xref: /openbmc/linux/fs/udf/dir.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 */
40 static int udf_readdir(struct file *, void *, filldir_t);
41 static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
42 
43 /* readdir and lookup functions */
44 
45 const 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 
78 int 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 
100 static int
101 do_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