gen/FreeBSD/readdir.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)readdir.c   8.3 (Berkeley) 9/29/94";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD$");
  35
  36 #include "namespace.h"
  37 #include <sys/param.h>
  38 #include <dirent.h>
  39 #include <errno.h>
  40 #include <string.h>
  41 #include <pthread.h>
  42 #include "un-namespace.h"
  43
  44 #include "libc_private.h"
  45 #include "telldir.h"
  46
  47 /*
  48  * get next entry in a directory.
  49  */
  50 struct dirent *
  51 _readdir_unlocked(DIR *dirp, int skip)
  52 {
  53         struct dirent *dp;
  54         long initial_seek;
  55         long initial_loc = 0;
  56
  57         for (;;) {
  58                 if (dirp->dd_loc >= dirp->dd_size) {
  59                         if (dirp->dd_flags & __DTF_READALL)
  60                                 return (NULL);
  61                         initial_loc = dirp->dd_loc;
  62                         dirp->dd_flags &= ~__DTF_SKIPREAD;
  63                         dirp->dd_loc = 0;
  64                 }
  65                 if (dirp->dd_loc == 0 &&
  66                     !(dirp->dd_flags & (__DTF_READALL | __DTF_SKIPREAD))) {
  67 #if __DARWIN_64_BIT_INO_T
  68                         initial_seek = dirp->dd_td->seekoff;
  69                         dirp->dd_size = (long)__getdirentries64(dirp->dd_fd,
  70                             dirp->dd_buf, dirp->dd_len, &dirp->dd_td->seekoff);
  71 #else /* !__DARWIN_64_BIT_INO_T */
  72                         initial_seek = dirp->dd_seek;
  73                         dirp->dd_size = _getdirentries(dirp->dd_fd,
  74                             dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
  75 #endif /* __DARWIN_64_BIT_INO_T */
  76                         if (dirp->dd_size <= 0)
  77                                 return (NULL);
  78                         _fixtelldir(dirp, initial_seek, initial_loc);
  79                 }
  80                 dirp->dd_flags &= ~__DTF_SKIPREAD;
  81                 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  82                 if ((long)dp & 03L)     /* bogus pointer check */
  83                         return (NULL);
  84                 if (dp->d_reclen <= 0 ||
  85                     dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
  86                         return (NULL);
  87                 dirp->dd_loc += dp->d_reclen;
  88                 if (dp->d_ino == 0 && skip)
  89                         continue;
  90                 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  91                         continue;
  92                 return (dp);
  93         }
  94 }
  95
  96 struct dirent *
  97 readdir(DIR *dirp)
  98 {
  99         struct dirent   *dp;
 100
 101         if (__isthreaded) {
 102                 _pthread_mutex_lock(&dirp->dd_lock);
 103                 dp = _readdir_unlocked(dirp, 1);
 104                 _pthread_mutex_unlock(&dirp->dd_lock);
 105         }
 106         else
 107                 dp = _readdir_unlocked(dirp, 1);
 108         return (dp);
 109 }
 110
 111 int
 112 readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
 113 {
 114         struct dirent *dp;
 115         int saved_errno;
 116
 117         saved_errno = errno;
 118         errno = 0;
 119         if (__isthreaded) {
 120                 _pthread_mutex_lock(&dirp->dd_lock);
 121                 if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 122                         memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
 123                 _pthread_mutex_unlock(&dirp->dd_lock);
 124         }
 125         else if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 126                 memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
 127
 128         if (errno != 0) {
 129                 if (dp == NULL)
 130                         return (errno);
 131         } else
 132                 errno = saved_errno;
 133
 134         if (dp != NULL)
 135                 *result = entry;
 136         else
 137                 *result = NULL;
 138
 139         return (0);
 140 }