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audk/OvmfPkg/VirtioFsDxe/Helpers.c

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/** @file
Initialization and helper routines for the Virtio Filesystem device.
Copyright (C) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h> // StrLen()
#include <Library/BaseMemoryLib.h> // CopyMem()
#include <Library/MemoryAllocationLib.h> // AllocatePool()
#include <Library/VirtioLib.h> // Virtio10WriteFeatures()
#include "VirtioFsDxe.h"
/**
Read the Virtio Filesystem device configuration structure in full.
@param[in] Virtio The Virtio protocol underlying the VIRTIO_FS object.
@param[out] Config The fully populated VIRTIO_FS_CONFIG structure.
@retval EFI_SUCCESS Config has been filled in.
@return Error codes propagated from Virtio->ReadDevice(). The
contents of Config are indeterminate.
**/
STATIC
EFI_STATUS
VirtioFsReadConfig (
IN VIRTIO_DEVICE_PROTOCOL *Virtio,
OUT VIRTIO_FS_CONFIG *Config
)
{
UINTN Idx;
EFI_STATUS Status;
for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES; Idx++) {
Status = Virtio->ReadDevice (
Virtio, // This
OFFSET_OF (VIRTIO_FS_CONFIG, Tag[Idx]), // FieldOffset
sizeof Config->Tag[Idx], // FieldSize
sizeof Config->Tag[Idx], // BufferSize
&Config->Tag[Idx] // Buffer
);
if (EFI_ERROR (Status)) {
return Status;
}
}
Status = Virtio->ReadDevice (
Virtio, // This
OFFSET_OF (VIRTIO_FS_CONFIG, NumReqQueues), // FieldOffset
sizeof Config->NumReqQueues, // FieldSize
sizeof Config->NumReqQueues, // BufferSize
&Config->NumReqQueues // Buffer
);
return Status;
}
/**
Configure the Virtio Filesystem device underlying VirtioFs.
@param[in,out] VirtioFs The VIRTIO_FS object for which Virtio communication
should be set up. On input, the caller is
responsible for VirtioFs->Virtio having been
initialized. On output, synchronous Virtio
Filesystem commands (primitives) may be submitted to
the device.
@retval EFI_SUCCESS Virtio machinery has been set up.
@retval EFI_UNSUPPORTED The host-side configuration of the Virtio Filesystem
is not supported by this driver.
@return Error codes from underlying functions.
**/
EFI_STATUS
VirtioFsInit (
IN OUT VIRTIO_FS *VirtioFs
)
{
UINT8 NextDevStat;
EFI_STATUS Status;
UINT64 Features;
VIRTIO_FS_CONFIG Config;
UINTN Idx;
UINT64 RingBaseShift;
//
// Execute virtio-v1.1-cs01-87fa6b5d8155, 3.1.1 Driver Requirements: Device
// Initialization.
//
// 1. Reset the device.
//
NextDevStat = 0;
Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// 2. Set the ACKNOWLEDGE status bit [...]
//
NextDevStat |= VSTAT_ACK;
Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// 3. Set the DRIVER status bit [...]
//
NextDevStat |= VSTAT_DRIVER;
Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// 4. Read device feature bits...
//
Status = VirtioFs->Virtio->GetDeviceFeatures (VirtioFs->Virtio, &Features);
if (EFI_ERROR (Status)) {
goto Failed;
}
if ((Features & VIRTIO_F_VERSION_1) == 0) {
Status = EFI_UNSUPPORTED;
goto Failed;
}
//
// No device-specific feature bits have been defined in file "virtio-fs.tex"
// of the virtio spec at <https://github.com/oasis-tcs/virtio-spec.git>, as
// of commit 87fa6b5d8155.
//
Features &= VIRTIO_F_VERSION_1 | VIRTIO_F_IOMMU_PLATFORM;
//
// ... and write the subset of feature bits understood by the [...] driver to
// the device. [...]
// 5. Set the FEATURES_OK status bit.
// 6. Re-read device status to ensure the FEATURES_OK bit is still set [...]
//
Status = Virtio10WriteFeatures (VirtioFs->Virtio, Features, &NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// 7. Perform device-specific setup, including discovery of virtqueues for
// the device, [...] reading [...] the device's virtio configuration space
//
Status = VirtioFsReadConfig (VirtioFs->Virtio, &Config);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// 7.a. Convert the filesystem label from UTF-8 to UCS-2. Only labels with
// printable ASCII code points (U+0020 through U+007E) are supported.
// NUL-terminate at either the terminator we find, or right after the
// original label.
//
for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES && Config.Tag[Idx] != '\0'; Idx++) {
if (Config.Tag[Idx] < 0x20 || Config.Tag[Idx] > 0x7E) {
Status = EFI_UNSUPPORTED;
goto Failed;
}
VirtioFs->Label[Idx] = Config.Tag[Idx];
}
VirtioFs->Label[Idx] = L'\0';
//
// 7.b. We need one queue for sending normal priority requests.
//
if (Config.NumReqQueues < 1) {
Status = EFI_UNSUPPORTED;
goto Failed;
}
//
// 7.c. Fetch and remember the number of descriptors we can place on the
// queue at once. We'll need two descriptors per request, as a minimum --
// request header, response header.
//
Status = VirtioFs->Virtio->SetQueueSel (VirtioFs->Virtio,
VIRTIO_FS_REQUEST_QUEUE);
if (EFI_ERROR (Status)) {
goto Failed;
}
Status = VirtioFs->Virtio->GetQueueNumMax (VirtioFs->Virtio,
&VirtioFs->QueueSize);
if (EFI_ERROR (Status)) {
goto Failed;
}
if (VirtioFs->QueueSize < 2) {
Status = EFI_UNSUPPORTED;
goto Failed;
}
//
// 7.d. [...] population of virtqueues [...]
//
Status = VirtioRingInit (VirtioFs->Virtio, VirtioFs->QueueSize,
&VirtioFs->Ring);
if (EFI_ERROR (Status)) {
goto Failed;
}
Status = VirtioRingMap (VirtioFs->Virtio, &VirtioFs->Ring, &RingBaseShift,
&VirtioFs->RingMap);
if (EFI_ERROR (Status)) {
goto ReleaseQueue;
}
Status = VirtioFs->Virtio->SetQueueAddress (VirtioFs->Virtio,
&VirtioFs->Ring, RingBaseShift);
if (EFI_ERROR (Status)) {
goto UnmapQueue;
}
//
// 8. Set the DRIVER_OK status bit.
