1 /* 2 * Copyright IBM Corporation, 2010 3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/fs.h> 17 #include <linux/sched.h> 18 #include <linux/uio.h> 19 #include <net/9p/9p.h> 20 #include <net/9p/client.h> 21 22 #include "fid.h" 23 #include "xattr.h" 24 25 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, 26 void *buffer, size_t buffer_size) 27 { 28 ssize_t retval; 29 u64 attr_size; 30 struct p9_fid *attr_fid; 31 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size}; 32 struct iov_iter to; 33 int err; 34 35 iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buffer_size); 36 37 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 38 if (IS_ERR(attr_fid)) { 39 retval = PTR_ERR(attr_fid); 40 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", 41 retval); 42 return retval; 43 } 44 if (attr_size > buffer_size) { 45 if (!buffer_size) /* request to get the attr_size */ 46 retval = attr_size; 47 else 48 retval = -ERANGE; 49 } else { 50 iov_iter_truncate(&to, attr_size); 51 retval = p9_client_read(attr_fid, 0, &to, &err); 52 if (err) 53 retval = err; 54 } 55 p9_client_clunk(attr_fid); 56 return retval; 57 } 58 59 60 /* 61 * v9fs_xattr_get() 62 * 63 * Copy an extended attribute into the buffer 64 * provided, or compute the buffer size required. 65 * Buffer is NULL to compute the size of the buffer required. 66 * 67 * Returns a negative error number on failure, or the number of bytes 68 * used / required on success. 69 */ 70 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 71 void *buffer, size_t buffer_size) 72 { 73 struct p9_fid *fid; 74 75 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n", 76 name, buffer_size); 77 fid = v9fs_fid_lookup(dentry); 78 if (IS_ERR(fid)) 79 return PTR_ERR(fid); 80 81 return v9fs_fid_xattr_get(fid, name, buffer, buffer_size); 82 } 83 84 /* 85 * v9fs_xattr_set() 86 * 87 * Create, replace or remove an extended attribute for this inode. Buffer 88 * is NULL to remove an existing extended attribute, and non-NULL to 89 * either replace an existing extended attribute, or create a new extended 90 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 91 * specify that an extended attribute must exist and must not exist 92 * previous to the call, respectively. 93 * 94 * Returns 0, or a negative error number on failure. 95 */ 96 int v9fs_xattr_set(struct dentry *dentry, const char *name, 97 const void *value, size_t value_len, int flags) 98 { 99 struct p9_fid *fid = v9fs_fid_lookup(dentry); 100 if (IS_ERR(fid)) 101 return PTR_ERR(fid); 102 return v9fs_fid_xattr_set(fid, name, value, value_len, flags); 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; 111 112 iov_iter_kvec(&from, WRITE | ITER_KVEC, &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 = p9_client_walk(fid, 0, NULL, 1); 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 p9_client_clunk(fid); 132 return retval; 133 } 134 135 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 136 { 137 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size); 138 } 139 140 static int v9fs_xattr_handler_get(const struct xattr_handler *handler, 141 struct dentry *dentry, struct inode *inode, 142 const char *name, void *buffer, size_t size) 143 { 144 const char *full_name = xattr_full_name(handler, name); 145 146 return v9fs_xattr_get(dentry, full_name, buffer, size); 147 } 148 149 static int v9fs_xattr_handler_set(const struct xattr_handler *handler, 150 struct dentry *dentry, struct inode *inode, 151 const char *name, const void *value, 152 size_t size, int flags) 153 { 154 const char *full_name = xattr_full_name(handler, name); 155 156 return v9fs_xattr_set(dentry, full_name, value, size, flags); 157 } 158 159 static struct xattr_handler v9fs_xattr_user_handler = { 160 .prefix = XATTR_USER_PREFIX, 161 .get = v9fs_xattr_handler_get, 162 .set = v9fs_xattr_handler_set, 163 }; 164 165 static struct xattr_handler v9fs_xattr_trusted_handler = { 166 .prefix = XATTR_TRUSTED_PREFIX, 167 .get = v9fs_xattr_handler_get, 168 .set = v9fs_xattr_handler_set, 169 }; 170 171 #ifdef CONFIG_9P_FS_SECURITY 172 static struct xattr_handler v9fs_xattr_security_handler = { 173 .prefix = XATTR_SECURITY_PREFIX, 174 .get = v9fs_xattr_handler_get, 175 .set = v9fs_xattr_handler_set, 176 }; 177 #endif 178 179 const struct xattr_handler *v9fs_xattr_handlers[] = { 180 &v9fs_xattr_user_handler, 181 &v9fs_xattr_trusted_handler, 182 #ifdef CONFIG_9P_FS_POSIX_ACL 183 &v9fs_xattr_acl_access_handler, 184 &v9fs_xattr_acl_default_handler, 185 #endif 186 #ifdef CONFIG_9P_FS_SECURITY 187 &v9fs_xattr_security_handler, 188 #endif 189 NULL 190 }; 191