openbsd-compat/dirname.c

   1 /*      $OpenBSD: dirname.c,v 1.13 2005/08/08 08:05:33 espie Exp $      */
   2
   3 /*
   4  * Copyright (c) 1997, 2004 Todd C. Miller <Todd.Miller@courtesan.com>
   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 /* OPENBSD ORIGINAL: lib/libc/gen/dirname.c */
  20
  21 #include "includes.h"
  22 #ifndef HAVE_DIRNAME
  23
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <sys/param.h>
  27
  28 char *
  29 dirname(const char *path)
  30 {
  31         static char dname[MAXPATHLEN];
  32         size_t len;
  33         const char *endp;
  34
  35         /* Empty or NULL string gets treated as "." */
  36         if (path == NULL || *path == '\0') {
  37                 dname[0] = '.';
  38                 dname[1] = '\0';
  39                 return (dname);
  40         }
  41
  42         /* Strip any trailing slashes */
  43         endp = path + strlen(path) - 1;
  44         while (endp > path && *endp == '/')
  45                 endp--;
  46
  47         /* Find the start of the dir */
  48         while (endp > path && *endp != '/')
  49                 endp--;
  50
  51         /* Either the dir is "/" or there are no slashes */
  52         if (endp == path) {
  53                 dname[0] = *endp == '/' ? '/' : '.';
  54                 dname[1] = '\0';
  55                 return (dname);
  56         } else {
  57                 /* Move forward past the separating slashes */
  58                 do {
  59                         endp--;
  60                 } while (endp > path && *endp == '/');
  61         }
  62
  63         len = endp - path + 1;
  64         if (len >= sizeof(dname)) {
  65                 errno = ENAMETOOLONG;
  66                 return (NULL);
  67         }
  68         memcpy(dname, path, len);
  69         dname[len] = '\0';
  70         return (dname);
  71 }
  72 #endif