = btrfs_set_acl(trans, inode, acl, ACL_TYPE_ACCESS); 233 } 234 } 235 failed: 236 posix_acl_release(acl); 237 238 return ret; 239 } 240 241 int btrfs_acl_chmod(struct inode *inode) 242 { 243 struct posix_acl *acl; 244 int ret = 0; 245 246 if (S_ISLNK(inode->i_mode)) 247 return -EOPNOTSUPP; 248 249 if (!IS_POSIXACL(inode)) 250 return 0; 251 252 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 253 if (IS_ERR_OR_NULL(acl)) 254 return PTR_ERR(acl); 255 256 ret = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); 257 if (ret) 258 return ret; 259 ret = btrfs_set_acl(NULL, inode, acl, ACL_TYPE_ACCESS); 260 posix_acl_release(acl); 261 return ret; 262 } 263 264 const struct xattr_handler btrfs_xattr_acl_default_handler = { 265 .prefix = POSIX_ACL_XATTR_DEFAULT, 266 .flags = ACL_TYPE_DEFAULT, 267 .get = btrfs_xattr_acl_get, 268 .set = btrfs_xattr_acl_set, 269 }; 270 271 const struct xattr_handler btrfs_xattr_acl_access_handler = { 272 .prefix = POSIX_ACL_XATTR_ACCESS, 273 .flags = ACL_TYPE_ACCESS, 274 .get = btrfs_xattr_acl_get, 275 .set = btrfs_xattr_acl_set, 276 }; 277