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 <linux/slab.h> 17 #include "isofs.h" 18 #include <linux/fileattr.h> 19 20 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode) 21 { 22 char * old = de->name; 23 int len = de->name_len[0]; 24 int i; 25 26 for (i = 0; i < len; i++) { 27 unsigned char c = old[i]; 28 if (!c) 29 break; 30 31 if (c >= 'A' && c <= 'Z') 32 c |= 0x20; /* lower case */ 33 34 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */ 35 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1') 36 break; 37 38 /* Drop trailing ';1' */ 39 if (c == ';' && i == len - 2 && old[i + 1] == '1') 40 break; 41 42 /* Convert remaining ';' to '.' */ 43 /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */ 44 if (c == ';' || c == '/') 45 c = '.'; 46 47 new[i] = c; 48 } 49 return i; 50 } 51 52 /* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */ 53 int get_acorn_filename(struct iso_directory_record *de, 54 char *retname, struct inode *inode) 55 { 56 int std; 57 unsigned char *chr; 58 int retnamlen = isofs_name_translate(de, retname, inode); 59 60 if (retnamlen == 0) 61 return 0; 62 std = sizeof(struct iso_directory_record) + de->name_len[0]; 63 if (std & 1) 64 std++; 65 if (de->length[0] - std != 32) 66 return retnamlen; 67 chr = ((unsigned char *) de) + std; 68 if (strncmp(chr, "ARCHIMEDES", 10)) 69 return retnamlen; 70 if ((*retname == '_') && ((chr[19] & 1) == 1)) 71 *retname = '!'; 72 if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff) 73 && ((chr[12] & 0xf0) == 0xf0)) { 74 retname[retnamlen] = ','; 75 sprintf(retname+retnamlen+1, "%3.3x", 76 ((chr[12] & 0xf) << 8) | chr[11]); 77 retnamlen += 4; 78 } 79 return retnamlen; 80 } 81 82 /* 83 * This should _really_ be cleaned up some day.. 84 */ 85 static int do_isofs_readdir(struct inode *inode, struct file *file, 86 struct dir_context *ctx, 87 char *tmpname, struct iso_directory_record *tmpde) 88 { 89 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode); 90 unsigned char bufbits = ISOFS_BUFFER_BITS(inode); 91 unsigned long block, offset, block_saved, offset_saved; 92 unsigned long inode_number = 0; /* Quiet GCC */ 93 struct buffer_head *bh = NULL; 94 int len; 95 int map; 96 int first_de = 1; 97 char *p = NULL; /* Quiet GCC */ 98 struct iso_directory_record *de; 99 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb); 100 101 offset = ctx->pos & (bufsize - 1); 102 block = ctx->pos >> bufbits; 103 104 while (ctx->pos < inode->i_size) { 105 int de_len; 106 107 if (!bh) { 108 bh = isofs_bread(inode, block); 109 if (!bh) 110 return 0; 111 } 112 113 de = (struct iso_directory_record *) (bh->b_data + offset); 114 115 de_len = *(unsigned char *)de; 116 117 /* 118 * If the length byte is zero, we should move on to the next 119 * CDROM sector. If we are at the end of the directory, we 120 * kick out of the while loop. 121 */ 122 123 if (de_len == 0) { 124 brelse(bh); 125 bh = NULL; 126 ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); 127 block = ctx->pos >> bufbits; 128 offset = 0; 129 continue; 130 } 131 132 block_saved = block; 133 offset_saved = offset; 134 offset += de_len; 135 136 /* Make sure we have a full directory entry */ 137 if (offset >= bufsize) { 138 int slop = bufsize - offset + de_len; 139 memcpy(tmpde, de, slop); 140 offset &= bufsize - 1; 141 block++; 142 brelse(bh); 143 bh = NULL; 144 if (offset) { 145 bh = isofs_bread(inode, block); 146 if (!bh) 147 return 0; 148 memcpy((void *) tmpde + slop, bh->b_data, offset); 149 } 150 de = tmpde; 151 } 152 /* Basic sanity check, whether name doesn't exceed dir entry */ 153 if (de_len < sizeof(struct iso_directory_record) || 154 de_len < de->name_len[0] + 155 sizeof(struct iso_directory_record)) { 156 printk(KERN_NOTICE "iso9660: Corrupted directory entry" 157 " in block %lu of inode %llu\n", block, 158 inode->i_ino); 159 brelse(bh); 160 return -EIO; 161 } 162 163 if (first_de) { 164 isofs_normalize_block_and_offset(de, 165 &block_saved, 166 &offset_saved); 167 inode_number = isofs_get_ino(block_saved, 168 offset_saved, bufbits); 169 } 170 171 if (de->flags[-sbi->s_high_sierra] & 0x80) { 172 first_de = 0; 173 ctx->pos += de_len; 174 continue; 175 } 176 first_de = 1; 177 178 /* Handle the case of the '.' directory */ 179 if (de->name_len[0] == 1 && de->name[0] == 0) { 180 if (!dir_emit_dot(file, ctx)) 181 break; 182 ctx->pos += de_len; 183 continue; 184 } 185 186 len = 0; 187 188 /* Handle the case of the '..' directory */ 189 if (de->name_len[0] == 1 && de->name[0] == 1) { 190 if (!dir_emit_dotdot(file, ctx)) 191 break; 192 ctx->pos += de_len; 193 continue; 194 } 195 196 /* Handle everything else. Do name translation if there 197 is no Rock Ridge NM field. */ 198 199 /* 200 * Do not report hidden files if so instructed, or associated 201 * files unless instructed to do so 202 */ 203 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) || 204 (!sbi->s_showassoc && 205 (de->flags[-sbi->s_high_sierra] & 4))) { 206 ctx->pos += de_len; 207 continue; 208 } 209 210 map = 1; 211 if (sbi->s_rock) { 212 len = get_rock_ridge_filename(de, tmpname, inode); 213 if (len != 0) { /* may be -1 */ 214 p = tmpname; 215 map = 0; 216 } 217 } 218 if (map) { 219 #ifdef CONFIG_JOLIET 220 if (sbi->s_joliet_level) { 221 len = get_joliet_filename(de, tmpname, inode); 222 p = tmpname; 223 } else 224 #endif 225 if (sbi->s_mapping == 'a') { 226 len = get_acorn_filename(de, tmpname, inode); 227 p = tmpname; 228 } else 229 if (sbi->s_mapping == 'n') { 230 len = isofs_name_translate(de, tmpname, inode); 231 p = tmpname; 232 } else { 233 p = de->name; 234 len = de->name_len[0]; 235 } 236 } 237 if (len > 0) { 238 if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN)) 239 break; 240 } 241 ctx->pos += de_len; 242 } 243 if (bh) 244 brelse(bh); 245 return 0; 246 } 247 248 /* 249 * Handle allocation of temporary space for name translation and 250 * handling split directory entries.. The real work is done by 251 * "do_isofs_readdir()". 252 */ 253 static int isofs_readdir(struct file *file, struct dir_context *ctx) 254 { 255 int result; 256 char *tmpname; 257 struct iso_directory_record *tmpde; 258 struct inode *inode = file_inode(file); 259 260 tmpname = kmalloc(PAGE_SIZE, GFP_KERNEL); 261 if (tmpname == NULL) 262 return -ENOMEM; 263 264 tmpde = (struct iso_directory_record *) (tmpname+1024); 265 266 result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde); 267 268 kfree(tmpname); 269 return result; 270 } 271 272 int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa) 273 { 274 struct isofs_sb_info *sbi = ISOFS_SB(dentry->d_sb); 275 276 if (sbi->s_check == 'r') { 277 fa->fsx_xflags |= FS_XFLAG_CASEFOLD; 278 fa->flags |= FS_CASEFOLD_FL; 279 } 280 if (!sbi->s_joliet_level && !sbi->s_rock && 281 (sbi->s_mapping == 'n' || sbi->s_mapping == 'a')) 282 fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING; 283 return 0; 284 } 285 286 const struct file_operations isofs_dir_operations = 287 { 288 .llseek = generic_file_llseek, 289 .read = generic_read_dir, 290 .iterate_shared = isofs_readdir, 291 .setlease = generic_setlease, 292 }; 293 294 /* 295 * directories can handle most operations... 296 */ 297 const struct inode_operations isofs_dir_inode_operations = 298 { 299 .lookup = isofs_lookup, 300 .fileattr_get = isofs_fileattr_get, 301 }; 302 303 304