1 /* $OpenBSD: realpath.c,v 1.26 2019/06/17 03:13:17 deraadt Exp $ */ 2 /* 3 * Copyright (c) 2019 Bob Beck <beck@openbsd.org> 4 * Copyright (c) 2019 Theo de Raadt <deraadt@openbsd.org> 5 * 6 * Permission to use, copy, modify, and/or distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 13 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 15 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 16 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <errno.h> 20 #include <stdlib.h> 21 #include <string.h> 22 #include <unistd.h> 23 #include <limits.h> 24 #include <syslog.h> 25 #include <stdarg.h> 26 27 int __realpath(const char *pathname, char *resolved); 28 PROTO_NORMAL(__realpath); 29 30 /* 31 * wrapper for kernel __realpath 32 */ 33 34 char * 35 realpath(const char *path, char *resolved) 36 { 37 char rbuf[PATH_MAX]; 38 39 if (__realpath(path, rbuf) == -1) { 40 /* 41 * XXX XXX XXX 42 * 43 * The old userland implementation strips trailing slashes. 44 * According to Dr. POSIX, realpathing "/bsd" should be fine, 45 * realpathing "/bsd/" should return ENOTDIR. 46 * 47 * Similar, but *different* to the above, The old userland 48 * implementation allows for realpathing "/nonexistent" but 49 * not "/nonexistent/", Both those should return ENOENT 50 * according to POSIX. 51 * 52 * This hack should go away once we decide to match POSIX. 53 * which we should as soon as is convenient. 54 */ 55 if (errno == ENOTDIR) { 56 char pbuf[PATH_MAX]; 57 ssize_t i; 58 59 if (strlcpy(pbuf, path, sizeof(pbuf)) >= sizeof(pbuf)) { 60 errno = ENAMETOOLONG; 61 return NULL; 62 } 63 /* Try again without the trailing slashes. */ 64 for (i = strlen(pbuf); i > 1 && pbuf[i - 1] == '/'; i--) 65 pbuf[i - 1] = '\0'; 66 if (__realpath(pbuf, rbuf) == -1) 67 return NULL; 68 } else 69 return NULL; 70 } 71 72 if (resolved == NULL) 73 return (strdup(rbuf)); 74 strlcpy(resolved, rbuf, PATH_MAX); 75 return (resolved); 76 } 77