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      1 /** @file
      2     Open a directory.
      3 
      4     Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
      5     This program and the accompanying materials
      6     are licensed and made available under the terms and conditions of the BSD License
      7     which accompanies this distribution.  The full text of the license may be found at
      8     http://opensource.org/licenses/bsd-license.php
      9 
     10     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     11     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     12 
     13     Copyright (c) 1983, 1993
     14     The Regents of the University of California.  All rights reserved.
     15 
     16     Redistribution and use in source and binary forms, with or without
     17     modification, are permitted provided that the following conditions
     18     are met:
     19     1. Redistributions of source code must retain the above copyright
     20       notice, this list of conditions and the following disclaimer.
     21     2. Redistributions in binary form must reproduce the above copyright
     22       notice, this list of conditions and the following disclaimer in the
     23       documentation and/or other materials provided with the distribution.
     24     3. Neither the name of the University nor the names of its contributors
     25       may be used to endorse or promote products derived from this software
     26       without specific prior written permission.
     27 
     28     THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31     ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38     SUCH DAMAGE.
     39 
     40     NetBSD: opendir.c,v 1.33 2008/01/10 09:49:04 elad Exp
     41     opendir.c 8.7 (Berkeley) 12/10/94
     42 **/
     43 #include <sys/cdefs.h>
     44 
     45 #include  <namespace.h>
     46 #include  <reentrant.h>
     47 #include  <extern.h>
     48 #include <sys/param.h>
     49 //#include <sys/mount.h>
     50 #include <sys/stat.h>
     51 
     52 #include <assert.h>
     53 #include <dirent.h>
     54 #include <errno.h>
     55 #include <fcntl.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <unistd.h>
     59 
     60 #define MAXITERATIONS 100
     61 
     62 /*
     63  * Open a directory.
     64  */
     65 DIR *
     66 opendir(const char *name)
     67 {
     68   _DIAGASSERT(name != NULL);
     69 
     70   return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
     71 }
     72 
     73 DIR *
     74 __opendir2(const char *name, int flags)
     75 {
     76   DIR *dirp = NULL;
     77   int fd;
     78   int serrno;
     79   struct stat sb;
     80   int incr;
     81 
     82   _DIAGASSERT(name != NULL);
     83 
     84   if ((fd = open(name, O_RDONLY | O_NONBLOCK, 0)) == -1 ||
     85       fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
     86     goto error;
     87   if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
     88     errno = ENOTDIR;
     89     goto error;
     90   }
     91   if ((dirp = (DIR *)malloc(sizeof(DIR))) == NULL)
     92     goto error;
     93   dirp->dd_buf = NULL;
     94 
     95   /*
     96    * If the machine's page size is an exact multiple of DIRBLKSIZ,
     97    * use a buffer that is cluster boundary aligned.
     98    * Hopefully this can be a big win someday by allowing page trades
     99    * to user space to be done by getdirentries()
    100    */
    101   incr = DIRBLKSIZ;
    102 
    103   dirp->dd_len = incr;
    104   dirp->dd_buf = malloc((size_t)dirp->dd_len);
    105   if (dirp->dd_buf == NULL)
    106     goto error;
    107   dirp->dd_seek = 0;
    108   flags &= ~DTF_REWIND;
    109 
    110   dirp->dd_loc = 0;
    111   dirp->dd_fd = fd;
    112   dirp->dd_flags = flags;
    113 
    114   /*
    115    * Set up seek point for rewinddir.
    116    */
    117 #ifdef _REENTRANT
    118   if (__isthreaded) {
    119     if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
    120       goto error;
    121     mutex_init((mutex_t *)dirp->dd_lock, NULL);
    122   }
    123 #endif
    124   dirp->dd_internal = NULL;
    125   return (dirp);
    126 error:
    127   serrno = errno;
    128   if (dirp && dirp->dd_buf)
    129     free(dirp->dd_buf);
    130   if (dirp)
    131     free(dirp);
    132   if (fd != -1)
    133     (void)close(fd);
    134   errno = serrno;
    135   return NULL;
    136 }
    137