usr/src/lib/libc/port/gen/readdir.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 /*
  31  * University Copyright- Copyright (c) 1982, 1986, 1988
  32  * The Regents of the University of California
  33  * All Rights Reserved
  34  *
  35  * University Acknowledgment- Portions of this document are derived from
  36  * software developed by the University of California, Berkeley, and its
  37  * contributors.
  38  */
  39
  40 #pragma ident   "%Z%%M% %I%     %E% SMI"
  41
  42 /*
  43  * readdir -- C library extension routine
  44  */
  45
  46 #include        <sys/feature_tests.h>
  47
  48 #if !defined(_LP64)
  49 #pragma weak _readdir64 = readdir64
  50 #endif
  51 #pragma weak _readdir = readdir
  52
  53 #include "lint.h"
  54 #include <dirent.h>
  55 #include <limits.h>
  56 #include <errno.h>
  57 #include "libc.h"
  58
  59 #ifdef _LP64
  60
  61 dirent_t *
  62 readdir(DIR *dirp)
  63 {
  64         dirent_t *dp;   /* -> directory data */
  65         int saveloc = 0;
  66
  67         if (dirp->dd_size != 0) {
  68                 dp = (dirent_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];
  69                 saveloc = dirp->dd_loc;         /* save for possible EOF */
  70                 dirp->dd_loc += (int)dp->d_reclen;
  71         }
  72         if (dirp->dd_loc >= dirp->dd_size)
  73                 dirp->dd_loc = dirp->dd_size = 0;
  74
  75         if (dirp->dd_size == 0 &&       /* refill buffer */
  76             (dirp->dd_size = getdents(dirp->dd_fd,
  77             (dirent_t *)(uintptr_t)dirp->dd_buf, DIRBUF)) <= 0) {
  78                 if (dirp->dd_size == 0)         /* This means EOF */
  79                         dirp->dd_loc = saveloc; /* so save for telldir */
  80                 return (NULL);          /* error or EOF */
  81         }
  82
  83         return ((dirent_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc]);
  84 }
  85
  86 #else   /* _LP64 */
  87
  88 /*
  89  * Welcome to the complicated world of large files on a small system.
  90  */
  91
  92 dirent64_t *
  93 readdir64(DIR *dirp)
  94 {
  95         dirent64_t *dp64;       /* -> directory data */
  96         int saveloc = 0;
  97
  98         if (dirp->dd_size != 0) {
  99                 dp64 = (dirent64_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];
 100                 /* was converted by readdir and needs to be reversed */
 101                 if (dp64->d_ino == (ino64_t)-1) {
 102                         dirent_t *dp32;
 103
 104                         dp32 = (dirent_t *)(&dp64->d_off);
 105                         dp64->d_ino = (ino64_t)dp32->d_ino;
 106                         dp64->d_off = (off64_t)dp32->d_off;
 107                         dp64->d_reclen = (unsigned short)(dp32->d_reclen +
 108                             ((char *)&dp64->d_off - (char *)dp64));
 109                 }
 110                 saveloc = dirp->dd_loc;         /* save for possible EOF */
 111                 dirp->dd_loc += (int)dp64->d_reclen;
 112         }
 113         if (dirp->dd_loc >= dirp->dd_size)
 114                 dirp->dd_loc = dirp->dd_size = 0;
 115
 116         if (dirp->dd_size == 0 &&       /* refill buffer */
 117             (dirp->dd_size = getdents64(dirp->dd_fd,
 118             (dirent64_t *)(uintptr_t)dirp->dd_buf, DIRBUF)) <= 0) {
 119                 if (dirp->dd_size == 0)         /* This means EOF */
 120                         dirp->dd_loc = saveloc; /* so save for telldir */
 121                 return (NULL);          /* error or EOF */
 122         }
 123
 124         dp64 = (dirent64_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];
 125         return (dp64);
 126 }
 127
 128 /*
 129  * readdir now does translation of dirent64 entries into dirent entries.
 130  * We rely on the fact that dirents are smaller than dirent64s and we
 131  * reuse the space accordingly.
 132  */
 133 dirent_t *
 134 readdir(DIR *dirp)
 135 {
 136         dirent64_t *dp64;       /* -> directory data */
 137         dirent_t *dp32;         /* -> directory data */
 138
 139         if ((dp64 = readdir64(dirp)) == NULL)
 140                 return (NULL);
 141
 142         /*
 143          * Make sure that the offset fits in 32 bits.
 144          */
 145         if (((off_t)dp64->d_off != dp64->d_off &&
 146             (uint64_t)dp64->d_off > (uint64_t)UINT32_MAX) ||
 147             dp64->d_ino > SIZE_MAX) {
 148                 errno = EOVERFLOW;
 149                 return (NULL);
 150         }
 151
 152         dp32 = (dirent_t *)(&dp64->d_off);
 153         dp32->d_off = (off_t)dp64->d_off;
 154         dp32->d_ino = (ino_t)dp64->d_ino;
 155         dp32->d_reclen = (unsigned short)(dp64->d_reclen -
 156             ((char *)&dp64->d_off - (char *)dp64));
 157         dp64->d_ino = (ino64_t)-1;      /* flag as converted for readdir64 */
 158         /* d_name d_reclen should not move */
 159         return (dp32);
 160 }
 161 #endif  /* _LP64 */