1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * QNX6 file system, Linux implementation. 4 * 5 * Version : 1.0.0 6 * 7 * History : 8 * 9 * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release. 10 * 16-02-2012 pagemap extension by Al Viro 11 * 12 */ 13 14 #include "qnx6.h" 15 16 static unsigned qnx6_lfile_checksum(char *name, unsigned size) 17 { 18 unsigned crc = 0; 19 char *end = name + size; 20 while (name < end) { 21 crc = ((crc >> 1) + *(name++)) ^ 22 ((crc & 0x00000001) ? 0x80000000 : 0); 23 } 24 return crc; 25 } 26 27 static void *qnx6_get_folio(struct inode *dir, unsigned long n, 28 struct folio **foliop) 29 { 30 struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL); 31 32 if (IS_ERR(folio)) 33 return folio; 34 *foliop = folio; 35 return kmap_local_folio(folio, 0); 36 } 37 38 static unsigned last_entry(struct inode *inode, unsigned long page_nr) 39 { 40 unsigned long last_byte = inode->i_size; 41 last_byte -= page_nr << PAGE_SHIFT; 42 if (last_byte > PAGE_SIZE) 43 last_byte = PAGE_SIZE; 44 return last_byte / QNX6_DIR_ENTRY_SIZE; 45 } 46 47 static struct qnx6_long_filename *qnx6_longname(struct super_block *sb, 48 struct qnx6_long_dir_entry *de, 49 struct folio **foliop) 50 { 51 struct qnx6_sb_info *sbi = QNX6_SB(sb); 52 u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */ 53 u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */ 54 u32 offs; 55 struct address_space *mapping = sbi->longfile->i_mapping; 56 struct folio *folio = read_mapping_folio(mapping, n, NULL); 57 58 if (IS_ERR(folio)) 59 return ERR_CAST(folio); 60 offs = offset_in_folio(folio, s << sb->s_blocksize_bits); 61 *foliop = folio; 62 return kmap_local_folio(folio, offs); 63 } 64 65 static int qnx6_dir_longfilename(struct inode *inode, 66 struct qnx6_long_dir_entry *de, 67 struct dir_context *ctx, 68 unsigned de_inode) 69 { 70 struct qnx6_long_filename *lf; 71 struct super_block *s = inode->i_sb; 72 struct qnx6_sb_info *sbi = QNX6_SB(s); 73 struct folio *folio; 74 int lf_size; 75 76 if (de->de_size != 0xff) { 77 /* error - long filename entries always have size 0xff 78 in direntry */ 79 pr_err("invalid direntry size (%i).\n", de->de_size); 80 return 0; 81 } 82 lf = qnx6_longname(s, de, &folio); 83 if (IS_ERR(lf)) { 84 pr_err("Error reading longname\n"); 85 return 0; 86 } 87 88 lf_size = fs16_to_cpu(sbi, lf->lf_size); 89 90 if (lf_size > QNX6_LONG_NAME_MAX) { 91 pr_debug("file %s\n", lf->lf_fname); 92 pr_err("Filename too long (%i)\n", lf_size); 93 folio_release_kmap(folio, lf); 94 return 0; 95 } 96 97 /* calc & validate longfilename checksum 98 mmi 3g filesystem does not have that checksum */ 99 if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) != 100 qnx6_lfile_checksum(lf->lf_fname, lf_size)) 101 pr_info("long filename checksum error.\n"); 102 103 pr_debug("qnx6_readdir:%.*s inode:%u\n", 104 lf_size, lf->lf_fname, de_inode); 105 if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) { 106 folio_release_kmap(folio, lf); 107 return 0; 108 } 109 110 folio_release_kmap(folio, lf); 111 /* success */ 112 return 1; 113 } 114 115 static int qnx6_readdir(struct file *file, struct dir_context *ctx) 116 { 117 struct inode *inode = file_inode(file); 118 struct super_block *s = inode->i_sb; 119 struct qnx6_sb_info *sbi = QNX6_SB(s); 120 loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1); 121 unsigned long npages = dir_pages(inode); 122 unsigned long n = pos >> PAGE_SHIFT; 123 unsigned offset = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE; 124 bool done = false; 125 126 ctx->pos = pos; 127 if (ctx->pos >= inode->i_size) 128 return 0; 129 130 for ( ; !done && n < npages; n++, offset = 0) { 131 struct qnx6_dir_entry *de; 132 struct folio *folio; 133 char *kaddr = qnx6_get_folio(inode, n, &folio); 134 char *limit; 135 136 if (IS_ERR(kaddr)) { 137 pr_err("%s(): read failed\n", __func__); 138 ctx->pos = (n + 1) << PAGE_SHIFT; 139 return PTR_ERR(kaddr); 140 } 141 de = (struct qnx6_dir_entry *)(kaddr + offset); 142 limit = kaddr + last_entry(inode, n); 143 for (; (char *)de < limit; de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) { 144 int size = de->de_size; 145 u32 no_inode = fs32_to_cpu(sbi, de->de_inode); 146 147 if (!no_inode || !size) 148 continue; 149 150 if (size > QNX6_SHORT_NAME_MAX) { 151 /* long filename detected 152 get the filename from long filename 153 structure / block */ 154 if (!qnx6_dir_longfilename(inode, 155 (struct qnx6_long_dir_entry *)de, 156 ctx, no_inode)) { 157 done = true; 158 break; 159 } 160 } else { 161 pr_debug("%s():%.*s inode:%u\n", 162 __func__, size, de->de_fname, 163 no_inode); 164 if (!dir_emit(ctx, de->de_fname, size, 165 no_inode, DT_UNKNOWN)) { 166 done = true; 167 break; 168 } 169 } 170 } 171 folio_release_kmap(folio, kaddr); 172 } 173 return 0; 174 } 175 176 /* 177 * check if the long filename is correct. 178 */ 179 static unsigned qnx6_long_match(int len, const char *name, 180 struct qnx6_long_dir_entry *de, struct inode *dir) 181 { 182 struct super_block *s = dir->i_sb; 183 struct qnx6_sb_info *sbi = QNX6_SB(s); 184 struct folio *folio; 185 int thislen; 186 struct qnx6_long_filename *lf = qnx6_longname(s, de, &folio); 187 188 if (IS_ERR(lf)) 189 return 0; 190 191 thislen = fs16_to_cpu(sbi, lf->lf_size); 192 if (len != thislen) { 193 folio_release_kmap(folio, lf); 194 return 0; 195 } 196 if (memcmp(name, lf->lf_fname, len) == 0) { 197 folio_release_kmap(folio, lf); 198 return fs32_to_cpu(sbi, de->de_inode); 199 } 200 folio_release_kmap(folio, lf); 201 return 0; 202 } 203 204 /* 205 * check if the filename is correct. 206 */ 207 static unsigned qnx6_match(struct super_block *s, int len, const char *name, 208 struct qnx6_dir_entry *de) 209 { 210 struct qnx6_sb_info *sbi = QNX6_SB(s); 211 if (memcmp(name, de->de_fname, len) == 0) 212 return fs32_to_cpu(sbi, de->de_inode); 213 return 0; 214 } 215 216 217 unsigned qnx6_find_ino(int len, struct inode *dir, const char *name) 218 { 219 struct super_block *s = dir->i_sb; 220 struct qnx6_inode_info *ei = QNX6_I(dir); 221 struct folio *folio; 222 unsigned long start, n; 223 unsigned long npages = dir_pages(dir); 224 unsigned ino; 225 struct qnx6_dir_entry *de; 226 struct qnx6_long_dir_entry *lde; 227 228 if (npages == 0) 229 return 0; 230 start = ei->i_dir_start_lookup; 231 if (start >= npages) 232 start = 0; 233 n = start; 234 235 do { 236 de = qnx6_get_folio(dir, n, &folio); 237 if (!IS_ERR(de)) { 238 int limit = last_entry(dir, n); 239 int i; 240 241 for (i = 0; i < limit; i++, de++) { 242 if (len <= QNX6_SHORT_NAME_MAX) { 243 /* short filename */ 244 if (len != de->de_size) 245 continue; 246 ino = qnx6_match(s, len, name, de); 247 if (ino) 248 goto found; 249 } else if (de->de_size == 0xff) { 250 /* deal with long filename */ 251 lde = (struct qnx6_long_dir_entry *)de; 252 ino = qnx6_long_match(len, 253 name, lde, dir); 254 if (ino) 255 goto found; 256 } else 257 pr_err("undefined filename size in inode.\n"); 258 } 259 folio_release_kmap(folio, de - i); 260 } 261 262 if (++n >= npages) 263 n = 0; 264 } while (n != start); 265 return 0; 266 267 found: 268 ei->i_dir_start_lookup = n; 269 folio_release_kmap(folio, de); 270 return ino; 271 } 272 273 const struct file_operations qnx6_dir_operations = { 274 .llseek = generic_file_llseek, 275 .read = generic_read_dir, 276 .iterate_shared = qnx6_readdir, 277 .fsync = generic_file_fsync, 278 }; 279 280 const struct inode_operations qnx6_dir_inode_operations = { 281 .lookup = qnx6_lookup, 282 }; 283