1/*
2 * dir.c
3 *
4 * PURPOSE
5 *  Directory handling routines for the OSTA-UDF(tm) filesystem.
6 *
7 * COPYRIGHT
8 *	This file is distributed under the terms of the GNU General Public
9 *	License (GPL). Copies of the GPL can be obtained from:
10 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
11 *	Each contributing author retains all rights to their own work.
12 *
13 *  (C) 1998-2004 Ben Fennema
14 *
15 * HISTORY
16 *
17 *  10/05/98 dgb  Split directory operations into its own file
18 *                Implemented directory reads via do_udf_readdir
19 *  10/06/98      Made directory operations work!
20 *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
21 *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
22 *                across blocks.
23 *  12/12/98      Split out the lookup code to namei.c. bulk of directory
24 *                code now in directory.c:udf_fileident_read.
25 */
26
27#include "udfdecl.h"
28
29#include <linux/string.h>
30#include <linux/errno.h>
31#include <linux/mm.h>
32#include <linux/slab.h>
33
34#include "udf_i.h"
35#include "udf_sb.h"
36
37
38static int udf_readdir(struct file *file, struct dir_context *ctx)
39{
40	struct inode *dir = file_inode(file);
41	struct udf_inode_info *iinfo = UDF_I(dir);
42	struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
43	struct fileIdentDesc *fi = NULL;
44	struct fileIdentDesc cfi;
45	int block, iblock;
46	loff_t nf_pos;
47	int flen;
48	unsigned char *fname = NULL;
49	unsigned char *nameptr;
50	uint16_t liu;
51	uint8_t lfi;
52	loff_t size = udf_ext0_offset(dir) + dir->i_size;
53	struct buffer_head *tmp, *bha[16];
54	struct kernel_lb_addr eloc;
55	uint32_t elen;
56	sector_t offset;
57	int i, num, ret = 0;
58	struct extent_position epos = { NULL, 0, {0, 0} };
59	struct super_block *sb = dir->i_sb;
60
61	if (ctx->pos == 0) {
62		if (!dir_emit_dot(file, ctx))
63			return 0;
64		ctx->pos = 1;
65	}
66	nf_pos = (ctx->pos - 1) << 2;
67	if (nf_pos >= size)
68		goto out;
69
70	fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
71	if (!fname) {
72		ret = -ENOMEM;
73		goto out;
74	}
75
76	if (nf_pos == 0)
77		nf_pos = udf_ext0_offset(dir);
78
79	fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
80	if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
81		if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
82		    &epos, &eloc, &elen, &offset)
83		    != (EXT_RECORDED_ALLOCATED >> 30)) {
84			ret = -ENOENT;
85			goto out;
86		}
87		block = udf_get_lb_pblock(sb, &eloc, offset);
88		if ((++offset << sb->s_blocksize_bits) < elen) {
89			if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
90				epos.offset -= sizeof(struct short_ad);
91			else if (iinfo->i_alloc_type ==
92					ICBTAG_FLAG_AD_LONG)
93				epos.offset -= sizeof(struct long_ad);
94		} else {
95			offset = 0;
96		}
97
98		if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
99			ret = -EIO;
100			goto out;
101		}
102
103		if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
104			i = 16 >> (sb->s_blocksize_bits - 9);
105			if (i + offset > (elen >> sb->s_blocksize_bits))
106				i = (elen >> sb->s_blocksize_bits) - offset;
107			for (num = 0; i > 0; i--) {
108				block = udf_get_lb_pblock(sb, &eloc, offset + i);
109				tmp = udf_tgetblk(sb, block);
110				if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
111					bha[num++] = tmp;
112				else
113					brelse(tmp);
114			}
115			if (num) {
116				ll_rw_block(READA, num, bha);
117				for (i = 0; i < num; i++)
118					brelse(bha[i]);
119			}
120		}
121	}
122
123	while (nf_pos < size) {
124		struct kernel_lb_addr tloc;
125
126		ctx->pos = (nf_pos >> 2) + 1;
127
128		fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
129					&elen, &offset);
130		if (!fi)
131			goto out;
132
133		liu = le16_to_cpu(cfi.lengthOfImpUse);
134		lfi = cfi.lengthFileIdent;
135
136		if (fibh.sbh == fibh.ebh) {
137			nameptr = fi->fileIdent + liu;
138		} else {
139			int poffset;	/* Unpaded ending offset */
140
141			poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
142
143			if (poffset >= lfi) {
144				nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
145			} else {
146				nameptr = fname;
147				memcpy(nameptr, fi->fileIdent + liu,
148				       lfi - poffset);
149				memcpy(nameptr + lfi - poffset,
150				       fibh.ebh->b_data, poffset);
151			}
152		}
153
154		if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
155			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
156				continue;
157		}
158
159		if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
160			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
161				continue;
162		}
163
164		if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
165			if (!dir_emit_dotdot(file, ctx))
166				goto out;
167			continue;
168		}
169
170		flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
171		if (!flen)
172			continue;
173
174		tloc = lelb_to_cpu(cfi.icb.extLocation);
175		iblock = udf_get_lb_pblock(sb, &tloc, 0);
176		if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
177			goto out;
178	} /* end while */
179
180	ctx->pos = (nf_pos >> 2) + 1;
181
182out:
183	if (fibh.sbh != fibh.ebh)
184		brelse(fibh.ebh);
185	brelse(fibh.sbh);
186	brelse(epos.bh);
187	kfree(fname);
188
189	return ret;
190}
191
192/* readdir and lookup functions */
193const struct file_operations udf_dir_operations = {
194	.llseek			= generic_file_llseek,
195	.read			= generic_read_dir,
196	.iterate		= udf_readdir,
197	.unlocked_ioctl		= udf_ioctl,
198	.fsync			= generic_file_fsync,
199};
200