usr/src/lib/libc/port/gen/telldir.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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  * telldir -- C library extension routine
  34  */
  35
  36 #include <sys/isa_defs.h>
  37
  38 #if !defined(_LP64)
  39 #pragma weak _telldir64 = telldir64
  40 #endif
  41 #pragma weak _telldir = telldir
  42
  43 #include "lint.h"
  44 #include "libc.h"
  45 #include <mtlib.h>
  46 #include <dirent.h>
  47 #include <errno.h>
  48 #include <limits.h>
  49 #include <fcntl.h>
  50 #include <unistd.h>
  51
  52 #ifdef _LP64
  53
  54 long
  55 telldir(DIR *dirp)
  56 {
  57         private_DIR     *pdirp = (private_DIR *)dirp;
  58         dirent_t        *dp;
  59         off_t           off = 0;
  60
  61         lmutex_lock(&pdirp->dd_lock);
  62         /* if at beginning of dir, return 0 */
  63         if (lseek(dirp->dd_fd, 0, SEEK_CUR) != 0) {
  64                 dp = (dirent_t *)(uintptr_t)(&dirp->dd_buf[dirp->dd_loc]);
  65                 off = dp->d_off;
  66         }
  67         lmutex_unlock(&pdirp->dd_lock);
  68         return (off);
  69 }
  70
  71 #else
  72
  73 /*
  74  * Note: Instead of making this function static, we reduce it to local
  75  * scope in the mapfile. That allows the linker to prevent it from
  76  * appearing in the .SUNW_dynsymsort section.
  77  */
  78 off64_t
  79 telldir64(DIR *dirp)
  80 {
  81         private_DIR     *pdirp = (private_DIR *)(uintptr_t)dirp;
  82         dirent64_t      *dp64;
  83         off64_t         off = 0;
  84
  85         lmutex_lock(&pdirp->dd_lock);
  86         /* if at beginning of dir, return 0 */
  87         if (lseek64(dirp->dd_fd, 0, SEEK_CUR) != 0) {
  88                 dp64 = (dirent64_t *)(uintptr_t)(&dirp->dd_buf[dirp->dd_loc]);
  89                 /* was converted by readdir and needs to be reversed */
  90                 if (dp64->d_ino == (ino64_t)-1) {
  91                         dirent_t *dp32;
  92
  93                         dp32 = (dirent_t *)((uintptr_t)dp64 + sizeof (ino64_t));
  94                         dp64->d_ino = (ino64_t)dp32->d_ino;
  95                         dp64->d_off = (off64_t)dp32->d_off;
  96                         dp64->d_reclen = (unsigned short)(dp32->d_reclen +
  97                             ((char *)&dp64->d_off - (char *)dp64));
  98                 }
  99                 off = dp64->d_off;
 100         }
 101         lmutex_unlock(&pdirp->dd_lock);
 102         return (off);
 103 }
 104
 105 long
 106 telldir(DIR *dirp)
 107 {
 108         off64_t off;
 109
 110         off = telldir64(dirp);
 111
 112         /*
 113          * Make sure that the offset fits in 32 bits.
 114          */
 115         if ((long)off != off && (uint64_t)off > (uint64_t)UINT32_MAX) {
 116                 errno = EOVERFLOW;
 117                 return (-1);
 118         }
 119         return ((long)off);
 120 }
 121
 122 #endif  /* _LP64 */