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 .file "strlcpy.s" 28/* 29 * The strlcpy() function copies at most dstsize-1 characters 30 * (dstsize being the size of the string buffer dst) from src 31 * to dst, truncating src if necessary. The result is always 32 * null-terminated. The function returns strlen(src). Buffer 33 * overflow can be checked as follows: 34 * 35 * if (strlcpy(dst, src, dstsize) >= dstsize) 36 * return -1; 37 */ 38 39#include <sys/asm_linkage.h> 40 41 ! strlcpy implementation is similar to that of strcpy, except 42 ! in this case, the maximum size of the detination must be 43 ! tracked since it bounds our maximum copy size. However, 44 ! we must still continue to check for zero since the routine 45 ! is expected to null-terminate any string that is within 46 ! the dest size bound. 47 ! 48 ! this method starts by checking for and arranging source alignment. 49 ! Once this has occurred, we copy based upon destination alignment. 50 ! This is either by word, halfword, or byte. As this occurs, we 51 ! check for a zero-byte. If one is found, we branch to a method 52 ! which checks for the exact location of a zero-byte within a 53 ! larger word/half-word quantity. 54 55 ENTRY(strlcpy) 56 57 .align 32 58 save %sp, -SA(WINDOWSIZE), %sp 59 subcc %g0, %i2, %g4 ! n = -n or n == 0 ? 60 bz,pn %icc, .getstrlen ! if 0 do nothing but strlen(src) 61 add %i1, %i2, %i3 ! i3 = src + n 62 andcc %i1, 3, %i4 ! word aligned? 63 bz,pn %icc, .wordaligned 64 add %i0, %i2, %i2 ! n = dst + n 65 sub %i4, 4, %i4 ! bytes until src aligned 66 67.alignsrc: 68 ldub [%i3 + %g4], %l1 ! l1 = src[] 69 andcc %l1, 0xff, %g0 ! null byte reached? 70 stub %l1, [%i2 + %g4] ! dst[] = src[] 71 bz,a %icc, .done 72 add %i2, %g4, %i2 ! get single dest ptr for strlen 73 addcc %g4, 1, %g4 ! src++ dest++ n-- 74 bz,pn %icc, .forcenullunalign ! n == 0, append null byte 75 addcc %i4, 1, %i4 ! incr, check align 76 bnz,a %icc, .alignsrc 77 nop 78 79.wordaligned: 80 sethi %hi(0x01010101), %i4 81 add %i2, %g4, %l0 ! l0 = dest 82 or %i4, %lo(0x01010101), %i4 83 sub %i2, 4, %i2 ! pre-incr for in cpy loop 84 andcc %l0, 3, %g1 ! word aligned? 85 bnz %icc, .dstnotaligned 86 sll %i4, 7, %i5 ! Mycroft part deux 87 88.storeword: 89 ld [%i3 + %g4], %l1 ! l1 = src[] 90 addcc %g4, 4, %g4 ! n += 4, src += 4, dst +=4 91 bcs,pn %icc, .lastword 92 andn %i5, %l1, %g1 ! ~word & 0x80808080 93 sub %l1, %i4, %l0 ! word - 0x01010101 94 andcc %l0, %g1, %g0 ! doit 95 bz,a,pt %icc, .storeword ! if expr == 0, no zero byte 96 st %l1, [%i2 + %g4] ! dst[] = src[] 97 98.zerobyte: 99 add %i2, %g4, %i2 ! ptr to dest 100 srl %l1, 24, %g1 ! 1st byte 101 andcc %g1, 0xff, %g0 ! test for end 102 bz,pn %icc, .done 103 stb %g1, [%i2] ! store byte 104 add %i2, 1, %i2 ! dst ++ 105 srl %l1, 16, %g1 ! 2nd byte 106 andcc %g1, 0xff, %g0 ! zero byte ? 107 bz,pn %icc, .done 108 stb %g1, [%i2] ! store byte 109 add %i2, 1, %i2 ! dst ++ 110 srl %l1, 8, %g1 ! 3rd byte 111 andcc %g1, 0xff, %g0 ! zero byte ? 