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 * 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