fs/fuse/xattr.c

   1 /*
   2  * FUSE: Filesystem in Userspace
   3  * Copyright (C) 2001-2016  Miklos Szeredi <miklos@szeredi.hu>
   4  *
   5  * This program can be distributed under the terms of the GNU GPL.
   6  * See the file COPYING.
   7  */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/xattr.h>
  12 #include <linux/posix_acl_xattr.h>
  13
  14 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
  15                   size_t size, int flags)
  16 {
  17         struct fuse_mount *fm = get_fuse_mount(inode);
  18         FUSE_ARGS(args);
  19         struct fuse_setxattr_in inarg;
  20         int err;
  21
  22         if (fm->fc->no_setxattr)
  23                 return -EOPNOTSUPP;
  24
  25         memset(&inarg, 0, sizeof(inarg));
  26         inarg.size = size;
  27         inarg.flags = flags;
  28         args.opcode = FUSE_SETXATTR;
  29         args.nodeid = get_node_id(inode);
  30         args.in_numargs = 3;
  31         args.in_args[0].size = sizeof(inarg);
  32         args.in_args[0].value = &inarg;
  33         args.in_args[1].size = strlen(name) + 1;
  34         args.in_args[1].value = name;
  35         args.in_args[2].size = size;
  36         args.in_args[2].value = value;
  37         err = fuse_simple_request(fm, &args);
  38         if (err == -ENOSYS) {
  39                 fm->fc->no_setxattr = 1;
  40                 err = -EOPNOTSUPP;
  41         }
  42         if (!err) {
  43                 fuse_invalidate_attr(inode);
  44                 fuse_update_ctime(inode);
  45         }
  46         return err;
  47 }
  48
  49 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
  50                       size_t size)
  51 {
  52         struct fuse_mount *fm = get_fuse_mount(inode);
  53         FUSE_ARGS(args);
  54         struct fuse_getxattr_in inarg;
  55         struct fuse_getxattr_out outarg;
  56         ssize_t ret;
  57
  58         if (fm->fc->no_getxattr)
  59                 return -EOPNOTSUPP;
  60
  61         memset(&inarg, 0, sizeof(inarg));
  62         inarg.size = size;
  63         args.opcode = FUSE_GETXATTR;
  64         args.nodeid = get_node_id(inode);
  65         args.in_numargs = 2;
  66         args.in_args[0].size = sizeof(inarg);
  67         args.in_args[0].value = &inarg;
  68         args.in_args[1].size = strlen(name) + 1;
  69         args.in_args[1].value = name;
  70         /* This is really two different operations rolled into one */
  71         args.out_numargs = 1;
  72         if (size) {
  73                 args.out_argvar = true;
  74                 args.out_args[0].size = size;
  75                 args.out_args[0].value = value;
  76         } else {
  77                 args.out_args[0].size = sizeof(outarg);
  78                 args.out_args[0].value = &outarg;
  79         }
  80         ret = fuse_simple_request(fm, &args);
  81         if (!ret && !size)
  82                 ret = min_t(ssize_t, outarg.size, XATTR_SIZE_MAX);
  83         if (ret == -ENOSYS) {
  84                 fm->fc->no_getxattr = 1;
  85                 ret = -EOPNOTSUPP;
  86         }
  87         return ret;
  88 }
  89
  90 static int fuse_verify_xattr_list(char *list, size_t size)
  91 {
  92         size_t origsize = size;
  93
  94         while (size) {
  95                 size_t thislen = strnlen(list, size);
  96
  97                 if (!thislen || thislen == size)
  98                         return -EIO;
  99
 100                 size -= thislen + 1;
 101                 list += thislen + 1;
 102         }
 103
 104         return origsize;
 105 }
 106
 107 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 108 {
 109         struct inode *inode = d_inode(entry);
 110         struct fuse_mount *fm = get_fuse_mount(inode);
 111         FUSE_ARGS(args);
 112         struct fuse_getxattr_in inarg;
 113         struct fuse_getxattr_out outarg;
 114         ssize_t ret;
 115
 116         if (fuse_is_bad(inode))
 117                 return -EIO;
 118
 119         if (!fuse_allow_current_process(fm->fc))
 120                 return -EACCES;
 121
 122         if (fm->fc->no_listxattr)
 123                 return -EOPNOTSUPP;
 124
 125         memset(&inarg, 0, sizeof(inarg));
 126         inarg.size = size;
 127         args.opcode = FUSE_LISTXATTR;
 128         args.nodeid = get_node_id(inode);
 129         args.in_numargs = 1;
 130         args.in_args[0].size = sizeof(inarg);
 131         args.in_args[0].value = &inarg;
 132         /* This is really two different operations rolled into one */
