summaryrefslogtreecommitdiffstats
path: root/OvmfPkg/VirtioFsDxe/SimpleFsOpen.c
blob: a13d4f6a1e2dd08523989ce7edb533803a68699c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
/** @file
  EFI_FILE_PROTOCOL.Open() member function for the Virtio Filesystem driver.

  Copyright (C) 2020, Red Hat, Inc.

  SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#include <Library/BaseLib.h>             // AsciiStrCmp()
#include <Library/MemoryAllocationLib.h> // AllocatePool()

#include "VirtioFsDxe.h"

/**
  Open the root directory, possibly for writing.

  @param[in,out] VirtioFs    The Virtio Filesystem device whose root directory
                             should be opened.

  @param[out] NewHandle      The new EFI_FILE_PROTOCOL instance through which
                             the root directory can be accessed.

  @param[in] OpenForWriting  TRUE if the root directory should be opened for
                             read-write access. FALSE if the root directory
                             should be opened for read-only access. Opening the
                             root directory for read-write access is useful for
                             calling EFI_FILE_PROTOCOL.Flush() or
                             EFI_FILE_PROTOCOL.SetInfo() later, for syncing or
                             touching the root directory, respectively.

  @retval EFI_SUCCESS        The root directory has been opened successfully.

  @retval EFI_ACCESS_DENIED  OpenForWriting is TRUE, but the root directory is
                             marked as read-only.

  @return                    Error codes propagated from underlying functions.
**/
STATIC
EFI_STATUS
OpenRootDirectory (
  IN OUT VIRTIO_FS       *VirtioFs,
  OUT EFI_FILE_PROTOCOL  **NewHandle,
  IN     BOOLEAN         OpenForWriting
  )
{
  EFI_STATUS      Status;
  VIRTIO_FS_FILE  *NewVirtioFsFile;

  //
  // VirtioFsOpenVolume() opens the root directory for read-only access. If the
  // current request is to open the root directory for read-write access, so
  // that EFI_FILE_PROTOCOL.Flush() or EFI_FILE_PROTOCOL.SetInfo()+timestamps
  // can be used on the root directory later, then we have to check for write
  // permission first.
  //
  if (OpenForWriting) {
    VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE  FuseAttr;
    EFI_FILE_INFO                       FileInfo;

    Status = VirtioFsFuseGetAttr (
               VirtioFs,
               VIRTIO_FS_FUSE_ROOT_DIR_NODE_ID,
               &FuseAttr
               );
    if (EFI_ERROR (Status)) {
      return Status;
    }

    Status = VirtioFsFuseAttrToEfiFileInfo (&FuseAttr, &FileInfo);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    if ((FileInfo.Attribute & EFI_FILE_READ_ONLY) != 0) {
      return EFI_ACCESS_DENIED;
    }
  }

  Status = VirtioFsOpenVolume (&VirtioFs->SimpleFs, NewHandle);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  NewVirtioFsFile                   = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (*NewHandle);
  NewVirtioFsFile->IsOpenForWriting = OpenForWriting;
  return EFI_SUCCESS;
}

/**
  Open an existent regular file or non-root directory.

  @param[in,out] VirtioFs      The Virtio Filesystem device on which the
                               regular file or directory should be opened.

  @param[in] DirNodeId         The inode number of the immediate parent
                               directory of the regular file or directory to
                               open.

  @param[in] Name              The single-component filename of the regular
                               file or directory to open, under the immediate
                               parent directory identified by DirNodeId.

  @param[in] OpenForWriting    TRUE if the regular file or directory should be
                               opened for read-write access. FALSE if the
                               regular file or directory should be opened for
                               read-only access. Opening a directory for
                               read-write access is useful for deleting,
                               renaming, syncing or touching the directory
                               later.

  @param[out] NodeId           The inode number of the regular file or
                               directory, returned by the Virtio Filesystem
                               device.

  @param[out] FuseHandle       The open handle to the regular file or
                               directory, returned by the Virtio Filesystem
                               device.

  @param[out] NodeIsDirectory  Set to TRUE on output if Name was found to refer
                               to a directory. Set to FALSE if Name was found
                               to refer to a regular file.

  @retval EFI_SUCCESS        The regular file or directory has been looked up
                             and opened successfully.

  @retval EFI_ACCESS_DENIED  OpenForWriting is TRUE, but the regular file or
                             directory is marked read-only.

  @retval EFI_NOT_FOUND      A directory entry called Name was not found in the
                             directory identified by DirNodeId. (EFI_NOT_FOUND
                             is not returned for any other condition.)

