1 /* 2 * linux/fs/isofs/namei.c 3 * 4 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. 5 * 6 * (C) 1991 Linus Torvalds - minix filesystem 7 */ 8 9 #include <linux/config.h> /* Joliet? */ 10 #include <linux/smp_lock.h> 11 #include "isofs.h" 12 13 /* 14 * ok, we cannot use strncmp, as the name is not in our data space. 15 * Thus we'll have to use isofs_match. No big problem. Match also makes 16 * some sanity tests. 17 */ 18 static int 19 isofs_cmp(struct dentry * dentry, const char * compare, int dlen) 20 { 21 struct qstr qstr; 22 23 if (!compare) 24 return 1; 25 26 /* check special "." and ".." files */ 27 if (dlen == 1) { 28 /* "." */ 29 if (compare[0] == 0) { 30 if (!dentry->d_name.len) 31 return 0; 32 compare = "."; 33 } else if (compare[0] == 1) { 34 compare = ".."; 35 dlen = 2; 36 } 37 } 38 39 qstr.name = compare; 40 qstr.len = dlen; 41 return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr); 42 } 43 44 /* 45 * isofs_find_entry() 46 * 47 * finds an entry in the specified directory with the wanted name. It 48 * returns the inode number of the found entry, or 0 on error. 49 */ 50 static unsigned long 51 isofs_find_entry(struct inode *dir, struct dentry *dentry, 52 unsigned long *block_rv, unsigned long* offset_rv, 53 char * tmpname, struct iso_directory_record * tmpde) 54 { 55 unsigned long bufsize = ISOFS_BUFFER_SIZE(dir); 56 unsigned char bufbits = ISOFS_BUFFER_BITS(dir); 57 unsigned long block, f_pos, offset, block_saved, offset_saved; 58 struct buffer_head * bh = NULL; 59 struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb); 60 61 if (!ISOFS_I(dir)->i_first_extent) 62 return 0; 63 64 f_pos = 0; 65 offset = 0; 66 block = 0; 67 68 while (f_pos < dir->i_size) { 69 struct iso_directory_record * de; 70 int de_len, match, i, dlen; 71 char *dpnt; 72 73 if (!bh) { 74 bh = isofs_bread(dir, block); 75 if (!bh) 76 return 0; 77 } 78 79 de = (struct iso_directory_record *) (bh->b_data + offset); 80 81 de_len = *(unsigned char *) de; 82 if (!de_len) { 83 brelse(bh); 84 bh = NULL; 85 f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); 86 block = f_pos >> bufbits; 87 offset = 0; 88 continue; 89 } 90 91 block_saved = bh->b_blocknr; 92 offset_saved = offset; 93 offset += de_len; 94 f_pos += de_len; 95 96 /* Make sure we have a full directory entry */ 97 if (offset >= bufsize) { 98 int slop = bufsize - offset + de_len; 99 memcpy(tmpde, de, slop); 100 offset &= bufsize - 1; 101 block++; 102 brelse(bh); 103 bh = NULL; 104 if (offset) { 105 bh = isofs_bread(dir, block); 106 if (!bh) 107 return 0; 108 memcpy((void *) tmpde + slop, bh->b_data, offset); 109 } 110 de = tmpde; 111 } 112 113 dlen = de->name_len[0]; 114 dpnt = de->name; 115 116 if (sbi->s_rock && 117 ((i = get_rock_ridge_filename(de, tmpname, dir)))) { 118 dlen = i; /* possibly -1 */ 119 dpnt = tmpname; 120 #ifdef CONFIG_JOLIET 121 } else if (sbi->s_joliet_level) { 122 dlen = get_joliet_filename(de, tmpname, dir); 123 dpnt = tmpname; 124 #endif 125 } else if (sbi->s_mapping == 'a') { 126 dlen = get_acorn_filename(de, tmpname, dir); 127 dpnt = tmpname; 128 } else if (sbi->s_mapping == 'n') { 129 dlen = isofs_name_translate(de, tmpname, dir); 130 dpnt = tmpname; 131 } 132 133 /* 134 * Skip hidden or associated files unless hide or showassoc, 135 * respectively, is set 136 */ 137 match = 0; 138 if (dlen > 0 && 139 (sbi->s_hide =='n' || 140 (!(de->flags[-sbi->s_high_sierra] & 1))) && 141 (sbi->s_showassoc =='y' || 142 (!(de->flags[-sbi->s_high_sierra] & 4)))) { 143 match = (isofs_cmp(dentry, dpnt, dlen) == 0); 144 } 145 if (match) { 146 isofs_normalize_block_and_offset(de, 147 &block_saved, 148 &offset_saved); 149 *block_rv = block_saved; 150 *offset_rv = offset_saved; 151 brelse(bh); 152 return 1; 153 } 154 } 155 brelse(bh); 156 return 0; 157 } 158 159 struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 160 { 161 int found; 162 unsigned long block, offset; 163 struct inode *inode; 164 struct page *page; 165 166 dentry->d_op = dir->i_sb->s_root->d_op; 167 168 page = alloc_page(GFP_USER); 169 if (!page) 170 return ERR_PTR(-ENOMEM); 171 172 lock_kernel(); 173 found = isofs_find_entry(dir, dentry, 174 &block, &offset, 175 page_address(page), 176 1024 + page_address(page)); 177 __free_page(page); 178 179 inode = NULL; 180 if (found) { 181 inode = isofs_iget(dir->i_sb, block, offset); 182 if (!inode) { 183 unlock_kernel(); 184 return ERR_PTR(-EACCES); 185 } 186 } 187 unlock_kernel(); 188 return d_splice_alias(inode, dentry); 189 } 190