gen/FreeBSD/telldir.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[] = "@(#)telldir.c   8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/telldir.c,v 1.11 2008/05/05 14:05:23 kib Exp $");
  35
  36 #include "namespace.h"
  37 #include <sys/param.h>
  38 #include <sys/queue.h>
  39 #include <dirent.h>
  40 #include <pthread.h>
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include "un-namespace.h"
  44
  45 #include "libc_private.h"
  46 #include "telldir.h"
  47
  48 /*
  49  * The option SINGLEUSE may be defined to say that a telldir
  50  * cookie may be used only once before it is freed. This option
  51  * is used to avoid having memory usage grow without bound.
  52  */
  53 #if !__DARWIN_UNIX03
  54 #define SINGLEUSE
  55 #endif /* !__DARWIN_UNIX03 */
  56
  57 /*
  58  * return a pointer into a directory
  59  */
  60 long
  61 telldir(dirp)
  62         DIR *dirp;
  63 {
  64         struct ddloc *lp;
  65
  66 #if __DARWIN_UNIX03
  67         if (__isthreaded)
  68                 _pthread_mutex_lock(&dirp->dd_lock);
  69         LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
  70                 if (
  71 #if __DARWIN_64_BIT_INO_T
  72                     (lp->loc_seek == dirp->dd_td->seekoff)
  73 #else /* !__DARWIN_64_BIT_INO_T */
  74                     (lp->loc_seek == dirp->dd_seek)
  75 #endif /* __DARWIN_64_BIT_INO_T */
  76                     && (lp->loc_loc == dirp->dd_loc))
  77                         goto found;
  78         }
  79         if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL) {
  80                 if (__isthreaded)
  81                         _pthread_mutex_unlock(&dirp->dd_lock);
  82                 return (-1);
  83         }
  84 #else /* !__DARWIN_UNIX03 */
  85         if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL)
  86                 return (-1);
  87         if (__isthreaded)
  88                 _pthread_mutex_lock(&dirp->dd_lock);
  89 #endif /* __DARWIN_UNIX03 */
  90         lp->loc_index = dirp->dd_td->td_loccnt++;
  91 #if __DARWIN_64_BIT_INO_T
  92         lp->loc_seek = dirp->dd_td->seekoff;
  93 #else /* !__DARWIN_64_BIT_INO_T */
  94         lp->loc_seek = dirp->dd_seek;
  95 #endif /* __DARWIN_64_BIT_INO_T */
  96         lp->loc_loc = dirp->dd_loc;
  97         LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe);
  98 #if __DARWIN_UNIX03
  99 found:
 100 #endif /* __DARWIN_UNIX03 */
 101         if (__isthreaded)
 102                 _pthread_mutex_unlock(&dirp->dd_lock);
 103         return (lp->loc_index);
 104 }
 105
 106 /*
 107  * seek to an entry in a directory.
 108  * Only values returned by "telldir" should be passed to seekdir.
 109  */
 110 void
 111 _seekdir(dirp, loc)
 112         DIR *dirp;
 113         long loc;
 114 {
 115         struct ddloc *lp;
 116         struct dirent *dp;
 117
 118         LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
 119                 if (lp->loc_index == loc)
 120                         break;
 121         }
 122         if (lp == NULL)
 123                 return;
 124         if (lp->loc_loc == dirp->dd_loc &&
 125 #if __DARWIN_64_BIT_INO_T
 126             lp->loc_seek == dirp->dd_td->seekoff
 127 #else /* !__DARWIN_64_BIT_INO_T */
 128             lp->loc_seek == dirp->dd_seek
 129 #endif /* __DARWIN_64_BIT_INO_T */
 130         )
 131                 goto found;
 132         (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
 133 #if __DARWIN_64_BIT_INO_T
 134         dirp->dd_td->seekoff = lp->loc_seek;
 135 #else /* !__DARWIN_64_BIT_INO_T */
 136         dirp->dd_seek = lp->loc_seek;
 137 #endif /* __DARWIN_64_BIT_INO_T */
 138         dirp->dd_loc = 0;
 139         while (dirp->dd_loc < lp->loc_loc) {
 140                 dp = _readdir_unlocked(dirp, 0);
 141                 if (dp == NULL)
 142                         break;
 143         }
 144 found:;
 145 #ifdef SINGLEUSE
 146         LIST_REMOVE(lp, loc_lqe);
 147         free((caddr_t)lp);
 148 #endif
 149 }
 150
 151 #ifndef BUILDING_VARIANT
 152 /*
 153  * Reclaim memory for telldir cookies which weren't used.
 154  */
 155 void
 156 _reclaim_telldir(dirp)
 157         DIR *dirp;
 158 {
 159         struct ddloc *lp;
 160         struct ddloc *templp;
 161
 162         lp = LIST_FIRST(&dirp->dd_td->td_locq);
 163         while (lp != NULL) {
 164                 templp = lp;
 165                 lp = LIST_NEXT(lp, loc_lqe);
 166                 free(templp);
 167         }
 168         LIST_INIT(&dirp->dd_td->td_locq);
 169 }
 170 #endif /* !BUILDING_VARIANT */