xref: /openbmc/linux/fs/isofs/dir.c (revision 95e9fd10)
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/gfp.h>
14 #include "isofs.h"
15 
16 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
17 {
18 	char * old = de->name;
19 	int len = de->name_len[0];
20 	int i;
21 
22 	for (i = 0; i < len; i++) {
23 		unsigned char c = old[i];
24 		if (!c)
25 			break;
26 
27 		if (c >= 'A' && c <= 'Z')
28 			c |= 0x20;	/* lower case */
29 
30 		/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
31 		if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
32 			break;
33 
34 		/* Drop trailing ';1' */
35 		if (c == ';' && i == len - 2 && old[i + 1] == '1')
36 			break;
37 
38 		/* Convert remaining ';' to '.' */
39 		/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
40 		if (c == ';' || c == '/')
41 			c = '.';
42 
43 		new[i] = c;
44 	}
45 	return i;
46 }
47 
48 /* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
49 int get_acorn_filename(struct iso_directory_record *de,
50 			    char *retname, struct inode *inode)
51 {
52 	int std;
53 	unsigned char *chr;
54 	int retnamlen = isofs_name_translate(de, retname, inode);
55 
56 	if (retnamlen == 0)
57 		return 0;
58 	std = sizeof(struct iso_directory_record) + de->name_len[0];
59 	if (std & 1)
60 		std++;
61 	if ((*((unsigned char *) de) - std) != 32)
62 		return retnamlen;
63 	chr = ((unsigned char *) de) + std;
64 	if (strncmp(chr, "ARCHIMEDES", 10))
65 		return retnamlen;
66 	if ((*retname == '_') && ((chr[19] & 1) == 1))
67 		*retname = '!';
68 	if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
69 		&& ((chr[12] & 0xf0) == 0xf0)) {
70 		retname[retnamlen] = ',';
71 		sprintf(retname+retnamlen+1, "%3.3x",
72 			((chr[12] & 0xf) << 8) | chr[11]);
73 		retnamlen += 4;
74 	}
75 	return retnamlen;
76 }
77 
78 /*
79  * This should _really_ be cleaned up some day..
80  */
81 static int do_isofs_readdir(struct inode *inode, struct file *filp,
82 		void *dirent, filldir_t filldir,
83 		char *tmpname, struct iso_directory_record *tmpde)
84 {
85 	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
86 	unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
87 	unsigned long block, offset, block_saved, offset_saved;
88 	unsigned long inode_number = 0;	/* Quiet GCC */
89 	struct buffer_head *bh = NULL;
90 	int len;
91 	int map;
92 	int first_de = 1;
93 	char *p = NULL;		/* Quiet GCC */
94 	struct iso_directory_record *de;
95 	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
96 
97 	offset = filp->f_pos & (bufsize - 1);
98 	block = filp->f_pos >> bufbits;
99 
100 	while (filp->f_pos < inode->i_size) {
101 		int de_len;
102 
103 		if (!bh) {
104 			bh = isofs_bread(inode, block);
105 			if (!bh)
106 				return 0;
107 		}
108 
109 		de = (struct iso_directory_record *) (bh->b_data + offset);
110 
111 		de_len = *(unsigned char *) de;
112 
113 		/*
114 		 * If the length byte is zero, we should move on to the next
115 		 * CDROM sector.  If we are at the end of the directory, we
116 		 * kick out of the while loop.
