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 #include <errno.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include "pathconv.h" /* prototypes */
30 /*
31 * rel2abs: convert an relative path name into absolute.
32 *
33 * i) path relative path
34 * i) base base directory (must be absolute path)
35 * o) result result buffer
36 * i) size size of result buffer
37 * r) != NULL: absolute path
38 * == NULL: error
39 */
40 char *
rel2abs(const char * path,const char * base,char * result,const size_t size)41 rel2abs(const char *path, const char *base, char *result, const size_t size)
42 {
43 const char *pp, *bp;
44 /*
45 * endp points the last position which is safe in the result buffer.
46 */
47 const char *endp = result + size - 1;
48 char *rp;
49 size_t length;
50
51 if (*path == '/') {
52 if (strlen(path) >= size)
53 goto erange;
54 strcpy(result, path);
55 goto finish;
56 } else if (*base != '/' || !size) {
57 errno = EINVAL;
58 return (NULL);
59 } else if (size == 1)
60 goto erange;
61
62 length = strlen(base);
63
64 if (!strcmp(path, ".") || !strcmp(path, "./")) {
65 if (length >= size)
66 goto erange;
67 strcpy(result, base);
68 /*
69 * rp points the last char.
70 */
71 rp = result + length - 1;
72 /*
73 * remove the last '/'.
74 */
75 if (*rp == '/') {
76 if (length > 1)
77 *rp = 0;
78 } else
79 rp++;
80 /* rp point NULL char */
81 if (*++path == '/') {
82 /*
83 * Append '/' to the tail of path name.
84 */
85 *rp++ = '/';
86 if (rp > endp)
87 goto erange;
88 *rp = 0;
89 }
90 goto finish;
91 }
92 bp = base + length;
93 if (*(bp - 1) == '/')
94 --bp;
95 /*
96 * up to root.
97 */
98 for (pp = path; *pp && *pp == '.'; ) {
99 if (!strncmp(pp, "../", 3)) {
100 pp += 3;
101 while (bp > base && *--bp != '/')
102 ;
103 } else if (!strncmp(pp, "./", 2)) {
104 pp += 2;
105 } else if (!strncmp(pp, "..\0", 3)) {
106 pp += 2;
107 while (bp > base && *--bp != '/')
108 ;
109 } else
110 break;
111 }
112 /*
113 * down to leaf.
114 */
115 length = bp - base;
116 if (length >= size)
117 goto erange;
118 strncpy(result, base, length);
119 rp = result + length;
120 if (*pp || *(pp - 1) == '/' || length == 0)
121 *rp++ = '/';
122 if (rp + strlen(pp) > endp)
123 goto erange;
124 strcpy(rp, pp);
125 finish:
126 return result;
127 erange:
128 errno = ERANGE;
129 return (NULL);
130 }
131