xref: /titanic_51/usr/src/lib/libc/port/gen/readdir.c (revision df0345f7d6cc87cde9e532e8362f1aca053d98cc)
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 */
162