//
NextDevStat |= VSTAT_DRIVER_OK;
Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
if (EFI_ERROR (Status)) {
goto UnmapQueue;
}
return EFI_SUCCESS;
UnmapQueue:
VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);
ReleaseQueue:
VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);
Failed:
//
// If any of these steps go irrecoverably wrong, the driver SHOULD set the
// FAILED status bit to indicate that it has given up on the device (it can
// reset the device later to restart if desired). [...]
//
// Virtio access failure here should not mask the original error.
//
NextDevStat |= VSTAT_FAILED;
VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
return Status;
}
/**
De-configure the Virtio Filesystem device underlying VirtioFs.
@param[in] VirtioFs The VIRTIO_FS object for which Virtio communication
should be torn down. On input, the caller is responsible
for having called VirtioFsInit(). On output, Virtio
Filesystem commands (primitives) must no longer be
submitted to the device.
**/
VOID
VirtioFsUninit (
IN OUT VIRTIO_FS *VirtioFs
)
{
//
// Resetting the Virtio device makes it release its resources and forget its
// configuration.
//
VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);
VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);
VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);
}
/**
ExitBootServices event notification function for a Virtio Filesystem object.
This function resets the VIRTIO_FS.Virtio device, causing it to release all
references to guest-side resources. The function may only be called after
VirtioFsInit() returns successfully and before VirtioFsUninit() is called.
@param[in] ExitBootEvent The VIRTIO_FS.ExitBoot event that has been
signaled.
@param[in] VirtioFsAsVoid Pointer to the VIRTIO_FS object, passed in as
(VOID*).
**/
VOID
EFIAPI
VirtioFsExitBoot (
IN EFI_EVENT ExitBootEvent,
IN VOID *VirtioFsAsVoid
)
{
VIRTIO_FS *VirtioFs;
VirtioFs = VirtioFsAsVoid;
DEBUG ((DEBUG_VERBOSE, "%a: VirtioFs=0x%p Label=\"%s\"\n", __FUNCTION__,
VirtioFsAsVoid, VirtioFs->Label));
VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);
}
/**
Validate two VIRTIO_FS_SCATTER_GATHER_LIST objects -- list of request
buffers, list of response buffers -- together.
On input, the caller is required to populate the following fields:
- VIRTIO_FS_IO_VECTOR.Buffer,
- VIRTIO_FS_IO_VECTOR.Size,
- VIRTIO_FS_SCATTER_GATHER_LIST.IoVec,
- VIRTIO_FS_SCATTER_GATHER_LIST.NumVec.
On output (on successful return), the following fields will be
zero-initialized:
- VIRTIO_FS_IO_VECTOR.Mapped,
- VIRTIO_FS_IO_VECTOR.MappedAddress,
- VIRTIO_FS_IO_VECTOR.Mapping,
- VIRTIO_FS_IO_VECTOR.Transferred.
On output (on successful return), the following fields will be calculated:
- VIRTIO_FS_SCATTER_GATHER_LIST.TotalSize.
The function may only be called after VirtioFsInit() returns successfully and
before VirtioFsUninit() is called.
@param[in] VirtioFs The Virtio Filesystem device that the
request-response exchange, expressed via
RequestSgList and ResponseSgList, will be
submitted to.
@param[in,out] RequestSgList The scatter-gather list that describes the
request part of the exchange -- the buffers
that should be sent to the Virtio Filesystem
device in the virtio transfer.
@param[in,out] ResponseSgList The scatter-gather list that describes the
response part of the exchange -- the buffers
that the Virtio Filesystem device should
populate in the virtio transfer. May be NULL
if the exchange with the Virtio Filesystem
device consists of a request only, with the
response part omitted altogether.
@retval EFI_SUCCESS RequestSgList and ResponseSgList have been
validated, output fields have been set.
@retval EFI_INVALID_PARAMETER RequestSgList is NULL.
@retval EFI_INVALID_PARAMETER On input, a
VIRTIO_FS_SCATTER_GATHER_LIST.IoVec field is
NULL, or a
VIRTIO_FS_SCATTER_GATHER_LIST.NumVec field is
zero.
@retval EFI_INVALID_PARAMETER On input, a VIRTIO_FS_IO_VECTOR.Buffer field
is NULL, or a VIRTIO_FS_IO_VECTOR.Size field
is zero.
@retval EFI_UNSUPPORTED (RequestSgList->NumVec +
ResponseSgList->NumVec) exceeds
VirtioFs->QueueSize, meaning that the total
list of buffers cannot be placed on the virtio
queue in a single descriptor chain (with one
descriptor per buffer).
@retval EFI_UNSUPPORTED One of the
VIRTIO_FS_SCATTER_GATHER_LIST.TotalSize fields
would exceed MAX_UINT32.
**/
EFI_STATUS
VirtioFsSgListsValidate (
IN VIRTIO_FS *VirtioFs,
IN OUT VIRTIO_FS_SCATTER_GATHER_LIST *RequestSgList,
IN OUT VIRTIO_FS_SCATTER_GATHER_LIST *ResponseSgList OPTIONAL
)
{
VIRTIO_FS_SCATTER_GATHER_LIST *SgListParam[2];
UINT16 DescriptorsNeeded;
UINTN ListId;
if (RequestSgList == NULL) {
return EFI_INVALID_PARAMETER;
}
SgListParam[0] = RequestSgList;
SgListParam[1] = ResponseSgList;
DescriptorsNeeded = 0;
for (ListId = 0; ListId < ARRAY_SIZE (SgListParam); ListId++) {
VIRTIO_FS_SCATTER_GATHER_LIST *SgList;
UINT32 SgListTotalSize;
UINTN IoVecIdx;
SgList = SgListParam[ListId];
if (SgList == NULL) {
continue;
}
//
// Sanity-check SgList -- it must provide at least one IO Vector.
//
if (SgList->IoVec == NULL || SgList->NumVec == 0) {
return EFI_INVALID_PARAMETER;
}
//
// Make sure that, for each IO Vector in this SgList, a virtio descriptor
// can be added to the virtio queue, after the other descriptors added
// previously.
