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
61dirent_t *
62readdir(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
92dirent64_t *
93readdir64(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 */
133dirent_t *
134readdir(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 */
162