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 (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22/* 23 * Copyright 2008 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 .file "%M%" 30/* 31 * The strlcpy() function copies at most dstsize-1 characters 32 * (dstsize being the size of the string buffer dst) from src 33 * to dst, truncating src if necessary. The result is always 34 * null-terminated. The function returns strlen(src). Buffer 35 * overflow can be checked as follows: 36 * 37 * if (strlcpy(dst, src, dstsize) >= dstsize) 38 * return -1; 39 */ 40 41#include <sys/asm_linkage.h> 42 43 ! strlcpy implementation is similar to that of strcpy, except 44 ! in this case, the maximum size of the detination must be 45 ! tracked since it bounds our maximum copy size. However, 46 ! we must still continue to check for zero since the routine 47 ! is expected to null-terminate any string that is within 48 ! the dest size bound. 49 ! 50 ! this method starts by checking for and arranging source alignment. 51 ! Once this has occurred, we copy based upon destination alignment. 52 ! This is either by word, halfword, or byte. As this occurs, we 53 ! check for a zero-byte. If one is found, we branch to a method 54 ! which checks for the exact location of a zero-byte within a 55 ! larger word/half-word quantity. 56 57 ENTRY(strlcpy) 58 59 .align 32 60 save %sp, -SA(WINDOWSIZE), %sp 61 subcc %g0, %i2, %g4 ! n = -n or n == 0 ? 62 bz,pn %icc, .getstrlen ! if 0 do nothing but strlen(src) 63 add %i1, %i2, %i3 ! i3 = src + n 64 andcc %i1, 3, %i4 ! word aligned? 65 bz,pn %icc, .wordaligned 66 add %i0, %i2, %i2 ! n = dst + n 67 sub %i4, 4, %i4 ! bytes until src aligned 68 69.alignsrc: 70 ldub [%i3 + %g4], %l1 ! l1 = src[] 71 andcc %l1, 0xff, %g0 ! null byte reached? 72 stub %l1, [%i2 + %g4] ! dst[] = src[] 73 bz,a %icc, .done 74 add %i2, %g4, %i2 ! get single dest ptr for strlen 75 addcc %g4, 1, %g4 ! src++ dest++ n-- 76 bz,pn %icc, .forcenullunalign ! n == 0, append null byte 77 addcc %i4, 1, %i4 ! incr, check align 78 bnz,a %icc, .alignsrc 79 nop 80 81.wordaligned: 82 sethi %hi(0x01010101), %i4 83 add %i2, %g4, %l0 ! l0 = dest 84 or %i4, %lo(0x01010101), %i4 85 sub %i2, 4, %i2 ! pre-incr for in cpy loop 86 andcc %l0, 3, %g1 ! word aligned? 87 bnz %icc, .dstnotaligned 88 sll %i4, 7, %i5 ! Mycroft part deux 89 90.storeword: 91 ld [%i3 + %g4], %l1 ! l1 = src[] 92 addcc %g4, 4, %g4 ! n += 4, src += 4, dst +=4 93 bcs,pn %icc, .lastword 94 andn %i5, %l1, %g1 ! ~word & 0x80808080 95 sub %l1, %i4, %l0 ! word - 0x01010101 96 andcc %l0, %g1, %g0 ! doit 97 bz,a,pt %icc, .storeword ! if expr == 0, no zero byte 98 st %l1, [%i2 + %g4] ! dst[] = src[] 99 100.zerobyte: 101 add %i2, %g4, %i2 ! ptr to dest 102 srl %l1, 24, %g1 ! 1st byte 103 andcc %g1, 0xff, %g0 ! test for end 104 bz,pn %icc, .done 105 stb %g1, [%i2] ! store byte 106 add %i2, 1, %i2 ! dst ++ 107 srl %l1, 16, %g1 ! 2nd byte 108 andcc %g1, 0xff, %g0 ! zero byte ? 109 bz,pn %icc, .done 110 stb %g1, [%i2] ! store byte 111 add %i2, 1, %i2 ! dst ++ 112 srl %l1, 8, %g1 ! 3rd byte 113 andcc %g1, 0xff, %g0 ! zero byte ? 