fs/vboxsf/dir.c

   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), &params);
  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 WRAP_DIR_ITER(vboxsf_dir_iterate) // FIXME!
 183 const struct file_operations vboxsf_dir_fops = {
 184         .open = vboxsf_dir_open,
 185         .iterate_shared = shared_vboxsf_dir_iterate,
 186         .release = vboxsf_dir_release,
 187         .read = generic_read_dir,
 188         .llseek = generic_file_llseek,
 189 };
 190
 191 /*
 192  * This is called during name resolution/lookup to check if the @dentry in
 193  * the cache is still valid. the job is handled by vboxsf_inode_revalidate.
 194  */
 195 static int vboxsf_dentry_revalidate(struct dentry *dentry, unsigned int flags)
 196 {
 197         if (flags & LOOKUP_RCU)
 198                 return -ECHILD;
 199
 200         if (d_really_is_positive(dentry))
 201                 return vboxsf_inode_revalidate(dentry) == 0;
 202         else
 203                 return vboxsf_stat_dentry(dentry, NULL) == -ENOENT;
 204 }
 205
 206 const struct dentry_operations vboxsf_dentry_ops = {
 207         .d_revalidate = vboxsf_dentry_revalidate
 208 };
 209
 210 /* iops */
 211
 212 static struct dentry *vboxsf_dir_lookup(struct inode *parent,
 213                                         struct dentry *dentry,
 214                                         unsigned int flags)
 215 {
 216         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 217         struct shfl_fsobjinfo fsinfo;
 218         struct inode *inode;
 219         int err;
 220
 221         dentry->d_time = jiffies;
 222
 223         err = vboxsf_stat_dentry(dentry, &fsinfo);
 224         if (err) {
 225                 inode = (err == -ENOENT) ? NULL : ERR_PTR(err);
 226         } else {
 227                 inode = vboxsf_new_inode(parent->i_sb);
 228                 if (!IS_ERR(inode))
 229                         vboxsf_init_inode(sbi, inode, &fsinfo, false);
 230         }
 231
 232         return d_splice_alias(inode, dentry);
 233 }
 234
 235 static int vboxsf_dir_instantiate(struct inode *parent, struct dentry *dentry,
 236                                   struct shfl_fsobjinfo *info)
 237 {
 238         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 239         struct vboxsf_inode *sf_i;
 240         struct inode *inode;
 241
 242         inode = vboxsf_new_inode(parent->i_sb);
 243         if (IS_ERR(inode))
 244                 return PTR_ERR(inode);
 245
 246         sf_i = VBOXSF_I(inode);
 247         /* The host may have given us different attr then requested */
 248         sf_i->force_restat = 1;
 249         vboxsf_init_inode(sbi, inode, info, false);
 250
 251         d_instantiate(dentry, inode);
 252
 253         return 0;
 254 }
 255
 256 static int vboxsf_dir_create(struct inode *parent, struct dentry *dentry,
 257                              umode_t mode, bool is_dir, bool excl, u64 *handle_ret)
 258 {
 259         struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 260         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 261         struct shfl_createparms params = {};
 262         int err;
 263
 264         params.handle = SHFL_HANDLE_NIL;
 265         params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW | SHFL_CF_ACCESS_READWRITE;
 266         if (is_dir)
 267                 params.create_flags |= SHFL_CF_DIRECTORY;
 268         if (excl)
 269                 params.create_flags |= SHFL_CF_ACT_FAIL_IF_EXISTS;
 270
 271         params.info.attr.mode = (mode & 0777) |
 272                                 (is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE);
 273         params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING;
 274
 275         err = vboxsf_create_at_dentry(dentry, &params);
 276         if (err)
 277                 return err;
 278
 279         if (params.result != SHFL_FILE_CREATED)
 280                 return -EPERM;
 281
 282         err = vboxsf_dir_instantiate(parent, dentry, &params.info);
 283         if (err)
 284                 goto out;
 285
 286         /* parent directory access/change time changed */
 287         sf_parent_i->force_restat = 1;
 288
 289 out:
 290         if (err == 0 && handle_ret)
 291                 *handle_ret = params.handle;
 292         else
 293                 vboxsf_close(sbi->root, params.handle);
 294
 295         return err;
 296 }
 297
 298 static int vboxsf_dir_mkfile(struct mnt_idmap *idmap,
 299                              struct inode *parent, struct dentry *dentry,
 300                              umode_t mode, bool excl)
 301 {
 302         return vboxsf_dir_create(parent, dentry, mode, false, excl, NULL);
 303 }
 304
 305 static int vboxsf_dir_mkdir(struct mnt_idmap *idmap,
 306                             struct inode *parent, struct dentry *dentry,
 307                             umode_t mode)
 308 {
 309         return vboxsf_dir_create(parent, dentry, mode, true, true, NULL);
 310 }
 311
 312 static int vboxsf_dir_atomic_open(struct inode *parent, struct dentry *dentry,
 313                                   struct file *file, unsigned int flags, umode_t mode)
 314 {
 315         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 316         struct vboxsf_handle *sf_handle;
 317         struct dentry *res = NULL;
 318         u64 handle;
 319         int err;
 320
 321         if (d_in_lookup(dentry)) {
 322                 res = vboxsf_dir_lookup(parent, dentry, 0);
 323                 if (IS_ERR(res))
 324                         return PTR_ERR(res);
 325
 326                 if (res)
 327                         dentry = res;
 328         }
 329
 330         /* Only creates */
 331         if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 332                 return finish_no_open(file, res);
