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 <linux/filelock.h> 16 #include "isofs.h" 17 18 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode) 19 { 20 char * old = de->name; 21 int len = de->name_len[0]; 22 int i; 23 24 for (i = 0; i < len; i++) { 25 unsigned char c = old[i]; 26 if (!c) 27 break; 28 29 if (c >= 'A' && c <= 'Z') 30 c |= 0x20; /* lower case */ 31 32 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */ 33 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1') 34 break; 35 36 /* Drop trailing ';1' */ 37 if (c == ';' && i == len - 2 && old[i + 1] == '1') 38 break; 39 40 /* Convert remaining ';' to '.' */ 41 /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */ 42 if (c == ';' || c == '/') 43 c = '.'; 44 45 new[i] = c; 46 } 47 return i; 48 } 49 50 /* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */ 51 int get_acorn_filename(struct iso_directory_record *de, 52 char *retname, struct inode *inode) 53 { 54 int std; 55 unsigned char *chr; 56 int retnamlen = isofs_name_translate(de, retname, inode); 57 58 if (retnamlen == 0) 59 return 0; 60 std = sizeof(struct iso_directory_record) + de->name_len[0]; 61 if (std & 1) 62 std++; 63 if (de->length[0] - std != 32) 64 return retnamlen; 65 chr = ((unsigned char *) de) + std; 66 if (strncmp(chr, "ARCHIMEDES", 10)) 67 return retnamlen; 68 if ((*retname == '_') && ((chr[19] & 1) == 1)) 69 *retname = '!'; 70 if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff) 71 && ((chr[12] & 0xf0) == 0xf0)) { 72 retname[retnamlen] = ','; 73 sprintf(retname+retnamlen+1, "%3.3x", 74 ((chr[12] & 0xf) << 8) | chr[11]); 75 retnamlen += 4; 76 } 77 return retnamlen; 78 } 79 80 /* 81 * This should _really_ be cleaned up some day.. 82 */ 83 static int do_isofs_readdir(struct inode *inode, struct file *file, 84 struct dir_context *ctx, 85 char *tmpname, struct iso_directory_record *tmpde) 86 { 87 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode); 88 unsigned char bufbits = ISOFS_BUFFER_BITS(inode); 89 unsigned long block, offset, block_saved, offset_saved; 90 unsigned long inode_number = 0; /* Quiet GCC */ 91 struct buffer_head *bh = NULL; 92 int len; 93 int map; 94 int first_de = 1; 95 char *p = NULL; /* Quiet GCC */ 96 struct iso_directory_record *de; 97 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb); 98 99 offset = ctx->pos & (bufsize - 1); 100 block = ctx->pos >> bufbits; 101 102 while (ctx->pos < inode->i_size) { 103 int de_len; 104 105 if (!bh) { 106 bh = isofs_bread(inode, block); 107 if (!bh) 108 return 0; 109 } 110 111 de = (struct iso_directory_record *) (bh->b_data + offset); 112 113 de_len = *(unsigned char *)de; 114 115 /* 116 * If the length byte is zero, we should move on to the next 117 * CDROM sector. If we are at the end of the directory, we 118 * kick out of the while loop. 119 */ 120 121 if (de_len == 0) { 122 brelse(bh); 123 bh = NULL; 124 ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); 125 block = ctx->pos >> bufbits; 126 offset = 0; 127 continue; 128 } 129 130 block_saved = block; 131 offset_saved = offset; 132 offset += de_len; 133 134 /* Make sure we have a full directory entry */ 135 if (offset >= bufsize) { 136 int slop = bufsize - offset + de_len; 137 memcpy(tmpde, de, slop); 138 offset &= bufsize - 1; 139 block++; 140 brelse(bh); 141 bh = NULL; 142 if (offset) { 143 bh = isofs_bread(inode, block); 144 if (!bh) 145 return 0; 146 memcpy((void *) tmpde + slop, bh->b_data, offset); 147 } 148 de = tmpde; 149 } 150 /* Basic sanity check, whether name doesn't exceed dir entry */ 151 if (de_len < sizeof(struct iso_directory_record) || 152 de_len < de->name_len[0] + 153 sizeof(struct iso_directory_record)) { 154 printk(KERN_NOTICE "iso9660: Corrupted directory entry" 155 " in block %lu of inode %lu\n", block, 156 inode->i_ino); 157 brelse(bh); 158 return -EIO; 159 } 160 161 if (first_de) { 162 isofs_normalize_block_and_offset(de, 163 &block_saved, 164 &offset_saved); 165 inode_number = isofs_get_ino(block_saved, 166 offset_saved, bufbits); 167 } 168 169 if (de->flags[-sbi->s_high_sierra] & 0x80) { 170 first_de = 0; 171 ctx->pos += de_len; 172 continue; 173 } 174 first_de = 1; 175 176 /* Handle the case of the '.' directory */ 177 if (de->name_len[0] == 1 && de->name[0] == 0) { 178 if (!dir_emit_dot(file, ctx)) 179 break; 180 ctx->pos += de_len; 181 continue; 182 } 183 184 len = 0; 185 186 /* Handle the case of the '..' directory */ 187 if (de->name_len[0] == 1 && de->name[0] == 1) { 188 if (!dir_emit_dotdot(file, ctx)) 189 break; 190 ctx->pos += de_len; 191 continue; 192 } 193 194 /* Handle everything else. Do name translation if there 195 is no Rock Ridge NM field. */ 196 197 /* 198 * Do not report hidden files if so instructed, or associated 199 * files unless instructed to do so 200 */ 201 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) || 202 (!sbi->s_showassoc && 203 (de->flags[-sbi->s_high_sierra] & 4))) { 204 ctx->pos += de_len; 205 continue; 206 } 207 208 map = 1; 209 if (sbi->s_rock) { 210 len = get_rock_ridge_filename(de, tmpname, inode); 211 if (len != 0) { /* may be -1 */ 212 p = tmpname; 213 map = 0; 214 } 215 } 216 if (map) { 217 #ifdef CONFIG_JOLIET 218 if (sbi->s_joliet_level) { 219 len = get_joliet_filename(de, tmpname, inode); 220 p = tmpname; 221 } else 222 #endif 223 if (sbi->s_mapping == 'a') { 224 len = get_acorn_filename(de, tmpname, inode); 225 p = tmpname; 226 } else 227 if (sbi->s_mapping == 'n') { 228 len = isofs_name_translate(de, tmpname, inode); 229 p = tmpname; 230 } else { 231 p = de->name; 232 len = de->name_len[0]; 233 } 234 } 235 if (len > 0) { 236 if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN)) 237 break; 238 } 239 ctx->pos += de_len; 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 .setlease = generic_setlease, 276 }; 277 278 /* 279 * directories can handle most operations... 280 */ 281 const struct inode_operations isofs_dir_inode_operations = 282 { 283 .lookup = isofs_lookup, 284 }; 285 286 287