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*/
1 /*
2 * linux/fs/isofs/dir.c
3 *
4 * (C) 1992 Eric Youngdale Modified for ISO9660 filesystem.
5 *
6 * (C) 1991 Linus Torvalds - minix filesystem
7 *
8 * isofs directory handling functions
9 */
10
11 #include <linux/errno.h>
12
13 #include <asm/segment.h>
14
15 #include <linux/fs.h>
16 #include <linux/iso_fs.h>
17 #include <linux/kernel.h>
18 #include <linux/stat.h>
19 #include <linux/string.h>
20 #include <linux/mm.h>
21
22 static int isofs_readdir(struct inode *, struct file *, struct dirent *, int);
23
24 static struct file_operations isofs_dir_operations = {
25 NULL, /* lseek - default */
26 NULL, /* read */
27 NULL, /* write - bad */
28 isofs_readdir, /* readdir */
29 NULL, /* select - default */
30 NULL, /* ioctl - default */
31 NULL, /* no special open code */
32 NULL /* no special release code */
33 };
34
35 /*
36 * directories can handle most operations...
37 */
38 struct inode_operations isofs_dir_inode_operations = {
39 &isofs_dir_operations, /* default directory file-ops */
40 NULL, /* create */
41 isofs_lookup, /* lookup */
42 NULL, /* link */
43 NULL, /* unlink */
44 NULL, /* symlink */
45 NULL, /* mkdir */
46 NULL, /* rmdir */
47 NULL, /* mknod */
48 NULL, /* rename */
49 NULL, /* readlink */
50 NULL, /* follow_link */
51 isofs_bmap, /* bmap */
52 NULL, /* truncate */
53 NULL /* permission */
54 };
55
56 /* This is used to speed up lookup. Without this we would need to
57 make a linear search of the directory to find the file that the
58 directory read just returned. This is a single element cache. */
59
60 struct lookup_cache cache = {0,};
61
62 static int isofs_readdir(struct inode * inode, struct file * filp,
/* ![[first]](../icons/n_first.png)
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*/
63 struct dirent * dirent, int count)
64 {
65 unsigned int block,offset,i, j;
66 char c = 0;
67 int inode_number;
68 struct buffer_head * bh;
69 char * cpnt = 0;
70 unsigned int old_offset;
71 int dlen, rrflag;
72 char * dpnt;
73 struct iso_directory_record * de;
74
75 if (!inode || !S_ISDIR(inode->i_mode))
76 return -EBADF;
77
78 offset = filp->f_pos & (BLOCK_SIZE - 1);
79 block = isofs_bmap(inode,(filp->f_pos)>>BLOCK_SIZE_BITS);
80 if (!block || !(bh = bread(inode->i_dev,block,ISOFS_BUFFER_SIZE)))
81 return 0;
82
83 while (filp->f_pos < inode->i_size) {
84 #ifdef DEBUG
85 printk("Block, offset: %x %x %x\n",block, offset, filp->f_pos);
86 #endif
87 de = (struct iso_directory_record *) (offset + bh->b_data);
88 inode_number = (block << BLOCK_SIZE_BITS)+(offset & (BLOCK_SIZE - 1));
89
90 /* If the length byte is zero, we should move on to the next CDROM sector.
91 If we are at the end of the directory, we kick out of the while loop. */
92
93 if (*((char*) de) == 0) {
94 brelse(bh);
95 offset = 0;
96 filp->f_pos =(filp->f_pos & ~(ISOFS_BLOCK_SIZE - 1))+ISOFS_BLOCK_SIZE;
97 block = isofs_bmap(inode,(filp->f_pos)>>BLOCK_SIZE_BITS);
98 if (!block || !(bh = bread(inode->i_dev,block,ISOFS_BUFFER_SIZE)))
99 return 0;
100 continue;
101 }
102
103 /* Make sure that the entire directory record is in the current bh block.