//
if (SgList->NumVec > (UINTN)(MAX_UINT16 - DescriptorsNeeded) ||
DescriptorsNeeded + SgList->NumVec > VirtioFs->QueueSize) {
return EFI_UNSUPPORTED;
}
DescriptorsNeeded += (UINT16)SgList->NumVec;
SgListTotalSize = 0;
for (IoVecIdx = 0; IoVecIdx < SgList->NumVec; IoVecIdx++) {
VIRTIO_FS_IO_VECTOR *IoVec;
IoVec = &SgList->IoVec[IoVecIdx];
//
// Sanity-check this IoVec -- it must describe a non-empty buffer.
//
if (IoVec->Buffer == NULL || IoVec->Size == 0) {
return EFI_INVALID_PARAMETER;
}
//
// Make sure the cumulative size of all IO Vectors in this SgList remains
// expressible as a UINT32.
//
if (IoVec->Size > MAX_UINT32 - SgListTotalSize) {
return EFI_UNSUPPORTED;
}
SgListTotalSize += (UINT32)IoVec->Size;
//
// Initialize those fields in this IO Vector that will be updated in
// relation to mapping / transfer.
//
IoVec->Mapped = FALSE;
IoVec->MappedAddress = 0;
IoVec->Mapping = NULL;
IoVec->Transferred = 0;
}
//
// Store the cumulative size of all IO Vectors that we have calculated in
// this SgList.
//
SgList->TotalSize = SgListTotalSize;
}
return EFI_SUCCESS;
}
/**
Submit a validated pair of (request buffer list, response buffer list) to the
Virtio Filesystem device.
On input, the pair of VIRTIO_FS_SCATTER_GATHER_LIST objects must have been
validated together, using the VirtioFsSgListsValidate() function.
On output (on successful return), the following fields will be re-initialized
to zero (after temporarily setting them to different values):
- VIRTIO_FS_IO_VECTOR.Mapped,
- VIRTIO_FS_IO_VECTOR.MappedAddress,
- VIRTIO_FS_IO_VECTOR.Mapping.
On output (on successful return), the following fields will be calculated:
- VIRTIO_FS_IO_VECTOR.Transferred.
The function may only be called after VirtioFsInit() returns successfully and
before VirtioFsUninit() is called.
@param[in,out] VirtioFs The Virtio Filesystem device that the
request-response exchange, expressed via
RequestSgList and ResponseSgList, should now
be submitted to.
@param[in,out] RequestSgList The scatter-gather list that describes the
request part of the exchange -- the buffers
that should be sent to the Virtio Filesystem
device in the virtio transfer.
@param[in,out] ResponseSgList The scatter-gather list that describes the
response part of the exchange -- the buffers
that the Virtio Filesystem device should
populate in the virtio transfer. May be NULL
if and only if NULL was passed to
VirtioFsSgListsValidate() as ResponseSgList.
@retval EFI_SUCCESS Transfer complete. The caller should investigate
the VIRTIO_FS_IO_VECTOR.Transferred fields in
ResponseSgList, to ensure coverage of the relevant
response buffers. Subsequently, the caller should
investigate the contents of those buffers.
@retval EFI_DEVICE_ERROR The Virtio Filesystem device reported populating
more response bytes than ResponseSgList->TotalSize.
@return Error codes propagated from
VirtioMapAllBytesInSharedBuffer(), VirtioFlush(),
or VirtioFs->Virtio->UnmapSharedBuffer().
**/
EFI_STATUS
VirtioFsSgListsSubmit (
IN OUT VIRTIO_FS *VirtioFs,
IN OUT VIRTIO_FS_SCATTER_GATHER_LIST *RequestSgList,
IN OUT VIRTIO_FS_SCATTER_GATHER_LIST *ResponseSgList OPTIONAL
)
{
VIRTIO_FS_SCATTER_GATHER_LIST *SgListParam[2];
VIRTIO_MAP_OPERATION SgListVirtioMapOp[ARRAY_SIZE (SgListParam)];
UINT16 SgListDescriptorFlag[ARRAY_SIZE (SgListParam)];
UINTN ListId;
VIRTIO_FS_SCATTER_GATHER_LIST *SgList;
UINTN IoVecIdx;
VIRTIO_FS_IO_VECTOR *IoVec;
EFI_STATUS Status;
DESC_INDICES Indices;
UINT32 TotalBytesWrittenByDevice;
UINT32 BytesPermittedForWrite;
SgListParam[0] = RequestSgList;
SgListVirtioMapOp[0] = VirtioOperationBusMasterRead;
SgListDescriptorFlag[0] = 0;
SgListParam[1] = ResponseSgList;
SgListVirtioMapOp[1] = VirtioOperationBusMasterWrite;
SgListDescriptorFlag[1] = VRING_DESC_F_WRITE;
//
// Map all IO Vectors.
//
for (ListId = 0; ListId < ARRAY_SIZE (SgListParam); ListId++) {
SgList = SgListParam[ListId];
if (SgList == NULL) {
continue;
}
for (IoVecIdx = 0; IoVecIdx < SgList->NumVec; IoVecIdx++) {
IoVec = &SgList->IoVec[IoVecIdx];
//
// Map this IO Vector.
//
Status = VirtioMapAllBytesInSharedBuffer (
VirtioFs->Virtio,
SgListVirtioMapOp[ListId],
IoVec->Buffer,
IoVec->Size,
&IoVec->MappedAddress,
&IoVec->Mapping
);
if (EFI_ERROR (Status)) {
goto Unmap;
}
IoVec->Mapped = TRUE;
}
}
//
// Compose the descriptor chain.
//
VirtioPrepare (&VirtioFs->Ring, &Indices);
for (ListId = 0; ListId < ARRAY_SIZE (SgListParam); ListId++) {
SgList = SgListParam[ListId];
if (SgList == NULL) {
continue;
}
for (IoVecIdx = 0; IoVecIdx < SgList->NumVec; IoVecIdx++) {
UINT16 NextFlag;
IoVec = &SgList->IoVec[IoVecIdx];
//
// Set VRING_DESC_F_NEXT on all except the very last descriptor.
//
NextFlag = VRING_DESC_F_NEXT;
if (ListId == ARRAY_SIZE (SgListParam) - 1 &&
IoVecIdx == SgList->NumVec - 1) {
NextFlag = 0;
}
VirtioAppendDesc (
&VirtioFs->Ring,
IoVec->MappedAddress,
(UINT32)IoVec->Size,
SgListDescriptorFlag[ListId] | NextFlag,
&Indices
);
}
}
//
// Submit the descriptor chain.