  @return                    Errors propagated from underlying functions. If
                             the error code to propagate were EFI_NOT_FOUND, it
                             is remapped to EFI_DEVICE_ERROR.
**/
STATIC
EFI_STATUS
OpenExistentFileOrDirectory (
  IN OUT VIRTIO_FS  *VirtioFs,
  IN     UINT64     DirNodeId,
  IN     CHAR8      *Name,
  IN     BOOLEAN    OpenForWriting,
  OUT UINT64        *NodeId,
  OUT UINT64        *FuseHandle,
  OUT BOOLEAN       *NodeIsDirectory
  )
{
  EFI_STATUS                          Status;
  UINT64                              ResolvedNodeId;
  VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE  FuseAttr;
  EFI_FILE_INFO                       FileInfo;
  BOOLEAN                             IsDirectory;
  UINT64                              NewFuseHandle;

  Status = VirtioFsFuseLookup (
             VirtioFs,
             DirNodeId,
             Name,
             &ResolvedNodeId,
             &FuseAttr
             );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = VirtioFsFuseAttrToEfiFileInfo (&FuseAttr, &FileInfo);
  if (EFI_ERROR (Status)) {
    goto ForgetResolvedNodeId;
  }

  if (OpenForWriting && ((FileInfo.Attribute & EFI_FILE_READ_ONLY) != 0)) {
    Status = EFI_ACCESS_DENIED;
    goto ForgetResolvedNodeId;
  }

  IsDirectory = (BOOLEAN)((FileInfo.Attribute & EFI_FILE_DIRECTORY) != 0);
  if (IsDirectory) {
    //
    // If OpenForWriting is TRUE here, that's not passed to
    // VirtioFsFuseOpenDir(); it does not affect the FUSE_OPENDIR request we
    // send. OpenForWriting=TRUE will only permit attempts to delete, rename,
    // flush (sync), and touch the directory.
    //
    Status = VirtioFsFuseOpenDir (VirtioFs, ResolvedNodeId, &NewFuseHandle);
  } else {
    Status = VirtioFsFuseOpen (
               VirtioFs,
               ResolvedNodeId,
               OpenForWriting,
               &NewFuseHandle
               );
  }

  if (EFI_ERROR (Status)) {
    goto ForgetResolvedNodeId;
  }

  *NodeId          = ResolvedNodeId;
  *FuseHandle      = NewFuseHandle;
  *NodeIsDirectory = IsDirectory;
  return EFI_SUCCESS;

ForgetResolvedNodeId:
  VirtioFsFuseForget (VirtioFs, ResolvedNodeId);
  return (Status == EFI_NOT_FOUND) ? EFI_DEVICE_ERROR : Status;
}

/**
  Create a directory.

  @param[in,out] VirtioFs  The Virtio Filesystem device on which the directory
                           should be created.

  @param[in] DirNodeId     The inode number of the immediate parent directory
                           of the directory to create.

  @param[in] Name          The single-component filename of the directory to
                           create, under the immediate parent directory
                           identified by DirNodeId.

  @param[out] NodeId       The inode number of the directory created, returned
                           by the Virtio Filesystem device.

  @param[out] FuseHandle   The open handle to the directory created, returned
                           by the Virtio Filesystem device.

  @retval EFI_SUCCESS  The directory has been created successfully.

  @return              Errors propagated from underlying functions.
**/
STATIC
EFI_STATUS
CreateDirectory (
  IN OUT VIRTIO_FS  *VirtioFs,
  IN     UINT64     DirNodeId,
  IN     CHAR8      *Name,
  OUT UINT64        *NodeId,
  OUT UINT64        *FuseHandle
  )
{
  EFI_STATUS  Status;
  UINT64      NewChildDirNodeId;
  UINT64      NewFuseHandle;

  Status = VirtioFsFuseMkDir (VirtioFs, DirNodeId, Name, &NewChildDirNodeId);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = VirtioFsFuseOpenDir (VirtioFs, NewChildDirNodeId, &NewFuseHandle);
  if (EFI_ERROR (Status)) {
    goto RemoveNewChildDir;
  }

  *NodeId     = NewChildDirNodeId;
  *FuseHandle = NewFuseHandle;
  return EFI_SUCCESS;

RemoveNewChildDir:
  VirtioFsFuseRemoveFileOrDir (VirtioFs, DirNodeId, Name, TRUE /* IsDir */);
  VirtioFsFuseForget (VirtioFs, NewChildDirNodeId);
  return Status;
}

/**
  Create a regular file.

  @param[in,out] VirtioFs  The Virtio Filesystem device on which the regular
                           file should be created.

  @param[in] DirNodeId     The inode number of the immediate parent directory
                           of the regular file to create.

  @param[in] Name          The single-component filename of the regular file to
                           create, under the immediate parent directory
                           identified by DirNodeId.

  @param[out] NodeId       The inode number of the regular file created,
                           returned by the Virtio Filesystem device.

  @param[out] FuseHandle   The open handle to the regular file created,
                           returned by the Virtio Filesystem device.

  @retval EFI_SUCCESS  The regular file has been created successfully.

