1 // SPDX-License-Identifier: MIT 2 /* 3 * VirtualBox Guest Shared Folders support: Directory inode and file operations 4 * 5 * Copyright (C) 2006-2018 Oracle Corporation 6 */ 7 8 #include <linux/namei.h> 9 #include <linux/vbox_utils.h> 10 #include "vfsmod.h" 11 12 static int vboxsf_dir_open(struct inode *inode, struct file *file) 13 { 14 struct vboxsf_sbi *sbi = VBOXSF_SBI(inode->i_sb); 15 struct shfl_createparms params = {}; 16 struct vboxsf_dir_info *sf_d; 17 int err; 18 19 sf_d = vboxsf_dir_info_alloc(); 20 if (!sf_d) 21 return -ENOMEM; 22 23 params.handle = SHFL_HANDLE_NIL; 24 params.create_flags = SHFL_CF_DIRECTORY | SHFL_CF_ACT_OPEN_IF_EXISTS | 25 SHFL_CF_ACT_FAIL_IF_NEW | SHFL_CF_ACCESS_READ; 26 27 err = vboxsf_create_at_dentry(file_dentry(file), ¶ms); 28 if (err) 29 goto err_free_dir_info; 30 31 if (params.result != SHFL_FILE_EXISTS) { 32 err = -ENOENT; 33 goto err_close; 34 } 35 36 err = vboxsf_dir_read_all(sbi, sf_d, params.handle); 37 if (err) 38 goto err_close; 39 40 vboxsf_close(sbi->root, params.handle); 41 file->private_data = sf_d; 42 return 0; 43 44 err_close: 45 vboxsf_close(sbi->root, params.handle); 46 err_free_dir_info: 47 vboxsf_dir_info_free(sf_d); 48 return err; 49 } 50 51 static int vboxsf_dir_release(struct inode *inode, struct file *file) 52 { 53 if (file->private_data) 54 vboxsf_dir_info_free(file->private_data); 55 56 return 0; 57 } 58 59 static unsigned int vboxsf_get_d_type(u32 mode) 60 { 61 unsigned int d_type; 62 63 switch (mode & SHFL_TYPE_MASK) { 64 case SHFL_TYPE_FIFO: 65 d_type = DT_FIFO; 66 break; 67 case SHFL_TYPE_DEV_CHAR: 68 d_type = DT_CHR; 69 break; 70 case SHFL_TYPE_DIRECTORY: 71 d_type = DT_DIR; 72 break; 73 case SHFL_TYPE_DEV_BLOCK: 74 d_type = DT_BLK; 75 break; 76 case SHFL_TYPE_FILE: 77 d_type = DT_REG; 78 break; 79 case SHFL_TYPE_SYMLINK: 80 d_type = DT_LNK; 81 break; 82 case SHFL_TYPE_SOCKET: 83 d_type = DT_SOCK; 84 break; 85 case SHFL_TYPE_WHITEOUT: 86 d_type = DT_WHT; 87 break; 88 default: 89 d_type = DT_UNKNOWN; 90 break; 91 } 92 return d_type; 93 } 94 95 static bool vboxsf_dir_emit(struct file *dir, struct dir_context *ctx) 96 { 97 struct vboxsf_sbi *sbi = VBOXSF_SBI(file_inode(dir)->i_sb); 98 struct vboxsf_dir_info *sf_d = dir->private_data; 99 struct shfl_dirinfo *info; 100 struct vboxsf_dir_buf *b; 101 unsigned int d_type; 102 loff_t i, cur = 0; 103 ino_t fake_ino; 104 void *end; 105 int err; 106 107 list_for_each_entry(b, &sf_d->info_list, head) { 108 try_next_entry: 109 if (ctx->pos >= cur + b->entries) { 110 cur += b->entries; 111 continue; 112 } 113 114 /* 115 * Note the vboxsf_dir_info objects we are iterating over here 116 * are variable sized, so the info pointer may end up being 117 * unaligned. This is how we get the data from the host. 118 * Since vboxsf is only supported on x86 machines this is not 119 * a problem. 120 */ 121 for (i = 0, info = b->buf; i < ctx->pos - cur; i++) { 122 end = &info->name.string.utf8[info->name.size]; 123 /* Only happens if the host gives us corrupt data */ 124 if (WARN_ON(end > (b->buf + b->used))) 125 return false; 126 info = end; 127 } 128 129 end = &info->name.string.utf8[info->name.size]; 130 if (WARN_ON(end > (b->buf + b->used))) 131 return false; 132 133 /* Info now points to the right entry, emit it. */ 134 d_type = vboxsf_get_d_type(info->info.attr.mode); 135 136 /* 137 * On 32-bit systems pos is 64-bit signed, while ino is 32-bit 138 * unsigned so fake_ino may overflow, check for this. 139 */ 140 if ((ino_t)(ctx->pos + 1) != (u64)(ctx->pos + 1)) { 141 vbg_err("vboxsf: fake ino overflow, truncating dir\n"); 142 return false; 143 } 144 fake_ino = ctx->pos + 1; 145 146 if (sbi->nls) { 147 char d_name[NAME_MAX]; 148 149 err = vboxsf_nlscpy(sbi, d_name, NAME_MAX, 150 info->name.string.utf8, 151 info->name.length); 152 