1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/isofs/dir.c 4 * 5 * (C) 1992, 1993, 1994 Eric Youngdale Modified for ISO 9660 filesystem. 6 * 7 * (C) 1991 Linus Torvalds - minix filesystem 8 * 9 * Steve Beynon : Missing last directory entries fixed 10 * (stephen@askone.demon.co.uk) : 21st June 1996 11 * 12 * isofs directory handling functions 13 */ 14 #include <linux/gfp.h> 15 #include "isofs.h" 16 17 int 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@infradead.org> 1998 */ 50 int 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 (de->length[0] - 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 */ 82 static int do_isofs_readdir(struct inode *inode, struct file *file, 83 struct dir_context *ctx, 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 = ctx->pos & (bufsize - 1); 99 block = ctx->pos >> bufbits; 100 101 while (ctx->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 ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); 124 block = ctx->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 brelse(bh); 156 return -EIO; 157 } 158 159 if (first_de) { 160 isofs_normalize_block_and_offset(de, 161 &block_saved, 162 &offset_saved); 163 inode_number = isofs_get_ino(block_saved, 164 offset_saved, bufbits); 165 } 166 167 if (de->flags[-sbi->s_high_sierra] & 0x80) { 168 first_de = 0; 169 ctx->pos += de_len; 170 continue; 171 } 172 first_de = 1; 173 174 /* Handle the case of the '.' directory */ 175 if (de->name_len[0] == 1 && de->name[0] == 0) { 176 if (!dir_emit_dot(file, ctx)) 177 break; 178 ctx->pos += de_len; 179 continue; 180 } 181 182 len = 0; 183 184 /* Handle the case of the '..' directory */ 185 if (de->name_len[0] == 1 && de->name[0] == 1) { 186 if (!dir_emit_dotdot(file, ctx)) 187 break; 188 ctx->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 ctx->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 (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN)) 235 break; 236 } 237 ctx->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 */ 251 static int isofs_readdir(struct file *file, struct dir_context *ctx) 252 { 253 int result; 254 char *tmpname; 255 struct iso_directory_record *tmpde; 256 struct inode *inode = file_inode(file); 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, file, ctx, 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 .iterate_shared = 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