//
Status = VirtioFlush (VirtioFs->Virtio, VIRTIO_FS_REQUEST_QUEUE,
&VirtioFs->Ring, &Indices, &TotalBytesWrittenByDevice);
if (EFI_ERROR (Status)) {
goto Unmap;
}
//
// Sanity-check: the Virtio Filesystem device should not have written more
// bytes than what we offered buffers for.
//
if (ResponseSgList == NULL) {
BytesPermittedForWrite = 0;
} else {
BytesPermittedForWrite = ResponseSgList->TotalSize;
}
if (TotalBytesWrittenByDevice > BytesPermittedForWrite) {
Status = EFI_DEVICE_ERROR;
goto Unmap;
}
//
// Update the transfer sizes in the IO Vectors.
//
for (ListId = 0; ListId < ARRAY_SIZE (SgListParam); ListId++) {
SgList = SgListParam[ListId];
if (SgList == NULL) {
continue;
}
for (IoVecIdx = 0; IoVecIdx < SgList->NumVec; IoVecIdx++) {
IoVec = &SgList->IoVec[IoVecIdx];
if (SgListVirtioMapOp[ListId] == VirtioOperationBusMasterRead) {
//
// We report that the Virtio Filesystem device has read all buffers in
// the request.
//
IoVec->Transferred = IoVec->Size;
} else {
//
// Regarding the response, calculate how much of the current IO Vector
// has been populated by the Virtio Filesystem device. In
// "TotalBytesWrittenByDevice", VirtioFlush() reported the total count
// across all device-writeable descriptors, in the order they were
// chained on the ring.
//
IoVec->Transferred = MIN ((UINTN)TotalBytesWrittenByDevice,
IoVec->Size);
TotalBytesWrittenByDevice -= (UINT32)IoVec->Transferred;
}
}
}
//
// By now, "TotalBytesWrittenByDevice" has been exhausted.
//
ASSERT (TotalBytesWrittenByDevice == 0);
//
// We've succeeded; fall through.
//
Unmap:
//
// Unmap all mapped IO Vectors on both the success and the error paths. The
// unmapping occurs in reverse order of mapping, in an attempt to avoid
// memory fragmentation.
//
ListId = ARRAY_SIZE (SgListParam);
while (ListId > 0) {
--ListId;
SgList = SgListParam[ListId];
if (SgList == NULL) {
continue;
}
IoVecIdx = SgList->NumVec;
while (IoVecIdx > 0) {
EFI_STATUS UnmapStatus;
--IoVecIdx;
IoVec = &SgList->IoVec[IoVecIdx];
//
// Unmap this IO Vector, if it has been mapped.
//
if (!IoVec->Mapped) {
continue;
}
UnmapStatus = VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio,
IoVec->Mapping);
//
// Re-set the following fields to the values they initially got from
// VirtioFsSgListsValidate() -- the above unmapping attempt is considered
// final, even if it fails.
//
IoVec->Mapped = FALSE;
IoVec->MappedAddress = 0;
IoVec->Mapping = NULL;
//
// If we are on the success path, but the unmapping failed, we need to
// transparently flip to the failure path -- the caller must learn they
// should not consult the response buffers.
//
// The branch below can be taken at most once.
//
if (!EFI_ERROR (Status) && EFI_ERROR (UnmapStatus)) {
Status = UnmapStatus;
}
}
}
return Status;
}
/**
Set up the fields of a new VIRTIO_FS_FUSE_REQUEST object.
The function may only be called after VirtioFsInit() returns successfully and
before VirtioFsUninit() is called.
@param[in,out] VirtioFs The Virtio Filesystem device that the request is
being prepared for. The "VirtioFs->RequestId" field
will be copied into "Request->Unique". On output (on
successful return), "VirtioFs->RequestId" will be
incremented.
@param[out] Request The VIRTIO_FS_FUSE_REQUEST object whose fields are to
be set.
@param[in] RequestSize The total size of the request, including
sizeof(VIRTIO_FS_FUSE_REQUEST).
@param[in] Opcode The VIRTIO_FS_FUSE_OPCODE that identifies the command
to send.
@param[in] NodeId The inode number of the file that the request refers
to. When Opcode is VirtioFsFuseOpInit, NodeId is
ignored by the Virtio Filesystem device.
@retval EFI_INVALID_PARAMETER RequestSize is smaller than
sizeof(VIRTIO_FS_FUSE_REQUEST).
@retval EFI_OUT_OF_RESOURCES "VirtioFs->RequestId" is MAX_UINT64, and can
be incremented no more.
@retval EFI_SUCCESS Request has been populated,
"VirtioFs->RequestId" has been incremented.
**/
EFI_STATUS
VirtioFsFuseNewRequest (
IN OUT VIRTIO_FS *VirtioFs,
OUT VIRTIO_FS_FUSE_REQUEST *Request,
IN UINT32 RequestSize,
IN VIRTIO_FS_FUSE_OPCODE Opcode,
IN UINT64 NodeId
)
{
if (RequestSize < sizeof *Request) {
return EFI_INVALID_PARAMETER;
}
if (VirtioFs->RequestId == MAX_UINT64) {
return EFI_OUT_OF_RESOURCES;
}
Request->Len = RequestSize;
Request->Opcode = Opcode;
Request->Unique = VirtioFs->RequestId++;
Request->NodeId = NodeId;
Request->Uid = 0;
Request->Gid = 0;
Request->Pid = 1;
Request->Padding = 0;
return EFI_SUCCESS;
}
/**
Check the common FUSE response format.
The first buffer in the response scatter-gather list is assumed a
VIRTIO_FS_FUSE_RESPONSE structure. Subsequent response buffers, if any, up to
and excluding the last one, are assumed fixed size. The last response buffer
may or may not be fixed size, as specified by the caller.
This function may only be called after VirtioFsSgListsSubmit() returns
successfully.
@param[in] ResponseSgList The scatter-gather list that describes the
response part of the exchange -- the buffers that
the Virtio Filesystem device filled in during the
virtio transfer.
@param[in] RequestId The request identifier to which the response is
expected to belong.
@param[out] TailBufferFill If NULL, then the last buffer in ResponseSgList
is considered fixed size. Otherwise, the last
buffer is considered variable size, and on
successful return, TailBufferFill reports the
number of bytes in the last buffer.
