1 /* $OpenBSD: dirname.c,v 1.17 2020/10/20 19:30:14 naddy Exp $ */ 2 3 /* 4 * Copyright (c) 1997, 2004 Todd C. Miller <millert@openbsd.org> 5 * 6 * Permission to use, copy, modify, and 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 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <errno.h> 20 #include <libgen.h> 21 #include <limits.h> 22 #include <string.h> 23 24 /* A slightly modified copy of this file exists in libexec/ld.so */ 25 26 char * 27 dirname(char *path) 28 { 29 static char dname[PATH_MAX]; 30 size_t len; 31 const char *endp; 32 33 /* Empty or NULL string gets treated as "." */ 34 if (path == NULL || *path == '\0') { 35 dname[0] = '.'; 36 dname[1] = '\0'; 37 return (dname); 38 } 39 40 /* Strip any trailing slashes */ 41 endp = path + strlen(path) - 1; 42 while (endp > path && *endp == '/') 43 endp--; 44 45 /* Find the start of the dir */ 46 while (endp > path && *endp != '/') 47 endp--; 48 49 /* Either the dir is "/" or there are no slashes */ 50 if (endp == path) { 51 dname[0] = *endp == '/' ? '/' : '.'; 52 dname[1] = '\0'; 53 return (dname); 54 } else { 55 /* Move forward past the separating slashes */ 56 do { 57 endp--; 58 } while (endp > path && *endp == '/'); 59 } 60 61 len = endp - path + 1; 62 if (len >= sizeof(dname)) { 63 errno = ENAMETOOLONG; 64 return (NULL); 65 } 66 memcpy(dname, path, len); 67 dname[len] = '\0'; 68 return (dname); 69 } 70