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#include <linux/smp_lock.h>
34#include <linux/buffer_head.h>
35
36#include "udf_i.h"
37#include "udf_sb.h"
38
39/* Prototypes for file operations */
40static int udf_readdir(struct file *, void *, filldir_t);
41static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
42
43/* readdir and lookup functions */
44
45const struct file_operations udf_dir_operations = {
46	.read			= generic_read_dir,
47	.readdir		= udf_readdir,
48	.ioctl			= udf_ioctl,
49	.fsync			= udf_fsync_file,
50};
51
52/*
53 * udf_readdir
54 *
55 * PURPOSE
56 *	Read a directory entry.
57 *
58 * DESCRIPTION
59 *	Optional - sys_getdents() will return -ENOTDIR if this routine is not
60 *	available.
61 *
62 *	Refer to sys_getdents() in fs/readdir.c
63 *	sys_getdents() -> .
64 *
65 * PRE-CONDITIONS
66 *	filp			Pointer to directory file.
67 *	buf			Pointer to directory entry buffer.
68 *	filldir			Pointer to filldir function.
69 *
70 * POST-CONDITIONS
71 *	<return>		>=0 on success.
72 *
73 * HISTORY
74 *	July 1, 1997 - Andrew E. Mileski
75 *	Written, tested, and released.
76 */
77
78int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
79{
80	struct inode *dir = filp->f_path.dentry->d_inode;
81	int result;
82
83	lock_kernel();
84
85	if ( filp->f_pos == 0 )
86	{
87		if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0)
88		{
89			unlock_kernel();
90			return 0;
91		}
92		filp->f_pos ++;
93	}
94
95	result = do_udf_readdir(dir, filp, filldir, dirent);
96	unlock_kernel();
97 	return result;
98}
99
100static int
101do_udf_readdir(struct inode * dir, struct file *filp, filldir_t filldir, void *dirent)
102{
103	struct udf_fileident_bh fibh;
104	struct fileIdentDesc *fi=NULL;
105	struct fileIdentDesc cfi;
106	int block, iblock;
107	loff_t nf_pos = filp->f_pos - 1;
108	int flen;
109	char fname[UDF_NAME_LEN];
110	char *nameptr;
111	uint16_t liu;
112	uint8_t lfi;
113	loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
114	struct buffer_head *tmp, *bha[16];
115	kernel_lb_addr eloc;
116	uint32_t elen;
117	sector_t offset;
118	int i, num;
119	unsigned int dt_type;
120	struct extent_position epos = { NULL, 0, {0, 0}};
121
122	if (nf_pos >= size)
123		return 0;
124
125	if (nf_pos == 0)
126		nf_pos = (udf_ext0_offset(dir) >> 2);
127
128	fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
129	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
130		fibh.sbh = fibh.ebh = NULL;
131	else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
132		&epos, &eloc, &elen, &offset) == (EXT_RECORDED_ALLOCATED >> 30))
133	{
134		block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
135		if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
136		{
137			if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
138				epos.offset -= sizeof(short_ad);
139			else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
140				epos.offset -= sizeof(long_ad);
141		}
142		else
143			offset = 0;
144
145		if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
146		{
147			brelse(epos.bh);
148			return -EIO;
149		}
150
151		if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9))-1)))
152		{
153			i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
154			if (i+offset > (elen >> dir->i_sb->s_blocksize_bits))
155				i = (elen >> dir->i_sb->s_blocksize_bits)-offset;
156			for (num=0; i>0; i--)
157			{
158				block = udf_get_lb_pblock(dir->i_sb, eloc, offset+i);
159				tmp = udf_tgetblk(dir->i_sb, block);
160				if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
161					bha[num++] = tmp;
162				else
163					brelse(tmp);
164			}
165			if (num)
166			{
167				ll_rw_block(READA, num, bha);
168				for (i=0; i<num; i++)
169					brelse(bha[i]);
170			}
171		}
172	}
173	else
174	{
175		brelse(epos.bh);
176		return -ENOENT;
177	}
178
179	while ( nf_pos < size )
180	{
181		filp->f_pos = nf_pos + 1;
182
183		fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc, &elen, &offset);
184
185		if (!fi)
186		{
187			if (fibh.sbh != fibh.ebh)
188				brelse(fibh.ebh);
189			brelse(fibh.sbh);
190			brelse(epos.bh);
191			return 0;
192		}
193
194		liu = le16_to_cpu(cfi.lengthOfImpUse);
195		lfi = cfi.lengthFileIdent;
196
197		if (fibh.sbh == fibh.ebh)
198			nameptr = fi->fileIdent + liu;
199		else
200		{
201			int poffset;	/* Unpaded ending offset */
202
203			poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
204
205			if (poffset >= lfi)
206				nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
207			else
208			{
209				nameptr = fname;
210				memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
211				memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
212			}
213		}
214
215		if ( (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0 )
216		{
217			if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
218				continue;
219		}
220
221		if ( (cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0 )
222		{
223			if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
224				continue;
225		}
226
227		if ( cfi.fileCharacteristics & FID_FILE_CHAR_PARENT )
228		{
229			iblock = parent_ino(filp->f_path.dentry);
230			flen = 2;
231			memcpy(fname, "..", flen);
232			dt_type = DT_DIR;
233		}
234		else
235		{
236			kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
237
238			iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
239			flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
240			dt_type = DT_UNKNOWN;
241		}
242
243		if (flen)
244		{
245			if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0)
246			{
247				if (fibh.sbh != fibh.ebh)
248					brelse(fibh.ebh);
249				brelse(fibh.sbh);
250				brelse(epos.bh);
251	 			return 0;
252			}
253		}
254	} /* end while */
255
256	filp->f_pos = nf_pos + 1;
257
258	if (fibh.sbh != fibh.ebh)
259		brelse(fibh.ebh);
260	brelse(fibh.sbh);
261	brelse(epos.bh);
262
263	return 0;
264}
265