 133         args.out_numargs = 1;
 134         if (size) {
 135                 args.out_argvar = true;
 136                 args.out_args[0].size = size;
 137                 args.out_args[0].value = list;
 138         } else {
 139                 args.out_args[0].size = sizeof(outarg);
 140                 args.out_args[0].value = &outarg;
 141         }
 142         ret = fuse_simple_request(fm, &args);
 143         if (!ret && !size)
 144                 ret = min_t(ssize_t, outarg.size, XATTR_LIST_MAX);
 145         if (ret > 0 && size)
 146                 ret = fuse_verify_xattr_list(list, ret);
 147         if (ret == -ENOSYS) {
 148                 fm->fc->no_listxattr = 1;
 149                 ret = -EOPNOTSUPP;
 150         }
 151         return ret;
 152 }
 153
 154 int fuse_removexattr(struct inode *inode, const char *name)
 155 {
 156         struct fuse_mount *fm = get_fuse_mount(inode);
 157         FUSE_ARGS(args);
 158         int err;
 159
 160         if (fm->fc->no_removexattr)
 161                 return -EOPNOTSUPP;
 162
 163         args.opcode = FUSE_REMOVEXATTR;
 164         args.nodeid = get_node_id(inode);
 165         args.in_numargs = 1;
 166         args.in_args[0].size = strlen(name) + 1;
 167         args.in_args[0].value = name;
 168         err = fuse_simple_request(fm, &args);
 169         if (err == -ENOSYS) {
 170                 fm->fc->no_removexattr = 1;
 171                 err = -EOPNOTSUPP;
 172         }
 173         if (!err) {
 174                 fuse_invalidate_attr(inode);
 175                 fuse_update_ctime(inode);
 176         }
 177         return err;
 178 }
 179
 180 static int fuse_xattr_get(const struct xattr_handler *handler,
 181                          struct dentry *dentry, struct inode *inode,
 182                          const char *name, void *value, size_t size)
 183 {
 184         if (fuse_is_bad(inode))
 185                 return -EIO;
 186
 187         return fuse_getxattr(inode, name, value, size);
 188 }
 189
 190 static int fuse_xattr_set(const struct xattr_handler *handler,
 191                           struct dentry *dentry, struct inode *inode,
 192                           const char *name, const void *value, size_t size,
 193                           int flags)
 194 {
 195         if (fuse_is_bad(inode))
 196                 return -EIO;
 197
 198         if (!value)
 199                 return fuse_removexattr(inode, name);
 200
 201         return fuse_setxattr(inode, name, value, size, flags);
 202 }
 203
 204 static bool no_xattr_list(struct dentry *dentry)
 205 {
 206         return false;
 207 }
 208
 209 static int no_xattr_get(const struct xattr_handler *handler,
 210                         struct dentry *dentry, struct inode *inode,
 211                         const char *name, void *value, size_t size)
 212 {
 213         return -EOPNOTSUPP;
 214 }
 215
 216 static int no_xattr_set(const struct xattr_handler *handler,
 217                         struct dentry *dentry, struct inode *nodee,
 218                         const char *name, const void *value,
 219                         size_t size, int flags)
 220 {
 221         return -EOPNOTSUPP;
 222 }
 223
 224 static const struct xattr_handler fuse_xattr_handler = {
 225         .prefix = "",
 226         .get    = fuse_xattr_get,
 227         .set    = fuse_xattr_set,
 228 };
 229
 230 const struct xattr_handler *fuse_xattr_handlers[] = {
 231         &fuse_xattr_handler,
 232         NULL
 233 };
 234
 235 const struct xattr_handler *fuse_acl_xattr_handlers[] = {
 236         &posix_acl_access_xattr_handler,
 237         &posix_acl_default_xattr_handler,
 238         &fuse_xattr_handler,
 239         NULL
 240 };
 241
 242 static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
 243         .name  = XATTR_NAME_POSIX_ACL_ACCESS,
 244         .flags = ACL_TYPE_ACCESS,
 245         .list  = no_xattr_list,
 246         .get   = no_xattr_get,
 247         .set   = no_xattr_set,
 248 };
 249
 250 static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
 251         .name  = XATTR_NAME_POSIX_ACL_DEFAULT,
 252         .flags = ACL_TYPE_ACCESS,
 253         .list  = no_xattr_list,
 254         .get   = no_xattr_get,
 255         .set   = no_xattr_set,
 256 };
 257
 258 const struct xattr_handler *fuse_no_acl_xattr_handlers[] = {
 259         &fuse_no_acl_access_xattr_handler,
 260         &fuse_no_acl_default_xattr_handler,
 261         &fuse_xattr_handler,
 262         NULL
 263 };