1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (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 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* 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.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#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/uio.h>
#include <sys/debug.h>
/*
* Read the contents of a symbolic link.
*/
ssize_t
readlink(char *name, char *buf, size_t count)
{
vnode_t *vp;
struct iovec aiov;
struct uio auio;
int error;
struct vattr vattr;
ssize_t cnt;
if ((cnt = (ssize_t)count) < 0)
return (set_errno(EINVAL));
lookup:
if (error = lookupname(name, UIO_USERSPACE, NO_FOLLOW, NULLVPP, &vp)) {
if (error == ESTALE)
goto lookup;
return (set_errno(error));
}
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());
if (error || vattr.va_type != VLNK) {
VN_RELE(vp);
if (error == ESTALE)
goto lookup;
return (set_errno(EINVAL));
}
}
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());
VN_RELE(vp);
if (error) {
if (error == ESTALE)
goto lookup;
return (set_errno(error));
}
return ((ssize_t)(cnt - auio.uio_resid));
}
#ifdef _SYSCALL32_IMPL
/*
* readlink32() intentionally returns a ssize_t rather than ssize32_t;
* see the comments above read32 for details.
*/
ssize_t
readlink32(caddr32_t name, caddr32_t buf, size32_t count)
{
return ((ssize32_t)readlink((char *)(uintptr_t)name,
(char *)(uintptr_t)buf, (ssize32_t)count));
}
#endif /* _SYSCALL32_IMPL */
|
