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