libcmdutils/common/sysattrs.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h>
#include <attr.h>
#include <fcntl.h>
#include <errno.h>
#include "libcmdutils.h"

/*
 * Returns the status of attempting to obtain the extended system
 * attributes in the specified view.
 *
 * Note: If obtaining status for an extended attribute file, the caller must
 * chdir into the hidden directory prior to calling sysattr_status().
 *
 * Returns 1 if the extended system attributes were obtained, otherwise
 * returns 0.
 */
int
sysattr_status(char *file, xattr_view_t view)
{
    nvlist_t    *response = NULL;
    int     saveerrno;
    int     status;

    status = getattrat(AT_FDCWD, view, file, &response);

    saveerrno = errno;
    if (response)
        (void) nvlist_free(response);
    errno = saveerrno;

    return (status == 0);
}

/*
 * Returns the type of the specified in file.  If the file name matches
 * the name of either a read-only or read-write extended system attribute
 * file then sysattr_type() returns the type of file:
 *  return value    file type
 *  ------------    ---------
 *  _RO_SATTR   read-only extended system attribute file
 *  _RW_SATTR   read-write extended system attribute file
 *  _NOT_SATTR  neither a read-only or read-write extended system
 *          attribute file.
 */
int
sysattr_type(char *file)
{
    if (file == NULL) {
        errno = ENOENT;
        return (_NOT_SATTR);
    }

    if (strcmp(basename(file), file) != 0) {
        errno = EINVAL;
        return (_NOT_SATTR);
    }

    errno = 0;
    if (strcmp(file, VIEW_READONLY) == 0) {
        return (_RO_SATTR);
    } else if (strcmp(file, VIEW_READWRITE) == 0) {
        return (_RW_SATTR);
    } else {
        return (_NOT_SATTR);
    }
}

/*
 * Call sysattr_support() instead of pathconf(file, _PC_SATTR_ENABLED) or
 * pathconf(file, _PC_SATTR_EXISTS) so that if pathconf() fails over NFS, we
 * can still try to figure out if extended system attributes are supported by
 * testing for a valid extended system attribute file.
 *
 * 'name' can have the values _PC_SATTR_ENABLED or _PC_SATTR_EXISTS.
 *
 * Returns 1 if the underlying file system supports extended system attributes,
 * otherwise, returns -1.
 */
int
sysattr_support(char *file, int name)
{
    int rc;

    errno = 0;
    if ((name != _PC_SATTR_ENABLED) &&
        (name != _PC_SATTR_EXISTS)) {
        errno = EINVAL;
        return (-1);
    }
    if (((rc = pathconf(file, name)) == 1) || (errno != EINVAL)) {
        return (rc);
    }
    return (sysattr_status(file, XATTR_VIEW_READONLY));
}