  @return              Errors propagated from underlying functions.
**/
STATIC
EFI_STATUS
CreateRegularFile (
  IN OUT VIRTIO_FS  *VirtioFs,
  IN     UINT64     DirNodeId,
  IN     CHAR8      *Name,
  OUT UINT64        *NodeId,
  OUT UINT64        *FuseHandle
  )
{
  return VirtioFsFuseOpenOrCreate (
           VirtioFs,
           DirNodeId,
           Name,
           NodeId,
           FuseHandle
           );
}

EFI_STATUS
EFIAPI
VirtioFsSimpleFileOpen (
  IN     EFI_FILE_PROTOCOL  *This,
  OUT EFI_FILE_PROTOCOL     **NewHandle,
  IN     CHAR16             *FileName,
  IN     UINT64             OpenMode,
  IN     UINT64             Attributes
  )
{
  VIRTIO_FS_FILE  *VirtioFsFile;
  VIRTIO_FS       *VirtioFs;
  BOOLEAN         OpenForWriting;
  BOOLEAN         PermitCreation;
  BOOLEAN         CreateDirectoryIfCreating;
  VIRTIO_FS_FILE  *NewVirtioFsFile;
  EFI_STATUS      Status;
  CHAR8           *NewCanonicalPath;
  BOOLEAN         RootEscape;
  UINT64          DirNodeId;
  CHAR8           *LastComponent;
  UINT64          NewNodeId;
  UINT64          NewFuseHandle;
  BOOLEAN         NewNodeIsDirectory;

  VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
  VirtioFs     = VirtioFsFile->OwnerFs;

  //
  // Validate OpenMode.
  //
  switch (OpenMode) {
    case EFI_FILE_MODE_READ:
      OpenForWriting = FALSE;
      PermitCreation = FALSE;
      break;
    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE:
      OpenForWriting = TRUE;
      PermitCreation = FALSE;
      break;
    case EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE:
      OpenForWriting = TRUE;
      PermitCreation = TRUE;
      break;
    default:
      return EFI_INVALID_PARAMETER;
  }

  //
  // Set CreateDirectoryIfCreating to suppress incorrect compiler/analyzer
  // warnings.
  //
  CreateDirectoryIfCreating = FALSE;

  //
  // Validate the Attributes requested for the case when the file ends up being
  // created, provided creation is permitted.
  //
  if (PermitCreation) {
    if ((Attributes & ~EFI_FILE_VALID_ATTR) != 0) {
      //
      // Unknown attribute requested.
      //
      return EFI_INVALID_PARAMETER;
    }

    ASSERT (OpenForWriting);
    if ((Attributes & EFI_FILE_READ_ONLY) != 0) {
      DEBUG ((
        DEBUG_ERROR,
        ("%a: Label=\"%s\" CanonicalPathname=\"%a\" FileName=\"%s\" "
         "OpenMode=0x%Lx Attributes=0x%Lx: nonsensical request to possibly "
         "create a file marked read-only, for read-write access\n"),
        __func__,
        VirtioFs->Label,
        VirtioFsFile->CanonicalPathname,
        FileName,
        OpenMode,
        Attributes
        ));
      return EFI_INVALID_PARAMETER;
    }

    CreateDirectoryIfCreating = (BOOLEAN)((Attributes &
                                           EFI_FILE_DIRECTORY) != 0);
  }

  //
  // Referring to a file relative to a regular file makes no sense (or at least
  // it cannot be implemented consistently with how a file is referred to
  // relative to a directory).
  //
  if (!VirtioFsFile->IsDirectory) {
    DEBUG ((
      DEBUG_ERROR,
      ("%a: Label=\"%s\" CanonicalPathname=\"%a\" FileName=\"%s\": "
       "nonsensical request to open a file or directory relative to a regular "
       "file\n"),
      __func__,
      VirtioFs->Label,
      VirtioFsFile->CanonicalPathname,
      FileName
      ));
    return EFI_INVALID_PARAMETER;
  }

  //
  // Allocate the new VIRTIO_FS_FILE object.
  //
  NewVirtioFsFile = AllocatePool (sizeof *NewVirtioFsFile);
  if (NewVirtioFsFile == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  //
  // Create the canonical pathname at which the desired file is expected to
  // exist.
  //
  Status = VirtioFsAppendPath (
             VirtioFsFile->CanonicalPathname,
             FileName,
             &NewCanonicalPath,
             &RootEscape
             );
  if (EFI_ERROR (Status)) {
    goto FreeNewVirtioFsFile;
  }

  if (RootEscape) {
    Status = EFI_ACCESS_DENIED;
    goto FreeNewCanonicalPath;
  }