if (err) { 153 /* skip erroneous entry and proceed */ 154 ctx->pos += 1; 155 goto try_next_entry; 156 } 157 158 return dir_emit(ctx, d_name, strlen(d_name), 159 fake_ino, d_type); 160 } 161 162 return dir_emit(ctx, info->name.string.utf8, info->name.length, 163 fake_ino, d_type); 164 } 165 166 return false; 167 } 168 169 static int vboxsf_dir_iterate(struct file *dir, struct dir_context *ctx) 170 { 171 bool emitted; 172 173 do { 174 emitted = vboxsf_dir_emit(dir, ctx); 175 if (emitted) 176 ctx->pos += 1; 177 } while (emitted); 178 179 return 0; 180 } 181 182 const struct file_operations vboxsf_dir_fops = { 183 .open = vboxsf_dir_open, 184 .iterate = vboxsf_dir_iterate, 185 .release = vboxsf_dir_release, 186 .read = generic_read_dir, 187 .llseek = generic_file_llseek, 188 }; 189 190 /* 191 * This is called during name resolution/lookup to check if the @dentry in 192 * the cache is still valid. the job is handled by vboxsf_inode_revalidate. 193 */ 194 static int vboxsf_dentry_revalidate(struct dentry *dentry, unsigned int flags) 195 { 196 if (flags & LOOKUP_RCU) 197 return -ECHILD; 198 199 if (d_really_is_positive(dentry)) 200 return vboxsf_inode_revalidate(dentry) == 0; 201 else 202 return vboxsf_stat_dentry(dentry, NULL) == -ENOENT; 203 } 204 205 const struct dentry_operations vboxsf_dentry_ops = { 206 .d_revalidate = vboxsf_dentry_revalidate 207 }; 208 209 /* iops */ 210 211 static struct dentry *vboxsf_dir_lookup(struct inode *parent, 212 struct dentry *dentry, 213 unsigned int flags) 214 { 215 struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb); 216 struct shfl_fsobjinfo fsinfo; 217 struct inode *inode; 218 int err; 219 220 dentry->d_time = jiffies; 221 222 err = vboxsf_stat_dentry(dentry, &fsinfo); 223 if (err) { 224 inode = (err == -ENOENT) ? NULL : ERR_PTR(err); 225 } else { 226 inode = vboxsf_new_inode(parent->i_sb); 227 if (!IS_ERR(inode)) 228 vboxsf_init_inode(sbi, inode, &fsinfo); 229 } 230 231 return d_splice_alias(inode, dentry); 232 } 233 234 static int vboxsf_dir_instantiate(struct inode *parent, struct dentry *dentry, 235 struct shfl_fsobjinfo *info) 236 { 237 struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb); 238 struct vboxsf_inode *sf_i; 239 struct inode *inode; 240 241 inode = vboxsf_new_inode(parent->i_sb); 242 if (IS_ERR(inode)) 243 return PTR_ERR(inode); 244 245 sf_i = VBOXSF_I(inode); 246 /* The host may have given us different attr then requested */ 247 sf_i->force_restat = 1; 248 vboxsf_init_inode(sbi, inode, info); 249 250 d_instantiate(dentry, inode); 251 252 return 0; 253 } 254 255 static int vboxsf_dir_create(struct inode *parent, struct dentry *dentry, 256 umode_t mode, int is_dir) 257 { 258 struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent); 259 struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb); 260 struct shfl_createparms params = {}; 261 int err; 262 263 params.handle = SHFL_HANDLE_NIL; 264 params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW | 265 SHFL_CF_ACT_FAIL_IF_EXISTS | 266 SHFL_CF_ACCESS_READWRITE | 267 (is_dir ? SHFL_CF_DIRECTORY : 0); 268 params.info.attr.mode = (mode & 0777) | 269 (is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE); 270 params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING; 271 272 err = vboxsf_create_at_dentry(dentry, ¶ms); 273 if (err) 274 return err; 275 276 if (params.result != SHFL_FILE_CREATED) 277 return -EPERM; 278 279 vboxsf_close(sbi->root, params.handle); 280 281 err = vboxsf_dir_instantiate(parent, dentry, ¶ms.info); 282 if (err) 283 return err; 284 285 /* parent directory access/change time changed */ 286 sf_parent_i->force_restat = 1; 287 288 return 0; 289 } 290 291 static int vboxsf_dir_mkfile(struct inode *parent, struct dentry *dentry, 292 umode_t mode, bool excl) 293 { 294 return