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) 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 if (!isofs_dir_record_valid(de, offset_saved, bufsize)) { 137 printk(KERN_NOTICE "iso9660: Corrupted directory entry" 138 " in block %lu of inode %llu\n", block, 139 inode->i_ino); 140 brelse(bh); 141 return -EIO; 142 } 143 144 if (first_de) { 145 isofs_normalize_block_and_offset(de, 146 &block_saved, 147 &offset_saved); 148 inode_number = isofs_get_ino(block_saved, 149 offset_saved, bufbits); 150 } 151 152 if (de->flags[-sbi->s_high_sierra] & 0x80) { 153 first_de = 0; 154 ctx->pos += de_len; 155 continue; 156 } 157 first_de = 1; 158 159 /* Handle the case of the '.' directory */ 160 if (de->name_len[0] == 1 && de->name[0] == 0) { 161 if (!dir_emit_dot(file, ctx)) 162 break; 163 ctx->pos += de_len; 164 continue; 165 } 166 167 len = 0; 168 169 /* Handle the case of the '..' directory */ 170 if (de->name_len[0] == 1 && de->name[0] == 1) { 171 if (!dir_emit_dotdot(file, ctx)) 172 break; 173 ctx->pos += de_len; 174 continue; 175 } 176 177 /* Handle everything else. Do name translation if there 178 is no Rock Ridge NM field. */ 179 180 /* 181 * Do not report hidden files if so instructed, or associated 182 * files unless instructed to do so 183 */ 184 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) || 185 (!sbi->s_showassoc && 186 (de->flags[-sbi->s_high_sierra] & 4))) { 187 ctx->pos += de_len; 188 continue; 189 } 190 191 map = 1; 192 if (sbi->s_rock) { 193 len = get_rock_ridge_filename(de, tmpname, inode); 194 if (len != 0) { /* may be -1 */ 195 p = tmpname; 196 map = 0; 197 } 198 } 199 if (map) { 200 #ifdef CONFIG_JOLIET 201 if (sbi->s_joliet_level) { 202 len = get_joliet_filename(de, tmpname, inode); 203 p = tmpname; 204 } else 205 #endif 206 if (sbi->s_mapping == 'a') { 207 len = get_acorn_filename(de, tmpname, inode); 208 p = tmpname; 209 } else 210 if (sbi->s_mapping == 'n') { 211 len = isofs_name_translate(de, tmpname, inode); 212 p = tmpname; 213 } else { 214 p = de->name; 215 len = de->name_len[0]; 216 } 217 } 218 if (len > 0) { 219 if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN)) 220 break; 221 } 222 ctx->pos += de_len; 223 } 224 if (bh) 225 brelse(bh); 226 return 0; 227 } 228 229 /* 230 * Handle allocation of temporary space for name translation and 231 * handling split directory entries.. The real work is done by 232 * "do_isofs_readdir()". 233 */ 234 static int isofs_readdir(struct file *file, struct dir_context *ctx) 235 { 236 int result; 237 char *tmpname; 238 struct inode *inode = file_inode(file); 239 240 tmpname = kmalloc(1024, GFP_KERNEL); 241 if (tmpname == NULL) 242 return -ENOMEM; 243 244 result = do_isofs_readdir(inode, file, ctx, tmpname); 245 246 kfree(tmpname); 247 return result; 248 } 249 250 int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa) 251 { 252 struct isofs_sb_info *sbi = ISOFS_SB(dentry->d_sb); 253 254 if (sbi->s_check == 'r') { 255 fa->fsx_xflags |= FS_XFLAG_CASEFOLD; 256 fa->flags |= FS_CASEFOLD_FL; 257 } 258 if (!sbi->s_joliet_level && !sbi->s_rock && 259 (sbi->s_mapping == 'n' || sbi->s_mapping == 'a')) 260 fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING; 261 return 0; 262 } 263 264 const struct file_operations isofs_dir_operations = 265 { 266 .llseek = generic_file_llseek, 267 .read = generic_read_dir, 268 .iterate_shared = isofs_readdir, 269 .setlease = generic_setlease, 270 }; 271 272 /* 273 * directories can handle most operations... 274 */ 275 const struct inode_operations isofs_dir_inode_operations = 276 { 277 .lookup = isofs_lookup, 278 .fileattr_get = isofs_fileattr_get, 279 }; 280 281