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 * 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