vboxsf_dir_create(parent, dentry, mode, 0); 295 } 296 297 static int vboxsf_dir_mkdir(struct inode *parent, struct dentry *dentry, 298 umode_t mode) 299 { 300 return vboxsf_dir_create(parent, dentry, mode, 1); 301 } 302 303 static int vboxsf_dir_unlink(struct inode *parent, struct dentry *dentry) 304 { 305 struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb); 306 struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent); 307 struct inode *inode = d_inode(dentry); 308 struct shfl_string *path; 309 u32 flags; 310 int err; 311 312 if (S_ISDIR(inode->i_mode)) 313 flags = SHFL_REMOVE_DIR; 314 else 315 flags = SHFL_REMOVE_FILE; 316 317 if (S_ISLNK(inode->i_mode)) 318 flags |= SHFL_REMOVE_SYMLINK; 319 320 path = vboxsf_path_from_dentry(sbi, dentry); 321 if (IS_ERR(path)) 322 return PTR_ERR(path); 323 324 err = vboxsf_remove(sbi->root, path, flags); 325 __putname(path); 326 if (err) 327 return err; 328 329 /* parent directory access/change time changed */ 330 sf_parent_i->force_restat = 1; 331 332 return 0; 333 } 334 335 static int vboxsf_dir_rename(struct inode *old_parent, 336 struct dentry *old_dentry, 337 struct inode *new_parent, 338 struct dentry *new_dentry, 339 unsigned int flags) 340 { 341 struct vboxsf_sbi *sbi = VBOXSF_SBI(old_parent->i_sb); 342 struct vboxsf_inode *sf_old_parent_i = VBOXSF_I(old_parent); 343 struct vboxsf_inode *sf_new_parent_i = VBOXSF_I(new_parent); 344 u32 shfl_flags = SHFL_RENAME_FILE | SHFL_RENAME_REPLACE_IF_EXISTS; 345 struct shfl_string *old_path, *new_path; 346 int err; 347 348 if (flags) 349 return -EINVAL; 350 351 old_path = vboxsf_path_from_dentry(sbi, old_dentry); 352 if (IS_ERR(old_path)) 353 return PTR_ERR(old_path); 354 355 new_path = vboxsf_path_from_dentry(sbi, new_dentry); 356 if (IS_ERR(new_path)) { 357 err = PTR_ERR(new_path); 358 goto err_put_old_path; 359 } 360 361 if (d_inode(old_dentry)->i_mode & S_IFDIR) 362 shfl_flags = 0; 363 364 err = vboxsf_rename(sbi->root, old_path, new_path, shfl_flags); 365 if (err == 0) { 366 /* parent directories access/change time changed */ 367 sf_new_parent_i->force_restat = 1; 368 sf_old_parent_i->force_restat = 1; 369 } 370 371 __putname(new_path); 372 err_put_old_path: 373 __putname(old_path); 374 return err; 375 } 376 377 static int vboxsf_dir_symlink(struct inode *parent, struct dentry *dentry, 378 const char *symname) 379 { 380 struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent); 381 struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb); 382 int symname_size = strlen(symname) + 1; 383 struct shfl_string *path, *ssymname; 384 struct shfl_fsobjinfo info; 385 int err; 386 387 path = vboxsf_path_from_dentry(sbi, dentry); 388 if (IS_ERR(path)) 389 return PTR_ERR(path); 390 391 ssymname = kmalloc(SHFLSTRING_HEADER_SIZE + symname_size, GFP_KERNEL); 392 if (!ssymname) { 393 __putname(path); 394 return -ENOMEM; 395 } 396 ssymname->length = symname_size - 1; 397 ssymname->size = symname_size; 398 memcpy(ssymname->string.utf8, symname, symname_size); 399 400 err = vboxsf_symlink(sbi->root, path, ssymname, &info); 401 kfree(ssymname); 402 __putname(path); 403 if (err) { 404 /* -EROFS means symlinks are note support -> -EPERM */ 405 return (err == -EROFS) ? -EPERM : err; 406 } 407 408 err = vboxsf_dir_instantiate(parent, dentry, &info); 409 if (err) 410 return err; 411 412 /* parent directory access/change time changed */ 413 sf_parent_i->force_restat = 1; 414 return 0; 415 } 416 417 const struct inode_operations vboxsf_dir_iops = { 418 .lookup = vboxsf_dir_lookup, 419 .create = vboxsf_dir_mkfile, 420 .mkdir = vboxsf_dir_mkdir, 421 .rmdir = vboxsf_dir_unlink, 422 .unlink = vboxsf_dir_unlink, 423 .rename = vboxsf_dir_rename, 424 .symlink = vboxsf_dir_symlink, 425 .getattr = vboxsf_getattr, 426 .setattr = vboxsf_setattr, 427 }; 428