lib/libc/gen/dirname.c

   1 /*
   2  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
   3  * 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  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  17  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  18  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
  19  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  *
  27  * $OpenBSD: dirname.c,v 1.4 1999/05/30 17:10:30 espie Exp $
  28  * $FreeBSD: src/lib/libc/gen/dirname.c,v 1.7 2002/12/30 01:41:14 marcel Exp $
  29  * $DragonFly: src/lib/libc/gen/dirname.c,v 1.11 2005/11/13 00:07:42 swildner Exp $
  30  */
  31
  32 #include <errno.h>
  33 #include <libgen.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <sys/param.h>
  37
  38 char *
  39 dirname(const char *path)
  40 {
  41         static char *bname;
  42         const char *endp;
  43
  44         if (bname == NULL) {
  45                 bname = (char *)malloc(MAXPATHLEN);
  46                 if (bname == NULL)
  47                         return(NULL);
  48         }
  49
  50         /* Empty or NULL string gets treated as "." */
  51         if (path == NULL || *path == '\0') {
  52                 strlcpy(bname, ".", MAXPATHLEN);
  53                 return(bname);
  54         }
  55
  56         /* Strip trailing slashes */
  57         endp = path + strlen(path) - 1;
  58         while (endp > path && *endp == '/')
  59                 endp--;
  60
  61         /* Find the start of the dir */
  62         while (endp > path && *endp != '/')
  63                 endp--;
  64
  65         /* Either the dir is "/" or there are no slashes */
  66         if (endp == path) {
  67                 strlcpy(bname, *endp == '/' ? "/" : ".", MAXPATHLEN);
  68                 return(bname);
  69         }
  70
  71         do {
  72                 endp--;
  73         } while (endp > path && *endp == '/');
  74
  75         if (endp - path + 2 > MAXPATHLEN) {
  76                 errno = ENAMETOOLONG;
  77                 return(NULL);
  78         }
  79         strlcpy(bname, path, endp - path + 2);
  80         return(bname);
  81 }