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1// SPDX-License-Identifier: LGPL-2.12/*3 * Copyright IBM Corporation, 20104 * 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 18ssize_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)39 retval = -ERANGE;40 else if (attr_size > SSIZE_MAX)41 retval = -EOVERFLOW;42 else /* request to get the attr_size */43 retval = attr_size;44 } else {45 iov_iter_truncate(&to, attr_size);46 retval = p9_client_read(attr_fid, 0, &to, &err);47 if (err)48 retval = err;49 }50 p9_fid_put(attr_fid);51 return retval;52}53 54 55/*56 * v9fs_xattr_get()57 *58 * Copy an extended attribute into the buffer59 * provided, or compute the buffer size required.60 * Buffer is NULL to compute the size of the buffer required.61 *62 * Returns a negative error number on failure, or the number of bytes63 * used / required on success.64 */65ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,66 void *buffer, size_t buffer_size)67{68 struct p9_fid *fid;69 int ret;70 71 p9_debug(P9_DEBUG_VFS, "name = '%s' value_len = %zu\n",72 name, buffer_size);73 fid = v9fs_fid_lookup(dentry);74 if (IS_ERR(fid))75 return PTR_ERR(fid);76 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);77 p9_fid_put(fid);78 79 return ret;80}81 82/*83 * v9fs_xattr_set()84 *85 * Create, replace or remove an extended attribute for this inode. Buffer86 * is NULL to remove an existing extended attribute, and non-NULL to87 * either replace an existing extended attribute, or create a new extended88 * attribute. The flags XATTR_REPLACE and XATTR_CREATE89 * specify that an extended attribute must exist and must not exist90 * previous to the call, respectively.91 *92 * Returns 0, or a negative error number on failure.93 */94int v9fs_xattr_set(struct dentry *dentry, const char *name,95 const void *value, size_t value_len, int flags)96{97 int ret;98 struct p9_fid *fid;99 100 fid = v9fs_fid_lookup(dentry);101 if (IS_ERR(fid))102 return PTR_ERR(fid);103 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);104 p9_fid_put(fid);105 return ret;106}107 108int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,109 const void *value, size_t value_len, int flags)110{111 struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};112 struct iov_iter from;113 int retval, err;114 115 iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len);116 117 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",118 name, value_len, flags);119 120 /* Clone it */121 fid = clone_fid(fid);122 if (IS_ERR(fid))123 return PTR_ERR(fid);124 125 /*126 * On success fid points to xattr127 */128 retval = p9_client_xattrcreate(fid, name, value_len, flags);129 if (retval < 0)130 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",131 retval);132 else133 p9_client_write(fid, 0, &from, &retval);134 err = p9_fid_put(fid);135 if (!retval && err)136 retval = err;137 return retval;138}139 140ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)141{142 /* Txattrwalk with an empty string lists xattrs instead */143 return v9fs_xattr_get(dentry, "", buffer, buffer_size);144}145 146static int v9fs_xattr_handler_get(const struct xattr_handler *handler,147 struct dentry *dentry, struct inode *inode,148 const char *name, void *buffer, size_t size)149{150 const char *full_name = xattr_full_name(handler, name);151 152 return v9fs_xattr_get(dentry, full_name, buffer, size);153}154 155static int v9fs_xattr_handler_set(const struct xattr_handler *handler,156 struct mnt_idmap *idmap,157 struct dentry *dentry, struct inode *inode,158 const char *name, const void *value,159 size_t size, int flags)160{161 const char *full_name = xattr_full_name(handler, name);162 163 return v9fs_xattr_set(dentry, full_name, value, size, flags);164}165 166static const struct xattr_handler v9fs_xattr_user_handler = {167 .prefix = XATTR_USER_PREFIX,168 .get = v9fs_xattr_handler_get,169 .set = v9fs_xattr_handler_set,170};171 172static const struct xattr_handler v9fs_xattr_trusted_handler = {173 .prefix = XATTR_TRUSTED_PREFIX,174 .get = v9fs_xattr_handler_get,175 .set = v9fs_xattr_handler_set,176};177 178#ifdef CONFIG_9P_FS_SECURITY179static const struct xattr_handler v9fs_xattr_security_handler = {180 .prefix = XATTR_SECURITY_PREFIX,181 .get = v9fs_xattr_handler_get,182 .set = v9fs_xattr_handler_set,183};184#endif185 186const struct xattr_handler * const v9fs_xattr_handlers[] = {187 &v9fs_xattr_user_handler,188 &v9fs_xattr_trusted_handler,189#ifdef CONFIG_9P_FS_SECURITY190 &v9fs_xattr_security_handler,191#endif192 NULL193};194