/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (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 2008 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ .file "strlcpy.s" /* * The strlcpy() function copies at most dstsize-1 characters * (dstsize being the size of the string buffer dst) from src * to dst, truncating src if necessary. The result is always * null-terminated. The function returns strlen(src). Buffer * overflow can be checked as follows: * * if (strlcpy(dst, src, dstsize) >= dstsize) * return -1; */ #include ! strlcpy implementation is similar to that of strcpy, except ! in this case, the maximum size of the detination must be ! tracked since it bounds our maximum copy size. However, ! we must still continue to check for zero since the routine ! is expected to null-terminate any string that is within ! the dest size bound. ! ! this method starts by checking for and arranging source alignment. ! Once this has occurred, we copy based upon destination alignment. ! This is either by word, halfword, or byte. As this occurs, we ! check for a zero-byte. If one is found, we branch to a method ! which checks for the exact location of a zero-byte within a ! larger word/half-word quantity. ENTRY(strlcpy) .align 32 save %sp, -SA(WINDOWSIZE), %sp subcc %g0, %i2, %g4 ! n = -n or n == 0 ? bz,pn %icc, .getstrlen ! if 0 do nothing but strlen(src) add %i1, %i2, %i3 ! i3 = src + n andcc %i1, 3, %i4 ! word aligned? bz,pn %icc, .wordaligned add %i0, %i2, %i2 ! n = dst + n sub %i4, 4, %i4 ! bytes until src aligned .alignsrc: ldub [%i3 + %g4], %l1 ! l1 = src[] andcc %l1, 0xff, %g0 ! null byte reached? stub %l1, [%i2 + %g4] ! dst[] = src[] bz,a %icc, .done add %i2, %g4, %i2 ! get single dest ptr for strlen addcc %g4, 1, %g4 ! src++ dest++ n-- bz,pn %icc, .forcenullunalign ! n == 0, append null byte addcc %i4, 1, %i4 ! incr, check align bnz,a %icc, .alignsrc nop .wordaligned: sethi %hi(0x01010101), %i4 add %i2, %g4, %l0 ! l0 = dest or %i4, %lo(0x01010101), %i4 sub %i2, 4, %i2 ! pre-incr for in cpy loop andcc %l0, 3, %g1 ! word aligned? bnz %icc, .dstnotaligned sll %i4, 7, %i5 ! Mycroft part deux .storeword: ld [%i3 + %g4], %l1 ! l1 = src[] addcc %g4, 4, %g4 ! n += 4, src += 4, dst +=4 bcs,pn %icc, .lastword andn %i5, %l1, %g1 ! ~word & 0x80808080 sub %l1, %i4, %l0 ! word - 0x01010101 andcc %l0, %g1, %g0 ! doit bz,a,pt %icc, .storeword ! if expr == 0, no zero byte st %l1, [%i2 + %g4] ! dst[] = src[] .zerobyte: add %i2, %g4, %i2 ! ptr to dest srl %l1, 24, %g1 ! 1st byte andcc %g1, 0xff, %g0 ! test for end bz,pn %icc, .done stb %g1, [%i2] ! store byte add %i2, 1, %i2 ! dst ++ srl %l1, 16, %g1 ! 2nd byte andcc %g1, 0xff, %g0 ! zero byte ? bz,pn %icc, .done stb %g1, [%i2] ! store byte add %i2, 1, %i2 ! dst ++ srl %l1, 8, %g1 ! 