  //
  // If the desired file is the root directory, just open the volume one more
  // time, without looking up anything.
  //
  if (AsciiStrCmp (NewCanonicalPath, "/") == 0) {
    FreePool (NewCanonicalPath);
    FreePool (NewVirtioFsFile);
    return OpenRootDirectory (VirtioFs, NewHandle, OpenForWriting);
  }

  //
  // Split the new canonical pathname into most specific parent directory
  // (given by DirNodeId) and last pathname component (i.e., immediate child
  // within that parent directory).
  //
  Status = VirtioFsLookupMostSpecificParentDir (
             VirtioFs,
             NewCanonicalPath,
             &DirNodeId,
             &LastComponent
             );
  if (EFI_ERROR (Status)) {
    goto FreeNewCanonicalPath;
  }

  //
  // Set NewNodeIsDirectory to suppress incorrect compiler/analyzer warnings.
  //
  NewNodeIsDirectory = FALSE;

  //
  // Try to open LastComponent directly under DirNodeId, as an existent regular
  // file or directory.
  //
  Status = OpenExistentFileOrDirectory (
             VirtioFs,
             DirNodeId,
             LastComponent,
             OpenForWriting,
             &NewNodeId,
             &NewFuseHandle,
             &NewNodeIsDirectory
             );
  //
  // If LastComponent could not be found under DirNodeId, but the request
  // allows us to create a new entry, attempt creating the requested regular
  // file or directory.
  //
  if ((Status == EFI_NOT_FOUND) && PermitCreation) {
    ASSERT (OpenForWriting);
    if (CreateDirectoryIfCreating) {
      Status = CreateDirectory (
                 VirtioFs,
                 DirNodeId,
                 LastComponent,
                 &NewNodeId,
                 &NewFuseHandle
                 );
    } else {
      Status = CreateRegularFile (
                 VirtioFs,
                 DirNodeId,
                 LastComponent,
                 &NewNodeId,
                 &NewFuseHandle
                 );
    }

    NewNodeIsDirectory = CreateDirectoryIfCreating;
  }

  //
  // Regardless of the branch taken, we're done with DirNodeId.
  //
  if (DirNodeId != VIRTIO_FS_FUSE_ROOT_DIR_NODE_ID) {
    VirtioFsFuseForget (VirtioFs, DirNodeId);
  }

  if (EFI_ERROR (Status)) {
    goto FreeNewCanonicalPath;
  }

  //
  // Populate the new VIRTIO_FS_FILE object.
  //
  NewVirtioFsFile->Signature              = VIRTIO_FS_FILE_SIG;
  NewVirtioFsFile->SimpleFile.Revision    = EFI_FILE_PROTOCOL_REVISION;
  NewVirtioFsFile->SimpleFile.Open        = VirtioFsSimpleFileOpen;
  NewVirtioFsFile->SimpleFile.Close       = VirtioFsSimpleFileClose;
  NewVirtioFsFile->SimpleFile.Delete      = VirtioFsSimpleFileDelete;
  NewVirtioFsFile->SimpleFile.Read        = VirtioFsSimpleFileRead;
  NewVirtioFsFile->SimpleFile.Write       = VirtioFsSimpleFileWrite;
  NewVirtioFsFile->SimpleFile.GetPosition = VirtioFsSimpleFileGetPosition;
  NewVirtioFsFile->SimpleFile.SetPosition = VirtioFsSimpleFileSetPosition;
  NewVirtioFsFile->SimpleFile.GetInfo     = VirtioFsSimpleFileGetInfo;
  NewVirtioFsFile->SimpleFile.SetInfo     = VirtioFsSimpleFileSetInfo;
  NewVirtioFsFile->SimpleFile.Flush       = VirtioFsSimpleFileFlush;
  NewVirtioFsFile->IsDirectory            = NewNodeIsDirectory;
  NewVirtioFsFile->IsOpenForWriting       = OpenForWriting;
  NewVirtioFsFile->OwnerFs                = VirtioFs;
  NewVirtioFsFile->CanonicalPathname      = NewCanonicalPath;
  NewVirtioFsFile->FilePosition           = 0;
  NewVirtioFsFile->NodeId                 = NewNodeId;
  NewVirtioFsFile->FuseHandle             = NewFuseHandle;
  NewVirtioFsFile->FileInfoArray          = NULL;
  NewVirtioFsFile->SingleFileInfoSize     = 0;
  NewVirtioFsFile->NumFileInfo            = 0;
  NewVirtioFsFile->NextFileInfo           = 0;

  //
  // One more file is now open for the filesystem.
  //
  InsertTailList (&VirtioFs->OpenFiles, &NewVirtioFsFile->OpenFilesEntry);

  *NewHandle = &NewVirtioFsFile->SimpleFile;
  return EFI_SUCCESS;

FreeNewCanonicalPath:
  FreePool (NewCanonicalPath);

FreeNewVirtioFsFile:
  FreePool (NewVirtioFsFile);

  return Status;
}