1 // SPDX-License-Identifier: LGPL-2.1 2 /* 3 * Copyright IBM Corporation, 2010 4 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 5 */ 6 7 #include <linux/module.h> 8 #include <linux/fs.h> 9 #include <linux/sched.h> 10 #include <linux/uio.h> 11 #include <linux/posix_acl_xattr.h> 12 #include <net/9p/9p.h> 13 #include <net/9p/client.h> 14 15 #include "fid.h" 16 #include "xattr.h" 17 18 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, 19 void *buffer, size_t buffer_size) 20 { 21 ssize_t retval; 22 u64 attr_size; 23 struct p9_fid *attr_fid; 24 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size}; 25 struct iov_iter to; 26 int err; 27 28 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size); 29 30 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 31 if (IS_ERR(attr_fid)) { 32 retval = PTR_ERR(attr_fid); 33 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", 34 retval); 35 return retval; 36 } 37 if (attr_size > buffer_size) { 38 if (!buffer_size) /* request to get the attr_size */ 39 retval = attr_size; 40 else 41 retval = -ERANGE; 42 } else { 43 iov_iter_truncate(&to, attr_size); 44 retval = p9_client_read(attr_fid, 0, &to, &err); 45 if (err) 46 retval = err; 47 } 48 p9_fid_put(attr_fid); 49 return retval; 50 } 51 52 53 /* 54 * v9fs_xattr_get() 55 * 56 * Copy an extended attribute into the buffer 57 * provided, or compute the buffer size required. 58 * Buffer is NULL to compute the size of the buffer required. 59 * 60 * Returns a negative error number on failure, or the number of bytes 61 * used / required on success. 62 */ 63 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 64 void *buffer, size_t buffer_size) 65 { 66 struct p9_fid *fid; 67 int ret; 68 69 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n", 70 name, buffer_size); 71 fid = v9fs_fid_lookup(dentry); 72 if (IS_ERR(fid)) 73 return PTR_ERR(fid); 74 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size); 75 p9_fid_put(fid); 76 77 return ret; 78 } 79 80 /* 81 * v9fs_xattr_set() 82 * 83 * Create, replace or remove an extended attribute for this inode. Buffer 84 * is NULL to remove an existing extended attribute, and non-NULL to 85 * either replace an existing extended attribute, or create a new extended 86 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 87 * specify that an extended attribute must exist and must not exist 88 * previous to the call, respectively. 89 * 90 * Returns 0, or a negative error number on failure. 91 */ 92 int v9fs_xattr_set(struct dentry *dentry, const char *name, 93 const void *value, size_t value_len, int flags) 94 { 95 int ret; 96 struct p9_fid *fid; 97 98 fid = v9fs_fid_lookup(dentry); 99 if (IS_ERR(fid)) 100 return PTR_ERR(fid); 101 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags); 102 p9_fid_put(fid); 103 return ret; 104 } 105 106 int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name, 107 const void *value, size_t value_len, int flags) 108 { 109 struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len}; 110 struct iov_iter from; 111 int retval, err; 112 113 iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len); 114 115 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n", 116 name, value_len, flags); 117 118 /* Clone it */ 119 fid = clone_fid(fid); 120 if (IS_ERR(fid)) 121 return PTR_ERR(fid); 122 123 /* 124 * On success fid points to xattr 125 */ 126 retval = p9_client_xattrcreate(fid, name, value_len, flags); 127 if (retval < 0) 128 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n", 129 retval); 130 else 131 p9_client_write(fid, 0, &from, &retval); 132 err = p9_fid_put(fid); 133 if (!retval && err) 134 retval = err; 135 return retval; 136 } 137 138 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 139 { 140 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size); 141 } 142 143 static int v9fs_xattr_handler_get(const struct xattr_handler *handler, 144 struct dentry *dentry, struct inode *inode, 145 const char *name, void *buffer, size_t size) 146 { 147 const char *full_name = xattr_full_name(handler, name); 148 149 return v9fs_xattr_get(dentry, full_name, buffer, size); 150 } 151 152 static int v9fs_xattr_handler_set(const struct xattr_handler *handler, 153 struct user_namespace *mnt_userns, 154 struct dentry *dentry, struct inode *inode, 155 const char *name, const void *value, 156 size_t size, int flags) 157 { 158 const char *full_name = xattr_full_name(handler, name); 159 160 return v9fs_xattr_set(dentry, full_name, value, size, flags); 161 } 162 163 static struct xattr_handler v9fs_xattr_user_handler = { 164 .prefix = XATTR_USER_PREFIX, 165 .get = v9fs_xattr_handler_get, 166 .set = v9fs_xattr_handler_set, 167 }; 168 169 static struct xattr_handler v9fs_xattr_trusted_handler = { 170 .prefix = XATTR_TRUSTED_PREFIX, 171 .get = v9fs_xattr_handler_get, 172 .set = v9fs_xattr_handler_set, 173 }; 174 175 #ifdef CONFIG_9P_FS_SECURITY 176 static struct xattr_handler v9fs_xattr_security_handler = { 177 .prefix = XATTR_SECURITY_PREFIX, 178 .get = v9fs_xattr_handler_get, 179 .set = v9fs_xattr_handler_set, 180 }; 181 #endif 182 183 const struct xattr_handler *v9fs_xattr_handlers[] = { 184 &v9fs_xattr_user_handler, 185 &v9fs_xattr_trusted_handler, 186 #ifdef CONFIG_FS_POSIX_ACL 187 &posix_acl_access_xattr_handler, 188 &posix_acl_default_xattr_handler, 189 #endif 190 #ifdef CONFIG_9P_FS_SECURITY 191 &v9fs_xattr_security_handler, 192 #endif 193 NULL 194 }; 195