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 #include <errno.h>
27*0f7f3352SJulian Elischer #include <stdlib.h>
28*0f7f3352SJulian Elischer #include <string.h>
29*0f7f3352SJulian Elischer #include "pathconv.h" /* prototypes */
30*0f7f3352SJulian Elischer /*
31*0f7f3352SJulian Elischer * abs2rel: convert an absolute path name into relative.
32*0f7f3352SJulian Elischer *
33*0f7f3352SJulian Elischer * i) path absolute path
34*0f7f3352SJulian Elischer * i) base base directory (must be absolute path)
35*0f7f3352SJulian Elischer * o) result result buffer
36*0f7f3352SJulian Elischer * i) size size of result buffer
37*0f7f3352SJulian Elischer * r) != NULL: relative path
38*0f7f3352SJulian Elischer * == NULL: error
39*0f7f3352SJulian Elischer */
40*0f7f3352SJulian Elischer char *
abs2rel(const char * path,const char * base,char * result,const size_t size)41*0f7f3352SJulian Elischer abs2rel(const char *path, const char *base, char *result, const size_t size)
42*0f7f3352SJulian Elischer {
43*0f7f3352SJulian Elischer const char *pp, *bp, *branch;
44*0f7f3352SJulian Elischer /*
45*0f7f3352SJulian Elischer * endp points the last position which is safe in the result buffer.
46*0f7f3352SJulian Elischer */
47*0f7f3352SJulian Elischer const char *endp = result + size - 1;
48*0f7f3352SJulian Elischer char *rp;
49*0f7f3352SJulian Elischer
50*0f7f3352SJulian Elischer if (*path != '/') {
51*0f7f3352SJulian Elischer if (strlen(path) >= size)
52*0f7f3352SJulian Elischer goto erange;
53*0f7f3352SJulian Elischer strcpy(result, path);
54*0f7f3352SJulian Elischer goto finish;
55*0f7f3352SJulian Elischer } else if (*base != '/' || !size) {
56*0f7f3352SJulian Elischer errno = EINVAL;
57*0f7f3352SJulian Elischer return (NULL);
58*0f7f3352SJulian Elischer } else if (size == 1)
59*0f7f3352SJulian Elischer goto erange;
60*0f7f3352SJulian Elischer /*
61*0f7f3352SJulian Elischer * seek to branched point.
62*0f7f3352SJulian Elischer */
63*0f7f3352SJulian Elischer branch = path;
64*0f7f3352SJulian Elischer for (pp = path, bp = base; *pp && *bp && *pp == *bp; pp++, bp++)
65*0f7f3352SJulian Elischer if (*pp == '/')
66*0f7f3352SJulian Elischer branch = pp;
67*0f7f3352SJulian Elischer if ((*pp == 0 || (*pp == '/' && *(pp + 1) == 0)) &&
68*0f7f3352SJulian Elischer (*bp == 0 || (*bp == '/' && *(bp + 1) == 0))) {
69*0f7f3352SJulian Elischer rp = result;
70*0f7f3352SJulian Elischer *rp++ = '.';
71*0f7f3352SJulian Elischer if (*pp == '/' || *(pp - 1) == '/')
72*0f7f3352SJulian Elischer *rp++ = '/';
73*0f7f3352SJulian Elischer if (rp > endp)
74*0f7f3352SJulian Elischer goto erange;
75*0f7f3352SJulian Elischer *rp = 0;
76*0f7f3352SJulian Elischer goto finish;
77*0f7f3352SJulian Elischer }
78*0f7f3352SJulian Elischer if ((*pp == 0 && *bp == '/') || (*pp == '/' && *bp == 0))
79*0f7f3352SJulian Elischer branch = pp;
80*0f7f3352SJulian Elischer /*
81*0f7f3352SJulian Elischer * up to root.
82*0f7f3352SJulian Elischer */
83*0f7f3352SJulian Elischer rp = result;
84*0f7f3352SJulian Elischer for (bp = base + (branch - path); *bp; bp++)
85*0f7f3352SJulian Elischer if (*bp == '/' && *(bp + 1) != 0) {
86*0f7f3352SJulian Elischer if (rp + 3 > endp)
87*0f7f3352SJulian Elischer goto erange;
88*0f7f3352SJulian Elischer *rp++ = '.';
89*0f7f3352SJulian Elischer *rp++ = '.';
90*0f7f3352SJulian Elischer *rp++ = '/';
91*0f7f3352SJulian Elischer }
92*0f7f3352SJulian Elischer if (rp > endp)
93*0f7f3352SJulian Elischer goto erange;
94*0f7f3352SJulian Elischer *rp = 0;
95*0f7f3352SJulian Elischer /*
96*0f7f3352SJulian Elischer * down to leaf.
97*0f7f3352SJulian Elischer */
98*0f7f3352SJulian Elischer if (*branch) {
99*0f7f3352SJulian Elischer if (rp + strlen(branch + 1) > endp)
100*0f7f3352SJulian Elischer goto erange;
101*0f7f3352SJulian Elischer strcpy(rp, branch + 1);
102*0f7f3352SJulian Elischer } else
103*0f7f3352SJulian Elischer *--rp = 0;
104*0f7f3352SJulian Elischer finish:
105*0f7f3352SJulian Elischer return result;
106*0f7f3352SJulian Elischer erange:
107*0f7f3352SJulian Elischer errno = ERANGE;
108*0f7f3352SJulian Elischer return (NULL);
109*0f7f3352SJulian Elischer }
110