114 bz,pn %icc, .done 115 stb %g1, [%i2] ! store byte 116 stb %l1, [%i2 + 1] ! store last byte 117 add %i2, 1, %i2 ! dst ++ 118 119.done: 120 sub %i2, %i0, %i0 ! len = dst - orig dst 121 ret 122 restore %i0, %g0, %o0 123 124.lastword: 125 add %i2, %g4, %i2 126 sub %g4, 4, %g4 ! undo pre-incr 127 add %i3, %g4, %i3 128 129 srl %l1, 24, %g1 ! 1st byte 130 andcc %g1, 0xff, %g0 ! zero byte? 131 bz,pn %icc, .done 132 stb %g1, [%i2] ! store byte 133 inccc %g4 ! n-- 134 bz .forcenull 135 srl %l1, 16, %g1 ! 2nd byte 136 add %i2, 1, %i2 ! dst++ 137 andcc %g1, 0xff, %g0 ! zero? 138 bz,pn %icc, .done 139 stb %g1, [%i2] ! store 140 inccc %g4 141 bz .forcenull 142 srl %l1, 8, %g1 ! 3rd byte 143 add %i2, 1, %i2 ! dst++ 144 andcc %g1, 0xff, %g0 ! zero? 145 bz,pn %icc, .done 146 stb %g1, [%i2] ! store 147 inccc %g4 ! n-- 148 bz .forcenull 149 andcc %l1, 0xff, %g0 ! zero? 150 add %i2, 1, %i2 ! dst++ 151 bz,pn %ncc, .done 152 stb %l1, [%i2] 153 154.forcenull: 155 stb %g0, [%i2] 156 157.searchword: 158 ld [%i3], %l1 159.searchword2: 160 andn %i5, %l1, %g1 ! word & 0x80808080 161 sub %l1, %i4, %l0 ! word - 0x01010101 162 andcc %l0, %g1, %g0 ! do it 163 bz,a,pt %icc, .searchword 164 add %i3, 4, %i3 ! src += 4 165 166 mov 0xff, %i5 167 sll %i5, 24, %i5 ! mask 1st byte = 0xff000000 168.searchbyte: 169 andcc %l1, %i5, %g0 ! cur byte 0? 170 srl %i5, 8, %i5 ! mask next byte 171 bnz,a %icc, .searchbyte ! cur !=0 continue 172 add %i3, 1, %i3 173 174.endfound: 175 sub %i3, %i1, %i0 ! len = src - orig src 176 ret 177 restore %i0, %g0, %o0 178 nop 179 180.dstnotaligned: 181 cmp %g1, 2 ! halfword aligned? 182 be .storehalfword2 183 .empty 184.storebyte: 185 ld [%i3 + %g4], %l1 ! load src word 186 addcc %g4, 4, %g4 ! src +=4 dst +=4 187 bcs,pn %icc, .lastword 188 andn %i5, %l1, %g1 ! ~x & 0x80808080 189 sub %l1, %i4, %l0 ! x - 0x01010101 190 andcc %l0, %g1, %g0 ! get your Mycroft on 191 bnz,pn %icc, .zerobyte ! non-zero, we have zero byte 192 add %i2, %g4, %l0 ! dst in ptr form 193 srl %l1, 24, %g1 ! get 1st byte, then be hw aligned 194 stb %g1, [%l0] 195 srl %l1, 8, %g1 ! 2nd & 3rd bytes 196 sth %g1, [%l0 + 1] 197 ba .storebyte 198 stb %l1, [%l0 + 3] ! store 4th byte 199 200.storehalfword: 201 ld [%i3 + %g4], %l1 ! src word 202.storehalfword2: 203 addcc %g4, 4, %g4 ! src += 4 dst += 4 204 bcs,pn %icc, .lastword 205 andn %i5, %l1, %g1 ! ~x & 0x80808080 206 sub %l1, %i4, %l0 ! x - 0x01010101 207 andcc %l0, %g1, %g0 ! Mycroft again... 208 bnz,pn %icc, .zerobyte ! non-zer, we have zero byte 209 add %i2, %g4, %l0 ! dst in ptr form 210 srl %l1, 16, %g1 ! first two bytes 211 sth %g1, [%l0] 212 ba .storehalfword 213 sth %l1, [%l0 + 2] 214 215.forcenullunalign: 216 add %i2, %g4, %i2 ! single dst ptr 217 stb %g0, [%i2 - 1] ! store terminating null byte 218 219.getstrlen: 220 sethi %hi(0x01010101), %i4 ! Mycroft... 221 or %i4, %lo(0x01010101), %i4 222 sll %i4, 7, %i5 223 224.getstrlenloop: 225 andcc %i3, 3, %g0 ! word aligned? 226 bz,a,pn %icc, .searchword2 ! search word at a time 227 ld [%i3], %l1 ! src word 228 ldub [%i3], %l1 ! src byte 229 andcc %l1, 0xff, %g0 ! end of src? 230 bnz,a %icc, .getstrlenloop 231 add %i3, 1, %i3 ! src ++ 232 sub %i3, %i1, %i0 ! len = src - orig src 233 ret 234 restore %i0, %g0, %o0 235 SET_SIZE(strlcpy) 236