gen/FreeBSD/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 #include <sys/cdefs.h>
  20 __FBSDID("$FreeBSD: src/lib/libc/gen/dirname.c,v 1.8 2008/11/03 05:19:45 delphij Exp $");
  21
  22 #include <errno.h>
  23 #include <libgen.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/param.h>
  27
  28 char *
  29 dirname(const char *path)
  30 {
  31         static char *dname = NULL;
  32         size_t len;
  33         const char *endp;
  34
  35         if (dname == NULL) {
  36                 dname = (char *)malloc(MAXPATHLEN);
  37                 if (dname == NULL)
  38                         return(NULL);
  39         }
  40
  41         /* Empty or NULL string gets treated as "." */
  42         if (path == NULL || *path == '\0') {
  43                 dname[0] = '.';
  44                 dname[1] = '\0';
  45                 return (dname);
  46         }
  47
  48         /* Strip any trailing slashes */
  49         endp = path + strlen(path) - 1;
  50         while (endp > path && *endp == '/')
  51                 endp--;
  52
  53         /* Find the start of the dir */
  54         while (endp > path && *endp != '/')
  55                 endp--;
  56
  57         /* Either the dir is "/" or there are no slashes */
  58         if (endp == path) {
  59                 dname[0] = *endp == '/' ? '/' : '.';
  60                 dname[1] = '\0';
  61                 return (dname);
  62         } else {
  63                 /* Move forward past the separating slashes */
  64                 do {
  65                         endp--;
  66                 } while (endp > path && *endp == '/');
  67         }
  68
  69         len = endp - path + 1;
  70         if (len >= MAXPATHLEN) {
  71                 errno = ENAMETOOLONG;
  72                 return (NULL);
  73         }
  74         memcpy(dname, path, len);
  75         dname[len] = '\0';
  76         return (dname);
  77 }