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/*
* 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/cred.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/pathname.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#include <sys/debug.h>
#include <fs/fs_subr.h>
#include <c2/audit.h>
/*
* Read the contents of a symbolic link.
*/
ssize_t
readlinkat(int dfd, char *name, char *buf, size_t count)
{
vnode_t *startvp;
vnode_t *vp;
struct iovec aiov;
struct uio auio;
int error;
struct vattr vattr;
ssize_t cnt;
int estale_retry = 0;
if ((cnt = (ssize_t)count) < 0)
return (set_errno(EINVAL));
if (name == NULL)
return (set_errno(EFAULT));
if ((error = fgetstartvp(dfd, name, &startvp)) != 0)
return (set_errno(error));
lookup:
if (AU_AUDITING() && startvp != NULL)
audit_setfsat_path(1);
if (error = lookupnameat(name, UIO_USERSPACE, NO_FOLLOW,
NULLVPP, &vp, startvp)) {
if (error == ESTALE && fs_need_estale_retry(estale_retry++))
goto lookup;
goto out;
}
if (vp->v_type != VLNK) {
/*
* Ask the underlying filesystem if it wants this
* object to look like a symlink at user-level.
*/
vattr.va_mask = AT_TYPE;
error = VOP_GETATTR(vp, &vattr, 0, CRED(), NULL);
if (error || vattr.va_type != VLNK) {
VN_RELE(vp);
if ((error == ESTALE) &&
fs_need_estale_retry(estale_retry++))
goto lookup;
error = EINVAL;
goto out;
}
}
aiov.iov_base = buf;
aiov.iov_len = cnt;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_loffset = 0;
auio.uio_segflg = UIO_USERSPACE;
auio.uio_extflg = UIO_COPY_CACHED;
auio.uio_resid = cnt;
error = VOP_READLINK(vp, &auio, CRED(), NULL);
VN_RELE(vp);
if (error == ESTALE && fs_need_estale_retry(estale_retry++))
goto lookup;
out:
if (startvp != NULL)
VN_RELE(startvp);
if (error)
return (set_errno(error));
return ((ssize_t)(cnt - auio.uio_resid));
}
ssize_t
readlink(char *name, char *buf, size_t count)
{
return (readlinkat(AT_FDCWD, name, buf, count));
}
#ifdef _SYSCALL32_IMPL
/*
* readlink32() intentionally returns a ssize_t rather than ssize32_t;
* see the comments above read32 for details.
*/
ssize_t
readlinkat32(int dfd, caddr32_t name, caddr32_t buf, size32_t count)
{
return ((ssize32_t)readlinkat(dfd, (char *)(uintptr_t)name,
(char *)(uintptr_t)buf, (ssize32_t)count));
}
ssize_t
readlink32(caddr32_t name, caddr32_t buf, size32_t count)
{
return ((ssize32_t)readlinkat(AT_FDCWD, (char *)(uintptr_t)name,
(char *)(uintptr_t)buf, (ssize32_t)count));
}
#endif /* _SYSCALL32_IMPL */
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