/*
 * 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 (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
/*        All Rights Reserved   */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

#include <sys/param.h>
#include <sys/isa_defs.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/pathname.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/debug.h>
#include <c2/audit.h>
#include <fs/fs_subr.h>

/*
 * Create a symbolic link.  Similar to link or rename except target
 * name is passed as string argument, not converted to vnode reference.
 */
int
symlinkat(char *target, int dfd, char *linkname)
{
        vnode_t *startvp;
        vnode_t *dvp;
        struct vattr vattr;
        struct pathname lpn;
        char *tbuf;
        size_t tlen;
        int error;
        int estale_retry = 0;
        int auditing = AU_AUDITING();

        if (linkname == NULL)
                return (set_errno(EFAULT));
        if ((error = fgetstartvp(dfd, linkname, &startvp)) != 0)
                return (set_errno(error));

top:
        if (error = pn_get(linkname, UIO_USERSPACE, &lpn))
                goto out;
        if (auditing && startvp != NULL)
                audit_setfsat_path(2);
        if (error = lookuppnat(&lpn, NULL, NO_FOLLOW, &dvp, NULLVPP, startvp)) {
                pn_free(&lpn);
                if (error == ESTALE && fs_need_estale_retry(estale_retry++))
                        goto top;
                goto out;
        }
        if (vn_is_readonly(dvp))
                error = EROFS;
        else if (pn_fixslash(&lpn))
                error = ENOTDIR;
        else {
                tbuf = kmem_alloc(MAXPATHLEN, KM_SLEEP);
                if ((error = copyinstr(target, tbuf, MAXPATHLEN, &tlen)) == 0) {
                        vattr.va_type = VLNK;
                        vattr.va_mode = 0777;
                        vattr.va_mask = AT_TYPE|AT_MODE;
                        error = VOP_SYMLINK(dvp, lpn.pn_path, &vattr,
                            tbuf, CRED(), NULL, 0);
                        if (auditing)
                                audit_symlink_create(dvp, lpn.pn_path,
                                    tbuf, error);
                }
                kmem_free(tbuf, MAXPATHLEN);
        }
        pn_free(&lpn);
        VN_RELE(dvp);
        if (error == ESTALE && fs_need_estale_retry(estale_retry++))
                goto top;
out:
        if (startvp != NULL)
                VN_RELE(startvp);
        if (error)
                return (set_errno(error));
        return (0);
}

int
symlink(char *target, char *linkname)
{
        return (symlinkat(target, AT_FDCWD, linkname));
}