1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 /*
30 * Miscellaneous C routines for copying data around without
31 * descending into assembler. Compilers are pretty good at
32 * scheduling instructions, and humans are pretty hopeless at
33 * writing correct assembler.
34 */
35
36 #include <sys/types.h>
37 #include <sys/systm.h>
38 #include <sys/errno.h>
39 #include <sys/param.h>
40
41 /*
42 * copyinstr_noerr and copyoutstr_noerr can be implemented completely
43 * in C on machines with shared user and kernel context.
44 */
45 static int
copystr_nofault(const char * src,char * dst,size_t maxlength,size_t * lencopied)46 copystr_nofault(const char *src, char *dst, size_t maxlength,
47 size_t *lencopied)
48 {
49 int error = 0;
50 size_t leftover;
51
52 if ((leftover = maxlength) == 0)
53 error = ENAMETOOLONG;
54 else
55 do {
56 leftover--;
57 if ((*dst++ = *src++) == '\0')
58 break;
59 if (leftover == 0) {
60 error = ENAMETOOLONG;
61 break;
62 }
63 /*CONSTCOND*/
64 } while (1);
65
66 if (lencopied)
67 *lencopied = maxlength - leftover;
68 return (error);
69 }
70
71
72 int
copyinstr_noerr(const char * uaddr,char * kaddr,size_t maxlength,size_t * lencopied)73 copyinstr_noerr(const char *uaddr, char *kaddr, size_t maxlength,
74 size_t *lencopied)
75 {
76 char *ua = (char *)uaddr;
77
78 ASSERT((uintptr_t)kaddr > kernelbase);
79
80 if ((uintptr_t)ua > kernelbase) {
81 /*
82 * force fault at kernelbase
83 */
84 ua = (char *)kernelbase;
85 }
86 return (copystr_nofault(ua, kaddr, maxlength, lencopied));
87 }
88
89 int
copyoutstr_noerr(const char * kaddr,char * uaddr,size_t maxlength,size_t * lencopied)90 copyoutstr_noerr(const char *kaddr, char *uaddr, size_t maxlength,
91 size_t *lencopied)
92 {
93 char *ua = (char *)uaddr;
94
95 ASSERT((uintptr_t)kaddr > kernelbase);
96
97 if ((uintptr_t)ua > kernelbase) {
98 /*
99 * force fault at kernelbase
100 */
101 ua = (char *)kernelbase;
102 }
103 return (copystr_nofault(kaddr, ua, maxlength, lencopied));
104 }
105