117 		 */
118 
119 		if (de_len == 0) {
120 			brelse(bh);
121 			bh = NULL;
122 			filp->f_pos = (filp->f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
123 			block = filp->f_pos >> bufbits;
124 			offset = 0;
125 			continue;
126 		}
127 
128 		block_saved = block;
129 		offset_saved = offset;
130 		offset += de_len;
131 
132 		/* Make sure we have a full directory entry */
133 		if (offset >= bufsize) {
134 			int slop = bufsize - offset + de_len;
135 			memcpy(tmpde, de, slop);
136 			offset &= bufsize - 1;
137 			block++;
138 			brelse(bh);
139 			bh = NULL;
140 			if (offset) {
141 				bh = isofs_bread(inode, block);
142 				if (!bh)
143 					return 0;
144 				memcpy((void *) tmpde + slop, bh->b_data, offset);
145 			}
146 			de = tmpde;
147 		}
148 		/* Basic sanity check, whether name doesn't exceed dir entry */
149 		if (de_len < de->name_len[0] +
150 					sizeof(struct iso_directory_record)) {
151 			printk(KERN_NOTICE "iso9660: Corrupted directory entry"
152 			       " in block %lu of inode %lu\n", block,
153 			       inode->i_ino);
154 			return -EIO;
155 		}
156 
157 		if (first_de) {
158 			isofs_normalize_block_and_offset(de,
159 							&block_saved,
160 							&offset_saved);
161 			inode_number = isofs_get_ino(block_saved,
162 							offset_saved, bufbits);
163 		}
164 
165 		if (de->flags[-sbi->s_high_sierra] & 0x80) {
166 			first_de = 0;
167 			filp->f_pos += de_len;
168 			continue;
169 		}
170 		first_de = 1;
171 
172 		/* Handle the case of the '.' directory */
173 		if (de->name_len[0] == 1 && de->name[0] == 0) {
174 			if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino, DT_DIR) < 0)
175 				break;
176 			filp->f_pos += de_len;
177 			continue;
178 		}
179 
180 		len = 0;
181 
182 		/* Handle the case of the '..' directory */
183 		if (de->name_len[0] == 1 && de->name[0] == 1) {
184 			inode_number = parent_ino(filp->f_path.dentry);
185 			if (filldir(dirent, "..", 2, filp->f_pos, inode_number, DT_DIR) < 0)
186 				break;
187 			filp->f_pos += de_len;
188 			continue;
189 		}
190 
191 		/* Handle everything else.  Do name translation if there
192 		   is no Rock Ridge NM field. */
193 
194 		/*
195 		 * Do not report hidden files if so instructed, or associated
196 		 * files unless instructed to do so
197 		 */
198 		if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
199 		    (!sbi->s_showassoc &&
200 				(de->flags[-sbi->s_high_sierra] & 4))) {
201 			filp->f_pos += de_len;
202 			continue;
203 		}
204 
205 		map = 1;
206 		if (sbi->s_rock) {
207 			len = get_rock_ridge_filename(de, tmpname, inode);
208 			if (len != 0) {		/* may be -1 */
209 				p = tmpname;
210 				map = 0;
211 			}
212 		}
213 		if (map) {
214 #ifdef CONFIG_JOLIET
215 			if (sbi->s_joliet_level) {
216 				len = get_joliet_filename(de, tmpname, inode);
217 				p = tmpname;
218 			} else
219 #endif
220 			if (sbi->s_mapping == 'a') {
221 				len = get_acorn_filename(de, tmpname, inode);
222 				p = tmpname;
223 			} else
224 			if (sbi->s_mapping == 'n') {
225 				len = isofs_name_translate(de, tmpname, inode);
226 				p = tmpname;
227 			} else {
228 				p = de->name;
229 				len = de->name_len[0];
230 			}
231 		}
232 		if (len > 0) {
233 			if (filldir(dirent, p, len, filp->f_pos, inode_number, DT_UNKNOWN) < 0)
234 				break;
235 		}
236 		filp->f_pos += de_len;
237 
238 		continue;
239 	}
240 	if (bh)
241 		brelse(bh);
242 	return 0;
243 }
244 
245 /*
246  * Handle allocation of temporary space for name translation and
247  * handling split directory entries.. The real work is done by
248  * "do_isofs_readdir()".
249  */
250 static int isofs_readdir(struct file *filp,
251 		void *dirent, filldir_t filldir)
252 {
253 	int result;
254 	char *tmpname;
255 	struct iso_directory_record *tmpde;
256 	struct inode *inode = filp->f_path.dentry->d_inode;
257 
258 	tmpname = (char *)__get_free_page(GFP_KERNEL);
259 	if (tmpname == NULL)
260 		return -ENOMEM;
261 
262 	tmpde = (struct iso_directory_record *) (tmpname+1024);
263 
264 	result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
265 
266 	free_page((unsigned long) tmpname);
267 	return result;
268 }
269 
270 const struct file_operations isofs_dir_operations =
271 {
272 	.llseek = generic_file_llseek,
273 	.read = generic_read_dir,
274 	.readdir = isofs_readdir,
275 };
276 
277 /*
278  * directories can handle most operations...
279  */
280 const struct inode_operations isofs_dir_inode_operations =
281 {
282 	.lookup = isofs_lookup,
283 };
284 
285 
286