@retval EFI_INVALID_PARAMETER TailBufferFill is not NULL (i.e., the last
buffer is considered variable size), and
ResponseSgList->NumVec is 1.
@retval EFI_INVALID_PARAMETER The allocated size of the first buffer does
not match sizeof(VIRTIO_FS_FUSE_RESPONSE).
@retval EFI_PROTOCOL_ERROR The VIRTIO_FS_FUSE_RESPONSE structure in the
first buffer has not been fully populated.
@retval EFI_PROTOCOL_ERROR "VIRTIO_FS_FUSE_RESPONSE.Len" in the first
buffer does not equal the sum of the
individual buffer sizes (as populated).
@retval EFI_PROTOCOL_ERROR "VIRTIO_FS_FUSE_RESPONSE.Unique" in the first
buffer does not equal RequestId.
@retval EFI_PROTOCOL_ERROR "VIRTIO_FS_FUSE_RESPONSE.Error" in the first
buffer is zero, but a subsequent fixed size
buffer has not been fully populated.
@retval EFI_DEVICE_ERROR "VIRTIO_FS_FUSE_RESPONSE.Error" in the first
buffer is nonzero. The caller may investigate
"VIRTIO_FS_FUSE_RESPONSE.Error". Note that the
completeness of the subsequent fixed size
buffers is not verified in this case.
@retval EFI_SUCCESS Verification successful.
**/
EFI_STATUS
VirtioFsFuseCheckResponse (
IN VIRTIO_FS_SCATTER_GATHER_LIST *ResponseSgList,
IN UINT64 RequestId,
OUT UINTN *TailBufferFill
)
{
UINTN NumFixedSizeVec;
VIRTIO_FS_FUSE_RESPONSE *CommonResp;
UINT32 TotalTransferred;
UINTN Idx;
//
// Ensured by VirtioFsSgListsValidate().
//
ASSERT (ResponseSgList->NumVec > 0);
if (TailBufferFill == NULL) {
//
// All buffers are considered fixed size.
//
NumFixedSizeVec = ResponseSgList->NumVec;
} else {
//
// If the last buffer is variable size, then we need that buffer to be
// different from the first buffer, which is considered a
// VIRTIO_FS_FUSE_RESPONSE (fixed size) structure.
//
if (ResponseSgList->NumVec == 1) {
return EFI_INVALID_PARAMETER;
}
NumFixedSizeVec = ResponseSgList->NumVec - 1;
}
//
// The first buffer is supposed to carry a (fully populated)
// VIRTIO_FS_FUSE_RESPONSE structure.
//
if (ResponseSgList->IoVec[0].Size != sizeof *CommonResp) {
return EFI_INVALID_PARAMETER;
}
if (ResponseSgList->IoVec[0].Transferred != ResponseSgList->IoVec[0].Size) {
return EFI_PROTOCOL_ERROR;
}
//
// FUSE must report the same number of bytes, written by the Virtio
// Filesystem device, as the virtio transport does.
//
CommonResp = ResponseSgList->IoVec[0].Buffer;
TotalTransferred = 0;
for (Idx = 0; Idx < ResponseSgList->NumVec; Idx++) {
//
// Integer overflow and truncation are not possible, based on
// VirtioFsSgListsValidate() and VirtioFsSgListsSubmit().
//
TotalTransferred += (UINT32)ResponseSgList->IoVec[Idx].Transferred;
}
if (CommonResp->Len != TotalTransferred) {
return EFI_PROTOCOL_ERROR;
}
//
// Enforce that FUSE match our request ID in the response.
//
if (CommonResp->Unique != RequestId) {
return EFI_PROTOCOL_ERROR;
}
//
// If there is an explicit error report, skip checking the transfer
// counts for the rest of the fixed size buffers.
//
if (CommonResp->Error != 0) {
return EFI_DEVICE_ERROR;
}
//
// There was no error reported, so we require that the Virtio Filesystem
// device populate all fixed size buffers. We checked this for the very first
// buffer above; let's check the rest (if any).
//
ASSERT (NumFixedSizeVec >= 1);
for (Idx = 1; Idx < NumFixedSizeVec; Idx++) {
if (ResponseSgList->IoVec[Idx].Transferred !=
ResponseSgList->IoVec[Idx].Size) {
return EFI_PROTOCOL_ERROR;
}
}
//
// If the last buffer is considered variable size, report its filled size.
//
if (TailBufferFill != NULL) {
*TailBufferFill = ResponseSgList->IoVec[NumFixedSizeVec].Transferred;
}
return EFI_SUCCESS;
}
/**
An ad-hoc function for mapping FUSE (well, Linux) "errno" values to
EFI_STATUS.
@param[in] Errno The "VIRTIO_FS_FUSE_RESPONSE.Error" value, returned by the
Virtio Filesystem device. The value is expected to be
negative.
@return An EFI_STATUS error code that's deemed a passable
mapping for the Errno value.
@retval EFI_DEVICE_ERROR Fallback EFI_STATUS code for unrecognized Errno
values.
