Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 "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 
149                 if (first_de) {
150                         isofs_normalize_block_and_offset(de,
151                                                         &block_saved,
152                                                         &offset_saved);
153                         inode_number = isofs_get_ino(block_saved,
154                                                         offset_saved, bufbits);
155                 }
156 
157                 if (de->flags[-sbi->s_high_sierra] & 0x80) {
158                         first_de = 0;
159                         filp->f_pos += de_len;
160                         continue;
161                 }
162                 first_de = 1;
163 
164                 /* Handle the case of the '.' directory */
165                 if (de->name_len[0] == 1 && de->name[0] == 0) {
166                         if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino, DT_DIR) < 0)
167                                 break;
168                         filp->f_pos += de_len;
169                         continue;
170                 }
171 
172                 len = 0;
173 
174                 /* Handle the case of the '..' directory */
175                 if (de->name_len[0] == 1 && de->name[0] == 1) {
176                         inode_number = parent_ino(filp->f_path.dentry);
177                         if (filldir(dirent, "..", 2, filp->f_pos, inode_number, DT_DIR) < 0)
178                                 break;
179                         filp->f_pos += de_len;
180                         continue;
181                 }
182 
183                 /* Handle everything else.  Do name translation if there
184                    is no Rock Ridge NM field. */
185 
186                 /*
187                  * Do not report hidden files if so instructed, or associated
188                  * files unless instructed to do so
189                  */
190                 if ((sbi->s_hide == 'y' &&
191                                 (de->flags[-sbi->s_high_sierra] & 1)) ||
192                                 (sbi->s_showassoc =='n' &&
193                                 (de->flags[-sbi->s_high_sierra] & 4))) {
194                         filp->f_pos += de_len;
195                         continue;
196                 }
197 
198                 map = 1;
199                 if (sbi->s_rock) {
200                         len = get_rock_ridge_filename(de, tmpname, inode);
201                         if (len != 0) {         /* may be -1 */
202                                 p = tmpname;
203                                 map = 0;
204                         }
205                 }
206                 if (map) {
207 #ifdef CONFIG_JOLIET
208                         if (sbi->s_joliet_level) {
209                                 len = get_joliet_filename(de, tmpname, inode);
210                                 p = tmpname;
211                         } else
212 #endif
213                         if (sbi->s_mapping == 'a') {
214                                 len = get_acorn_filename(de, tmpname, inode);
215                                 p = tmpname;
216                         } else
217                         if (sbi->s_mapping == 'n') {
218                                 len = isofs_name_translate(de, tmpname, inode);
219                                 p = tmpname;
220                         } else {
221                                 p = de->name;
222                                 len = de->name_len[0];
223                         }
224                 }
225                 if (len > 0) {
226                         if (filldir(dirent, p, len, filp->f_pos, inode_number, DT_UNKNOWN) < 0)
227                                 break;
228                 }
229                 filp->f_pos += de_len;
230 
231                 continue;
232         }
233         if (bh)
234                 brelse(bh);
235         return 0;
236 }
237 
238 /*
239  * Handle allocation of temporary space for name translation and
240  * handling split directory entries.. The real work is done by
241  * "do_isofs_readdir()".
242  */
243 static int isofs_readdir(struct file *filp,
244                 void *dirent, filldir_t filldir)
245 {
246         int result;
247         char *tmpname;
248         struct iso_directory_record *tmpde;
249         struct inode *inode = filp->f_path.dentry->d_inode;
250 
251         tmpname = (char *)__get_free_page(GFP_KERNEL);
252         if (tmpname == NULL)
253                 return -ENOMEM;
254 
255         lock_kernel();
256         tmpde = (struct iso_directory_record *) (tmpname+1024);
257 
258         result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
259 
260         free_page((unsigned long) tmpname);
261         unlock_kernel();
262         return result;
263 }
264 
265 const struct file_operations isofs_dir_operations =
266 {
267         .read = generic_read_dir,
268         .readdir = isofs_readdir,
269 };
270 
271 /*
272  * directories can handle most operations...
273  */
274 const struct inode_operations isofs_dir_inode_operations =
275 {
276         .lookup = isofs_lookup,
277 };
278 
279 
280 
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