1 /*
2 * Copyright (c) 1997 Shigio Yamaguchi. All rights reserved.
3 * Copyright (c) 1999 Tama Communications Corporation. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28 #include <errno.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include "pathconv.h" /* prototypes */
32 /*
33 * rel2abs: convert an relative path name into absolute.
34 *
35 * i) path relative path
36 * i) base base directory (must be absolute path)
37 * o) result result buffer
38 * i) size size of result buffer
39 * r) != NULL: absolute path
40 * == NULL: error
41 */
42 char *
rel2abs(const char * path,const char * base,char * result,const size_t size)43 rel2abs(const char *path, const char *base, char *result, const size_t size)
44 {
45 const char *pp, *bp;
46 /*
47 * endp points the last position which is safe in the result buffer.
48 */
49 const char *endp = result + size - 1;
50 char *rp;
51 size_t length;
52
53 if (*path == '/') {
54 if (strlen(path) >= size)
55 goto erange;
56 strcpy(result, path);
57 goto finish;
58 } else if (*base != '/' || !size) {
59 errno = EINVAL;
60 return (NULL);
61 } else if (size == 1)
62 goto erange;
63
64 length = strlen(base);
65
66 if (!strcmp(path, ".") || !strcmp(path, "./")) {
67 if (length >= size)
68 goto erange;
69 strcpy(result, base);
70 /*
71 * rp points the last char.
72 */
73 rp = result + length - 1;
74 /*
75 * remove the last '/'.
76 */
77 if (*rp == '/') {
78 if (length > 1)
79 *rp = 0;
80 } else
81 rp++;
82 /* rp point NULL char */
83 if (*++path == '/') {
84 /*
85 * Append '/' to the tail of path name.
86 */
87 *rp++ = '/';
88 if (rp > endp)
89 goto erange;
90 *rp = 0;
91 }
92 goto finish;
93 }
94 bp = base + length;
95 if (*(bp - 1) == '/')
96 --bp;
97 /*
98 * up to root.
99 */
100 for (pp = path; *pp && *pp == '.'; ) {
101 if (!strncmp(pp, "../", 3)) {
102 pp += 3;
103 while (bp > base && *--bp != '/')
104 ;
105 } else if (!strncmp(pp, "./", 2)) {
106 pp += 2;
107 } else if (!strncmp(pp, "..\0", 3)) {
108 pp += 2;
109 while (bp > base && *--bp != '/')
110 ;
111 } else
112 break;
113 }
114 /*
115 * down to leaf.
116 */
117 length = bp - base;
118 if (length >= size)
119 goto erange;
120 strncpy(result, base, length);
121 rp = result + length;
122 if (*pp || *(pp - 1) == '/' || length == 0)
123 *rp++ = '/';
124 if (rp + strlen(pp) > endp)
125 goto erange;
126 strcpy(rp, pp);
127 finish:
128 return result;
129 erange:
130 errno = ERANGE;
131 return (NULL);
132 }
133