**/
EFI_STATUS
VirtioFsErrnoToEfiStatus (
IN INT32 Errno
)
{
switch (Errno) {
case -1: // EPERM Operation not permitted
return EFI_SECURITY_VIOLATION;
case -2: // ENOENT No such file or directory
case -3: // ESRCH No such process
case -6: // ENXIO No such device or address
case -10: // ECHILD No child processes
case -19: // ENODEV No such device
case -49: // EUNATCH Protocol driver not attached
case -65: // ENOPKG Package not installed
case -79: // ELIBACC Can not access a needed shared library
case -126: // ENOKEY Required key not available
return EFI_NOT_FOUND;
case -4: // EINTR Interrupted system call
case -11: // EAGAIN, EWOULDBLOCK Resource temporarily unavailable
case -16: // EBUSY Device or resource busy
case -26: // ETXTBSY Text file busy
case -35: // EDEADLK, EDEADLOCK Resource deadlock avoided
case -39: // ENOTEMPTY Directory not empty
case -42: // ENOMSG No message of desired type
case -61: // ENODATA No data available
case -85: // ERESTART Interrupted system call should be restarted
return EFI_NOT_READY;
case -5: // EIO Input/output error
case -45: // EL2NSYNC Level 2 not synchronized
case -46: // EL3HLT Level 3 halted
case -47: // EL3RST Level 3 reset
case -51: // EL2HLT Level 2 halted
case -121: // EREMOTEIO Remote I/O error
case -133: // EHWPOISON Memory page has hardware error
return EFI_DEVICE_ERROR;
case -7: // E2BIG Argument list too long
case -36: // ENAMETOOLONG File name too long
case -90: // EMSGSIZE Message too long
return EFI_BAD_BUFFER_SIZE;
case -8: // ENOEXEC Exec format error
case -15: // ENOTBLK Block device required
case -18: // EXDEV Invalid cross-device link
case -20: // ENOTDIR Not a directory
case -21: // EISDIR Is a directory
case -25: // ENOTTY Inappropriate ioctl for device
case -27: // EFBIG File too large
case -29: // ESPIPE Illegal seek
case -38: // ENOSYS Function not implemented
case -59: // EBFONT Bad font file format
case -60: // ENOSTR Device not a stream
case -83: // ELIBEXEC Cannot exec a shared library directly
case -88: // ENOTSOCK Socket operation on non-socket
case -91: // EPROTOTYPE Protocol wrong type for socket
case -92: // ENOPROTOOPT Protocol not available
case -93: // EPROTONOSUPPORT Protocol not supported
case -94: // ESOCKTNOSUPPORT Socket type not supported
case -95: // ENOTSUP, EOPNOTSUPP Operation not supported
case -96: // EPFNOSUPPORT Protocol family not supported
case -97: // EAFNOSUPPORT Address family not supported by protocol
case -99: // EADDRNOTAVAIL Cannot assign requested address
case -118: // ENOTNAM Not a XENIX named type file
case -120: // EISNAM Is a named type file
case -124: // EMEDIUMTYPE Wrong medium type
return EFI_UNSUPPORTED;
case -9: // EBADF Bad file descriptor
case -14: // EFAULT Bad address
case -44: // ECHRNG Channel number out of range
case -48: // ELNRNG Link number out of range
case -53: // EBADR Invalid request descriptor
case -56: // EBADRQC Invalid request code
case -57: // EBADSLT Invalid slot
case -76: // ENOTUNIQ Name not unique on network
case -84: // EILSEQ Invalid or incomplete multibyte or wide character
return EFI_NO_MAPPING;
case -12: // ENOMEM Cannot allocate memory
case -23: // ENFILE Too many open files in system
case -24: // EMFILE Too many open files
case -31: // EMLINK Too many links
case -37: // ENOLCK No locks available
case -40: // ELOOP Too many levels of symbolic links
case -50: // ENOCSI No CSI structure available
case -55: // ENOANO No anode
case -63: // ENOSR Out of streams resources
case -82: // ELIBMAX Attempting to link in too many shared libraries
case -87: // EUSERS Too many users
case -105: // ENOBUFS No buffer space available
case -109: // ETOOMANYREFS Too many references: cannot splice
case -119: // ENAVAIL No XENIX semaphores available
case -122: // EDQUOT Disk quota exceeded
return EFI_OUT_OF_RESOURCES;
case -13: // EACCES Permission denied
return EFI_ACCESS_DENIED;
case -17: // EEXIST File exists
case -98: // EADDRINUSE Address already in use
case -106: // EISCONN Transport endpoint is already connected
case -114: // EALREADY Operation already in progress
case -115: // EINPROGRESS Operation now in progress
return EFI_ALREADY_STARTED;
case -22: // EINVAL Invalid argument
case -33: // EDOM Numerical argument out of domain
return EFI_INVALID_PARAMETER;
case -28: // ENOSPC No space left on device
case -54: // EXFULL Exchange full
return EFI_VOLUME_FULL;
case -30: // EROFS Read-only file system
return EFI_WRITE_PROTECTED;
case -32: // EPIPE Broken pipe
case -43: // EIDRM Identifier removed
case -67: // ENOLINK Link has been severed
case -68: // EADV Advertise error
case -69: // ESRMNT Srmount error
case -70: // ECOMM Communication error on send
case -73: // EDOTDOT RFS specific error
case -78: // EREMCHG Remote address changed
case -86: // ESTRPIPE Streams pipe error
case -102: // ENETRESET Network dropped connection on reset
case -103: // ECONNABORTED Software caused connection abort
case -104: // ECONNRESET Connection reset by peer
case -116: // ESTALE Stale file handle
case -125: // ECANCELED Operation canceled
case -128: // EKEYREVOKED Key has been revoked
case -129: // EKEYREJECTED Key was rejected by service
case -130: // EOWNERDEAD Owner died
case -131: // ENOTRECOVERABLE State not recoverable
return EFI_ABORTED;
case -34: // ERANGE Numerical result out of range
case -75: // EOVERFLOW Value too large for defined data type
return EFI_BUFFER_TOO_SMALL;
case -52: // EBADE Invalid exchange
case -108: // ESHUTDOWN Cannot send after transport endpoint shutdown
case -111: // ECONNREFUSED Connection refused
return EFI_END_OF_FILE;
case -62: // ETIME Timer expired
case -110: // ETIMEDOUT Connection timed out
case -127: // EKEYEXPIRED Key has expired
return EFI_TIMEOUT;
case -64: // ENONET Machine is not on the network
case -66: // EREMOTE Object is remote
case -72: // EMULTIHOP Multihop attempted
case -100: // ENETDOWN Network is down
case -101: // ENETUNREACH Network is unreachable
case -112: // EHOSTDOWN Host is down
case -113: // EHOSTUNREACH No route to host
case -123: // ENOMEDIUM No medium found
case -132: // ERFKILL Operation not possible due to RF-kill
return EFI_NO_MEDIA;
case -71: // EPROTO Protocol error
return EFI_PROTOCOL_ERROR;
case -74: // EBADMSG Bad message
case -77: // EBADFD File descriptor in bad state
case -80: // ELIBBAD Accessing a corrupted shared library
case -81: // ELIBSCN .lib section in a.out corrupted
case -117: // EUCLEAN Structure needs cleaning
return EFI_VOLUME_CORRUPTED;
case -89: // EDESTADDRREQ Destination address required
case -107: // ENOTCONN Transport endpoint is not connected
return EFI_NOT_STARTED;
default:
break;
}
return EFI_DEVICE_ERROR;
}
//
// Parser states for canonicalizing a POSIX pathname.
