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, unsigned int extra_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         inarg.setxattr_flags = extra_flags;
  29
  30         args.opcode = FUSE_SETXATTR;
  31         args.nodeid = get_node_id(inode);
  32         args.in_numargs = 3;
  33         args.in_args[0].size = fm->fc->setxattr_ext ?
  34                 sizeof(inarg) : FUSE_COMPAT_SETXATTR_IN_SIZE;
  35         args.in_args[0].value = &inarg;
  36         args.in_args[1].size = strlen(name) + 1;
  37         args.in_args[1].value = name;
  38         args.in_args[2].size = size;
  39         args.in_args[2].value = value;
  40         err = fuse_simple_request(fm, &args);
  41         if (err == -ENOSYS) {
  42                 fm->fc->no_setxattr = 1;
  43                 err = -EOPNOTSUPP;
  44         }
  45         if (!err)
  46                 fuse_update_ctime(inode);
  47
  48         return err;
  49 }
  50
  51 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
  52                       size_t size)
  53 {
  54         struct fuse_mount *fm = get_fuse_mount(inode);
  55         FUSE_ARGS(args);
  56         struct fuse_getxattr_in inarg;
  57         struct fuse_getxattr_out outarg;
  58         ssize_t ret;
  59
  60         if (fm->fc->no_getxattr)
  61                 return -EOPNOTSUPP;
  62
  63         memset(&inarg, 0, sizeof(inarg));
  64         inarg.size = size;
  65         args.opcode = FUSE_GETXATTR;
  66         args.nodeid = get_node_id(inode);
  67         args.in_numargs = 2;
  68         args.in_args[0].size = sizeof(inarg);
  69         args.in_args[0].value = &inarg;
  70         args.in_args[1].size = strlen(name) + 1;
  71         args.in_args[1].value = name;
  72         /* This is really two different operations rolled into one */
  73         args.out_numargs = 1;
  74         if (size) {
  75                 args.out_argvar = true;
  76                 args.out_args[0].size = size;
  77                 args.out_args[0].value = value;
  78         } else {
  79                 args.out_args[0].size = sizeof(outarg);
  80                 args.out_args[0].value = &outarg;
  81         }
  82         ret = fuse_simple_request(fm, &args);
  83         if (!ret && !size)
  84                 ret = min_t(size_t, outarg.size, XATTR_SIZE_MAX);
  85         if (ret == -ENOSYS) {
  86                 fm->fc->no_getxattr = 1;
  87                 ret = -EOPNOTSUPP;
  88         }
  89         return ret;
  90 }
  91
  92 static int fuse_verify_xattr_list(char *list, size_t size)
  93 {
  94         size_t origsize = size;
  95
  96         while (size) {
  97                 size_t thislen = strnlen(list, size);
  98
  99                 if (!thislen || thislen == size)
 100                         return -EIO;
 101
 102                 size -= thislen + 1;
 103                 list += thislen + 1;
 104         }
 105
 106         return origsize;
 107 }
 108
 109 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 110 {
 111         struct inode *inode = d_inode(entry);
 112         struct fuse_mount *fm = get_fuse_mount(inode);
 113         FUSE_ARGS(args);
 114         struct fuse_getxattr_in inarg;
 115         struct fuse_getxattr_out outarg;
 116         ssize_t ret;
 117
 118         if (fuse_is_bad(inode))
 119                 return -EIO;
 120
 121         if (!fuse_allow_current_process(fm->fc))
 122                 return -EACCES;
 123
 124         if (fm->fc->no_listxattr)
 125                 return -EOPNOTSUPP;
 126
 127         memset(&inarg, 0, sizeof(inarg));
 128         inarg.size = size;
 129         args.opcode = FUSE_LISTXATTR;
 130         args.nodeid = get_node_id(inode);
 131         args.in_numargs = 1;
 132         args.in_args[0].size = sizeof(inarg);
 133         args.in_args[0].value = &inarg;
 134         /* This is really two different operations rolled into one */
 135         args.out_numargs = 1;
 136         if (size) {
 137                 args.out_argvar = true;
 138                 args.out_args[0].size = size;
 139                 args.out_args[0].value = list;
 140         } else {
 141                 args.out_args[0].size = sizeof(outarg);
 142                 args.out_args[0].value = &outarg;
 143         }
 144         ret = fuse_simple_request(fm, &args);
 145         if (!ret && !size)
 146                 ret = min_t(size_t, outarg.size, XATTR_LIST_MAX);
 147         if (ret > 0 && size)
 148                 ret = fuse_verify_xattr_list(list, ret);
 149         if (ret == -ENOSYS) {
 150                 fm->fc->no_listxattr = 1;
 151                 ret = -EOPNOTSUPP;
 152         }
 153         return ret;
 154 }
 155
 156 int fuse_removexattr(struct inode *inode, const char *name)
 157 {
 158         struct fuse_mount *fm = get_fuse_mount(inode);
 159         FUSE_ARGS(args);
 160         int err;
 161
 162         if (fm->fc->no_removexattr)
 163                 return -EOPNOTSUPP;
 164
 165         args.opcode = FUSE_REMOVEXATTR;
 166         args.nodeid = get_node_id(inode);
 167         args.in_numargs = 1;
 168         args.in_args[0].size = strlen(name) + 1;
 169         args.in_args[0].value = name;
 170         err = fuse_simple_request(fm, &args);
 171         if (err == -ENOSYS) {
 172                 fm->fc->no_removexattr = 1;
 173                 err = -EOPNOTSUPP;
 174         }
 175         if (!err)
 176                 fuse_update_ctime(inode);
 177
 178         return err;
 179 }
 180
 181 static int fuse_xattr_get(const struct xattr_handler *handler,
 182                          struct dentry *dentry, struct inode *inode,
 183                          const char *name, void *value, size_t size)
 184 {
 185         if (fuse_is_bad(inode))
 186                 return -EIO;
 187
 188         return fuse_getxattr(inode, name, value, size);
 189 }
 190
 191 static int fuse_xattr_set(const struct xattr_handler *handler,
 192                           struct mnt_idmap *idmap,
 193                           struct dentry *dentry, struct inode *inode,
 194                           const char *name, const void *value, size_t size,
 195                           int flags)
 196 {
 197         if (fuse_is_bad(inode))
 198                 return -EIO;
 199
 200         if (!value)
 201                 return fuse_removexattr(inode, name);
 202
 203         return fuse_setxattr(inode, name, value, size, flags, 0);
 204 }
 205
 206 static const struct xattr_handler fuse_xattr_handler = {
 207         .prefix = "",
 208         .get    = fuse_xattr_get,
 209         .set    = fuse_xattr_set,
 210 };
 211
 212 const struct xattr_handler * const fuse_xattr_handlers[] = {
 213         &fuse_xattr_handler,
 214         NULL
 215 };