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 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 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 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