3rd byte andcc %g1, 0xff, %g0 ! zero byte ? bz,pn %icc, .done stb %g1, [%i2] ! store byte stb %l1, [%i2 + 1] ! store last byte add %i2, 1, %i2 ! dst ++ .done: sub %i2, %i0, %i0 ! len = dst - orig dst ret restore %i0, %g0, %o0 .lastword: add %i2, %g4, %i2 sub %g4, 4, %g4 ! undo pre-incr add %i3, %g4, %i3 srl %l1, 24, %g1 ! 1st byte andcc %g1, 0xff, %g0 ! zero byte? bz,pn %icc, .done stb %g1, [%i2] ! store byte inccc %g4 ! n-- bz .forcenull srl %l1, 16, %g1 ! 2nd byte add %i2, 1, %i2 ! dst++ andcc %g1, 0xff, %g0 ! zero? bz,pn %icc, .done stb %g1, [%i2] ! store inccc %g4 bz .forcenull srl %l1, 8, %g1 ! 3rd byte add %i2, 1, %i2 ! dst++ andcc %g1, 0xff, %g0 ! zero? bz,pn %icc, .done stb %g1, [%i2] ! store inccc %g4 ! n-- bz .forcenull andcc %l1, 0xff, %g0 ! zero? add %i2, 1, %i2 ! dst++ bz,pn %ncc, .done stb %l1, [%i2] .forcenull: stb %g0, [%i2] .searchword: ld [%i3], %l1 .searchword2: andn %i5, %l1, %g1 ! word & 0x80808080 sub %l1, %i4, %l0 ! word - 0x01010101 andcc %l0, %g1, %g0 ! do it bz,a,pt %icc, .searchword add %i3, 4, %i3 ! src += 4 mov 0xff, %i5 sll %i5, 24, %i5 ! mask 1st byte = 0xff000000 .searchbyte: andcc %l1, %i5, %g0 ! cur byte 0? srl %i5, 8, %i5 ! mask next byte bnz,a %icc, .searchbyte ! cur !=0 continue add %i3, 1, %i3 .endfound: sub %i3, %i1, %i0 ! len = src - orig src ret restore %i0, %g0, %o0 nop .dstnotaligned: cmp %g1, 2 ! halfword aligned? be .storehalfword2 .empty .storebyte: ld [%i3 + %g4], %l1 ! load src word addcc %g4, 4, %g4 ! src +=4 dst +=4 bcs,pn %icc, .lastword andn %i5, %l1, %g1 ! ~x & 0x80808080 sub %l1, %i4, %l0 ! x - 0x01010101 andcc %l0, %g1, %g0 ! get your Mycroft on bnz,pn %icc, .zerobyte ! non-zero, we have zero byte add %i2, %g4, %l0 ! dst in ptr form srl %l1, 24, %g1 ! get 1st byte, then be hw aligned stb %g1, [%l0] srl %l1, 8, %g1 ! 2nd & 3rd bytes sth %g1, [%l0 + 1] ba .storebyte stb %l1, [%l0 + 3] ! store 4th byte .storehalfword: ld [%i3 + %g4], %l1 ! src word .storehalfword2: addcc %g4, 4, %g4 ! src += 4 dst += 4 bcs,pn %icc, .lastword andn %i5, %l1, %g1 ! ~x & 0x80808080 sub %l1, %i4, %l0 ! x - 0x01010101 andcc %l0, %g1, %g0 ! Mycroft again... bnz,pn %icc, .zerobyte ! non-zer, we have zero byte add %i2, %g4, %l0 ! dst in ptr form srl %l1, 16, %g1 ! first two bytes sth %g1, [%l0] ba .storehalfword sth %l1, [%l0 + 2] .forcenullunalign: add %i2, %g4, %i2 ! single dst ptr stb %g0, [%i2 - 1] ! store terminating null byte .getstrlen: sethi %hi(0x01010101), %i4 ! Mycroft... or %i4, %lo(0x01010101), %i4 sll %i4, 7, %i5 .getstrlenloop: andcc %i3, 3, %g0 ! word aligned? bz,a,pn %icc, .searchword2 ! search word at a time ld [%i3], %l1 ! src word ldub [%i3], %l1 ! src byte andcc %l1, 0xff, %g0 ! end of src? bnz,a %icc, .getstrlenloop add %i3, 1, %i3 ! src ++ sub %i3, %i1, %i0 ! len = src - orig src ret restore %i0, %g0, %o0 SET_SIZE(strlcpy)