//
typedef enum {
ParserInit, // just starting
ParserEnd, // finished
ParserSlash, // slash(es) seen
ParserDot, // one dot seen since last slash
ParserDotDot, // two dots seen since last slash
ParserNormal, // a different sequence seen
} PARSER_STATE;
/**
Strip the trailing slash from the parser's output buffer, unless the trailing
slash stands for the root directory.
@param[in] Buffer The parser's output buffer. Only used for
sanity-checking.
@param[in,out] Position On entry, points at the next character to produce
(i.e., right past the end of the output written by
the parser thus far). The last character in the
parser's output buffer is a slash. On return, the
slash is stripped, by decrementing Position by one.
If this action would remove the slash character
standing for the root directory, then the function
has no effect.
**/
STATIC
VOID
ParserStripSlash (
IN CHAR8 *Buffer,
IN OUT UINTN *Position
)
{
ASSERT (*Position >= 1);
ASSERT (Buffer[*Position - 1] == '/');
if (*Position == 1) {
return;
}
(*Position)--;
}
/**
Produce one character in the parser's output buffer.
@param[out] Buffer The parser's output buffer. On return, Char8 will
have been written.
@param[in,out] Position On entry, points at the next character to produce
(i.e., right past the end of the output written by
the parser thus far). On return, Position is
incremented by one.
@param[in] Size Total allocated size of the parser's output buffer.
Used for sanity-checking.
@param[in] Char8 The character to place in the output buffer.
**/
STATIC
VOID
ParserCopy (
OUT CHAR8 *Buffer,
IN OUT UINTN *Position,
IN UINTN Size,
IN CHAR8 Char8
)
{
ASSERT (*Position < Size);
Buffer[(*Position)++] = Char8;
}
/**
Rewind the last single-dot in the parser's output buffer.
@param[in] Buffer The parser's output buffer. Only used for
sanity-checking.
@param[in,out] Position On entry, points at the next character to produce
(i.e., right past the end of the output written by
the parser thus far); the parser's output buffer
ends with the characters ('/', '.'). On return, the
dot is rewound by decrementing Position by one; a
slash character will reside at the new end of the
parser's output buffer.
**/
STATIC
VOID
ParserRewindDot (
IN CHAR8 *Buffer,
IN OUT UINTN *Position
)
{
ASSERT (*Position >= 2);
ASSERT (Buffer[*Position - 1] == '.');
ASSERT (Buffer[*Position - 2] == '/');
(*Position)--;
}
/**
Rewind the last dot-dot in the parser's output buffer.
@param[in] Buffer The parser's output buffer. Only used for
sanity-checking.
@param[in,out] Position On entry, points at the next character to produce
(i.e., right past the end of the output written by
the parser thus far); the parser's output buffer
ends with the characters ('/', '.', '.'). On return,
the ('.', '.') pair is rewound unconditionally, by
decrementing Position by two; a slash character
resides at the new end of the parser's output
buffer.
If this slash character stands for the root
directory, then RootEscape is set to TRUE.
Otherwise (i.e., if this slash character is not the
one standing for the root directory), then the slash
character, and the pathname component preceding it,
are removed by decrementing Position further. In
this case, the slash character preceding the removed
pathname component will reside at the new end of the
parser's output buffer.
@param[out] RootEscape Set to TRUE on output if the dot-dot component tries
to escape the root directory, as described above.
Otherwise, RootEscape is not modified.
**/
STATIC
VOID
ParserRewindDotDot (
IN CHAR8 *Buffer,
IN OUT UINTN *Position,
OUT BOOLEAN *RootEscape
)
{
ASSERT (*Position >= 3);
ASSERT (Buffer[*Position - 1] == '.');
ASSERT (Buffer[*Position - 2] == '.');
ASSERT (Buffer[*Position - 3] == '/');
(*Position) -= 2;
if (*Position == 1) {
//
// Root directory slash reached; don't try to climb higher.
//
*RootEscape = TRUE;
return;
}
//
// Skip slash.
//
(*Position)--;
//
// Scan until next slash to the left.
//
do {
ASSERT (*Position > 0);
(*Position)--;
} while (Buffer[*Position] != '/');
(*Position)++;
}
/**
Append the UEFI-style RhsPath16 to the POSIX-style, canonical format
LhsPath8. Output the POSIX-style, canonical format result in ResultPath, as a
dynamically allocated string.
Canonicalization (aka sanitization) establishes the following properties:
- ResultPath is absolute (starts with "/"),
- dot (.) and dot-dot (..) components are resolved/eliminated in ResultPath,
with the usual semantics,
- ResultPath uses forward slashes,
- sequences of slashes are squashed in ResultPath,
- the printable ASCII character set covers ResultPath,
- CHAR8 encoding is used in ResultPath,
- no trailing slash present in ResultPath except for the standalone root
directory,
- the length of ResultPath is at most VIRTIO_FS_MAX_PATHNAME_LENGTH.
Any dot-dot in RhsPath16 that would remove the root directory is dropped, and
reported through RootEscape, without failing the function call.
@param[in] LhsPath8 Identifies the base directory. The caller is
responsible for ensuring that LhsPath8 conform to
the above canonical pathname format on entry.
@param[in] RhsPath16 Identifies the desired file with a UEFI-style CHAR16
pathname. If RhsPath16 starts with a backslash, then
RhsPath16 is considered absolute, and LhsPath8 is
ignored; RhsPath16 is sanitized in isolation, for
producing ResultPath8. Otherwise (i.e., if RhsPath16
is relative), RhsPath16 is transliterated to CHAR8,
and naively appended to LhsPath8. The resultant
fused pathname is then sanitized, to produce
ResultPath8.
@param[out] ResultPath8 The POSIX-style, canonical format pathname that
leads to the file desired by the caller. After use,
the caller is responsible for freeing ResultPath8.
@param[out] RootEscape Set to TRUE if at least one dot-dot component in
RhsPath16 attempted to escape the root directory;
set to FALSE otherwise.
@retval EFI_SUCCESS ResultPath8 has been produced. RootEscape has
been output.
@retval EFI_INVALID_PARAMETER RhsPath16 is zero-length.
@retval EFI_INVALID_PARAMETER RhsPath16 failed the
VIRTIO_FS_MAX_PATHNAME_LENGTH check.
@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
@retval EFI_OUT_OF_RESOURCES ResultPath8 would have failed the
VIRTIO_FS_MAX_PATHNAME_LENGTH check.
