1*0f7f3352SJulian Elischer /* 2*0f7f3352SJulian Elischer * Copyright (c) 1997 Shigio Yamaguchi. All rights reserved. 3*0f7f3352SJulian Elischer * Copyright (c) 1999 Tama Communications Corporation. All rights reserved. 4*0f7f3352SJulian Elischer * 5*0f7f3352SJulian Elischer * Redistribution and use in source and binary forms, with or without 6*0f7f3352SJulian Elischer * modification, are permitted provided that the following conditions 7*0f7f3352SJulian Elischer * are met: 8*0f7f3352SJulian Elischer * 1. Redistributions of source code must retain the above copyright 9*0f7f3352SJulian Elischer * notice, this list of conditions and the following disclaimer. 10*0f7f3352SJulian Elischer * 2. Redistributions in binary form must reproduce the above copyright 11*0f7f3352SJulian Elischer * notice, this list of conditions and the following disclaimer in the 12*0f7f3352SJulian Elischer * documentation and/or other materials provided with the distribution. 13*0f7f3352SJulian Elischer * 14*0f7f3352SJulian Elischer * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15*0f7f3352SJulian Elischer * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16*0f7f3352SJulian Elischer * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17*0f7f3352SJulian Elischer * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18*0f7f3352SJulian Elischer * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19*0f7f3352SJulian Elischer * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20*0f7f3352SJulian Elischer * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21*0f7f3352SJulian Elischer * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22*0f7f3352SJulian Elischer * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23*0f7f3352SJulian Elischer * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24*0f7f3352SJulian Elischer * SUCH DAMAGE. 25*0f7f3352SJulian Elischer * 26*0f7f3352SJulian Elischer * $FreeBSD$ 27*0f7f3352SJulian Elischer */ 28*0f7f3352SJulian Elischer #include <errno.h> 29*0f7f3352SJulian Elischer #include <stdlib.h> 30*0f7f3352SJulian Elischer #include <string.h> 31*0f7f3352SJulian Elischer #include "pathconv.h" /* prototypes */ 32*0f7f3352SJulian Elischer /* 33*0f7f3352SJulian Elischer * abs2rel: convert an absolute path name into relative. 34*0f7f3352SJulian Elischer * 35*0f7f3352SJulian Elischer * i) path absolute path 36*0f7f3352SJulian Elischer * i) base base directory (must be absolute path) 37*0f7f3352SJulian Elischer * o) result result buffer 38*0f7f3352SJulian Elischer * i) size size of result buffer 39*0f7f3352SJulian Elischer * r) != NULL: relative path 40*0f7f3352SJulian Elischer * == NULL: error 41*0f7f3352SJulian Elischer */ 42*0f7f3352SJulian Elischer char * 43*0f7f3352SJulian Elischer abs2rel(const char *path, const char *base, char *result, const size_t size) 44*0f7f3352SJulian Elischer { 45*0f7f3352SJulian Elischer const char *pp, *bp, *branch; 46*0f7f3352SJulian Elischer /* 47*0f7f3352SJulian Elischer * endp points the last position which is safe in the result buffer. 48*0f7f3352SJulian Elischer */ 49*0f7f3352SJulian Elischer const char *endp = result + size - 1; 50*0f7f3352SJulian Elischer char *rp; 51*0f7f3352SJulian Elischer 52*0f7f3352SJulian Elischer if (*path != '/') { 53*0f7f3352SJulian Elischer if (strlen(path) >= size) 54*0f7f3352SJulian Elischer goto erange; 55*0f7f3352SJulian Elischer strcpy(result, path); 56*0f7f3352SJulian Elischer goto finish; 57*0f7f3352SJulian Elischer } else if (*base != '/' || !size) { 58*0f7f3352SJulian Elischer errno = EINVAL; 59*0f7f3352SJulian Elischer return (NULL); 60*0f7f3352SJulian Elischer } else if (size == 1) 61*0f7f3352SJulian Elischer goto erange; 62*0f7f3352SJulian Elischer /* 63*0f7f3352SJulian Elischer * seek to branched point. 64*0f7f3352SJulian Elischer */ 65*0f7f3352SJulian Elischer branch = path; 66*0f7f3352SJulian Elischer for (pp = path, bp = base; *pp && *bp && *pp == *bp; pp++, bp++) 67*0f7f3352SJulian Elischer if (*pp == '/') 68*0f7f3352SJulian Elischer branch = pp; 69*0f7f3352SJulian Elischer if ((*pp == 0 || (*pp == '/' && *(pp + 1) == 0)) && 70*0f7f3352SJulian Elischer (*bp == 0 || (*bp == '/' && *(bp + 1) == 0))) { 71*0f7f3352SJulian Elischer rp = result; 72*0f7f3352SJulian Elischer *rp++ = '.'; 73*0f7f3352SJulian Elischer if (*pp == '/' || *(pp - 1) == '/') 74*0f7f3352SJulian Elischer *rp++ = '/'; 75*0f7f3352SJulian Elischer if (rp > endp) 76*0f7f3352SJulian Elischer goto erange; 77*0f7f3352SJulian Elischer *rp = 0; 78*0f7f3352SJulian Elischer goto finish; 79*0f7f3352SJulian Elischer } 80*0f7f3352SJulian Elischer if ((*pp == 0 && *bp == '/') || (*pp == '/' && *bp == 0)) 81*0f7f3352SJulian Elischer branch = pp; 82*0f7f3352SJulian Elischer /* 83*0f7f3352SJulian Elischer * up to root. 84*0f7f3352SJulian Elischer */ 85*0f7f3352SJulian Elischer rp = result; 86*0f7f3352SJulian Elischer for (bp = base + (branch - path); *bp; bp++) 87*0f7f3352SJulian Elischer if (*bp == '/' && *(bp + 1) != 0) { 88*0f7f3352SJulian Elischer if (rp + 3 > endp) 89*0f7f3352SJulian Elischer goto erange; 90*0f7f3352SJulian Elischer *rp++ = '.'; 91*0f7f3352SJulian Elischer *rp++ = '.'; 92*0f7f3352SJulian Elischer *rp++ = '/'; 93*0f7f3352SJulian Elischer } 94*0f7f3352SJulian Elischer if (rp > endp) 95*0f7f3352SJulian Elischer goto erange; 96*0f7f3352SJulian Elischer *rp = 0; 97*0f7f3352SJulian Elischer /* 98*0f7f3352SJulian Elischer * down to leaf. 99*0f7f3352SJulian Elischer */ 100*0f7f3352SJulian Elischer if (*branch) { 101*0f7f3352SJulian Elischer if (rp + strlen(branch + 1) > endp) 102*0f7f3352SJulian Elischer goto erange; 103*0f7f3352SJulian Elischer strcpy(rp, branch + 1); 104*0f7f3352SJulian Elischer } else 105*0f7f3352SJulian Elischer *--rp = 0; 106*0f7f3352SJulian Elischer finish: 107*0f7f3352SJulian Elischer return result; 108*0f7f3352SJulian Elischer erange: 109*0f7f3352SJulian Elischer errno = ERANGE; 110*0f7f3352SJulian Elischer return (NULL); 111*0f7f3352SJulian Elischer } 112