xref: /illumos-gate/usr/src/lib/libc/port/gen/telldir.c (revision 7257d1b4)
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
telldir(DIR * dirp)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
telldir64(DIR * dirp)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
telldir(DIR * dirp)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 */
123