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_conn *fc = get_fuse_conn(inode);
  18         FUSE_ARGS(args);
  19         struct fuse_setxattr_in inarg;
  20         int err;
  21
  22         if (fc->no_setxattr)
  23                 return -EOPNOTSUPP;
  24
  25         memset(&inarg, 0, sizeof(inarg));
  26         inarg.size = size;
  27         inarg.flags = flags;
  28         args.in.h.opcode = FUSE_SETXATTR;
  29         args.in.h.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(fc, &args);
  38         if (err == -ENOSYS) {
  39                 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_conn *fc = get_fuse_conn(inode);
  53         FUSE_ARGS(args);
  54         struct fuse_getxattr_in inarg;
  55         struct fuse_getxattr_out outarg;
  56         ssize_t ret;
  57
  58         if (fc->no_getxattr)
  59                 return -EOPNOTSUPP;
  60
  61         memset(&inarg, 0, sizeof(inarg));
  62         inarg.size = size;
  63         args.in.h.opcode = FUSE_GETXATTR;
  64         args.in.h.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 = 1;
  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(fc, &args);
  81         if (!ret && !size)
  82                 ret = min_t(ssize_t, outarg.size, XATTR_SIZE_MAX);
  83         if (ret == -ENOSYS) {
  84                 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_conn *fc = get_fuse_conn(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_allow_current_process(fc))
 117                 return -EACCES;
 118
 119         if (fc->no_listxattr)
 120                 return -EOPNOTSUPP;
 121
 122         memset(&inarg, 0, sizeof(inarg));
 123         inarg.size = size;
 124         args.in.h.opcode = FUSE_LISTXATTR;
 125         args.in.h.nodeid = get_node_id(inode);
 126         args.in.numargs = 1;
 127         args.in.args[0].size = sizeof(inarg);
 128         args.in.args[0].value = &inarg;
 129         /* This is really two different operations rolled into one */
 130         args.out.numargs = 1;
 131         if (size) {
 132                 args.out.argvar = 1;
 133                 args.out.args[0].size = size;
 134                 args.out.args[0].value = list;
 135         } else {
 136                 args.out.args[0].size = sizeof(outarg);
 137                 args.out.args[0].value = &outarg;
 138         }
 139         ret = fuse_simple_request(fc, &args);
 140         if (!ret && !size)
 141                 ret = min_t(ssize_t, outarg.size, XATTR_LIST_MAX);
 142         if (ret > 0 && size)
 143                 ret = fuse_verify_xattr_list(list, ret);
 144         if (ret == -ENOSYS) {
 145                 fc->no_listxattr = 1;
 146                 ret = -EOPNOTSUPP;
 147         }
 148         return ret;
 149 }
 150
 151 int fuse_removexattr(struct inode *inode, const char *name)
 152 {
 153         struct fuse_conn *fc = get_fuse_conn(inode);
 154         FUSE_ARGS(args);
 155         int err;
 156
 157         if (fc->no_removexattr)
 158                 return -EOPNOTSUPP;
 159
 160         args.in.h.opcode = FUSE_REMOVEXATTR;
 161         args.in.h.nodeid = get_node_id(inode);
 162         args.in.numargs = 1;
 163         args.in.args[0].size = strlen(name) + 1;
 164         args.in.args[0].value = name;
 165         err = fuse_simple_request(fc, &args);
 166         if (err == -ENOSYS) {
 167                 fc->no_removexattr = 1;
 168                 err = -EOPNOTSUPP;
 169         }
 170         if (!err) {
 171                 fuse_invalidate_attr(inode);
 172                 fuse_update_ctime(inode);
 173         }
 174         return err;
 175 }
 176
 177 static int fuse_xattr_get(const struct xattr_handler *handler,
 178                          struct dentry *dentry, struct inode *inode,
 179                          const char *name, void *value, size_t size)
 180 {
 181         return fuse_getxattr(inode, name, value, size);
 182 }
 183
 184 static int fuse_xattr_set(const struct xattr_handler *handler,
 185                           struct dentry *dentry, struct inode *inode,
 186                           const char *name, const void *value, size_t size,
 187                           int flags)
 188 {
 189         if (!value)
 190                 return fuse_removexattr(inode, name);
 191
 192         return fuse_setxattr(inode, name, value, size, flags);
 193 }
 194
 195 static const struct xattr_handler fuse_xattr_handler = {
 196         .prefix = "",
 197         .get    = fuse_xattr_get,
 198         .set    = fuse_xattr_set,
 199 };
 200
 201 const struct xattr_handler *fuse_xattr_handlers[] = {
 202         &fuse_xattr_handler,
 203         NULL
 204 };
 205
 206 const struct xattr_handler *fuse_acl_xattr_handlers[] = {
 207         &posix_acl_access_xattr_handler,
 208         &posix_acl_default_xattr_handler,
 209         &fuse_xattr_handler,
 210         NULL
 211 };