@retval EFI_UNSUPPORTED RhsPath16 contains a character that either
falls outside of the printable ASCII set, or
is a forward slash.
**/
EFI_STATUS
VirtioFsAppendPath (
IN CHAR8 *LhsPath8,
IN CHAR16 *RhsPath16,
OUT CHAR8 **ResultPath8,
OUT BOOLEAN *RootEscape
)
{
UINTN RhsLen;
CHAR8 *RhsPath8;
UINTN Idx;
EFI_STATUS Status;
UINTN SizeToSanitize;
CHAR8 *BufferToSanitize;
CHAR8 *SanitizedBuffer;
PARSER_STATE State;
UINTN SanitizedPosition;
//
// Appending an empty pathname is not allowed.
//
RhsLen = StrLen (RhsPath16);
if (RhsLen == 0) {
return EFI_INVALID_PARAMETER;
}
//
// Enforce length restriction on RhsPath16.
//
if (RhsLen > VIRTIO_FS_MAX_PATHNAME_LENGTH) {
return EFI_INVALID_PARAMETER;
}
//
// Transliterate RhsPath16 to RhsPath8 by:
// - rejecting RhsPath16 if a character outside of printable ASCII is seen,
// - rejecting RhsPath16 if a forward slash is seen,
// - replacing backslashes with forward slashes,
// - casting the characters from CHAR16 to CHAR8.
//
RhsPath8 = AllocatePool (RhsLen + 1);
if (RhsPath8 == NULL) {
return EFI_OUT_OF_RESOURCES;
}
for (Idx = 0; RhsPath16[Idx] != L'\0'; Idx++) {
if (RhsPath16[Idx] < 0x20 || RhsPath16[Idx] > 0x7E ||
RhsPath16[Idx] == L'/') {
Status = EFI_UNSUPPORTED;
goto FreeRhsPath8;
}
RhsPath8[Idx] = (CHAR8)((RhsPath16[Idx] == L'\\') ? L'/' : RhsPath16[Idx]);
}
RhsPath8[Idx++] = '\0';
//
// Now prepare the input for the canonicalization (squashing of sequences of
// forward slashes, and eliminating . (dot) and .. (dot-dot) pathname
// components).
//
// The sanitized path can never be longer than the naive concatenation of the
// left hand side and right hand side paths, so we'll use the catenated size
// for allocating the sanitized output too.
//
if (RhsPath8[0] == '/') {
//
// If the right hand side path is absolute, then it is not appended to the
// left hand side path -- it *replaces* the left hand side path.
//
SizeToSanitize = RhsLen + 1;
BufferToSanitize = RhsPath8;
} else {
//
// If the right hand side path is relative, then it is appended (naively)
// to the left hand side.
//
UINTN LhsLen;
LhsLen = AsciiStrLen (LhsPath8);
SizeToSanitize = LhsLen + 1 + RhsLen + 1;
BufferToSanitize = AllocatePool (SizeToSanitize);
if (BufferToSanitize == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto FreeRhsPath8;
}
CopyMem (BufferToSanitize, LhsPath8, LhsLen);
BufferToSanitize[LhsLen] = '/';
CopyMem (BufferToSanitize + LhsLen + 1, RhsPath8, RhsLen + 1);
}
//
// Allocate the output buffer.
//
SanitizedBuffer = AllocatePool (SizeToSanitize);
if (SanitizedBuffer == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto FreeBufferToSanitize;
}
//
// State machine for parsing the input and producing the canonical output
// follows.
//
*RootEscape = FALSE;
Idx = 0;
State = ParserInit;
SanitizedPosition = 0;
do {
CHAR8 Chr8;
ASSERT (Idx < SizeToSanitize);
Chr8 = BufferToSanitize[Idx++];
switch (State) {
case ParserInit: // just starting
ASSERT (Chr8 == '/');
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserSlash;
break;
case ParserSlash: // slash(es) seen
switch (Chr8) {
case '\0':
ParserStripSlash (SanitizedBuffer, &SanitizedPosition);
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserEnd;
break;
case '/':
//
// skip & stay in same state
//
break;
case '.':
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserDot;
break;
default:
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserNormal;
break;
}
break;
case ParserDot: // one dot seen since last slash
switch (Chr8) {
case '\0':
ParserRewindDot (SanitizedBuffer, &SanitizedPosition);
ParserStripSlash (SanitizedBuffer, &SanitizedPosition);
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserEnd;
break;
case '/':
ParserRewindDot (SanitizedBuffer, &SanitizedPosition);
State = ParserSlash;
break;
case '.':
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserDotDot;
break;
default:
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserNormal;
break;
}
break;
case ParserDotDot: // two dots seen since last slash
switch (Chr8) {
case '\0':
ParserRewindDotDot (SanitizedBuffer, &SanitizedPosition, RootEscape);
ParserStripSlash (SanitizedBuffer, &SanitizedPosition);
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserEnd;
break;
case '/':
ParserRewindDotDot (SanitizedBuffer, &SanitizedPosition, RootEscape);
State = ParserSlash;
break;
case '.':
//
// fall through
//
default:
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserNormal;
break;
}
break;
case ParserNormal: // a different sequence seen
switch (Chr8) {
case '\0':
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserEnd;
break;
case '/':
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
State = ParserSlash;
break;
case '.':
//
// fall through
//
default:
//
// copy and stay in same state
//
ParserCopy (SanitizedBuffer, &SanitizedPosition, SizeToSanitize, Chr8);
break;
}
break;
default:
ASSERT (FALSE);
break;
}
} while (State != ParserEnd);
//
// Ensure length invariant on ResultPath8.
//
ASSERT (SanitizedPosition >= 2);
if (SanitizedPosition - 1 > VIRTIO_FS_MAX_PATHNAME_LENGTH) {
Status = EFI_OUT_OF_RESOURCES;
goto FreeSanitizedBuffer;
}
*ResultPath8 = SanitizedBuffer;
SanitizedBuffer = NULL;
Status = EFI_SUCCESS;
//
// Fall through.
//
FreeSanitizedBuffer:
if (SanitizedBuffer != NULL) {
FreePool (SanitizedBuffer);
}
FreeBufferToSanitize:
if (RhsPath8[0] != '/') {
FreePool (BufferToSanitize);
}
FreeRhsPath8:
FreePool (RhsPath8);
return Status;
}
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