| 1 | /** @file
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| 2 | EFI_FILE_PROTOCOL.Write() member function for the Virtio Filesystem driver.
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| 3 |
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| 4 | Copyright (C) 2020, Red Hat, Inc.
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| 5 |
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| 6 | SPDX-License-Identifier: BSD-2-Clause-Patent
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| 7 | **/
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| 8 |
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| 9 | #include "VirtioFsDxe.h"
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| 10 |
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| 11 | EFI_STATUS
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| 12 | EFIAPI
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| 13 | VirtioFsSimpleFileWrite (
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| 14 | IN EFI_FILE_PROTOCOL *This,
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| 15 | IN OUT UINTN *BufferSize,
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| 16 | IN VOID *Buffer
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| 17 | )
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| 18 | {
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| 19 | VIRTIO_FS_FILE *VirtioFsFile;
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| 20 | VIRTIO_FS *VirtioFs;
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| 21 | EFI_STATUS Status;
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| 22 | UINTN Transferred;
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| 23 | UINTN Left;
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| 24 |
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| 25 | VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
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| 26 | VirtioFs = VirtioFsFile->OwnerFs;
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| 27 |
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| 28 | if (VirtioFsFile->IsDirectory) {
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| 29 | return EFI_UNSUPPORTED;
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| 30 | }
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| 31 |
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| 32 | if (!VirtioFsFile->IsOpenForWriting) {
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| 33 | return EFI_ACCESS_DENIED;
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| 34 | }
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| 35 |
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| 36 | Status = EFI_SUCCESS;
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| 37 | Transferred = 0;
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| 38 | Left = *BufferSize;
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| 39 | while (Left > 0) {
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| 40 | UINT32 WriteSize;
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| 41 |
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| 42 | //
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| 43 | // Honor the write buffer size limit.
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| 44 | //
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| 45 | WriteSize = (UINT32)MIN ((UINTN)VirtioFs->MaxWrite, Left);
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| 46 | Status = VirtioFsFuseWrite (
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| 47 | VirtioFs,
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| 48 | VirtioFsFile->NodeId,
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| 49 | VirtioFsFile->FuseHandle,
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| 50 | VirtioFsFile->FilePosition + Transferred,
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| 51 | &WriteSize,
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| 52 | (UINT8 *)Buffer + Transferred
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| 53 | );
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| 54 | if (!EFI_ERROR (Status) && (WriteSize == 0)) {
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| 55 | //
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| 56 | // Progress should have been made.
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| 57 | //
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| 58 | Status = EFI_DEVICE_ERROR;
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| 59 | }
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| 60 |
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| 61 | if (EFI_ERROR (Status)) {
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| 62 | break;
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| 63 | }
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| 64 |
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| 65 | Transferred += WriteSize;
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| 66 | Left -= WriteSize;
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| 67 | }
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| 68 |
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| 69 | *BufferSize = Transferred;
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| 70 | VirtioFsFile->FilePosition += Transferred;
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| 71 | //
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| 72 | // According to the UEFI spec,
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| 73 | //
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| 74 | // - 'Partial writes only occur when there has been a data error during the
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| 75 | // write attempt (such as "file space full")', and
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| 76 | //
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| 77 | // - (as an example) EFI_VOLUME_FULL is returned when 'The volume is full'.
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| 78 | //
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| 79 | // These together imply that after a partial write, we have to return an
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| 80 | // error. In other words, (Transferred > 0) is inconsequential for the return
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| 81 | // value.
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| 82 | //
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| 83 | return Status;
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| 84 | }
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