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