1/*
2 *  linux/fs/isofs/dir.c
3 *
4 *  (C) 1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
5 *
6 *  (C) 1991  Linus Torvalds - minix filesystem
7 *
8 *  Steve Beynon		       : Missing last directory entries fixed
9 *  (stephen@askone.demon.co.uk)      : 21st June 1996
10 *
11 *  isofs directory handling functions
12 */
13#include <linux/smp_lock.h>
14#include <linux/gfp.h>
15#include "isofs.h"
16
17int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
18{
19	char * old = de->name;
20	int len = de->name_len[0];
21	int i;
22
23	for (i = 0; i < len; i++) {
24		unsigned char c = old[i];
25		if (!c)
26			break;
27
28		if (c >= 'A' && c <= 'Z')
29			c |= 0x20;	/* lower case */
30
31		/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
32		if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
33			break;
34
35		/* Drop trailing ';1' */
36		if (c == ';' && i == len - 2 && old[i + 1] == '1')
37			break;
38
39		/* Convert remaining ';' to '.' */
40		/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
41		if (c == ';' || c == '/')
42			c = '.';
43
44		new[i] = c;
45	}
46	return i;
47}
48
49/* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
50int get_acorn_filename(struct iso_directory_record *de,
51			    char *retname, struct inode *inode)
52{
53	int std;
54	unsigned char *chr;
55	int retnamlen = isofs_name_translate(de, retname, inode);
56
57	if (retnamlen == 0)
58		return 0;
59	std = sizeof(struct iso_directory_record) + de->name_len[0];
60	if (std & 1)
61		std++;
62	if ((*((unsigned char *) de) - std) != 32)
63		return retnamlen;
64	chr = ((unsigned char *) de) + std;
65	if (strncmp(chr, "ARCHIMEDES", 10))
66		return retnamlen;
67	if ((*retname == '_') && ((chr[19] & 1) == 1))
68		*retname = '!';
69	if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
70		&& ((chr[12] & 0xf0) == 0xf0)) {
71		retname[retnamlen] = ',';
72		sprintf(retname+retnamlen+1, "%3.3x",
73			((chr[12] & 0xf) << 8) | chr[11]);
74		retnamlen += 4;
75	}
76	return retnamlen;
77}
78
79/*
80 * This should _really_ be cleaned up some day..
81 */
82static int do_isofs_readdir(struct inode *inode, struct file *filp,
83		void *dirent, filldir_t filldir,
84		char *tmpname, struct iso_directory_record *tmpde)
85{
86	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
87	unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
88	unsigned long block, offset, block_saved, offset_saved;
89	unsigned long inode_number = 0;	/* Quiet GCC */
90	struct buffer_head *bh = NULL;
91	int len;
92	int map;
93	int first_de = 1;
94	char *p = NULL;		/* Quiet GCC */
95	struct iso_directory_record *de;
96	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
97
98	offset = filp->f_pos & (bufsize - 1);
99	block = filp->f_pos >> bufbits;
100
101	while (filp->f_pos < inode->i_size) {
102		int de_len;
103
104		if (!bh) {
105			bh = isofs_bread(inode, block);
106			if (!bh)
107				return 0;
108		}
109
110		de = (struct iso_directory_record *) (bh->b_data + offset);
111
112		de_len = *(unsigned char *) de;
113
114		/*
115		 * If the length byte is zero, we should move on to the next
116		 * CDROM sector.  If we are at the end of the directory, we
117		 * kick out of the while loop.
