lib/libc/gen/dirname.c

   1 /*      $NetBSD: dirname.c,v 1.10 2008/05/10 22:39:40 christos Exp $    */
   2
   3 /*-
   4  * Copyright (c) 1997, 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Klaus Klein and Jason R. Thorpe.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: dirname.c,v 1.10 2008/05/10 22:39:40 christos Exp $");
  35 #endif /* !LIBC_SCCS && !lint */
  36
  37 #include "namespace.h"
  38 #include <libgen.h>
  39 #include <limits.h>
  40 #include <string.h>
  41
  42 #ifdef __weak_alias
  43 __weak_alias(dirname,_dirname)
  44 #endif
  45
  46 #if !HAVE_DIRNAME
  47 char *
  48 dirname(char *path)
  49 {
  50         static char result[PATH_MAX];
  51         const char *lastp;
  52         size_t len;
  53
  54         /*
  55          * If `path' is a null pointer or points to an empty string,
  56          * return a pointer to the string ".".
  57          */
  58         if ((path == NULL) || (*path == '\0'))
  59                 goto singledot;
  60
  61
  62         /* Strip trailing slashes, if any. */
  63         lastp = path + strlen(path) - 1;
  64         while (lastp != path && *lastp == '/')
  65                 lastp--;
  66
  67         /* Terminate path at the last occurence of '/'. */
  68         do {
  69                 if (*lastp == '/') {
  70                         /* Strip trailing slashes, if any. */
  71                         while (lastp != path && *lastp == '/')
  72                                 lastp--;
  73
  74                         /* ...and copy the result into the result buffer. */
  75                         len = (lastp - path) + 1 /* last char */;
  76                         if (len > (PATH_MAX - 1))
  77                                 len = PATH_MAX - 1;
  78
  79                         memcpy(result, path, len);
  80                         result[len] = '\0';
  81
  82                         return (result);
  83                 }
  84         } while (--lastp >= path);
  85
  86         /* No /'s found, return a pointer to the string ".". */
  87 singledot:
  88         result[0] = '.';
  89         result[1] = '\0';
  90
  91         return (result);
  92 }
  93 #endif