diff options
Diffstat (limited to 'fs/9p/xattr.c')
| -rw-r--r-- | fs/9p/xattr.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c new file mode 100644 index 000000000..3c4572ef3 --- /dev/null +++ b/fs/9p/xattr.c @@ -0,0 +1,193 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright IBM Corporation, 2010 + * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/sched.h> +#include <linux/uio.h> +#include <linux/posix_acl_xattr.h> +#include <net/9p/9p.h> +#include <net/9p/client.h> + +#include "fid.h" +#include "xattr.h" + +ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, + void *buffer, size_t buffer_size) +{ + ssize_t retval; + u64 attr_size; + struct p9_fid *attr_fid; + struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size}; + struct iov_iter to; + int err; + + iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size); + + attr_fid = p9_client_xattrwalk(fid, name, &attr_size); + if (IS_ERR(attr_fid)) { + retval = PTR_ERR(attr_fid); + p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", + retval); + return retval; + } + if (attr_size > buffer_size) { + if (buffer_size) + retval = -ERANGE; + else if (attr_size > SSIZE_MAX) + retval = -EOVERFLOW; + else /* request to get the attr_size */ + retval = attr_size; + } else { + iov_iter_truncate(&to, attr_size); + retval = p9_client_read(attr_fid, 0, &to, &err); + if (err) + retval = err; + } + p9_fid_put(attr_fid); + return retval; +} + + +/* + * v9fs_xattr_get() + * + * Copy an extended attribute into the buffer + * provided, or compute the buffer size required. + * Buffer is NULL to compute the size of the buffer required. + * + * Returns a negative error number on failure, or the number of bytes + * used / required on success. + */ +ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, + void *buffer, size_t buffer_size) +{ + struct p9_fid *fid; + int ret; + + p9_debug(P9_DEBUG_VFS, "name = '%s' value_len = %zu\n", + name, buffer_size); + fid = v9fs_fid_lookup(dentry); + if (IS_ERR(fid)) + return PTR_ERR(fid); + ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size); + p9_fid_put(fid); + + return ret; +} + +/* + * v9fs_xattr_set() + * + * Create, replace or remove an extended attribute for this inode. Buffer + * is NULL to remove an existing extended attribute, and non-NULL to + * either replace an existing extended attribute, or create a new extended + * attribute. The flags XATTR_REPLACE and XATTR_CREATE + * specify that an extended attribute must exist and must not exist + * previous to the call, respectively. + * + * Returns 0, or a negative error number on failure. + */ +int v9fs_xattr_set(struct dentry *dentry, const char *name, + const void *value, size_t value_len, int flags) +{ + int ret; + struct p9_fid *fid; + + fid = v9fs_fid_lookup(dentry); + if (IS_ERR(fid)) + return PTR_ERR(fid); + ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags); + p9_fid_put(fid); + return ret; +} + +int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name, + const void *value, size_t value_len, int flags) +{ + struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len}; + struct iov_iter from; + int retval, err; + + iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len); + + p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n", + name, value_len, flags); + + /* Clone it */ + fid = clone_fid(fid); + if (IS_ERR(fid)) + return PTR_ERR(fid); + + /* + * On success fid points to xattr + */ + retval = p9_client_xattrcreate(fid, name, value_len, flags); + if (retval < 0) + p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n", + retval); + else + p9_client_write(fid, 0, &from, &retval); + err = p9_fid_put(fid); + if (!retval && err) + retval = err; + return retval; +} + +ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) +{ + /* Txattrwalk with an empty string lists xattrs instead */ + return v9fs_xattr_get(dentry, "", buffer, buffer_size); +} + +static int v9fs_xattr_handler_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + const char *full_name = xattr_full_name(handler, name); + + return v9fs_xattr_get(dentry, full_name, buffer, size); +} + +static int v9fs_xattr_handler_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + const char *full_name = xattr_full_name(handler, name); + + return v9fs_xattr_set(dentry, full_name, value, size, flags); +} + +static struct xattr_handler v9fs_xattr_user_handler = { + .prefix = XATTR_USER_PREFIX, + .get = v9fs_xattr_handler_get, + .set = v9fs_xattr_handler_set, +}; + +static struct xattr_handler v9fs_xattr_trusted_handler = { + .prefix = XATTR_TRUSTED_PREFIX, + .get = v9fs_xattr_handler_get, + .set = v9fs_xattr_handler_set, +}; + +#ifdef CONFIG_9P_FS_SECURITY +static struct xattr_handler v9fs_xattr_security_handler = { + .prefix = XATTR_SECURITY_PREFIX, + .get = v9fs_xattr_handler_get, + .set = v9fs_xattr_handler_set, +}; +#endif + +const struct xattr_handler *v9fs_xattr_handlers[] = { + &v9fs_xattr_user_handler, + &v9fs_xattr_trusted_handler, +#ifdef CONFIG_9P_FS_SECURITY + &v9fs_xattr_security_handler, +#endif + NULL +}; |