xref: /titanic_41/usr/src/lib/libtnf/access.c (revision 355b4669e025ff377602b6fc7caaf30dbc218371)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  *	Copyright (c) 1994, by Sun Microsytems, Inc.
24  */
25 
26 #pragma	ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include "libtnf.h"
29 
30 /*
31  * File header operations
32  */
33 
34 tnf_datum_t
35 tnf_get_file_header(TNF *tnf)
36 {
37 	return (DATUM(tnf->file_header_info, (caddr_t)tnf->file_header));
38 }
39 
40 /*
41  * Block access operations
42  */
43 
44 unsigned
45 tnf_get_block_count(TNF *tnf)
46 {
47 	return (tnf->block_count);
48 }
49 
50 tnf_datum_t
51 tnf_get_block_absolute(TNF *tnf, unsigned index)
52 {
53 	if (index >= tnf->block_count)
54 		/*
55 		 * access to non-existent block:
56 		 * no error as per spec
57 		 */
58 		return (TNF_DATUM_NULL);
59 	else
60 		/*
61 		 * XXX Require a single block header tag
62 		 */
63 		/* LINTED pointer cast may result in improper alignment */
64 		return (DATUM(tnf->block_header_info,
65 			    (caddr_t)_GET_INDEX_BLOCK(tnf, index)));
66 }
67 
68 tnf_datum_t
69 tnf_get_block_relative(tnf_datum_t datum, int adjust)
70 {
71 	TNF		*tnf;
72 	tnf_ref32_t	*bhdr;
73 	unsigned	index;
74 
75 	CHECK_DATUM(datum);
76 
77 	tnf 	= DATUM_TNF(datum);
78 	bhdr 	= _GET_BLOCK(tnf, DATUM_VAL(datum));
79 	index	= _GET_BLOCK_INDEX(tnf, bhdr);
80 
81 	return (tnf_get_block_absolute(tnf, index + adjust));
82 }
83 
84 int
85 tnf_is_block_header(tnf_datum_t datum)
86 {
87 	struct taginfo	*info;
88 	caddr_t		val;
89 	tnf_ref32_t	*bhdr;
90 
91 	CHECK_DATUM(datum);
92 
93 	info	= DATUM_INFO(datum);
94 	val	= DATUM_VAL(datum);
95 	bhdr	= _GET_BLOCK(info->tnf, val);
96 
97 	return (((caddr_t)bhdr == val) &&
98 		(info == info->tnf->block_header_info));
99 }
100 
101 tnf_datum_t
102 tnf_get_block_header(tnf_datum_t datum)
103 {
104 	TNF	*tnf;
105 	caddr_t	val;
106 
107 	CHECK_DATUM(datum);
108 
109 	tnf 	= DATUM_TNF(datum);
110 	val	= DATUM_VAL(datum);
111 	/*
112 	 * XXX Require a single block header tag
113 	 */
114 	return (DATUM(tnf->block_header_info, (caddr_t)_GET_BLOCK(tnf, val)));
115 }
116 
117 /*
118  * Sequential record access
119  */
120 
121 tnf_datum_t
122 tnf_get_next_record(tnf_datum_t datum)
123 {
124 	TNF		*tnf;
125 	tnf_ref32_t	*bhdr, *cell, ref32;
126 	caddr_t		val, nval, bval, blim;
127 	size_t		size, bytes;
128 
129 	CHECK_RECORD(datum);
130 
131 	tnf	= DATUM_TNF(datum);
132 	val	= DATUM_VAL(datum);
133 
134 	size	= tnf_get_size(datum);
135 	nval	= val + size;
136 
137 	/* Check file bounds */
138 	if (nval < tnf->data_start)
139 		return (tnf_get_block_absolute(tnf, 0));
140 	else if (nval >= tnf->file_end)
141 		return (TNF_DATUM_NULL);
142 
143 	/*
144 	 * OK, nval is in data area, start looking in block
145 	 */
146 	bhdr 	= _GET_BLOCK(tnf, nval);
147 	/* LINTED pointer cast may result in improper alignment */
148 	bytes	= _GET_BLOCK_BYTES_VALID(tnf, bhdr);
149 	bval 	= (caddr_t)bhdr;
150 	blim  	= bval + bytes;
151 
152 	/* sequentially examine valid cells in block from nval onwards */
153 	while (nval < blim) {
154 		/* LINTED pointer cast may result in improper alignment */
155 		cell 	= (tnf_ref32_t *)nval;
156 		ref32 	= _GET_INT32(tnf, cell);
157 
158 		switch (TNF_REF32_TYPE(ref32)) {
159 		case TNF_REF32_T_FWD: /* skip forwarding cells */
160 			nval += sizeof (tnf_ref32_t);
161 			break;
162 		case TNF_REF32_T_RSVD: /* catch bogus cells */
163 			_tnf_error(tnf, TNF_ERR_BADTNF);
164 			return (TNF_DATUM_NULL);
165 		default:	/* PAIR or TAG: record header */
166 			return (RECORD_DATUM(tnf, cell));
167 		}
168 	}
169 
170 	/*
171 	 * Couldn't find it: return next non-zero block header
172 	 */
173 	while ((bval += tnf->block_size) < tnf->file_end)
174 		/* Gotta check that there is a real bhdr here */
175 		/* LINTED pointer cast may result in improper alignment */
176 		if (*(tnf_ref32_t *)bval != TNF_NULL)
177 		/* LINTED pointer cast may result in improper alignment */
178 			return (RECORD_DATUM(tnf, (tnf_ref32_t *)bval));
179 
180 	/*
181 	 * default: we're off the end of the file
182 	 */
183 	return (TNF_DATUM_NULL);
184 }
185