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![Andreas Gruenbacher](/assets/img/avatar_default.png)
Now that the xattr handler is passed to the xattr handler operations, we can use the same get and set operations for the user, trusted, and security xattr namespaces. In those namespaces, we can access the full attribute name by "reattaching" the name prefix the vfs has skipped for us. Add a xattr_full_name helper to make this obvious in the code. For the "system.posix_acl_access" and "system.posix_acl_default" attributes, handler->prefix is the full attribute name; the suffix is the empty string. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: v9fs-developer@lists.sourceforge.net Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
193 lines
5.2 KiB
C
193 lines
5.2 KiB
C
/*
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* Copyright IBM Corporation, 2010
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* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2.1 of the GNU Lesser General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/uio.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include "fid.h"
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#include "xattr.h"
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ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
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void *buffer, size_t buffer_size)
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{
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ssize_t retval;
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u64 attr_size;
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struct p9_fid *attr_fid;
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struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
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struct iov_iter to;
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int err;
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iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buffer_size);
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attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
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if (IS_ERR(attr_fid)) {
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retval = PTR_ERR(attr_fid);
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p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
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retval);
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return retval;
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}
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if (attr_size > buffer_size) {
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if (!buffer_size) /* request to get the attr_size */
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retval = attr_size;
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else
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retval = -ERANGE;
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} else {
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iov_iter_truncate(&to, attr_size);
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retval = p9_client_read(attr_fid, 0, &to, &err);
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if (err)
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retval = err;
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}
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p9_client_clunk(attr_fid);
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return retval;
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}
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/*
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* v9fs_xattr_get()
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*
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* Copy an extended attribute into the buffer
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* provided, or compute the buffer size required.
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* Buffer is NULL to compute the size of the buffer required.
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*
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* Returns a negative error number on failure, or the number of bytes
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* used / required on success.
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*/
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ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
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void *buffer, size_t buffer_size)
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{
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struct p9_fid *fid;
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p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n",
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name, buffer_size);
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fid = v9fs_fid_lookup(dentry);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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return v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
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}
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/*
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* v9fs_xattr_set()
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*
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* Create, replace or remove an extended attribute for this inode. Buffer
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* is NULL to remove an existing extended attribute, and non-NULL to
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* either replace an existing extended attribute, or create a new extended
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* attribute. The flags XATTR_REPLACE and XATTR_CREATE
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* specify that an extended attribute must exist and must not exist
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* previous to the call, respectively.
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*
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* Returns 0, or a negative error number on failure.
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*/
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int v9fs_xattr_set(struct dentry *dentry, const char *name,
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const void *value, size_t value_len, int flags)
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{
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struct p9_fid *fid = v9fs_fid_lookup(dentry);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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return v9fs_fid_xattr_set(fid, name, value, value_len, flags);
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}
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int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
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const void *value, size_t value_len, int flags)
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{
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struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
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struct iov_iter from;
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int retval;
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iov_iter_kvec(&from, WRITE | ITER_KVEC, &kvec, 1, value_len);
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p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
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name, value_len, flags);
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/* Clone it */
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fid = p9_client_walk(fid, 0, NULL, 1);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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/*
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* On success fid points to xattr
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*/
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retval = p9_client_xattrcreate(fid, name, value_len, flags);
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if (retval < 0)
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p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
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retval);
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else
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p9_client_write(fid, 0, &from, &retval);
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p9_client_clunk(fid);
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return retval;
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}
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ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
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{
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return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
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}
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static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
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struct dentry *dentry, const char *name,
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void *buffer, size_t size)
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{
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const char *full_name = xattr_full_name(handler, name);
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if (strcmp(name, "") == 0)
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return -EINVAL;
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return v9fs_xattr_get(dentry, full_name, buffer, size);
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}
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static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
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struct dentry *dentry, const char *name,
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const void *value, size_t size, int flags)
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{
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const char *full_name = xattr_full_name(handler, name);
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if (strcmp(name, "") == 0)
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return -EINVAL;
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return v9fs_xattr_set(dentry, full_name, value, size, flags);
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}
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static struct xattr_handler v9fs_xattr_user_handler = {
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.prefix = XATTR_USER_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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static struct xattr_handler v9fs_xattr_trusted_handler = {
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.prefix = XATTR_TRUSTED_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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#ifdef CONFIG_9P_FS_SECURITY
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static struct xattr_handler v9fs_xattr_security_handler = {
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.prefix = XATTR_SECURITY_PREFIX,
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.get = v9fs_xattr_handler_get,
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.set = v9fs_xattr_handler_set,
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};
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#endif
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const struct xattr_handler *v9fs_xattr_handlers[] = {
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&v9fs_xattr_user_handler,
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&v9fs_xattr_trusted_handler,
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#ifdef CONFIG_9P_FS_POSIX_ACL
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&v9fs_xattr_acl_access_handler,
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&v9fs_xattr_acl_default_handler,
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#endif
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#ifdef CONFIG_9P_FS_SECURITY
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&v9fs_xattr_security_handler,
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#endif
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NULL
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};
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