104 If not, we malloc a buffer, and put the two halves together, so that
105 we can cleanly read the block */
106
107 old_offset = offset;
108 offset += *((unsigned char*) de);
109 filp->f_pos += *((unsigned char*) de);
110 if (offset >= BLOCK_SIZE) {
111 cpnt = kmalloc(1 << ISOFS_BLOCK_BITS, GFP_KERNEL);
112 memcpy(cpnt, bh->b_data, BLOCK_SIZE);
113 de = (struct iso_directory_record *) (old_offset + cpnt);
114 brelse(bh);
115 offset = filp->f_pos & (BLOCK_SIZE - 1);
116 block = isofs_bmap(inode,(filp->f_pos)>>BLOCK_SIZE_BITS);
117 if (!block || !(bh = bread(inode->i_dev,block,ISOFS_BUFFER_SIZE)))
118 return 0;
119 memcpy(cpnt+BLOCK_SIZE, bh->b_data, BLOCK_SIZE);
120 }
121
122 /* Handle the case of the '.' directory */
123
124 rrflag = 0;
125 i = 1;
126 if (de->name_len[0] == 1 && de->name[0] == 0) {
127 put_fs_byte('.',dirent->d_name);
128 inode_number = inode->i_ino;
129 dpnt = ".";
130 }
131
132 /* Handle the case of the '..' directory */
133
134 else if (de->name_len[0] == 1 && de->name[0] == 1) {
135 put_fs_byte('.',dirent->d_name);
136 put_fs_byte('.',dirent->d_name+1);
137 i = 2;
138 dpnt = "..";
139 if((inode->i_sb->u.isofs_sb.s_firstdatazone << BLOCK_SIZE_BITS) != inode->i_ino)
140 inode_number = inode->u.isofs_i.i_backlink;
141 else
142 inode_number = inode->i_ino;
143
144 /* This should never happen, but who knows. Try to be forgiving */
145 if(inode_number == -1) {
146 inode_number =
147 isofs_lookup_grandparent(inode,
148 find_rock_ridge_relocation(de, inode));
149 if(inode_number == -1){ /* Should never happen */
150 printk("Backlink not properly set.\n");
151 goto out;
152 };
153 }
154 }
155
156 /* Handle everything else. Do name translation if there
157 is no Rock Ridge NM field. */
158
159 else {
160 dlen = de->name_len[0];
161 dpnt = de->name;
162 i = dlen;
163 rrflag = get_rock_ridge_filename(de, &dpnt, &dlen, inode);
164 if (rrflag) {
165 if (rrflag == -1) { /* This is a rock ridge reloc dir */
166 if (cpnt) {
167 kfree_s(cpnt, 1 << ISOFS_BLOCK_BITS);
168 cpnt = 0;
169 };
170 continue;
171 };
172 i = dlen;
173 }
174 else
175 if(inode->i_sb->u.isofs_sb.s_mapping == 'n')
176 for (i = 0; i < dlen && i < NAME_MAX; i++) {
177 if (!(c = dpnt[i])) break;
178 if (c >= 'A' && c <= 'Z') c |= 0x20; /* lower case */
179 if (c == ';' && i == dlen-2 && de->name[i+1] == '1')
180 break; /* Drop trailing ';1' */
181 if (c == ';') c = '.'; /* Convert remaining ';' to '.' */
182 dpnt[i] = c;
183 };
184
185 for(j=0; j<i; j++)
186 put_fs_byte(dpnt[j],j+dirent->d_name); /* And save it */
187 };
188 #if 0
189 printk("Nchar: %d\n",i);
190 #endif
191
192 if (i) {
193 while (cache.lock);
194 cache.lock = 1;
195 cache.ino = inode_number;
196 cache.dir = inode->i_ino;
197 cache.dev = inode->i_dev;
198 strncpy(cache.filename, dpnt, i);
199 cache.dlen = dlen;
200 cache.lock = 0;
201 };
202
203 if (rrflag) kfree(dpnt);
204 if (cpnt) {
205 kfree_s(cpnt, 1 << ISOFS_BLOCK_BITS);
206 cpnt = 0;
207 };
208
209 if (i) {
210 put_fs_long(inode_number, &dirent->d_ino);
211 put_fs_byte(0,i+dirent->d_name);
212 put_fs_word(i,&dirent->d_reclen);
213 brelse(bh);
214 return i;
215 }
216 }
217 /* We go here for any condition we cannot handle. We also drop through
218 to here at the end of the directory. */
219 out:
220 if (cpnt) kfree_s(cpnt, 1 << ISOFS_BLOCK_BITS);
221 brelse(bh);
222 return 0;
223 }
224
225
226
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*/