112 bz,pn %icc, .done 113 stb %g1, [%i2] ! store byte 114 stb %l1, [%i2 + 1] ! store last byte 115 add %i2, 1, %i2 ! dst ++ 116 117.done: 118 sub %i2, %i0, %i0 ! len = dst - orig dst 119 ret 120 restore %i0, %g0, %o0 121 122.lastword: 123 add %i2, %g4, %i2 124 sub %g4, 4, %g4 ! undo pre-incr 125 add %i3, %g4, %i3 126 127 srl %l1, 24, %g1 ! 1st byte 128 andcc %g1, 0xff, %g0 ! zero byte? 129 bz,pn %icc, .done 130 stb %g1, [%i2] ! store byte 131 inccc %g4 ! n-- 132 bz .forcenull 133 srl %l1, 16, %g1 ! 2nd byte 134 add %i2, 1, %i2 ! dst++ 135 andcc %g1, 0xff, %g0 ! zero? 136 bz,pn %icc, .done 137 stb %g1, [%i2] ! store 138 inccc %g4 139 bz .forcenull 140 srl %l1, 8, %g1 ! 3rd byte 141 add %i2, 1, %i2 ! dst++ 142 andcc %g1, 0xff, %g0 ! zero? 143 bz,pn %icc, .done 144 stb %g1, [%i2] ! store 145 inccc %g4 ! n-- 146 bz .forcenull 147 andcc %l1, 0xff, %g0 ! zero? 148 add %i2, 1, %i2 ! dst++ 149 bz,pn %ncc, .done 150 stb %l1, [%i2] 151 152.forcenull: 153 stb %g0, [%i2] 154 155.searchword: 156 ld [%i3], %l1 157.searchword2: 158 andn %i5, %l1, %g1 ! word & 0x80808080 159 sub %l1, %i4, %l0 ! word - 0x01010101 160 andcc %l0, %g1, %g0 ! do it 161 bz,a,pt %icc, .searchword 162 add %i3, 4, %i3 ! src += 4 163 164 mov 0xff, %i5 165 sll %i5, 24, %i5 ! mask 1st byte = 0xff000000 166.searchbyte: 167 andcc %l1, %i5, %g0 ! cur byte 0? 168 srl %i5, 8, %i5 ! mask next byte 169 bnz,a %icc, .searchbyte ! cur !=0 continue 170 add %i3, 1, %i3 171 172.endfound: 173 sub %i3, %i1, %i0 ! len = src - orig src 174 ret 175 restore %i0, %g0, %o0 176 nop 177 178.dstnotaligned: 179 cmp %g1, 2 ! halfword aligned? 180 be .storehalfword2 181 .empty 182.storebyte: 183 ld [%i3 + %g4], %l1 ! load src word 184 addcc %g4, 4, %g4 ! src +=4 dst +=4 185 bcs,pn %icc, .lastword 186 andn %i5, %l1, %g1 ! ~x & 0x80808080 187 sub %l1, %i4, %l0 ! x - 0x01010101 188 andcc %l0, %g1, %g0 ! get your Mycroft on 189 bnz,pn %icc, .zerobyte ! non-zero, we have zero byte 190 add %i2, %g4, %l0 ! dst in ptr form 191 srl %l1, 24, %g1 ! get 1st byte, then be hw aligned 192 stb %g1, [%l0] 193 srl %l1, 8, %g1 ! 2nd & 3rd bytes 194 sth %g1, [%l0 + 1] 195 ba .storebyte 196 stb %l1, [%l0 + 3] ! store 4th byte 197 198.storehalfword: 199 ld [%i3 + %g4], %l1 ! src word 200.storehalfword2: 201 addcc %g4, 4, %g4 ! src += 4 dst += 4 202 bcs,pn %icc, .lastword 203 andn %i5, %l1, %g1 ! ~x & 0x80808080 204 sub %l1, %i4, %l0 ! x - 0x01010101 205 andcc %l0, %g1, %g0 ! Mycroft again... 206 bnz,pn %icc, .zerobyte ! non-zer, we have zero byte 207 add %i2, %g4, %l0 ! dst in ptr form 208 srl %l1, 16, %g1 ! first two bytes 209 sth %g1, [%l0] 210 ba .storehalfword 211 sth %l1, [%l0 + 2] 212 213.forcenullunalign: 214 add %i2, %g4, %i2 ! single dst ptr 215 stb %g0, [%i2 - 1] ! store terminating null byte 216 217.getstrlen: 218 sethi %hi(0x01010101), %i4 ! Mycroft... 219 or %i4, %lo(0x01010101), %i4 220 sll %i4, 7, %i5 221 222.getstrlenloop: 223 andcc %i3, 3, %g0 ! word aligned? 224 bz,a,pn %icc, .searchword2 ! search word at a time 225 ld [%i3], %l1 ! src word 226 ldub [%i3], %l1 ! src byte 227 andcc %l1, 0xff, %g0 ! end of src? 228 bnz,a %icc, .getstrlenloop 229 add %i3, 1, %i3 ! src ++ 230 sub %i3, %i1, %i0 ! len = src - orig src 231 ret 232 restore %i0, %g0, %o0 233 SET_SIZE(strlcpy) 234