usr/src/lib/libc/port/gen/dirname.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  *      Return pointer to the directory name, stripping off the last
  34  *      component of the path.
  35  *      Works similar to /bin/dirname
  36  */
  37
  38 #pragma weak _dirname = dirname
  39
  40 #include "lint.h"
  41 #include <sys/types.h>
  42 #include <string.h>
  43
  44 char *
  45 dirname(char *s)
  46 {
  47         char    *p;
  48
  49         if (!s || !*s)                  /* zero or empty argument */
  50                 return (".");
  51
  52         p = s + strlen(s);
  53         while (p != s && *--p == '/')   /* trim trailing /s */
  54                 ;
  55
  56         if (p == s && *p == '/')
  57                 return ("/");
  58
  59         while (p != s)
  60                 if (*--p == '/') {
  61                         while (*p == '/' && p != s)
  62                                 p--;
  63                         *++p = '\0';
  64                         return (s);
  65                 }
  66
  67         return (".");
  68 }