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 <net/9p/9p.h> 12 #include <net/9p/client.h> 13 14 #include "fid.h" 15 #include "xattr.h" 16 17 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, 18 void *buffer, size_t buffer_size) 19 { 20 ssize_t retval; 21 u64 attr_size; 22 struct p9_fid *attr_fid; 23 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size}; 24 struct iov_iter to; 25 int err; 26 27 iov_iter_kvec(&to, READ, &kvec, 1, buffer_size); 28 29 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 30 if (IS_ERR(attr_fid)) { 31 retval = PTR_ERR(attr_fid); 32 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", 33 retval); 34 return retval; 35 } 36 if (attr_size > buffer_size) { 37 if (!buffer_size) /* request to get the attr_size */ 38 retval = attr_size; 39 else 40 retval = -ERANGE; 41 } else { 42 iov_iter_truncate(&to, attr_size); 43 retval = p9_client_read(attr_fid, 0, &to, &err); 44 if (err) 45 retval = err; 46 } 47 p9_fid_put(attr_fid); 48 return retval; 49 } 50 51 52 /* 53 * v9fs_xattr_get() 54 * 55 * Copy an extended attribute into the buffer 56 * provided, or compute the buffer size required. 57 * Buffer is NULL to compute the size of the buffer required. 58 * 59 * Returns a negative error number on failure, or the number of bytes 60 * used / required on success. 61 */ 62 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 63 void *buffer, size_t buffer_size) 64 { 65 struct p9_fid *fid; 66 int ret; 67 68 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n", 69 name, buffer_size); 70 fid = v9fs_fid_lookup(dentry); 71 if (IS_ERR(fid)) 72 return PTR_ERR(fid); 73 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size); 74 p9_fid_put(fid); 75 76 return ret; 77 } 78 79 /* 80 * v9fs_xattr_set() 81 * 82 * Create, replace or remove an extended attribute for this inode. Buffer 83 * is NULL to remove an existing extended attribute, and non-NULL to 84 * either replace an existing extended attribute, or create a new extended 85 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 86 * specify that an extended attribute must exist and must not exist 87 * previous to the call, respectively. 88 * 89 * Returns 0, or a negative error number on failure. 90 */ 91 int v9fs_xattr_set(struct dentry *dentry, const char *name, 92 const void *value, size_t value_len, int flags) 93 { 94 int ret; 95 struct p9_fid *fid; 96 97 fid = v9fs_fid_lookup(dentry); 98 if (IS_ERR(fid)) 99 return PTR_ERR(fid); 100 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags); 101 p9_fid_put(fid); 102 return ret; 103 } 104 105 int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name, 106 const void *value, size_t value_len, int flags) 107 { 108 struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len}; 109 struct iov_iter from; 110 int retval, err; 111 112 iov_iter_kvec(&from, WRITE, &kvec, 1, value_len); 113 114 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n", 115 name, value_len, flags); 116 117 /* Clone it */ 118 fid = clone_fid(fid); 119 if (IS_ERR(fid)) 120 return PTR_ERR(fid); 121 122 /* 123 * On success fid points to xattr 124 */ 125 retval = p9_client_xattrcreate(fid, name, value_len, flags); 126 if (retval < 0) 127 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n", 128 retval); 129 else 130 p9_client_write(fid, 0, &from, &retval); 131 err = p9_fid_put(fid); 132 if (!retval && err) 133 retval = err; 134 return retval; 135 } 136 137 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 138 { 139 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size); 140 } 141 142 static int v9fs_xattr_handler_get(const struct xattr_handler *handler, 143 struct dentry *dentry, struct inode *inode, 144 const char *name, void *buffer, size_t size) 145 { 146 const char *full_name = xattr_full_name(handler, name); 147 148 return v9fs_xattr_get(dentry, full_name, buffer, size); 149 } 150 151 static int v9fs_xattr_handler_set(const struct xattr_handler *handler, 152 struct user_namespace *mnt_userns, 153 struct dentry *dentry, struct inode *inode, 154 const char *name, const void *value, 155 size_t size, int flags) 156 { 157 const char *full_name = xattr_full_name(handler, name); 158 159 return v9fs_xattr_set(dentry, full_name, value, size, flags); 160 } 161 162 static struct xattr_handler v9fs_xattr_user_handler = { 163 .prefix = XATTR_USER_PREFIX, 164 .get = v9fs_xattr_handler_get, 165 .set = v9fs_xattr_handler_set, 166 }; 167 168 static struct xattr_handler v9fs_xattr_trusted_handler = { 169 .prefix = XATTR_TRUSTED_PREFIX, 170 .get = v9fs_xattr_handler_get, 171 .set = v9fs_xattr_handler_set, 172 }; 173 174 #ifdef CONFIG_9P_FS_SECURITY 175 static struct xattr_handler v9fs_xattr_security_handler = { 176 .prefix = XATTR_SECURITY_PREFIX, 177 .get = v9fs_xattr_handler_get, 178 .set = v9fs_xattr_handler_set, 179 }; 180 #endif 181 182 const struct xattr_handler *v9fs_xattr_handlers[] = { 183 &v9fs_xattr_user_handler, 184 &v9fs_xattr_trusted_handler, 185 #ifdef CONFIG_9P_FS_POSIX_ACL 186 &v9fs_xattr_acl_access_handler, 187 &v9fs_xattr_acl_default_handler, 188 #endif 189 #ifdef CONFIG_9P_FS_SECURITY 190 &v9fs_xattr_security_handler, 191 #endif 192 NULL 193 }; 194