 333
 334         err = vboxsf_dir_create(parent, dentry, mode, false, flags & O_EXCL, &handle);
 335         if (err)
 336                 goto out;
 337
 338         sf_handle = vboxsf_create_sf_handle(d_inode(dentry), handle, SHFL_CF_ACCESS_READWRITE);
 339         if (IS_ERR(sf_handle)) {
 340                 vboxsf_close(sbi->root, handle);
 341                 err = PTR_ERR(sf_handle);
 342                 goto out;
 343         }
 344
 345         err = finish_open(file, dentry, generic_file_open);
 346         if (err) {
 347                 /* This also closes the handle passed to vboxsf_create_sf_handle() */
 348                 vboxsf_release_sf_handle(d_inode(dentry), sf_handle);
 349                 goto out;
 350         }
 351
 352         file->private_data = sf_handle;
 353         file->f_mode |= FMODE_CREATED;
 354 out:
 355         dput(res);
 356         return err;
 357 }
 358
 359 static int vboxsf_dir_unlink(struct inode *parent, struct dentry *dentry)
 360 {
 361         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 362         struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 363         struct inode *inode = d_inode(dentry);
 364         struct shfl_string *path;
 365         u32 flags;
 366         int err;
 367
 368         if (S_ISDIR(inode->i_mode))
 369                 flags = SHFL_REMOVE_DIR;
 370         else
 371                 flags = SHFL_REMOVE_FILE;
 372
 373         if (S_ISLNK(inode->i_mode))
 374                 flags |= SHFL_REMOVE_SYMLINK;
 375
 376         path = vboxsf_path_from_dentry(sbi, dentry);
 377         if (IS_ERR(path))
 378                 return PTR_ERR(path);
 379
 380         err = vboxsf_remove(sbi->root, path, flags);
 381         __putname(path);
 382         if (err)
 383                 return err;
 384
 385         /* parent directory access/change time changed */
 386         sf_parent_i->force_restat = 1;
 387
 388         return 0;
 389 }
 390
 391 static int vboxsf_dir_rename(struct mnt_idmap *idmap,
 392                              struct inode *old_parent,
 393                              struct dentry *old_dentry,
 394                              struct inode *new_parent,
 395                              struct dentry *new_dentry,
 396                              unsigned int flags)
 397 {
 398         struct vboxsf_sbi *sbi = VBOXSF_SBI(old_parent->i_sb);
 399         struct vboxsf_inode *sf_old_parent_i = VBOXSF_I(old_parent);
 400         struct vboxsf_inode *sf_new_parent_i = VBOXSF_I(new_parent);
 401         u32 shfl_flags = SHFL_RENAME_FILE | SHFL_RENAME_REPLACE_IF_EXISTS;
 402         struct shfl_string *old_path, *new_path;
 403         int err;
 404
 405         if (flags)
 406                 return -EINVAL;
 407
 408         old_path = vboxsf_path_from_dentry(sbi, old_dentry);
 409         if (IS_ERR(old_path))
 410                 return PTR_ERR(old_path);
 411
 412         new_path = vboxsf_path_from_dentry(sbi, new_dentry);
 413         if (IS_ERR(new_path)) {
 414                 err = PTR_ERR(new_path);
 415                 goto err_put_old_path;
 416         }
 417
 418         if (d_inode(old_dentry)->i_mode & S_IFDIR)
 419                 shfl_flags = 0;
 420
 421         err = vboxsf_rename(sbi->root, old_path, new_path, shfl_flags);
 422         if (err == 0) {
 423                 /* parent directories access/change time changed */
 424                 sf_new_parent_i->force_restat = 1;
 425                 sf_old_parent_i->force_restat = 1;
 426         }
 427
 428         __putname(new_path);
 429 err_put_old_path:
 430         __putname(old_path);
 431         return err;
 432 }
 433
 434 static int vboxsf_dir_symlink(struct mnt_idmap *idmap,
 435                               struct inode *parent, struct dentry *dentry,
 436                               const char *symname)
 437 {
 438         struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 439         struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
 440         int symname_size = strlen(symname) + 1;
 441         struct shfl_string *path, *ssymname;
 442         struct shfl_fsobjinfo info;
 443         int err;
 444
 445         path = vboxsf_path_from_dentry(sbi, dentry);
 446         if (IS_ERR(path))
 447                 return PTR_ERR(path);
 448
 449         ssymname = kmalloc(SHFLSTRING_HEADER_SIZE + symname_size, GFP_KERNEL);
 450         if (!ssymname) {
 451                 __putname(path);
 452                 return -ENOMEM;
 453         }
 454         ssymname->length = symname_size - 1;
 455         ssymname->size = symname_size;
 456         memcpy(ssymname->string.utf8, symname, symname_size);
 457
 458         err = vboxsf_symlink(sbi->root, path, ssymname, &info);
 459         kfree(ssymname);
 460         __putname(path);
 461         if (err) {
 462                 /* -EROFS means symlinks are note support -> -EPERM */
 463                 return (err == -EROFS) ? -EPERM : err;
 464         }
 465
 466         err = vboxsf_dir_instantiate(parent, dentry, &info);
 467         if (err)
 468                 return err;
 469
 470         /* parent directory access/change time changed */
 471         sf_parent_i->force_restat = 1;
 472         return 0;
 473 }
 474
 475 const struct inode_operations vboxsf_dir_iops = {
 476         .lookup  = vboxsf_dir_lookup,
 477         .create  = vboxsf_dir_mkfile,
 478         .mkdir   = vboxsf_dir_mkdir,
 479         .atomic_open = vboxsf_dir_atomic_open,
 480         .rmdir   = vboxsf_dir_unlink,
 481         .unlink  = vboxsf_dir_unlink,
 482         .rename  = vboxsf_dir_rename,
 483         .symlink = vboxsf_dir_symlink,
 484         .getattr = vboxsf_getattr,
 485         .setattr = vboxsf_setattr,
 486 };