118		 */
119
120		if (de_len == 0) {
121			brelse(bh);
122			bh = NULL;
123			filp->f_pos = (filp->f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
124			block = filp->f_pos >> bufbits;
125			offset = 0;
126			continue;
127		}
128
129		block_saved = block;
130		offset_saved = offset;
131		offset += de_len;
132
133		/* Make sure we have a full directory entry */
134		if (offset >= bufsize) {
135			int slop = bufsize - offset + de_len;
136			memcpy(tmpde, de, slop);
137			offset &= bufsize - 1;
138			block++;
139			brelse(bh);
140			bh = NULL;
141			if (offset) {
142				bh = isofs_bread(inode, block);
143				if (!bh)
144					return 0;
145				memcpy((void *) tmpde + slop, bh->b_data, offset);
146			}
147			de = tmpde;
148		}
149		/* Basic sanity check, whether name doesn't exceed dir entry */
150		if (de_len < de->name_len[0] +
151					sizeof(struct iso_directory_record)) {
152			printk(KERN_NOTICE "iso9660: Corrupted directory entry"
153			       " in block %lu of inode %lu\n", block,
154			       inode->i_ino);
155			return -EIO;
156		}
157
158		if (first_de) {
159			isofs_normalize_block_and_offset(de,
160							&block_saved,
161							&offset_saved);
162			inode_number = isofs_get_ino(block_saved,
163							offset_saved, bufbits);
164		}
165
166		if (de->flags[-sbi->s_high_sierra] & 0x80) {
167			first_de = 0;
168			filp->f_pos += de_len;
169			continue;
170		}
171		first_de = 1;
172
173		/* Handle the case of the '.' directory */
174		if (de->name_len[0] == 1 && de->name[0] == 0) {
175			if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino, DT_DIR) < 0)
176				break;
177			filp->f_pos += de_len;
178			continue;
179		}
180
181		len = 0;
182
183		/* Handle the case of the '..' directory */
184		if (de->name_len[0] == 1 && de->name[0] == 1) {
185			inode_number = parent_ino(filp->f_path.dentry);
186			if (filldir(dirent, "..", 2, filp->f_pos, inode_number, DT_DIR) < 0)
187				break;
188			filp->f_pos += de_len;
189			continue;
190		}
191
192		/* Handle everything else.  Do name translation if there
193		   is no Rock Ridge NM field. */
194
195		/*
196		 * Do not report hidden files if so instructed, or associated
197		 * files unless instructed to do so
198		 */
199		if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
200		    (!sbi->s_showassoc &&
201				(de->flags[-sbi->s_high_sierra] & 4))) {
202			filp->f_pos += de_len;
203			continue;
204		}
205
206		map = 1;
207		if (sbi->s_rock) {
208			len = get_rock_ridge_filename(de, tmpname, inode);
209			if (len != 0) {		/* may be -1 */
210				p = tmpname;
211				map = 0;
212			}
213		}
214		if (map) {
215#ifdef CONFIG_JOLIET
216			if (sbi->s_joliet_level) {
217				len = get_joliet_filename(de, tmpname, inode);
218				p = tmpname;
219			} else
220#endif
221			if (sbi->s_mapping == 'a') {
222				len = get_acorn_filename(de, tmpname, inode);
223				p = tmpname;
224			} else
225			if (sbi->s_mapping == 'n') {
226				len = isofs_name_translate(de, tmpname, inode);
227				p = tmpname;
228			} else {
229				p = de->name;
230				len = de->name_len[0];
231			}
232		}
233		if (len > 0) {
234			if (filldir(dirent, p, len, filp->f_pos, inode_number, DT_UNKNOWN) < 0)
235				break;
236		}
237		filp->f_pos += de_len;
238
239		continue;
240	}
241	if (bh)
242		brelse(bh);
243	return 0;
244}
245
246/*
247 * Handle allocation of temporary space for name translation and
248 * handling split directory entries.. The real work is done by
249 * "do_isofs_readdir()".
250 */
251static int isofs_readdir(struct file *filp,
252		void *dirent, filldir_t filldir)
253{
254	int result;
255	char *tmpname;
256	struct iso_directory_record *tmpde;
257	struct inode *inode = filp->f_path.dentry->d_inode;
258
259	tmpname = (char *)__get_free_page(GFP_KERNEL);
260	if (tmpname == NULL)
261		return -ENOMEM;
262
263	lock_kernel();
264	tmpde = (struct iso_directory_record *) (tmpname+1024);
265
266	result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
267
268	free_page((unsigned long) tmpname);
269	unlock_kernel();
270	return result;
271}
272
273const struct file_operations isofs_dir_operations =
274{
275	.llseek = generic_file_llseek,
276	.read = generic_read_dir,
277	.readdir = isofs_readdir,
278};
279
280/*
281 * directories can handle most operations...
282 */
283const struct inode_operations isofs_dir_inode_operations =
284{
285	.lookup = isofs_lookup,
286};
287